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PubMed1998

A SINE species from hippopotamus and its distribution among animal species.

Thirty sequences of a short interspersed repetitive element (SINE) were isolated from genomic DNA of Hippopotamus amphibius (hippopotamus). RNA polymerase III split promoter sequence was observed in all of the 30 sequences; and poly(A)-like structure at 3'-end, as well as direct repeat flanking to the repetitive sequence in many of the 30 sequences. A comparison of the consensus sequence of the 30 sequences with sequences in a DNA database (DDBJ/GENBANK/EMBL) revealed 93% homology to the consensus sequence of a whale SINE, CHR-2, and 73% homology to mouse glutamic acid tRNA. Phylogenetic analysis of tRNA-related regions of the sequences with all of the mouse tRNAs revealed that glutamic acid tRNA was genetically closest to the hippopotamus SINE. In addition, the tRNA-related region of the consensus sequence was folded into a cloverleaf structure as with mouse glutamic acid tRNA. These findings led us to conclude that the SINE of hippopotamus was genetically related to a whale SINE, CHR-2 [the hippopotamus SINE was named CHR-2(hippo)] and was a retroposon derived from glutamic acid tRNA. Hipo53 and hipo95, which were the genetically most separated CHR-2(hippo) sequences in the present study, were used as a probe for dot-blot hybridization to examine the distribution of their homologous sequences among animal species. Although the distribution spectra of hipo53 and hipo95 homologous sequences in animal species differed to some extent, large amounts of both sequences were found in Hippopotamus amphibius and Globicephala macrorhynchus (whale); and small amounts in most of the animal species in Artiodactyla examined. These findings indicated that the hippopotamus and whale had more recently branched off from the clade that includes chevrotain and pecorans than the other animal species in the clade. The 30 CHR-2(hippo) sequences were aligned, and the substitution rates among the sequences were calculated with a different substitution rate model for transition and for transversion. The calculation combined with the mutation rate of the pseudogenes (r = 4.6 x 10(9)) indicated that CHR-2(hippo) sequences diversified at least 132 million years ago (Myr).

Animals↗
PubMed1985

The acid-alkaline transition of a sea turtle myoglobin: coexistence at high pH of high- and low-spin forms.

The microenvironment of the iron in a sea turtle Dermochelys coriacea myoglobin is studied using the spectroscopic techniques EPR and optical absorption. Optical absorption spectra in the visible region suggest a great homology between turtle Mb and other myoglobins, such as those from whale, human and elephant. The pK of the acid-alkaline transition is 8.4 slightly lower than the pK of whale and equal to that of elephant myoglobin. The EPR spectrum at pH 7.0 is characteristic of a high-spin configuration with axial symmetry (gx = gy = 5.95). At higher pH, this signal changes in a way different from that observed for whale myoglobin. We observe for turtle Mb both the formation of a low-spin configuration with rhombic symmetry (gx = 2.56, gy = 2.20, gz = 1.90) and of a high-spin species with rhombic distortion (gx = 6.79, gy = 5.18, gz = 2.12). This suggests a lowering of symmetry at the haem, so that now the x and y directions are no more equivalent. This can be explained by amino acid substitution at the distal positions of haem or to off-axial positioning of distal residues. The coexistence at high pH (pH 11.0) of these two spin forms could be explained by the existence of two protein conformations, in which the crystal field splitting factor, delta, and the electron exchange energy are of the same order, allowing the presence of different configurations simultaneously. The presence of different kinds of haem is ruled out by the experiments with nitrosyl turtle Mb and turtle Mb-F showing spectra very similar to those of whale myoglobin. The pk of the acid-alkaline transition, 8.5, obtained from EPR spectra, agrees very well with results from optical absorption.

Animals↗
PubMed2006

Increased blood interleukin-10 mRNA levels in diseased free-ranging harbor porpoises (Phocoena phocoena).

