97 research outputs found

    Invasive floating water weeds – killing life and commerce

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    Weeds by definition are plants that grow in the wrong place. When their seeds or other plant parts are transported to other regions where their natural enemies are absent, they can multiply unhindered. Indigenous plants, especially those that are adapted for invading disturbed areas, can also become weeds. The first category is a particularly good target for classical biological control. Insects, mites and micro-organisms that feed on them are imported from their original area and released against the new invader. Against indigenous plants however, biological control is far less promising. By the end of 1980s, many of the water bodies in West Africa were invaded by alien plant species considered to be among the world’s worst aquatic weeds: water hyacinth Eichhornia crassipes, water lettuce Pistia stratiotes, and water fern Salvinia molesta. They were accidentally or deliberately introduced as ornamentals or for use in aquariums from their native range South America to many parts of the world where they have become invasive

    Somatostatin interneurons activated by 5-HT2A receptor suppress slow oscillations in medial entorhinal cortex

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    Serotonin (5-HT) is one of the major neuromodulators present in the mammalian brain and has been shown to play a role in multiple physiological processes. The mechanisms by which 5-HT modulates cortical network activity, however, are not yet fully understood. We investigated the effects of 5-HT on slow oscillations (SOs), a synchronized cortical network activity universally present across species. SOs are observed during anesthesia and are considered to be the default cortical activity pattern. We discovered that 3,4-methylenedioxymethamphetamine (MDMA) and fenfluramine, two potent 5-HT releasers, inhibit SOs within the entorhinal cortex (EC) in anesthetized mice. Combining opto- and pharmacogenetic manipulations with in vitro electrophysiological recordings, we uncovered that somatostatin-expressing (Sst) interneurons activated by the 5-HT2A receptor (5-HT2AR) play an important role in the suppression of SOs. Since 5-HT2AR signaling is involved in the etiology of different psychiatric disorders and mediates the psychological effects of many psychoactive serotonergic drugs, we propose that the newly discovered link between Sst interneurons and 5-HT will contribute to our understanding of these complex topics

    RIM-BP2 primes synaptic vesicles via recruitment of Munc13-1 at hippocampal mossy fiber synapses

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    All synapses require fusion-competent vesicles and coordinated Ca(2+)-secretion coupling for neurotransmission, yet functional and anatomical properties are diverse across different synapse types. We show that the presynaptic protein RIM-BP2 has diversified functions in neurotransmitter release at different central murine synapses and thus contributes to synaptic diversity. At hippocampal pyramidal CA3-CA1 synapses, RIM-BP2 loss has a mild effect on neurotransmitter release, by only regulating Ca(2+)-secretion coupling. However, at hippocampal mossy fiber synapses, RIM-BP2 has a substantial impact on neurotransmitter release by promoting vesicle docking/priming and vesicular release probability via stabilization of Munc13-1 at the active zone. We suggest that differences in the active zone organization may dictate the role a protein plays in synaptic transmission and that differences in active zone architecture is a major determinant factor in the functional diversity of synapses

    Food Poverty and Christianity in Britain: A Theological Re-assessment

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    The Christian response to food poverty in Britain has generally been two-fold. Foodbanks have become synonymous with Christianity and exemplify its charitable ethos. However, Christian churches have also called for social justice so that people can buy food in the normal way. Both responses are theologically problematic. The idea of foodbank is borne of a privileged theology that celebrates charitable giving, despite the humiliation it invites on recipients. Although social justice approaches originate in human rights discourse, the location of these rights in food consumerism means that it is equally privileged. Drawing on contextual and liberation theology, as well as ideas from radical orthodoxy, I argue that food poverty is better understood when we assign epistemological privilege to the poor. This leads me to advocate an alternative Christian response to food poverty
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