铁过载促进小鼠肝组织发生蛋白质酪氨酸硝化

蛋白质酪氨酸硝化是一种蛋白质翻译后的修饰,其存在会影响酶的催化活性,细胞信号转导和细胞骨架结构．在铁过载情况下,存在引起蛋白质酪氨酸硝化的有利环境,但目前尚无实验证实．本文运用腹腔注射右旋糖苷铁造成小鼠铁过载模型,通过免疫印迹法发现,在铁过载情况下,肝中诱导型一氧化氮合酶表达显著高于正常对照小鼠;铁过载小鼠肝中总体蛋白质硝化程度高于正常小鼠;铁过载引起的蛋白质酪氨酸硝化有一定的选择性,在铁过载小鼠肝中发现一些新的被硝化蛋白质条带（约 57 kD、 35 kD）．上述结果证实,铁过载会促进肝蛋白质酪氨酸硝化．     

Lateralized memory storage and crossed inhibition during odor processing by Limax

After odor conditioning intact Limax maximus and injecting LY into their haemocoel, labeled groups of neurons are found in either the right or left procerebral lobe but never in both procerebral lobes. This suggests that a competitive interaction occurs between right and left odor processing pathways of which the procerebral lobe is a part. We use the nerve discharge in the external peritentacular nerve evoked by applying a puff of conditioned odor to the nose to document crossed inhibition between left and right odor processing pathways. Responses in the external peritentacular nerve evoked by stimulating one superior nose with a conditioned odor are strongly lateralized as responses occur only on the stimulated side. Stimulating both superior noses simultaneously with the same conditioned odor yields responses in both external peritentacular nerves that resemble the sum of responses to unilateral stimulation. Simultaneously stimulating both superior noses, each with a different conditioned odor, leads to strong inhibition of both external peritentacular nerve responses. The crossed inhibition is also evident if both superior and inferior noses on the same side are stimulated simultaneously. A lateral inhibitory mechanism, situated postsynaptic to odor recognition, appears to inhibit external peritentacular nerve responses if the two noses receive conflicting sensory inputs. Accepted: 14 December 1999     

Vitamin A deficiency induces prooxidant environment and inflammation in rat aorta

We evaluated whether nutritional vitamin A deficiency generates oxidative stress and inflammation in aorta. Wistar male rats (21 days old) were given free access to a control (8 mg retinol as retinyl palmitate/kg) or a vitamin A- deficient diet for three months. One group of deficient animals was fed with the control diet fifteen days before sacrifice. Thiobarbituric acid-reactive substances (TBARS) and nitrite concentration where both analyzed in serum and aorta. Aorta Copper-Zinc Superoxide dismutase (CuZnSOD), Glutathion peroxidase (GPx) and Catalase (CAT) activities were measured. In addition, binding activity of the nuclear factor- kB (NF-kB), inducible and endothelial Nitric Oxide synthase (iNOS and eNOS, respectively) and Ciclooxygenase-2 (COX-2) expressions were determinated in aorta. Rats fed the vitamin A- deficient diet were characterized by sub-clinical plasma retinol concentration and showed increased serum and aorta concentrations of TBARS compared to controls. Lower than control activities of CuZnSOD, GPx, and CAT were observed in aorta of the vitamin A- deficient group. The binding activity of NF- kB was higher in vitamin A- deficient animals than controls. In addition, NO production evaluated as nitrite concentration increased in aorta and serum, associated with a higher expression of iNOS, eNOS and COX-2 in aorta of vitamin A-deficient rats. The incorporation of vitamin A into the diet of vitamin A-deficient rats reverted the changes observed in TBARS level, CuZnSOD and GPx activities, nitrite concentration and also, iNOS, eNOS and COX-2 expression. Prooxidant environment and inflammation are induced by vitamin A deficiency in rat aorta.     

