银鲫肌酸激酶M3-CK cDNA的克隆及其表达特征

用抑制性差减杂交结合SMART cDNA合成和RACE—PCR技术克隆到雌核发育银鲫(Carassius auratus gibelio)肌酸激酶M3-CK基因的全长cDNA。银鲫M3-CK cDNA全长1551bp，编码380个氨基酸，与普通鲤鱼(cyprinus carpio)M3-CK的氨基酸序列同源性高达95％。种系分析表明，银鲫M3-CK与其它脊椎动物的肌肉型肌酸激酶聚为较近的一支，与鲤鱼的M3-CK聚在一起，与脑特异型肌酸激酶及线粒体型肌酸激酶分歧较大。虚拟Northern杂交显示银鲫M3-CK基因在胚胎发育中差异表达。RT—PCR表明，银鲫M3-CK基因在成熟卵母细胞和胚胎发育早期可检测到少量的转录产物，在胚胎发育期间从肌肉效应期开始转录，并一直持续表达。组织RT—PCR表明，银鲫M3-CK基因只在心脏和肌肉表达。     

Organization of specific DNA sequence elements in the region of the replication origin and matrix attachment site in the chicken alpha-globin gene domain.

Summary The distribution of specific DNA sequence elements in a 2.9 kb HindIII fragment of chicken DNA containing the replication origin and the upstream matrix attachment site (MAR) of the -globin gene domain was investigated. The fragment was shown to contain a CR1-type repetitive element and two stably bent DNA sequences. One of them colocalizes with the previously described MAR element and with the recognition site for a proliferating-cell-specific, DNA-binding protein. The melting pattern of a set of subfragments of the region proved to be non random. No correlation between the distribution of readily melting sequences and bent DNA was found. The possible importance of curved, low-melting and repetitive DNA sequences for the organization of the upstream boundary of the -globin gene domain and the function of the replication origin is discussed.     

The replication origin of proplastid DNA in cultured cells of tobacco

Summary When tobacco suspension culture line BY2 cells in stationary phase are transferred into fresh medium, replication of proplastid DNA proceeds for 24 h in the absence of nuclear DNA replication. Replicative intermediates of the proplastid DNA concentrated by benzoylated, naphthoylated DEAE cellulose chromatography, were radioactively labelled and hybridized to several sets of restriction endonuclease fragments of tobacco chloroplast DNA. The intermediates hybridized preferentially to restriction fragments in the two large inverted repeats. Mapping of D-loops and of restriction fragment lengths by electron microscopy permitted the localization of the replication origin, which was close to the 23S rRNA gene in the inverted repeats. The replication origins in both segments of the inverted repeat in tobacco proplastid DNA were active in vivo.     

Utilization of grass carp faeces by the IsopodAsellus aquaticus (L.) in the laboratory

Grass carp (Ctenopharyngodon idella Val) faecal pellets derived fromElodea nutallii consumption were efficiently utilized by the detritivoreAsellus. Immature and adult individuals of 2.1–3.2 mm and 4.9–6.0 mm respectively, exhibited a high mean specific growth (9.03%/day and 3.33%/day) when offered faecal pellets as food during two weeks experimental trials. Individuals of the same groups, when fed onElodea which had been mechanically fragmented to simulate the macerating action of the grass carp pharyngeal teeth, grew at rates (9.57%/day and 4.06%/day) not significantly different from those fed on faecal pellets. However, the growth rates of animals fed on freshElodea (6.40%/day and 2.23%/day) were significantly lower than in the above trials, indicating that the morphological destruction of the plant tissue could be responsible for the higher observed growth. The control trials, including unfed animals, showed negative growth (– 0.49%/day and – 0.48%/day).Grass carp herbivory makes a new food resource available to benthic invertebrates by converting fresh plant material to small plant fragments.     

Cryptosporidium anserinum sp. n. (Sporozoa) in a Domestic Goose Anser anser L., from Iowa

SYNOPSIS. Cryptosporidium anserinum sp. n. is described in the large intestinal mucosa of a domestic goose, Anser anser L., from Iowa. Ultrastructural studies revealed schizonts containing 4 merozoites and macrogametes and schizonts with characteristic attachment zones and double membranes. The only lesion associated with infection was shortening of the intestinal microvilli.     

