round table on morbilliviruses in marine mammals.since 1988 morbilliviruses have been increasingly recognized and held responsible for mass mortality amongst harbour seals (phoca vitulina) and other seal species. virus isolations and characterization proved that morbilliviruses from seals in northwest europe were genetically distinct from other known members of this group including canine distemper virus (cdv), rinderpest virus, peste des petits ruminants virus and measles virus. an epidemic in baikal seals in 1987 was apparently caused by a m ...19921481361
[the oxygen diffusion coefficient in isolated skeletal muscle fibers].the oxygen diffusion coefficients in isolated skeletal muscle fibres of baikal seal and grayling, white rat, chicken were calculated on the basis of experimentally determined curve of dependence of the o2 consumption on po2 and the radius of the fibres. in all the cases, the diffusion coefficient was smaller in the fibres than in water. the oxygen diffusion coefficient was increased during embryogenesis and postnatal period in chicken. the influence of different parameters of the oxygen transpor ...19911668155
[an experimental infection of the seal phoca sibirica with the morbilli virus].a baikal seal (phoca sibirica) was experimentally infected with baikal seal morbillivirus (bsmv) isolated from baikal seals during an epizootic in 1987-1988. the seal was infected with bsmv with an infectious titer of 10(7.0) tcd50/ml, and daily observations of the animal clinical condition were made. the virus-specific antibodies in the seal serum were determined by elisa and virus neutralization test. the clinical picture showed a mild infection. the elisa-active antibodies were detected 10 da ...19911785189
[the isolation of the morbilli virus from the baikal seal phoca sibirica and its preliminary characterization].a morbillivirus was isolated from the organs of a seal (phoca sibirica) which had died during 1987-1988 epizootic in baikal. this baikal seal morbillivirus (bsm) was adapted to vero cell cultures in which it induced a cytopathic effect developing to complete destruction of the monolayer. typing of bsm was done by indirect immunofluorescence test and enzyme immunoassay using antibodies to distemper and measles viruses. a method for virus concentration and purification was developed. according to ...19911858357
[antibodies to morbilli virus of the baikal seal in its natural host].morbillivirus of baikal seal (bsm) was isolated from organs of a dead animal during 1987-1988 epizootic of baikal seal (phoca sibirica). a method of cellular enzyme immunoassay for testing for virus-specific antibodies was developed using bsm. the method was used for antibody detection in sera of 115 apparently normal seals collected in the spring of 1989. antibody to bsm were found in sera from 75 animals. examinations of seropositive animals of different age and sex were carried out. the resul ...19902082556
comparison of two morbilliviruses isolated from seals during outbreaks of distemper in north west europe and siberia.recently morbilliviruses were isolated from harbour seals (phoca vitulina) in north west europe (phocid distemper virus-1: pdv-1) and from baikal seals (phoca sibirica) in siberia (phocid distemper virus-2: pdv-2) during outbreaks of severe disease which resembled distemper in dogs. pdv-1 and pdv-2 were passaged in spf dogs, in which they caused distemper-like disease symptoms, and were subsequently passaged in vero cells in which they caused cytopathic changes. pdv-1, pdv-2, and canine distempe ...19902141248
mass mortality in seals caused by a newly discovered morbillivirus.during a recent disease outbreak among harbour seals (phoca vitulina) in the north and baltic seas, more than 17,000 animals have died. the clinical symptoms and pathological findings were similar to those of distemper in dogs. based on a seroepizootiological study, using a canine distemper virus (cdv) neutralization assay, it was shown that cdv or a closely related morbillivirus (phocid distemper virus-pdv) was the primary cause of the disease. the virus was isolated in cell culture from the or ...19902205971
[distemper in a population of the baikal seal]. 19902256402
baikal seal virus. 19892725642
distemper virus in baikal seals. 19892922047
[neutralizing morbillivirus antibodies in the population of the baikal seal phoca sibirica].the antibodies neutralizing baikal seal morbillivirus (bsmv) were studied in sera from 148 normal baikal seals (phoca sibirica). the virus-neutralizing antibodies were demonstrated in sera of 61.5% of the animals examined. a comparative analysis of antibodies in nt and cell-elisa method is presented. the role of bsmv in morbidity and mortality of seals (phoca sibirica) is discussed.19938073742
fusion protein gene nucleotide sequence similarities, shared antigenic sites and phylogenetic analysis suggest that phocid distemper virus type 2 and canine distemper virus belong to the same virus entity.nucleotide sequencing of the fusion protein (f) gene of phocid distemper virus-2 (pdv-2), recently isolated from baikal seals (phoca sibirica), revealed an open reading frame (nucleotides 84 to 2075) with two potential in-frame atg translation initiation codons. we suggest that the second in-frame atg triplet at positions 264 to 266 initiates the translation, resulting in a protein of 537 amino acid residues with a calculated m(r) of 63,035. the putative f1/f2 cleavage site, located approximatel ...19938376973
prevalence of morbilliviruses among pinniped and cetacean species.since 1987, morbillivirus infections have caused serious disease outbreaks with high mortality among aquatic mammals. baikal seals (phoca sibirica) in siberia were involved in an outbreak caused by a virus closely related to canine distemper virus (cdv) in 1987. harbour seals (phoca vitulina) and grey seals (halichoerus grypus) in north-western europe were struck by a newly recognised morbillivirus of seals (pdv1). a serological survey has indicated that these morbillivirus infections frequently ...19938518442
morbilliviruses and morbillivirus diseases of marine recent years, serious disease outbreaks among seals and dolphins were attributed to infection with established or newly recognized morbilliviruses. the first identification of a morbillivirus as causative agent of mass mortality among marine mammals was in 1988, when the previously unrecognized phocine distemper virus (pdv) caused the death of 20,000 harbor seals (phoca vitulina) in northwestern europe. a similar epizootic among baikal seals (phoca sibirica) in siberia in 1987 was later attri ...19958548190
