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A mesonephric-like endometrial adenocarcinoma (ML-EAC) is very rare and has a worse prognosis than other endometrial carcinomas. We describe an ML-EAC and report our endometrial cytological findings. A 76-year-old woman presented with irregular genital bleeding and a uterine mass. Endometrial cytology revealed atypical cylindrical or spindle-shaped cells in the form of small aggregates or solitary cells. The cell aggregates exhibited irregularly stacked papillary structures, small glandular structures, and fenestrated structures. The atypical cells had a nucleus with fine-granular chromatin and a granular cytoplasm, and nuclear grooves and intranuclear pseudo-inclusions were present. Hyaline globules were observed in the glandular lumens and in the background. The presumptive histological type was an adenocarcinoma, but the cytological features were different from those of an endometrioid carcinoma. A histological examination of the endometrial biopsy revealed an adenocarcinoma, and a simple hysterectomy was performed. A grayish-white elevated mass measuring 90 mm × 70 mm × 40 mm was observed on the uterine corpus in the hysterectomy specimen. Histologically, the tumor proliferated as complex tubular structures containing eosinophilic colloid-like materials and trabecular structures. The tumor cells were diffuse and positive for GATA-3 and partially positive for thyroid transcription factor-1. Estrogen and progesterone receptors were negative. An ML-EAC was diagnosed. The tumor was invasive and extended beyond one-half of the muscle layer with a high degree of vascular invasion. In conclusion, we need to focus on the various shapes of the cell aggregate, nuclear grooves, and intranuclear pseudo-inclusions of tumor cells to distinguish an ML-EAC from other endometrial carcinomas in endometrial cytology.
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Adenocarcinoma , Neoplasias Endometriales , Humanos , Femenino , Neoplasias Endometriales/patología , Neoplasias Endometriales/diagnóstico , Anciano , Adenocarcinoma/patología , Adenocarcinoma/diagnóstico , Endometrio/patologíaRESUMEN
Six undescribed chlorinated sesquiterpene carbamates, aaptocarbamates A-F, and a chlorinated tris-norsesquiterpene carbamate, aaptocarbamate G, were isolated from the marine sponge Aaptos sp. collected in Indonesia. Aaptocarbamates D-F and G possess tetrahydrofurans and a tetrahydrofuranone, respectively. The relative configurations of the tetrahydrofuran units were determined by the NOE correlations and DFT-based calculation of the 13C chemical shifts. This is the first time that chlorinated terpene carbamates have been reported from natural sources. Various aaptamine derivatives have been reported from the Aaptos sponges so far, the isolation of chlorinated terpene carbamates is very rare. Aaptocarbamates A, B, and D showed 60% inhibition of the RANKL-induced formation of multinucleated osteoclasts in RAW264 macrophages at 20 µM.
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Poríferos , Terpenos , Animales , Terpenos/farmacología , Carbamatos/farmacologíaRESUMEN
BACKGROUND: It is widely known that there is low striatal 123 I-2ß-Carbomethoxy-3ß-(4-iodophenyl)-N-(3- fluoropropyl) nortropane (123 I-FP-CIT) dopamine transporter single photon emission tomography (DaT-SPECT) uptake in patients with dementia with Lewy bodies (DLB). No studies to date have analyzed the association between longitudinal changes of clinical features and DaT uptake in patients with Parkinson syndrome, particularly those with DLB. The aim of this study was to investigate the association between the longitudinal changes in DaT uptake and the severity of parkinsonism and cognitive function in DLB patients. METHODS: A total of 35 outpatients with probable DLB who underwent DaT-SPECT twice (at the initial examination and the follow-up period) in the Memory Disorder Clinic at the Department of Geriatric Medicine, Tokyo Medical University, were enrolled in this study between April 2014 and September 2020. The correlation between annual changes in DaT uptake and clinical features (cognitive function decline and parkinsonism) of the patients was analyzed. RESULTS: A significant correlation was detected between annual changes in parkinsonism symptom severity and DaT uptake in the left posterior putamen (r = -0.39, P = 0.03), and between Mini-Mental State Examination scores and DaT uptake in all regions except the right posterior putamen (P < 0.05) in patients with DLB. CONCLUSIONS: Our results suggested that the pathway from the ventrolateral tier of the substantia nigra to the putamen might be more crucial for motor function than other pathways, not only in Parkinson's disease but also in DLB.
