The antibiotic resistance and virulence of Acinetobacter baumannii are increasingly serious. Studies have shown that the CRISPR-Cas system in A. baumannii attenuates the antibiotic resistance and virulence, while the effects of CRISPR-Cas system components on A. baumannii remain unclear. [Objective] Investigation of the role of components of the CRISPR-Cas system in the modulation of bacterial drug resistance and virulence in A. baumannii. [Methods] The impact of cas1 overexpression on bacterial growth, serum resistance, bacterial drug resistance, biofilm formation ability, and survival rate of mice in a mouse model of bacterial infection was investigated by constructing cas1 overexpression strains and corresponding with them to detect the aforementioned changes. [Results] The resistance of the bacterial strain AB26::cas1 to 22 commonly used antibiotics was determined using the paper diffusion method. Of these antibiotics, six were found to have an effect on the strain, causing it to change from resistant to sensitive. The capacity of the bacterial strain AB26::cas1 to form biofilms was evaluated through the use of crystal violet staining, which revealed a reduction in biofilm formation ability when compared to the AB26 strain. The intraperitoneal injection of the infected mice model demonstrated that no mortality occurred in the AB26::cas1 strain in vivo infected group in comparison to the AB26 strain in vivo infected group. The fluorescence quantitative PCR assay demonstrated a reduction in mRNA expression of the majority of resistance and toxicity genes. The survival assay, which involved incubating normal human serum with inactivated serum, revealed no statistically significant difference in serum resistance between the wild strains and the overexpression strains. [Conclusion] The cas1 gene, derived from strain AB43, was observed to exert an inhibitory effect on the drug resistance and biofilm-forming ability of A. baumannii, as well as the pathogenicity of the bacteria in mice.

chitooligosaccharide (COS) are degradation products of chitin or chitosan, demonstrating good biocompatibility, degradability, non-toxicity, and multiple bioactivities. COS have been widely used in food, cosmetics, composite materials, wastewater treatment, and biomedical industries. Currently, researchers mainly use physical, chemical, and biological enzyme methods to prepare COS. Physical and chemical methods have large limitations, and it is difficult to synthesize the target products with specific requirements in an efficient and green way. Bio-enzymatic preparation of COS shows a mild, controllable, and environmental friendly reaction process, overcoming the drawbacks of physical and chemical methods. The purity of COS can be improved by separation and purification techniques such as membrane separation, gel filtration chromatography, CM-SephadexC-25 ion-exchange column chromatography, and immobilized metal affinity chromatography. This review summarized the research progress in COS preparation using bio-enzymatic technology, aiming to lay theoretical foundation for high-quality industrial COS preparation. It also gave an overview of the structure, properties, and application of COS, contributing for the research on COS preparation and isolation.

[Objective] To elucidate the structural and functional characteristics of the gut microbiota of Trypoxylus dichotomus larvae and isolate cellulose-degrading bacteria. [Methods] Metagenomic sequencing was employed to analyze the structure and functions of the gut microbiota. Cellulose-degrading bacteria were isolated and screened from the larval gut with carboxymethyl cellulose (CMC) as the sole carbon source. The strains were identified based on morphological characteristics and molecular evidence. [Results] The gut microbiota was dominated by bacteria, which accounted for 81.3%. At the phylum level, Firmicutes (45.8%) and Bacteroidota (20.3%) were the dominant phyla. The top three abundant genera were Clostridium (3.90%), Bacteroidia (3.52%), and Dysgonomonas (2.41%). The functional analysis of metagenome data revealed that the genes of the gut microbiota were mainly associated with carbohydrate, amino acid, and energy metabolism. The annotation in the Kyoto Encyclopedia of Genes and Genomes (KEGG) revealed that the genes related to carbohydrate metabolism were predominant. The annotation in the carbohydrate-active enzyme database (CAZy) indicated that 48 856 (7.43%) genes were successfully annotated to 344 carbohydrate metabolism enzyme families, with glycoside hydrolase (GH, 48.67%) being the most dominant enzyme family in the gut bacteria. Among the top ten functionally abundant enzymes, six belonged to the GH family. Additionally, three strains of cellulose-degrading bacteria, TRC-3 (Bacillus subtilis), TRC-5 (B. subtilis), and TRC-6 (B. safensis), were isolated from the gut. TRC-3 exhibited stronger activities of filter paper enzyme, endoglucanase, exoglucanase, and β-glucosidase. [Conclusion] The gut microbiota of Trypoxylus dichotomus larvae exhibits high diversity and complexity, carrying a large number of genes encoding carbohydrate-active enzymes and harboring rich cellulose-degrading bacteria.

