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991.
Miriam Ehrnthaler Lars B. Scharff Tobias T. Fleischmann Claudia Hasse Stephanie Ruf Ralph Bock 《The Plant cell》2014,26(2):765-776
Consistent with their origin from cyanobacteria, plastids (chloroplasts) perform
protein biosynthesis on bacterial-type 70S ribosomes. The plastid genomes of seed
plants contain a conserved set of ribosomal protein genes. Three of these have proven
to be nonessential for translation and, thus, for cellular viability:
rps15, rpl33, and rpl36. To
help define the minimum ribosome, here, we examined whether more than one of these
nonessential plastid ribosomal proteins can be removed from the 70S ribosome. To that
end, we constructed all possible double knockouts for the S15, L33, and L36 ribosomal
proteins by stable transformation of the tobacco (Nicotiana tabacum)
plastid genome. We find that, although S15 and L33 function in different ribosomal
particles (30S and 50S, respectively), their combined deletion from the plastid
genome results in synthetic lethality under autotrophic conditions. Interestingly,
the lethality can be overcome by growth under elevated temperatures due to an
improved efficiency of plastid ribosome biogenesis. Our results reveal functional
interactions between protein and RNA components of the 70S ribosome and uncover the
interdependence of the biogenesis of the two ribosomal subunits. In addition, our
findings suggest that defining a minimal set of plastid genes may prove more complex
than generally believed. 相似文献
992.
Tobias Maierhofer Christof Lind Stefanie Hüttl S?nke Scherzer Melanie Papenfu? Judy Simon Khaled A.S. Al-Rasheid Peter Ache Heinz Rennenberg Rainer Hedrich Thomas D. Müller Dietmar Geiger 《The Plant cell》2014,26(6):2554-2567
In contrast to animal cells, plants use nitrate as a major source of nitrogen.
Following the uptake of nitrate, this major macronutrient is fed into the vasculature
for long-distance transport. The Arabidopsis thaliana shoot
expresses the anion channel SLOW ANION CHANNEL1 (SLAC1) and its homolog SLAC1
HOMOLOGOUS3 (SLAH3), which prefer nitrate as substrate but cannot exclude chloride
ions. By contrast, we identified SLAH2 as a nitrate-specific channel that is
impermeable for chloride. To understand the molecular basis for nitrate selection in
the SLAH2 channel, SLAC1 and SLAH2 were modeled to the structure of HiTehA, a
distantly related bacterial member. Structure-guided site-directed mutations
converted SLAC1 into a SLAH2-like nitrate-specific anion channel and vice versa. Our
findings indicate that two pore-occluding phenylalanines constrict the pore. The
selectivity filter of SLAC/SLAH anion channels is determined by the polarity of
pore-lining residues located on alpha helix 3. Changing the polar character of a
single amino acid side chain (Ser-228) to a nonpolar residue turned the
nitrate-selective SLAH2 into a chloride/nitrate-permeable anion channel. Thus, the
molecular basis of the anion specificity of SLAC/SLAH anion channels seems to be
determined by the presence and constellation of polar side chains that act in concert
with the two pore-occluding phenylalanines. 相似文献
993.
Florian Fr?hlich Romain Christiano Daniel K. Olson Abel Alcazar-Roman Pietro DeCamilli Tobias C. Walther 《Molecular biology of the cell》2014,25(18):2797-2806
The plasma membrane delineates the cell and mediates its communication and material exchange with the environment. Many processes of the plasma membrane occur through interactions of proteins with phosphatidylinositol(4,5)-bisphosphate (PI(4,5)P2), which is highly enriched in this membrane and is a key determinant of its identity. Eisosomes function in lateral organization of the plasma membrane, but the molecular function of their major protein subunits, the BAR domain–containing proteins Pil1 and Lsp1, is poorly understood. Here we show that eisosomes interact with the PI(4,5)P2 phosphatase Inp51/Sjl1, thereby recruiting it to the plasma membrane. Pil1 is essential for plasma membrane localization and function of Inp51 but not for the homologous phosphatidylinositol bisphosphate phosphatases Inp52/Sjl2 and Inp53/Sjl3. Consistent with this, absence of Pil1 increases total and available PI(4,5)P2 levels at the plasma membrane. On the basis of these findings, we propose a model in which the eisosomes function in maintaining PI(4,5)P2 levels by Inp51/Sjl1 recruitment. 相似文献
994.
995.
