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1.
J Physiol ; 602(4): 713-736, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38294945

RESUMEN

In the resting state, cortical neurons can fire action potentials spontaneously but synchronously (Up state), followed by a quiescent period (Down state) before the cycle repeats. Extracellular recordings in the infragranular layer of cortex with a micro-electrode display a negative deflection (depth-negative) during Up states and a positive deflection (depth-positive) during Down states. The resulting slow wave oscillation (SWO) has been studied extensively during sleep and under anaesthesia. However, recent research on the balanced nature of synaptic excitation and inhibition has highlighted our limited understanding of its genesis. Specifically, are excitation and inhibition balanced during SWOs? We analyse spontaneous local field potentials (LFPs) during SWOs recorded from anaesthetised rats via a multi-channel laminar micro-electrode and show that the Down state consists of two distinct synaptic states: a Dynamic Down state associated with depth-positive LFPs and a prominent dipole in the extracellular field, and a Static Down state with negligible ( ≈ 0 mV $ \approx 0{\mathrm{\;mV}}$ ) LFPs and a lack of dipoles extracellularly. We demonstrate that depth-negative and -positive LFPs are generated by a shift in the balance of synaptic excitation and inhibition from excitation dominance (depth-negative) to inhibition dominance (depth-positive) in the infragranular layer neurons. Thus, although excitation and inhibition co-tune overall, differences in their timing lead to an alternation of dominance, manifesting as SWOs. We further show that Up state initiation is significantly faster if the preceding Down state is dynamic rather than static. Our findings provide a coherent picture of the dependence of SWOs on synaptic activity. KEY POINTS: Cortical neurons can exhibit repeated cycles of spontaneous activity interleaved with periods of relative silence, a phenomenon known as 'slow wave oscillation' (SWO). During SWOs, recordings of local field potentials (LFPs) in the neocortex show depth-negative deflection during the active period (Up state) and depth-positive deflection during the silent period (Down state). Here we further classified the Down state into a dynamic phase and a static phase based on a novel method of classification and revealed non-random, stereotypical sequences of the three states occurring with significantly different transitional kinetics. Our results suggest that the positive and negative deflections in the LFP reflect the shift of the instantaneous balance between excitatory and inhibitory synaptic activity of the local cortical neurons. The differences in transitional kinetics may imply distinct synaptic mechanisms for Up state initiation. The study may provide a new approach for investigating spontaneous brain rhythms.


Asunto(s)
Anestesia , Neocórtex , Ratas , Animales , Neocórtex/fisiología , Potenciales de Acción/fisiología , Neuronas/fisiología , Sueño/fisiología
2.
Nucleic Acids Res ; 50(4): 2319-2333, 2022 02 28.
Artículo en Inglés | MEDLINE | ID: mdl-35141752

RESUMEN

Staphylococcus aureus is a notorious and globally distributed pathogenic bacterium. New strategies to develop novel antibiotics based on intrinsic bacterial toxin-antitoxin (TA) systems have been recently reported. Because TA systems are present only in bacteria and not in humans, these distinctive systems are attractive targets for developing antibiotics with new modes of action. S. aureus PemIK is a type II TA system, comprising the toxin protein PemK and the labile antitoxin protein PemI. Here, we determined the crystal structures of both PemK and the PemIK complex, in which PemK is neutralized by PemI. Our biochemical approaches, including fluorescence quenching and polarization assays, identified Glu20, Arg25, Thr48, Thr49, and Arg84 of PemK as being important for RNase function. Our study indicates that the active site and RNA-binding residues of PemK are covered by PemI, leading to unique conformational changes in PemK accompanied by repositioning of the loop between ß1 and ß2. These changes can interfere with RNA binding by PemK. Overall, PemK adopts particular open and closed forms for precise neutralization by PemI. This structural and functional information on PemIK will contribute to the discovery and development of novel antibiotics in the form of peptides or small molecules inhibiting direct binding between PemI and PemK.


