scholarly journals Characterization and Phylogenetic Analysis of a Novel GH43 β-Xylosidase From Neocallimastix californiae

2021 ◽  
Vol 2 ◽  
Author(s):  
Marcus Stabel ◽  
Julia Hagemeister ◽  
Zacharias Heck ◽  
Habibu Aliyu ◽  
Katrin Ochsenreither
Keyword(s):  
Phylogenetic Analysis ◽  
Hydrolytic Enzymes ◽  
Lignocellulosic Materials ◽  
Anaerobic Fungi ◽  
Temperature Optimum ◽  
Ph Optimum ◽  
Highly Active ◽  
Beechwood Xylan ◽  
Hemicellulose Degradation ◽  
Huge Variety

Degradation of lignocellulosic materials to release fermentable mono- and disaccharides is a decisive step toward a sustainable bio-based economy, thereby increasing the demand of robust and highly active lignocellulolytic enzymes. Anaerobic fungi of the phylum Neocallimastigomycota are potent biomass degraders harboring a huge variety of such enzymes. Compared to cellulose, hemicellulose degradation has received much less attention; therefore, the focus of this study has been the enzymatic xylan degradation of anaerobic fungi as these organisms produce some of the most effective known hydrolytic enzymes. We report the heterologous expression of a GH43 xylosidase, Xyl43Nc, and a GH11 endoxylanase, X11Nc, from the anaerobic fungus Neocallimastix californiae in Escherichia coli. The enzymes were identified by screening of the putative proteome. Xyl43Nc was highly active against 4-Nitrophenol-xylopyranosides with a Km of 0.72 mM, a kcat of 29.28 s−1, a temperature optimum of 32°C and a pH optimum of 6. When combined, Xyl43Nc and X11Nc released xylose from beechwood xylan and arabinoxylan from wheat. Phylogenetic analysis revealed that Xyl43Nc shares common ancestry with enzymes from Spirochaetes and groups separately from Ascomycete sequences in our phylogeny, highlighting the importance of horizontal gene transfer in the evolution of the anaerobic fungi.

scholarly journals Functional Expression and Characterization of Trichome-Specific (-)-Limonene Synthase and (+)-α-Pinene Synthase from Cannabis sativa

2007 ◽  
Vol 2 (3) ◽  
pp. 1934578X0700200 ◽  
Author(s):  
Nils Günnewich ◽  
Jonathan E. Page ◽  
Tobias G. Köllner ◽  
Jörg Degenhardt ◽  
Toni M. Kutchan
Keyword(s):  
Phylogenetic Analysis ◽  
Natural Products ◽  
Cannabis Sativa ◽  
Functional Expression ◽  
Temperature Optimum ◽  
Ph Optimum ◽  
Limonene Synthase ◽  
Monoterpene Synthases

Two recombinant, stereospecific monoterpene synthases, a (-)-limonene synthase (CsTPS1) and a (+)-α-pinene synthase (CsTPS2), encoded by Cannabis sativa L. cv. ‘Skunk’ trichome mRNA, have been isolated and characterized. Recombinant CsTPS1 showed a Km value of 6.8 μM, a Vmax of 1.1 × 10−4 μmol/min and Vmax/Km of 0.016; the pH optimum was determined at pH 6.5, and a temperature optimum at 40°C. Recombinant CsTPS2 showed a Km value of 10.5 μM, a Vmax of 2.2 × 10−4 μmol/min and Vmax/Km of 0.021; the pH optimum was determined at pH 7.0, and a temperature optimum at 30°C. Phylogenetic analysis showed that both CsTPSs group within the angiosperms and belong to the Tpsb subgroup of monoterpene synthases. The enzymatic products (-)-limonene and (+)-α-pinene were detected as natural products in C. sativa trichomes.

