Subtropical Areas Research Articles

A simplified fatigue model for CFRP-strengthened RC beams under the coupling action of a hot–wet/saline environment and cyclic loading

Reinforced concrete (RC) structures in subtropical coastal areas are subjected to the combined influences of temperature, humidity, and salt exposure. Previous studies on the fatigue failure of fiber-reinforced polymer (FRP)-RC structures did not consider the coupling effect of the environment and loading. In this study, a simplified hot–wet/saline environmental fatigue model was developed to consider the linear influence of environmental parameters, including temperature, humidity, and salinity. Then, a closed environmental box was self-designed to provide the temperature–saline environment. By simulating a subtropical coastal environment with typical salinity levels (0, 3, and 5 wt% NaCl) and temperatures (10, 35, and 50 °C), fatigue tests were conducted on 38 typical carbon fiber-reinforced polymer–RC beams. In assessing the simplified model’s predictive accuracy, the average errors for estimating the fatigue limits and lives in the validation groups with or without saline conditions were 4.1 % and 33.7 %, respectively. The simplified model indicated that higher unit temperature and humidity similarly reduced the fatigue limit and that higher salinity decreased the fatigue limit by approximately 7.2 times greater than temperature or humidity. This research provides valuable insights into the strength design and life prediction of RC structures in the offshore or subsea regions of subtropical coastal areas.

Evaluation of in vitro anthelmintic activity of crude extract and synthesized green silver nanoparticles of the leaves of Mammea americana L.

One of the most severe parasite infections to ever plague animals, paramphistomosis is particularly devastating in tropical and subtropical areas and causes significant economic losses to the world's food industry and poor animal health. In the present study potency of the crude extract and green synthesized silver nanoparticles from fresh and matureMammea americanaL.leaves was evaluated on trematodeParamphistomum cervi, collected from the infected rumen of the cow(Bos indicus) in 0.9% phosphate-buffered saline (PBS). The crude extract at five dose levels (1mL, 2mL, 3mL 4mL, and 5ml), and silver nanoparticles (AgNps) at the five dose levels (10mg/mL, 30mg/mL, 50mg/mL, 70 and 90mg/mL) were applied. The synthesized AgNPs were characterized using UV-VIS spectrophotometry, X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and Fourier Transform Infrared Spectroscopy (FTIR) analysis. Characterization studies of AgNPs revealed the synthesis of stable, crystalline AgNPs measuring an average size of 20-50nm. The efficacy was evaluated based on the spontaneous movement reduction and death ofP. cervi. Maximum anthelmintic activity was found at the dose of 5mL of crude extract and 90mg/mL of AgNPs ofM. americanaleaves. The scanning electron micrograph study of treated helminths of crude and AgNps revealed conspicuous distortion on the surface architecture. It also showed shrinkage of the whole body and severe damage on both suckers (anterior and posterior). AgNPs caused more shredded and torn tegumental surfaces with loss of tegumental papillae compared to untreated. Thus, this study confirmed that theM. americanaleaves extract and synthesized AgNPs can be a potential alternative herbal drug in traditional folklore medicine against serious helminth infections in our livestock industry.

Phylogenetic Diversity, Host Specificity, and Distribution of the Wood-Decaying Fungus Phellinotus teixeirae in Western Colombia’s Seasonally Dry Tropical Forest

