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1.
Nucleic Acids Res ; 50(18): 10201-10211, 2022 10 14.
Artigo em Inglês | MEDLINE | ID: mdl-35882385

RESUMO

Ribosomes are remarkable in their malleability to accept diverse aminoacyl-tRNA substrates from both the same organism and other organisms or domains of life. This is a critical feature of the ribosome that allows the use of orthogonal translation systems for genetic code expansion. Optimization of these orthogonal translation systems generally involves focusing on the compatibility of the tRNA, aminoacyl-tRNA synthetase, and a non-canonical amino acid with each other. As we expand the diversity of tRNAs used to include non-canonical structures, the question arises as to the tRNA suitability on the ribosome. Specifically, we investigated the ribosomal translation of allo-tRNAUTu1, a uniquely shaped (9/3) tRNA exploited for site-specific selenocysteine insertion, using single-molecule fluorescence. With this technique we identified ribosomal disassembly occurring from translocation of allo-tRNAUTu1 from the A to the P site. Using cryo-EM to capture the tRNA on the ribosome, we pinpointed a distinct tertiary interaction preventing fluid translocation. Through a single nucleotide mutation, we disrupted this tertiary interaction and relieved the translation roadblock. With the continued diversification of genetic code expansion, our work highlights a targeted approach to optimize translation by distinct tRNAs as they move through the ribosome.


Continued expansion of the genetic code has required the use of synthetic tRNAs for decoding. Some of these synthetic tRNAs have unique structural features that are not observed in canonical tRNAs. Here, the authors applied single-molecule, biochemical and structural methods to determine whether these distinct features were deleterious for efficient protein translation on the ribosome. With a focus on selenocysteine insertion, the authors explored an allo-tRNA with a 9/3 acceptor domain. They observed a translational roadblock that occurred in A to P site tRNA translocation. This block was mediated by a tertiary interaction across the tRNA core, directing the variable arm position into an unfavorable conformation. A single-nucleotide mutation disrupted this interaction, providing flexibility in the variable arm and promoting efficient protein production.


Assuntos
Biossíntese de Proteínas , RNA de Transferência/ultraestrutura , Ribossomos/ultraestrutura , Aminoácidos/genética , Aminoacil-tRNA Sintetases/genética , Nucleotídeos/metabolismo , RNA de Transferência/metabolismo , Ribossomos/metabolismo , Selenocisteína/química
2.
EMBO J ; 38(21): e102226, 2019 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-31609474

RESUMO

Colony collapse disorder (CCD) is a multi-faceted syndrome decimating bee populations worldwide, and a group of viruses of the widely distributed Dicistroviridae family have been identified as a causing agent of CCD. This family of viruses employs non-coding RNA sequences, called internal ribosomal entry sites (IRESs), to precisely exploit the host machinery for viral protein production. Using single-particle cryo-electron microscopy (cryo-EM), we have characterized how the IRES of Israeli acute paralysis virus (IAPV) intergenic region captures and redirects translating ribosomes toward viral RNA messages. We reconstituted two in vitro reactions targeting a pre-translocation and a post-translocation state of the IAPV-IRES in the ribosome, allowing us to identify six structures using image processing classification methods. From these, we reconstructed the trajectory of IAPV-IRES from the early small subunit recruitment to the final post-translocated state in the ribosome. An early commitment of IRES/ribosome complexes for global pre-translocation mimicry explains the high efficiency observed for this IRES. Efforts directed toward fighting CCD by targeting the IAPV-IRES using RNA-interference technology are underway, and the structural framework presented here may assist in further refining these approaches.


Assuntos
Biomimética , Dicistroviridae/fisiologia , Sítios Internos de Entrada Ribossomal/genética , Biossíntese de Proteínas , RNA de Transferência/genética , RNA Viral/genética , Ribossomos/metabolismo , Microscopia Crioeletrônica , Dicistroviridae/ultraestrutura , Humanos , Modelos Moleculares , Conformação de Ácido Nucleico , RNA de Transferência/ultraestrutura , Ribossomos/ultraestrutura
3.
Blood ; 138(17): 1540-1553, 2021 10 28.
Artigo em Inglês | MEDLINE | ID: mdl-34086867

