Isolation of a motile mycoplasma from fish

For the first time a mycoplasma has been isolated from fish. The organism, designated strain 163K, was isolated on modified Hayflick medium under aerobic conditions at 25 degrees C from the gills of a tench (Tinca tinca L.). It showed the characteristic features of mycoplasmas. In addition it was flask-shaped with a distinct head-like structure and was able to attach to inert surfaces and living cells. The most interesting property of the organism was its ability to show fast gliding motion. Movement was only in the direction of the head-like structure and was not interrupted by resting periods.     

Isolation of mycoplasma membranes by dicyclohexylcarbodiimide-induced lysis.

A simple procedure was devised to prepared membranes from Mycoplasma gallisepticum cells. The cells were lysed in an isosmotic NaCl solution by dicyclohexylcarbodiimide, which blocks ATPase activity and interferes with the regulation of cell volume. The procedure can be used to isolate membranes of other osmotically resistant mycoplasmas.     

Isolation of acholeplasmas and a mycoplasma from vegetables.

The isolation of Mollicutes from food has not been reported. To isolate Mollicutes in the presence of high levels of unwanted bacteria, we first incubated fresh vegetables in liquid culture media containing lysozyme, ampicillin, and thallous acetate. Culture fluids were than separated from the vegetable samples, subjected to one freeze-thaw cycle, and passed through a filter of 0.4-micron porosity. Filtered samples were cultured in SP4 medium and in a conventional medium containing horse serum. With this procedure 21 acholeplasma isolations representing three species were obtained from endive, broccoli, and kale. Of 35 food samples tested, 11 were positive for acholeplasmas; acholeplasmas isolated from 6 of these samples were recovered only in SP4 medium. In seven single vegetable samples, two or more Acholeplasma spp. were isolated. A. laidlawii was isolated from all three vegetables and A. axanthum was found in broccoli and kale. Four isolates were serologically identified as A. oculi. Mycoplasma verecundum was the only Mycoplasma species recovered. Several isolates could not be typed serologically, as they reacted with antisera to both A. morum and A. hippikon. these isolates may include new Acholeplasma spp.     

延迟5分钟剖宫产造全脑缺氧缺血新生大鼠模型

目的建立围产期全脑缺氧缺血性损伤的新生大鼠模型。方法 SD雌性大鼠妊娠21 d时,颈椎脱臼法处死,用止血钳夹闭双侧子宫角血管5 min后,剖宫产取出新生大鼠,交由代乳鼠喂养。结果造模组雌性大鼠9只,共娩出新生大鼠91只,出生3 d内死亡7只,死亡率7.7%。新生大鼠出生第2天进行翻身实验,第14天进行悬吊实验和斜坡实验,造模组和其余各组均有显著性差异。新生大鼠出生后21 d,取脑组织切片行HE染色,显示大脑皮层典型的缺氧缺血性损伤,与正常组相比,可见神经细胞明显的病理形态学改变。结论采用延迟5min剖宫产和代乳鼠喂养的方法,操作简便,并结合行为学测试筛选行为异常者,可建立稳定可靠、可供长期实验使用的围产期全脑缺氧缺血性损伤的新生大鼠模型。     

Isolation and propagation of keratinocytes derived from Cashmere goat fetus

The study was conducted to isolate epidermal keratinocytes from Cashmere goat fetus with the aim to develop suitable conditions for keratinocyte cultivation and propagation. The methods developed for keratinocyte culture include (i) use of a feeder-layer of mitotically inactivated fibroblasts obtained from goat and mouse fetal skin, (ii) use of a substrate such as collagen IV, or (iii) without use of any substrate. Epidermal cell removal was established by enzymatically separating keratinocytes from 12 to 16 weeks aged fetal skin tissues treated with 0.125% trypsin solution overnight at 4 degrees C. The cells were maintained in all culture conditions with serum containing medium. Keratinocyte multiplication and proliferation were comparable in different culture conditions and the improved cellular attachment and growth have been obtained in cultures on feeder layers. Colony forming keratinocytes on feeder layer were heterogeneous in their growth potential. In feeder free conditions, high cellular density was required at plating for sub-cultivation as their poor attachment in culture dishes. This study reports the comparative efficacy of different culture conditions for keratinocyte isolation and in vitro propagation originating from Cashmere goat fetus.     