morbillivirus infections of aquatic mammals: newly identified members of the genus.several disease outbreaks, which have caused the deaths of many thousands of seals and dolphins during the last decade, have now been attributed to infections with newly identified morbilliviruses. outbreaks in the late eighties amongst harbour seals (phoca vitulina) and grey seals (halichoerus grypus) in northwestern europe and amongst baikal seals (phoca sibirica) in siberia were caused by the newly discovered phocine distemper virus and by a strain of canine distemper virus, respectively. alt ...19958588316
canine distemper virus in lake baikal seals (phoca sibirica).the virus epizootic which resulted in significant mortality in siberian seals (phoca sibirica) in lake baikal during 1987/88 was caused by canine distemper virus. sequence analysis of the virus glycoprotein genes revealed that it was most closely related to recent european field isolates of canine distemper virus. this paper presents evidence that the same virus continued to circulate in seals in lake baikal after the initial epizootic. three out of 45 brain tissue samples collected from seals c ...19968735261
morbillivirus infections in aquatic mammals.morbillivirus infections which were not documented in aquatic mammals until 1988, have caused at least five epizootics in these species during the last 10 years. affected populations include european harbour seals (phoca vitulina) and grey seals (halichoerus grypus) in 1998, baikal seals (phoca siberica) in siberia from 1987-1988, striped dolphins (stenella coeruleoalba) in the mediterranean sea from 1990-1992 and bottlenose dolphins (tursiops truncatus) along the eastern coast of the united sta ...19989807724
[molecular-genetic comparison of morbilliviruses which caused epizooty in baikal (phoca siberica) and caspian (phoca caspica) seals].the nucleotide sequences were determined for a phosphoprotein gene fragment of canine distemper virus (cdv) by using the rt-pcr method with the subsequent sequencing of amplicons from total rna isolated from 2 samples of caspian seals, 15 samples of baikal seals and from samples of dog's and sea-lion's brains. the above materials were phylogenetically analyzed. the heterogeneity of the virus circulating in the baikal-seal population was demonstrated. morbillivirus, that caused epizooty in caspia ...200314664160
toxicokinetics of pcdd, pcdf, and coplanar pcb congeners in baikal seals, pusa sibirica: age-related accumulation, maternal transfer, and hepatic assess the toxicokinetic behavior and potential toxicity of polychlorinated dibenzo-p-dioxins (pcdds), polychlorinated dibenzofurans (pcdfs), and coplanar polychlorinated biphenyls (pcbs) in baikal seals, congener-specific levels and tissue distribution were evaluated in the liver and blubber, and the effects of biological factors including sex and growth were assessed. total 2,3,7,8-tcdd toxic equivalents (teqs) were in the range of 210-920 pgteq/g fat wt (180-800 pgteq/g wet wt) in the blub ...200415296299
antibodies to human-related h3 influenza a virus in baikal seals (phoca sibirica) and ringed seals (phoca hispida) in russia.antibodies to influenza a virus were detected using enzyme-linked immunosorbent assay (elisa) in the sera from two of seven baikal seals (phoca sibrica) and from five of six ringed seals (phoca hispida) in russia. in a hemagglutination-inhibition test using h1-h15 reference influenza a viruses, elisa-positive sera from one baikal seal and four ringed seals reacted to a/aichi/2/68 (h3n2) and a/bangkok/1/79 (h3n2) strains. one ringed seal serum sample reacted to a/seal/massachusetts/1/80 (h7n7). t ...200415557750
contamination and effects of perfluorochemicals in baikal seal (pusa sibirica). 2. molecular characterization, expression level, and transcriptional activation of peroxisome proliferator-activated receptor investigate the biological effects of perfluorochemicals (pfcs) and to identify biomarkers of exposure to pfcs, this study focused on the effects mediated by peroxisome proliferator-activated receptor alpha (pparalpha) in baikal seals (pusa sibirica). we cloned a full-length cdna, encoding pparalpha from the liver of baikal seal, which has a deduced open reading frame of 468-amino acid residues with a predicted molecular mass of 52.2 kda. comparison of the amino-acid sequence of baikal seal p ...200818504957
radionuclide ((137)cs and (40)k) concentrations in the muscle of baikal seal (pusa sibirica) from lake baikal. 200919117578
identification of major dioxin-like compounds and androgen receptor antagonist in acid-treated tissue extracts of high trophic-level animals.we evaluated the applicability of combining in vitro bioassays with instrument analyses to identify potential endocrine disrupting pollutants in sulfuric acid-treated extracts of liver and/or blubber of high trophic-level animals. dioxin-like and androgen receptor (ar) antagonistic activities were observed in baikal seals, common cormorants, raccoon dogs, and finless porpoises by using a panel of rat and human cell-based chemical-activated luciferase gene expression (calux) reporter gene bioassa ...201122003927
a 9,000 year history of seal hunting on lake baikal, siberia: the zooarchaeology of sagan-zaba ii.sagan-zaba ii, a habitation site on the shore of siberia's lake baikal, contains a record of seal hunting that spans much of the holocene, making it one of the longest histories of seal use in north asia. zooarchaeological analyses of the 16,000 baikal seal remains from this well-dated site clearly show that sealing began here at least 9000 calendar years ago. the use of these animals at sagan-zaba appears to have peaked in the middle holocene, when foragers used the site as a spring hunting and ...201526009890
[structure of the endotheliocytes of cerebral vessels of aquatic mammals].by means of scanning microscopy the relief of luminal surface of endotheliocytes, lining microvessels of various parts of the brain in the pusa sibirica, phoca vitulina and delphinapterus leucas have been studied. specialized formations of the cellular surface--various processes, projections, toruli have been revealed; their character in various parts of the brain in diving animals is determined by the blood stream conditions and their different sensitivity to oxygen deficiency during diving. th ...19912053874
[an estimation of the time of divergence of the seals phoca vitulina, phoca largha and phoca sibirica from a common ancestral species]. 20069381856
