Glucose-1-phosphate is a key precursor for starch biosynthesis of photoautotrophs. Phosphoglucomutases (PGMs) belonging to the phosphohexomutase family have a high conserved characteristic and perform the interconversion between glucose-6-phosphate and glucose-1-phosphate to regulate the starch biosynthesis. Compared with the higher plants, microalgae possess unique photosynthetic systems. Additionally, some microalgae strains can utilize organic carbon sources to produce valuable biomass by heterotrophic or mixotrophic cultivation, which might endow PGMs with specific structural features and biological functions in starch metabolism to regulate the levels of carbon fixation by photosynthesis, carbohydrate metabolism, and other pathways in microalgae. This article summarizes the molecular characteristics, functions, and activity regulation of PGMs for microalgae. Moreover, this article elucidates the potential mechanisms by which PGMs regulate microalgae starch synthesis to influence intracellular protein and lipid metabolic pathways. This review lays a theoretical foundation for microalgae carbon sequestration and the value-added utilization of microalgae resources, contributing to the achievement of China's "dual-carbon" goals.

[Objective] To investigate the effects of a metabolite cocktail composed of indole-3-propionic acid (IPA), sodium butyrate (SB), and valeric acid (VA) of gut microbiota on the proliferation of hepatocellular carcinoma cells. [Methods] The human hepatocellular carcinoma HepG2 cells were cultured in vitro and treated with the cocktail at different concentrations (1×, 2×, 3×, 4×, and 5×). The total cholesterol (TC) and triglyceride (TG) levels in the cells were determined by the total cholesterol and triglyceride assay kits. The Cell Counting Kit-8 (CCK-8) and colony formation assays were employed to examine the cell proliferation. Twelve BALB/c athymic nude mice were randomized into a control (Ctrl) group and a treatment (Treat) group and then subjected to subcutaneous injections of HepG2 cells. The tumor size was measured every three days, and the tumor volume and tumor inhibition rate were calculated. When the tumor volume reached 100 mm³, the mice in the Ctrl group were administered with sterile water by gavage daily, while those in the Treat group received the cocktail via gavage until euthanized under anesthesia. After 27 days of treatment, the body weights of mice in both groups were measured, and tumors were excised and weighed, with the tumor weight/body weight ratio calculated. The content of Ki-67 protein in the tumors was determined by immunohistochemical (IHC) staining, and the lipid accumulation within tumor cells was assessed by Oil Red O staining. [Results] The cocktail of IPA, SB, and VA lowered the levels of TC and TG in hepatocellular carcinoma HepG2 cells and exerted an inhibitory effect on the proliferation of HepG2 cells. Both CCK-8 and colony formation assays indicated that the cocktail inhibited the proliferation of HepG2 cells in a dose-dependent manner. The oral administration of the cocktail inhibited the growth of hepatocellular carcinoma cells, as evidenced by smaller and lighter tumors and lower tumor weight/body weight ratios in the Treat group than in the Ctrl group (Ctrl: 723 mm³, 0.47 g, 22.23%; Treat: 526 mm³, 0.32 g, 16.65%). IHC and Oil Red O staining further demonstrated reductions in Ki-67 expression and lipid accumulation in the mice administered with the cocktail via gavage. [Conclusion] The cocktail of IPA, SB, and VA can inhibit the proliferation and suppress the lipid synthesis of hepatocellular carcinoma cells.

CRISPR-Cas is a defense system ubiquitous in bacteria and archaea. It has been successfully applied in genome editing in a variety of organisms. At present, CRISPR-Cas9 and CRISPR-Cas12a are the most widely used genome editing tools. However, the large protein sizes of Cas9 and Cas12a (more than 1 000 amino acids (aa)) hinder their delivery. TnpB and IscB (about 400 aa) encoded by the transposon family are considered ancestors of Cas12 and Cas9, respectively, whereas their functions are revealed just recently. They are named as obligate mobile element-guided activity (OMEGA), with the associated RNA named ωRNA. Since then, the OMEGA system has become one of the research hotspots in genome editing. OMEGA systems are diverse, with wide distribution in all the three domains of life. The in-depth research on the OMEGA system will aid in the development of new genome editing tools that are streamlined, efficient, and safe. Here, we reviewed the discovery history, structural characteristics, mechanisms of cleavage, and genome editing applications of OMEGA systems, aiming to lay a foundation for the development and optimization of genome editing tools.

