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1.
J Glob Health ; 14: 04098, 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38721686

RESUMO

Background: Emergency obstetric and newborn care (EmONC) in Bangladesh focusses on maternal health, whereby it addresses childbirth and postpartum complications to ensure women's health and well-being. It was transitioned to a digital platform to overcome challenges with the paper-based EmONC register and we conducted implementation research to assess the outcome. Here we outline the stakeholder engagement process integral to the implementation research process. Methods: We adopted a four-step stakeholder engagement model based on the identification, sensitisation, involvement, and engagement of stakeholders. The approach was informed by previous experience, desk reviews, and expert consultations to ensure comprehensive engagement with stakeholders at multiple levels. Led by the Maternal Health Programme of the Government of Bangladesh, we involved high-power and high-interest stakeholders in developing a joint action plan for digitisation of the paper-based EmONC register. Finally, we demonstrated this digital EmONC register in real-life settings to stakeholders at different levels. Results: The successful demonstration process fostered government ownership and collaboration with multiple stakeholders, while laying the foundation for scalability and sustainability. Nevertheless, our experience highlighted that the stakeholder engagement process is context-driven, time-consuming, resource-intensive, iterative, and dynamic, and it requires involving stakeholders with varied expertise. Effective strategic planning, facilitation, and the allocation of sufficient time and resources are essential components for successful stakeholder engagement. Conclusions: Our experience demonstrates the potential of adopting the 'identification, sensitisation, involvement, and engagement' stakeholder engagement model. Success in implementing this model in diverse settings depends on leveraging knowledge gained during implementation, maintaining robust communication with stakeholders, and harnessing the patience and determination of the facilitating organisation.


Assuntos
Participação dos Interessados , Humanos , Bangladesh , Feminino , Gravidez , Recém-Nascido , Serviços de Saúde Materna/organização & administração , Sistema de Registros , Serviços Médicos de Emergência/organização & administração
2.
J Glob Health ; 14: 04086, 2024 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-38751318

RESUMO

Background: It is imperative to maintain accurate documentation of clinical interventions aimed at enhancing the quality of care for newborns and sick children. The National Newborn Health and IMCI programme of Bangladesh led the development of a standardised register for managing newborns and sick children under five years of age during inpatient care through stakeholder engagement. We aimed to assess the implementation outcomes of the standardised register in the inpatient department. Methods: We conducted implementation research in two district hospitals and two sub-district hospitals of Kushtia and Dinajpur districts from November 2022 to January 2023 to assess the implementation outcomes of the standardised register. We assessed the following World Health Organization implementation outcome variables: usability, acceptability, adoption (actual use), fidelity (completeness and accuracy), and utility (quality of care) of the register against preset benchmarks. We collected data through structured interviews with health care providers; participant enrolment; and data extraction from inpatient registers and case record forms. Results: The average usability and acceptability scores among health care providers were 73 (standard deviation (SD) = 14) and 82 (SD = 14) out of 100, respectively. The inpatient register recorded 96% (95% confidence interval (CI) = 95-97) of under-five children who were admitted to the inpatient department (adoption - actual use). The proportions of completed data elements in the inpatient register were above the preset benchmark of 70% for all the assessed data elements except 'investigation done' (24%; 95% CI = 23-26) (fidelity - completeness). The percentage agreements between government-appointed nurses posted and study-appointed nurses were above the preset benchmark of 70% for all the reported variables (fidelity - accuracy). The kappa coefficient for the overall level of agreement between these two groups regarding reported variables indicated moderate to substantial agreement. The proportion of newborns with sepsis receiving injectable antibiotics was 62% (95% CI = 47-75) (utility - quality of care). We observed some variability in the completeness and accuracy of the inpatient register by district and facility type. Conclusions: The inpatient register was positively received by health care providers, with evaluations of implementation outcome variables showing encouraging results. Our findings could inform evidence-based decision-making on the implementation and scale-up of the inpatient register in Bangladesh, as well as other low- and middle-income countries.


