The Experts below are selected from a list of 66 Experts worldwide ranked by ideXlab platform
Shigetoshi Antoku - One of the best experts on this subject based on the ideXlab platform.
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enhancement of x Ray Cell killing in cultured mammalian Cells by the protein phosphatase inhibitor calyculin a
Cancer Research, 1994Co-Authors: Katsumasa Nakamura, Shigetoshi AntokuAbstract:Effects of calyculin A, a potent inhibitor of protein phosphatases 1 and 2A, on X-Ray Cell killing and chromatin structure were studied using cultured mammalian Cells (BHK21). Calyculin A at concentrations of 2.5–20 nm enhanced X-Ray Cell killing when exponentially growing BHK21 Cells were treated with calyculin A for 30 min after X-irradiation. A 30-min treatment with this drug induced chromatin condensation transiently. These results suggest that the enhancement of X-Ray Cell killing by calyculin A is caused by the events associated with chromatin condensation. Protein phosphatase-targeting drugs may represent a new class of radiation sensitizers.
Bdeir Roba - One of the best experts on this subject based on the ideXlab platform.
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Gene dosage effects and signatures of purifying selection in lateral organ boundaries domain (LBD) genes LBD1 and LBD18
'Springer Science and Business Media LLC', 2016Co-Authors: Bdeir Roba, Busov Victor, Yordanov Yordan, Gailing OliverAbstract:© 2016, Springer-Verlag Wien. Wood formation is an economically and environmentally important process and has played a significant role in the evolution of terrestrial plants. Despite its significance, the molecular underpinnings of the process are still poorly understood. We have previously shown that four lateral organ boundaries (LBD) transcription factors have important roles in the regulation of secondary (woody) growth with two (LBD1 and LBD4) involved in secondary phloem and Ray Cell development and two (LBD15 and LBD18) in secondary xylem formation. We studied gene copy number and variation in DNA and amino acid sequences of the four LBDs in a wide range of woody and herbaceous plant taxa with fully sequenced and annotated genomes. LBD1 showed the highest gene copy number across species, and gene copy number was strongly and significantly correlated with tangential Ray width. The climbing vines, cucumber and grape, with wide multiseriate Rays (\u3e 10 Cells wide) showed the highest gene copy number. Because the growth habit of woody lianas like grape requires significant twisting and bending, it was suggested that the unlignified Ray parenchyma Cells likely facilitate stem flexibility and maintenance of xylem conductivity. We further demonstrate conservation of amino acids in LBD18 protein sequences specific to woody taxa downstream of the LBD domain. Neutrality tests showed evidence for strong purifying selection on these regions across various orders, indicating important functional roles in woody taxa. Additionally, structural modeling demonstrates that these regions have a significant impact on tertiary protein structure and thus are likely of significant functional importance
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PHYLOGENETIC ANALYSES, GENE DOSAGE EFFECT AND SELECTION IN MEMBERS OF THE LATERAL BOUNDARY DOMAIN (LBD) GENES TRANSCRIPTION FACTOR FAMILY
Digital Commons @ Michigan Tech, 2015Co-Authors: Bdeir RobaAbstract:Wood formation is an economically and environmentally important process and has played a significant role in the evolution of terrestrial plants. Despite its significance, the molecular underpinnings of the process are still poorly understood. We have previously shown that four Lateral Boundary Domain (LBD) transcription factors have important roles in the regulation of wood formation with two (LBD1 and LBD4) involved in secondary phloem and Ray Cell development and two (LBD15 and LBD18) in secondary xylem formation. Here, we used comparative phylogenetic analyses to test potential roles of the four LBD genes in the evolution of woodiness. We studied the copy number and variation in DNA and amino acid sequences of the four LBDs in a wide range of woody and herbaceous plant taxa with fully sequenced and annotated genomes. LBD1 showed the highest gene copy number across the studied species, and LBD1 gene copy number was strongly and significantly correlated with the level of Ray seriation. The lianas, cucumber and grape, with multiseriate Ray Cells showed the highest gene copy number (12 and 11, respectively). Because lianas’ growth habit requires significant twisting and bending, the less lignified Ray parenchyma Cells likely facilitate stem flexibility and maintenance of xylem conductivity. We further demonstrate conservation of amino acids in the LBD18 protein sequences that are specific to woody taxa. Neutrality tests showed evidence for strong purifying selection on these gene regions across various orders, indicating adaptive convergent evolution of LBD18. Structural modeling demonstrates that the conserved amino acids have a significant impact on the tertiary protein structure and thus are likely of significant functional importance
Katsumasa Nakamura - One of the best experts on this subject based on the ideXlab platform.
