Stream‐dwelling amphibians' occurrence, behaviour and reproductive success are strongly influenced by dynamic abiotic factors, for example, water flow and spray. These factors can disproportionately ...affect these frogs due to their dependency on specific favourable conditions for development and incapacity to disperse from unfavourable environments. We analysed the influence of environmental covariates on the detectability of Crossodactylus gaudichaudii, an amphibian species endemic to streams in the Brazilian Atlantic Forest. We conducted sampling in the streams of the Duas Bocas Biological Reserve, Brazil, and we measured air and water temperature, air humidity and pH of water on each sampling occasion. We estimated the effects of variables on the detectability of the species using single‐season occupancy models. Our results indicated that the detectability of the species increases on occasions with higher water temperatures (24–26°C) and lower pH (5.0–5.5). We investigated the influence of these covariates only on the detectability of adult frogs, but it is likely that the physiochemical properties of stream water are more important to aquatic larvae, and hence, the probability of their detection. Given this, further studies should examine the relevance of covariates on the detectability of adult frogs as well as larvae.
Our study investigated the influence of environmental factors on the detectability of Crossodactylus gaudichaudii, an amphibian species endemic to Brazilian Atlantic Forest streams. We found that higher water temperatures (24–26°C) and lower pH levels (5.0–5.5) positively influenced the detectability of adult frogs. Future research should also consider the relevance of these factors for larvae and their implications for conservation efforts.
Liolaemus lutzae is a small liolaemid lizard critically endangered and restricted to coastal restinga (salty sand dune habitats covered by herbaceous and shrubby vegetation by seaside) habitats of ...the state of Rio de Janeiro in Brazil. This lizard has been predicted to be extinct by 2080. We studied some of the environmental factors that influence occupancy by the species and detectability by the observer, in addition to investigating which populations remain occupying the areas along its original geographical distribution. We sampled 25 different beach habitats of restinga areas in the state, by 100‐meter replicates of linear transects. The estimated probability of occupancy was 69% (0.69 ± 0.05), and the estimated detectability was 50% (0.50 ± 0.03). The detection model with the best fit contained only the air temperature variable. Occupancy was best described by four variables: number of disturbance sources on the transect, vegetation cover in a 50‐meter buffer, exposed sand cover substrate in a 20‐meter buffer, and built‐up area cover in a 50‐meter buffer. No observations of L. lutzae were made in eight of the 25 restinga areas sampled along the original distribution of the lizard. In seven of these areas, the species had its populations extirpated many years ago, based on the 2007/2008 monitoring data. Conversely, in one area where the species was frequently observed during field surveys and different ecological studies on the species made in last decade, it was not recorded in the present study, indicating a possible recent population extirpation. We recommend that conservation measures be urgently implemented to mitigate anthropogenic impacts on the areas of the remaining populations of this lizard throughout its range, especially preserving the structure and functions of the remaining vegetation of beach habitat along restinga areas.
RESUMO
Liolaemus lutzae é um pequeno lagarto liolaemídeo criticamente ameaçado e restrito aos habitats de restinga (habitats de dunas costeiras cobertas por vegetação herbácea e arbustiva) do estado do Rio de Janeiro no Brasil. Este lagarto tem previsões de ser extinto até 2080, caso medidas não sejam tomadas. Estudamos alguns dos fatores ambientais que influenciam a ocupação pela espécie e a detectabilidade pelo observador, além de investigar quais populações deste lagarto permanecem ocupando as áreas ao longo de sua distribuição geográfica original. Foram amostrados 25 diferentes habitats de praia em áreas de restinga do estado, por meio de transectos lineares de 100 metros. A probabilidade estimada de ocupação foi de 69% (0,69 ± 0,05) e a detectabilidade estimada foi de 50% (0,50 ± 0,03). O modelo de detecção mais ajustado continha apenas a variável temperatura do ar. A ocupação foi melhor descrita por quatro variáveis: número de fontes de perturbação no transecto, cobertura vegetal em um buffer de 50 metros, cobertura de areia exposta em um buffer de 20 metros e cobertura de área construída em um buffer de 50 metros. Das 25 restingas amostradas, em oito delas não encontramos indivíduos de L. lutzae. Em sete dessas áreas a espécie teve suas populações extirpadas há muitos anos, com base nos dados de monitoramento de 2007/2008. Por outro lado, em uma área onde a espécie foi frequentemente observada durante diferentes estudos ecológicos realizados ao longo da última década, ela não foi registrada, indicando uma possível extirpação populacional recente. Recomendamos que, num curto espaço de tempo, sejam implementadas medidas de conservação para mitigar os impactos antrópicos nas áreas das populações remanescentes deste lagarto em toda a sua distribuição, preservando especialmente a estrutura e funções da vegetação remanescente do habitat de praia ao longo das áreas de restinga.
We studied factors that influence occupancy and detectability of a critically endangered lizard restricted to beach habitats of Rio de Janeiro, investigating the remaining populations along its distribution.
