A limited role for SsrA/B in persistent Salmonella Typhimurium infections in pigs     

Boyen F  Pasmans F  Van Immerseel F  Morgan E  Botteldoorn N  Heyndrickx M  Volf J  Favoreel H  Hernalsteens JP  Ducatelle R  Haesebrouck F 《Veterinary microbiology》2008,128(3-4):364-373

Virulence genes regulated by the SsrA/B system are indispensable for systemic disease in BALB/c mice. The role of this regulating system in the pathogenesis of Salmonella Typhimurium infections in pigs is not documented. In the present study, the interactions of Salmonella Typhimurium and an ssrA/B mutant were compared in vitro and in vivo. The ssrA/B mutant strain displayed decreased Salmonella Pathogenicity Island 2 (SPI-2) expression levels, showed a replication defect in mouse macrophages and was attenuated in a mouse model after oral inoculation. Using real time qRT-PCR and a porcine ileal loop model, it was shown that the ssrA/B mutant strain was not significantly attenuated in overall virulence and SPI-1 expression in specific. Flowcytometric analysis demonstrated that the ssrA/B mutant strain was defective in intracellular replication in porcine macrophages. After oral inoculation of piglets with the wild type strain or the ssrA/B mutant strain, the animals of both groups excreted Salmonella and were colonized by Salmonella to the same extent. In an intravenous mixed infection model, the ssrA/B mutant strain was defective in the colonization of several internal organs. These results suggest that the ssrA/B gene of Salmonella Typhimurium plays a limited role in the persistent intestinal colonization of pigs.  相似文献   

内蒙古阿拉善盟双峰驼驼乳理化性质研究   总被引：2，自引：0，他引：2  

赵电波  吉日木图  刘红霞  邵亚东  张和平 《乳业科学与技术》2005,27(3):112-117

本文研究了10峰内蒙古阿拉善盟双峰驼不同泌乳时间驼乳的一般理化性质。其比重及pH值与已有报道的单峰驼驼乳结果基本一致,而酸度(%)高于单峰驼。电导率与乳中Na+、K+和Cl-含量之和有关,随三者之和的增减而增减。驼乳的蛋白质、脂肪、乳糖、干物质、灰分和钙的含量均高于牛乳,磷的含量比牛乳略低。驼乳的缓冲性与牛乳有差异:当乳样先酸化后用碱回滴时,驼乳和牛乳分别在pH4.4～6.6和pH5.0～6.6范围内出现典型的“弧形线”,驼乳的最大缓冲作用发生在pH近似4.4处,牛乳的最大缓冲作用在pH近似5.1处,但驼乳在pH4.9处仍有一个缓冲峰。双峰驼驼乳的酒精稳定性(75±2.0)%稍低于牛乳的酒精稳定性(77±1.0)%,驼乳与牛乳的酒精稳定性的变化趋势基本一致,加入Na+、K+都引起酒精稳定性降低,游离Ca2+浓度的降低或pH值的上升都会导致酒精稳定性的增加。  相似文献   

Egg oxidation status,antioxidant enzyme activities,lipid classes,fatty acid composition profile and embryo survival rates during in vitro oocyte ageing in tench Tinca tinca (Linnaeus, 1758)          下载免费PDF全文

Azadeh Mohagheghi Samarin  Sabine Sampels  Anna Krzyskow  Viktoriia Burkina  Jiri Kristan  David Gela  Martin Flajshans  Tomas Policar  Azin Mohagheghi Samarin 《Aquaculture Research》2018,49(6):2305-2316

The effect of in vitro storage of oocytes on embryos survival rate, egg oxidation status, antioxidant enzyme activities, lipid classes and fatty acid composition profile was investigated in common tench Tinca tinca. In order to identify the role of oxidative stress in the progress of oocyte ageing the levels of thiobarbituric acid reactive substances (TBARS) and carbonyls as indicators of lipid and protein oxidation were measured and the activity of antioxidant enzymes were examined. Stripped ova from six females were stored in cell culture plates at 20°C for up to 10 hr post‐stripping (HPS). The stored ova were fertilized and the embryo survival rates were assessed. The results indicated that tench eggs could be successfully stored in vitro for 4 hr after stripping at 20°C. Superoxide dismutase enzyme activity increased at 6 HPS, whereas glutathione peroxidase and glutathione reductase activities decreased in oocytes during in vitro storage (p < .05) at 4 and 8 HPSs, respectively. The level of malondialdehyde did not show any significant changes during the progress of oocyte ageing. Carbonyls increased up to 2 HPS and thereafter decreased significantly. However, ova ageing did not affect the main lipid class composition and the fatty acid composition of the eggs. Lower quality eggs exhibited lower levels of cholesterol but higher levels of triacylglycerol.  相似文献   

