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2.
Children (Basel) ; 11(2)2024 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-38397312

RESUMO

Diagnostic reference levels (DRLs) are a pivotal strategy to be implemented since pediatric interventional cardiology procedures are increasing. This work aimed to propose an initial set of Brazilian DRLs for pediatric interventional diagnostic and therapeutic (D&T) procedures. A retrospective study was carried out in four Brazilian states, distributed across the three regions of the country. Data were collected from pediatric patients undergoing cardiac interventional procedures (CIPs), including their age and anthropometric characteristics, and at least four parameters (number of images, exposure time, air kerma-area product-PKA, and cumulative air kerma). Data from 279 patients undergoing CIPs were gathered (147 diagnostic and 132 therapeutic procedures). There were no significant differences in exposure time and the number of images between the D&T procedures. A wide range of PKA was observed when the therapeutic procedures were compared to diagnostics for all age groups. There were significant differences between the D&T procedures, whether grouping data by patient weight or age. In terms of cumulative air kerma, it was noted that no value exceeded the level to trigger a monitoring process for patients. This study shows that it is possible to adopt them as the first proposal to establish national DRLs considering pediatric patient groups.

3.
PLoS One ; 19(2): e0290815, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38300909

RESUMO

Local adaptation of populations results from an interplay between their environment and genetics. If functional trait variation influences plant performance, populations can adapt to their local environment. However, populations may also respond plastically to environmental challenges, altering phenotype without shifting allele frequencies. The level of local adaptation in crop landraces and their capacity for plasticity in response to environmental change may predict their continued utility to farmers facing climate change. Yet we understand little about how physiological traits potentially underlying local adaptation of cultivars influence fitness. Farmers in Mexico-the crop center of origin for maize-manage and rely upon a high diversity of landraces. We studied maize grown in Chiapas, Mexico, where strong elevational gradients cover a relatively small geographic area. We reciprocally transplanted 12 populations sourced from three elevational zones (600, 1550 and 2150 m) back into those elevations for two years using a modified split-split plot design to model effects of environment, genetics, and their interaction. We studied physiological and growth traits, including photosynthetic rate, stomatal conductance, stomatal density, relative growth rate (RGR), and seed production. Maize fitness showed indications of local adaptation with highland and midland types performing poorly at warmer lowland locations, though patterns depended on the year. Several physiological traits, including stomatal conductance, were affected by G x E interactions, some of which indicated non-adaptive plastic responses with potential fitness implications. We discerned a significant positive relationship between fitness and relative growth rate. Growth rates in highland landraces were outperformed by midland and lowland landraces grown in high temperature, lowland garden. Lowland landrace stomatal conductance was diminished compared to that of highland landraces in the cooler highland garden. Thus, both adaptive and non-adaptive physiological responses of maize landraces in southern Mexico may have implications for fitness, as well as responses to climate change.


Assuntos
Meio Ambiente , Zea mays , Zea mays/genética , México , Fenótipo , Fotossíntese , Adaptação Fisiológica/genética
4.
Rev Argent Microbiol ; 56(2): 115-124, 2024.
Artigo em Espanhol | MEDLINE | ID: mdl-38155042

RESUMO

Waterborne diseases can have different origins, micro-organisms such as bacteria and parasites being the most important ones. In this study, two recreational aquatic environments were studied in the province of Salta, Argentina. Water samples collected from three different locations, two from a creek and one from the outlet of a thermal complex, were monitored at four time points. Physicochemical and microbiological characterization of each point was conducted, as well as a search for parasites and amebae. Parasites were identified through optical microscopy observations and free-living amebae (FLA) were isolated by spiking in Petri dishes followed by subsequent molecular identification. Water samples from the outlet of the thermal complex showed different physicochemical characteristics from those of the creek. Bacterial indicators of contamination were detected at all points; however, the creek water had a significantly higher concentration of Pseudomonas sp. Sporadically, creek samples exhibited Ascaris spp. eggs, Giardia sp. cysts, and ancylostomid eggs. The presence of FLA was observed in all samples, 15 of which were isolated and identified as Acanthamoeba sp., mostly belonging to the T4 genotype. Parasite surveillance in recreational aquatic environments is an important complement to traditional microbial indicators for assessing water quality. The identified parasites represent a potential health risk for people using these environments.


