Pseudomonas belong to rRNA group I organism of gamma proteobacteria. They are gram negative aerobic rod-shape with polar flagella. They can be isolated from soil, decayed plant materials and rhizopheric region quite a numerous plant species. The strains of these bacteria called P. marginalis or P. fluorescens can be attributed to soft rot diseases in vegetables. The very complex groups of fluorescent, oxidase positive soft rot Pseudomonas are opportunistic macergens. The nomenclature of bacteria in the genus Pseudomonas has changed considerably during the last decennia. P. marginalis are pectinolytic P. fluorescens strains that cause soft rot on a wide range of hosts. The taxonomic and phytopathogenic status of P. marginalis is not well known however are biochemically and phenotypically indistinguishable from saprophytic strains of P. fluorescens biovars II, P. putida, and P. chlororaphis (now includes P. aureofaciens). Based on their ability to degrade pectin and macerate the plant parenhymateous tissues they are referred to as P. marginalis. Recently, based on 16S rRNA analysis Anzai et al. (2000) came up with 57 strains of Pseudomonas sensu stricto with seven subclusters: P. syringae group, P. chlororaphis group, P. fluorescens group, P. putida group, P. stutzeri group, P. aeruginosa group and P. pertucinogena group. Also, in the same genus Pseudomonas, some species have been found to be misclassified for instance P. aureofaciens and P. aurantiaca, which were reclassified into P. chlororaphis (Peix et al. 2007). Ever since the invention of genus Pseudomonas has undergone several taxonomic changes not only as far as the number of species included but also as far as the criteria used for their definition and delineation. In Berg...
... middle of paper ...
...ies (Guasp et al. 2000). The selection of the minimal principles necessary for species delineation and description are selected for each bacterial genus by a Committee created by experts in the given genus. The methods used in the taxonomy of the genus Pseudomonas and its related genera have been standardized by Subcommittee on the taxonomy. However, the minimal standards for genus Pseudomonas species description are yet to be cleared after the 2002 meeting of this Subcommittee, (De Vos and Yabuuchi 2002). Hence, the new species description of this genus must be based on the general minimal standards for bacterial species characterization (Stackebrandt et al. 2002). These general minimal standards needed for the classification of new species and/or subspecies must comprise 16S rRNA sequencing, DNA-DNA hybridization, fatty acid analysis and phenotypic classification.
The first day an unknown sample was assigned to each group of students. The first test applied was a gram stain to test for gram positive or gram-negative bacteria. The morphology of the two types of bacteria was viewed under the microscope and recorded. Then the sample was put on agar plates using the quadrant streak method for isolation. There were three agar plates; one was incubated at room temperature, the second at 30 degrees Celsius, and the third at 37 degrees Celsius. By placing each plate at a different temperature optimal growth temperature can be predicted for both species of bacteria.
The Gram positive bacteria has been nicknamed Posi. The Gram positive species’ morphology includes having an opaque opacity with a smooth margin. The moisture content of the Gram positive species is shiny and the pigmentation is gold. The Gram positive species grows at an optimal temperature of 37°C. The shape of the Gram positive species is a cocci, with an arrangement of grapelike clusters. The Gram positive species’ size ranges from .5-1.5 µm. Oxygen requirement of the Gram positive species is facultative, and has complete lysis of red blood cells. All results are summarized in Table
The purpose of this study is to identify an unknown bacterium from a mixed culture, by conducting different biochemical tests. Bacteria are an integral part of our ecosystem. They can be found anywhere and identifying them becomes crucial to understanding their characteristics and their effects on other living things, especially humans. Biochemical testing helps us identify the microorganism present with great accuracy. The tests used in this experiment are rudimentary but are fundamental starting points for tests used in medical labs and helps students attain a better understanding of how tests are conducted in a real lab setting. The first step in this process is to use gram-staining technique to narrow down the unknown bacteria into one of the two big domains; gram-negative and gram-positive. Once the gram type is identified, biochemical tests are conducted to narrow down the specific bacterial species. These biochemical tests are process of elimination that relies on the bacteria’s ability to breakdown certain kinds of food sources, their respiratory abilities and other biochemical conditions found in nature.