Phellinotus (Polyporales) is a common genus of wood-decay fungi in tropical and subtropical areas, endemic to the Seasonally Dry Tropical Forest (SDTF) biome. However, Phellinotus diversity remains unexplored, despite being a major threat to living trees. Therefore, this study is aimed at confirming and characterizing through morphological and molecular data the first isolates of Phellinotus teixeirae in Pithecellobium dulce (Fabaceae) trees (locally referred to as ‘Chiminango’) from the endangered Colombian SDTF biome. Fifteen fungal specimens were recovered from living P. dulce trees, in the urban area and at the Universidad del Valle campus, and classified as P. teixeirae based on taxonomical descriptors. Phylogenetic relationships were inferred from a four-loci dataset (ribosomal and gene-coding regions), including 82 taxa covering 3991 nucleotide positions. The analysis recovered seven highly supported (>90% bootstrapping) monophyletic taxa of the ‘Phellinotus Clade’, and confirmed the new distribution range of P. teixeirae (100% bootstrap support), which extends approx. 1000 km north in the Neotropics. Hierarchical stratified Analysis of MOlecular VAriance (AMOVA) provided a clear genetic distinction between species (70% of variation, p-value = 0.001) and low differentiation among country of origin within species (11%, p-value = 0.044). Discriminant Analysis for Principal Components (DAPC) indicated complex clustering including closely related species, probably a signal of recent radiation and weak species boundaries. Median-joining haplotype network analysis identified unique haplotypes, which may correlate with new host colonization and population expansion (Tajima’s D ≤ −0.5). In conclusion, this study provides the first assessment of the genetic diversity of P. teixeirae in a novel geography (SDTP) and host tree (P. dulce). However, increasing the number of isolates remains critical to understand further the genus’ distribution patterns and drivers of genetic diversity.

Dengue Virus Surveillance in Nepal Yields the First On-Site Whole Genome Sequences of Isolates from the 2022 Outbreak.

The 4 serotypes of dengue virus (DENV1-4) can each cause potentially deadly dengue disease, and are spreading globally from tropical and subtropical areas to more temperate ones. Nepal provides a microcosm of this global phenomenon, having met each of these grim benchmarks. To better understand DENV transmission dynamics and spread into new areas, we chose to study dengue in Nepal and, in so doing, to build the onsite infrastructure needed to manage future, larger studies. During the 2022 dengue season, we enrolled 384 patients presenting at a hospital in Kathmandu with dengue-like symptoms; 79% of the study participants had active or recent DENV infection (NS1 antigen and IgM). To identify circulating serotypes, we screened serum from 50 of the NS1 + participants by RT-PCR and identified DENV1, 2, and 3 - with DENV1 and 3 codominant. We also performed whole-genome sequencing of DENV, for the first time in Nepal, using our new on-site capacity. Sequencing analysis demonstrated the DENV1 and 3 genomes clustered with sequences reported from India in 2019, and the DENV2 genome clustered with a sequence reported from China in 2018. These findings highlight DENV's geographic expansion from neighboring countries, identify China and India as the likely origin of the 2022 DENV cases in Nepal, and demonstrate the feasibility of building onsite capacity for more rapid genomic surveillance of circulating DENV. These ongoing efforts promise to protect populations in Nepal and beyond by informing the development and deployment of DENV drugs and vaccines in real time.

The Spatial Shifts and Vulnerability Assessment of Ecological Niches under Climate Change Scenarios for Betula luminifera, a Fast-Growing Precious Tree in China.

The spatial shifts and vulnerability assessments of ecological niches for trees will offer fresh perspectives for sustainable development and preservation of forests, particularly within the framework of rapid climate change. Betula luminifera is a fast-growing native timber plantation species in China, but the natural resources have been severely damaged. Here, a comprehensive habitat suitability model (including ten niche-based GIS modeling algorithms) was developed that integrates three types of environmental factors, namely, climatic, soil, and ultraviolet variables, to assess the species contemporary and future distribution of suitable habitats across China. Our results suggest that the habitats of B. luminifera generally occur in subtropical areas (about 1.52 × 106 km2). However, the growth of B. luminifera is profoundly shaped by the nuances of its local environment, the most reasonable niche spaces are only 1.15 × 106 km2 when limiting ecological factors (soil and ultraviolet) are considered, generally considered as the core production region. Furthermore, it is anticipated that species-suitable habitats will decrease by 10 and 8% with climate change in the 2050s and 2070s, respectively. Our study provided a clear understanding of species-suitable habitat distribution and identified the reasons why other niche spaces are unsuitable in the future, which can warn against artificial cultivation and conservation planning.