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Enfermedad por Cuerpos de Lewy , Enfermedad de Parkinson , Anciano , Humanos , Cuerpo Estriado/diagnóstico por imagen , Cuerpo Estriado/metabolismo , Proteínas de Transporte de Dopamina a través de la Membrana Plasmática/metabolismo , Enfermedad por Cuerpos de Lewy/diagnóstico , Enfermedad de Parkinson/diagnóstico por imagen , Tomografía Computarizada de Emisión de Fotón Único/métodosAsunto(s)
Carcinoma Neuroendocrino , Neoplasias Pancreáticas , Humanos , Abdomen/patología , Ascitis/diagnóstico por imagen , Carcinoma Neuroendocrino/diagnóstico , Carcinoma Neuroendocrino/patología , Biopsia por Aspiración con Aguja Fina Guiada por Ultrasonido Endoscópico , Vesícula Biliar/diagnóstico por imagen , Vesícula Biliar/patología , Neoplasias Pancreáticas/patologíaRESUMEN
Tirabrutinib is a highly selective Bruton's tyrosine kinase (BTK) inhibitor used to treat hematological malignancies. We analyzed the anti-tumor mechanism of tirabrutinib using phosphoproteomic and transcriptomic methods. It is important to check the drug's selectivity against off-target proteins to understand the anti-tumor mechanism based on the on-target drug effect. Tirabrutinib's selectivity was evaluated by biochemical kinase profiling assays, peripheral blood mononuclear cell stimulation assays, and the BioMAP system. Next, in vitro and in vivo analyses of the anti-tumor mechanisms were conducted in activated B-cell-like diffuse large B-cell lymphoma (ABC-DLBCL) cells followed by phosphoproteomic and transcriptomic analyses. In vitro kinase assays showed that, compared with ibrutinib, tirabrutinib and other second-generation BTK inhibitors demonstrated a highly selective kinase profile. Data from in vitro cellular systems showed that tirabrutinib selectively affected B-cells. Tirabrutinib inhibited the cell growth of both TMD8 and U-2932 cells in correlation with the inhibition of BTK autophosphorylation. Phosphoproteomic analysis revealed the downregulation of ERK and AKT pathways in TMD8. In the TMD8 subcutaneous xenograft model, tirabrutinib showed a dose-dependent anti-tumor effect. Transcriptomic analysis indicated that IRF4 gene expression signatures had decreased in the tirabrutinib groups. In conclusion, tirabrutinib exerted an anti-tumor effect by regulating multiple BTK downstream signaling proteins, such as NF-κB, AKT, and ERK, in ABC-DLBCL.
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Linfoma de Células B Grandes Difuso , Humanos , Agammaglobulinemia Tirosina Quinasa , Transcriptoma , Proteínas Proto-Oncogénicas c-akt/metabolismo , Leucocitos Mononucleares/metabolismo , Linfoma de Células B Grandes Difuso/patología , Inhibidores de Proteínas Quinasas/farmacologíaRESUMEN
Cyclodextran (CI) is a cyclic oligosaccharide in which d-glucose forms a ring structure by α-1,6 glycoside linkage and forms an inclusion complex with various guest molecules. In this study, we conducted quantum chemical calculations and molecular dynamics (MD) simulations to analyze the molecular interaction mechanism of CI with a guest molecule. Calculations of cyclodextrin (CD), in which d-glucose forms a ring structure by α-1,4 glycoside linkage, were also performed for comparison. Here, coenzyme Q10 (CoQ10), a promising molecule for industrial application with CI, was chosen as a guest molecule. Our MD simulation demonstrated that the molecular fluctuation was similarly large for both CI and CD when CoQ10 was absent. In the case that CoQ10 exists, the CD was found to form a rigid one-by-one inclusion structure, while CI does not. Additional simulations including multiple CI-8s indicated the possibility that an inclusion structure is maintained by the existence of other CI-8s.
