RESUMO
Phenalenyl is a radical nanographene with a triangular shape hosting an unpaired electron with spin S = 1/2. The open-shell nature of the phenalenyl is expected to be retained in covalently bonded networks. As a first step, we report synthesis of the phenalenyl dimer by combining in-solution synthesis and on-surface activation and its characterization on Au(111) and on a NaCl decoupling layer by means of inelastic electron tunneling spectroscopy (IETS). IETS shows inelastic steps that are identified as singlet-triplet excitation arising from interphenalenyl exchange. Spin excitation energies with and without the NaCl decoupling layer are 48 and 41 meV, respectively, indicating significant renormalization due to exchange with Au(111) electrons. Furthermore, third-neighbor hopping-induced interphenalenyl hybridization is fundamental to explaining the position-dependent bias asymmetry of the inelastic steps and activation of kinetic interphenalenyl exchange. Our results pave the way for bottom-up synthesis of S = 1/2 spin-lattices with large exchange interactions.
RESUMO
Correction for 'Influence of 4f filling on electronic and magnetic properties of rare earth-Au surface compounds' by L. Fernandez et al., Nanoscale, 2020, 12, 22258-22267, DOI: 10.1039/D0NR04964F.
RESUMO
One-atom-thick rare-earth/noble metal (RE-NM) compounds are attractive materials to investigate two-dimensional magnetism, since they are easy to synthesize into a common RE-NM2 structure with high crystal perfection. Here we perform a comparative study of the GdAu2, HoAu2, and YbAu2 monolayer compounds grown on Au(111). We find the same atomic lattice quality and moiré superlattice periodicity in the three cases, but different electronic properties and magnetism. The YbAu2 monolayer reveals the characteristic electronic signatures of a mixed-valence configuration in the Yb atom. In contrast, GdAu2 and HoAu2 show the trivalent character of the rare-earth and ferromagnetic transitions below 22 K. Yet, the GdAu2 monolayer has an in-plane magnetic easy-axis, versus the out-of-plane one in HoAu2. The electronic bands of the two trivalent compounds are very similar, while the divalent YbAu2 monolayer exhibits different band features. In the latter, a strong 4f-5d hybridization is manifested in neatly resolved avoided crossings near the Fermi level. First principles theory points to a residual presence of empty 4f states, explaining the fluctuating valence of Yb in the YbAu2 monolayer.
RESUMO
Litho- and biostratigraphic data are provided of 5 stratigraphic sections in Romania covering the "Badenian" marine flooding that occurred in the Central Paratethys during the middle Miocene (Langhian). The dataset includes stratigraphic logs and descriptions of the profiles, and biostratigraphic analyses on calcareous nannofossils and foraminifera. In addition, characteristic stratigraphic features and representative fossils, including tiny Streptochilus foraminifera in the Campinita section in the SE Carpathian Foredeep, are presented in photographs. The data show that the flooding is characterized by the sudden abundance of Langhian calcareous nannofossils and foraminifera with a strong Mediterranean affinity.
RESUMO
We consider two 'comprehensive' modelling approaches for engineering fabrics. We distinguish the two approaches using the terms 'semi-discrete' and 'continuum', reflecting their natures. We demonstrate a fitting procedure, used to identify the constitutive parameters of the continuum model from predictions of the semi-discrete model, the parameters of which are in turn fitted to experimental data. We, then, check the effectiveness of the continuum model by verifying the correspondence between semi-discrete and continuum model predictions using test cases not previously used in the identification process. Predictions of both modelling approaches are compared against full-field experimental kinematic data, obtained using stereoscopic digital image correlation techniques, and also with measured force data. Being a reduced order model and being implemented in an implicit rather than an explicit finite-element code, the continuum model requires significantly less computational power than the semi-discrete model and could therefore be used to more efficiently explore the mechanical response of engineering fabrics.
