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1.
Ann Parasitol ; 67(2): 265-273, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34597499

RESUMEN

Toxocara spp. (T. canis and T. cati in particular) are the major etiological nematodes that have contributed to visceral larval migrans (VLM). So to show the ability of T. cati to produce such migration in the rats as experimental model and detection through histopathological observations to detect larval migratory patterns. Adult females T. cati were collected from naturally infected feral cats. Eight rats, Rattus norvegicus had acted as a model for experimental infection, each receiving an infectious dose of about 1000 infective T. cati eggs, while 2 rats served as non-infected control group. Two infected rats were sacrificed and examined at 7, 14, 21, and 28 day post infection (dpi) and tissue samples were taken for digestioning order to recover migrated larvae and for histopathological examination. In vitro embryonation of T. cati eggs was successfully carried out, although the percentage of embryonation was 10%, prepared inoculums were also infective to rats. Larvae recovered from the lungs at 7 and 14 dpi and were also present at 21, and 28 dpi. The larvae of T. cati were present in the intestines at 14, and 21 dpi. There were no larvae or less than one larva per gram found in other studied tissues. Histopathological changes in different organs were observed. Generally speaking, a multi-tissue response can be defined as the histopathological response of T. cati larval migration. The migratory larvae of T. cati can cause severe histopathological alterations in various tissues and organs of infected animals, within the current study shows that the lungs are a favorable site of migration for these larvae. T. cati is a zoonotic parasite that is underestimated.


Asunto(s)
Toxocara canis , Toxocara , Animales , Gatos , Grupos Control , Femenino , Larva , Ratas
2.
Ann Parasitol ; 67(2): 305-312, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34598402

RESUMEN

This study aimed to investigate the presence of nematodes Spirocamallanus krameri and Contracaecum sp. in Hoplerythrinus unitaeniatus caught in a lake in the state of Pará, in northern Brazil, eastern Amazon region (Brazil). From 92 hosts, 83.7% were infected, and a total of 401 parasites were covered. There was a high prevalence of S. krameri, while the predominance was of Contracaecum sp. larvae. Both parasite species presented aggregated dispersion, and abundance of these parasites presented positive correlation with weight and length of the hosts. Morphological and morphometric data of third-stage larvae of Contracaecum sp. are described.


Asunto(s)
Characiformes , Enfermedades de los Peces , Nematodos , Parásitos , Animales , Brasil/epidemiología , Larva
3.
J Agric Food Chem ; 69(40): 11816-11824, 2021 Oct 13.
Artículo en Inglés | MEDLINE | ID: mdl-34596393

RESUMEN

The continued success of pest control using insecticidal crystal (Cry) proteins from Bacillus thuringiensis (Bt) in transgenic plants was threatened by the evolution of resistance. Previous studies suggested that polycalin from Plutella xylostella could bind to Cry1Ac toxin as a potential receptor. In this study, a fragment of P. xylostella polycalin (Pxpolycalinf, G2209-A2942) containing a carboxyl-terminal GPI-anchored signal peptide was cloned and expressed. Purified Pxpolycalinf retained the binding ability to Cry1Ac and synergized Cry1Ac toxicity to the third larvae of P. xylostella in bioassays. Moreover, the polyclonal antibody of Pxpolycalinf decreased the Cry1Ac activity after being fed together with normal food. Further, the ELISA results showed the concentration-dependent binding of Pxpolycalinf to P. xylostella brush border membrane vesicles (BBMV). Spodoptera frugiperda 9 (Sf9) cells expressing Pxpolycalinf were not susceptive to Cry1Ac, whereas Pxpolycalinf increased Cry1Ac cytotoxicity to Sf9 cells expressing P. xylostella ATP-dependent binding cassette transporter C2 (PxABCC2). Immunolocalization presented the binding of Pxpolycalinf to the Sf9 cell membrane, and ELISA showed the concentration-dependent binding of Pxpolycalinf to Sf9 cell extraction. These results here provide the first evidence that a fragment of P. xylostella polycalin, a potential receptor of Cry1Ac, synergizes Cry1Ac toxicity to P. xylostella larvae and Sf9 cells expressing PxABCC2.


