Numerical Investigation of Dimensionless Parameters in Carangiform Fish Swimming Hydrodynamics.

Research into how fish and other aquatic organisms propel themselves offers valuable natural references for enhancing technology related to underwater devices like vehicles, propellers, and biomimetic robotics. Additionally, such research provides insights into fish evolution and ecological dynamics. This work carried out a numerical investigation of the most relevant dimensionless parameters in a fish swimming environment (Reynolds Re, Strouhal St, and Slip numbers) to provide valuable knowledge in terms of biomechanics behavior. Thus, a three-dimensional numerical study of the fish-like lambari, a BCF swimmer with carangiform kinematics, was conducted using the URANS approach with the k-ω-SST transition turbulence closure model in the OpenFOAM software. In this study, we initially reported the equilibrium Strouhal number, which is represented by St∗, and its dependence on the Reynolds number, denoted as Re. This was performed following a power-law relationship of St∝Re(-α). We also conducted a comprehensive analysis of the hydrodynamic forces and the effect of body undulation in fish on the production of swimming drag and thrust. Additionally, we computed propulsive and quasi-propulsive efficiencies, as well as examined the influence of the Reynolds number and Slip number on fish performance. Finally, we performed a vortex dynamics analysis, in which different wake configurations were revealed under variations of the dimensionless parameters St, Re, and Slip. Furthermore, we explored the relationship between the generation of a leading-edge vortex via the caudal fin and the peak thrust production within the motion cycle.

Metabolic responses in the gills of Yellowtail Lambari Astyanax lacustris under low- and high-temperature thermal stress.

OBJECTIVE: Ectothermic fish are directly affected by temperature changes in the environment. The aim of this study was to evaluate the metabolic responses in the gills of Yellowtail Lambari Astyanax lacustris under thermal stress. METHODS: To this end, we used spectrophotometry to evaluate the biomarkers of carbohydrate and protein metabolism, antioxidant defense, and oxidative damage in fish subjected to low (15°C) and high (31°C) temperatures, with control groups held at 23°C, for 2, 6, 12, 24, 48, and 96 h. RESULT: The results showed that cold thermal stress did not change the energy demand, and the antioxidant defense was reduced; therefore, the gills were vulnerable to the action of reactive oxygen species (ROS), presenting increased protein carbonylation at 12 h. With heat thermal stress, a higher energy demand was observed, which was verified by an increase in aerobic metabolism by glycolysis and the citric acid cycle. High-temperature stress also increased the antioxidant defenses, as verified by the increased activities of glutathione peroxidase, glutathione reductase, and glutathione S-transferase. However, the antioxidant defense system could not protect tissues from the action of ROS, as protein carbonylation increased at 6 and 24 h, indicating oxidative stress. CONCLUSION: The results showed that (1) temperature variations caused metabolic adjustments in the gills of Yellowtail Lambari, (2) the adaptive responses were different for winter and summer temperatures, and (3) Yellowtail Lambari recovered homeostasis when subjected to thermal stress, even with the occurrence of oxidative stress.

Induced reproduction of yellow-tailed lambari (Astyanax lacustris) with Ovopel® and buserelin acetate as alternatives to the protocol with carp pituitary extract.

The objective of this study was to evaluate reproductive traits in adults of Astyanax lacustris subjected to different spawning inducers. The study involved 240 females (12.54 g ± 2.33 and 7.66 cm ± 0.63 cm) and 240 males (5.83 g ± 0.39 g and 6.14 cm ± 0.64 cm), all at reproductive age. Three different inducers were evaluated: (i) 0.4 pellets of Ovopel®/kg of body weight; (ii) 0.5 ml of buserelin acetate/kg of body weight; and (iii) carp pituitary extract (CPE) (5.5 mg CPE/kg body weight for females and 2.5 mg CPE/kg body weight for males), as well as saline solution (without hormone). The degree-hours for spawning were greater (P<0.05) for the Ovopel® treatment (with 204.93) than in the treatment with CPE (183.2). Ovary weight and gonadosomatic index were higher (P<0.05) in CPE and Ovopel® treatments when compared to buserelin acetate. The number of oocytes per female, absolute and relative fecundity were greater (P<0.05) for Ovopel® and CPE treatments. Fertilization rate was higher (P<0.05) in treatment with buserelin acetate (82.3%) in relation to Ovopel® (72.33%) and CPE (62.40%) treatments, and the highest (P<0.05) hatching rates were achieved with buserelin acetate and Ovopel®. The number of larvae per female body weight was greater (P<0.05) when Ovopel® was used. In conclusion, Ovopel® proves to be a more effective reproductive inducer for induced reproduction of A. lacustris when compared to CPE and buserelin acetate.

