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61.
Evolution of fitnesses and allele frequencies in a population with spatially heterogeneous selection pressures 总被引:2,自引:0,他引:2 下载免费PDF全文
The level of gene flow considerably influences the outcome of evolutionary processes in structured populations with spatial heterogeneity in selection pressures; low levels of gene flow may allow local adaptation whereas high levels of gene flow may oppose this process thus preventing the stable maintenance of polymorphism. Indeed, proportions of fitness space that successfully maintain polymorphism are substantially larger in spatially heterogenous populations with lower to moderate levels of gene flow when compared to single-deme models. Nevertheless, the effect of spatial heterogeneity on the evolutionary construction of polymorphism is less clear. We have investigated the levels of polymorphism resulting from a simple two-deme construction model, which incorporates recurrent mutation as well as selection. We further compared fitness properties, stability of equilibria, and frequency distribution patterns emerging from the construction approach and compared these to the static fitness-space approach. The construction model either promotes or constrains the level of polymorphisms, depending on the levels of gene flow. Comparison of the fitness properties resulting from both approaches shows that they maintain variation in different parts of fitness space. The part of fitness space resulting from construction is more stable than that implied by the ahistoric fitness-space approach. Finally, the equilibrium allele-frequency distribution patterns vary substantially with different levels of gene flow, underlining the importance of correctly sampling spatial structure if these patterns are to be used to estimate population-genetic processes. 相似文献
62.
Bruce Schoelitsz Bastiaan G. Meerburg Willem Takken 《Entomologia Experimentalis et Applicata》2019,167(1):14-26
Households are mini‐ecosystems that provide a variety of conditions in which a variety of insect species can develop. Whether these insects are considered pests, largely depends on the perception, attitudes, and knowledge of the human inhabitants of the house. If considered unacceptable, residents can attempt to manage the insects themselves, or hire a professional. A pest management professional can provide a quick‐fix solution, often relying on the sole use of insecticides, or a sustainable solution through integrated pest management (IPM). In this review, it is discussed how the public's perception, attitudes, and knowledge affect the implementation of IPM in the household through the following steps: inspection, identification, establishment of a threshold level, pest control, and evaluation of effectiveness. Furthermore, recent and novel developments within the fields of inspection, identification, and pest control that allow to address pest infestations more effectively are described and their implementation in the household environment is discussed. In general, pest management in the household environment is reactive instead of pro‐active. The general public lacks the knowledge of the pest insects’ biology to identify the species, perform a proper inspection and identify causes of pest presence, as well as the knowledge of the available tools for monitoring and pest control. The percentage of individuals that seek professional aid in identification and pest control is relatively low. Moreover, the perception of and attitudes towards household insects generally result in low threshold levels. Current developments of methods for monitoring, identification, and control of insect pests in the household environment are promising, such as DNA barcoding, matrix‐assisted laser desorption/ionization time‐of‐flight and RNA interference. Efforts should be strengthened to alter the perception and attitude, and increase the knowledge of the non‐professional stakeholders, so that correct pest management decisions can be taken. 相似文献
63.
64.
Marie M. Lockhart Bastiaan J.D. Boukens Aimee L. Phelps Christina-Lin M. Brown Katelynn A. Toomer Tara A. Burns Rupak D. Mukherjee Russell A. Norris Thomas C. Trusk Maurice J.B. van den Hoff Andy Wessels 《Developmental biology》2014
Recent studies using mouse models for cell fate tracing of epicardial derived cells (EPDCs) have demonstrated that at the atrioventricular (AV) junction EPDCs contribute to the mesenchyme of the AV sulcus, the annulus fibrosus, and the parietal leaflets of the AV valves. There is little insight, however, into the mechanisms that govern the contribution of EPDCs to these tissues. While it has been demonstrated that bone morphogenetic protein (Bmp) signaling is required for AV cushion formation, its role in regulating EPDC contribution to the AV junction remains unexplored. To determine the role of Bmp signaling in the contribution of EPDCs to the AV junction, the Bmp receptor activin-like kinase 3 (Alk3; or Bmpr1a) was conditionally deleted in the epicardium and EPDCs using the mWt1/IRES/GFP-Cre (Wt1Cre) mouse. Embryonic Wt1Cre;Alk3fl/fl specimens showed a significantly smaller AV sulcus and a severely underdeveloped annulus fibrosus. Electrophysiological analysis of adult Wt1Cre;Alk3fl/fl mice showed, unexpectedly, no ventricular pre-excitation. Cell fate tracing revealed a significant decrease in the number of EPDCs within the parietal leaflets of the AV valves. Postnatal Wt1Cre;Alk3fl/fl specimens showed myxomatous changes in the leaflets of the mitral valve. Together these observations indicate that Alk3 mediated Bmp signaling is important in the cascade of events that regulate the contribution of EPDCs to the AV sulcus, annulus fibrosus, and the parietal leaflets of the AV valves. Furthermore, this study shows that EPDCs do not only play a critical role in early developmental events at the AV junction, but that they also are important in the normal maturation of the AV valves. 相似文献
65.
