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At least 631 records · Page 35Linked to original sources

PubMed2006

Distribution of total mercury, methyl mercury and selenium in pod of killer whales (Orcinus Orca) stranded in the northern area of Japan: comparison of mature females with calves.

Total mercury (T-Hg) and selenium (Se) concentrations in liver, kidney and muscle from a pod of killer whales including five mature females and three calves stranded in the northern area of Japan were analyzed. In the mature female, contamination level of T-Hg in the liver sample (62.2+/-21.9 microg/wet g) was markedly higher than that in kidney sample and muscle sample. The molar ratio of T-Hg to Se in the liver sample was approximately 1, and those in the kidney and muscle samples were markedly lower than 1. These results suggest that the formation of HgSe compound increases the hepatic accumulation of mercury (Hg). In contrast, contamination level of T-Hg in the calf organs was much lower than that in the mature female organs. These results suggest that the transfer of Hg from the mother to the fetus via placenta and/or to calf via milk is trace.

Aging↗

PubMed2005

Immunochemical detection of nitric oxide and nitrogen dioxide trapping of the tyrosyl radical and the resulting nitrotyrosine in sperm whale myoglobin.

We demonstrate herein that nitric oxide (*NO) and nitrogen dioxide (*NO2) both react with the tyrosyl radical formed in sperm whale myoglobin (swMb) by reaction with hydrogen peroxide. The tyrosyl radical was detected by Western blotting using a novel anti-5,5-dimethyl-1-pyrroline N-oxide (DMPO) polyclonal antiserum that specifically recognizes protein radical-derived DMPO nitrone adducts. In the presence of DMPO, hydrogen peroxide reacts with swMb to form the DMPO tyrosyl radical as is known from both electron spin resonance and immuno-spin trapping investigations. Both *NO and NO2- significantly suppressed DMPO-Mb formation under the physiological oxygen tension of 30 mm Hg. If this inhibition of DMPO trapping of the tyrosyl radical is due, at least in part, to the reaction of the tyrosyl radical with *NO and *NO2, then nitrotyrosine should be formed. In line with this expectation, swMb treated with low concentrations of *NO or NO2- formed nitrotyrosine when hydrogen peroxide was added under 30 mm Hg oxygen tension as detected by Western blotting. The amount of nitrotyrosine generated with *NO was higher than with NO2-, implying that there are two different peroxynitrite-independent nitrotyrosine formation mechanisms and that *NO is not just a source of *NO2.

Aerobiosis↗

PubMed2004

Concentrations of organochlorines in sperm whales (Physeter macrocephalus) from Southern Australian waters.

Concentrations of DDTs, PCBs and HCHs were measured in sperm whales involved in two mass stranding events on the west coast of Tasmania, Australia in February 1998. DDTs and PCBs were present in all samples analysed, while only three contained HCHs. The relationships between organochlorines, sex, age and reproductive groups were marked by high variability. Differences in organochlorine concentrations were observed between animals from the two stranding sites and discussed in light of the ecology of this species. Concentrations of all pollutants were stratified throughout the vertical aspect of the blubber and possible reasons for and the implications of this are discussed. Concentrations of compounds were higher than those documented in this species in the Southern Hemisphere previously, although were relatively lower than those documented in the Northern Hemisphere. However, comparisons were confounded by spatial and temporal differences. Continued monitoring of marine mammals throughout this region in a co-coordinated, standardized manner is essential for establishing definite temporal and spatial variations in pollutant concentrations.

Adipose Tissue↗

PubMed2003

Primary folding dynamics of sperm whale apomyoglobin: core formation.

The structure, thermodynamics, and kinetics of heat-induced unfolding of sperm whale apomyoglobin core formation have been studied. The most rudimentary core is formed at pH(*) 3.0 and up to 60 mM NaCl. Steady state for ultraviolet circular dichroism and fluorescence melting studies indicate that the core in this acid-destabilized state consists of a heterogeneous composition of structures of approximately 26 residues, two-thirds of the number involved for horse heart apomyoglobin under these conditions. Fluorescence temperature-jump relaxation studies show that there is only one process involved in Trp burial. This occurs in 20 micro s for a 7 degrees jump to 52 degrees C, which is close to the limits placed by diffusion on folding reactions. However, infrared temperature jump studies monitoring native helix burial are biexponential with times of 5 micro s and 56 micro s for a similar temperature jump. Both fluorescence and infrared fast phases are energetically favorable but the slow infrared absorbance phase is highly temperature-dependent, indicating a substantial enthalpic barrier for this process. The kinetics are best understood by a multiple-pathway kinetics model. The rapid phases likely represent direct burial of one or both of the Trp residues and parts of the G- and H-helices. We attribute the slow phase to burial and subsequent rearrangement of a misformed core or to a collapse having a high energy barrier wherein both Trps are solvent-exposed.

