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Influence of Temperature on the Growth of Fecal Coliform

Md. Shaheduzzaman
Department of Microbiology, Stamford University Bangladesh, 51 Siddeswari Road, Dhaka 1217, Bangladesh

Md. Sayedur Rahman
Department of Microbiology, Stamford University Bangladesh, 51 Siddeswari Road, Dhaka 1217, Bangladesh

Ifra Tun Nur*
Department of Microbiology, Stamford University Bangladesh, 51 Siddeswari Road, Dhaka 1217, Bangladesh

Abstract/ Executive Summary:

The cellular response against environmental stresses is one of the most highly conserved regulatory features among all organisms. The exposure of cells to stresses such as heat shock leads to the accumulation of partially and fully denatured proteins that interfere with normal cellular function. Present study was designed to examine the growth and physiology of Escherichia coli at different temperatures in our laboratory condition. With a previous observation of Escherichia coli growth cessation by the increase in temperature on different culture media, current study further extended the examination of the influence of temperature on the growth behavior of fecal coliform on minimal media, a slight retardation in the colony and cell morphology was noticed for fecal coliform at 47°C within 36 hours to 72 hours of incubation. Consistent result was also found in spot test for fecal species at 45°C.

Keywords: Escherichia coli; Growth; Heat shock; Cell aggregates

Location: Department of Microbiology, Stamford University Bangladesh, 51 Siddeswari Road, Dhaka 1217, Bangladesh

Start Date:

End Date:

Program Area: Pest Management

Commodity: Bacteria, Temperature

Objectives:

The findings from the previous studies showing the various cellular activities of microbial cells to mitigate temperature and oxidative stress galvanized us to investigate the effect of high temperature on the viable cell number of E. coli.

Methodology:

Bacterial stain, medium and culture condition. Laboratory stock cultures of E.coli were used in this study. Minimal agar (MA) was used for the assay of cultureability. After 24 hour incubation on nutrient agar plates at 37°C, one loopful of bacterial culture was introduced into 5 ml nutrient broth followed by 0 rpm (rotation per minute) at 37°C for 4-6 hours (preculture). After adjusting optical density of the pre-culture at 600 nm (OD600) to 0.1, 30 µL each was introduced into 2 different sets of 30 ml of Minimal broth and incubated at, 45°C, 47°C at static condition (0 rpm). At every 12 hours cell growth was monitored by measuring OD600, and the formation of colony forming units (CFUs) were estimated by counting the colonies up to 72 hours at every 24 hour intervals. All the experiments were executed three times.

Microscopy. For the observation of cell morphology and arrangements, simple staining (Crystal Violet, Hucker’s Solution) was applied as previously done. An aliquot of 10 µl from each bacterial culture suspension were removed at 12 hours intervals and the shape and organization of cells were observed under light microscope (Optima Biological Microscope G206, manufactured in Taiwan) at 1000× magnification.

Spot test. As described previously, each of the bacterial culture suspensions were serially diluted in 9 ml nutrient broth to obtain up to 10-4 fold dilution. From each dilution, an aliquot of 5 µl was dropped on to the NA plates, dried off for 15 minutes, and finally, the plates were incubated at 37°C for 24 hours. Spotting was done at every 12 hours of growth.

Source of Information: Stamford Journal of Microbiology, 2016. Vol. 6, Issue 1, 20-23 ISSN: 2074-5346 (Print); 2408-8846 (Online)

Article Link (Online Journal):

Funding Source:

Budget:

Total Budget (Tk.) :

Achievement/Findings:

The capacity of Escherichia coli to mount a multifaceted response to the wide variety of stresses encountered by these organisms in vivo and in environmental reservoirs is only recently being fully appreciated. Variations in temperature range can occur rapidly, which requires an adaptive response for the bacteria to survive. They have shown a range of survival strategies and temperature related changes to the heat stress. Severe morphological change and other property variations like shrinking or elongating and at the later stages breaking down of the threadlike cellular structures were observed in prolonged heat stressed conditions. This is surely a significant finding in the strategies and phenomena and that occur in microorganism’s resistance mechanisms against heat stress. This study has been fueled through important information in the related field from previous researches which has worked with defining the effect and mechanism of different stresses including heat shock on certain kind of bacteria. This study has the potential to be studied further which can unveil new and important implications.

Knowledge Management: Journal