Arginase is an enzyme that converts L-arginine to urea and L-ornithine, an essential substrate for the polyamine pathway supporting Leishmania (Leishmania) amazonensis replication and its survival in ...the mammalian host. L-arginine is also the substrate of macrophage nitric oxide synthase 2 (NOS2) to produce nitric oxide (NO) that kills the parasite. This competition can define the fate of Leishmania infection.
The transcriptomic profiling identified a family of oxidoreductases in L. (L.) amazonensis wild-type (La-WT) and L. (L.) amazonensis arginase knockout (La-arg-) promastigotes and axenic amastigotes. We highlighted the identification of an oxidoreductase that could act as nitric oxide synthase-like (NOS-like), due to the following evidences: conserved domain composition, the participation of NO production during the time course of promastigotes growth and during the axenic amastigotes differentiation, regulation dependence on arginase activity, as well as reduction of NO amount through the NOS activity inhibition. NO quantification was measured by DAF-FM labeling analysis in a flow cytometry.
We described an arginase-dependent NOS-like activity in L. (L.) amazonensis and its role in the parasite growth. The increased detection of NO production in the mid-stationary and late-stationary growth phases of La-WT promastigotes could suggest that this production is an important factor to metacyclogenesis triggering. On the other hand, La-arg- showed an earlier increase in NO production compared to La-WT, suggesting that NO production can be arginase-dependent. Interestingly, La-WT and La-arg- axenic amastigotes produced higher levels of NO than those observed in promastigotes. As a conclusion, our work suggested that NOS-like is expressed in Leishmania in the stationary growth phase promastigotes and amastigotes, and could be correlated to metacyclogenesis and amastigotes growth in a dependent way to the internal pool of L-arginine and arginase activity.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Leishmania uses the amino acid L-arginine as a substrate for arginase, enzyme that produces urea and ornithine, last precursor of polyamine pathway. This pathway is used by the parasite to replicate ...and it is essential to establish the infection in the mammalian host. L-arginine is not synthesized by the parasite, so its uptake occurs through the amino acid permease 3 (AAP3). AAP3 is codified by two copies genes (5.1 and 4.7 copies), organized in tandem in the parasite genome. One copy presents the expression regulated by L-arginine availability.
RNA-seq data revealed 14 amino acid transporters differentially expressed in the comparison of La-WT vs. La-arg- promastigotes and axenic amastigotes. The 5.1 and 4.7 aap3 transcripts were down-regulated in La-WT promastigotes vs. axenic amastigotes, and in La-WT vs. La-arg- promastigotes. In contrast, transcripts of other transporters were up-regulated in the same comparisons. The amount of 5.1 and 4.7 aap3 mRNA of intracellular amastigotes was also determined in sample preparations from macrophages, obtained from BALB/c and C57BL/6 mice and the human THP-1 lineage infected with La-WT or La-arg-, revealing that the genetic host background is also important. We also determined the aap3 mRNA and AAP3 protein amounts of promastigotes and axenic amastigotes in different environmental growth conditions, varying pH, temperature and L-arginine availability. Interestingly, the increase of temperature increased the AAP3 level in plasma membrane and consequently the L-arginine uptake, independently of pH and L-arginine availability. In addition, we demonstrated that besides the plasma membrane localization, AAP3 was also localized in the glycosome of L. amazonensis promastigotes and axenic amastigotes.
In this report, we described the differential transcriptional profiling of amino acids transporters from La-WT and La-arg- promastigotes and axenic amastigotes. We also showed the increased AAP3 levels under amino acid starvation or its decrease in L-arginine supplementation. The differential AAP3 expression was determined in the differentiation of promastigotes to amastigotes conditions, as well as the detection of AAP3 in the plasma membrane reflecting in the L-arginine uptake. Our data suggest that depending on the amino acid pool and arginase activity, Leishmania senses and could use an alternative route for the amino acid transport in response to stress signaling.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
SARS-CoV-2 has spread worldwide and has become a global health problem. As a result, the demand for inputs for diagnostic tests rose dramatically, as did the cost. Countries with inadequate ...infrastructure experience difficulties in expanding their qPCR testing capacity. Therefore, the development of sensitive and specific alternative methods is essential. This study aimed to develop, standardize, optimize, and validate conventional RT-PCR targeting the N gene of SARS-CoV-2 in naso-oropharyngeal swab samples compared to qPCR. Using bioinformatics tools, specific primers were determined, with a product expected to be 519 bp. The reaction conditions were optimized using a commercial positive control, and the detection limit was determined to be 100 fragments. To validate conventional RT-PCR, we determined a representative sampling of 346 samples from patients with suspected infection whose diagnosis was made in parallel with qPCR. A sensitivity of 92.1% and specificity of 100% were verified, with an accuracy of 95.66% and correlation coefficient of 0.913. Under current Brazilian conditions, this method generates approximately 60% savings compared to qPCR costs. Conventional RT-PCR, validated herein, showed sufficient results for the detection of SARS-CoV-2 and can be used as an alternative for epidemiological studies and interspecies correlations.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Canine kobuvirus (CaKV) is a member of the
Picornaviridae
family and the
Kobuvirus
genus. CaKV was first described in fecal samples from diarrheic dogs in the USA in 2011, with subsequent reports in ...the UK, Italy, South Korea, China, Tanzania, and Japan. CaKV is frequently identified in feces of animals with or without clinical signs of gastroenteritis. The present study investigated the presence of CaKV in fecal samples from 53 diarrheic dogs from Londrina, southern Brazil. Using a RT-PCR assay, CaKV RNA was identified in three dogs, resulting in an overall occurrence rate of 5.7%. In addition, coinfection with canine parvovirus subtype 2b was detected in all CaKV-positive diarrheic fecal samples. Using a phylogenetic analysis based on the VP1 gene sequence, the Brazilian CaKV field strains were found to be very similar to a previously identified CaKV strain from Brazil that was found in the tissue of a puppy and were also found to be clustered with other CaKV strains detected worldwide and other kobuvirus strains identified in mouse, feline, and human hosts.
