Revue canadienne de biologie最新文献

{"title":"[The role of the corpus callosum and other commissures in the interhemispheric transfer of visual information].","authors":"M Ptito,&nbsp;F Leporé,&nbsp;M Lassonde,&nbsp;D Miceli,&nbsp;J P Guillemot","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>In order to assess the contribution of the lateral suprasylvian area and subcortical pathways other than the corpus callosum in learning and interhemispheric transfer, a series of studies was undertaken in the cat. Groups of animals which received different types of cortical and subcortical lesions were tested for learning and interocular transfer of visual pattern discriminations. Results have shown that : 1. the lateral suprasylvian area is of equal importance in learning and transfer as areas 17, 18 and 19; 2. in the absence of the corpus callosum, other commissures could preserve interocular transfer of visual information. The results obtained on commissurotomized neonate kittens clearly support this assumption.</p>","PeriodicalId":21345,"journal":{"name":"Revue canadienne de biologie","volume":"40 1","pages":"61-8"},"PeriodicalIF":0.0,"publicationDate":"1981-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18259770","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Retinal adaptations to habitat].","authors":"M A Ali","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Vertebrates have, through the process of evolution, adapted to their photic environment. This is well manifested in the retinal adaptations to various habitats. Although all vertebrates are considered, emphasis is placed on fishes because they form about 50% of the vertebrate species. In addition, they occupy a wide range of habitats, thus retinal modifications of fishes serve as models for all other vertebrates. The present article reviews morphological, physiological and biochemical retinal adaptations. The quality and quantity of light reaching the aquatic organism are functions of the incident light as well as the aquatic environment. Thus, in well lit, clear waters fishes are arhythmic and possess almost equal populations of rods and cones; whereas fishes in dimly lit environments (due to turbidity or depth) have retinas that are more specialised for high sensitivity-multi-banked retinas, long outer segments, grouped photoreceptors, hypertrophied ellipsoid mitochondria, reflecting tapetum. Similarly, the ratio and distribution of visual pigments (rhodopsin and porphyropsin) and S-potential change with respect to fresh/sea water, clear/turbid water and air/aquatic environments. Thus, in fresh waters, where the photic environment shifts to longer wavelengths, porphyropsin predominates; while in land vertebrates and almost all marine fishes the dominant pigment is rhodopsin. With respect to the latter, fishes in turbid, greenish or yellowish coastal waters have 'rhodopsins' with lambda mas above 500 nm; fishes in clear coastal habitats have 'rhodopsins' with lambda max near 500 nm; while those in the blue-lit environment of deep seas have lambda max below 500 nm. The retinal pigment composition is also associated with habitat changes during diadromous migrations in fishes or during amphibian metamorphosis. It is interesting to note that the dorsal and ventral retinas of Rana catesbeiana and Anableps microlepis which view aquatic and aerial environments, respectively, show a predominately porphyropsin-rich dorsal retina compared to a rhodopsin-rich ventral retina. Similar shifts in the S-potential are observed with change in habitats. Fresh water fishes exhibit L-responses with lambda max in longer wavelengths compared to marine fishes where the maximum of the L-response shifted towards shorter wavelengths.</p>","PeriodicalId":21345,"journal":{"name":"Revue canadienne de biologie","volume":"40 1","pages":"3-17"},"PeriodicalIF":0.0,"publicationDate":"1981-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18259767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Interhemispheric competition during postnatal development].","authors":"M Cynader,&nbsp;F Leporé,&nbsp;J P Guillemot,&nbsp;M Feran","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The corpus callosum is a bidirectional pathway interconnecting the visual cortices on the two sides of the brain. Rearing kittens with the optic chiasm sectioned and one eyelid sutured during early development results in a functional asymmetry in this pathway. Visual input originating on the side of the brain ipsilateral to the sutured eye looses the ability to influence cells on the other side of the brain. Conversely, visual input originating on the side of the brain ipsilateral to the exposed eye markedly increases its influence in the other hemisphere. These physiologic findings are paralleled by anatomic results indicating that the terminal field of the corpus callosum is markedly expanded in the cortical hemisphere ipsilateral to the deprived eye and reduced in the other hemisphere.