scholarly journals Molecular and Biochemical Characterization of Salt-Tolerant Trehalose-6-Phosphate Hydrolases Identified by Screening and Sequencing Salt-Tolerant Clones From the Metagenomic Library of the Gastrointestinal Tract

2020 ◽  
Vol 11 ◽  
Author(s):  
Yanxia Yang ◽  
Yunjuan Yang ◽  
Qin Fan ◽  
Zunxi Huang ◽  
Junjun Li ◽  
...  
Keyword(s):  
Gastrointestinal Tract ◽  
Biochemical Characterization ◽  
Metagenomic Library ◽  
Salt Tolerant ◽  
Tolerant Clones

scholarly journals Biochemical Characterization of a New β-Agarase from Cellulophaga Algicola

2019 ◽  
Vol 20 (9) ◽  
pp. 2143 ◽  
Author(s):  
Han ◽  
Zhang ◽  
Yang
Keyword(s):  
Structural Model ◽  
Biochemical Characterization ◽  
Maximum Activity ◽  
Optimal Temperature ◽  
Salt Tolerant ◽  
Wide Ph Range ◽  
Specific Activities ◽  
Ph Range ◽  
Layer Chromatography

Cellulophaga algicola DSM 14237, isolated from the Eastern Antarctic coastal zone, was found to be able to hydrolyze several types of polysaccharide materials. In this study, a predicted β-agarase (CaAga1) from C. algicola was heterologously expressed in Escherichia coli. The purified recombinant CaAga1 showed specific activities of 29.39, 20.20, 14.12, and 8.99 U/mg toward agarose, pure agar, and crude agars from Gracilaria lemaneiformis and Porphyra haitanensis, respectively. CaAga1 exhibited an optimal temperature and pH of 40 oC and 7, respectively. CaAga1 was stable over a wide pH range from 4 to 11. The recombinant enzyme showed an unusual thermostability, that is, it was stable at temperature below or equal to 40oC and around 70 oC, but was thermolabile at about 50 oC. With the agarose as the substrate, the Km and Vmax values for CaAga1 were 1.19 mg/mL and 36.21 U/mg, respectively. The reducing reagent (dithiothreitol) enhanced the activity of CaAga1 by more than one fold. In addition, CaAga1 was salt-tolerant given that it retained approximately 70% of the maximum activity in the presence of 2 M NaCl. The thin layer chromatography results indicated that CaAga1 is an endo-type β-agarase and efficiently hydrolyzed agarose into neoagarotetraose (NA4) and neoagarohexaose (NA6). A structural model of CaAga1 in complex with neoagarooctaose (NA8) was built by homology modeling and explained the hydrolysis pattern of CaAga1.

scholarly journals Molecular and Biochemical Characterization of a Salt Tolerant α-Amylase Producing Isolate NH-25

2018 ◽  
Vol 14 ◽  
pp. 180-185
Author(s):  
Mahnaz Ahmad ◽  
Raheela Rahmat Zohra ◽  
Shah Ali Ul Qader ◽  
Keyword(s):  
Biochemical Characterization ◽  
Salt Tolerant

Identification and characterization of a novel salt-tolerant esterase from a Tibetan glacier metagenomic library

2015 ◽  
Vol 31 (4) ◽  
pp. 890-899 ◽  
Author(s):  
Concetta De Santi ◽  
Luca Ambrosino ◽  
Pietro Tedesco ◽  
Donatella de Pascale ◽  
Lei Zhai ◽  
...  
Keyword(s):  
Metagenomic Library ◽  
Salt Tolerant ◽  
Identification And Characterization

scholarly journals Biochemical Characterization of a Novel Monospecific Endo-β-1,4-Glucanase Belonging to GH Family 5 From a Rhizosphere Metagenomic Library

2019 ◽  
Vol 10 ◽  
Author(s):  
Anna Wierzbicka-Woś ◽  
Ruth Henneberger ◽  
Ramón Alberto Batista-García ◽  
Liliana Martínez-Ávila ◽  
Stephen A. Jackson ◽  
...  
Keyword(s):  
Biochemical Characterization ◽  
Metagenomic Library

Isolation and biochemical characterization of two lipases from a metagenomic library of China Holstein cow rumen

2009 ◽  
Vol 385 (4) ◽  
pp. 605-611 ◽  
Author(s):  
Kailang Liu ◽  
Jiaqi Wang ◽  
Dengpan Bu ◽  
Shengguo Zhao ◽  
Chris McSweeney ◽  
...  
Keyword(s):  
Biochemical Characterization ◽  
Metagenomic Library ◽  
Holstein Cow

scholarly journals Functional screening of a Caatinga goat (Capra hircus) rumen metagenomic library reveals a novel GH3 β-xylosidase

PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0245118
Author(s):  
Betulia de Morais Souto ◽  
Ana Carolina Bitencourt de Araújo ◽  
Pedro Ricardo Vieira Hamann ◽  
Andrêssa de Rezende Bastos ◽  
Isabel de Souza Cunha ◽  
...  
Keyword(s):  
Substrate Specificity ◽  
Biochemical Characterization ◽  
Plant Biomass ◽  
Enzyme Stability ◽  
Metagenomic Library ◽  
Capra Hircus ◽  
Functional Screening ◽  
Multiple Substrate ◽  
Goat Rumen

Functional screening of metagenomic libraries is an effective approach for identification of novel enzymes. A Caatinga biome goat rumen metagenomic library was screened using esculin as a substrate, and a gene from an unknown bacterium encoding a novel GH3 enzyme, BGL11, was identified. None of the BGL11 closely related genes have been previously characterized. Recombinant BGL11 was obtained and kinetically characterized. Substrate specificity of the purified protein was assessed using seven synthetic aryl substrates. Activity towards nitrophenyl-β-D-glucopyranoside (pNPG), 4-nitrophenyl-β-D-xylopyranoside (pNPX) and 4-nitrophenyl-β-D-cellobioside (pNPC) suggested that BGL11 is a multifunctional enzyme with β-glucosidase, β-xylosidase, and cellobiohydrolase activities. However, further testing with five natural substrates revealed that, although BGL11 has multiple substrate specificity, it is most active towards xylobiose. Thus, in its native goat rumen environment, BGL11 most likely functions as an extracellular β-xylosidase acting on hemicellulose. Biochemical characterization of BGL11 showed an optimal pH of 5.6, and an optimal temperature of 50°C. Enzyme stability, an important parameter for industrial application, was also investigated. At 40°C purified BGL11 remained active for more than 15 hours without reduction in activity, and at 50°C, after 7 hours of incubation, BGL11 remained 60% active. The enzyme kinetic parameters of Km and Vmax using xylobiose were determined to be 3.88 mM and 38.53 μmol.min-1.mg-1, respectively, and the Kcat was 57.79 s-1. In contrast to BLG11, most β-xylosidases kinetically studied belong to the GH43 family and have been characterized only using synthetic substrates. In industry, β-xylosidases can be used for plant biomass deconstruction, and the released sugars can be fermented into valuable bio-products, ranging from the biofuel ethanol to the sugar substitute xylitol.

Identification and Characterization of a Novel Carboxylesterase EstQ7 from a Soil Metagenomic Library

2021 ◽  
Author(s):  
Zhenzhen Yan ◽  
Liping Ding ◽  
Dandan Zou ◽  
Luyao Wang ◽  
Yuzhi Tan ◽  
...  
Keyword(s):  
Biochemical Characterization ◽  
Metagenomic Library ◽  
Catalytic Triad ◽  
Recombinant Enzyme ◽  
Fatty Acid Esters ◽  
Dimensional Structure ◽  
Sequence Alignments ◽  
Acyltransferase Activity ◽  
Lipolytic Enzymes

Abstract A novel lipolytic gene, estq7, was identified from a fosmid metagenomic library. The recombinant enzyme EstQ7 consists of 370 amino acids with an anticipated molecular mass of 42 kDa. Multiple sequence alignments showed that EstQ7 contained a pentapeptide motif GHSMG, and a putative catalytic triad Ser174–Asp306–His344. Interestingly, EstQ7 was found to have very little similarity to the characterized lipolytic enzymes. Phylogenetic analysis revealed that EstQ7 may be a member of a novel family of lipolytic enzymes. Biochemical characterization of the recombinant enzyme revealed that it constitutes a slightly alkalophilic, moderate thermophilic and highly active carboxylesterase against short chain fatty acid esters with optimum temperature 50 ℃ and pH 8.2. The Km and kcat values toward p-nitrophenyl acetate were determined to be 0.17 mM and 1910 S-1, respectively. Moreover, EstQ7 was demonstrated to have acyltransferase activity by GC-MS analysis. Homology modeling of the three-dimensional structure of this new enzyme showed that it exhibits a typical α/β hydrolase fold, and the catalytic triad residues are spatially close. Molecular docking reveled the interactions between the enzyme and the ligand. The high levels of lipolytic activity of EstQ7, combined with its moderate thermophilic property, and acyltransferase activity, render this novel enzyme a promising candidate biocatalyst for food, pharmaceutical and biotechnological applications.

Plant Pathology Diagnosed by X-Ray Microanalysis

1987 ◽  
Vol 45 ◽  
pp. 974-975
Author(s):  
J. H. Resau ◽  
N. Howell ◽  
S. H. Chang
Keyword(s):  
Electron Microscopy ◽  
Plant Pathology ◽  
Biochemical Characterization ◽  
Nutrient Deficiency ◽  
Green Leaf ◽  
Parasitic Infestation ◽  
X Ray

Spinach grown in Texas developed “yellow spotting” on the peripheral portions of the leaves. The exact cause of the discoloration could not be determined as there was no evidence of viral or parasitic infestation of the plants and biochemical characterization of the plants did not indicate any significant differences between the yellow and green leaf portions of the spinach. The present study was undertaken using electron microscopy (EM) to determine if a micro-nutrient deficiency was the cause for the discoloration.Green leaf spinach was collected from the field and sent by express mail to the EM laboratory. The yellow and equivalent green portions of the leaves were isolated and dried in a Denton evaporator at 10-5 Torr for 24 hrs. The leaf specimens were then examined using a JEOL 100 CX analytical microscope. TEM specimens were prepared according to the methods of Trump et al.

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