泰国森林植被的主要类型

泰国的主要森林植被大致可分为常绿林和落叶林两大类（森林植被型组）和热带雨林、山地常绿林、半常绿林、针叶林、红树林、干旱龙脑香林及落叶混交林等七亚类（森林植被型）．本文简要阐述了各类森林的地理分布、层次结构和主要树种组成．     

不同时期分离的淋病奈瑟菌对5种抗生素的敏感性研究

目的：研究杭州市不同时期分离的林病奈瑟菌对5种抗生素的敏感性。方法：用琼脂烯释法对门诊1998年7月～2001年10月分离的285株淋病奈瑟菌进行青霉素、四环素、壮观霉素、氧氟沙星及头孢曲松的最小抑菌浓度（MIC）测定,并就PPNG株和non-PPNG株菌的MIC值进行了比较。结果：青霉素、四环毒等5种抗生素MIC值2001年～1998年两者之间比较,青霉素、四环素等5种抗生素MIC值2001年与1998年两者之间比较,除壮观霉素没有变化外,其余都有显著变化,而氧氟沙星变化最大,PP-NG菌株与非PPNG株菌MIC值除氧氟沙星外均存在差异。结论：表明了杭州市淋病奈瑟菌5种抗生素耐药性变迁,以便为临床选择用药提供依据。     

中国和泰国狗牙花属植物订正

<正> 狗牙花属本来的原始学名是1737年美洲加勒比岛(Caribbean Isl.)一个修道士勃隆米尔(Charles Plumier),将一种生在山上的植物作为属名Tabernaemontana来命名的,后来被林柰氏1753年编写的植物种志所列入。该属自创立以来,迄今已达二百六十年历史了,在     

培菲康双歧三联活菌制剂中三株菌对抗菌药物敏感性检测

目的：检测培菲康活菌制剂中双歧杆菌,嗜酸乳杆菌与粪链球菌三株菌对30种抗菌药物的敏感性。方法：用纸片琼脂扩散法（disc agar diffusion,即Kirby-Bauer法）和微量稀释法（microdilution bro9th method)进行检测。结果：这三株菌对大多数抗菌药物敏感,对少数抗菌药物耐受。与文献报导相似,这三株菌与相应的国际参考菌株及临床菌株比较,没有发现明显耐药变异。结论：为避免抗菌药物对双歧三联活菌制剂功效的影响。每天两药宜分开时间服用。服用双歧三联活菌不会引起耐药性的扩散。     

SYNTHESIS OF CHLOROPLAST DNA IN ISOLATED CHLOROPLASTS

Chloroplasts isolated from Euglena gracilis incorporated both tritiated thymidine 5'-triphosphate and tritiated deoxyadenosine 5'-triphosphate into an acid-stable fraction. The incorporation was dependent on the presence of all four deoxynucleoside triphosphates and was sensitive to treatment with deoxyribonuclease and actinomycin D. It was demonstrated that bacterial contamination could not account for the incorporation of label. Extraction of DNA from the chloroplasts and subsequent density gradient centrifugation of the DNA in CsCl₂ showed that the incorporation was into chloroplast DNA (ρ = 1.686) of high molecular weight.     

AN ANALYSIS ON THE TROPISM IN HVJ (SENDAI VIRUS) INFECTION: MANIFESTATION OF HIGH VIRAL SUSCEPTIBILITY IN SPREADING CULTURES OF ISOLATED ALLANTOIC EPITHELIAL CELLS OF THE CHICK EMBRYO

By culturing pure allantoic epithelial cells separated from the chorioallantoic membrane of a 10-day-old chick embryo, sheets of monolayered epithelial cells were obtained and maintained for at least one week. These cells were highly susceptible to infection with HVJ (Sendai virus) in vitro . In similarly cultured mesenchymal cells of the chorioallantoic membrane, the susceptibility was found to be very low. It was concluded that the tropism observed in HVJ infection in vitro can be explained by differences in the susceptibility to HVJ among various cell types.     

