共查询到20条相似文献,搜索用时 515 毫秒
1.
Objectives
To characterize a novel ene-reductase from Meyerozyma guilliermondii and achieve the ene-reductase-mediated reduction of activated C=C bonds.Results
The gene encoding an ene-reductase was cloned from M. guilliermondii. Sequence homology analysis showed that MgER shared the maximal amino acid sequence identity of 57 % with OYE2.6 from Scheffersomyces stipitis. MgER showed the highest specific activity at 30 °C and pH 7 (100 mM sodium phosphate buffer), and excellent stereoselectivities were achieved for the reduction of (R)-carvone and ketoisophorone. Under the reaction conditions (30 °C and pH 7.0), 150 mM (R)-carvone could be completely converted to (2R,5R)-dihydrocarvone within 22 h employing purified MgER as catalyst, resulting in a yield of 98.9 % and an optical purity of >99 % d.e.Conclusion
MgER was characterized as a novel ene-reductase from yeast and showed great potential for the asymmetric reduction of activated C=C bonds of α,β-unsaturated compounds.2.
Objectives
To identify a novel nitrilase with S-selectivity toward mandelonitrile that can produce (S)-mandelic acid in one step.Results
A novel nitrilase PpL19 from Pseudomonas psychrotolerans L19 was discovered by genome mining. It showed S-selectivity with an enantiomeric excess of 52.7 % when used to hydrolyse (R, S)-mandelonitrile. No byproduct was observed. PpL19 was overexpressed in Escherichia coli BL21 (DE3) and formed inclusion bodies that were active toward mandelonitrile and stable across a broad range of temperature and pH. In addition, PpL19 hydrolysed nitriles with diverse structures; arylacetonitriles were the optimal substrates. Homology modelling and docking studies of both enantiomers of mandelonitrile in the active site of nitrilase PpL19 shed light on the enantioselectivity.Conclusions
A novel nitrilase PpL19 from P. psychrotolerans L19 was mined and distinguished from other nitrilases as it was expressed as an active inclusion body and showed S-selectivity toward mandelonitrile.3.
Objectives
To develop a versatile Trichoderma reesei (teleomorph Hypocrea jecorina) expression system for the high-purity production of heterologous proteins.Results
The versatile T. reesei expression system is based on xyn1 and xyn2 promoters, A824V transition in XYRI, and a bicomponent carbon source strategy. Red fluorescent protein gene rfp and alkaline endoglucanase EGV gene egv3 from Humicola insolens were used as reporter genes to test our versatile expression systemConclusions
The versatile T. reesei expression system can be applied to produce heterologous proteins with high purity and high yield.4.
Kai Zhang Huijuan Su Muhan Yang Jing Ge Guiyao Li Jun Yi Yang Wang 《Biotechnology letters》2017,39(6):905-909
Objectives
To establish a positive cloning system with a zero background for high-throughput DNA cloning purpose.Results
The cloning vector, pRI857, and the genomic-library construction vector, pRI857-BAC, were constructed based on the mechanism of expression of the thermo-sensitive cI857 repressor gene that can stringently repress the PR promoter and kanamycin resistance gene (PR-kan R ) at 30 °C, but have no effect on PR-kan R gene at 37 °C or at higher temperatures. When the pRI857 vectors were transformed into E. coli with or without a target foreign DNA fragment inserted at the BfrBI site of the cI857 gene, only colonies with the foreign DNA fragment survive. We extended this method to construct a pRI857-BAC vector for genomic library cloning which displays an efficiency of ~107 cfu per µg of genomic DNA, with no empty vectors detected.Conclusions
Cloning by indirect activation of resistance marker gene represents a novel DNA-capturing system, which can be widely applied for high-throughput DNA cloning.5.
