In insects,melanism,a fundamental pigmentation process,is of significant importance in evolutionary biology due to its complex genetic foundation.We investigated the role of the RNA-binding gene Musashi(msi)in melanis...In insects,melanism,a fundamental pigmentation process,is of significant importance in evolutionary biology due to its complex genetic foundation.We investigated the role of the RNA-binding gene Musashi(msi)in melanism in Laodelphax striatellus,a Hemiptera species.We identified a single L.striatellus msi homolog,Lsmsi,encoding a 357 amino acid protein with 2 RNA recognition motifs.RNA interference-mediated knockdown of LsMsi resulted in complete body melanism and increased cuticular permeability.Additionally,we found the involvement of G protein-coupled receptor A42 and tyrosine hydroxylase(Th)in L.striatellus melanism.Knockdown of LsTh lightened the epidermis,showing dehydration signs,while LsA42 knockdown enhanced LsTh expression,leading to melanism.Surprisingly,Lsmsi knockdown decreased both LsA42 and LsTh expression,which was expected to cause whitening but resulted in melanism.Further,we found that Lsmsi influenced downstream genes like phenoloxidase homolog LsPo and dopa decarboxylase(Ddc)homolog LsDdc in the tyrosine-mediated melanism pathway.Extending to Nilaparvata lugens and Sogatella furcifera,we demonstrated the conserved role of msi in melanism among Delphacidae.Given MSI proteins’roles in cancer and tumors in vertebrates,our study is the first to link msi in insects to Delphacidae body color melanization via the tyrosine-mediated pathway,offering fresh perspectives on the genetic basis of insect melanism and msi functions.展开更多
Polymorphisms for melanic form of insects may provide various selective advantages.However,melanic alleles may have significant/subtle pleiotrophic“costs.”Several potential pleiotrophic effects of the W(=Y)‐linked ...Polymorphisms for melanic form of insects may provide various selective advantages.However,melanic alleles may have significant/subtle pleiotrophic“costs.”Several potential pleiotrophic effects of the W(=Y)‐linked melanism gene in Papilio glaucus L.(Lepidoptera)showed no costs for melanic versus yellow in adult size,oviposition preferences,fecundity,egg viability,larval survival/growth rates,cold stress tolerance,or postdiapause emergence times.Sexual selection(males choosing yellow rather than mimetic dark females)had been suggested to provide a balanced polymorphism in P.glaucus,but spermatophore counts in wild females and direct field tethering studies of size‐matched pairs of virgin females(dark and yellow),show that male preferences are random or frequency‐dependent from Florida to Michigan,providing no yellow counter‐advantages.Recent frequency declines of dark(melanic/mimetic)females in P.glaucus populations are shown in several major populations from Florida(27.3°N latitude)to Ohio(38.5°N).Summer temperatures have increased significantly at all these locations during this time(1999–2018),but whether dark morphs may be more vulnerable(in any stage)to such climate warming remains to be determined.Additional potential reasons for the frequency declines in mimetic females are discussed:(i)genetic introgression of Z‐linked melanism suppressor genes from P.canadensis(R&J)and the hybrid species,P.appalachiensis(Pavulaan&Wright),(ii)differential developmental incompatibilities,or Haldane effects,known to occur in hybrids,(iii)selection against intermediately melanic(“dusty”)females(with the W‐linked melanic gene,b+)which higher temperatures can cause.展开更多
Non-signaling functions of coloration include thermoregulation(thermal melanism hypothesis),protection against ultraviolet radiation(photoprotection hypothesis),and concealment from predators(crypsis hypothesis).We in...Non-signaling functions of coloration include thermoregulation(thermal melanism hypothesis),protection against ultraviolet radiation(photoprotection hypothesis),and concealment from predators(crypsis hypothesis).We investigated whether dorsal coloration in 19 populations of spiny-footed lizards,Acanthodactylus erythrurus,across the Iberian Peninsula varies according to these functions.We captured adult males and females in each population and calculated standardized dorsum brightness estimates from photographs.We also calculated standardized ground luminosity estimates and gathered information on latitude,altitude,mean annual temperature,and mean annual solar radiation for each location.Males showed a higher percentage of black coloration and a more contrasted dorsum than females,suggesting different selection pressures on dorsal coloration in both sexes.Furthermore,males showed a darker