Demographic structure across all known populations of the rheophyte Dyckia brevifolia Baker (Bromeliaceae) in the Itajaí-Açu River, Southern Brazil

Understanding the distribution and demographic structure of populations is essential for species conservation. In Brazil, the rheophyte group has been greatly affected by the construction of hydroelectric dams. All know populations of Dyckia brevifolia Baker along Itajaí-Açu River were studied. The plants were classified as seedlings, immature or reproductive rosettes. In addition, the number of dead rosettes, except for seedlings, was determined in five populations of D. brevifolia. The total number of rosettes per population ranged from 273 to 7,185, totaling 30,443 rosettes, and 1,789 seedlings (5.9%). Only 2.4% of rosettes occurred isolated and 97.6% occurred clumped into 2,254 clumps. The number of rosettes per clump ranged from two to 339 rosettes. The percentage of reproductive rosettes per population ranged from 7.8 to 26.7%. The correlation between the number of clumps or between the total number of rosettes and the area of occupation was significant and positive (r = 0.82; P < 0.05). The production of offshoots (1-4) occurred on immature and reproductive rosettes. Dyckia brevifolia has herbivory by Hydrochaeris hydrochaeris (capybara). These rosettes die or often resprout, emitting from 1 to 20 shoots. The populations did not present a pattern of distribution of rosettes in the diametric classes, but in all populations a decrease in the number of rosettes can be observed in the classes with the largest diameter. The small area of occupation (9,185 m2) showed high environmental specificity and vulnerable to habitat loss and environmental changes. Therefore, the maintenance these sites is essential for the long-term conservation of D. brevifolia.

Autophagy buffers Ras-induced genotoxic stress enabling malignant transformation in keratinocytes primed by human papillomavirus

Malignant transformation involves an orchestrated rearrangement of cell cycle regulation mechanisms that must balance autonomic mitogenic impulses and deleterious oncogenic stress. Human papillomavirus (HPV) infection is highly prevalent in populations around the globe, whereas the incidence of cervical cancer is 0.15%. Since HPV infection primes cervical keratinocytes to undergo malignant transformation, we can assume that the balance between transforming mitogenic signals and oncogenic stress is rarely attained. We showed that highly transforming mitogenic signals triggered by HRasG12V activity in E6E7-HPV-keratinocytes generate strong replication and oxidative stresses. These stresses are counteracted by autophagy induction that buffers the rapid increase of ROS that is the main cause of genotoxic stress promoted by the oncoprotein. As a result, autophagy creates a narrow window of opportunity for malignant keratinocytes to emerge. This work shows that autophagy is crucial to allow the transition of E6E7 keratinocytes from an immortalized to a malignant state caused by HRasG12V.

Transcription activity contributes to the firing of non-constitutive origins in African trypanosomes helping to maintain robustness in S-phase duration

The co-synthesis of DNA and RNA potentially generates conflicts between replication and transcription, which can lead to genomic instability. In trypanosomatids, eukaryotic parasites that perform polycistronic transcription, this phenomenon and its consequences are still little studied. Here, we showed that the number of constitutive origins mapped in the Trypanosoma brucei genome is less than the minimum required to complete replication within S-phase duration. By the development of a mechanistic model of DNA replication considering replication-transcription conflicts and using immunofluorescence assays and DNA combing approaches, we demonstrated that the activation of non-constitutive (backup) origins are indispensable for replication to be completed within S-phase period. Together, our findings suggest that transcription activity during S phase generates R-loops, which contributes to the emergence of DNA lesions, leading to the firing of backup origins that help maintain robustness in S-phase duration. The usage of this increased pool of origins, contributing to the maintenance of DNA replication, seems to be of paramount importance for the survival of this parasite that affects million people around the world.

