Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “INSECTS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 307 records · Page 17Linked to original sources
PubMed1997

Structure of the insect head in ontogeny and phylogeny: a view from Drosophila.

Evolutionary, developmental and insect biologists are currently using a three-pronged approach to study the evolution and development of the insect head. First, genetic manipulation of the fruit fly Drosophila melanogaster has led to the identification of many genes, including the segmentation and homeotic genes, that are important for embryonic pattern formation and development. Second, a comparison of orthologous gene expression patterns in other insects reveals that these regulatory genes are deployed in similar, yet distinct, patterns in different insects. Third, comparisons of embryonic morphology with gene expression patterns suggest that in general these genes promote a common insect body plan, but that variations in gene expression can often be correlated to variations in morphology. Here, we present a detailed review of the development of the cephalic ectoderm of Drosophila and extrapolate to development of a generalized insect head. Our analysis of the variations among insect species, in both morphology and gene expression patterns, conducted within an evolutionary framework supported by traditional phylogenies and paleontology provides the basis for hypotheses about the genetic factors governing morphologic and developmental evolution.

Animals↗
PubMedDate not supplied

The use of decapitated insects to study lipid mobilization in adult Manduca sexta: effects of adipokinetic hormone and trehalose on fat body lipase activity.

In order to perform studies on lipid mobilization in adult M. sexta, it is necessary to overcome the effects of starvation and handling, which both provoke an increase in hemolymph lipid concentration. When trehalose was injected into intact insects, a 35% decrease in the content of the diacylglycerol (DG)-rich hemolymph lipoprotein, low density lipophorin (LDLp) was observed within 30 min, but the level of LDLp returned to control values after 1 h. Decapitated insects exhibited 60% reduction in LDLp concentration and the levels remained low for at least 24 h. In contrast to intact insects, injection of trehalose into decapitated animals did not alter the LDLp concentration. After decapitation, the response to adipokinetic hormone (AKH) and the ability of the fat body to release DG into the hemolymph was maintained for at least 24 h. In decapitated insects, 6 pmol of AKH-stimulated measurable lipid mobilization and a near maximum response was obtained with 100 pmol of the hormone. The action of trehalose and AKH on the fat body triacylglycerol (TG)-lipase activity in decapitated animals was studied. Fat body homogenates from trehalose-treated insects exhibited a TG-lipase activity 40% lower than the control insects. Activation of fat body triacylglycerol-lipase was observed after injection of AKH, with the extent of activation ranging between 97 and 380% ten min after AKH injection. A time course study showed that the activation of the fat body triacylglycerol lipase preceded the increase in hemolymph LDLp concentration, suggesting that activation of the lipase initiates lipid mobilization. It is concluded that decapitated insects injected with trehalose is a very useful system for investigating the hormonal regulation of lipid mobilization in adult M. sexta.

Animals↗
PubMed2004

Stinging and biting insect allergy: an Australian experience.

BACKGROUND: Stings and bites from various insects are responsible for many anaphylactic events. OBJECTIVE: To document the clinical features of specific forms of anaphylaxis and investigate clinical concerns regarding stinging and biting insect allergy. METHODS: All patients presenting for evaluation of adverse reactions to insect stings or bites between December 1980 and December 1997 had the clinical details of their reactions recorded and their reactions classified. RESULTS: The spectrum of clinical symptoms and signs is similar to that seen in anaphylaxis from other sources; stings on the head or neck are not more likely to cause life-threatening reactions than stings elsewhere on the body; a lesser reaction will not necessarily lead to a more serious reaction from a future sting; asthmatic patients do appear to have an increased risk of asthma as a feature of their anaphylactic response; anaphylaxis is usually confined to a particular insect species for the individual patient; patients who have had multiple stings at one time may have experienced true anaphylaxis and not a "toxic" response; and patients who have had anaphylaxis from other sources are at no greater risk than that of the general population of reacting similarly to insect stings or bites. CONCLUSIONS: Anaphylactic events from insect stings show the same clinical features as those from other sources. Systemic reactions seem confined to a specific insect species. Patients who experience RXN3 reactions from multiple stings at one time should undergo specific venom testing, because many have experienced true anaphylaxis and not a toxic response. Future consideration should be given to the role of beta-adrenergic antagonists and ACE inhibitors in patients with systemic reactions.

