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1.
Summary We have found that guanidine acetate catalyses the transformation of a -benzyl-aspartyl peptide (Boc-Asp-(OBzl)-Leu-Trp-OMe) to an aminosuccinyl peptide (Boc-Asu-Leu-Trp-OMe). The reaction was accompanied by partial epimerization. However, not even a small amount of epimerization could be detected when the aminosuccinyl peptide was synthesised from Boc-Asp-Leu-Trp-OMe with the addition of DIC, HOPfp and guanidine acetate (as a catalyst). This reaction seems to be suitable for the epimerization-free solid phase synthesis of aminosuccinyl peptides, e.g. Asu6-Lamprey-III-GnRH (Glp-His-Trp-Ser-His-Asu-Trp-Lys-Pro-Gly-NH2). 相似文献
2.
Thermal sensitivity and radiosensitization in V79 cells after BrdUrd or IdUrd incorporation 总被引:1,自引:0,他引:1
Chinese hamster V79 cells were exposed to 10(-5) moles/liter bromodeoxyuridine (BrdUrd) or iododeoxyuridine (IdUrd) for 16 or 29 hr and then tested for thermal sensitivity, radiosensitivity, and sensitivity to the combined treatments of heat and radiation. BrdUrd and IdUrd treatment of cells resulted in enhanced radiosensitivity which increased with exposure time but had little or no effect on thermal sensitivity. For 42.0 degrees C heating, no effect was observed, while for 45.0 degrees C heating, a small decrease in thermal sensitivity occurred for both 16- and 29-hr exposure times, in the combined treatment of heat and radiation, the presence of BrdUrd or IdUrd resulted in about the same thermal enhancement in radiosensitivity. BrdUrd and IdUrd uptake into cellular DNA were measured using high-pressure liquid chromatography and, after a 29-hr exposure to 10(-5) moles/liter of BrdUrd or IdUrd, approximately 40% of the thymidine was substituted. 相似文献
3.
It is thought that changes in gene expression in the brain mediate chronic ethanol-induced complex behaviors such as tolerance, dependence, and sensitization, and also relate to ethanol-induced brain toxicity. Using high-density filter-based cDNA microarrays (GeneFilters), we analyzed the expression of over 5000 genes in the dorsal hippocampus of rats treated with 12% ethanol or tap water for 15 months. Ethanol-induced changes in gene expression were particularly prominent in two groups of genes. One group consisted of oxidoreductases, including ceruloplasmin, uricase, branched-chain alpha-keto acid dehydrogenase, NADH ubiquinone oxidoreductase, P450, NAD+-isocitrate dehydrogenase, and cytochrome c oxidase, which may be related to ethanol-induced oxidative stress. The other group of genes included ADP-ribosylation factor, RAS related protein rab10, phosphatidylinositol 4-kinase, dynein-associated polypeptides, and dynamin-1, which seem to be involved in membrane trafficking. The results may reveal some of the pathways involved in ethanol-induced pathophysiological changes. 相似文献
4.
A mesophilic wine yeast, Saccharomyces cerevisiae CSIR Y217 K
–
R
– was subjected to the K2 killer effect of Saccharomyces cerevisiae T206 K
+
R
+ in a liquid grape medium. The lethal effect of the K2 mycoviral toxin was confirmed by methylene blue staining. Scanning electron microscopy of cells from challenge experiments revealed rippled cell surfaces, accompanied by cracks and pores, while those unaffected by the toxin, as in the control experiments, showed a smooth surface. Transmission electron microscopy revealed that the toxin damaged the cell wall structure and perturbed cytoplasmic membranes to a limited extent. 相似文献
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6.
Zahava Vadasz Tharwat Haj Katalin Halasz Itzhak Rosner Gleb Slobodin Dina Attias Aharon Kessel Ofra Kessler Gera Neufeld Elias Toubi 《Arthritis research & therapy》2012,14(3):R146
Introduction
Semaphorin 3A (sema3A) and neuropilin-1 (NP-1) play a regulatory role in immune responses and have a demonstrated effect on the course of collagen induced arthritis. This study was undertaken to evaluate the role of sema3A and NP-1 in the pathogenesis of systemic lupus erythematosus (SLE) and the specific effect of sema3A on the auto-reactive properties of B cells in SLE patients.Methods
Thirty two SLE and 24 rheumatoid arthritis (RA) patients were assessed and compared with 40 normal individuals. Sema3A serum levels were measured and correlated with SLE disease activity. The in vitro effect of sema3A in reducing Toll-like receptor 9 (TLR-9) expression in B cells of SLE patients was evaluated.Results
Sema3A serum levels in SLE patients were found to be significantly lower than in RA patients (55.04 ± 16.30 ng/ml versus 65.54 ± 14.82 ng/ml, P = 0.018) and lower yet than in normal individuals (55.04 ± 16.30 ng/ml versus 74.41 ± 17.60 ng/ml, P < 0.0001). Altered serum sema3A levels were found to be in inverse correlation with SLE disease activity, mainly with renal damage. The expression of both sema3A and NP-1 on B cells from SLE patients was significantly different in comparison with normal healthy individuals. Finally, when sema3A was co-cultured with cytosine-phosphodiester-guanine oligodeoxynucleotides (CpG-ODN)-stimulated B cells of SLE patients, their TLR-9 expression was significantly reduced, by almost 50% (P = 0.001).Conclusions
This is the first study in which a reduced serum level of sema3A was found in association with SLE disease activity. It also raises the possibility that sema3A may have a regulatory function in SLE. 相似文献7.
