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Improved methods for functional neuronal imaging with genetically encoded voltage indicators

Voltage imaging has the potential to revolutionise neuronal physiology, enabling high temporal and spatial resolution monitoring of sub- and supra-threshold activity in genetically defined cell classes. Before this goal is reached a number of challenges must be overcome: novel optical, genetic, and experimental techniques must be combined to deal with voltage imaging’s unique difficulties. In this thesis three techniques are applied to genetically encoded voltage indicator (GEVI) imaging. First, I describe a multifocal two-photon microscope and present a novel source localisation control and reconstruction algorithm to increase scattering resistance in functional imaging. I apply this microscope to image population and single-cell voltage signals from voltage sensitive fluorescent proteins in the first demonstration of multifocal GEVI imaging. Second, I show that a recently described genetic technique that sparsely labels cortical pyramidal cells enables single-cell resolution imaging in a one-photon widefield imaging configuration. This genetic technique allows simple, high signal-to-noise optical access to the primary excitatory cells in the cerebral cortex. Third, I present the first application of lightfield microscopy to single cell resolution neuronal voltage imaging. This technique enables single-shot capture of dendritic arbours and resolves 3D localised somatic and dendritic voltage signals. These approaches are finally evaluated for their contribution to the improvement of voltage imaging for physiology.Open Acces

We Know Too Little about Parasitoid Wasp Distributions to Draw Any Conclusions about Latitudinal Trends in Species Richness, Body Size and Biology

Much has been written about latitudinal trends in parasitoid diversity and biology, though it is widely recognised that they are a comparatively poorly known group. Here I show that for both braconid and ichneumonid wasps there are highly significant relationships between body size and the mean recorded latitude of species. Numbers of species per genus (surrogates of clades) peaks in the temperate zone for both families contrasting with data from the virtually complete inventories for mammals, birds and monocot plants, suggesting massive under-description of tropical parasitoid faunas. If the ichneumonoids may be expected to show similar trends to mammals, birds and other groups, the implication is that taxonomic work both in terms of active generic revisions, but also likely, the collecting and processing of museum specimens, and selection of taxa for revision, is woefully inadequate to allow latitudinal patterns in biology to be analysed

A new neotropical braconine (Hym., Braconidae) parasitic on Bruchidae (Col.)

Un genre nouveau, #Cyclaulacidea gen. n. (espèce-type #C. bruchivorus sp. n.) est décrit du Pérou et illustré. Il s'agit d'un parasitoïde des stades préimaginaux de la bruche #Caryoborus serripes, qui attaque les fruits comestibles de plusieurs palmiers appartenant au genre #Astrocaryum. Des données biologiques concernant les palmiers, la bruche et le parasitoïde sont fournies. (Résumé d'auteur

Complex Evolutionary History of Primate LentiviralvprGenes

AbstractVpx and Vpr are homologous proteins encoded by the human and simian immunodeficiency viruses. Vpr is encoded by each of the five primate lentiviral groups, whereas Vpx is restricted to members of the HIV-2 group. A recent report has proposed that thevpxgene was probably acquired from an ancestral member of the SIVagm group by nonhomologous recombination. Here, we suggest that this transfer event was more likely to have occurred via homologous recombination within the 3′ region of another gene,vif.Furthermore, phylogenetic analysis strongly suggests that there have been at least two other horizontal transfer events involving these genes: the first between ancestral members of the HIV-1 and HIV-2 groups, and the second between viruses isolated from the vervet and tantalus subspecies of African green monkey (Cercopithecus aethiopsssp)

The evolution of antennal courtship in diplazontine parasitoid wasps (Hymenoptera, Ichneumonidae, Diplazontinae)

