Natural Nicotine Heals Honey Bees

January 23, 2017

NEONICOTINOID INSECTICIDES (e.g. thiamethoxam, imidacloprid, clothianidin) developed at Bayer Japan as safer alternatives (e.g. to human spray applicators) to the natural nicotine once widely used by farmers and gardeners, is now suspected of contributing to honey bee health problems like learning disorders and colony collapse. In contrast, natural nicotine, found in honey produced by bees working tobacco fields, as well as in pollen, nectar, leaves and other plant parts, is a nutrient and medicine helping to heal weak honey bee colonies, said Susan Nicolson of South Africa’s University of Pretoria at “Entomology Without Borders,” a joint meeting of the International Congress of Entomology (ICE) and the Entomological Society of America (ESA) in Orlando, FL.

Natural nicotine, even if produced organically in a sustainable recycling sort of way from tobacco waste products, is mostly shunned in organic farming and gardening. “Over 120 million sites will be returned on a web search on tobacco, but most will not be associated with plant science,” wrote USDA-ARS researcher T.C. Tso in Tobacco Research and Its Relevance to Science, Medicine and Industry. “Many plant scientists in academic institutions cannot obtain grant support for projects using tobacco as a research tool. Some even have to avoid tobacco because of the applying of ‘political correctness’ to academic research. The tobacco plant has served as a valuable tool since the dawn of plant and biological sciences, so it is indeed a great loss to scientific progress that a research tool already invested with so many resources and about which there is such abundant knowledge and such great potential for new advancement is now being wasted.”

Honey bees readily consume bitter alkaloids such as nicotine mixed in sugary plant nectars. Adult honey bees excel at detoxifying alkaloids such as nicotine, which should not be surprising, as survival depends on it. Younger, larval honey bees have fewer enzymes to detoxify nicotine, but also survive quite well even when their royal jelly contains high levels of nicotine. Honey bees and insects immune to nicotine, such as green peach (peach-potato) aphids, transform nicotine into less toxic butanoic acid. A knotty question naturally arises: If natural nicotine heals honey bees, why are synthetic neonicotinoids so terribly different? Are natural compounds like nicotine inherently more beneficial and their synthetic analogs (e.g. neonicotinoids) inherently bad, perhaps due to subtle differences in molecular structure? If bees and other pollinators are a major concern, perhaps natural product restrictions on nicotine need to be relaxed to provide competition to the synthetic neonicotinoids.

“Alkaloids, especially in the nicotine family, have been the main focus of tobacco research because alkaloids are the characteristic product of tobacco,” writes Tso. Dozens of other tobacco molecules are relatively overlooked, including sugar compounds providing least-toxic botanical insect and mite control. Anabasine (neonicotine), an alkaloid found in tobacco and other plants, has also been widely used as a natural insecticide. Strangely enough, anabasine is also an insect attractant and a poison gland product of Aphaenogaster ants. In a strange urban twist to the wild bird practice of lining nests with medicinal herbs emitting essential oils counteracting parasites: Researchers in Mexico discovered urban birds lining nests with cigarette butts to similar advantage. In times past, organic gardeners soaked cigarette butts in water to get a nicotine spray brew. Historically, most commercial nicotine insecticide used on farms and gardens was a sustainable tobacco waste extract.

There are 60-80 described tobacco or Nicotiana species, some available in seed catalogs and grown as ornamentals. Most Nicotiana species grow wild in the Americas, with some in Australia and Africa. “Tobacco plants are easy to grow and have a short growing period,” writes Tso. “Each tobacco plant may produce 14 g or about 150,000 seeds which may provide seedlings for 2 to 5 acres (1–3 ha) of field tobacco, depending on the type.” In Europe, oil extracted from tobacco seeds is being explored for an alternative bio-diesel fuel industry, with dry leftovers as animal feed.

Native American Nicotiana species are being integrated into China’s ancient agricultural interplanting tradition. When tobacco is interplanted in vineyard rows, tobacco roots and grape roots intermingle. Perhaps some sort of biological soil fumigation occurs. Whatever the mechanism, vineyards are cleansed of soil-dwelling phylloxera aphids, a pest that almost destroyed wine grape growing in France in the 1800s and is still a worldwide problem. According to the journal Chinese Tobacco Science, intercropping tobacco with sweet potato also alleviates soil and other pest problems, maximizing profits per unit area of land. Burley tobacco is intercropped with cabbage and other vegetable crops, according to the Journal of Yangtze University (Natural Science Edition).

Neonicotinoids are soluble in water and absorbed systemically by plants, and some are sprayed on urban lawns and landscapes. However, over 80% of synthetic neonicotinoids are applied to seeds prior to planting hundreds of millions of acres of corn, soybean, sunflowers and other crops. In Canada’s Ontario and Quebec provinces, 100% of corn seed is treated with neonicotinoids, said Nadejda Tsvetkov of Toronto’s York University at “Entomology Without Borders.” Though neonicotinoids were seldom found in corn pollen samples, somehow, perhaps by water transport, neonicotinoids are finding their way into clover and willow tree pollen far from corn fields.

“For a lot of farmers it is hard to get seeds untreated, especially corn,” as commercial seed is routinely treated with neonicotinoids regardless of need, said the University of Maryland’s Aditi Dubey at “Entomology Without Borders. In Maryland and other mid-Atlantic USA states where low pest pressures are the norm, neonicotinoid seed treatments are both unneeded and counterproductive. In 3-year Maryland rotations with double-cropped soybeans, winter wheat and corn, sowing seeds treated with thiamethoxam or imidacloprid reduced beneficial predatory ground beetles and increased slug damage to crops. Mid-Atlantic USA farmers typically apply 4 unnecessary prophylactic seed treatments every 3 years. Besides reduced biocontrol and more pest damage, soil accumulation over time is a disturbing agro-ecosystem possibility.

Alternative seed treatments include natural plant hormones such as salicylic acid and methyl jasmonate, which induce a natural immunity called induced systemic acquired resistance (SAR). Crops such as lettuce and argula (rocket) grown from seed treated with salicylic acid and methyl jasmonate also release volatile gases repelling pests such as sweet potato whitefly, a major worldwide pest, said Ben-Gurion University’s Mengqi Zhang at “Entomology Without Borders,” a gathering of 6,682 delegates from 102 countries. Numerous botanical materials and microbes have also been investigated around the world as alternative seed treatments.

A proactive approach to honey bee and bumble bee health includes a diversified landscape sown with herbs and medicinal botanicals for self-medication, not just natural nicotine from tobacco nectar or other sources. Thymol, an essential oil found in thyme and many other plants, is already sprayed in hives by beekeepers to combat Varroa mites. At “Entomology Without Borders,” North Carolina State University’s Rebecca Irwin reported laboratory choice tests where bumble bees rejected nicotine. In field tests, bumble bees were given a choice of different colored flowers each with a different botanical such as thymol, nicotine, anabasine and caffeine. Bumble bees only selected flowers with thymol to self-medicate. Interestingly, thymol and other herbal essential oils also synergize nicotine, boosting effectiveness against disease pathogens and perhaps also minimizing the likelihood of colony collapse.

Landscapes and hedgerows sown with medicinal plants such as thyme, sunflower and foxglove minimize bumble bee disease transmission, said Lynn Adler of the University of Massachusetts, Amherst. The current USA farm bill will actually pay farmers to plant bee-friendly sunflower edges or hedgerows around canola fields. Antimicrobial and medicinal honeys derived from sunflower, bay laurel (Laurus nobilis), black locust, etc., also effectively combat bee diseases like chalkbrood and foulbrood, said Silvio Erler of Martin-Luther-Universität in Halle, Germany at “Entomology Without Borders.”

Bee pharmacology is also useful in human medicine. In Oaxaca, Mexico gangrene is stopped and wounds are healed by combining maggot therapy and honey, reported Alicia Munoz. Maggot therapy uses sterilized (germ-free) green bottle fly maggots to disinfect and cleanse wounds by eating unhealthy tissues and secreting antibiotics, allowing healthy pink tissue to grow back under honey-soaked gauze. This cost-effective approach reduces hospital stays, lowers morbidity and can eliminate the need for surgery. It may sound yucky, but for diabetics and patients with bed sores or wounds where surgery is medically impossible, a few maggots and a little honey is preferable to amputating wounded or infected limbs.

