Semiarid Region Of Northeastern Brazil Research Articles

Update on the geographical distribution of freshwater crabs of the Pseudothelphusidae family in the semi-arid region of northeastern Brazil

The humid forest zones of northeastern Brazil are recognized as endemic hotspots for pseudothelphusid crabs. In this study, we report new occurrence records of the pseudothelphusids, Fredius ibiapaba and Kingsleya attenboroughi, in humid soil and streams within humid forests of the semi-arid region of northeastern Brazil. These new records expand the geographical distribution of these crabs, highlighting their potential to inhabit humid forests throughout this region. Furthermore, this information indicates that these crabs, especially K. attenboroughi, are not confined to slopes and patches of humid forests in highland swamps but can also extend to springs in other areas of the Brazilian semi-arid region.

Antivenom potential of the latex of Jatropha mutabilis baill. (Euphorbiaceae) against Tityus stigmurus venom: Evaluating its ability to neutralize toxins and local effects in mice

Ethnopharmacological relevanceSpecies of the Jatropha genus (Euphorbiaceae) are used indiscriminately in traditional medicine to treat accidents involving venomous animals. Jatropha mutabilis Baill., popularly known as “pinhão-de-seda,” is found in the semi-arid region of Northeastern Brazil. It is widely used as a vermifuge, depurative, laxative, and antivenom. Aim of the studyObtaining the phytochemical profile of the latex of Jatropha mutabilis (JmLa) and evaluate its acute oral toxicity and inhibitory effects against the venom of the scorpion Tityus stigmurus (TstiV). Materials and methodsThe latex of J. mutabilis (JmLa) was obtained through in situ incisions in the stem and characterized using HPLC-ESI-QToF-MS. Acute oral toxicity was investigated in mice. The protein profile of T. stigmurus venom was obtained by electrophoresis. The ability of latex to interact with venom components (TstiV) was assessed using SDS-PAGE, UV–Vis scanning spectrum, and the neutralization of fibrinogenolytic and hyaluronidase activities. Additionally, the latex was evaluated in vivo for its ability to inhibit local edematogenic and nociceptive effects induced by the venom. ResultsThe phytochemical profile of the latex revealed the presence of 75 compounds, including cyclic peptides, glycosides, phenolic compounds, alkaloids, coumarins, and terpenoids, among others. No signs of acute toxicity were observed at a dose of 2000 mg/kg (p.o.). The latex interacted with the protein profile of TstiV, inhibiting the venom's fibrinogenolytic and hyaluronidase activities by 100%. Additionally, the latex was able to mitigate local envenomation effects, reducing nociception by up to 56.5% and edema by up to 50% compared to the negative control group. ConclusionsThe latex of Jatropha mutabilis exhibits a diverse phytochemical composition, containing numerous classes of metabolites. It does not present acute toxic effects in mice and has the ability to inhibit the enzymatic effects of Tityus stigmurus venom in vitro. Additionally, it reduces nociception and edema in vivo. These findings corroborate popular reports regarding the antivenom activity of this plant and indicate that the latex has potential for treating scorpionism.

Critical thermal maxima in neotropical ants at colony, population, and community levels.

Global warming is exposing many organisms to severe thermal conditions and is having impacts at multiple levels of biological organisation, from individuals to species and beyond. Biotic and abiotic factors can influence organismal thermal tolerance, shaping responses to climate change. In eusocial ants, thermal tolerance can be measured at the colony level (among workers within colonies), the population level (among colonies within species), and the community level (among species). We analysed critical thermal maxima (CTmax) across these three levels for ants in a semiarid region of northeastern Brazil. We examined the individual and combined effects of phylogeny, body size (BS), and nesting microhabitat on community-level CTmax and the individual effects of BS on population- and colony-level CTmax. We sampled 1864 workers from 99 ant colonies across 47 species, for which we characterised CTmax, nesting microhabitat, BS, and phylogenetic history. Among species, CTmax ranged from 39.3 to 49.7°C, and community-level differences were best explained by phylogeny and BS. For more than half of the species, CTmax differed significantly among colonies in a way that was not explained by BS. Notably, there was almost as much variability in CTmax within colonies as within the entire community. Monomorphic and polymorphic species exhibited similar levels of CTmax variability within colonies, a pattern not always explained by BS. This vital intra- and inter-colony variability in thermal tolerance is likely allows tropical ant species to better cope with climate change. Our results underscore why ecological research must examine multiple levels of biological organisation.

