New conservation opportunities: Using citizen science in monitoring non-native species in Neotropical region

The combination of highly equipped smartphones, with the increased use of social media, has offered a wide database. Given this, citizen science can be used to record and monitor non-native fish fauna, target new samples and collaborate with monitoring occurrences in new areas. We aimed to demonstrate the efficiency of social media in citizen science as a tool to cooperate with monitoring studies of non-native species. Consequently, we determined the occurrence points of S. brasiliensis in the Iguaçu River basin, indicating sites of greatest occurrence and analyzing the impact of the invasion on the native fauna of the basin. Files and information available on the YouTube^® and Facebook^® media platforms were used as data, was carried out from April 2019 to April 2020. The results were 40 records, 22 videos obtained from Youtube, and seven videos and 11 photos from Facebook, the oldest record was from April 2013, while the largest number of posts was in 2016. Fish records available from online platforms can reveal the occurrence and progressive dispersion of species, in the context of biological invasions, these tools can be of great value in studies that aim to follow the progress of introduced species, contributing by helping to direct new sampling programs and corroborating the occurrence of species in new areas in conjunction with standard monitoring programs. Based on citizen science records, it was possible to update the range of occurrence of the non-native S. brasiliensis in the Iguaçu River basin, cooperating with scientific knowledge. Innovative monitoring and control measures are necessary to deal with invasive species, with citizen science proving to be competent for determining the occurrence of species and showing promise in the entire field of ichthyology.     

Alarm scent-marking during predatory attempts in the Cabrera vole (Microtus cabrerae Thomas, 1906)

The alarm pheromones often released by animals under stressful situations seem to elicit behavioral changes in conspecifics, which in the appropriate context can be viewed as anti-predatory responses. However, the releasing of alarm pheromones associated with predatory events has not been demonstrated in mammals. In the current study with wild-caught Cabrera voles, we carried out experiments in the laboratory and in the field to assess the release of alarm pheromones in scent-marks during simulated predatory events and disclose their effects on conspecifics. We first conducted an assay wherein voles where let to scent-mark a clean substrate in the absence of disturbance (control) and under the simulation of predatory events. Contrarily to the control, no fecal boli were released and the area marked with urine was significantly larger during the predatory simulation. In a subsequent assay, we assessed the voles’ preference between urine-marks released under predatory simulation and in control conditions. Voles showed a significant preference by control substrates. Finally, a third assay was carried out in the vole’s habitat wherein the individual activity was monitored by radio-tracking before and after placement of urine-marks obtained during the conditions described above. The vole’s activity was only reduced near the urine-marks released during the simulated predatory events. The results suggest that: (1) during predatory attempts, Cabrera voles release an alarm pheromone in their urine-marks; (2) the putative alarm pheromone reduces the voles’ activity in the surroundings of the marked area; (3) the putative alarm pheromone persists in the field affecting conspecifics’ activity for several days.     

HLA-A*01 allele: a risk factor for dengue haemorrhagic fever in Brazil's population

Severe forms of dengue, such as dengue haemorrhagic fever (DHF) and dengue shock syndrome, are examples of a complex pathogenic mechanism in which the virus, environment and host immune response interact. The influence of the host's genetic predisposition to susceptibility or resistance to infectious diseases has been evidenced in several studies. The association of the human leukocyte antigen gene (HLA) class I alleles with DHF susceptibility or resistance has been reported in ethnically and geographically distinct populations. Due to these ethnic and viral strain differences, associations occur in each population, independently with a specific allele, which most likely explains the associations of several alleles with DHF. As the potential role of HLA alleles in the progression of DHF in Brazilian patients remains unknown, we then identified HLA-A alleles in 67 patients with dengue fever and 42 with DHF from Rio de Janeiro, Brazil, selected from 2002-2008 by the sequence-based typing technique. Statistical analysis revealed an association between the HLA-A*01 allele and DHF [odds ratio (OR) = 2.7, p = 0.01], while analysis of the HLA-A*31 allele (OR = 0.5, p = 0.11) suggested a potential protective role in DHF that should be further investigated. This study provides evidence that HLA class I alleles might be important risk factors for DHF in Brazilian patients.     

