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991.
Chiaki Ogino Shunichi Kuroda Shinji Tokuyama Akihiko Kondo Nobuaki Shimizu Katsuyuki Tanizawa Hideki Fukuda 《Journal of Molecular Catalysis .B, Enzymatic》2003,23(2-6):107-115
This review is focusing on an industrially important enzyme, phospholipase D (PLD), exhibiting both transphosphatidylation and hydrolytic activities for various phospholipids. The transphosphatidylation activity of PLD is particularly useful for converting phosphatidylcholine (PC) into other phospholipids. During the last decade, the genes coding for PLD have been identified from various species including mammals, plants, yeast, and bacteria. However, detailed basic and applied enzymological studies on PLD have been hampered by the low productivity in these organisms. Efficient production of a recombinant PLD has also been unsuccessful so far. We recently isolated and characterized the PLD gene from Streptoverticillium cinnamoneum, producing a secretory PLD. Furthermore, we constructed an overexpression system for the secretory enzyme in an active and soluble form using Streptomyces lividans as a host for transformation of the PLD gene. The Stv. cinnamoneum PLD was proven to be useful for the continuous and efficient production of phosphatidylethanolamine (PE) from phosphatidylcholine. Thus, the secretory PLD is a promising catalyst for synthesizing new phospholipids possessing various polar head groups that show versatile physiological functions and may be utilized in food and pharmaceutical industries. 相似文献
992.
Shoot damage by Tomicus sp. (Coleoptera: Scolytidae) and effect on Pinus yunnanensis resistance to subsequent reproductive attacks in the stem 总被引:3,自引:0,他引:3
Abstract 1 In South‐western China, Yunnan pines Pinus yunnanensis, suffer considerable damage from an undescribed Tomicus sp. previously thought to be T. piniperda. 2 To assess the effect of shoot maturation feeding (during which an aggregation process appears to occur) on host resistance to attacks on the bole, the relationships between shoot damage, bole attack density and tree survival were studied. 3 Attack distribution in the crown and in the stem did not vary between killed and surviving trees, indicating that mortality is determined by the quantity of attacks. 4 The level of shoot damage and bole attack density were positively and linearly correlated. This can be explained by the fact that bole attacks are caused by beetles coming from the crown of the same tree. 5 A critical threshold of bole attack density (around 80 attacks/m2) above which trees die was observed. However, because attacks continue after this threshold is reached, the density of failed attacks on the killed trees was used as an estimator of the threshold density. It decreased when shoot damage increased. 6 The existence of a critical threshold of shoot damage (60% damaged shoots) was also demonstrated. Above this threshold, stem attack density was always sufficiently high to kill trees. 7 The results emphasize that concentration of shoot attacks is the main reason for the extensive tree damage observed in China. 8 A model of relationships between shoot and stem attacks is proposed, suggesting that management to reduce shoot attacks would protect trees from dying by both decreasing the number of bole attacks and raising the threshold for successful attack density on the bole to levels that could not be attained. 相似文献
993.
为了提高小鼠金属硫蛋白-Ⅰ(mMT-Ⅰ)在鱼腥藻7120(Anabaena sp.PCC 7120)中的表达量、便于表达产物的分离纯化,构建了新的穿梭融合表达载体pKG-MT.通过pKG-MT,mMT-Ⅰ cDNA在tac启动子的调控下,以与谷胱甘肽转硫酶(GST)C-末端相融合(GST-MT)的形式在鱼藻中表达.SDS-PAGE结果显示在异丙基硫代-β-D-半乳糖苷(IPTG)诱导下GST-MT在鱼腥藻中表达.经谷胱甘肽亲合层析,从转基因藻中分离、纯化得到GST-MT.利用GSTC-末端的凝血酶酶切位点,用凝血酶对GST-MT进行柱上酶切,经Sephadex GS0除去凝血酶得到mMT-Ⅰ.SDS-PAGE表明纯化得到所要的目标产物;ELISA测定结果显示从每克转基因藻(鲜重)中可纯化得到0.9 mg mMT-Ⅰ;原子吸收测定表明纯化得到的mMT-Ⅰ的镉离子结合能力接近于天然MT. 相似文献
994.
