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PubMed2001

[Studies on transgenic tobacco plants expressing two kinds of insect resistant genes].

A synthetic Bt cry1Ac gene fussed with a secretary signal coding sequences at 5' end and a modified gna gene were used to construct a plant expression vector pBSGS1M+ and this vector was transferred into tobacco (Nicotiana tabacum L.) by Agrobacterium-mediated transformation method. Results of PCR, Southern blot and Slot blot analysis indicated that both the chimeric Bt cry1Ac and gna genes were integrated into the genomes of transformed plants. Western blot analysis indicated that at least the cry1Ac protein was produced in transgenic plants. Upon insect bioassay using cotton bollworm (Heliothis armigera Hubner), the mortality of insect larvae on 60% regenerated plants reached 100% in 5 days post infestation and the growth of the survived larvae was seriously inhibited; The results from insect bioassay with peach aphid (Myzus persicae) showed that the transgenic plants were aphid-resistant, evidenced by a 50%-60% reduction in aphid population density, even over 80% for some individual transgenic plants. These results reflect that the modification of the two insect resistant genes and construction of the expression vector are correct and could be valuable for later application in crop breeding for insect resistance.

Animals↗

PubMed1999

Insects at low pressure: applications to artificial ecosystems and implications for global windborne distribution.

Insects have a number of potential roles in closed-loop life support systems. In this study we examined the tolerance of a range of insect orders and life stages to drops in atmospheric pressure using a terrestrial atmosphere. We found that all insects studied could tolerate pressures down to 100 mb. No effects on insect respiration were noted down to 500 mb. Pressure toleration was not dependent on body volume. Our studies demonstrate that insects are compatible with plants in low-pressure artificial and closed-loop ecosystems. The results also have implications for arthropod colonization and global distribution on Earth.

Animals↗

PubMed2001

Soldier acceptability of a camouflage face paint combined with DEET insect repellent.

Under operational conditions, current doctrine requires separate application of the standard military insect repellent and camouflage face paint. Working with an industrial partner, Amon Re, Inc., we developed a combined camouflage face paint and insect repellent that offers excellent protection from arthropod disease vectors. We undertook a study to determine whether the new product was acceptable to soldiers under field conditions. A new formulation of camouflage face paint containing the insect repellent N,N-diethyl-3-methyl-benzamide (DEET) was tested for user acceptability during a joint-service, multinational, military field training exercise (Operation Cobra Gold 1999) in Thailand. Soldiers testing the camouflage face paint were members of one of three companies (A, B, and C) of 1st Battalion, 21st Infantry Regiment, 25th Infantry Division. Soldiers in A company (N = 98) received standard military camouflage face paint and the U.S. military's Extended Duration Topical Insect and Arthropod Repellent containing 33% DEET, soldiers in B company (N = 75) received a new formulation of camouflage face paint without DEET, and soldiers in C company (N = 88) received the new formulation of camouflage face paint containing 30% DEET. Every soldier who volunteered to participate completed the study and submitted responses to the questionnaire. The different treatments were evaluated while soldiers spent 4 days conducting simulated combat exercises in a hot, tropical environment in central Thailand. Soldiers were provided the test materials, given a briefing on the study, and completed an initial questionnaire on May 19, 1999. Soldiers completed a final questionnaire after they returned from the training exercise on May 24, 1999. Results of the study indicated that soldiers found the new formulation of 30% DEET camouflage face paint easier to apply (88% of respondents) and remove (77%) than the current standard issue camouflage face paint. Soldiers liked the new 30% DEET camouflage face paint formulation better (61%) and were more likely to recommend it (67%) than the old camouflage face paint formulation. Although the addition of DEET to the camouflage face paint occasionally caused minor irritation after application for a short period (less than 15 minutes), the new camouflage face paint formulation with 30% DEET was evaluated most often (72%) as either good or excellent. The new 30% DEET camouflage face paint formulation offers significant operational advantages: protection from disease-transmitting arthropods, elimination of the need to carry separate insect repellent and camouflage face paint, and reduction in the time required to apply repellent and camouflage face paint separately.

Adolescent↗

PubMed2002

[High expression of human angiogenesis inhibitor HIAF-1 in insect cells and biological activity].

