Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Peromyscus”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,477 records · Page 82Linked to original sources
PubMedDate not supplied

Using remotely sensed data to identify areas at risk for hantavirus pulmonary syndrome.

The 1993 U.S. hantavirus pulmonary syndrome (HPS) outbreak was attributed to environmental conditions and increased rodent populations caused by unusual weather in 1991- 92. In a case-control study to test this hypothesis, we estimated precipitation at 28 HPS and 170 control sites during the springs of 1992 and 1993 and compared it with precipitation during the previous 6 years by using rainfall patterns at 196 weather stations. We also used elevation data and Landsat Thematic Mapper satellite imagery collected the year before the outbreak to estimate HPS risk by logistic regression analysis. Rainfall at case sites was not higher during 1992-93 than in previous years. However, elevation, as well as satellite data, showed association between environmental conditions and HPS risk the following year. Repeated analysis using satellite imagery from 1995 showed substantial decrease in medium- to high-risk areas. Only one case of HPS was identified in 1996.

Animals↗
PubMed2001

Reduction in DNA binding activity of the transcription factor Pax-5a in B lymphocytes of aged mice.

Aging has been associated with intrinsic changes of the humoral immune response, which may lead to an increased occurrence of autoimmune disorders and pathogenic susceptibility. The transcription factor Pax-5 is a key regulator of B cell development. Pax-5a/B cell-specific activator protein and an alternatively spliced isoform, Pax-5d, may have opposing functions in transcriptional regulation due to the lack of a transactivation domain in Pax-5d. To study B cell-specific changes that occur during the aging process, we investigated expression patterns of Pax-5a and 5d in mature B cells of young and aged mice. RNase protection assays showed a similar transcriptional pattern for both age groups that indicates that aging has no affect on transcription initiation or alternative splicing for either isoform. In contrast, a significant reduction in the DNA binding activity of Pax-5a but not Pax-5d protein was observed in aged B cells in vitro, while Western blot analyses showed that similar levels of Pax-5a and 5d proteins were present in both age groups. The observed decrease in Pax-5a binding activity correlated with changes in expression of two Pax-5 target genes in aged B cells. Expression of the Ig J chain and the secreted form of Ig mu, which are both known to be suppressed by Pax-5a in mature B cells, were increased in B cells of aged mice. Together, our studies suggest that changes associated with the aging phenotype cause posttranslational modification(s) of Pax-5a but not Pax-5d, which may lead to an abnormal B cell phenotype in aged mice, associated with elevated levels of J chain, and secretion of IgM.

Aging↗
PubMed2002

Hyperconservation of the putative antigen recognition site of the MHC class I-b molecule TL in the subfamily Murinae: evidence that thymus leukemia antigen is an ancient mammalian gene.

"Classical" MHC class I (I-a) genes are extraordinarily polymorphic, but "nonclassical" MHC class I (I-b) genes are monomorphic or oligomorphic. Although diversifying (positive) Darwinian selection is thought to explain the origin and maintenance of MHC class I-a polymorphisms, genetic mechanisms underlying MHC class I-b evolution are uncertain. In one extreme model, MHC class I-b loci are derived by gene duplication from MHC class I-a alleles but rapidly drift into functional obsolescence and are eventually deleted. In this model, extant MHC class I-b genes are relatively young, tend to be dysfunctional or pseudogenic, and orthologies are restricted to close taxa. An alternative model proposed that the mouse MHC class I-b gene thymus leukemia Ag (TL) arose approximately 100 million years ago, near the time of the mammalian radiation. To determine the mode of evolution of TL, we cloned TL from genomic DNA of 11 species of subfamily Murinae: Every sample we tested contained TL, suggesting this molecule has been maintained throughout murine evolution. The sequence similarity of TL orthologs ranged from 85-99% and was inversely proportional to taxonomic distance. The sequences showed high conservation throughout the entire extracellular domains with exceptional conservation in the putative Ag recognition site. Our results strengthen the hypotheses that TL has evolved a specialized function and represents an ancient MHC class I-b gene.

Amino Acid Sequence↗
PubMed1985

Mice as reservoirs of the Lyme disease spirochete.

In evaluating the white-footed mouse as a reservoir host for the Lyme disease spirochete, we compared spirochete infection in vector ticks (Ixodes dammini) having different histories of attachment to these mice, estimated their relative importance as hosts for immature I. dammini and compared the seasonality of tick activity and spirochetemia in mice. Infection in trapped white-footed mice appears to be universal. Prevalence of spirochetal infection in I. dammini correlates with frequency of attachment to mice, and in mice, with the season of vector activity. The relative abundance of this mouse makes it numerically the most important host for I. dammini. Most immature I. dammini appear to attach to white-footed mice. Taken together, these considerations demonstrate that the white-footed mouse serves as reservoir for the Lyme disease spirochete in coastal Massachusetts.

Animals↗
PubMed1990

Susceptibility of the western fence lizard (Sceloporus occidentalis) to the Lyme borreliosis spirochete (Borrelia burgdorferi).