Assuntos
Recreação , Argentina , Animais , Humanos , Microbiologia da Água , Água Doce/parasitologia , Água Doce/microbiologia , Parasitos/isolamento & purificação , Parasitos/classificação
5.
Cureus ; 15(11): e48896, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38024051

RESUMO

Aim In response to the coronavirus 2019 disease (COVID-19) pandemic, governments worldwide implemented measures to prevent infection, resulting in restricted school activities, restricted children's freedom of movement, and increased risk of violence and injuries at home, including traumatic brain injury (TBI), among children. In Brazil, the consequences of the COVID-19 pandemic on the causes, severity, and mortality of pediatric TBI have not yet been investigated. Thus, our study aimed to determine whether the COVID-19 pandemic has affected the epidemiology of pediatric TBI among Brazilian children. Materials and methods We investigated the patients with TBI aged <18 years who visited a tertiary trauma center in Brazil in 2019 and 2020. TBI-related variables, such as classification, mechanism, clinical manifestations, need for intervention, morbidity, and mortality, were recorded. Furthermore, we used a nationwide databank to collect information on mortality from external causes of trauma and violence in the pediatric population in 2019 and 2020. The Mann-Whitney test was used to compare quantitative variables related to the mechanisms and severity of TBI in both periods in order to determine the impact of the COVID-19 pandemic. Results Of the patients with traumatic brain injury, 1371 visited the trauma center in 2019 and 1052 in 2020. No difference was noted in the incidence rate of abusive head trauma between these periods (p=0.142) or in mortality from violence in Brazil. Recreational causes of pediatric TBI increased during the first year of the COVID-19 pandemic in Brazil and falls from bicycles significantly increased during the pandemic (p<0.001). Conclusion A global reduction in pediatric admissions to emergency rooms as well as no impact on mortality and severity of pediatric TBI were observed during the COVID-19 pandemic in Brazil. Additionally, a public education program regarding child safety during recreational activities, particularly how to avoid falls from bicycles was recommended.

6.
J Environ Manage ; 342: 118034, 2023 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-37187070

RESUMO

Intense urbanisation in many coastal areas has led to intensification of groundwater consumption, while reducing permeable areas and increasing the frequency and magnitude of flooding. Among the potential strategies to compensate for these adverse effects, which are expected to become worse as a result of climate change, rooftop rainwater harvesting (RWH) in combination with managed aquifer recharge (MAR), may be indicated. This work investigated the performance of different configurations of such a system, tested as a twofold sustainable stormwater and domestic water management tool in a tropical metropole (João Pessoa, Brazil). This area located over a sedimentary aquifer system illustrates the water security challenges of densely urbanised areas in southern cities. To that end, several configurations of rooftop catchments and storage volumes were evaluated, by simulating a MAR-RWH system connected to the regional unconfined aquifer (Barreiras Formation) through a 6″ diameter injection well. Rainfall-runoff-recharge processes and water balances were simulated using monitored high-temporal resolution rainfall data. The results showed that catchments ranging from 180 to 810 m2, connected to tanks from 0.5 to 30.0 m³, are the optimal solutions in terms of efficient rainwater retention and peak flow reduction. These solutions provided mean annual estimates of aquifer recharge between 57 and 255 m³/yr from 2004 to 2019. The results of this study highlight the opportunity for MAR schemes to reconcile stormwater management and water supply goals.


Assuntos
Água Subterrânea , Água , Cidades , Inundações , Brasil
7.
Rev. colomb. cardiol ; 29(6): 680-683, dic. 2022. tab, graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1423799

RESUMO

Abstract: Coronary artery disease continues to be the leading cause of death in modern society; the most frequent cause is atherosclerosis. There are other causes such as coronary embolism and coronary dissection, among others. This article presents the case of a young patient with acute myocardial infarction in whom a coronary embolism was documented as the cause of infarction.