RESUMO
AIMS: The aim of this work was to investigate the effects of biodynamic management with and without the addition of green manure, in comparison with organic management, on the microbiota in vineyards soil. METHODS AND RESULTS: High throughput sequencing was used to compare the taxonomic structure of the soil bacterial and fungal communities from vineyards managed with different methods (organic, biodynamic or biodynamic with green manure). Our results showed that microbial communities associated with biodynamic and organic farming systems were very similar, while green manure was the greatest source of soil microbial biodiversity and significantly changed microbial richness and community composition compared with other soils. Green manure also significantly enriched bacterial taxa involved in the soil nitrogen cycle (e.g. Microvirga sp., Pontibacter sp. and Nitrospira sp.). CONCLUSIONS: Our results showed that the diversity and composition of the microbial communities associated with biodynamic and organic farming systems were similar, indicating that the use of biodynamic preparations 500 and 501 did not cause any significant detectable changes to the soil microbial community in the short term, while the effects of green manure were significant in soil microbiota. SIGNIFICANCE AND IMPACT OF THE STUDY: The microbiological richness and structure of soil are used as a sensitive indicator of soil quality. The extension of organic/biodynamic farming, associated with green manure application, could contribute to increase the abundance of functional groups of biological and agronomical relevance and maintaining microbial biodiversity in vineyard soils.
Assuntos
Esterco/microbiologia , Microbiota/fisiologia , Agricultura Orgânica/métodos , Microbiologia do Solo , Vitis , Biodiversidade , Solo/químicaRESUMO
The effects of epidermal growth factor (EGF) concentrations (0, 10, 50, and 100ng/ml) on in vitro culture (IVC) of equine preantral follicles were evaluated using histology, estradiol and reactive oxygen species (ROS) production and metabolomics. After IVC, the percentage of normal follicles was lower (P<0.05) for all treatments when compared to non-cultured control. EGF 50ng/ml treatment had more (P<0.05) normal follicles at Day 7 of culture when compared with EGF 0 and 100ng/ml. EGF 50ng/ml had more (P<0.05) developing follicles than the 0ng/ml and 10ng/ml EGF treatments. Follicular and oocyte diameters were greater (P<0.05) with EGF 50ng/ml than the other cultured treatments, but similar (P>0.05) to the non-cultured control. From Day 1 to Day 7 estradiol production increased (P<0.05) in all EGF treatments. EGF 50ng/ml was the only treatment that maintained ROS production through IVC. Metabolomics profiles of the spent media indicated that eleven ions from variable influence in the projection (VIP) scores were higher represented in the EGF 50ng/ml treatment. In conclusion, EGF 50ng/ml treatment maintained follicle survival and ROS production, and promoted activation of cultured equine preantral follicles enclosed in ovarian tissue.
Assuntos
Fator de Crescimento Epidérmico/farmacologia , Cavalos , Metabolômica , Folículo Ovariano/efeitos dos fármacos , Técnicas de Cultura de Tecidos/veterinária , Animais , Meios de Cultura/química , Meios de Cultura/farmacologia , Relação Dose-Resposta a Droga , Fator de Crescimento Epidérmico/química , Estradiol/metabolismo , Feminino , Oócitos/metabolismo , Folículo Ovariano/fisiologia , Espécies Reativas de Oxigênio/metabolismoRESUMO
The aims of this study were: (1) to evaluate the effect of different insulin concentrations, alone or in combination with either a fixed FSH concentration or increasing FSH concentrations on the in vitro culture of isolated caprine preantral follicles and (2) to analyze the efficiency of two IVM media and maturation culture systems (with or without coculture with in vivo grown oocytes) on the meiosis resumption. Secondary follicles were cultured for 18 days in a basic medium supplemented with low- or high-insulin concentration alone or with a fixed FSH concentration or with increasing FSH concentrations. Oocytes grown in vivo or in vitro were matured alone or cocultured. The high-insulin concentration associated with fixed FSH treatment had higher meiotic resumption rate (P < 0.05) and was the only treatment capable of producing oocytes in metaphase II. The rates of germinal vesicle, germinal vesicle breakdown, metaphase I, metaphase II (MII), meiotic resumption, and oocyte diameter were similar between the maturation media. In conclusion, a basic medium supplemented with 10-µg/mL insulin and 100-µg/mL FSH throughout the culture period improved meiotic resumption rate and produced MII oocytes from caprine preantral follicles cultured in vitro. The MII rate was similar between in vivo and in vitro grown oocytes ≥110 µm.
