Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 142
Filter
1.
Chinese Journal of Biotechnology ; (12): 1298-1311, 2021.
Article in Chinese | WPRIM | ID: wpr-878632

ABSTRACT

As a class of multifunctional biocatalysts, halohydrin dehalogenases are of great interest for the synthesis of chiral β-substituted alcohols and epoxides. There are less than 40 halohydrin dehalogenases with relatively clear catalytic functions, and most of them do not meet the requirements of scientific research and practical applications. Therefore, it is of great significance to excavate and identify more halohydrin dehalogenases. In the present study, a putative halohydrin dehalogenase (HHDH-Ra) from Rhodospirillaceae bacterium was expressed and its enzymatic properties were investigated. The HHDH-Ra gene was cloned into the expression host Escherichia coli BL21(DE3) and the target protein was shown to be soluble. Substrate specificity studies showed that HHDH-Ra possesses excellent specificity for 1,3-dichloro-2-propanol (1,3-DCP) and ethyl-4-chloro-3-hydroxybutyrate (CHBE). The optimum pH and temperature for HHDH-Ra with 1,3-DCP as the reaction substrate were 8.0 and 30 °C, respectively. HHDH-Ra was stable at pH 6.0-8.0 and maintained about 70% of its original activity after 100 h of treatment. The thermal stability results revealed that HHDH-Ra has a half-life of 60 h at 30 °C and 40 °C. When the temperature is increased to 50 °C, the enzyme still has a half-life of 20 h, which is much higher than that of the reported enzymes. To sum up, the novel halohydrin dehalogenase from Rhodospirillaceae bacterium possesses good temperature and pH stability as well as catalytic activity, and shows the potential to be used in the synthesis of chemical and pharmaceutical intermediates.


Subject(s)
Escherichia coli/metabolism , Hydrolases/metabolism , Rhodospirillaceae , Substrate Specificity
2.
Chinese Journal of Biotechnology ; (12): 604-614, 2021.
Article in Chinese | WPRIM | ID: wpr-878585

ABSTRACT

Proton-pumping rhodopsin (PPR) is a simple photosystem widely distributed in nature. By binding to retinal, PPR can transfer protons from the cytoplasmic to the extracellular side of the membrane under illumination, creating a proton motive force (PMF) to synthesize ATP. The conversion of light into chemical energy by introducing rhodopsin into nonphotosynthetic engineered strains could contribute to promoting growth, increasing production and improving cell tolerance of microbial hosts. Gloeorhodopsin (GR) is a PPR from Gloeobacter violaceus PCC 7421. We expressed GR heterologously in Escherichia coli and verified its functional activity. GR could properly function as a light-driven proton pump and its absorption maximum was at 539 nm. We observed that GR was mainly located on the cell membrane and no inclusion body could be found. After increasing expression level by ribosome binding site optimization, intracellular ATP increased, suggesting that GR could supply additional energy to heterologous hosts under given conditions.


Subject(s)
Cyanobacteria/metabolism , Escherichia coli/metabolism , Proton Pumps , Rhodopsin/metabolism , Rhodopsins, Microbial/metabolism
3.
Chinese Journal of Biotechnology ; (12): 4395-4405, 2021.
Article in Chinese | WPRIM | ID: wpr-921515

ABSTRACT

To investigate the enzyme properties of the black sesame polyphenol oxidase (BsPPO), a synthesized Bsppo gene was cloned into the vector pMAL-c5x and expressed in E. coli. Subsequently, the MBP fusion label in the recombinant protein was removed by protease digestion after affinity purification. The synthesized Bsppo gene contained 1 752 bp which encodes 585 amino acids with a deduced molecular weight of 65.3 kDa. Transformation of the recombinant vector into E. coli BL21(DE3) resulted in soluble expression of the fusion protein MBP-BsPPO. The enzymatic properties of the recombinant BsPPO was investigated after MBP fusion tag excision followed by affinity purification. The results demonstrated that the optimal temperature and pH for BsPPO was 25°C and 4.0, respectively. BsPPO exhibited a good stability under low temperature and acidic environment. Low-intensity short-term light exposure increased the activity of BsPPO. Cu²⁺ could improve the activity of BsPPO while Zn²⁺ and Ca²⁺ showed the opposite effect. BsPPO could catalyze the oxidation of monophenols, diphenols, and triphenols, and exhibited good catalytic activity on l-tyrosine and vanillic acid. Moreover, BsPPO exhibited high catalytic activity on black sesame metabolites, including 2-methoxy cinnamic acid, indole-3-carboxylic acid and phloretin. These results may serve as a basis for further characterization of BsPPO.