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Ciclodextrinas , Ciclodextrinas/química , Simulación de Dinámica Molecular , Glicósidos , GlucosaRESUMEN
Hereditary ATTR amyloidosis is caused by the point mutation in serum protein transthyretin (TTR) that destabilizes its tetrameric structure to dissociate into monomer. The monomers form amyloid fibrils, which are deposited in peripheral nerves and organs, resulting in dysfunction. Therefore, a drug that dissolves amyloid after it has formed, termed amyloid disruptor, is needed as a new therapeutic drug. Here, we first established a high throughput screening system to find TTR interactors from the LOPAC1280 compound library. Among the hit compounds, thioflavin T-based post-treatment assay determined lead compounds for TTR amyloid disruptors, NSC95397 and Gossypol, designated as B and R, respectively. Because these compounds have naphthoquinone-naphthalene structures, we tested 100 naphthoquinone derivatives, and found 10 candidate compounds that disrupted TTR amyloid. Furthermore, to determine whether these 10 compounds are selective for TTR amyloid, we evaluated them against beta-amyloid (Aß1-42). We found two compounds that were selective for TTR and did not disrupt Aß-derived amyloid. Therefore, we succeeded in identifying TTR-selective amyloid disruptors, and demonstrated that naphthoquinone compounds are useful structures as amyloid disruptors. These findings contribute to the on-going efforts to discover new therapeutic tools for TTR amyloidosis.
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Neuropatías Amiloides Familiares , Amiloidosis , Naftoquinonas , Humanos , Prealbúmina/química , Prealbúmina/genética , Prealbúmina/metabolismo , Amiloide/metabolismo , Amiloide/uso terapéutico , Amiloidosis/metabolismo , Péptidos beta-Amiloides , Naftoquinonas/farmacología , Neuropatías Amiloides Familiares/tratamiento farmacológico , Neuropatías Amiloides Familiares/metabolismoRESUMEN
Antiosteoclastogenic-guided screening was conducted with 120 extracts of the medicinal plants collected in Egypt that led to the selection of Artemisia judaica L. (Asteraceae). Three undescribed davanone-related terpenoids, arteperoxides A-C, were isolated from the extract with two known derivatives, hydroxydavanone and davana acid. Structural analysis revealed that arteperoxides A-C were tris-normonoterpene-sesquiterpene conjugates with peroxide bridges. Although davanone derivatives with peroxides, such as a hydroperoxyl and peroxyhemiketal groups, have been isolated from Artemisia species, arteperoxides A-C are the first variations observed to contain peroxide bridges between two terpene-derived units. The absolute configurations of arteperoxides A and B were studied based on their spectroscopic data compared with those of the semisynthetic analogs that have ether linkages. The natural and synthetic compounds were tested for the antiosteoclastogenic activity, and arteperoxide C and hydroxydavanone were more potent than other compounds at 20 µM.