RESUMO

Thalassemia or sickle cell patients with hereditary persistence of fetal hemoglobin (HbF) have an ameliorated clinical phenotype and, in some cases, can achieve transfusion independence. Inactivation via genome editing of γ-globin developmental suppressors, such as BCL11A or LRF/ZBTB7A, or of their binding sites, have been shown to significantly increase expression of endogenous HbF. To broaden the therapeutic window beyond a single-editing approach, we have explored combinations of cis- and trans-editing targets to enhance HbF reactivation. Multiplex mutagenesis in adult CD34+ cells was well tolerated and did not lead to any detectable defect in the cells' proliferation and differentiation, either in vitro or in vivo. The combination of 1 trans and 1 cis mutation resulted in high editing retention in vivo, coupled with almost pancellular HbF expression in NBSGW mice. The greater in vivo performance of this combination was also recapitulated using a novel helper-dependent adenoviral-CRISPR vector (HD-Ad-dualCRISPR) in CD34+ cells from ß-thalassemia patients transplanted to NBSGW mice. A pronounced increase in HbF expression was observed in human red blood cells in mice with established predominant ß0/ß0-thalassemic hemopoiesis after in vivo injection of the HD-Ad-dualCRISPR vector. Collectively, our data suggest that the combination of cis and trans fetal globin reactivation mutations has the potential to significantly increase HbF both totally and on a per cell basis over single editing and could thus provide significant clinical benefit to patients with severe ß-globin phenotype.


Assuntos
Antígenos CD34/genética , Hemoglobina Fetal/genética , Mutagênese , Talassemia beta/genética , Adulto , Animais , Sistemas CRISPR-Cas , Células Cultivadas , Edição de Genes , Terapia Genética , Humanos , Camundongos , Talassemia beta/terapia , gama-Globinas/genética
4.
Curr Diab Rep ; 23(6): 89-101, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-37126189

RESUMO

PURPOSE OF REVIEW: Type 2 diabetes mellitus (T2DM) is one of the leading causes of death and disability in the world. The majority of diabetes deaths (> 80%) occur in low- and middle-income countries, which are predominant in Latin America. Therefore, the purpose of this article is to compare the clinical practice guideline (CPG) for the pharmacological management of T2DM in Latin America (LA) with international reference guidelines. RECENT FINDINGS: Several LA countries have recently developed CPGs. However, the quality of these guidelines is unknown according to the AGREE II tool and taking as reference three CPGs of international impact: American Diabetes Association (ADA), European Diabetes Association (EASD), and Latin American Diabetes Association (ALAD). Ten CPGs were selected for analysis. The ADA scored > 80% on the AGREE II domains and was selected as the main comparator. Eighty percent of LA CPGs were developed before 2018. Only one was not recommended (all domains < 60%). The CPGs in LA have good quality but are outdated. They have significant gaps compared to the reference. There is a need for improvement, as proposing updates every three years to maintain the best available clinical evidence in all guidelines.


Assuntos
Diabetes Mellitus Tipo 2 , Humanos , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/epidemiologia , América Latina/epidemiologia , Fosfatos de Dinucleosídeos
5.
Rev Panam Salud Publica ; 47: e49, 2023.
Artigo em Espanhol | MEDLINE | ID: mdl-36874151

RESUMO

Objective: Identify knowledge about and barriers to effective access to voluntary interruption of pregnancy (VIP), and to sexual and reproductive health (SRH) services in general, among women from Venezuela (Venezuelan migrants and Colombian returnees). Methods: Qualitative study of 20 semi-structured interviews with women from Venezuela who are residents of Barranquilla and who carry out leadership activities in communities or who participate in or benefit from those activities. The interviews included opinions and experiences related to access to VIP, and to SRH in general, as well as suggestions for improving access for migrant women. The relationship between access to these services and the migration process was explored, as well as the role of social organizations. Results: A lack of information on SRH-related rights was identified as the main access barrier to VIP. Other identified barriers were: attitude towards VIP, excessive steps involved in accessing medical care, difficulties in admission to the social security system, lack of training and care in SRH, and xenophobia in hospitals. The interviewees said they did not understand the legal framework in Colombia and did not know the channels for safe abortion care. Conclusions: Despite the efforts of institutions and international cooperation, Venezuelan migrant women in Barranquilla are in a situation of vulnerability due to their lack of access to sexual and reproductive health, including voluntary interruption of pregnancy. Implementing strategies for comprehensive care for migrants will improve current health conditions and the effective enjoyment of SRH-related rights.


