Strain of mycoplasma associated with human reproductive failure

A strain of mycoplasma not previously described has been isolated from the chorion, decidua, and amnion of a patient who sustained a spontaneous abortion during the middle trimester. The fetal membranes exhibited an inflammatory reaction, but no evidence of other infectious agents, bacterial or viral, was noted. The T strain identified is not a classical mycoplasma; it differs in growth and nutritional requirements from the T strains previously characterized.     

Fermentation Performance and Characterization of Cold-Adapted Lipase Produced with Pseudomonas Lip35

Strain of Pseudomonas Lip35 producing lipase was isolated in a refrigerator. Lipase production and characterization of this strain were investigated under different conditions. The Pseudomonas was cultivated in shaking flasks in a fermentation medium in various nutritional and physical environments. Lipase production has been influenced by the presence of yeast-extract, soybean powder, NaCl, and Tween-80. Maximum lipase productivity was obtained when the physical environment of the fermentation medium was optimal for 67 h. The production of lipase reached 58.9 U mL-1 The lipase of Pseudomonas Lip35 can be considered to be inducible, but the inducer had little influence on the production of lipase.The lipase was characterized and showed high lipolytic activity from pH 7.5-8.0. The optimum temperature was observed at 20℃ and the thermal inactivation of lipase was obvious at 60℃. The lipase activity was inhibited by K+, stimulated by Ca2+, and thermostability decreased in the presence of Ca2+, therefore the lipase was Ca2+-dependent cold-adapted enzyme.     

Incorporation of unnatural pyrimidine bases into deoxyribonucleic acid of mammalian cells

When a mammalian cell strain was incubated with 5-iododeoxyuridine and 5-bromodeoxyuridine, DNA thymine was partially replaced by the halogen-containing pyrimidines. The extent of incorporation of the unnatural bases increased when amethopterin and hypoxanthine were added to the medium. It is thus evident that the replacement of DNA thymine by selected structural analogs, a phenomenon previously reported for bacterial systems, is applicable to cells of higher organisms.     

Human oocytes: maturation in chemically defined media

Human oocytes from ovarian follicles resume meiosis in F10, a defined medium, in numbers comparable to that obtained in medium containing serum. Several simple Krebs-Ringer media also support maturation, which suggests a similarity of nutritional requirements between human and mouse oocytes. Fewer oocytes reach metaphase II when the investing follicular cells are removed prior to culture.     

Double-stranded ribonuclease coinduced with interferon

Double-stranded (ds) RNA and many viruses are inducers of interferon (IFN), the latter presumably because they contain, or can form, dsRNA. Concomitant with the induction of IFN in chicken embryo cells was the induction of a novel double-stranded ribonuclease (dsRNase), which was released into the medium and continued to accumulate long after IFN production ceased. Only avian cells (chicken, quail, turkey, or duck) expressed high levels of this dsRNase; mammalian, turtle, or fish cells did not. Production of the nuclease was inducer dose-dependent. Optimum pH and cation requirements distinguished it from other dsRNase activities. Degradation of dsRNA was endonucleolytic. Activity resided in a molecule of an Mr of approximately 34,500. Low levels of a single-stranded (ss) RNase activity were inseparable from the dsRNase. The role for a dsRNA-inducible dsRNase released from cells is unknown.     

Fermentation Performance and Characterization of Cold-Adapted Lipase Produced with Pseudomonas Lip35

Strain of Pseudomonas Lip35 producing lipase was isolated in a refrigerator. Lipase production and characterization of this strain were investigated under different conditions. The Pseudomonas was cultivated in shaking flasks in a fermentation medium in various nutritional and physical environments. Lipase production has been influenced by the presence of yeast-extract, soybean powder, NaCI, and Tween-80. Maximum lipase productivity was obtained when the physical environment of the fermentation medium was optimal for 67 h. The production of lipase reached 58.9 U·mL^-1. The lipase of Pseudomonas Lip35 can be considered to be inducible, but the inducer had little influence on the production of lipase. The lipase was characterized and showed high lipolytic activity from pH 7.5-8.0. The optimum temperature was observed at 20℃ and the thermal inactivation of lipase was obvious at 60℃. The lipase activity was inhibited by K＋, stimulated by Ca^2＋, and thermostability decreased in the presence of Ca^2＋, therefore the lipase was Ca^2＋ -dependent cold-adapted enzyme.     