Nicholas J. Bond Albert Koulman Julian L. Griffin Zoe Hall 《Metabolomics : Official journal of the Metabolomic Society》2017,13(11):128
Introduction
Mass spectrometry imaging (MSI) experiments result in complex multi-dimensional datasets, which require specialist data analysis tools.Objectives
We have developed massPix—an R package for analysing and interpreting data from MSI of lipids in tissue.Methods
massPix produces single ion images, performs multivariate statistics and provides putative lipid annotations based on accurate mass matching against generated lipid libraries.Results
Classification of tissue regions with high spectral similarly can be carried out by principal components analysis (PCA) or k-means clustering.Conclusion
massPix is an open-source tool for the analysis and statistical interpretation of MSI data, and is particularly useful for lipidomics applications.6.
Thijs Welle Anna T. Hoekstra Ineke A. J. J. M. Daemen Celia R. Berkers Matheus O. Costa 《Metabolomics : Official journal of the Metabolomic Society》2017,13(7):83
Introduction
Swine dysentery caused by Brachyspira hyodysenteriae is a production limiting disease in pig farming. Currently antimicrobial therapy is the only treatment and control method available.Objective
The aim of this study was to characterize the metabolic response of porcine colon explants to infection by B. hyodysenteriae.Methods
Porcine colon explants exposed to B. hyodysenteriae were analyzed for histopathological, metabolic and pro-inflammatory gene expression changes.Results
Significant epithelial necrosis, increased levels of l-citrulline and IL-1α were observed on explants infected with B. hyodysenteriae.Conclusions
The spirochete induces necrosis in vitro likely through an inflammatory process mediated by IL-1α and NO.7.
Matthias?Tisler Franziska?Wetzel Sabrina?Mantino Stanislav?Kremnyov Thomas?Thumberger Axel?Schweickert Martin?Blum Philipp?Vick
Background
Left-right (LR) organ asymmetries are a common feature of metazoan animals. In many cases, laterality is established by a conserved asymmetric Nodal signaling cascade during embryogenesis. In most vertebrates, asymmetric nodal induction results from a cilia-driven leftward fluid flow at the left-right organizer (LRO), a ciliated epithelium present during gastrula/neurula stages. Conservation of LRO and flow beyond the vertebrates has not been reported yet.Results
Here we study sea urchin embryos, which use nodal to establish larval LR asymmetry as well. Cilia were found in the archenteron of embryos undergoing gastrulation. Expression of foxj1 and dnah9 suggested that archenteron cilia were motile. Cilia were polarized to the posterior pole of cells, a prerequisite of directed flow. High-speed videography revealed rotating cilia in the archenteron slightly before asymmetric nodal induction. Removal of cilia through brief high salt treatments resulted in aberrant patterns of nodal expression. Our data demonstrate that cilia - like in vertebrates - are required for asymmetric nodal induction in sea urchin embryos.Conclusions
Based on these results we argue that the anterior archenteron represents a bona fide LRO and propose that cilia-based symmetry breakage is a synapomorphy of the deuterostomes.8.
Sayaka Okuzono Masataka Ishimura Shunsuke Kanno Motoshi Sonoda Noriyuki Kaku Yoshitomo Motomura Hisanori Nishio Utako Oba Masuo Hanada Jun-ichi Fukushi Michiyo Urata Dongchon Kang Hidetoshi Takada Shouichi Ohga 《Annals of clinical microbiology and antimicrobials》2018,17(1):31
Background
Streptococcus pyogenes is an uncommon pathogen of purpura fulminans, and the pathogenesis of S. pyogenes-purpura fulminans remains unclear because of paucity of cases. We reported a pediatric case of S. pyogenes-purpura fulminans with literature review of the disease.Case presentation
A 3-year-old boy showed limping, lethargy and acral gangrene within 24 h. A diagnosis of S. pyogenes-purpura fulminans was made for bacterial isolation from throat and peripheral blood. Intensive therapy led to a survival with amputation of the left distal metatarsal bone, and normal development. The isolated M12 carried no mutation of csrS/R or rgg. Thrombophilia or immunodeficiency was excluded.Discussion
Twelve-reported cases (9 pediatric and 3 elderly) of S. pyogenes-purpura fulminans started with shock and coagulopathy. Five patients age <?8 years had no underlying disease and survived. One youngest and two immunocompromised patients died.Conclusion
Streptococcus pyogenes-acute infectious purpura fulminans is a distinctive rare form of aggressive GAS infections.9.
