High temporal and individual variation in the prevalence and intensity of chytrid infection in the southernmost Leaf Frog of the genus Pithecopus (Anura,Phyllomedusidae)

Hydrobiologia - Pithecopus rusticus is an endemic amphibian restricted to the type locality, in southern Brazil, and possibly endangered to extinction, due to habitat degradation. However, an...     

In Vitro Evaluation of the Effect of Stimulation with Magnetic Fields on Chondrocytes

Magnetic fields (MFs) have been used as an external stimulus to increase cell proliferation in chondrocytes and extracellular matrix (ECM) synthesis of articular cartilage. However, previously published studies have not shown that MFs are homogeneous through cell culture systems. In addition, variables such as stimulation times and MF intensities have not been standardized to obtain the best cellular proliferative rate or an increase in molecular synthesis of ECM. In this work, a stimulation device, which produces homogeneous MFs to stimulate cell culture surfaces was designed and manufactured using a computational model. Furthermore, an in vitro culture of primary rat chondrocytes was established and stimulated with two MF schemes to measure both proliferation and ECM synthesis. The best proliferation rate was obtained with an MF of 2 mT applied for 3 h, every 6 h for 8 days. In addition, the increase in the synthesis of glycosaminoglycans was statistically significant when cells were stimulated with an MF of 2 mT applied for 5 h, every 6 h for 8 days. These findings suggest that a stimulation with MFs is a promising tool that could be used to improve in vitro treatments such as autologous chondrocyte implantation, either to increase cell proliferation or stimulate molecular synthesis. Bioelectromagnetics. 2020;41:41–51 © 2019 Bioelectromagnetics Society     

Water Scarcity in the Andes: A Comparison of Local Perceptions and Observed Climate, Land Use and Socioeconomic Changes

In the Andean region of South America, understanding communities’ water perceptions is particularly important for water management as many rural communities must decide by themselves if and how they will protect their micro-watersheds and distribute their water. In this study we examine how Water User Associations in the Eastern Andes of Colombia perceive water scarcity and the relationship between this perception and observed climate, land use, and demographic changes. Results demonstrate a complex relationship between perceptions and observed changes. On the one hand, observed changes in land cover match perceptions of deforestation as the primary cause of increasing water scarcity. On the other hand, perceptions of climate driven changes in water availability are not reflected in observed precipitation data. Furthermore, water scarcity was perceived in regions where seasonal rainfall variability is higher but not in regions where annual rainfall is lower. We discuss how these results contribute to our understanding of adaptation to climate change and the implications of possible mismatches between environmental changes and local perceptions.     

A Case of Relapsed Chromoblastomycosis Due to Fonsecaea monophora: Antifungal Susceptibility and Phylogenetic Analysis

Chromoblastomycosis is a chronic cutaneous and subcutaneous mycosis. The management of this infection continues to be challenging because there is no consensus on the therapeutic regimen. We report here a case of a 69-year-old male patient with cauliflower-like lesions on his left leg and foot. He had already been treated with itraconazole at a dose of 200 mg/day for 5 months, with mycological cure for all the affected areas. However, the lesions relapsed at both sites, and treatment with itraconazole was resumed at the dose previously used. Initially, direct mycological examination, cultural, and microculture slide observation were performed. Afterward, sequencing of the ITS1-5.8S rDNA-ITS2 region of the fungal DNA and evaluation of its susceptibility to antifungal agents alone and in combination were performed. In direct mycological examination, the presence of sclerotic cells was verified, and the fungus was identified as Fonsecaea based on cultural and microscopic examinations. Identification as Fonsecaea monophora was confirmed after sequencing of the ITS region and phylogenetic analysis. The isolate was susceptible to itraconazole and terbinafine. The combinations of amphotericin B and terbinafine and terbinafine and voriconazole were synergistic. The use of drugs for which the causative agent is susceptible to singly or in combination may be an alternative for the treatment of mycosis. Furthermore, the identification of the agent by molecular techniques is important for epidemiological purposes. To the best of our knowledge, this is the first case of relapsed chromoblastomycosis caused by F. monophora in Brazil.     

Reproductive cycle of the European clam Ruditapes decussatus from Óbidos Lagoon,Leiria, Portugal

ABSTRACT

In Portugal, the European clam (Ruditapes decussatus) is an important commercial resource. Óbidos Lagoon is a strong candidate as a cultivation area to increase European clam exploitation. However, the reproductive biology of this population has not been described. In this work, the reproductive cycle of R. decussatus was characterized by determining gonadal development stages, gonad index, condition index, and biochemical composition. The relationship between reproduction and environmental parameters (sea surface temperature, chlorophyll a, and particulate organic matter) was assessed. Ruditapes decussatus had an annual reproductive cycle. The gametogenic cycle started in late winter, and the ripe stage in spring was followed by spawning that began at the end of spring/early summer and extended until early autumn. The subsequent period of sexual rest occurred during the winter. Condition index showed seasonal variations related to food availability (chlorophyll a). The European clams in Óbidos Lagoon recovered rapidly after their reproductive period, most likely owing to the availability of food. This study will help to improve sustainable management of this wild stock and is important for future aquaculture development of this species.     

