Acid tolerant bacterium Bacillus amyloliquefaciens MBNC retains biocontrol efficiency against fungal phytopathogens in low pH

Soil pH conditions have important consequences for microbial community structure, their dynamics, ecosystem processes, and interactions with plants. Low soil pH affects the growth and functional activity of bacterial biocontrol agents which may experience a paradigm shift in their ability to act antagonistically against fungal phytopathogens. In this study, the antifungal activity of an acid-tolerant soil bacterium Bacillus amyloliquefaciens MBNC was evaluated under low pH and compared to its activity in neutral pH conditions. Bacterial supernatant from 3-day-old culture (approximately 11.2 × 10⁸ cells/mL) grown in low pH conditions was found more effective against fungal pathogens. B. amyloliquefaciens MBNC harboured genes involved in the synthesis of secondary metabolites of which surfactin homologues, with varying chain length (C11-C15), were identified through High-Resolution Mass Spectroscopy. The pH of the medium influenced the production of these metabolites. Surfactin C15 was exclusive to the extract of pH 4.5; production of iturinA and surfactin C11 was detected only in pH 7.0, while surfactin C12, C13 and C14 were detected in extracts of both the pH conditions. The secretion of phytohormones viz. indole acetic acid and gibberellic acid by B. amyloliquefaciens MBNC was detected in higher amounts in neutral condition compared to acidic condition. Although, secretion of metabolites and phytohormones in B. amyloliquefaciens MBNC was influenced by the pH condition of the medium, the isolate retained its antagonistic efficiency against several fungal phyto-pathogens under acidic condition.

Steroid and metabolic hormonal profile of porcine serum vis-à-vis ovarian follicular fluid

Aim:

This study was conducted to understand whether serum level of the steroid and metabolic hormones may be indicative of their level in ovarian follicular fluid (FF) in porcine, and its influence on fertility.

Materials and Methods:

Ovaries from pigs (n=32) of two genetic groups, namely, native (Ghungroo; n=16) and crossbred (Hampshire × Ghungroo; n=16) were collected. Both the genetic groups comprised gilts (n=8) and sows (n=8), and sows were in luteal phase of estrus cycle. FF was aspirated from small, medium and large follicles, and centrifuged for the collection of supernatant for further analysis. Blood samples were collected from the same animals, and serum was separated. Hormones, namely, cortisol, T3, T4 and testosterone were estimated by radioimmunoassay. Two-way ANOVA was used for analysis of data considering genetic background (native or crossbred), stage of reproductive life (gilt or sow), and source of sample (serum or FF) as fixed effects.

Results:

It was observed that all the hormones except cortisol differed significantly (p<0.01) based on genetic background. Stage of reproductive life and source of sample did not affect the studied hormonal level. Within the genetic groups, stage of reproductive life influenced T3 (p<0.01), cortisol (p<0.05) and testosterone (p<0.01) level in crossbred pigs as compared to T3 (p<0.01) only in native pigs. The level of T3 in serum, as well as FF, was higher (p<0.01) in Ghungroo gilts compared to sows. However, a reverse of this was observed in the case of crossbred pigs. The level of cortisol (p<0.05) and testosterone (p<0.01) was higher in crossbred sows than gilts in both serum and FF.

Conclusion:

The study revealed that serum level of the steroid and metabolic hormones is indicative of their level in the ovarian FF. Further, varying level of steroid and metabolic hormones in pigs based on genetic background may be due to variation in body size, rate of energy metabolism and stage of (re)productive life.

The challenge of viral snRNPs

Some gammaherpesviruses encode nuclear noncoding RNAs (ncRNAs) that assemble with host proteins. Their conservation and abundance implies that they serve important functions for the virus. This paper focuses on our studies of three classes of nuclear noncoding herpesvirus RNAs. (1) EBERs 1 and 2 are expressed by Epstein-Barr virus in latent infection of human B lymphocytes. Recent studies revealed three sites on EBER1 that associate with ribosomal protein L22. In addition, heterokaryon assays have definitively shown that both EBERs are confined to the nucleus, arguing that their contribution to viral latency is purely nuclear. (2) HSURs 1-7 are U RNAs encoded by Herpesvirus saimiri, which causes aggressive T-cell leukemias and lymphomas. Comparison of monkey T cells transformed with wild-type or mutant virus lacking HSURs 1 and 2 revealed significant changes in host mRNAs implicated in T-cell signaling. (3) PAN is a 1-kb polyadenylated RNA that accumulates in the nucleus of Kaposi's sarcoma-associated herpesvirus lytically infected cells. A novel element, the ENE, is essential for its high accumulation. Recent results indicate that the ENE functions to counteract poly(A)-dependent RNA degradation, which we propose contributes to nuclear surveillance of mRNA transcripts in mammalian cells. Continuing studies of these viral RNAs will provide insights into both cellular and viral gene expression.