Influence of Temperature of Incubation on Staphylococcus aureus Growth and Enterotoxin Production in Homemade Mayonnaise

1990 ◽  
Vol 53 (5) ◽  
pp. 386-390 ◽  
Author(s):  
ESPERANZA GÓMEZ-LUCÍA ◽  
JOAQUÍN GOYACHE ◽  
JOSÉ A. ORDEN ◽  
ANA DOMÉNECH ◽  
F. JAVIER HERNÁNDEZ ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Room Temperature ◽  
The Other ◽  
Influence Of Temperature ◽  
Enterotoxin Production

Homemade mayonnaise, in which pH had been adjusted to a range between 5.0 and 5.8 by the addition of vinegar, was inoculated with eight Staphylococcus aureus strains known to be enterotoxigenic. They were incubated for a maximum of 7 days at 22, 28, 37, and 44°C. Periodically, staphylococcal growth and pH were determined. Mayonnaise samples were examined on d 7 for the presence of enterotoxins A, B, C, and D. Staphylococcal growth was higher at 22°C (average log10 7.21 cfu/g), than at the other temperatures tested (log10 7.15, 6.77, and 5.93 cfu/g, respectively for 28, 37, and 44°C), suggesting a better growth in mayonnaise at low room temperature. Enterotoxin synthesis took place mainly at 28°C, as 33.3% of the total enterotoxins produced were detected at this temperature. However, some strains synthesized high amounts of enterotoxin even at 22°C.

scholarly journals Recent Observations on the Mechanical Properties of Polymer Networks

1971 ◽  
Vol 44 (5) ◽  
pp. 1256-1272 ◽  
Author(s):  
P. Thirion ◽  
R. Chasset
Keyword(s):  
Crosslink Density ◽  
Room Temperature ◽  
Dynamic Properties ◽  
Polymer Networks ◽  
The Other ◽  
Dilution Ratio ◽  
Chain Entanglement ◽  
Influence Of Temperature ◽  
Terminal Zone ◽  
Crosslinking Agents

Abstract The influence of temperature, elongation, swelling or dilution ratio, crosslink density, nature of the polymers, and crosslinking agents on the dynamic properties, creep and relaxation of polymer networks is surveyed in the terminal region of the spectrum. Whereas the deformation does not change the relaxation kinetics in large ranges of extension, the crosslink density acts as a reduced variable apparently accelerating uniformly the viscoelastic processes beyond the glass transition. The other possible reductions ‘time-temperature’ and ‘time—swelling’ do not necessarily seem related to the variations of free volume. From the viewpoint of the explanation of the relaxation mechanisms in the terminal zone, the fact that the equilibrium of loosely crosslinked elastomers would only virtually be reached after several years at room temperature seem in better agreement with chain entanglement effects, either trapped or not by the permanent network, than with the dissociation of secondary linkages.

Cytochemical Studies of Cell Wall Biosynthesis in Staphylococcus Aureus

1972 ◽  
Vol 30 ◽  
pp. 328-329
Author(s):  
Masaatsu Koike ◽  
Koichi Nakashima ◽  
Kyoko Iida
Keyword(s):  
Staphylococcus Aureus ◽  
Periodate Oxidation ◽  
Early Time ◽  
The Other ◽  
Penicillin G ◽  
Cell Wall Biosynthesis ◽  
Septal Wall ◽  
Peptidoglycan Biosynthesis ◽  
Gram Positive Bacteria ◽  
Cross Linkage

Penicillin exerts the activity to inhibit the peptide cross linkage between each polysaccharide backbone at the final stage of wall-peptidoglycan biosynthesis of bacteria. Morphologically, alterations of the septal wall and mesosome in gram-positive bacteria, which were occurred in early time after treatment with penicillin, have been observed. In this experiment, these alterations were cytochemically investigated by means of silver-methenamine staining after periodate oxidation, which is applied for detection of localization of wall mucopolysaccharide.Staphylococcus aureus strain 209P treated with 100 u/ml of penicillin G was divided into two aliquotes. One was fixed by Kellenberger-Ryter's OSO4 fixative at 30, 60 and 120 min after addition of the antibiotic, dehydrated through alcohol series, and embedded in Epon 812 (Specimen A). The other was fixed by 21 glutaraldehyde, dehydrated through glycolmethacrylate series and embedded in glycolmethacrylate mixture, according to Bernhard's method (Specimen B).

