Fly Life Cycle Research Articles

A Potential Role for Drosophila Mucins in Development and Physiology

Vital vertebrate organs are protected from the external environment by a barrier that to a large extent consists of mucins. These proteins are characterized by poorly conserved repeated sequences that are rich in prolines and potentially glycosylated threonines and serines (PTS). We have now used the characteristics of the PTS repeat domain to identify Drosophila mucins in a simple bioinformatics approach. Searching the predicted protein database for proteins with at least 4 repeats and a high ST content, more than 30 mucin-like proteins were identified, ranging from 300–23000 amino acids in length. We find that Drosophila mucins are present at all stages of the fly life cycle, and that their transcripts localize to selective organs analogous to sites of vertebrate mucin expression. The results could allow for addressing basic questions about human mucin-related diseases in this model system. Additionally, many of the mucins are expressed in selective tissues during embryogenesis, thus revealing new potential functions for mucins as apical matrix components during organ morphogenesis.

Fungal sex as a private matter: odour signals in a specialized pollination‐like insect–fungus mutualism

Fungal sex as a private matter: odour signals in a specialized pollination‐like insect–fungus mutualism

Gene expression analysis in post-embryonic pericardial cells of Drosophila

Increasing evidence suggests conservation of cardiovascular molecules between vertebrates and invertebrates. Vertebrate Rudhira, an evolutionary conserved WD40 protein is expressed during primitive erythropoiesis, neoangiogenesis and tumors. We report here the expression profile of the Drosophila ortholog of Rudhira (DRudh) in the fly life cycle. DRudh is expressed specifically in all post-embryonic pericardial cells (PCs) and garland cells (GCs). This is the first report of a cytoplasmic marker highly specific to post-embryonic PCs. Embryonic PCs belong to three distinct genetic classes based on Odd-skipped (Odd), Even-skipped (Eve) and Tinman (Tin) expression. To identify which among these three classes of PCs expresses DRudh in post-embryonic stages, we analyzed expression of embryonic PC markers in the post-embryonic stages. Unlike in the embryo all larval PCs show an identical gene expression profile. While Odd and Eve expression is mutually exclusive in the embryonic PCs, these two markers are co-expressed in larval PCs but show a distinct subcellular localization. Tin is not expressed in any post-embryonic PC. Additionally larval PCs also express the GATA factor, Serpent (Srp) and the extracellular matrix protein, Pericardin (Prc). While PC number is known to decrease post-embryogenesis, which of the Odd or Eve lineage embryonic PCs persists is not known. Co-expression of the two distinct lineage markers only in post-embryonic stages indicates a complex temporal regulation of gene expression in PCs.

Emergence season of Hypoderma lineatum warbles in southern Punjab, Pakistan

The objective of the present study was to observe the seasonal pattern of the life cycle and the warble stage in bovines of Dera Ghazi Khan and Rajan Pur Districts of Southern-Punjab, Pakistan. The study was conducted from July 2004 to June 2005. The association was studied between various climatic changes and the fly life cycle. The larvae of warble flies were extracted from the backs of naturally infested animals and identified. The adult fly laid eggs in June, and hatched larvae penetrated the skin and followed intensive internal migration to diaphragm, esophageal wall and subcutaneous connective tissue in the month of July. At the start of August they reached the subcutaneous tissue and emergence began. In both species, the maximum warble emergence was found in mid-December and the lowest in mid-March and mid-August. It was concluded that preventive treatment should be adopted before the month of July to avoid carcass depreciation and decreased leather quality.

Drosophila Ecp is a novel ribosome associated protein interacting with dRPL5

Drosophila Ecp is a phylogenetically conserved protein with homologs in most eukaryotes. Studies on Ecp homologs in rat and human suggest those proteins might be involved in cell cycle control, cell proliferation, and learning and memory. However, the molecular function of Ecp itself remains unclear. We show that both the mRNA and protein of ecp are ubiquitously expressed during the entire fly embryogenesis and life cycle. Results of co-immunoprecipitation show that Ecp forms a stable complex with many ribosomal proteins, including dRPL5. The binding of Ecp to dRPL5 was confirmed by GST pulldown. Furthermore, Ecp was found to cosediment with ribosome subunits in a sucrose gradient. These results indicate that Ecp might be a novel ribosome associated protein interacting with dRPL5.

