MDFF_NM: Improved Molecular Dynamics Flexible Fitting into Cryo-EM Density Maps with a Multireplica Normal Mode-Based Search.

Molecular Dynamics Flexible Fitting (MDFF) is a widely used tool to refine high-resolution structures into cryo-EM density maps. Despite many successful applications, MDFF is still limited by its high computational cost, overfitting, accuracy, and performance issues due to entrapment within wrong local minima. Modern ensemble-based MDFF tools have generated promising results in the past decade. In line with these studies, we present MDFF_NM, a stochastic hybrid flexible fitting algorithm combining Normal Mode Analysis (NMA) and simulation-based flexible fitting. Initial tests reveal that, besides accelerating the fitting process, MDFF_NM increases the diversity of fitting routes leading to the target, uncovering ensembles of conformations in closer agreement with experimental data. The potential integration of MDFF_NM with other existing methods and integrative modeling pipelines is also discussed.

Cholesterol transfer to high-density lipoprotein in obesity and the effects of weight loss after bariatric surgery.

Obesity increases serum triglycerides and decreases high-density lipoprotein cholesterol (HDL-C). The objective is to explore some functions of HDL, cholesterol transfers and antioxidant, in subjects with grade I (G1-OB) and III (G3-OB) obesity and effects of bariatric surgery on G3-OB. Fifteen G3-OB patients (43 ± 6 years, BMI 49 ± 3 kg/m2) were studied before and 1 year after bariatric surgery; 15 G1-OB (32 ± 2 years, 32 ± 2 kg/m2) and 15 normal weight (NW) (38 ± 6 years, 22 ± 1 kg/m2) were also studied. HDL diameter, cholesterol transfer to HDL and antioxidant capacity of HDL were determined. G3-OB had higher triglycerides and lower HDL-C; G1-OB had higher triglycerides than NW but HDL-C was equal. Compared to NW, HDL size was smaller in G3-OB but equal in G1-OB. One year after bariatric surgery, BMI and triglycerides of G3-OB decreased (p < .0001 and p = .0012, respectively) and HDL-C increased (p < .0001), equalling of NW group. Antioxidant capacity and cholesterol transfers were not different in groups and were unchanged 1 year after bariatric surgery in G3-OB. HDL antioxidant capacity and transfer of cholesterol to HDL were not defective in obesity despite HDL-C reduction and smaller HDL size. In addition, pronounced weight loss by bariatric surgery did not change those protective functions.

Microbial successional pattern along a glacier retreat gradient from Byers Peninsula, Maritime Antarctica.

The retreat of glaciers in Antarctica has increased in the last decades due to global climate change, influencing vegetation expansion, and soil physico-chemical and biological attributes. However, little is known about soil microbiology diversity in these periglacial landscapes. This study characterized and compared bacterial and fungal diversity using metabarcoding of soil samples from the Byers Peninsula, Maritime Antarctica. We identified bacterial and fungal communities by amplification of bacterial 16 S rRNA region V3-V4 and fungal internal transcribed spacer 1 (ITS1). We also applied 14C dating on soil organic matter (SOM) from six profiles. Physico-chemical analyses and attributes associated with SOM were evaluated. A total of 14,048 bacterial ASVs were obtained, and almost all samples had 50% of their sequences assigned to Actinobacteriota and Proteobacteria. Regarding the fungal community, Mortierellomycota, Ascomycota and Basidiomycota were the main phyla from 1619 ASVs. We found that soil age was more relevant than the distance from the glacier, with the oldest soil profile (late Holocene soil profile) hosting the highest bacterial and fungal diversity. The microbial indices of the fungal community were correlated with nutrient availability, soil reactivity and SOM composition, whereas the bacterial community was not correlated with any soil attribute. The bacterial diversity, richness, and evenness varied according to presence of permafrost and moisture regime. The fungal community richness in the surface horizon was not related to altitude, permafrost, or moisture regime. The soil moisture regime was crucial for the structure, high diversity and richness of the microbial community, specially to the bacterial community. Further studies should examine the relationship between microbial communities and environmental factors to better predict changes in this terrestrial ecosystem.

