The substrate specificity of beef heart phosphodiesterase activity and of the phosphodiesterase activity at the cell surface of the cellular slime mold Dictyostelium discoideum has been investigated by measuring the apparent Km and maximal velocity (V) of 24 derivatives of adenosine 3',5'-monophosphate (cAMP). Several analogs have increased Km values, but unaltered V values if compared to cAMP;...

Organisms limited by carbon, nitrogen or sulphur can reduce protein production costs by transitions to less costly amino acids, or by reducing protein expression. These alternative mechanisms of nutrient thrift might respond differently to selection, but this possibility remains untested. We hypothesized that relatively invariant sequence composition responds to long-term variation in nutrient ...

Sulphur-containing amino acids (i.e. Cysteine (Cys) and methionine (Met)) constitute an important proportion of the soil organic sulphur. However, detailed information regarding microbial transformation Cys Met at a molecular level remain poorly characterized. To trace fate carbon (C) sulphur (S) derived from in agricultural grassland soil, a14C 35S dual-isotopic labelling approach was adopted....

in this investigation, the performance of a tower for absorption of sulphur dioxide gas into calcium carbonate solution has been studied. the trays had no downcomer and the tower itself was a scaled down pilot from industrial equipment. the industrial scale tower was used for clean up of 110000 m3/hr gas using 40 m3/hr alkaline solution. the study was composed of two parts. in the first section...

An efficient method was employed for the ash and pyrite sulphur removal from bitumen using column flotation process. The bitumen samples containing 9.6% sulphur (6.81% in the pyrite sulphur form) and 26.4% ash were successfully showed up to 75.20% of pyrite sulphur (e.g.; 51.66% of total sulphur) and 70.81% of ash removal. The Box-Behnken Design (BBD) was employed to design the experiments, to ...