Strigolactones stimulate arbuscular mycorrhizal fungi by activating mitochondria

The association of arbuscular mycorrhizal (AM) fungi with plant roots is the oldest and ecologically most important symbiotic relationship between higher plants and microorganisms, yet the mechanism by which these fungi detect the presence of a plant host is poorly understood. Previous studies have shown that roots secrete a branching factor (BF) that strongly stimulates branching of hyphae during germination of the spores of AM fungi. In the BF of Lotus, a strigolactone was found to be the active molecule. Strigolactones are known as germination stimulants of the parasitic plants Striga and Orobanche. In this paper, we show that the BF of a monocotyledonous plant, Sorghum, also contains a strigolactone. Strigolactones strongly and rapidly stimulated cell proliferation of the AM fungus Gigaspora rosea at concentrations as low as 10(-13) M. This effect was not found with other sesquiterperne lactones known as germination stimulants of parasitic weeds. Within 1 h of treatment, the density of mitochondria in the fungal cells increased, and their shape and movement changed dramatically. Strigolactones stimulated spore germination of two other phylogenetically distant AM fungi, Glomus intraradices and Gl. claroideum. This was also associated with a rapid increase of mitochondrial density and respiration as shown with Gl. intraradices. We conclude that strigolactones are important rhizospheric plant signals involved in stimulating both the pre-symbiotic growth of AM fungi and the germination of parasitic plants.

Curcuminoids and sesquiterpenoids in turmeric (Curcuma longa L.) suppress an increase in blood glucose level in type 2 diabetic KK-Ay mice

Turmeric, the rhizome of Curcuma longa L., has a wide range of effects on human health. The chemistry includes curcuminoids and sesquiterpenoids as components, which are known to have antioxidative, anticarcinogenic, and antiinflammatory activities. In this study, we investigated the effects of three turmeric extracts on blood glucose levels in type 2 diabetic KK-A(y) mice (6 weeks old, n = 5/group). These turmeric extracts were obtained by ethanol extraction (E-ext) to yield both curcuminoids and sesquiterpenoids, hexane extraction (H-ext) to yield sesquiterpenoids, and ethanol extraction from hexane-extraction residue (HE-ext) to yield curcuminoids. The control group was fed a basal diet, while the other groups were fed a diet containing 0.1 or 0.5 g of H-ext or HE-ext/100 g of diet or 0.2 or 1.0 g of E-ext/100 g of diet for 4 weeks. Although blood glucose levels in the control group significantly increased (P < 0.01) after 4 weeks, feeding of 0.2 or 1.0 g of E-ext, 0.5 g of H-ext, and 0.5 g of HE-ext/100 g of diet suppressed the significant increase in blood glucose levels. Furthermore, E-ext stimulated human adipocyte differentiation, and these turmeric extracts had human peroxisome proliferator-activated receptor-gamma (PPAR-gamma) ligand-binding activity in a GAL4-PPAR-gamma chimera assay. Also, curcumin, demethoxycurcumin, bisdemethoxycurcumin, and ar-turmerone had PPAR-gamma ligand-binding activity. These results indicate that both curcuminoids and sesquiterpenoids in turmeric exhibit hypoglycemic effects via PPAR-gamma activation as one of the mechanisms, and suggest that E-ext including curcuminoids and sesquiterpenoids has the additive or synergistic effects of both components.

Chemical composition and antioxidant properties of clove leaf essential oil

The antioxidant activity of a commercial rectified clove leaf essential oil (Eugenia caryophyllus) and its main constituent eugenol was tested. This essential oil comprises in total 23 identified constituents, among them eugenol (76.8%), followed by beta-caryophyllene (17.4%), alpha-humulene (2.1%), and eugenyl acetate (1.2%) as the main components. The essential oil from clove demonstrated scavenging activity against the 2,2-diphenyl-1-picryl hydracyl (DPPH) radical at concentrations lower than the concentrations of eugenol, butylated hydroxytoluene (BHT), and butylated hydroxyanisole (BHA). This essential oil also showed a significant inhibitory effect against hydroxyl radicals and acted as an iron chelator. With respect to the lipid peroxidation, the inhibitory activity of clove oil determined using a linoleic acid emulsion system indicated a higher antioxidant activity than the standard BHT.

