Background: The occurrence of bacterial infections sometimes involves synanthropic flies and cockroaches, as mechanical vectors of pathogenic microorganisms. The aim of this study was to identify the different species...Background: The occurrence of bacterial infections sometimes involves synanthropic flies and cockroaches, as mechanical vectors of pathogenic microorganisms. The aim of this study was to identify the different species of flies and cockroaches that cohabit with humans in the city of Cotonou and determine the contribution of Musca domestica and Periplaneta americana in the transmission of bacteria responsible for infections in humans. Methods: Capture sessions during the day for flies and at night for cockroaches were carried out in 4 arrondissements of the city of Cotonou. The insects collected were transported to the Center of Research Entomological of Cotonou for identification, then sent to the Section Hygiene of Water and Food for microbiological analysis, enumeration and testing for human pathogenic bacteria. Results: A total of 351 flies and 26 cockroaches were collected at the sites, including two synanthropic species belonging to two families each. Musca domestica and Periplaneta americana were the most abundant species found after identification in the city of Cotonou. Thermo-tolerant coliforms and Escherichia coli were found on all specimens at varying concentrations. Salmonella spp. bacteria were identified in the fly population from the Dantokpa dump. Conclusion: Flies and cockroaches can transmit microorganisms to humans. The presence of Salmonella spp. among the specimens revealed that infections frequently caused by contaminated food or water are also transmitted to humans by flies. The presence of these germs on flies and cockroaches represents a potential risk of mechanical transmission to humans. It is, therefore, essential to continue investigations in order to assess the species of bacteria propagated, improve control strategies against these troublesome insects and adopt better hygiene conditions for better living.展开更多
The inhibition effect of chitooligosaccharides from housefly larvae on pathogens ofcrops seeds, fruits or vegetables was studied and the main factors influencing theantimicrobial activity of chitooligosaccharides were...The inhibition effect of chitooligosaccharides from housefly larvae on pathogens ofcrops seeds, fruits or vegetables was studied and the main factors influencing theantimicrobial activity of chitooligosaccharides were also investigated. It was foundthat chitooligosaccharides from housefly larvae had wide spectrum fungistasis. It canstrongly inhibit the development of 31 kinds of plant pathogenic fungi such as corticiumrolfsii Saccardo. The results indicated that the degree of deacelylation (DD) or theaverage molecular weight(MW)of chitooligosaccharides were related to the antimicrobialactivity. The antimicrobial activity increased with the rising of DD or the declining ofMW. Pot culture results showed that chitooligosaccharide could enhance the rate ofgermination and emergence of the seeds of maize, wheat and cotton. Chitooligosaccharidehad certain effect on corn southern leaf blight caused by Helminthosporium maydis.展开更多
Objective To better comprehend the molecular structure and physiological function of the housefly larval peritrophic matrix （PM）, a mass spectrometry approach was used to investigate the PM protein composition. Meth...Objective To better comprehend the molecular structure and physiological function of the housefly larval peritrophic matrix （PM）, a mass spectrometry approach was used to investigate the PM protein composition. Methods The PM was dissected from the midgut of the third instar larvae, and protein extracted from the PM was evaluated using SDS-PAGE. A 1D-PAGE lane containing all protein bands was cut from top to bottom, the proteins in-gel trypsinised and analysed via shotgun liquid chromatography- tandem mass spectrometry （LC-MS/MS）. Results In total, 374 proteins, with molecular weights varying from 8.225, kD to 996.065 kD and isoelectric points ranging from 3.83 to 11.24 were successfully identified, most identified proteins were mainly related to immunity, digestion, nutrient metabolism and PM structure. Furthermore, many of these proteins were functionally associated with pattern binding, polysaccharide binding, structural constituent of peritrophic membrane and chitin binding, according to Gene Ontology annotation. Conclusion The PM protein composition, which provides a basis for further functional investigations of the identified proteins, will be useful for understanding the housefly larval gut immune system and may help to identify potential targets and exploit new bioinsecticides.展开更多
