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At least 19 recordsLinked to original sources
PubMed1984

[Spontaneous and experimental infection of alpine marmots (Marmota marmota) by the North American woodchuck hepatitis virus (Marmota monax). Initial results].

Summer's discovery in 1978 of a DNA virus, very close to human Hepatitis B virus in a woodchuck population in the U.S.A. (Pennsylvania) was a confirmation of the first description made by Snyder at Penrose Research Laboratory (Philadelphia). It was the first animal model of human B hepatitis infection. The comparative study of morphological, ecological and ethological characteristics of the marmot (Marmota marmota) and the woodchuck (Marmota monax) enables an easy distinction between these two species. The natural infection of M. monax by the WHV shows that the woodchuck is a good model for human B hepatitis and should be extended to M. marmota. A sample of 24 marmots caught in the Alpes of Haute-Provence has not revealed any spontaneous infection in these animals by the woodchuck virus. The failure of experimental inoculation of the marmot (24 animals) with the WHV confirms the refractory status of this species (no viremia and very low and short serological response with or without an immunosuppressive treatment). These preliminary results require a confirmation in other animals of different age and geographical region and also by using more specific tests such as molecular hybridization, research on DNA polymerase and direct transfection trials.

Age Factors↗
PubMed1986

The primary structure of the hemoglobin of the European marmot (Marmota marmota marmota, Rodentia).

The hemoglobin of the European marmot Marmota marmota marmota has been found to consist of only one component. In this work, we are presenting its primary structure. The globin chains have been separated by high performance liquid chromatography and the sequences have been determined by automated Edman degradation of the chains and their tryptic peptides, as well as of the peptide obtained by acid hydrolysis of the Asp-Pro bond in the beta-chains. In the alpha-chains we have found 13 and in the beta-chains 34 exchanges compared with the human alpha- and beta-chains, respectively. The amino acids which are substituted in the alpha-chains are not involved in any contacts, whereas in the beta-chains, one exchange involves a heme contact, two alpha 1/beta 1- and one alpha 1/beta 2-contacts. The functional and evolutionary aspects of these findings are discussed.

Amino Acid Sequence↗
PubMed2005

Seasonal 4-year investigation into the role of the alpine marmot (Marmota marmota) as a carrier of zoophilic dermatophytes.

Two hundred and six samples of alpine marmot (Mamota marmota) hair (148 from adults and 58 from young subjects), 102 soil samples from the entrances to the burrows of the above individuals and 20 control specimens (obtained from adjoining areas away from the burrow systems where the rodents are not usually present) were examined from May 1994 to September 1997. Seventy-five isolates belonging to six species of dermatophytes were found in 69 of the 206 hair samples examined (33.5%). Two species were zoophilic, Microsporum canis (7.8%) and Trichophyton mentagrophytes (11.2.%), and four geophilic, Microsporum cookei (2%), M. gypseum (5.8%), Trichophyton ajelloi (3.9%) and T. terrestre (5.8%). The prevalence of each species in the hair samples did not change significantly according to year, season (chi-squared test [limit significance: P <0.05] gives no significant values [P>0.05] both in year and in season comparison) or age/sex (adult versus juvenile: P=0.1; male versus female: P=0.8) of the marmot. Twenty-three of the 102 soil samples (22.5%) were positive for dermatophytes found in the hair of marmots from the same burrow systems. Five of the 20 control soil samples (25%) were positive for dermatophytes. One isolate of M. gypseum, three of T. terrestre and one of T. mentagrophytes were obtained. Compared with other free-ranging rodent hosts studied in Europe, this mycoflora is characterized by the presence and relatively high prevalence of M. canis, frequently reported in symptomatic and asymptomatic cats, dogs and fur animals. M. canis has not been isolated in other rodents in the wild. However, it has recently been reported in asymptomatic foxes (Vulpes vulpes) from northern Italy. The close link between V vulpes and M. marmota, with the former representing the most important mammal predator of the latter in the Alps (only a fraction of the predator's attacks result in the death of the rodent) may have favoured the adaptation of M. canis to this rodent host. The stable character of the M. canis/M. marmota relationship (no seasonally or annually related difference in the prevalence of this dermatophyte has been found) suggests the inclusion of the alpine marmot in the reservoir of this zoophilic pathogenic agent. In this situation, hibernation in labyrinthine burrow systems, where temperature and moisture ranges are quite uniform the whole year round, may favour the viability of M. canis arthroconidia, whose survival in mountain habitat might otherwise be compromised. This seems to be confirmed by the fact that the fungus has never been found in the control samples collected at a distance of 300 m from the outer edge of the sampled burrow systems.

