Ancient DNA evidence for the ecological globalization of cod fishing in medieval and post-medieval Europe.

Understanding the historical emergence and growth of long-range fisheries can provide fundamental insights into the timing of ecological impacts and the development of coastal communities during the last millennium. Whole-genome sequencing approaches can improve such understanding by determining the origin of archaeological fish specimens that may have been obtained from historic trade or distant water. Here, we used genome-wide data to individually infer the biological source of 37 ancient Atlantic cod specimens (ca 1050-1950 CE) from England and Spain. Our findings provide novel genetic evidence that eleventh- to twelfth-century specimens from London were predominantly obtained from nearby populations, while thirteenth- to fourteenth-century specimens were derived from distant sources. Our results further suggest that Icelandic cod was indeed exported to London earlier than previously reported. Our observations confirm the chronology and geography of the trans-Atlantic cod trade from Newfoundland to Spain starting by the early sixteenth century. Our findings demonstrate the utility of whole-genome sequencing and ancient DNA approaches to describe the globalization of marine fisheries and increase our understanding regarding the extent of the North Atlantic fish trade and long-range fisheries in medieval and early modern times.

Tumour cell death induced by the bulk photovoltaic effect of LiNbO3:Fe under visible light irradiation.

This work reports a pioneer application of the bulk photovoltaic effect in the biomedical field. Massive necrotic cell death was induced in human tumour cell cultures grown on a bulk photovoltaic material (iron-doped lithium niobate, LiNbO(3):Fe) after irradiation with visible light. Lethal doses (≈100% cell death) were obtained with low-intensity visible light sources (10-100 mW cm(-2) irradiances) and short exposure times of the order of minutes. The wavelength dependence to induce the lethal effect observed is consistent with that corresponding to the bulk photovoltaic effect generation in LiNbO(3):Fe. Necrosis also occurred when cultured tumour cells were exposed to LiNbO(3):Fe microparticles and visible light.

Detailed analysis of leucokinin-expressing neurons and their candidate functions in the Drosophila nervous system.

The distribution of leucokinin (LK) neurons in the central nervous system (CNS) of Drosophila melanogaster was described by immunolabelling many years ago. However, no detailed underlying information of the input or output connections of their neurites was then available. Here, we provide a more accurate morphological description by employing a novel LK-specific GAL4 line that recapitulates LK expression. In order to analyse the possible afferent and efferent neural candidates of LK neurons, we used this lk-GAL4 line together with other CNS-Gal4 lines, combined with antisera against various neuropeptides or neurotransmitters. We found four kinds of LK neurons in the brain. (1) The lateral horn neurons connect the antennal glomerula to the mushroom bodies. (2) The suboesophageal neurons connect the gustatory receptors to the suboesophageal ganglia and ventral nerve cord. (3) The anterior neurons innervate the corpus cardiacum of the ring gland but LK expression is surprisingly not detectable from the third instar onwards in these neurons. (4) A set of abdominal ganglion neurons connect to the dorsal median tract in larvae and send their axons to a segmental muscle 8. Thus, the methods employed in our study can be used to identify individual neuropeptidergic neurons and thereby characterize functional cues or developmental transformations in their differentiation.

Loss of glial lazarillo, a homolog of apolipoprotein D, reduces lifespan and stress resistance in Drosophila.

The vertebrate Apolipoprotein D (ApoD) is a lipocalin secreted from subsets of neurons and glia during neural development and aging . A strong correlation exists between ApoD overexpression and numerous nervous system pathologies as well as obesity, diabetes, and many forms of cancer . However, the exact relationship between the function of ApoD and the pathophysiology of these diseases is still unknown. We have generated loss-of-function Drosophila mutants for the Glial Lazarillo (GLaz) gene , a homolog of ApoD in the fruit fly, mainly expressed in subsets of adult glial cells. The absence of GLaz reduces the organism's resistance to oxidative stress and starvation and shortens male lifespan. The mutant flies exhibit a smaller body mass due to a lower amount of neutral lipids stored in the fat body. Apoptotic neural cell death increases in aged flies or upon paraquat treatment, which also impairs neural function as assessed by behavioral tests. The higher sensitivity to oxidative stress and starvation and the reduced fat storage revert to control levels when a GFP-GLaz fusion protein is expressed under the control of the GLaz natural promoter. Finally, GLaz mutants have a higher concentration of lipid peroxidation products, pointing to a lipid peroxidation protection or scavenging as the mechanism of action for this lipocalin. In agreement with Walker et al. (, in this issue of Current Biology), who analyze the effects of overexpressing GLaz, we conclude that GLaz has a protective role in stress situations and that its absence reduces lifespan and accelerates neurodegeneration.

Presynaptic Aß40 prevents synapse addition in the adult Drosophila neuromuscular junction.

Complexity in the processing of the Amyloid Precursor Protein, which generates a mixture of ßamyloid peptides, lies beneath the difficulty in understanding the etiology of Alzheimer's disease. Moreover, whether Aß peptides have any physiological role in neurons is an unresolved question. By expressing single, defined Aß peptides in Drosophila, specific effects can be discriminated in vivo. Here, we show that in the adult neuromuscular junction (NMJ), presynaptic expression of Aß40 hinders the synaptic addition that normally occurs in adults, yielding NMJs with an invariable number of active zones at all ages tested. A similar trend is observed for Aß42 at young ages, but net synaptic loss occurs at older ages in NMJs expressing this amyloid species. In contrast, Aß42arc produces net synaptic loss at all ages tested, although age-dependent synaptic variations are maintained. Inhibition of the PI3K synaptogenic pathway may mediate some of these effects, because western analyses show that Aß peptides block activation of this pathway, and Aß species-specific synaptotoxic effects persists in NMJs overgrown by over-expression of PI3K. Finally, individual Aß effects are also observed when toxicity is examined by quantifying neurodegeneration and survival. Our results suggest a physiological effect of Aß40 in synaptic plasticity, and imply different toxic mechanisms for each peptide species.

Blockade of the release of the neuropeptide leucokinin to determine its possible functions in fly behavior: chemoreception assays.

Previous studies have revealed leucokinin (LK) expression in the brain and ventral ganglion of Drosophila CNS. One pair of protocerebrum neurons located in the lateral horn area (LHLK) surrounds the peduncles of the mushroom bodies while two pairs of subesophageal neurons (SELKs) project extended processes to the tritocerebrum and through a cervical connection to the ventral ganglion. There, axons of eight or nine pairs of abdominal (ABLK) neurons leave the CNS through the abdominal nerves and processes connecting each other ipsilaterally and contralaterally. The neural functions of LK remain largely unknown, especially those related to Drosophila behavior. Here, we have studied the role of LK in olfactory and gustatory perception by keeping the LK neurons electrically silent through targeted expression of inward rectifier K(+) channels. In order to examine the effects of LK failure, we first analyzed the dehydration response, comparing the leucokinin-silent individuals with their parents as a control. Our results showed significant differences that demonstrate the effectiveness of the method. We then tested the olfactory behavioral response to a set of odorants over a range of concentrations in a T-maze paradigm in which flies were allowed to choose between the odorant and solvent compartments. The feeding preference assays were carried out on microplates in which flies were allowed to choose between two colored tastes. Our results show that the blockade of LK release alters both olfactory and gustatory responses, and are therefore evidence that this neuropeptide also modulates chemosensory responses through LHLK and SELK neurons.