Fibroblast Growth Factor 2 lethally sensitizes cancer cells to stress-targeted therapeutic inhibitors

In malignant transformation, cellular stress‐response pathways are dynamically mobilized to counterbalance oncogenic activity, keeping cancer cells viable. Therapeutic disruption of this vulnerable homeostasis might change the outcome of many human cancers, particularly those for which no effective therapy is available. Here, we report the use of fibroblast growth factor 2 (FGF2) to demonstrate that further mitogenic activation disrupts cellular homeostasis and strongly sensitizes cancer cells to stress‐targeted therapeutic inhibitors. We show that FGF2 enhanced replication and proteotoxic stresses in a K‐Ras‐driven murine cancer cell model, and combinations of FGF2 and proteasome or DNA damage response‐checkpoint inhibitors triggered cell death. CRISPR/Cas9‐mediated K‐Ras depletion suppressed the malignant phenotype and prevented these synergic toxicities in these murine cells. Moreover, in a panel of human Ewing's sarcoma family tumor cells, sublethal concentrations of bortezomib (proteasome inhibitor) or VE‐821 (ATR inhibitor) induced cell death when combined with FGF2. Sustained MAPK‐ERK1/2 overactivation induced by FGF2 appears to underlie these synthetic lethalities, as late pharmacological inhibition of this pathway restored cell homeostasis and prevented these described synergies. Our results highlight how mitotic signaling pathways which are frequently overridden in malignant transformation might be exploited to disrupt the robustness of cancer cells, ultimately sensitizing them to stress‐targeted therapies. This approach provides a new therapeutic rationale for human cancers, with important implications for tumors still lacking effective treatment, and for those that frequently relapse after treatment with available therapies.

Reproductive ecology of Ocotea catharinensis, an endangered tree species

Ocotea catharinensis (Lauraceae) is an endangered tree species from the Brazilian Atlantic Rainforest. Currently, little is known about the reproductive ecology of this species. Aiming to propose conservation measures, we described aspects related to phenology, floral biology, pollination, seed dispersal and mating system of O. catharinensis. We conducted phenological observations in 62 individuals for 2 years. In one reproductive event, we evaluated nectar production, stigmatic receptivity and pollen viability. Floral visitors were observed, identified and classified on a scale of pollination effectiveness. Seed dispersers were observed and identified using camera traps. Finally, the mating system was evaluated through pollen/ovule ratios, experimental pollination treatments and genetic analysis with molecular markers. Ocotea catharinensis presented a supra-annual fruiting pattern with a substantial reduction of reproducing individuals from bud phase to ripe fruit phase. Several mechanisms prompting cross-fertilisation were identified, such as attractive, herkogamic and protogynic flowers. The main floral visitors and pollinators were from the Diptera order, and all seed dispersers were birds. The species presented a predominantly outcrossed mixed mating system with significant selfing rate (17.3%). Although based on restricted evidence, we hypothesised that selfing is an escape mechanism for situations unfavourable to cross-fertilisation. Specifically, for the studied population selfing is a response to reduced population size, which is caused by the non-reproduction of all potentially reproductive individuals and by past exploitation events. Therefore, conservation efforts should be able to enhance population sizes, as well as prevent overexploitation.

A data-driven approach for the study of coagulation phenomena in waste lubricant oils and its relevance in alkaline regeneration treatments

Coagulation phenomena can occur in certain types of waste lubricant oils (WLO) during regeneration processes involving alkaline treatments, causing plant shutdowns. In this context, this study addresses the nature of the compounds responsible for the coagulation phenomena after the alkaline treatment. For such, an empirical test was developed to assess the coagulation behaviour of WLO, consisting in the addition of KOH to the WLO followed by heating under stirring conditions. This test was performed on 133 samples and four coagulation classes were identified: A; B1; B2 and C. Moreover, a physicochemical characterization of WLO was carried out regarding viscosity at 40°C, saponification number (SN), total acid number (TAN), surface tension, water content, elemental analysis and functional groups (FTIR). 56 samples of fresh lubricant oils for different applications were also characterized and their properties assessed and compared. Multivariate methods were applied to WLO to discriminate among coagulation classes based on FTIR spectra. It was found that coagulation classes A and B1 exhibit statistically similar patterns for all properties determined. Spectral discriminating analysis did not reveal discriminant peaks for class B1 samples, and the presence of specific additives was pointed as the possible factor underlying the increase in viscosity in this oils. Class B2 presents the absence of additives and oxidation products as differentiating features. In addition, B2 samples showed lower TAN SN, and lower concentration of some elements. Lubricants from gear or hydraulic applications can give rise to this class of WLO. Oils of Class C are mainly composed by synthetic ester type base oils, which hamper regeneration processes using alkaline pretreatments. In future studies, WLO type A and B1 can be classified as a single class. The coagulation phenomena classification becomes A - negative, B - precipitate formation and C - positive.

