RESUMEN
The quality of light is an important abiotic factor that affects the growth and development of green plants. Ultraviolet, red, blue, and far-red light all have demonstrated roles in regulating green plant growth and development, as well as light morphogenesis. However, the mechanism underlying photosynthetic organism responses to green light throughout the life of them are not clear. In this study, we exposed the unicellular green alga Chlamydomonas reinhardtii to green light and analyzed the dynamics of transcriptome changes. Based on the whole transcriptome data from C. reinhardtii, a total of 9974 differentially expressed genes (DEGs) were identified under green light. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses indicated that these DEGs were mainly related to "carboxylic acid metabolic process," "enzyme activity," "carbon metabolism," and "photosynthesis and other processes." At the same time, 253 differentially expressed long non-coding RNAs (DELs) were characterized as green light responsive. We also made a detailed analysis of the responses of photosynthesis- and pigment synthesis-related genes in C. reinhardtii to green light and found that these genes exhibited obvious dynamic expression. Lastly, we constructed a co-expression regulatory network, comprising 49 long non-coding RNAs (lncRNAs) and 20 photosynthesis and pigment related genes, of which 9 mRNAs were also the predicted trans/cis-targets of 8 lncRNAs, these results suggested that lncRNAs may affect the expression of mRNAs related to photosynthesis and pigment synthesis. Our findings give a preliminary explanation of the response mechanism of C. reinhardtii to green light at the transcriptional level.
Asunto(s)
Chlamydomonas reinhardtii , Luz Verde , Fotosíntesis , ARN Largo no Codificante , Chlamydomonas reinhardtii/genética , Chlamydomonas reinhardtii/metabolismo , Chlamydomonas reinhardtii/efectos de la radiación , Perfilación de la Expresión Génica , Regulación de la Expresión Génica de las Plantas , Ontología de Genes , Redes Reguladoras de Genes , Fotosíntesis/genética , Pigmentos Biológicos/metabolismo , ARN Largo no Codificante/genética , ARN Largo no Codificante/metabolismo , TranscriptomaRESUMEN
Understanding selectivity mechanisms of inhibitors towards highly homologous proteins is of paramount importance in the design of selective candidates. Human aldo-keto reductases (AKRs) pertain to a superfamily of monomeric oxidoreductases, which serve as NADPH-dependent cytosolic enzymes to catalyze the reduction of carbonyl groups to primary and secondary alcohols using electrons from NADPH. Among AKRs, AKR1B1 is emerging as a promising target for cancer treatment and diabetes, despite its high structural similarity with AKR1B10, which leads to severe adverse events. Therefore, it is crucial to understand the selectivity mechanisms of AKR1B1 and AKR1B10 to discover safe anticancer candidates with optimal therapeutic efficacy. In this study, multiple computational strategies, including sequence alignment, structural comparison, Protein Contacts Atlas analysis, molecular docking, molecular dynamics simulation, MM-GBSA calculation, alanine scanning mutagenesis and pharmacophore modeling analysis were employed to comprehensively understand the selectivity mechanisms of AKR1B1/10 inhibition based on selective inhibitor lidorestat and HAHE. This study would provide substantial evidence in the design of potent and highly selective AKR1B1/10 inhibitors in future.
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Inhibidores Enzimáticos , Simulación de Dinámica Molecular , Humanos , Simulación del Acoplamiento Molecular , NADP/metabolismo , Aldo-Ceto Reductasas/metabolismo , Inhibidores Enzimáticos/farmacología , Aldehído Reductasa/metabolismoRESUMEN
In higher plants, the PSI core complex is associated with light-harvesting complex I (LHCI), forming the PSI-LHCI super-complex. In vascular plants, four major antenna proteins (LHCA1-4) are assembled in the order of LHCA1, LHCA4, LHCA2, and LHCA3 into a crescent-shaped LHCI, while LHCA5 and LHCA6 are minor antenna proteins. By contrast, in moss and green algae, LHCA5 or LHCA5-like protein functions as one of the major antenna proteins by residing at the second site of LHCI. In order to learn the effect of binding different LHCA proteins, i.e. LHCA4 or LHCA5, within the PSI-LHCI super-complex on photosynthetic properties of plants, we constructed LHCA5 overexpression plants with a wild type (WT) background and an lhca4 mutant background in Arabidopsis thaliana. The results showed that: (i) there are little difference in phenotype, pigment composition and chlorophyll fluorescence parameters between the transgenic Arabidopsis and their corresponding background materials; (ii) in spite of a small amount of LHCA5, the LHCA5-included PSI-LHCI super-complex can be obtained by extracting samples incubated with anti-FLAG M2 Affinity Gel, in which LHCA5 is found to substitute for LHCA4 as analyzed by immunoblotting analysis; (iii) the replacement of LHCA4 with LHCA5 within PSI-LHCI super-complex leads to a blue shift in low temperature fluorescence emission, suggesting a decrease in far-red absorbance. These results provide new clues for understanding the position and function of LHCA4 and LHCA5 during the evolution of green plants from aquatic to terrestrial lifestyles.
Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Fluorescencia , Complejos de Proteína Captadores de Luz/química , Complejos de Proteína Captadores de Luz/genética , Complejos de Proteína Captadores de Luz/metabolismo , Complejo de Proteína del Fotosistema I/químicaRESUMEN
The family Filoviridae comprises many notorious viruses, such as Ebola virus (EBOV) and Marburg virus (MARV), that can infect humans and nonhuman primates. Lloviu virus (LLOV), a less well studied filovirus, is considered a potential pathogen for humans. The VP30 C-terminal domain (CTD) of these filoviruses exhibits nucleoprotein (NP) binding and plays an essential role in viral transcription, replication and assembly. In this study, we confirmed the interactions between LLOV VP30 CTD and its NP fragment, and also determined the crystal structure of the chimeric dimeric LLOV NP-VP30 CTD at 2.50 Å resolution. The structure is highly conserved across the family Filoviridae. While in the dimer structure, only one VP30 CTD binds the NP fragment, which indicates that the interaction between LLOV VP30 CTD and NP is not strong. Our work provides a preliminary model to investigate the interactions between LLOV VP30 and NP and suggests a potential target for anti-filovirus drug development.
Asunto(s)
Ebolavirus , Nucleoproteínas , Animales , Nucleoproteínas/químicaRESUMEN
Odorant-binding proteins (OBPs) play essential roles in lepidopteran insects' perception of host volatiles by binding and transporting hydrophobic ligands. The yellow peach moth (YPM), Conogethes punctiferalis (Guenée), is a serious agricultural pest, with broad host range and cryptic feeding habits. However, few studies about YPM perceiving pheromones and host plant odorants have been reported. In this study, four OBP genes (CpunOBP8, CpunOBP9, CpunABP, and CpunGOBP2) were cloned from the antennae of YPM. The recombinant proteins were expressed and purified by prokaryotic expression system, with their binding affinities to 26 ligands being tested. Four CpunOBPs all had six conserved cysteine residues, which were typical structural characteristics of classical OBPs. The fluorescence competitive binding assay indicated that CpunOBP8 and CpunABP could not only exhibit high binding affinities to female sex pheromones, but also to host plant odorants. For example, CpunOBP8 bound strongly with cis-10-hexadecenal, hexadecanal, and so forth, whereas CpunABP bound with cis-10-hexadecenal, camphene, and 3-carene. Comparatively, CpunOBP9 and CpunGOBP2 could only bind with host plant odorants, with CpunOBP9 binding strongly to 3-methyl-1-butanol, hexyl acetate, and so forth, while CpunGOBP2 displaying the widest binding spectra and correlating with 3-carene, pentyl acetate, and so forth. The results indicated that on the one hand, each of the four CpunOBPs had its specific binding spectra when binding and transporting olfactory ligands; on the other hand, the same ligand might be bound to more than one CpunOBPs, which would provide information for the potential application of semiochemicals in controlling YPM.