dorsum and a higher percentage of black coloration at higher altitudes and when the ground was darker.In contrast,females exhibited a darker dorsum only when the ground was darker and a higher percentage of black coloration only at higher altitudes.We also observed that the variation of dorsum luminosity within males and the variation of dorsum luminosity among females within populations were both positively related to the variation of ground luminosity among different points within locations.Latitude,temperature,and solar radiation were not signifcantly related to dorsal coloration in either sex.Our results support the photoprotection and crypsis hypotheses in males and,to some extent,in females,whereas the thermal melanism hypothesis is weakly supported in both sexes.These fndings suggest that there is local adaptation in the dorsal coloration of the spiny-footed lizard.展开更多
In polymorphic mammalian species that display multiple color forms, those with dark, or melanic pelage would be prone to overheating, especially if they live in warm climates, because their fur absorbs solar energy at...In polymorphic mammalian species that display multiple color forms, those with dark, or melanic pelage would be prone to overheating, especially if they live in warm climates, because their fur absorbs solar energy at a higher rate. However, experimental studies indicate that certain physical properties of fur of dark individuals appear to prevent, or minimize heat stress, although it is not clear what properties do so. Here, we tested the possibility that black-furred individuals simply have shorter or thinner hair fibers, which would create a lighter （in terms of weight） coat or one that allows greater air flow for evaporative coo- ling. We examined museum specimens of eastern fox squirrels Sciurus niger, a species native to the United States and one that displays brown, grey or all-black pelage color, and used image analysis procedures to quantify hairs from the dorsal surface and tail. From examination of 43 specimens （19 brown, 9 black and 15 grey）, and 1,720 hairs, we found no significant difference in hair lengths across color morphs, but significant differences in hair fiber widths. Black squirrels had thinner body hairs than other forms （7% thinner）, but thicker tail hairs （9% thicker） than the others. Given that the dorsal surface would be directly exposed to solar radiation, we interpret this to be an adaptation to prevent heat stress during the day. The thicker tail hairs may be an adapta- tion for nighttime thermoregulation, since squirrels sleep with their tails wrapped around their bodies. These results add to a growing literature body of the functional significance of mammalian pelage [Current Zoology 57 （6）： 731-736, 2011].展开更多
A new analytical solution for ground surface settlement induced by deep excavation is proposed based on the elastic half space Melan’s solution,and the analytical model is related to the physical and mechanical prope...A new analytical solution for ground surface settlement induced by deep excavation is proposed based on the elastic half space Melan’s solution,and the analytical model is related to the physical and mechanical properties of soil with the loading and unloading action during excavation process.The change law of earth pressure of the normal consolidation soil after the foundation pit excavation was analyzed,and elastic displacement calculation methods of analytic solution were further established given the influence of excavation and unloading.According to the change of stress state in the excavation process of foundation pit,the planar mechanical analysis model of the foundation excavation problem was established.By combining this model with the physical equations and geometric equations of plane strain problem with consideration of the loading and unloading modulus of soil,constitutive equation of the plane strain problem was also established.The loading and unloading modulus formula was obtained by using the parameter calculation method in Duncan-Chang curve model.The constitutive equation obtained from the model was used to calculate the soil stress state of each point to determine its loading and unloading modulus.Finally,the foundation pit displacement change after excavation was calculated,and thus the soil pressure distribution after retaining structure deformation.The theoretical results calculated by making corresponding programs were applied to engineering practice.By comparing the conventional calculation results with monitoring results,the practicability and feasibility of the calculation model were verified,which should provide a theoretical basis for similar projects.展开更多