Assuntos
Técnicas de Cocultura/veterinária , Hormônio Foliculoestimulante/farmacologia , Técnicas de Maturação in Vitro de Oócitos/veterinária , Insulina/farmacologia , Oócitos/crescimento & desenvolvimento , Folículo Ovariano/efeitos dos fármacos , Animais , Meios de Cultura , Feminino , Cabras , Técnicas de Maturação in Vitro de Oócitos/métodos , MeioseRESUMO
Cytokinesis, the physical separation of daughter cells at the end of cell cycle, is commonly considered a highly stereotyped phenomenon. However, in some specialized cells this process may involve specific molecular events that are still largely unknown. In mammals, loss of Citron-kinase (CIT-K) leads to massive cytokinesis failure and apoptosis only in neuronal progenitors and in male germ cells, resulting in severe microcephaly and testicular hypoplasia, but the reasons for this specificity are unknown. In this report we show that CIT-K modulates the stability of midbody microtubules and that the expression of tubulin ß-III (TUBB3) is crucial for this phenotype. We observed that TUBB3 is expressed in proliferating CNS progenitors, with a pattern correlating with the susceptibility to CIT-K loss. More importantly, depletion of TUBB3 in CIT-K-dependent cells makes them resistant to CIT-K loss, whereas TUBB3 overexpression increases their sensitivity to CIT-K knockdown. The loss of CIT-K leads to a strong decrease in the phosphorylation of S444 on TUBB3, a post-translational modification associated with microtubule stabilization. CIT-K may promote this event by interacting with TUBB3 and by recruiting at the midbody casein kinase-2α (CK2α) that has previously been reported to phosphorylate the S444 residue. Indeed, CK2α is lost from the midbody in CIT-K-depleted cells. Moreover, expression of the nonphosphorylatable TUBB3 mutant S444A induces cytokinesis failure, whereas expression of the phospho-mimetic mutant S444D rescues the cytokinesis failure induced by both CIT-K and CK2α loss. Altogether, our findings reveal that expression of relatively low levels of TUBB3 in mitotic cells can be detrimental for their cytokinesis and underscore the importance of CIT-K in counteracting this event.
Assuntos
Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Microtúbulos/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Tubulina (Proteína)/metabolismo , Animais , Células Cultivadas , Células HeLa , Humanos , Masculino , Camundongos , Microtúbulos/química , Especificidade de Órgãos , FosforilaçãoRESUMO
Impairment of synaptic function can lead to neuropsychiatric disorders collectively referred to as synaptopathies. The SNARE protein SNAP-25 is implicated in several brain pathologies and, indeed, brain areas of psychiatric patients often display reduced SNAP-25 expression. It has been recently found that acute downregulation of SNAP-25 in brain slices impairs long-term potentiation; however, the processes through which this occurs are still poorly defined. We show that in vivo acute downregulation of SNAP-25 in CA1 hippocampal region affects spine number. Consistently, hippocampal neurons from SNAP-25 heterozygous mice show reduced densities of dendritic spines and defective PSD-95 dynamics. Finally, we show that, in brain, SNAP-25 is part of a molecular complex including PSD-95 and p140Cap, with p140Cap being capable to bind to both SNAP-25 and PSD-95. These data demonstrate an unexpected role of SNAP-25 in controlling PSD-95 clustering and open the possibility that genetic reductions of the protein levels - as occurring in schizophrenia - may contribute to the pathology through an effect on postsynaptic function and plasticity.
Assuntos
Espinhas Dendríticas/fisiologia , Guanilato Quinases/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas de Membrana/metabolismo , Proteína 25 Associada a Sinaptossoma/metabolismo , Animais , Espinhas Dendríticas/metabolismo , Proteína 4 Homóloga a Disks-Large , Células HEK293 , Hipocampo/metabolismo , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Morfogênese , Plasticidade Neuronal/fisiologia , Sinapses/metabolismo , TransfecçãoRESUMO
The DNA glycosylase MUTYH (mutY homolog (Escherichia coli)) counteracts the mutagenic effects of 8-oxo-7,8-dihydroguanine (8-oxodG) by removing adenine (A) misincorporated opposite the oxidized purine. Biallelic germline mutations in MUTYH cause the autosomal recessive MUTYH-associated adenomatous polyposis (MAP). Here we designed new tools to investigate the biochemical defects and biological consequences associated with different MUTYH mutations in human cells. To identify phenotype(s) associated with MUTYH mutations, lymphoblastoid cell lines (LCLs) were derived from seven MAP patients harboring missense as well as truncating mutations in MUTYH. These included homozygous p.Arg245His, p.Gly264TrpfsX7 or compound heterozygous variants (p.Gly396Asp/Arg245Cys, p.Gly396Asp/Tyr179Cys, p.Gly396Asp/Glu410GlyfsX43, p.Gly264TrpfsX7/Ala385ProfsX23 and p.Gly264TrpfsX7/Glu480del). DNA glycosylase assays of MAP LCL extracts confirmed that all these variants were defective in removing A from an 8-oxoG:A DNA substrate, but retained wild-type OGG1 activity. As a consequence of this defect, MAP LCLs accumulated DNA 8-oxodG in their genome and exhibited a fourfold increase in spontaneous mutagenesis at the PIG-A gene compared with LCLs from healthy donors. They were also hypermutable by KBrO3--a source of DNA 8-oxodG--indicating that the relatively modest spontaneous mutator phenotype associated with MUTYH loss can be significantly enhanced by conditions of oxidative stress. These observations identify accumulation of DNA 8-oxodG and a mutator phenotype as likely contributors to the pathogenesis of MUTYH variants.