Strategic control of the cattle tick Rhipicephlaus microplus applied to rotational and silvopastoral grazing systems in subtropical areas.

This work evaluated if strategic control based on no more than three or four annual treatments is useful to control Rhipicephalus microplus infestations on cattle when it is applied to intensive rotational grazing and silvopastoral systems with high stocking rates in subtropical areas. In the intensive rotational grazing system, three annual treatments with chemical acaricides were applied on cattle in two different schemes: between spring and early summer and from late winter and late spring. Strategic control based on three treatments with chemical acaricides from late winter to late spring plus an additional fourth treatment in summer was tested in the silvopastoral system. In the intensive rotational grazing systems, the control schemes allow to reach a significant reduction in the tick load on cattle considering a time interval from spring to autumn. However, the efficacy levels were not high enough in some specific moments, namely, the tick counts of summer and autumn (there were not significant differences between treated and control groups). The scheme evaluated in the silvopastoral grazing system yielded better results than those tested for the intensive rotational system, because significant differences in tick load between treated and control groups were observed in all post-treatment counts and when the analysis was performed for the whole study period. However, values of efficacy in the count-by-count comparison were disparate, ranging from 64.1 to 99.7. Although the efficacy values obtained in the silvopastoral system were better than those of the rotational grazing systems, the total tick load on treated cattle in autumn was not low enough (mean abundance values 25.14 and 38.14). Ticks were more evenly distributed among hosts in late summer and autumn than in spring or early summer, where few hosts carry most of the ticks. Some management strategies as intensive rotational systems or silvopastoral structures can lead to a more efficient forage use, but they imply greater tick challenge than in extensive grazing systems. In these situations, the schemes of strategic control bases on three or four annual treatments should be complemented with additional tactical treatments in late summer or autumn.

Malaria cell identification using improved machine learning and modified deep learning architecture

Malaria continues to be a serious problem for public health because of its occurrence in tropical and subtropical areas with inadequate healthcare systems and few resources. For prompt intervention and treatment of malaria, effective and precise diagnosis is essential. Professional pathologists examine blood smear films by hand to get a microscopic diagnosis and another way they will do a rapid antigen malaria test which produces the result of 50% accuracy. Convolutional neural network (CNN) is a type of deep learning (DL) model that has been effectively used for a variety of image recognition applications. Our suggested approach uses, improved machine learning (IML) methods like support vector machine (SVM)+principal component analysis (PCA) fit, SVM+t-distributed stochastic neighbor embedding (t-SNE) fit, and CNN architecture with an accuracy of 86.23%, 88.27%, and 97.16% accuracy respectively, to combine feature extraction, data augmentation, and modify the layers by including the SVM algorithm in the final layer of the CNN architecture. The proposed method will significantly reduce pathologists' burden by automating the identification of malaria and improving diagnosis accuracy in resourceconstrained contexts

Community assembly of ectomycorrhizal fungal communities in pure and mixed Pinus massoniana forests

Ectomycorrhizal (EcM) fungi play an important role in nutrient cycling and community ecological dynamics and are widely acknowledged as important components of forest ecosystems. However, little information is available regarding EcM fungal community structure or the possible relationship between EcM fungi, soil properties, and forestry activities in Pinus massoniana forests. In this study, we evaluated soil properties, extracellular enzyme activities, and fungal diversity and community composition in root and soil samples from pure Pinus massoniana natural forests, pure P. massoniana plantations, and P. massoniana and Liquidambar gracilipes mixed forests. The mixed forest showed the highest EcM fungal diversity in both root and bulk soil samples. Community composition and co-occurrence network structures differed significantly between forest types. Variation in the EcM fungal community was significantly correlated with the activities of β-glucuronidase and β−1,4-N-acetylglucosaminidase, whereas non-EcM fungal community characteristics were significantly correlated with β-1,4-glucosidase and β-glucuronidase activities. Furthermore, stochastic processes predominantly drove the assembly of both EcM and non-EcM fungal communities, while deterministic processes exerted greater influence on soil fungal communities in mixed forests compared to pure forests. Our findings may inform a deeper understanding of how the assembly processes and environmental roles of subterranean fungal communities differ between mixed and pure plantations and may provide insights for how to promote forest sustainability in subtropical areas.

