In order to understand the composition and quantitative variation of ecdysteriods in the adults and eggs of Opogona sacchari (Bojer), an invasive alien pest, we analyzed the ecdysteroid composition and titers in the a...In order to understand the composition and quantitative variation of ecdysteriods in the adults and eggs of Opogona sacchari (Bojer), an invasive alien pest, we analyzed the ecdysteroid composition and titers in the adult and egg of this pest. On day 4 after eclosion, the titer of ecdysteriods in the male adult was 0.080 ng/adult, much lower than 5.978 ng/adult in the female adult. During the development of ovaries, the titer of ecdysteriods was low on the first two days, and high in the late period, with the peak (10.48 ng/ovary) appearing on day 3. During the development of eggs, the titer of ecdysteriods was about 0.010 ng/egg from day 1 to day 3, and then decreased to 0.006 ng/egg on day 4. In both adults and eggs, three main components of ecdysteriods were found by identification of HPLC/RIA. They were 20-hydroxyecdysone, 26-hydroxyecdysone, and an unidentified component.展开更多
One new ecdysteroid, (24 R ) 24 (2 hydroxyethyl) 20 hydroxyecdysone (3), as well as three known ecdysteroids, has been isolated from Chinese herb Serratula strangulata and these compounds 1-4 showed effecti...One new ecdysteroid, (24 R ) 24 (2 hydroxyethyl) 20 hydroxyecdysone (3), as well as three known ecdysteroids, has been isolated from Chinese herb Serratula strangulata and these compounds 1-4 showed effective antioxidant activity on AAPH induced hemolysis of human RBC and Fe 2+ + cysteine induced lipid peroxidation of liver microsome.展开更多
We present the results of eyestalk extirpation experiments performed on the fiddler crab, Uca triangularis at seasons of molting and reproduction, with a view to have a better understanding of the regulatory mechanism...We present the results of eyestalk extirpation experiments performed on the fiddler crab, Uca triangularis at seasons of molting and reproduction, with a view to have a better understanding of the regulatory mechanisms of these two highly energy-demanding processes. Bilateral eyestalk ablation resulted in precocious acceleration of both molting and reproduction, irrespective of the season at which each experiment was conducted. The rate of accelerated ovarian growth, however, was maximum if the eyestalk ablation was conducted during August-January, the breeding season in the wild, or in February- May （molting-reproductive season）, wherein a section of the wild population would be engaged in molting and another section in breeding. The highest degree of precocious molt acceleration, on the other hand, was obtained during June-July when the population was primarily engaged in molting, but with no reproductive activity. The precocious oocyte maturation （due to de-eyestalking） was minimal in June--July. Significantly, the eyestalk ablation also resulted in a dramatic increase in the hemolymph ecdysteroid titer, revealing that a high ecdysteroid titer would have no restraining influence on vitellogenesis. No spawning was, however, observed among de-eyestalked females, even though their final oocyte size surpassed the size of the normal mature oocytes, implying that spawning is not exclusively under the control of eyestalk hormones. A comparative study performed on the viteUine components of the experimentals and the controls revealed that the precociously incorporated yolk under eyestalk ablation was biochemically impoverished. These results indicate that throughout the annual cycle, both the somatic and the reproductive growth of U. triangularis are under the influence of inhibitory principles from the eyestalks. It is also revealing that mere deprival of the inhibitory principles does not culminate into successful vitellogenesis. Arguably, the inhibitory influence from the eyestalks could be a prerequisite for normal healthy maturation of the oocytes and spawning.展开更多