Assuntos
Sistema de Registros , Humanos , Bangladesh , Recém-Nascido , Lactente , Pré-Escolar , Instalações de Saúde/normas , Hospitalização/estatística & dados numéricos , Pacientes Internados/estatística & dados numéricos , Qualidade da Assistência à Saúde
3.
NAR Cancer ; 6(2): zcae016, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38596431

RESUMO

With its ligand estrogen, the estrogen receptor (ER) initiates a global transcriptional program, promoting cell growth. This process involves topoisomerase 2 (TOP2), a key protein in resolving topological issues during transcription by cleaving a DNA duplex, passing another duplex through the break, and repairing the break. Recent studies revealed the involvement of various DNA repair proteins in the repair of TOP2-induced breaks, suggesting potential alternative repair pathways in cases where TOP2 is halted after cleavage. However, the contribution of these proteins in ER-induced transcriptional regulation remains unclear. We investigated the role of tyrosyl-DNA phosphodiesterase 2 (TDP2), an enzyme for the removal of halted TOP2 from the DNA ends, in the estrogen-induced transcriptome using both targeted and global transcription analyses. MYC activation by estrogen, a TOP2-dependent and transient event, became prolonged in the absence of TDP2 in both TDP2-deficient cells and mice. Bulk and single-cell RNA-seq analyses defined MYC and CCND1 as oncogenes whose estrogen response is tightly regulated by TDP2. These results suggest that TDP2 may inherently participate in the repair of estrogen-induced breaks at specific genomic loci, exerting precise control over oncogenic gene expression.

4.
Heliyon ; 9(8): e19039, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37636391

RESUMO

Major malnutrition in Bangladesh is zinc (Zn) and iron (Fe) deficiency as most people commonly depend on cereals, chiefly rice and wheat. The main objectives are to enhance Zn and Fe concentrations through the use of selected varieties and the application of respective fertilizers. Field experiments were conducted at Bangladesh Agricultural University (BAU) farm, Mymensingh (AEZ 9, non-calcareous soil) and at Bangladesh Institute of Nuclear Agriculture (BINA) substation, Ishwardi (AEZ 11, calcareous soil) for two consecutive wheat seasons (2014-15 and 2015-16) with 10 varieties and 15 advanced lines. Varieties BARI Gom 25, 27, 28 & 29 and breeding lines Vijay, HPYT-5, 15 & 21 and BL-1883 have been recognized as Zn-enriched wheat varieties (24-30 µg g-1). Among the genotypes, Zn further increased by 4-8 µg g-1 due to Zn fertilization. Concerning Fe-enriched wheat genotypes (24-30 µg g-1), five varieties viz. Shatabdi, Prodip, BARI Gom 25 & 28 and Sufi, and four lines such as HPYT-12, BL-1883, BL-1040 and Fery-60 have been identified. The grain Fe concentration of wheat genotypes increased when Fe was added, the increment being 6-12 µg g-1. A positive relationship between Zn and N is observed with increased protein content. The grain yield of wheat was increased by 3.8-25.7% due to Zn application over the varieties and locations but Fe addition had no effect. The result of the current study showed that a potential breeding line with appropriate fertilization can improve Zn and Fe levels in wheat grain, without incurring loss to wheat yield.

5.
Nat Commun ; 14(1): 311, 2023 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-36658148

RESUMO

Antibody-mediated immunity plays a crucial role in protection against SARS-CoV-2 infection. We isolated a panel of neutralizing anti-receptor-binding domain (RBD) antibodies elicited upon natural infection and vaccination and showed that they recognize an immunogenic patch on the internal surface of the core RBD, which faces inwards and is hidden in the "down" state. These antibodies broadly neutralize wild type (Wuhan-Hu-1) SARS-CoV-2, Beta and Delta variants and some are effective against other sarbecoviruses. We observed a continuum of partially overlapping antibody epitopes from lower to upper part of the inner face of the RBD and some antibodies extend towards the receptor-binding motif. The majority of antibodies are substantially compromised by three mutational hotspots (S371L/F, S373P and S375F) in the lower part of the Omicron BA.1, BA.2 and BA.4/5 RBD. By contrast, antibody IY-2A induces a partial unfolding of this variable region and interacts with a conserved conformational epitope to tolerate all antigenic variations and neutralize diverse sarbecoviruses as well. This finding establishes that antibody recognition is not limited to the normal surface structures on the RBD. In conclusion, the delineation of functionally and structurally conserved RBD epitopes highlights potential vaccine and therapeutic candidates for COVID-19.