Zhengling Liu Zengyan Wang Changhong Hao Yonghui Tian Jingjing Fu 《Reproductive biology and endocrinology : RB&E》2018,16(1):120
Background
Whether adiponectin (ADIPOQ) polymorphisms are associated with the risk of polycystic ovary syndrome (PCOS) remain controversial. Therefore, we performed this study to better explore correlations between ADIPOQ polymorphisms and PCOS risk.Methods
Literature retrieve was conducted in PubMed, Medline and Embase. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated.Results
Eighteen studies were enrolled for analyses. Pooled overall analyses showed that rs1501299 polymorphism was significantly associated with PCOS risk (recessive model: p?=?0.02, OR?=?0.77, 95%CI 0.62–0.95; allele model: p?=?0.001, OR?=?1.15, 95%CI 1.06–1.26). Further subgroup analyses according to ethnicity of participants revealed that rs1501299 and rs2241766 polymorphisms were both significantly correlated with PCOS risk in Caucasians. In addition, rs1501299 polymorphism was also significantly correlated with PCOS risk in East Asians.Conclusions
Our findings indicated that rs1501299 and rs2241766 polymorphisms might serve as genetic biomarkers of PCOS in certain ethnicities.10.
Objectives
To characterize the genes responsible for ethanol utilization in Pichia pastoris.Results
ADH3 (XM_002491337) and ADH (FN392323) genes were disrupted in P. pastoris. The ADH3 mutant strain, MK115 (Δadh3), lost its ability to grow on minimal ethanol media but produced ethanol in minimal glucose medium. ADH3p was responsible for 92 % of total Adh enzyme activity in glucose media. The double knockout strain MK117 (Δadh3Δadh) also produced ethanol. The Adh activities of X33 and MK116 (Δadh) strains were not different. Thus, the ADH gene does not play a role in ethanol metabolism.Conclusion
The PpADH3 is the only gene responsible for consumption of ethanol in P. pastoris.11.
Wenwen Zhang Zhaohui Chen Mengmeng Wu Zhong Shi Feng Zhu Guoqiang li Ting Ma 《Biotechnology letters》2016,38(6):991-997
Objective
To improve the production of welan gum and obtain a carotenoid-free strain while reducing the fermentation and post-treatment costs.Results
The vitreoscilla globin (vgb) gene combined with the β-galactosidase (lacZ) promoter was inserted into the phytoene synthase (crtB) gene region of the chromosome in Alcaligenes sp. ATCC31555. When the recombinant strain was grown in a 5 l fermentor, welan gum was produced at 24 ± 0.4 g l?1 compared to 21 g ± 0.4 g l?1 in the wild type. Furthermore, the carotenoid-free welan gum produced using Alcaligenes sp. ATCC31555 VHb strain was less expensive with improved properties.Conclusions
Alcaligenes sp. ATCC31555 VHb strain was a better neutral welan-producing strain with a higher production than the wild-type strain.12.
Objectives
To screen the phylogenetically-nearest members of Cellulosimicrobium cellulans for the production of cellulosome-like multienzyme complexes and extracellular β-xylosidase activity against 7-xylosyltaxanes and to get corresponding molecular insights.Results
Cellulosimicrobium (family Promicromonosporaceae) and all genera of the family Cellulomonadeceaec produced both cellulosome-like multienzyme complexes and extracellular β-xylosidase activity, while the other genera of the family Promicromonosporaceae did not. Multiple sequence alignments further indicated that hypothetic protein M768_06655 might be a possible key subunit.Conclusion
This is the first report that many actinobacteria species can produce cellulosome-like multienzyme complexes. The production of cellulosome-like complexes and the extracellular β-xylosidase activity against 7-xylosyltaxanes might be used to differentiate the genus Cellulosimicrobium from other genera of the family Promicromonosporaceae.13.