To reveal the insecticidal mechanism of terpinen-4-ol, the activity of Na＋,K＋-ATPase in insects tested were determined in vivo and in vitro. The results showed that terpinen-4-ol and its ester derivatives had strong...To reveal the insecticidal mechanism of terpinen-4-ol, the activity of Na＋,K＋-ATPase in insects tested were determined in vivo and in vitro. The results showed that terpinen-4-ol and its ester derivatives had strong contact activity to housefly and the contact toxicities of its derivatives except Z3 were all superior or equivalent to terpinen-4-ol. All the 7 compounds had strong inhibition towards activity of Na＋,K＋-ATPase. With poisoning symptom exacerbating, the inhibition rates were gradually increased. In vitro, the IC50 of terpinen-4-ol, Z1, Z2, Z4, Z5, and Z6 was 155.89, 197.98, 96.02, 121.36, 124.85, and 153.74 μg mL% respectively. There was well correlation between the LDs0 of terpinen-4-ol derivatives to housefly and the IC50 of terpinen-4-ol derivatives to Na＋,K＋-ATPase in housefly. In conclusion, Na＋,K＋-ATPase was likely the target of terpinen-4-ol against insects.展开更多
To evaluate the toxicity against house fly Musca domestica L.(M. domestica)-larvicidal, pupicidal, and oviposition deterrent activities of essential oils(EOs) from five plants: Anethum graveolens L.(A. graveolens), Ce...To evaluate the toxicity against house fly Musca domestica L.(M. domestica)-larvicidal, pupicidal, and oviposition deterrent activities of essential oils(EOs) from five plants: Anethum graveolens L.(A. graveolens), Centratherum anthelminticum L.(C. anthelminticum), Foeniculum vulgare Mill.(F. vulgare), Pimpinella anisum L.(P. anisum), and Trachyspermum ammi L.(T. ammi) Sprague. Methods: Dipping, topical and dual-choice assays were performed by using each EO at three concentrations(1%, 5% and 10%) as well as cypermethrin(positive control) and ethyl alcohol(negative control) in order to determine their larvicidal, pupicidal and oviposition deterrent activities against M. domestica mortality rate and morphogenic abnormality of larvae and pupae were recorded after 3 and 10 days of incubation. Oviposition deterrent activity was recorded for 5 consecutive days from the beginning of the assay. Results: All EOs at the highest concentration(10%) were highly effective in oviposition deterrent with 100% effective repellency and an oviposition activity index of-1.00. Ten percent of F. vulgare oil exhibited the highest efficacy against the larvae with 89.6% mortality rate at 3 days and an LC50 value of 5.4%. Ten percent of A. graveolens and T. ammi oils showed the highest efficacy against the pupae with 100% mortality and an LC50 value ranging from 1.81%-2.24%. Conclusions: These results indicate that F. vulgare, A. graveolens and T. ammi EOs are effective larvicidal, pupicidal and oviposition deterrent agents against house fly M. domestica.展开更多
Antibacterial and antifungal peptides found in houseflies （Musca domestica） in large number are indispensable components of its immune defense mechanism. In this study the anterior tip of the larvae of housefly was ...Antibacterial and antifungal peptides found in houseflies （Musca domestica） in large number are indispensable components of its immune defense mechanism. In this study the anterior tip of the larvae of housefly was cut off with a pair of fine scissors and hemolymph was collected and exuded in an ice-cold test tube. From the hemolymph an antifungal substance was isolated by solid-phase extraction combined with reverse phase-high performance liquid chromotography （RP-HPLC） and named as Musca domestica antifungal peptide-1 （MAF-1）. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis （SDS-PAGE） showed its molecular weight was 17 kDa. UV absorption spectra revealed that this antifungal substance possessed the characteristics of protein peptides. Analysis by fingerprint-identification and tandem mass spectrometry suggested MAF-I was an unknown protein. Edman degradation identified the sequence of 30 amino acids of its N-terminal which matched no peptide in the MASCOT search database, indicating MAF-1 was a novel insect antifungal peptide. Mass spectrometry showed the precise molecular weight of MAF-1 was 17203.384 Da. Its isoelectric point was acidic.展开更多
