Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 25.923
Filtrar
1.
An Acad Bras Cienc ; 92 Suppl 1: e20190053, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32348413

RESUMO

The yellow clam Mesodesma mactroides (Reeve, 1854) is a sand mollusc with historical and socioeconomic importance in Brazil, Uruguay and Argentina. A guaranteed form to access a successful reestablishment of the species in their natural environment is directly linked to their reproduction biology. Then, our report introduces the embryonic and larval development of the yellow clam reared in laboratory for such purposes. M. mactroides broodstock were selected as specimens who possess a mean total shell length and weight of 66 ± 3.82 mm and 27.15 ± 4.07 g for an afterwards spawn induction through stripping technique. Regarding the embryonic development, newly fertilized oocytes exhibited a mean diameter of 51.20 ± 6.64 µm. The first polar corpuscle, trochophores and D-veliger appeared at 20 min, 18 and 24 h after fertilization, respectively. Umbonate and pediveliger larvae were noticed on the 8th and 25th day, respectively, with complete metamorphosis occurring only at the 27th day, when all larvae were retained in a 200 µm nylon mesh. Therefore, with that basic understanding of the embryonic and larval development of M. mactroides in the laboratory, forwards studies will focus in establish a technological package for this species.


Assuntos
Bivalves/embriologia , Bivalves/crescimento & desenvolvimento , Animais , Bivalves/classificação , Laboratórios , Larva/crescimento & desenvolvimento , Óvulo/crescimento & desenvolvimento
3.
Ecotoxicol Environ Saf ; 193: 110312, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32109584

RESUMO

Agricultural expansion and the consequent use of pesticides lead to the loss and fragmentation of natural habitats of several wild species. Then, many species are inevitably exposed to a wide amount of pesticide formulations. Glyphosate (GLY)-based formulations are the most used herbicide, whereas two of the most employed insecticides are chlorpyrifos (CPF) and cypermethrin (CYP). The aim of this study was to evaluate genotoxicity, oxidative damage, and the modulation of antioxidants defenses in peripheral blood of Caiman latirostris after embryonic exposure to pesticide formulations and their mixtures. Pesticides concentrations employed were equivalent to those recommended in agricultural practices for application in soybean crops and a half of them: GLY: 2% and 1%; CYP: 0.12% and 0.06%; CPF: 0.8% and 0.4%. Two similar experiments (E1 and E2) were carried out in consecutive years, where C. latirostris eggs were exposed to pesticide formulations separately and in different mixtures through application on the incubation material. After hatching, blood samples were taken and genotoxicity and oxidative stress was evaluated through the micronucleus (MN) test, the modified comet assay, the lipid peroxidation (LPO) levels and the activities of catalase (CAT) and superoxide dismutase (SOD) antioxidant enzymes. The results indicated the presence of DNA damage, oxidation of purines and pyrimidines, and increased frequency of micronucleus (FMN) in the case of GLY, CYP, and CPF formulations exposure, as well as in all the mixtures tested, with respect to the control groups. Specifically, the results observed for the mixtures would indicate independent action or antagonism of the components for DNA damage and base oxidation (purines and pyrimidines) and a possible potentiation interaction for the FMN in two binary mixtures. However, there were not differences regarding lipid peroxidation, the activity of antioxidant enzymes and growth parameters. This study proved that the use of pesticide formulations at concentrations used in the field generate deleterious genetic effects on this species, then, exposure to them could threaten its survival and health status.


Assuntos
Jacarés e Crocodilos/metabolismo , Dano ao DNA , Micronúcleos com Defeito Cromossômico/induzido quimicamente , Óvulo/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Praguicidas/toxicidade , Jacarés e Crocodilos/sangue , Jacarés e Crocodilos/genética , Animais , Antioxidantes/metabolismo , Argentina , Ensaio Cometa , Peroxidação de Lipídeos/efeitos dos fármacos , Peroxidação de Lipídeos/genética , Testes para Micronúcleos , Óvulo/crescimento & desenvolvimento , Estresse Oxidativo/genética
4.
Arch Virol ; 165(4): 835-843, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32025807

RESUMO

Avian infectious bronchitis virus (IBV) is a coronavirus with great economic impact on the poultry industry, causing an acute and highly contagious disease in chickens that primarily affects the respiratory and reproductive systems. The cellular regulation of IBV pathogenesis and the host immune responses involved remain to be fully elucidated. MicroRNAs (miRNAs) have emerged as a class of crucial regulators of numerous cellular processes, including responses to viral infections. Here, we employed a high-throughput sequencing approach to analyze the miRNA composition of the spleen and the lungs of chicken embryos upon IBV infection. Compared to healthy chicken embryos, 13 and six miRNAs were upregulated in the spleen and the lungs, respectively, all predicted to influence viral transcription, cytokine production, and lymphocyte functioning. Subsequent downregulation of NFATC3, NFAT5, SPPL3, and TGFB2 genes in particular was observed only in the spleen, demonstrating the biological functionality of the miRNAs in this lymphoid organ. This is the first study that describes the modulation of miRNAs and the related host immune factors by IBV in chicken embryos. Our data provide novel insight into complex virus-host interactions and specifically highlight components that could affect the host's immune response to IBV infection.


