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At least 865 records · Page 48Linked to original sources
PubMed2004

Characterization of oligosaccharides in milk of bearded seal (Erignathus barbatus).

Carbohydrates were extracted from milk of a bearded seal, Erignathus barbatus (Family Phocidae). Free neutral oligosaccharides were separated by gel filtration, anion-exchange chromatography and preparative thin layer chromatography, while free acidic oligosaccharides were separated by gel filtration and then purified by ion exchange chromatography, gel filtration and high performance liquid chromatography. Oligosaccharide structures were determined by 1H-NMR spectroscopy. The structures of the neutral oligosaccharides were as follows; lactose, 2'-fucosyllactose, lacto-N-fucopentaose IV, difucosyl lacto-N-neohexaose and difucosyl decasaccharide which contained a lacto-N-neohexaose unit as well as an additional Gal(beta1-4)GlcNAc(beta1-3) unit and two residues of non-reducing Fuc(alpha1-2). The acidic oligosaccharides were thought to contain an Neu5Ac(alpha2-6) residue linked to GlcNAc or a sulfate linked to Gal at OH-3. The sialyl oligosaccharides and sulfated oligosaccharides had a lacto-N-neohexaose unit and two non-reducing Fuc(alpha1-2) residues and some of them had in addition one or two Gal(beta1-4)GlcNAc(beta1-3) units. The milk oligosaccharides of the bearded seal were compared to those of the harbour seal, which had been studied previously.

Animals↗
PubMed2005

Characterisation of proteins in the milk of fur seals.

Milk protein composition was investigated throughout the lactation periods of the Australian fur seal (Arctocephalus pusillus doriferus) and Antarctic fur seal (Arctocephalus gazella). The mean protein content of the milk was found to be 10.9% and 10.6% respectively. The concentration of total protein did not change during lactation, although a decline in casein content of the milk in late lactation was apparent. Milk protein concentration during a foraging/suckling cycle of the Antarctic fur seal analysed at the time of arrival on shore, and 24 h and 72 h after arrival was 12.8%, 11.4% and 12.5% respectively. Re-feeding animals at 72 h resulted in a significant increase in milk protein content to 14.9%. Characterisation of milk protein by SDS-PAGE analysis revealed 5 casein and 10 major whey protein bands. Amino-terminal sequencing indicated that the majority of the whey fraction of the milk is beta-lactoglobulin (beta-LG). The limited amino acid sequence indicated 3 different beta-LGs were secreted in the milk. Subsequently, RT-PCR was used to extend the sequence of one of the beta-LGs and translation of the 464 bp fragment indicated that it shared 79% sequence identity with feline beta-LG II.

Amino Acid Sequence↗
PubMed2005

Polybrominated diphenyl ethers and selected organochlorine chemicals in grey seals (Halichoerus grypus) in the North Sea.

Blubber samples from grey seal (Halichoerus grypus) pups were collected in 1998 through to 2000. Twenty four newly weaned pups were sampled in November 1998, 13 of which were re-sampled during their first year of life, between March and December 1999, and an additional 48 and 25 samples (new cohorts) were obtained in 1999 (November-December) and 2000 (May-September) respectively. SimgaPBDE concentrations (sum of Di-HxBDEs) ranged from 45 to 1500 ng/g lipid, with a geometric mean of 290 ng/g lipid. BDE 47 dominated the congener profile, followed by BDEs 100, 99, 153 and 154. SimgaPCB concentrations (sum of 41 congeners) ranged from 100 to 93000 ng/g lipid, with a geometric mean of 4600 ng/g lipid, with CB congeners 153, 138 and 180 making up 84% of the total PCB concentrations. The predominant OC pesticides were p,p'-DDE (geometric mean=860 ng/g lipid, range=160-3800 ng/g lipid) and p,p'-DDT (geometric mean=120 ng/g lipid, range=30-670 ng/g lipid). No significant differences were found between males and females, probably due to the young age of the animals. Significant decreases (P<0.01 for PBDEs and P<0.05 for PCBs/OCs) were observed between newly weaned seals in 1998 and 1999, but not for the majority of juveniles in 1999 and 2000. Significant differences (P<0.01) were also found between the different seasons in 1999 newly weaned and juvenile seals, reflecting changes in blubber mass.

Adipose Tissue↗
PubMed2003

Determination of atropisomeric and planar polychlorinated biphenyls, their enantiomeric fractions and tissue distribution in grey seals using comprehensive 2D gas chromatography.

