Search results for "ACID"
showing 10 items of 13107 documents
Interaction of glutamic-acid-rich proteins with the cGMP signalling pathway in rod photoreceptors.
1999
The assembly of signalling molecules into macromolecular complexes (transducisomes) provides specificity, sensitivity and speed in intracellular signalling pathways. Rod photoreceptors in the eye contain an unusual set of glutamic-acid-rich proteins (GARPs) of unknown function. GARPs exist as two soluble forms, GARP1 and GARP2, and as a large cytoplasmic domain (GARP' part) of the beta-subunit of the cyclic GMP-gated channel. Here we identify GARPs as multivalent proteins that interact with the key players of cGMP signalling, phosphodiesterase and guanylate cyclase, and with a retina-specific ATP-binding cassette transporter (ABCR), through four, short, repetitive sequences. In electron mic…
Temporal resolution and temporal transfer properties: gabaergic and cholinergic mechanisms.
2007
Temporal resolution is a basic property of the visual system and critically depends upon retinal temporal coding properties which are also of importance for directional coding. Whether the temporal coding properties for directional coding derive form inherent properties or critically depend upon the temporal coding mechanisms is unclear. Here, the influence of acetylcholine and GABA upon photopic temporal coding was investigated in goldfish, using flicker stimuli, in a behavioral and an electrophysiological (ERG) approach. The goldfish temporal resolution ability decreased from more than 90% correct choices at 20 Hz flicker frequency to about 65% at 45 Hz flicker frequency with a flicker fu…
Polyamines and ripening of photoreceptor outer segments in chicken embryos.
1995
Abstract Polyamines and their related monoacetyl derivatives were studied in rod outer segment (ROS) and cone outer segment (COS) of photoreceptor cells from chick embryo retina during eye development (7th–18th days). Putrescine was found to be necessary, in the second phase of retinogenesis, to sustain both ROS and COS differentiation and, after acetylation, γ-aminobutyric acid synthesis. On the other hand, spermidine and even more spermine intervene in the third phase of development when photoreceptors mature. Moreover, the presence of N1-acetylspermidine already at the 7th day indicates that in the outer segment of photoreceptor cells too, as in the whole retina, putrescine synthesis com…
Multisensory perception of dietary faty-acids in Drosophila.
2012
International audience; Fatty-acids (FAs) are crucial for animal survival and reproduction. However, our knowledge of the mechanisms underlying the perception and preference of dietary FA is limited, particularly in invertebrates. We obtained behavioral data with wild-type Drosophila melanogaster larvae and adults showing a clear preference to some of the FAs tested (C14:0, C16:0, C18:0, C18:1, C18:2, C18:3). These data, based on tests involving both individuals and groups, showed that larvae prefer desaturated FAs whereas adults prefer saturated FAs. Moreover, we found that larval and adult responses relied on olfaction and taste modalities, and maybe also on mechanoperception [1]. We will…
24S-hydroxycholesterol and cholesterol-24S-hydroxylase (CYP46A1) in the retina: from cholesterol homeostasis to pathophysiology of glaucoma.
2011
http://www.sciencedirect.com/; International audience; Free cholesterol is the predominant form of cholesterol in the neural retina. The vertebrate neural retina exhibits its own capacity to synthesize cholesterol and meets its demand also by taking it from the circulation. Defects in cholesterol synthesis and trafficking in the neural retina has detrimental consequences on its structure and function, highlighting the crucial importance of maintaining cholesterol homeostasis in the retina. Our purpose was to give a review on the functioning of the retina, the role of cholesterol and cholesterol metabolism therein, with special emphasis on cholesterol-24S-hydroxylase (CYP46A1). Similar to th…
In vivo consequences of cholesterol-24s-hydroxylase (CYP46A1) inhibition by voriconazole on cholesterol homeostasis and function in the rat retina
2011
Cholesterol 24S-hydroxylase (CYP46A1) converts cholesterol into 24S-hydroxycholesterol in neurons and participates in cholesterol homeostasis in the central nervous system, including the retina. We aimed to evaluate the consequences of CYP46A1 inhibition by voriconazole on cholesterol homeostasis and function in the retina. Rats received daily intraperitoneal injections of voriconazole (60mg/kg), minocycline (22mg/kg), voriconazole plus minocycline, or vehicle during five consecutive days. The rats were submitted to electroretinography to monitor retinal functionality. Cholesterol and 24S-hydroxycholesterol were measured in plasma, brain and retina by gas chromatography-mass spectrometry. T…
The mechanisms of the action of omega-3s in the retina
2013
Age-related Macular Degeneration (AMD) is the leading cause of visual loss in Western countries after the age of 50y. Based on large-scale epidemiologic studies, it appears now as evident that omega-3 polyunsaturated fatty acids (PUFAs) provide benefits in preventing both, early and late stages of AMD. The aim of this paper is to summarize the knowledge about the biological mechanisms by which omega-3 PUFAs may be protective for the retina. The content of this presentation will range from biochemical data about the occurrence of omega-3 PUFAs in retinal cell membranes to results from cellular and animal studies showing that omega-3 PUFAs can influence processes involved in signal transducti…
In vitro evolution of an atrazine-degrading population under cyanuric acid selection pressure: Evidence for the selective loss of a 47kb region on th…
2011
International audience; The adaptation of microorganisms to pesticide biodegradation relies on the recruitment of catabolic genes by horizontal gene transfer and homologous recombination mediated by insertion sequences (IS). This environment-friendly function is maintained in the degrading population but it has a cost which could diminish its fitness. The loss of genes in the course of evolution being a major mechanism of ecological specialization, we mimicked evolution in vitro by sub-culturing the atrazine-degrading Pseudomonas sp. ADP in a liquid medium containing cyanuric acid as the sole source of nitrogen. After 120 generations, a new population evolved, which replaced the original on…
The influence of backslopping on lactic acid bacteria diversity in tarhana fermentation
2020
Tarhana is produced at batch systems in which the microbiota has changed accordingly to the microbial load from ingredients. In order to stabilize the microbiota, the effects of backslopping carried out under different temperature regimes (25 and 30 °C), pH (3.70 and 4.00) and inoculation rates (5, 10 and 15%) on lactic acid bacteria (LAB) diversity were determined in tarhana dough. LAB and Total Aerobic Mesophilic Bacteria (TAMB) numbers increased in all tarhana dough samples subjected to backslopping. Temperature and pH significantly affected the microbiological diversity of tarhana whereas the different inoculation rates did not. Tarhana dough showed complex tarhana microbiota following …
The Forebrain of the Blind Cave Fish <i>Astyanax hubbsi </i>(Characidae)
1997
This paper presents a survey of the cell groups in the telencephalon of the teleost Astyanax hubbsi, based on series of transverse sections stained with the Nissl-, Kluver-Barrera and Bodian procedure