Biomedical subjects

Chenggang Zhang

Publications and source records attributed to Chenggang Zhang.

At least 19 recordsLinked to original sources

PubMed2006

Characterization of the receptors for axon guidance factor netrin-4 and identification of the binding domains.

Netrins are a family of secreted protein related to laminin and act as tropic cues directing axon growth and cell migration during neural development. Netrin-4 is a novel member of netrin family recently identified in the vertebrate with neuritis elongation promoting activity; however, the receptors for netrin-4 are still unknown. To better understand the function and signal transduction pathway of netrin-4, the potential receptors for netrin-4 were studied in this paper. The netrin-4 protein was prepared by introducing a eukaryotic expression vector with a secretable alkaline phosphatase tag (AP4) into COS7 cells to allow the expression of AP4-netrin4 fusion protein. Axon guidance activity of netrin-4 was confirmed by using the cortical explants. After incubation with cultured primary cortical neurons, the neurons were distinctly labeled by the AP4-coupled netrin-4 ligands. In contrast, the binding activity of AP4-netrin4 to neurons could be completely competed by the exogenously expressed netrin-4 protein without AP4 tag, indicating specificity of netrin-4 binding to the potential receptors. Moreover, netrin-4 could also bind to CHO cells transfected with the plasmids expressing two known receptors for netrin-1, Deleted in Colorectal Cancer (DCC) and UNC5 homolog 1 (UNC5H1) respectively. As there are three domains in netrin-4, we further tried to narrow down the region containing binding sites with the receptors. Interestingly, only the N-terminal domain (LNT) could bind to DCC and UNC5H1. A further ligand-receptor binding analysis showed that both the N- and the C-terminal domain (NCT) but not the EGF-like (EGFL) domain of netrin-4 could bind to the surface of cultured primary neurons, indicating the existence of novel receptors for netrin-4. After competed by netrin-4, we confirmed that the binding of AP tagged netrin-4 domains to neurons were also netrin-4 dependent. The binding activity of the N-terminal domain of netrin-4 is about 3-fold higher than that for the C-terminal domain. In summary, our data here indicated that the two known receptors for netrin-1, DCC and UNC5H1, are also receptors for netrin-4, while only LNT but not EGFL and NCT is the key domain for specific binding. In addition, there are novel receptors for netrin-4, where both LNT and NCT but not EGFL are key domains for binding.

Alkaline Phosphatase↗

PubMed2006

Increased neuroglobin levels in the cerebral cortex and serum after ischemia-reperfusion insults.

Neuroglobin (NGB) is a newly discovered protein localized in neurons of the central and peripheral nervous systems in vertebrates. It functions to bind, store, and facilitate the utilization of oxygen in neuronal cells. Recent studies suggest that it may modulate hypoxic and ischemic injury. The major goal of the present study is to characterize the dynamic changes of NGB protein in the brain and serum in a global forebrain ischemia-reperfusion model using gerbils. The sensitivity and validity of serum NGB as a potential biomarker for brain injury were further evaluated. Global cerebral ischemia-reperfusion models were induced by bilateral carotid occlusion for 20 min followed with 2-, 8-, 16-, 24-, 48-, or 72-h reperfusion in forty-six Mongolian gerbils. Sham-operated and operated animals were sacrificed at the designated time after reperfusion. Brains were fixed for immunocytochemical study to evaluate the time-dependent expression of NGB, and the concentration of NGB in serum was measured by enzyme-linked immunosorbent assay. Our results showed that the expression of NGB was upregulated in the cerebral cortex but significantly downregulated in the hippocampus from 2 to 72 h of reperfusion after 20 min of bilateral common carotid arteries occlusion. The concentration of NGB in serum was significantly increased at 8 h and reached a peak at 48 h of reperfusion. There is a significant correlation between NGB levels in the serum and severity of neuronal damage in the gerbil brain. In summary, the upregulation of NGB in cerebral cortex and downregulation in hippocampus after reperfusion insults in the gerbil brain are consistent with the fact that cerebral cortex is more tolerant to hypoxic or ischemic injury than the hippocampus. Moreover, the changes of NGB levels in serum may be used to monitor the extent of brain damage in ischemic brain diseases.