AIM： To use the tyrosinase minigene as a visual marker to perform microinjection training and improve the techniques related with transgene to greatly elevate the effidency of gene transfer. METHODS： A mouse tyrosin...AIM： To use the tyrosinase minigene as a visual marker to perform microinjection training and improve the techniques related with transgene to greatly elevate the effidency of gene transfer. METHODS： A mouse tyrosinase minigene, i.e., TyBS, in which the 2.25-kb authentic genomic 5＇ non-coding flanking sequence of mouse tyrosinase was fused to a mouse tyrosinase cDNA, was introduced into the fertilized eggs of outbred Kunming albino mice. RESULTS： Of the 11 animals that developed from the injected eggs, two mice （P1 and #8） exhibited pigmented hair （P1） and eyes （P1 and #8）, as confirmed by PCR analysis for the tyrosinase minigene integrated into the genome. When founder P1 was bred to Kunming male mouse, six progeny out of 11 offspring inherited the transgene and the pigmented-eye phenotype. CONCLUSION： Taken together, these results suggest that this minigene encodes the active tyrosinase protein and that its 5＇ flanking region contains the sequences regulating the expression of mouse tyrosinase gene as expected. We have rescued the albino phenotype by introduction and expression of a functional tyrosinase minigene in the Kunming albino mouse and the transgene can be passed to subsequent generation. These findings also indicate that TyBS can be a useful visual marker gene in the co-transgenic experiments.展开更多
Laccase（EC 1.10.3.2）is known to oxidize various aromatic and nonaromatic compounds via a radical-catalyzed reaction,which generally includes two types of laccase,Lac1 and Lac2.Lac1 oxidizes toxic compounds in the di...Laccase（EC 1.10.3.2）is known to oxidize various aromatic and nonaromatic compounds via a radical-catalyzed reaction,which generally includes two types of laccase,Lac1 and Lac2.Lac1 oxidizes toxic compounds in the diet,and Lac2 is known to play an important role in melanizing the insect exoskeleton.In this study,we cloned and sequenced the cDNA of the diamondback moth,Plutella xylostella Lac2（PxLac2）,from the third instar larvae using polymerase chain reaction（PCR）and rapid amplification of cDNA ends techniques.The results showed that the full-length PxLac2 cDNA was 1 944 bp long and had an open reading frame of 1 794 bp.PxLac2 encoded a protein with 597 amino acids and had a molecular weight of 66.09 kDa.Moreover,we determined the expression levels of PxLac2 in different stages by quantitative PCR（qPCR）.The results indicated that PxLac2 was expressed differently in different stages.We observed the highest expression level in pupae and the lowest expression level in fourth instar larvae.We also investigated the enzymatic properties of laccase,which had optimal activity at pH 3.0 and at 35°C.Under these optimal conditions,laccase had a Michaelis constant（Km）of 0.97 mmol L-1,maximal reaction speed（Vm）of 56.82 U mL-1,and activation energy（Ea）of 17.36 kJ mol-1 to oxidize2,2＇-azino-bis（3-ethylbenzothiazoline-6-sulfonic acid ammonium salt）.Type II copper enhanced laccase activity below 0.8mmol L-1 and reduced enzyme activity above 0.8 mmol L-1 with an IC50 concentration of 1.26 mmol L-1.This study provides insights into the biological function of laccase.展开更多
Melanization/pigmentation is an important physiological phenomenon in insects,which is involved incuticular tanning,parasite encapsulation,and egg shell hardening.During the past few years,we have beenusing mosquito e...Melanization/pigmentation is an important physiological phenomenon in insects,which is involved incuticular tanning,parasite encapsulation,and egg shell hardening.During the past few years,we have beenusing mosquito eggs as a model to study the detailed biochemistry of melanization reactions in mosquitoes.Chorion of newly oviposited eggs is white and soft,but the chorion becomes black and hard within 3～4 hfollowing oviposition. Once the chorion turns black,the eggs become resistant to desiccation and solubiliza-tion.Floodwater mosquitoes,such as Aedes aegypti,oviposit on substrates at the edge of water and theeggs hatch only after being flooded with water following adequate rainfall.Consequently,the ability towithstand the desiccation and other environmental adversities is critical for egg survival.Our research deal-ing with chorion melanization in mosquitoes is aimed at understanding the biochemical processes and mech-展开更多
基金Welfare Research Program of Zhejiang Province(LQ21C140006)National Natural Science Foundation of China(32372516 and 32230086)Key Projects of Ningbo Natural Science Foundation(2023j015)for the support.