Biochemical studies on the production of neuraminidase by environmental isolates of Vibrio cholerae non-O1 from Bulgaria

2011 ◽  
Vol 57 (7) ◽  
pp. 606-610 ◽  
Author(s):  
Rumyana Eneva ◽  
Stephan Engibarov ◽  
Tanya Strateva ◽  
Radoslav Abrashev ◽  
Ignat Abrashev
Keyword(s):  
Vibrio Cholerae ◽  
Pathogenic Bacteria ◽  
Environmental Isolates ◽  
Anaerobic Conditions ◽  
Temperature Optimum ◽  
Ph Optimum ◽  
Cholera Vibrio ◽  
Key Factor ◽  
Aeration Conditions ◽  
The One

Neuraminidase is a key factor in the infectious process of many viruses and pathogenic bacteria. The neuraminidase enzyme secreted by the etiological agent of cholera — Vibrio cholerae О1 — is well studied in contrast with the one produced by non-O1/non-O139 V. cholerae. Environmental non-O1/non-O139 V. cholerae isolates from Bulgaria were screened for production of neuraminidase. The presence of the neuraminidase gene nanH was detected in 18.5% of the strains. Тhe strain showing highest activity (30 U/mL), V. cholerae non-O1/13, was used to investigate the enzyme production in several media and at different aeration conditions. The highest production of extracellular neuraminidase was observed under microaerophilic conditions, which is possibly related to its role in the infection of intestine epithelium, where the oxygen content is low. On the other hand, this is another advantage of the microbe in such microaerophilic environments as sediments and lake mud. The highest production of intracellular neuraminidase was observed at anaerobic conditions. The ratio of extracellular to intracellular neuraminidase production in V. cholerae was investigated. The temperature optimum of the enzyme was determined to be 50 °C and the pH optimum to be 5.6–5.8.

Biosynthesis of the Diguanosine Nucleotides. I. Purification and Properties of an Enzyme from Yolk Platelets of Brine Shrimp Embryos

1974 ◽  
Vol 52 (3) ◽  
pp. 231-240 ◽  
Author(s):  
A. H. Warner ◽  
P. C. Beers ◽  
F. L. Huang
Keyword(s):  
Molecular Weight ◽  
Brine Shrimp ◽  
Artemia Salina ◽  
Temperature Optimum ◽  
Small Molecular Weight ◽  
Ph Optimum ◽  
Optimal Activity ◽  
Purification And Properties

An enzyme that catalyzes the synthesis of P1P4-diguanosine 5′-tetraphosphate (Gp4G) has been isolated and purified from yolk platelets of encysted embryos of the brine shrimp, Artemia salina. The enzyme GTP:GTP guanylyltransferase (Gp4G synthetase) utilizes GTP as substrate, has a pH optimum of 5.9–6.0, a temperature optimum of 40–42 °C, and requires Mg2+ and dithiothreitol for optimal activity. The synthesis of Gp4G is inhibited markedly by pyrophosphate, whereas orthophosphate has no effect on the reaction. In the presence of GDP the enzyme also catalyzes the synthesis of P1,P3-diguanosine 5′-triphosphate (Gp3G), but the rate of synthesis is low compared with Gp4G synthesis and dependent upon other small molecular weight components of yolk platelets.

Temperature-induced alanine oxidation in a psychrotrophic Pseudomonas

1975 ◽  
Vol 21 (12) ◽  
pp. 2028-2033
Author(s):  
Prince K. Zachariah ◽  
John Liston
Keyword(s):  
Heat Treatment ◽  
Enzyme Synthesis ◽  
Optimum Temperature ◽  
Temperature Optimum ◽  
Ph Optimum ◽  
Sephadex Column ◽  
Oxidase System ◽  
Psychrotrophic Bacteria ◽  
Induction Of Enzymes ◽  
Elution Fraction