Lysozymes can hydrolyze bacteria and play an important role in animal digestion and innate immunity. The cDNA of a chicken-type lysozyme gene （Mdlys） was cloned from housefly （Musca domestica）. The 484 bp full-len...Lysozymes can hydrolyze bacteria and play an important role in animal digestion and innate immunity. The cDNA of a chicken-type lysozyme gene （Mdlys） was cloned from housefly （Musca domestica）. The 484 bp full-length cDNA contains a 426 bp open reading frame （ORF） that encodes MdLys of 141 amino acids. Phylogenetic analysis indicated that the MdLys was similar to chicken-type lysozymes. Spatio-temporal expression of Mdlys was analyzed by RT-PCR. The Mdlys transcript can be detected in both midgut and fat body and was expressed at a relatively lower level at the embryo stage. Mdlys mRNA was upregulated 2 h post bacterial challenge, maintained for 2 to 6 h, and slightly declined from 12 to 24 h post-injection. Western blot analysis showed that MdLys was highly expressed in midgut and was also detected in the hemolymph and fat body. MdLys expression was slightly increased in midgut after challenging with Escherichia coli or Staphylococcus aureus. Its expression was also slightly increased in the fat body after challenging with S. aureus, but no obvious change occurred after E. coli challenge. MdLys expression in the hemolymph was not affected by bacterial challenge. In the developmental stages, MdLys expression levels had no obvious change from the first instar to the pupae stage. There was also no variation under 24 h starvation stress. Recombinant MdLys displayed inhibitory activity against Gram-negative and Gram-positive bacteria. Together, these results suggest that MdLys may play an important role in the innate immunity of houseflies.展开更多
The house fly, Musca domestica, has been implicated as a vector of Campy- lobacter spp., a major cause of human disease. Little is known whether house flies serve as biological amplifying hosts or mechanical vectors f...The house fly, Musca domestica, has been implicated as a vector of Campy- lobacter spp., a major cause of human disease. Little is known whether house flies serve as biological amplifying hosts or mechanical vectors for Campylobacterjejuni. We in- vestigated the period after C. jejuni had been ingested by house flies in which viable C. jejuni colonies could be isolated from whole bodies, the vomitus and the excreta of adult M. domestica and evaluated the activation of innate immune responses of house flies to ingested C. jejuni over time. C. jejuni could be cultured from infected houseflies soon after ingestion but no countable C. jejuni colonies were observed 〉 24 h postingestion. We detected viable C. jejuni in house fly vomitus and excreta up to 4 h after ingestion, but no viable bacteria were detected 〉 8 h. Suppression subtractive hybridization identi- fied pathogen-induced gene expression in the intestinal tracts of adult house flies 4-24 h after ingesting C. jejuni. We measured the expression of immune regulatory （thor, JNK, and spheroide） and effector （cecropin, diptericin, attacin, defensing, and lysozyme） genes in C. jejuni-infected and -uninfected house flies using quantitative real time PCR. Some house fly factor, or combination of factors, eliminates C. jejuni within 24 h postingestion. Because C. jejuni is not amplified within the body of the housefly, this insect likely serves as a mechanical vector rather than as a true biological, amplifying vector for C. jejuni, and adds to our understanding of insect pathogen interactions.展开更多
The ＂fly factor＂ was first discovered 〉60 years ago and describes the phe- nomenon that food currently or previously fed on by flies attracts more foraging flies than the same type and amount of food kept inaccessi...The ＂fly factor＂ was first discovered 〉60 years ago and describes the phe- nomenon that food currently or previously fed on by flies attracts more foraging flies than the same type and amount of food kept inaccessible to flies. Since then, there has been little progress made to understanding this phenomenon. Our objectives were （i） to demonstrate the existence of the fly factor in house flies, Musca domestica and （ii） to study underlying mechanisms that may cause or contribute to the fly factor. In 2-choice laboratory bioassays, we obtained unambiguous evidence for a fly factor phenomenon in house flies, in that we demonstrated that feeding flies are more attractive to foraging flies than are nonfeeding flies, and that fed-on food is more attractive to foraging flies than is ＂clean＂ food. Of the potential mechanisms （fly excreta, metabolic output parameters [elevated temperature, relative humidity, carbon dioxide]）, causing the fly factor, fly feces, and regurgitate do at- tract foraging flies but none of the metabolic output parameters of feeding flies does. Even though feeding flies produce significantly more CO2 than nonfeeding flies, elevated levels of CO2 have no behavior-modifying effect on flies. Preferential attraction of house flies to fly feces and regurgitate indicates that the flies sense airborne semiochemicals emana- ting from these sources. Hypothesizing that these semiochemicals are microbe-produced, future studies will aim at isolating and mass producing these microbes to accumulate semiochemicals for identification.展开更多
