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1.
Chembiochem ; 25(10): e202400107, 2024 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-38536122

RESUMO

This study characterizes the acceptor specificity of levansucrases (LSs) from Gluconobacter oxydans (LS1), Vibrio natriegens (LS2), Novosphingobium aromaticivorans (LS3), and Paraburkholderia graminis (LS4) using sucrose as fructosyl donor and selected phenolic compounds and carbohydrates as acceptors. Overall, V. natriegens LS2 proved to be the best biocatalyst for the transfructosylation of phenolic compounds. More than one fructosyl unit could be attached to fructosylated phenolic compounds. The transfructosylation of epicatechin by P. graminis LS4 resulted in the most diversified products, with up to five fructosyl units transferred. In addition to the LS source, the acceptor specificity of LS towards phenolic compounds and their transfructosylation products were found to greatly depend on their chemical structure: the number of phenolic rings, the reactivity of hydroxyl groups and the presence of aliphatic chains or methoxy groups. Similarly, for carbohydrates, the transfructosylation yield was dependent on both the LS source and the acceptor type. The highest yield of fructosylated-trisaccharides was Erlose from the transfructosylation of maltose catalyzed by LS2, with production reaching 200 g/L. LS2 was more selective towards the transfructosylation of phenolic compounds and carbohydrates, while reactions catalyzed by LS1, LS3 and LS4 also produced fructooligosaccharides. This study shows the high potential for the application of LSs in the glycosylation of phenolic compounds and carbohydrates.


Assuntos
Biocatálise , Hexosiltransferases , Fenóis , Hexosiltransferases/metabolismo , Hexosiltransferases/química , Fenóis/metabolismo , Fenóis/química , Glicosilação , Especificidade por Substrato , Vibrio/enzimologia , Gluconobacter oxydans/enzimologia , Gluconobacter oxydans/metabolismo , Carboidratos/química
2.
BMC Health Serv Res ; 24(1): 168, 2024 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-38321452

RESUMO

BACKGROUND: Emergency Medical Service (EMS) is a very crucial aspect of the healthcare system in providing urgent management and transportation of patients during emergencies. The sustainability of the services is however greatly impacted by the quality and age of ambulances. While this has led to numerous replacement policy recommendations, the implementations are often limited due to a lack of evidence and financial constraints. This study thus aims to develop a cost-effectiveness model and testing the model by evaluating the cost-effectiveness of 10-year and 15-year compulsory ambulance replacement strategies in public healthcare for the Malaysian Ministry of Health (MOH). METHODS: A Markov model was developed to estimate the cost and outcomes ambulance replacement strategies over a period of 20 years. The model was tested using two alternative strategies of 10-year and 15-year. Model inputs were derived from published literature and local study. Model development and economic analysis were accomplished using Microsoft Excel 2016. The outcomes generated were costs per year, the number of missed trips and the number of lives saved, in addition to the Incremental Cost-Effectiveness Ratio (ICER). One-Way Deterministic Sensitivity Analysis (DSA) and Probabilistic Sensitivity Analysis (PSA) were conducted to identify the key drivers and to assess the robustness of the model. RESULTS: Findings showed that the most expensive strategy, which is the implementation of 10 years replacement strategy was more cost-effective than 15 years ambulance replacement strategy, with an ICER of MYR 11,276.61 per life saved. While an additional MYR 13.0 million would be incurred by switching from a 15- to 10-year replacement strategy, this would result in 1,157 deaths averted or additional live saved per year. Sensitivity analysis showed that the utilization of ambulances and the mortality rate of cases unattended by ambulances were the key drivers for the cost-effectiveness of the replacement strategies. CONCLUSIONS: The cost-effectiveness model developed suggests that an ambulance replacement strategy of every 10 years should be considered by the MOH in planning sustainable EMS. While this model may have its own limitation and may require some modifications to suit the local context, it can be used as a guide for future economic evaluations of ambulance replacement strategies and further exploration of alternative solutions.


