Search results for "Insect Science"
showing 10 items of 1011 documents
CD8 T Cells Control Cytomegalovirus Latency by Epitope-Specific Sensing of Transcriptional Reactivation
2006
ABSTRACT During murine cytomegalovirus (mCMV) latency in the lungs, most of the viral genomes are transcriptionally silent at the major immediate-early locus, but rare and stochastic episodes of desilencing lead to the expression of IE1 transcripts. This low-frequency but perpetual expression is accompanied by an activation of lung-resident effector-memory CD8 T cells specific for the antigenic peptide 168-YPHFMPTNL-176, which is derivedfrom the IE1 protein. These molecular and immunological findings were combined in the “silencing/desilencing and immune sensing hypothesis” of cytomegalovirus latency and reactivation. This hypothesis proposes that IE1 gene expression proceeds to cell surfac…
Transactivation of cellular genes involved in nucleotide metabolism by the regulatory IE1 protein of murine cytomegalovirus is not critical for viral…
2008
ABSTRACT Despite its high coding capacity, murine CMV (mCMV) does not encode functional enzymes for nucleotide biosynthesis. It thus depends on cellular enzymes, such as ribonucleotide reductase (RNR) and thymidylate synthase (TS), to be supplied with deoxynucleoside triphosphates (dNTPs) for its DNA replication. Viral transactivation of these cellular genes in quiescent cells of host tissues is therefore a parameter of viral fitness relevant to pathogenicity. Previous work has shown that the IE1, but not the IE3, protein of mCMV transactivates RNR and TS gene promoters and has revealed an in vivo attenuation of the mutant virus mCMV-ΔIE1. It was attractive to propose the hypothesis that la…
Honeybees can recognise images of complex natural scenes for use as potential landmarks
2008
SUMMARY The ability to navigate long distances to find rewarding flowers and return home is a key factor in the survival of honeybees (Apis mellifera). To reliably perform this task, bees combine both odometric and landmark cues,which potentially creates a dilemma since environments rich in odometric cues might be poor in salient landmark cues, and vice versa. In the present study, honeybees were provided with differential conditioning to images of complex natural scenes, in order to determine if they could reliably learn to discriminate between very similar scenes, and to recognise a learnt scene from a novel distractor scene. Choices made by individual bees were modelled with signal detec…
Potential impact of genetically modified Lepidoptera-resistant Brassica napus in biodiversity hotspots: Sicily as a theoretical model
2016
The general increase of the cultivation and trade of Bt transgenic plants resistant to Lepidoptera pests raises concerns regarding the conservation of animal and plant biodiversity. Demand for biofuels has increased the cultivation and importation of oilseed rape (Brassica napus L.), including transgenic lines. In environmental risk assessments (ERAs) for its potential future cultivation as well as for food and feed uses, the impact on wild Brassicaeae relatives and on non-target Lepidoptera should be assessed. Here we consider the potential exposure of butterflies as results of possible cultivation or naturalization of spilled seed in Sicily (Italy). Diurnal Lepidoptera, which are pollinat…
Aberrant splicing of the Drosophila melanogaster phenylalanine hydroxylase pre-mRNA caused by the insertion of a B104/roo transposable element in the…
1999
Abstract We report the insertion of the transposable element B104 in the Phenylalanine hydroxylase gene of the Drosophila mutant Henna-recessive 3 . Its presence alters the Phenylalanine hydroxylase splicing pattern, producing at least two aberrant mRNAs which contain part of the B104 sequence interrupting the coding region. This aberrant splicing is provoked by the use of a cryptic donor site encoded by the B104 3′ long terminal repeat in combination with either the gene intron 3 acceptor site or a novel acceptor site generated by the target duplication caused by transposition. One of them, referred as mRNA type 1, encodes a truncated protein that could be predictably non-functional. In mR…
Invasion of thehobo transposable element studied byin situ hybridization on polytene chromosomes ofDrosophila melanogaster
1994
The invasion kinetics of hobo transposable element in the Drosophila melanogaster genome was studied by in situ hybridization on the polytene chromosomes. Six independent lines of Drosophila melanogaster flies that had been previously transformed by microinjection of the pHFL1 plasmid containing a complete hobo element were followed over 50 generations. We observed that hobo elements were scattered on each of the chromosome arms, with more insertion sites on the 3R arm. The total number of insertion sites remains quite small, between four and six, at generation 52. On the 2R arm, a short inversion appeared once at generation 52. Most of the integration sites reported here were already descr…
The evolutionary genetics of the hobo transposable element in the Drosophila melanogaster complex.
1994
Hobo elements are a family of transposable elements found in Drosophila melanogaster and its three sibling species: D. simulans, D. mauritiana and D. sechellia. Studies in D. melanogaster have shown that hobo may be mobilized, and that the genetic effects of such mobilizations included the general features of hybrid dysgenesis: mutations, chromosomal rearrangements and gonadal dysgenis in F1 individuals. At the evolutionary level some hobo-hybridizing sequences have also been found in the other members of the melanogaster subgroup and in many members of the related montium subgroup. Surveys of older collected strains of D. melanogaster suggest that complete hobo elements were absent prior t…
Intraguild interactions between two egg parasitoids exploring host patches
2010
Intraguild interactions between two egg parasitoids, Trissolcus basalis (Hymenoptera: Scelionidae) and Ooencyrtus telenomicida (Hymenoptera: Encyrtidae), exploring egg masses of the Southern Green Stink Bug (SGSB) Nezara viridula (Heteroptera: Pentatomidae), were investigated in laboratory conditions by single, simultaneous and sequential host attack experiments. Mortality of N. viridula eggs was higher in simultaneous and sequential releases compared to single species releases. In simultaneous host exploitations, T. basalis females displayed an aggressive behavior against O. telenomicida females. The outcome of multiparasitism showed that interspecific larval competition was dominated by O…
Expression of phase-specific haemolymph polypeptides in a laboratory strain and field catches of Schistocerca gregaria.
2003
Uvarov's theory of locust phase polymorphism implies a differential phase-specific gene expression. It was the goal of the present investigation to provide data on the molecular level for this concept. We used the technique of 2D gel electrophoresis to generate haemolymph polypeptide maps from mature locust males. Under the given conditions we identified 238 polypeptide spots by their molecular weight and isoelectrical point. Isolated and crowded males from the Mainz strain, all originating from crowded ancesters, differed in 20 spots: three were solitary-specific and 17 crowded-specific. Field catches of solitary and gregarious S. gregaria in Mauritania revealed that those males showed the…
Analysis of involvement of the 3?-untranslated regions in regulating mRNA stability for vitellogenin, cyanoprotein ?, and cyanoprotein ? from the bea…
2002
The degradation of the 3'-untranslated regions (UTRs) of vitellogenin, cyanoprotein alpha, and cyanoprotein beta from the bean bug, Riptortus clavatus, was analyzed in vitro. The degradation pattern was similar for all three RNAs, with a high degradation rate in non-diapausing adult insects and no degradation in the fifth instar nymphs and in diapausing adults, and was not correlated with the expression levels of these three proteins. Proteins binding to the 3'-UTRs were detected in polysomal and cytosolic extracts. These factors, however, were present in all developmental stages. The abundance of the polysomal factor showed little variation, but the cytosolic factor was enriched in adult i…