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1.
J Nanosci Nanotechnol ; 20(4): 2442-2451, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-31492260

RESUMO

Two methods of TiO2 addition were applied to prepare hydroxyapatite/TiO2 (HA/TiO2) composite, i.e., in-situ hydrolysis TiO2 in HA powders (N-HA/TiO2) and mixing commercial nano-sized HA and TiO2 powder (C-HA/TiO2). Effects of TiO2 addition methods and sintering temperatures on phase, microstructure and microhardness were investigated for pressureless sintered HA/TiO2 composites, and pure HA was investigated for comparison. Results show that TiO2 from both in-situ hydrolysis and mixing commercial powder presented similar effects on phase structures and composition, and trended to chemically react with HA in the HA/TiO2 composites at high sintering temperature. Weight loss for different composites was investigated by thermal analysis. Sintering behavior for two different composite was also discussed. The TiO2 from in-situ hydrolysis can effectively enhance the TiO2 distribution and densification for the N-HA/TiO2 composites. Both two different composites showed typical grain growth and pore formation with the increase of sintering temperature. The N-HA/TiO2 composite had a lower porosity, higher shrinkage and microhardness than that of C-HA/TiO2 composite at sintering temperature from 700 °C to 1100 °C.

2.
Artigo em Inglês | MEDLINE | ID: mdl-31574938

RESUMO

Objective: The association between phthalates and endometriosis risk is inconclusive. This meta-analysis aims to evaluate the association between five different phthalate metabolites and endometriosis, based on current evidence. Methods: The literature included PubMed, WOS (web of science), and EMBASE, published until 3 March 2019. We selected the related literature and evaluated the relationship between phthalates exposure and endometriosis risk. All statistical analyses were conducted with STATA version 12.0. Results: Data from eight studies were used in this review. The results of this analysis showed that mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) exposure was potentially associated with endometriosis (OR = 1.246, 95% CI = 1.003-1.549). We have not found positive results in mono(2-ethylhexyl) phthalate (MEHP), monoethyl phthalate (MEP), monobenzyl phthalate (MBzP) and mono(2-ethyl-5-oxohexyl) phthalate (MEOHP) analyses (MEHP: OR = 1.089, 95% CI = 0.858-1.383; MEP: OR = 1.073, 95% CI = 0.899-1.282; MBzP: OR = 0.976, 95% CI = 0.810-1.176; MEOHP: OR = 1.282, 95% CI = 0.874-1.881). In subgroup analyses for regions, the associations were significant between MEHHP and endometriosis in Asia (OR = 1.786, 95% CI = 1.005-3.172, I² = 0%), but not in USA (OR = 1.170, 95% CI = 0.949-1.442, I² = 45.6%). Conclusions: Our findings suggested a potential statistical association between MEHHP exposure and endometriosis, particularly, the exposure of MEHHP might be a potential risk for women with endometriosis in Asia. However, positive associations between the other four Phthalate acid esters (PAEs) and endometriosis was not found. Given the weak strength of the results, well-designed cohort studies, with large sample sizes, should be performed in future.

3.
Cells ; 8(10)2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31575017

RESUMO

Long non-coding RNAs (lncRNAs) are versatile regulators of gene expression and play crucial roles in diverse biological processes. Epithelial-mesenchymal transition (EMT) is a cellular program that drives plasticity during embryogenesis, wound healing, and malignant progression. Increasing evidence shows that lncRNAs orchestrate multiple cellular processes by modulating EMT in diverse cell types. Dysregulated lncRNAs that can impact epithelial plasticity by affecting different EMT markers and target genes have been identified. However, our understanding of the landscape of lncRNAs important in EMT is far from complete. Here, we summarize recent findings on the mechanisms and roles of lncRNAs in EMT and elaborate on how lncRNAs can modulate EMT by interacting with RNA, DNA, or proteins in epigenetic, transcriptional, and post-transcriptional regulation. This review also highlights significant EMT pathways that may be altered by diverse lncRNAs, thereby suggesting their therapeutic potential.

