Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 67.684
Filtrar
1.
Environ Pollut ; 292(Pt A): 118333, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34637829

RESUMO

While interactions with global warming and multigenerational effects are considered crucial to improve risk assessment of pesticides, these have rarely been studied in an integrated way. While heat extremes can magnify pesticide toxicity, no studies tested how their combined effects may transmit to the next generation. We exposed mosquito larvae in a full factorial, two-generation experiment to a heat spike followed by chlorpyrifos exposure. As expected, the heat spike magnified the chlorpyrifos-induced lethal and sublethal effects within both generations. Only when preceded by the heat spike, chlorpyrifos increased mortality and reduced the population growth rate. Moreover, chlorpyrifos-induced reductions in heat tolerance (CTmax), acetylcholinesterase (AChE) activity and development time were further magnified by the heat spike. Notably, when parents were exposed to chlorpyrifos, the chlorpyrifos-induced lethal and sublethal effects in the offspring were smaller, indicating increased tolerance to chlorpyrifos. In contrast, there was no such multigenerational effect for the heat spike. Despite the adaptive multigenerational effect to the pesticide, the synergism with the heat spike was still present in the offspring generation. Generally, our results provide important evidence that short exposure to pulse-like global change stressors can strongly affect organisms within and across generations, and highlight the importance of considering multigenerational effects in risk assessment.


Assuntos
Clorpirifos , Culicidae , Praguicidas , Acetilcolinesterase , Animais , Clorpirifos/toxicidade , Temperatura Alta , Larva
2.
Chemosphere ; 287(Pt 1): 132063, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34523442

RESUMO

Plastic waste has been considered a serious global environmental problem for decades. Despite the high recalcitrance of synthetic plastics, the biodegradation of polyethylene (PE), polystyrene (PS), polypropylene (PP), and polyvinyl chloride (PVC) by some insect larvae has been reported; however, the mechanism of degradation remains largely unknown. We investigated the effects of plastics on the growth of mealworms (larvae of Tenebrio molitor) and their role in PS and PE degradation. Mealworms were capable of ingesting high-impact polystyrene (HIPS), expanded polystyrene (EPS) and low-density polyethylene (LDPE) but not linear low-density polyethylene (LLDPE) or polypropylene (PP). Plastic consumption was negatively dependent on plastic crystallinity. Transcriptome analysis and KEGG mapping revealed that mealworms act as downstream decomposers in plastic depolymerization and that fatty acid degradation pathways may play important roles in the digestion of plastic degradation intermediates produced by gut bacteria. In addition, PS and PE degradation was achieved via the diffusion of extracellular depolymerases, which probably acted on the distal backbone and produce shorter linear chains that containing ≤16 C atoms instead of branched chains. Additionally, the intermediates of PS degradation are expected to be further decomposed by mealworms as xenobiotics. This study provided a preliminary understanding of plastic degradation mechanism by mealworms.


Assuntos
Tenebrio , Animais , Larva , Plásticos , Poliestirenos , Transcriptoma
3.
Chemosphere ; 287(Pt 1): 132120, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34523462

RESUMO

Water environmental pollution caused by spent batteries is a nonignorable environmental issue. In this study, the early life stage of zebrafish was employed to assess the environmental risk of spent batteries after exposure to 0, 1%, 2%, 5% and 10% spent battery extract for 120 h. Our results clearly indicated that spent battery extract can significantly decrease the survival rate, hatching rate and body length and increase heart rate. Moreover, spent battery extract exposure-induced zebrafish larvae generate oxidative stress and inhibit the mRNA transcriptional levels of heat shock protein (HSP70) and metallothionein (MT) genes. These results showed that the spent batteries not only affected the survival and development performance of zebrafish at an early life stage but also caused oxidative stress and interfered with the detoxification of zebrafish. This study provided novel insight into spent battery induced toxicity in the early life stage of fish.


