Semi-arid Northeast Brazil Research Articles

Resistance of Corynebacterium pseudotuberculosis in the Brazilian semiarid environment

ABSTRACT: The semiarid northeast of Brazil contains a unique biome known as caatinga, with a maximum temperature of 40 ºC and a relativity humidity of 56%. The caatinga is characterized by a variety of plants, including Cereus jamacaru Dc (mandacaru), Poincianella microphylla Mart. ex G. Don (catingueira), Pilosocereus gounellei FAC Weber (xique-xique) and Mimosa tenuiflora (Willd.) Poir (jurema preta). Sheep and goat industries are economically strong in that region, despite the fact that caseous lymphadenitis is highly prevalent. The aim of the present study was to assess the survival and biofilm production of Corynebacterium pseudotuberculosis isolates in the environment and under controlled temperatures (28°C, 37°C and 42°C) under different surfaces (plants, soil, wood, wire and thorns). In addition, we investigated the effects of applying the disinfectants chlorhexidine, hypochlorite and quaternary ammonia in soil, tiles, wood and vegetation cover. Four strains of C. pseudotuberculosis were selected (two from goats and two from sheep) for inoculation according to their in vitro biofilm production. Adherence to microplates was used to assess the biofilm-forming ability of the bacteria. Lower survival rates were observed when isolates of C. pseudotuberculosis were subjected to a temperature of 42°C. In terms of caatinga biome plants, contamination of jurema-preta plants resulted in the lowest survival rates. The disinfectant quaternary ammonia promoted a lower inoculum survival in all surfaces. The disinfectants and the higher temperature contributed to the reduction of biofilm production in isolates of C. pseudotuberculosis. knowledge of these patterns is important for the establishment of disease control measures, given the questionable efficacy of the treatment and the immuno-prophylaxis of caseous lymphadenitis.

Soil CO2 Efflux Measurements by Alkali Absorption and Infrared Gas Analyzer in the Brazilian Semiarid Region

ABSTRACT The CO2 emission from the soil surface, commonly referred to as soil CO2 efflux (ECO2) or soil respiration, is the sum of processes that include root respiration and microbial activity. Measuring this evolution is important to establish sustainable land use models and to estimate global fluxes of carbon, which affect climate change. Despite its importance, few measurements have been made in areas of the semiarid Brazilian Northeast region, and most of them were made using the alkali absorption method [...]

Frequency, duration and severity of drought in the Semiarid Northeast Brazil region

ABSTRACTDrought is the natural disaster that impacts the greatest number of people and produces the most significant economic losses. This work presents a quantitative assessment of drought events occurred in the Semiarid region of Northeast Brazil during 1981–2016. The purpose of this study is to provide an overview of drought intensity for the last 36 years, analysing their severity, frequency and duration, considering hydro‐meteorological and agricultural aspects. To evaluate these two aspects, the 12‐month standardized precipitation index and the vegetation health index were considered to investigate drought characteristics. The definition of drought event for both these indices was performed regarding start and end month. In this context, drought duration is considered equal to the number of months of event, drought frequency is the number of events per time period and the drought severity is the absolute value of integral area below zero. Results show that the most severe and prolonged drought occurred in 2011–2016. In a clear contrast to previous droughts in past decades, during these last 5‐years period drought were more frequent, severe and affected a larger area with significant impacts for population, as well as economical activities.

Optimal Foraging Theory Perspectives on the Strategies of Itinerant Beekeepers in Semiarid Northeast Brazil

Foraging theory has been widely used to understand patterns associated with obtaining resources and the optimal cost-benefit relationship between forager and resource. However, many analytical theoretical models do not consider the influence of social groups on forager strategy. We analyzed strategies for obtaining resources from two perspectives: individual and social. For the first, we tested hypotheses that addressed whether individual strategies followed the predictions of classic models of foraging theory. In the second approach, we investigated potential social influences on resource-obtaining strategies. Our results suggest that regardless of the strategy adopted by the forager (specialist or generalist), environmental factors, such as abundance, regulated success in obtaining resources. However, we observed that specialists had a greater advantage relative to generalists when resources were abundant. We also observed that forager decision-making was related to the social context of the individual forager, which influenced their strategies.

