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PubMed1991

Fluorescence study of the conformational properties of myoglobin structure. 3. pH-dependent changes in porphyrin and tryptophan fluorescence of the complex of sperm whale apomyoglobin with protoporphyrin IX; the role of the porphyrin macrocycle and iron in formation of native myoglobin structure.

The porphyrin and tryptophan fluorescence of sperm whale apomyoglobin complexed with protoporphyrin IX has been studied in the pH range 2-13. It has been shown that the fluorescence and absorption spectra of protoporphyrin incorporated into the heme crevice remain constant in the pH range 5.5-10.8 but change significantly at pH less than 5.5 and pH greater than 10.8, due to the acid and alkaline denaturation, respectively, of the complex accompanied by dissociation of protoporphyrin IX. At the same pH ranges, the quantum yield of tryptophanyl fluorescence increases sharply as a result of removal of protoporphyrin, acting as a quencher, from the complex. Other parameters of tryptophanyl fluorescence (maximum position, halfwidth and spectrum shape) change in the alkaline region as well. In the acidic pH range, these parameters change only at pH less than 4.3, indicating that the Trp surroundings are more stable to denaturation than the heme crevice region. Between pH 5.5 and 10.9, where the complex of apomyoglobin with protoporphyrin IX is in its native state, the main parameters of tryptophan fluorescence remain unchanged except for the ratio I325/I350 which diminishes at pH greater than 9.5. Its alteration precedes the alkaline denaturation of the complex and can be explained by a local conformational change induced by the break of the 'salt bridges' essential for the maintenance of the native Mb structure in the N-terminal region. The fluorescence data obtained for apomyoglobin, myoglobin and the complex between protoporphyrin IX and apomyoglobin enable one to compare their structures and to evaluate the role of the porphyrin macrocycle and the iron atom in the formation of the native myoglobin structure and its functioning.

Animals↗

PubMed1991

Structural studies on sulfated oligosaccharides derived from the carbohydrate-protein linkage region of chondroitin sulfate proteoglycans of whale cartilage.

From the carbohydrate-protein linkage region of whale cartilage proteoglycans, which bear predominantly chondroitin 4-sulfate, one nonsulfated, two monosulfated and one disulfated hexasaccharide alditols were isolated after exhaustive digestions with Actinase E and chondroitinase ABC, and subsequent beta-elimination. Their structures were analyzed by chondroitinase ACII digestion in conjunction with HPLC and by 500-MHz 1H-NMR spectroscopy. The nonsulfated compound (A) had the following conventional structure: delta GlcA(beta 1-3)-GalNAc(beta 1-4)GlcA(beta 1-3)Gal(beta 1-4)Xylol, where GlcA, delta GlcA and GalNAc are glucuronic acid; 4,5-unsaturated glucuronic acid and 2-deoxy-2-N-acetylamino-D-galactose, respectively. The other compounds were sulfated derivatives of compound A. Two monosulfated compounds (B and C) had an ester sulfate on C4 or C6 of the GalNAc residue, respectively and the disulfated compound (D) had two ester sulfate groups, namely, one on C4 of the GalNAc and the other on C4 of the Gal residue substituted by GlcA. The molar ratio of A/B/C/D was 0.21:0.16:0.36:0.27. The compound containing Gal-4-O-sulfate was previously isolated by us in the form of a sulfated glycoserine [delta GlcA(beta 1-3)GalNAc(4-O- sulfate)(beta 1-4)GlcA(beta 1-3)Gal(4-O-sulfate)(beta 1-3)-Gal(beta 1- 4)Xyl beta 1-O-Ser] from the carbohydrate-protein linkage region of rat chondrosarcoma chondroitin-4-sulfate proteoglycans [Sugahara K., Yamashina, I., DeWaard, P., Van Halbeek, H. & Vliegenthart, J.F.G. (1988) J. Biol. Chem. 263, 10,168-10,174]. The discovery of this structure in the carbohydrate-protein linkage region of chondroitin 4-sulfate proteoglycans from nontumorous cartilage indicates that it is not a tumor-associated product but rather a physiological biosynthetic product since it represents a significant proportion. The biological significance of this structure is discussed in relation to glycosaminoglycan biosynthesis.