Pham Minh Duc Kishio Hatai Osamu Kurata Kozue Tensha Uchida Yoshitaka Takashi Yaguchi Shun-Ichi Udagawa 《Mycopathologia》2009,167(5):229-247
Two fungal pathogens of the mantis shrimp (Oratosquilla oratoria) in Yamaguchi and Aichi Prefectures, Japan are described as the new species Plectosporium oratosquillae and Acremonium sp. (a member of the Emericellopsis marine clade). Both fungi infect the gills of the mantis shrimp, which become brown or black due to melanization. The former
species is characterized by its slow growth on artificial seawater yeast extract peptone glucose (PYGS) agar, pale yellow
to pale orange or grayish yellow colonies, short cylindrical solitary phialides with a wavy tip, and one-celled ellipsoidal
conidia. Although lacking the two-celled conidia demonstrated by the type species Plectosporium tabacinum, the taxonomic placement of the new species was confirmed by DNA sequence analysis of the internal transcribed spacer (ITS)
region of ribosomal DNA (ITS1, 5.8S rDNA and ITS2). Acremonium sp., the other causal pathogen, differs from P. oratosquillae by its fast growth on PYGS agar, pale orange to salmon-colored colonies, long, slender conidiophores consisting of solitary
phialides with tips lacking an undulate outline, and typically cylindrical conidia. Analysis of ITS and β-tubulin gene sequences
placed this fungus within the phylogenetically distinct Emericellopsis (anam. Acremonium) marine clade. Various physiological characteristics of both pathogens were also investigated. This is the first report of
a fungal infection found on the mantis shrimp in Japan. 相似文献
995.
996.
Chitwadee Phithakrotchanakoon Ratama Daduang Arinthip Thamchaipenet Thidarat Wangkam Toemsak Srikhirin Lily Eurwilaichitr Verawat Champreda 《Applied microbiology and biotechnology》2009,82(1):131-140
A polyhydroxyalkanote depolymerase gene from Thermobifida sp. isolate BCC23166 was cloned and expressed as a C-terminal His6-tagged fusion in Pichia pastoris. Primary structure analysis revealed that the enzyme PhaZ-Th is a member of a proposed new subgroup of SCL-PHA depolymerase
containing a proline–serine repeat linker. PhaZ-Th was expressed as two glycosylated forms with apparent molecular weights
of 61 and 70 kDa, respectively. The enzyme showed esterase activity toward p-nitrophenyl alkanotes with V
max and K
m of 3.63 ± 0.16 μmol min−1 mg−1 and 0.79 ± 0.12 mM, respectively, on p-nitrophenyl butyrate with optimal activity at 50–55°C and pH 7–8. Surface plasmon resonance (SPR) analysis demonstrated that
PhaZ-Th catalyzed the degradation of poly-[(R)-3-hydroxybutyrate] (PHB) films, which was accelerated in (R)-3-hydroxyvalerate copolymers with a maximum degradation rate of 882 ng cm−2 h−1 for poly[(R)-3-hydroxybutyrate-co-3-hydroxyvalerate] (12 mol% V). Surface deterioration, especially on the amorphous regions of PHB films
was observed after exposure to PhaZ-Th by atomic force microscopy. The use of P. pastoris as an alternative recombinant system for bioplastic degrading enzymes in secreted form and a sensitive SPR analytical technique
will be of utility for further study of bioplastic degradation. 相似文献
997.
Luo H Wang Y Wang H Yang J Yang Y Huang H Yang P Bai Y Shi P Fan Y Yao B 《Applied microbiology and biotechnology》2009,82(3):453-461
Using degenerate polymerase chain reaction (PCR) and thermal asymmetric interlaced PCR, a 1,347-bp full-length complementary
DNA fragment encompassing the gene man5A, which encodes a 429-amino acid β-mannanase with a calculated mass of 46.8 kDa, was cloned from acidophilic Bispora sp. MEY-1. The deduced amino acid sequence (catalytic domain) displayed highest identity (54.1%) with the Emericella nidulans endo-β-1,4-d-mannanase, a member of the glycoside hydrolase family 5. Recombinant MAN5A was overexpressed in Pichia pastoris, and its activity in the culture medium reached 500 U ml−1. The enzyme was acidophilic, with highest activity at pH 1.0–1.5, lower than any known mannanases, and optimal temperature
for activity was 65°C. MAN5A had good pH adaptability, excellent thermal and pH stability, and high resistance to both pepsin
and trypsin. The specific activity, K
m, and V
max for locust bean gum substrate was 3,373 U mg−1, 1.56 mg ml−1, and 6,587.6 μmol min−1 mg−1, respectively. The enzymatic activity was not significantly affected by ions such as Ca2+, Cr3+, Co2+, Zn2+, Na+, K+, and Mg2+ and enhanced by Ni2+, Fe3+, Mn2+ and Ag+. These favorable properties make MAN5A a potential candidate for use in various industrial applications. 相似文献
998.