Impairment of the organization of locomotor and exploratory behaviors in bile duct-ligated rats

Hepatic encephalopathy (HE) arises from acute or chronic liver diseases and leads to several problems, including motor impairment. Animal models of chronic liver disease have extensively investigated the mechanisms of this disease. Impairment of locomotor activity has been described in different rat models. However, these studies are controversial and the majority has primarily analyzed activity parameters. Therefore, the aim of the present study was to evaluate locomotor and exploratory behavior in bile duct-ligated (BDL) rats to explore the spatial and temporal structure of behavior. Adult female Wistar rats underwent common bile duct ligation (BDL rats) or the manipulation of common bile duct without ligation (control rats). Six weeks after surgery, control and BDL rats underwent open-field, plus-maze and foot-fault behavioral tasks. The BDL rats developed chronic liver failure and exhibited a decrease in total distance traveled, increased total immobility time, smaller number of rearings, longer periods in the home base area and decreased percentage of time in the center zone of the arena, when compared to the control rats. Moreover, the performance of the BDL rats was not different from the control rats for the elevated plus-maze and foot-fault tasks. Therefore, the BDL rats demonstrated disturbed spontaneous locomotor and exploratory activities as a consequence of altered spatio-temporal organization of behavior.     

Influence of Soil Physical Properties on Plants of the Mussununga Ecosystem, Brazil

Distribution ranges of plant species are related to physical variables of ecosystems that limit plant growth. Therefore, each plant species response to physical factors builds up the functional diversity of an ecosystem. The higher the species richness of an ecosystem, the larger the probability of maintaining functions and the higher the potential number of plant functional groups (FGs). Thus, the richness potentially increases the number of functions of the highly diverse Atlantic Rainforest domain in Brazil. Severe plant growth limitations caused by stress, however, decrease species richness. In the Spodosols of the Mussununga, an associated ecosystem of Atlantic Rainforest, the percentage of fine sand is directly related to water retention. Moreover, the depth of the cementation layer in the Mussununga??s sandy soil is a physical factor that can affect the plants?? stress gradients. When a shallow cementation layer depth is combined with low water retention in soils and with low fine sand percentage, the double stresses of flooding in the rainy season and water scarcity in the dry season result. This study aimed to identify FGs among Mussununga plant species responding to water stress gradients of soil and to verify the effects of the gradients on plant species richness of the Mussununga. A canonical correspondence analysis (CCA) of species abundance and soil texture variables was performed on 18 plots in six physiognomies of the Mussununga. Species richness rarefactions were calculated for each vegetation form to compare diversity. The two main axes of the CCA showed two FGs responding to soil texture and cementation layer depth: stress tolerator species and mesic species. Physical variables affect plant diversity, with species richness rising as the fine sand proportion also rises in the Mussununga. The effect of the cementation layer is not significantly related to species richness variation.     

Microenvironmental Scenario of the Bone Marrow of Inorganic Arsenic-Exposed Experimental Mice

Exposure to arsenic on a regular basis, mainly through drinking water, agricultural pesticide, and sometimes therapeutic dose, results in various diseases of different tissues including the bone marrow hematopoietic system. Hematopoiesis is a dynamic process by which bone marrow (BM) hematopoietic stem/progenitor cells (HSPCs) generate a relatively constant pool of functionally mature blood cells by the support of microenvironmental components. The present study has been aimed to understand stem cell microenvironmental status during arsenic toxicity and the consequent reflection of dysregulation involving the hematopoietic machinery in experimental mice. Swiss albino mice were experimentally exposed to 10 μg arsenic trioxide/g body weight through oral gavage and 5 μg arsenic trioxide/g body weight intraperitoneally for a period of 30 days. Altered hemogram values in peripheral blood reflected the impaired hematopoiesis which was further validated by the reduced BM cellularity along with the deviated BM cell morphology as observed by scanning electron microscopy post arsenic exposure. The stromal cells were unable to establish a healthy matrix and the sustainability of hematopoietic progenitors was drastically affected in arsenic-exposed mouse groups, as observed in in vitro explant culture. The inability of stromal cells to establish supportive matrix was also explained by the decreased adherent colony formation in treated animals. Furthermore, the flow cytometric characterization of CXCR4⁺ and Sca-1⁺ CD44⁺ receptor expressions confirmed the dysregulation in the hematopoietic microenvironment. Thus, considering the importance of microenvironment in the maintenance of HSPC, it can be concluded that arsenic toxicity causes microenvironmental damage, leading to niche derangement and impaired hematopoiesis.     

