The Experts below are selected from a list of 210 Experts worldwide ranked by ideXlab platform
Christoph Dehio - One of the best experts on this subject based on the ideXlab platform.
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conjugative DNA Transfer into human cells by the virb vird4 type iv secretion system of the bacterial pathogen bartonella henselae
Proceedings of the National Academy of Sciences of the United States of America, 2011Co-Authors: Gunnar Schroder, Ralf Schuelein, Maxime Quebatte, Christoph DehioAbstract:Bacterial type IV secretion systems (T4SS) mediate interbacterial conjugative DNA Transfer and transkingdom protein Transfer into eukaryotic host cells in bacterial pathogenesis. The sole bacterium known to naturally Transfer DNA into eukaryotic host cells via a T4SS is the plant pathogen Agrobacterium tumefaciens. Here we demonstrate T4SS-mediated DNA Transfer from a human bacterial pathogen into human cells. We show that the zoonotic pathogen Bartonella henselae can Transfer a cryptic plasmid occurring in the bartonellae into the human endothelial cell line EA.hy926 via its T4SS VirB/VirD4. DNA Transfer into EA.hy926 cells was demonstrated by using a reporter derivative of this Bartonella-specific mobilizable plasmid generated by insertion of a eukaryotic egfp-expression cassette. Fusion of the C-terminal secretion signal of the endogenous VirB/VirD4 protein substrate BepD with the plasmid-encoded DNA-transport protein Mob resulted in a 100-fold increased DNA Transfer rate. Expression of the delivered egfp gene in EA.hy926 cells required cell division, suggesting that nuclear envelope breakdown may facilitate passive entry of the Transferred ssDNA into the nucleus as prerequisite for complementary strand synthesis and transcription of the egfp gene. Addition of an eukaryotic neomycin phosphoTransferase expression cassette to the reporter plasmid facilitated selection of stable transgenic EA.hy926 cell lines that display chromosomal integration of the Transferred plasmid DNA. Our data suggest that T4SS-dependent DNA Transfer into host cells may occur naturally during human infection with Bartonella and that these chronically infecting pathogens have potential for the engineering of in vivo gene-delivery vectors with applications in DNA vaccination and therapeutic gene therapy.
Gynheung An - One of the best experts on this subject based on the ideXlab platform.
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OsMLO12, encoding seven transmembrane proteins, is involved with pollen hydration in rice
Plant Reproduction, 2014Co-Authors: Jakyung Yi, Suyoung An, Gynheung AnAbstract:Key message MLO mediates pollen hydration. Abstract Hydration is the first step in pollen germination. However, the process is not well understood. OsMLO12 is highly expressed in mature pollen grains; plants containing alleles caused by Transfer DNA insertions do not produce homozygous progeny. Reciprocal crosses between wild-type and OsMLO12/osmlo12 plants showed that the mutant alleles were not transmitted through the male gametophyte. Microscopic observations revealed that, although mutant grains became mature pollen with three nuclei, they did not germinate in vitro or in vivo due to a failure in hydration. The OsMLO12 protein has seven transmembrane motifs, with an N-terminal extracellular region and a C-terminal cytosolic region. We demonstrated that the C-terminal region mediates a calcium-dependent interaction with calmodulin. Our findings suggest that pollen hydration is regulated by MLO12, possibly through an interaction with calmodulin in the cytosol.
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Binary vectors for efficient transformation of rice
Journal of Plant Biology, 1999Co-Authors: Jong-seong Jeon, Ki-hong Jung, Gynheung AnAbstract:We constructed binary vectors that were designed for Transfer and expression of a gene into rice chromosomes. The binary vectors contained the hygromycin-resistance gene for selection of transformants and multiple-cloning sites within the Transfer DNA. In addition, vectors were designed to express foreign genes using four kinds of promoters. We also report a procedure for efficient transformation of rice plants using scutellum-derived calli and theAgrobacterium strain LBA4404.
Susan F Petricevic - One of the best experts on this subject based on the ideXlab platform.
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the tendency of individuals to Transfer DNA to handled items
Forensic Science International, 2007Co-Authors: Matthew Phipps, Susan F PetricevicAbstract:Abstract This research investigates factors influencing the Transfer of DNA to handled objects and the process known as ‘shedding'. Volunteers were recruited to hold sterile plastic tubes using experiments originally designed by Lowe et al. [A. Lowe, C. Murray, J. Whitaker, G. Tully, P. Gill, The propensity of individuals to deposit DNA and secondary Transfer of low level DNA from individuals to inert surfaces, Forensic Sci. Int. 129 (2002) 25–34]. Transferred cellular material was collected from the tubes and STR profiles generated using the AmpFlSTR SGM Plus™ multiplex with 28 and 34 PCR cycles. Volunteers were asked to hold the tubes with each hand, and to participate in a series of handwashing experiments. The DNA profiling results obtained from the Transferred skin cells were compared. An attempt was made to characterize the volunteers as ‘good' or ‘bad' shedders and to establish which, if any, of the experimental variables were associated with ‘good' shedding. Our results suggest that many factors significantly influence shedding, including which hand an individual touches an item with and the time that has elapsed since they last washed their hands. We have found that it may be more complicated than previously reported to categorise a person as being either a ‘good' or a ‘bad' shedder and that if truly ‘good' shedders exist they may be significantly rarer than some have estimated. In the current research no ‘good' shedders were observed in a group of 60 volunteers. Given these results, it seems that rather than being applied to individual forensic cases, knowledge of shedding characteristics will be most useful in providing general background data for the interpretation of trace DNA evidence.
