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Primary structure of pronghorn pancreatic ribonuclease: close relationship between giraffe and pronghorn.

Pancreatic ribonuclease from pronghorn (Antilocapra americana) was isolated and its amino acid sequence was determined from a tryptic digest of the performic acid-oxidized protein. Peptides were positioned by homology with other ribonucleases. Only peptides that differed in amino acid composition from the corresponding peptides of ox or goat ribonucleases were sequenced. In a most parsimonius tree of pancreatic ribonucleases, pronghorn and giraffe were placed together and these two were placed with the bovids, leaving the deer as a taxon separate from the other ruminants. The amino acid replacements that determine this tree topology are three rarely occurring replacements shared by pronghorn and giraffe. Notwithstanding their close phylogenetic relationship, both ribonucleases differ strongly in extent of glycosidation, net charge and antigenic properties.

Amino Acid Sequence↗

Comparison of various immunological methods for distinguishing among mammalian pancreatic ribonucleases of known amino acid sequence.

Fourteen mammalian pancreatic ribonucleases of known amino acid sequence were compared by 1 or more of 3 different immunological methods: standard quantitative micro-complement fixation, spot-plate micro-complement fixation, and inhibition of phage inactivation. It was found that, while the results obtained by the 3 techniques were correlated with one another, the standard micro-complement fixation procedure was most versatile, economical of materials, and easiest to execute. The standard MC'F technique was more sensitive than the spot-plate technique to differences in amino acid sequence. The inhibition of phage inactivation method was more sensitive than the standard method for measuring differences among closely related RNases but proved impractical for amino acid differences over 15%; the MC'F method could be extended to at least 30% sequence differences. The standard method, moreover, readily detected the single amino acid difference between dromedary and camel RNases. A linear relationship was found between immunological distance (y) in the MC'F test and percent sequence difference (x) which fit the equation y = 7x. The strength of the correlation between immunological distance and percent sequence difference is consistent with the proposal that a large fraction of the evolutionary substitutions of amino acids in ribonuclease are immunologically detectable. This could be explained either by a multideterminant hypothesis or by a pauci-determinant hypothesis which says that substitutions occurring outside determinants produce small conformational changes influencing determinant reactivity.

Amino Acid Sequence↗

Functional aspects of hemoglobin evolution in the mammals.

Comparative studies of red cells 2, 3 Diphosphoglycerate (DPG) and its effect on hemoglobin oxygen affinity from a taxonomically diverse set of mammals indicate two anomalous groups: members of the superfamilies Bovoidea (Actiodactyla) and Feloidea (Carnivora). In both taxa all of the individuals assayed had very low or unmeasurable quantities of DPG and red cell lysates with little, if any, DPG effect as measured by the change in oxygen affinity in the absence and presence of the phosphate. However, in both groups compensatory changes have occurred in hemoglobin structure and function so as to reduce the native oxygen affinity and thus cause them to resemble the hemoglobins of DPG-utilizing mammals as they occur in the setting of the red cell. We conclude that this parallelism of function is the result of convergent evolution.

Amino Acid Sequence↗

The band 3-rich membrane of llama erythrocytes: studies on cell shape and the organization of membrane proteins.

The erythrocyte membrane of the llama was characterized in comparison to that of the human. The llama erythrocyte was an elliptical disk that resisted shape alterations in hyperosmotic buffers and following metabolic depletion, both of which induce speculation of the human red cell. Lysophosphatidylcholine incorporation produced minor serrations of the edge of the llama disk but no spicules, whereas human red cells became sphero-echinocytes. The polypeptide profiles in the membranes of the two species were similar, except for several noteworthy differences: a marked elevation in the relative content of band 3; the absence of membrane-bound band 6; and simpler glycoprotein pattern in the llama. The concentration of band 3 in llama was about two and a half to three times that in the human and intramembrane particles in the protoplasmic leaflet of freeze-fractured llama membrane were correspondingly increased. The selective solubilization of bands 1, 2 and 5 in low ionic strength buffer, and all of the peripheral proteins in high alkaline buffer were similar except for increased retention of ankyrin by the llama membrane. These data suggest a similar disposition of membrane proteins. The llama membrane was markedly resistant to the solubilization of integral proteins by the nonionic detergent, Triton X-100. This property and the general resistance to shape changes may be related to the high concentration of band 3.

Animals↗

Ontogenic development of peptide hormones in the mammalian fetal pancreas.

The ontogeny of insulin, glucagon, PP and somatostatin in the mammalian fetal pancreas has been examined in recent years largely by immunocytochemistry and in some instances by radioimmunoassay. Complete ontogenic data are available only for the rat, human, pig and sheep. Figure 3 compares the time of appearance of the endocrine cell-types within the fetal pancreas when the periods of gestation of the four species are converted to a uniform scale. The striking ontogenic difference in the rat probably reflects the immaturity of the rodent fetus at birth compared with the human, pig and sheep. In the fetal pancreas, differences in cell number of glucagon and PP cells in the dorsal and ventral lobes become apparent from an early gestational period. Factors responsible for the functional and structural maturation of the fetal pancreatic endocrine cells and the processes involved in pancreatic organogenesis are poorly understood. Studies in these areas would have clinical implications since it may be possible in the future to employ agents for selective replication of fetal beta-cells for transplantation in patients with Type I diabetes, bearing in mind that such cells must have the capacity to respond to normal stimuli and repressors when transplanted. The presence of the other islet cell-types may be obligatory for these appropriate responses. This would require a more complete knowledge of those factors which produce the normal selectivity of the four hormonal cell-types.

