Musca domestica L D.

Field strains of the house fly (Musca domestica L. Diptera: Muscidae) were collected in April and September 2002 from cow farms (Antalya, Izmir) and garbage dumps (Adana, Ankara, Istanbul, Sanliurfa) in Turkey. The resistance levels of first to fifth generation offspring were evaluated against six insecticides (cypermethrin, cyphenothrin, deltamethrin, permethrin, resmethrin, fenitrothion). Resistance levels for pyrethroid group insecticides ranged from 23.27 (permethrin-Istanbul fall strain) to 633.09 (cypermethrin-Izmir spring strain) and for fenitrothion ranged from 5.78 (Istanbul fall strain) to 51.04 (Antalya spring strain). Our results showed that pyrethroid resistance was high and changed from spring to fall in relation to usage and application frequencies of these compounds at the study sites. Although fenitrothion resistance levels were determined to be lower than pyrethroids, these levels were still high and led to control failure. Flies from cow farms were more resistant than those from garbage dumps, but resistance levels for Sanliurfa and Adana strains were also high in relation to usage of different insecticides for agricultural purposes. Although resistance levels against different pyrethroids decreased from spring to fall, these levels still indicated the presence of a strong selective pressure on the populations.     

Kynurenine hydroxylase in Musca domestica L.

1. Kynurenine hydroxylase activity was assayed in extracts of Musca domestica L. 2. During the life cycle of the fly, there is a peak of enzyme activity shortly after pupation. 3. Eye-color mutants, rb2, rb1; rb2 and cm, show reduced activity during pupal stages. 4. An ocra mutant lacks this activity. 5. The rb1 and rb2 mutations were separated from the rb1; rb2 strain. From measurements of the xanthommatin content, the rb1 mutation was suggested to enhance the expression of the rb2 gene.     

Temporal expression of ornithine decarboxylase in developing embryos of Musca domestica

The objective of this study was to partially characterize and follow the temporal expression of the enzyme ornithine decarboxylase (ODC) throughout embryonic and early larval development of Musca domestica. Enzymatically active ODC was shown to be present at detectable levels in the embryos only during the latter stages of embryogenesis. This temporally expressed enzyme displayed maximum activity at the time of hatching, and the activity rapidly declined in the newly hatched larvae. The half-life of ODC activity in extracts at the time of hatching and 30 min after hatching was 57 min and 12 min, respectively. The subunit molecular weight of the embryonic ODC was determined to be 46,000, and the apparent native molecular weight was determined to be 276,000. The concentrations of the polyamines putrescine, spermidine, and spermine also were determined throughout embryogenesis. Spermidine was found to be present in the embryos at about 10-fold higher concentrations than spermine and at about 100-fold higher concentrations than putrescine. These polyamines did not undergo major changes in concentration throughout development of the embryos.     

Genetical experiments on the gene for low aliesterase activity and organophosphate resistance in Musca domestica L.

In order to locate gene a for low aliesterase activity and OP-resistance, a diazinon resistant strain was crossed with several strains carrying recessive marker genes. The phenotypic expression of the a gene studied was diazinon resistance, and a discriminating dose was employed to classify aa ⁺ and a ⁺ a ⁺ flies obtained in the crosses.Resistance was found to segregate in opposition to ar and cm, indicating that the genes a, ar and cm are located on the same (fifth) chromosome. Crossovers between a and the markers were either rare or completely absent.During the course of these experiments a strain carrying the marker bwb proved to be heterogeneous as to its aliesterase activity. A factor was shown to be present which caused low aliesterase activity but no diazinon or malathion resistance. This factor could be either a new allele of gene a or a deficiency.

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Zusammenfassung Um das Gen a für niedrige Aliesterase-Aktivität und Phosphorester-Resistenz zu lokalisieren, wurde ein diazinonresistenter Stamm mit verschiedenen Stämmen welche rezessive Gene enthalten, gekreuzt. Um die aa ⁺- und a ⁺ a ⁺-Fliegen dieser Kreuzung klassifizieren zu können, wurde als phaenotypisches Merkmal die Diazinon-Resistenz und eine discriminating dose benutzt.Es war festzustellen, daß die Gene a, ar und cm auf ein und demselben (fünften) Chromosom lokalisiert sind. Crossing-over zwischen a und den Markierungsgenen kam selten oder nie vor.Im Verlauf dieser Versuche wurde festgestellt, daß ein Stamm, der das Markierungsgen bwb enthielt, heterogen zu seiner Aliesterase-Aktivität war. Ein Faktor, der niedrige Aliesterase-Aktivität, aber keine Diazinon- oder Malathion-Resistenz verursachte, konnte ermittelt werden. Dieser Faktor stellt entweder ein neues Allel des Gens a oder eine Defizienz im Chromosom dar.

     

Factors affecting the toxicity of diazinon to Musca domestica L

Processes affecting the toxicity of diazinon to a susceptible and a resistant strain of houseflies were examined. More evidence was obtained to show that slower penetration of diazinon through the integument of resistant flies is a cause of resistance. Small amounts of two decomposition products were found in both strains. The decomposition mechanisms, in these strains were differently distributed and, although detoxication of diazinon in the two strains is quantitatively similar and small, it may contribute to resistance. Traces of diazoxon were detected when diazinon was incubated with tissue extracts of either strain. Tissue extracts of resistant, but not of susceptible, flies decomposed significant amounts of diazinon in 1 hr. and the ability to decompose diazoxon seems to be an important cause of resistance. Tissues of both strains sorbed diazinon from aqueous solution similarly; the quantities sorbed were large and suggest that sorption may increase the amount of poison needed inside the insects to kill, by between five and forty times.     

