3.9 – Hormonal Control of Reproductive Processes
01 Jan 2005-Vol. 3, pp 433-491
TL;DR: In this paper, the authors proposed a 3.9.3.3-approximation algorithm for each node. And they evaluated it on 3.5.3 nodes.
Abstract: 3.9.
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TL;DR: The recently acquired knowledge on the capacity of Met to bind JH, which has been mapped to a particular ligand-binding domain, is summarized, thus establishing this bHLH-PAS protein as a novel type of an intracellular hormone receptor.
Abstract: The molecular action of juvenile hormone (JH), a regulator of vital importance to insects, was until recently regarded as a mystery. The past few years have seen an explosion of studies of JH signaling, sparked by a finding that a JH-resistance gene, Methoprene-tolerant (Met), plays a critical role in insect metamorphosis. Here, we summarize the recently acquired knowledge on the capacity of Met to bind JH, which has been mapped to a particular ligand-binding domain, thus establishing this bHLH-PAS protein as a novel type of an intracellular hormone receptor. Next, we consider the significance of JH-dependent interactions of Met with other transcription factors and signaling pathways. We examine the regulation and biological roles of genes acting downstream of JH and Met in insect metamorphosis. Finally, we discuss the current gaps in our understanding of JH action and outline directions for future research.
627 citations
TL;DR: This chapter updates former reviews on locust polyphenism and also discusses recent findings and refers to the older literature when background information is necessary for complementary and better treatment, or because of historical importance.
Abstract: Publisher Summary This chapter updates former reviews on locust polyphenism and also discusses recent findings. Over 200 articles were published in scientific journals on various aspects of locust phase polyphenism, markedly advancing the knowledge of the subject. However, the chapter refers to the older literature when background information is necessary for complementary and better treatment, or because of historical importance. Some of the recent publications report contradictory findings, and such contradictions have been emphasized in the chapter. Substantial progress has been made in the study of locust phase polyphenism over the past several years. The topic has well and truly emerged from the realms of applied entomology to assume a prominent position in the modern study of phenotypic plasticity, whereby adaptive phenotypes arise during development as a result of plastic interactions between genes and the environment. The study of behavioral gregarization has seen some of the most far-reaching progress. The involvement of locust-emitted volatiles in aspects of phase biology has generated substantial research and its fair share of productive controversy. It has been especially heartening to see that some of the major areas of controversy, such as the role of phenylacetonitrile, appear to have been at least partially resolved during the past year. New genetic resources also offer a solution to a more prosaic problem in locust research. There has been a growing realization that some of the differences reported between laboratories in aspects of phase polyphenism most likely reflect effects of rearing locusts in long-term culture in the laboratory.
402 citations
TL;DR: Phylogenetic analysis using 31 Vg sequences from 25 insect species reflects, in general, the current phylogenies of insects, suggesting that Vgs are still phylogenetically bound, although a divergence exists among them.
375 citations
Cites background or methods from "3.9 – Hormonal Control of Reproduct..."
...…of Vg/ VgR complexes, followed by recycling of receptor back to the oocyte surface and delivery of Vg to mature yolk bodies, where it is processed and stored as Vn for future use (for detail see reviews Raikhel and Dhadialla, 1992; Sappington and Raikhel, 1998; Snigirevskaya and Raikhel, 2005)....
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...The uptake of Vg is achieved by membranebound receptors (VgRs) through receptor-mediated endocytosis (see reviews Raikhel and Dhadialla, 1992; Sappington and Raikhel, 1998; Snigirevskaya and Raikhel, 2005)....
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...…(Vg) is synthesized extra-ovarially by the fat body in tissue-, sex-, and stage-specific manners, secreted into the hemolymph and then sequestered by competent oocytes via receptor-mediated endocytosis (Raikhel and Dhadialla, 1992; Sappington and Raikhel, 1998; Snigirevskaya and Raikhel, 2005)....
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TL;DR: It is shown here that silencing of vitellogenin expression causes a significant increase in JH titer and its putative receptor, which corresponds to a dynamic dose–response.
295 citations
TL;DR: This lecture focuses on the current understanding of JH action at the molecular level in both of these processes based primarily on studies in the tobacco hornworm Manduca sexta, the flour beetle Tribolium castaneum, the mosquito Aedes aegypti, and the fruit fly Drosophila melanogaster.
277 citations
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TL;DR: The role of Ligand in RECEPTOR TRANSFORMATION and ACTIVATION is studied, as well as the role of serotonin, which plays a role in both transformation and inhibition.
