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PubMed1994

Digestion of herring by indigenous bacteria in the minke whale forestomach.

Northeastern Atlantic minke whales (Balaenoptera acutorostrata) have a multichambered stomach system which includes a nonglandular forestomach resembling that of ruminants. Bacteria from the forestomachs of herring-eating whales were enumerated and isolated in an anaerobic rumen-like culture medium (M8W medium). The total viable population of anaerobic bacteria ranged from 73 x 10 to 145 x 10/ml of forestomach fluid (n = 4). Lactobacillus spp. (19.7%), Streptococcus spp. (35.9%), and Ruminococcus spp. (12.8%) were the most common of the bacterial strains (n = 117) isolated by use of M8W medium from the forestomach fluid population of two minke whales. Most of the isolates stained gram positive (93.2%), 62.4% were cocci, and all strains were strictly anaerobic. The population of lipolytic bacteria in one animal, enumerated by use of a selective lipid medium, constituted 89.7% of the viable population. The total viable population of anaerobic bacteria in freshly caught and homogenized herring (Clupea harengus) ranged from 56.7 to 95.0 cells per gram of homogenized prey (n = 3) when M8W medium was used. Pediococcus spp. (30.6%) and Aerococcus spp. (25.0%) were most common of the bacterial strains (n = 72) isolated from the homogenized herring. Most of the bacterial strains were gram positive (80.6%), and 70.8% were cocci. Unlike the forestomach bacterial population, as many as 61.1% of the strains from the herring were facultatively anaerobic. All bacterial strains isolated from the prey had phenotypic patterns different from those of strains isolated from the dominant bacterial population in the forestomach, indicating that the forestomach microbiota is indigenous. Scanning electron microscopic examinations revealed large numbers of bacteria, surrounded by a glycocalyx, attached to partly digested food particles in the forestomach. These data support the hypothesis that symbiotic microbial digestion occurs in the forestomach and that the bacteria are indigenous to minke whales.

Journal Article↗

PubMed1997

Evidence for the microbial basis of a chemoautotrophic invertebrate community at a whale fall on the deep seafloor: bone-colonizing bacteria and invertebrate endosymbionts.

To explore the microbial basis for a remarkable macrofaunal community at the site of a whale skeleton on the seafloor of the Santa Catalina Basin, we obtained samples of whale bone, bone-colonizing invertebrates, microbial mats, and the dominant fauna in the adjacent sulfide-rich sediments during Alvin expeditions in 1988 and 1991. Invertebrate tissues were examined by transmission electron microscopy (TEM) and mats and bone-penetrating bacteria by epifluorescence microscopy (EM). Tissues from the dominant bivalve Vesicomya c.f. gigas, the mytilid mussel Idasola washingtonia, and selected gastropods and limpets were also assayed chemically for enzymes diagnostic of sulfur- and methane-based chemoautotrophy and for stable carbon isotopic composition. Results of all analyses were consistent with dominant sulfur-based endosymbioses in the clam and mussel (the first record of endosymbiosis in the genus Idasola) and the general absence of methane symbioses at the site, strengthening the analogy of the whale-skeleton faunal community to those known from distant Pacific hydrothermal vent sites. Examples of minor endosymbionts, either nitrifying or methanotrophic cells according to internal membrane structures by TEM, raised the possibility of a supplemental mode of nutrition to the clam, or means to remove ammonia in the gill tissue, in the event of significant changes in the chemical environment.

Animals↗

PubMed1997

The arterial system of the sperm whale (Physeter macrocephalus).

The angioarchitecture of the sperm whale is basically similar to that of other mammals, but it has specific attributes associated with the aquatic environment of this animal and its tolerance for deep and long diving. Specialized features include an expansive aortic arch, unusually far anterior localization of the arch, symmetrical branching of common carotid and subclavian arteries from the aorta, the absence of direct connection between internal carotid arteries and brain arteries, the absence of a costocervical artery, and the presence of a well-developed occipital artery. The sperm whale has extraordinarily well-developed retia mirabilia, distributed in the cranial cavity, vertebral canal, neck and thoracic cavity, around the optic nerve, and in the walls of the uterus. These retia are more extensively developed in the sperm whale than in any other cetacean previously studied.

Animal Structures↗

PubMed1984

Anatomy and vasculature of a minke whale heart.

