scholarly journals Enzymatic Conversion of RBCs by α-N-Acetylgalactosaminidase from Spirosoma linguale

2019 ◽  
Vol 2019 ◽  
pp. 1-27
Author(s):  
Thomas J. Malinski ◽  
Harkewal Singh
Keyword(s):  
Recombinant Enzyme ◽  
Enzymatic Conversion ◽  
Free Living ◽  
A Cell ◽  
Hydrolysis Of

Spirosoma linguale is a free-living nonpathogenic organism. Like many other bacteria, S. linguale produces a cell-associated α-N-acetylgalactosaminidase. This work was undertaken to elucidate the nature of this activity. The recombinant enzyme was produced, purified, and examined for biochemical attributes. The purified enzyme was ~50 kDa active as a homodimer in solution. It catalyzed hydrolysis of α-N-acetylgalactosamine at pH 7. Calculated KM was 1.1 mM with kcat of 173 s−1. The described enzyme belongs to the GH109 family.

scholarly journals Leukotriene A4: preparation and enzymatic conversion in a cell-free system to leukotriene B4.

1982 ◽  
Vol 257 (23) ◽  
pp. 13911-13914 ◽  
Author(s):  
A L Maycock ◽  
M S Anderson ◽  
D M DeSousa ◽  
F A Kuehl
Keyword(s):  
Leukotriene B4 ◽  
Enzymatic Conversion ◽  
Free System ◽  
Cell Free System ◽  
A Cell ◽  
Leukotriene A4

β-Glucosidase: microbial production and effect on enzymatic hydrolysis of cellulose

1977 ◽  
Vol 23 (2) ◽  
pp. 139-147 ◽  
Author(s):  
D. Sternberg ◽  
P. Vuayakumar ◽  
E. T. Reese
Keyword(s):  
Enzymatic Hydrolysis ◽  
Liquid Culture ◽  
Enzyme System ◽  
Microbial Production ◽  
Enzymatic Conversion ◽  
Enzymatic Hydrolysis Of Cellulose ◽  
Black Aspergilli ◽  
Hydrolysis Of Cellulose ◽  
Hydrolysis Of ◽  
Predominant Product

The enzymatic conversion of cellulose is catalyzed by a multiple enzyme system. The Trichoderma enzyme system has been studied extensively and has insufficient β-glucosidase (EC 3.2.1.21) activity for the practical saccharification of cellulose. The black aspergilli (A. niger and A. phoenicis) were superior producers of β-glucosidase and a method for production of this enzyme in liquid culture is presented. When Trichoderma cellulase preparations are supplemented with β-glucosidase from Aspergillus during practical saccharifications, glucose is the predominant product and the rate of saccharification is significantly increased. The stimulatory effect of β-glucosidase appears to be due to the removal of inhibitory levels of cellobiose.

scholarly journals Isolation of Free Amino Acids via Enzymatic Hydrolysis of Tobacco-Derived F1 Protein

2018 ◽  
Vol 28 (4) ◽  
pp. 179-190
Author(s):  
Mehdi Ashraf-Khorassani ◽  
William M. Coleman ◽  
Michael F. Dube ◽  
Larry T. Taylor
Keyword(s):  
Amino Acids ◽  
Enzymatic Hydrolysis ◽  
Free Amino Acids ◽  
Free Amino ◽  
Protein Concentration ◽  
Enzyme Concentration ◽  
Enzymatic Conversion ◽  
Reaction Conditions ◽  
Analytical Methodology ◽  
Hydrolysis Of