Sorption, degradation and transport phenomena of alcohol ethoxysulfates in agricultural soils. Laboratory studies

In the present work, laboratory studies were conducted in order to determine and model the sorption, degradation and transport processes of alcohol ethoxysulfates (AES), one of the most important groups of anionic surfactants. Adsorption/desorption isotherms were obtained for several structurally related AES ethoxymers (homologue AES-C₁₂E_n with n = 0-10 ethoxymer units and homologue AES-C₁₄E_n with n = 0-7 ethoxymer units) using a batch equilibrium method. Data were fitted to a linear and a Freundlich isotherm models. Additionally, experiments in continuous-flow soil columns were also carried out and the breakthrough curves observed for each compound were studied. Breakthrough curves were used to determine the fundamental parameters of the transport model (hydrodynamic dispersion coefficient, degradation rate constant and adsorption/desorption isotherm slope), that is the main phenomena that take place simultaneously when AES move through agricultural soil. When the results obtained for the AES ethoxymers are combined, they reveal a clear and consistent trend towards a sorption increase with the number of ethoxylated units and with the length of the alkyl chain that opens the possibility to estimate the values of the transport parameters for other structurally related ethoxymers.

Development and validation of the first SSR markers for Mimosa scabrella Benth

Mimosa scabrella Benth., popularly known as ''bracatinga'', is a pioneer and endemic species of Brazil, occurring in Mixed Ombrophilous Forest associated with Brazilian Atlantic Rainforest biomes. It is a fast-growing tree of the Fabaceae family that facilitates the dynamics of ecological succession. SSR development, when there is no genome sequence, is time and labor intensive and there are no molecular markers for M. scabrella. We developed and validated the first microsatellite markers for this tetraploid species, evaluating mother trees and progenies. Using Illumina sequencing, we identified 290 SSR loci and 211 primer pairs. After 31 SSR loci PCR/agarose electrophoresis selection, a subset of 11 primer pairs was synthetized with fluorescence in the forward primer for PCR and capillary electrophoresis validation with leaf DNA of 33 adult and 411 progeny individuals. Polymorphic locus percentage was 36, 4 in 11 loci, 3 chloroplast SSRs, and 1 nuclear SSR. Allele number of polymorphic loci ranged from 2 to 11 alleles considering all sampling. All 11 primer pairs were also tested for cross-species amplification for five Fabaceae-Mimosoideae species, ranging from 2 loci transferred to Calliandra tweedii Benth. and all 11 loci transferred to Mimosa taimbensis Burkart. The assessed and validated SSR markers for M. scabrella are suitable and useful for analysis and population genetic studies.

An Interdisciplinary Approach for Designing Kinetic Models of the Ras/MAPK Signaling Pathway

We present in this article a methodology for designing kinetic models of molecular signaling networks, which was exemplarily applied for modeling one of the Ras/MAPK signaling pathways in the mouse Y1 adrenocortical cell line. The methodology is interdisciplinary, that is, it was developed in a way that both dry and wet lab teams worked together along the whole modeling process.