Economics of small-scale aquaculture farms in Brazilian Northeastern semi-arid region: Characteristics, feasibility, and profitability models

Inland aquaculture represents a significant component of the aquaculture sector in Brazil. This activity is present in all Brazilian regions, yet the economic feasibility and the relationship between their productive variables and profitability indices remain poorly accessed in Brazil's semi-arid regions. This study aims to characterise, assess the economic feasibility, and evaluate the relationship between productive variables and profitability indices in the aquaculture sector in Feira Nova (Northeast Brazil). The data was collected through interviews with all producers in Feira Nova city and modelled using the software R. The aquaculture sector in Feira Nova is predominantly small-scale and encompasses a wide range of production strategies for shrimp and fish cultures, with profitable outcomes. The models demonstrated that economic and management variables were more closely associated with profitability indices than farm characteristics such as farm size. Feira Nova's profitability indices reinforces the small-scale aquaculture as a promising activity to alleviate poverty and generate wealth in Brazil semi-arid regions. However, governance improvements are necessary to boost the development of inland aquaculture in the country.

Evaluating Daily Water Stress Index (DWSI) Using Thermal Imaging of Neem Tree Canopies under Bare Soil and Mulching Conditions

Water stress on crops can severely disrupt crop growth and reduce yields, requiring the accurate and prompt diagnosis of crop water stress, especially in semiarid regions. Infrared thermal imaging cameras are effective tools to monitor the spatial distribution of canopy temperature (Tc), which is the basis of the daily water stress index (DWSI) calculation. This research aimed to evaluate the variability of plant water stress under different soil cover conditions through geostatistical techniques, using detailed thermographic images of Neem canopies in the Brazilian northeastern semiarid region. Two experimental plots were established with Neem cropped under mulch and bare soil conditions. Thermal images of the leaves were taken with a portable thermographic camera and processed using Python language and the OpenCV database. The application of the geostatistical technique enabled stress indicator mapping at the leaf scale, with the spherical and exponential models providing the best fit for both soil cover conditions. The results showed that the highest levels of water stress were observed during the months with the highest air temperatures and no rainfall, especially at the apex of the leaf and close to the central veins, due to a negative water balance. Even under extreme drought conditions, mulching reduced Neem physiological water stress, leading to lower plant water stress, associated with a higher soil moisture content and a negative skewness of temperature distribution. Regarding the mapping of the stress index, the sequential Gaussian simulation method reduced the temperature uncertainty and the variation on the leaf surface. Our findings highlight that mapping the Water Stress Index offers a robust framework to precisely detect stress for agricultural management, as well as soil cover management in semiarid regions. These findings underscore the impact of meteorological and planting conditions on leaf temperature and baseline water stress, which can be valuable for regional water resource managers in diagnosing crop water status more accurately.

Chemical Composition, Antifungal Activity and Toxicological Evaluation of Lippia sidoides Cham.

Candida species are normally commensal yeasts residing in the human body, under certain circumstances, can trigger pathological conditions such as candidiasis, not to mention antifungal resistance. Lippia sidoides Cham., or pepper-rosmarinus, is a native plant found in the Northeastern semi-arid region of Brazil, cited in ethnobotanical studies for its bioactive potential. This approach aims not only to expand the understanding of the antifungal efficacy of the ethanol extract of L. sidoides (EELs) but also to evaluate synergies that may enhance the available therapeutic arsenal, using the checkerboard method, and to assess potential toxic effects of this extract using model organisms, Artemia salina and Drosophila melanogaster, to evaluate mortality rates. Antifungal activity was observed at high concentrations (>1024 μg/mL) for both strains of Candida albicans and Candida krusei tested, with the most significant inhibition of fungal growth when the compound was used in synergy with fluconazole at 8.0 and 128 μg/mL, respectively. This activity likely occurred due to the interaction between the chemical composition of the ethanol extract rich in flavonoids and tannins with the reference drug. Regarding toxicity, both in relation to D. melanogaster and A. salina, no toxic results were observed at low concentrations. These results suggest that the ethanol extract of EELs may be a potential alternative as an adjuvant to fluconazole in the treatment of fungal infections caused by Candida spp. The observed synergy suggests that this combination may help overcome resistance to conventional antifungals and improve treatment efficacy.

