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61.
Assessing the alignment of sexual and natural selection using radiomutagenized seed beetles 下载免费PDF全文
A major unsolved question in evolutionary biology concerns the relationship between natural and sexual selection. Sexual selection might augment natural selection, for example if mutations that harm female fecundity also reduce male mating success. Conversely, sexual selection might favour traits that impair naturally selected fitness components. We induced detrimental mutations in Callosobruchus maculatus beetles using X‐ray irradiation and then experimentally measured the effect of precopulatory sexual selection on offspring number and survival rate. Sexual selection treatment had a negative effect on egg‐to‐adult survivorship, although the number of progeny reaching adulthood was unaffected, perhaps because eggs and juveniles that failed to develop lessened competition on the survivors. We hypothesize that the negative effect of sexual selection arose because sexually competitive males transmitted a smaller nuptial gift or carried alleles that conferred reduced survival. Although we found no evidence that sexual selection on males can purge alleles that are detrimental to naturally selected fitness components, such benefits might exist in other environmental or genetic contexts. 相似文献
62.
Alethia A. Hostetter Michelle L. Miranda Victoria J. DeRose Karen L. McFarlane Holman 《Journal of biological inorganic chemistry》2011,16(8):1177-1185
[ImH][trans-RuIIICl4(DMSO)(Im)] (where DMSO is dimethyl sulfoxide and Im is imidazole) (NAMI-A) is an antimetastatic prodrug currently in phase
II clinical trials. The mechanisms of action of this and related Ru-based anticancer agents are not well understood, but several
cellular targets have been suggested. Although Ru has been observed to bind to DNA following in vitro NAMI-A exposure, little
is known about Ru–DNA interactions in vivo and even less is known about how this or related metallodrugs might influence cellular
RNA. In this study, Ru accumulation in cellular RNA was measured following treatment of Saccharomyces cerevisiae with NAMI-A. Drug-dependent growth and cell viability indicate relatively high tolerance, with approximately 40% cell death
occurring at 6 h for 450 μM NAMI-A. Significant dose-dependent accumulation of Ru in cellular RNA was observed by inductively coupled plasma mass spectrometry
measurements on RNA extracted from yeast treated with NAMI-A. In vitro, binding of Ru species to drug-treated model DNA and
RNA oligonucleotides at pH 6.0 and 7.4 was characterized by matrix-assisted laser desorption/ionization time-of-flight mass
spectrometry in the presence and absence of the reductant ascorbate. The extent of Ru–nucleotide interactions increases slightly
with lower pH and significantly in the presence of ascorbate, with differences in observed species distribution. Taken together,
these studies demonstrate the accumulation of aquated and reduced derivatives of NAMI-A on RNA in vitro and in cellulo, and
enhanced binding with nucleic acid targets in a tumorlike acidic, reducing environment. To our knowledge, this is also the
first study to characterize NAMI-A treatment of S. cerevisiae, a genetically tractable model organism. 相似文献
63.
Brownridge P Holman SW Gaskell SJ Grant CM Harman VM Hubbard SJ Lanthaler K Lawless C O'Cualain R Sims P Watkins R Beynon RJ 《Proteomics》2011,11(15):2957-2970
In this paper, we discuss the challenge of large-scale quantification of a proteome, referring to our programme that aims to define the absolute quantity, in copies per cell, of at least 4000 proteins in the yeast Saccharomyces cerevisiae. We have based our strategy on the well-established method of stable isotope dilution, generating isotopically labelled peptides using QconCAT technology, in which artificial genes, encoding concatenations of tryptic fragments as surrogate quantification standards, are designed, synthesised de novo and expressed in bacteria using stable isotopically enriched media. A known quantity of QconCAT is then co-digested with analyte proteins and the heavy:light isotopologues are analysed by mass spectrometry to yield absolute quantification. This workflow brings issues of optimal selection of quantotypic peptides, their assembly into QconCATs, expression, purification and deployment. 相似文献
64.
65.
