THE OCULAR SECRETIONS OF THE BOTTLENOSE DOLPHIN TURSIOPS TRUNCATUS

A viscous ocular secretion streams from the eyes of bottlenose dolphins, Tursiops truncatuss , removed from the water. The chemical composition and environmentally adaptive implications of this substance continue to perplex curators and scientists. Secretions from three dolphins were examined for deviations from literature values for normal human and terrestrial mammalian tear film components. Osmolality (= 470 mOsm/kg), pH (= 8.44) and glucose (= 26.58 mg/100 ml) were significantly greater than human and terrestrial mammalian tear film values; while lysozyme (= 0.005 mg/ml) and total cholesterol (= 0.17 μg/μ1) were significantly less. Refractive index, sodium ion concentration, and potassium tear to plasma ratios in the dolphin ocular secretion did not deviate significantly from human or terrestrial mammalian tears. Electrophoresis of dolphin tears yielded four major protein bands (probably lactoferrin, serum albumin, teat specific prealbumin, and lysozyme) and high molecular weight glycoproteins similar to human tears. The chemical composition of the T. truncatus ocular secretion suggests that the circumorbital conjunctival gland may be analogous (relative to refractive index, electrolytes, and component protein) to the terrestrial lachrymal gland. At the functional level the T. truncatus ocular secretion may reduce hydrodynamic resistance on the cornea and protect it from bacterial invasion.     

POPULATION STRUCTURE OF THE BOTTLENOSE DOLPHIN (TURSIOPS TRUNCATUS) AS DETERMINED BY RESTRICTION ENDONUCLEASE ANALYSIS OF MITOCHONDRIAL DNA

Abstract: Restriction fragment length polymorphisms of mitochondrial DNA (mtDNA) were used to test for population subdivision in the bottlenose dolphin (Tursiops truncatus). Atlantic and Pacific dolphin mtDNA samples exhibited distinctly different haplotypes (approximately 2.4% sequence divergence), indicating a lack of gene exchange. Within the Atlantic Ocean, mtDNA samples from the Gulf of Mexico and the Atlantic Coast were also found to be distinct, with a sequence divergence of approximately 0.6%. The Atlantic Coast–Gulf of Mexico dichotomy is consistent with patterns of genetic variation from other marine and coastal organisms from this region, and supports the hypothesized role of bio-geographic events in promoting the divergence of these and other forms. Regional differentiation was identified along the Atlantic Coast, whereas low sequence divergences among haplotypes and consistent haplotype frequencies across populations suggested considerable gene exchange among Gulf of Mexico populations. A highly divergent haplotype found in two individuals from two localities in the Gulf of Mexico is best explained by dispersal from either a distinct offshore Gulf stock or an unsampled Atlantic Coast stock. Additional samples are required to test for the existence of a distinct offshore race and, if it exists, to identify its distribution and contribution to population structure.     

CHARACTERIZATION OF A BOTTLENOSE DOLPHIN (TURSIOPS TRUNCATUS) KIDNEY EPITHELIAL CELL LINE

Abstract: An epithelial cell line, Carvan dolphin kidney (CDK), isolated from a prematurely born female bottlenose dolphin, Tursiops truncatus , exhibited growth characteristics not previously reported for cetacean cells in culture. CDK cells were cytokeratin positive and demonstrated a maximum doubling time of 1.31 days, with plating and colony forming efficiencies approaching 100% for the early population doublings. Despite an unusually efficient colony-forming ability and rapid growth, these cells were neither transformed nor immortal, displaying normal contact inhibition, anchorage dependence, and the requirement for high concentrations of fetal bovine serum in the growth medium. CDK cells exhibited age-dependent changes in growth rate, colony-forming efficiency, and cytoplasmic profile, and showed a finite lifespan of about 50 population doublings and a stable 2N = 44 karyotype which correlates with previously reported cytogenetic analyses. Velocity sedimentation analysis showed that CDK cells contained nuclear aryl hydrocarbon receptor (Ah), indicating their potential to be induced for cytochrome P450. These data suggest that CDK cells may have utility as an in vitro toxicological model for evaluating hydrocarbon contaminant effects on Tursiops truncatus , a protected marine mammal.     