Assuntos
Infecções por Coronavirus/veterinária , Gammacoronavirus/fisiologia , MicroRNAs/imunologia , Óvulo/virologia , Doenças das Aves Domésticas/imunologia , Animais , Galinhas , Infecções por Coronavirus/genética , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/virologia , Citocinas/genética , Citocinas/imunologia , Gammacoronavirus/genética , Pulmão/imunologia , Pulmão/patologia , MicroRNAs/genética , Óvulo/imunologia , Doenças das Aves Domésticas/genética , Doenças das Aves Domésticas/patologia , Doenças das Aves Domésticas/virologia , Baço/imunologia , Baço/patologia
5.
Arch Insect Biochem Physiol ; 103(4): e21651, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31943343

RESUMO

DNA methylation refers to the addition of cytosine residues in a CpG context (5'-cytosine-phosphate-guanine-3'). As one of the most common mechanisms of epigenetic modification, it plays a crucial role in regulating gene expression and in a diverse range of biological processes across all multicellular organisms. The relationship between temperature and DNA methylation and how it acts on the adaptability of migratory insects remain unknown. In the present work, a 5,496 bp full-length complementary DNA encoding 1,436 amino acids (named MsDnmt1) was cloned from the devastating migratory pest oriental armyworm, Mythimna separata Walker. The protein shares 36.8-84.4% identity with other insect Dnmt1 isoforms. Spatial and temporal expression analysis revealed that MsDnmt1 was highly expressed in adult stages and head tissue. The changing temperature decreased the expression of MsDnmt1 in both high and low temperature condition. Besides, we found that M. separata exhibited the shortest duration time from the last instar to pupae under 36°C environment when injected with DNA methylation inhibitor. Therefore, our data highlight a potential role for DNA methylation in thermal resistance, which help us to understand the biological role adaptability and colonization of migratory pest in various environments.


Assuntos
DNA (Citosina-5-)-Metiltransferase 1/genética , Proteínas de Insetos/genética , Mariposas/fisiologia , Sequência de Aminoácidos , Animais , Temperatura Corporal , DNA (Citosina-5-)-Metiltransferase 1/química , DNA (Citosina-5-)-Metiltransferase 1/metabolismo , Proteínas de Insetos/química , Proteínas de Insetos/metabolismo , Larva/genética , Larva/crescimento & desenvolvimento , Larva/fisiologia , Mariposas/genética , Mariposas/crescimento & desenvolvimento , Óvulo/crescimento & desenvolvimento , Óvulo/fisiologia , Filogenia , Pupa/genética , Pupa/crescimento & desenvolvimento , Pupa/fisiologia , Alinhamento de Sequência
6.
PLoS One ; 15(1): e0223396, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31995553

RESUMO

Information on the buoyancy of eggs and larvae from deep-sea species is rare but necessary for explaining the position of non-swimming larvae in the water column. Due to embryonic morphology and ecology diversities, egg buoyancy has important variations within one species and among other ones. Nevertheless, it has hardly been explored if this buoyancy variability can be a strategy for deep-sea larvae to optimize their transport beyond their spawning areas. In the northwestern Mediterranean Sea, protozoea and mysis larvae of the commercial deep-sea shrimp Aristeus antennatus were recently found in upper layers, but to present, earlier stages like eggs and nauplii have not been collected. Using a Lagrangian transport model and larval characteristics, we evaluate the buoyancy and hydrodynamic effects on the transport of A. antennatus' larvae in the northwestern Mediterranean Sea. The transport models suggested that 75% of buoyant eggs released between 500 and 800 m depth (i.e., known spawning area), reached the upper water layers (0-75 m depth). Then, according to the modeled larval drifts, three spawning regions were defined in the studied area: 1) the northern part, along a continental margin crossed by large submarine canyons; 2) the central part, with two circular circulation structures (i.e., eddies); and 3) the southern part, with currents flowing through a channel. The number of larvae in the most upper layer (0-5 m depth) was higher if the larval transport model accounted for the ascent of eggs and nauplii (81%) instead of eggs reaching the surface before hatching (50%). The larvae reaching the most water upper layer (0-5 m depth) had higher rates of dispersal than the ones transported below the surface layer (deeper than 5 m depth). The results of larval dispersal simulations have implications for the understanding of A. antennatus larval ecology and for management decisions related to the shrimp fisheries in the northwestern Mediterranean Sea.