Cancer-fighting bee propolis products were touched upon at “Entomology Without Borders” by Chanpen Chanchao of Chulalongkorn University in Bangkok, Thailand, where hives of stingless bees are reared like conventional honey bees. Cardol, a major component of propolis from the Indonesian stingless bee, Trigona incisa, causes early cancer cell death by disrupting mitochondrial membranes and “producing intracellular reactive oxygen species (ROS).” ROS are essential to energy, immunity, detoxification, chemical signaling, fighting chronic and degenerative diseases, etc. Cardol “had a strong antiproliferative activity against SW620 colorectal adenocarcinoma,” killing colon cancer cells within 2 hours, followed by complete cell necrosis within 24 hours. Thus, cardol is an “alternative antiproliferative agent against colon cancer.”

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Pigments of the Imagination: Cochineal’s Renaissance

June 22, 2016

SAP-SUCKING SCALE INSECTS, such as cochineal, kermes and lac, are sometimes sprayed with pesticides as landscape and crop pests, and other times cultivated as beneficial insects. For example, cochineal secals have provided biological weed control in India, Australia and South Africa where imported prickly pear cactus (Opuntia spp.) hedges have escaped and become rangeland weeds. Cochineal scale insects, bred in ancient Mexico to yield 15%-30% color pigment content, have been grown in the Americas for many centuries on prickly pear cactus as a sustainable, biodegradable colorant crop yielding dyes ranging from red, yellow, orange and brown to pink, lavender and purple (depending on mordant, pH, etc.). Intensely red cochineal has a long and famous history in painter’s palettes, tapestry and fabrics, and has been used for centuries to color or stain tissues red or purple for microscope visibility in biology and microbiology labs, medicine and dentistry. Cochineal scale pigments also color selected beverages, foods (on labels as E-120 & carmine) and cosmetics like lipstick, rouge and nail polish. Biochemistry labs like the cochineal red molecule’s ability to bind or bond with proteins, nucleic acids and fats (lipids). Analytic chemists use cochineal “for photometric determination of boron, beryllium, uranium, thorium, and osmium.” At the cutting edge frontier of science, cochineal pigments are being adapted to “molecular information processing” and computing. The red pigment’s “strong photosensitization and photocurrent switching effects” are being designed into next generation optoelectronic (i.e. light, photon) devices like semiconductors, fuel cells, sensors and photovoltaic solar energy systems.

“In Latin-the indispensable language of Renaissance medical professionals—the word pigmentum signified both a pigment and a drug,” writes Amy Butler Greenfield on page 83 of the paperback edition of her meticulously researched book, A Perfect Red, which follows the parallel rise and fall of the Spanish Empire and the secretive cochineal red export trade. “Artists who made their own paints were often advised to procure cochineal from their local “Drugist” or pharmacy, advice that highlights the fact that Europeans also used cochineal as a medicine,” a practice “at least partly borrowed from ancient Mexico,” where cochineal was used to clean teeth and also dissolved in vinegar and applied as a poultice to cure wounds and strengthen bodily organs. Spain profited more from importing cochineal into Europe than from all its plundered and mined New World gold. When ancient alchemy’s metamorphosis into modern chemistry advanced to synthesizing a less expensive, wider range of brighter dye pigments, the Spanish red dye monopoly was obsoleted and the financial collapse of the steadily weakening empire allowed for a global power shift; the USA, fresh from coast to coast expansion and hot for global colonial-style conquests, easily knocked off the remnant hollow shell of the Spanish Armada in the Caribbean and Philippines in 1898.

Let’s start with cochineal and scale insects as pests, and organic control alternatives, as that is how most people encounter and view scale insects. Parasitoid wasps, lady beetles, birds and many other natural enemies provide biological control of scale insects, but not always enough at the right time. Highly refined petroleum oils, vegetable oils and high-pressure water sprays (with or without soap or surfactants) are among the often used remedies. High pressure water sprays, from a nozzle or heavy overhead rainfall, wash off or injure cochineal scales; and this remedy is sometimes used post-harvest by packing houses to clean fruit prior to shipping. Laboratory studies indicate that epazote (Chenopodium ambrosioides), mint (Mentha spp.) and marigold (Tagetes spp.) extracts applied with emulsifiers are potential organic or environmentally friendly synthetic pesticide alternatives.

At the Entomological Society of America (ESA) annual meeting in Minneapolis I talked with Colorado State University extension entomologist Whitney Cranshaw, whose special spiked shoes for killing white grub beetle larvae beneath the soil surface while walking golf course turf and lawns achieved notoriety in Smithsonian magazine many moons ago. This time he was a lonely entomologist, as out of hundreds of passersby no one was stopping at the poster of graduate student Rachael Sitz reporting on a kermes scale vectoring a bacteria causing drippy blight of red oaks in Colorado. Cranshaw was ecstatic having a customer, and figured I was studying the poster display because the kermes scale was also found in California locales such as San Jose, Mammoth Lakes and Monticello Dam on blue oaks and chinquapin bushes. Actually, I was wondering if this particular kermes scale, which went by the scientific name Allokermes rattani, was related to Old World kermes scales used for centuries by pigment artists in Europe and Asia. According to Cranshaw, workers handling the Colorado kermes scale came away with hands dyed a deep brown. So, perhaps this “pest” scale insect is indeed an untapped resource, similar to cochineal, waiting to be discovered by textile artists, painters and photographers looking for natural organic pigments.

My own interest in these insect pigments is a bit abstract, how to incorporate these pigments into the photographic printing process, inspired in part by viewing Robert Rauschenberg’s vegetable pigment prints with photo images from Indonesia. Cochineal was apparently on occasion used in early color photography printing, dating back to the 1800s and heliochromes, which I surmise are solar prints that also use silver as a light-sensitive pigment. Some modern authors talk of a “green synthesis,” fusing conventional silver nanoparticle photography with cochineal red pigments; but I have not found much on the subject. “Color photography,” U.S. Patent No. 923,019 from 25 May 1909 reads: “To all whom it may concern: Be it known that I, EDGAR CLIFTON, a subject of His Majesty the King of the United Kingdom of Great Britain and Ireland, residing at 3 BeaufortVillas, London Road, Enfield, in the county of Middlesex, England, have invented certain new and useful Improvements in Color Photography…known as the two color process; the three color process; and the four plate process…so that the assemblage gives more or less natural color effects…As the red dye: alizarin (with alumed reliefs), cochineal red (or carmin with ammonia), or magdala red…”

SCALING UP PRODUCTION of pigment scales, versus natural harvest, is often surprisingly difficult. For one thing, about 14,000 individual scale insects are needed to obtain 100 grams of raw cochineal pigment. Far from being dumb savages, ancient Mexico’s New World cochineal growers were superb insect breeders. The best cochineal “breeds” contain 18%-30% pigment by dry weight. Spaniards settling in the New World never mastered the delicate art of cultivating cochineal scale on prickly pear cactus, and instead relied on the indigenous los indios de Mexico, some of whom grew rich on the cochineal trade in what was essentially a free market. Many Spanish colonists found it intolerable that the natives were becoming the richest citizens, and this led to all kinds of frictions and conflicts aimed at turning the natives into poorer, more docile (less uppity) and easier to control colonial subjects. The Spanish were remarkably successful at keeping curious outsiders out of the cochineal production areas for centuries, making the cochineal red dye one of the world’s all-time best kept trade secrets. Most Europeans assumed the grana or granules of cochineal were seeds or plant material, like indigo or madder. On those rare occasions when the secret was revealed, the public refused to believe that cochineal red was literally dried insects. This combination of secrecy and worldwide ignorance allowed the Spanish cochineal monopoly to persist for several centuries and be more lucrative than precious metals.