Animals↗

PubMed1997

1H-NMR study of inter-segmental hydrogen bonds in sperm whale and horse apomyoglobins.

NMR signals for HisB5 N(delta)H and HisEF5 N(epsilon)H protons of sperm whale and horse apomyoglobins were assigned and compared with the corresponding signals of the holoproteins in terms of pH and temperature dependence behaviors of their shifts and line widths in order to gain insight into structural difference between the apoproteins and the holoproteins. Since these protons are involved in internal hydrogen bonds at the interfaces between the B helix and the GH corner and between the EF corner and the H helix, local structures of the interfaces in these proteins have been inferred from the analyses of these signals. A large difference in the line width of HisEF5 N(epsilon)H proton signal between the apoproteins and the holoproteins strongly suggested that a sizable structural alteration is induced in the EF-H interface by the removal of heme. However, the results for HisB5 N(delta)H proton resonance indicated the absence of a significant structural alteration in the B-GH interface by heme extraction. These results are consistent with the data obtained from mutation [Hughson, F. M. & Baldwin, R. L. (1989) Biochemistry 28, 4415-4422] and amide-proton-exchange kinetic [Hughson, F. M., Wright, P. E. & Baldwin, R. L. (1990) Science 249, 1544-1548] studies, which indicated that the A, B, G and H helices in apomyoglobin maintain the same packing as they do in holoprotein.

Animals↗

PubMed1983

T-lymphocyte recognition of sperm-whale myoglobin. Recognition of synthetic peptides carrying antigenic site 5 by myoglobin-primed T-cells.

Previous studies from this laboratory have resulted in the determination of the antigenic structure of sperm-whale myoglobin (Mb). In the present work, we have investigated the fine specificity requirements for T-cell recognition of one of the Mb antigenic sites (antigenic site 5). The antigenic site (peptide 145-153) and seven progressively longer peptides, increasing in length stepwise by two residues at a time, up to 22 residues in length (peptide 132-153), were synthesized. In addition, four truncated peptides were synthesized with intentional deletions at Tyr-151 and Ala-144. The T-cell recognition of these purified synthetic peptides was examined here in detail in three strains of mice (BALB/cByJ, B10.D2/n and SJL/J). Mb-primed mice afforded T-cells which proliferated to smaller peptides (two or four residues longer than the site; i.e. peptides 145-153 and 143-153) and more so to the longer peptides 135-153 and 132-153 and to Mb. No response was obtained to the truncated peptides, thus underscoring the fine specificity T-cells. No response was obtained also to intermediate-sized peptides. The latter result, due to an unfavourable mode of folding, suggested a conformational dependency in T-lymphocyte recognition.

Animals↗

PubMed1992

Metabolic rates of minke whales (Balaenoptera acutorostrata) in cold water.

Body temperature, blubber thickness and lung capacity (Vc) were recorded in newly killed minke whales, while respiratory frequency (f) was determined in free-swimming animals. Mean deep (thoracic) body temperature was 34.7 +/- 0.8 (SD) degrees C (n = 14). Weighted mean core/blubber interface temperature in animals caught in 2.5-5.5 degrees C water was 28.8 +/- 1.7 degrees C (n = 8). The minimum average rate of sensible heat loss (HLs) was 3.81 +/- 0.53 (SD) W kgw-0.75 (n = 8) in animals with body masses (w) in the range of 1840 to 5740 kg, HLs being inversely proportional to w (HLs = -2.98 10(-4) w +4.89 W kgw-0.75 (n = 8, r2 = 0.73, P less than 0.01)). The average rate of respiratory heat loss (HLr) was 0.26 +/- 0.04 (SD) W kgw-0.75, regardless of w, in the same 8 animals. Total rates of heat loss (HL = HLr+HLs) in 2.5-5.5 degrees C water ranged between 3.40 and 4.87 W kgw-0.75, with an average of 4.06 +/- 0.52 (SD) W kgw-0.75 (n = 8). Estimates of oxygen consumption based on records of f and Ve, and data on oxygen extraction from other cetaceans, yielded a range of metabolic rates which compared nicely with the calculated HL values.