肠道病毒71型作为引起儿童群体常见传染性手足口病(HFMD)的主要病原,具有导致少量感染个体出现脑炎等神经系统病变以及相关心肺功能衰竭的病理学特性.因此其预防性疫苗的研发具有重要的公共卫生意义.在前期工作的基础上,一种EV71灭活病毒疫苗(人二倍体细胞)在本研究中基于恒河猴婴猴模型进行了相应的免疫保护性分析.以160EU剂量对2~3月龄婴猴进行0,4周免疫后,动物在第4周接受了剂量为10。~CCID50的病毒经呼吸道的攻击.对病毒攻击后动物在14天内的临床症状、血液生物学、器官病原学分布以及病理学检测的动态观察表明,经疫苗免疫的动物未出现对照动物所具有的特征性临床表现,其血液生物学及病理学检测均无异常.同时,器官病原学分布亦呈阴性.结合动物中和抗体的明确增长及对照动物的综合表现分析,本文的工作证实了该EV71灭活病毒疫苗(人二倍体细胞)在恒河猴婴猴体内的免疫保护性. 相似文献
66.
Nodes in phylogenetic trees: the relation between imbalance and number of descendent species 总被引:1,自引:0,他引:1
Holman EW 《Systematic biology》2005,54(6):895-899
The imbalance of a node in a phylogenetic tree can be defined in terms of the relative numbers of species (or higher taxa) on the branches that originate at the node. Empirically, imbalance also turns out to depend on the absolute total number of species on the branches: in a sample of large trees, nodes with more descendent species tend to be more unbalanced. Subsidiary analyses suggest that this pattern is not a result of errors in tree estimation. Instead, the increase in imbalance with species is consistent with a cumulative effect of differences in diversification rates between branches. [Equal-rates Markov model; imbalance; phylogeny shape; proportional-to-distinguishable-arrangements model.]. 相似文献
67.
Cossío-Bayúgar R Miranda E Holman PJ 《Insect biochemistry and molecular biology》2005,35(12):1378-1387
Phospholipid-hydroperoxide glutathione peroxidase (PHGPx) enzymes are associated with cellular protection by the role they play in reducing hydroperoxides of phospholipids, thereby preventing membrane lipoperoxidation. As part of their toxic effect, some pesticides stimulate peroxidation of cellular membranes. We isolated and sequenced a PHGPx gene from the cattle tick Boophilus microplus that encodes a protein of 169 amino acids, including a TGA-encoded selenocysteine at residue 46 and active site residues Gln82 and Trp135 that interact with the selenocysteine. The motif that directs the insertion of selenocysteine at the opal codon is found in the 3′-untranslated region. PHGPx sequences from pesticide-resistant and susceptible B. microplus ticks show nucleotide differences at eight positions among the strains, with five resulting in amino acid substitutions in the deduced protein sequence. Two distinct PHGPx alleles were identified in an organophosphate-resistant tick strain. Real-time PCR quantification of gene expression revealed increased PHGPx in two strains resistant to a single acaricide class. Strains resistant to two or more classes showed a reduction in PHGPx. 相似文献
68.
Sadd B Holman L Armitage H Lock F Marland R Siva-Jothy MT 《Journal of evolutionary biology》2006,19(2):321-325
Organisms partition resources into life-history traits in order to maximise fitness over their expected lifespan. For the males of many species fitness is determined by qualitative and quantitative aspects of costly sexual signals: The notion that epigamic traits are costly forms the cornerstone of those theories that propose parasites drive sexual selection. Consequently studies examining this notion assume sexual signalling is honest (i.e. driven by cost) when they seek to identify correlations or causal links between male immune function and attractiveness. We demonstrate that immune challenged males of the mealworm beetle, Tenebrio molitor, increased their investment in epigamic pheromone signals: these males became significantly more attractive to females whilst increasing the activity of a key immune effector system. In other words males increase terminal reproductive effort (invest in attractiveness) in response to a survival threat (immune insult). Consequently the signal preferred by the female is dishonest when considering the male's condition. 相似文献
69.
T. NGAMSIRI Y. OHASHI N. SUKUMASAVIN M. NAKAJIMA U. NA‐NAKORN N. TANIGUCHI 《Molecular ecology resources》2006,6(2):313-315
Microsatellite DNA markers for a critically endangered Mekong giant catfish (Pangasianodon gigas Roberts and Vidthayanon, 1991) were developed from fin clips collected from captive fish using (GT)15 probe. The number of alleles per locus ranged from two to four. The expected heterozygosities ranged from 0.13 to 0.68. Also, these primers were successfully amplified in four closely related species, Pangasius bocourti, Pangasius conchophilus, Pangasius larnaudii and Pangasius sanitwongsei with the number of alleles per locus ranged from 1 to 13, 1 to 16, 1 to 12 and 1 to 4, respectively. These markers should prove to be very useful for the evaluation of genetic diversity for this species and other related Pangasius species. 相似文献
70.