As any entomology grad student can tell you, the same insect that is an abundant pest can often be impossibly hard to grow when you want it for experiments or as a thesis subject. For one thing, the “insect crop” usually has its own set of pests (called natural enemies), which for cochineal scales includes bacteria, lady beetles, syrphid or hover flies, predatory caterpillars, rodents, reptiles and birds. To prevent “crop failure,” cochineal scales need pampering and protection: 1) from natural enemies; 2) shade to protect from direct sunlight; 3) shelter from heavy rains that wash off and injure the scales. Raising cochineal scales as “farm animals” or “livestock” on prickly pear cactus was often a family enterprise in Old Mexico, an art or skill passed down from generation to generation. The prickly pear cactus itself is still also food, animal fodder and medicine in Mexico. But cochineal grana are no longer treated like money or currency, as it was in Aztec Mexico when cochineal was used in payment of tribute or taxes. In that sense, in contrast to a modern dollar, euro, yen, peso, pound, rupee or digital currency, which cannot be directly used as dyes or medicines, the grana possessed an exquisite versatility and flexibility in ancient times.

CARMINIC ACID, a MEDICINAL CHEMICAL pigment compound extracted from cochineal and first synthesized in 1998, belongs to a class of anti-tumor and antibiotic compounds called anthracycline derivatives, which “are believed to develop their cytotoxic effect by penetrating into the tumor cell nucleus and interacting there with DNA,” write chemists at Gazi University in Ankara, Turkey. Combined with other compounds, cochineal is also active against viruses and other microbes. In Tamil Nadu, India cochineal scale insects collected from cacti are crushed, boiled in water and dried to a powder used against whooping cough and as a sedative. Other traditional uses likely abound.

In nature, cochineal functions as an insect repellent. One theory is that cochineal repels ants, protecting young scale insects before their protective waxy outer covering forms. A carnivorous caterpillar eating the scales incorporates the cochineal dye into its own bodily defenses. A study in the Journal of Polymer Science concluded that cochineal and other natural dyes (madder, walnut, chestnut, fustic, logwood) and mordants (aluminum, chrome, copper, iron, and tin) increased the insect resistance of the wool fabric to attack by black carpet beetles.” Indigo was least effective, and cochineal and madder were most effective except when used with tin and chrome as the mordant or binding agent. I only remember one ESA presentation investigating cochineal as a natural insecticide, and that was back in 2004; the idea was that since carminic acid was already approved as safe for food by the FDA, cochineal could be formulated as an organic bait spray to stop fruit flies without losing organic certification. The researcher theorized that cochineal needs sunlight to be activated as an insecticide, and would thus be ideal for organic agriculture. But as far as I know, the idea was never adapted as an agricultural or quarantine practice.

COMBINING COLOR and HEALING is, however, an idea gaining traction. Carminic acid, a brilliant red compound constituting about 10% of cochineal8, “is one of the most light and heat stable of all the colorants and is more stable than many synthetic food colors,” write Khadijah Kashkar and Heba Mansour in the Department of Fashion Design at King Abdul Aziz University, Saudi Arabia. “Besides the color attributes, recently, also has been reported to beneficial to health with potential antibiotic and antitumor properties. At the beginning of the 21st century it is predicted that many colors will be used for both their additional beneficial functions in the body, as well as, coloring effect.” Whether color and healing were also linked in ancient or Aztec times with cochineal is an intriguing question. Perhaps everything old is indeed new again, but who knows what the ancient New World healers or shaman thought when applying bright red or purple cochineal poultices.

PREVENTIVE MEDICINE might be what to call the combination of organic cotton and natural cochineal dyes to block ultraviolet light from skin contact. Ajoy Sarkar of Colorado State University, writing in the journal BMC dermatology: “The ultraviolet radiation (UVR) band consists of three regions: UV-A (320 to 400 nm), UV-B (290 to 320 nm), and UV-C (200 to 290 nm). UV-C is totally absorbed by the atmosphere and does not reach the earth. UV-A causes little visible reaction on the skin but has been shown to decrease the immunological response of skin cells. UV-B is most responsible for the development of skin cancers…Other than drastically reducing exposure to the sun, the most frequently recommended form of UV protection is the use of sunscreens, hats, and proper selection of clothing. Unfortunately, one cannot hold up a textile material to sunlight and determine how susceptible a textile is to UV rays.” Heavy concentrations of synthetic dyes in synthetic fabrics generally provide good UVR protection, but are not as comfortable as cotton fabrics for warm, humid climates. Generally, the darker the color and the thicker the weave or denser the fabric, the better to protect against UVR. Depending upon the weave (e.g. twill vs sateen), Sarkar reported good to excellent UVR protection with natural dyes such as madder, indigo and cochineal.

COCHINEAL’S 21ST CENTURY RENAISSANCE and resurgence includes harnessing cochineal’s ability to capture (harvest) or route light (photons) and electrons in advanced or next generation optoelectronic devices such as semiconductors, light harvesting antennae, sensors, fuel and solar cells, and molecular information and logic gates for computing devices. I was surprised to learn that natural pigments have a long history in advanced electronics: “As early as the birth stage of lasers, coumarin, which is found naturally in high concentration in the tonka bean (Dipteryx odorata), was used in dye lasers” and “coumarin dye is still the basic active medium for many tunable dye laser sources,” writes M. Maaza (2014) of the University of South Africa. “Extracts from Hibiscus sabdariffa, commonly known as Roselle, carminic acid of the cochineal scale and saffron exhibit exceptional nonlinear optical (NLO) properties of a prime importance in optics.”

THE “NEXT GENERATION” SOLAR CELL replacement for today’s silicon-based solar cells will probably be a dye-sensitized solar cell (DSSC) based on titanium dioxide (TiO2), a semiconductor material that is fused with color pigments analogous to those used in conventional color photography (e.g. silver halide emulsions sensitized by dyes). TiO2 and other metal oxides are widely used in medicine, food preservation, cosmetics, sunscreens, paints, inks and a wide range of electronic devices for sensing, imaging, optics, etc. TiO2 is relatively inexpensive, and deemed low toxicity. Interestingly, TiO2 nanoparticles for solar cells can be produced from cultures of bacterial cells, such as the Lactobacillus sp. found in yogurt or curd, which means an even “greener” solar cell fabrication process.

The scientific roots of the modern solar cell go back to French physicist Edmond Becquel’s discovery of the photovoltaic effect in 1839; and prototype solar cells with efficiencies of 1% or less also date back to the 1800s. Though Albert Einstein explained the photovoltaic effect in 1904, the development of lightweight solar energy cells to power spacecraft in the 1950s. But the DSSC or Grätzel cell is a 1990s’ innovation attributed to Mr. O’Regan and Michael Grätzel. “This new device was based on the use of semiconductor films consisting of nanometer-sized TiO2 particles, together with newly developed charge-transfer dyes,” and had “an astonishing efficiency of more than 7%,” write Agnes Mbonyiryivuze et al. (2015) in the journal Physics and Materials Chemistry.

Next generation DSSCs or photovoltaic cells are currently undergoing a major design transition using natural color pigments like those found in cochineal scale insects. DSSCs with efficiencies in the 10% to 15% range can be manufactured with titanium dioxide (TiO2) nanoparticles bonded on a thin film with a light-sensitive dye utilizing a rare and expensive platinum group heavy metal, ruthenium (Ru; named after Russia). Ruthenium’s relatively high cost and environmental and toxicology concerns are a barrier to commercialization that is spurring the search for substitutes; namely cheaper and more environmentally friendly natural pigment. Companies working “to bring DSSC technology ‘from the lab to the fab’” include “Dyesol, G24i, Sony, Sharp, and Toyota, among others,” write Mbonyiryivuze et al. (2015). “Functional cells sensitized with berry juice can be assembled by children within fifteen minutes, the large choice of colors, the option of transparency and mechanical flexibility, and the parallels to natural photosynthesis all contribute to the widespread fascination. In 2013, the drastic improvement in the performance of DSSC has been made by Professor Michael Grätzel and co-workers at the Swiss Federal Institute of Technology (EPFL). They have developed a state solid version of DSSC called perovskite-sensitized solar cells that is fabricated by a sequential deposition leading to the high performance of the DSSC. This deposition raised their efficiency up to a record 15% without sacrificing stability…this will open a new era…even surpass today’s best thin-film photovoltaic devices.”