Effects Caused by the Ingestion of Microplastics: First Evidence in the Lambari Rosa (Astyanax altiparanae).

Microplastics are a class of contaminants that pose a threat to aquatic biota, as they are easily found in aquatic ecosystems and can be ingested by a wide variety of organisms, such as fish. The lambari rosa (Astyanax altiparanae) is a microphage fish, which feeds on microscopic beings and particles, making it potentially susceptible to ingesting MPs discarded in the environment. In addition, this fish is of great economic and food importance, as it is used for human consumption. This study aimed to evaluate the accumulation and possible toxicological effects caused to lambari rosa (n = 450) by the ingestion of polyethylene (PE) and polyethylene terephthalate (PET) MPs, since the MPs of these polymers in the form of granules, fragments, and fibers are the most commonly reported in the aquatic environment. The parameters investigated here were the quantitative analysis of ingested MPs using microscopic and staining techniques, as well as the mortality rate, malformations/injuries, and impaired weight gain. At the end of the experiment, it was concluded that MPs from both polymers accumulated in the gastrointestinal tract of the lambari rosa, and that dietary exposure, especially to the PET polymer, was responsible for increasing the mortality rate in this species.

Bioaccumulation and Depletion of the Antibiotic Sulfadiazine 14C in Lambari (Astyanax bimaculatus).

Antibiotics are present in the environment, primarily due to their release through wastewater treatment plants, agricultural practices, and improper disposal of unused medications. In the environment, these drugs can be bioaccumulated by organisms and transferred along the food chain. This is a problem when considering the consumption of fish meat. In the United States, legislation stipulates that the maximum residue limit for sulfadiazine (SDZ) should not exceed 100 µg kg-1. Lambari fishes have potential economic importance in aquaculture, as they are relatively easy to breed and can be raised in small-scale operations. Finally, studying the biology and ecology of lambari could provide valuable information about freshwater ecosystems and their inhabitants. The current work aimed to measure the bioaccumulation and depletion of the antibiotic SDZ 14C in lambari (Astyanax bimaculatus). For this purpose, the tests were divided into two stages; seven days of exposure and seven days of depletion, where one fish was randomly selected and sampled every day. In the exposure phase, the fish were fed the medicated feed three times a day at a concentration of 2.5 mg·g-1. The control fish were fed uncontaminated feed. For the depletion phase, the remaining lambari were transferred to clean tanks and fed uncontaminated feed three times a day. The fish samples were burned in the Oxidizer and the reading of radioactivity was performed in a liquid scintillation spectrometer. It is worth noting that on day 7 and day 14, the water in the aquariums was filtered through filter paper to collect the metabolic excrement. SDZ concentrations increased over the days and accumulation occurred in the fish, with day seven presenting the maximum accumulation value of 91.7 ng·g-1 due to feeding uptake. After the depletion phase on day 13, the value found was 0.83 ng·g-1. The bioconcentration factor calculated was 20 L·kg-1. After the bioaccumulation period, the concentrations of SDZ in the water and excreta were 4.5 µg·L-1 and 363.5 ng·g-1, respectively. In the depletion period, the concentrations in the water and excreta were 0.01 µg·L-1 and 5.96 ng·g-1, respectively. These results imply that there was little SDZ bioaccumulation in the fish, but that it was distributed in larger amounts in the water. This is due to the physicochemical properties of the molecule with the low Log P value. Regarding the maximum residue limit, the value was below the established value. This study contributes to understanding SDZ dynamics in an aquatic species native to Brazil.

Nuclear and morpho-histopathological alterations in Astyanax altiparanae exposed to effluent from the process of anodizing aluminum.

