Studies on the Proteolytic Bacteria of Milk I. A Medium for the Direct Isolation of Caseolytic Milk Bacteria

Frazier, W. C.; Rupp, Philip

doi:10.1128/jb.16.1.57-63.1928

Cited by 34 publications

(8 citation statements)

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“…The second medium contained (in grams per litre): meat extract 3.0; peptone 5.0; NaCl 5.0; skimmed milk 2.5; Ca (0H)2 0.15; CaCl2 0.05; agar 15; pH 7.0. (Frazier andRupp 1928, Brandt 1939). For the total number of heterotrophs the mean of the number of bacteria found on the two media was calculated.…”

Section: Aerobic Bacterial Countsmentioning

confidence: 99%

The Nitrogen Pathway in a Penguin Rookery

Lindeboom¹

1984

Ecology

182

121

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The most important nitrogen sources for the Marion Island ecosystem are the excreta of birds that forage at sea. Eighty percent of the nitrogen excreted by penguins during their molt fast appeared to be uric acid, with the remaining 20% mainly proteins and ammonia. The uric acid is rapidly degraded by aerobic and anaerobic microorganisms, and no uric acid could be detected in the penguin rookery deposit. Nitrification, followed by denitrification, occurs in the rookery deposit. However, laboratory experiments showed that both nitrification and denitrification are relatively unimportant processes in the rookery. Models of the nitrogen cycle in both a Macaroni Penguin and a King Penguin rookery during the molt fast and breeding season are given. In both rookeries the degradation of uric acid into ammonia and the subsequent evaporation are, quantitatively, the most important processes. The ammonia production in the rookeries of Macaroni Penguins as well as the heavy rains and the predominantly westerly winds have produced an "ammonia shadow" around the rookery where a vigorous plant growth occurs. The vegetation has formed a thick peat layer around the penguin rookery. 14C dating of this peat layer has shown that the Macaroni Penguins first bred on Marion Island °7000 yr ago.

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Section: Aerobic Bacterial Countsmentioning

confidence: 99%

The Nitrogen Pathway in a Penguin Rookery

Lindeboom¹

1984

Ecology

182

121

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“…The American Public Health Association (1967) rccommends the addition of loo/, (v/v) of sterile skimmilk to Standard Methods Agar, yct it has long been known that acid-forming bacteria can produce zones of clearing on such media. Two surveys (Frazier & Rupp, 1928;Lightbody, 1961) showed that 3745% of the zones of clearing on milk agar were not due to proteolysis. The most serious disadvantage, therefore, associated with the milk agar method is the need to flood the medium with a protein precipitant to codinn that zoncs of clearing are due to proteolysis and not caused by acid formed by the organisms as a result of sugar fermentation.…”

Section: An Improved Agar Medium For the Detection Of Proteolyticmentioning

confidence: 99%

“…The most serious disadvantage, therefore, associated with the milk agar method is the need to flood the medium with a protein precipitant to codinn that zoncs of clearing are due to proteolysis and not caused by acid formed by the organisms as a result of sugar fermentation. In an attempt to overcome some of these difficulties, Frazier & Rupp (1928) dcvised an opaque carbohydrate-free casein agar medium to eliminate clearing duc to acid production. The limitation of this medium for organisms not requiring carbohydrate has prevented its general adoption.…”

Section: An Improved Agar Medium For the Detection Of Proteolyticmentioning

confidence: 99%

An Improved Agar Medium for the Detection of Proteolytic Organisms in Total Bacterial Counts

Martley¹,

Jayashankar²,

Lawrence³

1970

Journal of Applied Bacteriology

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PLATE 1 . Tdluencc of Calf on the precipitation of para-caseins. On each plate of SMCA, Micrococcus jreuclerweicl~ii is a t tho top with Serratia marcescens lower left, and Pseuclomonas fragi lower right. The medium contained: ( a ) no additional Caa+; (b) 0.015 m; 0.02 N. Incubation, 48 h/30'. YLATW 2. Zones duo t o protoolysis formed on ( a ) SMCA by Staphylococcus aureus (above), Sarcirto Zuten (lowcr left) andP6eudomonas fragi (lower right), and the effect of thew organisms on milk agar (0) before and (c) aftrr flooding with acidified HgCI, solution. Incubation, 60 h a t 30". Bact. f. 1). 3G4. YCATE 8. Prot,eolytic (P) and nonprotrolyt ir (N P ) roloriios clcarly diffrrontiatrrl o n a SMCA plats used to dotormine thc total and proteolytic count of raw milk. Incubation, 48 h a t 30".

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“…Bacteria were screened for the synthesis of extracellular proteases and lipases at temperatures of 4, 10, and 18 • C. Synthesis of proteases was assessed based on the original method by Frazier and Rupp (1928) by placing a volume of 10 µl of a pre-grown culture onto a calcium caseinate agar plate (Sigma-Aldrich, St. Louis, United States) and monitoring the formation of a clear halo around the colony during incubation for up to 4 weeks. As for lipases, bacterial strains were first screened for a general lipolytic activity by placing a volume of 10 µl of a pre-grown culture onto a R2A agar plate supplemented with sunflower oil (1% v/w) and rhodamine B (0.001% v/w) and monitoring under UV irradiation the formation of a fluorescent orange-pink halo around the colony (Beisson et al, 2000).…”

Section: On Plate Screening For Cold-active Enzymesmentioning

confidence: 99%

Discovery and Characterization of a New Cold-Active Protease From an Extremophilic Bacterium via Comparative Genome Analysis and in vitro Expression

et al. 2020

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Following a screening of Antarctic glacier forefield-bacteria for novel cold-active enzymes, a psychrophilic strain Psychrobacter sp. 94-6PB was selected for further characterization of enzymatic activities. The strain produced lipases and proteases in the temperature range of 4-18 • C. The coding sequence of an extracellular serine-protease was then identified via comparative analysis across Psychrobacter sp. genomes, PCRamplified in our strain 94-6PB and expressed in the heterologous host E. coli. The purified enzyme (80 kDa) resulted to be a cold-active alkaline protease, performing best at temperatures of 20-30 • C and pH 7-9. It was stable in presence of common inhibitors [β-mercaptoethanol (β-ME), dithiothreitol (DTT), urea, phenylmethylsulfonyl fluoride (PMSF) and ethylenediaminetetraacetic acid (EDTA)] and compatible with detergents and surfactants (Tween 20, Tween 80, hydrogen peroxide and Triton X-100). Because of these properties, the P94-6PB protease may be suitable for use in a new generation of laundry products for cold washing. Furthermore, we assessed the microdiversity of this enzyme in Psychrobacter organisms from different cold habitats and found several gene clusters that correlated with specific ecological niches. We then discussed the role of habitat specialization in shaping the biodiversity of proteins and enzymes and anticipate far-reaching implications for the search of novel variants of biotechnological products.

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Studies on the Proteolytic Bacteria of Milk I. A Medium for the Direct Isolation of Caseolytic Milk Bacteria

Cited by 34 publications

References 0 publications

The Nitrogen Pathway in a Penguin Rookery

The Nitrogen Pathway in a Penguin Rookery

An Improved Agar Medium for the Detection of Proteolytic Organisms in Total Bacterial Counts

Discovery and Characterization of a New Cold-Active Protease From an Extremophilic Bacterium via Comparative Genome Analysis and in vitro Expression

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