Da Vinci's yeast: Blastobotrys davincii f.a., sp. nov

A new species of the yeast genus Blastobotrys was discovered during a worldwide survey of culturable xerophilic fungi in house dust. Several culture-dependent and independent studies from around the world detected the same species from a wide range of substrates including indoor air, cave wall paintings, bats, mummies, and the iconic self-portrait of Leonardo da Vinci from ca 1512. However, none of these studies identified their strains, clones, or OTUs as Blastobotrys. We introduce the new species as Blastobotrys davincii f.a., sp. nov. (holotype CBS H-24879) and delineate it from other species using morphological, phylogenetic, and physiological characters. The new species of asexually (anamorphic) budding yeast is classified in Trichomonascaceae and forms a clade along with its associated sexual state genus Trichomonascus. Despite the decade-old requirement to use a single generic name for fungi, both names are still used. Selection of the preferred name awaits a formal nomenclatural proposal. We present arguments for adopting Blastobotrys over Trichomonascus and introduce four new combinations as Blastobotrys allociferrii (≡ Candida allociferrii), B. fungorum (≡ Sporothrix fungorum), B. mucifer (≡ Candida mucifera), and Blastobotrys vanleenenianus (≡ Trichomonascus vanleenenianus). We provide a nomenclatural review and an accepted species list for the 37 accepted species in the Blastobotrys/Trichomonascus clade. Finally, we discuss the identity of the DNA clones detected on the da Vinci portrait, and the importance of using appropriate media to isolate xerophilic or halophilic fungi.     

The yeast community of Conotelus sp. (Coleoptera: Nitidulidae) in Brazilian passionfruit flowers (Passiflora edulis) and description of Metschnikowia amazonensis sp. nov., a large-spored clade yeast

Species of the nitidulid beetle Conotelus found in flowers of Convolvulaceae and other plants across the New World and in Hawaii consistently harbour a yeast community dominated by one or more large-spored Metschnikowia species. We investigated the yeasts found in beetles and flowers of cultivated passionfruit in Rondônia state, in the Amazon biome of Brazil, where a Conotelus species damages the flowers and hinders fruit production. A sample of 46 beetles and 49 flowers yielded 86 and 83 yeast isolates, respectively. Whereas the flower community was dominated by Kodamaea ohmeri and Kurtzmaniella quercitrusa, the major yeasts recovered from beetles were Wickerhamiella occidentalis, which is commonly isolated from this community, and a novel species of large-spored Metschnikowia in the arizonensis subclade, which we describe here as Metschnikowia amazonensis sp. nov. Phylogenetic analyses based on barcode sequences (ITS-D1/D2) and a multigene alignment of 11,917 positions (genes ura2, msh6, and pmt2) agreed to place the new species as a sister to Metschnikowia arizonensis, a rare species known only from one locality in Arizona. The two form sterile asci when mated, which is typical of related members of the clade. The α pheromone of the new species is unique but typical of the subclade. The type of M. amazonensis sp. nov. is UFMG-CM-Y6309^T (ex-type CBS 16156^T, mating type a ), and the designated allotype (mating type α) is UFMG-CM-Y6307^A (CBS 16155^A). MycoBank MB 833560.     

Isolation of Pseudozyma churashimaensis sp. nov., a novel ustilaginomycetous yeast species as a producer of glycolipid biosurfactants, mannosylerythritol lipids

An ustilaginomycetous anamorphic yeast species isolated from the leaves of Saccharum officinarum (sugarcane) in Okinawa, Japan, was identified as a novel Pseudozyma species based on morphological and physiological aspects and molecular taxonomic analysis using the D1/D2 domains of the large subunit (26S) rRNA gene and the internal transcribed spacer 1 (ITS1)-5.8S-ITS2 regions. The name Pseudozyma churashimaensis sp. nov. was proposed for the novel species, with JCM 16988(T) as the type strain. Interestingly, P. churashimaensis was found to produce glycolipid biosurfactants, a mixture of mannosylerythritol lipids (MELs), including a novel tri-acetylated derivative (MEL-A2), from glucose. The observed critical micelle concentration (CMC) and the surface tension at CMC of MEL-A2 were 1.7 × 10?? M and 29.2 mN/m, respectively. Moreover, on a water-penetration scan, MEL-A2 efficiently formed different lyotropic liquid crystalline phases, including the lamella phase at a wide range of concentrations, indicating its excellent surface-active and self-assembling properties. The novel strain of the genus Pseudozyma should thus facilitate the application of glycolipid biosurfactants in combination with other MEL producers.     

