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Argentina is among the most important lemon fruit producers in the world. Penicillium digitatum is the primary lemon fungal phytopathogen, causing green mold during the postharvest. Several alternatives to the use of synthetic fungicides have been developed, being the use of biocontrol yeasts one of the most promising. Although many of the reports are based on the use of a single yeast species, it has been shown that the combination of agents with different mechanisms of action can increase control efficiency through synergistic effects. The combined use of native yeasts with different mechanisms of action had not been studied as a biological control strategy in lemons. In this work, the mechanisms of action of native yeasts (Clavispora lusitaniae AgL21, Clavispora lusitaniae AgL2 and Clavispora lusitaniae AcL2) with biocontrol activity against P. digitatum were evaluated. Isolate AgL21 was selected for its ability to form biofilm, colonize lemon wounds, and inhibit fungal spore germination. The compatibility of C. lusitaniae AgL21 with two killer yeasts of the species Kazachstania exigua (AcL4 and AcL8) was evaluated. In vivo assays were then carried out with the yeasts applied individually or mixed in equal cell concentrations. AgL21 alone was able to control green mold with 87.5% efficiency, while individual killer yeasts were significantly less efficient (43.3% and 38.3%, respectively). Inhibitory effects were increased when C. lusitaniae AgL21 and K. exigua strains were jointly applied. The most efficient treatment was the combination of AgL21 and AcL4, reaching 100% efficiency in wound protection. The combination of AgL21 with AcL8 was as well promising, with an efficiency of 97.5%. The combined application of native yeasts showed a synergistic effect considering that the multiple mechanisms of action involved could hinder the development of green mold in lemon more efficiently than using single yeasts. Therefore, this work demonstrates that the integration of native yeasts with diverse modes of action can provide new insights to formulate effective microbial consortia. This could lead to the development of tailor-made biofungicides, allowing control of postharvest fungal diseases in lemons while remaining competitive with traditionally used synthetic chemicals.
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Citrus , Fungicidas Industriais , Penicillium , Saccharomycetales , Leveduras , Citrus/microbiologia , Fungicidas Industriais/farmacologia , Esporos Fúngicos , Frutas/microbiologia , Doenças das Plantas/microbiologiaRESUMO
Biological therapies have transformed high-burden treatments. As the patent and exclusivity period for biological medicines draws to a close, there is a possibility for the development and authorization of biosimilars. These products boast comparable levels of safety, quality, and effectiveness to their precursor reference products. Biosimilars, although similar to reference products, are not identical copies and should not be considered generic substitutes for the original. Their development and evaluation involve a rigorous step-by-step process that includes analytical, functional, and nonclinical evaluations and clinical trials. Clinical studies conducted for biosimilars aim to establish similar efficacy, safety, and immunogenicity, rather than demonstrating a clinical benefit, as with the reference product. However, although the current knowledge regarding biosimilars has significantly increased, several controversies and misconceptions still exist regarding their immunogenicity, extrapolation, interchangeability, substitution, and nomenclature. The development of biosimilars stimulates market competition, contributes toward healthcare sustainability, and allows for greater patient access. However, maximizing the benefits of biosimilars requires cooperation between regulators and developers to ensure that patients can benefit quickly from access to these new therapeutic alternatives while maintaining high standards of quality, safety, and efficacy. Recognizing the inherent complexities of comprehending biosimilars fully, it is essential to focus on realistic approaches, such as fostering open communication between healthcare providers and patients, encouraging informed decision-making, and minimizing risks. This review addresses the regulatory and manufacturing requirements for biosimilars and provides clinicians with relevant insights for informed prescribing.