Assuntos
Anticorpos Neutralizantes , Anticorpos Antivirais , COVID-19 , Glicoproteína da Espícula de Coronavírus , Humanos , Epitopos , SARS-CoV-2 , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/imunologia
6.
Cell Rep ; 42(1): 111909, 2023 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-36640339

RESUMO

ATM gene mutation carriers are predisposed to estrogen-receptor-positive breast cancer (BC). ATM prevents BC oncogenesis by activating p53 in every cell; however, much remains unknown about tissue-specific oncogenesis after ATM loss. Here, we report that ATM controls the early transcriptional response to estrogens. This response depends on topoisomerase II (TOP2), which generates TOP2-DNA double-strand break (DSB) complexes and rejoins the breaks. When TOP2-mediated ligation fails, ATM facilitates DSB repair. After estrogen exposure, TOP2-dependent DSBs arise at the c-MYC enhancer in human BC cells, and their defective repair changes the activation profile of enhancers and induces the overexpression of many genes, including the c-MYC oncogene. CRISPR/Cas9 cleavage at the enhancer also causes c-MYC overexpression, indicating that this DSB causes c-MYC overexpression. Estrogen treatment induced c-Myc protein overexpression in mammary epithelial cells of ATM-deficient mice. In conclusion, ATM suppresses the c-Myc-driven proliferative effects of estrogens, possibly explaining such tissue-specific oncogenesis.


Assuntos
Quebras de DNA de Cadeia Dupla , Genes myc , Humanos , Camundongos , Animais , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Reparo do DNA , Estrogênios/farmacologia , Epitélio/metabolismo , Carcinogênese/genética , Proteínas de Ciclo Celular/metabolismo
7.
Life Sci ; 308: 120981, 2022 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-36150465

RESUMO

The emergence of beta-coronavirus SARS-CoV-2 gets entry into its host cells by recognizing angiotensin-converting enzyme 2 (ACE2) and transmembrane serine protease 2 (TMPRESS2) receptors, which are responsible for coronavirus diseases-2019 (COVID-19). Global communities have been affected by COVID-19, especially caused the neurological complications and other critical medical issues. COVID-19 associated complications appear in aged people with underlying neurological states, especially in Parkinson's disease (PD) and Alzheimer's disease (AD). ACE2 receptors abundantly expressed in dopamine neurons may worsen the motor symptoms in PD and upregulates in SARS-CoV-2 infected aged patients' brain with AD. Immune-mediated cytokines released in SARS-CoV-2 infection lead to an indirect immune response that damages the central nervous system. Extreme cytokines release (cytokine storm) occurs due to aberrant immune pathways, and activation in microglial propagates CNS damage in COVID-19 patients. Here, we have explored the pathophysiology, immune responses, and long-term neurological impact on PD and AD patients with COVID-19. It is also a crucial step to understanding COVID-19 pathogenesis to reduce fatal outcomes of neurodegenerative diseases.


Assuntos
COVID-19 , Doenças do Sistema Nervoso , Idoso , Enzima de Conversão de Angiotensina 2 , COVID-19/complicações , Citocinas , Humanos , Imunidade , Doenças do Sistema Nervoso/etiologia , Peptidil Dipeptidase A/metabolismo , SARS-CoV-2 , Serina Proteases
8.
Biomaterials ; 288: 121671, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35953331

