Effect Of NH Research Articles

Sulfur Uptake by Corn as Influenced by Ammonium and Nitrate Nitrogen

AbstractThe effect of NH4 and NO3 ions on S uptake by corn (Zea mays L.) from a starter fertilizer was studied with the use of 15N and 35S. When both the N and S were applied as a starter, the uptake of fertilizer S was significantly increased when NH4 instead of NO3 was used as the N source. This effect was observed in young plants through 4 weeks of age. More N was absorbed by the corn plant when NH4 rather than NO3 was supplied as the N source. The N source, however, had no significant effect on the total S, SO4‐S or total N content of the tissue and the corn yield.

Porphyrin biosynthesis: VI. Separation and purification of porphobilinogen deaminase and uroporphyrinogen isomerase from cow liver. Porphobilinogenase an allosteric enzyme

1. 1.|Porphobilinogenase has been isolated and purified from cow liver and its components, porphobilinogen deaminase and uroporphyrinogen isomerase, have been separated from each other and purified. 2. 2.|The effect of NH 4 + was studied. The deaminase exhibited classical Michaelis-Menten kinetics in the absence or presence of NH 4 +, which at high concentrations behaved as a noncompetitive inhibitor of the deaminase. As expected from Hill plots, n = 1 both in the absence or presence of NH 4 +. Instead, when activity of porpho bilinogenase is plotted versus porphobilinogen concentration, sigmoid curves are obtained; but the presence of NH 4 + at different concentrations altered the kinetic parameters of this enzymic system, again showing normal kinetics. In addition, n values were found to be 2 for porphobilinogen per porphobilinogenase molecule and 1 in the presence of NH 4 + which behaves as a competitive inhibitor of the isomerase. Results are discussed in relation to the allosteric theories of monod et al. 1,2 and liver porphobilinogenase is proposed to be an allosteric protein. 3. 3.|The presence of an ultrafiltrable factor which stimulates uroporphyrinogen formation from porphobilinogen has been revealed.

The porphobilinogen deamise - uroporphyrinogen III cosynthetase system (porphobilinogenase) from bovine liver. Kinetic studies

The conversion of prophobilinogen (PBG) into uroporphyrinogens is enzymically catalysed by the porphobilinogenase enzyme system which is widely distributed [l-lo]. In plant tissue extracts [ 1 l] the formation of uroporphyrinogen I from PBG is brought about by PBG deaminase (Uroporphyri- nogen I synthetase); in the presence of both PBG de- aminase and uroporphyrinogen III cosynthetase (iso- merase) uroporphyrinogen III, the physiological in- termediate in haem biosynthesis, is formed. Here we report kinetic studies using purified PBG deaminase and porphobihnogenase. The effects of NH: ion con- centrations on the type of uroporphyrinogen formed are also reported. The results indicate that bovine liver porphobilinogenase shows cooperative effects. 2.

Comparison of two optimizations of a nonlinear boundary-value problem.

The effect of NH and NRe on the fluid temperature during a transient varies greatly depending on their initial and steadystate values. In some cases, such as those shown in Figs. 2b and 2c, the peak transient temperature can be an order of magnitude greater than the initial or steady-state value, whereas in others, such as those shown in Fig. 4, the effect may be quite small. Since unsteady fluid temperatures may substantially differ from the steady-state values, precautions may have to be taken in the operation of some MHD devices to prevent overheating during a transient such as a startup.

Permeability of alkali metal cations in lobster muscle. A comparison of electrophysiological and osmometric analyses.

Single muscle fibers from lobster walking legs are effectively impermeable to Na, but are permeable to K. They shrink in hyperosmotic NaCl; they swell in low NaCl media which are hyposmotic or which are made isosmotic with the addition of KCl. In conformity, the membrane potential is relatively insensitive to changes in external Na, while it responds according to the Nernst relation for changes in external K. When the medium is made isosmotic or hyperosmotic with RbCl the volume and membrane potential changes are of essentially the same magnitudes as those in media enriched with KCl. The time courses for attaining equilibrium are slower, indicating that Rb is less permeant than K. Substitution of CsCl for NaCl (isosmotic condition) produces no change in volume of the muscle fiber. Addition of CsCl (hyperosmotic condition) causes a shrinkage which attains a steady state, as is the case in hyperosmotic NaCl. Osmotically, therefore, Cs appears to be no more permeant than is Na. However, the membrane depolarizes slowly in Cs-enriched media and eventually comes to behave as an ideal Cs electrode. Thus, the electrode properties of the lobster muscle fiber membrane may not depend upon the diffusional relations of the membrane and ions, and the osmotic permeability of the membrane for a given cation may not correspond with the electrophysiologically deduced permeability. Comparative data on the effects of NH(4) and Li are also included and indicate several other degrees of complexity in the cell membrane.