文摘Background: The occurrence of bacterial infections sometimes involves synanthropic flies and cockroaches, as mechanical vectors of pathogenic microorganisms. The aim of this study was to identify the different species of flies and cockroaches that cohabit with humans in the city of Cotonou and determine the contribution of Musca domestica and Periplaneta americana in the transmission of bacteria responsible for infections in humans. Methods: Capture sessions during the day for flies and at night for cockroaches were carried out in 4 arrondissements of the city of Cotonou. The insects collected were transported to the Center of Research Entomological of Cotonou for identification, then sent to the Section Hygiene of Water and Food for microbiological analysis, enumeration and testing for human pathogenic bacteria. Results: A total of 351 flies and 26 cockroaches were collected at the sites, including two synanthropic species belonging to two families each. Musca domestica and Periplaneta americana were the most abundant species found after identification in the city of Cotonou. Thermo-tolerant coliforms and Escherichia coli were found on all specimens at varying concentrations. Salmonella spp. bacteria were identified in the fly population from the Dantokpa dump. Conclusion: Flies and cockroaches can transmit microorganisms to humans. The presence of Salmonella spp. among the specimens revealed that infections frequently caused by contaminated food or water are also transmitted to humans by flies. The presence of these germs on flies and cockroaches represents a potential risk of mechanical transmission to humans. It is, therefore, essential to continue investigations in order to assess the species of bacteria propagated, improve control strategies against these troublesome insects and adopt better hygiene conditions for better living.
文摘The inhibition effect of chitooligosaccharides from housefly larvae on pathogens ofcrops seeds, fruits or vegetables was studied and the main factors influencing theantimicrobial activity of chitooligosaccharides were also investigated. It was foundthat chitooligosaccharides from housefly larvae had wide spectrum fungistasis. It canstrongly inhibit the development of 31 kinds of plant pathogenic fungi such as corticiumrolfsii Saccardo. The results indicated that the degree of deacelylation (DD) or theaverage molecular weight(MW)of chitooligosaccharides were related to the antimicrobialactivity. The antimicrobial activity increased with the rising of DD or the declining ofMW. Pot culture results showed that chitooligosaccharide could enhance the rate ofgermination and emergence of the seeds of maize, wheat and cotton. Chitooligosaccharidehad certain effect on corn southern leaf blight caused by Helminthosporium maydis.
基金supported by National Natural Science Foundation of China(No.81360254)National Sci-Tech Support Plan of China under grant(No.2011BAC06B12)the Science and Technology Program of Guizhou Province Agricultural research Project[No.NY(2014)3054]
文摘Objective To better comprehend the molecular structure and physiological function of the housefly larval peritrophic matrix （PM）, a mass spectrometry approach was used to investigate the PM protein composition. Methods The PM was dissected from the midgut of the third instar larvae, and protein extracted from the PM was evaluated using SDS-PAGE. A 1D-PAGE lane containing all protein bands was cut from top to bottom, the proteins in-gel trypsinised and analysed via shotgun liquid chromatography- tandem mass spectrometry （LC-MS/MS）. Results In total, 374 proteins, with molecular weights varying from 8.225, kD to 996.065 kD and isoelectric points ranging from 3.83 to 11.24 were successfully identified, most identified proteins were mainly related to immunity, digestion, nutrient metabolism and PM structure. Furthermore, many of these proteins were functionally associated with pattern binding, polysaccharide binding, structural constituent of peritrophic membrane and chitin binding, according to Gene Ontology annotation. Conclusion The PM protein composition, which provides a basis for further functional investigations of the identified proteins, will be useful for understanding the housefly larval gut immune system and may help to identify potential targets and exploit new bioinsecticides.