Aluminum is a metal widely used from household utensils to civil construction. Anodizing aluminum is a procedure to form a thick layer of aluminum oxide on the surface in order to confer greater resistance to the material. This process generates an effluent with acidic pH and a high concentration of sulfate. Alternatives for the treatment of this effluent involve the use of the chemical precipitation technique, which can be used with salts of barium chloride (BaCl2), calcium chloride (CaCl2), and aluminum hydroxide with commercial limestone (Cc/Al (OH)3). The objective of this study was to evaluate the toxicity of effluents on Astyanax altiparanae (Lambari), by means of somatic, genetic, morphological, and histological markers after 24 and 96 h of exposure. After measuring the biometric data of the animals and the weight of the liver, we found that the condition factor (K) of individuals exposed to the effluent CaCl2 showed a slight reduction in growth after 96 h while the hepatosomatic index (HSI) remained unchanged for all effluents in both sampling times. The micronucleus test with erythrocytes indicated that the raw effluent (E2) induced nuclear changes after 24 h; however, this effect did not persist after 96 h of exposure. Branchial arches were collected and according to Bernet's index for histopathology, all effluents except Cc/Al (OH)3, induced significant changes in the gills. In accordance with the index of Poleksic and Mitrovic-Tutundzic, CaCl2 was the only effluent to compromise branchial operation. The branchial morphology investigated by SEM showed that the raw effluent (E1) induced injuries and compromised gill functions. This study reinforces the importance of biological tests for the assessment and validation of physical chemicals used and effluent treatment techniques as well as the development and application of biological parameters before the wastewater release, whether in a raw state or a treated one.

Attempts for increasing Astyanax altiparanae spawning rates and percentage of responsive oocytes.

In this study, we aimed to propose changes in the protocol of cultured Astyanax altiparanae hypophysation to increase the maximum ovulation rate of 60% registered previously. To that two consecutive experiments were conducted. In the first experiment, three carp pituitary homogenate (CPH) doses (3, 6, and 9 mg/kg) were administered in a single injection, while in the second experiment, the 6 mg/kg CPH dose was tested either in single or double injections. In the first experiment, a single injection of 3 mg/kg CPH did not induce final oocyte maturation or spawning, while a dose of 6 mg/kg CPH resulted in an increase in the plasma level of prostaglandin (PGF2α) at ovulation. The single higher dose of 9 mg/kg CPH did not improve reproductive performance and even though anticipated the resumption of meiosis it was detrimental to the spawning rate. In the second experiment, the dose of 6 mg/kg CPH fractionated into two injections led to a higher spawning rate, spawning volume per female body mass, frequency of post-ovulatory complexes, and PGF2α concentration at ovulation compared to the single injection. The most effective treatment remained the 6 mg/kg of CPH fractionated into two injections, but still providing very low proportion of ovulated females (∼40 %). Overall, this study indicates that the spawning protocols for this species need to be improved to induce ovulation in a larger number of females and be more potent in those females that respond positively.

New approaches concerning the testis of Astyanax lacustris (Characidae): immunohistochemical studies.

Astyanax lacustris, locally known as lambari-do-rabo-amarelo, is a study model for Neotropical fish. Testis of A. lacustris shows deep morphophysiological changes throughout the annual reproductive cycle. This work analyzed the distribution of claudin-1, actin, and cytokeratin as elements of the cytoskeleton in germinal epithelium and interstitium; the distribution of type I collagen, fibronectin, and laminin as extracellular matrix compounds; and the localization of androgen receptor in the testis of this species. Claudin-1, cytokeratin, and actin were present in the Sertoli cells and modified Sertoli cells, and actin was also detected in peritubular myoid cells. Type I collagen were in the interstitial tissue, laminin in the basement membrane of germinal epithelium and endothelium, but fibronectin was additionally detected in the germinal epithelium compartment. The labeling of androgen receptor was higher in peritubular myoid cells and undifferentiated spermatogonia, and weaker labeling was detected in type B spermatogonia. Therefore, the present work highlights new aspects of the biology of the testis of A. lacustris, and contribute to amplify the understanding of this organ.

All-triploid offspring in the yellowtail tetra Astyanax altiparanae Garutti & Britski 2000 (Teleostei, Characidae) derived from female tetraploid × male diploid crosses.

