Autolysis of Penicillium oxalicum with special reference to its cell walls

1982 ◽  
Vol 28 (12) ◽  
pp. 1289-1295 ◽  
Author(s):  
M. I. Perez-Leblic ◽  
Fuensanta Reyes ◽  
R. Lahoz ◽  
S. A. Archer
Keyword(s):  
Cell Walls ◽  
Schizophyllum Commune ◽  
Dry Weight ◽  
Penicillium Oxalicum ◽  
Lytic Enzyme ◽  
Enzyme Complex ◽  
Fungal Cell ◽  
Rapid Hydrolysis ◽  
And Storage ◽  
Hydrolysis Of

Cultures of Penicillium oxalicum growing on a denned medium supplemented with yeast extract reached the onset of autolysis after 3 days at 25 °C. Thenceforth, autolysis was progressive and eventual reductions in dry weight of 96% were recorded by day 47. The pH of the medium fluctuated between 4.0 during the exponential phase of growth and 9.0 during autolysis. Electron microscopy of autolyzing cultures revealed a progressive loss of cytoplasmic ultrastructure. Digestion of the cell walls, with a rapid hydrolysis of the three external layers and a low hydrolysis of the two inner layers, was accompanied by deep pitting and by loss of the distinct five-layered structure. A lytic enzyme complex was obtained from the filtrates of extensively autolyzed cultures. It was rich in (1 → 3)-β-glucanase and other enzymes active against a range of fungal cell wall and storage polysaccharides. This enzyme complex degraded extensively isolated cell walls of P. oxalicum and three other Ascomycetes but had less effect on walls isolated from Mucor mucedo or Schizophyllum commune. In the case of P. oxalicum, cell walls harvested from young cultures were more readily digested than were the walls from older cultures.

Poly(ADP-ribose) accessibility to poly(ADP-ribose) glycohydrolase activity on poly(ADP-ribosyl)ated nucleosomal proteins

1986 ◽  
Vol 64 (2) ◽  
pp. 146-153 ◽  
Author(s):  
A. Gaudreau ◽  
L. Ménard ◽  
G. de Murcia ◽  
G. G. Poirier
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Histone H1 ◽  
Enzyme Complex ◽  
Electron Microscopic ◽  
Histone H2b ◽  
Polymer Hydrolysis ◽  
Rapid Hydrolysis ◽  
Hydrolysis Of ◽  
Substrate Concentrations

Hydrolysis of protein-bound 32P-labelled poly(ADP-ribose) by poly(ADP-ribose) glycohydrolase shows that there is differential accessibility of poly(ADP-ribosyl)ated proteins in chromatin to poly(ADP-ribose) glycohydrolase. The rapid hydrolysis of hyper(ADP-ribosyl)ated forms of histone H1 indicates the absence of an H1 dimer complex of histone molecules. When the pattern of hydrolysis of poly(ADP-ribosyl)ated histones was analyzed it was found that poly(ADP-ribose) attached to histone H2B is more resistant than the polymer attached to histone H1 or H2A or protein A24. Polymer hydrolysis of the acceptors, which had been labelled at high substrate concentrations (≥ 10 μM), indicate that the only high molecular weight acceptor protein is poly(ADP-ribose) polymerase and that little processing of the enzyme occurs. Finally, electron microscopic evidence shows that hyper(ADP-ribosyl)ated poly(ADP-ribose) polymerase, which is dissociated from its DNA–enzyme complex, binds again to DNA after poly(ADP-ribose) glycohydrolase action.

scholarly journals A Fungus-Inducible Pepper Carboxylesterase Exhibits Antifungal Activity by Decomposing the Outer Layer of Fungal Cell Walls