BACKGROUND & OBJECTIVE: Human inhibiting angiogenesis factor-1(HIAF-1) expressed in E coli. shown the activity of inhibiting the angiogenesis of tumors. This study was designed to investigate the expression of HIAF-1 in insect cells and to elucidate its biological activity. METHODS: Recombinant baculovirus expression vector pAcuW51-HIAF-1 was constructed by recombinant DNA technique and cotransfected with linearized baculovirus DNA into sf9 cells to produce recombinant virus. The expression of recombinant HIAF-1 in insect cells infected by recombinant virus was detected by SDS-PAGE and Western blot. The recombinant protein was purified by affinity chromatography. In vitro endothelial proliferation inhibiting activity of recombinant HIAF-1 was examined by MTT method, its antitumor activity in vivo was studied in human esophageal cancer transplanted in nude mice. RESULTS: HIAF-1 was effectively expressed in insect cells as 26 KD fusing protein and its expression level was about 5-10% of insect cellular total soluble proteins. Recombinant HIAF-1 protein could inhibit endothelial cell proliferation in vitro with IC50 value of 3.1 micrograms/ml and inhibited remarkably growth of human esophageal cancer transplanted in nude mice. CONCLUSIONS: The recombinant HIAF-1 with better activity was successfully expressed in insect cells and establish a base for clinical application.

Angiogenesis Inhibitors↗

PubMed2002

Alternative lipid mobilization: the insect shuttle system.

Lipid mobilization in long-distance flying insects has revealed a novel concept for lipid transport in the circulatory system during exercise. Similar to energy generation for sustained locomotion in mammals, the work accomplished by non-stop flight activity is powered by oxidation of free fatty acids (FFA) derived from endogenous reserves of triacylglycerol. The transport form of the lipid, however, is diacylglycerol (DAG), which is delivered to the flight muscles associated with lipoproteins. In the insect system, the multifunctional lipoprotein, high-density lipophorin (HDLp) is loaded with DAG while additionally, multiple copies of the exchangeable apolipoprotein, apoLp-III, associate with the expanding particle. As a result, lipid-enriched low-density lipophorin (LDLp) is formed. At the flight muscles, LDLp-carried DAG is hydrolyzed and FFA are imported into the muscle cells for energy generation. The depletion of DAG from LDLp results in the recovery of both HDLp and apoLp-III, HDLp, identified which are reutilized for another cycle of DAG transport. A receptor for as a novel member of the vertebrate low-density lipoprotein (LDL) receptor family, does not seem to be involved in the lipophorin shuttle mechanism operative during flight activity. In addition, endocytosis of HDLp mediated by the insect receptor does not seem to follow the classical mammalian LDL pathway. Many structural elements of the lipid mobilization system in insects are similar to those in mammals. Domain structures of apoLp-I and apoLp-II, the non-exchangeable apolipoprotein components of HDLp, are related to apoB 100. ApoLp-III is a bundle of five amphipathic alpha-helices that binds to a lipid surface very similar to the four-helix bundle of the N-terminal domain of human apoE. Despite these similarities, the functioning of the insect lipoprotein in energy transport during flight activity is intriguingly different, since the TAG-rich mammalian lipoproteins play no role as a carrier of mobilized lipids during exercise and besides, these lipoproteins are not functioning as a reusable shuttle for lipid transport. On the other hand, the deviant behavior of similar molecules in a different biological system may provide a useful alternative model for studying the molecular basis of processes related to human disorders and disease.

Animals↗

PubMed1990

Large-scale propagation of insect cells.

Cultured insect cells have many uses in agriculture and medicine. They can be used in the diagnosis and isolation of a number of viruses infecting both animals and plants and for the laboratory study of these viruses. Large-volume culture of insect cells has been envisioned as a way of producing viruses for use in controlling insect pests and for the production of viral antigens for vaccine preparations. Recently they have become a potentially valuable way of producing a variety of proteins for human and veterinary medicine using the genetically engineered baculovirus expression vectors. The development of satisfactory cell lines and culture methods has proceeded at a slow, irregular pace, inhibited by the lack of knowledge of the physiology of the insect, its small size, and often by the lack of consistent, adequate support for the necessary developmental research. However, now that the basic culture systems are available, cell lines have been developed or can easily be developed for most needs. Suitable media are available and recent developments in refining existing media formations have resulted in low-cost media containing little protein to interfere with down-stream processing of cellular metabolites. Future developments are likely to further improve the media formulations and lower the cost. Technical problems relating to oxygen demand and cell fragility that inhibited the continued development of large-volume culture systems beyond the laboratory a few years ago now appear to be solved or at least are solvable. The successful culture of the Spodoptera cells in bioreactors of 40-liter capacity indicates that means of producing insect cells or their metabolic products on a commercial scale can be made economically feasible.

Animals↗

PubMedDate not supplied

[The role of microsporidia in the disturbance of the hormonal balance in the infected insects].

