( en Inventor 赵凯 张小燕 郝妍 常志威 孙立庆 夏昕 Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.) Granted Application number CN2011103188771A Other languages Chinese ( zh) Google Patents CN102344898A - Klebsiella variicola strain /jreynolds/microbiology/2421/lab_manual/casein.CN102344898A - Klebsiella variicola strain.McGraw-Hill Companies, New York, NY, USA.
#Gelatin hydrolysis test for bacillus subtilis manual#
Benson’s Microbiological Applications: Laboratory Manual in General Microbiology, 11th ed. Experiments in Microbiology, Plant Pathology and Biotechnology, fourth revised edition, New Age International (P) limited, Ansari road, Daryaganj, New Delhi-110002. Pearson Benjamin Cummings, San Francisco, CA, USA. Microbiology: A Laboratory Manual, 8th ed. It is recommended that biochemical, immunological, molecular, or mass spectrometry testing be performed on colonies from pure culture for complete identification.Identification of organisms that can hydrolyse casein, such as Streptomyces, Pseudomonas , and Actinomadura.For the differentiation of aerobic actinomycetes based on casein proteolysis.Differentiating among Enterobacteriaceae, Bacillaceae, and several other families.Helpful in identifying bacteria that grow in milk.Negative Test: No clearing is observed around and/or beneath the inoculum.Positive Test: Clearing is observed around and/or beneath colony growth (hydrolysis).Examine the milk agar plate cultures for the presence or absence of a clear area, or zone of proteolysis, surrounding the growth of each of the bacterial test organisms.Inoculate the organism on the plate either a straight line or a zig-zag.SM powder 28.0gm/L, Tryptone 5.0gm/L, Yeast extract 2.50gm/L, Dextrose (Glucose) 1.0gm/L, Agar 15.0gm/L, Final pH ( at 25☌) Method In the absence of protease activity, the medium surrounding the growth of the organism remains opaque, which is a negative reaction. This loss of opacity is the result of a hydrolytic reaction yielding soluble, non-colloidal amino acids, and it represents a positive reaction. Similar to other proteins, milk protein is a colloidal suspension that gives the medium its color and opacity because it deflects light rays rather than transmitting them.įollowing inoculation and incubation of the agar plate cultures, organisms secreting proteases will exhibit a zone of proteolysis, which is demonstrated by a clear area surrounding the bacterial growth. The medium is composed of nutrient agar supplemented with milk that contains the protein substrate casein. For demonstration of such an activity, in the lab, milk agar is used. Some microorganisms have the ability to degrade the casein protein by producing proteolytic exoenzyme, called proteinase (caseinase). To differentiate the organism on the basis of production of exoenzyme proteinase (caseinase).To determine the ability of the organism to degrade the casein protein.The reaction then liberates the amino acids which are low-molecular in weight which can be transported through the cell membrane for use in the synthesis of structural and functional cellular proteins. The function of these proteases is to cleave the peptide bond CO–NH by introducing water into the molecule. These are mediated by extracellular enzymes called proteases. Before their assimilation into the cell, proteins must undergo step-by-step degradation into peptones, polypeptides, dipeptides, and ultimately into their building blocks, amino acids. It makes around 85% of the protein found in milk as well as the white color of milk.Ĭasein is way too large to enter the cell membrane. Casein, the major milk protein, is a macromolecule composed of amino acid subunits linked together by peptide bonds (CO-NH).
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