Speciation of copper(II) in natural waters in the presence of ligands of high and intermediate strength

Abstract

A new procedure is presented for the determination of the ligands of copper(II) in natural waters, based on titration with the metal ion, monitored by measuring the concentration of copper(II) sorbed on the carboxylic resin Amberlite CG 50. The data are treated by the Ruzic linearization method to obtain the concentration of the ligands and the conditional stability constant of the complexes. Ligands with reaction coefficient α_M higher than 0.1 K*w/V are detected, where K* is the ratio of the concentration of sorbed metal to the concentration of free metal in solution, which can be evaluated from the sorption equilibria of copper(II) on Amberlite CG 50, w is the amount of water in the resin phase, and V the volume of the solution phase. Some natural waters at high and low salinity were examined. The ligand concentration determined in these samples ranged from around 50 to 2000 nM, while the original copper concentrations from 11 to 130 nM. The ligand concentration was always much higher than that of copper(II). The conditional stability constants were very high, particularly in low salinity waters, where values as high as K’= 10^15.7 were obtained. In high salinity waters values around 10⁹ were found for the complex formation constant of the ligands titrated with copper(II). The investigation was also extended to a model solution, containing EDTA, obtaining K’ = 10^15.5, in acceptable agreement with that evaluated from the literature values.     

Xylitol Production by a Corynebacterium Species

The washed cells of a gluconate-utilizing Corynebacterium strain grown in a gluconate- xylose medium produced xylitol from D-xylose in the presence of gluconate. The amount of xylitol was progressively increased with increasing gluconate concentration.

An extract of cells grown in the gluconate-xylose medium showed NADPH-dependent D-xylose reductase activity and NADP-dependent 6-phosphogluconate dehydrogenase activity.

These enzymes in the cell-free extract were purified by Sephadex G–100 gel filtration.

The reduction of D-xylose to xylitol was demonstrated by the coupling the D-xylose reductase activity to the 6-phosphogluconate dehydrogenase activity with NADP as a cofactor using the cell-free extract and the fractionated enzymes.     

Products Formed by Photosensitized Oxidation of Tocopherols

Two isomers of primary products formed by méthylene blue sensitized photooxidation of δ-tocopherol were separated by thin layer chromatography. The products were characterized by UV, IR and NMR spectra and were identified to be 8aS- and 8aR-hydroperoxy δ-tocopheryl dienones, respectively. On decomposition of the photooxidized α-, γ- and δ-tocopherols, to-copheryl quinone and tocopheryl quinone epoxide were formed. The effect of hydroperoxy 5-tocopheryl dienone on methyl linoleate peroxidation was examined. The hydroperoxy dienone formed by the photooxidation of tocopherols did not accelerate lipid peroxidation.     

Heteropatric speciation in a duck,Anas crecca

Heteropatric differentiation is a mode of speciation with gene flow in which divergence occurs between lineages that are in sympatry and allopatry at different times during cyclic spatial movements. Empirical evidence suggests that heteropatric differentiation may prove to be common among seasonally migratory organisms. We examined genetic differentiation between the sedentary Aleutian Islands population of green‐winged teal (Anas crecca‐nimia) and its close migratory relative, the Eurasian, or Old World (OW), Anas c. crecca population, a portion of which passes through the range of nimia during its seasonal migrations. We also examined its relationship with the parapatric North American, New World (NW), A. c. carolinensis population. Sequence data from eight nuclear introns and the mtDNA control region showed that the nimia‐crecca divergence occurred much more recently than the deeper crecca‐carolinensis split (~83 000 years vs. ~1.1 Myr). Despite considerable spatial overlap between crecca and nimia during seasonal migration, three key predictions of heteropatric differentiation are supported: significant genetic divergence (overall mean Φ_st  = 0.07), low gene flow (2N_em ~ 1.8), and an effective population size in nimia that is not especially low (N_e ~ 80 000 individuals). Similar levels of gene flow have come into nimia from carolinensis, but no detectable nuclear gene flow has gone out of nimia into either OW (crecca) or NW (carolinensis) populations. We infer that adaptations of these populations to local optima in different places (e.g. each matching their reproductive effort to different resource blooms) promote genetic isolation and divergence despite periods of sympatry between them, as the heteropatric model predicts.     

