Showing papers on "Agar plate published in 1980"
TL;DR: During a nine-year period ending in 1977, scraped and cultured 663 corneal ulcers, and Pseudomonas was the predominant bacterial organism, and Fusarium was the most common fungus isolated.
464 citations
TL;DR: The reproducibility of the system was good, if attention was paid to the precision which the media were prepared and inoculated, and the effect of test variables, including incubation temperature, medium pH and inoculum size, was assessed.
Abstract: A system of 10 agar plate tests allowed presumptive identification of Candida albicans and differentiation of up to 512 strain types within the species. The yeast isolates were tested for acid and salt tolerance, proteinase production, resistance to 5-fluorocytosine and safranine, and assimilation of urea, sorbose, citrate and glycine. Media were inoculated semiquantitatively with a multiple-pronged device so that 55 yeasts and 5 reference strains could be printed on each plate at once. The results for the 9 strain differentiation tests were arranged in 3 groups to allow simple designation of types by 3-digit numbers. Mouth and vaginal samples from 85 patients and healthy volunteers yielded 45 different strain types, of which types 153, 157 and 357 were the most prevalent. The reproducibility of the system was good, if attention was paid to the precision with which the media were prepared and inoculated. The effect of test variables, including incubation temperature, medium pH and inoculum size, was asses...
181 citations
TL;DR: Infectivity of Bacteroides asaccharolyticus was dependent on the presence of a second organism and the growth factor was shown to be succinate which was able to replace the hemin requirement.
Abstract: Infectivity of Bacteroides asaccharolyticus (formerly B. melaninogenicus subsp. asaccharolyticus; see S. M. Finegold and E. M. Barnes, Int. J. Syst. Bacteriol. 27:388--391, 1977) was dependent on the presence of a second organism. An infective consortium consisting of B. asaccharolyticus and Klebsiella pneumoniae was defined. Neither organism was infective alone, but the Klebsiella could be replaced by organisms of a number of different genera. The nature of the infection appeared to be determined by the length of the lag period preceding the initiation of growth of B. asaccharolyticus. A rapid onset of growth led to the severe spreading form of the disease, whereas a slow initiation of growth resulted in the formation of a localized, self-limiting abscess. B. asaccharolyticus depends on the second or "helper" organism to produce a required growth factor which is not present at the inoculation site. The growth factor was shown to be succinate which was able to replace the hemin requirement. The dependency on succinate produced by K. pneumoniae was demonstrated in agar medium, in liquid culture, and in the infectivity assay. Any organism which produced succinate was able to stimulate growth of B. asaccharolyticus on agar medium and could replace K. pneumoniae as a member of the infectious consortium. The need for the second organism could be eliminated by inoculating B. asaccharolyticus together with agar-immobilized succinate or hemin.
158 citations
TL;DR: It was noticed that nutrient broth (NB) medium always gave less counts than its 100-fold dilution (DNB).
Abstract: Effect of dilution of plate counting media were studied on various terrestrial samples. It was noticed that nutrient broth (NB) medium always gave less counts than its 100-fold dilution (DNB). Many isolates on diluted media did not show appreciable growth on NB agar medium. Such isolates whose growth was suppressed in NB medium but not in DNB medium were called “DNB-organisms.” Percentages of DNB-organisms among isolates were 58% with Japan Alps soil, 30–40% with river and field samples, and 5–10% with avenue samples. About half the DNB-organisms were gram-negative, 10% were gram-positive, and the remainder were irregularly gram-stained organisms. About 65% of the DNB organisms from Japan Alps soil and 80% of those from the field soil showed irregularly rodshaped forms. Almost all irregularly gram-stained organisms were also irregularly rod-shaped. Those from river samples were either rod-shaped or filamentous. All the DNB-organisms were non-sporeformers.
75 citations
TL;DR: Tissue cultures from meristematic basal zone of the blade showed differentiation in the tissue from L. hyperborea as well as the formation of meiospores, which grew out into male and female plants.