RAY ENCOUNTERS AS A MORTALITY FACTOR IN ATLANTIC BOTTLENOSE DOLPHINS (TURSIOPS TRUNCATUS)

Ray spines were found associated with various tissues on necropsy of seven Atlantic bottlenose dolphins ( Tursiops truncatus ). In at least six cases they were considered a major factor in the death of the animal. Three mature Tursiops had ray spines located in the lung parenchyma. In two other dolphins the ray spine punctured the lateral chest wall without entering the lung tissue. A sixth Tursiops contained a ray spine located in the liver tissue, while a seventh animal had a ray spine lodged in the pancreas. Five of the dolphins were wild individuals and two had been in captivity for more than one year. These findings indicate that beached dolphins and dolphins in captivity with a chronic history of illness should be examined for the presence of ray spines. Caution should be used in maintaining mixed exhibits of dolphins with stingray species.     

DOLPHIN THYROID AND ADRENAL HORMONES: CIRCULATING LEVELS IN WILD AND SEMIDOMESTICATED TURSIOPS TRUNCATUS, AND INFLUENCE OF SEX, AGE, AND SEASON

Biological and environmental influences on circulating adrenal and thyroid hormones were investigated in 36 wild and 36 semidomesticated Atlantic bottlenose dolphins, Tursiops truncatus, matched by age, sex, and time of year when the samples were collected. Serum concentrations of thyroxine (free [fT41 and total [tT4]), triiodothyronine (free [fT3], total [tT3], and total reverse [rT37), cortisol, and aldosterone were determined by radio-immunoassay, Wild female dolphins had significantly higher levels of tT4, fT4 and fT3, an effect that was possibly related to reproduction and lactation. Semidomesticated females had higher tT3 than their wild counterparts. fT4 declined with age in wild dolphins, whereas rT3 was greatest in the older animals. Cortisol and aldosterone were both higher in wild animals sampled after a variable interval of up to four hours after encirclement by capture net. The pattern of adrenal hormone release suggested a mild stress response. Levels of both adrenal hormones were low in semidomesticated dolphins conditioned to present voluntarily their tails for blood sampling, an approach that appears to yield specimens representative of resting values for these constituents.     

CROSS-REACTIVITY OF ANTIBODIES TO HUMAN ANTIGENS WITH TISSUES OF THE BOTTLENOSE DOLPHIN, TURSIOPS TRUNCATUS, USING IMMUNOPEROXIDASE TECHNIQUES

Cross-species reactivity of 53 antibodies developed against human antigens was evaluated in the bottlenose dolphin Tursiops truncatus , using immunoperoxidase techniques, Strong cross-reactivity was demonstrated with antibodies against intermediate filaments, most hormones, but few leukocyte antigens. S100, NSE, F8RA, Factor XIIIa, and lactalbumin antibodies reacted, while HMB45, EMA, PLAP, and PSA did not. Polyclonal antibodies are much more likely to cross-react than are monoclonal antibodies. Twenty-four of 30 (80%) of polyclonals cross-reacted, while only 10 of 23 (43.5%) monoclonals cross-reacted. Some antigens are demonstrated only after using a special technique to unmask the antigen.     

AXIAL MUSCULATURE IN THE DOLPHIN (TURSIOPS TRUNCATUS): SOME ARCHITECTURAL AND HISTOCHEMICAL CHARACTERISTICS

In view of the supposition that a dolphin can swim faster than would be predicted based on its physical features and presumed muscle power potential, studies were initiated to reevaluate the assumptions made in reaching these conclusions. Several previous studies have shown that the architectural and histochemical properties of a skeletal muscle dictate its force, velocity and displacement properties. This study examined the muscle fiber lengths and tendon arrangements of the dorsal and ventral axial muscles in dolphins ( Tursiops truncatus ). Fiber type and fiber size distributions were determined to reflect the general biochemical characteristics of the musculature. The dorsal muscles had a higher mean fiber length (167 Vs. 90 mm) and the range within and across different dorsal muscles was less (141–199 vs. 37–185 mm) than in the ventral muscles. Both the dorsal and ventral muscles consisted of an overall mean of 50 percent slow twitch and 50 percent fast twitch fiber types. The fast twitch fibers were 67 percent larger (2,200 vs. 1,317 μ m ²) than the slow twitch fibers in the ventral and 38 percent larger (1,213 Vs. 879 μm²) in the dorsal muscles. In addition, the mean cross sectional area of the fibers in the ventral muscles was approximately 65 percent greater (1,750 vs. 1,072 μm²) than those in the dorsal muscles. The shorter, larger-diameter fibers of the ventral musculature give it a greater potential for force production for a given amount of muscle mass. In contrast, the dorsal muscles appear to be designed to optimize velocity and displacement, ( i.e. , longer fibers). These findings contribute to the information necessary for the determination of the power potential of the musculature of the dolphin.     