accumulation features and temporal trends of pcdds, pcdfs and pcbs in baikal seals (pusa sibirica).this study investigated the accumulation features and temporal trends of pcdd/fs, dioxin-like pcbs (dl-pcbs) and non-dioxin-like pcbs (ndl-pcbs) in the blubber of baikal seals collected in 1992 and 2005. dl-pcbs (480-3600ng/g) and ndl-pcbs (980-35,000ng/g) were dominant contaminants. concentrations of pcdds and pcbs in males were significantly higher than in females. in males, age-dependent accumulation was observed for pcdds, mono-ortho pcbs and ndl-pcbs. pcdfs and non-ortho pcbs showed no such ...200919110354
cdna cloning of an aryl hydrocarbon receptor from baikal seals (phoca sibirica).species differences in sensitivity to related planar halogenated aromatic hydrocarbons (phah) add significant uncertainty in assessing the ecological risk to aquatic mammals. to investigate mechanisms of phah sensitivity in aquatic mammals, we cloned and sequenced the cdna of baikal seal aryl hydrocarbon receptor (ahr), an intracellular protein that initiates phah-mediated effects. the baikal seal ahr cdna has an open reading frame of 843 amino acid residues with a predicted molecular mass of 94 ...201612408578
[glycogen, glucose, lactate and pyruvate in the organs of 3 species of adult seals (pusa sibirica, p. caspica, phoca vitulina)]. 201310519198
growth in pinnipeds.this review presents summary figures of, and fits growth curves to, data on body lengths (as standard length, sl, whenever possible) of pinnipeds at ages estimated to o.i y. (1) generalized von bertalanffy (vb) growth curves are fitted to most data: lx = l infinity (i - ea(x-x0)b, lx is length at age x, x0 is the origin of the curve (here chosen a priori as time of initiation of embryonic growth), l infinity is asymptotic length, a (which is negative) determines rate of approach to the asymptote ...19938457634
temporal trends of persistent organochlorine contamination in russia: a case study of baikal and caspian examine temporal trends of organochlorine (oc) contamination in lake baikal and the caspian sea, concentrations of persistent ocs, such as ddt and its metabolites (ddts), polychlorinated biphenyls (pcbs), hexachlorocyclohexane (hchs), chlordane compounds (chls), tris(4-chlorophenyl)methane (tcpme), and tris(4-chlorophenyl)methanol (tcpmoh), in the blubber of female seals were determined. collections were made in 1992, 1993, 1995 and 1998. ddt concentrations in baikal and caspian seals showed ...200312712284
comparison of trace element accumulation in baikal seals (pusa sibirica), caspian seals (pusa caspica) and northern fur seals (callorhinus ursinus).concentrations of 18 trace elements (v, cr, mn, co, cu, zn, se, rb, sr, zr, mo, ag, cd, sb, cs, hg, tl and pb) were determined in liver, kidney, muscle and hair of baikal seals, caspian seals and northern fur seals. all the three species showed the highest concentrations of hg, v, mn, se and ag in liver, cd, co and tl in kidney, and cs in muscle among the soft tissues examined. the highest burdens of zn, rb and cs were observed in muscle, mo and ag in liver, and sb and pb in hair in all the thre ...200414553998
pinniped phylogeny and a new hypothesis for their origin and dispersal.the relationships and the zoogeography of the three extant pinniped families, otariidae (sea lions and fur seals), odobenidae (one extant species, the walrus), and phocidae (true seals), have been contentious. here, we address these topics in a molecular study that includes all extant species of true seals and sea lions, four fur seals and the walrus. contrary to prevailing morphological views the analyses conclusively showed monophyletic pinnipedia with a basal split between otarioidea (otariid ...200616815048
enzymatic characterization of in vitro-expressed baikal seal cytochrome p450 (cyp) 1a1, 1a2, and 1b1: implication of low metabolic potential of cyp1a2 uniquely evolved in aquatic mammals.this study aimed to elucidate the catalytic function of cytochrome p450 (cyp) 1 enzymes in aquatic mammals. alkoxyresorufin o-dealkylation (arod) activities including methoxy- (mrod), ethoxy- (erod), pentoxy- (prod), and benzyloxyresorufin o-dealkylation (brod), and 2- and 4-hydroxylation activities of 17β-estradiol (e2) were measured by using yeast-expressed baikal seal (pusa sibirica) cyp1a1, 1a2, and 1b1 proteins. heterologous protein expression of the baikal seal cyp1s (bscyp1s) in yeast mic ...201525814058
localization of the high-resolution area in the ganglion cell layer of the baikal seal pusa sibirica gm.1788.the morphological and functional density of the retinal ganglion cells of the baikal lake endemic seal pusa sibirica was studied using cresyl-violet-stained whole-mounts. an area of the highest concentration of ganglion cells has been identified by drawing up a density map. this was an ellipsoid spot in the upper temporal part of the retina 6-7 mm from the visual nerve output. the maximum cell density in this area was 3800 cells/mm(2). the retinal resolution estimated from the maximum density of ...201627193874
in vitro and in silico analyses for predicting hepatic cytochrome p450-dependent metabolic potencies of polychlorinated biphenyls in the baikal seal.the aim of this study was to understand the cytochrome p450 (cyp)-dependent metabolic pathway and potency of polychlorinated biphenyls (pcbs) in the baikal seal (pusa sibirica). in vitro metabolism of 62 pcb congener mixtures was investigated by using liver microsomes of this species. a decreased ratio of over 20% was observed for cb3, cb4, cb8, cb15, cb19, cb22, cb37, cb54, cb77, and cb105, suggesting the preferential metabolism of low-chlorinated pcbs by cyps. the highly activated metabolic pa ...201526579933
canine distemper virus: an emerging disease in wild endangered amur tigers (panthera tigris altaica).fewer than 500 amur tigers (panthera tigris altaica) remain in the wild. due to low numbers and their solitary and reclusive nature, tiger sightings across their range in the russian far east and china are rare; sightings of sick tigers are rarer still. serious neurologic disease observed in several wild tigers since 2001 suggested disease emergence in this endangered species. to investigate this possibility, histology, immunohistochemistry (ihc), in situ hybridization (ish), and reverse transcr ...201323943758
the ancestral carnivore karyotype as substantiated by comparative chromosome painting of three pinnipeds, the walrus, the steller sea lion and the baikal seal (pinnipedia, carnivora).karyotype evolution in carnivora is thoroughly studied by classical and molecular cytogenetics and supplemented by reconstructions of ancestral carnivora karyotype (ack). however chromosome painting information from two pinniped families (odobenidae and otariidae) is noticeably missing. we report on the construction of the comparative chromosome map for species from each of the three pinniped families: the walrus (odobenus rosmarus, odobenidae-monotypic family), near threatened steller sea lion ...201626821159
[structure of the neocortex of the baikal ringed seal (pusa sibirica gm.)].the sulci and gyri of the neocortex, as well as cyto-, synaptoarchitectonics and neuronal composition of the sensomotor (brain area) have been studied in the baikal ringed seal. the structure of the sulci and gyri have been found to be similar to that in carnivores. the following specific features have been revealed in the brain of this endemic species: a thick layer i, presence of giant pyramidal cells in the layer iii, large mitochondria in the presynaptic parts and dendrites. the results obta ...20061698050
evaluation of relative potencies for in vitro transactivation of the baikal seal aryl hydrocarbon receptor by dioxin-like evaluate the sensitivity and responses to dioxins and related compounds (drcs) via aryl hydrocarbon receptor (ahr) in baikal seals (pusa sibirica), we constructed an in vitro reporter gene assay system. baikal seal ahr (bs ahr) expression plasmid and a reporter plasmid containing cyp1a1 promoter were transfected in cos-7 cells. the cells were treated with six representative congeners, and dose-dependent responses were obtained for all the congeners. ec(50) values of 2,3,7,8-tcdd, 1,2,3,7,8-pe ...201121204517
canine distemper virus diversity in lake baikal seal (phoca sibirica) population.morbillivirus epizootics in marine mammals have been found in a variety of marine mammal species throughout the world over the past 20 years. the virus epizootic which resulted in significant mortality of siberian seals (phoca sibirica) in lake baikal during 1987-1988 was caused by the canine distemper virus (cdv). in our previous papers we provided evidence that the cdv similar to strain, identified in 1988, continued to circulate in lake baikal seals after 1988. the aim of this study was an up ...201020083361
transactivation potencies of baikal seal constitutive active/androstane receptor by persistent organic pollutants and brominated flame characterize ligand-dependent transcriptional activation of constitutive active/androstane receptor (car) in aquatic mammals, transactivation potentials of the baikal seal (pusa sibirica) car (bscar) by environmental pollutants, including persistent organic pollutants (pops) and brominated flame retardants (bfrs), were investigated using an in vitro reporter gene assay, and compared with those of the mouse car (mcar). measurement of luciferase reporter gene activities demonstrated that the se ...200919746742
molecular characterization of cytochrome p450 1a1, 1a2, and 1b1, and effects of polychlorinated dibenzo-p-dioxin, dibenzofuran, and biphenyl congeners on their hepatic expression in baikal seal (pusa sibirica).this study attempts to relate the 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalent (teq) level with certain responses including the catalytic activities and expression of hepatic cytochrome p450 (cyp) 1a and cyp1b in wild population of baikal seal (pusa sibirica). we isolated full-length cyp1a1, 1a2, and 1b1 cdnas, which encode proteins of 516, 512, and 543 amino acids, respectively. immunochemical analysis demonstrated that a cross-reactive protein with polyclonal antibody against rat cyp1a ...200717383972
genetic diversity of hungarian canine distemper virus achieve proper diagnosis of dogs based on acute clinical symptoms and poorly preserved field samples taken from animals that died due to canine distemper (cd), a new differential diagnostic test has been developed based on polymerase chain reaction (pcr). in this study, more than 150 samples collected from dogs showing respiratory, gastrointestinal and neurological signs suggesting canine distemper virus (cdv) infection were examined. the samples consisted of urine, blood and nasal swabs coll ...200717350769
bioaccumulation of mercury in the pelagic food chain of the lake baikal.mercury (hg) concentrations were analyzed in the livers of baikal seals and in plankton, zoobenthos and fish which constitute food items for the seals. concentrations of hg in the liver of baikal seals were up to two orders of magnitude lower than those in seals inhabiting other lakes. the low levels of hg are due to the low levels of the hg in the fish from the family comephoride, which reflect the very low concentrations of hg in baikal water. the development stage (pups and adults) and the se ...201020117820
constitutive androstane receptor (car) as a potential sensing biomarker of persistent organic pollutants (pops) in aquatic mammal: molecular characterization, expression level, and ligand profiling in baikal seal (pusa sibirica).to characterize the function of constitutive active/androstane receptor (car) in aquatic mammals, car complementary dna (cdna) was cloned from the liver of baikal seal (pusa sibirica) from lake baikal, russia, and the messenger rna (mrna) expression levels in various tissues/organs of the wild population and the car ligand profiles were investigated. the seal car cdna had an open reading frame of 1047 bp encoding 348 amino acids that revealed 74-84% amino acid identities with cars from rodents a ...200616929008
[structural organization of mesenteric lymph nodes in postnatal development of the baikal seal, pusa sibirica gmel].structural organization of mesenteric lymph nodes in the baikal seal has been studied with regard to its age-dependent changes. it has been shown that the relative area of connective tissue structures (the capsule and trabeculae) increases during postnatal development, while the areas of the cortex and medulla decrease. the proportions of secondary lymph nodes and paracortical zone in the cortex become smaller, with the corticomedullary index tending to decrease with age. these phenomena indicat ...201618771029
contamination and effects of perfluorochemicals in baikal seal (pusa sibirica). 1. residue level, tissue distribution, and temporal trend.concentrations of perfluorochemicals (pfcs) including perfluoroalkylsulfonates (pfsas) and perfluoroalkylcarboxylates (pfcas) were determined in liver and serum of baikal seals (pusa sibirica) collected from lake baikal, russia in 2005. among the 10 pfc compounds measured, perfluorononanoic acid (pfna, 3.3-72 ng/g wet wt) concentrations were the highest in liver, followed by perfluorooctanesulfonate (pfos, 2.6-38 ng/g). the accumulation profile of long-chain (c7-c12) pfcas in particular, the pre ...200818504956