Assuntos
Crustáceos/fisiologia , Larva/fisiologia , Modelos Biológicos , Óvulo/fisiologia , Animais , Pesqueiros , Peixes/fisiologia , Hidrodinâmica , Mar Mediterrâneo , Alimentos Marinhos
7.
PLoS One ; 15(1): e0228184, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31995591

RESUMO

BACKGROUND: The existing diagnostic techniques for detecting schistosomiasis turkestanica, such as aetiological assays, identify infection by parasitic worms via the incubation of miracidia from faeces or observing eggs under microscopy. However, they are limited in the diagnosis of low-grade and prepatent infections, which lead to a high misdetection rates. Therefore, a new method for parasite diagnosis with increased sensitivity is urgently needed. METHODS: Goats in Nimu County (Tibet, China) infected with Schistosoma turkestanicum in an epidemic area were selected according positivity for the infection by faecal examination. Adult worms were collected, eggs were extracted by the sodium hydroxide (NaOH) erosion method, and soluble worm antigen preparation (SWAP) and soluble egg antigen (SEA) were isolated. The best coating concentration of the antigens and the best degree of dilution for serum were determined by square array experiments, and the optimal blocking solution and serum diluents were selected. The specificity, sensitivity and crossover of the ELISA method were determined using 48 samples of goat sera positive for S. turkestanicum, 100 samples of goat sera negative for S. turkestanicum, and 54 samples of buffalo sera positive for S. japonicum. Serological assays were established with samples from goats naturally grazed in a rural area of Nimu County, Tibet Province, by using the indirect ELISA method for the diagnosis of schistosomiasis, and faeces were collected for miracidia hatching. The sensitivity of the two detection methods was compared. RESULTS: Eggs of S. turkestanicum were distributed in the host duodenum and small intestine. Eggs in the host intestinal wall were extracted by the NaOH erosion method, which provided intact eggs with reduced impurities. The testing results obtained by isolating SEA were more stable than those obtained by using SWAP and less affected by the coating concentration and serum dilution. Additionally, the value of positive serum/negative (P/N) serum for SEA was much higher than that for SWAP. The optimal coating concentration of SEA was 0.5 µg/ml, and the optimal serum dilution was 1:100. The specificity and sensitivity of the indirect ELISA based on SEA (S. turkestanicum) were both 100%, and no cross-reactivity was found with schistosomiasis japonica. An epidemiological survey of goats in naturally infected areas showed that the prevalence rate of schistosomiasis turkestanica was 93%, and the infection rate increased with the ages of the goats. CONCLUSION: We aimed to develop a sensitive method to utilize in the mass field screening of livestock. As a diagnostic antigen, SEA (S. turkestanicum) was more suitable for serological testing than SWAP (S. turkestanicum). The indirect ELISA using SEA (S. turkestanicum) exhibited good sensitivity, specificity and no cross-reactivity with schistosomiasis japonica. The degree of infectivity and prevalence of S. turkestanicum infection in endemic areas are serious and should be a focus of concern among local departments.


Assuntos
Antígenos de Helmintos/imunologia , Ensaio de Imunoadsorção Enzimática/veterinária , Schistosoma , Esquistossomose/veterinária , Testes Sorológicos/veterinária , Animais , Reações Cruzadas/imunologia , Doenças das Cabras/diagnóstico , Doenças das Cabras/parasitologia , Cabras/parasitologia , Óvulo/imunologia , Schistosoma/imunologia , Schistosoma japonicum/imunologia , Esquistossomose/diagnóstico , Esquistossomose/imunologia , Sensibilidade e Especificidade , Tibet
8.
Nat Commun ; 11(1): 270, 2020 01 14.
Artigo em Inglês | MEDLINE | ID: mdl-31937751