Abstract: Starting material for the tissue cultures was the meristematic basal zone of the blade. Pieces treated 30–60 sec in hypochlorite solution were rinsed and placed on agar plates made from the artificial seawater ASP6 F2 solidified with 6 g agar l−1. After 6 weeks colorless callus-like tissue grew out from some pieces. Treatment with activated charcoal removed some inhibiting substances from the agar medium as numbers of callus developing pieces increased on such plates. A combination of 10−5 M NAA and 5 · 10−7 M kinetin gave a yellow-brown tissue. A differentiation in the tissue from L. hyperborea was observed as well as the formation of meiospores, which grew out into male and female plants. Thalli of sporophytes were observed but they never reached a length of more than one mm before they died or changed to an irregular pattern of growth.
44 citations
TL;DR: Results suggested that simple compounds present in legume root exudates may attract these bacteria and aid in their rhizosphere accumulation and, thus, in the nodulation process.
Abstract: Several Rhizobium spp were tested for chemotaxis using a soft agar assay. Bacteria migrated in chemotactic bands in response to substances present in the agar medium. R. japonicum S-110 formed chemotactic bands in response to l -arabinose, l -canavanine, and yeast extract but not to several other common compounds, including several amino acids and sugars. These results suggested that simple compounds present in legume root exudates may attract these bacteria and aid in their rhizosphere accumulation and, thus, in the nodulation process. A slow-migrating mutant of R. japonicum S-110 was isolated. Microscopic examination showed that mutant populations had a much lower proportion of motile cells than did wild-type populations. Greenhouse nodulation tests, in which mutant and wild-type cells were mixed and used as inoculum, indicated that the mutant had less nodulation potential.
44 citations
TL;DR: In this paper, a thin layer of cells can be separated from the agar medium by a disc of filter paper, and adhering cells are removed per step to measure growth of cell cultures.
Abstract: To measure growth of cell cultures with minimal or no disturbance, a thin layer of cells can be separated from the agar medium by a disc of filter paper. The disc and adhering cells are removed per...
42 citations
TL;DR: The results show that BHK-21 cell extracts support DBS 1050 growth in appropriate medium and an inhibition assay, based on a virus neutralization format, shows that a variety of common medium ingredients inhibit D BS 1050 growth.
Abstract: Growth on axenic agar medium is one of several characters by which mycoplasmas are defined. In apparent contradiction of the definition, DBS 1050 and other noncultivable strains ofMycoplasma hyorhinis do not grow on axenic medium but grow in cell culture. Our results show that BHK-21 cell extracts support DBS 1050 growth in appropriate medium. An inhibition assay, based on a virus neutralization format, shows that a variety of common medium ingredients inhibit DBS 1050 growth. The most potent activity was found in yeast extract. All other noncultivable strains ofM. hyorhinis tested have a yeast extract sensitivity, while cultivable strains do not. The apparent cell dependence of DBS 1050 can be attributed to growth inhibition due to factors present in a wide variety of peptones and extracts commonly used in medium; preferential growth in cell cultures is due to the absence of effective levels of these factors. Data are not available to determine if cell cultures provide growth factors not found in standard medium. The infraspecific taxon,M. hyorhinis cultivar α, is proposed for formerly noncultivable strains ofM. hyorhinis.
36 citations
TL;DR: Basidiospores from 14 strains of Hebeloma (Agaricales) representing 5 groups of mycorrhiza-forming species were tested for germination on a nutrient agar medium and a 10-fold increase or more in germination percentage was obtained in 4 out of 7 tested spore collections only by placing the growing root of a pine seedling among the spores on the agarmedium.