The large life cycle Rhaponticum integrifolium in natural populations (Qashqadaryo, Uzbekistan) was studied. Duration of before generative, generative and senile periods of Rhaponticum integrifolium is 2 - 5, 8 - 10 a...The large life cycle Rhaponticum integrifolium in natural populations (Qashqadaryo, Uzbekistan) was studied. Duration of before generative, generative and senile periods of Rhaponticum integrifolium is 2 - 5, 8 - 10 and 2 - 4 years respectively. The beginning of phenophases depends on the height of the terrain above sea level: raising the terrain from 400 to 1500 m leads to a delay in the onset of phenophases. Age states of Rhaponticum integrifolium in different ecological and phytogenetic conditions were revealed. Updated distribution of detected participation of vegetation and the raw Rhaponticum integrifolium in Uzbekistan, describes the dynamics of the contents ecdysteroids in the periods of vegetation. At the same time, a map of the species area in Central Asia was made and the term of its phytomass recovery under different operating modes of thickets was determined.展开更多
Ajuga Turkestanica, an herbaceous flowering species in the mint family, has been traditionally used in Turkeyand Uzbekistan for heart disease, muscle aches and stomach problems. Due to its high levels of phytoecdyster...Ajuga Turkestanica, an herbaceous flowering species in the mint family, has been traditionally used in Turkeyand Uzbekistan for heart disease, muscle aches and stomach problems. Due to its high levels of phytoecdysteroids (particularly the characteristic C-11-hydroxylated Turkesterone), anabolic properties have also been reported. The aim of our study was to screen for early signs of efficacy and safety of a proprietary Ajuga turkestanica extract (ATE) using in vitro models. C2C12 mouse myotube cell line was used to study potential effects on viability and gene modulation. Cell viability was evaluated with different concentrations [0.2 - 200 ppm (mg/L)] of ATE. Gene modulation was assessed by quantitative polymerase chain reaction (qRT-PCR) after 6h incubation (ATE vs. the androgenic anabolic steroid methandrostenolone). Total androgenic activity was measured using the A-SCREEN bioassay. Ultra-high performance liquid chromatography analysis showed good correlation between the phytochemical profile of the native plant and our ATE. C2C12 mouse myotube cells treated with ATE experienced no significant loss of viability (concentrations 0.2 - 200 ppm, 1 - 24 hs, p > 0.05). qRT-PCR array analysis showed significant (p regulation of Caspase-3 (2-fold) and Myostatin (4-fold). The extract showed no androgenic activity within the dose range used. Our results indicate the potential for an ATE to support muscle mass without typical androgenic side effects of synthetic anabolic drugs.展开更多
Objective:To investigate the anti-proliferative effects of 20-hydroxyecdysone isolated from the bark of Dacrycarpus imbricatus(Blume)de Laub.Methods:Column chromatography was used for isolation of compounds from plant...Objective:To investigate the anti-proliferative effects of 20-hydroxyecdysone isolated from the bark of Dacrycarpus imbricatus(Blume)de Laub.Methods:Column chromatography was used for isolation of compounds from plant material.The structure of the isolated compound was identified by mass spectrometry and nuclear magnetic resonance techniques,including HSQC,HMBC,NOE-difference experiments.The isolated compound was tested for its anti-proliferative activity in acute myeloid leukemia(AML)and OCI-AML cells.Results:Compound 1 was isolated from the ethyl acetate fraction of Dacrycarpus imbricatus barks by column chromatography.Its chemical structure was identified as 20-hydroxyecdysone(20HE),a cholestane-type ecdysteroid,by a combination of mass spectrometry and nuclear magnetic resonance spectrometric analyses.Our goal was to test the anti-proliferative activity of 20 HE using the OCI-AML cell line.20 HE significantly decreased OCI cell number at a concentration of 1 mg/mL,whereas lower concentrations were ineffective.Moreover,this decrease was due to partial blockage of the G_1/S phase of the cell cycle,with a reduction of cells in the G_2M phase,not due to increased apoptosis.Conclusions:This indicates that 20 HE significantly decreases the number of cells in the G_1/S phase of the cell cycle in human AML cells.This is the first time that the anti-proliferative activity of 20 HE against a human tumor cell line has been reported.展开更多
