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https://www.readbyqxmd.com/read/28934747/untangling-longevity-dauer-and-healthspan-in-caenorhabditis-elegans-insulin-igf-1-signalling
#1
Collin Yvès Ewald, Jorge Iván Castillo-Quan, T Keith Blackwell
The groundbreaking discovery that lower levels of insulin/IGF-1 signaling (IIS) can induce lifespan extension was reported 24 years ago in the nematode Caenorhabditis elegans. In this organism, mutations in the insulin/IGF-1 receptor gene daf-2 or other genes in this pathway can double lifespan. Subsequent work has revealed that reduced IIS (rIIS) extends lifespan across diverse species, possibly including humans. In C. elegans, IIS also regulates development into the diapause state known as dauer, a quiescent larval form that enables C...
September 22, 2017: Gerontology
https://www.readbyqxmd.com/read/28928280/the-enigma-of-embryonic-diapause
#2
REVIEW
Marilyn B Renfree, Jane C Fenelon
Embryonic diapause - a period of embryonic suspension at the blastocyst stage - is a fascinating phenomenon that occurs in over 130 species of mammals, ranging from bears and badgers to mice and marsupials. It might even occur in humans. During diapause, there is minimal cell division and greatly reduced metabolism, and development is put on hold. Yet there are no ill effects for the pregnancy when it eventually continues. Multiple factors can induce diapause, including seasonal supplies of food, temperature, photoperiod and lactation...
September 15, 2017: Development
https://www.readbyqxmd.com/read/28925346/the-effect-of-winter-length-on-duration-of-dormancy-and-survival-of-specialized-herbivorous-rhagoletis-fruit-flies-from-high-elevation-environments-with-acyclic-climatic-variability
#3
J Rull, E Tadeo, R Lasa, M Aluja
Dormancy can be defined as a state of suppressed development allowing insects to cope with adverse conditions and plant phenology. Among specialized herbivorous insects exploiting seasonal resources, diapause frequently evolves as a strategy to adjust to predictable plant seasonal cycles. To cope with acyclic and unpredictable climatic events, it has been found for some insects that a proportion of the population undergoes prolonged dormancy. We compared the response of three species in the Rhagoletis cingulata species group exploiting plants differing in fruiting phenology from environments varying in frequency and timing of acyclic climatic catastrophic events (frost during flowering and fruit set) and varying also in the time of the onset of the rainy season...
September 19, 2017: Bulletin of Entomological Research
https://www.readbyqxmd.com/read/28919018/de-novo-transcriptome-assembly-of-the-calanoid-copepod-neocalanus-flemingeri-a-new-resource-for-emergence-from-diapause
#4
Vittoria Roncalli, Matthew C Cieslak, Stephanie A Sommer, Russell R Hopcroft, Petra H Lenz
Copepods, small planktonic crustaceans, are key links between primary producers and upper trophic levels, including many economically important fishes. In the subarctic North Pacific, the life cycle of copepods like Neocalanus flemingeri includes an ontogenetic migration to depth followed by a period of diapause (a type of dormancy) characterized by arrested development and low metabolic activity. The end of diapause is marked by the production of the first brood of eggs. Recent temperature anomalies in the North Pacific have raised concerns about potential negative effects on N...
September 14, 2017: Marine Genomics
https://www.readbyqxmd.com/read/28904750/phenology-of-brown-marmorated-stink-bug-described-using-female-reproductive-development
#5
Anne L Nielsen, Shelby Fleischer, George C Hamilton, Tori Hancock, Gregorz Krawczyk, Jana C Lee, Emily Ogburn, John M Pote, Amy Raudenbush, Ann Rucker, Michael Saunders, Victoria P Skillman, Jeanne Sullivan, Jody Timer, James Walgenbach, Nik G Wiman, Tracy C Leskey
Temperature-based degree-day models describe insect seasonality and to predict key phenological events. We expand on the use of a temperature-based process defining timing of reproduction through the incorporation of female reproductive physiology for the invasive pentatomid species Halyomorpha halys, the brown marmorated stink bug. A five-stage ranking system based on ovary development was able to distinguish between the reproductive statuses of field-collected females. Application of this ranking method described aspects of H...