<p>Abstract</p> <p>Background</p> <p>As predicted by theory, traits associated with reproduction often evolve at a comparatively high speed. This is especially the case for courtship behaviour which plays a central role in reproductive isolation. On the other hand, courtship behavioural traits often involve morphological and behavioural adaptations in both sexes; this suggests that their evolution might be under severe constraints, for instance irreversibility of character loss. Here, we use a recently proposed method to retrieve data on a peculiar courtship behavioural trait, i.e. antennal coiling, for 56 species of diplazontine parasitoid wasps. On the basis of a well-resolved phylogeny, we reconstruct the evolutionary history of antennal coiling and associated morphological modifications to study the mode of evolution of this complex character system.</p> <p>Results</p> <p>Our study reveals a large variation in shape, location and ultra-structure of male-specific modifications on the antennae. As for antennal coiling, we find either single-coiling, double-coiling or the absence of coiling; each state is present in multiple genera. Using a model comparison approach, we show that the possession of antennal modifications is highly correlated with antennal coiling behaviour. Ancestral state reconstruction shows that both antennal modifications and antennal coiling are highly congruent with the molecular phylogeny, implying low levels of homoplasy and a comparatively low speed of evolution. Antennal coiling is lost on two independent occasions, and never reacquired. A zero rate of regaining antennal coiling is supported by maximum parsimony, maximum likelihood and Bayesian approaches.</p> <p>Conclusions</p> <p>Our study provides the first comparative evidence for a tight correlation between male-specific antennal modifications and the use of the antennae during courtship. Antennal coiling in Diplazontinae evolved at a comparatively low rate, and was never reacquired in any of the studied taxa. This suggests that the loss of antennal coiling is irreversible on the timescale examined here, and therefore that evolutionary constraints have greatly influenced the evolution of antennal courtship in this group of parasitoid wasps. Further studies are needed to ascertain whether the loss of antennal coiling is irreversible on larger timescales, and whether evolutionary constraints have influenced courtship behavioural traits in a similar way in other groups.</p

Response to: Losina E. Why past research successes do not translate to clinical reality: gaps in evidence on exercise program efficiency. Osteoarthritis and Cartilage 2019;27:1-2

Letter to the editor

Attitudes, beliefs and physical activity in older adults with knee pain

Knee pain in older adults is common and often disabling, with the majority of knee pain in adults over the age of 45 being attributed to osteoarthritis (OA). Regular physical activity and exercise are recommended for all older adults with knee pain and are associated with reduced pain and improved function. However, physical activity levels are low in this population and there is uncertainty regarding its long-term safety, whether change in physical activity level is associated with future pain and function, and the relationship between attitudes and beliefs about physical activity and physical activity level. This thesis addressed these research questions. A systematic review of safety outcomes from 49 published studies found exercise was safe for the majority of older adults with knee pain, although most evidence related to low impact, moderate cardiovascular intensity exercise. Secondary data analysis of an exercise randomised controlled trial for older adults with knee pain (n=514) did not find an association between change in physical activity level between baseline and three months and clinical outcome at either three or six months. Secondary cross-sectional data analysis, using baseline data from the same trial and a community survey of older adults with knee pain (n=611), found that a number of scales measuring attitudes and beliefs about physical activity were associated with physical activity level in multivariable models. Positive outcome expectations, self-efficacy for exercise, kinesiophobia and a composite scale measuring physical activity attitude themes were associated with physical activity level. Further longitudinal analysis from the trial showed that positive outcome expectations and self-efficacy for exercise remained associated with future physical activity level at three and six months within multivariable models whilst negative outcome expectations were not. The original thesis findings have contributed to a better understanding of attitudes, beliefs and physical activity in older adults with knee pain

Two methods of assessing the mortality factors affecting the larvae and pupae of Cameraria ohridella in the leaves of Aesculus hippocastanum in Switzerland and Bulgaria

The horse-chestnut leaf miner, Cameraria ohridella, is an invasive alien species defoliating horse-chestnut, a popular ornamental tree in Europe. This paper presents quantitative data on mortality factors affecting larvae and pupae of the leaf miner in Switzerland and Bulgaria, both in urban and forest environments. Two sampling methods were used and compared: a cohort method, consisting of the surveying of pre-selected mines throughout their development, and a grab sampling method, consisting of single sets of leaves collected and dissected at regular intervals. The total mortality per generation varied between 14 and 99%. Mortality was caused by a variety of factors, including parasitism, host feeding, predation by birds and arthropods, plant defence reaction, leaf senescence, intra-specific competition and inter-specific competition with a fungal disease. Significant interactions were found between mortality factors and sampling methods, countries, environments and generation. No mortality factor was dominant throughout the sites, generations and methods tested. Plant defence reactions constituted the main mortality factor for the first two larval stages, whereas predation by birds and arthropods and parasitism were more important in older larvae and pupae. Mortality caused by leaf senescence was often the dominant mortality factor in the last annual generation. The cohort method detected higher mortality rates than the grab sampling method. In particular, mortality by plant defence reaction and leaf senescence were better assessed using the cohort method, which is, therefore, recommended for life table studies on leaf miner