Resumen: La enfermedad arterial coronaria continúa siendo una causa de mortalidad en nuestro medio; la causa más frecuente es la aterosclerosis. Existen otras causas como embolia coronaria, disección coronaria. En este artículo se describe el caso de un paciente joven, quien presentó un infarto agudo de miocardio y se documentó un embolia conoraria como causa.

8.
Rev Bras Med Trab ; 20(1): 122-131, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36118057

RESUMO

There is evidence that harm to the mental health of healthcare workers has occurred during the pandemic caused by COVID-19. The burnout syndrome is a form of exhaustion that occurs in occupational settings and is a condition caused by long-term stress in the workplace. The objectives of this systematic review of observational studies were to present data from research into the prevalence of burnout syndrome in healthcare workers during the COVID-19 pandemic and observe its prevalence among frontline workers. The search was conducted on the MEDLINE, LILACS, and Embase databases from 2019 to May of 2021 and returned 538 publications, which underwent a two-stage process of selection by independent peers, resulting in selection of a sample of 29 articles. Data were then extracted and synthesized for presentation in narrative form. Cross-sectional designs were more prevalent (n = 26) than longitudinal studies (n = 3). The sample included research from 19 different countries, with one Brazilian study. A wide range of different instruments were administered by study authors to assess burnout syndrome, the most common of which was the Maslach Burnout Inventory (n = 13). The prevalence of burnout syndrome in the studies varied from 76 to 14.7%. Data on the relationship between development of burnout syndrome and working on the frontline were controversial. The lack of standardization of burnout syndrome assessment was a source of considerable difficulty, compromising comparability of the results, and should therefore be targeted for improvement by researchers. We suggest that more investigations should be conducted into prevalence and the associated factors of risk and protection.

9.
Int J Exerc Sci ; 15(3): 733-746, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35991348

RESUMO

The purpose of this study was to investigate the effects of two different exercise training programs periodization on anthropometric and functional parameters in people living with HIV (PLHIV). This was a randomized clinical trial that involved participants (n = 31) living with HIV aged over 18 years and undergoing antiretroviral therapy which were randomized to periodized exercise training (PET; n = 13), non-periodized exercise training (NPET; n = 13), or control group (CON; n = 15). The PET and NPET groups performed 12 weeks of combined training while the CON group maintained the usual activities. Before and after 12 weeks of intervention were measured body composition and perimeters, muscle strength, Short Physical Performance Battery (SPPB) and Timed Up and Go (TUG) test time. Results: The PET and NPET groups increased fat-free mass (p < 0,001), right (p < 0,001) and left thigh perimeter (p < 0,001), muscle strength (p < 0,001), handgrip force (p < 0,001), and reduced the fat mass (p < 0,001), neck perimeter (p < 0,001), chair stand (p < 0,001), and time-up and go test time (p < 0,001) compared to CON. Furthermore, PET was significantly different to increase right thigh and muscle strength (p < 0,05) compared to NPET. Conclusion: Both exercise training periodization protocols were effective to improve body composition and functional outcomes; however, seems that PET presents better results compare to NPET in PLHIV.

