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21.
Coregulation of vascular tube stabilization by endothelial cell TIMP-2 and pericyte TIMP-3 下载免费PDF全文
Saunders WB Bohnsack BL Faske JB Anthis NJ Bayless KJ Hirschi KK Davis GE 《The Journal of cell biology》2006,175(1):179-191
The endothelial cell (EC)-derived tissue inhibitor of metalloproteinase-2 (TIMP-2) and pericyte-derived TIMP-3 are shown to coregulate human capillary tube stabilization following EC-pericyte interactions through a combined ability to block EC tube morphogenesis and regression in three-dimensional collagen matrices. EC-pericyte interactions strongly induce TIMP-3 expression by pericytes, whereas ECs produce TIMP-2 in EC-pericyte cocultures. Using small interfering RNA technology, the suppression of EC TIMP-2 and pericyte TIMP-3 expression leads to capillary tube regression in these cocultures in a matrix metalloproteinase-1 (MMP-1)-, MMP-10-, and ADAM-15 (a disintegrin and metalloproteinase-15)-dependent manner. Furthermore, we show that EC tube morphogenesis (lumen formation and invasion) is primarily controlled by the TIMP-2 and -3 target membrane type (MT) 1 MMP. Additional targets of these inhibitors include MT2-MMP and ADAM-15, which also regulate EC invasion. Mutagenesis experiments reveal that TIMP-3 requires its proteinase inhibitory function to induce tube stabilization. Overall, these data reveal a novel role for both TIMP-2 and -3 in the pericyte-induced stabilization of newly formed vascular networks that are predisposed to undergo regression and reveal specific molecular targets of the inhibitors regulating these events. 相似文献
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The large N-linked oligosaccharides released from Schizosaccharomyces pombe
by endo-beta-N-acetylglucosaminidase H were examined to determine how the
negatively chargedpyruvylated galactoses present (Gemmill,T.R., and
Trimble,R.B., 1996, J. Biol. Chem ., 271, 25945-25949) were attached to the
oligosaccharide chains. Binding of biotinylated human serum amyloid P and
peanut agglutinin to native and depyruvylated S.pombe glycoproteins,
respectively, indicated that the pyruvylated epitope was likely to be in
the beta configuration. Examination by high- field 1H NMR of whole glycans
and a disaccharide fragment released from them on partial acid hydrolysis
showed that the pyruvylated galactose species was in fact beta1,3-linked to
a second galactose, and this occurred an average of five to six times on
nominal Gal57Man64GlcNAc N- glycans. The pyruvate-2,(4,6)Gal-beta1,3Gal
epitope is chemically similar to acetaldehyde-Galbeta1,3Gal groups found on
the glycoproteins from Paramyxovirus-infected bovine kidney cells (Prehm,
P., Scheid,A. and Choppin,P.W. ,1979, J. Biol. Chem ., 254, 9669-9677). The
1:1 stoichiometry between pyruvate and beta-linked galactose in these
S.pombe glycans indicates that either pyruvate addition to terminal
beta1,3Gal is highly efficient or that pyruvylated Gal is transferred en
bloc to alpha1,2-linked Gal residues in theN-linked chains. In
contradiction to many galactomannan-producing fungi, which add substantial
amounts of Gal in the furanose form to their glycoproteins, all detectable
Gal in the large S.pombe galactomannans is in the pyranose form, as found
in higher eukaryotes. The current work shows that the S.pombe outer chain
structure is a poly-alpha1,6Man backbone 2- O-substituted with either Gal
or the pyruvylated galactobiose and contains little alpha1,2-linked or
2-O-substituted Man. This is in contrast to the S. cerevisiae outer chain,
which is poly-alpha1,6Man substituted with alpha1,2-linked Man sidechains
(Ballou,C.E. ,1990, Methods Enzymol , 185, 440-470).