Current Challenges and Perspectives in Breast Cancer in Elderly Women: The Senologic International Society (SIS) Survey.

Objective: Mammographic screening and management of breast cancer (BC) in elderly women are controversial and continue to be an important health problem. To investigate, through members of the Senologic International Society (SIS), the current global practices in BC in elderly women, highlighting topics of debate and suggesting perspectives. Materials and Methods: The questionnaire was sent to the SIS network and included 55 questions on definitions of an elderly woman, BC epidemiology, screening, clinical and pathological characteristics, therapeutic management in elderly women, onco-geriatric assessment and perspectives. Results: Twenty-eight respondents from 21 countries and six continents, representing a population of 2.86 billion, completed and submitted the survey. Most respondents considered women 70 years and older to be elderly. In most countries, BC was often diagnosed at an advanced stage compared to younger women, and age-related mortality was high. For this reason, participants recommended that personalized screening be continued in elderly women with a long life expectancy.In addition, this survey highlighted that geriatric frailty assessment tools and comprehensive geriatric evaluations needed to be used more and should be developed to avoid undertreatment. Similarly, multidisciplinary meetings dedicated to elderly women with BC should be encouraged to avoid under- and over-treatment and to increase their participation in clinical trials. Conclusion: Due to increased life expectancy, BC in elderly women will become a more important field in public health. Therefore, screening, personalized treatment, and comprehensive geriatric assessment should be the cornerstones of future practice to avoid the current excess of age-related mortality. This survey described, through members of the SIS, a global picture of current international practices in BC in elderly women.

Speciation Underpinned by Unexpected Molecular Diversity in the Mycorrhizal Fungal Genus Pisolithus.

The mutualistic ectomycorrhizal (ECM) fungal genus Pisolithus comprises 19 species defined to date which colonize the roots of >50 hosts worldwide suggesting that substantial genomic and functional evolution occurred during speciation. To better understand this intra-genus variation, we undertook a comparative multi-omic study of nine Pisolithus species sampled from North America, South America, Asia, and Australasia. We found that there was a small core set of genes common to all species (13%), and that these genes were more likely to be significantly regulated during symbiosis with a host than accessory or species-specific genes. Thus, the genetic "toolbox" foundational to the symbiotic lifestyle in this genus is small. Transposable elements were located significantly closer to gene classes including effector-like small secreted proteins (SSPs). Poorly conserved SSPs were more likely to be induced by symbiosis, suggesting that they may be a class of protein that tune host specificity. The Pisolithus gene repertoire is characterized by divergent CAZyme profiles when compared with other fungi, both symbiotic and saprotrophic. This was driven by differences in enzymes associated with symbiotic sugar processing, although metabolomic analysis suggest that neither copy number nor expression of these genes is sufficient to predict sugar capture from a host plant or its metabolism in fungal hyphae. Our results demonstrate that intra-genus genomic and functional diversity within ECM fungi is greater than previously thought, underlining the importance of continued comparative studies within the fungal tree of life to refine our focus on pathways and evolutionary processes foundational to this symbiotic lifestyle.

MDexciteR: Enhanced Sampling Molecular Dynamics by Excited Normal Modes or Principal Components Obtained from Experiments.

Molecular dynamics with excited normal modes (MDeNM) is an enhanced sampling method for exploring conformational changes in proteins with minimal biases. The excitation corresponds to injecting kinetic energy along normal modes describing intrinsic collective motions. Herein, we developed a new automated open-source implementation, MDexciteR (https://github.com/mcosta27/MDexciteR), enabling the integration of MDeNM with two commonly used simulation programs with GPU support. Second, we generalized the method to include the excitation of principal components calculated from experimental ensembles. Finally, we evaluated whether the use of coarse-grained normal modes calculated with elastic network representations preserved the performance and accuracy of the method. The advantages and limitations of these new approaches are discussed based on results obtained for three different protein test cases: two globular and a protein/membrane system.