Fake antimalarials in Southeast Asia are a major impediment to malaria control: multinational cross-sectional survey on the prevalence of fake antimalarials

OBJECTIVE

To assess the prevalence of counterfeit antimalarial drugs in Southeast (SE) Asia.

DESIGN

Cross-sectional survey.

SETTING

Pharmacies and shops selling antimalarial drugs in Myanmar (Burma), Lao PDR, Vietnam, Cambodia and Thailand.

MAIN OUTCOME MEASURES

Proportion of artemisinin derivatives or mefloquine containing drugs of substandard quality.

RESULTS

Of the 188 tablet packs purchased which were labelled as 'artesunate' 53% did not contain any artesunate. All counterfeit artesunate tablets were labelled as manufactured by 'Guilin Pharma', and refinements of the fake blisterpacks made them often hard to distinguish from their genuine counterparts. No other artemisinin derivatives were found to be counterfeited. Of the 44 mefloquine samples, 9% contained <10% of the expected amount of active ingredient.

CONCLUSIONS

An alarmingly high proportion of antimalarial drugs bought in pharmacies and shops in mainland SE Asia are counterfeit, and the problem has increased significantly compared with our previous survey in 1999-2000. This is a serious threat to public health in the region.

A collaborative epidemiological investigation into the criminal fake artesunate trade in South East Asia

BACKGROUND

Since 1998 the serious public health problem in South East Asia of counterfeit artesunate, containing no or subtherapeutic amounts of the active antimalarial ingredient, has led to deaths from untreated malaria, reduced confidence in this vital drug, large economic losses for the legitimate manufacturers, and concerns that artemisinin resistance might be engendered.

METHODS AND FINDINGS

With evidence of a deteriorating situation, a group of police, criminal analysts, chemists, palynologists, and health workers collaborated to determine the source of these counterfeits under the auspices of the International Criminal Police Organization (INTERPOL) and the Western Pacific World Health Organization Regional Office. A total of 391 samples of genuine and counterfeit artesunate collected in Vietnam (75), Cambodia (48), Lao PDR (115), Myanmar (Burma) (137) and the Thai/Myanmar border (16), were available for analysis. Sixteen different fake hologram types were identified. High-performance liquid chromatography and/or mass spectrometry confirmed that all specimens thought to be counterfeit (195/391, 49.9%) on the basis of packaging contained no or small quantities of artesunate (up to 12 mg per tablet as opposed to approximately 50 mg per genuine tablet). Chemical analysis demonstrated a wide diversity of wrong active ingredients, including banned pharmaceuticals, such as metamizole, and safrole, a carcinogen, and raw material for manufacture of methylenedioxymethamphetamine ('ecstasy'). Evidence from chemical, mineralogical, biological, and packaging analysis suggested that at least some of the counterfeits were manufactured in southeast People's Republic of China. This evidence prompted the Chinese Government to act quickly against the criminal traders with arrests and seizures.

CONCLUSIONS

An international multi-disciplinary group obtained evidence that some of the counterfeit artesunate was manufactured in China, and this prompted a criminal investigation. International cross-disciplinary collaborations may be appropriate in the investigation of other serious counterfeit medicine public health problems elsewhere, but strengthening of international collaborations and forensic and drug regulatory authority capacity will be required.

The antimalarial drug artemisinin alkylates heme in infected mice

Heme alkylation by the antimalarial drug artemisinin is reported in vivo, within infected mice that have been treated at pharmacologically relevant doses. Adducts resulting from the alkylation of heme by the drug were characterized in the spleen of treated mice, and their glucuroconjugated derivatives were present in the urine. Because these heme-artemisinin adducts were not observed in noninfected mice, this report confirms that the alkylating activity of this antimalarial drug is related to the presence of the parasite in infected animals. The identification of heme-artemisinin adducts in mice should be considered as the signature of the alkylation capacity of artemisinin in vivo.

Petasites hybridus root (butterbur) is an effective preventive treatment for migraine

Objective: To evaluate the clinical efficacy of a standardized special root extract from the plant Petasites hybridus as a preventive therapy for migraine.

Methods: This is a three-arm, parallel-group, randomized trial comparing Petasites extract 75 mg bid, Petasites extract 50 mg bid, or placebo bid in 245 patients with migraine. Eligible patients met International Headache Society criteria for migraine, were ages 18 to 65, and had at least two to six attacks per month over the preceding 3 months. The main outcome measure was the decrease in migraine attack frequency per month calculated as percentage change from baseline over a 4-month treatment period.

