Dipteran Insects Research Articles

Pareidolia in scientific zoological illustrations by example of dipteran insects

Article considers pareidolia in scientific zoological illustrations from the point of view of depicted object (model) and in terms of perception of the outline drawings (for example, details of dipteral morphology). Contour (linear, binary) images, due to their properties (lack of information about the color, volume, perspective relationships of depicted object), make it possible to emphasize and strengthen pareidolia already existing in the material — science artists get space for artistic maneuver and produce affective imagery, despite the stringent requirements for accuracy of depicted contours (considered art history parallels and examples of collaboration of artists and scientists). Author suggested hypothesis about the use of images for pareidolic quasi-collage composing of imaginary characters — iconozoes. Historical and evolutionary antiquity of pareidolia emphasized, parallels with cultural entomology and ethnoentomology drawn (ritual masks, polyeiconic objects of ancient art).

Bacillus thuringiensis Cyt2Aa2 toxin disrupts cell membranes by forming large protein aggregates.

Bacillus thuringiensis (Bt) Cyt2Aa2 showed toxicity against Dipteran insect larvae and invitro lysis activity on several cells. It has potential applications in the biological control of insect larvae. Although pore-forming and/or detergent-like mechanisms were proposed, the mechanism underlying cytolytic activity remains unclear. Analysis of the haemolytic activity of Cyt2Aa2 with osmotic stabilizers revealed partial toxin inhibition, suggesting a distinctive mechanism from the putative pore formation model. Membrane permeability was studied using fluorescent dye entrapped in large unilamellar vesicles (LUVs) at various protein/lipid molar ratios. Binding of Cyt2Aa2 monomer to the lipid membrane did not disturb membrane integrity until the critical protein/lipid molar ratio was reached, when Cyt2Aa2 complexes and cytolytic activity were detected. The complexes are large aggregates that appeared as a ladder when separated by agarose gel electrophoresis. Interaction of Cyt2Aa2 with Aedes albopictus cells was investigated by confocal microscopy and total internal reflection fluorescent microscopy (TIRF). The results showed that Cyt2Aa2 binds on the cell membrane at an early stage without cell membrane disruption. Protein aggregation on the cell membrane was detected later which coincided with cell swelling. Cyt2Aa2 aggregations on supported lipid bilayers (SLBs) were visualized by AFM. The AFM topographic images revealed Cyt2Aa2 aggregates on the lipid bilayer at low protein concentration and subsequently disrupts the lipid bilayer by forming a lesion as the protein concentration increased. These results supported the mechanism whereby Cyt2Aa2 binds and aggregates on the lipid membrane leading to the formation of non-specific hole and disruption of the cell membrane.

Rapid mapping of compound eye visual sampling parameters with FACETS, a highly automated wide-field goniometer.

A highly automated goniometer instrument (called FACETS) has been developed to facilitate rapid mapping of compound eye parameters for investigating regional visual field specializations. The instrument demonstrates the feasibility of analyzing the complete field of view of an insect eye in a fraction of the time required if using non-motorized, non-computerized methods. Faster eye mapping makes it practical for the first time to employ sample sizes appropriate for testing hypotheses about the visual significance of interspecific differences in regional specializations. Example maps of facet sizes are presented from four dipteran insects representing the Asilidae, Calliphoridae, and Stratiomyidae. These maps provide the first quantitative documentation of the frontal enlarged-facet zones (EFZs) that typify asilid eyes, which, together with the EFZs in male Calliphoridae, are likely to be correlated with high-spatial-resolution acute zones. The presence of EFZs contrasts sharply with the almost homogeneous distribution of facet sizes in the stratiomyid. Moreover, the shapes of EFZs differ among species, suggesting functional specializations that may reflect differences in visual ecology. Surveys of this nature can help identify species that should be targeted for additional studies, which will elucidate fundamental principles and constraints that govern visual field specializations and their evolution.

IDENTIFICATION AND EXPRESSION ANALYSIS OF TWO 14-3-3 PROTEINS IN THE MOSQUITO Aedes aegypti, AN IMPORTANT ARBOVIRUSES VECTOR.