Attached Growth of Sphaerotilus and Mixed Populations in a Continuous-flow Apparatus1

The effects of NH(4)Cl concentration, organic nitrogen compounds, glucose concentration, dissolved oxygen concentration, and flow rate on the attached growth of pure cultures of Sphaerotilus natans and of a mixed population in a continuous-flow apparatus are described. Low concentrations of NH(4)Cl and oxygen, and high flow rates resulted in attached populations that were dominated by Sphaerotilus. The conditions that allowed maximal attached growth in pure culture did not correspond to the conditions that promoted attached growth of Sphaerotilus in a mixed population.

Effects of NH 4+-ions on acid-base properties and ion movements in isolated frog skin

1. 1. The epidermal surface is a region of acidity, the corium a region of alkalinity. Within narrow limits the maximal spontaneous pH difference is from pH 6 to pH 8. 2. 2. In individual skins the regulation of the pH at the epidermis is remarkably precise. 3. 3. Release of acid by the epidermis can almost quantitatively be accounted for by release of respiratory CO 2. The alkalinity of the corium results from its high HCO 3 - content. 4. 4. Within the pH limits mentioned, the results do not suggest Na + ⇌ H + exchange at the epidermis. 5. 5. Skins in NH 4Cl-salt solutions show a diminished or reversed [H +] gradient. Na + outflux is increased, Na + influx, net Na + flux and skin P.D. (but not O 2 consumption) are significantly decreased. H + ions of the medium are exchanged for tissue K + in nearly equivalent amounts.

Effect of NH 3 on Deposition from Alkaline Electroless Nickel and Cobalt Plating Baths

The ammonia generally used as a buffer in alkaline electroless nickel and cobalt plating baths has been shown to have a significant effect on both the rate of deposition of thin metal films and the magnetic and physical properties of such films. These effects have been studied on both metallic and nonmetallic substrates, using both ammonia and nonammine buffer systems, and attempts have been made to correlate them with spectral and polarographic observations.

INFLUENCE OF FORM AND MODE OF NITROGEN FERTILIZER APPLICATION ON THE AVAILABILITY OF SOIL AND FERTILIZER POTASSIUM

Ammonium applied alone or after addition of K depressed the uptake of K by oats grown in a sandy loam soil in the greenhouse. When NH4 was added first and K later at seeding, however, NH4 increased K-uptake.In the absence of K fertilizer, NH4 reduced the release of non-exchangeable K to the plants. When added prior to or at the same time as K at seeding, NH4 reduced K-fixation. This inhibitory effect of NH4 on fixation of added K was reflected in higher amounts of K in solution as shown by lower [Formula: see text] ratios. These results of chemical extraction of the soil indicated that the effects of NH4 on K-uptake by the oat crop arose from reactions in the soil.

Requirement of an alkaline pH and ammonia for substrate oxidation by Bacillus pasteurii.

Wiley, W. R. (Washington State University, Pullman) and J. L. Stokes. Requirement of an alkaline pH and ammonia for substrate oxidation by Bacillus pasteurii. J. Bacteriol. 84:730-734. 1962-Resting-cell suspensions of Bacillus paseurii require a pH higher than 8.0 and also NH(4) (+) for the oxidation of glycine, alanine, serine, glutamic acid, other amino acids, and compounds of the Krebs cycle. The optimal pH is 9.2. Maximal activity was obtained with 0.5% (NH(4))(2)SO(4), the highest concentration tested. NH(4) (+) can be supplied by a number of inorganic and organic ammonium salts. The effect of NH(4) (+) is fairly specific. It cannot be replaced by Na(+), Cs(+), and Mg(++), and only partially replaced by Li(+), K(+), Rb(+), and Ca(++). Some possible metabolic functions of the required alkaline pH and NH(4) (+) are discussed.

Experimental investigation of silicate systems containing two volatile components; Part 2, The effects of NH 3 and HF, in addition to H 2 O on the melting temperatures of albite and granite