September 2017: Ecology and Evolution
https://www.readbyqxmd.com/read/28901587/serum-estradiol-and-progesterone-profiles-during-estrus-pseudopregnancy-and-active-gestation-in-steller-sea-lions
#6
Renae Sattler, Lori Polasek
While the proximate driver behind the decline of the Western stock of Steller sea lions (Eumetopias jubatus, >80% since 1970s) is likely multifactorial, the population reduction may have been powered by a decrease in fecundity. A harvest of Steller sea lions in the 1970s and 80s revealed a 30% reduction in the proportion of pregnant females from early (October-November) to late gestation (April-May). Identification and quantification of these reproductive failures are difficult when we lack species-specific data on endocrinology associated with discrete stages of the reproductive cycle (i...
September 13, 2017: Zoo Biology
https://www.readbyqxmd.com/read/28893508/regulation-of-protein-phosphatase-2a-during-embryonic-diapause-process-in-the-silkworm-bombyx-mori
#7
Shi-Hong Gu, Hsiao-Yen Hsieh, Pei-Ling Lin
Regulation of protein phosphorylation requires coordinated interactions between protein kinases and protein phosphatases. In the present study, we investigated regulation of protein phosphatase 2A (PP2A) during the embryonic diapause process of B. mori. An immunobloting analysis showed that Bombyx eggs contained a catalytic C subunit, a major 55-kDa regulatory B subunit (B55/PR55 subunit), and a structural A subunit, with the A and B subunits undergoing differential changes between diapause and non-diapause eggs during embryonic process...
September 8, 2017: Journal of Insect Physiology
https://www.readbyqxmd.com/read/28893327/new-activity-of-yamamarin-an-insect-pentapeptide-on-immune-system-of-mealworm-tenebrio-molitor
#8
K Walkowiak-Nowicka, G Nowicki, M Kuczer, G Rosiński
In insects, two types of the immune responses, cellular and humoral, constitute a defensive barrier against various parasites and pathogens. In response to pathogens, insects produce a wide range of immune agents that act on pathogens directly, such as cecropins or lysozyme, or indirectly by the stimulation of hemocyte migration or by increasing phenoloxidase (PO) activity. Recently, many new immunologically active substances from insects, such as peptides and polypeptides, have been identified. Nevertheless, in the most cases, their physiological functions are not fully known...
September 12, 2017: Bulletin of Entomological Research
https://www.readbyqxmd.com/read/28869698/biogeographic-responses-of-the-copepod-calanus-glacialis-to-a-changing-arctic-marine-environment
#9
Zhixuan Feng, Rubao Ji, Carin Ashjian, Robert Campbell, Jinlun Zhang
Dramatic changes have occurred in the Arctic Ocean over the past few decades, especially in terms of sea ice loss and ocean warming. Those environmental changes may modify the planktonic ecosystem with changes from lower to upper trophic levels. This study aimed to understand how the biogeographic distribution of a crucial endemic copepod species, Calanus glacialis, may respond to both abiotic (ocean temperature) and biotic (phytoplankton prey) drivers. A copepod individual-based model coupled to an ice-ocean-biogeochemical model was utilized to simulate temperature- and food-dependent life cycle development of C...
September 4, 2017: Global Change Biology
https://www.readbyqxmd.com/read/28854112/characterization-of-tolypocladium-cylindrosporum-hypocreales-ophiocordycipitaceae-and-its-impact-against-aedes-aegypti-and-aedes-albopictus-eggs-at-low-temperature
#10
Lina B Flor-Weiler, Alejandro P Rooney, Robert W Behle, Ephantus J Muturi
We examined the growth characteristics of Tolypocladium cylindrosporum IBT 41712 and its potential to infect eggs of Aedes aegypti and Ae. albopictus at a low temperature (15°C). When grown on Sabouraud dextrose agar supplemented with yeast extract, the IBT 41712 formed white colonies turning to a slightly darker, off-white color when mature. The mycelia bore swollen conidiophores producing smooth-walled, oblong to cylindrical conidia with varying sizes, ranging from 1.5 to 3.5 μm long. To determine the optimum temperature for the fungus, we cultured the fungus at eight temperatures (4°C, 12°C, 15°C, 21°C, 28°C, 33°C, 37°C, and 40°C) and measured the diametric growth...