Animals↗

PubMed1980

Electrostatic stabilization in sperm whale and harbor seal myoglobins. Identification of groups primarily responsible for changes in anchoring of the A helix.

The compact, largely helical structure of sperm whale and harbor seal myoglobins undergoes an abrupt one-step transition between pH 4.5 and 3.5 as monitored by changes in either the heme Soret band absorbance or circular dichroism probes of secondary structure, for which a modified Tanford-Kirkwood theory provides identification of certain dominant electrostatic interactions responsible for the loss of stability. A similar treatment permits identification of the electrostatic interactions primarily responsible for a process in which the anchoring of the A helix to other parts of the molecule is weakened. This process is detected with both myoglobins, in a pH range approximately 1 unit higher than the onset of the overall unfolding process, through changes in the circular dichroic spectra near 295 nm which correspond to the L1 O-O band of the only two tryptophan residues in these proteins, residues 7 and 14. In each case protonation of certain sites in neighboring parts of the molecule can be identified as producing destabilizing interactions with components of the A helix, particularly with lysine 6.

Animals↗

PubMed1993

Solution 1H nuclear magnetic resonance determination of the distal pocket structure of cyanomet complexes of genetically engineered sperm whale myoglobin His64 (E7)-->Val, Thr67 (E10)-->Arg. The role of distal hydrogen bonding by Arg67 (E10) in modulating ligand tilt.

Sequence-specific 2D methodology has been used to assign the 1H NMR signals for all active site residues in the paramagnetic cyano-met complexes of sperm whale synthetic double mutant His64[E7]-->Val/Thr67[E10]-->Arg (VR-met-MbCN) and triple mutant His64[E7]-->Val/Thr67[E10]-->Arg/Arg45[CD3]-->Asn (VRN-metMbCN). The resulting dipolar shifts for noncoordinated proximal side residues were used to quantitatively determine the orientation of the paramagnetic susceptibility tensor in the molecular framework for the two mutants, which were found indistinguishable but distinct from those of both wild-type and the His64[E7]-->Val single point mutant (V-metMbCN). The observed dipolar shifts for the E helix backbone protons and Phe43[CD1], together with steady-state nuclear Overhauser effect between the E helix and the heme, were analyzed to show that both the E helix and Phe43[CD1] move slightly closer to the iron to minimize the vacancy resulting from the His64[E7]-->Val substitution, as found in V-metMbCN (Rajarathnam, K., J. Qin, G.N. LaMar, M. L. Chiu, and S. G. Sligar. 1993. Biochemistry. 32:5670-5680). The dipolar shifts of the mutated Val64[E7] and Arg67[E10] allow the determination of their orientations relative to the heme, and the latter residue is shown to insert into the pocket and provide a hydrogen bond to the coordinated ligand, as found in the naturally occurring ValE7/ArgE10 genetic variant, Aplysia limacina Mb. The oxy-complex of both A. limacina Mb and VR-Mb, VRN-Mb have been proposed to be stabilized by this hydrogen bonding interaction (Travaglini Allocatelli, C. et al. 1993. Biochemistry. 32:6041-6049). The magnitude of the tilt of the major magnetic axes from the heme normal in VR-metMbCN and VRN-metMbCN, which is related to the tilt of the ligand, is the same as in wild-type or V-metMbCN, but the direction of tilt is altered from that in V-metMbCN. It is concluded that the change in the direction of the ligand tilt in both the double and triple mutants, as compared to WT metMbCN and V-metMbCN single mutant, is due to the attractive hydrogen-bonding between ArgE10 and the bound cyanide.

Amino Acid Sequence↗

PubMed1978

A typical dermatan sulfate isolate from whale intestine.

