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At least 19 recordsLinked to original sources
PubMed1982

Leptospirosis in Rattus norvegicus and Rattus rattus in Israel.

Leptospires were isolated from 21.2% of Rattus norvegicus (the brown rat) and 9.9% of Rattus rattus trapped in a survey of urban and rural areas in Israel. Microagglutination antibodies were found in sera of 9.4 and 8.1% of these rats, respectively. The 191 strains isolated belonged to six serogroups: Leptospira icterohaemorrhagiae (169), L. bataviae (3), L. semeranga (1), L andamana (1) and L. ballum (1) from R. norvegicus and L. ballum (13) and L. hebdomadis (3) from R. rattus. No significant differences were found between the infection rate of mature male and female brown rats, but all six strains isolated from young animals were obtained from male rats. Two factors influence the rat of Leptospira infection among urban brown rats: the age of the animals and the area in which they are trapped. Adult brown rats trapped in a newly infected area showed a considerably higher level of contamination (61.8%) than those trapped in areas where the infection had persisted for many years (22.8%). Young rats showed a low degree of contamination in both the old foci (5.7%) and the new foci (2.2%). New and highly infected areas were found during this survey in Tel Aviv (Carmel market) and its neighboring cities of Holon, Ramat Gan and Givatayim.

Agglutination Tests↗
PubMed1981

Intra- and interspecific variation of the mitochondrial genome in Rattus norvegicus and Rattus rattus: restriction enzyme analysis of variant mitochondrial DNA molecules and their evolutionary relationships.

Restriction endonuclease analysis has revealed extensive mtDNA polymorphism in two species of rats, Rattus rattus and Rattus norvegicus. Sequence divergence values for the eight detected R. norvegicus variants range from 0.2% to 1.8% and for the eight R. rattus variants, from 0.2% to 9.6%. Three of the most closely related R. norvegicus mtDNA's appear to differ by deletions/insertions of about 4 base pairs apiece. Restriction sites for seven enzymes have been mapped for 11 of these variants. The 31 intraspecific and 41 interspecific variant sites appear to be evenly distributed on the mtDNA molecule outside of the rRNA cistrons. The location of sites present in all the DNAs suggests that the rRNA genes and possibly the light strand origin of replication may be more highly evolutionarily conserved than other parts of the molecule. The sequence divergences among the mtDNAs of animals whose geographic origins are separated by major barriers, such as oceans, were significantly greater than those among animals found within large land masses, such as the continental United States. Dendrograms (phenograms), which have been constructed to depict the relationships among the various DNAs, indicate that East Asian members of the R. rattus species are more closely related to American rats of this species than to other Asian R. rattus animals from Sri Lanka. Moreover, it appears that R. norvegicus comprises a group taxonomically distinct from any of the R. rattus subspecies.

Animals↗
PubMed2002

Independent integration of rodent identifier (ID) elements into orthologous sites of some RT6 alleles of Rattus norvegicus and Rattus rattus.

The two alleles of the rat T-cell differentiation alloantigen RT6 are highly divergent and their expression is distinctively regulated. While the majority of T cells of RT6a/RT6b heterozygous laboratory rats (Rattus norvegicus) expresses both alleles, a subpopulation expresses only RT6b. To identify cis-regulatory elements that potentially control monoallelic expression, we compared the sequences of both alleles. A striking difference is the presence or absence of a rodent identifier (ID) sequence in intron 7. All investigated inbred RT6a rat strains (n=7) had this integration, while it was absent in all investigated RT6b rats (n=9). An ID element was also identified at precisely the same integration site in one RT6 allele of the closely related species Rattus rattus. The ID elements of both species showed nucleotide substitutions characteristic of different subfamilies, and their flanking repeats differed in length, indicating that two independent integration events had occurred into the same site adjacent to a mammalianwide interspersed repeat. Analysis of the surrounding sequences did not disclose any motifs to explain preferential integration into one allele. Our data indicate that the RT6 alleles diverged about 1 myr ago and that the ID element integrated into the RT6a locus soon after this. We have previously shown that DNA methylation plays an important role in regulating monoallelic RT6 expression. The possibility that the ID element in the RT6a allele interferes with the required demethylation process and thus accounts for monoallelic expression is discussed.

ADP Ribose Transferases↗
PubMed1987

Kinetics of bromadiolone, anticoagulant rodenticide, in the Norway rat (Rattus norvegicus).

Rats (Rattus norvegicus) dosed orally with the rodenticide bromadiolone (0.8 and 3 mg/kg) were sacrificed in groups of 4 rats at various times up to 97 hours after administration. Bromadiolone was assayed in plasma, liver and kidney by an HPLC method. The compound disappeared slowly from the organism with a half-life of 25.7 hours for the 0.8 mg/kg dose and 57.5 hours for the 3 mg/kg. Concentrations in liver were rapidly established and were 14- to 46-fold higher than plasma concentrations. 97 hours after 3 mg/kg dose, liver concentrations were about 1.5 micrograms/g. Bromadiolone levels in kidney were slightly higher than those observed in plasma, with a longer half-life.

