Selenium Distribution in Camel Blood and Organs After Different Level of Dietary Selenium Supplementation

Eight young female camels shared in four groups of two 2 years received a basal diet enriched respectively with 0, 2, 4, and 8 mg selenium under sodium selenite form for 64 days. Feed intake was assessed daily; blood samples were taken on weekly basis. One camel from each group was killed at the end of the experiment. Se concentration in serum was increased significantly in the supplemented groups with an average of 176.3 ± 18.0 ng/mL in the control group, 382.7 ± 107.6 in the group receiving 2 mg Se, 519.8 ± 168.4 in the group receiving 4 mg Se, and 533.4 ± 158.6 in the group receiving 8 mg Se daily. For glutathione peroxidase (GSH-Px) activity, the control group (51.0 IU/g Hb) and the group receiving 2 mg (50.5 IU/g Hb) were significantly different than groups receiving 4 and 8 mg (respectively, 65.9 and 76.1 IU/g Hb). No significant variation occurred for vitamin E (mean, 0.56 ± 0.23 ng/mL). Significant correlation between serum Se and GSH-Px was reported. Kidney was the richest organ in selenium followed by lung, spleen, and liver, but the increase in supplemented groups was more marked in liver and kidney. The hair seemed to be the best indicator of selenium intake in camel.     

钝顶螺旋藻富集转化硒及硒在藻体中的分布

钝顶螺旋藻在４℃、避光、隔离空气条件下,对硒的吸附量死体显著高于活体。藻体对硒的最大富集量为６２７．４μg.g^-1(DW),培养基中硒浓度在３００μg.ml^-1以下时有机硒转化率大于８０％。藻体中的硒主要分布在水溶性组化率大于８０％。藻体中的硒主要分布在水溶性组分中,占总硒的６５％以上,蛋白质硒占有机硒的７１．９％,多糖、核酸也有一定量硒分布。     

Effects of Dietary Form of Selenium on Its Distribution in Eggs

The objective of this experiment was to investigate the selenium distribution in eggs from hens fed diets supplemented with Se from sodium selenite (SS) or selenium-enriched yeast (SY). One-day-old female chickens of Hy-Line Brown breed were randomly divided into four groups according to dietary treatments and, for the subsequent 9?months, were fed diets which differed only in the form or amount of Se supplemented. During the whole experiment, group 1 (control) was fed basal diet (BD) with only background Se level of 0.13?mg/kg dry matter (DM). Diets for groups 2 and 3 consisted of BD supplemented with an Se dose of 0.4?mg/kg DM either in the form of SS or SY, respectively. Group 4 was fed BD supplemented with 0.9?mg Se/kg DM from SY. After 9?months of dietary treatments, the Se levels in egg yolk and albumen from hens fed unsupplemented diet were almost identical whereas eggs from hens given diet supplemented with SS showed significantly higher Se deposition in yolk than in albumen (P?相似文献   

Selenium Species and Their Distribution in Freshwater Fish from Argentina

The distribution and speciation of selenium (Se) in freshwater fish (muscle and liver tissue) from lakes in Argentina was investigated. Three introduced species, brown trout (Salmo trutta), rainbow trout (Oncorhynchus mykiss) and brook trout (Salvelinus fontinalis), and one native species, creole perch (Percichthys trucha), were investigated. Values for total selenium in muscle ranged from 0.66 to 1.61 μg/g, while in the liver, concentrations were much higher, from 4.46 to 73.71 μg/g on a dry matter basis. Separation of soluble Se species (SeCys₂, selenomethionine (SeMet), SeMeSeCys, selenite and selenate) was achieved by ion exchange chromatography and detection was performed by inductively coupled plasma–mass spectrometry. The results showed that in fish muscle, from 47 to 55 % of selenium was soluble and the only Se species identified was SeMet, which represented around 80 % of soluble Se, while in the liver, the amount of soluble Se ranged from 61 to 76 % and the percentage of species identified (SeMet and SeCys₂) was much lower and ranged from 8 to 17 % of soluble Se.     

Absorption,Distribution and Transformation of Selenium in the Tomato plants

Low concentration of selenium enhanced, but high concentration inhibited the growth of tomato seedlings, the higher the concentration of selenium, the more the inhibition of the growth was. Selenium was absorbed quickly by roots, and conveyed to the other organs. With prolonged time, the degree of increase in the distribution of total selenium content in the plants was in the orders of roots>leaves>stems. From lower to upper the distribution of selenium in the leaves increased progressively. At the flowering and bearing stage, the orders of selenium distribution were roots>fruits>stems>leaves. Only a part of selenium in the plants existed at the state of inorganic selenium, and most changed into organic selenium, and the majority of it was in the form of selenoproteins. 90.89% of its selenoproteins was found in the fruits which was more than that of the other organs of plants. Sulfur starvation enhenced the absorption and transportation of selenium from roots,accelerated the distribution of selenium in the leaves ,and increased the organic selenium content in the roots ,stems and fruits.     

