Sheng wu gong cheng xue bao = Chinese journal of biotechnology最新文献

To address the issues of low efficiency and susceptibility to high-concentration pollutants in nitrite nitrogen (NO₂^--N) removal in existing technologies, screening functional bacterial strains with high NO₂^--N removal capacity has become one of the effective solutions. This study focused on a strain, Paracoccus shandongensis wg2, isolated from activated sludge in the wastewater of propylene oxide saponification, investigating its nitrogen removal mechanism through nitrogen balance analysis and isotopic tracing. The results demonstrated that the strain adopted a nitrogen removal metabolic pathway belonging to the nitrite denitrification type. Under anaerobic conditions, the strain exhibited remarkable nitrite nitrogen (NO₂^--N) removal efficiency, achieving over the elimination rate over 98.00% within 48 h. Through process parameter optimization, the optimal denitrification conditions were determined as follows: glucose as the carbon source, C/N ratio of 5, initial pH 7.0, temperature of 30 ℃, and rotation speed of 170 r/min. Under these optimized conditions, strain wg2 accomplished complete NO₂^--N (55 mg/L) removal within 10 h. This research not only provides a microbial resource for the biological treatment of nitrogen-containing wastewater but also offers significant practical guidance for addressing high-concentration nitrite wastewater.

Immunoglobulins are adaptive immune effector molecules unique to jawed vertebrates. Their remarkable diversity relies on mechanisms including V(D)J recombination, somatic hypermutation, and class switch recombination. These processes are orchestrated by a variety of key enzymes, such as recombination-activating gene proteins, terminal deoxynucleotidyl transferase (TdT), activation-induced cytidine deaminase, and DNA glycosylases. These enzymes not only play critical roles in the formation of antigen receptor diversity but have also been widely developed as useful tools for basic biological research. This review summarizes the molecular mechanisms underlying antigen receptor diversification in mammals, discusses recent progress in antibody screening and application, and highlights the latest advances in the use of TdT, cytidine deaminases, and DNA glycosylases in synthetic biology. These studies provide important theoretical support and new directions for fundamental research and technological innovation in biotechnology and medicine.

Patatin-like phospholipase domain-containing 3 (PNPLA3) I148M polymorphism (SNP rsID: rs738409; PNPLA3-I148M), a key genetic susceptibility factor for metabolic-associated fatty liver disease (MAFLD), is closely associated with disease progression. However, its mechanism in liver fibrosis remains to be elucidated. This study aimed to investigate the effects of PNPLA3-I148M overexpression on cholesterol metabolism, mitochondrial function, and fibrosis in the liver. We constructed the mouse models specifically overexpressing either the wild-type PNPLA3 (PNPLA3-WT) or PNPLA3-I148M in the liver. Liver fibrosis was induced via a high cholesterol-methionine and choline deficient (HC-MCD) diet. Our results showed that compared with the PNPLA3-WT group, mice overexpressing PNPLA3-I148M exhibited significantly elevated levels of total cholesterol, triglycerides, and free cholesterol, increased lipid droplet accumulation, and exacerbated steatosis and fibrosis in the liver. Mechanism studies revealed that PNPLA3-I148M interfered with cholesterol esterification and efflux by suppressing the expression of acyl-coenzyme A: cholesterol acyltransferase 1 (ACAT1) and ATP-binding cassette transporter G1 (ABCG1). This led to abnormal accumulation of free cholesterol in the liver, activated dynamin-related protein 1 (DRP1), and ultimately induced mitochondrial dysfunction and the expression of fibrosis-related genes. These findings provide important in vivo evidence and reveal a potential molecular mechanism by which PNPLA3-I148M promotes the development of liver fibrosis, laying the groundwork for developing precision therapeutic strategies targeting PNPLA3-I148M in MAFLD.

Sterols play a crucial role in the growth and development of organisms, as well as in the construction of cell membranes. The biosynthesis of sterols is a complex metabolic process involving multiple enzymatic reactions. The removal of two methyl groups at the C-4 position by the sterol-C4-methyloxidase-like (SC4MOL) is an important step in sterol functionalization. This paper provides a systematic review of the critical role of SC4MOL in sterol biosynthesis. It specifically elaborates on SC4MOL in terms of the composition, catalytic mechanism, and functional diversity across different organisms in processes such as growth, development, and resistance to diseases and stress. The review lays a foundation for further research into the regulation of sterol metabolism.

Enzyme-mediated degradation of plastics is considered as a promising solution for addressing escalating plastic pollution. Extensive studies have identified diverse plastic-degrading enzymes from typical habitats, extreme environments, and different hosts. However, the short co-evolution period between microbes and plastics limits the natural evolution of specific plastic-degrading enzymes. The identified plastic-degrading enzymes mainly belong to the carbohydrate esterase (CE) and auxiliary activity (AA) enzyme families, being involved in lignin degradation. Consequently, lignin degradation-related enzymes represent a promising resource for the discovery of novel plastic-degrading enzymes. The available studies on the catalytic mechanisms and applications of plastic-degrading enzymes mainly focused on IsPETase and leaf-branch compost cutinase (LCC). Systematic insights into non-hydrolytic plastic-degrading enzymes remain scarce. This review summarizes the types and catalytic mechanisms of plastic-degrading enzymes related to C-O and C-C backbone plastics, and advancements in their screening strategies, engineering modifications, and applications over the past five years. These findings contribute to the collaborative evolution of enzyme research in terms of mechanisms and application innovation. Furthermore, this review establishes a theoretical framework for plastic pollution control.

