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A highly upregulated gene during tail regeneration in lizards is Wnt2b, a gene broadly expressed during development. The present study examines the distribution of Wnt proteins, most likely wnt2b, by western blotting and immunofluorescence in the blastema-cone of lizards using a specific antibody produced against a lizard Wnt2b protein. Immunopositive bands at 48–50 and 18 kDa are present in the regenerative blastema, the latter likely as a degradation product. Immunofluorescence is mainly observed in the wound epidermis, including in the Apical Epidermal Peg where the protein appears localized in intermediate and differentiating keratinocytes. Labeling is more intense along the perimeter of keratinocytes, possibly as a secretory product, and indicates that the high epidermal proliferation of the regenerating epidermis is sustained by Wnt proteins. The regenerating spinal cord forms an ependymal tube within the blastema and shows immunolabeling especially in the cytoplasm of ependymal cells contacting the central canal where some secretion might occur. Also, regenerating nerves and proximal spinal ganglia innervating the regenerating blastema contain this signaling protein. In contrast, the blastema mesenchyme, muscles and cartilage show weak immunolabeling that tends to disappear in tissues located in more proximal regions, close to the original tail. However, a distal to proximal gradient of Wnt proteins was not detected. The present study supports the hypothesis that Wnt proteins, in particular Wnt2b, are secreted by the apical epidermis covering the blastema and released into the mesenchyme where they stimulate cell multiplication.  相似文献   
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水热环境对白条草蜥孵化卵和孵出幼体表型特征的影响   总被引:2,自引:0,他引:2  
吴义莲  许雪峰 《动物学报》2007,53(6):966-973
用4×2(温度×湿度)八种水热环境孵化安徽滁州琅琊山白条草蜥(Takydromus wolteri)卵,观测孵化卵重量变化、胚胎利用卵内物质和能量以及孵出幼体的特征。卵从孵化环境中吸水导致重量增加,卵重量的增加与入孵卵重量、孵化温度和基质湿度有关。两种孵化基质湿度对孵化期、孵化成功率、孵出幼体性比和大小都无显著影响。孵化期随恒定孵化温度的升高而缩短,27℃、30℃和33℃孵化期分别为32.5、24.9和23.0d,波动温度孵化期为31.1d。33℃孵化成功率最低(42.8%)。温度对孵化成功率和孵出幼体的性别无显著影响,但显著影响胚胎对卵内物质的动用、幼体的大小和重量。33℃不适宜孵化白条草蜥卵,该温度下孵出的幼体躯干小,剩余卵黄多,运动能力差。27℃和波动温度中孵出幼体躯干发育良好,各项被测定的特征指标极其相似。  相似文献   
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Identifying evolutionary and developmental mechanisms underlying consistent between‐individual differences in behaviour is the main goal in ‘animal personality studies’. Here, we explored whether activity and risk‐taking varied consistently between individuals and correlated to various – potentially fitness linked – male traits in Carpetan rock lizards (Iberolacerta cyreni). Lizards showed significant consistency within both behaviours, implying the presence of activity and risk‐taking personalities. However, there were no correlation between activity and risk‐taking, neither on the between‐ nor on the within‐individual levels, implying the absence of a behavioural syndrome. We found a strong link between the intensity of blood parasite (Haemogregarinidae) infection and risk‐taking: lizards with higher infection intensity took more risk. While we cannot distinguish cause from causative in the parasite intensity – risk‐taking correlation – our results are in line with the asset protection hypothesis predicting that individuals with lower future reproductive value should focus on the current reproductive event and take higher risk.  相似文献   
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The lacertid lizard ( Gallotia stehlini ), an endemic of Gran Canaria, shows no visually obvious geographic variation, yet all seven scalation characters that were examined exhibit significant geographic variation. The number of collar scales, scales along the ventral trunk and femoral pores are correlated with habitat type, while the number of femoral pores is correlated negatively with altitude. Mantel tests were used to compare simultaneously an observed pattern with three hypothesized patterns (habitat type, altitude and proximity). They indicate that, while several individual characters are significantly associated with the putative causal factors of habitat type and altitude, there is no association between an overall scalation distance matrix and habitat type, or altitude when the effect of proximity is removed. Consequently, one should consider the individual characters as well as the multivariate generalized distances. Some of the observed patterns of geographic variation in scalation are very similar to those of the small scincid lizard Chalcides sexlineatus on Gran Canaria and also parallel the altitudinal and latitudinal variation in the scalation of the Tenerife lacertid ( Galotia galloti ). The low level of congruence in patterns of geographic variation in individual characters (i.e. some vary with latitude, some with altitude and one varies with longitude) is consistent with the hypothesis that ecogenetically caused geographic variation may result in lower inter-character congruence than phylogenetically caused geographic variation.  相似文献   
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Brown RP 《Genetica》1997,101(1):67-74
Heterogeneous phenotypic correlations may be suggestive of underlying changes in genetic covariance among life-history, morphology, and behavioural traits, and their detection is therefore relevant to many biological studies. Two new statistical tests are proposed and their performances compared with existing methods. Of all tests considered, the existing approximate test of homogeneity of product-moment correlations provides the greatest power to detect heterogeneous correlations, when based on Hotelling's z*-transformation. The use of this transformation and test is recommended under conditions of bivariate normality. A new distribution-free randomisation test of homogeneity of Spearman's rank correlations is described and recommended for use when the bivariate samples are taken from populations with non-normal or unknown distributions. An alternative randomisation test of homogeneity of product-moment correlations is shown to be a useful compromise between the approximate tests and the randomisation tests on Spearman's rank correlations: it is not as sensitive to departures from normality as the approximate tests, but has greater power than the rank correlation test. An example is provided that shows how choice of test will have a considerable influence on the conclusions of a particular study. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   
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The morphological origin of the dark and pink‐orange areas in the skin of the venomous lizard Heloderma suspectum is not known. Histology and electron microscopy show that dark‐grey areas of the skin derived from dermal chromatophores localized in specific areas present underneath the epidermis. A dynamic chromatophoric unit in the dermis is absent. In the darkest areas of the skin, the accumulation of melanosomes in cells of the beta‐layer contributes to increase the black intensity. In the orange‐pink areas, the superficial dermis contains xantophores storing numerous carotenoid vesicles, rare or absent lamellated pterinosomes and a variable number of melanosomes. These xanto‐melanophores predominate over the remaining chromatophores and form a continuous stratum underneath the epidermis. Beneath this lipoid‐rich stratum, iridophores are infrequent and do not form a continuous layer in the dermis. In the paler areas of the skin, melanophores are sparse in both superficial and deeper part of the dermis where irregularly oriented bundles of collagen fibrils are present. The prevalent xanto‐melanophores localized in the pink‐orange areas of the skin contribute to an effective sunlight protection in desert conditions in addition to the darker regions occupied by melanophores.  相似文献   
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