This study aimed to evaluate the ploidy and survival of larvae resulting from crosses between tetraploid females and diploid males of yellowtail tetra Astyanax altiparanae, both females (three diploids and three tetraploids) and males (n = 3 diploids). Breeders were subjected to hormonal induction with pituitary gland extract from common carp fish (Cyprinus carpio). Females received two doses at concentrations of 0.3 and 3.0 mg/kg -1 body weight and at intervals of 6 h. Males were induced with a single dose of 3.0 mg/kg -1 applied simultaneously with the second dose in females. Oocytes from each diploid and tetraploid female were fertilized with semen from the same male, resulting in two crosses: cross 1 (diploid male and diploid female) and cross 2 (diploid male and tetraploid female). The procedures were performed with separate females (diploid and tetraploid) and diploid males for each repetition (n = 3). For ploidy determination, 60 larvae from each treatment were analyzed using flow cytometry and cytogenetic analyses. As expected, flow cytometry analysis showed that progenies from crosses 1 and 2 presented diploid and triploid individuals, respectively, with a 100% success rate. The same results were confirmed in the cytogenetic analysis, in which the larvae resulting from cross 1 had 50 metaphase chromosomes and those from cross 2 had 75 chromosomes. The oocytes have a slightly ovoid shape at the time of extrusion. Diploid oocytes had a size of 559 ± 20.62 µm and tetraploid of 1025.33 ± 30.91 µm. Statistical differences were observed between eggs from crosses 1 and 2 (P = 0.0130). No significant differences between treatments were observed for survival at the 2-cell stage (P = 0.6174), blastula (P = 0.9717), gastrula (P = 0.5301), somite (P = 0.3811), and hatching (P = 0.0984) stages. In conclusion, our results showed that tetraploid females of the yellowtail tetra A. altiparanae are fertile, present viable gametes after stripping and fertilization using the 'dry method', and may be used for mass production of triploids. This is the first report of these procedures within neotropical characins, and which can be applied in other related species of economic importance.

Autochthonous and allochthonous lactic acid bacteria: action on the hematological and intestinal microbiota for two species of Astyanax genus.

The objective of this work was to evaluate the effect of autochthonous and allochthonous lactic acid bacteria (LAB) in two species of lambaris (Astyanax bimaculatus and Astyanax fasciatus), and to investigate the effects on intestinal microbiota and hematological changes. Two experiments were carried out, one for each lambari species, both assays were divided into three treatments: autochthonous LAB, allochthonous LAB and control. The 10% inoculum was included on diet in the LAB treatments and sterile medium for control. After 30 days for A. bimaculatus LAB indigenous changes all bacteria groups analyzed, while allochthonous LAB just decrease Staphylococcus spp. count. Though for A. fasciatus his autochthone LAB reduced the staphylococcal count. In hematology, for A. bimaculatus autochthonous LAB showed a higher number of thrombocytes, lymphocytes, monocytes and total leukocytes in the circulatory system than the control. Though for A. fasciatus his autochthone LAB showed a higher number of total lymphocytes and leukocytes than the control, while Lactobacillus sp. acting as an allochthone, it did not differ among treatments. In conclusion, both LAB (Lactobacillus sp. and L. lactis) promoted more beneficial changes in the microbiota and hematological profile when they act as an autochthone probiotic, demonstrating a probiotic-associated host.

Can high- and low-temperature thermal stress modulate the antioxidant defense response of Astyanax lacustris brain?

Change in temperature of aquatic environment have impacts on the physiology of fish, especially in the brain, which is a vital organ and prone to oxidative damage. Astyanax lacustris is a freshwater fish that play an important role in the food market and has been increasingly used in fish farms, besides environmental monitoring studies. Therefore, this study aimed to evaluate the responses of antioxidant biomarkers and products of the oxidative process in the brains A. lacustris subjected to thermal shock. The specimens were obtained from artificial farming lakes and subjected to shock induced by exposure to high (31 °C ± 0.5) and low (15 °C ± 0.5) temperature for 2, 6, 12, 24, 48, 72 and 96 h; control group were maintained at 23 °C ± 0.5. At 31 °C, glutathione-related enzymes were more responsive, suggested by the change activity of GPx and G6PDH enzymes, in addition to GSH levels. At 15 °C, enzymes of the first line of defense were more active, evidenced by the change CAT activity. No significant changes were detected in the levels of ROS, LPO and PCO. These results indicate that the brains of A. lacustris have an efficient antioxidant defense system with the ability to acclimatize to the temperatures tested.

