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Xiaojun Zhang

Publications and source records attributed to Xiaojun Zhang.

15 recordsLinked to original sources
PubMed2006

Cloning of environmental genomic fragments as physical markers for monitoring microbial populations in coking wastewater treatment system.

The association between community functional shift and dynamics of genomic DNA composition can be used to identify functionally relevant populations as indicator organisms for systems monitoring. In this work, fingerprinting-based community DNA hybridization was used to monitor community structural dynamics and identify genomic fragments whose abundance shifts were concomitant to changes in COD removal capacity in a reactor. A laboratory-scale anaerobic-anoxic-oxic fixed biofilm system treating coking wastewater was operated with (LR mode) or without effluent recirculation (LNR mode). The contribution to total chemical oxygen demand (COD) removal by the anoxic reactor increased from 4% in LNR mode to 26% in LR mode. Long primer RAPD (randomly amplified polymorphic DNA) community fingerprints of the anoxic reactor also changed most significantly from the one similar to the anaerobic reactor to one similar to the oxic reactor. DNA hybridization revealed one signature band of 2.1 kb shared by the anoxic and oxic reactors in LR, but not LNR mode. Clone library profiling of this band resulted in one predominant 2.1-kb genomic fragment (B3) with no homologous sequences in GenBank. Real-time polymerase chain reaction indicated that copy numbers of B3 in the anoxic reactor under LR mode were 69 times higher than that under LNR mode, concomitant to a significant increase in COD removal capacity in this reactor. The different patterns of distribution of B3 in the laboratory system and a comparable malfunctioning industrial system demonstrated the potential of this genomic fragment as physical markers in systems monitoring. In addition, this genomic fragment may allow sequence-guided isolation of the host microbe.

Bacteria↗
PubMed2006

Association between presenilin 1 intronic polymorphism and late onset Alzheimer's disease in the North Chinese population.

The association between presenilin 1 intronic polymorphism (rs165932) and late onset Alzheimer's disease (LOAD) has been a matter of controversy. Within China, varied results have been reported. Therefore, we collected a large sample from the North Chinese population to test the association of the PS1 polymorphism with LOAD. AD patients (467 total, mean age=75.3+/-7.3, age at onset=70.2+/-5.1) and age-matched normal elderly controls (480 total) were recruited. Genotypes of PS1 and apolipoprotein E (APOE) were determined by PCR and RFLP. The results showed that there were significant differences in the distributions of both alleles (chi(2)=45.305, P<10(-5)) and genotypes (chi(2)=53.055, P<10(-5)) of PS1 gene between the AD and control groups. The APOE epsilon4 allele was more prevalent in patients than in controls (chi(2)=46.389, P<10(-5)). It was significantly different when PS1 alleles and genotypes were compared between AD and controls with APOE epsilon4 negative. However, no significance was found when PS1 alleles or genotypes were compared between AD and controls with APOE epsilon4 positive. Furthermore, with PS1 2/2 genotype as a reference, the odds ratios (ORs) of LOAD with PS1 1/2, 1/1+1/2 and 1/1 genotypes gradually increased allele 1 copy number, suggesting that allele 1 is a crucial risk for LOAD. In summary, we found an association between presenilin 1 intronic polymorphism and LOAD, but no influence of APOE epsilon4 on the distribution of the PS1 intronic polymorphism. In addition, the larger sample size raises the possibility that ethnic and regional differences in China may explain the differences in reported results.

Aged↗
PubMed2006

Discovery of the genes in response to white spot syndrome virus (WSSV) infection in Fenneropenaeus chinensis through cDNA microarray.

We used microarray technology to study differentially expressed genes in white spot syndrome virus (WSSV)-infected shrimp. A total of 3136 cDNA targets, including 1578 unique genes from a cephalothorax cDNA library and 1536 cDNA clones from reverse and forward suppression subtractive hybridization (SSH) libraries of Fenneropenaeus chinensis, plus 14 negative and 8 blank control clones, were spotted onto a 18 x 18 mm area of NH(2)-modified glass slides. Gene expression patterns in the cephalothorax of shrimp at 6 h after WSSV injection and moribund shrimp naturally infected by WSSV were analyzed. A total of 105 elements on the arrays showed a similar regulation pattern in artificially infected shrimp and naturally infected moribund shrimp; parts of the results were confirmed by semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR). The up-regulated expression of immune-related genes, including heat shock proteins (HSP70 and HSP90), trehalose-phosphate synthase (TPS), ubiquitin C, and so forth, were observed when shrimp were challenged with WSSV. Genes including myosin LC2, ATP synthase A chain, and arginine kinase were found to be down-regulated after WSSV infection. The expression of housekeeping genes such as actin, elongation factor, and tubulin is not stable, and so these genes are not suitable as internal standards for semiquantitative RT-PCR when shrimp are challenged by WSSV. As a substitute, we found that triosephosphate isomerase (TPI) was an ideal candidate of interstandards in this situation.

Animals↗
PubMed2006

Cloning, expression and identification of ferritin from Chinese shrimp, Fenneropenaeus chinensis.

Ferritin, the iron storage protein, plays a key role in iron metabolism. A cDNA encoding ferritin (FcFer) was cloned from hepatopancreas of Chinese shrimp, Fenneropenaeus chinensis. The predicted protein contains 170 amino acid residues with a predicted molecular weight (MW) about 19, 422.89 Da and theoretical isoelectric point (PI) of 4.73. Amino acid alignment of FcFer revealed 97% homology with Litopenaeus vannamei ferritin. Results of the RT-PCR showed that the expression of FcFer mRNA was up-regulated after shrimp was challenged with either white spot syndrome virus (WSSV) or heavy metal ions (Zn2+ and Cu2+) in the laboratory. A fusion protein containing FcFer was produced and the purified recombinant protein exhibited similar function of iron uptake in vitro. The result of in-gel digestion and identification using LC-ESI-MS showed that two peptide fragments (-DDVALPGFAK- and -LLEDEYLEEQVDSIKK-) of the recombinant protein were identical to the corresponding sequence of L. vannamei ferritin. The recombinant FcFer protein will be proved useful for study on the structure and function of ferritin in F. chinensis.

Amino Acid Sequence↗
PubMed2006

Pediatric homonymous hemianopia.

INTRODUCTION: Homonymous hemianopia is a disabling condition caused by numerous lesions affecting the retrochiasmal visual pathways. Little is known about homonymous hemianopia in childhood. METHODS: All patients seen in the Neuro-Ophthalmology Unit at Emory University with homonymous hemianopia (confirmed by Goldmann, Humphrey, or confrontation visual fields) between 1989 and 2004 were included. Demographic characteristics, clinical features, and evolution of the visual field defects were compared between the pediatric group (18 years of age or younger) and the adult group (older than 18 years). RESULTS: Among 852 patients with homonymous hemianopia, there were 81 children (86 homonymous hemianopias) and 771 adults (818 homonymous hemianopias). Formal visual field testing was obtained in 93% of pediatric cases and 96% of adults; a majority of patients in both groups were evaluated with Goldmann visual field testing. Demographic and visual field characteristics were similar in both groups. Significant differences were noted for the causative lesions and their location. Traumatic brain injury (34%) and tumor (27%) were the most common causes of homonymous hemianopia in the pediatric group, whereas infarction (63%), traumatic brain injury (12%), and hemorrhage (11%) were the most common causes in the adult group. Most lesions involved the optic radiations (37%), followed by the occipital lobes (26%), in the pediatric group, whereas occipital lobes (47%), followed by optic radiations (32%), were most commonly involved in adults. Approximately one third of the pediatric patients were seen in follow-up, and one third of these homonymous hemianopias spontaneously improved over the course of time. Of the 16 pediatric homonymous hemianopias evaluated within 1 month of onset of the cerebral disorder, 8 (50%) improved. CONCLUSION: Trauma and tumors are the most common cause of homonymous hemianopia in childhood. Although spontaneous improvement can be expected in approximately one third to one half of patients within the first few months, the recognition of homonymous hemianopia frequently is delayed in this population.

Adolescent↗
PubMed2006

Homonymous hemianopia in stroke.

BACKGROUND: Previous reports have suggested that most cases of homonymous hemianopia (HH) are caused by occipital stroke. However, these reports have not always been supported by brain imaging. METHODS: We reviewed the medical records of all patients seen in our unit between 1989 and 2004 who had HH documented by formal perimetry or confrontation visual fields and had undergone brain imaging. HHs were divided into those caused by stroke and by non-stroke conditions. The clinical and visual field characteristics were compared in the two groups. RESULTS: Among 850 patients with 902 HHs, 629 (69.7%) resulted from stroke, of which 531 (84.4%) were from infarction and 98 (15.6%) from primary intraparenchymal hemorrhage. Non-stroke causes included head trauma (123), brain tumor (102), neurosurgical procedures (22), multiple sclerosis (13), and miscellaneous conditions (13). Occipital lesions most commonly resulted from stroke. The configuration of the HH did not predict where in the retrochiasmal visual pathway the responsible lesion lay. CONCLUSIONS: Ischemic stroke causes most HHs from lesions in the occipital lobe that generally do not produce other neurologic manifestations. The configuration of the HH does not predict the location of the lesion within the retrochiasmal visual pathway.

Adolescent↗
PubMed2006

Thauera and Azoarcus as functionally important genera in a denitrifying quinoline-removal bioreactor as revealed by microbial community structure comparison.

Structural shifts associated with functional dynamics in a bacterial community may provide clues for identifying the most valuable members in an ecosystem. A laboratory-scale denitrifying reactor was adapted from use of non-efficient seeding sludge and was utilized to degrade quinoline and remove the chemical oxygen demand. Stable removal efficiencies were achieved after an adaptation period of six weeks. Both denaturing gradient gel electrophoresis profiling of the 16S rRNA gene V3 region and comparison of the 16S rRNA gene sequence clone libraries (LIBSHUFF analysis) demonstrated that microbial communities in the denitrifying reactor and seeding sludge were significantly distinct. The percentage of the clones affiliated with the genera Thauera and Azoarcus was 74% in the denitrifying reactor and 4% in the seeding sludge. Real-time quantitative PCR also indicated that species of the genera Thauera and Azoarcus increased in abundance by about one order of magnitude during the period of adaptation. The greater abundance of Thauera and Azoarcus in association with higher efficiency after adaptation suggested that these phylotypes might play an important role for quinoline and chemical oxygen demand removal under denitrifying conditions.

Azoarcus↗
PubMed2006

Involvement of interaction between Fractalkine and CX3CR1 in cytotoxicity of natural killer cells against tumor cells.

Many chemokine receptors are typically found on natural killer cells, including CX3CR1, the receptor for the chemokine fractalkine (FKN). This study explored whether interaction between CX3CR1 and FKN is relevant for NK cell functions in cytotoxicity against tumors. FKN expression was examined by polymerase chain reaction and CX3CR1 expression in NK cells was analyzed by flow cytometry. NK cell cytotoxicity was examined by 4-h 51Cr-release assay. FKN was expressed in a variety of tumor cell lines such as K562 cells, an NK-sensitive cell line. Approximately 90% of peripheral blood NK cells and almost all of the NK cell line, NK-92 cells, expressed CX3CR1. Anti-CX3CR1 antibody strongly neutralized the cytotoxicity of NK cells against K562 cells, and pretreatment of NK cells with recombinant soluble FKN improved the cytolytic function on tumor cells. This study demonstrates that an interaction between CX3CR1 on NK cells and FKN on tumor cells is involved in the natural cytotoxicity of NK cells against tumors.

CX3C Chemokine Receptor 1↗
PubMed2005

Antisense-induced blockade of GATA-3 expression could inhibit Th2 excursion of tumor cells in vitro and in vivo.

Previous studies have shown that tumor cells predominantly express Th2 type cytokines and transcription factors. GATA-3, as a Th2-specific transcription factor, plays a central role in positive-regulating Th2 development. So whether the expression of GATA-3 in tumor cells has any effect on tumor development is a question of interest. In the present study, we inhibited the expression of GATA-3 in tumor cells through antisense RNA blockade technique, and observed its effects on tumor in vitro and in vivo. Our results showed that antisense GATA-3 treatment could inhibit the expression of TNF-alpha and Th2 cytokines in tumor cells, and antisense-induced blockade of GATA-3 could also depress tumor growth in tumor-bearing mice. We suggest that the ratio of T-bet/GATA-3 can be evaluated as a more important marker of the status of Th1/Th2 type. And our results might provide some evidence about the molecular regulatory mechanisms in tumor cell development.

Animals↗
PubMed2004

What is the maximum duration to perform the hemorheological measurement for the human and mammals.

The hemorheological performance of mammals and human will change with the time after the blood is withdraw from the subject. The whole blood apparent viscosity, erythrocyte deformability and aggregation of some mammals and human were measured. Our results showed that the hemorheological characteristics of mice, rats, guinea pigs, dogs and human began to change respectively after the threshold time of 0.5, 1, 3, 7, 12 h when the blood were stored in vitro. Moreover there exist a relationship: t=3.18W(0.32) between the threshold time (t) and the animal weight (W) and the related coefficient is 0.992.

Adult↗
PubMed2003

Gonad development characteristics and sex ratio in triploid Chinese shrimp ( Fenneropenaeus chinensis).

This paper details for the first time the gonad development characteristics and sex ratio of triploid shrimp ( Fenneropenaeus chinensis). In triploid shrimp the development of gonad is apparently impaired, especially in females. In the ovary of triploids, germ cells mainly remain at oogonia stage during September through December. From January to February of the next year, partial primary oocytes developed in the ovary lobes. Spermatocytes and spermatids could be observed in the testes of triploids, and a few sperm were observed in the vas deferens and spermatophores. The morphology of sperms in triploid shrimp was abnormal. Flow cytometry was used to detect the ploidy of sperm in the vas deferens. The data showed that triploidy could affect the sex ratio in Chinese shrimp. The female-to-male ratio in triploids of about 4:1 will favor triploid shrimp aquaculture.

Animals↗
PubMed2002

Structure of the inhibitory region of troponin by site directed spin labeling electron paramagnetic resonance.

Site-directed spin labeling EPR (SDSL-EPR) was used to determine the structure of the inhibitory region of TnI in the intact cardiac troponin ternary complex. Maeda and collaborators have modeled the inhibitory region of TnI (skeletal 96-112: the structural motif that communicates the Ca(2+) signal to actin) as a kinked alpha-helix [Vassylyev, D., Takeda, S., Wakatsuki, S., Maeda, K. & Maeda, Y. (1998) Proc. Natl. Acad. Sci. USA 95, 4847-4852), whereas Trewhella and collaborators have proposed the same region to be a flexible beta-hairpin [Tung, C. S., Wall, M. E., Gallagher, S. C. & Trewhella, J. (2000) Protein Sci. 9, 1312-1326]. To distinguish between the two models, residues 129-145 of cardiac TnI were mutated sequentially to cysteines and labeled with the extrinsic spin probe, MTSSL. Sequence-dependent solvent accessibility was measured as a change in power saturation of the spin probe in the presence of the relaxation agent. In the ternary complex, the 129-137 region followed a pattern characteristic of a regular 3.6 residues/turn alpha-helix. The following region, residues 138-145, showed no regular pattern in solvent accessibility. Measurements of 4 intradomain distances within the inhibitory sequence, using dipolar EPR, were consistent with an alpha-helical structure. The difference in side-chain mobility between the ternary (C.I.T) and binary (C.I) complexes revealed a region of interaction of TnT located at the N-terminal end of the inhibitory sequence, residues 130-135. The above findings for the troponin complex in solution do not support either of the computational models of the binary complex; however, they are in very good agreement with a preliminary report of the x-ray structure of the cardiac ternary complex [Takeda, S. Yamashita, A., Maeda, K. & Maeda, Y. (2002) Biophys. J. 82, 832].

Animals↗
PubMed2002

[Relation between coronary artery disease and polymorphism of angiotensin converting enzyme gene].

This study was aimed to determine the relationship between coronary artery disease(CAD) and insertion/deletion(I/D) polymorphism of the angiotensin coverting enzyme(ACE) gene. The ACE genotypes of 105 patients with CAD (50 of them were accompanied by essential hypertension (EH)) and 102 healthy people were detected by polymerase chain reaction. The results showed that in terms of ACE genotypes, no significant difference was noted between CAD group and control group, nor was it observed between CAD group and CAD accompanied by EH group, and nor was it seen between CAD/CAD accompanied by EH group and control group. These findings suggest that there is no relationship between the polymorphism of ACE gene and CAD (including those accompanied by EH).

Adult↗
PubMed2002

Inhibitors of hepatitis C--a review of the recent patent literature.

A review of the patent literature for inhibitors of hepatitis C virus (HCV) is presented for the period of January 2001 to December 2001. This review focuses on inhibitors of virally encoded enzymes/proteins, especially HCV NS3 serine protease and NS5B RNA-dependent RNA polymerase (RDRP), both of which have emerged as primary anti-HCV targets as a result of detailed understanding of their biological functions and the high quality structural information available. A number of potent small molecule inhibitors for these enzymes have been disclosed during this period of time. Inhibitors of other virally encoded enzymes have also been reported, but in lower numbers. With recent advances in obtaining a stable HCV cell-based assay to facilitate screening and selection of inhibitors, it is highly likely that effective small molecule antiviral therapies for HCV infection should soon emerge.

Journal Article↗