Asunto(s)
Mariposas Nocturnas , Receptores Odorantes , Atractivos Sexuales , Animales , Proteínas de Insectos , Ligandos , Odorantes , FeromonasRESUMEN
Plant-associated microbes have been reported as important but overlooked drivers of plant-herbivorous insect interactions. Influence of plant-associated microbes on plant-insect interactions is diverse, including beneficial, detrimental, and neutral. Here, we determined the effects of three Penicillium fungi, including Penicillium citrinum, Penicillium sumatrense, and Penicillium digitatum, on the oviposition selection and behavior of the yellow peach moth (YPM), Conogethes punctiferalis (Guenée). Compared with fungi noninfected apples (NIA), mechanically damaged apples (MDA), and P. citrinum in potato dextrose agar medium (PC), the oviposition selection and four-arm olfactometer experiments both showed that mated YPM females preferred to P. citrinum-infected apples (PCA). For P. sumatrense or P. digitatum, we also found that mated YPM females preferred to P. sumatrense-infected apples (PSA) or P. digitatum-infected apples (PDA), respectively. Among three Penicillium fungi-infected apples, the selection rates including oviposition and olfactometer behavior of mated YPM females on PDA were both higher than those on PSA and PCA. Further analyses of host plant volatile organic compounds (VOCs) by GC-MS showed that the absolute contents of ethyl hexanoate and (Z, E)-α-farnesene in PCA, PSA, and PDA were all higher than those in NIA, and a total of 16 novel VOCs were detected in fungi-infected apples (PCA, PSA, and PDA), indicating that fungi infection changed the components and proportions of apple VOCs. Taken together, three Penicillium fungi play significant roles in mediating the host selection of YPMs via altering the emissions of VOCs. These findings will be beneficial for developing formulations for field trapping of YPMs in the future.
Asunto(s)
Malus , Mariposas Nocturnas , Penicillium , Prunus persica , Compuestos Orgánicos Volátiles , Animales , Femenino , Frutas/microbiología , Malus/microbiología , Mariposas Nocturnas/fisiología , Compuestos Orgánicos Volátiles/farmacologíaRESUMEN
Photosystem I (PSI) is one of the two photosystems present in oxygenic photosynthetic organisms and functions to harvest and convert light energy into chemical energy in photosynthesis. In eukaryotic algae and higher plants, PSI consists of a core surrounded by variable species and numbers of light-harvesting complex (LHC)I proteins, forming a PSI-LHCI supercomplex. Here, we report cryo-EM structures of PSI-LHCR from the red alga Cyanidioschyzon merolae in two forms, one with three Lhcr subunits attached to the side, similar to that of higher plants, and the other with two additional Lhcr subunits attached to the opposite side, indicating an ancient form of PSI-LHCI. Furthermore, the red algal PSI core showed features of both cyanobacterial and higher plant PSI, suggesting an intermediate type during evolution from prokaryotes to eukaryotes. The structure of PsaO, existing in eukaryotic organisms, was identified in the PSI core and binds three chlorophylls a and may be important in harvesting energy and in mediating energy transfer from LHCII to the PSI core under state-2 conditions. Individual attaching sites of LHCRs with the core subunits were identified, and each Lhcr was found to contain 11 to 13 chlorophylls a and 5 zeaxanthins, which are apparently different from those of LHCs in plant PSI-LHCI. Together, our results reveal unique energy transfer pathways different from those of higher plant PSI-LHCI, its adaptation to the changing environment, and the possible changes of PSI-LHCI during evolution from prokaryotes to eukaryotes.
Asunto(s)
Complejos de Proteína Captadores de Luz/ultraestructura , Complejo de Proteína del Fotosistema I/ultraestructura , Rhodophyta/enzimología , Microscopía por Crioelectrón/métodos , Estructura Cuaternaria de Proteína , Rhodophyta/ultraestructuraRESUMEN
INTRODUCTION: The expression levels of signal transducer and activator of transcription 3 (STAT3) protein and Fascin-1 were inhibited using the STAT3 inhibitor BP-1-102 and RNA interference, respectively, to investigate the expression of AtT20 in mouse pituitary cells. The proliferative capacity and related molecular mechanisms of pituitary tumor cells were then analyzed. METHODS: Mouse AtT20 pituitary adenoma cells were divided into a control group (Pa group), a STAT3 inhibitor vehicle group (PA + DMSO group), a STAT3 inhibitor group (PA + BP-1-102 group), a Fascin-1 negative control group (PA + neg-siRNA group) and a Fascin-1 silenced group (PA + Fascin-siRNA group). The related protein expression and cell proliferation of the five groups were measured using immunofluorescence, Western blot and real-time RT-PCR, whereas their apoptosis and cell cycle were evaluated using CCK-8 and flow cytometry. RESULTS: Proliferation of AtT20 cells is inhibited with BP-1-102 enhanced apoptosis, at the same time reduced the expression of Fascin-1 and N-cadherin, and increased the expression of E-cadherin. After inhibiting Fascin-1, the expression of STAT3 decreased, the expression of N-cadherin decreased and the expression of E-cadherin increased. CONCLUSIONS: BP-1-102 is a novel drug with a great potential in pituitary tumors. Given their important roles in the growth of pituitary adenomas, STAT3 and Fascin-1 can be used as new treatment targets.
