Estimation of Microbial Viability

Thomas, Vincent; Doughty, N. A.; Fletcher, R.H.; Robertson, John

doi:10.2307/2528631

Cited by 3 publications

(2 citation statements)

References 6 publications

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“…The viability of individual organisms was estimated from the cluster viability and the cluster size distribution by using formulae derived on the basis that dead organisms were randomly distributed through clusters of all sizes (Thomas, Doughty, Fletcher & Robertson, 1972). The cluster-size distribution, defined as the proportion of organisms in clusters of different sizes, was determined by examining slide cultures before growth of the organisms had occurred.…”

Section: Methodsmentioning

confidence: 99%

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Survival of Nocardia corallina and Degradation of Constituents during Starvation

Robertson

Batt

1973

Journal of General Microbiology

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The survival of Nocardia corallina and the degradation of constituents were examined during periods of starvation. Organisms were harvested at the end of the growth phase and were starved, after resuspending in phosphate buffer containing Mg2+, with vigorous aeration at 30 "C. Viability fell gradually to 50 % over a period of 480 h. After 48 h of starvation the dry weight of the organisms was reduced by 35 % and the Qo, was decreased from I o to approximately I. The fall in dry weight coincided with a decrease of microbial polysaccharide from 25 % to 7 % of the initial dry weight. After this degradation of polysaccharide there was a decrease in microbial protein and a release of ammonia into the supernatant. The contribution of different constituents to the total decrease in dry weight during a period of 240 h starvation was; polysaccharide, 40 %; protein, 25 %; RNA, 6 %; total fatty acids, 5 %. Loss of viability could not be directly correlated with the utilization of any particular constituent.

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Section: Methodsmentioning

confidence: 99%

“…Organisms suspended in phosphate buffer were incubated at 30 "C with shaking for 131 h. The means and standard errors of results of single analyses on each of six flasks are presented. Viability of individual organisms was estimated from the cluster viability by using formulae(Thomas et al 1972). Dry wt (M); viable organisms (a); total organisms (0).Fig.…”

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confidence: 99%

Survival of Nocardia corallina and Degradation of Constituents during Starvation

Robertson

Batt

1973

Journal of General Microbiology

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The Plate Count in Aquatic Microbiology

Buck

1979

Native Aquatic Bacteria: Enumeration, Activity, and Ecology

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The application and inherent difficulties of the traditional plate count the technique and its variations are presented. While the plate count has been, and continues to be, used for enumeration of microorganisms in natural waters, recent criticisms of the technique appear increasingly in the literature. Accordingly, the quantitative nature of the plate count in discussed in relation to limitations of the procedure and current alternatives for microbial enumeration. Constant evaluation of newly evolving quantitative procedures for the denomination of microbial numbers, biomass, and activity is recommended to prevent the “standardization” of techniques which, like the plate count, subsequently become subject to debate as to their appropriateness in ecological studies. The plate count is still seen as a valuable tool for its originally intended purpose and should be supplemented and reevaluated in conjunction with contemporary quantitative methods.

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Methods for Detecting Recombinant Dna in the Environment

Jain

Burlage

Sayler

1988

Critical Reviews in Biotechnology

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The successful introduction of genetically modified and genetically engineered microorganisms into the environment requires a quantitative evaluation of the survival and dispersion of the microorganisms and specific gene(s) in the environment. The objective of this article is to examine the applicability, suitability, and significance of existing and new methods for detecting and monitoring the recombinant genes or organisms introduced into the environment. Conventional microbiological method(s) involving the selective and differential growth of microorganism(s) adn other quantitative approaches such as the most-probable-number (MPN) method and direct microscopic observation (e.g., acridine orange direct count analysis) have drawbacks and are not specific or universally applicable. Direct enumeration by immunofluorescence by the use of fluorescent dye seems more sensitive although still not perfect. However, the molecular methodologies such as the use of gene probes, plasmid epidemiology, antibiotic resistant marker strains, and protein electrophoresis and bacteriophage sensitivity are receiving more attention. As yet, the technology of DNA:DNA hybridization appears to be very useful, sensitive, and accurate for detecting and monitoring the microorganisms in the environment, although improvements are required. New approaches can be developed which may include biochemical signature compounds as well as gene cassettes to be used in a complementary fashion with conventional and molecular techniques for quantifying specific genotypes and genes in the environment.

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Estimation of Microbial Viability

Cited by 3 publications

References 6 publications

Survival of Nocardia corallina and Degradation of Constituents during Starvation

Survival of Nocardia corallina and Degradation of Constituents during Starvation

The Plate Count in Aquatic Microbiology

Methods for Detecting Recombinant Dna in the Environment

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