Gerald Mayr 《Pal?ontologische Zeitschrift》2009,83(2):247-254
The early Oligocene Boom Formation in Belgium yielded many avian remains from the Rupelian unit-stratotype, most of which have remained unstudied so far. Here, I describe a small loon (Gaviiformes) and a new species of large owl (Strigiformes) that are represented by associated bones of a single individual each. The loon, of which wing and pectoral girdle bones are preserved, is assigned to Colymboides (?) metzleri, a species previously known from a partial skeleton from the Rupelian of Germany. The owl is based on a tarsometatarsus and distal tibiotarsus and described as a new species, Selenornis steendorpensis. It constitutes the most substantial fossil record of the taxon Selenornis, which was before known from a distal tibiotarsus from an unknown horizon of the Quercy fissure fillings in southwestern France. It is detailed that there are differences in the higher level taxonomic composition of the known early Oligocene avifaunas of northern and southern Europe, which may reflect true zoogeographic facts owing to a different climate and vegetation. 相似文献
999.
Luciana Albuquerque Catarina Ferreira David Tomaz Igor Tiago António Veríssimo Milton S. da Costa M. Fernanda Nobre 《Systematic and applied microbiology》2009
Four red-pigmented isolates, with optimum growth temperatures of approximately 55–60 °C and an optimum pH for growth between 7.5 and 8.5, were recovered from hot springs in Central France. Phylogenetic analysis of the 16S rRNA gene sequences showed that these organisms represented a new species of the genus Meiothermus. The new isolates could be distinguished from other strains of the species of the genus Meiothermus primarily by the glycolipid profile and fatty acid composition because these organisms lacked the hydroxy fatty acids and the glycolipid variant GL-1a found in all other isolates of the species of Meiothermus examined. On the basis of the results presented here we propose the name Meiothermus rufus for the new species, which is represented by strains CAL-4T (=DSM 22234T=LMG 24878T) and CAL-12 (=DSM 22235=LMG 24879). We also propose emending the genus Meiothermus to include strains that have only one glycolipid instead of two glycolipid variants. 相似文献
1000.
Marco Taborda André Antunes Igor Tiago António Veríssimo M. Fernanda Nobre Milton S. da Costa 《Systematic and applied microbiology》2009
A halophilic, aerobic Gram-negative bacterium, designated strain CVS-6T, was isolated from a sea salt evaporation pond on the Island of Sal in the Cape Verde Archipelago. Phylogenetic analysis of the 16S rRNA gene sequence revealed a clear affiliation of the organism with members of the family Idiomarinaceae. Sequence similarities between CVS-6T and the type strains of the species of the genera Pseudidiomarina and Idiomarina ranged from 93.7% to 96.9%. The major isoprenoid quinone was ubiquinone 8 (Q-8). The major cellular fatty acids were 15:0 iso (21.8%), 17:0 iso (12.5%), 17:1 iso ω9c (10.7%), and 16:1 ω7c (10.6%). The DNA G+C content was 51.6 mol%. The species represented by strain CVS-6T could be distinguished from the species of the genera Pseudidiomarina and Idiomarina; however, it was not possible to distinguish both genera from each other using the phenotypic or chemotaxonomic characteristics examined. Consequently, we propose that the species classified in the genus Pseudidiomarina should be transferred to the genus Idiomarina. We also propose that, on the basis of physiological and biochemical characteristics, strain CVS-6T (=LMG 23123=CIP 108836) represents a new species which we name Idiomarina insulisalsae. 相似文献