Animals↗
PubMed2002

Seasonal changes in morphology and function of the gastrointestinal tract of free-living alpine marmots ( Marmota marmota).

The gastrointestinal tracts of 76 free-living alpine marmots ( Marmota marmota) shot during a population control program in Switzerland were collected and analysed for patterns of change in morphology and function over the period from emergence from hibernation in April to just before re-entry into hibernation in September. Between first emergence and mid-summer (July) the fresh tissue mass of the stomach increased by 105%, the small intestine by 259% (among the largest recorded for a mammal), caecum by 185%, proximal colon by 138%, and distal colon by 144%. Mitotic activity was greatest in the small intestine; the mitotic index was high (40%) compared with indexes in the stomach and hindgut (approximately 4%) even at emergence, and increased to approximately 60% by mid-summer. Microbial activity in the caecum was also significant at emergence. The stomach (length) and caecum (length and fresh mass) increased in response to ingested food earlier than did the small intestine. Between mid-summer and September there were decreases in small intestinal tissue mass and mitotic activity. It is concluded that the gastrointestinal tract of alpine marmots probably continues to function throughout hibernation at a low level, with a mid-winter trough as part of an endogenous circannual rhythm. However, after emergence in spring, increases in size and activity of the tract appear to be a response to ingested food rather than to an endogenous signal. The early signs of down-regulation of the small intestine before re-entry into hibernation, together with its delayed up-regulation in response to food in spring, are consistent with the high costs of maintaining this section of the digestive system.

Animals↗
PubMed2004

Seasonal changes in serum metabolites in free-ranging alpine marmots (Marmota marmota).

Circannual changes in serum parameters and body mass were studied in free-ranging Marmota marmota that had been shot in Switzerland (Grisons) for management reasons in May, July, and September of 1995, 1996, and 1997; and in April 1996. Markers of lipid (triglycerides, cholesterol), protein (total protein, urea-nitrogen) and mineral (calcium, inorganic phosphate) metabolism were evaluated in 111 haemolysis-free serum samples; the effects of sex, age, reproductive status, season and year were tested. Mean body mass was higher in adult males than in adult females in July and September, and serum cholesterol concentrations were lower in adult males in May. Pregnant females had lower concentrations of total protein than non-pregnant females, and triglyceride concentrations were negatively correlated with the number of uterine ampullae. Inorganic phosphate decreased and total protein increased with age. In adults, triglycerides, cholesterol and urea-nitrogen increased mainly from May to July and decreased between September and May. Total protein, calcium and phosphate did not change throughout the year. This suggests that, during the active season, ingested lipids and amino acids were utilised for metabolic needs or lipid storage, while in winter, lipids were catabolised and protein was spared. Quantitative differences between years, observed for triglycerides and total protein during the active season, were probably due to different climatic conditions in each year.

Age Factors↗
PubMed1978

Survey of keratinophilic fungi in Alpine marmot (Marmota marmota) burrow soil and in adjoining soils.

Soil samples from 127 marmot (Marmota marmota) burrows were examined for keratinophilic fungi along with 48 soil samples from adjoining areas. The occurrence of keratinophilic fungi (especially Microsporum gypseum) was significantly higher in burrow soil. A review of the literature and our results support the hypothesis that the "animalization" (i.e. the enrichment of soil with hairs, crusts and other organic matters) of the environment may create conditions suitable for the growth of keratinophilic fungi. The presence of keratinophilic fungi in alpine mountain soil was noted for the first time.

Animals↗
PubMed1994

Low genetic variability in a natural alpine marmot population (Marmota marmota, Sciuridae) revealed by DNA fingerprinting.

