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1.
Arch Biochem Biophys ; 712: 109042, 2021 11 15.
Artículo en Inglés | MEDLINE | ID: mdl-34562470

RESUMEN

RNAs have become a well-known target for chemotherapeutic agents in the recent years. The tails of most eukaryotic m-RNA are characterized by the presence of a long polyadenylate sequence which plays an important role in its growth and maturation. This lays emphasis on development of molecular probes that target the polyadenylate sequence. Cryptolepine (hereafter, CRP) is an indoloquinoline alkaloid well known for its anti-malarial activities. A series of spectroscopic experiments namely absorption studies, fluorimetric studies and circular dichroism studies show that cryptolepine binds with single-stranded polyriboadenylic acid (hereafter, ss-poly (rA)) with a binding constant of ∼5 × 103 M-1 at 25 °C. Moreover thermal denaturation experiments show that the bound form of polyriboadenylic acid shows a characteristic transition profile. Such a profile is indicative of the ability of cryptolepine to induce self-assembly in the polyriboadenylic acid sequence on binding to it. Such ability of CRP to modulate the structural conformation of poly (rA), which in turn may cause functional aspects of the RNA to change, may give us a chance to develop effective alkaloid based chemotherapeutic agents.


Asunto(s)
Alcaloides Indólicos/metabolismo , Poli A/metabolismo , Quinolinas/metabolismo , Polarización de Fluorescencia , Alcaloides Indólicos/química , Conformación de Ácido Nucleico/efectos de los fármacos , Transición de Fase , Poli A/química , Quinolinas/química , Espectrometría de Fluorescencia , Termodinámica , Temperatura de Transición
2.
J Med Ethics ; 40(3): 163-7, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-23454719

RESUMEN

Increased knowledge of the gene-disease associations contributing to common cancer development raises the prospect of population stratification by genotype and other risk factors. Individual risk assessments could be used to target interventions such as screening, treatment and health education. Genotyping neonates, infants or young children as part of a systematic programme would improve coverage and uptake, and facilitate a screening package that maximises potential benefits and minimises harms including overdiagnosis. This paper explores the potential justifications and risks of genotyping children for genetic variants associated with common cancer development within a personalised screening programme. It identifies the ethical and legal principles that might guide population genotyping where the predictive value of the testing is modest and associated risks might arise in the future, and considers the standards required by population screening programme validity measures (such as the Wilson and Jungner criteria including cost-effectiveness and equitable access). These are distinguished from the normative principles underpinning predictive genetic testing of children for adult-onset diseases-namely, to make best-interests judgements and to preserve autonomy. While the case for population-based genotyping of neonates or young children has not yet been made, the justifications for this approach are likely to become increasingly compelling. A modified evaluative and normative framework should be developed, capturing elements from individualistic and population-based approaches. This should emphasise proper communication and genuine parental consent or informed choice, while recognising the challenges associated with making unsolicited approaches to an asymptomatic group. Such a framework would be strengthened by complementary empirical research.


Asunto(s)
Pruebas Genéticas/ética , Pruebas Genéticas/legislación & jurisprudencia , Genotipo , Tamizaje Masivo/ética , Principios Morales , Neoplasias/genética , Adulto , Preescolar , Europa (Continente) , Femenino , Predisposición Genética a la Enfermedad , Humanos , Lactante , Masculino , Consentimiento Paterno , Medicina de Precisión/ética , Valor Predictivo de las Pruebas , Medición de Riesgo , Factores de Riesgo
3.
Indian J Ophthalmol ; 72(6): 902-911, 2024 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-38317323

