17β—雌二醇抑制内皮素诱导的血管平滑肌细胞增殖作用

目的和方法：利用组织块贴壁法进行大鼠VSMC培养,胰蛋白酶分散细胞法传代。实验采用第4-6代细胞。采用氚-胸腺嘧啶核苷（[^3H]-TdR)掺入和细胞计数来作为VSMC增殖的指标,以RT-PCR的方法检测ETAR的表达,观察17β-雌二醇（E2）对内皮素-I（endothelin-l,ET-1)介导的血管平滑肌细胞（VSMC）增殖反应以及对内皮素A型受体（ETAR）表达的影响。结果：ETAR特异性拮抗剂BQ123能完全阻断ET-1介导的VSMC增殖反应;E2可明显抑制ET-1促进VSMC增殖的作用,RT-PCR结果显示E2能抑制ETAR的表达,12h时抑制作用最为明显;E2受体阻断剂Tamoxifen亦能部分抑制ET-1对VSMC的增殖及ETAR的mRNA的表达。结论：ET-1促进VSMC增殖作用主要通过ETAR介导的,雌激素可通过抑制ETARmRNA表达来发挥对ET-1促进VSMC增殖的抑制作用。     

Downregulation of caffeic acid 3-O-methyltransferase and caffeoyl CoA 3-O-methyltransferase in transgenic alfalfa. impacts on lignin structure and implications for the biosynthesis of G and S lignin

Transgenic alfalfa plants were generated harboring caffeic acid 3-O-methyltransferase (COMT) and caffeoyl CoA 3-O-methyltransferase (CCOMT) cDNA sequences under control of the bean phenylalanine ammonia-lyase PAL2 promoter. Strong downregulation of COMT resulted in decreased lignin content, a reduction in total guaiacyl (G) lignin units, a near total loss of syringyl (S) units in monomeric and dimeric lignin degradation products, and appearance of low levels of 5-hydroxy guaiacyl units and a novel dimer. No soluble monolignol precursors accumulated. In contrast, strong downregulation of CCOMT led to reduced lignin levels, a reduction in G units without reduction in S units, and increases in beta-5 linked dimers of G units. Accumulation of soluble caffeic acid beta-d-glucoside occurred only in CCOMT downregulated plants. The results suggest that CCOMT does not significantly contribute to the 3-O-methylation step in S lignin biosynthesis in alfalfa and that there is redundancy with respect to the 3-O-methylation reaction of G lignin biosynthesis. COMT is unlikely to catalyze the in vivo methylation of caffeic acid during lignin biosynthesis.     

Programmed translational frameshifting is likely required for expressions of genes encoding putative nuclear protein kinases of the ciliate Euplotes octocarinatus

Three macronuclear genes encoding putative nuclear protein kinases of the ciliate Euplotes octocarinatus syngen 1 were isolated and sequenced. All three deduced gene products share significant properties with a group of recently identified nuclear serine/threonine protein kinases named Ndr. The three predicted proteins contain the twelve conserved catalytic subdomains of protein kinases and 22 near universally-conserved amino acids residues that are characteristic of serine/threonine protein kinases. In addition, there is an approximately 30 amino acid-peptide insertion between subdomains VII and VIII that contains a potential nuclear localization signal. Sequence analysis suggests that expression of the Eondr2 gene requires a + 1 programmed translational frameshift for its translation. Comparison of the deduced EoNdr2 with other known Ndr protein kinases implies that a + 1 ribosomal frameshift occurs at the motif AAATAA.     

Combine-ARMS: a rapid and cost-effective protocol for molecular characterization of beta-thalassemia in Malaysia

Beta-thalassemia major patients have chronic anemia and are dependent on blood transfusions to sustain life. Molecular characterization and prenatal diagnosis of beta3-thalassemia is essential in Malaysia because about 4.5% of the population are heterozygous carriers for beta-thalassemia. The high percentage of compound heterozygosity (47.62%) found in beta-thalassemia major patients in the Thalassaemia Registry, University of Malaya Medical Centre (UMMC), Malaysia, also supports a need for rapid, economical, and sensitive protocols for the detection of beta-thalassemia mutations. Molecular characterization of beta-thalassemia mutations in Malaysia is currently carried out using ARMS, which detects a single beta-thalassemia mutation per PCR reaction. We developed and evaluated Combine amplification refractory mutation system (C-ARMS) techniques for efficient molecular detection of two to three beta-thalassemia mutations in a single PCR reaction. Three C-ARMS protocols were evaluated and established for molecular characterization of common beta-thalassemia mutations in the Malay and Chinese ethnic groups in Malaysia. Two C-ARMS protocols (cd 41-42/IVSII #654 and -29/cd 71-72) detected the beta-thalassemia mutations in 74.98% of the Chinese patients studied. The CARMS for cd 41-42/IVSII #654 detected beta-thalassemia mutations in 72% of the Chinese families. C-ARMS for cd 41-42/IVSI #5/cd 17 allowed detection of beta-thalassemia mutations in 36.53% of beta-thalassemia in the Malay patients. C-ARMS for cd 41-42/IVSI #5/cd 17 detected beta-thalassemia in 45.54% of the Chinese patients. We conclude that C-ARMS with the ability to detect two to three mutations in a single reaction provides more rapid and cost-effective protocols for beta-thalassemia prenatal diagnosis and molecular analysis programs in Malaysia.     