基金supported by the National Natural Science Foundation of China (30600404)
文摘To reveal the insecticidal mechanism of terpinen-4-ol, the activity of Na＋,K＋-ATPase in insects tested were determined in vivo and in vitro. The results showed that terpinen-4-ol and its ester derivatives had strong contact activity to housefly and the contact toxicities of its derivatives except Z3 were all superior or equivalent to terpinen-4-ol. All the 7 compounds had strong inhibition towards activity of Na＋,K＋-ATPase. With poisoning symptom exacerbating, the inhibition rates were gradually increased. In vitro, the IC50 of terpinen-4-ol, Z1, Z2, Z4, Z5, and Z6 was 155.89, 197.98, 96.02, 121.36, 124.85, and 153.74 μg mL% respectively. There was well correlation between the LDs0 of terpinen-4-ol derivatives to housefly and the IC50 of terpinen-4-ol derivatives to Na＋,K＋-ATPase in housefly. In conclusion, Na＋,K＋-ATPase was likely the target of terpinen-4-ol against insects.
基金supported by King Mongkut’s Institute of Technology Ladkrabang,Ladkrabang,Bangkok 10520,Thailand(Grant No.2560-01-04-001)The National Research Council of Thailand(Grant No.GRAD6006KMITL)
文摘To evaluate the toxicity against house fly Musca domestica L.(M. domestica)-larvicidal, pupicidal, and oviposition deterrent activities of essential oils(EOs) from five plants: Anethum graveolens L.(A. graveolens), Centratherum anthelminticum L.(C. anthelminticum), Foeniculum vulgare Mill.(F. vulgare), Pimpinella anisum L.(P. anisum), and Trachyspermum ammi L.(T. ammi) Sprague. Methods: Dipping, topical and dual-choice assays were performed by using each EO at three concentrations(1%, 5% and 10%) as well as cypermethrin(positive control) and ethyl alcohol(negative control) in order to determine their larvicidal, pupicidal and oviposition deterrent activities against M. domestica mortality rate and morphogenic abnormality of larvae and pupae were recorded after 3 and 10 days of incubation. Oviposition deterrent activity was recorded for 5 consecutive days from the beginning of the assay. Results: All EOs at the highest concentration(10%) were highly effective in oviposition deterrent with 100% effective repellency and an oviposition activity index of-1.00. Ten percent of F. vulgare oil exhibited the highest efficacy against the larvae with 89.6% mortality rate at 3 days and an LC50 value of 5.4%. Ten percent of A. graveolens and T. ammi oils showed the highest efficacy against the pupae with 100% mortality and an LC50 value ranging from 1.81%-2.24%. Conclusions: These results indicate that F. vulgare, A. graveolens and T. ammi EOs are effective larvicidal, pupicidal and oviposition deterrent agents against house fly M. domestica.
基金Acknowledgements This work was supported by grants from the National Natural Science Foundation of China （No. 39970087）, the Special Fund of Governor of Guizhou Province [QKJB（2003）04], and ＂Western Lights＂ of Chinese Academy of Sciences [KJWZ（2005）404].
文摘Antibacterial and antifungal peptides found in houseflies （Musca domestica） in large number are indispensable components of its immune defense mechanism. In this study the anterior tip of the larvae of housefly was cut off with a pair of fine scissors and hemolymph was collected and exuded in an ice-cold test tube. From the hemolymph an antifungal substance was isolated by solid-phase extraction combined with reverse phase-high performance liquid chromotography （RP-HPLC） and named as Musca domestica antifungal peptide-1 （MAF-1）. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis （SDS-PAGE） showed its molecular weight was 17 kDa. UV absorption spectra revealed that this antifungal substance possessed the characteristics of protein peptides. Analysis by fingerprint-identification and tandem mass spectrometry suggested MAF-I was an unknown protein. Edman degradation identified the sequence of 30 amino acids of its N-terminal which matched no peptide in the MASCOT search database, indicating MAF-1 was a novel insect antifungal peptide. Mass spectrometry showed the precise molecular weight of MAF-1 was 17203.384 Da. Its isoelectric point was acidic.
基金supported by the National High Technology Research and Development Program of China (863 Program) (No. 2007AA09Z425 and 2006AA100311)the Ph.D. Program Foundation of the Ministry of Education of China (No. 20060422034).
