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1.
Marek’s disease viruses (MDV) belong to a sub-group of alphaherpesvirus in herpesviridae, and could be divided into 3 serogroups. Among them, serotype 1 could cause lymphoproliferative disease in chickens characterized by the formation of T-cell lymphoma…  相似文献   

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Spliceosomal Prp38 proteins contain a conserved amino-terminal domain, but only higher eukaryotic orthologs also harbor a carboxy-terminal RS domain, a hallmark of splicing regulatory SR proteins. We show by crystal structure analysis that the amino-terminal domain of human Prp38 is organized around three pairs of antiparallel α-helices and lacks similarities to RNA-binding domains found in canonical SR proteins. Instead, yeast two-hybrid analyses suggest that the amino-terminal domain is a versatile protein–protein interaction hub that possibly binds 12 other spliceosomal proteins, most of which are recruited at the same stage as Prp38. By quantitative, alanine surface-scanning two-hybrid screens and biochemical analyses we delineated four distinct interfaces on the Prp38 amino-terminal domain. In vitro interaction assays using recombinant proteins showed that Prp38 can bind at least two proteins simultaneously via two different interfaces. Addition of excess Prp38 amino-terminal domain to in vitro splicing assays, but not of an interaction-deficient mutant, stalled splicing at a precatalytic stage. Our results show that human Prp38 is an unusual SR protein, whose amino-terminal domain is a multi-interface protein–protein interaction platform that might organize the relative positioning of other proteins during splicing.  相似文献   

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Summary Molecular mechanisms of thermoinactivation of the thermostable -amylase of Bacillus caldovelox were examined. Monomolecular conformational processes were found to be the major causes of thermoinactivation at both pH 4.5 and 8.0. The enzyme possessed considerable additional thermostability at pH 8.0, with half-lives of 0.75 and 7.0 min at 90° C and pH 4.5 and 8.0, respectively. The amino acid composition was examined with respect to the underlying thermostability exhibited by this enzyme. The inherent thermostability exhibited may be due to the high proline content (4.47 mol%), but more likely due to the high content of residues forming hydrophobic bonds (60.89 mol%) allied to a low content of residues responsible for ionic interactions (28.34 mol%). Offprint requests to: C. T. Kelly  相似文献   

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Even though the incidence of pregnancies in the female recipients is lower and also chronic renal disease in male patients is associated with impaired spermatogenesis, the health of the children born to these patients was not studied. In this report, we discuss information on the growth and development of offspring of 248 male and female kidney recipient patients. Physical and routine clinical measurements of the 252 offspring (129 male and 123 female) born to these transplantation patients were made along with the intelligence tests. In some of these children chest X-ray and immune indices were assessed. Among the recipients, 219 males fathered 223 children with an average birth weight of 3,255 ± 374 g and 29 female recipients gave birth to 29 children with an average birth weight of 2,923 ± 551. While most of these children were normal, we noticed a case of soft double toe, a case of short tongue tie, five cases of marginal mental retardation, three cases of proteinuria, six cases of microscopic hematuria, 15 cases of low hemoglobin, and 21 cases with recurrent respiratory tract infections. We conclude that kidney transplantation has no significant impact on the growth, development, health, and intelligence of the offspring born to recipients.  相似文献   

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The pyrolyzate of the nondialyzable melanoidin prepared from glucose-ammonia reaction system (kept in pH 5.3~6.0 during the reaction) was fractionated to volatile fraction and nonvolatile fraction. Among the volatile components, two pyridines and four alkylpyrazines were identified. On the other hand, one imidazole compound and two β-hydroxypyridines isolated from the nonvolatile fraction were identified as 4(5)-methylimidazole, 3-hydroxypyridine and 2-methyl-5-hydroxypyridine, respectively. It is inferred that these compounds are not produced by the fission of the main skeleton in the melanoidin molecule, but formed by pyrolysis of the heterocyclic compounds present as a small moiety in the melanoidin.  相似文献   