Results: Over 4 months of treatment, in the per-protocol analysis, migraine attack frequency was reduced by 48% for Petasites extract 75 mg bid (p = 0.0012 vs placebo), 36% for Petasites extract 50 mg bid (p = 0.127 vs placebo), and 26% for the placebo group. The proportion of patients with a ≥50% reduction in attack frequency after 4 months was 68% for patients in the Petasites extract 75-mg arm and 49% for the placebo arm (p < 0.05). Results were also significant in favor of Petasites 75 mg at 1, 2, and 3 months based on this endpoint. The most frequently reported adverse reactions considered possibly related to treatment were mild gastrointestinal events, predominantly burping.

Conclusions:Petasites extract 75 mg bid is more effective than placebo and is well tolerated as a preventive therapy for migraine. Petasites 50 mg PO bid was not significantly more effective than placebo on the primary study endpoints.

Mass spectrometry screening reveals widespread diversity in trichome specialized metabolites of tomato chromosomal substitution lines

Glandular secreting trichomes of cultivated tomato (Solanum lycopersicum) and close relatives produce a variety of structurally diverse volatile and non-volatile specialized ('secondary') metabolites, including terpenes, flavonoids and acyl sugars. A genetic screen is described here to profile leaf trichome and surface metabolite extracts of nearly isogenic chromosomal substitution lines covering the tomato genome. These lines contain specific regions of the Solanum pennellii LA0716 genome in an otherwise 'wild-type' M82 tomato genetic background. Regions that have an impact on the total amount of extractable mono- and sesquiterpenes (IL2-2) or only sesquiterpenes (IL10-3) or specifically influence accumulation of the monoterpene alpha-thujene (IL1-3 and IL1-4) were identified using GC-MS. A rapid LC-TOF-MS method was developed and used to identify changes in non-volatile metabolites through non-targeted analysis. Metabolite profiles generated using this approach led to the discovery of introgression lines producing different acyl chain substitutions on acyl sugar metabolites (IL1-3/1-4 and IL8-1/8-1-1), as well as two regions that influence the quantity of acyl sugars (IL5-3 and IL11-3). Chromosomal region 1-1/1-1-3 was found to influence the types of glycoalkaloids that are detected in leaf surface extracts. These results show that direct chemical screening is a powerful way to characterize genetic diversity in trichome specialized metabolism.

Current status of artemisinin and its derivatives as antimalarial drugs

Artemisinin is a promising and a potent antimalarial drug, which meets the dual challenge posed by drug-resistant parasites and rapid progression of malarial illness. This review article focuses on the progress achieved during the last years in the production of artemisinin from Artemisia annua. The structure, biosynthesis and analysis of artemisinin and its mode of action are described. The review also focuses on clinical studies, toxicity studies, pharmacokinetics and activity of artemisinin related compounds. The production strategies including organic synthesis, extraction from plants, in vitro cultures and alternative strategies for enhancing the yields are also discussed.

Trichothecene mycotoxins in aerosolized conidia of Stachybotrys atra

Stachybotrys atra is the etiologic agent of stachybotryotoxicosis, and this fungus and its trichothecene mycotoxins were recently implicated in an outbreak of unexplained illness in homes. S. atra was grown on sterile rice, autoclaved, dried, and then aerosolized by acoustic vibration. The distribution of particles (mass and number) was monitored on an aerodynamic particle sizer interfaced with a computer. Dust was collected on preweighed glass-fiber filters and extracted with 90% aqueous methanol. Extracts were tested for the ability to inhibit protein synthesis in rat alveolar macrophages, the ability to inhibit the proliferation of mouse thymocytes, and the presence of specific trichothecene mycotoxins. Virtually all of the particles were less than 15 micron in aerodynamic diameter, and the mass median diameter was 5 micron. Thus, most of the particles were respirable. Microscopic analysis of the generated dust revealed that ca. 85% of the dust particles were conidia of S. atra, another 6% were hyphal fragments, and the remainder of the particles were unidentifiable. Thus, greater than 90% of the particles were of fungal origin. The extracts strongly inhibited protein synthesis and thymocyte proliferation. Purified satratoxin H was also highly toxic in the same systems. Each of the individual filters contained satratoxin H (average, 9.5 ng/mg of dust). Satratoxin G and trichoverrols A and B were found in lesser amounts in some, but not all, of the filters. The limit of analysis is ca. 50 ng. These results establish that the conidia of S. atra contain trichothecene mycotoxins. In view of the potent toxicity of the trichothecenes, the inhalation of aerosols containing high concentrations of these conidia could be a potential hazard to health.

