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...
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...he viability of the microorganism nor the biological potency of the LPS. Deoxysugars are frequent components in O-chain structures but sugars that are more characteristic of the inner core region like heptose are seldom present. The most common substituents are O- and N- acetyl phosphate and phosphorylethanolamine groups. Amino acids in amide linkages, acetamidino groups as well as formyl groups and glyceric acid are often found as non stoichiometric substituents(Brade et al., 1999). The extended O-polysaccharide chains out from the bacterial outer membrane acts as a shield which enable the bacteria to get away from the lytic activity provided by the complement cascade. Many gram negative strains require O-polysaccharide as an essential component for the survival in host system as it prevents the attack from complement membrane attack complex (Joiner et al., 1984).
The isolate possesses some enzymes required for hydrolytic reactions. Hydrolytic enzymes found to be secreted from the bacterium, are -amylase, casein, and PYRase. In the starch hydrolysis and casein tests, there was a zone of clearing around the bacterium, which was indicative of the secreted enzymes necessary to break down starch and casein. In the PYR test, the presence of PYRase was detected by a color change to red on the PYR disc after the addition of the PYR reagent (p-dimethylaminocinnamaldehyde). Hydrolytic enzymes for which the EI tested negative were urease, gelatinase, and DNAse. In the Urea Hydrolysis test, it was observed that the urea broth did not have a color change, indicating that there was no urease secreted to break down urea in the broth. Similarly, there was no gelatinase present to break down gelatin in the Gelatin Hydrolysis test, so the nutrient gelatin remained solid. It was concluded that the EI does not possess DNase because there was no clearing zone around the bacteria, indicating that DNA had not been
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 results of the gram stain test were cocci and purple. This indicated that the unknown bacteria were gram positive. The gram stain test eliminated Escherichia coli, Klebsiella pneumonia, Salmonella enterica, and Yersinia enterocolitica as choices because these bacteria are gram negative. Next a Blood Agar plate was used because in order to do a MSA or a Catalase test there needs to be a colony of the bacteria. The result of the Blood Agar plate was nonhemolytic.
Because B. pertussis is a gram-negative bacteria, it possesses the endotoxin lipopolysaccharide (LPS). However, its LPS is different from that of the other gram-negative bacteria, in that it is heterogeneous with an alternative form of the Lipid A, called Lipid X. Although not fully understood at the time, it seems that Lipid X has a greater capacity for virulence.
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. Bacteria can function and reproduce as single cells but often combine into multicellular colonies. Bacteria are also surrounded by a cell wall. Archaea differ from bacteria in their genetics and biochemistry. Their cell membranes are made with different material than bacteria. Just like bacteria, archaea are also single cell and are surrounded by a cell wall. Eukaryotes, unlike bacteria and archaea, contain a nucleus. And like bacteria and archaea, eukaryotes have a cell wall. The Gram stain is a system used to characterize bacteria based on the structural characteristics of their cell walls. A Gram-positive cell will stain purple if cell walls are thick and a Gram-negative cell wall appears pink. Most bacteria can be classified as belonging to one of four groups (Gram-positive cocci, Gram-positive bacilli, Gram-negative cocci, and Gram-negative bacilli) (Phenotypic analysis. (n.d.).
It has an outer membrane that contains lipopolysaccharides, a periplasmic space with a peptidoglycan layer, and an inner cytoplasmic membrane. It also consists of adhesive fibres. Some strains of E. coli are piliated and are capable of accepting, as well as transferring plasmids to and from other bacteria. This enables the bacteria under stressful or bad conditions to survive. Although its structure is simple with only one chromosomal DNA and a plasmid, it can perform complicated metabolism to help maintain its cell division and cell growth.
Streptococci can be separated into groups by a polysaccharide antigen that is deep inside the cell wall. The groups are labeled by the letters ranging from A to R, each group represents a different type of organism that it mostly infects. Group A is mainly pathogenic to humans, while group B is found in cattle. Groups C to R infect animals of lesser complexity. Streptococcus pyogenes is part of group A, which means that the polysaccharide antigen is composed of rhamnose and N-acetylglucosamine and its main host is in humans.
Pasteurella multocida is a zoonotic bacterium that infects a range of hosts such as livestock, poultry, domestic pets, and even humans. (1,2) The bacterium is a small, nonmotile, bipolar staining, gram-negative coccobacillus. (2) Classifications of these microorganisms are based on the bacteria capsule type and lipopolysaccharide antigens. Pasteurella multocida have five distinct carbohydrate polymer capsular types which are A, B, D, E, and F. (3) The lipopolysaccharide antigens classifies Pasteurella multocida into 16 Heddleston serovars that produce different lipopolysaccharide structures that help protects the bacteria from host immune response. (3)
Many say that history repeats itself, and throughout history, the spread of food-borne diseases has been constantly threatening humans. Salmonella, a disease which attacks numerous people a year, has returned, infected, and put people under panic of what they are eating. According to Foodborne Diseases, it is stated that “Salmonella comprises a large and diverse group of Gram-negative rods. Salmonellae are ubiquitous and have been recovered from some insects and nearly all vertebrate species, especially humans, livestock, and companion animals” (Gray and Fedorka-Cray 55). Because of the flexibility and the ability to reproduce rapidly, this infamous disease still remains as one of the most common threats in our society as well as an unconquerable problem that humans face these days.
Mycobacterium is a bacillus –a rod shaped, cord forming, bacteria. The reason the organism creates problems for its host is due to the fact that its cell wall contains large wax like lipids called mycolic acids. Mycolic acids are strong hydrophobic molecules that form a lipid...
The slight differences in the way their atoms are arranged give them slightly different properties. These are shown below: α-glucose: β-glucose: Galatose: Fructose: [IMAGE] [IMAGE] The main function of monosaccharide is that they are able to move through bodies, gut walls and therefore important as a source of energy. All other carbohydrates have to be converted to monosaccharides before energy can be released and its is due to it’s small size they are very soluble and it is the form of monosaccharides that all carbohydrates are carried in the blood.
M proteins: M proteins are found on the surface of the organism and protect it against phagocytosis. The M proteins prevent the attachment of complement proteins to the cell. Complement proteins which are attached to the bacterium “tag” it for destruction by phagocytic cells, such as neutrophils and macrophages, in a process called opsonisation. By inhibiting this process, the M protein allows the group A streptococcus to survive longer...
Alkaline phosphatase, or AP, is an enzyme that is responsible for dephosphorylation, or removing phosphate groups, of various types of molecules such as proteins and nucleotides. It has a molecular weight of 140-160 kilo-Daltons and as said in the name, alkaline phosphatase works in an environment with pH values ranging from 7.5-9.5, which is an alkaline, or basic, environment. And according to Sigma-Aldrich, alkaline phosphatase can be used to “to dephosphorylate the 5'-termini of DNA or RNA to prevent self-ligation” (sigmaaldrich.com). Alkaline phosphatase in gram-negative bacteria can be found in the periplasmic space, which is found outside of the cell membrane. Because of this, it is subject to various types of environmental activity, making alkaline phosphatase more resistant to being denatured, inactivated, and degraded, while also giving AP a higher rate of activity.
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.