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At least 19 recordsLinked to original sources

The housefly (Musca domestica) as a carrier of pathogenic microorganisms in a hospital environment.

Houseflies have long been regarded as potential carriers of microorganisms. Since pathogenic microorganisms are widespread in the hospital environment, there is abundant opportunity for flies to become contaminated and, in turn, to contaminate the patient environment. In the present study, an attempt was made to isolate and identify pathogenic bacteria, fungi and parasites from the housefly Musca domestica collected in the surgical ward of the All India Institute of Medical Sciences Hospital and also in a remote residential area located 5 km from the hospital. A total of 113 flies were collected: 65 from a surgical ward (test) and 48 from a residential area for comparison. Ten genera of bacteria were isolated from the test group of flies compared with nine from the control group. In primary isolations, it was observed that the load of bacteria carried by the test group of flies was significantly more (P less than 0.001) than for the control flies. Pseudomonas aeruginosa, Enterococcus faecalis and viridans streptococci were isolated only from the test flies. The isolation rate of Staphylococcus aureus was significantly higher (P less than 0.001) in test houseflies than in the control houseflies. There was no significant difference in isolation of parasitic ova and cysts from test and control houseflies. Candida spp. were isolated in almost equal numbers from both groups of houseflies, yet none of these was Candida albicans. Houseflies therefore may act as vectors of potentially pathogenic bacteria in a hospital environment.

Animals

Contrasting patterns of DNA sequence arrangement in Apis mellifera (honeybee) and Musca domestica (housefly).

We have examined the organization of the repeated and single copy DNA sequences in the genomes of two insects, the honeybee (Apis mellifera) and the housefly (Musca domestica). Analysis of the reassociation kinetics of honeybee DNA fragments 330 and 2,200 nucleotides long shows that approximately 90% of both size fragments is composed entirely of non-repeated sequences. Thus honeybee DNA contains few or no repeated sequences interspersed with nonrepeated sequences at a distance of less than a few thousand nucleotides. On the other hand, the reassociation kinetics of housefly DNA fragments 250 and 2,000 nucleotides long indicates that less than 15% of the longer fragments are composed entirely of single copy sequences. A large fraction of the housefly DNA therefore contains repeated sequences spaced less than a few thousand nucleotides apart. Reassociated repetitive DNA from the housefly was treated with S1 nuclease and sized on agarose A-50. The S1 resistant sequences have a bimodal distribution of lengths. Thirty-three percent is greater than 1,500 nucleotide pairs, and 67% has an average size about 300 nucleotide pairs. The genome of the housefly appears to have at least 70% of its DNA arranged as short repeats interspersed with single copy sequences in a pattern qualitatively similar to that of most eukaryotic genomes.

Animals

Chlorocyclohexane insecticides and male medfly attractants: similar stereospecificity for neuroactivity and interactions with a housefly [35S]t-butylbicyclophosphorothionate binding site.

[35S]t-Butylbicyclophosphorothionate [( 35S]TBPS) undergoes saturable specific binding to a membrane preparation from housefly thoraxes and abdomens with apparent Kd and Bmax values at equilibrium of 0.17 microM and 2.2 pmol/mg protein at 20 degrees C. Lindane is more potent than three other isomers of hexachlorocyclohexane as a toxicant for houseflies and in displacing [35S]TBPS from this housefly membrane preparation. This correlation of similar stereospecificity for neuroactivity and interaction with the TBPS receptor extends to the Mediterranean fruit fly male attractant trimedlure and its components and analogs. The relative attractancy of t-butyl cis-4-chloro-trans-2-methylcyclohexanecarboxylate and of three less active isomers of this trans-chlorocyclohexane-carboxylate parallel their potency in the [35S]TBPS binding assay. With both trimedlure and the related cyclohexene attractant siglure the trans-isomers are more potent than the cis-isomers as attractants and in displacing [35S]TBPS. Scatchard analyses indicate that lindane binds at the same site as [35S]TBPS. The hexachlorocyclohexane isomers and trimedlure components are much more potent inhibitors with membrane preparations from houseflies than from rat brain. The housefly TBPS receptor possibly serves as a model for the primary target sites, thereby suggesting that both the insecticide and the attractant may interact with some component of the putative GABAergic nervous or neuromuscular system.

Animals

Induction of multiple cytochrome P-450 species in housefly microsomes--SDS-gel electrophoresis studies.