Assuntos
Poluentes Químicos da Água , Peixe-Zebra , Animais , Biomarcadores/metabolismo , Embrião não Mamífero/metabolismo , Larva , Estresse Oxidativo , Extratos Vegetais , Poluentes Químicos da Água/metabolismo , Poluentes Químicos da Água/toxicidade
4.
Sci Total Environ ; 802: 149938, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34525687

RESUMO

Deltamethrin (DM), a type II pyrethroid insecticide, is widely used to control agricultural pests. However, its excessive use exerts a detrimental effect on the ecological environment and human health, indicating the need to study its potential risks in detail. In the present study, zebrafish embryos were exposed to varying concentrations of DM (0.1, 1, 10, and 25 µg/L) for 96 h to assess the alterations in the transcript levels of proteins of the estrogenic and dopaminergic pathways. In addition, its effect on zebrafish locomotor activity was studied. The mRNA expression of cyp19a1b, erα, erß2, fshr, gnrh2, gnrhr3, vtg3, dat, and dr1 significantly changed after exposing the embryos to DM. Deltamethrin at 10 and 25 µg/L significantly reduced the average swimming speed of zebrafish larvae. In addition, embryos injected with zebrafish estrogen receptor α (erα) and ß (erß) morpholinos and co-exposed to 25 µg/L DM for 96 h showed reduced expression of vtg3 mRNA compared to embryos exposed to 25 µg/L DM only. The locomotor activity of erα and erß knockdown zebrafish following DM exposure was increased significantly when compared with that of larvae exposed to 25 µg/L DM only. Our results demonstrated that DM altered the locomotor activity of zebrafish larvae and the transcript levels of the components of estrogenic and dopaminergic pathways; erα and erß knockdown weakened these effects.


Assuntos
Piretrinas , Peixe-Zebra , Animais , Embrião não Mamífero , Humanos , Larva , Nitrilas , Piretrinas/toxicidade , Receptores de Estrogênio/genética
5.
Chemosphere ; 286(Pt 3): 131866, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34391112

RESUMO

Tralopyril (TP), an antifouling biocide, is widely used to prevent heavy biofouling, and can have potential risks to aquatic organisms. In this study, the effect of TP on locomotor activity and related mechanisms were evaluated in zebrafish (Danio rerio) larvae. TP significantly reduced locomotor activity after 168 -h exposure. Adverse modifications in tail muscle tissue, the nervous system, and energy metabolism were also observed in larvae. TP caused thinning of the muscle bundle in the tail of larvae. In conjunction with the metabolomics results, changes in dopamine (DA) and acetylcholine (ACh), acetylcholinesterase (AChE) activity, and the expression of genes involved in neurodevelopment, indicate that TP may disrupt the nervous system in zebrafish larvae. The change in metabolites (e.g., glucose 6-phosphate, cis-Aconitic acid, acetoacetyl-CoA, coenzyme-A and 3-Oxohexanoyl-CoA) involved in carbohydrate and lipid metabolism indicates that TP may disrupt energy metabolism. TP exposure may inhibit the locomotor activity of zebrafish larvae by impairing tail muscle tissue, the nervous system, and energy metabolism.


Assuntos
Poluentes Químicos da Água , Peixe-Zebra , Acetilcolinesterase , Animais , Metabolismo Energético , Larva , Locomoção , Músculos , Sistema Nervoso , Pirróis , Poluentes Químicos da Água/toxicidade
6.
Chemosphere ; 286(Pt 2): 131719, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34426126

RESUMO

Graphene oxide (GO) has become a topic of increasing concern for its environmental and health risks. However, studies on the potential toxic effects of GO, especially as an endocrine disrupting chemical (EDC), are very limited. In the present study we have used Japanese medaka fish as a model to assess the endocrine disruption potential of GO by evaluating its toxic and histopathologic effects on thyroid follicles and the gas gland (GG) of medaka larvae. One day post-hatch (dph) starved medaka fries were exposed to GO (2.5, 5.0, 10.0, and 20 mg/L) for 96 h, followed by 6 weeks depuration in a GO-free environment with feeding. Larvae were sacrificed and histopathological evaluation of thyroid follicles and the GG cells were done microscopically. Different sizes of spherical/oval shape thyroid follicles containing PAS positive colloids, surrounded by single-layered squamous/cuboidal epithelium, were found to be scattered predominantly throughout the pharyngeal region near the ventral aorta. We have apparently observed a sex-specific difference in the follicular size and thyrocytes height and a non-linear effect of GO exposure on the larvae on 47th day post hatch (dph). The GG is composed of large uniform epithelial cells with eosinophilic cytoplasm. Like thyroids, our studies on GG cells indicate a sex-specific difference and GO exposure non-linearly reduced the GG cell numbers in males and females as well as in XY and XX genotypes. Our data further confirm that sex effect should be carefully considered while assessing the toxicity of EDCs on the thyroid gland.