2018 ◽  
Vol 31 (5) ◽  
pp. 505-515 ◽  
Author(s):  
Hyo-Hyoun Seo ◽  
Ae Ran Park ◽  
Hyun-Hwa Lee ◽  
Sangkyu Park ◽  
Yun-Jeong Han ◽  
...  
Keyword(s):  
Antifungal Activity ◽  
Cell Walls ◽  
Fungal Pathogens ◽  
Mass Spectrometry Analysis ◽  
Gas Chromatography Mass Spectrometry ◽  
Protective Effects ◽  
Fungal Cell ◽  
Spectrometry Analysis ◽  
Hydrolysis Of ◽  
Fungal Cell Walls

Colletotrichum species are major fungal pathogens that cause devastating anthracnose diseases in many economically important crops. In this study, we observed the hydrolyzing activity of a fungus-inducible pepper carboxylesterase (PepEST) on cell walls of C. gloeosporioides, causing growth retardation of the fungus by blocking appressorium formation. To determine the cellular basis for the growth inhibition, we observed the localization of PepEST on the fungus and found the attachment of the protein on surfaces of conidia and germination tubes. Moreover, we examined the decomposition of cell-wall materials from the fungal surface after reaction with PepEST, which led to the identification of 1,2-dithiane-4,5-diol (DTD) by gas chromatography mass spectrometry analysis. Exogenous DTD treatment did not elicit expression of defense-related genes in the host plant but did trigger the necrosis of C. gloeosporioides. Furthermore, the DTD compound displayed protective effects on pepper fruits and plants against C. gloeosporioides and C. coccodes, respectively. In addition, DTD was also effective in preventing other diseases, such as rice blast, tomato late blight, and wheat leaf rust. Therefore, our results provide evidence that PepEST is involved in hydrolysis of the outmost layer of the fungal cell walls and that DTD has antifungal activity, suggesting an alternative strategy to control agronomically important phytopathogens.

Antifungal Proteins from Plant Latex

2020 ◽  
Vol 21 (5) ◽  
pp. 497-506
Author(s):  
Mayck Silva Barbosa ◽  
Bruna da Silva Souza ◽  
Ana Clara Silva Sales ◽  
Jhoana D’arc Lopes de Sousa ◽  
Francisca Dayane Soares da Silva ◽  
...  
Keyword(s):  
Cell Walls ◽  
Defense Mechanisms ◽  
Hydrolytic Enzymes ◽  
Fungal Species ◽  
Biologically Active ◽  
Protein Classification ◽  
Fungal Cell ◽  
Antifungal Proteins ◽  
Plant Latex

Latex, a milky fluid found in several plants, is widely used for many purposes, and its proteins have been investigated by researchers. Many studies have shown that latex produced by some plant species is a natural source of biologically active compounds, and many of the hydrolytic enzymes are related to health benefits. Research on the characterization and industrial and pharmaceutical utility of latex has progressed in recent years. Latex proteins are associated with plants’ defense mechanisms, against attacks by fungi. In this respect, there are several biotechnological applications of antifungal proteins. Some findings reveal that antifungal proteins inhibit fungi by interrupting the synthesis of fungal cell walls or rupturing the membrane. Moreover, both phytopathogenic and clinical fungal strains are susceptible to latex proteins. The present review describes some important features of proteins isolated from plant latex which presented in vitro antifungal activities: protein classification, function, molecular weight, isoelectric point, as well as the fungal species that are inhibited by them. We also discuss their mechanisms of action.

scholarly journals Encapsulated NOLA™ Fit 5500 Lactase—An Economically Beneficial Way to Obtain Lactose-Free Milk at Low Temperature

Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 527
Author(s):  
Katarzyna Czyzewska ◽  
Anna Trusek
Keyword(s):  
Low Temperature ◽  
Storage Temperature ◽  
Competitive Inhibition ◽  
Caloric Content ◽  
Substrate Diffusion ◽  
Galactose Inhibition ◽  
The Subject ◽  
And Storage ◽  
Food Processes ◽  
Hydrolysis Of

