Isolation, Identification, Screening and Fermentation Process Optimization of Bacillus Producing High Antimicrobial Lipopeptide

In order to screen out Bacillus sp. with high production of antimicrobial lipopeptide and determine its optimal fermentation conditions, the study isolated and identified antimicrobial lipopeptide-producing Bacillus sp. strains from traditional fermented soybean paste, and adopted orthogonal test to investigate how lipopeptide production by Bacillus sp was affected by fermentation conditions, such as fermentation inoculum amount, fermentation filling volume, fermentation time and fermentation temperature. The results showed that 27 strains of Bacillus sp. were isolated and screened out from 9 portions traditional fermented soybean paste of the Northeast, among which 6 strains were identified by 16S rDNA as having the genes sfp, fenB and ituA for synthesizing lipopeptide. According to the determination of lipopeptide yield and inhibition effect, Bacillus subtilis SN-20 and Bacillus amyloliquefaciens SN-46 showed excellent performance with the yield of 106 and 72 mg of lipopeptide per unit, and strong inhibition effect on both gram-positive and negative indicator bacteria. The optimal fermentation process of Bacillus subtilis SN-20 was found to be 3% inoculum, 20% fermentation filler, 36 h fermentation time and 32 ℃. The optimal fermentation process of Bacillus subtilis SN-46 was 2% inoculum, 40% fermentation filler, 24 h fermentation time and 32 ℃. Under these conditions, the unit biomass yields of lipopeptides for the two strains of Bacillus before optimization were 106.11 and 76.23 mg/g, respectively. After optimization, they increased by 21.85% and 23.84%, respectively. The study results effectively increased the production of antimicrobial lipopeptides from Bacillus

Whole Genome Sequencing of Bacillus subtilis SNBS-3 and Prediction of Its Antimicrobial Substances

As an extension of the previous research, this study aimed to comprehensively characterize the genome of Bacillus subtilis SNBS-3. Illumina second-generation sequencing technology and the third-generation high-throughput Pacbio sequencing platform were used for whole-genome sequencing of B. subtilis SNBS-3 isolated from traditional bean paste to obtain the key information of genome characteristics, gene function annotation and classification, phylogenetic evolution, and secondary metabolites. The results showed that the genome of SNBS-3 was a closed circular DNA of 4 076 387 bp in length containing 4 000 protein-coding genes. A total of 3 209, 2 824, 2 560, 147, 12 and 4 functional genes were annotated in the Clusters of Orthologous Groups (COG), Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), Carbohydrate-Active Enzymes (CAZyme), Comprehensive Antibiotic Resistance Database (CARD) and Virulence Factor Database (VFDB), respectively. Using the online software AntiSMASH and Bagel4, we found that it contained genes related to the synthesis of surfactin, mycosubtilin, plipastatin, bacilysin and bacillaene, as well as a complete gene cluster for the synthesis of the bacteriocin subtilosin A. Based on the results of antimicrobial test and proteinase K test, it was hypothesized that B. subtilis SNBS-3 had the ability to synthesize subtilosin A. In conclusion, the whole genome sequencing results of B. subtilis SNBS-3 show that it can produce a variety of bacteriostatic substances and thus have biocontrol potential. The results from this study provide a theoretical basis for further development and application of various bacteriostatic substances including the bacteriocin subtilosin A

Evolutionary and Expression Analysis of MOV10 and MOV10L1 Reveals Their Origin, Duplication and Divergence

MOV10 and MOV10L1 both encode ATP-dependent RNA helicases. In mammals, MOV10 and MOV10L1 participate in various kinds of biological contexts, such as defense of RNA virus invasion, neuron system, germ cell and early development. However, mov10 and mov10l1 in zebrafish are obscure and the evolutionary relationships of mov10 among different species remain unclear. In this study, we found MOV10 and MOV10L1 had some variations despite they possessed the conserved feature of RNA helicase, however, they may originate from a single ancestor although they shared limited homology. A single MOV10L1 gene existed among all species, while MOV10 gene experienced lineage-specific intra-chromosomal gene duplication in several species. Interestingly, the mov10 gene expanded to three in zebrafish, which originating from a duplication by whole genome specific duplication of teleost lineage followed by a specific intra-chromosome tandem duplication. The mov10 and mov10l1 showed distinct expression profiles in early stages, however, in adult zebrafish, three mov10 genes exhibited similar diverse expression patterns in almost all tissues. We also demonstrated mov10 genes were upregulated upon virus challenge, highlighting they had redundant conserved roles in virus infection. These results provide valuable data for the evolution of MOV10 and MOV10L1 and they are important to the further functional exploration

Implantable Thin Film Devices as Brain-Computer Interfaces: Recent Advances in Design and Fabrication Approaches

Remarkable progress has been made in the high resolution, biocompatibility, durability and stretchability for the implantable brain-computer interface (BCI) in the last decades. Due to the inevitable damage of brain tissue caused by traditional rigid devices, the thin film devices are developing rapidly and attracting considerable attention, with continuous progress in flexible materials and non-silicon micro/nano fabrication methods. Therefore, it is necessary to systematically summarize the recent development of implantable thin film devices for acquiring brain information. This brief review subdivides the flexible thin film devices into the following four categories: planar, open-mesh, probe, and micro-wire layouts. In addition, an overview of the fabrication approaches is also presented. Traditional lithography and state-of-the-art processing methods are discussed for the key issue of high-resolution. Special substrates and interconnects are also highlighted with varied materials and fabrication routines. In conclusion, a discussion of the remaining obstacles and directions for future research is provided

Biofilm tolerance, resistance and infections increasing threat of public health

Microbial biofilms can cause chronic infection. In the clinical setting, the biofilm-related infections usually persist and reoccur; the main reason is the increased antibiotic resistance of biofilms. Traditional antibiotic therapy is not effective and might increase the threat of antibiotic resistance to public health. Therefore, it is urgent to study the tolerance and resistance mechanism of biofilms to antibiotics and find effective therapies for biofilm-related infections. The tolerance mechanism and host reaction of biofilm to antibiotics are reviewed, and bacterial biofilm related diseases formed by human pathogens are discussed thoroughly. The review also explored the role of biofilms in the development of bacterial resistance mechanisms and proposed therapeutic intervention strategies for biofilm related diseases