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Aerobic respiration is the main energy source for most eukaryotes, and efficient mitochondrial energy transfer greatly influences organismal fitness. To survive environmental changes, cells have evolved to adjust their biochemistry. Thus, measuring energy metabolism at the subcellular level can enhance our understanding of individual performance, population dynamics, and species distribution ranges. We investigated three important metabolic traits at the subcellular level in five lacertid lizard species sampled from different elevations, from sea level up to 2000 m. We examined hemoglobin concentration, two markers of oxidative stress (catalase activity and carbonyl concentration) and maximum rate of metabolic respiration at the subcellular level (potential metabolic activity at the electron transport system). The traits were analysed in laboratory acclimated adult male lizards to investigate the adaptive metabolic responses to the variable environmental conditions at the local sampling sites. Potential metabolic activity at the cellular level was measured at four temperatures - 28 °C, 30 °C, 32 °C and 34 °C - covering the range of preferred body temperatures of the species studied. Hemoglobin content, carbonyl concentration and potential metabolic activity did not differ significantly among species. Interspecific differences were found in the catalase activity, Potential metabolic activity increased with temperature in parallel in all five species. The highest response of the metabolic rate with temperature (Q10) and Arrhenius activation energy (Ea) was recorded in the high-mountain species Iberolacerta monticola.
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This study aimed to develop an analytical method using HS-SPME/GC-MS to determine the volatile organic compound (VOC) profiles and evaluate the sensory attributes of cocoa honey from four cocoa varieties (CCN51, PS1319, SJ02, and Parazinho). Using a multivariate factorial experimental design, the HS-SPME/GC-MS method was optimized to determine the VOC profiles. Twenty previously trained tasters participated in the ranking descriptive analysis, while 108 consumers participated in the acceptance and purchase intention tests. A total of 84 volatile organic compounds were identified from various chemical classes, including acids, alcohols, aldehydes, esters, ketones, monoterpenes, oxygenated monoterpenoids, sesquiterpenes, and oxygenated sesquiterpenoids. Palmitic acid was the compound found in the highest concentration in all varieties (5.13-13.10%). Multivariate analysis tools identified key compounds for differentiation and grouping of the samples. The results revealed that the variety significantly influenced both the VOCs' concentrations and sensory profiles. The CCN51, PS1319, and SJ02 varieties exhibited the highest diversity of VOCs and sensory attributes. Notably, the SJ02 and CCN51 varieties demonstrated superior acceptability and purchase intention, with means ranging from 7.21 and 7.08 to 3.71 and 3.56, respectively. These results indicate their potential as promising sources of cocoa honey for the food industry.
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Cacau , Cromatografia Gasosa-Espectrometria de Massas , Mel , Microextração em Fase Sólida , Compostos Orgânicos Voláteis , Compostos Orgânicos Voláteis/análise , Cacau/química , Cromatografia Gasosa-Espectrometria de Massas/métodos , Mel/análise , Microextração em Fase Sólida/métodos , Humanos , Adulto , Feminino , MasculinoRESUMO
INTRODUCTION/AIMS: Objective and practical biomarkers to determine the need for gastrostomy in patients with amyotrophic lateral sclerosis (ALS) are lacking. Tongue pressure (TP) is a promising biomarker because it is associated with bulbar dysfunction. The aims of this study were to evaluate the association of TP with the need for gastrostomy, and to determine its optimal cut-off value. METHODS: This prospective observational study included participants with ALS taking nutrition orally. TP was evaluated using the Iowa Oral Performance Instrument. Need for gastrostomy as determined by a multidisciplinary team during a 12-month follow up period was recorded. Associations between TP and need for gastrostomy placement were performed. ROC curve analysis determined the optimal cut-off value of TP to predict gastrostomy. RESULTS: Of 208 screened participants, 119 were included. Gastrostomy was indicated in 45% (53), in a 12-month follow up period. TP of ≤20 kPA was a strong predictor of gastrostomy indication (OR 11.8, CI 95% [4.61, 34.7], p < .001). The association persisted even after adjustment for weight loss, pneumonia, prolonged feeding duration, Revised ALS Functional Rating Scale score, and American Speech-Language-Hearing Association scale score (OR 4.51, CI 95% [1.50, 14.9], p = .009). By receiver operating characteristic curve analysis, 20 kPA represented the optimal cut-off value (sensitivity 0.75, specificity 0.89). DISCUSSION: TP is a strong independent predictor of gastrostomy indication in the subsequent 12 months in patients with ALS, with good sensitivity and specificity at a cutoff value of ≤20 kPA, suggesting that it may be a promising biomarker in clinical practice.
