泽蛙雌核单倍体几种用工酶基因表达的研究

本研究用聚丙烯酰胺凝胶垂直平板电泳,比较泽蛙雌核生殖单倍体和泽蛙二倍体在鳃盖闭合期的乳酸脱氢酶同工酶（LDH）、苹果酸脱氢酶同工酶（MDH）、葡萄糖-6-磷酸脱氢酶同工酶（G-6-PDH）和酯酶同工酶（EST）的表型。实验表明,单倍体的上述同工酶区带数和活力与同胚期的二倍体比较,差异甚大。由此,作者认为,泽蛙单倍体同工酶基因的表达异常是由于缺少另一套染色体基因的相互作用。     

泽蛙雌核生殖单倍体产生过程的细胞学研究

丁汉波等(1965)在福建无尾两栖类的杂交实验中发现,泽蛙(Rana limnochris Boie)♀×黑眶蟾蜍(Bufo melanostictus Schneider)♂可以产生泽蛙雌核单倍体,但是这种组合的“杂交”如何产生单倍体,在细胞学方面未深入研究。为了进一步了解其发育机理,本文主要从细胞学的角度探讨黑眶蟾蜍精子诱发泽蛙卵进行雌核生殖的过程。     

泽蛙雌核单倍体几种同工酶基因表达的研究

本研究用聚丙烯酰胺凝胶垂直平板电泳,比较泽蛙雌核生殖单倍体和泽蛙二倍体在鳃盖闭合期的乳酸脱氢酶同工酶(LDH)、苹果酸脱氢酶同工酶(MDH)、葡萄糖-6-磷酸脱氢酶同工酶(G-6-PDH)和酯酶同工酶(EST)的表型。实验表明,单倍体的上述同工酶区带数和活力与同胚期的二倍体比较,差异甚大。由此,作者认为,泽蛙单倍体问工酶基因的表达异常是由于缺少另一套染色体基因的相互作用。     

泽蛙单倍体细胞RNA含量对胚胎发育和成活的影响

对两栖类单倍体的综合症以及死亡原因,前人有许多不同认识,本文用实验说明,单倍体细胞的RNA含量不及二倍体的一半,并认为,单倍体泽蛙的死亡原因与其细胞中RNA含量不足密切相关。     

泽蛙雌核生殖单倍体发育中的核质关系

本文详细比较了由同一母体卵子产生的泽蛙单倍体和二倍体的个体发育,并依据实验结果,讨论了个体发育中的核质关系。作者认为,个体发育始末,细胞质虽然影响早期的发育和细胞分化,但是,细胞核一直起到主导作用。没有正常的染色体组数,就没有正常的细胞分化和个体发育。     

上海农田泽蛙蛰眠状况初步调查

于2004～2005年冬季对上海农田泽蛙的蛰眠状况进行了初步调查。结果表明,农田中的路径、田埂和沟渠岸边地下洞穴是泽蛙的主要越冬场所。蛰眠洞穴共用率高达34.0%,超过62.2%的泽蛙与其它个体共用洞穴蛰眠,各共用洞穴内的泽蛙只数为2～6只不等。泽蛙主要利用已有的地下洞穴蛰眠。86.6%蛰眠期的泽蛙为1龄个体。     

上海郊区农田泽蛙种群动态和肥满度状况初探

2005年4～10月,采用样线法,对上海郊区农田泽蛙（Rana limnocharis）非蛰眠期的种群数量和肥满度进行了研究。逐月共捕获泽蛙371只,对不同月份和不同年龄组泽蛙的体长、体重和肥满度进行数据分析。结果表明上海郊区泽蛙的肥满度随不同月份和不同年龄呈现显著性差异。种群在繁殖前的5月份肥满度最高,8月份肥满度最小。肥满度Kwl值随泽蛙年龄的增加而增大,K值随泽蛙年龄的增大而减小。2龄泽蛙的肥满度增幅最大。上海郊区泽蛙的年度种群数量波动呈双峰型,峰值在7月和9月。Kwl值比K值更加敏感。     

中国林蛙的骨骼系统

研究了中国林蛙Rana chensinensis的骨骼系统,对各部分的形态结构进行了详细的描述.鼻骨与已报道的粗皮蛙和泽蛙有所不同;鼻腔骨的形状与粗皮蛙差异极大,而与泽蛙较为接近;第8椎体双凹型,属典型的参差型脊柱;肩胸骨的基部无分叉,也无缺刻,与泽蛙和粗皮蛙不相同,上胸骨较粗皮蛙大,形状与泽蛙有差异.肩带为固胸型.     