4.
Artigo em Inglês | MEDLINE | ID: mdl-31564506

RESUMO

BACKGROUND: Increasing evidence indicates that Six2 contributes to tumorigenesis in various tumor including hepatocellular carcinoma (HCC). This study aimed to determine the role of Six2 in HCC and to elucidate the association of Six2 with clinical pathological characteristics. METHODS: The expressions of Six2 in HCC tumor, para-tumor tissue and portal vein tumor thrombus (PVTT) were detected by tissue microarray technique, immunohistochemistry, real-time RT-PCR and Western blotting. Chi-square and Kaplan-Meier analysis were used to analyze the correlation between Six2 expression and prognosis of HCC patients. Lentivirus mediated Six2 knockdown, spheroid formation assay, proliferation assay and subcutaneous tumor implantation were performed to determine the function of Six2. RESULTS: In 274 HCC samples, Six2 was strongly expressed. Kaplan-Meier analysis revealed that high expression of Six2 was correlated with a shorter overall survival (OS) and disease-free survival (DFS). Moreover, Six2 expression was associated with sex, alpha-fetoprotein, tumor size and portal vein invasion. Six2 was highly expressed in PVTT. Six2 knockdown inhibited HCC cell lines proliferation, migration, and self-renewal in vitro and in vivo. In addition, low-expression of Six2 weakened TGF-ß induced Smad4 activation and epithelial-mesenchymal transition in HCC cell lines. CONCLUSIONS: Elevated Six2 expression in HCC tumor patients was associated with negative prognosis. Upregulated Six2 promoted tumor growth and facilitated HCC metastasis via TGF-ß/Smad signal pathway.

5.
Sci Rep ; 9(1): 14132, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31575956

RESUMO

Transient receptor potential melastatin channel subfamily member 2 (TRPM2) has an essential role in protecting cell viability through modulation of oxidative stress. TRPM2 is highly expressed in cancer. When TRPM2 is inhibited, mitochondria are dysfunctional, ROS levels are increased, and cell viability is reduced. Here, the importance of NF-E2-related factor (Nrf2) in TRPM2-mediated suppression of oxidant stress was explored. In TRPM2 depleted cells, antioxidant cofactors glutathione, NADPH, and NADH were significantly reduced. Cytoplasmic and nuclear expression of Nrf2 and of IQGAP1, a modulator of Nrf2 stability regulated by intracellular calcium, were decreased. Antioxidant enzymes transcriptionally regulated by Nrf2 and involved in GSH, NADPH, and NADH generation were significantly lower including PRX1 and PRX3, GPX4, GSTP1, GCLC, and MTHFD2. The glutamine pathway leading to GSH production was suppressed, and ATP and GTP levels were impaired. Reconstitution with wild type TRPM2 or Nrf2, but not TRPM2 pore mutant E960D, rescued expression of enzymes downstream of Nrf2 and restored GSH and GTP. Cell viability, ROS, NADPH, NADH, and ATP levels were fully rescued by TRPM2 and partially by Nrf2. These data show that TRPM2 maintains cell survival following oxidative stress through modulation of antioxidant pathways and cofactors regulated by Nrf2.

6.
Biomolecules ; 9(10)2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31591300

RESUMO

Nanobodies are one-tenth the size of conventional antibodies and are naturally obtained from the atypical heavy-chain-only antibodies present in camelids. Their small size, high solubility, high stability, and strong resilience to organic solvents facilitate their use as novel analytical reagents in immunochemistry. In this study, specific nanobodies against pesticide carbofuran were isolated and characterized from an immunized library via phage display platform. We further established an indirect competitive enzyme-linked immunosorbent assay (ELISA) using nanobody Nb316 to detect carbofuran in vegetable and fruit samples. The results showed a half-maximal inhibitory concentration (IC50) of 7.27 ng/mL and a detection limit of 0.65 ng/mL. A simplified sample pretreatment procedure omitting the evaporation of organic solvent was used. The averaged recovery rate of spiked samples ranged between 82.3% and 103.9%, which correlated with that of standard UPLC-MS/MS method. In conclusion, a nanobody with high specificity for carbofuran was characterized, and a nanobody-based sensitive immunoassay for simple and rapid detection of carbofuran in real samples was validated.

7.
Colloids Surf B Biointerfaces ; 184: 110516, 2019 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-31569002

RESUMO

The effective assessment of platelet activation is an important component of the evaluation of cardiovascular implants. Currently, most evaluation is performed based on the ISO 10993-4 international standard. However, the methods specified in this standard were originally designed for non-degradable materials, and the applicability of these methods to evaluate degradable materials has not been carefully assessed. Here, the platelet activation response was evaluated (using blood from health rabbits) for three typical degradable materials (collagen, polylactic acid, and hydroxyapatite) by measuring the widely used molecular markers CD62 P, CD63, and CD40 L and the three molecular markers PF4, ß-TG, and TXB2 that are referenced in the ISO 10993-4 standard. The variations of these six markers were compared in the simulated degradation of the three test materials. The results showed differences in platelet activation with degradation that were strongly related to the surface physicochemical properties. Changes in the surface roughness and contact angle of the materials correlated with changes in the degree of platelet activation. The six tested platelet activation molecular markers show promise for assessment of platelet function in degradable medical devices, providing guidance for quality control strategies and the design and improvement of safe medical devices.