Chemical disorder determines the deviation of the Slater-Pauling rule for Fe2MnSi-based Heusler alloys: evidences from neutron diffraction and density functional theory

Fe2MnSi fails to follow the Slater-Pauling rule. This phenomenon is thought to originate from either: (i) an antiferromagnetic arrangement of Mn ions at low temperature and/or (ii) chemical disorder. An important insight on this issue could be achieved by considering Fe2MnSi1-x Ga x compounds, thoroughly studied here by means of magnetization, neutron diffraction and density functional calculations (DFT). Our results indicate that chemical disorder (and not the antiferromagnetic arrangement) is responsible for the deviation of the Slater-Pauling rule on Fe2MnSi-based Heusler alloys. Furthermore, evidences suggest that Ga substitution into Si site favors the Fe/Mn disorder, further enhancing the observed deviation.

A New Approach for Identification of Cancer-related Pathways using Protein Networks and Genomic Data

Cancer cells have anomalous development and proliferation due to disturbances in their control systems. The study of the behavior of cellular control system requires high-throughput dynamical data. Unfortunately, this type of data is not largely available. This fact motivates the main issue of this article: how to use static omics data and available biological knowledge to get new information about the elements of the control system in cancer cells. Two important measures to access the state of the cellular control system are the gene expression profile and the signaling pathways. This article uses a combination of these two static omics data to gain insights on the states of a cancer cell. To extract information from this kind of data, a statistical computational model was formalized and implemented. In order to exemplify the application of some aspects of the developed conceptual framework, we verified the hypothesis that different types of cancer cells have different disturbed signaling pathways. To this end, we developed a method that recovers small protein networks, called motifs, which are differentially represented in some subtypes of breast cancer. These differentially represented motifs are enriched with specific gene ontologies as well as with new putative cancer genes.

Wide-range and accurate modeling of linear alkylbenzene sulfonate (LAS) adsorption/desorption on agricultural soil

In this paper, rigorous data and adequate models about linear alkylbenzene sulfonate (LAS) adsorption/desorption on agricultural soil are presented, contributing with a substantial improvement over available adsorption works. The kinetics of the adsorption/desorption phenomenon and the adsorption/desorption equilibrium isotherms were determined through batch studies for total LAS amount and also for each homologue series: C10, C11, C12 and C13. The proposed multiple pseudo-first order kinetic model provides the best fit to the kinetic data, indicating the presence of two adsorption/desorption processes in the general phenomenon. Equilibrium adsorption and desorption data have been properly fitted by a model consisting of a Langmuir plus quadratic term, which provides a good integrated description of the experimental data over a wide range of concentrations. At low concentrations, the Langmuir term explains the adsorption of LAS on soil sites which are highly selective of the n-alkyl groups and cover a very small fraction of the soil surface area, whereas the quadratic term describes adsorption on the much larger part of the soil surface and on LAS retained at moderate to high concentrations. Since adsorption/desorption phenomenon plays a major role in the LAS behavior in soils, relevant conclusions can be drawn from the obtained results.

Evaluation of Linear Alkylbenzene Sulfonate (LAS) behaviour in agricultural soil through laboratory continuous studies

The behaviour of Linear Alkylbenzene Sulfonate (LAS) in agricultural soil is investigated in the laboratory using continuous-flow soil column studies in order to simultaneously analyze the three main underlying phenomena (adsorption/desorption, degradation and transport). The continuous-flow soil column experiments generated the breakthrough curves for each LAS homologue, C10, C11, C12 and C13, and by adding them up, for total LAS, from which the relevant retention, degradation and transport parameters could be estimated, after proposing adequate models. Several transport equations were considered, including the degradation of the sorbate in solution and its retention by soil, under equilibrium and non-equilibrium conditions between the sorbent and the sorbate. In general, the results obtained for the estimates of those parameters that were common to the various models studied (such as the isotherm slope, first order degradation rate coefficient and the hydrodynamic dispersion coefficient) were rather consistent, meaning that mass transfer limitations are not playing a major role in the experiments. These three parameters increase with the length of the LAS homologue chain. The study will provide the underlying conceptual framework and fundamental parameters to understand, simulate and predict the environmental behaviour of LAS compounds in agricultural soils.