温州不同区域泽蛙染色体组型比较研究

本文报道温州四个不同区域泽蛙（ Ｒａｎａｌｉｍｎｏｃｈａｒｉｓ Ｂｏｉｅ） 的染色体组型。结果表明四处泽蛙均为２ｎ＝２６ （５ ＋８） , ＮＦ＝５２ 。温州市区、乐清、洞头泽蛙在６ｐ 上有一对次缢痕, 文成泽蛙在７ｐ 上有一对次缢痕。洞头、文成泽蛙ｎｏｓ－４、９、１１ 为ＳＭ 染色体, 其余均为Ｍ 染色体; 温州泽蛙ｎｏｓ－３、４、８ 为ＳＭ, 其余均为Ｍ 染色体;乐清泽蛙ｎｏｓ－４、９ 为ＳＭ 染色体, 其余均为Ｍ 染色体。通过温州不同区域以及国内外其它地区泽蛙染色体组型的比较, 结果差异明显, 显示泽蛙核型的多样性。     

云南南部3产地泽蛙核型比较研究

对采自云南个旧、绿春、江城3地的泽蛙进行染色体核型分析。结果表明,3地的泽蛙核型均为2n=26（5L＋0M＋8S）,NF=52,染色体次缢痕均出现在6p上。个旧大屯泽蛙的No．3为SM染色体,其余染色体均为M染色体;绿春大黑山的泽蛙No．2、6、7为SM染色体,其余均为M染色体;江城康平的泽蛙No．2、9均为SM染色体,其余为M染色体,显示出不同地区泽蛙核型的差异性。比较了滇南3地和国内外不同地区泽蛙染色体核型变化,结果显示,染色体核型模式及其大型染色体组比较稳定,但次缢痕位置不稳定,小型染色体组变异较大。根据泽蛙次缢痕的地理演化趋势,推测次缢痕位于7p上是一种原始类型,位于6p上是一种较为进化的类型,位于9p上是一种特化的类型。泽蛙的分布及核型分化与第三纪欧亚大陆边缘断裂形成日本海有关,也与第四纪冰期气候变化和随之产生的泽蛙南迁北移有关。     

滇产植物的皂素成份研究IV，IV中药三七的两种皂甙（1）

我们从三七(Panax notoginseng (Burk.) F. H. Chen) 根中分离得皂甙A和皂甙C.根据熔点、比旋光度及元素分析、红外、核磁证明皂甙A与 S. Shibata等从同属植物人参(Panax ginseng)中分离得到Ginsenoside-Rg1 (6, 20-di-O-β-D-glucosyl-20S-Protopanxatriol)是同一化合物;皂甙C与 Ginsenoside- Rb2(20S- Proto-panaxadiol-3-[0-β-D-glucopyranosy1 (l→2 )-β-D-glucopyranoside]-20-[O-α-L-arabino-pyranosyl(1→6)-β-D-glucopyranoside] )是同一化合物。     

Analysis of haploid development based on expression patterns of developmental genes in the medaka Oryzias latipes

The abnormalities of haploid medaka embryos were characterized by comparative analysis of histologic sections and expression patterns of some developmental marker genes between haploids and diploids to clarify whether medaka haploids are useful for identifying mutants. During gastrulation, an obvious defect was first observed as a delay of epiboly and involution. This delay was shown to be caused not by the perturbation of mesoderm induction, but by widespread cell death and disorganization of cell arrangement in the blastoderm. This disorganization of cell arrangement was also detected in various organs, such as the brain, somite and notochord, at a late developmental stage. Ten days after fertilization, a small head and a short body axis were formed; these changes were also observed in haploid embryos in other species, but their cause is unknown. Based on the expression patterns of HNF3beta and goosecoid, it was demonstrated that a short and impotent prechordal plate induced near the marginal zone in haploid embryos was responsible for this defect. However, in these experiments it was also demonstrated that many major organs in haploids, such as the somite and notochord, differentiated incompletely but were present. Therefore, it was concluded that haploid screening is suitable for identifying mutations revealed by an obvious phenotype, such as dorsoventral polarity.     