Asunto(s)
Adenoma/metabolismo , Proliferación Celular , Proteínas de Microfilamentos/metabolismo , Neoplasias Hipofisarias/metabolismo , Receptores Odorantes/metabolismo , Factor de Transcripción STAT3/metabolismo , Ácidos Aminosalicílicos/administración & dosificación , Animales , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Ratones , Interferencia de ARN , Transducción de Señal/efectos de los fármacos , Sulfonamidas/administración & dosificaciónRESUMEN
Photosystem I (PSI) is one of the two photosystems in photosynthesis, and performs a series of electron transfer reactions leading to the reduction of ferredoxin. In higher plants, PSI is surrounded by four light-harvesting complex I (LHCI) subunits, which harvest and transfer energy efficiently to the PSI core. The crystal structure of PSI-LHCI supercomplex has been analyzed up to 2.6 Å resolution, providing much information on the arrangement of proteins and cofactors in this complicated supercomplex. Here we have optimized crystallization conditions, and analyzed the crystal structure of PSI-LHCI at 2.4 Å resolution. Our structure showed some shift of the LHCI, especially the Lhca4 subunit, away from the PSI core, suggesting the indirect connection and inefficiency of energy transfer from this Lhca subunit to the PSI core. We identified five new lipids in the structure, most of them are located in the gap region between the Lhca subunits and the PSI core. These lipid molecules may play important roles in binding of the Lhca subunits to the core, as well as in the assembly of the supercomplex. The present results thus provide novel information for the elucidation of the mechanisms for the light-energy harvesting, transfer and assembly of this supercomplex.
Asunto(s)
Clorofila/metabolismo , Complejo de Proteína del Fotosistema I/metabolismo , Fotosíntesis/fisiologíaRESUMEN
The family Filoviridae contains many important human viruses, including Marburg virus (MARV) and Ebola virus (EBOV). Menglà virus (MLAV), a newly discovered filovirus, is considered a potential human pathogen. The VP30 C-terminal domain (CTD) of these filoviruses plays an essential role in virion assembly. In common with other filoviruses, MLAV VP30 CTD mainly exists as a dimer in solution. In this work, we determined the crystal structure of recombinant MLAV VP30 CTD monomer, verifying that C-terminal helix-7 (H7) is critical for the dimerization process. This study provides a preliminary model for investigation of MLAV VP30 CTD as an anti-filovirus drug development target.
Asunto(s)
Infecciones por Filoviridae/virología , Filoviridae/química , Proteínas Virales/química , Animales , Cristalografía por Rayos X , Descubrimiento de Drogas , Modelos Moleculares , Conformación Proteica en Hélice alfa , Dominios Proteicos , Multimerización de ProteínaRESUMEN
Hepatocellular carcinoma (HCC) is one of the most common tumors worldwide with high prevalence and lethality. The oncogenic phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) pathway is a classic dysregulated pathway involved in the pathogenesis of HCC. However, the underlying mechanism for how PI3K/AKT/mTOR pathway aberrantly activates HCC has not been entirely elucidated. The recognition of the functional roles of long non-coding RNAs (lncRNAs) in PI3K/AKT/mTOR signaling axis sheds light on a new dimension to our understanding of hepatocarcinogenesis. In this review, we comprehensively summarize 67 dysregulated PI3K/AKT/mTOR pathway-related lncRNAs in HCC. Many studies have indicated that the 67 dysregulated lncRNAs show oncogenic or anti-oncogenic effects in HCC by regulation on epigenetic, transcriptional and post-transcriptional levels and they play pivotal roles in the initiation of HCC in diverse biological processes like proliferation, metastasis, drug resistance, radio-resistance, energy metabolism, autophagy and so on. Besides, many of these lncRNAs are associated with clinicopathological features and clinical prognosis in HCC, which may provide a potential future application in the diagnosis and therapy of HCC.