Fatores associados ao baixo apgar em recém-nascidos angolanos / Factors associated with low apgar in angolan newborn / Factores asociados con apgar bajo en recién nacidos angolanos

Objetivo:avaliar os fatores associados ao baixo Apgar em recém-nascidos de Angola. Método:estudo analíticoe transversal, quali-quantitativo, em umHospital Geral de Luanda, Angola, entre março e maio de 2021. Realizou-se entrevistas em sala de observação e consulta aos prontuários das parturientes. Os dados foram analisados pelo teste qui-quadrado (X2) e regressão logística. Resultados:prevaleceu parturientes entre 19-35 anos (70,0%), 7º-9º ano (57,5%), multíparas (75%), multigestas (75,0%), sem histórico de aborto (72,5%), idade gestacional de 40 semanas (60,0%), usuárias de bebidas alcoólicas (77,5%), baixa frequência de consultas pré-natais (52,5%), com parto natural (82,5%) e recém-nascidos com peso normal (52,5%). Mulheres de região periurbana [OR:6,85 (95% CI:0.65-71,2), p=0,108] e rural [OR:4,47 (95% CI:0.47-48,4), p=0,184] apresentaram maior chance de terem recém-nascidos com baixo Apgar, assim como as usuárias de álcool [OR:3,28 (95% CI:0,58-18,3), p=0,176] e recém-nascidos que nasceram com peso normal [OR:1,75 (95% CI:0,49­6,22), p=0,387]. Não houve associação estatística entre os dados sociodemográficos e maternos. Conclusão:a faixa etária, local de residência, consumo de álcool materno e peso do recém-nascido podem implicar em baixo Apgar.

Objective: to evaluate the factors associated with low Apgar in newborns in Angola. Method:analytical and cross-sectional, quali-quantitative study, in a General Hospital in Luanda, Angola, between March and May 2021. Interviews were carried out in an observation room and consultation of the parturients' medical records. Data were analyzed using the chi-square test (X2) and logistic regression.Results: pregnant women aged 19-35 years (70.0%), 7th-9th year(57.5%), multiparous (75%), multiparous (75.0%), without a history of abortion (72.5%), prevailed. gestational age of 40 weeks (60.0%), users of alcoholic beverages (77.5%), low frequency of prenatal consultations (52.5%), with natural childbirth (82.5%) and newborns with normal weight (52.5%). Women from peri-urban regions [OR:6.85 (95% CI:0.65-71.2), p=0.108] and rural [OR:4.47 (95% CI:0.47-48.4), p=0.184] were more likely to have low Apgar newborns, as well as alcohol users [OR:3.28 (95% CI:0.58-18.3), p=0.176] and newborns who were born with normal [OR:1.75 (95% CI:0.49­6.22), p=0.387]. There was no statistical association between sociodemographic and maternal data.Conclusion: age group, place of residence, maternal alcohol consumption and newborn weight may imply low Apgar.

Objetivo: evaluar los factores asociados al Apgar bajo en recién nacidos en Angola.Método: estudio analítico y transversal, cuali-cuantitativo, en un Hospital General de Luanda, Angola, entre marzo y mayo de 2021. Se realizaron entrevistas en sala de observación y consulta de las historias clínicas de las parturientas. Los datos se analizaron mediante la prueba de chi-cuadrado (X2) y regresión logística. Resultados: gestantes de 19 a 35 años (70,0%), de 7° a 9° año (57,5%), multíparas (75%), multíparas (75,0%), sin antecedente de aborto (72,5%), predominó la edad gestacional de 40 semanas (60,0%), usuarias de bebidas alcohólicas (77,5%), baja frecuencia de consultas prenatales (52,5%), con parto natural (82,5%) y recién nacidos con normopeso (52,5%). Las mujeres de regiones periurbanas [OR:6,85 (IC 95%:0,65-71,2), p=0,108] y rurales [OR:4,47 (IC 95%:0,47-48,4), p=0,184] tenían más probabilidades de tener bajo Recién nacidos Apgar, así como consumidores de alcohol [OR:3,28 (IC 95%:0,58-18,3), p=0,176] y recién nacidos que nacieron con normalidad [OR:1,75 (IC 95%:0,49-6,22), p=0,387]. No hubo asociación estadística entre datos sociodemográficos y maternos. Conclusión: el grupo de edad, el lugar de residencia, el consumo materno de alcohol y el peso del recién nacido pueden implicar un Apgar bajo.