Assuntos
Ambulâncias , Serviços Médicos de Emergência , Humanos , Análise Custo-Benefício , Malásia
3.
J Exp Bot ; 74(19): 6006-6022, 2023 10 13.
Artigo em Inglês | MEDLINE | ID: mdl-37358252

RESUMO

In response to changing environmental conditions, plants activate cellular responses to enable them to adapt. One such response is autophagy, in which cellular components, for example proteins and organelles, are delivered to the vacuole for degradation. Autophagy is activated by a wide range of conditions, and the regulatory pathways controlling this activation are now being elucidated. However, key aspects of how these factors may function together to properly modulate autophagy in response to specific internal or external signals are yet to be discovered. In this review we discuss mechanisms for regulation of autophagy in response to environmental stress and disruptions in cell homeostasis. These pathways include post-translational modification of proteins required for autophagy activation and progression, control of protein stability of the autophagy machinery, and transcriptional regulation, resulting in changes in transcription of genes involved in autophagy. In particular, we highlight potential connections between the roles of key regulators and explore gaps in research, the filling of which can further our understanding of the autophagy regulatory network in plants.


Assuntos
Autofagia , Regulação da Expressão Gênica , Autofagia/genética , Processamento de Proteína Pós-Traducional , Homeostase , Vacúolos
4.
Clin Linguist Phon ; 37(4-6): 567-582, 2023 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-36779905

RESUMO

The problem in language comprehension in people with right hemisphere damage (RHD) is more equivocal than people with left hemisphere damage. This study explores the reading and listening comprehension of Cantonese-speaking individuals with RHD, left hemisphere damage, and neurotypical healthy controls using the Cantonese Computerized Revised Token Test (CRTT-Cantonese) adapted from the English CRTT. Eighteen native Cantonese-speaking individuals with RHD, 32 individuals with left hemisphere damage and aphasia (PWA), and 42 healthy controls participated in this study. All the participants completed the Cantonese Aphasia Battery, Hong Kong Oxford Cognitive Screen, the listening comprehension version of CRTT-Cantonese (CRTT-L-Cantonese), and the reading comprehension version of CRTT-Cantonese (CRTT-R-WF-Cantonese) across different sessions. Linear mixed-effect analysis revealed significant differences among the groups in CRTT-Cantonese tests. However, there were no significant difference between CRTT-L-Cantonese and CRTT-R-WF-Cantonese within the PWA, RHD and healthy control groups. Tukey post-hoc pairwise comparisons showed that PWA scored significantly lower than RHD and healthy control groups (p < 0.0001) in both CRTT-L-Cantonese and CRTT-R-WF-Cantonese, and the RHD group scored significantly lower than healthy control group only on the CRTT-R-WF-Cantonese. The results demonstrate that the CRTT-L-Cantonese and CRTT-R-WF-Cantonese differentiate language comprehension abilities among PWA, RHD and healthy control groups. Although the current findings did not show any diversion between reading and listening comprehension in RHD group, this group showed poorer performance in reading comprehension when compared to healthy controls. The latter findings may support the view that the right hemisphere contributes to reading comprehension in Chinese.


Assuntos
Afasia , Compreensão , Humanos , Leitura , Percepção Auditiva , Afasia/psicologia , Encéfalo
5.
Clin Linguist Phon ; 37(4-6): 316-329, 2023 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-35678458

RESUMO

Childhood apraxia of speech (CAS) is a paediatric motor speech disorder. We investigated the lexical tone perception and production abilities of children with CAS and the relationships between the two. Three children with CAS, aged between 3;7 and 5;8, were given the Cantonese Tone Identification Test (CANTIT) and the Hong Kong Cantonese Articulation Test (HKCAT) for assessment of tone perception and production, respectively. Accuracy and error patterns were investigated based on their performance on the two tests. Correlation analysis was performed on children's perception and production scores. Two children scored at the lowest rank on the CANTIT, while one child obtained a Z score of 0. All children scored three standard deviations below the mean on the HKCAT. No statistical differences were found among the six tones with respect to perception accuracy, H(5) = 3.731, p = 0.589. Error analysis showed that children with CAS demonstrated more confusion on perceiving tones compared with TD peers. There were no main effects for task (F(1,2) = 0.040, p = 0.859) or tone (F(5,10 = 0.997, p = 0.467); nor were there task or tone interaction effects on perception versus production accuracy (F(5,10) = 1.772, p = 0.206). Tone perception and production accuracy were not significantly correlated (r2 = 0.181, p = 0.078). Tone perception deficits were evident in two out of three children with CAS, while all children had lexical tone production difficulties. In this small sample, tone production was more universally affected than tone perception.


