PERFORMANCE AND PERSISTENCE OF GREEN FLUORESCENT PROTEIN （gfp） MARKED AZOTOBACTER CHROOCOCCUM IN STERILIZED AND UNSTERILIZED WHEAT RHIZOSPHERIC SOIL

ThepracticaluseofAzotobacterchroococcumasbiofertilizer hasbeenincreasinglyidentifiedinrecentyears.Oftentheefficacy ofthesebacteriaisassessedonthebasisofcropresponseswithout knowingthesurvival,persistenceandcompetitiveabilityofthein troducedstrain.Inoculat…     

Fate of heavy metals and radioactive metals in gasification of sewage sludge

The fates of radioactive cadmium, strontium, cesium, cobalt, arsenic, mercury, zinc, and copper spiked into sewage sludge were determined when the sludge was gasified by a process that maximizes production of char from the sludge (ChemChar process). For the most part the metals were retained in the char product in the gasifier. Small, but measurable quantities of arsenic were mobilized by gasification and slightly more than 1% of the arsenic was detected in the effluent gas. Mercury was largely mobilized from the solids in the gasifier, but most of the mercury was retained in a filter composed of char prepared from the sludge. The small amounts of mercury leaving the gasification system were found to be associated with an aerosol product generated during gasification. The metals retained in the char product of gasification were only partially leachable with 50% concentrated nitric acid.     

Effects of host feeding and dissolved ammonium on cell division and nitrogen status of zooxanthellae in the hydroid Myrionema amboinense

There is a relationship between host feeding, nitrogen status and mitotic activity of zooxanthellae symbiotic with the marine hydroid Myrionema amboinense. Decreases in the mitotic index of zooxanthellae in starved M. amboinense, and in internal pool sizes of glutamine and glutamate, amino acids involved in ammonium assimilation via the glutamine synthetase-glutamate synthase (GS/GOGAT) pathway, were partially restored by addition of ammonium chloride to seawater in which hydroids were incubated. Levels of glutamine were more sensitive to host starvation than levels of glutamate, resulting in a decrease in the glutamine: glutamate molar ratio to that found in zooxanthellae cultured on nitrate. Hydroids starved for 5 d and then incubated in different concentrations of ammonium chloride showed a positive correlation between ammonium concentration and mitotic index of their symbiotic zooxanthellae. Host starvation caused a decrease in perturbation of levels of glutamine and glutamate during ammonium assimilation, as well as decreases in rates of assimilation of [¹⁴C]-leucine into TCA-insoluble protein, and in photosynthetic incorporation of [¹⁴C]-bicarbonate. These observations suggest that host starvation reduces nitrogen supply to the zooxanthellae, causing nitrogen stress to the symbionts and reduction in metabolic processes associated with nitrogen assimilation and photosynthesis as well as with cell division.     

Effect of diel photoperiod on nitrogen metabolism of cultured and symbiotic zooxanthellae

Ammonium uptake and assimilation by zooxanthellae (Symbiodinium sp.) cultured with an excess of nitrate was enhanced in light. Uptake was decreased by the same amount when zooxanthellae were incubated in darkness either after 6 h pretreatment in light, or at the end of the dark period of a 12 h light: 12 h dark cycle. This suggested that short-term incubations of zooxanthellae were valid tests for light enhancement of dissolved inorganic nitrogen (DIN) uptake. Assimilation of ammonium into glutamine (Gln) and glutamate (Glu) was also decreased in darkness. During a 12 h light: 12 h dark cycle, free pools of both Gln and Glu fell quickly at the start of the light period, followed by steady increases until the beginning of the next dark period. Of the four other major components of free amino acid pools tested, only the nonprotein amino acid taurine showed diel fluctuations. Gln and Glu pools in zooxanthellae freshly isolated from reef-forming corals also showed differences between day and night, suggesting changes in patterns of DIN assimilation over the diurnal cycle.     

Fly ash bricks development using concrete waste debris and self-healing bacteria

Journal of Material Cycles and Waste Management - In this study, an effort has been made to use concrete waste debris for the manufacturing of fly ash bricks as a sustainable material. Though in...