Adipose Tissue↗

PubMed1995

Daily energy expenditure in free living minke whales.

Six minke whales (Balaenoptera acutorostrata) were instrumented with VHF-radio transmitters and four with sonic speed-depth transmitters off the west coast of northern Norway and Svalbard and followed within view for up to 24 h. During such periods their respiratory rate was continuously recorded and their energy expenditure estimated according to Folkow & Blix (1992) at different swimming speeds and types of activity. We found that cost of swimming is remarkably low in these large animals and that their estimated daily energy expenditure on average only amounts to 80 kJ kg-1 day-1.

Animals↗

PubMed2000

Behavioral responses of humpback whales (Megaptera novaeangliae) to full-scale ATOC signals.

Loud (195 dB re 1 microPa at 1 m) 75-Hz signals were broadcast with an ATOC projector to measure ocean temperature. Respiratory and movement behaviors of humpback whales off North Kauai, Hawaii, were examined for potential changes in response to these transmissions and to vessels. Few vessel effects were observed, but there were fewer vessels operating during this study than in previous years. No overt responses to ATOC were observed for received levels of 98-109 dB re 1 microPa. An analysis of covariance, using the no-sound behavioral rate as a covariate to control for interpod variation, found that the distance and time between successive surfacings of humpbacks increased slightly with an increase in estimated received ATOC sound level. These responses are very similar to those observed in response to scaled-amplitude playbacks of ATOC signals [Frankel and Clark, Can. J. Zool. 76, 521-535 (1998)]. These similar results were obtained with different sound projectors, in different years and locations, and at different ranges creating a different sound field. The repeatability of the findings for these two different studies indicates that these effects, while small, are robust. This suggests that at least for the ATOC signal, the received sound level is a good predictor of response.

Animals↗

PubMed2002

Low-frequency acoustic pressure, velocity, and intensity thresholds in a bottlenose dolphin (Tursiops truncatus) and white whale (Delphinapterus leucas).

The relative contributions of acoustic pressure and particle velocity to the low-frequency, underwater hearing abilities of the bottlenose dolphin (Tursiops truncatus) and white whale (Delphinapterus leucas) were investigated by measuring (masked) hearing thresholds while manipulating the relationship between the pressure and velocity. This was accomplished by varying the distance within the near field of a single underwater sound projector (experiment I) and using two underwater sound projectors and an active sound control system (experiment II). The results of experiment I showed no significant change in pressure thresholds as the distance between the subject and the sound source was changed. In contrast, velocity thresholds tended to increase and intensity thresholds tended to decrease as the source distance decreased. These data suggest that acoustic pressure is a better indicator of threshold, compared to particle velocity or mean active intensity, in the subjects tested. Interpretation of the results of experiment II (the active sound control system) was difficult because of complex acoustic conditions and the unknown effects of the subject on the generated acoustic field; however, these data also tend to support the results of experiment I and suggest that odontocete thresholds should be reported in units of acoustic pressure, rather than intensity.

Acoustics↗

PubMed2004

Tracking sperm whale (Physeter macrocephalus) dive profiles using a towed passive acoustic array.