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Introducción. La evaluación de la movilidad de las cuerdas vocales en cirugía de tiroides y paratiroides hace parte de la adecuada valoración integral. Aunque la laringoscopia directa es prueba de referencia, su uso real no es rutinario por lo que se propone la ecografía translaríngea como alternativa de evaluación. Métodos. Estudio prospectivo de evaluación de una prueba diagnóstica de la movilidad de las cuerdas vocales pre y posoperatoria, comparando la ecografía translaríngea con la video laringoscopia, en pacientes con cirugía de tiroides y paratiroides, de febrero 1° a noviembre 30 de 2022. Se describieron las variables usando frecuencias absolutas y relativas. En el análisis univariado se calcularon Chi cuadrado y T de Student y en el bivariado, regresión logística binaria. La agudeza diagnóstica se determinó con sensibilidad, especificidad y valores predictivos; se consideró la significancia estadística con p < 0,05. Resultados. Se incluyeron 267 pacientes, 219 mujeres y 48 hombres; 196 pacientes (73,4%) tenían malignidad. Se encontró en el preoperatorio, sensibilidad 100 %, especificidad 99,6 %, VPP 83,3 %, VPN 100 %, odds de probabilidad positiva 83 % y Odds de probabilidad negativa 0,004 %. En el posoperatorio, sensibilidad 82,8 %, especificidad 99,2 %, VPP 92,3 % VPN 97,9 %, odds de probabilidad positiva 92 % y odds de probabilidad negativa 0,2 %. Conclusiones. La ecografía translaríngea en nuestro medio tiene alta agudeza diagnóstica. Podría ser usada en el abordaje inicial de la evaluación de la movilidad de las cuerdas vocales y reemplazar la laringoscopia directa, dejando ésta para cuando la visualización ecográfica no sea adecuada, o en casos de afectación o sospecha de invasión, para su confirmación.
Introduction. The evaluation of the mobility of the vocal cords in thyroid and parathyroid surgery is part of the adequate comprehensive assessment. Altough, direct laryngoscopy is the gold standard, its real use is not routine, so translaryngeal ultrasound approach is proposed as an alternative. Methods. A prospective diagnostic test study was carried out to evaluate the translaryngeal ultrasound compared with video laryngoscopy in visualizing vocal mobility in patients with thyroid and parathyroid surgery from February 1 to November 30, 2022. Patients were described using absolute and relative frequencies. Univariate statistical analysis with Chi-square and Student's t tests. T. Bivariate analysis using binary logistic regression. Diagnostic acuity was calculated with sensitivity, specificity, PPV, NPV. Statistical significance with p< 0.05, 95% confidence interval. Results. 267 patients undergoing thyroid or parathyroid surgery were included, 219 women and 48 men. Malignant: thyroid neoplasm 196 patients (73.4%). The findings were for the preoperative period, 100% sensitivity, 99.6% specificity, PPV 83.33%, NPV 100%, 83% positive probability odds, and 0.004% negative probability odds. For the postoperative period, 82.8% sensitivity, 99.2% specificity, 92.3% PPV, 97.9% NPV, 92% positive probability odds, and 0.2% negative probability odds were found.Conclusions. Translaryngeal ultrasound in our series has high diagnostic acuity. It could be used as the initial approach to evaluate vocal mobility and might replace direct laryngoscopy, leaving it when its visualization is not adequate or in cases of involvement or suspected invasion for confirmation.
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Humanos , Doenças da Glândula Tireoide , Prega Vocal , Diagnóstico por Imagem , Glândula Tireoide , Ultrassonografia , LaringeRESUMO
Previous studies have noted that persons living with human immunodeficiency virus (HIV) experience persistent lung dysfunction after an episode of community-acquired pneumonia (CAP), although the underlying mechanisms remain unclear. We hypothesized that inflammation during pneumonia triggers increased tissue damage and accelerated pulmonary fibrosis, resulting in a gradual loss of lung function. We carried out a prospective cohort study of people diagnosed with CAP and/or HIV between 2016 and 2018 in three clinical institutions in Medellín, Colombia. Clinical data, blood samples, and pulmonary function tests (PFTs) were collected at baseline. Forty-one patients were included, divided into two groups: HIV and CAP (n = 17) and HIV alone (n = 24). We compared the concentrations of 17 molecules and PFT values between the groups. Patients with HIV and pneumonia presented elevated levels of cytokines and chemokines (IL-6, IL-8, IL-18, IL-1RA, IL-10, IP-10, MCP-1, and MIP-1ß) compared to those with only HIV. A marked pulmonary dysfunction was evidenced by significant reductions in FEF25, FEF25-75, and FEV1. The correlation between these immune mediators and lung function parameters supports the connection between pneumonia-associated inflammation and end organ lung dysfunction. A low CD4 cell count (<200 cells/µL) predicted inflammation and lung dysfunction. These results underscore the need for targeted clinical approaches to mitigate the adverse impacts of CAP on lung function in this population.
