ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Oxford University Press  (24)
  • Frontiers Media  (2)
  • 2010-2014  (26)
  • 1970-1974
  • 1965-1969
  • 1930-1934
  • 2014  (26)
  • 1
    facet.materialart.
    Unknown
    Molecular Characterization and Evolution of a Gene Family Encoding Both Female- and Male-Specific Reproductive Proteins in Drosophila (2014)
    Oxford University Press
    Details
    Publication Date: 2014-05-24
    Description: Gene duplication is an important mechanism for the evolution of new reproductive proteins. However, in most cases, each resulting paralog continues to function within the same sex. To investigate the possibility that seminal fluid proteins arise through duplicates of female reproductive genes that become "co-opted" by males, we screened female reproductive genes in Drosophila melanogaster for cases of duplication in which one of the resulting paralogs produces a protein in males that is transferred to females during mating. We identified a set of three tandemly duplicated genes that encode secreted serine-type endopeptidase homologs, two of which are expressed primarily in the female reproductive tract (RT), whereas the third is expressed specifically in the male RT and encodes a seminal fluid protein. Evolutionary and gene expression analyses across Drosophila species suggest that this family arose from a single-copy gene that was female-specific; after duplication, one paralog evolved male-specific expression. Functional tests of knockdowns of each gene in D. melanogaster show that one female-expressed gene is essential for full fecundity, and both female-expressed genes contribute singly or in combination to a female’s propensity to remate. In contrast, knockdown of the male-expressed paralog had no significant effect on female fecundity or remating. These data are consistent with a model in which members of this gene family exert effects on females by acting on a common, female-expressed target. After duplication and male co-option of one paralog, the evolution of the interacting proteins could have resulted in differential strengths or effects of each paralog.
    Print ISSN: 0737-4038
    Electronic ISSN: 1537-1719
    Topics: Biology
    Published by Oxford University Press
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 2
    facet.materialart.
    Unknown
    Network topology reveals high connectance levels and few key microbial genera within soils (2014)
    Frontiers Media
    Details
    Publication Date: 2014-05-08
    Electronic ISSN: 2296-665X
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Published by Frontiers Media
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 3
    facet.materialart.
    Unknown
    Synthesis, biophysical properties and biological activity of second generation antisense oligonucleotides containing chiral phosphorothioate linkages (2014)
    Oxford University Press
    Details
    Publication Date: 2014-12-17
    Description: Bicyclic oxazaphospholidine monomers were used to prepare a series of phosphorothioate (PS)-modified gapmer antisense oligonucleotides (ASOs) with control of the chirality of each of the PS linkages within the 10-base gap. The stereoselectivity was determined to be 98% for each coupling. The objective of this work was to study how PS chirality influences biophysical and biological properties of the ASO including binding affinity ( T m ), nuclease stability, activity in vitro and in vivo , RNase H activation and cleavage patterns (both human and E. coli ) in a gapmer context. Compounds that had nine or more Sp-linkages in the gap were found to be poorly active in vitro , while compounds with uniform Rp-gaps exhibited activity very similar to that of the stereo-random parent ASOs. Conversely, when tested in vivo , the full Rp-gap compound was found to be quickly metabolized resulting in low activity. A total of 31 ASOs were prepared with control of the PS chirally of each linkage within the gap in an attempt to identify favorable Rp/Sp positions. We conclude that a mix of Rp and Sp is required to achieve a balance between good activity and nuclease stability.
    Print ISSN: 0305-1048
    Electronic ISSN: 1362-4962
    Topics: Biology
    Published by Oxford University Press
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 4
    facet.materialart.
    Unknown
    Characterization of the meningococcal serogroup X capsule N-acetylglucosamine-1-phosphotransferase (2014)
    Oxford University Press
    Details
    Publication Date: 2014-01-24
    Description: Neisseria meningitidis serogroups A, B, C, Y, W135 and X are responsible for most cases of meningococcal meningitis. Neisseria meningitidis serogroup X has recently emerged as a contributor to outbreaks of disease in Africa, but there is currently no vaccine against serogroup X. Understanding of the biosynthesis of the serogroup X capsular polysaccharide would provide useful tools for vaccine production. The serogroup X polysaccharide is a homopolymer of (α1-〉4)-linked N -acetylglucosamine (GlcNAc)-1-phosphate. It has been shown that the gene cluster xcb ABC encodes synthesis of this polysaccharide. The xcbA gene product has significant homology with sac B, which is responsible for synthesis of the Neisseria serogroup A capsular polysaccharide, an (α1-〉6)- N -acetylmannosamine-1-phosphate homopolymer. The xcbA protein also shares homology with the catalytic domain of human N -acetylglucosamine-1-phosphoryltransferase, a key enzyme in the mannose-6-phosphate receptor pathway. In this study, we show that xcbA in the appropriate background is sufficient for the synthesis of N. meningitidis serogroup X polysaccharide. By ELISA we detected polysaccharide in fractions of Escherichia coli expressing the xcbA gene. We isolated polysaccharide from an E. coli strain expressing XcbA and demonstrated that this polysaccharide has a 13 C-NMR spectrum identical to that of polysaccharide isolated from N. meningitidis Group X. We also demonstrate that the purified XcbA protein is an N -acetylglucosamine-1-phosphotransferase that transfers N -acetylglucosamine-1-phosphate from UDP-GlcNAc to the 4-hydroxyl of an N -acetylglucosamine-1-phosphate oligosaccharide. Oligosaccharides fluorescently labeled at the aglycon are extended by XcbA only after the 4-phosphate occupying the non-reducing GlcNAc has been removed. The minimum size of fluorescent acceptors is a trisaccharide.