Assuntos
Percepção da Fala , Fala , Criança , Humanos , Pré-Escolar , Projetos Piloto , Hong Kong , Medida da Produção da Fala
6.
Medicina (Kaunas) ; 59(7)2023 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-37512105

RESUMO

Background and Objectives: This study was conducted to investigate whether Pseudomonas aeruginosa (PA) infections of arteriovenous grafts (AVGs) recur more frequently than other bacterial infections following treatment with revision. Materials and Methods: Operative procedures, including total excision, subtotal excision, and revision, were performed on 60 patients to treat 65 AVG infections. Final outcomes were classified as no infection recurrence, infection recurrence, and death without prior recurrence. In the competing risk setting, the cumulative incidence was estimated using the cumulative incidence function and Gray's test, and the associations between outcomes and different variables were estimated using a subdistribution hazard (SDH) model. Results: Comparing AVG infections with and without recurrence, PA infection was not associated with a higher risk of infection recurrence (p = 0.13); however, the first operative procedure type was associated with infection recurrence (p = 0.04). AVGs with PA infection were associated with a higher total number of surgical interventions (p < 0.05) than AVGs without PA infection. Regarding the cumulative incidences of outcomes, for AVGs treated with subtotal excision or revision, the cumulative incidence of recurrent infection was 3.3-fold higher for those with PA infection than without one year after the first surgery. However, when AVGs were treated with revision alone, the cumulative incidence was 4.1-fold. After excluding AVGs treated with total excision, the SDH model was applied, obtaining a hazard ratio for infection recurrence of 16.05 (p = 0.02) for AVGs with PA infection compared with AVGs without PA infection. No other variables were significantly associated with infection recurrence. Conclusions: For subtotal resection and revision, AVGs infected with PA had a higher recurrence rate than those infected with other species. However, revision surgery may aggravate the recurrence rate.


Assuntos
Derivação Arteriovenosa Cirúrgica , Implante de Prótese Vascular , Infecções por Pseudomonas , Humanos , Implante de Prótese Vascular/efeitos adversos , Grau de Desobstrução Vascular , Derivação Arteriovenosa Cirúrgica/efeitos adversos , Infecções por Pseudomonas/epidemiologia , Infecções por Pseudomonas/cirurgia , Infecções por Pseudomonas/etiologia , Diálise Renal , Estudos Retrospectivos , Resultado do Tratamento , Fatores de Risco
7.
Proc Natl Acad Sci U S A ; 116(44): 22376-22385, 2019 10 29.
Artigo em Inglês | MEDLINE | ID: mdl-31611386

RESUMO

The Highly ABA-Induced 1 (HAI1) protein phosphatase is a central component of drought-related signaling. A screen for HAI1-interacting proteins identified HAI1-Interactor 1 (HIN1), a nuclear protein of unknown function which could be dephosphorylated by HAI1 in vitro. HIN1 colocalization and interaction with serine-arginine rich (SR) splicing factors and appearance of nuclear speckle-localized HIN1 during low water potential (ψw) stress suggested a pre-mRNA splicing-related function. RNA sequencing of Arabidopsis Col-0 wild type identified more than 500 introns where moderate severity low ψw altered intron retention (IR) frequency. Surprisingly, nearly 90% of these had increased splicing efficiency (decreased IR) during stress. For one-third of these introns, ectopic HIN1 expression (35S:HIN1) in unstressed plants mimicked the increased splicing efficiency seen in stress-treated wild type. HIN1 bound to a GAA-repeat, Exonic Splicing Enhancer-like RNA motif enriched in flanking sequence around HIN1-regulated introns. Genes with stress and HIN1-affected splicing efficiency were enriched for abiotic stress and signaling-related functions. The 35S:HIN1 plants had enhanced growth maintenance during low ψw, while hin1 mutants had reduced growth, further indicating the role of HIN1 in drought response. HIN1 is annotated as an MYB/SANT domain protein but has limited homology to other MYB/SANT proteins and is not related to known yeast or metazoan RNA-binding proteins or splicing regulators. Together these data identify HIN1 as a plant-specific RNA-binding protein, show a specific effect of drought acclimation to promote splicing efficiency of IR-prone introns, and also discover HAI1-HIN1 interaction and dephosphorylation that connects stress signaling to splicing regulation.