Objetivo: Identificar os conhecimentos e as barreiras para o acesso efetivo das mulheres provenientes da Venezuela (migrantes venezuelanas e retornadas colombianas) à interrupção voluntária da gravidez (IVG) e aos serviços de saúde sexual e reprodutiva (SSR) em geral. Métodos: Estudo qualitativo de 20 entrevistas semiestruturadas com mulheres provenientes da Venezuela, residentes em Barranquilla, que atuam na liderança comunitária ou que participam (ou se beneficiam) das atividades. As entrevistas compreenderam as dimensões de opiniões e experiências relacionadas ao acesso à IVG e aos serviços de SSR em geral, e sugestões para melhorar o acesso das mulheres migrantes. Explorou-se a relação do acesso a esses serviços com o processo migratório e o papel das organizações sociais. Resultados: Identificou-se a falta de informações sobre direitos em SSR como a principal barreira para o acesso à IVG. Outras barreiras identificadas foram: atitude em relação à IVG, excesso de burocracia para obter atenção médica, dificuldades para inclusão no sistema de seguridade social, falta de capacitação e atenção em SSR e xenofobia nos hospitais. As entrevistadas declararam desconhecer o enquadramento jurídico na Colômbia e os trâmites para obter atenção ao aborto seguro. Conclusões: Apesar dos esforços institucionais e de cooperação internacional, as mulheres migrantes venezuelanas em Barranquilla estão em situação de vulnerabilidade por falta de acesso aos serviços de SSR, incluindo a IVG. A implementação de estratégias para atenção integral a migrantes possibilitará a melhoria das condições atuais de saúde e a efetiva fruição dos direitos em SSR.

6.
Biopolymers ; 112(4): e23397, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32898299

RESUMO

We present a new structure of a DNA dodecamer obtained in the presence of Ni2+ ions. The DNA forms Ni-guanine cross-links between neighboring molecules. Our results show that an adequate dosage of Ni2+ may help to form well-defined DNA nanostructures. We also compare our structure with other dodecamers which present unique features and also crystallize in trigonal unit cells, strongly influenced by the counterions associated with DNA. In all cases, the DNA duplexes form parallel pseudo-helical columns in the crystal, similar to DNA-protamine and native DNA fibers.


Assuntos
DNA/química , Guanina/química , Níquel/química , Cátions Bivalentes , Cristalografia por Raios X , Humanos , Modelos Moleculares , Conformação de Ácido Nucleico
7.
Int J Clin Pract ; 74(5): e13478, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31927777

RESUMO

OBJECTIVE: The aim of this study was to appraise the methodological quality of published clinical practice guidelines (CPGs) of community-acquired pneumonia (CAP) using AGREE II instrument for further enhancing the CAP CPG development. METHODS: We performed a systematic review of published CPGs on CAP from January 2007 to May 2019. All reviewers independently assessed each CPG using the AGREE II instrument. A standardised score was calculated for each of the six domains. RESULTS: Our search strategy identified 4125 citations but just 18 met our inclusion criteria. Agreement among reviewers was very good: 0.98. The domains that scored better were: "scope and purpose" and "clarity and presentation". Those that scored worse were "editorial independence", and "applicability". According to the AGREE II evaluation for each Guideline, the NICE, IDSA, BTS, SWAB, Korea, Consensur II, Colombian and Peruvian CPGs were the only recommended with no further modifications. In addition, ERS and SEPAR CPGs were recommended with modifications, with lower scores regarding the editorial independence and applicability. CONCLUSION: In conclusion, published CPGs for CAP management vary in quality with a need to improve the methodological and applicability rigour. This could be achieved following the standards for guidelines development and a better emphasis on how to apply CPGs recommendations in clinical practice.


