Studies on the disposable obstetrical dressings sterilized by radiation and the effect of its application

In order to attain an optimum sterilization treatment to obstetric dressings, a new product made by us, with ⁶⁰Coγ-ray, the effects of radiation on standard bacteria pseudomonas aeruginosa ATcc27853, Escherichia coli ATcc25922, Staphylococcus aureus ATcc25923, Clostridium PB6KA, short Bacillus E60163202 and HBSAg were studied. Results showed that at the absorbed dose of 10 kGy, all the bacteria, bacillus and HBSAg were killed off, and sterilized with the dose, the dressings can completely accord with the demands of hygiene, which was further confirmed by microbiological and poisonous tests and the effects of clinical application. In Nov. 1988, the dressings was awarded the excellent prize in the 1st international exhibition of patent, new technique and new equipment in Guangzhou; its effective application is also reported in the paper.     

Radial Basis Function Networks Applied in Bacterial Classification Based on MALDI-TOF-MS

IntroductionWith the improvement of living standard,people pay more and more attention to health.Theaccurate and sensitive identification ofmicroorganisms plays an important role indiagnosing disease,identifying public healthhazards from pathogens,monitoring potential foodcontamination,regulating bioprocessingoperations,and detecting or identifying the natureof biological agents[1,2 ] . There are two major goalsfor the identification of microorganisms. Onewould be to develop a method to use in…     

壳多糖抑制细菌生长的构效关系

运用化学结构已清楚, 分属4大系列的29种壳多糖, 以4种不同类型的细菌(革兰氏阳性菌Ecoli K1、革兰氏阴性菌Bacillus cereus、Bacillus megaterium和Staphlylococcu aureus)为研究对象, 进行了壳多糖抑菌能力构效关系的研究. 在实验中采用96孔平板, 用计算机\|吸光值读数仪直接测定每个孔的吸光值, 获得了各个细菌在不同壳多糖浓度中的生长曲线和壳多糖抑制细菌生长的最低抑制浓度(MIC, Minimum inhibit concentration). 通过比较同一(各个)系列的壳多糖在这些相同(不同)细菌的MIC变化规律与壳多糖的化学结构的关系, 发现同一壳多糖对不同的细菌的MIC值是不相同的, 因而壳多糖抑制细菌生长的能力首先与细菌本身特点有关, 但与是否为革兰氏阳性菌或阴性菌无直接的相关性; 同一细菌对不同化学结构的壳多糖有一定的相关性, 在壳多糖的聚合程度(DP)相同的条件下, 壳多糖中氨基被乙酰化(DA)的程度越低, 壳多糖抑制细菌生长的MIC值越低, 壳多糖抑制细菌生长的能力就越强; 同样,在DA相同的情况下, 分子越小, 壳多糖抑制细菌生长的MIC值越低, 抑制细菌生长的能力越强. 根据上述实验结果, 初步推测壳多糖抑制细菌生长的机制可能与其在溶液中所带的正电荷多少有关.     

Energy transfer kinetics in the green bacterium Chloroflexus aurantiacus

The energy transfer from the main light harvesting complex of green bacteria into the reaction center has been examined by us. The chlorosomes, which are the highly organized antenna system of green bacteria, can perform an extremely efficient capture of light energy which is converted in the reaction center and results in essential electron transfer products. We have carried out some investigations of the energy transfer kinetics inChloroflexus aurantiacus in a two-wavelength fashion. The experiments seem to confirm previously obtained results.     

Development of a sandwiched microarray platform for studying the interactions of antibiotics with Staphylococcus aureus

It still confronts an outstanding challenge to screen efficient antibacterial drugs from millions of potential antibiotic candidates. In this regard, a sandwiched microarray platform has been developed to culture live bacteria and carry out high-throughput screening antibacterial drugs. The optimized lectin-hydrogel microarray can be used as an efficient bacterial capturing and culturing platform, which is beneficial to identify spots and collect data. At the same time, a matching drug-laden polyacrylamide microarray with Luria–Bertani (LB) culture medium can be generated automatically and accurately by using a standard non-contacting procedure. A large number of microscale culture chambers (more than 100 individual samples) between two microarrays can be formed by linking two aligned hydrogel spots using LB culture medium, where live bacteria can be co-cultured with drug candidates. Using Staphylococcus aureus (S. aureus) and four well-known antibiotics (amoxicillin, vancomycin, streptomycin and chloramphenicol) as model system, the MIC (minimum inhibitory concentration) values of the antibiotics can be determined by the drug induced change of bacterial growth, and the results demonstrate that the MIC values of amoxicillin, vancomycin and streptomycin are 1.7 μg mL⁻¹, 3.3 μg mL⁻¹ and 10.3 μg mL⁻¹, respectively.     