Alkaline extraction of whale intestine, followed by pronase digestion and precipitation of heparin (omega-heparin) with dodecyltrimethylammonium chloride gave a supernatant fraction containing dermatan sulfate. Ethanol at 20% concentration precipitated dermatan sulfate from the supernatant fraction. The crude dermatan sulfate was further fractionated by ion-exchange column chromatography on Dowex-1 (C1- form), eluting stepwise with aqueous sodium chloride. The fractions eluted with 1.5M and 1.75M sodium chloride contained a typical dermatan sulfate. Chemical and enzymic studies of these preparations revealed that the sulfate groups were located solely at O-4 of the 2-acetamido-2-deoxy-D-galactose resides. L-Iduronic acid was assumed to be distributed uniformly in the backbone of the polysaccharide chain, with D-glucuronic acid being located in the linkage region to the protein core. A new method for determining the ratio of D-glucuronic to L-iduronic acid is also described.

Animals↗

PubMed1998

Naturally occurring ganglioside lactones in Minke whale brain.

Ganglioside lactones in Minke whale brain were analysed. In order to exclude the possibility of the artificial lactonization of gangliosides during the analytical procedures, lactone species were separated from their parent gangliosides at an early stage by DEAE-Sephadex A-25 column chromatography using a stepwise elution. Applying the improved method, GM41 lactones were found in grey and white matters of cerebrum and cerebellum, while GD3 monolactone was found only in cerebellar gray matter. The concentration of each ganglioside lactone was one thousandth of the parent ganglioside.

Animals↗

PubMed1995

Non-neoplastic lesions in beluga whales (Delphinapterus leucas) and other marine mammals from the St Lawrence Estuary.

In a 3-year (1988-1990) pathological study, 24 carcasses of beluga whales from the St Lawrence Estuary, Québec, Canada, showed numerous severe lesions, many of which had never been reported in cetaceans. The most common lesions were found in the digestive tract (21 animals) and consisted mainly of periodontitis and of erosions and ulcers in the oesophagus and the first two gastric compartments. Pneumonia, usually of parasitic origin, was also a common finding (12 animals). The adrenal glands often contained nodules (five animals) or cysts (seven animals), and mastitis was observed in five females. Overall, the incidence of degenerative, infectious, hyperplastic or necrotic lesions, in addition to numerous neoplasms described in another paper, was considerably higher than that found in marine mammals elsewhere or in other species of marine mammal from the same waters.

Animal Diseases↗

PubMed1983

Heme orientational disorder in reconstituted and native sperm whale myoglobin. Proton nuclear magnetic resonance characterizations by heme methyl deuterium labeling in the Met-cyano protein.

The solution proton nuclear magnetic resonance spectrum of the Met-cyano form of sperm whale myoglobin reveals the presence of two sets of comparably intense resonances immediately after reacting the apoprotein with hemin, only one of which corresponds to that of the accepted native protein. Isotope labeling of individual methyl groups of hemin reveals that the methyl assignments differ characteristically in that similar resonance positions for the two components arise from the methyl groups related by a 180 degrees rotation about the alpha-gamma-meso axis. This phenomenon, observed earlier only for myoglobin with modified hemin, dictates that the second protein component in solution immediately after reconstitution must have the heme rotated by 180 degrees about the alpha-gamma-meso axis as compared to that found in the single crystal. The two components in the reconstituted protein equilibrate to yield the spectrum of the native Met-cyanomyoglobin for which there still exists approximately 8% of the minor component. Thus native myoglobin in solution is structurally heterogeneous in the heme pocket. Proton nuclear magnetic resonance spectra of deoxymyoglobin produced from both native and freshly reconstituted protein shown that the heterogeneity is also a property of the physiologically relevant reduced protein forms. It is suggested that, contrary to available X-ray data, heme orientational heterogeneity may be the rule rather than the exception in b-type hemoproteins, and that such disorder must be carefully considered in detailed correlations between structure and function even in native hemoproteins.

Animals↗

PubMed1998

Relationship between organochlorine contaminants and mixed function oxidase activity in skin biopsy specimens of Mediterranean fin whales (Balaenoptera physalus).

The relationship between organochlorine contaminants (PCBs and DDTs) and mixed function oxidase, benzo(a)pyrene monooxigenase activity (BPMO), was investigated in skin biopsy specimens from fin whales (Balaenoptera physalus) of the Mediterranean Sea. Skin biopsy material, sampled by a non invasive technique, is suitable for a wide range of chemical and biomarker analysis. In this study PCBs and DDTs were evaluated in subcutaneous blubber and MFO activity in epidermis. An interesting correlation was found in male specimens between the two variables.