Did the prion protein become vulnerable to misfolding after an evolutionary divide and conquer event?

Despite high sequence identity among mammalian prion proteins (PrPs), mammals have varying rates of susceptibility to prion disease resulting in a so-called species barrier. The species barrier follows no clear pattern, with closely related species or similar sequences being no more likely to infect each other, and remains an unresolved enigma. Variation of the conformationally flexible regions may alter the thermodynamics of the conformational change, commonly referred to as the conformational conversion, which occurs in the pathogenic process of the mammalian prion protein. A conformational ensemble scenario is supported by the species barrier in prion disease and evidence that there are strains of pathogenic prion with different conformations within species. To study how conformational flexibility has evolved in the prion protein, an investigation was undertaken on the evolutionary dynamics of structurally disordered regions in the mammalian prion protein, non-mammalian prion protein that is not vulnerable to prion disease, and remote homologs Doppel and Shadoo. Structural disorder prediction analyzed in an evolutionary context revealed that the occurrence of increased or altered conformational flexibility in mammalian PrPs coincides with key events among PrP, Doppel, and Shadoo. Comparatively rapid evolutionary dynamics of conformational flexibility in the prion protein suggest that the species barrier is not a static phenomenon. A small number of amino acid substitutions can repopulate the conformational ensemble and have a disproportionately large effect on pathogenesis.     

Design of inhibitors of thymidylate kinase from Variola virus as new selective drugs against smallpox: part II

Abstract

Acknowledging the importance of studies toward the development of measures against terrorism and bioterrorism, this study aims to contribute to the design of new prototypes of potential drugs against smallpox. Based on a former study, nine synthetic feasible prototypes of selective inhibitors for thymidylate kinase from Variola virus (VarTMPK) were designed and submitted to molecular docking, molecular dynamics simulations and binding energy calculations. The compounds are simplifications of two more complex scaffolds, with a guanine connected to an amide or alcohol through a spacer containing ether and/or amide groups, formerly suggested as promising for the design of selective inhibitors of VarTMPK. Our study showed that, despite the structural simplifications, the compounds presented effective energy values in interactions with VarTMPK and HssTMPK and that the guanine could be replaced by a simpler imidazole ring linked to a –NH₂ group, without compromising the affinity for VarTMPK. It was also observed that a positive charge in the imidazole ring is important for the selectivity toward VarTMPK and that an amide group in the spacer does not contribute to selectivity. Finally, prototype 3 was pointed as the most promising to be synthesized and experimentally evaluated.

Communicated by Ramaswamy H. Sarma     

Depression in Medical School: The Influence of Morningness‐Eveningness

Medical students are at higher risk for depression, affecting not only their lives but also patient care. This article studied a population of medical students engaged in lecture‐based learning regarding the presence of depressive symptoms and its relation to morningness‐eveningness. Depressive symptoms were assessed by the Beck Depressive Inventory scale (BDI>10), and diurnal preference was assessed by the Horne & Östberg Morningness/Eveningness Questionnaire (MEQ). Family history of depression and involvement in regular physical activity were also investigated. A total of 161 students, 77 (47.8%) males, aged 19 to 30 yrs (22.1±2.1) living in a city close to the equator were evaluated. Fifty‐three individuals (32.9%) had depressive symptoms. Depressive individuals showed a trend to be female (p=0.07). Also, female gender showed a non‐significant shift toward morningness. Fifty‐eight (36.0%) subjects participated in regular physical activity. In 57 cases (35.4%), there was a history of depression in the family. Fifteen individuals (9.3%) were definitely evening type, 42 (26.1%) were moderately evening type, 44 (27.3%) were indifferent, 42 (26.1%) were moderately morning type, and 18 (11.2%) were definitely morning type. Family history of depression (OR=0.29, 95% CI=1.37–6.12) and sedentary life (OR=0.28, 95% CI=0.12–0.65) were associated with depressive symptoms. Eveningness was associated with depressive symptoms (OR=0.66, 95% CI=0.50–0.88), and this association remained significant after adjusting for the presence of familial depression and physical activity (OR=0.71, 95% CI=0.52–0.95). In conclusion, depressive symptoms are independently associated with “eveningness” in medical students. These results should be confirmed by future studies involving a larger number of subjects.