西罗莫司高产突变株FC904-33

西罗莫司是吸水链霉菌FC904产生的新型强效免疫抑制剂。为了获得高产西罗莫司突变株,采用UV、硝苯胍和甲基磺酸乙酯诱变剂诱变处理吸水链霉菌FC904的孢子悬液和发芽孢子,随后用西罗莫司对存活菌株进行自身代谢产物的耐受性试验,获得西罗莫司高产突变株FC904-33,其生物合成能力是原出发菌株的4.6倍。本文报道该突变株的培养特征、对抗生素的敏感性、西罗莫司生产能力和副产物等。     

新型强效免疫抑制剂西罗莫司F904的研究

从福建省福州市的土壤中分离到的链霉菌 FC90 4 ,经分类鉴定、菌株培养确定为吸水链霉菌。其发酵代谢产物 F90 4具有抗真菌、抗增殖和比环孢素强的免疫抑制活性。分离、纯化、结晶 ,得 F90 4 ,经理化性质、光谱分析和 X-射线单晶衍射研究证明 F90 4为三烯大环内酯新型强效免疫抑制剂西罗莫司。     

Clethramycin, a new inhibitor of pollen tube growth with antifungal activity from Streptomyces hygroscopicus TP-A0623. I. Screening, taxonomy, fermentation, isolation and biological properties

The cytoskeletal proteins, actin and myosin, play a central role in pollen tube growth. The pollen tube growth is inhibited by cytochalasin, which interferes with actin polymerization. In the screening of pollen tube growth inhibitors, clethramycin was found from the fermentation broth of an actinomycete strain TP-A0623. The producing strain was isolated from a root of Clethra barbinervis collected in Toyama, Japan and identified as Streptomyces hygroscopicus based on the taxonomic study. Clethramycin showed in vitro antifungal activity against yeast such as Candida albicans and C. glabrata with the MIC of 0.5 approximately 8 microg/ml, but weak activity against Gram-positive and negative bacteria (MIC > or = 64 microg/ml). Cytotoxicity of clethramycin was moderate and the IC50 was 57 microg/ml against HeLa cells and 120 microg/ml against WI-38 cells.     

西罗莫司同分异构体Rap-D1的分离与鉴定

从西罗莫司产生菌的突变株FC904-25的发酵产物中分离获得化合物Rap-D1的晶体。对其理化性质包括UV、IR、LC-MS、NMR谱等进行分析，结果表明Rap-D-与西罗莫司为同分异构体，具有相同的平面结构。通过单晶X-衍射确定了构型，它与文献报道经化学半合成获得的28-epirapamyein同质。     

Strain improvement studies on production of cephalosporin C from Acremonium chrysogenum ATCC 48272

Strain development for antibiotic production has been an essential prerequistie for efficient production process. Studies were carried out to produce high antibiotic yield strain by using UV and N-methyl-N1-nitro-nitrosoguanidine (NTG) as mutagens. A superior mutant (PNTG-22) with a productivity of 2.4 time (810-1995 microg/ml higher than, the parent strain was produced.     

Pathogenecity of fosfomycin-resistant strains isolated from Escherichia coli

Two fosfomycin-resistant strains, FRC14 (parent strain, Escherichia coli [E.coli] c73-18) and FRK104 (parent strain, E. coli O124), were isolated from spleens before the bacterial disappearance, after inoculating the parent strains intraperitoneally into mice and treating them with a single oral dose of fosfomycin. The resistant strains were successfully isolated by a replica method from a mass of sensitive cells of respective parent. To elucidate the pathogenesis of the resistant strains, their characteristics were investigated. The MIC of fosfomycin for FRC14 was 25 micrograms/ml (4 times the MIC for the parent) and that for FRK104 was 100 micrograms/ml (8 times the MIC for the parent). The strain FRC14 showed a defective utilization of sn-glycerol 3-phosphate (G3P), but utilization of other carbohydrates was similar to that of the parent strain. Thus, the strain FRC14 seemed to be a glpT mutant. The strain FRK104 did not use variety of carbohydrates including G3P, but used glucose 6-phosphate. The utilization of G3P was recovered in the presence of cAMP. Thus, the strain FRK104 seemed to be a ptsI mutant. These resistant strains were diminished their killing activity for mice in comparison to that of the each parent strain when they were inoculated intraperitoneally. The cell number of FRC14 decreased or disappeared in blood and spleen in mice, while that of the parent increased. The strain FRK104 diminished its ability of producing keratoconjuctivitis in guinea pigs in comparison to that of the parent strain.     