8.
Molecules ; 24(20)2019 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-31600968

RESUMO

Lactoferrin (LF) is a soluble glycoprotein of the transferring family found in most biological fluids, functioning as a major first line defense molecule against infection in mammals. It also shows certain anti-tumor activity, but its clinical application in tumor therapy is limited because high dosage is required. In this study, we demonstrate that M860, a monoclonal antibody against human LF (hLF), could significantly increase the anti-tumor potential of low dosage hLF by forming LF-containing immune complex (IC). Human monocytes primed with LF-IC, but not hLF or M860 alone, or control ICs, showed strong tumoricidal activity on leukemia cell lines Jurkat and Raji through induction of secreted Granzyme B (GzB). LF-IC is able to colligate membrane-bound CD14 (a TLR4 co-receptor) and FcγRIIa (a low affinity activating Fcγ receptor) on the surface of human monocytes, thereby triggering the Syk-PI3K-AKT-mTOR pathway leading to GzB production. Our work identifies a novel pathway for LF-mediated tumoricidal activity and may extend the clinical application of LF in tumor therapy.

9.
Cell Death Dis ; 10(10): 766, 2019 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-31601784

RESUMO

The yolk sac is the first site of blood-cell production during embryonic development in both murine and human. Heat shock proteins (HSPs), including HSP70 and HSP27, have been shown to play regulatory roles during erythropoiesis. However, it remains unknown whether HSP60, a molecular chaperone that resides mainly in mitochondria, could also regulate early erythropoiesis. In this study, we used Tie2-Cre to deactivate the Hspd1 gene in both hematopoietic and vascular endothelial cells, and found that Tie2-Cre+Hspd1f/f (HSP60CKO) mice were embryonic lethal between the embryonic day 10.5 (E10.5) and E11.5, exhibiting growth retardation, anemia, and vascular defects. Of these, anemia was observed first, independently of vascular and growth phenotypes. Reduced numbers of erythrocytes, as well as an increase in cell apoptosis, were found in the HSP60CKO yolk sac as early as E9.0, indicating that deletion of HSP60 led to abnormality in yolk sac erythropoiesis. Deletion of HSP60 was also able to reduce mitochondrial membrane potential and the expression of the voltage-dependent anion channel (VDAC) in yolk sac erythrocytes. Furthermore, cyclosporine A (CsA), which is a well-recognized modulator in regulating the opening of the mitochondrial permeability transition pore (mPTP) by interacting with Cyclophilin D (CypD), could significantly decrease cell apoptosis and partially restore VDAC expression in mutant yolk sac erythrocytes. Taken together, we demonstrated an essential role of HSP60 in regulating yolk sac cell survival partially via a mPTP-dependent mechanism.

10.
Sci Rep ; 9(1): 14541, 2019 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-31601882

RESUMO

Necrotic enteritis (NE) caused by Clostridium perfringens infection has reemerged as a prevalent poultry disease worldwide due to reduced usage of prophylactic antibiotics under consumer preferences and regulatory pressures. The lack of alternative antimicrobial strategies to control this disease is mainly due to limited insight into the relationship between NE pathogenesis, microbiome, and host responses. Here we showed that the microbial metabolic byproduct of secondary bile acid deoxycholic acid (DCA), at as low as 50 µM, inhibited 82.8% of C. perfringens growth in Tryptic Soy Broth (P < 0.05). Sequential Eimeria maxima and C. perfringens challenges significantly induced NE, severe intestinal inflammation, and body weight (BW) loss in broiler chickens. These negative effects were diminished (P < 0.05) by 1.5 g/kg DCA diet. At the cellular level, DCA alleviated NE-associated ileal epithelial death and significantly reduced lamina propria cell apoptosis. Interestingly, DCA reduced C. perfringens invasion into ileum (P < 0.05) without altering the bacterial ileal luminal colonization. Molecular analysis showed that DCA significantly reduced inflammatory mediators of Infγ, Litaf, Il1ß, and Mmp9 mRNA accumulation in ileal tissue. Mechanism studies revealed that C. perfringens induced (P < 0.05) elevated expression of inflammatory mediators of Infγ, Litaf, and Ptgs2 (Cyclooxygenases-2 (COX-2) gene) in chicken splenocytes. Inhibiting the COX signaling by aspirin significantly attenuated INFγ-induced inflammatory response in the splenocytes. Consistent with the in vitro assay, chickens fed 0.12 g/kg aspirin diet protected the birds against NE-induced BW loss, ileal inflammation, and intestinal cell apoptosis. In conclusion, microbial metabolic product DCA prevents NE-induced BW loss and ileal inflammation through attenuating inflammatory response. These novel findings of microbiome protecting birds against NE provide new options on developing next generation antimicrobial alternatives against NE.