A passive acoustic method is presented for tracking sperm whale dive profiles, using two or three hydrophones deployed as either a vertical or large-aperture towed array. The relative arrival times between the direct and surface-reflected acoustic paths are used to obtain the ranges and depths of animals with respect to the array, provided that the hydrophone depths are independently measured. Besides reducing the number of hydrophones required, exploiting surface reflections simplifies automation of the data processing. Experimental results are shown from 2002 and 2003 cruises in the Gulf of Mexico for two different towed array deployments. The 2002 deployment consisted of two short-aperture towed arrays separated by 170 m, while the 2003 deployment placed an autonomous acoustic recorder in tandem with a short-aperture towed array, and used ship noise to time-align the acoustic data. The resulting dive profiles were independently checked using single-hydrophone localizations, whenever multipath reflections from the ocean bottom could be exploited to effectively create a large-aperture vertical array. This technique may have applications for basic research and for real-time mitigation for seismic airgun surveys.

Acoustics↗

PubMed2005

Source of the North Pacific "boing" sound attributed to minke whales.

During a recent cetacean survey of the U.S. waters surrounding the Hawaiian Islands, the probable source of the mysterious "boing" sound of the North Pacific Ocean was identified as a minke whale, Balaenoptera acutorostrata. Examination of boing vocalizations from three research surveys confirms previous work that identified two distinct boing vocalization types in the North Pacific. The eastern boing (n = 22) has a pulse repetition rate of 92 s(-1) and a duration of 3.6 s and was found only east of 138 degrees W. The central boing (n = 106) has a pulse repetition rate of 115 s(-1) and a duration of approximately 2.6 s and was found only west of 135 degrees W. Central boing vocalizations produced by a single source (n = 84) indicate that variation in repetition rate and duration of the calls of the individual were not significantly different than the variation among individuals of the same boing type. Despite a slight latitudinal overlap in the vocalizations, pulse repetition rates of the eastern and central boings were distinct.

Acoustics↗

PubMed2006

Vocal behavior of resident killer whale matrilines with newborn calves: the role of family signatures.

Studies of the vocal behavior of resident killer whales or orcas, Orcinus orca, in British Columbia have shown that matrilines have unique call repertoires consisting of up to 17 different call types. These call types cannot be attributed exclusively to specific behaviors, and their function in social contexts is poorly understood. This study investigated the change in call patterns of three resident matrilines in a changed social environment, before and up to one year after the birth of a calf. Acoustic data were collected with a network of hydrophones and were supplemented by visual observations. Call use changed distinctly after the birth of a calf in all three observed matrilines. All call types that were recorded in control situations were also recorded in postbirth situations; however, aberrant versions of discrete calls and excitement calls made up a higher proportion of calls after birth. Most conspicuously, family-specific call types occurred significantly more frequently in the days following a birth in two of the three matrilines and gradually returned to prebirth values within 2 weeks. Their increased use after a calf's birth may facilitate the learning process of this "acoustic family badge" and thereby help to recognize and maintain cohesion with family members.

Age Factors↗

PubMed2006

Information entropy of humpback whale songs.

The structure of humpback whale (Megaptera novaeangliae) songs was examined using information theory techniques. The song is an ordered sequence of individual sound elements separated by gaps of silence. Song samples were converted into sequences of discrete symbols by both human and automated classifiers. This paper analyzes the song structure in these symbol sequences using information entropy estimators and autocorrelation estimators. Both parametric and nonparametric entropy estimators are applied to the symbol sequences representing the songs. The results provide quantitative evidence consistent with the hierarchical structure proposed for these songs by Payne and McVay [Science 173, 587-597 (1971)]. Specifically, this analysis demonstrates that: (1) There is a strong structural constraint, or syntax, in the generation of the songs, and (2) the structural constraints exhibit periodicities with periods of 6-8 and 180-400 units. This implies that no empirical Markov model is capable of representing the songs' structure. The results are robust to the choice of either human or automated song-to-symbol classifiers. In addition, the entropy estimates indicate that the maximum amount of information that could be communicated by the sequence of sounds made is less than 1 bit per second.

Acoustics↗

PubMed2006

Classification of vocalizations of killer whales using dynamic time warping.