The heart from a 4-m-long minke whale (Balaenoptera acutorostrata) was studied to determine the details of its anatomy and to consider cardiac adaptations to diving. The volume fraction (Vvc) of capillaries in the wall of the left ventricle was determined at different levels from base to apex and at different depths from epi- to endocardium using a light microscopic stereologic technique. Typical of cetaceans, this minke whale heart was distinctly flattened dorsoventrally. A moderator band, characteristic of ungulate hearts, spanned the right ventricle. The right and left atrioventricular valves were tricuspid and bicuspid, respectively. The right coronary artery supplied the dorsal and right lateral myocardium. The left coronary artery supplied the ventral and left lateral myocardium. An anastomosis between the dorsal and ventral interventricular arteries occurred in the dorsal interventricular groove. Stereologically, a decreasing transmural gradient in Vvc was identified between the epicardium and the subepicardium at 15 cm from the apex. Our results, however, did not reveal any significant deviations in the pattern of capillary distribution in the wall of the left ventricle between this baleen whale and terrestrial mammals. Measurements of the heart, great vessels, coronary vasculature, and ventricular walls are also given, and they suggest a physiologic and adaptive right ventricular hypertrophy. Based on these and other observations, we propose that the relatively great thickness of the right ventricle and the distinctive shape of the cetacean heart are adaptations to the hemodynamic changes and collapse of the thorax associated with apneic diving.

Animals↗

PubMed2002

Description of a poorly differentiated carcinoma within the brainstem of a white whale (Delphinapterus leucas) from magnetic resonance images and histological analysis.

In this study we used magnetic resonance imaging (MRI) to investigate neuroanatomical structure in the brain of a white whale (Delphinapterus leucas) that died from a large tumor within the brainstem. This specimen was also compared with a normal white whale brain using MRI. MRI scans of the white whale specimen show how the tumor deformed surrounding brain structure. Histopathological analysis indicated a poorly differentiated carcinoma of uncertain origin. These analyses demonstrate the usefulness of supplementing histological analyses of pathology with studies of gross morphology facilitated by MRI.

Animals↗

PubMed1985

Epidermal and papillary dermal characteristics of the bowhead whale (Balaena mysticetus).

Skin samples from most body regions of the bowhead whale were examined. The epidermis is 2.7 to 50 times thicker than that reported in other cetaceans with both regional and individual variations in thickness. The thinnest areas examined (1 mm) occur on the eyelid margins and the thickest (25 mm) occur on the lower jaw. A distinctive parakeratotic stratum corneum with a thick underlying stratum spinosum (without a stratum granulosum) extends over the entire body surface. From a few dozen to several hundred epidermal lesions are present on all whales studied. A typical stratum basale of germinative keratinocytes (with melanocytes in pigmented areas) rests upon a well-defined basal lamina. Epidermal rod arrays arise from the basal keratinocytes which cover highly elongated dermal papillae and extend to the epidermal surface through the distal stratum spinosum and the stratum corneum. At least four diatom genera occur on and in the stratum corneum and lesion areas of different whales. The superficial dermis consists of a papillary layer with long (up to 13 mm) dermal papillae interdigitating with the epidermis from a basal area that is 2-4 mm in thickness. The number of dermal papillae per mm2 varies inversely with the thickness of the epidermis. Large diameter, sensory papillae packed with tortuous, highly elongated, encapsulated nerve end organs also interdigitate with the thin epidermal areas of the ventral surface of the rostrum, the upper and lower lip margins, and the upper and lower eyelid margins. Scattered, single, stiff hairs emerge from the skin only in specific, pigmented regions of the head.

Animals↗

PubMed1999

Analysis of the binding of the Fab fragment of monoclonal antibody NC10 to influenza virus N9 neuraminidase from tern and whale using the BIAcore biosensor: effect of immobilization level and flow rate on kinetic analysis.

The binding of the Fab fragment of monoclonal antibody NC10 to influenza virus N9 neuraminidase, isolated from tern and whale, was measured using an optical biosensor. Both neuraminidases, homotetramers of 190 kDa, were immobilized to avoid multivalent binding, and the binding of the monovalent NC10 Fab to immobilized neuraminidase was analyzed using the 1:1 Langmuir binding model. A contribution of mass transport to the kinetic constants was demonstrated at higher surface densities and low flow rates, and was minimized at low ligand densities and relatively high flow rates (up to 100 microl/min). Application of a global fitting algorithm to a 1:1 binding model incorporating a correction term for mass transport indicated that mass transport was minimized under appropriate experimental conditions; analysis of binding data with a mass transport component, using this model, yielded kinetic constants similar to those obtained with the 1:1 Langmuir binding model applied to binding data where mass transport had been minimized experimentally. The binding constant for binding of NC10 Fab to N9 neuraminidase from tern influenza virus (K(A) = 6.3 +/- 1.3 x 10(7) M(-1)) was about 15-fold higher than that for the NC10 Fab binding to N9 neuraminidase from whale influenza virus (K(A) = 4.3 +/- 0.7 x 10(6) M(-1)). This difference in binding affinity was mainly attributable to a 12-fold faster dissociation rate constant of the whale neuraminidase-NC10 Fab complex and may be due to either (i) the long-range structural effects caused by mutation of two residues distant from the binding epitope or (ii) differences in carbohydrate residues, attached to Asn(200), which form part of the binding epitope on both neuraminidases to which NC10 Fab binds.