Tissue Distribution of Selenium and Effect of Season and Age on Selenium Content in Roe Deer from Northwestern Poland

The aim of the study was to compare selenium concentrations in different organs of roe deer from northwestern Poland. Samples of liver, kidneys, heart and lungs, collected from 74 roe deer shot during the hunting seasons of 2008–2009 in northwestern Poland, were studied. Selenium concentration in the organs was determined spectrofluorimetrically. Mean selenium concentration was 0.06 μg/g w.w. in the liver, 0.41 μg/g w.w. in the kidneys and 0.05 μg/g w.w. in the heart and lungs. Season had a significant effect on selenium concentration in the liver, kidneys, lungs and heart. In all the organs, the highest selenium concentration was found in spring and the lowest in autumn and winter. All animals studied were deficient in selenium. The low selenium concentration in the liver or heart can disturb their function, and in the future, it may be a factor contributing to the population decline of roe deer in the northwestern part of Poland.     

鲁西地区蛇类的分布格局

以山东聊城分布的7种蛇类作为研究对象,探讨了鲁西平原区蛇类的群落结构和分布格局.结果 表明,该区蛇类平均分布密度较高的是白条锦蛇Elaphe dione、赤链蛇Dinodon rufozonatum和虎斑颈槽蛇大陆亚种Rhabdophis tigrina lateralis.多数蛇类倾向于选择湿地周边、边缘富有灌草丛的农田区以及有丰富草被的居民区等为栖息地,该区蛇类的栖息地选择有着显著的不重叠性.     

Distribution Pattern of Serotoninergic Neurons in Trematode Cercariae

The review summarizes data on the number, size and localization of serotoninergic neurons in cercariae of 16 trematode species, referring to 11 families. Presented diagrams show distribution patterns of serotoninergic neurons in cercariae of trematodes from different taxonomic, biological and morphological groups. Data analysis indicates that the number, disposition and size of these neurons vary in cercariae of different species. The data are discussed in relation with a functional significance of serotonin as a neurotransmitter in free-living larvae—trematode cercariae.     

上海市树附生苔藓植物分布格局研究

在对上海市18个样点的树附生苔藓植物种类与盖度样方调查基础上,报道了43种树附生苔藓植物,其中藓类39种,苔类4种.根据盖度值应用双向指示种分析法(TW IN SPAN)和除趋势对应分析(DCA)对其分布格局进行了分析.结果表明,上海市树附生苔藓植物可聚类为4个样点组:样点组Ⅰ为7个样点,6个位于市中心,共有树附生苔藓16种,总盖度为12.43%;样点组Ⅱ为市郊样地年龄较年轻的4个样点,共有树附生苔藓11种,总盖度最小为8.47%;样点组Ⅲ为市郊6个样点,共有树附生苔藓33种,总盖度为25.82%;样点组Ⅳ为佘山自然保护区一处,共有树附生苔藓10种,总盖度为26.42%.结果反映了城市树附生苔藓植物分布与不同生境、环境污染及人为干扰有一定的相关性.     

CpG Distribution and Methylation Pattern in Porcine Parvovirus

Based on GC content and the observed/expected CpG ratio (oCpGr), we found three major groups among the members of subfamily Parvovirinae: Group I parvoviruses with low GC content and low oCpGr values, Group II with low GC content and high oCpGr values and Group III with high GC content and high oCpGr values. Porcine parvovirus belongs to Group I and it features an ascendant CpG distribution by position in its coding regions similarly to the majority of the parvoviruses. The entire PPV genome remains hypomethylated during the viral lifecycle independently from the tissue of origin. In vitro CpG methylation of the genome has a modest inhibitory effect on PPV replication. The in vitro hypermethylation disappears from the replicating PPV genome suggesting that beside the maintenance DNMT1 the de novo DNMT3a and DNMT3b DNA methyltransferases can’t methylate replicating PPV DNA effectively either, despite that the PPV infection does not seem to influence the expression, translation or localization of the DNA methylases. SNP analysis revealed high mutability of the CpG sites in the PPV genome, while introduction of 29 extra CpG sites into the genome has no significant biological effects on PPV replication in vitro. These experiments raise the possibility that beyond natural selection mutational pressure may also significantly contribute to the low level of the CpG sites in the PPV genome.     

