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排序方式: 共有311条查询结果,搜索用时 46 毫秒
91.
Malaika K. Ebert Rebecca E. Spanner Ronnie de Jonge David J. Smith Jason Holthusen Gary A. Secor Bart P. H. J. Thomma Melvin D. Bolton 《Environmental microbiology》2019,21(3):913-927
Perylenequinones are a family of structurally related polyketide fungal toxins with nearly universal toxicity. These photosensitizing compounds absorb light energy which enables them to generate reactive oxygen species that damage host cells. This potent mechanism serves as an effective weapon for plant pathogens in disease or niche establishment. The sugar beet pathogen Cercospora beticola secretes the perylenequinone cercosporin during infection. We have shown recently that the cercosporin toxin biosynthesis (CTB) gene cluster is present in several other phytopathogenic fungi, prompting the search for biosynthetic gene clusters (BGCs) of structurally similar perylenequinones in other fungi. Here, we report the identification of the elsinochrome and phleichrome BGCs of Elsinoë fawcettii and Cladosporium phlei, respectively, based on gene cluster conservation with the CTB and hypocrellin BGCs. Furthermore, we show that previously reported BGCs for elsinochrome and phleichrome are involved in melanin production. Phylogenetic analysis of the corresponding melanin polyketide synthases (PKSs) and alignment of melanin BGCs revealed high conservation between the established and newly identified C. beticola, E. fawcettii and C. phlei melanin BGCs. Mutagenesis of the identified perylenequinone and melanin PKSs in C. beticola and E. fawcettii coupled with mass spectrometric metabolite analyses confirmed their roles in toxin and melanin production. 相似文献
92.
Cell–cell adhesion occurs in a broad spectrum of biological processes, of which yeast flocculation is an area of interest
for evolutionary scientists to brewers and winemakers. The flocculation mechanism is based on a lectin-carbohydrate interaction
but is not yet fully understood, although the first model dates back to the 1950s. This review will update the current understanding
of the complex mechanism behind yeast flocculation. Moreover, modern technologies to measure the forces involved in single
carbohydrate-lectin interactions, are discussed. The Flo1 protein has been extensively described as the protein responsible
for strong flocculation. Recently, more research has been directed to the detailed analysis of this flocculin. Due to the
advances in the field of bioinformatics, more information about Flo1p could be obtained via structurally or functionally related
proteins. Here, we review the current knowledge of the Flo1 protein, with a strong emphasis towards its structure. 相似文献
93.
Marcela Hernndez-Torres Rogrio Silva do Nascimento Monica Cardozo Rebouas Alexandra Cassado Kely Catarine Matteucci Maria Regina DImprio-Lima Jos Ronnie C. Vasconcelos Karina R. Bortoluci Jos Maria Alvarez Gustavo P. Amarante-Mendes 《Cell death & disease》2021,12(7)
Chagas disease is a life-threatening disorder caused by the protozoan parasite Trypanosoma cruzi. Parasite-specific antibodies, CD8+ T cells, as well as IFN-γ and nitric oxide (NO) are key elements of the adaptive and innate immunity against the extracellular and intracellular forms of the parasite. Bim is a potent pro-apoptotic member of the Bcl-2 family implicated in different aspects of the immune regulation, such as negative selection of self-reactive thymocytes and elimination of antigen-specific T cells at the end of an immune response. Interestingly, the role of Bim during infections remains largely unidentified. To explore the role of Bim in Chagas disease, we infected WT, Bim+/−, Bim−/− mice with trypomastigotes forms of the Y strain of T. cruzi. Strikingly, our data revealed that Bim−/− mice exhibit a delay in the development of parasitemia followed by a deficiency in the control of parasite load in the bloodstream and a decreased survival compared to WT and Bim+/− mice. At the peak of parasitemia, peritoneal macrophages of Bim−/− mice exhibit decreased NO production, which correlated with a decrease in the pro-inflammatory Small Peritoneal Macrophage (SPM) subset. A similar reduction in NO secretion, as well as in the pro-inflammatory cytokines IFN-γ and IL-6, was also observed in Bim−/− splenocytes. Moreover, an impaired anti-T. cruzi CD8+ T-cell response was found in Bim−/− mice at this time point. Taken together, our results suggest that these alterations may contribute to the establishment of a delayed yet enlarged parasitic load observed at day 9 after infection of Bim−/− mice and place Bim as an important protein in the control of T. cruzi infections.Subject terms: Cell death and immune response, Infectious diseases 相似文献
94.