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Introducción: La obesidad es una enfermedad epidémica multifactorial en constante aumento en los últimos años. Asocia el desarrollo de múltiples patologías con aumento de la morbimortalidad, entre ellas el síndrome de apneas e hipopneas obstructivas del sueño (SAHOS). Objetivo: Estudiar la prevalencia de SAHOS en una población de obesos pertenecientes a un Programa de Obesidad y Cirugía Bariátrica de un hospital público de Montevideo. Metodología: Estudio observacional descriptivo de cohorte transversal. Se incluyeron pacientes en valoración preoperatoria desde abril 2015 a marzo 2020. Se les realizó una polisomnografía. Se evaluó la prevalencia de SAHOS y la relación con otros factores de riesgo cardiovascular. El análisis estadístico se realizó con SPSS versión 25.0. Resultados: Se estudiaron 358 pacientes con predominio del sexo femenino (86,3%), edad media de 42,8 ± 10,7 años y un índice de masa corporal (IMC) promedio de 50,1 ± 11,4 kg/m2. Se evidenció una prevalencia de SAHOS de 69%: 43,3% leve; 23,9% moderada y 32,8% severo. El Índice apnea hipopnea (IAH) se correlacionó positivamente con IMC (p ≤ 0,001). Se demostró la asociación de SAHOS con hipertensión arterial (HTA), diabetes 2 (DM2), sexo masculino e hipertrigliceridemia. Conclusiones: El SAHOS es altamente prevalente en la obesidad. Este estudio sugiere la realización de un screening en todos los obesos, así como su estudio con polisomnografía o poligrafía respiratoria a aquellos que vayan a someterse a una cirugía bariátrica.
Introduction: Obesity is a multifactorial epidemic disease that has been constantly increasing in recent years. It associates the development of multiple pathologies with increased morbidity and mortality, including obstructive sleep apnea and hypopnea syndrome (OSAHS). Objective: To study the prevalence of OSAHS in a population of obese patients belonging to an Obesity and Bariatric Surgery Program of a public hospital in Montevideo. Methodology: Observational descriptive cross-sectional study. Patients in preoperative evaluation were included from April 2015 to March 2020. A polysomnography was performed. The prevalence of OSAHS and the relationship with other cardiovascular risk factors were evaluated. Statistical analysis was performed with SPSS version 25.0. Results: 358 patients were studied, predominantly female (86.3%), mean age of 42.8 ± 10.7 years and mean BMI of 50.1 ± 11.4 kg/m2. A prevalence of OSAHS of 69% was evidenced: 43.3% mild; 23.9% moderate and 32.8% severe. The Apnea Hypopnea Index (AHI) was positively correlated with the Body Mass Index (BMI) (p=<0.001). The association of OSAHS with arterial hypertension (AHT), diabetes 2 (DM2), male gender and hypertriglyceridemia was demonstrated. Conclusions: OSAHS is highly prevalent in obesity. This study suggests screening all obese people, as well as polysomnography or respiratory polygraphy for those who are going to undergo bariatric surgery.