RESUMEN

PURPOSE: Retinoschisis is a distinctive condition characterized by intraretinal layer clefts, primarily associated with X-linked recessive inheritance due to RS1 gene mutations. This study aims to uncover the RS1 mutation spectrum in a cohort of 22 X-linked retinoschisis cases from South India and emphasizes the genotypic and phenotypic associations within patients harboring only RS1 mutations. METHODS: A total of 22 probands were suspected of having X-linked retinoschisis. All study subjects underwent ophthalmic investigations, including assessments of visual acuity, fundus examination, optical coherence tomography (OCT), and electroretinogram (ERG). RS1 gene screening was conducted using Sanger sequencing, and the pathogenicity of the variants was assessed through Sorting Intolerant from Tolerant (SIFT) and PolyPhen-2 in silico tools. RESULTS: The study found that the probands had an average visual acuity of 0.79 ± 0.39 log of minimum angle of resolution (logMAR), ranging from 0.17 to 1.77. During fundus examination, the probands exhibited a characteristic spoke wheel-like pattern in the macular region. Furthermore, OCT analysis revealed distinct alterations in the inner retinal microstructure, and ERG results consistently showed a reduction in b-wave amplitude. Eventually, Sanger sequencing results showed hemizygous mutations in the RS1 gene in only 12 probands, including a novel missense mutation in the RS1 gene's signal sequence. CONCLUSION: This study provides valuable insights into the spectrum of RS1 mutations in X-linked retinoschisis probands from South India. It reveals distinct genotypic-phenotypic associations and highlights the clinical manifestations associated with the disease pathogenesis.


Asunto(s)
Electrorretinografía , Proteínas del Ojo , Genotipo , Mutación , Fenotipo , Retinosquisis , Tomografía de Coherencia Óptica , Agudeza Visual , Humanos , Retinosquisis/genética , Retinosquisis/diagnóstico , Retinosquisis/fisiopatología , Masculino , India/epidemiología , Tomografía de Coherencia Óptica/métodos , Proteínas del Ojo/genética , Adulto , Agudeza Visual/fisiología , Adolescente , Análisis Mutacional de ADN , Niño , Adulto Joven , Linaje , Femenino , Persona de Mediana Edad , ADN/genética , Retina/patología , Retina/diagnóstico por imagen , Retina/fisiopatología
4.
Genet Med ; 15(6): 423-32, 2013 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-23412607

RESUMEN

Individual risk prediction and stratification based on polygenic profiling may be useful in disease prevention. Risk-stratified population screening based on multiple factors including a polygenic risk profile has the potential to be more efficient than age-stratified screening. In this article, we summarize the implications of personalized screening for breast and prostate cancers. We report the opinions of multidisciplinary international experts who have explored the scientific, ethical, and logistical aspects of stratified screening. We have identified (i) the need to recognize the benefits and harms of personalized screening as compared with existing screening methods, (ii) that the use of genetic data highlights complex ethical issues including discrimination against high-risk individuals by insurers and employers and patient autonomy in relation to genetic testing of minors, (iii) the need for transparency and clear communication about risk scores, about harms and benefits, and about reasons for inclusion and exclusion from the risk-based screening process, and (iv) the need to develop new professional competences and to assess cost-effectiveness and acceptability of stratified screening programs before implementation. We conclude that health professionals and stakeholders need to consider the implications of incorporating genetic information in intervention strategies for health-care planning in the future.


Asunto(s)
Neoplasias de la Mama/diagnóstico , Neoplasias de la Mama/genética , Detección Precoz del Cáncer , Pruebas Genéticas , Genómica , Neoplasias de la Próstata/diagnóstico , Neoplasias de la Próstata/genética , Detección Precoz del Cáncer/ética , Detección Precoz del Cáncer/métodos , Femenino , Privacidad Genética , Pruebas Genéticas/ética , Pruebas Genéticas/legislación & jurisprudencia , Pruebas Genéticas/métodos , Genómica/ética , Genómica/legislación & jurisprudencia , Genómica/métodos , Humanos , Masculino , Opinión Pública , Medición de Riesgo
5.
BMC Fam Pract ; 14: 105, 2013 Jul 24.
Artículo en Inglés | MEDLINE | ID: mdl-23879178

RESUMEN

BACKGROUND: In England, guidance from National Institute for Clinical Excellence (NICE) states women with a family history of breast cancer presenting to primary care should be reassured or referred.We reviewed the evidence for interventions that might be applied in primary care and conducted an audit of whether low risk women are correctly advised and flagged. METHODS: We conducted a literature review to identify modifiable risk factors. We extracted routinely collected data from the computerised medical record systems of 6 general practices (population approximately 30,000); of the variables identified in the guidance. We implemented a quality improvement (QI) intervention called audit-based education (ABE) comparing participant practices with guidelines and each other before and after; we report odds ratios (OR) of any change in data recording. RESULTS: The review revealed evidence for advising on: diet, weight control, physical exercise, and alcohol. The proportion of patients with recordings of family history of: disease, neoplasms, and breast cancer were: 39.3%, 5.1% and 1.3% respectively. There was no significant change in the recording of family history of disease or cancer; OR 1.02 (95% CI 0.98-1.06); and 1.08 (95% CI 0.99-1.17) respectively. Recording of alcohol consumption and smoking both increased significantly; OR 1.36 (95% CI 1.30-1.43); and 1.42 (95% CI 1.27-1.60) respectively. Recording lifestyle advice fell; OR 0.84 (95% CI 0.81-0.88). CONCLUSIONS: The study informs about current data recording and willingness to engage in ABE. Recording of risk factors improved after the intervention. Further QI is needed to achieve adherence to current guidance.


