Campanumoea lancifolia (Roxb.) Merr. is a new plant species with both medicinal and edible values, demonstrating broad prospects for development and utilization. However, as its cultivation area expands, root rot has become increasingly severe. In the fields with severe root rot, the losses can reach up to 40%, accounting for 75% to 90% of the losses caused by all diseases affecting C. lancifolia. Root rot directly leads to declines in fruit yield and quality, affecting the commercial value of the fruits and reducing farmers' incomes. Thus, it is urgent to address the root rot in C. lancifolia. [Objective] To isolate and identify the pathogens causing root rot in C. lancifolia and investigate the inhibitory effects of essential oils extracted from four aromatic medicinal plants on the growth of these pathogens. [Methods] Pathogens were isolated from C. lancifolia plants displaying typical root rot symptoms by the tissue culture method. The pathogens were identified based on morphological and molecular evidence and verified according to Koch's postulates. Essential oils were extracted from four aromatic medicinal plants by steam distillation. The Oxford cup method was employed to examine the inhibitory effects of the essential oils on the pathogens, and the 96-well plate method was used to determine the minimum inhibitory concentrations (MICs) of the essential oils. [Results] Four pathogenic strains were isolated and identified from the roots of diseased C. lancifolia plants. Re-inoculation of these pathogens induced root rot symptoms consistent with those observed in the field. The pathogens were identified as Fusarium oxysporum, Fusarium solani, Colletotrichum liriopes, and Stagonosporopsis pogostemonis. The essential oils exhibited strong inhibitory effects on these pathogens, with inhibition rates ranging from 32.94% to 95.29%. Additionally, the MICs of the four essential oils against the pathogens ranged from 0.031 mg/mL to 4.000 mg/mL. [Conclusion] This study demonstrates that F. oxysporum, F. solani, C. liriopes, and S. pogostemonis are pathogenic to C. lancifolia. This is the first report of F. solani, C. liriopes, and S. pogostemonis causing root rot in C. lancifolia. Furthermore, the essential oils extracted from the selected four aromatic plants exhibited strong inhibitory effects on the pathogens causing root rot in C. lancifolia, which coincides with the theory of aromatic plants dispelling pathogens in traditional Chinese medicine. The findings lay a scientific foundation for the development of botanical pesticides against root rot in C. lancifolia and the eco-friendly cultivation of this plant.

Adenosine diphosphate-ribosylation (ADPr) is a reversible post-translational modification that is catalyzed by adenosine diphosphate-ribosyltransferases (ARTs) and adenosine diphosphate- ribosylhydrolases (ARHs), and it widely occurs in eukaryotes and prokaryotes. ARHs are a class of key enzymes that can reverse ADPr modification of specific amino acid residues or specific sites/sequences of DNA and RNA. They can regulate the physiological metabolism, signal transduction, gene expression, and other key life processes in bacteria or hosts, playing an important role in the inter/intraspecific competition, stress responses, and pathogenicity of bacteria. This article reviews the classification, structural characteristics, and catalytic mechanisms of bacterial ARHs, aiming to enrich our understanding about the catalytic mechanisms and biological functions of ARHs in bacterial life.

Galactose is a ubiquitous monosaccharide in nature, serving not only as a primary carbon source for bioenergy metabolism but also as a precursor for various biological synthesis reactions. In eukaryotic cells, galactose or its derivatives can act as signaling molecules to participate in intercellular communication. Recent studies have revealed that galactose can modulate bacterial virulence by regulating intracellular signal transduction. Accordingly, galactose is considered an underappreciated environmental regulator in bacterial infection. However, the specific regulatory mechanisms remain incompletely elucidated. This review integrates the latest research findings to summarize the bacterial galactose metabolic pathway, the biological implications of galactose metabolism in bacterial virulence and interactions with hosts, and the key proteins (enzymes) in the galactose metabolism pathway as potential targets for developing novel vaccines. It offers new insights and reference for comprehending bacterial infection mechanisms and exploring innovative antibacterial strategies.