Hypertension and its related factors in Taiwanese elderly people

BACKGROUND: Our study used data collected in Chung-Hsing Village in May 1998 to evaluate the prevalence of hypertension and its correlates in Taiwanese elderly people. METHODS: All of individuals aged 65 and over were recruited as study subjects. A total of 1,093 persons, out of 1,774 registered residents, were contacted by face-to-face interview The response rate was 61.6 percent. However, only 586 respondents had blood tests and completed questionnaires. Analysis in this study was based on these 586 subjects. In order to study the significant correlates of hypertension, the t-test, chi-square analysis, and multivariate logistic regression were used. RESULTS: Our results showed that 66 percent were men and 34 percent were women. The mean age was 73.1 +/- 5.3 years. The proportions of hypertension were 53.09 percent in men and 56.06 percent in women (p > 0.05). After controlling the other covariates, the multivariate logistic regression analysis showed that the significant related factors of hypertension were obesity (OR = 1.88, 95 percent CI = 1.06-3.34, p < 0.05) and renalfunction impairment (OR = 1.69, 95 percent CI = 1.02-2.80, p < 0.05). CONCLUSIONS: The prevalence of hypertension was high in elderly people. Hypertension is significantly associated with obesity and renalfunction impairment in elderly people.     

Specific detection of Bradyrhizobium and Rhizobium strains colonizing rice (Oryza sativa) roots by 16S-23S ribosomal DNA intergenic spacer-targeted PCR

In addition to forming symbiotic nodules on legumes, rhizobial strains are members of soil or rhizosphere communities or occur as endophytes, e.g., in rice. Two rhizobial strains which have been isolated from root nodules of the aquatic legumes Aeschynomene fluminensis (IRBG271) and Sesbania aculeata (IRBG74) were previously found to promote rice growth. In addition to analyzing their phylogenetic positions, we assessed the suitability of the 16S-23S ribosomal DNA (rDNA) intergenic spacer (IGS) sequences for the differentiation of closely related rhizobial taxa and for the development of PCR protocols allowing the specific detection of strains in the environment. 16S rDNA sequence analysis (sequence identity, 99%) and phylogenetic analysis of IGS sequences showed that strain IRBG271 was related to but distinct from Bradyrhizobium elkanii. Rhizobium sp. (Sesbania) strain IRBG74 was located in the Rhizobium-Agrobacterium cluster as a novel lineage according to phylogenetic 16S rDNA analysis (96.8 to 98.9% sequence identity with Agrobacterium tumefaciens; emended name, Rhizobium radiobacter). Strain IRBG74 harbored four copies of rRNA operons whose IGS sequences varied only slightly (2 to 9 nucleotides). The IGS sequence analyses allowed intraspecies differentiation, especially in the genus Bradyrhizobium, as illustrated here for strains of Bradyrhizobium japonicum, B. elkanii, Bradyrhizobium liaoningense, and Bradyrhizobium sp. (Chamaecytisus) strain BTA-1. It also clearly differentiated fast-growing rhizobial species and strains, albeit with lower statistical significance. Moreover, the high sequence variability allowed the development of highly specific IGS-targeted nested-PCR assays. Strains IRBG74 and IRBG271 were specifically detected in complex DNA mixtures of numerous related bacteria and in the DNA of roots of gnotobiotically cultured or even of soil-grown rice plants after inoculation. Thus, IGS sequence analysis is an attractive technique for both microbial ecology and systematics.     

Isolation of a highly copper-tolerant yeast, Cryptococcus sp., from the Japan Trench and the induction of superoxide dismutase activity by Cu2+

Thirteen yeast strains were isolated from deep-sea sediment samples collected at a depth of 4500 m to 6500 m in the Japan Trench. Amongst them, strain N6 possessed high tolerance against Cu²⁺ and could grow on yeast extract/peptone/dextrose/agar containing 50 mM CuSO₄. Analysis of the 18S rDNA sequence indicates strain N6 belongs to the genus Cryptococcus. In contrast, the type strain of C. albidus, a typical marine yeast Rhodotorula ingeniosa and Saccharomyces cerevisiae did not grow at high concentrations of CuSO₄. Superoxide dismutase (SOD) catalyzes the scavenging of superoxide radicals. The activity of SOD in cell extract of strain N6 was very weak (<1 mU g^–1 total protein) when the strain was grown in the absence of CuSO₄. However, the activity was stimulated (25.8 mU g^–1 total protein) when cells were grown with 1 mM CuSO₄ and further enhanced to 110 mU g^–1 total protein with 10 mM CuSO₄. Catalase activity was increased only 1.4 or 1.1-fold with 1 mM or 10 mM CuSO₄ in the growth medium, respectively. These results suggest that SOD may have a role in the defensive mechanisms against high concentrations of CuSO₄ in strain N6.