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.

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.

Mutant atténué nitrosoguanidine-induit dans la gangrène gazeuse à Clostridium perfringens type A

1975 ◽  
Vol 21 (8) ◽  
pp. 1259-1269 ◽  
Author(s):  
Jean-Rock Lapointe ◽  
Victorien Fredette
Keyword(s):  
Clostridium Perfringens ◽  
Wild Strain ◽  
Type A ◽  
Gas Gangrene ◽  
Classical Type ◽  
Logarithmic Growth Phase ◽  
Viable Bacteria ◽  
Low Levels ◽  
First Time ◽  
Logarithmic Growth

A fully virulent classical type A strain of Clostridium perfringens was treated during its logarithmic growth phase with 100 μg/ml of N-méthyl-N′-nitro-N-nitrosoguanidine, the bacteria being exposed to the mutagen for 30 min at 37 °C in a phosphate buffer adjusted to pH 6.2; after treatment the suspension was streaked on sheep blood agar plates, and colonies that showed an alteration in the theta-hemolysis pattern were selected for isolation. The virulence of two mutants, thus altered in their thêta-hemolysis, was studied. One, designated LNG 5, was still capable of killing most of the inoculated guinea pigs in less than 24 h with all the clinical, macroscopic, and bacteriological signs of gas gangrene; however, histological sections showed that tissue damage was not as marked as with the wild strain. On the contrary, the second mutant, labelled LNG 11, was completely avirulent as far as gas gangrene was concerned; indeed, the injection of fluid cultures containing 1 × 108-109/ml viable bacteria, was not followed by any clinical, bacteriological, or histological signs of gas gangrene. However, strain LNG 11 did give rise to a firm swelling of the inoculated thigh with a corresponding acute inflammatory response of the connective tissue, although the muscle fiber was unaltered. Eventually, this local reaction was followed by necrosis of the skin accompanied by an acute or subacute inflammation with fibroblastic proliferation. These superficial lesions healed spontaneously. They could not be reproduced with crude filtrate alone or with washed bacilli. Strain LNG 11 was therefore considered to be solely an attenuated strain since, although avirulent as far as gas gangrene is concerned, it is still capable of producing low levels of toxic material. This appears to be the first time that such a strain of C. perfringens type A has been obtained by nitrosoguanidine treatment.

Use of Pediococcus acidilactici to Control Listeria monocytogenes in Temperature-Abused Vacuum-Packaged Wieners

1992 ◽  
Vol 55 (2) ◽  
pp. 98-103 ◽  
Author(s):  
ALAN J. DEGNAN ◽  
AHMED E. YOUSEF ◽  
JOHN B. LUCHANSKY
Keyword(s):  
Listeria Monocytogenes ◽  
Bacteriocin Production ◽  
Logarithmic Phase ◽  
Refrigerated Storage ◽  
Pediococcus Acidilactici ◽  
Bacteriocin Activity ◽  
Cell Numbers ◽  
Late Logarithmic Phase ◽  
Logarithmic Growth ◽  
Produce Acid

Pediococcus acidilactici JBL1095 (pediocin AcH producer) and P. acidilactici LB42 (bacteriocin nonproducer) were evaluated for the production of antilisterial compounds in packages of all-beef wieners. Commercially processed, freshly manufactured, unpackaged wieners were surface inoculated (ca. 105 CFU/g) as follows: (i) untreated control; (ii) a three-strain (Scott A, V7, 101M) mixture of Listeria monocytogenes; (iii) strain JBL1095; (iv) L. monocytogenes and strain JBL1095; and (v) L. monocytogenes and strain LB42. Wieners were vacuum packaged and cell numbers, pH, and bacteriocin activity within packages were determined following storage at refrigeration (4°C) or abuse (25°C) temperatures for 72 and 8 d, respectively. L. monocytogenes and pediococci survived in packages held at 4°C, but pediococci did not produce acid or pediocin during refrigerated storage. At 25°C, total numbers of L. monocytogenes (treatment ii) increased 3.2 log10 CFU/g and the pH of the fluid (exudate) within packages increased from 5.5 to 5.6. In contrast, L. monocytogenes survived but did not grow in packages inoculated with strain LB42 (treatment v), and was inhibited (average reduction of 2.7 log10 CFU/g) in packages inoculated with strain JBL1095 (treatment iv) during storage at 25°C for 8 d. The pH of exudate in packages inoculated with strains JBL1095 (treatment iv) or LB42 (treatment v) showed a similar decline (ca. 5.5 to 4.6). The onset of bacteriocin production coincided with early-logarithmic growth of JBL1095 (treatment iv) and continued into the late logarithmic phase. These data suggest that bacteriocinogenic pediococci can be used to control L. monocytogenes in temperature-abused, cook/chili meats.

