Angiosperm inflorescences develop in two fundamentally different ways. In monopodial plants, for example in Arabidopsis thaliana, the flowers are initiated as lateral appendages of a central ...indeterminate inflorescence meristem. In sympodial plants, flowers arise by terminal differentiation of the inflorescence meristem, while further inflorescence development proceeds from new sympodial meristems that are generated at the flank of the terminal flower. We have used the sympodial model species Petunia hybrida to investigate inflorescence development. Here, we describe a mutant, bonsai (bns), which is defective in flower formation, inflorescence branching, and control of meristem size. Detailed microscopic analysis revealed that bns meristems retain vegetative charateristics including spiral phyllotaxis. Consistent with a block in flower formation, bns mutants exhibit a deregulated expression of various MADS-box genes. Molecular analysis revealed that the bns mutant carries a transposon insertion in the previously described EVERGREEN (EVG) gene, which belongs to the WUSCHEL-LIKE HOMEOBOX (WOX) transcription factor gene family. EVG falls in the WOX9 subfamily, which has diverse developmental functions in angiosperms. The comparison of WOX9 orthologues in five model species for flowering shows that these genes play functionally divergent roles in monopodial and sympodial plants, indicating that the WOX9 regulatory node may have played an important role in the evolution of shoot architecture.
Reconstructing Oligocene–Miocene paleoelevation
contributes to our understanding of the evolutionary history of the European
Alps and sheds light on geodynamic and Earth surface processes involved in
...the development of Alpine topography. Despite being one of the most
intensively explored mountain ranges worldwide, constraints on the elevation
history of the European Alps remain scarce. Here we present stable and
clumped isotope measurements to provide a new paleoelevation estimate for
the mid-Miocene (∼14.5 Ma) European Central Alps. We apply
stable isotope δ–δ paleoaltimetry to near-sea-level
pedogenic carbonate oxygen isotope (δ18O) records from the
Northern Alpine Foreland Basin (Swiss Molasse Basin) and high-Alpine
phyllosilicate hydrogen isotope (δD) records from the Simplon Fault
Zone (Swiss Alps). We further explore Miocene paleoclimate and
paleoenvironmental conditions in the Swiss Molasse Basin through carbonate
stable (δ18O, δ13C) and clumped (Δ47)
isotope data from three foreland basin sections in different alluvial
megafan settings (proximal, mid-fan, and distal). Combined pedogenic
carbonate δ18O values and Δ47 temperatures
(30±5 ∘C) yield a near-sea-level precipitation
δ18Ow value of -5.8±1.2 ‰ and, in
conjunction with the high-Alpine phyllosilicate δD value of -14.6±0.3 ‰, suggest that the region surrounding the
Simplon Fault Zone attained surface elevations of >4000 m no
later than the mid-Miocene. Our near-sea-level δ18Ow
estimate is supported by paleoclimate (iGCM ECHAM5-wiso) modeled δ18O values, which vary between −4.2 ‰ and −7.6 ‰ for
the Northern Alpine Foreland Basin.
This paper presents the model for simulation of vibration and dynamic loads in external gear pumps. The calculation has been carried out in Matlab/Simulink program. The vibrations of gears are ...excited due to the variable pressure forces and variable stiffness of the gearing. In this model the stiffness and damping coefficient of sliding bearings as well as the bending stiffness of gear wheels have been included. The influence of pressure and rotational speed on the dynamic forces in the bearings have been analyzed.
This paper reports the synthesis of compounds formed by two indole systems separated by a heterocycle (pyridine or piperazine). As a primary screening, the new compounds were submitted to the ...National Cancer Institute for evaluation of antitumor activity in the human cell line screen. The pyridine derivatives were far more active than the piperazine derivatives. For the study of the mechanism of action, the most active compounds were subjected to COMPARE analysis and to further biological tests including proteasome inhibition and inhibition of plasma membrane electron transport. The compound bearing the 5-methoxy-2-indolinone moiety was subjected to the first in vivo experiment (hollow fiber assay) and was active. It was therefore selected for the second in vivo experiment (human tumor xenograft in mice). In conclusion we demonstrated that this approach was successful, since some of the compounds described are much more active than the numerous, so far prepared and tested 3-indolylmethylene-2-indolinones.
To understand which reproductive barriers initiate speciation is a major question in evolutionary research. Despite their high species numbers and specific biology, there are only few studies on ...speciation in Hymenoptera. This study aims to identify very early reproductive barriers in a local, sympatric population of Nasonia vitripennis (Walker 1836), a hymenopterous parasitoid of fly pupae. We studied ecological barriers, sexual barriers, and the reduction in F1-female offspring as a postmating barrier, as well as the population structure using microsatellites.
We found considerable inbreeding within female strains and a population structure with either three or five subpopulation clusters defined by microsatellites. In addition, there are two ecotypes, one parasitizing fly pupae in bird nests and the other on carrion. The nest ecotype is mainly formed from one of the microsatellite clusters, the two or four remaining microsatellite clusters form the carrion ecotype. There was slight sexual isolation and a reduction in F1-female offspring between inbreeding strains from the same microsatellite clusters and the same ecotypes. Strains from different microsatellite clusters are separated by a reduction in F1-female offspring. Ecotypes are separated only by ecological barriers.