“PIGMENTS MAKE NATURE COLORFUL and LIKABLE,” writes Chunxian Chen, a researcher at the University of Florida’s Citrus Research and Education Center and the editor of a 277-page book published by Springer in 2015, Pigments in Fruits and Vegetables: Genomics and Dietetics, which places a heavy emphasis on the nutritional and medicinal benefits of colorful natural pigments like those coloring crops of carrots and sweet potatoes orange and radishes and tomatoes red. “Plant pigments usually refer to four major well-known classes: chlorophylls, carotenoids, flavonoids, and betalains…Chlorophylls are the primary green pigments for photosynthesis. The latter three are complementary nongreen pigments with diverse functions…The importance of colors in living organisms cannot be overstated…they are biosynthesized behind the scenes in living organisms and ultimately ingested in daily diet.” Presumably this daily consumption and medicinal benefits makes natural pigments in general logical and sustainable alternatives to expensive heavy metals in “green” electronic, computer and solar energy cell designs.

Agnes Mbonyiryivuze, in her 2014 dissertation titled “Indigenous natural dyes for Gratzel solar cells: sepia melanin,” provides a readable overview of solar energy cells utilizing natural pigments. The list of natural pigments fabricated into solar cells is long, and the sources range from cochineal scale insects, green algae, baker’s yeast, fungi and bacteria to bougainvillea flowers, Chinese medicinal plants (e.g. tea, pomegranate leaves, wormwood, mulberry fruit) and food crops like beets, parsnip, purple cabbage, blackberry and black grapes. The black pigments are of particular interest, including skin melanins providing UV protection and the black powder from cuttlefish (Sepia officinalis) ink sacks. “To maximize the absorption of more photons from the sun light for DSSC,” writes Mbonyiryivuze, “it is better to have a black dye sensitizer having extremely high broadband absorption. It should absorb not only in visible range but also in ultraviolet and near-infrared regions. This challenge can be handled by using natural dyes from other sources such as fauna from which sepia melanin was obtained. Melanins are well-known natural pigments used for the photoprotective role as a skin protector because of their strong UV absorbance and antioxidant properties. Melanin possesses a broad band absorbance in UV and visible range up to infrared.” Sepia melanin “can also conduct electricity and is thus considered a semiconductor material.”

“There are numerous trials of solar cell construction which are based on biomolecules and supramolecular systems, for instance, chlorophylls, porphyrins, phtalocyanines, and other natural or bioinspired dyes,” write researchers in Poland constructing double layer solar cells with cochineal red and gardenia yellow pigments bonded to TiO2 nano-surfaces. “Hybrid materials incorporating biomolecules immobilized on conducting or semiconducting surfaces are unique systems combining collective properties of solids with structural diversity of molecules, which besides photosensitization show other unique electrochemical and catalytical properties.”

According to Mousavi-Kamazani et al. in Material Letters (2015), quantum dots composed of cochineal and copper offer the economically attractive “possibility of single step production of three-layered solar cells.” Clearly, though the distance might be measured in years or decades, we are getting closer to a cochineal and natural pigment renaissance that transcends traditional fabric dyes and artist’s pigments and extends into medicine and the heart of modern computers, lasers and electronic and optical devices of all sorts.


Food Sweetener Safely Slays Insects

August 27, 2015

CERTAIN SUGARS CONSIDERED SAFE as sweeteners in the human food supply can double as environmentally-friendly pest remedies, and even make biological control of insects by beneficial fungi more practical for households, farms and gardens. Considering that caffeine from coffee grounds can be used against deadly dengue mosquitoes and that a variety of traditional herbs can blast away bed bugs, insecticidal sugar compounds should come as no surprise. Perhaps the only remedy more surprising is that rain water or simulated rain sprays from hoses or irrigation equipment can safely wash away pests with no toxic pesticide residues to worry about in the environment.

Using sugars directly to slay insects is somewhat unusual. However, sugars are commonly used as attractants, for instance to lure fruit flies, moths or ants to baits and traps both for population control and as a survey method or monitoring tool. California citrus growers have a long history of using sugar sprays as an IPM (integrated pest management) strategy to lure fruit-scarring citrus thrips to organic or botanical formulations of ryania (“from woody stem and root materials of plants of the genus Ryania”) or sabadilla (alkaloids from seeds of a lily bulb, Schoenocaulon officinale). “INTEGRATED PEST MANAGEMENT implies that techniques used to manage one pest species should not disrupt techniques used to manage other pests of the same crop,” wrote J.D. Hare and Joseph Morse in the Journal of Economic Entomology. “In citrus pest management in California, this situation is well illustrated in the choice of pesticides for the management of one major pest, citrus thrips, Scirtothrips citri (Moulton), without disruption of several effective biological control agents of the other major pest, California red scale, Aonidiella aurantii (Maskell).”

That sugars can be lethal to pests and be a source of environmentally-friendly pesticides is not exactly intuitive. “Potential of the non-nutritive sweet alcohol erythritol as a human-safe insecticide” was the strangely intriguing title of Drexel University’s Sean O’Donnell’s presentation at the Entomological Society of America (ESA) annual meeting. Many of the details were previously published in PLoS ONE, an open access journal, and in part because of the origins of the research in a grade school science project by one of the researcher’s sons, aspects of the story have been widely reported in various media. “Erythritol is a zero-calorie sweetener found in fruits and fermented foods,” summarized Lauren Wolf in Chemical & Engineering News, and “is Generally Recognized As Safe by the Food & Drug Administration and has been approved as a food additive around the globe.”

“Many pesticides in current use are synthetic molecules such as organochlorine and organophosphate compounds,” and “suffer drawbacks including high production costs, concern over environmental sustainability, harmful effects on human health, targeting non-intended insect species, and the evolution of resistance among insect populations,” write the researchers in PLoS ONE. “Erythritol, a non-nutritive sugar alcohol, was toxic to the fruit fly Drosophila melanogaster. Ingested erythritol decreased fruit fly longevity in a dose-dependent manner, and erythritol was ingested by flies that had free access to control (sucrose) foods in choice and CAFE (capillary feeding assays) studies…

“We initially compared the effects of adding five different non-nutritive sugar substitutes (Truvia, Equal, Splenda, Sweet’N Low, and PureVia,” wrote the researchers in PLoS ONE. “Adult flies raised on food containing Truvia showed a significant reduction in longevity…We noted that adult flies raised on food containing Truvia displayed aberrant motor control prior to death. We therefore assayed motor reflex behavior through climbing assays…Taken together with our longevity studies, these data suggested some component of the non-nutritive sweetener Truvia was toxic to adult Drosophila melanogster, affecting both motor function and longevity of this insect…

“Our initial analysis of sweeteners included two sweeteners that contained extracts from the stevia plant, Truvia and Purevia. While adult flies raised on food containing Truvia showed a significant decrease in longevity compared to controls, this was not the case for flies raised on Purevia. These data suggest stevia plant extract was not the toxic element in these sweeteners. Purevia contains dextrose as a bulk component, while Truvia contains erythritol as a bulk component…To determine if erythritol was the toxic component of Truvia, we repeated our longevity studies on food containing equal weight/volume (0.0952 g/ml) of nutritive sugar control sucrose, and non-nutritive sweeteners Truvia, Purevia, and erythritol. We assured the flies were successfully eating the foods containing these sweeteners through dye labelling the food with a non-absorbed blue dye (blue food), and visual confirmation of blue food present in fly abdomens and proboscises daily…The average percentage of blue abdomens throughout the study were 97.46%.”