11.
Zhongguo Zhong Yao Za Zhi ; 44(14): 2966-2971, 2019 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-31602841

RESUMO

To study the effects of saikosaponin b2( SS-b2) on inflammatory factors and energy metabolism against lipopolysaccharide/galactosamine( LPS/Gal N) induced acute liver injury in mice. Mice were randomly divided into normal group( equal amount of normal saline),model group( 100 g·kg~(-1) LPS and 400 mg·kg~(-1) Gal N),low,medium,high dose group of SS-b2( SS-b25,10,20 mg·kg~(-1)·d-1) and positive control group( dexamethasone,10 mg·kg~(-1)). All of the groups except for the normal group were treated with LPS/Gal N though intraperitoneally injection to establish the acute liver injury model. The organ indexes were calculated. The levels of serum transaminases( ALT and AST) and the activities of ATPase( Na+-K+-ATPase,Ca2+-Mg2+-ATPase) in liver were detected. The activity of tumor necrosis factor-α( TNF-α),interleukin-1ß( IL-1ß) and interleukin-6( IL-6) were determined by the enzyme-linked immunosorbent assay( ELISA). The contents of lactate dehydrogenase( LDH) in liver were determined by micro-enzyme method. HE staining was used to observe the histopathological changes of the liver. Histochemical method was used to investigate the protein expression of liver lactate dehydrogenase-A( LDH-A). The protein expressions of Sirt-6 and NF-κB in the liver were detected by Western blot. According to the results,compared with the model group,there were significant changes in organ indexes in the high-dose group of SS-b2( P<0. 05). The level of ALT,AST,TNF-α,IL-1ß,IL-6 and the activities of LDH in serum of mice with liver injury were significantly reduced in the medium and high dose groups of SS-b2( P<0. 01). With the increase of the concentration of SS-b2,the range of hepatic lesions and the damage in mice decreased. The activities of Na+-K+-ATPase and Ca2+-Mg2+-ATPase in liver of mice were significantly enhanced in each dose group( P<0. 01). The expression of NF-κB in liver tissues was significantly down-regulated in the medium and high dose group( P<0. 01). Meanwhile,the expression of Sirt-6 protein in the liver of mice with acute liver injury was significantly increased in each dose group( P<0. 01).In summary,SS-b2 has a significant protective effect on LPS/Gal N-induced acute liver injury in mice,which may be related to the down-regulation of NF-κB protein expression and up-regulation of Sirt-6 protein expression to improve inflammatory injury and energy metabolism.

12.
Bioresour Technol ; 294: 122188, 2019 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-31569044

RESUMO

In this work, wrapped granular activated carbon (GAC) and acclimated sludge were employed to enhance the efficiency of the dry anaerobic digestion of swine manure in semi-continuous tests. The addition of wrapped GAC increased the volumetric biogas production rate by 10.6%, and the removal efficiencies of TS and VS were enhanced by 5.3% and 6.6%, respectively. The concentration of total volatile fatty acids (TVFA) was 30.3% lower in the GAC reactor, but the total ammonia nitrogen (TAN) content was 15.3% higher. Inoculating with acclimated sludge helped the system survive unfavorable conditions, where the TAN and TVFA contents were around 5,200 mg/L and 8,800 mg/L, respectively, but it failed to improve the biogas production efficiency. The mechanisms that allowed GAC to increase the production of biogas were related to the improved hydrolysis process, enhanced microbial adhesion, the provision of electronic bridges, and enrichment of functional microorganism.