Asunto(s)
Bacillus thuringiensis , Mariposas Nocturnas , Animales , Bacillus thuringiensis/genética , Toxinas de Bacillus thuringiensis , Proteínas Bacterianas/genética , Endotoxinas/genética , Proteínas Hemolisinas/genética , Proteínas de Insectos/genética , Resistencia a los Insecticidas , Larva/genética , Mariposas Nocturnas/genética
4.
Braz J Biol ; 83: e245922, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34468513

RESUMEN

Crustose coralline algae (Corallinophycideae) are red algae that produced calcium carbonate and are well recognized as foundation species in the epipelagic zone of the marine ecosystem. These algae induced settlement juvenile of coral by released chemical cues from bacterial communities on the surface of their colonies. Their extracellular calcium carbonate also can stabilize reef structure that influencing many invertebrate attaches and growth in the seabed. Crustose coralline algae (CCA) have obtained attention because of their distribution and health compromise to increasing seawater temperature, ocean acidification, and pollutant. As a cryptic species in the ecosystem, the presence of CCA recruit sometimes doesn't have attention, especially on their capability to occupy the empty space. This study aimed to document coverage and number of CCA recruit in two different recruitment tile's material. The highest CCA percentage of the cover was showed inside surface than others surface in all stations. Light intensity and low sedimentation were suggested as a key factor of success of high coverage. Overall, station higher CCA recruits have shown from Tiga Warna. Low sedimentation and protection from aerial exposure became the main reason for it. No significant difference number of CCA recruits between marble and sandstone in this study. Successful CCA recruitment in this study can give a wide picture that natural recruitment of coral and other reef biodiversity in Southern Malang might be will succeed because of the abundance of coralline algae that support their life history stage.


Asunto(s)
Antozoos , Animales , Arrecifes de Coral , Ecosistema , Concentración de Iones de Hidrógeno , Indonesia , Larva , Agua de Mar
5.
J Agric Food Chem ; 69(34): 9743-9753, 2021 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-34465092

RESUMEN

Indirect defense is an important strategy employed by sessile plants to defend against herbivorous insects by recruiting the natural enemies of herbivores mediated by herbivore-induced plant volatiles (HIPVs). We aimed to determine whether indirect defense occurs in Compositae with Chrysanthemum morifolium as the model and elucidate the mechanisms underlying the biosynthesis of HIPVs. Using two-choice olfactometer bioassays, we showed that C. morifolium plants following infestation by larvae of the tobacco cutworm (Spodoptera litura, TCW) were significantly more attractive to two natural enemies of TCW larvae than control plants, indicating that indirect defense is an active defense strategy of C. morifolium. The chemical cue responsible for indirect defense in C. morifolium was identified as a complex blend of volatiles predominated by sesquiterpenes and monoterpenes. A total of 11 candidate terpene synthase (TPS) genes were identified by comparing the transcriptomes of healthy and TCW-infested plants. Gene expression analysis confirmed that up-regulated CmjTPS genes are consistent with the elevated emission of terpenes after herbivory treatment. Our study showed that the herbivore-induced emission of JA-dependent volatile terpenes attracted both predatory and parasitic enemies of herbivores. Generally, our findings indicate that indirect defense might be an important defense mechanism against insects in C. morifolium.


Asunto(s)
Chrysanthemum , Herbivoria , Animales , Chrysanthemum/genética , Larva , Spodoptera/genética , Terpenos
6.
Rev Bras Parasitol Vet ; 30(3): e009221, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34495124

RESUMEN

This study aimed to chemically characterize the essential oils (EOs) of Cinnamomum zeylanicum (cinnamon) and Eremanthus erythropappus (candeia) and evaluate their acaricidal activity, together with that of their major compounds and cinnamyl acetate derivative, against Rhipicephalus microplus. Essential oil compounds were identified through gas chromatography. The larval packet test (LPT) at concentrations ranging from 0.31 to 10.0 mg/mL and the adult immersion test (AIT) at concentrations between 2.5 and 60.0 mg/mL were performed. (E)-cinnamaldehyde and α-bisabolol were the major compounds in cinnamon (86.93%) and candeia (78.41%) EOs, respectively. In the LPT, the EOs of cinnamon and candeia and the compounds (E)-cinnamaldehyde, α-bisabolol and cinnamyl acetate resulted in 100% mortality at concentrations of 2.5, 2.5, 5.0, 10.0 and 10.0 mg/mL respectively. In the AIT, percentage control values > 95% were observed for cinnamon and candeia EOs, (E)-cinnamaldehyde and α-bisabolol at the concentrations of 5.0, 60.0, 20.0, and 20.0 mg/mL, respectively, whereas cinnamyl acetate showed low activity. We conclude that EOs and their compounds showed high acaricidal activity, whereas the acetylated derivative of (E)-cinnamaldehyde presented less acaricidal activity on R. microplus engorged females.


