The influence of phosphorus and nitrogen on millet and clover growing in soils affected by salinity

Summary The growth of foxtail millet and clover in soils of varying degrees of salinity (0.5 to 13 mmhos/cm), treated with nitrogen and phosphorus, was studied. Salinity levels were achieved by addition of sodium chloride. Nitrogen (10 to 60 ppm N) and phosphorus (6.4 to 44.8 ppm P) were added as NH₄NO₃ and H₃PO₄, respectively. The growth of millet decreased sharply with increase in soil salinity, when N-P treatments were not applied. The development of this plant altered under saline conditions, however, when nitrogen and phosphorus were added; various N-P combinations affected plant growth in saline soil differently. Phosphorus, when applied at relatively high rates, significantly improved plant growth. Increased rates of nitrogen in the N-P treatments generally had no significant effect on growth; it was reduced when the N/P ration was highest. Clover ceased to grow when the salinity of the soil exceeded 7 mmhos/cm and no N-P was added. Phosphorus enhanced the growth of clover, and at high rates of its application in the N-P combinations, clover grew even at the highest salinity level tested (13 mmhos/cm). Nitrogen increase had no marked effect on plant development. Comparing enhancement of growth at high salinity levels, clover was somewhat less affected by the N-P treatment than millet. The top/root ratio of clover generally increased with increase of phosphorus in the N-P combinations. This research (Parts I and II) was supported in part by a grant from the U.S. Department of Agriculture under P. L. 480.     

The Crystal and Molecular Structure of 5-Fluoro-2′-Deoxy-β-Uridine

The crystal structure of 5-fluoro-2′-deoxy-β-uridine (FUDR) has been solved and the details of the molecular structure determined by x-ray analysis. The bond lengths and angles have been measured and are compared with the dimensions found for calcium thymidylate and adenylic acid. In all three compounds the bonds formed by the nitrogen atom involved in the glycosidic bond are not coplanar. Furthermore, it is found that in FUDR the C2′ carbon atom is out of the plane of the ribose ring. The possible effect of these observations on nucleic acid structures is discussed.     

反硝化除磷戈登氏菌属的富集及其菌剂制备

【背景】投加微生物菌剂是强化生物处理效能的重要手段,反硝化是污水脱氮除磷的关键步骤,但目前对于反硝化微生物菌剂相关的研究报道较少。【目的】驯化高效反硝化聚磷菌菌剂,并对系统进行生物强化。【方法】采用两阶段法快速富集反硝化聚磷菌,筛选高效脱氮除磷功能菌株NC1-1并进行鉴定,以NC1-1为菌种来源制备干粉菌剂,研究菌剂强化A²SBR系统污水处理效果。【结果】历经36 d后反硝化聚磷菌富集成功,菌株NC1-1经鉴定属于戈登氏菌属,其脱氮除磷率分别为89.46%和91.68%。麦麸、玉米粉配比为85%:15%、NC1-1投菌量为20 mL、发酵液用量20 mL的条件下成功制得干粉菌剂,干粉菌剂最佳投加量为10%的A²SBR系统总磷（total phosphorus,TP）和NO₃^--N去除率比未投加菌剂的A²SBR系统提高12.06%和11.52%。【结论】菌剂NC1-1的投加使A²SBR系统的污染物去除效能进一步提高,研究结果为进一步研究反硝化聚磷菌菌剂提供了...     

The x ray structure of thiazolidine-4-carboxylic acid

The X ray crystal structure of thiazolidine-4-carboxylic acid has been determined. It appears that the anomalously low basicity of this compound in comparison with that of its non-sulfur-containing analogue, proline, is due to the resonance stabilization of the unprotonated form of thiazolidine-4-carboxylic acid. This stabilization is conferred through an increased interaction of the sulfur atom with the thiazolidine-4-carboxylic acid ring that is only possible when the nitrogen atom maintains a trigonal geometry. This effect seems also to account for the greater instability of N-hydroxymethylamines formed from thiazolidine-4-carboxylic acid as compared to those formed from proline. The crystal structure shows, in addition, an intramolecular hydrogen bond in combination with a bifurcated hydrogen bond.     

Physical studies on phosphonium phosphatidylcholine. A unique [31P]phosphorus nuclear-magnetic-resonance probe for model and biological membranes.

