Environmental Factors That Affect The Growth And Survival Of Microorganisms ( Potts 1994 )

The water activity also plays a big role in the microbes ability to survive as most cannot grow in a water activity level less than 0.91. Based on observations and construction of a data table, it was shown that the 1% NaCl solution had a water activity level of 0.99, the 7% NaCl solution 0.96 and the 15% NaCl solution 0.91. Based on the table it was expected that there would be no growth in the 15% NaCl solution as most microbes cannot survive at a water activity level of 0.91.

Bacteria are small, unicellular prokaryotic microbes. They have many morphologies, which include rod-shaped, spherical, spirals, helices, stars, cubes, and clubs. Classification of bacteria begins with either aerobic (requiring diatomic oxygen for growth) or anaerobic (not requiring O2 for growth). Bacteria can simply be narrowed down to gram positive (organism that stains purple or blue by Gram stain) or gram negative (organism that stains red or pink by Gram stain). Many physical and nutritional factors influence bacterial growth. Physical factors include temperature (psychrophiles, thermophiles, and mesophiles), pH (neutrophiles, acidophiles, and alkalinophiles), O2 concentration (aerobic

Abstract: Microorganism need to live in ideal conditions so they can grow. This experiment was performed to determine if there was a greater number of microorganisms in Winthrop lake than Winthrop wetlands. We determined this hypothesis because the lake was bigger. We also made the hypothesis that the pH level of the lake was going to be higher than the wetlands. We tested out the hypothesis by going out to Winthrop lake and wetlands and collecting samples of water. Back in the lab, we examined the samples under a microscope and recorded all the organisms we could find on Excel. Also, we tested the pH levels of the

Prokaryotes are ubiquitous, successfully adapting to diverse environments as well as developing symbiotic relationships with host organisms (Lengeler, Drews, & Schlegel, 1999). Prokaryotes may have both autotrophic and heterotrophic characteristics. A cyanobacteria is photosynthetic, commonly called blue-green algae, and may produce toxins (Crayton, 1993). Bacteria are most commonly associated in the general

Just like eukaryote species, not all bacteria species are identical in the way they behave, grow or interact with their environment (Mujtaba & DeJarnette, 2012). Microbes can be unique in the way they grow on nutrient agar (NA) plates. How their colonies form on the agar plates can also be an exclusive property of specific bacteria species. Microbes can grow in the presence of different nutrients, environments and can also be inhibited by or thrive in the presence of specific agents in the medium. For example inoculating a blood agar plate with the organism, can indicate its hemolysis activity, which it will fall in one of the three groups alpha (α), beta (β), or gamma (γ).

Many species of plants host microorganisms living inside the plant forming a mutually beneficial endosymbiosis. Bacteria or fungi that reside within plant tissue (roots, stems, and/or leaves) are referred to as endophytes. These endophyte communities may help to improve a plant’s fitness by promoting growth, protecting against disease, or facilitating nutrient acquisition. More specifically, endophytes within the plant community can help plants respond to stress that develops from biotic or abiotic influences like pests, heat, drought, saline, and soil conditions (Russell et al., 2003) Endophytes can help plants become better able to tolerate stress by allocating resources from one place to another (Rodriguez et al., 2009). Therefore,

This research paper is a primary research paper because the paper indicates that a study was done by several biologist and scientist on the microbial community in the Rhizosphere. Therefore, all the research, answers, and conclusion they all concluded based on their study was explained throughout this paper based on all the information they gathered. Also, the authors explain the process and methods they used to carry out and conduct this research on the microbial communities. I came down to this conclusion by understanding what they wrote is backed up by evidence by explaining the procedure they carried out to study these microbial communities.

Microorganisms have been used by human beings to their benefit for centuries. Ancient biotechnology utilized yeast to make bread and wine – perhaps well before they even knew that tiny microbes were causing bread to rise, or grapes to ferment! In the modern day, the use of microbes has extended so far as to actually help us reverse the damages we cause to the environment. One such environmental application of microorganisms is Bioremediation – the use of either indigenous or Hydrocarbonoclastic bacteria (HCBs) to rapidly digest hydrocarbons from oil spills.

The purpose of this lab was to observe the locations of bacteria growing in our school. I hypothesized that there would be more bacteria growing in areas with more exposure to students. My hypothesis was refuted. By the end of the growing period, the quadrant with the swab from the arm of the union bench had one colony, the quadrant with the swab from the girls’ locker room floor had 225 colonies, the quadrant with the swab from a soap dispenser had no colonies, and the quadrant with the swab from inside a toilet bowl had six colonies. This means that exposure to students was not the factor in determining the amount of bacterial growth, because the arm of the union bench has more exposure to students than the inside of a toilet bowl, and because

This experiment is about bacterial growth. We will demonstrate a bacterial growth curve using a closed system. Bacterial growth usually takes up to 12-24 hours to get an accurate result so we will be monitoring this growth between two classes. We also used different methods to determine bacterial growth as well as a few different calculations. One way of receiving data is by using a spectrophotometer where we will record the absorption at a given time to create the bacterial growth curve. We also used the plate count method after performing a serial dilution to calculate the actual cell density at different times given. By using this method we can count the population number of the same given and see the maximum cell density

Grow in very diverse conditions, which explain way they are found nearly everywhere on Earth. Although bacteria are good at adapting to their environments certain conditions promote bacterial growth, more than others . These conditions include temperature , moisture, and environmental oxygen. Understanding the conditions for bacterial growth can potentially help reduce the risk for bacterial growth can potentially help reduce the risk for bacterial infections and food poisoning. Most disease causing bacteria thrive in warm temperature, especially those close to body temperature. The human body , therefore , provides an ideal enviroment for many types of bacteria to grow. Bacteria need water (moisture) to grow and die without a water source,

Staphylococci are nonmotile, non-spore forming, spherical, catalase-positive, gram-positive bacteria. Staphylococci are classified as either coagulase-positive or coagulase-negative. Staphylococcus epidermidis lack the enzyme coagulase and are classified as a coagulase-negative staphylococcus (CoNS) (John et al.; Namvar et al.; Otto; Tortora et al. 591). Because of their thick peptidoglycan layer, gram-positive cocci are well suited for survival in harsh conditions, including living in areas with high concentrations of salt and osmotic pressure. Specifically, “S. epidermidis has eight sodium/ion exchangers and six transport systems for osmoprotectants” (Otto) which enable the bacteria to survive otherwise inhabitable conditions (Tortora et al. 591).

Over time, a cavity in the leaf developed that houses and protects the bacteria in a space without oxygen. The anabaena is then able to help the plant with nitrogen fixation. This cavity in the leaf also allows for cyanobacteria to be passed down through reproduction. (2)

The purpose of the two experiments was to determine the fundamental effects that temperature has on the growth and survival of bacteria. During the first experiment five different bacterial broth cultures of Escherichia coli, Pseudomonas fluorescens, Enterococcus faecalis, Bacillus subtilis and Bacillus stearothermophilus were individually incubated at temperatures of 5, 25, 37, 45 and 55°C for one week in an aim to distinguish the effect temperature has on growth and survival of the five different species. After one week they were observed for distinguishable changes by the turbidity showing an indication of bacterial growth, or the clarity an indication of no survival.

The effect of environmental factors such as temperature, osmotic pressure, oxygen concentration and pH on microbial growth and survival