Possible Amazonian contribution to Sargassum enhancement on the Amazon Continental Shelf.

The Amazon Continental Shelf (ACS) has a coastline of ∼1000 km and is situated in a humid equatorial region with two distinct seasons, wet and dry, and two transitional climatic periods. A total of eight oceanographic cruises were conducted to investigate the dynamics of the inorganic nutrients dissolved in the surface layer of the water column of the ACS and their associations with Sargassum blooms. An excess of nitrogen-N* (NH4+ = 0.01-9.30 µmol l-1) was verified through the salinity gradient from the continent to the ACS, mainly during the period of maximum discharge of the Amazon and Tocantins-Pará rivers. The highest NH4+ concentrations coincided with the occurrence of macrophyte (Sargassum sp.) blooms in the mesohaline and oceanic regions. During this period the high values of NH4+ accompany the low values of Sea Surface Salinity (SSS), indicating the advection of the Amazonian plume towards the Caribbean Sea. In the Sargassum belts we observed a N:P ratio = 60:1 during wet period, while outside this region, the N:P ratio was 34:1. According to DIN vs. AOU ratio, we observed that heterotrophic processes prevail over productive processes, mainly in the mesohaline and low salinity regions. Nitrogen concentrations from runoff, mainly from hydrographic basins, showed significant increases in the last decade, mainly due to anthropogenic factors such as agriculture, deforestation, livestock, urban sewage (domestic and industrial), and demographic growth of the population in the Tocantins-Pará Basin. Additionally, associations of diatoms and cyanobacteria provide more nitrogen in the mesohaline and oceanic regions that nourishes Sargassum blooms. Seasonal comparisons (October and April) of Sargassum belts with other studies, indicated that currents play a fundamental role in the transport of these macrophytes from the east edge (Africa) to the west edge (Brazil and French Guiana) towards the Caribbean Sea in the tropical Atlantic.

The Senologic International Society Survey on Ductal Carcinoma In Situ: Present and Future.

Objective: Therapeutic management of ductal carcinoma in situ (DCIS) is heterogeneous among countries worldwide, and some treatment indications are still controversial. To investigate DCIS management in different countries; identify both consensual practices and controversial topics; and survey opinions about the future management of DCIS. Materials and Methods: The Senologic International Society network members participated to an online survey using a questionnaire, between November 2021 and February 2022. Results: Twenty-two responses from 20 different countries showed that organized breast cancer screening programs were present for 87% participants, and DCIS cases represented 13.7% of all breast cancers. Most participants used the grade classification (100%), the morphological classification (78%) and performed immunohistochemistry assays (73%). In case of conservative treatment, the mean re-excision rate was 10.3% and clear margins of mean 2.5 mm were considered healthy. Radical mastectomy rate was 35.5% with a breast reconstruction rate of 53%. Tumor bed boost indications were heterogeneous, and 73% of participants indicated hormone therapy for hormone-positive DCIS. Surgery and radiotherapy omission for some low-risk DCIS were considered by 73% of participants. Multigene assays were used by 43% of participants. Concerning future changes in DCIS management, participants mostly answered surgical de-escalation (48%), radiotherapy de-escalation (35) and/or active surveillance for some cases (22%). Conclusion: This survey provided an overview of the current practices of DCIS management worldwide. It showed that some areas are rather consensual: incidence increases over time, treatment in young women, pathological classifications, definition of healthy margins, the skin-sparing mastectomy and immediate breast reconstruction. However, some topics are still debated and result in heterogeneous practices, such as evolution in the age of diagnosis, the benefit of de-escalation in low-risk DCIS among elderly women, indications for hormone therapy, radiotherapy omission, or multigene assays. Further evidence is needed to reach consensus on these points, and innovative approaches are still under evaluation in clinical trials. The International Senologic Society, by its members, encourages precision medicine and personalized treatments for DCIS, to avoid overtreatment and overdiagnosis, and provide better healthcare to women with DCIS.

The C-Terminal Acidic Tail Modulates the Anticancer Properties of HMGB1.