[Objective] A facultative anaerobic bacterium Klebsiella sp. CW-D3T utilizing sulfate as the terminal electron acceptor for anaerobic respiration was used for degradation of target pollutants in the system with phenanthrene (PHE)-Cd²⁺ co-contamination. The response mechanism of the strain to different Cd²⁺ concentrations in the sulfate reduction system and the anaerobic metabolic pathways of the strain for degrading PHE were studied. [Methods] A sulfate reduction system with an initial sulfate concentration of 20 mmol/L was developed to enhance the growth and metabolic activity of functional bacteria and improve the bacterial performance for remediating PHE-Cd²⁺ co-contamination. The changes in extracellular polymer secretion and the vibrational characteristics of characteristic peaks were analyzed to explore the cellular responses to different Cd²⁺ concentrations. Furthermore, qualitative and quantitative analyses of the metabolic products of PHE in the sulfate reduction system were conducted by GC-MS and HPLC. [Results] In the presence of 0.5–50.0 mg/L Cd²⁺, the sulfate reduction system of Klebsiella sp. CW-D3T enhanced the remediation efficiency of target compounds, with the PHE and Cd²⁺ removal rates above 70.00% when the initial Cd²⁺ concentration was below 10 mg/L. As the concentration of Cd²⁺ increased, the secretion of extracellular polysaccharides in extracellular polymeric substances (EPS) was more than that of extracellular proteins, and the intensity of characteristic peaks of polysaccharides and protein functional groups on the surface of bacterial cells was enhanced. The initial activation of PHE in the sulfate reduction system tended to favor carboxylation to produce 2-phenanthroic acid under Cd²⁺ stress. When the initial Cd²⁺ concentrations were 10 mg/L and 50 mg/L, the content of 2-phenanthroic acid peaked at 15.56 μg/L and 10.23 μg/L on day 5, respectively, which decreased by 27.56% and 52.37% compared with that of the control group without the addition of Cd²⁺. Cd²⁺ stress significantly affected the 2-phenanthroic acid content within the cycle and at the end of the cycle. [Conclusion] The biodegradation efficiency of PHE by Klebsiella sp. CW-D3T was significantly improved when sulfate was used as an electron acceptor in the presence of Cd²⁺. The extracellular polysaccharides and proteins played a positive role in enhancing the microbial tolerance to Cd²⁺ stress by regulating the detoxification process.

Depression is a prevalent affective disorder exerting negative impacts on an individual's emotional and cognitive functions and is commonly complicated with other diseases. As depression is affecting increasingly younger populations, it poses a serious challenge to the mental health initiatives in China. In recent years, the relationship between depressive symptoms and gut microbiota has garnered increasing attention, fueled by the deepening research on gut microbiota. Lactulose, a medication aimed at promoting gut health and known for its potential benefits on emotional and cognitive functions, has sparked interests regarding its clinical application in ameliorating depressive symptoms. This article reviews the clinical research findings on the efficacy of lactulose in alleviating depressive symptoms and outlines the potential mechanisms through which lactulose may mitigate these symptoms. Furthermore, this article offers a perspective on the mitigation of depressive symptoms through the gut-brain axis.

Levilactobacillus brevis is a common species of lactic acid bacteria mainly detected on the surface of plant stems and leaves and in pickles, dairy products, and intestines. With excellent physiological functions, L. brevis is a potential probiotic species. With the rise of genomics, it is of great significance to reveal the genetic characteristics and functional gene properties of L. brevis at the gene level for application of this bacterium. This paper reviews the genetic background and major functional genes of L. brevis, aiming to lay a theoretical foundation for the application of L. brevis.

