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1.
雷山髭蟾卵团自然状态下发育观察初报 总被引:2,自引:0,他引:2
2007年11月至2008年4月在贵州雷公山自然保护区对雷山髭蟾卵团的自然发育进行了观察.研究区域位于海拔1500~1600 m的中山地带.雷山髭蟾11月中旬在森林溪流水中交配产卵,共发现6个产卵场和23个卵团.参照赵尔宓的蛙类胚胎及蝌蚪发育分期,将雷山髭蟾卵团发育分为3个阶段.早期发育阶段,从产下卵到原肠胚晚期,此阶段肉眼不能辨别卵粒变化情况;中期发育阶段,即神经板期到鳃血循环期,肉眼能识别出卵粒变化;晚期发育阶段,即角膜透明期到蝌蚪下水自由游泳.观察结果表明:未受到冰雪冻凝卵团早期发育平均为60 d,中期74 d,晚期12 d,总计146 d.受到雪灾冻凝的卵团早期发育平均为109 d,中期22 d,晚期13 d,总计144 d.经t检验,非冻凝的卵团和冻凝的卵团在早期和中期发育时间存在极显著差异,而晚期和总的发育时间无差异,说明雷山髭蟾胚胎早期发育若因外界不利因素延迟,会在后期自动调节发育速度,加快发育. 相似文献
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《四川动物》2017,(5)
2014年10月—2016年6月,采用野外定点观察的方法系统观察雷山髭蟾Vibrissaphora leishanensis的繁殖生态习性。研究表明:雷山髭蟾求偶、交配、产卵均在水体中进行;繁殖期在每年的9月底至12月底,11月中旬最集中;雄性的体长和体质量均显著大于雌性;繁殖行为包括筑"巢"、鸣叫求偶、抱对、产卵,雄蟾单个鸣叫,抱对时雄蟾主动。有共用一个"巢"穴抱对产卵的习性和集群产卵的行为。卵群直径65.13~100.47 mm,平均77.73 mm±9.47 mm(n=54);窝卵数162~394粒,平均226.79粒±7.89粒(n=54);卵径2.06~5.18 mm,平均3.82 mm±0.91 mm(n=270);孵化期为107~157 d,平均127.71 d±7.38 d(n=54)。 相似文献
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峨眉髭蟾精子形态结构及分类学意义 总被引:1,自引:0,他引:1
应用透射电镜、扫描电镜和光学显微镜对峨眉髭蟾(Vibrissaphoraboringii)精子的形态和超微结构研究的结果表明:峨眉髭蟾的精子具角蟾科物种精子基本的形态和结构特征,即精子头部呈螺旋状,尾部呈弯曲状;精子具锥形的顶体、纤维束构成的穿孔器、平行排列的中心粒和双轴丝;线粒体位于尾部;精子核窝不明显、无轴纤维和波动膜等特征。此外,对已有报道的角蟾科和无尾类物种精子的特征进行分析比较表明:(1)角蟾科精子细胞核呈螺旋状,中心粒平行排列,尾部具双轴丝等结构不同于无尾类其他科精子的结构,具有明显的科间差别;(2)角蟾科精子各部的量度,尾部线粒体的分布和数量,以及轴丝的排列等特征在属间和种间表现出明显的差异;(3)峨眉髭蟾和东南亚拟髭蟾指名亚种精子的形态和超微结构存在明显的差异。 相似文献
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应用透射电镜、扫描电镜和光学显微镜对峨眉髭蟾(Vibrissaphora boringii)精子的形态和超微结构研究的结果表明:峨眉髭蟾的精子具角蟾科物种精子基本的形态和结构特征,即精子头部呈螺旋状,尾部呈弯曲状;精子具锥形的顶体、纤维束构成的穿孔器、平行排列的中心粒和双轴丝;线粒体位于尾部;精子核窝不明显、无轴纤维和波动膜等特征。此外,对已有报道的角蟾科和无尾类物种精子的特征进行分析比较表明:(1)角蟾科精子细胞核呈螺旋状,中心粒平行排列,尾部具双轴丝等结构不同于无尾类其他科精子的结构,具有明显的科间差别;(2)角蟾科精子各部的量度,尾部线粒体的分布和数量,以及轴丝的排列等特征在属间和种间表现出明显的差异;(3)峨眉髭蟾和东南亚拟髭蟾指名亚种精子的形态和超微结构存在明显的差异。 相似文献
11.
