海洋铁细菌对紫铜腐蚀行为的影响

【目的】研究海洋铁细菌(Iron-oxidizing bacteria,IOB)对铜的腐蚀影响。【方法】采用电化学极化曲线、电化学阻抗谱(EIS)研究紫铜在海洋环境铁细菌影响下的腐蚀行为。【结果】扫描电子显微镜SEM形貌分析结果表明,在紫铜上附着的铁细菌呈杆状。电化学测试结果表明紫铜在含IOB海水中的腐蚀过程主要受活化极化控制,有菌海水的活化电阻比无菌海水的小6 000.cm2,表明在含IOB的海水中铜发生溶解反应受到的阻滞较小。【结论】IOB的存在导致紫铜的自腐蚀电位变小,使得紫铜发生腐蚀的倾向变大;IOB也使紫铜的阳极极化曲线塔菲尔斜率和变小,从而加速了紫铜的腐蚀进程。     

Distribution of nickel,zinc, and copper in rat organs after oral administration of nickel(II) chloride

The distribution of Ni administered as NiCl₂ · 6H₂O in the drinking water (300 and 1200 ppm Ni for 90 d) was studied using male Wistar rats. Next, the effect of Ni on the concentration of zinc (Zn) and copper (Cu) in selected organs and serum was measured. The metals were analyzed in the liver, kidney, lung, spleen, brain, and serum by electrothermal (Ni) or flame (Zn, Cu) atomic absorption spectrophotometry. The results indicate that exposed rats drank less nickel solutions than the volume of water drunk by controls, but there was no mortality of animals. In comparison to control animals, a very high increase in Ni levels was found in the kidney and then lung and serum of all exposed rats. In the liver, spleen, and brain, the metal accumulation was lower. A directly proportional relation between the nickel intake and its deposition was observed in the collected organs and in the serum. The metal level did not change significantly in the course of exposure (the first analysis was after 30 d). The administration of 300 ppm Ni did not affect the zinc and copper concentration in studied organs, except the serum, where zinc content was significantly reduced. At a dose of 1200 ppm Ni, these metals were found to be depressed in the liver, kidney, serum (zinc), and copper in the kidney.     

Comparative studies of nickel,cobalt, and copper uptake by some nickel hyperaccumulators of the genus Alyssum

The uptake of Ni, Co, and Cu by the nickel hyperaccumulator Alyssum troodii Boiss and the non-accumulator Aurinia saxatilis (L.) Desv. were studied in pot trials using artificial rooting media with varying concentrations of the metals added as soluble salts, singly and in combination. The ability of five other Ni hyperaccumulating species of Alyssum to hyperaccumulate Co was also investigated.Leaves and stems of A. troodii accumulated Ni to almost the same extent (8000–10 000 g g^-1). In roots, the highest Ni concentration was 2000 g g^-1. In leaves of Au. saxatilis, the maximum Ni concentration was only 380 g g^-1 and the level in roots was even lower.In media containing Co, the maximum concentration of this element in A. troodii (2325 g g^-1) was ten times higher than in the non-accumulator species. Slightly less Co was found in stems and roots of both species. Among the other Ni hyperaccumulators, the maximum concentration of Co in leaves ranged from about 1000–8000 g g^-1.Copper concentrations were the same in all organs of both species when they were grown in copper-rich media and were in the range 40–80 g g^-1, showing that neither plant was capable of taking up Cu at levels comparable to those of Ni and Co.When both plants were grown in media containing equal amounts of both Co and Ni, the Co concentrations in plant organs were the same as for specimens grown in media containing Co only. However, the Ni levels were lower in both species. Uptake of Co therefore appeared to suppress Ni uptake.Pot trials showed that the order of tolerance was Ni>Cu>Co for A. troodii and Ni>CoCu for Au. saxatilis, whereas the seedling tests showed the order to be Co>Ni>Cu. At metal concentrations 10 000 g g^-1, the overall tolerance of A. troodii was greater than that of Au. saxatilis which exhibited equally low tolerance to Ni and Cu.We conclude that in A. troodii, A. corsicum Duby, A. heldreichii Hausskn., A. murale Waldstein & Kitaibel, A. pintodasilvae T.R. Dudley, and A. tenium Hálácsy, Ni tolerance and hyperaccumulation conveys the same character towards Co. This behaviour should be investigated in other hyperaccumulators of Ni and/or Co.     