M Chaki R Airik AK Ghosh RH Giles R Chen GG Slaats H Wang TW Hurd W Zhou A Cluckey HY Gee G Ramaswami CJ Hong BA Hamilton I Cervenka RS Ganji V Bryja HH Arts J van Reeuwijk MM Oud SJ Letteboer R Roepman H Husson O Ibraghimov-Beskrovnaya T Yasunaga G Walz L Eley JA Sayer B Schermer MC Liebau T Benzing S Le Corre I Drummond S Janssen SJ Allen S Natarajan JF O'Toole M Attanasio S Saunier C Antignac RK Koenekoop H Ren I Lopez A Nayir C Stoetzel H Dollfus R Massoudi JG Gleeson SP Andreoli DG Doherty 《Cell》2012,150(3):533-548
Nephronophthisis-related ciliopathies (NPHP-RC) are degenerative recessive diseases that affect kidney, retina, and brain. Genetic defects in NPHP gene products that localize to cilia and centrosomes defined them as "ciliopathies." However, disease mechanisms remain poorly understood. Here, we identify by whole-exome resequencing, mutations of MRE11, ZNF423, and CEP164 as causing NPHP-RC. All three genes function within the DNA damage response (DDR) pathway. We demonstrate that, upon induced DNA damage, the NPHP-RC proteins ZNF423, CEP164, and NPHP10 colocalize to nuclear foci positive for TIP60, known to activate ATM at sites?of DNA damage. We show that knockdown of CEP164 or ZNF423 causes sensitivity to DNA damaging agents and that cep164 knockdown in zebrafish results in dysregulated DDR and an NPHP-RC phenotype. Our findings link degenerative diseases of the kidney and retina, disorders of increasing prevalence, to mechanisms of DDR. PAPERFLICK: 相似文献
66.
Microtubule biogenesis requires alphabeta tubulin dimers that are generated from alpha and beta tubulin following post-translational modification by several tubulin folding cofactors (TFCs). Here we report the isolation and characterization of Arabidopsis TFCB (AtTFCB). AtTFCB is expressed in all organs of Arabidopsis. The subcellular localization of AtTFCB is mainly cytosolic. AtTFCB-overexpressing cells have fewer microtubules compared with the controls. Multimode fluorescence resonance energy transfer (FRET) microscopy reveals a direct physical interaction of AtTFCB with alpha tubulin in living plant cells. We conclude that AtTFCB interacts with alpha tubulin in vivo and its overexpression reduces the number of microtubules. 相似文献
67.
Resurrecting complexity: the interplay of plasticity and rapid evolution in the multiple trait response to strong changes in predation pressure in the water flea Daphnia magna 下载免费PDF全文
Robby Stoks Lynn Govaert Kevin Pauwels Bastiaan Jansen Luc De Meester 《Ecology letters》2016,19(2):180-190
A resurrection ecology reconstruction of 14 morphological, life history and behavioural traits revealed that a natural Daphnia magna population rapidly tracked changes in fish predation by integrating phenotypic plasticity and widespread evolutionary changes both in mean trait values and in trait plasticity. Increased fish predation mainly generated rapid adaptive evolution of plasticity (especially in the presence of maladaptive ancestral plasticity) resulting in an important change in the magnitude and direction of the multivariate reaction norm. Subsequent relaxation of the fish predation pressure resulted in reversed phenotypic plasticity and mainly caused evolution of the trait means towards the ancestral pre‐fish means. Relaxation from fish predation did, however, not result in a complete reversal to the ancestral fishless multivariate phenotype. Our study emphasises that the study population rapidly tracked environmental changes through a mosaic of plasticity, evolution of trait means and evolution of plasticity to generate integrated phenotypic changes in multiple traits. 相似文献
68.