Jan Willem Bek Adelbert De Clercq Hanna De Saffel Mieke Soenens Ann Huysseune P. Eckhard Witten Paul J. Coucke Andy Willaert 《Journal of fish biology》2021,98(4):1007-1017
One of the most frequently applied techniques in zebrafish (Danio rerio) research is the visualisation or manipulation of specific cell populations using transgenic reporter lines. The generation of these transgenic zebrafish, displaying cell- or tissue-specific expression of frequently used fluorophores such as Green Fluorescent Protein (GFP) or mCherry, is relatively easy using modern techniques. Fluorophores with different emission wavelengths and driven by different promoters can be monitored simultaneously in the same animal. Photoconvertible fluorescent proteins (pcFPs) are different from these standard fluorophores because their emission spectrum is changed when exposed to UV light, a process called photoconversion. Here, the benefits and versatility of using pcFPs for both single and dual fluorochrome imaging in zebrafish skeletal research in a previously generated osx:Kaede transgenic line are illustrated. In this line, Kaede, which is expressed under control of the osterix, otherwise known as sp7, promoter thereby labelling immature osteoblasts, can switch from green to red fluorescence upon irradiation with UV light. First, this study demonstrates that osx:Kaede exhibits an expression pattern similar to a previously described osx:nuGFP transgenic line in both larval and adult stages, hereby validating the use of this line for the imaging of immature osteoblasts. More in-depth experiments highlight different applications for osx:Kaede, such as lineage tracing and its combined use with in vivo skeletal staining and other transgenic backgrounds. Mineral staining in combination with osx:Kaede confirms osteoblast-independent mineralisation of the notochord. Osteoblast lineage tracing reveals migration and dedifferentiation of scleroblasts during fin regeneration. Finally, this study shows that combining two transgenics, osx:Kaede and osc:GFP, with similar emission wavelengths is possible when using a pcFP such as Kaede. 相似文献
95.
Rebekka Harting Jessica Starke Harald Kusch Stefanie Pöggeler Isabel Maurus Rabea Schlüter Manuel Landesfeind Ingo Bulla Minou Nowrousian Ronnie de Jonge Gertrud Stahlhut Katharina J. Hoff Kathrin P. Aßhauer Andrea Thürmer Mario Stanke Rolf Daniel Burkhard Morgenstern Bart P. H. J. Thomma James W. Kronstad Susanna A. Braus-Stromeyer Gerhard H. Braus 《Molecular Plant Pathology》2021,22(8):939-953
96.
Carolina S. Carvalho Brenna R. Forester Simone K. Mitre Ronnie Alves Vera L. Imperatriz‐Fonseca Silvio J. Ramos Luciana C. Resende‐Moreira Jos O. Siqueira Leonardo C. Trevelin Cecilio F. Caldeira Markus Gastauer Rodolfo Jaff 《Molecular ecology resources》2021,21(1):44-58
Despite the importance of climate‐adjusted provenancing to mitigate the effects of environmental change, climatic considerations alone are insufficient when restoring highly degraded sites. Here we propose a comprehensive landscape genomic approach to assist the restoration of moderately disturbed and highly degraded sites. To illustrate it we employ genomic data sets comprising thousands of single nucleotide polymorphisms from two plant species suitable for the restoration of iron‐rich Amazonian Savannas. We first use a subset of neutral loci to assess genetic structure and determine the genetic neighbourhood size. We then identify genotype‐phenotype‐environment associations, map adaptive genetic variation, and predict adaptive genotypes for restoration sites. Whereas local provenances were found optimal to restore a moderately disturbed site, a mixture of genotypes seemed the most promising strategy to recover a highly degraded mining site. We discuss how our results can help define site‐adjusted provenancing strategies, and argue that our methods can be more broadly applied to assist other restoration initiatives. 相似文献
97.
Goossens KV Stassen C Stals I Donohue DS Devreese B De Greve H Willaert RG 《Eukaryotic cell》2011,10(1):110-117
Saccharomyces cerevisiae cells possess a remarkable capacity to adhere to other yeast cells, which is called flocculation. Flocculation is defined as the phenomenon wherein yeast cells adhere in clumps and sediment rapidly from the medium in which they are suspended. These cell-cell interactions are mediated by a class of specific cell wall proteins, called flocculins, that stick out of the cell walls of flocculent cells. The N-terminal part of the three-domain protein is responsible for carbohydrate binding. We studied the N-terminal domain of the Flo1 protein (N-Flo1p), which is the most important flocculin responsible for flocculation of yeast cells. It was shown that this domain is both O and N glycosylated and is structurally composed mainly of β-sheets. The binding of N-Flo1p to D-mannose, α-methyl-D-mannoside, various dimannoses, and mannan confirmed that the N-terminal domain of Flo1p is indeed responsible for the sugar-binding activity of the protein. Moreover, fluorescence spectroscopy data suggest that N-Flo1p contains two mannose carbohydrate binding sites with different affinities. The carbohydrate dissociation constants show that the affinity of N-Flo1p for mono- and dimannoses is in the millimolar range for the binding site with low affinity and in the micromolar range for the binding site with high affinity. The high-affinity binding site has a higher affinity for low-molecular-weight (low-MW) mannose carbohydrates and no affinity for mannan. However, mannan as well as low-MW mannose carbohydrates can bind to the low-affinity binding site. These results extend the cellular flocculation model on the molecular level. 相似文献
98.
Sivakumaran TA Igo RP Kidd JM Itsara A Kopplin LJ Chen W Hagstrom SA Peachey NS Francis PJ Klein ML Chew EY Ramprasad VL Tay WT Mitchell P Seielstad M Stambolian DE Edwards AO Lee KE Leontiev DV Jun G Wang Y Tian L Qiu F Henning AK LaFramboise T Sen P Aarthi M George R Raman R Das MK Vijaya L Kumaramanickavel G Wong TY Swaroop A Abecasis GR Klein R Klein BE Nickerson DA Eichler EE Iyengar SK 《PloS one》2011,6(10):e25598
Complement factor H shows very strong association with Age-related Macular Degeneration (AMD), and recent data suggest that multiple causal variants are associated with disease. To refine the location of the disease associated variants, we characterized in detail the structural variation at CFH and its paralogs, including two copy number polymorphisms (CNP), CNP147 and CNP148, and several rare deletions and duplications. Examination of 34 AMD-enriched extended families (N = 293) and AMD cases (White N = 4210 Indian = 134; Malay = 140) and controls (White N = 3229; Indian = 117; Malay = 2390) demonstrated that deletion CNP148 was protective against AMD, independent of SNPs at CFH. Regression analysis of seven common haplotypes showed three haplotypes, H1, H6 and H7, as conferring risk for AMD development. Being the most common haplotype H1 confers the greatest risk by increasing the odds of AMD by 2.75-fold (95% CI = [2.51, 3.01]; p = 8.31×10−109); Caucasian (H6) and Indian-specific (H7) recombinant haplotypes increase the odds of AMD by 1.85-fold (p = 3.52×10−9) and by 15.57-fold (P = 0.007), respectively. We identified a 32-kb region downstream of Y402H (rs1061170), shared by all three risk haplotypes, suggesting that this region may be critical for AMD development. Further analysis showed that two SNPs within the 32 kb block, rs1329428 and rs203687, optimally explain disease association. rs1329428 resides in 20 kb unique sequence block, but rs203687 resides in a 12 kb block that is 89% similar to a noncoding region contained in ΔCNP148. We conclude that causal variation in this region potentially encompasses both regulatory effects at single markers and copy number. 相似文献
99.
Aims
We previously demonstrated Proline rich tyrosine kinase 2 (Pyk2) plays important roles in regulating tumor progression, migration and invasion in hepatocellular carcinoma (HCC). In this study, we aimed to examine the role of proline rich tyrosine kinase 2 (Pyk2) on cisplatin resistance in HCC and to explore its underlying molecular mechanism.Methodology/Principal Findings
Stable transfectants either overexpressing or suppressing Pyk2 were established in different HCC cell lines. MTT, colony formation and Annexin-V assays were employed to examine their in vitro responses to cisplatin. Xenograft ectopic and orthotopic nude mice models were generated to investigate the in vivo responses of them to cisplatin treatment. cDNA microarray was performed to identify Pyk2-induced genes which were further validated by quantitative real-time RT-PCR using clinical HCC samples. In vitro functional study demonstrated that Pyk2-overexpressing HCC transfectants exhibited relatively lower cytotoxicity, higher colony-forming ability and lower apoptosis to cisplatin compared with the control transfectants. Moreover, Pyk2 overexpressing HCC transfectants had a higher survival rate under cisplatin treatment by up-regulation of AKT phosphorylation. In vivo xenograft nude mice model demonstrated that Pyk2-overexpressing transfectants developed higher tolerance to cisplatin treatment together with less tumor necrosis and apoptosis. cDNA microarray analysis revealed that there were more than 4,000 genes differentially expressed upon overexpression of Pyk2. Several upregulated genes were found to be involved in drug resistance and invasion in cancers. Among them, the expression profiles of MDR1, GAGE1, STAT1 and MAP7 were significantly associated with the expression of Pyk2 in clinical HCC samples.Conclusions
Our results may suggest a new evidence of Pyk2 on promoting cisplatin resistance of HCC cells through preventing cell apoptosis, activation of AKT pathway and upregulation of drug resistant genes. 相似文献100.
Kim JJ Casteel DE Huang G Kwon TH Ren RK Zwart P Headd JJ Brown NG Chow DC Palzkill T Kim C 《PloS one》2011,6(4):e18413