Introdução: A obesidade é uma doença epidêmica multifatorial que vem aumentando constantemente nos últimos anos. Associa o desenvolvimento de múltiplas patologias ao aumento da morbimortalidade, incluindo a síndrome da apneia e hipopneia obstrutiva do sono (SAHOS). Objetivo: Estudar a prevalência de SAHOS em uma população de pacientes obesos pertencentes a um Programa de Obesidade e Cirurgia Bariátrica de um hospital público de Montevidéu. Metodologia: Estudo observacional descritivo transversal. Os pacientes em avaliação pré-operatória foram incluídos de abril de 2015 a março de 2020. Foi realizada polissonografia. A prevalência de SAHOS e a relação com outros fatores de risco cardiovascular foram avaliadas. A análise estatística foi realizada com SPSS versão 25.0. Resultados: Foram estudados 358 pacientes, predominantemente do sexo feminino (86,3%), idade média de 42,8 ± 10,7 anos e IMC médio de 50,1 ± 11,4 kg/m2. Evidenciou-se prevalência de SAHOS de 69%: 43,3% leve; 23,9% moderado e 32,8% grave. O Índice de Apnéia e Hipopnéia (IAH) correlacionou-se positivamente com o Índice de Massa Corporal (IMC) (p=<0,001). Foi demonstrada a associação da SAHOS com hipertensão arterial (HA), diabetes 2 (DM2), sexo masculino e hipertrigliceridemia. Conclusões: A SAHOS é altamente prevalente na obesidade. Este estudo sugere a triagem de todos os obesos, bem como a polissonografia ou poligrafia respiratória para aqueles que serão submetidos à cirurgia bariátrica.
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Previous studies have shown that polyphenol consumption enhances recovery of the muscle after exercise-induced muscle damage (EIMD). However, EIMD markers have not been studied by sport type. The main aim of this research was to perform a systematic review to determine the efficacy of polyphenolic consumption in increasing muscle recovery for performing team sport skills. Eligible studies included, following PICOS structure, presented at least one of the following outcomes: maximal isometric voluntary contraction (MVIC); countermovement jump (CMJ); delayed onset muscle soreness (DOMS); 20 m sprint test; creatine kinase (CK); and C-reactive protein (hsCRP). A structured search was carried out following the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines. The risk of bias was assessed using the PEDro scale tool. The review showed a possibly positive impact of polyphenol consumption on recovery after EIMD in team sports athletes. No differences were found between sexes. Considering the limitations, there is moderate to very low certainty of polyphenol supplementation effects on recovery of team sport females and males. A dose of 60 mL/day, divided into two times per day, ingested for >7 days may present positive effects on muscle function and muscle soreness in team sport athletes. However, further investigation is required, specifically in females.
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Desempenho Atlético , Mialgia , Atletas , Desempenho Atlético/fisiologia , Proteína C-Reativa/metabolismo , Creatina Quinase/metabolismo , Feminino , Humanos , Masculino , Músculo Esquelético/metabolismo , Mialgia/tratamento farmacológico , Polifenóis/metabolismo , Polifenóis/farmacologia , Polifenóis/uso terapêutico , Esportes de EquipeRESUMO
Blueberry production is affected by fungal postharvest pathogens, including Botrytis cinerea and Alternaria alternata, the causative agents of gray mold disease and Alternaria rot, respectively. Biocontrol agents adapted to blueberries and local environments are not known to date. Here, we report on the search for and the identification of cultivable blueberry epiphytic bacteria with the potential to combat the aforementioned fungi. Native, blueberry-borne bacterial strains were isolated from a plantation in Tucumán, Argentina and classified based on 16S rRNA gene sequences. Antagonistic activities directed at B. cinerea and A. alternata were studied in vitro and in vivo. The 22 bacterial strains obtained could be attributed to eleven different genera: Rosenbergiella, Fictibacillus, Bacillus, Pseudomonas, Microbacterium, Asaia, Acinetobacter, Curtobacterium, Serratia, Sphingomonas and Xylophilus. Three strains displaying antagonistic impacts on the fungal pathogens were identified as Bacillus velezensis (BA3 and BA4) and Asaia spathodeae (BMEF1). These strains are candidates for biological control agents of local blueberry production and might provide a basis for the development of eco-friendly, sustainable alternatives to synthetic pesticides.