identification of constitutive androstane receptor cdna in northern fur seal (callorhinus ursinus).constitutive androstane receptor (car) plays a key role in the transcriptional regulation of cyp2b, 2c and 3a genes in response to phenobarbital, ortho-chlorine substituted polychlorinated biphenyls (pcbs) and sex steroids in rodents and human. however, studies addressing car are limited to certain laboratory animals and cell lines, and there is little information on the presence of car and its physiological and contaminant-related functions in wildlife. while aquatic mammals including seal spec ...200415178021
body density affects stroke patterns in baikal seals.buoyancy is one of the primary external forces acting on air-breathing divers and it can affect their swimming energetics. because the body composition of marine mammals (i.e. the relative amounts of lower-density lipid and higher-density lean tissue) varies individually and seasonally, their buoyancy also fluctuates widely, and individuals would be expected to adjust their stroke patterns during dives accordingly. to test this prediction, we attached acceleration data loggers to four free-rangi ...200616916962
recent contamination by persistent organochlorines in baikal seal (phoca sibirica) from lake baikal, russia.blubber samples of baikal seals pups (phoca sibirica) collected in 2001 and 2002 were analyzed for persistent organochlorines (ocs) such as pcbs (polychlorinated biphenyls), ddts (dichlorodiphenyltrichloroethane and its metabolites), hchs (hexachlorocyclohexane isomers), chls (chlordane related compounds), tcpme [tris(4-chlorophenyl)methane] and tcpmoh [tris(4-chlorophenyl)methanol]. the distribution pattern of ocs was in the following order: ddts>pcbs>chls>hchs>tcpmoh>tcpme. organochlorine conc ...200415041431
relationships and bioaccumulation of chemical elements in the baikal seal (phoca sibirica).concentrations of al, ba, cd, cu, fe, mn, mo, si, sr, zn, ca, k, mg, na and p in the livers of baikal seal, plankton, zoobenthos, and fish, constituting the food sources for the seals, were determined by icp-ms and icp-aes. the accumulation of elements in the liver of seals, affected by internal and external (environmental) factors, was assessed by multidimensional (anova, fa) and correlation analyses. fa has enabled identification of abiotic and biotic factors responsible for the accumulation o ...200616084000
[oxygen requirement for baikal pusa sibirica and factors, influencing it]. 200611898600
[antigenic characteristics of morbillivirus isolates from baikal seals].four morbillivirus strains were isolated from the baikal seals phoca sibirica. the antigen difference between these strains was studied using elisa with different immune sera and monoclonal antibodies. the assay data indicated three different antigen variants of morbillivirus. the four strains were found to circulate over the baikal seal population during epizootic.200312924101
[lymphoid structure in the mouse cecum wall during immunosuppression and its correction with liposomal agents].the influence of liposomal preparation obtained from the baikal seal fat on lymphoid structures in mouse coecum wall on the background of immunodepressive state induced by asathioprine was studied using microscopic methods and statistic analysis. it was demonstrated that asaphioprine administration caused decline in lymphoid serie cells, outgrowth of adipose tissue, causes destructive changes of lymphoid structures in the coecal wall. after the effect of liposomes on the background on the immune ...200111586648
seroepidemiological survey of distemper virus infection in the caspian sea and in lake baikal.forty caspian seals were surveyed seroepidemiologically between 1993 and 1998 around the times of mass mortality that occurred in 1997 in the caspian sea and seven baikal seals were also surveyed in 1998. virus neutralizing tests and elisa clearly suggested that distemper virus epidemic was caused in caspian seals before the spring of 1997 and that cdv infection continued to occur in lake baikal in recent years.200111470542
[vascular responses in the baikal seal pusa sibirica during diving of different types]. 20069720150
[the total and intraorganic circulating blood volume in pups of the baikal seal pusa sibirica during diving]. 20069703674
[structural reorganization of the cerebral capillary wall in the baikal seal pusa sibirica during diving]. 20069542057
[oxygen deficit after prolonged diving in baikal seal pusa sibirica and metabolic diving depression]. 20069542048
[dioxin and furan levels in baikal seals]. 19979289285
[the structure of the fragments of 3 exons of the myoglobin gene in the baikal seal phoca sibirica].three exon regions of the myoglobin gene of baikal seal phoca sibirica have been amplified and sequenced. the sequences have been found identical to those for the myoglobin gene of the north atlantic seal halichoerus grypus. thus, these seal species have separated not earlier than 2.2 billion years before present.19969092243
trace element accumulation in baikal seal (phoca sibirica) from the lake baikal.trace element concentrations (fe, mn, zn, cu, pb, ni, cd, co and hg) were determined in 60 baikal seals and in fishes collected from lake baikal in 1992. low levels of hg and cd were found in baikal seals in comparison with those of marine mammals and it was due to their low concentrations in dietary fish. these results suggest that pollution by hg and cd was low in lake baikal and these toxic elements were unlikely to be the causative factors for mass mortality of baikal seal in 1987-1988. sign ...199615093503
persistent organochlorine residues and their accumulation kinetics in baikal seal (phoca sibirica) from lake baikal, russia. 199522206538
[the composition of the blood in pups of the baikal seal phoca sibirica during forced diving].a set of parameters, such as po2, pco2, the content of glucose, glycogen, lactate, pyruvate, cholesterol, insulin, triglycerides, camp in the blood from the venous sinus has been investigated in puppies of baikal seals during forced diving and rehabilitation. the dynamics of these parameters is presented.20067571911
[the reaction of the neocortical structures in the seal pusa sibirica to a prolonged stay under water].using light and electron microscopic techniques, structural and functional changes in the neurones and glia of the baikal seal neocortex were revealed during diving. these changes include shifts in tinctorial properties of cells, in the number of dendritic spines, cell ultrastructure (condensation and redistribution of nuclear chromatin, swelling of organoids, etc.). these changes are both non-specific and reversible, indicating high reserve capacities of the brain in this species.20167810262
