107 research outputs found
Upstream-binding factor is sequestered into herpes simplex virus type 1 replication compartments
Previous reports have shown that adenovirus recruits nucleolar protein upstream-binding factor (UBF) into adenovirus DNA replication centres. Here, we report that despite having a different mode of viral DNA replication, herpes simplex virus type 1 (HSV-1) also recruits UBF into viral DNA replication centres. Moreover, as with adenovirus, enhanced green fluorescent protein-tagged fusion proteins of UBF inhibit viral DNA replication. We propose that UBF is recruited to the replication compartments to aid replication of HSV-1 DNA. In addition, this is a further example of the role of nucleolar components in viral life cycle
Entanglement of trapped-ion qubits separated by 230 meters
We report on an elementary quantum network of two atomic ions separated by
230 m. The ions are trapped in different buildings and connected with 520(2) m
of optical fiber. At each network node, the electronic state of an ion is
entangled with the polarization state of a single cavity photon; subsequent to
interference of the photons at a beamsplitter, photon detection heralds
entanglement between the two ions. Fidelities of up to are
achieved with respect to a maximally entangled Bell state, with a success
probability of . We analyze the routes to improve these
metrics, paving the way for long-distance networks of entangled quantum
processors
Cell cycle-dependent acetylation of Rb2/p130 in NIH3T3 cells
The retinoblastoma protein (pRb) and the pRb-related proteins, p130 and p107, form the ‘pocket protein' family of cell cycle regulatory factors. A well characterized function of these proteins is the cell cycle-dependent regulation of E2F-responsive genes. The biological activity of pocket proteins is regulated by phosphorylation and for the founding member pRb it has been shown that acetylation also has an important role in modulating its function during the cell cycle. Here, we show that hyperphosphorylated retinoblastoma 2 (Rb2)/p130 also exists in an acetylated form in NIH3T3 cells. Acetylated p130 is present in the nucleus but not in the cytoplasm. Acetylation is cell cycle dependent, starting in S-phase and persisting until late G2-period. Using recombinant p130 and truncated forms for in vitro acetylation by the acetyltransferase p300, we could identify K1079 in the C-terminal part as the major acetylation site by mass spectrometry. Minor acetylation sites were pinpointed to K1068 and K1111 in the C-terminus, and K128 and K130 in the N-terminus. The human papilloma virus 16 protein-E7 preferentially binds to acetylated p130 and significantly increases in vitro p130 acetylation by p300
The Effect of Recurrent Floods on Genetic Composition of Marble Trout Populations
A changing global climate can threaten the diversity of species and ecosystems. We explore the consequences of catastrophic disturbances in determining the evolutionary and demographic histories of secluded marble trout populations in Slovenian streams subjected to weather extremes, in particular recurrent flash floods and debris flows causing massive mortalities. Using microsatellite data, a pattern of extreme genetic differentiation was found among populations (global FST of 0.716), which exceeds the highest values reported in freshwater fish. All locations showed low levels of genetic diversity as evidenced by low heterozygosities and a mean of only 2 alleles per locus, with few or no rare alleles. Many loci showed a discontinuous allele distribution, with missing alleles across the allele size range, suggestive of a population contraction. Accordingly, bottleneck episodes were inferred for all samples with a reduction in population size of 3–4 orders of magnitude. The reduced level of genetic diversity observed in all populations implies a strong impact of genetic drift, and suggests that along with limited gene flow, genetic differentiation might have been exacerbated by recurrent mortalities likely caused by flash flood and debris flows. Due to its low evolutionary potential the species might fail to cope with an intensification and altered frequency of flash flood events predicted to occur with climate change
HEPPA-II model-measurement intercomparison project : EPP indirect effects during the dynamically perturbed NH winter 2008-2009
We compare simulations from three high-top (with upper lid above 120 km) and five medium-top (with upper lid around 80 km) atmospheric models with observations of odd nitrogen (NOx D NO+NO2), temperature, and carbon monoxide from seven satellite instruments (ACE-FTS on SciSat, GOMOS, MIPAS, and SCIAMACHY on Envisat, MLS on Aura, SABER on TIMED, and SMR on Odin) during the Northern Hemisphere (NH) polar winter 2008/2009. The models included in the comparison are the 3-D chemistry transport model 3dCTM, the ECHAM5/MESSy Atmospheric Chemistry (EMAC) model, FinROSE, the Hamburg Model of the Neutral and Ionized Atmosphere (HAMMO-NIA), the Karlsruhe Simulation Model of the Middle Atmosphere (KASIMA), the modelling tools for SOlar Climate Ozone Links studies (SOCOL and CAO-SOCOL), and the Whole Atmosphere Community Climate Model (WACCM4). The comparison focuses on the energetic particle precipitation (EPP) indirect effect, that is, the polar winter descent of NOx largely produced by EPP in the mesosphere and lower thermosphere. A particular emphasis is given to the impact of the sudden stratospheric warming (SSW) in January 2009 and the subsequent elevated stratopause (ES) event associated with enhanced descent of mesospheric air. The chemistry climate model simulations have been nudged toward reanalysis data in the troposphere and stratosphere while being unconstrained above. An odd nitrogen upper boundary condition obtained from MIPAS observations has further been applied to medium-top models. Most models provide a good representation of the mesospheric tracer descent