Harbor porpoises from the North and Baltic Seas exhibit a higher incidence of bacterial infections compared to whales from less polluted arctic waters. Toxicological analysis revealed an association between elevated body burdens of environmental contaminants, such as polychlorinated biphenyls (PCB) and polybrominated diphenyl ether (PBDE) and lymphoid depletion in thymus and spleen of these whales. However, it remains undetermined if changes in the immune system are primarily contaminant-induced or a sequel of infectious diseases and emaciation. The aim of the present study was to investigate changes of blood cytokine mRNA levels in healthy and diseased harbor porpoises. Therefore, 29 by-caught and stranded whales were necropsied and the health status was evaluated based upon main pathological findings. Furthermore, the degree of thymic atrophy and splenic depletion was histologically graded using a semi-quantitative scoring system. Gene expression of interleukin (IL)-2, IL-4, IL-6, IL-10, transforming growth factor-beta and tumor necrosis factor-alpha in the blood was measured by real time reverse transcription-polymerase chain reaction. Thymic atrophy and splenic depletion were correlated with an impairment of the animals' health status. Additionally, a marked up-regulation of IL-10 was predominately found in severely diseased whales with evidence of chronic bacterial infections. Furthermore, increased IL-10 levels were associated with splenic depletion. Other investigated cytokines were not significantly associated with the health status or lymphoid depletion, respectively. The present study indicated that lymphoid depletion represents a sequel of chronic infectious diseases in a portion of investigated harbor porpoises. Regarding this, expression of anti-inflammatory cytokines, such as IL-10 might represent a consequence of continuous stimulation of the immune system and induction of immunomodulatory mechanisms in this cetacean species.

Animals↗
PubMed1990

High-resolution study of the three-dimensional structure of horse heart metmyoglobin.

The three-dimensional structure of horse heart metmyoglobin has been refined to a final R-factor of 15.5% for all observed data in the 6.0 to 1.9 A resolution range. The final model consists of 1242 non-hydrogen protein atoms, 154 water molecules and one sulfate ion. This structure has nearly ideal bonding and bond angle geometry. A Luzzati plot of the variation in R-factor with resolution yields an estimated mean co-ordinate error of 0.18 A. An extensive analysis of the pattern of hydrogen bonds formed in horse heart metmyoglobin has been completed. Over 80% of the polypeptide chain is involved in eight helical segments, of which seven are composed mainly of alpha-helical (3.6(13))-type hydrogen bonds; the remaining helix is composed entirely of 3(10) hydrogen bonds. Altogether, of 102 hydrogen bonds between main-chain atoms only six are not involved in helical structures, and four of these six occur within beta-turns. The majority of water molecules in horse heart metmyoglobin are found in solvent networks that range in size from two to 35 members. The size of water molecule networks can be rationalized on the basis of three factors: the number of hydrogen bonds to the protein surface, the presence of charged side-chain atoms, and the ability to bridge to neighboring molecules in the crystal lattice. Bridging water networks form the dominant intermolecular interactions. The backbone conformation of horse heart metmyoglobin is very similar to sperm whale metmyoglobin, with significant differences in secondary structure occurring only near residues 119 and 120, where residues 120 to 123 in sperm whale form a distorted type I reverse turn and the horse heart protein has a type II turn at residues 119 to 122. Nearly all of the hydrogen bonds between main-chain atoms (occurring mainly in helical regions) are common to both proteins, and more than half of the hydrogen bonds involving side-chain atoms observed in horse heart are also found in sperm whale metmyoglobin. Unlike sperm whale metmyoglobin, the heme iron atom in horse heart metmyoglobin is not significantly displaced from the plane of the heme group.

Animals↗
PubMed1997

Concentrations of chlorinated hydrocarbons and trace elements in marine mammal tissues archived in the U.S. National Biomonitoring Specimen Bank.

