Demography of genotypes: failure of the limited life-span paradigm in Drosophila melanogaster

1993 ◽  
Vol 9 (1) ◽  
pp. 6
Science ◽  
1992 ◽  
Vol 258 (5081) ◽  
pp. 461-463 ◽  
Author(s):  
J. Curtsinger ◽  
H. Fukui ◽  
D. Townsend ◽  
J. Vaupel

1999 ◽  
Vol 19 (6) ◽  
pp. 4093-4100 ◽  
Author(s):  
Odile Begel ◽  
Jocelyne Boulay ◽  
Beatrice Albert ◽  
Eric Dufour ◽  
Annie Sainsard-Chanet

ABSTRACT Podospora anserina is a filamentous fungus with a limited life span. It expresses a degenerative syndrome called senescence, which is always associated with the accumulation of circular molecules (senDNAs) containing specific regions of the mitochondrial chromosome. A mobile group II intron (α) has been thought to play a prominent role in this syndrome. Intron α is the first intron of the cytochrome c oxidase subunit I gene (COX1). Mitochondrial mutants that escape the senescence process are missing this intron, as well as the first exon of theCOX1 gene. We describe here the first mutant of P. anserina that has the α sequence precisely deleted and whose cytochrome c oxidase activity is identical to that of wild-type cells. The integration site of the intron is slightly modified, and this change prevents efficient homing of intron α. We show here that this mutant displays a senescence syndrome similar to that of the wild type and that its life span is increased about twofold. The introduction of a related group II intron into the mitochondrial genome of the mutant does not restore the wild-type life span. These data clearly demonstrate that intron α is not the specific senescence factor but rather an accelerator or amplifier of the senescence process. They emphasize the role that intron α plays in the instability of the mitochondrial chromosome and the link between this instability and longevity. Our results strongly support the idea that in Podospora, “immortality” can be acquired not by the absence of intron α but rather by the lack of active cytochromec oxidase.


Psychiatry ◽  
1961 ◽  
Vol 24 (4) ◽  
pp. 318-323 ◽  
Author(s):  
Lawrence LeShan ◽  
Eda LeShan
Keyword(s):  

Author(s):  
Anthony Parton

An abstract and non-objective style of painting, Rayism ("Luchizm") was pioneered by the Russian artist Mikhail Larionov in early 1912. The style represented the first theoretically coherent and practically consistent response on the part of the Russian avant-garde to the challenges of French Cubism and Italian Futurism. In divorcing art from figuration and in its emphasis on the purely formal qualities of painting, Rayism prepared the way for the development of both Suprematism and Constructivism. Larionov’s innovative style was practiced chiefly by those artists in his immediate orbit: painters such as Natalia Goncharova, Alexander Shevchenko, and Mikhail Le-Dantiyu, who belonged to the Donkey’s Tail and Target group. While Rayism had a limited life-span in Russia, being overtaken by Suprematism in 1915, Larionov and Goncharova continued to practice the style throughout their careers, executing Rayist paintings right up to the 1950s. In its earliest phase, known as "Realistic Rayism" ("Realistichesky luchizm"), the style proceeded from Larionov’s interest in optics and Impressionist color theory and specifically from the idea that the color, contour, and form of our world is defined by rays of light reflected from all material objects. According to Larionov’s booklet Rayism (Luchizm) of 1912, his initial aim was to explore the nature of visual perception as it exists before the brain converts what we see into a comprehensible form.


2005 ◽  
Vol 15 (22) ◽  
pp. 2063-2068 ◽  
Author(s):  
Johannes H. Bauer ◽  
Peter C. Poon ◽  
Heather Glatt-Deeley ◽  
John M. Abrams ◽  
Stephen L. Helfand

mBio ◽  
2018 ◽  
Vol 9 (4) ◽  
Author(s):  
David Fast ◽  
Aashna Duggal ◽  
Edan Foley

ABSTRACTAdultDrosophila melanogasterraised in the absence of symbiotic bacteria have fewer intestinal stem cell divisions and a longer life span than their conventionally reared counterparts. However, we do not know if increased stem cell divisions are essential for symbiont-dependent regulation of longevity. To determine if individual symbionts cause aging-dependent death inDrosophila, we examined the impacts of common symbionts on host longevity. We found that monoassociation of adultDrosophilawithLactobacillus plantarum, a widely reported fly symbiont and member of the probioticLactobacillusgenus, curtails adult longevity relative to germfree counterparts. The effects ofLactobacillus plantarumon life span were independent of intestinal aging. Instead, we found that association withLactobacillus plantarumcauses an extensive intestinal pathology within the host, characterized by loss of stem cells, impaired epithelial renewal, and a gradual erosion of epithelial ultrastructure. Our study uncovers an unknown aspect ofLactobacillus plantarum-Drosophilainteractions and establishes a simple model to characterize symbiont-dependent disruption of intestinal homeostasis.IMPORTANCEUnder homeostatic conditions, gut bacteria provide molecular signals that support the organization and function of the host intestine. Sudden shifts in the composition or distribution of gut bacterial communities impact host receipt of bacterial cues and disrupt tightly regulated homeostatic networks. We used theDrosophila melanogastermodel to determine the effects of prominent fly symbionts on host longevity and intestinal homeostasis. We found that monoassociation withLactobacillus plantarumleads to a loss of intestinal progenitor cells, impaired epithelial renewal, and disruption of gut architecture as flies age. These observations uncover a novel phenotype caused by monoassociation of a germfree host with a common symbiont and establish a simple model to characterize symbiont-dependent loss of intestinal homeostasis.


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