Bacteriocins of Clostridium perfringens. 2. Studies on mode of action

1971 ◽  
Vol 17 (11) ◽  
pp. 1435-1442 ◽  
Author(s):  
D. E. Mahony ◽  
M. E. Butler ◽  
R. G. Lewis
Keyword(s):  
Cell Wall ◽  
Clostridium Perfringens ◽  
Mode Of Action ◽  
Radioactive Isotope ◽  
Indicator Strain ◽  
Subsequent Treatment ◽  
The Other ◽  
Indicator Bacteria ◽  
Bacteriocin Activity ◽  
Specific Bacteriophage

The effects of bacteriocin 28 on sensitive strains of Clostridium perfringens are further described. Two indicator strains were chosen for detailed study. These strains, when treated with bacteriocin, were induced to produce spherical forms devoid of cell wall. The efficiency of conversion to spheroplasts in one strain was greatly enhanced when the organism was grown in 0.3 M sucrose broth. Sucrose, itself, was capable of inducing spheroplast formation in the other strain in the absence of bacteriocin, this being the only indicator strain observed to behave in this manner.Bacteriocin could not induce spheroplast formation when indicator bacteria were either heavily irradiated with ultraviolet light or when the culture was vigorously aerated, suggesting that metabolically active cells were required for the conversion phenomenon. When bacteriocin-treated cultures were plated on sucrose containing media, L-form colonies developed.Spheroplasts induced by bacteriocin could no longer adsorb a specific bacteriophage, which suggested that there might be a loss of cell wall receptors. Although the bacteriocin is sensitive to trypsin, it was impossible to reverse bacteriocin activity on sensitive cells by subsequent treatment with trypsin. Radioactive isotope incorporation revealed that cells treated with bacteriocin continued to synthesize DNA, RNA, and protein.

Bacteriocins of Clostridium perfringens. 1. Isolation and preliminary studies

1971 ◽  
Vol 17 (1) ◽  
pp. 1-6 ◽  
Author(s):  
D. E. Mahony ◽  
M. E. Butler
Keyword(s):  
Electron Microscopy ◽  
Clostridium Perfringens ◽  
Indicator Strain ◽  
Bacteriocin Production ◽  
Bacteriocin Activity ◽  
Logarithmic Growth Phase ◽  
Bacterial Inhibition ◽  
Relative Response ◽  
Bacterial Sensitivity ◽  
Logarithmic Growth

Thirty-three strains of Clostridium perfringens were screened for bacteriocin production. Four bacteriocin-producing strains were detected by plating the supernatant fluids of these cultures on all available strains of C. perfringens seeded in semisolid agar and noting zones of bacterial inhibition after subsequent incubation. The spectrum of sensitive strains differed for each bacteriocin as did the degree of bacterial sensitivity to each bacteriocin.One bacteriocin and one indicator strain were chosen for further study. This bacteriocin, which was spontaneously produced during the logarithmic growth phase of the bacteriocinogenic strain, was not inducible with ultraviolet light but was sensitive to heat and trypsin. Adsorption of bacteriocin to the indicator strain was not detected and electron microscopy did not reveal any particulate substance associated with bacteriocin activity. The degree of bacterial inhibition was dependent on the titer of the bacteriocin used, and the age of the indicator culture appeared to influence its relative response to bacteriocin treatment.

scholarly journals The newly synthesized thiazole derivatives as potential antifungal compounds against Candida albicans

2021 ◽  
Author(s):  
Anna Biernasiuk ◽  
Anna Berecka-Rycerz ◽  
Anna Gumieniczek ◽  
Maria Malm ◽  
Krzysztof Z. Łączkowski ◽  
...  
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Antifungal Activity ◽  
Cell Membrane ◽  
Mode Of Action ◽  
Thiazole Derivatives ◽  
Fungal Cell ◽  
Erythrocyte Lysis ◽  
Low Cytotoxicity ◽  
High Antifungal Activity

