scholarly journals Effects of Epiphytic Enterobacteriaceae and Pseudomonads on the Growth of Listeria monocytogenes in Model Media

2001 ◽  
Vol 64 (5) ◽  
pp. 721-724 ◽  
Author(s):  
J. DEL CAMPO ◽  
F. CARLIN ◽  
C. NGUYEN-THE
Keyword(s):  
Amino Acids ◽  
Listeria Monocytogenes ◽  
Yeast Extract ◽  
Inhibitory Activity ◽  
Minimal Medium ◽  
Pseudomonas Chlororaphis ◽  
Enterobacter Agglomerans ◽  
Minimally Processed ◽  
Yeast Extract Medium ◽  
Extract Medium

Four Enterobacteriaceae (Enterobacter agglomerans and Rhanella aquatilis) and six pseudomonads (Pseudomonas fluorescens, Pseudomonas chlororaphis, Pseudomonas putida) isolated from minimally processed green endive were coinoculated at 10°C with Listeria monocytogenes in a minimal medium. Pseudomonads did not modify the growth of L. monocytogenes, whereas Enterobacteriaceae reduced its maximal population by 2 to 3 log CFU/ml. The same effect was observed in a diluted yeast extract medium supplemented with amino acids and glucose, in which L. monocytogenes grown alone reached 109 to 1010 CFU/ml. In the same diluted yeast extract medium, not supplemented with glucose and amino acids, the maximal population of L. monocytogenes in the presence of both Enterobacteriaceae and pseudomonads was only slightly reduced (less than 0.5 log CFU/ml). Culture filtrates of the Enterobacteriaceae had no inhibitory activity on L. monocytogenes. The effect of the Enterobacteriaceae on L. monocytogenes growth was presumably due to a competition for glucose and/or amino acids.

Isolation and identification of N2-fixing Pseudomonas associated with wetland rice

1983 ◽  
Vol 29 (8) ◽  
pp. 867-873 ◽  
Author(s):  
W. L. Barraquio ◽  
J. K. Ladha ◽  
I. Watanabe
Keyword(s):  
New Species ◽  
Yeast Extract ◽  
Heterotrophic Bacteria ◽  
Fluorescent Antibody ◽  
Wetland Rice ◽  
Isolation And Identification ◽  
Biochemical Characteristics ◽  
Yeast Extract Medium ◽  
Extract Medium ◽  
A New Species

Semisolid yeast extract medium amended with glucose and tryptic soy agar were used to isolate aerobically N2-fixing (C2H2-reducing) heterotrophic bacteria from the root of wetland rice. The isolates were identified as Pseudomonas by gel immunodiffusion and fluorescent antibody techniques in combination with their morphological, cultural, and biochemical characteristics. The N2-fixing H2-utilizing Pseudomonas described in this paper is a new species.

STRAIN IMPROVEMENT OF A FUNGUS PRODUCING CHITINASE BY A CHEMICAL MUTAGEN

INDIAN DRUGS ◽  
2013 ◽  
Vol 50 (11) ◽  
pp. 25-28
Author(s):  
K Narayanan ◽  
◽  
N.D. Chopade ◽  
V.M Subrahmanyam ◽  
J. Venkata Rao
Keyword(s):  
Protein Content ◽  
Ethidium Bromide ◽  
Yeast Extract ◽  
Wild Strain ◽  
Strain Improvement ◽  
Cost Effective ◽  
Specific Protein ◽  
Chemical Mutagen ◽  
Yeast Extract Medium ◽  
Extract Medium

Microbial chitinases are commercially exploited for their biocontrol properties and generation of useful products from chitinous waste. Availability of highly active chitinolytic enzymes is a major problem. The present study was carried out to improve chitinase production by Aspergillus terreus using a chemical mutagen, ethidium bromide. The organism was cultivated on lactose- yeast extract medium. The production medium consisting of chitin- yeast extract medium was seeded at 10% level. The wild strains were exposed to ethidium bromide in the concentration range 1.5- 6.0 µg/mL. Generally, all the mutated strains showed an improved chitinase yield compared to the control. Highest yield was observed with the strain exposed to 6 µg/mL of ethidium bromide. The yield was 25.03 % higher compared to the wild strain. The mutated strain was slimy in nature. Protein content of the mutated strain decreased by 11%. Ethidium bromide at a concentration of 1.5 µg/mL was considered optional, at which the strain was stable with increase of 21.80 % in enzyme activity and 4.41% increase in protein content. Increased enzyme yield with decreased non-specific protein could be useful in producing cost effective enzyme.