[Objective] To observe the effects of supplementing compound probiotics on the structure of gut microbiota, content of short-chain fatty acids (SCFAs), and levels of inflammatory cytokines in Chinese wrestlers. [Methods] Eighteen non-sports undergraduates from Shandong Sport University were recruited as a control group, while 30 Chinese wrestlers served as the experimental group. Both groups received oral compound probiotics for 8 weeks. Venous blood and stool samples were collected before and after the intervention. Enzyme-linked immunosorbent assay (ELISA) was used to measure inflammatory cytokines levels in plasma. The structural characteristics of gut microbiota were analyzed using 16S rRNA gene sequencing of the V3−V4 region, and gas chromatography-mass spectrometry (GC-MS) was employed to determine SCFAs content in stool samples. [Results] Prior to the intervention, the experimental group exhibited lower levels of interleukin-1 (IL-1), interleukin-6 (IL-6), and C reactive protein (CRP) (P < 0.001, P < 0.01, P < 0.01), and higher levels of interleukin-10 (IL-10) compared to the control group (P < 0.001). After 8 weeks of probiotic supplementation, plasma levels of IL-6 and CRP in the Chinese wrestlers further declined (P < 0.01, P < 0.05). Before the intervention, the abundance of Bifidobacterium adolescentis was higher in Chinese wrestlers than that in the control group (P < 0.01). Following 8 weeks of supplementation, Chinese wrestlers showed an increased abundance of Collinsella (P < 0.01), a decreased abundance of Faecalibacterium (P < 0.01), and reduced α-diversity in gut microbiota (P < 0.01). Prior to the intervention, there was no significant difference in SCFAs content between the two groups. After 8 weeks of intervention with compound probiotics, the content of acetic acid and butyric acid in the stool samples increased in both the control group (P < 0.01, P < 0.05) and the experimental group (P < 0.05). The correlation analysis results indicated a positive correlation between B. adolescentis abundance and plasma IL-10 level (r=0.233, P=0.037) and negative correlations of B. adolescentis and C. aerofaciens abundance with plasma IL-6 level (r=−0.499, P=0.000; r=−0.366, P=0.001) in Chinese wrestlers. Additionally, there was a positive correlation between C. aerofaciens abundance and the butyric acid content in stool samples of Chinese wrestlers (r=0.243, P=0.032). [Conclusion] The 8 weeks intervention with compound probiotics effectively reduced pro-inflammatory cytokine levels and increased anti-inflammatory cytokine levels in plasma. Furthermore, it enhanced the abundance of butyric acid-producing bacteria in the gut microbiota, promoting the production of SCFAs, and improving anti-inflammatory capacity.

[Objective] Based on the critical role of type Ⅰ signal peptidase in the secretion system, this study explores the interaction between signal peptidase and signal peptides to guide the optimization of aminopeptidase secretion expression in Bacillus amyloliquefaciens. [Methods] The endogenous signal peptidase and signal peptide of Bacillus amyloliquefaciens TCCC 19030 were examined using relative fluorescence intensity and enzyme activity for analysis, and molecular docking to study their interaction. [Results] The signal peptide YolC fused with aminopeptidase exhibited the highest extracellular enzyme activity, reaching 11 847.67 U/mL. Overexpression of the signal peptidase SipW increased aminopeptidase activity to 16 261 U/mL. Molecular docking results also showed that YolC had the lowest binding free energy with SipW, at −4.4 kcal/mol. [Conclusion] Optimization of signal peptides and overexpression of signal peptidase can effectively enhance the secretion of aminopeptidase. The binding energy between signal peptidase and signal peptide is a key factor influencing the secretion levels of the target protein.