文摘In insects,melanism,a fundamental pigmentation process,is of significant importance in evolutionary biology due to its complex genetic foundation.We investigated the role of the RNA-binding gene Musashi(msi)in melanism in Laodelphax striatellus,a Hemiptera species.We identified a single L.striatellus msi homolog,Lsmsi,encoding a 357 amino acid protein with 2 RNA recognition motifs.RNA interference-mediated knockdown of LsMsi resulted in complete body melanism and increased cuticular permeability.Additionally,we found the involvement of G protein-coupled receptor A42 and tyrosine hydroxylase(Th)in L.striatellus melanism.Knockdown of LsTh lightened the epidermis,showing dehydration signs,while LsA42 knockdown enhanced LsTh expression,leading to melanism.Surprisingly,Lsmsi knockdown decreased both LsA42 and LsTh expression,which was expected to cause whitening but resulted in melanism.Further,we found that Lsmsi influenced downstream genes like phenoloxidase homolog LsPo and dopa decarboxylase(Ddc)homolog LsDdc in the tyrosine-mediated melanism pathway.Extending to Nilaparvata lugens and Sogatella furcifera,we demonstrated the conserved role of msi in melanism among Delphacidae.Given MSI proteins’roles in cancer and tumors in vertebrates,our study is the first to link msi in insects to Delphacidae body color melanization via the tyrosine-mediated pathway,offering fresh perspectives on the genetic basis of insect melanism and msi functions.
基金This research was supported in part by the College of Natural Science and the Michigan Agricultural Experiment Station(Project#1644)the National Science Foundation(DEB 9201122,DEB 9981608,DEB-0716683,and DEB 0918879)。
文摘Polymorphisms for melanic form of insects may provide various selective advantages.However,melanic alleles may have significant/subtle pleiotrophic“costs.”Several potential pleiotrophic effects of the W(=Y)‐linked melanism gene in Papilio glaucus L.(Lepidoptera)showed no costs for melanic versus yellow in adult size,oviposition preferences,fecundity,egg viability,larval survival/growth rates,cold stress tolerance,or postdiapause emergence times.Sexual selection(males choosing yellow rather than mimetic dark females)had been suggested to provide a balanced polymorphism in P.glaucus,but spermatophore counts in wild females and direct field tethering studies of size‐matched pairs of virgin females(dark and yellow),show that male preferences are random or frequency‐dependent from Florida to Michigan,providing no yellow counter‐advantages.Recent frequency declines of dark(melanic/mimetic)females in P.glaucus populations are shown in several major populations from Florida(27.3°N latitude)to Ohio(38.5°N).Summer temperatures have increased significantly at all these locations during this time(1999–2018),but whether dark morphs may be more vulnerable(in any stage)to such climate warming remains to be determined.Additional potential reasons for the frequency declines in mimetic females are discussed:(i)genetic introgression of Z‐linked melanism suppressor genes from P.canadensis(R&J)and the hybrid species,P.appalachiensis(Pavulaan&Wright),(ii)differential developmental incompatibilities,or Haldane effects,known to occur in hybrids,(iii)selection against intermediately melanic(“dusty”)females(with the W‐linked melanic gene,b+)which higher temperatures can cause.
基金funded by the European Regional Development Fund(ERDF A way of making Europe)and the Spanish Ministry of Education and Science(grant CGL2008-00137/BOS).
