Since the formation of a committee under the guidance of R. E. Buchanan in 1936, microbiologists have developed and refined a nomenclatural code for bacteriology, the International Code of Nomenclature of Prokaryotes (ICNP). This code has greatly facilitated recent advances in taxonomy and related fields of microbiology. Technical developments in omics have led to a surge in genome-based discoveries of novel uncultured species, many of which play important roles in environmental and medical microbiology. Nevertheless, the ICNP only recognizes cultures as nomenclatural types, thereby preventing the names of the uncultured microorganisms from being validly published. To compensate for the ineffectiveness of the ICNP in creating permanent and stable names of uncultured taxa, the Code of Nomenclature of Prokaryotes Described from Sequence Data (SeqCode) was published in 2022. The SeqCode was formed with the intention of complementing and someday merging with the ICNP. However, as the two nomenclatural codes currently work independently, the consequences of the concurrence of both codes on the scientific community are still not clear. Here, we introduce the histories and principles of the ICNP and SeqCode, summarize their advantages and limitations, and call for scholars to both respect and utilize the two nomenclatural codes of prokaryotes, aiming to facilitate the establishment of a more reasonable and beneficial naming system.

Botulinum neurotoxins (BoNTs), a group of the most toxic proteins, can cause muscle paralysis and even lead to death in severe cases. BoNTs can be classified into 7 serotypes (BoNT/A−BoNT/G) and further classified into more than 40 subtypes according to the differences in amino acid sequences. BoNTs consist of three basic domains: the C-terminal receptor-binding domain of the heavy chain, the N-terminal translocation domain, and the light-chain catalytic domain. On the surface of motor neurons, the receptor-binding domain binds first to polysialoganglioside and subsequently to synaptic vesicle protein 2 or synaptotagmin to form a two-receptor complex. The functioning of each serotype relies on the binding of the receptor-binding domain to the corresponding receptor. BoNTs have always been a research hotspot in terms of the structure, function, and effect on the host. The role of the receptor-binding domain in promoting the specific binding of BoNTs to motor neurons has become a new research direction. This review summarizes the structural changes of the receptor-binding domains and the differences in binding sites during the binding of different serotypes of BoNTs to receptors. By analyzing the sequences and structural characteristics of the receptor-binding domains of different serotypes and subtypes, we can fully understand the sequence differences and functions of the receptor-binding domain and give insights into the treatment of BoNTs.

Bacterial cellulose, a natural biopolymer with higher purity and better mechanical properties than plant cellulose, is expected to be widely used as a new green polymer material. A variety of bacteria have now been proven to have the ability to produce cellulose, in which bacterial cellulose synthase plays a crucial role. Therefore, understanding the catalysis mechanism of bacterial cellulose synthase is a key to the mass production and broad utilization of bacterial cellulose. This paper reviews the basic properties of bacterial cellulose synthase, including the screening of strains, the enhancement of yield, and the cellular localization of the synthase, aiming to promote the research on the catalysis mechanism of cellulose synthase. Further, based on the mechanism of cellulose synthase, this paper detail the influencing factors ofin vitro synthesis and review the research progress in the roles of each subunit of this synthesis method. We explore the catalysis mechanism of bacterial cellulose synthase, point out the problems in the current research, and envision the future research directions in this field, with a view to providing a theoretical basis for the large-scale application of bacterial cellulose by deciphering the synthesis mechanism.

Urothelial carcinoma of bladder (UCB) is a common malignant tumor of the urinary system and a common pathological type of bladder cancer (BC). With high morbidity, high mortality, and easy recurrence, UCB poses a serious threat to human health. The occurrence of UCB may be associated with smoking and exposure to toxic chemicals. With the deepening of research, researchers have discovered unique microbiota related to the occurrence and development of UCB in the bladder. This review focuses on the involvement of microbiota in the occurrence and development of UCB through urinary tract infection (UTI), affecting epithelial-mesenchymal transition (EMT), and up-regulating the expression of programmed cell death 1 ligand 1 (PD-L1). At the same time, this paper introduces the microbiota characteristics of healthy people and UCB patients as well as the prevention and treatment of UCB. By reviewing the relationship between microbiota and UCB, this paper provides new ideas for further clarifying the promoting effect of microbiota on UCB and developing drugs for treating UCB.