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Artemisia , Plantas Medicinales , Sesquiterpenos , Artemisia/química , Peróxidos , Sesquiterpenos/farmacología , Sesquiterpenos/química , Terpenos , Extractos Vegetales/farmacología , Extractos Vegetales/químicaRESUMEN
Oral frailty associated with oral hypokinesia may cause dementia. Functional near-infrared spectroscopy (fNIRS) can be used while the participants are in seating position with few restrictions. Thus, it is useful for assessing brain function, particularly oral motor activity. However, methods for identifying oral motor cortex (OMC) activation via the scalp have not been established. The current study aimed to detect OMC activation, an indicator of activity phase ratio (APR), which reflects increased oxygen consumption (0 < [deoxyhemoglobin (ΔDeoxyHb) or 0 < {[ΔDeoxyHb- oxyhemoglobin (ΔOxyHb)/â2]}, via fNIRS to accurately identify local brain activity. The APR, calculated via zero-set vector analysis, is a novel index for quantifying brain function both temporally and spatially at rest and during tasks. In total, 14 healthy participants performed bite tasks for 3 s per side for 10 times while in the sitting position. Then, time-series data on concentration changes in ΔOxyHb and ΔDeoxyHb were obtained via fNIRS. The anatomical location of the OMC was determined using a pooled data set of three-dimensional magnetic resonance images collected in advance from 40 healthy adults. In the zero-set vector analysis, the average change in ΔOxyHb and ΔDeoxyHb concentrations was utilized to calculate the APR percentage in 140 trials. The significant regions (z-score of ≥2.0) of the APR and ΔOxyHb in the task were compared. During the bite task, the APR significantly increased within the estimated OMC region (56-84 mm lateral to Cz and 4-20 mm anterior to Cz) in both the right and left hemispheres. By contrast, the ΔOxyHb concentrations increased on the bite side alone beyond the OMC region. The mean APR at rest for 2 s before the task showed 59.5%-62.2% in the left and right OMCs. The average APR for 3 s during the task showed 75.3% for the left OMC and 75.7% for the right OMC during the left bite task, and 65.9% for the left OMC and 80.9% for the right OMC during the right bite task. Interestingly, the average increase in APR for the left and right OMCs for the left bite task and the right bite task was 13.9% and 13.7%, respectively, showing almost a close match. The time course of the APR was more limited to the bite task segment than that of ΔOxyHb or ΔDexyHb concentration, and it increased in the OMC. Hence, the APR can quantitatively monitor both the resting and active states of the OMC in the left and right hemispheres. Using the zero-set vector-based fNIRS, the APR can be a valid indicator of oral motor function and bite force.
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AIM: Depressive symptoms are one of the most common neuropsychiatric symptoms in patients with mild cognitive impairment (MCI) and Alzheimer's disease (AD), although the pathophysiologies of the depressive symptoms that occur in these diseases have not been elucidated to date. In this study, we therefore investigated the associations between depressive symptoms and cognitive performance, white matter abnormalities, and regional cerebral blood flow (rCBF) in amnestic MCI patients. METHODS: Thirty-eight patients with amnestic MCI were analyzed. The volumes of periventricular hyperintensities (PVH) and deep white matter hyperintensities (DWMH) were measured on T2-fluid-attenuated inversion recovery magnetic resonance imaging using the imaging software 3D-slicer. Associations between the Geriatric Depression Scale (GDS) score and other neuropsychological test scores on the one hand and the PVH and DWMH volumes on the other were analyzed. Voxel-wise correlations of rCBF with GDS score, after controlling for the effects of age, were investigated using SPM8 software. RESULTS: Significant correlations were identified between GDS score, Trail Making Test B and apathy scale scores on the one hand and PVH volume on the other. A significant negative association between GDS score and rCBF was identified in the right dominant bilateral dorsolateral prefrontal cortex (DLPFC). CONCLUSIONS: Depressive symptoms are significantly associated with PVH volume in MCI patients. The rCBF of the DLPFC was significantly associated with depressive symptoms, suggesting that this area might be closely involved in the pathogenesis of the depressive symptoms observed in MCI patients. Geriatr Gerontol Int 2022; 22: 846-850.
