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A new serotype of calicivirus, designated as San Miguel sea lion virus type 6 (SMSV-6), was isolated from vesicular lesions on the flipper of a California sea lion pup. Serologic studies show that SMSV-6 neutralizing antibodies (SN) occur frequently among California sea lions and occasionally among northern fur seals. Feral swine, 1- to 6-week elephant seal pups and grey whales tested negative for SMSV-6 antibody.
Murine monoclonal antibodies (MAbs) were generated against phocid herpesviruses (PhHV 2557/Han88 and 7848/Han90) isolated from European harbour seals (Phoca vitulina), and against strains of both felid (FHV strain FVR 605) and canid herpesviruses (CHV isolate 5105/Han89). MAbs were characterized with respect to certain biological properties and used to outline antigenicity profiles of isolates of PhHV (n = 8), FHV (n = 7) and CHV (n = 3) in enzyme immunoassays employing fixed infected cells. A close antigenic relationship between herpesviruses derived from pinnipeds and terrestrial carnivores became evident: The majority of the MAbs was directed against epitopes which were expressed by at least two of the viral species tested. A number of MAbs detected epitopes which were conserved between all isolates of PhHV, FHV and CHV. A few MAbs recognized type-specific B-cell epitopes and facilitated the identification of single viral species. Moreover, the PhHV isolate 7848/Han90 was antigenically distinguishable both from seven other phocid herpesvirus isolates and from FHV or CHV. PhHV 7848/Han90 proved to be antigenically distinct from all other viruses tested when examined by cross neutralization utilizing various reconvalescent and hyperimmune sera. Although more data are needed to ensure that PhHV 7848/Han90 indeed is a new genuine seal herpesvirus, the preliminary clustering of two groups of phocid herpesvirus isolates, tentatively designated PhHV-1 (type isolate 2557/Han88) and PhHV-2 (represented by 7848/Han90), seems to be justified. By using selected MAbs an unambiguous identification and typing of herpesvirus isolates derived from marine mammals and terrestrial carnivores is significantly facilitated.
Infection studies in harbour seal (Phoca vitulina) were conducted with the Snyder-Hill strain of canine distemper virus (CDV) that is virulent for dog and mink. The inoculated seals showed clinical symptoms which were to some degree similar to those observed in CDV infections of sensitive species of carnivores. Viral replication in lymphoid cells was followed by an extended period of immunosuppression. The results did not provide conclusive evidence for viral replication in surface epithelia of seals, and accordingly no spread of the infection to contact seals and mink was demonstrated. The pathogenicity of the infection did not increase upon a second viral passage in seal. The serological data showed that CDV-infected seals mounted an early virus specific antibody response. Overall, the results indicated that the harbour seal was not especially sensitive to CDV infection. The differences in the in vivo biological properties of CDV and PDV add to the distinction between these viruses at the genomic and antigenic levels.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
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Caliciviruses (CVs) include at least 42 distinct serotypes. Seventeen CV serotypes have been isolated from marine sources and are called San Miguel sea lion caliciviruses (SMSVs). CVs also have been isolated from reptiles, primates, and other terrestrial animals. Nucleotide sequences from portions of genome of prototype strains for six SMSV serotypes, the reptile CV, Cro-1, the cetacean CV, Tur-1, and the primate CV, Pan-1, are presented. cDNA products of the polymerase (all strains characterized) and capsid (SMSV-17) regions were produced by reverse transcription-polymerase chain reaction using Pan-1 primers. Comparisons of nucleotide and amino acid identity among these and published CV sequences indicated that the nine characterized CVs fall into a phylogenetic group that includes SMSV-1 and SMSV-4 and that is more closely related to other characterized animal CVs than to most human CVs. The phylogenetic analysis also indicated that distinct genera exist among the Caliciviridae. SMSV-17 and SMSV-4 are predicted to be closer to each other than other caliciviruses of known serotype; 574 (82%) of the 704 amino acids in the SMSV-17 and SMSV-4 capsid genes were identical.
Large seals such as northern and southern elephant seals and Weddell seals are able to dive for startling duration and enormous depth. The current dive duration record is 120 minutes (recorded for the southern elephant seal); the current depth record is 1.5 km (recorded for the northern elephant seal). Equally striking is the widespread observation that these seals when at sea spend close to 90% of the time submerged and often at great depth. For practical purposes, these species can be viewed as true mesopelagic animals when they are at sea. A review of current knowledge indicates that low power output but high efficiency metabolic functions of skeletal muscles coupled with inherently low (and potentially further suppressible) metabolic rates constitute strategic biochemical components in the 'making' of a mesopelagic mammal.
There are several groups of animals that are adapted for extremely long duration fasting as part of their reproductive cycle. Penguins, bears and seals routinely fast without food or water for months at time. However, they do not 'starve', as the biochemical implications of starving are very different from those of successful fasting. There are distinct biochemical adaptations in lipid, carbohydrate and especially protein metabolism that allow these animals to survive. It appears, at least for penguins and seals, that the duration of the fast may be limited by changes that occur in biochemical regulation near the ned of the fast. In all of these species, the biochemistry of fasting and the ecological and behavioral demands of their breeding cycles are closely interrelated.
Ornithine carbamoyltransferase (EC 2.1.3.3) has been determined in homogenates of liver of the sei whale (Balaenoptera borealis), the bottle-nose dolphin (porpoise) (Tursiops truncatus) and California sea lion (Zalophus californianus). These marine mammals show levels of this ornithine-urea cycle enzyme which are typical of terrestrial mammals.
The pineal gland of newborn elephant seals and Weddell seals is larger than in adult females. The gland is considerably larger at birth in Weddell seals than in elephant seals. The former experience greater extremes of temperature. Plasma melatonin concentrations in excess of 2000 pg/ml were recorded in the first days of life, compared with 20-50 pg/ml in adults.
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Plasma was used from rat, mouse, guinea pig, rabbit, dog, cat, sheep, goat, monkey, horse, pig, cow, fox, mink, porpoise, deer, manatee, seal, elephant, raccoon, pigeon, macaw, and humans; clotting time and gel formation activities by the compact-colony forming active substance (CCFAS) extracted from a strain of Staphylococcus aureus and relative staphylococcal clumping factor reaction were determined. Experimental results showed that every plasma was clotted and gel formation of plasma was observed by the CCFAS, however, although it was shown by the other plasmas, no clumping-factor reaction was observed with plasma from guinea pig, goat, and elephant.