Validating CHIRPS-based satellite precipitation estimates in Northeast Brazil

Satellite-based rainfall is an alternative source of information for regions such as the Northeast Brazil (NEB) where there are large areas that do not have ground observation stations. In this study, the monthly rainfall derived from the satellite-based rainfall product, Climate Hazards Group InfraRed Precipitation with Stations (CHIRPS v.2), is compared with observation from 21 ground stations in the NEB, for the period 1981–2013. Various metrics based on pairwise comparison were applied to evaluate its performance in estimating rainfall amount and rain detection capability. Results show that the CHIRPS data correlate well with observations for all stations (r = 0.94), but tend to overestimate low and underestimate high rainfall values (>100 mm/month). Although CHIRPS achieves better results during the wet season (March to May; bias = −4.60%), its ability for the rain detection is poor (probability = 0.44). The best global performance was noted in the Cerrado biome (r = 0.93; rain detection = 0.53), but fails to detect rain in other biomes (r = 0.92; rain detection = 0.16). The study concluded that the CHIRPS v.2 dataset can be a useful substitute for rain-gauge precipitation data outside the semiarid NEB.

Growth and volatile compounds of Martianthus leucocephalus exposed to heavy metal stress

ABSTRACT: Martianthus leucocephalus is found in the semi-arid Northeast of Brazil and has high pharmacological potential due to the production of volatile compounds. This study aimed to evaluate the Cd (15, 30, 45 and 60µmol L-1), Cu (30, 60, 90 and 120µmol L-1) and Zn (150, 300, 450 and 600µmol L-1) levels on the growth of this species and its volatile compounds production. Apical cuttings were placed in plastic trays containing 6.0L nutrient solution, and after rooting, they were submitted to Cd, Cu and Zn treatments for 15 days. All the metals evaluated reduced the succulence and growth of all parts of M. leucocephalus . This effect was accompanied by the increase of Cd, Cu and Zn concentrations in all plant tissues. Volatile compounds content produced by M. leucocephalus was increased only by Zn (86%).

SEROLOGICAL EVIDENCE OF EXPOSURE TO Ehrlichia canis IN CATS

Abstract The aim of the present study was to estimate the occurrence of Ehrlichia canis in cats from the semiarid region of Northeast of Brazil. Sera of 101 healthy cats were submitted by Indirect Immunofluorescence Assay (IFA), and considered positive when antibody titers ≥ 40 were obtained. Seroprevalence of 35.6% (36/101) was found, with the following titers: 40 (15 animals); 160 (6); 320 (1); 640 (3), and 2,560 (11). No statistical differences were observed when comparing county of origin, gender, age, breed, and modus vivendi (pet and stray cats), and no ticks were observed in any of the cats. This study revealed exposure to E. canis in cats of the Semiarid Northeast of Brazil.

Nutrient load concept-reservoir vs. bay impacts: a case study from a semi-arid watershed.

Large flow-through reservoirs and lakes possess environmental gradients and monitoring programs are mostly adapted for cost and time effectiveness. Bay areas are often more isolated from the main water body and are likely to have unobserved different environmental processes and impacts. This study was performed at the Itaparica Reservoir, São Francisco River, located in semi-arid Northeast Brazil, with dendritic form. Water residence time in the Icó-Mandantes Bay was estimated by hydrodynamic flow and transport simulations. The P-chlorophyll a relationship was used to develop the P use efficiency coefficient for critical P load estimation of 25 μg P L-1. Phosphorus sources and input rates into a bay and the respective reservoir were calculated and compared regarding their different origins for the period after flooding (1988) and for 2013. After impoundment, the P load highly exceeded the carrying capacity because of leaching and mineralization processes. In 2013, P inputs were still above this threshold, whereas inflow and sub-basin P export during the rainy season were crucial. But eutrophication processes have increased in the bay relative to the main water body. Hence, water in hydraulic isolated parts is prone to eutrophication processes, thus, bays have to be specially considered in water resource management.

