scholarly journals Differential mechanisms of tolerance to extreme environmental conditions in tardigrades

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Dido Carrero ◽  
José G. Pérez-Silva ◽  
Víctor Quesada ◽  
Carlos López-Otín
Keyword(s):  
Dna Repair ◽  
Fresh Water ◽  
Environmental Conditions ◽  
Telomere Maintenance ◽  
Extreme Temperatures ◽  
Surrounding Water ◽  
Genomic Features ◽  
Physical Conditions ◽  
Terrestrial Environments ◽  
Water Bears

Abstract Tardigrades, also known as water bears, are small aquatic animals that inhabit marine, fresh water or limno-terrestrial environments. While all tardigrades require surrounding water to grow and reproduce, species living in limno-terrestrial environments (e.g. Ramazzottius varieornatus) are able to undergo almost complete dehydration by entering an arrested state known as anhydrobiosis, which allows them to tolerate ionic radiation, extreme temperatures and intense pressure. Previous studies based on comparison of the genomes of R. varieornatus and Hypsibius dujardini - a less tolerant tardigrade - have pointed to potential mechanisms that may partially contribute to their remarkable ability to resist extreme physical conditions. In this work, we have further annotated the genomes of both tardigrades using a guided approach in search for novel mechanisms underlying the extremotolerance of R. varieornatus. We have found specific amplifications of several genes, including MRE11 and XPC, and numerous missense variants exclusive of R. varieornatus in CHEK1, POLK, UNG and TERT, all of them involved in important pathways for DNA repair and telomere maintenance. Taken collectively, these results point to genomic features that may contribute to the enhanced ability to resist extreme environmental conditions shown by R. varieornatus.

scholarly journals Deficiency in Poly(ADP-ribose) Polymerase-1 (PARP-1) Accelerates Aging and Spontaneous Carcinogenesis in Mice

2008 ◽  
Vol 2008 ◽  
pp. 1-11 ◽  
Author(s):  
Tatiana S. Piskunova ◽  
Maria N. Yurova ◽  
Anton I. Ovsyannikov ◽  
Anna V. Semenchenko ◽  
Mark A. Zabezhinski ◽  
...  
Keyword(s):  
Dna Repair ◽  
Life Span ◽  
Soft Tissues ◽  
Telomere Maintenance ◽  
Biological Aging ◽  
Spontaneous Tumors ◽  
Uterine Tumors ◽  
Dna Repair Gene ◽  
Spontaneous Carcinogenesis ◽  
Parp 1

Genetic and biochemical studies have shown that PARP-1 and poly(ADP-ribosyl)ation play an important role in DNA repair, genomic stability, cell death, inflammation, telomere maintenance, and suppressing tumorigenesis, suggesting that the homeostasis of poly(ADP-ribosyl)ation and PARP-1 may also play an important role in aging. Here we show that PARP- mice exhibit a reduction of life span and a significant increase of population aging rate. Analysis of noninvasive parameters, including body weight gain, body temperature, estrous function, behavior, and a number of biochemical indices suggests the acceleration of biological aging in PARP- mice. The incidence of spontaneous tumors in both PARP- and PARP- groups is similar; however, malignant tumors including uterine tumors, lung adenocarcinomas and hepatocellular carcinomas, develop at a significantly higher frequency in PARP- mice than PARP- mice (72% and 49%, resp.; .05). In addition, spontaneous tumors appear earlier in PARP- mice compared to the wild type group. Histopathological studies revealed a wide spectrum of tumors in uterus, ovaries, liver, lungs, mammary gland, soft tissues, and lymphoid organs in both groups of the mice. These results demonstrate that inactivation of DNA repair gene PARP-1 in mice leads to acceleration of aging, shortened life span, and increased spontaneous carcinogenesis.

scholarly journals Recent Advances in Understanding Werner Syndrome

F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 1779 ◽  
Author(s):  
Raghavendra A. Shamanna ◽  
Deborah L. Croteau ◽  
Jong-Hyuk Lee ◽  
Vilhelm A. Bohr
Keyword(s):  
Dna Repair ◽  
Stem Cell ◽  
Genome Stability ◽  
Werner Syndrome ◽  
Genetic Disorder ◽  
Accelerated Aging ◽  
Nutrient Sensing ◽  
Telomere Maintenance ◽  
Telomere Attrition ◽  
Recent Advances

