Chromosomal aberrations induced in barley by LSD

Seeds of hulled barley (Hordeum vulgare) were germinated and then treated with LSD. Preparations of squashed root tips stained with Feulgen revealed extensive chromosomal aberrations, most of which were chromosome breaks. Nearly half of the breaks occurred in the region of the primary constriction.     

家禽黏膜免疫研究进展

对家禽黏膜免疫系统的组成、特点、功能进行了具体的阐述 ,并对家禽黏膜免疫反应所涉及到的免疫细胞、免疫反应过程、黏膜免疫反应的特点进行了详细介绍 ,在此基础上进一步阐述了家禽黏膜免疫在抗感染中的机制、作用以及分泌型免疫球蛋白A(sIgA)与家禽黏膜免疫的关系。     

鸡球虫亚单位苗研究进展

目前药物治疗和活菌预防对球虫病来说存在许多问题，所以研究者的工作重点主要转移到重组亚单位苗的开发上，并且已经克隆出许多抗原。本文从母源亚单位苗和重组亚单位苗两方面对球虫进行了阐述。特别是对柔嫩艾美耳球虫和堆型艾美耳球虫的重组抗原的研究现状进行了较为详细的综述。     

Chromosomal breakage induced by extracts of human allogeneic lymphocytes

A high frequency of chromosomal breakage and rearrangement has been found in fibroblasts treated with extracts of allogeneic human lymphocytes. The fact that these changes were not observed when extracts of autologous lymphocytes were tested indicates that mechanisms involving self-recognition are operative. Abnormalities, such as chromosome lagging and bridges, occurring in anaphase were also served.     

Mutations induced in Tradescantia by small doses of x-rays and neutrons: analysis of dose-Response curves

Dose-response curves for pink somatic mutations in Tradescantia stamen hairs were analyzed after neutron and x-ray irradiation with doses ranging from a fraction of a rad to the region of saturation. The dose-effect relation for neutrons indicates a linear dependence from 0.01 to 8 rads; between 0.25 and 5 rads a linear dependence is indicated for x-rays also. As a consequence the relative biological effectiveness reaches a constant value (about 50) at low doses. The observations are in good agreement with the predictions of the theory of dual radiation action and support its interpretation of the effects of radiation on higher organisms. The doubling dose of x-rays was found to be nearly I rad.     

Toxoplasma from the eggs of the domestic fowl (Gallus gallus)

Toxoplasmata of varying grades of virulence were isolated from eggs laid by clinically asymptomatic hens and from their internal organs. The strains so recovered were identified as Toxoplasna gondii by morphological, serological, cultural, and pathogenic criteria. These findings strongly suggest that toxoplasmosis may be contracted through the eating of raw or undercooked infected eggs.     

自然四倍体泥鳅雄核发育二倍体染色体组构成研究

为探究鱼类雄核发育新途径及自然四倍体泥鳅所产生的配子染色体组构成,采用自然四倍体泥鳅(4n=100)为父本、二倍体泥鳅(2n=50)为母本进行杂交,受精后5 min将受精卵放入3℃水中处理60 min诱导雄核发育二倍体泥鳅,并对其后代的血红细胞核体积、染色体核型、Ag-NORs带型及荧光原位杂交(FISH)信号等进行了研究。结果表明:对照组杂交三倍体泥鳅血红细胞核体积为(38.29±3.14)μm³,处理组雄核发育二倍体泥鳅血红细胞核体积为(27.92±3.58)μm³,二者血红细胞核体积之比为1.37∶1;杂交三倍体泥鳅胚胎染色体数目3n=75,核型公式为15m+6sm+54t,NF=96,雄核发育二倍体泥鳅胚胎染色体数目2n=50,核型公式为10m+4sm+36t,NF=64;杂交三倍体泥鳅胚胎染色体中,在3个染色体短臂的端部检测到3个FISH杂交信号,雄核发育二倍体泥鳅胚胎染色体中,在2个染色体短臂的端部检测到2个FISH杂交信号;杂交三倍体泥鳅染色体和间期核中,呈现出Ag-NORs数目为1~3个,雄核发育二倍体泥鳅胚胎染色体和间期核中,呈现出Ag-NORs数目为1~2个。研究表明,雄核发育二倍体泥鳅的染色体组构成为2套染色体组,表明自然四倍体雄性泥鳅能产生二倍体(2n)配子,该结果为自然四倍体雄性泥鳅是具有4套染色体组的遗传四倍体提供了重要的遗传学证据。     

自然四倍体泥鳅雄核发育二倍体染色体组构成研究

为探究鱼类雄核发育新途径及自然四倍体泥鳅所产生的配子染色体组构成,采用自然四倍体泥鳅(4n=100)为父本、二倍体泥鳅(2n=50)为母本进行杂交,受精后5 min将受精卵放入3℃水中处理60 min诱导雄核发育二倍体泥鳅,并对其后代的血红细胞核体积、染色体核型、Ag-NORs带型及荧光原位杂交(FISH)信号等进行了研究。结果表明:对照组杂交三倍体泥鳅血红细胞核体积为(38.29±3.14)μm³,处理组雄核发育二倍体泥鳅血红细胞核体积为(27.92±3.58)μm3,处理组雄核发育二倍体泥鳅血红细胞核体积为(27.92±3.58)μm³,二者血红细胞核体积之比为1.37∶1;杂交三倍体泥鳅胚胎染色体数目3n=75,核型公式为15m+6sm+54t, NF=96,雄核发育二倍体泥鳅胚胎染色体数目2n=50,核型公式为10m+4sm+36t, NF=64;杂交三倍体泥鳅胚胎染色体中,在3个染色体短臂的端部检测到3个FISH杂交信号,雄核发育二倍体泥鳅胚胎染色体中,在2个染色体短臂的端部检测到2个FISH杂交信号;杂交三倍体泥鳅染色体和间期核中,呈现出Ag-NORs数目为1～3个,雄核发育二倍体泥鳅胚胎染色体和间期核中,呈现出Ag-NORs数目为1～2个。研究表明,雄核发育二倍体泥鳅的染色体组构成为2套染色体组,表明自然四倍体雄性泥鳅能产生二倍体(2n)配子,该结果为自然四倍体雄性泥鳅是具有4套染色体组的遗传四倍体提供了重要的遗传学证据。     