Adolescent↗
PubMed2003

Allergic reactions to insect stings and bites.

Insect stings are an important cause of anaphylaxis. Anaphylaxis can also occur from insect bites but is less common. Insect venoms contain several well-characterized allergens that can trigger anaphylactic reactions. Effective methods to diagnose insect sting allergy and assess risk of future sting reactions have been developed. Management strategies using insect avoidance measures, self-injectable epinephrine, and allergen immunotherapy are very effective in reducing insect-allergic patients' risk of reaction from future stings. Diagnostic and management strategies for patients allergic to insect bites are less developed.

Anaphylaxis↗
PubMed1997

Long-term association of tomato yellow leaf curl virus with its whitefly vector Bemisia tabaci: effect on the insect transmission capacity, longevity and fecundity.

The association between tomato yellow leaf curl geminivirus (TYLCV, Israeli isolate) and its insect vector, the whitefly Bemisia tabaci, was investigated. Insects that emerged during a 24 h period were caged with TYLCV-infected plants for a 48 h acquisition access period, then with egg-plants--a TYLCV non-host--for the rest of their lives. While TYLCV DNA was associated with the whiteflies during their entire adult life, the amount of capsid protein rapidly decreased and was not detectable in the insect after approximately 12 days of age. The ability of the infected whiteflies to transmit TYLCV to tomato test plants steadily decreased with age but did not disappear completely. Transmission by viruliferous insects decreased from 100% to 10-20% during their adult lifetime, compared with a decrease from 100% to 50% for non-viruliferous insects. The association of TYLCV with adult B. tabaci led to a reduction of 17-23% in their life expectancy compared with insects that had not acquired the virus, and to a 40-50% decrease in the mean number of eggs laid. These results suggest that TYLCV has some features reminiscent of an insect pathogen.

Animals↗
PubMed2005

Arabidopsis vegetative storage protein is an anti-insect acid phosphatase.

Indirect evidence previously suggested that Arabidopsis (Arabidopsis thaliana) vegetative storage protein (VSP) could play a role in defense against herbivorous insects. To test this hypothesis, other AtVSP-like sequences in Arabidopsis were identified through a Basic Local Alignment Search Tool search, and their transcriptional profiles were investigated. In response to methyl jasmonate application or phosphate starvation, AtVSP and AtVSP-like genes exhibited differential expression patterns, suggesting distinct roles played by each member. Arabidopsis VSP2 (AtVSP2), a gene induced by wounding, methyl jasmonate, insect feeding, and phosphate deprivation, was selected for bacterial expression and functional characterization. The recombinant protein exhibited a divalent cation-dependent phosphatase activity in the acid pH range. When incorporated into the diets of three coleopteran and dipteran insects that have acidic gut lumen, recombinant AtVSP2 significantly delayed development of the insects and increased their mortality. To further determine the biochemical basis of the anti-insect activity of the protein, the nucleophilic aspartic acid-119 residue at the conserved DXDXT signature motif was substituted by glutamic acid via site-directed mutagenesis. This single-amino acid alteration did not compromise the protein's secondary or tertiary structure, but resulted in complete loss of its acid phosphatase activity as well as its anti-insect activity. Collectively, we conclude that AtVSP2 is an anti-insect protein and that its defense function is correlated with its acid phosphatase activity.

Acetates↗
PubMed1964

OCCURRENCE OF COLIFORMS, FECAL COLIFORMS, AND STREPTOCOCCI ON VEGETATION AND INSECTS.

