Objective:To investigate the effect of human contraceptive(HC) as ability to suppress the reproductive success of blow fly,Chrysomya megacephala(Fabricius)(C.megacephala) and offspring under controlled laboratory cond...Objective:To investigate the effect of human contraceptive(HC) as ability to suppress the reproductive success of blow fly,Chrysomya megacephala(Fabricius)(C.megacephala) and offspring under controlled laboratory conditions.Methods:Adult C.megacephala were fed with low(0.036 mg/mL) and high dose(0.072 mg/mL) HC(Microgest~?,Thailand),containing levonorgestrel and ethinyl estradiol,in their drinking water for 7 days.Three experiments were set;experimentⅠwith fed only in parental males,experimentⅡwith fed only in parental females and experimentⅢwith fed in both males and females.All experiments were then maintained for 3 generations after crossing and inbreeding.Results:A lower ovariole production and less fully mature ovarioles were evident in F1,F2 and F3 than control when parent males,females and both had been fed with high dose HC.Cellular changes during spermatogenesis in F1,F2 and F3 testes was confirmed using transmission electron microscopy(TEM),showing the low level of condensed chromatin,necrotic chromatin,irregularities and degenerated nuclear envelope in the nucleus. In the cytoplasm,mitochondrial swelling,rough endoplasmic reticulum swelling as well as vacuolated cytoplasm were noticed.As for the sperm per se,we found the degenerated nuclei and/ or incomplete mitochondrial derivative,axoneme and vacuolated flagella.Regarding deformity in F1,F2 and F3 ovariole,ultrastructural alteration observed by scanning electron microscopy (SEM) included malformations involving fragile enveloping peritoneal sheath,cracked ovarioles, peel away chorion,crumbled eggshell and incomplete development;whereas TEM presented malformed and disorganized mass of cells,proteic yolk granules and vacuolated vesicles. Conclusions:Administer of HC to adult C.megacephala caused ovariole reduction,less matured ovariole and affected cellular changes in testes and ovariole of offspring up to F3.展开更多
Samples of Chrysomya megacephala were collected from five sites in Malaysia, namely Penang, Selangor, Pahang, Johor, and Sabah. Molecular analysis was conducted using the cytochrome oxidase gene and ISSR-PCR to identi...Samples of Chrysomya megacephala were collected from five sites in Malaysia, namely Penang, Selangor, Pahang, Johor, and Sabah. Molecular analysis was conducted using the cytochrome oxidase gene and ISSR-PCR to identify polymorphic markers for distinguishing the populations and to estimate the genetic relatedness among these populations. Two SNPs were detected at sequence position 952 (M1) and 1120 (M2), involving transitional substitutions with cytosine (C) being replaced with thymine (T) and guanine (G) replaced with adenine (A), but there was no amino acid variation. Penang and Selangor shared the same nucleotide T at the M1 position, while M2 variation was found in Pahang population only. The NJ tree based on the COI sequence showed two main groups with branch A comprised of Penang and Selangor populations while branch B consisted of Johor, Pahang and Sabah populations. ISSR analysis indicated that 18 scorable bands (size 200 to 1800 bp) were amplified with UBC808 and UBC835, 11 bands of which were polymorphic and the rest monomorphic. Sabah population was left out for further analysis due to small number of specimens. UPGMA dendrogram using ISSR data showed two branches, one consisted of Penang and Selangor populations, while the other consisted of Pahang and Johor individuals. The polymorphic loci (P) for Johor Baru were 5.56%, Penang 16.70%, Selangor and Pahang 22.2%. Nei’s H values are respectively 0.018, 0.060, 0.050 and 0.051. Similarly the Shannon index diversity values are respectively 0.028, 0.089, 0.085 and 0.087. The lowest genetic distance (0.0997) was between Penang and Selangor populations, while the highest (0.613) was observed between Penang and Pahang populations. AMOVA shows low genetic differentiation among individuals within populations and that 85.6% of total genetic variance was among individuals between populations. This was also indicated by FST statistic of 0.8562. The gene flow between populations was low with Nm of 0.042, and Mantel’s test indicated a significant correlation between genetic distance and log geographic distance (P < 0.05 from 10,000 randomizations). In conclusion the Penang and Selangor fly populations are similar genetically, compared to the other populations.展开更多