福赛斯坦纳菌体外培养实验技术的研究

目的 探索福赛斯坦纳菌生长繁殖的基本条件,比较N-乙酰胞壁酸及不同营养因子对其生长繁殖的影响,筛选该菌体外培养的最佳营养条件,建立其体外培养的技术方法。方法 （1）培养基制备：在血平板中加0.005% N-乙酰胞壁酸形成改良培养基;制备血平板与不同浓度（0.5、3、10、50、100 mg/L）的N-乙酰胞壁酸形成的培养基;制备10 mg/L N-乙酰胞壁酸与氯化血红素、酵母提取物、维生素K₃、脱纤维羊血组合形成不同组别的培养基。（2）接种培养后,用磷酸盐缓冲液将细菌洗脱,并用酶标仪（OD₆₀₀）测定其吸光度。结果 福赛斯坦纳菌在含N-乙酰胞壁酸的培养基中生长更好,浓度为10 mg/L时促进作用最明显且细菌形态更为典型。在组3培养基中生长最快。结论 N-乙酰胞壁酸能促进福赛斯坦纳菌的生长繁殖,浓度为10 mg/L时促进作用最明显;N-乙酰胞壁酸及氯化血红素、维生素K₃、酵母提取物和脱纤维羊血组合能使其生长周期明显缩短。     

Potentially lethal radiation damage: repair by mammalian cells in culture

Less than optimum conditions with regard to cell division after x-irradiation provide the necessary environment in which mammalian cells can repair potentially lethal radiation damage. The kinetics of repair suggest that, during the repair process, a transient, unstable cellular state occurs which prevents cell division in complete growth medium. The capacity for repair appears to be dependent on cell age.     

影响大白菜游离小孢子培养若干因素的研究

影响大白菜游离小孢子培养因素主要有遗传基因、环境条件、培养温度和培养基等因素,研究结果表明:遗传基因对小孢子培养起着决定性的作用;供体植株的营养水平对小孢子胚胎发生有一定的影响;气温稳定在12℃～28℃时,所取的花蕾小孢子胚胎发生正常;33℃±2℃高温预培养能促进胚状体诱导;80次/min低频振荡极大提高出胚数;培养基中13%蔗糖处理、ph值在5.5～6.3对胚状体诱导和发育有促进作用,加入谷氨酰胺,L-丝氨酸,谷胱甘肽对不同基因型胚状体诱导有明显的促进作用。     

Habitat selection in a clonal plant

Rhizomatous growth may permit the nonrandom placement of ramets into different environments, but whether clonal plants are able to use this means to exercise adaptive habitat choice is not known. Western ragweed (Ambrosia psilostachya) plants are shown to preferentially colonize nonsaline soil over saline soil patches, and clones with the strongest preference for nonsaline soil are those least able to grow when restricted to saline conditions. In clonal plant species, nonrandom associations of genotypes with specific environments may thus reflect habitat selection by plants as well as selective mortality imposed by different habitat patches.     

A binding protein for fatty acids in cytosol of intestinal mucosa, liver, myocardium, and other tissues

A protein of molecular weight approximately 12,000 which binds long-chain fatty acids and certain other lipids has been identified in cytosol of intestinal mucosa, liver, myocardium, adipose tissue, and kidney. Binding is noncovalent and is greater for unsaturated than for saturated and medium-chain fatty acids. This protein appears to be identical with the smaller of two previously described cytoplasmic anion-binding proteins. Binding of long-chain fatty acids by this protein is greater than that of other anions tested, including sulfobromophthalein, and does not depend on negative charge alone. The presence of this binding protein may explain previously observed differences in intestinal absorption among fatty acids, and the protein may participate in the utilization of long-chain fatty acids by many mammalian tissues.     