1. Distearoyl phosphatidylcholine and the phosphonium analogue, in which the nitrogen atom is replaced by phosphorus, show similar gel-liquid crystalline transition temperatures as detected by differential scanning calorimetry. 2. The temperature-dependence of the 31P n.m.r. (nuclear-magnetic-resonance) linewidths of the phosphate resonances of sonicated vesicles of distearoyl phosphatidylcholine and the phosphonium analogue are similar. Below the phase-transition temperature the linewidths decrease as the temperature is raised. Above the phase-transition temperature the phosphate resonances are relatively temperature-independent. The phosphonium 31P n.m.r. signal exhibits the same pattern of temperature-dependence. 3. The 31P n.m.r. phosphonium resonance is sensitive to the paramagnetic shift reagent, K3Fe(CN)6. Use of K3Fe(CN)6, together with Nd(NO3)3, enabled the determination of the trans-bilayer distribution of egg-yolk phosphatidylcholine and its phosphonium analogue in co-sonicated vesicles. Both are distributed comparably across the bilayer of the vesicles. 4. The phosphonium 31P n.m.r. signal is much sharper than the corresponding phosphate resonance in both sonicated and unsonicated dispersions of the phosphatidylcholine analogue. 5. The properties of the phosphonium analogue of phosphatidylcholine are discussed in terms of its suitability as a probe of membrane structure.     

Ab initio and DFT study of the inner mechanism and dynamic stereochemistry of electrophilic addition reaction of bromine to bisbenzotetracyclo[6.2.2.23,6.02,7]tetradeca-4,9,11,13-tetraene

The inner mechanism and dynamic stereochemistry of electrophilic addition of bromine to bisbenzotetracyclo[6.2.2.2(3,6).0(2,7)]tetradeca-4,9,11,13-tetraene(BBTT) molecule have been investigated by the methods of quantum chemistry. The structure of the BBTT molecule has been studied by ab initio and DFT/B3LYP methods using the 6-31G(d) and 6-311G(d) basis sets. The double bonds of BBTT molecule are endo-pyramidalized. The structure and stability of the cationic intermediates and products of the addition reaction have been investigated by HF/6-311G(d), HF/6-311G(d,p), B3LYP/6-311G(d) and B3LYP/6-311++G(2d,p)//B3LYP/6-311G(d) methods. The bridged bromonium cation isomerized into the more stable nonclassical delocalized N- and U-type cations and the difference between the stability of these cations is small. For the determination of the direction of addition reaction and the stereochemistry of the products, the stability of nonclassical delocalized N- and U-type ions and the structure of their cationic centres play a vital role. Since the cationic centre of the N-type ion is in interaction with the benzene ring from the exo face, the nucleofilic attackof the bromide anion to this centre occurs from the endo face and the exo,endo-isomer of the N-type product is obtained. The attack of bromide anion, towards the cationic centre of U-type ion from the endo face is sterically hindered by the hydrogen atom therefore the attack occurs from the exo face, which interacts with the benzene ring and the more stable exo,exo-isomer of U-type product is formed. Although, the U-type cation was 2.232 kcal mol(-1) more stable than the N-type cation, the U-type product was 0.587 kcal mol(-1) less stable than the N-type product.     

Di(2-pyridyl)-Amides and -Phosphides: Syntheses,Reactivity, Structures,Raman-Experiments and Calculations

The 2-pyridyl containing compounds (2-Py)₂NH 1, (2-Py)₂PH 2, Me₂Al(2-Py)₂N 3, Me₂Al(2-Py)₂P 4, Et₂Al(2-Py)₂N 5, Et₂Al(2-Py)₂P 6 and Et₂Al(2-Py)₂NAlEt₃ 7 have been synthesized and analyzed by solid state structure determination, FT-Raman spectroscopy and theoretical calculations in order to elucidate the charge density distribution. All di(2-pyridyl) amides and -phosphides coordinate the R₂Al⁺ fragment via both ring nitrogen atoms, but the Lewis basicity of the central two-coordinated nitrogen atom in 5 is high enough to coordinate a second equivalent AlEt₃ to form the Lewis acid base adduct Et₂Al(2-Py)₂NAlEt₃ 7. Several density functionals (BLYP, B3LYP, BPW91) have been examined in relation to various basis sets (6-31G, 6-31+G, 6-31G(d), 6-31+G(d)). This computational tool facilitates the unambiguous assignment of the Raman ring vibration frequencies. The shift to higher wavenumbers proceeding from the parent di(2-pyridyl)amine 1 and di(2-pyridyl)-phosphane 2 to the metal complexes 3 and 4 indicates partial double bond localization in the ring positions 3 and 5. This effect is more pronounced in the di(2-pyridyl)amide complexes than in the phosphide. Due to the higher electronegativity of the central nitrogen atom in 3, 5 and 7 compared to the bridging two-coordinated phosphorus atom in 4 and 6 the di(2-pyridyl)amide is the harder Lewis base. In the phosphides nearly all charge density couples into the rings leaving the central phosphorus atom only attractive for soft metals.     