RESUMO

Phase separation of substrates and effectors is proposed to enhance biological reaction rates and efficiency. Targeting protein for Xklp2 (TPX2) is an effector of branching microtubule nucleation in spindles and functions with the substrate tubulin by an unknown mechanism. Here we show that TPX2 phase separates into a co-condensate with tubulin, which mediates microtubule nucleation in vitro and in isolated cytosol. TPX2-tubulin co-condensation preferentially occurs on pre-existing microtubules, the site of branching microtubule nucleation, at the endogenous and physiologically relevant concentration of TPX2. Truncation and chimera versions of TPX2 suggest that TPX2-tubulin co-condensation enhances the efficiency of TPX2-mediated branching microtubule nucleation. Finally, the known inhibitor of TPX2, the importin-α/ß heterodimer, regulates TPX2 condensation in vitro and, consequently, branching microtubule nucleation activity in isolated cytosol. Our study demonstrates how regulated phase separation can simultaneously enhance reaction efficiency and spatially coordinate microtubule nucleation, which may facilitate rapid and accurate spindle formation.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Microtúbulos/metabolismo , Tubulina (Proteína)/metabolismo , Proteínas de Xenopus/metabolismo , Animais , Proteínas de Ciclo Celular/química , Citosol/metabolismo , Carioferinas/metabolismo , Meiose , Proteínas Associadas aos Microtúbulos/química , Centro Organizador dos Microtúbulos/metabolismo , Óvulo/citologia , Óvulo/metabolismo , Fuso Acromático/metabolismo , Proteínas de Xenopus/química , Xenopus laevis
9.
J Insect Sci ; 20(1)2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31925425

RESUMO

Diaphania caesalis (Walker) is an important boring insect mainly distributed in subtropical and tropical areas and attacked tropical woody grain crops, such as starchy plants of Artocarpus. Quantitative real-time polymerase chain reaction (qRT-PCR) is a powerful approach for investigating target genes expression profiles at the transcriptional level. However, the identification and selection of internal reference genes, which is often overlooked, is the most vital step before the analysis of target gene expression by qRT-PCR. So far, the reliable internal reference genes under a certain condition of D. caesalis have not been investigated. Therefore, this study evaluated the expression stability of eight candidate reference genes including ACT, ß-TUB, GAPDH, G6PDH, RPS3a, RPL13a, EF1α, and EIF4A in different developmental stages, tissues and sexes using geNorm, NormFinder and BestKeeper algorithms. To verify the stability of the recommended internal reference genes, the expression levels of DcaeOBP5 were analyzed under different treatment conditions. The results indicated that ACT, RPL13a, ß-TUB, RPS3a, and EF1α were identified as the most stable reference genes for further studies on target gene expression involving different developmental stages of D. caesalis. And ACT and EIF4A were recommended as stable reference genes for different tissues. Furthermore, ACT, EF1α, and RPS3a were ranked as the best reference genes in different sexes based on three algorithms. Our research represents the critical first step to normalize qRT-PCR data and ensure the accuracy of expression of target genes involved in phylogenetic and physiological mechanism at the transcriptional level in D. caesalia.


Assuntos
Expressão Gênica , Genes de Insetos , Mariposas/genética , Animais , Perfilação da Expressão Gênica , Larva/genética , Larva/crescimento & desenvolvimento , Mariposas/crescimento & desenvolvimento , Óvulo/crescimento & desenvolvimento , Pupa/genética , Pupa/crescimento & desenvolvimento , Reação em Cadeia da Polimerase em Tempo Real
10.
PLoS One ; 15(1): e0226600, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31914136

RESUMO

Since the size of newly hatched larval fish is directly related to egg size, small differences in initial egg size can be critical to survival and further development of offspring. Underlying processes causing size variation in fish offspring are still not entirely understood. In this study we investigated whether the spatial position of an individual egg within a clutch affects size variation in two benthic spawning coral reef fishes, the clownfishes Amphiprion ocellaris and A. frenatus. To evaluate the effects of within-clutch position on embryonic development, egg growth metrics and protein content were analysed on day 2, 5 and 8 after deposition (adp). Additionally the activities of the key metabolic enzymes citrate synthase (CS) and lactate dehydrogenase (LDH) were investigated to evaluate the physiological status of the embryos. Central eggs of A. frenatus were significantly longer and heavier than peripheral eggs only on day 2 and 5 adp (2.07 mg, 2.59 mm vs. 1.84 mg, 2.49 mm). No significant differences were observed in A. ocellaris between eggs originating from a central or peripheral (5 mm from edge) position (1.33 mg, 2.26 mm vs. 1.15 mg, 2,18 mm). Diameter of the eyes did not differ between the two fish species nor between different positions, for any age group. The protein content of eggs (7.5% of wet weight) was independent of age, position and species. Enzymatic activity increased from 2 adp until peak activity was observed for both enzymes on day 8 adp, independent from position. The range of CS- and LDH-activity was 0.3-13.0 and 0.2-71.7 U g-1 wet weight, respectively. Significant differences in enzymatic activity were observed between age groups in both species, which in connection with significantly larger eggs of A. frenatus at day 2 and 5 adp could hint at a better O2 supply of central eggs. Potential implications for captive breeding are given.