Type 2 diabetes mellitus (T2DM) stands as a chronic metabolic disorder posing a challenge to global public health, owing to its widespread prevalence. The intricate interplay between gut microbiota and the onset and progression of T2DM, along with the potential therapeutic benefits of modulating gut microbiota, has emerged as a focal point in contemporary research. Recent studies have underscored the capacity of traditional Chinese medicine to ameliorate T2DM by inducing alterations in gut microbiota. Nevertheless, the precise mechanisms underlying the pharmacological actions of traditional Chinese medicine via gut microbiota regulation remain elusive. The diverse bioactive compounds in traditional Chinese medicine play pivotal roles in eliciting its pharmacological effects. This article systematically reviews the advancements in the research concerning the modulation of gut microbiota for T2DM intervention by a spectrum of bioactive components in traditional Chinese medicine, encompassing polysaccharides, alkaloids, flavonoids, saponins, and other compounds. The objective of this review is to furnish a comprehensive theoretical framework supporting the preventive and therapeutic potential of traditional Chinese medicine in T2DM management, thereby significantly contributing to the modernization of traditional Chinese medicine.

Monocarboxylates such as lactate, pyruvate, and ketone bodies play an important role in the metabolic activities of organisms. As a monocarboxylate transporter, MpMch2 is mainly responsible for the transmembrane transport of monocarboxylates and the maintenance of glucose metabolism balance.[Objective] To analyze the functions of MpMch2 in Monascus purpureus. [Methods] The MpMch2 in M. purpureus Mp-21 was replaced with the hygromycin gene by homologous recombination to construct the deletion strain ∆MpMch2. The colony and cell morphology of Mp-21 and ∆MpMch2 on different media was observed, and the yield of monascus pigment, γ-aminobutyric acid, conidia and ascospores were determined. The expression levels of genes related to conidia and γ-aminobutyric acid were determined by RT-qPCR. [Results] There was no significant difference in the colony morphology between the wild type and ∆MpMch2 on different media. After knockout of MpMch2, the yields of conidia, ascospores, Monascus pigments, and γ-aminobutyric acid decreased, and the expression levels of related genes were down-regulated. [Conclusion] MpMch2 positively regulated the development of conidia and ascospores and the production of Monascus pigments and γ-aminobutyric acid.

[Objective] Over 7 million people die from bacterial infections every year due to the inappropriate or untimely use of antibiotics. Antimicrobial susceptibility test (AST) is a routine method guiding antibiotic therapy in clinical practice, while the existing methods have limitations as they require at least 16–20 h to get the results. We aimed to develop a novel rapid AST method based on bacterial morphology analysis, which can improve the diagnosis efficiency and provide timely treatment for the patients with bacterial infections, especially for urgent cases. [Methods] We developed an in-situ time-lapsed imaging (ISM-TLI) technique for microcolonies by combining bacterial incubation, in vitro antibiotic treatment, microscopic imaging, and image processing algorithm. The combination of the imaging device with the algorithm enabled the tracing of the morphological changes of colonies treated with different concentrations of antibiotics in-situ and the rapid obtainment of AST results. [Results] This technique worked effectively for both Gram-positive and Gram-negative bacteria and could determine the minimum inhibitory concentration (MIC) within 2 h, with the results in agreement with those obtained with the clinical gold standard method. [Conclusion] Our rapid AST technique significantly reduced the turn-around-time for obtaining the AST profile and had great potential for AST of a wide range of other strains.

Agar is one of the important components in the cell wall of red algae. The biodegradation of agar affects marine ecological processes, such as nutrient recycling, succession of large seaweed communities, heavy metal pollution, and carbon sequestration. In addition, the degradation products of agar demonstrate great application potential in aquaculture, agriculture, medicine, health products, bioenergy, etc. Therefore, the biodegradation of agar and its ecological and application values have become research hotspots in recent years. This article reviews the research progress in the significance of agar degradation, microbial agarases, and agar metabolic pathways, providing theoretical support for the research on the ecological effects and comprehensive utilization of the agar from red algae.