Gunnar Schroder - One of the best experts on this subject based on the ideXlab platform.
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conjugative DNA Transfer into human cells by the virb vird4 type iv secretion system of the bacterial pathogen bartonella henselae
Proceedings of the National Academy of Sciences of the United States of America, 2011Co-Authors: Gunnar Schroder, Ralf Schuelein, Maxime Quebatte, Christoph DehioAbstract:Bacterial type IV secretion systems (T4SS) mediate interbacterial conjugative DNA Transfer and transkingdom protein Transfer into eukaryotic host cells in bacterial pathogenesis. The sole bacterium known to naturally Transfer DNA into eukaryotic host cells via a T4SS is the plant pathogen Agrobacterium tumefaciens. Here we demonstrate T4SS-mediated DNA Transfer from a human bacterial pathogen into human cells. We show that the zoonotic pathogen Bartonella henselae can Transfer a cryptic plasmid occurring in the bartonellae into the human endothelial cell line EA.hy926 via its T4SS VirB/VirD4. DNA Transfer into EA.hy926 cells was demonstrated by using a reporter derivative of this Bartonella-specific mobilizable plasmid generated by insertion of a eukaryotic egfp-expression cassette. Fusion of the C-terminal secretion signal of the endogenous VirB/VirD4 protein substrate BepD with the plasmid-encoded DNA-transport protein Mob resulted in a 100-fold increased DNA Transfer rate. Expression of the delivered egfp gene in EA.hy926 cells required cell division, suggesting that nuclear envelope breakdown may facilitate passive entry of the Transferred ssDNA into the nucleus as prerequisite for complementary strand synthesis and transcription of the egfp gene. Addition of an eukaryotic neomycin phosphoTransferase expression cassette to the reporter plasmid facilitated selection of stable transgenic EA.hy926 cell lines that display chromosomal integration of the Transferred plasmid DNA. Our data suggest that T4SS-dependent DNA Transfer into host cells may occur naturally during human infection with Bartonella and that these chronically infecting pathogens have potential for the engineering of in vivo gene-delivery vectors with applications in DNA vaccination and therapeutic gene therapy.
Darleen A Demason - One of the best experts on this subject based on the ideXlab platform.
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replication coupled packaging mechanism in positive strand rna viruses synchronized coexpression of functional multigenome rna components of an animal and a plant virus in nicotiana benthamiana cells by agroinfiltration
Journal of Virology, 2008Co-Authors: Padmanaban Annamalai, Fady Rofail, Darleen A DemasonAbstract:Flock house virus (FHV), a bipartite RNA virus of insects and a member of the Nodaviridae family, shares viral replication features with the tripartite brome mosaic virus (BMV), an RNA virus that infects plants and is a member of the Bromoviridae family. In BMV and FHV, genome packaging is coupled to replication, a widely conserved mechanism among positive-strand RNA viruses of diverse origin. To unravel the events that modulate the mechanism of replication-coupled packaging, in this study, we have extended the Transfer DNA (T-DNA)-based agroinfiltration system to express functional genome components of FHV in plant cells (Nicotiana benthamiana). Replication, intracellular membrane localization, and packaging characteristics in agroinfiltrated plant cells revealed that T-DNA plasmids of FHV were biologically active and faithfully mimicked complete replication and packaging behavior similar to that observed for insect cells. Synchronized coexpression of wild-type BMV and FHV genome components in plant cells resulted in the assembly of virions packaging the respective viral progeny RNA. To further elucidate the link between replication and packaging, coat protein (CP) open reading frames were precisely exchanged between BMV RNA 3 (B3) and FHV RNA 2 (F2), creating chimeric RNAs expressing heterologous CP genes (B3/FCP and F2/BCP). Coinfiltration of each chimera with its corresponding genome counterpart to provide viral replicase (B1B2B3/FCP and F1F2/ BCP) resulted in the expected progeny profiles, but virions exhibited a nonspecific packaging phenotype. Complementation with homologous replicase (with respect to CP) failed to enhance packaging specificity. Taken together, we propose that the transcription of CP mRNA from homologous replication and its translation must be synchronized to confer packaging specificity.