Electron microscope studies of the plastic deformation of ternary alloys based on GaAs

1990 ◽  
Vol 48 (4) ◽  
pp. 1120-1120
Author(s):  
R. Haswell ◽  
U. Bangert ◽  
P. Charsley
Keyword(s):  
Plastic Deformation ◽  
Electron Microscope ◽  
Room Temperature ◽  
Stacking Faults ◽  
The Other ◽  
Ternary Alloys ◽  
Dislocation Mobility ◽  
Semiconducting Materials ◽  
Micro Indentation

A knowledge of the behaviour of dislocations in semiconducting materials is essential to the understanding of devices which use them . This work is concerned with dislocations in alloys related to the semiconductor GaAs . Previous work on GaAs has shown that microtwinning occurs on one of the <110> rosette arms after indentation in preference to the other . We have shown that the effect of replacing some of the Ga atoms by Al results in microtwinning in both of the rosette arms.In the work to be reported dislocations in specimens of different compositions of Gax Al(1-x) As and Gax In(1-x) As have been studied by using micro indentation on a (001) face at room temperature . A range of electron microscope techniques have been used to investigate the type of dislocations and stacking faults/microtwins in the rosette arms , which are parallel to the [110] and [10] , as a function of composition for both alloys . Under certain conditions microtwinning occurs in both directions . This will be discussed in terms of the dislocation mobility.

Antibacterial Activity of Thujaoccidentalis,ThujaorientalisandChamaecyparisobtusa

2017 ◽  
Vol 8 (03) ◽  
Author(s):  
Kyoung- Sun Seo ◽  
Seong Woo Jin ◽  
Seongkyu Choi ◽  
Kyeong Won Yun
Keyword(s):  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Antibacterial Agent ◽  
Methanol Extract ◽  
The Other ◽  
Diffusion Method ◽  
E Coli ◽  
Agar Diffusion ◽  
Agar Diffusion Method ◽  
Crude Methanol Extract

The antibacterial activity of three Cupressaceae plants (Thujaoccidentalis,ThujaorientalisandChamaecyparisobtusa) was tested against three bacteria using the agar diffusion method. The ether and ethylacetate fraction of crude methanol extract from the three plants showed potent antibacterial activity against the tested microorganisms. The result showed that Staphylococcus aureus revealed the most sensitivity among the tested bacteria. Thujaoccidentalisether fraction and Thujaorientalis hexane fraction exhibited the highest antibacterial activity against Staphylococcus aureus. E. coli was shown the highest MIC values compared to the other two tested bacteria, which indicates the lowest antibacterial activity against the bacterium. This study promises an interesting future for designing a potentially active antibacterial agent from the three Cupressaceae plants.

HAYNES STELLITE ALLOY No. 98M2

Alloy Digest ◽  
1960 ◽  
Vol 9 (7) ◽  
Keyword(s):  
Fracture Toughness ◽  
Compressive Strength ◽  
Physical Properties ◽  
Room Temperature ◽  
Base Alloy ◽  
Heat Treating ◽  
The Other ◽  
Stellite Alloy ◽  
Cobalt Base Alloy ◽  
Cobalt Base

Abstract HAYNES STELLITE 98M2 Alloy is a cobalt-base alloy having higher compressive strength and higher hardness than all the other cobalt-base alloys at room temperature and in the red heat range. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive strength as well as fracture toughness. It also includes information on heat treating, machining, and joining. Filing Code: Co-22. Producer or source: Haynes Stellite Company.

The Reactivity of Different Active Forms of Sodium Carbonate with Respect to Sulfur Dioxide

1992 ◽  
Vol 57 (11) ◽  
pp. 2302-2308
Author(s):  
Karel Mocek ◽  
Erich Lippert ◽  
Emerich Erdös
Keyword(s):  
Thermal Decomposition ◽  
Liquid Phase ◽  
Sulfur Dioxide ◽  
Specific Surface ◽  
Surface Area ◽  
Sodium Carbonate ◽  
Room Temperature ◽  
Active Form ◽  
The Other ◽  
Kinetics Of

The kinetics of the reaction of solid sodium carbonate with sulfur dioxide depends on the microstructure of the solid, which in turn is affected by the way and conditions of its preparation. The active form, analogous to that obtained by thermal decomposition of NaHCO3, emerges from the dehydration of Na2CO3 . 10 H2O in a vacuum or its weathering in air at room temperature. The two active forms are porous and have approximately the same specific surface area. Partial hydration of the active Na2CO3 in air at room temperature followed by thermal dehydration does not bring about a significant decrease in reactivity. On the other hand, if the preparation of anhydrous Na2CO3 involves, partly or completely, the liquid phase, the reactivity of the product is substantially lower.