The U.S. National Biomonitoring Specimen Bank (NBSB) provides for the long term storage of well documented and preserved specimens representing several types of environmental matrices. A major part of this inventory consists of marine mammal tissues (e.g., blubber, liver, kidney, and muscle). Within the NBSB selected specimens are periodically analyzed for chlorinated hydrocarbons and trace elements. Although only 20% of the 560 marine mammal specimens in the NBSB have been analyzed, the database is of value in evaluating the stability of analytes and sample degradation during storage, for comparing with results from samples collected in the future for long-term monitoring, and for comparing with analytical results from other laboratories on samples collected at the same time for monitoring purposes. The NBSB analytical database contains results for 37 elements, many of which are not analyzed routinely by conventional analytical techniques used in monitoring programs, and the following organic compounds: selected PCB congeners. DDT compounds, alpha- and gamma-HCH, HCB, heptachlor epoxide, oxychlordane, cis-chlordane, trans-chlordane, cis-nonachlor, trans-nonachlor, and dieldrin in 9 marine mammal species: northern fur seal (Callorhinus ursinus), ringed seal (Phoca hispida), spotted seal (P. largha), bearded seal (Erignathus barbatus), pilot whale (Globicephala melas), harbor porpoise (Phocoena phocoena), white-sided dolphin (Lagenorhynchus acutus), beluga whale (Delphinapterus leucas), and bowhead whale (Balaena mysticetus). Analyses of beluga whale blubber for toxaphene and additional chlorinated hydrocarbons are obtained through collaboration with the Department of Fisheries and Oceans Canada.

Animals↗
PubMed2005

Total mercury, methyl mercury, and selenium levels in the red meat of small cetaceans sold for human consumption in Japan.

We surveyed the total mercury (T-Hg) and methyl mercury (M-Hg) levels in red meat products (n = 160) from small cetacean species sold for human consumption in markets throughout Japan from 2000 to 2003. Genetic identification showed that the red meat products originated from nine species: false killer whale, bottlenose dolphin, short-finned pilot whale, striped dolphin, rough-toothed dolphin, Risso's dolphin, pantropical spotted dolphin, Baird's beaked whale, and Dall's porpoise. T-Hg and M-Hg concentrations in all red meat products exceeded the provisional permitted levels of T-Hg (0.4 microg/wet g) and M-Hg (0.3 microg/ wet g) in fish and shellfish set by the Japanese government, respectively. The average M-Hg level in the most contaminated species (false killer whale) was 11.5 microg/wet g, and that in the least contaminated species (Dall's porpoise) was about 1.0 microg/wet g, exceeding or equaling the Codex guideline of M-Hg in predatory fishes (1.0 microg/wet g). Contamination levels of T-Hg and M-Hg differed considerably among samples of the nine species and among individuals of a particular species. The highest M-Hg was about 26 microg/ wet g in a sample from a striped dolphin, 87-times higher than the permitted level. The consumption of only 4 g of this product would exceed the provisional tolerable weekly intake of M-Hg for someone of 60 kg body weight (1.6 microg/kg-bw/ week). Although a high correlation between T-Hg and selenium (Se) was observed in these products, the molar ratio of T-Hg to Se was substantially higher than 1. The consumption of red meat from small cetaceans, therefore, could pose a health problem for not only pregnant women but also for the general population.

Animals↗
PubMed2003

On being the right size: heart design, mitochondrial efficiency and lifespan potential.

1. From the smallest shrew or bumble-bee bat to the largest blue whale, heart size varies by over seven orders of magnitude (from 12 mg to 600 kg). This study reviews the scaling relationships between heart design, cellular bioenergetics and mitochondrial efficiencies in mammals of different body sizes. 2. The [31P]-nuclear magnetic resonance-derived [phosphocreatine]/[ATP] ratio in hearts of smaller mammals is significantly higher (2.7 +/- 0.3 for mouse; n = 22) than in larger mammals (1.6 +/- 0.3 for humans; n = 13). 3. The inverse of the free myocardial cytosolic [ADP] concentration and the cytosolic phosphorylation ratio ([ATP]/[ADP][Pi]) scales with heart size and with absolute mitochondrial and myofibrillar volumes, close to a quarter-power (from -0.22 to -0.28; r = 0.99). 4. Assuming a similar mitochondrial P/O ratio and the same maximal amount of work required to convert 1 mol NADH to 0.5 mol O2 (i.e. 212.25 kJ/mol), the higher [ATP]/[ADP][Pi] ratios or cellular driving forces (DeltaG'ATP) in hearts of smaller mammals imply greater mitochondrial efficiencies in coupling ATP production to electron transport as body size decreases. For a P/O ratio of 2.5, the mitochondrial efficiency in the heart of a shrew, mouse, human and whale is 84, 82, 71 and 65%, respectively. 5. Higher cytosolic ATP]/[ADP][Pi] ratios and DeltaG'ATP values imply that the hearts of smaller mammals operate further from equilibrium than hearts of larger mammals. 6. As a consequence of scaling relationships, a number of remarkable invariants emerge when comparing heart function from the smallest shrew to the largest whale; the total volume of blood pumped by each heart in a lifetime is approximately 200 million L/kg heart and the total number of heart beats is approximately 1.1 billion per lifetime. 7. Similarly, the metabolic potential (total O2 consumed during adult lifespan per g bodyweight) for a 2 g shrew or a 100000 kg blue whale is approximately 38 L O2 consumed or 8.5 mol ATP/g body mass per lifetime. 8. The importance of quarter-power scaling relationships linking structural, metabolic and bioenergetic design to the natural ageing process and maximum lifespan potential is discussed.