Assuntos
Proteínas de Arabidopsis/metabolismo , Fator de Iniciação 3 em Eucariotos/metabolismo , Pressão Osmótica , Splicing de RNA , Proteínas de Ligação a RNA/metabolismo , Arabidopsis , Proteínas de Arabidopsis/genética , Secas , Fator de Iniciação 3 em Eucariotos/genética , Regulação da Expressão Gênica de Plantas , Íntrons , Proteínas de Ligação a RNA/genética
8.
Proc Natl Acad Sci U S A ; 116(6): 2354-2363, 2019 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-30670655

RESUMO

The clade A protein phosphatase 2C Highly ABA-Induced 1 (HAI1) plays an important role in stress signaling, yet little information is available on HAI1-regulated phosphoproteins. Quantitative phosphoproteomics identified phosphopeptides of increased abundance in hai1-2 in unstressed plants and in plants exposed to low-water potential (drought) stress. The identity and localization of the phosphoproteins as well as enrichment of specific phosphorylation motifs indicated that these phosphorylation sites may be regulated directly by HAI1 or by HAI1-regulated kinases including mitogen-activated protein kinases, sucrose non-fermenting-related kinase 2, or casein kinases. One of the phosphosites putatively regulated by HAI1 was S313/S314 of AT-Hook-Like10 (AHL10), a DNA-binding protein of unclear function. HAI1 could directly dephosphorylate AHL10 in vitro, and the level of HAI1 expression affected the abundance of phosphorylated AHL10 in vivo. AHL10 S314 phosphorylation was critical for restriction of plant growth under low-water potential stress and for regulation of jasmonic acid and auxin-related gene expression as well as expression of developmental regulators including Shootmeristemless These genes were also misregulated in hai1-2 AHL10 S314 phosphorylation was required for AHL10 complexes to form foci within the nucleoplasm, suggesting that S314 phosphorylation may control AHL10 association with the nuclear matrix or with other transcriptional regulators. These data identify a set of HAI1-affected phosphorylation sites, show that HAI1-regulated phosphorylation of AHL10 S314 controls AHL10 function and localization, and indicate that HAI1-AHL10 signaling coordinates growth with stress and defense responses.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Fosfoproteínas/metabolismo , Proteoma , Proteômica , Estresse Fisiológico , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Expressão Gênica , Fenótipo , Fosfoproteínas/genética , Fosforilação , Proteômica/métodos
9.
Can J Infect Dis Med Microbiol ; 2022: 3196545, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36312589

RESUMO

Staphylococcus aureus is a major human pathogen that produces various virulence factors which promote the binding of bacteria to tissues and medical devices such as vascular access devices, thereby developing a wide range of invasive infections. Vascular access serves as an entry site for S. aureus and elevates the risk of infection in the hemodialysis population. Nevertheless, the distribution of virulence genes in Staphylococcus spp. associated with vascular access infections (VAIs) has not been studied previously. In this study, we determined the relationship between the molecular characteristics and virulence profiles of S. aureus isolates obtained from VAIs. We collected isolates from patients with VAIs between August 2017 and December 2020 and further analyzed the molecular characteristics, antimicrobial resistance profiles, and virulence gene distribution in the isolates. Overall, 15 sequence types (STs), including a new ST (ST6892) and 19 spa types, were identified among the 56 isolates. Of the 53 S. aureus isolates, ST8, ST239, ST45, and ST59 were the predominant STs, whereas ST2250 was the only ST in 3 S. argenteus isolates. ST45-SCCmecIV-t026 (abbreviated as ST45-IV-t026), ST59-V-t437, and ST8-IV-t008 were the predominant clones that belonged to agr type I. All isolates harbored clfB and eno, whereas all S. aureus isolates harbored clfA. In addition, 10 Panton-Valentine leucocidin-positive isolates belonged to ST8 and ST59, with ST8-IV-t008 and ST59-V-t437 being the predominant clones. In brief, the distribution of virulence genes associated with STs may assist in the spread of molecular types of Staphylococcus spp.

