Age, sex, and strain differences in the aversive threshold to grid shock in the rat.

1969 ◽  
Vol 69 (2) ◽  
pp. 214-218 ◽  
Author(s):  
William P. Pare
Keyword(s):  
Strain Differences ◽  
Grid Shock

scholarly journals DNA methylation differs extensively between strains of the same geographical origin and changes with age in Daphnia magna

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Jack Hearn ◽  
Fiona Plenderleith ◽  
Tom J. Little
Keyword(s):  
Dna Methylation ◽  
Caloric Restriction ◽  
Daphnia Magna ◽  
Single Gene ◽  
Methylation Status ◽  
Strain Differences ◽  
Life History Trait ◽  
Food Level ◽  
Epigenetic Clock ◽  
Age Related

Abstract Background Patterns of methylation influence lifespan, but methylation and lifespan may also depend on diet, or differ between genotypes. Prior to this study, interactions between diet and genotype have not been explored together to determine their influence on methylation. The invertebrate Daphnia magna is an excellent choice for testing the epigenetic response to the environment: parthenogenetic offspring are identical to their siblings (making for powerful genetic comparisons), they are relatively short lived and have well-characterised inter-strain life-history trait differences. We performed a survival analysis in response to caloric restriction and then undertook a 47-replicate experiment testing the DNA methylation response to ageing and caloric restriction of two strains of D. magna. Results Methylated cytosines (CpGs) were most prevalent in exons two to five of gene bodies. One strain exhibited a significantly increased lifespan in response to caloric restriction, but there was no effect of food-level CpG methylation status. Inter-strain differences dominated the methylation experiment with over 15,000 differently methylated CpGs. One gene, Me31b, was hypermethylated extensively in one strain and is a key regulator of embryonic expression. Sixty-one CpGs were differentially methylated between young and old individuals, including multiple CpGs within the histone H3 gene, which were hypermethylated in old individuals. Across all age-related CpGs, we identified a set that are highly correlated with chronological age. Conclusions Methylated cytosines are concentrated in early exons of gene sequences indicative of a directed, non-random, process despite the low overall DNA methylation percentage in this species. We identify no effect of caloric restriction on DNA methylation, contrary to our previous results, and established impacts of caloric restriction on phenotype and gene expression. We propose our approach here is more robust in invertebrates given genome-wide CpG distributions. For both strain and ageing, a single gene emerges as differentially methylated that for each factor could have widespread phenotypic effects. Our data showed the potential for an epigenetic clock at a subset of age positions, which is exciting but requires confirmation.

scholarly journals Rat strain differences in pilocarpine-induced mouse killing

1976 ◽  
Vol 4 (1) ◽  
pp. 28-32 ◽  
Author(s):  
Patricia E. Gay ◽  
Russell C. Leaf
Keyword(s):  
Strain Differences ◽  
Mouse Killing ◽  
Rat Strain

scholarly journals Immersion vaccines against Yersinia ruckeri infection in rainbow trout: Comparative effects of strain differences

2021 ◽  
Author(s):  
He Yang ◽  
Ding Zhujin ◽  
Moonika H. Marana ◽  
Inger Dalsgaard ◽  
Jaafar Rzgar ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Strain Differences ◽  
Yersinia Ruckeri

scholarly journals Strain-Related Differences in Mouse Neonatal Hypoxia-Ischemia

2018 ◽  
Vol 40 (5-6) ◽  
pp. 490-496 ◽  
Author(s):  
R. Ann Sheldon ◽  
Christine Windsor ◽  
Donna M. Ferriero
Keyword(s):  
Brain Injury ◽  
Mouse Model ◽  
Strain Differences ◽  
Artery Occlusion ◽  
Carotid Artery Occlusion ◽  
Cresyl Violet ◽  
Posterior Cortex ◽  
Carotid Ligation ◽  
Hypoxia Ischemia ◽  
Cd1 Mice

