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D W Janssen

Publications and source records attributed to D W Janssen.

6 recordsLinked to original sources
PubMed2001

STR primer concordance study.

Over 1500 population database samples comprising African Americans, Caucasians, Hispanics, Native Americans, Chamorros and Filipinos were typed using the PowerPlex 16 and the Profiler Plus/COfiler kits. Except for the D8S1179 locus in Chamorros and Filipinos from Guam, there were eight examples in which a typing difference due to allele dropout was observed. At the D8S1179 locus in the population samples from Guam, there were 13 examples of allele dropout observed when using the Profiler Plus kit. The data support that the primers used in the PowerPlex 16, Profiler Plus, and COfiler kits are reliable for typing reference samples that are for use in CODIS. In addition, allele frequency databases have been established for the STR loci Penta D and Penta E. Both loci are highly polymorphic.

Alleles↗
PubMed1973

Influence of milk components on the injury, repair of injury, and death of Salmonella anatum cells subjected to freezing and thawing.

Fast freezing and slow thawing Salmonella anatum cells in various milk components inactivated from 20 to 98% of the cells and damaged 40 to 90% of the cells surviving the treatments. Injured cells failed to form colonies on a selective medium (xylose-lysine-peptone agar with 0.2% sodium deoxycholate) but did form colonies on a nonselective plating medium (xylose-lysine-peptone agar). The major milk components-lactose, milk salts, casein, and whey proteins-influenced the extent of injury, repair of injury, and death. The percentages of cells injured and inactivated were decreased by the presence of any milk components except whey proteins. Also, repair of injury was promoted by the presence of each milk component except whey proteins, which in contrast inhibited repair. Phosphate was the most influential milk salts component that protected the cells and promoted repair of injury. These individual milk components may have decreased the extent of freezing-induced death and cellular damage by stabilizing the S. anatum cell envelope.

Animals↗
PubMed1972

Characterization of the repair of injury induced by freezing Salmonella anatum.

Fast freezing and slow thawing of Salmonella anatum cells suspended in water resulted in injury of more than 90% of the cells that survived the treatment. The injured cells failed to form colonies on the selective medium (xyloselysine-peptone-agar with 0.2% sodium deoxycholate) but did form colonies on a nonselective (xylose-lysine-peptone-agar) plating medium. In Tryptic soy plus 0.3% yeast extract broth or minimal broth, most of the injured cells repaired within 1 to 2 hr at 25 C. Tryptic soy plus yeast extract broth supported repair to a greater extent than minimal broth. Phosphate or citrate at concentrations found in minimal broth supported repair of some cells. MgSO(4), when present with inorganic phosphate or citrate or both, increased the extent of repair. The repair process in the presence of phosphate was not prevented by actinomycin D, chloramphenicol, and D-cycloserine, but was prevented by cyanide and 2,4-dinitrophenol (only at pH 6). This suggested that the repair process might involve energy metabolism in the form of adenosine triphosphate. The freeze-injured cells were highly sensitive to lysozyme, whereas unfrozen fresh cells were not. In the presence of phosphate or minimal broth this sensitivity was greatly reduced. This suggested that, at least in some of the cells, the injury involved the lipopolysaccharide of the cell wall and adenosine triphosphate synthesis was required for repair.

Adenosine Triphosphate↗