Pollutant transport model with large time-scale and estimation of land-use export coefficients at a watershed level.

The pollutant transport equilibrium in a watershed can be analyzed on a large time scale, and land-use export coefficients can be calculated directly under certain hydrologic and transport conditions, by ignoring hydrologic and transport processes at small space and time scales on hydrologic response units. In this study, the water environment system of a watershed was deconstructed into three parts (source, source-sink, and runoff transport) to construct a pollutant transportation equilibrium model on a large time scale. A watershed with an annual source-sink accumulation of zero was defined as a completely transported watershed; therefore, we derived a completely transported equilibrium equation. The problem of seeking the land export coefficient was converted into a problem of seeking the optimal solution of linear programming, which can be estimated according to the variation in pollutant output processes. The feasibility of the solution can be analyzed using multi-year stochastic rainfall processes. The model was used to analyze the transport equilibrium of chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) upstream of the monitored cross-sections in a watershed, which covered 3145.66 km2. The land export coefficients were calculated according to the model. The model calculations indicated that the watershed was completely transported during perennial years. The calculated export coefficients of COD, TN, and TP for farmland, primary vegetation, and urban land were within the range of general empirical values. The calculated maximum accumulations of COD, TN, and TP were 0.19 × 107, 0.063 × 107, and 0.049 × 106 kg, respectively, for perennial rainfall. PRACTITIONER POINTS: A completely transported watershed was defined, and a model of pollutant transportation equilibrium with large time-scale was constructed. A problem of seeking the optimal solution of a linear programming was designed to estimate the land export coefficient of COD, TN, and TP. The runoff transport and accumulation processes of COD, TN, and TP in a watershed was analyzed.

Physiological, cytological and multi-omics analysis revealed the molecular response of Fritillaria cirrhosa to Cd toxicity in Qinghai-Tibet Plateau.

Fritillaria cirrhosa, an endangered plant endemic to plateau regions, faces escalating cadmium (Cd) stress due to pollution in the Qinghai-Tibet Plateau. This study employed physiological, cytological, and multi-omics techniques to investigate the toxic effects of Cd stress and detoxification mechanisms of F. cirrhosa. The results demonstrated that Cd caused severe damage to cell membranes and organelles, leading to significant oxidative damage and reducing photosynthesis, alkaloid and nucleoside contents, and biomass. Cd application increased cell wall thickness by 167.89% in leaves and 445.78% in bulbs, leading to weight percentage of Cd increases of 76.00% and 257.14%, respectively. PER, CESA, PME, and SUS, genes responsible for cell wall thickening, were significantly upregulated. Additionally, the levels of metabolites participating in the scavenging of reactive oxygen species, including oxidized glutathione, D-proline, L-citrulline, and putrescine, were significantly increased under Cd stress. Combined multi-omics analyses revealed that glutathione metabolism and cell wall biosynthesis pathways jointly constituted the detoxification mechanism of F. cirrhosa in response to Cd stress. This study provides a theoretical basis for further screening of new cultivars for Cd tolerance and developing appropriate cultivation strategies to alleviate Cd toxicity.

Cellulolytic Bacillus cereus produces a variety of short-chain fatty acids and has potential as a probiotic.

Cellulolytic bacteria ferment dietary fiber into short-chain fatty acids, which play an important role in improving fiber utilization and maintaining intestinal health. Safe and effective cellulolytic bacteria are highly promising probiotic candidates. In this study, we isolated three strains of Bacillus cereus, which exhibited cellulolytic properties, from Kele pig feces. To assess the genetic basis of cellulose degradation by the isolates, whole-genome sequencing was used to detect functional genes associated with cellulose metabolism. Subsequently, we identified that the B. cereus CL2 strain was safe in mice by monitoring body weight changes, performing histopathologic evaluations, and determining routine blood indices. We next evaluated the biological characteristics of the CL2 strain in terms of its growth, tolerance, and antibiotic susceptibility, with a focus on its ability to produce short-chain fatty acids. Finally, the intestinal flora structure of the experimental animals was analyzed to assess the intestinal environment compatibility of the CL2 strain. In this study, we isolated a cellulolytic B. cereus CL2, which has multiple cellulolytic functional genes and favorable biological characteristics, from the feces of Kele pigs. Moreover, CL2 could produce a variety of short-chain fatty acids and does not significantly affect the diversity of the intestinal flora. In summary, the cellulolytic bacterium B. cereus CL2 is a promising strain for use as a commercial probiotic or in feed supplement. IMPORTANCE: Short-chain fatty acids are crucial constituents of the intestinal tract, playing an important and beneficial role in preserving the functional integrity of the intestinal barrier and modulating both immune responses and the structure of the intestinal flora. In the intestine, short-chain fatty acids are mainly produced by bacterial fermentation of cellulose. Therefore, we believe that safe and efficient cellulolytic bacteria have the potential to be novel probiotics. In this study, we systematically evaluated the safety and biological characteristics of the cellulolytic bacterium B. cereus CL2 and provide evidence for its use as a probiotic.

