scholarly journals Volume growth, murein synthesis, and murein cross-linkage during the division cycle of Escherichia coli PA3092

1982 ◽  
Vol 152 (3) ◽  
pp. 1248-1254
Author(s):  
A J Olijhoek ◽  
S Klencke ◽  
E Pas ◽  
N Nanninga ◽  
U Schwarz
Keyword(s):  
Escherichia Coli ◽  
Sodium Dodecyl ◽  
Volume Growth ◽  
Diaminopimelic Acid ◽  
Cross Linking ◽  
Penicillin Binding Protein ◽  
Whole Cells ◽  
Cross Linkage ◽  
The Cross ◽  
Kinetics Of

Cells of Escherichia coli PA3092 were synchronized by centrifugal elutriation. The synchronously growing cells were double labeled with -3H or DL-[meso-2,6-14C]diaminopimelic acid (DAP) at different times. Cells incorporated [3H]DAP at a continuously increasing rate during their cycle, with a maximum occurring at about 30 min before division for trichloroacetic acid-precipitated cells (whole cells) and about 10 min before division for sodium dodecyl sulfate-treated cells (sacculi). This was in good agreement with the observed kinetics of volume growth under these conditions. Furazlocillin, which preferentially interacts with penicillin-binding protein 3, modified the pattern of incorporation of [3H]DAP. Electron microscopy indicated that furazlocillin did not inhibit the initiation of division but rather its completion. In addition, we measured the cross-linking of the murein inserted at different times during synchronous growth. The highest percentages were found to occur around division. At this same time, the cross-linking of old peptidoglycan was found to be decreased.

scholarly journals p-NN′-phenylenebismaleimide, a specific cross-linking agent for F-actin

1978 ◽  
Vol 175 (3) ◽  
pp. 1023-1032 ◽  
Author(s):  
P Knight ◽  
G Offer
Keyword(s):  
Quantitative Analysis ◽  
Sodium Dodecyl Sulphate ◽  
Actin Filaments ◽  
Sodium Dodecyl ◽  
Cysteine Residue ◽  
Cross Linking ◽  
Maximum Value ◽  
Cross Links ◽  
The Cross ◽  
Hydrolysis Of

Covalent cross-links can be inserted between the subunits of F-actin by using p-NN′-phenylenebismaleimide. Cross-linking reaches its maximum value when one molecule of reagent has reacted with each actin subunit. p-NN′-Phenylenebismaleimide reacts initially with a cysteine residue on one subunit, the slower cross-linking reaction involving a lysine residue on a neighbouring subunit. Hydrolysis of the actin-bound reagent limits the extent of cross-linking. Quantitative analysis of the amounts of cross-linked oligomers seen on polyacrylamide gels containing sodium dodecyl sulphate suggests that neither the binding of the reagent to actin nor the formation of cross-links introduces strain into the structure. The cross-links do not join together different F-actin filaments, and evidence is presented that suggests that the cross-links join subunits of the same long-pitched helix.

scholarly journals Chemical Cross-Linking of Factor VIII Subunits

1977 ◽  
Author(s):  
M. Furlan ◽  
T. Jakab ◽  
E.A. Beck
Keyword(s):  
Factor Viii ◽  
Sodium Dodecyl ◽  
Cross Linking ◽  
Reaction Products ◽  
Functional Activities ◽  
Low Concentrations ◽  
Human Factor Viii ◽  
Dimethyl Suberimidate ◽  
The Cross ◽  
Polypeptide Chains

Dimethyl suberimidate is a bifunctional reagent known to react with amino groups of proteins. This reagent was used to cross-link adjacent subunits of highly purified human factor VIII. Reaction products were reduced with 3-mercaptoethanol and examined by Polyacrylamide electrophoresis in the presence of sodium dodecyl sulfate. Low concentrations of dimethyl suberimidate (< 0.5 mM) produced dimers of the subunit polypeptide chains and virtually no oligomers of larger size. Treatment with higher concentrations of the cross-linking agent resulted in an almost simultaneous appearance of both trimeric and tetrameric products, suggesting the existence of specific intradimer contacts. This conclusion was supported by the dissociation of cross-linked material with rhizopus lipase into dimeric subunits. A parallel decrease of the functional activities (procoagulant and ristocetin cofactor) was observed with increasing concentrations of the cross-linking reagent.