文摘Lysozymes can hydrolyze bacteria and play an important role in animal digestion and innate immunity. The cDNA of a chicken-type lysozyme gene （Mdlys） was cloned from housefly （Musca domestica）. The 484 bp full-length cDNA contains a 426 bp open reading frame （ORF） that encodes MdLys of 141 amino acids. Phylogenetic analysis indicated that the MdLys was similar to chicken-type lysozymes. Spatio-temporal expression of Mdlys was analyzed by RT-PCR. The Mdlys transcript can be detected in both midgut and fat body and was expressed at a relatively lower level at the embryo stage. Mdlys mRNA was upregulated 2 h post bacterial challenge, maintained for 2 to 6 h, and slightly declined from 12 to 24 h post-injection. Western blot analysis showed that MdLys was highly expressed in midgut and was also detected in the hemolymph and fat body. MdLys expression was slightly increased in midgut after challenging with Escherichia coli or Staphylococcus aureus. Its expression was also slightly increased in the fat body after challenging with S. aureus, but no obvious change occurred after E. coli challenge. MdLys expression in the hemolymph was not affected by bacterial challenge. In the developmental stages, MdLys expression levels had no obvious change from the first instar to the pupae stage. There was also no variation under 24 h starvation stress. Recombinant MdLys displayed inhibitory activity against Gram-negative and Gram-positive bacteria. Together, these results suggest that MdLys may play an important role in the innate immunity of houseflies.
文摘The house fly, Musca domestica, has been implicated as a vector of Campy- lobacter spp., a major cause of human disease. Little is known whether house flies serve as biological amplifying hosts or mechanical vectors for Campylobacterjejuni. We in- vestigated the period after C. jejuni had been ingested by house flies in which viable C. jejuni colonies could be isolated from whole bodies, the vomitus and the excreta of adult M. domestica and evaluated the activation of innate immune responses of house flies to ingested C. jejuni over time. C. jejuni could be cultured from infected houseflies soon after ingestion but no countable C. jejuni colonies were observed 〉 24 h postingestion. We detected viable C. jejuni in house fly vomitus and excreta up to 4 h after ingestion, but no viable bacteria were detected 〉 8 h. Suppression subtractive hybridization identi- fied pathogen-induced gene expression in the intestinal tracts of adult house flies 4-24 h after ingesting C. jejuni. We measured the expression of immune regulatory （thor, JNK, and spheroide） and effector （cecropin, diptericin, attacin, defensing, and lysozyme） genes in C. jejuni-infected and -uninfected house flies using quantitative real time PCR. Some house fly factor, or combination of factors, eliminates C. jejuni within 24 h postingestion. Because C. jejuni is not amplified within the body of the housefly, this insect likely serves as a mechanical vector rather than as a true biological, amplifying vector for C. jejuni, and adds to our understanding of insect pathogen interactions.
文摘The ＂fly factor＂ was first discovered 〉60 years ago and describes the phe- nomenon that food currently or previously fed on by flies attracts more foraging flies than the same type and amount of food kept inaccessible to flies. Since then, there has been little progress made to understanding this phenomenon. Our objectives were （i） to demonstrate the existence of the fly factor in house flies, Musca domestica and （ii） to study underlying mechanisms that may cause or contribute to the fly factor. In 2-choice laboratory bioassays, we obtained unambiguous evidence for a fly factor phenomenon in house flies, in that we demonstrated that feeding flies are more attractive to foraging flies than are nonfeeding flies, and that fed-on food is more attractive to foraging flies than is ＂clean＂ food. Of the potential mechanisms （fly excreta, metabolic output parameters [elevated temperature, relative humidity, carbon dioxide]）, causing the fly factor, fly feces, and regurgitate do at- tract foraging flies but none of the metabolic output parameters of feeding flies does. Even though feeding flies produce significantly more CO2 than nonfeeding flies, elevated levels of CO2 have no behavior-modifying effect on flies. Preferential attraction of house flies to fly feces and regurgitate indicates that the flies sense airborne semiochemicals emana- ting from these sources. Hypothesizing that these semiochemicals are microbe-produced, future studies will aim at isolating and mass producing these microbes to accumulate semiochemicals for identification.
