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1.
Pegah Amiri Azar Shahpiri Mohammad Ali Asadollahi Fariborz Momenbeik Siavash Partow 《Biotechnology letters》2016,38(3):503-508
Objectives
To engineer the yeast Saccharomyces cerevisiae for the heterologous production of linalool.Results
Expression of linalool synthase gene from Lavandula angustifolia enabled heterologous production of linalool in S. cerevisiae. Downregulation of ERG9 gene, that encodes squalene synthase, by replacing its native promoter with the repressible MET3 promoter in the presence of methionine resulted in accumulation of 78 µg linalool l?1 in the culture medium. This was more than twice that produced by the control strain. The highest linalool titer was obtained by combined repression of ERG9 and overexpression of tHMG1. The yeast strain harboring both modifications produced 95 μg linalool l?1.Conclusions
Although overexpression of tHMG1 and downregulation of ERG9 enhanced linalool titers threefold in the engineered yeast strain, alleviating linalool toxicity is necessary for further improvement of linalool biosynthesis in yeast.2.
Objectives
To enhance the yield of 9α-hydroxy-4-androstene-3,17-dione (9-OHAD) from phytosterols, a phytosterol transport system was constructed in Mycobacterium sp. strain MS136.Results
9-OHAD can be produced via the controlled degradation of phytosterols by mycobacteria. This involves an active transport process that requires trans-membrane proteins and ATP. A phytosterol transport system from Mycobacterium tuberculosis H37Rv was constructed in Mycobacterium sp. strain MS136 by co-expression of an energy-related gene, mceG, and two integrated membrane protein genes, yrbE4A and yrbE4B. The resultant of the Mycobacterium sp. strain MS136-GAB gave 5.7 g 9-OHAD l?1, which was a 20% increase over 4.7 g l?1 by the wild-type strain. The yield of 9-OHAD was increased to 6.0 g l?1 by optimization of fermentation conditions, when 13 g phytosterols l?1 were fermented for 84 h in 30 ml biotransformation medium in shake flasks.Conclusions
Phytosterol transport system plays an active role in the uptake and transport of sterols, cloning of the system improved the mass transfer of phytosterols and increased the production of 9-OHAD.3.
4.
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.5.
Gianfranco Picone Francesco Savorani Alessia Trimigno Bruno Mezzetti Francesco Capozzi Søren Balling Engelsen 《Metabolomics : Official journal of the Metabolomic Society》2016,12(10):150
Introduction
The Deficiens Homologue 9-iaaM (DefH9-iaaM) gene is an ovule-specific auxin-synthesizing gene which is expressed specifically in placenta/ovules and promotes auxin-synthesis. It was introduced into the genome of two grape cultivars Thompson Seedless and Silcora and both transgenic cultivars had an increased number of berries per bunch.Objectives
This study investigates the down-stream metabolic changes of Silcora and Thompson seedless grape cultivars when genetically modified through the insertion of the DefH9-iaaM gene into their genome.Methods
The effects of the genetic modification upon the grape metabolome were evaluated through 1H-NMR and exploratory data analysis. Chemometric tools such as Interval Partial Least Squares regression and metabolite heatmaps were employed for scrutinizing the changes in the transgenic metabolome as compared to the wild type one.Results
The results show that the pleiotropic effect on the grape metabolome as a function of the gene modifications is relatively low, although the insertion of the transgene caused a decrement in malic acid and proline and an increment in p-coumaric acid content. In addition, the concentration of malic acid was successfully correlated with the number of inserted copies of transgene in the Silcora cultivar, proving that the increased production of berries, promoted by the inserted gene, is achieved at the expense of a decrement in malic acid concentration.Conclusion
NMR together with chemometrics is able to identify specific metabolites that were up- or down regulated in the genetically engineered plants allowing highlighting alterations in the down-stream metabolic pathways due to the up-stream genetic modifications.6.