Assuntos
Oryzias , Poluentes Químicos da Água , Animais , Epitélio , Feminino , Grafite , Larva , Masculino , Glândula Tireoide
7.
Environ Pollut ; 292(Pt B): 118441, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34728326

RESUMO

Across the planet, winter de-icing practices have caused secondary salinization of freshwater habitats. Many amphibians are vulnerable because of permeable skin and reliance on small ponds, where salinity can be high. Early developmental stages of amphibians are especially sensitive to salt, and larvae developing in salt-polluted environments must osmoregulate through ion exchange in gills. Though ionoregulation in amphibian gills is generally understood, the role of gill morphology remains poorly described. Yet gill structure should affect ionoregulatory capacity, for instance in terms of available surface area. As larval amphibian gills also play critical roles in gas exchange and foraging, changes in gill morphology from salt pollution potentially affect not only osmoregulation, but also respiration and feeding. Here, we used an exposure experiment to quantify salinity effects on larval gill morphology in wood frogs (Rana sylvatica). We measured a suite of morphological traits on gill tufts-where ionoregulation and gas exchange occur-and on gill filters used in feeding. Larvae raised in elevated salinity developed larger gill tufts but with lower surface area to volume ratio. Epithelial cells on these tufts were less circular but occurred at higher densities. Gill filters showed increased spacing, likely reducing feeding efficiency. Many morphological gill traits responded quadratically, suggesting that salinity might induce plasticity in gills at intermediate concentrations until energetic demands exceed plasticity. Together, these changes likely diminish ionoregulatory and respiratory functionality of gill tufts, and compromise feeding functionality of gill filters. Thus, a singular change in aquatic environment from a widespread pollutant appears to generate a suite of consequences via changes in gill morphology. Critically, these changes in traits likely compound the severity of fitness impacts in populations dwelling in salinized environments, whereby ionoregulatory energetic demands should increase respiratory and foraging demands, but in individuals who possess structures poorly adapted for these functions.


Assuntos
Brânquias , Cloreto de Sódio , Animais , Humanos , Larva , Osmorregulação , Ranidae
8.
Parasitol Int ; 86: 102473, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34600157

RESUMO

Despite the large number of species described to date for the onchoprotepcephalid genus Acanthobothrium (207), only 16 named species have a genetic sequence. With this background, specimens of adult cestodes of the stingray Hypanus longus were collected off San Blas, Nayarit, and onchoproteocephalid larvae in the carangid fish Trachinotus rhodopus from Puerto Ángel, Oaxaca, both located on the Pacific coast of Mexico. The objective of this work is to investigate the phylogenetic position of these adults and larvae using nuclear ribosomal markers (18S rDNA and 28S rDNA). Morphologically, adult specimens were identified as Acanthobothrium cleofanus; larvae were identified only to family level. The phylogenetic position of both taxa was investigated based on the information of two nuclear molecular markers analyzed under Parsimony (PA) and Bayesian Inference (BI) methods. The newly generated sequences of A. cleofanus from Nayarit are identical to the sequences of several samples of Acanthobothrium sp. collected in the Mexican Pacific, which sequence are available in GenBank; DNA sequences obtained from onchoproteocephalid larva clearly place this taxon within Acanthobothrium but representing an independent lineage. In the resulting phylogenetic trees, Uncibilocularis okei was found nested within Acanthobothrium with an unstable position depending on the optimality criteria, indicating the need for more molecular analyzes with a greater number of species of both genera prior to define its phylogenetic relationships.


