Biomedical subjects

Xu Jia

Publications and source records attributed to Xu Jia.

11 recordsLinked to original sources

PubMed2005

[Wheat transformation by electroporation with ring electrode].

Electroporation has been used effectively to deliver DNA into the tissue of intact wheat immature embryos. The physical parameters of electroporation were 770 V/cm field strength, 800 microF capacitor and 100 microg/mL of plasmid DNA, containing bar and GUS gene. The electroporation was carried out by a portable and permanent ring electrode that can be fitted into the wells of 24-well plates. The samples were pulsed three times. Integration of the introduced genes into the genome of transgenic wheat plants was shown by PCR and Southern blot analysis. Transformation frequency was 7.5%, that is higher than that of the 4.2% frequency by microprojectile bombardment.

DNA, Plant↗

PubMed2005

Studies on wheat mutants induced by nitrogen ion beam implantation.

As a new resource of mutagens,low-energy ion beam implantation is characterized as limited physiological damages,wide mutation spectrum, and high mutation frequency in comparison with the mutations from other inducing methods. We treated a wheat doubled haploid line Yi4212 with this technique by nitrogen ion and established a mutant population with 60 lines in our lab. The mutant lines were systematically investigated about their -developmental periods,agronomical performances, gliadin contents and microsatellite variations in M4 generation. The results revealed that in addition to extensive changes of the developmental, agronomical and economical traits of the mutants,the moblities in acid-PAGE of 7 omega-gliadin subunits were also showed changes as some gliadins lacked and novel gliadins obtained. Deletion, expansion and contraction of SSR amplification products occured frequently in 25 SSR loci in the mutants. Combined with our results and other reports,the application prospects of those wheat mutants and the mutation mechanism by ion beam implantation are discussed.

Chromosomes, Plant↗

PubMed2004

Dynamic changes in the expression of matrix metalloproteinases and their inhibitors, TIMPs, during hepatic fibrosis induced by alcohol in rats.

AIM: To determine the dynamic changes in the expression of matrix metalloproteinases (MMPs) and the endogenous tissue inhibitors of MMPs inhibitors (TIMPs) during hepatic fibrosis induced by alcohol. METHODS: Male Sprague-Dawley rats were randomly divided into normal, 4 d, 2 wk, 4 wk, 9 wk and 11 wk groups, and the model rats were fed with a mixture of alcohol by gastric infusion at the designed time, respectively, then decollated and their livers were harvested for the examination of MMP-2, MMP-3, MMP-9, MMP-13, TIMP-1 and TIMP-2 by immunohistochemistry, zymograghy and Western blotting, respectively. RESULTS: Normal rats had moderate expression of MMP-2, which was decreased in the model rats except in the 11 wk group, where MMP-2 expression slightly increased. MMP-3 had the similar changing pattern to MMP-2 despite weaker expression. MMP-9 expression decreased in the 4 d and 2 wk groups, rose in the 4 wk group, decreased again in the 9 wk group and returned to normal levels in the 11 wk group. MMP-13 expression decreased in the 4 d and 2 wk groups, and returned to normal levels in the 4 wk, 9 wk and 11 wk groups. TIMP-1 expression decreased in the 4 d and 2 wk groups, but sharply increased in the 4 wk group and sustained at a high level even after modeling was stopped for 2 wk. In normal rats TIMP-2 expression was strong. However, it decreased as soon as modeling began, and then gradually rose, but remained to a level lower than that in normal rats even after modeling was stopped for 2 wk. CONCLUSION: MMP-2 may not always expresses at a high level during hepatic fibrosis. MMP-13 and MMP-3 are acutely affected by TIMP-1. In this model TIMP-1 is the most powerful factor imposed on capillarization and peri-sinusoidal fibrosis. TIMP-2 is the most effective regulator on the metabolism of type IV collagen located in the basement of sinus.

Animals↗

PubMed2004

Dynamic changes of capillarization and peri-sinusoid fibrosis in alcoholic liver diseases.

