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161.
Allison M Churcher Jose Martin Pujolar Massimo Milan Peter C Hubbard Rute ST Martins Jo?o L Saraiva Mar Huertas Luca Bargelloni Tomaso Patarnello Ilaria AM Marino Lorenzo Zane Adelino VM Canário 《BMC genomics》2014,15(1)
Background
The vertebrate brain plays a critical role in the regulation of sexual maturation and reproduction by integrating environmental information with developmental and endocrine status. The European eel Anguilla anguilla is an important species in which to better understand the neuroendocrine factors that control reproduction because it is an endangered species, has a complex life cycle that includes two extreme long distance migrations with both freshwater and seawater stages and because it occupies a key position within the teleost phylogeny. At present, mature eels have never been caught in the wild and little is known about most aspects of reproduction in A. anguilla. The goal of this study was to identify genes that may be involved in sexual maturation in experimentally matured eels. For this, we used microarrays to compare the gene expression profiles of sexually mature to immature males.Results
Using a false discovery rate of 0.05, a total of 1,497 differentially expressed genes were identified. Of this set, 991 were expressed at higher levels in brains (forebrain and midbrain) of mature males while 506 were expressed at lower levels relative to brains of immature males. The set of up-regulated genes includes genes involved in neuroendocrine processes, cell-cell signaling, neurogenesis and development. Interestingly, while genes involved in immune system function were down-regulated in the brains of mature males, changes in the expression levels of several receptors and channels were observed suggesting that some rewiring is occurring in the brain at sexual maturity.Conclusions
This study shows that the brains of eels undergo major changes at the molecular level at sexual maturity that may include re-organization at the cellular level. Here, we have defined a set of genes that help to understand the molecular mechanisms controlling reproduction in eels. Some of these genes have previously described functions while many others have roles that have yet to be characterized in a reproductive context. Since most of the genes examined here have orthologs in other vertebrates, the results of this study will contribute to the body of knowledge concerning reproduction in vertebrates as well as to an improved understanding of eel biology.Electronic supplementary material
The online version of this article (doi:10.1186/1471-2164-15-799) contains supplementary material, which is available to authorized users. 相似文献162.
JENNIFER L. APPLE TONY GRACE ANTHONY JOERN PAUL ST. AMAND SAMANTHA M. WISELY 《Molecular ecology》2010,19(18):4012-4028
In this study, we used a comparative genome scan to examine patterns of population differentiation with respect to host plant use in Hesperotettix viridis, a Nearctic oligophagous grasshopper locally specialized on various Asteraceae including Solidago, Gutierrezia, and Ericameria. We identified amplified fragment length polymorphism (AFLP) loci with significantly elevated FST (outlier loci) in multiple different‐host and same‐host comparisons of populations while controlling for geographic distance. By comparing the number and identities of outlier loci in different‐host vs. same‐host comparisons, we found evidence of host plant‐related divergent selection for some population comparisons (Solidago‐ vs. Gutierrezia‐feeders), while other comparisons (Ericameria‐ vs. Gutierrezia‐feeders) failed to demonstrate a strong role for host association in population differentiation. In comparisons of Solidago‐ vs. Gutierrezia‐feeding populations, a relatively high number of outlier loci observed repeatedly in different‐host comparisons (35% of all outliers and 2.7% of all 625 AFLP loci) indicated a significant role for host‐related selection in contributing to overall genomic differentiation in this grasshopper. Mitochondrial DNA sequence data revealed a star‐shaped phylogeny with no host‐ or geography‐related structure, low nucleotide diversity, and high haplotype diversity, suggesting a recent population expansion. mtDNA data do not suggest a long period of isolation in separate glacial refugia but are instead more compatible with a single glacial refugium and more recent divergence in host use. Our study adds to research documenting heterogeneity in differentiation across the genome as a consequence of divergent natural selection, a phenomenon that may occur as part of the process of ecological speciation. 相似文献
163.
Formation of 9-nm filaments from pilin monomers obtained by octyl-glucoside dissociation of Pseudomonas aeruginosa pili 总被引:8,自引:1,他引:7
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Pili isolated from Pseudomonas aeruginosa PAK were solubilized in the detergent octyl-glucoside. Subsequent removal of the detergent by dialysis resulted in the formation of short rods of about 9 nm in diameter and various lengths. The aggregation process was followed by ultracentrifugation, viscometry, and electron microscopy to show that the aggregates produced in this way are distinct from pili produced by the bacteria, both in diameter, as measured by electron micrographs, and in their inability to compete in a biological assay for pili. 相似文献
164.
