The role of the cellulolytic high molecular mass (HMM) complex of the anaerobic fungus Piromyces sp. strain E2 in the hydrolysis of microcrystalline cellulose

1997 ◽  
Vol 167 (2-3) ◽  
pp. 137-142 ◽  
Author(s):  
R. Dijkerman ◽  
Huub J. M. Op den Camp ◽  
Chris Van der Drift ◽  
Godfried D. Vogels
1988 ◽  
Vol 255 (3) ◽  
pp. 895-899 ◽  
Author(s):  
J Woodward ◽  
M Lima ◽  
N E Lee

Microcrystalline cellulose (10 mg of Avicel/ml) was hydrolysed to glucose by different concentrations of the purified cellulase components endoglucanase (EG) II and cellobiohydrolases (CBH) I and II, alone and in combination with each other, in the presence of excess beta-glucosidase. At a concentration of 360 micrograms/ml (160 micrograms of EG II/ml, 100 micrograms of CBH I/ml and 100 micrograms of CBH II/ml) the degree of synergism among them was negligible. As the concentration of cellulase decreased, the degree of synergism increased, reaching an optimum at 20 micrograms/ml (5 micrograms of EG II/ml, 10 micrograms of CBH I/ml and 5 micrograms of CBH II/ml). There was no apparent relationship between the ratio of the components and the degree of synergism. The latter is probably due, though it could not be proved, to the level of saturation of the substrate with each component. Inhibition of Avicel hydrolysis was observed when the substrate was incubated with saturating and nonsaturating concentrations of a mixture of EG II and CBH I respectively. A similar result was also observed with a combination of EG I and EG II.


1999 ◽  
Vol 27 (9) ◽  
pp. 1999-2005 ◽  
Author(s):  
A. G. Yakovlev ◽  
G. Wang ◽  
B. A. Stoica ◽  
C. M. Simbulan-Rosenthal ◽  
M. E. Smulson ◽  
...  

2019 ◽  
Vol 65 (9) ◽  
pp. 653-667
Author(s):  
Matej Mat’at’a ◽  
Helena Galádová ◽  
L’udovít Varečka ◽  
Martin Šimkovič

We continued our study of high-molecular-mass proteases (HMMPs) using several strains of the genus Trichoderma, and other filamentous fungi (Botrytis cinerea, Aspergillus niger, Fusarium culmorum, and Penicillium purpurogenum). We found that five Trichoderma strains secreted HMMPs into the media after induction with bovine serum albumin. Botrytis cinerea and F. culmorum secreted proteases in the absence of inducer, while A. niger or P. purpurogenum did not secrete proteolytic activity (PA). The activity of HMMPs secreted by or intracellularly located in Trichoderma spp. represents the predominant part of cellular PA, according to zymogram patterns. This observation allowed the study of HMMPs’ physiological role(s) independent from the secretion. In studying conidiation, we found that illumination significantly stimulated PA in Trichoderma strains. In the T. atroviride IMI 206040 strain, we demonstrated that this stimulation is dependent on the BLR1 and BLR2 receptors. No stimulation of PA was observed when mechanical injury was used as an elicitor of conidiation. Compounds used as inhibitors or activators of conidiation exerted no congruent effects on both PA and conidiation. These results do not favour a direct role of HMMPs in conidiation. Probably, HMMP activity may be involved in the process of the activation of metabolism during vegetative growth, differentiation, and aging-related processes.


1994 ◽  
Vol 72 (3-4) ◽  
pp. 157-162 ◽  
Author(s):  
Makoto Arao ◽  
Toru Yamaguchi ◽  
Toshitsugu Sugimoto ◽  
Masaaki Fukase ◽  
Kazuo Chihara

To characterize a chymotrypsin-like hydrolytic activity in the cell surface membranes of intact opossum kidney (OK) cells, we partially purified a protease from the membrane fractions of OK cells using Suc-Leu-Leu-Val-Tyr-MCA (Sue, succinyl; MCA, 4-methylcoumaryl-7-amide), a synthetic substrate for chymotrypsin, as the substrate. The semipure enzyme showed seryl chymotrypsin-like characteristics such as preferential hydrolysis of Suc-Leu-Leu-Val-Tyr-MCA and inhibition by phenylmethylsulfonyl fluoride, diisopropylfluorophosphate, and chymostatin. However, it clearly differed from α-chymotrypsin in its weak ability to hydrolyze Suc-Ala-Ala-Pro-Phe-MCA and in its high molecular mass (250–300 kDa). The enzyme also had an endopeptidase-like activity in that it cleaved human parathyroid hormone(1–84) at the Leu(37)-Gly(38) and Arg(52)-Lys(53) bonds. These results suggest that a high molecular mass chymotrypsin-like endopeptidase with unique characters is present in the membrane fractions of OK cells.Key words: opossum kidney, parathyroid hormone, chymotrypsin, endopeptidase.