Asunto(s)
Antitoxinas , Staphylococcus aureus , Antibacterianos/metabolismo , Antitoxinas/genética , Antitoxinas/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , ARN/metabolismo , Staphylococcus aureus/genética , Staphylococcus aureus/metabolismo
3.
Int J Mol Sci ; 25(2)2024 Jan 12.
Artículo en Inglés | MEDLINE | ID: mdl-38256057

RESUMEN

Mycobacterium tuberculosis, a major cause of mortality from a single infectious agent, possesses a remarkable mycobacterial cell envelope. Penicillin-Binding Proteins (PBPs) are a family of bacterial enzymes involved in the biosynthesis of peptidoglycan. PBP4 (DacB) from M. tuberculosis (MtbPBP4) has been known to function as a carboxypeptidase, and the role and significance of carboxypeptidases as targets for anti-tuberculosis drugs or antibiotics have been extensively investigated over the past decade. However, their precise involvement remains incompletely understood. In this study, we employed predictive modeling and analyzed the three-dimensional structure of MtbPBP4. Interestingly, MtbPBP4 displayed a distinct domain structure compared to its homologs. Docking studies with meropenem verified the presence of active site residues conserved in PBPs. These findings establish a structural foundation for comprehending the molecular function of MtbPBP4 and offer a platform for the exploration of novel antibiotics.


Asunto(s)
Mycobacterium tuberculosis , Proteínas de Unión a las Penicilinas/genética , Antituberculosos , Membrana Celular , Pared Celular
4.
Semin Cancer Biol ; 69: 178-189, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-31419527

RESUMEN

Cancer is an outrageous disease with uncontrolled differentiation, growth, and migration to the other parts of the body. It is the second-most common cause of death both in the U.S. and worldwide. Current conventional therapies, though much improved and with better prognosis, have several limitations. Chemotherapeutic agents, for instance, are cytotoxic to both tumor and healthy cells, and the non-specific distribution of drugs at tumor sites limits the dose administered. Nanotechnology, which evolved from the coalescence and union of varied scientific disciplines, is a novel science that has been the focus of much research. This technology is generating more effective cancer therapies to overcome biomedical and biophysical barriers against standard interventions in the body; its unique magnetic, electrical, and structural properties make it a promising tool. This article reviews endogenous- and exogenous-based stimulus-responsive drug delivery systems designed to overcome the limitations of conventional therapies. The article also summarizes the study of nanomaterials, including polymeric, gold, silver, magnetic, and quantum dot nanoparticles. Though an array of drug delivery systems has so far been proposed, there remain many challenges and concerns that should be addressed in order to fill the gaps in the field. Prominence is given to drug delivery systems that employ external- and internal-based stimuli and that are emerging as promising tools for cancer therapeutics in clinical settings.


Asunto(s)
Antineoplásicos/administración & dosificación , Sistemas de Liberación de Medicamentos , Nanomedicina , Nanopartículas/administración & dosificación , Nanoestructuras/química , Neoplasias/tratamiento farmacológico , Animales , Humanos , Nanopartículas/química , Neoplasias/patología
5.
Semin Cancer Biol ; 69: 293-306, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-31260733

RESUMEN

Colorectal cancer (CRC) is one of the deadliest diseases worldwide due to a lack of early detection methods and appropriate drug delivery strategies. Conventional imaging techniques cannot accurately distinguish benign from malignant tissue, leading to frequent misdiagnosis or diagnosis at late stages of the disease. Novel screening tools with improved accuracy and diagnostic precision are thus required to reduce the mortality burden of this malignancy. Additionally, current therapeutic strategies, including radio- and chemotherapies carry adverse side effects and are limited by the development of drug resistance. Recent advances in nanotechnology have rendered it an attractive approach for designing novel clinical solutions for CRC. Nanoparticle-based formulations could assist early tumor detection and help to overcome the limitations of conventional therapies including poor aqueous solubility, nonspecific biodistribution and limited bioavailability. In this review, we shed light on various types of nanoparticles used for diagnosis and drug delivery in CRC. In addition, we will explore how these nanoparticles can improve diagnostic accuracy and promote selective drug targeting to tumor sites with increased efficiency and reduced cytotoxicity against healthy colon tissue.


