Elevated homocysteine is associated with increased rates of epigenetic aging in a population with mild cognitive impairment.

Elevated plasma total homocysteine (tHcy) is associated with the development of Alzheimer's disease and other forms of dementia. In this study, we report the relationship between tHcy and epigenetic age in older adults with mild cognitive impairment from the VITACOG study. Epigenetic age and rate of aging (ROA) were assessed using various epigenetic clocks, including those developed by Horvath and Hannum, DNAmPhenoAge, and with a focus on Index, a new principal component-based epigenetic clock that, like DNAmPhenoAge, is trained to predict an individual's "PhenoAge." We identified significant associations between tHcy levels and ROA, suggesting that hyperhomocysteinemic individuals were aging at a faster rate. Moreover, Index revealed a normalization of accelerated epigenetic aging in these individuals following treatment with tHcy-lowering B-vitamins. Our results indicate that elevated tHcy is a risk factor for accelerated epigenetic aging, and this can be ameliorated with B-vitamins. These findings have broad relevance for the sizable proportion of the worldwide population with elevated tHcy.

Moving eDNA surveys onto land: Strategies for active eDNA aggregation to detect invasive forest insects.

The use of environmental DNA (eDNA) surveys to monitor terrestrial species has been relatively limited, with successful implementations still confined to sampling DNA from natural or artificial water bodies and soil. Sampling water for eDNA depends on proximity to or availability of water, whereas eDNA from soil is limited in its spatial scale due to the large quantities necessary for processing and difficulty in doing so. These challenges limit the widespread use of eDNA in several systems, such as surveying forests for invasive insects. We developed two new eDNA aggregation approaches that overcome the challenges of above-ground terrestrial sampling and eliminate the dependency on creating or utilizing pre-existing water bodies to conduct eDNA sampling. The first, "spray aggregation," uses spray action to remove eDNA from surface substrates and was developed for shrubs and other understorey vegetation, while the second, "tree rolling," uses physical transfer via a roller to remove eDNA from the surface of tree trunks and large branches. We tested these approaches by surveying for spotted lanternfly, Lycorma delicatula, a recent invasive pest of northeastern USA that is considered a significant ecological and economic threat to forests and agriculture. We found that our terrestrial eDNA surveys matched visual surveys, but also detected L. delicatula presence ahead of visual surveys, indicating increased sensitivity of terrestrial eDNA surveys over currently used methodology. The terrestrial eDNA approaches we describe can be adapted for use in surveying a variety of forest insects and represent a novel strategy for surveying terrestrial biodiversity.

Influence of invasion history on rapid morphological divergence across island populations of an exotic bird.

There is increasing evidence that exotic populations may rapidly differentiate from those in their native range and that differences also arise among populations within the exotic range. Using morphological and DNA-based analyses, we document the extent of trait divergence among native North American and exotic Hawaiian populations of northern cardinal (Cardinalis cardinalis). Furthermore, using a combination of historical records and DNA-based analyses, we evaluate the role of founder effects in producing observed trait differences. We measured and compared key morphological traits across northern cardinal populations in the native and exotic ranges to assess whether trait divergence across the Hawaiian Islands, where this species was introduced between 1929 and 1931, reflected observed variation across native phylogeographic clades in its native North America. We used and added to prior phylogenetic analyses based on a mitochondrial locus to identify the most likely native source clade(s) for the Hawaiian cardinal populations. We then used Approximate Bayesian Computation (ABC) to evaluate the role of founder effects in producing the observed differences in body size and bill morphology across native and exotic populations. We found cardinal populations on the Hawaiian Islands had morphological traits that diverged substantially across islands and overlapped the trait space of all measured native North American clades. The phylogeographic analysis identified the eastern North American clade (C. cardinalis cardinalis) as the most likely and sole native source for all the Hawaiian cardinal populations. The ABC analyses supported written accounts of the cardinal's introduction that indicate the original 300 cardinals shipped to Hawaii were simultaneously and evenly released across Hawaii, Kauai, and Oahu. Populations on each island likely experienced bottlenecks followed by expansion, with cardinals from the island of Hawaii eventually colonizing Maui unaided. Overall, our results suggest that founder effects had limited impact on morphological trait divergence of exotic cardinal populations in the Hawaiian archipelago, which instead reflect postintroduction events.

Global invasion network of the brown marmorated stink bug, Halyomorpha halys.

Human mediated transportation into novel habitats is a prerequisite for the establishment of non-native species that become invasive, so knowledge of common sources may allow prevention. The brown marmorated stink bug (BMSB, Halyomorpha halys) is an East Asian species now established across North America and Europe, that in the Eastern United States of America (US) and Italy is causing significant economic losses to agriculture. After US populations were shown to originate from Northern China, others have tried to source BMSB populations now in Canada, Switzerland, Italy, France, Greece, and Hungary. Due to selection of different molecular markers, however, integrating all the datasets to obtain a broader picture of BMSB's expansion has been difficult. To address this limitation we focused on a single locus, the barcode region in the cytochrome oxidase I mitochondrial gene, and analyzed representative BMSB samples from across its current global range using an Approximate Bayesian Computation approach. We found that China is the likely source of most non-native populations, with at least four separate introductions in North America and three in Europe. Additionally, we found evidence of one bridgehead event: a likely Eastern US source for the central Italy populations that interestingly share enhanced pest status.

Real-time PCR assay to detect brown marmorated stink bug, Halyomorpha halys (Stål), in environmental DNA.

BACKGROUND: Early detection before establishment and identification of key predators are time-honored strategies towards effective eradication or control of invasive species. The brown marmorated stink bug (BMSB), Halyomorpha halys, is a recent exotic pest of several important crops in North America and Europe. Resulting widespread applications of insecticides have countered years of careful integrated pest management and are leading to the resurgence of other agricultural pests. Environmental DNA (eDNA) has been used effectively to detect aquatic invasives. RESULTS: We developed a real-time PCR (qPCR) assay for BMSB in a conserved region of the ribosomal DNA interspacer 1 (ITS1). We validated this assay on worldwide populations of BMSB and tested its specificity and sensitivity against other US Pentatomidae species and on guano of big brown bat, Eptesicus fuscus, which we confirmed is a BMSB predator in New Jersey. We also detected BMSB DNA after rapid (and inexpensive) HotSHOT DNA extractions of soiled paper from cages briefly holding BMSB, as well as from discarded exuviae. CONCLUSION: Given the high sensitivity of our assay to BMSB environmental DNA (eDNA) in terrestrial samples, this tool should become a cost-effective approach for using eDNA to detect terrestrial invasive species and their key predators. © 2016 Society of Chemical Industry.