Since investigations of Fisher and Sanborn (1964), the most popular point of view on pathological alterations in the development of insects is the statement that microsporidians can produce and secrete the insect juvenile hormone in infected tissues. We suppose that the juvenilizing effect of microsoporidian infection may be a consequence of stress induced by the protozoan invasion. To our opinion, microsporidians can not be a source of juvenile hormone in parasitized insects because of several reasons. 1. The juvenilizing effect of infection may be explained by other reason, that is the stress effect of invasion. 2. Until now nobody can find juvenile hormone in microsporidians. 3. An increase of juvenile hormone titre either alters non-metabolic activity of fat body or alters it in a way that is not favorable for microsporidias. 4. Some effects of the microsporidian infection more resemble an action of ecdysone, but not juvenile hormone. Hypothesis of parasitic stress can explain this, while hypothesis of production JH by microsporidians can not. 5. An effect of invasion by parasites of other systematic groups onto the hormone balance is of the same type. But nobody thinks that other parasites can produce juvenile hormone. Nevertheless it is clear that a high titre of the juvenile hormone is favorable for the microsporidian infection in larvae, especially the last instars. The most descriptions of microsporidian infections are related with this age of insects. Juvenilizing effect of Nosema implantant in the work of Fisher and Sanborn (1964) may be easily explained by decreasing of JH-esterase activity. But in this case the decrease of JH-esterase activity after the implantation of infected tissue in a healthy insect should be explained. We suppose that this fact witness the existence of stress-factor produced by damaged cells of fat body that can enter the healthy cells of fat body and inhibit the activity of JH-esterases.

Animals↗

PubMed1992

Insect cells: adventitious agents.

The varied associations between insects and micro-organisms provides ample opportunity for the contamination of insect cell cultures. As with cell cultures from vertebrates, the addition of serum or serum products into cell culture media risks the introduction of mycoplasma and bovine viruses into cell cultures. Rarely do these organisms persist or multiply in insect cultures; however, there have been reports of the growth of Acholeplasmas introduced with fetal bovine serum. The contamination of cultures with plant or mammalian pathogens that are transmitted by insects is more common. The micro-organisms that are associated with insects, either as pathogens or commensals, frequently contaminate primary cell cultures and may also contaminate cell lines.

Animals↗

PubMed1992

The presence of uracil-DNA glycosylase in insects is dependent upon developmental complexity.

The metamorphosis of insects can, in a general way, be divided between those organisms that undergo pupation accompanied by cellular histolysis and those that gradually develop into adults without an intervening pupal stage of development. In the former case, the death of a cell population is an integral part of development that is tightly associated with massive DNA degradation during pupation. In that regard, it has been suggested that uracil-containing DNA acts as a target for the nucleolytic breakdown of DNA during histolysis in insects (Deutsch, W. A. (1987) Mutat. Res. 184, 209-215), thus placing into question how compatible the existence of uracil-DNA glycosylases would be for this form of developmental signal. As a result, we tested for the presence of a uracil-DNA glycosylase in insects representative of those having an intervening pupal stage of development and those that do not. We show here that a nonpupating insect contains a uracil-DNA glycosylase activity. Conversely, crude extracts of Drosophila melanogaster, as well as of three other insect populations that undergo pupation similar to that found in Drosophila, do not contain detectable levels of this DNA repair activity. Thus, there appears to be a consistent correlation between cellular destruction during development and the absence of a uracil-DNA glycosylase, which supports the possibility that uracil-containing DNA may play an important role in those cells targeted for death.

Animals↗

PubMedDate not supplied

A modified ultrarush insect venom immunotherapy protocol for children.

The prevalence of insect venom allergy in the European population is approximately 5%. Hymenoptera venom allergy is an important epidemiological problem. Ten to 40 deaths are reported annually in Germany. In contrast to conventional dose increase schedules lasting a minimum of 5 days, shorter protocols reduce the patient's stay in the hospital and provide an earlier protection toward stings. Clinical studies on ultrarush protocols have been published for adult patients, but very little data are currently available for children. Therefore, we investigated the safety and tolerability of a shortened insect venom immunotherapy (VIT) in children and adolescents. Forty-three children and adolescents (aged 4-18 years) with insect venom allergy were treated in this study. Five children were hyposensitized according to the ultrarush protocol with nine injections (as suggested by Brehler et al. (Safety of a two-day ultrarush insect VIT protocol in comparison with protocols of longer duration and involving a larger number of injections. J Allergy Clin Immunol 105:1231-1235,2000); 38 children received the modified ultrarush schedules with only eight subcutaneous injections. With both protocols the maintenance dose (100 microg) was achieved in 24 hours. Twenty-five patients (58.1%) showed no reaction after the injections. In 11 patients (25.6%), extensive erythema (>5 cm, maximum of 20 cm) was found at the injection site. Erythema and edema (>5 cm, maximum of 15 cm) were observed in seven patients (16.2%). The maintenance dose was well tolerated, with no systemic reaction in any patient. The modified ultrarush protocol for insect VIT used in this study showed very good tolerability and safety in children and adolescents. This dose regimen can increase compliance by shortening inpatient stay and reduces hospital costs.