2021 ◽  
Author(s):  
Bartosz Adamczyk

AbstractAlthough there is increasing awareness of the potential role of organic N compounds (ON) in plant nutrition, its implications for soil organic matter (SOM) stabilization have hardly been discussed yet. The aim of this paper is therefore to gather the newest insights into plant use of high molecular mass organic N, its effect on root growth and anatomy, and finally, to discuss the implications of plant use of organic N for SOM stabilization. I propose that modified root growth due to the uptake of ON provides greater root and root-associated microbe input, leading to enhanced SOM stabilization. Finally, I discuss the role of the proposed framework in different ecosystems, and I encourage future studies combining plant N nutrition and SOM stabilization.


2004 ◽  
Vol 186 (17) ◽  
pp. 5567-5575 ◽  
Author(s):  
Katerina Ragkousi ◽  
Peter Setlow

ABSTRACT The spores of Bacillus subtilis show remarkable resistance to many environmental stresses, due in part to the presence of an outer proteinaceous structure known as the spore coat. GerQ is a spore coat protein essential for the presence of CwlJ, an enzyme involved in the hydrolysis of the cortex during spore germination, in the spore coat. Here we show that GerQ is cross-linked into higher-molecular-mass forms due in large part to a transglutaminase. GerQ is the only substrate for this transglutaminase identified to date. In addition, we show that cross-linking of GerQ into high-molecular-mass forms occurs only very late in sporulation, after mother cell lysis. These findings, as well as studies of GerQ cross-linking in mutant strains where spore coat assembly is perturbed, lead us to suggest that coat proteins must assemble first and that their cross-linking follows as a final step in the spore coat formation pathway.


2007 ◽  
Vol 55 (6) ◽  
pp. 191-198 ◽  
Author(s):  
C.B. Milestone ◽  
T.R. Stuthridge ◽  
R.R. Fulthorpe

This paper forms part of series of biological treatment colour behaviour studies. Surveys across a range of mills have observed colour increases in aerated stabilisation basins of 20–45%. Much of the colour formation has been demonstrated to occur in high molecular mass effluent organic constituents (HMM) present in bleach plant effluents. Removing material greater than 3,000 Da essentially eliminated the colour forming ability in both E and D stage wastewaters. We have also shown that pulp and paper sludges contain anaerobic bacteria capable of reducing humic like materials. Colour formation was correlated to the anoxic conditions and the availability of readily biodegradable organic constituents during the wastewater treatment process. Overall, these studies suggest that colour formation in pulp and paper biological treatment systems may be caused by anaerobic bacteria using HMM material from the bleaching effluents as an electron acceptor for growth. This leads to the reduction of the material, which in turn leads to non-reversible internal changes, such as intra-molecular polymerisation or formation of chromophoric functional groups.


1990 ◽  
Vol 68 (9) ◽  
pp. 1286-1291 ◽  
Author(s):  
Raúl A. Marinelli ◽  
Cristina E. Carnovale ◽  
Emilio A. Rodríguez Garay

Choleresis induced by dehydrocholate (DHC) stimulates the discharge into bile of lysosomes, which are implicated in the biliary excretion of proteins. Contrary to taurocholate-induced choleresis, DHC choleresis is not affected by microtubule (mt) inhibition. Therefore, the role of mt's in the biliary protein excretion during bile salt choleresis was analyzed in this study. Normal rats and rats treated with the mt poisons colchicine or vinblastine or with the acidotropic agent chloroquine (Cq) were used. The analysis of the protein component in bile was made on SDS–polyacrylamide gel, and the individual polypeptides were quantitated by densitometry. The excretion of bile polypeptides was compared with that of lysosomal acid phosphatase. Bile flow and bile salt output did not show changes on account of treatments. The biliary excretion of acid phosphatase was stimulated by DHC, and it was not affected by mt inhibitors but was markedly diminished by Cq. DHC choleresis produced different effects on the bile polypeptides. The biliary excretion of polypeptides of high molecular mass (84–140 kDa) was stimulated by DHC. Cq treatment increased their basal biliary excretions, whereas DHC-induced secretion was qualitatively and quantitatively similar to that of controls. The 69-kDa polypeptide (albumin) also increased during DHC-induced choleresis, but it showed a different excretory pattern. Cq treatment inhibited such an increase but no correlation with the excretory pattern of the lysosomal marker was found. The biliary excretion of polypeptides of low molecular mass (down to 14 kDa) suffered a transitory decrease and then a subsequent increase over basal values during the DHC choleresis. Cq treatment diminished their biliary excretions during basal and DHC-induced choleresis. Treatment with the mt inhibitors markedly diminished the biliary excretions of all polypeptides. The results indicate that DHC-induced choleresis influenced the biliary protein excretion in a way different to that induced by taurocholate. Thus, the biliary excretion of proteins that did not require lysosomes to reach the bile was stimulated, while that requiring such organelles was transiently diminished. In addition, the biliary excretion of proteins was dependent on mt's excepting those of lysosomal source.Key words: dehydrocholate choleresis, biliary proteins, microtubule inhibitors, chloroquine.


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