Blue-light-activated histidine kinases: two-component sensors in bacteria

Histidine kinases, used for environmental sensing by bacterial two-component systems, are involved in regulation of bacterial gene expression, chemotaxis, phototaxis, and virulence. Flavin-containing domains function as light-sensory modules in plant and algal phototropins and in fungal blue-light receptors. We have discovered that the prokaryotes Brucella melitensis, Brucella abortus, Erythrobacter litoralis, and Pseudomonas syringae contain light-activated histidine kinases that bind a flavin chromophore and undergo photochemistry indicative of cysteinyl-flavin adduct formation. Infection of macrophages by B. abortus was stimulated by light in the wild type but was limited in photochemically inactive and null mutants, indicating that the flavin-containing histidine kinase functions as a photoreceptor regulating B. abortus virulence.     

Compression form-fitted athletic wear: Pressure performance,moisture management properties under different tension ratios,and corresponding psychophysical responses

Pressure performance and moisture management properties (MMP) of compression form-fitted athletic wear (CFA) play important role in achieving their mechanical functionality, wearing comfort, and physiological health for athletes during intensive exercises. Based on the 5Ps model, pressure and liquid moisture transfer attributes and their resultant subjective perceptions are analyzed and discussed through adopting objective and subjective measuring methods in this study. The MMP of eight types of fabric specimens were evaluated when the specimens were stretched at tension ratios of 0 %, 10 % and 20 % by applying an innovatively improved moisture management test method. Most of the tested specimens presented satisfied MMP when tested in a relaxed state. Testing under tension status significantly influenced the MMP of the tested specimens. The changes were mainly reflected in the prolonged wetting time, the increased absorption rates at the skin-contacted fabric surface, the reduced wetted radius and spreading speed at outer side of fabric, and the weakened one-way transfer properties. The tested fabrics with stretch of 20 % showed, in general, better performances in MMP than those with a stretch of 10 %. Pressure characteristic values ranging from 1679.88 to 2752.89 Pa on average were extracted from the different six pressure zones around the tested athletes’ bodies. Our improved MMT test method provides a new approach to study the fabric MMP when fabrics are under different tensions. Five sensory dimensions were used to analyze psychophysical responses to the physical stimulus of pressure and MMP, which revealed complex interactive mechanisms existing between pressure action, moisture transfer attributes and comfort perceptions related to compression athletic wear.     

Mycotoxins in pet food: a review on worldwide prevalence and preventative strategies

Mycotoxins contaminate cereal grains worldwide, and their presence in pet food has been a potential health threat to companion animals. Aflatoxins, ochratoxin A, and Fusarium mycotoxins have been found in both raw ingredients and final products of pet food around the globe. Aflatoxin, a hepatotoxin and carcinogen, has caused several food poisoning outbreaks in dogs, and aflatoxin content is regulated in pet food in many countries. Ochratoxin A and Fusarium mycotoxins including trichothecenes, zearalenone, and fumonisins may have chronic effects on the health of companion animals. Grain processing, sampling error, analytical methods, conjugated mycotoxins, storage conditions, and synergistic interactions are common challenges faced by the pet food industry. Food-processing techniques such as sieving, washing, pearling, ozonation, and acid-based mold inhibition reduce the mycotoxin content of cereal grains. Dietary supplementation with large neutral amino acids, antioxidants, and omega-3 polysaturated fatty acids as well as inclusion of mycotoxin-sequestering agents and detoxifying microbes may ameliorate the harmful effects of mycotoxins in contaminated pet food.     

Photoprotection of Beauveria bassiana: Testing simple formulations for control of the coffee berry borer

The entomopathogenic fungus, Beauveria bassiana is considered to be one of the few natural enemies available for use against the coffee berry borer. In an attempt to enhance the efficacy of this pathogen, a range of concentrations of 22 substances was tested in simple laboratory tests using natural sunlight or a UV light source. Unprotected B. bassiana spores were almost completely inactivated by exposure to 60 min of direct sunlight or 20 s of UV light of 302 nm wavelength. Seven of the 22 substances tested showed little or no photoprotective properties and eight of the substances appeared directly detrimental to spore germination. Of the remainder, sucrose, yeast, yeast extract, uric acid, casein, and molasses had limited photoprotective properties. The most effective substances tested were egg albumen and skimmed milk powder which could extend the persistence of B. bassiana spores by a factor of almost three. A mixture of 3% (w/v) albumen and 4% (w/v) milk powder gave the highest degree of spore protection per unit cost. Young coffee plants sprayed with this mixture did not suffer any significant phytotoxic effects. A field trial, involving two applications of spores with or without the milk and albumen mixture, failed to show that improved spore persistence resulted in increased coffee berry borer control. Very lowlevels of pest infestation observed in field plots together with unusual, unfavourable weather conditions may have accounted for this unexpected result.