What makes a bacterium gram positive or negative?
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It's the cell wall. The peptidoglycan in the gram positive bacterial cell wall retains the crystal violet and make them look purple in color.
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Salmonella are motile non-spore-forming, gram-negative gasterointestinal bacteria, which has to be ingested (usually secondary to contact with contaminated food, water or other materials (fomites) which have been contaminated) in order to cause infection and illness.
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This link is one of the better microbiology websites that I've used.\n\nhttp://www.textbookofbacteriology.net/
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Depends on what kind of bacteria. Some bacteria release CO2, some are phtosynthetic and release O2, some release NO-, NO2, NO3, or NH3. Most likely, the iron rusts.
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The Gram reaction is based on the structure of the bacterial cell wall.\nIn Gram-positive bacteria, the purple crystal violet stain is trapped by the layer of peptidoglycan which forms the outer layer of the cell.\nIn Gram-negative bacteria, the outer membrane prevents the stain from reaching the peptidoglycan layer in the periplasm. The outer membrane is then permeabilized by acetone treatment, and the pink safranin counterstain is trapped by the peptidoglycan layer.
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What are you trying to stain them with?\n\nYou haven't provided enough information to answer the question. \n\nMy best guess is that the microorganisms are gram negative and you're using a stain that only gram positive organisms can pick up.
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A definitive diagnosis requires demonstration or isolation of the organisms responsible for the infection. Direct Gram stain may be helpful because of the frequently unique morphology of Gram-negative anaerobic bacilli. In general, these organisms are pale staining and they may stain erratically. Fusobacterium cells may exhibit classic tapered ends and filamentous forms, with or without swollen areas and large round bodies. Direct gas-liquid chromatography of clinical specimens occasionally provides important clues to the presence of certain Gram-negative anaerobic bacilli. A large amount of butyric acid in the absence of isobutyric or isovaleric acid indicates the presence of Fusobacterium. The presence of succinic acid and only Gram-negative rods seen on Gram stain, or of both succinic and isobutyric acid in the specimen, indicates that Bacteroides is present. Both direct and indirect fluorescent antibody techniques may be useful for rapid detection of Bacteroides, Prevotella, and Fusobacterium in clinical material.
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each of these are salts.  A high salt level is a deterant to microbial growth, basically all the water inside the microbial cell wants to rush out into the salt to equilibrize concentrations.  Basically that kills the cell.   There are some bacteria however that are halophiles (salt-loving) that can live in high salt concentrations, most of those however exist in nature in very harsh environments such as sea basins which have dried and left a large amount of salt in the surrounding soil
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Here is a short answer for you.  :)\n\nGram negative bacteria have a lipopolysaccharide (LPS) molecule attached to their outer cell membrane.  LPS is an endotoxin that triggers an immune response in the form of fever and eventually shock as the toxin accumulates in the bloodstream.  \n\nGram positive bacteria do not have LPS.\n\nP.S.  There is no such species as Pseudomonas aureus  :)
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Selective media is used to select for the growth of a particular type of organism. They usually have a specific pH or component that inhibits the growth of certain organisms. MacConkey agar contains bile salts and crystal violet which inhibits the growth of Gram positive organisms. Eosin Methylene Blue agar (EMB) is also selective for Gram negatives. Phenylethlene agar (PEA) is selective for Gram positives and so is Mannitol Salt Agar (MSA). Hope that helps.
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the cell wall of the bacteria. Because in overall, bacteria can be classified as gram positive & gram negative. Those catagories are based on the difference on the reaction of their cell walls. \n\nBacteria are stained with gentian violet and then treated with Gram's solution; after being decolorized with alcohol and treated with safranine and washed in water, those that retain the gentian violet are gram-positive and those that do not retain it are gram-negative. \n\nThe different reactions are cause by the absorption-capability of the cell wall to the decolorization. Those bacteria which can absorpt the color factor (in the other word) the cell wall become decolorized as same as the color factor, are called gram positive. On contrary, for the gram negative.\n\nI hope this information help you to be more understand
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A\n\nAcid changes litmus to red. I am not sure what reacts with bases to produce salts. I am also not sure what becomes negative when exposed to other elements. You should review your chemistry properties.
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1. bacteria\n2. vectorborne\n3. b\n4. a\n5. yes\n6. muscle\n7. b\n8. 10\n9. c\n10. 10
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bacteria are prokaryotic(no nucleus)
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Bacteriocins are toxins that are produced by bacteria to kill  similar types of bacteria. Just as there is competition between different species of bacteria, there is also competition between different strains of the same species. They have similar mechanisms to most antibiotics. Many types of bacteria produce bacteriocins including Baccilli, Enteric bacteria (e.g. E.coli), and most gram-positives.
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Gram Positive bacteria have a different membrane structure than gram negative bacteria.  This results in a different uptake of a staining techinque where gram positive bacteria stain pink while gram negative stain purple.
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its a polymer which is present in the cellwall of bacteria.it is present in larger amounts in gram positive bacteria than in gram negative bacteria. it forms the basic principle for the gram staining procedure for bacteria. it contains amino acids like N-acetylmuramic acid and N-acetylglucosamine.in gram negative orgs it is in small amounts. they have more amounts of a substance called as lipopolysaccharide.