10.
Int Endod J ; 55(10): 967-988, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35821587

RESUMO

BACKGROUND: Current treatment of immature necrotic permanent teeth with a periapical lesion is regenerative endodontics, which is based on tissue engineering under the triade of stem cells, scaffolds and bioactive molecules. OBJECTIVES: This Umbrella Review was aimed to evaluate the success of scaffold and regenerative materials used for the treatment of these teeth, in terms of apical closure, tooth length increase, widening of root canal walls, tissue vitality and periapical lesion repair. METHODS: An extensive literature research was carried out in the Medline, ISI Web of Science, and Scopus databases for relevant systematic reviews matching the keyword search strategy. Based on inclusion and exclusion criteria, reviewers independently rated the quality of each study to determine their level of evidence. Methodological quality assessment of each article was obtained using A Measurement Tool to Assess Systematic Reviews (AMSTAR)-2 tool, and risk of bias was assessed with the Risk of Bias in Systematic Reviews (ROBIS) tool. RESULTS: After removing duplicates, 155 articles were found; from which 133 were excluded for being non-relevant and 15 other due to exclusion criteria. One more was discarded after methodological quality evaluation, for a total of six articles remaining. The most common scaffold used was the blood clot, others used were poly lactic-co-glycolic acid and platelet-rich fibrin matrix. The most common regeneration material used was Mineral Trioxide Aggregate (MTA), followed by Biodentine. An increase in tooth length and widening of root canal walls were reported in all selected studies with different proportions, as well as periapical lesion repair. ROBIS analysis showed that only one article had low bias, two were classified as unclear bias, while the remaining three had high risk of bias. DISCUSSION: An exhaustive literature search was carried out applying language filters, high-quality indexed journals, year of publication, which ensures the best quality articles were included. Blood clot was the most used scaffold as is the most easy to place inside the canal and does not require to extract blood from the patient. The use of MTA and Biodentine as sealing materials has been associated with thickening of canal walls, apical closure and reduced signs and symptoms of apical periodontitis. However, most of the included reviews assessed were case reports and only in a few of them were clinical trials included. There is also a lack of risk of bias analysis in most reviews. CONCLUSION: The blood clot is the most common scaffold used for inducing regeneration during the treatment of immature necrotic teeth. Tooth length increase and widening of root canal walls are the most common criteria used in the studies as success indicators. MTA and Biodentine did not show differences in the results analysed. Quality assessment and bias risk evaluation showed that it is necessary to design better studies with rigorous methodology to recommend a trustable and predictable protocol for the treatment of immature necrotic permanent teeth with periapical lesions. REGISTRATION: International Prospective Register of Systematic Reviews (PROSPERO) CRD42021248404.


Assuntos
Periodontite Periapical , Trombose , Humanos , Necrose da Polpa Dentária/terapia , Periodontite Periapical/terapia , Tratamento do Canal Radicular/métodos , Revisões Sistemáticas como Assunto
11.
Parasitol Res ; 121(5): 1329-1343, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35169884

RESUMO

Echinococcus granulosus, the etiological agent of human cystic echinococcosis (formerly known as hydatid disease), represents a serious worldwide public health problem with limited treatment options. The essential role played by the neuromuscular system in parasite survival and the relevance of serotonin (5-HT) in parasite movement and development make the serotonergic system an attractive source of drug targets. In this study, we cloned and sequenced a cDNA coding for the serotonin transporter from E. granulosus (EgSERT). Bioinformatic analyses suggest that EgSERT has twelve transmembrane domains with highly conserved ligand and ionic binding sites but a less conserved allosteric site compared with the human orthologue (HsSERT). Modeling studies also suggest a good degree of conservation of the overall structure compared with HsSERT. Functional and pharmacological studies performed on the cloned EgSERT confirm that this protein is indeed a serotonin transporter. EgSERT is specific for 5-HT and does not transport other neurotransmitters. Typical monoamine transport inhibitors also displayed inhibitory activities towards EgSERT, but with lower affinity than for the human SERT (HsSERT), suggesting a high divergence of the cestode transporter compared with HsSERT. In situ hybridization studies performed in the larval protoscolex stage suggest that EgSERT is located in discrete regions that are compatible with the major ganglia of the serotonergic nervous system. The pharmacological properties, the amino acidic substitutions at important functional regions compared with the HsSERT, and the putative role of EgSERT in the nervous system suggest that it could be an important target for pharmacological intervention.