硇洲马尾藻的营养成分分析与评价

对硇洲马尾藻的常规营养成分、不溶性膳食纤维、氨基酸及矿质元素进行分析测定.结果显示,碳水化合物、蛋白质和灰分是硇洲马尾藻的主要成分,占藻体干重的85%左右.其中不溶性膳食纤维占藻体干重的10.88%,蛋白质占13.95%,必需氨基酸丰富,占氨基酸总量的41%,必需氨基酸与非,必需氨基酸的比值为0.69.脂肪含量为2.4%,不饱和脂肪酸含量高.矿质元素含量丰富,尤其是铁和锌含量高.     

Paenibacillus bovis sp.nov.BD3526作为益生菌的潜力

对Paenibacillus bovis sp.nov.BD3526作为益生菌的潜力进行了体外活性初步研究。采用模拟胃液、肠液、不同浓度的胆盐环境,测定BD3526菌株在酸性及高胆盐环境的存活率,并测试BD3526对金黄色葡萄球菌、藤黄、枯草芽孢杆菌的抑制作用。结果表明,BD3526可以耐受pH值为2.0、3.0、4.0的人工胃液、pH8.0的模拟肠液以及0.1%、0.2%、0.3%的胆盐环境;对金黄色葡萄球菌、藤黄、枯草芽孢杆菌有显著的抑制能力。说明BD3526在人工消化液环境中具有良好的存活能力,不具有溶血作用;可引起敏感菌细胞渗漏,达到杀灭部分细菌,包括金色葡萄球菌的作用,因此,该菌具备作为益生菌应用的潜力。     

Paenibacillus tyraminigenes sp. nov. isolated from Myeolchi-jeotgal, a traditional Korean salted and fermented anchovy

A bacterial strain H3029, a gram-positive, rod-shaped, oxidase-negative, endospore-forming bacterium that characteristically produces tyramine from tyrosine, was isolated from a Myeolchi-jeotgal, a traditional Korean salted and fermented anchovy (Engraulis japonicus). The H3029 strain showed a high ability to produce 4140 microg/ml of tyramine from the culture broth containing 5000 microg/ml tyrosine. On the other hand, the strain produced a relatively low level of other putrefactive amines, at 973 microg/ml of putrescine and 147 microg/ml of cadaverine from the media, with each 5000 microg/ml of ornithine hydrochloride and lysine hydrochloride. The H3029 strain produced no detectable level of histamine (detection limit of 4 microg/ml) from the media containing 5000 microg/ml of histidine hydrochloride. Meanwhile, tyramine, the main product of the strain, showed the antimicrobial activity at the level of over 1 mg/disk against Staphylococcus aureus by agar diffusion test, and the mutagenicity in Ames test at 0.1 mg/plate using Salmonella typhimurium TA98 and TA1535. On the basis of the polyphasic taxonomic study, the H3029(T) strain was assigned a novel species of the genus Paenibacillus as Paenibacillus tyraminigenes sp. nov. The type strain of which is strain H3029(T) (=KCTC 10694BP(T)).     

响应面法优化硇洲马尾藻多糖提取工艺

为优化硇洲马尾藻多糖提取工艺,在单因素试验基础上,选择提取温度,提取时间,料液比为自变量,多糖提取率为响应值,利用Box-Benhnken中心组合试验和响应面分析法,研究各自变量交互作用及其对硇洲马尾藻多糖得率的影响,模拟得到二次多项式回归方程的预测模型,并确定硇洲马尾藻多糖提取工艺最佳条件为:料液比为1:21(g/mL),提取温度为90.7℃,提取时间为5.14 h,在此条件下,硇洲马尾藻多糖得率达到6.39%。     