[Objective] To explore the formation process of multi-species biofilms in paddy soils developed from different parent materials mediated by soil minerals, thus providing a scientific basis for revealing the interaction mechanisms between soil components and multi-species biofilms. [Methods] The multi-species biofilms were extracted from reddish clayey soil and acidic purple soil, and kaolinite and goethite were used as the mineral media. Modern biological microscopy, high-throughput sequencing, and infrared spectroscopy were employed to study the mineral-mediated formation process, structural changes, and bacterial community structure of the biofilm. [Results] Based on the high-throughput sequencing technology of 16S rRNA gene, the flora in the multi-species biofilms in the paddy soils developed from the two parent materials was dominated by Chloroflexi, Acidobacteria, Proteobacteria, Nitrospirae, and Desulfobacterota. Compared with the control without mineral addition, goethite and kaolinite significantly inhibited the formation of the multi-species biofilm dominated by Chloroflexi in the acidic purple soil, decreasing the biofilm biomass by 18.38% and 17.30%, respectively. In the reddish clayey soil dominated by Acidobacteria, goethite and kaolinite promoted the multi-species biofilm formation to varying degrees. Kaolinite demonstrated more significant promotion effect, increasing the biofilm thickness, the secretion of polysaccharides in the biofilm by 7.69%, and the biofilm biomass by 18.99%. [Conclusion] Kaolinite stimulated bacterial production of extracellular substances, promoted the multi-species biofilm formation in reddish clayey soil, and inhibited the multi-species biofilm formation in acidic purple soil. Goethite inhibited the multi-species biofilm formation in acidic purple soil. Compared with kaolinite, goethite is likely to cause cell inactivation. This study further revealed the interaction mechanism between soil components and multi-species biofilms, and the results provided a scientific theoretical basis for promoting the sustainable development of soil health.

Inhibitors including sugar degradation products (e.g., 5-hydroxymethylfurfural and furfural) and phenols (e.g., 4-hydroxybenzoic acid and vanillin) from lignin degradation are inevitably formed in the pretreatment process of lignocellulose raw materials, exerting a negative impact on the fermentation efficiency. [Objective] To improve the tolerance of yeast to inhibitors in cellulose hydrolysates and ensure the efficient production of industrial biomass ethanol. [Methods] The model strain W303-1A was domesticated with the inhibitor furfural and p-hydroxybenzoic acid alone or in combination. The growth curves and ethanol fermentation performance of the domesticated strain and the original strain were compared under different inhibitor concentrations. We then conducted high-throughput genome resequencing of both the domesticated and original strains to identify the mutations in genes related to the glucose metabolism and drug resistance, thereby analyzing the variation points related to inhibitor tolerance. [Results] In the medium containing 2.0 g/L furfural, the ethanol yield of F-2 was 19.40 g/L, which was 2 times higher than that of the original strain. In the medium containing 1.6 g/L furfural and p-hydroxybenzoic acid, the highest ethanol yield of B-2 was 20.22 g/L, 7.6 times that of the original strain. Then, high-throughput genome resequencing of the original and domesticated strains revealed several mutations in the genes encoding ethanol dehydrogenase, fructose-1, 6-diphosphate aldolase, and pyruvate dehydrogenase in the glucose metabolism pathway. The mutations of YAP1 (transcriptional activator involved in oxidative stress response and REDOX homeostasis), PDR5 (pleiotropic ABC transporter tolerant to multiple chemicals), and RPN4 (zinc finger protein) genes played an important role in the inhibitor tolerance of Saccharomyces cerevisiae. [Conclusion] The findings provide more targets for further optimization and construction of model strains.

Microbially enhanced coalbed methane production has become a research hotspot of coalbed methane production in recent years. Methanogens, the essential microorganisms in coalbed methane production, are usually strictly anaerobic and sensitive to oxygen. [Objective] To understand the changes in the methane production and composition of the anaerobic microbiome after exposure to oxygen, we conducted the enrichment culture of coalbed formation water collected from different regions along the east edge of Ordos Basin in China for air exposure experiments. Our findings are expected to provide scientific support for the future in-situ utilization of large-scale anaerobic fermentation products in coalbed methane production. [Methods] We used the enrichment cultures of coalbed formation water collected from Hancheng (HC), Baode (BD), and Linfen (LF) for air exposure for a series of time schedules within 24 h. The air-exposed enrichment cultures were re-inoculated and cultured. The methane production and community succession were analyzed to evaluate the microbiome tolerance to the aerobic condition. [Results] The microorganisms in all the three regions were still active after 24 hours of air exposure and showed the methane production comparable to that before air exposure. The dominant groups involved in the hydrolysis, acidification, and acetoxylation mainly included Firmicutes, Synergistetes, Proteobacteria, and Bacteroidetes. Methanogenic archaea were mainly Methanosarcina, Methanofollis, and Methanobacterium, belonging to Euryarchaeota. [Conclusion] After 24 hours of air exposure, the methane-producing capacity of the microbiome from the coalbed formation water was not affected and was comparable to that before air exposure. The microbiome did not showcase obvious succession, while the relative abundance of different groups changed accordingly. Our study can give scientific support for the in-situ industrial application of anaerobic enrichment culture from deep coalbed seams during coal degrading in methane production.