Asunto(s)
Neoplasias de la Mama/prevención & control , Medicina Familiar y Comunitaria/normas , Auditoría Médica/métodos , Anamnesis , Atención Primaria de Salud/normas , Anciano , Neoplasias de la Mama/diagnóstico , Neoplasias de la Mama/genética , Inglaterra , Práctica Clínica Basada en la Evidencia , Medicina Familiar y Comunitaria/educación , Femenino , Indicadores de Salud , Humanos , Masculino , Persona de Mediana Edad , Oportunidad Relativa , Garantía de la Calidad de Atención de Salud/métodos , Derivación y Consulta , Literatura de Revisión como Asunto , Factores de Riesgo
6.
Int J Biol Macromol ; 251: 126189, 2023 Aug 14.
Artículo en Inglés | MEDLINE | ID: mdl-37586624

RESUMEN

Self-structure induction in a single stranded polyriboadenylic acid [poly (rA)] is an auspicious physiological phenomenon which switches off protein production in tumor cells. In the present study, the self-structure induction process in poly (rA) moiety was thoroughly investigated using various steady state and time resolved techniques. Optical melting pattern directly evidenced the formation of self-structured assembly in single stranded poly (rA) upon complexation with quinacrine. Further, UV-absorption spectroscopic studies revealed that quinacrine binds to poly (rA) in co-operative fashion and the indication of intercalative mode of binding first came out with the involvement of around two base pairs of poly (rA) in the complexation. Experimental observations established the unconventional or non-classical intercalation of quinacrine molecule inside self-structured duplex poly (rA) moiety. This complexation was accompanied with negative enthalpy change and positive entropy change; suggesting strong van der Waals and the H-bonding interactions as the major governing forces in the complexation. Moreover, ionic strength dependent binding study established that the non-polyelectrolytic forces were the dominating forces. Further, the photo physical behavior of QN was authenticated using time dependent density functional theory (TDDFT) where both the ground and excited states were exploited.

7.
Health Sci Rep ; 6(4): e1209, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-37077184

RESUMEN

Background and Aims: Since the beginning of the SARS-CoV-2 pandemic, multiple new variants have emerged posing an increased risk to global public health. This study aimed to investigate SARS-CoV-2 variants, their temporal dynamics, infection rate (IFR) and case fatality rate (CFR) in Bangladesh by analyzing the published genomes. Methods: We retrieved 6610 complete whole genome sequences of the SARS-CoV-2 from the GISAID (Global Initiative on Sharing all Influenza Data) platform from March 2020 to October 2022, and performed different in-silico bioinformatics analyses. The clade and Pango lineages were assigned by using Nextclade v2.8.1. SARS-CoV-2 infections and fatality data were collected from the Institute of Epidemiology Disease Control and Research (IEDCR), Bangladesh. The average IFR was calculated from the monthly COVID-19 cases and population size while average CFR was calculated from the number of monthly deaths and number of confirmed COVID-19 cases. Results: SARS-CoV-2 first emerged in Bangladesh on March 3, 2020 and created three pandemic waves so far. The phylogenetic analysis revealed multiple introductions of SARS-CoV-2 variant(s) into Bangladesh with at least 22 Nextstrain clades and 107 Pangolin lineages with respect to the SARS-CoV-2 reference genome of Wuhan/Hu-1/2019. The Delta variant was detected as the most predominant (48.06%) variant followed by Omicron (27.88%), Beta (7.65%), Alpha (1.56%), Eta (0.33%) and Gamma (0.03%) variant. The overall IFR and CFR from circulating variants were 13.59% and 1.45%, respectively. A time-dependent monthly analysis showed significant variations in the IFR (p = 0.012, Kruskal-Wallis test) and CFR (p = 0.032, Kruskal-Wallis test) throughout the study period. We found the highest IFR (14.35%) in 2020 while Delta (20A) and Beta (20H) variants were circulating in Bangladesh. Remarkably, the highest CFR (1.91%) from SARS-CoV-2 variants was recorded in 2021. Conclusion: Our findings highlight the importance of genomic surveillance for careful monitoring of variants of concern emergence to interpret correctly their relative IFR and CFR, and thus, for implementation of strengthened public health and social measures to control the spread of the virus. Furthermore, the results of the present study may provide important context for sequence-based inference in SARS-CoV-2 variant(s) evolution and clinical epidemiology beyond Bangladesh.