Subject(s)
Catechol Oxidase/genetics , Cloning, Molecular , Escherichia coli/metabolism , Recombinant Proteins/genetics , Sesamum/genetics
4.
Chinese Journal of Biotechnology ; (12): 4266-4276, 2021.
Article in Chinese | WPRIM | ID: wpr-921504

ABSTRACT

Dopamine is the precursor of a variety of natural antioxidant compounds. In the body, dopamine acts as a neurotransmitter that regulates a variety of physiological functions of the central nervous system. Thus, dopamine is used for the clinical treatment of various types of shock. Dopamine could be produced by engineered microbes, but with low efficiency. In this study, DOPA decarboxylase gene from Sus scrofa (Ssddc) was cloned into plasmids with different copy numbers, and transformed into a previously developed L-DOPA producing strain Escherichia coli T004. The resulted strain was capable of producing dopamine from glucose directly. To further improve the production of dopamine, a sequence-based homology alignment mining (SHAM) strategy was applied to screen more efficient DOPA decarboxylases, and five DOPA decarboxylase genes were selected from 100 candidates. In shake-flask fermentation, the DOPA decarboxylase gene from Homo sapiens (Hsddc) showed the highest dopamine production (3.33 g/L), while the DOPA decarboxylase gene from Drosophila Melanogaster (Dmddc) showed the least residual L-DOPA concentration (0.02 g/L). In 5 L fed-batch fermentations, production of dopamine by the two engineered strains reached 13.3 g/L and 16.2 g/L, respectively. The residual concentrations of L-DOPA were 0.45 g/L and 0.23 g/L, respectively. Finally, the Ssddc and Dmddc genes were integrated into the genome of E. coli T004 to obtain genetically stable dopamine-producing strains. In 5 L fed-batch fermentation, 17.7 g/L of dopamine was produced, which records the highest titer reported to date.


Subject(s)
Animals , Dopa Decarboxylase/genetics , Dopamine/biosynthesis , Drosophila melanogaster/genetics , Escherichia coli/metabolism , Humans , Metabolic Engineering
5.
Chinese Journal of Biotechnology ; (12): 3300-3309, 2021.
Article in Chinese | WPRIM | ID: wpr-921426

ABSTRACT

In Gram-negative bacteria, lipopolysaccharide transport (Lpt) protein LptA and LptC form a complex to transport LPS from the inner membrane (IM) to the outer membrane (OM). Blocking the interaction between LptA and LptC will lead to the defect of OM and cell death. Therefore, Lpt protein interaction could be used as a target to screen new drugs for killing Gram-negative bacteria. Here we used biolayer interferometry (BLI) assay to detect the interaction between LptA and LptC, with the aim to develop a method for screening the LptA/LptC interaction blockers in vitro. Firstly, LptC and LptA with or without signal peptide (LptAfull or LptAno signal) were expressed in E. coli BL21(DE3). The purified proteins were then labeled with biotin and the super streptavidin (SSA) biosensor was blocked with diluent. The biotin labeled protein sample was mixed with the sensor, and then the binding of the protein with a series of diluted non biotinylated protein was detected. At the same time, non-biotinylated protein was used as a control. The binding of biotinylated protein to a small molecule IMB-881 and the blocking of interaction were also detected by the same method. In the blank control, the biosensor without biotinylated protein was used to detect the serially diluted samples. The signal response constant was calculated by using steady analysis. The results showed that biotinylated LptC had a good binding activity with LptAfull and LptAno signal with KD value 2.9e⁻⁷±7.9e⁻⁸ and 6.0e⁻⁷±2.8e⁻⁸, respectively; biotinylated LptAno signal had a good binding activity with LptC, with a KD value of 9.6e⁻⁷±7.2e⁻⁸. All binding curves showed obvious fast binding and fast dissociation morphology. The small molecule compound IMB-881 can bind to LptA to block the interaction between LptA and LptC, but has no binding activity with LptC. In summary, we developed a method for detecting the LptA/LptC interaction based on the BLI technology, and confirmed that this method can be used to evaluate the blocking activity of small molecule blockers, providing a new approach for the screening of LptA/LptC interaction blockers.