Evaluation of the presence of major anionic surfactants in marine sediments

The contamination of aquatic environments has become the focus of increasing regulation and public concern due to their potential and unknown negative effects on the ecosystems. The present work develops a monitoring and statistical study, based on the analysis of variance test (ANOVA) and the multivariable analysis, both for insoluble soap and LAS in order to compare the behavior of different anionic surfactants in this environmental compartment. First, a novel and successfully validated methodology to analyze insoluble soap in these samples is developed. The matrix effect and the comparison of different extraction techniques were also performed. The optimized analytical methodologies were applied to 48 representative samples collected from the Almeria Coast (Spain) and then a statistical analysis to correlate anionic surfactant concentration and several variables associated with marine sediment samples was also developed. The results obtained showed relevant conclusions related to the environmental behavior of anionic surfactants in marine sediments.

Finite-size analysis of a two-dimensional Ising model within a nonextensive approach

In this work we present a thorough analysis of the phase transitions that occur in a ferromagnetic two-dimensional Ising model, with only nearest-neighbors interactions, in the framework of the Tsallis nonextensive statistics. We performed Monte Carlo simulations on square lattices with linear sizes L ranging from 32 up to 512. The statistical weight of the Metropolis algorithm was changed according to the nonextensive statistics. Discontinuities in the m(T) curve are observed for q< or =0.5 . However, we have verified only one peak on the energy histograms at the critical temperatures, indicating the occurrence of continuous phase transitions. For the 0.5<q< or =1.0 regime, we have found continuous phase transitions between the ordered and the disordered phases, and determined the critical exponents via finite-size scaling. We verified that the critical exponents alpha , beta , and gamma depend on the entropic index q in the range 0.5<q< or =1.0 in the form alpha(q)=(10q2-33q+23)/20 , beta(q)=(2q-1)/8 , and gamma(q)=(q2-q+7)/4 . On the other hand, the critical exponent nu does not depend on q . This suggests a violation of the scaling relations 2beta+gamma=dnu and alpha+2beta+gamma=2 and a nonuniversality of the critical exponents along the ferro-paramagnetic frontier.

Understanding the inverse magnetocaloric effect in antiferro- and ferrimagnetic arrangements

The inverse magnetocaloric effect occurs when a magnetic material cools down under applied magnetic field in an adiabatic process. Although the existence of the inverse magnetocaloric effect was recently reported experimentally, a theoretical microscopic description is almost nonexistent. In this paper we theoretically describe the inverse magnetocaloric effect in antiferro- and ferrimagnetic systems. The inverse magnetocaloric effects were systematically investigated as a function of the model parameters. The influence of the Néel and the compensation temperature on the magnetocaloric effect is also analyzed using a microscopic model.

Effects of age and physical activity on the autonomic control of heart rate in healthy men

The effects of the aging process and an active life-style on the autonomic control of heart rate (HR) were investigated in nine young sedentary (YS, 23 +/- 2.4 years), 16 young active (YA, 22 +/- 2.1 years), 8 older sedentary (OS, 63 +/- 2.4 years) and 8 older active (OA, 61 +/- 1.1 years) healthy men. Electrocardiogram was continuously recorded for 15 min at rest and for 4 min in the deep breathing test, with a breath rate of 5 to 6 cycles/min in the supine position. Resting HR and RR intervals were analyzed by time (RMSSD index) and frequency domain methods. The power spectral components are reported in normalized units (nu) at low (LF) and high (HF) frequency, and as the LF/HF ratio. The deep breathing test was analyzed by the respiratory sinus arrhythmia indices: expiration/inspiration ratio (E/I) and inspiration-expiration difference (deltaIE). The active groups had lower HR and higher RMSSD index than the sedentary groups (life-style condition: sedentary vs active, P < 0.05). The older groups showed lower HFnu, higher LFnu and higher LF/HF ratio than the young groups (aging effect: young vs older, P < 0.05). The OS group had a lower E/I ratio (1.16) and deltaIE (9.7 bpm) than the other groups studied (YS: 1.38, 22.4 bpm; YA: 1.40, 21.3 bpm; OA: 1.38, 18.5 bpm). The interaction between aging and life-style effects had a P < 0.05. These results suggest that aging reduces HR variability. However, regular physical activity positively affects vagal activity on the heart and consequently attenuates the effects of aging in the autonomic control of HR.