Dracontium nivosum (Lem.) G.H.Zhu (Araceae): range extension from Amazonia to a brejo forest refugium in Northeast Brazil confirmed

The 558 km range extension of the Amazonian aroid Dracontium nivosum (Lem.) G.H.Zhu into semi-arid Northeast Brazil is confirmed. This species occurs in Ceará in threatened fragments of brejo forest at ca. 580–870 m elevation. An illustrated taxonomic description is provided. The species’ Extent of Occurrence (EOO) is estimated as 356,392 km2 (meets Least Concern); the Area of Occupancy (AOO), 60 km2 using a 2×2 km cell (Endangered). Within Ceará the EOO is 41.4 km2 (Critically Endangered) and the AOO is 16 km2 (Endangered).

ANTI-Lentivirus, Brucella abortus AND B. ovis ANTIBODIES IN SMALL RUMINANTS RAISED IN PERNAMBUCO AND BAHIA

ABSTRACT: Goat and sheep production in the semi-arid northeast of Brazil has shown great economic potential. However, health problems can compromise the productivity of these animals. Given the scarcity of studies about the occurrence of these diseases, the aim of the present study was to analyze the serological diagnosis of anti-Brucella and anti-lentivirus antibodies among small ruminants in municipalities located in the Brazilian states of Bahia and Pernambuco. The samples were collected from local slaughterhouses and dairy farms. In total, 997 serum samples from animals in slaughterhouses and dairy herds were collected. In order to diagnose the caprine arthritis encephalitis virus (CAEV), the samples underwent agarose gel immunodiffusion (AGID) testing. The buffered acidified antigen test (goats) and agarose gel immunodiffusion test (sheep) were used to detect anti-Brucella abortus and B. ovis antibodies following the methodology recommended by the Institute of Technology of Paraná (TECPAR). With anti-CAEV antibodies, seropositivity rates of 4.1% and 2.2% were recorded for animals from the slaughterhouses and dairy farms, respectively. None of the animals (goats or sheep) were positive for anti-B. abortus antibodies. With B. ovis, a seropositivity rate of 6.5% (n = 13) was recorded among the 199 sheep serum samples. Results of the present study confirmed the presence of the CAE virus in the meat and dairy herds studied, although the prevalence was low. Natural infection by B. abortus did not occur in the goat and sheep herds assessed. Seropositivity for B. ovis was confirmed, although prevalence was low. Direct tests are required to diagnose ovine brucellosis.

An Index of Susceptibility to Drought (ISD) for the Semiarid Brazilian Northeast

Abstract This work presents the development of a composite Index of Susceptibility to Drought (ISD) for semiarid Brazilian Northeast that considers climatology, physical properties, soil usage, social and economic aspects, the risk of harvest losses and the shortage of human and animal drinking water. The index started with the Index FUNCEME of drought Severity (IFS), developed by FUNCEME. Then, it evolved to use some tools proposed by the Joint Research Centre/Organization for Economic Co-operation and Development (JRC/OECD), as well as techniques of multiple imputation for missing data and data winsorization. The work was tested and validated with real data from Rio Grande do Norte State in three climatologic scenarios (dry, regular and rainy). A multivariate analysis test and a Monte Carlo simulation were also produced for a sensibility and strength analysis of the developed model. These analyses validated the composition model and the obtained results with real data. The ISD can be used as a tool to support decision makers in various government levels to help guide the actions for the drought-affected areas.