Asunto(s)
Acaricidas , Aceites Volátiles , Rhipicephalus , Acaricidas/farmacología , Animales , Cinamatos , Cinnamomum zeylanicum , Larva , Aceites Volátiles/farmacología
7.
Braz J Biol ; 83: e246230, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34495158

RESUMEN

Dengue fever vectored by the mosquito Aedes aegypti is one of the most rapidly spreading insect-borne diseases. Current reliance of dengue vector control is mostly on chemical insecticides. Growing insecticide resistance in the primary mosquito vector, Aedes aegypti, limits the effectiveness of vector control through chemical insecticides. These chemical insecticides also have negative environmental impacts on animals, plants and human health. Myco-biocontrol agents are naturally occurring organisms and are found to be less damaging to the environment as compared to chemical insecticides. In the present study, entomopathogenic potential of local strains of fungi isolated from soil was assessed for the control of dengue vector. Local fungal isolates presents better alternative to introducing a foreign biocontrol strain, as they may be better adapted to environmental conditions of the area to survive and may have more entomopathogenic efficacy against target organism. Larvicidal efficacy of Fusarium equiseti and Fusarium proliferatum was evaluated against Aedes aegypti. Local strains of F. equiseti (MK371718) and F. proliferatum (MK371715) were isolated from the soil of Changa Manga Forest, Pakistan by using insect bait method. Larvicidal activity of two Fusarium spp. was tested against forth instar larvae of A. aegypti in the laboratory, using concentrations 105, 106, 107 and 108 conidia /ml. LC50 values for F. equiseti after 24h, 48h, 72h and 96h of exposure were recorded as 3.8x 108, 2.9x107, 2.0x107, and 7.1x106 conidia /ml respectively while LC50 values for F. proliferatum were recorded as 1.21x108, 9.6x107, 4.2x107, 2.6x107 conidia /ml respectively after 24h, 48h, 72h and 96h of exposure. The results indicate that among two fungal strains F. equiseti was found to be more effective in terms of its larvicidal activity than F. proliferatum against larvae of A. aegypti.


Asunto(s)
Aedes , Fusarium , Insecticidas , Animales , Bosques , Humanos , Insecticidas/farmacología , Larva , Mosquitos Vectores , Pakistán , Extractos Vegetales , Suelo
8.
Braz J Biol ; 83: e246436, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34495159

RESUMEN

Application of different fertilizers to check the efficiency of expression of Bt (Bacillus thuringiensis) gene in one of the leading commercialized crops (cotton) against Lepidopteran species is of great concern. The expression of Cry protein level can be controlled by the improvement of nutrients levels. Therefore, the myth of response of Cry toxin to different combinations of NP fertilizers was explored in three Bt cotton cultivars. Combinations include three levels of nitrogen and three levels of phosphorus fertilizers. Immunostrips and Cry gene(s) specific primer based PCR (Polymerase Chain Reaction) analysis were used for the presence of Bt gene that unveiled the presence of Cry1Ac gene only. Further, the ELISA (enzyme-linked immunosorbent assay) kit was used to quantify the expression of Cry1Ac protein. Under various NP fertilizers rates, the level of toxin protein exhibited highly significant differences. The highest toxin level mean was found to be 2.3740 and 2.1732 µg/g under the treatment of N150P75 kg ha-1 combination while the lowest toxin level mean was found to be 0.9158 and 0.7641 µg/g at the N50P25 kg ha-1 level at 80 and 120 DAS (Days After Sowing), respectively. It was concluded from the research that the usage of NP fertilizers has a positive relation with the expression of Cry1Ac toxin in Bt cotton. We recommend using the N150P50 kg ha-1 level as the most economical and practicable fertilizer instead of the standard dose N100P50 kg ha-1 to get the desired level of Cry1Ac level for long lasting plant resistance (<1.5). The revised dose of fertilizer may help farmers to avoid the cross-resistance development in contradiction of insect pests.


