Inorganic nitrogen is an essential nutrient for photosynthetic organisms. Its efficient use in nature involves adaptation of the organisms to the availability of the nitrogen supply, to changing environmental conditions, and to the provision of carbon and other nutrients. The unicellular alga Chlamydomonas provides a useful model to identify not only each of the components participating in the ...

of heterocyclic nitrogen compounds in crude petroleum oil, were screened under microaerobic conditions, i.e. "itrogen gas substituted conditions. Eight bacteria were isolated and identified. For example, BaeiUus sp. KUKK-4 degraded 31Yk of CA when cultivated for 28 days in a mediurn initially containing CA at 1000mgll rvith shaking under the microaeroblc cond;tions. Teflon-scaled 100-rn1 tcst t...

A flow injection method for the determination of readily assimilable nitrogen (r.a.n.), i.e. ammonium and aminated nitrogen, is reported. The difference in pH of the sample in the presence and absence of formaldehyde, which blocks the amino function, provides the value of r.a.n. by monitoring the changes in absorbance of bromothymol blue at 616 nm. The detection and quantification limits are 10...

ABSTRACT A series of novel phenylsulfonyl- and 4-aminophenylsulfonyl-carboximidamides were synthesized by condensation of sulfonamides with heterocyclic methyl carbimidates obtained from heterocyclic carbonitriles and used 'at its inception.' The molecular structure of the obtained compounds is discussed. Compounds possessing heterocyclic systems with a nitrogen atom in the α position to the fu...

I. By supplying serradella nodules with a pulse of tracer 15N 2, and observing the rate of displacement of excess ~N from certain nitrogen compounds, the role of these compounds in symbiotic nitrogen fixation has been examined. 2. The labelling patterns obtained support the primary position of ammonia as a stable intermediate, and indicate that glutamic acid plus glutamine are the primary amino...

A systematic study of sensitil'ilY enhancement in ' ~N NMR spectra of phosphorus-nilrogf'o compounds by 3IP.I5N polariSlllion tfllrtsff'r \'l as .,..rformed !ISing Iris-(dimethylamioo)phosphine ( I) as a model compound. The application of sen!ral mul1ipulse lechoiques (refocussed and oon-rdocussed INEPT. DEPT) lind dccoupling sclw>mes shows lh:tl muimum enhaocement \'I'as reached \'lith fhe non...

Snow and ice play their most important role in the nitrogen cycle as a barrier to land-atmosphere and ocean-atmosphere exchanges that would otherwise occur. The inventory of nitrogen compounds in the polar ice sheets is approximately 260 Tg N, dominated by nitrate in the much larger Antarctic ice sheet. Ice cores help to inform us about the natural variability of the nitrogen cycle at global an...

The photophysics and photochemistry of the nitrogen-rich compounds diazomethane and diazirine were studied both experimentally and theoretically following excitation in the ultraviolet. These molecules are locally stable on their ground potential energy surfaces, but they contain large amounts of nuclear potential energy that can be unleashed upon photoexcitation. Methods for generating these c...

The paper is a short review on nitrogen compounds removal, as ammonia, nitrate, nitrite, from municipal waste water, containing primary information of nitrogen chemistry, consideration on the physical-chemistry methods of removal and also on the most popular wastewater nitrification systems[1].