Does sea level pressure modulate the dynamic and thermodynamic forcing in the tropical Indian Ocean?

Three areas, the north Indian Ocean (NIO), the equatorial Indian Ocean (EIO) and the south Indian Ocean (SIO), were chosen over the tropical Indian Ocean to investigate the dependency of sea surface temperature (SST), wind speed (WS) and sea level pressure (SLP) on latent heat flux (LHF). The dynamic and thermodynamic behaviour of the tropical Indian Ocean was studied from the trends of the scatter represented by the mean and standard deviation of LHF, WS and humidity gradient, q s - q a, D q, binned in 1°C SST interval plotted against SST. The direct linear relationship of LHF with SST reverses at some point to display an inverse relationship when the atmosphere is coupled with the ocean. The point at which the reversal takes place marks the threshold SST which appears to have an inherent relationship with the SLP, especially when the ocean-atmosphere system is coupled. North of 5° S, the LHF peaks at the threshold SST of 27.5°C and decreases gradually on either side. The resemblance of the SST-LHF curve of SIO and EIO to that of the equatorial Pacific Ocean can be attributed to the fact that both regimes fell under the same pressure band that covers the equatorial Pacific. Shifting of LHF maxima to a lower SST regime as SLP increases is noticed at southern and northern latitudes, while such a regime shift is not noticed at the equator. This phenomenon can be attributed to relatively weaker air-sea coupling and subsequent lower LHF production at the EIO

Identification of Spt5 Target Genes in Zebrafish Development Reveals Its Dual Activity In Vivo

Spt5 is a conserved essential protein that represses or stimulates transcription elongation in vitro. Immunolocalization studies on Drosophila polytene chromosomes suggest that Spt5 is associated with many loci throughout the genome. However, little is known about the prevalence and identity of Spt5 target genes in vivo during development. Here, we identify direct target genes of Spt5 using fogsk8 zebrafish mutant, which disrupts the foggy/spt5 gene. We identified that fogsk8 and their wildtype siblings differentially express less than 5% of genes examined. These genes participate in diverse biological processes from stress response to cell fate specification. Up-regulated genes exhibit shorter overall gene length compared to all genes examined. Through chromatin immunoprecipitation in zebrafish embryos, we identified a subset of developmentally critical genes that are bound by both Spt5 and RNA polymerase II. The protein occupancy patterns on these genes are characteristic of both repressive and stimulatory elongation regulation. Together our findings establish Spt5 as a dual regulator of transcription elongation in vivo and identify a small but diverse set of target genes critically dependent on Spt5 during development