Autecology of the gecko Phyllopezus periosus (Squamata: Phyllodactylidae) inhabiting rock cliffs of a waterfall canyon from the semi-arid region of northeastern Brazil

Phyllopezus periosus is the largest phyllodactilid in Brazil, with a relictual distribution in the Caatinga Domain. Herein, we investigated the autecology of P. periosus, describing activity patterns, microhabitat use (spatial niche dimension), foraging mode, body temperature, reproduction, diet (trophic niche dimension), and temperature. Also, we tested the influence of seasonality and ontogeny on these biological aspects. Geckos (n = 116, 54 females, 33 males, and 29 juveniles) were sampled from October 2013 to September 2014. Phyllopezus periosus has an unimodal activity pattern, with peak activity in the early hours of the night. Males are more robust than females, and forelimbs in females are longer than in males. The body temperatures of this thermoconformer gecko are higher in the dry season. The reproductive season begins in the early dry season, with a fixed clutch of two eggs. Although we did not find evidence of more than one clutch per year, the studied population of P. periosus reproduces for an extended period throughout the dry season, as highlighted by the presence of juveniles all year. Phyllopezus periosus is saxicolous and presents a generalist diet composed mainly of arthropods, also including vertebrates such as frogs and lizards.

Effects of the latest drought on the alluvial aquifer of a semiarid region in northeastern Brazil

Effects of the latest drought on the alluvial aquifer of a semiarid region in northeastern Brazil

Exposure of small ruminants and humans to Coxiella burnetii in the semi-arid region of Northeastern Brazil.

Q fever is a zoonotic disease caused by the obligate intracellular pathogen Coxiella burnetii, for which domestic ruminants are the primary source of infection in humans. Herein, we investigated the presence of C. burnetii in humans, sheep, and goats in the semi-arid region of northeastern Brazil. The presence of anti-C. burnetii antibodies was surveyed using indirect immunofluorescence assay, and detection of C. burnetii DNA was performed by polymerase chain reaction (PCR). Anti-C. burnetii antibodies were detected in 60% of farms, 4.8% of goats, 1.5% of sheep, and 4.5% of human samples. PCR was positive in 18.9% of blood samples, 7.7% of milk samples, and 7.7% of vaginal mucus samples. A DNA sequence of a C. burnetii DNA sample extracted from the goat vaginal mucus showed 99.2-99.4% nucleotide identity with other strains previously reported in Brazil. These results indicate that C. burnetii is present in the surveyed area, where it poses a risk to both public and animal health. These findings indicate an urgent need for educative actions to protect population, as well as better training of veterinarians to detect and report Q fever.

Exploring the Therapeutic Potential of Amburana cearensis: A Scientometric Study on an Endangered Medicinal Tree

Amburana cearensis (Fabaceae) is a native tree of the Brazilian northeastern semiarid region, which has considerable economic, medicinal, and social importance, especially in the Caatinga biome. This study aims to identify the scientific knowledge generated about the pharmacological applicability of the species. We analyzed scientific works on the widespread pharmacological use of A. cearensis, adopting the scientometric research method. The medicinal properties were classified according to the uses mentioned in the manuscripts, considering body systems and treated symptoms. They were associated with the International Classification of Diseases and Related Health. We identified a total of 86 articles addressing the medicinal potential of the species, distributed in 57 journals published between 2005 and 2023. There was a significant increase in publications during the period evaluated. Also, the species has been widely used in traditional medicine, which has attracted new studies, especially experimental ones focusing on unraveling its pharmacological potential. One trend observed was a significant geographic bias, since most of the studies investigated were carried out by researchers linked to Brazilian institutions located mainly in the northeast. This region includes the largest number of species occurrence points, explaining the interest of these institutions in recognizing the biological potential of their local or regional flora. In-depth investigations into the medicinal properties and secondary metabolites produced by A. cearensis should continue so that its therapeutic benefits are fully understood. However, it is necessary to link research into chemical and pharmacological properties with consideration of the importance of sustainable management of the species, since it faces risks of extinction. We acknowledge that an earlier version of this manuscript was presented as a dissertation by Ayane Emília Dantas dos Santos to fulfil the academic requirements for the degree of Forest Science at the Federal University of Rio Grande do Norte. The dissertation is available for reference at the following link: https://repositorio.ufrn.br/jspui/bitstream/123456789/46918/1/Cienciometriaetnobotanicamodelagem_Santos_2022.pdf.