Asunto(s)
Proteínas Hemolisinas , Mariposas Nocturnas , Animales , Toxinas de Bacillus thuringiensis , Proteínas Bacterianas/genética , Endotoxinas/genética , Fertilizantes , Proteínas Hemolisinas/genética , Resistencia a los Insecticidas , Larva , Nitrógeno , Fósforo , Plantas Modificadas Genéticamente/genética
9.
Environ Monit Assess ; 193(10): 636, 2021 Sep 08.
Artículo en Inglés | MEDLINE | ID: mdl-34498140

RESUMEN

Some wetlands in the northern Great Plains support hundreds to thousands of late-stage tadpoles providing important sources of recruitment to the Wood Frog (Lithobates sylvaticus) population while many other wetlands produce none. Relationships between water quality and late-stage tadpole abundance were determined to identify the water quality parameters associated with tadpole abundance. Water samples were collected, and late-stage tadpole abundances were assessed once each year in late June for 12 years in 26 wetlands. Catch or abundance was the number of tadpoles captured in 30 min with a dip-net. The catch of tadpoles was variable both among wetlands and over the long-term for individual wetlands, and ranged from 0 to several hundred individuals. Wood Frog tadpoles were especially sensitive to sodium and chloride concentrations. At Cl concentrations less than 5 mg/L, occupancy for late-stage tadpoles was 84%, and declined by about 8% for each 5 mg/L increase in Cl to 40.1 mg/L Cl, the maximum concentration associated with the detection of tadpoles. Optimal water quality for late-stage Wood Frog tadpoles included low concentrations of Na [Formula: see text] = 8.1 mg/L), and Cl [Formula: see text] = 4.2 mg/L) relative to total dissolved solids and other ions, and high concentrations of phosphorus. In a landscape where ion concentrations in wetlands can range over 3 orders of magnitude, water quality analyses suggest that abundant Wood Frog tadpole populations occur in wetlands dominated by snow-melt runoff with its characteristic low ion concentrations. The present study highlights the importance to amphibian conservation of the water quality environment of tadpole habitat.


Asunto(s)
Monitoreo del Ambiente , Calidad del Agua , Animales , Humanos , Larva , Ranidae , Humedales
10.
Artículo en Inglés | MEDLINE | ID: mdl-34494946

RESUMEN

Six yeast isolates were obtained from rotting wood samples in Brazil and frass of a cerambycid beetle larva in French Guiana. Sequence analysis of the ITS-5.8S region and the D1/D2 domains of the large subunit rRNA gene showed that the isolates represent a novel species of Cyberlindnera. This novel species is related to Cyberlindnera japonica, Cyberlindnera xylosilytica, Candida easanensis and Candida maesa. It is heterothallic and produces asci with two or four hat-shaped ascospores. The name Cyberlindnera dasilvae sp. nov. is proposed to accommodate the novel species. The holotype of Cy. dasilvae is CBS 16129T and the designated paratype is CBS 16584. The MycoBank number is 838252. All isolates of Cy. dasilvae were able to convert xylose into xylitol with maximum xylitol production within 60 and 72 h. The isolates produced xylitol with values ranging from 12.61 to 31.79 g l-1 in yeast extract-peptone-xylose medium with 5% xylose. When the isolates were tested in sugarcane bagasse hydrolysate containing around 35-38 g l-1d-xylose, isolate UFMG-CM-Y519 showed maximum xylitol production.


Asunto(s)
Escarabajos/microbiología , Filogenia , Saccharomycetales/clasificación , Madera , Xilitol , Animales , ADN de Hongos/genética , ADN Espaciador Ribosómico , Heces/microbiología , Larva/microbiología , Técnicas de Tipificación Micológica , Saccharomycetales/aislamiento & purificación , Análisis de Secuencia de ADN , Madera/microbiología , Xilitol/metabolismo
11.
JNMA J Nepal Med Assoc ; 59(239): 709-711, 2021 Jul 30.
Artículo en Inglés | MEDLINE | ID: mdl-34508503

RESUMEN

Myiasis is a skin infection caused by developing larvae (maggots) of various Diptera fly species. The two most frequent flies that cause human infestations around the world are Dermatobia hominis (human botfly) and Cordylobia anthropophaga (tumbu fly). Maggots have been found to infest the nose, ear, orbit, tracheostomy wound, face, gums, and serous cavities, among other places. Maggots at the colostomy site are an uncommon occurrence. We report a case of maggots infestation surrounding the colostomy site. We came across a rather rare finding in a patient with advanced inoperable rectum cancer who initially complained of persistent nonspecific pain, discomfort, and foul-smelling discharge from the colostomy site. The issue at hand was identified to be maggots, and their removal alleviated the patient's symptoms. We underline the importance of regularly monitoring stoma sites to avoid maggot infestation, especially in tropical regions.


