Electromagnetic radiation is a widespread physical phenomenon and exerts complex and profound effects on microorganisms. Understanding the state and function changes of microorganisms exposed to radiation is helpful to reveal the environmental response mechanisms of microorganisms and discover potential risk factors that threaten human health. By reviewing the relevant articles, we first discuss the damage of different types of electromagnetic radiation, including microwave, infrared, ultraviolet, X-rays, and γ-rays, to microorganisms. Furthermore, we elaborate on the molecular mechanisms by which electromagnetic radiation damages microorganisms from multi-omics. Finally, we reveal the potential relationship between the changes in the microbiome composition and the development of diseases in humans exposed to electromagnetic radiation.

Plastic pollution is an environmental problem that has aroused global concern, and plastics degradation by insect gut microbiota is a new initiative to solve this problem. Despite the important role of insect gut microbiota in the degradation of plastics, little is known about the composition and dynamics of insect gut microbiota. [Objective] To study the effects of feeding plastics on the physiological indices and the composition and dynamics of gut microbiota in the larvae of four insect species. [Methods] Polystyrene (PS), polyethylene (PE), and wheat bran (control) were used as the sole carbon source respectively to feed the larvae of Zophobas atratus Fab., Tenebrio molitor L., Tenebrio obscurus F., and Galleria mellonella L. The dynamics of gut microbiota in the larvae of the four insect species were investigated by fluorescence in situ hybridization, and the correlations between the physiological indices and gut microbiota were analyzed. [Results] All four insect species fed with PS and PE had significantly lower body weight gain and body length increase than those in the control. The survival rates of Z. atratus and T. molitor larvae fed with PS were 25.33% and 11.75%, respectively, higher than those fed with PE. The dominant microbial taxa of the gut microbiota in the four insect species were Firmicutes (relative abundance of 16.98%–54.93%), Betaproteobacteria (5.91%–39.34%), Gammaproteobacteria (4.62%–30.86%) of Proteobacteria, and Euryarchaeota (9.99%–58.05%). [Conclusion] In addition to Firmicutes and Proteobacteria, archaea were also dominant in the gut microbiota in the larvae of the four species fed with PE and PS. The relative abundance of the main microbial taxa in the insect gut varied dynamically over time and was influenced by the types of plastics as well as the insect species. The body weights and body lengths of Z. atratus and T. molitor were correlated with their gut microbiota.

[Objective] To investigate the enzymatic properties and straw-degrading effect of a recombinant xylanase rRuXyn024. [Methods] We cloned RuXyn024 from the rumen of beef cattle and used bioinformatics tools for detailed sequence analysis. The expression vector pET-RuXyn024 was constructed and transformed into Escherichia coli BL21(DE3) for heterologous expression of RuXyn024. Furthermore, the enzymatic properties and straw-degrading effect of rRuXyn024 were examined. [Results] RuXyn024 was composed of 358 amino acid residues and had a molecular weight of approximately 40 kDa, belonging to the GH 10 family. The optimal pH and temperature of rRuXyn024 were pH 7.0 and 40 ℃, respectively. The relative activity of RuXyn024 at pH 6.0−9.0 and 30−70 ℃ remained above 60% and 70%, respectively. With xylan from wheat straw as the substrate, rRuXyn024 showcased the K_m and V_max of 18.8 g/L and 82.6 µg/min, respectively. The activity of rRuXyn024 was inhibited by Mg²⁺, Zn²⁺, Cu²⁺, Ni²⁺, EDTA, and SDS at 1 mmol/L and 5 mmol/L, as well as 5 mmol/L Ca²⁺ and β-mercaptoethanol. Cu²⁺ and β-mercaptoethanol at 5 mmol/L nearly inactivated the enzyme. Mn²⁺ at 1 mmol/L and 5 mmol/L increased the activity of rRuXyn024 by 46.9% and 35.8%, respectively. The degradation of xylan from wheat straw by rRuXyn024 produced oligosaccharides, including xylotriose and xylobiose. rRuXyn024 could degrade maize straw, rice straw, soybean straw, and rapeseed straw, with the strongest degrading effect on maize straw. [Conclusion] rRuXyn024 exhibits tolerance to broad scopes of pH and temperature and significant potential for improving the utilization of straw by ruminants.