    Print ISSN: 0959-6658
    Electronic ISSN: 1460-2423
    Topics: Biology , Medicine
    Published by Oxford University Press
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 5
    facet.materialart.
    Unknown
    Signatures of warm carbon monoxide in protoplanetary discs observed with Herschel SPIRE (2014)
    Oxford University Press
    Details
    Publication Date: 2014-09-20
    Description: Molecular gas constitutes the dominant mass component of protoplanetary discs. To date, these sources have not been studied comprehensively at the longest far-infrared and shortest submillimetre wavelengths. This paper presents Herschel SPIRE FTS spectroscopic observations towards 18 protoplanetary discs, covering the entire 450–1540 GHz (666–195 μm) range at / 400–1300. The spectra reveal clear detections of the dust continuum and, in six targets, a significant amount of spectral line emission primarily attributable to 12 CO rotational lines. Other targets exhibit little to no detectable spectral lines. Low signal-to-noise detections also include signatures from 13 CO, [C i ] and HCN. For completeness, we present upper limits of non-detected lines in all targets, including low-energy transitions of H 2 O and CH + molecules. The 10 12 CO lines that fall within the SPIRE FTS bands trace energy levels of ~50–500 K. Combined with lower and higher energy lines from the literature, we compare the CO rotational line energy distribution with detailed physical–chemical models, for sources where these are available and published. Our 13 CO line detections in the disc around Herbig Be star HD 100546 exceed, by factors of ~10–30, the values predicted by a model that matches a wealth of other observational constraints, including the SPIRE 12 CO ladder. To explain the observed 12 CO/ 13 CO ratio, it may be necessary to consider the combined effects of optical depth and isotope selective (photo)chemical processes. Considering the full sample of 18 objects, we find that the strongest line emission is observed in discs around Herbig Ae/Be stars, although not all show line emission. In addition, two of the six T Tauri objects exhibit detectable 12 CO lines in the SPIRE range.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
    Published by Oxford University Press
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 6
    facet.materialart.
    Unknown
    A neutrino model fit to the CMB power spectrum (2014)
    Oxford University Press
    Details
    Publication Date: 2014-10-22
    Description: The standard cosmological model, cold dark matter (CDM), provides an excellent fit to cosmic microwave background (CMB) data. However, the model has well-known problems. For example, the cosmological constant, , is fine-tuned to 1 part in 10 100 and the CDM particle is not yet detected in the laboratory. Shanks previously investigated a model which assumed neither exotic particles nor a cosmological constant but instead postulated a low Hubble constant ( H 0 ) to allow a baryon density compatible with inflation and zero spatial curvature. However, recent Planck results make it more difficult to reconcile such a model with CMB power spectra. Here, we relax the previous assumptions to assess the effects of assuming three active neutrinos of mass 5 eV. If we assume a low H 0   45 km s –1  Mpc –1 then, compared to the previous purely baryonic model, we find a significantly improved fit to the first three peaks of the Planck power spectrum. Nevertheless, the goodness of fit is still significantly worse than for CDM and would require appeal to unknown systematic effects for the fit ever to be considered acceptable. A further serious problem is that the amplitude of fluctuations is low ( 8   0.2), making it difficult to form galaxies by the present day. This might then require seeds, perhaps from a primordial magnetic field, to be invoked for galaxy formation. These and other problems demonstrate the difficulties faced by models other than CDM in fitting ever more precise cosmological data.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
    Published by Oxford University Press
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 7
    facet.materialart.