Asunto(s)
Antineoplásicos/administración & dosificación , Neoplasias Colorrectales/diagnóstico , Neoplasias Colorrectales/tratamiento farmacológico , Sistemas de Liberación de Medicamentos , Imagen Multimodal/métodos , Nanopartículas/administración & dosificación , Nanotecnología/métodos , Animales , Neoplasias Colorrectales/diagnóstico por imagen , Humanos , Nanopartículas/química
6.
Sensors (Basel) ; 22(20)2022 Oct 12.
Artículo en Inglés | MEDLINE | ID: mdl-36298086

RESUMEN

In this work, we fabricate cesium lead bromide nanofibers (CsPbBr3 NFs) via the attachment of cesium lead bromide nanocrystals (CsPbBr3 NCs) on the surface of electrospun cellulose nanofibers (CNFs) and employ them in a sensor to effectively detect gaseous nitrogen. The CsPbBr3 NFs are produced initially by producing CsPbBr3 NCs through hot injection and dispersing on hexane, followed by dipping CNFs and ultrasonicate for 1 h. Morphological characterization through visual, SEM and TEM image, and crystalline structure analysis by XRD and FT-IR analysis of CsPbBr3 NFs and NCs show similar spectra except for PL due to unavoidable damage during the ultrasonication. Gaseous nitrogen is subsequently detected using the photoluminescence (PL) property of CsPbBr3 NFs, in which the PL intensity dramatically decreases under various flow rate. Therefore, we believe that the proposed CsPbBr3 NFs show significant promise for use in detection sensors in various industrial field and decrease the potential of fatal damage to workers due to suffocation.


Asunto(s)
Celulosa , Nanocompuestos , Humanos , Celulosa/química , Hexanos , Espectroscopía Infrarroja por Transformada de Fourier , Cesio , Nitrógeno
7.
Alzheimers Dement ; 18(8): 1484-1497, 2022 08.
Artículo en Inglés | MEDLINE | ID: mdl-34845818

RESUMEN

INTRODUCTION: Pre-analytical sample handling might affect the results of Alzheimer's disease blood-based biomarkers. We empirically tested variations of common blood collection and handling procedures. METHODS: We created sample sets that address the effect of blood collection tube type, and of ethylene diamine tetraacetic acid plasma delayed centrifugation, centrifugation temperature, aliquot volume, delayed storage, and freeze-thawing. We measured amyloid beta (Aß)42 and 40 peptides with six assays, and Aß oligomerization-tendency (OAß), amyloid precursor protein (APP)699-711 , glial fibrillary acidic protein (GFAP), neurofilament light (NfL), total tau (t-tau), and phosphorylated tau181. RESULTS: Collection tube type resulted in different values of all assessed markers. Delayed plasma centrifugation and storage affected Aß and t-tau; t-tau was additionally affected by centrifugation temperature. The other markers were resistant to handling variations. DISCUSSION: We constructed a standardized operating procedure for plasma handling, to facilitate introduction of blood-based biomarkers into the research and clinical settings.


Asunto(s)
Enfermedad de Alzheimer , Antígenos de Grupos Sanguíneos , Péptidos beta-Amiloides , Biomarcadores , Humanos , Estándares de Referencia , Manejo de Especímenes , Proteínas tau
8.
Mikrochim Acta ; 188(11): 365, 2021 10 06.
Artículo en Inglés | MEDLINE | ID: mdl-34613481

RESUMEN

An ultrasensitive electrochemical immunosensor has been prepared using an immunofunctionalized zirconium (Zr)-based metal-organic framework (MOF) with gold (Au) decoration Au@UiO-66(NH2) composite-coated glassy carbon electrode (GCE) for the determination of infectious hepatitis B surface antigen (HBsAg). We fabricated GCE with specific composite via immune-functionalization using anti-HBsAg with Au nanoparticles embedded in UiO-66(NH2). The electrochemical sensing performance of the immunofunctionalized Au@UiO-66(NH2)/GCE with HBsAg was characterized by cyclic voltammetry and differential pulse voltammetry. Under optimized conditions, there was a linear dynamic relationship in the buffer system between the electrical signal and HBsAg levels over the range 1.13 fg mL-1-100 ng mL-1 (R2 = 0.999) with a detection limit of 1.13 fg mL-1. The total analysis time was 15 min per sample. Further validations were performed with HBsAg-spiked human serum samples, and similar detection limits as in the buffer system were observed with reduced signal intensities at lower concentrations of HBsAg (1, 10, and 100 fg mL-1) and minimal interference. The HBsAg electrochemical immunosensing assay had good selectivity and excellent reproducibility, thereby indicating its significant potential in the super-fast diagnosis of hepatitis B.