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Enfermedad de Alzheimer , Disfunción Cognitiva , Leucoaraiosis , Sustancia Blanca , Anciano , Enfermedad de Alzheimer/psicología , Circulación Cerebrovascular/fisiología , Disfunción Cognitiva/psicología , Depresión , Humanos , Imagen por Resonancia Magnética/métodos , Pruebas Neuropsicológicas , Sustancia Blanca/diagnóstico por imagen , Sustancia Blanca/patologíaRESUMEN
Skeletal muscle unloading leads to muscle atrophy. Ribosome synthesis has been implicated as an important skeletal muscle mass regulator owing to its translational capacity. Muscle unloading induces a reduction in ribosome synthesis and content, with muscle atrophy. Percutaneous electrical muscle stimulation (pEMS)-induced muscle contraction is widely used in clinics to improve muscle mass. However, its efficacy in rescuing the reduction in ribosomal synthesis has not been addressed thus far. We examined the effects of daily pEMS treatment on ribosome synthesis and content during mouse hindlimb unloading. Male C57BL/6J mice were randomly assigned to sedentary (SED) and hindlimb unloading by pelvic suspension (HU) groups. Muscle contraction was triggered by pEMS treatment of the right gastrocnemius muscle of a subset of the HU group (HU + pEMS). Hindlimb unloading for 6 days significantly lowered 28S rRNA, rpL10, and rpS3 expression, which was rescued by daily pEMS treatment. The protein expression of phospho-p70S6K and UBF was significantly higher in the HU + pEMS than in the HU group. The mRNA expression of ribophagy receptor Nufip1 increased in both the HU and HU + pEMS groups. Protein light chain 3 (LC3)-II expression and the LC3-II/LC3-I ratio were increased by HU, but pEMS attenuated this increase. Our findings indicate that during HU, daily pEMS treatment prevents the reduction in the levels of some proteins associated with ribosome synthesis. In addition, the HU-induced activation of ribosome degradation may be attenuated. These data provide insights into ribosome content regulation and the mechanism of attenuation of muscle atrophy by pEMS treatment during muscle disuse.NEW & NOTEWORTHY Muscle inactivity reduces ribosome synthesis and content during atrophy. Whether percutaneous electrical muscle stimulation (pEMS)-induced muscle contraction rescues the ribosome synthesis and content during muscle unloading is unclear. Using a mouse hindlimb-unloading model with pelvic suspension, we provide evidence that daily pEMS-induced muscle contraction during hindlimb unloading rescues the reduction in the expression of some ribosome synthesis-related proteins and ribosome content in the gastrocnemius muscle.
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Suspensión Trasera , Proteínas Quinasas S6 Ribosómicas 70-kDa , Animales , Estimulación Eléctrica , Miembro Posterior/metabolismo , Suspensión Trasera/fisiología , Masculino , Ratones , Ratones Endogámicos C57BL , Contracción Muscular , Músculo Esquelético/fisiología , Atrofia Muscular/metabolismo , ARN Mensajero/metabolismo , ARN Ribosómico/metabolismo , ARN Ribosómico 28S/metabolismo , Proteínas Quinasas S6 Ribosómicas 70-kDa/metabolismo , Ribosomas/metabolismoRESUMEN
Natural products exhibit structural diversity, and biologically active natural products with unprecedented molecular skeletons can potentially be isolated from natural resources in the future. Although it has often been difficult to determine the structures and configurations of new compounds that do not resemble known compounds, the determination of the chemical structures, including the absolute stereo configuration, is very important in drug discovery research. In our efforts to find new bioactive natural products, we have identified novel compounds such as the ubiquitin-proteasome system inhibitors and osteoclast differentiation inhibitors. Various natural products, mixtures of stereoisomers of natural products, and compounds with novel skeletal structures were studied. In cases where it was difficult to determine the structures by NMR spectroscopy, we could successfully determine the chemical structures by computational chemistry. This review presents the results of structural analysis obtained using computational methods for several natural products that we have recently isolated.
