Correlations of calcium accumulations in arteries, veins, cartilages, ligaments, and bones in single humans

To show the relationships of calcium accumulation in the thoracic aorta to the other tissues, calcium contents were determined with a microwave-induced plasma-atomic emission spectrometer on arteries, veins, cartilages, ligaments, and bones. These tissues were resected from 18 individuals, consisting of 11 men and 7 women who died in the age range 59–91 yr. As thoracic and abdominal aortas are routinely used for radiographic examination of arterial calcification, they appear to be standard tissues of the calcium accumulation. The calcium accumulations were determined in the femoral artery, the superior and inferior venae cavae, the internal jugular vein, cartilages of the articular disk of the temporomandibular joint and the intervertebral disk, both the ligaments of the anterior cruciate ligament and the ligamentum capitis femoris, and the calcaneus, in contrast with the thoracic aorta. As calcium increased in the thoracic aorta, it increased in the femoral artery, the articular disk of the temporomandibular joint, the intervertebral disk, both ligaments of the anterior cruciate ligament, and the ligamentum capitis femoris, but it did not increase in veins, such as the superior and inferior venae cavae and the internal jugular vein. In contrast, it decreased in the calcaneus.     

Contrasting impacts of a native and an invasive exotic shrub on flood‐plain succession

Abstract. Question: How do Coriaria arborea, an N‐fixing native shrub, and Buddleja davidii, a non‐N‐fixing exotic shrub, affect N:P stoichiometry in plants and soils during early stages of primary succession on a flood‐plain? Location: Kowhai River Valley, northeast South Island, New Zealand. Methods: We measured soil and foliar nutrient concentrations, light levels, plant community composition and the above‐ground biomass of Coriaria and Buddleja in four successional stages: open, young, vigorous and mature. Results: Coriaria occurred at low density but dominated above‐ground biomass by the vigorous stage. Buddleja occurred at 5.3 ± 1.0 stems/m² in the young stage and reached a maximum biomass of 520–535 g.m^‐2 during the young and vigorous stages. Mineral soil N increased with above‐ground Coriaria biomass (r²= 0.45), but did not vary with Buddleja biomass. In contrast, soil P increased with Buddleja biomass (r²= 0.35), but not with Coriaria biomass. In early successional stages, 70–80% of the species present were exotic, but this declined to about 15% by the mature stage. Exotic plant species richness declined with increasing Coriaria biomass, but no other measures of diversity varied with either Coriaria or Buddleja biomass. Conclusion: These results demonstrate that Buddleja dominates early succession and accumulates P whereas Coriaria dominates later succession and accumulates N. A key ecosystem effect of the invasive exotic Buddleja is alteration of soil N:P stoichiometry.     

Pb2+在甜菜夜蛾体内的积累及对种群的影响

重金属的污染及其治理是目前倍受关注的生态学问题之一.甜菜夜蛾是我国长江流域及以南地区蔬菜、棉花等作物上的主要害虫,近几年突发趋势明显.本文以甜菜夜蛾为靶标对象,设计5个浓度(0.3、1.2、4.8、19.2、76.8 mg · kg^-1)重金属Pb²⁺处理,探讨处理后甜菜夜蛾各虫态体内Pb²⁺的积累和排泄,并根据甜菜夜蛾各虫态的生长与存活情况,构建了该虫连续3个世代的种群生命表.结果表明: 取食含有不同浓度Pb²⁺的人工饲料后,各虫态甜菜夜蛾体内Pb²⁺的浓度在同一世代不同处理间存在显著差异,且呈显著的剂量 反应关系.各虫态体内Pb²⁺的浓度基本上随胁迫世代数的延长而增加.受Pb²⁺胁迫后,各虫态体内Pb²⁺的浓度顺序为5龄幼虫＞成虫＞蛹;该虫可通过粪便、预蛹蜕和蛹壳排泄体内部分重金属,且粪便和预蛹蜕中的Pb²⁺浓度远大于蛹蜕中的浓度;根据Pb²⁺不同浓度条件下甜菜夜蛾各虫态的存活率、雌性比和产卵量,构建的种群生命表表明,低浓度Pb²⁺胁迫可促进甜菜夜蛾的种群增长,而高浓度胁迫使种群增长衰退;且随着重金属的持续胁迫,其种群衰退更明显.研究结果为长期、客观评价重金属的危害性以及对重要农业害虫的种群影响提供了借鉴.     

