Search results for " Insect"
showing 10 items of 280 documents
Roving Robots Gain from an Orientation Algorithm of Fruit Flies and Predict a Fly Decision-Making Algorithm
2014
Simple organisms like bacteria are directly influenced by momentary changes in concentration or strength of sensory signals. In noisy sensory gradients frequent zigzagging reduces the performance of the cell or organism. Drosophila melanogaster flies significantly deviate from a direct response to sensory input when orienting in gradients. A dynamical model has been derived which reproduces fly behaviour. Here we report on an emergent property of the model. Implemented in a robot, the algorithm is sustaining decisions between visual targets. The behaviour was consequently found in wild-type flies, which stay with a once-chosen visual target for considerable longer times than mutant flies wi…
Seasonal gene expression kinetics between diapause phases in Drosophila virilis group species and overwintering differences between diapausing and no…
2015
AbstractMost northern insect species experience a period of developmental arrest, diapause, which enables them to survive over the winter and postpone reproduction until favorable conditions. We studied the timing of reproductive diapause and its long-term effects on the cold tolerance of Drosophila montana, D. littoralis and D. ezoana females in seasonally varying environmental conditions. At the same time we traced expression levels of 219 genes in D. montana using a custom-made microarray. We show that the seasonal switch to reproductive diapause occurs over a short time period and that overwintering in reproductive diapause has long-lasting effects on cold tolerance. Some genes, such as…
Structure of the phenylalanine hydroxylase gene in Drosophila melanogaster and evidence of alternative promoter usage.
1996
The complete Drosophila melanogaster phenylalanine hydroxylase gene isolated from a genomic library was sequenced. Gene structure consisted of five exons covering a region of around 3 kb. Position of introns in the C-terminal domain was conserved with mammalian aromatic amino acid hydroxylase genes. Putative promoter sequences in the 5'UTR and intron 1 were identified. A novel transcript was detected differing from that previously reported by the inclusion of a part of the intron 1 sequence. It could be produced using an alternative promoter. The deduced open reading frame would code a protein with a small difference at the N-terminus. Expression of the alternative transcripts was examined …
The Carpathians as a Major Diversity Hotspot in Europe
2011
The Carpathians are one of the major mountain ranges of Europe, but still one of its least studied regions. It is increasingly recognized that they played a major role in the formation and Pleistocene survival of numerous continental, arctic, and arctic–alpine taxa. Many endemic taxa have been described from these mountains. The number of phylogeographic/phylogenetic studies covering at least partially the Carpathians is also increasing. These studies reveal unevenly distributed genetic and taxonomic diversity. In this work, we analyse population genetic structures in the Carpathians revealed by case studies on aquatic insects, comparing them to existing literature data on plants, butterfli…
A new gene superfamily of pathogen-response (repat) genes in Lepidoptera: Classification and expression analysis
2012
Repat (REsponse to PAThogens) genes were first identified in the midgut of Spodoptera exigua (Lepidoptera: Noctuidae) in response to Bacillus thuringiensis and baculovirus exposure. Since then, additional repat gene homologs have been identified in different studies. In this study the comprehensive larval transcriptome from S. exigua was analyzed for the presence of novel repat-homolog sequences. These analyses revealed the presence of at least 46 repat genes in S. exigua, establishing a new gene superfamily in this species. Phylogenetic analysis and studies of conserved motifs in these hypothetical proteins have allowed their classification in two main classes, αREPAT and βREPAT. Studies o…
Paratransgenic manipulation of a tsetse microRNA alters the physiological homeostasis of the fly’s midgut environment
2021
Tsetse flies are vectors of parasitic African trypanosomes, the etiological agents of human and animal African trypanosomoses. Current disease control methods include fly-repelling pesticides, fly trapping, and chemotherapeutic treatment of infected people and animals. Inhibiting tsetse’s ability to transmit trypanosomes by strengthening the fly’s natural barriers can serve as an alternative approach to reduce disease. The peritrophic matrix (PM) is a chitinous and proteinaceous barrier that lines the insect midgut and serves as a protective barrier that inhibits infection with pathogens. African trypanosomes must cross tsetse’s PM in order to establish an infection in the fly, and PM struc…
The transcriptome of Spodoptera exigua larvae exposed to different types of microbes.
2012
We have obtained and characterized the transcriptome of Spodoptera exigua larvae with special emphasis on pathogen-induced genes. In order to obtain a highly representative transcriptome, we have pooled RNA from diverse insect colonies, conditions and tissues. Sequenced cDNA included samples from 3 geographically different colonies. Enrichment of RNA from pathogen-related genes was accomplished by exposing larvae to different pathogenic and non-pathogenic microbial agents such as the bacteria Bacillus thuringiensis, Micrococcus luteus, and Escherichia coli, the yeast Saccharomyces cerevisiae, and the S. exigua nucleopolyhedrovirus (SeMNPV). In addition, to avoid the loss of tissue-specific …
Degradation and acute toxicity of Methidathion and Trichlorfon onProcambarus clarkii,in experimental conditions
1991
Routine applications of organophosphate pesticides may adversely affect many nontarget organisms. Static toxicities in mature crayfish Procambarus clarkii were determined, in laboratory, for two organophosphate insecticides using 24, 48, 72 and 96‐h static tests. Three groups of 10 crayfish were exposed to 0.75 to 6 ppm for Trichlorfon and 0.2 to 0.9 ppm for Methidathion. The 24 to 96‐h LC50 values for Trichlorfon and Methidathion were from 5.14–0.99 ppm and 0.73–0.28 ppm respectively. Studies of degradation of Methidathion and Trichlorfon have been made using 1 ppm for Methidathion and 0.1 ppm for Trichlorfon. Both insecticides were degradated gradually until 96‐h. Results show that Methid…
Expression profiling of glial genes during Drosophila embryogenesis
2006
AbstractIn the central nervous system of Drosophila, the induction of the glial cell fate is dependent on the transcription factor glial cells missing (gcm). Though a considerable number of other genes have been shown to be expressed in all or in subsets of glial cells, the course of glial cell differentiation and subtype specification is only poorly understood. This prompted us to design a whole genome microarray approach comparing gcm gain-of-function and, for the first time, gcm loss-of-function genetics to wildtype in time course experiments along embryogenesis. The microarray data were analyzed with special emphasis on the temporal profile of differential regulation. A comparison of bo…
Pre-invasion history and demography shape the genetic variation in the insecticide resistance-related acetylcholinesterase 2 gene in the invasive Col…
2012
Abstract Background Invasive pest species offers a unique opportunity to study the effects of genetic architecture, demography and selection on patterns of genetic variability. Invasive Colorado potato beetle (Leptinotarsa decemlineata) populations have experienced a rapid range expansion and intense selection by insecticides. By comparing native and invasive beetle populations, we studied the origins of organophosphate (OP) resistance-associated mutations in the acetylcholinesterase 2 (AChE2) gene, and the role of selection and demography on its genetic variability. Results Analysis of three Mexican, two US and five European populations yielded a total of 49 haplotypes. Contrary to the exp…