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Rong Gao

Publications and source records attributed to Rong Gao.

41 records · Page 3Linked to original sources
PubMed2002

The uptake of tocopherols by RAW 264.7 macrophages.

BACKGROUND: Alpha-Tocopherol and gamma-tocopherol are the two major forms of vitamin E in human plasma and the primary lipid soluble antioxidants. The dietary intake of gamma-tocopherol is generally higher than that of alpha-tocopherol. However, alpha-tocopherol plasma levels are about four fold higher than those of gamma-tocopherol. Among other factors, a preferential cellular uptake of gamma-tocopherol over alpha-tocopherol could contribute to the observed higher plasma alpha-tocopherol levels. In this investigation, we studied the uptake and depletion of both alpha-tocopherol and gamma-tocopherol (separately and together) in cultured RAW 264.7 macrophages. Similar studies were performed with alpha-tocopheryl quinone and gamma-tocopheryl quinone, which are oxidation products of tocopherols. RESULTS: RAW 264.7 macrophages showed a greater uptake of gamma-tocopherol compared to alpha-tocopherol (with uptake being defined as the net difference between tocopherol transported into the cells and loss due to catabolism and/or in vitro oxidation). Surprisingly, we also found that the presence of gamma-tocopherol promoted the cellular uptake of alpha-tocopherol. Mass balance considerations suggest that products other than quinone were formed during the incubation of tocopherols with macrophages. CONCLUSION: Our data suggests that gamma-tocopherol could play a significant role in modulating intracellular antioxidant defence mechanisms. Moreover, we found the presence of gamma-tocopherol dramatically influenced the cellular accumulation of alpha-tocopherol, i.e., gamma-tocopherol promoted the accumulation of alpha-tocopherol. If these results could be extrapolated to in vivo conditions they suggest that gamma-tocopherol is selectively taken up by cells and removed from plasma more rapidly than alpha-tocopherol. This could, in part, contribute to the selective maintenance of alpha-tocopherol in plasma compared to gamma-tocopherol.

Journal Article↗
PubMed2002

Ratcheting up vir gene expression in Agrobacterium tumefaciens: coiled coils in histidine kinase signal transduction.

The transmembrane histidine kinase VirA is responsible for the recognition of information from several plant-derived xenognostic signals that control gene transfer between Agrobacterium tumefaciens and its eukaryotic host. As with other histidine autokinases, VirA appears to exist as a homodimer within the inner membrane of the bacterium. In this study, we identify the putative homodimeric coiled-coil-like motifs Helix TM2 (amino acids (aa) 259-288) and Helix C (aa 293-327) within the previously assigned signal input domain. The functional importance of these coiled-coil interactions in signal-mediated VirA activation is investigated by the construction of fusion proteins with the leucine zipper domain of the transcription factor GCN4. Replacement of the membrane-spanning and periplasmic domains of VirA with the GCN4 leucine zipper gave functional proteins with increased signal-induced vir gene expression. When the GCN4 fusion was used to conformationally bias the interface of the Helix C coiled coil, constitutively active chimeras were created. The activity of these constructs was dependent on the interface of the Helix C coiled coil, and a ratchet model is proposed in which VirA activation is achieved by signal-induced switching of the interfaces of the homodimer. Since VirA functions as a transducer and integrates various host cues indirectly, these data highlight its role as an "antenna" for the tumor-inducing (Ti) plasmid, able to monitor the host proteome so as to select for successful xenognostic signaling strategies.

Agrobacterium tumefaciens↗
PubMed2002

[Sero-and molecular epidemiology of the gene of different ORF of transfusion transmitted virus (TTV) in different population of China].

BACKGROUND: To investigate the distribution of anti-TTV antibody and the different ORF gene in different populations of China. METHODS: The antibody to TTV in sera collected from different population were detected by using ELISA and the different ORF genes were amplified with PCR. RESULTS: The positive rates of TTV ORF1 DNA, ORF2 DNA and the antibody in various populations were as follows: 16.0% (12/75), 10.7% (8/75) and 25.3% (19/75) in paid blood donors; 10.0 (3/30), 16.7% (5/30) and 16.7% (5/30) in patients with hepatitis A, 47.5% (19/40), 42.5% (17/40) and 22.5% (9/40) in patients with hepatitis B; 42.9% (15/35), 37.1% (13/35) and 28.6% (10/35) in patients with hepatitis C; 20.0% (3/15), 26.7% (4/15) and 13.3% (2/15)in patients with hepatitis D; 16.7% (2/12),16.7% (2/12) and 33.3% (4/12)in patients with hepatitis E; 23.8% (5/21), 38.1% (8/21) and 23.8% (5/21) in patients with hepatitis G; 61.1% (11/18), 50.0% (9/18) and 44.4% (8/18) in patients with non A-G hepatitis, respectively. The positive rate of different ORF DNA had no significant difference. Significant differences were found in the positive rates of TTV DNA in various populations. There was no relationship between the TTV DNA and the antibody to TTV. CONCLUSIONS: The antibody to TTV and TTV DNA were found in every population of China. There was no significant difference in the positive rates of TTV DNA between ORF1 and ORF2. The positive rate in patients with non A-G hepatitis was higher than those in the other populations.

Adolescent↗
PubMed2002

[Construction and expression of somatostatin (S14) and hepatitis B surface antigen gene in yeast Pichia pastoris].

To construct the ss/HBsAg protein gene-engineering vaccine for developing the diagnosis and cure tumors in clinical medicine and promoting the growth in animal husbandry production. A pair of primers were designed according separately to the sequence of Somatostatin gene(S14) and HBsAg gene. Their gene fragments were separately amplified by using PCR and cloned, following sequencing, the DNA fragments were inserted into pBluescript vector. Then the ss/HBsAg chimera was constructed and was cloned into pPICZaA plasmid, and transformed into electroporated Pichia pastoris. High yield protein expression was obtained. Expressed protein was proved with high specificity and it's molecular weigh was about 28 KD identified by SDS-PAGE and Western blot.

Artificial Gene Fusion↗