Assuntos
Cestoides , Equinococose , Echinococcus granulosus , Animais , Equinococose/parasitologia , Echinococcus granulosus/fisiologia , Humanos , Sistema Nervoso/metabolismo , Serotonina/metabolismo , Serotonina/farmacologia , Proteínas da Membrana Plasmática de Transporte de Serotonina/genética , Proteínas da Membrana Plasmática de Transporte de Serotonina/metabolismo
12.
Am J Hum Genet ; 109(2): 299-310, 2022 02 03.
Artigo em Inglês | MEDLINE | ID: mdl-35090584

RESUMO

Spontaneous clearance of acute hepatitis C virus (HCV) infection is associated with single nucleotide polymorphisms (SNPs) on the MHC class II. We fine-mapped the MHC region in European (n = 1,600; 594 HCV clearance/1,006 HCV persistence) and African (n = 1,869; 340 HCV clearance/1,529 HCV persistence) ancestry individuals and evaluated HCV peptide binding affinity of classical alleles. In both populations, HLA-DQß1Leu26 (p valueMeta = 1.24 × 10-14) located in pocket 4 was negatively associated with HCV spontaneous clearance and HLA-DQß1Pro55 (p valueMeta = 8.23 × 10-11) located in the peptide binding region was positively associated, independently of HLA-DQß1Leu26. These two amino acids are not in linkage disequilibrium (r2 < 0.1) and explain the SNPs and classical allele associations represented by rs2647011, rs9274711, HLA-DQB1∗03:01, and HLA-DRB1∗01:01. Additionally, HCV persistence classical alleles tagged by HLA-DQß1Leu26 had fewer HCV binding epitopes and lower predicted binding affinities compared to clearance alleles (geometric mean of combined IC50 nM of persistence versus clearance; 2,321 nM versus 761.7 nM, p value = 1.35 × 10-38). In summary, MHC class II fine-mapping revealed key amino acids in HLA-DQß1 explaining allelic and SNP associations with HCV outcomes. This mechanistic advance in understanding of natural recovery and immunogenetics of HCV might set the stage for much needed enhancement and design of vaccine to promote spontaneous clearance of HCV infection.


Assuntos
Cadeias beta de HLA-DQ/genética , Hepacivirus/patogenicidade , Hepatite C/genética , Interações Hospedeiro-Patógeno/genética , Polimorfismo de Nucleotídeo Único , Doença Aguda , Alelos , Substituição de Aminoácidos , População Negra , Feminino , Expressão Gênica , Estudo de Associação Genômica Ampla , Genótipo , Cadeias beta de HLA-DQ/imunologia , Hepacivirus/crescimento & desenvolvimento , Hepacivirus/imunologia , Hepatite C/etnologia , Hepatite C/imunologia , Hepatite C/virologia , Interações Hospedeiro-Patógeno/imunologia , Humanos , Leucina/imunologia , Leucina/metabolismo , Masculino , Prolina/imunologia , Prolina/metabolismo , Isoformas de Proteínas/genética , Isoformas de Proteínas/imunologia , Remissão Espontânea , População Branca
13.
Sci Total Environ ; 805: 150136, 2022 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-34818799

RESUMO

Arid zones contain a diverse set of microbes capable of survival under dry conditions, some of which can form relationships with plants under drought stress conditions to improve plant health. We studied squash (Cucurbita pepo L.) root microbiome under historically arid and humid sites, both in situ and performing a common garden experiment. Plants were grown in soils from sites with different drought levels, using in situ collected soils as the microbial source. We described and analyzed bacterial diversity by 16S rRNA gene sequencing (N = 48) from the soil, rhizosphere, and endosphere. Proteobacteria were the most abundant phylum present in humid and arid samples, while Actinobacteriota abundance was higher in arid ones. The ß-diversity analyses showed split microbiomes between arid and humid microbiomes, and aridity and soil pH levels could explain it. These differences between humid and arid microbiomes were maintained in the common garden experiment, showing that it is possible to transplant in situ diversity to the greenhouse. We detected a total of 1009 bacterial genera; 199 exclusively associated with roots under arid conditions. By 16S and shotgun metagenomics, we identified dry-associated taxa such as Cellvibrio, Ensifer adhaerens, and Streptomyces flavovariabilis. With shotgun metagenomic sequencing of rhizospheres (N = 6), we identified 2969 protein families in the squash core metagenome and found an increased number of exclusively protein families from arid (924) than humid samples (158). We found arid conditions enriched genes involved in protein degradation and folding, oxidative stress, compatible solute synthesis, and ion pumps associated with osmotic regulation. Plant phenotyping allowed us to correlate bacterial communities with plant growth. Our study revealed that it is possible to evaluate microbiome diversity ex-situ and identify critical species and genes involved in plant-microbe interactions in historically arid locations.