Asunto(s)
Carcinoma Hepatocelular/genética , Neoplasias Hepáticas/genética , Proteína Oncogénica v-akt/genética , Fosfatidilinositol 3-Quinasas/genética , ARN Largo no Codificante/genética , Transducción de Señal/genética , Serina-Treonina Quinasas TOR/genética , Animales , Carcinoma Hepatocelular/tratamiento farmacológico , Humanos , Neoplasias Hepáticas/tratamiento farmacológico , Proteína Oncogénica v-akt/efectos de los fármacos , Fosfatidilinositol 3-Quinasas/efectos de los fármacos , ARN Largo no Codificante/efectos de los fármacos , Transducción de Señal/efectos de los fármacos , Serina-Treonina Quinasas TOR/efectos de los fármacosRESUMEN
Light is a key limiting factor of plant growth and development under the canopy. Specific light signals, such as a low ratio of red : far-red (R:FR) light, trigger the shade avoidance response, which affects hypocotyl, stem, and leaf growth. Although multiple components mediating shade avoidance responses have been identified in the past few decades, the underlying regulatory mechanism remains unclear. In this study, we found that the far-red elongated hypocotyls 3 (fhy3) mutant exhibited longer hypocotyls and increased expression levels of core shade avoidance response genes under low R:FR shade conditions compared with the wild type No-0, suggesting that FHY3 negatively regulates shade avoidance responses. Yeast one-hybrid, chromatin immunoprecipitation, and RT-qPCR assays revealed that FHY3 directly binds to the promoters and gene body of PHYTOCHROME RAPIDLY REGULATED1 (PAR1) and PAR2 and activates their expression to inhibit shade responses. Furthermore, the overexpression of PAR1 or PAR2 rescued the enhanced shade avoidance responses of fhy3, indicating that both genes are direct downstream targets of FHY3 that mediate shade avoidance responses. Our findings demonstrate that the light-signalling protein FHY3 positively regulates the transcription of PAR1 and PAR2, which encode two key negative regulators of shade avoidance responses, thus repressing plant responses to shade signals.
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Proteínas de Arabidopsis/metabolismo , Arabidopsis/fisiología , Oscuridad , Fitocromo/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Regulación de la Expresión Génica de las Plantas , Hipocótilo/crecimiento & desarrollo , Fitocromo/genética , Plantas Modificadas Genéticamente , Regiones Promotoras Genéticas , Unión Proteica , Transcripción GenéticaRESUMEN
A series of 4-aminoquinazolines derivatives containing hydrophilic group were designed and identified as potent Pan-PI3K inhibitors in this study. The results of antiproliferative assays in vitro showed that this series of compounds had strong inhibition of tumor growth, especially compound 7b for MCF-7 cells but weak inhibition to normal cells. PI3K kinase assay showed that 7b had high activity for three PI3K isoforms with the IC50 values of picomole. The western blot assay indicated that 7b could decrease the phospho-Akt (S473) in a dose-dependent manner. Further experiments showed that 7b could induce apoptosis in MCF-7 cells. Four key hydrogen bonding interactions were found in the docking of 7b with PI3K kinase. All these results suggested that 7b is a potent PI3K inhibitor and could be considered as a potential candidate for the development of anticancer agents.