A large number of killer whale sounds have recently been classified perceptually into Call Types. [A. Hodgins-Davis, thesis, Wellesley College (2004)]. The repetition rate of the pulsed component of five or more examples of each call type has been calculated using a modified form of the FFT based comb-filter method. A dissimilarity or distance matrix for these sounds was calculated using dynamic time warping to compare their melodic contours. These distances were transformed into a component space using multidimensional scaling and the resulting points were clustered with a kmeans algorithm. In grouping 57 sounds into 9 call types, a single discrepancy between the perceptual and the automated methods occurred.

Algorithms↗

PubMed1999

Computer models for masked hearing experiments with beluga whales (Delphinapterus leucas).

Environmental assessments of manmade noise and its effects on marine mammals need to address the question of how noise interferes with animal vocalizations. Seeking the answer with animal experiments is very time consuming, costly, and often infeasible. This article examines the possibility of estimating results with software models. A matched filter, spectrogram cross-correlation, critical band cross-correlation, and a back-propagation neural network detected a beluga vocalization in three types of ocean noise. Performance was compared to masked hearing experiments with a beluga whale [C. Erbe and D. M. Farmer, Deep-Sea Res. II 45, 1373-1388 (1998)]. The artificial neural network simulated the animal data most closely and raised confidence in its ability to predict the interference of a variety of noise source with a variety of vocalizations.

Animals↗

PubMed2000

Recognizing transient low-frequency whale sounds by spectrogram correlation.

A method is described for the automatic recognition of transient animal sounds. Automatic recognition can be used in wild animal research, including studies of behavior, population, and impact of anthropogenic noise. The method described here, spectrogram correlation, is well-suited to recognition of animal sounds consisting of tones and frequency sweeps. For a sound type of interest, a two-dimensional synthetic kernel is constructed and cross-correlated with a spectrogram of a recording, producing a recognition function--the likelihood at each point in time that the sound type was present. A threshold is applied to this function to obtain discrete detection events, instants at which the sound type of interest was likely to be present. An extension of this method handles the temporal variation commonly present in animal sounds. Spectrogram correlation was compared to three other methods that have been used for automatic call recognition: matched filters, neural networks, and hidden Markov models. The test data set consisted of bowhead whale (Balaena mysticetus) end notes from songs recorded in Alaska in 1986 and 1988. The method had a success rate of about 97.5% on this problem, and the comparison indicated that it could be especially useful for detecting a call type when relatively few (5-200) instances of the call type are known.

Animals↗

PubMed2001

Origin of whales from early artiodactyls: hands and feet of Eocene Protocetidae from Pakistan.

Partial skeletons of two new fossil whales, Artiocetus clavis and Rodhocetus balochistanensis, are among the oldest known protocetid archaeocetes. These came from early Lutetian age (47 million years ago) strata in eastern Balochistan Province, Pakistan. Both have an astragalus and cuboid in the ankle with characteristics diagnostic of artiodactyls; R. balochistanensis has virtually complete fore- and hind limbs. The new skeletons are important in augmenting the diversity of early Protocetidae, clarifying that Cetacea evolved from early Artiodactyla rather than Mesonychia and showing how early protocetids swam.

Animals↗

PubMed2004

Cumulative sperm whale bone damage and the bends.

Diving mosasaurs, plesiosaurs, and humans develop dysbaric osteonecrosis from end-artery nitrogen embolism ("the bends") in certain bones. Sixteen sperm whales from calves to large adults showed a size-related development of osteonecrosis in chevron and rib bone articulations, deltoid crests, and nasal bones. Occurrence in animals from the Pacific and Atlantic oceans over 111 years made a pathophysiological diagnosis of dysbarism most likely. Decompression avoidance therefore may constrain diving behavior. This suggests why some deep-diving mammals show periodic shallow-depth activity and why gas emboli are found in animals driven to surface precipitously by acoustic stressors such as mid-frequency sonar systems.

Animals↗

PubMed1960

Physiological measurements on a live whale.

Temperature, respiration, and electrocardiographic measurements were made on a stranded 45-ft. finback whale. This proved to be a practical means of getting physiological information on the large cetaceans.

Animals↗