The biological effect of Sepedon (Diptera: Sciomyzidae) fly larvae living on Lymnea snails

Summary The present work was carried out to investigate first, the ecology of the Sepedon flies as well as species of Lymnea snails and secondly, the biological effects of Sepedon fly larvae living on Lymnea. In this regard, the life cycle, death rate and compatibility of Lymnea species, as well as the life cycle of Sepedon flies in breeding cage and the activity of the new larvae in the same ecological condition were investigated. The results showed that Lymnea truncatula needs more sophisticated ecological and feeding conditions than other species of the snails. Lymnea stagnalis was found sensitive to temperature variation and this may lead to gradual or sudden death. Lymnea pregra and Lymnea palustris could well adapt with laboratory conditions. The killing effect (P<0.001) of the third-stage larvae on snails (3 to 4 weeks) was more than the effect of first- and second-stages larvae. This effect was more in a container with 2 cm water depth than a container with 5 cm depth.

Various stages in the life cycle of syrphid flies (Eristalis tenax; diptera: Syrphidae) as potential mechanical vectors of pathogens causing mycobacterial infections in pig herds

We defined the role of the syrphid fly Eristalis tenax in the survival and transmission of mycobacteria in pigs. The conditionally pathogenic mycobacterial (CPM) species Mycobacterium chelonae was isolated from 10 % of liquid dung samples, and both M. chelonae and another CPM species M. fortuitum were isolated from 7 (78 %) of the examined E. tenax larvae collected from the same location. Mycobacteriosis of the lymph nodes of pigs from 3 infected farms was caused by M. avium subsp. avium, M. avium subsp. hominissuis, and M. fortuitum. M. avium subsp. avium and M. avium subsp. hominissuis of identical genotype and serotypes and M. fortuitum were isolated from 7 (1.9 %) larvae, 2 (7.4 %) puparia, and one (1.6 %) imago. The count of colony forming units isolated from larval skin covering (pouch) was higher (p < or = 0.01) than that isolated from the internal organs of larvae. These results showed the potential for E. tenax larvae to spread mycobacteria throughout pig herds and the surrounding environment.

Extrachromosomal circular DNA of tandemly repeated genomic sequences in Drosophila.

One characteristic of genomic plasticity is the presence of extrachromosomal circular DNA (eccDNA). This DNA is found in various eukaryotes from yeast to humans, and its levels are elevated by exposure to carcinogens. eccDNA is heterogeneous in size and composed of chromosomal sequences. In this study we used two-dimensional gel electrophoresis to detect and characterize eccDNA in Drosophila. We found eccDNA throughout the fly's life cycle. These molecules comprise up to 10% of the total repetitive DNA content, and their size ranges from <1 kb to >20 kb. The eccDNA population contains circular multimers of tandemly repeated genes such as histones, rDNA, Stellate, and the Suppressor of Stellate. Multimers of centromeric heterochromatin sequences are included in eccDNA as well. Our findings are consistent with the hypothesis that intramolecular homologous recombination between direct tandem repeats is a favorite mechanism for eccDNA formation. The level of eccDNA increased following MMS treatment of wild-type larvae, consistent with phenomena observed in cultured mammalian cells. This shows mutagen-induced eccDNA formation in the context of the whole organism for the first time. Mutations in the genes okra, mus309, and mei41 did not affect eccDNA under normal conditions or following mutagen treatment, implying that eccDNA formation is different from known pathways of DNA repair.

Fly Larvae in Wastewater Discharges: A Potential Source of Food and Organochlorine Contaminants for some Southern California Fishes

A widely recognized pathway for uptake and accumulation of organic contaminants by demersal fishes is through consumption of infaunal organisms (i.e., those having direct contact with contaminated sediments). Recent studies indicate that demersal fishes near a large sewage outfall in southern California consume larvae of a terrestrial fly, Clogmia albipunctata, which are entrained with the treated effluent and discharged to the ocean. Fly larvae consumption represents a possible method for accumulation of organic contaminants that is unique to marine fishes with non-selective feeding habits that occur near the ocean outfall. An estimated 37–138 kg (wet weight) of fly larvae are discharged daily during summer to the ocean via the Orange County Sanitation Districts (OCSD) wastewater outfall; winter discharges are expected to be lower due to lower production and temperature limitations of the fly life cycle. Fly larvae were present in the guts of ten demersal and pelagic fish species collected near the outfall between July 1993 and August 1998. The highest frequencies of fly larvae (up to 100%) occurred in the guts of white croaker, Genyonemus lineatus, and chub mackerel, Scomber japonicus. Because infauna are still abundant and diverse near the outfall, fly larvae consumption appears to represent a feeding preference instead of a response to lower prey abundances. Fly larvae tissues collected at the wastewater treatment plant contained sub-part-per-million levels of organochlorine compounds, including PCB and DDT. However, lipid-normalized organochlorine concentrations in fly larvae tissues were not appreciably higher than levels in infauna or zooplankton tissues. Although the study design provided only limited sample sizes for some sample types, this initial study suggests that fish consumption of fly larvae represents a mechanism for direct transfer of contaminants and may contribute to uptake and accumulation of lypophyllic organochlorines in fish near the outfall.

