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11.
Margaret?O?Nwagwu Helen?Baines Jeffrey?B?Kerr Francis?JP?EblingEmail author 《Reproductive biology and endocrinology : RB&E》2005,3(1):48
Background
Testicular development is arrested in the hypogonadal (hpg) mouse due to a congenital deficiency in hypothalamic gonadotropin-releasing hormone (GnRH) synthesis. Chronic treatment of male hpg mice with estradiol induces FSH synthesis and secretion, and causes testicular maturation and qualitatively normal spermatogenesis. As estradiol negative feedback normally inhibits FSH production in the male, this study tested whether this paradoxical response to estradiol in the male hpg mouse might be due to inadequate masculinisation or incomplete defeminization in the neonatal period. Previous studies have demonstrated that treatment of hpg mice with testosterone propionate in the immediate neonatal period is necessary to allow full reproductive behaviors to be expressed following suitable endocrine stimulation at adult ages. 相似文献12.
13.
Amiloride does not alter NaCl avoidance in Fischer-344 rats 总被引:2,自引:2,他引:0
Fischer-344 (F-344) rats differ from other common rat strains in that they
fail to show any preference for NaCl at any concentration in two- bottle
preference tests. Because 100 microM amiloride partially blocks the
NaCl-evoked chorda tympani (CT) response in electrophysiological studies,
we tested NaCl preference (0.068-0.273 M) in F-344 rats with and without
100 microM amiloride solution as the solvent. A third group was tested with
unadulterated NaCl solutions following CT transection. Amiloride had no
significant effect on the NaCl preference-aversion function, whereas CT
transection significantly reduced NaCl avoidance. These results suggest
that the amiloride-sensitive component of the NaCl response is not
necessary for F-344 rats to display avoidance of NaCl, but the entire CT
input is.
相似文献
14.
Cassava is infected by numerous geminiviruses in Africa and India that cause devastating losses to poor farmers. We here describe the molecular diversity of seven representative cassava mosaic geminiviruses (CMGs) infecting cassava from multiple locations in Tanzania. We report for the first time the presence of two isolates in East Africa: (EACMCV-[TZ1] and EACMCV-[TZ7]) of the species East African cassava mosaic Cameroon virus, originally described in West Africa. The complete nucleotide sequence of EACMCV-[TZ1] DNA-A and DNA-B components shared a high overall sequence identity to EACMCV-[CM] components (92% and 84%). The EACMCV-[TZ1] and -[TZ7] genomic components have recombinations in the same genome regions reported in EACMCV-[CM], but they also have additional recombinations in both components. Evidence from sequence analysis suggests that the two strains have the same ancient origin and are not recent introductions. EACMCV-[TZ1] occurred widely in the southern part of the country. Four other CMG isolates were identified: two were close to the EACMV-Kenya strain (named EACMV-[KE/TZT] and EACMV-[KE/TZM] with 96% sequence identity); one isolate, TZ10, had 98% homology to EACMV-UG2Svr and was named EACMV-UG2 [TZ10]; and finally one isolate was 95% identical to EACMV-[TZ] and named EACMV-[TZ/YV]. One isolate of African cassava mosaic virus with 97% sequence identity with other isolates of ACMV was named ACMV-[TZ]. It represents the first ACMV isolate from Tanzania to be sequenced. The molecular variability of CMGs was also evaluated using partial B component nucleotide sequences of 13 EACMV isolates from Tanzania. Using the sequences of all CMGs currently available, we have shown the presence of a number of putative recombination fragments that are more prominent in all components of EACMV than in ACMV. This new knowledge about the molecular CMG diversity in East Africa, and in Tanzania in particular, has led us to hypothesize about the probable importance of this part of Africa as a source of diversity and evolutionary change both during the early stages of the relationship between CMGs and cassava and in more recent times. The existence of multiple CMG isolates with high DNA genome diversity in Tanzania and the molecular forces behind this diversity pose a threat to cassava production throughout the African continent. 相似文献
15.
Celine Scornavacca Vincent Berry Vincent Lefort Emmanuel JP Douzery Vincent Ranwez 《BMC bioinformatics》2008,9(1):413
Background
Supertree methods combine phylogenies with overlapping sets of taxa into a larger one. Topological conflicts frequently arise among source trees for methodological or biological reasons, such as long branch attraction, lateral gene transfers, gene duplication/loss or deep gene coalescence. When topological conflicts occur among source trees, liberal methods infer supertrees containing the most frequent alternative, while veto methods infer supertrees not contradicting any source tree, i.e. discard all conflicting resolutions. When the source trees host a significant number of topological conflicts or have a small taxon overlap, supertree methods of both kinds can propose poorly resolved, hence uninformative, supertrees. 相似文献16.