Katharina V. Alheit Lucas Busemeyer Wenxin Liu Hans Peter Maurer Manje Gowda Volker Hahn Sigrid Weissmann Arno Ruckelshausen Jochen C. Reif Tobias Würschum 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2014,127(1):251-260
Key message
QTL mapping in multiple families identifies trait-specific and pleiotropic QTL for biomass yield and plant height in triticale.Abstract
Triticale shows a broad genetic variation for biomass yield which is of interest for a range of purposes, including bioenergy. Plant height is a major contributor to biomass yield and in this study, we investigated the genetic architecture underlying biomass yield and plant height by multiple-line cross QTL mapping. We employed 647 doubled haploid lines from four mapping populations that have been evaluated in four environments and genotyped with 1710 DArT markers. Twelve QTL were identified for plant height and nine for biomass yield which cross-validated explained 59.6 and 38.2 % of the genotypic variance, respectively. A major QTL for both traits was identified on chromosome 5R which likely corresponds to the dominant dwarfing gene Ddw1. In addition, we detected epistatic QTL for plant height and biomass yield which, however, contributed only little to the genetic architecture of the traits. In conclusion, our results demonstrate the potential of genomic approaches for a knowledge-based improvement of biomass yield in triticale. 相似文献996.
María Flor García-Mayoral Miguel Angel Trevi?o Teresa Pérez-Pi?ar María Luisa Caballero Tobias Knaute Ana Umpierrez Marta Bruix Rosa Rodríguez-Pérez 《PLoS neglected tropical diseases》2014,8(3)
Background
Anisakiasis is a re-emerging global disease caused by consumption of raw or lightly cooked fish contaminated with L3 Anisakis larvae. This zoonotic disease is characterized by severe gastrointestinal and/or allergic symptoms which may misdiagnosed as appendicitis, gastric ulcer or other food allergies.The Anisakis allergen Ani s 5 is a protein belonging to the SXP/RAL-2 family; it is detected exclusively in nematodes. Previous studies showed that SXP/RAL-2 proteins are active antigens; however, their structure and function remain unknown.The aim of this study was to elucidate the three-dimensional structure of Ani s 5 and its main IgE and IgG4 binding regions.Methodology/Principal Findings
The tertiary structure of recombinant Ani s 5 in solution was solved by nuclear magnetic resonance. Mg2+, but not Ca2+, binding was determined by band shift using SDS-PAGE. IgE and IgG4 epitopes were elucidated by microarray immunoassay and SPOTs membranes using sera from nine Anisakis allergic patients.The tertiary structure of Ani s 5 is composed of six alpha helices (H), with a Calmodulin like fold. H3 is a long, central helix that organizes the structure, with H1 and H2 packing at its N-terminus and H4 and H5 packing at its C-terminus. The orientation of H6 is undefined. Regarding epitopes recognized by IgE and IgG4 immunoglobulins, the same eleven peptides derived from Ani s 5 were bound by both IgE and IgG4. Peptides 14 (L40-K59), 26 (A76-A95) and 35 (I103-D122) were recognized by three out of nine sera.Conclusions/Significance
This is the first reported 3D structure of an Anisakis allergen. Magnesium ion binding and structural resemblance to Calmodulin, suggest some putative functions for SXP/RAL-2 proteins. Furthermore, the IgE/IgG4 binding regions of Ani s 5 were identified as segments localized on its surface. These data will contribute towards a better understanding of the interactions that occur between immunoglobulins and allergens and, in turn, facilitate the design of novel diagnostic tests and immunotherapeutic strategies. 相似文献997.
Nana Ama Amissah Sophie Gryseels Nicholas J. Tobias Bahram Ravadgar Mitsuko Suzuki Koen Vandelannoote Lies Durnez Herwig Leirs Timothy P. Stinear Fran?oise Portaels Anthony Ablordey Miriam Eddyani 《PLoS neglected tropical diseases》2014,8(9)
Background
The reservoir and mode of transmission of Mycobacterium ulcerans, the causative agent of Buruli ulcer, still remain a mystery. It has been suggested that M. ulcerans persists with difficulty as a free-living organism due to its natural fragility and inability to withstand exposure to direct sunlight, and thus probably persists within a protective host environment.Methodology/Principal Findings
We investigated the role of free-living amoebae as a reservoir of M. ulcerans by screening the bacterium in free-living amoebae (FLA) cultures isolated from environmental specimens using real-time PCR. We also followed the survival of M. ulcerans expressing green fluorescence protein (GFP) in Acanthameoba castellanii by flow cytometry and observed the infected cells using confocal and transmission electron microscopy for four weeks in vitro. IS2404 was detected by quantitative PCR in 4.64% of FLA cultures isolated from water, biofilms, detritus and aerosols. While we could not isolate M. ulcerans, 23 other species of mycobacteria were cultivated from inside FLA and/or other phagocytic microorganisms. Laboratory experiments with GFP-expressing M. ulcerans in A. castellani trophozoites for 28 days indicated the bacteria did not replicate inside amoebae, but they could remain viable at low levels in cysts. Transmission electron microscopy of infected A. castellani confirmed the presence of bacteria within both trophozoite vacuoles and cysts. There was no correlation of BU notification rate with detection of the IS2404 in FLA (r = 0.07, n = 539, p = 0.127).Conclusion/Significance
This study shows that FLA in the environment are positive for the M. ulcerans insertion sequence IS2404. However, the detection frequency and signal strength of IS2404 positive amoabae was low and no link with the occurrence of BU was observed. We conclude that FLA may host M. ulcerans at low levels in the environment without being directly involved in the transmission to humans. 相似文献998.