Abstract: Basidiospores from 14 strains ofHebeloma (Agaricales) representing 5 groups of mycorrhiza-forming species were tested for germination on a nutrient agar medium. Germination occurred in 13 strains but never exceeded 0.1%. A 10-fold increase or more in germination percentage was obtained in 4 out of 7 tested spore collections only by placing the growing root of a pine seedling among the spores on the agar medium.
33 citations
TL;DR: To isolate organisms capable of 16 alpha-dehydroxylating corticoids, Mueller-Hinton agar plates were seeded with fresh feces from Proteus-free rats and incubated anaerobically, yielding two obligate anerobes, strains 144 and 146, which elaborated the enzyme.
Abstract: For more than a decade it has been known that the fecal flora of humans and rats includes organisms capable of 16 alpha-dehydroxylating corticoids, but their identity has remained unknown. To isolate these organisms, Mueller-Hinton agar plates were seeded with fresh feces from Proteus-free rats and incubated anaerobically. On an average, 1 of every 35 colonies consisted of organisms synthesizing 16 alpha-dehydroxylase. Isolation of the individual colonies yielded two obligate anerobes, strains 144 and 146, which elaborated the enzyme. The steroid transformation could be attained by the microbial culture alone in prereduced media or in aerobic media in the presence of Escherichia coli. Although both strains were phenotypically similar to Eubacterium lentum, they differed between themselves in their enzymatic equipment.
29 citations
TL;DR: On addition of charcoal to agar medium the anther response in Datura innoxia Mill, increases dramatically and is better than in liquid medium, possibly due to adsorption of substances inhibitory to androgenesis and emanating from anthers.
Abstract: In recent years liquid medium has been shown to be better than agar-gelled medium for production of haploids by anther culture. However, on addition of charcoal to agar medium the anther response in Datura innoxia Mill, increases dramatically and is better than in liquid medium. For anthers with pollen at the premitotic stage, the best result was observed with 1% charcoal in Difco agar and 1.5% in Normal agar. The effect is possibly due to adsorption of substances inhibitory to androgenesis and emanating from anthers, as well as to substances present in the nutrient medium and agar.
TL;DR: The estuarine agar was found to be efficient for enumerating aerobic, heterotrophic bacterial populations of water, sediment, and oysters, and is recommended for plate counts ofEstuarine samples.
Abstract: A plate count agar was formulated for use in bacteriological analysis of estuarine samples and was tested together with standard plate count agar and an estuarine salts yeast extract agar for growth of aerobic, heterotrophic bacteria in water, sediment, and oysters. The estuarine agar was found to be efficient for enumerating aerobic, heterotrophic bacterial populations of water, sediment, and oysters, and is recommended for plate counts of estuarine samples.
TL;DR: Two rumen nitrate-reducing isolates of Desulfovibrio desulfuricans were found to hydrolyze cysteine with the production of sulfide and pyruvate, which resulted in blackening of colonies.
Abstract: Two rumen nitrate-reducing isolates of Desulfovibrio desulfuricans were found to hydrolyze cysteine with the production of sulfide and pyruvate When cultured on agar medium containing yeast extract with nitrate as the primary electron acceptor and ferrous chloride as the indicator, blackening of colonies occurred The blackening of colonies appeared sooner and was more intense when either cysteine or sulfate was added to the culture medium with nitrate present
TL;DR: It is concluded that CVNG medum is a useful adjunct to sputum bacteriology, especially in combination with digestion of theSputum samples by Cleland's reagent.
Abstract: The development and evaluation of a new selective medium for Streptococcus pneumoniae is described. It is shown that the new medium (crystal violet-nalidixic acid-gentamicin agar:CVNG) is highly selective for Strep. pneumoniae in sputum specimens containing other organisms and is also sensitive, being only marginally inhibitory when compared to Columbia blood agar. The advantages of the medium in routine use are presented, based on 206 consecutive sputum specimens. It is concluded that CVNG medum is a useful adjunct to sputum bacteriology, especially in combination with digestion of the sputum samples by Cleland's reagent.
