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To clarify the role of avian Pasteurella multocida capsule in pathogenesis, adhesion of capsulated strains P-1059, X-73 and Pm-18, and noncapsulated strains P-1059B, Pm-1 and Pm-3 to chicken embryo fibroblast (CEF) cells was compared. Number of adherent organisms of the capsulated strains to CEF cells were approximately three times as much as noncapsulated strains indicating that adhesive properties were enhanced by the presence of bacterial capsule. Pretreatments of the bacterial cells with heat, trypsin, or with antiserum caused a marked decrease in adhesion of capsulated strain P-1059 and its noncapsulated variant P-1059B. However, depolymerization of capsular hyaluronic acid with high dose of hyaluronidase enhanced adhesion of these strains. Combined treatments of the bacterial cells with both hyaluronidase and trypsin significantly (P < 0.05) inhibited the adherence of strain P-1059 as compared to the treatment only with trypsin, but strain P-1059B was not affected. SDS-PAGE profiles of crude capsular extract (CCE) prepared from capsulated strain P-1059 and its noncapsulated variant P-1059B grown on dextrose starch agar (DSA) plates by heating at 56 degrees C in a 2.5% NaCl solution demonstrated eight protein bands of 28, 34, 36, 39, 52, 56, 63 and 93 kDa. The 28, 34 and 36 kDa proteins were commonly major for both strains, and the 39 kDa protein was major only for strain P-1059 but poor in strain P-1059B. Outer membrane protein (OMP) profiles were identical with a major protein at 34 kDa and four minor proteins between the two strains. The adhesion of strain P-1059 and strain P-1059B to CEF cells was inhibited significantly (P < 0.01) by treatment with rabbit antisera against P-1059, P-1059B, CCE or 39 kDa protein of strain P-1059 as compared to the treatment with either PBS or with normal rabbit serum. These results indicated that an antigenic 39 kDa protein in the capsule may be responsible for adhesion of avian P. multocida type A strains to CEF cells as a virulence factor.  相似文献   
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The inwardly rectifying K+ channels, Kir1.1, Kir2.3 and Kir4.1-Kir5.1, are the candidate chemosensory molecules for CO2/H+. We determined the mRNA expression and immunohistochemical localization of these channels in the medulla oblongata of the rat. RT-PCR analysis revealed mRNAs of Kir1.1, Kir2.3, Kir4.1 and Kir5.1 were detected in the medulla. The immunoreactivities for Kir1.1, Kir2.3, Kir4.1, and Kir5.1 were observed in the medulla, and immunolabeling pattern was varied by the subunit. Immunoreactivities for Kir1.1 and Kir2.3 were observed in the nerve cell bodies and glial cells both in the chemosensory areas [nucleus tractus solitarius (NTS), nucleus raphe obscurus (RO), pre-B?tzinger complex (PreB?tC)] and non-chemosensory area [hypoglossal nucleus (XII), inferior olive nucleus (IO)]. Kir4.1 immunoreactivity was observed in the glial cells and neuropil, especially in XII and IO. Kir5.1 immunoreactivity was observed in the nerve cell bodies in the XII, RO, and PreB?tC, but not in the NTS or IO. In the NTS, a dense network of varicose nerve fibers showed immunoreactivity for Kir5.1. Our findings suggest that Kir channels may not act specific to the central chemoreception, but regulate the ionic properties of cellular membranes in various neurons and glial cells.  相似文献   
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Functional relationship between nuclear receptor subfamily 4 group A member 3 (Nr4a3) and annexin A5 (Anxa5), which are two gonadotropin-releasing hormone (GnRH)-inducible genes, has been established while evaluating pituitary gonadotropes in relation to follicle-stimulating hormone beta (Fshb) expression. However, the physiological variations that arise due to the differential expression of these genes in the pituitary gland during rat estrous cycle remain unknown. This study aimed to evaluate the Nr4a3 and Anxa5 mRNA expression during the estrous cycle in rats in comparison with the expression of the gonadotropin subunit genes, luteinizing hormone beta (Lhb) and Fshb. Nr4a3 mRNA expression showed a single peak at 1400 h of proestrus during the 4-d estrous cycle. Anxa5 mRNA level was elevated along with increased Fshb mRNA expression after the decline of Nr4a3 mRNA until 2300 h. Lhb mRNA expression levels were not significantly changed during the estrous cycle. Notably, addition of a GnRH antagonist at 1100 h completely eradicated luteinizing hormone secretion at 1400 h and 1700 h of proestrus, and significantly reduced the Nr4a3 mRNA expression level at both the time points. These results suggest that GnRH is, at least partly, responsible for the increase in pituitary Nr4a3, and that the interaction between NR4A3 and ANXA5 is required to regulate Fshb expression during the preovulatory gonadotropin surge.  相似文献   