September 2017: Journal of the American Mosquito Control Association
https://www.readbyqxmd.com/read/28830356/pheromone-modulates-two-phenotypically-plastic-traits-adult-reproduction-and-larval-diapause-in-the-nematode-caenorhabditis-elegans
#11
Barney Wharam, Laura Weldon, Mark Viney
BACKGROUND: Animals use information from their environment to make decisions, ultimately to maximize their fitness. The nematode C. elegans has a pheromone signalling system, which hitherto has principally been thought to be used by worms in deciding whether or not to arrest their development as larvae. Recent studies have suggested that this pheromone can have other roles in the C. elegans life cycle. RESULTS: Here we demonstrate a new role for the C. elegans pheromone, showing that it accelerates hermaphrodites' reproductive rate, a phenomenon which we call pheromone-dependent reproductive plasticity (PDRP)...
August 22, 2017: BMC Evolutionary Biology
https://www.readbyqxmd.com/read/28805640/nutritional-endocrine-and-social-influences-on-reproductive-physiology-at-the-origins-of-social-behavior
#12
REVIEW
Karen M Kapheim
Understanding the evolutionary origins of social behavior in insects requires understanding the physiological basis for reproductive plasticity. Solitary bees and wasps or those living in small, flexible societies will be key to understanding how conserved pathways have evolved to give rise to reproductive castes. Nutrient-sensing and endocrine pathways are decoupled from reproduction in some life stages of social insects. Heterochrony, particularly as it is related to diapause physiology, may be an important mechanism by which this decoupling occurs...
August 2017: Current Opinion in Insect Science
https://www.readbyqxmd.com/read/28791459/three-year-lifecycle-large-body-and-very-high-threshold-temperature-in-the-cricket-gryllus-argenteus-for-special-adaptation-to-desiccation-cycle-in-malawi
#13
Takuya Kosumi, Makio Takeda
In temperate climates, the initiation and termination of diapause synchronize the stress-tolerant stage with the stressful season and reproduction with the non-stressful season in many insects. Synchronization is often regulated by photoperiodism.Voltinism and the ultimate size of adults are also important determinants for their lifecycle, and different diapause stages and voltinism patterns are known in crickets.Here, we investigated the life history of the African cricket Gryllus argenteus from Malawi, which is a typical arid tropical highland...
August 8, 2017: Die Naturwissenschaften
https://www.readbyqxmd.com/read/28776797/micrornas-are-differentially-abundant-during-aedes-albopictus-diapause-maintenance-but-not-diapause-induction
#14
Z A Batz, A C Goff, P A Armbruster
Diapause is a programmed dormancy that allows organisms to tolerate predictable periods of unfavourable conditions by temporarily halting development and reducing metabolism. Diapause is widespread amongst insects and is crucial for allowing organisms to coordinate their growth and reproduction with favourable environmental conditions. Although the adaptive significance of diapause is well understood, the molecular mechanisms underpinning diapause remain unresolved. We performed high-throughput sequencing to investigate the role of microRNAs (miRNAs) in the diapause of the Asian tiger mosquito, Aedes albopictus...
August 4, 2017: Insect Molecular Biology
https://www.readbyqxmd.com/read/28751650/rhoa-phosphorylation-mediated-by-rho-rhoa-associated-kinase-pathway-improves-the-anti-freezing-potentiality-of-murine-hatched-and-diapaused-blastocysts
#15
Meichao Gu, Hemin Ni, Xihui Sheng, Alfredo Pauciullo, Yunhai Liu, Yong Guo
Embryonic cryopreservation has a relatively low survival rate because of cytoskeletal damage. However, molecular anti-freezing mechanisms have been largely unexplored. This study investigated the significance of RhoA, involved in embryonic development, and the Rho/RhoA-associated kinase (ROCK) signalling pathway in cryopreservation. The anti-freezing mechanism in murine dormant embryos, compared with normal blastocysts, was assessed by combining molecular, physiological and pharmacological approaches. Real-time PCR and western blotting experiments showed high RhoA expression in cryo-dormant and dormant embryos...