Energy metabolism reprogramming was recently listed as a hallmark of cancer. In this process, the switch from pyruvate kinase isoenzyme type M1 to pyruvate kinase isoenzyme type M2 (PKM2) is believed to play a crucial role. Interestingly, the activity of the active form of PKM2 can efficiently be inhibited by the high-mobility group box 1 (HMGB1) protein, leading to a rapid blockage of glucose-dependent aerobic respiration and cancer cell death. HMGB1 is a member of the HMG protein family. It contains two DNA-binding HMG-box domains and an acidic C-terminal tail capable of positively or negatively modulating its biological properties. In this work, we report that the deletion of the C-terminal tail of HMGB1 increases its activity towards a large panel of cancer cells without affecting the viability of normal immortalized fibroblasts. Moreover, in silico analysis suggests that the truncated form of HMGB1 retains the capacity of the full-length protein to interact with PKM2. However, based on the capacity of the cells to circumvent oxidative phosphorylation inhibition, we were able to identify either a cytotoxic or cytostatic effect of the proteins. Together, our study provides new insights in the characterization of the anticancer activity of HMGB1.

Sampling of Protein Conformational Space Using Hybrid Simulations: A Critical Assessment of Recent Methods.

Recent years have seen several hybrid simulation methods for exploring the conformational space of proteins and their complexes or assemblies. These methods often combine fast analytical approaches with computationally expensive full atomic molecular dynamics (MD) simulations with the goal of rapidly sampling large and cooperative conformational changes at full atomic resolution. We present here a systematic comparison of the utility and limits of four such hybrid methods that have been introduced in recent years: MD with excited normal modes (MDeNM), collective modes-driven MD (CoMD), and elastic network model (ENM)-based generation, clustering, and relaxation of conformations (ClustENM) as well as its updated version integrated with MD simulations (ClustENMD). We analyzed the predicted conformational spaces using each of these four hybrid methods, applied to four well-studied proteins, triosephosphate isomerase (TIM), 3-phosphoglycerate kinase (PGK), HIV-1 protease (PR) and HIV-1 reverse transcriptase (RT), which provide extensive ensembles of experimental structures for benchmarking and comparing the methods. We show that a rigorous multi-faceted comparison and multiple metrics are necessary to properly assess the differences between conformational ensembles and provide an optimal protocol for achieving good agreement with experimental data. While all four hybrid methods perform well in general, being especially useful as computationally efficient methods that retain atomic resolution, the systematic analysis of the same systems by these four hybrid methods highlights the strengths and limitations of the methods and provides guidance for parameters and protocols to be adopted in future studies.

Concerted conformational dynamics and water movements in the ghrelin G protein-coupled receptor.

There is increasing support for water molecules playing a role in signal propagation through G protein-coupled receptors (GPCRs). However, exploration of the hydration features of GPCRs is still in its infancy. Here, we combined site-specific labeling with unnatural amino acids to molecular dynamics to delineate how local hydration of the ghrelin receptor growth hormone secretagogue receptor (GHSR) is rearranged upon activation. We found that GHSR is characterized by a specific hydration pattern that is selectively remodeled by pharmacologically distinct ligands and by the lipid environment. This process is directly related to the concerted movements of the transmembrane domains of the receptor. These results demonstrate that the conformational dynamics of GHSR are tightly coupled to the movements of internal water molecules, further enhancing our understanding of the molecular bases of GPCR-mediated signaling.

Investigação dos níveis de ansiedade e depressão em acadêmicos de odontologia de uma Instituição de Ensino Superior / Investigation of anxiety and depression levels in dentistry academics of a Higher Education Institution

A pesquisa teve como objetivo determinar os níveis de ansiedade e depressão dos estudantes de graduação de odontologia em uma instituição de ensino superior. O estudo é de caráter transversal, realizado em 2018 com 263 estudantes de graduação em odontologia utilizando a Escala Hospitalar de Ansiedade e Depressão (EHAD) em forma de questionário com variáveis sociodemográficas para avaliação dos níveis de ansiedade e depressão apresentados por esses discentes. Um total de 74,52% da amostra apresentou sintomas sugestivos de ansiedade e depressão, sendo 53,62% representada por mulheres e apenas 20,09% representado por homens. Apenas 25,48% dos participantes não apresentaram sintomas de ansiedade e depressão. As implicações que os transtornos emocionais causam no desempenho acadêmico precisam de medidas de diagnóstico precoce para evitar a evolução da doença, trabalhando também na difusão de informações visando a busca de meios que garantam uma melhora na saúde mental dos participantes da pesquisa... (AU)