8.
Eur J Epidemiol ; 27(8): 581-91, 2012 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-22961293

RESUMEN

Available literature suggests that both vitamin D and calcium may be associated with a wide range of non-skeletal outcomes. However, epidemiological evidence supporting their individual associations with incident cerebrovascular disease is scarce. We conducted a systematic review and meta-analysis of prospective cohort studies, published before February 2012 and sought from MEDLINE, EMBASE, BIOSIS and the Science Citation Index databases, and reported cerebrovascular disease (defined as any fatal or non-fatal ischemic stroke, hemorrhagic stroke, cerebrovascular accident or transient ischemic attack) by circulating vitamin D (25-hydroxy vitamin D [25(OH)D] as active metabolite) and calcium levels. Two independent investigators abstracted information on 25(OH)D and calcium, cerebrovascular outcomes and other characteristics from selected studies. Relative risks (RRs) were pooled by both random and fixed effects meta-analyses and were further examined under different study-level characteristics. Publication bias was assessed with funnel plots and Egger's asymmetry test. From 5,778 initial references, nine unique prospective cohort studies met our inclusion criteria. Seven studies (involving 47,809 participants and 926 cerebrovascular events) focused on circulating 25(OH)D and 3 reported on circulating calcium (22,577 participants and 727 events). For 25(OH)D, in a comparison of individuals in the top third versus those in the bottom third at baseline, the combined RR for cerebrovascular disease, adjusted for several conventional risk factors, was 0.60 (95 % CI 0.48, 0.72). The corresponding RR in the prospective studies that reported on baseline circulating calcium levels for cerebrovascular disease was 1.40 (95 % CI 1.19, 1.64). There was no apparent evidence of heterogeneity or publication bias among included studies. Available data indicate that higher circulating level of vitamin D is associated with a decreased risk of cerebrovascular disease. Conversely, higher circulating calcium concentration is associated with an increased risk of cerebrovascular disease.


Asunto(s)
Calcio de la Dieta/sangre , Trastornos Cerebrovasculares/sangre , Vitamina D/sangre , Vitaminas/sangre , Calcio/administración & dosificación , Calcio/sangre , Calcio de la Dieta/administración & dosificación , Trastornos Cerebrovasculares/prevención & control , Humanos , Factores de Riesgo , Vitamina D/administración & dosificación , Vitaminas/administración & dosificación
9.
Ophthalmic Genet ; 43(2): 191-200, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-34751623

RESUMEN

BACKGROUND: The diagnosis of retinal dystrophies can be challenging due to the spectrum of protean phenotypic manifestations. This study employed trio-whole-exome sequencing (trio-WES) to unveil the genetic cause of an inherited retinal disorder in a south Indian family. MATERIALS AND METHODS: Proband's initial ophthalmic examinations was performed in the year 2016. WES was performed on a proband-parent trio to identify causative mutation followed by Sanger validation, segregation analysis, sequence and structure-based computational analysis to assess its pathogenicity. Based on the genetic findings, detailed clinical reassessments were performed in year 2020 for the proband and available family members. RESULTS: WES revealed a novel homozygous BEST1 mutation c.G310A (p.D104N) in the proband and heterozygous for the parents, indicating autosomal recessive inheritance. Segregation analysis showed heterozygous mutation in maternal grandfather and normal genotype for younger brother and maternal grandmother. Moreover, the structure-based analysis revealed the mutation p.D104N in the cytoplasmic domain, causing structural hindrance by altering hydrogen bonds and destabilizing the BEST1 protein structure. Proband's clinical assessments were consistent with autosomal recessive bestrophinopathy (ARB) phenotype. Additionally, characteristic absent light rise and decreased light peak-to-dark trough ratio (LP:DT) was observed bilaterally in EOG. CONCLUSIONS: Our study demonstrates the utility of WES and clinical re-evaluations in establishing the precise diagnosis of autosomal recessive bestrophinopathy associated with a novel mutation, thus expanding the BEST1-related mutation spectrum.


