Germ Cells

Publication Title: 
PLoS genetics

In Caenorhabditis elegans (C. elegans), the promotion of longevity by the transcription factor DAF-16 requires reduced insulin/IGF receptor (IIR) signaling or the ablation of the germline, although the reason for the negative impact of germ cells is unknown. FOXO/DAF-16 activity inhibits germline proliferation in both daf-2 mutants and gld-1 tumors. In contrast to its function as a germline tumor suppressor, we now provide evidence that somatic DAF-16 in the presence of IIR signaling can also result in tumorigenic activity, which counteracts robust lifespan extension.

Author(s): 
Qi, Wenjing
Huang, Xu
Neumann-Haefelin, Elke
Schulze, Ekkehard
Baumeister, Ralf
Publication Title: 
Aging

The C. elegans germline and somatic gonad are actively developing until the animal reaches adulthood, and then continue to undergo striking changes as the animal ages. Reported changes include a depletion of available sperm, a decrease in oocyte quality up till mid-life, a reduction in germline nuclei, a decrease in fertility, and an accumulation of DNA in the midbody of aging C. elegans. Here, we have focused on the aging gonad in old animals, and show in detail that the aging gonad undergoes a massive uterine growth composed of endoreduplicating oocytes, yolk, and expanses of chromatin.

Author(s): 
McGee, Mathew D.
Day, Nicholas
Graham, Jill
Melov, Simon
Publication Title: 
PLoS genetics

In Caenorhabditis elegans (C. elegans), the promotion of longevity by the transcription factor DAF-16 requires reduced insulin/IGF receptor (IIR) signaling or the ablation of the germline, although the reason for the negative impact of germ cells is unknown. FOXO/DAF-16 activity inhibits germline proliferation in both daf-2 mutants and gld-1 tumors. In contrast to its function as a germline tumor suppressor, we now provide evidence that somatic DAF-16 in the presence of IIR signaling can also result in tumorigenic activity, which counteracts robust lifespan extension.

Author(s): 
Qi, Wenjing
Huang, Xu
Neumann-Haefelin, Elke
Schulze, Ekkehard
Baumeister, Ralf
Publication Title: 
Science China. Life Sciences

Aging is a developmental process occurring in all living organisms after reaching a critical developmental stage, characterized by progressive loss of functions until death. Different cells/tissues age differently depending on epigenetics and cell-cell interactions. While males maintain fertility for the most part of their life females only maintain reproductive ability for a short time compared with their lifespan. The interesting question is why and how the females lose fertility so quickly.

Author(s): 
Deng, ManQi
Publication Title: 
Genesis (New York, N.Y.: 2000)

Aging and reproduction are two defining features of our life. Historically, research has focused on the well-documented decline in reproductive capacity that accompanies old age, especially with increasing maternal age in humans. However, recent experiments in model organisms such as worms, flies, and mice have shown that a dialogue in the opposite direction may be widely prevalent, and that signals from reproductive tissues have a significant effect on the rate of aging of organisms. This pathway has been described in considerable detail in the nematode Caenorhabditis elegans.

Author(s): 
Ghazi, Arjumand
Publication Title: 
BioEssays: News and Reviews in Molecular, Cellular and Developmental Biology
Author(s): 
Extavour, Cassandra G.
Publication Title: 
Genetics

It is widely appreciated that larvae of the nematode Caenorhabditis elegans arrest development by forming dauer larvae in response to multiple unfavorable environmental conditions. C. elegans larvae can also reversibly arrest development earlier, during the first larval stage (L1), in response to starvation. "L1 arrest" (also known as "L1 diapause") occurs without morphological modification but is accompanied by increased stress resistance.

Author(s): 
Baugh, L. Ryan
Publication Title: 
Scientific American
Author(s): 
Kirkwood, Thomas
Publication Title: 
Genes & Development

During development of the somatic macronucleus of Tetrahymena thermophila, the rDNA is excised from its germ-line chromosome, rearranged into a palindrome, and amplified to 10(4) copies. We have identified a cis-acting germ-line mutation, rmm11/6, that prevents amplification of the rDNA in all but approximately 1 in 10(5) cells when it is the only rDNA allele in the developing macronucleus. The rmm11/6 mutation resides in a conserved element required for excision, the chromosome breakage sequence (Cbs) flanking the 3' end of the rDNA.

Author(s): 
Kapler, G. M.
Blackburn, E. H.
Publication Title: 
The International Journal of Eating Disorders

OBJECTIVE: To depict the processes through which animals and human beings engage their environment in continuously evolving states of conflict and cooperation. METHOD: Descriptive literature review. RESULTS: Life history outcomes are more relative than they are absolute. Genetic variations play a crucial role, but heavily influencing behavioral outcomes, psychopathology included, are external cues that epigenetically remodel DNA along experience-dependent signaling pathways. The result is phenotypes that either optimize adjustment, or constrain it.

Author(s): 
Strober, Michael
Peris, Tara
Steiger, Howard

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