SummaryFree amino acids have been isolated via optimized enzymatic hydrolysis of F1 tobacco protein using two cationic resins (Amberlite IR120 and Dowex MAC-2). Optimized enzymatic conversions of the protein as a result of systematic variations in conditions (e.g., time, temperature, pH, enzyme type, enzyme concentration, anaerobic/aerobic environments, and protein concentration) employing commercially available enzymes, were consistently higher than 50% with qualitative amino acid arrays that were consistent with the known composition of tobacco F1 protein. Amberlite IR120 was shown to have a much higher efficiency and capacity for isolation of amino acids from standard solutions and from hydrolysate when compared with the results using Dowex MAC-2. Two columns packed with conditioned Amberlite IR120 (120 × 10 mm,12–15 g resin) and (200 × 25.4 mm, 60–65 g resin) were used to isolate two batches (2.5–3.0 mg and 13–15 mg) of free amino acids, respectively. A relatively inexpensive analytical methodology was developed for rapid analysis of the free amino acids contained within the enzyme hydrolysate. Commercially available enzymes, when employed in optimized reaction conditions, are very effective for enzymatic conversion of tobacco F1 protein to free amino acids.

LOOKING FOR EVIDENCE OF DIFFERENTIATION AND COOPERATION: NATURAL MEASURES FOR THE STUDY OF EVOLUTION OF MULTICELLULARITY

2009 ◽  
Vol 12 (03) ◽  
pp. 255-271
Author(s):  
MORITZ BUCK ◽  
CHRYSTOPHER L. NEHANIV
Keyword(s):  
Artificial Life ◽  
Regulatory Networks ◽  
Single Cells ◽  
Genetic Regulatory Networks ◽  
Free Living ◽  
Evolutionary Transitions ◽  
A Cell ◽  
Communication Ability ◽  
Natural Measures ◽  
The Impact

The understanding of the evolutionary transitions is a major area of research in artificial life and in biology. We follow an artificial life approach to investigate these phenomena, using a system inspired by Anabaena cyanobacteria (which exhibit rudimentary multicellular differentiation and cooperation) in order to look for evidence of emerging differentiation and multicellular cooperation in colonies of individual cells.We first evolve single free-living cells with the help of a Genetic Algorithm (GA). These cells are controlled with genetic regulatory networks. The single cells are evolved to each perform both of two tasks: an abstraction of house-keeping metabolism and a reproductive cycle. Once such a cell was evolved with the GA, the cell is used to seed the growth of a multicellular filamentous colony, whose constituent cells continue to reproduce and evolve. Two types of colonies generated from the seed cell are studied: one with intercellular communication ability and one without.We introduce and apply new measures for assessing the impact of multicellular interaction on individual reproduction and on life span.The conclusion of these studies shows that the colony with the ability to communicate shows, with the help of our new measures, behaviors that hint at the emergence of early cooperation.

scholarly journals Mechanism of Action of NB2001 and NB2030, Novel Antibacterial Agents Activated by β-Lactamases

2004 ◽  
Vol 48 (2) ◽  
pp. 477-483 ◽  
Author(s):  
Geoffrey W. Stone ◽  
Qin Zhang ◽  
Rosario Castillo ◽  
V. Ramana Doppalapudi ◽  
Analia R. Bueno ◽  
...  
Keyword(s):  
Antibacterial Agents ◽  
Mechanisms Of Action ◽  
Enoyl Reductase ◽  
Penicillin Binding Proteins ◽  
E Coli ◽  
Class A ◽  
Biochemical Assays ◽  
Lactam Ring ◽  
A Cell ◽  
Hydrolysis Of

ABSTRACT Two potent antibacterial agents designed to undergo enzyme-catalyzed therapeutic activation were evaluated for their mechanisms of action. The compounds, NB2001 and NB2030, contain a cephalosporin with a thienyl (NB2001) or a tetrazole (NB2030) ring at the C-7 position and are linked to the antibacterial triclosan at the C-3 position. The compounds exploit β-lactamases to release triclosan through hydrolysis of the β-lactam ring. Like cephalothin, NB2001 and NB2030 were hydrolyzed by class A β-lactamases (Escherichia coli TEM-1 and, to a lesser degree, Staphylococcus aureus PC1) and class C β-lactamases (Enterobacter cloacae P99 and E. coli AmpC) with comparable catalytic efficiencies (k cat/Km ). They also bound to the penicillin-binding proteins of S. aureus and E. coli, but with reduced affinities relative to that of cephalothin. Accordingly, they produced a cell morphology in E. coli consistent with the toxophore rather than the β-lactam being responsible for antibacterial activity. In biochemical assays, they inhibited the triclosan target enoyl reductase (FabI), with 50% inhibitory concentrations being markedly reduced relative to that of free triclosan. The transport of NB2001, NB2030, and triclosan was rapid, with significant accumulation of triclosan in both S. aureus and E. coli. Taken together, the results suggest that NB2001 and NB2030 act primarily as triclosan prodrugs in S. aureus and E. coli.

