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1.
Displaced starburst amacrine cells (SACs) are retinal interneurons that exhibit GABA A receptor-mediated and Cl ? cotransporter-mediated, directionally selective (DS) light responses in the rabbit retina. They depolarize to stimuli that move centrifugally through the receptive field surround and hyperpolarize to stimuli that move centripetally through the surround (Gavrikov et al, PNAS 100(26):16047–16052, 2003, PNAS 103(49):18793–18798, 2006). They also play a key role in the activity of DS ganglion cells (DS GC; Amthor et al, Vis Neurosci 19:495–509 2002; Euler et al, Nature 418:845–852, 2002; Fried et al, Nature 420:411– 414, 2002; Gavrikov et al, PNAS 100(26):16047–16052, 2003, PNAS 103(49):18793–18798, 2006; Lee and Zhou, Neuron 51:787–799 2006; Yoshida et al, Neuron 30:771–780, 2001). In this paper we present a model of strong DS behavior of SACs which relies on the GABA-mediated communication within a tightly interconnected network of these cells and on the glutamate signal that the SACs receive from bipolar cells (a presynaptic cell that receives input from cones). We describe how a moving light stimulus can produce a large, sustained depolarization of the SAC dendritic tips that point in the direction that the stimulus moves (i.e., centrifugal motion), but produce a minimal depolarization of the dendritic tips that point in the opposite direction (i.e., centripetal motion). This DS behavior, which is quantified based on the relative size and duration of the depolarizations evoked by stimulus motion at dendritic tips pointing in opposite directions, is robust to changes of many different parameter values and consistent with experimental data. In addition, the DS behavior is strengthened under the assumptions that the Cl? cotransporters Na?+?-K?+?-Cl?? and K?+?-Cl?? are located in different regions of the SAC dendritic tree (Gavrikov et al, PNAS 103(49):18793–18798, 2006) and that GABA evokes a long-lasting response (Gavrikov et al, PNAS 100(26):16047–16052, 2003, PNAS 103(49):18793–18798, 2006; Lee and Zhou, Neuron 51:787–799, 2006). A possible mechanism is discussed based on the generation of waves of local glutamate and GABA secretion, and their postsynaptic interplay as the waves travel between cell compartments.  相似文献   

2.
MYH9 has been proposed as a major genetic risk locus for a spectrum of nondiabetic end stage kidney disease (ESKD). We use recently released sequences from the 1000 Genomes Project to identify two western African-specific missense mutations (S342G and I384M) in the neighboring APOL1 gene, and demonstrate that these are more strongly associated with ESKD than previously reported MYH9 variants. The APOL1 gene product, apolipoprotein L-1, has been studied for its roles in trypanosomal lysis, autophagic cell death, lipid metabolism, as well as vascular and other biological activities. We also show that the distribution of these newly identified APOL1 risk variants in African populations is consistent with the pattern of African ancestry ESKD risk previously attributed to MYH9. Mapping by admixture linkage disequilibrium (MALD) localized an interval on chromosome 22, in a region that includes the MYH9 gene, which was shown to contain African ancestry risk variants associated with certain forms of ESKD (Kao et al. 2008; Kopp et al. 2008). MYH9 encodes nonmuscle myosin heavy chain IIa, a major cytoskeletal nanomotor protein expressed in many cell types, including podocyte cells of the renal glomerulus. Moreover, 39 different coding region mutations in MYH9 have been identified in patients with a group of rare syndromes, collectively termed the Giant Platelet Syndromes, with clear autosomal dominant inheritance, and various clinical manifestations, sometimes also including glomerular pathology and chronic kidney disease (Kopp 2010; Sekine et al. 2010). Accordingly, MYH9 was further explored in these studies as the leading candidate gene responsible for the MALD signal. Dense mapping of MYH9 identified individual single nucleotide polymorphisms (SNPs) and sets of such SNPs grouped as haplotypes that were found to be highly associated with a large and important group of ESKD risk phenotypes, which as a consequence were designated as MYH9-associated nephropathies (Bostrom and Freedman 2010). These included HIV-associated nephropathy (HIVAN), primary nonmonogenic forms of focal segmental glomerulosclerosis, and hypertension affiliated chronic kidney disease not attributed to other etiologies (Bostrom and Freedman 2010). The MYH9 SNP and haplotype associations observed with these forms of ESKD yielded the largest odds ratios (OR) reported to date for the association of common variants with common disease risk (Winkler et al. 2010). Two specific MYH9 variants (rs5750250 of S-haplotype and rs11912763 of F-haplotype) were designated as most strongly predictive on the basis of Receiver Operating Characteristic analysis (Nelson et al. 2010). These MYH9 association studies were then also extended to earlier stage and related kidney disease phenotypes and to population groups with varying degrees of recent African ancestry admixture (Behar et al. 2010; Freedman et al. 2009a, b; Nelson et al. 2010), and led to the expectation of finding a functional African ancestry causative variant within MYH9. However, despite intensive efforts including re-sequencing of the MYH9 gene no suggested functional mutation has been identified (Nelson et al. 2010; Winkler et al. 2010). This led us to re-examine the interval surrounding MYH9 and to the detection of novel missense mutations with predicted functional effects in the neighboring APOL1 gene, which are significantly more associated with ESKD than all previously reported SNPs in MYH9.  相似文献   