Effect of pFSH dose reduction on in vivo embryo production in Dorper ewes

<p>To evaluate the effect of pFSH dose on the <em>in vivo </em>embryo production of Dorper ewes in the semi-arid northeast of Brazil, 40 sheep females were distributed into two groups of 20 animals that received intravaginal CIDR for 14 days, and two days before device removal, they received one of the following treatments: in the FSH200 group, the ewes received 200 mg of pFSH; and in the FSH128 group, the ewes received a total of 128 mg in decreasing doses every 12 h. Beginning 12 h after the conclusion of the treatments, estrus detection was performed every four hours using two Dorper rams of proven fertility. The ewes were mated at estrus onset and 24 hours later. Seven days after intravaginal device removal, the superovulatory response was evaluated, and embryo collection was performed using the laparotomy method. The recovered flushings were subjected to embryo searches under a stereomicroscope and classified according to their qualities. Analyses of variance (ANOVAs) and LSD tests were used to compare the different parameters. The data expressed as percentages were analysed by chi-square test. The ovulation rate was higher in the FSH200 group, which had 16.3 ± 0.3 corpora lutea (CL), than in the FSH128 group, which had 11.3 ± 0.3 CL (P<0.05). However, higher fertilization rate (83.6% vs. 62.4%) and higher transferable (86.0% vs. 71.6%) and freezable (67.9% vs. 40.8%) embryo rates were observed in the FSH 128 group compared with the group that received 200 mg. Furthermore, no significant differences in the remaining parameters were observed between the experimental groups (P>0.05), demonstrating that pFSH dose reduction promoted a greater production of freezable and transferable embryos in Dorper ewes subjected to MOET.</p>

Effect of pFSH dose reduction on in vivo embryo production in Dorper ewes

To evaluate the effect of pFSH dose on the in vivo embryo production of Dorper ewes in the semi-arid northeast of Brazil, 40 sheep females were distributed into two groups of 20 animals that received intravaginal CIDR for 14 days, and two days before device removal, they received one of the following treatments: in the FSH200 group, the ewes received 200 mg of pFSH; and in the FSH128 group, the ewes received a total of 128 mg in decreasing doses every 12 h. Beginning 12 h after the conclusion of the treatments, estrus detection was performed every four hours using two Dorper rams of proven fertility. The ewes were mated at estrus onset and 24 hours later. Seven days after intravaginal device removal, the superovulatory response was evaluated, and embryo collection was performed using the laparotomy method. The recovered flushings were subjected to embryo searches under a stereomicroscope and classified according to their qualities. Analyses of variance (ANOVAs) and LSD tests were used to compare the different parameters. The data expressed as percentages were analysed by chi-square test. The ovulation rate was higher in the FSH200 group, which had 16.3 ± 0.3 corpora lutea (CL), than in the FSH128 group, which had 11.3 ± 0.3 CL (P<0.05). However, higher fertilization rate (83.6% vs. 62.4%) and higher transferable (86.0% vs. 71.6%) and freezable (67.9% vs. 40.8%) embryo rates were observed in the FSH 128 group compared with the group that received 200 mg. Furthermore, no significant differences in the remaining parameters were observed between the experimental groups (P>0.05), demonstrating that pFSH dose reduction promoted a greater production of freezable and transferable embryos in Dorper ewes subjected to MOET.

An approach to assess the impact of landscape connectivity and effective catchment area upon bedload sediment flux in Saco Creek Watershed, Semiarid Brazil

Sediment flux in semi-arid drainage networks is influenced by landscape connectivity, wherein natural landforms and hydro infrastructure networks such as low order dams impede the downstream transfer of sediment. This study analyzes how drainage impediments affect bedload transport within Saco Creek watershed, in semi-arid northeast Brazil. Geomorphology and land use maps are constructed to assess changes to short term landscape connectivity. Bedload conveyance is appraised for precipitation/runoff events of variable magnitude-frequency relationships. From this, ‘effective’ rainfall events are determined. Analysis of the type and location/pattern of drainage impediments is used to assess effective catchment area under three distinct runoff scenarios. In the low magnitude event scenario, only 33.8% of the watershed area contributed effectively to sediment flux. In moderate and high magnitude events this value increased to 61.6% and 70.8% respectively. The relatively small variation from moderate to high magnitude events reflects the operation of dams which store bedload sediments. Findings from this study can be used to show how landscape connectivity analysis can support dam management in semiarid agrarian landscapes.