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Productos Biológicos , Productos Biológicos/química , Dicroismo Circular , Espectroscopía de Resonancia Magnética , Estructura Molecular , EstereoisomerismoRESUMEN
Three new diterpenes, stellejasmins A (1) and B (2) and 12-O-benzoylphorbol-13-heptanoate (3), were isolated from the roots of Stellera chamaejasme L. The structures of 1-3 were elucidated by extensive NMR and mass spectroscopic analyses. Compounds 1 and 2 are the first derivatives containing a hydroxy group at C-2 in the family of daphnane and tigliane diterpenes. The presence of a chlorine atom in 1 is unique in the plant metabolite. Compound 3 has an odd-number acyl group, which is biosynthetically notable. Human immunodeficiency virus (HIV) LTR-driven transcription activity was tested with 1-3 and 17 known diterpenes isolated from S. chamaejasme L. and Wikstroemia retusa A.Gray. Among these, gnidimacrin (4), stelleralide A (5), and wikstroelide A (20) were highly potent, with EC50 values of 0.14, 0.33, and 0.39 nM, respectively. The structure-activity relationship (SAR) was investigated using 20 natural and eight synthetic diterpenes. This is the first SAR study on natural daphnane and tigliane diterpenes.
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Fármacos Anti-VIH/síntesis química , Fármacos Anti-VIH/farmacología , Diterpenos/síntesis química , Diterpenos/farmacología , VIH/efectos de los fármacos , Forboles/química , Latencia del Virus/efectos de los fármacos , Diterpenos/química , Modelos Moleculares , Simulación del Acoplamiento Molecular , Forboles/farmacología , Extractos Vegetales/química , Extractos Vegetales/farmacología , Raíces de Plantas/química , Relación Estructura-Actividad , Thymelaeaceae/química , Wikstroemia/químicaRESUMEN
The ubiquitin-proteasome system (UPS) regulates selective protein degradation to maintain protein homeostasis. Small molecules that inhibit the UPS-dependent protein degradation are promising anti-tumor agents. We report a cell-based luminescent assay using HeLa cells expressing luciferase-fused oxygen-dependent destruction domain (ODD) of hypoxia-inducible factor 1 α (HIF-1 α). ODD is degraded by the UPS and this assay system can aid in the identification of natural products that inhibit either process of the UPS, including ubiquitination/deubiquitination and proteasomal degradation. This reporter assay can exclude the influences of coloring or fluorescent compounds in extracts, thereby leading to effective high-throughput processing. The screening of 15,025 extracts of natural sources identified the culture extract of the fungus Remotididymella sp. (18F02908). Bioassay-guided isolation yielded two new polyketides, mellains A (1) and B (2), together with leptosphaerodione (3) and its acetone adduct 4. Compound 1 was revealed to have an unprecedented benzo[g]isoquinoline-8,10-dione skeleton. Evaluation of the biological activities demonstrated that these polyketides inhibit the proteasomal proteolysis. This is the first report of the identification of proteasome inhibitors from natural sources using a cell-based reporter assay targeting UPS inhibitors.
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Ascomicetos/química , Productos Biológicos/farmacología , Complejo de la Endopetidasa Proteasomal/metabolismo , Inhibidores de Proteasoma/farmacología , Productos Biológicos/química , Productos Biológicos/aislamiento & purificación , Relación Dosis-Respuesta a Droga , Evaluación Preclínica de Medicamentos , Células HeLa , Humanos , Estructura Molecular , Inhibidores de Proteasoma/química , Inhibidores de Proteasoma/aislamiento & purificación , Relación Estructura-ActividadRESUMEN
A simple methylenedioxy dibromoindole alkaloid, amakusamine (1), was isolated from a marine sponge of the genus Psammocinia, and its structure was determined from spectroscopic data, time-dependent density-functional theory calculations, and synthesis. Compound 1 inhibited the receptor activator of nuclear factor-κB ligand (RANKL)-induced formation of multinuclear osteoclasts with an IC50 value of 10.5 µM in RAW264 cells. The structure-activity relationship of 1 was also investigated with synthetic derivatives.