MORBILLIVIRUS INFECTION IN BOTTLENOSE DOLPHINS: EVIDENCE FOR RECURRENT EPIZOOTICS IN THE WESTERN ATLANTIC AND GULF OF MEXICO

Morbillivirus infection is widespread among odontocetes of the western Atlantic and Gulf of Mexico. Serologic evidence of infection in bottlenose dolphins, Tursiops truncatus , was first detected during an epizootic along the mid-Atlantic coast in 1987. Here, we report recurrent epizootics in the coastal dolphin population since at least the early 1980s based on serological surveys and regional stranding frequencies. The first observed epizootic of this series occurred in the Indian and Banana Rivers in 1982 and was followed by others on the mid-Atlantic coast in 1987–1988 and in the Gulf of Mexico between 1992 and 1994. This temporal pattern of infection is likely facilitated by the population size and its fragmentation into relatively discrete coastal communities. Introduction of morbillivirus into a community with a sufficient number of naive hosts may precipitate an epizootic, depending on the potential for transmission within the group. Propagation of an epizootic along the coast is probably determined by frequency of contact between adjacent communities and seasonal migrations.
Morbillivirus antibodies were also detected in serum from offshore bottlenose dolphins. The sero-prevalence in the latter may be higher than in coastal dolphins because of their close association with enzootically infected pilot whales ( Globicephala spp.). Occasional contact between offshore and coastal dolphins may provide an epizootiologic link between pilot whales and coastal dolphin communities.     

斯氏黄河猴(哺乳动物纲,灵长目)较完整下颌骨的发现

新发现的下颌骨说明斯氏黄河猴下齿式为 ２？, １,３, ３。 ｐ２为双根齿,其前后有短的齿隙;ｐ３具有低小的后跟;ｐ４未臼齿化,无下前尖,有初始的下后尖,在较大的跟盆上,有明显的下次尖和很小的下内尖？; ｍ１下前尖小,有些前后收缩（与Ｒｅｎｃｕｎｉｕｓ ｚｈｏｗｉ比较）,ｍ３下次小尖不如正模发育。下颌骨联合部倾斜,不愈合。黄河猴的下臼齿在形态上与西瓦兔猴亚科和原始类人猿──渐新猿亚科有许多共同点,但上臼齿形态差异显著。黄河猴类可能出自亚洲的ｃｅｒｃａｍｏｎｉｉｎｅ形的兔猴形灵长类。     

SOCIAL ECOLOGY OF BOTTLENOSE DOLPHINS IN THE KVARNERIĆ (NORTHERN ADRIATIC SEA)

A bottlenose dolphin community was studied from small inflatable craft from 1987 to 1994 in a relatively large area (about 800 km²) east of the islands of Loˇsinj and Cres, northern Adriatic Sea. A total of 106 individuals were photoidentified based on natural permanent marks on their dorsal fins. Most of the dolphins were resighted on a regular basis, indicating a high level of year-round site fidelity, although their range was evidently greater than the chosen study area. Dolphin density was highly variable and considerably lower than for most well-known bottlenose dolphin communities. Groups averaged seven individuals, with a mode of two. Groups entirely composed of adults were the smallest, groups with calves the largest. Group fluidity was high, seasonal and yearly changes in mean group size being also considerable. Summer was the peak calving season, with a striking variation in the number of births on alternate years. Poor evidence of shark predation was found. The social organization of this dolphin community seemed to be highly flexible, possibly as an adaptation to cope with environmental changes as well as with a limited and variable availability of prey.     

BIOCHEMICAL AND CYTOLOGICAL EVIDENCE FOR THE STIMULATION OFCLATHRIN-COATED PIT (VESICLE) FORMATION BY EXOGENOUS FOLIC ACID IN DUNALIELLA SALINA (CHLOROPHYTA)1

The effects of two kinds of molecules, Pb²⁺ and folic acid, on the formation of clathrin-coated pits and vesicles were studied in the unicellular green alga, Dunaliella salina Teod. Measurable amounts of algal clathrin were obtained in the postmicrosomal fraction from cells treated with folic acid. In contrast, algal clathrin heavy chains were below the detection limit in the postmicrosomal fraction from control and lead nitrate-treated cells. Consistent with the biochemical evidence, electron microscopy showed more clathrin-coated pits and vesicles in folic acid-treated cells compared to control cells or cells treated with lead nitrate alone. Observations of folic acid/lead nitrate-treated cells confirmed the endocytosis of Pb²⁺ through clathrin-coated pits and vesicles. As additional evidence for clathrin in the folic acid-stimulated cells of Dunaliella salina, clathrin was isolated and, for the first time in algae, the calcium-dependent reconstitution of clathrin cages was successfully obtained in vitro.     