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Esclerose Lateral Amiotrófica , Gastrostomia , Língua , Humanos , Esclerose Lateral Amiotrófica/fisiopatologia , Esclerose Lateral Amiotrófica/terapia , Feminino , Masculino , Pessoa de Meia-Idade , Idoso , Estudos Prospectivos , Língua/fisiopatologia , Pressão , Curva ROC , SeguimentosRESUMO
INTRODUCTION: Physical activity and exercise are protective factors for physical and cognitive decline in older adults, but recent studies reveal that a large percentage of this population do not practice exercise at the levels recommended by international guidelines. The frequency, intensity, type, time, volume, and progression (FITT-VP) principles are a widely used method for prescribing physical exercise, allowing the development of a personalized exercise program that meets the needs of each individual. OBJECTIVES: This masterclass is intended to serve as a professional application tool for physical therapists who prescribe physical exercise for older adults. We present a section for each FITT-VP principle to facilitate handling these principles individually when prescribing exercise for this population. METHODS: Review of the scientific literature and international guidelines on the prescription of physical exercises for older adults. RESULTS: Aerobic, mobility, resistance, balance, and flexibility exercises, as well as functional training, should be included in an exercise program for older adults, which should be progressed using different methods for each of the exercise modalities. CONCLUSIONS: An exercise program for older adults should integrate different exercise modalities. Exercise progression should be performed following the FITT-VP principles and some specific progression factors recommended for each exercise modality. SIGNIFICANCE: Considering the challenge faced by clinicians in designing a viable exercise program for older adults that responds to international recommendations, with this masterclass we hope to help physical therapists to plan an exercise program that is feasible and at the same time, responds to the expected needs of this population.
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This study explored the impact of a sensory processing assessment, recommendations and feedback process on the functioning at school and after-hours environments of children who had been traumatised by abuse. A mixed methods design (Schoonenboom & Johnson, 2017) was utilized incorporating pre (12 months prior) and post (four to eight months after the report) repeated child focused measure, alongside thematic analysis of participants qualitative survey feedback. The methodology included two stages: firstly, an occupational therapy assessment of young people referred by Own Organisation clinicians for a sensory processing assessment and secondly, an evaluation was conducted of the impact of occupational therapy on the young person's behaviour and their carers. The study found significant improvement in family life and relationships as well as a reduction in impairment as evidenced by decreases in HoNOSCA scores across problems with family life and relationships, non-accidental self-injury, problems with emotional and related symptoms, poor school attendance and on the social subscale. These findings were supported by clinician participant reports. A sensory processing assessment provided young people, their carers and teachers with information which contributed to environmental adaptations. These environmental adaptations were associated with improved functioning and behaviour of young people impacted by child abuse. It is recommended future research attempt to replicate and extend our understanding of how sensory processing assessments and interventions can increase children's wellbeing. Supplementary Information: The online version contains supplementary material available at 10.1007/s40653-023-00607-0.