Effects of Cadmium,Copper, Lead,and Zinc Contamination on Metal Accumulation by Safflower and Wheat

Accumulation of heavy metals (HMs) in cultivated soils is a continuing environmental problem in many parts of the world. An increase in HM concentration can enhance uptake of toxic metals by crops and enter the human food chain. In this study, the uptake behavior of wheat and safflower was evaluated in a calcareous soil by using 12 undisturbed columns in which half were artificially contaminated. Heavy metals in the form of CdCl₂ (15 mg Cd kg^{? 1}), CuSO₄ (585 mg Cu kg^{? 1}), Pb(NO₃)₂ (117 mg Pb kg^{? 1}), and ZnCl₂ (1094 mg Zn kg^{? 1}) were sprayed on the soil surface and completely mixed in the top 10 cm. The background total concentrations of Cd, Cu, Pb and Zn were 1.6, 29.5, 17.5 and 61.2 mg kg^{? 1}, respectively. After metal application, half of the columns (3 contaminated and 3 uncontaminated) were sown with wheat (Triticum aestivum) and the other half with safflower (Carthamus tinctorious) and grown for 74 days until maturity. After harvesting, soil columns were cut into 10-cm sections and analyzed for HNO₃- and DTPA-extractable metal concentrations. Metal concentrations were also measured in different plant tissues. The results showed that artificial contamination of topsoil decreased the transpiration rate of wheat by 12% and that of safflower by 6%. In contaminated columns, Cd, Cu, Pb, and Zn accumulation in wheat shoot was greater by 8.0-, 1.9-, 3.0-, and 2.1-fold than the control, respectively. Accordingly, these numbers were 46.0-, 1.3-, 1.7-, and 1.6-fold in safflower shoot. Soil contamination with HMs resulted in a 55% decrease in shoot dry matter yield of wheat while it had no significant effect on shoot dry matter of safflower. The normalized water consumption for safflower was therefore not affected by metal contamination (≈ 13 mm H₂O g^{? 1} of dry weight for all safflower and uncontaminated wheat treatments), while contaminated wheat was much less water efficient at about 27 mm H₂O g^{? 1} dry weight. It was concluded that although artificial contamination had a negative effect on wheat growth, it did not affect safflower's normal growth and water efficiency.     

A new screening technique for salinity resistance in rice (Oryza sativa L.) seedlings using bypass flow

A lack of screening techniques delays progress in research on salinity resistance in rice. In this study, we report our test of the hypothesis that an apoplastic pathway (the so-called bypass flow) causes a difference in salt resistance between rice genotypes and can be used in screening for salinity resistance. Fourteen-day-old seedlings of low- and high-Na(+) -transporting recombinant inbred lines (10 of each) of rice IR55178 were treated with 50 mm NaCl and 0.2 mm trisodium-8-hydroxy-1,3,6-pyrenetrisulphonic acid (PTS), a bypass flow tracer, for short (4 d) and long (90 d) periods of time. The results showed that the average shoot Na(+) concentration and bypass flow for high-Na(+) -transporting lines were 1.4 and 2.4 times higher than those of low-Na(+) -transporting lines, respectively. There was a positive linear correlation between the percentage of bypass flow and Na(+) concentrations in the shoots, suggesting that the difference in Na(+) transport in rice is a consequence of different degrees of bypass flow. Moreover, a high correlation was found between bypass flow and seedling survival after prolonged salt stress: the lower the magnitude of bypass flow, the greater the seedling survival. We conclude that bypass flow could be used as a new screening technique for salt resistance in rice.     

Metabolic activation of unsaturated derivatives of valproic acid. Identification of novel glutathione adducts formed through coenzyme A-dependent and -independent processes

The ability of 2-n-propyl-4-pentenoic acid (Δ⁴-VPA) and 2-n-propyl-2(E)-pentenoic acid ([E]-Δ²-VPA), two unsaturated metabolites of valproic acid (VPA), to form reactive intermediates, deplete hepatic glutathione (GSH) and cause accumulation of liver triglycerides was investigated in the rat. With the aid of ionspray liquid chromatography-tandem mass spectrometry (LC-MS/MS), three GSH adducts were detected in the bile of Δ⁴-VPA-treated animals and were identified as 4-hydroxy-5-glutathion-S-yl-VPA-γ-lactone, 5-glutathion-S-yl-(E)-Δ³-VPA and 3-oxo-5-glutathion-S-yl-VPA. A fourth conjugate was identified tentatively as 4-glutathion-S-yl-5-hydroxy-VPA. Quantitative analysis of the corresponding N-acetylcysteine (NAC) conjugates in urine indicated that metabolism of Δ⁴-VPA via the GSH-dependent pathways accounted for approximately 20% of an acute dose (100 mg kg⁻¹ i.p.). In contrast, when rats were given an equivalent dose of (E)-Δ²-VPA, only one GSH adduct (5-glutathion-S-yl-(E)-Δ³-VPA) was detected at low concentrations in bile. In vitro experiments with rat liver mitochondria demonstrated that Δ⁴-VPA undergoes coenzyme A- and ATP-dependent metabolic activation in this organelle via the β-oxidation pathway to intermediates which bind covalently to proteins. When liver homogenates and hepatic mitochondria from rats injected with Δ⁴-VPA, (E)-Δ²-VPA or VPA were analyzed for GSH content, it was found that only Δ⁴-VPA depleted GSH pools significantly. Treatment of rats with Δ⁴-VPA and (to a lesser extent) VPA led to an accumulation of liver triglycerides, whereas (E)-Δ²-VPA had no measurable effect. It is concluded that Δ⁴-VPA undergoes metabolic activation by both microsomal cytochrome P-450-dependent and mitochondrial coenzyme A-dependent processes, and that the resulting electrophilic intermediates, which are trapped in part by GSH, may mediate the hepatotoxic effects of this compound. In contrast, (E)-Δ²-VPA is not transformed to any appreciable extent to reactive metabolites, which thus accounts for the apparent lack of hepatotoxicity of this positional isomer in the rat.     

