Should Veterinary Practitioners Be Concerned about Acanthamoeba Keratitis?

When presented with an animal exhibiting signs of keratitis (inflammation of the cornea), such as impaired vision, mucoid discharges, redness, swelling, and corneal oedema, most veterinarians would think of bacteria, viruses, or fungi as the potential causative agent(s). However, evidence has arisen in recent years of a possible connection between the protozoan Acanthamoeba and keratitis in animals. Acanthamoeba infection is underdiagnosed, but potentially common, in animals. In view of the paucity of evidence regarding Acanthamoeba keratitis (AK) in animals, this review has been written to increase awareness of veterinary professionals of the potential threat associated with AK and to stimulate more studies into the extent of occurrence and clinical impact of AK in animals

dyschronic, a Drosophila Homolog of a Deaf-Blindness Gene, Regulates Circadian Output and Slowpoke Channels

Many aspects of behavior and physiology are under circadian control. In Drosophila, the molecular clock that regulates rhythmic patterns of behavior has been extensively characterized. In contrast, genetic loci involved in linking the clock to alterations in motor activity have remained elusive. In a forward-genetic screen, we uncovered a new component of the circadian output pathway, which we have termed dyschronic (dysc). dysc mutants exhibit arrhythmic locomotor behavior, yet their eclosion rhythms are normal and clock protein cycling remains intact. Intriguingly, dysc is the closest Drosophila homolog of whirlin, a gene linked to type II Usher syndrome, the leading cause of deaf-blindness in humans. Whirlin and other Usher proteins are expressed in the mammalian central nervous system, yet their function in the CNS has not been investigated. We show that DYSC is expressed in major neuronal tracts and regulates expression of the calcium-activated potassium channel SLOWPOKE (SLO), an ion channel also required in the circadian output pathway. SLO and DYSC are co-localized in the brain and control each other's expression post-transcriptionally. Co-immunoprecipitation experiments demonstrate they form a complex, suggesting they regulate each other through protein–protein interaction. Furthermore, electrophysiological recordings of neurons in the adult brain show that SLO-dependent currents are greatly reduced in dysc mutants. Our work identifies a Drosophila homolog of a deaf-blindness gene as a new component of the circadian output pathway and an important regulator of ion channel expression, and suggests novel roles for Usher proteins in the mammalian nervous system

A Low Concentration of Ethanol Impairs Learning but Not Motor and Sensory Behavior in Drosophila Larvae

Drosophila melanogaster has proven to be a useful model system for the genetic analysis of ethanol-associated behaviors. However, past studies have focused on the response of the adult fly to large, and often sedating, doses of ethanol. The pharmacological effects of low and moderate quantities of ethanol have remained understudied. In this study, we tested the acute effects of low doses of ethanol (∼7 mM internal concentration) on Drosophila larvae. While ethanol did not affect locomotion or the response to an odorant, we observed that ethanol impaired associative olfactory learning when the heat shock unconditioned stimulus (US) intensity was low but not when the heat shock US intensity was high. We determined that the reduction in learning at low US intensity was not a result of ethanol anesthesia since ethanol-treated larvae responded to the heat shock in the same manner as untreated animals. Instead, low doses of ethanol likely impair the neuronal plasticity that underlies olfactory associative learning. This impairment in learning was reversible indicating that exposure to low doses of ethanol does not leave any long lasting behavioral or physiological effects

Recurring Ethanol Exposure Induces Disinhibited Courtship in Drosophila

Alcohol has a strong causal relationship with sexual arousal and disinhibited sexual behavior in humans; however, the physiological support for this notion is largely lacking and thus a suitable animal model to address this issue is instrumental. We investigated the effect of ethanol on sexual behavior in Drosophila. Wild-type males typically court females but not males; however, upon daily administration of ethanol, they exhibited active intermale courtship, which represents a novel type of behavioral disinhibition. The ethanol-treated males also developed behavioral sensitization, a form of plasticity associated with addiction, since their intermale courtship activity was progressively increased with additional ethanol experience. We identified three components crucial for the ethanol-induced courtship disinhibition: the transcription factor regulating male sex behavior Fruitless, the ABC guanine/tryptophan transporter White and the neuromodulator dopamine. fruitless mutant males normally display conspicuous intermale courtship; however, their courtship activity was not enhanced under ethanol. Likewise, white males showed negligible ethanol-induced intermale courtship, which was not only reinstated but also augmented by transgenic White expression. Moreover, inhibition of dopamine neurotransmission during ethanol exposure dramatically decreased ethanol-induced intermale courtship. Chronic ethanol exposure also affected a male's sexual behavior toward females: it enhanced sexual arousal but reduced sexual performance. These findings provide novel insights into the physiological effects of ethanol on sexual behavior and behavioral plasticity

Molecular mechanisms of alcohol tolerance in the fruit fly

textLarge conductance calcium-activated potassium channels have been shown to be potentiated by physiologically relevant acute doses of ethanol. Here I show that ethanol sedation increased transcription of the slowpoke gene, which encodes a largeconductance calcium-activated potassium channel, in the nervous system of the fruit fly Drosophila melanogaster, six hours after ethanol sedation. Twenty-four hours after sedation, neural slowpoke expression was decreased. Sedation with ethanol also induced tolerance that developed within four hours of sedation and persisted for at least seven days. Drosophila lacking slowpoke expression only in the nervous system were unable to acquire tolerance and flies which over-expressed slowpoke displayed resistance to the sedating effects of ethanol. The expression of several other ion channels was also increased six hours after ethanol sedation, however no other ion channel mutant tested showed a deficit in the capacity to acquire tolerance. Wild-type and slowpoke mutant flies showed no differences in ethanol metabolism following ethanol sedation that could account for the tolerance or lack of it. Therefore the slowpoke gene appears to play a unique role in the phenomenon of tolerance.Institute for Cellular and Molecular Biolog

Posizionamento relativo tramite tecnologia UWB di un braccio automatico

La presente tesi si pone l'obiettivo di studiare le prestazioni della tecnologia a banda ultra-larga nell'ambito del posizionamento radio, cosicché dei nodi installati su un braccio automatico riescano a permettere a quest'ultimo di individuare degli oggetti a brevi distanze con la più elevata accuratezza. In prima istanza sono stati analizzati diversi aspetti dei sistemi di posizionamento radio (metodi di localizzazione, tecnologie etc.), poi è stata descritta la tecnologia UWB e, successivamente, sono stati descriti i parametri utilizzati per valutare le prestazioni del sistema (GDOP, PEB, RMSE). Dopo aver effettuato anche un'analisi teorica delle prestazioni, è stato introdotto il sistema di misure utilizzato nell'applicazione ed infine sono stati riportati e analizzati i risultati delle misure ritenuti più rilevanti