Patent•
25 Feb 1980
TL;DR: In this paper, a container for growing anaerobic microorganisms having a cone-shaped dish and matching cone-shape cover that define between them a prescribed volume is described. But it is not shown in this paper.
Abstract: A container for growing anaerobic microorganisms having a cone-shaped dish and matching cone-shaped cover that define between them a prescribed volume. An overflow trough surrounds the dish, and the peripheries of the dish and cover seal together by excess agar medium carrying the organisms squeezed from the volume as the cover is applied to the dish. The colonies of organisms can be viewed either through the dish or cover because each is transparent.
TL;DR: A tube dilution test to evaluate the effectiveness of antibiotics against Bordetella pertussis is described and minimal inhibitory and minimal bactericidal concentrations for ampicillin by tube tests were found to be higher than values previously reported for agar plate tests.
Abstract: A tube dilution test to evaluate the effectiveness of antibiotics against Bordetella pertussis is described. Five B. pertussis strains, including a well-characterized research strain and four fresh clinical isolates, were tested with several antibiotics. Erythromycin showed the highest in-vitro activity of the antibiotics tested. A concentration of 0.12 microgram/ml was bacteriostatic for all strains, while 2 microgram/ml was bactericidal. Minimal inhibitory and minimal bactericidal concentrations for ampicillin by tube tests were found to be higher than values previously reported for agar plate tests.
TL;DR: This report deals with the isolation of fungi associated with poultry feeds in Nigeria by growing the fungi on MYEA plates at temperatures of 10, 15, 20, 45 and 50 C for 5 da and isolates were obtained.
Abstract: Spoilage of poultry feeds during storage due to mould infestation is particularly high in the tropics where the temperatures and high relative humidities provide excellent conditions for fungal growth. Fungal diseases of farm animals including poultry birds were reviewed recently (1) and the potential health hazards posed to animals and man were discussed by Lacey (5). In a previous study (7), thermophilic and thermotolerant fungi including zoopathogenic species were frequently obtained from poultry droppings. It was therefore necessary to determine whether these fungi were contaminants of the poultry droppings or were present in the feedstuffs originally taken in by the animals. This report deals with the isolation of fungi associated with poultry feeds in Nigeria. Random samples (approx 20 g each) of poultry feeds were collected from several farms and retail stores in the southwestern states of Nigeria. All the samples were analyzed within 5 da of collection. The pH values of 1: 1 (w/vol) suspensions and the moisture content of each of the samples were determined. The former was obtained with the aid of an electronic pH meter and the latter by recording the differences in weight between the fresh and the dried samples. For the isolations, 2 g of each sample were placed in several 11.5-cmdiam sterile Petri dishes (12 per sample) on 20 ml of malt-yeast-extract agar (MYEA), containing malt extract, 20 g; yeast extract, 2.5 g; NaNO3, 0.2 g; KCl, 0.05 g; sodium glycerophosphate, 0.05 g; K2SO4, 0.03 g; FeSO4 7H20, 0.01 g; agar, 15 g; distilled water, 1000 ml. Half of the Petri dishes (six per sample) were incubated at 25 C and the other half at 45 C to isolate mesophilic and thermophilic fungi respectively. All the Petri dishes were examined daily for fungal growth and colonies were transferred to fresh agar plates as soon as they appeared. Growth-temperature relations of the isolates were obtained by growing the fungi on MYEA plates at temperatures of 10, 15, 20, 45 and 50 C for 5 da. This method is particularly useful in determining growthtemperature requirements of fungi and has been extensively used (2, 6, 8) since trace growth can be detected by subjecting the Petri dishes to microscopic examination. For inoculum, agar-mycelial discs 200
TL;DR: Recovery succeeded better from frozen (−70°C) cell suspensions than from supernatant cell culture medium, and also better after direct inoculation on agar medium than after inoculation in broth, when testing cell cultures and live virus vaccines for contamination with mycoplasma are discussed.