GEOGRAPHIC DIFFERENCES IN SEXUAL REASSORTMENT IN RNA PHAGE

The genetic structure of natural bacteriophage populations is poorly understood. Recent metagenomic studies suggest that phage biogeography is characterized by frequent migration. Using virus samples mostly isolated in Southern California, we recently showed that very little population structure exists in segmented RNA phage of the Cystoviridae family due to frequent segment reassortment (sexual genetic mixis) between unrelated virus individuals. Here we use a larger genetic dataset to examine the structure of Cystoviridae phage isolated from three geographic locations in Southern New England. We document extensive natural variation in the physical sizes of RNA genome segments for these viruses. In addition, consistent with earlier findings, our phylogenetic analyses and calculations of linkage disequilibrium (LD) show no evidence of within‐segment recombination in wild populations. However, in contrast to the prior study, our analysis finds that reassortment of segments between individual phage plays a lesser role among cystoviruses sampled in New England, suggesting that the evolutionary importance of genetic mixis in Cystoviridae phage may vary according to geography. We discuss possible explanations for these conflicting results across the studies, such as differing local ecology and its impact on phage growth, and geographic differences in selection against hybrid phage genotypes.     

INDUCTION OF XYLEM ELEMENTS IN ISOLATED COLEUS PITH

Small pith explants from the fifth internode of Coleus blumei were placed on a defined medium supplemented with different concentrations of indoleacetic acid (IAA). With all levels of IAA tissue growth was slight; however, when the medium contained more than 10^-7 m IAA, xylem elements developed after 11-14 days. Omission of sucrose from the medium prevented this differentiation of xylem elements. Isolated xylem cells or small nodules were most common, but long strands were also seen. The merits of the Coleus system for study of plant-cell differentiation are discussed.     

EFFECT OF PLASTOCYANIN ON PHOTOPHOSPHORYLATION IN ISOLATED CHLOROPLASTS

The effect of addition of plastocyanin on photophosphorylationin isolated chloroplasts was studied in comparison with itseffect on photoreduction. Catalytic amounts of added plastocyaninstimulated the HILL reaction with NADP as oxidant, but the photophosphorylationcoupled to this reaction was not influenced by the additionof plastocyanin. The addition of NH₄+ or the complete phosphorylatingsystem did not affect the plastocyanin-induced increase in rateof the photoreduction. The rate of photoreduction of NADP, FMN,or indigo carmine in the presence of DPIP and ascorbate wasmuch accelerated by added plastocyanin, but these reactionswere not coupled to ATP formation. As reported earlier, isolated chloroplasts can utilize plastocyaninas oxidant in the HILL reaction. This reaction was found tobe accompanied by ATP formation, but the efficiency in thiscase was somewhat lower than in photophosphorylation coupledto the HILL reaction with the usual oxidants. The possible mechanism of these reactions is described brieflyand a scheme for reactions of plastocyanin in the electron transferin chloroplasts is presented. (Received July 20, 1965; )     

SEROLOGY AND TRANSDUCTION IN STAPHYLOCOCCAL PHAGE.

Dowell, C. E. (The University of Texas, Dallas) and E. D. Rosenblum. Serology and transduction in staphylococcal phage. J. Bacteriol. 84:1071-1075. 1962.-A triply lysogenic strain of Staphylococcus aureus was shown to carry a serological group B phage capable of transduction. Three typing phages (53, 80, 42D), either belonging to serological group B or having a close association with it, were also shown to have transducing ability. A rapid screening method was used to isolate two new transducing phages, both of which belonged to serological group B. Propagating strain 42B/47C was found to carry a transducing phage that was neutralized by both group B and group F antisera. Nine other phages belonging to serological groups other than group B did not have generalized transducing ability, nor did three group B typing phages that were atypical in their calcium requirement. It was postulated that transducing ability is associated with staphylococcal phages of serological group B and with related phages of group F.