Asunto(s)
Dípteros , Miasis , Animales , Calliphoridae , Colostomía , Humanos , Larva , Miasis/diagnóstico , Miasis/etiología , Miasis/terapia
12.
BMC Genomics ; 22(1): 639, 2021 Sep 04.
Artículo en Inglés | MEDLINE | ID: mdl-34479486

RESUMEN

BACKGROUND: Resistance of pest insect species to insecticides, including B. thuringiensis (Bt) pesticidal proteins expressed by transgenic plants, is a threat to global food security. Despite the western corn rootworm, Diabrotica virgifera virgifera, being a major pest of maize and having populations showing increasing levels of resistance to hybrids expressing Bt pesticidal proteins, the cell mechanisms leading to mortality are not fully understood. RESULTS: Twenty unique RNA-seq libraries from the Bt susceptible D. v. virgifera inbred line Ped12, representing all growth stages and a range of different adult and larval exposures, were assembled into a reference transcriptome. Ten-day exposures of Ped12 larvae to transgenic Bt Cry3Bb1 and Gpp34/Tpp35Ab1 maize roots showed significant differential expression of 1055 and 1374 transcripts, respectively, compared to cohorts on non-Bt maize. Among these, 696 were differentially expressed in both Cry3Bb1 and Gpp34/Tpp35Ab1 maize exposures. Differentially-expressed transcripts encoded protein domains putatively involved in detoxification, metabolism, binding, and transport, were, in part, shared among transcripts that changed significantly following exposures to the entomopathogens Heterorhabditis bacteriophora and Metarhizium anisopliae. Differentially expressed transcripts in common between Bt and entomopathogen treatments encode proteins in general stress response pathways, including putative Bt binding receptors from the ATP binding cassette transporter superfamily. Putative caspases, pro- and anti-apoptotic factors, as well as endoplasmic reticulum (ER) stress-response factors were identified among transcripts uniquely up-regulated following exposure to either Bt protein. CONCLUSIONS: Our study suggests that the up-regulation of genes involved in ER stress management and apoptotic progression may be important in determining cell fate following exposure of susceptible D. v. virgifera larvae to Bt maize roots. This study provides novel insights into insect response to Bt intoxication, and a possible framework for future investigations of resistance mechanisms.


Asunto(s)
Bacillus thuringiensis , Escarabajos , Plaguicidas , Animales , Bacillus thuringiensis/genética , Supervivencia Celular , Escarabajos/genética , Endotoxinas/toxicidad , Resistencia a los Insecticidas , Larva/genética , Control Biológico de Vectores , Plantas Modificadas Genéticamente/genética , Regulación hacia Arriba , Zea mays/genética
13.
Curr Protoc ; 1(9): e231, 2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-34491623

RESUMEN

The use of whole animal models in toxicological studies is essential for understanding the physiological responses caused by chemical exposures. However, such studies can face reproducibility challenges due to unaccounted experimental parameters that can have a marked influence on toxicological outcomes. Zebrafish embryos and larvae are a popular vertebrate animal model for studying cellular, tissue, and organ responses to toxicant exposures. Despite the popularity of this system, standardized protocols that control for the influence of various experimental parameters and culture conditions on the toxicological response in these animals have not been widely adopted, making it difficult to compare findings from different laboratories. Here, we describe a detailed approach for designing and optimizing protocols to assess the impact of chemical exposures on the development and survival of zebrafish embryos and larvae. We first describe our standard procedure to determine two key toxicological thresholds, the maximum tolerable concentration (MTC) and the lethal concentration (LC50 , defined as that in which 50% of larvae die), in response to an exposure that persists from early development through larval maturation. We then describe two protocols to systematically test how key experimental parameters, including genetic background, culture media, animal density, volume, plate material, and developmental stage in which the embryos are exposed, alter the MTC and LC50 . Finally, we provide a step-by-step guide to assess the interaction between two chemicals using this model. These protocols will guide the standardization of toxicological studies using zebrafish and maximize reproducibility. © 2021 Wiley Periodicals LLC. Basic Protocol 1: Zebrafish embryo collection and culture, and establishment of the MTC and LC50 Basic Protocol 2: Evaluation of the impact of culture conditions on toxicant responses of zebrafish embryo and larvae Basic Protocol 3: Identification of the developmental window of sensitivity to toxicant exposure Basic Protocol 4: Testing interaction between multiple toxicants.