13.
PLoS One ; 14(10): e0222636, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31593573

RESUMO

BACKGROUND: Escherichia coli is currently unable to be reliably differentiated from Shigella species by routine matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) analysis. In the present study, a reliable and rapid identification method was established for Escherichia coli and Shigella species based on a short-term high-lactose culture using MALDI-TOF MS and artificial neural networks (ANN). MATERIALS AND METHODS: The Escherichia coli and Shigella species colonies, treated with (Condition 1)/without (Condition 2) a short-term culture with an in-house developed high-lactose fluid medium, were prepared for MALDI-TOF MS assays. The MS spectra were acquired in linear positive mode, with a mass range from 2000 to 12000 Da and were then compared to discover new biomarkers for identification. Finally, MS spectra data sets 1 and 2, extracted from the two conditions, were used for ANN training to investigate the benefit on bacterial classification produced by the new biomarkers. RESULTS: Twenty-seven characteristic MS peaks from the Escherichia coli and Shigella species were summarized. Seven unreported MS peaks, with m/z 2330.745, m/z 2341.299, m/z 2371.581, m/z 2401.038, m/z 3794.851, m/z 3824.839 and m/z 3852.548, were discovered in only the spectra from the E. coli strains after a short-term high-lactose culture and were identified as belonging to acid shock protein. The prediction accuracies of the ANN models, based on data set 1 and 2, were 97.71±0.16% and 74.39±0.34% (n = 5), with an extremely remarkable difference (p < 0.001), and the areas under the curve of the receiver operating characteristic curve were 0.72 and 0.99, respectively. CONCLUSIONS: In summary, adding a short-term high-lactose culture approach before the analysis enabled a reliable and easy differentiation of Escherichia coli from the Shigella species using MALDI-TOF MS and ANN.

14.
Chem Commun (Camb) ; 2019 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-31596278

RESUMO

Flexible, highly conductive, robust nitrogen (N), sulfur (S) co-doped graphitic hollow carbon fibers (CFs) were directly fabricated by vacuum carbonization of "human hairs". By engineering these cost-effective CFs with polydiacetylene (PDA), a new family of ultrasensitive, reversible electrochromatic fibers that display switchable color transition (blue ⇋ red) upon exposure to current and UV-light stimuli was successfully created.

15.
Medicine (Baltimore) ; 98(39): e17305, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31574858

RESUMO

Until now, the recognition of sodium taurocholate cotransporting polypeptide (NTCP) deficiency has been mainly based on sporadic case reports. It was previously believed to be mildly symptomatic and resulting in mild liver dysfunction. However, to our knowledge, there have been no reports about the histopathologic and ultrastructural pathologic characteristics of the disease. The aim of the study was to analyze the clinical, histopathologic and ultrastructural pathologic characteristics of NTCP deficiency in 13 pediatric patients.From August 2012 to October 2018, this retrospective study conducted in the Department of Pediatrics of Tongji Hospital, China analyzed the data of 13 NTCP deficient patients with an SLC10A1 gene mutation. Except for NTCP deficiency, no other liver diseases were present in the patients, which was determined by both a genetic testing panel for jaundice and by reviewing medical records. The laboratory results, imaging, histopathologic, and ultrastructural pathologic information were recorded for analysis.The serum level of total bile acid was high in all 13 patients. All patients had adequate growth and development. Eight of the patients (8/13) presented with visible jaundice and 12 (12/13) were found to have hyperbilirubinemia. A needle liver biopsy was performed in 11 cases, which revealed slightly chronic inflammation in all 11 patients. One of the patients (1/13) was found to be suffering from gallstones.The data showed that although NTCP deficiency was often asymptomatic, some of the patients showed obvious clinical expressions, such as jaundice. Among the 13 pediatric patients with NTCP deficiency, both the biochemical and histopathologic features were similar to those of mild hepatocellular jaundice. In addition, it was determined that the clinical features in the patient with gallstones may have been caused by NTCP deficiency.