Citrus fruit flavor and aroma biosynthesis: isolation, functional characterization, and developmental regulation of Cstps1, a key gene in the production of the sesquiterpene aroma compound valencene

Citrus fruits possess unique aromas rarely found in other fruit species. While fruit flavor is composed of complex combinations of soluble and volatile compounds, several low-abundance sesquiterpenes, such as valencene, nootkatone, alpha-sinensal, and beta-sinensal, stand out in citrus as important flavor and aroma compounds. The profile of terpenoid volatiles in various citrus species and their importance as aroma compounds have been studied in detail, but much is still lacking in our understanding of the physiological, biochemical, and genetic regulation of their production. Here, we report on the isolation, functional expression, and developmental regulation of Cstps1, a sesquiterpene synthase-encoding gene, involved in citrus aroma formation. The recombinant enzyme encoded by Cstps1 was shown to convert farnesyl diphosphate to a single sesquiterpene product identified as valencene by gas chromatography-mass spectrometry (GC-MS). Phylogenetic analysis of plant terpene synthase genes localized Cstps1 to the group of angiosperm sesquiterpene synthases. Within this group, Cstps1 belongs to a subgroup of citrus sesquiterpene synthases. Cstps1 was found to be developmentally regulated: transcript was found to accumulate only towards fruit maturation, corresponding well with the timing of valencene accumulation in fruit. Although citrus fruits are non-climacteric, valencene accumulation and Cstps1 expression were found to be responsive to ethylene, providing further evidence for the role of ethylene in the final stages of citrus fruit ripening. Isolation of the gene encoding valencene synthase provides a tool for an in-depth study of the regulation of aroma compound biosynthesis in citrus and for metabolic engineering for fruit flavor characteristics.

Role of trichomes in defense against herbivores: comparison of herbivore response to woolly and hairless trichome mutants in tomato (Solanum lycopersicum)

Trichomes contribute to plant resistance against herbivory by physical and chemical deterrents. To better understand their role in plant defense, we systemically studied trichome morphology, chemical composition and the response of the insect herbivores Helicoverpa zea and Leptinotarsa decemlineata (Colorado potato beetle = CPB) on the tomato hairless (hl), hairy (woolly) mutants and wild-type Rutgers (RU) and Alisa Craig (AC) plants. Hairless mutants showed reduced number of twisted glandular trichomes (types I, IV, VI and VII) on leaf and stem compared to wild-type Rutgers (RU), while woolly mutants showed high density of non-glandular trichomes (types II, III and V) but only on the leaf. In both mutants, trichome numbers were increased by methyl jasmonate (MeJA), but the types of trichomes present were not affected by MeJA treatment. Glandular trichomes contained high levels of monoterpenes and sesquiterpenes. A similar pattern of transcript accumulation was observed for monoterpene MTS1 (=TPS5) and sesquiterpene synthase SST1 (=TPS9) genes in trichomes. While high density of non-glandular trichome on leaves negatively influenced CPB feeding behavior and growth, it stimulated H. zea growth. High glandular trichome density impaired H. zea growth, but had no effect on CPB. Quantitative real-time polymerase chain reaction (qRT-PCR) showed that glandular trichomes highly express protein inhibitors (PIN2), polyphenol oxidase (PPOF) and hydroperoxide lyase (HPL) when compared to non-glandular trichomes. The SlCycB2 gene, which participates in woolly trichome formation, was highly expressed in the woolly mutant trichomes. PIN2 in trichomes was highly induced by insect feeding in both mutant and wild-type plants. Thus, both the densities of trichomes and the chemical defenses residing in the trichomes are inducible.

Co-identity of the refusal and emetic principle from Fusarium-infected corn

The structure of vomitoxin isolated from Fusarium-contaminated corn was proved to be 3,7,15-trihydroxy-12,13-epoxytrichothec-9-en-8-one. This same toxin is responsible for the "refusal phenomenon" exhibited by swine fed contaminated corn. In addition, two new substances believed to be trichothecenes were isolated from naturally infected corn. Vomitoxin was also isolated from rice inoculated with F. graminearium NRRL 5883.