Introduction
Cellulose microfibril is a major cell wall polymer that plays an important role in the growth and development of plants. The gene cellulose synthase A (CesA), encoding cellulose synthases, is involved in the synthesis of cellulose microfibrils. However, the regulatory mechanism of CesA gene expression is not well understood, especially during the early developmental stages.Objective
To identify factor(s) that regulate the expression of CesA genes and ultimately control seedling growth and development.Methods
The presence of cis-elements in the promoter region of the eight CesA genes identified in flax (Linum usitatissimum L. ‘Nike’) seedlings was verified, and three kinds of ethylene-responsive cis-elements were identified in the promoters. Therefore, the effect of ethylene on the expression of four selected CesA genes classified into Clades 1 and 6 after treatment with 10?4 and 10?3 M 1-aminocyclopropane-1-carboxylic acid (ACC) was examined in the hypocotyl of 4–6-day-old flax seedlings.Results
ACC-induced ethylene either up- or down-regulated the expression of the CesA genes depending on the clade to which these genes belonged, age of seedlings, part of the hypocotyl, and concentration of ACC.Conclusion
Ethylene might be one of the factors regulating the expression of CesA genes in flax seedlings.7.
Marie GB Hansen Mette Christoffersen Line R Thuesen Morten R Petersen Anders M Bojesen 《Acta veterinaria Scandinavica》2010,52(1):3
Background
Borrelia burgdorferi sensu lato and Anaplasma phagocytophilum are able to infect horses. However, the extend to which Danish horses are infected and seroconvert due to these two bacteria is unknown. The aim of the present study was to evaluate the seroprevalence of B. burgdorferi sensu lato and A. phagocytophilum in Danish horses.Methods
A total of 390 blood samples collected from all major regions of Denmark and with a geographical distribution corresponding to the density of the Danish horse population were analyzed. All samples were examined for the presence of antibodies against B. burgdorferi sensu lato and A. phagocytophilum by the use of the SNAP®4DX ® ELISA test.Results
Overall, 29.0% of the horses were seropositive for B. burgdorferi sensu lato whereas 22.3% were seropositive for A. phagocytophilum.Conclusions
Antibodies against B burgdorferi sensu lato and A. phagocytophilum are commonly found among Danish horses thus showing that Danish horses are frequently infected by these organisms.8.
Lili Wei Leixi Cao Yanyan Miao Shuju Wu Shumei Xu Ruisheng Wang Jun Du Aihua Liang Yuejun Fu 《Biotechnology letters》2017,39(8):1129-1139
9.
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.10.
Ye Mun Low Ivan Kok Seng Yap Kartini Abdul Jabar Mohd Yasim Md Yusof Chun Wie Chong Cindy Shuan Ju Teh 《Metabolomics : Official journal of the Metabolomic Society》2017,13(5):65
Introduction
Genotype and metabolomic variation are important for bacterial survival and adaptation to environmental changes.Objectives
In this study, we compared the relationship among Klebsiella pneumoniae strains based on their genotypic and metabolic profiles. In addition, we also evaluated the association of the relationship with beta-lactamase production.Methods
A total of 53 K. pneumoniae strains isolated in 2013–2014 from a tertiary teaching hospital in Malaysia were subjected to antimicrobial susceptibility testing (AST) via disk diffusion method and beta-lactamase production confirmation. The bacterial strains were also typed genotypically and metabolically via REP-PCR and 1H-NMR spectroscopy respectively. The concordance of the matrices derived based on genotypic and metabolic characterization was measured based on Spearman’s rank correlation.Results
Spearman’s correlation rank showed that there is a weak but significant negative correlation between the genetic fingerprints and metabolic profiles of K. pneumoniae. Specifically, K. pneumoniae strains were clustered into five major clusters based on REP-PCR where most of the carbapenem resistant K. pneumoniae (CRKP) strains made up the major cluster. In contrast, metabolic patterns of the three groups (i.e. CRKP, extended spectrum beta-lactamase producing K. pneumoniae (ESBL), susceptible) of K. pneumoniae were clearly differentiated on PLS-DA score plots derived from 1H-NMR spectroscopy.Conclusion
Overall, this study showed that metabolomic profiling using 1H-NMR spectroscopy is able to discriminate K. pneumoniae strains based on their beta-lactamase production status.11.
Background
Malaria Rapid Diagnostic Tests (RDTs) are widely used to diagnose malaria. The present study evaluated a new RDT, the Clearview® Malaria pLDH test targeting the pan-Plasmodium antigen lactate dehydrogenase (pLDH).Methods
The Clearview® Malaria pLDH test was evaluated on fresh samples obtained in returned international travellers using microscopy corrected by PCR as the reference method. Included samples were Plasmodium falciparum (139), Plasmodium vivax (22), Plasmodium ovale (20), Plasmodium malariae (7), and 102 negative.Results
Overall sensitivity for the detection of Plasmodium spp was 93.2%. For P. falciparum, the sensitivity was 98.6%; for P. vivax, P. ovale and P. malariae, overall sensitivities were 90.9%, 60.0% and 85.7% respectively. For P. falciparum and for P. vivax, the sensitivities increased to 100% at parasite densities above 100/μl. The specificity was 100%. The test was easily to perform and the result was stable for at least 1 hour.Conclusion
The Clearview® Malaria pLDH was efficient for the diagnosis of malaria. The test was very sensitive for P. falciparum and P. vivax detection. The sensitivities for P. ovale and P. malariae were better than other RDTs12.
Sheng Zhang Fang Wang Congli Fan Bo Tang Xueming Zhang Ziyi Li 《Biotechnology letters》2016,38(3):395-402
Objectives
We have examined dynamic changes of histone H3 lysine 9 following trimethylation (H3K9me3), the mRNA expression levels of SUV39H1 and SUV39H2 in bovine oocytes and the role in the development of in vitro fertilization (IVF) pre-implantation embryos.Results
There were strong H3K9me3 signals in germinal vesicle (GV) oocytes but no signals in MII oocytes. H3K9me3 signals were maintained during IVF pre-implantation embryo development. SUV39H1 and SUV39H2 showed significantly higher mRNA expression levels in GV oocytes than MII oocytes (P < 0.01). SUV39H1 showed high mRNA expression level in two-cell embryos, however, SUV39H2 showed high mRNA expression level in four-cell embryos. In other development stage, SUV39H1 and SUV39H2 showed low expression levels.Conclusion
Bovine IVF pre-implantation embryos maintain strong H3K9me3 signals and SUV39H1 and SUV39H2 are highly expressed at the early development stage of pre-implantation embryos.13.
Woo-Ri Kang Min-Ju Seo Jung-Ung An Kyung-Chul Shin Deok-Kun Oh 《Biotechnology letters》2016,38(5):817-823
Objective
To produce δ-decalactone from linoleic acid by one-pot reaction using linoleate 13-hydratase with supplementation with whole Yarrowia lipolytica cells.Results
Whole Y. lipolytica cells at 25 g l?1 produced1.9 g l?1 δ-decalactone from 7.5 g 13-hydroxy-9(Z)-octadecenoic acid l?1 at pH 7.5 and 30 °C for 21 h. Linoleate 13-hydratase from Lactobacillus acidophilus at 3.5 g l?1 with supplementation with 25 g Y. lipolytica cells l?1 in one pot at 3 h produced 1.9 g l?1 δ-decalactone from 10 g linoleic acid l?1 via 13-hydroxy-9(Z)-octadecenoic acid intermediate at pH 7.5 and 30°C after 18 h, with a molar conversion yield of 31 % and productivity of 106 mg l?1 h?1.Conclusion
To the best of our knowledge, this is the first production of δ-decalactone using unsaturated fatty acid.14.
Objectives
To characterize a novel feruloyl esterase from Escherichia coli BL21 DE3.Results
The gene encoding BioH was cloned and overexpressed in E. coli. The protein was purified and its catalytic activity was assessed. BioH exhibited feruloyl esterase activity toward a broad range of substrates, and the corresponding kinetic constants for the methyl ferulate, ethyl ferulate, and methyl p-coumarate substrates were: K m values of 0.48, 6.3, and 1.9 mM, respectively, and k cat /K m values of 9.3, 3.8, and 3.8 mM?1 s?1, respectively.Conclusions
Feruloyl esterase from E. coli was expressed for the first time. BioH was confirmed to be a feruloyl esterase.15.
Dagmara Głód 《Biotechnology letters》2017,39(5):767-773
Objective
To generate Candida antarctica lipase A (CAL-A) mutants with modified fatty acid selectivities and improved lipolytic activities using error-prone PCR (epPCR).Results
A Candida antarctica lipase A mutant was obtained in three rounds of epPCR. This mutant showed a 14 times higher ability to hydrolyze triacylglycerols containing conjugated linoleic acids, and was 12 and 14 times more selective towards cis-9, trans-11 and trans-10, cis-12 isomers respectively, compared to native lipase. Lipolytic activities towards fatty acid esters were markedly improved, in particular towards butyric, lauric, stearic and palmitic esters.Conclusion
Directed molecular evolution is an efficient method to generate lipases with desirable selectivity towards CLA isomers and improved lipolytic activities towards esters of fatty acids.16.
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.17.
Objectives
To trace the critical practicing, clinical and epidemiological risk factors in bacterial load and points of intervention in spread of community-acquired methicillin resistant Staphylococcus aureus (CA-MRSA) in healthy community.Study Design
2872 individuals with no prominent clinical features were enrolled and administered a pre-tested questionnaire prepared on the basis of outcome of a prior pilot study in same region. Swab samples from skin, throat and nasal nares were tested for MRSA and molecular identification was done to track the strains moving from hospital to community.Methods
Swab samples from skin, throat and nasal nares were tested for MRSA culture followed by molecular characterization of isolates and antimicrobial resistance pattern. Bacterial load was estimated to better understand the burden in different categories. Statistical analysis was done using SPSS 16.0 version.Results
History of prior infection (OR 3.9, 95% CI 1.363 – 5.793), habit of self remedy (OR 3.2, 95% CI 0.991 – 1.473) and incomplete treatment (OR 0.26, 95% CI 0.08 – 0.80) (P < 0.05 for each) were the predominant factors that contributed to spread of CA-MRSA. Increased drug resistance in CA-MRSA was observed for 4 different clones: SCCmec + IVa/PVL +, SCCmec + IVa/PVL ? and SCCmec + IVc/PVL +, SCCmec + IVc/PVL ?. Bacterial load was found significantly high in below poverty line dwellers and drug abusers (P < 0.05).Conclusion
We identified habit of self remedy, drug abusing and incomplete treatment as practicing risk factors where interventions can be made to manage the dissemination of CA-MRSA in rural population.18.
Hayley Whitfield Andrew M. Riley Soulla Diogenous Himali Y. Godage Barry V. L. Potter Charles A. Brearley 《Plant and Soil》2018,427(1-2):149-161
Background and aims
In many soils inositol hexakisphosphate in its various forms is as abundant as inorganic phosphate. The organismal and geochemical processes that exchange phosphate between inositol hexakisphosphate and other pools of soil phosphate are poorly defined, as are the organisms and enzymes involved. We rationalized that simple enzymic synthesis of inositol hexakisphosphate labeled with 32P would greatly enable study of transformation of soil inositol phosphates when combined with robust HPLC separations of different inositol phosphates.Methods
We employed the enzyme inositol pentakisphosphate 2-kinase, IP5 2-K, to transfer phosphate from [γ-32P]ATP to axial hydroxyl(s) of myo-, neo- and 1D-chiro-inositol phosphate substrates.Results
32P-labeled inositol phosphates were separated by anion exchange HPLC with phosphate eluents. Additional HPLC methods were developed to allow facile separation of myo-, neo-, 1D-chiro- and scyllo-inositol hexakisphosphate on acid gradients.Conclusions
We developed enzymic approaches that allow the synthesis of labeled myo-inositol 1,[32P]2,3,4,5,6-hexakisphosphate; neo-inositol 1,[32P]2,3,4,[32P]5,6–hexakisphosphate and 1D-chiro-inositol [32P]1,2,3,4,5,[32P]6-hexakisphosphate. Additionally, we describe HPLC separations of all inositol hexakisphosphates yet identified in soils, using a collection of soil inositol phosphates described in the seminal historic studies of Cosgrove, Tate and coworkers. Our study will enable others to perform radiotracer experiments to analyze fluxes of phosphate to/from inositol hexakisphosphates in different soils.19.
Objectives
To enhance succinic acid production in Corynebacterium glutamicum by increasing the supply of NADH and the rate of glucose consumption by decreasing H+-ATPase activity.Results
A mutant of C. glutamicum NC-3-1 with decreased H+-ATPase activity was constructed. This increased the rate of glycolysis and the supply of NADH. Fermentation of C. glutamicum NC-3-1 gave 39 % higher succinic acid production (113 and 81 g/l), a 29 % higher succinic acid yield (0.94 and 0.73 g succinic acid/g glucose) and decreased by-products formation compared to that of C. glutamicum NC-3 in 5 l bioreactor.Conclusion
The point mutation in C. glutamicum NC-3-1 increased the rate of glycolysis and resulted in higher succinic acid production, higher succinic acid yield and significantly decreased formation of by-products.20.