1. Microsomal fractions isolated from various housefly strains have been characterized with respect to multiple forms of cytochrome P-450 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. 2. Susceptible NAIDM houseflies were pretreated with known inducers of cytochrome P-450, and their microsomal electrophoretic profiles were compared to control NAIDM microsomes, using as standards partially purified cytochrome P-450s from noninduced NAIDM houseflies. 3. Tentatively, at least five different species of cytochrome P-450 may exist in the NAIDM housefly strain. 4. A comparison of the microsomal electrophoretic profile of different housefly strains also indicates the presence of at least two additional cytochrome P-450 species. 5. Induction with alpha-pinene and phenobarbital was expressed by a shift of the maximum absorbance at 452 nm in the CO-difference spectrum to lower wavelengths in the NAIDM strain; whereas, beta-naphthoflavone, although increasing the amount of cytochrome P-450, did not change the wavelength of maximum absorbance. 6. Cytochromes of the P-452 type appear to predominate in the susceptible NAIDM strain, while cytochromes of the P-450 and P-448 types predominate in resistant strains.

Animals

Effect of age and ambient temperature on n-pentane production in adult housefly, Musca domestica.

The objective of this study was to examine the relationship between lipid peroxidation and aging in the male housefly. Metabolic rate of flies is known to be higher and life span shorter at elevated ambient temperature. Evolution of n-pentane and level of thiobarbituric acid (TBA) reactive material were used as indicators of lipid peroxidation. n-Pentane accumulated by houseflies in vivo and by whole body homogenates of houseflies, in response to tert-butyl hydroperoxide (1 mM), increased with age. n-Pentane accumulation in vivo was markedly higher at higher ambient temperature. Furthermore, n-pentane generated by flies in vivo and by fly homogenates in vitro tended to be lower in flies raised at a lower ambient temperature. TBA-reactive material, elicited by tert-butyl hydroperoxide, was augmented in older flies, but no significant difference was found between flies aged at different ambient temperatures. Analysis of fatty acids in housefly homogenates indicated an age-associated increase in the ratio of polyunsaturated to saturated fatty acids.

Aging

Houseflies (Musca domestica) as mechanical vectors of shigellosis.

Houseflies (Musca domestica) are mechanical vectors of Shigella organisms. Seasons during which both flies and cases of dysentery are prevalent often coincide. Houseflies have an affinity for human excrement and, as documented by bacteriologic culture of trapped flies, become contaminated with Shigella organisms following contact with infected human feces. The inoculum required to transmit shigellosis is only 10-10(2). Since houseflies cohabit with humans, they can readily contaminate food and eating utensils. With the advent of insecticides in the 1940s, intervention studies in the United States provided evidence of the role of the housefly in transmission of shigellae. In towns that were exposed to fly-control measures, the density of flies and the prevalence of carriage of Shigella organisms, diarrhea, and mortality due to diarrheal disease among young children all markedly diminished as compared with the situation in control towns. Investigations that quantitate the importance of fly-borne transmission of Shigella organisms relative to other modes of transmission and that provide evaluation of measures to diminish fly-borne transmission are warranted in developing areas.

Animals

The role of the housefly, Musca domestica, in the spread of Aujeszky's disease (pseudorabies).

Starved houseflies were held over a suspension of Aujeszky's virus (PRV-1) for 24-48 h. One group was rinsed in 70% ethanol to kill virus attached to the body surface. No virus was isolated from this group. For the other group the titre of virus decreased more rapidly on the body surface of flies than in the environment. Model experiments demonstrated that the Aujeszky's virus cannot survive in the body of the housefly but the body surface may be contaminated for a period of time depending on the initial viral titre. Experiments showed that susceptible pigs fed on flies contaminated with Aujeszky's virus may become infected. The quantity of virus (5 x 10(5) pfu ml-1) shed by a single housefly during biting and vomiting on the cornea or abraded skin proved to be sufficient to cause infection in susceptible pigs, rabbits and a lamb. It is possible that houseflies could play a role in transmission of infection within herds. Transmission between herds is much less likely.

Animals

Cytochrome P-450 in the housefly: induction, substrate specificity and comparison to three rat hepatic isoenzymes.