Assuntos
Cucurbita , Microbiota , Rhizobiaceae , Humanos , Metagenoma , Metagenômica , Raízes de Plantas , RNA Ribossômico 16S , Rizosfera , Microbiologia do Solo , Streptomyces
14.
Pest Manag Sci ; 78(2): 749-757, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34693637

RESUMO

BACKGROUND: Amaranthus palmeri S. Watson, a problematic weed infesting summer crops in Argentina, has developed multiple herbicide resistance. Resistance to acetolactate synthase (ALS)-inhibiting herbicides is particularly common, with high-level resistance mostly caused by different mutations in the ALS enzyme. Six versions of the enzyme were identified from a resistant A. palmeri population, carrying substitutions D376E, A205V, A122S, A282D, W574L and S653N. This work aims to provide a comparative analysis of these mutants and the wild-type (WT) enzyme to fully understand the herbicide resistance. Thus, all the versions of the ALS gene from A. palmeri were heterologously expressed and purified to evaluate their kinetics and inhibitory response against imazethapyr, diclosulam, chlorimuron-ethyl, flucarbazone-sodium and bispyribac-sodium. RESULTS: A decrease in catalytic efficiency was detected in the A205V, A122S-A282D, W574L and S653N ApALS enzymes, whereas only A205V and W574L substitutions also produced a decrease in the substrate affinity. In vitro ALS inhibition assays confirmed cross-resistance to almost all the herbicides tested, with the exception of A282D ApALS, which was as susceptible as WT ApALS. Moreover, the results confirmed that the novel substitution A122S provides cross-resistance to at least one herbicide within each of the five families of ALS inhibitors, and this property could be explained by a lower number of hydrophobic interactions between the herbicides and the mutant enzyme. CONCLUSION: This is the first report to compare various mutations in vitro from A. palmeri ALS. Our data contribute to understanding the impacts of herbicide resistance in this species. © 2021 Society of Chemical Industry.


Assuntos
Acetolactato Sintase , Amaranthus , Herbicidas , Acetolactato Sintase/genética , Amaranthus/genética , Resistência a Herbicidas/genética , Herbicidas/farmacologia , Mutação de Sentido Incorreto , Proteínas de Plantas/genética
15.
New Phytol ; 233(1): 84-118, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34515358

RESUMO

Crop diversity underpins the productivity, resilience and adaptive capacity of agriculture. Loss of this diversity, termed crop genetic erosion, is therefore concerning. While alarms regarding evident declines in crop diversity have been raised for over a century, the magnitude, trajectory, drivers and significance of these losses remain insufficiently understood. We outline the various definitions, measurements, scales and sources of information on crop genetic erosion. We then provide a synthesis of evidence regarding changes in the diversity of traditional crop landraces on farms, modern crop cultivars in agriculture, crop wild relatives in their natural habitats and crop genetic resources held in conservation repositories. This evidence indicates that marked losses, but also maintenance and increases in diversity, have occurred in all these contexts, the extent depending on species, taxonomic and geographic scale, and region, as well as analytical approach. We discuss steps needed to further advance knowledge around the agricultural and societal significance, as well as conservation implications, of crop genetic erosion. Finally, we propose actions to mitigate, stem and reverse further losses of crop diversity.


Assuntos
Conservação dos Recursos Naturais , Produtos Agrícolas , Agricultura , Produtos Agrícolas/genética , Ecossistema
16.
Sensors (Basel) ; 21(23)2021 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-34884014

RESUMO

We demonstrate a concept for a large enhancement of the directivity and gain of readily available cm- and mm-wave antennas, i.e., without altering any property of the antenna design. Our concept exploits the high reflectivity of a Bragg reflector composed of three bilayers made of transparent materials. The cavity has a triangular aperture in order to resemble the idea of a horn-like, highly directive antenna. Importantly, we report gain enhancements of more than 400% in relation to the gain of the antenna without the Bragg structure, accompanied by a highly directive radiation pattern. The proposed structure is cost-effective and easy to fabricate with 3D-printing. Our results are presented for frequencies within the conventional WiFi frequencies, based on IEEE 802.11 standards, thus, enabling easily implementation by non-experts and needing only to be placed around the antenna to improve the directivity and gain of the signal.

