Search

A typographical error appeared in the author’s name of the article entitled “Inhibitory Effect of Codeine on Sucrase Activity“ by Dariush Minai-Tehrani, Saeed Minoui, Marzie Sepehre, Zohre Sharif-Khodai, Tooka Aavani, Drug Metabolism Letters, 2009; 3(1): 58-60. [1]. Details of the error and a correction are provided here. The fourth author#039;s name in this article was misspelled. Hence it should be read as "Zohreh Sharifkhodaei" as per the request of the author. We regret the error and apologize to readers. The original article can be found online at: https://www.eurekaselect.com/93132/article Original: Zohre Sharif-Khodai Corrected: Zohreh Sharifkhodaei

Rod and cone photoreceptors are photosensitive cells in the retina that convert light to electrical signals that are transmitted to visual processing centres in the brain. During development, cones and rods are generated from a common pool of multipotent retinal progenitor cells (RPCs) that also give rise to other retinal cell types. Cones and rods differentiate in two distinct waves, peaking in mid-embryogenesis and the early postnatal period, respectively. As RPCs transition from making cones to generating rods, there are changes in the expression profiles of genes involved in photoreceptor cell fate specification and differentiation. To better understand the temporal transition from cone to rod genesis, we assessed the timing of onset and offset of expression of a panel of 11 transcription factors and 7 non-transcription factors known to function in photoreceptor development, examining their expression between embryonic day (E) 12.5 and postnatal day (P) 60. Transcription factor expression in the photoreceptor layer was observed as early as E12.5, beginning with Crx, Otx2, Rorb, Neurod1 and Prdm1 expression, followed at E15.5 with the expression of Thrb, Neurog1, Sall3 and Rxrg expression, and at P0 by Nrl and Nr2e3 expression. Of the non-transcription factors, peanut agglutinin lectin staining and cone arrestin protein were observed as early as E15.5 in the developing outer nuclear layer, while transcripts for the cone opsins Opn1mw and Opn1sw and Recoverin protein were detected in photoreceptors by P0. In contrast, Opn1mw and Opn1sw protein were not observed in cones until P7, when rod-specific Gnat1 transcripts and rhodopsin protein were also detected. We have thus identified four transitory stages during murine retina photoreceptor differentiation marked by the period of onset of expression of new photoreceptor lineage genes. By characterizing these stages, we have clarified the dynamic nature of gene expression during the period when photoreceptor identities are progressively acquired during development.

We report successful retinal cone enrichment and transplantation using a novel cone-GFP reporter mouse line. Using the putative cone photoreceptor-enriched transcript Coiled-Coil Domain Containing 136 (Ccdc136) GFP-trapped allele, we monitored developmental reporter expression, facilitated the enrichment of cones, and evaluated transplanted GFP-labeled cones in wildtype and retinal degeneration mutant retinas. GFP reporter and endogenous Ccdc136 transcripts exhibit overlapping temporal and spatial expression patterns, both initiated in cone precursors of the embryonic retina and persisting to the adult stage in S and S/M opsin(+) cones as well as rod bipolar cells. The trapped allele does not affect cone function or survival in the adult mutant retina. When comparing the integration of GFP(+) embryonic cones and postnatal Nrl(-/-) 'cods' into retinas of adult wildtype and blind mice, both cell types integrated and exhibited a degree of morphological maturation that was dependent on donor age. These results demonstrate the amenability of the adult retina to cone transplantation using a novel transgenic resource that can advance therapeutic cone transplantation in models of age-related macular degeneration.

We report successful retinal cone enrichment and transplantation using a novel cone-GFP reporter mouse line. Using the putative cone photoreceptor-enriched transcript Coiled-Coil Domain Containing 136 (Ccdc136) GFP-trapped allele, we monitored developmental reporter expression, facilitated the enrichment of cones, and evaluated transplanted GFP-labeled cones in wildtype and retinal degeneration mutant retinas. GFP reporter and endogenous Ccdc136 transcripts exhibit overlapping temporal and spatial expression patterns, both initiated in cone precursors of the embryonic retina and persisting to the adult stage in S and S/M opsin+ cones as well as rod bipolar cells. The trapped allele does not affect cone function or survival in the adult mutant retina. When comparing the integration of GFP+ embryonic cones and postnatal Nrl−/− ‘cods’ into retinas of adult wildtype and blind mice, both cell types integrated and exhibited a degree of morphological maturation that was dependent on donor age. These results demonstrate the amenability of the adult retina to cone transplantation using a novel transgenic resource that can advance therapeutic cone transplantation in models of age-related macular degeneration.