RNase MRP is a eukaryotic endoribonuclease involved in nucleolar and mitochondrial RNA processing events. RNase MRP is a ribonucleoprotein particle, which is structurally related to RNase P, an endoribonuclease involved in pre-tRNA processing. Most of the protein components of RNase MRP have been reported to be associated with RNase P as well. In this study we determined the association of these protein subunits with the human RNase MRP and RNase P particles by glycerol gradient sedimentation and coimmunoprecipitation. In agreement with previous studies, RNase MRP sedimented at 12S and 60-80S. In contrast, only a single major peak was observed for RNase P at 12S. The analysis of individual protein subunits revealed that hPop4 (also known as Rpp29), Rpp21, Rpp20, and Rpp25 only sedimented in 12S fractions, whereas hPop1, Rpp40, Rpp38, and Rpp30 were also found in 60-80S fractions. In agreement with their cosedimentation with RNase P RNA in the 12S peak, coimmunoprecipitation with VSV-epitope-tagged protein subunits revealed that hPop4, Rpp21, and in addition Rpp14 preferentially associate with RNase P. These data show that hPop4, Rpp21, and Rpp14 may not be associated with RNase MRP. Furthermore, Rpp20 and Rpp25 appear to be associated with only a subset of RNase MRP particles, in contrast to hPop1, Rpp40, Rpp38, and Rpp30 (and possibly also hPop5), which are probably associated with all RNase MRP complexes. Our data are consistent with a transient association of Rpp20 and Rpp25 with RNase MRP, which may be inversely correlated to its involvement in pre-rRNA processing. 相似文献
69.
P S Oud D J Zahniser M C Raaijmakers P G Vooijs R T Van de Walle 《Analytical and quantitative cytology》1981,3(4):289-294
A staining method developed for use with BioPEPR (Biological Precision Encoding and Pattern Recognition), an automated image-analysis system for cervical smears, is described. The stain is a combination of the Feulgen procedure, with thionine-SO2 as the Schiff reagent, and Congo red, which is used as a counterstain. The stain resulted in smears suitable both for microscopic diagnosis and for BioPEPR measurements made on photonegatives at a single wavelength 545 nm. A high level of reproducibility and accuracy of nuclear and cytoplasmic area measurements was obtained. Nuclear integrated optical density could be well measured and was shown to be useful in discriminating between normal and abnormal cells. Using a combination of morphologic features, a high level of cell classification accuracy was reached. The possibility of using the stain for more detailed studies is discussed. 相似文献
70.
The active principle triggering the metabolic outburst of theappendices of certain arum lily species has been purified andpartially characterized. Although in the past it has been thoughtof as a single factor ("calorigen"), both paper chromatographyand DEAE-Sephadex ion exchange chromatography reveal that thereare two compounds (calorigen I and II) with calorigen activity.These can act alone or together, but show no synergism. Theyare low-molecular compounds which appear to be common constituentsof the inflorescence of Sauromatum guttatum Schott. CalorigenII is also present in the spadix of Arum maculatum L., Arumdioscoridis Sibth. & Sm., and Dracunculus vulgaris Schott.Calorigen I absorbs UV at 242, 267 and 278 nm, calorigen IIat 229 and 295 nm. No spectral changes are noted in alkalineenvironment, whereas at low pH-values there is a shift of theabsorption peaks of both compounds towards longer wavelengths.Calorigen II displays a strong blue fluorescence and has a maximalemission at 410 nm when activated at 295 nm. The possible mechanismof calorigen action is discussed.
1 Present address: Department of Biochemistry, University ofWashington, Seattle, Washington 98195, U.S.A. (Received August 26, 1974; ) 相似文献