Asymptomatic and underreported individuals remain a source of coronafig disease 2019 (COVID-19) transmission to others. Data on the prevalence and epidemiological factors influencing transmission are ...fundamental for establishing control measures, especially in vulnerable regions such as the Amazon. This study aimed to determine the point prevalence and active infection of COVID-19 among the population in Araguaína, a Brazilian city located in the Amazon region, analyzed the socioeconomic and behavioral variables of a statistically representative sample of this population using an epidemiological survey, and identify the viral genomic diversity in the region. During the sixth epidemiological week of 2021 (February 8 to 12), samples of 497 inhabitants of the municipality asymptomatic for respiratory syndromes underwent reverse transcription-quantitative polymerase chain reaction and serological tests (immunoglobulin M and immunoglobulin G). A questionnaire collated data on socioeconomic factors, prevention measures, and health status history. The active infection rate was 6.2%, and the prevalence was 13.5% of the study population. Active infection cases were under-reported; each reported positive case represented 14-28 under-reported cases. Lineages P.2, P.1, and B.1.1 were detected. Working from home was a protective factor against the infection, and clinical signs of fever, dry cough, and loss of taste or smell were associated with testing positive (p <0.05). A descriptive analysis of the indicators revealed that the entire population was susceptible to the disease. Intensified vaccination strategies are required regardless of socioeconomic factors, health conditions, and preventive measures. Implementation of objective, comprehensive, and efficient management tools to minimize the spread of COVID-19 in this municipality can serve as a model for other regions of Brazil.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
There has recently been great concern with the performance of science and technology parks (STPs). This paper proposes a reference model for the strategic performance management of STPs built on the ...theoretical bases of service dominant logic and the balanced scorecard. We conducted a survey of the strategic managers and owners of 84 firms located in 15 different STPs in Brazil. The research model was validated using Structural Equation Modeling. The results validated a set of performance indicators in a management model that can be used to better manage these endeavors.
The effect of laser remelting on the corrosion susceptibility and mechanical properties of Ti-35Nb-4Sn (mass%) alloy is investigated across the remelted track profile. In comparison to the ...cold-rolled microstructure of base metal, recrystallization of heat affected zone (HAZ) improved plastic energy absorption and pitting corrosion resistance, by the reduction of active sites for pit nucleation. In fusion zone, however, passivation was compromised by the formation of dendritic microstructure with Sn enriched interdendritic region, where preferential pitting corrosion occurred. Fusion zone was the most anodic region and presented a corrosion potential difference of 35 mV, in comparison to the adjacent and most cathodic HAZ. Electrochemical impedance analysis showed that spontaneous passivation was most effective in base metal, that developed a thicker and more compact passive film. Local increase in elastic modulus and microhardness of fusion zone shows that laser remelting is a viable processing route for the manufacturing of biomaterials with functionally graded properties.
Elevational gradients usually help to explain the potential factors underlying global biodiversity, as changing altitude leads to strong habitat changes in a relatively small area. We tested the ...influence of the altitude gradient on the small non‐volant mammal’s community along the regional landscape of the Atlantic Forest located of the Espírito Santo state, Brazil. We trapped non‐volant small mammals from January 2017 to October 2018 in 12 locations distributed along an altitude gradient ranging from sea level to 2100 m above sea level (asl). We ordered the non‐volant small mammal species by using a Non‐Metric Multidimensional Scaling analysis using the Bray–Curtis metric. To understand how the altitude, vegetation types and climate variables influence the richness and abundance of species, we fitted generalised linear model. We observed that small mammal species composition differed according to altitude, with higher richness in locations with intermediate altitude between 500–1500 m asl. In locations with higher altitude, between 1501–2200 m asl, we recorded a lower species richness, but higher endemism. Our results suggest altitude influenced the community of non‐volant small mammals. However, altitude direct influence on other variables is not evaluated in the present study, such as food availability. In addition, we found a high endemism in higher altitude areas, pointing out the importance of conserving these mountain areas for the preservation of endemic species. Thus, highlighting the importance of this study to suggest areas that deserve greater attention in the development of management and conservation plans.
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