Feasibility and Techno-Economic Assessment of a 128kWp Grid-Tied SPV System using HOMER Pro

Abstract A substantial amount of the world’s annual CO2 emissions are attributable to the continued consumption of electricity from the grid that is generated from burning fossil fuels. Renewable energy sources could strengthen grid reliability and lessen their effect on the environment, especially in high-demand regions prone to power failures. Investigating the viability of erecting solar power plants in a subtropical area to provide the necessary electricity for an educational building that operates mainly during daylight hours is the main intent of the present study. The purpose of this investigation is to demonstrate and validate a model for enormous-scale commercial HRES applications (such as an educational institution) utilising the HOMER programme to figure out the optimal size. Minimising emissions of carbon dioxide, the main greenhouse gas responsible for accelerating global warming, is also of the utmost importance. Based on the simulation findings, the optimal system configuration consisted of a 120 kW converter and 400 PV arrays (each with 320 Wp = 128 kWp). For regional power generation, the most cost-effective choice is still a combination of solar panels and the grid. Findings show that a HRES can be economically feasible for installation in educational institutions at an initial capital cost of USD $0.068 million with annual operating expenses of USD $0.0447 million—a reduction of 44.11% compared to the existing system. The expected payback for this endeavour is five years. Other locations with identical climates could benefit from these results when considering the deployment of comparable technology. In order to help achieve a zero-carbon target, financial rewards could encourage governments to adopt similar schemes.

Foraging behavior and the nest architecture of a high-Andean stingless bee (Hymenoptera: Apidae: Meliponini) revealed by X-ray computerized tomography

Stingless bees (Hymenoptera: Apidae: Meliponini) are key pollinators of both cultivated and wild plants in tropical and subtropical areas of the world. While most species are found in lowland to mid-elevations, a few have adapted to high elevations, and their biology remains poorly understood. We assess the foraging pattern of Parapartamona zonata (Smith) in the central Andes of Colombia (2583 m.a.s.l.) and apply computer tomography to visualize and characterize its internal nest architecture. Bees foraged for pollen and nesting materials (resin and/or mud) from sunrise (5:40 h) to sunset (17:45), even at ambient temperatures as low as 11 °C. Foraging varied significantly throughout the day and temperature and sky condition explained 47% of its variance. Differences in the nest architecture, when compared with previous records, suggest that nesting behavior might be variable. These results are discussed in the context of behavioral adaptations in this unique environmental niche.

Studies of the Carbohydrates Content in Tissues of Hamster (Mesocricetus Auratus) Infected with Hookworm (Ancylostoma Ceylanicum)

Hookworm infections are the helminthic infection that affects tropical and subtropical areas. Several laboratory animals have been infected with hookworms. Due to parasitic infection, the structure and function of tissues undergo severe derangements and metabolic disorders. In the present study, a hamster, Mesocricetus auratus was infected with a hookworm, Ancylostoma ceylanicum. Investigation of the Carbohydrate content of A.ceylanicum in M. auratus was studied in control and infected ones. Understanding the level of pathogenicity caused by an A. ceylanicum infection can be aided by examining the total amount of carbohydrates present in the tissues of the host, M. auratus. A biochemical estimation of the total carbohydrate content was made. The brain and spleen were found to have higher carbohydrate contents. There was decreased carbohydrate activity in the kidney, liver, gut, and muscle. The present study depicted the alterations in the total carbohydrate content in various tissues of the host, M. auratus due to the infection of A. ceylanicum. The result of the data obtained in the various tissues due to infection was found to be statistically significant. It was further plotted graphically plotted and interpreted. The research work done in the present study helped to understand the biochemical changes taking place in the host, Mesocricetus auratus due to hookworm, Ancylostoma ceylanicum infection.

