Glycerol extends lifespan of Brachionus manjavacas (Rotifera) and protects against stressors

AbstractDiet has profound effects on animal longevity and manipulation of nutrient sensing pathways is one of the primary interventions capable of lifespan extension. This often is done through caloric restriction (CR) and a variety of CR mimics have been identified that produce life extending effects without adhering to the rigorous CR dietary regimen. Glycerol is a dietary supplement capable mimicking CR by shifting metabolism away from glycolysis and towards oxidative phosphorylation. Glycerol supplementation has a number of beneficial effects, including lifespan extension, improved stress resistance, and enhanced locomotory and mitochondria activity in older age classes. Using rotifers as a model, we show that supplements of 150–300mM glycerol produced 40–50% extension of mean lifespan. This effect was produced by raising glycerol concentration only three times higher than its baseline concentration in rotifer tissues. Glycerol supplementation decreased rotifer reliance on glycolysis and reduced the pro-aging effects of glucose. Glycerol also acted as a chemical chaperone, mitigating damage by protein aggregation. Glycerol treatment improved rotifer swimming performance in older age classes and maintained more mitochondrial activity. Glycerol treatment provided increased resistance to starvation, heat, oxidation, and osmotic stress, but not UV stress. When glycerol was co-administered with the hexokinase inhibitor 2-deoxyglucose, the lifespan extending effect of glycerol was enhanced. Co-administration of glycerol with inhibitors like 2-deoxyglucose can lower their efficacious doses, thereby reducing their toxic side effects

Size and Distribution of Resting Eggs in a Natural Population of the Rotifer Brachionus plicatilis

Resting eggs of the rotifer Brachionus plicatilis were collected from the sediments of a brackish-water pond near Tampa, Florida. These core samples were examined for resting egg density and size. Resting egg density decreased exponentially from the surface down to 7 cm in the sediments at all stations, with depth in the sediments accounting for 42.3% of the total variance. The maximum resting egg density recorded was 194 RE/cm3 with no significant differences in density among stations. Resting eggs were found to be significantly larger in the top 2 cm of sediment than resting eggs from deeper in the sediments. These data are discussed with regard to other work on resting egg densities in natural populations. Hypotheses are offered to explain the observed decrease in resting egg size with depth in sediments

Size and Distribution of Resting Eggs in a Natural Population of the Rotifer Brachionus plicatilis

Resting eggs of the rotifer Brachionus plicatilis were collected from the sediments of a brackish-water pond near Tampa, Florida. These core samples were examined for resting egg density and size. Resting egg density decreased exponentially from the surface down to 7 cm in the sediments at all stations, with depth in the sediments accounting for 42.3% of the total variance. The maximum resting egg density recorded was 194 RE/cm3 with no significant differences in density among stations. Resting eggs were found to be significantly larger in the top 2 cm of sediment than resting eggs from deeper in the sediments. These data are discussed with regard to other work on resting egg densities in natural populations. Hypotheses are offered to explain the observed decrease in resting egg size with depth in sediments

Rotifers as experimental tools for investigating aging

© 2014 The Author(s). This is an Open Access article. The definitive version was published in Invertebrate Reproduction & Development 59, Supple. 1 (2015): 5-10, doi:10.1080/07924259.2014.925516.Comparative biogerontology has much to contribute to the study of aging. A broad range of aging rates have evolved to meet environmental challenges, and understanding these adaptations can produce valuable insights into aging. The supra Phylum Lophotrochozoa is particularly understudied and has several groups that have intriguing patterns of aging. Members of the Lophotrochozoan phylum Rotifera are particularly useful for aging studies because cohort life tables can be conducted with them easily, and biochemical and genomic tools are available for examining aging mechanisms. This paper reviews a variety of caloric restriction (CR) regimens, small molecule inhibitors, and dietary supplements that extend rotifer lifespan, as well as important interactions between CR and genotype, antioxidant supplements, and TOR and jun-N-terminal kinase (JNK) pathways, and the use of RNAi to identify key genes involved in modulating the aging response. Examples of how rapamycin and JNK inhibitor exposure keeps mortality rates low during the reproductive phase of the life cycle are presented, and the ease of conducting life table experiments to screen natural products from red algae for life extending effects is illustrated. Finally, experimental evolution to produce longer-lived rotifer individuals is demonstrated, and future directions to determine the genetic basis of aging are discussed.We are grateful for the support of the National Institute of Aging, [grant number R01 AG037960-02] for this work and for a Postdoctoral Fellowship from the Ellison Medical Foundation/ American Federation for Aging Research to K. Gribble