酶法合成癸酸甘油酯及其产物分布的研究

以固定化假丝酵母脂肪酶为催化剂,研究了无溶剂体系中甘油和癸酸直接酯化合成癸酸甘油酯的反应条件.考察了反应加酶量,底物摩尔比,温度,甘油含水量,反应过程中脱水方式等因素对癸酸转化率及最终产物分布的影响.结果表明:织物直接吸附假丝酵母发酵液制备的固定化脂肪酶能有效地催化合成癸酸甘油酯.反应的最优条件为:甘油与癸酸的摩尔比为1:1.5,反应温度为40℃,甘油含水量为4%,加酶量为0.25g/g癸酸.在最优反应条件下,癸酸转化率可达到98%.经过处理,固定化脂肪酶可重复使用4次以上.     

“甜蜜家族”添新丁 功能性甜食正流行

<正> 甜食业经过2004年的奶糖热,2005年的胶母糖热,在2006～2007年开始了理性调整时期,目前该行业的流行趋势层出不穷。从包装上看,有一口装、小包装和多形式包装;从口感方面来看,分高口感型食品和非高口感型食品从功效上看,又有功能性和非功能性之分。功能性甜食是近几年逐渐在市场上崭露头角且较有发展潜力的主力品种之     

芽孢杆菌Bacillus sp.nov.SK006产纤溶酶发酵条件的研究

利用实验室自行从亚洲传统发酵食品虾酱中筛选到一株产纤溶酶能力较强的芽孢杆菌(Bacillus sp.nov.SK006)进行发酵,考察培养基组成及培养条件对该菌种产纤溶酶能力的影响.结果表明该菌株产酶最佳的组分(质量浓度)为:葡萄糖20 g/L,胰蛋白胨30 g,L,Na2HPO4·12H2012 g/L,NaH1PO4.2H20 1.3 g/L,Mgs04·7H20 1.0 g/L;培养条件:种龄18 h,接种量3%,发酵周期24 h,初始pH为7.0,摇床转速180 r/min,发酵温度37℃,在此条件下发酵液纤溶活性(以Plasmin为标准)达2.63 U/mL,优化后纤维蛋白溶解酶的产量是优化前0.70 U/mL的3.76倍.     

Isolation and sequencing of the Candida albicans MSI3, a putative novel member of the HSP70 family

We have reported previously that the expression of CGR1 increased at an early stage of the yeast-mycelial transition (morphogenesis) in Candida albicans. We now show that Cgr1p interacts in a yeast two-hybrid system with the C. albicans Msi3p (CaMsi3p), a putative novel member of the heat shock protein 70 (HSP70) family. The DNA sequence of CaMSI3 encodes a predicted protein of 702 amino acids with a molecular mass of 78.6 kDa. The amino acid sequence of CaMsi3p is 63% identical to Msi3p/Sse1p of the HSP70 family of Saccharomyces cerevisiae. Further, CaMSI3 complemented the temperature-sensitive phenotype of the msi3(-) mutant of S. cerevisiae. Other heat shock proteins of C. albicans are required for morphogenesis and are highly antigenic. These observations suggest that CaMSI3 may well provide functions for this organism unrelated to a heat shock function. The DDBJ Accession No. for the sequence reported in this paper is AB061274.     

HST1, a new member of the SIR2 family of genes

A novel Saccharomyces cerevisiae gene, HST1, was identified from among anonymous cDNAs and the complete corresponding genomic clone was isolated and sequenced. HST1 is very closely related to SIR2, showing 71% sequence identity over 84% of its length. Polymerase chain reaction with degenerate primers on S. cerevisiae DNA identified three additional SIR2-related genes designated HST2, HST3 and HST4. The sequences of HST2, HST3 and HST4 correspond to sequences previously released by the S. cerevisiae genome sequencing project as U33335, NCBI gi:965078; X87331, NCBI gi:829135; and Z48784, YD9346.03, respectively. Disruption of HST1 has shown no phenotype with respect to mechanisms in which SIR2 has a role, namely, regional silencing of HMLα, or in rDNA recombination. The sequence of HST1 has been deposited in the DDBJ, EMBL and GenBank at NCBI database under Accession Number L47120.     