Animals↗

PubMed1996

Molecular cloning and sequencing of interleukin 6 cDNA fragments from the harbor seal (Phoca vitulina), killer whale (Orcinus orca), and Southern sea otter (Enhydra lutris nereis).

Using polymerase chain reaction, interleukin-6 (IL-6) cDNA fragments from harbor seal (Phoca vitulina), killer whale (Orcinus orca), and Southern sea otter (Enhydra lutris nereis) were cloned and sequenced. For all three species, a continuous open reading frame encoding 203 residues for harbor seal, 199 residues for killer whale, and 201 residues for sea otter with stop codons located at analogous positions were identified. These fragments correspond to nucleotides 71 - 753 of the human IL-6 transcript and represent 96% of the complete coding nucleotides. Comparison of these marine mammal sequences with other published mammalian IL-6 cDNA demonstrated that both harbor seal and sea otter IL-6 had most similarity to that of other terrestrial carnivores (Mustelidae and Canidae), while killer whale had highest identity with ruminants (Bovidae and Ovidae). Among the three marine mammal species characterized, as well as cDNA sequences from nine other species, 40 invariant amino acids, including a number of residues situated at the putative gp80 and gp130 receptor binding sites, were identified. The presence of invariant amino acids within the receptor-binding portion of IL-6 for twelve different species suggests these positions are essential for biological activity of IL-6 and, moreover, likely account for the cross-reactivity among different mammalian IL-6-like activities in mouse bioassays. An additional significant finding was the presence of several variant residues only within the mouse putative IL-6 receptor binding region, which may account for observations of restricted cross-reactivity of mouse IL-6-like activity in human bioassays. Together, these findings provide insights into the evolution of the mammalian IL-6 gene and additional valuable information regarding amino acid residues essential for the biological activity of mammalian IL-6.

Amino Acid Sequence↗

PubMed1999

Evaluating a putative bottleneck in a population of bowhead whales from patterns of microsatellite diversity and genetic disequilibria.

A size-selected Balaena mysticetus genomic library was screened for clones containing simple sequence repeat, or microsatellite, loci. A total of 11 novel loci was identified. These loci were combined with a set of 9 published loci, for a total of 20 markers, and were scored across a sample of 108 bowhead whales from the Bering-Chukchi-Beaufort Seas population of bowhead whales. Genetic variability was measured in terms of polymorphism information content values and unbiased heterozygosity. From the latter, estimates of long-term effective population size were obtained. In addition, gametic phase disequilibrium among loci was investigated. Moderate to high levels of polymorphism were found overall, and the long-term effective size estimates were large relative to total population size. Tests of heterozygosity excess (Cornuet and Luikart 1996) and allele frequency distribution (Luikart et al. 1998) indicated that the possibility of a recent genetic bottleneck in the Bering-Chukchi-Beaufort Seas population of bowhead whales is highly unlikely. However, the fact that five loci displayed a statistically significant heterozygote deficiency remains to be explained.

Animals↗

PubMed2003

Locomotor behaviours and respiratory pattern of the Mediterranean fin whale (Balaenoptera physalus).

Twenty-four Mediterranean fin whales were tracked in open sea with a method based on the assessment of the animal differential position in respect of the observer's absolute position aboard a vessel, with the concomitant recording of the respiratory activity. Short distance video recording was also performed in two whales, permitting the simultaneous determination of single breath expiratory (TE) and inspiratory (TI) durations. In the 24 whales swimming at an average velocity of 1.39 (0.47) m.s(-1) [mean (SD), range: 0.62-2.44 m.s(-1)], 2068 breaths organized in 477 respiratory cycles were observed. Each cycle entailed a prolonged apnoea dive phase [225 (91) s, Tdive) followed by a period near the surface [62 (28) s, surfacing], during which a series of breaths [4.6 (1.8)] was performed at short intervals. On the basis of track length and swimming velocity, two groups of animals were devised differing for convolution of the course (p<0.001), extension of ranging territory (p<0.01) and horizontal swimming velocity (p<0.05), which may represent two distinct behaviours. A possibly general mechanism of control of breathing in cetaceans was found, consistent with a model of constant tidal volume and variable respiratory frequency. Coherently with this model, TE was independent of TI or Tdive, in line with a passive expiration, while TI appeared to be negatively correlated with Tdive (p<0.05), otherwise suggesting, similarly with terrestrial mammals, a significant role of hypercapnic stimulation. The estimated O2 consumption of about 150 l.min(-1) is in line with the general allometric regression for mammals and corresponds to an energetic expenditure of 85-95 kJ.kg(-1).day(-1).