in general, and the EPP indirect effect in particular, during the unperturbed (pre-SSW) period of the NH winter 2008/2009. The observed NOx descent into the lower mesosphere and stratosphere is generally reproduced within 20 %. Larger discrepancies of a few model simulations could be traced back either to the impact of the models' gravity wave drag scheme on the polar wintertime meridional circulation or to a combination of prescribed NOx mixing ratio at the uppermost model layer and low vertical resolution. In March-April, after the ES event, however, modelled mesospheric and stratospheric NOx distributions deviate significantly from the observations. The too-fast and early downward propagation of the NO x tongue, encountered in most simulations, coincides with a temperature high bias in the lower mesosphere (0.2-0.05 hPa), likely caused by an overestimation of descent velocities. In contrast, upper-mesospheric temperatures (at 0.05-0.001 hPa) are generally underestimated by the high-top models after the onset of the ES event, being indicative for too-slow descent and hence too-low NOx fluxes. As a consequence, the magnitude of the simulated NOx tongue is generally underestimated by these models. Descending NOx amounts simulated with mediumtop models are on average closer to the observations but show a large spread of up to several hundred percent. This is primarily attributed to the different vertical model domains in which the NOx upper boundary condition is applied. In general, the intercomparison demonstrates the ability of state-of- the-art atmospheric models to reproduce the EPP indirect effect in dynamically and geomagnetically quiescent NH winter conditions. The encountered differences between observed and simulated NOx, CO, and temperature distributions during the perturbed phase of the 2009 NH winter, however, emphasize the need for model improvements in the dynamical representation of elevated stratopause events in order to allow for a better description of the EPP indirect effect under these particular conditions.Peer reviewe
Postglacial recolonizations, watershed crossings and human translocations shape the distribution of chub lineages around the Swiss Alps
HEPPA-II model–measurement intercomparison project: EPP indirect effects during the dynamically perturbed NH winter 2008-2009
We compare simulations from three high-top (with upper lid above 120 km) and five medium-top (with upper lid around 80 km) atmospheric models with observations of odd nitrogen (NOx = NO + NO2), temperature, and carbon monoxide from seven satellite instruments (ACE-FTS on SciSat, GOMOS, MIPAS, and SCIAMACHY on Envisat, MLS on Aura, SABER on TIMED, and SMR on Odin) during the Northern Hemisphere (NH) polar winter 2008/2009. The models included in the comparison are the 3-D chemistry transport model 3dCTM, the ECHAM5/MESSy Atmospheric Chemistry (EMAC) model, FinROSE, the Hamburg Model of the Neutral and Ionized Atmosphere (HAMMONIA), the Karlsruhe Simulation Model of the Middle Atmosphere (KASIMA), the modelling tools for SOlar Climate Ozone Links studies (SOCOL and CAO-SOCOL), and the Whole Atmosphere Community Climate Model (WACCM4). The comparison focuses on the energetic particle precipitation (EPP) indirect effect, that is, the polar winter descent of NOx largely produced by EPP in the mesosphere and lower thermosphere. A particular emphasis is given to the impact of the sudden stratospheric warming (SSW) in January 2009 and the subsequent elevated stratopause (ES) event associated with enhanced descent of mesospheric air. The chemistry climate model simulations have been nudged toward reanalysis data in the troposphere and stratosphere while being unconstrained above. An odd nitrogen upper boundary condition obtained from MIPAS observations has further been applied to medium-top models. Most models provide a good representation of the mesospheric tracer descent in general, and the EPP indirect effect in particular, during the unperturbed (pre-SSW) period of the NH winter 2008/2009. The observed NOx descent into the lower mesosphere and stratosphere is generally reproduced within 20 %. Larger discrepancies of a few model simulations could be traced back either to the impact of the models\u27 gravity wave drag scheme on the polar wintertime meridional circulation or to a combination of prescribed NOx mixing ratio at the uppermost model layer and low vertical resolution. In March–April, after the ES event, however, modelled mesospheric and stratospheric NOx distributions deviate significantly from the observations. The too-fast and early downward propagation of the NOx tongue, encountered in most simulations, coincides with a temperature high bias in the lower mesosphere (0.2–0.05 hPa), likely caused by an overestimation of descent velocities. In contrast, upper-mesospheric temperatures (at 0.05–0.001 hPa) are generally underestimated by the high-top models after the onset of the ES event, being indicative for too-slow descent and hence too-low NOx fluxes. As a consequence, the magnitude of the simulated NOx tongue is generally underestimated by these models. Descending NOx amounts simulated with medium-top models are on average closer to the observations but show a large spread of up to several hundred percent. This is primarily attributed to the different vertical model domains in which the NOx upper boundary condition is applied. In general, the intercomparison demonstrates the ability of state-of-the-art atmospheric models to reproduce the EPP indirect effect in dynamically and geomagnetically quiescent NH winter conditions. The encountered differences between observed and simulated NOx, CO, and temperature distributions during the perturbed phase of the 2009 NH winter, however, emphasize the need for model improvements in the dynamical representation of elevated stratopause events in order to allow for a better description of the EPP indirect effect under these particular conditions