“These data confirm all treatment foods (including Truvia and erythritol treatments) were consumed by adult flies, and suggest mortality was not due to food avoidance and starvation…A large body of literature has shown that erythritol consumption by humans is very well tolerated, and, indeed, large amounts of both erythritol and Truvia are being consumed by humans every day throughout the world. Taken together, our data set the stage for investigating this compound as a novel, effective, and human safe approach for insect pest control. We suggest targeted bait presentations to fruit crop and urban insect pests are particularly promising.”

Interestingly, a few decades ago UK researchers found that the sweeteners (sugar alcohols; polyols) erythritol, glycerol and trehalose rendered more effective several insect biocontrol fungi, Beauveria bassiana, Metarhizium anisopliae and Paecilomyces farinosus. These insect-killing fungi need a relative humidity (RH) near 100% for germination of their conidia (seed-like propagules). “Conidia with higher intracellular concentrations of glycerol and erythritol germinated both more quickly and at lower water activity,” wrote UK researchers J.E. Hallsworth and N. Magan in the journal Microbiology. “This study shows for the first time that manipulating polyol content can extend the range of water availability over which fungal propagules can germinate. Physiological manipulation of conidia may improve biological control of insect pests in the field…Although fungal pathogens have been used to control insect pests for more than 100 years, pest control has been inadequate because high water availability is required for fungal germination.”

Curiously, erythritol and glycerol, besides being sweetening substances, also function as antifreeze compounds. Certain Antarctic midges, known as extremeophiles for living in an ultra-cold habitat, ingest and sequester erythritol from their food plants; and as antifreeze it protects the adult flies from freezing. Indeed, many mysteries remain. Besides being found in green plants like stevia and in lower amounts in fruits, erythritol is found in certain mushrooms, lichens and algae. Human and animal blood and tissues apparently have low endogenous levels of erythritol; and erythritol is a yeast fermentation product (hence in sake, beer, wine). In human medicine, erythritol has been used for coronary vasodilation and treating hypertension; and according to Japanese microbiologists, erythritol ingestion may mean fewer dental cavities (caries) than sucrose sugar.


Grapes Love Tobacco & Sage

June 13, 2015

GRAPE VINES GAIN and pests suffer when TOBACCO and SAGEBRUSH grow in the same neighborhood. For example, Chinese experiments show that when tobacco roots intermingle with grape roots, vineyards soils are progressively cleansed of the dreaded soil-dwelling phylloxera aphid; the same phylloxera aphid that almost completely destroyed French grape growing in the 1800s, before resistant rootstocks were discovered. In recent decades, the phylloxera aphid has evolved new forms that destroy formerly-resistant rootstocks. But on the positive side, the phylloxera plague in nineteenth century French vineyards was a major catalyst for innovations such as the development of modern scientific agriculture and modern methods for fumigating or disinfesting sick soils.

Tobacco plants get a bad rap today, as the source of abused and addictive products with adverse health effects. But it was not always so, and need not be so today, write David A. Danehower and colleagues in the book, Biologically Active Natural Products: Agrochemicals: “When Columbus first arrived on the shores of North America, he found Native Americans growing and using a plant unknown to Europeans. This plant held great spiritual significance to Native Americans. Scientists who followed in the footsteps of the early North American explorers would later name this plant tobacco. Tobacco (Nicotiana tabacum) farming began in the early 1600s near the Jamestown colony in Virginia. As the use of tobacco products for smoking, chewing, and snuff was promoted in Europe, tobacco became a leading item of commerce between the colonies and England. Notably, George Washington and Thomas Jefferson both farmed tobacco. Thus, the history of America is inextricably linked with the history of tobacco production.”

The specific idea of interplanting tobacco with grapevines to control soil pests like phylloxera aphids is apparently a recent Chinese agricultural innovation. Why no one thought of it before is a mystery, as nicotine from tobacco plants has a long history as a fumigant and sprayed insecticide; and more recently sweet “sugar esters” (fructose, glucose, fatty acids) have been singled out from among the several thousand chemical compounds in tobacco as “new” natural insecticides (some fungi and other microbes are also killed). Perhaps agricultural tradition plays a role, as the Chinese have an ancient agricultural heritage that includes pioneering biological pest control (e.g. predatory ants to control citrus orchard pests) and routinely interplanting compatible plants for their pest-fighting and mutually beneficial effects. Of course, growing cover crops and beneficial insect plants like sweet alyssum in grape rows is becoming more common. And since ancient times, the Mediterranean areas of Europe and the Middle East have had grape vineyards interspersed with oaks (corks, barrels for wine grapes), olive trees and crops such as wheat. But never before has tobacco been grown among grape vines to control soil pests. Indeed, modern farmers seem to favor pumping liquid chemicals and volatile gases into the soil to combat soil pests.

Perhaps as close as a nineteenth century French grape grower came was Bernardin Casanova of Corsica, France, who in 1881 patented a liquid mixture of grape distillates, Corsican tobacco, spurge, laurel, grain straw, burnt cork and soap that was rubbed and poured on the base of grapevines to kill phylloxera. In California, which has native plants that are every bit as insecticidal as nicotine from tobacco, the only anti-phylloxera interplanting seems to have been new resistant rootstocks to eventually take the place of the old. In essence, a concession of failure and a starting over with new rootstock (and pulling out the old phylloxera-infested vines).

Like Mr. Casanova in nineteenth century France, the modern Chinese researchers started out with a watery solution containing tobacco; but in a bit more scientific fashion with controlled tests of the tobacco solution on young greenhouse-grown grape vines. “The results showed that aqueous extracts of tobacco had certain alleviating effects on phylloxera infection,” according to a 2014 abstract from the journal Acta Entomologica Sinica. “Both the aqueous extracts of tobacco at the concentration of 20 mg/mL and 50 mg/mL had an inhibition to phylloxera infection,” with a 50% reduction in phylloxera infection within 3 weeks (along with a reduction of fungal invaders that kill injured grape roots).

Chinese tobacco-grape laboratory and field studies were also reported in the Journal of Integrative Agriculture in 2014. The lab studies indicated that tobacco extracts in water were indeed a valid herbal (botanical) remedy against phylloxera aphids. In three years of field tests with tobacco interplanted in infested grape vineyards, phylloxera infestations of grape roots steadily decreased each year. “Tobacco was used as the intercropping crop because it includes nicotine, which is a source of bio-insecticides,” said the researchers. “The production of new grape roots was significantly higher in the intercropping patterns than in the grape monoculture in 2010, 2011 and 2012, and the vines gradually renewed due to the continuous intercropping with tobacco over three years…The results indicated that the secondary metabolites of tobacco roots had released to soil and got to the target pest.” Tobacco intercropping effects on grape plants was also measurable in terms of “cluster number per plant, cluster weight, cluster length, cluster width, berry number per cluster, mean berry diameter in the mid portions of the cluster, carbohydrate content, fruit color index, leaf width and branch diameter.” The researchers expect that this “Successful intercropping with tobacco” will stimulate more research with other insecticidal plants to disinfest vineyard soils.

We could probably end the blog item here, or have a second article as part II, but we have some interesting interactions among sagebrush and tobacco plants that can spillover to grape vineyards. Oddly enough, sagebrush and tobacco seem to get along very well. According to M.E. Maffei, writing in the South African Journal of Botany: “Aerial interaction of the wild tobacco (Nicotiana attenuata) and sagebrush (Artemisia tridentata subsp.) is the best-documented example of between-plant signaling via above-ground VOCs (Volatile Organic Compounds) in nature.” Wounded or “Clipped sagebrush emits many volatiles, including methyl jasmonate, methacrolein, terpenoids, and green leaf volatiles.” These sagebrush volatiles (VOCs) stimulate nearby tobacco plants to become less hospitable to caterpillar pests (fewer in number). The process is called priming and results in plants producing more chemicals deleterious to pests. For readers desiring all the details and more theory: In 2006, Kessler et al. published in a journal called Oecologia under the title “Priming of plant defense responses in nature by airborne signaling between Artemisia tridentata and Nicotiana attenuata.”

