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1.
乌江流域不同营养水平水库水体中汞的含量和形态分布   总被引:4,自引:0,他引:4  
为了弄清不同营养状态水库水体的汞含量、形态分布、季节变化及甲基化特征,选取乌江流域富营养状态的乌江渡水库和贫-中营养状态的弓l子渡水库为研究对象,分别于2007年的1月(冬季)、5月(春季)、8月(夏季)和11月(秋季)采集水库水体分层水样及界面水(仅乌江渡水库),分析样品中活性汞(RHg)、总汞(THg)、溶解态汞(DHg)、颗粒态汞(PHg)、总甲基汞(TMeHg)、溶解态甲基汞(DMeHg)和颗粒态甲基汞(PMeHg).结果显示:乌江渡水库THg、DHg、PHg、RHg浓度和引子渡水体中的含量相当,而TMeHg、DMeHg、PMeHg的浓度则显著高于引子渡水库;相对于上覆水体,乌江渡水库底层水体/界面水甲基汞含量明显升高,表明乌江渡水库全年均有甲基化现象发生,而引子渡水库没有发现甲基化现象.以上研究表明,初级生产力水平是水库汞甲基化的重要影响因素.  相似文献   

2.
H3K27 demethylases, at long last   总被引:6,自引:0,他引:6  
Swigut T  Wysocka J 《Cell》2007,131(1):29-32
Methylation of lysine 27 on histone H3 (H3K27me) by the Polycomb complex (PRC2) proteins is associated with gene silencing in many developmental processes. A cluster of recent papers (Agger et al., 2007; De Santa et al., 2007; Lan et al., 2007; Lee et al., 2007) identify the JmjC-domain proteins UTX and JMJD3 as H3K27-specific demethylases that remove this methyl mark, enabling the activation of genes involved in animal body patterning and the inflammatory response.  相似文献   

3.
Physiologic roles of highly phosphorylated inositol phosphates, including those containing pyrophosphate groups, have been the focus of much recent interest. In the April 6, 2007 issue of Science, two papers (Lee et al., 2007; Mulugu et al., 2007) demonstrate the occurrence of a novel inositol pyrophosphate molecule in yeast and elucidate its role in phosphate homeostasis.  相似文献   

4.
Ages, growth and hatch dates of ingressing Brevoortia tyrannus larvae were determined in a 3 year sampling survey at the mouth of the Chesapeake Bay, U.S.A. To determine if otolith‐aged cohorts had variable relative survival, hatch dates of summer‐caught young‐of‐the‐year (YOY) juveniles collected throughout the Chesapeake Bay were compared with hatch dates of ingressing larvae. Modal total length of ingressing larvae was similar among years: 28 mm in 2005–2006 and 2007–2008, and 30 mm in 2006–2007. Ages of ingressing larvae ranged from 9 to 96 days post hatch (dph); mean ages were similar among years, but significantly older in 2006–2007 (50 dph) than in 2005–2006 (44 dph) and 2007–2008 (46 dph). Larval growth rates differed among years. Earliest growth, when larvae were offshore (0–20 dph), was faster in 2006–2007 (0·62 mm day?1), than in 2005–2006 and 2007–2008 (0·55 mm day?1 in these years). Subsequently, from 30 to 80 dph, growth was slowest in 2006–2007. Hatch dates of ingressing larvae occurred from September to March and 90% (2007–2008) to 98% (2006–2007) had hatched prior to 31 December. In contrast, most surviving YOY juvenile B. tyrannus had hatched in January to February, suggesting selective mortality of early‐hatched individuals, apparently during the overwinter, larval to juvenile transition period.  相似文献   