Genetic heterogeneity is usually considered an important factor for the viability of a population, yet there are cases in which populations sustain themselves despite virtual homozygosity. A prior step to studying the effects of such low levels of genetic variability can be the analysis of its causes. We analysed a population of the highly social alpine marmot (Marmota marmota, Sciuridae) by multilocus DNA fingerprinting. The fingerprint patterns revealed a very low degree of polymorphism in our main study population. We show that this lack of hypervariability is caused by a low effective population size, rather than by an unusual low mutation rate of the fingerprint loci studied. However, the current number of breeding pairs was found to be about an order of magnitude larger than the one that would be expected to lead to such a low degree of heterozygosity. We conclude that there must have been bottlenecks in the history of the Berchtesgaden marmot population that have severely affected its genetic heterozygosity.

Animals↗
PubMed2003

Evaluation of three combinations of anesthetics for use in free-ranging alpine marmots (Marmota marmota).

From April 1998 to September 2000, 241 free-ranging alpine marmots (Marmota marmota) were anesthetized in the course of a field project using either xylazine plus ketamine (XK), medetomidine plus ketamine (MK), or xylazine plus a 1:1 mixture of zolazepam and tiletamine (XZT). For each of the combinations, the respective doses for short term and long-term surgery were established and seasonal variations in the amount of drugs needed were assessed. No fatalities occurred, and doses for efficient and safe anesthesia in spring were as follows (XK, MK, and XZT, respectively, in mg/kg body mass): short term surgery 3 + 40, 0.25 + 35, and 3 + 15; long term surgery 20 + 80, 0.5 + 70, and 10 + 20. In late summer/autumn, higher doses (20 + 60, 0.2 + 60, and 10 + 15 for short term surgery) had to be administered, probably due to increase of marmots' body fat content. Heart rate, respiratory rate, rectal temperature, palpebral reflex, muscle relaxation, and analgesia were monitored to evaluate the animals' responses to each of the drug combinations. Hypothermia was induced by all combinations and heart rate significantly decreased during anesthesia, especially in marmots receiving MK. Respiratory rate was highly variable and no significant differences between the drugs were found. Muscle relaxation was rather poor in marmots anesthetized with XK. The XZT combination tended to have a longer induction period but was found to subsequently depress the palpebral reflex and induce muscle relaxation and analgesia very efficiently. We conclude that, regardless of the anesthetics used, doses should always be adjusted to the planned manipulations, the marmots' nutritional state, and to the time of year. Furthermore, close monitoring of physiologic parameters, especially body temperature, should be guaranteed. On the basis of physiologic and behavioral responses, XZT is the most effective drug combination for anesthetizing alpine marmots, especially for long term, potentially painful procedures.

Anesthesia↗
PubMed2000

Identification of odorant receptors from the Alpine marmot (Marmota marmota).

Alpine Marmots (Marmota marmota) are a good model to study intraspecific chemical communication among mammals. This species has been subjected to several behavioural and biochemical studies regarding both their scent-marking behaviour by cheek-rubbing, and the chemical composition of their glandular secretions. However, no molecular study has been undertaken until today on proteins from the olfactory epithelium possibly implicated in chemical perception. In this study, we identified, to our knowledge for the first time, some olfatory receptors from this wild rodent. Starting with olfactory epithelium of an Alpine Marmot, and by mean of reverse transcriptase polymerase chain reaction technique (RT-PCR), we isolated fourteen partial sequences that exhibited a high degree of homology (45-92%) with olfactory receptors from other vertebrates. Conserved identities and structural features clearly defined these Alpine Marmot sequences as members of the seven transmembrane domain olfactory receptors. All sequences were observed as belonging to known olfactory receptor families and were classified into ten subfamilies of the tetrapods OR class. Finally, Northern blot analysis revealed specific expression of these sequences in the Alpine Marmot olfactory epithelium tissue.

Amino Acid Sequence↗
PubMed1988

The ultrastructure of the thyroid parafollicular cells of the marmot (Marmota marmota). Immunocytochemical localization of calcitonin and somatostatin.