This paper describes the embryonic development of the common cutworm Spodoptera litura （Fabricius） （Lepidoptera： Noctuidae） which is divided into eight embryonic stages, through variations in the egg＇s contents....This paper describes the embryonic development of the common cutworm Spodoptera litura （Fabricius） （Lepidoptera： Noctuidae） which is divided into eight embryonic stages, through variations in the egg＇s contents. Experiments were conducted on the eggs ofS. litura under laboratory conditions. The highest concentration of the protein （min.-max.： 32-! 40 lag/egg） and the lowest of the carbohydrate （min.-max.： 3.0-44.0 lag/egg） were obtained; similarly, the DNA content was smaller （min.-max.： 1.0-38.2 lag/egg） than the RNA （min.-max.： 9.2-360.0 lag/egg） throughout the embryogenesis. Three peaks of ecdysteroid titre were observed which were responsible for appearance of particular events during embryogenesis. The last highest peak of 400_＋33.4 lag/egg was appeared at 84 h after oviposition when larva was ready to hatch. Therefore, it is concluded that eight embryonic stages in S. litura were characterized by fluctuation in the egg＇s contents, which were responsible for gradual-progressive embryonic development. The egg-larval development did not show a normal distribution of embryonic developmental-time.展开更多
This paper describes effects of sublethal-doses of chlorfluazuron on morphology of embryogenesis when LD10 （1.00 ng/larva） or LD30 （3.75 ng/larva） was applied topically to newly-ecdysed fifth-instars of common cut...This paper describes effects of sublethal-doses of chlorfluazuron on morphology of embryogenesis when LD10 （1.00 ng/larva） or LD30 （3.75 ng/larva） was applied topically to newly-ecdysed fifth-instars of common cutworm, Spodoptera litura F.. Experiments were conducted on eggs of F1 generation laid by subsequent adults under laboratory conditions. Fecundity was significantly reduced by LD10 and more significantly reduced by LD30 compared with untreated females. Number of unfertilized-unhatched-eggs was not significantly affected by the treatments, Fertilized eggs revealed changes in external coloration of eggs. Embryonic development of S. litura was divided into eight embryonic stages. During stage 5 （12-16 h after oviposition）, in LD10-treated-egg, crescent-shaped-embryo was affectedly differentiated. During the same stage, it was seriously affected in LD30-treated-egg. During stage 7 （32-64 h after oviposition）, in LD10-treated-egg, organogenesis was established, but body structures were affectedly developed. In LD30-treated-egg, body structures were more affectedly developed during the same stage. It is concluded that embryonic developmental stages were affected by LD10 and more seriously affected by LD30. The effects of residualchlorfluazuron on embryogenesis are thought to be one of the factors responsible for the reduction in fertility and hatchability caused by sublethal doses of chlorfluazuron in S. litura.展开更多
Effects of ecdysteroid and juvenile hormone (JH) on vitellogenesis of the Japanese oak silkworm, Antheraea yamamai are reported in this article. After topical treatment with 20 hydroxyecdysone alone or JH analog ...Effects of ecdysteroid and juvenile hormone (JH) on vitellogenesis of the Japanese oak silkworm, Antheraea yamamai are reported in this article. After topical treatment with 20 hydroxyecdysone alone or JH analog (i.e. methoprene) alone and combined treatment with these two chemicals, vitellogenin (Vg) titers in the fat body and haemolymph at the pupal stage were mostly higher than those of the control, indicating that both ecdysteroid and JH exerted a promoting effect on the synthesis of Vg. In contrast, the Vg uptake was markedly inhibited by JH while stimulating effect of the ecdysteroid could be shown that vitellin (Vt) titer in the ovary was lower after methoprene treatments, but higher after 20 hydroxyecdyson treatments. Meanwhile, effects of these two hormones on Vg synthesis in the fat body were also tested with the incubation in vitro with Grace medium containing 3H leucine and the hormones. The results demonstrated that Vg synthesis was stimulated after treating with methoprene alone or 20 hydroxyecdysone alone and combined treating with these two chemicals, and particularly ecdysteroid had more marked positive effect. To comprehensively concluded our results, it could be regarded that ecdysteroid play the main role in the regulation of vitellogenesis for the Japanese oak silkworm.展开更多