Asunto(s)
Fosfatidilinositol 3-Quinasas/metabolismo , Inhibidores de Proteínas Quinasas/uso terapéutico , Quinazolinas/química , Quinazolinas/síntesis química , Humanos , Estructura Molecular , Inhibidores de Proteínas Quinasas/farmacologíaRESUMEN
Phosphatidylinositol 3-kinase (PI3K) pathway regulates various cellular processes, such as proliferation, growth, autophagy and apoptosis. Class I PI3K is frequently mutated and overexpressed in a lot of human cancers and PI3K was considered as a target for therapeutic treatment of cancer. In this study, we designed and synthesized a series of 1,6-disubstituted-1H-benzo[d]imidazoles derivatives and evaluated their anticancer activity and the compound 8i was identified as a lead compound. Compound 8i with the most potent antiproliferative activity was selected for further biological mechanism. The PI3K kinase assay have shown potent efficiency against four subtypes of PI3K with an IC50 of 0.5-1.9â¯nM. Molecular docking showed a possible formation of H-bonding with essential amino acid residues. Meanwhile, western blot assay indicated that 8i inhibited cell proliferation via suppression of PI3K kinase activity and subsequently blocked PI3K/Akt pathway activation in HCT116 cells. In addition, 8i could inhibit the migration and invasion ability of HCT116 cells and could induce apoptosis of HCT116 cells.
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Antineoplásicos/síntesis química , Antineoplásicos/farmacología , Imidazoles/síntesis química , Imidazoles/farmacología , Fosfatidilinositol 3-Quinasas/metabolismo , Inhibidores de las Quinasa Fosfoinosítidos-3/síntesis química , Inhibidores de las Quinasa Fosfoinosítidos-3/farmacología , Antineoplásicos/química , Sitios de Unión , Carcinoma , Supervivencia Celular/efectos de los fármacos , Neoplasias del Colon , Diseño de Fármacos , Células HCT116 , Humanos , Imidazoles/química , Modelos Moleculares , Fosfatidilinositol 3-Quinasas/química , Inhibidores de las Quinasa Fosfoinosítidos-3/química , Conformación ProteicaRESUMEN
MAIN CONCLUSION: The macroalga Bryopsis corticulans relies on a sustained protective NPQ and a peculiar body architecture to efficiently adapt to the extreme light changes of intertidal shores. During low tides, intertidal algae experience prolonged high light stress. Efficient dissipation of excess light energy, measured as non-photochemical quenching (NPQ) of chlorophyll fluorescence, is therefore required to avoid photodamage. Light-harvesting regulation was studied in the intertidal macroalga Bryopsis corticulans, during high light and air exposure. Photosynthetic capacity and NPQ kinetics were assessed in different filament layers of the algal tufts and in intact chloroplasts to unravel the nature of NPQ in this siphonous green alga. We found that the morphology and pigment composition of the B. corticulans body provides functional segregation between surface sunlit filaments (protective state) and those that are underneath and undergo severe light attenuation (light-harvesting state). In the surface filaments, very high and sustained NPQ gradually formed. NPQ induction was triggered by the formation of transthylakoid proton gradient and independent of the xanthophyll cycle. PsbS and LHCSR proteins seem not to be active in the NPQ mechanism activated by this alga. Our results show that B. corticulans endures excess light energy pressure through a sustained protective NPQ, not related to photodamage, as revealed by the unusually quick restoration of photosystem II (PSII) function in the dark. This might suggest either the occurrence of transient PSII photoinactivation or a fast rate of PSII repair cycle.
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Chlorophyta/anatomía & histología , Chlorophyta/fisiología , Oxígeno/metabolismo , Complejo de Proteína del Fotosistema II/metabolismo , Clorofila/metabolismo , Chlorophyta/citología , Cloroplastos/fisiología , Cloroplastos/efectos de la radiación , Cinética , Luz , Complejos de Proteína Captadores de Luz/metabolismo , Complejos de Proteína Captadores de Luz/efectos de la radiación , Fotosíntesis/efectos de la radiación , Complejo de Proteína del Fotosistema II/efectos de la radiación , Algas Marinas , Estrés Fisiológico , Olas de MareaRESUMEN
The abnormal activation of PI3K signaling pathway leads to the occurrence of various cancers. The PI3Kα is frequently mutated and overexpressed in many human cancers. Therefore, the PI3Kα was considered as a promising target in therapeutic treatment of cancer. In this study, two series of compounds containing 2H-benzo[b][1,4]oxazin-3(4H)-one and 2H-benzo[b][1,4]oxazine scaffold were synthesized and evaluated antiproliferative activities against three cancer cell lines, including HCT-116, MDA-MB-231 and SNU638. Compound 7f with the most potent antiproliferative activity was selected for further evaluation on normal cells and PI3K kinase. Studies indicated that compound 7f could decrease the phospho-Akt (T308) in a dose-dependent manner. Four key hydrogen bonding interactions were found in the docking of 7f with PI3K enzyme. All the results suggested that 7f was a potent PI3Kα inhibitor.