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One possible consequence of dentoalveolar trauma is the development of external inflammatory root resorption (EIRR), which represents an anatomic and microbiologic challenge for clinicians. This case report describes different strategies implemented for successful endodontic management of teeth with multiple EIRR lesions, highlighting the orthograde root canal filling using a tricalcium silicate-based material (Biodentine, Septodont, Saint-Maur-des-Fossés, France). A 17-year-old female patient presented with severe pain in the anterior maxillary teeth and a history of trauma. Two- and three-dimensional radiographic exams confirmed EIRR in three teeth, with a total of 11 EIRR lesions, three exhibiting communication with the root canal. Therefore, chemo-mechanical preparation complemented by ultrasonic activation of irrigants and some changes of intra-canal dressing with calcium hydroxide were performed to reduce the microbiologic load of the affected teeth as much as possible. Then, the canals were entirely filled with Biodentine to interrupt the root resorption process and strengthen the remaining root structure. A 60-month follow-up showed the disappearance of bone rarefactions and the complete repair of the 11 EIRR lesions. The favorable long-term response indicates the feasibility of using tricalcium silicate-based putty as part of orthograde endodontic treatment of teeth with EIRR and root perforations.
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Background: The World Health Organization (WHO) End TB strategy document 'Toward tuberculosis elimination: an action framework for low incidence countries'-like Canada- identifies screening and treatment of latent tuberculosis infection (LTBI) for groups at increased risk for TB disease as a priority, including newcomers from endemic countries. In 2015, the clients-centered model offered at a primary care facility for refugees, BridgeCare Clinic, Winnipeg, Canada was evaluated. The model included LTBI screening, assessment, and treatment, and originally offered 9-months of isoniazid as treatment. This mixed methods evaluation investigates LTBI program outcomes since the introduction of two short-course treatment regimens: 4-months of rifampin, and 3-months of isoniazid and rifapentine. Methods: This study combined a retrospective analysis of program administrative data with structured interviews of clinic staff. We included LTBI treatment eligibility, the treatment regimen offered, treatment initiation, and completed treatment from January 1, 2015 to August 6, 2020. Results: Seven hundred and one people were screened, and infection rates varied from 34.1% in 2015 to 53.3% in 2020. Most people living with LTBI came from high TB burden countries in Africa and South-East Asia WHO regions and were younger than 45 years old. Treatment eligibility increased 9% (75% in 2015 to 86% in 2016-2020) and most people diagnosed with LTBI took the short course treatments offered. There was an increase of 14.5% in treatment initiation (75.6 vs. 90.1%), and an increase of 8% in treatment completion (82.4 vs. 90.4%) after short-course regimens were introduced. The final model showed that the treatment regimen tends to affect the frequency of treatment completion, but there are other factors that influence this outcome, in this population. With the new treatments, BridgeCare Clinic achieved the 90% of treatment coverage, and the 90% treatment completion rate targets recommended in the End TB Strategy. Qualitative interviews with clinic staff further affirm the higher acceptability of the new treatments. Conclusion: While these results are limited to government-sponsored refugees in Winnipeg, they highlight the acceptability and value of short-course LTBI treatment as a possibility for reaching End TB targets in primary care settings.
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Tuberculose Latente , Refugiados , Humanos , Pessoa de Meia-Idade , Tuberculose Latente/tratamento farmacológico , Tuberculose Latente/epidemiologia , Isoniazida/uso terapêutico , Estudos Retrospectivos , Canadá/epidemiologia , Atenção Primária à SaúdeRESUMO
Structural maintenance of chromosome 5/6 (SMC5/6) complex is a crucial factor for preserving genome stability. Here, we show that mutants for several Arabidopsis (Arabidopsis thaliana) SMC5/6 complex subunits produce triploid offspring. This phenotype is caused by a meiotic defect leading to the production of unreduced male gametes. The SMC5/6 complex mutants show an absence of chromosome segregation during the first and/or the second meiotic division, as well as a partially disorganized microtubule network. Importantly, although the SMC5/6 complex is partly required for the repair of SPO11-induced DNA double-strand breaks, the nonreduction described here is SPO11-independent. The measured high rate of ovule abortion suggests that, if produced, such defects are maternally lethal. Upon fertilization with an unreduced pollen, the unbalanced maternal and paternal genome dosage in the endosperm most likely causes seed abortion observed in several SMC5/6 complex mutants. In conclusion, we describe the function of the SMC5/6 complex in the maintenance of gametophytic ploidy in Arabidopsis.