The ubiquitin-proteasome system (UPS) serves as the central mechanism for protein degradation in eukaryotic cells. Deubiquitinases (DUBs), which maintain protein stability and function by removing ubiquitin chains play a key role in protein cycling. Consequently, a DUB-targeting chimera (DUBTAC) technology has emerged. A DUBTAC consists of three components: a protein-targeting ligand, a DUB recruiter, and a linker connecting them. A DUBTAC can simultaneously bind to its targeted protein and DUB and induce the DUB to cleave the ubiquitin chains, thereby restoring the protein function by stabilizing the target protein. The DUBTAC technology provides a novel research strategy involving targeted protein stabilization for conventionally "undruggable" proteins that are abnormally degraded. Compared with other mature technologies, such as proteolysis-targeting chimera (PROTAC) and molecular glue degrader technologies, the DUBTAC technology has the unique advantages of targeting and stabilizing tumor suppressors, thus showing high potential for cancer therapy. However, it is still in the early stage of development with few systematic summaries of recent research achievements. This review introduces the basic concepts, critical design, and research considerations of DUBTACs, summarizes the latest research advances in DUBTAC technology for antitumor drug development, and discusses the development strategies and clinical application prospects of DUBTACs in the future, aiming to provide more directions for research on this technology.

Soybean isoflavones (SIFs), a class of polyphenolic compounds, exhibit a range of beneficial biological activities, including immunomodulation, antioxidant effects, anticancer properties, and the promotion of reproduction and growth. Their potential application in animal husbandry has garnered increasing research interest. However, natural SIFs are predominantly present as biologically inactive glycosides, with only minimal amounts existing in the highly active aglycone form. Enhancing their bioavailability, therefore, necessitates a biotransformation process. Microbial fermentation emerges as an efficient, eco-friendly, and cost-effective strategy for this purpose, capable of transforming inactive glycosides into bioactive aglycones and other metabolites through reactions such as deglycosylation, demethylation, dehydroxylation, and reduction. This review elucidates the structural characteristics and metabolic pathways of SIFs, summarizes recent advances in their microbial transformation by various microorganisms (e.g., lactic acid bacteria, fungi, and Bacillus species), and critically assesses the efficacy and underlying mechanisms of SIFs in enhancing animal productivity, reproductive performance, and immune function. The aim is to provide valuable insights for the advanced application of SIFs in the animal husbandry and food industries.

D-amino acids, chiral molecules with unique physiological activities, present widely distribution in microorganisms, plants, and animals. With the deepening of research, D-amino acids are playing increasingly important roles in food, pharmaceuticals, agrochemicals, cosmetics and other fields. However, the natural abundance of D-amino acids is low. Chemical synthesis methods suffer from low stereoselectivity, serious environmental pollution, and high production costs, which limit their industrial application. Enzymatic synthesis has emerged as a cutting-edge research focus for D-amino acid production due to its high stereoselectivity, mild reaction conditions, and environmental friendliness. Currently, enzymes commonly used for D-amino acid synthesis include D-amino acid dehydrogenase, L-amino acid oxidase, D-amino acid aminotransferase, D-aminoacylase, D-hydantoinase, and D-carbamoylase. These enzymes employ various mechanisms to convert substrates or resolve racemic mixtures, or establish multi-enzyme cascade reactions to synthesize diverse D-amino acids and their derivatives. This review summarizes the latest advances in the enzymatic synthesis of D-amino acids, explores the catalytic mechanisms and optimization strategies of various enzymes, and examines the performance of these enzymes in practical applications, providing theoretical support and technical guidance for the efficient and green synthesis of D-amino acids.

Petrochemical contaminants pose serious threats to the environment, and bioremediation is one of the main approaches for the remediation of petrochemical contamination. However, conventional bioremediation processes often have limitations, such as prolonged duration and low efficiency. There is an urgent need to develop new bioremediation technologies to improve the degradation effect on petrochemical contaminants. Constructing engineered microorganisms through synthetic biology for contaminant degradation has emerged as a cutting-edge technology and a popular research focus to address environmental challenges. This review introduces the hazards of petrochemical contamination and the shortcomings of existing remediation technologies and summarizes the research progress in biosensors, engineered strains for degradation, and synthetic microbial communities for petrochemical contamination remediation. Subsequently, it expounds on the problems existing in engineered microorganisms during the remediation and proposes possible solutions. Finally, this paper makes an outlook on the application prospects of synthetic biology in this field. The continuous development of synthetic biology in the field of environmental remediation is expected to further improve the efficiency of bioremediation, achieve the best remediation effect, and provide more feasible solutions for the green development and environmental protection work in China.

The growing prevalence of type 2 diabetes mellitus (T2DM) poses a great economic burden on the society. The pathogenesis of T2DM is a combined effect of two factors: defective insulin secretion in pancreatic β cells and peripheral insulin resistance in skeletal muscle, liver, and adipose tissue. Although extensive efforts have been made to investigate the pathogenesis of T2DM, the precise molecular mechanisms of the onset and progression of T2DM remain incompletely understood. Accumulating evidence suggests that post-translational modifications (PTMs) play critical roles in the development of T2DM and its complications. With the development of analytical techniques, mass spectrometry (MS), and quantitative methodologies, it is feasible to systematically characterize PTM dynamics under both physiological and T2DM conditions, thereby giving insights into the pathogenesis of T2DM and its complications. Here, we discuss the roles of PTMs including phosphorylation, acylation (acetylation, malonylation, and succinylation), O-linked N-acetylglucosamine (O-GlcNAc), advanced glycation end products (AGEs), and protein tyrosine nitration (PTN) in the pathological changes of T2DM and its complications. Furthermore, we review recent progress in the applications of post-translational modification proteomics (PTMomics) for elucidating the molecular mechanisms underlying T2DM and its complications.