32 research outputs found
Formal [3 + 2] Reaction of α,α-Diaryl Allylic Alcohols with <i>sec</i>-Alcohols: Proceeding with Sequential Radical Addition/Migration toward 2,3-Dihydrofurans Bearing Quaternary Carbon Centers
An unprecedented
TBHP-promoted formal [3 + 2] annulation of <i>sec</i>-alcohols
with α,α-diaryl allylic alcohols
has been developed, leading to 2,3-dihydrofurans in moderate to excellent
yields with good functional group tolerance. This procedure involves
sequential radical addition, 1,2-aryl migration, and a dehydration
process, where the migration of aryl with lower electron density is
favored. Notably, cyclic reactions with <i>sec</i>-alcohols
also ran smoothly, providing a novel method to access oxaspiro compounds
Image_1_The Vacuolar Protein Sorting-38 Subunit of the Arabidopsis Phosphatidylinositol-3-Kinase Complex Plays Critical Roles in Autophagy, Endosome Sorting, and Gravitropism.pdf
<p>The family of phosphatidylinositols (PtdIns) plays essential roles in membrane identity and intracellular trafficking events. In animals and yeast, PtdIn-3-phosphate, which is particularly important for endosomal sorting, lysosomal/vacuolar transport and autophagy, is assembled by two conserved kinase complexes comprised of the catalytic VACUOLAR PROTEIN SORTING (VPS)-34 subunit, along with VPS15, AUTOPHAGY-RELATED (ATG)-6, and either ATG14 (complex I) or VPS38 (complex II). Here, we describe the Arabidopsis ortholog of VPS38 and show by interaction assays that it assembles into a tetrameric PtdIn-3 kinase complex II. Plants missing VPS38 are viable but have dampened pollen germination and heightened seed abortion, and display a dwarf rosette phenotype, with defects in leaf and vascular development and sucrose sensing. vps38 seeds accumulate irregular protein storage vesicles and suppress processing of storage proteins into their mature forms. Consistent with a role for PtdIn-3-phosphate in autophagy, vps38 mutants are hypersensitive to nitrogen and fixed-carbon starvation and show reduced autophagic transport of cargo into vacuoles. vps38 seedlings also have dampened root gravitropism, which is underpinned by aberrant vectoral auxin transport likely caused by defects in plasma membrane/endosome cycling of the PIN-FORMED family of auxin transporters necessary for asymmetric cell elongation. Collectively, this study places VPS38 and its class-III PtdIn-3 kinase complex at the nexus of numerous endosomal trafficking events important to plant growth and development.</p
MicroRNA-221 Mediates the Effects of PDGF-BB on Migration, Proliferation, and the Epithelial-Mesenchymal Transition in Pancreatic Cancer Cells
<div><p>The platelet-derived growth factor (PDGF) signaling pathway has been found to play important roles in the development and progression of human cancers by regulating the processes of cell proliferation, apoptosis, migration, invasion, metastasis, and the acquisition of the epithelial-mesenchymal transition (EMT) phenotype. Moreover, PDGF signaling has also been found to alter the expression profile of miRNAs, leading to the reversal of EMT phenotype. Although the role of miRNAs in cancer has been documented, there are very few studies documenting the cellular consequences of targeted re-expression of specific miRNAs. Therefore, we investigated whether the treatment of human pancreatic cancer cells with PDGF could alter the expression profile of miRNAs, and we also assessed the cellular consequences. Our study demonstrates that miR-221 is essential for the PDGF-mediated EMT phenotype, migration, and growth of pancreatic cancer cells. Down-regulation of TRPS1 by miR-221 is critical for PDGF-mediated acquisition of the EMT phenotype. Additionally, the PDGF-dependent increase in cell proliferation appears to be mediated by inhibition of a specific target of miR-221 and down-regulation of p27Kip1.</p></div
miR-221 is regulated by the PDGF-BB signaling pathway.
<p>A: The relative miRNA levels in AsPC-1 cells treated with vehicle or PDGF-BB (20 ng/ml, 24 hr) B, C: Time-course expression of the relative expression of miR-221-3p, miR-221-5p, miR-222-3p and miR-222-5p (B), and miR-221 transcripts (Pri-miR-221), Pre-miR-221 or mature miR-221 (C) normalized to GAPDH (for Pri-miR-221 or Pre-miR-221), or U6 small nuclear RNA (for miR-221-3p, miR-221-5p, miR-222-3p, miR-222-5p and mature miR-221) in AsPC-1 cells treated with vehicle or PDGF-BB (20 ng/ml, 24 hr). D: AsPC-1 cells were treated with vehicle or PDGF-BB (20 ng/ml), or transfected with a negative control, the miR-221 mimic, anti-mIR-221, or anti-mIR-221 and followed by PDGF-BB treatment., and subjected to qRT-PCR of miR221. All of the treatments in this figure were carried out in triplicate, and the results are displayed as the means ± SD.</p
Exploration of genetic diversity among medicinally important genus <i>Epimedium</i> species based on genomic and EST-SSR marker
<div><p><i>Epimedium</i> species has gained prime importance due to their medicinal and economic values. Therefore, in this study, 26 genomic SSR and 10 EST-SSR markers were developed for 13 medicinal species of the <i>Epimedium</i> genus and one out-group species <i>Vancouveria hexandra</i> W. J. Hooker to explore the existing genetic diversity. A total of 100 alleles by genomic SSR and 65 by EST-SSR were detected. The genomic SSR markers were presented between 2–7 alleles per locus. The observed heterozygosity (<i>H</i><sub>o</sub>) and expected heterozygosity (<i>H</i><sub>e</sub>) ranged from 0.00 to 4.5 and 0.0254 to 2.8108, respectively. Similarly, for EST-SSR, these values were ranged from 3.00 to 4.00 and 1.9650 to 2.7142. The number of alleles for EST-SSR markers ranged from 3 to 10 with an average of 3.51 per loci. It has been concluded that medicinally important species of the genus <i>Epimedium</i> possesses lower intraspecific genetic variation.</p></div
miR-221 is critical for the PDGF-mediated epithelial-mesenchymal transition phenotype, migration, and growth of AsPC-1 cells.
<p>AsPC-1 cells were transfected with a negative control, the miR-221 mimic, or antisense oligonucleotides to miR-221 (anti-mIR-221). The cells were then treated with PDGF-BB (20 ng/ml) for 24 h and subjected to qRT-PCR (A, C) or Western blot analysis (B) of the transcription factors and EMT-specific gene markers. AsPC-1 cells were transfected with a negative control, the miR-221 mimic, or antisense oligonucleotides to miR-221 (anti-mIR-221) and subjected to the Matrigel transmembrane invasion assay (D) in the presence or absence of 20 ng/ml PDGF-BB. AsPC-1 cells were transfected with a negative control, the miR-221 mimic, or antisense oligonucleotides to miR-221 (anti-mIR-221), followed by PDGF-BB treatment for 24 h, and then were stained with a FITC-conjugated antibody against the proliferation marker PCNA and DAPI. In total, 150 cells were counted per condition, and the percentage of PCNA-positive cells (E) is presented. All treatment experiments in this figure were carried out in triplicate, and the results are displayed as the means ± SD.</p
PDGF mediated the EMT by miR-221 targeting TRPS1.
<p>AsPC-1 cells were transfected with a negative control mimic, the miR-221 mimic, antisense oligonucleotides to miR-221 (anti-mIR-221) or TRPS1 siRNA. The cells were then treated with PDGF-BB (20 ng/ml) for 24 h and subjected to qRT-PCR of TRPS1. AsPC-1 cells were transfected with a negative control mimic, the miR-221 mimic, antisense oligonucleotides to miR-221 (anti-mIR-221) or TRPS1 siRNA for 3 days and subjected to Western blot analysis of TRPS1, ZEB2, E-cadherin and vimentin. AsPC-1 cells were transfected with antisense oligonucleotides to miR-221 (anti-mIR-221). The cells were then treated with a negative control or miR-221 mimic for 3 days and subjected to qRT-PCR for ZEB2 (C), E-cadherin (D) and vimentin (E). AsPC-1 cells were transfected with a negative control mimic, the miR-221 mimic or antisense oligonucleotides to miR-221 (anti-mIR-221). The cells were then treated with PDGF-BB (20 ng/ml) for 24 h and subjected to immunofluorescence staining for vimentin (F) and E-cadherin (G) All treatments in this figure were carried out in triplicate, and the results are displayed as the means ± SD.</p
Table8.DOCX
<p>The soybean cyst nematode (SCN), Heterodera glycines Ichinohe (Phylum Nematoda), is a major pathogen of soybean. It causes substantial yield losses worldwide and is difficult to control because the cyst protects the eggs which can remain viable for nearly a decade. Crop rotation with non-host crops and use of biocontrol organisms such as fungi and bacteria offer promising approaches, but remain hampered by lack of knowledge of the biology of nematode parasitic organisms. We used a high-throughput metabarcoding approach to characterize fungal communities associated with the SCN cyst, a microenvironment in soil that may harbor both nematode parasites and plant pathogens. SCN cysts were collected from a long-term crop rotation experiment in Southeastern Minnesota at three time points over two growing seasons to characterize diversity of fungi inhabiting cysts and to examine how crop rotation and seasonal variation affects fungal communities. A majority of fungi in cysts belonged to Ascomycota and Basidiomycota, but the presence of several early diverging fungal subphyla thought to be primarily plant and litter associated, including Mortierellomycotina and Glomeromycotina (e.g., arbuscular mycorrhizal fungi), suggests a possible role as nematode egg parasites. Species richness varied by both crop rotation and season and was higher in early years of crop rotation and in fall at the end of the growing season. Crop rotation and season also impacted fungal community composition and identified several classes of fungi, including Eurotiomycetes, Sordariomycetes, and Orbiliomycetes (e.g., nematode trapping fungi), with higher relative abundance in early soybean rotations. The relative abundance of several genera was correlated with increasing years of soybean. Fungal communities also varied by season and were most divergent at midseason. The percentage of OTUs assigned to Mortierellomycotina_cls_Incertae_sedis and Sordariomycetes increased at midseason, while Orbiliomycetes decreased at midseason, and Glomeromycetes increased in fall. Ecological guilds of fungi containing an animal-pathogen lifestyle, as well as potential egg-parasitic taxa previously isolated from parasitized SCN eggs, increased at midseason. The animal pathogen guilds included known (e.g., Pochonia chlamydosporia) and new candidate biocontrol organisms. This research advances knowledge of the ecology of nematophagous fungi in agroecosystems and their use as biocontrol agents of the SCN.</p
Table9.DOCX
<p>The soybean cyst nematode (SCN), Heterodera glycines Ichinohe (Phylum Nematoda), is a major pathogen of soybean. It causes substantial yield losses worldwide and is difficult to control because the cyst protects the eggs which can remain viable for nearly a decade. Crop rotation with non-host crops and use of biocontrol organisms such as fungi and bacteria offer promising approaches, but remain hampered by lack of knowledge of the biology of nematode parasitic organisms. We used a high-throughput metabarcoding approach to characterize fungal communities associated with the SCN cyst, a microenvironment in soil that may harbor both nematode parasites and plant pathogens. SCN cysts were collected from a long-term crop rotation experiment in Southeastern Minnesota at three time points over two growing seasons to characterize diversity of fungi inhabiting cysts and to examine how crop rotation and seasonal variation affects fungal communities. A majority of fungi in cysts belonged to Ascomycota and Basidiomycota, but the presence of several early diverging fungal subphyla thought to be primarily plant and litter associated, including Mortierellomycotina and Glomeromycotina (e.g., arbuscular mycorrhizal fungi), suggests a possible role as nematode egg parasites. Species richness varied by both crop rotation and season and was higher in early years of crop rotation and in fall at the end of the growing season. Crop rotation and season also impacted fungal community composition and identified several classes of fungi, including Eurotiomycetes, Sordariomycetes, and Orbiliomycetes (e.g., nematode trapping fungi), with higher relative abundance in early soybean rotations. The relative abundance of several genera was correlated with increasing years of soybean. Fungal communities also varied by season and were most divergent at midseason. The percentage of OTUs assigned to Mortierellomycotina_cls_Incertae_sedis and Sordariomycetes increased at midseason, while Orbiliomycetes decreased at midseason, and Glomeromycetes increased in fall. Ecological guilds of fungi containing an animal-pathogen lifestyle, as well as potential egg-parasitic taxa previously isolated from parasitized SCN eggs, increased at midseason. The animal pathogen guilds included known (e.g., Pochonia chlamydosporia) and new candidate biocontrol organisms. This research advances knowledge of the ecology of nematophagous fungi in agroecosystems and their use as biocontrol agents of the SCN.</p
PDGF-mediated inhibition of p27Kip1 by miR-221 Promotes Cell proliferation.
<p>(A, B): AsPC-1 cells were transfected with a negative control mimic, the miR-221 mimic, antisense oligonucleotides to miR-221 (anti-mIR-221) or p27Kip1 siRNA. The cells were then treated with PDGF-BB (20 ng/ml) for 24 h and subjected to qRT-PCR (A) and Western blot analysis (B) for p27Kip1. (C): AsPC-1 cells were transfected with negative control or p27Kip1 siRNA and subjected to the MTT cell proliferation assay (The results are indicated as the absorbance readings at 490 nm). (C) (D, E): AsPC-1 cells were transfected with a negative control mimic, the miR-221 mimic, antisense oligonucleotides to miR-221 (anti-mIR-221) or p27Kip1 siRNA. The cells were then treated with PDGF-BB (20 ng/ml) for 24 h and subjected to staining with a FITC-conjugated antibody against the proliferation marker PCNA and DAPI (E). In total, 150 cells were counted per condition, and the percentage of PCNA-positive cells is presented (D). All experiments in this figure were carried out in triplicate, and the results are displayed as the means ± SD.</p