Big Sagebrush, known scientifically as Artemisia tridentata, is a native North American plant that can reach 4 meters in height and live from 30 to over 200 years in arid desert environments by using hydraulic lift to pump water from deep soil layers. The plants are a rich and underutilized source of medicinal compounds, insecticides, fungicides, natural preservatives, etc. Worldwide there are at least 500 Artemisia sagebrush species, many used in traditional medicines (e.g. China), cosmetics, insect repellents, and as spices and flavorings in foods. For example, Artemisia annua has attracted attention to combat malaria. Readers desiring a crash course in Artemisia species and their bio-active essential oils will find it online in an excellent 24-page review article in a journal called Molecules.

Big Sagebrush is “found in arid regions of North America from steppe to subalpine zones, dry shrub lands, foothills, rocky outcrops, scablands, and valleys,” wrote Christina Turi and colleagues in 2014 in the journal Plant Signaling & Behavior. “Traditionally, species of Big Sagebrush have been used as a ceremonial medicine to treat headaches or protect individuals from metaphysical forces. A total of 220 phytochemicals have been described in A. tridentata and related species in the Tridentatae. Recently, the neurologically active compounds melatonin (MEL), serotonin (5HT), and acetylcholine (Ach) were identified and quantified.” In other words, sagebrush plants and human brains and nervous systems have a lot in common.

Indeed, galanthamine, a botanical drug treatment for mild to moderate Alzheimer disease, can also be used to “treat” sagebrush. Galanthamine, which is named after the snowdrop plants (Galanthus species) where it was discovered, is also found in Narcissus and other common bulbs. Galanthamine is, according to researchers Turi et al., “a naturally occurring acetylcholinesterase (AchE) inhibitor that has been well established as a drug for treatment of mild to moderate Alzheimer disease.” Why bulb plants produce chemicals affecting both Alzheimer disease (human nervous systems) and sagebrush plants is a good question. One theory is that plants release these chemicals into the environment to communicate with and influence the behavior of other plants, and also perhaps deter or otherwise influence herbivorous animals. Environmentalists, overly preoccupied with worries about carbon dioxide and GMOs, might ponder the fact that human chemicals with medicinal effects released into the environment might be the bigger threat, affecting plants and ecosystems in ways not yet fully appreciated that may comeback to bite us.

The Western USA is known for its vast expanses, perhaps 50 million acres with Big Sagebrush, some of which is being displaced for vineyards in isolated valleys in the Pacific Northwest. I particularly like the description of the Big Sagebrush ecosystem at the Sage Grouse Initiative: “To many of us, sagebrush country symbolizes the wild, wide-open spaces of the West, populated by scattered herds of cattle and sheep, a few pronghorn antelope, and a loose-knit community of rugged ranchers. When you stand in the midst of the arid western range, dusty gray-green sagebrush stretches to the horizon in a boundless, tranquil sea. Your first impression may be of sameness and lifelessness—a monotony of low shrubs, the over-reaching sky, a scattering of little brown birds darting away through the brush, and that heady, ever-present sage perfume.”

About 90% of the native sagebrush steppe habitat in the eastern Washington grape growing area was removed to make way for the vineyards. But the 10% remaining sagebrush habitat may have important ecological benefits, such as improved natural or biological pest control in the vineyards. One suggestion is to leave some of the native Big Sagebrush around vineyards, for its beneficial ecological effects. “Perennial crop systems such as wine grapes have begun using cover crops and hedgerows to increase beneficial insects and promote sustainable vineyard management in areas like New Zealand and California,” Washington State University researcher Katherine Buckley told the 2014 Entomological Society of America (ESA) annual meeting in Portland, Oregon. “However, in arid wine growing regions such as eastern Washington, cover crops are often prohibitively expensive due to water costs. We wanted to determine if native plants, which require little or no irrigation, could be used to increase beneficial insects and enhance conservation biological control of vineyard pests in eastern Washington.”

The native sagebrush steppe ecosystem has a wide range of plants, but is characterized by species such as big sagebrush (Artemisia tridentata), rabbitbrush (e.g. Chrysothamnus, Ericameria spp.), bitterbrush (Purshia spp.) and perennial bunchgrasses (e.g. Agropyron, Stipa, Festuca, Koeleria, Poa spp.). The Big Sagebrush ecosystem is richer in species than meets the eye at first glance. Over 100 species of birds (e.g. sage grouse, sage thrasher, sage sparrow and Brewer’s sparrow) forage and nest in sagebrush communities, and they could provide a lot of insect biocontrol at less cost and with less environmental impact than chemical sprays.

A U.S. Forest Service report called Big Sagebrush a keystone species and “a nursing mother” to “31 species of fungi, 52 species of aphids, 10 species of insects that feed on aphids, 42 species of midges and fruit flies that induce galls, 20 species of insects that parasitize the gall inducers, 6 species of insects that hibernate in big sagebrush galls, 18 species of beetles, 13 species of grasshoppers, 13 species of shield-back katydids, 16 species of thrips, 74 species of spiders, 24 species of lichens, 16 species of paintbrushes, 7 species of owl-clovers, 5 species of bird’s beaks, 3 species of broom rapes, and a host of large and small mammals, birds, and reptiles.”

“After locating vineyards with some form of native habitat restoration in four different growing regions of eastern Washington, yellow sticky traps and leaf samples were used to monitor beneficial and pest insect numbers in the habitat restored vineyards and nearby conventional vineyards over a three year period,” said Buckley. The native plants, which are adapted to the region’s hot summers and cold winters, are home to at least 133 insect species. Native habitat vineyards had fewer pest insect species; and higher populations and a higher diversity of beneficial insects. Anagrus wasps, which are known to parasitize pesky grape leafhoppers, were most abundant in Big Sagebrush. More amazingly, this leafhopper biocontrol wasp was found year-round in Big Sagebrush, even when the plant was not flowering. No other plant, not even the photogenic wild roses planted at the end of vineyard rows and admired by tourists, hosted the tiny leafhopper biocontrol wasp year-round.

Garden herbs such as thyme (Thymus ssp.), mugwort (Artemisia ssp.) and fennel (Foeniculum ssp.) have all been tested in vineyard interrows because they are fungicidal against Botrytis cinerea, a fungus attacking grape clusters, and boost soil micro-nutrients like copper, manganese and zinc. Maybe at some point in time, the Chinese interplantings of tobacco and alternating strips of Big Sagebrush (or other Artemisia species) and garden herbs will all get integrated together with other cover crops and native hedgerows into grape vineyards for a more biological or natural approach to agriculture. With sagebrush and tobacco, we have only scratched the surface of vineyard possibilities.


The Mysteries of Colony Collapse

May 15, 2014

COLONY COLLAPSE DISORDER (CCD) of honey bees is one of the lingering mysteries of early 21st Century science in more ways than one: from its microbial, immune system and genetic components to an amorphous almost Orwellian terminology as imprecise and ambiguous as climate change (a slogan wide enough to encompass warming up, cooling down, and even staying the same temperature while the numbers fluctuate around the mean or average). The ambiguous language says both nothing and everything simultaneously, though underlying CCD is a quest for as yet unknown changes in insect rearing circumstances that will produce non-collapsing honey bee colonies. During the 19th century (1800s), a century marked by worldwide famines in the the old colonial empires and phylloxera-ravaged wine-grape vineyards collapsing in France, a revolution in modern medicine was being birthed in the mysteriously collapsing silkworm colonies. Fortunately for lovers of silk fabrics, fashion and textiles, 19th century silkworm farmers had the services of the real-life scientific Sherlock Holmes of the era, the famous French freelance scientist and sometime entomologist, Louis Pasteur.