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Collapsing glomerulopathy (CG) is most often associated with fast progression to kidney failure with an incidence apparently higher in Brazil than in other countries. However, the reason for this occurrence is unknown. To better understand this, we performed an integrated analysis of clinical, histological, therapeutic, causative genetic and genetic ancestry data in a highly genetically admixed cohort of 70 children and adult patients with idiopathic CG (ICG). The disease onset occurred at 23 (interquartile range: 17-31) years and approximately half of patients progressed to chronic kidney disease requiring kidney replacement therapy (CKD-KRT) 36 months after diagnosis. Causative genetic bases, assessed by targeted-gene panel or whole-exome sequencing, were identified in 58.6% of patients. Among these cases, 80.5% harbored APOL1 high-risk genotypes (HRG) and 19.5% causative Mendelian variants (MV). Self-reported non-White patients more frequently had HRG. MV was an independent risk factor for progression to CKD-KRT by 36 months and the end of follow-up, while remission was an independent protective factor. All patients with HRG manifested CG at 9-44 years of age, whereas in those with APOL1 low-risk genotype, the disease arose throughout life. HRGs were associated with higher proportion of African genetic ancestry. Novel causative MVs were identified in COL4A5, COQ2 and PLCE1 and previously described causative MVs were identified in MYH9, TRPC6, COQ2, COL4A3 and TTC21B. Three patients displayed HRG combined with a variant of uncertain significance (ITGB4, LAMA5 or PTPRO). MVs were associated with worse kidney prognosis. Thus, our data reveal that the genetic status plays a major role in ICG pathogenesis, accounting for more than half of cases in a highly admixed Brazilian population.
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Apolipoproteína L1 , Insuficiência Renal Crônica , Adulto , Criança , Humanos , Apolipoproteína L1/genética , Genótipo , Rim/patologia , Insuficiência Renal Crônica/epidemiologia , Insuficiência Renal Crônica/genética , Insuficiência Renal Crônica/patologia , Fatores de Risco , Adolescente , Adulto JovemRESUMO
Norovirus is one of the largest causes of gastroenteritis worldwide, and Hepatitis E virus (HEV) is an emerging pathogen that has become the most dominant cause of acute viral hepatitis in recent years. The presence of norovirus and HEV has been reported within wastewater in many countries previously. Here we used amplicon deep sequencing (metabarcoding) to identify norovirus and HEV strains in wastewater samples from England collected in 2019 and 2020. For HEV, we sequenced a fragment of the RNA-dependent RNA polymerase (RdRp) gene targeting genotype three strains. For norovirus, we sequenced the 5' portion of the major capsid protein gene (VP1) of genogroup II strains. Sequencing of the wastewater samples revealed eight different genotypes of norovirus GII (GII.2, GII.3, GII.4, GII.6, GII.7, GII.9, GII.13 and GII.17). Genotypes GII.3 and GII.4 were the most commonly found. The HEV metabarcoding assay was able to identify HEV genotype 3 strains in some samples with a very low viral concentration determined by RT-qPCR. Analysis showed that most HEV strains found in influent wastewater were typed as G3c and G3e and were likely to have originated from humans or swine. However, the small size of the HEV nested PCR amplicon could cause issues with typing, and so this method is more appropriate for samples with high CTs where methods targeting longer genomic regions are unlikely to be successful. This is the first report of HEV RNA in wastewater in England. This study demonstrates the utility of wastewater sequencing and the need for wider surveillance of norovirus and HEV within host species and environments.
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Infecções por Caliciviridae , Vírus da Hepatite E , Sequenciamento por Nanoporos , Norovirus , Humanos , Animais , Suínos , Águas Residuárias , Vírus da Hepatite E/genética , Norovirus/genética , Genótipo , Filogenia , Fezes , Inglaterra , RNA Viral/genéticaRESUMO
Body coloration in ectotherms serves multiple biological functions, including avoiding predators, communicating with conspecific individuals, and involvement in thermoregulation. As ectotherms rely on environmental sources of heat to regulate their internal body temperature, stable melanistic body coloration or color change can be used to increase or decrease heat absorption and heat exchange with the environment. While melanistic coloration for thermoregulation functions to increase solar radiation absorption and consequently heating in many diurnal ectotherms, research on crepuscular and nocturnal ectotherms is lacking. Since crepuscular and nocturnal ectotherms generally absorb heat from the substrate, in these organisms melanistic coloration may have other primary functions beside thermoregulation. As such, in this work we hypothesized that the proportion of dorsal melanistic body coloration would not influence heating and cooling rates in the crepuscular gecko, Eublepharis macularius, and that changes in environmental temperature would not trigger color changes in this species. Temperature measurements of the geckos and of the environment were taken using infrared thermography and temperature loggers. Color data were obtained using objective photography and a newly developed custom software package. We found that body temperature reflected substrate temperatures, and that the proportion of melanistic coloration has no influence on heating or cooling rates or on color changes. These findings support that melanistic coloration in E. macularius may not be used for thermoregulation and strengthen the hypothesis that in animals active in low light conditions, melanistic coloration may be used instead for camouflage or other functions.