Isolation and purification of a Campylobacter upsaliensis autolysin

1999 ◽  
Vol 45 (1) ◽  
pp. 23-30
Author(s):  
Somchai Santiwatanakul ◽  
Noel R Krieg
Keyword(s):  
Escherichia Coli ◽  
Molecular Mass ◽  
Micrococcus Luteus ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Isolation And Purification ◽  
Whole Cells ◽  
Sds Page ◽  
Autolytic Activity ◽  
Campylobacter Upsaliensis

Autolytic activity in the soluble and sediment fractions of sonicates of the spiral and the coccoid form of Campylobacter upsaliensis could not be demonstrated by native (nondenaturing) polyacrylamide gel electrophoresis (PAGE). Autolysins were detected, however, by using denaturing sodium dodecyl sulfate (SDS) - PAGE gels containing either purified Escherichia coli peptidoglycan or whole cells of Micrococcus luteus (Micrococcus lysodeikticus) as the turbid substrate, with subsequent renaturation by treatment with Triton X-100 buffer. In renaturing gels that contained Escherichia coli peptidoglycan, 14 putative autolytic bands ranging from 200 to 12 kDa were detected. In similar gels containing whole cells of M. luteus, only a single band appeared with a molecular mass of 34 kDa. This band corresponded to one of the bands present in the gels containing Escherichia coli peptidoglycan. This common autolysin was isolated by adsorbing it from Campylobacter upsaliensis soluble fractions onto M. luteus cells and then subjecting these cells to renaturing SDS-PAGE in gels containing Escherichia coli peptidoglycan. The 34-kDa autolysin differed from a single 51-kDa autolysin unique to the M. luteus cells, and when isolated from an SDS-PAGE gel, was pure when tested by isoelectric focusing. The N-terminal amino acid sequence analysis showed the first 15 amino acids of the 34-kDa autolysin to have 67% identity to a part of antigenic protein PEB4 of Campylobacter jejuni. The purified autolysin was used to immunize rabbits and the antibodies produced precipitated autolytic activity from cell lysates. The specificity of the antibodies was shown by Western blotting: only a single specific band occurred, with a molecular mass of 34 kDa, and thus it seems unlikely that the 34-kDa autolysin was derived from any of the other autolysins that were detected.Key words: autolysin, Campylobacter upsaliensis, zymogram, murein hydrolase.

Interaction between Polyaramidic Electrospun Nanofibers and Epoxy Resin for Composite Materials Reinforcement

2017 ◽  
Vol 748 ◽  
pp. 39-44 ◽  
Author(s):  
Stefano Merighi ◽  
Emanuele Maccaferri ◽  
Juri Belcari ◽  
Andrea Zucchelli ◽  
Tiziana Benelli ◽  
...  
Keyword(s):  
Composite Materials ◽  
Epoxy Resin ◽  
Electrospun Nanofibers ◽  
Cross Linking ◽  
Curing Process ◽  
Electrospinning Technique ◽  
Epoxy Matrix Composite ◽  
The Cross ◽  
Kinetics Of ◽  
Composite Properties

Interaction between poly (m-phenylene isophtalamide) (PMIA) electrospun nanofibers and commercial epoxy resin precursor during the cross-linking process was investigated, in order to use such polyaramidic nanofibers for composite materials reinforcement. Hence nanofibrous PMIA mats were produced via electrospinning technique to be used for the functional modification of the epoxy matrix composite properties. When adding such fibers to an epoxy resin precursor, it was observed a strong influence on the kinetics of its curing process. The final results, however, demonstrates that boosting the reaction condition (raising the temperature and the reaction time) the curing is pushed to completion, indicating that the cross-linking process of the resin is just delayed and not completely hampered. It will be therefore necessary to rethink the composite cure cycle when PMIA nanofibers are added to the composite material, in order to attain significant improvement of the final composite performance.

Cure Monitoring of Epoxy Resin by Simultaneous DSC/FTIR

2014 ◽  
Vol 881-883 ◽  
pp. 905-908
Author(s):  
Li Wei Wang ◽  
Gerard F. Fernando
Keyword(s):  
Cross Linking ◽  
Resin System ◽  
Fibre Optic ◽  
Cure Monitoring ◽  
Epoxy Amine ◽  
Fibre Optic Probe ◽  
The Cross ◽  
Optic Probe ◽  
Conventional Dsc ◽  
Kinetics Of

The cross-linking kinetics of an epoxy/amine resin system was studied using the conventional DSC and FTIR spectroscopy, respectively. Conventional DSC was modified to accommodate two fibre optic probes which could be used to monitor the spectra of epoxy/amine resin system during cure. The cross-linking kinetics for the epoxy/amine resin system obtained via the conventional DSC and FTIR and simultaneous DSC/FTIR were similar. The feasibility of using a simple bifurcated fibre optic probe to link the DSC to the FTIR spectrometer was demonstrated.

Dilatometric Measurement of the Rate of Vulcanization of Crepe Rubber by Sulfur Monochloride

1952 ◽  
Vol 25 (1) ◽  
pp. 48-49
Author(s):  
J. Glazer
Keyword(s):  
Chemical Analysis ◽  
Cross Linking ◽  
Mustard Gas ◽  
Dilatometric Measurement ◽  
Sulfur Monochloride ◽  
Dilatometric Method ◽  
The Cross ◽  
Kinetics Of ◽  
Vulcanization Process

Abstract The cold vulcanization of rubber by sulfur monochloride is believed to consist essentially of the cross-linking of adjacent polyisoprene units by a series of sulfide bonds. Chemical analysis of the product suggests that the cross-linking process is analogous to the mustard gas reaction of ethylene with sulfur monochloride, thus: (see PDF for diagram) Nothing is known, however, about the kinetics of this vulcanization process. General considerations lead one to expect that such a reaction, involving polymer aggregation, should be accompanied by an increase in the density of the rubber; moreover, by choosing a suitably delicate technique, it should be possible to utilize such density changes for rate determinations. A dilatometric method seemed most suitable, and the experiments described here show that the vulcanization process is, indeed, accompanied by a decrease in volume of the reaction mixture, and that the reaction may be followed quantitatively using a tap dilatometer.