Probing copper2+ binding to the prion protein using diamagnetic nickel2+ and 1H NMR: the unstructured N terminus facilitates the coordination of six copper2+ ions at physiological concentrations

The prion protein (PrP) is a Cu2+ binding cell surface glyco-protein. Misfolding of PrP into a beta-sheet rich conformation is associated with transmissible spongiform encephalopathies. Here we use Ni2+ as a diamagnetic probe to further understand Cu2+ binding to PrP. Like Cu2+, Ni2+ preferentially binds to an unstructured region between residues 90 and 126 of PrP, which is a key region for amyloidogenicity and prion propagation. Using both 1H NMR and visible-circular dichroism (CD) spectroscopy, we show that two Ni2+ ions bind to His96 and His111 independently of each other. 1H NMR indicates that both Ni2+ binding sites form square-planar diamagnetic complexes. We have previously shown that Cu2+ forms a paramagnetic square-planar complex in this region, suggesting that Ni2+ could be used as a probe for Cu2+ binding. In addition, competition studies show that two Cu2+ ions can displace Ni2+ from these sites. Upon Ni2+ addition 1H NMR changes in chemical shifts indicate the imidazole ring and amide nitrogen atoms to the N terminus of both His96 and His111 act as coordinating ligands. Use of peptide fragments confirm that PrP(92-96) and PrP(107-111) represent the minimal binding motif for the two Ni2+ binding sites. Analysis of Cu2+ loaded visible-CD spectra show that as with Ni2+, PrP(90-115) binds two Cu2+ ions at His96 and His111 independently of each other. Visible CD studies with PrP(23-231Delta51-90), a construct of PrP(23-231) with the octarepeat region deleted to improve solubility, confirm binding of Ni2+ to His96 and His111 in octarepeat deleted PrP(23-231). The structure of the Cu/Ni complexes is discussed in terms of the implications for prion protein function and disease.     

An assessment of alternative diesel fuels: microbiological contamination and corrosion under storage conditions

Experiments were designed to evaluate the nature and extent of microbial contamination and the potential for microbiologically influenced corrosion of alloys exposed in a conventional high sulfur diesel (L100) and alternative fuels, including 100% biodiesel (B100), ultra-low sulfur diesel (ULSD) and blends of ULSD and B100 (B5 and B20). In experiments with additions of distilled water, all fuels supported biofilm formation. Changes in the water pH did not correlate with observations related to corrosion. In all exposures, aluminum 5052 was susceptible to pitting while stainless steel 304L exhibited passive behavior. Carbon steel exhibited uniform corrosion in ULSD and L100, and passive behavior in B5, B20, and B100.     