17.
Phys Chem Chem Phys ; 23(48): 27348-27354, 2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34854859

RESUMO

Bilirubin oxidases (BOD) are metalloenzymes that catalyze the conversion of O2 and bilirubin to biliverdin and water in the metabolism of chlorophyll and porphyrin. In this work we have used the CpHMD method to analyze the effects of the different oxidation states on the BOD trinuclear cluster (TNC). Our results demonstrate that there is a link between the different oxidation states of copper ions and the protonation capacity of nearby titratable residues. Each configuration affects pKa differently, creating proton gradients within the enzyme that act in an extremely orderly manner. This order is closely linked to the catalytic mechanism and leads us to the conclusion of the entry of the O2 molecule and its reduction in water molecules is associated with the probability of the release of protons from nearby acid groups. With this information, we deduce that under the initial reaction conditions the acidic side chains of nearby residues can be protonated; this allows the enzyme to reduce the activation energy of the reaction by coupling the proton transfer to oxidation state changes in the metallic center.


Assuntos
Simulação de Dinâmica Molecular , Oxirredutases atuantes sobre Doadores de Grupo CH-CH/química , Prótons , Concentração de Íons de Hidrogênio , Oxirredução , Oxirredutases atuantes sobre Doadores de Grupo CH-CH/metabolismo
18.
Front Plant Sci ; 12: 768393, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34804102

RESUMO

The available methods for plant transformation and expansion beyond its limits remain especially critical for crop improvement. For grass species, this is even more critical, mainly due to drawbacks in in vitro regeneration. Despite the existence of many protocols in grasses to achieve genetic transformation through Agrobacterium or biolistic gene delivery, their efficiencies are genotype-dependent and still very low due to the recalcitrance of these species to in vitro regeneration. Many plant transformation facilities for cereals and other important crops may be found around the world in universities and enterprises, but this is not the case for apomictic species, many of which are C4 grasses. Moreover, apomixis (asexual reproduction by seeds) represents an additional constraint for breeding. However, the transformation of an apomictic clone is an attractive strategy, as the transgene is immediately fixed in a highly adapted genetic background, capable of large-scale clonal propagation. With the exception of some species like Brachiaria brizantha which is planted in approximately 100 M ha in Brazil, apomixis is almost non-present in economically important crops. However, as it is sometimes present in their wild relatives, the main goal is to transfer this trait to crops to fix heterosis. Until now this has been a difficult task, mainly because many aspects of apomixis are unknown. Over the last few years, many candidate genes have been identified and attempts have been made to characterize them functionally in Arabidopsis and rice. However, functional analysis in true apomictic species lags far behind, mainly due to the complexity of its genomes, of the trait itself, and the lack of efficient genetic transformation protocols. In this study, we review the current status of the in vitro culture and genetic transformation methods focusing on apomictic grasses, and the prospects for the application of new tools assayed in other related species, with two aims: to pave the way for discovering the molecular pathways involved in apomixis and to develop new capacities for breeding purposes because many of these grasses are important forage or biofuel resources.