Aging, the universal phenomenon, affects human health and is the primary risk factor for major disease pathologies. Progeroid diseases, which mimic aging at an accelerated rate, have provided cues in understanding the hallmarks of aging. Mutations in DNA repair genes as well as in telomerase subunits are known to cause progeroid syndromes. Werner syndrome (WS), which is characterized by accelerated aging, is an autosomal-recessive genetic disorder. Hallmarks that define the aging process include genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, deregulation of nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, and altered intercellular communication. WS recapitulates these hallmarks of aging and shows increased incidence and early onset of specific cancers. Genome integrity and stability ensure the normal functioning of the cell and are mainly guarded by the DNA repair machinery and telomeres. WRN, being a RecQ helicase, protects genome stability by regulating DNA repair pathways and telomeres. Recent advances in WS research have elucidated WRN’s role in DNA repair pathway choice regulation, telomere maintenance, resolution of complex DNA structures, epigenetic regulation, and stem cell maintenance.

scholarly journals Interspecific Variations in Duration of Tail Regression in Two Tropical Anurans

2015 ◽  
Vol 2015 ◽  
pp. 1-8
Author(s):  
Cuckoo Mahapatra ◽  
Pravati Kumari Mahapatra
Keyword(s):  
Environmental Conditions ◽  
Rainy Season ◽  
Larval Period ◽  
Evolutionary Strategies ◽  
Interspecific Difference ◽  
Extreme Temperatures ◽  
Larval Phase ◽  
Morphological Variations ◽  
Interspecific Variations ◽  
Tadpole Tail

Anurans breed in an array of habitats and hence employ a variety of evolutionary strategies to adapt to the variable conditions. Particularly, since they undergo a larval phase they develop mechanisms to overcome unfavourable conditions like desiccation, extreme temperatures, and so forth. The anurans, Polypedates maculatus and Duttaphrynus melanostictus, show noticeable variation in the duration of larval period and tadpole tail regression. D. melanostictus breeds throughout the year and hence is subjected to different environmental conditions as compared to P. maculatus which breeds only during the rainy season. Thus, the tadpoles of D. melanostictus have selected to undergo a shorter larval period and duration of tail regression to suit their breeding habits. The present study correlates the interspecific difference in the duration of tail regression with the morphological variations in the tails of the two species. D. melanostictus shortens the duration of larval tail regression by having comparatively larger and more number of melanocytes and a thinner notochord than P. maculatus.

LOSS OF TLD SIGNAL DUE TO HIGH TEMPERATURE ENVIRONMENTAL CONDITIONS

2019 ◽  
Vol 187 (1) ◽  
pp. 17-20
Author(s):  
Andrew Villanueva ◽  
Braden Goddard
Keyword(s):  
Saudi Arabia ◽  
High Temperature ◽  
Elevated Temperature ◽  
United Arab Emirates ◽  
High Temperatures ◽  
Environmental Conditions ◽  
Statistical Difference ◽  
Light Output ◽  
Nuclear Industry ◽  
Extreme Temperatures

Abstract While it is known that temperatures above 100°C have an effect on the reported dose of a TLD, it is less widely known what the susceptibility is to temperatures below 100°C, temperatures humans could reasonably expect to be exposed to. With the expanding nuclear industry in climates with more extreme temperatures, (e.g. United Arab Emirates and Saudi Arabia) the effect on a TLD if left on a dashboard of a car need to be evaluated. This research experimentally determined the extent of this thermal susceptibility by testing a range of high temperatures, 40°C – 90°C. The experimental results found that there is a statistically significant reduction in TLD-100H (natLiF:Mg,Cu,P) light output for TLDs there were exposed to temperatures as low as 40°C for 8 hour durations and 50°C for 2 hour durations. There is statistical difference in TLD-100H light output for elevated temperature durations of 8 hours compared to 24 hours.