[the structural organization of the sensorimotor cortex in the baikal seal pusa sibirica]. 20107817661
characterisation of morbilliviruses isolated from lake baikal seals (phoca sibirica).sequence analysis of the haemagglutinin protein (h) gene of the morbillivirus (pdv-2) isolated from a siberian seal (phoca sibirica) during the 1987/1988 epizootic in lake baikal revealed that it was most closely related to two recent isolates of canine distemper virus (cdv) from germany and different from cdv vaccines currently in use in that region. the virus continued to circulate in seals in lake baikal after the 1987/1988 epizootic since sera collected from culled seals in the spring of 199 ...19958588319
[testing the homozygosity of baikal seal using data on genetic variability of proteins].interspecies genetic variability of baikal seal was studied for 22 proteins encoded by 24 loci. genetic variants have been detected in transferrin (tfa = 0.96; tfb = 0.04), postalbumin (paa = 0.130; pab = 0.870) and "slow" carboxylesterase (cre-6a = 0.98; cre-6b = 0.02). low genetic variability is characteristic of species as well as of many other representatives of pinnipedia order.19902344959
[oxygen consumption of the baikal seal during unrestrained swimming in a pool and diving of different duration].in 7 male baikal seals (14-49 kg) spending 60-90% of the time under water, swimming unrestrained in the swimming pool, the average vo2 ranged from 8.6 +/- 7.01 ml (kg min)-1 for a 14-kg seal up to 4.8 +/- 2.22 ml (min kg)-1 (+ sigma) for adult 49-kg seal. a short forced diving (3-5 min) induced no change of the vo2 level because of stored oxygen. more prolonged diving (10-30 min) induced a 2-3-fold reduction of general vo2 and accumulation of a considerable o2-dept. during 3-5 min, 50-80% of thi ...19863758422
[chromosome sets of greenland, caspian and baĭkal seals and some problems of the evolution of true seals]. 19715561225
functional relationship between muscles of mastication and the skull with enlarged orbit in the baikal seal (phoca sibirica).we expected that the enlarged area of zygomatic arch, one of some skull characters adapted for enlarged eye, has an influence on form and function of muscles of mastication in the baikal seal (phoca sibirica). so, in this species, the mm, masseter, temporalis, pterygoidei, digastricus were observed in the macroscopic level. the skull characters related to these muscles were also compared between the baikal seal and a close-related species, the ringed seal (phoca hispida). the mm, masseter and te ...19989673940
arsenic accumulation in the liver tissue of marine mammals.arsenic concentrations were determined in livers of 226 individuals representing 16 different marine mammal species to elucidate its accumulation with age, sex, and feeding habits. arsenic concentrations varied widely among species and individuals, and ranged from < 0.10 to 7.68 micrograms g-1 dry weight. marine mammals feeding on cephalopods and crustaceans contained higher arsenic concentrations than those feeding on fishes. no significant gender difference in arsenic concentration was found f ...200111706803
the muscles of mastication in the caspian seal (phoca caspica).the muscles of mastication and their related skull characters in the caspian seal (phoca caspica) were anatomically examined and compared with those of the baikal (phoca sibirica) and ringed (phoca hispida) seals. a well-developed masseter muscle was observed in the caspian seal, whereas the temporal muscle consisted of thin bundles. the skull of the caspian seal possessed the same thin frontal bone and the dorso-ventrally developed zygomatic arch found in the baikal seal that are required to in ...200212484416
the origin and genetic relationships of the baikal seal, phoca sibirica, by restriction analysis of mitochondrial dna.the origin and genetic relationships of the baikal seal, phoca sibirica, were studied by restriction fragment length polymorphism analysis of mitochondrial dna (mtdna). using 17 different six-base recognition restriction endonucleases, we examined 98 baikal seals, and two other related species, the ringed seal, p. hispida, (n=87), and the caspian seal, p. caspica, (n=94). analysis revealed the existence of 87 mtdna haplotypes in the total of 279 specimens. the haplotypes of each species were div ...200314624043
polychlorinated dibenzo-p-dioxins (pcdds) and dibenzofurans (pcdfs) in baikal seal.polychlorinated dibenzo-p-dioxins (pcdds) and dibenzofurans (pcdfs) were determined in blubber tissue of one 3 month and two adult female seals from lake baikal. high pcdd and pcdf concentrations were found in the baikal seal. the levels are comparable with those reported for ringed seals (phoca hispida) living in the baltic sea, and barrow strait and admiralty inlet in the canadian arctic.19979192468
long-term and ontogenetic patterns of heavy metal contamination in lake baikal seals (pusa sibirica).little is known about the history of heavy metal pollution of russia's lake baikal, one of the world's largest lakes and a home to numerous endemic species, including the baikal seal, pusa sibirica. we investigated the history of heavy metal (v, cu, zn, cd, hg, tl, pb, u) pollution in lake baikal seals over the past 8 decades. c and n stable isotope analysis (sia) and laser-ablation icp-ms of seal teeth were used to examine changes in feeding ecology, heavy metal levels associated with life hist ...201728793769
pcbs and ocps in human milk in eastern siberia, russia: levels, temporal trends and infant exposure assessment.the aim of our study is to investigate the spatial distribution of polychlorinated biphenyls (pcbs), hexachlorobenzene (hcb), dichlorodiphenyltrichloroethane (p,p'-ddt) and its metabolites, α- and γ-isomers of hexachlorocyclohexane (hch) in 155 samples of human milk (hm) from eastern siberia (six towns and seven villages in irkutsk region, one village of the republic of buryatia and one town in zabaikal'sk region, russia), and to examine the dietary and social factors influencing the human expos ...201728329713
retinal ganglion cell topography and retinal resolution in the baikal seal (pusa sibirica).the total number, size, topographic distribution, and cell density of ganglion cells were studied in retinal wholemounts of baikal seals (pusa sibirica). the ganglion cell size varied from 10 to 38 μm. a distinct cell group consisted of large ganglion cells of more than 30 μm in diameter. the topographic distribution of ganglion cells showed a definite area of high cell density similar to the area centralis of terrestrial carnivores. this area was located approximately 6-7 mm dorsotemporally of ...201627529170
