韦氏鳞(虫八)的精子结构(双尾目)

韦氏鳞(虫八)(Lepidocampa weberi)精子为细长的鞭毛精子,成束排列成精索。顶体由三层结构组成;核圆柱形,接于顶体后;鞭毛轴丝微管式为“9+9+2”,9条副微管排列不整齐,集中于轴丝的一侧;两条细长的线粒体衍生物位于顶体、核与轴丝之间,贯穿于精子中部;精子尾部围有大量片层结构。结果表明韦氏鳞(虫八)精子与康(虫八)精子较为接近,但可能比康(虫八)精子更为特化。     

Phenotypically normal transgenic T-cyt tobacco plants as a model for the investigation of plant gene expression in response to phytohormonal stress

The tumour-inducing T-DNA gene 4 (T-cyt gene) of the nopaline Ti plasmid pTiC58 was cloned and introduced into tobacco cells by leaf disc transformation using Agrobacterium plasmid vectors. Tobacco shoots exposed to elevated cytokinin levels were unable to develop roots and lacked apical dominance. Using exogenously applied phytohormone manipulations we were able to regenerate morphologically normal transgenic tobacco plants which differed in endogenous cytokinin levels from normal untransformed plants. Although T-cyt gene mRNA levels, as revealed by dot-blot hybridization data, in these rooting plants were only about half those in primary transformed shoots the total amount of cytokinins was much lower than in crown gall tissue or cytokinin-type transformed shoots as reported by others. Nevertheless the cytokinin content in T-cyt plants was about 3 times greater than in control tobacco plants.Elevated cytokinin levels have been shown to change the expression of several plant genes, including some nuclear genes encoding chloroplast proteins. Our results show that the mRNA levels of chloroplast rbcL gene increase in cytokinin-type transgenic tobacco plants as compared with untransformed plants. Data obtained suggest that T-cyt transgenic plants are a good model for studying plant gene activity in different parts of the plant under endogenous cytokinin stress.     

亚洲象无齿奎隆线虫一新种：（圆形亚目：毛线科）

本文报道作者近年来在石家庄动物园对亚洲象Elephas maximus进行药物驱虫时采集的寄生线虫一新种,无齿奎隆线虫,新种Quilonia edentata sp.nov.,模式标本保存于河北师范大学生物系。     

Obtaining transgenic Solanum tuberosum potato plants with active bacterial genes xyl and T-cyt effecting the phytohormone balance]

The genetic constructions based on integrative vector pGV3850 were used to introduce bacterial genes xyl and T-cyt into potato cells. The transformation was carried out using the leaf-disc method with modifications. A special system for obtaining regenerants from explants of potato in vitro plants or calli has been designed that permitted the selection of transgenic shoots. The presence of the genes in potato genome has been proved by testing the NPTII and glucoisomerase activities. The transgenic plants expressing T-cyt gene differed from the wild type in sharp decrease of the apical dominance.     

二十二种木材对家白蚁天然抗性的室内测定

白蚁蛀蚀不同树种的木材有明显的偏爱性,各种木材抵抗白蚁的蛀蚀能力也有很大差异。如在我国南方,用马尾松作房屋中的木构件,短短几年内就可能遭受白蚁蛀损,而某些抗蚁蛀良好的木材,使用年限超过百年的却不乏其例。研究太材对白蚁的天然抗性能为选择造林和绿化树种,合理用材以及寻找植物性抗白蚁物质提供依据。本工作对广东常见的二十二种本地产和外来树种的木材,用南方危害最大的家白蚁Coptotermes formosanus Shiraki作室内生物测定,并讨论了影响木材抗蚁蛀性的各种因素。     

Influences of medium consistency and shoot density on in vitro shoot proliferation of Populus alba × P. grandidentata

The in vitro shoot proliferation of Populus alba × P. grandidentata was affected by the medium consistency and shoot density, but not by three sizes of vessels. After 4 weeks of culture, the fresh weight and number of shoots per explant on liquid medium were significantly greater than those on agar-solidified medium. In particular, 3.2 shoots, 7 mm or longer per explant, were produced on liquid medium compared with 1.6 shoots per explant or agar-solidified medium. The fresh weight per explant after 4 weeks of culture on liquid medium and agar-solidified medium were 0.68 and 0.25 g, respectively. Increasing the number of shoots per vessel slowed the growth of the explants as measured by fresh weight and the number of shoots produced. There was little difference in the number of shoots produced between vessels with 1 or 2 shoots per vessel, but there were many fewer shoots produced when 3 shoots were placed in each vessel.Journal Paper No. J-11977 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa. Project 2210.     

Typing of Nontypable Staphylococci by Lysogeny

Strains of coagulase-positive staphylococci which were nontypable with the routine typing set of phages could be typed by lysogeny with phage-propagating strains as indicators and with ultraviolet induction. About 10% of the strains could be typed without induction. About 36% of them could be typed by this method when ultraviolet irradiation was used as an inducing agent. The phage groups from which the majority of the nontypable staphylococci originated were easily identified by this method of typing.     

Islet-cell Carcinoma (Zollinger—Ellison Syndrome) with Fulminating Adrenocortical Hyperfunction and Hypokalemia

The production of ACTH-like material by tumours arising in non-endocrine tissue may initiate severe adrenocortical hyperfunction. The pathogenesis and clinical and laboratory features of Cushing''s syndrome associated with such tumours are characteristic. The autonomous production by the tumour of ACTH-like material cannot be suppressed by exogenous corticoids. The onset of clinical symptoms is rapid; muscle wasting, general weakness, thirst and peripheral edema predominate, and the classical signs of Cushing''s syndrome may be absent. High levels of plasma 17-hydroxycorticosteroids and urinary 17-hydroxycorticosteroids and 17-ketosteroids, usually with normal levels of urinary aldosterone, commonly occur. Hypokalemic alkalosis unresponsive to replacement therapy may cause death. In the case reported herein, the intriguing possibility exists that two hormone-like substances were produced by the primary growth and its metastases: one, ACTH-like, to account for the adrenal hyperplasia and Cushing''s syndrome; and another, gastrin-like, giving rise to the ulcerogenic diathesis.     

咖啡碱对椎实螺胚增长的影响

作者采用简单的螺胚生长抑制法,证明软体动物细胞具有DNA复制后修复功能,并受咖啡碱抑制。在没有其他诱变剂的参与下,咖啡碱并不损伤DNA,但也没有保护作用。