High prevalence of uterine occlusions and sterility is found among Baltic ringed and grey seal. Polychlorinated biphenyls (CBs) are suspected to be the main cause. The CB concentrations are higher in affected than in healthy animals, but the natural variation is considerable. Thus, it might be possible to assess the health status of seals by CB analysis. The ratios of chiral compounds (enantiomeric fractions (EFs)) such as atropisomeric CBs are of particularinterest, since these may reflect differences in metabolic rates. An analytical procedure was developed and used to determine the levels of atropisomeric CBs, planar-CBs (WHO-PCBs) and total CBs in seals of different health status. Comprehensive 2D gas chromatography (GC x GC) was used to separate the target analytes from other CBs and interferences and a micro electron-capture detector (microECD) was used for detection. EFs of the atropisomeric CBs were difficult to determine as the levels were low and the interferences many. Two column combinations bad to be used to avoid biased results-both had a chiral column as first-dimension column. The second-dimension column was coated with either a high-polarity cyanopropyl or a liquid crystal phase. EFs were determined for five atropisomeric CBs, i.e. CBs 91,95, 132, 149 and 174. The results were verified by GC x GC-time-of-flight mass spectrometry (TOF-MS). Some atropisomeric CBs had EFs that deviated strongly from the racemic-mixture value. The deviations were larger in liver than blubber, which indicates enantioselective metabolism. However, there was no selective passage of the studied atropisomeric CBs across placenta and no selective blood-brain barrier. Similarly, no correlation between EFs and health status was observed, although there was a correlation between the total CB levels and health status.

Animals↗
PubMed2006

Experiments directed to the compound-specific determination of the stable carbon isotope ratios of the Toxaphene congener B8-1413 in two technical mixtures and Antarctic Weddell seal.

The carbon stable isotope ratio (delta(13)C value) of an environmentally-relevant Toxaphene congener in technical products and a biological sample from a remote region was in the focus of this work. For this reason, the major octachlorobornane residue of the multicomponent pesticide Toxaphene in biological samples, 2-endo,3-exo,5-endo,6-exo,8,8,10,10-octachlorobornane (B8-1413 or P26), was quantitatively enriched from two technical Toxaphene mixtures (Toxaphene and Melipax) in duplicates as well as from an Antarctic Weddell seal sample. Normal phase followed by reversed-phase high-performance liquid chromatography (HPLC) with three columns, respectively, coupled in series was used for this purpose. Four of the five fractionated samples fulfilled the requirement of an interference-free GC-elution for subsequent determination of the delta(13)C value by gas chromatography interfaced to an isotope ratio mass spectrometer (GC-IRMS). B8-1413 in Toxaphene (n=1) was more depleted in (12)C than in Melipax (n=2), which agrees with previous results obtained for the entire mixtures. The B8-1413 isolate from a Weddell seal sample from the Antarctic showed a delta(13)C value between the two technical products. Although a source appointment to the one or the other product was not possible, this example indicates that long range transport to the Antarctic and by uptake and food-chain bioaccumulation of B8-1413 in seals did not change the delta(13)C value significantly. The observed differences in one duplicate sample indicate that statistic evaluation of samples used for isotope ratio MS measurements is an important issue.

Animals↗
PubMed2006

In vitro and in vivo replication of seal gammaherpesviruses in cells of multiple species.

Phocid herpesvirus virus type 2 (PhHV-2), a putative gammaherpesvirus of seals, has been isolated from harbor seals (Phoca vitulina) and grey seals (Halichoerus grypus). In the present study, different PhHV-2 isolates were shown to have a broad in vitro tropism for various cell types from several mammalian species. Inbred mice and two species of non-human primates proved to be susceptible to experimental infection with PhHV-2. The development of myoepitheliomas and spleen hyperplasia upon cyclosporin A treatment in some of the PhHV-2-infected animals warrants further investigation of the oncogenic and zoonotic potential of this virus.

Animals↗
PubMed2006

A 1500-year record of lead, copper, arsenic, cadmium, zinc level in Antarctic seal hairs and sediments.