Assuntos
Dano ao DNA , DNA Glicosilases/genética , DNA Glicosilases/metabolismo , Instabilidade Genômica , Estresse Oxidativo , 8-Hidroxi-2'-Desoxiguanosina , Polipose Adenomatosa do Colo/genética , Polipose Adenomatosa do Colo/metabolismo , Adulto , Linhagem Celular , Reparo do DNA , Desoxiguanosina/análogos & derivados , Desoxiguanosina/metabolismo , Ativação Enzimática , Feminino , Expressão Gênica , Heterozigoto , Humanos , Masculino , Proteínas de Membrana/genética , Pessoa de Meia-Idade , Mutação , Taxa de Mutação , FenótipoRESUMO
The aim of the present study was to investigate the level of information on the chemical structures and relative abundances of lipids present in cat and dog oocytes by matrix-assisted laser desorption mass spectrometry (MALDI-MS). The MALDI-MS approach requires a simple analysis workflow (no lipid extraction) and few samples (two or three oocytes per analysis in this work) providing concomitant profiles of both intact phospholipids such as sphingomyelins (SM) and phosphatidylcholines (PC) as well as triacylglycerols (TAG). The lipids were detected in oocytes by MALDI using dihydroxybenzoic acid (DHB) as the matrix. The most abundant lipid present in the MS profiles of bitch and queen oocytes was a PC containing 34 carbons and one unsaturation [PC (34:1)]. Oocytes of these two species are characterized by differences in PC and TAG profiles detected qualitatively as well as by means of principal component analysis (PCA). Cat oocytes were mainly discriminated by more intense C52 and C54 TAG species and a higher number of unsaturations, indicating predominantly linoleic and oleic fatty acyl residues. Comparison of the lipid profile of bitch and queen oocytes with that of bovine oocytes revealed some similarities and also some species specificity: TAG species present in bovine oocytes were also present in bitches and queens; however, a more pronounced contribution of palmitic, stearic and oleic fatty acid residues was noticed in the lipid profile of bovine oocytes. MALDI-MS provides novel information on chemical lipid composition in canine and feline oocytes, offering a suitable tool to concomitantly monitor, in a nearly direct and simple fashion the composition of phospholipids and TAG. This detailed information is highly needed to the development of improved protocols for in vitro culture and cryopreservation of cat and dog oocytes.
Assuntos
Gatos/fisiologia , Lipídeos/química , Oócitos/química , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/veterinária , Animais , Cães/fisiologia , Feminino , Lipídeos/fisiologia , Oócitos/fisiologiaRESUMO
INTRODUCTION: preeclampsia is characterized by intense inflammatory response and an anti-angiogenic state. Maternal obesity has been considered to have important impact on the genesis of preeclampsia as lipotoxicity leads to maternal endothelial dysfunction and chronic inflammation. Here we investigate the plasma lipid profile of preeclamptic women. OBJECTIVES: identify possible lipid biomarkers for preeclampsia. METHODS: this study included 8 pregnant women with early-onset preeclampsia (before 34weeks gestation) and 8 normal pregnant women. Each patient in the preeclampsia group was matched to a patient in the control group according to gestational age at the time of sample collection. All patients in the control group were followed until term and had normal outcomes. To investigate the lipid profile, lipids were extracted from plasma samples using the Bligh-Dyer protocol and the extracts were subjected to MALDI-TOF Mass Spectrometry. Data matrix was exported for partial least squares discriminant analysis. All the variables analysed were sorted by a score number named Variable Importance in the Projection. The major discriminant variables were selected and underwent to Mann-Whitney U test. RESULTS: a total of 1290 ions were initially identified during lipidomic assessment. Twelve m/z signals were highlighted as the most important lipids for the discrimination of patients with preeclampsia. The identification of these differential lipids was carried out through Lipid Database Search. The main classes identified were Glycerophosphocholines [GP01], Glycerophosphoserines [GP03], Glycerophosphoglycerols [GP04], Glycosyldiradylglycerols [GL05] and Glycerophosphates [GP10]. CONCLUSION: Our results suggest that some lipid species may be potential biomarkers for early-onset preeclampsia.