Immunomodulatory active compounds from Tinospora cordifolia

ETHNOPHARMACOLOGICAL RELEVANCE

Tinospora cordifolia mentioned as "Rasayana" is extensively used in various herbal preparations for the treatment of different ailments for its general tonic, antiperiodic, antispasmodic, antiinflammatory, antiarthritic, antiallergic and antidiabetic properties. It is extensively used in Ayurveda due to its potential in improving the immune system and the body resistance against infections.

AIM OF THE STUDY

The aim of the study was to isolate and characterise the immunomodulatory active compounds of Tinospora cordifolia.

MATERIALS AND METHODS

The immunomodulatory activity of different extracts, fractions and isolated compounds in relation to phagocytosis and reactive oxygen species production in human neutrophil cells have been investigated using the PMN phagocytic function studies, NBT, NO and chemiluminescence assay.

RESULTS

The results obtained indicate that ethyl acetate, water fractions and hot water extract exhibited significant immunomodulatory activity with an increase in percentage phagocyctosis. Chromatographic purification of these fraction led to the isolation of a mixture of two compounds 2, 3 isolated for the first time from natural source and five known compounds 1, 4-7 which were characterized as 11-hydroxymustakone (2), N-methyl-2-pyrrolidone (3), N-formylannonain (1), cordifolioside A (4), magnoflorine (5), tinocordiside (6), syringin (7) by nuclear magnetic resonance (NMR) and mass spectrometry (MS) and comparing the spectral data with reported one. Cordifolioside A and syringin have been reported to possess immunomodulatory activity. Other five compounds showed significant enhancement in phagocytic activity and increase in nitric oxide and reactive oxygen species generation at concentration 0.1-2.5 μg/ml.

CONCLUSIONS

Seven immunomodulatory active compounds belonging to different classes have been isolated and characterised indicating that the immunomodulatory activity of Tinospora cordifolia may be attributed to the synergistic effect of group of compounds.

Manslaughter by fake artesunate in Asia--will Africa be next?

Fake artesunate could compromise the hope that artemisinin-based combination therapy offers for malaria control in Africa and Asia.

Liquid and vapour-phase antifungal activities of selected essential oils against Candida albicans: microscopic observations and chemical characterization of Cymbopogon citratus

BACKGROUND

Use of essential oils for controlling Candida albicans growth has gained significance due to the resistance acquired by pathogens towards a number of widely-used drugs. The aim of this study was to test the antifungal activity of selected essential oils against Candida albicans in liquid and vapour phase and to determine the chemical composition and mechanism of action of most potent essential oil.

METHODS

Minimum Inhibitory concentration (MIC) of different essential oils in liquid phase, assayed through agar plate dilution, broth dilution & 96-well micro plate dilution method and vapour phase activity evaluated through disc volatilization method. Reduction of C. albicans cells with vapour exposure was estimated by kill time assay. Morphological alteration in treated/untreated C. albicans cells was observed by the Scanning electron microscopy (SEM)/Atomic force microscopy (AFM) and chemical analysis of the strongest antifungal agent/essential oil has been done by GC, GC-MS.

RESULTS

Lemon grass (Cymbopogon citratus) essential oil exhibited the strongest antifungal effect followed by mentha (Mentha piperita) and eucalyptus (Eucalyptus globulus) essential oil. The MIC of lemon grass essential oil in liquid phase (288 mg/l) was significantly higher than that in the vapour phase (32.7 mg/l) and a 4 h exposure was sufficient to cause 100% loss in viability of C. albicans cells. SEM/AFM of C. albicans cells treated with lemon grass essential oil at MIC level in liquid and vapour phase showed prominent shrinkage and partial degradation, respectively, confirming higher efficacy of vapour phase. GC-MS analysis revealed that lemon grass essential oil was dominated by oxygenated monoterpenes (78.2%); α-citral or geranial (36.2%) and β-citral or neral (26.5%), monoterpene hydrocarbons (7.9%) and sesquiterpene hydrocarbons (3.8%).

CONCLUSION

Lemon grass essential oil is highly effective in vapour phase against C. albicans, leading to deleterious morphological changes in cellular structures and cell surface alterations.