[Objective] To study the mechanism of plant growth-promoting rhizobacterium (PGPR) in the rhizosphere of sea rice and the effects of PGPR on the growth of terrestrial crops under salt stress. [Methods] The salt tolerance, alkali-reducing ability, and plant growth-promoting effect were determined for 15 bacterial strains isolated from the rhizosphere soil of sea rice. Highly active strains were selected for species identification and construction of a consortium. The effect of the consortium on the seed germination of mung bean was verified. [Results] The 15 strains of PGPR were moderately halophilic and strain SL-1 was an extreme halophile among them. Four halophilic strains had alkali tolerance and alkali-degrading effect, among which strain SH-3 had the highest alkali-degrading effect (16.83%). These four strains demonstrated different plant growth-promoting effects. All the strains could produce extracellular polymers (EPS), and strain SH-3 had the highest EPS production (0.47 g/g). The strains were capable of producing indole-3-acetic acid (IAA), with the yields between 0.70 mg/L and 1.48 mg/L. Three highly active strains SL-1, SM-1 and SH-3 belonging to Bacillus and Enterobacter were used to construct a consortium. Seed germination experiments showed that PGPR and the consortium promoted the seed germination of mung bean under salt stress. Moreover, the consortium showcased stronger promoting effect on seed germination than single PGPR. Compared with the control group, the consortium was more effective at the salt concentration of 15 g/L. Specifically, it improved the root length, germination rate, and simplified vitality index, while decreasing the relative salt injure rate from 80.53% to 18.95% and increasing the salt tolerance threshold of mung bean seeds from 10 g/L to 15 g/L. The data indicated that strains of the consortium coordinated to promote the seed germination of mung bean. The correlation analysis showed a strong positive correlation between EPS and IAA, both of which promoted the seed germination, growth, and development of mung bean under salt stress. [Conclusion] Strains SL-1, SM-1 and SH-3 had strong halophilicity, alkali tolerance, and abilities of degrading alkali, producing EPS and IAA, and promoting plant growth. The findings provide a scientific basis for the rational development and utilization of soil microbial resources and the improvement of saline-alkali soil environment.

Metagenomics has enriched our understanding about the composition and functions of digestive tract microbiota in animals. Currently, metagenomic sequencing can generally achieve the classification rate of species between 15% and 45% at the read level. Therefore, improving the alignment rate of microbial reads in metagenomics can help to further mine microbial information from metagenome data. [Objective] To enhance the classification ability for digestive tract microbiota in ruminants by extending the Kraken2 standard database, thereby deeply mining the microbial information from metagenome data. [Methods] A total of 14 827 metagenome-assembled genomes (MAGs) of the rumen fluid, feces, and digestive tracts of cattle, sheep, and goats were collected. After quality control and filtering, 3 095 species-level genome bins (SGBs) were retained. These SGBs were integrated into the Kraken2 standard database following taxonomic classification and functional prediction, and the classification effect was evaluated. [Results] In the genome taxonomy database (GTDB), the 3 095 SGBs were identified as bacteria belonging to 782 genera of 28 phyla (3 053 SGBs) and archaea belonging to 8 genera of 2 phyla (42 SGBs). The functional prediction based on eggNOG annotated the SGBs into 26 clusters of orthologous groups of proteins (COGs). The Kyoto encyclopedia of genes and genomes (KEGG) enrichment categorized the top 25 ortholog groups (KO entries) into 14 pathways. The prediction of carbohydrate-active enzymes (CAZy) showed that 593 SGBs were annotated into six classes of CAZymes: auxiliary activities (AA), carbohydrate esterases (CE), glycosyltransferases (GT), carbohydrate-binding modules (CBM), glycoside hydrolases (GH), and polysaccharide lyases (PL). Among them, GH was the most common class. The addition of 3 095 SGBs to the Kraken2 standard database (May 2024) increased the number of species in the database by 5.00%, extending the size from 87.2 Gb to 98.2 Gb. Furthermore, a study about the effect of diet fiber-to-concentrate ratio on the rumen microbiota of Holstein cows by metagenomics was reassessed, which showed that the integration of SGBs into the database raised the species alignment rate of rumen metagenome reads from (19.35±1.81)% to (51.04±2.05)%. The principal component analysis results at the species level indicated that the extended database enhanced the ability to distinguish rumen microbiota structures under two different diet fiber-to-concentrate ratios. The linear discriminant analysis effect size results indicated that the microbial markers for low-fiber and high-fiber diets were Xylanibacter ruminicola and Aristaeella hokkaidonensis, respectively, in the standard database, whereas they were Prevotella sp. 902800365 and Prevotella sp. 900316445, respectively, in the extended database. [Conclusion] In summary, introducing SGBs to extend the Kraken2 standard database can increase species coverage and improve the alignment rate of species at the metagenome read level, thereby enhancing the understanding of microbial information in metagenome data.