Animals↗

Man's strategy in domestication - a synthesis of new research trends.

The minimum brain size possible in the relevant wild species and certain colour types which, because of alterations in the neurotransmitter system caused by the respective colour genes, are related to behavioural traits diverging from the wild animals norm appear to be first-rate bases for domestication either separately or in combination.

Animal Husbandry↗

Different rates of substitution may produce different phylogenies of the eutherian mammals.

In an attempt to resolve some points of branching order in the phylogeny of the eutherian mammals, a phylogenetic analysis of 26 nuclear and 6 mitochondrial genes was undertaken using a maximum likelihood method on a constant rate stochastic model of molecular evolution. Seventeen of the nuclear genes gave a primates/artiodactyls grouping highest support whereas three of the mitochondrial genes found a rodents/artiodactyls grouping to be best supported. The primates/rodents grouping was never the best supported. On the assumption that rodents are indeed an outgroup to primates and artiodactyls and that the latter taxa diverged 70 million years ago, an estimation was made, for each gene, of the time of divergence of the rodent lineage. In most cases such estimates were beyond the limits set by present interpretations of the paleontological record as were many estimates of the divergence time of mouse and rat. These results suggest that, although there is locus variation, the divergent position of the rodent lineage may be an artifact of an elevated rate of nucleotide substitution in this order.

Animals↗

Comparison of the reactions of the compact-colony forming active substance (CCFAS) to the clumping-factor reaction in a strain of Staphylococcus aureus with animal plasma.

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.

Animals↗

Pattern and timing of evolutionary divergences among hominoids based on analyses of complete mtDNAs.

We have examined and dated primate divergences by applying a newly established molecular/ paleontological reference, the evolutionary separation between artiodactyls and cetaceans anchored at 60 million years before present (MYBP). Owing to the morphological transformations coinciding with the transition from terrestrial to aquatic (marine) life and the large body size of the animals (which makes their fossils easier to find), this reference can be defined, paleontologically, within much narrower time limits compared to any local primate calibration marker hitherto applied for dating hominoid divergences. Application of the artiodactyl/ cetacean reference (A/C-60) suggests that hominoid divergences took place much earlier than has been concluded previously. According to a homogeneous-rate model of sequence evolution, the primary hominoid divergence, i.e., that between the families Hylobatidae (gibbons) and Hominidae, was dated at approximately 36 MYBP. The corresponding dating for the divergence between Pongo (orangutan) and Gorilla-Pan (chimpanzee) -Homo is approximately 24.5 MYBP, that for Gorilla vs Homo-Pan is approximately 18 MYBP, and that for Homo vs Pan approximately 13.5 MYBP. The split between Sumatran and Bornean orangutans was dated at approximately 10.5 MYBP and that between the common and pygmy chimpanzees at approximately 7 MYBP. Analyses of a single gene (cytochrome b) suggest that the divergence within the Catarrhini, i.e., between Hominoidea and Old World monkeys (Cercopithecoidea), took place > 40 MYBP; that within the Anthropoidea, i.e., between Catarrhini and Platyrrhini (New World monkeys), > 60 MYBP; and that between Anthropoidea and Prosimii (lemur), approximately 80 MYBP. These separation times are about two times more ancient than those applied previously as references for the dating of hominoid divergences. The present findings automatically imply a much slower evolution in hominoid DNA (both mitochondrial and nuclear) than commonly recognized.

Animals↗

Faecal bacteria of wild ruminants and the alpine marmot.

Faecal samples from 60 red deer (Cervus elaphus), 13 roe deer (Capreolus capreolus), 7 chamois (Rupicapra rupicapra), 41 alpine marmot (Marmota marmota) and soils mixed with deer faeces from the Stelvio National Park were examined for Campylobacter sp. and Salmonella sp. with negative results. The same material, especially deer faeces, was a habitat highly suitable for Yersinia sp.: Y. enterocolitica (two biotypes) was isolated twice, Y. kristensenii (two serotypes) was isolated 19 times, Y. frederiksenii and Y. intermedia were isolated once. Antibiotic-resistant Escherichia coli were isolated from 16 specimens from wild ruminants, one from marmot and two from feeding places.

Animals↗

Serological evidence of bluetongue in game animals in Botswana.

Using the Agar Gel Precipitin technique the sera of 397 African buffalo (Syncerus caffer) and 90 sera of other common game species were examined for bluetongue antibodies. Of the adult buffalo 283 out of 325 (87 per cent) were positive. Buffalo calves were positive in 25 out of 72 cases (35 per cent). Positive reactions were also recorded in lechwe (Kobus leche), tsessebe (Damaliscus lunatus), red hartebeeste (Alcelaphus buselaphus), gemsbok (Oryx gazella), sable (Hippotragus niger) and impala (Aepyceros melampus).

Animals↗