Asunto(s)
Anomalías del Ojo , Distrofias Retinianas , Antagonistas de Receptores de Angiotensina , Inhibidores de la Enzima Convertidora de Angiotensina , Bestrofinas/genética , Canales de Cloruro/genética , Electrorretinografía , Enfermedades Hereditarias del Ojo , Proteínas del Ojo/genética , Humanos , Masculino , Mutación , Linaje , Fenotipo , Enfermedades de la Retina , Secuenciación del Exoma
10.
Int J Emerg Med ; 14(1): 54, 2021 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-34525945

RESUMEN

BACKGROUND: Bystander cardiopulmonary resuscitation (CPR) rates remain fairly low through most communities despite multiple interventions through the years. Understanding the attitudes and fears behind CPR training and performance would help target education and training to raise the rates of bystander CPR and consequently survival rates of victims. 7909 participants at a single-day mass CPR training session in Singapore were given survey questionnaires to fill out. 6473 people submitted completed forms upon the conclusion of the training session. Some issues looked at were the overall level of difficulty of CPR, difficulty levels of specific skills, attitudes towards refresher training, attitudes towards performing CPR, and fears when doing so. RESULTS: The mean level of difficulty of CPR was rated 3.98 (scale of 1-10), with those with previous CPR training rating it easier. The skills rated most difficult were performing mouth-to-mouth breathing and chest compressions, while the easiest rated was recognizing non-responsiveness. A majority (69.7%) would agree to go for refresher training every 2 years and 88.7% felt everyone should be trained in CPR. 71.6% would perform full CPR for a member of the public in cardiac arrest and only 20.7% would prefer to only do chest compressions. The most cited fear was a low level of confidence, and fears of acquiring infections or aversion to mouth-to-mouth breathing were low. CONCLUSIONS: The survey results show that most participants in Singapore are keen to perform conventional CPR for a member of the public and can help to target future CPR training accordingly.

11.
Biochim Biophys Acta Gen Subj ; 1865(11): 129993, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-34453987

RESUMEN

BACKGROUND: Low pH induced nucleic acid polymorphism and the interaction of naturally occurring small molecules with different polymorphic forms of DNA have been the focus in developing new drugs. Recent studies have revealed that low pH plays an active role in growth and development of cancer cells. Our target is to find whether and how the indoloquinoline alkaloid cryptolepine (CRP) interact with different polymorphic forms of natural DNA, in hope to explore this group of alkaloids as new therapeutics. METHODS: Multiple spectroscopic techniques that include UV-visible absorption spectrophotometry, fluorimetry, CD spectroscopy along with thermal melting studies were employed to characterize the interaction between the alkaloid cryptolepine with the B and protonated forms of DNA. RESULTS & CONCLUSIONS: Cryptolepine has been found to interact with either forms of DNA. The nature of binding is non-cooperative in both cases. Data show that the affinity of CRP to B form of DNA is relatively higher than that for the protonated form of DNA. Circular dichroic studies reveal that the alkaloid converts the left handed protonated DNA into bound right handed form. Fluorescence quenching experiments reveal that cryptolepine intercalates within the DNA base pairs. Thermal melting studies show that the alkaloid stabilises the DNA structures. GENERAL SIGNIFICANCE: Such non-B DNA structures are often present at the 'mutation hotspots' that are associated with genetic instability related diseases such as cancer. The ability of cryptolepine to interact to such non-B DNA structures makes it a useful substrate in the designing of potential chemotherapeutic agents.


Asunto(s)
ADN/química , Alcaloides Indólicos/química , Quinolinas/química , Sitios de Unión , Dicroismo Circular , Fluorometría , Estructura Molecular , Protones , Espectrofotometría Ultravioleta
12.
Spectrochim Acta A Mol Biomol Spectrosc ; 246: 119008, 2021 Feb 05.
Artículo en Inglés | MEDLINE | ID: mdl-33038855

RESUMEN

Single stranded polyriboadenylic acid [poly (rA)] has been accepted widely as a suitable drug target owing to its vital role in the development of cancer since it controls gene expression during cell growth and differentiation. The biological properties of poly (rA) depend on its structural morphology. Pharmacologically active flavonoids can act as suitable binders to poly (rA) and significantly change its biophysical properties. Different factors favour flavonoid-poly (rA) binding. In our present work we have explored the role played by the position of hydroxyl groups in the flavonoids namely 3, 5, 6 and 7 hydroxyflavones in their course of interaction with poly (rA). A range of spectroscopic experiments reveal that 3HF binds best to poly (rA) among the four chosen flavonoids. This is probably due to the presence of a hydroxyl group in '3' position that enables it to exhibit ESIPT phenomenon which is missing for the other used flavonoids.