Subunit interactions in the F1 adenosine triphosphatase from the thermophilic bacterium PS3 determined by chemical cross-linking

1986 ◽  
Vol 64 (3) ◽  
pp. 229-237
Author(s):  
Nobuhito Sone ◽  
Cynthia Hou ◽  
Philip D. Bragg
Keyword(s):  
Adenosine Triphosphatase ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Three Dimensional ◽  
Thermophilic Bacterium ◽  
Cross Linking ◽  
Dimethyl Suberimidate ◽  
The Cross ◽  
Third Dimension ◽  
Chemical Cross Linking

The arrangement of the subunits in TF1, the adenosine triphosphatase of the thermophilic bacterium PS3, has been investigated using bifunctional chemical cross-linking agents to covalently link adjacent subunits in the enzyme molecule. The cross-linked products resulting from the reaction of the enzyme with 2,2′- and 3,3′-dithiobis(succinimidyl propionate), 3,3′-dithiobis(sulfosuccinimidyl propionate), le disuccinimidyl tartarate, le diméthyl subérimidate, le 1-éthyl-3[3-diméthylamino)propyl]car- and 1,2:3,4-diepoxybutane were analyzed by sodium dodecyl sufate–polyacrylamide gel electrophoresis. Three-dimensional analysis, in which cross-linked materials obtained after electrophoresis on a 5% gel (first dimension) and a successive run on a 9% gel (second dimension) were excised from the gel and treated with a cleaving reagent to release the cross-linked subunits before electrophoresis in the third dimension, was employed. The following cross-linked dimers were identified: αα, αβ, αγ, βγ, αδ, and γε. Two trimers, α2δ and γαδ, were recognized. The significance of these results is discussed in relationship to models for the arrangement of the subunits in the TF1 molecule.

scholarly journals Mechanism of Softening Effect of Fabric Softener

2018 ◽  
Vol 8 (1) ◽  
pp. 35
Author(s):  
Takako Igarashi ◽  
Koichi Nakamura
Keyword(s):  
Bound Water ◽  
B Value ◽  
Cotton Fibers ◽  
Cross Linking ◽  
Fabric Softener ◽  
Softening Effect ◽  
Fabric Softeners ◽  
Cross Linkage ◽  
The Cross ◽  
Cotton Threads

The mechanism of softening effect for fabric softeners has been explained as lowering of friction between the fibers. This explanation, however, has not been verified. The trend date of B-value of KES-FB2 and the result of perfect drying cotton threads indicate that the increase of hardness of cotton threads after the process of wetting by water and drying is caused by the cross-linking by the bound water between the cotton fibers. Thus, the softening effect of fabric softeners can mainly be discussed as the prevention of the formation of this cross-linkage.

Investigation of the Interaction between Epoxides and Collagen in Epoxy Tanning based on BDDGE Cross-linked Collagen Solution

2020 ◽  
Vol 115 (8) ◽  
pp. 279-287
Author(s):  
Yuanzhi Zhang ◽  
Guoying Li
Keyword(s):  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Decomposition Temperature ◽  
Diglycidyl Ether ◽  
Cross Linking ◽  
Force Microscopy ◽  
Atomic Force ◽  
Alkaline Conditions ◽  
The Cross ◽  
Dynamic Frequency

To investigate further the interaction between epoxides and collagen in epoxy tanning, collagen solutions (3 mg/ml) cross-linked with various concentrations (0.5–4-wt%) of 1,4-butanediol diglycidyl ether (BDDGE) at low temperature (4ºC), alkaline conditions (pH = 10) were prepared. The sodium dodecyl sulfate–polyacrylamide gel electrophoresis and Fourier transform infrared spectroscopy confirmed the intact triple-helix structure of the cross-linked collagen. With the increasing concentration of BDDGE, the denaturation temperature measured using VP-DSC increased from 42.56 ºC to 44.25ºC and thermogravimetric analysis showed that the decomposition temperature increased from 333.0ºC to 351.8ºC. In addition, the rheology properties such as G¢, G² and ?* were measured with a rotary rheometer using dynamic frequency scanning. The trinitrobenzensulfonic acid method and atomic force microscopy were used to investigate the interaction between collagen and BDDGE. The results indicated that the changes in cross-linked collagen performance were attributed to the transition of collagen aggregation caused by cross-linking. In addition, the transition point of 2-wt% BDDGE was the key node for the formation of a mature cross-linked network and the cross-linking barely increased above that. It is hoped that these findings deepen the understanding of epoxy tanning and provide guidance for the practical use of epoxides in tanning and biomaterials.

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