RESUMO

Because oral transmission of SARS-CoV-2 is 3-5 orders of magnitude higher than nasal transmission, we investigated debulking of oral viruses using viral trap proteins (CTB-ACE2, FRIL) expressed in plant cells, delivered through the chewing gum. In omicron nasopharyngeal (NP) samples, the microbubble count (based on N-antigen) was significantly reduced by 20 µg of FRIL (p < 0.0001) and 0.925 µg of CTB-ACE2 (p = 0.0001). Among 20 delta or omicron NP samples, 17 had virus load reduced below the detection level of spike protein in the RAPID assay, after incubation with the CTB-ACE2 gum powder. A dose-dependent 50% plaque reduction with 50-100 ng FRIL or 600-800 µg FRIL gum against Influenza strains H1N1, H3N2, and Coronavirus HCoV-OC43 was observed with both purified FRIL, lablab bean powder or gum. In electron micrographs, large/densely packed clumps of overlapping influenza particles and FRIL protein were observed. Chewing simulator studies revealed that CTB-ACE2 release was time/dose-dependent and release was linear up to 20 min chewing. Phase I/II placebo-controlled, double-blinded clinical trial (IND 154897) is in progress to evaluate viral load in saliva before or after chewing CTB-ACE2/placebo gum. Collectively, this study advances the concept of chewing gum to deliver proteins to debulk oral viruses and decrease infection/transmission.


Assuntos
COVID-19 , Vírus da Influenza A Subtipo H1N1 , Influenza Humana , Enzima de Conversão de Angiotensina 2 , Goma de Mascar , Procedimentos Cirúrgicos de Citorredução , Humanos , Vírus da Influenza A Subtipo H3N2 , Proteínas de Plantas , Pós , SARS-CoV-2 , Proteínas Virais
9.
Sci Transl Med ; 14(639): eabm0899, 2022 04 06.
Artigo em Inglês | MEDLINE | ID: mdl-35230146

RESUMO

A major challenge to end the pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is to develop a broadly protective vaccine that elicits long-term immunity. As the key immunogen, the viral surface spike (S) protein is frequently mutated, and conserved epitopes are shielded by glycans. Here, we revealed that S protein glycosylation has site-differential effects on viral infectivity. We found that S protein generated by lung epithelial cells has glycoforms associated with increased infectivity. Compared to the fully glycosylated S protein, immunization of S protein with N-glycans trimmed to the mono-GlcNAc-decorated state (SMG) elicited stronger immune responses and better protection for human angiotensin-converting enzyme 2 (hACE2) transgenic mice against variants of concern (VOCs). In addition, a broadly neutralizing monoclonal antibody was identified from SMG-immunized mice that could neutralize wild-type SARS-CoV-2 and VOCs with subpicomolar potency. Together, these results demonstrate that removal of glycan shields to better expose the conserved sequences has the potential to be an effective and simple approach for developing a broadly protective SARS-CoV-2 vaccine.


Assuntos
Vacinas contra COVID-19 , Polissacarídeos , Glicoproteína da Espícula de Coronavírus , Animais , Anticorpos Neutralizantes , Anticorpos Antivirais , COVID-19/prevenção & controle , Vacinas contra COVID-19/imunologia , Vacinas contra COVID-19/metabolismo , Humanos , Camundongos , Modelos Animais , SARS-CoV-2 , Vacinação
10.
Biomed Pharmacother ; 140: 111772, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34062417

RESUMO

The recent pandemic of novel coronavirus disease (COVID-19) has spread globally and infected millions of people. The quick and specific detection of the nucleic acid of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) remains a challenge within healthcare providers. Currently, quantitative reverse transcription-polymerase chain reaction (RT-qPCR) is the widely used method to detect the SARS-CoV-2 from the human clinical samples. RT-qPCR is expensive equipment and needs skilled personnel as well as lengthy detection time. RT-qPCR limitation needed an alternative healthcare technique to overcome with a fast and cheaper detection method. By applying the principles of CRISPR technology, several promising detection methods giving hope to the healthcare community. CRISPR-based detection methods include SHERLOCK-Covid, STOP-Covid, AIOD-CRISPR, and DETECTR platform. These methods have comparative advantages and drawbacks. Among these methods, AIOD-CRISPR and DETECTR are reasonably better diagnostic methods than the others if we compare the time taken for the test, the cost associated with each test, and their capability of detecting SARS-CoV-2 in the clinical samples. It may expect that the promising CRISPR-based methods would facilitate point-of-care (POC) applications in the CRISPR-built next-generation novel coronavirus diagnostics.