AIM: To investigate the dynamic changes of capillarization and peri-sinusoid fibrosis in an alcoholic liver disease model induced by a new method. METHODS: Male SD rats were randomly divided into 6 groups, namely normal, 4 d, 2 w, 4 w, 9 w and 11 w groups. The animals were fed with a mixture of alcohol for designated days and then decollated, and their livers were harvested to examine the pathological changes of hepatocytes, hepatic stellate cells, sinusoidal endothelial cells, sinusoid, peri-sinusoid. The generation of three kinds of extra cellular matrix was also observed. RESULTS: The injury of hepatocytes became severer as modeling going on. Under electronic microscope, fatty vesicles and swollen mitochondria in hepatocytes, activated hepatic stellate cells with fibrils could been seen near or around it. Fenestrae of sinusoidal endothelial cells were decreased or disappeared, sinusoidal basement was formed. Under light microscopy typical peri-sinusoid fibrosis, gridding-like fibrosis, broaden portal areas, hepatocyte's fatty and balloon denaturation, iron sediment, dot necrosis, congregated lymphatic cells and leukocytes were observed. Type I collagen showed an increasing trend as modeling going on, slightly recovered when modeling stopped for 2 weeks. Meanwhile, type IV collagen decreased rapidly when modeling began and recovered after modeling stopped for 2 weeks. Laminin increased as soon as modeling began and did not recover when modeling stopped for 2 weeks. CONCLUSION: The pathological changes of the model were similar to that of human ALD, but mild in degree. It had typical peri-sinusoid fibrosis, however, capillarization seemed to be instable. It may be related with the reduction of type IV collagen in the basement of sinusoid during modeling.

Animals↗

PubMed2004

The HopPtoF locus of Pseudomonas syringae pv. tomato DC3000 encodes a type III chaperone and a cognate effector.

Type III secretion systems are highly conserved among gram-negative plant and animal pathogenic bacteria. Through the type III secretion system, bacteria inject a number of virulence proteins into the host cells. Analysis of the whole genome sequence of Pseudomonas syringae pv. tomato DC3000 strain identified a locus, named HopPtoF, that is homologous to the avirulence gene locus avrPphF in P. syringae pv. phaseolicola. The HopPtoF locus harbors two genes, ShcF(Pto) and HopF(Pto), that are preceded by a single hrp box promoter. We present evidence here to show that ShcF(Pto) and HopF(Pto) encode a type III chaperone and a cognate effector, respectively. ShcF(Pto) interacts with and stabilizes the HopF(Pto) protein in the bacterial cell. Translation of HopF(Pto) starts at a rare initiation codon ATA that limits the synthesis of the HopF(Pto) protein to a low level in bacterial cells.

Amino Acid Sequence↗

PubMed2004

Expression pattern of UidA gene under the control of rice glutelin GluA-2 gene upstream sequence in transgenic rice endosperm.

In order to study the expression pattern of rice glutelin endosperm specific promoter in Chinese cultivar Zhonghua 8 (Oryza sativa L. subsp japonica), UidA gene was fused with rice glutelin GluA-2 gene 5' upstream sequence 2.3 kb and 750 bp upstream respectively and transferred into rice by Agrobacterium mediated transformation. Southern blot indicated that UidA gene was integrated into the genome of transgenic plants as single copy. Northern blot demonstrated that the expression of UidA gene and endogenous GluA-2 gene reached their highest level at 13-15 days and 11-13 days after pollination respectively, and then declined. Histochemical staining of immature transgenic rice seeds showed UidA gene was specifically expressed in endosperm and the highest level GUS expression was observed in aleurone layer. Quantitative analysis of GUS activity showed seeds GUS activity of that 2.3 kb transgenic plant was about two to three folds of those of 750 bp transgenic plant. Sequence analysis suggested that the G-box located in the -2,170 bp (from transcription start site) may be a quantitative cis-element.

Blotting, Southern↗

PubMed2004

[Saline tolerance white clover transformed with the betaine aldehyde dehyrogenase gene by Agrobacterium tumefaciens].

The white clover has been transformed with the Betaine Aldehyde Dehydrogenase (BADH) gene cloned from Atriplex hortensis by Agrobacterium tumefaciens. The relative electronic conductivity of the transgenic plants under 1% NaCl stress for 48 hours was about 20%, less than the control plant's relative electronic conductivity (more than 40%), these showed the cell membrane of the transgenic plants has been less injured than control plants under salt stress. The other experience showed that the transgenic plant could grow well in water culture included 0.5% NaCl for more than two weeks, but the control plants could not.

