宇佐美曲霉木聚糖酶基因xynⅡ在不同毕赤酵母中的分泌表达

将宇佐美曲霉E001的内切-1,4-木聚糖酶基因克隆到毕赤酵母表达载体pPIC9K中,得到重组质粒pPXY-NII,将其经SalⅠ线性化后分别转化2株毕赤酵母GS115和KM71,xynⅡ基因通过同源重组被整合到毕赤酵母染色体上,并处于酵母α因子的下游,经筛选获得阳性重组菌PXGL98(Mut+)和PXKL29(Muts)。该木聚糖酶基因在2株毕赤酵母中均实现了分泌表达。同时对工程菌的发酵条件进行了优化,在甲醇诱导下,PXGL98与PXKL29培养物上清液中的酶活力分别可达1156.92 U/mL和1646.03 U/mL。     

Comparative analysis of glycogen and trehalose accumulation in methylotrophic and nonmethylotrophic yeasts

Trehalose and glycogen accumulate in certain yeast species when they are exposed to unfavorable growth conditions. Accumulations of these reserve carbohydrates in yeasts provide resistance to stress conditions. The results of this study indicate that certain Pichia species do not accumulate high levels of glycogen and trehalose under normal growth conditions. However, depending on the Pichia species, both saccharides accumulate at high levels when the Pichia cells are exposed to unfavorable or stress-inducing growth conditions. Growth on glycerol or methanol mostly led to trehalose accumulation in Pichia species tested in this study. It was shown that the metabolic pathways for glycogen and trehalose biosynthesis are present in Pichia species. However, it appears that the biosynthesis of trehalose and glycogen may be regulated in different manners in Pichia species than in the yeast S. cerevisiae.     

离心法分离毕赤酵母活细胞和死细胞

本文以毕赤酵母为研究对象,探索出一种分离活酵母细胞的新方法。研究发现,通过改变淋巴细胞分离液和50%聚蔗糖溶液的比例,获得不同密度的酵母细胞分离液,进而通过离心分层的方法可使毕赤酵母活细胞主要存留于离心液的上层。当酵母细胞分离液的密度为1.1467 g/mL (27.5%淋巴细胞分离液+72.5%聚蔗糖溶液),分离液上下层中酵母活细胞的分配比例差别达到最大,分别为94.67%(分离液上层)和5.33%(分离液下层)。毕赤酵母细胞浓度为4.35×108~1.13×109/mL时,活细胞在分离液上下两层的分配比例约为95%和5%。低毕赤酵母细胞存活率有利于离心分离。本方法可用于有效分离培养液中的毕赤酵母活细胞。     

来源于Escherichia coli的高比活植酸酶基因的高效表达

高效表达高比活植酸酶是进一步提高植酸酶发酵效价、降低植酸酶生产成本的一个有效途径。对源于Escherichiacoli的高比活植酸酶基因appA ,按照毕赤酵母 (Pichiapastoris)密码子的偏爱进行了密码子优化改造。该改造后的基因appA m按正确的阅读框架融合到毕赤酵母表达载体pPIC9上的α 因子信号肽编码序列 3′端 ,通过电击转化得到重组转化子。对重组毕赤酵母的Southernblotting分析证实植酸酶基因已整合到酵母基因组中 ,并确定了整合基因的拷贝数。Northernblotting分析证实植酸酶基因得到了正常转录。SDS PAGE分析和表达产物的研究表明 ,植酸酶得到了高效分泌表达 ,在 5L发酵罐中植酸酶蛋白表达量达到 2 5mg mL发酵液 ,酶活性 (发酵效价 )达到 7 5× 10 6 IU mL发酵液以上 ,大大高于目前报道的各种植酸酶基因工程菌株的发酵效价。     

Assembly of human prolyl 4-hydroxylase and type III collagen in the yeast pichia pastoris: formation of a stable enzyme tetramer requires coexpression with collagen and assembly of a stable collagen requires coexpression with prolyl 4-hydroxylase.