The relationship between head pteridine fluorescence (HPF) levels and age in adult females and males of a common necrophagous fly, Chrysomya megacephala, and effects of temperature and fly sex on the relationship were...The relationship between head pteridine fluorescence (HPF) levels and age in adult females and males of a common necrophagous fly, Chrysomya megacephala, and effects of temperature and fly sex on the relationship were studied by pteridine fluorescence spectrophotometry. Factors affecting HPF levels in flies were found to include fly age, temperature and fly sex, among which the fly age was the most dominant one. There were significant linear relationships between HPF levels and age both for female and male adult flies at five constant temperatures, i. e. 16℃, 20℃, 24℃, 28℃ and 32℃. The relationship between mean rate of pteridine accumulation (FV or MV) and temperature(t)could be well described by a modified exponential equation of FV0.01288×e (0.2241t-3.127)+0.3649 (r20.9987) for females and a linear regression equation of MV0.0574 t-0.3637 (r20.9557) for males. Using the information from the experiments at five constant temperatures, three calculated methods as the candidates were developed for accurately determining the age of the fly by HPF levels at ambient temperature. The results revealed that these three methods were suitable for estimating the age only for male flies, but not for female flies. The smallest average error of the predicated age was 2.55 days for males. In addition, how to employ which of these three developed methods for determining ages of male flies in practical was also discussed.展开更多
Chrysomya megacephala (Fabricius,1794) occurs on every continent and is closely associated with carrion and decaying material in human environments.Its abilities to find dead bodies and carry pathogens give it a promi...Chrysomya megacephala (Fabricius,1794) occurs on every continent and is closely associated with carrion and decaying material in human environments.Its abilities to find dead bodies and carry pathogens give it a prominence in human affairs that may involve prosecution or litigation,and therefore forensic entomologists.The identification,geographical distribution and biology of the species are reviewed to provide a background for approaches that four branches of forensic entomology (urban,stored-product,medico-criminal and environmental) might take to investigations involving this fly.展开更多
Nodulation is the predominant cellular defense reaction to bacterial challenges in insects. In this study, third instar larvae of Chrysomya megacephala were injected with bacteria, Escherichia coli K 12 （10^6 CFU/mL...Nodulation is the predominant cellular defense reaction to bacterial challenges in insects. In this study, third instar larvae of Chrysomya megacephala were injected with bacteria, Escherichia coli K 12 （10^6 CFU/mL, 2μL）, immediately prior to injection of inhibitors of eicosanoid biosynthesis, which sharply reduced nodulation response. Test larvae were treated with specific inhibitors ofphospholipase A2 （dexamethasone）, cyclo- oxygenase （indomethacin, ibuprofen and piroxicam）, dual cyclo-oxygenase/lipoxygenase （phenidone） and lipoxygenase （esculetin） and these reduced nodulation except esculetin. The influence of bacteria was obvious within 2 h of injection （5 nodules/larva）, and increased to a maximum after 8 h （with 15 nodules/larva）, and then significantly reduced over 24 h （9 nodules/larva）. The inhibitory influence of dexamethasone was apparent within 2 h of injection （4 vs. 5 nodules/larva）, and nodulation was significantly reduced, compared to control, over 24 h （5 vs. 8 nodules/larva）. Increased dosages of ibuprofen, indomethacin, piroxicam and phenidone led to decreased numbers of nodules. Nodules continued to exist during the pupal stage. However, the effects of dexamethasone were reversed by treating bacteria-injected insects with an eicosanoid-precursor polyunsaturated fatty acid, arachidonic acid. These findings approved our view that eicosanoid can mediate cellular defense mechanisms in response to bacterial infections in another Dipteran insect C. rnegacephala.展开更多
基金Suported by Thailand Research Fund and the Royal Golden Jubilee Ph.D.Program(PHD/0113/2547)
文摘Objective:To investigate the effect of human contraceptive(HC) as ability to suppress the reproductive success of blow fly,Chrysomya megacephala(Fabricius)(C.megacephala) and offspring under controlled laboratory conditions.Methods:Adult C.megacephala were fed with low(0.036 mg/mL) and high dose(0.072 mg/mL) HC(Microgest~?,Thailand),containing levonorgestrel and ethinyl estradiol,in their drinking water for 7 days.Three experiments were set;experimentⅠwith fed only in parental males,experimentⅡwith fed only in parental females and experimentⅢwith fed in both males and females.All experiments were then maintained for 3 generations after crossing and inbreeding.Results:A lower ovariole production and less fully mature ovarioles were evident in F1,F2 and F3 than control when parent males,females and both had been fed with high dose HC.Cellular changes during spermatogenesis in F1,F2 and F3 testes was confirmed using transmission electron microscopy(TEM),showing the low level of condensed chromatin,necrotic chromatin,irregularities and degenerated nuclear envelope in the nucleus. In the cytoplasm,mitochondrial swelling,rough endoplasmic reticulum swelling as well as vacuolated cytoplasm were noticed.As for the sperm per se,we found the degenerated nuclei and/ or incomplete mitochondrial derivative,axoneme and vacuolated flagella.Regarding deformity in F1,F2 and F3 ovariole,ultrastructural alteration observed by scanning electron microscopy (SEM) included malformations involving fragile enveloping peritoneal sheath,cracked ovarioles, peel away chorion,crumbled eggshell and incomplete development;whereas TEM presented malformed and disorganized mass of cells,proteic yolk granules and vacuolated vesicles. Conclusions:Administer of HC to adult C.megacephala caused ovariole reduction,less matured ovariole and affected cellular changes in testes and ovariole of offspring up to F3.