3.
Friedreich ataxia (FRDA), an autosomal recessive neurological dysfunction that severely impairs motor coordination and reduction of life expectancy in humans, is caused by a deficiency in frataxin, a nuclear-encoded mitochondrial protein. Recently, a frataxin ortholog has been identified in Arabidopsis thaliana, named AtFH, with a transit peptide for localization in mitochondria and 65% sequence identity with human frataxin (Busi et al. FEBS Lett 576:141–144, 2004). Complementation of S. cerevisiae mutant strain Δyfh1 deficient in frataxin with AtFH, proved that the plant isoform is a functional protein, able to restore normal respiration and growth rates in the mutant yeast (Busi et al. FEBS Lett 576:141–144, 2004). AtFH is localized in mitochondria as its animal counterparts (Busi et al. Plant J 48:873–882, 2006); it is expressed mainly in flowers and developing embryos and it is an essential protein, since the knocking out of AtFH gene causes arrest of embryo development at the globular stage (Vazzola et al. FEBS Lett 581:667–672, 2007). A T-DNA insertional A.thaliana mutant showing a greater than 50% reduction of AtFH protein content, named atfh-1, has impaired activity of two mitochondrial enzymes possessing [Fe-S] clusters: aconitase and succinate dehydrogenase (Busi et al. Plant J 48:873–882, 2006). The results obtained in the last ten years on animal systems can contribute, without any doubt, to the elucidation of the role of frataxin in plant mitochondria; however, mitochondria of photosynthetically active cells, differently from animal ones, are not the major source of Reactive Oxygen Species (ROS) which could suggest possible differences in function between plant and animal frataxin.  相似文献   

4.
Heckerocrinus nom. nov., a new generic name of fossil Ordovician crinoid, is proposed for preoccupied fossil generic name Bockia Hecker 1940 non Reisinger 1924 [Vermes: Turbellaria??Typhloplanidae-Protoplanellinae]. Illegitimate family name Bockiidae Ubaghs 1972 is replaced with a new valid family name Heckerocrinidae nom. nov.  相似文献   

5.
Objectives The “K-10” [9] represents an internationally accepted self-assessment instrument for psychological distress. A German translation of the questionnaire is presented and its construct properties are evaluated. In addition, the receiver operator characteristic’s are assessed. Methods Psychometric testing was performed in a sample of 600 psychotherapeutic outpatients and 341 medical students. Convergent validity was assessed in relation to the BSI [5] and STAI [10]. Results The internal consistency of the instrument (Cronbachs Alpha 0.90 – 0.80) and the convergent validity were satisfactory. Validity of the K-10 regarding the detection of mental disorders was compared using ROC analysis with areas under the curve (AUC = 0.88). Conclusion We conclude that the German version of the K-10 represents a useful and reliable screening and research instrument for the assessment of psychological distress.  相似文献   

6.
7.
An efficient large-scale clonal propagation protocol has been described for Withania somnifera (L.) Dunal, a valuable medicinal plant, using cotyledonary nodes derived from axenic seedlings. Murashige and Skoog’s (Physiol Plant 15:473–497, 1962) (MS) medium supplemented with 1.0 mg l?1 N 6-benzyladenine (BA) was found to be optimum for production of multiple shoots (100 % shoot proliferation frequency and 16.93 shoots per explant). Successive shoot cultures were established by repeatedly sub-culturing the original cotyledonary node on a fresh medium after each harvest of newly formed shoots. Multiple shoot proliferation was also achieved from nodal segments derived from in vitro raised shoots on MS medium augmented with 1.0 mg l?1 BA. Regenerated shoots were best rooted (95.2 %, 38.7 roots per shoot) in half-strength MS medium supplemented with 1.0 mg l?1 indole-3-butyric acid. The plantlets were successfully acclimated and established in soil. Random amplified polymorphic DNA and inter-simple sequence repeats analysis revealed a homogeneous amplification profile for all micropropagated plants analyzed validating the genetic fidelity of the in vitro regenerated plants.  相似文献   

8.
The occurrence of two alien alpheid shrimps of the genus Athanas Leach, 1814 [in Leach 1813–1814], the Indo-West Pacific A. dimorphus Ortmann, 1894 and the Eastern Atlantic A. nitescens (Leach, 1813 [in Leach 1813–1814]), on the coast of the state of S?o Paulo, Brazil, is reported. The presence of A. dimorphus extends the range of this species in the western Atlantic farther to the south in Brazil, whereas A. nitescens is reported for the first time in the western Atlantic, representing the second alien alpheid species on this side of the Atlantic and the twenty-first decapod crustacean introduced in Brazil. We provide morphological accounts of the material examined and illustrate the most important diagnostic characters of both species. An overview of the possible mechanisms of their introduction on the coast of S?o Paulo is also provided.  相似文献   

9.
AIDS-associated, CCR5-tropic (R5) HIV-1 clones, isolated from a patient that never developed CXCR4-tropic HIV-1, replicate to a greater extent and cause greater cytopathic effects than R5 HIV-1 clones isolated before the onset of AIDS. Previously, we showed that HIV-1 Env substantially contributed to the enhanced replication of an AIDS clone. In order to determine if Nef makes a similar contribution, we cloned and phenotypically analyzed nef genes from a series of patient ACH142 derived R5 HIV-1 clones. The AIDS-associated Nef contains a series of residues found in Nef proteins from progressors [1]. In contrast to other reports [13], this AIDS-associated Nef downmodulated MHC-I to a greater extent and CD4 less than pre-AIDS Nef proteins. Additionally, all Nef proteins enhanced infectivity similarly in a single round of replication. Combined with our previous study, these data show that evolution of the HIV-1 env gene, but not the nef gene, within patient ACH142 significantly contributed to the enhanced replication and cytopathic effects of the AIDS-associated R5 HIV-1 clone.  相似文献   

10.
The Peruvian plant Lepidium meyenii (Maca) has been shown to possess neuroprotective activity both in vitro and in vivo [13]. Previous studies have also demonstrated the activity of the pentane extract and its macamides, the most representative lipophilic constituents of Maca, in the endocannabinoid system as fatty acid amide hydrolase (FAAH) inhibitors. One of the most active macamides, N-3-methoxybenzyl-linoleamide [4, 5], was studied to determine its mechanism of interaction with FAAH and whether it has inhibitory activity on mono-acyl glycerol lipase (MAGL), the second enzyme responsible for endocannabinoid degradation [6]. Macamide concentrations from 1 to 100 μM were tested using FAAH and MAGL inhibitor assay methods and showed no effect on MAGL. Tests with other conditions were performed in order to characterize the inhibitory mechanism of FAAH inhibition. N-3-methoxybenzyl-linoleamide displayed significant time-dependent and dose-dependent FAAH inhibitory activity. The mechanism of inhibition was most likely irreversible or slowly reversible. These results suggest the potential application of macamides isolated from Maca as FAAH inhibitors, as they might act on the central nervous system to provide analgesic, anti-inflammatory, or neuroprotective effects, by modulating the release of neurotransmitters.  相似文献   

