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Rapid Quantitative Detection of Listeria monocytogenes in Meat Products by Real-Time PCR. David Rodríguez-Lázaro, 2004. Anaerobic Growth of Bacillus mojavensis and Bacillus subtilis Requires Deoxyribonucleosides or DNA. Martha J. Folmsbee, 2004.Bacillus mojavensis strains JF-2 (ATCC 39307), ROB2, and ABO21191T and Bacillus subtilis strains 168 (ATCC 23857) and ATCC 12332 required four deoxyribonucleosides or DNA for growth under strict anaerobic conditions . Bacillus licheniformis strains L89-11 and L87-11, Bacillus sonorensis strain TG8-8, and Bacillus cereus (ATCC 14579) did not require DNA for anaerobic growth . The requirement for the deoxyribonucleosides or DNA did not occur under aerobic growth conditions . The addition of a mixture of five nucleic acid bases, four ribonucleotides, or four ribonucleosides to the basal medium did not replace the requirement of B . mojavensis JF-2 for the four deoxyribonucleosides . However, the addition of salmon sperm DNA, herring sperm DNA, Escherichia coli DNA, or synthetic DNA (single or double stranded) to the basal medium supported anaerobic growth . The addition of four deoxyribonucleosides to the basal medium allowed aerobic growth of B . mojavensis JF-2 in the presence of hydroxyurea . B . mojavensis did not grow in DNA-supplemented basal medium that lacked sucrose as the energy source . These data provide strong evidence that externally supplied deoxyribonucleosides can be used to maintain a balanced deoxyribonucleotide pool for DNA synthesis and suggest that ribonucleotide reductases may not be essential to the bacterial cell cycle nor are they necessarily part of a minimal bacterial genome . The Genome Sequence of Yersinia pestis Bacteriophage  A1122 Reveals an Intimate History with the Coliphage T3 and T7 Genomes.Emilio Garcia, 2003.The genome sequence of bacteriophage A1122 has been determined .
A1122 grows on almost all isolates of Yersinia pestis and is used by the Centers for Disease Control and Prevention as a diagnostic agent for the causative agent of plague .
A1122 is very closely related to coliphage T7; the two genomes are colinear, and the genome-wide level of nucleotide identity is about 89% . However, a quarter of the
A1122 genome, one that includes about half of the morphogenetic and maturation functions, is significantly more closely related to coliphage T3 than to T7 . It is proposed that the yersiniophage
A1122 recombined with a close relative of the Y . enterocolitica phage
YeO3-12 to yield progeny phages, one of which became the classic T3 coliphage of Demerec and Fano (M . Demerec and U . Fano, Genetics 30:119-136, 1945) .
Cooperation between Lactococcus lactis and Nonstarter Lactobacilli in the Formation of Cheese Aroma from Amino Acids. Agnieszka Kieronczyk, 2003.In Gouda and Cheddar type cheeses the amino acid conversion to aroma compounds, which is a major process for aroma formation, is essentially due to lactic acid bacteria (LAB) . In order to evaluate the respective role of starter and nonstarter LAB and their interactions in cheese flavor formation, we compared the catabolism of phenylalanine, leucine, and methionine by single strains and strain mixtures of Lactococcus lactis subsp . cremoris NCDO763 and three mesophilic lactobacilli . Amino acid catabolism was studied in vitro at pH 5.5, by using radiolabeled amino acids as tracers . In the presence of  -ketoglutarate, which is essential for amino acid transamination, the lactobacillus strains degraded less amino acids than L . lactis subsp . cremoris NCDO763, and produced mainly nonaromatic metabolites . L . lactis subsp . cremoris NCDO763 produced mainly the carboxylic acids, which are important compounds for cheese aroma . However, in the reaction mixture containing glutamate, only two lactobacillus strains degraded amino acids significantly . This was due to their glutamate dehydrogenase (GDH) activity, which produced
-ketoglutarate from glutamate . The combination of each of the GDH-positive lactobacilli with L . lactis subsp . cremoris NCDO763 had a beneficial effect on the aroma formation . Lactobacilli initiated the conversion of amino acids by transforming them mainly to keto and hydroxy acids, which subsequently were converted to carboxylic acids by the Lactococcus strain . Therefore, we think that such cooperation between starter L . lactis and GDH-positive lactobacilli can stimulate flavor development in cheese .
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