Adenosine Diphosphate↗
PubMed2001

Immunohistochemical investigation of the cross-reactivity of selected cell markers from various species for characterization of lymphatic tissues in the harbour porpoise (Phocoena phocoena).

To facilitate a detailed investigation of cetacean lymphoid organs, 13 canine-, six bovine-, one equine-, one human- and four killer whale-specific monoclonal antibodies (mAbs) directed against cell surface antigens of the haematopoietic system (including CD2, CD4, CD8, CD45R, MHC class II, granulocyte, thrombocyte, pan-T cell and B-cell antigen), as well as a mAb and a polyclonal antibody (pAb) directed against the -peptide of the human CD3 complex, were tested for immunohistochemical cross-reactivity on frozen or formalin-fixed, paraffin wax-embedded lymphatic tissues of harbour porpoises. Eight of 26 mAbs and the pAb showed a specific reaction with harbour porpoise cells. Lymphocytes in T-cell compartments were labelled by the mAb and the pAb directed against the CD3 complex and by two killer whale mAbs specific for CD2 antigen. CD45R, labelled by a killer whale-specific mAb, was strongly expressed on B and weakly on T cells. MHC class II antigen, recognized by killer whale- and bovine-specific mAbs, was expressed on B and T cells. A canine MHC class II-specific mAb recognized an epitope on the surface of antigen-presenting cells and B lymphocytes. An anti-equine-pan-leucocyte marker labelled the majority of cells in B- and T-cell compartments. Thus, with leucocyte antigen markers from various species, it is now possible to determine the phenotype of lymphocytes in normal and diseased lymphoid organs of harbour porpoises.

Animals↗
PubMed1982

A possible immunodominant epitope recognized by murine T lymphocytes immune to different myoglobins.

We find that a single region on the surface of different species of myoglobin appears to be immunodominant for T lymphocytes, even though the residues in that region vary sufficiently that the T cells immune to one myoglobin do not crossreact with other myoglobins bearing substitutions at that site. Immunization of B10.S mice with sperm whale myoglobin elicits T-lymphocyte populations capable of recognizing sperm whale myoglobin but not horse myoglobin, whereas the converse is true when these mice are immunized with horse myoglobin. Using a series of myoglobin variants, we tested the effect of changes in primary sequence on the T-lymphocyte proliferative response. We were able to divide the myoglobin variants into two groups, depending on whether they cross stimulate sperm whale immune or horse immune T lymphocytes. The patterns of cross stimulation of both populations of myoglobin immune T lymphocytes were explained by amino acid substitutions at position 109. However, because sperm whale and horse myoglobin differ at this residue (glutamate vs. aspartate, respectively), T lymphocytes immune to each myoglobin do not crossreact with the other myoglobin. Additional data suggest that this immunodominant epitope also includes other residues nearby on the surface of the native molecule. Mixing experiments showed that the specificity was that of T lymphocytes and not antigen-presenting cells. Monoclonal anti-I-A blocking studies showed that both myoglobins are presented in association with the same Ia antigen. Possible explanations for the apparent immunodominance of this antigenic epitope, consisting of residue 109 and nearby residues on the surface of both myoglobins, include a peculiar immunogenicity of the surface topography of this site of a preferred orientation of the molecule imposed by antigen-presenting cells when T cells first encounter the antigen. The latter explanation is related to but distinct from "determinant selection." T-cell recognition of conformation is discussed.

Amino Acid Sequence↗
PubMed2000

The stabilities of mammalian apomyoglobins vary over a 600-fold range and can be enhanced by comparative mutagenesis.