Asunto(s)
Estructuras Metalorgánicas
9.
Nucleic Acids Res ; 46(12): 6371-6386, 2018 07 06.
Artículo en Inglés | MEDLINE | ID: mdl-29878152

RESUMEN

Streptococcus pneumonia has attracted increasing attention due to its resistance to existing antibiotics. TA systems are essential for bacterial persistence under stressful conditions such as nutrient deprivation, antibiotic treatment, and immune system attacks. In particular, S. pneumoniae expresses the HicBA TA gene, which encodes the stable HicA toxin and the labile HicB antitoxin. These proteins interact to form a non-toxic TA complex under normal conditions, but the toxin is activated by release from the antitoxin in response to unfavorable growth conditions. Here, we present the first crystal structure showing the complete conformation of the HicBA complex from S. pneumonia. The structure reveals that the HicA toxin contains a double-stranded RNA-binding domain that is essential for RNA recognition and that the C-terminus of the HicB antitoxin folds into a ribbon-helix-helix DNA-binding motif. The active site of HicA is sterically blocked by the N-terminal region of HicB. RNase activity assays show that His36 is essential for the ribonuclease activity of HicA, and nuclear magnetic resonance (NMR) spectra show that several residues of HicB participate in binding to the promoter DNA of the HicBA operon. A toxin-mimicking peptide that inhibits TA complex formation and thereby increases toxin activity was designed, providing a novel approach to the development of new antibiotics.


Asunto(s)
Proteínas Bacterianas/química , Toxinas Bacterianas/química , Streptococcus pneumoniae , Sistemas Toxina-Antitoxina , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/toxicidad , Toxinas Bacterianas/metabolismo , Toxinas Bacterianas/toxicidad , Dominio Catalítico , Modelos Moleculares , Regiones Promotoras Genéticas , Dominios Proteicos , Ribonucleasas/química , Ribonucleasas/metabolismo
10.
J Nutr ; 149(5): 730-737, 2019 05 01.
Artículo en Inglés | MEDLINE | ID: mdl-31006816

RESUMEN

BACKGROUND: Although vitamin B-12 (B-12) is known to contribute to the structural and functional development of the brain, it is unclear if B-12 supplementation has any beneficial effect in healthy populations in terms of enhanced neurologic status of the brain or improved cognitive function. OBJECTIVES: We investigated the effect of dietary supplementation of B-12 on the cortical neural activity of well-nourished young adult rats and tested the hypothesis that B-12 supplementation in healthy rats may reduce sensory-evoked neural activity due to enhanced inhibition. METHODS: Female Lister Hooded rats weighing 190-265 g (2-4 mo old) were included in the study. The experimental group was fed with B-12 (cyanocobalamin)-enriched water at a concentration of 1 mg/L, and the control (CON) group with tap water for 3 wk. Animals were then anesthetized and cortical neural responses to whisker stimulation were recorded in vivo through the use of a multichannel microelectrode, from which local field potentials (LFPs) were extracted. RESULTS: Somatosensory-evoked LFP was 25% larger in the B-12 group (4.13 ± 0.24 mV) than in the CON group (3.30 ± 0.21 mV) (P = 0.02). Spontaneous neural activity did not differ between groups; frequency spectra at each frequency bin of interest did not pass the cluster-forming threshold at the 5% significance level. CONCLUSIONS: These findings do not provide evidence supporting the hypothesis of decreased neural activity due to B-12 supplementation. As the spontaneous neural activity was unaffected, the increase in somatosensory-evoked LFP may be due to enhanced afferent signal reaching the barrel cortex from the whisker pad, indicating that B-12-supplemented rats may have enhanced sensitivity to sensory stimulation compared with the CON group. We suggest that this enhancement might be the result of lowered sensory threshold, although the underlying mechanism has yet to be elucidated.


Asunto(s)
Encéfalo/efectos de los fármacos , Suplementos Dietéticos , Sensación/efectos de los fármacos , Umbral Sensorial/efectos de los fármacos , Vibrisas , Vitamina B 12/farmacología , Complejo Vitamínico B/farmacología , Animales , Femenino , Ratas
11.
Nucleic Acids Res ; 45(14): 8564-8580, 2017 Aug 21.
Artículo en Inglés | MEDLINE | ID: mdl-28575388