A Micrurgical Method for Preparation of Chromosomes for Electron Microscopy

1967 ◽  
Vol 25 ◽  
pp. 128-129
Author(s):  
Godfrey C. Hoskins
Keyword(s):  
Electron Microscopy ◽  
Mammalian Cells ◽  
Microscope Slide ◽  
Mitotic Apparatus ◽  
Logarithmic Growth Phase ◽  
Clear Area ◽  
Fluid Environment ◽  
A Cell ◽  
Logarithmic Growth

Mammalian cells on coverslips in vitro are used during logarithmic growth phase to obtain many cells in mitosis without the use of mitotic inhibitors.Two short lengths of glass tubing attached by beeswax to a standard microscope slide provide support for the coverslip. The coverslip is placed cell side down to form a chamber with open ends for admission of microneedles and for changing the fluid environment of the cells. This open ended chamber is then filled with a physiologic salt solution such as Hanks or a growth medium such as Eagles.Microneedles governed by deFonbrune micromanipulators are admitted through the open ends of the chamber. A cell in metaphase is located, picked up by microneedle, and carried to a clear area on the coverslip (Fig. 1). The second microneedle may hold the cell while the first is moved sidewise to create an incision in the cell membrane through which the mitotic apparatus may egress.

Morphological Characterization of Mycobacteriophage R1

1974 ◽  
Vol 32 ◽  
pp. 254-255
Author(s):  
B. L. Soloff ◽  
T. A. Rado
Keyword(s):  
Carbon Source ◽  
Stationary Phase ◽  
Growth Phase ◽  
Minimal Medium ◽  
Morphological Characterization ◽  
Logarithmic Growth Phase ◽  
Complete Lysis ◽  
Lysogenic Culture ◽  
Logarithmic Growth

Mycobacteriophage R1 was originally isolated from a lysogenic culture of M. butyricum. The virus was propagated on a leucine-requiring derivative of M. smegmatis, 607 leu−, isolated by nitrosoguanidine mutagenesis of typestrain ATCC 607. Growth was accomplished in a minimal medium containing glycerol and glucose as carbon source and enriched by the addition of 80 μg/ ml L-leucine. Bacteria in early logarithmic growth phase were infected with virus at a multiplicity of 5, and incubated with aeration for 8 hours. The partially lysed suspension was diluted 1:10 in growth medium and incubated for a further 8 hours. This permitted stationary phase cells to re-enter logarithmic growth and resulted in complete lysis of the culture.

Preparation and disinfection properties of graphene oxide/trichloroisocyanuric acid disinfectant

2021 ◽  
Author(s):  
li li jiang ◽  
Su Xu ◽  
Haitao Yu ◽  
Qi Cui ◽  
Rui Cao
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Minimum Inhibitory Concentration ◽  
Inhibitory Concentration ◽  
Kinetic Curve ◽  
X Ray ◽  
Bacterial Inhibition ◽  
E Coli ◽  
Blending Method ◽  
Trichloroisocyanuric Acid

Abstract In this study, graphene oxide (GO) was first prepared by the modified Hummer method. Then, the GO/trichloroisocyanuric acid (TCCA) composite was prepared by loading TCCA into GO with the blending method. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and atomic force microscopy were used to characterize the composite. The results showed that TCCA was successfully loaded on the surface of GO or intercalated among GO layers. Next, the antibacterial performance of the composite against Escherichia coli and Staphylococcus aureus was tested by the 96-well plate assay. A bactericidal kinetic curve, bacterial inhibition tests, and the mechanism of bacterial inhibition is discussed. The results showed that the minimum inhibitory concentration of the GO/TCCA composite (GO:TCCA ratio = 1:50) was 327.5 µg/mL against E. coli and 655 µg/mL against S. aureus. At the minimum inhibitory concentration, the inhibition rate of the GO/TCCA composite exceeded 99.46% against E. coli and 99.17% against S. aureus. The bactericidal kinetic curves indicate that the GO/TCCA composite has an excellent bactericidal effect against E. coli and S. aureus.

Regeneration of protoplasts in Saccharomyces

1972 ◽  
Vol 18 (11) ◽  
pp. 1773-1775 ◽  
Author(s):  
M. M. Shahin
Keyword(s):  
Growth Phase ◽  
Transition Phase ◽  
Protoplast Formation ◽  
Logarithmic Growth Phase ◽  
High Degree ◽  
Logarithmic Growth

Protoplasts prepared from cells of different stages within the logarithmic growth phase and from transition phase showed different degrees of colony-forming ability. The cells yielding higher frequency of protoplast formation also gave protoplast with a high degree of colony-forming ability.

scholarly journals OPTIMIZATION OF BACTERIOCIN PRODUCTION BY Lactococcus lactis ssp. lactis CN1.10a ORIGIN FROM RUSIPS

2014 ◽  
Vol 9 (3) ◽  
pp. 97
Author(s):  
Ninoek Indriati ◽  
Arifah Kusmarwati ◽  
Irma Hermana
Keyword(s):  
Lactococcus Lactis ◽  
Growth Curve ◽  
Growth Conditions ◽  
Relative Activity ◽  
Bacteriocin Production ◽  
Bacteriocin Activity ◽  
Carbohydrate Source ◽  
Fermented Fish ◽  
Producer Cell

Previous study of bacteriocin production on laboratory scale (100 mL) that used MRS broth medium produced unstable activity of bacteriocin. Therefore, this study aims to determine the optimum growth conditions and media for production of bacteriocin. Bacteria used in this research was a lactic acid bacteria (LAB) Lactococcus lactis ssp. lactis CN1.10a  isolated from rusip, a traditional Bangkanese fermented fish product.The bacteria was first cultivated for subsequent use of bacteriocins production on intermediate scale (2L). Followed by the optimization of temperature, pH and medium for the bacteriocin production, determination of cell growth curve, bacteriocin production curve, bacteriocin activity on that scale, and also stability of bacteriocin during storage.The results showed that the optimum temperature and pH for the growth of producer cell were 28°C and pH 6. The greatest activity of bacteriocin was produced on CM medium (1% sucrose, 0,45% peptone, 1% yeast extract, 2,84% KH2PO4, 0,2% NaCl and 0,02% MgSO4.7H20) in addition of sucrose as carbohydrate source. Based on the growth curve performedon CM medium with KH2PO4, the L. Lactis ssp lactis CN1.10a was relatively stable up to 48 hours. Bacteriocin produced by the cell was  8000 AU/mlat24th hour.Bacteriocin  was relatively stable when stored at -20°C for 1month with a relative activity of 69,4%.

scholarly journals A and alpha supernatant pretreatment of Saccharomyces cerevisiae cells affects both the kinetics and efficiency of mating.

1982 ◽  
Vol 2 (8) ◽  
pp. 897-903 ◽  
Author(s):  
E P Sena
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Fusion ◽  
Large Scale ◽  
Culture Supernatant ◽  
Treatment Procedure ◽  
Logarithmic Growth Phase ◽  
Future Studies ◽  
Mating Efficiency ◽  
Potential Applications ◽  
Logarithmic Growth

The effects of culture supernatant treatment on subsequent matings between pretreated a and alpha Saccharomyces cerevisiae cells were studied. For each experiment, pairs of a and alpha [rho+] or [rho- rho0] cells in the logarithmic growth phase in defined minimal medium were pretreated for a total of 15 min (by exchanging their cell-free supernatants or by mixing samples of a and alpha cell cultures) and then mated in defined minimal (YNB) or enriched (YEP) liquid medium. All pretreated cells, regardless of treatment procedure, initiated cell fusion 15 to 35 min faster than did their nontreated counterparts. In all cases, pretreated cells mated 8 to 20% more efficiently than did nonpretreated ones. Regardless of the strains, the hierarchy of mating efficiency was always treated YEP greater than untreated YEP greater than treated YNB greater than untreated YNB. The cell fusion kinetics in alpha [rho+] X a [rho-] crosses were most affected by pretreatment (delta 30 to 35 min), whereas [rho+] X [rho+] crosses were least affected (delta 15 min). These results are discussed in relation to the functions known for a and alpha pheromones. The successful pretreatment regimes were used to design new rapid and efficient techniques for mating YNB-grown log-phase cells in either YNB or YEP liquid media. These techniques can be used for small- or large-scale mating, and because of their inherent media flexibility, they have many potential applications to future studies on mating-specific or intrazygotic phenomena.

A and alpha supernatant pretreatment of Saccharomyces cerevisiae cells affects both the kinetics and efficiency of mating

1982 ◽  
Vol 2 (8) ◽  
pp. 897-903
Author(s):  
E P Sena
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Fusion ◽  
Large Scale ◽  
Culture Supernatant ◽  
Treatment Procedure ◽  
Logarithmic Growth Phase ◽  
Future Studies ◽  
Mating Efficiency ◽  
Potential Applications ◽  
Logarithmic Growth

The effects of culture supernatant treatment on subsequent matings between pretreated a and alpha Saccharomyces cerevisiae cells were studied. For each experiment, pairs of a and alpha [rho+] or [rho- rho0] cells in the logarithmic growth phase in defined minimal medium were pretreated for a total of 15 min (by exchanging their cell-free supernatants or by mixing samples of a and alpha cell cultures) and then mated in defined minimal (YNB) or enriched (YEP) liquid medium. All pretreated cells, regardless of treatment procedure, initiated cell fusion 15 to 35 min faster than did their nontreated counterparts. In all cases, pretreated cells mated 8 to 20% more efficiently than did nonpretreated ones. Regardless of the strains, the hierarchy of mating efficiency was always treated YEP greater than untreated YEP greater than treated YNB greater than untreated YNB. The cell fusion kinetics in alpha [rho+] X a [rho-] crosses were most affected by pretreatment (delta 30 to 35 min), whereas [rho+] X [rho+] crosses were least affected (delta 15 min). These results are discussed in relation to the functions known for a and alpha pheromones. The successful pretreatment regimes were used to design new rapid and efficient techniques for mating YNB-grown log-phase cells in either YNB or YEP liquid media. These techniques can be used for small- or large-scale mating, and because of their inherent media flexibility, they have many potential applications to future studies on mating-specific or intrazygotic phenomena.

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