EVIDENCE FOR A MOSAIC HYBRID ZONE IN THE GRASS SHRIMP PALAEMONETES KADIAKENSIS (PALAEMONIDAE) AS REVEALED BY MULTIPLE GENETIC MARKERS

Molecular techniques provide powerful tools for studying the geographic structure of hybrid zones and the dynamics of gene exchange between incipient species. We examined allozyme variation at five loci (PGM, GPI, MDH-1, MDH-2, and LDH) for 27 populations of Palaemonetes kadiakensis from the central, coastal, and eastern regions of Texas. Central Texas populations of P. kadiakensis exhibited highly significant linkage disequilibrium and departures from Hardy-Weinberg genotype proportions. In populations with linkage disequilibrium, allelic differences at GPI defined two types of P. kadiakensis, designated A and B. Both types existed in central Texas with little or no evidence of interbreeding, whereas the populations from all other localities showed complete introgression of type B alleles into the type A gene pool. We also examined ribosomal DNA (rDNA) and mitochondrial DNA (mtDNA) variation in a subset of populations, chosen to cover a range of geographic locations and levels of linkage disequilibrium. Two groups of mtDNA haplotypes and two restriction fragment patterns for the rDNA corresponded to allozyme type A and B individuals in populations exhibiting linkage disequilibrium. In populations with ongoing hybridization, all hybrid animals (N= 15) exhibited type A mtDNA. Exhibition of type A mtDNA indicated that type A females had mated successfully with type B males, but type B females had not mated successfully with type A males. Genotype distributions suggest reduced reproduction by hybrid offspring in central Texas populations. These patterns are consistent with a mosaic model of hybrid zone dynamics.     

GROWTH LAYER GROUPS (GLGs) IN THE TEETH OF AN ADULT BELUKHA WHALE (DELPHINAPTERUS LEUCAS) OF KNOWN AGE: EVIDENCE FOR TWO ANNUAL LAYERS

Growth layer groups (GLGs) were counted in teeth from an adult male belukha whale ( Delphinapterus leucas ) that had lived for 23 yr in captivity and was estimated to have been 14 mo at capture. As defined here, GLGs are repeating areas of alternating opaque (denser) and translucent (less dense) dentin or cementurn, or nodes at the dentin-cementum interface. A GLG involves at least one change from opaque to translucent, dense to less dense or ridge to groove, but may be further subdivided by incremental growth layers or laminations. Teeth were prepared by two techniques. Thick sections (longitudinal half sections) were examined with a dissecting microscope under reflected light. Thinner cross and longitudinal sections were x-rayed and the plates scanned with a microdensitometer. Scanning electron photomicrographs were prepared from thick sections, but SEM proved to be the least useful technique. Counts of GLGs were variable because the laminations were numerous and some surface layers had been lost from wear. Thick- and thinner-section techniques gave comparable results, and approximately 40 GLGs were counted consistently. Although captive environments are less variable than natural ones, our findings are further evidence that belukhas in the wild deposit more than one—and probably two—GLGs per year.     

CO2 ACCUMULATION BY CHLORELLA SACCHAROPHILA (CHLOROPHYCEAE) AT LOW EXTERNAL pH: EVIDENCE FOR ACTIVE TRANSPORT OF INORGANIC CARBON AT THE CHLOROPLAST ENVELOPE1

The CO₂ uptake characteristics of the acid-tolerant alga Chlorella saccharophila (Krüger) Nadson have been examined. These, together with direct estimations of internal inorganic C concentrations, indicate that air-adapted cells of this alga possess a CO₂ accumulation mechanism similar to that reported in other members of the Chlorophyceae and in Cyanophyceae. This accumulation mechanism operates at external pH values of 4 and less. Under these conditions CO₂ must be the carbon species crossing the plasmlemma, and since preliminary evidence suggests that the transport mechanism is active primary uniport of HCO₃^–, it is proposed that the site of the CO₂ accumulation mechanism is the chloroplast envelope.