Insects have a mutually dependent symbiotic relationship with their gut microbiota, which plays an important role in the insect metabolism, immunity, development, and pesticide resistance. Gut microbiota is influenced by factors such as diet, sex, and rearing environment. Currently, little is known about the gut microbiota differences between males and females of the phytophagous insect Dolycoris baccarum. [Objective] To study the effects of sex on the composition and abundance of gut microbiota in D. baccarum, explore sex-related microorganisms, and provide a basis for utilizing different sex-associated strains in the biocontrol of D. baccarum. [Methods] The PacBio platform was used for third-generation 16S rRNA gene amplicon sequencing and the bioinformatics analysis was performed to reveal the diversity and composition of gut microbiota in male and female D. baccarum. The bacterial isolation and culture method was employed to obtain gut microbiota strains from D. baccarum, which were then identified by morphological analysis and 16S rRNA gene sequencing. [Results] The gut microbiota of D. baccarum was diverse, including a total of 165 genera belonging to 109 families, 60 orders, 29 classes of 14 phyla. The gut microbiota was analyzed at six taxonomic levels (phylum, class, order, family, genus, and species). Only the phylum Deinococcota and the class Deinococci were specific to males, while the phyla Chloroflexi, Desulfobacterota, and Cyanobacteria, the class Cyanobacteriia, the genus Lacticaseibacillus, and the species Glutamicibactercreatinolyticus, Acinetobacter, and Lacticaseibacillus paracasei were specific to females. The relative abundance of Serratia marcescens was significantly higher in males than in females. In the guts of females and males, the relative abundance of Gammaproteobacteria, Enterobacterales, Yersiniaceae, Serratia, and S. marcescens was 51.223% and 95.512%, 49.784% and 95.492%, 2.385% and 10.377%, 2.383% and 10.372%, and 2.310% and 10.375%, respectively. All 28 strains isolated in vitro and identified based on morphological characteristics and 16S rRNA sequences belonged to Serratia. [Conclusion] There are significant differences in the gut microbiota composition between male and female D. baccarum. The diversity of gut microbiota in male adults of D. baccarum is significantly higher than that in female adults. All strains isolated belong to Serratia. This study provides theoretical support for investigating the potential functions of gut microbiota in male and female D. baccarum as well as for the biocontrol of D. baccarum.

[Objective] To analyze the metabolic substrates required for the sclerotial formation of Rhizoctonia solani and understand the influence of nutritional elements and environmental factors on this process. [Methods] Biolog phenotypic microarray was used to study the effects of 663 nutritional substances, 96 osmotic environments, and 96 pH environments on the sclerotial formation of R. solani. [Results] Among the tested nutritional substances and environmental conditions, 19/95 carbon sources, 21/95 nitrogen sources, 16/94 phosphorus and sulfur sources, 69/94 nutritional supplements, 61/282 peptide nitrogen sources, 28/96 osmotic environments, and 40/96 pH environments induced the sclerotial formation of R. solani. Notably, N-acetyl-d-glucosamine, uridine 3′-monophosphate, phosphoryl choline, and five dipeptides (Arg-Trp, Met-Arg, Pro-Phe, Val-Tyr, and Val-Met), as well as three environmental conditions of 10 mmol/L and 20 mmol/L ammonium sulfate at pH 8.0, and pH 4.5+l-proline, significantly induced the sclerotial formation of R. solani. R. solani formed sclerotia in the environments with a broad range of pH 4.0-10.0. The KEGG analysis indicated that the substances inducing sclerotial formation were primarily involved in metabolic pathways, ABC transporters, secondary metabolite biosynthesis, and d-amino acid metabolism. [Conclusion] Nutrient limitation and environmental stress are key factors inducing the sclerotial formation of R. solani. Under nutrient-restricted conditions, the suitable substances for inducing sclerotial formation include five carbon sources (d-sorbitol, d-xylose, N-acetyl-d-galactosamine, d-arabinose, and d-melezitose), three nitrogen sources (N-acetyl-d-glucosamine, adenosine, and thymidine), two phosphorus sources (uridine 3′-monophosphate and phosphoryl choline), one nutritional supplement (Tween-80), and five peptide nitrogen sources (Arg-Trp, Met-Arg, Pro-Phe, Val-Tyr, and Val-Met). The suitable osmotic environments were 10 mmol/L and 20 mmol/L ammonium sulfate at pH 8.0, and the suitable pH environments were pH 4.0-4.5 and pH 9.5-10.0. These findings provide a foundation for understanding the sclerotial formation mechanism of R. solani.