Asunto(s)
Antineoplásicos/farmacología , Fosfatidilinositol 3-Quinasa Clase I/antagonistas & inhibidores , Diseño de Fármacos , Oxazinas/farmacología , Inhibidores de Proteínas Quinasas/farmacología , Antineoplásicos/síntesis química , Antineoplásicos/química , Proliferación Celular/efectos de los fármacos , Fosfatidilinositol 3-Quinasa Clase I/metabolismo , Relación Dosis-Respuesta a Droga , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Simulación del Acoplamiento Molecular , Estructura Molecular , Oxazinas/síntesis química , Oxazinas/química , Inhibidores de Proteínas Quinasas/síntesis química , Inhibidores de Proteínas Quinasas/química , Relación Estructura-Actividad , Células Tumorales CultivadasRESUMEN
Photosystem I (PSI)-light-harvesting complex I (LHCI) super-complex and its sub-complexes PSI core and LHCI, were purified from a unicellular red alga Cyanidioschyzon merolae and characterized. PSI-LHCI of C. merolae existed as a monomer with a molecular mass of 580 kDa. Mass spectrometry analysis identified 11 subunits (PsaA, B, C, D, E, F, I, J, K, L, O) in the core complex and three LHCI subunits, CMQ142C, CMN234C, and CMN235C in LHCI, indicating that at least three Lhcr subunits associate with the red algal PSI core. PsaG was not found in the red algae PSI-LHCI, and we suggest that the position corresponding to Lhca1 in higher plant PSI-LHCI is empty in the red algal PSI-LHCI. The PSI-LHCI complex was separated into two bands on native PAGE, suggesting that two different complexes may be present with slightly different protein compositions probably with respective to the numbers of Lhcr subunits. Based on the results obtained, a structural model was proposed for the red algal PSI-LHCI. Furthermore, pigment analysis revealed that the C. merolae PSI-LHCI contained a large amount of zeaxanthin, which is mainly associated with the LHCI complex whereas little zeaxanthin was found in the PSI core. This indicates a unique feature of the carotenoid composition of the Lhcr proteins and may suggest an important role of Zea in the light-harvesting and photoprotection of the red algal PSI-LHCI complex.
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Complejos de Proteína Captadores de Luz/aislamiento & purificación , Complejo de Proteína del Fotosistema I/aislamiento & purificación , Rhodophyta/metabolismo , Secuencia de Aminoácidos , Complejos de Proteína Captadores de Luz/química , Complejos de Proteína Captadores de Luz/metabolismo , Modelos Biológicos , Oxígeno/metabolismo , Péptidos/metabolismo , Complejo de Proteína del Fotosistema I/química , Complejo de Proteína del Fotosistema I/metabolismo , Pigmentos Biológicos/metabolismo , Multimerización de Proteína , Subunidades de Proteína/química , Subunidades de Proteína/metabolismo , Alineación de Secuencia , Espectrometría de FluorescenciaRESUMEN
A novel super-complex of photosystem I (PSI)-light-harvesting complex I (LHCI) was isolated from a siphonaceous marine green alga, Bryopsis corticulans. The super-complex contained 9-10 Lhca antennas as external LHCI bound to the core complex. The super-complex was further disintegrated into PSI core and LHCI sub-complexes, and analysis of the pigment compositions by high-performance liquid chromatography revealed unique characteristics of the B. corticulans PSI in that one PSI core contained around 14 α-carotenes and 1-2 ε-carotenes. This is in sharp contrast to the PSI core from higher plants and most cyanobacteria where only ß-carotenes were present, and is the first report for an α-carotene-type PSI core complex among photosynthetic eukaryotes, suggesting a structural flexibility of the PSI core. Lhca antennas from B. corticulans contained seven kinds of carotenoids (siphonaxanthin, all-trans neoxanthin, 9'-cis neoxanthin, violaxanthin, siphonein, ε-carotene, and α-carotene) and showed a high carotenoid:chlorophyll ratio of around 7.5:13. PSI-LHCI super-complex and PSI core showed fluorescence emission peaks at 716 and 718 nm at 77 K, respectively; whereas two Lhca oligomers had fluorescence peaks at 681 and 684 nm, respectively. By comparison with spinach PSI preparations, it was found that B. corticulans PSI had less red chlorophylls, most of them are present in the core complex but not in the outer light-harvesting systems. These characteristics may contribute to the fine tuning of the energy transfer network, and to acclimate to the ever-changing light conditions under which the unique green alga inhabits.