5.
Freitag H  Balke M 《ZooKeys》2011,(136):47-82
Ancyronyx montanussp. n. is described based on adults and larvae, matched using their cox1 DNA sequence data. Larvae of six additional species of Ancyronyx Erichson, 1847 were also described here for the first time, aided by cox1 or cob data: Ancyronyx helgeschneideri Freitag & J?ch, 2007, Ancyronyx minerva Freitag & J?ch, 2007, Ancyronyx patrolus Freitag & J?ch, 2007, Ancyronyx procerus J?ch, 1994, Ancyronyx punkti Freitag & J?ch, 2007, Ancyronyx pseudopatrolus Freitag & J?ch, 2007. Ancyronyx procerus is newly recorded from the Philippines by a larval specimen from Busuanga island. The new species and larval stages are described in detail and illustrated by digital and SEM images. A key to the Ancyronyx larvae of Palawan and an updated checklist of Philippine Ancyronyx is provided.  相似文献   

6.
Virshup DM  Forger DB 《Cell》2007,129(5):857-859
Three recent reports, including one in this issue of Cell, reveal that the circadian regulator CRY is targeted for degradation by the F box E3 ubiquitin ligase FBXL3 (Siepka et al., 2007; Busino et al., 2007; Godinho et al., 2007). These studies confirm the importance of targeted protein degradation as a key design feature of the mammalian circadian clock.  相似文献   

7.
PTEN enters the nuclear age   总被引:7,自引:0,他引:7  
Baker SJ 《Cell》2007,128(1):25-28
Regulation of the PTEN tumor suppressor protein is poorly understood. In this issue, Wang et al. (2007) and Trotman et al. (2007) describe how ubiquitination regulates PTEN stability and its nuclear localization. Additionally, Shen et al. (2007) report that a nuclear pool of PTEN helps to maintain chromosomal stability.  相似文献   

8.
Mighty Piwis defend the germline against genome intruders   总被引:13,自引:0,他引:13  
O'Donnell KA  Boeke JD 《Cell》2007,129(1):37-44
Piwis are a germline-specific subclass of the Argonaute family of RNA interference (RNAi) effector proteins that are associated with a recently discovered group of small RNAs (piRNAs). Recent studies in Drosophila and zebrafish directly implicate Piwi proteins in piRNA biogenesis to maintain transposon silencing in the germline genome (Brennecke et al., 2007; Gunawardane et al., 2007; Houwing et al., 2007). This function may be conserved in mice as loss of Miwi2, a mouse Piwi homolog, leads to germline stem cell and meiotic defects correlated with increased transposon activity (Carmell et al., 2007).  相似文献   

9.
The composition of the ant fauna of a Coral Sea islet, North East Herald Cay, is reported for several years from 1995 to 2007. A major change in composition was first noted in 2007 but probably occurred earlier. Tetramorium lanuginosum, present in 1997 and in previous years, was not found in 2007. Instead, Tetramorium bicarinatum, recorded for the first time in 2006, was abundant in 2007. This change, together with drier conditions, may have initiated a population explosion of a pest coccoid that caused serious damage to the tree, Pisonia grandis. Tetramorium bicarinatum also reduced the abundance of surface-active arthropods compared to their abundance when it was absent. Ants and other invertebrates on three other islets in the Coral Sea are also documented for 2007 and support the dominance effects of T. bicarinatums.  相似文献   

10.
Over 30 years after drainage for agriculture, a 2700 ha temporary marshland was recently restored in Doñana National Park. We describe the recovery of zooplankton communities (copepods, cladocerans and rotifers) in 47 new temporary ponds excavated as part of the restoration project during the first two hydroperiods (April 2006 and 2007), and compare them to those of eight reference sites in the surrounding marshland. Major changes in the species composition and abundance occurred in new ponds between years. While rotifers and cyclopoid copepods dominated in terms of number of individuals in 2006, calanoid copepods and cladocerans were the most abundant groups in 2007. Rotifer species richness was significantly lower in 2007, but there was an increase in Simpson and β-diversity in 2007 owing largely to a dramatic decline in the abundance of Hexarthra cf. fennica (rare in reference sites) from 93% of all rotifer individuals in new ponds in 2006 to only 32% in 2007. In contrast, species richness of copepods and cladocerans was significantly higher in new ponds in 2007, but there were no changes in Simpson diversity. β-Diversity of cladocerans was also significantly higher in 2007. In 2006, the species richness of cladocera and copepods was significantly lower in new ponds than in reference sites, but by 2007 there were no differences in richness or Simpson diversity. Overall, 7 copepod, 13 cladoceran and 26 rotifer taxa were recorded in new ponds, including 80% of taxa recorded in reference sites. These results indicate that zooplankton communities can be rapidly restored in Mediterranean temporary wetlands, at least when large source populations in the surrounding area reduce dispersal limitation. They also illustrate the importance of comparing different metrics of richness and diversity in studies of zooplankton restoration.  相似文献   

11.
Bone remodeling, energy metabolism, and the molecular clock   总被引:4,自引:0,他引:4  
The adult skeleton is constantly renewed through bone remodeling. Four recent papers (Baldock et al., 2007; Lee et al., 2007; Lundberg et al., 2007; Sato et al., 2007) provide new insights into central and peripheral control of this remodeling sequence. Two of the studies add to our knowledge of the complex hypothalamic modulation of bone turnover mediated by NMU and NPY via the sympathetic nervous system, while the other two focus on the peripheral neural target, the osteoblast, and its regulation by neuropeptides and osteocalcin. These findings support a new paradigm concerning the regulation of bone remodeling and provide a foundation for novel approaches to preventing osteoporosis.  相似文献   

12.
The article to which this erratum refers was published in J Cell Biochem (2007) 102: 1130–1139. © 2007 Wiley‐Liss, Inc.  相似文献   

13.
The article to which this erratum refers, J Cell Biochem 2007: 10.1002/jcb.21551 , was originally published online in Wiley InterScience 27 Nov 2007. © 2008 Wiley‐Liss, Inc.  相似文献   

14.
A report of the 2007 EMBO Conference Series on Plant Molecular Biology 'From basic genomics to systems biology', Ghent, Belgium, 2-4 May 2007.  相似文献   

15.
Pan XF  Yang JX  Chen XY  Li ZY 《动物学研究》2011,32(2):196-203
2007—2010年,对滇池金线鲃(Sinocyclocheilus grahami)进行了亲鱼培育、繁殖力和卵径(egg diameter,ED)大小的研究。滇池金线鲃的催产率、核偏位率和孵化率分别由2007年的25.2%、61.5%和30.4%到2010年的91.3%、85.2%和44.5%。四年间这3项指标均有不同程度提高,其中,催产率提高的幅度最大。提供适合滇池金线鲃营养全面的饵料可以保证亲鱼培育的最佳效果,获得高质量的鱼卵和鱼苗。滇池金线鲃绝对怀卵量与体长的关系是F=0.0004826SL3.166(R2=0.6424,P<0.05)。四年来滇池金线鲃的平均产卵量为(2118.4±899.1)粒,平均绝对怀卵量为(2402.9±881.9)粒,平均相对怀卵量为(70.4±20.8)粒。产卵量、绝对怀卵量和相对怀卵量都有随着体长增加而增加的趋势。卵的大小与胚胎存活相关,在胚胎发育的前两天,不同批次胚胎的死亡呈现一种稳定的或低的死亡率;而后5~7d不同大小的卵呈现不同的死亡率,即小的卵具有更高的死亡率;而卵径>2.0mm的胚胎死亡率趋于稳定;大的卵有更高的生存潜力,能保证仔鱼开口前继续完善身体器官的形成或发生所需要的能量。  相似文献   

16.
A report of the 2007 Cold Spring Harbor Laboratory/Wellcome Trust Conference on Functional Genomics and Systems Biology, Hinxton, UK, 10-13 October 2007.  相似文献   

17.
CpG oligodeoxynucleotide induction of antiviral effector molecules in sheep   总被引:3,自引:0,他引:3  
Immunostimulatory CpG oligodeoxynucleotide (ODN) can protect mice against infection by many pathogens but the mechanisms mediating disease protection are not well defined. Furthermore, the mechanisms of CpG ODN induced disease protection in vivo have not been investigated in other species. We investigated the induction of antiviral effector molecules in sheep treated with a class B CpG ODN (2007). Subcutaneous injection of ODN 2007 induced a dose-dependent increase in serum levels of the antiviral effector molecule, 2'5'-A synthetase. Peak levels of enzyme were observed 4 days following ODN injection and enzyme levels remained elevated for the following 3-5 days. Repeated ODN injections induced a more sustained elevation of serum 2'5'-A synthetase activity. Finally, formulation of ODN 2007 in emulsigen increased the level of serum 2'5'-A synthetase activity and this response was CpG-specific. Elevated serum 2'5'-A synthetase activity suggested that CpG ODN acted through the induction of either interferon (IFN)-alpha or IFN-gamma. ODN 2007 did not induce detectable levels of IFN-alpha or IFN-gamma when incubated with peripheral blood mononuclear cells, but both IFN-alpha and IFN-gamma were detected following stimulation of lymph node cells with ODN 2007. CpG ODN induction of 2'5'-A synthetase in vitro correlated with the secretion of both IFN-alpha and IFN-gamma. Furthermore, immunohistochemical staining of skin revealed a marked cellular infiltration at the site of ODN 2007 injection. This cellular infiltration was CpG-specific and consisted of primarily CD172(+) myeloid cells. Many of the cells recruited to the site of ODN 2007 injection expressed IFN-alpha and some IFN-gamma. These observations support the conclusion that localized cell recruitment and activation contribute to CpG ODN induction of antiviral effector molecules, such as interferon and 2'5'-A synthetase.  相似文献   

18.
A backup DNA repair pathway moves to the forefront   总被引:3,自引:0,他引:3  
Nussenzweig A  Nussenzweig MC 《Cell》2007,131(2):223-225
Chromosomal translocations between antigen receptor loci and oncogenes are a hallmark of lymphoid cancers. Several new studies now reveal that programmed DNA breaks created during assembly of antigen receptor genes can be channeled into an alternative DNA end-joining pathway that is implicated in the chromosomal translocations of lymphoid cancers (Corneo et al., 2007; Soulas-Sprauel et al., 2007; Yan et al., 2007).  相似文献   

19.
典型红壤侵蚀景观的时空变化——以福建长汀为例   总被引:2,自引:0,他引:2  
Wu GS  Lin HH  Zhu HJ  Sha JM  Dai WY 《应用生态学报》2011,22(7):1825-1832
基于典型红壤侵蚀区——福建长汀县1988、2000和2007年遥感影像和数字高程模型,获取侵蚀景观类型数据,并利用空间数学模型分析了1988—2007年研究区侵蚀景观格局的变化.结果表明:1988—2007年,研究区不同强度的侵蚀景观类型具有互相转移的特点,主要表现为由侵蚀强度较重的景观向侵蚀强度较轻的景观转移,同时存在少量侵蚀强度较轻景观向侵蚀强度较重景观转移的情形,研究区侵蚀景观空间质心的变化不大,河田镇一直是研究区侵蚀核心区域;研究期间,景观水平的景观格局指数变化反映出研究区景观的低异质性、低破碎化和规则化趋势;斑块水平的景观格局指数变化反映出低侵蚀强度、易治理的斑块整体好转,且合并变大,而高侵蚀强度、难治理的斑块则局部好转而破碎化.  相似文献   

20.
The article to which this erratum refers was published in J Cell Physiol (2007) 210:582–595. J. Cell. Physiol. 215: 285, 2008. © 2007 Wiley‐Liss, Inc.  相似文献   

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