油田硫酸盐还原菌酸化腐蚀机制及防治研究进展

硫酸盐还原菌(Sulfate reducing bacteria,SRB)是一些厌氧产硫化氢的细菌的统称,是以有机物为养料的厌氧菌。它们广泛分布于pH值6-9的土壤、海水、河水、淤泥、地下管道、油气井、港湾及锈层中,它们生存于好气性硫细菌产生的沉积物下,其最适宜的生长温度是20-30℃,可以在高达50-60℃的温度下生存,与腐蚀相关的最主要的是脱硫脱硫弧菌(Desulfovibrio desulfuricans)。 它们是许多腐蚀问题的主因,例如油田系统金属管路的腐蚀等。在海上油田生产中,海水常被注入油井用于进行2次采油。富含硫酸盐的海水能加速油藏中SRB的生长,随之H₂S大量产生,引起油田水的酸化,H₂S具有毒性和腐蚀性,增加石油和天然气中的硫含量,并可能引起油田堵塞。SRB引起的腐蚀问题是拭待解决的最主要问题。国内外治理该问题的途径主要有物理杀灭、添加化学杀菌剂等方法,但是这些方法成本高,持续效果不显著。近几年来国外学者开始重点关注利用生物竞争排斥技术(Bio-competitive inhibition technology,BCX)控制硫酸盐还原菌的生长代谢的方法,该方法的原理为通过加入特定的药剂,激活油藏中的本源微生物或加入外源微生物,使其与SRB竞争营养源或产生代谢物抑制SRB的生长代谢,进而抑制H₂S的产生。GMT-LATA的科学家对在厌氧油气储层和开采系统中硝酸盐还原菌的作用进行了最早的研究,认为该细菌可以抑制硫酸盐还原菌的代谢活动。随后BCX技术已经在国外部分油田得到了应用,国内还没有在海油生产中应用的报道,但是也有学者对该方法进行了研究。     

Erythrocyte catalase activity in chronic renal failure patients and donors in the presence of metal lons

The effect of hemodialysis on erythrocyte catalase (CAT) activity was studied in chronic renal failure (CRF) patients. This enzyme was analyzed in vitro, and its activity throughout the incubation period was found to be 34% lower than in healthy donors. The influence of Al³⁺, Cu²⁺, and Ni²⁺ on CAT activity in donor's blood (in vitro) is also studied, for short incubation periods at trace levels of 2.5, 0.25, and 0.196 mM, respectively. With Al³⁺ and Cu²⁺, there is a decrease in the enzyme activity. With Ni²⁺, there is at first a similar decrease, followed by a recovery in activity up to control values.     

Role of Toxoplasma gondii HSP70 and Toxoplasma gondii HSP30/bag1 in antibody formation and prophylactic immunity in mice experimentally infected with Toxoplasma gondii.

Production of antibodies against Toxoplasma gondii (T. gondii)-derived stress proteins, T. gondii HSP70 (T.g.HSP70) and T.g.HSP30/bagl, in C57BL/6 and BALB/c mice perorally infected with cysts of the avirulent Fukaya strain of T. gondii was analyzed. Production of anti-T.g.HSP70 IgG antibodies was transient, whereas production of anti-T.g.HSP30/bag1 IgG antibodies persisted after infection in both C57BL/6 and BALB/c mice. C57BL/6 mice, a susceptible strain, predominantly produced IgG antibodies specific for T.g.HSP70, whereas BALB/c mice, a resistant strain, predominantly produced IgG antibodies specific for T.g.HSP30/bag1, after T. gondii infection. Immunization with rT.g.HSP30/bag1 enhanced, whereas immunization with rT.g.HSP70 reduced host protective immunity against T. gondii infection with a cyst-forming avirulent strain, Fukaya, and a virulent strain, RH.     

Enhancement of nickel and lead accumulation and their toxic growth-inhibitory effects on amaranth seedlings in the presence of calcium

The effects of Ni(NO₃)₂ and Pb(NO₃)₂ on Amaranthus sp. L. root growth and the effect of calcium on heavy metal (HM) accumulation in the growing root zone and root growth inhibition were studied. The seeds were germinated in the Pb(NO₃)₂ solutions at concentrations of 50, 100, 200, 500 and 700 μM or Ni(NO₃)₂ solutions at concentrations of 10, 50, 70, 100, and 500 μM in the presence of 100 μM Ca(NO₃)₂ or without it. HM toxicity was assesses in 7 days after seed sowing by the root length. Distribution of HM over the tissues of the growing root part was examined histochemically. Ni was more toxic to root growth than Pb. In the presence of Ca, Ni and Pb accumulation in the amaranth root growing part increased markedly, and this enhanced their growth-inhibitory of action. A comparison of results obtained in this work and available from the literature permitted a conclusion that the routes of HM penetration into the root differ in different plant species, and this determines ambiguity of protective Ca action.     