Assuntos
Cestoides/classificação , Infecções por Cestoides/veterinária , Doenças dos Peixes/parasitologia , Rajidae , Animais , Cestoides/genética , Cestoides/crescimento & desenvolvimento , Infecções por Cestoides/parasitologia , Marcadores Genéticos , Larva/classificação , Larva/crescimento & desenvolvimento , México , Filogenia , RNA Ribossômico 18S/análise , RNA Ribossômico 28S/análise
9.
Parasitol Int ; 86: 102449, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34481946

RESUMO

Trichinellosis is a potentially deadly parasitic zoonosis that is contracted by consuming undercooked infected meat. Reliable detection of infectious Trichinella spp. larvae in meat is therefore pivotal to ensure consumer's safety. The recently authorised PrioCHECK™ Trichinella Alternative Artificial Digestion (AAD) test kit appears promising when used with the standard magnetic stirrer method, but evaluation with other apparatus types is lacking. In this study, the performance of the AAD kit in an adapted Trichomatic-35 (TM35) instrument was evaluated, first, at the Swiss National Reference Laboratory for trichinellosis (NRL); second, in a ring trial involving four Swiss official laboratories. Proficiency pork samples spiked with larvae of Trichinella spiralis, T. britovi, or T. pseudospiralis were tested with the AAD kit and with the reference pepsin-HCl digestion method in TM35 instruments. At the NRL, both methods yielded identical qualitative and similar quantitative results independently of the Trichinella species. In the ring trial, satisfactory results were obtained for 47/50 (94.0%) (AAD) and 62/67 (92.5%) (reference method) of the analysed samples. Technical problems impairing analysis were more frequently observed with the AAD kit (n = 22) than with the reference method (n = 5) and were mainly (16/22) reported by one of the external labs. When no technical issues were recorded, the performance of both methods was comparable, in agreement with the observations at the NRL; however, these results suggest a need for further training with the kit and standardisation of the adapted TM35 instruments.


Assuntos
Testes Diagnósticos de Rotina/instrumentação , Parasitologia de Alimentos , Carne de Porco/parasitologia , Trichinella/isolamento & purificação , Animais , Larva/crescimento & desenvolvimento , Sensibilidade e Especificidade , Trichinella/crescimento & desenvolvimento , Trichinella spiralis/crescimento & desenvolvimento , Trichinella spiralis/isolamento & purificação
10.
Sci Total Environ ; 804: 149920, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34509837

RESUMO

Enormous production of cosmetic products and its indiscriminate use tends to discharge into the aquatic environment and might threaten non-target organisms inhabiting aquatic ecosystems. In the present study, developmental toxicity of 4-methylbenzylidene camphor (4-MBC), a widely used organic UV filter in personal care products has been evaluated using zebrafish embryo-larval stages. Waterborne exposure induced developmental toxicity and deduced 2.71 mg/L as 96 h LC50 whereas embryos exposed to sub-lethal concentrations (50 and 500 µg/L) caused a significant delay in hatching rate, heart rate, reduced larval length, and restricted hatchlings motility besides the axial curvature. Chronic exposure to 10 dpf resulted in significant decrease in SOD activity at 500 µg/L with no changes in CAT level besides a significant increase in GST enzyme at 5 µg/L concentration in 5 dpf sampled larvae. However, all the three enzymes were significantly elevated in 10 dpf larvae indicating differential oxidative stress during the stages of development. Similar trend is noticed for acetylcholine esterase enzyme activity. A concentration dependent increase in malondialdehyde content was noted in larvae sampled at 5 and 10 dpf. In addition, multixenobiotic resistance (MXR) activity inhibition, and elevated oxidative tissue damage were noticed at 5 dpf with no significant changes in 10 dpf larvae. Furthermore, immunoblot analysis confirms 4-MBC induced apoptosis in zebrafish larvae with promoted cleaved Caspase-3, Bax and inhibited Bcl-2 proteins expression. Subsequently, docking studies revealed the binding potential of 4-MBC to zebrafish Abcb4 and CYP450 8A1 proteins with the binding energy of -8.1 and -8.5 kcal/mol representing target proteins interaction and toxicity potentiation. Our results showed that 4-MBC exposure triggers oxidative stress at sub-lethal concentrations leading to apoptosis, deformities and locomotion perturbations in developing zebrafish.This is first of its kind in systematically demonstrating developmental toxicity of 4-MBC and the information shall be used for aquatic toxicity risk assessment.


