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31.
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Sex ratio theory has proved remarkably useful in testing theadaptive nature of animal behavior. A particularly productivearea in this respect is Hamilton's theory of local mate competition(LMC), which has been extended in numerous directions to includegreater biological realism, allowing more detailed tests inspecific organisms. We have presented one such extension, termedasymmetrical LMC, which occurs when egg laying by females ona patch is asynchronous, and emerging males do not disperse,resulting in the extent of LMC on a patch varying over time.Our aim here is to test whether the parasitoid wasp Nasoniavitripennis responds to variation in the degree of asymmetricalLMC. Specifically, we show that females adjust their offspringsex ratios in response to (1) variation in the amount of asynchronyin emergence between broods on a patch and (2) the number andproportion of previously parasitized hosts on the patch. Ourresults provide qualitative support for the predictions of theory,suggesting new levels of complexity in the sex ratio behaviorof this much-studied organism. However, our results do not alwaysprovide quantitative support for theory, suggesting furthercomplexities that must be clarified.  相似文献   
33.
For decades, the bio-duck sound has been recorded in the Southern Ocean, but the animal producing it has remained a mystery. Heard mainly during austral winter in the Southern Ocean, this ubiquitous sound has been recorded in Antarctic waters and contemporaneously off the Australian west coast. Here, we present conclusive evidence that the bio-duck sound is produced by Antarctic minke whales (Balaenoptera bonaerensis). We analysed data from multi-sensor acoustic recording tags that included intense bio-duck sounds as well as singular downsweeps that have previously been attributed to this species. This finding allows the interpretation of a wealth of long-term acoustic recordings for this previously acoustically concealed species, which will improve our understanding of the distribution, abundance and behaviour of Antarctic minke whales. This is critical information for a species that inhabits a difficult to access sea-ice environment that is changing rapidly in some regions and has been the subject of contentious lethal sampling efforts and ongoing international legal action.  相似文献   
34.
The mechanism of the binding of 2-(4'-hydroxyphenylazo)benzoic acid (HABA) to bovine serum albumin was studied by relaxation methods as well as the binding isotherm using gel chromatography. A single relaxation was observed over a wide range of HABA concentration except at the extremes of high concentration where another slow process was observed. The concentration dependence of the reciprocal relaxation time of the fast process decreased monotonically with increase in concentration of HABA at constant polymer concentration. The data were analyzed on the basis of Brown's domain structure model and were found to be consistent with a sequential binding mechanism. The azohydrazon tautomerism of HABA was identified with the intramolecular step of the complex. The activation parameters of the step, determined from the temperature dependence of the relaxation time of the fast process, showed that this step is rate limited by an enthalpy barrier in both forward and backward directions. Comparison of the activation parameters with those of other serum albumin-ligand systems suggests that there is an enthalpy-entropy compensation in the activation process of the intramolecular step with the compensation temperature at about 270 K; the enthalpy-entropy compensation is thought to be related to the hydrophobic nature of the ligand.  相似文献   
35.
The specificity of the collagenolytic enzyme from the fungus Entomophthora coronata toward some inhibitors and the B chain of oxidized insulin was investigated and compared to that of the bacterial collagenase from Achromobacter iophagus. The fungal enzyme was completely inhibited by diisopropylfluorophosphate, tosyl-l-lysine chloromethyl ketone, and tosyl-amino-2-phenylethyl chloromethyl ketone but not at all by ethylenediaminetetraacetate. This indicates that it is not a metalloenzyme like the bacterial Achromobacter collagenase. The B chain of insulin was not hydrolysed at all by the bacterial enzyme under conditions where extensive digestion was observed with the Entomophthora enzyme. The fungal enzyme cleaves preferentially the bonds Leu15-Tyr16andLeu11Val12 as determined by automatic sequencing; the secondary cleavages were identified by a systematic analysis of the digestion mixture; thus, the fungal collagenolytic enzyme from Entomophthora coronata differs both structurally and functionally from the bacterial Achromobacter collagenase.  相似文献   
36.
SYNOPSIS Catalase activity of Paramecium tetraurelia decreased during autogamy and recovered to normal 5 days later. Autogamy also caused changes in the ciliate's sensitivity to natural ionizing radiations—the decrease in cell growth rate previously described in shielded cultures did not occur when autogamous cells were used. Maximum effect of shielding was observed in 11-day-old postautogamous cells. the role of the catalase in the mechanism of natural irradiation effect is discussed.  相似文献   
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Abstract. 1. Recapture probabilities were analysed for individually marked black swallowtails, Papilio polyxenes F., and tiger swallowtails, P.glaucus L. (Lepidoptera: Papilionidae).
2. Recapture rates differed with sex and behaviour at time of capture for P.polyxenes , but not with age. For P.glaucus , only differences related to behaviour at time of capture were significant.
3. Black swallowtail males that were not physically restrained in identification had a recapture probability (73%) that was significantly higher than the 45% for males that were captured and handled. The higher rate was also exhibited by released, laboratory-reared males.
4. The capture effect was due to increased dispersal out of the areas and not to avoidance of capture or the capture site.  相似文献   
39.
Abstract The genes encoding the CryIVB and CryIVD crystal polypeptides of B. thuringiensis subsp. israelensis were cloned indepently on a stable shuttle vector, and transfered into B. sphaericus 2297. Recombinant cells expressed the B. thuringiensis toxins during sporulation and were shown to be toxic to Aedes aegypti fourth instar larvae, whereas the parental strain was not.  相似文献   
40.
Many studies have examined the association between the FABP2 (rs1799883) Ala54Thr gene polymorphism and type 2 diabetes mellitus risk (T2DM) in various populations, but their results have been inconsistent. To assess this relationship more precisely, A HuGE review and meta‐analysis were performed. The PubMed and CNKI database was searched for case‐control studies published up to April 2014. Data were extracted and pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated. Ultimately, 13 studies, comprising 2020 T2DM cases and 2910 controls were included. Overall, for the Thr carriers (Ala/Thr and Thr/Thr) versus the wild‐type homozygotes (Ala/Ala), the pooled OR was 1.18 (95% CI = 1.04–1.34, P = 0.062 for heterogeneity), for Thr/Thr versus Ala/Ala the pooled OR was 1.17 (95% CI = 1.05–1.41 P = 0.087 for heterogeneity). In the stratified analysis by ethnicity, the significantly risks were found among Asians but not Caucasians. This meta‐analysis suggests that the FABP2 (rs1799883) Ala54Thr polymorphisms are associated with increased susceptibility to T2DM risk among Asians but not Caucasians.  相似文献   
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