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Micro-biochem mix

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medmaestro's version from 2016-01-11 19:51

Section

GRAM NEGATIVE BACTERIA
Question Answer
BrucellaBrucella agar
NeisseriaThayer-Martin agar
BordetellaBordet-Gengou agar
EnterobacteriaceaeVRBD agar
Haemophilus influenzae/Legionella pneumophilaBuffered charcoal yeast extract agar
Pseudomonas aeruginosaCetrimide agar
Salmonella-XLT agar,- DCA (Deoxycholate Citrate Agar) agar, -Salmonella/Shigella XLD agar
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(DCA agar - Deoxycholate Citrate Agar is a solid bacteriological growth medium.It is particularly useful for the isolation of organisms that cause bacilliary dysentery, salmonella strains that cause food poisoning and Salmonella Paratyphi. It is not so selective for Salmonella Typhi. This growth medium is inhibitory to most gut bacteria, in particular species of the genus Proteus, although these species do survive on DCA agar. It is therefore essential that suspected pathogens must be subcultured on a less inhibitory medium prior to identification. Salmonella spp appear to be yellow or colourless colonies, often with a dark centre. As there are many bacteria that also look like Salmonella on DCA, it is widely recommended that more selective agars are used for the identification of Salmonella, namely xylose lysine deoxycholate (XLD) agar. This growth medium is heat-sensitive and should be poured and cooled as soon as possible after addition of the deoxycholate, otherwise it tends to become very soft and difficult to handle. It has a pH of approximately 7.3, and when poured and cooled, appears light to dark pink in colour.XLT Agar (Xylose Lysine Tergitol-4) Is a selective culture medium for the isolation and identification of salmonellae from food and environmental samples. It is similar to XLD agar however the agar is supplemented with the surfactant, Tergitol 4, which causes inhibition of Proteus spp. and other non-Salmonellae. Successful growth of Salmonella will result in growth of red colonies with a black centre. Xylose lysine deoxycholate agar (XLD agar) is a selective growth medium used in the isolation of Salmonella andShigella species from clinical samples and from food. It has a pH of approximately 7.4, leaving it with a bright pink or red appearance due to the indicator phenol red. Sugar fermentation lowers the pH and the phenol red indicator registers this by changing to yellow. Most gut bacteria, including Salmonella, can ferment the sugar xylose to produce acid; Shigella colonies cannot do this and therefore remain red. After exhausting the xylose supply Salmonella colonies will decarboxylate lysine, increasing the pH once again to alkaline and mimicking the red Shigella colonies. Salmonellae metabolise thiosulfate to produce hydrogen sulfide, which leads to the formation of colonies with black centers and allows them to be differentiated from the similarly coloured Shigella colonies.Other Enterobacteria such as E. coli will ferment the lactose and sucrose present in the medium to an extent that will prevent pH reversion by decarboxylation and acidify the medium turning it yellow.
• Salmonella species: red colonies, some with black centers. The agar itself will turn red due to the presence of Salmonella type colonies.
• Shigella species: red colonies.
• Coliforms: yellow to orange colonies.
• Pseudomonas aeruginosa: pink, flat, rough colonies. This type of colony can be easily mistaken for Salmonella due to the color similarities.)

 

Question Answer
DIFFERENTIAL MEDIALactose fermenting gram negative ,MacConkey agar/Sorbitol-MacConkey agar ,Eosin methylene blue ,Hektoen enteric agar ,sulfur Bismuth sulfite agar
FUNGAL MEDIADermatophyte test medium Potato dextrose agar Sabouraud agar
NONSELECTIVE MEDIAChocolate agar ,Nutrient agar ,Plate count agar
OTHER/UNGROUPED MEDIACysteine lactose electrolyte deficient agar, Cystine tryptic agar ,Endo agar Lysine iron agar slant ,Müller-Hinton agar/PNP agar ,R2a agar, Simmons' citrate agar ,Trypticase soy agar ,Trypticase soy broth ,TSI slant
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General bacterial media

 