July 27, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28750999/pigmentary-analysis-of-eggs-of-the-silkworm-bombyx-mori
#16
Haiyan Zhang, Ying Lin, Guanwang Shen, Xue Tan, Chao Lei, Wei Long, Hongling Liu, Yandi Zhang, Yinying Xu, Jinxin Wu, Jianjian Gu, Qingyou Xia, Ping Zhao
Ommochromes are major pigments involved in coloration of eggs, eyes, wings, and epidermis of insects. Bombyx mori (silkworm) eggs contain a mixture of ommochrome pigments and their precursors. Here, we analyzed the pigment composition of every egg color strain using egg color mutants (w-2, pe, and re) and wild-type strains (dazao and C108) by using full wavelength scanning and high-performance liquid chromatography. We identified ommochrome pigments and their precursors in pigment extracts from non-diapause eggs and diapause eggs, and found that the quantities of ommochrome precursor 3-hydroxy-kynurenine were much higher in the diapause eggs...
August 2017: Journal of Insect Physiology
https://www.readbyqxmd.com/read/28747475/daphniid-zooplankton-assemblage-shifts-in-response-to-eutrophication-and-metal-contamination-during-the-anthropocene
#17
Mary Alta Rogalski, Peter R Leavitt, David K Skelly
Human activities during the Anthropocene result in habitat degradation that has been associated with biodiversity loss and taxonomic homogenization of ecological communities. Here we estimated effects of eutrophication and heavy metal contamination, separately and in combination, in explaining zooplankton species composition during the past 125-145 years using analysis of daphniid diapausing egg banks from four lakes in the northeastern USA. We then examined how these community shifts influenced patterns of diversity and homogenization...
July 26, 2017: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/28735962/enhancement-of-antiviral-capacity-of-transgenic-silkworms-against-cytoplasmic-polyhedrosis-virus-via-knockdown-of-multiple-viral-genes
#18
Liang Jiang, Zhengwen Peng, Huizhen Guo, Jingchen Sun, Qiang Sun, Fei Xia, Chunlin Huang, Guowen Xu, Qingyou Xia
Bombyx mori cytoplasmic polyhedrosis virus (BmCPV), a major pathogen of silkworms, causes serious economic losses in sericulture. The BmCPV genome contains 10 discrete dsRNA segments; among these, S1, S2, S3, S4, S6, and S7 encode virus structural proteins, whereas S5, S8, S9, and S10 encode nonstructural proteins. In an attempt to create an anti-BmCPV silkworm strain, we constructed transgenic RNAi vector pb-CNS for knockdown of S5, S8, S9, and S10, and pb-SNS targeting S1, S2, S4, S5, and S8. Transgenic silkworm line CNS and SNS were generated via microinjection of the practical diapause silkworm strain Furong...
July 20, 2017: Developmental and Comparative Immunology
https://www.readbyqxmd.com/read/28726267/day-length-constrains-the-time-budget-of-aphid-predators
#19
Jens Joschinski, Tim Kiess, Jochen Krauss
Phenology shifts and range expansions cause organisms to experience novel day length - temperature correlations. Depending on the temporal niche, organisms may benefit or suffer from changes in day length, thus potentially affecting phenological adaptation. We assessed the impact of day length changes on larvae of Chrysoperla carnea (Stephens) and Episyrphus balteatus (De Geer), both of which prey on aphids. Larvae of E. balteatus are night-active, whereas those of C. carnea appear to be crepuscular. We subjected both species in climate chambers to day lengths of 16 : 8 LD and, to circumvent diapause responses, 20 : 4 LD...
July 20, 2017: Insect Science
https://www.readbyqxmd.com/read/28724647/physiological-responses-to-fluctuating-temperatures-are-characterized-by-distinct-transcriptional-profiles-in-a-solitary-bee
#20
Alex S Torson, George D Yocum, Joseph P Rinehart, Sean A Nash, Kally M Kvidera, Julia H Bowsher
Exposure to stressful low temperatures during development can result in the accumulation of deleterious physiological effects called chill injury. Metabolic imbalances, disruptions in ion homeostasis, and oxidative stress contribute to the increased mortality of chill-injured insects. Interestingly, survival can be significantly increased when chill susceptible insects are exposed to a daily warm-temperature pulse during chilling. We hypothesize that warm pulses allow for the repair of damage associated with chill-injury...
July 19, 2017: Journal of Experimental Biology
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