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Proteínas de Arabidopsis/genética , Arabidopsis/genética , Segregação de Cromossomos , Pólen/crescimento & desenvolvimento , Arabidopsis/crescimento & desenvolvimento , Proteínas de Arabidopsis/metabolismo , Quebras de DNA de Cadeia Dupla , Meiose , Pólen/genéticaRESUMO
Objetivo: Estudiar morfométricamente el complejo estilohioideo (CEH) mediante tomografía computarizada multicorte (TCM). Materiales y métodos: Investigación descriptiva, retrospectiva y transversal. La muestra estuvo conformada por 238 estudios de TCM, pertenecientes a pacientes de ambos sexos con edades entre 20 y 87 años, con indicación de tomografía para el macizo craneofacial. Se realizó la medición de la longitud del CEH en vistas laterales de reconstrucciones volumétricas en 3D. Se obtuvo la distribución de estos casos de acuerdo con edad, sexo, lateralidad, tipo de osificación y motivo de indicación del examen. Resultados: La longitud media del CEH fue de 30,66 ± 10,58 mm. Del total de la muestra, 127 (53,4%) individuos mostraron un CEH elongado; de estos, un 63,8% fueron mujeres y un 64,6% de los pacientes presentó un compromiso bilateral del complejo. La mayoría de los sujetos con un CEH elongado tenían edades comprendidas entre 30 y 59 años. El tipo de osificación encontrada con mayor frecuencia fue del tipo I (elongación continua). En cuanto al motivo de indicación del examen, la mayoría de los pacientes fueron referidos para estudio de la articulación temporomandibular. Conclusiones: La TCM es una herramienta útil en la identificación y el estudio morfométrico de la osificación del CEH, tanto en su longitud como tipo. El examen de un CEH osificado es importante para el diagnóstico diferencial de dolor cervicofacial y disfunción de la articulación temporomandibular. (AU)
Objective: tomography (MCT). Materials and methods: This was a descriptive, retrospective cross-sectional study. The sample was made up of 238 MCT studies performed in patients of both sexes between 20 to 87 years of age, with indication of tomography of the craniofacial complex. The length of the SHC was measured in lateral views of 3D volumetric reconstructions. The distribution of these cases was obtained according to age, sex, laterality, type and the reason for the examination. Results: The mean length of the SHC was 30.66 ± 10.58 mm. Of the total sample, 127 (53.4%) individuals showed an elongated SHC; of these, 63.8% were women and 64.6% of the patients presented a bilateral compromise of the complex. Most of the subjects with an elongated SHC were between 30 and 59 years old. The type of ossification most frequently found was type I (continuous elongation). Regarding the reason for the examination, most of the individuals were referred for study of the temporomandibular joint. Conclusions: MCT is a useful tool for the identification and morphometric study of ossification of the SHC, both in length and type. Examination of an ossified SHC is important for the differential diagnosis of cervico-facial pain and temporomandibular joint dysfunction. (AU)
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Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Osso Temporal , Tomografia Computadorizada Multidetectores , Osso Hioide , Epidemiologia Descritiva , Estudos Transversais , Estudos RetrospectivosRESUMO
INTRODUCTION: This study analyzed intra- and interobserver agreements during radiographic assessment of the different stages of root development using the dichotomous, Moorrees, Demirjian, and Cvek classifications, as well as the effect of the observer's level of experience on the result. METHODS: Two hundred eighty-five digital periapical radiographs were examined via visual inspection by 3 experienced and 3 nonexperienced observers (n = 6) under strict technological and viewing conditions. After observer calibration, determination of the presence or absence of an open apex and the assignment of a root development stage according to the different subdivisions of the 4 indexes were performed. This evaluation was carried out by each observer in duplicate in the first round (n = 8) and repeated in the second round (n = 8). The 16 examinations performed by each observer (N = 96) were analyzed to determine the percentage of concordance followed by intraobserver, interobserver, and global observer agreement using the kappa coefficient and a weighted kappa. Additionally, to determine the level of concordance between the visual determination of an open or closed apex and the apical foramen width measured in millimeters, a dichotomized kappa coefficient was applied. RESULTS: A good level of global observer agreement was found for the dichotomous, Demirjian, and Cvek classifications. However, a significantly low percentage of total concordance and global observer agreement (6.66% and 0.498, respectively) was obtained using the Moorrees classification, which was more pronounced among nonexperienced observers (0.247). Apical foramen width measurements indicated the presence of 143 roots with an open apex (50.2%) and 142 with a closed apex (49.8%), and the dichotomized kappa coefficient test revealed a good level of agreement during the visual determination of an open or closed apex (range, 0.611-0.636). CONCLUSIONS: The classifications of Cvek and Demirjian provided reliable results when determining the different stages of root development. In contrast, the Moorrees classification provided the lowest agreement values, with a significant negative effect among nonexperienced observers. Finally, the visual estimation of the presence (or absence) of an open apex provided a good level of concordance with the radiographic apical foramen width.