10.
Biologicals ; 72: 42-53, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34303595

RESUMO

ABP 798 is a biosimilar to Rituxan® (rituximab reference product [RP]). Non-clinical assessments relevant to the primary and secondary mechanisms of action (MOA) contribute to the totality of the evidence (TOE) in supporting biosimilarity and are critical in providing scientific evidence for extrapolation of indications. Similarity of ABP 798 with rituximab RP was investigated across a range of biological activities which have potential impact on pharmacokinetics and clinical efficacy with non-clinical assessments relevant to MOA such as CD20 internalization, trogocytosis, binding to primary human natural killer (NK) cells as well as the ability to induce antibody-dependent cellular phagocytosis (ADCP) in peripheral blood mononuclear cells. Additionally, in vitro synergy of ABP 798 or RP with chemotherapeutic agents, in vivo xenograft studies in mice, and toxicological assessments in cynomolgus monkeys (including B cell depletion and toxicokinetics) were also conducted. Results from these non-clinical assessments contribute to the TOE supporting the biosimilarity between ABP 798 and rituximab RP across a range of primary and secondary MOAs and support justification for extrapolation to all indications of use for ABP 798 for which the RP is approved.


Assuntos
Antineoplásicos , Medicamentos Biossimilares , Rituximab , Animais , Antineoplásicos/farmacologia , Medicamentos Biossimilares/farmacologia , Humanos , Células Matadoras Naturais/efeitos dos fármacos , Leucócitos Mononucleares/efeitos dos fármacos , Camundongos , Padrões de Referência , Rituximab/farmacologia
11.
Medicina (Kaunas) ; 57(8)2021 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-34441041

RESUMO

Background and Objectives: Compression of the common iliac veins (CIV) is not always associated with lower extremity symptoms. This study analyzed this issue from the perspective of patient venous blood flow changes using quantitative flow magnetic resonance imaging. Materials and Methods: After we excluded patients with active deep vein thrombosis, the mean flux (MF) and mean velocity (MV) of the popliteal vein, femoral vein, and external iliac vein (EIV) were compared between the left and right sides. Results: Overall, 26 of the patients had unilateral CIV compression, of which 16 patients had symptoms. No significant differences were noted in the MF or MV of the veins between the two sides. However, for the 10 patients without symptoms, the EIV MF of the compression side was significantly lower than the EIV MF of the non-compression side (p = 0.04). The receiver operating characteristic curve and chi-squared analyses showed that when the percentage difference of EIV MF between the compression and non-compression sides was ≤-18.5%, the relative risk of associated lower extremity symptoms was 0.44 (p = 0.016). Conclusions: If a person has compression of the CIV, a decrease in EIV blood flow rate on the compression side reduces the rate of symptom occurrence.


