嗜盐和嗜碱放线菌的分离及多相分类研究

本文综述了放线菌分类学研究的意义和进展，分析了放线菌分类学研究特点及发展趋势；同时综述了嗜盐、嗜碱放线菌的研究进展，分析了嗜盐和嗜碱放线菌研究的重要性和意义。通过对采自渤海沿岸盐场、青海盐湖、张北盐湖、曲周、保定等地盐碱和高盐的样品进行嗜盐和嗜碱放线菌的分离，建立了适于嗜盐和嗜碱放线菌的分离培养条件；找到了广适性的嗜盐放线菌培养用培养基；发现了嗜盐放线菌多数耐碱的规律。采用形态培养特征、生理生化测定、细胞化学组分分析、DNA G＋C mol％测定以及DNA同源性分析和165 rDNA序列为基础的系统发育分析等相结合的多相分类技术对分离得到的部分典型菌株系统地进行了分类研究，从表型、基因型和系统发育三个层次对其分类地位进行了确定。本研究发现嗜盐放线菌新属新种1个，为波状盐场放线菌新属新种（Actinoosalterria undulata gen.nov．sp．nov），嗜盐放线菌新种4个，分别是：沧州拟诺卡氏菌(Nocardiopsl's cangzhouensis sp．nov．）、塘沽拟诺卡氏菌(Nocardiopsis tangguensis sp.nov）、茶卡拟诺卡氏菌(NocardioPs沽chakaensis)和盐场链霉菌(Streptomyces salinarum sP.nov.）；发现嗜碱放线菌新种2个，分别是；布尔津拟诺卡氏菌（NocardioPsis buerjinensis sp.nov．）和城墙拟诺卡氏菌（Nocardiopsis rampartis sp.nov．）；另有2株嗜碱放线菌鉴定为达松维尔拟诺卡氏菌，2株嗜碱放线菌鉴定为产气味拟诺卡氏。论文研究中还初步建立了放线菌磷酸类脂高效液相色谱测定的方法与测定条件。

阿佛曼链霉菌的~(12)C离子辐照效应及高产菌株选育；Research on Mutation Breeding of High-producing Strains from Streptomyces Avermitilis Irradiated by Ion Beam of ~(12)C~(6+)

选用12C6+离子辐照诱变阿维菌素B1a产生菌ZJAV-A1,研究其诱变效应。实验结果表明,12C6+离子辐照剂量50Gy时致死率97%,正突变率最高可达到34.2%。通过12C6+离子诱变处理,结合平板培养基及斜面培养基的正突变菌株筛选,最终获得一株稳定性良好,阿维菌素B1a组分产量稳定在4460—4588μg/ml之间,较出发菌株提高11.1%—14.7%的突变株ZJAV-Y1-203。

Complex organization of the Streptomyces avermitilis genes encoding the avermectin polyketide synthase

The avermectin (Av) polyketide synthase (PKS) and erythromycin (Er) PKS are encoded by modular repeats of DNA, but the genetic organization of the modules encoding Av PKS is more complex than Er PKS. Sequencing of several related DNA fragments from Streptomyces avermitilis that are part of the Av biosynthetic gene cluster, revealed that they encode parts of large multifunctional PKS proteins. The Av PKS proteins show strong similarity to each other, as well as similarity to Er PKS proteins [Donadio et al., Science 252 (1991) 675–679] and fatty acid synthases. Partial DNA sequencing of the 65-kb region containing all the related sequence elements in the avr genes provides evidence for twelve modular repeats encoding FAS-like domains. The genes encoding the Av PKS are organized as two sets of six modular repeats which are convergently transcribed.

Methyleneimidazoline Complexes of Iridium, Rhodium, and Palladium from Selective C(sp(3))-H Bond Activation

Palladium, iridium, and rhodium complexes of 2-methyleneimidazolines have been synthesized by selective phosphine-assisted activation of the 2-methyl C-H bonds in 2-methylimidazolium compounds. Metallacycles of various sizes were obtained in the reaction of phosphine-tethered 2-methylimidazolium compounds and [{M(cod)X}(2)] (M = Rh or Ir cod = 1,5-cyclooctadiene: X = alkoxyl or Cl). representative complexes were characterized by X-ray crystallography. The selectivity for aliphatic C(sp(3))H versus aromatic C(sp(2))H activation could be adjusted by means of the steric bulk of the OR ligand, whereby a bulky, OR group favors activation of the 2-methyl C(sp(3))-H bond. Experimental results confirmed that a methyl C-H activation product (a seven-membered iridacycle) is the kinetic product, while the aryl C-H activation product (a six-membered iridacycle) is the thermodynamic product.

High resolution mass spectrometric alveolar proteomics: Identification of surfactant protein SP-A and SP-D modifications in proteinosis and cystic fibrosis patients

In the present study, one- and two-dimensional gel electrophoresis combined with high resolution Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS) have been applied as powerful approaches for the proteome analysis of surfactant proteins SP-A and SP-D, including identification of structurally modified and truncation forms, in bronchoalveolar lavage fluid from patients with cystic fibrosis, chronic bronchitis and pulmonary alveolar proteinosis. Highly sensitive micro preparation techniques were developed for matrix-assisted laser desorption/ionization (MALDI) FT-ICR MS analysis which provided the identification of surfactant proteins at very low levels. Owing to the high resolution, FT-ICR MS was found to provide substantial advantages for the structural identification of surfactant proteins from complex biological matrices with high mass determination accuracy. Several protein bands corresponding to SP-A and SP-D were identified by MALDI-FT-ICR MS after electrophoretic separation by one- and two-dimensional gel electrophoresis, and provided the identification of structural modifications (hydroxy-proline) and degradation products.

Cloning, characterization, and molecular application of a beta-agarase gene from Vibrio sp strain V134

V134, a marine isolate of the Vibrio genus, was found to produce a new beta-agarase of the GH16 family. The relevant agarase gene agaV was cloned from V134 and conditionally expressed in Escherichia coli. Enzyme activity analysis revealed that the optimum temperature and pH for the purified recombinant agarase were around 40 degrees C and 7.0. AgaV was demonstrated to be useful in two aspects: first, as an agarolytic enzyme, the purified recombinant AgaV could be employed in the recovery of DNA from agarose gels; second, as a secretion protein, AgaV was explored at the genetic level and used as a reporter in the construction of a secretion signal trap which proved to be a simple and efficient molecular tool for the selection of genes encoding secretion proteins from both gram-positive and gram-negative bacteria.

Cloning, characterization, and molecular application of a beta-agarase gene from Vibrio sp strain V134

V134, a marine isolate of the Vibrio genus, was found to produce a new beta-agarase of the GH16 family. The relevant agarase gene agaV was cloned from V134 and conditionally expressed in Escherichia coli. Enzyme activity analysis revealed that the optimum temperature and pH for the purified recombinant agarase were around 40 degrees C and 7.0. AgaV was demonstrated to be useful in two aspects: first, as an agarolytic enzyme, the purified recombinant AgaV could be employed in the recovery of DNA from agarose gels; second, as a secretion protein, AgaV was explored at the genetic level and used as a reporter in the construction of a secretion signal trap which proved to be a simple and efficient molecular tool for the selection of genes encoding secretion proteins from both gram-positive and gram-negative bacteria.