文摘Non-signaling functions of coloration include thermoregulation(thermal melanism hypothesis),protection against ultraviolet radiation(photoprotection hypothesis),and concealment from predators(crypsis hypothesis).We investigated whether dorsal coloration in 19 populations of spiny-footed lizards,Acanthodactylus erythrurus,across the Iberian Peninsula varies according to these functions.We captured adult males and females in each population and calculated standardized dorsum brightness estimates from photographs.We also calculated standardized ground luminosity estimates and gathered information on latitude,altitude,mean annual temperature,and mean annual solar radiation for each location.Males showed a higher percentage of black coloration and a more contrasted dorsum than females,suggesting different selection pressures on dorsal coloration in both sexes.Furthermore,males showed a darker dorsum and a higher percentage of black coloration at higher altitudes and when the ground was darker.In contrast,females exhibited a darker dorsum only when the ground was darker and a higher percentage of black coloration only at higher altitudes.We also observed that the variation of dorsum luminosity within males and the variation of dorsum luminosity among females within populations were both positively related to the variation of ground luminosity among different points within locations.Latitude,temperature,and solar radiation were not signifcantly related to dorsal coloration in either sex.Our results support the photoprotection and crypsis hypotheses in males and,to some extent,in females,whereas the thermal melanism hypothesis is weakly supported in both sexes.These fndings suggest that there is local adaptation in the dorsal coloration of the spiny-footed lizard.
文摘In polymorphic mammalian species that display multiple color forms, those with dark, or melanic pelage would be prone to overheating, especially if they live in warm climates, because their fur absorbs solar energy at a higher rate. However, experimental studies indicate that certain physical properties of fur of dark individuals appear to prevent, or minimize heat stress, although it is not clear what properties do so. Here, we tested the possibility that black-furred individuals simply have shorter or thinner hair fibers, which would create a lighter （in terms of weight） coat or one that allows greater air flow for evaporative coo- ling. We examined museum specimens of eastern fox squirrels Sciurus niger, a species native to the United States and one that displays brown, grey or all-black pelage color, and used image analysis procedures to quantify hairs from the dorsal surface and tail. From examination of 43 specimens （19 brown, 9 black and 15 grey）, and 1,720 hairs, we found no significant difference in hair lengths across color morphs, but significant differences in hair fiber widths. Black squirrels had thinner body hairs than other forms （7% thinner）, but thicker tail hairs （9% thicker） than the others. Given that the dorsal surface would be directly exposed to solar radiation, we interpret this to be an adaptation to prevent heat stress during the day. The thicker tail hairs may be an adapta- tion for nighttime thermoregulation, since squirrels sleep with their tails wrapped around their bodies. These results add to a growing literature body of the functional significance of mammalian pelage [Current Zoology 57 （6）： 731-736, 2011].
基金Project(41672290)supported by the National Natural Science Foundation of ChinaProject(2016J01189)supported by the Natural Science foundation of Fujian Province,China
文摘A new analytical solution for ground surface settlement induced by deep excavation is proposed based on the elastic half space Melan’s solution,and the analytical model is related to the physical and mechanical properties of soil with the loading and unloading action during excavation process.The change law of earth pressure of the normal consolidation soil after the foundation pit excavation was analyzed,and elastic displacement calculation methods of analytic solution were further established given the influence of excavation and unloading.According to the change of stress state in the excavation process of foundation pit,the planar mechanical analysis model of the foundation excavation problem was established.By combining this model with the physical equations and geometric equations of plane strain problem with consideration of the loading and unloading modulus of soil,constitutive equation of the plane strain problem was also established.The loading and unloading modulus formula was obtained by using the parameter calculation method in Duncan-Chang curve model.The constitutive equation obtained from the model was used to calculate the soil stress state of each point to determine its loading and unloading modulus.Finally,the foundation pit displacement change after excavation was calculated,and thus the soil pressure distribution after retaining structure deformation.The theoretical results calculated by making corresponding programs were applied to engineering practice.By comparing the conventional calculation results with monitoring results,the practicability and feasibility of the calculation model were verified,which should provide a theoretical basis for similar projects.