<h3>Abstract</h3> <h3>Importance</h3> The ENIGMA clinical high risk for psychosis (CHR) initiative, the largest pooled CHR-neuroimaging sample to date, aims to discover robust neurobiological markers of psychosis risk in a sample with known heterogeneous outcomes. <h3>Objective</h3> We investigated baseline structural neuroimaging differences between CHR subjects and healthy controls (HC), and between CHR participants who later developed a psychotic disorder (CHR-PS+) and those who did <i>not</i> (CHR-PS-). We assessed associations with age by group and conversion status, and similarities between the patterns of effect size maps for psychosis conversion and those found in other large-scale psychosis studies. <h3>Design, Setting, and Participants</h3> Baseline T1-weighted MRI data were pooled from 31 international sites participating in the ENIGMA CHR Working Group. MRI scans were processed using harmonized protocols and analyzed within a mega- and meta-analysis framework from January-October 2020. <h3>Main Outcome(s) and Measure(s)</h3> Measures of regional cortical thickness (CT), surface area (SA), and subcortical volumes were extracted from T1-weighted MRI scans. Independent variables were group (CHR, HC) and conversion status (CHR-PS+, CHR-PS-, HC). <h3>Results</h3> The final dataset consisted of 3,169 participants (CHR=1,792, HC=1,377, age range: 9.5 to 39.8 years, 45% female). Using longitudinal clinical information, we identified CHR-PS+ (N=253) and CHR-PS- (N=1,234). CHR exhibited widespread thinner cortex compared to HC (average <i>d</i>=-0.125, range: -0.09 to -0.17), but not SA or subcortical volume. Thinner cortex in the fusiform, superior temporal, and paracentral regions was associated with psychosis conversion (average <i>d</i>=-0.22). Age showed a stronger negative association with left fusiform and left paracentral CT in HC, compared to CHR-PS+. Regional CT psychosis conversion effect sizes resembled patterns of CT alterations observed in other ENIGMA studies of psychosis. <h3>Conclusions and Relevance</h3> We provide evidence for widespread subtle CT reductions in CHR. The pattern of regions displaying greater CT alterations in CHR-PS+ were similar to those reported in other large-scale investigations of psychosis. Additionally, a subset of these regions displayed abnormal age associations. Widespread CT disruptions coupled with abnormal age associations in CHR may point to disruptions in postnatal brain developmental processes. <h3>Key Points</h3> <h3>Question</h3> How do baseline brain morphometric features relate to later psychosis conversion in individuals at clinical high risk (CHR)? <h3>Findings</h3> In the largest coordinated international analysis to date, reduced baseline cortical thickness, but not cortical surface area or subcortical volume, was more pronounced in CHR, in a manner highly consistent with thinner cortex in established psychosis. Regions that displayed greater cortical thinning in future psychosis converters additionally displayed abnormal associations with age. <h3>Meaning</h3> CHR status and later transition to psychosis is robustly associated with reduced cortical thickness. Abnormal age associations and specificity to cortical thickness may point to aberrant postnatal brain development in CHR, including pruning and myelination.

Experimental Investigation of Silicate Systems Containing Two Volatile Components; Part 2, the Effects of NH 3 and HF, in Addition to H 2 O on the Melting Temperatures of Albite and Granite

Addition of NH 3 to water-albite and water-granite mixtures at constant pressure raises the melting temperatures of albite and granite, whereas addition of HF to these mixtures causes marked lowering of melting temperatures. Results obtained at 2,750 bars pressure for charges containing 1:1 weight ratio of silicate to total volatiles are presented as perspective TX projections from within isobaric prisms onto the volatile faces of the prisms. In the presence of H 2 O alone at 2,750 bars pressure, albite melts between 795 degrees C. and 810 degrees C., and granite begins to melt at 670 degrees C.; in the presence of 8.2 weight percent NH 3 solution, the melting interval of albite is 805 degrees C. to 825 degrees C., and granite begins to melt at 690 degrees C.; in the presence of 8 weight percent HF solution, the melting interval of albite is 610 degrees C. to 685 degrees C., and granite begins to melt at 595 degrees C. No chemical reaction was detected in systems containing NH 3 , but considerable reaction occurs with HF. With increasing HF concentration in the system NaAlSi 3 O 8 -H 2 O-HF, quartz becomes a stable phase and the system is no longer ternary. In the presence of HF solutions, albite crystals grow much larger than in the presence of H 2 O alone.

Fibrillation of muscle fibers produced by ammonium ions and its relation to the spontaneous activity at the neuromuscular junction.

1. Effects of NH4+on the isolated muscle of frog and toad were studied. Chiefly, sartorius muscle was used. When the muscle is immersed in NH4+ Ringer, discharge frequency of miniature e.p.p. increases very much and at the same time fibrillations of muscle fibers are produced. Effects of NH4+ appears with a delay.2. Fibrillations due to NH4+is completely suppressed by tubocurarine and can not be suppressed by tetrodotoxin. It is concluded that the augmentation of discharge frequency of miniature e.p.p. is the cause of the fibrillation.3. Fibrillation from this origin can not be produced by K+, though discharge frequency is increased by K+. Possible causes of the difference were discussed.

The Effects of NH_4-N or NO_3-N Supplied as Nitrogen Source on the Root Development of Luffa cylindrica, Roehm

The Effects of NH_4-N or NO_3-N Supplied as Nitrogen Source on the Root Development of Luffa cylindrica, Roehm