| [the first finding of a spontaneous gastric cryptosporidiosis infection in hamsters (phodopus roborovskii satunin, 1903)]. | the desert hamster (phodopus roborovskii satunin, 1903) represents a new host of cryptosporidium muris tyzzer (1907), 1910. this very first finding was made in the laboratories of the national veterinary institute, prague, czech republic. in september 1994 three 11-month and one 3-month desert hamsters were sent for laboratory examination. parasitological examination post mortem of a 3-month desert hamster revealed "large" cryptosporidium oocysts in excrements as well as in the contents of intes ... | 1995 | 8585141 |
| [cryptosporidia and other endoparasites in heifers imported into the czech republic]. | totally 887 heifers of holstein-friesian breed mostly in late pregnancy imported to the czech republic from france (597), germany (89), denmark (181) and holland (20) were examined coprologically from september 1993 to march 1995 in the parasitological laboratory of the national veterinary institute (nvi). prague. feces were sampled individually, rectally, always on days 1-3 following importation from heifers housed in particular quarantine sheds. in compliance with presently valid veterinary re ... | 1995 | 8659084 |
| [taxonomy of ticks of the genus microtimyobia (acariformes: myobiidae: radfordia) and their distribution on voles (rodentia: cricetidae: arvicolinae)]. | a phylogenetic system of the subgenus microtimyobia (myobiidae: radfordia) elaborated for the first time by means of the software hennig-86 is proposed. the subgenus microtimyobia including three species groups, lemnina, hylandi and zibethicalis, was divided for a cladistic analysis into 6 operation units based mainly on a male genital shield structure. the analysis shows, that the zibethicalis group is a polyphyletic, while the hylandi and lemnina groups are monophyletic. host-parasite associat ... | 1998 | 9813883 |
| helminths collected from imported pet murids, with special reference to concomitant infection of the golden hamsters with three pinworm species of the genus syphacia (nematoda: oxyuridae). | a total of 210 individuals of 13 species belonging to 4 subfamilies of muridae imported into japan as pets were examined; 5 species of syphacia (nematoda: oxyuridae), aspiculuris tetraptera (nematoda: heteroxynematidae), and rodentolepis nana (cestoidea: hymenolepididae) were collected. concurrent infection with 3 pinworm species, syphacia mesocriceti, syphacia stroma, and syphacia peromysci, was recorded for the first time in the golden hamster, mesocricetus auratus. syphacia mesocriceti was al ... | 2008 | 18605784 |
| interspecific contact affects phase response and activity in desert hamsters. | circadian rhythms enhance survival and reproductive fitness of animals by promoting optimal timing of behavior and physiology with reference to geophysical changes in environment. although light is considered the dominant stimulus for entraining circadian rhythms, social stimuli can also act as zeitgebers. the aim of this study was to analyze how desert hamsters (phodopus roborovskii) coordinate their behavior in time with that of animals of another competing species (mongolian gerbils, meriones ... | 2009 | 19524601 |
| roborovskin, a lipocalin in the urine of the roborovski hamster, phodopus roborovskii. | many rodents are now known to exhibit an obligate proteinuria that delivers urine-mediated chemosignals. in this paper, we explore the urinary proteins of the roborovski hamster (phodopus roborovskii). sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of urine from individual male and female roborovski hamsters revealed 2 proteins, with approximate masses of 6 and 17 kda, the expression pattern of which showed little variation between individuals or between sexes. peptide mass f ... | 2010 | 20576820 |
| line-1 distribution in six rodent genomes follow a species-specific pattern. | l1 distribution in mammal's genomes is yet a huge riddle. however, these repetitive sequences were already found in all chromosomic regions, and in general, they seem to be nonrandomly distributed in the genome. it also seems that after insertion and when they are not deleterious, they are always involved in dynamic processes occurring on that particular chromosomic region. furthermore, it seems that large-scale genome rearrangements and l1 activity and accumulation are somehow interconnected. i ... | 2016 | 27019429 |
| evidence for species-specific clock gene expression patterns in hamster peripheral tissues. | rhythmic oscillations that repeat every 24h can be found in numerous behavioral and physiological functions. beside the endogenous master clock in the suprachiasmatic nucleus (scn), peripheral oscillators exist that can disengage from the master clock rhythm by different mechanisms. the fact that core clock genes in peripheral tissues do not always have the same characteristics as in the scn suggests that their function may vary in different organs. additionally, suggestions about species-specif ... | 2014 | 25016070 |
| [decorative forms of hamsters phodopus (mammalia, cricetinae): an analysis of genetic lines distribution and peculiarities of hair changes]. | three species of dwarf hamsters (genus phodopus, family cricetidae) inhabit some regions of russia, kazakhstan, mongolia, and china, each having quite extensive range. in recent decades, the dwarf hamsters became widely spread all over the world, initially as laboratory animals and later as popular pets. by now, there is lot of decorative breed lines and colored forms of these animals. comparison of mtdna nucleotide sequences of dwarf hamsters acquired in pet shops of some countries in europe, s ... | 2012 | 22590908 |
| 2-deoxy-d-glucose, not mercaptoacetate, induces a reversible reduction of body temperature in male desert hamsters (phodopus roborovskii). | the initiation of torpor is supposed to be related to the availability of metabolic fuels. studies on metabolic fuel inhibition of glucose by using 2-deoxy-d-glucose (2dg) or fatty acid by mercaptoacetate (ma) in heterothermic mammals produced mixed outcomes. to examine the roles of availability of glucose and fatty acid in the initiation of torpor in desert hamsters (phodopus roborovskii), we intraperitoneally administrated 2dg and ma to summer-acclimated male hamsters while body temperature (t ... | 2018 | 29301689 |
| disparities in activity levels and learning ability between djungarian hamster (phodopus sungorus) and roborovskii hamster (phodopus roborovskii). | the djungarian hamster and the roborovskii hamster belong to the same genus of phodopus. however, the djungarian hamster is tame and shows sedative behavior, while roborovskii hamster is not tame and shows high levels of locomotor activity. hyperactivity occurs in animals with tameless behavior. tameness or tamelessness behavior is very important because tameness helps for breeding and controlling as well as it enables a strong human-animal bond. in the present study, we examined the relationshi ... | 2017 | 27435047 |
| fasting-induced daily torpor in desert hamsters (phodopus roborovskii). | daily torpor is frequently expressed in small rodents when facing energetically unfavorable ambient conditions. desert hamsters (phodopus roborovskii, ~20g) appear to be an exception as they have been described as homeothermic. however, we hypothesized that they can use torpor because we observed reversible decreases of body temperature (tb) in fasted hamsters. to test this hypothesis we (i) randomly exposed fasted summer-acclimated hamsters to ambient temperatures (tas) ranging from 5 to 30°c o ... | 2016 | 27215346 |
| continental refugium in the mongolian plateau during quaternary glacial oscillations: phylogeography and niche modelling of the endemic desert hamster, phodopus roborovskii. | the mongolian plateau (mp), which is situated in the interior of asia and possesses a typical continental climate, experienced harsh climatic conditions during the quaternary glacial fluctuations. although these events likely had huge impacts on the local animal populations, the current effects have hardly been explored. to investigate whether the mp supported a refugium along an oceanic-continental gradient (rocg), and whether this refugium was glacial or interglacial, we investigated the demog ... | 2016 | 26839955 |
| the puzzling character of repetitive dna in phodopus genomes (cricetidae, rodentia). | three novel repetitive dna sequences are described, presenting a similar heterochromatic chromosomal location in two hamster species: phodopus roborovskii and phodopus sungorus (cricetidae, rodentia). namely, two species-specific repetitive sequences (prosat from p. roborovskii and psuchr1sat from p. sungorus) surrounding a third one (psatdna), that is shared by both hamster genomes. fiber-fish analyses revealed that prosat intermingles with psatdna in p. roborovskii and psuchr1sat intermingles ... | 2015 | 26281779 |
| effects of short photoperiod on energy intake, thermogenesis, and reproduction in desert hamsters (phodopus roborovskii). | desert hamsters (phodopus roborovskii) are the least known species in the genus phodopus with respect to ecology and physiology, and deserve scientific attention, particularly because of their small body size. here, the responses of energy metabolism and reproductive function to short photoperiods in desert hamsters were investigated. male and female desert hamsters were acclimated to either long day (ld) (l:d 16:8 h) or short day (sd) photoperiods (l:d 8:16 h) for three months, and then the fem ... | 2015 | 25311843 |
| atypical fibrosarcoma in the skin of a roborovski hamster (phodopus roborovskii). | a 2.5-year-old intact male roborovski hamster (phodopus roborovskii) was presented with a large subcutaneous mass overlying the abdomen, affecting the animal's ambulation and access to different compartments of the cage through narrow tubing. ultrasound examination delineated a well-circumscribed mass in the subcutis of the caudoventral abdominal region. the mass was surgically excised and on cytologic examination showed, in a background of blood, a small population of individually arranged oval ... | 2014 | 24829077 |
| lunar and temperature effects on activity of free-living desert hamsters (phodopus roborovskii, satunin 1903). | time management of truly wild hamsters was investigated in their natural habitat in alashan desert, inner mongolia, china during summer of 2009, 2010, and 2012. duration of activity outside their burrows, duration of foraging walks, and nocturnal inside stays were analyzed with the aim to elucidate impact of moon, ambient, and soil temperature. animal data were determined using radio frequency identification (rfid) technique; for that purpose, individuals were caught in the field and marked with ... | 2014 | 24408344 |
| weather entrainment and multispectral diel activity rhythm of desert hamsters. | the circadian rhythm of animals is an adaptation to predictable variation in environmental conditions. multiple internal oscillators may allow animals to cope with environmental oscillations in different frequencies. heat stress and dramatic differences between night and day temperatures are the main selective pressures of the diel activity of desert mammals, particularly small-sized rodents. we tested the hypotheses that the diel activities of desert hamsters (phodopus roborovskii) would be ent ... | 2013 | 23810901 |
| oestrus cycle of the desert hamster (phodopus roborovskii, satunin, 1903). | the desert hamster, phodopus roborovskii, is one of the lesser-known laboratory animal models and therefore knowledge of its reproductive system and physiology is limited. this study investigated the time course of vaginal and behavioural oestrus cycles by means of vaginal smear cytology, serum luteinizing hormone (lh) levels, wheel-running activity patterns, and pairing tests. the oestrus cycle lasts between four and six days and follows a pattern rather similar to that described for other rode ... | 2013 | 23760567 |
| physical dormancy in seeds: a game of hide and seek? | historically, 'physical dormancy', or 'hard seededness', where seeds are prevented from germinating by a water-impermeable seed coat, is viewed as a dormancy mechanism. however, upon water uptake, resumption of metabolism leads to the unavoidable release of volatile by-products, olfactory cues that are perceived by seed predators. here, we examine the hypothesis that hard seeds are an anti-predator trait that evolved in response to powerful selection by small mammal seed predators. seeds of two ... | 2013 | 23421728 |
| the involvement of repetitive sequences in the remodelling of karyotypes: the phodopus genomes (rodentia, cricetidae). | in this work we characterize the phodopus roborovskii and phodopus sungorus karyotypes, describing the constitutive heterochromatin and the telomeric repeats distribution in these chromosomes. in the two species, (peri)centromeric, interstitial and (sub)telomeric c-bands were revealed, presenting a very high colocalization with evolutionary breakpoint regions identified in these karyotypes. also both species present telomeric sequences located interstitially (its), as short its blocks or as larg ... | 2013 | 23280178 |
| [seasonal peculiarities of female hormonal response of females to conspecific chemical signals of the male in two species of the genus phodopus]. | changes in diestrous female blood plasma progesterone, estradiol, and cortisol in response to odors of urine and midventral gland secretion (mvgs) of conspecific males during different seasons have been studied in the desert hamster (phodopus roborowskii and djungarian hamster (phodopus sungorus). in desert hamster females, a statistically significant (p < or = 0.05) increase in the plasma hormonal level was observed: for progesterone in response to conspecific male mgvs in all seasons except wi ... | 2016 | 22834315 |
| [analysis of genetic diversity of the roborovski hamster (phodopus roborovskii) in the northern part of its habitat]. | an analysis of sequences of the cytochrome b gene and control region of mitochondrial dna of 30 roborovski hamsters (phodopus roborovskii; rodentia: cricetinae) captured at ten geographical points from zaisanskaya depression (kazakhstan) in the northwest to the shilin-gol area (china) in the southeast was conducted. the absence of a connection between the similarity of the discovered haplotypes and their geographical distribution allows us to assume that the modern genetic diversity of the speci ... | 2016 | 21442911 |
| chronic l-tyrosine alters the locomotor activity and brain monoamine levels in roborovskii hamsters. | the roborovskii hamster (phodopus roborovskii) has high locomotor activity (hyperactivity) and low dopamine levels in the brain compared with the congeneric djungarian hamster (phodopus sungorus). to clarify the efficacy of dietary l-tyrosine in ameliorating signs of hyperactivity, we investigated the effects of chronic administration of l-tyrosine, the primary precursor of dopamine, on locomotor activity and brain monoamine levels in roborovskii hamsters. chronic supplementation of l-tyrosine h ... | 2011 | 21056630 |
| thermal physiology and energetics in male desert hamsters (phodopus roborovskii) during cold acclimation. | the adjustments in thermal physiology and energetics were investigated in male desert hamsters (phodopus roborovskii) which were acclimated to 5°c for 4 weeks. mean core body temperature in cold acclimated animals decreased by 0.21°c compared with controls. further analysis revealed that the decrease mainly occurred in the scotophase, while in the photophase core body temperature remained constant during the whole cold acclimation. thermogenic capacity, represented by resting metabolic rate and ... | 2011 | 20714728 |
| l-dopa attenuates hyperactivity of roborovskii hamsters. | the roborovskii hamster (phodopus roborovskii) has been shown to have high locomotor activity (hyperactivity) and low dopamine concentrations in the brain. we hypothesized that low brain dopamine concentrations play a role in the pathogenesis of hyperactivity. in this study, therefore, we investigated the effects of l-dopa (l-3,4-dihydroxyphenylalanine), the precursor of dopamine, on the locomotor activity of roborovskii hamster to verify the above hypothesis. an open field test was employed to ... | 2009 | 19404194 |