Animals↗

PubMed1977

The myoglobin of the killer whale (Orcinus orca).

Whereas the myoglobin of the dolphin surprisingly resembles that of the sperm whale more than that of the porpoise, the myoglobin of a killer whale does not show this feature. It differs from the myoglobins of the dolphin in 6, of the porpoise in 8, and of the sperm whale in 14 positions. The residues in which the cetaceans differ are localised in one particular area of the molecule.

Amino Acid Sequence↗

PubMed1995

Immune functions in beluga whales (Delphinapterus leucas): evaluation of phagocytosis and respiratory burst with peripheral blood leukocytes using flow cytometry.

Flow cytometric assays using peripheral blood were developed to study phagocytosis and respiratory burst, the two major functions of neutrophils and among the most important non-specific defense mechanisms, in beluga whales. The use of flow cytometry avoids the problems associated with the isolation and purification of different cell types, and allows the measurement of a large number of cells (10,000) in a very short period of time. The methods described will be used to compare these functions in blood samples from highly contaminated beluga whales from the St. Lawrence and from relatively clean arctic beluga whales.

Animals↗

PubMed1992

Electrocardiogram of the humpback whale (Megaptera novaeangliae), with specific reference to atrioventricular transmission and ventricular excitation.

OBJECTIVES: The objective of the study was to record the electrocardiogram (ECG) of a large whale to obtain crucial data for comparative electrophysiologic analysis. BACKGROUND: The data were needed to establish the mismatch between heart size and PR interval and QRS duration in mammals. METHODS: In the waters off the coast of Newfoundland, in two humpback whales (Megaptera novaeangliae) with an estimated weight of 30,000 kg a 1-lead ECG was recorded, enabling reliable assessment of P waves and QRS complexes. RESULTS: It was found that both the PR interval (atrioventricular [AV] transmission time) and QRS duration (ventricular excitation) are extremely short for animals of this size. These findings are difficult, if not impossible, to explain on the basis of currently accepted electrophysiologic theories. However, the narrow QRS complex may be due to a very dense His-Purkinje network in the ventricular wall of whales. Alternative mechanisms that can explain the function of the mammalian AV node need to be considered and explored. CONCLUSIONS: The results of the study may be of value for the understanding of the ECG in humans.

Animals↗

PubMed1993

Analysis of selenium metabolites in urine samples of minke whale (Balaenoptera Acutorostrata) using ion exchange chromatography.

1. To study the distribution of selenium metabolites in whale urine, an analytical methodology for separation and determination has been developed. 2. From whale urine, five selenium components, including trimethylselenonium ion were separated and determined by a combination of ion exchange chromatography and fluorometry. 3. The mean urinary selenium level of five minke whales was 1500 ng/ml, with a standard deviation of 400 ng/ml, i.e., about 30 times as high as that for humans.

Animals↗

PubMed1992

Reduction of sperm whale ferrylmyoglobin by endogenous reducing agents: potential reducible loci of ferrylmyoglobin.

The reactivity of the endogenous antioxidants ascorbate, ergothioneine, and urate toward the high oxidation state of sperm whale myoglobin, ferrylmyoglobin-formed upon oxidation of metmyoglobin by H2O2--was evaluated by optical spectroscopy and SDS-PAGE analysis. Depending on whether these antioxidants were present in the reaction mixture before or after the addition of H2O2 to a metmyoglobin suspension, two different effects were observed: (a) In the former instances, ascorbate, ergothioneine, and urate reduced efficiently the oxoferryl moiety in ferrylmyoglobin to metmyoglobin and prevented dimer formation, a process which requires intermolecular cross-link involving specific tyrosyl residues. In addition, all the reducing compounds inhibited--albeit with different efficiencies--dityorosine-dependent fluorescence build up produced via dimerization of photogenerated tyrosyl radicals. (b) In the latter instances, the antioxidants reduced the preformed sperm whale ferrylmyoglobin to a modified metmyoglobin, the spectral profile of which was characterized by a blue shift of the typical 633 nm absorbance of native metmyoglobin. In addition, under these experimental conditions, the antioxidants did not affect dimer formation, thus indicating the irreversible character of the process. The dimeric form of sperm whale myoglobin--separated from the monomeric form by gel electrophoresis of a solution in which ergothioneine was added to preformed ferrylmyoglobin--revealed optical spectral properties in the visible region identical to that of the modified myoglobin. This suggests that the dimeric form of the hemoprotein is redox active, inasmuch as the oxoferryl complex can be reduced to its ferric form. These results are discussed in terms of the potential reactivity of these endogenous antioxidants toward the reducible loci of ferrylmyoglobin, the oxoferryl moiety, and the apoprotein radical.