The climate of a retrograde rotating Earth
To enhance understanding of Earth's climate, numerical experiments are
performed contrasting a retrograde and prograde rotating Earth using the Max
Planck Institute Earth system model. The experiments show that the sense of
rotation has relatively little impact on the globally and zonally averaged
energy budgets but leads to large shifts in continental climates, patterns
of precipitation, and regions of deep water formation.Changes in the zonal asymmetries of the continental climates are expected
given ideas developed more than a hundred years ago. Unexpected was, however,
the switch in the character of the European–African climate with that of the
Americas, with a drying of the former and a greening of the latter. Also
unexpected was a shift in the storm track activity from the oceans to the
land in the Northern Hemisphere. The different patterns of storms and changes
in the direction of the trades influence fresh water transport, which may
underpin the change of the role of the North Atlantic and the Pacific in
terms of deep water formation, overturning and northward oceanic heat
transport. These changes greatly influence northern hemispheric climate and
atmospheric heat transport by eddies in ways that appear energetically
consistent with a southward shift of the zonally and annually averaged
tropical rain bands. Differences between the zonally averaged energy budget
and the rain band shifts leave the door open, however, for an important role
for stationary eddies in determining the position of tropical rains. Changes
in ocean biogeochemistry largely follow shifts in ocean circulation, but the
emergence of a super oxygen minimum zone in the Indian Ocean is not
expected. The upwelling of phosphate-enriched and nitrate-depleted water
provokes a dominance of cyanobacteria over bulk phytoplankton over vast areas – a phenomenon not observed in the prograde model.What would the climate of Earth look like if it would rotate in the reversed
(retrograde) direction? Which of the characteristic climate patterns in the
ocean, atmosphere, or land that are observed in a present-day climate are the
result of the direction of Earth's rotation? Is, for example, the structure
of the oceanic meridional overturning circulation (MOC) a consequence of the
interplay of basin location and rotation direction? In experiments with the
Max Planck Institute Earth system model (MPI-ESM), we investigate the effects
of a retrograde rotation in all aspects of the climate system.The expected consequences of a retrograde rotation are reversals of the zonal
wind and ocean circulation patterns. These changes are associated with major
shifts in the temperature and precipitation patterns. For example, the
temperature gradient between Europe and eastern Siberia is reversed, and the
Sahara greens, while large parts of the Americas become deserts.
Interestingly, the Intertropical Convergence Zone (ITCZ) shifts southward and
the modeled double ITCZ in the Pacific changes to a single ITCZ, a result of
zonal asymmetries in the structure of the tropical circulation.One of the most prominent non-trivial effects of a retrograde rotation is a
collapse of the Atlantic MOC, while a strong overturning cell emerges in the
Pacific. This clearly shows that the position of the MOC is not controlled by
the sizes of the basins or by mountain chains splitting the continents in
unequal runoff basins but by the location of the basins relative to the
dominant wind directions. As a consequence of the changes in the ocean
circulation, a super oxygen minimum zone develops in the Indian Ocean
leading to upwelling of phosphate-enriched and nitrate-depleted water. These
conditions provoke a dominance of cyanobacteria over bulk phytoplankton over
vast areas, a phenomenon not observed in the prograde model.</p
A review of progress towards understanding the transient global mean surface temperature response to radiative perturbation
Biological and trophic consequences of genetic introgression between endemic and invasive Barbus fishes.
Genetic introgression with native species is recognized as a detrimental impact resulting from biological invasions involving taxonomically similar invaders. Whilst the underlying genetic mechanisms are increasingly understood, the ecological consequences of introgression are relatively less studied, despite their utility for increasing knowledge on how invasion impacts can manifest. Here, the ecological consequences of genetic introgression from an invasive congener were tested using the endemic barbel populations of central Italy, where the invader was the European barbel Barbus barbus. Four populations of native Barbus species (B. plebejus and B. tyberinus) were studied: two purebred and two completely introgressed with alien B. barbus. Across the four populations, differences in their biological traits (growth, body condition and population demographic structure) and trophic ecology (gut content analysis and stable isotope analysis) were tested. While all populations had similar body condition and were dominated by fish up to 2 years of age, the introgressed fish had substantially greater lengths at the same age, with maximum lengths 410-460 mm in hybrids versus 340-360 mm in native purebred barbel. The population characterized by the highest number of introgressed B. barbus alleles (81 %) had the largest trophic niche and a substantially lower trophic position than the other populations through its exploitation of a wider range of resources (e.g. small fishes and plants). These results attest that the genetic introgression of an invasive congener with native species can result in substantial ecological consequences, including the potential for cascading effects. Supplementary Information: The online version contains supplementary material available at 10.1007/s10530-021-02577-6
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