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In response to insect feeding on the leaves, cotton (Gossypium hirsutum L.) plants release elevated levels of volatiles, which can serve as a chemical signal that attracts natural enemies of the herbivore to the damaged plant. Pulse-labeling experiments with [13C]CO2 demonstrated that many of the volatiles released, including the acyclic terpenes (E,E)-alpha-farnesene, (E)-beta-farnesene, (E)-beta-ocimene, linalool,(E)-4,8-dimethyl-1,3,7-nonatriene, and (E,E)-4,8,12-trimethyl-1,3,7,11-tridecatetrane, as well as the shikimate pathway product indole, are biosynthesized de novo following insect damage. However, other volatile constituents, including several cyclic terpenes, butyrates, and green leaf volatiles of the lipoxygenase pathway are released from storage or synthesized from stored intermediates. Analysis of volatiles from artificially damaged plants, with and without beet armyworm (Spodoptera exigua Hubner) oral secretions exogenously applied to the leaves, as well as volatiles from beet armyworm-damaged and -undamaged control plants, demonstrated that the application of caterpillar oral secretions increased both the production and release of several volatiles that are synthesized de novo in response to insect feeding. These results establish that the plant plays an active and dynamic role in mediating the interaction between herbivores and natural enemies of herbivores

Butyric acid fermentation by Clostridium tyrobutyricum ATCC 25755 using glucose or brown algae as a carbon source was carried out. Initially, different fermentation modes (batch, fed-batch, and semi-continuous) at pH 6 and 37℃ were compared using a model medium containing glucose as a carbon source. By feeding the whole medium containing 40 ~ 50 and 30 g/L of glucose into the fed-batch and semi-continuous fermentations, very similar butyrate yields (0.274 and 0.252 g butyrate/g glucose, respectively) and productivities (0.362 and 0.355 g/L/h, respectively) were achieved. The highest butyrate concentration was about 50 g/L, which was observed in the fed-batch fermentation with whole medium feeding. However, semi-continuous fermentation sustained a longer fermentation cycle than the fed-batch fermentation due to end-product and metabolic waste inhibition. The established conditions were then applied to the fermentation using brown algae, Laminaria japonica and Undaria pinnatifida, as substrates for butyric acid fermentation. To hydrolyze brown algae, 7.5 ~ 10% (w/v) dried brown algae powder was suspended in 1% (w/v) NaOH or 0.5 ~ 2.5% (w/v) H₂SO₄ and then autoclaved at 121℃ for 30 ~ 90 min. The resulting butyrate concentration was about 11 g/L, which was produced from 100 g/L of L. japonica autoclaved for 60 mm in 1.5% H₂SO₄ acid solution.

Biological soil disinfestation (BSD), or reductive soil disinfestation, achieved by amendment with organic materials such as wheat bran followed by flooding and covering the soil surface, has been used to control some soilborne diseases including Fusarium wilt and bacterial wilt of tomato. During a BSD treatment, accumulation of acetic acid and/or butyric acid was detected with high-performance liquid chromatography. Survival of Fusarium oxysporum f. sp. lycopersici or Ralstonia solanacearum was suppressed by these organic acids. Amendment of these organic acids into soil suppressed the survival of R. solanacearum at lower concentrations than the maximum detected in BSD treatment, indicating that production of these organic acids is one of the mechanisms of control. However, F. oxysporum f. sp. lycopersici in soil survived with the maximum concentrations of these organic acids achieved by BSD; thus, involvement of factors other than organic acids may be involved. [PUBLICATION ABSTRACT]

More than one hundred volatile organic substances were identified by gas chromatography and mass spectrometry (GC/MS) in the indoor and outdoor air, stable and farm road dust and farm soil samples from two pig and cattle farms in the South Moravian Region. Volatile fatty acids (acetic, propanoic, butanoic and pentanoic) and their esters dominated along with aldehydes (butanal, pentanal and hexanal) and 4-methylphenol in the indoor and outdoor air samples. Road dust and soil samples contained mainly volatile aromatic compounds (toluene, benzene, ethylbenzene, styrene and xylenes), aliphatic hydrocarbons (largely n-alkanes), dichloromethane and carbon disulphide.