The research aimed to determine the anxiety and depression levels of undergraduate dentistry students at a higher education institution. The cross-sectional study was carried out in 2018 with 263 undergraduate dentistry students using a Hospital Anxiety and Depression Scale (EHAD) in the form of a questionnaire with sociodemographic variables to assess the levels of anxiety and depression due to these students. A total of 74.52% of the sample presented symptoms suggestive of anxiety and depression, with 53.62% represented by women and only 20.09% represented by men. Only 25.48% of participants were not dependent on anxiety and depression. As a result that emotional disorders cause academic performance, early diagnosis measures are needed to prevent the disease from developing, also working on the dissemination of integrated information and the search for ways to guarantee an improvement in the mental health of the research participants... (AU)

New Frontiers for Fairer Breast Cancer Care in a Globalized World.

In early 2020, the book "Breast cancer: Global Quality Care" was published by Oxford University Press. In the year since then, publications, interviews (by ecancer), presentations, webinars, and virtual congress have been organized to disseminate further the main message of the project: "A call for Fairer Breast Cancer Care for all Women in a Globalized World." Special attention is paid to increasing the "value-based healthcare" putting the patient in the center of the care pathway and sharing information on high-quality integrated breast cancer care. Specific recommendations are made considering the local resource facilities. The multidisciplinary breast conference is considered "the jewel in the crown" of the integrated practice unit, connecting multiple specializations and functions concerned with patients with breast cancer. Management and coordination of medical expertise, facilities, and their interfaces are highly recommended. The participation of two world-leading cancer research programs, the CONCORD program and Breast Health Global Initiative, in this project has been particularly important. The project is continuously under review with feedback from the faculty. The future plan is to arrive at an openaccess publication that is freely available to all interested people. This project is designed to help ease the burden and suffering of women with breast cancer across the globe.

Breast Cancer Management During the COVID-19 Pandemic: The Senologic International Society Survey.

OBJECTIVE: In early 2020, the spread of coronavirus disease-2019 (COVID-19) led the World Health Organization to declare this disease a pandemic. Initial epidemiological data showed that patients with cancer were at high risk of developing severe forms of COVID-19. National scientific societies published recommendations modifying the patients' breast cancer (BC) management to preserve, in theory, quality oncologic care, avoiding the increased risk of contamination. The Senology International Society (SIS) decided to take an inventory of the actions taken worldwide. This study investigates COVID-19-related changes concerning BC management and analyzes the will to maintain them after the pandemic, evaluating their oncological safety consequences. MATERIALS AND METHODS: SIS network members participated in an online survey using a questionnaire (Microsoft® Forms) from June 15th to July 31st, 2020. RESULTS: Forty-five responses from 24 countries showed that screening programs had been suspended (68%); magnetic resonance imagines were postponed (73%); telemedicine was preferred when possible (71%). Surgeries were postponed: reconstructive (77%), for benign diseases (84%), and in patients with significant comorbidities (66%). Chemotherapy and radiotherapy protocols had been adapted in 28% of patients in both. Exception for telemedicine (34%), these changes in practice should not be continued. CONCLUSION: The SIS survey showed significant changes in BC's diagnosis and treatment during the first wave of the COVID-19 pandemic, but most of these changes should not be maintained. Indeed, women have fewer severe forms of COVID-19 and are less likely to die than men. The risk of dying from COVID-19 is more related to the presence of comorbidities and age than to BC. Stopping screening and delaying treatment leads to more advanced stages of BC. Only women aged over 65 with BC under treatment and comorbidities require adaptation of their cancer management.

Long-term water quality conditions and trends in 12 tropical coastal rivers in Northeast Brazil.

