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11.
Utility of the white gene in estimating phylogenetic relationships among mosquitoes (Diptera: Culicidae) 总被引:2,自引:0,他引:2
The utility of a nuclear protein-coding gene for reconstructing
phylogenetic relationships within the family Culicidae was explored.
Relationships among 13 species representing three subfamilies and nine
genera of Culicidae were analyzed using a 762-bp fragment of coding
sequence from the eye color gene, white. Outgroups for the study were two
species from the sister group Chaoboridae. Sequences were determined from
clone PCR products amplified from genomic DNA, and aligned following
conceptual intron splicing and amino acid translation. Third codon
positions were characterized by high levels of divergence and biased
nucleotide composition, the intensity and direction of which varied among
taxa. Equal weighting of all characters resulted in parsimony and
neighboring-joining trees at odds with the generally accepted phylogenetic
hypothesis based on morphology and rDNA sequences. The application of
differential weighting schemes recovered the traditional hypothesis, in
which the subfamily Anophelinae formed the basal clade. The subfamily
Toxorhynchitinae occupied an intermediate position, and was a sister group
to the subfamily Culicinae. Within Culicinae, the genera Sabethes and
Tripteroides formed an ancestral clade, while the Culex-Deinocerites and
Aedes- Haemagogus clades occupied increasingly derived positions in the
molecular phylogeny. An intron present in the Culicinae- Toxorhynchitinae
lineage and one outgroup taxon was absent in the basal Anophelinae lineage
and the second outgroup taxon, suggesting that intron insertions or
deletions may not always be reliable systematic characters.
相似文献
12.
Christiane Roscher Vicky M. Temperton Michael Scherer-Lorenzen Martin Schmitz Jens Schumacher Bernhard Schmid Nina Buchmann Wolfgang W. Weisser Ernst-Detlef Schulze 《Ecology letters》2005,8(4):419-429
In a large integrated biodiversity project (‘The Jena Experiment’ in Germany) we established two experiments, one with a pool of 60 plant species that ranged broadly from dominant to subordinate competitors on large 20 × 20 m and small 3.5 × 3.5 m plots (= main experiment), and one with a pool of nine potentially dominant species on small 3.5 × 3.5 m plots (= dominance experiment). We found identical positive species richness–aboveground productivity relationships in the main experiment at both scales. This result suggests that scaling up, at least over the short term, is appropriate in interpreting the implications of such experiments for larger‐scale patterns. The species richness–productivity relationship was more pronounced in the experiment with dominant species (46.7 and 82.6% yield increase compared to mean monoculture, respectively). Additionally, transgressive overyielding occurred more frequently in the dominance experiment (67.7% of cases) than in the main experiment (23.4% of cases). Additive partitioning and relative yield total analyses showed that both complementarity and selection effects contributed to the positive net biodiversity effect. 相似文献
13.
Background
Adverse drug reactions (ADRs) are now recognized as an important cause of hospital admissions, with a proportion ranging from 0.9–7.9%. They also constitute a significant economic burden. We thus aimed at determining the prevalence and the economic burden of ADRs presenting to Medical Emergency Department (ED) of a tertiary referral center in India 相似文献14.
Christopher NJ Young Anthony Sinadinos Alexis Lefebvre Philippe Chan Stephen Arkle David Vaudry Dariusz C Gorecki 《Autophagy》2015,11(1):113-130
P2RX7 is an ATP-gated ion channel, which can also exhibit an open state with a considerably wider permeation. However, the functional significance of the movement of molecules through the large pore (LP) and the intracellular signaling events involved are not known. Here, analyzing the consequences of P2RX7 activation in primary myoblasts and myotubes from the Dmdmdx mouse model of Duchenne muscular dystrophy, we found ATP-induced P2RX7-dependent autophagic flux, leading to CASP3-CASP7-independent cell death. P2RX7-evoked autophagy was triggered by LP formation but not Ca2+ influx or MAPK1-MAPK3 phosphorylation, 2 canonical P2RX7-evoked signals. Phosphoproteomics, protein expression inference and signaling pathway prediction analysis of P2RX7 signaling mediators pointed to HSPA2 and HSP90 proteins. Indeed, specific HSP90 inhibitors prevented LP formation, LC3-II accumulation, and cell death in myoblasts and myotubes but not in macrophages. Pharmacological blockade or genetic ablation of p2rx7 also proved protective against ATP-induced death of muscle cells, as did inhibition of autophagy with 3-MA. The functional significance of the P2RX7 LP is one of the great unknowns of purinergic signaling. Our data demonstrate a novel outcome—autophagy—and show that molecules entering through the LP can be targeted to phagophores. Moreover, we show that in muscles but not in macrophages, autophagy is needed for the formation of this LP. Given that P2RX7-dependent LP and HSP90 are critically interacting in the ATP-evoked autophagic death of dystrophic muscles, treatments targeting this axis could be of therapeutic benefit in this debilitating and incurable form of muscular dystrophy. 相似文献
15.