A matrix model for studying tsetse fly populations

AbstractSome characteristics of tsetse fly population dynamics were investigated using a matrix model. To take into account the peculiarities of the tsetse fly life cycle, the classic Leslie model was modified. Our model integrated the physiological age group of Glossina females, the pupal and adult survival rate and the pupal life span. The limit of the growth rate was studied and the results were satisfactory when compared with data of tsetse fly mass rearing. The effect of adult and pupal survival rates on the growth rate was examined and confirmed the importance of adult survival. The sensitivity analysis showed that the growth rate was particularly sensitive to change in the survival rate of young nulliparous females. This matrix model, directly accessible to the experimenter, enhanced our understanding of tsetse population dynamics.

Comparison of ecdysteroid production in Drosophila and Manduca: Pharmacology and cross‐species neural reactivity

In both Manduca sexta and Drosophila melanogaster, metamorphic events are driven by ecdysteroids whose production in prothoracic gland (PGs) is stimulated periodically by neural factors. Differences in the life cycle of moths and flies have made it difficult to compare the regulation of ecdysteroid biosynthesis in these two species. As in Manduca, at least two neural factors in the larval Drosophila BVG complex were separable by molecular weight, and they stimulated increased ecdysteroid biosynthesis from the ring gland, a composite organ that includes PG cells. Drosophila neural extracts accelerated ecdysteroid biosynthesis in Manduca PGs and, conversely, partially purified Manduca PTTH preparations elevated ecdysteroid biosynthesis in Drosophila ring glands, suggesting that the two species may share structurally similar prothoracicotropic factors. Drosophila ring glands required the presence of calcium ions to respond to neural extracts, but the phosphodiesterase inhibitor MIX and cAMP analogues exerted little, if any, positive effect on production. Mean ecdysteroid production rates of BVG-ring gland complexes taken from Drosophila larvae during various phases of the wandering period were often submaximal and highly variable, suggesting that they fluctuate widely prior to pupariation. Based on available data in Drosophila and the Manduca model for the control of ecdysteroid biosynthesis, a developmental scheme for neuroendocrine control in Drosophila is proposed.

The developmentally-regulated Drosophila gene rox8 encodes an RRM-type RNA binding protein structurally related to human TIA-1-type nucleolysins.

We report the molecular analysis of a novel Drosophila melanogaster gene, rox8, isolated in a PCR-based screen for sequences encoding RRM-type RNA-binding polypeptides. The rox8 gene is predicted to encode a 50-kilodalton protein displaying extensive amino acid sequence similarities (46% overall identity; 57 to 60% similarity) to the two recently described human TIA-1-type nucleolysins. These cytolytic granule associated proteins, which bind polyadenylated sequences in vitro and trigger DNA fragmentation in permeabilized target cells, are suspected to participate in the apoptotic cell death pathway induced by T-lymphocytes and natural killer cells. The structural relatedness of the three proteins includes three tandemly-repeated consensus RNA-recognition motifs at the N-terminal end and a putative membrane targeting signal at the C-terminal end. rox8 cytologically maps to 95D5-9 on the right arm of the third chromosome. Two rox8 transcripts of 3 and 3.3 kb in length, respectively, result from a developmentally-modulated alternative usage of different polyadenylation sites and are differentially accumulated throughout the fly life cycle. Molecular characterization of rox8 represents the first step in a genetic analysis of the potential roles of a TIA-1-related protein in RNA metabolism and/or programmed cell death in Drosophila.

Cutaneous Myiasis Caused by the African Tumbu Fly (Cordylobia anthropophaga)

We describe a patient with cutaneous myiasis caused by the African tumbu fly (Cordylobia anthropophaga). This case demonstrates the need for a detailed travel history and an understanding of the fly life cycle to prevent erroneous diagnosis and to expedite prompt treatment. The nature of the lesions, larval morphological features, histological characteristics, and immune response directed toward fly maggots are described.