Prolyl 4-hydroxylase, the key enzyme of collagen synthesis, is an alpha2beta2 tetramer, the beta subunit of which is protein disulfide isomerase (PDI). Coexpression of the human alpha subunit and PDI in Pichia produced trace amounts of an active tetramer. A much higher, although still low, assembly level was obtained using a Saccharomyces pre-pro sequence in PDI. Coexpression with human type III procollagen unexpectedly increased the assembly level 10-fold, with no increase in the total amounts of the subunits. The recombinant enzyme was active not only in Pichia extracts but also inside the yeast cell, indicating that Pichia must have a system for transporting all the cosubstrates needed by the enzyme into the lumen of the endoplasmic reticulum. The 4-hydroxyproline-containing procollagen polypeptide chains were of full length and formed molecules with stable triple helices even though Pichia probably has no Hsp47-like protein. The data indicate that collagen synthesis in Pichia, and probably also in other cells, involves a highly unusual control mechanism, in that production of a stable prolyl 4-hydroxylase requires collagen expression while assembly of a stable collagen requires enzyme expression. This Pichia system seems ideal for the high-level production of various recombinant collagens for numerous scientific and medical purposes.     

人重组白蛋白基因在巴斯德毕赤酵母中的高效表达

The yeast Pichia pastoris was transformed by the multi\|copy Pichia expression vector that can express secreted human albumin.The high level expression of cell line was selected after screening.The expression of human recombinant albumin in Pichia pastoris induced by different methods were compared.The retio of secreted human albumin is 80% in total secreted proteins and the expression level reaches as high as is 10g/L.     

巴斯德毕赤酵母表达系统研究进展

巴斯德毕赤酵母表达系统现在已经发展成为一种高效的外源蛋白基因优秀表达系统,该系统具有高表达、高稳定、高分泌、容易放大和成本低等优点,目前已有多种外源蛋白基因在该系统中实现高效表达,对巴斯德毕赤酵母表达系统的进一步研究将会促进其大规模的工业化应用。     

Serological relationships among some Pichia species.

Antigenic analyses of five species of the genus Pichia were carried out for taxonomic study by the slide agglutination method using monospecific and absorbed antisera and the agglutinin absorption technique. Comparative studies were also performed with a few strains of each of the same species and their classifications are discussed with respect to the antigenic structures and the patterns of proton magnetic resonance (PMR) spectra of their cell wall polysaccharides. ichia delftensis and Pichia zaruensis possessed thermostable antigens 1,2,5 and 11, and the former had also thermoabile antigen m. Both species were closely related to Candida krusei. Pichia toletana possessed thermostable antigens 1,2,5,11,17 and 49. Pichia bovis contained thermostable antigens 1,2,14,15,16,20 and 21, and it was related to most species of the genus Hansenula, although assimilation of potassium nitrate was negative. Finally, Pichia etchellsii possessed thermostable antigens 1,2,3,4,9 and 14, and was closely related to Pichia vini. Patterns of PMR spectra of mannans of these species also supported their serological relationships. Therfore, P. delftensis, P. zaruensis and P. etchellsii are considered to be the synonyms of Pichia fluxuum, Pichia dispora and P. vini respectively, although P. toletanan and P. bovis are independent species.     

Phylogenetic relationships among species of Pichia, Issatchenkia and Williopsis determined from multigene sequence analysis, and the proposal of Barnettozyma gen. nov., Lindnera gen. nov. and Wickerhamomyces gen. nov

Relationships among species assigned to the yeast genera Pichia, Issatchenkia and Williopsis , which are characterized by the ubiquinone CoQ-7 and inability to utilize methanol, were phylogenetically analyzed from nucleotide sequence divergence in the genes coding for large and small subunit rRNAs and for translation elongation factor-1α. From this analysis, the species separated into five clades. Species of Issatchenkia are members of the Pichia membranifaciens clade and are proposed for transfer to Pichia . Pichia dryadoides and Pichia quercuum are basal members of the genus Starmera . Williopsis species are dispersed among hat-spored taxa in each of the remaining three clades, which are proposed as the new genera Barnettozyma, Lindnera and Wickerhamomyces . Lineages previously classified as varieties of Pichia kluyveri , ' Issatchenkia ' scutulata, Starmera amethionina and ' Williopsis ' saturnus are elevated to species rank based on sequence comparisons.     

The entry of D-ribose into some yeasts of the genus Pichia.

The utilization of D-ribose by yeasts of the genus Pichia was examined with respect to aerobic growth, respiration and entry of ribose into the cells. Pichia etchellsii (CBS2011) could respire D-ribose, but not use it for aerobic growth. Pichia fermentans (CBS187) neither respired nor grew on D-ribose, though it entered the cells of this yeast either by simple diffusion, or possibly, by the D-glucose carrier, this having a very low affinity for D-ribose. Pichia pinus (CBS5097) respired and grew on D-ribose; kinetic evidence is given for this yeast having two ribose carriers, one inducible and the other constitutive.     