Developmental changes in hemolymph ecdysteroid level, ecdysteroid synthesis by prothoracic glands （PGs） in vitro, prothoracicotropic hormone （PTTH） activity in brain extracts, and PTTH activity in the hemolymph we...Developmental changes in hemolymph ecdysteroid level, ecdysteroid synthesis by prothoracic glands （PGs） in vitro, prothoracicotropic hormone （PTTH） activity in brain extracts, and PTTH activity in the hemolymph were measured during the fifth larval instar of the Eri silkworm, Samia cynthia ricini. The changing patterns of hemolymph ecdysteroid level and ecdysteroid synthesis by laGs in vitro are similar to each other, with maximums on day 9. However, on this day, hemolymph ecdysteroid level was substantially higher than ecdysteroid synthesis by PGs in vitro suggesting a high PTTH activity in the hemolymph on day 9. Moreover, the changing pattern of PTTH activity in brain extracts is also similar to that of PTTH activity in the hemolymph, both peaking on day 9. However, on this day, activity in brain extracts was much smaller than PTTH activity in the hemolymph implying that most PTTH synthesized by the brain is secreted to the hemolymph and the brain stores a very little amount of PTTH. This study provides unique insights onto the hormonal regulation of ecdysteroid synthesis in the Eri silkworm and is useful for our future studies on signal transduction of insect neurolaelatides.展开更多
Insect neuropeptides regulate various physiological processes,such as reproduction,feeding,growth and development,and have been considered as viable targets in the development of alternative strategies for pest contro...Insect neuropeptides regulate various physiological processes,such as reproduction,feeding,growth and development,and have been considered as viable targets in the development of alternative strategies for pest control.Amongst these neuropeptides is myosuppressin(MS),a very conserved neuropeptide that has been reported to regulate cardiac and skeletal muscle contractility,feeding and pupal diapause in insects.In this study,we investigated the involvement of MS in fecundity in a notorious defoliator of potato and other solanaceous plants,the Colorado potato beetle(CPB),Leptinotarsa decemlineata.We identified an MS-precursor-encoding transcript in the L.decemlineata transcriptomic database and then evaluated its transcript levels in various CPB tissues.MS transcript levels were found to be highest in the central nervous system,gut and muscle of CPB males and females.To investigate the role of MS in fecundity,MS was silenced in adult CPBs through RNA interference(RNAi).This resulted in a significant reduction in oviposition(over 80%)and oocyte size(69%)in the treated beetles compared to the controls.Also,the reduction in oviposition in treated females was confirmed to be dependent on MS knockdown and independent of male fertilization.Furthermore,MS-knockdown in females resulted in decreased levels of ecdysteroid hormone titers and the transcript levels of its receptor.Interestingly,the injection of 20-hydroxyecdysone into females following MS knockdown could rescue ovary development.Altogether,this study highlights the important role played by MS in regulating fecundity in CPB.展开更多
基金the National Natural Science Foundation of China (Grant No. 39870476)the Natural Science Foundation of Guangdong Province (Grant Nos. E039254 and 031626)the Scientific and Technological Plan of Zhuhai City (Grant No. PC20051046)
文摘In order to understand the composition and quantitative variation of ecdysteriods in the adults and eggs of Opogona sacchari (Bojer), an invasive alien pest, we analyzed the ecdysteroid composition and titers in the adult and egg of this pest. On day 4 after eclosion, the titer of ecdysteriods in the male adult was 0.080 ng/adult, much lower than 5.978 ng/adult in the female adult. During the development of ovaries, the titer of ecdysteriods was low on the first two days, and high in the late period, with the peak (10.48 ng/ovary) appearing on day 3. During the development of eggs, the titer of ecdysteriods was about 0.010 ng/egg from day 1 to day 3, and then decreased to 0.006 ng/egg on day 4. In both adults and eggs, three main components of ecdysteriods were found by identification of HPLC/RIA. They were 20-hydroxyecdysone, 26-hydroxyecdysone, and an unidentified component.