RESUMO
We have recently shown that the adaptor protein p140Cap regulates tumor properties in terms of cell motility and growth. Here, by using the highly metastatic rat adenocarcinoma cell line MTLn3-epidermal growth factor receptor (EGFR), we assess the role of p140Cap in metastasis formation. Orthotopic transplantation of MTLn3-EGFR cells over-expressing p140Cap in Rag2(-/-)γ(c)(-/-) mice resulted in normal primary tumor growth compared with the controls. Strikingly, p140Cap over-expression causes an 80% inhibition in the number of lung metastases. p140Cap over-expressing cells display a 50% reduction in directional cell migration, an increased number and size of focal adhesions, and a strong impairment in the ability to invade in a 3D matrix. p140Cap over-expression affects EGFR signaling and tyrosine phosphorylation of cortactin in response to EGF stimulation. Intriguingly, p140Cap associates with cortactin via interaction with its second proline-rich domain to the cortactin SH3 domain. The phosphomimetic cortactin tyrosine 421 mutant rescues migration and invasive properties in p140Cap over-expressing cells. Taken together, these data demonstrate that p140Cap suppresses the invasive properties of highly metastatic breast carcinoma cells by inhibiting cortactin-dependent cell motility.
Assuntos
Proteínas Adaptadoras de Transporte Vesicular/metabolismo , Cortactina/metabolismo , Neoplasias Mamárias Experimentais/metabolismo , Proteínas Adaptadoras de Transporte Vesicular/genética , Adenocarcinoma/genética , Adenocarcinoma/metabolismo , Adenocarcinoma/patologia , Animais , Linhagem Celular Tumoral , Movimento Celular , Cortactina/genética , Fator de Crescimento Epidérmico/farmacologia , Receptores ErbB/genética , Receptores ErbB/metabolismo , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Células HEK293 , Humanos , Imuno-Histoquímica , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/secundário , Neoplasias Mamárias Experimentais/genética , Neoplasias Mamárias Experimentais/patologia , Camundongos , Camundongos Knockout , Microscopia de Fluorescência por Excitação Multifotônica , Invasividade Neoplásica , Metástase Neoplásica , Transplante de Neoplasias , Fosforilação/efeitos dos fármacos , Ligação Proteica , Interferência de RNA , Ratos , Transplante HeterólogoRESUMO
Juglans nigra and Juglans regia are two highly economically important species for wood and fruit production that are susceptible to anthracnose caused by Gnomonia leptostyla. The identification of genotypes resistant to anthracnose could represent a valid alternative to agronomic and chemical management. In this study, we analyzed 72 walnut genotypes that showed a variety of resistance phenotypes in response to natural infection. According to the disease severity rating and microsatellite fingerprinting analysis, these genotypes were divided into three main groups: (40) J. nigra resistant, (1) J. nigra susceptible, and (31) J. regia susceptible. Data on leaf emergence rates and analysis of in vivo pathogenicity indicated that the incidence of anthracnose disease in the field might be partially conditioned by two key factors: the age and/or availability of susceptible leaves during the primary infection of fungus (avoidance by late flushing) and partial host resistance. NBS profiling approach, based on PCR amplification with an adapter primer for an adapter matching a restriction enzyme site and a degenerate primer targeting the conserved motifs present in the NBS domain of NBS-LRR genes, was applied. The results revealed the presence of a candidate marker that correlated to a reduction in anthracnose incidence in 72 walnut genotypes.
Assuntos
Colletotrichum/fisiologia , Juglans , Doenças das Plantas/microbiologia , Análise por Conglomerados , DNA de Plantas/análise , DNA de Plantas/isolamento & purificação , Resistência à Doença , Genótipo , Interações Hospedeiro-Patógeno , Repetições de Microssatélites , Técnicas de Amplificação de Ácido Nucleico , Fenótipo , Folhas de Planta/química , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/microbiologia , Estatísticas não ParamétricasRESUMO
Lung cancer is the leading cause of cancer death worldwide. The epidermal growth factor receptor (EGFR) represents the main target for non-small cell lung cancer (NSCLC) therapy, as its overexpression or constitutive activation contributes to malignancy and correlates with poor prognosis. Our previous work demonstrated that in epithelial cells ß1 integrin is required for propagating EGFR signaling from the plasma membrane to the nucleus. In this study, we silenced ß1 integrin in human NSCLC A549 cells. The ß1 integrin-silenced cells show a defective activation of the EGFR signaling cascade, leading to decreased in vitro proliferation, enhanced sensitivity to cisplatin and Gefitinib, impaired migration and invasive behavior. Inhibitory effects on tumor growth and on the EGFR pathway were also observed in in vivo experiments. Moreover, ß1 integrin silencing increases the amount of EGFR on the cell surface, suggesting that ß1 integrin is required for efficient constitutive EGFR turnover at the cell membrane. Although the rate of EGF internalization and recycling is not affected in silenced cells, EGFR signaling is recovered only by expression of the Rab-coupling protein RCP, indicating that ß1 integrin sustains the endocytic machinery required for EGFR signaling. Overall, these results show that ß1 integrin is an essential regulator of EGFR signaling and tumorigenic properties of lung cancer cells, and that its silencing might represent an adjuvant approach to anti-EGFR therapy.
Assuntos
Carcinoma Pulmonar de Células não Pequenas/metabolismo , Carcinoma Pulmonar de Células não Pequenas/patologia , Receptores ErbB/metabolismo , Integrina beta1/metabolismo , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Anticorpos Monoclonais , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Cisplatino/farmacologia , Fator de Crescimento Epidérmico/metabolismo , Gefitinibe , Humanos , Integrina beta1/genética , Neoplasias Pulmonares/tratamento farmacológico , Proteínas de Membrana/metabolismo , Camundongos , Camundongos SCID , Invasividade Neoplásica , Transplante de Neoplasias , Quinazolinas/farmacologia , Interferência de RNA , RNA Interferente Pequeno , Transdução de Sinais , Transplante HeterólogoRESUMO
The adaptor protein p140Cap/SNIP is a novel Src-binding protein that regulates Src activation through C-terminal Src kinase (Csk). Here, by gain and loss of function approaches in breast and colon cancer cells, we report that p140Cap immobilizes E-cadherin at the cell membrane and inhibits EGFR and Erk1/2 signalling, blocking scatter and proliferation of cancer cells. p140Cap-dependent regulation of E-cadherin/EGFR cross-talk and cell motility is due to the inhibition of Src kinase. However, rescue of Src activity is not sufficient to restore Erk1/2 phosphorylation and proliferation. Indeed, p140Cap also impairs Erk1/2 phosphorylation by affecting Ras activity, downstream to the EGFR. In conclusion, p140Cap stabilizes adherens junctions and inhibits EGFR and Ras signalling through the dual control of both Src and Ras activities, thus affecting crucial cancer properties such as invasion and growth. Interestingly, p140Cap expression is lost in more aggressive human breast cancers, showing an inverse correlation with EGFR expression. Therefore, p140Cap mechanistically behaves as a tumour suppressor that inhibits signalling pathways leading to aggressive phenotypes.
Assuntos
Proteínas Adaptadoras de Transporte Vesicular/metabolismo , Caderinas/metabolismo , Movimento Celular , Receptores ErbB/metabolismo , Neoplasias/patologia , Receptor Cross-Talk , Transdução de Sinais , Proteínas ras/metabolismo , Animais , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Caderinas/química , Linhagem Celular Tumoral , Membrana Celular/metabolismo , Proliferação de Células , Fator de Crescimento Epidérmico/farmacologia , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Camundongos , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Invasividade Neoplásica , Neoplasias/genética , Neoplasias/metabolismo , Estabilidade Proteica , Transdução de Sinais/efeitos dos fármacos , Quinases da Família src/metabolismoRESUMO
AIMS: To assess the effect of different concentrations of gossypol (0, 2, 4, 10 and 20 mg l(-1)) in combination with NaCl and Na(2)SO(4) (20 mS cm(-1)) on the conidial germination and viability of Fusarium oxysporum f.sp. vasinfectum (Fov). METHODS AND RESULTS: A multinomial logistic model was developed to estimate the germination probability of Fov. The inhibitory effect was markedly evident at the two highest concentrations of gossypol; it varied among the isolates tested and with time, and it was attenuated by the presence of sodium salts. The inhibition was temporary as the germination probability increased after 8 h. Fluorescent staining revealed that gossypol either killed the conidia or retarded the elongation of the germ tubes. CONCLUSION: Fov showed the ability to overcome gossypol inhibition over time, and the inhibitory effect is reduced under saline conditions. Differential responses among Fov isolates to the presence of gossypol suggest that gossypol tolerance is genetically determined in the pathogen. SIGNIFICANCE AND IMPACT OF THE STUDY: This study suggests that selecting for high plant gossypol cultivars would have minimal effect on the overall Fov resistance of cotton. A new statistical model was developed to explore the statistical significance of plant-pathogen interactions.
Assuntos
Óleo de Sementes de Algodão , Fusarium/efeitos dos fármacos , Gossipol/farmacologia , Microbiologia do Solo , Fusarium/fisiologia , Modelos Logísticos , Probabilidade , Cloreto de Sódio/farmacologia , Sulfatos/farmacologiaRESUMO
The Parco Nord Milano, Italy is a 600-ha green area (45°53'71â³N, 9°20'97â³E). Since the spring of 2002, extensive and unknown decline was observed on 20-year-old sycamore (Acer pseudoplatanus), red oak (Quercus rubra), and English oak (Q. robur) plantations. The trees showed branch and twig dieback associated with bark cankering along the whole stem and an irregular to wilted crown. A closer inspection of the inner part of the symptomatic trunk and roots revealed a dark bluish tissue discoloration. From the symptomatic trunk and root tissue, a dark gray abundant mycelium was consistently isolated on potato dextrose agar (PDA). The sequenced internal transcribed spacer (ITS) regions of rDNA (GenBank Accession Nos. DQ198265, DQ198266, and DQ198267) showed 99% identity to Botryosphaeria dothidea strain CBS110302 (GenBank Accession No. AY259092). A Fusicoccum sp. with black pycnidia was consistently collected from the cankers. The conidia were hyaline, aseptate, fusiform to narrowly ellipsoidal, with a truncate base (22 × 4.5 µm), referred to as Fusicoccum aesculi (CBS identification), the anamorph of B. dothidea (2). Pathogenicity tests were conducted for all three hosts by stem inoculation on 18-month-old seedlings growing in plastic pots containing a 2:1 turf/sand mixture. Two experiments were conducted using two inoculation techniques. In the first trial, 6-mm-diameter mycelial plugs of B. dothidea were applied to 6-mm-long bark wounds. The same inoculation method was used for application to bark without wounding. Control seedlings were inoculated with sterile agar plugs in a similar fashion as above. Inoculated and control seedlings were kept in a growth chamber and watered once per week. In the second trial, segments of branches 15-cm long were inoculated with 6-mm-diameter B. dothidea plugs (1), with and without any wounding. Control segments of branches were treated with sterile agar plugs in place of fungal mycelium. The branches were incubated at 23°C in moist chambers. For both experiments, the inoculated stem portions were wrapped with Parafilm to prevent desiccation. There were three replicate seedlings per inoculation technique, experiment, and plant species. After 2 months, all seedlings showed bark cankers and pycnidial formation, while the controls were symptomless. An inner dark bluish stem tissue discoloration was observed. The symptoms were more abundant on the segment of branches where the inoculum was applied to the wounded bark. B. dothidea was successfully reisolated, confirming Koch's postulates. To our knowledge, although it is accepted as synonymous of B. berengeriana (2), this is the first report of B. dothidea on sycamore, red oak, and English oak in Italy. The fungus was previously reported in Italy to cause canker on Platanus spp. References: (1) M. E. Sanchez et al. Plant Dis. 87:1515, 2003. (2) B. Slippers et al. Mycologia 96:83, 2004.