Miguel Tejedo 《Oecologia》1992,90(2):294-296
Summary A trade-off between size and number of offspring was not found for females of similar sizes of the natterjack toad (Bufo calamita). Moreover, for large females, clutches with higher number of eggs had larger eggs as well. This suggests that larger females produce more numerous and larger eggs because they potentially have more energy available for reproduction. Egg size diminished allometrically with clutch size. Egg size, however, did not increase offspring fitness. Therefore, this allometric decrease may be considered a consequence of phylogenetic constraints rather than a result of optimizing selection. 相似文献
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Allen TD Rutherford SA Murray S Sanderson HS Gardiner F Kiseleva E Goldberg MW Drummond SP 《Nature protocols》2007,2(5):1173-1179
This protocol details methods for the generation of cell-free extracts and DNA templates from the eggs and sperm chromatin, respectively, of the clawed toad Xenopus laevis. We have used this system with scanning electron microscopy (SEM), as detailed herein, to analyze the biochemical requirements and structural pathways for the biogenesis of eukaryotic nuclear envelopes (NEs) and nuclear pore complexes (NPCs). This protocol requires access to female frogs, which are induced to lay eggs, and a male frog, which is killed for preparation of the sperm chromatin. Egg extracts should be prepared in 1 d and can be stored for many months at -80 degrees C. Demembranated sperm chromatin should take only approximately 2-3 h to prepare and can be stored at -80 degrees C almost indefinitely. The time required for assembly of structurally and functionally competent nuclei in vitro depends largely on the quality of the cell-free extracts and, therefore, must be determined for each extract preparation. 相似文献
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R. C. Beattie 《Journal of Zoology》1980,190(1):1-25
The mucopolysaccharide capsules surrounding eggs of the Common frog, Rana temporaria temporaria L. were investigated. Frogs were obtained from ponds in northern England ranging in altitude from 46 to 838 m. Egg capsules acted as insulators, keeping the centre of an egg mass warmer on average than the surrounding water. The size of an egg capsule and its insulating efficiency varied in different pond waters. Egg capsules in water from highland ponds were larger and more efficient insulators than egg capsules in water from lowland ponds. In a series of laboratory experiments the factors controlling capsular swelling were investigated). The ionic concentration of the fluid surrounding the eggs was found to be the principal factor involved, but the temperature and pH of the fluid and the valency and identity of the ions in solution were also important. The water chemistry of ponds varied with altitude. This accounted for the differential swelling of egg jelly in highland and lowland ponds. The fact that egg capsules are larger in highland pond water may increase egg survival at low temperatures. This is probably fortuitous as there is no evidence to suggest that frogs select their breeding ponds because the water in them will promote capsular swelling. 相似文献
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The major isotype of parvalbumin has been isolated from the skeletal muscle of the toad, Bufo bufo japonicus. Unlike the skeletal muscle of every frog so far examined (Rana esculenta, Rana temporaria, and Rana catesbeiana), which contains two major isotypes of parvalbumins, toad skeletal muscle has been shown to contain only one isotype, but the content of parvalbumin in toad skeletal muscle was similar to the sum of those of the two isotypes in skeletal muscles of frogs. This feature of toad skeletal muscle is advantageous to clarify the physiological role of parvalbumin. The relative molecular mass of toad parvalbumin was estimated to be 12,200 by SDS-polyacrylamide gel electrophoresis. The isoelectric point was determined to be 4.81 by polyacrylamide gel isoelectric focusing. The amino acid composition indicated that toad parvalbumin corresponds to bullfrog (R. catesbeiana) pI 4.97 parvalbumin, showing that toad parvalbumin is genetically an alpha-parvalbumin. It was also revealed by the amino acid composition that toad parvalbumin is distinctly different from any of the parvalbumins from frogs. The ultraviolet spectrum of toad parvalbumin is consistent with its amino acid composition. The ultraviolet difference spectrum of the Ca2+-loaded form vs. the metal-free form indicates that some Phe residues in the toad parvalbumin molecule are affected by a conformational change associated with Ca2+ binding. On electrophoresis in polyacrylamide gel in 14 mM Tris and 90 mM glycine, the metal-free and Mg2+-loaded forms of toad parvalbumin migrated twice as fast as the Ca2+-loaded form.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
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Noritaka Ichikawa 《Journal of Ethology》1991,9(1):25-29
Egg mass destroying behaviour of femaleLethocerus deyrollei and male defending behaviour were observed in a densely vegetated concrete pond. In 3 of 9 cases of male-female interactions,
the males successfully guarded their egg masses. In 4 of the 6 remaining cases in which the egg masses were destroyed by the
female, females successfully took over the mate and laid their own egg masses the same night. These results suggest that male
brooding guards the egg mass from females, as well as supplying eggs with water. 相似文献
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Loeske E. B. Kruuk Jason S. Gilchrist Nick H. Barton 《Evolution; international journal of organic evolution》1999,53(5):1611-1616
