Earliest Triassic microbialites in the South China Block and other areas; controls on their growth and distribution

Earliest Triassic microbialites (ETMs) and inorganic carbonate crystal fans formed after the end-Permian mass extinction (ca. 251.4 Ma) within the basal Triassic Hindeodus parvus conodont zone. ETMs are distinguished from rarer, and more regional, subsequent Triassic microbialites. Large differences in ETMs between northern and southern areas of the South China block suggest geographic provinces, and ETMs are most abundant throughout the equatorial Tethys Ocean with further geographic variation. ETMs occur in shallow-marine shelves in a superanoxic stratified ocean and form the only widespread Phanerozoic microbialites with structures similar to those of the Cambro-Ordovician, and briefly after the latest Ordovician, Late Silurian and Late Devonian extinctions. ETMs disappeared long before the mid-Triassic biotic recovery, but it is not clear why, if they are interpreted as disaster taxa. In general, ETM occurrence suggests that microbially mediated calcification occurred where upwelled carbonate-rich anoxic waters mixed with warm aerated surface waters, forming regional dysoxia, so that extreme carbonate supersaturation and dysoxic conditions were both required for their growth. Long-term oceanic and atmospheric changes may have contributed to a trigger for ETM formation. In equatorial western Pangea, the earliest microbialites are late Early Triassic, but it is possible that ETMs could exist in western Pangea, if well-preserved earliest Triassic facies are discovered in future work

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

TSH receptor structure

When solubilized, radiolabelled membrane preparations from FRTL-5 rat thyroid cells are applied to TSH affinity columns, two separate peaks of protein can be eluted by high salts/high pH and low pH buffers, respectively. Immunoprecipitation with monoclonal antibodies to the TSH receptor shows that both peaks contain proteins related to the TSH receptor. If extracts were from cells grown without TSH, one peak has a approximately 300 K and the other a approximately 70 K protein the 70 K protein can be derived from the purified 300 K protein in vitro. A 50 and 20 K protein can be derived from the 70 K protein. If extracts are from cells grown with TSH, the peaks contain a multiplicity of additional immuno-precipitable bands of approximately 200, 175, 130, 90, 50, 20 K etc. These bands are shown to result from the ability of TSH to increase the synthesis (3-4-fold) and degradation (2-3-fold) of the 300 and 70 K proteins. The 300/70 K protein fractions are reactive with monoclonal autoimmune thyroid stimulating antibodies and contain a specific disialo ganglioside. The ganglioside migrates near GM2, i.e., like a lower order ganglioside, and contains fucose. In translation experiments, the monoclonal antibodies to the TSH receptor identify a single mRNA component which produces a protein of approximately 220 K. This protein is not present in thyroid cells which have no functional TSH receptor and which cannot be surface labelled with monoclonal antibodies to the TSH recepto