Interaction between host G3BP and viral nucleocapsid protein regulates SARS-CoV-2 replication and pathogenicity.

G3BP1/2 are paralogous proteins that promote stress granule formation in response to cellular stresses, including viral infection. The nucleocapsid (N) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) inhibits stress granule assembly and interacts with G3BP1/2 via an ITFG motif, including residue F17, in the N protein. Prior studies examining the impact of the G3PB1-N interaction on SARS-CoV-2 replication have produced inconsistent findings, and the role of this interaction in pathogenesis is unknown. Here, we use structural and biochemical analyses to define the residues required for G3BP1-N interaction and structure-guided mutagenesis to selectively disrupt this interaction. We find that N-F17A mutation causes highly specific loss of interaction with G3BP1/2. SARS-CoV-2 N-F17A fails to inhibit stress granule assembly in cells, has decreased viral replication, and causes decreased pathology in vivo. Further mechanistic studies indicate that the N-F17-mediated G3BP1-N interaction promotes infection by limiting sequestration of viral genomic RNA (gRNA) into stress granules.

A method for fast genomic DNA extraction from saliva saliva and its application / 第二军医大学学报

Objective To explore a fast, effective and noninvasive method of genomic DNA extraction. Methods We compared the genomic DNAs extracted by two DNA extraction methods of potassium iodide (KI) and Kit from saliva (fresh and placed a week at room temperature), and PCR amplifications were done for TP53 and PRB-3 genes from their extracted DNA. Ninety-nine healthy children and adults were recruited and their saliva samples were collected to detect the stability of DNA extracted by KI. Results High quality genomic DNAs were extracted by both methods from the fresh saliva. The DNA yield based on KI was (1.91±0.15) μg, with the D260/D280 being 1.99±0.05, and that of Kit was (2.64±0.34) μg, with the D260/D280 being 1.81±0.02. Although the extracted DNAs had obvious degradation from saliva samples placed for a week at room temperature, the expectant DNA fragments were successfully amplified by PCR for TP53 and PRB-3 genes using these extracted DNAs. Although the genomic DNAs from saliva samples of 99 healthy volunteers by the method of KI showed individual difference (DNA yield was [1.89±0.46] μg), the DNA quality was stable and reliable (D260/D280 was 1.96±0.10). Conclusion KI method for extracting genomic DNA from saliva is not only cheap and highly effective, but also noninvasive, making it suitable for large-scale epidemiological studies.

Research on differentially expressed genes related to substance and energy metabolism between healthy volunteers and splenasthenic syndrome patients with chronic superficial gastritis / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To analyze the metabolic states of the lipids, protein, carbohydrate, and nucleic acid for chronic superficial gastritis patients of splenasthenic syndrome (SS), and to explore the pathogenesis mechanism of SS based on substance and energy metabolisms.</p><p><b>METHODS</b>During June 2004 to March 2005, recruited were four chronic superficial gastritis patients of SS who visited at the First Hospital of Guangzhou University of Chinese Medicine and Guangdong Provincial Hospital of Traditional Chinese Medicine. Four healthy volunteers were recruited from Guangzhou University of Chinese Medicine. Their gastric mucosa was extracted to perform experiments of DNA microarray. The dual-channel DNA microarray data were mined and bioinformatics analyzed by BRB ArrayTools and IPA software.</p><p><b>RESULTS</b>Fifteen genes were involved in substance and energy metabolisms in 20 differentially expressed genes, accounting for 75%.Among these genes, one gene was up-regulated, 14 genes down-regulated, and 11 genes were enzyme gene. Differentially expressed genes related to lipid metabolism included ACAA2 and CYP20A1, manifested as fatty acid catabolism and cholesterol transformation. Genes related to protein metabolism included ALDH9A1, ASL, ASS1, PCY-OX1L, RPS28, UBE2D2, UBXN1, B3GNT1, GCNT1, and PPP1R3C, manifested as decreased amino acid metabolism that may affect the biologic processes such as autonomic nerve, urea cycle, etc., reduced protein synthesis, increased ubiquitination of fault fold proteins, and decreased post-translated modification of glycosylation and dephosphorylation. Genes related to carbohydrate metabolism included PPP1R3C, B3GNT1, and GCNT1, manifested as decreased glycogen and glycan syntheses. Genes related to nucleic acid metabolism included RMI1, SMARCD3, and PARP1, manifested as degraded DNA duplication and transcription, and increased DNA damage repair.</p><p><b>CONCLUSIONS</b>The metabolisms of the lipids, protein, carbohydrate, and nucleic acid in chronic superficial gastritis patients of SS obviously decreased, manifested mainly as down-regulated enzyme gene expression. We inferred that these might be one of the vital pathogenesis mechanisms for nutrition dysmetabolism of SS.</p>