Metformin-induced alterations in gills of the freshwater fish Astyanax lacustris (Lütken, 1875) detected by histological and scanning electron microscopy.

The antidiabetic drug metformin is widely prescribed and found in different concentrations in the environment around the world, raising concern about potential impacts on aquatic life. Analyses of the effects of exposure of biological models to aquatic contaminants are important for assessing pollution effects on fish health. The gills of fishes represent primary targets of disturbance by pollutants, mainly because of the large surface of the respiratory epithelium and the high perfusion rate, which both help the entry of pollutants into this tissue. In this context, the aim of this work was to use gill histological analyses biomarkers to evaluate the toxicity of metformin on aquatic environmental systems, by means of chronic exposure for 90 days of Astyanax lacustris (lambari), an ecologically important neotropical species that can be used as an environmental bioindicator. Histopathological analyses were performed using Light and Scanning Electron Microscopy. The main changes were lamellar fusion, telangiectasia hyperplasia and disappearance of microridges. The morphological changes observed possibly interfere with the gill physiology, indicating an unfavorable situation to the presence of metformin in the water, pointing to a concern that metformin may pose a risk to Astyanax lacustris and likely to other fish species, compromising the dynamics of the aquatic ecosystem as a whole. Graphical abstract.

A new species of Tiddergasilus Marques & Boeger, 2018 (Copepoda: Ergasilidae) from the gills of Astyanax lacustris (Lütken) (Osteichthyes: Characidae) in Brazil.

A new parasitic copepod, Tiddergasilus bipartitus n. sp. (Copepoda, Ergasilidae), is described herein based on three adult females found attached to the gills of the yellow-tail lambari Astyanax lacustris (Lütken), sampled in Pardo River, municipality of Botucatu, São Paulo State, Brazil. Tiddergasilus bipartitus n. sp. was recognized as a new member of the monotypic genus Tiddergasilus Marques & Boeger, 2018 by having: antennule 6-segmented; maxillary basis armed with 2 terminal teeth and ornamented with multiple spinules; second and third leg both with endopod 3-segmented. The new copepod can be distinguished from its congener, Tiddergasilus iheringi (Tidd, 1942), by the morphology of the antennal claw, number of somites/segments in abdomen and fourth leg, and by the ornamentation of the first leg. This report expands the geographic distribution and diversity of fish species parasitized with Tiddergasilus spp. in Brazil. Moreover, it also represents the first report of an ergasilid species in the Pardo River. A list of diagnostic features for the Brazilian species of Ergasilus von Nordmann, 1832 is provided herein, in order to aid comparisons with the species of this complex genus.

Microcystin-LR at sublethal concentrations induce rapid morphology of liver and muscle tissues in the fish species Astyanax altiparanae (Lambari).

The process of eutrophication and consequent proliferation of cyanobacteria in rivers and lakes leads to increasing numbers of harmful algal blooms and higher concentration of toxic metabolites in freshwater bodies. Microcystin is a toxic metabolite produced by cyanobacteria that is frequently detected and can pose health risks to important freshwater species including fish. The aim of the present study was to evaluate the effects of microcystin-LR on the morphology of Astyanax altiparanae's liver and muscle. One hundred (n = 100) Astyanax altiparanae were divided into 5 groups (n = 20) with 24 h and 96 h of microcystin exposition at two doses of 0.5 and 1.0 µg/L. Differences were observed in the microcystin treatment with respect to histopathological analyses including cytoplastic degradation, displacement, and increase in nuclei volume and area of hepatocytes. Hyperemia and dilation of blood capillaries were seen in the liver. There were also observable changes in the size of muscle fibers and muscle inflammation. Our results demonstrate that microcystins can impact the integrity of both tissues even at sublethal concentrations. Low doses of microcystins are therefore sufficient to intoxicate fish livers and muscle tissues.