Seed osmopriming with salicylic acid on induction of tolerance of Cenostigma pyramidale to water deficit

Cenostigma pyramidale is an endemic species of Brazil, widely spread in the Caatinga biome. The conditions in the semi-arid Northeastern region of Brazil can affect the development of plants due to the irregularity of rainfall, limiting the availability of water and reducing the germination and initial growth of native species. Therefore, seed priming with salicylic acid may mitigate the effects of water stress on plants. The objective of this work was to evaluate the effect of seed osmopriming with salicylic acid as a water deficit attenuator on germination and initial growth of C. pyramidale seedlings. A completely randomized design in a 5 × 5 factorial scheme, corresponding to five osmotic potentials (Ψs – 0, -0.3, -0.6, -0.9 and -1.2 MPa) and five doses of salicylic acid (0, 0.5, 1.0, 1.5 and 2.0 mM), with four repetitions of 25 seeds, was used. Germination and initial growth of C. pyramidale were compromised by water deficit. Osmopriming of seeds with salicylic acid at a dose of 0.63 mM is an efficient strategy to reduce the effect of water deficit in the germination stage from the potential of -0.2 MPa. The vigor of C. pyramidale seeds increased under deficit conditions with the application of salicylic acid, with the concentration varying from 0.5 to 1.0 mM. Osmopriming seeds with 0.87 mM salicylic acid promotes the development of vigorous seedlings under water deficit conditions.

Assessment of Soil Quality of Smallholder Agroecosystems in the Semiarid Region of Northeastern Brazil

The assessment of soil quality is crucial for the sustainable development of agriculture in semiarid regions. Due to their sensitivity to management practices, soil chemical and physical quality indicators are used for investigating soil quality. This study aimed to assess the soil quality of smallholder agroecosystems from the Brazilian semiarid region. Soil physical and chemical attributes were screened using principal component analysis (PCA) and integrated into a weighted additive soil quality index (SQI). Soil quality was obtained using linear and non-linear scoring methods, a total data set (TDS), and a minimum data set (MDS). The soil quality of the agroecosystems was designated as being of moderate grade. The MDS for soil quality assessment includes cation exchange capacity, C stock, exchangeable sodium percentage, flocculation degree, pH, electrical conductivity, available P, and K+ from twenty-five indicators of the TDS. This MDS mainly reflects the input of manure and crop residues associated with moderate weathering of easily weatherable minerals given the semiarid conditions. The SQI obtained can be used to synthesize the information of the TDS and is a valuable tool to indicate the soil quality of agroecosystems; thereby, it can be used with indicators of sustainable management for application at a regional scale.

Cutting of dry forests in a semiarid region of northeastern Brazil

Cutting of dry forests in a semiarid region of northeastern Brazil

Woody Species Richness and Precipitation as drivers of Primary Productivity in Dry Forests of Northeastern Brazil

Although it is common sense in the scientific community that there is a correlation between species richness and primary productivity, empirically this is poorly addressed for semiarid ecosystems. In the present study (1) we correlate woody species richnesswith a vegetation index from satellite data (as a proxy for primary productivity); we also determined (2) the effect of rainfall on productivity, and (3) rainfall and productivity anomaly indices for 49 sites in Dry Forests of Northeastern semiarid region of Brazil. We show that both species richness and rainfall are positively correlated with productivity (r² = 0,33 and p < 0,05;r² = 0,11, n = 49 and p < 0,05, n = 49; respectively). Productivity has a significant one month lag in response to rainfall (r2 = 0.39 ± 0.16; p < 0.001; n = 49). We also found that rainfall shows an anomaly 3 times more intense than the productivity anomaly (p < 0.001, r2 = 0.5). We conclude that at the regional level, woody species richness has a stronger effect than rainfall on productivity of Dry Forests of semiarid Brazil. In addition, the anomaly results showed the vegetation´s resistance to the semiarid harsh climate, an important result for conservation and policy under a climate change scenario.