[Objective] This study isolated the dominant indole-3-acetic acid (IAA)-producing bacteria from the rhizosphere soil of Prunus sachalinensis, determined their plant growth-promoting properties, and clarified the growth-promoting effect by inoculation to the seedlings of the common rootstock Gisela 6, aiming to provide theoretical reference and practical approaches for exploring the biological potential of cherry, establish a benign root-microbial interaction relationship, and solve weak root development. [Methods] We used the beef extract peptone medium to isolate bacteria from the rhizosphere soil and selected various specific media to screen the bacteria and determine the IAA-producing, nitrogen-fixing, phosphorus-solubilizing, potassium-solubilizing, and chemotactic abilities of the bacteria. Then, we constructed a phylogenetic tree based on 16S rRNA gene sequences to identify the bacteria. Finally, potted cherry plants were used to explore the plant growth-promoting effects of the strains. [Results] Five IAA-producing strains were screened from the rhizosphere soil of P. sachalinensis, among which strain D46 had the highest IAA yield (53.10 mg/L). D5 was identified as Priestia sp. D27 and D46 were identified as Enterobacter sp. D43 and D79 were identified as Bacillus sp. All the five strains had the ability to fix nitrogen. D27, D46, and D79 had the ability to solubilize phosphorus, and D5 and D43 had the ability to solubilize potassium. Strains D27, D46, and D79 showed strong integrative chemotaxis to sugars, organic acids, and amino acids. Pot experiments showed that the inoculation of strains D27, D43, D46, and D79 significantly increased the root activity. After the inoculation of strain D27, the total root respiration rate increased by 51.40% compared with that in the control group (CK), and the root respiration rates of glycolysis (EMP), tricarboxylic acid cycle (TCA), and pentose phosphate pathway (PPP) also significantly increased. Strain D27 significantly improved the root architecture of cherry seedlings. After inoculation of strain D5, the net photosynthetic rate of leaves significantly increased by 58.82% compared with that in CK, and the inoculation of strain D27 demonstrated the best performance in improving the water use efficiency of leaves. Strains D27, D46, and D79 significantly increased the plant biomass. [Conclusion] There were IAA-producing bacteria in the rhizosphere of cherry, and the five IAA-producing strains isolated had other plant growth-promoting properties. Strains D27, D46, and D79 demonstrated comprehensive plant growth-promoting effects on cherry seedlings. In the future, we can explore the spectra of plants with growth promoted by the strains and the environmental tolerance of the strains, providing a theoretical basis for mining and enriching the strain resources of plant growth-promoting rhizobacteria.

Acinetobacter spp. are the common opportunistic pathogens worldwide and pose a threat to the health of humans and animals. As the resistance rate to carbapenems aggravates, tigecycline has become one of the last lines for the treatment of multidrug-resistant Acinetobacter spp. infection. The rapid dissemination of tigecycline resistance genes tet(X3), tet(X4), tet(X5), tet(X6), and other variants in recent years has seriously affected the clinical application of new tetracycline antibiotics such as tigecycline, eravacycline, and omadacycline, whereas there is a lack of review on the tet(X) genes in Acinetobacter spp. This article comprehensively expounds the mechanisms of action, epidemiological characteristics, transmission risks, and inhibitors of tet(X) genes in Acinetobacter spp. and evaluates the diversity of their variants, bacterial hosts, geographical distribution, and sampling sources, aiming to provide a theoretical basis for the prevention and control of tet(X)-positive Acinetobacter spp.