Juvenile Hormone Induction of the Insect Yolk Protein Precursor

In Leucophaea maderae the female specific protein, or vitellogenin,is being synthesized and secreted exclusively by the adult femalefat bodies. This specific protein, which is induced by thejuvenilehormones makes up approximately 90% of the total yolk proteins.It is a lipophosphoprotein of low phosphorus (0.14) content.The female specific protein is synthesized on polysomes boundto membranes of the ergastoplasmic reticulum (ER). Microsomevesicles obtained from active tissues are heavily studded withribosomes and are considerably more dense than those from "inactive"tissues. The nascent polypeptide chains of the vitellogeninare secreted into the cisternae of the ER and can be releasedby Na deoxycholate digestion of the membranes. Similarly, thenon-specific serum proteins are also secreted into the cisternaeof the ER. All evidence points to the fact that microsomes maycarry mixed populations of polysomes, those associated withspecific and those associated with non-sex-specific proteinsynthesis. The significance of the polysomal association withmembranes for the synthesis of exportable sex-specific proteinis discussed.     

Synthesis of the Thiirane Analogs of Juvenile Hormone III and Other Juvenile Hormone Mimics

Methyl (2E,6E)-10,11-epithio-3,7,11-trimethyl-2,6-dodecadienoate (the thiirane analog of JH III), 6,7-epithiogeranyl 4-methylphenyl ether and 6,7-epithiogeranyl 3,4-methylenedioxyphenyl ether were synthesized. An infrared absorption band at ~1090 cm^?1 was attributable to the thiirane group. The biological activity of these three sulfur-containing JH mimics was tested on Culex pipiens, Aedes aegypti and Spodoptera litura to reveal weak or no JH-like activity.     

Synthesis of Compounds with Juvenile Hormone Activity

A total synthesis of the title compound, a sesquiterpene ester with high juvenile hormone activity, is described.     

Synthesis of Compounds with Juvenile Hormone Activity

A new and convenient non-stereoselective synthetic route to the C₁₈-Cecropia juvenile hormone (as a stereoisomeric mixture) was developed. Employing this method, several juvenile hormone analogues with various alkyl groups at the terminal position were synthesized as stereoisomeric mixtures. Two analogues with two ethyl groups or n-propyl and methyl groups at the terminal position were more active than the C₁₈-Cecropia juvenile hormone on Tenebrio molitor and Tribolium castaneum.     

Synthesis of Compounds with Juvenile Hormone Activity

Two juvabione analogues (III and IV) were synthesized and one (IV) of them was shown to possess the juvenile hormone activity.     

New Insect Juvenile Hormone Mimics: Thiolcarbamates

A prodecure for the quantitative determination of lysinoalanine (LAL) by gas chro-matography-selected ion monitoring was developed. α,ε-Diaminopimelic acid was chosen as the internal standard, and the content of LAL in commercial foods was analyzed. Of the samples analyzed, the content was highest in pidan. Wheat flour-based products (Chinese noodles, pretzels and crackers) and milk products (condensed milk and lactic acid beverages) also contained a significant amount of LAL. Ordinary milk, soybean (soy milk and soy protein isolate) and meat products (ham and Hamburg steak) contained a low amount of LAL. It was confirmed that the possibility of low-level LAL formation existed in foods cooked at home without any alkaline treatment.     

Some 4-Oxa-farnesane Insect Juvenile Hormone Mimics

Synthesis of twentyone 4-oxa-farnesane derivatives with a variety of substitueras at C₁ and C₁₁ is described. Some of these compounds are more active than farnesyl methyl ether against Dysdercus koenigii nymphs.     

Developmental Role of Juvenile Hormone Metabolism in Lepidoptera

SYNOPSIS. Lepidopteran juvenile hormone (JH) esterase appearsto have a functional role in the regulation of embryogenesis,larval growth and development, and adult reproduction. In preovipositionaland newly laid eggs of the tobacco hornworm, Manduca sexta,JH esterase activity was elevated presumably to metabolize maternalJHs, and then declined after blastoderm formation. Also, a singlepeak in hemolymph JH esterase activity was found prior to ecdysisin the second through the fourth instar of M. sexta, the functionof which is unclear. However, in the last instar, elevated hemolymphJH esterase activity was noted prior to wandering and againprior to ecdysis to scavenge the last traces of JH necessaryfor normal development. The hemolymph JH esterase is likelyof multiple tissue origin for the prewandering peak with thefat body excluded as a source for the prepupal peak; an inhibitoryfactor from the brain and JH regulate JH esterase biosynthesis.In adult cabbage loopers, Trichoplusia ni, elevated hemolymphJH esterase activity appeared to be important in reducing theJH titer and preventing egg maturation. Structure/activity datawith trifluoromethylketones were incorporated into the designof a novel, JH esterase inhibitor, the sulfone and hydrate ofoctylthio-1,1,1- trifluoropropan-2-one, with selective and persistent,in vivo inhibitory activity. The topical application of thiscompound to last instar larvae and virgin adults of T. ni producedjuvenizing effects (delayed pupation and induced egg maturation/oviposition,respectively) providing direct evidence of a functional rolefor JH esterase in lepidopteran development.     

Selective Yolk Deposition and Mannose Phosphorylation of Lysosomal Glycosidases in Zebrafish

The regulation and function of lysosomal hydrolases during yolk consumption and embryogenesis in zebrafish are poorly understood. In an effort to better define the lysosomal biochemistry of this organism, we analyzed the developmental expression, biochemical properties, and function of several glycosidases in zebrafish eggs, embryos, and adult tissues. Our results demonstrated that the specific activity of most enzymes increases during embryogenesis, likely reflecting a greater need for turnover within the embryo as yolk-derived nutrients are depleted. Analysis of glycosidase activity in zebrafish and medaka eggs revealed selective deposition of enzymes required for the degradation of N-linked glycans, including an abundance of acidic mannosidases. Treatment of zebrafish embryos with the α-mannosidase inhibitor swainsonine resulted in the accumulation of glycosylated vitellogenin fragments and demonstrated a function for maternally deposited acid α-mannosidase in yolk consumption. Surprisingly, we also found that, unlike mammals, acid α-glucosidase from zebrafish and medaka does not appear to be modified with mannose 6-phosphate residues. We further showed these residues were not acquired on human acid α-glucosidase when expressed in zebrafish embryos, suggesting unique differences in the ability of the human and zebrafish N-acetylglucosamine-1-phosphotransferase to recognize and modify certain lysosomal glycosidases. Together, these results provide novel insight into the role of acidic glycosidases during yolk utilization and the evolution of the mannose 6-phosphate targeting system in vertebrates.     

A Synthesis of dl-C17-Cecropia Juvenile Hormone

A novel synthesis of dl-C₁₇-Cecropia juvenile hormone (I) was accomplished.     

Sexual Dimorphism in Juvenile Hormone Synthesis by Corpora Allata and in Juvenile Hormone Acid Methyltransferase Activity in Corpora Allata and Accessory Sex Glands of Some Lepidoptera

Summary

The kinetic profiles of vitellin accumulation in the oyster ovary during oocyte growth and the effects in vivo and in vitro of estradiol-17β (E₂) on vitellin formation were examined in this study. The relative vitellin content measured by an enzyme-linked immunosorbent assay (ELISA) shows an apparent increase as the oocyte develops. Immunoblotting of the vitellin using anti-vitellin indicated that two main bands (179 and 110 kD), which begin to accumulate at an early stage of maturation, become pronounced during oocyte growth. Meanwhile, the major peak of the intact form of vitellin (530 kD) in gel filtration also enlarges with oocyte growth, supporting the results of immunoblot analysis and vitellin determination. E₂ treatment in vivo causes significant increases in oocyte diameter and vitellin content in the female oyster. A similar trend was observed in ovarian tissues cultured in the presence of E₂. It is concluded that E₂ is one of the major factors which control the vitellogenesis in the oyster and that the ovary is undoubtedly the site of synthesis of vitellin.     