Seasonality effects on the metal concentration and biochemical changes in Astyanax lacustris (Teleostei: Characiformes) from Doce River after the collapse of the Fundão dam in Mariana, Brazil.

This study aimed to evaluate the harmful effects of metal accumulation on Astyanax lacustris and their biochemical response when exposed to the metals contained in the Doce River water, Brazil. The study was carried out in the Baixo Guandu region of the Doce River, Espírito Santo state. Samples were collected during the dry and wet seasons. Biochemical alterations were observed in the liver of A. lacustris, with apparent seasonal effects directly related to the high concentration of Al and Fe in this tissue. Despite this, the bioconcentration of metals in the organisms showed seasonal effects only in the gills, as they are the first organ in contact with the contaminated water. The data generated in this study provide an overview of the health of the ecosystem in this region, highlighting the harmful biochemical and metal concentration effects on the population of A. lacustris affected by the Fundão dam failure.

Revisão taxonômica de Psalidodon eigenmanniorum (Cope) com base em análises morfométrica, merística e padrão de colorido (Characiformes: Characidae) / Taxonomic review of Psalidodon eigenmanniorum (Cope) based on morphometric and meristic analysis and color pattern (Characiformes: Characidae)

A identidade de Psalidodon eigenmanniorum (Cope, 1894) e a possibilidade de se constituir em mais de uma espécie é testada através de análises da morfometria (19 medidas), dos caracteres merísticos (14 contagens) e do padrão de colorido de 705 exemplares provenientes dos sistemas dos rios Tramandaí/Mampituba, da laguna dos Patos e drenagem do baixo rio Uruguai. Foram diafanizados e corados 40 exemplares. Os dados morfométricos foram utilizados na Análise de Componentes Principais, Análise Discriminante, Morfometria Geométrica e Função Discriminante. As análises foram feitas considerando os sexos em separado dentro de cada sistema hidrográfico, bem como comparando as populações entre os sistemas hidrográficos e finalmente no conjunto de sistemas representando a área de ocorrência da espécie. A partir dos dados analisados não foram encontradas diferenças entre os sexos. Os resultados mostraram variação morfológica que não sustenta o reconhecimento de possíveis espécies crípticas. A variação encontrada nos dados merísticos, morfométricos e no padrão de colorido justifica a redescrição da espécie. Os resultados das comparações entre as populações indicaram variações nesses caracteres indicando que a espécie possui considerável plasticidade fenotípica.(AU)

The identity of Psalidodon eigenmanniorum (Cope, 1894) and the possibility of constituting more than one species is tested through analyzes of morphometry (19 measurements), meristic characters (14 counts) and the color pattern of 705 specimens from the Tramandaí/Mampituba, from the Patos lagoon and from the lower Uruguay River drainage. Forty specimens were cleared and stained. Morphometric data were used in Principal Component Analysis, Discriminant Analysis, Geometric Morphometry and Discriminant Function. The analysis was carried out considering the sexes separately within each hydrographic system, as well as comparing the populations between the hydrographic systems and finally in the set of systems representing the area of occurrence of the species. No differences were found between the sexes in the analyzed data. The results showed morphological variation that does not support the recognition of possible cryptic species. The variation found in meristic, morphometric and color pattern data justifies the redescription of the species. The species is described to the aforementioned drainages, and the results demonstrate its phenotypic plasticity.(AU)

Seasonality and forest edge as drivers of Tradescantia zebrina Hort. ex Bosse invasion in the Atlantic Forest / Sazonalidade e efeito de borda florestal como direcionadores da invasão de Tradescantia zebrina Hort. ex Bosse na Mata Atlântica

As a result of biodiversity and ecosystem service losses associated with biological invasions, there has been growing interest in basic and applied research on invasive species aiming to improve management strategies. Tradescantia zebrina is a herbaceous species increasingly reported as invasive in the understory of disturbed forest ecosystems. In this study, we assess the effect of spatial and seasonal variation on biological attributes of this species in the Atlantic Forest. To this end, we measured attributes of T. zebrina associated with plant growth and stress in the four seasons at the forest edge and in the forest interior of invaded sites in the Iguaçu National Park, Southern Brazil. The invasive plant had higher growth at the forest edge than in the forest interior and lower leaf asymmetry and herbivory in the winter than in the summer. Our findings suggest that the forest edge environment favours the growth of T. zebrina. This invasive species is highly competitive in the understory of semi-deciduous seasonal forests all over the year. Our study contributes to the management of T. zebrina by showing that the summer is the best season for controlling this species.