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ABSTRACT A genetic cross was performed between a Setaria isolate (pathogenic on foxtail millet) and a Triticum isolate (pathogenic on wheat) of Magnaporthe grisea to elucidate genetic mechanisms of its specific parasitism toward wheat. A total of 80 F(1) progenies were obtained from 10 mature asci containing 8 ascospores. Lesions on wheat leaves produced by the F(1) progenies were classified into four types, which segregated in a 1:1:1:1 ratio. This result suggested that the pathogenicity of the F(1) population on wheat was controlled by two genes located at different loci. This idea was supported by backcross analyses. We designated these loci as Pwt1 and Pwt2. Cytological analyses revealed that Pwt1 and Pwt2 were mainly associated with the hypersensitive reaction and papilla formation, respectively.  相似文献   
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Antioxidants such as vitamin C, vitamin E, and carotenoids have been reported to prevent the progression of experimentally induced cataracts. However, little is known of the effect of procyanidins, a powerful antioxidant, on cataract formation. This paper investigates the anticataract activity of grape seed extract (GSE, which contains 38.5% procyanidins) in hereditary cataractous rats (ICR/f rats). The ICR/f rats were fed a standard diet containing 0 or 0.213% GSE [0.082% procyanidins in the diet (w/w)] for 27 days. The GSE significantly prevented and postponed development of cataract formation by evaluation of slit lamp observations of the rats' eyes. Lens weight and malondialdehyde concentration in the lens and plasma cholesteryl ester hydroperoxide (ChE-OOH) level induced by CuSO4 were significantly lower in the GSE group compared with the control group. The rats were also fed for 14 days either the diet containing 0.085% procyanidin dimer to tetramer fraction (0.085% as the procyanidins), the diet containing 0.090% procyanidin pentamer to heptamer fraction (0.085% as the procyanidins), or the diet containing 0.093% procyanidin oligomers more than decamer fraction (0.085% as the procyanidins). The ChE-OOH levels in the procyanidin pentamer to heptamer and procyanidin oligomers more than decamer groups were significantly lower than in the procyanidin dimer to tetramer group. These results suggested that procyanidins and their antioxidative metabolites prevented the progression of cataract formation by their antioxidative action. The larger molecular procyanidins in the GSE might contribute this anticataract activity.  相似文献   
38.
In Mongolia, yak (Bos grunniens) are able to live in alpine areas and their products greatly influence the lives of the local people. Increased vigour in hybridized yak and cattle can offer benefits for livestock farmers. However, male hybrids show reproductive defects resulting from spermatogenesis arrest, affecting the conservation and maintenance of dominant traits in the next generation. The underlying mechanisms involved in hybrid cattle–yak infertility have recently been investigated; however, the genetic cause is still unclear. Androgens and androgen receptor (AR) signalling are required for spermatogenesis. We, therefore, evaluated the expression of AR, 3β-hydroxysteroid dehydrogenase (3βHSD) and 5α-reductase 2 (SRD5A2) in Leydig cells to investigate their function in cattle–yak spermatogenesis. Testicular tissues from yaks (1–3 years old) and hybrids (F1–F3, 2 years old) were collected and subjected to immunohistochemistry and image analyses to investigate the expression of each parameter in the Leydig cells. After maturation at 2 years, the expression levels of AR increased and the levels of 3βHSD decreased, but the SRD5A2 levels remained constant in yak. However, the cattle–yak hybrid F2 showed immature testicular development and significantly different expression levels of AR and 3βHSD compared with mature yak. These results suggest that the decreased expression of AR and increased expression of 3βHSD in the Leydig cells of cattle–yak hybrid testes may represent one of the causes of infertility. Our study might help in solving the problem of infertility in crossbreeding.  相似文献   
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A subcutaneous tumor was found in the right abdomen of a 16-week-old male TCRβ and p53 double-knockout mouse. The tumor had indistinct borders with the surrounding tissue. The cut surface after formalin fixation was pale yellowish white, partially dark red and partly white. Histologically, the tumor was composed of three distinct regions. The first region showed pleomorphic cells arranged in sheets. The second region showed spindle cells arranged in interlacing fascicles. The final region contained a mixture of the above mentioned two types of cells. Furthermore, a small amount of collagen fibers, round cells, multinucleated giant cells, and cells with eosinophilic granules were observed between these tumor cells. Immunohistochemical examination and electron microscopy identified that the pleomorphic cells and spindle cells were histiocytes and fibroblasts, respectively, and that the round cells were undifferentiated mesenchymal cells. Based on these findings, the tumor was diagnosed as a malignant fibrous histiocytoma.  相似文献   
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