Apomyoglobins from 13 different mammals were examined for resistance to denaturation by guanidinium chloride. Unfolding was followed by circular dichroism and tryptophan fluorescence and analyzed globally using the two-step, three-state mechanism first described by Barrick and Baldwin (Barrick, D., and Baldwin, R. L. (1993) Biochemistry 32, 3790-3796). With one exception, the rise and fall of Trp fluorescence intensity correlates quantitatively with the native to intermediate to unfolded steps seen in the CD curves. Although the O(2) binding properties of the holoproteins are nearly identical, the unfolding transitions of the apomyoglobins show 600-fold differences in resistance to guanidinium chloride denaturation. Apomyoglobins from diving mammals, particularly from sperm whales, are the most stable, whereas the apoproteins from pig, horse, and sheep are the least stable, indicating selective pressure for resistance to denaturation in the whale proteins. Sequence comparisons suggest that the key stabilizing residues in whale globins are Ala(5), His(12), Ile(28), Thr(51), Ala(53), Ala(74), Lys(87), Lys(140), and Ile(142). Combinations of these residues were substituted into pig myoglobin. The resultant multiple mutants showed stabilities approaching that of recombinant sperm whale apomyoglobin. Thus, comparative mutagenesis can be used to increase heme protein stability and improve expression yields in bacteria without compromising function.

Amino Acid Sequence↗
PubMed1995

The use of a shotgun for euthanasia of stranded cetaceans.

A 12-gauge shotgun, loaded with either a solid 28 g lead slug or buckshot consisting of nine individual lead pellets with a total mass of 28 g, was used to shoot the heads of one dead common dolphin (Delphinus delphis) and five dead long-finned pilot whales (Globicephala melaena) varying in length from 2.5 m to 5 m. The dolphin and the smallest pilot whale were shot with both projectiles from the dorsal surface of the head. The projectiles penetrated the head and dorsal surface of the skull, but not the base of the cranium. This site using buckshot was not effective in the larger animals. Two whales between 3 and 4 m in length were shot with buckshot through the lateral side of the head caudal to and above the eye, without penetration of the contralateral side of the head. It is concluded that shooting smaller cetaceans with a shotgun can be effective and safe. Further work is required to develop more suitable projectiles for cetaceans up to the size of mature pilot whales.

Journal Article↗
PubMed2006

Identification and characterization of a tandem repeat in exon III of the dopamine receptor D4 (DRD4) gene in cetaceans.

A large number of mammalian species harbor a tandem repeat in exon III of the gene encoding dopamine receptor D4 (DRD4), a receptor associated with cognitive functions. In this study, a DRD4 gene exon III tandem repeat from the order Cetacea was identified and characterized. Included in our study were samples from 10 white-beaked dolphins (Lagenorhynchus albirostris), 10 harbor porpoises (Phocoena phocoena), eight sperm whales (Physeter macrocephalus), and five minke whales (Balaenoptera acutorostrata). Using enzymatic amplification followed by sequencing of amplified fragments, a tandem repeat composed of 18-bp basic units was detected in all of these species. The tandem repeats in white-beaked dolphin and harbor porpoise were both monomorphic and consisted of 11 and 12 basic units, respectively. In contrast, the sperm whale harbored a polymorphic tandem repeat with size variants composed of three, four, and five basic units. Also the tandem repeat in minke whale was polymorphic; size variants composed of 6 or 11 basic units were found in this species. The consensus sequences of the basic units were identical in the closely related white-beaked dolphin and harbor porpoise, and these sequences differed by a maximum of two changes when compared to the remaining species. There was a high degree of similarity between the cetacean basic unit consensus sequences and those from members of the horse family and domestic cow, which also harbor a tandem repeat composed of 18-bp basic units in exon III of their DRD4 gene. Consequently, the 18-bp tandem repeat appears to have originated prior to the differentiation of hoofed mammals into odd-toed and even-toed ungulates. The composition of the tandem repeat in cetaceans differed markedly from that in primates, which is composed of 48-bp repeat basic units.

Animals↗
PubMedDate not supplied

Comparison of free amino acids in aqueous humor of farmed and wild salmon and of six species additionally.