基金Supported by the National Natural Science Foundation of China, No. 30271177 and No. 39870676 National 9th Five-year Program, No. 101033+3 种基金 Major Science and Technology Projects of Guangdong Province, No. B602 Natural Science Foundation of Guangdong Province, No. 021903 Postdoctoral Fellowship Foundation of China (Series 29) Special Fund of Scientific Instrument Collaborative Share-net in Guangzhou. No. 2006176
文摘AIM： To use the tyrosinase minigene as a visual marker to perform microinjection training and improve the techniques related with transgene to greatly elevate the effidency of gene transfer. METHODS： A mouse tyrosinase minigene, i.e., TyBS, in which the 2.25-kb authentic genomic 5＇ non-coding flanking sequence of mouse tyrosinase was fused to a mouse tyrosinase cDNA, was introduced into the fertilized eggs of outbred Kunming albino mice. RESULTS： Of the 11 animals that developed from the injected eggs, two mice （P1 and #8） exhibited pigmented hair （P1） and eyes （P1 and #8）, as confirmed by PCR analysis for the tyrosinase minigene integrated into the genome. When founder P1 was bred to Kunming male mouse, six progeny out of 11 offspring inherited the transgene and the pigmented-eye phenotype. CONCLUSION： Taken together, these results suggest that this minigene encodes the active tyrosinase protein and that its 5＇ flanking region contains the sequences regulating the expression of mouse tyrosinase gene as expected. We have rescued the albino phenotype by introduction and expression of a functional tyrosinase minigene in the Kunming albino mouse and the transgene can be passed to subsequent generation. These findings also indicate that TyBS can be a useful visual marker gene in the co-transgenic experiments.
基金supported financially by the National Natural Science Foundation of China (31672046)the National Key Research and Development Program of China (2016YFD0200500)the Funds of Shandong "Double Tops" Program, China (SYL2017YSTD06)
文摘Laccase（EC 1.10.3.2）is known to oxidize various aromatic and nonaromatic compounds via a radical-catalyzed reaction,which generally includes two types of laccase,Lac1 and Lac2.Lac1 oxidizes toxic compounds in the diet,and Lac2 is known to play an important role in melanizing the insect exoskeleton.In this study,we cloned and sequenced the cDNA of the diamondback moth,Plutella xylostella Lac2（PxLac2）,from the third instar larvae using polymerase chain reaction（PCR）and rapid amplification of cDNA ends techniques.The results showed that the full-length PxLac2 cDNA was 1 944 bp long and had an open reading frame of 1 794 bp.PxLac2 encoded a protein with 597 amino acids and had a molecular weight of 66.09 kDa.Moreover,we determined the expression levels of PxLac2 in different stages by quantitative PCR（qPCR）.The results indicated that PxLac2 was expressed differently in different stages.We observed the highest expression level in pupae and the lowest expression level in fourth instar larvae.We also investigated the enzymatic properties of laccase,which had optimal activity at pH 3.0 and at 35°C.Under these optimal conditions,laccase had a Michaelis constant（Km）of 0.97 mmol L-1,maximal reaction speed（Vm）of 56.82 U mL-1,and activation energy（Ea）of 17.36 kJ mol-1 to oxidize2,2＇-azino-bis（3-ethylbenzothiazoline-6-sulfonic acid ammonium salt）.Type II copper enhanced laccase activity below 0.8mmol L-1 and reduced enzyme activity above 0.8 mmol L-1 with an IC50 concentration of 1.26 mmol L-1.This study provides insights into the biological function of laccase.
文摘Melanization/pigmentation is an important physiological phenomenon in insects,which is involved incuticular tanning,parasite encapsulation,and egg shell hardening.During the past few years,we have beenusing mosquito eggs as a model to study the detailed biochemistry of melanization reactions in mosquitoes.Chorion of newly oviposited eggs is white and soft,but the chorion becomes black and hard within 3～4 hfollowing oviposition. Once the chorion turns black,the eggs become resistant to desiccation and solubiliza-tion.Floodwater mosquitoes,such as Aedes aegypti,oviposit on substrates at the edge of water and theeggs hatch only after being flooded with water following adequate rainfall.Consequently,the ability towithstand the desiccation and other environmental adversities is critical for egg survival.Our research deal-ing with chorion melanization in mosquitoes is aimed at understanding the biochemical processes and mech-
