Landscape location affects genetic variation of Canada lynx (Lynx canadensis).

The effect of a population's location on the landscape on genetic variation has been of interest to population genetics for more than half a century. However, most studies do not consider broadscale biogeography when interpreting genetic data. In this study, we propose an operational definition of a peripheral population, and then explore whether peripheral populations of Canada lynx (Lynx canadensis) have less genetic variation than core populations at nine microsatellite loci. We show that peripheral populations of lynx have fewer mean numbers of alleles per population and lower expected heterozygosity. This is surprising, given the lynx's capacity to move long distances, but can be explained by the fact that peripheral populations often have smaller population sizes, limited opportunities for genetic exchange and may be disproportionately affected by ebbs and flows of species' geographical range.

Evaluation of the IDS RapID SS/u system for rapid identification of urinary microorganisms.

The accuracy of a new rapid identification system for common urinary pathogens was compared with that of conventional methods and of miniaturized 18-24-hour identification panels. The rapid system, RapID SS/u (Innovative Diagnostic System Inc., Atlanta, GA) is a non-growth-dependent micro-method that identifies selected gram-negative bacilli, gram-positive cocci, and yeasts in two hours by detection of constitutive enzymes acting on chromogenic substrates. A total of 185 representative clinical urinary isolates were tested, including 24 gram-positive cocci, 140 gram-negative bacilli, and 21 yeasts. Identifications by the rapid system were compared with the ones obtained by reference conventional methods for gram-positive cocci and yeasts. For gram-negative bacilli, identifications were compared with the ones obtained by MicroScan Combo Panel (American MicroScan, Mahwah, NJ), and all discrepancies were resolved by testing with API 20E (Analytab Products, Plainview, NY). Overall, the RapID SS/u system correctly identified to genus 160 of 185 isolates (86.5%). For 14 additional isolates (7.6%) the system provided probability overlap identifications that required further testing. Two (1%) isolates failed to be identified, and nine isolates (4.9%) were misidentified by the system. Discrepancies involved five strains of Citrobacter, one Enterobacter, one Morganella, and one Providencia species. The authors conclude that the RapID SS/u system provided rapid and accurate genus identification of most microorganisms commonly isolated from urine.

Rapid detection of cytomegalovirus in clinical specimens by immunofluorescent staining of shell vial cultures.

A recently described rapid technique for detection of cytomegalovirus (CMV) was evaluated in clinical specimens utilizing indirect immunofluorescent staining (IFA) of shell vial cultures. A total of 266 clinical specimens received for viral isolation were inoculated to commercially available shell vials seeded with human lung fibroblasts (MRC-5), centrifuged at 700 X g for one hour, and stained after 18 hours incubation with monoclonal antibody to CMV early nuclear protein (Biotech Research Laboratories) and fluorescein conjugated goat antimouse IgG (Cappel Laboratories). All specimens were also inoculated to tubes of human lung fibroblasts and observed for cytopathic effect (CPE) for 28 days. Of 54 specimens positive for CMV, 36 were positive by both IFA and CPE, 3 were positive by CPE only, and 15 were positive by IFA only (P less than 0.01 by the chi-square test). Failure to detect CMV associated CPE in 10 of these 15 samples was probably due to concomitant infection with herpes simplex virus or heavy bacterial or fungal contamination. Nine of the 13 patients with IFA-positive CPE-negative specimens had CMV infection documented by other positive cultures. It was concluded that the shell vial IFA rapid technique for detection of CMV is highly specific, more sensitive than conventional isolation, and well suited for application in a clinical virology laboratory.