[Objective] Certain strains of Ligilactobacillus salivarius possess excellent probiotic properties and strong potential for application. This study characterized strain ATCC 11741 in terms of the growth characteristics, stress tolerance, and adhesion capacity, aiming to provide a theoretical basis for the utilization of L. salivarius. [Methods] L. salivarius ATCC 11741's accuracy was verified through morphological observations and 16S rRNA gene sequencing; its growth characteristics were investigated by tracking growth and acid production curves; additionally, a range of tolerance tests, including those with acid, alkali, bile salts, hyperosmolarity and temperature, were conducted to evaluate its tolerance; lastly, self-aggregation and hydrophobicity experiments were used to indirectly determine its adhesion. [Results] The growth curve of L. salivarius ATCC 11741 was formed like a "S". The strain reached its highest acid production between 2–7 h, stabilizing at pH 4.3 after 14 h. After being cultured in the MRS medium at pH 2.0 for 4 h, the strain had a survival rate of 50.48% and grew well in the pH 4.0–11.0 range. Following 2 h of incubation in the MRS medium with 0.10% bile salt, the strain's survival rate was 94.440 0%. In the MRS medium with 6% NaCl, the strain continued to proliferate. The growth of strain ATCC 11741 was significantly affected by temperature, being promoted at 30–42 ℃ and inhibited at 20 ℃ and 50 ℃. At the 5 h mark, the strain's hydrophobicity (measured by the hydrocarbon compound adhesion method) was 44.5% and its self-aggregation rate was 41.4%. [Conclusion] L. salivarius ATCC 11741 is a strain with fast growth, strong tolerance to acids, alkali, and salts, moderate tolerance to bile salt, a wide range of suitable temperatures, and strong adhesion capacity.

Giant pandas, despite having the digestive systems of carnivores, have evolved to thrive on a bamboo-based vegetarian diet, which results in a unique gut microbiota. With the advancement of science and technology, our understanding of the gut microbiota of giant pandas has evolved from simple strain isolation to exploring the intricate relationship between the microbiota and metabolic functions of the hosts as well as predicting the functions of the microbiota. In this review, we summarize the characteristics of the bacterial and fungal communities in giant pandas, examining the effects of the factors such as age, diet, habitat, and health conditions on gut microbiota. Furthermore, we discuss how these factors influence the metabolism of the gut microbiota. This review is expected to provide a theoretical basis for the future research on the intricate structure and functions of gut microbiota in giant pandas. The knowledge can pave the way for innovating the measures to enhance and stabilize the gut microecological environment, ultimately contributing to the conservation of giant pandas.

[Objective] This study aims to validate the functions of two ferritin-encoding genes: bacterioferritin (Bfr)-encoding gene (atu2771) and DNA-binding protein from starved cells (Dps)-encoding gene (atu2477), in Agrobacterium fabrum, to determine the open reading frame (ORF) of the Bfr-encoding gene, to investigate the effects of terminal fusion, heme group, and key residues on the function and self-assembly of A. fabrum Bfr, and to explore the potential applications of the two ferritin nano-cages. [Methods] We re-introduced the two ferritin-encoding genes into the ferritin-deficient mutants of A. fabrum respectively via plasmids to verify if the re-introduction could complement the ferritins of the ferritin-deficient mutants and thus validate the functions of the two genes. Native PAGE was employed to separate the ferritins in the crude extract of A. fabrum and potassium ferrocyanide (an iron-specific staining reagent) was used to stain the ferritins. Various peptides or protein were fused to the termini of two ferritins to test if the terminal fusion would affect the functions and self-assembly of the two ferritins. Site-directed mutation was then employed to test the effects of the key residue and heme group on the function and self-assembly of Bfr. [Results] Iron-specific staining on the ferritins separated by native PAGE showed that the Bfr-encoding gene expressed Bfr in all the tested A. fabrum strains, whereas the Dps-encoding gene expressed Dps in none of the tested A. fabrum strains. Complementary experiment with two different Bfr-encoding ORFs (encoding 161 residues and 169 residues) showed that Bfr in the wild type was encoded by the ORF encoding 161 residues. The results demonstrated that terminal fusions with different peptides or protein influenced but did not abolish the function and self-assembly of Bfr. The substitution of Met₆₀, which was predicted to chelate the iron of heme, indicated that heme affected the function and self-assembly of Bfr but was not indispensable. [Conclusion] A. fabrum utilizes Bfr to store iron. The ORF of the Bfr-encoding gene utilizes UUG (a rare start code) as its start code and encodes a Bfr composed of 161 residues. The Dps-encoding gene of A. fabrum expressed in none of the tested conditions. The structures of both Bfr and Dps of A. fabrum are stable enough to withstand the terminal fusion with various peptides or protein, suggesting that both Bfr and Dps nano-cages demonstrate great promise for biotechnological applications.

The pneumococcal vaccines play an indispensable role in defending against various invasive and non-invasive diseases caused by Streptococcus pneumoniae. The capsular polysaccharide is a key antigen, while the impurity residues in the capsular polysaccharide cause side effects of pneumococcal polysaccharide vaccines and conjugate vaccines. As the global demand for high-valent pneumococcal vaccines covering a wide range of serotypes keeps increasing, it is urgent and crucial to develop efficient and scalable production technologies for high-purity capsular polysaccharide antigens. The safety and quality attributes of capsular polysaccharide are influenced by multiple factors encompassing the selection of pathogen strains, formulation of culture media, control of fermentation processes, and purification technologies. Following the concept of Quality by Design (QbD) and the process development path, this article systematically summarizes the knowledge and experience throughout the entire process ranging from upstream strain screening and optimization, refined fermentation process design, to downstream purification, aiming to provide comprehensive and in-depth theoretical guidance and practical strategies for building and improving the production system of capsular polysaccharide.