As perdas de biodiversidade e os seus serviços ecossistêmicos ocasionadas pelas invasões biológicas, têm despertado o interesse em pesquisas básicas e aplicadas sobre as espécies invasoras com o objetivo de buscar estratégias de manejo. Tradescantia zebrina é uma das herbáceas crescentemente relatadas como uma invasora no sub-bosque florestal de ecossistemas impactados. Neste estudo, nós estudamos o efeito da variação espacial e sazonal sobre atributos biológicos desta espécie na Floresta Atlântica. Assim, nós mensuramos atributos de T. zebrina associados com o crescimento vegetal e o estresse nas quatro estações do ano em borda e interior da floresta de locais invadidos no Parque Nacional do Iguaçu, Sul do Brasil. A planta invasora apresentou maior crescimento na borda florestal do que no interior. Adicionalmente, assimetria foliar e herbivoria obtidos no inverno foram menores quando comparados ao verão. Nossos achados sugerem que os ambientes de borda florestal favorecem o crescimento de T. zebrina. Esta espécie invasora é altamente competitiva no sub-bosque da Floresta Estacional Semidecídua durante o ano todo. Nosso estudo contribui com o manejo de T. zebrina mostrando que o verão é a melhor estação para o controle desta espécie.

Seasonality and forest edge as drivers of Tradescantia zebrina Hort. ex Bosse invasion in the Atlantic Forest

Abstract As a result of biodiversity and ecosystem service losses associated with biological invasions, there has been growing interest in basic and applied research on invasive species aiming to improve management strategies. Tradescantia zebrina is a herbaceous species increasingly reported as invasive in the understory of disturbed forest ecosystems. In this study, we assess the effect of spatial and seasonal variation on biological attributes of this species in the Atlantic Forest. To this end, we measured attributes of T. zebrina associated with plant growth and stress in the four seasons at the forest edge and in the forest interior of invaded sites in the Iguaçu National Park, Southern Brazil. The invasive plant had higher growth at the forest edge than in the forest interior and lower leaf asymmetry and herbivory in the winter than in the summer. Our findings suggest that the forest edge environment favours the growth of T. zebrina. This invasive species is highly competitive in the understory of semi-deciduous seasonal forests all over the year. Our study contributes to the management of T. zebrina by showing that the summer is the best season for controlling this species.

Resumo As perdas de biodiversidade e os seus serviços ecossistêmicos ocasionadas pelas invasões biológicas, têm despertado o interesse em pesquisas básicas e aplicadas sobre as espécies invasoras com o objetivo de buscar estratégias de manejo. Tradescantia zebrina é uma das herbáceas crescentemente relatadas como uma invasora no sub-bosque florestal de ecossistemas impactados. Neste estudo, nós estudamos o efeito da variação espacial e sazonal sobre atributos biológicos desta espécie na Floresta Atlântica. Assim, nós mensuramos atributos de T. zebrina associados com o crescimento vegetal e o estresse nas quatro estações do ano em borda e interior da floresta de locais invadidos no Parque Nacional do Iguaçu, Sul do Brasil. A planta invasora apresentou maior crescimento na borda florestal do que no interior. Adicionalmente, assimetria foliar e herbivoria obtidos no inverno foram menores quando comparados ao verão. Nossos achados sugerem que os ambientes de borda florestal favorecem o crescimento de T. zebrina. Esta espécie invasora é altamente competitiva no sub-bosque da Floresta Estacional Semidecídua durante o ano todo. Nosso estudo contribui com o manejo de T. zebrina mostrando que o verão é a melhor estação para o controle desta espécie.