11.
Following a strategy similar to that used in baker’s yeast (Herrgård et al. Nat Biotechnol 26:1155–1160, 2008). A consensus yeast metabolic network obtained from a community approach to systems biology (Herrgård et al. 2008; Dobson et al. BMC Syst Biol 4:145, 2010). Further developments towards a genome-scale metabolic model of yeast (Dobson et al. 2010; Heavner et al. BMC Syst Biol 6:55, 2012). Yeast 5—an expanded reconstruction of the Saccharomyces cerevisiae metabolic network (Heavner et al. 2012) and in Salmonella typhimurium (Thiele et al. BMC Syst Biol 5:8, 2011). A community effort towards a knowledge-base and mathematical model of the human pathogen Salmonella typhimurium LT2 (Thiele et al. 2011), a recent paper (Thiele et al. Nat Biotechnol 31:419–425, 2013). A community-driven global reconstruction of human metabolism (Thiele et al. 2013) described a much improved ‘community consensus’ reconstruction of the human metabolic network, called Recon 2, and the authors (that include the present ones) have made it freely available via a database at http://humanmetabolism.org/ and in SBML format at Biomodels (http://identifiers.org/biomodels.db/MODEL1109130000). This short analysis summarises the main findings, and suggests some approaches that will be able to exploit the availability of this model to advantage.  相似文献   

12.
The taxonomy of the Atlantic and Eastern Pacific species of Kyphosus is reviewed with K. bosquii (Lacepède 1802), K. incisor (Cuvier 1831), K. analogus (Gill 1862) and K. elegans (Peters 1869) considered valid, and K. atlanticus sp. nov. newly described. Kyphosus bosquii and K. atlanticus are both characterized by 12 dorsal- and 11 anal-fin soft rays, but differ in the number of longitudinal scale rows along the midbody (61–66, mode 63 vs. 50–56, mode 54). Kyphosus incisor and K. analogus, characterized by 14 dorsal- and 13 anal-fin soft rays, similarly differ from each other in midbody longitudinal scale row counts (57–64, mode 60 vs. 68–74, mode 70 or 72). Kyphosus elegans is characterized by 13 dorsal- and 12 anal-fin soft rays, and 51–57 midbody longitudinal scale rows. Kyphosus bosquii, K. atlanticus and K. incisor are distributed in the Atlantic Ocean, K. analogus and K. elegans occurring in the Eastern Pacific. The holotype of Pimelepterus flavolineatus Poey 1866, here regarded as a junior synonym of K. incisor, was located within a collection of Cuban fishes donated to the Smithsonian Institution by Poey in 1873. A neotype is designated here for K. analogus. Pimelepterus gallveii Cunningham 1910, Kyphosus palpebrosus Miranda-Ribeiro 1919 and K. metzelaari Jordan and Evermann 1927 are recognized as junior synonyms of K. bosquii. Pimelepterus sandwicensis Sauvage 1880 is a junior synonym of K. elegans. Perca saltatrix Linnaeus 1758, together with the replacement name Perca sectatrix Linnaeus 1766, is regarded as nomina dubia.  相似文献   

13.
The development of new anti-neoplastic drugs is a key issue for cancer chemotherapy due to the reality that, most likely, certain cancer cells are resistant to current chemotherapy. The past two decades have witnessed tremendous advances in our understanding of the pathogenesis of cancer. These advances have allowed identification new targets as oncogenes, tumor supressor genes and the possible implication of the mitochondria (Fulda et al. Nat Rev Drug Discov 9:447–464, 2010). Annonaceous Acetogenins (ACGs) have been described as the most potent inhibitors of the respiratory chain because of their interaction with mitochondrial Complex I (Degli Esposti and Ghelli Biochim Biophys Acta 1187:116–120, 1994; Zafra-Polo et al. Phytochemistry 42:253–271, 1996; Miyoshi et al. Biochim Biophys Acta 1365:443–452, 1998; Tormo et al. Arch Biochem Biophys 369:119–126, 1999; Motoyama et al. Bioorg Med Chem Lett 12:2089–2092, 2002). To explore a possible application of natural products from Annonaceous plants to cancer treatment, we have selected four bis-tetrahydrofuranic ACGs, three from Annona cherimolia (cherimolin-1, motrilin and laherradurin) and one from Rollinia mucosa (rollinianstatin-1) in order to fully describe their mechanisms responsible within the cell (Fig. 1). In this study, using a hepato-carcinoma cell line (HepG2) as a model, we showed that the bis-THF ACGs caused cell death through the induction of the apoptotic mitochondrial pathway. Their potency and behavior were compared with the classical mitochondrial respiratory chain Complex I inhibitor rotenone in every apoptotic pathway step.
Fig. 1
ACGs structures  相似文献   

14.
An assemblage of gastropods from the Thanetian of the Kolosh Formation from the Zakho region in northern Iraq is documented for the first time. The ten species represent the families Campanilidae Douvillé 1904, Potamididae H. & A. Adams 1854, Batillariidae Thiele 1929, Thiaridae Gill 1871, Pachychilidae Fischer & Crosse 1892, Cerithiidae Fleming 1822 and Pseudolividae de Gregorio 1880, suggesting a littoral to shallow sublittoral depositional environment. Six of the species are new and five are formally described as new species. At least seven species are also known from the Thanetian and/or Early Ypresian of the Ankara region in Turkey. Only a single species occurs also in the Paleocene of the Paris Basin. No relation to Paleocene and Eocene faunas of Pakistan and India is detectable. This points to a considerably bioprovincialism along the northern coast of the Tethys. Consequently we suppose the existence of an Anatolian Province in the Thanetian/Ypresian Mediterranean Region of the Tethys Realm, represented by rather homogeneous mollusc faunas from western Turkey and northern Iraq. Campanile zakhoense nov. sp., Pyrazopsis hexagonpyramidalis nov. sp., Pachymelania islamogluae nov. sp., “Faunus” dominicii nov. sp. and Pseudoaluco mesopotamicus nov. sp. are introduced as new species. Varicipotamides Pacaud & Harzhauser nov. nom. is proposed as the replacement name for Exechestoma Cossmann (1889) non Brandt (1837).  相似文献   

15.
This year is a special year for plant biotechnology. It was 30 years ago, on January 18 1983, one of the most important dates in the history of plant biotechnology, that three independent groups described Agrobacterium tumefaciens—mediated genetic transformation at the Miami Winter Symposium, leading to the production of normal, fertile transgenic plants (Bevan et al. in Nature 304:184–187, 1983; Fraley et al. in Proc Natl Acad Sci USA 80:4803–4807, 1983; Herrera-Estrella et al. in EMBO J 2:987–995, 1983; Vasil in Plant Cell Rep 27:1432–1440, 2008). Since then, plant biotechnology has rapidly advanced into a useful and valuable tool and has made a significant impact on crop production, development of a biotech industry and the bio-based economy worldwide.  相似文献   

16.
Multiple sclerosis (MS) is characterized as an autoimmune demyelinating disease. Numerous family studies have confirmed a strong genetic component underlying its etiology. After several decades of frustrating research, the advent and application of affordable genotyping of dense SNP maps in large data sets has ushered in a new era in which rapid progress is being made in our understanding of the genetics underlying many complex traits. For MS, one of the first discoveries to emerge in this new era was the association with rs6897932[T244I] in the interleukin-7 receptor alpha chain (IL7RA) gene (Gregory et al. in Nat Genet 39(9):1083–1091, 2007; International Multiple Sclerosis Genetics Consortium in N Engl J Med 357(9):851–862, 2007; Lundmark in Nat Genet 39(9):1108–1113, 2007), a discovery that was accompanied by functional data that suggest this variant is likely to be causative rather than a surrogate proxy (Gregory et al. in Nat Genet 39(9):1083–1091, 2007). We hypothesized that variations in other genes functionally related to IL7RA might also influence MS. We investigated this hypothesis by examining genes in the extended biological pathway related to IL7RA to identify novel associations. We identified 73 genes with putative functional relationships to IL7RA and subsequently genotyped 7,865 SNPs in and around these genes using an Illumina Infinium BeadChip assay. Using 2,961 case–control data sets, two of the gene regions examined, IL7 and SOCS1, had significantly associated single-nucleotide polymorphisms (SNPs) that further replicated in an independent case–control data set (4,831 samples) with joint p values as high as 8.29 × 10?6 and 3.48 × 10?7, respectively, exceeding the threshold for experiment-wise significance. Our results also implicate two additional novel gene regions that are likely to be associated with MS: PRKCE with p values reaching 3.47 × 10?4, and BCL2 with p values reaching 4.32 × 10?4. The TYK2 gene, which also emerged in our analysis, has recently been associated with MS (Ban et al. 2009). These results help to further delineate the genetic architecture of MS and validate our pathway approach as an effective method to identify novel associations in a complex disease.  相似文献   

17.
Two species of the genus Camponotites (Formicidae, Formicinae) are described from the Late Pliocene deposits of Willershausen, Lower Saxony, northern Germany: C. silvestris Steinbach, 1967, and C. steinbachi n. sp. The generic name Camponotites has been established for fossil (Tertiary) ants independently by Steinbach (Bericht der Naturhistorischen Gesellschaft zu Hannover 111:95–102, 1967) and by Dlussky (Trudy paleontologi?eskogo instituta, akademiâ nauk SSSR, 1981), each for materials of different stratigraphical and geographical origin. Though poorly described, Camponotites Steinbach, 1967, and the single included (type) species C. silvestris Steinbach, 1967 (a monotypic species from the Late Pliocene of Willershausen), were based upon indication in the sense of the ICZN. Therefore, both the generic and specific names are valid and available. Camponotites Dlussky, 1981 (and its type species C. macropterus Dlussky, 1981) were certainly introduced correctly and are therefore available, too; but due to its homonymy the generic name is not valid. The revision shows that in this rare case both generic names are not only homonyms but also synonyms.  相似文献   

18.
A new generic name, Stukalinia nom. nov., is proposed for a fossil Ordoviacian crinoid that currently has the preoccupied fossil generic name Lobocrinus Stukalina 1982 non Wachsmuth and Springer (1897), along with a new family name, Stukaliniidae nom. nov., instead of the illegitimate family name Lobocrinidae Stukalina (1982).  相似文献   

19.
Gereon Müller 《Morphology》2013,23(2):245-268
This paper addresses the question of how certain kinds of overlapping syncretisms in inflectional paradigms can be accounted for that Baerman et al. (Language 80:807–824, 2005) refer to as convergent/divergent bidirectional syncretisms (based on earlier work by Stump, Inflectional morphology, 2001). Bidirectional syncretism strongly resists accounts in terms of standard rules of exponence (or similar devices) that correlate inflection markers with (often underspecified) morpho-syntactic specifications (such rules are used in many morphological theories; e.g., Anderson, A-morphous morphology, 1992; Halle and Marantz in The view from building, pp. 111–176, 1993; Aronoff, Morphology by itself, 1994; Wunderlich in Yearbook of morphology 1995, pp. 93–114, 1996; and Stump, Inflectional morphology, 2001). The reason is that it is difficult to capture overlapping distributions by natural classes. In view of this, rules of referral have been proposed to derive bidirectional syncretism (Stump, Inflectional morphology, 2001; Baerman et al. (Language 80:807–824, 2005)). In contrast, I would like to pursue the hypothesis that systematic instances of overlapping syncretism ultimately motivate a new approach to inflectional morphology—one that fully dispenses with the assumption that morphological exponents are paired with morpho-syntactic feature specifications (and that therefore qualifies as radically non-morphemic): First, rules of exponence are replaced with feature co-occurrence restrictions (FCRs; Gazdar et al., Generalized Phrase Structure Grammar, 1985). For phonologically determined natural classes of exponents, FCRs state incompatibilites with morpho-syntactic feature specifications. Second, marker competition is resolved by a principle of Phonology-driven Marker Selection (PMS). PMS takes over the role of the Specificity (Blocking, Elsewhere, Panini) Principle of standard analyses. Empirically, the main focus is on Bonan declension; the analysis is subsequently extended to Gujarati conjugation and Latin o-declension, with further remarks on bidirectional syncretism in other inflectional paradigms.  相似文献   

20.
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