文摘One new ecdysteroid, (24 R ) 24 (2 hydroxyethyl) 20 hydroxyecdysone (3), as well as three known ecdysteroids, has been isolated from Chinese herb Serratula strangulata and these compounds 1-4 showed effective antioxidant activity on AAPH induced hemolysis of human RBC and Fe 2+ + cysteine induced lipid peroxidation of liver microsome.
基金Supported by the International Foundation for Science(Stockholm,Sweden)(RGA:A/3520-1)the Junior Research Fellowship,Kannur University
文摘We present the results of eyestalk extirpation experiments performed on the fiddler crab, Uca triangularis at seasons of molting and reproduction, with a view to have a better understanding of the regulatory mechanisms of these two highly energy-demanding processes. Bilateral eyestalk ablation resulted in precocious acceleration of both molting and reproduction, irrespective of the season at which each experiment was conducted. The rate of accelerated ovarian growth, however, was maximum if the eyestalk ablation was conducted during August-January, the breeding season in the wild, or in February- May （molting-reproductive season）, wherein a section of the wild population would be engaged in molting and another section in breeding. The highest degree of precocious molt acceleration, on the other hand, was obtained during June-July when the population was primarily engaged in molting, but with no reproductive activity. The precocious oocyte maturation （due to de-eyestalking） was minimal in June--July. Significantly, the eyestalk ablation also resulted in a dramatic increase in the hemolymph ecdysteroid titer, revealing that a high ecdysteroid titer would have no restraining influence on vitellogenesis. No spawning was, however, observed among de-eyestalked females, even though their final oocyte size surpassed the size of the normal mature oocytes, implying that spawning is not exclusively under the control of eyestalk hormones. A comparative study performed on the viteUine components of the experimentals and the controls revealed that the precociously incorporated yolk under eyestalk ablation was biochemically impoverished. These results indicate that throughout the annual cycle, both the somatic and the reproductive growth of U. triangularis are under the influence of inhibitory principles from the eyestalks. It is also revealing that mere deprival of the inhibitory principles does not culminate into successful vitellogenesis. Arguably, the inhibitory influence from the eyestalks could be a prerequisite for normal healthy maturation of the oocytes and spawning.
文摘The large life cycle Rhaponticum integrifolium in natural populations (Qashqadaryo, Uzbekistan) was studied. Duration of before generative, generative and senile periods of Rhaponticum integrifolium is 2 - 5, 8 - 10 and 2 - 4 years respectively. The beginning of phenophases depends on the height of the terrain above sea level: raising the terrain from 400 to 1500 m leads to a delay in the onset of phenophases. Age states of Rhaponticum integrifolium in different ecological and phytogenetic conditions were revealed. Updated distribution of detected participation of vegetation and the raw Rhaponticum integrifolium in Uzbekistan, describes the dynamics of the contents ecdysteroids in the periods of vegetation. At the same time, a map of the species area in Central Asia was made and the term of its phytomass recovery under different operating modes of thickets was determined.
文摘Ajuga Turkestanica, an herbaceous flowering species in the mint family, has been traditionally used in Turkeyand Uzbekistan for heart disease, muscle aches and stomach problems. Due to its high levels of phytoecdysteroids (particularly the characteristic C-11-hydroxylated Turkesterone), anabolic properties have also been reported. The aim of our study was to screen for early signs of efficacy and safety of a proprietary Ajuga turkestanica extract (ATE) using in vitro models. C2C12 mouse myotube cell line was used to study potential effects on viability and gene modulation. Cell viability was evaluated with different concentrations [0.2 - 200 ppm (mg/L)] of ATE. Gene modulation was assessed by quantitative polymerase chain reaction (qRT-PCR) after 6h incubation (ATE vs. the androgenic anabolic steroid methandrostenolone). Total androgenic activity was measured using the A-SCREEN bioassay. Ultra-high performance liquid chromatography analysis showed good correlation between the phytochemical profile of the native plant and our ATE. C2C12 mouse myotube cells treated with ATE experienced no significant loss of viability (concentrations 0.2 - 200 ppm, 1 - 24 hs, p > 0.05). qRT-PCR array analysis showed significant (p regulation of Caspase-3 (2-fold) and Myostatin (4-fold). The extract showed no androgenic activity within the dose range used. Our results indicate the potential for an ATE to support muscle mass without typical androgenic side effects of synthetic anabolic drugs.