Assuntos
Proteínas do Ovo/metabolismo , Embrião não Mamífero/citologia , Embrião não Mamífero/enzimologia , Desenvolvimento Embrionário , Óvulo/citologia , Perciformes/embriologia , Perciformes/metabolismo , Animais , Óvulo/enzimologia , Processamento Espacial
11.
Chemosphere ; 243: 125424, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31995877

RESUMO

Trace metal and metalloid levels were measured in eggs of the NW Atlantic leatherback turtle (Dermochelys coriacea) from nesting grounds in the Bocas del Toro province, Panama, to infer exposure and associated risks to local communities. Samples were analyzed for a set of 26 essential and non-essential elements using inductively coupled plasma techniques. Median concentrations of Fe, Zn, As, Se and Sr in D. coriacea eggs were higher than previously reported for this species, which likely reflects differential contamination levels of specimens during foraging. The evaluation of non-carcinogenic human health risks from ingesting leatherback eggs has revealed potential deleterious effects due to high concentrations of As, Se and Sr for all examined age and gender groups, while Hg and Zn levels were above international standards for children. Hazard index (HI) values exceeded unity in all cases indicating serious health impacts related to possible additive effects of multiple metals co-occurring in the eggs. Our findings suggest that exposure to high (inorganic) As and Cr(VI) levels is associated with an increased carcinogenic risk, significantly exceeding the acceptable lifetime risk of 10-6 for both adults and children. Despite some limitations, such as unclear As and Cr speciation, our results demonstrated that the ingestion of D. coriacea eggs poses considerable health risks to local communities, and their consumption should not exceed 3.4 × 10-4 g (5.0 × 10-6 eggs) kg BW d-1. Resource managers and conservationists should focus their attention to human health effects as an alternative tool to address egg poaching and consumption.


Assuntos
Contaminação de Alimentos/análise , Metais Pesados/análise , Óvulo/química , Oligoelementos/análise , Tartarugas/metabolismo , Animais , Região do Caribe , Feminino , Panamá
12.
Bull Entomol Res ; 110(1): 22-33, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31190648

RESUMO

Plant-sucking stinkbugs are especially associated with mutualistic gut bacterial symbionts. Here, we explored the symbiotic relationship of a pistachio stinkbug, Acrosternum heegeri Fieber by histological, fluorescence in situ hybridization (FISH), real-time PCR and molecular phylogenetic techniques. Furthermore, the effects of the symbiont on the resting/wandering behaviors of the newborn nymphs, pre-adult survival rates, and stage compositions were investigated. Transmission electron microscopy and real-time PCR analyses showed that a rod-shaped gammaproteobacterium was persistently located within the posterior midgut crypts. Molecular phylogenetic and FISH techniques strongly suggested that this symbiont should be placed in the genus Pantoea of the Enterobacteriales. Scanning electron microscopy confirmed the presence of the bacterial cells on the egg surface which the surface sterilization of the eggs resulted in the successful removal of the symbiont from the eggs. Symbiotic and aposymbiotic A. heegeri showed no significant differences in the wandering behaviors of the first nymphal stages, while the symbiont-free insects suffered retarded growth and lower survivability. Together, the results highlight the habitat and acquisition features of Pantoea symbiont and its contribution in A. heegeri biology that might help us for better pest management in the future.


Assuntos
Gammaproteobacteria/isolamento & purificação , Heterópteros/microbiologia , Animais , Feminino , Trato Gastrointestinal/microbiologia , Trato Gastrointestinal/ultraestrutura , Heterópteros/ultraestrutura , Ovário/microbiologia , Óvulo/microbiologia , Simbiose
13.
Bull Entomol Res ; 110(1): 161-168, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31337456

RESUMO

The tettigoniid Barbitistes vicetinus Galvagni & Fontana was described in 1993 as an endemic and rare bush-cricket of north-east Italy. Since 2008, this species has become a pest, causing repeated outbreaks with severe defoliations in broadleaf forests and neighbouring crops. Few data are currently available on ecology and life-cycle of this species, in particular about how temperature regulates egg-diapause and hatching phenology. The present work reports a field study regarding hatching phenology of B. vicetinus, surveyed with 84 emergence traps over four consecutive years (2013-2016). Moreover, the effect of temperature on the hatching was tested in the laboratory, exposing eggs to different temperatures. Field observations showed that hatching occurred between the end of March and beginning of April. In warmer years, hatching started early in the spring and lasted longer, while in colder years, hatching started later and was concentrated in a few days. Moreover, a significant effect of both elevation and exposure on the hatching start was observed. Results obtained from laboratory suggested the ability of the species to develop in the post-final diapause in a wide range of thermal conditions. After the diapause (terminated by a prolonged common exposure to low temperature) B. vicetinus was able to hatch from 6 to 23°C although, due to prolonged post-diapause development, hatching took place progressively later at colder temperatures. To manage B. vicetinus outbreaks, forecasting the seasonal phenology of egg hatching and its duration is important for an effective pest control.