文摘Samples of Chrysomya megacephala were collected from five sites in Malaysia, namely Penang, Selangor, Pahang, Johor, and Sabah. Molecular analysis was conducted using the cytochrome oxidase gene and ISSR-PCR to identify polymorphic markers for distinguishing the populations and to estimate the genetic relatedness among these populations. Two SNPs were detected at sequence position 952 (M1) and 1120 (M2), involving transitional substitutions with cytosine (C) being replaced with thymine (T) and guanine (G) replaced with adenine (A), but there was no amino acid variation. Penang and Selangor shared the same nucleotide T at the M1 position, while M2 variation was found in Pahang population only. The NJ tree based on the COI sequence showed two main groups with branch A comprised of Penang and Selangor populations while branch B consisted of Johor, Pahang and Sabah populations. ISSR analysis indicated that 18 scorable bands (size 200 to 1800 bp) were amplified with UBC808 and UBC835, 11 bands of which were polymorphic and the rest monomorphic. Sabah population was left out for further analysis due to small number of specimens. UPGMA dendrogram using ISSR data showed two branches, one consisted of Penang and Selangor populations, while the other consisted of Pahang and Johor individuals. The polymorphic loci (P) for Johor Baru were 5.56%, Penang 16.70%, Selangor and Pahang 22.2%. Nei’s H values are respectively 0.018, 0.060, 0.050 and 0.051. Similarly the Shannon index diversity values are respectively 0.028, 0.089, 0.085 and 0.087. The lowest genetic distance (0.0997) was between Penang and Selangor populations, while the highest (0.613) was observed between Penang and Pahang populations. AMOVA shows low genetic differentiation among individuals within populations and that 85.6% of total genetic variance was among individuals between populations. This was also indicated by FST statistic of 0.8562. The gene flow between populations was low with Nm of 0.042, and Mantel’s test indicated a significant correlation between genetic distance and log geographic distance (P < 0.05 from 10,000 randomizations). In conclusion the Penang and Selangor fly populations are similar genetically, compared to the other populations.
文摘The relationship between head pteridine fluorescence (HPF) levels and age in adult females and males of a common necrophagous fly, Chrysomya megacephala, and effects of temperature and fly sex on the relationship were studied by pteridine fluorescence spectrophotometry. Factors affecting HPF levels in flies were found to include fly age, temperature and fly sex, among which the fly age was the most dominant one. There were significant linear relationships between HPF levels and age both for female and male adult flies at five constant temperatures, i. e. 16℃, 20℃, 24℃, 28℃ and 32℃. The relationship between mean rate of pteridine accumulation (FV or MV) and temperature(t)could be well described by a modified exponential equation of FV0.01288×e (0.2241t-3.127)+0.3649 (r20.9987) for females and a linear regression equation of MV0.0574 t-0.3637 (r20.9557) for males. Using the information from the experiments at five constant temperatures, three calculated methods as the candidates were developed for accurately determining the age of the fly by HPF levels at ambient temperature. The results revealed that these three methods were suitable for estimating the age only for male flies, but not for female flies. The smallest average error of the predicated age was 2.55 days for males. In addition, how to employ which of these three developed methods for determining ages of male flies in practical was also discussed.
文摘Chrysomya megacephala (Fabricius,1794) occurs on every continent and is closely associated with carrion and decaying material in human environments.Its abilities to find dead bodies and carry pathogens give it a prominence in human affairs that may involve prosecution or litigation,and therefore forensic entomologists.The identification,geographical distribution and biology of the species are reviewed to provide a background for approaches that four branches of forensic entomology (urban,stored-product,medico-criminal and environmental) might take to investigations involving this fly.
文摘Nodulation is the predominant cellular defense reaction to bacterial challenges in insects. In this study, third instar larvae of Chrysomya megacephala were injected with bacteria, Escherichia coli K 12 （10^6 CFU/mL, 2μL）, immediately prior to injection of inhibitors of eicosanoid biosynthesis, which sharply reduced nodulation response. Test larvae were treated with specific inhibitors ofphospholipase A2 （dexamethasone）, cyclo- oxygenase （indomethacin, ibuprofen and piroxicam）, dual cyclo-oxygenase/lipoxygenase （phenidone） and lipoxygenase （esculetin） and these reduced nodulation except esculetin. The influence of bacteria was obvious within 2 h of injection （5 nodules/larva）, and increased to a maximum after 8 h （with 15 nodules/larva）, and then significantly reduced over 24 h （9 nodules/larva）. The inhibitory influence of dexamethasone was apparent within 2 h of injection （4 vs. 5 nodules/larva）, and nodulation was significantly reduced, compared to control, over 24 h （5 vs. 8 nodules/larva）. Increased dosages of ibuprofen, indomethacin, piroxicam and phenidone led to decreased numbers of nodules. Nodules continued to exist during the pupal stage. However, the effects of dexamethasone were reversed by treating bacteria-injected insects with an eicosanoid-precursor polyunsaturated fatty acid, arachidonic acid. These findings approved our view that eicosanoid can mediate cellular defense mechanisms in response to bacterial infections in another Dipteran insect C. rnegacephala.