Analysis of Variance↗

PubMed2006

HUPO Brain Proteome Project: summary of the pilot phase and introduction of a comprehensive data reprocessing strategy.

The Human Proteome Organisation (HUPO) initiated several projects focusing on the proteome analysis of distinct human organs. The Brain Proteome Project (BPP) is the initiative dedicated to the brain, its development and correlated diseases. Two pilot studies have been performed aiming at the comparison of techniques, laboratories and approaches. With the help of the results gained, objective data submission, storage and reprocessing workflow have been established. The biological relevance of the data will be drawn from the inter-laboratory comparisons as well as from the re-calculation of all data sets submitted by the different groups. In the following, results of the single groups as well as the centralised reprocessing effort will be summarised and compared, showing the added value of this concerted work.

Animals↗

PubMed2006

Acyl migration during debenzylation of 1,3-di-O-benzyl-2-O-acylglycerols.

In investigating the preparation of 2-acylglycerol by debenzylation of 1,3-di-O-benzyl-2-O-acylglycerol, twelve 1,3-di-O-benzyl-2-O-acylglycerols were synthesized. 2-O-Acyl moieties with one or more protons at the carbon atom adjacent to carbonyl group were found to migrate from C-2 to C-1 of the glycerol moiety during hydrogenation under Pd/C at room temperature.

Diglycerides↗

PubMed2006

[Soil microbial ecological process and microbial functional gene diversity].

Soil microbes in terrestrial ecosystem carry out a series of important ecological functions, such as geo-chemical cycling of elements, degradation of pollutants, and buffering to the acute changes of environment, etc. Soil microbial ecological function has a close relation with soil function, and the changes in the structure and composition of soil microbial populations can directly affect the realization of soil function. Through their produced enzymes, soil microbes take part in a series of metabolic activities, and the functional genes of coded enzymes are the functional markers of microbes. In recent ten years, molecular ecology focusing on the functional gene diversity has been developed rapidly, which gives us a new cut-in point to understand soil microbial ecological function from the point of functional gene. This paper reviewed the research advances in the functional gene diversity correlated to soil microbial ecological function, with the perspectives in this field discussed.

Bacteria↗

PubMed2005

Impacts of methamidophos, copper, and their combinations on bacterial community structure and function in black soil.

The potential ecotoxicologial risks of methamidophos, copper, and their combinations on microbial community of black soil ecosystem in the Northeast China were assessed in species richness and structures by using 16S rDNA-PCR-DGGE analysis approach, and functional characteristics at community levels by using BIOLOG(GN) system analysis method as well as two conventional methods (DHA and SIR). All results of DGGE banding fingerprint patterns (amplified by bacterial specific 16S rDNA V3 high variable region universal primer) indicated that the species richness of bacterial community in tested soil was significantly decreased to different extents by using different concentrations of single methamidophos, copper, especially some of their combinations had worse effects than their corresponding single factors. In addition, the structures of soil bacterial community had been disturbed under all stresses applied in this study because of the enrichment of some species and the disappearance of other species from the bacterial community. The effects of the single factors with lower concentrations on the community structure were weaker than those with higher concentrations. Moreover, the bacterial community structures under the combined stresses of methamidophos and copper were significantly different from those of control and their corresponding single factors. The change of DHA and carbon source substrate utilizing fingerprint patterns based on BIOLOG(GN) system were two relatively sensitive directors corresponding to the stress presented in this study. Between methamodophos and copper, there happened the significant joint-toxic actions when they were used in combination on DHA and carbon source substrate utilizing fingerprint patterns of soil bacterial communities. The DHA of soil under the combined stresses was lower than that of the control and that under the single factors, and the BIOLOG(GN) substrate utilizing patterns of soil treated by combinations were distinctively differentiated from the control and their corresponding single factors. From all of above, the methamidophos, copper, especially their combinations had the clearly potential ecotoxicological risks to influence the natural soil microbial ecological system by changing the structure, richness, and the functional characteristics of microbial community.

Bacteria↗

PubMed2005

Correlations between the ages of Alnus host species and the genetic diversity of associated endosymbiotic Frankia strains from nodules.

Nodule samples were collected from four alder species: Alnus nepalensis, A. sibirica, A. tinctoria and A. mandshurica growing in different environments on Gaoligong Mountains, Yunnan Province of Southwest China and on Changbai Mountains, Jilin Province of Northeast China. PCR-RFLP analysis of the IGS between nifD and nifK genes was directly applied to uncultured Frankia strains in the nodules. A total of 21 restriction patterns were obtained. The Frankia population in the nodules of A. nepalensis had the highest genetic diversity among all four Frankia populations; by contrast, the population in the nodules of A. mandshurica had the lowest degree of divergence; the ones in the nodules of A. sibirica and A. tinctoria were intermediate. A dendrogram, which was constructed based on the genetic distance between the restriction patterns, indicated that Frankia strains from A. sibirica and A. tinctoria had a close genetic relationship. Frankia strains from A. nepalensis might be the ancestor of Frankia strains infecting other Alnus species. From these results and the inference of the ages of Alnus host species, it is deduced that there was a co-evolution between Alnus and its microsymbiont Frankia in China.

Alnus↗

PubMed2005

[Effects of acetochlor and methamidophos on culturable fungal population and community structure in black soil].

By the methods of CFU and rDNA-PCR-DGGE, this paper studied the dynamic changes of culturable fungal populations, community structure, and population richness in black soil under stress of acetochlor and methamidophos. The results showed that the growth of fungi was promoted under lower concentration acetochlor (50 mg x kg(-1)), but long-standing inhibited under its higher concentration (250 mg x kg(-1)). 250 mg kg(-1) methamidophos promoted the growth of culturable fungi intensively during 8-week period, resulting in 10 times increase in CFU of fungi than the control, while low concentration methamidophos (50 mg x kg(-1)) had no evident effect. The richness of culturable fungi in soil treated by medium and high concentration acetochlor was decreased irreversibly. Cluster analysis of fungal rDNA-PCR-DGGE fingerprints profile showed that acetochlor and methamidophos could change the culturable fungal community structure diversely, and the effect of methomidophos was more obvious.

Fungi↗

PubMed2005

[Impacts of petroleum-containing wastewater irrigation on microbial population and enzyme activities in paddy soil of Shenfu irrigation area].

The study showed that the upper reaches of main petroleum-containing wastewater irrigation channels had the highest accumulation and distribution of total petroleum hydrocarbon (TPH) (5 213.37 mg x kg(-1) dry soil),and the CFU of soil bacteria and fungi was increased with increasing soil TPH concentration, the correlation coefficient being 0.928 (P < 0.001) and 0.772 (P < 0.05), respectively. The activities of soil dehydrogenase, catalase and polyphenoloxidase had a significantly positive correlation with soil TPH concentration, their correlation coefficient being 0.974 (P < 0.001), 0.957 (P < 0.001) and 0.886 (P < 0.001), respectively, while soil urease activity showed a significantly negative correlation (P = 0.002), which could be used as the most sensitive indicator of petroleum contamination. The substrate-induced respiration (SIR) of polluted soil was significantly correlated with soil TPH concentration (P < 0.001), dehydrogenase activity (P < 0.001), and heterotrophic bacterial CFU (P = 0.006).

Hydrocarbons↗

PubMed2004

Identification of a novel alternative splicing form of human netrin-4 and analyzing the expression patterns in adult rat brain.

Netrins are a family of secreted proteins that function as tropic cues directing axon growth and cell migration during neural development. Beta-netrin or netrin-4 (NTN4), the fourth member of this family, was previously reported by Koch (M. Koch, J.R. Murrell, D.D. Hunter, P.F. Olson, W. Jin, D.R. Keene, W.J. Brunken, R.E. Burgeson. A novel member of the netrin family, beta-netrin, shares homology with the beta chain of laminin: identification, expression, and functional characterization. J. Cell Biol. 151 (2000) 221-234) and Yin (Y. Yin, J.R. Sanes, J.H. Miner, Identification and expression of mouse netrin-4. Mech. Dev. 96 (2000) 115-119), respectively. However, whether there is another isoform of netrin-4 and the expression patterns have not been fully determined. Here we report the cloning of a novel isoform of human netrin-4 using rapid amplification of complementary DNA (cDNA) ends (RACE) technique and analysis on the netrin-4 mRNA expression in adult rat brain using in situ hybridization. The new isoform lacks the signal peptide region and might represent a truncated form at the Laminin-N terminal domain of human netrin-4. Examination of the expression pattern of netrin-4 mRNA in adult rat brain revealed that the netrin-4 mRNA was widely expressed in many regions of the brain. High levels of netrin-4 mRNA was found in the pyramidal cell layer of the cerebral cortex, prepiriform cortex, amygdaloid nuclei, pyramidal layer of hippocampus, Purkinje's cells, medial cerebellar nucleus and interposed cerebellar nucleus, medial nucleus of the trapezoid body and mitral cell layer of the olfactory bulb. Moderate signals were present in frontal cortex, several thalamic and hypothalamic nuclei. The widespread expression of netrin-4 in adult rat brain indicates that netrin-4 is not only important for axon guidance during embryonic development, but also critical to neuronal plasticity in adult stage.

Alternative Splicing↗

PubMed2004

Characterization of Ceap-11 and Ceap-16, two novel splicing-variant-proteins, associated with centrosome, microtubule aggregation and cell proliferation.

A novel human gene, encoding two polypeptide-isoforms, has been identified from human fetal liver cDNA library. These two alternatively spliced polypeptide-variants are associated with centrosomes, and are designated Ceap-11 and Ceap-16, respectively, according to the acronym Ceap for centrosomal-associated protein and the approximate relative molecular mass. The high degree of sequence similarity between Ceap proteins of divergent species indicates that the Ceap homologous genes are significantly conserved in evolution and constitute a new gene family without any functional information until now. Human Ceap gene is mapped on 10q24.2. These two Ceap cDNA isoforms are generated by RNA alternative splicing on the 5' terminus of the Ceap gene, and are composed of four and five exons, respectively. Ceap-11 and Ceap-16 are co-immunoprecipitated and co-located with gamma-tubulin; ectopic overexpression of these two proteins in NIH3T3 cells induces microtubule aggregation and cell proliferation; the protein level of Ceap in certain tumors is significantly higher than that in corresponding normal tissues. Taken together, our data provide the first evidence for the function of Ceap-11 and Ceap-16, the two novel human proteins, namely, association with centrosome, microtubule aggregation and cell proliferation.

Alternative Splicing↗

PubMed2004

Crystallization and preliminary X-ray studies of methyl parathion hydrolase from Pseudomonas sp. WBC-3.

Methyl parathion hydrolase (MPH) from Pseudomonas sp. WBC-3, an enzyme that catalyzes the degradation of methyl parathion (O,O-dimethyl O-p-nitrophenyl phosphorothioate; MP), has been purified and crystallized by the hanging-drop vapour-diffusion method. The crystals were grown at 291 K using a precipitant solution consisting of 30% PEG 400, 0.1 M sodium acetate pH 4.6, 0.1 M CdCl(2). MPH is a zinc-containing enzyme judged by inductively coupled plasma mass-spectrometric (ICP-MS) analysis. Multiple-wavelength anomalous dispersive X-ray data were collected at 2.5 A resolution from a single crystal on beamline 41XU at SPring-8. The crystal belongs to space group P4(3)2(1)2, with unit-cell parameters a = 84.94, b = 84.94, c = 200.38 A, alpha = beta = gamma = 90 degrees. The asymmetric unit contains two molecules and has a solvent content of approximately 52%. Crystal structure determination is in progress.

Crystallization↗

PubMed2004

Molecular cloning of novel cellulase genes cel9A and cel12A from Bacillus licheniformis GXN151 and synergism of their encoded polypeptides.

A thermophilic bacterial strain GXN151 which could degrade Avicel efficiently was isolated and identified as Bacillus licheniformis. A genomic library of GXN151 was constructed and two novel endoglucanase genes designated cel9A and cel12A were isolated by screening the library on carboxylmethyl cellulase indicator plates. The analysis of amino acid sequences deduced from the genes indicated that Cel9A consisted of a catalytic domain belonging to glycosyl hydrolase family 9, a linker domain, and a carbohydrate binding module family 3 from N-terminal to C-terminal; Cel12A had only one catalytic domain belonging to glycosyl hydrolase family 12. The combinations of Cel9A and Cel12A produced by the recombinant E. coli exhibited synergistic action against substrates of carboxylmethyl cellulose as well as Avicel.

Bacillus↗

PubMed2004

[Diversity of Frankia in nodules of Alnus nepalensis at Gaoligong Mountains revealed by IGS, PCR-RFLP analysis].

30 nodule samples were used to assess the diversity of Frankia strains symbiotically associated with Alnus nepalensis naturally occurring at the Gaoligong Mountains in Yunnan Province, China. DNA was extracted directly from nodules, and its two target DNA regions that encode nifD-nifK intergenic spacer (IGS) and 16S-23S rDNA IGS was studied by PCR-RFLP. The PCR fragments yielded by the nifD-nifK IGS were noticeably different in size, and when they were digested by Hae III and Afa I, 15 nif-type Frankia strains could be detected, the PCR-RFLP result of this region also could show that more than one genotype Frankia strains could form symbiosis with individual plants at the same time. The 16S-23S rDNA IGS had similar PCR fragments, but still identified 15 rrn-type strains after digested by Hae III and Afa I. 20 genotype strains could be found only when combined the PCR-RFLPs of two target regions.

Alnus↗

PubMed2004

[Research advances in soil fungal diversity and molecular ecology].

Fungi are a kind of important soil microorganisms that participate in the decomposition of organic materials and supply nutrients to the plant through symbiosis. But, they can also reduce the output of food due to the existence of pathogenic fungi. Soil fungal diversity plays a fundamentally unique role in maintaining the balance of ecosystem and in supplying large amount of undeveloped resources for the people. In this paper, soil fungal diversity was expatiated from the viewpoints of species diversity, habitant diversity and functional diversity, and furthermore, the research advances in the molecular ecology of soil fungal diversity were reviewed from the aspects of the fungal diversity of farmland, woodland, pasture, extreme environment, and other complex environments. The affecting factors of soil fungal diversity were discussed, and the development trend of the study on soil fungal diversity was also approached.

Basidiomycota↗

PubMed2003

A real-time and dynamic biological information retrieval and analysis system (BIRAS).

The aim of this study is to design a biological information retrieval and analysis system (BIRAS) based on the Internet. Using the specific network protocol, BIRAS system could send and receive information from the Entrez search and retrieval system maintained by National Center for Biotechnology Information (NCBI) in USA. The literatures, nucleotide sequence, protein sequences, and other resources according to the user-defined term could then be retrieved and sent to the user by pop up message or by E-mail informing automatically using BIRAS system. All the information retrieving and analyzing processes are done in real-time. As a robust system for intelligently and dynamically retrieving and analyzing on the user-defined information, it is believed that BIRAS would be extensively used to retrieve specific information from large amount of biological databases in now days. The program is available on request from the corresponding author.

Animals↗

PubMed2003

[Introduction and progress of molecular microbial ecology].

Molecular microbial ecology is an interdisciplinary field of molecular biological techniques and microbial ecology, which deals with microbial population, diversity, function, and relationships between microorganisms and biotic and abotic environments in microbial ecosystem. All the progress in molecular microbial ecology, especially in microbial diversity, phylogeny and communities of some microoganisms, indicate the renovation in traditional microbial ecology by the introduction of molecular techniques and strategies. This article reviewed the ideation, development, key domains, main methods and the future hot fields in molecular microbial ecology.

Ecology↗

PubMed2003

[Effect of natural stress on genetic diversity of Frankia in Alnus nodules].

The genetic diversity of Frankia in the nodules of Alnus nepalensis growing in different habitats of Jizu and Wuliang Mountains in Yunnan Province was studied by rep-PCR technique. The results indicated that the Frankia had an abundant genetic diversity, which was varied with different zones, altitudes and slopes. More genotypes of Alnus-infective Frankia were found at Jizu than at Wuliang Mountain. At the bottom of Jizu Mountain (2,300 m), the Shannon-Weiner index was 0.90, and increased with raising altitude, up to 1.33 at the top (2,700 m). The genetic diversity of Frankia was more abundant along the southern slope than the northern slope. It was concluded that the diversity index was positively related to natural stresses which were one of the important factors producing and maintaining the genetic diversity of Frankia.

Alnus↗