Adrenomedullin binding protein-1 modulates vascular responsiveness to adrenomedullin in late sepsis

Adrenomedullin (AM), a potent vasodilatory peptide, plays an important role in initiating the hyperdynamic response during the early stage of sepsis. Moreover, the reduced vascular responsiveness to AM appears to be responsible for the transition from the early, hyperdynamic to the late, hypodynamic phase of sepsis. Although the novel specific AM binding protein-1 (AMBP-1) enhances AM-mediated action in a cultured cell line, it remains to be determined whether AMBP-1 plays any role in modulating vascular responsiveness to AM during sepsis. To study this, adult male rats were subjected to sepsis by cecal ligation and puncture (CLP). The thoracic aorta was harvested for determination of AM-induced vascular relaxation. Aortic levels of AMBP-1 were determined by Western blot analysis, and AM receptor gene expression in the aortic tissue was assessed by RT-PCR. The results indicate that AMBP-1 significantly enhanced AM-induced vascular relaxation in aortic rings from sham-operated animals. Although vascular responsiveness to AM decreased at 20 h after CLP (i.e., the late, hypodynamic stage of sepsis), addition of AMBP-1 in vitro restored the vascular relaxation induced by AM. Moreover, the aortic level of AMBP-1 decreased significantly at 20 h after CLP. In contrast, AM receptor gene expression was not altered under such conditions. These results, taken together, suggest that AMBP-1 plays an important role in modulating vascular responsiveness to AM, and the reduced AMBP-1 appears to be responsible for the vascular AM hyporesponsiveness observed during the hypodynamic phase of sepsis.     

A PCR-based semiquantitative assay of DNA impurities in recombinant protein preparations

A semiquantitative assay of DNA impurities in preparations of human recombinant insulin is described. The assay is based on the detection of a fragment of the ampicillin-resistant gene within the producer strain DNA by PCR. The analysis of PCR products of the studied preparations and PCR products containing known amounts of E. coli total DNA enabled a quantitative determination of the producer strain DNA content in the preparations under study. The sensitivity of the method is 7 pg of E. coli DNA per 10 microg of human recombinant insulin. The high sensitivity of the method allows us to recommend it for the quantitative determination of DNA content in recombinant preparations that do not inhibit PCR.     

Changes of phenolic metabolism and oxidative status in nitrogen-deficient Matricaria chamomilla plants

The effects of nitrogen deficiency on selected physiological attributes, phenylalanine ammonia-lyase (PAL, EC. 4.3.1.5) activity, phenolic contents, peroxidase (EC. 1.11.1.7) and catalase (EC. 1.11.1.6) activities, lipid peroxidation status and H₂O₂ accumulation were studied in N-deficient Matricaria chamomilla (L.) over 12 days. N deficiency enhanced root growth and inhibited shoot growth. Chlorophyll composition and F _v/F _m were not affected by N stress, but nitrogen and soluble proteins decreased in both the rosettes and the roots. PAL activity, expressed per mg protein, was enhanced in N-deficient rosettes and tended to decrease by the end of the experiment, while in the roots PAL activity was maintained. Total phenolic contents increased in both rosettes and roots. Peroxidase and catalase activities in N-deficient rosettes tended to decrease by the end of the experiment, while in the roots they increased on the 12th day of deficiency. Furthermore, lipid peroxidation status increased in N-deficient roots on the 12th day, indicating that antioxidative protection was insufficient to scavenge reactive oxygen species being generated. Surprisingly, H₂O₂ content was even lower in N-deficient roots by the end of the experiment, while in the leaves increased. This observation in correlation to lipid peroxidation and H₂O₂ degradation is discussed. The importance of PAL activity and phenolic metabolites in combination with antioxidative enzymes for plant protection against oxidative stress and the significance of PAL activity for the mobilization of N availability in N-deficient tissue are also discussed in view of existing information.     

Selenomethionine induces polyamine biosynthesis in regenerating rat liver tissue

Summary. Our study was undertaken to elucidate the effects of selenomethionine (SeMet) on polyamine metabolism in regenerating rat liver tissue, as useful model of rapidly growing normal tissue. We have examined the levels of spermine, spermidine and putrescine in liver tissue. At the same time we have evaluated the activities of polyamine oxidase (PAO) and diamine oxidase (DAO), the catabolic enzymes of polyamine metabolism. The obtained results suggest that polyamine levels in regenerating liver tissue, at 7^th day after two-thirds partial hepatectomy, were higher in comparison with control group. The administration of selenomethionine to hepatectomized animals during seven days, in a single daily dose of 2.5 μg/100 g body weight, increases the amount of spermine and spermidine; the level of putrescine does not change under the influence of SeMet in regenerating rat liver tissue. PAO activity is lower in regenerating hepatic tissue than in control group. Supplementation of hepatectomized animals with SeMet significantly decreases the activity of this enzyme. DAO activity was significantly higher in hepatectomized and in operated animals treated with SeMet compared to the sham-operated and control ones. The differential sensitivity observed in our model of highly proliferating normal tissue to SeMet, compared with the reported anticancer activity of this molecule is discussed.     

Homozygous mutations in fibroblast growth factor 3 are associated with a new form of syndromic deafness characterized by inner ear agenesis, microtia, and microdontia

We identified nine individuals from three unrelated Turkish families with a unique autosomal recessive syndrome characterized by type I microtia, microdontia, and profound congenital deafness associated with a complete absence of inner ear structures (Michel aplasia). We later demonstrated three different homozygous mutations (p.S156P, p.R104X, and p.V206SfsX117) in the fibroblast growth factor 3 (FGF3) gene in affected members of these families, cosegregating with the autosomal recessive transmission as a completely penetrant phenotype. These findings demonstrate the involvement of FGF3 mutations in a human malformation syndrome for the first time and contribute to our understanding of the role this gene plays in embryonic development. Of particular interest is that the development of the inner ear is completely disturbed at a very early stage--or the otic vesicle is not induced at all--in all of the affected individuals who carried two mutant FGF3 alleles.     

