Trichosporon inkin peritonitis during continuous ambulatory peritoneal dialysis with bibliography review

We report a further case of peritonitis due to Trichosporon inkin in a patient undergoing continuous ambulatory peritoneal dialysis. Peritonitis caused by Trichosporon species is reviewed. This revised version was published online in June 2006 with corrections to the Cover Date.     

微生物酶不对称水解合成S（＋）—布洛芬的研究：Ⅱ.反应条件和产物提取

皮状丝孢酵母具有较强不对称水解底物专一性。在试验的五种布洛芬消旋酯中,水解甲酯和异丙酯生成Ｓ（＋）－布洛芬ｅｅ可达９７％,乙酯为９３％以上;而水解活性以乙酯最强。转化率高于３０５。不对称水解最适ｐＨ６．５－７．０;温度在２８－３７℃范围内拆分能力无明显差别。该酵母的水解酶为胞内酶,将酵母细胞制成丙酮干粉进行水解可提高立体专一性。产物Ｓ（＋）－布洛芬可借助于酸碱反应和有机溶剂提取得到,同时回收未水解     

脂肪酶高产菌株选育和菌种库的建立

从山东省济南市植物油厂、肉联厂、乳品厂、菜市场等处的含油土壤中分离筛选到80余株脂肪酶活性较高的产生菌,包括细菌、霉菌、酵母等各种类型,我们对其中的部分菌株进行了形态学及酶学性质的初步研究。一株酶活较高的菌株Y-11经鉴定为丝孢酵母属（Trichosporon）,用紫外线及亚硝酸对其进行了双重诱变、然后用制霉菌素及琥珀酸钠筛选耐药性突变株,使酶活提高155%,并将筛选到的菌株建立一个能够产生各具特色的脂肪酶的菌种库,为今后进一步开展脂肪酶应用研究打下基础。     

对产胞内脂肪酶的发酵性丝孢酵母超声波透性化处理的条件优化

发酵性丝孢酵母产胞内脂肪酶,为了把细胞整体作为脂肪酶催化剂,需对细胞进行透性化处理.利用超声波进行细胞透性化的适宜条件为:超声波输出功率180 W,每次辐射时间2s(间歇时间5 s),工作总时间1.2 min,菌体浓度40 g/L,此条件下细胞通透性可明显改善,透性化细胞脂肪酶表现出较高活力.     

Trichosporon porosum comb. nov., an anamorphic basidiomycetous yeast inhabiting soil,related to the loubieri/laibachii group of species that assimilate hemicelluloses and phenolic compounds

Several isolates representing the genus Trichosporon were collected over a 6-year period from soils in The Netherlands. Based on classical growth tests with carbon and nitrogen compounds these were identical. Three of these (CBS 8396, CBS 8397 and CBS 8522) were subjected to molecular analysis of the D1/D2 region of the large subunit of rDNA. This confirmed that the three strains were identical, yet distinct from other members of the genus. Conspecificity was demonstrated with the type strain (CBS 2040) of Apiotrichum porosum Stautz (1931), with the exception that A. porosum, which had been isolated from exudate of a yew tree, differed morphologically from the soil strains. Based on the identity of DNA base sequences, morphology was not considered to be an adequate parameter to separate otherwise identical strains into two genera. Therefore, the new combination Trichosporon porosum is presented. Based on molecular sequence analysis, T. porosum may be related to T. sporotrichoides, within a weakly related clade that includes species such as Trichosporon laibachii and Trichosporon loubieri. The strains of T. porosum degrade phenolic compounds and hemicelluloses, which are characteristics with potential ecological importance in soil habitats. Characters distinguishing the nine species of the laibachii/loubieri group of species were listed. These include traditionally used tests as well as assimilation patterns of some aliphatic and phenolic compounds. Based on these tests, species such as Trichosporon multisporum and T. laibachii could be separated.     

Physiological role of microbodies in the yeast Trichosporon cutaneum during growth on ethylamine as the source of energy,carbon and nitrogen