茶藨生柱锈重寄生木霉产毒条件的优化

运用产毒培养基筛选、锈孢子诱导和正交试验对茶藨生柱锈重寄生木霉SS003菌株(rrichoderma atroviride)的产毒营养条件进行优化.结果表明,SS003在5种产毒培养基中均能产毒和生长,但Richard培养基更适合产毒培养,PD培养基则更适合菌丝生长;茶藨生柱锈的锈孢子对产毒具有一定抑制作用;SS003...     

Neuroglia electrically coupled to neurons

Applied electric current is transmitted between mammalian glial cells grown in tissue culture. A similar electrical coupling exists between certain neurons as well as between neuroglia and neurons. Although this phenomenon may be a peculiarity of mammalian neural cells maintained in culture, it may, on the other hand, represent a phenomenon with greater neurophysiological significance, a process whereby neurons can become silent.     

不同培养条件对草菇菌丝生物量的影响

为给草菇液体菌种的工业化生产提供具体的参考配方,明确草菇液体菌种生产过程中各种环境条件要求,在液体培养条件下,研究了不同培养基配方、培养温度、摇瓶装液量、接种量、pH及培养时间对草菇V37菌丝体生物量的影响。结果表明,草菇液体菌种适宜的培养条件是:液体培养基为配方B,摇瓶装液量80mL,接种量为10%,pH6~9,培养温度在30~32℃之间,培养时间是6~8天。     

Nicotinic antagonists enhance process outgrowth by rat retinal ganglion cells in culture

Functional nicotinic cholinergic receptors are found on mammalian retinal ganglion cell neurons in culture. The neurotransmitter acetylcholine (ACh) can be detected in the medium of many of these retinal cultures, after release presumably from the choline acetyltransferase-positive amacrine cells. The postsynaptic effect of endogenous or applied ACh on the ganglion cells can be blocked with specific nicotinic antagonists. Here it is shown that within 24 hours of producing such a pharmacologic blockade, the retinal ganglion cells begin to sprout or regenerate neuronal processes. Thus, the growth-enhancing effect of nicotinic antagonists may be due to the removal of inhibition to growth by tonic levels of ACh present in the culture medium. Since there is a spontaneous leak of ACh in the intact retina, the effects of nicotinic cholinergic drugs on process outgrowth in culture may reflect a normal control mechanism for growth or regeneration of retinal ganglion cell processes that is exerted by ACh in vivo.     

粉纹夜蛾(Trichoplusia ni)卵巢细胞系克隆株Tn5B_(1-4)特性的研究

通过有限稀释法由粉纹夜蛾(Trichoplusia ni)Tn 5 B_1细胞系中分离出多个细胞株,经筛选获得一个理想的克隆株Tn 5 B_(1-4),该克隆株的特性不同于原细胞系Tn_5B_1。该克隆株的细胞形态一致,细胞群体倍增时间较原细胞株短.而且细胞活力强,特别是在维持粉纹夜蛾单粒包埋核型多角体病毒(Tn SNPV)的复制能力方面高于原细胞系。另外经生物测定看出,在该克隆株中增殖的病毒毒力与虫体内增殖的病毒无显著差异。     