Assuntos
Ácidos e Sais Biliares/sangue , Icterícia , Hepatopatias , Fígado , Transportadores de Ânions Orgânicos Dependentes de Sódio , Simportadores , Desenvolvimento Infantil , Pré-Escolar , China/epidemiologia , Testes Genéticos/métodos , Humanos , Biópsia Guiada por Imagem/métodos , Lactente , Icterícia/diagnóstico , Icterícia/etiologia , Fígado/metabolismo , Fígado/patologia , Hepatopatias/diagnóstico , Hepatopatias/genética , Hepatopatias/fisiopatologia , Hepatopatias/terapia , Testes de Função Hepática/métodos , Glicoproteínas de Membrana/metabolismo , Mutação , Transportadores de Ânions Orgânicos Dependentes de Sódio/deficiência , Transportadores de Ânions Orgânicos Dependentes de Sódio/genética , Pediatria/métodos , Estudos Retrospectivos , Simportadores/deficiência , Simportadores/genética
16.
Mar Drugs ; 17(10)2019 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-31569555

RESUMO

Microbial siderophores are multidentate Fe(III) chelators used by microbes during siderophore-mediated assimilation. They possess high affinity and selectivity for Fe(III). Among them, marine siderophore-mediated microbial iron uptake allows marine microbes to proliferate and survive in the iron-deficient marine environments. Due to their unique iron(III)-chelating properties, delivery system, structural diversity, and therapeutic potential, marine microbial siderophores have great potential for further development of various drug conjugates for antibiotic-resistant bacteria therapy or as a target for inhibiting siderophore virulence factors to develop novel broad-spectrum antibiotics. This review covers siderophores derived from marine microbes.

17.
Complement Ther Clin Pract ; : 101061, 2019 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-31570211

RESUMO

BACKGROUND AND PURPOSE: Balance impairment is the predominant risk factor for falls in stroke survivors. This study examined the effects of body weight support-Tai Chi (BWS-TC) footwork on balance control among stroke survivors with fear of falling (FOF). MATERIALS AND METHODS: Twenty-eight stroke survivors with FOF were randomly allocated to either control or BWS-TC groups. Those in BWS-TC underwent Tai Chi training for 12 weeks. Outcomes were assessed in all participants by evaluation of the limits of stability test, modified clinical test of sensory integration of balance, fall risk index, and Fugl-Meyer assessment of lower limbs at baseline and 12 weeks. RESULTS: The BWS-TC group displayed significant enhancement in dynamic control and vestibular and somatosensory integration. CONCLUSION: BWS-TC may enhance dynamic control and sensory integration of balance and reduce the risk of fall in stroke survivors with FOF.

18.
Nat Genet ; 2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31570888

RESUMO

Rhizoctonia solani is a widely distributed phytopathogen that causes banded leaf and sheath blight in maize and sheath blight in rice. Here, we identified an F-box protein (ZmFBL41) that confers resistance to banded leaf and sheath blight through a genome-wide association study in maize. Rice overexpressing ZmFBL41 showed elevated susceptibility to R. solani. Two amino acid substitutions in this allele prevent its interaction with ZmCAD, which encodes the final enzyme in the monolignol biosynthetic pathway, resulting in the inhibition of ZmCAD degradation and, consequently, the accumulation of lignin and restriction of lesion expansion. Knocking out the ZmCAD-homologous gene OsCAD8B in rice enhanced susceptibility to R. solani. The results reveal a susceptibility mechanism in which R. solani targets the host proteasome to modify the secondary metabolism of the plant cell wall for its invasion. More importantly, it provides an opportunity to generate R. solani-resistant varieties of different plant species.

19.
J Nat Prod ; 2019 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-31599578

RESUMO

The new phthalideisoquinoline hemiacetal alkaloids (2-7) and the known analogues (1 and 8) were isolated from the bulbs of Corydalis decumbens. The new compounds were characterized by analysis of their NMR spectroscopic data, chemical degradation syntheses, X-ray crystallography, and comparison of experimental and calculated ECD data. All the isolates were screened in vitro for inhibitory activity of spontaneous calcium oscillations in primary cultured neocortical neurons. Compounds 1-3 and 5-7 were found to be active in the suppression of spontaneous calcium oscillations with IC50 values of 6.8, 5.6, 11.6, 10.2, 8.3, and 3.1 µM, respectively. It was also observed that the presence of hydroxy, methoxy, and ethoxy groups at the remote stereogenic center C-7' of some isolated phthalideisoquinoline hemiacetal alkaloids could alter the preferred conformation and invert the sign of optical rotation, rather than this resulting from configurational isomerism at C-1 or C-9, and that the 3J1,9 coupling constants of these analogues varied accordingly. For example, compounds 1 and 6 are levorotatory, despite these molecules having the same carbon skeleton and absolute configuration as (+)-egenine. This emphasizes the potential risk of incorrectly assigning absolute configuration based only on observed coupling constants or optical rotation when comparing the data of new compounds with literature values for known analogues, especially within this class of molecules.

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