RESUMO
Electropenetrography (EPG) has been used for many years to visualize unseen stylet probing behaviors of plant-feeding piercing-sucking insects, primarily hemipterans. Yet, EPG has not been extensively used with blood-feeding insects. In this study, an AC-DC electropenetrograph with variable input resistors (Ri), i.e., amplifier sensitivities, was used to construct a waveform library for the mosquito arbovirus vector, Aedes aegypti (Linneaus), while feeding on human hands. EPG waveforms representing feeding activities were: 1) electrically characterized, 2) defined by visual observation of biological activities, 3) analyzed for differences in appearance by Ri level and type of applied signal (AC or DC), and 4) quantified. Electrical origins of waveforms were identified from five different Ri levels and AC versus DC. Mosquitoes produced short stylet probes ('bites') that typically contained five waveform families. Behaviors occurred in the following order: surface salivation (waveform family J), stylet penetration through the outer skin (K), penetration of deeper tissues and location of blood vessels/pathway activities (L), active ingestion with engorgement (M), and an unknown behavior that terminated the probe (N). Only K, L, and M were performed by every insect. A kinetogram of conditional probabilities for waveform performance demonstrated plasticity among individuals in L and M, which were alternated. Now that EPG waveforms for mosquito feeding have been defined, EPG can be used as a tool for improved biological understanding of mosquito-borne diseases.
Assuntos
Aedes/fisiologia , Animais , Fenômenos Eletrofisiológicos , Comportamento Alimentar , FemininoRESUMO
The Great Plains of the United States is a region comprised of approximately 45 million hectares of grasslands where several economically important cereal crops are grown. Arthropod-transmitted, cereal-infecting viruses vary in incidence from year-to-year and are often difficult to detect in large acreages. To facilitate the detection of economically important viruses of cereals that often exist in co-infections, a multiplex reverse transcriptase PCR (RT-PCR) platform assay was developed. This method can be used in combination with high resolution melting (HRM) to detect and allow for discrimination between three arthropod-transmitted plant viruses; Wheat streak mosaic virus (WSMV), Maize mosaic virus (MMV) and Barley yellow dwarf virus (BYDV). Multiplex PCR in combination with HRM allowed for successful detection of WSMV, MMV, and BYDV, as well as discrimination between three BYDV species, BYDV-PAS, BYDV-PAV and BYDV-MAV. All primer pairs amplified products of the predicted size. The BYDV-RT-PCR primers amplified products of identical length for all three species of BYDV. HRM was then used to discriminate between these products by determining significant differences between the melting rates for each (p < 0.05). This study demonstrates the flexibility of combining multiplex PCR with HRM to increase the specificity of plant virus diagnostics based on the needs of the diagnostician performing the assay.
Assuntos
Artrópodes/virologia , Grão Comestível/virologia , Reação em Cadeia da Polimerase Multiplex/métodos , Vírus de Plantas/isolamento & purificação , Animais , Primers do DNA/genética , Doenças das Plantas/virologia , Vírus de Plantas/genética , Sensibilidade e Especificidade , Temperatura de TransiçãoRESUMO
Phytopathogenic spiroplasmas can multiply in vascular plants and insects. A deeper understanding of this dual-host life could be furthered through the identification by random mutagenesis of spiroplasma genes required. The ability of the EZ::TN™