Umbuzeiro (Spondias Tuberosa): a systematic review

Spondias tuberosa Arruda, a fructiferous endemic tree of semiarid Northeastof Brazil, provides several services to its ecosystem as well as to humans. Itprovides feed for wild animals and domestic ruminants in addition to providingfruits that are rich in vitamins for the human diet. It is an important source ofadditional income for family farmers and a source for traditional therapeuticmedicine. Despite the importance of this tree in northeastern Brazil, limitedscientific effort have been accomplished so far towards a better understandingof the tree’s physiology and interaction within the ecosystem. Earlier studiesabout S. tuberosa focused on phenology, physiology, population genetics,management practices, and socioeconomic aspects. Due to the lack ofbreeding and cloning programs, physiological studies and management trialswere based on heterogenic plant material, which led to ambiguous results.In order to move forward with S. tuberosa research, especially for its geneticconservations and agro-industrial exploitation, basic breeding and intensifiedgenetic research are urgently required. Despite the few publications on S.tuberosa, the tree can be considered scientifically neglected, particularly ifcompared with other members of the Anacardiaceae family.

Daily activity patterns of Saanen goats in the semi-arid northeast of Brazil

The objective of the study was to characterize the daily feeding activity patterns of Saanen goats (Capra hircus) as a function of changes in climatic variables. The investigation was conducted in the municipality of Cruzeta, 300 km from the city of Natal, Brazil. Seventeen free-ranging female Saanen goats were selected for observation, wherein they were kept on a pasture with native vegetation and also received concentrated feed in a trough. Observational records of behavior on pasture were collected using focal animal and scan sampling for these specific behaviors: ruminating while standing or lying down, standing idly or lying down, walking, grazing and eating. Eating was the predominant activity observed. The frequency of some behaviors changed in accordance with certain climatic variables, with behaviors that require more active movement occurring in the morning hours, when temperatures are milder, exhibiting higher frequencies. These observations indicate that animals adjust their daily activities in order to minimize the effects of the stress caused primarily by environmental conditions.

Estudo retrospectivo das neoplasias em ruminantes e equídeos no semiárido do Nordeste Brasileiro

No Brasil, dados relacionados com a ocorrência de neoplasias em ruminantes e equinos são escassos. Objetivou-se com este trabalho determinar a frequência de neoplasias diagnosticadas em bovinos, caprinos, ovinos e equídeos no Laboratório de Patologia Animal da Universidade Federal de Campina Grande, Patos, Paraíba, durante o período de 1983 a 2010 e analisar os fatores de risco, mediante o teste de qui-quadrado, considerando como variáveis, espécie, raça, sexo e idade. Durante o período foram registrados 177 (5,6%) tumores de um total de 3.153 diagnósticos provenientes de biópsias e necropsias. Houve diferenças significantes (p<0,001) na frequência de tumores entre as diferentes espécies sendo mais acometidos os equinos (10,6%), seguidos pelos bovinos (6,8%), caprinos (3,3%) e ovinos (2,1%). Os tumores mais frequentes foram o carcinoma células escamosas (CCE) nos bovinos (58,3%), ovinos (80%) e caprinos (46,1%) e o sarcoide em equinos (45,3%). Quanto à localização anatômica, as neoplasias foram mais frequentes na pele em equídeos (62,5%) e ovinos (60%), olho e tecido periocular em bovinos (36,1%) e sistema reprodutor feminino (períneo e vulva) em caprinos (34,6%). Em relação ao sexo dos animais, apenas os bovinos apresentaram prevalência significativa (p<0,001). Em relação à idade apenas os caprinos apresentaram prevalência significativa (p=0,015). Não houve prevalência significativa em nenhuma espécie em relação à raça. Conclui-se que os carcinomas de células escamosas em ruminantes e o sarcoide em equídeos são os tumores mais frequentes em animais de produção no semiárido do Nordeste Brasileiro e que a espécie equina foi a mais acometida dentre as espécies estudadas.

