About
42
Publications
10,710
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
1,026
Citations
Introduction
Skills and Expertise
Additional affiliations
October 2006 - present
April 1998 - October 2006
Publications
Publications (42)
Environmental factors and individual attributes, and their interactions, impact survival, growth and reproduction of an individual throughout its life. In the clonal rotifer Brachionus, low food conditions delay reproduction and extend lifespan. This species also exhibits maternal effect senescence; the offspring of older mothers have lower surviva...
The Midwest Aging Consortium (MAC) has emerged as a critical collaborative initiative aimed at advancing our understanding of aging and developing strategies to combat the rising prevalence of age-related diseases. Founded in 2019, MAC brings together researchers from various disciplines and institutions across the Midwestern United States to foste...
Across diverse taxa, offspring from older mothers have decreased lifespan and fitness. Little is known about the extent to which maternal age effects vary among genotypes for a given species, however, except for studies of a few arthropod species. To investigate the presence and degree of intraspecific variability in maternal age effects, we compar...
Characterizing swimming behavior can provide a holistic assessment of the health, physiology and ecology of microfaunal species when done in conjunction with measuring other biological parameters. However, tracking and quantifying microfauna swimming behavior using existing automated tools is often difficult due to the animals' small size or transp...
Rotifers have been studied in the laboratory and field for over 100 years in investigations of microevolution, ecological dynamics, and ecotoxicology. In recent years, rotifers have emerged as a model system for modern studies of the molecular mechanisms of genome evolution, development, DNA repair, aging, life history strategy, and desiccation tol...
Sequencing of reduced representation libraries enables genotyping of many individuals for population genomic studies. However, high amounts of DNA are required, and the method cannot be applied directly on single cells, preventing its use on most microbes. We developed and implemented the analysis of single amplified genomes (SAGs) followed by rest...
Across diverse taxa, offspring from older mothers have decreased lifespan and fitness. Little is known about whether such maternal age effects vary among genotypes for a given species, however. We compared maternal age effects among four strains of rotifers in the Brachionus plicatilis species complex. For each strain, we measured lifespan, reprodu...
Rotifers have been studied in the laboratory and field for over 100 years and are an emerging modern model system for investigation of the molecular mechanisms of genome evolution, development, DNA repair, aging, life history strategy, and desiccation tolerance, and have a long been used in studies of microevolution, ecological dynamics, and ecotox...
Sex differences in aging occur in many animal species, and they include sex differences in lifespan, in the onset and progression of age‐associated decline, and in physiological and molecular markers of aging. Sex differences in aging vary greatly across the animal kingdom. For example, there are species with longer‐lived females, species where mal...
Variance among individuals in fitness components reflects both genuine heterogeneity between individuals and stochasticity in events experienced along the life cycle. Maternal age represents a form of heterogeneity that affects both the mean and the variance of lifetime reproductive output (LRO). Here, we quantify the relative contribution of mater...
Because every species has unique attributes relevant to understanding specific aspects of aging, using a diversity of study systems and a comparative biology approach for aging research has the potential to lead to novel discoveries applicable to human health. Monogonont rotifers, a standard model for studies of aquatic ecology, evolutionary biolog...
Significance
Maternal effect senescence, the decline in offspring quality with increasing maternal age, is common in animals despite its negative impact on fitness. To understand how maternal effect senescence might evolve, we built matrix population models to calculate selection gradients on survival and fertility as functions of maternal age. We...
Maternal effect senescence---a decline in offspring fitness with maternal age---has been demonstrated in a range of taxa, including humans. Despite decades of phenotypic studies, it remains unclear how maternal effect senescence impacts population structure or evolutionary fitness. To understand the impact of maternal effect senescence on populatio...
Serotonin (5-HT) is a key player in many physiological processes both in the adult organism and developing embryo. One of the mechanisms for 5-HT-mediated effects is covalent binding of 5-HT to the target proteins catalyzed by transglutaminases (serotonylation). Despite the implication in a variety of physiological processes, the involvement of ser...
Maternal age has a negative effect on offspring lifespan in a range of taxa and is hypothesized to influence the evolution of aging. However, the mechanisms of maternal age effects are unknown, and it remains unclear if maternal age alters offspring response to therapeutic interventions to aging. Here, we evaluate maternal age effects on offspring...
The taxonomy of the dinoflagellate cyst-based genus Votadinium has been in need of revision. This was accomplished here by integrating morphology, LSU rDNA sequences, and cyst wall composition analyses through micro-Fourier transform infrared spectroscopy. Three new species, Votadinium pontifossatum, V. rhomboideum and V. reidii, were described as...
Maternal age has a negative effect on offspring lifespan in a range of taxa and is hypothesized to influence the evolution of aging. However, the mechanisms of maternal age effects are unknown, and it remains unclear if maternal age alters offspring response to therapeutic interventions to aging. Here, we evaluate maternal age effects on offspring...
Lifespan extension under low temperature is well conserved across both endothermic and exothermic taxa, but the mechanism underlying this change in aging is poorly understood. Low temperature is thought to decrease metabolic rate, thus slowing the accumulation of cellular damage from reactive oxygen species, although recent evidence suggests involv...