Potassium fertigation and organic fertilisation in ‘Syrah’ grape in Northeastern Brazil: yield, must characteristics and phenolic compounds

The effect of both potassium and organic fertilisation on grape yield and must composition originating from wine grapevines cultivated in the São Francisco river basin, in the semi-arid region of Northeastern Brazil, is not well known. Since soils from that region usually have low organic matter content, we hypothesise that soil application of organic fertiliser and potassium application through drip irrigation enhances the availability of this nutrient in the soil, and it influences grape yield and quality. Hence, five doses of potassium (0, 20, 40, 80 and 160 kg ha-1) applied through a drip irrigation system and two doses of goat manure as organic fertiliser applied into the soil (0 and 7.5 m3 ha-1) after pruning were evaluated concerning yield and berry quality of grapevine ‘Syrah’ over four growing seasons (April 2013 to July 2015) in Petrolina, state of Pernambuco, Brazil. The experimental design was randomised blocks with 5 replications. We evaluated yield (t ha-1), weight of 100 berries (g), must volume (mL), total soluble solids (°Brix), pH and total titratable acidity (‰), K, Mg and Ca contents and phenolic compounds (total polyphenols, anthocyanins and flavonoids). The increasing application of potassium at the different doses of organic fertiliser did not alter the crop yield, except in the second season. Nonetheless, K concentration in grape must was influenced in the four growing seasons, with higher values at fitted K2O doses by polynomial regression of 83.62 kg ha-1 (first season), 101.25 kg ha-1 (second season), 120.00 kg ha-1 (third season) and 77.99 kg ha-1 (0 m3 ha-1 organic fertiliser) and 96.07 kg ha-1 (7.5 m3 ha-1 organic fertiliser) in the fourth season. The addition of increasing doses of potassium interfered with the wine grape quality, which is an important factor to be considered in relation to its acidity. Organic fertilisation did not affect the most quality characteristics of the grapes.

From molecules to ecosystems: Insights into a network of interactions for a Chagas disease outbreak using Triatoma brasiliensis as natural samplers

Exploring the dynamics of disease transmission involves an understanding of complex interactions within the eco-epidemiologic framework. In the context of Chagas disease (CD), elements are mainly represented by the interactions among the pathogen, insect vector, host, humans and the environment. We performed quantitative and qualitative analyses on a dataset derived from 98 Triatoma brasiliensis infected by trypanosomatids, which were linked to a CD outbreak in the semi-arid region of northeastern Brazil. We extracted invertebrate-derived DNA (iDNA) from these insects, comprising 18 populations around the outbreak area, each indicative of various strata of anthropogenic influence. Food source (FS) diversity, representing potential parasite reservoirs, was determined through mitochondrial gene (cyt b) sequencing of vertebrates, and parasite genotyping was accessed using fluorescent amplified fragment barcodes (FFLB) of trypanosomatids. We also assessed the residents' awareness of breeding sites for CD vectors in the inspected houses. The quantification of Trypanosoma cruzi was estimated via real-time PCR and is denominated here as the average parasite load (PL) per insect (T. cruzi/intestinal unit). We aimed to address vector-parasite-host-environment interactions that were discussed based on their significance among the components. Notably, among the significant interactions, we observed that the PL in the insects was significantly influenced by FS. Infected insects that fed on the classic reservoir, Didelphis albiventris, and Galea spixii exhibited higher PLs, compared to those that fed on Kerodon rupestris (p < 0.04)—a primary host. While D. albiventris is already recognized as a synanthropic species, we propose that G. spixii may also be undergoing a synanthropic process. Conversely, domestic cats are frequently identified as FS in infected insects from the sylvatic environment, suggesting a possible change in their behavior towards a wild state. Therefore, we propose that neglected anthropogenic actions have facilitated the reciprocal (sylvatic-peridomestic) circulation of T. cruzi—especially noted for TcI because it was predominant in insects found in peridomestic environments. Residents are often unaware of the existence of insect breeding grounds near their homes, particularly when it involves the storage of materials without planning for use, such as piles of tiles, bricks and wood. Although indirect inferences about the interaction among vector-parasite-host-environment are still incipient, we highlight the potential use of vectors as natural samplers of biological and ecological components in transmitting the disease.