[Objective] To explore the effects of strain CDWB36 and its metabolite pyrroloquinoline quinone (PQQ) on the drought resistance and growth of pepper, so as to provide efficient strain resources for the development and utilization of multifunctional microbial agents. [Methods] A strain CDWB36 was identified based on the morphological characteristics and the 16S rRNA gene-based phylogenetic tree. HPLC and spectroscopy were employed to detect PQQ. The fermentation conditions were optimized by single factor tests with PQQ production as the indicator. The effects of the PQQ-containing microbial agent on the growth, physio-biochemical characteristics, soil nutrients, and rhizosphere microbial community structure of pepper under drought stress were determined by pot experiments. [Results] Strain CDWB36 was identified as Acinetobacter calcoaceticus and it had the ability to produce PQQ. The optimum conditions of strain CDWB36 for producing PQQ were 10 g/L yeast powder, 4 g/L mixed nitrogen sources (ammonium sulfate: glutamic acid: tyrosine=2:1:1), 1.0 g/L MgSO₄, 0.40 g/L CaCl₂, 0.5% inoculum amount, 28 ℃, and pH 6.5. The PQQ production of the strain in shake flasks after 7 days of fermentation at the optimized conditions reached 61.48 mg/L, which increased by 3.3 times compared with that before optimization. Compared with CK, the PQQ-containing microbial agent increased the plant height, stem diameter, aboveground fresh weight, and belowground fresh weight of pepper by 35.05%, 8.22%, 14.41%, and 51.70%, respectively, demonstrating better plant growth-promoting effect than the PQQ solution. Moreover, the PQQ-containing microbial agent significantly improved the activities of antioxidant enzymes and the content of osmoregulatory substances (soluble sugar, soluble protein, and proline) in leaves, while increasing the soil nutrient content. The PQQ-containing microbial agent significantly changed the relative abundance of bacteria and fungi in the rhizosphere soil of pepper, increasing the relative abundance of Bacillus, Aspergillus, and Streptococcus by 1.99 times, 1.38 times, and 8.75 times, respectively, compared with CK. [Conclusion] A. calcoaceticus CDWB36 has the ability to produce PQQ. Optimizing the fermentation conditions can effectively enhance the PQQ production. The fermentation broth of CDWB36 significantly promotes pepper growth under drought stress, and PQQ is a key substance in the broth for promoting pepper growth. Therefore, the strain has broad application prospects in enhancing the stress resistance and promoting the growth of plants.

The first human Pegivirus (HPgV-1) and the second human Pegivirus (HPgV-2) are the only two human Pegiviruses that have been identified until now. They share some common features including similar viral genome structure and low pathogenicity, while they also represent unique biological characteristics. HPgV-1 is called "good virus" because of its ability to slow down disease progression and reduce disease severity when co-infecting with HIV and Ebola virus. In addition, HPgV-1 was recently found to be related with lymphoma and neurological diseases. Therefore, HPgV-1 might be a possible breakthrough point in the treatment of refractory diseases caused by HIV and other viruses. HPgV-2 was firstly discovered from the plasma of a hepatitis C virus (HCV)-infected patient in 2015 and was found to always co-infect with HCV but hardly infect healthy people. However, the underlying mechanism of HPgV-2 and HCV co-infection remains to be elucidated. Distinct from most of RNA viruses, HPgV-2 exhibits low genomic diversity with high sequence identity and low intra-host variation, which give the implication of HPgV-2 as an excellent model for studying the mechanisms of viral genome variations. In conclusion, the human Pegiviruses are worthy of sustaining attention and study.

Type 2 diabetes mellitus (T2DM) is a prevalent metabolic disease, yet its pathogenesis remains inconclusive. Recent studies have revealed a close relationship between the gut microbiota and T2DM, and specific gut microbiota structures and metabolic characteristics are associated with the onset and progression of T2DM. Exercise is an effective intervention for the prevention and management of T2DM, capable of reversing the dysbiosis induced by T2DM and regulating gut metabolites. However, the effects of exercise on the gut microbiota in T2DM patients still present many unresolved issues. Furthermore, the regulation of gut microbiota by exercise in T2DM patients is closely linked to multiple organs and can exert alleviation effects on T2DM via various gut-organ axis pathways. This paper reviews the characteristics of gut microbiota in T2DM and the effects of exercise on the gut microbiota in T2DM, with a particular focus on the mechanisms by which exercise regulates the gut microbiota to ameliorate T2DM via the gut-organ axis. This review aims to provide a reference for elucidating the relationship between exercise, gut microbiota, and T2DM.