Assuntos
Diapausa de Inseto , Gryllidae/crescimento & desenvolvimento , Óvulo/crescimento & desenvolvimento , Animais , Feminino , Masculino , Temperatura
14.
Bull Entomol Res ; 110(1): 136-143, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31203829

RESUMO

The oriental armyworm, Mythimna separata is an important crop pest in eastern Asia. Nocturnal insects, including nocturnal moths, have phototactic behavior to an artificial light source. Phototactic behavior in insects is species-specific in response to different wavelengths of light sources. Our previous study showed that green (520 nm) light emitting diode (LED) light resulted in a significantly higher phototactic behavior in M. separata moths compared to the other wavelength LED lights. The goal of the present study is to investigate the influence of green light illumination on biological characteristics of different developmental stages in M. separata. Our results revealed that when different developmental stages of M. separata were exposed to the green light illumination in a dark period, several biological characteristics in all developmental stages except for egg stage were positively changed, but those of F1 generation M. separata which are next generation of the adults exposed to the green light did not significantly change compared with the control level. These findings suggest that green light illumination at night (or dark period) has a positive effect on the development and longevity of M. separata.


Assuntos
Mariposas/efeitos da radiação , Animais , Feminino , Larva/efeitos da radiação , Luz , Longevidade/efeitos da radiação , Masculino , Mariposas/crescimento & desenvolvimento , Óvulo/efeitos da radiação , Pupa/efeitos da radiação , Reprodução/efeitos da radiação
15.
Forensic Sci Int ; 306: 110075, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31794867

RESUMO

The list of factors influencing the development of forensically important insects and the related effects on minimum post mortem (PMImin) estimations is long and well established by various authors in forensic entomology over the last decades. Despite the fact that several authors mention precocious egg development, i.e. first instar larva in the genital tract of some species of Calliphoridae, as a potential error source for PMImin estimations just two studies were performed to examine the occurrence of precocious eggs both in laboratory and field populations of blow flies. In the present study the occurrence of gravid females with precocious eggs in a wild population of Calliphora vicina in Frankfurt am Main was surveyed over 152 days and their seasonal distribution was analyzed as well as the influence of abiotic variables on their abundance. During the sampling occasions, 5.216 females were sampled of which 44 % were gravid. 54 % of all gravid females had a precocious egg/first instar larva in their genital tract. This number varied depending on the season and showed the highest amount in spring with almost 64 % of all gravid females. Hence, precocious eggs in wild populations of blow flies can occur much more frequently than mentioned in forensic literature. Consequences for the evaluation of entomological evidence in forensic casework should not be overrated since focusing alone on the largest larva in a sample is not recommended as the sole reference in an entomological PMImin estimation. The entomological report has to justify its findings, discuss different options and finally state what is considered to be the most likely scenario based on the complete evidence (e.g. including all species and relevant age cohorts as well as succession data) and the case specific history.


Assuntos
Dípteros/fisiologia , Larva/fisiologia , Animais , Dípteros/crescimento & desenvolvimento , Feminino , Larva/crescimento & desenvolvimento , Oviposição/fisiologia , Ovoviviparidade/fisiologia , Óvulo/crescimento & desenvolvimento , Óvulo/fisiologia , Estações do Ano
16.
Insect Sci ; 27(1): 159-169, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29851277

RESUMO

Agasicles hygrophila has been introduced worldwide as a control agent for the invasive weed Alternanthera philoxeroides. However, global warming has potential impact on its controlling efficacy. The aim of this research was to explore the primary factors responsible for the greatly reduced A. hygrophila population in hot summers. To imitate the temperature conditions in summers, different developmental stages of A. hygrophila were treated with high temperatures from 32.5 °C to 45 °C for 1-5 h. Based on the survival rate, the heat tolerance of each developmental stage was ranked from lowest to highest as follows: egg, 1st, 2nd, 3rd instar larva, adult and pupa. Eggs showed the lowest heat tolerance with 37.5 °C as the critical temperature affecting larval hatching. Heat treatment of the A. hygrophila eggs at 37.5 °C for 1 h decreased the hatch rate to 24%. Our results indicated that when compared with the control at 25 °C, 1 h treatment at 37.5 °C prolonged the duration of the egg stage, shortened the duration of oviposition and total longevity, and changed the reproductive pattern of A. hygrophila. The net reproductive rate, intrinsic rate and finite rate were all significantly reduced. The results suggest that low heat tolerance of the eggs was the major factor responsible for the reduction of A. hygrophila populations, and the key temperature was 37.5 °C. Therefore, appropriate measures should be taken to protect eggs in order to maintain the efficacy of A. hygrophila in the biological control of A. philoxeroides in hot summers.