Assuntos
Infecções Comunitárias Adquiridas/terapia , Pneumonia/terapia , Guias de Prática Clínica como Assunto/normas , Algoritmos , Humanos
8.
Epidemiol Infect ; 147: e77, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30869010

RESUMO

Our objective was to determine the frequency of zika (ZIKV), chikungunya (CHIKV) and dengue (DENV) virus coinfection and describe the mortality cases that occurred during the epidemiologic surveillance of the ZIKV epidemic in Colombia. We analysed all cases of suspected ZIKV infection that were reported to the National Institute of Health (October 2015-December 2016). DENV, CHIKV and ZIKV RNA were detected in serum or tissue samples using polymerase chain reaction assay. Medical records of the fatal cases were reviewed. We identified that 23 871 samples were processed. The frequency of viral agents was 439 (1.84%) for DENV, 257 (1.07%) for CHIKV and 10118 (42.38%) for ZIKV. Thirty-four (0.14%) cases of coinfection were identified. The CHIKV-ZIKV coinfection was present in 28 cases (82.3%), DENV-CHIKV in three (8.8%) and DENV-ZIKV in three (8.8%). Seven (20.6%) coinfection cases were fatal (two DENV-CHIKV cases and five CHIKV-ZIKV cases). Two cases were foetal deaths and the others were related to neurological syndrome and sepsis. In conclusion, the frequency of arbovirus coinfection during epidemic of ZIKV was low, and CHIKV-ZIKV coinfection was the most common. Mortality was high among coinfection patients. The role of each virus in the mortality cases of coinfection warrants further studies.


Assuntos
Febre de Chikungunya/epidemiologia , Coinfecção/epidemiologia , Dengue/epidemiologia , Epidemias , Infecção por Zika virus/epidemiologia , Febre de Chikungunya/virologia , Vírus Chikungunya/isolamento & purificação , Coinfecção/virologia , Colômbia/epidemiologia , Dengue/virologia , Vírus da Dengue/isolamento & purificação , Monitoramento Epidemiológico , Zika virus/isolamento & purificação , Infecção por Zika virus/virologia
9.
BMC Infect Dis ; 19(1): 403, 2019 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-31077143

RESUMO

BACKGROUND: Implementation of sputum Gram stain in the initial assessment of community-acquired pneumonia (CAP) patients is still controversial. We performed a systematic review and meta-analysis to investigate the usefulness of sputum Gram stain for defining the etiologic diagnosis of CAP in adult patients. METHODS: We systematically searched the Medline, Embase, Science Direct, Scopus and LILACS databases for full-text articles. Relevant studies were reviewed by at least three investigators who extracted the data, pooled them using a random effects model, and carried out quality assessment. For each bacterium (Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus, and Gram-negative bacilli), pooled sensitivity, specificity, positive and negative likelihood ratios were reported. RESULTS: After a review of 3539 abstracts, 20 articles were included in the present meta-analysis. The studies included yielded 5619 patients with CAP. Pooled sensitivity and pooled specificity of sputum Gram stain were 0.59 (95% CI, 0.56-0.62) and 0.87 (95% CI, 0.86-0.89) respectively for S. pneumoniae, 0.78 (95% CI, 0.72-0.84) and 0.96 (95% CI, 0.94-0.97) for H. influenzae, 0.72 (95% CI, 0.53-0.87) and 0.97 (95% CI, 0.95-0.99) for S. aureus, and 0.64 (95% CI, 0.49-0.77) and 0.99 (95% CI, 0.97-0.99) for Gram-negative bacilli. CONCLUSION: Sputum Gram stain test is sensitive and highly specific for identifying the main causative pathogens in adult patients with CAP. TRIAL REGISTRATION: This study has been registered at PROSPERO International prospective register of systematic reviews under registration no. CRD42015015337 .


Assuntos
Bactérias/isolamento & purificação , Infecções Comunitárias Adquiridas/diagnóstico , Violeta Genciana , Fenazinas , Pneumonia/diagnóstico , Escarro/microbiologia , Coloração e Rotulagem , Bactérias/classificação , Infecções Comunitárias Adquiridas/microbiologia , Haemophilus influenzae , Humanos , Pneumonia/microbiologia , Staphylococcus aureus , Streptococcus pneumoniae
10.
Nucleic Acids Res ; 45(14): 8378-8391, 2017 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-28637278