The 14-3-3 proteins are evolutionarily conserved acidic proteins that form a family with several isoforms in many cell types of plants and animals. In invertebrates, including dipteran and lepidopteran insects, only two isoforms have been reported. 14-3-3 proteins are scaffold molecules that form homo- or heterodimeric complexes, acting as molecular adaptors mediating phosphorylation-dependent interactions with signaling molecules involved in immunity, cell differentiation, cell cycle, proliferation, apoptosis, and cancer. Here, we describe the presence of two isoforms of 14-3-3 in the mosquito Aedes aegypti, the main vector of dengue, yellow fever, chikungunya, and zika viruses. Both isoforms have the conserved characteristics of the family: two protein signatures (PS1 and PS2), an annexin domain, three serine residues, targets for phosphorylation (positions 58, 184, and 233), necessary for their function, and nine alpha helix-forming segments. By sequence alignment and phylogenetic analysis, we found that the molecules correspond to Ɛ and ζ isoforms (Aeae14-3-3ε and Aeae14-3-3ζ). The messengers and protein products were present in all stages of the mosquito life cycle and all the tissues analyzed, with a small predominance of Aeae14-3-3ζ except in the midgut and ovaries of adult females. The 14-3-3 proteins in female midgut epithelial cells were located in the cytoplasm. Our results may provide insights to further investigate the functions of these proteins in mosquitoes.

Identification of AaCASPS7, an effector caspase in Aedes albopictus

Aedes albopictus mosquito is a vector of various arboviruses and is becoming a significant threat to public health due to its rapid global expansion. Several reports suggest that apoptosis could be a factor limiting arbovirus infection in mosquitoes. Thus, it is significant to identify apoptosis pathway and study the correlation between apoptosis and virus infection in mosquitoes. Apoptosis is a type of programmed cell death that plays a vital role in immunity, development, and tissue homeostasis. Caspases are a family of conserved proteases playing important roles in apoptosis. In this study, we identified Aedes albopictus AaCASPS7, a caspase shared high identity with dipteran insect drICE orthologs. Phylogenetic analysis showed the closest relative of AaCASPS7 was Aedes aegypti AeCASPS7. AaCASPS7 displayed several features that were typical of an effector caspase and showed significant activity to effector caspase substrates. Aacasps7 transcripts were expressed ubiquitously in developmental and adult stages in Aedes albopictus mosquitoes. Transient expression of AaCASPS7 induced caspase-dependent apoptosis in C6/36 cells. Taken together the above data, this study identified a novel caspase, AaCASPS7, which might function as an apoptotic caspase. Further study the function of AaCASPS7 would facilitate better understanding the apoptotic mechanism in Aedes albopictus mosquito.

Dipteran Halteres: Perspectives on Function and Integration for a Unique Sensory Organ.

The halteres of dipteran insects (true flies) are essential mechanosensory organs for flight. These are modified hindwings with several arrays of sensory cells at their base, and they are one of the characteristic features of flies. Mechanosensory information from the halteres is sent with low latency to wing-steering and head movement motoneurons, allowing direct control of body position and gaze. Analyses of the structure and dynamics of halteres indicate that they experience very small aerodynamic forces but significant inertial forces, including Coriolis forces associated with body rotations. The sensory cells at the base of the haltere detect these forces and allow the fly to correct for perturbations during flight, but new evidence suggests that this may not be their only role. This review will examine our current understanding of how these organs move, encode forces, and transmit information about these forces to the nervous system to guide behavior.

The Strica Homolog AaCASPS16 Is Involved in Apoptosis in the Yellow Fever Vector, Aedes albopictus.

Caspases are a family of cysteine proteases playing essential roles during apoptosis. Seven caspases identified in Drosophila were Dronc, Dredd, Strica, Dcp-1, Decay, Drice and Damm. Among them, Strica is an insect-specific caspase containing a long serine- and threonine- rich prodomain, of which function is not yet well studied. Here we identified a homolog of strica from Aedes albopictus, named as Aacasps16. Aacasps16 encoded a protein containing a putative serine- and threonine-rich prodomain and a well conserved caspase catalytic domain. AaCASPS16 shared high identity with dipteran insects Strica homologs. Alignment showed that the closest relative of AaCASPS16 was Aedes aegypti AeCASPS16. The expression profiles of Aacasps16 during developmental and adult stages were analyzed. Purified recombinant AaCASPS16 exhibited the highest caspase activity to WEHD, which is the substrate preferred by human caspase-9. AaCASPS16 induced apoptosis when over-expressed in C6/36 cells. AaCASPS16 was processed during apoptosis induced by actinomycin D and ultraviolet irradiation treatment, whereas partial silencing of Aacasps16 reduced actinomycin D- and ultraviolet irradiation-triggered apoptosis in C6/36 cells. Taken together, our study identified AaCASPS16 as a novel apoptotic caspase in Aedes albopictus.