Helen Baines Margaret O Nwagwu Graham R Hastie Roman A Wiles Terry M Mayhew Francis JP Ebling 《Reproductive biology and endocrinology : RB&E》2008,6(1):4
Background
The hypogonadal (hpg) mouse is widely used as an animal model with which to investigate the endocrine regulation of spermatogenesis. Chronic treatment of these GnRH-deficient mice with estradiol is known to induce testicular maturation and restore qualitatively normal spermatogenesis. The aim of the current studies was to investigate whether these effects of estradiol are direct effects in the testis, or indirect actions via paradoxical stimulation of FSH secretion from the pituitary gland. 相似文献17.
J Klein J Gonzalez J Duchene L Esposito JP Pradère E Neau C Delage D Calise A Ahluwalia P Carayon JB Pesquero M Bader JP Schanstra JL Bascands 《FASEB journal》2009,23(1):134-142
Renal fibrosis is the common histological feature of advanced glomerular and tubulointerstitial disease leading to end-stage renal disease (ESRD). However, specific antifibrotic therapies to slow down the evolution to ESRD are still absent. Because persistent inflammation is a key event in the development of fibrosis, we hypothesized that the proinflammatory kinin B1 receptor (B1R) could be such a new target. Here we show that, in the unilateral ureteral obstruction model of renal fibrosis, the B1R is overexpressed and that delayed treatment with an orally active nonpeptide B1R antagonist blocks macrophage infiltration, leading to a reversal of the level of renal fibrosis. In vivo bone marrow transplantation studies as well as in vitro studies on renal cells show that part of this antifibrotic mechanism of B1R blockade involves a direct effect on resident renal cells by inhibiting chemokine CCL2 and CCL7 expression. These findings suggest that blocking the B1R is a promising antifibrotic therapy. 相似文献
18.
Lindström Irene Bontell Neil Hall Kevin E Ashelford JP Dubey Jon P Boyle Johan Lindh Judith E Smith 《Genome biology》2009,10(5):R53-17
Background
Toxoplasma gondii is a zoonotic parasite of global importance. In common with many protozoan parasites it has the capacity for sexual recombination, but current evidence suggests this is rarely employed. The global population structure is dominated by a small number of clonal genotypes, which exhibit biallelic variation and limited intralineage divergence. Little is known of the genotypes present in Africa despite the importance of AIDS-associated toxoplasmosis. 相似文献19.
Roger L. Vallejo Yniv Palti Sixin Liu Jason P. Evenhuis Guangtu Gao Caird E. Rexroad III Gregory D. Wiens 《Marine biotechnology (New York, N.Y.)》2014,16(3):349-360
Bacterial cold water disease (BCWD) causes significant economic loss in salmonid aquaculture. We previously detected genetic variation in survival following challenge with Flavobacterium psychrophilum (Fp), the causative agent of BCWD in rainbow trout (Oncorhynchus mykiss). A family-based selection program to improve resistance was initiated in 2005 at the USDA National Center for Cool and Cold Water Aquaculture. Select crosses were made in 2007 and 2009 to evaluate family-based disease survival using Fp injection challenges. From each putative F2/BC1 family generated in 2009, 200–260 fish were challenged in 4–7 replicates per family. Whole genome QTL scans of three F2/BC1 families were conducted with about 270 informative microsatellite loci per family spaced at an average interval size of 6 cM throughout the rainbow trout genome. Markers on chromosomes containing QTL were further evaluated in three additional F2/BC1 families. The additional F2/BC1 families were sire or dam half-sibs (HS) of the initially genome scanned families. Overall, we identified nine major QTL on seven chromosomes that were significant or highly significant with moderate to large effects of at least 13 % of the total phenotypic variance. The largest effect QTL for BCWD resistance explaining up to 40 % of the phenotypic variance was detected on chromosome OMY8 in family 2009070 and in the combined dam HS family 2009069–070. The nine major QTL identified in this study are candidates for fine mapping to identify new markers that are tightly linked to disease resistance loci for using in marker assisted selection strategies. 相似文献
20.
Eight species of the Strongylophthalmyiidae are reported from Papua New Guinea. Of these, five species (Strongylophthalmyia gigantica sp. nov., S. papuana sp. nov., S. rubella sp. nov., S. sedlaceki sp. nov. and S. shatalkini sp. nov.) are described as new to science. Strongylophthalmyia puncticollis Frey is recorded for the first time from Papua New Guinea. Faunistic remarks, a key to the species of the Strongylophthalmyia in Papua New Guinea and a world checklist are provided. 相似文献