78 research outputs found
Homeobox Transcription Factors Are Required for Conidiation and Appressorium Development in the Rice Blast Fungus Magnaporthe oryzae
The appropriate development of conidia and appressoria is critical in the disease cycle of many fungal pathogens, including Magnaporthe oryzae. A total of eight genes (MoHOX1 to MoHOX8) encoding putative homeobox transcription factors (TFs) were identified from the M. oryzae genome. Knockout mutants for each MoHOX gene were obtained via homology-dependent gene replacement. Two mutants, ÎMohox3 and ÎMohox5, exhibited no difference to wild-type in growth, conidiation, conidium size, conidial germination, appressorium formation, and pathogenicity. However, the ÎMohox1 showed a dramatic reduction in hyphal growth and increase in melanin pigmentation, compared to those in wild-type. ÎMohox4 and ÎMohox6 showed significantly reduced conidium size and hyphal growth, respectively. ÎMohox8 formed normal appressoria, but failed in pathogenicity, probably due to defects in the development of penetration peg and invasive growth. It is most notable that asexual reproduction was completely abolished in ÎMohox2, in which no conidia formed. ÎMohox2 was still pathogenic through hypha-driven appressoria in a manner similar to that of the wild-type. However, ÎMohox7 was unable to form appressoria either on conidial germ tubes, or at hyphal tips, being non-pathogenic. These factors indicate that M. oryzae is able to cause foliar disease via hyphal appressorium-mediated penetration, and MoHOX7 is mutually required to drive appressorium formation from hyphae and germ tubes. Transcriptional analyses suggest that the functioning of M. oryzae homeobox TFs is mediated through the regulation of gene expression and is affected by cAMP and Ca2+ signaling and/or MAPK pathways. The divergent roles of this gene set may help reveal how the genome and regulatory pathways evolved within the rice blast pathogen and close relatives
Speciation analysis of iodine and bromine at picogram-per-gram levels in polar ice
Iodine and bromine species participate in key atmospheric reactions including the formation of cloud con- densation nuclei and ozone depletion. We present a novel method coupling a high-performance liquid chromatogra- phy with ion chromatography and inductively coupled plas- ma mass spectrometry, which allows the determination of iodine (I) and bromine (Br) species (IO3â, Iâ, Brâ, BrO3â) at the picogram-per-gram levels presents in Antarctic ice. Chromatographic separation was achieved using an ION- PACÂź AS16 Analytical Column with NaOH as eluent. Detection limits for I and Br species were 5 to 9 pg gâ1 with an uncertainty of less than 2.5% for all considered species. Inorganic iodine and bromine species have been determined in Antarctic ice core samples, with concentrations close to the detection limits for iodine species, and approximately 150 pg gâ1 for Brâ. Although iodate (IO3â) is the most abundant iodine species in the atmosphere, only the much rarer iodide (Iâ) species was present in Antarctic Holocene ice. Bromine was found to be present in Antarctic ice as Brâ
International Consensus Statement on Rhinology and Allergy: Rhinosinusitis
Background: The 5 years since the publication of the first International Consensus Statement on Allergy and Rhinology: Rhinosinusitis (ICARâRS) has witnessed foundational progress in our understanding and treatment of rhinologic disease. These advances are reflected within the more than 40 new topics covered within the ICARâRSâ2021 as well as updates to the original 140 topics. This executive summary consolidates the evidenceâbased findings of the document. Methods: ICARâRS presents over 180 topics in the forms of evidenceâbased reviews with recommendations (EBRRs), evidenceâbased reviews, and literature reviews. The highest grade structured recommendations of the EBRR sections are summarized in this executive summary. Results: ICARâRSâ2021 covers 22 topics regarding the medical management of RS, which are grade A/B and are presented in the executive summary. Additionally, 4 topics regarding the surgical management of RS are grade A/B and are presented in the executive summary. Finally, a comprehensive evidenceâbased management algorithm is provided. Conclusion: This ICARâRSâ2021 executive summary provides a compilation of the evidenceâbased recommendations for medical and surgical treatment of the most common forms of RS
2-N-Benzyl-2,6-dide-oxy-2,6-imino-3,4-O-iso-propyl-idene-d-allono-nitrile.
X-ray crystallography firmly established the relative stereochemistry of the title compound, C16H20N2O3. The acetonide ring adopts an envelope conformation with one of the O atoms as the flap and the piperidine ring adopts a slightly twisted boat conformation. The absolute configuration was determined by use of d-ribose as the starting material. The compound exists as O-HâŻO hydrogen-bonded chains of mol-ecules running parallel to the b axis
Maturation of resting spores of Plasmodiophora brassicae continues after host cell death
Iteamine, the first alkaloid isolated from Itea virginica L. inflorescence.
Iteamine, o-aminobenzyl ÎČ-D-glucopyranoside, is the first alkaloid to be isolated from Itea virginica. Itea is the sole plant source of D-psicose, a rare sugar likely to be a major dietary supplement. The structure of iteamine was established by NMR and confirmed by total synthesis. Iteamine and its galacto-analog (which was not found in Itea plants) showed no strong inhibition of any of the 15 glycosidases tested; unnatural galacto-iteamine was a weak inhibitor of chicken liver α-N-acetylgalactosaminidase
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