Characterization of two peptide-transport systems in Streptococcus faecalis

1980 ◽  
Vol 8 (6) ◽  
pp. 705-706 ◽  
Author(s):  
TIMOTHY M. NISBET ◽  
JOHN W. PAYNE
Keyword(s):  
Peptide Transport ◽  
Transport Systems ◽  
Streptococcus Faecalis

scholarly journals Functional Characterization of the Proteolytic System of Lactobacillus sanfranciscensis DSM 20451T during Growth in Sourdough

2005 ◽  
Vol 71 (10) ◽  
pp. 6260-6266 ◽  
Author(s):  
Nicoline Vermeulen ◽  
Melanie Pavlovic ◽  
Matthias A. Ehrmann ◽  
Michael G. Gänzle ◽  
Rudi F. Vogel
Keyword(s):  
Amino Acid ◽  
Proteolytic Activity ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Peptide Transport ◽  
Transport Systems ◽  
Peptide Hydrolysis ◽  
Degenerate Primers ◽  
Lactobacillus Sanfranciscensis ◽  
Peptide Uptake

ABSTRACT Protein hydrolysis and amino acid metabolism contribute to the beneficial effects of sourdough fermentation on bread quality. In this work, genes of Lactobacillus sanfranciscensis strain DSM 20451 involved in peptide uptake and hydrolysis were identified and their expression during growth in sourdough was determined. Screening of the L. sanfranciscensis genome with degenerate primers targeting prt and analysis of proteolytic activity in vitro provided no indication for proteolytic activity. Proteolysis in aseptic doughs and sourdoughs fermented with L. sanfranciscensis was inhibited upon the addition of an aspartic protease inhibitor. These results indicate that proteolysis was not linked to the presence of L. sanfranciscensis DSM 20451 and that this strain does not harbor a proteinase. Genes encoding the peptide transport systems Opp and DtpT and the intracellular peptidases PepT, PepR, PepC, PepN, and PepX were identified. Both peptide uptake systems and the genes pepN, pepX, pepC, and pepT were expressed by L. sanfranciscensis growing exponentially in sourdough, whereas pepX was not transcribed. The regulation of the expression of Opp, DtpT, and PepT during growth of L. sanfranciscensis in sourdough was investigated. Expression of Opp and DtpT was reduced approximately 17-fold when the peptide supply in dough was increased. The expression of PepT was dependent on the peptide supply to a lesser extent. Thus, the accumulation of amino nitrogen by L. sanfranciscensis in dough is attributable to peptide hydrolysis rather than proteolysis and amino acid metabolism by L. sanfranciscensis during growth in sourdough is limited by the peptide availability.

scholarly journals Isolation and characterization of mutants that produce the allantoin-degrading enzymes constitutively in Saccharomyces cerevisiae.

1982 ◽  
Vol 2 (9) ◽  
pp. 1088-1095 ◽  
Author(s):  
G Chisholm ◽  
T G Cooper
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Enzyme Synthesis ◽  
Common Element ◽  
Transport Systems ◽  
New Class ◽  
Degrading Enzymes ◽  
Isolation And Characterization ◽  
Nitrogen Repression ◽  
Internal Induction

Degradation of allantoin, allantoate, or urea by Saccharomyces cerevisiae requires the participation of four enzymes and four transport systems. Production of the four enzymes and one of the active transport systems is inducible; allophanate, the last intermediate of the pathway, functions as the inducer. The involvement of allophanate in the expression of five distinct genes suggested that they might be regulated by a common element. This suggestion is now supported by the isolation of a new class of mutants (dal80). Strains possessing lesions in the DAL80 locus produce the five inducible activities at high, constitutive levels. Comparable constitutive levels of activity were also observed in doubly mutant strains (durl dal80) which are unable to synthesize allophanate. This, with the observation that arginase activity remained at its uninduced, basal level in strains mutated at the DAL80 locus, eliminates internal induction as the basis for constitutive enzyme synthesis. Mutations in dal80 are recessive to wild-type alleles. The DAL80 locus has been located and is not linked to any of the structural genes of the allantoin pathway. Synthesis of the five enzymes produced constitutively in dal80-1-containing mutants remains normally sensitive to nitrogen repression even though the dal80-1 mutation is present. From these observations we conclude that production of the allantoin-degrading enzymes is regulated by the DAL80 gene product and that induction and repression of enzyme synthesis can be cleanly separated mutationally.

Regulation and characterization of two inducible amino-acid transport systems in Chlorella vulgaris

Planta ◽  
1983 ◽  
Vol 159 (5) ◽  
pp. 404-410 ◽  
Author(s):  
Norbert Sauer ◽  
Ewald Komor ◽  
Widmar Tanner
Keyword(s):  
Amino Acid ◽  
Chlorella Vulgaris ◽  
Amino Acid Transport ◽  
Transport Systems ◽  
Acid Transport

THE CHARACTERIZATION OF FECAL STREPTOCOCCI

1967 ◽  
Vol 30 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Richard C. Tilton ◽  
Warren Litsky
Keyword(s):  
Streptococcus Bovis ◽  
Streptococcus Faecalis ◽  
Positive Correlation ◽  
Fecal Streptococci ◽  
Streptococcus Faecium ◽  
Animal Feces

Summary Fecal streptococci were isolated from human and animal feces and frozen meat and poultry pies. Organisms from these sources could be classified in three major groups: Streptococcus faecalis, Streptococcus faecium, and Streptococcus bovis. Attempts to relate the presence of such organisms to their fecal source using the heat-tellurite test were unsuccessful. A positive correlation was noted between the ability of these organisms to reduce tetrazolium and tellurite and their fecal source.

scholarly journals Metabolite transport across the peroxisomal membrane

2006 ◽  
Vol 401 (2) ◽  
pp. 365-375 ◽  
Author(s):  
Wouter F. Visser ◽  
Carlo W. T. van Roermund ◽  
Lodewijk Ijlst ◽  
Hans R. Waterham ◽  
Ronald J. A. Wanders
Keyword(s):  
Fatty Acid ◽  
Metabolic Pathways ◽  
Adenine Nucleotides ◽  
Transport Systems ◽  
Peroxisomal Membrane ◽  
Metabolite Transport ◽  
Metabolic Functions ◽  
Current State ◽  
Made In

In recent years, much progress has been made with respect to the unravelling of the functions of peroxisomes in metabolism, and it is now well established that peroxisomes are indispensable organelles, especially in higher eukaryotes. Peroxisomes catalyse a number of essential metabolic functions including fatty acid β-oxidation, ether phospholipid biosynthesis, fatty acid α-oxidation and glyoxylate detoxification. The involvement of peroxisomes in these metabolic pathways necessitates the transport of metabolites in and out of peroxisomes. Recently, considerable progress has been made in the characterization of metabolite transport across the peroxisomal membrane. Peroxisomes posses several specialized transport systems to transport metabolites. This is exemplified by the identification of a specific transporter for adenine nucleotides and several half-ABC (ATP-binding cassette) transporters which may be present as hetero- and homo-dimers. The nature of the substrates handled by the different ABC transporters is less clear. In this review we will describe the current state of knowledge of the permeability properties of the peroxisomal membrane.

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