Assuntos
Poluentes Químicos da Água , Peixe-Zebra , Animais , Cânfora/análogos & derivados , Ecossistema , Embrião não Mamífero , Larva , Estresse Oxidativo , Poluentes Químicos da Água/toxicidade
11.
Sci Total Environ ; 804: 150185, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34509844

RESUMO

Lead induced neurotoxicity has been extensively investigated. However, the potential connections between early-life lead exposure and the frequently observed aberrant neurobehavior in juveniles and adults remain unclear. In this study, zebrafish model was used to explore the immediate and long-term effects of early-life exposure to environmental levels of lead on the central nervous system, and the cellular and molecular mechanisms underlying the consequent abnormal neurobehavior. Lead exposed zebrafish larvae exhibited neurologic damage and defective neurobehavior. Consistent with clinical studies, despite being raised in lead-free conditions, the juvenile and adult fish experienced lead exposure earlier, presented ADHD-like symptoms, and the adult fish exhibited remarkably affected vitality and shoaling behavior. Their anxiety levels were elevated, whereas their social interaction, as well as learning and memory were strongly depressed. The expression profiles of key genes involved in neurodevelopment and neurotransmitter systems were significantly modulated, in similar patterns as in the larval stage. Notably, the density of neurons was decreased and varicosities in neuronal axons were frequently observed in the lead-exposed groups. It's tempting to speculate that the disruption of early neurodevelopment as well as the prolonged modulation of neuromorphic and neurotransmitter systems contribute to the lead-induced neurobehavioral disorders observed in juveniles and adulthood.


Assuntos
Chumbo , Peixe-Zebra , Animais , Sistema Nervoso Central , Larva , Chumbo/toxicidade
12.
Sci Total Environ ; 804: 150050, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34509851

RESUMO

Fish larvae play an important structuring role for their prey and show ontogenetic shifts in diet. Changes in diet differ between species and habitats and may also be affected by turbidity (eutrophication). We investigated the diet (stomach content) and the food selection (ratio of ingested prey and prey availability) of roach and perch larvae in a clear lake and of roach, perch and pikeperch larvae in a turbid lake multiple times during spring to autumn. The diet of the fish larvae changed with size, and for roach and perch larvae between the lakes. Coexisting species of fish larvae had different diets in the two lakes, pointing to resource partitioning; yet, in the clear lake, medium-sized larvae had a high diet overlap, suggesting a competitive relationship at this developmental stage. In the clear lake, roach larvae showed diel differentiation in diet, while perch demonstrated diet shifts between habitats, which probably aided in reducing competition and also evidenced an effect of light on the larval prey capture and/or predator-fish larvae interactions. In the turbid lake, roach and perch larvae did not reveal differences in diet between habitats or time of the day, owing to homogeneity of food items and poor light conditions. However, the diet of pikeperch larvae differed between day and night following daily variations in the abundance of its preferred prey. The roach larvae were highly selective for Bosmina, Daphnia and benthic cladocerans, perch larvae generally consumed what was available, while pikeperch primarily preyed on cyclopoid copepodites. We conclude that turbidity acted as a cover for fish larvae in the turbid lake. Under eutrophication-induced turbidity scenarios the effects of fish larvae on their prey are stronger (i.e., high selectivity for several resources) than that of larvae in clear waters, creating a negative feedback on the path to restore water clarity.