Ribosomal RNA synthesis in haploid and diploid loach embryos]

rRNA synthesis was compared in the loach haploid (In) and diploid (2n) embryos. The relative intensity of synthesis was evaluated by 14C-uridine incorporation in 27S and 18S rRNA isolated from ribosomes taking into account label incorporation into total acid-soluble fraction and phosphrylated uridine derivatives. Label incorporation into rRNA, in reference with DNA content in 1n and 2n embryos, suggests that the level of rRNA synthesis per DNA unit in haploids is twice that in diploids whereas, in reference per cell, the same amount of ribosomes is synthesized both in haploids and diploids. The data obtained show that the amount of rRNAs synthesized in the loach embryogenesis does not depend on ploidy.     

Kinetics of the synthesis of nucleic acids in haploid and diploid loach embryos]

Al kinetic analysis of incorporation of the mixture of 3H-nucleosides in the nucleic acid fractions was carried out to examine the mechanisms of compensation of the genetic material deficiency. Both the haploid and diploid embryos of the loach (Misgurnus fossilis L.) were analyzed. When comparing the DNA and RNA syntheses, the level of phosphorylation (nucleotide pool) in the both genetic variants was under control. The rate of incorporation of the labelled nucleosides in DNA was shown to be higher in haploids at the early developmental stages than in diploids but later it became the same. The increased level of DNA replication in the early haploid embryos was due to the compensatory increase of the cell number in them as compared with the diploid ones. The rate of total RNA synthesis corrected by the differences in the rate of nucleoside phosphorylation varied directly with the degree of ploidy at the blastula stage; at the gastrula stage the value of RNA synthesis per haploid genome was compensated, and at the stage of organogenesis the production of total RNA, as calculated per cell, became in haploids even higher than in diploids. The data obtained suggest the essential changes in the patterns of RNA synthesis control during development.     

Chromosome studies of progenies of tetraploid female rainbow trout

Summary Nine induced tetraploid females were artificially inseminated by UV-irradiated sperm collected from diploid males, in order to induce the gynogenetic development of their ova. Most of the resulting embryos were diploid (or minor aneuploids). Several gynogenetic tetraploids, likely to issue from unreduced ova, were also detected in these progenies. The same females fertilized by normal sperm of diploid males gave a majority of triploids and several pentaploids, while the fertilization by normal sperm of tetraploid males gave rise to a majority of tetraploids and one hexaploid. The same crosses, after the eggs had been heat-shocked to double the maternal genetic contribution, yielded about three-quarters pentaploids and one quarter haploids (normal sperm of diploids), or three-quarters hexaploids and one quarter diploids (normal sperm of tetraploids). These haploids and diploids are likely to result from androgenesis.     

Development of porcine blastocysts from in vitro- matured and activated haploid and diploid oocytes

The purpose of this study was to determine the developmental capacity of electro-activated porcine oocytes. Follicular oocytes collected from gilts at local slaughterhouses were matured for 48 h and were then subjected to a single square pulse of direct current for 100 rhojusec at 1,500 V/cm for activation. To obtain activated diploid oocytes, some were treated with 5.0 micro/ml cytochalasin B for 4 h immediately after electro-activation. The frequency of activation ranged from 96 to 100%. While 91% of activated oocytes that had not been treated with cytochalasin B had 2 polar bodies and a nucleus (haploids), 92% of the oocytes treated with cytochalasin B had only the first polar body and 2 nuclei (diploids). Haploids and diploids were further cultured in TCM-199 medium that contained 10% (v/v) heat- treated fetal calf serum (FCS) and 0.1 mg/ml sodium pyruvate (mTCM) or in Whittenk medium plus 0.4% (w/v) bovine serum albumin (BSA). The frequency of abnormal oocytes was significantly higher in mTCM (83%) than in Whitten's medium (65%) 96 h after the electro-activation (P < 0.01), suggesting that Whitten's medium supported the development of activated oocytes beyond the morula stage. In all cases, several oocytes developed to the blastocyst stage 144 h after electro- activation (1 to 12%). The frequency was significantly higher in the case of diploids cultured in Whitten's medium (12%) (P < 0.01) than in the case of haploids cultured in Whitten's medium (4%), or in the case of haploids cultured in mTCM (1%). The mean number of nuclei per blastocyst was significantly lower in mTCM (haploids, 15; diploids, 16.1) than in Whitten's medium (haploids, 35.7; diploids, 40.1; P < 0.01), suggesting that the number of nuclei in blastocysts was affected by the culture medium.     