RESUMEN

Toxin-antitoxin (TA) systems are essential for bacterial persistence under stressful conditions. In particular, Mycobacterium tuberculosis express VapBC TA genes that encode the stable VapC toxin and the labile VapB antitoxin. Under normal conditions, these proteins interact to form a non-toxic TA complex, but the toxin is activated by release from the antitoxin in response to unfavorable conditions. Here, we present the crystal structure of the M. tuberculosis VapBC26 complex and show that the VapC26 toxin contains a pilus retraction protein (PilT) N-terminal (PIN) domain that is essential for ribonuclease activity and that, the VapB26 antitoxin folds into a ribbon-helix-helix DNA-binding motif at the N-terminus. The active site of VapC26 is sterically blocked by the flexible C-terminal region of VapB26. The C-terminal region of free VapB26 adopts an unfolded conformation but forms a helix upon binding to VapC26. The results of RNase activity assays show that Mg2+ and Mn2+ are essential for the ribonuclease activity of VapC26. As shown in the nuclear magnetic resonance spectra, several residues of VapB26 participate in the specific binding to the promoter region of the VapBC26 operon. In addition, toxin-mimicking peptides were designed that inhibit TA complex formation and thereby increase toxin activity, providing a novel approach to the development of new antibiotics.


Asunto(s)
Péptidos Catiónicos Antimicrobianos/metabolismo , Proteínas Bacterianas/metabolismo , Toxinas Bacterianas/metabolismo , Proteínas de Unión al ADN/metabolismo , Glicoproteínas de Membrana/metabolismo , Mycobacterium tuberculosis/metabolismo , Secuencia de Aminoácidos , Péptidos Catiónicos Antimicrobianos/química , Péptidos Catiónicos Antimicrobianos/farmacología , Proteínas Bacterianas/química , Proteínas Bacterianas/genética , Toxinas Bacterianas/química , Toxinas Bacterianas/genética , Calorimetría/métodos , Cristalografía por Rayos X , Proteínas de Unión al ADN/química , Proteínas de Unión al ADN/genética , Interacciones Hidrofóbicas e Hidrofílicas , Magnesio/química , Magnesio/metabolismo , Magnesio/farmacología , Manganeso/química , Manganeso/metabolismo , Manganeso/farmacología , Espectrometría de Masas/métodos , Glicoproteínas de Membrana/química , Glicoproteínas de Membrana/genética , Modelos Moleculares , Mutación , Mycobacterium tuberculosis/genética , Unión Proteica/efectos de los fármacos , Multimerización de Proteína , Estructura Secundaria de Proteína , Estructura Terciaria de Proteína , Ribonucleasas/química , Ribonucleasas/genética , Ribonucleasas/metabolismo , Homología de Secuencia de Aminoácido
12.
Mikrochim Acta ; 186(5): 266, 2019 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-30937623

RESUMEN

The original version of this article unfortunately missed Prof. A.T. Ezhil Vilian's project number in Acknowledgements. The missing project number is 2017R1D1A1B03034977.

13.
Mikrochim Acta ; 186(3): 203, 2019 02 22.
Artículo en Inglés | MEDLINE | ID: mdl-30796594

RESUMEN

The primary objective of this review article is to summarize the development and structural diversity of 2D/3D molybdenum disulfide (MoS2) based modified electrodes for electrochemical sensors and biosensor applications. Hydrothermal, mechanical, and ultrasonic techniques and solution-based exfoliation have been used to synthesize graphene-like 2D MoS2 layers. The unique physicochemical properties of MoS2 and its nanocomposites, including high mechanical strength, high carrier transport, large surface area, excellent electrical conductivity, and rapid electron transport rate, render them useful as efficient transducers in various electrochemical applications. The present review summarizes 2D/3D MoS2-based nanomaterials as an electrochemical platform for the detection and analysis of various biomolecules (e.g., neurotransmitters, NADH, glucose, antibiotics, DNA, proteins, and bacteria) and hazardous chemicals (e.g., heavy metal ions, organic compounds, and pesticides). The substantial improvements that have been achieved in the performance of enzyme-based amperometry, chemiluminescence, and nucleic acid sensors incorporating MoS2-based chemically modified electrodes are also addressed. We also summarize key sensor parameters such as limits of detection (LODs), sensitivity, selectivity, response time, and durability, as well as real applications of the sensing systems in the environmental, pharmaceutical, chemical, industrial, and food analysis fields. Finally, the remaining challenges in designing MoS2 nanostructures suitable for electroanalytical applications are outlined. Graphical abstract • MoS2 based materials exhibit high conductivity and improved electrochemical performance with great potential as a sensing electrode. • The role of MoS2 nanocomposite films and their detection strategies were reviewed. • Biomarkers detection for disease identification and respective clinical treatments were discussed. • Future Challenges, as well as possible research development for "MoS2 nanocomposites", are suggested.