The expression of the gene coding for alcohol dehydrogenase during the development of Drosophila melanogaster

The gene coding for the abundant enzyme alcohol dehydrogenase (EC 1.1.1.1) in Drosophila melanogaster is transcribed from one of two different promoters, 708 bp apart, at different stages of the fly's life cycle. Transcripts from both “distal” and “proximal” promoters are maternally inherited by the zygote and both rapidly decay. Nine hours after egg laying transcription of the zygotic genome begins, initially from both Adh gene promoters. However, only the proximal transcript continues to accumulate and, by the mid-third larval instar, is a very abundant RNA. Quite suddenly the level of this transcript falls. At the same time a transcript from the distal promoter transiently accumulates. The level of Adh transcripts are very low throughout pupal and pharate adult development. The amount of the distal transcript begins to rise, some 15 hr before eclosion; suddenly, at eclosion of the adult fly, the level of this transcript increases several fold. The change in pattern of transcription, from proximal to distal promoters, can occur in a single tissue, and probably in a single cell, without cell division.

Expression of ras cellular oncogenes during development of Drosophila melanogaster.

The transcription patterns of three v-Ha-ras-related cellular oncogenes in Drosophila melanogaster were studied. Each gene coded for at least two distinct transcripts. The larger transcript of each gene was expressed at a similar abundance during the entire life cycle of fruit flies, whereas the shorter transcripts were much more abundant in embryonic stages than at later stages.

Expression of ras cellular oncogenes during development of Drosophila melanogaster.

The transcription patterns of three v-Ha-ras-related cellular oncogenes in Drosophila melanogaster were studied. Each gene coded for at least two distinct transcripts. The larger transcript of each gene was expressed at a similar abundance during the entire life cycle of fruit flies, whereas the shorter transcripts were much more abundant in embryonic stages than at later stages.

THE BIOLOGY OF POLLENIA RUDIS, THE CLUSTER FLY (DIPTERA: CALLIPHORIDAE): IV. A PRELIMINARY MODEL OF THE CLUSTER FLY LIFE CYCLE, AND SOME POSSIBLE METHODS OF BIOLOGICAL CONTROL

AbstractTo relate the various details of the cluster fly life cycle which have recently appeared in the literature, a preliminary mathematical model is constructed When used to interpret the population data of De Coursey, the relationships of the model were shown to be at least qualitatively sound. From an examination of the parameters which modify the components of the model, some possible control measures are suggested.

Activity of a transfer RNA modifying enzyme during the development of Drosophila and its relationship to the su(s) locus

The Chromatographie elution profiles of radioactively labeled asparaginyl, aspartyl, histidyl and tyrosyl-tRNA's from different developmental stages of Drosophila melanogaster have been examined. The relative proportions of certain chromatographically distinct forms of these four tRNA's are altered in a similar way during the life cycle of wild-type flies. These four tRNA's show a further quantitative change in flies of the genotype su(s) 2v;bw . Two-dimensional thin-layer chromatograms of pancreatic RNase digests of the two major tRNA Asp Chromatographie forms revealed almost identical patterns. Two-dimensional thin-layer chromatograms of piperidine hydrolysates of these tRNA's revealed that one contained a nucleotide similar to Qp, an unidentified nucleotide occurring in Escherichia coli tRNA. It was concluded that these Chromatographie forms are homogeneic † † We propose the term homogeneic to describe tRNA's having the same sequence and presumably being products of the same gene, but which are cbromatographically distinct because of different degrees of post-transcriptional modification. , the difference between them being the extent of the modification of one nucleotide. The su(s) 2v;bw mutant appears to be altered in some aspect of this modification process.

Esterase Activity and Susceptibility to Parathion at Different Stages in the Life Cycle of Organophosphorus-Resistant and Susceptible House Flies

Quantitative determinations utilizing colorimetric techniques were made on cholinesterase (ChE) and aliphatic-esterase (Ali-E) activity at different stages in the life cycle of a susceptible and two organophosphorus-resistant strains of the house fly ( Musca domestica L.). The toxicity of parathion residues to larvae, pupae. and adults of a susceptible and parathion-resistant strain was also determined. It was found that, as in the adults, levels of Ali-E activity were markedly less when the resistant flies were in immature stages. ChE levels were similar for all fly strains at the stages of the life cycle tested. Larvae and pupae of the parathion-resistant strain possessed a degree of resistance approximately equal to that present in adult flies. The variation in susceptibility of the different stages tested did not appear to be correlated with variations in the amount of either ChE or Ali-E present.