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1. The developmental pattern and effect of cortisone on acid beta-galactosidase and neutral beta-galactosidase were studied in postnatal rats by a recently proposed method for their independent determination. 2. After birth the acid beta-galactosidase activity increases in the ileum, whereas it decreases slightly in the jejunum. On day 16 after birth the activity in the ileum decreases and in 20-day-old rats activity in both parts of the intestine decreases to adult values. In suckling animals the activity in the ileum exceeds the jejunal activity severalfold and in adult animals the activity in the jejunum is slightly higher than that in the ileum. 3. Neutral beta-galactosidase activity is high after birth and decreases in both jejunum and ileum after day 20 after birth. In 12-20-day-old rats activity in both parts is essentially the same, but in adult animals jejunal activity exceeds ileal activity four-to five-fold. 4. Cortisone (0.5, 2.0 or 5.0mg/100g body wt. daily for 4 days) does not influence the activity of either enzyme in 60-day-old rats. Acid beta-galactosidase activity is decreased after cortisone treatment in 8-, 12-, 16-and 18-day-old rats, with sensitivity to cortisone increasing with the approach of weaning. No effect of cortisone on acid beta-galactosidase is seen in 8-day-old rats. Neutral beta-galactosidase activity is increased in the ileum of 8-, 12-, 16- and 18-day old rats, but only in the jejunum of 8-and 12-day-old rats.  相似文献   

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By spectrofluorophotometric investigation on various kinds of Saké it was found that they have at least two kinds of fluorescent colors, the one is blue, the other yellowish green. The former is always more dominant than the latter, but is unstable although the intensities of both color decrease remarkably by treatment of active charcoal. Ferulic acid and harman as the blue fluorescent components are isolated, the former from Saké in young, the latter from Saké kept for a long time under direct sun light.  相似文献   

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Context Four gamma-glutamyltransferase (GGT) fractions with different molecular weights (big-, medium-, small- and free-GGT) are detectable in human plasma. Objective Verify if liver cells can release all four GGT fractions and if the spatial cell organization influences their release. Methods Hepatoma (HepG2) and melanoma (Me665/2/60) cells were cultured as monolayers or spheroids. GGT released in culture media was analysed by gel-filtration chromatography. Results HepG2 and Me665/2/60 monolayers released the b-GGT fraction, while significative levels of s-GGT and f-GGT were detectable only in media of HepG2-spheroids. Bile acids alone or in combination with papain promoted the conversion of b-GGT in s-GGT or f-GGT, respectively. Conclusions GGT is usually released as b-GGT, while s-GGT and f-GGT are likely to be produced in the liver extracellular environment by the combined action of bile acids and proteases.  相似文献   

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Ionizing radiation reduces the numbers of neurons expressing activity-regulated cytoskeleton-associated protein (Arc) in the hippocampal dentate gyrus (DG). It is currently unclear if that change relates to cognitive function. We assessed the effects of 1 Gy of head-only ??Fe-particle irradiation on hippocampus-dependent and hippocampus-independent fear conditioning and determined how those changes related to Arc expression within the DG. Irradiated mice that did not receive tone-shock pairings on day 1 showed less freezing in the same context on a second day and a lower fraction of Arc-expressing neurons in the free (lower) blade of the DG than sham-irradiated mice. Those data suggested reduced hippocampus-dependent spatial habituation learning. Changes in Arc expression in the free blade correlated positively with freezing in mice that did not receive tone-shock pairings. However, irradiated mice that did receive tone-shock pairings showed enhanced contextual freezing but a reduced percentage of Arc-expressing neurons in the enclosed (upper) blade. Changes in Arc expression correlated negatively with freezing in mice that received tone-shock pairings. In animals receiving cued fear conditioning, radiation did not affect cognitive performance or the fractions of Arc-expressing neurons. While the relationship between Arc expression and cognitive performance is complex, our data suggest that radiation effects on hippocampus-dependent cognition might depend on the prominence (salience) of environmental stimuli and blade-specific Arc expression.  相似文献   