OBJECTIVE: A comparative study was performed in order to identify aqueous humor amino acids possibly involved in cataract formation in farmed Atlantic salmon. METHODS: Aqueous humor amino acids from farmed salmons with and without cataract were compared with levels in wild salmon and other animals of different evolutionary levels such as frog, crocodile, turkey, goose, minke whale, and cattle. Serum samples from wild and farmed salmon and minke whale were also analyzed. RESULTS: The total amino acid concentration was lower in aqueous humor obtained from salmon, frog and crocodile compared to birds and mammals. Wild salmon had a higher content of amino acids than farmed salmon. Asparagine was absent in salmon aqueous humor and serum. Aqueous humor proline was readily detectable in wild salmon, birds, whale, and cattle, but not detectable in farmed salmon, frog and crocodile. The aqueous humor concentration of taurine was about seven- and fifty-fold lower compared to serum in wild and farmed salmon, respectively. The corresponding ratio in minke whale was 1:2. CONCLUSIONS: The results indicate a blood- aqueous barrier for taurine in farmed salmon. The lower total amino acid concentration and low aqueous humor proline concentration in farmed salmon should be further investigated.

Amino Acids↗
PubMed1977

Morphogenesis and morphology of the brain stem nuclei of Cetacea. I. The hypoglossal nucleus.

1. The hypoglossal nucleus of whalebone whales is composed of four major subdivisions, forming four parallel columns, here called the dorsomedial, the dorsolateral, the ventromedial and the ventrolateral XII columns. 2. The ventromedial XII column extends throughout the hypoglossal nucleus, forming in whalebone whales the rostral as well as the caudal end of the nucleus. 3. The ventrolateral XII column is lamelliformed and splits into a dorsomedial and a ventrolateral part, the former intimately related topographically to the dorsomedial column. 4. The dorsomedial XII column is torpedo-shaped, tapering in rostral direction and terminating a little short of the rostral end of the ventromedial XII column, while the blunt end terminates immediately caudal to the obex. 5. The dorsolateral XII column is the shortest subdivision, approximately one fourth of the length of the entire hypoglossal nucleus. The blunt rostral end of the torpedo-shaped column blends with the dorsomedial XII column, its tapering caudal end terminating rostral to the obex. 6. The cells of the hypoglossal nucleus vary in size from small to medium-sized and large, the small ones dominating in the dorsomedial, the large ones in the dorsolateral and ventromedial XII columns. The ventrolateral column is characterized by spindle-shaped cells. 7. In the toothed whale Phocaena communis the differentiation of the hypoglossal nucleus is less clearcut than in whalebone whales, but a similar structural priniciple is recognizable.

Animals↗
PubMed1993

Inhibition of protein radical reactions of ferrylmyoglobin by the water-soluble analog of vitamin E, Trolox C.

The reactivity of Trolox C, a water-soluble analog of vitamin E, toward protein radicals formed during the oxidation of metmyoglobin and the therefrom derived molecular products was examined in terms of the ability of the phenolic antioxidant to prevent specific oxidative reactions involving tyrosyl radicals and to reduce the molecular products to functional hemoproteins. (i) Trolox prevented the oxidative reactions initiated upon oxidation of the hemoprotein by H2O2 and involving tyrosyl radicals: on one hand, it inhibited the covalent binding of protein to the heme group and, on the other hand, it inhibited dimerization of sperm whale myoglobin, the latter process entailing the intermolecular covalent binding of tyrosines. The inhibition of both processes required concentrations of Trolox 20- to 50-fold higher than those needed to reduce the hypervalent heme iron to its ferric form. Likewise, Trolox inhibited dimerization and polymerization of sperm whale myoglobin upon its treatment with chloroiridate, a process associated with formation of tyrosyl radicals and negligible oxidation of the heme iron. However, these results did not provide unambiguous evidence for the reactivity of the phenolic antioxidant toward amino acid radicals in myoglobin, for Trolox displayed a high reactivity toward the oxidant, chloroiridate. (ii) The stable oxidation product originating from sperm whale myoglobin oxidation, i.e., the dimeric hemoprotein, was redox active, inasmuch as it retained its capacity to form an oxy complex upon reduction and an oxoferryl complex upon oxidation by H2O2. The latter complex was reduced by Trolox to a compound which exhibited a 10- to 12-nm blue shift of the 632-nm absorption typical of the native metmyoglobin. Although this absorption shift was likely to express oxidative modifications of the porphyrin ring, the modified hemoprotein retained its capacity to react with peroxides and displayed a peroxidative activity.