Parasitism on domestic cats by Amblyomma auricularium and serological evidence of exposure to Rickettsia amblyommatis.

The domestic cat is not considered a primary host for any specific tick species; however, it can be affected by some Ixodidae species, such as Rhipicephalus sanguineus sensu lato and Amblyomma spp. The study reports parasitism by Amblyomma auricularium and the detection of anti-Rickettsia spp. antibodies in domestic cats from a rural property in the Afrânio municipality, Pernambuco, Brazil. Amblyomma auricularium (24 nymphs, six females, and four males) and Amblyomma sp. (42 larvae) parasitized three cats, and 73 free-living ticks were captured in armadillo burrows: A. auricularium (36 nymphs, six females, five males) and Amblyomma sp. (26 larvae). Blood samples from cats were collected and the obtained plasma were subjected to indirect immunofluorescence assay (IFA) to detect antibodies against Rickettsia antigens. Thus, anti-Rickettsia spp. antibodies were determined (titers ranging from 128 to 512) and showed a predominant antibody response to Rickettsia amblyommatis or a very closely related genotype. This study reports the first infestation of nymphs and adults of A. auricularium on cats in a new area of occurrence in the semi-arid region of Northeastern Brazil and reports for the first time the presence of anti-Ricketsia antibodies in cats in the region, with R. amblyommatis as the probable infectious agent.

Unveiling the unknown diversity of planktonic green algae (Chlorophyta) in urban ponds in the semiarid region of Northeastern Brazil

Unveiling the unknown diversity of planktonic green algae (Chlorophyta) in urban ponds in the semiarid region of Northeastern Brazil

Anticorpos anti-Brucella spp. em equídeos de tração em uma região semiárida do Nordeste do Brasil

ABSTRACT: The present study described the prevalence and factors associated with the seropositivity for anti-Brucella spp. antibodies in working equids in the semiarid regionofnortheastern Brazil. Blood samples were collected from 322 equids (76 horses, 155 mules and 91 donkeys). The Rose Bengal plate test (RBPT) was used as a screening method. Samples that were reactive in the RBPT were tested for confirmation using 2-mercaptoethanol (2-ME) and the standard tube agglutination test (STAT). Overall, 7.1% (23/322) of the samples were positive according to the RBPT. After confirmatory tests, the prevalence of brucellosis was found to be 6.5% (21/322). Among these cases, 33.3% (7/21) were horses, 42.8% (9/21) were mules and 23.9% (5/21) were donkeys. In the multivariate analysis, age over 10 years was considered to be a factor associated with the seropositivity (OR: 17.17; 95% CI: 2.582-164.7, P = 0.006) for anti-Brucella spp. antibodies. The significant prevalence of anti-Brucella spp. antibodies found in working equids and the wide distribution of positive animals demonstrates a worrying epidemiological situation regarding brucellosis in the study region. Age over 10 years was a risk factor associated with the seropositivity for anti-Brucella spp. antibodies in animals.

Factors shaping a lizard community structure in a semiarid region of north-eastern Brazil

We assessed the roles of historical and recent factors on the structure of a Neotropical lizard community from Serra da Capivara, in the semiarid Caatinga of north-eastern Brazil. We found no phylogenetic structure in community composition. Spatial niche overlap was high for most species pairwise comparisons. Null model analyses indicated that mean spatial and trophic niche overlaps did not differ, while mean morphological niche overlap was significantly lower than expected by chance, indicating a community structured along the morphological niche axis but not along the trophic nor spatial niche axes. We suggest that the lack of spatial niche segregation and species association may be related to current environmental conditions, such as habitat homogeneity and climatic variables. Morphological and dietary niches were influenced by historical factors, with phylogeny accounting for most of the variation in our data. Most of the variation is accounted for by the divergence of basal lineages (Gekkota/Scincomorpha/Iguania). These segregations influence behaviour and foraging modes of the given clades. Finally, these results are quite like those found for lizard communities in Seasonal Tropical Dry Forests (STDFs) and Cerrado savannahs, which can be a starting point to discuss the relationship between these formations to Caatinga domain.