Bacterial Growth Curve

Several Escherichia coli (ATCC 11229) bacterial stopping points were launch victimization serial dilutions and simple agar-agar-agar casing pouring. The suppuration of the bacterial floricultures was evaluated exploitation spectrophotometric and small town enumeration rules. Data cool from a two-hour monitoring using 30-minute breakup sampling of bacterial hangings were plot against the 30-minute musical interval parade successions on a normal and semi recordraphic coordinates. The resulting gain curves showed that the cultures circulateed from the lag to the log chassis, which atomic form 18 typical of a bacterial ontogeny curve.The growth curves generated by spectrophotometric abstract were similar to the growth curve created by the village determine method. The techniques employed in this experiment may serve as basis in find out bacterial growth on both silver and solid culture media using separate types of bacterial species. The methods used in this p erformance may act as a method in estimating the issue of cells that are generated finished contrasting types of culture conditions.The colony enumerate method seems to be a more secure method because it involves certain visual recap of lodge colonies sequence the optical density yarns involve light(a) transmission through the turbidity of the bacterial culture wall hanging. The growth of bacteria pertains to a process wherein a single bacterial cell generates two identical female child cells. This simple doubling of bacteria is find in cultures that are classically conducted in microbiological laboratories. The quantification of bacterial growth is primarily performed through the use of either direct or indirect cell reckoning methods.Colony figuring is an example of a direct counting technique while the measurement of turbidity is an illustration of an indirect counting procedure. The progress of a bacterial curve is generally described through the use of a grow th curve (Novick, 1955). Four different phases comprise a bacterial growth curve. The lag phase involves the adaptation of inoculated bacteria to the conditions of the culture sensitive. This phase denotes that time that the bacteria are undergoing maturation. The logarithmic or exp superstarntial function phase involves the doubling of bacteria in culture.The rate of division is spy to logarithmically annex through time. The growth conditions and the chances of survival of the resulting daughter cells influence bacterial growth rate. The logarithmic growth of the bacterial culture is dependent on the availability of nutrients in the culture medium. The stationary phase pertains to the ebb in growth rate receivable to the exhaustion of nutrients in the culture medium and in turn, wastes have accumulated in the culture medium. During the death phase, the cultured bacteria lose nutrient resources and die. Materials and methods. The bacterial meanness of an E.coli culture (ATCC 1 1229) livestock culture was unflinching through the employment of serial dilutions and agar plate counts. Approximately 1 ml of the E. coli culture at log phase was transferred to a flask containing 100 ml of brain heart infusion broth. The suspension was slowly swirled and 5 ml was transferred to a cuvette for optimal density (OD) reading at 600 nm absorbance. Another 1 ml of the log phase bacterial culture was transferred to a test tube containing 9 ml of water. The suspension was mixed healthy thusly 1 ml of was then transferred to another test tube containing 9 ml of water.The serial dilution was performed six times, resulting in 7 dilutions. Approximately 1 ml of the 0 time point dilutions (10-4, 10-5, 10-6, 10-7) was plated with 15 ml of melted agar, swirled evenly and peg down aside to solidify. The optical density (OD) of the broth culture was taken every 30 transactions by transferring 5 ml of the broth culture to a cuvette for spectrophotometric reading. each(prenom inal) plated cultures were incubated for 24 hrs at 35-37oC. After 24 hrs incubation, the colonies that emerged on each plate were counted. The quiet data from the OD reading and colony counting were then analyzed and plot on semilog paper.Calculation for times time (g) of the bacterial culture was performed using the following compare g = time at absorbance 0. 41 time at absorbance 0. 21 Results. The growth of the bacterial culture based on the concentration of bacterial cells was unyielding using two methods. Optical density (OD) reading using the spectrophotometer showed that the number of bacterial cells in the culture increased for the 2 hours that the cultures were monitored. The optical density reading were then plotted against the 30-minute interval collection times (Figure 1).Based on the collected data, the calculated generation time is 32 transactions. The generation time was determined as follows g = 92 proceeding 60 minutes = 32 minutes Data collected from colony counting of broth cultures were plotted against the 30-minute interval collection times on a semilographic coordinates (Figure 2). The generation growth curve was determined to be 10. 1 minutes, indicating that the bacterial culture had cock-a-hoop 10 times from the start of the experiment. The run involving determination of bacterial concentrations over 2 hours of monitoring showed that the broth culture of E.coli showed an increase in its growth. The data showed the features of the lag and logarithmic phases of a growth curve wherein thither is a slow adaptation storey that shows minimal increase in the number of bacterial cells during the first 30 minutes of inoculation and then an exponential increase in the number of bacterial cells was observed soon after until the end of the observational period. The results generated from optical density readings and colony counting show the same increasing disregard in the number of bacterial cells in culture.The employment of two met hods in determining growth rates of bacterial cultures provided an fortune for comparison of these methods. The colony counting method seems to be a more reliable method because it involves positive visual inspection of live colonies on a Petri plate while the optical density readings but involve light transmission through the turbidity of the bacterial culture suspension and this method does not differentiate the live from the dead bacterial cells but in turn just counts the number of bacterial cells that are present in the cuvette.It should be noted that the number of viable bacterial cells serve as the source of bracing daughter cells hence it is better to bank on the results that are generated by actual colony counts derived from visual inspection of Petri plates.However, it in like manner should be noted that colony counting is also associated with a disadvantage wherein one colony may be still of at least two to several(prenominal) bacterial cells hence the exact number of cells seat not be determined. A colony composed of more cells can thus result in a bigger number of daughter cells than a colony comprised of only 2 bacterial cells. Reference Novick A (1955) Growth of bacteria. yearly Review of Microbiology 997-110.