达氟沙星对禽霍乱鸡霉形体与大肠杆菌混合感染的药效学研究

为研究国产新兽药达氟沙星对人工感染禽霍乱及鸡败血霉形体与大肠杆菌合异感染的药效学 ,每个治疗试验随机分为达氟沙星三个不同剂量组、恩诺沙星对照组、阳性对照组和阴性对照组。当感染鸡出现典型症状时 ,达氟沙星三个剂量组、恩诺沙星组分别按每L水 10 0mg、50mg、2 5mg、50mg、混饮用药。结果表明 :达氟沙星三个不同剂量组、恩诺沙星对照组连续用药 4天 ,对禽霍乱的治愈率分别是 93 3%、93 3%、80 %、86 7% ,而感染对照组的死亡率为 6 6 7% ;达氟沙星三个不同剂量组、恩诺星沙对照组连续用药 5天 ,对鸡败血霉形体与大肠杆菌合异感染的治愈率分别是 98%、92 5%、75%、85% ,抗体阳性反应率分别为 0、10 %、4 0 %、30 % ,平均气囊损伤计分分别是 0 4、0 6、1 2、1 0 ,而感染对照组的死亡率为 4 0 % ,抗体阳性反应率为 10 0 % ,平均气囊损伤计分是 7 4。     

Interaction of chromatid breaks produced by x-rays and radiomimetic compounds

The results of combination treatments of the roots of Vicia faba with certain radiomimetic compounds (8-ethoxycaffeine, maleic hydrazide, beta-propiolactone, potassium cyanide) and x-ray as well as combination treatments of certain radiomimetic compounds with one another were observed to determine whether interaction will occur between chromosomal breaks induced by different agents. Interaction was observed between breaks induced by x-rays and all of the breaks induced by chemicals but not between breaks induced by any two chemicals. The results are discussed in terms of possible breakage bond differences and the effects of temporal and spatial differences in breaks induced by different agents.     

Sequence-directed DNA translocation by purified FtsK

DNA translocases are molecular motors that move rapidly along DNA using adenosine triphosphate as the source of energy. We directly observed the movement of purified FtsK, an Escherichia coli translocase, on single DNA molecules. The protein moves at 5 kilobases per second and against forces up to 60 piconewtons, and locally reverses direction without dissociation. On three natural substrates, independent of its initial binding position, FtsK efficiently translocates over long distances to the terminal region of the E. coli chromosome, as it does in vivo. Our results imply that FtsK is a bidirectional motor that changes direction in response to short, asymmetric directing DNA sequences.     

Hereditary autoimmune thyroiditis in the fowl

In the Cornell C strain of White Leghorn chickens, thyroiditis appeared spontaneously. It was characterized by phenotypic changes due to a decrease of thyroxine, histological damage to the thyroid gland, and the presence in the seruim of antibodies to thyroglobulin. Susceptibility to the disease is genetically inherited. Hormonal bursectomy (androgen given to the embryo) suppresses the development of thyroiditis.     

Catalysis of ribosomal translocation by sparsomycin

During protein synthesis, transfer RNAs (tRNAs) are translocated from the aminoacyl to peptidyl to exit sites of the ribosome, coupled to the movement of messenger RNA (mRNA), in a reaction catalyzed by elongation factor G (EF-G) and guanosine triphosphate (GTP). Here, we show that the peptidyl transferase inhibitor sparsomycin triggers accurate translocation in vitro in the absence of EF-G and GTP. Our results provide evidence that translocation is a function inherent to the ribosome and that the energy to drive this process is stored in the tRNA-mRNA-ribosome complex after peptide-bond formation. These findings directly implicate the peptidyl transferase center of the 50S subunit in the mechanism of translocation, a process involving large-scale movement of tRNA and mRNA in the 30S subunit, some 70 angstroms away.     

珍珠鸡人工授精的研究

用电刺激采精方法 ,对 5只雄性成年珍珠鸡进行 2 5只次试验 ,皆获得精液。与按摩采精法相比 ,电刺激采精法采集的精液量 (0 .5 5 m L )显著高于按摩法 (0 .12 m L ) ,平均每次射出的精子总数 (4.2 2亿个 )比按摩采精法 (2 .4 4亿个 )显著增加 ,但精子活率和受精率无显著差异。冷冻试验结果表明 ,精子的活率为 2 0 %～ 5 0 % ,输精结果表明 ,受精率可达 6 0 %。     

利用流式细胞术检测甜菜染色体倍性和DNAC-值

[目的]研究流式细胞技术快速、准确、方便测定甜菜体内染色体倍性和DNAC-值,为甜菜染色体倍性、分子生物学领域的相关研究提供参考依据.[方法]以二倍体M39-8-4嫩叶为材料,以已知基因组的新疆野杏洛浦洪待克为外标,建立适合于甜菜染色体倍性和基因组的流式细胞术测定方法.[结果]经7种常用细胞解离液筛选,Marie's为...