Asunto(s)
Flavonoides , Poli A , Fenómenos Biofísicos , Análisis Espectral
13.
Spectrochim Acta A Mol Biomol Spectrosc ; 225: 117513, 2020 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-31521000

RESUMEN

The use of bioactive flavonoids as drugs has long mesmerized the scientific world. Their small size and planar structure enables them to interact with limitless substrates especially biomolecules. Taxifolin is a flavonoid well known for its anti-oxidizing and metal chelating properties. Its interaction with a few biomolecules has been studied so far to exploit its pharmacological activities. Hemoglobin, an iron containing macromolecule acts as a major carrier protein and is also associated with the occurrence of many diseases. Our present study lays emphasis on the interaction of flavanonol taxifolin with bovine hemoglobin at physiological pH. This was achieved by monitoring the changes in the absorbance, fluorescence, anisotropic, lifetime and circular dichroic spectra. Benesi-Hildebrand plot determined a binding constant value of 20.0 × 103 M-1 at 25 °C. Stern-Volmer quenching studies reveal that the binding is associated with a static mode of quenching. The complexation is thermodynamically favored as indicated by the negative value of enthalpy and positive value of entropy changes seen from the van't Hoff plot. Theoretical DFT calculations were used to find out an optimized geometry and HOMO-LUMO energy gap for taxifolin. Molecular docking studies revealed the location of taxifolin inside the hemoglobin moiety.


Asunto(s)
Hemoglobinas/química , Hemoglobinas/metabolismo , Quercetina/análogos & derivados , Animales , Sitios de Unión , Bovinos , Dicroismo Circular , Polarización de Fluorescencia , Concentración de Iones de Hidrógeno , Técnicas In Vitro , Simulación del Acoplamiento Molecular , Unión Proteica , Conformación Proteica , Quercetina/química , Quercetina/metabolismo , Espectrometría de Fluorescencia , Análisis Espectral/métodos , Termodinámica
14.
Spectrochim Acta A Mol Biomol Spectrosc ; 223: 117293, 2019 Dec 05.
Artículo en Inglés | MEDLINE | ID: mdl-31260885

RESUMEN

The association of a putative bioactive alkaloid nitidine (NIT) with blood protein bovine hemoglobin (BHb) was investigated by employing various biophysical and molecular docking techniques. NIT binding to BHb was first characterized by hypochromic effect on the Soret band absorption of BHb from spectrophotometric studies. Spectrofluorimetric titration and unchanged fluorescence lifetime of BHb confirmed ground state complexation followed by the static nature of the emission quenching mechanism of the protein induced by NIT. Substantial conformational changes in the protein structure were established from circular dichroism study. Conformational perturbation results a lowering in the α-helical organization of the tetrameric protein structure. Thermodynamics of the binding suggest that the binding is exothermic with a favourable small positive entropy change and negative enthalpy change making a sense of electrostatic interaction as the major acting force. Experimentally calculated free energy change for the NIT-BHb interaction was found to be -7.50 kcal mol-1 which is in well agreement to the theoretical docking energy value of -6.36 kcal mol-1. AutoDock based molecular docking suggests the internal cavity of BHb as the preferred binding position of NIT. Overall this manuscript depicts consequences on the molecular interaction of NIT with BHb from structural and energetic standpoints providing a profound insight into protein-ligand association.