Neonatal hypoxic-ischemic brain injury is commonly studied by means of the Vannucci procedure in mice or rats (unilateral common carotid artery occlusion followed by hypoxia). Previously, we modified the postnatal day 7 (P7) rat procedure for use in mice, and later demonstrated that genetic strain strongly influences the degree of brain injury in the P7 mouse model of hypoxia-ischemia (HI). Recently, the P9 or P10 mouse brain was recognized as the developmental equivalent of a term neonatal human brain, rather than P7. Consequently, the Vannucci procedure has again been modified, and a commonly used protocol employs 10% oxygen for 50 min in C57Bl/6 mice. Strain differences have yet to be described for the P9/P10 mouse model. In order to determine if the strain differences we previously reported in the P7 mouse model are present in the P9 model, we compared 2 commonly used strains, CD1 and C57Bl/6J, in both the P7 (carotid ligation [in this case, right] followed by exposure to 8% oxygen for 30 min) and P9 (carotid ligation [in this case left] followed by exposure to 10% oxygen) models of HI. Experiments using the P7 model were performed in 2001–2012 and those using the P9 model were performed in 2012–2016. Five to seven days after the HI procedure, mice were perfused with 4% paraformaldehyde, their brains were sectioned on a Vibratome (50 µm) and alternate sections were stained with Perl’s iron stain or cresyl violet. Brain sections were examined microscopically and scored for the degree of injury. Since brains in the P7 group had been scored previously with a slightly different system, they were reanalyzed using our current scoring system which scores injury in 11 regions: the anterior, middle, and posterior cortex; the anterior, middle, and posterior striatum; CA1, CA2, CA3, and the dentate gyrus of the hippocampus and thalamus, on a scale from 0 (none) to 3 (cystic infarct) for a total score of 0–33. Brains in the P9 group were scored with the same system. Given the same insult, the P7 CD1 mice had greater injury than the C57Bl/6J mice, which agrees with our previous findings. The P9 CD1 mice also had greater injury than the C57Bl/6J mice. This study confirms that CD1 mice are more susceptible to injury than C57Bl/6J mice and that strain selection is important when using mouse models of HI.

Congenic strains confirm aerobic running capacity quantitative trait loci on rat chromosome 16 and identify possible intermediate phenotypes

2007 ◽  
Vol 29 (1) ◽  
pp. 91-97 ◽  
Author(s):  
Justin A. Ways ◽  
Brian M. Smith ◽  
John C. Barbato ◽  
Ramona S. Ramdath ◽  
Krista M. Pettee ◽  
...  
Keyword(s):  
Quantitative Trait Loci ◽  
Quantitative Trait ◽  
Strain Differences ◽  
Proximal Portion ◽  
Chromosome 16 ◽  
Rat Strains ◽  
High Performing ◽  
Intermediate Phenotypes ◽  
Trait Loci ◽  
Inbred Rat

We previously identified two inbred rat strains divergent for treadmill aerobic running capacity (ARC), the low-performing Copenhagen (COP) and the high-performing DA rats, and used an F2(COP×DA) population to identify ARC quantitative trait loci (QTLs) on rat chromosome 16 (RNO16) and the proximal portion of rat chromosome 3 (RNO3). Two congenic rat strains were bred to further investigate these ARC QTLs by introgressing RNO16 and the proximal portion of RNO3 from DA rats into the genetic background of COP rats and were named COP.DA(chr 16) and COP.DA(chr 3), respectively. COP.DA(chr 16) rats had significantly greater ARC compared with COP rats (696.7 ± 38.2 m vs. 571.9 ± 27.5 m, P = 0.03). COP.DA(chr 3) rats had increased, although not significant, ARC compared with COP rats (643.6 ± 40.9 m vs. 571.9 ± 27.5 m). COP.DA(chr 16) rats had significantly greater subcutaneous abdominal fat, as well as decreased fasting triglyceride levels, compared with COP rats ( P < 0.05), indicating that genes responsible for strain differences in fat metabolism are also located on RNO16. While this colocalization of QTLs may be coincidental, it is also possible that these differences in energy balance may be associated with the superior running performance of COP.DA(chr 16) consomic rats.

Strain Differences In Broad Breasted Bronze Turkeys

1952 ◽  
Vol 8 (4) ◽  
pp. 290-291
Author(s):  
V. S. Asmundson
Keyword(s):  
Strain Differences
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