Changes in amino acid composition of alfalfa (Medicago sativa L.) phloem sap were studied in response to a water deficit. Sap was collected by stylectomy. As the leaf water potential decreased from -0.4 to -2.0 MPa, there was a significant increase of the total amino acid concentration, due to that of some amino acids: proline, valine, isoleucine, leucine, glutamic acid, aspartic acid, and threonine. Asparagine concentration, which is the main amino acid assayed in the phloem sap of alfalfa (it accounts for 70% of the total content), did not vary with the plant water status. The other amino acid concentrations remained stable as leaf water potential varied; in particular, gamma-amino butyric acid concentration remained unchanged, whereas it varied in response to wounding. The more striking change in the sieve tubes was the accumulation of proline which was observed below a leaf water potential threshold value of about -0.9 MPa (concentration x60 for a decrease of leaf water potential from -0.9 to -2.0 MPa). The role of such changes in phloem sap amino acid concentration in osmotic adjustment of growing tissues is discussed

The ability of the rumen ciliate Eudiplodinium maggii to utilize chitin from fungal cell wall was determined. Cultivation experiments showed that the population concentration (number of ciliates in vitro) was positively correlated with chitin doses. Cell extract prepared from the bacteria-free ciliates degraded colloidal chitin releasing 2.0 micromol reducing sugar per mg protein per h. End products of this reaction were chitotriose and N-acetylglucosamine. Incubation of the bacteria-free ciliates with chitin resulted in an increase in the concentration of acetic, propionic and butyric acids in the incubation medium. The production rate of total volatile fatty acids (VFA) by ciliates incubated with and without chitin was 45.0 and 30.5 pmol VFA per protozoan, respectively, the molar proportion of particular acids remaining unchanged.

Major and minor compounds in a traditional Mexican spirit, young mezcal from Agave angustifolia and Agave potatorum, were characterised using gas chromatography and solid phase microextraction-gas chromatography-mass spectrometry. A large variability in both mezcal samples was detected in the content of methanol, higher alcohols, acetic acid, and ethyl acetate. However, their values were below the maximum concentration permitted by the Mexican Standards. The minor compounds identified by mass spectrometry included alcohols, esters, ketones, acids, and furanes. The similarities found between mezcal from Agave angustifolia and Agave potatorum may be due to their processing methods. In addition, mezcals contain unique compounds that can be used as markers to identify the products of different origins.

The present study examined the impact of Enterococcus faecium on morphological development and production of short-chain fatty acids in the digestive tract of gnotobiotic piglets during milk nutrition and weaning. The experiment was carried out on 18 gnotobiotic piglets. The feeding ration consisted of autoclaved milk substitute (Sanolac Ferkel, Germany). From the first day of life a probiotic strain of Enterococcus faecium was administered continually at a dose of 2 mL of inoculum. The animals were weaned on Day 28. Gastrointestinal tract was collected from 18 gnotobiotic piglets slaughtered at three hours after birth and at the age of 2, 7, 14, 21, 28 and 35 days. The level of short-chain fatty acids was determined in the contents of jejunum, ileum and colon. Samples of intestinal mucosa were subjected to morphological analysis. We characterized regional variations in morphological and functional responses of the small intestine. The jejunal part of the intestinal tract was characterized by relatively short crypts, extremely long villi and narrow lamina propria which contained only few cells up to Day 14 of life. Morphological examination showed that jejunal and ileal villi were significantly lower at 21 days of age. Depending on age, the concentration of both acetoacetic acid and acetic acid was higher in the jejunal contents. The difference was significant on Day 7 of age for acetoacetic acid and on Day 28 of age for acetic acid. The concentration of acetic acid in the colonal content of gnotobiotic piglets was significantly higher on Day 7 and 21 of age. Postnatal bacterial colonization patterns may have long-term effects on intestinal health and development.