Asunto(s)
Contaminantes Químicos del Agua , Pez Cebra , Animales , Larva , Dosificación Letal Mediana , Reproducibilidad de los Resultados
14.
Zool Res ; 42(5): 637-649, 2021 Sep 18.
Artículo en Inglés | MEDLINE | ID: mdl-34472225

RESUMEN

The insect brain is the central part of the neurosecretory system, which controls morphology, physiology, and behavior during the insect's lifecycle. Lepidoptera are holometabolous insects, and their brains develop during the larval period and metamorphosis into the adult form. As the only fully domesticated insect, the Lepidoptera silkworm Bombyx mori experienced changes in larval brain morphology and certain behaviors during the domestication process. Hormonal regulation in insects is a key factor in multiple processes. However, how juvenile hormone (JH) signals regulate brain development in Lepidoptera species, especially in the larval stage, remains elusive. We recently identified the JH receptor Methoprene tolerant 1 ( Met1) as a putative domestication gene. How artificial selection on Met1 impacts brain and behavioral domestication is another important issue addressing Darwin's theory on domestication. Here, CRISPR/Cas9-mediated knockout of Bombyx Met1 caused developmental retardation in the brain, unlike precocious pupation of the cuticle. At the whole transcriptome level, the ecdysteroid (20-hydroxyecdysone, 20E) signaling and downstream pathways were overactivated in the mutant cuticle but not in the brain. Pathways related to cell proliferation and specialization processes, such as extracellular matrix (ECM)-receptor interaction and tyrosine metabolism pathways, were suppressed in the brain. Molecular evolutionary analysis and in vitro assay identified an amino acid replacement located in a novel motif under positive selection in B. mori, which decreased transcriptional binding activity. The B. mori MET1 protein showed a changed structure and dynamic features, as well as a weakened co-expression gene network, compared with B. mandarina. Based on comparative transcriptomic analyses, we proposed a pathway downstream of JH signaling (i.e., tyrosine metabolism pathway) that likely contributed to silkworm larval brain development and domestication and highlighted the importance of the biogenic amine system in larval evolution during silkworm domestication.


Asunto(s)
Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Bombyx/metabolismo , Proteínas de Insectos/metabolismo , Hormonas Juveniles/metabolismo , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Bombyx/crecimiento & desarrollo , Encéfalo/crecimiento & desarrollo , Encéfalo/metabolismo , Sistemas CRISPR-Cas , Eliminación de Gen , Regulación del Desarrollo de la Expresión Génica , Genotipo , Proteínas de Insectos/genética , Integumento Común/fisiología , Larva/crecimiento & desarrollo , Larva/metabolismo , Filogenia , Conformación Proteica
15.
Environ Monit Assess ; 193(10): 665, 2021 Sep 20.
Artículo en Inglés | MEDLINE | ID: mdl-34545435

RESUMEN

Aedes aegypti is an important vector of dengue fever, dengue hemorrhagic fever and yellow fever, chikungunya, and Zika virus. The objective was to evaluate the resistance of A. aegypti exposed to insecticides with different action modes (deltamethrin, imidacloprid, and fipronil) under intense selection pressure for 10 generations in laboratory. Bioassays were conducted according to World Health Organization. Biochemical assay performed after selection with deltamethrin (Delta-SEL), fipronil (Fipro-SEL), and imidacloprid (Imida-SEL) from G1 to G10 was used for the assessment of detoxification enzymes (esterase (EST), acetylcholinesterase (AChE), glutathione S-transferases (GST), and acid and alkaline phosphatases (ACP and ALP)). The Fipro-SEL (G10) had high resistance (77-fold), whereas Delta-SEL and Imida-SEL populations presented very high resistance with 118 and 372-fold, respectively, in comparison with unselected (UNSEL). The levels of EST, AChE, GST, ACP, and ALP enzymes amplified on application from G1 to G10. The enzymes contributing in resistance development of insecticides were as follows: GST (20.7 µmol/min/mg of protein) in Delta-SEL (G10), while AChE 9.71 µmol/min/mg of protein in Imida-SEL (G10) and the peak ACP and ALP enzyme activities 13.32 and 12.93 µmol/min/mg of protein, respectively, in Fipro-SEL (G10). The results showed that detoxification enzymes trigger insecticide resistance in A. aegypti and their suppression may aid in the resistance breakage.