A simple method for immobilising small dipteran insects and its validation for Aedes aegypti

A simple method for immobilising small dipteran insects and its validation for <i><scp>A</scp>edes aegypti</i>

Identification of Aadnr1, a novel gene related to innate immunity and apoptosis in Aedes albopictus

Innate immunity and apoptosis play critical roles in defending pathogens in insects. In Drosophila, Dnr1 was reported as a negative regulator of apoptosis and immune deficiency (Imd) pathway which belongs to innate immunity. Aedes albopictus is an important kind of arbovirus vector and becoming a significant threat to public health due to its rapid global expansion. Here we identified an ortholog of dnr1 from A. albopictus, named as Aadnr1. Aadnr1 encoded a putative protein containing an N-terminal FERM domain and a C-terminal RING domain. AaDnr1 shared high identity with dipteran insects Dnr1 orthologs. Phylogenetic analyses showed that the closest relative of AaDnr1 was Aedes aegypti Dnr1. Real-time PCR proved that Aadnr1 mRNA was expressed ubiquitously during developmental and adult stages. Transcriptional levels of Aadnr1 were decreased drastically in C6/36 cells underwent apoptosis induced by Actinomycin D (Act D) treatment. Partial silence of Aadnr1 enhanced Act D-induced caspase activity. When challenged by heat-inactivated E. coli, transcriptional level of Aadnr1 was also decreased dramatically in C6/36 cells. While when C6/36 cells were infected with Sindbis virus TE/GFP, transcriptional level of Aadnr1 was reduced and recovered repeatedly, with an overall decreasing trend. It was also shown in this study that similar to Drosophila Dnr1, RING domain destabilized AaDnr1 protein. Taken together, the study identified an innate immunity and apoptosis related gene Aadnr1 in A. albopictus.

Garlic: A potential source of pharmaceuticals and pesticides: A review

Garlic (Allium sativum) holds a unique therapeutic potential as it inhibits invasion of carcinoma, provides cardiovascular protection, lowering of cholesterol, blood pressure, anti-platelet activities, and thromboxane formation. It provides protection against atherosclerosis and associated disorders and helps to decrease serum levels of glucose, insulin, triglycerides, and uric acid, as well as insulin resistance, and reduces cytokine levels. It shows hypolipidemic, anti-platelet, and procirculatory effects, and antimutagenic and antiproliferative properties. It prevents cold and flu symptoms through immune enhancement and exhibits anticancer and chemopreventive activities. The main active component of garlic is alliin (S-allyl cysteine sulfoxide), a potent antioxidant which shows cardioprotective and neuroprotective actions. Diallyl trisulfide, major garlic derivatives, could inhibit the cell proliferation by triggering either cell cycle arrest or apoptosis in a variety of cancer cells. Organosulfur compounds from garlic inhibit the growth of transplanted as well as spontaneous cancers in preclinical animal models without any adverse side effects. Garlic is a good source of anti-invasive, antioxidant, anti-inflammatory, immunomodulatory, chemopreventive, hepatoprotective, antimicrobial, apoptotic, cardioprotective, antidiabetic agents and shows insecticidal effects against lepidopteran, coleopteran, dipteran and homopteran insect pests. Hence, its constituents could be used to develop alternatives to conventional insecticides for control of serious fruit and vegetable pests. Garlic herbal preparations can reduce non-target exposure to hazardous insecticides and curb resistance development in insects. No doubt garlic based different ailments and concoctions can be used to alleviate a variety of health problems. Its various supplements contain a different concentration of organosulfur compounds are available commercially in market

Dnmt2 is the most evolutionary conserved and enigmatic cytosine DNA methyltransferase in eukaryotes

