Variation in a host-epiphyte relationship along a wave exposure gradient

The red alga Polysiphonia lanosa (L ) Tandy is an obligate epiphyte that primarily occurs on the fucoid brown algal basiphyte Ascophyllum nodosum (L) Le Jolis In the present study we examine how epiphytic interactions between P lanosa and A nodosum vary along a wave exposure gradient within the southern Gulf of Maine, USA P lanosa was most dense on protected shores, however because the stature of P lanosa was greater on exposed than on sheltered shores, greater biomass occurred In exposed habitats Epiphytlc P lanosa pnmanly attached to inlured vegetative bssue at exposed sites, while ~ t osc currence was primarily receptacular at sheltered sites A significantly stronger correlation was found between host receptacle abundance and epiphyte abundance at a protected low than an exposed site As a result, the distribution of epiphytes along the host S stlpe vanes at different sites We suggest that changes in the distribution and abundance of P lanosa across this wave exposure gradient are highly influenced by vanations in the distribution and persistence of suitable attachment sites on the host plant Because both the quantity and quality of attachment sites vanes w t h exposure, we hypothesize that d~fferenpt rocesses limit or de t e rm~neP lanosa populations in different locations In protected sites P lanosa may be limited by the presence of adequate substrata (inlured bssue and lateral pits) where successful recruitment may occur By contrast at exposed sites the supply of P lanosa sporelings, rather than quantity of appropnate substrata, may limlt population size

REGULATORY ROLE OF OX22HIGH T-CELLS IN MERCURY-INDUCED AUTOIMMUNITY IN THE BROWN NORWAY RAT

The monoclonal antibody OX22 defines a functional split within CD4+ T cells in the rat, with OX22high cells mainly producing interleukin 2 (IL-2) and interferon γ and responsible for delayed-type hypersensitivity responses, and OX22low cells mainly producing IL-4 and -5 and responsible for providing B cell help. There are reciprocal interactions between OX22high and OX22low cells, and it has been suggested that the OX22low subset has a role in the prevention of autoimmunity. We have used OX22 in vivo to define the role of these subsets in mercuric chloride-induced autoimmunity in the Brown Norway rat. In this model, there is polyclonal B cell activation and animals develop widespread tissue injury. Treatment of thymectomized animals with OX22 led to a profound reduction in the number of OX22high T cells in the peripheral blood. OX22-treated animals consistently developed more severe tissue injury than controls given an irrelevant antibody of the same isotype. Control animals pretreated with broad spectrum antimicrobial drugs showed milder tissue injury, but this protective effect of antimicrobials was lost in OX22-treated animals. Transfer of naive T cells to OX22-treated animals provided protection, but if T cells were depleted in vitro of OX22high cells before transfer, this effect was lost. These data provide evidence for a protective immunoregulatory role for OX22high T cells in mercuric chloride-induced autoimmunity.link_to_subscribed_fulltex

Distribution, morphology, and genetic affinities of dwarf embedded Fucus populations from the Northwest Atlantic Ocean

Dwarf embedded Fucus populations in the Northwest Atlantic Ocean are restricted to the upper intertidal zone in sandy salt marsh environments; they lack holdfasts and are from attached parental populations of F. spiralis or F. spiralis x F. vesiculosus hybrids after breakage and entanglement with halophytic marsh grasses. Dwarf forms are dichotomously branched, flat, and have a mean overall length and width of 20.3 and 1.3 mm, respectively. Thus, they are longer than Irish (mean 9.3 mm) and Alaskan (mean 15.0 mm) populations identified as F cottonii. Reciprocal transplants of different Fucus taxa in a Maine salt marsh confirm that F spiralis can become transformed into dwarf embedded thalli within the high intertidal zone, while the latter can grow into F. s. ecad lutarius within the mid intertidal zone. Thus, vertical transplantation can modify fucoid morphology and result in varying ecads. Microsatellite markers indicate that attached F spiralis and F vesiculosus are genetically distinct, while dwarf forms may arise via hybridization between the two taxa. The ratio of intermediate to species-specific-genotypes decreased with larger thalli. Also, F s. ecad lutarius consists of a mixture of intermediate and pure genotypes, while dwarf thalli show a greater frequency of hybrids

A Likelihood-Free Inference Framework for Population Genetic Data using Exchangeable Neural Networks