Seasonal variation of artemisinin and its biosynthetic precursors in plants of Artemisia annua of different geographical origin: proof for the existence of chemotypes

The time course of the levels of artemisinin, its biosynthetic precursors and the biosynthetically related sesquiterpenes was monitored during a vegetation period of Artemisia annua plants of different geographical origin. Considerable differences in contents of artemisinin and its direct precursors artemisinic acid and dihydroartemisinic acid were found between these A. annua's. For the first time the A. annua plants of different geographical origin were found to belong to different chemotypes. A chemotype with a high artemisinin level was found to have also a high dihydroartemisinic acid level but a relatively low artemisinic acid level. Reversibly, a chemotype with low levels of artemisinin and dihydroartemisinic acid contained a high artemisinic acid level. Artemisinic acid is considered to be the direct precursor of dihydroartemisinic acid in the biosynthetic pathway of artemisinin. The observed accumulation of artemisinic acid in one of the A. annua chemotypes may indicate the presence of a rate-limiting step in the biosynthetic pathway of artemisinin. The enzymatic reduction of artemisinic acid into dihydroartemisinic acid is probably a "bottle neck" in the biosynthetic pathway of artemisinin in varieties with high artemisinic acid and consequentially low artemisinin levels. After a night-frost period, the level of artemisinin was increased, in the Vietnamese A. annua plants, while the dihydroartemisinic acid level was decreased. This phenomenon is in accordance with our hypothesis that stress triggers the conversion of dihydroartemisinic acid to artemisinin. It is suggested that the presence of high levels of dihydroartemisinic acid may be an adaptation to stress conditions (e.g., night-frost), during which relatively high levels of 1O2 are formed. Dihydroartemisinic acid gives the plant protection by reacting with these reactive oxygen species yielding artemisinin as stable end-product.

From wine to pepper: rotundone, an obscure sesquiterpene, is a potent spicy aroma compound

An obscure sesquiterpene, rotundone, has been identified as a hitherto unrecognized important aroma impact compound with a strong spicy, peppercorn aroma. Excellent correlations were observed between the concentration of rotundone and the mean 'black pepper' aroma intensity rated by sensory panels for both grape and wine samples, indicating that rotundone is a major contributor to peppery characters in Shiraz grapes and wine (and to a lesser extent in wine of other varieties). Approximately 80% of a sensory panel were very sensitive to the aroma of rotundone (aroma detection threshold levels of 16 ng/L in red wine and 8 ng/L in water). Above these concentrations, these panelists described the spiked samples as more 'peppery' and 'spicy'. However, approximately 20% of panelists could not detect this compound at the highest concentration tested (4000 ng/L), even in water. Thus, the sensory experiences of two consumers enjoying the same glass of Shiraz wine might be very different. Rotundone was found in much higher amounts in other common herbs and spices, especially black and white peppercorns, where it was present at approximately 10000 times the level found in very 'peppery' wine. Rotundone is the first compound found in black or white peppercorns that has a distinctive peppery aroma. Rotundone has an odor activity value in pepper on the order of 50000-250000 and is, on this criterion, by far the most powerful aroma compound yet found in that most important spice.

Solid phase microextraction for quantitative headspace sampling of apple volatiles

Solid phase microextraction (SPME) was evaluated for use in the quantification of aroma volatile production by Granny Smith apples during cool storage. Particular attention was paid to quantifying alpha-farnesene (3,7,11-trimethyldodeca-1,3(E),6(E),10-tetraene) due to its involvement in superficial scald, a disorder of cool stored apples. Comparison between SPME and solid phase extraction (SPE) showed that the SPME fiber had greater adsorption of high molecular weight (MW) volatiles such as alpha-farnesene. When sampling by SPME, these higher MW volatiles did not equilibrate between apples, headspace, and fiber within sampling times as long as 90 min, while lower MW volatiles equilibrated within 5 min. This behavior was also shown by a simple model system consisting of five selected volatiles dissolved in an involatile, lipophilic liquid (squalane). The less volatile high MW aroma compounds evaporated slowly from the surface of the apples and were depleted from the headspace because of very rapid adsorption by the SPME fiber. The amount of alpha-farnesene adsorbed by the fiber increased with air movement through the system. In a static headspace system, the amount of alpha-farnesene adsorbed by the fiber decreased nonlinearly with increasing distance from the apples, due to adsorption onto the glass walls. While SPME is ideal for rapid, qualitative determination of apple headspace volatiles, the slower equilibration of higher MW volatiles limits its use for quantification in more complex systems.