19.
PLoS One ; 16(11): e0259104, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34762657

RESUMO

Cestodes are platyhelminth parasites with a wide range of hosts that cause neglected diseases. Neurotransmitter signaling is of critical importance for these parasites which lack circulatory, respiratory and digestive systems. For example, serotonin (5-HT) and serotonergic G-protein coupled receptors (5-HT GPCRs) play major roles in cestode motility, development and reproduction. In previous work, we deorphanized a group of 5-HT7 type GPCRs from cestodes. However, little is known about another type of 5-HT GPCR, the 5-HT1 clade, which has been studied in several invertebrate phyla but not in platyhelminthes. Three putative 5-HT GPCRs from Echinococcus canadensis, Mesocestoides vogae (syn. M. corti) and Hymenolepis microstoma were cloned, sequenced and bioinformatically analyzed. Evidence grouped these new sequences within the 5-HT1 clade of GPCRs but differences in highly conserved GPCR motifs were observed. Transcriptomic analysis, heterologous expression and immunolocalization studies were performed to characterize the E. canadensis receptor, called Eca-5-HT1a. Functional heterologous expression studies showed that Eca-5-HT1a is highly specific for serotonin. 5-Methoxytryptamine and α-methylserotonin, both known 5-HT GPCR agonists, give stimulatory responses whereas methysergide, a known 5-HT GPCR ligand, give an antagonist response in Eca-5-HT1a. Mutants obtained by the substitution of key predicted residues resulted in severe impairment of receptor activity, confirming that indeed, these residues have important roles in receptor function. Immunolocalization studies on the protoscolex stage from E. canadensis, showed that Eca-5-HT1a is localized in branched fibers which correspond to the nervous system of the parasite. The patterns of immunoreactive fibers for Eca-5-HT1a and for serotonin were intimately intertwined but not identical, suggesting that they are two separate groups of fibers. These data provide the first functional, pharmacological and localization report of a serotonergic receptor that putatively belongs to the 5-HT1 type of GPCRs in cestodes. The serotonergic GPCR characterized here may represent a new target for antiparasitic intervention.


Assuntos
Cestoides/metabolismo , Proteínas de Helminto/metabolismo , Sistema Nervoso/metabolismo , Receptores 5-HT1 de Serotonina/metabolismo , Sequência de Aminoácidos , Animais , Echinococcus/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Proteínas de Helminto/química , Proteínas de Helminto/genética , Humanos , Hymenolepis/metabolismo , Receptores 5-HT1 de Serotonina/química , Receptores 5-HT1 de Serotonina/genética , Alinhamento de Sequência , Antagonistas da Serotonina/farmacologia , Agonistas do Receptor de Serotonina/farmacologia
20.
Genes (Basel) ; 12(10)2021 10 09.
Artigo em Inglês | MEDLINE | ID: mdl-34680981

RESUMO

The American tropics are hotspots of wild and domesticated plant biodiversity, which is still underutilized by breeding programs despite being conserved at regional gene banks. The improvement of those programs depends on long-term public funds and the maintenance of specialized staff. Unfortunately, financial ups and downs complicate staff connectivity and their research impact. Between 2000 and 2010, Agrosavia (Corporación Colombiana de Investigación Agropecuaria) dramatically decreased its public financial support. In 2017, we surveyed all 52 researchers from Agrosavia involved in plant breeding and plant genetic resource programs to examine the effect of decimating funds in the last ten years. We hypothesized that the staff dedicated to plant breeding still suffer a strong fragmentation and low connectivity. As we expected, the social network among researchers is weak. The top ten central leaders are predominantly males with an M.Sc. degree but have significant experience in the area. The staff has experience in 31 tropical crops, and 17 are on the list of underutilized species. Moreover, although 26 of these crops are in the national germplasm bank, this has not been the primary source for their breeding programs. We proposed five principles to improve connectivity among teams and research impact: (1) The promotion of internal discussion about gender gaps and generation shifts to design indicators to monitor and decrease this disparity over time. (2) The construction of long-term initiatives and synergies with the Colombian government to support the local production of food security crops independent of market trends. (3) Better collaboration between the National Plant Germplasm Bank and plant breeding researchers. (4) A concerted priority list of species (especially those neglected or underutilized) and external institutions to better focus the collaborative efforts in research using public funds. (5) Better spaces for the design of projects among researchers and training programs in new technologies. These principles could also apply in other tropical countries with public plant breeding research programs facing similar challenges.


Assuntos
Genes de Plantas , Melhoramento Vegetal , Plantas/genética , Clima Tropical , Adulto , Biodiversidade , Colômbia , Produtos Agrícolas/genética , Feminino , Humanos , Masculino , Pesquisadores
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