An explosion of high-throughput DNA sequencing in the past decade has led to a surge of interest in population-scale inference with whole-genome data. Recent work in population genetics has centered on designing inference methods for relatively simple model classes, and few scalable general-purpose inference techniques exist for more realistic, complex models. To achieve this, two inferential challenges need to be addressed: (1) population data are exchangeable, calling for methods that efficiently exploit the symmetries of the data, and (2) computing likelihoods is intractable as it requires integrating over a set of correlated, extremely high-dimensional latent variables. These challenges are traditionally tackled by likelihood-free methods that use scientific simulators to generate datasets and reduce them to hand-designed, permutation-invariant summary statistics, often leading to inaccurate inference. In this work, we develop an exchangeable neural network that performs summary statistic-free, likelihood-free inference. Our framework can be applied in a black-box fashion across a variety of simulation-based tasks, both within and outside biology. We demonstrate the power of our approach on the recombination hotspot testing problem, outperforming the state-of-the-art.Comment: 9 pages, 8 figure

Digitization of multistep organic synthesis in reactionware for on-demand pharmaceuticals

Chemical manufacturing is often done at large facilities that require a sizable capital investment and then produce key compounds for a finite period. We present an approach to the manufacturing of fine chemicals and pharmaceuticals in a self-contained plastic reactionware device. The device was designed and constructed by using a chemical to computer-automated design (ChemCAD) approach that enables the translation of traditional bench-scale synthesis into a platform-independent digital code. This in turn guides production of a three-dimensional printed device that encloses the entire synthetic route internally via simple operations. We demonstrate the approach for the γ-aminobutyric acid receptor agonist, (±)-baclofen, establishing a concept that paves the way for the local manufacture of drugs outside of specialist facilities

The genomic footprint of social stratification in admixing American populations.

Cultural and socioeconomic differences stratify human societies and shape their genetic structure beyond the sole effect of geography. Despite mating being limited by sociocultural stratification, most demographic models in population genetics often assume random mating. Taking advantage of the correlation between sociocultural stratification and the proportion of genetic ancestry in admixed populations, we sought to infer the former process in the Americas. To this aim, we define a mating model where the individual proportions of the genome inherited from Native American, European, and sub-Saharan African ancestral populations constrain the mating probabilities through ancestry-related assortative mating and sex bias parameters. We simulate a wide range of admixture scenarios under this model. Then, we train a deep neural network and retrieve good performance in predicting mating parameters from genomic data. Our results show how population stratification, shaped by socially constructed racial and gender hierarchies, has constrained the admixture processes in the Americas since the European colonization and the subsequent Atlantic slave trade

Homeshare Scheme

Homeshare is a scheme in which older people – ‘Homeowners’ - provide an affordable home to young professionals or possibly students – ‘Homesharers’ - in exchange for help or support with everyday tasks (e.g. shopping and cleaning), and companionship. This pairing is intended to be mutually beneficial, whereby older people are provided with help and support to live independently and young people are offered a much needed home. There are similar schemes in London, but nothing like this is currently in place in Leeds. This report presents findings from a research project conducted in Leeds to investigate the demand for this service and the feasibility of this type of scheme. The research was funded by Leeds Metropolitan University and Leeds City Council

Dietary Patterns Associated with Alzheimer?s Disease and Related Chronic Disease Risk: A Review

The world’s population is growing older due to improved healthcare and nutrition. As a result, Alzheimer’s disease (AD) prevalence is rapidly increasing. The focus of the current research climate is shifting from understanding AD pathology and diagnosis to primary prevention and intervention strategies. Diet represents one potential intervention strategy accessible to all. Accumulating evidence suggests diet plays a major role in risk and development of AD and AD-related chronic diseases of the periphery like cardiovascular disease (CVD) and diabetes. This paper reviews studies that have explored the relationship between “a priori” dietary patterns, AD and AD-related chronic disease risk. The dietary patterns we will review are the healthy eating index, healthy diet indicator, recommended food score, and the Mediterranean diet (MeDi). Our review of the literature suggests a generally positive association between healthy diet patterns, AD and AD-related chronic disease risk; however the magnitude of the protective effect is modest in many studies. Consequently, we can only confidently conclude that the MeDi is associated with reduced AD risk, and further studies on the remaining indices need to be carried out. It is our opinion that a combination of dietary scores could predict overall dietary quality and chronic disease risk to a greater extent than one score individually. Analysis in multi-ethnic cohorts, investigating combinations of scores must be completed before firm conclusions can be reached on the ideal combination of scores. Obtaining further insight into the association between dietary patterns, AD and AD-related chronic disease risk may help in prioritizing public health efforts and provide a stronger basis for recommendations to improve dietary patterns