1. Both phenobarbital and clofibrate pretreatment cause a qualitative change in cytochrome P-450 content in housefly (Musca domestica). Based on changes in substrate specificity, both inducing agents appear to cause induction of an isoenzyme (or group of isoenzymes) of cytochrome P-450 in housefly, and this response is similar in extent and effect to that described in rodents. 2. Using Western blot analysis and probing with antibodies to three rat hepatic isoenzymes (P450 IA1, P450 IIB1 and P450 IVA1), common structural epitopes with housefly cytochrome P-450 were sought. Despite similarities in patterns of induction and catalytic function, little evidence for structural commonality between the cytochrome P-450 in rat and housefly was observed.

Animals

Early season dispersal of Muscidifurax zaraptor (Hymenoptera: Pteromalidae) utilizing freeze-killed housefly pupae as hosts.

The pteromalid wasp, Muscidifurax zaraptor Kogan and Legner, was released at three locations at a dairy in May before housefly and stable fly breeding had begun. Freeze-killed housefly pupae were placed adjacent to the emerging parasites at biweekly intervals for a 6-week period. Hosts placed out weeks 0 and 2 were heavily parasitized. Decreased parasitism in hosts placed out at week 4 suggested that many of the M. zaraptor had dispersed or died. High parasitism of hosts placed in the field at week 6 was the result of second generation parasites emerging from pupae placed out at week 0. Parasitism of freeze-killed housefly pupae placed 6 m and in the four cardinal directions from the release points was similar but lower than for hosts placed adjacent to the emerging parasites. The study demonstrated that emerging M. zaraptor readily utilized nearby freeze-killed housefly pupae but the availability of these hosts did not deter the parasites from searching for additional hosts.

Animals

Developmental patterns in the antioxidant defenses of the housefly, Musca domestica.

The activities of superoxide dismutase (SOD), catalase, glutathione peroxidase, glutathione S-transferases, GSSG reductase, thiol transferases, gamma glutamylcysteine synthetase, and glucose-6-phosphate dehydrogenase, and the concentrations of H2O2 and reduced and oxidized glutathione were determined in the various developmental stages of houseflies. Housefly development was correlated with a progressive increase of cellular oxidizing equivalents and a loss of cellular reducing capacity. The loss of reducing equivalents appeared to result from a decrease in the activity of enzymes involved in glutathione and NADPH synthesis and a concomitant increase in glutathione-oxidizing enzymes. Relatively little change was observed in SOD activity during housefly development; however, the electrophoretic pattern of MnSOD varied in a manner specific to developmental stage. A striking increase in H2O2 concentration occurred prior to pupation possibly due to changes in substrate catabolism. These results support the hypothesis that the cellular environment becomes progressively more oxidizing during development.

Animals

Long-chain (Z)-9-alkenes are "psychedelics" to houseflies with regard to visually stimulated sex attraction and aggregation.

Three different tests on houseflies (Musca domestica L.) revealed that both pheromone-free pseudoflies and male partner flies exhibit in the presence of mixtures of long-chain (Z)-9-alkenes or pure (Z)-9-tricosene enhanced releasing effects for two optical cues, which stimulate male houseflies to mating strikes and houseflies of both sexes to aggregation.

Alkenes

Regulation of sex pheromone biosynthesis in the housefly, Musca domestica: relative contribution of the elongation and reductive steps.

The regulation of production of the sex pheromone (Z)-9-tricosene (Z9-23:Hy) in the housefly, Musca domestica, was studied by examining the chain length specificity of the fatty acyl-CoA elongation reactions and the reductive conversion of fatty acyl-CoAs to alkenes in 1- and 4-day-old male and female houseflies. Microsomal preparations from 4-day-old female insects produced as the predominant alkene Z9-23:Hy when incubated with malonyl-CoA, NADPH, and [9,10-3H2]oleoyl-CoA (18:1-CoA), whereas microsomal preparations from 4-day-old male insects produced predominantly (Z)-9-heptacosene (Z9-27:Hy). These are the major alkenes produced in vivo by Day 4 females and males, respectively. Microsomes prepared from both Day 1 males and Day 1 females produced Z9-27:Hy as the major alkene from labeled 18:1-CoA. This is the major alkene produced in vivo by both sexes at Day 1. An examination of the chain length specificity of the elongation reactions showed that microsomes prepared from Day 4 male insects readily elongated both 18:1-CoA and 15-[15,16-3H2]tetracosenoyl-CoA (24:1-CoA) to 28-carbon moieties, whereas microsomes from Day 4 female insects did not efficiently elongate either substrate beyond 24 carbons. With high substrate concentrations, microsomes prepared from male insects converted 24:1-CoA to Z9-23:Hy more efficiently than did those from females, whereas under lower and presumably more physiological substrate concentrations, microsomes from females had slightly higher activity than did those from males. Taken together, these data show that the regulation of the chain length of the alkenes, and thus sex pheromone production, in the housefly resides predominantly in the elongation reactions and not in the step which converts the fatty acyl-CoA to hydrocarbon.