Polymorphism of transferrin in carp (Cyprinus carpio L.): Genetic determination,isolation, and partial characterization

Seven transferrin variants (A, B, C, D, E, F, and G) have been found in carp sera (Cyprinus carpio L.). Genetic analysis involves five variants and agrees with the hypothesis of simple codominant autosomal inheritance at one transferrin (Tf) locus in spite of the fact that the carp is a tetraploid in relation to other species of the same family. Carp populations from three regions were studied which differed in gene frequencies. Individual populations were in Hardy—Weinberg equilibrium. The polymorphism of carp transferrins can be used for the identification of offspring of single parent pairs, stocked in one pond. Transferrins have been isolated and characterized. Homozygous phenotypes comprised four iron-binding components differing in electrophoretic mobility. This heterogeneity is not caused by sialic acid, which is absent. Amino acid composition, content of hexoses (1 mole/mole of protein) and hexosamines (1 mole/mole of protein), molecular weight (70,000), and the isoelectric point (5.0) have been determined. No N-terminal amino acid could be detected.     

Sind Farne Kormophyten? Eine Alternative zur Telomtheorie

Modern ideas concerning cormophyte phylogeny are strongly influenced by the telome theory. Erect growth, radial symmetry, dichotomy, protostely and eusporangial structure are considered to be primitive features. Yet, the cormus needs redefinition. TheHypolepidaceae (s. str.) are shown to have rather a two-dimensional thallus than a three-dimensional cormus. Their so-called rhizome develops a continuous areophore margin which is connected with the margin of the fronds. The longitudinally inserted fronds and branches are produced by the terminal rhizome meristem which itself grows in many respects like the apical frond meristem. The rhizomes ofDennstaedtiaceae and theDavallia-type of rhizomes are intermediate between thisHypolepis-type and the true cormus-type. TheHypolepis-type is compared with fern prothalli. Under perhumid tropical conditions higher land plants may have evolved from small, creeping, two-dimensional fern prothallium-like progenitors with isomorphous gameto- and sporophytes.

Vorgetragen auf der Morphologentagung in Zürich 1975.     

二龄草鱼肠炎病的研究

本文从细菌学、血清学、鱼体免疫以及药物治疗等几个方面,阐明了点状产气单胞菌是二龄草鱼肠炎病的病原菌。另外还对这种细菌特性及其致病方式进行了讨论,并对该病的诊断提供了方法。     

性成熟草鱼卵巢发育的年周期变化

产卵前的卵巢同时含有大量4时相卵母细胞及少量2时相和3时相卵母细胞。产后2时相及3时相卵母细胞增多而4时相卵母细胞骤减,8月份4时相卵母细胞的数量又增多,约占卵巢体积的80％,及至11月份其数量又下降。自11月至翌年1月,卵巢中3时相卵母细胞增多而4时相卵母细胞则消失不见。至2月份,新的4时相卵母细胞又开始出现并逐渐增多。性成熟草鱼的卵巢以如此规律周而复始地产生成熟的卵子。卵巢中卵母细胞的发育是不同步的。但在产卵前有大量的3时相卵母细胞向4时相演化,同时有为数不少的发育中的2时相卵母细胞存在。产后卵巢中亦同时存在不同发育时期的卵母细胞。     

几种鱼类细胞对草鱼呼肠孤病毒敏感性的研究

比较研究了鲫鱼异倍体细胞系(CAB-80)、团头鲂尾鳍细胞系(BCC)、大鳞副泥鳅雌核发育单倍体胚胎细胞系(PHG)、草鱼胚胎细胞系(GCE)、草鱼尾鳍细胞系(GCRF-2)、草鱼肾细胞系(GCK-84)及其四个克隆对草鱼呼肠孤病毒(GCRV)的敏感性。证实了这些细胞(PHG除外)在不同程度上对GCRV敏感,其中以GCK-84的敏感性最强。这表明,在体外培养条件下,GCRV并无严格的种族特异性。用经GCK-84传代的病毒感染草鱼种,能复制出典型的出血病症状。用GCK-84检测了病毒在GCK-84、GCRF-2、CAB-80、BCC和PHG中的滴度(TCID_(50/ml)),其值分别为8.24,7.36,2.90,2.15和1.33。4个克隆与肾细胞系对病毒的敏感程度亦不尽相同,其滴度在6.3到9.32之间变化。上述结果对细胞工程抗病育种预示有较大的潜在意义。在电镜下可见GCRV对被感染的细胞造成了严重的破坏。病毒为平均直径58nm的球形颗粒,具有一个高度电子密度的核心,平均直径约为38nm。病毒在细胞中的分布方式有三种:即散布于细胞质中的、呈晶格状包于一膜状结构中的和整齐或不整齐地聚集在一起但无膜包裹的。