The water quality and trends in 12 tropical rivers in northeastern Brazil over a 27-year period (1990-2016; N = 39,008 samples) were evaluated. The analyzed parameters included temperature, conductivity, pH, dissolved oxygen (DO), biochemical oxygen demand (BOD), nitrogen (NH4+), total phosphorus (P), and fecal coliforms. Densely populated basins (> 1000 inhab km-2) presented lower DO values (average 3.4 mg l-1; 43% DO saturation), while those with low demographic density (< 100 inhab km-2) presented values that aligned well with the recommendations of environmental legislation (average 5.8 mg l-1; 75% DO saturation). The NH4+ and P compound concentrations were typical of water bodies affected by urban inputs. The average p values were above the allowable limit (< 0.1 mg l-1) at all stations. The NH4+ values were high at the stations showing low DO concentrations, which suggested that due to reducing conditions after NH4+ accumulation was favored in those aquatic systems. In densely populated basins, the average fecal coliform concentrations were > 40,000 MPN 100 ml-1, indicating the input of improperly treated domestic/industrial liquid wastes. For the period from 1990 to 2016, 45% of the stations (N = 19) showed a rate of DO reduction that ranged from 0.01 to 0.17 mg l-1.O2 year-1. An increase in NH4+ concentrations was observed in 33% of the stations (N = 14), with an estimated average increase rate from 0.013 to 1.8 mg l-1 NH4+ year-1. These results demonstrated that the rates of increase in anthropogenic factors were significant (p < 0.05), while the natural factors remained constant.

MicroRNA Biophysically Modulates Cardiac Action Potential by Direct Binding to Ion Channel.

BACKGROUND: MicroRNAs (miRs) play critical roles in regulation of numerous biological events, including cardiac electrophysiology and arrhythmia, through a canonical RNA interference mechanism. It remains unknown whether endogenous miRs modulate physiologic homeostasis of the heart through noncanonical mechanisms. METHODS: We focused on the predominant miR of the heart (miR1) and investigated whether miR1 could physically bind with ion channels in cardiomyocytes by electrophoretic mobility shift assay, in situ proximity ligation assay, RNA pull down, and RNA immunoprecipitation assays. The functional modulations of cellular electrophysiology were evaluated by inside-out and whole-cell patch clamp. Mutagenesis of miR1 and the ion channel was used to understand the underlying mechanism. The effect on the heart ex vivo was demonstrated through investigating arrhythmia-associated human single nucleotide polymorphisms with miR1-deficient mice. RESULTS: We found that endogenous miR1 could physically bind with cardiac membrane proteins, including an inward-rectifier potassium channel Kir2.1. The miR1-Kir2.1 physical interaction was observed in mouse, guinea pig, canine, and human cardiomyocytes. miR1 quickly and significantly suppressed IK1 at sub-pmol/L concentration, which is close to endogenous miR expression level. Acute presence of miR1 depolarized resting membrane potential and prolonged final repolarization of the action potential in cardiomyocytes. We identified 3 miR1-binding residues on the C-terminus of Kir2.1. Mechanistically, miR1 binds to the pore-facing G-loop of Kir2.1 through the core sequence AAGAAG, which is outside its RNA interference seed region. This biophysical modulation is involved in the dysregulation of gain-of-function Kir2.1-M301K mutation in short QT or atrial fibrillation. We found that an arrhythmia-associated human single nucleotide polymorphism of miR1 (hSNP14A/G) specifically disrupts the biophysical modulation while retaining the RNA interference function. It is remarkable that miR1 but not hSNP14A/G relieved the hyperpolarized resting membrane potential in miR1-deficient cardiomyocytes, improved the conduction velocity, and eliminated the high inducibility of arrhythmia in miR1-deficient hearts ex vivo. CONCLUSIONS: Our study reveals a novel evolutionarily conserved biophysical action of endogenous miRs in modulating cardiac electrophysiology. Our discovery of miRs' biophysical modulation provides a more comprehensive understanding of ion channel dysregulation and may provide new insights into the pathogenesis of cardiac arrhythmias.

Management of non-invasive tumours, benign tumours and breast cancer during the COVID-19 pandemic: recommendations based on a Latin American survey.