This is the first demonstration of very early reproductive barriers within a sympatric population of Hymenoptera. It demonstrates that sexual and premating barriers can precede ecological separation. This indicates the complexity of ecotype formation and highlights the general need for more studies within homogenous populations for the identification of the earliest barriers in the speciation process.
A revision of the subgenus Hebena Walker, 1856 of the syntomine genus Metarctia Walker, 1855 is given based on integrative taxonomic analyses. Six new species (Metarctia (Hebena) manfredi sp. n., M. ...(H.) elleni sp. n., M. (H.) brigitta sp. n., M. (H). lukaszi sp. n., M. (H.) smithi sp. n., and M. (H.) haraldsulaki sp.n.) and one new subspecies (M. (H.) smithi transvallesiana ssp. n.) are described. Metarctia (H.) kelleni (Snellen, 1886) stat. rev. is reinstated from synonymy with M. (H.) rubra (Walker, 1856) and Metarctia (H.) subincarnata Kiriakoff, 1954 syn. n. is synonymised with M. (H.) henrardi Kiriakoff, 1953 and Metarctia cinnamomea (Wallengren, 1860) syn. n. with M. (H.) rubra (Walker, 1856). DNA barcodes were obtained for 116 specimens representing 7 taxa, and genetic analyses were performed using Maximum Likelihood and Bayesian Inference approaches; a DNA barcode tree resulting from the latter is illustrated. Pairwise distances of barcodes between taxa are provided where available. The adults and genitalia of all taxa, their habitats and distribution are illustrated in 19 colour plates and 5 distribution maps.
Although changes in gene regulation may play an important role in adaptive evolution, there have been few attempts to investigate the molecular mechanisms responsible for adaptively significant ...variation in gene expression. Here we describe the mechanism underlying an adaptive difference in the expression of the lactate dehydrogenase-B gene (Ldh-B) between northern and southern populations of the fish Fundulus heteroclitus. Ldh-B regulatory sequences from northern and southern individuals, coupled to a luciferase reporter gene, were introduced into the livers of live fish. Deletion studies indicated that sequence changes between 400 and 500 bp upstream of the transcription start site resulted in a 2-fold difference in reporter gene transcription. These sequence changes can account for the previously observed 2-fold difference in Ldh-B transcription between populations. Variation in transcription factors did not play an important role. Sequences within the functionally important region resemble a mammary tumor virus glucocorticoid responsive element (MTV-GRE) in southern alleles, whereas northern alleles differ from the consensus by 1 bp. To test the hypothesis that this element is involved in the variation between populations of F. heteroclitus, we exposed transiently transgenic fish containing Ldh-B regulatory sequence/reporter gene constructs to handling stress or injected cortisol. Both treatments increased reporter gene transcription driven by southern alleles but not northern alleles, as expected if an MTV-GRE sequence were involved. This finding suggests that sequence variation in a GRE is the cause of the adaptive differences in Ldh-B gene expression between populations and demonstrates that small changes in gene regulatory sequences can have important evolutionary consequences.
Burial dating with terrestrial cosmogenic nuclides and luminescence dating techniques have become two powerful tools to temporally constrain Quaternary deposits. A combination of both methods at the ...same geological setting has rarely been realized to date, although their viable time frames overlap by several tens of thousands of years. When Middle Pleistocene sediments with depositional ages ranging around ca. 120 ka to ca. 300 ka are targeted, both methods are employed, but come towards their lower and upper limits, respectively. A combined dating approach can be worthwhile at this age range and allows not only exploring the edges of both methods, but holds the opportunity to do a cross-check of results at an age spectrum, where both dating techniques are at risk to become fuzzy.
Here we present a case study where numerical ages of two Middle Pleistocene terraces located in the Vienna Basin were generated by combining burial and luminescence dating. A variety of processes, such as changing sediment input rates, erosion, and tectonics controlled the formation of fluvial terraces in the basin and shaped its complex modern surface. Age correlation of the evolved mosaic of blocks and dislocated sediment bodies is challenging and requires quantitative geochronological information in order to establish a coherent terrace stratigraphy. Luminescence and burial samples originating from two fluvial terraces, the lower Gaenserndorf terrace (GDT) and the higher Schlosshof terrace (SHT), were analyzed and evaluated. Luminescence and burial ages at the GDT site are in good agreement and suggest a depositional age of 140 ± 170 ka bracketed by pIRIR225 luminescence ages ranging from 120 ± 10 ka to 260 ± 30 ka. Luminescence samples at the SHT site are in saturation, but provide minimum ages, which are coherent with the burial dating result of 340 ± 170 ka. The new numerical ages indicate that the vertical offset between the GDT site and the SHT site was not purely caused by fault activity, but suggest two independent episodes of sediment accumulation.
Besides providing new insights into the stratigraphic and morphological configuration of the central Vienna Basin area, the cosmogenic nuclide data set is compelling from a methodological point of view. At the GDT site, several samples exhibited 26Al/10Be nuclide ratios exceeding the surface production ratio of 6.75. Even though affected samples were excluded from burial age calculations, a detailed investigation on possible scenarios, which could have caused an upwards shift of 26Al/10Be ratios, was carried out.
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