RESUMO

Trypanosoma brucei, the causative agent of sleeping sickness (Human African Trypanosomiasis, HAT), contains a kinetoplast with the mitochondrial DNA (kDNA), comprising of >70% AT base pairs. This has prompted studies of drugs interacting with AT-rich DNA, such as the N-phenylbenzamide bis(2-aminoimidazoline) derivatives 1 [4-((4,5-dihydro-1H-imidazol-2-yl)amino)-N-(4-((4,5-dihydro-1H-imidazol-2-yl)amino)phenyl)benzamide dihydrochloride] and 2 [N-(3-chloro-4-((4,5-dihydro-1H-imidazol-2-yl)amino)phenyl)-4-((4,5-dihydro-1H-imidazol-2-yl)amino)benzamide] as potential drugs for HAT. Both compounds show in vitro effects against T. brucei and in vivo curative activity in a mouse model of HAT. The main objective was to identify their cellular target inside the parasite. We were able to demonstrate that the compounds have a clear effect on the S-phase of T. brucei cell cycle by inflicting specific damage on the kinetoplast. Surface plasmon resonance (SPR)-biosensor experiments show that the drug can displace HMG box-containing proteins essential for kDNA function from their kDNA binding sites. The crystal structure of the complex of the oligonucleotide d[AAATTT]2 with compound 1 solved at 1.25 Å (PDB-ID: 5LIT) shows that the drug covers the minor groove of DNA, displaces bound water and interacts with neighbouring DNA molecules as a cross-linking agent. We conclude that 1 and 2 are powerful trypanocides that act directly on the kinetoplast, a structure unique to the order Kinetoplastida.


Assuntos
Pareamento de Bases , DNA de Cinetoplasto/genética , Proteínas de Protozoários/genética , Trypanosoma brucei brucei/genética , Tripanossomíase Africana/metabolismo , Animais , Sítios de Ligação/genética , Cristalografia por Raios X , DNA de Cinetoplasto/química , DNA de Cinetoplasto/metabolismo , Humanos , Camundongos , Conformação de Ácido Nucleico , Ligação Proteica , Proteínas de Protozoários/química , Proteínas de Protozoários/metabolismo , Ressonância de Plasmônio de Superfície , Tripanossomicidas/química , Tripanossomicidas/metabolismo , Tripanossomicidas/farmacologia , Trypanosoma brucei brucei/efeitos dos fármacos , Trypanosoma brucei brucei/metabolismo , Tripanossomíase Africana/tratamento farmacológico , Tripanossomíase Africana/parasitologia
11.
An Acad Bras Cienc ; 91(3): e20180860, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31553367

RESUMO

The first cases of Zika virus infection in Colombia were reported and confirmed in October 2015. The objective of the study was estimate the seroprevalence of ZIKV infection during the pre-epidemic phase in Barranquilla, Colombia, and demonstrate the presence of virus before the Colombian Ministry of Health confirmed the first case. We conducted a descriptive study of the seroprevalence of Zika virus in 390 samples obtained from a blood bank located in Barranquilla, Colombia - a city endemic for dengue, and with a recent history of a Chikungunya disease epidemic. The serum pools were tested using Euroimmun ZIKV ELISA kit. Seroprevalence of Zika virus IgG were: May 2015: 0%, June and July 2015: 2.62% (95% CI = 0.28-12.13) and August 2015: 5.35% (95% CI = 1.74-16.74). This brings to our attention the need for extending the surveillance period of this virus in order to adequately assess its teratogenic effects.


Assuntos
Anticorpos Antivirais/sangue , Doadores de Sangue/estatística & dados numéricos , Imunoglobulina G/sangue , Infecção por Zika virus/sangue , Zika virus/imunologia , Colômbia/epidemiologia , Ensaio de Imunoadsorção Enzimática , Humanos , Estudos Soroepidemiológicos
12.
Emerg Infect Dis ; 23(6): 982-984, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28296632

RESUMO

We report the results of pathologic examinations of 2 fetuses from women in Colombia with Zika virus infection during pregnancy that revealed severe central nervous system defects and potential associated abnormalities of the eye, spleen, and placenta. Amniotic fluid and tissues from multiple fetal organs tested positive for Zika virus.


Assuntos
Feto/patologia , Feto/virologia , Defeitos do Tubo Neural/patologia , Esquizencefalia/patologia , Infecção por Zika virus/diagnóstico , Zika virus/isolamento & purificação , Adolescente , Feminino , Humanos , Defeitos do Tubo Neural/virologia , Gravidez , Esquizencefalia/virologia , Adulto Jovem , Infecção por Zika virus/patologia , Infecção por Zika virus/virologia
13.
Lupus ; 25(11): 1217-23, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26921269

