Publications

reduced prevalence of the lucké renal adenocarcinoma in populations of rana pipiens in minnesota.	northern leopard frogs (rana pipiens) afflicted with the lucké renal adenocarcinoma virtually disappeared from minnesota in the autumn of 1977. frogs from four sites in minnesota counties (polk, otter tail, kandiyohi, and scott) with a previously high prevalence of lucké renal tumor were studied. in the past decade, prevalence averaged 4.2% in 29 collections (total, 1,870 frogs). no tumors were detected in 685 frogs autopsied in the autumn of 1977 by the method of previous studies. frog collecti ...	1966	224239
aeromonas hydrophila in wild-caught frogs and tadpoles (rana pipiens) in minnesota.	frogs and tadpoles were captured at 14 sites in and near minnesota during 1978-79 and nearly all appeared healthy. aeromonas hydrophila was isolated from 94 of 294 (32%) juvenile and adult frogs and from 66 of 104 (63%) tadpoles. of the isolates from frogs and tadpoles respectively, 68% and 47% were from the intestine only, 12% and 32% were from the intestine and the other sites, and 20% and 21% were from extraintestinal sites only. isolations were more frequent from frogs collected in march-jun ...	1981	6972468
enterobacteriaceae and aeromonas hydrophila in minnesota frogs and tadpoles (rana pipiens).	in 222 rana pipiens frogs and 34 tadpoles captured in and near minnesota, aeromonas hydrophila and 29 species of enterobacteriaceae, including yersinia enterocolitica and salmonella arizonae, were isolated from intestines. the prevalence of members of the family enterobacteriaceae was lowest in frogs captured in early spring and highest in frogs captured in late summer.	1983	6607034
increased prevalence of mature females bearing pigmented oocytes from populations of minnesota rana pipiens.	mature female leopard frogs, rana pipiens, collected from several sites in minnesota from 1967 through 1977, were examined for the presence of pigmented oocytes. an increase in the percent of mature females with pigmented oocytes was observed in the frogs captured in 1977 compared to those captured earlier. coincident with the increase in prevalence of females with pigmented oocytes, there was a decline in abundance of the frogs.	1992	312362
hind limb malformations in free-living northern leopard frogs (rana pipiens) from maine, minnesota, and vermont suggest multiple etiologies.	reports of malformed frogs have increased throughout the north american continent in recent years. most of the observed malformations have involved the hind limbs. the goal of this study was to accurately characterize the hind limb malformations in wild frogs as an important step toward understanding the possible etiologies.	2000	10935979
a regional survey of malformed frogs in minnesota (usa) (minnesota malformed frogs).	in late 1995, school children discovered malformed frogs in a south central minnesota pond. press coverage resulted in numerous citizen reports of frog malformation across minnesota in 1996. after some initial site investigation, 3 affected frog sites and 4 nearby reference sites were selected for more detailed evaluation. field biologists made 89 visits to study sites beginning spring 1997 through fall 1999 to examine the number and type of frog malformations. over 5,100 leopard frogs (rana pip ...	2003	12602621
prevalence of skeletal and eye malformations in frogs from north-central united states: estimations based on collections from randomly selected sites.	skeletal malformation rates for several frog species were determined in a set of randomly selected wetlands in the north-central usa over three consecutive years. in 1998, 62 sites yielded 389 metamorphic frogs, nine (2.3%) of which had skeletal or eye malformations. a subset of the original sites was surveyed in the following 2 yr. in 1999, 1,085 metamorphic frogs were collected from 36 sites and 17 (1.6%) had skeletal or eye malformations, while in 2000, examination of 1,131 metamorphs yielded ...	2003	14567211
assessing the toxicity and teratogenicity of pond water in north-central minnesota to amphibians.	incidence of amphibian deformities have increased in recent years, especially in the northern region of the united states. while many factors have been proposed as being responsible for generating deformities (e.g., contaminants, ultraviolet radiation [uv], parasites), no single cause has been definitively established.	2004	15341313
variations in the expressed antimicrobial peptide repertoire of northern leopard frog (rana pipiens) populations suggest intraspecies differences in resistance to pathogens.	the northern leopard frog (rana pipiens or lithobates pipiens) is historically found in most of the provinces of canada and the northern and southwest states of the united states. in the last 50 years, populations have suffered significant losses, especially in the western regions of the species range. using a peptidomics approach, we show that the pattern of expressed antimicrobial skin peptides of frogs from three geographically separated populations are distinct, and we report the presence of ...	2009	19622371
indicators of the statuses of amphibian populations and their potential for exposure to atrazine in four midwestern u.s. conservation areas.	extensive corn production in the midwestern united states has physically eliminated or fragmented vast areas of historical amphibian habitat. midwestern corn farmers also apply large quantities of fertilizers and herbicides, which can cause direct and indirect effects on amphibians. limited field research regarding the statuses of midwestern amphibian populations near areas of corn production has left resource managers, conservation planners, and other stakeholders needing more information to im ...	2014	25216249