Psychometric properties of the Functional Literacy Questionnaire among Portuguese adolescents.

BACKGROUND: Robust tools to assess self-reported adolescent functional health literacy are lacking. In Portugal, the only available tool is the Newest Vital Sign for Portuguese adolescents (NVS-PTeen), though presenting modest validity and reliability properties. A new instrument-the Functional Literacy Questionnaire (FLiQ)-was developed, inspired by the NVS-PTeen, but following the European Regulation for food labeling and targeting a balanced assessment of numeracy and verbal comprehension skills. This study aimed to evaluate several psychometric properties of the FLiQ when administered to Portuguese adolescents. METHODS: We conducted a longitudinal observational study with three phases: (1) Delphi panel with health literacy experts; (2) self-administration of FLiQ and NVS-PTeen to adolescents in 7th to 9th grades; and (3) re-administration of FLiQ four weeks after baseline, to the same group of participants. RESULTS: FLiQ's content validity was excellent, with an Average-Content Validity Index of .95. Overall, 372 adolescents (50.3% girls) aged between 12-17 years (median age: 13) participated in the study. Of these, 150 completed the test-retest assessment. Internal consistency was good (Kuder-Richardson Fornula-20 = .70), as well as test-retest reliability (Intraclass Coefficient Correlation = .82). FLiQ total score was weakly correlated with the school year (rho = .174), and moderately with Portuguese (rho = .348) and Mathematics grades (rho = .333). Factor analysis indicated a two-dimension structure, reflecting numeracy and verbal comprehension skills. Item response theory analysis revealed differences in difficulty and discrimination capacity among items, all with adequate fit values. CONCLUSION: FLiQ is a valid and reliable tool. It can be used to monitor functional health literacy levels in Portuguese adolescents.

Protocol for quantification of intercellular connection transmission in ebolavirus infections using ImageJ.

Previous work demonstrates that ebolaviruses can spread to neighboring cells through intercellular connections. Here, we present a protocol to quantify the intercellular spread of ebolaviruses via immunofluorescence. We describe steps for cell plating, Bundibugyo virus infection, and adding a neutralizing antibody. We detail procedures for quantitative microscopy assay using ebolavirus immunodetection. Strong virus accumulation around the plasma membrane leads to high fluorescence signal preventing quantification of viral spread based on signal intensity. This protocol minimizes the impact of this bias. For complete details on the use and execution of this protocol, please refer to Santos et al.1.

In silico evaluation of cell therapy in acute versus chronic infarction: role of automaticity, heterogeneity and Purkinje in human.

Human-based modelling and simulation offer an ideal testbed for novel medical therapies to guide experimental and clinical studies. Myocardial infarction (MI) is a common cause of heart failure and mortality, for which novel therapies are urgently needed. Although cell therapy offers promise, electrophysiological heterogeneity raises pro-arrhythmic safety concerns, where underlying complex spatio-temporal dynamics cannot be investigated experimentally. Here, after demonstrating credibility of the modelling and simulation framework, we investigate cell therapy in acute versus chronic MI and the role of cell heterogeneity, scar size and the Purkinje system. Simulations agreed with experimental and clinical recordings from ionic to ECG dynamics in acute and chronic infarction. Following cell delivery, spontaneous beats were facilitated by heterogeneity in cell populations, chronic MI due to tissue depolarisation and slow sinus rhythm. Subsequent re-entrant arrhythmias occurred, in some instances with Purkinje involvement and their susceptibility was enhanced by impaired Purkinje-myocardium coupling, large scars and acute infarction. We conclude that homogeneity in injected ventricular-like cell populations minimises their spontaneous beating, which is enhanced by chronic MI, whereas a healthy Purkinje-myocardium coupling is key to prevent subsequent re-entrant arrhythmias, particularly for large scars.

Satellitome analysis on the pale-breasted thrush Turdus leucomelas (Passeriformes; Turdidae) uncovers the putative co-evolution of sex chromosomes and satellite DNAs.