基金the National Foundation for Science&Technology Development(NAFOSTED)of Vietnam for financial support of this research(code:104.01-2013.62)the Italian Ministery of Foreign Affairs and International Cooperation(MAECI)
文摘Objective:To investigate the anti-proliferative effects of 20-hydroxyecdysone isolated from the bark of Dacrycarpus imbricatus(Blume)de Laub.Methods:Column chromatography was used for isolation of compounds from plant material.The structure of the isolated compound was identified by mass spectrometry and nuclear magnetic resonance techniques,including HSQC,HMBC,NOE-difference experiments.The isolated compound was tested for its anti-proliferative activity in acute myeloid leukemia(AML)and OCI-AML cells.Results:Compound 1 was isolated from the ethyl acetate fraction of Dacrycarpus imbricatus barks by column chromatography.Its chemical structure was identified as 20-hydroxyecdysone(20HE),a cholestane-type ecdysteroid,by a combination of mass spectrometry and nuclear magnetic resonance spectrometric analyses.Our goal was to test the anti-proliferative activity of 20 HE using the OCI-AML cell line.20 HE significantly decreased OCI cell number at a concentration of 1 mg/mL,whereas lower concentrations were ineffective.Moreover,this decrease was due to partial blockage of the G_1/S phase of the cell cycle,with a reduction of cells in the G_2M phase,not due to increased apoptosis.Conclusions:This indicates that 20 HE significantly decreases the number of cells in the G_1/S phase of the cell cycle in human AML cells.This is the first time that the anti-proliferative activity of 20 HE against a human tumor cell line has been reported.
文摘This paper describes the embryonic development of the common cutworm Spodoptera litura （Fabricius） （Lepidoptera： Noctuidae） which is divided into eight embryonic stages, through variations in the egg＇s contents. Experiments were conducted on the eggs ofS. litura under laboratory conditions. The highest concentration of the protein （min.-max.： 32-! 40 lag/egg） and the lowest of the carbohydrate （min.-max.： 3.0-44.0 lag/egg） were obtained; similarly, the DNA content was smaller （min.-max.： 1.0-38.2 lag/egg） than the RNA （min.-max.： 9.2-360.0 lag/egg） throughout the embryogenesis. Three peaks of ecdysteroid titre were observed which were responsible for appearance of particular events during embryogenesis. The last highest peak of 400_＋33.4 lag/egg was appeared at 84 h after oviposition when larva was ready to hatch. Therefore, it is concluded that eight embryonic stages in S. litura were characterized by fluctuation in the egg＇s contents, which were responsible for gradual-progressive embryonic development. The egg-larval development did not show a normal distribution of embryonic developmental-time.
文摘This paper describes effects of sublethal-doses of chlorfluazuron on morphology of embryogenesis when LD10 （1.00 ng/larva） or LD30 （3.75 ng/larva） was applied topically to newly-ecdysed fifth-instars of common cutworm, Spodoptera litura F.. Experiments were conducted on eggs of F1 generation laid by subsequent adults under laboratory conditions. Fecundity was significantly reduced by LD10 and more significantly reduced by LD30 compared with untreated females. Number of unfertilized-unhatched-eggs was not significantly affected by the treatments, Fertilized eggs revealed changes in external coloration of eggs. Embryonic development of S. litura was divided into eight embryonic stages. During stage 5 （12-16 h after oviposition）, in LD10-treated-egg, crescent-shaped-embryo was affectedly differentiated. During the same stage, it was seriously affected in LD30-treated-egg. During stage 7 （32-64 h after oviposition）, in LD10-treated-egg, organogenesis was established, but body structures were affectedly developed. In LD30-treated-egg, body structures were more affectedly developed during the same stage. It is concluded that embryonic developmental stages were affected by LD10 and more seriously affected by LD30. The effects of residualchlorfluazuron on embryogenesis are thought to be one of the factors responsible for the reduction in fertility and hatchability caused by sublethal doses of chlorfluazuron in S. litura.
