1.1.1 Glycoproteins and biosynthesis
1.1.1.1. N-Linked glycoproteins
N-Linked glycoproteins were traditionally considered unique for eukaryotic systems. It was not until more recently that their presences in bacteria and archaea become recognized. N-Glycans in eukaryotes share some common features and have a common core structure. They consist of common monosaccharide units. However, their structures in bacteria and archaea are more diverse and contain both common and rare monosaccharide building blocks.
1.1.1.1.1. N-Linked glycoproteins in eukaryotic systems
N-Glycans in eukaryotic cells have a common Man3GlcNAc2 core linked to the Asparagine (Asn) residue in the Asn-X-Ser/Thr sequons of proteins (where X is an amino acid other than proline) and can be classified to high-mannose, complex, and hybrid three types (Figure 1.1). They are presented on many secreted and membrane-bound glycoproteins.
Figure 1.1 Representative high-mannose, complex, and hybrid type N-glycans.
In Saccharomyces cerevisiae and vertebrates, they are initially synthesized on the cytoplasmic side of the endoplasmic reticulum (ER) membrane, starting with the transfer of N-acetylglucosamine phosphate (GlcNAc-P) from nucleotide-activated sugar donor UDP-GlcNAc to the ER membrane-anchored molecule dolichol phosphate (Dol-P). The dolichol pyrophosphate N-acetylglucosamine (Dol-P-P-GlcNAc) formed is further processed by glycosyltransferases. One GlcNAc and five mannose residues are subsequently added from UDP-GlcNAc and GDP-Man, respectively, generating Man5GlcNAc2-P-P-Dol. This sugar chain is flipped into the luminal side of ER membrane and extended by transfer of four mannose residues from Dol-P-Man and three glucose residues from Dol-P-Glc. The 14-sugar pr...
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...1–4Gal1–3diNAcBac–structure of Neisseria gonorrhoeae pilin is assembled by PglB, PglA and PglE onto Und-P, flipped by PglF to periplasm and transferred by PglO on to the Ser residue of pilin [21]. In an alternative pathway, PglH adds a Glc rather than two Gal residues to diNAcBac. In OST-independent O-glycosylation, glycosyltransferases add monosaccharides to proteins in the cytoplasm and the resulted glycosylated proteins are transported to the outer membrane or secreted by the flagellum [22].
1.1.1.2.3 O-Linked glycoproteins in archaea
The surface (S)-layer glycoproteins of archaea were found to be O-glycosylated. In Halobacterium salinarum, the cell envelope protein is modified with glucosylgalactose disaccharides and (uronic acid, glucose)-galatcotse trisaccharides at several sites [23]. Little is known about the O-glycosylation pathway in archaea at present.
Studies have shown pertactin, a 69kDa non fimbrial outer membrane protein, facilitates attachment of the bacteria to ciliated respiratory cells. Experiments conducted on humans to test the role of pertactin have shown no significant effect except with the results from Bassinet (4). Furthermore, filamentous haemagglutinin confers infection by attaching to the host cells in the lower respiratory tract. It is about 2nm wide, and 50n...
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.
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.
Coenzyme Q10 or CoQ10 is chemical compound. The human body makes its own Coenzyme Q10. However, as a person grows old, the levels decrease. Then again, the Coenzyme Q10 levels go down because of illnesses. Some prescribed drugs could deteriorate the levels too. A poor diet is another way to decline the amounts in the body. So, eating whole grains, liver and oily fish could help a lot.
Neisseria gonorrhoeae is a bacterium that is part of the Proteobacteria group in the Bacteria domain of the phylogenetic tree. The Proteobacteria group has five different groups, which are the Betaproteobacteria, Alphaproteobacteria, Epsilonproteobacteria, Deltaproteobacteria, and Gammaproteobacteria. Neisseria gonorrhoeae is part of the Betaproteobacteria group because it is a Gram-negative Bacteria and is most similar to other bacteria in that group. Betaproteobacteria are also known for their diversity in the fact that they consist of bacteria that are part of metabolic processes (Russell 2013, 577-578). Those bacteria are capable of doing so because they are chemoautotrophs, which oxidize inorganic molecules to get energy (Russell 2013, 573). Nitrosomonas is an example because it is a bacteria group that does nitrification (Russell 2013, 578). Neisseria gonorrhoeae also has the properties of chemoautotrophs even if it does not seem like it. In fact, Neisseria gonorrhoeae is a pathogen that lives in an environment composed of carbon dioxide. Therefore, Neisseria gonorrhoeae most likely metabolizes carbon dioxide as a form of energy so that it can grow (Lemire, Yen). Nevertheless, it is undeniable that Neisseria gonorrhoeae is part of the Betaproteobacteria group (Russell 2013, 578).
The Structure and Function of Carbohydrates Large biological molecules are called macromolecules, there are giant molecules (polymers) made up of repeating units (monomers). Carbohydrates are one of the main classes of biological molecules. Macromolecule units (monomers) are joined together by condensation reactions and hydrolysis reactions split macromolecules down into their individual units. Carbohydrates are molecules that contain elements of carbon, hydrogen, and oxygen. Carbohydrates have a 2:1 hydrogen to oxygen ratio, there are twice as many hydrogen atoms as oxygen atoms (the same proportion as in water).
1. Glycolysis is a multi-step process. The authors of Biological Science 5th edition stated ...
β- glucosidases or cellobiases (β- D glucoside glucohydrolases, EC 3.2.1.21)are very important components of the cellulase system in that they complete the hydrolysis to glucose of short-chain oligosaccharides and cellobiose which are released by the ot...
A Prokaryote is a single cell organisms that does not have a nucleus, which is divided into two major groups: archaeabacteria and bacteria. Prokaryotes are usually found in three common structures, such as bacillus is rod shaped, crocus is spherical-shaped, and spirillum is long shape. Although there are prokaryotes that are responsible for diseases there are also good types of bacteria that we need. Prokaryotes provide essential services to biological systems for instance food and agriculture.
The primary method to control gestational diabetes mellitus (GDM) is through dietary regulation. The most effective method to control GDM via diet is through carbohydrate restriction and/or selectivity. It is recommended that pregnant women with GDM reduce their carbohydrate intake to 40% of the total caloric intake or can maintain a 60% carbohydrate intake but those carbohydrates must all come from low glycemic index foods. Examples of low glycemic foods are apples, spinach, black beans, split peas, oatmeal, and quinoa. Additional suggestions are to eat complex carbohydrates instead of simple, refined sugars. Eat small, frequent meals and snack often in between meals in order to maintain constant glucose levels throughout the day.
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...
Fulda, K. G., and K. Lykens. "Abstract." National Center for Biotechnology Information. U.S. National Library of Medicine, 25 Aug. 0005. Web. 18 Mar. 2014. .
Cellular membranes are complex mixtures of proteins and lipids. Cell membranes are composed of a phospholipid bilayer, consists of two leaflets of phospholipid molecules and their fatty acid chain form the hydrophobic interior of the membrane bilayer; and proteins that span the bilayer and/or interact with the lipids on either side of the two leaflets. Transmembrane proteins are the type of membrane proteins which span the entire length of the cell membrane. They are embedded between the phospholipids and provides a channel through which molecules and ions can pass into the cell. They enable communication between cells by interacting with chemical messengers. Membrane proteins were classified into two comprehensive categories- integral and
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.
By taking a Carbon Dioxide, rich substance and mixing it with a yeast, solution fermentation will occur, and then it could be determined if it is a good energy-producer. In this study glacatose, sucrose, glycine, glucose, and water were used to indicate how fast fermentation occurred. The overall result shows that monosaccharides in particular galactose and glucose were the best energy source for a cell.