No abstract

No abstract

No abstract

No abstract

The corpora albicantia (CAs) from the ovaries of 39 common dolphins (Delphinus delphis) caught in driving fisheries were used, and histologically and immunohistochemically examined. The area of each corpus albicans (CA) and the proportion of that area occupied by elastin were measured using NIH-image software. In all CAs, elastoid material (EM) was apparent although EM area varied in each CA. CAs increased in number with dolphin age. Smaller CAs contained a higher proportion of EM. EM was completely digested by elastase, but not by collagenase. Furthermore, EM was immunostained with anti-␣-elastin antibody. These results demonstrated that EM was elastin. The present study is the first to describe the presence of elastin 1 Current address: Biologging Institute, 2-31-10, Rex Yushima 301, Yushima Bunkyo-ku, Tokyo 113-0034, Japan. 819 820 MARINE MAMMAL SCIENCE, VOL. 22, NO. 4, 2006 in cetacean CAs. The higher proportion of elastin in small-sized CAs of common dolphins is suggested as the likely cause of the persistence of CA.

Brucella, a gram-negative facultative intracellular bacterium, is a causative agent of brucellosis, a worldwide zoonotic disease, which is known to cause reproductive disorders or abortion in domesticated animals. Six species of Brucella have been recognized in terrestrial animals: Brucella abortus, B. melitensis, B. suis, B. ovis, B. canis, and B. neotomae (5). The broad spectrum of Brucella infection has recently been expanded to include marine mammals. Brucella strains from marine mammals have been shown microbiologically to be distinct from the six terrestrial Brucella species (1, 6, 10). Molecular studies of strains from marine mammals inhabiting the North Atlantic also indicated that they represent a group separate from terrestrial strains (1-4). It is difficult to evaluate the infertility in wild marine mammals infected with Brucella; however, abortion of captive bottlenose dolphins (Tursiops truncatus) has been reported (13). We previously found marked granular gonads with caseation or calcification in 35% (14/40) of common minke whales (Balaenoptera acutorostrata) examined in the western North Pacific (15). Antibodies to Brucella were detected in 38% (15/40) of serum samples from the common minke whales (15). We detected a new variant of Brucella gene copies (JM13/00) in these granular testes using the polymerase chain reaction (PCR) with Brucella-specific primers (16).Brucella outer membrane protein 2 (Omp2) genes encode 36-38-kD porins, pore-forming proteins (7). Terrestrial isolates have two gene copies, omp2a and omp2b, which share approximately 85% DNA sequence identity (8). They are separated by about 800 bp on the chromosome and oriented in opposite directions. The exception is B. ovis from goats, which has two copies of omp2a (9). Brucella strains from North Atlantic seals have omp2a and omp2b, whereas North Atlantic cetacean strains have two gene copies of omp2b (1, 3). Brucella from North Pacific common minke whales has been shown to have omp2a and omp2b, like terrestrial and Atlantic seal strains (16). Its omp2a sequence was completely identical to that of Atlantic seal strain B2/94, whereas its omp2b formed a subclade in Brucella omp2b genes independent of either Atlantic marine strains or terrestrial strains (16). Thus, analysis of omp2 is thought to be useful to understand the diversity and classification of Brucella strains. Terrestrial Brucella Omp2a and Omp2b porins have been shown to form 16-stranded β-barrels with surfaceexposed peptide loops (14,17 Abstract: In the Pacific common minke whale (Balaenoptera acutorostrata), a new variant of Brucella has been detected using the polymerase chain reaction. Detailed analysis of the porin protein genes, omp2a and omp2b from the whale Brucella showed that these two genes have some motifs in common with Atlantic marine strains in the 5'-terminal one-third region. On the other hand, the nucleotide sequences in the 3'-terminal two-thirds region of the two genes were almost identical to the respective genes of terrestrial strains. Thus, Pacific ...

No abstract

The present study examined the growth of baleen plates with interpretation of the V-shape notch that appears on the baleen plate among Antarctic minke whales Balaenoptera bonaerensis. A total of 1,654 baleen plates including those from foetuses collected by the Japanese whale research program under special permit in the Antarctic （JARPA; 1,218 individuals） and commercial whaling （436 individuals） in Area IV were used for the present analysis, with relevant biological information. The total baleen plate length increased with body length and reached the maximum of 261.8 mm at larger than 7.9 m and 278.3 mm at larger than 8.4 m in males and females, respectively. The V-shape notch was found in all animals smaller than 5.5 m but not in the foetal stage, suggesting that the notch might form in the neonate. It seemed that the V-shape notch completely disappeared due to wear at the body length of around 6.4 m.