Superoxide dismutase in the housefly,Musca domestica (L.)

Four superoxide dismutase (SOD) (E.C. 1.15.1.1) isozymes were present in whole tissue homogenates of Musca domestica when examined by polyacrylamide gel electrophoresis. One of the isozymes contained manganese, and the other three contained copper and zinc. All were observed in each of the body tagma (head, abdomen, and thorax) and at each developmental stage (egg to adult). The copper- and zinc-containing isozymes purified from newly emerged, adult M. domestica had a relative molecular weight of 34,800 as determined by gel filtration chromatography but consisted of two equal-size subunits of 16,000 as measured by sodium dodecylsulfate polyacrylamide gel electrophoresis. An isoelectric point between 4.8 and 5.1 was measured. Approximately 2 mol each of copper and zinc were present per dimer. The three copper, zinc isozymes were identified as charge variants. The amino acid composition of the enzyme was similar to that of copper, zinc-containing superoxide dismutases from other sources. Purified housefly copper, zinc superoxide dismutase was neither deactivated nor able to protect lactic dehydrogenase against deactivation in the presence of light and rose bengal, a known generator of singlet oxygen. The role of SOD in the phototoxic reaction involving rose bengal is discussed.     

Distribution of heterochromatin on the mitotic chromosomes of Musca domestica L. in relation to the activity of male-determining factors

In the housefly, male sex is determined by a dominant factor, M, located either on the Y, on the X, or on any of the five autosomes. M factors on autosome I and on fragments of the Y chromosome show incomplete expressivity, whereas M factors on the other autosomes are fully expressive. To test whether these differences might be caused by heterochromatin-dependent position effects, we studied the distribution of heterochromatin on the mitotic chromosomes by C-banding and by fluorescence in situ hybridization of DNA fragments amplified from microdissected mitotic chromosomes. Our results show a correlation between the chromosomal position of M and the strength of its male-determining activity: weakly masculinizing M factors are exclusively located on chromosomes with extensive heterochromatic regions, i.e., on autosome I and on the Y chromosome. The Y is known to contain at least two copies of the M factor, which ensures a strong masculinizing effect despite the heterochromatic environment. The heterochromatic regions of the sex chromosomes consist of repetitive sequences that are unique to the X and the Y, whereas their euchromatic parts contain sequences that are ubiquitously found in the euchromatin of all chromosomes of the complement. Received: 20 February 1998; in revised form: 11 May 1998 / Accepted: 23 May 1998     

Membrane specializations in the peripheral retina of the housefly Musca domestica L.

Membrane specializations of the peripheral retina of the housefly (Musca domestica) are revealed in thin sections and freeze fracture/etch replicas. Septate junctions are abundant in corner areas of the pseudocone enclosure bonding: between homologous corneal pigment cells (CPC); between homologous large pigment cells (LPC); between CPC-LPC; between Semper cells (SC); between SC-CPC. Spot desmosomes are present between Semper cells. It is likely that septate junctions function as strengthening adhesions in this area. A new membrane specialization similar to a continuous junction was observed between retinular cells of the same or adjacent ommatidium. This junction has indistinct septa in the 115 A intermembrane cleft and is intermittent in character. When this junction is absent, the apposed cells gape apart. In freeze fracture studies, this junction is characterized by bridges composed of fused membrane particles and randomly arranged particles on the P face, and noncorresponding grooves on the E face. The ridges are elongate and roughly parallel and sometimes they form enclosures. Mitochondria line up along these junctions, often within 90 A of the unit membrane. This membrane specialization has characteristics of tight and continuous junctions. In line with previous findings, we suggest that this junction assists in retinular cell orientation, possibly in enforcing the ommatidial twist and in maintaining localized ionic concentration gradients between retinular cells.     

Endonuclease activity of phenol oxidase from Musca domestica larvae

Phenol oxidase (PO), a copper-containing enzyme with oxygenase activity, can convert mono- or diphenol into quinone and plays an important role in the arthropod melanization reaction. Here, we report a new property of PO from Musca domestica larvae: a thermotolerant endonuclease activity, by which PO can degrade plasmid DNA even after being heated to 80 degrees C for 20 min. We cloned PO cDNA, constructed the expression vector pVAX1-PO, and expressed it in HeLa cells. The expression product showed the same properties as purified PO. Our data indicate that PO is a bifunctional enzyme, exhibiting both oxygenase and endonuclease activity, suggesting new roles for this important molecule in the innate responses of M. domestica.     

Influence of procaine HCl on larval development, adult lifespan and acid phosphatase activity in Musca domestica L

By treating larvae of Musca domestica L. with 4 x 10(-4%) procaine HCl we could shorten larval development, decrease larval mortality and increase number of adult offspring. A high concentration of procaine HCl (0.4%) caused a prolongation of the larval development, a lower pupal weight and a decreased number of adult offspring, which are, in our opinion, indications of a toxic effect. The effects of procaine HCl on ageing and acid phosphatase activity are not so clear. The distribution of subpopulations in a population and the correlation with acid phosphatase activity during adult lifespan are discussed.