[Objective] Multipurpose bioorganic fertilizers contribute to the sustainable development of the Carya cathayensis Sarg. industry. This work aims to explore the resources of phosphorus (P)-mobilizing bacteria (PMBs) with plant growth-promoting effects from the rhizosphere soil of C. cathayensis Sarg. [Methods] PMBs were isolated with the dilution-plate coating method and identified based on 16S rRNA gene homology. Moreover, plate and liquid culture tests were conducted to determine their biological functions. [Results] A total of 34 strains of PMBs were isolated from the rhizosphere soil of C. cathayensis Sarg. These PMBs belonged to 10 genera of four phyla: Bacillota, Proteobacteria, Actinobacteriota, and Gracilicutes. Among them, Bacillus (12 strains), Burkholderia (9 strains), and Pseudomonas (5 strains) were the dominant genera, with the strains accounting for 76.47% of the total isolated PMBs. After inoculation of PMBs, the content of soluble P produced by PMBs was 7.01–49.97, 3.61–27.11, 4.56–342.82, 27.71–544.53, and 3.28–27.17 mg/L in the culture media with AlPO₄, FePO₄, Ca₃(PO₄)₂, sodium phytate, and lecithin as the sole P source, respectively. Twenty-three strains were capable of simultaneously mobilize insoluble inorganic and organic P components. Additionally, 20, 7, 23, 12, 10, 14, and 13 strains of PMBs could produce indole-3-acetic acid (IAA), siderophores, extracellular protease, β-1, 3-glucanase, cellulase, phosphatase, and lipase, respectively, among which strains S3-6L and S3-22L exhibited five biological functions. [Conclusion] The PMBs identified in this study possess high P mobilization capability and multiple biological functions, enriching the resources of PMB strains and laying a foundation for the development of efficient, green, and composite microbial fertilizers for C. cathayensis Sarg.

[Objective] To study the role of napF3 in Thermoanaerobacter tengcongensis at different temperatures. [Methods] We constructed ΔnapF3 from T. tengcongensis by homologous recombination and observed the growth of ΔnapF3 at 50 ℃, 60 ℃, 75 ℃, and 80 ℃. Transcriptome sequencing was employed to identify the differentially expressed genes (DEGs) between ΔnapF3 and the wild type (WT) at 75 ℃. real-time PCR was conducted to measure the transcriptional levels of 13 genes and 3 sRNAs in WT and ΔnapF3 at 50 ℃, 60 ℃, 75 ℃, and 80 ℃. [Results] ΔnapF3 was successfully constructed, and it showcased suspended growth at 50 ℃ and 80 ℃ and slow growth at 60 ℃ and 75 ℃. A total of 899 DEGs between WT and ΔnapF3 at 75 ℃ were identified, including 363 genes with up-regulated expression and 536 genes with down-regulated expression. These DEGs were mainly involved in the biosynthesis of valine, leucine and isoleucine, ABC transporters, two-component system, fatty acid synthesis, thiamine metabolism and other pathways. The transcriptional levels of 13 genes and 3 sRNAs related to the thermophilic mechanism changed under specific temperatures. [Conclusion] napF3 plays a role in the thermophilic adaptation of T. tengcongensis.

[Objective] To select the elite strains among the microorganisms isolated from the rhizosphere of Brassica oleracea var. capitata and evaluate the secondary metabolism potential of the strains, laying a solid foundation for mining the microbial resources in the rhizosphere of this plant. [Methods] The roots of B. oleracea var. capitata were collected from Xiannüshan Town in Wulong District of Chongqing. The conventional methods were then used to isolate microbial strains, and one strain of Serratia marcescens was selected for genome sequencing (PacBio RS Ⅱ and Illumina HiSeq) and bioinformatic analysis. The antiSMASH was used for the detection and comparison of biosynthetic gene clusters (BGCs) encoding secondary metabolites. Red/ET recombination was employed to capture the BGC for prodigiosin. [Results] One prodigiosin-producing strain of S. marcescens was isolated from the rhizosphere of B. oleracea var. capitata. The genome of this strain contained 11 putative BGCs (1–11) for secondary metabolites, of which 9 BGCs displayed low similarities to the BGCs encoding known compounds. This result suggested that the strain had great potential of producing novel secondary metabolites. Prodigiosin was identified by HPLC and high-resolution mass spectrometry (HRMS). Heterologous expression of BGC4 resulted in the production of prodigiosin in Escherichia coli. Four common promoters were used to drive the expression of BGC in E. coli, and the highest prodigiosin production was observed with the rpoS promoter. [Conclusion] A prodigiosin-producing strain of S. marcescens was isolated from the rhizosphere of B. oleracea var. capitata. The BGC for prodigiosin was captured from the chromosome of this strain and expressed successfully in the surrogate host E. coli BAP1.