Animals↗
PubMed1995

Relation of a seafood diet to mercury, selenium, arsenic, and polychlorinated biphenyl and other organochlorine concentrations in human milk.

Human transition milk was sampled from 88 mothers at the Faroe Islands, where the seafood diet includes pilot whale meat and blubber. Milk mercury concentrations (median, 2.45 micrograms/liter) were significantly associated with mercury concentrations in cord blood and with the frequency of pilot whale dinners during pregnancy. Milk selenium concentrations (mean, 19.1 micrograms/liter) correlated significantly with concentrations in cord blood but not with seafood consumption. Arsenic concentrations were very low. Twenty-four of the milk samples were separated into four pools based on fish intake and milk mercury concentrations. The polychlorinated biphenyl (PCB) concentrations (1.8-3.5 micrograms/g lipid) were high and mainly due to congener numbers 153, 180, and 138. One pool contained a congener 77 concentration of 1380 ppt, which is the highest ever reported in a human specimen for a coplanar PCB. The highest PCB concentrations were seen in the pools from women who had eaten frequent whale dinners and whose milk contained high mercury concentrations. The concentrations of chlorinated dibenzo-p-dioxins and furans were not similarly elevated. Given the advantages associated with breast-feeding, advice to nursing mothers in this population should take into regard the possible risks associated with long-term exposure to milk contaminants.

Adult↗
PubMed1978

Acid Bohr effects in myoglobin characterized by proton NMR hyperfine shifts and oxygen binding studies.

Proton NMR studies of sperm whale and horse deoxymyoglobin have revealed that both proteins exhibit a single, well defined, pH-induced structural change. The changes in hyperfine shifts are clearly observed not only at the heme peripheral substituents, but also at the proximal histidyl imidazole, which suggest that heme-apoprotein contacts are looser in the acidic than alkaline conformations. The hyperfine shift changes are modulated by a single titratable group with a pK of approx. 5.7 in both proteins. Oxygen binding studies of sperm whale myoglobin over a range of temperature and pH showed that, while the oxygen affinity was independent of pH at 25 degrees C, it increased below pH 7 at 0 degrees C and decreased below pH 7 at 37 degrees C. Hence, sperm whale myoglobin exhibits a small acid Bohr effect which most likely arises from the characterized structural changes in the deoxy proteins. While horse myoglobin failed to exhibit a resolvable acid Bohr effect between 0 and 37 degrees C, it did show a weak alkaline Bohr effect at 25 degrees C which disappeared at lower temperatures. Since the oxygen affinity changed smoothly over several pH units, this alkaline Bohr effect can not be associated with any well defined conformational change detected by NMR.

Animals↗
PubMed1978

Oxygenation and EPR spectral properties of Aplysia myoglobins containing cobaltous porphyrins.

Cobalt myoglobins (Aplysia) have been reconstituted from apo-myoglobin (Aplysia) and proto-, meso-, and deutero-cobalt porphyrins. Each of them showed the 30--60 times lower oxygen affinity than those of the corresponding cobalt myoglobins (Sperm whale). Kinetic investigation of their oxygenation by the temperature-junp relaxation technique showed that the low oxygen affinity of cobalt myoglobin (Aplysia) is due to a large dissociation rate constant. the electron paramagnetic resonance (EPR) spectrum of oxy cobalt myoglobin (Aplysia) is affected by the replacement of H2O with D2O, suggesting a possible interaction between the bound oxygen and the neighboring hydrogen atom. A low temperature photodissociation study showed that the product of photolysis of oxy cobalt myoglobin (Aplysia) gives an EPR spectrum different from that of the deoxy-cobalt myoglobin (Aplysia) and from that of the photolysed form of oxy-cobalt myogloin (Sperm whale). These observations suggest that in oxy-cobalt myoglobin (Aplysia) the bound oxygen might interact with amino acid adjacent to it, but the interaction is weaker than that in oxy cobalt myoglobin (Sperm whale).

Animals↗