-Existing methods of measuring atmospheric aerosol strong acidity adequately prevent neutralization of fine-particle acidity by removing coarse alkaline particles and gaseous ammonia from air samples. However, these techniques do not consider particle interactions on the collection medium; therefore, they may still underestimate the actual aerosol acidity. Assessment of acid neutralization due ...

The removal of excess nutrients from water ecosystems requires oxidation of toxic ammonium by two types of bacteria; one oxidizes ammonium to nitrite and the other oxidizes nitrite to nitrate. The oxidation of ammonium is often incomplete and nitrite accumulates. Nitrite is also toxic, and is converted by the ammoniumoxidizing bacteria to nitrous oxide, a powerful greenhouse gas. Here we use ma...

A simple analytical method was developed to measure concentrations of glufosinate ammonium and its metabolites, 3-methylphosphinico-propionic acid (MPP) and 2-methylphosphinico-acetic acid (MPA), in field soil samples. To determine the minimum quantification limit, samples were spiked at different levels (0.1, 0.5, and 1.0 mg/kg). Soil samples were extracted with ammonium hydroxide solution 5% ...

KAYMAK, H. C., 2013. Effect of nitrogen forms on growth, yield and nitrate accumulation of cultivated purslane (portulaca oleracea l.). Bulg. J. Agric. Sci., 19: 444-449 The present investigation was carried out to determine not only the most appropriate nitrogen form but also the effect of these forms on growth, yield, element content and nitrate accumulation of cultivated purslane (portulaca ...

Root development is strongly affected by the plant's nutritional status and the external availability of nutrients. Employing split-root systems, we show here that local ammonium supply to Arabidopsis thaliana plants increases lateral root initiation and higher-order lateral root branching, whereas the elongation of lateral roots is stimulated mainly by nitrate. Ammonium-stimulated lateral root...

A newly discovered process by which ammonium is converted to dinitrogen gas under anaerobic conditions (the Anammox process) has now been examined in detail. In order to confirm the biological nature of this process, anaerobic batch culture experiments were used. All of the ammonium provided in the medium was oxidized within 9 days. In control experiments with autoclaved or raw wastewater, with...

Quaternary ammonium compounds are an important class of molecules with wide variety of applications, mainly in the antimicrobial field. Quaternary ammonium compounds have the ability to bind with the anionic moiety of phospholipids of the bacterial membrane, disrupting the cell membrane of the microorganisms. However, classical quaternary ammonium salts can have adverse effects on the environme...

In cyanobacteria, the transcriptional activator NtcA is involved in global nitrogen control and, in the absence of ammonium, regulates the expression of genes involved in the assimilation of alternative nitrogen sources. The oceanic picocyanobacterium Synechococcus sp. strain WH 8103 harbors a copy of ntcA, but in the present study, we show that unlike other marine cyanobacteria that have been ...