Host-guest properties of the trinuclear arene-ruthenium cluster cation [H3Ru3(C6H6)(C6Me6)2(O)]

The trinuclear arene-ruthenium cluster cation [H₃Ru₃(C₆H₆)(C₆Me₆)₂(O)]⁺, containing a μ₃-oxo cap and three arene ligands that span a hydrophobic pocket above the metal skeleton, has been crystallised as tetrafluoroborate salt in the presence of various guest molecules. The host-guest complexes have been characterised by single-crystal X-ray structure analysis. With chloroform as the guest molecule, a CHCl₃ molecule sits perfectly in the hydrophobic pocket, the hydrogen atom being encapsulated inside the cavity. When dioxane is added during the crystallisation process, the cluster forms infinite chains which are connected by a complex network of hydrogen bonds involving the μ₃-oxo ligand, water and dioxane molecules. Interestingly, in the presence of phenol, a water molecule is hydrogen-bonded between the μ₃-oxo ligand and the phenol molecule, forming a one-dimensional μ₃-O ? H₂O ? HO hydrogen-bonded chain. Finally, with benzoic acid, a head-to-tail host-guest chain is obtained, the phenyl ring being incorporated in the hydrophobic pocket, while the acid group is hydrogen-bonded to the μ₃-oxo ligand.     

Stability and cleavage conditions of (2-furyl)-L-alanine-containing peptides

The furyl group of (2-furyl)-L-alanine-containing peptides obtained from Fmoc solid-phase synthesis is partially degraded to several by-products during the final TFA-mediated deprotection in the presence of cation scavengers such as ethanedithiol and propanedithiol. The major by-product corresponds to a bis-dithioacetale formed after acidic hydrolysis of the furyl group. We examined several cleavage conditions and found that cleavage cocktails containing water and triisopropylsilane or 3,6-dioxa-1,8-octanedithiol (DODT) in trifluoroacetic acid are sufficient to minimize the side reaction.     

Reactions and structures in the gallium(III)/indium(III)-N,N-dimethylthioformamide systems

The structure of the N,N-dimethylthioformamide (DMTF) solvated gallium(III) ion has been determined in solution by means of extended X-ray absorption fine structure (EXAFS) spectroscopy. The gallium(III) ion is four-coordinate in tetrahedral fashion with a mean Ga-S bond distance of 2.233(2) Å in DMTF solution. At the dissolution of indium(III) perchlorate or trifluoromethanesulfonate in DMTF coordinated solvent molecules are partly reduced to sulfide ions, and a tetrameric complex with the composition [In₄S₄(SHN(CH₃)₂)₁₂]⁴⁺ is formed. The structure of the solid tetrameric complex in the perchlorate salt was solved with single crystal X-ray diffraction. Four indium(III) ions and four sulfide ions form a highly symmetric heterocubane structure where each indium binds three bridging sulfide ions and each sulfide ion binds three indium(III) ions with a mean In-S bond distance of 2.584(1) Å, and S-In-S angles of 90.3(1)°. Each indium(III) additionally binds three DMTF molecules at significantly longer mean In-S bond distance, 2.703(1) Å; the S-In-S angles are in the range 80.3-90.4°. Large angle X-ray scattering data on a DMTF solution of indium(III) trifluoromethanesulfonate show that the same tetrameric species characterized in the solid state is also present in solution, whereas the EXAFS measurements only give information about the In-S bond distances due to the short core hole lifetime.     