Do all birds' sex chromosomes follow the same canonical one-way direction of evolution? We combined cytogenetic and genomic approaches to analyze the process of the W chromosomal differentiation in two selected Passeriform species, named the Pale-breasted Thrush Turdus leucomelas and the Rufous-bellied thrush T. rufiventris. We characterized the full catalog of satellite DNAs (satellitome) of T. leucomelas, and the 10 TleSatDNA classes obtained together with 16 microsatellite motifs were in situ mapped in both species. Additionally, using Comparative Genomic Hybridization (CGH) assays, we investigated their intragenomic variations. The W chromosomes of both species did not accumulate higher amounts of both heterochromatin and repetitive sequences. However, while T. leucomelas showed a heterochromatin-poor W chromosome with a very complex evolutionary history, T. rufiventris showed a small and partially heterochromatic W chromosome that represents a differentiated version of its original autosomal complement (Z chromosome). The combined approach of CGH and sequential satDNA mapping suggest the occurrence of a former W-autosomal translocation event in T. leucomelas, which had an impact on the W chromosome in terms of sequence gains and losses. At the same time, an autosome, which is present in both males and females in a polymorphic state, lost sequences and integrated previously W-specific ones. This putative W-autosomal translocation, however, did not result in the emergence of a multiple-sex chromosome system. Instead, the generation of a neo-W chromosome suggests an unexpected evolutionary trajectory that deviates from the standard canonical model of sex chromosome evolution.

Etomidate as an anesthetic in Colossoma macropomum: Behavioral and electrophysiological data complement each other as a tool to assess anesthetic safety.

The use of anesthetic agents in the management of fish in fish farming or ornamental fish breeding aims to minimize stress and promote animal welfare. Therefore, this study aims to investigate behavioral, electrocardiographic, and ventilatory characteristics of tambaquis exposed to anesthetic baths with etomidate. The study was conducted with juvenile tambaquis (27.38 ± 3.5g) n = 99, at etomidate concentrations of 2-4 mg.L -1, analyzing induction and anesthetic recovery behavior (experiment I), electrocardiogram (experiment II), and opercular movement (experiment III). Fish exposed to high concentrations of etomidate reached the stage of general anesthesia faster, however, the recovery time was longer, characterizing a dose-dependent relationship. Cardiorespiratory analyzes demonstrated a reduction in heart rate (69.19%) and respiratory rate (40.70%) depending on the concentration of etomidate used during anesthetic induction. During the recovery period, there was cardiorespiratory reversibility to normality. Therefore, etomidate proved to be safe as an anesthetic agent for this species at concentrations of 2 to 3 mg.L -1 for short-term anesthesia, but at higher doses the animals showed slow reversibility of anesthesia in a gradual manner and without excitability. The hemodynamic effect due to the rapid decrease in heart rate includes a negative factor of using higher concentrations of etomidate for Colossome macropomum anesthesia.

The odyssey of the TR(i)P journey to the cellular membrane.

Ion channels are integral membrane proteins mediating ion flow in response to changes in their environment. Among the different types of ion channels reported to date, the super-family of TRP channels stands out since its members have been linked to many pathophysiological processes. The family comprises 6 subfamilies and 28 members in mammals, which are widely distributed throughout most tissues and organs and have an important role in several aspects of cellular physiology. It has been evidenced that abnormal expression, post-translational modifications, and channel trafficking are associated with several pathologies, such as cancer, cardiovascular disease, diabetes, and brain disorders, among others. In this review, we present an updated summary of the mechanisms involved in the subcellular trafficking of TRP channels, with a special emphasis on whether different post-translational modifications and naturally occurring mutagenesis affect both expression and trafficking. Additionally, we describe how such changes have been associated with the development and progress of diverse pathologies associated with the gain or loss of functional phenotypes. The study of these processes will not only contribute to a better understanding the role of TRP channels in the different tissues but will also present novel possible therapeutic targets in diseases where their activity is dysregulated.

Perlin noise generation of physiologically realistic cardiac fibrosis.