Spatiotemporal Distribution Characteristics and Influencing Factors of Dissolved Potentially Toxic Elements along Guangdong Coastal Water, South China

In this study, five potentially toxic elements (PTEs) (Hg, Pb, As, Zn, and Cu) and five physicochemical factors (pH, dissolved oxygen, salinity, chlorophyll a, and chemical oxygen demand) relating to surface seawater were measured along the coast of Guangdong Province (GD), China, during three seasons in 2019. Comprehensive analyses were conducted to explore the distribution characteristics, pollution degrees, and influencing factors of PTE. The results showed that the concentrations of PTE varied spatially and seasonally due to these elements’ complex sources and behaviors. Pb was the most abundant toxic element, reaching considerable contamination levels. Overall, the average pollution degrees of Cu, As, and Zn were higher around the east coast of GD, while Hg and Pb levels were higher in the west coast region of GD. The correlation analysis showed that the variation of different physicochemical parameters had different degrees of influence on PTE transport and transformation. This study can help environmental managers gain deeper insight into the influence of complex factors on PTE and improve the efficiency of pollution control in this significant subtropical coastal area.

Coriolopsis strumosa as an Orchid Endophytic Fungus and Its Spatial Distribution in Epidendrum sp. (Orchidaceae).

Coriolopsis spp. are wood-decaying fungi that inhabit forests. They are mainly distributed in tropical and subtropical areas. Strain Epi910 was isolated from the asymbiotically germinated protocorm of Epidendrum sp. and identified as Coriolopsis strumosa. Symbiotic germination and high-throughput sequencing of the endophytic fungal communities of different parts were performed to characterize the function and spatial distribution of the Epi910 isolate. Under symbiotic germination, Epi910 promoted seed germination and seedling formation as an endophytic native fungus of Epidendrum sp. Endophytic fungal communities from seven different parts of Epidendrum sp. were characterized. In total, 645 OTUs were identified; 30 OTUs were shared among all seven parts. The internal transcribed spacer sequence of Epi910 was identical to that of a dominant shared OTU (OTU6). The relative abundance of OTU6 in the seven parts was identified as follows: capsule pericarp > seed > root > asymbiotically germinated protocorm > epiphytic root > ovary > rachis. Our results suggest that the isolate belonging to Coriolopsis strumosa could promote the germination of Epidendrum sp. There may, therefore, be endophytic fungi other than common orchid mycorrhizal fungi with the ability to enhance germination in orchids.

Farmers’ Adoption, Knowledge, and Perceptions of Tick Control Measures on Dairy Farms in Subtropical Areas of Continental Ecuador

The application of tick control strategies on tropical dairy cattle strongly relies on farmers’ uptake, knowledge, and perceptions of the efficacy of control measures. This study aims to identify common and uncommon tick control practices employed by dairy farmers in subtropical areas of Ecuador and associate them with the presence of infestation and acaricide resistance. Data were collected through a cross-sectional survey and participatory meetings. Multiple correspondence analysis was used to explore the association between management variables and the level of tick infestation and resistance. It was determined that the main method of acaricide control is still chemical, mainly using spray baths. Generally, when this form of application is used, acaricides are overdosed, in contrast to the pour-on method with underdosage. Among the measures farmers adopt when chemical treatment has failed is to use overdoses of products, mix different acaricides, and use focused treatments (wipe cloth) with irritant substances. The absence of a high level of infestation was related to acaricide dips every 3–4 weeks and the use of intensive grazing. On the other hand, the high infestation was related to the use of organophosphates, wipe cloth application, and the report of tick-borne diseases (TBDs). A small group of farmers have good knowledge and seek alternatives to chemical control, experimenting with biological controls, herbal extracts, manual tick removal, and paddock control. Additionally, farmers reported the presence of TBDs (47%) and the presence of animals poisoned by acaricides (6%), which died in 75% of those cases. Farmers frequently mentioned that tick infestation induces milk drop production and weight loss and is associated with the presence of TBDs. This information is crucial to improve tick control management in Ecuador, particularly through implementing practices that mitigate resistance to acaricides and ensure long-term solutions that help maintain the efficacy of tick control treatments.