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Regulação da Temperatura Corporal , Lagartos , Animais , Lagartos/fisiologia , Temperatura Corporal , Temperatura , Temperatura AltaRESUMO
Intracellular heme formation and trafficking are fundamental processes in living organisms. Bacteria and archaea utilize three biogenesis pathways to produce iron protoporphyrin IX (heme b) that diverge after the formation of the common intermediate uroporphyrinogen III (uro'gen III). In this study, we identify and provide a detailed characterization of the enzymes involved in the transformation of uro'gen III into heme in Campylobacter jejuni, demonstrating that this bacterium utilizes the protoporphyrin-dependent (PPD) pathway. In general, limited knowledge exists regarding the mechanisms by which heme b reaches its target proteins after this final step. Specifically, the chaperones necessary for trafficking heme to prevent the cytotoxic effects associated with free heme remain largely unidentified. In C. jejuni, we identified a protein named CgdH2 that binds heme with a dissociation constant of 4.9 ± 1.0 µM, and this binding is impaired upon mutation of residues histidine 45 and 133. We demonstrate that C. jejuni CgdH2 establishes protein-protein interactions with ferrochelatase, suggesting its role in facilitating heme transfer from ferrochelatase to CgdH2. Furthermore, phylogenetic analysis reveals that C. jejuni CgdH2 is evolutionarily distinct from the currently known chaperones. Therefore, CgdH2 is the first protein identified as an acceptor of intracellularly formed heme, expanding our knowledge of the mechanisms underlying heme trafficking within bacterial cells.
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The armoured dinoflagellate Alexandrium can be found throughout many of the world's temperate and tropical marine environments. The genus has been studied extensively since approximately half of its members produce a family of potent neurotoxins, collectively called saxitoxin. These compounds represent a significant threat to animal and environmental health. Moreover, the consumption of bivalve molluscs contaminated with saxitoxin poses a threat to human health. The identification of Alexandrium cells collected from sea water samples using light microscopy can provide early warnings of a toxic event, giving harvesters and competent authorities time to implement measures that safeguard consumers. However, this method cannot reliably resolve Alexandrium to a species level and, therefore, is unable to differentiate between toxic and non-toxic variants. The assay outlined in this study uses a quick recombinase polymerase amplification and nanopore sequencing method to first target and amplify a 500 bp fragment of the ribosomal RNA large subunit and then sequence the amplicon so that individual species from the Alexandrium genus can be resolved. The analytical sensitivity and specificity of the assay was assessed using seawater samples spiked with different Alexandrium species. When using a 0.22 µm membrane to capture and resuspend cells, the assay was consistently able to identify a single cell of A. minutum in 50 mL of seawater. Phylogenetic analysis showed the assay could identify the A. catenella, A. minutum, A. tamutum, A. tamarense, A. pacificum, and A. ostenfeldii species from environmental samples, with just the alignment of the reads being sufficient to provide accurate, real-time species identification. By using sequencing data to qualify when the toxic A. catenella species was present, it was possible to improve the correlation between cell counts and shellfish toxicity from r = 0.386 to r = 0.769 (p ≤ 0.05). Furthermore, a McNemar's paired test performed on qualitative data highlighted no statistical differences between samples confirmed positive or negative for toxic species of Alexandrium by both phylogenetic analysis and real time alignment with the presence or absence of toxins in shellfish. The assay was designed to be deployed in the field for the purposes of in situ testing, which required the development of custom tools and state-of-the-art automation. The assay is rapid and resilient to matrix inhibition, making it suitable as a potential alternative detection method or a complementary one, especially when applying regulatory controls.
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Dinoflagellida , Sequenciamento por Nanoporos , Animais , Humanos , Dinoflagellida/genética , Saxitoxina/toxicidade , Saxitoxina/genética , Recombinases/genética , FilogeniaRESUMO
Earlier reviews to discover research on interventions for children after neglect have concluded little was available, despite the well-documented prevalence and harmful effects of neglect on children. We revisited this question through a systematic literature review to discover the state of research on interventions for children who have experienced neglect. We searched MEDLINE, PsycINFO, ERIC, Sociological Abstracts and EMBASE for studies published between 2003 and 2021. Studies were included if neglect could be distinguished, and child outcomes reported. Eight reports describing six studies about six interventions were identified. These studies differed in interventions, age-groups, definitions of neglect, and outcomes. Four studies reported positive child outcomes though with varying degree of quality. More research is needed to inform a coherent theory of change following neglect. There remains an urgent need for research on interventions to help children recover from neglect.
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Imaging two or more fluorescent biosensors in the same living cell can reveal the spatiotemporal coordination of protein activities. However, using multiple Förster resonance energy transfer (FRET) biosensors together is challenging due to toxicity and the need for orthogonal fluorophores. Here we generate a biosensor component that binds selectively to the activated conformation of three different proteins. This enabled multiplexed FRET with fewer fluorophores, and reduced toxicity. We generated this MultiBinder (MB) reagent for the GTPases RhoA, Rac1, and Cdc42 by combining portions of the downstream effector proteins Pak1 and Rhotekin. Using FRET between mCherry on the MB and YPet or mAmetrine on two target proteins, the activities of any pair of GTPases could be distinguished. The MB was used to image Rac1 and RhoA together with a third, dye-based biosensor for Cdc42. Quantifying effects of biosensor combinations on the frequency, duration, and velocity of cell protrusions and retractions demonstrated reduced toxicity. Multiplexed imaging revealed signaling hierarchies between the three proteins at the cell edge where they regulate motility.
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Técnicas Biossensoriais , Proteína cdc42 de Ligação ao GTP , Proteína cdc42 de Ligação ao GTP/metabolismo , Proteína rhoA de Ligação ao GTP/metabolismo , Transdução de Sinais , Transferência Ressonante de Energia de Fluorescência/métodos , Extensões da Superfície Celular , Corantes , Técnicas Biossensoriais/métodos , Proteínas rac1 de Ligação ao GTP/metabolismo , Proteínas rho de Ligação ao GTP/metabolismoRESUMO
Individuals infected with Leishmania (L.) chagasi may present different asymptomatic and symptomatic stages of infection, which vary in the clinical-immunological profiles that can be classified as asymptomatic infection (AI), subclinical resistant infection (SRI), indeterminate initial infection (III), subclinical oligosymptomatic infection (SOI), and symptomatic infection (SI) (=American visceral leishmaniasis, AVL). However, little is known about the molecular differences between individuals having each profile. Here, we performed whole-blood transcriptomic analyses of 56 infected individuals from Pará State (Brazilian Amazon), covering all five profiles. We then identified the gene signatures of each profile by comparing their transcriptome with those of 11 healthy individuals from the same area. Symptomatic individuals with SI (=AVL) and SOI profiles showed higher transcriptome perturbation when compared to those asymptomatic III, AI and SRI profiles, suggesting that disease severity may be associated with greater transcriptomic changes. Although the expression of many genes was altered on each profile, very few genes were shared among the profiles. This indicated that each profile has a unique gene signature. The innate immune system pathway was strongly activated only in asymptomatic AI and SRI profiles, suggesting the control of infection. In turn, pathways such as MHC Class II antigen presentation and NF-kB activation in B cells seemed to be specifically induced in symptomatic SI (=AVL) and SOI profiles. Moreover, cellular response to starvation was down-regulated in those symptomatic profiles. Overall, this study revealed five distinct transcriptional patterns associated to the clinical-immunological (symptomatic and asymptomatic) profiles of human L. (L.) chagasi-infection in the Brazilian Amazon.
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The production, harvesting and safe consumption of bivalve molluscs can be disrupted by biological hazards that can be divided into three categories: (1) biotoxins produced by naturally occurring phytoplankton that are bioaccumulated by bivalves during filter-feeding, (2) human pathogens also bioaccumulated by bivalves and (3) bivalve pathogens responsible for disease outbreaks. Environmental changes caused by human activities, such as climate change, can further aggravate these challenges. Early detection and accurate quantification of these hazards are key to implementing measures to mitigate their impact on production and safeguard consumers. This review summarises the methods currently used and the technological advances in the detection of biological hazards affecting bivalves, for the screening of known hazards and discovery of new ones.
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Bioacumulação , Bivalves , Toxinas Marinhas , Animais , Toxinas Marinhas/análiseRESUMO
The Bacteroides thetaiotaomicron has developed a consortium of enzymes capable of overcoming steric constraints and degrading, in a sequential manner, the complex rhamnogalacturonan II (RG-II) polysaccharide. BT0996 protein acts in the initial stages of the RG-II depolymerisation, where its two catalytic modules remove the terminal monosaccharides from RG-II side chains A and B. BT0996 is modular and has three putative carbohydrate-binding modules (CBMs) for which the roles in the RG-II degradation are unknown. Here, we present the characterisation of the module at the C-terminal domain, which we designated BT0996-C. The high-resolution structure obtained by X-ray crystallography reveals that the protein displays a typical ß-sandwich fold with structural similarity to CBMs assigned to families 6 and 35. The distinctive features are: 1) the presence of several charged residues at the BT0996-C surface creating a large, broad positive lysine-rich patch that encompasses the putative binding site; and 2) the absence of the highly conserved binding-site signatures observed in CBMs from families 6 and 35, such as region A tryptophan and region C asparagine. These findings hint at a binding mode of BT0996-C not yet observed in its homologues. In line with this, carbohydrate microarrays and microscale thermophoresis show the ability of BT0996-C to bind α1-4-linked polygalacturonic acid, and that electrostatic interactions are essential for the recognition of the anionic polysaccharide. The results support the hypothesis that BT0996-C may have evolved to potentiate the action of BT0996 catalytic modules on the complex structure of RG-II by binding to the polygalacturonic acid backbone sequence.
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Candida albicans is a human commensal fungus and the etiologic agent of nosocomial infections in immunocompromised individuals. Candida spp. is the most studied human fungal pathogen, and the mechanisms by which this fungus can evade the immune system affecting immunosuppressed individuals have been extensively studied. Most of these studies focus on different species of Candida, and there is much to be understood in virulence variability among lineages, specifically different C. albicans clinical isolates. To better understand the main mechanisms of its virulence variability modulated in C. albicans clinical isolates, we characterized L3881 lineage, which has been previously classified as hypovirulent, and SC5314 lineage, a virulent wild-type control, by using both in vitro and in vivo assays. Our findings demonstrated that L3881 presented higher capacity to avoid macrophage phagocytosis and higher resistance to oxidative stress than the wild type. These characteristics prevented higher mortality rates for L3881 in the animal model of candidiasis. Conversely, L3881 has been able to induce an upregulation of pro-inflammatory mediators both in vitro and in vivo. These results indicated that in vitro and in vivo functional characterizations are necessary for determination of virulence in different clinical isolates due to its modulation in the host-pathogen interactions.
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Sugarcane is a widely cultivated crop in Brazil and in many parts of the world. However, the red rot causes huge losses due to the reduction of sucrose and deterioration of the juice. The aim of this study was to identify Colletotrichum species associated with the red rot through polyphasic approaches; which included phylogenetic, morpho-cultural analyzes and pathogenicity tests. Nine isolates from the states of Alagoas and two from São Paulo, Brazil, were preliminary analyzed with the glyceraldehyde-3 phosphate dehydrogenase gene (GAPDH), as an initial measure for species diversity. Later on, the representative isolates of each species were sequenced with the ß-tubulin (TUB2) gene, calmodulin (CAL), DNA lyase (APN2/MAT IGS) and the ITS-rDNA region. Morphocultural characterization was performed by evaluating the mycelial growth rate (MGR), colony appearance and the shape and size of 50 conidia and appressoria. For the pathogenicity test asymptomatic leaves and stalks of sugarcane were tested with and without injuries. Phylogenetic analysis associated with morphocultural characteristics and the pathogenicity test of the eleven isolates revealed three Colletotrichum species: Colletotrichum falcatum (8 isolates), Colletotrichum siamense (1 isolate) and Colletotrichum plurivorum (2 isolates) causing the red rot disease in sugar cane. All species were pathogenic in wounded leaves and stalks, being C. falcatum the one causing the largest lesions (1.12 cm) in leaves and C. plurivorum in stalks (0.67 cm). Therefore, this study confirms the association of C. falcatum as a sugarcane pathogen and records for the first time worldwide the occurrence of C. siamense and C. plurivorum associated with this host.
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Colletotrichum , Saccharum , Brasil , Filogenia , Doenças das PlantasRESUMO
In the last decade, declines in the population of wild blue mussels Mytilus edulis in the Tamar estuary (United Kingdom) have been noted. In archived samples collected from 2013 to 2019, between 7% (in 2013) and 18% (in 2019) showed large granulocytoma and haemocytic infiltration in the interstitial tissue of the digestive gland. Four samples were selected for 16S rRNA gene Nanopore sequencing. A consensus sequence of 1449 bp showed nucleotide similarities between 99.93-100% with published sequences of Francisella halioticida. In situ hybridisation (ISH) confirmed the presence of F. halioticida DNA within individual granulocytes of granulocytomas and also in prokaryotic-like inclusion bodies within the digestive epithelial cells. The design of diagnostic tests for surveillance of F. halioticida, including more specific ISH probes and sequencing the genome of the isolates infecting mussels, will shed more light on the pathogenicity and spread of this pathogen.
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Host, pathogen, and environment are determinants of the disease triangle, the latter being a key driver of disease outcomes and persistence within a community. The dinoflagellate genus Hematodinium is detrimental to crustaceans globally - considered to suppress the innate defences of hosts, making them more susceptible to co-infections. Evidence supporting immune suppression is largely anecdotal and sourced from diffuse accounts of compromised decapods. We used a population of shore crabs (Carcinus maenas), where Hematodinium sp. is endemic, to determine the extent of collateral infections across two distinct environments (open-water, semi-closed dock). Using a multi-resource approach (PCR, histology, haematology, population genetics, eDNA), we identified 162 Hematodinium-positive crabs and size/sex-matched these to 162 Hematodinium-free crabs out of 1191 analysed. Crabs were interrogated for known additional disease-causing agents; haplosporidians, microsporidians, mikrocytids, Vibrio spp., fungi, Sacculina, trematodes, and haemolymph bacterial loads. We found no significant differences in occurrence, severity, or composition of collateral infections between Hematodinium-positive and Hematodinium-free crabs at either site, but crucially, we recorded site-restricted blends of pathogens. We found no gross signs of host cell immune reactivity towards Hematodinium in the presence or absence of other pathogens. We contend Hematodinium sp. is not the proximal driver of co-infections in shore crabs, which suggests an evolutionary drive towards latency in this environmentally plastic host.
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Braquiúros/parasitologia , Dinoflagellida/fisiologia , Animais , Bactérias/classificação , Bactérias/isolamento & purificação , Braquiúros/imunologia , Braquiúros/microbiologia , Feminino , Helmintos/classificação , Helmintos/isolamento & purificação , Interações Hospedeiro-Patógeno , MasculinoRESUMO
The cure fraction models are intended to analyze lifetime data from populations where some individuals are immune to the event under study, and allow a joint estimation of the distribution related to the cured and susceptible subjects, as opposed to the usual approach ignoring the cure rate. In situations involving small sample sizes with many censored times, the detection of nonfinite coefficients may arise via maximum likelihood. This phenomenon is commonly known as monotone likelihood (ML), occurring in the Cox and logistic regression models when many categorical and unbalanced covariates are present. An existing solution to prevent the issue is based on the Firth correction, originally developed to reduce the estimation bias. The method ensures finite estimates by penalizing the likelihood function. In the context of mixture cure models, the ML issue is rarely discussed in the literature; therefore, this topic can be seen as the first contribution of our paper. The second major contribution, not well addressed elsewhere, is the study of the ML issue in cure mixture modeling under the flexibility of a semiparametric framework to handle the baseline hazard. We derive the modified score function based on the Firth approach and explore finite sample size properties of the estimators via a Monte Carlo scheme. The simulation results indicate that the performance of coefficients related to the binary covariates are strongly affected to the imbalance degree. A real illustration, in the melanoma dataset, is discussed using a relatively novel data set collected in a Brazilian university hospital.