Search results for "Insect Science"
showing 10 items of 1011 documents
Chemo-orientation responses in hymenopteran parasitoids induced by substrate-borne semiochemicals
2013
Hymenopteran parasitoids can utilize substrate-borne semiochemicals released by conspecifics or by their hosts, increasing the likelihood of successful mating and host location. According to the literature, two substrate-borne chemo-orientation patterns can occur: (1) biased random searching, a non-directional reaction toward the chemicals (kinesis), and (2) trailfollowing searching, a directional response toward the source emitting the chemical compounds (taxis). These two different strategies can be adopted by parasitoids to locate hosts and mates. In host location, random searching is induced by allelochemicals indirectly associated with the host, whereas trail-following behavior is indu…
Processing of RNAs of the Family Avsunviroidae in Chlamydomonas reinhardtii Chloroplasts
2007
ABSTRACT The family Avsunviroidae comprises four viroid species with the ability to form hammerhead ribozymes that mediate self-cleavage of the multimeric plus and minus strands resulting from replication in the chloroplast through a symmetric rolling-circle mechanism. Research on these RNAs is restricted by their host range, which is limited to the plants wherein they were initially identified and some closely related species. Here we report cleavage and ligation in transplastomic Chlamydomonas reinhardtii expressing plus- and minus-strand dimeric transcripts of representative members of the family Avsunviroidae . Despite the absence of viroid RNA-RNA transcription, the C. reinhardtii -bas…
Immune evasion proteins of murine cytomegalovirus preferentially affect cell surface display of recently generated peptide presentation complexes.
2009
CD8 T cells recognize infected cells by interaction of their T-cell receptor (TCR) with a cell surface presentation complex composed of a cognate antigenic peptide bound to a presenting allelic form of a major histocompatibility complex class I (MHC-I) glycoprotein (77, 85, 97, 98). The number of such “peptide receptors” per cell has been estimated to be on the order of 105 to 106 for each MHC-I allomorph (for a review, see reference 82). Viral antigenic peptides are generated within infected cells by proteolytic processing of viral proteins, usually in the proteasome, and associate with nascent MHC-I proteins in the endoplasmic reticulum (ER) before the peptide-MHC (pMHC) complexes travel …
Behaviour-modifying compounds for management of the red palm weevil (Rhynchophorus ferrugineusOliver)
2015
BACKGROUND Populations of red palm weevil (RPW), a severe pest of palms in Mediterranean countries, might be limited by semiochemical-based behaviour-disrupting methods. We evaluated the effects of electroantennogram (EAG)-active plant volatiles on the behaviour of RPWs from Italy and Israel. In field experiments, α-pinene, citronellol, geraniol, citral and 1-octen-3-ol were tested for their ability to disrupt attraction to pheromone–kairomone and molasses baited traps. Those that were found to be disruptive in the field were evaluated in a laboratory choice bioassay in individual cages for their effect on RPW female feeding and oviposition. RESULTS Field experiments showed reduced captures…
Substrate determinants for cleavage in cis and in trans by the hepatitis C virus NS3 proteinase
1995
Processing of the hepatitis C virus polyprotein is accomplished by a series of cotranslational and posttranslational cleavages mediated by host cell signalases and two virally encoded proteinases. Of these the NS3 proteinase is essential for processing at the NS3/4A, NS4A/4B, NS4B/5A, and NS5A/5B junctions. Processing between NS3 and NS4A occurs in cis, implying an intramolecular reaction mechanism, whereas cleavage at the other sites can also be mediated in trans. Sequence analysis of the amino termini of mature cleavage products and comparisons of amino acid residues around the scissile bonds of various hepatitis C virus isolates identified amino acid residues which might contribute to su…
American cockroach control assays in the municipal sewerage system of Valencia (Spain)
2013
ABSTRACT Several insecticides (including different active substances and formulations) were applied to sewer shafts to control Periplaneta americana (LINNAEUS, 1758) populations in Valencia (eastern Spain). Results show that the best products for cockroach control were the paints (with and without insecticide), which provided an optimal reduction of P. americana populations for up to three months (P < 0.001). Therefore, it is important to note that the reduction of cockroach populations as well as the persistence of the insecticide effect in sewers was similar in both types of paints. A product combining two pyrethroids (Tetramethrin and Alfacipermetrin) and piperonyl butoxide also gave …
Could Europe Apply a Suitable Control Method for the Small Hive Beetle (Coleoptera: Nitidulidae)?
2022
Abstract The European bee, Apis mellifera L. (Hymenoptera: Apidae), is a fundamental resource for the pollination of a great variety of botanical species used by humans for sustenance. Over the last few decades, bee colonies have become vulnerable to a new pest that has advanced beyond its native sub-Saharan territory: the small hive beetle, Aethina tumida Murray (Coleoptera: Nitidulidae). This currently presents a pressing problem in the United States and Australia, but it has also been recorded in Portugal and Italy and it is likely to spread in the rest of Europe too. This study represents a systematic review, based on EFSA guidelines, of the various control treatments for small hive bee…
Foragers of the stingless bee Plebeia droryana inform nestmates about the direction, but not the distance to food sources
2020
The tropical stingless bees have evolved intricate communication systems to recruit nestmates to food locations. Some species are able to accurately communicate the location of food, whereas others simply announce the presence of food in the environment. Plebeia droryana is a tiny Neotropical stingless bee that, until recently, was thought to use a solitary foraging strategy, that is without the use of a recruitment communication system. However, recent research has indicated that P. droryana might be able to recruit nestmates to specific food source locations. We tested this by studying whether foragers can guide nestmates in the direction and the distance of artificial feeders placed in t…
The fine structural organization of sternal glands of pseudergates and workers in termites (Isoptera): a comparative survey
2008
1873-5495 (Electronic) Comparative Study Journal Article; Thirty-nine species belonging to different families of termites are studied to give a comprehensive view of the evolution of the sternal glands. Several modifications occurring at cuticular and cytological levels are described in neuter castes. The outer epicuticle is always pierced by epicuticular pores. In advanced termites the epicuticular filaments greatly increase in number and length creating a thick layer. The pore canals gradually enlarge while the cuticle changes into a lattice structure lining an extracellular space in which the secretion is stored. Two classes of cells are present in basal termites (Mastotermitidae, Hodote…
Further Evidence that Papillomavirus Capsids Exist inTwo DistinctConformations
2003
ABSTRACT Cell surface heparan sulfate proteoglycans (HSPGs) serve as primary attachment receptors for human papillomaviruses (HPVs). To demonstrate that a biologically functional HPV-receptor interaction is restricted to a specific subset of HSPGs, we first explored the role of HSPG glucosaminoglycan side chain modifications. We demonstrate that HSPG O sulfation is essential for HPV binding and infection, whereas de-N-sulfated heparin interfered with VLP binding but not with HPV pseudoinfection. This points to differences in VLP-HSPG and pseudovirion-HSPG interactions. Interestingly, internalization kinetics of VLPs and pseudovirions, as measured by fluorescence-activated cell sorting analy…