Mating system and gene flow in the red seaweed Gracilaria gracilis: effect of haploid-diploid life history and intertidal rocky shore landscape on fine-scale genetic structure

The impact of haploid-diploidy and the intertidal landscape on a fine-scale genetic structure was explored in a red seaweed Gracilaria gracilis. The pattern of genetic structure was compared in haploid and diploid stages at a microgeographic scale (< 5 km): a total of 280 haploid and 296 diploid individuals located in six discrete, scattered rock pools were genotyped using seven microsatellite loci. Contrary to the theoretical expectation of predominantly endogamous mating systems in haploid-diploid organisms, G. gracilis showed a clearly allogamous mating system. Although within-population allele frequencies were similar between haploids and diploids, genetic differentiation among haploids was more than twice that of diploids, suggesting that there may be a lag between migration and (local) breeding due to the long generation times in G. gracilis. Weak, but significant, population differentiation was detected in both haploids and diploids and varied with landscape features, and not with geographic distance. Using an assignment test, we establish that effective migration rates varied according to height on the shore. In this intertidal species, biased spore dispersal may occur during the transport of spores and gametes at low tide when small streams flow from high- to lower-shore pools. The longevity of both haploid and diploid free-living stages and the long generation times typical of G. gracilis populations may promote the observed pattern of high genetic diversity within populations relative to that among populations.     

Differentiation of haploid and dihaploid rape plants at the cytological and morphological levels

Some cytological and morphological features of haploid and dihaploid winter rapó plants obtained via the anther cultivation approach have been studied. It was shown that in haploid plants the number of chloroplasts in stomatal guard cells, the size of the stomatal guard cells themselves were much smaller, and the number of stomata per square unit was greater than in doubled haploids and diploids. Haploids were also characterized by smaller sizes of petals and anthers and, in general, a smaller flower as compared to dihapliods and diploids.     

Haploidy, diploidy and evolution of antifungal drug resistance in Saccharomyces cerevisiae

We tested the hypothesis that the time course of the evolution of antifungal drug resistance depends on the ploidy of the fungus. The experiments were designed to measure the initial response to the selection imposed by the antifungal drug fluconazole up to and including the fixation of the first resistance mutation in populations of Saccharomyces cerevisiae. Under conditions of low drug concentration, mutations in the genes PDR1 and PDR3, which regulate the ABC transporters implicated in resistance to fluconazole, are favored. In this environment, diploid populations of defined size consistently became fixed for a resistance mutation sooner than haploid populations. Experiments manipulating population sizes showed that this advantage of diploids was due to increased mutation availability relative to that of haploids; in effect, diploids have twice the number of mutational targets as haploids and hence have a reduced waiting time for mutations to occur. Under conditions of high drug concentration, recessive mutations in ERG3, which result in resistance through altered sterol synthesis, are favored. In this environment, haploids consistently achieved resistance much sooner than diploids. When 29 haploid and 29 diploid populations were evolved for 100 generations in low drug concentration, the mutations fixed in diploid populations were all dominant, while the mutations fixed in haploid populations were either recessive (16 populations) or dominant (13 populations). Further, the spectrum of the 53 nonsynonymous mutations identified at the sequence level was different between haploids and diploids. These results fit existing theory on the relative abilities of haploids and diploids to adapt and suggest that the ploidy of the fungal pathogen has a strong impact on the evolution of fluconazole resistance.