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Ápice Dentário , Humanos , Variações Dependentes do Observador , Reprodutibilidade dos Testes , Ápice Dentário/diagnóstico por imagemRESUMO
Worldwide, the green rot caused by Penicillium digitatum is one of the most aggressive postharvest diseases of lemons. Searching for sustainable alternatives to chemical fungicides, epiphytic yeasts as potential biocontrol agents were isolated from citrus fruits using a tailor-made selective medium. For disclosing their antagonistic potential against P. digitatum, obtained isolates were subjected to direct screening methods, both in vitro and in vivo. In the course of the primary in vitro screening that comprised dual culture assays, 43 yeast strains displaying antagonistic activities against the pathogen were selected. Subsequently, such strains were subjected to an in vivo screening that consisted of a microscale test, allowing the selection of six yeast strains for further analysis. In the final screening using macroscale in vivo tests, three strains (AcL2, AgL21, and AgL2) displaying the highest efficiencies to control P. digitatum were identified. The protection efficiencies in lemons were 80 (AcL2), 76.7 (AgL21), and 75% (AgL2). Based on sequence analysis of the PCR amplified D1/D2 domains of the 26S rRNA genes, they were identified as representatives of the species Clavispora lusitaniae. Interestingly, the strains exhibited a broad action spectrum among citrus fruits as they were also able to combat the green mold disease in grapefruit and two orange varieties. The direct screening methods applied in this study favored the recovery of efficient candidates for application as biological control agents to combat fungal infestations of citrus fruits.
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The effect of the incorporation of mineralizing Bacillus spp. on the characteristics of fluorescent organic matter (FDOM) in a recirculating aquaculture system (Nile tilapia-Stevia rebaudiana) was evaluated. EEM-PARAFAC analysis was used to determine the composition of the dissolved organic matter and to study its relationship with nitrogen transformation. The composition and antioxidant activity of Stevia leaves were used as indicators of the benefits of bacterial supplementation on nutrient absorption. Two systems were used, each consisting of a circular fish tank (1.7 m3) and six units of the nutrient film (0.18 m3). One system was supplemented with bacteria (BS), while the other was used as control (NBS). The inclusion of Bacillus spp. facilitated mineralization and the availability of total phosphorus (TP), K+, and nitrogen, and also controlled the total ammonia nitrogen (TAN) for 56 days without water exchange. FDOM was modeled by four components (3-humic-like, 1-protein-like), which were good indicators of the process of mineralization. The fluorescence intensity in the biofilter was significantly correlated with TP, K+, temperature, and the absorption coefficient a254. The fluorescence index (FI) was a good indicator of the process of nitrification. Plants from BS required 46.4% less NO3- and 47.8% less K+ compared to the control, and absorbed 45.1% more TP. BS-Stevia leaves produced 38.6% more reducing sugars, 28.6% more flavonoids, and 35.9% more glycosylated flavonoids than the control. The fish in the BS system reached a higher final weight than NBS, resulting in a 1 kg/m3 higher gross yield. Even so, it will be necessary to reduce the pH of the water to increase the antioxidant scavenging capacity of the plants.