土壤水分对薇甘菊不同繁殖体单位存活能力和 植株表型可塑性影响

【目的】研究土壤水分对入侵性植物薇甘菊（Mikania micrantha H. B. Kunth）的克隆繁殖和植株形态特征的可塑性,提高对该物种的预警能力和控制能力。【方法】在人工气候箱内通过模拟干旱和淹水条件,研究土壤水分对薇甘菊不同繁殖单位存活能力的影响;通过温室水分控制试验研究低、中、高土壤水分和水深1 cm条件下,薇甘菊植株的表型可塑性。【结果】除节间和不定根外,土壤水分对薇甘菊其它营养繁殖体单位的存活率具有显著影响,且不同营养繁殖体单位在同等土壤水分条件下的存活率存在差异。当土壤含水量为12.5%时,薇甘菊地下营养繁殖体不定根+节点、不定根+根状茎+节点的存活率显著大于其它营养繁殖单位,而叶片则不能存活;随着土壤含水量的增加,各营养繁殖单位的存活率逐渐增大;当处于淹水状态时,在水深1 cm条件下,营养繁殖体节间、节点、不定根、不定根+节点不能存活,而其它营养繁殖体的存活率均超过80%;但水深为6 cm时,各营养繁殖体均不能存活。薇甘菊的主茎长、总分枝长、叶面积和主茎节间长均随着土壤含水量的增加而增大;分枝数则在高土壤水分含量下达到最大,且各土壤水分处理间差异显著;茎节数在中土壤水分含量下达到最大,后随着土壤含水量的增加而减小。薇甘菊的地上生物量、茎生物量、叶生物量以及地上生物量分配和叶生物量分配均随着土壤水分的增加而增大;而茎生物量分配在中等土壤水分含量下最大;地下生物量在高土壤含水量时达到最大,后在淹水状态下减小,而地下生物量分配则随着土壤含水量增加而减小。【结论】薇甘菊的克隆繁殖和植株形态随土壤水分变化具有很强的可塑性,在干旱（土壤含水量为12.5%）和淹水（水深1 cm）条件下,均可通过营养繁殖体克隆繁殖并生长,而在水深6 cm则不能存活。     

OBSERVATIONS ON THE BIOLOGICAL VALUE OF A MIXTURE OF ESSENTIAL AMINO ACIDS

(1) A mixture of "essential" amino acids, fed to rats, was found to be inferior from a nutritional point of view to enzymatic or acid casein hydrolysates or casein fed at comparable levels. (2) Evidence is presented which suggests that the nutritive inadequacy of the essential amino-acid diet may be due in part to toxic effects of unnatural forms of certain amino acids that can not be utilized.     

不同培养条件对草菇菌丝体生物量的影响

为给草菇液体菌种的工业化生产提供具体的参考配方,明确草菇液体菌种生产过程中各种环境条件要求,在液体培养条件下,研究了不同培养基配方、培养温度、摇瓶装液量、接种量、pH及培养时间对草菇V37菌丝体生物量的影响。结果表明,草菇液体培养基适宜的配方是配方B,适宜的摇瓶装液量在80 mL,适宜的接种量在10%,适宜的pH 6~9,适宜的培养温度在30~32℃之间,适宜的培养时间是6~8天。     

不同营养因子对土壤细菌可培养物种多样性的影响

通过在改良的VL55培养基中添加6种不同的营养因子,利用大量稀释法对采自河北、青海和云南的3份土壤样品进行细菌分离,并对所分离菌株进行16S r RNA基因序列系统发育分析,比较利用不同营养因子分离的可培养细菌物种多样性。结果表明,添加营养因子分离得到的细菌物种多样性明显高于对照;土样1对照分离得到5个属,添加6种营养因子的处理共分离得到22个属;土样2对照分离得到2个属,添加6种营养因子的处理共分离得到17个属;土样3对照分离得到6个属,添加6种营养因子的处理分离得到15个属。添加不同营养因子的培养基组合分离得到各自独特的细菌类群。其中,从青海土样中分离得到的菌株HBUM200206与运动东菌(Dongia mobilis)LM22T的亲缘关系最近,序列相似性为94.58%,可能是红螺菌科(Rhodospirillaceae)的一个潜在新属。此外,有12株菌与亲缘关系最近的模式菌株的16S r RNA基因序列相似性均小于98.65%,可能为潜在的新种。