Stepwise colonization of the Andes by Ruddy Ducks and the evolution of novel β‐globin variants

Andean uplift played a key role in Neotropical bird diversification, yet past dispersal and genetic adaptation to high‐altitude environments remain little understood. Here we use multilocus population genetics to study population history and historical demographic processes in the ruddy duck (Oxyura jamaicensis), a stiff‐tailed diving duck comprising three subspecies distributed from Canada to Tierra del Fuego and inhabiting wetlands from sea level to 4500 m in the Andes. We sequenced the mitochondrial DNA, four autosomal introns and three haemoglobin genes (α^A, α^D, β^A) and used isolation‐with‐migration (IM) models to study gene flow between North America and South America, and between the tropical and southern Andes. Our analyses indicated that ruddy ducks dispersed first from North America to the tropical Andes, then from the tropical Andes to the southern Andes. While no nonsynonymous substitutions were found in either α globin gene, three amino acid substitutions were observed in the β^A globin. Based on phylogenetic reconstruction and power analysis, the first β^A substitution, found in all Andean individuals, was acquired when ruddy ducks dispersed from low altitude in North America to high altitude in the tropical Andes, whereas the two additional substitutions occurred more recently, when ruddy ducks dispersed from high altitude in the tropical Andes to low altitude in the southern Andes. This stepwise colonization pattern accompanied by polarized β^A globin amino acid replacements suggest that ruddy ducks first acclimatized or adapted to the Andean highlands and then again to the lowlands. In addition, ruddy ducks colonized the Andean highlands via a less common route as compared to other waterbird species that colonized the Andes northwards from the southern cone of South America.     

Association between pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections disease and tumor necrosis factor-α gene?308 g/a, ?850 c/t polymorphisms in 4-12-year-old children in Adana/Turkey

OBJECTIVES:

Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infections (PANDAS) is a newly defined disease in neuropsychiatry and occurs with an autoimmune mechanism after Group A Beta Hemolytic Streptococcus (GABHS) infection. Tumor necrosis factor (TNF), encoded by TNF-α gene has an important role in the apoptotic mechanisms of autoimmune diseases. Recently, TNF-α polymorphisms and autoimmune/psychiatric disorders have been reported to be related. In this regard, we focused on to investigate a possible relation between the TNF-α gene promoter region−308 G/A and − 850 C/T polymorphisms and PANDAS.

MATERIALS AND METHODS:

In this study, ages of PANDAS patient and control groups were ranging from 4 years to 12-year-old. Patient group includes childhood onset PANDAS patients (n = 42) and control group includes healthy children (n = 58). Diagnoses have been carried out according to Diagnostic and Statistical Manual of Mental Disorder (DSM-IV) criteria with Affective Disorders and Schizophrenia-Present and Lifetime (KSAD-S-PL) and Children Yale-Brown Obsessive Compulsive Scale Moreover, PANDAS criteria established by the American National Psychiatry Institute have been employed for diagnoses. For identifying polymorphisms; Polymerase Chain Reaction, Restriction Fragment Length Polymorphism and Polyacrylamid Gel Electrophoresis were used.

RESULTS AND DISCUSSION:

For −308 polymorphism, 37 of 42 PANDAS patients’ results and for −850 C/T polymorphism, 38 of 42 PANDAS patients’ results were obtained. According to our statistical analysis there is a positive relationship between PANDAS patients for −308 G/A polymorphism but not for −850 C/T polymorphism. There is no positive relationship between −308 G/A polymorphism and antistrep-tolysin O (ASO) titers and no relationship between −850 C/T polymorphism and ASO titers. We found, however, positive relationship between genders of patients (boys) and the disease. According to our results, we propose that the AA polymorphism of −308 G/A polymorphism can be used as a molecular indicator for PANDAS.     