毕赤酵母工程菌高密度发酵研究与进展

毕赤酵母表达系统是近年来发展最为迅速的一种新型外源蛋白真核表达系统,被广泛应用于多种不同领域且成功表达了许多基因工程产品。高密度发酵技术已被广泛运用到毕赤酵母工程菌发酵工程当中。主要从毕赤酵母的表达常用菌株、载体及表型等方面介绍了其表达系统,从外源基因自身的特性、培养基的组成、温度、pH、溶氧量及补料流加策略方面阐述了对毕赤酵母高密度发酵的过程及蛋白质表达结果的影响,并对毕赤酵母工程菌高密度发酵进行了展望,为其今后的研究及应用提供借鉴。     

Candida easanensis sp. nov., Candida pattaniensis sp. nov. and Candida nakhonratchasimensis sp. nov., three new species of yeasts isolated from insect frass in Thailand

Six strains of anamorphic yeasts isolated from insect frass collected in several regions of Thailand were assigned to the genus Candida based on the conventional taxonomic criteria used for yeast classification. These strains have Q-7 as the major ubiquinone and are suggested to have close relationships to the genus Pichia. Three strains, ST-225, ST-228 and ST-229, have identical nucleotide sequences in the D1/D2 domain of 26S rDNA and are closely related to Pichia japonica, but differ by six nucleotides (1.1% ) from this species. These three strains are considered to represent a single new species, which is described as Candida easanensis sp. nov. Two strains, ST-311 and ST-320, have identical sequences in the D1/D2 domain and resemble Pichia veronae and Pichia fabianii but differ from them by nine nucleotides (1.6%) in D1/D2 sequences. The two strains are described as Candida pattaniensis sp. nov. The remaining strain, ST-37, is related to Pichia americana and Pichia bimundalis but differs by six(1.1%) and seven (1.2%) nucleotides from these species, respectively. This strain is described as Candida nakhonratchasimensis sp. nov.     

木质素过氧化物酶基因（LipH8）的克隆及在甲醇毕赤酵母中的表达

以黄孢原毛平革菌 (Phanerochaetechrysosporium)RNA为模板 ,克隆LipH8基因片段 ,研究LipH8基因在甲醇毕赤酵母中的表达。构建了甲醇酵母表达质粒pMETA_LipH8载体 ,并将其线性化后用电穿孔法导入PichiamethabolicaPMAD16 ,部分阳性克隆的PCR结果表明LipH8基因已经整合到甲醇毕赤酵母染色体上 ,经摇瓶培养筛选出表达水平较高的酵母工程菌株。胞外木质素过氧化物酶活力达 932U L。     

巴曲酶在毕赤酵母中的高效表达

目的研究巴曲酶在毕赤酵母菌中的表达。方法按Pichiapastoris偏好密码子人工合成巴曲酶全基因,克隆到酵母分泌型表达载体pPICZaA中,将重组载体酶切线性化后经电转化转入X-33。筛选鉴定转化子．经摇瓶发酵甲醇诱导,酵母菌分泌表达有凝血活性的巴曲酶。经SDS-PAGE电泳确定其分子量为33．0 kDa．免疫印迹证明重组巴曲酶具有天然巴曲酶的免疫活性。结果经发酵条件的优化．发酵罐的表达量达到25000Ku／L发酵液。从每升发酵液中可纯化出11．0mg重组巴曲酶。结论巴曲酶毕氏酵母菌成功的构建．为重组巴曲酶止血药的开发奠定了基础。     

A phylogenetic study of ubiquinone Q-8 species of the genera Candida,Pichia, and Citeromyces based on 18S ribosomal DNA sequence divergence