Assuntos
Lagos , Percas , Animais , Dieta , Preferências Alimentares , Larva , Água
13.
Sci Total Environ ; 804: 150177, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34520929

RESUMO

The effects of glyphosate (GLY)-based and glufosinate ammonium (GA)-based herbicides (GBH and GABH, respectively) and polyethylene microplastic particles (PEMPs) on Scinax squalirostris tadpoles were assessed. Tadpoles were exposed to nominal concentrations of both herbicides (from 1.56 to 100 mg L-1) and PEMPs (60 mg L-1), either alone or in combination, and toxicity evaluated at 48 h. Acetylcholinesterase (AChE), carboxylesterase (CbE), and glutathione-S-transferase (GST) activities were analyzed at the three lowest concentrations (1.56, 3.12 and 6.25 mg L-1, survival rates >85%) of both herbicides alone and with PEMPs. Additionally, the thermochemistry of the interactions between the herbicides and polyethylene (PE) was analyzed by Density Functional Theory (DFT). The median-lethal concentration (LC50) was 43.53 mg L-1 for GBH, 38.56 mg L-1 for GBH + PEMPs, 7.69 for GABH, and 6.25 mg L-1 for GABH+PEMPs. The PEMP treatment increased GST but decreased CbE activity, whereas GBH and GABH treatments increased GST but decreased AChE activity. In general, the mixture of herbicides with PEMPs increased the effect observed in the individual treatments: the highest concentration of GBH + PEMPs increased GST activity, whereas GABH+PEMP treatments decreased both AChE and CbE activities. DFT analysis revealed spontaneous interactions between the herbicides and PE, leading to the formation of bonds at the herbicide-PE interface, significantly stronger for GA than for GLY. The experimental and theoretical findings of our study indicate that these interactions may lead to an increase in toxicity when pollutants are together, meaning potential environmental risk of these combinations, especially in the case of GA.


Assuntos
Herbicidas , Poluentes Químicos da Água , Acetilcolinesterase , Aminobutiratos , Animais , Anuros , Produtos Agrícolas , Glicina/análogos & derivados , Herbicidas/toxicidade , Larva , Microplásticos , Plantas Geneticamente Modificadas , Plásticos , Poluentes Químicos da Água/toxicidade
14.
Sci Total Environ ; 805: 150210, 2022 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-34534871

RESUMO

As more and more countries have prohibited the manufacture and sale of plastic products with bisphenol A (BPA), a number of bisphenol analogues (BPs), including BPS, BPF and BPAF, have gradually been used as its primary substitutes. Ideally, substitutes used to replace chemicals with environmental risks should be inert, so it makes sense that the risk of the similar chemical substitutes (BPS, BPF, and BPAF) should be assessed before they used. Therefore, in the present study, the neurotoxicity of four BPs at environmentally relevant concentration (200 µg/L) were systematically compared using zebrafish as a model. Our results showed that the four BPs (BPA, BPS, BPF and BPAF) exhibited no obvious effect on the hatchability, survival rate and body length of zebrafish larvae, noteworthily a significant inhibitory effect on spontaneous movement at 24 hpf was observed in the BPA, BPF and BPAF treatment groups. Behavioral tests showed that BPAF, BPF and BPA exposure significantly reduced the locomotor activity of the larvae. Additionally, BPAF treatment adversely affected motor neuron axon length in transgenic lines hb9-GFP zebrafish and decreased central nervous system (CNS) neurogenesis in transgenic lines HuC-GFP zebrafish. Intriguingly, BPAF displayed the strongest effects on the levels and metabolism of neurotransmitters, followed by BPF and BPA, while BPS showed the weakest effects on neurotransmitters. In conclusion, our study deciphered that environmentally relevant concentrations of BPs exposure exhibited differential degrees of neurotoxicity, which ranked as below: BPAF > BPF ≈ BPA > BPS. The possible mechanisms can be partially ascribed to the dramatical changes of multiple neurotransmitters and the inhibitory effects on neuronal development. These results suggest that BPAF and BPF should be carefully considered as alternatives to BPA.