Assuntos
COVID-19/virologia , Sistemas CRISPR-Cas/genética , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas/genética , SARS-CoV-2/genética , Teste para COVID-19/métodos , Humanos , Pandemias/prevenção & controle
11.
Antibiotics (Basel) ; 10(3)2021 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-33803296

RESUMO

Biofilm formation is one of the main causes of increased antibiotic resistance in Acinetobacter baumannii infections. Bacteriophages and their derivatives, such as tail proteins with depolymerase activity, have shown considerable potential as antibacterial or antivirulence agents against bacterial infections. Here, we gained insights into the activity of a capsular polysaccharide (CPS) depolymerase, derived from the tailspike protein (TSP) of φAB6 phage, to degrade A. baumannii biofilm in vitro. Recombinant TSP showed enzymatic activity and was able to significantly inhibit biofilm formation and degrade formed biofilms; as low as 0.78 ng, the inhibition zone can still be formed on the bacterial lawn. Additionally, TSP inhibited the colonization of A. baumannii on the surface of Foley catheter sections, indicating that it can be used to prevent the adhesion of A. baumannii to medical device surfaces. Transmission and scanning electron microscopy demonstrated membrane leakage of bacterial cells treated with TSP, resulting in cell death. The therapeutic effect of TSP in zebrafish was also evaluated and the results showed that the survival rate was significantly improved (80%) compared with that of the untreated control group (10%). Altogether, we show that TSP derived from φAB6 is expected to become a new antibiotic against multi-drug resistant A. baumannii and a biocontrol agent that prevents the formation of biofilms on medical devices.

12.
Cell Rep ; 32(6): 108016, 2020 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-32755598

RESUMO

The influenza virus hemagglutinin (HA) and coronavirus spike (S) protein mediate virus entry. HA and S proteins are heavily glycosylated, making them potential targets for carbohydrate binding agents such as lectins. Here, we show that the lectin FRIL, isolated from hyacinth beans (Lablab purpureus), has anti-influenza and anti-SARS-CoV-2 activity. FRIL can neutralize 11 representative human and avian influenza strains at low nanomolar concentrations, and intranasal administration of FRIL is protective against lethal H1N1 infection in mice. FRIL binds preferentially to complex-type N-glycans and neutralizes viruses that possess complex-type N-glycans on their envelopes. As a homotetramer, FRIL is capable of aggregating influenza particles through multivalent binding and trapping influenza virions in cytoplasmic late endosomes, preventing their nuclear entry. Remarkably, FRIL also effectively neutralizes SARS-CoV-2, preventing viral protein production and cytopathic effect in host cells. These findings suggest a potential application of FRIL for the prevention and/or treatment of influenza and COVID-19.


Assuntos
Antivirais/uso terapêutico , Infecções por Coronavirus/tratamento farmacológico , Fabaceae/química , Infecções por Orthomyxoviridae/tratamento farmacológico , Lectinas de Plantas/uso terapêutico , Pneumonia Viral/tratamento farmacológico , Células A549 , Administração Intranasal , Animais , Antivirais/administração & dosagem , Antivirais/farmacologia , Betacoronavirus/efeitos dos fármacos , COVID-19 , Embrião de Galinha , Chlorocebus aethiops , Cães , Feminino , Humanos , Vírus da Influenza A Subtipo H1N1/efeitos dos fármacos , Células Madin Darby de Rim Canino , Camundongos , Camundongos Endogâmicos BALB C , Pandemias , Lectinas de Plantas/administração & dosagem , Lectinas de Plantas/farmacologia , Ligação Proteica , SARS-CoV-2 , Células Vero , Proteínas do Envelope Viral/metabolismo
13.
Genes Cells ; 25(7): 450-465, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32277721