</p>","PeriodicalId":21345,"journal":{"name":"Revue canadienne de biologie","volume":"40 1","pages":"47-51"},"PeriodicalIF":0.0,"publicationDate":"1981-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18259768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Role of the contralateral cortex on the receptive field properties in the visual cortex of cats].","authors":"F Leporé,&nbsp;M Ptito,&nbsp;A Samson,&nbsp;J P Guillemot","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The aim of this series of experiments was to evaluate the receptive field properties of visual cells receiving part of their input the corpus callosum. Normal (control) and chiasma sectioned cats were recorded using conventional methods. The recording sites were the 17-18 border and the lateral suprasylvian (LS) cortex. The results indicated (a) the ocular dominance distribution was shifted towards the ipsilateral eye in the split chiasma cats; (b) orientation tunning and/or directional specificity were identical for the two eyes; (c) R.F. positions of binocular cells were also similar for each eye and were clustered near the vertical meridian, which they sometimes straddled; (d) R.F. sizes were larger in L.S. than in primary visual cortex but generally of equal dimensions for each eye. The results are interpreted with respect to the various functions which have been postulated for the corpus callosum.</p>","PeriodicalId":21345,"journal":{"name":"Revue canadienne de biologie","volume":"40 1","pages":"53-60"},"PeriodicalIF":0.0,"publicationDate":"1981-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18259769","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Diurnal changes in the pigeon electroretinogram.","authors":"S Barattini,&nbsp;B Battisti,&nbsp;L Cervetto,&nbsp;P Marroni","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The spectral sensitivity of the pigeon Electroretinogram was determined at different times during the 24-hour cycle. These measures show that diurnal changes occur in the relative sensitivity of the electroretino-graphic responses to light stimuli of different wavelength. Diurnal variations occur despite the absence of rhythmic photoperiodic stimulation. It is suggested that a spontaneous shift occurs in the functional dominance of cones and rods with a period near to 24 hours.</p>","PeriodicalId":21345,"journal":{"name":"Revue canadienne de biologie","volume":"40 1","pages":"133-7"},"PeriodicalIF":0.0,"publicationDate":"1981-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18210871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Ecological niches and morphometric development of visual centers in primates].","authors":"G Baron","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Volumes of the lateral geniculate body and the tractus opticus from 12 species of Prosimians and 10 species of Simians were examined. The progression indices of the lateral geniculate Body do not differ significantly neither between Prosimians and Simians nor between diurnal and nocturnal Primates. Therefore, they cannot be considered as a criterion for phylogenetic development or for eco-ethological adaptations such as activity cycles. The progression indices of the tractus opticus, however, are higher in diurnal than in nocturnal Primates. The two-groups discriminant function based on the progression indices of the lateral geniculate body and the optic tract serves to establish a line which separates nocturnal from diurnal Primates. The lack of any correspondance in the progression of these two brain structures may be explained by the differential development of magnocellular and parvocellular layers of the lateral geniculate body.</p>","PeriodicalId":21345,"journal":{"name":"Revue canadienne de biologie","volume":"40 1","pages":"85-9"},"PeriodicalIF":0.0,"publicationDate":"1981-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18259773","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Two pools of amines in synaptic vesicles of rat pineal nerves.","authors":"A Pellegrino de Iraldi,&nbsp;J P Corazza","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Two pools of amines (noradrenaline and serotonin) are characterized by histochemistry and electrical stimulation in the synaptic vesicles from rat pineal nerves : a loosely bound pool located in the matrix and a tightly bound pool located in the core. A similar distribution is adopted by the false transmitter formed by the administration of 5-hydroxydopamine. The behaviour of both pools under electrical stimulation and in resting conditions is compatible with the idea that the amines stored in the core form a reserve pool and the amines stored in the matrix correspond to a functional pool, which can be released spontaneously and by electrical stimulation, being replaced by the transmitter newly synthesized or by the amines stored in the core. (A presentation of these results was made at the III International Symposium on Nervous Transmission, Helsinki, Finland, 1979).