Attempts to infect juvenile and adult western fence lizards (Sceloporus occidentalis) with the Lyme borreliosis spirochete (Borrelia burgdorferi) were largely unsuccessful. Spirochetes could not be isolated from the blood and various tissues of 14 lizards 21-32 days after they had been inoculated ip (n = 8) or sc (n = 6) with 10(6) or 10(8) B. burgdorferi representing 3 tick isolates, although 1 lizard apparently developed a transitory spirochetemia lasting 2 days. Similarly, spirochetes could not be detected in the blood or tissues of 5 lizards fed upon by 2- greater than 8 infected larvae or nymphs of the western black-legged tick (Ixodes pacificus). Sixty-five blood samples from 59 lizards in an endemic area and various tissues from 20 of the same lizards were also assayed for B. burgdorferi with negative results. The implications of these findings for the maintenance of this spirochete in natural foci are discussed.

Animals↗
PubMed1996

Ecology of Jamestown Canyon virus (Bunyaviridae: California serogroup) in coastal California.

This paper reports the first isolation of Jamestown Canyon (JC) virus from coastal California and the results of tests for antibody to JC virus in mammals living in coastal California. The virus isolation was made from a pool of 50 Aedes dorsalis females collected as adults from Morro Bay, San Luis Obispo County, California. The virus isolate was identified by two-way plaque reduction-serum dilution neutralization tests done in Vero cell cultures. Sera from the mammals were tested for antibody to JC virus by a plaque-reduction serum dilution neutralization method. A high prevalence of JC virus-specific antibody was found in horses and cattle sampled from Morro Bay. This finding is additional evidence for the presence of a virus antigenically identical or closely related to JC virus in Morro Bay and indicates that the vectors of the virus in Morro Bay feed on large mammals. A high prevalence of virus-specific antibody was also found in horses sampled from Marin and San Diego counties. This finding suggests that viruses antigenically identical or closely related to JC virus are geographically widespread in coastal California.

Aedes↗
PubMed1997

Patterns of association with host and habitat: antibody reactive with Sin Nombre virus in small mammals in the major biotic communities of the southwestern United States.

The distribution and prevalence of antibody reactive with Sin Nombre virus were determined in mammals in biotic communities of the southwestern United States. Small mammals (n = 3,069) of 69 species were trapped in nine communities from lower Sonoran desert to alpine tundra. Antibody was found in rodents from all communities (overall prevalence = 6.3%); prevalence was lowest at the altitudinal and climatic extremes (0.4% in desert and 2.0% in alpine tundra). Antibody occurred in 11% of 928 deer mice, 20% of 355 brush mice, 23% of 35 western harvest mice, and 12% of 24 Mexican voles. No infected deer mice were found in desert habitat; prevalence varied from 4% in chaparral to 17% in pinyon-juniper. Brush mice were frequently infected in chaparral and montane forest (25%). Seropositivity was higher in males and in heavier animals, suggesting horizontal transmission among adult males. Decreasing prevalence with age among the youngest deer mice suggests that infected dams confer passive immunity to pups.

Altitude↗
PubMed1992

The red-tailed hawk, Buteo jamaicensis, a native definitive host of Frenkelia microti (Apicomplexa) in North America.

Oral inoculation of prairie voles, Microtus ochrogaster, with coccidian sporocysts isolated from the feces of a red-tailed hawk, Buteo jamaicensis, in Kansas, USA, resulted in formation of Frenkelia microti (Apicomplexa: Sarcocystidae) tissue cysts in the brains of the voles. Five additional isolates of morphologically similar sporocysts collected from red-tailed hawks or other Buteo spp. in Kansas failed to result in detectable infections in rodents. These results are the first to verify that red-tailed hawks are natural definitive host in North America for F. microti.

Animals↗
PubMed1994

Modifications of a cholinesterase method for determination of erythrocyte cholinesterase activity in wild mammals.

A method to determine erythrocyte cholinesterase (ChE) activity was modified for use in wild mammals. Erythrocyte ChE of California voles (Microtus californicus) was primarily acetylcholinesterase (AChE), which was similar to the brain and unlike plasma which was primarily butyrylcholinesterase (BChE). Triplicate erythrocyte AChE analyses from individual animals of several species of wild rodents revealed a mean coefficient of variation of 8.7% (SD = 4.3%). Erythrocyte ChE activity of several wild mammals of California revealed that mule deer (Odocoileus hemionus) had the highest erythrocyte AChE activity (1,514.5 mU/ml) and dusky-footed woodrats (Neotoma fuscipes) had the lowest activity (524.3 mU/ml). No ChE activity was found in erythrocytes of several species of birds and fish.

Animals↗
PubMed1997

Plague in a complex of white-tailed prairie dogs and associated small mammals in Wyoming.