Danielle P. Moreira Karina Griesi-Oliveira Ana L. Bossolani-Martins Naila C. V. Louren?o Vanessa N. O. Takahashi Kátia M. da Rocha Eloisa S. Moreira Estev?o Vadasz Joanna Goes Castro Meira Debora Bertola Eoghan O’ Halloran Tiago R. Magalh?es Agnes C. Fett-Conte Maria Rita Passos-Bueno 《PloS one》2014,9(9)
Copy number variations (CNVs) are an important cause of ASD and those located at 15q11-q13, 16p11.2 and 22q13 have been reported as the most frequent. These CNVs exhibit variable clinical expressivity and those at 15q11-q13 and 16p11.2 also show incomplete penetrance. In the present work, through multiplex ligation-dependent probe amplification (MLPA) analysis of 531 ethnically admixed ASD-affected Brazilian individuals, we found that the combined prevalence of the 15q11-q13, 16p11.2 and 22q13 CNVs is 2.1% (11/531). Parental origin could be determined in 8 of the affected individuals, and revealed that 4 of the CNVs represent de novo events. Based on CNV prediction analysis from genome-wide SNP arrays, the size of those CNVs ranged from 206 kb to 2.27 Mb and those at 15q11-q13 were limited to the 15q13.3 region. In addition, this analysis also revealed 6 additional CNVs in 5 out of 11 affected individuals. Finally, we observed that the combined prevalence of CNVs at 15q13.3 and 22q13 in ASD-affected individuals with epilepsy (6.4%) was higher than that in ASD-affected individuals without epilepsy (1.3%; p<0.014). Therefore, our data show that the prevalence of CNVs at 15q13.3, 16p11.2 and 22q13 in Brazilian ASD-affected individuals is comparable to that estimated for ASD-affected individuals of pure or predominant European ancestry. Also, it suggests that the likelihood of a greater number of positive MLPA results might be found for the 15q13.3 and 22q13 regions by prioritizing ASD-affected individuals with epilepsy. 相似文献
8.
The analysis and results presented in this paper provide conclusive evidence to distinguish between the delay effect and the
lag as two biologically distinct phenomena. It therefore dispels the incorrect notion that delay effects represented by delay
differential equations are the biological reason behind the lag phase in microorganism growth. The resulting consequence so
far is that the only other reason for the lag phase is the existence of unstable stationary states. The latter are a result
of accounting for the microbial metabolic mass transfer in the population growth process. 相似文献
9.
Effects of social isolation and the time of day on testosterone levels in plasma of C57BL/6By and BALB/cBy mice 总被引:2,自引:0,他引:2
Adult male C57BL/6By and BALB/cBy mice were housed either in large groups (20 per cage) or individually, and levels of plasma testosterone were measured in samples taken in the morning (9 to 10 A.M.) and in the evening (9 to 10 P.M.). No significant strain differences were found in testosterone levels, but the mean testis weight was significantly higher in the BALB/cBy strain. Two-way analysis of variances of pooled plasma testosterone data showed that social isolation of males results in a significant increase in A.M. (but not P.M.) testosterone concentrations and increased testis weight in both strains. Our results suggest that differential housing of a social species can affect testicular function. Since testicular function can also be influenced by the time of day, the question is raised whether the expression of circadian variation in plasma testosterone level is dependent on population density. 相似文献
10.
Summary L-tyrosine-3-hydroxylase (TH) is the first and rate limiting enzyme in the biosynthetic pathway of catecholamine neurotransmitters (dopamine, noradrenaline, adrenaline). Implication of dopamine (DA) in various psychopathological phenomena, such as schizophrenia, has considerably contributed to the intensity of investigation of basic biochemical regulation of TH by activation and induction. Here we consider a third, constitutional (genotypic) aspect of regulation and present evidence that differences in mesencephalic (TH/SN), striatal (TH/CS), and hypothalamic (TH/HT) TH activity between virtually isogeneic strains of mice can be explained by segregating genetic factors. Biometrical genetic analysis of progenitor strains and their crosses indicated significant additive gene effects for TH/SN, TH/CS, and TH/HT, whereas dominance effects were statistically non-significant. A monogenic model of inheritance for TH/SN and TH/CS could not be rejected, while more than one gene was indicated for TH/HT. Significant positive phenotypic correlations were found in genetically segregating populations among mesencephalic, striatal and hypothalamic TH activities. This would suggest that some common genetic factors (or linked genes) are involved in the genetic variation of all three traits. A genetic selection experiment to elucidate the cellular and biochemical mechanisms underlying these variations is in progress. 相似文献