To clarify phylogenetic relationships among species of the anamorphic ascomycetous genus Candida with ubiquinone Q-8, we determined complete sequences of 18S ribosomal RNA genes (18S rDNAs) from the type strains of 20 species of the genus Candida and 7 of the teleomorphic ascomycetous genera Pichia and Citeromyces, which have Q-8 as the major ubiquinone. Q-8-forming Candida species were divided into six clusters and were phylogenetically distant from a group of Candida species that included the type species of the genus. One Q-8-forming species from each of the genera Pichia, Citeromyces, or Clavispora was included in five of six clusters. Cluster 1 comprised C. ishiwadae, C. ernobii, C. karawaiewii, C. anatomiae, C. populi, and Pichia holstii. Cluster 2 comprised C. globosa and its teleomorph, Citeromyces matritensis. Cluster 3 comprised C. molischiana and Pichia capsulata. Cluster 4 comprised C. silvanorum, C. sequanensis, C. fennica, C. entomophila, C. homilentoma, C. rhagii, C. gotoi, and Pichia burtonii. Cluster 5 comprised C. fructus, C. musae, and C. lusitaniae (anamorph of Clavispora lusitaniae). Cluster 6 comprised C. stellata, C. lactiscondensi, C. galacta, and C. incommunis and was a heterogeneous group with large interspecific divergence. Pichia pastoris was quite divergent and phylogenetically distant from other Pichia species examined. Pichia methanolica and its synonym, P. cellobiosa, which have both Q-7 and Q-8 as major ubiquinones, were closely associated with Q-7-forming Williopsis salicorniae. Based on this comparative analysis of 18S rDNA sequences, it is evident that Q-8 Candida species and Q-8 Pichia species are polyphyletic.     

Biocontrol of mold growth in high-moisture wheat stored under airtight conditions by Pichia anomala, Pichia guilliermondii, and Saccharomyces cerevisiae.

Pichia anomala inhibits the growth of Penicillium roqueforti and Aspergillus candidus on agar. In this investigation, antagonistic activity on agar against 17 mold species was determined. The abilities of Pichia anomala, Pichia guilliermondii, and Saccharomyces cerevisiae to inhibit the growth of the mold Penicillium roqueforti in nonsterile high-moisture wheat were compared by adding 10(3) Penicillium roqueforti spores and different amounts of yeast cells per gram of wheat. Inoculated grain was packed in glass tubes, incubated at 25 degrees C with a restricted air supply, and the numbers of yeast and mold CFU were determined on selective media after 7 and 14 days. Pichia anomala reduced growth on agar plates for all of the mold species tested in a dose-dependent manner. Aspergillus fumigatus and Eurotium amstelodami were the most sensitive, while Penicillium italicum and Penicillium digitatum were the most resistant. Pichia anomala had the strongest antagonistic activity in wheat, with 10(5) and 10(6) CFU/g completely inhibiting the growth of Penicillium roqueforti. Inhibition was least pronounced at the optimum temperature (21 degrees C) and water activity (0.95) for the growth of Penicillium roqueforti. Pichia guilliermondii slightly reduced the growth of Penicillium roqueforti in wheat inoculated with 10(5) and 10(6) yeast CFU/g. S. cerevisiae inhibited mold growth only weakly at the highest inoculum level. Pichia anomala grew from 10(3) to 10(7) CFU/g of wheat in 1 week. To reach the same level, Pichia guilliermondii had to be inoculated at 10(4) CFU while S. cerevisiae required an inoculum of 10(5) CFU to reach 10(7) CFU/g of wheat.     

表达乙肝病毒包膜中蛋白的嗜甲醇毕赤酵母菌株的构建

巴斯德毕赤酵母是一种很有潜力的真核表达体系。本文报告将已克隆的乙型肝炎病毒ｐｒｅＳ２－Ｓ基因亚克隆于巴斯德毕赤酵母胞内表达质粒ｐＰＩＣ３,构建重组ｐＰＩＣ３／ｐｒｅＳ２－Ｓ质粒,经酶切线性化后,将其用电转化导入酵母细胞内,经ＰＣＲ及ｄｏｔｂｌｏｔ检测,挑选出在染色体上稳定整合了乙肝病毒包膜中蛋白编码基因的嗜甲醇毕赤酵母菌株,为高效表达乙肝病毒包膜中蛋白奠定了基础     

杂色云芝漆酶基因(Lcc1)的克隆及在甲醇毕赤酵母中的表达

以白腐菌杂色云芝Coriolus versicolor RNA为模板,通过RT-PCR获得漆酶Leel基因的cDNA片段。构建了甲醇酵母表达质粒pMETA-Lccl载体,并将其线性化后用电穿孔法导入Pichia methabolica PMAD16,部分阳性克隆的PCR结果表明Lccl基因已经整合到甲醇毕赤酵母染色体上,经摇瓶培养筛选出表达水平较高的酵母工程菌株。漆酶酶活力达53U/L