Agrobacterium tumefaciens↗

PubMed2004

[Obtainment of transgenic wheat with the insecticidal lectin from snowdrop (Galanthus nivalis agglutinin; GNA) gene and analysis of resistance to aphid].

Snowdrop lectin (Galanthus nivalis agglutinin; GNA) is toxic to sap sucking injurious insects of Homopteran. A new gna gene has been transferred into common spring wheat Zhong60634 and winter wheat Yumai66 with high yield by using the biolistic transformation method. Transgenic wheat plants have been obtained in both of the two varieties. Two transgenic plants (T0) have been obtained from the bombarded 535 immature embryos of Zhong60634. Bioassay results show that the development of aphid could be slowed down and the survival rate of young aphid could be reduced by gna gene. Seventeen transgenic plants (T0) were obtained from the bombarded 4636 immature embryos of Yumai66. Twenty plantlets with good resistance to Rhopalosiphum padi and Macrosiphum avenae, which are mainly aphid in north wheat area, were identified from the transgenic plants of T1 generation that came from 8 T0 transgenic plants with good resistance to aphid. The anti-aphid bioassay shows that resistance to the different grain aphid is not the same in transgenic wheat plants. To Rhopalosiphum padi, the rate of survival aphid 8 days after exposing transgenic plants to aphids is significantly lower than that of nontransgenic plants. To Macrosiphum avenae, growth speed of aphids is slowed down but not killed. At the same time, the death rate of young aphids is increased. Anyway, feeding of the two kinds of aphids has been controlled in a certain degree by gna gene when aphids can free to move in plants.

Animals↗

PubMed2003

Molecular characterization of a wheat--Thinopyrum ponticum partial amphiploid and its derivatives for resistance to leaf rust.

Leaf rust (caused by Puccinia triticina Eriks.) occurs annually in most wheat-growing areas of the world. Thinopyrum ponticum (Podp.) Z.-W. Liu & R.-C. Wang has provided several leaf rust resistance genes to protect wheat from this fungal disease. Three chromosome substitution lines, Ji806, Ji807, and Ji859, and two chromosome addition lines, Ji791 and Ji924, with a winter growing habit were developed from crosses between wheat (Triticum aestivum L. em Thell.) and the wheat - Th. ponticum partial amphiploid line 693. These lines were resistant to leaf rust isolates from China. Sequence-tagged site (STS) analysis with the J09-STS marker, which is linked to the gene Lr24, revealed that the partial amphiploid line 693 and all of the substitution and addition lines carried gene Lr24. Genomic in situ hybridization (GISH) analysis was carried out on chromosome preparations using total genomic DNA from Pseudoroegneria strigosa (M. Bieb) A. Löve (St genome, 2n = 14) as a probe in the presence of total genomic DNA from T. aestivum 'Chinese Spring' wheat (ABD genomes, 2n = 42). The GISH analysis demonstrated that these lines had a pair of chromosomes displaying the typical pattern of a Js genome chromosome. This indicates that the chromosome that carries gene Lr24 belonged to the Js genome of Th. ponticum. In addition to 40 wheat chromosomes, eight Js and eight J genome chromosomes were also differentiated by GISH in the partial amphiploid line 693. Since most sources of Lr24 have a red grain color, the white-colored seeds in all of these substitution and addition lines, together with high protein content in some of the lines, make them very useful as a donor source for winter wheat breeding programs.

Chromosomes, Plant↗

PubMed2003

[The characters and gene expression of rice seed proteins].

As an important nitrogen source of human being. The composition, structure and synthesis of rice storage protein were concerned by scientists. Now people know a lot about the structure ,expression patterns of rice glutelin genes. On the basis of these knowledge, we may improve the quality of rice grain and use it to produce foreign proteins. In this paper we summarize the knowledge about rice storage proteins that we have got in these years.

English Abstract↗

PubMed2002

[Advances in studies of genome-specific repetitive DNA sequences in wheat and related species].

In this paper we review recent advances in studies of several aspects of genome specific repetitive DNA sequences in wheat and related species. The available results demonstrate that genome specific repetitive DNA sequences are important components of genome specificity in wheat and related species. Research on genome specific repetitive DNA sequences is essential to the elucidation of genome function. The application of genome specific repetitive DNA sequences will aid molecular cytogenetic studies in wheat and related species and contributes to genetic improvement of common wheat.

English Abstract↗