Reproductive isolation between two taxa may be due to endogenous selection, which is generated by incompatibilities between the respective genomes, to exogenous selection, which is generated by differential adaptations to alternative environments, or to both. The continuing debate over the relative importance of either mode of selection has highlighted the need for unambiguous data on the fitness of hybrid genotypes. The hybrid zone between the fire-bellied toad (Bombina bombina) and the yellow-bellied toad (B. variegata) in central Europe involves adaptation to different environments, but evidence of hybrid dysfunction is equivocal. In this study, we followed the development under laboratory conditions of naturally laid eggs collected from a transect across the Bombina hybrid zone in Croatia. Fitness was significantly reduced in hybrid populations: Egg batches from the center of the hybrid zone showed significantly higher embryonic and larval mortality and higher frequencies of morphological abnormalities relative to either parental type. Overall mortality from day of egg collection to three weeks after hatching reached 20% in central hybrid populations, compared to 2% in pure populations. There was no significant difference in fitness between two parental types. Within hybrid populations, there was considerable variation in fitness, with some genotypes showing no evidence of reduced viability. We discuss the implications of these findings for our understanding of barriers to gene flow between species. 相似文献
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Embryonic development of the Pacific lamprey, Entosphenus tridentatus, from Japan is described. Egg sizes averaged 1.249 mm (longest axis) and 1.145 mm (shortest axis), the time required for hatching being 11 days at 18 degrees C, shorter than previously reported for a lower water temperature (19 days at 15 degrees C). Early development in E. tridentatus proceeded at a similar rate to that in other lampreys, in spite of different rearing water temperatures for the latter, indicating possible specific differences in basic developmental rates. 相似文献
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Bucciarelli T Sacchetta P Amicarelli F Petruzzelli R Melino S Rotilio D Celli N Di Ilio C 《The international journal of biochemistry & cell biology》2002,34(10):1286-1290
To investigate structural relationship between amphibian and mammalian GSTs the complete amino acid sequence of the major form of glutathione transferase present in toad liver (Bufo bufo) was determined. The enzyme subunit is composed of 210 amino acid residues corresponding to a molecular mass of 24,178 Da. In comparison with the primary structure of amphibian bbGSTP1-1, toad liver GST showed 54% sequence identity. On the other hand, toad liver GST showed about 45-55% sequence identity when compared with other pi class GST and less then 25% identity with GST of other classes. Amino acid residues involved in the H site and in the key and lock structure of the toad enzyme are significantly different from those of bbGSTP1-1 and other mammalian pi class GST. On the basis of its structural and immunological properties the toad liver GST, indicated as bbGSTP2-2, could represent the prototype of a subset of the pi family. 相似文献
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The rates of water loss of domestic chicken eggs were varied during incubation to measure the osmoregulatory ability of the avian embryo. Egg water loss was increased by drilling holes in the eggshell over the airspace on day 13 (I = 21 days) and then placing these eggs in a low relative humidity (r.h.: 0-10%) incubator until hatch. Egg water loss was decreased by placing other eggs in a high-r.h. (85-90%) incubator on day 0. Eggs with low water loss (approximately 6% of initial fresh mass [IFM]) produced embryos and yolks that were not different in wet or dry mass when compared to control eggs that lost approximately 12% of IFM. However, 1-4 gm of excess albumen were left in low-water-loss eggs on day 21. Hatching success was 71% and 89% for low and control eggs, respectively. Low egg water loss did not appear to disturb embryonic growth. The allantoic fluid volume and millimolar allantoic Na+ and Cl- ions declined faster with high and slower with low rates of water loss. Thus, excess water was lost as a result of increased movement of water out of allantoic fluid, which was due to increased active transport of Na+ ions by the chorioallantoic membrane (CAM). Eggs with high water loss had elevated Cl- levels after day 17 in plasma and amniotic fluid, which indicated a period of osmotic stress after depletion of allantoic fluid between day 18 and hatch. The decrease in wet embryo mass measured in embryos from high-water-loss eggs was due principally to dehydration of skin. Embryonic skin may serve as an emergency water reservoir during osmotic stress. Dehydrated chicks produced from high-water-loss eggs were 6 gm less in wet mass at hatch compared to controls. However, these chicks regained the water deficit 7 days after hatch and grew at a rate not different from control chicks through 6 weeks of age. Total egg water loss of 12% of IFM results in highest hatching success. However, water losses between 6% and 20% of IFM do not appear to affect adversely the growth or water content of the chick. Water losses above 20% of IFM cause early depletion of allantoic fluid, prolong the period of osmotic stress, and result in subsequent dehydration of blood, amniotic fluid, and embryonic skin.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献