RESUMO

OBJECTIVE: The objective of this paper is to compare disease activity and clinical features at diagnosis in male and female patients with systemic lupus erythematosus (SLE). METHODS: This was a cross-sectional study in which every male patient (n = 40) was matched with three female patients of the same age (±5 years) and racial/ethnic group; disease activity as per the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) and disease manifestations at the time of diagnosis were compared. RESULTS: Alopecia and anti-Ro antibodies were more frequent in female patients. No statistically significant difference in any other disease characteristics was found. However, male gender was associated with a risk of severe disease activity at the time of diagnosis (as determined by SLEDAI ≥12 score) independent of age, racial/ethnic group, anti-Ro positivity or time to criteria accrual (OR: 3.11 95% CI, 1.09-8.92; p = 0.035). CONCLUSION: In newly diagnosed SLE patients, male gender is associated with higher disease activity despite the fact that male and female patients seem to experience similar overall disease manifestations.


Assuntos
Anticorpos Antinucleares/metabolismo , Lúpus Eritematoso Sistêmico/diagnóstico , Adulto , Alopecia/diagnóstico , Alopecia/imunologia , Alopecia/metabolismo , Estudos Transversais , Feminino , Humanos , Lúpus Eritematoso Sistêmico/imunologia , Lúpus Eritematoso Sistêmico/metabolismo , Masculino , Índice de Gravidade de Doença , Fatores Sexuais , Adulto Jovem
14.
Euro Surveill ; 21(22)2016 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-27277216

RESUMO

We report clinical features and histopathological findings in fatal cases with dengue (DENV) and chikungunya (CHIKV) co-infection identified at the Colombian National Institute of Health between September 2014 and October 2015. Seven such cases were documented. Dengue serotype 2 virus was identified in six cases. All patients were adults and comorbidities were present in four. Fever, arthralgia or myalgia was present in all cases. The frequency of rash, haemorrhage, oedema, and gastrointestinal symptoms was variable. Laboratory findings such as thrombocytopenia, renal failure, and leukocyte count were also inconsistent between cases. Post-mortem tissue examination documented focal hepatocellular coagulative necrosis in three cases, incipient acute pericarditis in one and tubulointerstitial nephritis in one. This study provides evidence of mortality in patients with DENV and CHIKV co-infection. Fatal cases were characterised by variable clinical and laboratory features. Evaluation of histopathology of autopsy tissues provided evidence of the pathological consequences of the disease.


Assuntos
Febre de Chikungunya/mortalidade , Febre de Chikungunya/patologia , Vírus Chikungunya/isolamento & purificação , Vírus da Dengue/isolamento & purificação , Dengue/mortalidade , Dengue/patologia , Idoso , Idoso de 80 Anos ou mais , Artralgia/epidemiologia , Artralgia/virologia , Autopsia , Febre de Chikungunya/diagnóstico , Vírus Chikungunya/classificação , Vírus Chikungunya/genética , Coinfecção/mortalidade , Coinfecção/virologia , Colômbia/epidemiologia , Dengue/diagnóstico , Vírus da Dengue/classificação , Vírus da Dengue/genética , Feminino , Febre/epidemiologia , Febre/virologia , Humanos , Masculino , Pessoa de Meia-Idade , Mialgia/epidemiologia , Mialgia/virologia , Filogenia , Reação em Cadeia da Polimerase , Estudos Retrospectivos , Análise de Sequência de RNA , Sorogrupo
15.
Acta Crystallogr D Biol Crystallogr ; 71(Pt 7): 1423-32, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26143914

RESUMO

High-mobility group protein 1 (HMGB1) is an essential and ubiquitous DNA architectural factor that influences a myriad of cellular processes. HMGB1 contains two DNA-binding domains, box A and box B, which have little sequence specificity but have remarkable abilities to underwind and bend DNA. Although HMGB1 box A is thought to be responsible for the majority of HMGB1-DNA interactions with pre-bent or kinked DNA, little is known about how it recognizes unmodified DNA. Here, the crystal structure of HMGB1 box A bound to an AT-rich DNA fragment is reported at a resolution of 2 Å. Two box A domains of HMGB1 collaborate in an unusual configuration in which the Phe37 residues of both domains stack together and intercalate the same CG base pair, generating highly kinked DNA. This represents a novel mode of DNA recognition for HMGB proteins and reveals a mechanism by which structure-specific HMG boxes kink linear DNA.