Media for Confirming Clostridium perfringens from Food and Feces

1978 ◽  
Vol 41 (8) ◽  
pp. 626-630 ◽  
Author(s):  
S. M. HARMON ◽  
D. A. KAUTTER
Keyword(s):  
Clostridium Perfringens ◽  
Yeast Extract ◽  
Nitrate Medium ◽  
Yeast Extract Medium ◽  
Selective Plating ◽  
Extract Medium

Several media recommended for confirming isolates of Clostridium perfringens from selective plating media were evaluated. Media for testing motility, reduction of nitrate to nitrite, fermentation of lactose, and liquefaction of gelatin were found to be the most useful. A modified motility-nitrate medium, developed during the study, and lactose-gelatin medium were the most satisfactory for doing these tests. Fermentation of salicin and raffinose in peptone-yeast extract medium was also useful for differentiating atypically reacting strains of C. perfringens from a variety of culturally similar clostridia.

Regulation by amino acids of α-amylase and endo-β(1→4)-glucanase induction in mycelial culture of the mushroom Termitomyces clypeatus

1990 ◽  
Vol 36 (9) ◽  
pp. 617-624 ◽  
Author(s):  
Saswati Sengupta ◽  
S. Sengupta
Keyword(s):  
Amino Acids ◽  
Yeast Extract ◽  
Enzyme Production ◽  
Late Phase ◽  
Synthetic Medium ◽  
Extracellular Enzyme ◽  
Mycelial Culture ◽  
Termitomyces Clypeatus ◽  
Yeast Extract Medium

Termitomyces clypeatus constitutively liberated amyloglucosidase; the liberation was not repressed by glucose. Growth of the mushroom in synthetic medium was slow with starch, and only amyloglucosidase was liberated. Yeast extract stimulated growth and enzyme production in starch medium, and α-amylase along with amyloglucosidase was detected extracellularly. The mushroom could not utilise cellulose or liberate endo-β(1 → 4)-glucanase even when inducer cellobiose or glucose was added to cellulose at different concentrations. Cellobiose alone also failed to induce any extracellular endo-β(1 → 4)-glucanase production. Yeast extract in both cellulose and cellobiose media supported liberation of endo-β(1 → 4)-glucanase. Lactose was found to be a poor inducer even in yeast extract medium. However, both α-amylase and endo-β(1 → 4)-glucanase were detected intracellularly at a basal level even when the enzymes were absent extracellularly under inducing and noninducing conditions. The intracellular enzymes were only freely liberated into the medium in the presence of yeast extract. It appeared that induction of α-amylase and endo-β(1 → 4)-glucanase was largely inhibited by the restricted liberation of the enzymes in absence of yeast extract. Of the yeast extract components, amino acids were the active ingredient mimicking the role of yeast extract in induction. Yeast extract was found to relieve catabolic inhibition observed at the late phase of enzyme production. It is proposed that catabolic inhibition might have a role in the enzyme liberation and that amino acids supported extracellular enzyme production by relieving this inhibition. Key words: mushroom, Termitomyces clypeatus, catabolic inhibition, polysaccharidase induction, amino acid.

Factors affecting the production of hydrogenase by Desulfovibrio desulfuricans

1980 ◽  
Vol 26 (10) ◽  
pp. 1209-1213 ◽  
Author(s):  
S. M. Martin ◽  
B. R. Glick ◽  
W. G. Martin
Keyword(s):  
Ammonium Sulfate ◽  
Yeast Extract ◽  
Desulfovibrio Desulfuricans ◽  
The Other ◽  
Hydrogenase Activity ◽  
Factors Affecting ◽  
Yeast Extract Medium ◽  
Extract Medium ◽  
Culture Development

An examination of conditions for the growth of Desulfovibrio desulfuricans, with the aim of optimizing hydrogenase production, is reported. An ammonium sulfate – lactate – yeast extract medium gave 5 to 10 times as much hydrogenase activity as a peptone – yeast extract medium. It made little if any difference whether the gas used for sparging was nitrogen, hydrogen, or a mixture thereof but increasing the rate of sparging and agitation did result in a slight decrease in activity. Control of pH during culture development was of little benefit to hydrogenase production. At least two hydrogenases were present in D. desulfuricans: one periplasmic, the other membrane bound.Desulfovibrio desulfuricans produced more hydrogenase than did either D. gigas and D. vulgaris.

scholarly journals Rhodotorula glutinis: STRAIN ENRICHMENT AND EVALUATION OF PHENYLALANINE AMMONIA LYASE

2007 ◽  
Vol 44 (1) ◽  
Author(s):  
M. Jason MacDonald ◽  
Godwin B. D'Cunha
Keyword(s):  
Nous Avons ◽  
Yeast Extract ◽  
Phenylalanine Ammonia Lyase ◽  
Rhodotorula Glutinis ◽  
Yeast Cells ◽  
Pal Activity ◽  
Yeast Extract Medium ◽  
Extract Medium ◽  
Phenylalanine Methyl Ester

2006 NSIS Honourable Mention, Undergraduate Student ResearchPrize Winning PaperThe enrichment of a Rhodotorula glufinis strain and the determination of itsphenylalanine ammonia lyase (E.C.4.3.1.5 - PAL) activity and attempts to measure peroxidase (E.C.1.11.1. 7) activity included conventional mycological procedures along with chemical and microscopic examination. Sabouraud dextrose medium was found to be the most suitable for cell growth, but cells grown on yeast-extract medium exhibited optimal enzyme activity. Growth and PAL activity were measured in yeast cells grown in yeast-extract broth medium for 24-27 h. The appearance of a reddish pink color associated with the yeast cells coincided with the appearance of appreciable PAL activity. The maximum PAL activity and biomass of yeast obtained in the yeast extract medium ranged from 33 to 35 unitslmg dry cells and 7.5 to 8.0 g dry cells/l, respectively. In addition to phenylalanine, Rhodatowla PAL also used phenylalanine methyl-ester as a substrate. No peroxidase activity was found in these R. glutinis cells.L'enrichissement de la souche de Rhodatarula glutinis et la detenmination de l'activite de la phenylalanine ammoniac-lyase (E.C.4.3.1.5 - PAL) chez cette souche, de meme que les tentatives de mesure de I'activite de la peroxydase (E.C.1 .11.1 .7), ont compris I'utilisation de procedures mycologiques traditionnelles ainsi que des examens microscopiques et chimiques. Nous avons constate que la gelose Sabouraud au dextrose est Ie meilleur milieu pour assurer la croissance cellulaire, mais que l'activite enzymatique est optimale dans les cellules cultivees sur un milieu a base d'extrait de levure. Nousavons mesure la croissance de cellulesde levure culliveesdans un bouillon a base d'extrait de levure pendant 24 a 27 heures et nous avons mesure I'activite de la PAL dans ces memes cellules. L'apparition d'une couleur rose rougeatre associee aux cellules de levure a coIncide avec Ie debut d'une periode d'activite notable de laPAL. L'activite maxima Ie de la PAL obtenue dans Ie milieu a base d'exlrait de levure a varie de 33 a 35 unites par mg de cellules seches, tandis que la biomasse de levure maximale obtenue dans Ie meme milieu a varie de 7,5 a 8,0 9 de cellules seches par litre. En plus de la phenylalanine, la PAlde Rhodotorula a utilise I'ester methylique de la phenylalanine comme substrat. Aucune activite de la peroxydase n'a ete observee dans ces cellules de R. glutinis.•

Production of Staphylococcal Enterotoxins A, D, and E by Sac Culture

1991 ◽  
Vol 54 (8) ◽  
pp. 650-652
Author(s):  
HELENA RODRIGUES LOPES ◽  
ALBA LUCIA SOLINO NOLETO ◽  
MERLIN S. BERGDOLL
Keyword(s):  
Optimum Condition ◽  
Yeast Extract ◽  
Brain Heart Infusion ◽  
Culture Method ◽  
Union Carbide ◽  
Staphylococcal Enterotoxins ◽  
Yeast Extract Medium ◽  
Shake Flasks ◽  
Extract Medium ◽  
Sausage Casing

The use of the sac culture method for production of relatively large amounts of enterotoxins A (SEA), D (SED), and E (SEE) for use in purification of the enterotoxins was investigated. One-hundred milliliters of medium per sac, made from Union Carbide sausage casing, with a shaking speed of 150 rpm was chosen as the optimum condition for the enterotoxin production. Brain heart infusion (BHI) broth was the medium of choice for production of SEA by strain FRI-722, with over 100 μg/ml being produced. Strain 1151m produced 20 μg/ml of SED in BHI medium which was 10 times that produced in shake flasks. The production of SEE was best in the Biosate + yeast extract medium, with adequate amounts being produced for purification.

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