シオミズツボワムシの増殖、両性生殖誘導及びサイズに与えるDMSO、NaOH、アセトン、エタノール添加の影響

Dimethyl sulfoxide (DMSO), sodium hydroxide (NaOH), acetone, and ethanol which are commonly used as solvents for steroid and thyroid hormones were tested for their effect on rotifer population growth, mictic female production, and body size. Each chemical was tested at 0.2%, 0.4%, 0.6%, 0.8% and 1% of the 5-ml Nannochloropsis oculata suspension (7×10⁶cells/ml). Initially, 5 rotifers each carrying one amictic egg were exposed in these concentrations at 25℃ in dark condition for 48 hours. Thereafter, rotifers were counted and transferred to a new culture medium without the chemical on day 2, 4, 6, and 8. Body size was measured on day 8. DMSO at 0.2% and 0.4% significantly increased rotifer population growth while 0.4, 0.6, 0.8, and 1% caused an increase in mictic female production. NaOH at 0.4% and 0.8% significantly increased population growth while 0.8% caused an increase in mictic female production. Acetone at 0.8% and 1% caused a decrease in population growth but it had no effect on mictic female production. Ethanol caused a decrease in population growth in all tested concentrations but it did not affect mictic female production. Body size of DMSO-, NaOH-, acetone-, or ethanol-treated rotifers was not significantly different from that of the control. Acetone may be used as a solvent at concentrations lower than 0.8.%, whereas DMSO and NaOH may be used as high as 1% without adverse effects. Ethanol caused adverse effects as low as 0.2% and is therefore not suitable as solvent in experiments with rotifer populations.不溶性のステロイドホルモンや重金属化合物等の溶剤として用いられる,ジメチルスルホオキシド,水酸化ナトリウム,アセトン,エチルアルコール(ワムシ培養への添加濃度は各々0.2, 0.6, 0.8, 1.0%)が,ワムシの生殖特性とサイズにどのような影響を与えるか検討した。0.2%および0.4%DMSOの添加によってワムシの増殖は促進され,一方0.4%以上の濃度では両性生殖誘導率が高くなった。NaOHを0.4, 0.8%添加するとワムシ増殖率は高くなった。エタノールの添加はいずれの濃度でもワムシの増殖を阻害したが,0.6%以下のアセトン添加ではワムシの生殖特性に対する影響はみられなかった。いずれの溶剤もワムシのサイズに影響を与えることはなかった。以上の結果はワムシのホルモン作用や毒性評価試験の生物材料としてワムシを使用する場合の基礎知見となるものである

Molecular evolution of the membrane associated progesterone receptor in the Brachionus plicatilis (Rotifera, Monogononta) species complex

Author Posting. © Springer, 2010. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Hydrobiologia 662 (2011): 99-106, doi:10.1007/s10750-010-0484-4.Many studies have investigated physiological roles of the membrane associated progesterone receptor (MAPR), but little is known of its evolution. Marked variations in response to exogenous progesterone have been reported for four brachionid rotifer species, suggesting differences in progesterone signaling and reception. Here we report sequence variation for the MAPR gene in the Brachionus plicatilis species complex. Phylogenetic analysis of this receptor is compared with relatedness based on cytochrome c oxidase subunit 1 sequences. Nonsynonymous to synonymous site substitution rate ratios, amino acid divergence, and variations in predicted phosphorylation sites are examined to assess evolution of the MAPR among brachionid clades.National Science Foundation grant BE/GenEn MCB-0412674E to TWS and DMW, and an NSF IGERT fellowship to HAS under DGE 0114400, supported this work

Fifteen species in one: deciphering the Brachionus plicatilis species complex (Rotifera, Monogononta) through DNA taxonomy

Understanding patterns and processes in biological diversity is a critical task given current and rapid environmental change. Such knowledge is even more essential when the taxa under consideration are important ecological and evolutionary models. One of these cases is the monogonont rotifer cryptic species complex Brachionus plicatilis, which is by far the most extensively studied group of rotifers, is widely used in aquaculture, and is known to host a large amount of unresolved diversity. Here we collate a dataset of previously available and newly generated sequences of COI and ITS1 for 1273 isolates of the B. plicatilis complex and apply three approaches in DNA taxonomy (i.e. ABGD, PTP, and GMYC) to identify and provide support for the existence of 15 species within the complex. We used these results to explore phylogenetic signal in morphometric and ecological traits, and to understand correlation among the traits using phylogenetic comparative models. Our results support niche conservatism for some traits (e.g. body length) and phylogenetic plasticity for others (e.g. genome size)

Levels of DNA methylation vary at CpG sites across the BRCA1 promoter, and differ according to triple negative and "BRCA-like" status, in both blood and tumour DNA

Triple negative breast cancer is typically an aggressive and difficult to treat subtype. It is often associated with loss of function of the BRCA1 gene, either through mutation, loss of heterozygosity or methylation. This study aimed to measure methylation of the BRCA1 gene promoter at individual CpG sites in blood, tumour and normal breast tissue, to assess whether levels were correlated between different tissues, and with triple negative receptor status, histopathological scoring for BRCA-like features and BRCA1 protein expression. Blood DNA methylation levels were significantly correlated with tumour methylation at 9 of 11 CpG sites examined (p<0.0007). The levels of tumour DNA methylation were significantly higher in triple negative tumours, and in tumours with high BRCA-like histopathological scores (10 of 11 CpG sites; p<0.01 and p<0.007 respectively). Similar results were observed in blood DNA (6 of 11 CpG sites; p<0.03 and 7 of 11 CpG sites; p<0.02 respectively). This study provides insight into the pattern of CpG methylation across the BRCA1 promoter, and supports previous studies suggesting that tumours with BRCA1 promoter methylation have similar features to those with BRCA1 mutations, and therefore may be suitable for the same targeted therapies

Erratum to: Methods for evaluating medical tests and biomarkers

[This corrects the article DOI: 10.1186/s41512-016-0001-y.]