Solution Structure of Tensin2 SH2 Domain and Its Phosphotyrosine-Independent Interaction with DLC-1

Background: Src homology 2 (SH2) domain is a conserved module involved in various biological processes. Tensin family member was reported to be involved in tumor suppression by interacting with DLC-1 (deleted-in-liver-cancer-1) via its SH2 domain. We explore here the important questions that what the structure of tensin2 SH2 domain is, and how it binds to DLC-1, which might reveal a novel binding mode. Principal Findings: Tensin2 SH2 domain adopts a conserved SH2 fold that mainly consists of five b-strands flanked by two a-helices. Most SH2 domains recognize phosphorylated ligands specifically. However, tensin2 SH2 domain was identified to interact with nonphosphorylated ligand (DLC-1) as well as phosphorylated ligand. Conclusions: We determined the solution structure of tensin2 SH2 domain using NMR spectroscopy, and revealed the interactions between tensin2 SH2 domain and its ligands in a phosphotyrosine-independent manner

Comparative study on bioaccumulation of lead and cadmium by the cyanobacterium Synechocystis sp. PCC 6803 under laboratory conditions

Bioremoval techniques have been employed in cleaning water bodies that suffer from detrimental effects of heavy metal pollution. In the present laboratory study, bioaccumulation of Pb2+ and Cd2+ was assessed using the unicellular cyanobacterium Synechocystis sp. PCC 6803, a model organism widely used in genetic, physiological and morphological studies. Growth was measured as cell counts and showed that Pb2+, at low exposure concentrations (0.5 and 1 µg mL–1), had a positive influence on Synechocystis sp. PCC 6803, resulting in slight growth stimulations; however, the species could not withstand long periods of exposure to both metals at higher concentrations (2, 4, 6 and 8 µg mL–1). The highest inhibitions (53.14% and 70.07% for Pb2+ and Cd2+, respectively, at 8 µg mL–1) were recorded after six days. Rapid metal removal was observed during the first two days of incubation, followed by a gradual reduction. Though the differences in accumulated amounts seemed to be narrow, the percentage of Pb2+ removed from the solution was always higher than that of Cd2+ in all the treatments. Accumulated amounts increased in a dose-dependent manner for both metals. The maximum accumulations (155.63 and 199.83 mg g–1 dry weight for Pb2+ and Cd2+, respectively) were recorded at the end of six days. The species can be considered a good accumulator of metals, with high bioconcentration factor values of 20 657 and 24 980 for Pb2+ and Cd2+, respectively

How Does Lead (Pb 2+ ) at Low Concentrations Affect on Spirulina (Arthrospira) platensis

ABSTRACT Spirulina (Arthrospira) platensis, a blue-green photoautotrophic alga has widely been used for the production of high valued protein for human and animal feeding as well. The present study focused on bioaccumulation of Pb 2+ and its effects on growth of S. platensis. , at 2 days of incubation) and decreased as incubation progressed. Bioconcentration factor (BCF) also reached to the peak (1218, 1127, 888, 928 and 1035 for 1, 2, 3, 4 and 5 µg/mL of Pb 2+ respectively) at 2 days of incubation followed by a gradual reduction. No marked differences were found in growth measured as optical density at 560 nm. It could therefore be concluded that no remarkable inhibition on growth of S. platensis is shown when cultured in contaminated water with low concentrations of Pb 2+ . Furthermore, the species sounds potential accumulator of Pb 2+ and thus could be used in detoxifying heavy metal affected aquatic ecosystems