Food allergy (FA) with growing incidence has emerged as one of the public health problems around the world as it seriously affects the life quality of children. Recent studies have discovered that there are significant differences in the composition of gut microbiota between the children with FA and healthy children. In-depth studies have reported that gut microbiota can help to maintain immune balance by regulating immune cells such as dendritic cells, helper T cells, regulatory T cells, mastocytes, and granulocytes. In addition, gut microbiota can enhance the intestinal barrier function to inhibit FA in a variety of ways. On the basis of research results from animal experiments, probiotics and prebiotics have been used in the treatment of FA in children, whereas the effect is not ideal. As FA occurs in a growing number of children in the world, this article reviews some mechanisms of gut microbiota in influencing FA and summarizes the application of probiotics and prebiotics in the treatment and prevention of FA in children in recent years. Furthermore, this article proposes new ideas for deciphering the mechanism of gut microbiota in regulating FA and applying probiotics and probiotic metabolites in the treatment and prevention of FA in children, which is of great significance for promoting the research on the treatment of FA in children.

Bacterial infection has become one of the major problems threatening public health, and the abuse of antibiotics has accelerated the development of bacterial resistance. Antimicrobial peptides have attracted extensive attention due to their broad-spectrum antibacterial activity, rapid bactericidal effect, low toxicity, and low risk of drug resistance. However, the natural structures of antimicrobial peptides indicate some limitations, such as easy degradation, instability, low permeability, and high costs, in their application. How to improve antimicrobial peptides is still a problem to be solved. From the sources and structural characteristics of antimicrobial peptides, we analyzed the spatial structures related to the antibacterial activity and corresponding antibacterial mechanisms. In addition, we summarize the existing improvement strategies of antimicrobial peptides to lay a foundation for seeking new improvement schemes. This review provides new ideas and directions for the modification and clinical application of antimicrobial peptides in the future.

[Objective] To clarify the promotion effects of different organic compounds on the formation of magnetosomes inAcidithiobacillus ferrooxidans BYM, so as to provide a new idea for safely and effectively improving the magnetosome yield. [Methods] Single-factor experiments were conducted to measure the effects of ten organic compounds on the ferrous oxidation ofA.ferrooxidans BYM, and the organic compounds promoting the synthesis of magnetosomes were further screened by a 4 L fermentation system. The classical kinetic models (Logistic, Luedeking-Piret, and substrate consumption kinetic equations) were employed to build the kinetic models for the growth, magnetosome synthesis, and ferrous consumption ofA.ferrooxidans BYM by batch fermentation experiments. [Results] The maximum magnetosome yield (2.00×10⁻³ g/L) was achieved with the addition of 10 mmol/L gluconic acid, in the presence of which the bacterial cells were oval and had a smooth surface. With the addition of gluconic acid, the fermentation kinetics ofA.ferrooxidans BYM was in accordance with Logistic, Luedeking-Piret, and substrate consumption kinetic equations. [Conclusion] The addition of 10 mmol/L gluconic acid increases the magnetosome yield ofA.ferrooxidans BYM by eight times. Gluconic acid changes the cell morphology and surface ofA.ferrooxidans BYM. The kinetics models of cell growth, product formation, and substrate consumption can illustrate the batch fermentation ofA.ferrooxidans BYM in the presence of gluconic acid.

[Objective] The biosafety of silver nanoparticles (AgNPs) has been a subject of concern due to the narrow therapeutic window. Expanding the therapeutic window could facilitate the application of AgNPs in the treatment of multi-drug resistant bacterial infections in humans and animals. This study aimed to enhance the biosafety of AgNPs by modifying their surface with alpha-ketoglutaric acid (AKG), a crucial component of the tricarboxylic acid cycle. [Methods] Silver ion was reduced to AgNPs by rutin at room temperature, and then AgNPs were stabilized with 1 mmol/L polyvinylpyrrolidone (PVP) solution to generate PVP-AgNPs. AKG (10 mmol/L) was added to generate PVP-AgNPs@AKG. The prepared AgNPs were characterized by a full-wavelength spectrophotometer, a particle size analyzer, and a transmission electron microscope. The antibacterial activities of PVP-AgNPs and PVP-AgNPs@AKG were evaluated based on minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), time-kill curve, and post-antibiotic effect. The cytotoxicity of the prepared AgNPs to human cervical epithelial cells (HCerEpic) was examined by the MTT assay and flow cytometry. Furthermore, the effects of the prepared AgNPs on the energy metabolism, oxidative stress, and expression of genes involved in anaerobic respiration ofEscherichia coli BW25113 were studied. [Results] The MIC and MBC of PVP-AgNPs@AKG against Gram-positive and Gram-negative bacteria were 50% or above 50% lower than those of PVP-AgNPs. PVP-AgNPs@AKG and PVP-AgNPs showed no significant difference in the cytotoxicity to HCerEpic cells. Compared with PVP-AgNPs, PVP-AgNPs@AKG at the MIC showed significantly enhanced inhibitory effect on the α-ketoglutarate dehydrogenase inEscherichia coli, increased accumulation of AKG, lowered ATP level, and elevated reactive oxygen species level. Moreover, PVP-AgNPs@AKG significantly up-regulated the expression ofsoxS and down-regulated the expression of genes involved in anaerobic respiration, such asarcA,fnr, andfdnH. [Conclusion] The findings suggested that PVP-AgNPs@AKG disrupted the energy metabolism by targeting α-ketoglutarate dehydrogenase, rending bacteria more vulnerable to oxidative damage. Modifying with AKG would be a potential method to expand the therapeutic window of AgNPs.