Abstract: INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 451 STEROID RECEPTOR SUPERFAMILY . . . . . . . . . . . . . . ... . . ... . . . . . 453 PROTEIN-DNA INTERACTIONS . . . . . . . . . . . . . . . . .. . . .. . . . . . . . . . 455 ROLE OF RECEPTOR IN GENE ACTIVATION AND SILENCING ......... 459 Gene Activation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 459 Gene Silencing . . .. . . .. . ... . . . . . . . . . . . . .... . . . . . ...... . . 462 SYNERGISM BETWEEN DIFFERENT CIS-ACTING ELEMENTS 465 ROLE OF LIGAND IN RECEPTOR TRANSFORMATION AND ACTIVATION . 466 Role of Ligand .... . ... . .. . .... . ..... . . ... . .. . . ........ . 466 Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 471 FACTORS INFLUENCING RECEPTOR ACTIVITY . . . . . . . . . . . . . . . . . . . . 473 Phosphorylation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 473 Ligand-Independent Activation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 475 Nuclear Transcription Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 476 CHROMATIN STRUCTURE AND RECEPTOR ACTION . . . . . . . . . . . . . . . . 479 SUMMARY AND PERSPECTIVES 480
2,960 citations
12 Nov 1998
TL;DR: The aim of this monograph is to clarify the role of pheromones and chemicals in the lives of Insects and to propose a strategy to address their role in the food web.
Abstract: The Insects has been the standard textbook in the field since the first edition published over forty years ago. Building on the strengths of Chapman's original text, this long-awaited 5th edition has been revised and expanded by a team of eminent insect physiologists, bringing it fully up-to-date for the molecular era. The chapters retain the successful structure of the earlier editions, focusing on particular functional systems rather than taxonomic groups and making it easy for students to delve into topics without extensive knowledge of taxonomy. The focus is on form and function, bringing together basic anatomy and physiology and examining how these relate to behaviour. This, combined with nearly 600 clear illustrations, provides a comprehensive understanding of how insects work. Now also featuring a richly illustrated prologue by George McGavin, this is an essential text for students, researchers and applied entomologists alike.
2,922 citations
"3.9 – Hormonal Control of Reproduct..." refers background in this paper
...The insect female reproductive system consists of the ovaries, which contain ovarioles, oviducts, spermatheca, accessory glands, vagina, and ovipositor (Davey, 1985; Chapman, 1998)....
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TL;DR: It is concluded that juvenile hormone deficiency, which results from InR signal pathway mutation, is sufficient to extend life-span, and that in flies, insulin-like ligands nonautonomously mediate aging through retardation of growth or activation of specific endocrine tissue.
Abstract: The Drosophila melanogaster gene insulin-like receptor (InR) is homologous to mammalian insulin receptors as well as to Caenorhabditis elegans daf-2, a signal transducer regulating worm dauer formation and adult longevity. We describe a heteroallelic, hypomorphic genotype of mutant InR, which yields dwarf females with up to an 85% extension of adult longevity and dwarf males with reduced late age-specific mortality. Treatment of the long-lived InR dwarfs with a juvenile hormone analog restores life expectancy toward that of wild-type controls. We conclude that juvenile hormone deficiency, which results from InR signal pathway mutation, is sufficient to extend life-span, and that in flies, insulin-like ligands nonautonomously mediate aging through retardation of growth or activation of specific endocrine tissue.
1,552 citations
"3.9 – Hormonal Control of Reproduct..." refers background in this paper
...Females with an IR mutation are longer lived but deficient in JH synthesis by the CA and ovarian ecdysteroid production (Tatar et al., 2001; Tu et al., 2002)....
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TL;DR: Despite the similarities among mammals and invertebrates in insulin-like peptides and their signal cascade, more research is needed to determine whether these signals control aging in the same way in all the species by the same mechanism.
Abstract: Reduced signaling of insulin-like peptides increases the life-span of nematodes, flies, and rodents. In the nematode and the fly, secondary hormones downstream of insulin-like signaling appear to regulate aging. In mammals, the order in which the hormones act is unresolved because insulin, insulin-like growth factor-1, growth hormone, and thyroid hormones are interdependent. In all species examined to date, endocrine manipulations can slow aging without concurrent costs in reproduction, but with inevitable increases in stress resistance. Despite the similarities among mammals and invertebrates in insulin-like peptides and their signal cascade, more research is needed to determine whether these signals control aging in the same way in all the species by the same mechanism.
1,241 citations