Effect of tea tree oil on Staphylococcus aureus growth and enterotoxin production

Food Control ◽  
2016 ◽  
Vol 62 ◽  
pp. 257-263 ◽  
Author(s):  
Ce Shi ◽  
Xingchen Zhao ◽  
Haiyang Yan ◽  
Rizeng Meng ◽  
Yan Zhang ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Tea Tree Oil ◽  
Tea Tree ◽  
Enterotoxin Production

scholarly journals Synthesis of spiro[dihydropyridine-oxindoles] via three-component reaction of arylamine, isatin and cyclopentane-1,3-dione

2013 ◽  
Vol 9 ◽  
pp. 8-14 ◽  
Author(s):  
Yan Sun ◽  
Jing Sun ◽  
Chao-Guo Yan
Keyword(s):  
Acetic Acid ◽  
Reaction Mechanism ◽  
Room Temperature ◽  
The Other ◽  
Other Hand ◽  
Three Component Reaction ◽  
High Yields

A fast and convenient protocol for the synthesis of novel spiro[dihydropyridine-oxindole] derivatives in satisfactory yields was developed by the three-component reactions of arylamine, isatin and cyclopentane-1,3-dione in acetic acid at room temperature. On the other hand the condensation of isatin with two equivalents of cyclopentane-1,3-dione gave 3,3-bis(2-hydroxy-5-oxo-cyclopent-1-enyl)oxindole in high yields. The reaction mechanism and substrate scope of this novel reaction is briefly discussed.

On the Chemistry of Tetrabenzyl Thiuram Disulfide and Tetramethyl Thiuram Disulfide with Bis (Triethoxysilylpropyl) Tetrasulfide in Silica Compounds

2003 ◽  
Vol 76 (4) ◽  
pp. 876-891 ◽  
Author(s):  
R. N. Datta ◽  
A. G. Talma ◽  
S. Datta ◽  
P. G. J. Nieuwenhuis ◽  
W. J. Nijenhuis ◽  
...  
Keyword(s):  
High Performance ◽  
Room Temperature ◽  
Succinic Anhydride ◽  
Dynamic Properties ◽  
The Other ◽  
Resonance Spectroscopy ◽  
Reaction Products ◽  
Negative Effect ◽  
Higher Temperature ◽  
Analytical Tools

Abstract The use of thiurams such as Tetramethyl thiuram disulfide (TMTD) or Tetrabenzyl thiuram disulfide (TBzTD) has been explored to achieve higher cure efficiency. The studies suggest that a clear difference exists between the effect of TMTD versus TBzTD. TMTD reacts with Bis (triethoxysilylpropyl) tetrasulfide (TESPT) and this reaction can take place even at room temperature. On the other hand, the reaction of TBzTD with TESPT is slow and takes place only at higher temperature. High Performance Liquid Chromatography (HPLC) with mass (MS) detection, Nuclear Magnetic Resonance Spectroscopy (NMR) and other analytical tools have been used to understand the differences between the reaction of TMTD and TESPT versus TBzTD and TESPT. The reaction products originating from these reactions are also identified. These studies indicate that unlike TMTD, TBzTD improves the cure efficiency allowing faster cure without significant effect on processing characteristics as well as dynamic properties. The loading of TESPT is reduced in a typical Green tire compound and the negative effect on viscosity is repaired by addition of anhydrides, such as succinic anhydride, maleic anhydride, etc.

scholarly journals The linkage of sugar phosphate polymer to peptidoglycan in walls of Micrococcus sp. 2102

1978 ◽  
Vol 169 (2) ◽  
pp. 329-336 ◽  
Author(s):  
J Heptinstall ◽  
J Coley ◽  
P J Ward ◽  
A R Archibald ◽  
J Baddiley
Keyword(s):  
Staphylococcus Aureus ◽  
Alkaline Hydrolysis ◽  
The Other ◽  
Muramic Acid ◽  
Sugar Phosphate ◽  
Glycerol Phosphate ◽  
Homogeneous Product ◽  
A Chain

1. Protein-free walls of Micrococcus sp. 2102 contain peptidoglycan, poly-(N-acetylglucosamine 1-phosphate) and small amounts of glycerol phosphate. 2. After destruction of the poly-(N-acetylglucosamine 1-phosphate) with periodate, the glycerol phosphate remains attached to the wall, but can be removed by controlled alkaline hydrolysis. The homogeneous product comprises a chain of three glycerol phosphates and an additional phosphate residue. 3. The poly-(N-acetylglucosamine 1-phosphate) is attached through its terminal phosphate to one end of the tri(glycerol phosphate). 4. The other end of the glycerol phosphate trimer is attached through its terminal phosphate to the 3-or 4-position of an N-acetylglucosamine. It is concluded that the sequence of residues in the sugar 1-phosphate polymer-peptidoglycan complex is: (N-acetylglucosamine 1-phosphate)24-(glycerol phosphate)3-N-acetylglucosamine 1-phosphate-muramic acid (in peptidoglycan). Thus in this organism the phosphorylated wall polymer is attached to the peptidoglycan of the wall through a linkage unit comprising a chain of three glycerol phosphate residues and an N-acetylglucosamine 1-phosphate, similar to or identical with the linkage unit in Staphylococcus aureus H.

Sign in / Sign up

Export Citation Format

Share Document