In Situ Speciation and Distribution of Toxic Selenium in Hydrated Roots of Cowpea

The speciation and spatial distribution of selenium (Se) in hydrated plant tissues is not well understood. Using synchrotron-based x-ray absorption spectroscopy and x-ray fluorescence microscopy (two-dimensional scanning [and associated mathematical model] and computed tomography), the speciation and distribution of toxic Se were examined within hydrated roots of cowpea (Vigna unguiculata) exposed to either 20 µm selenite or selenate. Based upon bulk solution concentrations, selenate was 9-fold more toxic to the roots than selenite, most likely due to increased accumulation of organoselenium (e.g. selenomethionine) in selenate-treated roots. Specifically, uptake of selenate (probably by sulfate transporters) occurred at a much higher rate than for selenite (apparently by both passive diffusion and phosphate transporters), with bulk root tissue Se concentrations approximately 18-fold higher in the selenate treatment. Although the proportion of Se converted to organic forms was higher for selenite (100%) than for selenate (26%), the absolute concentration of organoselenium was actually approximately 5-fold higher for selenate-treated roots. In addition, the longitudinal and radial distribution of Se in roots differed markedly: the highest tissue concentrations were in the endodermis and cortex approximately 4 mm or more behind the apex when exposed to selenate but in the meristem (approximately 1 mm from the apex) when exposed to selenite. The examination of the distribution and speciation of Se in hydrated roots provides valuable data in understanding Se uptake, transport, and toxicity.Selenium (Se) is an essential micronutrient for humans and other animals (Rayman, 2008). At elevated concentrations, however, it is toxic, and the concentration range from deficiency to lethality is unusually narrow (Terry et al., 2000). Plants represent a direct entrance to the wider food chain as the main sources of dietary Se (Rayman, 2008). The uptake and accumulation of Se by plants is an important process in controlling the health risks resulting from Se deficiency or toxicity. Se toxicity to plants has been observed in arid and semiarid soils derived from seleniferous rocks and shales, although anthropogenic contamination is also of concern (Terry et al., 2000). Therefore, it is important that the mechanisms of Se uptake, transformation, and toxicity in plants are understood in order to reduce health risks.Selenite (Se[IV]) and selenate (Se[VI]) are the two dominant inorganic species in soils depending upon the redox potential and pH (Elrashidi et al., 1987). The mechanism of Se[VI] uptake is well known: it is taken up by plant roots via the high-affinity sulfate transporters (Terry et al., 2000) due to the similarity between Se[VI] and sulfate. By contrast, little is known about the uptake mechanism involved in Se[IV] in plant roots. Some studies suggested that Se[IV] is taken up via passive diffusion (Shrift and Ulrich, 1969; Arvy, 1993). Recently, Zhao et al. (2010) reported that the uptake of Se[IV] is mediated by the silicon (Si) influx transporter Lsi1 (OsNIP2;1) in rice (Oryza sativa). Furthermore, Se[IV] uptake was found to occur via both passive diffusion and phosphate transporters in the marine coccolithophore Emiliania huxleyi (Araie et al., 2011). Apart from the difference in their mechanisms of uptake, they also differ in their mobility within plants (Li et al., 2008). Se[VI] is relatively easily translocated from roots to shoots, whereas Se[IV] tends to accumulate within the roots (Arvy, 1993). Despite this important progress, much less is known about the sites of uptake of Se[IV]/Se[VI] and their possible chemical transformations in hydrated plant roots. This information regarding the in situ distribution and chemical forms of Se would be helpful in elucidating the mechanism(s) responsible for Se uptake, transformation, and toxicity in plants.Recent advances in synchrotron-based techniques allow in situ measurement of the distribution of metal(loid)s in hydrated fresh plant tissues (Kopittke et al., 2011, 2012; Lombi et al., 2011a). In particular, the prototype Maia detector system, jointly developed by the Australian Synchrotron, the Commonwealth Scientific and Industrial Research Organization, and the Brookhaven National Laboratory, represents a new-generation x-ray fluorescence detector and real-time processing approach that provides unprecedented capabilities in in situ element imaging and measurement (Lombi et al., 2011b). The Maia uses an annular array of 384 silicon-diode detectors positioned in a backscatter geometry to subtend a large solid angle (approximately 1.3 steradian) and to achieve high count-rate capacity (Kirkham et al., 2010). Data acquisition times are approximately 10 to 100 times faster in the Maia than for other detectors, thereby allowing analysis of highly hydrated biological specimens (e.g. roots) without observable damage (Lombi et al., 2011a). This has allowed us to overcome the analytical challenges of examining the two-dimensional and virtual three-dimensional distribution of low-concentration metal(loid)s in hydrated and fresh plant tissues (Kopittke et al., 2011, 2012; Lombi et al., 2011a, 2011c).In this study, we investigated the speciation and quantified the longitudinal and radial distribution of Se in hydrated roots of cowpea (Vigna unguiculata) exposed to either Se[IV] or Se[VI]. Cowpea is a model species of rhizotoxicity and is also one of the most important food legume crops in the semiarid tropics, where Se toxicity is often a concern. The chemical forms of Se in cowpea roots were first examined using x-ray absorption spectroscopy (XAS). Second, with x-ray fluorescence microscopy (µ-XRF), we used two-dimensional imaging (coupled with an associated mathematical model to calculate concentrations of Se within various tissues of the root cylinder) to determine the spatially resolved distribution of Se within root tissues. Additionally, sequential tomography was used to provide virtual three-dimensional reconstructions of Se distribution in roots, enabling comparison of computed tomography with the mathematical model.     