Six-coordinate phosphorus compounds. Crystal structures and dynamic NMR studies of phosphoranes containing chelating ligands

Hexacoordination of the neutral phosphorus compounds 4–6 is evidenced by their high field ³¹P NMR chemical shifts and is further substantiated by the crystal structure of 5 and 6.5 contains the potentially bis-chelating ligand Ar = (C₆H₃(CH₂NMe₂)₂-2,6) and 6 the same ligand with a protonated amino group. In both cases the compounds exhibit slightly distorted octahedral geometry. In compound 5, only one NMe₂ group is coordinated to the phosphorus atom with an N → P bond of 2.063 Å. In compound 6, the NMe₂ group is coordinated to the phosphorus atom with an N → P bond of 2.007 Å while the dimethylammonium substituent is pointing away from the phosphorus atom forming a hydrogen bridge with two oxygen atoms. The fluxional behavior of these three novel six-coordinate phosphorus compounds was studied by dynamic ¹H NMR spectroscopy.     

Promotion of root elongation by phosphorus deficiency

Decrease of culture solution pH and increase in cation/anion ratio in the plant were observed when horsegram (Macrotyloma uniflorum (Lam.) Verdc.) was grown in solution culture deficient in phosphorus. The effux of H⁺ from the roots of –P plants was observed in bromocresol purple agar. The length of root cells was considerably increased by –P treatment. Thus a close correlation between H⁺ excretion, length of the root cells and root elongation in response to P deficiency was established.     

Isolation and identification of urinary metabolites of AF-2 (3-(5-nitro-2-furyl)-2-(2-furyl)acrylamide) in rabbits

After oral administration of AF-2 (3-(5-nitro-2-furyl)-2-(2-furyl)acrylamide) to rabbits, the two unique metabolites, M-I and M-II, were isolated from the urine. M-I, yellow needles of mp 117°, was identified as a new type metabolite of nitrofuran derivative, 2-(β-carboxypropionyl)-3-(5-methylthio-2-furyl) acrylamide by its mass, ir and nmr spectrometries. M-II, yellow solid, appears to be cis-trans isomer of M-I considering from its uv and mass spectral data, and the behavior on tlc.     

不同氮磷浓度下周丛生物对水体中磺胺和恩诺沙星的去除

周丛生物膜是一种对水体污染物净化的新兴生物技术。有关水体不同氮磷营养水平下周丛生物对水体抗生素类污染物去除作用的研究还未见报道。本研究设置4个氮磷营养盐浓度水平[N-P (mg·L^-1):2-0.2、5-0.5、8-0.8、11-1.1],用塑料筐装置在室外培养周丛生物膜,对其生长、光合活力、物种组成以及对磺胺和恩诺沙星去除作用进行中型模拟试验。结果表明: 各处理组中周丛生物的生物量随培养时间的增加而升高,光合色素含量和光合活力则呈现先降低后上升的“单峰”模式,表明生物膜中的藻类会受到抗生素的胁迫,但可快速适应并恢复活力。除此之外,不同氮磷浓度处理造成各组生物群落组成差异,随营养盐浓度的升高,周丛藻类物种丰富度逐渐下降,但各处理胶网藻和小球藻都具有较高的相对丰度;16S rRNA高通量测序发现,根瘤菌科、放线菌门和莫拉氏菌科菌群在(N-P)2-0.2组显著富集,而几丁质嗜菌科在4个处理中的相对丰度都处在最高水平。所有处理的磺胺去除率均高于50%,而恩诺沙星去除率均达到90%以上,其中,(N-P)2-0.2 mg·L^-1组对磺胺的去除率(65.8%)显著高于其他各组,但各处理对恩诺沙星的去除率差异不显著,表明周丛生物在较宽的N-P营养水平范围内对磺胺和恩诺沙星均具有良好的去除能力。各处理组对水体可溶性氮的去除效果不明显,但对可溶性磷的去除效果显著。本研究为水体磺胺和恩诺沙星的生态去除提供了基础数据,为研发水体抗生素类新型污染物生态去除技术提供了新思路。     

Developmental Histology of Organogenic and Embryogenic Tissue in Picea omorika Culture

Newly synthesized derivatives of α-aminoalkanephosphonic acids (aminophosphonates) differ in the substituents at the carbon, nitrogen, and phosphorus atoms. They modified in different degree the properties of cucumber (Cucumis sativus cv. Wisconsin) cotyledon membranes, physiological activity of some enzymes (guaiacol and pyrogallol peroxidases, and catalase), chlorophyll content, and cellular membrane lipid peroxidation. Most active modifiers were those possessing sufficiently long hydrocarbon substituents at the nitrogen atom (C₁₀H₂₁) or isopropyl chain at the phosphorus atom. The branched tertbutyl group at the carbon atom enhanced slightly the activities of peroxidases in contrast to hexane ring at the same position, which decreased them. This revised version was published online in July 2006 with corrections to the Cover Date.     