Asunto(s)
Chlorophyta/metabolismo , Complejos de Proteína Captadores de Luz/metabolismo , Complejo de Proteína del Fotosistema I/metabolismo , Carotenoides/química , Carotenoides/metabolismo , Clorofila/fisiología , Cromatografía Líquida de Alta Presión , Regulación de la Expresión Génica de las Plantas/fisiología , Complejos de Proteína Captadores de Luz/química , Complejos de Proteína Captadores de Luz/genética , Complejo de Proteína del Fotosistema I/química , Complejo de Proteína del Fotosistema I/genéticaRESUMEN
Nowadays, ultra-wide cross section highway is a hotspot in construction and brings some unique noise distribution characteristics. In this work, we further investigate noise distribution characteristics of diverse building layouts along ultra-wide cross section highway in Guangdong Province with multiple noise mitigation measures. By the aid of vehicle noise emission model and noise mapping, the influence of high-rise building layouts and shielding in the urban planning on noise mitigation is also considered. Some key findings are summarized as follows: (1) Under the same distance, the noise level of non-frontage building facades is higher than frontage building facades. After taking noise reduction measures, the noise reduction effect of non-street-facing building facades, buildings facing the road, and buildings at a long distance to the road is greater than street-facing building facades, buildings sideways to the road, and buildings at a short distance; (2) the distribution trend of insertion loss (IL) of non-frontage buildings is influenced by the height of the frontage buildings. Specifically, the trend of insertion loss first increases and then decreases as the floor rises when the height of non-frontage buildings is higher than frontage buildings. Comparatively, the trend of insertion loss decreases as the floor rises when the height of non-frontage buildings is equal to frontage buildings; (3) when double noise reduction measures are implemented, the noise distribution trend in buildings is similar to that observed with individual noise reduction measure, where the difference between both is only 0.6 dB(A). Thanks to the high representativeness of the case area, this work can provide some design guidance for the urban planning and the selection of noise reduction measures along the ultra-wide cross section highway.
Asunto(s)
Ruido del Transporte , Emisiones de VehículosRESUMEN
Chloroplast development underpins plant growth, by facilitating not only photosynthesis but also other essential biochemical processes. Nonetheless, the regulatory mechanisms and functional components of chloroplast development remain largely uncharacterized due to their complexity. In our study, we identified a plastid-targeted gene, ATYCO/RP8/CDB1, as a critical factor in early chloroplast development in Arabidopsis thaliana. YCO knock-out mutant (yco) exhibited a seedling-lethal, albino phenotype, resulting from dysfunctional chloroplasts lacking thylakoid membranes. Conversely, YCO knock-down mutants produced a chlorophyll-deficient cotyledon and normal leaves when supplemented with sucrose. Transcription analysis also revealed that YCO deficiency could be partially compensated by sucrose supplementation, and that YCO played different roles in the cotyledons and the true leaves. In YCO knock-down mutants, the transcript levels of plastid-encoded RNA polymerase (PEP)-dependent genes and nuclear-encoded photosynthetic genes, as well as the accumulation of photosynthetic proteins, were significantly reduced in the cotyledons. Moreover, the chlorophyll-deficient phenotype in YCO knock-down line can be effectively suppressed by inhibition of PSI cyclic electron transport activity, implying an interaction between YCO and PSI cyclic electron transport. Taken together, our findings de underscore the vital role of YCO in early chloroplast development and photosynthesis.