Diapause in the mosquito Culex pipiens evokes a metabolic switch from blood feeding to sugar gluttony.

A key characteristic of overwintering dormancy (diapause) in the mosquito Culex pipiens is the switch in females from blood feeding to sugar gluttony. We present evidence demonstrating that genes encoding enzymes needed to digest a blood meal (trypsin and a chymotrypsin-like protease) are down-regulated in diapause-destined females, and that concurrently, a gene associated with the accumulation of lipid reserves (fatty acid synthase) is highly up-regulated. As the females then enter diapause, fatty acid synthase is only sporadically expressed, and expression of trypsin and chymotrypsin-like remains undetectable. Late in diapause (2-3 months at 18 degrees C), the genes encoding the digestive enzymes begin to be expressed as the female prepares to take a blood meal upon the termination of diapause. Our results thus underscore a molecular switch that either capacitates the mosquito for blood feeding (nondiapause) or channels the adult mosquito exclusively toward sugar feeding and lipid sequestration (diapause).

[1]  E. Vinogradova.  Culex pipiens pipiens mosquitoes : taxonomy, distribution, ecology, physiology, genetics, applied importance and control , 2000 .

[2]  M. H. Chen,et al.  Juvenile hormone biosynthesis in diapausing and nondiapausing Culex pipiens (Diptera: Culicidae). , 1999, Journal of medical entomology.

[3]  Y. Han,et al.  Cloning and characterization of a serine protease from the human malaria vector, Anopheles gambiae , 1997, Insect molecular biology.

[4]  M. Wells,et al.  cDNA cloning and pattern of expression of an adult, female-specific chymotrypsin from Aedes aegypti midgut. , 1997, Insect biochemistry and molecular biology.

[5]  J. Pennington,et al.  Early trypsin, a female-specific midgut protease in Aedes aegypti: isolation, aminoterminal sequence determination, and cloning and sequencing of the gene. , 1996, Insect biochemistry and molecular biology.

[6]  F. Catteruccia,et al.  Constitutive and blood meal-induced trypsin genes in Anopheles gambiae. , 1995, Experimental parasitology.

[7]  E. Goldsmith,et al.  Converting tissue plasminogen activator to a zymogen: a regulatory triad of Asp-His-Ser. , 1993, Science.

[8]  B. White,et al.  Isolation, sequencing and characterization of two cDNA clones coding for trypsin‐like enzymes from the midgut of Aedes aegypti , 1993, Insect molecular biology.

[9]  M. F. Bowen.  Patterns of sugar feeding in diapausing and nondiapausing Culex pipiens (Diptera: Culicidae) females. , 1992, Journal of medical entomology.

[10]  M. F. Bowen.  Post-diapause sensory responsiveness in Culex pipiens , 1990 .

[11]  C. J. Mitchell,et al.  Fate of the blood meal in force-fed, diapausing Culex pipiens (Diptera: Culicidae). , 1989, Journal of medical entomology.

[12]  C. J. Mitchell,et al.  Inability of diapausing Culex pipiens (Diptera: Culicidae) to use blood for producing lipid reserves for overwinter survival. , 1989, Journal of medical entomology.

[13]  W. Liu,et al.  Molecular cloning and sequencing of chicken liver fatty acid synthase cDNA. , 1989, Proceedings of the National Academy of Sciences of the United States of America.

[14]  A. Warshel,et al.  How do serine proteases really work? , 1989, Biochemistry.

[15]  E. E. Davis,et al.  A behavioural and sensory analysis of host-seeking behaviour in the diapausing mosquito Culex pipiens , 1988 .

[16]  P. Chomczyński,et al.  Single-step method of RNA isolation by acid guanidinium thiocyanate-phenol-chloroform extraction. , 1987, Analytical biochemistry.

[17]  P. Boreham,et al.  Population studies, physiological state and mortality factors of overwintering adult populations of females of Culex pipiens L. (Diptera: Culicidae) , 1987 .

[18]  G. Heijne.  A new method for predicting signal sequence cleavage sites. , 1986 .

[19]  D. McGeoch,et al.  On the predictive recognition of signal peptide sequences. , 1985, Virus research.

[20]  G. A. Kerkut,et al.  Comprehensive insect physiology, biochemistry, and pharmacology , 1985 .

[21]  C. J. Mitchell.  Differentiation of host-seeking behavior from blood-feeding behavior in overwintering Culex pipiens (Diptera: Culicidae) and observations on gonotrophic dissociation. , 1983, Journal of medical entomology.

[22]  C. L. Bailey,et al.  Winter survival of blood-fed and nonblood-fed Culex pipiens L. , 1982, The American journal of tropical medicine and hygiene.

[23]  C. L. Bailey,et al.  Experimental hibernation studies in Culex pipiens (Diptera: Culicidae): reactivation of ovarian development and blood-feeding in prehibernating females. , 1979, Journal of medical entomology.

[24]  R. Washino.  The physiological ecology of gonotrophic dissociation and related phenomena in mosquitoes. , 1977, Journal of medical entomology.

[25]  J. Kraut.  Serine proteases: structure and mechanism of catalysis. , 1977, Annual review of biochemistry.

[26]  A. Spielman.  Effect of synthetic juvenile hormone on ovarian diapause of Culex pipiens mosquitoes. , 1974, Journal of medical entomology.

[27]  A. Spielman,et al.  Environmental Control of Ovarian Diapause in Culex pipiens , 1973 .

[28]  J. R. Larsen,et al.  Effect of photoperiod and temperature on ovarian development in Culex pipiens pipiens. , 1973, Journal of insect physiology.

[29]  J. D. Buffington.  Hibernaculum choice in Culex pipiens. , 1972, Journal of medical entomology.

[30]  P. E. Wilcox.  [5] Chymotrypsinogens—chymotrypsins , 1970 .

[31]  L. Lorand,et al.  Methods in enzymology. Volume XIX. Proteolytic enzymes. Volume XIX. , 1970 .

[32]  B. Eldridge.  Environmental Control of Ovarian Development in Mosquitoes of the Culex pipiens Complex , 1966, Science.