To reconstruct the profiles of heavy metal levels in the South Ocean ecosystem of Antarctica, the concentrations of lead (Pb), copper (Cu), arsenic (As), cadmium (Cd), and zinc (Zn) in seal hairs and lake sediments spanning the past 1500 years from Fildes Peninsula of King George Island and in weathering lake sediments from Nelson Island of West Antarctica were determined. The lead contents in the seal hairs and the weathering sediments show a sharp increase since the late 1800s, very likely due to anthropogenic contamination from modern industries. After the 1980s, the Pb content in seal hairs dropped by one-third, apparently due to the reduced usage of leaded gasoline in the Southern Hemisphere. Copper arises mainly from the weathering process, and its level may be substantially affected by climatic conditions. The concentrations of Cd, As, and Zn do not show any clear temporal trends.

Animals↗
PubMed2004

Fecal shedding of Helicobacter spp. by co-housed Australian sea lions (Neophoca cinerea) and Australian fur seals (Arctocephalus pusillus doriferus).

With the emergence of Helicobacter species as agents of gastrointestinal disease within a broad range of animal hosts, there is growing awareness of the need to identify such species and the potential role(s) they play within the intestine. Of interest in this study are captive seals and sea lions, where close proximity to one another may enhance the transmission of pathogens, in particular Helicobacter. The feces of several captive Australian sea lions and Australian fur seals were assessed for the occurrence of Helicobacter over 31 days. The presence of Helicobacter, detected by the polymerase chain reaction (PCR) varied over time and at times could not be detected. Helicobacter species were detected in five of the six animals examined of which two species were identified. This is the first report of Helicobacter species in captive seals and demonstrates the diversity and potential role(s) they may play in the gut of these animals.

Animals↗
PubMed2004

Diurnal patterns of cortisol and thyroid hormones in the Harbor seal (Phoca vitulina) during summer and winter seasons.

A leading hypothesis for the dramatic population decline of the Alaskan harbor seal over the last 2-3 decades have related environmental changes to a decrease in the quality or quantity of available prey. If harbor seals are experiencing some sort of nutritional stress, it is important to understand the physiological and endocrine mechanisms controlling metabolic homeostasis in this species. The purpose of this research project was to determine whether circadian patterns of cortisol and total and free thyroxine (T(4)) and triiodothyronine (T(3)) are present in the harbor seal during the summer and winter seasons, and identify how they might alter metabolic rate and maintenance of body reserves. This study was carried out at the Alaska SeaLife Center in Seward, Alaska in June 2000 and January 2001. Blood samples were obtained every 2-3 h over a 24-h period through in-dwelling catheters inserted the day before sampling. The presence of a diurnal rhythm was determined by comparing levels between ante meridian (12 am to noon) and post meridian (noon to 12 midnight) time periods. Mean daily cortisol concentrations were not significantly different between seasons, but cortisol displayed a circadian rhythm only during the summer. Mean concentrations of cortisol (51.5 ng/ml+/-20.3) in the summer hours of ante meridian differed significantly from levels in the hours of post meridian (28.5 ng/ml+/-17.4). Neither total and free T(4), nor T(3), displayed a diurnal rhythm in either season. However, tT(4), tT(3), and fT(3) levels were significantly higher in the winter than in the summer. There was no seasonal effect on fT(4) levels. The absence of a circadian rhythm of cortisol during the winter may have been a result of the limited amount of daylight as well as the continual need to produce metabolic heat as a by-product of gluconeogenesis. Higher levels of thyroid hormones in the winter indicate an adaptive mechanism to cope with the low temperatures of winter.

Aging↗
PubMed2003

Negative relationship between PCBs and plasma retinol in low-contaminated free-ranging gray seal pups (Halichoerus grypus).

Polychlorinated biphenyls (PCBs) have been shown to affect retinol (vitamin A) homeostasis in adult as well as neonatal seals. The aim of the present study was to examine the relationships between plasma (PL)-retinol status and PCB concentrations in different blood compartments (blood cells (BCs), PL, and whole blood (WB)) of free-ranging neonatal gray seals (Halichoerus grypus) and to identify which PCB congeners may be responsible for the PL-retinol-depressing effects of PCBs. PL-retinol concentrations correlated positively with body mass and negatively with sigmaPCB (lipid-weight basis, lw) in WB and sigmaPCBlw in BCs. SigmaPCBlw in WB was the parameter that best described the variation in PL-retinol concentration (r2=0.455, n=20, P=0.0007). Furthermore, PL-retinol concentrations correlated with nine of the 15 detected PCB congeners. It is possible that there is an equilibration between the concentrations of metabolizable congeners and their metabolites and that the retinol-depressing effect of PCBs in neonatal gray seals is caused by PCB-OH metabolites that interfere with the formation of PL transport complexes that transport retinol in PL and increase renal excretion of retinol. This suggestion is in accordance with previous mechanistic explanations of the retinol-depressing effect of PCB in rodents.

