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排序方式: 共有641条查询结果,搜索用时 15 毫秒
101.
102.
Rosa van den Berg Sander Kooijman Raymond Noordam Ashna Ramkisoensing Gustavo Abreu-Vieira Lauren L. Tambyrajah Wieneke Dijk Philip Ruppert Isabel M. Mol Barbara Kramar Rosanna Caputo Laura Sardón Puig Evelien M. de Ruiter Jan Kroon Menno Hoekstra Ronald J. van der Sluis Onno C. Meijer Ko Willems van Dijk Patrick C.N. Rensen 《Cell reports》2018,22(13):3521-3533
103.
104.
M. van der Gaag A. J. M. Debets H. D. Osiewacz R. F. Hoekstra 《Molecular & general genetics : MGG》1998,258(5):521-529
A natural population of recently isolated Podospora anserina strains was screened for homologues of the linear longevity-inducing plasmid pAL2-1. Of the 78 wild-type isolates, 14 hybridised
with a pAL2-1 specific probe, half of which contained a single plasmid and the other half multiple plasmid copies (plasmid
family). All strains except one plasmid-containing strain, senesced normally. However, no inserted plasmid sequences were
detected in the mitochondrial DNA, as was the case for the longevity-inducing pAL2-1 plasmid. Occasional loss of plasmids
and of repeated plasmid sequences occurred during sexual transfer. Plasmid transmission was equally efficient for mono- and
dikaryotic spores and was independent of the genetic background of the strains. Furthermore, horizontal transfer experiments
showed that the linear plasmid could easily infect plasmid-free strains. Horizontal transfer was even observed between strains
showing a clear vegetative incompatibility response (barrage). The linear plasmids are inherited maternally; however, paternal
transmission was observed in crosses between confronted vegetative-incompatible strains. Paternal transmission of the plasmid
was never observed using isolated spermatia for fertilisation, showing that mitochondrial plasmids can only gain access to
maternal sexual reproductive structures following horizontal transfer. These findings have implications for both the function
of vegetative incompatibility in fungi and for the mechanism of maintenance of linear plasmids.
Received: 13 November 1997 / Accepted: 17 February 1998 相似文献
105.
Storage behavior of Typha latifolia pollen at low water contents: Interpretation on the basis of water activity and glass concepts 总被引:5,自引:0,他引:5
Julia Buitink Christina Walters Folkert A. Hoekstra Jennifer Crane 《Physiologia plantarum》1998,103(2):145-153
Germplasm must be stored under optimal conditions to maximize longevity and efficiently maintain genetic resources. In order to identify optimal storage conditions, we investigated the effects of temperature (−5 to 45°C) and water content (<0.17 g H2 O g−1 dry weight) on longevity of Typha latifolia L. pollen. Longevity was highest at water contents corresponding to storage relative humidity (RH) of 11‐15% which corresponded to the shoulder of water sorption isotherms. Also coinciding with this shoulder were abrupt changes in heat capacity of water present in the pollen. Consistent with changes in isotherms with temperature and the concept of critical RH for storage, optimum water contents increased with decreasing temperature. An attempt was made to explain the aging behavior according to the glass concept. The water content‐temperature combinations of optimal storage were found to be below the glass transition curve, indicating that optimum storage conditions are achieved when intracellular glasses are present. We also found a change in activation energy of aging in Arrhenius plots around Tg , demonstrating a change in aging kinetics when the glassy state is lost. We concluL that Tg curves cannot be used solely to predict precise conditions of optimum storage, but might be useful for predictions of storage longevity above optimum water contents. The data imply that too much drying reduces longevity and should be avoided, particularly when cryogenic storage is considered. 相似文献
106.
The ultimate and proximate mechanisms driving the evolution of long tails in forest deer mice
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Evan P. Kingsley Krzysztof M. Kozak Susanne P. Pfeifer Dou‐Shuan Yang Hopi E. Hoekstra 《Evolution; international journal of organic evolution》2017,71(2):261-273
Understanding both the role of selection in driving phenotypic change and its underlying genetic basis remain major challenges in evolutionary biology. Here, we use modern tools to revisit a classic system of local adaptation in the North American deer mouse, Peromyscus maniculatus, which occupies two main habitat types: prairie and forest. Using historical collections, we find that forest‐dwelling mice have longer tails than those from nonforested habitat, even when we account for individual and population relatedness. Using genome‐wide SNP data, we show that mice from forested habitats in the eastern and western parts of their range form separate clades, suggesting that increased tail length evolved independently. We find that forest mice in the east and west have both more and longer caudal vertebrae, but not trunk vertebrae, than nearby prairie forms. By intercrossing prairie and forest mice, we show that the number and length of caudal vertebrae are not correlated in this recombinant population, indicating that variation in these traits is controlled by separate genetic loci. Together, these results demonstrate convergent evolution of the long‐tailed forest phenotype through two distinct genetic mechanisms, affecting number and length of vertebrae, and suggest that these morphological changes—either independently or together—are adaptive. 相似文献
107.