This study considers the sanitary significance of coliforms, fecal coliforms, and streptococci isolated from 152 species of plants and 40 samples of insects. These specimens were collected from various ecological environments and grouped into several categories. Results indicate that typical coliforms of the warm-blooded animal gut contribute a relatively small percentage of the organisms associated with vegetation (14.1%) and insects, (14.9%). A total of 1,203 coliform strains from vegetation and 1,084 coliform strains from insects were classified as to IMViC type and fecal coliform. No type was predominant in either the vegetation or insect groupings. The biochemical results for 646 streptococci from vegetation and 226 cultures from insects were reported. The predominant group, Streptococcus fecalis, as defined by Sherman criteria, constituted a majority of all strains from vegetation and insects. The "Completed Coliform Test" is recommended for the examination of plant and insect specimens to eliminate the many anaerobic and aerobic sporeforming bacteria that frequently produce false positive reactions by the "Confirmed Test" procedure. These findings support the current interpretation of the significance of the fecal coliform test for stream investigations or for surface water quality evaluations.

Animals↗
PubMed2000

Simulated insect defoliation on soybean: influence of row width.

An ongoing change in soybean production gaining popularity in the United States is a reduction in row spacing. Plant canopy closure is quicker and leaf area index is greater, thus yield is usually higher. Because yield response to insect defoliation is primarily a function of how defoliation causes changes in light interception, the possibility exists that the insect-injury-yield-loss relationship might differ among row widths. Soybean was grown in four states using similar methodologies. Insect defoliation was simulated by picking leaflets based on an insect defoliation model. Plant growth measurements were taken immediately following the end of defoliation. Numerous independent variables were measured or calculated, including percentage light interception, leaf area index, percentage defoliation, and leaf area per plot. Analyses of covariance were conducted on the resultant data to determine whether insect-injury-yield-loss relationships interact with row width. A significant interaction would indicate that the impact of the variables on yield was dependent on the row width, whereas a nonsignificant interaction would suggest that the relationship between the variables and yield is similar at all row widths. Few significant interactions were obtained, indicating that the impact of the variables on yield is similar across row widths. Because of the lack of significant interactions, the insect-injury-yield-loss relationships previously developed should be usable across varying row widths. Thus, treatment decisions based on light interception and leaf area indices, both considered more appropriated measures of insect injury, should be applicable for all row spacings.

Agriculture↗
PubMed2003

Stored-product insects associated with a retail pet store chain in Kansas.

The types and numbers of insect species associated with eight Kansas retail stores belonging to a pet store chain were surveyed during February to August 2001. Insects were monitored at 1-3-wk intervals using food- and pheromone-baited pitfall traps for beetles and pheromone-baited sticky traps for moths. Thirty traps of each type were placed within a store. Thirty insect species belonging to 20 families in four orders were recorded from the eight stores. The weevils, Sitophilus spp.; Indianmeal moth, Plodia interpunctella (Hübner); and merchant grain beetle, Oryzaephilus mercator (Fauvel), were the most common and abundant species in all stores, whereas the red-legged ham beetle, Necrobia rufipes (Degeer), and red flour beetle, Tribolium castaneum (Herbst), were abundant only in one store. The numbers of each insect species captured varied from store to store. In each of the stores, a total of 12-19 stored-product species were captured in traps, and seven of the eight stores had relatively high species diversity. With the exception of one store, the different types of insect species found among the remaining seven stores were essentially similar. The mean density of insects in infested bulk-stored and bagged pet food products removed from a store ranged from 65 to 656 adults/kg. The types and numbers of insect species captured in traps indicated that infestations were well established in the surveyed stores. Early detection and management of these infestations is critical for maintaining quality and integrity of food products sold in the pet stores.

Animal Feed↗
PubMed1993

Tendency to being bitten by insects among patients with eczema and with other dermatoses.

In order to ascertain whether patients with eczema are more prone to being bitten by insects than those with other dermatoses, data were collected by interview and questionnaire from 496 patients attending the outpatient department of a hospital in Sydney and a general dermatological practice in Geelong, Australia. Of the 93 patients with eczema 65% claimed they were prone to insect bite and that they were bitten in preference to other people when in a group, compared with 17% of the 403 patients with other chronic dermatoses. Similar proportions of both groups (approximately 50%) had used insect repellents. Excluding those with eczema 30% of the 149 patients with a family history of atopy claimed they were prone to being bitten by insects compared with 8% of the 254 patients without a family history of atopy. There was no difference in the prevalence of eczema or family history of atopy between men and women, but more women felt themselves to be susceptible to insect bites than men. There is evidence that patients with eczema and those with a family history of atopy are prone to being bitten by insects. Further confirmatory work, perhaps using volunteers and mosquitoes, is indicated. However, patients with severe eczema or a family history of atopy should take care when travelling to areas where disease-carrying insects are prevalent.