We studied the topographical and ultrastructural characteristics of the parafollicular cells in the Marmota marmota and their seasonal changes. The parafollicular cells, together with the follicular cells, form the follicular epithelium occupying a peculiar basal position. Furthermore these cells are characterized by a clear cytoplasmic matrix and well developed cytoplasmic organelles. The latter synthesize and condense the secretory product which ultrastructurally is organized in secretory granule-vesicles with a scarcely electron-dense cottony content. Histochemically the secretion consists in a proteic complex (rich in alpha-amino acids and sulphonate proteins) with a minor glucidic component. The above metabolic activity closely relates with the seasonal metabolic changes and namely with calcium metabolism. The immunocytochemical reactions revealed the presence of calcitonin and, to a lesser extent, somatostatin. The morphological findings were compared with those observed in other hibernating mammalians and related to the calcium homeostasis.

Animals↗
PubMed2003

Hormonal and behavioural changes during the mating season and pregnancy in Alpine marmots (Marmota marmota).

Under natural and artificial conditions, Alpine marmots (Marmota marmota) are true hibernators with a single breeding season starting immediately upon emergence from hibernation. Over three mating and breeding seasons, hormonal and mating patterns of colony-housed reproductive female marmots were investigated after exit from hibernation. Blood samples were taken for progesterone, oestrogen and relaxin assays with parallel ultrasound investigations. Copulations were observed from the first day after exit from hibernation until the end of pregnancy and reached a maximum number on day 37 before parturition. Mating behaviour was observed between the dominant animals as well as between dominant and subdominant group members. In the first week after exit from hibernation, plasma progesterone was detected in half of the animals. During the third week, progesterone concentrations were significantly higher in pregnant than in non-pregnant animals or animals that had aborted. Immediately after emerging from hibernation, all successfully mated females showed higher serum relaxin values than non-successfully mated animals and this increase in relaxin concentration lasted until the end of pregnancy. The total concentration of oestrogen did not differ between pregnant and non-pregnant animals. The results of this study indicate that progesterone and relaxin might be useful indicators of early pregnancy in Alpine marmots.

Animals↗
PubMed1988

Social thermoregulation during hibernation in alpine marmots (Marmota marmota).

Body temperature (Tb) of socially hibernating alpine marmots, a pair and two family groups, was monitored continuously from October to March with implanted temperature-sensitive radiotransmitters. At the same time, the animals' behaviour was observed. The recurrent entrances into and arousals from hibernation were highly synchronised within groups. Group members always lay huddled together when euthermic and also when torpid with a few exceptions at higher ambient temperatures (Ta). Body contact with euthermic nestmates warmed torpid marmots passively. The Tb of animals reentering hibernation did not fall to values close to Ta as long as euthermic group members were present. Although animals presumably save energy through social thermoregulation, especially when euthermic, these benefits are not necessarily mutual among group members. Differences in thermoregulatory behaviour of individuals described in this study could be responsible for differential weight losses during winter as found in the natural habitat (Arnold 1986).

Animals↗
PubMed2000

Regulation of body temperature and energy requirements of hibernating alpine marmots (Marmota marmota).

Body temperature and metabolic rate were recorded continuously in two groups of marmots either exposed to seasonally decreasing ambient temperature (15 to 0 degrees C) over the entire hibernation season or to short-duration temperature changes during midwinter. Hibernation bouts were characterized by an initial 95% reduction of metabolic rate facilitating the drop in body temperature and by rhythmic fluctuations during continued hibernation. During midwinter, we observed a constant minimal metabolic rate of 13.6 ml O(2) x kg(-1) x h(-1) between 5 and 15 degrees C ambient temperature, although body temperature increased from 7.8 to 17.6 degrees C, and a proportional increase of metabolic rate below 5 degrees C ambient temperature. This apparent lack of a Q(10) effect shows that energy expenditure is actively downregulated and controlled at a minimum level despite changes in body temperature. However, thermal conductance stayed minimal (7.65 +/- 1.95 ml O(2) x kg(-1) x h(-1) x degrees C(-1)) at all temperatures, thus slowing down cooling velocity when entering hibernation. Basal metabolic rate of summer-active marmots was double that of winter-fasting marmots (370 vs. 190 ml O(2) x kg(-1) x h(-1)). In summary, we provide strong evidence that hibernation is not only a voluntary but a well-regulated strategy to counter food shortage and increased energy demands during winter.

Animals↗