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Abamectin is nematicidal to Meloidogyne incognita and Rotylenchulus reniformis, but the duration and length of cotton taproot protection from nematode infection by abamectin-treated seed is unknown. Based on the position of initial root-gall formation along the developing taproot from 21 to 35 d after planting, infection by M. incognita was reduced by abamectin seed treatment. Penetration of developing taproots by both nematode species was suppressed at taproot length of 5 cm by abamectin-treated seed, but root penetration increased rapidly with taproot development. Based on an assay of nematode mobility to measure abamectin toxicity, the mortality of M. incognita associated with a 2-d-old emerging cotton radicle was lower than mortality associated with the seed coat, indicating that more abamectin was on the seed coat than on the radicle. Thus, the limited protection of early stage root development suggested that only a small portion of abamectin applied to the seed was transferred to the developing root system. 相似文献
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Brandon M. Lind Mitra Menon Constance E. Bolte Trevor M. Faske Andrew J. Eckert 《Tree Genetics & Genomes》2018,14(2):29
There is substantial interest in uncovering the genetic basis of the traits underlying adaptive responses in tree species, as this information will ultimately aid conservation and industrial endeavors across populations, generations, and environments. Fundamentally, the characterization of such genetic bases is within the context of a genetic architecture, which describes the mutlidimensional relationship between genotype and phenotype through the identification of causative variants, their relative location within a genome, expression, pleiotropic effect, environmental influence, and degree of dominance, epistasis, and additivity. Here, we review theory related to polygenic local adaptation and contextualize these expectations with methods often used to uncover the genetic basis of traits important to tree conservation and industry. A broad literature survey suggests that most tree traits generally exhibit considerable heritability, that underlying quantitative genetic variation (QST) is structured more so across populations than neutral expectations (FST) in 69% of comparisons across the literature, and that single-locus associations often exhibit small estimated per-locus effects. Together, these results suggest differential selection across populations often acts on tree phenotypes underlain by polygenic architectures consisting of numerous small to moderate effect loci. Using this synthesis, we highlight the limits of using solely single-locus approaches to describe underlying genetic architectures and close by addressing hurdles and promising alternatives towards such goals, remark upon the current state of tree genomics, and identify future directions for this field. Importantly, we argue, the success of future endeavors should not be predicated on the shortcomings of past studies and will instead be dependent upon the application of theory to empiricism, standardized reporting, centralized open-access databases, and continual input and review of the community’s research. 相似文献
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Intra-specific heterogeneity of the rDNA internal transcribed spacer in the Simulium damnosum (Diptera: Simuliidae) complex 总被引:3,自引:0,他引:3
The internal transcribed spacer (ITS) of the rRNA gene cluster has been
used as a model for the study of the action of concerted evolution and
molecular drive on repeated sequence families. In contrast to this general
finding, preliminary DNA sequence analysis of cloned representatives of the
ITS from the West African black fly species complex Simulium damnosum s.1.
demonstrated extensive intra-individual and intra-specific polymorphisms.
Variability in the ITS was primarily confined to the ITS1 domain. The
degree and type of intra-individual and intra-specific variability within
the ITS was further characterized using gel electrophoresis, DNA
hybridization, and heteroduplex analysis of the PCR products generated from
the ITS1 domain. ITS1 copies from individual S. damnosum s.1. differed in
length and sequence composition. These results, when taken together,
demonstrate that a large degree of intra-individual and intra-specific
heterogeneity exists in the ITS of S. damnosum s.1. The intra-individual
heterogeneity was greater in the savanna-dwelling than forest-dwelling
sibling species of S. damnosum s.1. This heterogeneity may be due in part
to inter-breeding among sympatric sibling species, coupled with disturbance
of S. damnosum s.1. populations resulting from intensive vector control
efforts.
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30.
Deepa Indira Shankara Narayanan Varadarajan Santhik Subhasingh Lupitha Asha Lekshmi Krupa Ann Mathew Aneesh Chandrasekharan Prakash Rajappan Pillai Ishaque Pulikkal Kadamberi Indu Ramachandran Hari Sekar Anurup Kochucherukkan Gopalakrishnan Santhoshkumar TR 《European journal of cell biology》2018,97(1):1-14
The selective autophagic removal of mitochondria called mitophagy is an essential physiological signaling for clearing damaged mitochondria and thus maintains the functional integrity of mitochondria and cells. Defective mitophagy is implicated in several diseases, placing mitophagy as a target for drug development. The identification of key regulators of mitophagy as well as chemical modulators of mitophagy requires sensitive and reliable quantitative approaches. Since mitophagy is a rapidly progressing event and sub-microscopic in nature, live cell image-based detection tools with high spatial and temporal resolution is preferred over end-stage assays. We describe two approaches for measuring mitophagy in mammalian cells using stable cells expressing EGFP-LC3 – Mito-DsRed to mark early phase of mitophagy and Mitochondria-EGFP – LAMP1-RFP stable cells for late events of mitophagy. Both the assays showed good spatial and temporal resolution in wide-field, confocal and super-resolution microscopy with high-throughput adaptable capability. A limited compound screening allowed us to identify a few new mitophagy inducers. Compared to the current mitophagy tools, mito-Keima or mito-QC, the assay described here determines the direct delivery of mitochondrial components to the lysosome in real time mode with accurate quantification if monoclonal cells expressing a homogenous level of both probes are established. Since the assay described here employs real-time imaging approach in a high-throughput mode, the platform can be used both for siRNA screening or compound screening to identify key regulators of mitophagy at decisive stages. 相似文献