Mytilus trossulus hsp70 as a biomarker for arsenic exposure in the marine environment: Laboratory and real-world results

Acute renal papillary necrosis (RPN) in animals is characterized by increased renal lipid accumulation. The excretion of renal lipids into urine has been determined to evaluate their possible use as sensitive early biomarkers for the diagnosis of RPN. This study investigates injury induced by two model nephrotoxins, mefenamic acid (MFA), a non-steroidal anti-inflammatory drug (NSAID), and its analogue N-phenylanthranilic acid (NPAA). Oral NPAA was given repeatedly at doses of 100, 250 and 500 mg kg^-1 daily for 5 days, followed by a 2 day respite over the weekend, and then four further daily doses. The same dosing procedure was used with MFA, but at doses of 75, 150 and 300 mgkg^-1. The control groups were given vehicle orally using the same volume given to the test groups. Urinary phospholipids (PLs), notably sphingomyelin (SPM), phosphatidylcholine (PC) and phosphatidylethanolamine (PE), were measured and compared with other urinary parameters. Histopathological investigations were also performed to confirm the presence or absence of RPN. Following MFA treatment, PC, PI and PE were raised significantly (p < 0.001) on days 1 and 3 and for the remaining part of the experiment. After NPAA treatment, PI showed a transient elevation, and PC and PE levels were significantly increased from day 2 onwards. Both drugs caused a dose-related increase in PLs. There was no significant increase in the level of other urinary parameters. However, histopathological examination of the kidney on day 11 revealed lesions in the medulla and papilla following treatment with the two papillotoxins. These findings demonstrate the potential of urinary PLs as diagnostic non-invasive biomarkers for early renal injury associated with RPN, which may provide an important improvement in the approach to the therapeutic management of analgesic nephropathy.     

Non-lethal effects of an invasive species in the marine environment: the importance of early life-history stages

Studies examining the effects of invasive species have focussed traditionally on the direct/lethal effects of the invasive on the native community but there is a growing recognition that invasive species may also have non-lethal effects. In terrestrial systems, non-lethal effects of invasive species can disrupt early life-history phases (such as fertilisation, dispersal and subsequent establishment) of native species, but in the marine environment most studies focus on adult rather than early life-history stages. Here, we examine the potential for an introduced sessile marine invertebrate (Styela plicata) to exert both lethal and non-lethal effects on a native species (Microcosmus squamiger) across multiple early life-history stages. We determined whether sperm from the invasive species interfered with the fertilisation of eggs from the native species and found no effect. However, we did find strong effects of the invasive species on the post-fertilisation performance of the native species. The invasive species inhibited the settlement of native larvae and, in the field, the presence of the invasive species was associated with a ten-fold increase in the post-settlement mortality of the native species, as well as an initial reduction of growth in the native. Our results suggest that larvae of the native species avoid settling near the invasive species due to reduced post-settlement survival in its presence. Overall, we found that invasive species can have complex and pervasive effects (both lethal and non-lethal) across the early life-history stages of the native species, which are likely to result in its displacement and to facilitate further invasion.     

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.     

Role of DNA barcoding in marine biodiversity assessment and conservation: An update

More than two third area of our planet is covered by oceans and assessment of marine biodiversity is a challenging task. With the increasing global population, there is a tendency to exploit marine resources for food, energy and other requirements. This puts pressure on the fragile marine environment and necessitates sustainable conservation efforts. Marine species identification using traditional taxonomical methods is often burdened with taxonomic controversies. Here we discuss the comparatively new concept of DNA barcoding and its significance in marine perspective. This molecular technique can be useful in the assessment of cryptic species which is widespread in marine environment and linking the different life cycle stages to the adult which is difficult to accomplish in the marine ecosystem. Other advantages of DNA barcoding include authentication and safety assessment of seafood, wildlife forensics, conservation genetics and detection of invasive alien species (IAS). Global DNA barcoding efforts in the marine habitat include MarBOL, CeDAMar, CMarZ, SHARK-BOL, etc. An overview on DNA barcoding of different marine groups ranging from the microbes to mammals is revealed. In conjugation with newer and faster techniques like high-throughput sequencing, DNA barcoding can serve as an effective modern tool in marine biodiversity assessment and conservation.     