Characterization of Argonaute-containing protein complexes in Leishmania-infected human macrophages.

The intracellular protozoan parasite Leishmania causes leishmaniasis in humans, leading to serious illness and death in tropical and subtropical areas worldwide. Unfortunately, due to the unavailability of approved vaccines for humans and the limited efficacy of available drugs, leishmaniasis is on the rise. A comprehensive understanding of host-pathogen interactions at the molecular level could pave the way to counter leishmaniasis. There is growing evidence that several intracellular pathogens target RNA interference (RNAi) pathways in host cells to facilitate their persistence. The core elements of the RNAi system are complexes of Argonaute (Ago) proteins with small non-coding RNAs, also known as RNA-induced silencing complexes (RISCs). Recently, we have shown that Leishmania modulates Ago1 protein of host macrophages for its survival. In this study, we biochemically characterize the Ago proteins' interactome in Leishmania-infected macrophages compared to non-infected cells. For this, a quantitative proteomic approach using stable isotope labelling by amino acids in cell culture (SILAC) was employed, followed by purification of host Ago-complexes using a short TNRC6 protein-derived peptide fused to glutathione S-transferase beads as an affinity matrix. Proteomic-based detailed biochemical analysis revealed Leishmania modulated host macrophage RISC composition during infection. This analysis identified 51 Ago-interacting proteins with a broad range of biological activities. Strikingly, Leishmania proteins were detected as part of host Ago-containing complexes in infected cells. Our results present the first report of comprehensive quantitative proteomics of Ago-containing complexes isolated from Leishmania-infected macrophages and suggest targeting the effector complex of host RNAi machinery. Additionally, these results expand knowledge of RISC in the context of host-pathogen interactions in parasitology in general.

Seasonal hypoxia enhances sediment iron-bound phosphorus release in a subtropical river reservoir

Dams worldwide commonly accelerate the eutrophication of reservoirs. While the seasonal hypoxia in deep reservoirs is widely acknowledged, there is limited research on its impact on benthic phosphorus (P) cycling and P fraction release from the reservoir sediments. Here we show that seasonal hypoxia enhances sediment P release and P fluxes at the sediment-water interface (SWI) which might alter P dynamics in deep reservoirs. We conducted a detailed measurement of sediment P fractions through the SEDEX approach, combined with a labile P gradient analysis using the diffusive gradients in thin films (DGT) technique to understand P cycling patterns in sediments during the transition period from spring (oxic) to late summer (hypoxic) conditions. The sediment P pool was predominantly composed of iron-bound phosphorus (Fe−P, 76–80 %), primarily due to the widespread occurrence of lateritic red soil (rich in Fe2O3/MnO2) in subtropical areas. More organic-P was observed in summer compared to spring. A significant increase in labile P occurred at the depth of 0–4 cm and 0–1 cm in spring and summer, respectively, where sediment P release was primarily governed by the reduction of Fe−P and the generation of S2−. A higher apparent fluxes of phosphate across the SWI were observed in summer characterized by higher temperature and lower oxygen levels. The current results suggest that seasonal hypoxia was a crucial factor affecting P cycling and diffusion in deep reservoirs. These findings present important implications for the ecology and management of the watershed-coast ecosystem.

A Review on Chemical Constituents and Pharmacological Action of the Genus Lindera

The genus Lindera consists of approximately 100 species that are widely distributed in tropical and subtropical areas throughout the world. It is represented by widely well-known medicinal and aromatic plants that produce various phytochemicals with potential pharmacological actions. This review attempts to summarize the information on the phytochemicals of Lindera species together with their biological properties. The data and information were collected via an electronic search engine which are Scopus, ScienceDirect, Google Scholar, PubMed, and SciFinder. Sesquiterpenes represent the major chemical compounds that have been characterised in Lindera species, as well as alkaloids, flavonoids, and phenolics. These compounds were shown to possess anticancer, antifibrotic, anti-inflammatory, antitumor, antioxidant, anti-arthritic, cytotoxic, antiallergic, and antihyperlipidemic properties. The outcome of these studies will further support the therapeutic potential of the genus Lindera and provide convincing evidence for its future clinical applications in modern medicine.