Assuntos
Besouros/fisiologia , Temperatura Alta/efeitos adversos , Termotolerância , Animais , Besouros/crescimento & desenvolvimento , Feminino , Larva/crescimento & desenvolvimento , Larva/fisiologia , Masculino , Óvulo/fisiologia , Pupa/crescimento & desenvolvimento , Pupa/fisiologia , Estações do Ano
17.
Theriogenology ; 141: 113-119, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31536860

RESUMO

The objective of this research was to develop a system for piglet production by transvaginal ultrasound-guided ovum pick-up (OPU), in vitro production (IVP) of embryos and embryo transfer. First, to establish a culture system for a small number of oocytes or embryos, we evaluated the effect of different incubation volumes and culture densities on fertilizing ability and developmental competence in vitro. Porcine oocytes derived from slaughterhouse ovaries were matured, fertilized and then cultured in vitro in groups as follows: 50 oocytes in 500 µL medium for IVM, 20 oocytes in 100 µL medium for IVF and 20 embryos in 40 µL medium for IVC (Group I); 20 in 100 µL for IVM, 20 in 100 µL for IVF and 20 in 40 µL for IVC (Group II); and 10 in 100 µL for IVM, 10 in 100 µL for IVF and 10 in 40 µL for IVC (Group III). Percentages of sperm penetration, cleavage and blastocyst formation did not differ among the groups. Second, to increase the collection efficiency of porcine oocytes by transvaginal ultrasound-guided OPU, the effects of aspiration pressure on follicular oocyte collection were assessed. Oocytes were aspirated from ovaries of live sows using 80 or 100 mmHg. The recovered oocytes were divided into four categories according to the surrounding cumulus cells and quality of oocytes. The number of oocytes recovered using 100 mmHg pressure was significantly higher than with 80 mmHg pressure. However, there were no significant differences in the population of oocytes grouped by the morphological criteria, number of blastocysts per session and the total cell number in blastocysts between the two vacuum pressures. Finally, 81 oocytes obtained by OPU from five donor sows were subjected to IVP and 47 transferable embryos (9.4 ±â€¯4.0 [mean ±â€¯SD] morulae/blastocysts per session) were obtained at 5 days after IVF. When they were transferred into five recipient gilts (5-16 embryos per recipient), three of five recipients became pregnant and farrowed a total of 12 live piglets. The present results demonstrate that porcine blastocysts can be produced by OPU-IVP and develop to full term after embryo transfer.


Assuntos
Blastocisto/fisiologia , Técnicas de Cultura Embrionária/veterinária , Fertilização In Vitro/veterinária , Óvulo/fisiologia , Suínos , Ultrassonografia/veterinária , Animais , Doadores de Tecidos , Coleta de Tecidos e Órgãos
18.
Theriogenology ; 141: 146-152, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31541784

RESUMO

Differences in reproductive physiology between cattle breeds may help to explain distinct responses to assisted reproductive techniques and to define breed-specific protocols with improved efficiency. Germinal vesicle (GV) stage oocytes are characterized by increasing levels of chromatin compaction enclosed within the nucleus (graded from GV0 to GV3), associated with different developmental competence. The first objective of this study was to characterize chromatin configuration of GV stage oocytes recovered by OPU at random days of the estrous cycle from Nelore (Bos indicus) and Holstein (Bos taurus) cows. In Nelore 90% of the oocytes presented advanced stages of chromatin compaction associated with higher developmental competence (GV2 and GV3), while in Holstein, only 65% of the oocytes were at these stages. Then, aiming to obtain a more homogeneous population of oocytes in Holstein, we tested two synchronization protocols combining aspiration of all visible follicles at a random day (day 0), two IM injections of FSH 12 h apart on day 2, and OPU on day 4 (OPU/D4) or 5 (OPU/D5). The protocol OPU/D4 provided around 45% of the oocytes with low chromatin compaction (GV1), while the protocol OPU/D5 provided 70% of the oocytes at GV2 and 20% at GV3. Finally, we assessed the effects of a culture system known to prevent meiotic resumption on chromatin configuration of the GV2 enriched oocyte population obtained with the protocol OPU/D5. After 9 h of culture most oocytes transited from GV2 to GV3, with 90% of the oocytes at GV3 stage. This study demonstrates differences between Nelore and Holstein cows regarding patterns of chromatin configuration that may account for their different performance in IVM/IVF. In addition, it provides novel references for the design of protocols aiming to regulate oocyte quality before IVM for the optimization of IVF outcomes.