Synthesis of Pyridyl Terpenoid Ether Analogs of Juvenile Hormone

Some pyridyl terpenoid ether analogs of juvenile hormone were synthesized and tested for activity against stored-product insects. Compounds with a longer alkyl side chain were more active.     

A Stereoselective Synthesis of dl-C17-Cecropia Juvenile Hormone

The effects of supplementation with creatine (Cr) and its analog, β-guanidinopropionic acid (β-GPA), on the differentiation of myoblasts and the numbers of nucleoli were studied in C2C12 cells. The cells were cultured in differentiation medium for 4 d. Then Cr (1 mM) or β-GPA (1 mM) was added to the cells, and the mixture was cultured for an additional 2 d. Although the number of myotubes was not different among the groups, myotube diameters and nuclear numbers in myotubes were increased by Cr and β-GPA treatment respectively. The expression of differentiation marker proteins, myogenin, and the myosine heavy chain, was increased in the β-GPA group. Supplementation with β-GPA also increased the percentage of p21 (inhibitor for cell cycle progression)-positive myoblasts. Supplementation with Cr inhibited the decrease in nucleoli numbers, whereas β-GPA increased nucleolar sizes in the myotubes. These results suggest that β-GPA supplementation stimulated the differentiation of myoblasts into multi-nucleated myotubes through induction of p21 expression.     

Juvenile Hormone and host-plant colonization by the black bean aphid, Aphis fabae

Abstract Host-plant colonization by winged, summer forms of Aphis fabae Scop, involves the resumption of embryogenesis and larviposition, leading eventually to flight muscle degeneration. Topical application of Juvenile Hormone I to young adults which (a) had access to the host plant, (b) were starved, (c) were starved and treated with precocene III, or (d) were decapitated shortly after the final ecdysis suggests that embryogenesis and flight muscle histolysis may be stimulated by an increase in Juvenile Hormone titres after settling. The duration of the pre-reproductive period and the initial reproductive rate were not significantly affected, possibly because other neuroendocrine factors are involved in parturition.     

Synthesis and Juvenile Hormone Activity of Some Terpenoid Phenyl Ethers

Thirty eight new compounds with juvenile hormone (JH) activity were synthesized and evaluated biologically on Bombyx mori L. Among them, the activities of 7,8-epoxy-4,8-dimethyl-1 -(p-ethylphenoxy)-3-undecene and 7,8-epoxy-4,8-dimethyl-l-(p-methylphenoxy)-3-undencene were proved to be more than two thousand times as high as that of the C₁₈-Cecropia JH (mixed isomers). Structure-activity relationship of these compounds was discussed.     

Regulation of Juvenile Hormone synthesis in the blowfly Lucilla cuprina

Abstract. Juvenile Hormone III bisepoxide synthesis by ring gland complexes from third-instar larvae of the blowfly Lucilia cuprina Weidemann (Diptera, Calliphoridae) was measured using a radiochemical assay in vitro. Hormone synthesis is regulated by three distinct mechanisms during development of the final larval instar up to the time of pupariation. The first type of regulation is detected as a rapid decline in hormone release coinciding with the final phase of commitment to pupariation. The second is a neurally mediated inhibition by the brain that acts at all stages of development in third-instar larvae. A protease-sensitive factor from brains of third-instar larvae causes dose-dependent reversible inhibition of Juvenile Hormone III bisepoxide synthesis. The third regulatory signal is a neural inhibition, observed in brain-ring gland complexes of prepupal stages. The first two levels of regulation appear to act early in the synthetic pathway for Juvenile Hormone (JH), whereas the third acts on the final steps of bisepoxide synthesis.     

Dewetting Controls Plant Hormone Perception and Initiation of Drought Resistance Signaling

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