14.
Cell Physiol Biochem ; 50(5): 1869-1881, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30396177

RESUMEN

BACKGROUND/AIMS: The functional relevance of early growth response-1 (EGR1) on cancer invasion remains controversial. The effect of EGR1 on the expression of MMP9, which is important for HNSCC invasion, is still disputed. There is no previous data showing the effect of EGR1 on mouse double minute 2 (MDM2), an enhancer of matrix metalloproteinase 9 (MMP9) expression. Our aim is to clarify the negative correlation between EGR1 expression and head and neck squamous cell carcinoma (HNSCC) metastasis. METHODS: EGR1 mRNA and protein expressions were compared in normal and HNSCC tissues using The Cancer Genome Atlas (TCGA) dataset analysis or immunohistochemistry (IHC), respectively. In vitro cell invasion was evaluated Matrigel invasion assay. EGR1-dependent inhibition of MDM2 transcription was assessed by promoter-luciferase assay and chromatin immunoprecipitation (ChIP). RESULTS: TCGA data showed that EGR1 mRNA levels are significantly higher in normal oral tissues as compared with HNSCC tumor tissues (adjusted P = 1.64x10-16). In addition, nonmetastatic HNSCC tissues showed significantly higher EGR1 mRNA levels as compared with metastatic tissues (adjusted P = 0.023). IHC analysis showed that primary tumor tissues expressed significantly higher levels of nuclear EGR1 compared with paired metastatic lymph node tissues (P < 0.05). EGR1 overexpression downregulated MMP9 and MDM2 protein expression. Consistent with these observations, TCGA data analysis found significantly fewer metastatic patients among a subgroup of population presenting higher EGR1 expressions with lower MMP9 and/or MDM2. CONCLUSION: Our data suggests that EGR1 prevents HNSCC metastasis through downregulation of MMP9 and MDM2. EGR1 might be a potential candidate to attenuate HNSCC metastasis.


Asunto(s)
Carcinoma de Células Escamosas/patología , Regulación hacia Abajo , Proteína 1 de la Respuesta de Crecimiento Precoz/metabolismo , Neoplasias de Cabeza y Cuello/patología , Metaloproteinasa 9 de la Matriz/genética , Proteínas Proto-Oncogénicas c-mdm2/genética , Carcinoma de Células Escamosas/metabolismo , Línea Celular Tumoral , Bases de Datos Genéticas , Proteína 1 de la Respuesta de Crecimiento Precoz/genética , Neoplasias de Cabeza y Cuello/metabolismo , Humanos , Metástasis Linfática/fisiopatología , Metaloproteinasa 9 de la Matriz/metabolismo , Regiones Promotoras Genéticas , Unión Proteica , Proteínas Proto-Oncogénicas c-mdm2/metabolismo , Carcinoma de Células Escamosas de Cabeza y Cuello
15.
Mar Drugs ; 16(6)2018 May 23.
Artículo en Inglés | MEDLINE | ID: mdl-29882898

RESUMEN

Current trends in the application of nanomaterials are emerging in the nano-biotechnological sector for development of medicines. Cyanobacteria (blue-green algae) are photosynthetic prokaryotes that have applications to human health and numerous biological activities as dietary supplements. Cyanobacteria produce biologically active and chemically diverse compounds such as cyclic peptides, lipopeptides, fatty acid amides, alkaloids, and saccharides. More than 50% of marine cyanobacteria are potentially exploitable for the extraction of bioactive substances, which are effective in killing cancer cells by inducing apoptotic death. The current review emphasizes that not even 10% of microalgal bioactive components have reached commercialized platforms due to difficulties related to solubility. Considering these factors, they should be considered as a potential source of natural products for drug discovery and drug delivery approaches. Nanoformulations employing a wide variety of nanoparticles and their polymerized forms could be an emerging approach to the development of new cancer drugs. This review highlights recent research on microalgae-based medicines or compounds as well as their biomedical applications. This review further discusses the facts, limitations, and commercial market trends related to the use of microalgae for industrial and medicinal purposes.