Assuntos
Veia Femoral , Veia Ilíaca , Humanos , Veia Ilíaca/diagnóstico por imagem , Imageamento por Ressonância Magnética , Veia Cava Inferior
12.
Nat Mater ; 17(11): 1005-1012, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30353088

RESUMO

Graphene and other two-dimensional materials possess desirable mechanical, electrical and chemical properties for incorporation into or onto colloidal particles, potentially granting them unique electronic functions. However, this application has not yet been realized, because conventional top-down lithography scales poorly for producing colloidal solutions. Here, we develop an 'autoperforation' technique that provides a means of spontaneous assembly for surfaces composed of two-dimensional molecular scaffolds. Chemical vapour deposited two-dimensional sheets can autoperforate into circular envelopes when sandwiching a microprinted polymer composite disk of nanoparticle ink, allowing liftoff into solution and simultaneous assembly. The resulting colloidal microparticles have two independently addressable, external Janus faces that we show can function as an intraparticle array of vertically aligned, two-terminal electronic devices. Such particles demonstrate remarkable chemical and mechanical stability and form the basis of particulate electronic devices capable of collecting and storing information about their surroundings, extending nanoelectronics into previously inaccessible environments.

13.
Plant Cell Environ ; 42(10): 2913-2930, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31314921

RESUMO

Protein phosphorylation is a key signalling mechanism and has myriad effects on protein function. Phosphorylation by protein kinases can be reversed by protein phosphatases, thus allowing dynamic control of protein phosphorylation. Although this may suggest a straightforward kinase-phosphatase relationship, plant genomes contain five times more kinases than phosphatases. Here, we examine phospho-signalling from a protein phosphatase centred perspective and ask how relatively few phosphatases regulate many phosphorylation sites. The most abundant class of plant phosphatases, the protein phosphatase 2Cs (PP2Cs), is surrounded by a web of regulation including inhibitor and activator proteins as well as posttranslational modifications that regulate phosphatase activity, control phosphatase stability, or determine the subcellular locations where the phosphatase is present and active. These mechanisms are best established for the Clade A PP2Cs, which are key components of stress and abscisic acid signalling. We also describe other PP2C clades and illustrate how these phosphatases are highly regulated and involved in a wide range of physiological functions. Together, these examples of multiple layers of phosphatase regulation help explain the unbalanced kinase-phosphatase ratio. Continued use of phosphoproteomics to examine phosphatase targets and phosphatase-kinase relationships will be important for deeper understanding of phosphoproteome regulation.


Assuntos
Proteínas de Plantas/metabolismo , Proteína Fosfatase 2C/metabolismo , Transdução de Sinais/fisiologia , Estabilidade Enzimática , Fosforilação , Proteínas Quinases/metabolismo , Processamento de Proteína Pós-Traducional
14.
Microb Pathog ; 128: 69-74, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30583022

RESUMO

Salmonella is a common foodborne and zoonotic pathogen. Only a few serovars carry a virulence plasmid (pSV), which enhances the pathogenicity of the host. Here, we investigated the pathogenicity roles of the pSVs among wild-type, plasmid-less, and complemented S. Typhimurium, S. Enteritidis S. Choleraesuis in invasion, phagocytosis, and intracellular bacterial survival in human THP-1 cells and cell death patterns by flow cytometry and difference in cell death patterns between pig and human S. Choleraesuis isolates with large pSCVs. Virulence plasmid (pSTV) led to slightly increasing cellular apoptosis for S. Typhimurium; virulence plasmid (pSEV) enhanced apoptosis and necrosis significantly for S. Enteritidis; and pSCV reduced apoptosis significantly for S. Choleraesuis. After complementation, pSTV increased the intracellular survival of pSCV-less Choleraesuis and the cytotoxicity against human THP-1 cells. Using the Cytochalasin D to differentiate the invasion of S. Choleraaesuis and phagocytosis of THP-1 cells determined that pSCV were responsible for invasion and phagocytosis at 0 h and inhibited intracellular replication in THP-1 cells, and pSTV were responsible for invasion and increased intracellular survival for S. Choleraesuis in THP-1 cells. The human isolates with large pSCV induced more cellular apoptosis and necrosis than the pig isolates. In conclusion, human S. Choleraesuis isolates carrying large pSCVs were more adapted to human THP-1 cells for more cell death than pig isolates with large pSCV. The role of pSVs in invasion, phagocytosis, intracellular survival and apoptosis differed among hosted serovars.