Background
Understanding gene expression changes over lifespan in diverse animal species will lead to insights to conserved processes in the biology of aging and allow development of interventions to improve health. Rotifers are small aquatic invertebrates that have been used in aging studies for nearly 100 years and are now re-emerging as a modern...
Rotifers are microscopic cosmopolitan zooplankton used as models in ecotoxicological and aging studies due to their several advantages such as short lifespan, ease of culture, and parthenogenesis that enables clonal culture. However, caution is required when measuring their survival time as it is affected by maternal age and maternal feeding condit...
Comparative biogerontology has much to contribute to the study of aging. A broad range of aging rates has 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....
Table S1 Life span, fecundity and body size of mothers and offspring.
While many studies have focused on the detrimental effects of advanced maternal age and harmful prenatal environments on progeny, little is known about the role of beneficial non-Mendelian maternal inheritance on aging. Here, we report the effects of maternal age and maternal caloric restriction (CR) on the life span and health span of offspring fo...
Caloric restriction (CR) is cited as the most robust means of increasing lifespan across a range of taxa, yet there is a high degree of variability in the response to CR, both within and between species. To examine the intraspecific evolutionary conservation of lifespan extension by CR, we tested the effects of chronic caloric restriction (CCR) at...
We measured life span and fecundity of three reproductive modes in a clone of the monogonont rotifer Brachionus manjavacas subjected to chronic caloric restriction (CCR) over a range of food concentrations or to intermittent fasting (IF). IF increased
life span 50%–70% for all three modes, whereas CCR increased life span of asexual females derived...
Background
Chemically mediated prezygotic barriers to reproduction likely play an important role in speciation. In facultatively sexual monogonont rotifers from the Brachionus plicatilis cryptic species complex, mate recognition of females by males is mediated by the Mate Recognition Protein (MRP), a globular glycoprotein on the surface of females,...
The mate recognition protein (MRP) gene is a member of a family of extracellular matrix protein genes, called MRP Motif Repeat
(MMR) genes, with no known homologs. Two sets of MMR genes, designated MMR-A and MMR-B, were found in Brachionus manjavacas. MMR-B has previously been shown to encode the MRP in the Brachionus plicatilis species complex. MM...
Mate choice is of central importance to most animals, influencing population structure, speciation, and ultimately the survival of a species. Mating behavior of male brachionid rotifers is triggered by the product of a chemosensory gene, a glycoprotein on the body surface of females called the mate recognition pheromone. The mate recognition pherom...
A suite of morphological, histological, and molecular techniques was used to reveal for the first time division, sexuality, mandatory dormancy period of hypnozygotes, and identity of life-history stages of any Protoperidinium spp. In both Protoperidinium steidingerae and Protoperidinium depressum, asexual division occurred by eleutheroschisis withi...
Marine thecate heterotrophic dinoflagellates likely play an important role in the consumption of primary productivity and in the trophic structure of the plankton, yet we know little about these species. This thesis expanded our understanding of the autecology and evolutionary history of the Protoperidinium and diplopsalids. The distributions of Pr...
This study is the first detailed investigation of the diversity, distribution and potential grazing impacts of Protoperidinium spp. in relation to the hydrography and phytoplankton distributions off the southwestern coast of Ireland. In late July 2003, the area was well stratified, and the Irish Shelf Front was apparent as a strong salinity front o...
Large-subunit ribosomal DNA (LSU rDNA) gene sequences are frequently used to infer the phylogeny and species identity of organisms. The many copies of the LSU rDNA found in the genome are thought to be kept homogeneous by concerted evolution. In this study, we found high intraindividual, intraspecific and interspecific diversity in the D1-D6 region...
The genera Protoperidinium Bergh, Diplopsalis Bergh, and Preperidinium Mangin, comprised of species of marine, thecate, heterotrophic dinoflagellates in the family Protoperidinaceae Balech, have had a confused taxonomic history. To elucidate the validity of morphological groupings within the Protoperidinium and diplopsalids, and to determine the ev...
Alexandrium ostenfeldii is a thecate, mixotrophic dinoflagellate recently linked to a novel suite of toxins called spirolides. This study provides the first description of the regional distribution of A. ostenfeldii in the Gulf of Maine (GOM), and the first report and analysis of spirolide toxicity in A. ostenfeldii in waters south of Nova Scotia....
Three different molecular methods were used with traditional brightfield microscope techniques to enumerate the toxic dinoflagellate Alexandrium fundyense in samples collected in the Gulf of Maine in 1998, 2000, 2001, and 2003. Two molecular probes were used in fluorescent whole-cell (WC) microscopic assays: a large-subunit ribosomal RNA (LSU rRNA)...
Life cycle stages of the heterotrophic dinoflagellate Protoperidinium depressum were determined for a culture isolated from the west coast of Ireland. Division, sexuality, DNA content, gamete morphology, and identity of morphologically distinct life-history stages were revealed for the first time using a suite of morphological and molecular tools....
Fortytwo different dinoflagellate cyst types were found in recent sediment samples collected between July 1999September 2002 from 44 stations along the eastern coast of Russia. This represents the first survey of recent dinoflagellate cysts in Russian marine waters. Forty cysts were identified to the species level, representing 17 genera. The most...