吸水链霉菌FC-904发酵代谢产物29-O-去甲基雷帕霉素的分离和结构鉴定

目的 从西罗莫司产生菌吸水链霉菌FC904的发酵液中分离纯化代谢产物FIM-R85，鉴定其化学结构。方法 采用硅胶柱层析和制备液相分离纯化获得FIM-R85，进行理化性质以及NMR、UV、IR和HRMS等波谱分析，鉴定其化学结构。 结果 纯化获得HPLC纯度为98.7%的FIM-R85，其为西罗莫司类似物，与29-O-去甲基雷帕霉素同质。结论 29-O-去甲基雷帕霉素为西罗莫司产生菌吸水链霉菌FC904的发酵代谢产物之一。     

Rifalazil retains activity against rifampin-resistant mutants of Chlamydia pneumoniae

Rifampin-resistant mutants of the obligate intracellular pathogen Chlamydia pneumoniae were isolated and characterized, including strains that contained multiple mutations in the rpoB gene encoding the rifampin binding site. The highest MIC of rifampin against a mutant strain exceeded 100 microg/ml, whereas the highest MIC of rifalazil was 0.125 microg/ml. Derivatives of rifalazil (new chemical entities; NCEs) showed from 2 approximately 4 fold lower MICs, as well as 2 approximately 8 fold lower bactericidal concentrations against both wild type and mutant strains when compared with rifalazil. These results suggest that rifalazil and NCEs are appropriate therapeutic agents for the treatment of C. pneumoniae infections from the point of view of potency and resistance development.     

新型强效免疫抑制剂F904的结构测定

分析吸水链霉菌 (Streptomyces hygroscopicus) FC90 4产生的具有免疫抑制活性的化合物 F90 4的理化性质及光谱学性质 (UV、IR、NMR、X- Ray衍射 ) ,证实化合物 F90 4的分子结构及空间构型与西罗莫司(sirolimus,又称 rapamycin)同质。     

氨基酰化酶高产菌株的选育与发酵

本实验以赭曲霉F_(449)为出发菌株,发酵产生氨基酰化酶,其野生型菌株产酶单位为12.2μ/ml发酵液。我们首先以紫外线诱变处理2min,得到其变异株F_9,产酶16μ/ml发酵液,然后对F_9菌株的原生质体进行亚硝基胍诱变处理15min,得F_(28)菌株,产酶24.7μ/ml发酵液,将F_(28)菌株在优化培养基中发酵培养,其产酰化酶单位提高到32.4μ/ml发酵液,与此同时,提取得到粗品酰化酶,其酶活为15,000μ/g。     

红霉素链霉菌遗传控制的研究 一 红霉素链霉菌无活性突变株回复突变株的筛选

利用亚硝基胍(NTG)对红霉素链霉菌(S.erythreus UV 80)活性菌株进行回复突变,获得了红霉素高产量变株。先以NTG(100μg/ml,1小时)处理母株,得无活性变株,再经诱变,得到回复突变株,其活性提高8％。进一步用NTG(1000μg/ml,1小时)诱变处理,得到了比原菌株红霉素产量高25％的变株。诱变剂的最适剂量为产生90～94％死亡率的剂量。同时还观察到红霉素链霉菌变株的培养特征和生产能力之间有相关性。     

3L自动发酵罐中西罗莫司的发酵研究

采用美国NBS公司生产的BIOFLO3000型3L发酵罐进行西罗莫司发酵代谢过程的考察和代谢参数的累积,建立了较为适应的西罗莫司发酵条件,罐上发酵水平与摇瓶发酵水平相当.     

MIC test of Campylobacter jejuni/coli

Using 3 kinds of medium, Mueller-Hinton (M-H) agar, M-H agar added with defibrinated horse blood and lysed horse blood, susceptibilities of Campylobacter were tested quantitatively to 12 antibacterial agents. The result showed no remarkable difference between them. MIC was examined with the cell concentration of McFarland unit 0.5 and 100-times dilution, and there was no significant difference between them except for 2 strains, on which erythromycin showed MIC of 6.25 micrograms/ml at McFarland unit 0.5 and 0.39 micrograms/ml at 100-times dilution. Eighty-two clinical isolates of C. jejuni and 6 of C. coli were tested for their susceptibility to 12 antibacterial agents. These strains were most susceptible to gentamicin and amikacin and less susceptible to benzylpenicillin, carbenicillin and cephaloridine with the MIC of 25 micrograms/ml. There were 2 peaks of susceptibility distribution to minocycline (0.2 and 50 micrograms/ml). In tests for beta-lactamase of C. jejuni and C. coli, 3 strains obtained from 1 patient were positive.     

白色念珠菌酮康唑抗药株的筛选

目的获得白色念珠菌的酮康唑抗药株。方法采用美国国家临床实验标准化委员会 (NC CLS)推荐的最小抑菌浓度 (MIC)测定法 ,从 8株不同来源的白色念珠菌中筛选出YS2 0 1 (MIC为0 0 62 μg/mL)作为出发菌株 ,分别利用紫外线 (UV)和亚硝基胍 (NTG)对其原生质体进行诱变。结果经大量筛选 ,得到抗药突变株UP1 1及NP2 9,其MIC分别达到 3 5 μg/mL和 75 μg/mL。结论获得酮康唑抗药株 ,突变株的抗药特性稳定。     

Determination of destruxins, cyclic peptide toxins, produced by different strains of Metarhizium anisopliae and their mutants induced by ethyl methane sulfonate and ultraviolet using HPLC method.