Protein glycosylation in pmt mutants of Saccharomyces cerevisiae. Influence of heterologously expressed cellobiohydrolase II of Trichoderma reesei and elevated levels of GDP-mannose and cis-prenyltransferase activity

Protein O-mannosylation has been postulated to be critical for production and secretion of glycoproteins in fungi. Therefore, understanding the regulation of this process and the influence of heterologous expression of glycoproteins on the activity of enzymes engaged in O-glycosylation are of considerable interest. In this study we expressed cellobiohydrolase II (CBHII) of T. reesei, which is normally highly O-mannosylated, in Saccharomyces cerevisiae pmt mutants partially blocked in O-mannosylation. We found that the lack of Pmt1 or Pmt2 protein O-mannosyltransferase activity limited the glycosylation of CBHII, but it did not affect its secretion. The S. cerevisiae pmt1Delta and pmt2Delta mutants expressing T. reesei cbh2 gene showed a decrease of GDP-mannose level and a very high activity of cis-prenyltransferase compared to untransformed strains. On the other hand, elevation of cis-prenyltransferase activity by overexpression of the S. cerevisiae RER2 gene in these mutants led to an increase of dolichyl phosphate mannose synthase activity, but it did not influence the activity of O-mannosyltransferases. Overexpression of the MPG1 gene increased the level of GDP-mannose and stimulated the activity of mannosyltransferases elongating O-linked sugar chains, leading to partial restoration of CBHII glycosylation.     

黄河首曲-玛曲县高寒草甸沙化演替进程中群落结构及种群生态位特征

以甘肃省玛曲县高寒沙化草甸为对象,应用空间序列代替时间序列的方法,对其不同沙化演替阶段植物群落主要种群结构及其生态位特征进行了研究.结果表明:(1)随着沙化演替的进行,物种组成数呈单峰式曲线变化规律,在轻度沙化阶段物种数最多(43种),禾草类和豆科类物种的重要值和生态位宽度均呈逐渐减少规律,优势度逐渐减弱;在极度沙化阶段(除垂穗披碱草外)几乎完全消失,莎草类和杂类草一些物种的重要值和生态位宽度则均呈逐渐增大规律,优势度逐渐增加,并在重度或极度沙化阶段成为优势种、次优势种或重要伴生种;随沙化演替进程,蒲公英、狼毒和乳白香青等物种则表现出波动性,最后消失,物种组成和数量的变化导致沙化演替进程中高寒草甸草场质量逐渐降低.(2)相邻沙化演替阶段植物群落的物种组成相似性指数较高,而相距较远的沙化演替阶段植物群落的物种组成相似性指数较小,沙化演替系列两个极端阶段的植物群落的物种组成相似性指数最小.(3)垂穗披碱草在整个沙化演替过程中重要值和生态位宽度均逐渐减小,但其值都较大.(4)生态位总宽度占前5位的物种依次是:垂穗披碱草、莓叶委陵菜、矮嵩草、高山唐松草和苔草,其值分别为1.653、1.438、1.387、1.295和1.204.(5)种群之间生态位重叠系数的平均值随沙化程度加深呈单峰式曲线变化规律,轻度沙化阶段种群的生态位重叠程度较高,为0.824.     

The relationship between the presence of ADHD and certain candidate gene polymorphisms in a Turkish sample

Due to the high heritability of attention-deficit hyperactivity disorder (ADHD), parents of children with ADHD appear to represent a good sample group for investigating the genetics of the disorder. The aim of this study was to investigate the association between ADHD and six polymorphisms in five candidate genes [5-HT2A (rs6311), NET1 (rs2242447), COMT (rs4818), NTF3 (rs6332), SNAP-25 (rs3746544) and (rs1051312)]. We included 228 parents of children diagnosed with ADHD and 109 healthy parents as the control group. The polymorphisms were genotyped using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) assays and analyzed using the chi-square test and the multinomial logit model. SNAP-25 (rs3746544) polymorphism was associated with loading for ADHD, while 5-HT2A (rs6311) and NET1 (rs2242447) polymorphisms were associated with ADHD. On the other hand, there was no significant association between the SNAP-25 (rs1051312), NTF3 (rs6332), or COMT (rs4818) gene polymorphisms and ADHD.     

Extracellular matrix components in uterine leiomyoma and their alteration during the tumour growth

It was found that both normal human myometrium and uterine leiomyoma contain several glycosaminoglycans. In contrast to many normal and tumour tissues the amount of hyaluronic acid is very low and the proportional amount of sulphated glycosaminoglycans is distinctly higher. It is of interest that heparan sulphate is the major glycosaminoglycan component both in normal myometrium, and in leiomyoma. The amount of hyaluronic acid in myometrium and in the leiomyoma is very low. No significant change in hyaluronate content was observed during the tumour growth. In contrast to that the amount of some sulphated glycosaminoglycans (heparan sulphate, keratan sulphate, chondroitin sulphates and heparin) distinctly increased. It is suggested that some of the GAGs participate in the creation of a storage depot for biologically active molecules (growth factors, enzymes) which are thereby stabilized and protected. Hydrolytic degradation of some GAGs may result in the release of some cytokines which may promote the tumour growth and stimulate collagen biosynthesis by tumour cells.