假丝酵母99-125发酵生产脂肪酶工艺研究

对假丝酵母99-125发酵生产脂肪酶工艺进行了研究,实现了5m3发酵罐的稳定生产,确定最佳通气比(v/v)和搅拌转速分别为0.8∶1和122r/min,发酵后期补入0.5%的豆油对产酶有促进作用,在103h达到最高酶活为7 240U/mL,用3%的大豆分离蛋白和2%的大豆生物素组合替代豆粕作为氮源,可以提高发酵活力12%,达到8 179U/mL,发酵残渣量减少20%,最终罐批获得的酶活总量提高了近15%。     

常用食品添加剂对常山胡柚色素稳定性的影响

以超临界CO2萃取得到的常山胡柚外果皮色素粗产品为原料,研究常见的食品添加剂对常山胡柚色素稳定性的影响。结果表明：甜味剂蔗糖和葡萄糖、防腐剂苯甲酸钠、酸味剂柠檬酸、还原剂Na2SO3等对常山胡柚色素有护色作用;稳定剂和凝固刑氯化钙、品质改良剂六偏磷酸钠、氧化剂H2O2等对常山胡柚色素有褪色作用;大多数金属离子对常山胡柚色素无不良影响。     

Yeast communities associated with cacti in Brazil and the description of Kluyveromyces starmeri sp. nov. based on phylogenomic analyses

Yeast communities associated with cacti were studied in three ecosystems of Southeast, Central and North Brazil. A total of 473 yeast strains belonging to 72 species were isolated from 190 samples collected. Cactophilic yeast species were prevalent in necrotic tissues, flowers, fruits and insects of cacti collected in Southeast and North Brazil. Pichia cactophila, Candida sonorensis and species of the Sporopachydermia complex were the most prevalent cactophilic species in Southeast and Central regions. Kodamaea nitidulidarum, Candida restingae and Wickerhamiella cacticola were frequently associated with cactus flowers and fruits. The diversity of yeasts associated with the substrates studied was high. Twenty-one novel species were found. One is described here as Kluyveromyces starmeri sp. nov. based on 21 isolates obtained from necrotic tissues, flowers, fruits and associated insects of the columnar cacti Cereus saddianus, Micranthocereus dolichospermaticus and Pilosocereus arrabidae in two different ecosystems in Brazil. Phylogenetic analyses of sequences encoding the gene of the small subunit (SSU) rRNA gene, the internal transcribed spacer, the 5.8S rRNA gene and the D1/D2 domains of the large subunit (LSU) rRNA showed that the species is related to Kluyveromyces dobzhanskii, Kluyveromyces lactis and Kluyveromyces marxianus. Phylogenomic analyses based on 1264 conserved genes shared among the new species and 19 other members of the Saccharomycetaceae confirmed this phylogenetic relationship. The holotype is K. starmeri sp. nov. CBS 16103^T (=UFMG-CM-Y3682^T). The Mycobank number is MB 836817.     

类芽孢杆菌BD3526在无氮固体培养基上产胞外多糖的研究

为了研究Paenibacillus bovis sp.nov BD3526在无氮培养基上产的胞外多糖的结构和生物活性,本文制得了其在无氮培养基平板上分泌的胞外多糖,并用离子交换层析法对此胞外多糖进行分离纯化,得到了一个主要组分的纯品（F1）;凝胶渗透色谱（GPC）的结果显示F1的分子量是3.76×107Da,用红外光谱（FT-IR）和核磁共振氢谱（1H NMR）表征其化学结构,结果表明F1是直链的左聚糖;热重分析（TGA）和差示扫描量热法（DSC）的结果表明左聚糖具有良好的热稳定性;动态光散射仪（DLS）测定其在水溶液中形成的聚集体的粒径约为163.2 nm,而透射电镜（TEM）照片表明其在水溶液中呈紧实的球型,粒径在50¹00 nm;最后采用细胞实验评价其免疫增强作用,体外实验结果表明此左聚糖在低浓度时即可显著促进脾细胞的增殖,具有很强的免疫增强活性。此左聚糖可以作为免疫增强剂应用于功能性食品领域。