Pasteur had a knack for solving applied problems like fermentation (beer, wine, vinegar) and silkworm colony collapse, and then using the results to develop broader theories like germ theory, which taught modern doctors to wash their hands and sterilize their instruments so as to stop spreading the germs that commonly killed their patients. How Pasteur almost single-handedly accomplished so much more than whole scientific institutes seemed able to do in the 20th century was the subject of an illuminating mid-20th century book, Louis Pasteur Free Lance of Science, by French-borne microbiologist Rene Dubos. “Toward the middle of the nineteenth century a mysterious disease began to attack the French silkworm nurseries,” wrote Dubos. “In 1853, silkworm eggs could no longer be produced in France, but had to be imported from Lombardy; then the disease spread to Italy, Spain and Austria. Dealers procuring eggs for the silkworm breeders had to go farther and farther east in an attempt to secure healthy products; but the disease followed them, invading in turn Greece, Turkey, the Caucasus–finally China and even Japan. By 1865, the silkworm industry was near ruin in France, and also, to a lesser degree, in the rest of Western Europe.”

“The first triumphs of microbiology in the control of epidemics came out of the genius and labors of two men, Agostino Bassi and Louis Pasteur, both of whom were untrained in medical or veterinary sciences, and both of whom first approached the problems of pathology by studying the diseases of silkworms,” wrote Dubos, who between World Wars I and II worked at the League of Nations’ Bureau of Agricultural Intelligence and Plant Diseases as an editor of the International Review of the Science and Practice of Agriculture. “A disease known as mal del segno was then causing extensive damage to the silkworm industry in Lombardy. Bassi demonstrated that the disease was infectious and could be transmitted by inoculation, by contact, and by infected food. He traced it to a parasitic fungus, called after him Botrytis bassiana (since renamed Beauveria bassiana, a widely used biocontrol agent)…An exact understanding…allowed Bassi to work out methods to prevent its spread through the silkworm nurseries. After twenty years of arduous labor, he published in 1836…Although unable to see the bacterial agents of disease because of blindness, Bassi envisioned from his studies on the mal del segno the bacteriological era which was to revolutionize medicine two decades after his death.”

Chemist Jean Baptiste Dumas, Pasteur’s mentor, prevailed upon the reluctant free lance scientist to head a mission of the French Ministry of Agriculture. “Although Pasteur knew nothing of silkworms or their diseases, he accepted the challenge,” wrote Dubos. “To Pasteur’s remark that he was totally unfamiliar with the subject, Dumas had replied one day: ‘So much the better! For ideas, you will have only those which shall come to you as a result of your observations!’”

A way of life was also at stake. As described in 19th century France by Emile Duclaux, Pasteur’s student and intimate collaborator (in Dubos’ book): “…the cocoons are put into a steam bath, to kill the chrysalids by heat. In this case, scarcely six weeks separate the time of egg-hatching from the time when the cocoons are carried to market, from the time the silk grower sows to the time when he reaps. As, in former times, the harvest was almost certain and quite lucrative, the Time of the Silkworm was a time of festival and of joy, in spite of the fatigues which it imposed, and, in gratitude, the mulberry tree had received the name of arbre d’or, from the populations who derived their livelihood from it.”

“The study of silkworm diseases constituted for Pasteur an initiation into the problem of infectious diseases,” wrote Dubos, who was influenced by the famous Russian soil microbiologist, Serge Winogradsky, who favored studying microbial interactions in natural environments rather than in pure laboratory cultures. “Instead of the accuracy of laboratory procedures he encountered the variability and unpredictability of behavior in animal life, for silkworms differ in their response to disease as do other animals. In the case of flacherie (a disease), for example, the time of death after infection might vary from 12 hours to 3 weeks, and some of the worms invariably escaped death…Time and time again, he discussed the matter of the influence of environmental factors on susceptibility, on the receptivity of the ‘terrain’ for the invading agent of disease. So deep was his concern with the physiological factors that condition infection that he once wrote, ‘If I had to undertake new studies on silkworms, I would investigate conditions for increasing their vigor, a problem of which one knows nothing. This would certainly lead to techniques for protecting them against accidental diseases.’”

“Usually, the public sees only the finished result of the scientific effort, but remains unaware of the atmosphere of confusion, tentative gropings, frustration and heart-breaking discouragement in which the scientist often labors while trying to extract, from the entrails of nature, the products and laws which appear so simple and orderly when they finally reach textbooks and newspapers,” wrote Dubos. “In many circumstances, he developed reproducible and practical techniques that in other hands failed, or gave such erratic results as to be considered worthless. His experimental achievements appear so unusual in their complete success that there has been a tendency to explain them away in the name of luck, but the explanation is in reality quite simple. Pasteur was a master experimenter with an uncanny sense of the details relevant to the success of his tests. It was the exacting conscience with which he respected the most minute details of his operations, and his intense concentration while at work, that gave him an apparently intuitive awareness of all the facts significant for the test, and permitted him always to duplicate his experimental conditions. In many cases, he lacked complete understanding of the reasons for the success of the procedures that he used, but always he knew how to make them work again, if they had once worked in his hands.”

Though famed for disproving the spontaneous generation of life, immunization via attenuated living vaccines and the germ theory of infectious disease: “Pasteur often emphasized the great importance of the environment, of nutrition, and of the physiological and even psychological state of the patient, in deciding the outcome of the infectious process,” wrote Dubos. “Had the opportunity come for him to undertake again the study of silkworm diseases, he once said, he would have liked to investigate the factors which favor the general robustness of the worms, and thereby increase their resistance to infectious disease…A logic of Pasteur’s life centered on physiological problems is just as plausible as that which resulted from the exclusive emphasis on the germ theory of contagious disease.”

The 21st century is riddled with insect colony conundrums and mysteries. For example, why among the social insects are honey bees plagued by Colony Collapse Disorder, while “Colony Expansion Disorder” prevails for other social insects in the USA. Rather than collapsing, USA colonies of Argentine ants are forming “super-colonies,” and red imported fire ant colonies are growing stronger by the day and annually expanding their North American geographic range; this despite being deliberately dosed with pesticides and attacked by biocontrol organisms (perhaps even more so than the beleaguered honey bees). And quite independently of mortgage rates and housing sales, Formosan subterranean termite colonies damaging billions of dollars of USA housing stock are happily munching away at both live trees and “dead-tree” wooden housing assets with little collective danger of colony collapse, though individual colonies come and go.

Perhaps beekeeping and crop pollination would be easier if Colony Collapse Disorder were an actual “disorder” as defined by the Diagnostic and Statistical Manual of Mental Disorders (DSM), and honey bees were endowed with sufficient consciousness and behaviors amenable to bee psychology or psychiatry.

The very real plight of honey bee colonies or hives is still in what Dubos would call the “atmosphere of confusion, tentative gropings, frustration.” At the most recent Entomological Society of America annual meeting, roughly a century and a half after silkworm colony collapse was eliminated by better more sanitary rearing practices, honey bee health was still puzzling. Honey bee colony loss in Virginia increased to 30% from 5-10% in recent years, possibly due to disease pathogens, pesticides and immune system suppression, say Virginia Tech researchers (e.g. Brenna Traver) studying glucose oxidase (GOX), an indicator of immunity in social insects. Honey bee social immunity is complex, involving factors as diverse as pheromones and grooming, and honey bee production of hydrogen peroxide (H2O2), which sterilizes food for the colony.

Nosema ceranae, a global gut pathogen, was seen all around the USA in 2007 at the same time as Colony Collapse Disorder. Black queen cell virus is another culprit, along with deformed wing virus, which is spread among honey bees by varroa mites. Then it is hard to overlook that over 120 different pesticides and their metabolites have been found in honey; including common beekeeper-applied pesticides such as coumaphos, fluvalinate, chlorothalonil and the antibiotic fumagillin. At the University of Puerto Rico, Gloria Dominguez-Bello is testing oxytetracycline and other commonly used antibiotics for their effects on honey bee microbes similar to those known to affect everything from obesity and brain function to organ transplants.

Those familiar with Pasteur’s entomological research on silkworm colony collapse in the 1800s would have experienced a sense of deja vu at the most recent Entomological Society of America meetings listening to Gloria DeGrandi-Hoffman, a research leader at the USDA-ARS Carl Hayden Bee Research Center in Tucson, Arizona. Nutrition, stress and pesticides may indeed be involved, but more focus is warranted for honey bee microbial health and gut microbes. Honey bee nutrition and microbiology is complicated by seasonal variations with changing food sources. According to DeGrandi-Hoffman, a lack of beneficial microbes may set honey bees up for infectious diseases like chalkbrood.

