A Service for Human Chromosome Studies in Saskatchewan

A service has been developed in Saskatchewan to make available the results of studies of human chromosomes, the material being forwarded to the laboratory by local transport facilities. During the first year of this project chromosome studies were requested for five doubtful cases of trisomy-21 (two were found to be normal) and for 20 definite cases of trisomy-21 in young patients (two had translocations but the parents of both these children had normal karyotypes). Eleven confirmed cases of Turner''s syndrome, two of Klinefelter''s syndrome, and one each of the D and E syndromes were also studied. The largest group for which studies were requested comprised 36 patients with mental retardation; only two abnormal karyotypes were encountered in this group.     

粪产碱菌（Alcaligenes faecalis）吸收氢和同化CO2的特性

应用同位素氚(T_2)和~13C(~13CO_2),证明了水稻联合固氮菌——粪产碱菌A—15是一种含有吸氢酶的兼性化能自养细菌,具有较强的吸氢能力,吸氨酶活性可达到13.11μmol H_2 ml~(-1) cultureh~(-1);同时,它还可利用H_2为能源同化CO_2营化能自养生活,其RuBPC活性为24.65 nmolCO_2 mg~(-1) protein min~(-1)。无论在自养还是异养条件下,H_2都支持、并促进固氮活性。粪产碱菌培养在N_2条件下比在NH_4~ 条件下能积累更多的多聚-β羟基丁酸(PHB)。     

水稻、小麦、油菜和烟草细胞质雄性不育系统中组分Ⅰ蛋白的比较分析

组分Ⅰ蛋白(RuBP羧化酶/加氧酶)的生物合成系由叶绿体基因和细胞核基因共同控制,所以,被作为研究细胞质遗传的标记。本实验用免疫化学和氨基酸成分分析等方法,对水稻(珍汕97)、小麦(繁7)、油菜(湘矮早)和烟草(G28)的细胞质雄性不育系及其保持系的组分Ⅰ蛋白作了比较,同时对不同作物的组分Ⅰ蛋白也作了免疫鉴定。结果表明,细胞质雄性不育系及其保持系的组分Ⅰ蛋白差异不大,但是,四种不同作物的组分Ⅰ蛋白之间有明显差异。     

油盘孢属和泽田外担菌的研究

寄生于樟、阴香和肉桂等植物上的泽田外担菌和油盘孢属真菌,几十年来分类上存在许多不同看法,或全部归泽田外担菌,或全部归油盘孢属,把此二类不同真菌混淆起来,造成名称混乱。本文通过形态学的研究,表明泽田外担菌与油盘孢属的区别是:泽田外担菌具担子层,担孢子4—8个生担子上,寄主是樟树;而油盘孢属的孢子生菌丝上,形成孢子堆,寄主是阴香和肉桂等植物。     

组胺H2受体拮抗剂对骨髓造血重建的影响

用组胺H_2受体拮抗剂(甲氰咪胍或呋喃硝胺)处理正常和亚致死量γ-射线照射小鼠,探讨正常体内造血和再生骨髓中造血重建与组胺受体的关系。发现非毒性剂量的甲氰咪胍对正常小鼠骨髓多能造血干细胞(CFU-s)无抑制作用,但可抑制小鼠体内粒单系祖细胞(CFU-GM)的生长和亚致死量照射后CFU-s产率的恢复。组胺可能与骨髓的再生有关,组胺H_2受体拮抗剂可抑制骨髓的造血重建。     

氨甲酰胆碱和Impromidine对CFU—S细胞周期的影响

正常情况下处于S期的CFU-S比例低于10％。氨甲酰胆碱(Cach 10~(-13)—10~(-9)mol/L)和Impromidine(Impro 10~(-9)—10~(-4)mol/L)在体外与小鼠骨髓细胞短时培育后,增加了CFU-S对细胞毒剂羟基脲的敏感性。反应最大时,9d和13dCFU-S的减少率分别是32.8和60.6％(Cach)以及38.4和49.5％(Impro)。这种效应可分别被胆碱能N受体阻断剂筒箭毒(10~(-6)mol/L)和组胺H_2受体阻断剂甲氰咪呱(10~(-6)mol/L)所阻断,表明9d和13d CFU-S表面胆碱能N受体和组胺H_2受体的密度或活性存在差别,再次证实了CFU-S是一个不均一的细胞群。     

Nucleotide sequence and expression of cheF, an essential gene for chemotaxis in Bacillus subtilis.

The cheF gene, which is involved in chemotaxis in Bacillus subtilis, has been cloned, expressed, and sequenced. This gene is contained in a 0.7-kilobase PstI DNA fragment that was isolated from a lambda Charon 4A B. subtilis chromosomal DNA library. This fragment was subcloned into the expression vector pSI-1 and shown to complement the cheF mutation both for chemotaxis and for methanol production in response to the addition of attractants. Plasmid-encoded DNA expression in B. subtilis maxicells indicated that a membrane-associated polypeptide of 20-kilodaltons was expressed from this 0.7-kilobase DNA. The nucleotide sequence of this DNA fragment was determined, and an open reading frame capable of encoding a putative 175-amino-acid protein (Mr 20,002) was identified. In an effort to understand the function of the cheF protein, the dosage of the cheF gene product was varied by altering the concentration of IPTG (isopropyl-beta-D-thiogalactopyranoside) during growth. In the presence of high concentrations of IPTG, chemotaxis was inhibited and methanol production was impaired.     

华南绒茧蜂属二新种（膜翅目：茧蜂科）

本文报道采自广西和江西的绒茧蜂属二新种。模式标本存于湖南农学院昆虫标本室。1.黄足绒茧蜂Apanteles vitellinipes,新种(图1～4) 雌 体黑色。触角柄节、梗节、下颚须、翅基片、足(包括基节)、腹部第一背板基部凹陷部分、第1～3背板侧膜边缘和产卵管黄色;触角鞭节、前翅前缘脉、翅痣、痣后脉、产卵管鞘深褐色;其它翅脉褐色。     

环状病毒M14 dSRNA基因组的进一步研究

M14病毒是1981年从北京郊区捕获的三带喙库蚊中分离获得。其生物学、形态学和理化特性均符合呼肠孤病毒科环状病毒的特点。聚丙烯酰胺凝胶电泳将其dsRNA基因组分离成11条区带。但最近的进一步研究发现,它是由12个片段的RNA组成。又用猴轮状病毒SA11株作为标准,测定了每个片段的分子量。 白纹伊蚊细胞C6/36纯系,由日本长畸大学热带医学研究A.Igarashi教授惠赠,并照他的方法培养传代。     

不同底物与固氮酶及其钼铁蛋白相互作用的荧光光谱分析

 本文研究了不同底物(N_2,H_2,N_2O,NaN_3,C_2H_2)对棕色固氮菌固氮酶及其钼铁蛋白荧光光谱的影响。结果表明,上述底物均能络合在钼铁蛋白及固氮酶上,但络合程度不同,从而为固氮酶系统有多个不同的底物络合中心,底物络合中心在钼铁蛋白分子上,铁蛋白对钼铁蛋白有变构作用,提供了光谱学证据。