[Objective] Environmental fungi emerge as the principal agents causing microbial deterioration of museum collections. The varying materials and origins of collections and the different storeroom environments in a museum contribute to high diversity of environmental fungi. Additionally, the air conditioning system within a museum may instigate fungal dispersion among storerooms. Recognizing the compositional differences and seasonal variations of fungal communities in the air across varied storerooms underpins the early warning and prevention against microbial hazards in museum settings. [Methods] Sampling was carried out every two months by the impacting method in the iron and silk storerooms of a museum for one year. Fungal species and community composition were examined by ITS rDNA sequencing. [Results] The amplicon sequencing yielded a broad spectrum of fungal data, encompassing five phyla, 20 classes, and 184 families, over half of which displayed notable seasonal changes. Distinct and comparatively consistent fundamental fungal populations existed in both iron and silk storerooms, exhibiting minimal seasonal variations. However, during summer when it was humid, substantial proliferation of the fungi capable of degrading proteinaceous and cellulosic materials was observed in both storerooms, which presented a latent hazard to the collections. Furthermore, it was noted that certain fungi produced acidic by-products during growth, which could compromise the integrity of the collections. [Conclusion] This investigation provides groundwork for the mitigation and management of environmentally derived fungal threats in museum contexts, underscoring importance for the preventive conservation of museum collections.

[Objective] A genetically engineered virus strainrGS15-∆2 with deletion of the residues at the positions 519–565 and 628–747 of the non-structural protein 2 (NSP2) had been rescued based on the PRRSV/GSWW/2015 infectious clone. This study aims to construct and rescue an engineered virus strain with the deletion of three sites in NSP2 based onrGS15-∆2. [Methods] Based on the infectious clones ofrGS15-∆2, two recombinant plasmids with the deletion of three sites were constructed by fusion PCR. Specifically, the dominant epitope at the amino acid site 323–364 or 372–433 of NSP2 was further deleted on the basis ofrGS15-∆2. The recombinant plasmids were linearized and mixed with liposome, which were transfected into Marc-145 cells for virus rescue. The growth characteristics of the engineered virus strains were analyzed by electron microscopy, immunofluorescence assay (IFA), virus titer determination, and growth curve establishment. [Results] The engineered virus strainsrGS15-∆3-1 andrGS15-∆3-2 were rescued successfully. Virions with the diameter from 50 nm to 80 nm can be observed under an electron microscope. The results of IFA confirmed the expression of PRRSV N protein by the rescued virus strains and the parent strain GS15. Furthermore, the rescued viruses were cultured with Marc-145 cells for 40 passages, and the deletion regions were confirmed to be stable by RT-PCR and sequencing. The titers ofrGS15-∆3-1 andrGS15-∆3-2 were 2.00×10^6.0 TCID₅₀/mL and 2.25×10^5.8 TCID₅₀/mL, respectively, which had differences from that of the parent strain (P < 0.05). The growth curves showed that the rescued viruses had lower replication levels than the parent strain, and they reached the peak titers 24 h later than the parent strain. [Conclusion] We characterized the growth of the viruses with the deletion of multiple sites in NSP2 of PRRSV. The findings laid a foundation for the development of novel PRRSV-labeled vaccines and provided a new strategy for the prevention and control of porcine reproductive and respiratory syndrome.