Assuntos
Bovinos/genética , Bovinos/fisiologia , Montagem e Desmontagem da Cromatina/fisiologia , Oócitos/fisiologia , Animais , Técnicas de Cultura Embrionária/veterinária , Ciclo Estral , Hormônio Foliculoestimulante , Técnicas de Maturação in Vitro de Oócitos/veterinária , Meiose , Óvulo , Doadores de Tecidos , Coleta de Tecidos e Órgãos
19.
Ann Agric Environ Med ; 26(4): 606-616, 2019 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-31885235

RESUMO

INTRODUCTION AND OBJECTIVE: The tendency towards postponement of maternity implies a greater exposure of female germ cells to damaging environmental effects, including ionizing radiation (IR). Progress in paediatric oncology, based on the use of radiotherapy, also implies the occurrence of gonadal dysfunctions and subsequent female fertility disorders. Therefore, it seems justifiable to systematize the state of knowledge concerning the effect of IR on the female reproductive system. BRIEF DESCRIPTION OF THE STATE OF KNOWLEDGE: A considerable part of studies concerning the effect of IR on female germ cells have been conducted on animals. Their extrapolation to humans is hindered because in animal studies high acute exposures are applied, which do not reflect human environmental exposures characterized by chronic low dose exposure. Studies on animals provide a heterogenous image, which hinders the formulation of unequivocal conclusions and indicates that radiosensitivity depends, i.a. on IR dose, stage of development of oocytes, the applied marker of the effects of IR, or on the species. LD50 of human oocytes is estimated to be below 2 Gy. The effect of IR depends, i.a. on the dose fractionation and the age (older women are more radiosensitive). In females, the effective sterilizing dose is: at birth 20.3 Gy, at 10 years 18.4 Gy, at 20 years 16.5 Gy, whereas at 30 years 14.3 Gy, which is associated with the available pool of ovarian follicles. CONCLUSIONS: Within the range of low doses received as a result of environmental exposure to IR, there is no evidence for the occurrence of either adverse pregnancy outcomes, nor fertility disorders in females. These effects may be related to the cancer radiotherapy, or exposure to high IR doses during nuclear accidents.


Assuntos
Exposição à Radiação/efeitos adversos , Lesões por Radiação/fisiopatologia , Reprodução/efeitos da radiação , Animais , Feminino , Humanos , Óvulo/efeitos da radiação , Lesões por Radiação/etiologia , Radiação Ionizante
20.
PLoS One ; 14(12): e0226061, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31856229

RESUMO

Collective migration plays critical roles in animal development, physiological events, and cancer metastasis. However, the molecular mechanisms of collective cell migration are not well understood. Drosophila border cells represent an excellent in vivo genetic model to study collective cell migration and identify novel regulatory genes for cell migration. Using the Mosaic Analysis with a Repressible Cell Marker (MARCM) system, we screened 240 P-element insertion lines to identify essential genes for border cell migration. Two genes were uncovered, including dlg5 (discs large 5) and CG31689. Further analysis showed that Dlg5 regulates the apical-basal polarity and cluster integrity in border cell clusters. Dlg5 is enriched in lateral surfaces between border cells and central polar cells but also shows punctate localization between border cells. We found that the distribution of Dlg5 in border cell clusters is regulated by Armadillo. Structure-function analysis revealed that the N-terminal Coiled-coil domain and the C-terminal PDZ3-PDZ4-SH3-GUK domains but not the PDZ1-PDZ2 domains of Dlg5 are required for BC migration. The Coiled-coil domain and the PDZ4-SH3-GUK domains are critical for Dlg5's cell surface localization in border cell clusters.


Assuntos
Proteínas de Drosophila/metabolismo , Drosophila/metabolismo , Guanilato Quinases/metabolismo , Oogênese , Animais , Proteínas do Domínio Armadillo/metabolismo , Membrana Celular/metabolismo , Movimento Celular , Polaridade Celular , Drosophila/crescimento & desenvolvimento , Proteínas de Drosophila/antagonistas & inibidores , Proteínas de Drosophila/química , Genes Reporter , Guanilato Quinases/antagonistas & inibidores , Guanilato Quinases/química , Óvulo/crescimento & desenvolvimento , Óvulo/metabolismo , Domínios Proteicos , Proteína Quinase C/metabolismo , Interferência de RNA , Proteínas de Ligação a RNA/metabolismo , Fatores de Transcrição/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA