RESUMO
In order to understand the phytoplankton community structure and its relationship with the environmental variables in the near shore waters of Kalpakkam, east coast of India, observations were carried out during 2008-2009. Phytoplankton population was comprised of 219 species, and the density was higher during the southwest monsoon (SWM) and inter-monsoon seasons than that of north east monsoon (NEM) season. The nutrient status on a temporal and spatial scale indicated the impact of point sources carrying anthropogenic runoff. Comparison of ambient nutrient ratios with the Redfield ratio (N/P/Si = 16:1:16) showed a clear temporal variation in the factors that regulate the phytoplankton growth. SWM and inter-monsoon season was evident to have an acute N-limitation of algal growth (~76%) whereas P-limitation was encountered during the NEM season (~75%). Interestingly, a sizable population of cyanobacteria (Trichodesmium erythraeum) were noticed during NEM season when there was an exponential increase in nitrogen concentration, probably due to nitrogen fixation. No significant impact of temperature on phytoplankton proliferation was observed in situ during the study period.
Assuntos
Baías/química , Monitoramento Ambiental , Fixação de Nitrogênio , Fitoplâncton/crescimento & desenvolvimento , Baías/microbiologia , Cianobactérias/classificação , Cianobactérias/crescimento & desenvolvimento , Índia , Fitoplâncton/classificação , Estações do AnoRESUMO
Profilin is a cytoskeletal protein that interacts specifically with actin, phosphoinositides and poly (l-proline). Experimental results and in silico studies revealed that profilin exists as dimer and tetramer. Profilin oligomers possess weak affinity to poly (l-proline) due to unavailability of binding sites in dimers and tetramers. Phosphorylation studies indicate that profilin dimers are not phosphorylated while teramers are preferentially phosphorylated over monomers. In silico studies revealed that PKC phosphorylation site, S137 is buried in dimer while it is accessible in tetramer.
Assuntos
Peptídeos/metabolismo , Profilinas/química , Profilinas/metabolismo , Sequência de Aminoácidos , Animais , Autorradiografia , Western Blotting , Bovinos , Cromatografia , Misturas Complexas , Modelos Moleculares , Dados de Sequência Molecular , Fosforilação , Profilinas/imunologia , Ligação Proteica , Estrutura Quaternária de Proteína , Estrutura Secundária de Proteína , Alinhamento de Sequência , SolventesRESUMO
Synthesis of mixed imine-amine pyrrolobenzodiazepine (PBD) dimers that are comprised of DC-81 and secondary amine (N10) of DC-81 subunits tethered to their C8 positions through alkanedioxy linkers (comprised of three and five carbons) is described. These noncross-linking unsymmetrical molecules exhibit significant DNA minor groove binding ability and one of them 5b linked through the pentanedioxy chain exhibits efficient DNA binding ability (DeltaTm=11.0 degrees C) when compared to naturally occurring DC-81, 1 (DeltaTm=0.7 degrees C). The imine-amine PBD dimers exhibit promising in vitro antitumor activity in a number of human cancer cell lines.