2,4-二氯苯酚的矿物表面化学行为研究

矿物质是土壤中的重要组成成分,本实验采用动态反应和平衡反应研究氧化物矿物表面2,4-二氯苯酚(2,4-DCP)的化学行为.结果表明,无定形铁氧化物、针铁矿、α-MnO₂、δ-MnO₂对自然的或外源的有机化合物有较强的氧化能力,其中对2,4二氯苯酚的氧化能力是:δ-MnO₂αMnO₂>无定形铁氧化物、针铁矿.采用分段法估算反应系统的速率,发现氧化锰氧化2,4-二氯苯酚的反应速率是氧化铁的3～50倍,δ-MnO₂氧化2,4-二氯苯酚的速率是α-MnO₂的1.5～3.2倍.根系分泌物由于参与氧化物表面化学反应,对系统2,4-二氯苯酚的氧化过程产生一定影响,α-MnO₂加入根系分泌物后,2,4-二氯苯酚在溶液中的消减速率明显减慢,δ-MnO₂则相反,在根系分泌物共存下溶液中的2,4-二氯苯酚的转化率增加.Cu复合共存可能影响2,4二氯苯酚在矿物表面的键合氧化过程,其中δ-MnO₂对铜吸附能力大于αMnO₂,Cu复合共存对δMnO₂表面2,4-二氯苯酚的氧化影响较大.     

Persistence of hyperbaric oxygen-induced oxidative effects after exposure in rat brain cortex tissue

Hyperbaric oxygen (HBO) causes oxidative stress in several organs and tissues. Due to its high rate of blood flow and oxygen consumption, the brain is one of the most sensitive organs to this effect. Many studies have reported oxidative effects of HBO, but there is no comprehensive data about how long this effect persists. The aim of this study was to elucidate the duration of HBO-induced oxidative/antioxidant action. Male Sprague-Dawley rats were divided into 5 groups. Except for the controls, the animals were subjected to 100% oxygen for 2 h at 3 atm and differed from each other by the time to dissection after exposure that began at 30, 60, 90, or 120 min. Thiobarbituric acid-reactive substances (TBARS), as well as superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity was determined in brain cortex tissue. Additionally, nitrite-nitrate (NO(x)) concentrations were measured. All measured parameters were found to be significantly increased 30 min after exposure. SOD and GSH-Px levels persisted at significantly high levels for 60 min. In conclusion, the oxidative effect of HBO was shown to persist only for 1 h. Further studies should be performed to elucidate the possible molecular interactions during this period.     

Greenhouse gas emissions from a constructed wetland in southern Sweden

This paper investigates the greenhouse gas emissions from a Swedish wetland, constructed to decrease nutrient content in sewage treatment water. To evaluate the effect of the construction in terms of greenhouse gas emissions we carried out ecosystem-atmosphere flux measurements of CO₂, CH₄ and N₂O using a closed chamber technique. To evaluate the importance of vascular plant species composition to gas emissions we distributed the measurement plots over the three dominating plant species at the field site, i.e., Typha latifolia, Phragmites australis and Juncus effusus. The fluxes of CO₂ (total respiration), CH₄ and N₂O from vegetated plots ranged from 1.39 to 77.5 (g m⁻² day⁻¹), −377 to 1387 and −13.9 to 31.5 (mg m⁻² day⁻¹) for CO₂, CH₄ and N₂O, respectively. Presence of vascular plants lead as expected to significantly higher total respiration rates compared with un-vegetated control plots. Furthermore, we found that the emission rates of N₂O and CH₄ was affected by presence of vascular plants and tended to be species-specific. We assessed the integrated greenhouse warming effect of the emissions using a Global Warming Potential over a 100-year horizon (GWP₁₀₀) and it corresponded to 431 kg CO₂ equivalents m⁻² day⁻¹. Assuming a 7-month season with conditions similar to the study period this is equal to 90 tonnes of CO₂ equivalents annually. N₂O emissions were responsible for one third of the estimated total greenhouse forcing. Furthermore, we estimated that the emission from the forested bog that was the precursor land to Magle constructed wetland amounted to 18.6 tonnes of CO₂ equivalents annually. Hence, the constructed wetland has increased annual greenhouse gas emissions by 71.4 tonnes of CO₂ equivalents for the whole area. Our findings indicate that management processes in relation to wetland construction projects must consider the primary function of the wetland in decreasing eutrophication, in relation to other positive aspects on for instance plant and animal life and recreation as well as possible negative climatic aspects of increased emissions of CH₄ and N₂O.     