Compartmentation of the metabolism of ethylamine in Trichosporon cutaneum X4 was studied in cells, grown on this compound as the sole source of energy, carbon, and nitrogen. Transfer experiments indicated that an amine oxidase is involved in the early metabolism of ethylamine. The synthesis of this enzyme was induced by primary amines and was subject to partial carbon catabolite repression. Repression by ammonium ions was not observed. Adaptation of glucose-grown cells to growth on ethylamine was associated with the development of many microbodies, which developed from already existing organelles present in the inoculum cells and multiplied by division. Cytochemical experiments indicated that the organelles contained amine oxidase and catalase. Therefore, they were considered to play a key role in the metabolism of ethylamine. The physiological significance of the microbodies was investigated by fractionation studies of homogenized protoplasts from ethylamine-grown cells by differential- and sucrose-gradient centrifugation of subcellular organelles. Intact microbodies were only obtained when the isolation procedure was performed at pH 5.8 in the absence of Mg²⁺-ions. Analysis of the different fractions indicated that the key enzymes of the glyoxylate cycle, namely isocitrate lyase and malate synthase, cosedimented together with catalase and amine oxidase. In addition, activities of malate dehydrogenase, glutamate:oxaloacetate aminotransferase (GOT) and (NAD-dependent) glutamate dehydrogenase were detected in these fractions. Electron microscopy revealed that they mainly contained microbodies. Cytochemical experiments indicated that the above enzymes were all present in the same organelle. These findings suggest that microbodies of ethylamine-grown T. cutaneum X4 produce aspartate, so allowing NADH generated in the oxidation of malate by malate dehydrogenase to be quantitatively reoxidized inside the organelles in a series of reactions involving GOT and glutamate dehydrogenase. Aspartase and fumarase were not detected in the microbodies; activities of these two enzymes were present in the cytoplasm.Abbreviations ABTS 2,2-Azino-di(3-ethylbenzthiazoline sulfonate [6]) - DTT dithiothreitol - GOT glutamate:oxaloacetate aminotransferase - DTNB 5,5-dithiobis-2-nitrobenzoate - DAB diaminobenzidine - BSPT 2-(2-benzothiazolyl)-3-(4-phthalhydrazidyl)-t-styryl-sH-tetrazolium chloride - PF convex fracture face - EF concave fracture face     

The cytochrome P450-containing monooxygenase of Trichosporon cutaneum: Occurrence and properties

Trichosporon cutaneum metabolizes glucose purely oxidatively and cytochrome P450 was not detected in the reduced CO-difference spectrum of whole cells. However, in the isolated microsomal fraction the corresponding monooxygenase was present as shown by the appearence of cytochrome P450, NADPH-cytochrome c (P450) reductase and cytochrome b₅. The absorption maximum of the terminal oxidase in the reduced CO-difference spectrum shifted between 447 and 448 nm. Derepression of biosynthesis of all components was achieved by transition of the cells from carbon- to oxygen-limited growth in continuous culture. The monooxygenase exhibited aminopyrine demethylation activity but not -hydroxylation activity of lauric acid. With respect to the growth limiting nutrient (carbon and oxygen respectively), mitochondrial cytochrome content showed an analogous behavior as cytochrome P450 and cytochrome b₅.     

Optimization of chemoenzymatic Baeyer–Villiger oxidation of cyclohexanone to ε-caprolactone using response surface methodology

ε-Caprolactone (ε-CL) has attracted a great deal of attention and a high product concentration is of great significance for reducing production cost. The optimization of ε-CL synthesis through chemoenzymatic Baeyer–Villiger oxidation mediated by immobilized Trichosporon laibacchii lipase was studied using response surface methodology (RSM). The yield of ε-CL was 98.06% with about 1.2 M ε-CL concentration that has a substantial increase mainly due to both better stability of the cross-linked immobilized lipase used and the optimum reaction conditions in which the concentration of cyclohexanone was 1.22 M, the molar ratio of cyclohexanone:urea hydrogen peroxide (UHP) was 1:1.3, and the reaction temperature was 56.5°C. Based on our experimental results, it can be safely concluded that there are three reactions in this reaction system, not just two reactions, in which the third reaction is that the acetic acid formed reacts with UHP to form peracetic acid in situ catalyzed by the immobilized lipase. A quadratic polynomial model based on RSM experimental results was developed and the R² value of the equation is 0.9988, indicating that model can predict the experimental results with high precision. The experimental results also show that the molar ratio of cyclohexanone to UHP has very significant impact on the yield of ε-CL (p < .0006).     

关于皮状丝孢酵母（Trichosporon cutaneum）ST851破壁条件的研究

用脱壁酶（纤维素酶、半纤维素酶和蜗牛酶）作用于皮状丝孢酵母ＳＴ８５１制备原生质体。本文就酶的种类、酶液浓度、酶作用时间与温度、酶混合时间、混酶作用效果、酵母细胞的不同生长期诸因素对ＳＴ８５１原生质体形成的影响,进行了较为详尽的探讨。结果表明采用混酶作用（即先用纤维素酶和半纤维素酶预处理后再用蜗牛酶作用）是较理想的破壁条件,在ｐＨ５．８、３７℃条件下作用３．５－４ｈｒ,破壁率最高可达９５－９８％。