Dnmt2 is the most strongly conserved cytosine DNA methyltransferase in eukaryotes. It has been found in all organisms possessing methyltransferases of the Dnmt1 and Dnmt3 families, whereas in many others Dnmt2 is the sole cytosine DNA methyltransferase. The Dnmt2 molecule contains all conserved motifs of cytosine DNA methyltransferases. It forms 3D complexes with DNA very similar to those of bacterial DNA methyltransferases and performs cytosine methylation by a catalytic mechanism common to all cytosine DNA methyltransferases. Catalytic activity of the purified Dnmt2 with DNA substrates is very low and could hardly be detected in direct biochemical assays. Dnmt2 is the sole cytosine DNA methyltransferase in Drosophila and other dipteran insects. Its overexpression as a transgene leads to DNA hypermethylation in all sequence contexts and to an extended life span. On the contrary, a null-mutation of the Dnmt2 gene leads to a diminished life span, though no evident anomalies in development are observed. Dnmt2 is also the sole cytosine DNA methyltransferase in several protists. Similar to Drosophila these protists have a very low level of DNA methylation. Some limited genome compartments, such as transposable sequences, are probably the methylation targets in these organisms. Dnmt2 does not participate in genome methylation in mammals, but seems to be an RNA methyltransferase modifying the 38th cytosine residue in anticodon loop of certain tRNAs. This modification enhances stability of tRNAs, especially in stressful conditions. Dnmt2 is the only enzyme known to perform RNA methylation by a catalytic mechanism characteristic of DNA methyltransferases. The Dnmt2 activity has been shown in mice to be necessary for paramutation establishment, though the precise mechanisms of its participation in this form of epigenetic heredity are unknown. It seems likely, that either of the two Dnmt2 activities could become a predominant one during the evolution of different species. The high level of the Dnmt2 evolutionary conservation proves its activity to have a significant adaptive value in natural environment.

An Insect Proton Channel

Voltage-gated proton channels have been identified in a wide range of eukaryotes. The channel is an important component of the cellular proton extrusion machinery and is essential for charge compensation during the respiratory burst of phagocytes. Especially in the animal kingdom voltage gated proton channels can be found consistently. However, most insect genomes analyzed so far seems to be deprived of voltage-gated proton channels. Therefore, it has been proposed that insects do not possess voltage-gated proton channels, although until recently mainly dipteran insect genomes were sequenced. Despite this long standing dogma, here we report the discovery of voltage-gated proton channels in insects. We have performed a comprehensive search in insect TSA data bases and found putative Hv homologs in basal insects and various polyneopteran species. As a prototype insect Hv channel, the proton channel of the zygentoma Nicoletia phytophila (NpHV1) is composed of 239 amino acids with protein identity of 33% to the human proton channel hHV1. Patch clamp measurements in a heterologous expression system showed proton selectivity, pH dependent and voltage dependent gating. Interestingly, NpHv1 shows a slightly enhanced pH dependent gating compared to the human channel. Mutations at position 66 (Asp66), the presumed selectivity filter, lead to a loss of proton-selective conduction, confirming the importance of the aspartate in the first transmembrane segment in all voltage-gated proton channels.

Gap Gene Regulatory Dynamics Evolve along a Genotype Network.

Developmental gene networks implement the dynamic regulatory mechanisms that pattern and shape the organism. Over evolutionary time, the wiring of these networks changes, yet the patterning outcome is often preserved, a phenomenon known as “system drift.” System drift is illustrated by the gap gene network—involved in segmental patterning—in dipteran insects. In the classic model organism Drosophila melanogaster and the nonmodel scuttle fly Megaselia abdita, early activation and placement of gap gene expression domains show significant quantitative differences, yet the final patterning output of the system is essentially identical in both species. In this detailed modeling analysis of system drift, we use gene circuits which are fit to quantitative gap gene expression data in M. abdita and compare them with an equivalent set of models from D. melanogaster. The results of this comparative analysis show precisely how compensatory regulatory mechanisms achieve equivalent final patterns in both species. We discuss the larger implications of the work in terms of “genotype networks” and the ways in which the structure of regulatory networks can influence patterns of evolutionary change (evolvability).

日本の水生動物に寄生するミズダニ類（Acari:Hydrachnidiae and Stygothrombiae）

Water mites are known to live in aquatic habitats and larval or post-larval stages are temporarily or habitually parasitic on the body surface of aquatic animals in their life cycle. Associations on the species level have been documented for 25 species, 14 genera, and 11 families in Hydrachnidiae with 44 species, 36 genera, 24 families, and six orders in Arthropoda and seven species, four genera, two families, and two orders in Mollusca. Host-parasite correspondences between mite and host taxa were observed. A large number of water-mite genera containing Hydrodroma, Hydryphantes, Protzia, Thyas, Lebertia, Sperchon, Hygrobates, Atractides, Piona, Pionopsis, Neumania, Arrenurus, and Stygomomonia were parasitic on dipteran insects. Protzia and Stygomomonia were also parasitic on trichopteran hosts, and Hydryphantes, Eylais, and Hydrachna were parasitic on coleopteran hosts. Aquatic hemipterans were infested with Hydrachna and Lebertia. Lebertia, Piona, and Arrenurus also lived on odonates. On the other hand, plecopterans were exclusively infested with Wandesia, Partnunia, and Stygothrombium. Unionicola was uniquely parasitic on freshwater gastropods and bivalves.

Effects of agroecosystems on insect and insectivorous bat activity:a preliminary finding based on light trap and mist net captures

This study investigated the effects of agroecosystems on predator-prey activities. Therefore, bats and insects were sampled from various agroecosystems using mist netting and light trapping techniques. A generalized linear model was then employed to analyze some biotic and abiotic factors' effects on insect and insectivorous bat activities. The results indicate that agroecosystems and lunar cycles have significant effects on insect activity (Lepidopteran, Dipteran, and total insect activity) and insectivorous bat activity (Hipposideros jonesi, Hipposideros aff. ruber, and overall insectivorous bat activity). Generally, inorganic farms recorded the least insect and insectivorous bat activity, while fallow lands and teak plantations obtained higher levels of activity for all analyses. In addition, our findings suggest that activity levels of both insects and insectivorous bats follow a lunar cycle. While the effect of temperature (overall insect activity, P = 0.7474; overall insectivorous bat activity, P = 0.7310) was not significant, wind speed (P = 0.0102) had a significantly negative relationship with total insectivorous bat activity. Additionally, there was a positive correlation between total insect and insectivorous bat activity (P = 0.0190). This study emphasizes the negative effects of agricultural intensification on insectivorous bat and insect activities, and thus indicates the importance of fallow lands and woodlots for conservation.

Exploring the immune signalling pathway-related genes of the cattle tick Rhipicephalus microplus: From molecular characterization to transcriptional profile upon microbial challenge

In dipteran insects, invading pathogens are selectively recognized by four major pathways, namely Toll, IMD, JNK, and JAK/STAT, and trigger the activation of several immune effectors. Although substantial advances have been made in understanding the immunity of model insects such as Drosophila melanogaster, knowledge on the activation of immune responses in other arthropods such as ticks remains limited. Herein, we have deepened our understanding of the intracellular signalling pathways likely to be involved in tick immunity by combining a large-scale in silico approach with high-throughput gene expression analysis. Data from in silico analysis revealed that although both the Toll and JAK/STAT signalling pathways are evolutionarily conserved across arthropods, ticks lack central components of the D. melanogaster IMD pathway. Moreover, we show that tick immune signalling-associated genes are constitutively transcribed in BME26 cells (a cell lineage derived from embryos of the cattle tick Rhipicephalus microplus) and exhibit different transcriptional patterns in response to microbial challenge. Interestingly, Anaplasma marginale, a pathogen that is naturally transmitted by R. microplus, causes downregulation of immune-related genes, suggesting that this pathogen may manipulate the tick immune system, favouring its survival and vector colonization.

Entomofaunal Succession Patterns on Burnt and Unburnt Rabbit Carrion.