Acyl Coenzyme A

Correlation between life expectancy, flightlessness and actomyosin adenosine triphosphatase activity in the housefly, Musca domestica.

The objective of this investigation was to determine if actomyosin ATPase activity in flight muscles is correlated with life expectancy of houseflies. All houseflies lose flying ability before death which permits the identification of shorter-lived flightless 'crawlers' from their longer-lived cohorts, the 'fliers'. Life expectancy of crawlers is about one-third shorter than that of the fliers. Flying performance of houseflies, as measured by the total duration of flying activity during 1 h periods, average duration of flights and the number of rest stops, was highest at 4 days of age and declined thereafter. Actomyosin ATPase activity was higher in the fliers than in the crawlers of the same age. Abolition of flight, by surgical removal of wings at 1 day of age, had no effect on the enzyme activity. Results are interpreted to suggest that actomyosin ATPase activity is correlated with physiological rather than chronological age of flies.

Adenosine Triphosphatases

Age-related changes in the redox status of the housefly, Musca domestica.

The objective of this study was to further test the hypothesis that aging in the housefly is associated with increased oxidative stress. Age-related changes in the concentration of glutathione, NAD and NADP, which undergo oxidation-reduction reactions, and of H2O2, a potent cellular oxidant, were examined in the homogenates of adult male houseflies at 4, 8, 12 and 16 days of age. Sixteen days of age represents the beginning of the dying phase of the population when about 20% mortality usually occurs. Results indicate that the ratios of reduced/oxidized forms decline with age; H2O2 concentration steadily increases with age. Results suggest that the intracellular redox potential of the housefly becomes progressively more pro-oxidizing or less reducing during the aging process.

Aging

[35S]t-butylbicyclophosphorothionate binding sites in susceptible and cyclodiene-resistant houseflies.

4-aminobutyric acid (GABA)-gated chloride ion channels are important molecular targets for a number of polychlorocycloalkane compounds including cyclodiene insecticides. Previous radioligand binding studies have indicated that cyclodiene insecticides are potent inhibitors of [35S]t-butylbicyclophosphorothionate ([35S]TBPS) binding to housefly thorax and abdomen membranes. In the present study, a laboratory-reared, cyclodiene-resistant (CYW) housefly strain (Musca domestica) showed resistance to a number of cyclodiene insecticides. Specific, saturable [35S]TBPS binding was detected in thorax and abdomen membranes prepared from housefly strains susceptible (CSMA) and resistant (CYW) to cyclodienes. Scatchard analysis of [35S]TBPS binding data from CSMA and CYW membranes revealed no significant differences between the two strains in either the affinity (Kd) or the density (Bmax) of specific, saturable binding sites. There were no differences in the comparative effectiveness of a range of polychlorocycloalkanes, including cyclodiene insecticides, as inhibitors of specific [35S]TBPS binding to CSMA and CYW thorax and abdomen membranes. Therefore, if an alteration in target site is a mechanism for resistance to cyclodienes in the CYW strain, it is not readily measurable using [35S]TBPS.

Animals

Effect of age on endogenous DNA single-strand breakage, strand break induction and repair in the adult housefly, Musca domestica.

It has been suggested that genomic alterations involving DNA damage and the ability to repair such damage play an important role in cellular senescence. In this study, endogenous DNA single-strand breaks, the susceptibility of DNA to induced strand breakage and the capacity to repair these breaks were compared in postmitotic cells from young (3-day-old) and old (23-day-old) houseflies. DNA single-strand breaks did not accumulate during normal aging in the housefly. However, cells of the old flies exhibited a greater sensitivity to single-strand breakage induced by gamma-radiation and UV light. The capacity to repair these exogenously induced single-strand breaks declined with age. Results do not support the view that DNA single-strand breaks are a causal factor in aging in the housefly. An age-related increase in the susceptibility to undergo single-strand breakage suggests alterations in chromatin during the aging process.

Aging