Animals↗
PubMed1990

Histopathological findings in harbour seals (Phoca vitulina) found dead on the German North sea coast.

Various organs--lung, trachea, liver, kidney, heart, adrenal gland, skin, spleen, thymus, lymph node, gut, thyroid, spinal cord and brain--were removed from 43 seals at dissections performed on the German North sea coast. The specimens were fixed in formalin and routinely processed for light microscopy. The major pathological findings were Lung: acute congestion with interstitial and intra-alveolar oedema; intra-alveolar haemorrhage; suppurative bronchitis and bronchopneumonia; larvae and adult forms of Parafilaroides gymnurus. Liver: acute congestion; granulomatous lesions and infiltrates of eosinophils; intravascular nematodes. Spleen: varying degrees of atrophy of the white pulp; haemosiderosis; acute congestion of the red pulp. Lymph nodes: varying degrees of atrophy of the lymphatic tissue; long-standing sinus histiocytosis with partial fibrotic obliteration of the lumina; parasitic infiltration, sometimes with the Splendore-Hoeppli phenomenon; germinal centre hyperplasia. Thymus: pronounced atrophy of the lymphatic tissue, particularly in the cortical areas. Thyroid: marked reduction in colloid content. The other organs studied were normal or showed only minor histopathological changes. The morphological findings do not allow definite conclusions to be made about the aetiology and pathogenesis of the illness and death of the seals. However, evidence has been published that the seals' illness is probably due to canine distemper virus. The atrophy of the lymphoreticular tissues is consistent with infection by this virus.

Animals↗
PubMed1997

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.

Animals↗
PubMed1997

Cytochromes P450, P420 & mixed-function oxidases as biomarkers of polychlorinated biphenyl (PCB) exposure in harbour seals (Phoca vitulina).

Hepatic microsomal cytochrome P450, EROD and ECOD activity were investigated as biomarkers of PCB exposure in harbour seals (Phoca vitulina). Due to the difficulty of obtaining undegraded seal liver samples, standard spectrophotometric methodology was adapted to investigate P420 (degraded P450) as a PCB biomarker with partially degraded samples. Total PCB burdens in both blubber and liver had positive correlations with P450, P420 and MFO activity levels. The use of P420 biomarkers in this study supports the inclusion of samples from by-caught marine mammals for future biomonitoring studies. P450 isozymes CYP1A (P4501A) and CYP2B (P4502B) in conjunction with MFO activity were investigated as "specific" biomarkers of PCB exposure. They were found to reliably reflect levels of [MC] and [PB]-type PCB exposure in harbour seal liver.

Adipose Tissue↗
PubMed1997

Harbor seal (Phoca vitulina) C-reactive protein (C-RP): purification, characterization of specific monoclonal antibodies and development of an immuno-assay to measure serum C-RP concentrations.

C-reactive protein (C-RP) was purified from harbor seal (Phoca vitulina) serum by calcium dependant phosphoryl-choline and protein A affinity chromatography. Polyacrylamide gel electrophoresis under reducing conditions revealed a single protein moiety with a molecular weight of approximately 25 kDa. An internal peptide derived from this purified protein was subjected to N-terminal amino acid sequencing. A high amino acid sequence similarity was obtained with other published mammalian C-RP molecules confirming that the purified protein was a C-RP homologue. Eight specific monoclonal antibodies (P13, P51, P87, P101, P106, P130, P157 and P219) were raised against this purified protein. All 8 monoclonal antibodies immunoblotted with the 25 kDa C-RP subunit under reducing conditions. A competitive immunoassay was developed identifying elevated C-RP concentrations in harbor seal serum samples with clinical evidence of inflammatory disease. Application of this immunoassay for the measurement C-RP may provide valuable information for the clinical assessment of harbor seal health.

Acute-Phase Reaction↗
PubMed2002

Polychlorinated naphthalenes and coplanar polychlorinated biphenyls in beluga whale (Delphinapterus leucas) and ringed seal (Phoca hispida) from the eastern Canadian Arctic.

Blubber collected from beluga whales and ringed seals during subsistence hunts in the southern Baffin Island region of the Canadian Arctic were analysed for polychlorinated naphthalenes and eight planar PCB congeners (mono-ortho PCBs: 105, 114, 118 and 156; non-ortho PCBs: 77, 81, 126, 169). SigmaPCN (3-7 Cl) concentrations in blubber ranged from 35.9-383 pg/g (lipid weight; lw) in beluga and 35.4-71.3 pg/g (lw) in ringed seal. These represent the first measurements of PCNs in marine mammals in the Canadian Arctic, mammals which are an important part of the traditional diet of the indigenous population. SigmaCoplPCB concentrations were much higher, ranging from 15.5-317 ng/g (lw) in beluga whale blubber and 16.5-40.9 ng/g (lw) in ringed seal blubber. PCNs and coplanar PCBs both exhibit dioxin-like toxicity. Although average sigmaPCN concentrations were less than 1% of sigmaCoplPCBs, PCNs contribute up to 11% of TEQ relative to the coplanar PCBs based on TEFs determined by H4IIE enzyme assays.

Adipose Tissue↗
PubMed2003

Polybrominated diphenyl ethers (PBDEs) in grey seals during their first year of life--are they thyroid hormone endocrine disrupters?

Blubber biopsy and blood samples were collected from weaned grey seal pups and juveniles in 1998 and 1999. The relationship between the concentration of total PDBEs in the blubber and the circulating concentrations of serum proteins, minerals and thyroid hormones was investigated. Fifty-four post-weaned pups were sampled and 55 first year juveniles, of which 13 were recaptured post-weaned pups. The median concentration of total PBDEs in the pups' blubber was 170 and 460 ng g(-1) in the first-year animals. Total blubber PBDEs contributed significantly to the prediction of circulating thyroid hormone concentrations, after controlling for age and condition. Cholesterol and albumin concentrations were also positively related to blubber PBDEs. The results of this study suggest a link between thyroid hormones and exposure to PBDEs in grey seals during their first year of life. Such an association is not alone sufficient evidence for a cause and effect relationship, however it is in accordance with the hypothesis that these compounds are endocrine disrupters in grey seal pups.

Adipose Tissue↗
PubMed2001

Humoral immune responses to phocine herpesvirus-1 in Pacific harbor seals (Phoca vitulina richardsii) during an outbreak of clinical disease.

Infection with phocine herpesvirus type-1 (PHV-1) has been associated with morbidity and high mortality in neonatal harbor seals (Phoca vitulina). A PHV-1 specific indirect enzyme linked immunosorbent assay (ELISA) was developed to sequentially measure the serological status of 106 harbor seal neonates admitted to a Pacific coast rehabilitation center (total number of sera tested was 371). Early in the season (February-April), the majority of pups had low serum levels of PHV-1 specific antibody. A dramatic increase in PHV-1 specific antibody, involving the majority of hospitalized pups, was observed during a 4-week period in May. This coincided with a high incidence of PHV-1 associated adrenal lesions and mortality. Although there was overall agreement between the timing of seroconversion to PHV-1 and histological evidence of PHV-1 infection, 82.4% of individual pups with adrenalitis had no evidence of a humoral response to PHV-1 at the time of their death. This suggests either a rapid disease course, or an inability to develop a humoral response in some neonatal seals.

Animals↗
PubMed1999

Pharmacokinetics of intravenously administered ketamine in southern elephant seals (Mirounga leonina).

Southern elephant seals (Mirounga leonina) are large, potentially dangerous animals which must be restrained before study or treatment. However, chemical restraint is unpredictable, possibly because of differences in body composition during fasting ashore, and circulatory adaptations to enable diving. The pharmacokinetics of ketamine (1.1 mg/kg i.v.) was studied in 15 southern elephant seals which had come ashore on Macquarie Island. The animals were first sedated with pethidine (5 mg/kg i.m.) to allow intravenous access. There was great variability in the calculated pharmacokinetic parameters, possibly due to circulatory changes associated with periods of apnoea which characterise this animal's response to anaesthetics. The median values were similar to those reported for other species: distribution t1/2 = 2.5 min (range 1-11 min); elimination t1/2 = 43 min (range 17-108 min); apparent volume of distribution, 1474 ml/kg (range 830-9301 ml/kg); clearance, 33 ml/min/kg (range 12-57 ml/min/kg). This was the first investigation of drug disposition in any seal species. and the first in any free-ranging wild animal. It is important to obtain pharmacological data in animals in whom drugs are used, but pre-catheterised captive animals may provide less variable data.

Anesthetics, Dissociative↗