Biomedical subjects

Xiang-Dong Chen

Publications and source records attributed to Xiang-Dong Chen.

5 recordsLinked to original sources

PubMed2026

Halorubrum marinum sp. nov., Halorubrum rarum sp. nov., Halorubrum wangae sp. nov., Halorubrum shenae sp. nov., and Halorubrum zhoui sp. nov., halophilic archaea from coastal tidal flats, a saline lake, and a marine solar saltern.

Five novel halophilic archaeal strains, designated DTA46T, DTA98T, HHNYT27T, N11T, and SY-15T, were isolated from diverse saline environments across various regions of China. Amplicon and metagenome analyses revealed that three amplicon reads were affiliated with strains DTA46T, HHNYT27T, and N11T while two MAGs related to strains N11T and SY-15T. The sequence similarities among these five strains and current species of the genus Halorubrum were 93.1%-99.1% and 86.0%-95.9% judged by 16S rRNA and rpoB' genes, respectively. Phylogenomic and comparative genomic analyses revealed their close affiliation with Halorubrum. The average nucleotide identity (ANI), digital DNA-DNA hybridization (dDDH), and average amino acid identity (AAI) values between these strains and existing Halorubrum species ranged from 74.9%-93.6%, 22.3%-58.3%, and 68.3%-93.7%, respectively. All are below the recommended thresholds for species delineation, which supports their classification as novel taxa. The growth characteristics of strains DTA46T, DTA98T, HHNYT27T, N11T, and SY-15T were determined as follows: temperature range 20-60 °C (optima: 35, 37-42, 37, 35, and 42 °C), NaCl concentration 1.4-5.5 M (optima: 2.6, 3.1, 3.1, 3.1, and 5.1 M), and pH range 5.5-9.5 (optima: 8.0, 8.0, 7.0, 7.5, and 7.0). Based on the polyphasic characterization integrating phenotypic, chemotaxonomic, phylogenetic, and phylogenomic evidence, strains DTA46T, DTA98T, HHNYT27T, N11T, and SY-15T are proposed to represent five novel species of the genus Halorubrum, for which the names Halorubrum marinum sp. nov., Halorubrum rarum sp. nov., Halorubrum wangae sp. nov., Halorubrum shenae sp. nov., and Halorubrum zhoui sp. nov. are designated, respectively.

Phylogeny↗

PubMed2006

Analysis of plasmid DNA damage induced by melanin with capillary electrophoresis.

Dilute linear poly(N-isopropylacrylamide) (PNIPAM) in Tris-Mes-EDTA (TME) buffer was used as sieving matrix for capillary electrophoresis (CE) of plasmid DNA and plasmid topological isomers induced by melanin in uncoated capillary. At the optimized condition of 0.1% (w/v) PNIPAM in TME buffer, base line separation of the plasmid DNA ladder (2-12 kbp) was achieved within 15 min. Three positive clones with inserts of 468, 1147 and 1566 bp can be distinguished from the plasmid pUC 18 vector within 13 min. The migration order of the plasmid topological isomers in the dynamic coating matrix was confirmed by the enzymatically prepared and UV-induced plasmids. The covalently closed circular form appeared firstly, followed by the linear plasmid form and then the open circular form. The effect of bacterial melanin obtained from Pseudomonas maltophilia AT18 on plasmid pUC 18 was investigated by CE in uncoated capillary in vitro. Plasmid pUC 18 incubated with either melanin or copper ions alone sustained little DNA damage. The combination of melanin with Cu(II) can cause the plasmid pUC 18 conformational changes from covalently closed circular form to open form. Understanding the damage effect of melanin with copper ions on DNA would be important for the melanin-related application, such as photoprotective antioxidant in protecting the skin from cancer, pathophysiology research in clinic. The investigation of melanin induced plasmid conformational changes by CE in uncoated capillary also revealed that the application of the dynamic coating matrix could be extended to the study of plasmid conformational changes in other plasmid-based biological technologies.

Acrylic Resins↗

PubMed2004

Effect of Shenfu Injection (ginesenoside and aconite alkaloid) on the apoptosis of intestinal mucosal epithelial cells and its mechanism during ischemia-reperfusion in rats.

OBJECTIVE: To investigate the effect of Shenfu Injection (SF, ginesenoside and aconite alkaloid) on the apoptosis of intestinal mucosal epithelial cells during ischemia-reperfusion in rats and its potential mechanisms. METHODS: Ischemia-reperfusion model was established in rats. Twenty-four rats were divided into 3 groups with 8 rats in each, eg, ischemia-reperfusion (I/R) group, SF-treated group, and control group. In both SF and I/R groups, the superior mesenteric artery was closed with forceps for 1 hour and then reperfused for 2 hours. Either SF (3 ml/kg, SF group) or normal saline (I/R and control groups) was injected intravenously and continuously for 5 ml/kg with a micropump before the superior mesenteric artery was closed. The superior mesenteric artery was not closed for animals in control group. The expression of casapse-3 and Fas, and the level of TNF-alpha and pathological changes of the ileal mucosal tissue were assayed. RESULTS: (1) The number of apoptosis cells increased obviously in I/R group and was significantly higher than that in SF and control groups (P<0.05). (2) The expression of caspase-3, Fas, and TNF-alpha was significantly higher in I/R group than SF and control groups (P<0.01); however, there was not significant difference in the expression of capase-3 between control group and SF group. There was a positive correlation between the expression of caspase-3, Fas, and TNF-alpha, and the number of apoptosis cells. (3) Under light microscope, intestinal mucosal impairment was found milder in SF group than I/R group (P<0.05). CONCLUSIONS: SF can depress the apoptosis of intestinal mucosal epithelial cells during ischemia-reperfusion by restraining the expression of TNF-alpha, Fas, caspase-3, and accordingly alleviate the ischemia and reperfusion injury of intestinal mucosal epithelial cells.

Animals↗

PubMed2003

Analysis of genetic variation in Ganoderma lucidum after space flight.

A modified CTAB method was used in the extraction of total cellular DNA of Ganoderma lucidum. Four strains Cx, Ch, C3 and C4, and their counterparts, four space flown strains Sx, Xh, S3 and S4, were analysed by amplified fragment length polymorphism (AFLP) with several primer combinations. Polymorphic bands were detected between Sx and Cx, S3 and C3, respectively. Somatic incompatibility tests further confirmed their heterogeneity. However, no disparity between Sh and Ch, S4 and C4 was detectable. The results suggest that spaceflight may be used to accelerate breeding of Ganoderma lucidum strains for commercial cultivation.

Agriculture↗

PubMed2003

[Horizontal gene transfer].

In this paper the conception of horizontal gene transfer (HGT) was introduced,and main mode of HGT was also enumerated as follows: HGT by medium such as plasmid and virus etc., and the HGT without any medium. The transfer of genes from one species to another especially between remote species was emphasized by the information from genome sequencing. The problems about evolution phylogenies and safety of GEMs (gene engineered microorganisms) for HGT were discussed.

English Abstract↗