</p>","PeriodicalId":21345,"journal":{"name":"Revue canadienne de biologie","volume":"40 1","pages":"101-9"},"PeriodicalIF":0.0,"publicationDate":"1981-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18256438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"First step in vision: proton transfer or isomerization?","authors":"P Dupuis,&nbsp;F I Hárosi,&nbsp;C Sándorfy,&nbsp;J M Leclercq,&nbsp;D Vocelle","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Recent views on the photochemistry of (vertebrate) vision are examined. Problems related to the structure of the proton bridge at the Schiff base chromophore are considered, in particular the possible shapes of the section of the potential surface governing the motion of the proton in the bridge. This leads to the question as to whether proton translocation occurs in the initial step of visual transduction and if it precedes or follows cis-trans isomerisation. The related controversy could be solved through the assumption of the presence of water molecules that stabilize the ions in the proton bridge. The causes of the instability of bathorhodopsin are discussed and the importance of additional perturbations by polar groups is stressed.</p>","PeriodicalId":21345,"journal":{"name":"Revue canadienne de biologie","volume":"39 4","pages":"247-58"},"PeriodicalIF":0.0,"publicationDate":"1980-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17325505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[Oxidative phosphorylation in Mycobacterium lepraemurium].","authors":"M Ishaque,&nbsp;C Adapoe,&nbsp;L Kato","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The generation of ATP by cell-free extracts of Mycobacterium lepraemurium isolated from Sprague-Dawley rats was investigated. Cell-free preparations catalyzed phosphorylation coupled to the oxidation of NADH and succinate yielding P/O ratios of 0.6 and 0.4, respectively. Ascorbate oxidation did not result in ATP formation. The oxidative phosphorylation was uncoupled by 2,4- dinitrophenol and pentachlorophenol. Phosphate esterification coupled to NADH oxidation was inhibited by rotenone which had no effect on ATP synthesis associated with succinate oxidation. Antimycin A and cyanide completely inhibited phosphorylation coupled to the oxidation of NADH or succinate.</p>","PeriodicalId":21345,"journal":{"name":"Revue canadienne de biologie","volume":"39 4","pages":"219-23"},"PeriodicalIF":0.0,"publicationDate":"1980-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18062852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Interference of Neisseria gonorrhoeae growth by aerobic bacterial representatives of the urogenital flora.","authors":"J G Bisaillon,&nbsp;R Beaudet,&nbsp;S A Saheb,&nbsp;R Morisset","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Aerobic bacterial isolates obtained from endocervical, vaginal and urethral swabbings were tested for interference of neisseria gonorrhoeae growth on solid medium. Simultaneous antagonism was studied using the lawn spotting method, and delayed antagonism by the basal spot/lawn method. From 58 swabbings we recuperated a total of 181 isolates, 71 of those were found interfering with at least one out of four gonococcal strains (G-1, G-2, G-3 and G-4). Similar percentages of interfering isolates were obtained from each of the isolation sites. The identification of the interfering isolates has revealed that similar numbers of coagulase negative staphylococci and identical numbers of group D streptococci were found for each of those sites. The majority of the interfering isolates and also of the inhibitory coagulase negative staphylococci showed only simultaneous antagonism. To complete the interference spectrum, we have tested all the active urogenital isolates against four other gonococcal strains (G-7, G-9, G-10 and G-11). This spectrum showed clearly that interference is not an all or none phenomenon. While the gonococcal interference spectrum of most of the Gram positive cocci and the Acinetobacter sp. strains is broad, that of all the other isolates is relatively narrow. Gonococcal strains G-7 and G-9 were the most susceptible to inhibition by the interfering urogenital isolates while strain G-3 was the most resistant one.</p>","PeriodicalId":21345,"journal":{"name":"Revue canadienne de biologie","volume":"39 4","pages":"201-8"},"PeriodicalIF":0.0,"publicationDate":"1980-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17838151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}