Fleas were collected from white-tailed prairie dogs (Cynomys leucurus) and other small mammals trapped on six grids during a field study near Meeteetse (Wyoming, USA) in 1989 and 1990 to investigate the dynamics of plague in this rodent population. Fleas were identified and tested for Yersinia pestis by mouse inoculation. Yersinia pestis-positive fleas were found on prairie dogs and in their burrows. Flea species on prairie dogs changed from spring to late summer. White-tailed prairie dog numbers were significantly lower in the presence of Y. pestis-positive fleas; however, affected populations generally recovered 1 to 2 yr following absence of detectable plague. Grids where recovery occurred had a high proportion of juvenile male prairie dogs. Eighteen flea species were identified on small mammals, six of which were infected with Y. pestis. Some flea species were associated with a particular small mammal species, while others were found on a broad range of host species. Flea species most important in the potential interchange of Y. pestis between associated small mammals and white-tailed prairie dogs were Oropsylla tuberculata cynomuris, Oropsylla idahoensis, and Oropsylla labis. Plague cycled through the white-tailed prairie dog complex in an unpredictable manner. Each summer the complex was a mixture of colonies variously impacted by plague: some were declining, some were unaffected by plague, and others were recovering from plague population declines. These data provide insight into the dynamics of plague in white-tailed prairie dog complexes, but predicting movement of plague is not yet possible and the role of associated mammals in maintenance of plague is not understood.

Animals↗
PubMed2000

Effects of bleeding nonanesthetized wild rodents on handling mortality and subsequent recapture.

Handling mortality and recapture rates of wild rodents that were bled from the retroorbital capillary plexus without anesthesia were assessed. In 9,670 captures of seven species of rodents from 1994 through 1998, we found no difference in handling mortality in bled mice compared to those from trapping grids where mice were not bled. Recapture rates of rodents on control (non-bleeding grids) and rodents on bleeding grids was not significantly different for any species. We conclude that bleeding in the absence of anesthesia does not affect immediate mortality or subsequent recapture.

Anesthesia↗
PubMed1999

Learning to cope with biting flies: rapid NMDA-mediated acquisition of conditioned analgesia.

A 30-min exposure to intact biting flies (stable flies) induced an opioid-mediated analgesia in fly-naive male deer mice, whereas exposure to either altered biting flies whose biting mouthparts were removed or nonbiting house flies had no significant effects. However, mice that were previously exposed to intact stable flies for 30 min exhibited significant analgesia when exposed 24-168 hr later to stable flies whose biting parts were removed, but not to nonbiting house flies. Administration of the specific N-methyl-D-aspartate (NMDA) antagonist NPC 12626 to fly-naive mice before exposure to intact flies, although not significantly reducing the analgesic response, blocked the subsequent conditioned analgesia. Naloxone, which blocked the intact biting fly-induced analgesia, did not alter the acquisition of the conditioned analgesic response to the altered stable flies. This demonstrates an NMDA-mediated acquisition of conditioned analgesia to a natural aversive stimulus.

Adaptation, Physiological↗
PubMed2000

The Dlk1 and Gtl2 genes are linked and reciprocally imprinted.

Genes subject to genomic imprinting exist in large chromosomal domains, probably reflecting coordinate regulation of the genes within a cluster. Such regulation has been demonstrated for the H19, Igf2, and Ins2 genes that share a bifunctional imprinting control region. We have identified the Dlk1 gene as a new imprinted gene that is paternally expressed. Furthermore, we show that Dlk1 is tightly linked to the maternally expressed Gtl2 gene. Dlk1 and Gtl2 are coexpressed and respond in a reciprocal manner to loss of DNA methylation. These genes are likely to represent a new example of coordinated imprinting of linked genes.

Animals↗
PubMed2000

Development of spontaneous stereotyped behavior in deer mice: effects of early and late exposure to a more complex environment.

Abnormal repetitive behaviors such as stereotypies are associated with neurodevelopmental disorders and are often observed under conditions of environmental restriction, particularly early in development. Few studies, however, have systematically assessed the effects of environmental enrichment and almost no information is available as to whether a sensitive period exists for such enrichment effects. We hypothesized that spontaneous stereotypies exhibited by deer mice housed under standard laboratory conditions were the result of environmental restriction and that a sensitive period exists for the development/prevention of stereotypies. Exposure to a more complex environment early in the post-weaning period resulted in substantially less stereotypy in the complex environment. Importantly, this outcome was maintained even after mice were housed in standard cages for an identical period of time. Later exposure to the more complex environment also resulted in significantly lower levels of stereotypy compared to controls. These effects were observed in the experimental housing condition as well as in a standard test context. The effects of early and late enrichment support the importance of environmental restriction in the genesis of stereotype and provide support for the efficacy of early and late enrichment in the prevention of stereotypies.

Age Factors↗
PubMed2001

Hantavirus pulmonary syndrome--Vermont, 2000.

In 1993, an outbreak of an unexplained pulmonary illness occurred in the southwestern United States. This outbreak led to the first description of hantavirus pulmonary syndrome (HPS), a rodentborne hantaviral infection. Hantaviruses have been found in rodents in rural areas throughout the United States, but most infection has occurred in the southwest. This report describes the first HPS case in Vermont and underscores the importance of preventing exposure to peridomestic rodents and recognizing the signs and symptoms of HPS.

Animals↗