Seasonality and forest edge as drivers of Tradescantia zebrina Hort. ex Bosse invasion in the Atlantic Forest / Sazonalidade e efeito de borda florestal como direcionadores da invasão de Tradescantia zebrina Hort. ex Bosse na Mata Atlântica

As a result of biodiversity and ecosystem service losses associated with biological invasions, there has been growing interest in basic and applied research on invasive species aiming to improve management strategies. Tradescantia zebrine is a herbaceous species increasingly reported as invasive in the understory of disturbed forest ecosystems. In this study, we assess the effect of spatial and seasonal variation on biological attributes of this species in the Atlantic Forest. To this end, we measured attributes of T. zebrina associated with plant growth and stress in the four seasons at the forest edge and in the forest interior of invaded sites in the Iguaçu National Park, Southern Brazil. The invasive plant had higher growth at the forest edge than in the forest interior and lower leaf asymmetry and herbivory in the winter than in the summer. Our findings suggest that the forest edge environment favours the growth of T. zebrina. This invasive species is highly competitive in the understory of semi-deciduous seasonal forests all over the year. Our study contributes to the management of T. zebrina by showing that the summer is the best season for controlling this species.

As perdas de biodiversidade e os seus serviços ecossistêmicos ocasionadas pelas invasões biológicas, têm despertado o interesse em pesquisas básicas e aplicadas sobre as espécies invasoras com o objetivo de buscar estratégias de manejo. Tradescantia zebrina é uma das herbáceas crescentemente relatadas como uma invasora no sub-bosque florestal de ecossistemas impactados. Neste estudo, nós estudamos o efeito da variação espacial e sazonal sobre atributos biológicos desta espécie na Floresta Atlântica. Assim, nós mensuramos atributos de T. zebrina associados com o crescimento vegetal e o estresse nas quatro estações do ano em borda e interior da floresta de locais invadidos no Parque Nacional do Iguaçu, Sul do Brasil. A planta invasora apresentou maior crescimento na borda florestal do que no interior. Adicionalmente, assimetria foliar e herbivoria obtidos no inverno foram menores quando comparados ao verão. Nossos achados sugerem que os ambientes de borda florestal favorecem o crescimento de T. zebrina. Esta espécie invasora é altamente competitiva no sub-bosque da Floresta Estacional Semidecídua durante o ano todo. Nosso estudo contribui com o manejo de T. zebrina mostrando que o verão é a melhor estação para o controle desta espécie.

Biomarker responses induced by bisphenol A on spermatogenesis in a Neotropical teleost fish are temperature-dependent.

Bisphenol A (BPA) is an organic synthetic compound used in the plastic industry with endocrine disrupting activity. Although it is frequently found in surface waters, few studies have investigated its impact on fish gametogenesis, particularly when associated with natural stressors. In this regard, the present study evaluated BPA toxicity on spermatogenesis in the lambari Astyanax bimaculatus under controlled conditions and its interactive effects with water temperature. Adult specimens were exposed in duplicate to 40 µg/L and 400 µg/L BPA at 23 °C and 28 °C for 21 days; the control group did not receive BPA. Testicular samples were collected and analyzed using different cellular and molecular techniques. The results showed a significant reduction in the gonadosomatic index in the BPA-treated groups at both temperatures. A decrease in the testicular levels of 11-ketotestosterone was observed in the 400 µg/L BPA group at 23 °C, 17ß-estradiol increased significantly in the treated groups at 28 °C, and vitellogenin showed no difference between the treatments. The morphometric analysis of spermatogenesis revealed a significant increase in the proportion of spermatogonia, spermatocytes, and Sertoli cells in the treated groups, with a higher proportion at 23 °C than at 28 °C. Otherwise, the proportion of spermatozoa was significantly lower in the BPA-treated groups, with a greater reduction at 23 °C. In addition, BPA also stimulated spermatogonial proliferation in the treated groups, but apoptosis was significantly increased in spermatids at 23 °C. Testis-ova, cell degeneration, and chromatin alterations in spermatids and Sertoli cells were observed in the germinal epithelium of the BPA-treated groups. The integrated biomarker response (IBR) index revealed that the analyzed endpoints are suitable for assessing estrogenic contamination. Taken together, our results indicate that the interactive effects of BPA and temperature contribute to the impairment of spermatogenesis in A. bimaculatus with more severe effects observed on sperm production at 23 °C than at 28 °C.