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enhancement of x Ray Cell killing in cultured mammalian Cells by the protein phosphatase inhibitor calyculin a
Cancer Research, 1994Co-Authors: Katsumasa Nakamura, Shigetoshi AntokuAbstract:Effects of calyculin A, a potent inhibitor of protein phosphatases 1 and 2A, on X-Ray Cell killing and chromatin structure were studied using cultured mammalian Cells (BHK21). Calyculin A at concentrations of 2.5–20 nm enhanced X-Ray Cell killing when exponentially growing BHK21 Cells were treated with calyculin A for 30 min after X-irradiation. A 30-min treatment with this drug induced chromatin condensation transiently. These results suggest that the enhancement of X-Ray Cell killing by calyculin A is caused by the events associated with chromatin condensation. Protein phosphatase-targeting drugs may represent a new class of radiation sensitizers.
Scott W Emmons - One of the best experts on this subject based on the ideXlab platform.
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axial patterning of c elegans male sensilla identities by selector genes
Developmental Biology, 2004Co-Authors: Robyn Lints, L Jia, Kyuhyung Kim, Scott W EmmonsAbstract:The fan and Rays of the C. elegans male tail constitute a compound sensory organ essential for mating. Within this organ, the individual sensilla, known as Rays, have unique identities. We show that Ray identities are patterned by a selector gene mechanism in a manner similar to other serially homologous axial structures. One selector gene that promotes the identities of a subset of the Rays is the Hox gene egl-5. Within EGL-5-expressing Rays, further patterning is provided by a Pax-6 homolog and a signal of the TGFβ family. These genes and pathway coordinately specify multiple Ray properties affecting all three terminal Ray Cell types. These properties include complex patterns of FMRFamide-like (FaRP) neuropeptides, serotonin (5HT) and dopamine expression, and Ray morphology. Differences in these differentiated characteristics give each sensillum a unique identity and potentially endow the compound Ray organ with a higher-order information gathering capacity.
Muhammad Iqbal - One of the best experts on this subject based on the ideXlab platform.
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structure of the vascular cambium of varying age and its derivative tissues in the stem of ficus rumphii blume
Botanical Journal of the Linnean Society, 1992Co-Authors: Sagheer Ajmal, Muhammad IqbalAbstract:AJMAL, S. & IQBAL, M., 1992. Structure of the vascular cambium of varying age and its derivative tissues in the stem of Ficus rumphii Blume. The cambial Cells of Ficus rumphii and their derivatives vary in size and number with the age of the tree. The fusiform initials, vessel elements, sieve-tube members, xylem fibres and phloem fibres are relatively short in the terminal part of the stem axis, consistently longer down the stem reaching a maximum, and short again in the main trunk. The width of the respective Cells shows a similar variation. The Ray Cell initials increase both in number and size, and form Rays of varying dimensions. Uniseriate and biseriate cambial Rays are abundant, while multiseriate Rays are especially sparse in the young shoot. The proportion of uni- and biseriate Rays falls in the lower part of the stem whereas that of multiseriate Rays increases. Likewise, short cambial Rays are abundant in young branches but their frequency decreases in the trunk region, leading to a rise of the tall Ray population. The Rays in the phloem and xylem regions reflect a similar variation pattern with certain fluctuations. The overall proportion of the Rays increases in the older part of the axis, reaching a maximum tangential area in the trunk. The transectional area of vessel elements remains more or less constant down to the base after an initial increase in the terminal region, while the sieve-tube proportion tends to be constant in the basal region after a consistent gain from the tree top basewards.