Algae and bacteria are both the oldest forms of life on our planet, and billions of years of natural evolution have driven the algae and their microbiomes to evolve into interactive phycobionts. Through complex, flexible, intelligent, and multi-interface interactions between algae and bacteria, the functions of both sides of the phycobionts are exquisitely regulated. The creation, innovation, and development of the phycobiont theory shows vital scientific value for revealing the mystery of the origin and evolution of the life on Earth, and this theory is also being transformed into diverse practical applications in significant fields for sustainable development. After centuries of incubation, knowledge accumulation and development, currently, it is the right time to promote Phycosphere Microbiology to develop into an emerging interdiscipline. In this review, we comprehensively discussed the core concepts of Phycosphere Microbiology, sorted out its vital relationships with environment protection, human health maintenance, resource utilization, and green-oriented transition of energy, then reviewed its development history, and summarized the main research achievements during three development periods. Finally, we also proposed and discussed the future development trends and potential research directions for this emerging interdiscipline.

Bacillus subtilis is a generally recognized as safe (GRAS) probiotic and an excellent industrial chassis strain. It possesses advantages such as strong heterologous protein secretion capability, robust growth with low-quality carbon sources, and negligible codon bias. Since 2016, clustered regularly interspaced short palindromic repeats (CRISPR)-based gene editing has been successfully applied to B. subtilis, enabling precise genetic modifications, including point mutations, gene knockout, foreign gene insertion, gene expression regulation, and base editing. These advancements have significantly promoted the development of B. subtilis as an efficient microbial cell factory and have shown broad application potential in agriculture, pharmaceuticals, food production, and synthetic biology. This paper systematically review the development of the CRISPR system in B. subtilis and summarize its application in the efficient production of various products. The aim is to provide insights into the targeted optimization of metabolic pathways in B. subtilisvia the CRISPR system to achieve efficient and stable industrial production of target products, as well as to offer references for the further development and application of novel gene editing systems.

Activation induced cytidine deaminase (AID) and apolipoprotein B mRNA editing enzyme catalytic peptide (APOBEC) constitute a conserved family of cytidine deaminase enzymes. The family members have different functions in the body, and they play an important role in the immune defense of the host. AID plays a role mainly in the adaptive immune systems of vertebrates, mediating class switch recombination, antibody affinity maturation, and antibody diversity generation. APOBEC1 capable of catalyzing cytosine deamination, mediating RNA editing for cellular regulation, and resisting retroviral infection is involved in tumorigenesis and cancer development. APOBEC2, most abundant in cardiac and skeletal muscle, is associated with muscle fiber type switch, loss of weight, muscle development, and myopathy. Moreover, it may have potential indirect effects in controlling gene expression. APOBEC3s play key roles in both innate and adaptive immune responses. They are involved in the inhibition of retrotransposon functioning and viral infection, DNA degradation, RNA editing, and cell cycle regulation. The APOBEC4 gene is conserved in various animal species, with the active center sequence different from those of other APOBEC proteins. It is widely recognized that APOBEC4 is a uridine-editing enzyme, which has antiviral activity. The research is limited regarding the animal-derived APOBEC family members. This review describes the structural characteristics and biological functions of APOBEC family members, providing reference for research on the roles of animal-derived APOBEC family members in the immune responses and disease control. In addition, this review provides new ideas for the development of antivirals by enhancing the activities of APOBEC family members.

Organic contamination of crops poses a threat to the safety of food products and human health, and it is urgently needed to be solved. Endophytic bacteria are indispensable in microecosystems. In recent years, researchers have screened and isolated endophytic bacteria with the function of degrading pollutants from the environment. These bacteria have been used to regulate the metabolic processes of organic pollutants in crops, which achieve the efficient reducing of toxic organic pollutants in crops. This paper reviews the research progress in the reduction of toxic organic pollutant accumulation in crops by functional endophytic bacteria, focusing on the degradation genes, products, and pathways of toxic organic pollutants in crops after the colonization of functional endophytic bacteria. Furthermore, it discusses the factors affecting the degradation efficiency of functional endophytic bacteria and emphasizes the importance of these bacteria in reducing organic pollutants in crops. This review provides ideas and a basis for the further utilization of endophytic bacteria to control the risk of organic contamination in crops.