Asunto(s)
Alcaloides/química , Alcaloides/metabolismo , Benzofenantridinas/química , Benzofenantridinas/metabolismo , Hemoglobinas/metabolismo , Animales , Sitios de Unión , Bovinos , Dicroismo Circular , Cinética , Conformación Molecular , Simulación del Acoplamiento Molecular , Unión Proteica , Espectrometría de Fluorescencia , Espectrofotometría Ultravioleta , Termodinámica , Triptófano/química
15.
Int J Biol Macromol ; 138: 57-69, 2019 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-31301395

RESUMEN

Chelerythrine (CHL) is a pharmacologically important molecule that appears in positively charged iminium and neutral alkanolamine form on varying the pH. Association of bovine hemoglobin (BHb) with iminium and alkanolamine forms of CHL is explored employing several spectroscopic and theoretical tools. Our results revealed that iminium form of CHL shows greater binding affinity than the neutral alkanolamine form, with nearly one binding site on the protein for both forms. Thermodynamic data showed that the iminium binding to BHb was characterized by negative enthalpy and positive entropy changes while the association of the alkanolamine CHL was accompanied with both positive enthalpy and entropy changes. Both forms of CHL have been found to quench the intrinsic fluorescence of BHb. From Förster's resonance energy transfer (FRET) studies, the binding distance between the energy acceptor (CHL) and donor (ß-Trp 37 of BHb) was found to be optimum for fluorescence quenching to occur. The conformational transformation of BHb induced by CHL complexation showed greater unfolding of the protein architecture for the iminium interaction from CD spectroscopy. Molecular docking study revealed that both iminium and alkanolamine form of CHL reside near ß-Trp 37 at the α1ß2 interface of BHb.


Asunto(s)
Benzofenantridinas/metabolismo , Hemoglobinas/metabolismo , Simulación del Acoplamiento Molecular , Animales , Bovinos , Transferencia de Energía , Hemoglobinas/química , Concentración de Iones de Hidrógeno , Unión Proteica , Conformación Proteica , Termodinámica
16.
Polymers (Basel) ; 11(2)2019 Jan 23.
Artículo en Inglés | MEDLINE | ID: mdl-30960181

RESUMEN

Recently, we have developed an eco-friendly method for the preparation of a renewable dicarboxylic acid 2,5-furandicarboxylic acid (FDCA) from biomass-based 5-hydroxymethylfrufural (HMF). In the present work, we optimized our reported method, which used phosphate buffer and Fe(OH)3 as the stabilizer to improve the stability of potassium ferrate, then got a purified FDCA (up to 99%) in high yield (91.7 wt %) under mild conditions (25 °C, 15 min, air atmosphere). Subsequently, the obtained FDCA, along with 1,6-hexanediol (HDO), which was also made from HMF, were used as monomers for the synthesis of poly(hexylene 2,5-furandicarboxylate) (PHF) via direct esterification, and triphenyl phosphite was used as the antioxidant to alleviate the discoloration problem during the esterification. The intrinsic viscosity, mechanical properties, molecular structure, thermal properties, and degradability of the PHFs were measured or characterized by Koehler viscometer, universal tensile tester, Nuclear Magnetic Resonance (NMR), Fourier-transform Infrared (FTIR), X-ray diffraction (XRD), Differential Scanning Calorimeter (DSC), Derivative Thermogravimetry (DTG), Scanning Electron Microscope (SEM), and weight loss method. The experimental evidence clearly showed that the furan-aromatic polyesters prepared from biomass-based HMF are viable alternatives to the petrochemical benzene-aromatic polyesters, they can serve as low-melting heat bondable fiber, high gas-barrier packaging material, as well as specialty material for engineering applications.

17.
Bioresour Technol ; 281: 440-448, 2019 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-30876797

RESUMEN

Recently, the worldwide production of dissolving pulp has grown rapidly. Enzymatic technologies play an important role in producing high-quality dissolving pulp, due to their green, mild conditions, high specificity and efficiency. In this review, the relevant publications regarding enzyme applications for dissolving pulp are summarized. Cellulase and xylanase are two major enzymes used for this purpose. Cellulase can improve the quality of dissolving pulp, such as improving the reactivity/accessibility, controlling the intrinsic viscosity and adjusting the molecular weight. Xylanase is mainly used to increase the purity of the dissolving pulp and improve the pulp brightness. Furthermore, in order to increase the enzymatic treatment efficiency, the enzymatic technology can be combined with other techniques, including mechanical refining, fiber fractionations, alkali treatment and use of additives. The advantages, disadvantages and practical implications are analyzed. Also, the potential of other enzymes (such as laccase, mannanase) are discussed.