Adolescent↗
PubMed1996

[Insect stings. A prospective study of complications and injury mechanisms].

The aim of the study was to evaluate complications to insect stings, and to describe the circumstances in which the patients were stung. During a one year period (1.1.-31.12.1991) a total of 178 hospital and emergency room contacts due to insect stings were registered. All patients afterwards received a mailed questionnaire concerning insect stings. Nearly 3/4 of the patients were able to identify the stinging insect by use of an identification chart. One hundred and forty-five patients had mild symptoms, 33 patients had moderate symptoms and three presented severe symptoms with anaphylactic shock. Eleven percent of the patients required admission and another 21% were seen in out-patient clinics. More children than adults could after a physical examination be discharged from the hospital without treatment. More than 3/4 of the stings occurred in July, August and September and more than 3/4 were during the day and evening. We found that most of the insect stings were due to either wasps or bees and that no one stung by insects other than wasps or bees needed admission to hospital. We conclude that a major part of insect stings could be avoided by following ordinary precautions.

Adolescent↗
PubMed1986

Insect and meat eating among infant and adult baboons (Papio cynocephalus) of Mikumi National Park, Tanzania.

It has been suggested that baboon predation upon vertebrates may tend to peak in the dry season because insect food is then less available, and that males obtain animal nutrients primarily from vertebrates whereas other troop members obtain them primarily from invertebrates. The development of meat and insect eating by 22 male and 24 female infants studied for 25 months was compared with that of 18 male and 46 female adults studied for 37 months. Systematic sampling allowed quantitative comparisons between meat and insect eating, infants and adults, and males and females. Infants ate no meat, but their insect eating began early and increased steadily during the first year of life. In comparison with insect foods, meat was a minor ingredient of the adult's diet. Insect eating occurred less during dry than during rainy months, but meat eating was spread across the year. Reliable sex differences in insect eating did not occur. The findings were related to theories offered to explain the attractiveness of animal foods to primates and to the suggestion that a sex difference in predatory inclinations of hominid ancestors may have been a preadaptation underlying the eventual emergence of male hunting and female gathering.

Aging↗
PubMed2003

Conserved and convergent organization in the optic lobes of insects and isopods, with reference to other crustacean taxa.

The shared organization of three optic lobe neuropils-the lamina, medulla, and lobula-linked by chiasmata has been used to support arguments that insects and malacostracans are sister groups. However, in certain insects, the lobula is accompanied by a tectum-like fourth neuropil, the lobula plate, characterized by wide-field tangential neurons and linked to the medulla by uncrossed axons. The identification of a lobula plate in an isopod crustacean raises the question of whether the lobula plate of insects and isopods evolved convergently or are derived from a common ancestor. This question is here investigated by comparisons of insect and crustacean optic lobes. The basal branchiopod crustacean Triops has only two visual neuropils and no optic chiasma. This finding contrasts with the phyllocarid Nebalia pugettensis, a basal malacostracan whose lamina is linked by a chiasma to a medulla that is linked by a second chiasma to a retinotopic outswelling of the lateral protocerebrum, called the protolobula. In Nebalia, uncrossed axons from the medulla supply a minute fourth optic neuropil. Eumalacostracan crustaceans also possess two deep neuropils, one receiving crossed axons, the other uncrossed axons. However, in primitive insects, there is no separate fourth optic neuropil. Malacostracans and insects also differ in that the insect medulla comprises two nested neuropils separated by a layer of axons, called the Cuccati bundle. Comparisons suggest that neuroarchitectures of the lamina and medulla distal to the Cuccati bundle are equivalent to the eumalacostracan lamina and entire medulla. The occurrence of a second optic chiasma and protolobula are suggested to be synapomorphic for a malacostracan/insect clade.