汉族人群NOS3 A-922G、NOS3 T-786C 与NOS3 G894T SNP的等位基因及其组合分布与高血压的相关性

为了分析汉族人群一氧化氮合酶基因NOS3 A-922G、NOS3 T-786C 与NOS3 G894T单核苷酸多态性（single nucleotide polymorphism,SNP）的等位基因及其组合分布与高血压病的相关性,选取无亲缘关系的高血压病人192例(男97例,女95例)以及无亲缘关系的健康个体122例（男76例,女46例）为对照组,提取静脉血白细胞基因组DNA,采用等位基因特异性引物PCR技术检测NOS3 A-922G、NOS3 T-786C 与NOS3 G894T 3个位点的基因型。其结果显示：高血压病组与对照组NOS3 G894T、NOS3A-922G及NOS3 T-786C各等位基因型及其基因单倍型频率比较无显著性差异(P>0.05)。男、女性别分层研究：无论男亚组还是女亚组均未发现NOS3 A-922G、NOS3 T-786C 与NOS3 G894T各个位点SNP与高血压病有相关性。等位基因组合分布研究发现NOS3 G894G +A-922G+T-786T组合基因型总体频率分布在高血压病组与正常对照组之间有显著性差异(P<0.05,χ2= 4.5944)。男、女性别分层研究：男亚组上述3个位点SNP的各个组合基因型分布频率在高血压病组与正常对照组之间无显著性差异(P>0.05);女亚组中携带NOS3 G894G+A-922G+T-786C 的组合基因型分布频率在高血压病组与正常对照组之间有显著性差异(P<0.01,χ2=8.502)。研究发现,在中国汉族人群中NOS3A–922 G、NOS3 T-786C 与NOS3 G894T SNP与高血压病无明确的相关性,且无性别差异。组合分布研究发现,NOS3 G894G+A-922G+T-786C 的组合基因型分布频率在高血压病女性亚组较健康女性亚组明显减低,提示携带该组合基因型女性人群可能不易患高血压病。     

Influence of Th1/Th2 Cytokines and Nitric Oxide in Murine Systemic Infection Induced by Sporothrix schenckii

In an attempt to elucidate the effects of Sporothrix schenckii infection on the immune response, our laboratory has developed a murine model of disseminated sporotrichosis. Helper T cells can be further subdivided into Th1 and Th2 phenotypes. The differentiation of two subsets of T lymphocytes is driven by IL-12 and IL-4 cytokines, respectively. Th1 cells produce IFN-γ that activate macrophages and promote cell-mediated immunity. In addition, we found low levels of iNOS and NO production in the initial (1st and 2nd weeks) and final (9th and 10th weeks) periods of the infection, in contrast with the period of week 4 to 7 of elevated values. The determination of IFN-γ and IL-12 are in agreement with NO/iNOS detection, showing the presence of cellular immune response throughout the infectious process. However, the production of IL-4 shows an increase in levels after the 5th and 6th weeks suggesting a participation of Th2 response in this period as well. Regarding these results, the study demonstrated that in experimental sporotrichosis infection the cellular immune response participated throughout the period analyzed as a nitric oxide dependent mechanism. In contrast, the presence of Th2 response began in the 5th week, suggesting the participation of humoral immune response in advanced stages of sporotrichosis.     

Retinoic acid and nitric oxide promote cell proliferation and differentially induce neuronal differentiation in vitro in the cnidarian Renilla koellikeri

Retinoic acid (RA) and nitric oxide (NO) are known to promote neuronal development in both vertebrates and invertebrates. Retinoic acid receptors appear to be present in cnidarians and NO plays various physiological roles in several cnidarians, but there is as yet no evidence that these agents have a role in neural development in this basal metazoan phylum. We used primary cultures of cells from the sea pansy Renilla koellikeri to investigate the involvement of these signaling molecules in cnidarian cell differentiation. We found that 9‐cis RA induce cell proliferation in dose‐ and time‐dependent manners in dishes coated with polylysine from the onset of culture. Cells in cultures exposed to RA in dishes devoid of polylysine were observed to differentiate into epithelium‐associated cells, including sensory cells, without net gain in cell density. NO donors also induce cell proliferation in polylysine‐coated dishes, but induce neuronal differentiation and neurite outgrowth in uncoated dishes. No other cell type undergoes differentiation in the presence of NO. These observations suggest that in the sea pansy (1) cell adhesion promotes proliferation without morphogenesis and this proliferation is modulated positively by 9‐cis RA and NO, (2) 9‐cis RA and NO differentially induce neuronal differentiation in nonadherent cells while repressing proliferation, and (3) the involvement of RA and NO in neuronal differentiation appeared early during the evolutionary emergence of nervous systems. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 70: 842–852, 2010