TL;DR: In most instances, the more active inhibitory cultures produced more peroxide in refrigerated milk than less inhibitory ones, while a culture of Lactobacillus bulgaricus selected by the above procedure produced no inhibitory effect against the growth of psychrotrophic bacteria in non-agitated raw milk.
TL;DR: An agar medium containing 5% cholesterol has been developed for the isolation, enumeration, and characterization of cholesterol-reducing strains of Eubacterium.
Abstract: An agar medium containing 5% cholesterol has been developed for the isolation, enumeration, and characterization of cholesterol-reducing strains of Eubacterium.
TL;DR: The yeast flora of 16 samples of rumen contents of musk oxen (Ovibos moschatus) from East Greenland was examined in this paper, where variable numbers of yeast colonies developed on agar plates incubated at 25 °C, the counts being up to 136000 per g (Wt).
Abstract: The yeast flora of 16 samples of rumen contents of musk oxen (Ovibos moschatus) from East Greenland was examined. Variable numbers of yeast colonies developed on agar plates incubated at 25 °C, the counts being up to 136000 per g (wet wt). Of the 41 strains isolated, the majority belonged to Candida and Cryptococcus; others were species of Trichosporon, Rhodotorula, Torulopsis and Pichia. Very few colonies appeared on plates incubated at 37 °C, and only one species of Candida was isolated. Samples of rumen contents kept at about 5 °C for about 3 years contained a much greater number of yeasts, up to several million per g (wet wt) being counted on agar plates incubated at 25, 15 and 5 °C. The 30 strains isolated were of only three species of Candida, and none were obligate psychrophils.
Journal Article•
TL;DR: Uterine, cervical, and clitoral specimens on swabs from pony mares infected with contagious equine equine metritis (CEM) bacteria were streaked on agar plates, and colonies of CEM bacteria were easily recognized from large numbers of contaminants.
Abstract: Uterine, cervical, and clitoral specimens on swabs from pony mares infected with contagious equine equine metritis (CEM) bacteria were streaked on agar plates. Colonies of CEM bacteria were observed under CO2 incubation in 2 days on Eugon chocolate agar and Eugon blood agar plates. The diameter of the colonies varied from 0.2 mm to 1 mm in 2 days which increased to 0.3 mm to 2.0 mm on day 4. The colonies on Eugon chocolate agar plates on days 2 to 4 were shiny, brown, round, and convex, and easily glided when pushed with a loop. The diameter of the colonies on chocolate and blood agar plates made from tryptose blood agar base (TrCA or TrBA) was 0.2 to 0.3 mm on day 4. Due to their small size on TrCA or TrBA, colonies of CEM bacteria were easily recognized from large numbers of contaminants. The organism required hemin for its growth. It gelled in water, caused delayed hemolysis of blood agar plates, and was extremely susceptible to acid in the pH range to 3 to 4.5. A difference in growth of CEM bacterium was observed on primary isolation media obtained from two different commerical sources.
TL;DR: An investigation of nucleic acids and polyamines showed that subcultures initiated a rapid synthesis and accumulation of DNA; thereafter the levels of tRNA and rRNA increased, especially in the deceleration phase, the amount of t RNA always being higher than rRNA.
Abstract: Callus of the tumor hybrid of Nicotiana glauca × N. langsdorffii grew better on agar in flasks than on liquid medium in flasks or on agar medium in Petri dishes. Asymmetric callus without roots produced small leaves and parenchyma cells were the most common type of cell. Few meristematic clusters were present, but these were very active during exponential and deceleration growth phases. The volume of their nucleoli, which were large and stained intensely, was used as a marker of the cell cycle. Shortly after transplantation the tissue divided synchronously, but thereafter it became asynchronous. An investigation of nucleic acids and polyamines showed that subcultures initiated a rapid synthesis and accumulation of DNA; thereafter the levels of tRNA and rRNA increased, especially in the deceleration phase, the amount of tRNA always being higher than rRNA. The polyamines putrescine and spermidine are always in larger amounts than in the normal tissue, and spermine could be detected in trace amounts. Their m...