Structural diversity in five-coordinate nickel(II) complexes of the tripyrrin ligand

Three different five coordinate nickel(II) complexes of tripyrrin ligands with chloro, oxalato and nitrato anionic ligands were obtained by ligand exchange reactions from respective trifluoroacetato species prepared in situ. Crystallographic studies of these compounds revealed different coordination geometries as well as different packing pattern. In the solid, the chloride complex accepts one water ligand to form a distorted trigonal bipyramid with two N donor centers in apical and one in an equatorial position. The molecules are organized in the crystal via hydrogen bonds, resulting in endless chains. Oxalate serves as a bridging ligand between two nickel(II) tripyrrins. Again the coordination of nickel(II) is found to be trigonal bipyramidal but with two equatorial and one apical nitrogen donors. The discrete dinuclear complexes are arranged in the crystal in a way as to form channels filled with toluene molecules. The nitrate species displays a η² bound nitrate ligand and short contacts between the nickel(II) center and an ethyl substituent of a neighboring molecule. The complex shows an unusually distorted molecular structure and unexpected differences in the two Ni-O bond lengths.     

QM/MM study of the insertion of metal ion into protoporphyrin IX by ferrochelatase

Ferrochelatase catalyzes the metallation of protoporphyrin IX in the terminal step of heme biosynthesis. Mutations in the ferrochelatase gene can lead to the disease erythropoietic porphyria. The catalyzing mechanism of ferrochelatase is still not fully understood. In this paper, we have studied the insertion of Fe²⁺ into the protoporphyrin IX ring by Bacillussubtilis ferrochelatase using combined quantum mechanical and molecular mechanics (QM/MM) calculations. Geometries were optimized at the BP86/6-31G∗ level and energies were calculated at the B3LYP/TZVP level. The overall process involves the stepwise displacement of Glu-264, His-183, and a water molecule from Fe²⁺, and the removal of two protons from the porphyrin ring. The rate-determining step is the cleavage of the bond between the oxygen atom of Glu-264 and Fe²⁺, concomitant with the formation of the first Fe-N bond. It has an energy barrier of 57 kJ mol⁻¹. The porphyrin ring is only slightly distorted in the enzyme active site. The residue Tyr-13 plays a key role for the catalytic process extracting two protons from protoporphyrin IX.     

Inhibition of chemical dose in biological phosphorus and nitrogen removal in simultaneous chemical precipitation for phosphorus removal

A study on the influence of chemical dosing on biological phosphorus and nitrogen removal was carried out through batch experimental tests by lab-scale and a full-scale wastewater treatment plant (employing a typical anaerobic-anoxic-oxic treatment). Results indicated that the inhibition of aluminum salt on biological phosphorus release and uptake processes is significant, as well as the inhibition of aluminum salt on Ammonia-Oxidizing Bacteria (AOB) is dominantly observed in the nitrification process and is recoverability. The inhibition of iron salt in biological phosphorus and nitrogen removal is weak, and only the inhibition of iron salt on phosphorus release at anaerobic periods emerge under large dosing. Evidence shows persistent inhibition from the accumulation of chemical doses in sludge mass. Intermittent chemical dosing proves recommendable for simultaneous chemical phosphorus removal.     

Structure-activity relationships of novel anti-malarial agents. Part 4: N-(3-benzoyl-4-tolylacetylaminophenyl)-3-(5-aryl-2-furyl)acrylic acid amides

In a previous report, we have described novel anti-malarial compounds based on a 2,5-diaminobenzophenone scaffold. Here, we have invesigated acryloyl derivatives carrying a biaryl structure consisting of a terminal aryl residue and a central 2-furyl ring. Several compounds were obtained in the series of para-substituted phenylfurylacryloyl derivatives that displayed improved anti-malarial activity in comparison to earlier described derivatives. From the structure-activity relationships it can be deduced that there has to be a lipophilic moiety in the para-position of the terminal phenyl residue. Furthermore, there are indications that, alternatively, activity may benefit from the presence of a polar moiety with hydrogen bond acceptor properties.