银杉种群的空间分布格局

银杉（ＣａｔｈａｙａａｒｇｙｒｏｐｈｙｌｌａＣｈｕｎｅｔＫｕａｎｇ）种群的空间分布格局受银杉种群本身的生物学特性、种群的年龄和更新方式等及群落内小环境的共同影响。在老龄种群内,多表现为集群分布;在较年轻的种群内,多为随机分布。气候和立地条件基本一致时,群落内岩石的覆盖与土壤蚀形成的小环境。     

中国有尾两栖类地理分布格局与扩散路线

通过绘制我国有尾两栖类的地理分布图,分析该类群的地理分布格局与可能的起源和扩散路线。研究结果表明,有尾两栖类在我国的地理分布格局,有三个关键区域:1.位于长江上游的、有尾两栖类物种丰富度最高的横断山区,是有尾两栖类的分布中心,该区域很可能亦为有尾两栖类的起源中心及主要特化中心;2.三个次级分布与特化中心,大别山-淮河流域区、南岭-珠江流域区、浙闽山地-江南水乡区;3.四个小型的三级分布与特化中心,台琼海岛区、东北长白山-三江流域区、秦巴山地-汉江渭河流域区、天山-伊犁河流域区。另外,该类群可能的迁移和扩散路线可归纳为:沿着各水系,从分布中心分别向东西南北四个方向迁移和扩散,其中以向北和向东为主,向南和向西扩散的种类较少。向北扩散的主要是小鲵科(Hynobiidae)的一些种类,向东扩散的种类则以蝾螈科(Salamandridae)物种为主。广布于我国东部的隐鳃鲵科(Cryptobranchidae)种类,极可能是该类群向北和向东这两个方向扩散的结果。研究结果表明,东亚两栖动物区系具有明显的整体性,即东亚两栖动物区系是单源的、本地起源的。本项研究结果支持中国日本界假说。     

An Agar-diffusion Technique Applied to the Study of Gibberellins in Tomato (Lycopersicon esculentumMill.) Plants

Chromatography of extracts of agar blocks on which shoot tipsof tomato had stood for 24 h revealed the presence of at leasttwo gibberellin-like substances. Gibberellin-like activity detectedby the dwarf pea bioassay was shown to be associated with activityin promoting elongation growth in tomato seedlings. The activesubstances were acidic; tests for the presence of ‘neutral’,‘basic’ and ‘bound’ gibberellins inextracts of the agar blocks gave negative results. Amounts ofgibberellin-like substances obtained from the shoot tips wereincreased by the incorporation of EDTA into the agar blocksbut were apparently unaffected by the temperature (within therange 5–25 °C) at which the diffusion was carriedout. It is suggested that the technique measured levels of diffusiblegibberellins in the tissues at the time of their excision ratherthan rates of gibberellin synthesis during the diffusion period.     