drift dives and prolonged surfacing periods in baikal seals: resting strategies in open waters?many pinnipeds frequently rest on land or ice, but some species remain in open waters for weeks or months, raising the question of how they rest. a unique type of dive, called drift dives, has been reported for several pinnipeds with suggested functions of rest, food processing and predator avoidance. prolonged surfacing periods have also been observed in captive seals and are thought to aid food processing. however, information from other species in a different environment would be required to ...201526139663
toxicological assessment of polychlorinated biphenyls and their metabolites in the liver of baikal seal (pusa sibirica).we have previously reported that high accumulation of dioxins and related compounds induced cytochrome p450 (cyp 1s) isozymes in the liver of wild baikal seals, implying the enhanced hydroxylation of polychlorinated biphenyls (pcbs). the present study attempted to elucidate the residue concentrations and patterns of pcbs and hydroxylated pcbs (oh-pcbs) in the livers of baikal seals. the hepatic residue concentrations were used to assess the potential effects of pcbs and oh-pcbs in combination wi ...201425343573
blood levels of polychlorinated biphenyls and their hydroxylated metabolites in baikal seals (pusa sibirica): emphasis on interspecies comparison, gender difference and association with blood thyroid hormone levels.we have previously demonstrated that baikal seals (pusa sibirica) are still being exposed to polychlorinated biphenyls (pcbs), and the population is at risk. in the present study, we measured the residue levels of pcbs and their hydroxylated metabolites (oh-pcbs) in the blood of baikal seals and assessed the impact of oh-pcbs on the thyroid function. blood concentrations of pcbs and oh-pcbs were in the range of 2.8-130 ng g(-1)wet wt. and 0.71-4.6 ng g(-1)wetwt., respectively. concentrations of ...201425113177
burying dogs in ancient cis-baikal, siberia: temporal trends and relationships with human diet and subsistence practices.the first objective of this study is to examine temporal patterns in ancient dog burials in the lake baikal region of eastern siberia. the second objective is to determine if the practice of dog burial here can be correlated with patterns in human subsistence practices, in particular a reliance on terrestrial mammals. direct radiocarbon dating of a suite of the region's dog remains indicates that these animals were given burial only during periods in which human burials were common. dog burials ...201323696851
quantitative analysis of the interaction of constitutive androstane receptor with chemicals and steroid receptor coactivator 1 using surface plasmon resonance biosensor systems: a case study of the baikal seal (pusa sibirica) and the mouse.the constitutive androstane receptor (car) not only displays a high basal transcriptional activity but also acts as a ligand-dependent transcriptional factor. it is known that car exhibits different ligand profiles across species. however, the mechanisms underlying car activation by chemicals and the species-specific responses are not fully understood. the objectives of this study are to establish a high-throughput tool to screen car ligands and to clarify how car proteins from the baikal seal ( ...201323015691
analysis of thyroid hormones in serum of baikal seals and humans by liquid chromatography-tandem mass spectrometry (lc-ms/ms) and immunoassay methods: application of the lc-ms/ms method to wildlife tissues.thyroid hormones (ths) are essential for the regulation of growth and development in both humans and wildlife. until recently, th concentrations in the tissues of animals have been examined by immunoassay (ia) methods. ia methods are sensitive, but for th analysis, they are compromised by a lack of adequate specificity. in this study, we determined the concentrations of six ths, l-thyroxine (t(4)), 3,3',5-triiodo-l-thyronine (t(3)), 3,3',5'-triiodo-l-thyronine (rt(3)), 3,5-diiodo-l-thyronine (3, ...201122035339
integrative assessment of potential effects of dioxins and related compounds in wild baikal seals (pusa sibirica): application of microarray and biochemical analyses.we have previously indicated that accumulation of chlorinated dioxins and related compounds (drcs) induced cytochrome p450 (cyp) 1a1, 1a2 and 1b1 isozymes in the liver of wild baikal seals (pusa sibirica). here we attempt to assess the potential effects of drcs triggered by the induction of these cyp1 isozymes in this species, using an integrative approach, combining gene expression monitoring and biochemical assays. to screen genes that may potentially respond to the exposure of drcs, we constr ...201121703212
transactivation potencies of the baikal seal (pusa sibirica) peroxisome proliferator-activated receptor α by perfluoroalkyl carboxylates and sulfonates: estimation of pfoa induction equivalency factors.the present study assessed the transactivation potencies of the baikal seal (pusa sibirica) peroxisome proliferator-activated receptor α (bs pparα) by perfluorochemicals (pfcs) having various carbon chain lengths (c4-c12) using an in vitro reporter gene assay. among the twelve pfcs treated with a range of 7.8-250 μm concentration, eight perfluoroalkyl carboxylates (pfcas) and two perfluoroalkyl sulfonates (pfsas) induced bs pparα-mediated transcriptional activities in a dose-dependent manner. to ...201121381677
[cellular composition of the mesenteric lymph node cortex in baikal nerpa during postnatal ontogenesis].cellular composition (relative cell content and cell density) of nodules' germinal centers, mantle zones and paracortical zones was evaluated morphometrically in mesenteric lymph nodes of 65 baikal nerpas (pusa sibirica gmelin) aged 1 month-19 years. a significant decrease in the number of large and medium lymphocytes (3 and 1.9 times, respectively) and reticular cells (2.6 times), was found to occur with age, accompanied by an increase in the number of small lymphocytes (1,5 times) and plasma c ...200819241867
[morpho-functional characteristic of the spleen in baikal seal (pusica sibirica gmel.) pups].using the methods of light microscopy, the histological structure of the spleen in baikal seal (pusica sibirica gmel.) pups was studied for the first time. it was found that in baikal seal the spleen is characterized by highly developed supporting elements (thick capsule and numerous branching trabeculae), which are rich in smooth myocytes. by the age of 2-4 weeks, all the structures of white pulp were formed, however, presence of only a few lymphoid nodules with the absent germinal centers indi ...200617111662