Chih-Yueh Liu Chang-Ching Weng Chih-Hsiang Lin Chiou-Ying Yang Kwok-Kong Tony Mong Yaw-Kuen Li 《Biotechnology letters》2017,39(3):407-413
Objectives
A Neissaria bacterial pilus sugar, bacillosamine, was synthesized and, for the first time, used as a probe to screen a single-chain variable fragment (scFv).Results
Four Neisseria, Neisseria gonorrhoeae, Neisseria meningitidis, Neisseria sicca and Neisseria subflava, and two negative controls, Streptococcus pneumoniae and Escherichia coli, were tested through ELISA, immunostaining and gold nanoparticle immunological assay. All results indicated that the selected scFv is feasible for the specific detection of Neisseria species via the recognition of bacillosamine.Conclusions
The recombinant scFv could detect Neisseria strains at 106 CFU/ml.14.
Xiaohong Chen Junjun Chen Yuanxing Zhang Ping Zhu Yong Deng Qin Liu 《Biotechnology letters》2016,38(6):959-967
Objective
To achieve secreted expression of the truncated capsid protein from porcine circovirus type 2 (PCV2) in Pichia pastoris.Results
A truncated cap gene (tcap) with a deleted N-terminal nuclear localization signal was optimized and synthesized. Effective secreted expression was achieved in P. pastoris GS115. The high-productive recombinant strain for tCap was grown in a 5 l bioreactor and the productivity of tCap in supernatant reached 250 μg/ml. Furthermore, serum antibody test demonstrated that adjuvant-assisting tCap induced a significant increase of specific PCV2-Cap antibody over time in mice and a similar antibody level in pigs compared with a commercial Cap-based subunit vaccine.Conclusion
This work establishes a secreted expression strategy in P. pastoris for the production of PCV2 Cap with superior bioactivity, and this strategy might provide potential uses in developing Cap-based subunit vaccine in the future.15.
Yibin Zhuang Jingjie Jiang Huiping Bi Hua Yin Shaowei Liu Tao Liu 《Biotechnology letters》2016,38(4):619-627
Objectives
To produce rosmarinic acid analogues in the recombinant Escherichia coli BLRA1, harboring a 4-coumarate: CoA ligase from Arabidopsis thaliana (At4CL) and a rosmarinic acid synthase from Coleus blumei (CbRAS).Results
Incubation of the recombinant E. coli strain BLRA1 with exogenously supplied phenyllactic acid (PL) and analogues as acceptor substrates, and coumaric acid and analogues as donor substrates led to production of 18 compounds, including 13 unnatural RA analogues.Conclusion
This work demonstrates the viability of synthesizing a broad range of rosmarinic acid analogues in E. coli, and sheds new light on the substrate specificity of CbRAS.16.
Elaheh Sajadi Valiollah Babaipour Ali Asghar Deldar Bagher Yakhchali Seyed Safa-Ali Fatemi 《Biotechnology letters》2017,39(9):1395-1401
Objectives
To evaluate the crystallinity index of the cellulose produced by Escherichia coli Nissle 1917 after heterologous expression of the cellulose synthase subunit D (bcsD) gene of Gluconacetobacter xylinus BPR2001.Results
The bcsD gene of G. xylinus BPR2001 was expressed in E. coli and its protein product was visualized using SDS-PAGE. FTIR analysis showed that the crystallinity index of the cellulose produced by the recombinants was 0.84, which is 17% more than that of the wild type strain. The increased crystallinity index was also confirmed by X-ray diffraction analysis. The cellulose content was not changed significantly after over-expressing the bcsD.Conclusion
The bcsD gene can improve the crystalline structure of the bacterial cellulose but there is not any significant difference between the amounts of cellulose produced by the recombinant and wild type E. coli Nissle 1917.17.