Structural insights into dehydratase substrate selection for the borrelidin and fluvirucin polyketide synthases

Engineered polyketide synthases (PKSs) are promising synthetic biology platforms for the production of chemicals with diverse applications. The dehydratase (DH) domain within modular type I PKSs generates an α,β-unsaturated bond in nascent polyketide intermediates through a dehydration reaction. Several crystal structures of DH domains have been solved, providing important structural insights into substrate selection and dehydration. Here, we present two DH domain structures from two chemically diverse PKSs. The first DH domain, isolated from the third module in the borrelidin PKS, is specific towards a trans-cyclopentane-carboxylate-containing polyketide substrate. The second DH domain, isolated from the first module in the fluvirucin B₁ PKS, accepts an amide-containing polyketide intermediate. Sequence-structure analysis of these domains, in addition to previously published DH structures, display many significant similarities and key differences pertaining to substrate selection. The two major differences between BorA DH M3, FluA DH M1 and other DH domains are found in regions of unmodeled residues or residues containing high B-factors. These two regions are located between α3–β11 and β7–α2. From the catalytic Asp located in α3 to a conserved Pro in β11, the residues between them form part of the bottom of the substrate-binding cavity responsible for binding to acyl-ACP intermediates.

     

Elevation as a barrier: genetic structure for an Atlantic rain forest tree (Bathysa australis) in the Serra do Mar mountain range,SE Brazil

Distance and discrete geographic barriers play a role in isolating populations, as seed and pollen dispersal become limited. Nearby populations without any geographic barrier between them may also suffer from ecological isolation driven by habitat heterogeneity, which may promote divergence by local adaptation and drift. Likewise, elevation gradients may influence the genetic structure and diversity of populations, particularly those marginally distributed. Bathysa australis (Rubiaceae) is a widespread tree along the elevation gradient of the Serra do Mar, SE Brazil. This self‐compatible species is pollinated by bees and wasps and has autochoric seeds, suggesting restricted gene dispersal. We investigated the distribution of genetic diversity in six B. australis populations at two extreme sites along an elevation gradient: a lowland site (80–216 m) and an upland site (1010–1100 m.a.s.l.). Nine microsatellite loci were used to test for genetic structure and to verify differences in genetic diversity between sites. We found a marked genetic structure on a scale as small as 6 km (F_ST = 0.21), and two distinct clusters were identified, each corresponding to a site. Although B. australis is continuously distributed along the elevation gradient, we have not observed a gene flow between the extreme populations. This might be related to B. australis biological features and creates a potential scenario for adaptation to the different conditions imposed by the elevation gradient. We failed to find an isolation‐by‐distance pattern; although on the fine scale, all populations showed spatial autocorrelation until ~10‐20 m. Elevation difference was a relevant factor though, but we need further sampling effort to check its correlation with genetic distance. The lowland populations had a higher allelic richness and showed higher rare allele counts than the upland ones. The upland site may be more selective, eliminating rare alleles, as we did not find any evidence for bottleneck.     

Signalling mechanisms that regulate metabolic profile and autophagy of acute myeloid leukaemia cells

Acute myeloid leukaemia (AML) comprises a heterogeneous group of hematologic neoplasms characterized by diverse combinations of genetic, phenotypic and clinical features representing a major challenge for the development of targeted therapies. Metabolic reprogramming, mainly driven by deregulation of the nutrient‐sensing pathways as AMPK, mTOR and PI3K/AKT, has been associated with cancer cells, including AML cells, survival and proliferation. Nevertheless, the role of these metabolic adaptations on the AML pathogenesis is still controversial. In this work, the metabolic status and the respective metabolic networks operating in different AML cells (NB‐4, HL‐60 and KG‐1) and their impact on autophagy and survival was characterized. Data show that whereas KG‐1 cells exhibited preferential mitochondrial oxidative phosphorylation metabolism with constitutive co‐activation of AMPK and mTORC1 associated with increased autophagy, NB‐4 and HL‐60 cells displayed a dependent glycolytic profile mainly associated with AKT/mTORC1 activation and low autophagy flux. Inhibition of AKT is disclosed as a promising therapeutical target in some scenarios while inhibition of AMPK and mTORC1 has no major impact on KG‐1 cells’ survival. The results highlight an exclusive metabolic profile for each tested AML cells and its impact on determination of the anti‐leukaemia efficacy and on personalized combinatory therapy with conventional and targeted agents.     

Parasitism Behavior of Tetrastichus howardi (Hymenoptera: Eulophidae) on Larvae and Pupae of Sugarcane Borers

Journal of Insect Behavior - Control of the sugarcane borers, Diatraea saccharalis and Diatraea impersonatella (= D. flavipennella) (Lepidoptera: Crambidae), in Brazil, is based on mass release of...