Abstract Recently, the occurrence of candidiasis has increased dramatically, especially in immunocompromised patients. Additionally, their treatment is often ineffective due to the resistance of yeasts to antimycotics. Therefore, there is a need to search for new antifungals. A series of nine newly synthesized thiazole derivatives containing the cyclopropane system, showing promising activity against Candida spp., has been further investigated. We decided to verify their antifungal activity towards clinical Candida albicans isolated from the oral cavity of patients with hematological malignancies and investigate the mode of action on fungal cell, the effect of combination with the selected antimycotics, toxicity to erythrocytes, and lipophilicity. These studies were performed by the broth microdilution method, test with sorbitol and ergosterol, checkerboard technique, erythrocyte lysis assay, and reversed phase thin-layer chromatography, respectively. All derivatives showed very strong activity (similar and even higher than nystatin) against all C. albicans isolates with minimal inhibitory concentration (MIC) = 0.008–7.81 µg/mL Their mechanism of action may be related to action within the fungal cell wall structure and/or within the cell membrane. The interactions between the derivatives and the selected antimycotics (nystatin, chlorhexidine, and thymol) showed additive effect only in the case of combination some of them and thymol. The erythrocyte lysis assay confirmed the low cytotoxicity of these compounds as compared to nystatin. The high lipophilicity of the derivatives was related with their high antifungal activity. The present studies confirm that the studied thiazole derivatives containing the cyclopropane system appear to be a very promising group of compounds in treatment of infections caused by C. albicans. However, this requires further studies in vivo. Key points • The newly thiazoles showed high antifungal activity and some of them — additive effect in combination with thymol. • Their mode of action may be related with the influence on the structure of the fungal cell wall and/or the cell membrane. • The low cytotoxicity against erythrocytes and high lipophilicity of these derivatives are their additional good properties. Graphical abstract

scholarly journals A Putative Amidase Endolysin Encoded by Clostridium perfringens St13 Exhibits Specific Lytic Activity and Synergizes with the Muramidase Endolysin Psm

Antibiotics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 245
Author(s):  
Hiroshi Sekiya ◽  
Maho Okada ◽  
Eiji Tamai ◽  
Toshi Shimamoto ◽  
Tadashi Shimamoto ◽  
...  
Keyword(s):  
Cell Wall ◽  
Clostridium Perfringens ◽  
Antimicrobial Agents ◽  
Catalytic Domain ◽  
Food Poisoning ◽  
Binding Activity ◽  
Lytic Activity ◽  
Intestinal Bacterium ◽  
Terminal Domain ◽  
Cell Wall Binding

Clostridium perfringens is an often-harmful intestinal bacterium that causes various diseases ranging from food poisoning to life-threatening fulminant disease. Potential treatments include phage-derived endolysins, a promising family of alternative antimicrobial agents. We surveyed the genome of the C. perfringens st13 strain and identified an endolysin gene, psa, in the phage remnant region. Psa has an N-terminal catalytic domain that is homologous to the amidase_2 domain, and a C-terminal domain of unknown function. psa and gene derivatives encoding various Psa subdomains were cloned and expressed in Escherichia coli as N-terminal histidine-tagged proteins. Purified His-tagged full-length Psa protein (Psa-his) showed C. perfringens-specific lytic activity in turbidity reduction assays. In addition, we demonstrated that the uncharacterized C-terminal domain has cell wall-binding activity. Furthermore, cell wall-binding measurements showed that Psa binding was highly specific to C. perfringens. These results indicated that Psa is an amidase endolysin that specifically lyses C. perfringens; the enzyme’s specificity is highly dependent on the binding of the C-terminal domain. Moreover, Psa was shown to have a synergistic effect with another C. perfringens-specific endolysin, Psm, which is a muramidase that cleaves peptidoglycan at a site distinct from that targeted by Psa. The combination of Psa and Psm may be effective in the treatment and prevention of C. perfringens infections.

The Mode of Action of Disulfide Accelerators of Vulcanization

1937 ◽  
Vol 10 (1) ◽  
pp. 158-163
Author(s):  
W. Langenbeck ◽  
H. C. Rhiem
Keyword(s):  
Organic Compounds ◽  
Mode Of Action ◽  
Common Knowledge ◽  
Inorganic Compounds ◽  
Technical Problem ◽  
The Other ◽  
Rubber Industry ◽  
Organic Catalysis ◽  
Catalytic Power ◽  
Organic Catalysts

