Proterozoic Charnockites at 1.6 & 1.0 Ga in the Eastern Ghats Belt, India, Mirror Secular Evolution of Continental Crust

As the Earth continued to cool down, the chemistry of granitic rocks reflect the changing conditions &/or processes of continental crust formation. Compared to the 1.0 Ga charnockites, the 1.0 Ga charnockites in the Eastern Ghats Belt, are more potassium and Rubidium rich, with more negative Eu anomalies and show much less HREE fractionation. Thus the 1.0 Ga charnockites are more evolved in composition and this is consistent with secular evolution of the continental crust throughout the Proterozoic era

Plasmid Encoded AcrAB–TolC Tripartite Multidrug-Efflux System in Acidiphilium symbioticum H8

Acidophilic bacterium, Acidiphilium symbioticum H8, is resistant to high levels of several heavy metals, hydrophobic agents, and organic solvents. The *9.6 kb plasmid pASH8, was purified, digested with HindIII, and sub-cloned in pUC19 at the respective site. Three different fragment size clones were achieved. The clones were completely sequenced and analyzed. The first clone encodes for a single putative open reading frame (ORF), which showed significant homology to several rusticyaninA1 proteins. The second clone encodes for a 43-kDa protein, which has conserved domain homology with several outer envelop TolC proteins. The clone with pASH8 tolC gene can functionally complement an Escherichia coli tolC mutant strain, making it resistant to several toxic hydrophobic agents, earlier for which it was sensitive. The tolC gene was found to be essential for imparting resistance to the clone toward these toxic hydrophobic agents. The third clone encodes for a putative 318-aa AcrA (acriflavine resistance protein A) protein and the clone was resistance to plasmid curing dye acriflavine. The clone also has a truncated ORF, which showed significant homology to cation-efflux pump AcrB. This study is the first to report a multi-drug efflux system to be encoded on a plasmid of any Acidiphilium strain

Sequence-Selective Binding of Phenazinium Dyes Phenosafranin and Safranin O to Guanine-Cytosine Deoxyribopolynucleotides: Spectroscopic and Thermodynamic Studies

The sequence selectivity of the DNA binding of the phenazinium dyes phenosafranin and safranin O have been investigated with four sequence-specific deoxyribopolynucleotides from spectroscopic and calorimetric studies. The alternating guanine-cytosine sequence selectivity of the dyes has been revealed from binding affinity values, circular dichroism, thermal melting, competition dialysis, and calorimetric results. The binding affinities of both the dyes to the polynucleotides were of the order of 105 M-1, but the values were higher for the guanine-cytosine polynucleotides over adenine-thymine ones. Phenosafranin had a higher binding affinity compared to safranin O. Isothermal titration calorimetric studies revealed that the binding reactions were exothermic and favored by negative enthalpy and predominantly large positive entropy contributions in all cases except poly(dA) · poly(dT) where the profile was anomalous. Although charged, nonpolyelectrolytic contribution was revealed to be dominant to the free energy of binding. The negative heat capacity values obtained from the temperature dependence of enthalpy changes, which were higher for phenosafranin compared to safranin O, suggested significant hydrophobic contribution to the binding process. In aggregate, the data presents evidence for the alternating guanine-cytosine base pair selectivity of these phenazinium dyes and a stronger binding of phenosafranin over safranin O