[Objective] The basic leucine zipper (bZIP) factors are a group of large and conserved transcription factors in eukaryotes, and they are involved in the growth, development, and infection of pathogenic fungi in plants. This study aims to identify the bZIP transcription factors in the whole genome of Setosphaeria turcica and explore their functions during HT-toxin induction. [Methods] The members of the bZIP family were screened and identified from the genome database of Setosphaeria turcica, and their physicochemical properties, conserved domains, subcellular localization, cis-acting elements, phylogenetic relationship, and protein-protein interaction network were analyzed. The RNA-seq database was used to analyze the expression of bZIP family members during pathogen infection and HT-toxin induction. [Results] Fourteen bZIP family members (StbZIP1–14) were screened from the genome of Setosphaeria turcica, with significant differences in physical and chemical properties. These factors had the lengths of 226–613 aa, relative molecular weights of 25.24–66.30 kDa, isoelectric points of 4.66–10.36, and the subcellular localization in the nucleus. These factors carried 660 cis-acting elements involved in abiotic stress, hormone induction, cell cycle regulation, enhancers, and core promoters. The phylogenetic analysis with 11 other major pathogenic fungi in plants indicated that StbZIPs were clustered into 10 groups and had a clear co-linear relationship with AabZIPs of Alternaria alternata. The expression levels of StbZIP1, StbZIP5, StbZIP7, StbZIP10, and StbZIP11 were significantly correlated with HT-toxin induction, among which StbZIP5 had the highest expression level and demonstrated upregulated expression after 21 days and 28 days of HT-toxin induction. The protein-protein interaction network of StbZIPs predicted three StbZIPs interaction pathways centered on StbZIP5. [Conclusion] The members of the bZIP family of Setosphaeria turcica have significant physicochemical and structural differences, extensive genetic diversity, and significant functional differentiation, playing an important role in transcriptional regulation during HT-toxin induction.

[Objective] Streptococcus suis is a prevalent pathogen attacking pigs and a zoonotic agent. In 1998, an outbreak of S. suis infection in Jiangsu caused numerous pig deaths and 14 human deaths. Therefore, investigating S. suis infections in healthy pigs from slaughterhouses in Jiangsu is crucial for public health. [Methods] Tonsils were collected from healthy pigs in slaughterhouses of Jiangsu in 2023, and S. suis was isolated, identified, and serotyped. The pathogenicity of S. suis isolates to zebrafish and mouse models was examined. Furthermore, the antibiotic resistance characteristics and genes and the antimicrobial susceptibility of the isolates were identified and evaluated. [Results] The positive rate of S. suis in the samples collected from Kunshan in July 2023 was 50.85% (30/59). A total of 62 strains were isolated from the samples collected from Kunshan, and serotype 31 (12.90%, 8/62) had the highest isolation rate, followed by serotype 19 (11.29%, 7/62) and serotype NCL2 (8.06%, 5/62). In the samples collected from Danyang in July and November 2023, the positive rate of S. suis was 60.71% (34/56), and 77 strains were isolated. Serotype 16 had the highest isolation rate of 11.69% (9/77), followed by serotype 9 (10.39%, 8/77), serotype 21 (10.39%, 8/77), and serotype 31 (10.39%, 8/77). The isolates from both regions exhibited high resistance to lincosamides (98.56%, 137/139), macrolides (95.68%, 133/139), and tetracyclines (96.40%, 134/139). Furthermore, 97.84% (136/139) of strains were multi-drug resistant. All the strains were sensitive to cefotaxime and vancomycin. According to the sources and serotypes, we selected 42 representative strains (18 from Kunshan and 24 from Danyang) to perform zebrafish infection experiments. At a dose of 3×10⁶ CFU/fish, seven strains exhibited high pathogenicity to zebrafish, causing the mortality rates ≥80.00%. Three strains (serotypes 1, 3, and 23) causing mortality rates ≥80.00% in zebrafish and comparable to the virulent strain SC070731 were selected for mouse infection experiments. All the three strains led to the mortality rates ≥80.00% in mice. [Conclusion] The healthy pigs in Jiangsu have a high carrying rate of S. suis (55.65%, 64/115), and 97.84% (136/139) of the isolates are multi-drug resistant. Strains of serotypes 1, 3, and 23 exhibited strong pathogenicity.