Adolescent↗

PubMed2006

[Screen of media for insect cells (HzAm1) growth and its adaptation to low serum culture].

Insect cell-baculovirus system is a useful tool for both insecticidal virus production and the expression of medically useful foreign genes. Serum-free culture or low serum culture for insect cells is essential and significant. Media for the growth of insect cells HzAm1 from three kinds of commercial media TC-100,GRACE and IPL-41 with 10% serum were investigated and screened. The result shows that medium TC-100 is the most suitable medium for the growth of cells HzAm1. Adaptation of insect cells HzAm1 to cultures in medium TC-100 with serum reduction from 10% to 1% was carried out as cultures were supplemented with lactalbumin hydrolysate and yeastolate etc. Growth of insect cells HzAml in medium TC-100 with serum 1%, lactalbumin hydrolysate and yeastolate was well.

Adaptation, Physiological↗

PubMed2003

[Insect hypersensitivity in Iceland.].

In this article we review allergic reactions to stinging insects (hymenoptera) and biting insects (mosquitoes). We describe the first proven case of sensitization and anaphylaxis to hymenoptera in an Icelander. Yellow jackets, honeybees, paper wasps and hornets cause most sting reactions. The vespidae species were first seen in Iceland in 1973. Since that time, these insects have inhabited the island in ever increasing numbers. Symptoms range from local reactions to systemic anaphylaxis and even death. Accurate diagnosis is important as treatment with venom immunotherapy can prevent repeated reactions by at least 95%. Local reactions in children and adults and even widespread urticaria in children should not be treated with immunotherapy. Practical measures to avoid these insects and the characteristics of each species are discussed. Physicians and other health care workers must recognize the symptoms of insect sting allergy and know when to refer to an allergist for skin testing and possible immunotherapy.

English Abstract↗

PubMed2006

Local maladaptation in the soft scale insect Saissetia coffeae (Hemiptera: Coccidae).

Local adaptation has often been documented in herbivorous insects. The potential for local maladaptation in phytophagous insects, however, has not been widely considered. I performed a two-generation reciprocal cross-transplant experiment with the generalist soft scale insect Saissetia coffeae (Hemiptera: Coccidae) on two common species of host plants in rain forest habitat in Costa Rica. In this system, S. coffeae showed significant local maladaptation at the level of the host species. Lineages originally collected from Witheringia enjoyed a strong advantage over those collected from Lomariopsis when both sets of lineages were placed on Lomariopsis; however, when both sets of lineages were raised on Witheringia, their fitnesses were statistically indistinguishable. While some aspects of the biology of S. coffeae may impair its ability to adapt to local selection pressures, scale insects are often locally adapted on fine spatial scales, and local maladaptation is therefore especially surprising. Other documented cases of local maladaptation in parasites appear to be due to evolution on the part of the host. The possibility that hosts or natural enemies may place local genotypes at a disadvantage, producing a pattern of local maladaptation, is one that deserves more consideration in the context of plant-insect interactions.

Adaptation, Physiological↗

PubMed1987

Primary structure and comparative sequence analysis of an insect apolipoprotein. Apolipophorin-III from Manduca sexta.

The amino acid sequence of an insect apolipoprotein, apolipophorin-III from Manduca sexta, was determined by a combination of cDNA and protein sequencing. The mature hemolymph protein consists of 166 amino acids. The cDNA also encodes for an amino-terminal extension of 23 amino acids which is not represented in the mature hemolymph protein. The existence of a precursor protein was confirmed by in vitro translation of fat body mRNA. Computer-assisted comparative sequence analysis revealed the following points: 1) the protein is composed of tandemly repeating tetradecapeptide units with a high potential for forming amphiphilic helical structures. Compared to mammalian apolipoproteins the repeat units in the insect apolipoprotein show considerable length variability; 2) the sequence has a striking resemblance to several human apolipoproteins including apoE, AIV, AI, and CI. However, the homology seems to be entirely functional since, although the insect and mammalian apoproteins contain very similar types of amino acid residues, the actual degree of sequence identity is quite low. Whether the mammalian and insect apoproteins are derived from a common ancestral amphiphilic helix forming, lipid-binding protein, or arose by convergent evolution can not be determined at present. This represents the first complete amino acid sequence for an insect apolipoprotein.