不同纬度螅状独缩虫耐热能力及Hsp70 mRNA表达水平的比较

本文以游泳体的形成作为虫体对热激响应的指征,比较了不同纬度 (西安:东经10 8°98′,北纬34°25′;武汉:东经114°34′,北纬30°57′) 两地螅状独缩虫 (Carc hesium polypinum) 的耐热能力,发现武汉地区螅状独缩虫 (WH株) 形成游泳体的热激温度 ( 36℃) 高于西安地区 (XA株) 的33℃,说明前者的耐热能力较强;进一步利用实时PCR技术分析不同热激温度下两地螅状独缩虫热休克蛋白Hsp70 mRNA的表达变化发现,XA株Hs p70 mRNA热激后高表达水平的阈值温度为28℃,而WH株的为33℃,表明在螅状独缩虫中, Hsp70 mRNA表达的阈值温度与它们的耐热能力之间存在正相关.从而在分子水平阐明了螅状独缩虫WH株较XA株具有更高耐热能力的原因,这为研究纤毛虫野生种群热休克蛋白Hsp7 0 mRNA表达与栖息环境温度间的关系,进而了解原生动物温度适应的分子机理提供了线索[动物学报 54(3):525-530,2008].     

Mapping of genes for copper efficiency in rye and the relationship between copper and iron efficiency

A 4B/5R wheat-rye translocation line derived from the Danish wheat variety Viking was revealed to be highly copper efficient. The chromosomal exchange includes a very small terminal segment of chromosome arm 5RL of rye which was physically mapped by genomic DNA: DNA in situ hybridization and chromosome analysis. The gene for Cu efficiency (Ce) is linked to a dominant hairy neck character from rye (Ha1) and to two rye-specific leaf esterase loci (Est6, Est7), all of which are postulated to map to the distal part of 5RL. Genes coding for mugineic acid synthetase and 3-hydroxymugineic acid synthetase also on chromosome 5R are not included in the 4B/5R translocation and hence map outside the terminal 5R region. These genetic and molecular markers can be useful tools for large-scale screening in wheat breeding programmes.     

Characterization of two heat shock proteins (Hsp70/Hsc70) from grass carp (Ctenopharyngodon idella): evidence for their differential gene expression, protein synthesis and secretion in LPS-challenged peripheral blood lymphocytes

Two cDNAs, encoding the stress-inducible 70-kDa heat shock protein (Hsp70) and the constitutively expressed 70-kDa heat shock cognate protein (Hsc70), were isolated from grass carp. The Hsp70 and Hsc70 cDNAs were 2250 bp and 2449 bp in length and contained 1932 bp and 1953 bp open reading frames, respectively. Tissue distribution results showed that Hsp70/Hsc70 was highly expressed in gill, kidney, head kidney and peripheral blood lymphocytes (PBLs). Using grass carp PBLs as a cell model, effects of lipopolysaccharide (LPS) on the mRNA and protein levels of Hsp70/Hsc70 were examined. In this case, LPS increased the mRNA expression of Hsp70 in a time- and dose-dependent manner, but had no effect on Hsc70 mRNA expression. In agreement with this, LPS elevated the intracellular Hsp70 markedly, but not the Hsc70 protein levels in parallel experiments. Furthermore, Hsp70 protein was also detected in culture medium. Moreover, inhibition of LPS on Hsp70 release in a time-dependent manner was observed, indicating that there may be a dynamic balance between Hsp70 stores and Hsp70 release in grass carp PBLs following exposure to LPS. Taken together, these results not only shed new insights into the different regulations of LPS on Hsp70/Hsc70 gene expression, protein synthesis and release, but also provide a basis for further study on the functional role of Hsp70 in fish immune response.     

