甲基胆蒽对蝾螈中胚层分化的影响

前言对哺乳类有引瘤作用的物质,在两栖类的成体中,不论是有尾类(Breedis,1951,1952;和,1954)或者无尾类(曾弥白,1956a),都可以引起恶性瘤肿,虽然瘤肿形成的频率远没有在哺乳类高。对于两栖类幼体,或者正在发育中的胚胎组织,引瘤物质却表现了不同的作用。它们可以引起形态建成的变化。Waddington 和 Needham(1935)将多种多环碳氢化物塞入早期原肠胚的囊胚腔,发现其中几种诱导了神经组织的发生。为了避免塞入法可能引起的机械的影响,沈诗章(Shen,1942)用二苯骈蒽内琥珀酸钠(Na-dibenz-anthracene-endo-succinate)的水溶液处理早期原肠胚的预定表皮,也得到了同样     

用轻度的细胞解体研究两栖类外胚层的反应能力

目次Ⅰ.绪论Ⅱ.材料和方法Ⅲ.实验一.外胚层反应能力的改变1.背唇形成以前,外胚层的反应能力2.背唇形成以后,外胚层的反应能力3.小结二.神经组织的分化和外胚层的年龄以及处理的时间的关系1.早期原肠胚的外胚层2.中期原肠胚的外胚层3.晚期原肠胚的外胚层4.胚孔关闭以后的外胚层     

AN EXPERIMENTAL ANALYSIS OF THE ROLE OF CYTOPLASMIC FOUNTAIN STREAMING IN FURROW ESTABLISHMENT

During furrow establishment the equatorial cell surface is altered so that it becomes capable of exerting the physical force required for cytokinesis. It has been suggested that the alteration results from deposition of a furrow-organizing substance at the equator by convergence of “fountain streaming” patterns of cytoplasmic flow. The purpose of this investigation was to determine whether a fountain streaming pattern is essential for furrow establishment. The shape of sand dollar eggs was altered before the time of furrow establishment in ways that would greatly disrupt fountain streaming. Shapes that should have abolished regions of convergence and shapes that should have created several such regions were created by notching and perforating cells. Furrow establishment took place under circumstances that would be highly unlikely if a fountain streaming pattern of cytoplasmic currents were necessary.     

THE ROLE OF POPULATIONAL DIFFERENTIATION IN EXPERIMENTAL INFECTION OF PROSOPIS BY PHORADENDRON

Experimental infection of Prosopis species with the mistletoe Phoradendron tomeniosum subsp. tomentosum in a uniform garden demonstrated that differences in infection success between species, populations, and individuals can be caused by genetically-based differences in both hosts and parasites. Prosopis glandulosa var. glandulosa was least resistant to infection; P. laevigata was more resistant; and P. torreyana was most resistant. A population of P. glandulosa var. glandulosa grown from seeds collected in the lower Rio Grande valley was significantly more resistant to infection than three populations of the same variety from central and northern Texas. The higher resistance of the Rio Grande valley population appears to be due to introgression with P. laevigata. The experimental population of Phoradendron tomentosum subsp. tomentosum from northeastern Mexico and the population of the same subspecies from southern Texas had greater infectivity than did those from central and northern Texas, corresponding to the greater resistance of the southern Prosopis populations.     

THE EVOLUTION OF MATERNAL INVESTMENT IN LIZARDS: AN EXPERIMENTAL AND COMPARATIVE ANALYSIS OF EGG SIZE AND ITS EFFECTS ON OFFSPRING PERFORMANCE

I used comparative and experimental analysis of egg size in a Sceloporus lizard to examine a fundamental tenet of life-history theory: the presumed trade-offs among offspring number, offspring size, and performance traits related to offspring size that are likely to influence fitness. I analyzed latitudinal and elevational patterns of egg life-history characteristics among populations and experimentally manipulated egg size and hatchling size by removing yolk from the eggs to examine the causal bases of population differences in offspring traits. Mean clutch size among populations increased to the north (seven vs. 12 eggs/clutch, California vs. Washington), whereas egg size decreased (0.65 g vs. 0.40 g). The elevational patterns in southern California paralleled the latitudinal trends. Several offspring life-history traits that are correlated with egg size also varied geographically; these traits included incubation time, hatchling size, growth rate, and hatchling sprint performance. Hatchling viability of experimentally reduced eggs was remarkably high (~70%), even when up to 50% of the yolk was removed. The experimentally reduced eggs and hatchlings demonstrated the degree to which size influences each of the offspring life-history traits considered. Northern eggs hatched sooner, in part because of their small size. Though growth rate is allometrically related to size within each population (i.e., smaller hatchlings grow faster on a mass-specific basis), population differences in growth rate, as measured in the laboratory, are likely to reflect genetic differentiation in the underlying physiology of growth. Moreover, smaller juveniles, because of experimental reduction, had slower sprint speeds than larger juveniles. The slower sprint speed of hatchlings from Washington compared to hatchlings from California is thus largely due to the fact that eggs are smaller in the Washington population. These results provide a basis for interpreting the evolutionary divergence of the suite of traits involved in the evolution of maternal investment per offspring in lizards. For example, evolutionary divergence in some offspring traits functionally related to size (e.g., sprint speed) may be constrained, relative to traits that are determined by other aspects of development or physiology (e.g., growth). I also discuss issues relating to the evolution of maternal investment that could be tested in laboratory and natural populations using experimentally reduced offspring.     

吉兰泰杜氏盐藻中类胡萝卜素的分析和鉴定

利用高压液相色谱（ＨＰＬＣ）技术及ＩＲ、＾１Ｈ ＮＭＲ、ＭＳ、ＵＶ等现代测试手段,对吉兰泰杜氏盐藻中的类胡萝卜素等色素及胡萝卜素异构体进行了分析与鉴定。研究结果表明,吉兰泰杜氏盐藻中含有１１种类胡萝卜素,其中β－胡萝卜素包含７－顺式、９－顺式、１５－顺式、全反式等４种异构体。吉兰泰杜氏盐藻中的这些类胡萝卜素对人体十分有益,具有开发利用的价值。     

湖北省23种植物油脂分析

本文报道了湖北省15个科中23种植物油脂的含油量、碘值、皂化值,以及用气相色谱法,对它们常见脂肪酸组成的定量分析结果。我们自承担“全国植物油脂研究”课题以来,对湖北省野生油脂植物资源进行了广泛的调查,收集了有关植物的果实和种子,进行了109种植物油脂的含油量、碘值、皂化值和常见脂肪酸的测定。后又到神农架等地对15个科23种植物油脂作了进一步的调查研究和分析。其中13种植物油脂数据在国内外尚未见报道。