Algorithms↗

PubMed1984

[Regularities of the content and organization of pyrimidine oligonucleotide sequences in insect DNA].

Certain regularities in content and organization of pyrimidine oligonucleotide sequences of DNA from 15 insect species belonging to 4 orders were studied. The degree of nucleotide clusterization in insect DNA was found to be species-specific, being the highest in Hymenoptera and lowest in Lepidoptera; the Blattodea and Coleoptera occupy an intermediate position by this index between them. The changes in the DNA cluster structure during the evolution of insect species are not of vector type; the degree of clusterization of DNA nucleotide is either increased (Hymenoptera) or decreased (Lepidoptera as compared with Blattodea). In the DNA oligonucleotide fractions containing both pyrimidine nucleotides the percentage content of thymidyl nucleotides is much higher than that of cytidyl nucleotides, the thymine content being increased with the lengthening of oligopyrimidine clusters. The insect species with a higher degree of clusterization of DNA pyrimidine nucleotides contain more thymidyl nucleotide residues. These results agree well with the hypothesis suggesting that during the evolution of large taxons the accumulation of long pyrimidine sequences in animal DNA is accompanied by an increase of thymidyl nucleotide content in them. This can largely be due to the increase of matrix resistance during the evolution and is biologically significant for animals of any taxons, including insects.

Animals↗

PubMed1993

Insect defensin, an inducible antibacterial peptide, forms voltage-dependent channels in Micrococcus luteus.

Insect defensins are cationic, cysteine-rich peptides (approximately 4 kDa) that appear after bacterial challenge or injury in the hemolymph of insects belonging to a large variety of orders. These peptides possess anti-Gram-positive activity and participate in the potent antibacterial defense reactions of insects. Using recombinant insect defensin and the strain Micrococcus luteus as a test organism, we have investigated the mode of action of this peptide. We show that defensin disrupts the permeability barrier of the cytoplasmic membrane of M. luteus, resulting in a loss of cytoplasmic potassium, a partial depolarization of the inner membrane, a decrease in cytoplasmic ATP, and an inhibition of respiration. Potassium loss is inhibited below the order-disorder transition of the lipid hydrocarbon chains. It is also inhibited by divalent cations and by a decrease in the membrane potential below a threshold of 110 mV. We propose that these permeability changes reflect the formation of channels in the cytoplasmic membrane by defensin oligomers. This proposal is supported by patch-clamp experiments that show that insect defensins form channels in giant liposomes.

Adenosine Triphosphate↗

PubMed1994

Molecular characteristics of four new depressant insect neurotoxins purified from venom of Buthus martensi Karsch by HPLC.

Suitable pattern and high yield were obtained when the reverse-phase performance liquid chromatography (RP-HPLC) was used to separate neurotoxins from venom of Chinese scorpion Buthus martensi Karsch. Using this technique, the venom was first separated to two main regions. The toxicity tests show that the insect-selective neurotoxical components are concentrated in the latter region, from which five insect-selective neurotoxins designated by BmK IT1-IT5 were obtained. According to the results of the toxicity test as well as the amino acid composition and N-terminal analyses, BmK IT1 is the excitatory insect neurotoxin as reported in a previous paper, and the others are the newly found depressant insect-selective neurotoxins. The molecules of all the four toxins are single-chain minipeptides of about 60 amino acids. Their isoelectric points (pI) are between 8.3 and 8.5. The fact that BmK IT2 loses completely its insect toxicity after being modified by fluorochrome shows that the positive charges on the molecular surface of this kind of toxins are important to maintaining the bioactivity of the molecules.

Amino Acid Sequence↗

PubMed1997

The use of insects to determine time of decapitation: a case-study from British Columbia.

A case is presented in which insects were used to determine time of decapitation. A severed human head was located on 28 June in a ditch on Vancouver Island, British Columbia, Canada. The victim had been missing since 17 June. Prepupal Calliphora vomitoria (L.) were found at the cut surface of the neck and no evidence of insect feeding was observed at any of the natural orifices; the eyes were intact. Meteorological and insect developmental data indicated that the insects had been oviposited on or before 20 June. The lack of feeding at the orifices, together with the evidence of feeding and presence of insects at the cut surface of the neck indicated that the eggs had been laid after decapitation. Therefore, decapitation had occurred on or before 20 June. This was consistent with later police evidence.

Adult↗