June E. Swinburne Helen Bogle Jolanta Klukowska-Rötzler Michaela Drögemüller Tosso Leeb Elizabeth Temperton Gaudenz Dolf Vincent Gerber 《Mammalian genome》2009,20(8):504-515
Recurrent airway obstruction (RAO), or heaves, is a naturally occurring asthma-like disease that is related to sensitisation
and exposure to mouldy hay and has a familial basis with a complex mode of inheritance. A genome-wide scanning approach using
two half-sibling families was taken in order to locate the chromosome regions that contribute to the inherited component of
this condition in these families. Initially, a panel of 250 microsatellite markers, which were chosen as a well-spaced, polymorphic
selection covering the 31 equine autosomes, was used to genotype the two half-sibling families, which comprised in total 239
Warmblood horses. Subsequently, supplementary markers were added for a total of 315 genotyped markers. Each half-sibling family
is focused around a severely RAO-affected stallion, and the phenotype of each individual was assessed for RAO and related
signs, namely, breathing effort at rest, breathing effort at work, coughing, and nasal discharge, using an owner-based questionnaire.
Analysis using a regression method for half-sibling family structures was performed using RAO and each of the composite clinical
signs separately; two chromosome regions (on ECA13 and ECA15) showed a genome-wide significant association with RAO at P < 0.05. An additional 11 chromosome regions showed a more modest association. This is the first publication that describes
the mapping of genetic loci involved in RAO. Several candidate genes are located in these regions, a number of which are interleukins.
These are important signalling molecules that are intricately involved in the control of the immune response and are therefore
good positional candidates. 相似文献
16.
In situ hybridization at the electron microscope level: hybrid detection by autoradiography and colloidal gold 总被引:14,自引:4,他引:10
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In situ hybridization has become a standard method for localizing DNA or RNA sequences in cytological preparations. We developed two methods to extend this technique to the transmission electron microscope level using mouse satellite DNA hybridization to whole mount metaphase chromosomes as the test system. The first method devised is a direct extension of standard light microscope level using mouse satellite DNA hybridization to whole mount metaphase chromosomes as the test system. The first method devised is a direct extension of standard light microscope in situ hybridization. Radioactively labeled complementary RNA (cRNA) is hybridized to metaphase chromosomes deposited on electron microscope grids and fixed in 70 percent ethanol vapor; hybridixation site are detected by autoradiography. Specific and intense labeling of chromosomal centromeric regions is observed even after relatively short exposure times. Inerphase nuclei present in some of the metaphase chromosome preparations also show defined paatterms of satellite DNA labeling which suggests that satellite-containing regions are associate with each other during interphase. The sensitivity of this method is estimated to at least as good as that at the light microscope level while the resolution is improved at least threefold. The second method, which circumvents the use of autoradiogrphic detection, uses biotin-labeled polynucleotide probes. After hybridization of these probes, either DNA or RNA, to fixed chromosomes on grids, hybrids are detected via reaction is improved at least threefold. The second method, which circumvents the use of autoradiographic detection, uses biotin-labeled polynucleotide probes. After hybridization of these probes, either DNA or RNA, to fixed chromosomes on grids, hybrids are detected via reaction with an antibody against biotin and secondary antibody adsorbed to the surface of over centromeric heterochromatin and along the associated peripheral fibers. Labeling is on average ten times that of background binding. This method is rapid and possesses the potential to allow precise ultrastructual localization of DNA sequences in chromosomes and chromatin. 相似文献
17.
Moyes DL Martin A Sawcer S Temperton N Worthington J Griffiths DJ Venables PJ 《Genomics》2005,86(3):337-341
The human endogenous retroviruses HERV-K113 and HERV-K115 are full-length proviruses but unusual in being found in only a proportion of the population. Here, we study the geographic distribution of these HERVs and their prevalence in autoimmune disease. The frequency of HERV-K113 and HERV-K115 in 174 individuals from Africa was 21.8 and 34.1%, respectively, compared to 4.16 and 1% in 96 people in the United Kingdom (p < 0.001). Prevalence in Yemen (n = 56) was 8 and 7.14% and in Papua New Guinea (n = 54) 0% for both. In the United Kingdom, HERV-K113 was found in 15.6% of 96 Sj?gren's syndrome patients (p < 0.01) and 11.9% of 109 multiple sclerosis patients (p < 0.05). No increase in prevalence in either disease was seen with HERV-K115. These data suggest that both viruses are recently integrated and/or under positive evolutionary selection pressure. HERV-K113 may be a genetic risk factor for some types of autoimmunity. 相似文献
18.
Whether a small cell, a small genome or a minimal set of chemical reactions with self-replicating properties, simplicity is beguiling. As Leonardo da Vinci reportedly said, ‘simplicity is the ultimate sophistication''. Two diverging views of simplicity have emerged in accounts of symbiotic and commensal bacteria and cosmopolitan free-living bacteria with small genomes. The small genomes of obligate insect endosymbionts have been attributed to genetic drift caused by small effective population sizes (Ne). In contrast, streamlining theory attributes small cells and genomes to selection for efficient use of nutrients in populations where Ne is large and nutrients limit growth. Regardless of the cause of genome reduction, lost coding potential eventually dictates loss of function. Consequences of reductive evolution in streamlined organisms include atypical patterns of prototrophy and the absence of common regulatory systems, which have been linked to difficulty in culturing these cells. Recent evidence from metagenomics suggests that streamlining is commonplace, may broadly explain the phenomenon of the uncultured microbial majority, and might also explain the highly interdependent (connected) behavior of many microbial ecosystems. Streamlining theory is belied by the observation that many successful bacteria are large cells with complex genomes. To fully appreciate streamlining, we must look to the life histories and adaptive strategies of cells, which impose minimum requirements for complexity that vary with niche. 相似文献
19.
Plant diversity surpasses plant functional groups and plant productivity as driver of soil biota in the long term 总被引:1,自引:0,他引:1
Eisenhauer N Milcu A Sabais AC Bessler H Brenner J Engels C Klarner B Maraun M Partsch S Roscher C Schonert F Temperton VM Thomisch K Weigelt A Weisser WW Scheu S 《PloS one》2011,6(1):e16055
Background
One of the most significant consequences of contemporary global change is the rapid decline of biodiversity in many ecosystems. Knowledge of the consequences of biodiversity loss in terrestrial ecosystems is largely restricted to single ecosystem functions. Impacts of key plant functional groups on soil biota are considered to be more important than those of plant diversity; however, current knowledge mainly relies on short-term experiments.Methodology/Principal Findings
We studied changes in the impacts of plant diversity and presence of key functional groups on soil biota by investigating the performance of soil microorganisms and soil fauna two, four and six years after the establishment of model grasslands. The results indicate that temporal changes of plant community effects depend on the trophic affiliation of soil animals: plant diversity effects on decomposers only occurred after six years, changed little in herbivores, but occurred in predators after two years. The results suggest that plant diversity, in terms of species and functional group richness, is the most important plant community property affecting soil biota, exceeding the relevance of plant above- and belowground productivity and the presence of key plant functional groups, i.e. grasses and legumes, with the relevance of the latter decreasing in time.Conclusions/Significance
Plant diversity effects on biota are not only due to the presence of key plant functional groups or plant productivity highlighting the importance of diverse and high-quality plant derived resources, and supporting the validity of the singular hypothesis for soil biota. Our results demonstrate that in the long term plant diversity essentially drives the performance of soil biota questioning the paradigm that belowground communities are not affected by plant diversity and reinforcing the importance of biodiversity for ecosystem functioning. 相似文献20.
Christina M. Schreiber Bo Zeng Vicky M. Temperton Uwe Rascher Marian Kazda Ulrich Schurr Agnes H?ltkemeier Arnd J. Kuhn 《Plant and Soil》2011,344(1-2):111-129
The effects of flooding on rhizospheric organic acid concentrations of three abundant flooding tolerant plant species (Alternanthera philoxeroides Mart., Arundinella anomala Steud., Salix variegata Franch.) from the water fluctuation zone of the Three Gorges Reservoir (TGR, Yangtze River) were investigated. Soil solution samples of eight low molecular weight organic acids were obtained from rhizotrons using micro suction cups during 3 weeks of waterlogging, after 6 weeks flooding and after a 1 week recovery. To estimate the contribution of water temperature and microbial community, plants in sterile glass bead substrate and original Yangtze sediment were submerged in laboratory at +10°, +20° and +30°C. Waterlogged plants did seldom express a significantly different pattern of rhizospheric organic acid (OA) composition compared to control plants. Flooding caused no burst of organic acid concentration in soil solution: All species express a silencing strategy. Average OA levels were higher in A. anomala rhizosphere than in the other two species, but increased again after resurfacing in all species. Temperature had a stronger influence in sediment than in sterile setup. In contrast to field measurements, succinate, malate and citrate were detected in the sterile setup. Microbial contribution appeared to have great influence on increasing OA occurrence. 相似文献