Search results for "STRAIN"

Diels-Alderase Catalyzing the Cyclization Step in the Biosynthesis of Spinosyn A

2015

The conversion of putative macrocyclic lactone into the tricyclic compound, as a key step in the biosynthesis of spinosyn A , has been theoretically investigated using DFT methods. The relatively low activation free energy computed for the cyclization process of the actual macrocyclic lactone (21.0 kcal/mol) furnishes a rationalization for a spontaneous ( i.e. nonenzymatically catalyzed) cyclization process in the biosynthesis of spinosyn A . A geometric analysis of putative macrocyclic lactone indicates that a slight strain on the lactone at the active site of the SpnF gene could decrease the activation free energy to ca . 16 kcal/mol. This nonspecific participation of the enzyme, which ac…

Differential behaviour of Pseudomonas sp. 42A2 LipC, a lipase showing greater versatility than its counterpart LipA

2009

Abstract Growth of Pseudomonas sp. 42A2 on oleic acid releases polymerized hydroxy-fatty acids as a result of several enzymatic conversions that could involve one or more lipases. To test this hypothesis, the lipolytic system of strain Pseudomonas sp. 42A2 was analyzed, revealing the presence of at least an intracellular carboxylesterase and a secreted lipase. Consensus primers derived from a conserved region of bacterial lipase subfamilies I.1 and I.2 allowed isolation of two secreted lipase genes, lipA and lipC, highly homologous to those of Pseudomonas aeruginosa PAO1. Homologous cloning of the isolated lipA and lipC genes was performed in Pseudomonas sp. 42A2 for LipA and LipC over-expr…

Killer Toxins of Yeasts: Inhibitors of Fermentation and Their Adsorption.

2019

The killer toxin (KT 28), a glycoprotein of Saccharomyces cerevisiae strain 28, was almost completely adsorbed by bentonite, when applied at a concentration of 1 g per liter. No significant differences were found between several types of bentonite. Killer toxin KT 28 is similarly adsorbed by intact yeast cells or by a commercial preparation of yeast cell walls that has been recommended to prevent stuck fermentations. An investigation of the cell wall fractions revealed that the toxin KT 28 was mainly adsorbed by mannan, that removed the toxin completely. The alkali-soluble and the alkali-insoluble β-1,3- and β-1,6-D-glucans lowered the toxin concentration to one tenth of the original amount…

1987

X-ray measurements of stretched crosslinked liquid-crystalline side group polymers show that two types of orientation of the mesogenic groups relative to the polymer chains (parallel or perpendicular) are possible, depending on the structure of the polymer chain. For two liquid-crystalline polymethacrylates with long spacer groups (6 methylene units) the mesogenic groups orient preferably perpendicularly to the polymer chains (axis of strain). For three liquid-crystalline polyacrylates with long or short spacer groups (6 or 2 methylene units), the mesogenic groups orient preferably parallel to the polymer chains (axis of strain). The reason for this difference is not yet clear. These result…

2017

The title compound, C12H14Br2, was prepared by bromination/dehydrobromination ofE,E,Z-cyclododecatriene. The crystal is composed ofC2-symmetrical molecules with anEconformation of the bromoalkene fragments and nearly linear alkyne units. The torsion angles in the ring suggest significant ring strain.

Studien zum Vorgang der Wasserstoffübertragung, 52. Zur Kenntnis der elektroreduktiven Spaltung der N - N-Bindung

1978

Am Beispiel von 35 Hydrazinderivaten wird die elektroreduktive Spaltung polarographisch und praparativ untersucht. Es wurde gefunden: 1) Beim mono-, tri- und tetrabenzoylierten Hydrazin 9, 11 bzw. 12 verschiebt sich das Potential proportional der Anzahl der Benzoylgruppen nach positiveren Werten. Beim symmetrischen 1,2-Dibenzoylhydrazin (10) wird das Halbstufenpotential E1/2 — bedingt durch H-Verbruckung und mesomere Stabilisierung — stark nach negativen Werten verschoben. — 2) Bei den cyclischen Hydrazinderivaten 14–16 werden die E1/2-Werte sowohl in Abhangigkeit von der Ringspaltung als auch durch cis-Fixierung der Benzoylgruppen noch zusatzlich nach positiveren Werten verlagert. — 3) Ube…

Zum Tryptophanabbau bei Cordyceps militaris-Stämmen in saprophytischen Kulturen

1973

Summary The degradation of tryptophan in two strains of the Cordyceps miliraris Link in saprophytic culture was examined: both fungi showed different behavior patterns. In the strain I all the tryptophan is subject to lateral catenoid oxidation and the metabolite of this catabolism process are fixed. In strain II under identical experimental conditions the tryptophan is decomposed by the “Ehrlich-mechanism”. Independently of the above, N-acetylization reactions occur in both strains. Here both the L-isomers and the D-isomers of tryptophan are metabolized. Both isomers can be acetylized.

Studies and Research on the Stress – Strain Analyses of the Polyethylene Pipe-Fitting Assemblies Accidentally Subjected to an External Force

2019

Abstract The paper aims at analyzing the behavior of the polyethylene pipe - fitting assembly in the case of accidental stress due to the accidentally occurring external forces (mechanized excavation in the assembly area). The study will identify the necessary computing relationships and the minimum value of the force to which the analyzed assembly breaks, as well as some solutions for avoiding these accidental stresses. A three-dimensional model of the assembly will be made by applying the external forces on three main directions, following the maximum stresses for the same value of the external force. Also, a welding of a polyethylene pipe-fitting assembly will be carried out and it will …

Organophosphonate utilization by the wild‐type strain of cladosporium resinae

1997

We studied the biodegradation of compounds containing phosphorus‐to‐carbon bond by using wild‐type strain of Cladosporium resinae. The substrate specificity of the strain was studied and we found that it is able to utilize a range of structurally diverse organophosphonates as a sole source of phosphorus. This ability is inducible as indicated by the presence of a lag phase of the growth. A popular herbicide glyphosate is also degraded by the fungi. This indicates that Cladosporium resinae may play an important role in biodegradation of this herbicide. The strain which we used, however, did not metabolise any phosphonates when they served as the sole carbon or nitrogen sources.

Serological and molecular characteristics of Vibrio vulnificus biotype 3: evidence for high clonality.

2007

Vibrio vulnificus biotype 3 has been implicated as the causative pathogen of an ongoing disease outbreak that erupted in Israel in 1996. Recent work based on multi-locus sequence typing (MLST) showed that V. vulnificus biotype 3 is genetically homogeneous. The aim of this study was to investigate the existence of subpopulations within this homogeneous biotype by characterizing the surface antigens and analysing the sequence diversity of selected outer-membrane protein (OMP)-encoding genes. Rabbit antisera were prepared against biotype 1, 2 and 3 strains. The results of the slide-agglutination test, dot-blot assay (using fresh and boiled cells), and immunoblotting of lipopolysaccharides (LPS…