INTRODUCTION: The COVID-19 pandemic has changed health systems across the world, both in general hospitals and in oncology institutes or centres.For cancer specialists, particularly breast cancer (BC), the COVID-19 pandemic represents a combination of challenges since the hospital resources and staff have become more limited; this has obliged oncology specialists to seek a consensus and establish which patients with BC require more urgent attention and which patients can wait until there is a better control of this pandemic. The health system in Latin America has some special characteristics; in some of the countries, there are shortages which limit access to several specialities (surgery, clinical oncology and radiotherapy) in some regions. OBJECTIVE: After a systematic review of the most recent literature regarding the management of BC during the COVID-19 pandemic, the main objective is to understand the position of the different Latin American Societies of Mastology in terms of available alternatives for the treatment of BC. METHODS: After carrying out a comprehensive and exhaustive search of the most recent guides on the management of BC during the COVID-19 pandemic, the board members of the Latin American Federation of Mastology invited, via email, different specialists, all experts in BC care, to complete an anonymous survey online.The survey was distributed between 30 and 10 May 2020. The survey included 27 questions on four topics: demographic information, consultations, imaging and treatment of BC.The questionnaire was sent and then distributed to various health specialists including breast surgeons, clinical oncologists, radiation oncologists and radiologists via the Presidents of the different Latin American Societies of Mastology in 18 countries. The results are summarised as tallies based on the number of responses to each question. RESULTS: A total of 499 responses were received. The majority of the respondents were males (275 (55.11%)); 290 participants were over 45 years (58.11%).The questionnaire presented those surveyed with three possible answers (agree, disagree and neither agree nor disagree). The results reflect that there was consensus in the majority of situations presented. Only seven questions revealed disagreement among those responding. The results are presented as recommendations. CONCLUSION: The management of patients with BC presents unique challenges during the current world health situation produced by COVID-19 pandemic. Breast care specialists (surgical oncologists, breast care clinicians, clinical oncologists, radiation oncologists and radiologists) from 18 countries in Central and South America submitted through their responses and recommendations for the treatment of BC during the COVID-19 pandemic.

Rhizosphere microbiological processes and eucalypt nutrition: Synthesis and conceptualization.

In this review, we present the state of art regarding rhizosphere effects on eucalypt plantations. It provides a greater understanding of carbon (C) and nitrogen (N) turnover in forest soils. P organic hydrolysis, soil mineral solubilization, indoleacetic acid, gibberellin, resistance factors, and production of siderophores by rhizosphere microbial populations help to explain the tolerance of Eucalyptus plants to biotic and abiotic stresses and the apparent steady-state condition of C and N soil stocks in many planted forests. This work aims to present the main findings on Eucalyptus rhizosphere processes and highlights their importance for trees nutrition, especially for N mineralization triggered by microbial activation or microbial community structure changes regarding the so-called rhizosphere priming effect and N fixation. Furthermore, we present an explanatory conceptual model of the steady-state condition for soil organic matter (SOM) stocks and its relation with fertilization based on a nutrient balance model. This review also considers the main experimental and modeling studies that demonstrate the quantitative importance of rhizosphere processes to Eucalyptus genus and their shortcomings. This provides a framework for process modeling under scenarios of global climate change. A better understanding of rhizosphere microbiological processes may allow improvements in Eucalyptus nutrition and production, as well as in accurate long-term estimates of SOM stocks and C-CO2 exchanges between forest soils and the atmosphere.

Identification of potential allosteric binding sites in cathepsin K based on intramolecular communication.

Network theory methods and molecular dynamics (MD) simulations are accepted tools to study allosteric regulation. Indeed, dynamic networks built upon correlation analysis of MD trajectories provide detailed information about communication paths between distant sites. In this context, we aimed to understand whether the efficiency of intramolecular communication could be used to predict the allosteric potential of a given site. To this end, we performed MD simulations and network theory analyses in cathepsin K (catK), whose allosteric sites are well defined. To obtain a quantitative measure of the efficiency of communication, we designed a new protocol that enables the comparison between properties related to ensembles of communication paths obtained from different sites. Further, we applied our strategy to evaluate the allosteric potential of different catK cavities not yet considered for drug design. Our predictions of the allosteric potential based on intramolecular communication correlate well with previous catK experimental and theoretical data. We also discuss the possibility of applying our approach to other proteins from the same family.