Effects of Altered Catecholamine Metabolism on Pigmentation and Physical Properties of Sclerotized Regions in the Silkworm Melanism Mutant

Catecholamine metabolism plays an important role in the determination of insect body color and cuticle sclerotization. To date, limited research has focused on these processes in silkworm. In the current study, we analyzed the interactions between catecholamines and melanin genes and their effects on the pigmentation patterns and physical properties of sclerotized regions in silkworm, using the melanic mutant melanism (mln) silkworm strain as a model. Injection of β-alanine into mln mutant silkworm induced a change in catecholamine metabolism and turned its body color yellow. Further investigation of the catecholamine content and expression levels of the corresponding melanin genes from different developmental stages of Dazao-mln (mutant) and Dazao (wild-type) silkworm revealed that at the larval and adult stages, the expression patterns of melanin genes precipitated dopamine accumulation corresponding to functional loss of Bm-iAANAT, a repressive effect of excess NBAD on ebony, and upregulation of tan in the Dazao-mln strain. During the early pupal stage, dopamine did not accumulate in Dazao-mln, since upregulation of ebony and black genes led to conversion of high amounts of dopamine into NBAD, resulting in deep yellow cuticles. Scanning electron microscope analysis of a cross-section of adult dorsal plates from both wild-type and mutant silkworm disclosed the formation of different layers in Dazao-mln owing to lack of NADA, compared to even and dense layers in Dazao. Analysis of the mechanical properties of the anterior wings revealed higher storage modulus and lower loss tangent in Dazao-mln, which was closely associated with the altered catecholamine metabolism in the mutant strain. Based on these findings, we conclude that catecholamine metabolism is crucial for the color pattern and physical properties of cuticles in silkworm. Our results should provide a significant contribution to Lepidoptera cuticle tanning research.

[1]  C. Jiggins,et al.  Convergent, modular expression of ebony and tan in the mimetic wing patterns of Heliconius butterflies , 2011, Development Genes and Evolution.

[2]  Camilo Salazar,et al.  Chromosomal rearrangements maintain a polymorphic supergene controlling butterfly mimicry , 2011, Nature.

[3]  M. Dalíková,et al.  Industrial Melanism in British Peppered Moths Has a Singular and Recent Mutational Origin , 2011, Science.

[4]  T. Fukatsu,et al.  Laccase2 is required for cuticular pigmentation in stinkbugs. , 2011, Insect biochemistry and molecular biology.

[5]  Wei Guo,et al.  Modulation of behavioral phase changes of the migratory locust by the catecholamine metabolic pathway , 2011, Proceedings of the National Academy of Sciences.

[6]  R. Beeman,et al.  Mechanical properties of the beetle elytron, a biological composite material. , 2011, Biomacromolecules.

[7]  R. Beeman,et al.  Mechanical properties of elytra from Tribolium castaneum wild-type and body color mutant strains. , 2010, Journal of insect physiology.

[8]  Muwang Li,et al.  Disruption of an N-acetyltransferase gene in the silkworm reveals a novel role in pigmentation , 2010, Development.

[9]  A. Bear,et al.  The Genetic, Morphological, and Physiological Characterization of a Dark Larval Cuticle Mutation in the Butterfly, Bicyclus anynana , 2010, PloS one.

[10]  Q. Xia,et al.  Repression of tyrosine hydroxylase is responsible for the sex-linked chocolate mutation of the silkworm, Bombyx mori , 2010, Proceedings of the National Academy of Sciences.

[11]  R. Futahashi,et al.  Species‐specific coordinated gene expression and trans‐regulation of larval color pattern in three swallowtail butterflies , 2010, Evolution & development.

[12]  B. Moussian,et al.  Recent advances in understanding mechanisms of insect cuticle differentiation. , 2010, Insect biochemistry and molecular biology.

[13]  F. Dai,et al.  Mutations of an Arylalkylamine-N-acetyltransferase, Bm-iAANAT, Are Responsible for Silkworm Melanism Mutant* , 2010, The Journal of Biological Chemistry.

[14]  S. O. Andersen.  Insect cuticular sclerotization: a review. , 2010, Insect biochemistry and molecular biology.

[15]  Y. Arakane,et al.  Tyrosine hydroxylase is required for cuticle sclerotization and pigmentation in Tribolium castaneum. , 2010, Insect biochemistry and molecular biology.

[16]  R. Futahashi,et al.  Caterpillar color patterns are determined by a two‐phase melanin gene prepatterning process: new evidence from tan and laccase2 , 2010, Evolution & development.

[17]  T. Shimada,et al.  Yellow-e Determines the Color Pattern of Larval Head and Tail Spots of the Silkworm Bombyx mori* , 2009, The Journal of Biological Chemistry.

[18]  P. Wittkopp,et al.  Intraspecific Polymorphism to Interspecific Divergence: Genetics of Pigmentation in Drosophila , 2009, Science.

[19]  N. Dittmer,et al.  Characterization of endogenous and recombinant forms of laccase-2, a multicopper oxidase from the tobacco hornworm, Manduca sexta. , 2009, Insect biochemistry and molecular biology.

[20]  E. Hassan,et al.  Phenol–formaldehyde‐type resins made from phenol‐liquefied wood for the bonding of particleboard , 2009 .

[21]  R. Beeman,et al.  Molecular and Functional Analyses of Amino Acid Decarboxylases Involved in Cuticle Tanning in Tribolium castaneum* , 2009, The Journal of Biological Chemistry.