土壤类型与作物基因型对花生籽实镉积累的影响

以花生主产区的棕壤和潮土为供试土壤,以种植面积最大的白沙1016、花育22和湛油27基因型花生(Arachis hypogaea)为供试作物,采用不添加Cd(对照)和添加Cd(1.5 mg· kg-1)处理进行盆栽试验,研究土壤类型和作物基因型对花生籽实Cd积累的影响.结果表明:两种土壤对照处理的3种基因型花生籽实Cd含量均低于国家食品安全标准,而Cd处理下均高于食品安全标准.同种土壤Cd处理3种基因型花生籽实Cd含量显著高于对照,不同基因型间表现为湛油27＞白沙1016＞花育22,棕壤花生籽实Cd含量及总量均高于潮土.对照处理3种基因型花生籽实Cd生物富集系数均大于1.0,Cd处理下多小于1.0,表明花生籽实对土壤中Cd的累积能力较强,土壤Cd含量进一步增加时,其生物富集能力降低.     

秸秆还田对水稻固碳特性及产量形成的影响

以中浙优1号为材料、秸秆不还田为对照,在大田试验条件下研究了不同秸秆还田量（4000、6000、8000 kg·hm^-2）对水稻群体干物质积累、运转、植株固碳及产量形成的影响. 结果表明： 与对照相比,秸秆还田处理的水稻群体干物质积累总量平均增加63.03 g·m^-2,以6000 kg·hm^-2处理的干物质积累量最高,比对照增加154.40 g·m^-2;在水稻各生育阶段中,秸秆还田处理对分蘖盛期—齐穗期干物质积累的影响最为明显,干物质积累量比对照平均增加71.25 g·m^-2;与对照相比,秸秆还田处理的茎叶干物质输出率和表观转变率分别平均增加4.2%和3.7%,均以6000 kg·hm^-2处理最高,分别为12.8%和11.1%.秸秆还田处理的群体植株固碳量比对照平均增加55.38 g·m^-2,以6000 kg·hm^-2处理的增幅最大,为17.8%;从固碳量在各器官中的分配来看,秸秆还田有利于生育前期茎叶固碳量的积累和生育后期固碳量向穗部的分配.秸秆还田处理的水稻产量比对照平均增加794.59 kg·hm^-2,增幅9.5%,其中6000和4000 kg·hm^-2处理的产量均显著提高,而8000 kg·hm^-2处理的产量增加不显著;从产量构成因素来看,秸秆还田处理单位面积有效穗数的增加是增产的主要原因,平均增加8.4穗·m^-2.     

蔬菜吸收不同形态外源碘的动力学特性

采用水培法,研究了两种蔬菜(小白菜和芹菜)对两种不同形态碘源(I-,IO-3)的吸收和积累特性.结果表明:供试蔬菜吸收碘的速率表现为在短时间(＜60 min)内迅速增加,随着时间的延长蔬菜对碘的吸收速率逐渐下降;在低浓度范围内(0.01～0.50 mg/L)蔬菜对IO-3的吸收速率与碘浓度变化曲线符合饱和吸收动力学特征(表现为遵循酶学方程),进一步研究表明,解偶联剂2,4-二硝基苯酚(DNP)对低浓度(＜0.50 mg/L)下蔬菜IO-3吸收速率具有明显的抑制作用,说明两种蔬菜对低浓度的IO-3可能存在主动吸收,而在高浓度范围内(0.50～10.0 mg/L),蔬菜对碘的吸收速率随着碘浓度的提高呈现直线上升的趋势.两种蔬菜相比,在同样条件下芹菜对碘的吸收速率明显大于小白菜.蔬菜可食部分中碘的含量随着碘浓度的提高而增加,在一次加碘条件下表现为先增加后降低的趋势,而在持续加碘条件下蔬菜中碘的含量在整个处理期间表现为不断增加; Cl-的添加对低浓度下蔬菜碘的吸收具有明显的抑制作用,而随着碘浓度的提高Cl-的抑制作用逐渐减弱.供试蔬菜对碘的富集系数随碘浓度的提高而降低,碘在蔬菜不同器官的分配次序表现为根＞叶＞茎.