The genetic basis of phenotypic convergence in beach mice: similar pigment patterns but different genes 总被引:2,自引:0,他引:2
Steiner CC Römpler H Boettger LM Schöneberg T Hoekstra HE 《Molecular biology and evolution》2009,26(1):35-45
Convergent evolution is a widespread phenomenon seen in diverseorganisms inhabiting similar selective environments. However,it is unclear if similar phenotypes are produced by the sameor different genes and mutations. Here we analyze the molecularmechanisms underlying convergent pigment pattern among subspeciesof the beach mouse (Peromyscus polionotus) inhabiting the Gulfand Atlantic coasts of Florida. In these two geographic regions,separated by more than 300 km, "beach mice" have lighter coloredcoats than do their mainland counterparts, produced by naturalselection for camouflage against the pale coastal sand dunes.We measured color pattern in eight beach mouse subspecies andshowed that three of the Gulf Coast subspecies are more phenotypicallysimilar to an Atlantic coast subspecies than to their Gulf Coastneighbors. However, light-colored beach mice do not form a monophyleticgroup. Previous results implicated a single derived amino acidchange in the melanocortin-1 receptor (Mc1r) as a major contributorto pigment pattern in the Gulf Coast beach mice; despite phenotypicsimilarities, the derived Mc1r allele was not found in the Atlanticcoast beach mouse populations. Here we show that Atlantic coastbeach mice have high levels of Mc1r polymorphism but they lackunique alleles. Functional assays revealed that single aminoacid mutations segregating in Atlantic coast beach mice do notcause any change in Mc1r activity compared with the activityof Mc1r from dark-colored mice. These joint results show thatconvergent pigment patterns in recently diverged beach mousesubspecies—whose developmental constraints are presumablysimilar—have evolved through a diversity of genetic mechanisms. 相似文献
108.
109.
Willeke de Haan Jitske de Vries-van der Weij Isabel M. Mol Menno Hoekstra Johannes A. Romijn J. Wouter Jukema Louis M. Havekes Hans M.G. Princen Patrick C.N. Rensen 《Biochimica et Biophysica Acta (BBA)/Molecular and Cell Biology of Lipids》2009,1791(3):191-197
Pregnane X receptor (PXR) agonism has been shown to affect multiple steps in both the synthesis and catabolism of HDL, but its integrated effect on HDL metabolism in vivo remains unclear. The aim of this study was to evaluate the net effect of PXR agonism on HDL metabolism in ApoE?3-Leiden (E3L) and E3L.CETP mice, well-established models for human-like lipoprotein metabolism. Female mice were fed a diet with increasing amounts of the potent PXR agonist 5-pregnen-3β-ol-20-one-16α-carbonitrile (PCN). In E3L and E3L.CETP mice, PCN increased liver lipids as well as plasma cholesterol and triglycerides. However, whereas PCN increased cholesterol contained in large HDL-1 particles in E3L mice, it dose-dependently decreased HDL-cholesterol in E3L.CETP mice, indicating that CETP expression dominates the effect of PCN on HDL metabolism. Analysis of the hepatic expression of genes involved in HDL metabolism showed that PCN decreased expression of genes involved in HDL synthesis (Abca1, Apoa1), maturation (Lcat, Pltp) and clearance (Sr-b1). The HDL-increasing effect of PCN, observed in E3L mice, is likely caused by a marked decrease in hepatic SR-BI protein expression, and completely reversed by CETP expression. We conclude that chronic PXR agonism dose-dependently reduces plasma HDL-cholesterol in the presence of CETP. 相似文献
110.
Establishment of plasma membrane polarity involves numerous intracellular sorting events. In the past few years, it has become apparent that there is a subapical, non-Golgi compartment located in the hub of the sorting pathways involved. This 'subapical compartment', which probably consists of a heterogeneous subset of functionally distinct domains related to endosomes, contains some well-characterized components involved in polarity-dependent sorting and targeting of proteins and lipids. This article discusses the evidence supporting the existence of such a compartment, its biogenesis and its role in cell polarity. 相似文献