Comparison of terrestrial laser scanning and X-ray scanning in measuring Scots pine (Pinus sylvestris L.) branch structure     

Jiri Pyörälä  Ville Kankare  Mikko Vastaranta  Juha Rikala  Markus Holopainen  Marketta Sipi 《Scandinavian Journal of Forest Research》2018,33(3):291-298

While X-ray scanning is increasingly used to measure the interior quality of logs, terrestrial laser scanning (TLS) could be used to collect information on external tree characteristics. As branches are one key indicator of wood quality, we compared TLS and X-ray scanning data in deriving whorl locations and each whorl’s maximum branch and knot diameters for 162 Scots pine (Pinus sylvestris L.) log sections. The mean number of identified whorls per tree was 37.25 and 22.93 using X-ray and TLS data, respectively. The lowest TLS-derived whorl in each sample tree was an average 5.56?m higher than that of the X-ray data. Whorl-to-whorl mean distances and the means of the maximum branch and knot diameters in a whorl measured for each sample tree using TLS and X-ray data had mean differences of ?0.12?m and ?6.5?mm, respectively. One of the most utilized wood quality indicators, tree-specific maximum knot diameter measured by X-ray, had no statistically significant difference to the tree-specific maximum branch diameter measured from the TLS point cloud. It appears challenging to directly derive comparative branch structure information using TLS and X-ray. However, some features that are extractable from TLS point clouds are potential wood quality indicators.  相似文献   

驼乳及其抗微生物因子的特性   总被引：3，自引：1，他引：3  

范洪波  哈斯苏荣  吉日木图 《畜牧与饲料科学》2006,27(1):37-40

驼乳是干旱和半干旱地区人们重要的食物来源之一。世界上有些国家的人民还用驼乳来治疗疾病。笔者对驼乳的营养成分进行了介绍。还重点对它的抗微生物因子（溶菌酶、乳铁蛋白和免疫球蛋白等）及其作用进行了全面的阐述。  相似文献   

大麦赤霉病抗性的亲子相关分析     

吴基日  刘宪虎  许明子  李艳茹 《延边大学农学学报》1996,(3)

在二棱大麦中赤霉病抗性很强的Ｒｕｓｓｉａ６号和六棱大麦中抗性很弱的ＨＥＳ４的杂交后代Ｆ２代的５６０个个体中，以随机抽出８０个个体所展开的Ｆ３—Ｆ５系统来分析赤霉病抗性的亲子相关．结果表明，随着世代的推进，系统内标准差逐渐变小，相关系数逐渐提高，到Ｆ５抗性分离逐渐稳定，Ｆ４个体和由这个个体所展开的Ｆ５系统平均值之间的相关系数为０．６７０，Ｆ４个体所在的系统平均值和Ｆ５系统的平均值之间的相关系数为０．７９０，系统之间的相关系数大于亲代个体和次代系统平均值之间的相关系数．  相似文献   

Combinatorial ShcA docking interactions support diversity in tissue morphogenesis     

Hardy WR  Li L  Wang Z  Sedy J  Fawcett J  Frank E  Kucera J  Pawson T 《Science (New York, N.Y.)》2007,317(5835):251-256

Changes in protein-protein interactions may allow polypeptides to perform unexpected regulatory functions. Mammalian ShcA docking proteins have amino-terminal phosphotyrosine (pTyr) binding (PTB) and carboxyl-terminal Src homology 2 (SH2) domains, which recognize specific pTyr sites on activated receptors, and a central region with two phosphorylated tyrosine-X-asparagine (pYXN) motifs (where X represents any amino acid) that each bind the growth factor receptor-bound protein 2 (Grb2) adaptor. Phylogenetic analysis indicates that ShcA may signal through both pYXN-dependent and -independent pathways. We show that, in mice, cardiomyocyte-expressed ShcA directs mid-gestational heart development by a PTB-dependent mechanism that does not require the pYXN motifs. In contrast, the pYXN motifs are required with PTB and SH2 domains in the same ShcA molecule for the formation of muscle spindles, skeletal muscle sensory organs that regulate motor behavior. Thus, combinatorial differences in ShcA docking interactions may yield multiple signaling mechanisms to support diversity in tissue morphogenesis.  相似文献   

Recent advances toward the sustainable management of invasive Xylosandrus ambrosia beetles     

Gugliuzzo  Antonio  Biedermann  Peter H. W.  Carrillo  Daniel  Castrillo  Louela A.  Egonyu  James P.  Gallego  Diego  Haddi  Khalid  Hulcr  Jiri  Jactel  Hervé  Kajimura  Hisashi  Kamata  Naoto  Meurisse  Nicolas  Li  You  Oliver  Jason B.  Ranger  Christopher M.  Rassati  Davide  Stelinski  Lukasz L.  Sutherland  Roanne  Tropea Garzia  Giovanna  Wright  Mark G.  Biondi  Antonio 《Journal of pest science》2021,94(3):615-637