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Bacillus , Stevia , Animais , Nitrogênio , Fósforo , Compostos FitoquímicosRESUMO
Every year and all over the world the fungal decay of fresh fruit and vegetables frequently generates substantial economic losses. Synthetic fungicides, traditionally used to efficiently combat the putrefactive agents, emerged, however, as the cause of environmental and human health issues. Given the need to seek for alternatives, several biological approaches were followed, among which those with killer yeasts stand out. Here, after the elaboration of the complex of problems, we explain the hitherto known yeast killer mechanisms and present the implementation of yeasts displaying such phenotype in biocontrol strategies for pre- or postharvest treatments to be aimed at combating postharvest fungal decay in numerous agricultural products.
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Fungal rots are one of the main causes of large economic losses and deterioration in the quality and nutrient composition of fruits during the postharvest stage. The yeast Clavispora lusitaniae 146 has previously been shown to efficiently protect lemons from green mold caused by Penicillium digitatum. In this work, the effect of yeast concentration and exposure time on biocontrol efficiency was assessed; the protection of various citrus fruits against P. digitatum by C. lusitaniae 146 was evaluated; the ability of strain 146 to degrade mycotoxin patulin was tested; and the effect of the treatment on the sensory properties of fruits was determined. An efficient protection of lemons was achieved after minimum exposure to a relatively low yeast cell concentration. Apart from lemons, the yeast prevented green mold in grapefruits, mandarins, oranges, and tangerines, implying that it can be used as a broad-range biocontrol agent in citrus. The ability to degrade patulin indicated that strain 146 may be suitable for the control of further Penicillium species. Yeast treatment did not alter the sensory perception of the aroma of fruits. These results corroborate the potential of C. lusitaniae 146 for the control of postharvest diseases of citrus fruits and indicate its suitability for industrial-scale fruit processing.
RESUMO
Only quite recently, we have shown that yeast strains Clavispora lusitaniae 146 and Pichia fermentans 27 can act as efficient biocontrol agents for combating postharvest fungal diseases in lemons. During postharvest and storage conditions, microorganisms are subject to different stress factors that could affect both their survival and their protective capacity. Understanding the tolerance of yeasts to environmental stress factors could support the future development and commercial application of biological control formulations based on such organisms. Thus, the impact of different stressors on the viability and protection efficiency of C. lusitaniae strain 146 and P. fermentans strain 27 was evaluated, and the yeasts were subjected to oxidative stress, thermal treatments, exposure to NaOCl, osmotic stress, and ultraviolet irradiation. Candida oleophila strain O served as the reference control. C. lusitaniae 146 was more resistant to H2O2 in plate assays; however, in liquid media there was no significant difference to the other strains. Strain 146 was less affected by NaOCl, being able to survive with 300 ppm. P. fermentans 27 was the strain most heavily affected by osmotic pressure, while strains 146 and strain O showed a similar adaptation. UV-B irradiation severely affected C. oleophila and P. fermentans, while C. lusitaniae was the most resistant. Strains 146 and 27 were similarly tolerant to thermal shocks, compared to the reference strain, which was less viable. In in vivo tests, exposure to 10 mM H2O2, 45°C or 200 ppm NaOCl prior to fruit inoculation, reduced the antagonistic activity against the pathogen Penicillium digitatum. However, in no case was the biocontrol efficiency reduced to less than 50%. As C. lusitaniae 146 demonstrated a great potential to combat P. digitatum under a wide range of conditions, the organism is a promising candidate as an effective and valuable alternative to toxic fungicides.
Assuntos
Citrus/microbiologia , Viabilidade Microbiana , Saccharomycetales/fisiologia , Citrus/crescimento & desenvolvimento , Estresse Oxidativo , Controle Biológico de Vetores , Saccharomycetales/metabolismo , TemperaturaRESUMO
The emergence of coronavirus disease 19 pandemic and novel research on the high transmissibility of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has raised controversies over the use of face masks to prevent community transmission. Specific regulations need to be fulfilled to use a face mask as part of the personal protective equipment and high quality of evidence supporting its use to prevent respiratory viral infections, including SARS-CoV-2, is lacking. However, its widespread use is becoming a standard practice in some countries and discrepancies between health authorities on their policy have led to controversy. The aim of this review is to provide an outlook on recent research in this matter and areas of opportunity.