    Unknown
    The formation of stellar nuclear discs in bar-induced gas inflows (2014)
    Oxford University Press
    Details
    Publication Date: 2014-10-31
    Description: The role of gas in the mass assembly at the nuclei of galaxies is still subject to some uncertainty. Stellar nuclear discs bridge the gap between the large-scale galaxy and the central massive objects that reside there. Using a high-resolution simulation of a galaxy forming out of gas cooling and settling into a disc, we study the formation and properties of nuclear discs. Gas, driven to the centre by a bar, settles into a rotating star-forming nuclear disc (ND). This ND is thinner, younger, kinematically cooler and more metal rich than the surrounding bar. The ND is elliptical and orthogonal to the bar. The complex kinematics in the region of the ND are a result of the superposition of older stars streaming along the bar and younger stars circulating within the ND. The signature of the ND is therefore subtle in the kinematics. Instead the ND stands out clearly in metallicity and age maps. We compare the model to the density and kinematics of real galaxies with NDs finding qualitative similarities. Our results suggest that gas dissipation is very important for forming nuclear structures.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
    Published by Oxford University Press
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 8
    facet.materialart.
    Unknown
    SMBE Satellite Meeting on Reticulated Microbial Evolution 2014--Meeting Report (2014)
    Oxford University Press
    Details
    Publication Date: 2014-09-13
    Electronic ISSN: 1759-6653
    Topics: Biology
    Published by Oxford University Press
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 9
    facet.materialart.
    Unknown
    Functional kleptoplasty in a limapontioidean genus: phylogeny, food preferences and photosynthesis in Costasiella, with a focus on C. ocellifera (Gastropoda: Sacoglossa) (2014)
    Oxford University Press
    Details
    Publication Date: 2014-12-10
    Description: The evolution and origin of functional kleptoplasty (sequestration and retention of functional plastids) within the Sacoglossa is still controversial. While some authors have suggested that it is a synapomorphy of the parapodia-bearing Plakobranchoidea, others have suggested an earlier origin at the base of the more inclusive clade Plakobranchacea. The latter is supported by the presence of kleptoplasts in Costasiella ocellifera , a ceras-bearing member of Limapontioidea, in which they remain functional for several weeks and fix CO 2 . However, the phylogenetic relationships of Costasiella , especially with regard to the Plakobranchoidea, have not been satisfactorily demonstrated, and the photosynthetic ability and the importance of photosynthesis within the genus remain poorly studied. In this study we analyse the phylogenetic position, photosynthetic activity and importance of photosynthesis for survival during starvation of five Costasiella species, but focusing on C. ocellifera . We demonstrate that Costasiella is a basal member of the Limapontioidea, however a final conclusion on the origin of functional kleptoplasty within Sacoglossa is still not possible. Three Costasiella species maintain functional chloroplasts (of which C. ocellifera shows long-term retention, and both C. kuroshimae and C. sp. 1 short-term retention) and together form a monophyletic group, feeding mainly on Avrainvillea . The two nonphotosynthetic species, C. nonatoi and C. sp. 2, represent the sister clade and feed on algae other than Avrainvillea . Intriguingly, C. ocellifera survived under nonphotosynthetic conditions for a minimum of 38 d, demonstrating that photosynthates may not be essential in order to survive starvation. These findings support our previous suggestion that during starvation kleptoplasts primarily represent a sort of larder, whose function might benefit from ongoing photosynthesis.
    Print ISSN: 0260-1230
    Electronic ISSN: 1464-3766
    Topics: Biology
    Published by Oxford University Press
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 10
    facet.materialart.
    Unknown
    Cyclonic entrainment? The ichthyoplankton attributes of three major water mass types generated by the separation of the East Australian Current (2014)
    Oxford University Press
    Details
    Publication Date: 2014-09-30
    Description: The relationship between larval fish assemblages and coastal oceanography is the basis for much of our understanding of connectivity and productivity of fish populations. Larval fish assemblages were sampled from the upper mixed layer (〈50 m depth) at three prominent circulation features [separation of the East Australian Current (EAC), anticyclonic eddy, and cyclonic eddy] off the southeast Australian coast across three bathymetric zones (shelf, slope and ocean) for each feature. The separation of the EAC from the coast at ~32°S was characterized by warmer, less saline water compared with the cyclonic and anticyclonic eddies further to the south (~34 and ~35°S, respectively), which were both characterized by cooler Tasman Sea water and greater fluorescence. The anticyclonic eddy had separated from the EAC three months prior to sampling, which facilitated the movement of a cyclonic eddy from the Tasman Sea westwards to the shelf at ~34°S. The larval assemblage in the EAC had high numbers of fish of the families Labridae and Stomiidae. The cyclonic eddy was characterized by larval clupeids, carangids, scombrids and bothids, indicating recent entrainment of shelf waters and proximity to major spawning regions. In contrast, the anticyclonic eddy had fewer larval fish, with little evidence for entrainment of shelf assemblages into the near-surface waters. Myctophids were found in high abundance across all oceanographic features and bathymetric zones. The evidence of selective entrainment of coastal larval fish into the near-surface waters of a cyclonic eddy compared with a similar anticyclonic eddy indicates a potential offshore nursery ground.
    Print ISSN: 1054-3139
    Electronic ISSN: 1095-9289
    Topics: Biology , Geosciences , Physics
    Published by Oxford University Press
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...