Question Answer
Bile esculin agar (BEA)BEA is used for the isolation of Enterococcus, as well as Group D Streptococcus species
CLED agarCysteine, lactose, electrolyte-deficient agar (CLED) agar is used to isolate and differentiate urinary tract bacteria, since it inhibits Proteus species swarming and can differentiate between lactose fermenters and nonfermenters.
Hektoen enteric agar (HEA)HE agar is designed to isolate and recover fecal bacteria belonging to the Enterobacteriaceae family. It is particularly useful in isolating Salmonella and Shigella.
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Lysogeny broth (LB)
Question Answer
MacConkey agar (MAC)MAC is a selective and differential medium used to differentiate between Gram-negative bacteria while inhibiting the growth of Gram-positive bacteria. The addition of bile salts and crystal violet to the agar inhibits the growth of most Gram-positive bacteria, making MacConkey agar selective. Lactose and neutral red are added to differentiate the lactose fermenters, which form pink colonies, from lactose nonfermenters that form clear colonies. An alternative medium, eosin methylene blue (EMB) serves a similar purpose.
Mannitol salt agar (MSA)MSA is also a selective and differential medium. The mannitol indicates organisms that ferment mannitol: mannitol fermentation produces lactic acid, lowering the pH and turning the plate yellow. The salt is to select for halophiles; organisms that cannot withstand a high salt content are unable to grow well.
Mueller-Hinton agar (MHA)MHA contains beef infusion, peptone, and starch, and is used primarily for antibiotic susceptibility testing. It can be in a form of blood agar.
Nutrient agarNutrient agar is usually used for growth of nonfastidious organisms and observation of pigment production. It is safe to use in school science laboratories because it does not selectively grow pathogenic bacteria.
Önöz agarÖnöz agar allows more rapid bacteriological diagnosis, as Salmonella and Shigella colonies can be clearly and reliably differentiated from other Enterobacteriaceae. The yields of Salmonella from stool samples obtained, when using this medium, are higher than those obtained with LEIFSON agar or Salmonella–Shigella agar (SSA).
Phenylethyl alcohol agar (PEA)PEA selects for Staphylococcus species while inhibiting Gram-negative bacilli (e.g., Escherichia coli, Shigella,Proteus, etc.).
R2A agar (R2A)A nonspecific agar, it imitates water, so is used for water analysis.
Tryptic (trypticase) soy agar (TSA)TSA is a general-purpose medium produced by enzymatic digestion of soybean meal and casein. TSA is frequently the base medium of other agar types; for example, blood agar plates are made by enriching TSA plates with blood.
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TSA plates support growth of many semifastidious bacteria, including some species of Brucella, Corynebacterium,Listeria, Neisseria, and Vibrio.
Question Answer
Xylose-lysine-deoxycholate agar (XLD)XLD is used for the culture of stool samples and contains two indicators. It is formulated to inhibit Gram-positive bacteria, while the growth of Gram-negative bacilli is encouraged. The colonies of lactose fermenters appear yellow.
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It is also used to culture possible Salmonella that may be present in a food sample. Most Salmonella colonies produce a black centre on XLD.
Question Answer
Cetrimide agarCetrimide agar is used for the selective isolation of the Gram-negative bacterium, Pseudomonas aeruginosa.
Tinsdale agar contains potassium telluritewhich can isolate Corynebacterium diphteriae.
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Fungal media

Question Answer
• Sabouraud agarSabouraud agar is used to culture fungi and has a low pH that inhibits the growth of most bacteria; it also contains the antibiotic gentamicin to specifically inhibit the growth of Gram-negative bacteria.
• Hay infusion agaris specific for the culturing of slime moulds (which are not fungi).
• Potato dextrose agar (PDA)is used to culture certain types of fungi.
• Malt extract agarhas a high content of peptone and is acidic. It is essentially used in the isolation of fungal microorganisms.
• Moss mediaKnop agar is used to culture axenically protonema and whole moss plants, e.g., those of Physcomitrella patens, a model organism.[7]
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• METABOLIC PATHWAYSITE OF OCCURRENCE
• GlycolysisCytosol
• Krebs/TCA/Citric acid cycleMitochondrial matrix
• GluconeogenesisPartly in cytosol and in mitochondria
• Glycogenolysis and GlycogenesisCytosol
• HMP shuntCytosol
• Protein synthesisCytosol
• Urea cyclePartly in cytosol and in mitochondria
• Triacylglycerol biosynthesisEndoplasmic reticulum(some are biosynthesized in mitochondria)
• Ether phospholipids, Plasmalogens and PAFs biosynthesisPeroxisomes
• Sphingolipid biosynthesisEndoplasmic reticulum
• Sphingomyelin biosynthesisGolgi apparatus > Plasma membrane
• Glycosphingolipid (Cerebrosides and Gangliosides) biosynthesisGolgi apparatus
• Cholesterol biosynthesisEndoplasmic reticulum > Cytosol
• Fatty acid biosynthesisCytosol
• Monounsaturated fatty acid biosynthesisEndoplasmic reticulum
• Ceramide biosynthesis from serineEndoplasmic reticulum
• Bile acid biosynthesisCytosol
• N-Linked Glycoside biosynthesisEndoplasmic reticulum
• O-Linked Glycoside biosynthesisGolgi apparatus
• Glycosaminoglyacans biosynthesisGolgi apparatus
• Elongation of fatty acid chainsEndoplasmic reticulum
• Fatty acid oxidationMitochondria
• Oxidation of very long chain Fatty acidsPeroxisomes (initially until it reaches the Octanyl stage)
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Question Answer
Triacylglycerol biosynthesisEndoplasmic reticulum(some are biosynthesized in mitochondria)
Sphingolipid biosynthesisEndoplasmic reticulum
Monounsaturated fatty acid biosynthesisEndoplasmic reticulum
Fatty acid biosynthesisCytosol
Cholesterol biosynthesisEndoplasmic reticulum > Cytosol
Ceramide biosynthesis from serineEndoplasmic reticulum
N-Linked Glycoside biosynthesisEndoplasmic reticulum
Elongation of fatty acid chainsEndoplasmic reticulum
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Question Answer
Sphingomyelin biosynthesisGolgi apparatus > Plasma membrane
Glycosphingolipid (Cerebrosides and Gangliosides) biosynthesisGolgi apparatus
O-Linked Glycoside biosynthesisGolgi apparatus
Glycosaminoglyacans biosynthesisGolgi apparatus
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Question Answer
Ether phospholipids, Plasmalogens and PAFs biosynthesisPeroxisomes
Oxidation of very long chain Fatty acidsPeroxisomes (initially until it reaches the Octanyl stage)
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