For example, pesticides used for Varroa mite control and potent beekeeping antibiotics like thymol and formic acid can affect the Lactobacillus microbes bees need for digestion and preservation of pollen as beebread, said DeGrandi-Hoffman. When bacterial plasmids found in high numbers in beebread are plated with the pathogen Aspergillus flavus, the pathogen rapidly loses virulence.

It is likely honey bees rely on beneficial microbes to protect from harmful pathogens, as honey bees have among the fewest immune system genes of any insect. Thus, when California almond growers spray fungicides, insecticides and miticides, a side effect could be fewer beneficial microbes in honey bee guts and in beebread. Thus, the honey bees would be less healthy and more susceptible to diseases like chalkbrood. Probiotic supplements designed to add beneficial microbes to honey bee diets are being tested in some California orchards. No doubt a familiar concept to those shopping for probiotic yogurts.


Richard Feynman’s Nontoxic Ant Ferry

June 2, 2010

RICHARD FEYNMAN, CALTECH’S Nobel Prize winning physicist (1965; quantum electrodynamics), was a Princeton University graduate student during the early years of World War II when foraging ants crawled in his bay window and spurred development of an ant control device that did not kill the creatures. It was not quite as momentous as the proverbial apple conking Isaac Newton on the head in 1666 and waking him up to gravity. But according to Mathpages.com, Feynman’s “analysis of the behavior of ants involves some of the same ideas that were central to his work in theoretical physics.”

On a more mundane note, Feynman recounts the experience in his 1985 book, Surely You’re Joking, Mr. Feynman!: “In Princeton the ants found my larder, where I had jelly and bread and stuff, which was quite a distance from the window. A long line of ants marched along the floor across the living room. It was during the time I was doing these experiments on ants, so I thought to myself, ‘What can I do to stop them from coming to my larder without killing any ants? No poison; you gotta be humane to the ants!'”

Interesting sentiments coming from a man who worked on the Manhattan Project in New Mexico to help develop atomic energy into the bombs dropped on Japan to end World War II. But, of course, the goal of the Manhattan Project was to build the bomb ahead of Hitler’s scientists working in Europe. Peace and freedom were envisioned at the end of the atomic trail.

“One question that I wondered about was why the ant trails look so straight and nice,” wrote Feynman in his oft-reprinted 1985 book. “The ants look as if they know what they’re doing, as if they have a good sense of geometry. Yet the experiments that I did to try to demonstrate their sense of geometry didn’t work. Many years later, when I was at Caltech and lived in a little house on Alameda Street, some ants came out around the bathtub. I thought, ‘This is a great opportunity.’ I put some sugar on the other end of the bathtub, and sat there the whole afternoon until an ant finally found the sugar. It’s only a question of patience.”

Today we know that ants are putting down a pheromone trail, and that over time the trails most frequented (i.e with food at the end) get a stronger dose of pheromone while the pheromone disappears from the least-wandered trails. Feynman’s observations are called Ant Logic or Ant Colony Optimization by those who, in or out of the bathtub, today study the trail-following process, oftentimes using virtual ants in computer simulations for Internet routing, robotics, and business and travel solutions.

Apparently, via pheromone trails between their nest and food resources, in their everyday life ants have mastered a workable solution to what is called The Traveling Salesman Problem, which the web site of the same name (abbrev. TSP) calls “one of the most intensively studied problems in computational mathematics.”

Planning the best route between a hundred cities for a traveling rock band or the quickest path for sending data packets among thousands of Internet nodes on the Worldwide Web can apparently overheat and exhaust modern computers. In a chapter titled “Ant Logic” in The Perfect Swarm, book author Len Fisher says: “To calculate the optimal route that Ulysses might have taken between the 16 cities mentioned in The Odyssey, for example, requires the evaluation of 653,837,184,000 possible routes.” That works out to “ten thousand billion calculations” for a relatively simple travel problem.

Fortunately, Nobel Prize-caliber calculations were not needed to disrupt ant trails and humanely protect Feynman’s Princeton larder or Pasadena home. ANT FERRY was the name Feynman gave to his least-toxic ant removal device: “I made a lot of little strips of paper and put a fold in them, so I could pick up ants and ferry them from one place to another,” wrote Feynman in Surely You’re Joking, Mr. Feynman!.

“What I did was this: In preparation, I put a bit of sugar about 6 or 8 inches from their entry point into the room, that they didn’t know about. Then I made those ferry things again, and whenever an ant returning with food walked onto my little ferry, I’d carry him over and put him on the sugar. Any ant coming toward the larder that walked onto a ferry I also carried over to the sugar. Eventually the ants found their way from the sugar to their hole, so this new trail was being doubly reinforced, while the old trail was being used less and less. I knew that after half an hour or so the old trail would dry up, and in an hour they were out of my larder. I didn’t wash the floor. I didn’t do anything but ferry ants.”

No Nobel Prize is needed to obliterate ant trails and naturally protect larders without toxins or even killing any ants. However, the patience, the extra hour, may be outside the modern mindset. Nonetheless, thank you Mr. Feynman for what your colleagues call a PROOF of CONCEPT.


Headless Zombie Fire Ants, Brain-Eating Flies!

January 15, 2010

FIRE ANTS ATTACKED by BRAIN-EATING FLY MAGGOTS, transformed into HEADLESS ZOMBIES. So says the ever-helpful Kavita Sharma, an Auburn University entomologist in fire ant-plagued Alabama, a likely port of disembarkation for the painfully-biting red imported fire ant invasion of the United States that began in earnest during World War II.

If you missed it on the evening news or failed to scan the supermarket tabloid headlines, the Internet tabloid journalists have had fun dramatizing it on You Tube. Not that the brain-eating flies have yet provided much relief from the ever-expanding, biting fire ant invasion raging from Texas, Oklahoma and New Mexico to Florida and the Carolinas. Indeed, the ants may be bent on global colonization, having expanded from their South America homeland in Argentina to North America, Australia and other continents.

Several decades of pesticide spraying, and more recently poison baits, have done little to slow the spread of the biting ants, which have effectively colonized the southern U.S. and seem to be adapting to slightly cooler northern climes. Not that it is all bad, if you can avoid being bitten. The ravenous ants provide vital biological pest control on some farms; for example ridding cotton farms of bollworms, weevils and other pests that would otherwise be sprayed with pesticides. No doubt, the ants would also make mincemeat and hash out of any bedbugs in an infested mattress placed in their path.

But the pain of the bites and the problematic fire ant mounds erupting in lawns and pastures necessitate control measures. As is typical of pest control programs, years of failed but costly chemical eradication eventually breed pesticide-resistant insects. Score one point for the fire ants and Darwin’s theory of evolution. Score good revenues for valiant pest control efforts. But longer term, insect genetics adapt to almost anything thrown at them.

In the 1954 sci-fi flick, Them, even Fess Parker (Davy Crockett fame), Leonard Nimoy (an uncredited, pre-Star Trek role) and James Whitmore’s bullets failed to stem a mutant ant invasion linked to atomic tests. But James Arness (of later Gunsmoke fame) finally routed the giant mutant ants colonizing downtown Los Angeles with an orgy of messy napalm-like flame throwers. Poison baits minimizing environmental contamination and brain-eating flies providing biological ant control look elegant in comparison. Indeed, pest control has come a long way in the half century since Rachel Carson railed against pesticides.

In her poster display at the Entomological Society of America (ESA) annual meeting in downtown Indianapolis, Kavita Sharma provided scientific details on how the brain-eating phorid flies locate fresh worker fire ant brains and turn the ants into zombies. Pheromone-like chemicals may be involved. One of the phorid fly species introduced into the U.S. from Argentina for fire ant biocontrol is literally super-efficient and would make time management experts proud. When not in the maggot stage eating ant brains, adult flies combine mating with searching out worker fire ants with nourishing brains to attack. No doubt more to come on You Tube’s Zombie Ant Channel.