The current requirements of industrial biocatalysis are related to economically beneficial and environmentally friendly processes. Such a strategy engages low-temperature reactions. The presented approach is essential, especially in food processes, where temperature affects the quality and nutritional value foodstuffs. The subject of the study is the hydrolysis of lactose with the commercial lactase NOLA™ Fit 5500 (NOLA). The complete decomposition of lactose into two monosaccharides gives a sweeter product, recommended for lactose intolerant people and those controlling a product’s caloric content. The hydrolysis reaction was performed at 15 °C, which is related to milk transportation and storage temperature. The enzyme showed activity over the entire range of substrate concentrations (up to 55 g/L lactose). For reusability and easy isolation, the enzyme was encapsulated in a sodium alginate network. Its stability allows carrying out six cycles of the complete hydrolysis of lactose to monosaccharides, lasting from two to four hours. During the study, the kinetic description of native and encapsulated NOLA was conducted. As a result, the model of competitive galactose inhibition and glucose mixed influence (competitive inhibition and activation) was proposed. The capsule size does not influence the reaction rate; thus, the substrate diffusion into capsules can be omitted from the process description. The prepared 4 mm capsules are easy to separate between cycles, e.g., using sieves.

Effect of Domestic Processing and Cooking Methods on Total, HCl Extractable Iron and in vitro availability of Iron in Spinach and Amaranth Leaves

2002 ◽  
Vol 16 (2) ◽  
pp. 113-120 ◽  
Author(s):  
S.K. Yadav ◽  
S. Sehgal
Keyword(s):  
Iron Content ◽  
Dry Weight ◽  
Total Iron ◽  
Cooking Methods ◽  
In Vitro Availability ◽  
Domestic Processing ◽  
Polyethylene Bags ◽  
And Storage ◽  
Extractable Iron

Spinach ( Spinacia oleracia) and amaranth ( Amaranthus tricolor) leaves were stored in polyethylene bags and without packing for 24 and 48 hours in a refrigerator at 5°C and 30°C in polyethylene bags. The fresh leaves were also dried (oven and sun), blanched (5, 10 and 15 min) and cooked in an open pan and a pressure cooker. The processed leaves were analysed for total iron, its availability and antinutrient content. The iron content of these leaves varied from 26.54 to 34.14 mg/l00g, dry weight and its HCl-extractability and in vitro availability were 62.11–67.18% and 3.03–3.97% of total respectively. Drying and storage had no significant effect on total iron content, Hel-extractability and availability ( in vitro), while blanching and cooking resulted in significant improvement of iron availability, and a significant reduction in oxalic acid content, while only blanching significantly reduced phytic acid and polyphenol contents. Thus cooking and blanching are good ways to improve HCl-extractability and in vitro availability of iron.

scholarly journals Research on hydrogen generation from rapid hydrolysis of aluminum in sodium fluoride solution

2019 ◽  
Vol 118 ◽  
pp. 03048
Author(s):  
Changchun Li ◽  
Yuxin Wu
Keyword(s):  
Hydrogen Production ◽  
Kinetic Model ◽  
Sodium Fluoride ◽  
Hydrogen Generation ◽  
Hydrogen Yield ◽  
Shrinking Core Model ◽  
Fluoride Solution ◽  
Shrinking Core ◽  
Rapid Hydrolysis ◽  
Hydrolysis Of

Hydrogen generation from rapid hydrolysis of aluminum in sodium fluoride solution was investigated through a hydrolysis experiment. Rapid and instant hydrogen yield were observed using sodium fluoride as additive. The experimental results demonstrate that the increase of temperature and the amount of additives in a certain range will boost the hydrogen production. The amount of additives outside the range only has an effect on the rapid hydrolysis of the aluminum during the initial stage, but the total amount of hydrogen produced doesn’t increased significantly. Theoretical analysis of the effects of the mixing ratio and the temperature on the hydrogen production rates were performed using the shrinking core model and the kinetic model. The shrinking core model parameter a and k indicate the film change degree of porosity and thickness and the effect of time on the diffusion coefficient. the kinetic model is verified and the activation energy confirming hydrogen yield control by a molecular diffusion process. Correspondingly, mechanisms of Al corrosion in NaF solutions under low and high alkalinity were proposed, respectively.

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