Animals↗

PubMed2006

Benzo[a]pyrene cytotoxicity in right whale (Eubalaena glacialis) skin, testis and lung cell lines.

The North Atlantic right whale (NARW) is one of the most endangered great whales. The NARW population consists of only about 300 individuals and is reproducing at an insufficient rate. There is growing concern about the potential effects of environmental contaminants on the reproductive and overall health of NARW. High contaminant burdens can accumulate in tissues of great whales but toxicological studies of their effects are limited due to legal, logistical and ethical restrictions and specific in vitro models are critically needed. Cell lines from NARW skin and internal organs were previously created in our laboratory. In this study, skin, testis and lung primary fibroblast cell lines were exposed to benzo[a]pyrene (BP) as part of a multi-chemical toxicity testing project in NARW. Cells were exposed for 24-72 h to 10 nM-10 microM BP dissolved in dimethylsulfoxide. Cytotoxicity was measured with a clonogenic assay using standard methods. Some cytotoxicity was observed after 24 h, the highest concentration (10 microM BP) resulting in 77, 74 and 51 percent relative survival in testis, skin and lung cells, respectively, and indicating a higher cytotoxicity in the lung (p < 0.05). After 48 and 72-h exposure, 10 microM BP resulted in 24 and 3, 74 and 27, and 42 and 23 percent relative survival in testis, skin and lung cells, respectively. Cytotoxicity significantly increased with exposure time in all three tissues (p < 0.05 for skin and p < 0.01 for lung and testis), suggesting metabolic activation of BP in the three organs. Fibroblast cytotoxicity observed in the testis was higher than that observed either in the skin or lung after 48 h (p < 0.01) and was close to 100% after 72 h, warranting further investigation of the potential effects of PAHs on reproductive health.

Animals↗

PubMed2005

Molecular cloning and mRNA expression of cytochrome P4501A1 and 1A2 in the liver of common minke whales (Balaenoptera acutorostrata).

This study presents full-length cDNA sequences of CYP1A1 and 1A2, in common minke whale (Balaenoptera acutorostrata) from the North Pacific. Both CYP1A1 and CYP1A2 cDNAs had an open reading frame of 516 amino acid residues, and predicted molecular masses were 58.3 kDa and 58.1 kDa, respectively. The deduced full-length amino acid sequence of CYP1A1 revealed higher identities with those of sheep (86%) and pig (87%), and that of CYP1A2 was most closely related to human (82%) and monkey CYP1A2 (82%) among species from which CYP1A2 has been isolated so far. Differences in certain conserved and functional amino acid residues of CYP1A1 and 1A2 between common minke whale and other mammalian species indicate the possibility of their specific metabolic function. Concentrations of organochlorine compounds (OCs) including PCBs and DDTs analyzed in common minke whale liver showed no significant correlation with hepatic mRNA expression levels of CYP1A1 and CYP1A2, indicating no induction of these enzymes by such OCs.

Amino Acid Sequence↗

PubMed2005

A review of the criteria used to assess insensibility and death in hunted whales compared to other species.

This review addresses the diagnosis of insensibility and death in various species so as to evaluate the validity of the current criteria used to judge death in hunted whales by the International Whaling Commission (IWC). The only other species in which official criteria of death have been formulated is humans and these are controversial with the kernel of the debate being the definition of brain death. In slaughter animals, the moment of insensibility is regarded as the most important criterion and the issue has received scientific interest related to the pre-slaughter stunning. During hunting of terrestrial wildlife, the moment of death is usually regarded as the moment the animal falls and does not move. Based on the data presented in the present paper, it is concluded that when death in whales is solely determined on the basis of the IWC criteria, which in practice are based on immobility, a significant proportion of animals will be recorded as being sensible and alive when they are actually unconscious and the time to death (TTD) will be overestimated. If the criteria are used in conjunction with a postmortem examination, the recorded TTD will be closer to the real TTD and can be used for comparison of methods and performance.

Animal Welfare↗