| [time shift invariant properties of commonly used growth models and their application]. | growth analysis is of significance in estimating the age of organisms, but in reality, the initial time for this estimation adopted by different authors is not always the same. for example, in the growth analysis of mammals, the age could be birth age or conceptional age. such a discrepancy in time, the so-called time shift, may generate different results in parameter-simulating process. in this paper, the time-shift invariant properties of commonly used three-parameter growth models, i.e., spil ... | 2007 | 17650875 |
| [the reaction of adult roborovskii dwarf hamsters (phodopus roborovskii) to the odor signals of individuals of their own and the opposite sex at different seasons of the year]. | studies were carried out on adult males and females of the roborovskii dwarf hamster kept in natural temperature and light regime throughout the year. the reactions of hamsters to odors of urine, excrements, and the secretory substance of the midabdominal gland from conspecific males and females were studied by the method of alternative selection from a pair of presented odor sources during each of the four seasons. the results obtained were compared with reproduction in the tested individuals. ... | 2016 | 9004898 |
| [a comparative study of the osmoregulating system in the hamsters phodopus roborovskii and phodopus sungorus]. | the hamster phodopus roborovskii is adapted to live in desert, phodopus sungorus in less arid regions. hamsters of both species have rather close values of blood serum osmolality and ion concentration, after dehydration the value of urine osmolality is found to be equally high. the microdissection of the kidney did not reveal any difference in the structure and arrangement of nephrons in cortex and medulla. according to the results of immunocytochemical analysis of the hypothalamo-hypophyseal ne ... | 2006 | 7810260 |
| expression of neuroectodermal markers in atypical fibromas in two dwarf hamsters (phodopus spp.). | a 2-year-old male djungarian hamster (phodopus sungorus) and a 1-year-old male roborovski hamster (phodopus roborovskii) were presented with expansile subcutaneous masses. the well-demarcated, firm, grey, multilobulated nodules displayed an homogeneous, white-grey cut surface. histological examination revealed a neoplasm of variable cellularity consisting of spindle-shaped to polygonal 'ganglion cell-like' cells with abundant, amphophilic, vacuolated cytoplasm. immunohistochemically, the tumour ... | 2019 | 31690416 |
| on the winter enhancement of adaptive humoral immunity: hypothesis testing in desert hamsters (phodopus roborovskii: cricetidae, rodentia) kept under long-day and short-day photoperiod. | we tested the winter immunity enhancement hypothesis (wieh) on male desert hamsters (phodopus roborovskii) kept under long-day (ld) and short-day (sd) photoperiods. we assumed that under sd in a laboratory, the adaptive humoral immune responsiveness to the antigenic challenge would be enhanced due to the lack of winter physical stressors and food shortages and/or because of the action of an endogenous winter bolstering mechanism, while under ld the immune responsiveness would be suppressed by th ... | 2020 | 31773894 |
| precocious torpor in an altricial mammal and the functional implications of heterothermy during development. | most mammals and birds are altricial, small and naked at birth/hatching. they attain endothermic thermoregulation at a fraction of their adult size at a vulnerable stage with high heat loss when many could profit from using torpor for energy conservation. nevertheless, detailed data on the interrelations between torpor expression and development of endothermic thermoregulation are currently restricted to <0.1% of extant endotherms. we investigated at what age and body mass (bm) desert hamsters ( ... | 2019 | 31068837 |
| identification of immunohistochemical localization of irisin in the dwarf hamster (phodopus roborovskii) tissues. | irisin is mainly secreted by heart and skeletal muscle cells. it is an exercise-induced protein that converts white adipose tissue to brown. increased irisin expression was lead to weight loss and improved glucose tolerance. we investigated irisin immunoreactivity in various tissues of the dwarf hamsters (phodopus roborovskii). tissues were processed, embedded in paraffin, sectioned at 5 μm and stained immunohistochemically for irisin. in the retina, irisin was found almost all layers, except ou ... | 2018 | 29527793 |
| the roborovski dwarf hamster is a highly susceptible model for a rapid and fatal course of sars-cov-2 infection. | the coronavirus disease 2019 (covid-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (sars-cov-2) has precipitated an unprecedented and yet-unresolved health crisis worldwide. different mammals are susceptible to sars-cov-2; however, few species examined so far develop robust clinical disease that mirrors severe human cases or allows testing of vaccines and drugs under conditions of severe disease. here, we compare the susceptibilities of three dwarf hamster species (phodop ... | 2020 | 33271063 |