山西蒲县薛关细石器

本文记述了采自山西蒲县薛关的一批细石器。这批石器属于以楔状石核为特征的典型细石器技术传统。它的发现,对探索旧石器时代晚期人类在吕梁山一带劳动、生息状况,对进一步探讨我国华北地区各细石器文化之间的相互关系,都有一定的意义。     

小麦不同发育时期酯酶、过氧化物酶同工酶酶谱 的比较研究

休眠干种子,浸种8小时和24小时萌动胚酯酶酶谱的特点是:酶带数较多,并且活力高的酶带基本上都集中在快带区与慢带区。一叶期、二叶期、三叶期酶谱的特点是酶带数大为减少,并且活力较低,在慢带区变化尤大。分蘖期是研究的九个发育时期中,酶带最少而且酶活力最低的一个发育时期。剑叶期酶谱与分蘖期相似,但酶带数和酶活力都有所提高。开花后15—18天的乳熟种子的酶谱有较大变化,酶带数显著增多,酶活力增强;并且在这一发育时期,不同材料间的差异容易显示出来。过氧化物酶同工酶酶谱,在不同发育时期是有差别的,但差异不及酯酶大。休眠干种子和浸种8小时种胚的过氧化物酶酶带数目较少而且活力低。但浸种24小时,酶带数显著增多而且活性较强,显色较深。一叶期、二叶期,三叶期的酶带数都比较多而强,至分蘖盛期酶带数有所下降,剑叶期又有所提高,乳熟期种子出现酶带数和酶活性都比较多而强。     

A Col E1 hybrid plasmid containing Escherichia coli genes complementing d-xylose negative mutants of Escherichia coli and Salmonella typhimurium

The Clarke and Carbon bank of Col El - Escherichia coli DNa hybrid plasmids was screened for complementation of d-xylose negative mutants of E. coli. Of several obtained, the smallest, pRM10, was chosen for detailed study. Its size was 16 kilobases (kb) and that of the insert was 9.7 kg. By transformation or F'-mediated conjugation this plasmid complemented mutants of E. coli defective in either D-xylose isomerase or D-xylulose kinase activity, or both. The activity of D-xylulose kinase in E. coli transformants which bear an intact chromosomal gene for this enzyme was greater than that for the host, due to a gene dosage effect. The plasmid also complemented D-xylose negative mutants of Salmonella typhimurium by F'-mediated conjugation between E. coli and S. typhimurium. Salmonella typhimurium mutants complemented were those for D-xylose isomerase and for D-xylulose kinase in addition to pleiotropic D-xylose mutants which were defective in a regulatory gene of the D-xylose operon. In addition, the plasmid complemented the glyS mutation in E. coli and S. typhimurium. The glyS mutant of E. coli was temperature sensitive, indicating that the plasmid carried the structural gene for glycine synthetase. The glyS mutation in E. coli maps at 79 min, as do the xyl genes. The behaviour of the plasmid is consistent with the existence of a d-xylose operon in E. coli. The data also suggest that the plasmid carries three of the genes of this operon, specifically those for D-xylose isomerase, D-xylulose kinase, and a regulatory gene.     

中国贝母属(Fritillaria)7种植物的核型研究

通过对7种国产贝母属（Fritillaria）植物的染色体核型进行观察和研究,报道了小白花贝母（F.albidoflora Duan&Zheng）、川贝母（F.cirrhosa Don）、伊贝母（F.pallidiflora Schrenk ex Fischer&Meyer）、华西贝母（F.sichuanica Chen）、托里贝母（F.tortifolia Duan&Zheng）、新疆贝母（F.walujewii Regel）、裕民贝母（F.yuminensis Duan）等7种植物的染色体数目及核型,其中3种为首次报道。结果显示,7种国产贝母属植物的核型均具有高度不对称性。此外,小白花贝母与已报道的黄花贝母（F.verticillata Willdenow）的核型存在明显差异,提示Flora of China将小白花贝母归并入黄花贝母的分类处理可能并不恰当,二者的关系需进一步研究。     

Effects of disinfectants on Campylobacter jejuni

Because of the increasing recognition that Campylobacter jejuni is an important enteric pathogen of humans, we studied the effects of widely used disinfectants on the viability of this organism. At an inoculum size of 10(3) to 10(4) CFU/ml, 1.25 mg of hypochlorite per liter killed three strains within 1 min. At an inoculum size of 10(6) to 10(7) CFU/ml, 5 mg of hypochlorite per liter killed three strains within 15 min. Killing of similar concentrations of C. jejuni and Escherichia coli by hypochlorite was approximately the same. At the high inoculum, 0.15% phenolic compound, 10 mg of iodophor per liter, 1:50,000 quaternary ammonium compound, 70% ethyl alcohol, and 0.125% glutaraldehyde killed all three strains within 1 min. These studies demonstrate that, under the conditions we tested (pH 7.0; 24 to 26 degrees C), the recommended standard concentrations of disinfecting agents are adequate to destroy C. jejuni.     

Difference in susceptibility of arginine-vasopressin and oxytocin to aminopeptidase activity in brain synaptic membranes

Arginine-vasopressin and oxytocin, peptides which serve as putative precursors for neurotrophic fragments, were digested in the presence of the respective ¹⁴C-Tyr²- and ${}^{14}\text{C-GlyNH}{}_2{}^9\text{-labeled}$ nonapeptides with a purified synaptic membrane preparation of rat brain. In this preparation aminopeptidase activity predominates in the conversion of these peptides. The disappearance of intact peptide and the release of free ¹⁴C-Tyr and ¹⁴C-GlyNH₂ was followed simultaneously with time by HPLC. Oxytocin was about four times more resistant to proteolysis than arginine-vasopressin as measured by slower disappearance of intact oxytocin, and reflected by the slower release of ¹⁴C-Tyr, but not of ¹⁴C-GlyNH₂ from oxytocin. Comparison of degradation rates of structure analogues showed that peptides having Ile in position 3, as oxytocin, were more resistant than analogues having Phe in position 3, as arginine-vasopressin. The data demonstrate that arginine-vasopressin and oxytocin differ markedly in susceptibility to the aminopeptidase activity in brain synaptic membranes, and indicate that this difference resides primarily in the amino acid residue in position 3. It is suggested that the difference in susceptibility may affect the pattern of neurotrophic metabolites in brain.     

黑胸大蠊（Periplaneta fuliginosa）病毒的分离及某些特性

从黑胸大蠊(Periplaneta fuliginosa)自然罹病的虫尸中分离得到一株非包涵体病毒。将病毒悬液均匀拌入无菌饲料并供食154～169日龄黑胸大蠊健康若虫时,能使其感染、发病,死亡率可达98％以上。在电子显微镜下观察时,病毒为球形二十面体颗粒,直径约23nm。病毒悬液具有典型核蛋白紫外吸收光谱。病毒用DNase和RNase处理并经吖啶橙染色、二苯胺和苔黑酚试验及甲醛反应证明:该病毒含有单链DNA。以上特性与细小病毒科的特征有点类似。     

正廿面体病毒的三角形剖分数和壳粒数公式的推导

本文对p=h~2+hk+k~2,T=pf~2,C=10T+2和C=10p(n-1)~2+2几个公式进行了新的推导和计算,并对其公式间的关系和每个参数的数学含义作了说明,进而澄清了一些模糊认识,加深了对公式的理解和运用。