1 Introduction Lady beetle (Coccinella septempunctata) is an important natural enemy of aphids.Our data show that JH produced in the corpora allata (CA) in the adult beetle playsa key role in regulating its reproducti...1 Introduction Lady beetle (Coccinella septempunctata) is an important natural enemy of aphids.Our data show that JH produced in the corpora allata (CA) in the adult beetle playsa key role in regulating its reproduction. Recently, it is demonstrated that CA ininsects are target tissues of allatostatin and allatotropin. Juvenile hormone (JH) issynthesized and released by CA and plays a vital role in insect development, primarilyin the control of metamorphosis, sexual maturation and reproduction. The activity ofCA during reproduction could be modulated by stimulatory factors (Allatotropicfactor, ATF), inhibitory factors (Allatostatic factor AST) or both.展开更多
Juvenile hormone （JH）, a sesquiterpenoid synthetized by the insect corpora allata （CA）, plays critical roles in metamorphosis and reproduction. Penultimate or last step of JH synthesis is catalyzed by juvenile hor...Juvenile hormone （JH）, a sesquiterpenoid synthetized by the insect corpora allata （CA）, plays critical roles in metamorphosis and reproduction. Penultimate or last step of JH synthesis is catalyzed by juvenile hormone acid O-methyltransferase （JHAMT）. Here we report the cloning and expression analysis of the JHAMT orthologue in the cockroach, Blattella germanica （L.） （BgJHAMT）. BgJHAMT is mainly expressed in CA, with only expression traces in ovary. Three different isoforms, differing in the 3＇-UTR sequence, were identified. Isoform A shows between 35 and 65 times higher expression than B and C in CA from penultimate nymphal instar and adult females. RNAi-triggered knock down of BgJHAMT produces a dramatic reduction of JH synthesis, concomitant with a decrease of fat body viteUogenin expression and basal follicle length. BgJHAMT mRNA levels in CA of females along the gonadotrophic cycle parallel, with a slight advancement, JH synthesis profile. BgJHAMT mRNA levels were reduced in starved females and in females in which we reduced nutritional signaling by knocking down insulin receptor and target of rapamycin （TOR）. Results show that conditions that modify JH synthesis in adult B. germanica females show parallel changes of BgJHAMT mRNA levels and that the JH-specifie branch of the JH synthesis pathway is regulated in the same way as the mevalonate branch. Furthermore, we demonstrate that nutrition and its signaling through the insulin receptor and TOR pathways are essential for activating BgJHAMT expression, which suggests that this enzyme can be a checkpoint for the regulation of JH production in relation to nutritional status.展开更多
The juvenile hormones (JH) are critical to the contro1 of insect development andreproduction. The production of JH by the corpora allata (CA) is regulatd in part bypeptides originating from brain. One group of these p...The juvenile hormones (JH) are critical to the contro1 of insect development andreproduction. The production of JH by the corpora allata (CA) is regulatd in part bypeptides originating from brain. One group of these peptides termed allatostatins (AST)reversibly inhibits the biosynthesis of JH invitro. The correlation of these events suggeststhat AST, i.e. their biosynthesis, are important in the regulation of JH biosynthesis.展开更多
基金Project supported by the National Natural Science Foundation of China.
文摘1 Introduction Lady beetle (Coccinella septempunctata) is an important natural enemy of aphids.Our data show that JH produced in the corpora allata (CA) in the adult beetle playsa key role in regulating its reproduction. Recently, it is demonstrated that CA ininsects are target tissues of allatostatin and allatotropin. Juvenile hormone (JH) issynthesized and released by CA and plays a vital role in insect development, primarilyin the control of metamorphosis, sexual maturation and reproduction. The activity ofCA during reproduction could be modulated by stimulatory factors (Allatotropicfactor, ATF), inhibitory factors (Allatostatic factor AST) or both.
文摘Juvenile hormone （JH）, a sesquiterpenoid synthetized by the insect corpora allata （CA）, plays critical roles in metamorphosis and reproduction. Penultimate or last step of JH synthesis is catalyzed by juvenile hormone acid O-methyltransferase （JHAMT）. Here we report the cloning and expression analysis of the JHAMT orthologue in the cockroach, Blattella germanica （L.） （BgJHAMT）. BgJHAMT is mainly expressed in CA, with only expression traces in ovary. Three different isoforms, differing in the 3＇-UTR sequence, were identified. Isoform A shows between 35 and 65 times higher expression than B and C in CA from penultimate nymphal instar and adult females. RNAi-triggered knock down of BgJHAMT produces a dramatic reduction of JH synthesis, concomitant with a decrease of fat body viteUogenin expression and basal follicle length. BgJHAMT mRNA levels in CA of females along the gonadotrophic cycle parallel, with a slight advancement, JH synthesis profile. BgJHAMT mRNA levels were reduced in starved females and in females in which we reduced nutritional signaling by knocking down insulin receptor and target of rapamycin （TOR）. Results show that conditions that modify JH synthesis in adult B. germanica females show parallel changes of BgJHAMT mRNA levels and that the JH-specifie branch of the JH synthesis pathway is regulated in the same way as the mevalonate branch. Furthermore, we demonstrate that nutrition and its signaling through the insulin receptor and TOR pathways are essential for activating BgJHAMT expression, which suggests that this enzyme can be a checkpoint for the regulation of JH production in relation to nutritional status.
文摘The juvenile hormones (JH) are critical to the contro1 of insect development andreproduction. The production of JH by the corpora allata (CA) is regulatd in part bypeptides originating from brain. One group of these peptides termed allatostatins (AST)reversibly inhibits the biosynthesis of JH invitro. The correlation of these events suggeststhat AST, i.e. their biosynthesis, are important in the regulation of JH biosynthesis.