Assuntos
Compostos Benzidrílicos , Peixe-Zebra , Animais , Compostos Benzidrílicos/toxicidade , Larva , Fenóis/toxicidade
15.
Korean J Parasitol ; 59(5): 481-487, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34724767

RESUMO

The objective of this study was to evaluate the efficacy of an imidacloprid 10% and flumethrin 4.5% polymer matrix collar against the developmental stages of Haemaphysalis longicornis infesting dogs using the hair from treated dogs in a semi-in-vitro assay set. When incubated with 0.5 g of the hair collected from the dogs installed with the drug-embedded collar after 10 days, average death rate of the larval, nymphal, and adult H. longicornis was 21.5%, 77.9%, and 100% at 30 min, 1 hr, and 2 hr, respectively. This study showed the larval stages as well as the nymphal and adult stages of H. longicornis ticks are killed upon contact with the hair from dogs treated with the collar within 2 hr.


Assuntos
Ixodidae , Infestações por Carrapato , Animais , Cães , Imidazóis , Larva , Neonicotinoides , Nitrocompostos , Polímeros , Piretrinas , Infestações por Carrapato/veterinária
16.
J Clin Pediatr Dent ; 45(5): 341-343, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34740260

RESUMO

Myiasis is a parasitic infection of humans and animals caused by dipterous larvae and is often seen in rural areas. For the first time in the literature as a case of gingival myiasis in an 18-month-old healthy child with good oral hygiene is reported. This case presents the clinical and histopathologic features of oral myiasis. The patient had a swelling in the upper lip for three days and a perforation in the gingiva. After mechanical removal of larvae intraoral symptoms resolved within six days. The larva was identified as Wohlfahrtia magnifica according to the histopathologic evaluation. Dentists working in rural areas should be aware of this very rare condition and its treatment.


Assuntos
Gengiva , Miíase , Animais , Humanos , Lactente , Larva , Lábio , Mucosa Bucal , Miíase/diagnóstico
17.
Korean J Parasitol ; 59(5): 519-522, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34724773

RESUMO

The Chinese edible frogs, Hoplobatrachus rugulosus (n=20), and the striped snakehead fish, Channa striata (n=34), were purchased from local markets in 3 administrative regions of Cambodia (Phnom Penh, Pursat, and Takeo Provinces) from May 2017 to April 2019, and their infection status with Gnathostoma sp. larvae was investigated. The frogs and fish were transported to the laboratory with ice and examined using the artificial digestion method. Advanced 3rd-stage larvae (AdL3) of Gnathostoma spinigerum, 24 in total number (1-6 larvae/frog), were detected from 6 (60.0%) out of 10 frogs purchased from Phnom Penh. No gnathostome larvae were detected in 10 frogs purchased from Takeo Province and 34 snakeheads from Phnom Penh, Pursat, and Takeo Provinces. AdL3 isolated from the frogs were 2.55- 3.90 mm long and 0.31-0.36 mm wide. They had a characteristic head bulb (0.081×0.191 mm in average size) with 4 rows of hooklets, a muscular long esophagus (0.950-1.230 mm long), and 2 pairs of cervical sacs (0.530-0.890 mm long). The average number of hooklets in the 1st, 2nd, 3rd, and 4th rows was 41, 45, 48, and 51, respectively. These features were consistent with G. spinigerum AdL3. By the present study, it has been first confirmed that the Chinese edible frog, H. rugulosus, from Phnom Penh serves as a second intermediate host for G. spinigerum, although their intensity of infection was not so high compared to other previously reported localities.


Assuntos
Anuros/parasitologia , Gnathostoma , Animais , Camboja/epidemiologia , Larva
18.
An Acad Bras Cienc ; 93(suppl 4): e20210270, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34730623

RESUMO

Two experiments were carried out to test better stocking proportion according to animal size for tilapia (Oreochromis niloticus) and tadpole (Lithobates catesbeianus). The experiments were laid out in a completely randomized design with five treatments (in Experiment I) and four treatments (in Experiment II). In Experiment I, the treatments consisted of a tilapia monoculture; a 75% tilapia + 25% tadpole polyculture; a 50% tilapia + 50% tadpole; a 25% tilapia + 75% tadpole; and a tadpole monoculture. In Experiment II, the treatments were represented by a tilapia monoculture; a 12.5% tilapia + 87.5% tadpole polyculture; a 25% tilapia + 75% tadpole; and a tadpole monoculture. In the first trial, mortality rate differed significantly, with the polyculture treatments having almost 100% mortality of tadpoles. In the second experiment, after adjustments in the initial size of the species, there were significant differences between treatments, with the 12.5% tilapia + 87.5% tadpole polyculture and the tadpole monoculture providing the best results. Regardless of the chosen density, for a polyculture of Nile tilapia and bullfrog tadpoles, ideal conditions would be stocking tilapia fry weighing 50% of the weight initial tadpoles and the proportion of one tilapia for seven tadpoles.