165.
Using 240 pony mares, lighting regimens were tested for their efficiency in hastening the onset of the ovulatory season. The mean number of days from January 1 to first ovulation was used as the end point. No advantage was gained by beginning a fixed lighting regimen (, hours light/hours dark) November 1 (66 ±8) versus December 1 (65 ±9), but beginning on January 1 was less efficient (98 ±8; controls, 132 ±5; P<0.05). In another experiment, daily three-hour interruptions of either the light phase (67 ±10) or the dark phase (71 ±11) did not significantly retard the effectiveness of a fixed regimen of (54 ±5; controls, 142 ±6). A regimen every other day (natural day length on alternate days) resulted in an interval (85 ±7) that was shorter (P<0.05) than for the controls and longer (not significant) than for the daily regimen. When used with natural day length, a one-hour pulse of light in the evening (15 hours after sunrise) was not effective (141 ±6); a one-hour pulse in the morning 9.5 hours after sunset) was only partially effective (117 ±6). In another experiment, the interval was reduced (P<0.05) in a group with one hour of light fixed at 4:00 a.m. with natural day length (85 ±8; , 75 ±7; controls, 126 ±9). Results indicated that a fixed one-hour pulse of light at 4 a.m., used with natural day length, may provide an acceptable level of stimulation. 相似文献
166.
The structure of calcitonin isolated from salmon1 (SCT 1) has been recently established2 and confirmed by synthesis8. It possesses an exceptionally high level of activity, exhibiting about 20–50 times the hypocalcaemic potency of any other calcitonin isolated from mammalian species. 相似文献
167.
Two recombinant DNA plasmids coding for Drosophila tRNA3bVal hybridize to two different loci on the Drosophila genome. Plasmid pDt41R hybridizes at the 90BC site, and pDt78R hybridizes at the 84D site. Heteroduplexes of the two plasmids were examined by electron microscopy. The study shows that the Drosophila segments have significant homology only over the length of the tRNA3bVal genes. 相似文献
168.
169.
Hatching of the winter eggs of the fruit-tree red spider mite (Panonychus ulmi (Koch)) 总被引:2,自引:0,他引:2
W. I. ST G. LIGHT MARGARET E. JOHN H. J. GOULD K. J. COGHILL 《The Annals of applied biology》1968,62(2):227-239
Observations on the hatching of winter eggs of Panonychus ulmi (Koch) from apple orchards in England over the 5 years 1962-6 are described. Differences of 2–3 weeks between orchards in the date at which 50% hatch was reached were quite common and this was out of step with petal fall in the majority of orchards. There was a continuous range between early and late hatching populations and a tendency for the populations to hatch in the same order every year. In 1966 populations on Cox's Orange Pippin hatched earlier than those on Worcester Pearmain but the difference was unlikely to be of practical importance. Neither recording accumulated day degrees for populations hatched out-of-doors nor hatching in an incubator after chilling was considered to give a sufficiently reliable forecast of 50% hatch but observations in 1966 suggested that this might be predicted from the total eggs hatched in an incubator expressed as a percentage of total healthy eggs. 相似文献
170.
HAROLD ST. JOHN F.L.S. 《Botanical journal of the Linnean Society. Linnean Society of London》1969,62(2):187-204
The Hawaiian genus Brighamia (Lobeliaceae) was published in 1868 as monotypic, and it long remained so, even though it occurs on four islandS. It is a spectacular herb with a simple, thickened, fleshy, stem 1–5 m tall, with the leaves terminal and crowded, and subtended by them are the fragrant, salver-shaped flowers 12–15 cm in length. Further explorations have revealed new localities, mostly on the cliff faces of the windward sides of the islands. The present investigation has revealed significant differential characters in the calyx lobes, the flower colour, the hairiness of the filament tube and the anther connective, and the nature of the seed testa. Hence, the following new taxa are described: B.citrina var. napaliensis, B.rockii and B.rockii forma longiloba and B.remyi. 相似文献