The influence of burning on the decomposition of rabbit carcasses and on insect succession was investigated in three different habitats (agricultural, desert, and urban) in order to provide data for estimating the postmortem interval (PMI). Each site had six carcasses divided into two groups of three rabbits, with the carcasses in one group being partially burned, while the others were not burned. Carrion reached the dry stage within 5 d in the desert and urban habitats and 13 d in the agricultural habitat. The unburnt and burnt carcasses also decomposed at a similar rate in the three study habitats. Adult dipteran and coleopteran insects were collected daily. A total of 24 species and 2,381 specimens were collected; of these, 732 specimens from 21 species were taken from the partially burnt carcasses and 1,649 specimens from 21 species from the unburnt carcasses. There were significantly distinct insect communities between the agricultural habitat and the desert and urban habitats. There were also significant differences in the insect communities between the decay stage and other stages, with fresh and dry stages recording the lowest number of insects. There were some species which only presented themselves during the decay stage of decomposition, namely, Platypalpus sp., Desmometopa varipalpis Malloch, Atherigona orientalis (Schiner), Atherigona yorki Deeming, Musca sorbens Weidemann, and Onthophagus nitidulus Klug. In addition, there were significant distinctions in the insect communities between unburnt carcasses and burnt carcasses. The presence of these distinctions means that it is possible to estimate the PMI from partially burnt rabbit carcasses.

Hemipteran and dipteran pests: Effectors and plant host immune regulators.

Hemipteran and dipteran insects have behavioral, cellular and chemical strategies for evading or coping with the host plant defenses making these insects particularly destructive pests worldwide. A critical component of a host plant's defense to herbivory is innate immunity. Here we review the status of our understanding of the receptors that contribute to perception of hemipteran and dipteran pests and highlight the gaps in our knowledge in these early events in immune signaling. We also highlight recent advances in identification of the effectors that activate pattern-triggered immunity and those involved in effector-triggered immunity.

Status of research on Drosophila ananassae at global level.

Drosophila, a dipteran insect, has been found to be the best biological model for different kinds of studies. D melanogaster was first described by Meigen in 1830 , is most extensively studied species of the genus Drosophila and a number of investigations employing this species have been documented in areas such as genetics, behaviour, evolution, development, molecular biology, ecology, population biology, etc. Besides D. melanogaster, a number of other species of the genus Drosophila have also been used for different kinds of investigations. Among these, D. ananassae, a cosmopolitan and domestic species endowed with several unusual genetic features, is noteworthy. Described for the first time from Indonesia (Doleschall 1858), this species is commonly distributed in India. Extensive research work on D. ananassae has been done by numerous researchers pertaining to cytology, genetics, mutagenesis, gene mapping, crossing-over in both sexes, population and evolutionary genetics,behaviour genetics, ecological genetics, sexual isolation, fluctuating asymmetry, trade-offs etc. Genome of D. ananassae has also been sequenced. The status of research on D. ananassae at global level is briefly described in this review. Bibliography on this species from different countries worldwide reveals that maximum contribution is from India.

Histone deacetylase enzymes as drug targets for the control of the sheep blowfly, Lucilia cuprina

The Australian sheep blowfly, Lucilia cuprina, is an ecto-parasite that causes significant economic losses in the sheep industry. Emerging resistance to insecticides used to protect sheep from this parasite is driving the search for new drugs that act via different mechanisms. Inhibitors of histone deacetylases (HDACs), enzymes essential for regulating eukaryotic gene transcription, are prospective new insecticides based on their capacity to kill human parasites. The blowfly genome was found here to contain five HDAC genes corresponding to human HDACs 1, 3, 4, 6 and 11. The catalytic domains of blowfly HDACs 1 and 3 have high sequence identity with corresponding human and other Dipteran insect HDACs (Musca domestica and Drosophila melanogaster). On the other hand, HDACs 4, 6 and 11 from the blowfly and the other Dipteran species showed up to 53% difference in catalytic domain amino acids from corresponding human sequences, suggesting the possibility of developing HDAC inhibitors specific for insects as desired for a commercial insecticide. Differences in transcription patterns for different blowfly HDACs through the life cycle, and between the sexes of adult flies, suggest different functions in regulating gene transcription within this organism and possibly different vulnerabilities. Data that supports HDACs as possible new insecticide targets is the finding that trichostatin A and suberoylanilide hydroxamic acid retarded growth of early instar blowfly larvae in vitro, and reduced the pupation rate. Trichostatin A was 8-fold less potent than the commercial insecticide cyromazine in inhibiting larval growth. Our results support further development of inhibitors of blowfly HDACs with selectivity over human and other mammalian HDACs as a new class of prospective insecticides for sheep blowfly.