噬菌体在肠杆菌科细菌分类鉴定中的敏感试验研究

目的通过加入蓝四氮唑指示剂提高噬菌体在肠杆菌科细菌分类鉴定中的敏感性.方法加蓝四氮唑法.结果加入蓝四氮唑后提高了噬菌体在肠杆菌科鉴定中的敏感性和清晰度.结论建议在应用噬菌体鉴定肠杆科细菌时,加入蓝四氮唑指示剂.     

Structure and morphogenesis of bacteriophage T4

Bacteriophage T4 is one of the most complex viruses. More than 40 different proteins form the mature virion, which consists of a protein shell encapsidating a 172-kbp double-stranded genomic DNA, a tail, and fibers, attached to the distal end of the tail. The fibers and the tail carry the host cell recognition sensors and are required for attachment of the phage to the cell surface. The tail also serves as a channel for delivery of the phage DNA from the head into the host cell cytoplasm. The tail is attached to the unique portal vertex of the head through which the phage DNA is packaged during head assembly. Similar to other phages, and also herpes viruses, the unique vertex is occupied by a dodecameric portal protein, which is involved in DNA packaging.Received 18 February 2003; received after revision 16 April 2003; accepted 9 May 2003     

Preliminary observations of a bacteriophage infectingXenorhabdus luminescens (Enterobacteriaceae)

A bacteriophage infective toXenorhabdus luminescens, a bacterial symbiont of heterorhabditid nematodes, was recovered from insects that supported poor nematode development. Plaque tests showed the phage particles to be infective only to primary and not secondary colonies ofX. luminescens. The phage was not infective toX. nenatophilus primaries or secondaries. The bacteriophage particles ranged 80–90 nm in length, with the head ranging from 40 to 50 nm in diameter. Restriction analysis was performed on isolated bacteriophage DNA. This first report of a bacteriophage fromXenorhabdus species has pratical implications since it could be detrimental to cultures ofHeterorhabditis nematodes that are being produced throughout the world for the biological control of insects.     

L—山梨糖发酵中的芽孢杆菌噬菌体及抗噬菌体菌株的选育

从济南制药厂L—山梨糖混合发酵液中分离得到四株芽孢杆菌噬菌体,其中一株来自寄主巨大芽孢杆菌,三株来自腊状芽孢杆菌,这些噬菌体都是有尾的,根据形态可分为二类。通过选育获得了几株抗噬菌体菌株,经摇瓶混合发酵试验,表明抗株不但具有稳定的抗性而且保持了原种的性能。     

抗噬菌体谷氨酸生产菌的选育——细胞融合技术在细菌育种方面的应用

本文利用紫外线诱变的方法获得了抗噬菌体谷氨酸生产菌株.为提高抗噬菌体菌株的产量,作者对谷氨酸生产菌进行了属间融合试验,结果获得了产酸为5.8—6.0％的抗噬菌体谷氨酸生产菌.在适量青霉素存在下可获得99.9％的原生质体。选用最佳条件再生率达20％。在选择培养基上获得融合子,其融合率达1.15×10~(-(?))量级,其中具噬菌体抗性的菌株占22.2％.     

The potential role of endogenous bacteriophages in controlling invading pathogens

Bacteriophages (phages) are omnipresent in our environment, and recent studies highlight their potential impact on the microbial world. Phages can also be present in mammalian organisms, including man (intestines, oral cavity, urine, sputum and serum). Data are available which suggest that those endogenous phages could play an important role in eliminating bacteria and regulating the body ecosystem. Furthermore, our most recent findings suggest that phages can exert immunosuppressive action in the gut, helping control local inflammatory and autoimmune reactions, and demonstrate anticancer activity. We hypothesize that phages could act in concert with the immune system in immunosurveillance against bacteria, viruses and cancer.article dedicated to Professor Ludwik Hirszfeld to commemorate the 50^th anniversary of his deathReceived 8 September 2004; received after revision 18 October 2004; accepted 21 October 2004