Small double-stranded RNA with anti-HIV activity abundantly produced by Bacillus subtilis MTCC5480 isolated from fermented soybean

Bacillus subtilis partially inhibits African swine fever virus infection in vivo and in vitro based on its metabolites arctiin and genistein interfering with the function of viral topoisomerase II

IMPORTANCE

African swine fever virus (ASFV) is a highly fatal swine disease that severely affects the pig industry. Although ASFV has been prevalent for more than 100 years, effective vaccines or antiviral strategies are still lacking. In this study, we identified four Bacillus subtilis strains that inhibited ASFV proliferation in vitro. Pigs fed with liquid biologics or powders derived from four B. subtilis strains mixed with pellet feed showed reduced morbidity and mortality when challenged with ASFV. Further analysis showed that the antiviral activity of B. subtilis was based on its metabolites arctiin and genistein interfering with the function of viral topoisomerase II. Our findings offer a promising new strategy for the prevention and control of ASFV that may significantly alleviate the economic losses in the pig industry.

A method for high-concentration agarose gel preparation and its application in high-resolution separation of low-molecular-weight nucleic acids and proteins

Separation of nucleic acids and proteins using gels has always been a crucial part of molecular biology research. For low-molecular-weight nucleic acids and proteins, low- and medium-concentration agarose gels cannot achieve the high resolution as polyacrylamide gels. We found that 6 %-14 % high-concentration agarose gels (HAGs) could be easily dissolved in an autoclave and the vertical gel cast can be effortlessly filled using an easy-made plastic box. Coupled with the improved buffer condition, HAG electrophoresis resulted in a good resolution of DNA and protein bands. With conventional TBE buffer plus 0.2 % NaCl, DNA fragments that differ by 2-5-bp within the 50-200-bp size range can be resolved on 6 %-8 % HAGs. By using TBE without NaCl, DNA fragments that differ by 2-bp or 2-nt within the 10-100-bp size range can be well resolved on >8 % HAGs. Using a buffer system comprising 1 M Tris-Cl for gel preparation, 0.2 M Tris-Cl/0.2 % SDS as upper tank buffer, and 0.2 M Tris-Cl as the lower tank buffer, HAGs achieved good molecular weight separation of total bacterial and plant proteins in the 10-200 kDa range. In conclusion, we developed a method for HAG preparation and electrophoresis of low-molecular-weight nucleic acids and proteins.

Selective extracellular secretion of small double-stranded RNA by Tetragenococcus halophilus

Small double-stranded RNAs (dsRNAs) abundantly produced by lactic acid bacteria demonstrate immunomodulatory activity and antiviral protective immunity. However, the extracellular secretion of dsRNA from lactic acid bacteria and their compositional and functional differences compared to the intracellular dsRNA is unknown. In this study, we compared the intracellular and secreted extracellular dsRNA of the lactic acid bacteria, Tetragenococcus halophilus, commonly present in fermented foods, by growing in RNA-free and RNase-free media. We used RNA deep sequencing and in-silico analysis to annotate potential regulatory functions for the comparison. A time series sampling of T. halophilus culture demonstrated growth phase-dependent dynamics in extracellular dsRNA secretion with no major change in the intracellular dsRNA profile. The RNA deep sequencing resulted in thousands of diverse dsRNA fragments with 14-21 nucleotides in size from T. halophilus culture. Over 70% of the secreted extracellular dsRNAs were unique in their sequences compared to the intracellular dsRNAs. Furthermore, the extracellular dsRNA abundantly contains sequences that are not T. halophilus genome encoded, not detected intracellularly and showed higher hits on human transcriptome during in-silico analysis, which suggests the presence of extrachromosomal mobile regulatory elements. Further analysis showed significant enrichment of dsRNA target genes of human transcriptome on cancer pathways and transcription process, indicating the extracellular dsRNA of T. halophilus is different not only at the sequence level but also in function. Studying the bacterial extracellular dsRNA is a promising area of future research, particularly for developing postbiotic fermented functional foods and understanding the impact of commensal gut bacteria on human health.

Diversity of beneficial microorganisms and their functionalities in community-specific ethnic fermented foods of the Eastern Himalayas

The Eastern Himalayan regions of India, Nepal and Bhutan have more than 200 varieties of unsurpassed ethnic fermented foods and alcoholic beverages, which are lesser known outside the world. However, these ethnic foods are region- and community-specific, unique and some are exotic and rare, which include fermented vegetables, bamboo shoots, soybeans, cereals, milk (cow and yak), meats, fishes, and cereal-based alcoholic beverages and drinks. Ethnic communities living in the Eastern Himalayas have invented the indigenous knowledge of utilization of unseen microorganisms present in and around the environment for preservation and fermentation of perishable plant or animal substrates to obtain organoleptically desirable and culturally acceptable ethnic fermented food and alcoholic beverages. Some ethnic fermented products and traditionally prepared dry starters for production of alcoholic beverages of North Eastern states of India and Nepal were scientifically studied and reported till date, and however, limited publications are available on microbiological and nutritional aspects of ethnic fermented foods of Bhutan except on few products. Most of the beneficial microorganisms isolated from some ethnic fermented foods of the EH are listed in microbial food cultures (MFC) safe inventory. This study is aimed to review the updates on the beneficial importance of abundant microbiota and health-promoting benefits and functionalities of some ethnic fermented foods of the Eastern Himalayan regions of North East India, Nepal and Bhutan.

Bioactive phytocompound mulberroside C and endophytes of Morus alba as potential inhibitors of HIV-1 replication: a mechanistic evaluation

OBJECTIVES

Despite considerable advancement in antiretroviral therapy, development of safe, effective, and multi-targeted drugs for HIV still remains a big challenge. Endophytes are untouched and, hence, an important and novel sources in drug discovery endeavours. The present study was conducted to identify the anti-HIV compounds from Morus alba and endophytes isolated from it.

METHODS

The extracts of isolated endophytes were screened using high-performance liquid chromatography (HPLC). Further, all samples were analysed for their cytotoxicity using a thiazolyl blue tetrazolium bromide assay. Subsequently, anti-HIV activity was performed using cell-based and cell-free assay. At the end, potential endophytes were identified using gene sequencing.

RESULTS

A total of 27 endophytes were isolated from the eight stem bark samples of M. alba. Of the 27 endophytes, extracts of total of four endophytes showed a profile similar to the M. alba plant when analysed by HPLC. Further experimentation with extracts of these four endophytes, along with an extract of M. alba stem bark and its bioactive molecule, mulberroside C, revealed that all these six samples have good inhibitory potential for HIV. Among them, mulberroside C and two endophytic fungal extracts showed very potent anti-HIV activity. Subsequently, mechanistic studies at the molecular level showed that out of six test samples, three acted as protease inhibitors. Further, all four potential endophytes were identified using gene sequencing.

CONCLUSIONS

The overall findings of these studies can help in the development of a novel anti-HIV candidate from mulberroside C, an extract of stem bark of M. alba and extracts of these endophytes. However, further validation and clinical studies are required to develop an anti-HIV drug.