Fibrosis, a pathological increase in extracellular matrix proteins, is a significant health issue that hinders the function of many organs in the body, in some cases fatally. In the heart, fibrosis impacts on electrical propagation in a complex and poorly predictable fashion, potentially serving as a substrate for dangerous arrhythmias. Individual risk depends on the spatial manifestation of fibrotic tissue, and learning the spatial arrangement on the fine scale in order to predict these impacts still relies upon invasive ex vivo procedures. As a result, the effects of spatial variability on the symptomatic impact of cardiac fibrosis remain poorly understood. In this work, we address the issue of availability of such imaging data via a computational methodology for generating new realisations of cardiac fibrosis microstructure. Using the Perlin noise technique from computer graphics, together with an automated calibration process that requires only a single training image, we demonstrate successful capture of collagen texturing in four types of fibrosis microstructure observed in histological sections. We then use this generator to quantitatively analyse the conductive properties of these different types of cardiac fibrosis, as well as produce three-dimensional realisations of histologically-observed patterning. Owing to the generator's flexibility and automated calibration process, we also anticipate that it might be useful in producing additional realisations of other physiological structures.

Morphographic Changes in the Electrocardiogram of Colossoma macropomum Caused by Exposure to Manganese.

Manganese (Mn2+) is an abundant chemical element in the earth's crust and is present in soil, water, and industrial environments, including mining, welding, and battery manufacturing. Manganese (Mn) is an essential metal needed as a cofactor for many enzymes to maintain proper biological functions. Excessive exposure to Mn in high doses can result in a condition known as manganism, which results in disorders of the neurological, cardiac, and pulmonary systems. The aim of this study was to assess cardiac susceptibility to manganese intoxication in Colossoma macropomum subjected to a fixed concentration of 4 mg/mL for a period of up to 96 h. This study used 45 Tambaquis (30.38 ± 3.5 g) divided into five groups of 9 animals/treatment. The treated groups were exposed to the manganese concentration for a period of 24, 48, 72, and 96 h, after which the animals' ECGs were recorded, showing heart rate, R-R interval, P-Q interval, QRS complex duration and S-T interval. The results showed that cardiac activity decreased as the contact time increased, with an increase in the P-Q and S-T intervals. This indicates that the breakdown of circulatory homeostasis in these animals was caused by contact time with manganese.

Effects of Intravenously Administered Plasma from Exercise-Trained Donors on Microglia and Cytokines in a Transgenic Rat Model of Alzheimer's Disease.

Background: Microglia and inflammation play a significant role in Alzheimer's disease (AD). Physical exercise and peripheral signals can influence microglial activity in the brain. Modulating the inflammatory response in the brain may provide therapeutic approaches for AD. Objective: To assess the effects of intravenously administered blood plasma from exercise-trained donor rats on cognitive function, microglia, and cytokine levels in an AD rat model at two different pathological stages; an early pre-plaque stage and a later stage closer to the emergence of extracellular plaques. Methods: Male transgenic McGill-R-Thy1-APP rats aged 2 and 5 months received 14 injections over 6 weeks: 1) plasma from exercise-trained rats (ExPlas), 2) plasma from sedentary rats (SedPlas), or 3) saline. Cognitive function was evaluated in a novel object recognition task. Microglia count and morphology were analyzed in cornu ammonis, dentate gyrus, entorhinal cortex, and subiculum. Amyloid plaque number and size were assessed in the rats with the later treatment start. A multiplex assay was used to measure 23 cytokines in cornu ammonis. Results: In rats treated from 2 months of age, ExPlas and SedPlas increased number and length of microglial branches in cornu ammonis and dentate gyrus compared to saline. Only ExPlas-treated rats exhibited similar changes in subiculum, while entorhinal cortex showed no differences across treatments. Microglia count remained unaffected. In rats treated from 5 months of age, there were no significant differences in microglia count or morphology or the number or size of amyloid plaques in any brain region. Compared to both other treatments in early pre-plaque stage rats, SedPlas increased TNF-α levels. ExPlas upregulated GM-CSF, IL-18, and VEGF, while SedPlas increased IL-10 compared to saline. In later-stage rats, ExPlas upregulated IL-17, and SedPlas upregulated TNF-α compared to saline. There were no effects of treatments on recognition memory. Conclusions: Intravenous injections of blood plasma from exercise-trained and sedentary donors differentially modulated microglial morphology and cytokine levels in the AD rat model at an early pre-plaque stage of pathology. Exercised plasma may reduce proinflammatory TNF-α signaling and promote microglial responses to early Aß accumulation but the lack of treatment effects in the later-stage rats emphasizes the potential importance of treatment timing.

Influence of Silica Modulus on the Activation of Amorphous Wollastonitic Hydraulic Binders with Different Alumina Content: Study of Hydration Reaction and Paste Performance.

This study investigates how different sodium silicate SiO2/Na2O MS ratios (0.75, 0.9, and 1.2) affect the hydration behavior of amorphous wollastonitic hydraulic (AWH) binders containing various amounts of Al2O3 content (4, 7, 10, and 12%wt). The effects of and interaction between the MS ratio of the activator and the Al2O3 content of the sample on the hydration reaction and paste performance were investigated. The reaction was followed by calorimetry, and the pastes' compressive strength performances were tested at different curing times (2, 7, and 28 days). The hydrated pastes were characterized by FTIR, thermogravimetry analysis, and X-ray diffraction. The calorimetric results show that a higher Al2O3 cContent and a higher MS ratio result in a longer induction period. In terms of paste performance, an increase of the Al2O3 coupled with an activation with a 1.2 MS ratio results in a lower compressive strength after 28 days of hydration; the results range from 76 to 52 MPa. A decrease of the MS ratio to 0.9 allowed the obtention of a narrower range of results, from 76 to 69 MPa. Even though a decrease of the MS ratio to 0.75 led to higher hydration kinetics and high compressive strength results at early ages, at 28 days of curing, a decrease in compressive strength was observed. This may be a consequence of the fast kinetic of the mixture, since the rapid growth of hydration products may inhibit the dissolution at later ages and increase the porosity of the paste. Moreover, the high Al intake in the hydration product, facilitated by the high sodium content of the activator, promotes the formation of a higher number of calcium aluminate silicate hydrate structures (C-A-S-H) to the detriment of calcium silicate hydrate structures (C-S-H), decreasing the compressive strength of the samples. The TGA results indicate that the samples hydrated with the MS075 solution resulted in a higher number of hydrated products at early ages, while the samples hydrated with the MS09 and MS1.2 solutions exhibit a steady increase with curing time. Hence, an equilibrium in the hydration kinetic promoted by Si saturation-undersaturation appears to be fundamental in this system, which is influenced by both the MS ratio and the Al(OH)4- content in solution. The results of this study suggest that for this type of binder, optimal performance can be achieved by decreasing the MS ratio to 0.9. This composition allows for a controlled kinetic and overall higher compressive strength results in pastes produced with this AWH precursor.

Recording of hippocampal activity on the effect of convulsant doses of caffeine.

Seizures occur when there is a hyper-excitation of the outer layer of the brain, with subsequent excessive synchrony in a group of neurons. According to the World Health Organization (WHO), an estimated 50 million people are affected by this disease, a third of whom are resistant to the treatments available on the market. Caffeine (1,3,7-trimethylxanthine), which belongs to the purine alkaloid family, is the most widely consumed psychoactive drug in the world. It is ingested by people through drinks containing this substance, such as coffee, and as an adjuvant in analgesic therapy with non-steroidal antiflammatory drugs. The present study evaluated the electrocorticographic changes observed in the hippocampus of Wistar rats subjected to acute doses of caffeine (150 mg/kg i.p), which represents a toxic dose of caffeine corresponding to an estimated acute intake of more than 12 cups of coffee to record its convulsant activity. Our results showed, for the first time, that the administration of high doses of caffeine (150 mg/kg i.p.) in rats caused an increase in the spectral distribution of power in all frequency bands and suggested the appearance of periods of ictal and interictal peaks in the electrocorticogram (ECog). We have also shown that the anticonvulsants phenytoin, diazepam and phenobarbital have a satisfactory response when associated with caffeine.

Impact of transsexualizing process centers on self-medication of transgender individuals.

OBJECTIVE: The transgender population in Brazil faces marginalization and difficulties in accessing education and health, leading many individuals to self-medicate. This study aimed to evaluate the impact of the implementation of Specialized Centers in the Transsexualizing Process (SCTP) on the use of cross-sex hormone therapy (CSHT) without medical prescription, as well as the level of education and mental health profile of these individuals. METHODS: This is a cross-sectional study with data from physical and electronic medical records between September 2017 and February 2023 regarding the use of CSHT before and after the implementation of two SCTP in the state of Bahia, Brazil, in addition to data on education level, previous diagnosis of anxiety and depression of patients. RESULTS: A total of 219 participants, 127 transgender men (TM) and 92 transgender women and travestis (TrTW), were assessed. A significant reduction in the prevalence of self-medication was observed in both TrTW (92.98% before and 51.43% after, p<0.001), and TM (47.17% before and 25.67% after, p = 0.010) with the implementation of SCTP. Transgender individuals who used CSHT before accessing the service were found to have a lower prevalence of depression. Self-medication was not significantly associated with education or anxiety in our sample. CONCLUSION: The results indicate the need for the expansion of SCTP, as they were associated with lower rates of self-medication in the transgender population.

Identification of methodological issues regarding direct impact indicators of COVID-19: a rapid scoping review on morbidity, severity and mortality.

BACKGROUND: During the first epidemic wave, COVID-19 surveillance focused on quantifying the magnitude and the escalation of a growing global health crisis. The scientific community first assessed risk through basic indicators, such as the number of cases or rates of new cases and deaths, and later began using other direct impact indicators to conduct more detailed analyses. We aimed at synthesizing the scientific community's contribution to assessing the direct impact of the COVID-19 pandemic on population health through indicators reported in research papers. METHODS: We conducted a rapid scoping review to identify and describe health indicators included in articles published between January 2020 and June 2021, using one strategy to search PubMed, EMBASE and WHO COVID-19 databases. Sixteen experts from European public health institutions screened papers and retrieved indicator characteristics. We also asked in an online survey how the health indicators were added to and used in policy documents in Europe. RESULTS: After reviewing 3891 records, we selected a final sample of 67 articles and 233 indicators. We identified 52 (22.3%) morbidity indicators from 33 articles, 105 severity indicators (45.1%, 27 articles) and 68 mortality indicators (29.2%, 51). Respondents from 22 countries completed 31 questionnaires, and the majority reported morbidity indicators (29, 93.5%), followed by mortality indicators (26, 83.9%). CONCLUSIONS: The indicators collated here might be useful to assess the impact of future pandemics. Therefore, their measurement should be standardized to allow for comparisons between settings, countries and different populations.

Antimicrobial Potential of Chitosan Films Incorporated with Alcoholic Extract from Mimosa tenuiflora Leaves.

Antimicrobial films were prepared with chitosan containing the methanolic extract of M. tenuiflora leaves (FECT20%, FECT30%, and FECT40%), and their antimicrobial activities were evaluated by agar diffusion. The films were characterized by IR spectroscopy, scanning electron microscopy (SEM) and TG/DTG curves. TG/DTG curves showed thermal stability of chitosan-extract films up to 166 ºC. Micrographs of chitosan-extract films revealed an increase in porosity with the addition of extract. The FECT40% film showed inhibition zone diameters (IZ) against Micrococcus luteus, Staphylococcus aureus, Bacillus subtilis, and B. cereus, ranging from 1.0 ± 0.02 to 0.72 ± 0.09 cm. Only FECT30% and FECT40% inhibited the P. aeruginosa with IZs of 0.68 ± 0.02 and 0.77 ± 0.06 cm, respectively. In turn, the extract showed inhibition against B. subtilis and B. cereus, with IZs values of 0.92 ± 0.2 cm and 0.72 ± 0.05 cm, respectively. Additionally, the crude extract presented antioxidant potential with inhibition percentages of 32.74% ± 0.90 for ABTS and 27.04% ± 1.36 for DPPH. The antimicrobial and antioxidant activities of the crude extract, as well as the antimicrobial property of chitosan-extract films, suggests the potential of these biopolymers for the development of wound healing bandages and new food packaging alternatives.

"You get out of the house, you talk to each other, you laugh And that's fantastic" - a qualitative study about older people's perceptions of social prescribing in mainland Portugal.

BACKGROUND: Social prescribing (SP) is a non-clinical approach, most commonly based in healthcare units, that aims to address non-medical health-related social needs by connecting individuals with community-based services. This qualitative study explores the perception of Portuguese older adults regarding the benefits of SP and their willingness to participate in SP initiatives. METHODS: Three face-to-face focus group sessions were conducted with 23 participants in different cities in Portugal. Open and semi-open questions were used to guide the discussions and thematic analysis was used to analyze the data. RESULTS: The participants recognized the potential benefits of SP for older adults, including diversifying leisure activities, improving mental health, and complementing existing support systems. They highlighted the need for external support, usually in the form of link workers, to facilitate personalized referrals and consider individual characteristics and preferences. While some participants expressed reluctance to engage in SP due to their existing busy schedules and a perceived sense of imposition, others showed openness to having new experiences and recognized the potential value of SP in promoting activity. Barriers to participation, including resistance to change, mobility issues, and family responsibilities, were identified. CONCLUSIONS: The study emphasizes the importance of a person-centered and co-designed approach to SP, involving older adults in the planning and implementation of interventions. The findings provide valuable insights for the development of SP programs tailored to the unique needs and aspirations of older adults in Portugal, ultimately promoting active and healthy aging. Future research should consider the perspectives of family doctors and include a broader representation of older adults from diverse geographic areas.

Bridging the gap between models based on ordinary, delayed, and fractional differentials equations through integral kernels.

Evolution equations with convolution-type integral operators have a history of study, yet a gap exists in the literature regarding the link between certain convolution kernels and new models, including delayed and fractional differential equations. We demonstrate, starting from the logistic model structure, that classical, delayed, and fractional models are special cases of a framework using a gamma Mittag-Leffler memory kernel. We discuss and classify different types of this general kernel, analyze the asymptotic behavior of the general model, and provide numerical simulations. A detailed classification of the memory kernels is presented through parameter analysis. The fractional models we constructed possess distinctive features as they maintain dimensional balance and explicitly relate fractional orders to past data points. Additionally, we illustrate how our models can reproduce the dynamics of COVID-19 infections in Australia, Brazil, and Peru. Our research expands mathematical modeling by presenting a unified framework that facilitates the incorporation of historical data through the utilization of integro-differential equations, fractional or delayed differential equations, as well as classical systems of ordinary differential equations.

Analysis of the fight against the COVID-19 pandemic in long-term care facilities in the pre-vaccination period.

INTRODUCTION: The COVID-19 pandemic has disproportionately affected individuals residing in Long-Term Care Facilities (LTCFs), necessitating tailored strategies to manage outbreaks. This study examines the outcomes of the ILPI BH project, a collaborative effort between the Municipal Health Department and the Hospital das Clínicas of the Federal University of Minas Gerais, designed to mitigate COVID-19 spread within LTCFs. METHODS: Prospective cohort of secondary data: 1,794 old residents in 99 long-term care facilities of Belo Horizonte, Brazil, were followed from May 2020 to January 2021. The study analyzed the prevention strategies, residents' clinical data, and the characteristics of the long-term care facilities, correlating these variables with the number of infections, hospitalizations, and deaths from COVID-19. It checked absolute numbers and rates of incidence, hospitalization, mortality, and lethality. RESULTS: There have been 58 COVID-19 outbreaks in long-term care facilities. There were 399 cases among residents, 96 hospitalizations for COVID-19 and 48 deaths from COVID-19 (2.7 % of the cohort), with a case fatality rate of 12 %. After multivariate analysis, the intrinsic variables to residents associated with higher mortality risk were higher degree of frailty (OR=1.08; p = 0.004) and the fact of living in a long-term care facility with a considerable proportion of residents' coverage by health plans (OR = 1.01; p = 0.028). Early geriatric follow-up showed an association with a reduction in the number of hospitalizations due to COVID-19. CONCLUSION: The correct classification of the degree of frailty of institutionalized older people seems to have been relevant for predicting mortality from COVID-19. The extensive assistance by private health plans, contrary to what is supposed, did not result in better health protection. Early geriatric follow-up was beneficial and may be an attractive strategy in the face of health emergencies that affect long-term care facilities to reduce hospital admissions.

The role of satellite DNAs in the chromosomal rearrangements and the evolution of the rare XY1Y2 sex system in Harttia (Siluriformes: Loricariidae).

The underlying processes behind the formation, evolution, and long-term maintenance of multiple sex chromosomes have been largely neglected. Among vertebrates, fishes represent the group with the highest diversity of multiple sex chromosome systems and, with six instances, the Neotropical fish genus Harttia stands out by presenting the most remarkable diversity. However, although the origin mechanism of their sex chromosome systems is well discussed, little is known about the importance of some repetitive DNA classes in the differentiation of multiple systems. In this work, by employing a combination of cytogenetic and genomic procedures, we evaluated the satellite DNA composition of H. carvalhoi with a focus on their role in the evolution, structure, and differentiation process of the rare XY1Y2 multiple-sex chromosome system. The genome of H. carvalhoi contains a total of 28 satellite DNA families, with the A + T content ranging between 38.1% and 68.1% and the predominant presence of long satellites. The in situ hybridization experiments detected 15 satellite DNAs with positive hybridization signals mainly on centromeric and pericentromeric regions of almost all chromosomes or clustered on a few pairs. Five of them presented clusters on X, Y1, and/or Y2 sex chromosomes which were therefore selected for comparative hybridization in the other three congeneric species. We found several conserved satellites accumulated on sex chromosomes and also in regions that were involved in chromosomal rearrangements. Our results provide a new contribution of satellitome studies in multiple sex chromosome systems in fishes and represent the first satellitome study for a Siluriformes species.

Evolution of bird sex chromosomes: a cytogenomic approach in Palaeognathae species.

BACKGROUND: Different patterns of sex chromosome differentiation are seen in Palaeognathae birds, a lineage that includes the ratites (Struthioniformes, Rheiformes, Apterygiformes, Casuariiformes, and the sister group Tinamiformes). While some Tinamiform species have well-differentiated W chromosomes, both Z and W of all the flightless ratites are still morphologically undifferentiated. Here, we conducted a comprehensive analysis of the ZW differentiation in birds using a combination of cytogenetic, genomic, and bioinformatic approaches. The whole set of satDNAs from the emu (Dromaius novaehollandiae) was described and characterized. Furthermore, we examined the in situ locations of these satDNAs alongside several microsatellite repeats and carried out Comparative Genomic Hybridizations in two related species: the greater rhea (Rhea americana) and the tataupa tinamou (Crypturellus tataupa). RESULTS: From the 24 satDNA families identified (which represent the greatest diversity of satDNAs ever uncovered in any bird species), only three of them were found to accumulate on the emu's sex chromosomes, with no discernible accumulation observed on the W chromosome. The W chromosomes of both the greater rhea and the emu did not exhibit a significant buildup of either C-positive heterochromatin or repetitive DNAs, indicating their large undifferentiation both at morphological and molecular levels. In contrast, the tataupa tinamou has a highly differentiated W chromosome that accumulates several DNA repeats. CONCLUSION: The findings provide new information on the architecture of the avian genome and an inside look at the starting points of sex chromosome differentiation in birds.