Animals↗
PubMed2001

The molecular interactions of pyrethroid insecticides with insect and mammalian sodium channels.

Recent progress in the cloning of alpha (para) and beta (TipE) Na channel sub-units from Drosophila melanogaster (fruit fly) and Musca domestica (housefly) have facilitated functional expression studies of insect Na channels in Xenopus laevis oocytes, assayed by voltage clamp techniques. The effects of Type I and Type III pyrethroids on the biophysical properties of these channels are critically reviewed. Pyrethroid resistance mutations (termed kdr and super-kdr) that reduce the sensitivity of the insect Na channel to pyrethroids have been identified in a range of insect species. Some of these mutations (e.g. L1014F, M918T and T929I) have been incorporated into the para Na channel of Drosophila, either individually or in combination, to investigate their effects on the sensitivity of this channel to pyrethroids. The kdr mutation (L1014F) shifts the voltage dependence of both activation and steady-state inactivation by approximately 5 mV towards more positive potentials and facilitates Na channel inactivation. Incorporation of the super-kdr mutation (M918T) into the Drosophila Na channel also increases channel inactivation and causes a > 100-fold reduction in deltamethrin sensitivity. These effects are shared by T929I, an alternative mutation that confers super-kdr-like resistance. Parallel studies have been undertaken using the rat IIA Na channel to investigate the molecular basis for the low sensitivity of mammalian brain Na channels to pyrethroids. Rat IIA channels containing the mutation L1014F exhibit a shift in their mid-point potential for Na activation, but their overall sensitivity to permethrin remains similar to that of the wild-type rat channel (i.e. both are 1000-fold less sensitive than the wild-type insect channel). Mammalian neuronal Na channels have an isoleucine rather than a methionine at the position (874) corresponding to the super-kdr (M918) residue of the insect channel. Replacement of the isoleucine of the wild-type rat IIA Na channel with a methionine (I874M) increases deltamethrin sensitivity 100-fold. In this way, studies of wild-type and mutant Na channels of insects and mammals are providing a molecular understanding of kdr and super-kdr resistance in insects, and of the low pyrethroid sensitivity of most mammalian Na channels. They are also giving valuable insights into the binding sites for pyrethroids on these channels.

Animals↗
PubMed2004

Toxicity of pesticides to predatory mites and insects in apple-tree site under field conditions.

Various applications of active ingredients of six fungicides and three insecticides and acaricides at normally recommended dosages were tested on two predatory mite species (Amblyseius andersoni Chant and Anthoseius bakeri Garman) from the family Phytoseiidae and on two predatory insect species (Coccinella septempunctata L. Chrysopa perla L.) dominantly present on apple trees. Small differences were found between fungicide treatments. On the trees treated with six fungicide applications the predatory mites and insects survived and increased to a high level, often 20-40 phytoseiids per 100 leaves and 4-8 predatory insects per sample unit. Only the active ingredients tolylfluanid and myclobutanil resulted in lower densities of predatory mites (10-20 phytoseiids per 100 leaves). One application of insecticides-acaricides (active ingredients: clofentezine, phosalone) showed no toxic effect on predatory mites and insects. Two applications of phosalone and one of alpha-cypermethrine were slightly or moderately toxic. Two applications of alpha-cypermethrine and eight routine sprays of various insecticides-acaricides and fungicides were very toxic and resulted in the lowest maximum number of predatory mites and insects, approximately 0-10 phytoseiids per 100 leaves and 1-4 predatory insects per sample unit. The toxicity of pesticides to predatory mites and insects is based on the toxicity of the pesticide' active ingredient and the spray frequency. The active ingredients of fungicides and only one or two applications of insecticides and acaricides were not or slightly toxic and could be used in integrated pest management.

Animals↗
PubMed1994

An insect model for assessing mercury toxicity: effect of mercury on antioxidant enzyme activities of the housefly (Musca domestica) and the cabbage looper moth (Trichoplusia ni).