Metarhizium anisopliae produces a family of cyclic peptide toxins, destruxins (DTXs), which exhibit various insecticidal activity. Four major DTXs have been separated by HPLC and identified by the liquid chromatography electrospray mass spectrometry (LC-ESI-MS) methods. Strain F061 of M. anisopliae produced large amounts of (DTXs), especially DTX-A (12.84+/-0.04 microg/ml), DTX-B (66.89+/-2.57 microg/ml) and DMDB (1.41+/-0.13 microg/ml). High levels of DTX-E (4.19+/-0.13 microg/ml) were produced by strain F007 of M. anisopliae. The results of our studies also showed that either ethyl methane sulfonate (EMS) or ultraviolet (UV) can significantly increase the production of DTXs. Mutant 61E-9 produced high levels of DTX-A (30.05+/-1.97 microg/ml), DTX-B (110.37+/-10.02 microg/ml) and DMDB (8.30+/-0.45 microg/ml). High levels of DTX-E (20.59+/-2.65 microg/ml) were produced by mutant 7E-3. Both mutant strains are suitable for industrial fermentation processes and possess a wide range of potential applications in the area of metabolic toxin production.     

Mulundocandin, an echinocandin-like lipopeptide antifungal agent: biological activities in vitro.

Mulundocandin (MCN) is an antifungal lipopeptide which belongs to the echinocandin class of antimycotic agents. MCN exhibited good in vitro activity against Candida albicans and C. glabrata isolates with MIC ranges of 0.5-4.0 microg/ml and 2.0-4.0 microg/ml, respectively. MCN also exhibited some activity against C. tropicalis isolates (MIC range 1.0-8.0 microg/ml). However, MCN was poorly active against other non-albicans isolates and was inactive against Cryptococcus neoformans, Aspergillus species and Trichophyton. MCN appeared to exert its antifungal activity through preferential inhibition of germ tube formation (MIC-HY 0.015-0.03 microg/ml) and was typically less active on the yeast form (MIC 0.5-4.0 microg/ml). In kill-curve experiments 99.9% reductions in cell viability were observed following 8 hours exposure to MCN at 4 x MIC and 8 x MIC and after 5 hours exposure to 16 x MIC.     

'In vitro' development of metronidazole, erythromycin, amoxicillin and gentamicin resistance in Helicobacter pylori

Serial passage of 37 Helicobacter pylori clinical isolates on increasing concentrations of metronidazole rapidly produced five strains with MICs up to 512 fold higher than those for the original strains. For these five metronidazole-resistant strains the MICs of erythromycin, gentamicin and amoxicillin were unchanged. When they were submitted to the same technique for these last antimicrobial agents, only one strain developed high level resistance to erythromycin and gentamicin having MIC values respectively up to 32 and 64-fold increased. Finally, no amoxicillin-resistant Helicobacter pylori could be obtained.     

由DL-5-苯乙内酰脲酶法生产D-苯甘氨酸的菌种选育

本实验以假单孢菌Pseudomonas SP.27为出发菌株由DL-5-苯乙内酰脲发酵生产D-苯甘氨酸。野生菌产量为15.85μg/ml.首先对其进行紫外诱变处理1min,筛选出菌株Q_6,其产量为256.7μg/ml.然后用Q-6制备球形体,进行亚硝基胍诱变处理60min,得到Q_(68)菌株,其产量为453.4μg/ml.     

Stemphones, novel potentiators of imipenem activity against methicillin-resistant staphylococcus aureus, produced by Aspergillus sp. FKI-2136

A fungal strain FKI-2136 identified as genus Aspergillus was found to produce potentiators of imipenem activity against methicillin-resistant Staphylococcus aureus (MRSA). Two new compounds designated stemphones B and C were isolated along with a structurally related known compound cochlioquinone D from the fermentation broth of the producing strain by solvent extraction, silica gel column chromatography and preparative HPLC. These compounds have a common tetracyclic quinone skeleton. Stemphone C potentiated imipenem activity against the MRSA 512 fold by decreasing MIC value of imipenem from 16 microg/ml to 0.03 microg/ml.     

头孢哌酮钠/舒巴坦钠对铜绿假单胞菌的最低抑菌浓度和防突变浓度研究

目的:研究头孢哌酮钠/舒巴坦钠对铜绿假单胞菌的最低抑菌浓度(MIC)和防突变浓度(MPC),为控制细菌耐药提供参考。方法:采用肉汤法富集铜绿假单胞菌标准菌株及14株临床分离菌株,采用琼脂平板稀释法考察头孢哌酮钠/舒巴坦钠对铜绿假单胞菌的MIC、MPC值,计算MIC90、MPC90、选择指数(SI)。结果:头孢哌酮钠/舒巴坦钠对15株铜绿假单胞菌的MIC、MPC均为4³2μg/ml,MIC90、MPC90均为32μg/ml,SI为1。结论:头孢哌酮钠/舒巴坦钠在临床治疗浓度下不容易引起铜绿假单胞菌耐药突变菌株的富集。