Comparative genomics of two Leptospira interrogans serovars reveals novel insights into physiology and pathogenesis

Leptospira species colonize a significant proportion of rodent populations worldwide and produce life-threatening infections in accidental hosts, including humans. Complete genome sequencing of Leptospira interrogans serovar Copenhageni and comparative analysis with the available Leptospira interrogans serovar Lai genome reveal that despite overall genetic similarity there are significant structural differences, including a large chromosomal inversion and extensive variation in the number and distribution of insertion sequence elements. Genome sequence analysis elucidates many of the novel aspects of leptospiral physiology relating to energy metabolism, oxygen tolerance, two-component signal transduction systems, and mechanisms of pathogenesis. A broad array of transcriptional regulation proteins and two new families of afimbrial adhesins which contribute to host tissue colonization in the early steps of infection were identified. Differences in genes involved in the biosynthesis of lipopolysaccharide O side chains between the Copenhageni and Lai serovars were identified, offering an important starting point for the elucidation of the organism's complex polysaccharide surface antigens. Differences in adhesins and in lipopolysaccharide might be associated with the adaptation of serovars Copenhageni and Lai to different animal hosts. Hundreds of genes encoding surface-exposed lipoproteins and transmembrane outer membrane proteins were identified as candidates for development of vaccines for the prevention of leptospirosis.

Medicinal plants popularly used in the Brazilian Tropical Atlantic Forest

A survey of medicinal plants used by rural and urban inhabitants of the three cities of the Tropical Atlantic Forest, Region of Vale do Ribeira, State of São Paulo, Brazil was performed by means of 200 interviews with medicinal plant users and extractors and, traditional healers. One hundred fourteen herbal remedies were recorded and the following information reported: Latin, vernacular and English names, plant part used, forms of preparation and application of the herbal remedies, medicinal or food uses, areas of plant collection, economic importance (when available) and other data.

Selective breeding of mice for antibody responsiveness to flagellar and somatic antigens of salmonellae

Selective breeding has been performed in mice for their high or low antibody responsiveness to Salmonella antigens (Ag). Two noncross-reacting Salmonellae (S. typhimurium and S. oranienburg) have been alternately used to immunize successive generations in order to avoid interference of maternally transmitted antibody. Both Salmonellae carry two independent antigens: flagellar (f) and somatic (s). Two two-way selections were carried out: one for agglutinin response to fAg and the other for agglutinin response to sAg (Selection Ags). The agglutinin response to the other independent Ag was also measured (Associated Ags). The phenotypic character chosen for selection is the maximal agglutinin titer in response to optimal immunization. In both selections, high and low responder lines diverged progressively. There was a 27-fold interline difference in the F13 generation of selection for fAg response and a 38-fold one in the F11 generation of selection for sAg response. This divergence and the continuous distribution of phenotypes in the foundation population indicate that the quantitative character investigated is subject to polygenic regulation. The realized heritability (h2) of the character, measured from the interline divergence, was 0.18 +/- 0.06 in both f and s selections. This means that about 20% of the phenotypic variance of the foundation population is additive. The modification of immune responsiveness to the selection Ag produced by selective breeding was accompanied by a parallel and equivalent effect on immune responsiveness to the noncross-reacting Associated Ag. This effect is therefore entirely nonspecific. A small but definite sex effect in favor of female antibody responsiveness was demonstrated. The results are discussed in comparison with other selection experiments made in mice for quantitative antibody response to other antigens.