Abstract The catalytic power of organic compounds in general has up to the present time been studied much less extensively than that of inorganic compounds. For about the last ten years, however, the first author has, in collaboration with a number of his students, attempted to fill this gap, though so far efforts have been confined to explaining the mode of action of natural enzymes by means of comparative experiments with organic catalysts. As a result of this work, a theory based on experimental facts has been developed to explain in a satisfactory way the action of enzymes. The other phase of organic catalysis is, strictly speaking, a technical problem. Why for instance should it not be practicable to utilize organic catalysts more extensively than heretofore in industry? If this problem is to be attacked, it seems reasonable to start with the particular industry which already uses organic catalysts to the greatest extent. This is, of course, the rubber industry. The important accomplishments of the chemical industry with respect to the development of vulcanization accelerators is already common knowledge, and the important task at present is not simply to increase the great number of accelerators already known. A problem of more practical value would seem to be to study the mechanism of the acceleration of vulcanization, about which relatively little has been known heretofore.

scholarly journals Factors Contributing to Heat Resistance of Clostridium perfringens Endospores

2008 ◽  
Vol 74 (11) ◽  
pp. 3328-3335 ◽  
Author(s):  
Benjamin Orsburn ◽  
Stephen B. Melville ◽  
David L. Popham
Keyword(s):  
Cell Wall ◽  
Heat Resistance ◽  
Clostridium Perfringens ◽  
Food Poisoning ◽  
High Heat ◽  
Relative Importance ◽  
High Heat Resistance ◽  
Factors Affecting ◽  
Cooking Process ◽  
Determining Factors

ABSTRACT The endospores formed by strains of type A Clostridium perfringens that produce the C. perfringens enterotoxin (CPE) are known to be more resistant to heat and cold than strains that do not produce this toxin. The high heat resistance of these spores allows them to survive the cooking process, leading to a large number of food-poisoning cases each year. The relative importance of factors contributing to the establishment of heat resistance in this species is currently unknown. The present study examines the spores formed by both CPE+ and CPE− strains for factors known to affect heat resistance in other species. We have found that the concentrations of DPA and metal ions, the size of the spore core, and the protoplast-to-sporoplast ratio are determining factors affecting heat resistance in these strains. While the overall thickness of the spore peptidoglycan was found to be consistent in all strains, the relative amounts of cortex and germ cell wall peptidoglycan also appear to play a role in the heat resistance of these strains.

The Structure of Sycamore Callus Cells During Division in a Partially Synchronized Suspension Culture

1970 ◽  
Vol 6 (2) ◽  
pp. 299-321
Author(s):  
K. ROBERTS ◽  
D. H. NORTHCOTE
Keyword(s):  
Cell Wall ◽  
Electron Microscope ◽  
Cell Plate ◽  
Optical Microscope ◽  
The Other ◽  
Active Movement ◽  
Developmental Sequence ◽  
Golgi Bodies ◽  
Dividing Cells ◽  
Peripheral Cytoplasm

Sycamore suspension callus cells have been partially synchronized to give a culture with a mitotic index of 15%. Living dividing cells of the culture have been examined with Nomarski differential interference optics and a comparable study made on fixed cells with the electron microscope. An organized band of reticulate cytoplasm partially encircles the nucleus at mitosis. The cell divides by the formation of a phragmosome which grows across the large vacuole; this allows the organization of the cytoplasm which forms the cell plate to be examined separately from the more general cytoplasm of the cell. The cell plate grows from one side of the cell to the other and down its length a complete developmental sequence can be seen. The Golgi bodies and the endoplasmic reticulum are probably involved in the formation of material for the construction of the cell plate and young cell wall. Microfibrils are formed within the plate in the more mature regions, while material contained within vesicles is incorporated at the young growing edge. At the edge of the plate microtubules are found and these correspond to the fibrillar appearance of the phragmoplast seen with the optical microscope. In the living cell an active movement of organelles along the peripheral cytoplasm can be seen and with fixed cells viewed with the electron microscope microtubules are often found adjacent to the plasmalemma and lying close to mitochondria, crystal-containing bodies and plastids. The appearance of crystal-containing bodies and plastids containing phytoferritin is described.

scholarly journals Insights into the Mode of Action of Chitosan as an Antibacterial Compound

2008 ◽  
Vol 74 (12) ◽  
pp. 3764-3773 ◽  
Author(s):  
Dina Raafat ◽  
Kristine von Bargen ◽  
Albert Haas ◽  
Hans-Georg Sahl
Keyword(s):  
Antimicrobial Activity ◽  
Cell Wall ◽  
Cell Membrane ◽  
Mode Of Action ◽  
Membrane Lipids ◽  
Expression Profiles ◽  
Transcriptional Response ◽  
Response Analysis ◽  
Sequence Of Events ◽  
Wide Range