The effects of arbuscular mycorrhizal fungi on direct and indirect defense metabolites of Plantago lanceolata L

Arbuscular mycorrhizal fungi can strongly influence the metabolism of their host plant, but their effect on plant defense mechanisms has not yet been thoroughly investigated. We studied how the principal direct defenses (iridoid glycosides) and indirect defenses (volatile organic compounds) of Plantago lanceolata L. are affected by insect herbivory and mechanical wounding. Volatile compounds were collected and quantified from mycorrhizal and non-mycorrhizal P. lanceolata plants that underwent three different treatments: 1) insect herbivory, 2) mechanical wounding, or 3) no damage. The iridoids aucubin and catalpol were extracted and quantified from the same plants. Emission of terpenoid volatiles was significantly higher after insect herbivory than after the other treatments. However, herbivore-damaged mycorrhizal plants emitted lower amounts of sesquiterpenes, but not monoterpenes, than herbivore-damaged non-mycorrhizal plants. In contrast, mycorrhizal infection increased the emission of the green leaf volatile (Z)-3-hexenyl acetate in untreated control plants, making it comparable to emission from mechanically wounded or herbivore-damaged plants whether or not they had mycorrhizal associates. Neither mycorrhization nor treatment had any influence on the levels of iridoid glycosides. Thus, mycorrhizal infection did not have any effect on the levels of direct defense compounds measured in P. lanceolata. However, the large decline in herbivore-induced sesquiterpene emission may have important implications for the indirect defense potential of this species.

Heterologous production of α-farnesene in metabolically engineered strains of Yarrowia lipolytica

Herein, we studied the heterologous production of α-farnesene, a valuable sesquiterpene with various biotechnological applications, by metabolic engineering of Yarrowia lipolytica. Different overexpression vectors harboring combinations of tHMG1, IDI, ERG20 and codon-optimized α-farnesene synthase (OptFS) genes were constructed and integrated into the genome of Y. lipolytica Po1h. The engineered strain produced 57.08±1.43mg/L of α-farnesene corresponding to 20.8-fold increase over the initial production of 2.75±0.29mg/L in the YPD medium in shake flasks. Bioreactor scale-up in PM medium led to α-farnesene concentration of 259.98±2.15mg/L with α-farnesene to biomass ratio of 33.98±1.51mg/g, which was a 94.5-fold increase over the initial production. This first report on α-farnesene synthesis in Y. lipolytica lays a foundation for future research on production of sesquitepenes in Y. lipolytica and other closest yeast species and will potentially contribute in its industrial production.

Effects of components of Artemisia annua on coccidia infections in chickens

Four experiments were run to test the anticoccidial activity of dried Artemisia annua leaves and several of their chemical constituents for possible use as prophylactic feed additives. When fed over a period of 3 wk at a level of 5%, a dried leaf supplement of A. annua provided significant protection against lesions due to Eimeria tenella but not Eimeria acervulina or Eimeria maxima. When fed over a period of 5 wk at a level of 1% to chicks undergoing immunization with a live vaccine, it provided significant protection in partially immunized chicks against E. acervulina and E. tenella lesions from a dual species challenge infection. It also afforded lower mean lesion scores in challenged chicks immunized over a period of 5 wk. Artemisinin, an antimalarial component of A. annua, was present at a level of 0.034% in the dried leaf preparation. A 5% supplement thus afforded about 17 ppm artemisin. When the pure compound was fed at that level for a period of 3 wk, it protected weight gains and significantly reduced lesion scores attributable to E. tenella but not E. acervulina. Other components of A. annua, camphor and 1,8-cineole, at 119 ppm also protected weight gains, and reduced E. tenella lesion scores. Camphor reduced E. acervulina lesions. Artemisinin fed for 4 wk at levels of 2, 8.5, and 17 ppm significantly reduced oocyst output from separate E. acervulina and E. tenella infections and a dual species infection. Pure artemisinin thus appears to be effective against at least two coccidia species when used as a feed additive, and its activity may depend, in part, on the length of time it is administered before a challenge infection.