A procedure to produce gnotobiotic calves by cesarean section.

An effective and economical method was developed for procuring and rearing calves in gnotobiotic conditions. To evaluate apparatuses and surgical techniques, three calves, 1 to 3, welf 1 was weak and pale at delivery and died within 5 hours after delivery. Calf 2 was delivered alive, but died from a human error at 3 days of age. It was free from demonstrable bacteria and fungi at that time. Calf 3 was also successfully delivered and raised. It was killed at 10 days of age, since fungi were isolated from the feces and waste materials from it.     

观赏犬剖腹产手术的体会

由于观赏犬具有体格小、产道狭窄、双角子宫、胎儿较多等特点 ,难以进行矫正术和切胎术 ,采用药物催产和牵引术亦难奏效。因此 ,观赏犬剖腹产手术在临床上极为常见。剖腹产手术成功的标志有 3点 :第一是母仔平安 ,第二是伤口无感染 ,第三是今后交配能受孕和顺产。 1 991年至今 ,笔者做过 2 0 0 0多例犬、猫、海狸鼠剖腹产手术 ,从中悟出做好剖腹产手术的一些体会 ,现总结如下。1　剖腹时机要及时　犬生产时努责的次数、强弱、间隔时间的长短 ,母犬的表现 ,每只犬都不一样 ,即使同一母犬的不同胎次 ,或者同一胎中生产先后胎儿的表现也不一样 …     

人胎儿脊髓神经干细胞的分离培养

本文旨在探讨是否能够从低温保存的流产儿分离培养出脊髓神经干细胞。将14周流产儿在4℃下保存,2、6和12h后取脊髓,将颈段、胸段、腰骶段分别进行无血清培养,并用胎牛血清诱导分化。用克隆培养的方法验证培养细胞的干细胞特性;用免疫荧光细胞化学的方法检测神经干细胞标志nestin及干细胞诱导分化后神经元标志MAP2、星形胶质细胞标志GFAP、胆碱能标志ChAT,并比较不同时间点以及不同部位分离的神经T细胞的差异。在各个时间点,从颈段、胸段、腰骶段脊髓均分离培养出具有连续增殖能力的神经球,其中腰骶段分离出的神经球数量最多,12h组各段分离出的神经球较2、6h组显著减少。各段培养中的神经球均为nestin阳性,诱导分化后均能够产生GFAP阳性星形胶质细胞、MAP2阳性神经元以及ChAT阳性胆碱能神经元。各段培养中的神经干细胞的克隆形成能力相似。以上结果表明,从低温保存的人胎儿能够分离培养出脊髓神经干细胞,这为基础研究以及未来治疗应用提供了新的细胞来源。     

Isolation and restriction endonuclease analysis of a mycoplasma plasmid

A 1.7-kb plasmid was isolated from a large colony type strain of Mycoplasma mycoides subsp. mycoides. It was cloned into the Escherichia coli vector M13mp19, and DNA from the resultant recombinant was used to construct a restriction map of the plasmid. Because mycoplasmas show deviation from normal coding patterns, the availability of a mycoplasma plasmid could be useful in the development of a cloning vector for them.     

Isolation of copper thionein from rat liver

The inducible Cu-binding protein from adult rat liver previously referred to as Cu-chelatin has been purified and shown to be Cu-thionein. The Cu-protein was purified to homogeneity by gel filtration and thiopropyl-Sepharose chromatography. The Cu-thionein exhibited an amino acid composition similar but not identical to that of the two forms of rat liver Cd,Zn-thionein. The polypeptide-chain molecular weight of Cu-thionein was indistinguishable from that of Cd,Zn-thionein. The identification of the Cu-protein as metallothionein was substantiated by the complete immunological cross-reactivity with antisera prepared against purified rat liver Cd,Zn-thionein. Purified Cu-thionein bound 9–11 g atoms of Cu per mole of protein in an electron paramagnetic resonance nondetectable form. The $\text{Cu}\text{Zn}$ ratio of the protein is about 100. Ion-exchange chromatography resolved the Cu-protein into three polymorphic forms which differed from the polymorphism of Cd,Zn-thionein.