倒木覆盖对天宝岩国家级自然保护区长苞铁杉林内土壤理化特性的影响

以天宝岩国家级自然保护区长苞铁杉(Tsuga longibracteata W.C.Cheng)林为研究对象,研究了有无倒木覆盖以及倒木腐烂程度对土壤8项理化指标(包括含水量,容重,总孔隙度,有机碳、全N、全P和全K含量以及C/N比)的影响,并比较了经倒木覆盖后不同季节和不同类型林分中土壤8个理化指标的变化.结果显示:与无倒木覆盖的土壤相比,经倒木覆盖后土壤容重降低,总孔隙度及含水量提高,有机碳、全N及全K含量均增加,说明倒木覆盖总体上提高了长苞铁杉林下土壤的肥力,但有无倒木覆盖对土壤理化性质无显著影响.经不同腐烂程度倒木覆盖后土壤有机碳含量有显著差异(P＜0.05)并随倒木腐烂程度提高大体呈现逐渐升高的趋势,但土壤的其他7个理化指标无显著差异;经中等(Ⅲ级)腐烂倒木覆盖后土壤的全N、全P和全K含量均最高.经倒木覆盖后,不同季节土壤的全P含量无显著变化,而其他7个理化指标在不同季节均有显著变化(P＜0.05);经倒木覆盖后秋、冬、春、夏土壤容重和全K含量依次增加,总孔隙度和有机碳含量依次降低,土壤含水量在秋季最低、春季则最高.整体来看,在长苞铁杉林的不同类型林分内经倒木覆盖后土壤8个理化指标均有显著差异(P＜0.05);与供试的4类混交林相比,在长苞铁杉纯林内经倒木覆盖后土壤的含水量、容重和全K含量均最高,总孔隙度最低,有机碳含量相对较低,C/N比及全N和全P含量居中.研究结果表明:在天宝岩国家级自然保护区长苞铁杉林内,倒木覆盖有利于改善土壤理化性质、提高土壤肥力.     

沟垄全覆盖种植方式对旱地玉米生长及水分利用效率的影响

2008-2010年在渭北旱塬区,以沟不覆盖为对照(CK),研究垄上覆地膜沟内分别覆普通地膜(PP)、生物降解膜(PB)、玉米秸秆(PS)和液体地膜(PL)4种沟垄全覆盖种植模式对土壤水温、玉米生长、产量及水分利用效率的影响.结果表明,在玉米生长前期,PP、PB和PS处理可明显提高0-200 cm土壤蓄水量;生育中期,PS处理蓄水保墒效果最为显著;生育后期,各沟垄全覆盖处理与对照的土壤蓄水量无显著差异;整个生育期PL处理与CK的土壤蓄水量差异不显著.PP和PB处理3a玉米生育期5-25 cm平均土壤温度分别较CK增高1.6℃和1.3℃,PS处理降低1.9℃,而PL处理与CK无显著差异.PP和PB的增温保水效应使玉米株高、叶面积及地上生物量均高于CK;PS处理的降温效应促进玉米中后期生长,其株高、叶面积及地上生物量均高于CK;PL处理对玉米各生长指标影响不显著.与CK相比,PP、PB和PS处理3a平均的籽粒产量分别提高13.0％、13.8％和15.0％,水分利用效率分别提高9.8％、10.2％和11.6％.可见,垄覆地膜沟覆地膜、生物降解膜或秸秆的沟垄全覆盖种植可明显改善土壤的水温状况,促进玉米生长,从而显著提高作物产量和水分利用效率,对渭北旱塬区春玉米丰产栽培具有重要指导意义.     

青核桃冷藏期间氧化状态分析

为了解青核桃在冷藏期间的氧化状态,该文以青核桃为材料,研究其在低温冷藏中果仁含水量、酸价(AV)、过氧化值(POV)、碘值(IV)、过氧化氢酶(CAT)、脂氧合酶(LOX)、丙二醛(MDA)的变化。结果表明:冷藏期间,青核桃果仁水分含量、IV呈逐渐降低趋势; CAT活性保持良好; AV、POV、LOX活性、MDA含量总体上表现为上升趋势;主体间效应检验得出,冷藏时间对青核桃品质影响显著(P0.05)。IV、果实含水量两两之间均呈极显著性正相关(P0.01),AV、POV、LOX及MDA两两之间表现为极显著性正相关(P0.01);部分指标呈(极)显著性负相关;主成分分析结果表明,果仁含水量、AV、POV、IV、MDA、CAT、LOX与果实品质关系密切,可作为评价其氧化程度的重要指标。青核桃采摘预冷后,在温度为1～2℃、相对湿度为85%～90%的条件下可贮藏18 d。以上结果可为青核桃冷藏提供理论依据和基础数据。