The effect of mercury as Hg2Cl2 and HgCl2 on the antioxidant enzyme levels and its toxicity was investigated in an insect model comprised of adult females of the common housefly, Musca domestica, and fourth-instar larvae of the cabbage looper moth, Trichoplusia ni. HgCl2 was found to be more toxic than Hg2Cl2 to both M. domestica and T. ni. The LC50s for M. domestica were 1.17% and 0.38% w/v concentration for Hg2Cl2 and HgCl2, respectively. For the more tolerant T. ni, the LC50S were 5.15% for Hg2Cl2 and 0.96% w/w concentration for HgCl2. The minimally acute LC5 dose of both oxidation states of Hg was approximately 0.005% for both insects (w/v for M. domestica and w/w for T. ni). At the LC5, both forms of Hg significantly induced the activity of superoxide dismutase in both insect species. Catalase was induced by both Hg2Cl2 and HgCl2 in M. domestica but was only induced by HgCl2 in T. ni. Glutathione-S-transferase, its peroxidase activity, and glutathione reductase activities were also significantly altered in most cases by Hg in both insects although the pattern of alternation was different between the two insects. It is evident that mercury induces oxidative stress in insects as it does in vertebrates. Our findings suggest that insects may serve as a valuable, non-mammalian model species to assess Hg-induced oxidative stress as a component of environmental toxicity.

Animals↗
PubMed2004

Multilevel selection and social evolution of insect societies.

How sterile, altruistic worker castes have evolved in social insects and how they are maintained have long been central topics in evolutionary biology. With the advance of kin selection theory, insect societies, in particular those of haplodiploid bees, ants, and wasps, have become highly suitable model systems for investigating the details of social evolution and recently also how within-group conflicts are resolved. Because insect societies typically do not consist of clones, conflicts among nestmates arise, for example about the partitioning of reproduction and the allocation of resources towards male and female sexuals. Variation in relatedness among group members therefore appears to have a profound influence on the social structure of groups. However, insect societies appear to be remarkably robust against such variation: division of labor and task allocation are often organized in more or less the same way in societies with high as in those with very low nestmate relatedness. To explain the discrepancy between predictions from kin structure and empirical data, it was suggested that constraints-such as the lack of power or information-prevent individuals from pursuing their own selfish interests. Applying a multilevel selection approach shows that these constraints are in fact group-level adaptation preventing or resolving intracolonial conflict. The mechanisms of conflict resolution in insect societies are similar to those at other levels in the biological hierarchy (e.g., in the genome or multicellular organisms): alignment of interests, fair lottery, and social control. Insect societies can thus be regarded as a level of selection with novelties that provide benefits beyond the scope of a solitary life. Therefore, relatedness is less important for the maintenance of insect societies, although it played a fundamental role in their evolution.

Animals↗
PubMed2003

Insect cell culture for industrial production of recombinant proteins.

Insect cells used in conjunction with the baculovirus expression vector system (BEVS) are gaining ground rapidly as a platform for recombinant protein production. Insect cells present several comparative advantages to mammalian cells, such as ease of culture, higher tolerance to osmolality and by-product concentration and higher expression levels when infected with a recombinant baculovirus. Here we review some of the recent developments in protein expression by insect cells and their potential application in large-scale culture. Our current knowledge of insect cell metabolism is summarised and emphasis is placed on elements useful in the rational design of serum-free media. The culture of insect cells in the absence of serum is reaching maturity, and promising serum substitutes (hydrolysates, new growth and production-enhancing factors) are being evaluated. Proteolysis is a problem of the BEVS system due to its lytic nature, and can, therefore, be a critical issue in insect cell bioprocessing. Several cell- or baculovirus proteases are involved in degradation events during protein production by insect cells. Methods for proteolysis control, the optimal inhibitors and culture and storage conditions which affect proteolysis are discussed. Finally, engineering issues related to high-density culture (new bioreactor types, gas exchange, feeding strategies) are addressed in view of their relevance to large-scale culture.

Animals↗