Old Pinus massoniana forests benefit more from recent rapid warming in humid subtropical areas of central-southern China

Trees progress through various growth stages, each marked by specific responses and adaptation strategies to environmental conditions. Despite the importance of age-related growth responses on overall forest health and management policies, limited knowledge exists regarding age-related effects on dendroclimatic relationships in key subtropical tree species. In this study, we employed a dendrochronological method to examine the impact of rapid warming on growth dynamics and climatic sensitivity of young (40–60 years) and old (100–180 years) Pinus massoniana forests across six sites in central-southern China. The normalized log basal area increment of trees in both age groups increased significantly following rapid warming in 1984. Trees in young forests further showed a distinct growth decline during a prolonged severe drought (2004–2013), whereas those in old forests maintained growth increases. Tree growth was more strongly influenced by temperature than by moisture, particularly in old forests. Spring temperatures strongly and positively impacted the growth of old trees but had a weaker effect on young ones. Old forests had a significantly lower resistance to extreme drought but faster recovery compared to young forests. The “divergence problem” was more pronounced in younger forests due to their heightened sensitivity to warming-induced drought and heat stress. With ongoing warming, young forests also may initially experience a growth decline due to their heightened sensitivity to winter drought. Our findings underscore the importance of considering age-dependent changes in forest/tree growth response to warming in subtropical forest management, particularly in the context of achieving “Carbon Peak & Carbon Neutrality” goals in China.

Targeting Trypanothione Metabolism in Trypanosomatids.

Infectious diseases caused by trypanosomatids, including African trypanosomiasis (sleeping sickness), Chagas disease, and different forms of leishmaniasis, are Neglected Tropical Diseases affecting millions of people worldwide, mainly in vulnerable territories of tropical and subtropical areas. In general, current treatments against these diseases are old-fashioned, showing adverse effects and loss of efficacy due to misuse or overuse, thus leading to the emergence of resistance. For these reasons, searching for new antitrypanosomatid drugs has become an urgent necessity, and different metabolic pathways have been studied as potential drug targets against these parasites. Considering that trypanosomatids possess a unique redox pathway based on the trypanothione molecule absent in the mammalian host, the key enzymes involved in trypanothione metabolism, trypanothione reductase and trypanothione synthetase, have been studied in detail as druggable targets. In this review, we summarize some of the recent findings on the molecules inhibiting these two essential enzymes for Trypanosoma and Leishmania viability.

Projected habitat preferences of commercial fish under different scenarios of climate change

The challenges of commercial species with the threats of climate change make it necessary to predict the changes in the distributional shifts and habitat preferences of the species under possible future scenarios. We aim to demonstrate how future climatic changes will affect the habitat suitability of three species of commercial fish using the predictive technique MaxEnt. The dataset used to extract geographical records included OBIS (54%), GBIF (1%), and literature (45%). The output of the model indicated accurate projections of MaxEnt (AUC above 0.9). Temperature was the main descriptor responsible for the main effects on the distribution of commercial fish. With increasing RCP from 2.5 to 8.5, the species would prefer saltier, higher temperatures and deeper waters in the future. We observed different percentages of suitable habitats between species during RCPs showing distinct sensitivity of each fish in facing climate changes. Negative effects from climate change on the distribution patterns of commercial fish were predicted to lead to varying degrees of reduction and changes of suitable habitats and movement of species towards higher latitudes. The finding emphasizes to implement adaptive management measures to preserve the stocks of these commercial fish considering that the intensification of the effects of climate change on subtropical areas and overexploited species is predicted.