碱性品红修饰磁性纳米粒子的制备及在分枝杆菌分离中的应用

痰或其它各种体液内结核分枝杆菌(MTB)阳性是诊断结核病(TB)的金标准.结核硬脂酸(TBSA)是鉴定分枝杆菌与其它非分枝杆菌的特征组分,可用于TB的诊断[1,2]。     

生物降解芳香硝基化合物研究进展

大量人工合成的芳香硝基化合物广泛应用于燃料、染料、精细化工中间体、农药和军事等领域,由于其水溶性差、毒性大而对环境造成了严重污染。自然界中许多微生物具有降解这些化合物的功能。本文总结了近年来有关微生物降解芳香硝基化合物的进展情况及其在环境治理中的应用。     

Synthesis and Quantum Chemical Calculation of Benzamide Derivatives Containing Capsaicin and Their Bacteriostatic and Antifouling Properties

Thirteen benzamide derivatives containing capsaicin (BDCCs) have been successfully synthesized via the current method (Friedel‐Crafts alkylation reaction). The resultant monomers were characterized by IR, ¹H and ¹³C NMR, elemental analysis and HRMS. Characterization results were in agreement with the proposed structures of the products. Quantum chemistry calculation yielded three parameters, namely, Δε_L‐H, HF values (total energy) and dipole that could explain activity, stability and polarity respectively, and the relationship of each parameter with antimicrobial and antifouling performance was also preliminary discussed. The bacteriostatic property of the 13 compounds was evaluated by minimum inhibitory concentration (MIC) and bacteriostatic ring tests. Experimental results indicated that these compounds can inhibit Staphylococcus aureus and Escherichia coli. The antifouling effectiveness of the novel antifoulants was investigated using panel tests at the eighth harbor, Qingdao. Four‐month exposure results were compared. The compounds exhibited better antifouling properties than the blank panel without antifouling coating or the panel with a common coating. However, test panels with the antifouling coatings were covered with trace amounts of algae and Balanus because of weakening of antifouling ability over extended periods of time. All results demonstrate that the new compounds synthesized via our method can be applied in environment‐friendly antifouling paints.     

活性污泥中抗性细菌筛选及拉曼光谱检测

抗生素制药废水是污水处理中比较难处理的废水。抗生素与微生物作用的机理研究对于解决抗生素废水处理问题具有重要意义。拉曼光谱作为一种对样品无损,非侵入型,并且对水不敏感的检测手段,已越来越多地用于生物、医学的研究。从普通污水处理反应器的活性污泥里通过涂布法和平板划线法分离得到了4株对头孢他啶具有抗性的菌株,研究了其对头孢他啶的降解效果,降解率最高达45.44%。采用16S rRNA基因测序进行菌种鉴定,得到这些菌种分别属于气单胞菌属,芽孢杆菌属和红球菌属。对筛选出的细菌进行不同条件下拉曼光谱测定,探讨了细菌拉曼光谱的测试条件,结果显示CaF₂是测定生物样品拉曼光谱时效果最好的基底。通过拉曼光谱技术和主成分分析法对菌种进行了差异分析,提取了三个主成分,累积荷载达到83.9%。其中,第一主成分主要包括 748,1 003和1 126 cm-1等比较明显的峰位,第二主成分包括1 661和1 448 cm-1,第三主成分只有855 cm-1。本研究利用拉曼光谱对活性污泥筛选的抗性菌株进行生物大分子的差异表征,通过拉曼光谱对抗性菌种进行了较好的区分,与基因测序的结果相吻合,证明了拉曼光谱用于抗生素废水生物处理作用机理研究的可行性及优越性。     

Forward selection radial basis function networks applied to bacterial classification based on MALDI-TOF-MS

Forward selection improved radial basis function (RBF) network was applied to bacterial classification based on the data obtained by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). The classification of each bacterium cultured at different time was discussed and the effect of parameters of the RBF network was investigated. The new method involves forward selection to prevent overfitting and generalized cross-validation (GCV) was used as model selection criterion (MSC). The original data was compressed by using wavelet transformation to speed up the network training and reduce the number of variables of the original MS data. The data was normalized prior training and testing a network to define the area the neural network to be trained in, accelerate the training rate, and reduce the range the parameters to be selected in. The one-out-of-n method was used to split the data set of p samples into a training set of size p−1 and a test set of size 1. With the improved method, the classification correctness for the five bacteria discussed in the present paper are 87.5, 69.2, 80, 92.3, and 92.8%, respectively.