N-Heterocyclic carbine-silver (Ag-NHC) complexes possessing excellent stability, water solubility, and bactericidal activity are antimicrobial candidates with great potential. [Objective] To study the inhibitory activity and mechanism of a novel Ag-NHC complex 1,3-dibenzyl-4,5-diphenylimidazol-2-ylidene silver (I) acetate (SBC3), synthesized by Matthias Tacke’s team against Escherichia coli. [Methods] Visible spectrophotometry was employed to examine the antimicrobial activity of SBC3. Transmission microscopy was employed to observe the morphological changes of DHB4 cells post SBC3 treatment. Flow cytometry was performed to detect the effect of SBC3 on the intracellular reactive oxygen species (ROS) content. The 5,5′- dithiobis-(2-nitrobenzoic acid) (DTNB) assay was used to determine the intracellular thioredoxin (Trx) and thioredoxin reductase (TrxR) activities and the content of glutathione (GSH) post SBC3 treatment. Dithiothreitol (DTT), the ROS scavenger, was added to rescue DHB4 from ROS. SBC3-resistant strains (SRSs) were obtained by successive passaging in the laboratory. The obtained strains showed the minimal inhibitory concentrations (MICs) against SBC3 being 24, 32, and 56 μg/mL, respectively, which were 3, 4, and 7 folds of the MIC of WT. The three strains were named SRS3, SRS4, and SRS7 and then used to retest the above indicators. Western blotting was performed to determine the expression levels of Trx1 and S-glutathionylated proteins (S-PSSG) post SBC3 treatment. [Results] The MIC values of SBC3 against tested pathogens were 8.0–30.0 μg/mL. The DHB4 cells treated with SBC3 underwent swelling, which was accompanied by contents leakage. SBC3 significantly inhibited the Trx and TrxR activities, reduced the GSH content, and elevated the ROS level in DHB4. SBC3 treatment decreased the Trx and TrxR activities, reduced the GSH content, and down-regulated the expression of S-PSSG in SRS3, SRS4, and SRS7. However, all the above indicators were increased to different extent compared with those in DHB4. [Conclusion] SBC3 can target the thiol-dependent redox system (TDRS) of E. coli to exert antibacterial effects. This study provides a new idea for the design of SBC3 as a novel antimicrobial agent.

Tuberculosis is an ancient zoonotic disease that poses a serious threat to the health of humans and animals worldwide. Mycobacteriumtuberculosis (Mtb) is the primary causative agent of tuberculosis. As a bridge between innate and adaptive immunity, dendritic cells (DCs) play a pivotal role in controlling Mtb infection by utilizing their potent antigen-presenting capacity to activate the adaptive immune response of the host and thus resist further infection. In recent years, more and more studies have shown that Mtb can evade host immune defenses by regulating DC differentiation and maturation, interfering with phagocytosis and autophagy, and inhibiting the expression of antigen presentation-related molecules, thus causing persistent infection. This review summarizes the current research on the molecular mechanisms of Mtb in regulating DC antigen presentation, aiming to provide insights for further study of Mtb-DC interaction mechanism and development of prevention and control strategies for tuberculosis.

The bacterial stringent response refers to the adaptive reaction that bacteria exhibit when faced with adverse environmental conditions, altering their metabolism and reducing the growth rate to enhance survival and adaptability. The rapid accumulation of guanosine tetraphosphate (ppGpp) and guanosine pentaphosphate (pppGpp), collectively referred to as (p)ppGpp in this article, mediates the stringent response, playing a crucial role in microbial adaptation to environmental changes. The levels of (p)ppGpp within bacteria are regulated by RelA/SpoT homologue (RSH) proteins, which include small alarmone synthetases (SASs), small alarmone hydrolases (SAHs), and bifunctional proteins such as Rel. Furthermore, recent studies have identified a new bacterial alarmone, adenosine tetraphosphate (ppApp) and adenosine pentaphosphate (pppApp), collectively referred to as (p)ppApp, which is involved in the regulation of various biological processes in bacteria. The enzymes involved in (p)ppGpp metabolism vary among different bacterial species. This study systematically classifies and reviews the structural and biochemical characteristics of the known RSH proteins and summarizes their biochemical functions, aiming to promote further exploration and development in this field.

[Objective] To express the recombinant nonstructural protein NSP1 of the porcine reproductive and respiratory syndrome virus (PRRSV) strain NADC 30, evaluate its immune effect in mice, and explore the potential value of the nonstructural proteins of PRRSV as vaccine antigens. [Methods] The prokaryotic expression system was used to express NSP1 of NADC30. After purification, the expression and antibody reactivity of NSP1 in vitro were identified by Western blotting. After mice were immunized with NSP1, the levels of cellular and humoral immunity induced by NSP1 were measured. The level of neutralizing antibody induced by NSP1 was evaluated by the virus neutralization assay. [Results] The target gene of NSP1 was connected to the Escherichia coli pET-28a vector for prokaryotic expression. Western blotting identified that the recombinant protein NSP1 was correctly expressed and had antibody reactivity. After mice were immunized with the confirmed recombinant protein NSP1, the levels of interferon (IFN)-γ and tumor necrosis factor (TNF)-α in the spleen lymphocytes of mice were elevated, and cellular immunity was stimulated. At the same time, the recombinant protein NSP1 significantly improved the proliferation of spleen lymphocytes in mice. ELISA results suggested that the level of specific antibodies in the serum rose after immunization. Further analysis of the specific antibody subtypes (IgG2a and IgG1) produced showed that the type of immunity stimulated by recombinant NSP1 was biased to Th2 humoral immunity. In addition, the virus neutralization assay showed that the recombinant protein NSP1 had a good virus neutralization ability, with the neutralization titer of 1:37 on day 28 and 1:31 on day 42, which were significantly higher than those of the PBS control group and had no difference from those of the commercial vaccine group. [Conclusion] The recombinant nonstructural protein NSP1 of PRRSV can stimulate cellular and humoral immunity in mice and has a good virus neutralization ability, which provides a new idea for the development of next-generation PRRSV vaccines.