Introduction Conclusions References

background: quaternary ammonium compounds (qac), which contain benzalkonium chloride as the most widely used agent, are employed as wound and skin antiseptics, as well as disinfectants in hospitals. the resistance mechanism to disinfectants is usually determine by genes which are related to resistance to quaternary ammonium compounds, namely, qace, qacδe1, qacδe1 that are found in gram-negative...

the microalgae, dunaliella salina was isolated from maharlu salt lake, south east of shiraz, iran. the isolated strain was identified by both morphological and physiological markers. the complete its region (its1 + its2) including the 5.8s rdna gene used as molecular marker confirmed our identification. growth and cell proliferation, total chlorophyll and carotenoid contents were determined in ...

Nitrogen metabolism of planktonic populations in coastal waters of the southern Scotia Sea was studied in February-March 1981 aboard R/V M e l d l e . In spite of the high concentration of nitrate present in these waters (21 to 29 FM), up to 93 % of phytoplankton nitrogen was assimilated in the form of ammonium, with the overall mean being 78 %. Time course experiments showed that uptake of nit...

Ammonium uptake in plant roots is mediated by AMT/MEP/Rh-type ammonium transporters. Out of five AMTs being expressed in Arabidopsis roots, four AMT1-type transporters contribute to ammonium uptake, whereas no physiological function has so far been assigned to the only homolog belonging to the MEP subfamily, AMT2;1. Based on the observation that under ammonium supply, the transcript levels of A...

The brain ammonium production is detoxified by astrocytes, the gut ammonium production is detoxified by hepatic cells, and the renal ammonium production plays a major role in renal acid excretion. As a result of ammonium handling in these organs, the ammonium and pH values are strictly regulated in plasma. Up until recently, it was accepted that mammalian cell transmembrane ammonium transport w...

In developing leaves of Pisum sativum the levels of ammonium did not change during the light-dark photoperiod even though asparaginase (EC 3.5.1.1) did; asparaginase activity in detached leaves doubled during the first 2.5 hours in the light. When these leaves were supplied with 1 millimolar methionine sulfoximine (MSX, an inhibitor of glutamine synthetase, GS, activity) at the beginning of the...

the effect of salinity on organic removal and ammonium oxidation in a down-flow hanging sponge reactor was investigated by conducting a long-term continuous experiment over a period of 800 days. the dhs reactor, constructed by connecting three identical units, was fed with artificial wastewater containing 500 mg-n/l of ammonium nitrogen and 1400 mg- cod/l of phenol. salinity of the influent wa...

ammonium ions wastewater pollution has become one of the most serious environmental problems today. the treatment of ammonium ions is a special concern due to their recalcitrance and persistence in the environment. in recent years, various methods for ammonium ion removal from wastewater have been extensively studied. this paper reviews the current methods that have been used to treat ammonium ...