Assuntos
Morte Celular , Interações Hospedeiro-Patógeno , Plasmídeos/genética , Salmonella enterica/genética , Salmonella enteritidis/genética , Salmonella typhimurium/genética , Fatores de Virulência/genética , Animais , Apoptose , Citocalasina D/farmacologia , Replicação do DNA , Genes Bacterianos , Humanos , Camundongos , Viabilidade Microbiana , Necrose , Células RAW 264.7 , Salmonelose Animal/microbiologia , Salmonella enterica/patogenicidade , Salmonella enteritidis/patogenicidade , Salmonella typhimurium/patogenicidade , Sorogrupo , Suínos , Células THP-1 , Virulência
15.
Small ; 14(44): e1802086, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30191658

RESUMO

The ability to control the subcellular localization of nanoparticles within living plants offers unique advantages for targeted biomolecule delivery and enables important applications in plant bioengineering. However, the mechanism of nanoparticle transport past plant biological membranes is poorly understood. Here, a mechanistic study of nanoparticle cellular uptake into plant protoplasts is presented. An experimentally validated mathematical model of lipid exchange envelope penetration mechanism for protoplasts, which predicts that the subcellular distribution of nanoparticles in plant cells is dictated by the particle size and the magnitude of the zeta potential, is advanced. The mechanism is completely generic, describing nanoparticles ranging from quantum dots, gold and silica nanoparticles, nanoceria, and single-walled carbon nanotubes (SWNTs). In addition, the use of imaging flow cytometry to investigate the influence of protoplasts' morphological characteristics on nanoparticle uptake efficiency is demonstrated. Using DNA-wrapped SWNTs as model nanoparticles, it is found that glycerolipids, the predominant lipids in chloroplast membranes, exhibit stronger lipid-nanoparticle interaction than phospholipids, the major constituent in protoplast membrane. This work can guide the rational design of nanoparticles for targeted delivery into specific compartments within plant cells without the use of chemical or mechanical aid, potentially enabling various plant engineering applications.


Assuntos
Nanoestruturas/química , Protoplastos/metabolismo , Citometria de Fluxo , Nanotubos de Carbono/química
16.
Nat Mater ; 16(2): 264-272, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27798623

RESUMO

Plant nanobionics aims to embed non-native functions to plants by interfacing them with specifically designed nanoparticles. Here, we demonstrate that living spinach plants (Spinacia oleracea) can be engineered to serve as self-powered pre-concentrators and autosamplers of analytes in ambient groundwater and as infrared communication platforms that can send information to a smartphone. The plants employ a pair of near-infrared fluorescent nanosensors-single-walled carbon nanotubes (SWCNTs) conjugated to the peptide Bombolitin II to recognize nitroaromatics via infrared fluorescent emission, and polyvinyl-alcohol functionalized SWCNTs that act as an invariant reference signal-embedded within the plant leaf mesophyll. As contaminant nitroaromatics are transported up the roots and stem into leaf tissues, they accumulate in the mesophyll, resulting in relative changes in emission intensity. The real-time monitoring of embedded SWCNT sensors also allows residence times in the roots, stems and leaves to be estimated, calculated to be 8.3 min (combined residence times of root and stem) and 1.9 min mm-1 leaf, respectively. These results demonstrate the ability of living, wild-type plants to function as chemical monitors of groundwater and communication devices to external electronics at standoff distances.


Assuntos
Engenharia Genética/métodos , Hidrocarbonetos Aromáticos/metabolismo , Compostos de Nitrogênio/metabolismo , Peptídeos/metabolismo , Plantas Geneticamente Modificadas/fisiologia , Spinacia oleracea/fisiologia , Biônica/métodos , Substâncias Explosivas/análise , Hidrocarbonetos Aromáticos/análise , Raios Infravermelhos , Nanotubos de Carbono/química , Compostos de Nitrogênio/análise , Peptídeos/genética
17.
Nature ; 543(7646): 491, 2017 03 22.
Artigo em Inglês | MEDLINE | ID: mdl-28332517
18.
Arch Toxicol ; 92(2): 557-569, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29362863