Boubaker J Bhouri W Sghaier MB Bouhlel I Skandrani I Ghedira K Chekir-Ghedira L 《Cancer cell international》2011,11(1):37
Background
In this report the phytochemical profile of Nitraria. Retusa (N. Retusa) leaf extracts were identified and their ability to induce apoptosis in human chronic myelogenous erythroleukaemia (K562) was evaluated.Methods
Apoptosis of the human chronic myelogenous erythroleukaemia (K562) was evidenced by investigating DNA fragmentation, PARP cleavage and caspases 3 and 8 inducing activities, in the presence of N. retusa extracts.Results
Our study revealed that the tested extracts from N. Retusa contain many useful bioactive compounds. They induced in a time-dependent manner the apoptosis the tested cancerous our cell line. This result was confirmed by ladder DNA fragmentation profile and PARP cleavage, as well as a release in caspase-3 and caspase-8 level.Conclusion
Our results indicate that the tested compounds have a significant antiproliferative effect which may be due to their involvement in the induction of the extrinsic apoptosic pathway.18.
Cicheng Zhang Xiaoyan Li Huawu Wu Pei Wang Yang Wang Xiuchen Wu Wei Li Yongmei Huang 《Plant and Soil》2017,419(1-2):169-187
Background and aims
Understanding the responses of different plant species to changes in available water sources is critical for accurately modeling and predicting species dynamics. Our study aimed to explore whether there were differences in water-use strategies between the two coexisting shrubs (Reaumuria soongorica and Nitraria sphaerocarpa) in response to different amounts of summer precipitation.Methods
We conducted 3 years of field observations at three sites along an aridity gradient from the middle to lower reaches of the Heihe River basin, northwestern China. Stable oxygen composition (δ18O) in plant xylem water, soil water and groundwater were analyzed concurrently with ecophysiological measurements at monthly intervals during the growing seasons.Results
Water source for coexisting R. soongorica and N. sphaerocarpa did not differ at the sites with high precipitation, but significantly differed in more arid locations. The N. sphaerocarpa was more sensitive to summer precipitation than R. soongorica in terms of predawn water potential, stomatal conductance and foliage carbon-isotope discrimination.Conclusions
The plants relying on groundwater maintained consistent water use strategies, but not plants that took up precipitation-derived water. We also found that the difference in water source uptake between the coexisting species was more apparent in more arid locations.19.
Jinxiang Zhu Qiaoyun Zhu Ruiqing Gong Qin Xu Menghao Cai Tianyi Jiang Xiangshan Zhou Mian Zhou Yuanxing Zhang 《Biotechnology letters》2018,40(9-10):1365-1376
Objective
Around one-fourth of the Komagataella phaffii genes encode hypothetical proteins with unknown functions. However, lack of powerful tools for genetic screening in K. phaffii significantly limits the functional analysis of these unknown genes. Transposon mutagenesis has been utilized as an insertional mutagenesis tool in many other organisms and would be extremely valuable if it could be applied in K. phaffii.Results
In this study, we investigated in K. phaffii the transposition activity and efficiency of piggyBac (PB) transposon, a DNA transposon from the cabbage looper moth Trichoplusia ni through the integrated-plasmid system. We also designed a binary-plasmid system which could generate stable mutants. Finally we evaluated the quality of this mutagenesis system by a simple screening for functional genes involved in K. phaffii carbon catabolite repression.Conclusions
Our results demonstrate that PB-mediated mutagenesis could be a feasible and useful tool for functional gene screening in K. phaffii.20.
Thais Freitas da Silva Renata Estebanez Vollú Joana Montezano Marques Joana Falcão Salles Lucy Seldin 《Plant and Soil》2017,414(1-2):69-79