Trans splicing of mRNA precursors in vitro

Two exon segments from two separate RNA molecules can be joined in a trans splicing process. In trans splicing reactions, an RNA molecule containing an exon, a 5' splice site, and adjacent intron sequences was mixed with an RNA molecule containing an exon, a 3' splice site, and adjacent intron sequences. The efficiency of trans splicing of these two RNAs increased if the two termini of the intervening sequences were paired in a short RNA duplex. However, trans splicing of two RNA molecules with no significant complementarity was also observed. These results strongly suggest that significant secondary structures within intervening sequences could affect the splicing of flanking exons. Similarly, RNAs that are complementary to segments within the intervening sequences could potentially regulate the selection of splice sites. Finally, some organisms might use trans splicing to distribute a single exon to many different mRNAs.     

Detection of false-positives among total and fecal coliform counts by factorial analysis of correspondence

Application of an analysis of correspondence to the biochemical characteristics of total and fecal coliforms isolated in the Ivory Coast permitted us to separate two small clusters of isolates different from the main clusters, which included isolates from human and animal feces. The isolates grouped in the small clusters were from water samples. An analysis of the biochemical characteristics which permitted the segregation of the "water-specific" isolates from the main clusters indicates that water-specific total coliforms were citrate positive, indole negative, and amygdaline positive. Water-specific fecal coliforms were either citrate positive, indole negative, amygdaline positive, and inositol negative or indole negative, amygdaline positive, and inositol positive. Any isolates not fitting the above patterns could be considered of fecal origin. If this observation is confirmed under temperate climates and for a greater number of isolates, these simple tests could be used to confirm the fecal origin of coliforms.     

Kinetics of microbial growth on pentachlorophenol

Batch and fed-batch experiments were conducted to examine the kinetics of pentachlorophenol utilization by an enrichment culture of pentachlorophenol-degrading bacteria. The Haldane modification of the Monod equation was found to describe the relationship between the specific growth rate and substrate concentration. Analysis of the kinetic parameters indicated that the maximum specific growth rate and yield coefficients are low, with values of 0.074 h-1 and 0.136 g/g, respectively. The Monod constant (Ks) was estimated to be 60 micrograms/liter, indicating a high affinity of the microorganisms for the substrate. However, high concentrations (KI = 1,375 micrograms/liter) were shown to be inhibitory for metabolism and growth. These kinetic parameters can be used to define the optimal conditions for the removal of pentachlorophenol in biological treatment systems.     

Relation of coenzyme F420 to the activity of methanogenic microorganisms

Summary The relationship between the coenzyme F₄₂₀ content and the activity of methanogenic microorganisms was investigated under different cultivation conditions in anaerobic reactors. The coenzyme F₄₂₀ concentration depends on the substrate used and the cultivation conditions. Coenzyme F₄₂₀ appears not to be a measure of the total methanogenic activity but rather a measure of the amount of methanogenic microorganisms in mixed anaerobic cultures.     

Study of the effect of β-1,3-glucanase fromBasidiomycete QM 806 on yeast extract production

Summary Cell free supernatants, containing -1,3-glucanase fromBasidiomycete QM 806, dramatically augmented the effect of papain on yeast autolysis. This enables the process time to be significantly reduced and/or the yield of extract to be substantially increased.