Assuntos
DNA/metabolismo , Domínios HMG-Box , Proteína HMGB1/química , Proteína HMGB1/metabolismo , Sequência de Aminoácidos , Animais , Cristalografia por Raios X , DNA/química , Modelos Moleculares , Dados de Sequência Molecular , Conformação de Ácido Nucleico , Conformação Proteica , Ratos , Alinhamento de Sequência
16.
Biopolymers ; 103(3): 123-33, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25257185

RESUMO

In this work, we explore the influence of different solvents and ions on the crystallization behavior of an all-AT dodecamer d(AATAAATTTATT)2 In all cases, the oligonucleotides are found as continuous columns of stacked duplexes. The spatial organization of such columns is variable; consequently we have obtained seven different crystal forms. The duplexes can be made to crystallize in either parallel or crossed columns. Such versatility in the formation of a variety of crystal forms is characteristic for this sequence. It had not been previously reported for any other sequence. In all cases, the oligonucleotide duplexes have been found to crystallize in the B form. The crystallization conditions determine the organization of the crystal, although no clear local interactions have been detected. Mg(2+) and Ni(2+) can be used in order to obtain compact crossed structures. DNA-DNA interactions in the crystals of our all-AT duplexes present crossovers which are different from those previously reported for mixed sequence oligonucleotides. Our results demonstrate that changes in the ionic atmosphere and the crystallization solvent have a strong influence on the DNA-DNA interactions. Similar ionic changes will certainly influence the biological activity of DNA. Modulation of the crystal structure by ions should also be explored in DNA crystal engineering. Liquid crystals with a peculiar macroscopic shape have also been observed.


Assuntos
Cristalografia por Raios X/métodos , DNA/química , Sequência Rica em At/genética , Cristalização , DNA/genética , Cristais Líquidos , Conformação de Ácido Nucleico
17.
Acta Crystallogr D Biol Crystallogr ; 70(Pt 6): 1614-21, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24914972

RESUMO

The DNA of several pathogens is very rich in AT base pairs. Typical examples include the malaria parasite Plasmodium falciparum and the causative agents of trichomoniasis and trypanosomiases. This fact has prompted studies of drugs which interact with the minor groove of DNA, some of which are used in medical practice. Previous studies have been performed almost exclusively with the AATT sequence. New features should be uncovered through the study of different DNA sequences. In this paper, the crystal structure of the complex of the DNA duplex d(AAAATTTT)2 with the dicationic drug 4,4'-bis(imidazolinylamino)diphenylamine (CD27) is presented. The drug binds to the minor groove of DNA as expected, but it shows two new features that have not previously been described: (i) the drugs protrude from the DNA and interact with neighbouring molecules, so that they may act as cross-linking agents, and (ii) the drugs completely cover the whole minor groove of DNA and displace bound water. Thus, they may prevent the access to DNA of proteins such as AT-hook proteins. These features are also expected for other minor-groove binding drugs when associated with all-AT DNA. These findings allow a better understanding of this family of compounds and will help in the development of new, more effective drugs. New data on the biological interaction of CD27 with the causative agent of trichomoniasis, Trichomonas vaginalis, are also reported.


Assuntos
DNA/química , Difenilamina/análogos & derivados , Imidazolinas/química , Cristalografia por Raios X , Difenilamina/química , Difenilamina/farmacologia , Imidazolinas/farmacologia , Conformação de Ácido Nucleico , Trichomonas vaginalis/efeitos dos fármacos
18.
J Mol Biol ; 436(4): 168423, 2024 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-38185325

RESUMO

In bacteriophage λ lysogens, the λcI repressor is encoded by the leaderless transcript (lmRNA) initiated at the λpRM promoter. Translation is enhanced in rpsB mutants deficient in ribosomal protein uS2. Although translation initiation of lmRNA is conserved in bacteria, archaea, and eukaryotes, structural insight of a lmRNA translation initiation complex is missing. Here, we use cryo-EM to solve the structures of the uS2-deficient 70S ribosome of host E. coli mutant rpsB11 and the wild-type 70S complex with λcI lmRNA and fMet-tRNAfMet. Importantly, the uS2-deficient 70S ribosome also lacks protein bS21. The anti-Shine-Dalgarno (aSD) region is structurally supported by bS21, so that the absence of the latter causes the aSD to divert from the normal mRNA exit pathway, easing the exit of lmRNA. A π-stacking interaction between the monitor base A1493 and A(+4) of lmRNA potentially acts as a recognition signal. Coulomb charge flow, along with peristalsis-like dynamics within the mRNA entrance channel due to the increased 30S head rotation caused by the absence of uS2, are likely to facilitate the propagation of lmRNA through the ribosome. These findings lay the groundwork for future research on the mechanism of translation and the co-evolution of lmRNA and mRNA that includes the emergence of a defined ribosome-binding site of the transcript.