A psychrotrophic pseudomonad isolated from iced fish oxidized alanine at temperatures close to 0 °C and grew over the range 0 °C–35 °C. The rate of oxidation of alanine, measured manometrically, by cells grown at 2 °C was lower than that of cells grown at 22 °C. However, the consumption of oxygen after heat treatment at 35 °C for 35 min was reduced considerably by 2 °C grown cells. Alanine oxidase activity was tested in an extract from cells grown at 2 °C and 22 °C with alanine as the sole carbon, nitrogen, and energy source. Cells grown at 2 °C produced an alanine oxidase with a temperature optimum of 35 °C and pH optimum of 8, which lost about 80% activity by heat treatment at 40 °C for 30 min. There was no change in activity after dialysis at pH 7, 8, or 9. Extracts from cells grown at 22 °C contained an alanine oxidase system with an optimum temperature of 45 °C, a pH optimum above 8, and only about 30% reduction of activity after heat treatment. This enzyme activity was concentrated in the 0.5 M elution fraction from a Sephadex column, and dialysis reduced the activity at pH 7 and 8. Mesophilic enzyme synthesis apparently started around a growth temperature of 10 °C.The crude alanine oxidase systems of Pseudomonas aeruginosa derived from cells grown at 13 °C and 37 °C had a common optimum temperature of 45 °C. These data suggest that one mechanism of psychrophilic growth by psychrotrophic bacteria may be the induction of enzymes with low optimum temperatures in response to low temperature conditions.

Cellulase production by Acetivibrio cellulolyticus

1980 ◽  
Vol 26 (7) ◽  
pp. 760-765 ◽  
Author(s):  
J. N. Saddler ◽  
A. W. Khan
Keyword(s):  
Sewage Sludge ◽  
Cellulose Degradation ◽  
Cellulase Production ◽  
Cellulolytic Enzymes ◽  
Exponential Growth Phase ◽  
Cellulose Powder ◽  
Temperature Optimum ◽  
Ph Optimum ◽  
Culture Supernate ◽  
Cellulose Concentration

Acetivibrio cellulolyticus, an isolate from an established sewage sludge culture, degraded cellulose powder, Avicel cellulose, and cellobiose. The organism showed maximum cellulose degradation in a medium containing 10 g/L of cellulose and it could also degrade cellulose in media containing up to 75 g/L of cellulose. During the exponential growth phase, large quantities of cellulolytic enzymes were found extracellularly whereas cellobiase activity was cell associated. The crude culture supernate contained endo- and exo-glucanase activities with a pH optimum at 5.0 and a temperature optimum at 50 °C. Maximum cellulase activities were detected in 2- to 3-day-old cultures grown on 1 g/L of cellulose. Cellulose concentration above 10 g/L caused the adsorption of these enzymes to the substrate and consequently lowered their detection in the supernate. The activities at 50 °C for endoglucanase, exoglucanase, and filter paper degrading ability, expressed as micrograms of glucose equivalents released per minute per milligram of protein culture supernate, were 510, 135, and 40 respectively.

STUDIES ON SOLUBILIZED ADENYLATE KINASE FROM MITOCHONDRIA

1966 ◽  
Vol 44 (11) ◽  
pp. 1469-1475 ◽  
Author(s):  
Marjorie A. Brewster ◽  
Ezzat S. Younathan
Keyword(s):  
Activation Energy ◽  
Rat Liver ◽  
Adenylate Kinase ◽  
Divalent Cations ◽  
Metabolic Function ◽  
Kcal Mole ◽  
Temperature Optimum ◽  
Ph Optimum ◽  
Sensitive Method

Adenylate kinase from mitochondria of rat liver was made soluble by sonication. The enzyme had a pH optimum of 8.0, temperature optimum of 30°, and activation energy of 12.2 kcal/mole. It was activated by several divalent cations in the following order of efficiency: Mg++ > Co++ > Mn++ > Ca++, with an optimal Mg++: ADP ratio of 1. The apparent Km value (ADP as substrate) was found to be 1.3 mM at pH 7.4 and 30°. The activity was sensitive to phloretin and mildly activated by aurovertin. Oligomycin, 2,4-dinitrophenol, p-chloromercuribenzoate, alloxan, and phlorizin had no effect on the activity. The metabolic function and a comparison of the properties of this solubilized mitochondrial adenylate kinase with those of similar preparations from other sources are discussed in the light of these findings. During this study, a sensitive method adaptable for a large number of assays of adenylate kinase was developed, and is described in detail.

scholarly journals Reclassification of Trichlorobacter thiogenes as Geobacter thiogenes comb. nov.