Despite the apparent uniformity in cellular composition of the adult mammalian cerebellar cortex, it is actually highly compartmentalized into transverse zones and within each zone further subdivided into a reproducible array of parasagittal stripes. This basic cerebellar architecture is highly conserved in birds and mammals. However, different species have very different cerebellar morphologies, and it is unclear if cerebellar architecture reflects taxonomic relations or ecological niches. To explore this, we have examined the cerebellum of the naked mole-rat Heterocephalus glaber, a burrowing rodent with adaptations to a subterranean life that include only a rudimentary visual system. The cerebellum of H. glaber resembles that of other rodents with the remarkable exception that cerebellar regions that are prominent in the handling of visual information (the central zone, nodular zone, and dorsal paraflocculus) are greatly reduced or absent. In addition, there is a notable increase in size in the posterior zone, consistent with an expanded role for the trigeminal somatosensory system. These data suggest that cerebellar architecture may be substantially modified to serve a particular ecological niche.

Scopolamine (hyoscine) is commonly used as an anticholinergic drug to relieve nausea, vomiting and dizziness of a motion sickness as well as recovery from anesthesia and surgery. Sucrase as a hydrolytic enzyme breaks down sucrose into its monomers, glucose and fructose. The aim of this study was to evaluate the effect of scopolamine on the activity and the structural changes of yeast sucrase. The results showed that binding of scopolamine to sucrase could inhibit the enzyme activity. A non-competitive inhibition was observed in different concentrations of scopolamine (0.6 to 3.6mM). The study by circular dichroism measurement in far-UV showed that the absolute enzyme exhibited a flat negative trough, indicating the presence of alpha-helices and beta-sheet structures in the enzyme. Binding of the inhibitor on the enzyme made a deeper trough at 218nm, suggesting the increasing of beta-sheet content of the enzyme. Fluorescence measurement showed that binding of scopolamine to free enzyme and enzyme-substrate complex increased the peak intensity at 350nm and also induced red shift. Our findings suggest that scopolamine binds to the location other than the active site of enzyme and that the binding causes structural changes and inhibits the enzyme activity.

The locus coeruleus (LC) located at the level of the pons, is involved in cognitive functions such as learning and memory. The bilateral lidocaineinduced reversible inactivation of this nucleus has been considered in order to study its role in the phases of memory processing (acquisition, consolidation and retention) without any interference with the function of the same structure either during earlier and/or later phases of the same process. In this study, inhibitory avoidance (IA) learning task used to find the LC function in acquisition, consolidation and retrieval. Saline or lidocaine 4% (0.5l/side) microinjected into the LC, for assessing the acquisition (5 min before training), consolidation (5, 90 and 360 min after training) and memory retrieval, 5 min before testing. The retention test was done 24 h after learning. Our results indicated that: (1) The bilateral functional inactivation of LC before training did not affect acquisition, but affected subsequent memory retention 24 h later in IA task. (2) The lidocaine-induced inactivation of LC only 5 min after training impaired consolidation but did not affect it after 90 or 360 min. (3) Inactivation of the LC, 5 min before pre-retrieval test, impaired memory retrieval in IA task. In conclusion, it seems that the nucleus locus coeruleus does not affect acquisition while it involves in the memory consolidation and retrieval of inhibitory avoidance learning task. Published by Elsevier B.V.

Codeine is a common drug widely used in some countries as a pain reliever. The effect of codeine on yeast sucrase activity was studied in this report. Non-competitive inhibition was observed using double reciprocal plot. The Km of enzyme did not change in the presence of different concentrations of codeine (0.5- 1.5 mM) and was determined about 11.5 mM. The Vmax of enzyme was determined about 8.8 mM/min, and the Vmax decreased in the presence of codeine. The Ki of codeine was measured by using the reaction rate and the initial concentration of the inhibitor according to the Dixon plot. The Ki was found to be 0.42 mM and the IC50 of codeine was determined about 0.875 mM.