Spatial-temporal variation of parasites in Cnemidophorus ocellifer (Teiidae) and Tropidurus hispidus and Tropidurus semitaeniatus (Tropiduridae) from Caatinga areas in northeastern Brazil

Parasites are natural regulators of their host populations. Despite this, little is known about variations in parasite composition (spatially or temporally) in environments subjected to water-related periodic stress such as the arid and semiarid regions. The objective of this study was to evaluate the spatial-temporal variation in endoparasite species' abundance and richness in populations of Neotropical Cnemidophorus ocellifer, Tropidurus hispidus, and Tropidurus semitaeniatus lizards in the semiarid northeast of Brazil. The location influenced the abundance of parasites in all analyzed lizard species, while season (dry and rainy) only influenced the total abundance for T. hispidus. In all seasons, males significantly showed more endoparasites than females in all lizard species, although for T. hispidus, this difference was only found in the dry season. Seasonal variations affect the abundance patterns of parasites. Likely, variables include environmental variations such as humidity and temperature, which influence the development of endoparasite eggs when outside of the host. Further, the activity of the intermediate hosts and the parasites of heteroxenous life cycles could be affected by an environmental condition. The variation in the abundance of parasites between the sampling areas could be a reflection of variations in climate and physiochemical conditions. Also, it could be due to differences in the quality of the environment in which each host population lives.

Root and shoot biomasses in the tropical dry forest of semi-arid Northeast Brazil

Root and shoot biomasses and their ratio (R:S) were determined for three stages of forest regeneration (18, 40 and > 60 years.), and for open and dense vegetation, in four soil classes in the semi-arid region of Northeast Brazil. Shoot biomasses were estimated by allometry and roots were collected in 0.7 × 0.7 × 1 m trenches. Root and shoot biomasses and the R:S ratio were over double in the >60 year-old vegetation (R:S = 0.67) when compared to more recent regenerated areas (0.32). In dense vegetation the biomass of roots and shoots were also more than the double of those in open vegetation but the R:S ratios were not significantly different (0.51 and 0.49). Litholic Neosols had lower ratio (0.22) than the other soil classes (0.53 to 0.63) and dense and open vegetation did not differ. In all areas except in deep sandy Quartzarenic Neosols most of the roots (> 90 %) were in the upper 40-cm layer of the soil profile, and consisted of coarse roots. Root biomass accumulates more slowly than aboveground biomass and it takes several decades to stabilize in shallower soils. The R:S ratios are higher when compared to other dry land forests, probably due to low water availability.

Water quality and microbial diversity in cisterns from semiarid areas in Brazil.

Harvesting rainwater is a common practice worldwide, particularly in areas with no access to a public water supply or insufficient groundwater reserves. More than two million people living in semiarid regions of Brazil consume rainwater stored in cisterns, and little information is available regarding the water quality. Despite the initial good quality of the rainwater, its harvest and storage can introduce contaminants that must be eliminated before consumption. To evaluate the influence of handling, cistern age and precipitation on the quality of harvested rainwater, we monitored seven cisterns in the semiarid Brazilian Northeast over 4 years. Microbial and physicochemical parameters were monitored once a month, and denaturant gradient gel electrophoresis (DGGE) was performed at the end of the monitoring period. Coliform bacteria were detected in 100% of samples, while Escherichia coli were observed in 73.8%. The alkalinity and conductivity were the highest for the recently built cisterns due to the dissolution of construction materials. The DGGE of the 16S r DNA did not reveal the presence of E. coli. Instead, DGGE bands sequencing indicated that species primarily affiliated with Alphaproteobacteria were present in all cisterns, indicating the presence of microbial ecosystems capable of purifying and stabilizing the stored rainwater.