The purpose of this laboratory is to learn about cultural, morphological, and biochemical characteristics that are used in identifying bacterial isolates. Besides identifying the unknown culture, students also gain an understanding of the process of identification and the techniques and theory behind the process. Experiments such as gram stain, negative stain, endospore and other important tests in identifying unknown bacteria are performed. Various chemical tests were done and the results were carefully determined to identify the unknown bacteria. First session of lab started of by the selection of an unknown bacterium then inoculations of 2 tryptic soy gar (TSA) slants, 1 nutrient broth (TSB), 1 nutrient gelatin deep, 1 motility
The eighteenth exercise of the laboratory manual titled Unknown Identification and Bergey’s Manual is an experiment to identify an unknown bacterium. In this exercise, a student must randomly choose a numbered bacterium available to the class. The keys in Appendix H, located on the last pages of the book, are the major helpful tools in this exercise because it provides completed steps of tests that needs to be performed in order to distinguish certain bacteria. This means that in this exercise, various types of tests and techniques must be performed to identify the chosen unknown bacterium. The unknown bacterium that I selected was number thirty-nine in which I discovered as the Bacillus megaterium after conducting several tests.
(n.d.). Phenotypic methods of classifying microorganisms describe the diversity of bacterial species by naming and grouping organisms based on similarities. The differences between Bacteria, Archaea and Eukaryotes are basic.
Pseudomonas aeruginosa (P. aeruginosa) is a gram-negative, rod-shaped aerobic bacterium. It is a primary cause of hospital-acquired infections. P. aeruginosa is primarily a nosocomial pathogen. It also acts as an opportunistic pathogen, which can only infect a host that is immunocompromised, due to an underlying disease or medication. Although, P. aeruginosa can cause damage to virtually any tissue in the body, it almost never affects the tissues of healthy individuals. It is a problematic pathogen in hospitals; infecting individuals with cancer, burn wound, catheters and cystic fibrosis. P. aeruginosa is most recognized for its resistance to a wide range of antibiotics. In its planktonic form, P. aeruginosa has been found to have many virulence factors. However, P. aeruginosa within biofilms have been found to have a resistance to antibiotics 1,000 times greater than that of its planktonic counterparts [4]. Infections that are caused by bacterial biofilms are very persistent and very difficult to treat.
The purpose of this project was to identify unknown bacteria species from a mixed culture. The two unknown species were initially plated onto Tryptic Soy Agar (TSA), Eosin Methylene Blue (EMB), Mannitol Salt Agar (MSA), and blood agar plates to distinguish between the two different bacteria using colony size, color, shape, and growth characteristics. By identifying and inoculating the differing types of colonies, the two unknown bacteria were purified and able to be tested
Eastfield College Microbiology Laboratory Manual, 1st edition, Oliver, T. D. (Book Must Be Purchased New from Eastfield Bookstore and Cannot Be Sold Back to Bookstore at the End of the Semester), Kendall Hunt Publishing, 2013, Dubuque, IA. ISBN 9781465223784.
The O-specific polysaccharide is a heteropolysaccharide made up of a chain of repeating oligosaccharide units, ( 3 to 8 monosaccharides each) which are strain specific and determinative for the serological identity of the respective bacterium.O-polysaccharides are located on the outer surface exposed to the outer environment of the bacterium. 1-8 glycosyl residues can be seen in O- polysaccharide region as repeating units among various gram negative strains. These sugars varies in their types, sequence, substitution, chemical linkage, ring forms, substitution, presence or absence of non carbohydrate moiety etc giving a heterogenic nature for O-polysaccharides from different gram negative stains (Erridge et al., 2002).The diverse and specific arrangements utilizing various sugar monomers in the O-polysaccharide of LPS generates hundreds of distinct patterns or serotypes for each gram negative bacterial strains in nature. There are approximately 1-50 subunits (repeating units) well represented to complete the O-polysaccharide chain (Erridge et al., 2002). Each subunit encompasses three to eight sugar units and there may be up to fifty identical subunits in an O –chain. Some bacteria display shorter O-chains on average than others. The smooth type Salmonella species are in this category. In some cases, the last sugar unit at the non reducing end of O-chain carries a substituent which blocks the further addition subunits acting as a terminal signal. The sugar monomers in the repeating subunits of O-polysacchride chain may be linear or branched, homopolymers (with a single monosaccharide component) or heteropolymers in which frequently it was seen. A particular gram negative strain can produce multiple O-polysaccharide chain lengths...