Assuntos
Bacteriófago lambda , Escherichia coli , Iniciação Traducional da Cadeia Peptídica , RNA Mensageiro , Proteínas Repressoras , Subunidades Ribossômicas Maiores de Bactérias , Proteínas Virais Reguladoras e Acessórias , Escherichia coli/genética , Escherichia coli/virologia , Proteínas Ribossômicas/metabolismo , RNA Mensageiro/química , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Bacteriófago lambda/genética , Bacteriófago lambda/metabolismo , Subunidades Ribossômicas Maiores de Bactérias/química , Subunidades Ribossômicas Maiores de Bactérias/metabolismo , Proteínas Repressoras/genética , Proteínas Virais Reguladoras e Acessórias/genética
19.
Environ Pollut ; 350: 124044, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38677462

RESUMO

Phthalates may be associated with an increased risk of cardiometabolic diseases by interfering with glucose and lipid metabolism and by promoting adipogenesis. This study aimed to perform a systematic review and meta-analysis of the association between phthalate exposure and subclinical carotid atherosclerosis, using surrogate markers such as carotid intima-media thickness (IMT) and carotid plaques. The literature search was performed using four databases (Web of Science, Medline, PubMed, and Scopus), and this systematic review includes all available observational studies until July 6th, 2023. The Joanna Briggs Institute critical appraisal tool was used to assess the risk of bias. Meta-analyses were performed, and random effects models were used. Six high-quality cross-sectional studies and 2570 participants aged 12 to 70 were included. Six phthalate metabolites showed significant associations with subclinical carotid atherosclerosis. Exposure to MBzP, ΣDEHP, and MnBP was associated with increased carotid IMT. Exposure to MEP was associated with a higher prevalence of carotid plaques, and MiBP was associated with a lower prevalence. Mixed results were observed for MMP in older adults. The meta-analyses showed a high degree of heterogeneity, and the results are based on single studies. This study accurately describes the evidence of this association to date, suggesting that phthalates are associated with increased carotid IMT and a higher prevalence of carotid plaques. Further research is needed to elucidate this association, as phthalates are still used in the manufacture of everyday products, humans continue to be exposed to them, and atherosclerosis is a public health concern.


Assuntos
Doenças das Artérias Carótidas , Espessura Intima-Media Carotídea , Exposição Ambiental , Ácidos Ftálicos , Humanos , Doenças das Artérias Carótidas/induzido quimicamente , Exposição Ambiental/estatística & dados numéricos , Poluentes Ambientais , Adulto , Idoso , Pessoa de Meia-Idade , Criança , Adolescente , Adulto Jovem , Estudos Transversais
20.
Prim Care Diabetes ; 2024 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-38862312

RESUMO

AIMS: To assess the association between sociodemographic and clinical factors with body mass index (BMI) in a population at risk of type 2 diabetes (T2D) in Bogotá and Barranquilla, Colombia. METHODS: This cross-sectional study used data from the PREDICOL Study. Participants with a FINDRISC ≥ 12 who underwent an Oral Glucose Tolerance Test (OGTT) were included in the study (n=1166). The final analytical sample size was 1101 participants. Those with missing data were excluded from the analysis (n=65). The main outcome was body mass index (BMI), which was categorized as normal, overweight, and obese. We utilized unadjusted and adjusted ordinal logistic regression analysis to calculate odds ratios (OR) and 95 % confidence intervals (CI). RESULTS: The prevalence of overweight and obesity was 41 % (n=449) and 47 % (n=517), respectively. Participants with a 2-hour glucose ≥139 mg/dl had 1.71 times higher odds of being overweight or obese (regarding normal weight) than participants with normal 2-hour glucose values. In addition, being a woman, waist circumference altered, and blood pressure >120/80 mmHg were statistically significantly associated with a higher BMI. CONCLUSION: Strategies to control glycemia, blood pressure, and central adiposity are needed in people at risk of T2D. Future studies should be considered with a territorial and gender focus, considering behavioral, and sociocultural patterns.

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