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Michael J Lehane

Publications and source records attributed to Michael J Lehane.

9 recordsLinked to original sources
PubMed2006

Determinants of vector specificity of o'nyong nyong and chikungunya viruses in Anopheles and Aedes mosquitoes.

The alphaviruses o'nyong nyong virus (ONNV) and chikungunya virus (CHIKV) provide a unique system to study the viral genes involved in vector specificity. ONNV infects both anopheline and culicine mosquitoes, whereas CHIKV infects only culicine mosquitoes. In this study, chimeric viruses were constructed that contained genes from both ONNV and CHIKV. These chimeras and previously described full-length infectious clones of ONNV and CHIKV were evaluated in Anopheles gambiae and Aedes aegypti mosquitoes. Virus derived from the infectious clones of ONNV and CHIKV retained the vector specificity of the parental viruses. All six of the chimeras were found to infect Ae. aegypti mosquitoes at high rates but only the chimera containing viral genes encoding all of the structural proteins of ONNV was able to infect An. gambiae mosquitoes. These data indicate that all of the viral structural proteins are necessary for ONNV to infect An. gambiae mosquitoes.

Aedes↗
PubMed2005

Development and characterization of a double subgenomic chikungunya virus infectious clone to express heterologous genes in Aedes aegypti mosquitoes.

Three full-length infectious cDNA clones based on the alphavirus chikungunya (CHIKV) were developed and characterized in vitro and in vivo. The full-length clone retained the viral phenotypes of CHIKV in both cell culture and in mosquitoes and should be a valuable tool for the study of virus interactions in an epidemiologically significant natural vector, Aedes aegypti. Two additional infectious clones were constructed that express green fluorescent protein (EGFP) in the midgut, salivary glands, and nervous tissue of Aedes aegypti mosquitoes following oral infection. The two constructs differed in the placement of the subgenomic promoter and the gene encoding EGFP. Viruses derived from the pCHIKic EGFP constructs (5' CHIKV EGFP and 3' CHIKV EGFP) expressed EGFP in 100% of the Ae. aegypti mosquitoes tested on days 7 and 14 post infection (p.i.). The 5' CHIKV EGFP disseminated to 90% of the salivary glands and nervous tissue by day 14 p.i. Dissemination rates of this new viral vector exceeds those of previous systems, thus expanding the repertoire and potential for gene expression studies on this important vector species.

Aedes↗
PubMed2005

A case for a Glossina genome project.

Given the medical and agricultural significance of Glossina, knowledge of the genomic aspects of the vector and vector-pathogen interactions are a high priority. In preparation for a full genome sequence initiative, an extensive set of expressed sequence tags (ESTs) has been generated from tissue-specific normalized libraries. In addition, bacterial artificial chromosome (BAC) libraries are being constructed, and information on the genome structure and size from different species has been obtained. An international consortium is now in place to further efforts to lead to a full genome project.

Animals↗
PubMed2005

Differential infectivities of o'nyong-nyong and chikungunya virus isolates in Anopheles gambiae and Aedes aegypti mosquitoes.

O'nyong-nyong virus (ONNV) and chikungunya virus (CHIKV) are closely related alphaviruses that cause human disease in Africa and Asia. Like most alphaviruses, CHIKV is vectored by culicine mosquitoes. ONNV is considered unusual as it primarily infects anopheline mosquitoes; however, there are relatively few experimental data to support this. In this study, three strains of ONNV and one strain of CHIKV were evaluated in Anopheles gambiae and Aedes aegypti mosquitoes and in four cell lines. As predicted, CHIKV was not infectious to An. gambiae, and we observed strain-variability for ONNV with respect to the ability of the virus to infect An. gambiae and Ae. aegypti. The species specificity in vivo was reflected by in vitro experiments using culicine and anopheline-derived cell lines.

Aedes↗
PubMed2004

Immune responses and parasite transmission in blood-feeding insects.

