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H R Jensen

Publications and source records attributed to H R Jensen.

3 recordsLinked to original sources
PubMed2006

The effect of a synergistic concentration of a Piper nigrum extract used in conjunction with pyrethrum upon gene expression in Drosophila melanogaster.

An ethyl acetate extract of Piper nigrum L. (Piperaceae) peppercorns was tested as a synergist for the botanical insecticide pyrethrum. A high synergist ratio of 11.6 against Drosophila melanogaster was obtained for the combination of pyrethrum supplemented with P. nigrum. The effect of this combination was investigated using cDNA microarray analysis of gene expression profiles in D. melanogaster. Treatment of D. melanogaster with pyrethrum alone resulted in a large number of differentially expressed genes, principally associated with stress responses. Seven genes were identified as being commonly expressed in D. melanogaster treated with at least two of the following treatments: P. nigrum, pyrethrum or P. nigrum plus pyrethrum. These are likely implicated in Drosophila defence responses to toxins.

Animals↗
PubMed1978

Improved methods for detecting enteric viruses in oysters.

New and improved methods for concentrating enteroviruses, reoviruses, and adenoviruses from oysters have been developed and evaluated. Viruses are efficiently adsorbed to homogenized oyster meat by adjusting the homogenate to pH 5.0 and a conductivity of less than or equal to 2,000 mg of NaCl per liter. After low-speed centrifugation, the virus-free supernatant is discarded and the viruses are eluted from the sedimented oyster solids with pH 7.5 glycine-NaCl having a conductivity of 8,000 mg of NaCl per liter. The oyster solids are removed by low-speed centrifugation and filtration, and the viruses in the filtered supernatant are concentrated to a small volume by either ultrafiltration or acid precipitation at pH 4.5. The concentrate is treated with antibiotics and inoculated into cell cultures for virus isolation and quantitation. When these methods were tested with oysters experimentally contaminated with polioviruses, reoviruses, and adenoviruses, recovery efficiencies averaged about 46%. With the exception of virus assay and quantitation, these methods are simple and inexpensive enough to be done in typical shellfish microbiology laboratories.

Adenoviridae↗