Microbial biomass and bacteria in two pasture soils: An assessment of measurement procedures,temporal variations,and the influence of P fertility status

The reliability of three methods (microbial C and mineral-N flush by fumigation-incubation, and ATP) for measuring soil microbial biomass was assessed on two silt-loam soils of different P fertility status under grazed perennial pastures. The mineral-N flush and ATP methods provided a reasonably reliable index of microbial biomass, but the fumigation-incubation procedure for CO₂-C flush, using preincubated samples and an unfumigated 0–10 day control, was inappropriate for these soils. The numbers of bacteria (direct microscopy) and the percentage metabolically active were also measured. Generally, in both soils, total microbial biomass and the numbers, mass and metabolic activity of bacteria were influenced more by temporal factors in samples taken monthly than by the fertility status. Temporal fluctuations were greater in the high-fertility (Waikanae) soil, but no consistent seasonal trends in mineral-N flush and ATP values were apparent. In both soils, numbers and biomass of bacteria were at a minimum in spring. Values of two biomass indices (mineral-N flush and ATP contents) were similar in the high- and low-fertility (Pomare) soil, and comprised similar percentages of organic-matter contents. The percentages of metabolically active bacteria, however, tended to be higher in Pomare than in Waikanae soil, and, therefore, did not reflect soil fertility status. Methodological and field aspects of these results are discussed.     

Interaction between hypertension and HSP70 variants increase the risk of cerebral ischemia in Chinese Han population: An association study

Cerebral infarction has become one of the leading diseases and a major mortality factor around the world. Atherosclerosis is recognized as one of the important causes of ischemic stroke. Recently, accumulating evidences have indicated that the anti-inflammatory and anti-apoptotic functions of the HSP70 family play an important role in cerebral ischemia. However, the association between HSP70 SNPs and ischemic stroke was also not well established. We chose 101 cases of cerebral ischemia and 100 healthy people from the Chinese Han population as our study subjects, and PCR-RFLP was employed to analyze HSP70 polymorphisms: HSP70-1+190G/C, HSP70-2+1267A/G and HSP70-hom+2437T/C. There were no significant differences in + 1267A/G allele or genotype frequencies between patients with stroke and healthy controls. However, genotypes of + 190CG and + 2437TT were differentially distributed between the patients and controls. A significant difference of T allele distribution in the HSP70-hom+2437T/C site was observed. Logistic regression analysis indicated that genotypes of + 190CG, + 2437TT and T allele in HSP70-hom were risk factors of ischemic stroke. Moreover, the study has formulated that the interactions between hypertension and + 190CG or + 2437TT may increase the risks of ischemic stroke. The results from this study have suggested a clinical indicator for assessing the possibilities of cerebral stroke, and supply basis to clinicians to give precaution to people who are at risk of stroke.     

Influence of copper on the early post-implantation mouse embryo: An in vivo and in vitro study

Summary Female mice were injected intravenously with copper sulphate on either the 7th day (early egg cylinder stage of development), the 8th day (late egg cylinder stage), or the 9th day (early somite stage of development), and examined on the 10th day of gestation. Injection on the 7th day was found to be embryo-lethal; when females were injected on the 8th day, the majority of the surviving embryos exhibited anomalies of the neural tube and/or the heart, while injection on the 9th day resulted in a very low incidence of anomalies. The most common malformations seen on the 10th day involved failure of closure of the neural tube in the head region of the embryo, and various types of anomalies of cardiac rotation and shape. When additional females injected on the 8th day were examined on the 12th day, a high proportion of the fetuses examined had developed exencephaly.A further group of embryos from untreated females were explanted on the 9th day and cultured in vitro in various concentrations of copper sulphate. The lowest levels tested had little obvious effect on neural tube closure. Intermediate doses resulted in, retarded and anomalous embryonic development, while the highest levels employed resulted in neural tube and cardiac anomalies similar to those produced in vivo.The results demonstrate both the direct toxic effect of copper on embryonic development and that the stage of embryonic development at the time of exposure determines both the nature and the extent of the effect.