52 research outputs found
The Paleocene cephalopod fauna from pebble point, Victoria (Australia)-fulcrum between two Eras
Three species belonging to three genera of early Cenozoic nautilid cephalopods are described from Paleocene aged beds of the Pebble Point and Dilwyn formations, Victoria, Australia: Aturoidea distans Teichert, Eutrephoceras victorianum Teichert, both previously known from these deposits, and Nautilus praepompilius Shimansky, previously unknown from Australia. Here we present new occurrence and paleoecological information about these three taxa based on previously and newly collected specimens from Pebble Point Formation beds, as well as presenting the first paleotemperature analyses for Australian nautiloid cephalopods of any age. We sampled for shell carbonates from the single known specimen of Nautilus praepompililus, as well as from a specimen of Aturoidea distans from the Pebble Point beds. The A. distans samples showed temperature of calcification to have been between 20 and 25°C; and for N. praepompilius the temperatures were between 18 and 21°C. There were too few samples to provide statistical analyses, yet the implication is that these two taxa inhabited different depths during calcification. For comparison, we have sampled shell carbonates from the only known extant site where two different nautilid genera coexist, Manus Island, Papua New Guinea. There, specimens of Nautilus pompilius and Allonautilus scrobiculatus calcified (1984 specimens) at temperatures of 12 to 17°C, conforming to previous measurements in the literature and significantly colder than any of the Paleocene specimens sampled here
An international effort towards developing standards for best practices in analysis, interpretation and reporting of clinical genome sequencing results in the CLARITY Challenge
There is tremendous potential for genome sequencing to improve clinical diagnosis and care once it becomes routinely accessible, but this will require formalizing research methods into clinical best practices in the areas of sequence data generation, analysis, interpretation and reporting. The CLARITY Challenge was designed to spur convergence in methods for diagnosing genetic disease starting from clinical case history and genome sequencing data. DNA samples were obtained from three families with heritable genetic disorders and genomic sequence data were donated by sequencing platform vendors. The challenge was to analyze and interpret these data with the goals of identifying disease-causing variants and reporting the findings in a clinically useful format. Participating contestant groups were solicited broadly, and an independent panel of judges evaluated their performance.
RESULTS:
A total of 30 international groups were engaged. The entries reveal a general convergence of practices on most elements of the analysis and interpretation process. However, even given this commonality of approach, only two groups identified the consensus candidate variants in all disease cases, demonstrating a need for consistent fine-tuning of the generally accepted methods. There was greater diversity of the final clinical report content and in the patient consenting process, demonstrating that these areas require additional exploration and standardization.
CONCLUSIONS:
The CLARITY Challenge provides a comprehensive assessment of current practices for using genome sequencing to diagnose and report genetic diseases. There is remarkable convergence in bioinformatic techniques, but medical interpretation and reporting are areas that require further development by many groups
Evolution of hind limb proportions in kangaroos (Marsupialia : Macropodoidea)
Kangaroos (Macropodoidea: Marsupialia) are a characteristic group of Australo-New Guinean mammals that diversified during the geographic isolation of the Australian continent in the Cenozoic. They are first recorded in the Late Oligocene, although the clade diverged from other diprotodontians around 38 million years ago (mya; Westerman et al., 2002), with early forms perhaps resembling small arboreal ‘phalangerids’ (Flannery, 1982). The purpose of this study is to examine the relationship between locomotor strategy and proportional changes in the proximal limb bones and metatarsals of a range of modern and extinct macropodoids using morphometric analyses. In addition, trends in hind limb evolution through time are investigated, firstly using only observations on extant taxa and inferring ancestral conditions on dated molecular phylogenies, and secondly by adding information from the fossil record. The results suggest that incorporating fossils can drastically change inferences about past diversity and evolutionary trends
Ecological and evolutionary significance of sizes of giant extinct kangaroos
© CSIRO 2006A method, based on femoral circumference, allowed us to develop body mass estimates for 11 extinct Pleistocene megafaunal species of macropodids (Protemnodon anak, P. brehus, P. hopei, P. roechus, Procoptodon goliah, ‘P.’ gilli, Simosthenurus maddocki, S. occidentalis, Sthenurus andersoni, S. stirlingi and S. tindalei) and three fossil populations of the extant eastern grey kangaroo (Macropus giganteus). With the possible exception of P. goliah, the extinct taxa were browsers, among which sympatric, congeneric species sort into size classes separated by body mass increments of 20–75%. None show evidence of size variation through time, and only the smallest (‘P.’ gilli) exhibits evidence suggestive of marked sexual dimorphism. The largest surviving macropodids (five species of Macropus) are grazers which, although sympatric, do not differ greatly in body mass today, but at least one species (M. giganteus) fluctuated markedly in body size over the course of the Pleistocene. Sexual dimorphism in these species is marked, and may have varied through time. There is some mass overlap between the extinct and surviving macropodid taxa. With a mean estimated body mass of 232 kg, Procoptodon goliah was the largest hopping mammal ever to exist.Kristofer M. Helgen, Rod T. Wells, Benjamin P. Kear, Wayne R. Gerdtz and Timothy F. Flanner
Implications of a new species of the Oligo-Miocene Kangaroo (Marsupialia : Macropodoidea) Nambaroo from the Riversleigh World Heritage Area, Queensland, Australia
Copyright © 2007 Paleontological Societ
Gq-Dependent Signaling Upregulates COX2 in Glomerular Podocytes
Accumulating evidence suggests that upregulation of cyclooxygenase 2 (COX2) in glomerular podocytes promotes podocyte injury. Because Gq signaling activates calcineurin and calcineurin-dependent mechanisms are known to mediate COX2 expression, this study investigated the role of Gqα in promoting COX2 expression in podocytes. A constitutively active Gq α subunit tagged with the TAT HIV protein sequence was introduced into an immortalized podocyte cell line by protein transduction. This stimulated inositol trisphosphate production, activated an nuclear factor of activated T cells–responsive reporter construct, and enhanced levels of both COX2 mRNA and protein compared with cells treated with a Gq protein lacking the TAT sequence. Induction of COX2 was associated with increased prostaglandin E2 production and podocyte death, both of which were attenuated by selective COX2 inhibition. In vivo, levels of COX2 mRNA and protein were significantly enhanced in podocytes from transgenic mice that expressed podocyte-targeted constitutively active Gqα compared with nontransgenic littermates. These data suggest that Gq-dependent signaling cascades stimulate calcineurin and, in turn, upregulate COX2 mRNA and protein, increase eicosanoid production, and cause podocyte injury
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