Expression of genes involved in DNA repair and telomere maintenance in the yeast Hansenula polymorpha DL1 under heat stress

2015 ◽  
Vol 462 (1) ◽  
pp. 185-188 ◽  
Author(s):  
A. V. Beletsky ◽  
A. N. Malyavko ◽  
M. V. Sukhanova ◽  
E. S. Mardanova ◽  
M. E. Zvereva ◽  
...  
Keyword(s):  
Dna Repair ◽  
Heat Stress ◽  
Hansenula Polymorpha ◽  
Telomere Maintenance ◽  
Expression Of Genes

scholarly journals The Guardian of the Genome Revisited: p53 Downregulates Genes Required for Telomere Maintenance, DNA Repair, and Centromere Structure

Cancers ◽  
2018 ◽  
Vol 10 (5) ◽  
pp. 135 ◽  
Author(s):  
Eléonore Toufektchan ◽  
Franck Toledo
Keyword(s):  
Dna Repair ◽  
P53 Protein ◽  
Bone Marrow Failure ◽  
Dyskeratosis Congenita ◽  
Telomere Maintenance ◽  
Recent Analysis ◽  
Phenotypic Traits ◽  
Mutant P53 ◽  
Genome Maintenance ◽  
The Guardian

The p53 protein has been extensively studied for its capacity to prevent proliferation of cells with a damaged genome. Surprisingly, however, our recent analysis of mice expressing a hyperactive mutant p53 that lacks the C-terminal domain revealed that increased p53 activity may alter genome maintenance. We showed that p53 downregulates genes essential for telomere metabolism, DNA repair, and centromere structure and that a sustained p53 activity leads to phenotypic traits associated with dyskeratosis congenita and Fanconi anemia. This downregulation is largely conserved in human cells, which suggests that our findings could be relevant to better understand processes involved in bone marrow failure as well as aging and tumor suppression.

scholarly journals Oxidative stress, genomic features and DNA repair in frail elderly: A systematic review

2017 ◽  
Vol 37 ◽  
pp. 1-15 ◽  
Author(s):  
María Sánchez-Flores ◽  
Diego Marcos-Pérez ◽  
Solange Costa ◽  
João Paulo Teixeira ◽  
Stefano Bonassi ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Systematic Review ◽  
Dna Repair ◽  
Frail Elderly ◽  
Genomic Features

scholarly journals Recombination-Based Telomere Maintenance Is Dependent on Tel1-MRN and Rap1 and Inhibited by Telomerase, Taz1, and Ku in Fission Yeast

2007 ◽  
Vol 28 (5) ◽  
pp. 1443-1455 ◽  
Author(s):  
Lakxmi Subramanian ◽  
Bettina A. Moser ◽  
Toru M. Nakamura
Keyword(s):  
Dna Repair ◽  
Fission Yeast ◽  
Catalytic Subunit ◽  
Telomere Maintenance ◽  
Yeast Cells ◽  
Eukaryotic Cells ◽  
Checkpoint Kinase ◽  
Telomere Binding Protein ◽  
Evolutionarily Conserved ◽  
Linear Chromosomes

ABSTRACT Fission yeast cells survive loss of the telomerase catalytic subunit Trt1 (TERT) through recombination-based telomere maintenance or through chromosome circularization. Although trt1Δ survivors with linear chromosomes can be obtained, they often spontaneously circularize their chromosomes. Therefore, it was difficult to establish genetic requirements for telomerase-independent telomere maintenance. In contrast, when the telomere-binding protein Taz1 is also deleted, taz1Δ trt1Δ cells are able to stably maintain telomeres. Thus, taz1Δ trt1Δ cells can serve as a valuable tool in understanding the regulation of telomerase-independent telomere maintenance. In this study, we show that the checkpoint kinase Tel1 (ATM) and the DNA repair complex Rad32-Rad50-Nbs1 (MRN) are required for telomere maintenance in taz1Δ trt1Δ cells. Surprisingly, Rap1 is also essential for telomere maintenance in taz1Δ trt1Δ cells, even though recruitment of Rap1 to telomeres depends on Taz1. Expression of catalytically inactive Trt1 can efficiently inhibit recombination-based telomere maintenance, but the inhibition requires both Est1 and Ku70. While Est1 is essential for recruitment of Trt1 to telomeres, Ku70 is dispensable. Thus, we conclude that Taz1, TERT-Est1, and Ku70-Ku80 prevent telomere recombination, whereas MRN-Tel1 and Rap1 promote recombination-based telomere maintenance. Evolutionarily conserved proteins in higher eukaryotic cells might similarly contribute to telomere recombination.

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