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This paper explores the relationship between the economic turmoil generated by the Great Recession and the increase of secessionism. Some authors have stressed that the Great Recession triggered changes in territorial preferences and, in the context of a conflict between the centre and the periphery, fuelled secessionism as a radical shift of the institutional setup. Nevertheless, other researchers have remarked that a recession may enhance the status quo bias and decrease the likelihood of changes. Our paper aims at contributing to this debate by analysing the case of Catalonia. We use an aggregate and an individual-level empirical design to explore the relationship between the deterioration of the economic situation and the increase of preferences for secession among the Catalan population. The findings from the analysis of our empirical models do not support the hypothesis that the effects of the Great Recession had any significant impact on political preferences in Catalonia.  相似文献   

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前期以氯霉素乙酰转移酶(CAT)活性为指标的研究证明了,马立克氏病病毒(Marek’s disease virus,MDV)的pp38和pp24的同时表达可显著增强基因组中pp38基因与1.8kb mRNA转录子之间双向启动子的转录活性.本研究又以增强型绿色荧光蛋白(EGFP)表达水平作为pp38基因上游双向启动转录活性的标志,更直观地证明了只有当同一细胞内同时表达pp38和pp24时,该启动子活性才有完整的启动活性.为了证明这两个蛋白能否相结合,分别以单独表达pp38或pp24的重组质粒pcDNA-pp38或pcDNA-pp24及能同时表达这两个基因的重组质粒pBud-pp38-pp24质粒转染鸡胚成纤维细胞(CEF),用pp38特异的单克隆抗体H19对转染细胞的裂解标记物进行免疫沉淀实验.结果表明,H19可沉淀pp38,但pp24只是在pp38同时存在时才被H19沉淀,而在pcDNA-pp24单独转染的处理样品中不能显示pp24的条带.这证明了,pp24是通过与pp38的结合而被共沉淀下来的,显示pp24和pp38在天然状态下可以形成异二聚体或多聚体.上述两个独立的实验结果表明,pp38和pp24是以聚合体的形式结合于该双向启动子发挥作用的.  相似文献   

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1. Feeding of alpha-p-chlorophenoxyisobutyrate (CPIB) to rats increased ubiquinone concentration in the liver but not in other tissues. The increase was progressive with the time of feeding and related to the concentration of CPIB in the diet. 2. Incorporation of [1-(14)C]acetate, but not of [2-(14)C]mevalonate, into sterols in the liver in vivo or by liver slices in vitro was decreased on feeding the rats with CPIB. However, incorporation of mevalonate into ubiquinone increased. 3. CPIB, when added in low concentrations to liver slices, had no effect on isoprene synthesis from acetate; higher concentrations, however, were inhibitory. 4. No activation of ubiquinone synthesis from mevalonate was observed when CPIB was added to the liver slices synthesizing ubiquinone. 5. The increase in ubiquinone in CPIB-fed animals appears to be due to increased synthesis in the initial stages and to decreased catabolism in the later stages. 6. An inverse relationship was found between the concentration of ubiquinone in the liver and the serum sterol concentration in CPIB-fed rats.  相似文献   

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1. Starvation for 3 days produces a decrease in methaemoglobin-reductase and glutathione-reductase activities, but it does not alter the glucose 6-phosphate-dehydrogenase activity of the rat erythrocyte. 2. The feeding of a protein-free diet for 11 days causes greater changes in the first two enzymes and also a diminution of the third. Under this experimental condition slight decreases in protein and haemoglobin contents were noted. 3. The experimental animals did not show methaemoglobinaemia, probably because the activity of methaemoglobin diaphorase is preserved. 4. The GSH content was not affected but the stability of the tripeptide in the presence of an oxidizing agent was diminished.  相似文献   

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