Asunto(s)
Aedes , Insecticidas , Piretrinas , Infección por el Virus Zika , Virus Zika , Acetilcolinesterasa , Animales , Monitoreo del Ambiente , Insecticidas/toxicidad , Larva , Mosquitos Vectores , Neonicotinoides , Nitrilos , Nitrocompuestos , Pirazoles , Piretrinas/toxicidad
16.
Zhongguo Xue Xi Chong Bing Fang Zhi Za Zhi ; 33(4): 387-395, 2021 Aug 24.
Artículo en Chino | MEDLINE | ID: mdl-34505446

RESUMEN

OBJECTIVE: To analyze the changes of small molecular metabolites in the larvae of a deltamethrin-sensitive strain of Anopheles sinensis following exposure to deltamethrin, so as to provide the scientific basis for investigating the metabolic pathway and screening metabolic markers of deltamethrin in An. sinensis. METHODS: The 50% and 75% lethal concentrations (LC50 and LC75) of deltamethrin against the larvae of a deltamethrin-sensitive strain of An. sinensis were calculated in laboratory. The type and content of An. sinensis larvae metabolites were detected using high performance liquid chromatography and mass spectrometry (LC-MS/MS) following exposure to deltamethrin at LC50 and LC75 for 30 min and 24 h, and the changes of metabolites were analyzed. RESULTS: The LC50 and LC75 values of deltamethrin were 4.36 × 10-3 µg/mL and 1.12 × 10-2 µg/mL against thelarvae of a deltamethrin-sensitive strain of An. sinensis. Following exposure of the larvae of a deltamethrin-sensitive strain of An. sinensis to deltamethrin at LC50 and LC75 for 30 min, the differential metabolites mainly included organic oxygen compounds, carboxylic acid and its derivatives, fatty acyl and pyrimidine nucleotides, with reduced glucose levels. Following exposure for 24 h, the differential metabolites mainly included organic oxygen compounds, carboxylic acid and its derivatives, aliphatic acyl and purine nucleotides, with increased glucose level detected. CONCLUSIONS: Carbohydrate, carboxylic acid and its derivatives, fatty acyls, amino acids and their derivatives may play important roles in deltamethrin metabolism in the larvae of a deltamethrin-sensitive strain of An. sinensis.


Asunto(s)
Anopheles , Insecticidas , Animales , Cromatografía Liquida , Larva , Nitrilos , Piretrinas , Espectrometría de Masas en Tándem
17.
J Chem Ecol ; 47(8-9): 747-754, 2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-34550513

RESUMEN

Plant Growth-Promoting Rhizobacteria (PGPR) induce systemic resistance (SR) in plants, decreasing the development of phytopathogens. The FZB42 strain of Bacillus velezensis is known to induce an SR against pathogens in various plant species. Previous studies suggested that it could also influence the interactions between plants and associated pests. However, insects have developed several strategies to counteract plant defenses, including salivary proteins that allow the insect escaping detection, manipulating defensive pathways to its advantage, deactivating early signaling processes, or detoxifying secondary metabolites. Because Brown Marmorated Stink Bug (BMSB) Halyomorpha halys is highly invasive and polyphagous, we hypothesized that it could detect the PGPR-induced systemic defenses in the plant, and efficiently adapt its salivary compounds to counteract them. Therefore, we inoculated a beneficial rhizobacterium on Vicia faba roots and soil, previous to plant infestation with BMSB. Salivary gland proteome of BMSB was analyzed by LC-MS/MS and a label-free quantitative proteomic method. Among the differentially expressed proteins, most were up-regulated in salivary glands of insects exposed to PGPR-treated plants for 24 h. We could confirm that BMSB was confronted with a stress during feeding on PGPR-treated plants. The to-be-confirmed defensive state of the plant would have been rapidly detected by the invasive H. halys pest, which consequently modified its salivary proteins. Among the up-regulated proteins, many could be associated with a role in plant defense counteraction, and more especially in allelochemicals detoxification or sequestration.


Asunto(s)
Bacillus/crecimiento & desarrollo , Heterópteros/metabolismo , Proteínas y Péptidos Salivales/análisis , Vicia faba/microbiología , Animales , Cromatografía Líquida de Alta Presión , Heterópteros/crecimiento & desarrollo , Larva/metabolismo , Glándulas Salivales/metabolismo , Estrés Fisiológico , Espectrometría de Masas en Tándem , Regulación hacia Arriba , Vicia faba/química , Vicia faba/parasitología
18.
Acta Crystallogr C Struct Chem ; 77(Pt 9): 505-512, 2021 09 01.
Artículo en Inglés | MEDLINE | ID: mdl-34482293

