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91.
Background
Extensive focus is placed on the comparative analyses of consensus genotypes in the study of West Nile virus (WNV) emergence. Few studies account for genetic change in the underlying WNV quasispecies population variants. These variants are not discernable in the consensus genome at the time of emergence, and the maintenance of mutation-selection equilibria of population variants is greatly underestimated. The emergence of lineage 1 WNV strains has been studied extensively, but recent epidemics caused by lineage 2 WNV strains in Hungary, Austria, Greece and Italy emphasizes the increasing importance of this lineage to public health. In this study we explored the quasispecies dynamics of minority variants that contribute to cell-tropism and host determination, i.e. the ability to infect different cell types or cells from different species from Next Generation Sequencing (NGS) data of a historic lineage 2 WNV strain.Results
Minority variants contributing to host cell membrane association persist in the viral population without contributing to the genetic change in the consensus genome. Minority variants are shown to maintain a stable mutation-selection equilibrium under positive selection, particularly in the capsid gene region.Conclusions
This study is the first to infer positive selection and the persistence of WNV haplotype variants that contribute to viral fitness without accompanying genetic change in the consensus genotype, documented solely from NGS sequence data. The approach used in this study streamlines the experimental design seeking viral minority variants accurately from NGS data whilst minimizing the influence of associated sequence error. 相似文献92.
Alexandra Philipsen Erika Graf Thomas Jans Swantje Matthies Patricia Borel Michael Colla Laura Gentschow Daina Langner Christian Jacob Silke Groß-Lesch Esther Sobanski Barbara Alm Martina Schumacher-Stien Michael Roesler Wolfgang Retz Petra Retz-Junginger Bernhard Kis Mona Abdel-Hamid Viola Heinrich Michael Huss Catherine Kornmann Arne Bürger Ludger Tebartz van Elst Mathias Berger 《Attention deficit and hyperactivity disorders》2014,6(1):35-47
93.
Gilberto Parolo Thomas Abeli Graziano Rossi Giuseppina Dowgiallo Diethart Matthies 《Perspectives in Plant Ecology, Evolution and Systematics》2011,13(4):319
Leucojum aestivum L. (Amaryllidaceae) is a polycarpic C-S-European/W-Asiatic geophyte. It is a threatened wetland species and is protected in several European countries, as a consequence of the destruction or alteration of its habitats across Europe and the harvesting of its bulbs for medical purposes (alkaloids). This paper deals with the taxonomic status, morphology, distribution, ecology and population biology of this species, with special emphasis on habitat requirements, reproductive biology, and seed germination. A detailed study in N-Italy found that L. aestivum grows on alluvial soils with high nitrogen levels. The mean size of the plants increased with the water content of the soil. Similarly, within the habitats, the water and nitrogen contents of the soil were higher in plots with L. aestivum than in those without the species. Seed set of the plants was not influenced by the size of a population, but strongly increased with the density of flowering plants. This was due to a decrease in the proportion of unfertilised eggs, indicating pollen limitation of reproduction in low-density populations. Germination tests revealed that the optimal germination temperature is between 20 °C and 25 °C. 相似文献
94.
Larson CR Seng CO Lauman L Matthies HJ Wen J Blankenship RE Allen JP 《Photosynthesis research》2011,107(2):139-150
The Fenna–Matthews–Olson (FMO) antenna protein from the green bacterium Pelodictyon phaeum mediates the transfer of energy from the peripheral chlorosome antenna complex to the membrane-bound reaction center. The three-dimensional structure of this protein has been solved using protein crystallography to a resolution limit of 2.0 Å, with R work and R free values of 16.6 and 19.9%, respectively. The structure is a trimer of three identical subunits related by a threefold symmetry axis. Each subunit has two beta sheets that surround 8 bacteriochlorophylls. The bacteriochlorophylls are all five-coordinated, with the axial ligand being a histidine, serine, backbone carbonyl, or bound water molecule. The arrangement of the bacteriochlorophylls is generally well conserved in comparison to other FMO structures, but differences are apparent in the interactions with the surrounding protein. In this structure the position and orientation of the eighth bacteriochlorophyll is well defined and shows differences in its location and the coordination of the central Mg compared to previous models. The implications of this structure on the ability of the FMO protein to perform energy transfer are discussed in terms of the experimental optical measurements. 相似文献
95.
A Closer Look at Amphetamine-Induced Reverse Transport and Trafficking of the Dopamine and Norepinephrine Transporters 总被引:1,自引:0,他引:1
Amphetamine (AMPH) and its derivatives are regularly used in the treatment of a wide array of disorders such as attention-deficit
hyperactivity disorder (ADHD), obesity, traumatic brain injury, and narcolepsy (Prog Neurobiol 75:406–433, 2005; J Am Med Assoc 105:2051–2054, 1935; J Am Acad Child Adolesc Psychiatry 41:514–521, 2002; Neuron 43:261–269, 2004; Annu Rev Pharmacol Toxicol 47:681–698, 2007; Drugs Aging 21:67–79, 2004). Despite the important medicinal role for AMPH, it is more widely known for its psychostimulant and addictive properties
as a drug of abuse. The primary molecular targets of AMPH are both the vesicular monoamine transporters (VMATs) and plasma
membrane monoamine—dopamine (DA), norepinephrine (NE), and serotonin (5-HT)—transporters. The rewarding and addicting properties
of AMPH rely on its ability to act as a substrate for these transporters and ultimately increase extracellular levels of monoamines.
AMPH achieves this elevation in extracellular levels of neurotransmitter by inducing synaptic vesicle depletion, which increases
intracellular monoamine levels, and also by promoting reverse transport (efflux) through plasma membrane monoamine transporters
(J Biol Chem 237:2311–2317, 1962; Med Exp Int J Exp Med 6:47–53, 1962; Neuron 19:1271–1283, 1997; J Physiol 144:314–336, 1958; J Neurosci 18:1979–1986, 1998; Science 237:1219–1223, 1987; J Neurosc 15:4102–4108, 1995). This review will focus on two important aspects of AMPH-induced regulation of the plasma membrane monoamine transporters—transporter
mediated monoamine efflux and transporter trafficking. 相似文献
96.
97.
Population size and the risk of local extinction: empirical evidence from rare plants 总被引:13,自引:0,他引:13
Due to habitat fragmentation many plant species today occur mainly in small and isolated populations. Modeling studies predict that small populations will be threatened more strongly by stochastic processes than large populations, but there is little empirical evidence to support this prediction for plants. We studied the relationship between size of local populations (number of flowering plants) and survival over ten years for 359 populations of eight short-lived, threatened plants in northern Germany ( Lepidium campestre , Thlaspi perfoliatum , Rhinanthus minor , R . serotinus , Melampyrum arvense , M . nemorosum , Gentianella ciliata and G . germanica ). Overall, 27% of the populations became extinct during the study period. Probability of survival of a local population increased significantly with its size in all but one species ( R. minor ). However, estimated population sizes required for 90% probability of survival over 10 years varied widely among species. Survival probability increased with decreasing distance to the nearest conspecific population in R . serotinus , but not in the other species. The mean annual growth rate of surviving populations differed greatly between species, but was only for G . germanica significantly lower than 1, suggesting that there was no general deterministic decline in the number of plants due to deteriorating habitat conditions. We conclude that the extinction of populations was at least partly due to stochastic processes. This is supported by the fact that in all species a considerable proportion of small populations survived and developed into large populations. 相似文献
98.
Drosophila fragile X-related gene regulates the MAP1B homolog Futsch to control synaptic structure and function. 总被引:16,自引:0,他引:16
Y Q Zhang A M Bailey H J Matthies R B Renden M A Smith S D Speese G M Rubin K Broadie 《Cell》2001,107(5):591-603
Fragile X mental retardation gene (FMR1) encodes an RNA binding protein that acts as a negative translational regulator. We have developed a Drosophila fragile X syndrome model using loss-of-function mutants and overexpression of the FMR1 homolog (dfxr). dfxr nulls display enlarged synaptic terminals, whereas neuronal overexpression results in fewer and larger synaptic boutons. Synaptic structural defects are accompanied by altered neurotransmission, with synapse type-specific regulation in central and peripheral synapses. These phenotypes mimic those observed in mutants of microtubule-associated Futsch. Immunoprecipitation of dFXR shows association with futsch mRNA, and Western analyses demonstrate that dFXR inversely regulates Futsch expression. dfxr futsch double mutants restore normal synaptic structure and function. We propose that dFXR acts as a translational repressor of Futsch to regulate microtubule-dependent synaptic growth and function. 相似文献
99.
Rosemary J Redfield Wendy A Findlay Janine Bossé J Simon Kroll Andrew DS Cameron John HE Nash 《BMC evolutionary biology》2006,6(1):82-15
Background
Many bacteria can take up DNA, but the evolutionary history and function of natural competence and transformation remain obscure. The sporadic distribution of competence suggests it is frequently lost and/or gained, but this has not been examined in an explicitly phylogenetic context. Additional insight may come from the sequence specificity of uptake by species such as Haemophilus influenzae, where a 9 bp uptake signal sequence (USS) repeat is both highly overrepresented in the genome and needed for efficient DNA uptake. We used the distribution of competence genes and DNA uptake specificity in H. influenzae 's family, the Pasteurellaceae, to examine the ancestry of competence. 相似文献100.