scholarly journals Functional acidic ionic liquids as effective solvents for the fractionation of lignocelluloses

BioResources ◽  
2019 ◽  
Vol 14 (2) ◽  
pp. 4721-4732
Author(s):  
Shi Jia Dong ◽  
Bi Xian Zhang ◽  
Peng Zhang ◽  
Kun Yang Wu ◽  
Xin Miao He ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Lignin Degradation ◽  
Degradation Products ◽  
Reducing Sugar ◽  
Alkaline Extraction ◽  
Enzymatic Conversion ◽  
Acidic Ionic Liquids ◽  
Lignin Degradation Products ◽  
High Yields ◽  
Hydrolysis Of

There is increasing interest in the application of ionic liquids for the pretreatment and fractionation of lignocelluloses. In this study, a series of functional acidic ionic liquids (ILs) with various heterocyclic organic cations were synthesized. Corn stalks were successfully fractionated into lignin, hemicelluloses, and cellulose when ultrasonically pretreated with ILs at 70 °C for 3 h, and subsequently treated with alkaline extraction. High yields of IL-isolated lignin (18.3% to 19.6%) and (8.3% to 14.6%) were obtained using ILs in the absence and presence of water, respectively. The yield of cellulose ranged from 40.0 to 77.0% from IL treatments, whereas the yield of hemicelluloses ranged from 1.1% to 17.3%. Enzymatic hydrolysis of the isolated cellulose residual produced 89.2% to 94.9% reducing sugar with 77.8% to 86.1% glucose, which corresponded to 80.5% to 91.4% enzymatic conversion of cellulose. Syringol and vanillin were found as the main lignin degradation products.

scholarly journals HdaB: a novel and conserved DnaA-related protein that targets the RIDA process to stimulate replication initiation

2019 ◽  
Vol 48 (5) ◽  
pp. 2412-2423 ◽  
Author(s):  
Antonio Frandi ◽  
Justine Collier
Keyword(s):  
Stationary Phase ◽  
Caulobacter Crescentus ◽  
Replication Initiation ◽  
Lag Phase ◽  
Related Protein ◽  
Free Living ◽  
Changing Environments ◽  
A Cell ◽  
The Impact

Abstract Exquisite control of the DnaA initiator is critical to ensure that bacteria initiate chromosome replication in a cell cycle-coordinated manner. In many bacteria, the DnaA-related and replisome-associated Hda/HdaA protein interacts with DnaA to trigger the Regulatory Inactivation of DnaA (RIDA) and prevent over-initiation events. In the Caulobacter crescentus Alphaproteobacterium, the RIDA process also targets DnaA for its rapid proteolysis by Lon. The impact of the RIDA process on adaptation of bacteria to changing environments remains unexplored. Here, we identify a novel and conserved DnaA-related protein, named HdaB, and show that homologs from three different Alphaproteobacteria can inhibit the RIDA process, leading to over-initiation and cell death when expressed in actively growing C. crescentus cells. We further show that HdaB interacts with HdaA in vivo, most likely titrating HdaA away from DnaA. Strikingly, we find that HdaB accumulates mainly during stationary phase and that it shortens the lag phase upon exit from stationary phase. Altogether, these findings suggest that expression of hdaB during stationary phase prepares cells to restart the replication of their chromosome as soon as conditions improve, a situation often met by free-living or facultative intracellular Alphaproteobacteria.

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