4-Hydroxycoumarins↗
PubMed1974

Field trials of the rodenticide 5-p-chlorophenyl silatrane against wild rats (Rattus norvegicus Berk.).

Rattus norvegicus infestations on six farmsteads were poisoned with 0.5% 5-p-chlorophenyl silatrane and those on another six with 2.5% zinc phosphide. Both poisons were applied in pinhead oatmeal bait containing also 5% corn oil, after pre-baiting. The result of each treatment was assessed by comparing the take of pre-bait with that of a census bait (wheat) laid after the poisoning.The zinc phosphide treatments were generally more effective than those done with 5-p-chlorophenyl silatrane, but the latter were somewhat detrimentally affected by cautious baiting on the part of one of the operators.The results are discussed and it is concluded that although they indicate that 0.5% 5-p-chlorophenyl silatrane may have approached zinc phosphide in effectiveness under the conditions of the trial, it would in most circumstances be significantly less effective and possibly less safe to use than the latter, well-tried poison.

Administration, Oral↗
PubMed1990

Changes in mating vocalizations over the ejaculatory series in rats (Rattus norvegicus).

Rats (Rattus norvegicus) produce ultrasonic calls during mating. We examined changes in the structure and pattern of such vocalizations over the ejaculatory series. In Experiment 1, vocalizations were recorded from 11 pairs of rats through 3 ejaculatory series and analyzed spectrographically. We classified 4 categories of call by spectral frequency and duration. Calls of low frequency, long duration, and high intensity occurred more often shortly before the ejaculation and were associated with mounting without intromission, a behavior that often occurs shortly before ejaculation. The high-frequency calls did not vary in number across the series. In Experiment 2, vocalizations were recorded from males paired with devocalized females. Males produced all vocalization patterns produced by pairs in Experiment 1. Results suggest that most pre-ejaculatory calls are produced by males and may potentially affect female sexual behavior.

Animals↗
PubMed1992

Sexual free behavior in male rats (Rattus norvegicus).

Male rats (Rattus norvegicus) were given continuous access to estrous female rats for 24 hr each day for 10 days. During the first 12 hr, the rats achieved an average of 10 ejaculations, followed by a 1- to 2-day recovery period with little sexual activity. During the last 7 days, the rats maintained a reasonably stable equilibrium level of 3 ejaculations per day. These occurred predominantly during the dark phase of the diurnal cycle, they frequently occurred in a cluster, and they usually occurred shortly after the introduction of a novel estrous female. Except for quantitative differences, these results are generally consistent with conventional research but systematically extend the generality of the results to the context of the free behavior situation. The availability of sexual activity had no appreciable effect on food and water intake, but it did decrease the amount of running activity.

Animals↗
PubMed2006

[Study on the association between hantavirus infection and Rattus norvegicus].

OBJECTIVE: To further understand the association of hantavirus (HV) harbored and transmitted in wild brown rats. METHODS: Rattus norvegicus (n = 570) were trapped in 10 sites in Beijing. RT-PCR was used to test rodent lung samples for hantavirus infection. Unconditional multivariate logistic regression analysis was performed, with PCR positive as the dependent variable and the characteristics of Rattus norvegicus population as independent variables. RESULTS: The overall HV prevalence in Rattus norvegicus was 9.1% (52/570). Significant association between HV infection in Rattus norvegicus and some biological characteristics of host population was observed. Adult Rattus norvegicus had a higher HV prevalence than juveniles. Males in the reproduction periods and rats with wounds were more likely to be infected with HV than others. CONCLUSION: It was further confirmed that there existed parallel transmission of HV in Rattus norvegicus hosts. Aggression might be the primary mode of HV transmission among male Rattus norvegicus.

Aggression↗
PubMed1996

Antibody responses against Echinococcus multilocularis antigens in naturally infected Rattus norvegicus.

Two Norway rats, Rattus norvegicus, were found to be naturally infected with Echinococcus multilocularis in Japan. One of them was simultaneously infected with at least three different sized metacestodes of Taenia taeniaeformis. These two R. norvegicus rats and another R. norvegicus naturally infected with T. taeniaeformis and Capillaria hepatica were examined to see if they showed any antibody responses against these two cestode parasites with the view to obtaining more information on the importance of rats as the intermediate host for E. multilocularis. These R. norvegicus showed very poor antibody responses against the two cestode species, although the Wistar rats, R. rattus, experimentally infected with a single smaller sized metacestode of T. taeniaeformis showed stronger responses not only against T. taeniaeformis but also against E. multilocularis. Therefore the three R. norvegicus naturally infected with E. multilocularis and/or T. taeniaeformis demonstrated virtually no immune response, at least against these cestodes.

Animals↗