Asunto(s)
Celulosa/metabolismo , Madera/química , Celulasa/metabolismo , Endo-1,4-beta Xilanasas/metabolismo , Viscosidad
18.
Int J Biol Macromol ; 120(Pt A): 1156-1169, 2018 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-30172817

RESUMEN

Fisetin (FTN) and its metal chelates are critically important since this bioflavonoid possesses wide range of pharmacological properties. Usually, metal binding property enhances the pharmaceutical activity of FTN. Thus in this report, we investigated the complexation of FTN with biologically essential metal ion Cu2+ and further examined the effect of such complexation on calf thymus DNA (CT DNA) binding in comparison with free FTN. We have characterized the complex formation of FTN with Cu2+ using UV-visible, fluorimetric and FTIR studies. Within our experimental concentration range we found that, FTN forms a 2:1 complex with Cu2+ in terms of FTN:Cu2+. Spectroscopic analysis revealed that both FTN and FTN2-Cu2+ complex bind with CT DNA and the binding constant is higher for free FTN. Perturbation of circular dichroism spectrum of CT DNA was observed in presence of free FTN due to structural alteration in DNA double helix. Viscometric, thermal melting and fluorescence quenching study confirm that FTN intercalates in between the base pairs of CT DNA while its Cu (II) complex acts as a groove binder. Molecular docking study further confirms that FTN intercalates into AT rich region of CT DNA while its Cu (II) complex binds at the minor groove.


Asunto(s)
Complejos de Coordinación/química , Cobre/química , ADN/química , Flavonoides/química , Animales , Bovinos , Quelantes/química , Quelantes/metabolismo , Dicroismo Circular , Complejos de Coordinación/metabolismo , Flavonoides/metabolismo , Flavonoles , Simulación del Acoplamiento Molecular , Conformación de Ácido Nucleico/efectos de los fármacos , Agua/química
19.
J Community Genet ; 9(3): 195-199, 2018 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-29470710

RESUMEN

Risk prediction models have a key role in stratified disease prevention, and the incorporation of genomic data into these models promises more effective personalisation. Although the clinical utility of incorporating genomic data into risk prediction tools is increasingly compelling, at least for some applications and disease types, the legal and regulatory implications have not been examined and have been overshadowed by discussions about clinical and scientific utility and feasibility. We held a workshop to explore relevant legal and regulatory perspectives from four EU Member States: France, Germany, the Netherlands and the UK. While we found no absolute prohibition on the use of such data in those tools, there are considerable challenges. Currently, these are modest and result from genomic data being classified as sensitive data under existing Data Protection regulation. However, these challenges will increase in the future following the implementation of EU Regulations on data protection which take effect in 2018, and reforms to the governance of the manufacture, development and use of in vitro diagnostic devices to be implemented in 2022. Collectively these will increase the regulatory burden placed on these products as risk stratification tools will be brought within the scope of these new Regulations. The failure to respond to the challenges posed by the use of genomic data in disease risk stratification tools could therefore prove costly to those developing and using such tools.

20.
Int J Biol Macromol ; 119: 1106-1112, 2018 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-30098360

RESUMEN

Polymorphism of DNA plays a very important part of research relating to the drug-DNA interactions. Here main focus of our investigation is to monitor the interaction of the benzophenanthridine plant alkaloid, nitidine (NIT) with two different forms of DNA i.e. B-DNA and protonated form of DNA maintaining proper temperatures and buffer conditions. Binding interaction of NIT was ascertained from the UV-Visible spectroscopic and spectrofluorimetric titration experiments. Binding constants of the interactions of NIT with different polymorphic forms were calculated from UV-absorption study. The binding constants were 3.8 × 105 M-1 and 1.3 × 105 M-1 for B-DNA and protonated DNA respectively. Red shift in the absorption maxima of NIT on binding with DNA, comparatively greater relative quenching of fluorescence intensity of free NIT than bound NIT, perturbation in the CD spectrum of DNA in presence of NIT confirmed the mode of binding as intercalation. Moreover, spectropolarimetric experiment confirms that left handed protonated form of DNA gets partially converted to the canonical B form of DNA while binds with NIT. Besides the CD experiment, thermal melting experiment also showed that on binding with NIT stabilization of protonated DNA was increased to an appreciable extent.


Asunto(s)
Emparejamiento Base/efectos de los fármacos , Benzofenantridinas/farmacología , ADN/química , Protones , Temperatura , Animales , Bovinos , Concentración de Iones de Hidrógeno , Desnaturalización de Ácido Nucleico , Análisis Espectral
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