Animals↗

PubMed2002

Mercury and selenium concentrations in the internal organs of toothed whales and dolphins marketed for human consumption in Japan.

Small cetaceans (toothed whales odontoceti and dolphins delphinidae) have been traditionally hunted along the coast of Japan and fresh red meat and blubber, as well as boiled internal organs such as liver, kidney, lung and small intestine, are still being sold for human consumption. We surveyed mercury contamination in boiled liver, kidney and lung products marketed in Japan between 1999-2001. The average +/- S.D. of total mercury (T-Hg) was 370 +/- 525 (range: 7.60 approximately 1980, n = 26) microg/g in liver, 40.5 +/- 48.5 (7.30-95.1, n = 15) microg/g in kidney and 42.8 +/- 43.8 (2.10-79.6, n = 23) microg/g in lung. A high correlation was observed between T-Hg and selenium (Se) concentrations in these organs, supporting the formation of a Hg-Se complex. The formation of a Hg-Se complex probably contribute to the detoxification of Hg for cetaceans and allows a very large accumulation of Hg in livers. The provisional permitted level of T-Hg in marine foods set by the Japanese Ministry of Health and Welfare is 0.4 microg/ g, and the provisional permitted weekly intake (PTWI) set by WHO is 5 microg/kg bw/week. The maximal T-Hg detected in boiled liver (1,980 microg/g) exceeds the permitted level by approximately 5,000 times and the consumption of only 0.15 g of liver exceeds the PTWI of 60 kg of body weight of the consumer, suggesting the possibility of an acute intoxication by T-Hg even after a single consumption of the product.

Animals↗

PubMedDate not supplied

Multi-trial biomarker approach in Meganyctiphanes norvegica: a potential early indicator of health status of the Mediterranean "whale sanctuary.".

The aim of this study was to propose a suite of biomarkers (BPMO activity, NADPH-cytocrome c reductase, NADH-ferricyanide reductase. esterases, porphyrins, vitellogenin and zona radiata proteins) and residue levels (organochlorines, PAHs and heavy metals) in the zooplanktonic euphausiid Meganyctiphanes norvegica as a potential multi-disciplinary diagnostic tool for assessment of the health status of the Mediterranean "whale sanctuary". Very little difference in BPMO was detected between sites, with values ranging from 0.75 to 2.68 U.A.F./mg prot/h. On the other hand larger differences between sites were found for reductase activities. Esterases (AChE), porphyrins (Copro-, Uro-, Proto-porphyrins) vitellogenin and zona radiata proteins were also detectable in this zooplanctonic species. Hg showed mean levels of 0.141 ppm d.w., Cd 0.119 ppm d.w. and Pb 0.496 ppm d.w. Total PAHs ranged from 860.7 to 5,037.9 ng/g d.w., carcinogenic PAHs from 40.3 to 141.7 ng/g d.w., HCB from 3.5 to 11.6 ng/g d.w., DDTs from 45.3 to 163.2 ng/g d.w. and the PCBs from 84.6 to 210.2 ng/g d.w.

Animals↗

PubMedDate not supplied

Phenotyping of beluga whale blood lymphocytes using monoclonal antibodies.

Widespread efforts are currently made to classify morphologically indistinguishable lymphocyte subpopulations in several species. In order to increase the knowledge in cetacean immunology, cross-reactivity of antibodies against bovine, human, ovine and mouse cell surface proteins was tested on beluga whale (Delphinapterus leucas) peripheral blood lymphocytes using flow cytometry. Anti-MHC class I and II as well as anti-CD2 reacted with virtually all peripheral blood lymphocytes. Anti-TCR gamma delta and anti-CD4 reacted with respectively 31% and 30% of peripheral blood lymphocytes. B lymphocytes were identified by an anti-surface IgM which was present on 6% of blood lymphocytes. Specificity of these antibodies was demonstrated by immunoprecipitation of beluga proteins with similar molecular weight to that of other species. These results could be useful for further immunotoxicological evaluation of highly versus mildly contaminated populations of belugas.

Animals↗

PubMed2000

Immunosuppression in mice fed on diets containing beluga whale blubber from the St Lawrence estuary and the Arctic populations.