Distribution of Selenium in Bovine Milk and Selenium Deficiency in Rats Fed Casein-based Diets,Monitored by Lipid Peroxide Level and Glutathione Peroxidase Activity

A major proportion of selenium in bovine milk was found in fluorometric analysis to be associated with the casein fraction, largely in alkali-labile form, and the rest with the whey fraction mostly in free selenite form. This uneven distribution of milk selenium seems to provide an explanation for selenium deficiency in purified caseins. The activity of glutathione peroxidase, a selenoprotein, in the liver of growing male rats fed ad libitum low-selenium diets containing either vitamin-free casein or Torula yeast 0.065 ± 0.012 or 0.015 ± 0.004 μ g Se/g diet, respectively) for 3 weeks decreased to 4 to 6% of that of the control rats fed a commercial stock diet (0.185 ± 0.092 μ g Se/g diet). Selenium status was evaluated by three different parameters for the rats assigned under pair-feeding regimen to those vitamin-free casein-based diets which were supplemented with graded levels of selenium as sodium selenite. The hepatic levels of the thiobarbituric acid-reactive substance, an indication of lipid peroxidation, decreased to control level with selenium supplementation per g diet of 0.1 μ g and over. The hepatic glutathione peroxidase activity reached a plateau above a 0.1 μ g/g diet of selenium supplementation, whereas the erythrocyte enzyme activity increased with increasing levels of supplementary selenium. These results support the notion that semi-purified diets containing vitamin-free casein as a prime protein source would not satisfy the selenium requirement of growing animals unless deliberately supplemented with additional selenium.     

硒、谷胱甘肽过氧化物酶和不饱和脂肪酸在鼠脑亚细胞中的分布

采用梯度离心和放射性同位素等方法从鼠脑中分离得到髓磷脂、突触囊、轻突触体、重突触体、线粒体６个亚细胞组分。分别测定了各亚细胞中硒－７５、谷胱甘肽过氧化物酶和不饱和脂肪酸的含量,结果表明这些成分在鼠脑亚细胞中的分布呈现明显的相关性,同时首次在突触囊、线粒体和微粒体中检测到三种不同的谷胱甘肽过氧化物酶的活性峰,其中之一可能是红细胞谷胱甘肽过氧化物酶（ＥＣ１．１１．１．９）．还就机体的自我保护机制和硒在脑组织中的重要作用进行了讨论。     

中国硬叶兜兰地理分布格局及其潜在分布区预测

该研究基于MaxEnt模型和ArcGIS技术,采用实地调查为主结合标本、文献查阅的方法得到全国107个硬叶兜兰有效分布点,并筛选出13个因子,从生态位模型角度对其潜在地理分布进行预测,并采用AUC值对模型进行准确性检验,用ArcGIS 10.6软件进行可视化处理,分析硬叶兜兰潜在分布区并计算面积;采用刀切法、预测因子贡献率和响应曲线,分析影响硬叶兜兰分布的主导因子,为硬叶兜兰的就地保护、迁地保护、野外回归和开发利用提供理论区划依据。结果表明：(1)硬叶兜兰在全国大尺度上总体呈零散分布,以滇、黔、桂三省(自治区)的喀斯特山地为主要分布区;小尺度上普遍呈现出微地形小居群聚集分布的特点,有64.95%的分布点实际分布面积不超过100 m²。(2)该种潜在分布区预测的构建数据和检验数据AUC值分别为0.992和0.987,其潜在分布区为贵州西南至南部地区、贵州中部地区、云南东南部、广西北部至西北部,其中最适宜区为滇东南、黔西南至桂西北地区,面积约3 912.71 km²。(3)影响硬叶兜兰潜在分布的主导因子及最适范围是顶层土壤质地(壤土)、最干季度降水量(55~85 mm)、年均降水量(1 220~1 480 mm)、碳酸钙含量(2.5%~2.7%),4个主导因子的贡献率分别为30.0%、20.1%、16.2%和7.0%。研究认为,硬叶兜兰被采挖严重,对生境要求严格,结合该种在中国的实际分布情况、生存现状、受威胁状况和潜在分布区预测结果,建议将硬叶兜兰列入国家重点保护植物名录,并通过自然保护区或保护小区等方式加强原生地保护。     

云贵鹅耳枥种群分布格局的分形特征

应用分形理论中的计盒维数和信息维数探讨了贵阳喀斯特山地贵鹅耳枥种群分布格局的分形特征。结果表明,贵鹅耳枥种群的分布格局具有分形特征,其计盒维数为1．1853－1．7419,信息维数为1．1961－1．7051。集群型的贵鹅耳枥种群的计盒维数和信息维数均比随机型的高。计盒维数定量地反映了贵鹅耳枥种群占据生态空间的能力,信息维数则揭示了该种群格局强度的尺度变化程度和表征了种群个体分布的非均匀性。这两种维数方法都适用于贵鹅耳枥种群分布格局分形特征的定量描述。