[22]  Jinjun Wang,et al.  Scanning electron microscopy studies of antennal sensilla of bruchid beetles, Callosobruchus chinensis (L.) and Callosobruchus maculatus (F.) (Coleoptera: Bruchidae). , 2009, Micron.

[23]  L. Riddiford,et al.  The molecular mechanisms of cuticular melanization: the ecdysone cascade leading to dopa decarboxylase expression in Manduca sexta. , 2009, Insect biochemistry and molecular biology.

[24]  A. Guo,et al.  Reduction of Dopamine Level Enhances the Attractiveness of Male Drosophila to Other Males , 2009, PloS one.

[25]  P. Wittkopp,et al.  Development and evolution of insect pigmentation: genetic mechanisms and the potential consequences of pleiotropy. , 2009, Seminars in cell & developmental biology.

[26]  T. Shimada,et al.  yellow and ebony Are the Responsible Genes for the Larval Color Mutants of the Silkworm Bombyx mori , 2008, Genetics.

[27]  B. Lemaître,et al.  Drosophila Serpin-28D regulates hemolymph phenoloxidase activity and adult pigmentation. , 2008, Developmental biology.

[28]  C. Wicker-Thomas,et al.  Interaction of dopamine, female pheromones, locomotion and sex behavior in Drosophila melanogaster. , 2008, Journal of insect physiology.

[29]  A. Guo,et al.  Behavioral / Systems / Cognitive Increased Dopamine Level Enhances Male – Male Courtship in Drosophila , 2008 .

[30]  S. O. Andersen.  Involvement of tyrosine residues, N-terminal amino acids, and beta-alanine in insect cuticular sclerotization. , 2007, Insect biochemistry and molecular biology.

[31]  S. O. Andersen,et al.  Aspects of cuticular sclerotization in the locust, Scistocerca gregaria, and the beetle, Tenebrio molitor. , 2007, Insect biochemistry and molecular biology.

[32]  R. Futahashi,et al.  Melanin-synthesis enzymes coregulate stage-specific larval cuticular markings in the swallowtail butterfly, Papilio xuthus , 2005, Development Genes and Evolution.

[33]  R. Beeman,et al.  Laccase 2 is the phenoloxidase gene required for beetle cuticle tanning. , 2005, Proceedings of the National Academy of Sciences of the United States of America.

[34]  R. Pendleton,et al.  A developmental role for catecholamines in Drosophila behavior , 2005, Pharmacology Biochemistry and Behavior.

[35]  D. Grimaldi,et al.  New light shed on the oldest insect , 2004, Nature.

[36]  J. True.  Insect melanism: the molecules matter , 2003 .

[37]  Artyom Kopp,et al.  Evolution in black and white: genetic control of pigment patterns in Drosophila. , 2003, Trends in genetics : TIG.

[38]  P. Koch,et al.  Insect pigmentation: activities of beta-alanyldopamine synthase in wing color patterns of wild-type and melanic mutant swallowtail butterfly Papilio glaucus. , 2000, Pigment cell research.

[39]  K. Menard.  Dynamic Mechanical Analysis: A Practical Introduction , 1997 .

[40]  K. Kramer,et al.  N-β-Alanyldopamine metabolism for puparial tanning in wild-type and mutant niger strains of the mediterranean fruit fly, Ceratitis capitata , 1996 .

[41]  K. Kramer,et al.  Role of catecholamines and β-alanine in puparial color of wild-type and melanic mutants of the mediterranean fruit fly (Ceratitis capitata) , 1996 .

[42]  S. O. Andersen,et al.  Cuticular sclerotization in insects , 1996 .

[43]  K. Kramer,et al.  White pupa: a Ceratitis capitata mutant lacking catecholamines for tanning the puparium , 1995 .

[44]  W. L. Harries,et al.  Dynamic mechanical analysis of polymeric materials , 1990 .

[45]  K. Kramer,et al.  Catecholamines and related o-diphenols in cockroach hemolymph and cuticle during sclerotization and melanization: comparative studies on the order Dictyoptera , 2004, Journal of Comparative Physiology B.

[46]  M. Sugumaran.  Unified Mechanism for Sclerotization of Insect Cuticle , 1998 .

[47]  H. Biessmann,et al.  Catecholamine metabolism and in vitro induction of premature cuticle melanization in wild type and pigmentation mutants of Drosophila melanogaster. , 1996, Archives of insect biochemistry and physiology.

[48]  K. Kramer,et al.  Cuticular strength and pigmentation of five strains of adult Blattella germanica (L.) during sclerotization: Correlations with catecholamines, β-alanine and food deprivation , 1990 .

[49]  K. Kramer,et al.  Catecholamines in the cuticles of four strains of the german cockroach Blattella germanica (L.) during sclerotization and melanization , 1989 .

[50]  K. Tomer,et al.  N-β-alanylnorepinephrine: Biosynthesis in insect cuticle and possible role in sclerotization , 1987 .

[51]  K. Kramer,et al.  Cuticular strength and pigmentation of rust-red and black strains of Tribolium castaneum: Correlation with catecholamine and β-alanine content , 1987 .

[52]  K. Kramer,et al.  Catecholamines in haemolymph and cuticle during larval, pupal and adult development of Manduca sexta (L.) , 1984 .

[53]  R. Beeman,et al.  Catecholamines and β-alanine in the red flour beetle, Tribolium castaneum: Roles in cuticle sclerotization and melanization☆ , 1984 .

[54]  E. Turi,et al.  Thermal characterization of polymeric materials , 1981 .

[55]  T. Murayama,et al.  Dynamic mechanical analysis of polymeric material , 1978 .