The Potential of Food Fortification as an Enabler of More Environmentally Sustainable, Nutritionally Adequate Diets.

Policies encouraging shifts towards more plant-based diets can lead to shortfalls in micronutrients typically present in animal products (B-vitamins, vitamin D, calcium, iodine, iron, selenium, zinc, and long-chain omega-3 fatty acids). We modelled the effect of fortifying foods with these critical micronutrients, with the aim of achieving nutrition and sustainability goals, using food consumption data from Dutch adults (19-30 years). Three dietary scenarios were optimized for nutritional adequacy and 2030 greenhouse gas emissions (GHGE-2030) targets, respectively, with the fewest deviations from the baseline diet: (i) the current diet (mainly vitamin A- and D-fortified margarine, iodized bread, and some calcium- and vitamin D-fortified dairy alternatives and iron- and vitamin B12-fortified meat alternatives); (ii) all plant-based alternatives fortified with critical micronutrients; and (iii) fortified bread and oils. Optimizing the current diet for nutrition and GHGE-2030 targets reduced animal-to-plant protein ratios from ~65:35, to 33:67 (women) and 20:80 (men), but required major increases in legumes and plant-based alternatives. When fortifying all plant-based alternatives and, subsequently, bread and oil, smaller dietary changes were needed to achieve nutrition and GHGE-2030 targets. Fortifying food products with critical micronutrients, ideally with complementary education on plant-based foods, can facilitate the transition to healthier and more sustainable diets.

Haplaxius crudus (Hemiptera: Cixiidae) Transmits the Lethal Yellowing Phytoplasmas, 16SrIV, to Pritchardia pacifica Seem. & H.Wendl (Arecaceae) in Yucatan, Mexico.

Lethal yellowing (LY) affects several palm species in the Americas. It is caused by 16SrIV group phytoplasmas. In Florida (USA), LY was shown to be transmitted by the planthopper Haplaxius crudus ( Van Duzee ) (Hemiptera, Cixiidae) to different palm species, including Pritchardia pacifica Seem . & H. Wendl . (Arecaceae) in insect-proof cage experiments in the 1980s, a result that had never been reproduced later. LY has destroyed many coconut plantations as well as other palm species in the Caribbean and Mexico. In order to evaluate if H. crudus is a vector of LY phytoplasmas in Mexico, experiments were carried out in Yucatan (Mexico). Several H. crudus from palms infected by LY in the field were introduced into cages containing young P. pacifica palms. These insects were able to transmit 16SrIV group phytoplasmas to P. pacifica palms. According to DNA sequences comparative analysis, virtual restriction fragment length polymorphism, and phylogenetic analysis, the phytoplasmas detected in these infected P. pacifica were of subgroups A and D. All of ten P. pacifica palms infected with the subgroup D phytoplasmas developed symptoms of LY and died, whereas only one of two palms infected with subgroup A developed LY symptoms and died. This is the first time, more than 30 years later, that the role of H. crudus as a vector of LY is confirmed.

The effects of colonization, extinction and competition on co-existence in metacommunities.

1. The co-existence of competitors in heterogeneous landscapes depends on the processes of colonization, extinction and spatial scale. In this study, we explore the metapopulation dynamics of competitive interactions. 2. Rather than simply evaluating the outcome of interspecific competition in the traditional manner, we focus on both the local population dynamic effects and the regional metapopulation processes affecting species co-existence. 3. We develop a theoretical model of regional co-existence to generate a set of predictions on the patterns of colonization necessary for co-existence and the regional processes that can lead to competitive exclusion. We empirically test these predictions using metacommunity microcosms of the interaction between two bruchid beetles (Callosobruchus chinensis, Callosobruchus maculatus). 4. Using well-replicated time series of the interaction between the bruchids and statistical methods of model fitting, we show how the qualitative and quantitative pattern of interspecific competition between the bruchid beetles is shaped by the structure of the metacommunity. 5. In unlimited dispersal metacommunities, the global exclusion of the inferior competitor is shown to be influenced more by the processes associated with extinction rather than low colonization ability. In restricted dispersal metacommunities, we show how the co-existence of competitors in a spatially heterogeneous habitat (patches connected through limited dispersal) is affected by Allee effects and life-history [colonization (dispersal) - competition] trade-offs.

Non-associative learning in larval zebrafish.

Habituation, where a response is reduced when exposed to a continuous stimulus is one of the simplest forms of non-associative learning and has been shown in a number of organisms from sea slugs to rodents. However, very little has been reported in the zebrafish, a model that is gaining popularity for high-throughput compound screens. Furthermore, since most of the studies involving learning and memory in zebrafish have been conducted in adults, we sought to determine if zebrafish larvae could display non-associative learning and whether it could be modulated by compounds identified in previous rodent studies. We demonstrated that zebrafish larvae (7 days post fertilization) exhibit iterative reduction in a startle response to a series of acoustic stimuli. Furthermore, this reduction satisfied criteria for habituation: spontaneous recovery, more rapid reductions in startle to shorter intertrial intervals and dishabituation. We then investigated the pathways mediating this behavior using established compounds in learning and memory. Administration of rolipram (PDE4 inhibitor), donepezil (acetylcholinesterase inhibitor), and memantine (N-methyl-D-aspartic acid (NMDA) receptor antagonist) all increased the acoustic startle response and decreased habituation in the larvae, similar to previous rodent studies. Further studies demonstrated that NMDA blocked the memantine response and the effect of donepezil was blocked by mecamylamine but not atropine suggesting that the donepezil response was mediated by nicotinic rather than muscarinic receptors. Zebrafish larvae possess numerous advantages for medium to high-throughput screening; the model described herein therefore offers the potential to screen for additional compounds for further study on cognition function.