Background
A recent report from the British Nuffield Council on Bioethics associated ‘emerging biotechnologies’ with a threefold challenge: 1) uncertainty about outcomes, 2) diverse public views on the values and implications attached to biotechnologies and 3) the possibility of creating radical changes regarding societal relations and practices. To address these challenges, leading international institutions stress the need for public involvement activities (PIAs). The objective of this study was to assess the state of PIA reports in the field of biomedical research.Methods
PIA reports were identified via a systematic literature search. Thematic text analysis was employed for data extraction.Results
After filtering, 35 public consultation and 11 public participation studies were included in this review. Analysis and synthesis of all 46 PIA studies resulted in 6 distinguishable PIA objectives and 37 corresponding PIA methods. Reports of outcome translation and PIA evaluation were found in 9 and 10 studies respectively (20% and 22%). The paper presents qualitative details.Discussion
The state of PIAs on biomedical research and innovation is characterized by a broad range of methods and awkward variation in the wording of objectives. Better comparability of PIAs might improve the translation of PIA findings into further policy development. PIA-specific reporting guidelines would help in this regard. The modest level of translation efforts is another pointer to the “deliberation to policy gap”. The results of this review could inform the design of new PIAs and future efforts to improve PIA comparability and outcome translation. 相似文献999.
Dietmar Reusch Markus Haberger Tobias Kailich Anna-Katharina Heidenreich Michael Kampe Patrick Bulau Manfred Wuhrer 《MABS-AUSTIN》2014,6(1):185-196
The Fc glycosylation of therapeutic antibodies is crucial for their effector functions and their behavior in pharmacokinetics and pharmacodynamics. To monitor the Fc glycosylation in bioprocess development and characterization, high-throughput techniques for glycosylation analysis are needed. Here, we describe the development of a largely automated high-throughput glycosylation profiling method with multiplexing capillary-gel-electrophoresis (CGE) with laser induced fluorescence (LIF) detection using a DNA analyzer. After PNGaseF digestion, the released glycans were labeled with 9-aminopyrene-1,3,6-trisulfonic acid (APTS) in 96-well plates, which was followed by the simultaneous analysis of up to 48 samples. The peak assignment was conducted by HILIC-UPLC-MS/MS of the APTS-labeled glycans combined with peak fractionation and subsequent CGE-LIF analysis of the MS-characterized fractions. Quantitative data evaluation of the various IgG glycans was performed automatically using an in-house developed software solution. The excellent method accuracy and repeatability of the test system was verified by comparison with two UPLC-based methods for glycan analysis. Finally, the practical value of the developed method was demonstrated by analyzing the antibody glycosylation profiles from fermentation broths after small scale protein A purification. 相似文献
1000.
Nusrat Shahin Qureshi Tobias Matzel Erhan Can Cetiner Robbin Schnieders Hendrik R A Jonker Harald Schwalbe Boris Fürtig 《Nucleic acids research》2021,49(13):7753
The ribosomal S1 protein (rS1) is indispensable for translation initiation in Gram-negative bacteria. rS1 is a multidomain protein that acts as an RNA chaperone and ensures that mRNAs can bind the ribosome in a single-stranded conformation, which could be related to fast recognition. Although many ribosome structures were solved in recent years, a high-resolution structure of a two-domain mRNA-binding competent rS1 construct is not yet available. Here, we present the NMR solution structure of the minimal mRNA-binding fragment of Vibrio Vulnificus rS1 containing the domains D3 and D4. Both domains are homologues and adapt an oligonucleotide-binding fold (OB fold) motif. NMR titration experiments reveal that recognition of miscellaneous mRNAs occurs via a continuous interaction surface to one side of these structurally linked domains. Using a novel paramagnetic relaxation enhancement (PRE) approach and exploring different spin-labeling positions within RNA, we were able to track the location and determine the orientation of the RNA in the rS1–D34 bound form. Our investigations show that paramagnetically labeled RNAs, spiked into unmodified RNA, can be used as a molecular ruler to provide structural information on protein-RNA complexes. The dynamic interaction occurs on a defined binding groove spanning both domains with identical β2-β3-β5 interfaces. Evidently, the 3′-ends of the cis-acting RNAs are positioned in the direction of the N-terminus of the rS1 protein, thus towards the 30S binding site and adopt a conformation required for translation initiation. 相似文献