aryl hydrocarbon receptor (ahr) and ahr nuclear translocator (arnt) expression in baikal seal (pusa sibirica) and association with 2,3,7,8-tcdd toxic equivalents and cyp1 expression levels.most toxic effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (tcdd) and related planar halogenated aromatic hydrocarbons (phahs) are mediated by ligand-activated aryl hydrocarbon receptor (ahr) signaling pathway. to understand the regulation mechanism of ahr and ahr nuclear translocator (arnt) expression in wild baikal seal (pusa sibirica) population contaminated by phahs, the present study investigated hepatic mrna expression levels of ahr and its heterodimer, arnt genes, in association with biolo ...200516111922
ct examination of the head of the baikal seal (phoca sibirica).we carried out a computerised tomographic (ct) examination to elucidate the modifications in the head related to orbital enlargement in the baikal seal. transverse ct images showed that (1) the external frontal contours and the frontal sinuses are compressed medially and ventrally by the orbital enlargement; (2) the caudal part of the nasal cavity and nasopharynx are compacted ventrally; and (3) the cranial cavity is displaced caudally. the neurocranium is obviously separated from the facial par ...199910227673
[various ecological and physiological aspects of feeding and growth of the baikal seal pusa sibirica pups]. 200810198996
age-dependent accumulation of heavy metals in baikal seal (phoca sibirica) from the lake baikal.concentrations of fe, mn, zn, cu, cd, and hg were determined in the liver, kidney, and muscle of 60 baikal seals collected from lake baikal in 1992 to investigate age-dependent accumulation. among essential elements, fe concentrations in the muscle, liver, and kidney increased with age, suggesting development of diving ability. the concentrations of mn, zn, and cu decreased with age, especially at immature stages. toxic elements such as hg and cd decreased in adult males and thus the male-female ...19989732486
bioaccumulation profiles of polychlorinated biphenyls including coplanar congeners and possible toxicological implications in baikal seal (phoca sibirica).isomer specific concentrations of individual polychlorinated biphenyls (pcbs) including toxic non-ortho (iupac 77, 126, 169), mono-ortho (105, 118, 156) and di-ortho (137, 138, 153, 180) coplanar congeners were determined in the blubber of 40 baikal seals (phoca sibirica) and as their fish diet collected from lake baikal, siberia. residue levels of total pcbs in baikal seals were noticeably high and comparable to those reported for seals from the north sea, suggesting the recent usage of this co ...199715093474
[the structural characteristics of the auditory portion of the cerebral cortex in the baikal seal (pusa sibirica) and the neuronal reaction to hypoxia].methods of light (nissl, golgi-kopsch) and electron microscopy were used for studying the structural organization of the auditory portion of the cerebral cortex of pusa sibirica. the auditory port of this kind of cortex is characterized by pyramidization of all the layers (layer iv included), thick layer i, two sublayers in layer iii which is typical of other semiaquatic and aquatic mammals. synaptoarchitechtonics of this part of the neocortex may be compared with that of other aquatic, semiaqua ...20061845492
detection of serum antibodies to brucella in russian aquatic mammals.a serologic survey of brucella infection was performed in caspian seals (pusa caspica, n=71), baikal seals (p. sibirica, n=7), ringed seals (p. hispida hispida, n=6), and beluga whales (delphinapterus leucas, n=4) inhabiting russian waters, by enzyme-linked immunosorbent assay (elisa) using brucella abortus and b. canis as antigens. the sera of 4 caspian seals (4%) tested positive for b. abortus. the same sera samples demonstrated weaker yet detectable affinity for b. canis antigens. several dis ...201830185724
freshwater seal as a source of direct and indirect increased human exposure to persistent organic pollutants in a background area.the aim of the study is to investigate pop levels in environmental media (air, snow, soil and sediment), certain food items in the olkhon district (irkutsk region, russia) and lake baikal seal (nerpa) fat and meat in order to define the main pathways of elevated human exposure to pops in the area. pop levels in soil and air samples and in almost all of the food items from the olkhon district were comparable to levels in background areas of the lake baikal region. only certain chicken eggs, large ...202032041048
mercury loading within the selenga river basin and lake baikal, siberia.mercury (hg) loading in lake baikal, a unesco world heritage site, is growing and poses a serious health concern to the lake's ecosystem due to the ability of hg to transform into a toxic form, known as methylmercury (mehg). monitoring of hg into lake baikal is spatially and temporally sparse, highlighting the need for insights into historic hg loading. this study reports measurements of hg concentrations from water collected in august 2013 and 2014 from across lake baikal and its main inflow, t ...202032023784
the canine morbillivirus strain associated with an epizootic in caspian seals provides new insights into the evolutionary history of this virus.canine morbillivirus (canine distemper virus; cdv) is a worldwide distributed morbillivirus that causes sporadic cases and recurrent epizootics among an increasing number of wild, feral, and domestic animal species. we investigated the evolutionary history of cdv strains involved in the 1988 lake baikal (cdvps88) and the 2000 caspian sea (cdvpc00) seal die-offs by recovery of full-length sequences from archived material using next-generation sequencing. bayesian phylogenetic analyses indicated t ...201931557833
in vitro assessment of effects of persistent organic pollutants on the transactivation of estrogen receptor α and β (erα and erβ) from the baikal seal (pusa sibirica).to assess the effect of exposure to persistent organic pollutants (pops) on the estrogen receptor (er) signaling pathway in baikal seals (pusa sibirica), we investigated the molecular characterizations and functions of two baikal seal er (bser) isoforms, bserα and bserβ. the bserα and bserβ cdna clones isolated have an open reading frame of 595 and 530 amino acid residues, respectively. the tissue distribution analyses of bser mrnas showed that bserα transcripts were primarily found in the ovary ...201931228822
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