Journal Article•
31 Mar 1980
TL;DR: A single injection of 4.5 mg/kg of diacetoxyscirpenol (a toxin synthesized by Fusarium) into Mice challenged by C. albicans, increases significantly the development of an experimental candidiasis.
Abstract: A single injection of 4.5 mg/kg of diacetoxyscirpenol (a toxin synthesized by Fusarium) into Mice challenged by C. albicans, increases significantly the development of an experimental candidiasis. Suspensions of homogenized kidneys was spread on Sabouraud dextrose agar plates and the colonies of C. albicans were counted after 24 hrs incubation. The mean values were determined. Comparison of mean values calculated for kidneys from the Mice challenged with C. albicans and those challenged with C. albicans plus toxin gave highly significant results.
TL;DR: A modification of the plate loop count procedure for milk samples is described which incorporates use of a 0.5-ml diluent loop-rinse onto pre-dried agar medium in a 100-mm petri plate and Colony formation was more uniform than with the conventional method.
TL;DR: An antagonistic strain of Streptococcus faecium was isolated from human feces, and it displayed a marked inhibition of bifidobacteria on agar plates, and in liquid culture this isolate produced an antibacterial substance that can be partially purified by ammonium sulfate precipitation followed by gel filtration and ion-exchange chromatography.
Abstract: An antagonistic strain of Streptococcus faecium was isolated from human feces, and it displayed a marked inhibition of bifidobacteria on agar plates. In liquid culture this isolate produced an antibacterial substance that can be partially purified by ammonium sulfate precipitation followed by gel filtration and ion-exchange chromatography. Its activity was assayed by the inhibition of growth of Bifidobacterium longum. The substance was sensitive to digestion by proteolytic enzymes and alpha-amylase, but was resistant to treatment with 6 M urea, dithiothreitol, 2-mercaptoethanol, ethyl ether, chloroform, and lysozyme. It was also stable to heating at 100 degrees C for 60 min. Its molecular weight was estimated to be about 50,000 by gel filtration.
TL;DR: The pathogen was able to inhibit the growth of certain soil fungi on a nutrient-poor medium and a 'window' type of lysis of the pathogen, not previously described for any fungus, was observed only when it was paired with certain isolates on the nutrient- poor medium.
Abstract: One hundred and thirty-two isolates of fungi from the rhizosphere of wheat were tested for interaction with the take-all fungus (Gaeumannomyces graminis var. tritici) on a nutrient-rich and a nutrient-poor agar medium. Ten different types of interaction were observed. A 'window' type of lysis of the pathogen, not previously described for any fungus, was observed only when it was paired with certain isolates on the nutrient-poor medium. The pathogen was able to inhibit the growth of certain soil fungi on a nutrient-poor medium.
Journal Article•
TL;DR: The agar plate seems useful in culturing the differentiated chondrocyte either in mass culture or clonal culture, quite similar to those of the differentiated cartilage tissue.
Abstract: Freshly dissociated chondrocytes from chick embryonic sterna grew on the surface of solid substratum made of agar or agarose. The chondrocytes retained their differentiated traits such as morphology including intracellular organella and matrix forming ability. Extracellular matrix deposited around the cells exhibited strong metachromasia by staining with toluidine blue. Fibrous network was formed in the extracellular matrix. These characteristics are quite similar to those of the differentiated cartilage tissue. The agar plate seems useful in culturing the differentiated chondrocyte either in mass culture or clonal culture.
TL;DR: Comparisons for enumeration of microorganisms in fresh bologna, fresh ground beef, frozen turkey pot pie and bacterial suspensions of Pseudomonas fluorescens and Streptococcus faecalis found no significant differences between methods.