Effect of microbial composition on thermophilic acid fermentation

A continuous thermophilic acid fermentation experiment was performed using kitchen garbage to investigate relationship between microbial composition and products in acid fermentation processes. Hydrogen fermentation occurred under the longer SRT condition, and when SRT was set at shorter, lactate production increased, and butyrate and hydrogen production decreased. Simultaneously, microbial composition change from Clostridium spp. to Bacillus spp., especially Bacillus coagulans was observed using random cloning method. Clear relationship between B. coagulans ratio and lactate concentration was obtained, but random cloning method is time and cost consuming, and not preciously quantitative. Applicability of real-time PCR quantification to monitor change in B. coagulans in kitchen garbage fermentation was verified. Acid fermentation produces many kinds of organic acids such as lactate, butyrate and acetate, and hydrogen gas, and similar operational conditions are proposed for hydrogen and lactate fermentations. Real-time PCR quantification methods would be useful for developing a new monitoring tool for acid fermentation, especially with complex substrates, where many kinds of bacteria compete with each other in the same reactor

Changes in tomato ovary transcriptome demonstrate complex hormonal regulation of fruit set

Item does not contain fulltext* Plant hormones are considered to be important mediators of the fruit developmental signal after pollination. The role of phytohormones in tomato (Solanum lycopersicum) fruit set was investigated here. * Transcriptome analysis of ovaries was performed using two complementary approaches: cDNA-amplified fragment length polymorphism (AFLP) and microarray analysis. * The gene expression profiles obtained suggest that, in addition to auxin and gibberellin, ethylene and abscisic acid (ABA) are involved in regulating fruit set. Before fruit development, many genes involved in biotic and abiotic responses are active in the ovary. In addition, genes involved in ethylene and ABA biosynthesis were strongly expressed, suggesting relatively high ethylene and ABA concentrations before fruit set. Induction of fruit development, either by pollination or by gibberellin application, attenuated expression of all ethylene and ABA biosynthesis and response genes within 24 h. * It is proposed that the function of ABA and ethylene in fruit set might be antagonistic to that of auxin and gibberellin in order to keep the ovary in a temporally protected and dormant state; either to protect the ovary tissue or to prevent fruit development before pollination and fertilization occur.17 p