We provide an overview of both traditional and innovative control tools for management of three Xylosandrus ambrosia beetles (Coleoptera: Curculionidae: Scolytinae), invasive species with a history of damage in forests, nurseries, orchards and urban areas. Xylosandrus compactus, X. crassiusculus and X. germanus are native to Asia, and currently established in several countries around the globe. Adult females bore galleries into the plant xylem inoculating mutualistic ambrosia fungi that serve as food source for the developing progeny. Tunneling activity results in chewed wood extrusion from entry holes, sap outflow, foliage wilting followed by canopy dieback, and branch and trunk necrosis. Maintaining plant health by reducing physiological stress is the first recommendation for long-term control. Baited traps, ethanol-treated bolts, trap logs and trap trees of selected species can be used to monitor Xylosandrus species. Conventional pest control methods are mostly ineffective against Xylosandrus beetles because of the pests’ broad host range and rapid spread. Due to challenges with conventional control, more innovative control approaches are being tested, such as the optimization of the push–pull strategy based on specific attractant and repellent combinations, or the use of insecticide-treated netting. Biological control based on the release of entomopathogenic and mycoparasitic fungi, as well as the use of antagonistic bacteria, has yielded promising results. However, these technologies still require validation in real field conditions. Overall, we suggest that management efforts should primarily focus on reducing plant stress and potentially be combined with a multi-faceted approach for controlling Xylosandrus damage.

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IncN plasmids carrying bla CTX-M-1 in Escherichia coli isolates on a dairy farm     

Dolejska M  Jurcickova Z  Literak I  Pokludova L  Bures J  Hera A  Kohoutova L  Smola J  Cizek A 《Veterinary microbiology》2011,149(3-4):513-516

The aim of the study was to compare the prevalence of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli bovine isolates on a conventional dairy cattle farm with high consumption of parenteral and intramammary cephalosporins (farm A) and on an organic dairy farm with no cephalosporin use (farm B). ESBL-producing E. coli were isolated from rectal swabs and milk filters by selective cultivation on MacConkey agar with cefotaxime (2mg/l). ESBL genes were identified by polymerase chain reaction (PCR) and sequencing, and the genetic diversity of the isolates was determined by XbaI pulsed field gel electrophoresis (PFGE). Conjugative transfer, incompatibility group, and restriction fragment length polymorphism (RFLP) profiles of the ESBL-carrying plasmids were studied. Higher prevalence (39%, n(rectal samples in cows)=309) of CTX-M-1-producing E. coli isolates was found on farm A compared to farm B (<1%, n(rectal samples in cows)=154; 0%, n(rectal samples in calves)=46). Using PFGE, the isolates from farm A were divided into nine pulsotypes. In all ESBL-positive isolates, the bla(CTX-M-1) gene was carried on 40 kb IncN conjugative plasmids of three related HincII restriction profiles. Horizontal gene transfer through transmission of IncN plasmids harboring bla(CTX-M-1) as well as clonal dissemination of a particular clone seems to be involved in dissemination of CTX-M-1-producing E. coli isolates in cows on the farm using cephalosporins in treating bacterial infections. The study demonstrates a possible role of cephalosporin use in the widespread occurrence of CTX-M-1-producing E. coli on the conventional dairy cattle farm compared to the organic farm.  相似文献   

Immune development in jejunal mucosa after colonization with selected commensal gut bacteria: a study in germ-free pigs   总被引：1，自引：0，他引：1  

Haverson K  Rehakova Z  Sinkora J  Sver L  Bailey M 《Veterinary immunology and immunopathology》2007,119(3-4):243-253

The immunological structure of the porcine jejunal lamina propria in germ-free piglets was compared with that of their counterparts associated with two strains of commensal Escherichia coli, A0 34/86 serotype O83:K24:H31 and the O86 E. coli strain, up to 20 days post-colonization. In the antigen-presenting compartment, both dendritic cells (DC) and cells expressing CD163, probably macrophages were investigated. In addition we also assessed the number of CD2+/CD3+ (T) cells. In contrast to some previous reports, we show a total lack of both DC and T cells for germ-free animals in the diffuse lymphoid tissue of villi and crypts of the jejunum. Association with either strain of commensal E. coli had a profound effect on the immune structure and resulted in extensive recruitment of DC to the lamina propria and of T cells to epithelium and lamina propria. The data suggest that the earliest immigrant cells were monocytes, which soon acquired the phenotype of mucosal DC. T cells migrated in at a slightly slower rate. Nevertheless, the response could be extremely rapid: within 3 days of colonization with O83, the magnitude of this response was comparable to that observed 20 days post-colonization.  相似文献