Asunto(s)
Antineoplásicos/uso terapéutico , Factores Biológicos/uso terapéutico , Cianobacterias/metabolismo , Sistemas de Liberación de Medicamentos/métodos , Microalgas/metabolismo , Neoplasias/tratamiento farmacológico , Antineoplásicos/química , Antineoplásicos/aislamiento & purificación , Factores Biológicos/química , Factores Biológicos/aislamiento & purificación , Biotecnología/métodos , Biotecnología/tendencias , Comercio/tendencias , Composición de Medicamentos/métodos , Descubrimiento de Drogas/métodos , Descubrimiento de Drogas/tendencias , Estabilidad de Medicamentos , Humanos , Nanopartículas/química , Nanopartículas/uso terapéutico , Nanotecnología/métodos , Nanotecnología/tendencias , Solubilidad
16.
Biochim Biophys Acta Proteins Proteom ; 1865(1): 65-75, 2017 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-27784646

RESUMEN

Translation initiation, the rate-limiting step in the protein synthesis, is tightly regulated. As one of the translation initiation factors, translation initiation factor 1 (IF1) plays crucial roles not only in translation but also in many cellular processes that are important for genomic stability, such as the activity of RNA chaperones. Here, we characterize the RNA interactions and dynamics of IF1 from Staphylococcus aureus Mu50 (IF1Sa) by NMR spectroscopy. First, the NMR-derived solution structure of IF1Sa revealed that IF1Sa adopts an oligonucleotide/oligosaccharide binding (OB)-fold. Structural comparisons showed large deviations in the α-helix and the following loop, which are potential RNA-binding regions of the OB-fold, as well as differences in the electrostatic potential surface among bacterial IF1s. Second, the 15N NMR relaxation data for IF1Sa indicated the flexible nature of the α-helix and the following loop region of IF1Sa. Third, RNA-binding properties were studied using FP assays and NMR titrations. FP binding assays revealed that IF1Sa binds to RNAs with moderate affinity. In combination with the structural analysis, the NMR titration results revealed the RNA binding sites. Taken together, these results show that IF1Sa binds RNAs with moderate binding affinity via the residues that occupy the large surface area of its ß-barrel. These findings suggest that IF1Sa is likely to bind RNA in various conformations rather than only at a specific site and indicate that the flexible RNA binding mode of IF1Sa is necessary for its interaction with various RNA substrates.


Asunto(s)
Proteínas Bacterianas/química , Factores Procarióticos de Iniciación/química , Proteínas de Unión al ARN/química , Staphylococcus aureus/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/ultraestructura , Sitios de Unión , Espectroscopía de Resonancia Magnética , Resonancia Magnética Nuclear Biomolecular , Iniciación de la Cadena Peptídica Traduccional , Factores Procarióticos de Iniciación/genética , Factores Procarióticos de Iniciación/ultraestructura , Unión Proteica , Estructura Secundaria de Proteína , ARN Bacteriano/química , Proteínas de Unión al ARN/genética , Proteínas de Unión al ARN/ultraestructura , Alineación de Secuencia , Staphylococcus aureus/genética
17.
Anticancer Drugs ; 28(6): 613-622, 2017 07.
Artículo en Inglés | MEDLINE | ID: mdl-28452807

RESUMEN

The effect of oxytocin (OXT) on cancer invasion is controversial. Few studies have examined the effect of early growth response-1 (EGR1) on the invasion of head and neck squamous cell carcinoma (HNSCC). Here, we evaluated how EGR1 affects HNSCC cell migration through the molecular mechanism of OXT in exerting anti-invasion activity. Matrigel invasion and wound-healing assays were used to measure the in-vitro cell migration. The molecular mechanism of OXT was assessed by knockdown or overexpression of EGR1 in HNSCC cells. Three-dimensional (3-D) spheroids formation, followed by the image analysis for quantification was performed. OXT at 500 nmol/l increased mRNA and protein expression of E-cadherin without cytotoxicity. OXT upregulated mRNA and protein expression of EGR1 in 6 h. p53, phosphatase and tensin, and p21 expression was increased in an EGR1-dependent manner with OXT treatment. In addition, OXT significantly downregulated 3-D spheroids' formation according to spheroids' number and size. Our data showed that OXT downregulated HNSCC cell migration by EGR1 upregulation. OXT inhibited spheroids' formation of HNSCC cells under 3-D culture conditions.