文摘Effects of ecdysteroid and juvenile hormone (JH) on vitellogenesis of the Japanese oak silkworm, Antheraea yamamai are reported in this article. After topical treatment with 20 hydroxyecdysone alone or JH analog (i.e. methoprene) alone and combined treatment with these two chemicals, vitellogenin (Vg) titers in the fat body and haemolymph at the pupal stage were mostly higher than those of the control, indicating that both ecdysteroid and JH exerted a promoting effect on the synthesis of Vg. In contrast, the Vg uptake was markedly inhibited by JH while stimulating effect of the ecdysteroid could be shown that vitellin (Vt) titer in the ovary was lower after methoprene treatments, but higher after 20 hydroxyecdyson treatments. Meanwhile, effects of these two hormones on Vg synthesis in the fat body were also tested with the incubation in vitro with Grace medium containing 3H leucine and the hormones. The results demonstrated that Vg synthesis was stimulated after treating with methoprene alone or 20 hydroxyecdysone alone and combined treating with these two chemicals, and particularly ecdysteroid had more marked positive effect. To comprehensively concluded our results, it could be regarded that ecdysteroid play the main role in the regulation of vitellogenesis for the Japanese oak silkworm.
文摘Developmental changes in hemolymph ecdysteroid level, ecdysteroid synthesis by prothoracic glands （PGs） in vitro, prothoracicotropic hormone （PTTH） activity in brain extracts, and PTTH activity in the hemolymph were measured during the fifth larval instar of the Eri silkworm, Samia cynthia ricini. The changing patterns of hemolymph ecdysteroid level and ecdysteroid synthesis by laGs in vitro are similar to each other, with maximums on day 9. However, on this day, hemolymph ecdysteroid level was substantially higher than ecdysteroid synthesis by PGs in vitro suggesting a high PTTH activity in the hemolymph on day 9. Moreover, the changing pattern of PTTH activity in brain extracts is also similar to that of PTTH activity in the hemolymph, both peaking on day 9. However, on this day, activity in brain extracts was much smaller than PTTH activity in the hemolymph implying that most PTTH synthesized by the brain is secreted to the hemolymph and the brain stores a very little amount of PTTH. This study provides unique insights onto the hormonal regulation of ecdysteroid synthesis in the Eri silkworm and is useful for our future studies on signal transduction of insect neurolaelatides.
基金This project was supported by the Special Research Fund of Ghent University(BOF)the Research Foundati on Flanders(FWO-Vlaanderen)to GS.
文摘Insect neuropeptides regulate various physiological processes,such as reproduction,feeding,growth and development,and have been considered as viable targets in the development of alternative strategies for pest control.Amongst these neuropeptides is myosuppressin(MS),a very conserved neuropeptide that has been reported to regulate cardiac and skeletal muscle contractility,feeding and pupal diapause in insects.In this study,we investigated the involvement of MS in fecundity in a notorious defoliator of potato and other solanaceous plants,the Colorado potato beetle(CPB),Leptinotarsa decemlineata.We identified an MS-precursor-encoding transcript in the L.decemlineata transcriptomic database and then evaluated its transcript levels in various CPB tissues.MS transcript levels were found to be highest in the central nervous system,gut and muscle of CPB males and females.To investigate the role of MS in fecundity,MS was silenced in adult CPBs through RNA interference(RNAi).This resulted in a significant reduction in oviposition(over 80%)and oocyte size(69%)in the treated beetles compared to the controls.Also,the reduction in oviposition in treated females was confirmed to be dependent on MS knockdown and independent of male fertilization.Furthermore,MS-knockdown in females resulted in decreased levels of ecdysteroid hormone titers and the transcript levels of its receptor.Interestingly,the injection of 20-hydroxyecdysone into females following MS knockdown could rescue ovary development.Altogether,this study highlights the important role played by MS in regulating fecundity in CPB.