RESUMO

Androgens stimulate the proliferation of epithelial cells in the prostate by activating topoisomerase 2 (TOP2) and regulating the transcription of target genes. TOP2 resolves the entanglement of genomic DNA by transiently generating double-strand breaks (DSBs), where TOP2 homodimers covalently bind to 5' DSB ends, called TOP2-DNA cleavage complexes (TOP2ccs). When TOP2 fails to rejoin TOP2ccs generating stalled TOP2ccs, tyrosyl DNA phosphodiesterase-2 (TDP2) removes 5' TOP2 adducts from stalled TOP2ccs prior to the ligation of the DSBs by nonhomologous end joining (NHEJ), the dominant DSB repair pathway in G0 /G1 phases. We previously showed that estrogens frequently generate stalled TOP2ccs in G0 /G1 phases. Here, we show that physiological concentrations of androgens induce several DSBs in individual human prostate cancer cells during G1 phase, and loss of TDP2 causes a five times higher number of androgen-induced chromosome breaks in mitotic chromosome spreads. Intraperitoneally injected androgens induce several DSBs in individual epithelial cells of the prostate in TDP2-deficient mice, even at 20 hr postinjection. In conclusion, physiological concentrations of androgens have very strong genotoxicity, most likely by generating stalled TOP2ccs.


Assuntos
Androgênios/toxicidade , Quebras de DNA de Cadeia Dupla , Proteínas de Ligação a DNA/metabolismo , Células Epiteliais/metabolismo , Instabilidade Genômica/genética , Diester Fosfórico Hidrolases/metabolismo , Próstata/metabolismo , Animais , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/genética , Quebra Cromossômica , Reparo do DNA por Junção de Extremidades/efeitos dos fármacos , Reparo do DNA por Junção de Extremidades/genética , Proteínas de Ligação a DNA/genética , Células Epiteliais/efeitos dos fármacos , Pontos de Checagem da Fase G1 do Ciclo Celular/efeitos dos fármacos , Pontos de Checagem da Fase G1 do Ciclo Celular/genética , Instabilidade Genômica/efeitos dos fármacos , Histonas/metabolismo , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Diester Fosfórico Hidrolases/genética , Próstata/efeitos dos fármacos , Neoplasias da Próstata/genética , RNA Interferente Pequeno , Receptores Androgênicos/metabolismo
14.
Indian J Clin Biochem ; 35(1): 72-79, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32071498

RESUMO

Streblus asper Lour., traditionally used for anti-diarrheal effects as like dysentery and diarrhea. The present study aims to prove the anti-diarrheal activities of methanolic extract of leaves of S. asper in animal models. The anti-diarrheal activity was evaluated using castor oil-induced diarrhea and magnesium sulphate-induced diarrhea models whereas anti-motility activities were investigated using gastrointestinal transit test examined in animal models. In castor oil-induced diarrhea model, methanolic extract of S. asper (MESA) at the doses of 100, 200, and 400 mg/kg produced statistically significant (P < 0.001) decreased the number of diarrheal feces of rats against castor oil-induced diarrhea as well as magnesium sulphate-induced diarrhea model also showed the same manner. In gastrointestinal transit test, delayed gastric emptying time decreased significantly (P < 0.001), the propulsion of charcoal meal in the gastrointestinal tract which also showed a dose-dependent manner in rats. The recent study indicates that MESA possesses anti-diarrheal property. The findings represent a rational explanation for its use in traditional medicine for the management of diarrhea management.