There are numerous types of bacteria that can be found in every environment. Each bacterium has different morphology which includes shape, texture and pigment production. These bacteria also have different food requirements which are important in being able to identify a microorganism. Microorganisms are a diverse group containing all bacteria a single cell prokaryotic organism that is found in every type of environment, archea single cell microorganism that lacks nuclei and almost all microorganisms are protozoa a unicellular eukaryotic organism. By identifying the causative agent of a bacterium within an individual, an antibiotic can be developed to prevent health issues. Microorganisms are also used to make certain food products for human consumption. An example of this would be the production of yogurt. It has probiotics that help with digestive abnormalities amongst other things. Probiotics are microorganisms that are consumed to provide health benefits in the body. Probiotics work by replacing the disturbed microbe with ones that are useful to digest. With the methods that wer...
Talaro , K., & Chess, B. (2012). Foundations in microbiology. (8th ed., pp. 563-564). New York, NY:
...nvironmental Microbiology. New York: A John Wiley & Sons, Inc; 1992. pp. 125?156. Accessed December 2, 2013.
In the last decade, the number of prescriptions for antibiotics has increases. Even though, antibiotics are helpful, an excess amount of antibiotics can be dangerous. Quite often antibiotics are wrongly prescribed to cure viruses when they are meant to target bacteria. Antibiotics are a type of medicine that is prone to kill microorganisms, or bacteria. By examining the PBS documentary Hunting the Nightmare Bacteria and the article “U.S. government taps GlaxoSmithKline for New Antibiotics” by Ben Hirschler as well as a few other articles can help depict the problem that is of doctors prescribing antibiotics wrongly or excessively, which can led to becoming harmful to the body.
Bacterial cells, like plant cells, are surrounded by a cell wall. However, bacterial cell walls are made up of polysaccharide chains linked to amino acids, while plant cell walls are made up of cellulose, which contains no amino acids. Many bacteria secrete a slimy capsule around the outside of the cell wall. The capsule provides additional protection for the cell. Many of the bacteria that cause diseases in animals are surrounded by a capsule. The capsule prevents the white blood cells and antibodies from destroying the invading bacterium. Inside the capsule and the cell wall is the cell membrane. In aerobic bacteria, the reactions of cellular respiration take place on fingerlike infoldings of the cell membrane. Ribosomes are scattered throughout the cytoplasm, and the DNA is generally found in the center of the cell. Many bacilli and spirilla have flagella, which are used for locomotion in water. A few types of bacteria that lack flagella move by gliding on a surface. However, the mechanism of this gliding motion is unknown. Most bacteria are aerobic, they require free oxygen to carry on cellular respiration. Some bacteria, called facultatibe anaerobes can live in either the presence or absence of free oxygen. They obtain energy either by aerobic respiration when oxygen is present or by fermentation when oxygen is absent. Still other bacteria cannot live in the presence of oxygen. These are called obligate anaerobes. Such bacteria obtain energy only fermentation. Through fermentation, different groups of bacteria produce a wide variety of organic compounds. Besides ethyl alcohol and lactic acid, bacterial fermentation can produce acetic acid, acetone, butyl alcohol, glycol, butyric acid, propionic acid, and methane, the main component of natural gas. Most bacteria are heterotrophic bacteria are either saprophytes or parasites. Saprophytes feed on the remains of dead plants and animals, and ordinarily do not cause disease. They release digestive enzymes onto the organic matter. The enzymes breakdown the large food molecules into smaller molecules, which are absorbed by the bacterial cells. Parasites live on or in living organisms, and may cause disease. A few types of bacteria are Autotrophic, they can synthesize the organic nutrients they require from inorganic substances. Autotrophic bacteria are either photosynthetic or Chemosynthetic. The photosynthetic bacteria contain chlorophyll that are different from the plant chlorophyll. In bacterial photosynthesis, hydrogen is obtained by the splitting of compounds other than water.