The detailed model of insect immunity being built for Drosophila, allied to mass sequencing programs for blood-feeding insects, has led to advances in our understanding of the interaction between pathogens and insect vectors. An outline of insect immunity is given here based on the Drosophila studies, which is used as a framework to discuss recent work on Plasmodium-mosquito and Trypanosoma-tsetse interactions.

Animals↗
PubMed2003

Interactions between tsetse and trypanosomes with implications for the control of trypanosomiasis.

Tsetse flies (Diptera: Glossinidae) are vectors of several species of pathogenic trypanosomes in tropical Africa. Human African trypanosomiasis (HAT) is a zoonosis caused by Trypanosoma brucei rhodesiense in East Africa and T. b. gambiense in West and Central Africa. About 100000 new cases are reported per year, with many more probably remaining undetected. Sixty million people living in 36 countries are at risk of infection. Recently, T. b. gambiense trypanosomiasis has emerged as a major public health problem in Central Africa, especially in the Democratic Republic of Congo, Angola and southern Sudan where civil war has hampered control efforts. African trypanosomes also cause nagana in livestock. T. vivax and T. congolense are major pathogens of cattle and other ruminants, while T. simiae causes high mortality in domestic pigs; T. brucei affects all livestock, with particularly severe effects in equines and dogs. Central to the control of these diseases is control of the tsetse vector, which should be very effective since trypanosomes rely on this single insect for transmission. However, the area infested by tsetse has increased in the past century. Recent advances in molecular technologies and their application to insects have revolutionized the field of vector biology, and there is hope that such new approaches may form the basis for future tsetse control strategies. This article reviews the known biology of trypanosome development in the fly in the context of the physiology of the digestive system and interactions of the immune defences and symbiotic flora.

Animals↗
PubMed2003

Post-integration behavior of a Mos1 mariner gene vector in Aedes aegypti.

The post-integration behavior of insect gene vectors will determine the types of applications for which they can be used. Transposon mutagenesis, enhancer trapping, and the use of transposable elements as genetic drive systems in insects requires transposable elements with high rates of remobilization in the presence of transposase. We investigated the post-integration behavior of the Mos1 mariner element in transgenic Aedes aegypti by examining both germ-line and somatic transpositions of a non-autonomous element in the presence of Mos1 transposase. Somatic transpositions were occasionally detected while germ-line transposition was only rarely observed. Only a single germ-line transposition event was recovered after screening 14,000 progeny. The observed patterns of transposition suggest that Mos1 movement takes place between the S phase and anaphase. The data reported here indicate that Mos1 will be a useful vector in Ae. aegypti for applications requiring a very high degree of vector stability but will have limited use in the construction of genetic drive, enhancer trap, or transposon tagging systems in this species.

Aedes↗
PubMed2003

Gene vector and transposable element behavior in mosquitoes.

The development of efficient germ-line transformation technologies for mosquitoes has increased the ability of entomologists to find, isolate and analyze genes. The utility of the currently available systems will be determined by a number of factors including the behavior of the gene vectors during the initial integration event and their behavior after chromosomal integration. Post-integration behavior will determine whether the transposable elements being employed currently as primary gene vectors will be useful as gene-tagging and enhancer-trapping agents. The post-integration behavior of existing insect vectors has not been extensively examined. Mos1 is useful as a primary germ-line transformation vector in insects but is inefficiently remobilized in Drosophila melanogaster and Aedes aegypti. Hermes transforms D. melanogaster efficiently and can be remobilized in this species. This element is also useful for creating transgenic A. aegypti, but its mode of integration in mosquitoes results in the insertion of flanking plasmid DNA. Hermes can be remobilized in the soma of A. aegypti and transposes using a common cut-and-paste mechanism; however, the element does not remobilize in the germ line. piggyBac can be used to create transgenic mosquitoes and occasionally integrates using a mechanism other than a simple cut-and-paste mechanism. Preliminary data suggest that remobilization is infrequent. Minos also functions in mosquitoes and, like the other gene vectors, appears to remobilize inefficiently following integration. These results have implications for future gene vector development efforts and applications.

Animals↗