膜蒸馏浓缩青霉素水溶液的实验研究

采用直接接触式膜蒸馏方法研究了热敏性物质青霉素水溶液浓缩过程的可行性及操作条件对浓缩过程的影响.实验结果表明,随热侧料液浓度的升高,膜渗透通量几乎不下降;随冷热侧温差的增加,膜渗透通量急剧增大;而且青霉素水溶液的流动性能是浓缩过程的重要影响因素.     

微量量热法研究细菌对大青叶生物碱和青霉素钠的耐药性

用瑞典产的2277型热活性检测仪测定了不同浓度的大青叶生物碱和青霉素钠对大肠杆菌的代谢作用,并用计算机处理得出最小抑菌浓度(MIC);在小于最小抑菌浓度的药物浓度下培养耐药菌,然后测出在该浓度作用下的耐药菌的生长代谢过程,并处理得出细菌对大青叶生物碱和青霉素钠耐药性的规律,利用该仪器还测定了交叉耐药性.     

Fenton试剂-石灰法处理青霉素废水

介绍了Fenton试剂－石灰法处理青霉素废水的初步实验，结果表明在适宜条件下对不同浓度的废水进行处理，CODCr去除率可达66.2%-70.7%。该方法工艺流程简单，反应条件温和，作为预处理工艺有一定的应用开发前景。     

The 2.4-A crystal structure of the penicillin-resistant penicillin-binding protein PBP5fm from Enterococcus faecium in complex with benzylpenicillin

Penicillin-binding proteins (PBPs) are membrane proteins involved in the final stages of peptidoglycan synthesis and represent the targets of beta-lactam antibiotics. Enterococci are naturally resistant to these antibiotics because they produce a PBP, named PBP5fm in Enterococcus faecium, with low-level affinity for beta-lactams. We report here the crystal structure of the acyl-enzyme complex of PBP5fm with benzylpenicillin at a resolution of 2.4 A. A characteristic of the active site, which distinguishes PBP5fm from other PBPs of known structure, is the topology of the loop 451-465 defining the left edge of the cavity. The residue Arg464, involved in a salt bridge with the residue Asp481, confers a greater rigidity to the PBP5fm active site. In addition, the presence of the Val465 residue, which points into the active site, reducing its accessibility, could account for the low affinity of PBP5fm for beta-lactam. This loop is common to PBPs of low affinity, such as PBP2a from Staphylococcus aureus and PBP3 from Bacillus subtilis. Moreover, the insertion of a serine after residue 466 in the most resistant strains underlines even more the determining role of this loop in the recognition of the substrates.     

苯胺法制备D-青霉胺

对D－青霉胺的合成进行了研究。将青霉素G钾盐溶解于水中，再依次加入甲苯和冰醋酸，室温下搅拌片刻后，加入苯胺，在氮气保护下，加热回流5h，一步反应生成了D－青霉胺，所得的产品结构由核磁共振谱和比旋光度确认，D－青霉胺的产率为64％。