RESUMEN

A chemical study of the hydro-ethanol extract of the leaves of Combretum glutinosum resulted in the isolation of nine compounds, including 5-demethylsinensetin (1), umuhengerin (2), (20S,24R)-ocotillone (3), lupeol (4), ß-sitosterol (5), oleanolic acid (6), betulinic acid (7), corymbosin (8) and ß-sitosterol glucoside (9). Four compounds have been isolated for the first time from the genus Combretum [viz. (1), (2), (3) and (8)]. The crystal structures of flavonoid (2), C20H20O8, Z' = 2, and triterpene (3), C30H50O3, Z' = 1, have been determined for the first time; the latter confirmed the absolute configuration of native (20S,24R)-ocotillone previously derived from the crystal structures of related derivatives. The molecules of (3) are linked into supramolecular chains by intermolecular O-H...O hydrogen bonds. The crude extracts obtained by aqueous decoction and hydro-ethanolic maceration, as well as the nine isolated compounds, were tested for their anthelmintic activity on the larvae and adult worms of Haemonchus contortus, a hematophage that causes parasitic disorders in small ruminants. The evaluated anthelmintic activity showed that the extracts at different doses, as well as all the compounds tested at 150 µg ml-1, inhibited the migration of the larvae and the motility of the adult worms of the parasite compared with the phosphate buffer solution negative reference control. The best activity was obtained with flavonoids (1), (2) and (8) on both stages of the parasite. The flavones that showed good activity can be used for the further development of other derivatives, which could increase the anthelmintic efficacy.


Asunto(s)
Antihelmínticos/farmacología , Antiinfecciosos/farmacología , Combretaceae/efectos de los fármacos , Combretum/química , Flavonas/farmacología , Flavonoides/química , Haemonchus/efectos de los fármacos , Larva/efectos de los fármacos , Hojas de la Planta/efectos de los fármacos , Animales , Antihelmínticos/química , Antihelmínticos/uso terapéutico , Antiinfecciosos/química , Cristalografía por Rayos X , Flavonas/química , Flavonoides/farmacología , Haemonchus/crecimiento & desarrollo , Enlace de Hidrógeno , Hojas de la Planta/química
19.
Lab Chip ; 21(18): 3420-3428, 2021 09 14.
Artículo en Inglés | MEDLINE | ID: mdl-34486609

RESUMEN

Volumetric imaging of dynamic signals in a large, moving, and light-scattering specimen is extremely challenging, owing to the requirement on high spatiotemporal resolution and difficulty in obtaining high-contrast signals. Here we report that through combining a microfluidic chip-enabled digital scanning light-sheet illumination strategy with deep-learning based image restoration, we can realize isotropic 3D imaging of a whole crawling Drosophila larva on an ordinary inverted microscope at a single-cell resolution and a high volumetric imaging rate up to 20 Hz. Enabled with high performances even unmet by current standard light-sheet fluorescence microscopes, we in toto record the neural activities during the forward and backward crawling of a 1st instar larva, and successfully correlate the calcium spiking of motor neurons with the locomotion patterns.


Asunto(s)
Aprendizaje Profundo , Microscopía , Animales , Drosophila , Procesamiento de Imagen Asistido por Computador , Imagenología Tridimensional , Larva
20.
J Insect Sci ; 21(5)2021 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-34536079

RESUMEN

Native to the neotropics, the avocado seed moth Stenoma catenifer Walsingham (Lepidoptera: Elachistidae) is a specialist pest of the family Lauraceae and considered one of the most important pests of avocados worldwide. However, little is known regarding its spatial distribution within a single tree. Therefore, we designed a study to evaluate the effects of canopy height and aspect (i.e., side of the tree) on fruit infestation by S. catenifer larvae in avocados. The study was conducted in three commercial organic avocado orchards located in São Paulo, Brazil. At each orchard, 40 fruit from 30 random trees were sampled weekly from October 2017 through February 2018, evaluating the number of fruits infested by S. catenifer larvae at three tree heights (bottom, middle, and top). In addition, fruits on the ground were also sampled. We also evaluated the effect of the side of the tree where the fruits were collected, i.e., whether they were on the side facing the east (sunrise) or the west (sunset). Within the avocado canopy, the level of fruit infestation by S. catenifer larvae was significantly higher at the top of the trees than in the middle and bottom. Fruit on the ground had lower levels of infestation than those on the tree canopy. The level of fruit infestation was also higher on the side of avocado trees facing the east (sunrise). Understanding the within-tree distribution of S. catenifer will help to better target monitoring and control activities against this pest in avocados.


Asunto(s)
Demografía , Mariposas Nocturnas/fisiología , Animales , Frutas , Control de Insectos/métodos , Larva/efectos de los fármacos , Larva/fisiología , Persea , Árboles
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