Subject(s)
Carrier Proteins , Escherichia coli/metabolism , Escherichia coli Proteins/metabolism , Interferometry , Membrane Proteins/metabolism
6.
Electron. j. biotechnol ; 46: 8-13, jul. 2020. tab, graf
Article in English | LILACS | ID: biblio-1223212

ABSTRACT

BACKGROUND: Poly-3-hydroxybutyrate (PHB) can be efficiently produced in recombinant Escherichia coli by the overexpression of an operon (NphaCAB) encoding PHB synthetase. Strain improvement is considered to be one of critical factors to lower the production cost of PHB in recombinant system. In this study, one of key regulators that affect the cell growth and PHB content was confirmed and analyzed. RESULT: S17-3, a mutant E. coli strain derived from S17-1, was found to be able to achieve high cell density when expressing NphaCAB with the plasmid pBhya-CAB. Whole genome sequencing of S17-3 revealed genetic alternations on the upstream regions of csrA, encoding a global regulator cross-talking between stress response, catabolite repression and other metabolic activities. Deletion of csrA or expression of mutant csrA resulted in improved cell density and PHB content. CONCLUSION: The impact of gene deletion of csrA was determined, dysfunction of the regulators improved the cell density of recombinant E. coli and PHB production, however, the detail mechanism needs to be further clarified.


Subject(s)
Escherichia coli/metabolism , Hydroxybutyrates/metabolism , Repressor Proteins/genetics , Biopolymers/genetics , Recombinant Proteins , RNA-Binding Proteins/genetics , Gene Deletion , Escherichia coli Proteins/genetics , Escherichia coli/genetics , Metabolic Engineering , Ligases/metabolism
7.
Electron. j. biotechnol ; 39: 67-73, may. 2019. graf, tab
Article in English | LILACS | ID: biblio-1052039

ABSTRACT

BACKGROUND: The supplementation of betaine, an osmoprotective compatible solute, in the cultivation media has been widely used to protect bacterial cells. To explore the effects of betaine addition on industrial fermentation, Escherichia coli THRD, an L-threonine producer, was used to examine the production of L-threonine with betaine supplementation and the underlying mechanism through which betaine functions was investigated. RESULTS: Betaine supplementation in the medium of E. coli THRD significantly improved L-threonine fermentation parameters. The transcription of zwf and corresponding enzyme activity of glucose-6-phosphate dehydrogenase were significantly promoted by betaine addition, which contributed to an enhanced expression of zwf that provided more nicotinamide adenine dinucleotide phosphate (NADPH) for L-threonine synthesis. In addition, as a result of the betaine addition, the betaine-stimulated expression of enhanced green fluorescent protein (eGFP) under the zwf promoter within a plasmid-based cassette proved to be a transcription-level response of zwf. Finally, the promoter of the phosphoenolpyruvate carboxylase gene ppc in THRD was replaced with that of zwf, while L-threonine fermentation of the new strain was promoted by betaine addition. Conclusions: We reveal a novel mode of betaine that facilitates the microbial production of useful compounds. Betaine supplementation upregulates the expression of zwf and increases the NADPH synthesis, which may be beneficial for the cell growth and thereby promote the production of L-threonine. This finding might be useful for the production of NADPH-dependent amino acids and derivatives in E. coli THRD or other E. coli strains.


Subject(s)
Threonine/metabolism , Betaine/metabolism , Escherichia coli/metabolism , Osmosis , Pentose Phosphate Pathway , Reverse Transcriptase Polymerase Chain Reaction , Escherichia coli/enzymology , Fermentation , Glucosephosphate Dehydrogenase/metabolism , NADP
8.
Electron. j. biotechnol ; 38: 19-26, Mar. 2019. ilus, tab
Article in English | LILACS | ID: biblio-1051542

ABSTRACT

Caffeic acid (CA; 3,4-dihydroxycinnamic acid) is an aromatic compound obtained by the phenylpropanoid pathway. This natural product has antioxidant, antitumor, antiviral, and anti-inflammatory activities. It is also a precursor of CA phenethyl ester (CAPE), a compound with potential as an antidiabetic and liver-protective agent. CA can be found at low concentrations in plant tissues, and hence, its purification is difficult and expensive. Knowledge regarding the pathways, enzymes, and genes involved in CA biosynthesis has paved the way for enabling the design and construction of microbial strains with the capacity of synthesizing this metabolite. In this review, metabolic engineering strategies for the generation of Escherichia coli strains for the biotechnological production of CA are presented and discussed.


Subject(s)
Caffeic Acids/metabolism , Escherichia coli/metabolism , Metabolic Engineering/methods , Biological Products , Biotechnology , Coumaric Acids
9.
J. appl. oral sci ; 27: e20180641, 2019. tab, graf
Article in English | LILACS, BBO | ID: biblio-1012519

ABSTRACT

Abstract Objectives: Infection, inflammation and bone resorption are closely related events in apical periodontitis development. Therefore, we sought to investigate the role of cyclooxygenase (COX) in osteoclastogenesis and bone metabolism signaling in periapical bone tissue after bacterial lipopolysaccharide (LPS) inoculation into root canals. Methodology: Seventy two C57BL/6 mice had the root canals of the first molars inoculated with a solution containing LPS from E. coli (1.0 mg/mL) and received selective (celecoxib) or non-selective (indomethacin) COX-2 inhibitor. After 7, 14, 21 and 28 days the animals were euthanized and the tissues removed for total RNA extraction. Evaluation of gene expression was performed by qRT-PCR. Statistical analysis was performed using analysis of variance (ANOVA) followed by post-tests (α=0.05). Results: LPS induced expression of mRNA for COX-2 (Ptgs2) and PGE2 receptors (Ptger1, Ptger3 and Ptger4), indicating that cyclooxygenase is involved in periapical response to LPS. A signaling that favours bone resorption was observed because Tnfsf11 (RANKL), Vegfa, Ctsk, Mmp9, Cd36, Icam, Vcam1, Nfkb1 and Sox9 were upregulated in response to LPS. Indomethacin and celecoxib differentially modulated expression of osteoclastogenic and other bone metabolism genes: celecoxib downregulated Igf1r, Ctsk, Mmp9, Cd36, Icam1, Nfkb1, Smad3, Sox9, Csf3, Vcam1 and Itga3 whereas indomethacin inhibited Tgfbr1, Igf1r, Ctsk, Mmp9, Sox9, Cd36 and Icam1. Conclusions: We demonstrated that gene expression for COX-2 and PGE2 receptors was upregulated after LPS inoculation into the root canals. Additionally, early administration of indomethacin and celecoxib (NSAIDs) inhibited osteoclastogenic signaling. The relevance of the cyclooxygenase pathway in apical periodontitis was shown by a wide modulation in the expression of genes involved in both bone catabolism and anabolism.


Subject(s)
Animals , Male , Osteogenesis/physiology , Periapical Tissue/drug effects , Periapical Tissue/metabolism , Lipopolysaccharides/pharmacology , Cyclooxygenase Inhibitors/pharmacology , Prostaglandin-Endoperoxide Synthases/physiology , Dental Pulp Cavity/metabolism , Osteogenesis/drug effects , Time Factors , Bone Resorption/metabolism , Gene Expression , Up-Regulation , Anti-Inflammatory Agents, Non-Steroidal/pharmacology , Indomethacin/pharmacology , Lipopolysaccharides/analysis , Prostaglandin-Endoperoxide Synthases/analysis , Prostaglandin-Endoperoxide Synthases/drug effects , Receptors, Prostaglandin E/analysis , Reverse Transcriptase Polymerase Chain Reaction , Escherichia coli/metabolism , Cyclooxygenase 2/analysis , Celecoxib/pharmacology , Mice, Inbred C57BL
10.
Braz. j. microbiol ; 49(4): 848-855, Oct.-Dec. 2018. tab, graf
Article in English | LILACS | ID: biblio-974300

ABSTRACT

ABSTRACT We studied the role of Thermus thermophilus Recombinase A (RecA) in enhancing the PCR signals of DNA viruses such as Hepatitis B virus (HBV). The RecA gene of a thermophilic eubacterial strain, T. thermophilus, was cloned and hyperexpressed in Escherichia coli. The recombinant RecA protein was purified using a single heat treatment step without the use of any chromatography steps, and the purified protein (>95%) was found to be active. The purified RecA could enhance the polymerase chain reaction (PCR) signals of HBV and improve the detection limit of the HBV diagnosis by real time PCR. The yield of recombinant RecA was ∼35 mg/L, the highest yield reported for a recombinant RecA to date. RecA can be successfully employed to enhance detection sensitivity for the diagnosis of DNA viruses such as HBV, and this methodology could be particularly useful for clinical samples with HBV viral loads of less than 10 IU/mL, which is interesting and novel.


Subject(s)
Bacterial Proteins/genetics , Hepatitis B virus/isolation & purification , Polymerase Chain Reaction/methods , Thermus thermophilus/enzymology , Cloning, Molecular , Recombinases/genetics , Bacterial Proteins/isolation & purification , Bacterial Proteins/metabolism , Gene Expression , Hepatitis B virus/genetics , Polymerase Chain Reaction/instrumentation , Thermus thermophilus/genetics , Recombinases/isolation & purification , Recombinases/metabolism , Escherichia coli/genetics , Escherichia coli/metabolism
11.
Electron. j. biotechnol ; 35: 18-24, sept. 2018. ilus, tab, graf
Article in English | LILACS | ID: biblio-1047727

ABSTRACT

Background: Lactate dehydrogenase (LDH) is an enzyme of glycolytic pathway, ubiquitously found in living organisms. Increased glycolysis and LDH activity are associated with many pathologic conditions including inflammation and cancer, thereby making the enzyme a suitable drug target. Studies on conserved structural and functional domains of LDH from various species reveal novel inhibitory molecules. Our study describes Escherichia coli production and characterization of a moderately thermostable LDH (LDH-GT) from Geobacillus thermodenitrificans DSM-465. An in silico 3D model of recombinant enzyme and molecular docking with a set of potential inhibitors are also described. Results: The recombinant enzyme was overexpressed in E. coli and purified to electrophoretic homogeneity. The molecular weight of the enzyme determined by MALDI-TOF was 34,798.96 Da. It exhibited maximum activity at 65°C and pH 7.5 with a KM value for pyruvate as 45 µM. LDH-GT and human LDH-A have only 35.6% identity in the amino acid sequence. On the contrary, comparison by in silico structural alignment reveals that LDH-GT monomer has approximately 80% identity to that of truncated LDH-A. The amino acids "GEHGD" as well as His179 and His193 in the active site are conserved. Docking studies have shown the binding free energy changes of potential inhibitors with LDH-A and LDH-GT ranging from −407.11 to −127.31 kJ mol−1 . Conclusions: By highlighting the conserved structural and functional domains of LDH from two entirely different species, this study has graded potential inhibitory molecules on the basis of their binding affinities so that they can be applied for in vivo anticancer studies


Subject(s)
Geobacillus/enzymology , L-Lactate Dehydrogenase/metabolism , Computer Simulation , Enzyme Stability , Polymerase Chain Reaction , Cloning, Molecular , Escherichia coli/metabolism , Molecular Docking Simulation , Glycolysis , L-Lactate Dehydrogenase/genetics
12.
Braz. j. microbiol ; 49(3): 569-574, July-Sept. 2018. tab, graf
Article in English | LILACS | ID: biblio-951794

ABSTRACT

Abstract Multidrug-resistant microorganisms are of great concern to public health. Genetic mobile elements, such as plasmids, are among the most relevant mechanisms by which bacteria achieve this resistance. We obtained an Escherichia coli strain CM6, isolated from cattle presenting severe diarrheic symptoms in the State of Querétaro, Mexico. It was found to contain a 70 kb plasmid (pMEX01) with a high similarity to the pHK01-like plasmids that were previously identified and described in Hong Kong. Analysis of the pMEX01 sequence revealed the presence of a blaCTX-M-14 gene, which is responsible for conferring resistance to multiple β-lactam antibiotics. Several genes putatively involved in the conjugative transfer were also identified on the plasmid. The strain CM6 is of high epidemiological concern because it not only displays resistance to multiple β-lactam antibiotics but also to other kinds of antibiotics.


Subject(s)
Animals , Cattle , Plasmids/genetics , Cattle Diseases/microbiology , Drug Resistance, Bacterial , beta-Lactams/pharmacology , Escherichia coli/drug effects , Escherichia coli/genetics , Escherichia coli Infections/veterinary , Anti-Bacterial Agents/pharmacology , Plasmids/metabolism , beta-Lactamases/genetics , beta-Lactamases/metabolism , Microbial Sensitivity Tests , Escherichia coli Proteins/genetics , Escherichia coli Proteins/metabolism , Escherichia coli/metabolism , Escherichia coli Infections/microbiology , Mexico
13.
Braz. j. microbiol ; 49(3): 662-667, July-Sept. 2018. tab, graf
Article in English | LILACS | ID: biblio-951808

ABSTRACT

Abstract The effect of the intracellular microenvironment in the presence of an oxygen vector during expression of a fusion protein in Escherichia coli was studied. Three organic solutions at different concentration were chosen as oxygen vectors for fumarase expression. The addition of n-dodecane did not induce a significant change in the expression of fumarase, while the activity of fumarase increased significantly to 124% at 2.5% n-dodecane added after 9 h induction. The concentration of ATP increased sharply during the first 6 h of induction, to a value 7600% higher than that in the absence of an oxygen-vector. NAD/NADH and NADP/NADPH ratios were positively correlated with fumarase activity. n-Dodecane can be used to increase the concentration of ATP and change the energy metabolic pathway, providing sufficient energy for fumarase folding.


Subject(s)
Oxygen/metabolism , Gene Expression , Alkanes/metabolism , Escherichia coli/genetics , Fumarate Hydratase/metabolism , Oxygen/chemistry , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Recombinant Proteins/chemistry , Protein Folding , Alkanes/chemistry , Escherichia coli/metabolism , Fumarate Hydratase/genetics , Fumarate Hydratase/chemistry , NADP/metabolism , NADP/chemistry
14.
Electron. j. biotechnol ; 34: 29-36, july. 2018. ilus, tab, graf
Article in English | LILACS | ID: biblio-1045993

ABSTRACT

Background: Recombinant DNA technology enables us to produce proteins with desired properties and insubstantial amount for industrial applications. Endo-1, 4-ß-glucanases (Egl) is one of the major enzyme involved in degradation of cellulose, an important component of plant cell wall. The present study was aimed at enhancing the production of endo-1, 4-ß-glucanases (Egl) of Bacillus halodurans in Escherichia coli. Results: A putative Egl gene of Bacillus Halodurans was expressed in E. coli by cloning in pET 22b (+). On induction with isopropyl-b-D-1-thiogalactopyranoside, the enzyme expression reached upto ~20% of the cell protein producing 29.2 mg/liter culture. An increase in cell density to 12 in auto-inducing LB medium (absorbance at 600 nm) enhanced ß-glucanase production up to 5.4 fold. The molecular mass of the enzyme was determined to be 39 KDa, which is nearly the same as the calculated value. Protein sequence was analyzed by CDD, Pfam, I TASSER, COACH, PROCHECK Servers and putative amino acids involved in the formation of catalytic, substrate and metal binding domains were identified. Phylogenetic analysis of the ß-glucanases of B. halodurans was performed and position of Egl among other members of the genus Bacillus producing endo-glucanases was determined. Temperature and pH optima of the enzyme were found to be 60°C and 8.0, respectively, under the assay conditions. Conclusion: Production of endo-1, 4 ß-glucanase enzymes from B. halodurans increased several folds when cloned in pET vector and expressed in E. coli. To our knowledge, this is the first report of high-level expression and characterization of an endo-1, 4 ß-glucanases from B. halodurans.


Subject(s)
Bacillus/enzymology , Cellulases/biosynthesis , Temperature , Enzyme Stability , Gene Expression , Cell Wall/enzymology , Polymerase Chain Reaction , Cloning, Molecular , Cellulases/isolation & purification , Cellulases/metabolism , Escherichia coli/metabolism , Plant Cells/enzymology , Hydrogen-Ion Concentration , Hydrolysis
15.
Braz. j. microbiol ; 49(2): 414-421, Apr.-June 2018. tab, graf
Article in English | LILACS | ID: biblio-889234

ABSTRACT

Abstract Agricultural crops suffer many diseases, including fungal and bacterial infections, causing significant yield losses. The identification and characterisation of pathogenesis-related protein genes, such as chitinases, can lead to reduction in pathogen growth, thereby increasing tolerance against fungal pathogens. In the present study, the chitinase I gene was isolated from the genomic DNA of Barley (Hordeum vulgare L.) cultivar, Haider-93. The isolated DNA was used as template for the amplification of the ∼935 bp full-length chitinase I gene. Based on the sequence of the amplified gene fragment, class I barley chitinase shares 93% amino acid sequence homology with class II wheat chitinase. Interestingly, barley class I chitinase and class II chitinase do not share sequence homology. Furthermore, the amplified fragment was expressed in Escherichia coli Rosetta strain under the control of T7 promoter in pET 30a vector. Recombinant chitinase protein of 35 kDa exhibited highest expression at 0.5 mM concentration of IPTG. Expressed recombinant protein of 35 kDa was purified to homogeneity with affinity chromatography. Following purification, a Western blot assay for recombinant chitinase protein measuring 35 kDa was developed with His-tag specific antibodies. The purified recombinant chitinase protein was demonstrated to inhibit significantly the important phytopathogenic fungi Alternaria solani, Fusarium spp, Rhizoctonia solani and Verticillium dahliae compared to the control at concentrations of 80 µg and 200 µg.


Subject(s)
Antifungal Agents/pharmacology , Chitinases/pharmacology , Hordeum/enzymology , Recombinant Proteins/metabolism , Antifungal Agents/chemistry , Antifungal Agents/isolation & purification , Blotting, Western , Chitinases/chemistry , Chitinases/genetics , Chitinases/isolation & purification , Chromatography, Affinity , Escherichia coli/genetics , Escherichia coli/metabolism , Gene Expression , Hordeum/genetics , Molecular Weight , Recombinant Proteins/chemistry , Recombinant Proteins/genetics , Recombinant Proteins/isolation & purification , Sequence Homology, Amino Acid
16.
Electron. j. biotechnol ; 33: 11-16, May. 2018. ilus, tab, graf
Article in English | LILACS | ID: biblio-1022822

ABSTRACT

Background: The plant secondary metabolite pinosylvin is a polyphenol from the stilbene family, which have positive effects on human health. Biotechnological production is an attractive alternative for obtaining this stilbene. In Escherichia coli, malonyl-CoA is the precursor for both stilbene and fatty acid syntheses. In this study, with the aim of increasing pinosylvin production, we evaluated a novel approach that is based on reducing the expression of the gene fabI, which encodes the enzyme enoyl-acyl carrier protein reductase that is involved in fatty acid synthesis. Results: A recombineering method was employed to eliminate the chromosomal -35 promoter sequence and the upstream region of the gene fabI in E. coli strain W3110. Analysis, employing RT-qPCR, showed that such modification caused a 60% reduction in the fabI transcript level in the mutant strain W3110Δ-35fabI::Cm compared to the wild type W3110. Synthetic genes encoding a mutant version of 4-coumaroyl-CoA ligase from Streptomyces coelicolor A3 with improved catalytic activity employing cinnamic acid as substrate and a stilbene synthase from Vitis vinifera were cloned to generate the plasmid pTrc-Sc4CL(M)-VvSTS. The production performance of strains W3110Δ-35fabI::Cm/pTrc-Sc4CL(M)-VvSTS and W3110/pTrc-Sc4CL(M)- VvSTS was determined in shake flask cultures with Luria-Bertani medium supplemented with 10 g/L glycerol and 3 mM cinnamic acid. Under these conditions, the strain W3110Δ-35fabI::Cm/pTrc-Sc4CL(M)-VvSTS produced 52.67 mg/L pinosylvin, a level 1.5-fold higher than that observed with W3110/pTrc-Sc4CL(M)-VvSTS. Conclusion: A reduction in the transcript level of fabI caused by the elimination of the -35 and upstream promoter sequences is a successful strategy to improve pinosylvin production in E. coli.


Subject(s)
Stilbenes/metabolism , Escherichia coli/metabolism , Enoyl-(Acyl-Carrier-Protein) Reductase (NADH)/genetics , Biological Products , Coenzyme A Ligases , Fatty Acids , Metabolic Engineering
17.
Electron. j. biotechnol ; 33: 29-35, May. 2018. tab, graf, ilus
Article in English | LILACS | ID: biblio-1022834

ABSTRACT

Background: P64k is a Neisseria meningitidis high molecular weight protein present in meningococcal vaccine preparations. The lpdA gene, which encodes for this protein, was cloned in Escherichia coli and the P64k recombinant protein was expressed in E. coli K12 GC366 cells under the control of a tryptophan promoter. P64k was expressed as an intracellular soluble protein about 28% of the total cellular protein. Several scale-up criteria of fermentation processes were studied to obtain the recombinant P64k protein at the pilot production scale. Results: The best operational conditions at a larger scale production of P64k recombinant protein were studied and compared using the four following criteria: Constant Reynold's number (Re constant), Constant impeller tip speed (n di constant), Constant power consumption per unit liquid volume (P/V constant) and Constant volumetric oxygen transfer coefficients (KLa/k constant). The highest production of the recombinant protein was achieved based on the constant KLa/k scale-up fermentation criterion, calculating the aeration rate (Q) and the impeller agitation speed (n) by iterative process, keeping constant the KLa/k value from bench scale. The P64k protein total production at the 50 l culture scale was 546 mg l -1 in comparison with the 284 mg l -1 obtained at 1.5 l bench scale. Conclusions: The methodology described herein, for the KLa/k scale-up fermentation criterion, allowed us to obtain the P64k protein at 50 l scale. A fermentation process for the production of P64k protein from N. meningitidis was established, a protein to be used in future vaccine formulations in humans.


Subject(s)
Bacterial Outer Membrane Proteins/biosynthesis , Recombinant Proteins/biosynthesis , Escherichia coli/metabolism , Neisseria meningitidis/metabolism , Tryptophan , Meningococcal Vaccines , Fermentation , Molecular Weight
18.
Electron. j. biotechnol ; 32: 1-5, Mar. 2018. ilus
Article in English | LILACS | ID: biblio-1022489

ABSTRACT

Background: TRF2 (telomeric repeat binding factor 2) is an essential component of the telomere-binding protein complex shelterin. TRF2 induces the formation of a special structure of telomeric DNA and counteracts activation of DNA damage-response pathways telomeres. TRF2 has a poorly characterized linker region (udTRF2) between its homodimerization and DNA-binding domains. Some lines of evidence have shown that this region could be involved in TRF2 interaction with nuclear lamina. Results: In this study, the fragment of the TERF2 gene encoding udTRF2 domain of telomere-binding protein TRF2 was produced by PCR and cloned into the pET32a vector. The resulting plasmid pET32a-udTRF2 was used for the expression of the recombinant udTRF2 in E. coli RosettaBlue (DE3). The protein was isolated and purified using ammonium sulfate precipitation followed by ion-exchange chromatography. The purified recombinant protein udTRF2 was injected into guinea pigs to generate polyclonal antibodies. The ability of anti-udTRF2 antibodies to bind endogenous TRF2 in human skin fibroblasts was tested by western blotting and immunofluorescent staining. Conclusions: In this study, the recombinant protein udTRF2 and antibodies to it were generated. Both protein and antibodies will provide a useful tool for investigation of the functions of the udTRF2 domain and its role in the interaction between TRF2 and nuclear lamina.


Subject(s)
Animals , Guinea Pigs , Telomeric Repeat Binding Protein 2/metabolism , Antibodies/metabolism , Plasmids , Recombinant Proteins/metabolism , Immunohistochemistry , Blotting, Western , Chromosomes , Cloning, Molecular , Nuclear Lamina , Telomeric Repeat Binding Protein 2/genetics , Immunoprecipitation , DNA-Binding Proteins/metabolism , Escherichia coli/metabolism , Antibodies/isolation & purification , Antibody Formation , Nucleoproteins
19.
Braz. J. Pharm. Sci. (Online) ; 54(4): e17724, 2018. tab, graf, ilus
Article in English | LILACS | ID: biblio-1001563

ABSTRACT

As there are a lot of antibacterial and anti-fungal resistant pathogens, researchers attempt to substitute antimicrobial drugs with various medical plants and novel nanoparticles. The present study was conducted to characterize antimicrobial activities of Euphorbia prostrata and Pelargonium graveolens extract alone and in combination with Mn-Ni@Fe3O4-NPs & Mn: Fe (OH)3-NPs on the DNA cleavage of E. coli and also Bacillus subtilis, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Aspergillus oryzae, and Candida albicans. The effects of antimicrobial activities on above scenarios were evaluated using disc diffusion, MIC, MBC, and E. coli DNA electrophoresis methods. The results showed that the effects of antibacterial assay values of Euphorbia prostrata & Mn: Fe(OH)3 was 21.00 mm for E. coli and while it was 19.5 mm for Euphorbia prostrata & Mn-Ni@Fe3O4 against Pseudomonas aeruginosa at a concentration of 100mg/mL. The highest level of DNA cleavage was seen in mixed of Euphorbia prostrata & Mn: Fe(OH)3 nanoparticles. In conclusion, the combination of Euphorbia prostrata and Pelargonium graveolens extracts with nanostructures showed synergic effects on eliminating the bacteria via DNA destruction and others mechanisms. Moreover, the synergistic effect of nanoparticles with plant extracts seems to bring about new choices for the treatment of infectious diseases


Subject(s)
Plant Extracts/analysis , Euphorbia prostata/adverse effects , Pelargonium/adverse effects , Nanoparticles/analysis , Candida albicans/metabolism , Escherichia coli/metabolism , Anti-Infective Agents/pharmacology
20.
Electron. j. biotechnol ; 30: 64-70, nov. 2017. ilus, graf, tab
Article in English | LILACS | ID: biblio-1021461

ABSTRACT

Background: The development of a potential single culture that can co-produce hydrogen and ethanol is beneficial for industrial application. Strain improvement via molecular approach was proposed on hydrogen and ethanol co-producing bacterium, Escherichia coli SS1. Thus, the effect of additional copy of native hydrogenase gene hybC on hydrogen and ethanol co-production by E. coli SS1 was investigated. Results: Both E. coli SS1 and the recombinant hybC were subjected to fermentation using 10 g/L of glycerol at initial pH 7.5. Recombinant hybC had about 2-fold higher cell growth, 5.2-fold higher glycerol consumption rate and 3-fold higher ethanol productivity in comparison to wild-type SS1. Nevertheless, wild-type SS1 reported hydrogen yield of 0.57 mol/mol glycerol and ethanol yield of 0.88 mol/mol glycerol, which were 4- and 1.4-fold higher in comparison to recombinant hybC. Glucose fermentation was also conducted for comparison study. The performance of wild-type SS1 and recombinant hybC showed relatively similar results during glucose fermentation. Additional copy of hybC gene could manipulate the glycerol metabolic pathway of E. coli SS1 under slightly alkaline condition. Conclusions: HybC could improve glycerol consumption rate and ethanol productivity of E. coli despite lower hydrogen and ethanol yields. Higher glycerol consumption rate of recombinant hybC could be an advantage for bioconversion of glycerol into biofuels. This study could serve as a useful guidance for dissecting the role of hydrogenase in glycerol metabolism and future development of effective strain for biofuels production.


Subject(s)
Ethanol/metabolism , Escherichia coli/metabolism , Hydrogen/metabolism , Hydrogenase/metabolism , Recombination, Genetic , Biodegradation, Environmental , Culture Media , Escherichia coli/enzymology , Alkalinization , Fermentation , Glucose/metabolism , Glycerol/metabolism , Hydrogenase/genetics
SELECTION OF CITATIONS
SEARCH DETAIL