45 research outputs found
Viral Paratransgenesis in the Malaria Vector Anopheles gambiae
Paratransgenesis, the genetic manipulation of insect symbiotic microorganisms, is being considered as a potential method to control vector-borne diseases such as malaria. The feasibility of paratransgenic malaria control has been hampered by the lack of candidate symbiotic microorganisms for the major vector Anopheles gambiae. In other systems, densonucleosis viruses (DNVs) are attractive agents for viral paratransgenesis because they infect important vector insects, can be genetically manipulated and are transmitted to subsequent generations. However, An. gambiae has been shown to be refractory to DNV dissemination. We discovered, cloned and characterized the first known DNV (AgDNV) capable of infection and dissemination in An. gambiae. We developed a flexible AgDNV-based expression vector to express any gene of interest in An. gambiae using a two-plasmid helper-transducer system. To demonstrate proof-of-concept of the viral paratransgenesis strategy, we used this system to transduce expression of an exogenous gene (enhanced green fluorescent protein; EGFP) in An. gambiae mosquitoes. Wild-type and EGFP-transducing AgDNV virions were highly infectious to An. gambiae larvae, disseminated to and expressed EGFP in epidemiologically relevant adult tissues such as midgut, fat body and ovaries and were transmitted to subsequent mosquito generations. These proof-of-principle data suggest that AgDNV could be used as part of a paratransgenic malaria control strategy by transduction of anti-Plasmodium peptides or insect-specific toxins in Anopheles mosquitoes. AgDNV will also be extremely valuable as an effective and easy-to-use laboratory tool for transient gene expression or RNAi in An. gambiae
High spatial and temporal resolution wide-field imaging of neuron activity using quantum NV-diamond
A quantitative understanding of the dynamics of biological neural networks is fundamental to gaining insight into information processing in the brain. While techniques exist to measure spatial or temporal properties of these networks, it remains a significant challenge to resolve the neural dynamics with subcellular spatial resolution. In this work we consider a fundamentally new form of wide-field imaging for neuronal networks based on the nanoscale magnetic field sensing properties of optically active spins in a diamond substrate. We analyse the sensitivity of the system to the magnetic field generated by an axon transmembrane potential and confirm these predictions experimentally using electronically-generated neuron signals. By numerical simulation of the time dependent transmembrane potential of a morphologically reconstructed hippocampal CA1 pyramidal neuron, we show that the imaging system is capable of imaging planar neuron activity non-invasively at millisecond temporal resolution and micron spatial resolution over wide-fields
Effects of Sasobit® content on the rheological characteristics of unaged and aged asphalt binders at high and intermediate temperatures
Fauna of Noctuidae (Lepidoptera: Noctuoidea) in a pasture area in Altamira, Eastern Amazon, Par\ue1, Brazil
Fauna of Noctuidae (Lepidoptera: Noctuoidea) in a pasture area in Altamira, Eastern Amazon, Pará, Brazil
This study evaluated the nocturnal fauna of Noctuidae in a pasture area in Altamira, Pará. Samples were collected monthly for two nights at the new moon period, from August 2007 to July 2008. We collected a total of 345 specimens (N) of 66 species (S). The most abundant species were Ptichodes basilans (Guenée) (n = 87), Leucania jaliscana (Schaus), Spodoptera frugiperda (JE Smith) (n = 28) and Argidia palmipes Guenée (n = 21). For the entire period, the following indexes were found: Shannon diversity H′= 3.20 and Brillouin H = 2.94, evenness of Shannon E′= 0.76 and Brillouin E= 0.76, and Berger-Parker dominance BP= 0.252. The greatest diversity was found in the dry season. According to the estimates of species richness, it is possible that between 14 to 72 more species exist in the region