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Alcaloides/farmacología , Osteoclastos/efectos de los fármacos , Poríferos/química , Ligando RANK/antagonistas & inhibidores , Animales , Japón , Ratones , Estructura Molecular , Células RAW 264.7 , Relación Estructura-ActividadRESUMEN
Fifteen new isopimarane-type diterpenes, taichunins E-S (1-15), and a new 20-nor-isopimarane, taichunin T (16), together with four known compounds were isolated from Aspergillus taichungensis (IBT 19404). The structures of these new compounds were determined by NMR and mass spectroscopy, and their absolute configurations were analyzed by NOESY and TDDFT calculations of ECD spectra. Taichunins G, K, and N (3, 7, and 10) completely inhibited the receptor activator of nuclear factor-κB ligand (RANKL)-induced formation of multinuclear osteoclasts in RAW264 cells at 5 µM, with 3 showing 92% inhibition at a concentration of 0.2 µM.
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Abietanos/farmacología , Aspergillus/química , Osteoclastos/efectos de los fármacos , Ligando RANK , Abietanos/aislamiento & purificación , Animales , Productos Biológicos/aislamiento & purificación , Productos Biológicos/farmacología , Ratones , Estructura Molecular , Células RAW 264.7 , TaiwánAsunto(s)
Biomarcadores de Tumor/metabolismo , Linfadenopatía Inmunoblástica/patología , Linfoma de Células T/patología , Derrame Pleural/patología , Anciano , Femenino , Humanos , Linfadenopatía Inmunoblástica/metabolismo , Ganglios Linfáticos/metabolismo , Ganglios Linfáticos/patología , Linfoma de Células T/metabolismo , Derrame Pleural/metabolismoRESUMEN
One of the major environmental stress factors that affect root growth is salinity. Arabidopsis thaliana, a glycophyte, shows halotropism, whereby it alters the direction of root growth in a non-gravitropic pattern to evade high soil salinity. Asymmetric auxin distribution regulated by the relocation of auxin-efflux carrier proteins is a key cellular event in the halotropic response. However, there are no reports of halotropism in halophytes. Here, we investigated root growth traits in Mesembryanthemum crystallinum (ice plant), under high salinity conditions. We hypothesized that ice plant roots would show halotropic responses different from those of Arabidopsis Notably, similar to halotropism observed in Arabidopsis, ice plant roots showed continuous root bending under salinity stress. However, the root elongation rate did not change in ice plants. Expression analyses of several genes revealed that auxin transport might be partially involved in ice plant halotropism. This study enhances our understanding of halophyte root adaptation to high salinity stress.
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Mesembryanthemum/fisiología , Fenómenos Fisiológicos de las Plantas , Raíces de Plantas/fisiología , Tolerancia a la Sal , Plantas Tolerantes a la Sal , Plantones/crecimiento & desarrollo , Plantones/fisiología , Regulación de la Expresión Génica de las Plantas , Ácidos Indolacéticos/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Estrés Salino , Cloruro de SodioRESUMEN
Fungal bicyclo[2.2.2]diazaoctane indole alkaloids represent an important family of natural products with a wide-spectrum of biological activities. Although biomimetic total syntheses of representative compounds have been reported, the details of their biogenesis, especially the mechanisms for assembly of diastereomerically distinct and enantiomerically antipodal metabolites, have remained largely uncharacterized. Brevianamide A represents a basic form of the sub-family bearing a dioxopiperazine core and a rare 3-spiro-ψ-indoxyl skeleton. Here, we identified the Brevianamide A biosynthetic gene cluster from Penicillium brevicompactum NRRL 864 and elucidated the metabolic pathway. BvnE was revealed to be an essential isomerase/semi-pinacolase that specifies selective production of the natural product. Structural elucidation, molecular modeling, and mutational analysis of BvnE, and quantum chemical calculations provided mechanistic insights into the diastereoselective formation of the 3-spiro-ψ-indoxyl moiety in Brevianamide A. This occurs through a BvnE-controlled semi-pinacol rearrangement and a subsequent spontaneous intramolecular [4+2] hetero-Diels-Alder cycloaddition.