In order to assess the immunotoxic potential of naturally relevant mixtures of PCBs and other organohalogens, C57Bl/6 mice were fed on diets in which lipids were replaced by blubber of beluga whales from the highly contaminated population of the Saint-Lawrence River, and the less contaminated population from the Arctic. Different ratios of blubber from both sources were mixed in order to allow a dose-response study. Mice were fed for a period of 90 days at the end of which their immunological status was monitored. For general parameters such as body weight, weight of the spleen and the thymus no significant effect of diets were observed. The immunological endpoints such as the blastic transformation of splenocytes and the spleen NK cell activity were not significantly affected by any of the diets compared to control diets. While the different cell subpopulations of peripheral blood and thymus were not affected by the diets, a significant decrease was noted in the CD8+ T cell population in the spleen of mice fed with most of the diets containing beluga blubber. Moreover, the ability of splenic cells to elicit humoral response against sheep red blood cells as well as the potential of peritoneal macrophages to perform phagocytosis were suppressed by all diets containing beluga blubbers. In summary, there was no differences between the groups fed with a blubber diet with low and high organochlorine contamination. However, a clear immunosuppression was demonstrated when these groups were compared to the group fed with beef oil. Despite the fact that we cannot exclude a possible contribution of the fatty acid composition of the beluga blubber to the immunosupression, these results suggest the sensitivity of mouse immune system towards organohalogens, and point out the toxic potential of contaminant mixtures as found in the less contaminated Arctic population.

Adipose Tissue↗

PubMed2002

Probing substates in sperm whale myoglobin using high-pressure crystallography.

Pressures in the 100 MPa range are known to have an enormous number of effects on the action of proteins, but straightforward means for determining the structural basis of these effects have been lacking. Here, crystallography has been used to probe effects of pressure on sperm whale myoglobin structure. A comparison of pressure effects with those seen at low pH suggests that structural changes under pressure are interpretable as a shift in the populations of conformational substates. Furthermore, a novel high-pressure protein crystal-cooling method has been used to show low-temperature metastability, providing an alternative to room temperature, beryllium pressure cell-based techniques. The change in protein structure due to pressure is not purely compressive and involves conformational changes important to protein activity. Correlation with low-pH structures suggests observed structural changes are associated with global conformational substates. Methods developed here open up a direct avenue for exploration of the effects of pressure on proteins.

Animals↗

PubMed2003

Fast purification of the Apo form and of a non-binding heme mutant of recombinant sperm whale myoglobin.

As molecular biology has developed it has become possible to abundantly produce heterologous proteins in bacteria and to design serial amino acid substitutions for the generation of modified proteins, an approach also known as protein engineering. Sperm whale myoglobin, a protein of broad interest, has been cloned for several years now and a large collection of mutants has been produced. The presence of heme stabilizes the protein, which is recovered soluble from the bacterial pellet, and most purification protocols take advantage of this property for myoglobin purification directly from the pellet. However, recovery from the column resin is poor with these methods making them expensive and the procedure for removing heme is laborious and drastic when the apo form of Mb is required. In the case of proteins with severe mutations, which bind heme weakly or do not bind it at all, such methods cannot be employed without massive loss of productivity. Here, we describe a modified method, which is both low cost and rapid, for the purification of the soluble apo form of Mb from Escherichia coli inclusion bodies. Biophysical characterization of the protein after purification shows that the purified apoMb retains its native conformation and is soluble. This modified method is also used for the purification of a non-heme-binding apoMb mutant, demonstrating its efficiency when dealing with drastic mutations.

Amino Acid Sequence↗

PubMed2002

Structural characterization of non-native states of sperm whale myoglobin in aqueous ethanol or 2,2,2-trifluoroethanol media.

The effects of aqueous ethanol or 2,2,2-trifluoroethanol media on the structure of sperm whale myoglobin have been investigated by absorption, CD, and NMR spectra. The structural properties of myoglobin such as heme environments, helix contents, protein folding, and interactions between heme and the protein moiety have been sharply manifested in these spectra. The characterization demonstrated that alcohol-induced conformational change of myoglobin depends on the nature of alcohol and its concentration. It was shown for the first time that, upon the alcohol-induced denaturation of myoglobin, heme is released from partially denatured protein of which helix contents is altered by only about 20% relative to that of native state. Myoglobin has shown to unfold and refold reversibly by controlling the alcohol concentration. Novel methods for the preparation of apomyoglobin and in situ reconstitution of apomyoglobin with heme, based on the alcohol-induced denaturation of the protein, were presented.

Animals↗