2007 ◽  
Vol 57 (3) ◽  
pp. 463-466 ◽  
Author(s):  
Kelly P. Nevin ◽  
Dawn E. Holmes ◽  
Trevor L. Woodard ◽  
Sean F. Covalla ◽  
Derek R. Lovley
Keyword(s):  
Type Strain ◽  
Original Description ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Phylogenetic Position ◽  
Temperature Optimum ◽  
Ph Optimum ◽  
Donor And Acceptor ◽  
The Family ◽  
Electron Donor And Acceptor

Reclassification of the species Trichlorobacter thiogenes as Geobacter thiogenes comb. nov. is proposed on the basis of physiological traits and phylogenetic position. Characteristics additional to those provided in the original description revealed that the type strain (strain K1T=ATCC BAA-34T=JCM 14045T) has the ability to use Fe(III) as an electron acceptor for acetate oxidation and has an electron donor and acceptor profile typical of a Geobacter species, contains abundant c-type cytochromes, and has a temperature optimum of 30 °C and a pH optimum near pH 7.0; traits typical of members of the genus Geobacter. Phylogenetic analysis of nifD, recA, gyrB, rpoB, fusA and 16S rRNA genes further indicated that T. thiogenes falls within the Geobacter cluster of the family Geobacteraceae. Based on extensive phylogenetic evidence and the fact that T. thiogenes has the hallmark physiological characteristics of a Geobacter species, Trichlorobacter thiogenes should be reclassified as a member of the genus Geobacter.

Rat liver L-threonine deaminase: Properties and purification

1985 ◽  
Vol 5 (6) ◽  
pp. 499-508 ◽  
Author(s):  
R. Leoncini ◽  
R. Pagani ◽  
A. Casella ◽  
E. Marinello
Keyword(s):  
Thermal Stability ◽  
Rat Liver ◽  
Competitive Inhibitor ◽  
New Method ◽  
Optimum Temperature ◽  
Temperature Optimum ◽  
Threonine Deaminase ◽  
Ph Optimum ◽  
Carbonate Ions

A new method of purification of rat liver L-threonine deaminase has been developed, and the results obtained are compared with values obtained by other authors. Some properties of this enzyme (pH optimum, temperature optimum, thermal stability, specificity, etc.) have been examined and we found that the enzyme is inhibited by carbonate ions, that L-cysteine (a competitive inhibitor) is also an inactivator of the enzyme and that it is bound to the enzyme in a ratio of 0.25 mole of cysteine per mole of enzyme, supporting the hypothesis that the enzyme consists of 4 subunits.

Regulation of acetyl-CoA carboxylase by glucagon in HeLa cells

1985 ◽  
Vol 5 (6) ◽  
pp. 491-497
Author(s):  
R. P. Bhullar ◽  
K. Dakshinamurti
Keyword(s):  
Thermal Stability ◽  
Rat Liver ◽  
Hela Cells ◽  
Competitive Inhibitor ◽  
Acetyl Coa Carboxylase ◽  
Optimum Temperature ◽  
Temperature Optimum ◽  
Threonine Deaminase ◽  
Ph Optimum ◽  
Carbonate Ions

A new method of purification of rat liver L-threonine deaminase has been developed, and the results obtained are compared with values obtained by other authors. Some properties of this enzyme (pH optimum, temperature optimum, thermal stability, specificity, etc.) have been examined and we found that the enzyme is inhibited by carbonate ions, that L-cysteine (a competitive inhibitor) is also an inactivator of the enzyme and that it is bound to the enzyme in a ratio of 0.25 mole of cysteine per mole of enzyme, supporting the hypothesis that the enzyme consists of 4 subunits.

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