RESUMO

The development of improved, innovative models for the detection of toxicity of drugs, chemicals, or chemicals in cosmetics is crucial to efficiently bring new products safely to market in a cost-effective and timely manner. In addition, improvement in models to detect toxicity may reduce the incidence of unexpected post-marketing toxicity and reduce or eliminate the need for animal testing. The safety of novel products of the pharmaceutical, chemical, or cosmetics industry must be assured; therefore, toxicological properties need to be assessed. Accepted methods for gathering the information required by law for approval of substances are often animal methods. To reduce, refine, and replace animal testing, innovative organotypic in vitro models have emerged. Such models appear at different levels of complexity ranging from simpler, self-organized three-dimensional (3D) cell cultures up to more advanced scaffold-based co-cultures consisting of multiple cell types. This review provides an overview of recent developments in the field of toxicity testing with in vitro models for three major organ types: heart, skin, and liver. This review also examines regulatory aspects of such models in Europe and the UK, and summarizes best practices to facilitate the acceptance and appropriate use of advanced in vitro models.


Assuntos
Técnicas de Cultura de Células , Coração/efeitos dos fármacos , Fígado/efeitos dos fármacos , Pele/efeitos dos fármacos , Testes de Toxicidade/métodos , Alternativas aos Testes com Animais/métodos , Animais , Qualidade de Produtos para o Consumidor , Humanos
19.
Nano Lett ; 17(12): 7951-7961, 2017 12 13.
Artigo em Inglês | MEDLINE | ID: mdl-29148804

RESUMO

The engineering of living plants for visible light emission and sustainable illumination is compelling because plants possess independent energy generation and storage mechanisms and autonomous self-repair. Herein, we demonstrate a plant nanobionic approach that enables exceptional luminosity and lifetime utilizing four chemically interacting nanoparticles, including firefly luciferase conjugated silica (SNP-Luc), d-luciferin releasing poly(lactic-co-glycolic acid) (PLGA-LH2), coenzyme A functionalized chitosan (CS-CoA) and semiconductor nanocrystal phosphors for longer wavelength modulation. An in vitro kinetic model incorporating the release rates of the nanoparticles is developed to maximize the chemiluminescent lifetimes to exceed 21.5 h. In watercress (Nasturtium officinale) and other species, the nanoparticles circumvent limitations such as luciferin toxicity above 400 µM and colocalization of enzymatic reactions near high adenosine triphosphate (ATP) production. Pressurized bath infusion of nanoparticles (PBIN) is introduced to deliver a mixture of nanoparticles to the entire living plant, well described using a nanofluidic mathematical model. We rationally design nanoparticle size and charge to control localization within distinct tissues compartments with 10 nm nanoparticles localizing within the leaf mesophyll and stomata guard cells, and those larger than 100 nm segregated in the leaf mesophyll. The results are mature watercress plants that emit greater than 1.44 × 1012 photons/sec or 50% of 1 µW commercial luminescent diodes and modulate "off" and "on" states by chemical addition of dehydroluciferin and coenzyme A, respectively. We show that CdSe nanocrystals can shift the chemiluminescent emission to 760 nm enabling near-infrared (nIR) signaling. These results advance the viability of nanobionic plants as self-powered photonics, direct and indirect light sources.


Assuntos
Brassicaceae/metabolismo , Substâncias Luminescentes/química , Nanopartículas/química , Nasturtium/metabolismo , Spinacia oleracea/metabolismo , Brassicaceae/química , Compostos de Cádmio/química , Compostos de Cádmio/metabolismo , Quitosana/análogos & derivados , Quitosana/química , Quitosana/metabolismo , Coenzima A/química , Coenzima A/metabolismo , Luciferina de Vaga-Lumes/química , Luciferina de Vaga-Lumes/metabolismo , Luz , Luciferases/química , Luciferases/metabolismo , Luminescência , Substâncias Luminescentes/metabolismo , Nasturtium/química , Folhas de Planta/química , Folhas de Planta/metabolismo , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/química , Radiação , Compostos de Selênio/química , Compostos de Selênio/metabolismo , Spinacia oleracea/química
20.
EMBO Rep ; 21(10): e51395, 2020 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-32924265
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