15.
Anal Chem ; 91(15): 10335-10342, 2019 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-31290655

RESUMO

Acinetobacter baumannii (A. baumannii) strains are common nosocomial pathogens that can cause infections and can easily become resistant to antibiotics. Thus, analytical methods that can be used to rapidly identify A. baumannii from complex samples should be developed. Tail fiber proteins derived from the tail fibers of bacteriophages can recognize specific bacterial surface polysaccharides. For example, recombinant tail proteins, such as TF2 and TF6 derived from the tail fibers of bacteriophages ϕAB2 and ϕAB6, can recognize A. baumannii clinical isolates M3237 and 54149, respectively. Thus, TF2 and TF6 can be used as probes to target specific A. baumannii strains. Generally, TF2 and TF6 are tagged with a hexahistidine (His6) for ease of purification. Given that His6 possesses specific affinity toward alumina through His6-Al chelation, TF2- and TF6-immobilized alumina-coated magnetic nanoparticles (Fe3O4@Al2O3 MNPs) were generated through chelation under microwave heating (power, 900 W) for 60 s in this study. The as-prepared TF2-Fe3O4@Al2O3 and TF6-Fe3O4@Al2O3 MNPs were used as affinity probes to trap trace A. baumannii M3237 and 54149, respectively, from sample solutions. Matrix-assisted laser desorption/ionization mass spectrometry capable of identifying bacteria on the basis of the obtained fingerprint mass spectra of intact bacteria was used as the detection tool. Results demonstrated that the current approach can be used to distinguish A. baumannii M3237 from A. baumannii 54149 by using TF2-Fe3O4@Al2O3 and TF6-Fe3O4@Al2O3 MNPs as affinity probes. Furthermore, the limits of detection of the current method for A. baumannii M3237 and 54149 are ∼105 and ∼104 cells mL-1, respectively. The feasibility of using the developed method to selectively detect A. baumannii M3237 and 54149 from complex serum samples was demonstrated.


Assuntos
Infecções por Acinetobacter/diagnóstico , Acinetobacter baumannii/isolamento & purificação , Bacteriófagos/metabolismo , Cromatografia de Afinidade/métodos , Nanopartículas de Magnetita/química , Proteínas Recombinantes/metabolismo , Proteínas da Cauda Viral/metabolismo , Humanos , Proteínas Recombinantes/química , Proteínas da Cauda Viral/química
16.
Food Chem ; 136(2): 1038-46, 2013 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-23122160

RESUMO

A new analytical method was developed for dinotefuran and its metabolites, MNG, UF, and DN, in melon using high-performance liquid chromatography (HPLC) coupled with an ultraviolet detector (UVD). Due to shorter wavelength, lower sensitivity to UV detection, and high water miscibility of some metabolites, QuEChERs acetate-buffered version was modified for extraction and purification. Mobile phases with different ion pairing or ionisation agents were tested in different reverse phase columns, and ammonium bicarbonate buffer was found as the best choice to increase the sensitivity of target analytes to the UV detector. After failure of dispersive SPE clean-up with primary secondary amine, different solid phase extraction cartridges (SPE) were used to check the protecting capability of analytes against matrix interference. Finally, samples were extracted with a simple and rapid method using acetonitrile and salts, and purified through C(18)SPE. The method was validated at two spiking levels (three replicates for each) in the matrix. Good recoveries were observed for all of the analytes and ranged between 70.6% and 93.5%, with relative standard deviations of less than 10%. Calibration curves were linear over the calibration ranges for all the analytes with r(2)≥ 0.998. Limits of detection ranged from 0.02 to 0.05 mg kg(-1), whereas limits of quantitation ranged from 0.06 to 0.16 mg kg(-1) for dinotefuran and its metabolites. The method was successfully applied to real samples, where dinotefuran and UF residues were found in the field-incurred melon samples. Residues were confirmed via LC-tandem mass spectrometry (LC-MS/MS) in positive-ion electrospray ionisation (ESI(+)) mode.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Cucurbitaceae/química , Contaminação de Alimentos/análise , Guanidinas/análise , Inseticidas/análise , Nitrocompostos/análise , Resíduos de Praguicidas/análise , Cromatografia Líquida de Alta Pressão/instrumentação , Cucurbitaceae/metabolismo , Guanidinas/isolamento & purificação , Guanidinas/metabolismo , Inseticidas/isolamento & purificação , Inseticidas/metabolismo , Neonicotinoides , Nitrocompostos/isolamento & purificação , Nitrocompostos/metabolismo , Resíduos de Praguicidas/isolamento & purificação , Resíduos de Praguicidas/metabolismo , Extração em Fase Sólida , Espectrometria de Massas em Tandem
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