ABSTRACT Chitosan is a polysaccharide biopolymer that combines a unique set of versatile physicochemical and biological characteristics which allow for a wide range of applications. Although its antimicrobial activity is well documented, its mode of action has hitherto remained only vaguely defined. In this work we investigated the antimicrobial mode of action of chitosan using a combination of approaches, including in vitro assays, killing kinetics, cellular leakage measurements, membrane potential estimations, and electron microscopy, in addition to transcriptional response analysis. Chitosan, whose antimicrobial activity was influenced by several factors, exhibited a dose-dependent growth-inhibitory effect. A simultaneous permeabilization of the cell membrane to small cellular components, coupled to a significant membrane depolarization, was detected. A concomitant interference with cell wall biosynthesis was not observed. Chitosan treatment of Staphylococcus simulans 22 cells did not give rise to cell wall lysis; the cell membrane also remained intact. Analysis of transcriptional response data revealed that chitosan treatment leads to multiple changes in the expression profiles of Staphylococcus aureus SG511 genes involved in the regulation of stress and autolysis, as well as genes associated with energy metabolism. Finally, a possible mechanism for chitosan's activity is postulated. Although we contend that there might not be a single classical target that would explain chitosan's antimicrobial action, we speculate that binding of chitosan to teichoic acids, coupled with a potential extraction of membrane lipids (predominantly lipoteichoic acid) results in a sequence of events, ultimately leading to bacterial death.

scholarly journals Nukacin ISK-1, a Bacteriostatic Lantibiotic

2009 ◽  
Vol 53 (8) ◽  
pp. 3595-3598 ◽  
Author(s):  
Sikder M. Asaduzzaman ◽  
Jun-ichi Nagao ◽  
Hiroshi Iida ◽  
Takeshi Zendo ◽  
Jiro Nakayama ◽  
...  
Keyword(s):  
Cell Wall ◽  
Membrane Potential ◽  
Bacterial Strain ◽  
Mode Of Action ◽  
Membrane Depolarization ◽  
Wall Width ◽  
Cytoplasmic Content ◽  
Remarkable Reduction

ABSTRACT We determined the mode of action of nukacin ISK-1. It did not cause membrane potential dissipation or the efflux of ATP or K+ ions from the cells of a sensitive bacterial strain; however, it blocked the membrane depolarization activity of nisin. Nukacin ISK-1-treated cells had single arrangements of cells without the formation of a complete septum. A remarkable reduction in cell wall width was also observed, but cytoplasmic content was unaffected. We concluded that nukacin ISK-1 is bacteriostatic.

scholarly journals Uptake and Metabolism of Tritiated 17ß-Oestradiol and Oestrone by Rabbit Uterine Tissue in vitro

1974 ◽  
Vol 27 (2) ◽  
pp. 137 ◽  
Author(s):  
RG Gabb ◽  
GM Stone
Keyword(s):  
Nuclear Receptor ◽  
Mode Of Action ◽  
Nuclear Extract ◽  
Lower Proportion ◽  
The Other ◽  
Uterine Tissue ◽  
Uptake And Metabolism

To determine whether the established capability of rabbit uterine tissue to interconvert 17 p-oestradiol and oestrone might have some effect on the mode of action of the oestrogens in this organ, the in vitro interconversion of [3H]-17p-oestradiol and [3H]oestrone by rabbit endometrial and myometrial tissue was investigated and the identity of radiometabolites in 'soluble, 'mitochondrial-microsomal' a'nd 'nuclear' preparations was studied. Both endometrial and myometrial tissue were found to be capable of oxidoreduction of the oestrogens, the equilibrium of the reaction favouring the reduction of oestrone. Irrespective of the tissue--steroid combination studied, the greater part of the radioactivity in all fractions was associated with 17p-oestradiol. The relative proportions of [3Hl-17p-oestradiol and [3H]oestrone varied between fractions, the nuclear preparation consistently showing a lower proportion of oestrone than the other fractions. Sephade<c fractionation of a 0'4M KCl 'nuclear extract' revealed that proportionately less oestrone than 17p-oestradiol was bound to the nuclear 'receptor'. These findings provide further evidence for 17p-oestradiol being the ovarian oestrogen which is active in the uterus, and suggest a role for uterine oxidoreduction of oestrogens in the control exercised over this organ by these steroids.

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