Asunto(s)
Carcinoma de Células Escamosas/tratamiento farmacológico , Movimiento Celular/efectos de los fármacos , Proteína 1 de la Respuesta de Crecimiento Precoz/biosíntesis , Neoplasias de Cabeza y Cuello/tratamiento farmacológico , Oxitocina/farmacología , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/patología , Transición Epitelial-Mesenquimal/efectos de los fármacos , Receptores ErbB/metabolismo , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Neoplasias de Cabeza y Cuello/metabolismo , Neoplasias de Cabeza y Cuello/patología , Humanos , Invasividad Neoplásica , Metástasis de la Neoplasia , Esferoides Celulares , Carcinoma de Células Escamosas de Cabeza y Cuello , Células Tumorales Cultivadas , Regulación hacia Arriba/efectos de los fármacos
18.
Molecules ; 22(9)2017 Aug 31.
Artículo en Inglés | MEDLINE | ID: mdl-28858250

RESUMEN

Tuberculosis is an infectious disease caused by Mycobacteriumtuberculosis, which triggers severe pulmonary diseases. Recently, multidrug/extensively drug-resistant tuberculosis strains have emerged and continue to threaten global health. Because of the development of drug-resistant tuberculosis, there is an urgent need for novel antibiotics to treat these drug-resistant bacteria. In light of the clinical importance of M. tuberculosis, 2067 structures of M. tuberculsosis proteins have been determined. Among them, 52 structures have been solved and studied using solution nuclear magnetic resonance (NMR). The functional details based on structural analysis of M. tuberculosis using NMR can provide essential biochemical data for the development of novel antibiotic drugs. In this review, we introduce diverse structural and biochemical studies on M. tuberculosis proteins determined using NMR spectroscopy.


Asunto(s)
Antituberculosos/química , Mycobacterium tuberculosis , Proteínas Bacterianas/antagonistas & inhibidores , Proteínas Bacterianas/química , Descubrimiento de Drogas , Humanos , Terapia Molecular Dirigida , Resonancia Magnética Nuclear Biomolecular , Conformación Proteica , Soluciones , Tuberculosis Pulmonar/tratamiento farmacológico , Tuberculosis Pulmonar/microbiología
19.
Soft Matter ; 12(27): 5847-53, 2016 Jul 06.
Artículo en Inglés | MEDLINE | ID: mdl-27328067

RESUMEN

Directed self-assembly can produce ordered or organized superstructures from pre-existing building blocks through pre-programmed interactions. Encoding desired information into building blocks with specific directionality and strength, however, poses a significant challenge for the development of self-assembled superstructures. Here, we demonstrate that controlling the shape and patchiness of particles trapped at the air-water interface can represent a powerful approach for forming ordered macroscopic complex structures through capillary interactions. We designed hexagram particles using a micromolding method that allowed for precise control over the shape and, more importantly, the chemical patchiness of the particles. The assembly behaviors of these hexagram particles at the air-water interface were strongly affected by chemical patchiness. In particular, two-dimensional millimeter-scale ordered structures could be formed by varying the patchiness of the hexagram particles, and we attribute this effect to the delicate balance between the attractive and repulsive interactions among the patchy hexagram particles. Our results provide important clues for encoding information into patchy particles to achieve macroscopic assemblies via a simple molding technique and potentially pave a new pathway for the programmable assembly of particles at the air-water interface.

20.
Phytother Res ; 30(5): 754-67, 2016 May.
Artículo en Inglés | MEDLINE | ID: mdl-26890810

RESUMEN

Cinnamaldehyde and cinnamaldehyde-derived compounds are candidates for the development of anticancer drugs that have received extensive research attention. In this review, we summarize recent findings detailing the positive and negative aspects of cinnamaldehyde and its derivatives as potential anticancer drug candidates. Furthermore, we describe the in vivo pharmacokinetics and metabolism of cinnamaldehydes. The oxidative and antioxidative properties of cinnamaldehydes, which contribute to their potential in chemotherapy, have also been discussed. Moreover, the mechanism(s) by which cinnamaldehydes induce apoptosis in cancer cells have been explored. In addition, evidence of the regulatory effects of cinnamaldehydes on cancer cell invasion and metastasis has been described. Finally, the application of cinnamaldehydes in treating various types of cancer, including breast, prostate, and colon cancers, has been discussed in detail. The effects of cinnamaldehydes on leukemia, hepatocellular carcinoma, and oral cancer have been summarized briefly. Copyright © 2016 John Wiley & Sons, Ltd.


Asunto(s)
Acroleína/análogos & derivados , Antineoplásicos/farmacología , Neoplasias/tratamiento farmacológico , Acroleína/administración & dosificación , Acroleína/uso terapéutico , Humanos
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