Assuntos
Ciclídeos , Tilápia , Animais , Larva , Rana catesbeiana
19.
An Acad Bras Cienc ; 93(suppl 3): e20200472, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34730739

RESUMO

The present study is the first report of Spiroxys larvae parasitizing stomach and intestine of three fish species in stream of Caatinga domain, Northeast, Brazil. A total of 120 fish specimens, 40 of Astyanax bimaculatus, 40 of Hoplias malabaricus, and 40 of Hoplosternum littorale were examined for nematodes. A total of 633 specimens of Spiroxys larvae were recovered for the three fish species: 227 in A. bimaculatus (prevalence (%) = 48; mean abundance = 5.78 ± 1.78 (range = 0-70); and mean intensity = 11.95 ± 2.7 (range = 2-70)), 176 in H. malabaricus (prevalence (%) = 42.5; mean abundance = 4.40 ± 1.55 (range = 0-53); and mean intensity = 10.35 ± 2.38 (range = 2-53)) and 230 in H. littorale (prevalence (%) = 42.5; mean abundance = 5.75 ± 1.98 (range = 0-52); and mean intensity = 13.53 ± 3.04 (range = 1-52)). This study expands the range of the geographic distribution of nematodes of the genus Spiroxys and increase the list of hosts, as well as contributing to the knowledge of fish parasites biodiversity in Caatinga domain.


Assuntos
Caraciformes , Doenças dos Peixes , Nematoides , Infecções por Nematoides/veterinária , Animais , Brasil , Caraciformes/parasitologia , Doenças dos Peixes/parasitologia , Peixes , Larva
20.
Pestic Biochem Physiol ; 179: 104961, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34802511

RESUMO

As a typical glycolytic inhibitor, 3-bromopyruvate (3-BrPA) has been extensively studied in cancer therapy in recent decades. However, few studies focused on 3-BrPA in regulating the growth and development of insects, and the relationship and regulatory mechanism between glycolysis and chitin biosynthesis remain largely unknown. The Hyphantria cunea, named fall webworm, is a notorious defoliator, which caused a huge economic loss to agriculture and forestry. Here, we investigated the effects of 3-BrPA on the growth and development, glycolysis, carbohydrate homeostasis, as well as chitin synthesis in H. cunea larvae. To elucidate the action mechanism of 3-BrPA on H. cunea will provide a new insight for the control of this pest. The results showed that 3-BrPA dramatically restrained the growth and development of H. cunea larvae and resulted in larval lethality. Meanwhile, we confirmed that 3-BrPA caused a significant decrease in carbohydrate, adenosine triphosphate (ATP), pyruvic acid (PA), and triglyceride (TG) levels by inhibiting glycolysis in H. cunea larvae. Further studies indicated that 3-BrPA significantly affected the activities of hexokinase (HK), phosphofructokinase (PFK), pyruvate kinase (PK), glucose 6-phosphate dehydrogenase (G6PDH) and trehalase, as well as expressions of the genes related to glycolysis, resulting in carbohydrate homeostasis disorder. Moreover, it was found that 3-BrPA enhanced 20-hydroxyecdysone (20E) signaling by upregulating HcCYP306A1 and HcCYP314A1, two critical genes in 20E synthesis pathway, and accelerated chitin synthesis by upregulating transcriptional levels of genes in the chitin synthesis pathway in H. cunea larvae. Taken together, our findings provide a novel insight into the mechanism of glycolytic inhibitor in regulating the growth and development of insects, and lay a foundation for the potential application of glycolytic inhibitors in pest control as well.


Assuntos
Carboidratos , Glicólise , Animais , Homeostase , Larva , Piruvatos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA