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Revue canadienne de biologie最新文献

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Streptococcus mutans, an assessment of its physiological potential in relation to dental caries. 变形链球菌，对其与龋齿相关的生理潜能的评估。
Revue canadienne de biologie Pub Date : 1978-12-01
J D Ruby, M Goldner, J A Hargreaves
{"title":"Streptococcus mutans, an assessment of its physiological potential in relation to dental caries.","authors":"J D Ruby,&nbsp;M Goldner,&nbsp;J A Hargreaves","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Streptococcus mutans converts low levels of sucrose to lactic acid, but at high levels favours synthesis of glucans for plaque accumulation. Thus, the continued exposure to sucrose fluxes would select microorganisms in the oral cavity (S. mutans being a prototype) with highly specialized adaptation and potential dental caries activity. The bacteria that have evolved physiological systems to function efficiently under these conditions are the lactic acid bacteria. These organisms survive in environments where carbohydrate availability is constantly changing. High tolerances to acidic environments may be an important determinant in establishing the ecology of the carious lesion. Also, the intercellular polysaccharide storgae (glycogenamylopectin) and extracellular polymer reserves (levan and soluble glucan) are important during carbohydrate depletion. Further, the formation of insoluble glucans is a prerequisite for the caries process on smooth surfaces of teeth through plaque development. These conditions could result in an increase in S. mutans and cariogenic microorganisms. As a result, this process may be best understood as a manifestation of an amphibiotic shift.</p>","PeriodicalId":21345,"journal":{"name":"Revue canadienne de biologie","volume":"37 4","pages":"273-89"},"PeriodicalIF":0.0,"publicationDate":"1978-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11254878","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}
引用次数: 0
[Cytospectrophotometry of hepatocyte RNA in regenerating and neoplastic liver]. [再生肝和肿瘤肝细胞RNA的细胞分光光度法]。
Revue canadienne de biologie Pub Date : 1978-12-01
M C Moulin-Camus, R Daoust
{"title":"[Cytospectrophotometry of hepatocyte RNA in regenerating and neoplastic liver].","authors":"M C Moulin-Camus,&nbsp;R Daoust","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The present work consists in a quantitative cytospectrophotometric investigation of the cytoplasmic hyperbasophilia that characterizes the foci of neoplastic transformation and the tumor cells in rats fed hepatocarcinogens. It reveals that the increase in the dye-binding capacity shown by the cytoplasmic RNA of these cell populations results primarily form a qualitative alteration which raises the affinity for basic dyes by a factor of nearly 2, and also to a change in concentration due to volumetric changes which may again double the staining intensity of these hepatocytes. This phenomenon of hyperbasophilia differs radically from the weak variations in basophilia observed in normal regenerating liver and in hyperplastic liver parenchyma of rats fed the carcinogenic diet in which cases the changes appear to be related mainly to de nova RNA synthesis. Biochemical assays on cellular fractions indicate that the ribosomes are the organelles responsible for the hyperbasophilic properties that hepatocytes acquire in areas of neoplastic transformation.</p>","PeriodicalId":21345,"journal":{"name":"Revue canadienne de biologie","volume":"37 4","pages":"235-55"},"PeriodicalIF":0.0,"publicationDate":"1978-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11304759","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}
引用次数: 0
Photochemistry of visual pigments: an interpretation of spectral changes in terms of molecular associations and isomerization. 视觉色素的光化学:从分子结合和异构化角度解释光谱变化。
Revue canadienne de biologie Pub Date : 1978-12-01
F I Hárosi, J Favrot, J M Leclercq, D Vocelle, C Sándorfy
{"title":"Photochemistry of visual pigments: an interpretation of spectral changes in terms of molecular associations and isomerization.","authors":"F I Hárosi,&nbsp;J Favrot,&nbsp;J M Leclercq,&nbsp;D Vocelle,&nbsp;C Sándorfy","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>A unified view of the photochemical part of the visual process is presented. It is proposed that both conformational changes and changes in intermolecular interactions in the sequence that leads from rhodopsin through batho-lumi- and meta-I to meta-II- rhodopsin have to be considered in order to elucidate the mechanism of the visual process. The main intermolocular associations are assumed to be the hydrogen bond involving the nitrogen atom of the Schiff base and the interaction between a negative group and the beta-ionone ring. The two together can be used to explain the absorption wavelength of rhodopsin without actual protonation. The main line of thought is as follows: when light is absorbed the basicity of the Schiff base increases significantly. This triggers proton transfer in the H-bond. At the same time cis-trans isomerization begins but it only reaches the coplanar all-trans stage at metarhodopsin-II. Lumi-, meta-I and meta-II are way stations in the stepwise isomerization whereby the energy of the photon is used together with thermal energy. Batho- is probably still close to 11-cis which then becomes successively strained 13-cis and 15-cis. In vertebrate rhodopsins at the meta-II stage both the H-bond and the beta-ionone interaction are severed and meta-II becomes exposed to attack by water molecules. The importance of syn-anti isomerization on the C=N bond is emphasized. The irreversibility necessary for the production of a signal requires that the proton does not return to its original donor. The possible identity of the donor is discussed: it might be an amino acid or the polar part of a lipid. Relevant observations made on bacteriorhodopsin, squid rhodopsin and chicken iodopsin are discussed.</p>","PeriodicalId":21345,"journal":{"name":"Revue canadienne de biologie","volume":"37 4","pages":"257-71"},"PeriodicalIF":0.0,"publicationDate":"1978-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11933970","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}
引用次数: 0
Optical characteristics of the eye of the spiny dogfish (Squalus acanthias). 刺角鲨(角鲨)眼睛的光学特性。
Revue canadienne de biologie Pub Date : 1978-09-01
J G Sivak
{"title":"Optical characteristics of the eye of the spiny dogfish (Squalus acanthias).","authors":"J G Sivak","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>On the basis of the failure of attempts to induce refractive accommodation changes electrically and with drugs, it appears that the eye of the spiny dogfish (Squalus acanthias) lacks the capacity to accommodate. Retinoscopic measurements indicate moderate hyperopia (+6D). However, measurements made with light restricted to the short end of the visible spectrum indicate only one or two dioptres of hyperopia and it is possible that the latter measurements are more coincident with natural conditions. In contrast to the somewhat flattened lens of other elasmobranchs the lens of the spiny dogfish is nearly spherical. The fact that its refractive index is high (1.66) suggests that the static optical system of this eye is very similar to that of the teleosts.</p>","PeriodicalId":21345,"journal":{"name":"Revue canadienne de biologie","volume":"37 3","pages":"209-17"},"PeriodicalIF":0.0,"publicationDate":"1978-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11915908","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}
引用次数: 0
[Uptake of polyribonucleotidies by isolated rat liver mitochondria]. [离体大鼠肝脏线粒体对多核糖核苷酸的摄取]。
Revue canadienne de biologie Pub Date : 1978-09-01
L Giguère, R Morais
{"title":"[Uptake of polyribonucleotidies by isolated rat liver mitochondria].","authors":"L Giguère,&nbsp;R Morais","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":21345,"journal":{"name":"Revue canadienne de biologie","volume":"37 3","pages":"189-200"},"PeriodicalIF":0.0,"publicationDate":"1978-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11254222","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}
引用次数: 0
Microspectrophotometric studies on the visual pigment in the intact retina of the goldfish, Carassius auratus (Linn.). 金鱼(Carassius auratus, Linn.)完整视网膜中视色素的显微分光光度研究。
Revue canadienne de biologie Pub Date : 1978-09-01
E S Zyznar, W L Larson, M A Ali
{"title":"Microspectrophotometric studies on the visual pigment in the intact retina of the goldfish, Carassius auratus (Linn.).","authors":"E S Zyznar,&nbsp;W L Larson,&nbsp;M A Ali","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The visual pigments in intact retinas of the common goldfish were examined by microspectrophotometry. Difference spectra free of photoproduct contamination had absorbance maxima at lambda527 nm +/- 2 nm. The average pigment density, about 0.32, was almost invariant with regard to retinal location and specimen size. Traces of a photoproduct absorbing maximally at lambda480-490 nm were found. The normalized \"absorbance\" curve deviated from standard templates. It was suggested that this was an effect of cross-coupling of energy and among photoreceptors. Finally, known action spectra show a red shift relative to the absorbance spectra measured.</p>","PeriodicalId":21345,"journal":{"name":"Revue canadienne de biologie","volume":"37 3","pages":"143-56"},"PeriodicalIF":0.0,"publicationDate":"1978-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11915905","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}
引用次数: 0
[Histological and morphometric study of the development of the optic part of the compound eye of the Enallagma boreale Selys (Odonata: Coenagrionidae)]. [对青花蛱蝶复眼光学部分发育的组织学和形态计量学研究]。
Revue canadienne de biologie Pub Date : 1978-09-01
J Lavoie, J G Pilon
{"title":"[Histological and morphometric study of the development of the optic part of the compound eye of the Enallagma boreale Selys (Odonata: Coenagrionidae)].","authors":"J Lavoie,&nbsp;J G Pilon","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The morphology of the optical part of the Enallagma boreale Selys compound eye remains unchanged during its post-embryonic development. The cornea, composed of the epi-, exo- and endocorne, is in perfect continuity with the larval cephalic cuticle. Consequently these two structures possess the same three layers and have a similar process formation. But, the measurements from cephalic endocuticle and endocornea of the adult differ significantly from each other. The latter has a lamellar aspect. The nuclei cornea reaches its morphometric characteristics as early as the pre-emergence stage. The nuclei of the two primary pigment cells which have maintained their epidermic nature, are located at each side of the apex of the crystalline cone. The nuclei of the secondary pigment cells are uniformly distributed in the optical and photosensitive parts. The larval and adult crystalline cones differ morphometrically. The larval one is longer and narrower and reaches its adult characteristics just before emergence. Statistical tests do not show any significant difference between the dorsal and the ventral parts of the larval and adult compound eye.</p>","PeriodicalId":21345,"journal":{"name":"Revue canadienne de biologie","volume":"37 3","pages":"157-80"},"PeriodicalIF":0.0,"publicationDate":"1978-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11915906","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}
引用次数: 0
[Technics of measuring the motive force of very small ameboid cells]. [测量非常小的变形虫细胞动力的技术]。
Revue canadienne de biologie Pub Date : 1978-09-01
C R Gicquaud
{"title":"[Technics of measuring the motive force of very small ameboid cells].","authors":"C R Gicquaud","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>A technic have been perfected which measures directly the motive force of very small ameboid cells and indicates the tropism of the amoeba. By using this technic, the motive force of Entamoeba histolytica was measured. It varied between +/- 1.5 x 10-4 dyne. We have also shown chimiotactism in Entamoeba histolytica. The metabolic coumpound excreted by this cell induced negative tropism.</p>","PeriodicalId":21345,"journal":{"name":"Revue canadienne de biologie","volume":"37 3","pages":"201-8"},"PeriodicalIF":0.0,"publicationDate":"1978-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11429173","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}
引用次数: 0
On possible involvement of adrenocorticoids in chicken spleen development. 肾上腺皮质激素可能参与鸡脾脏发育。
Revue canadienne de biologie Pub Date : 1978-09-01
T W Betz, P Nagler
{"title":"On possible involvement of adrenocorticoids in chicken spleen development.","authors":"T W Betz,&nbsp;P Nagler","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The possible effects of glucocorticoids on spleen development were assessed by the determination of changes in mean organ weight and histology in chicken (Gallus gallus) embryos at stages 44 and 45 of Hamburger and Hamilton on days 19.5 and 20 of incubation (N = 10--13). After the administration of 1 to 6 mg of metopirone (an 11-beta-hydroxylase inhibitor) the numbers of white-pulp periarterial nests and red-pulp granulocytes decreased. The changes associated with metopirone treatment were less evident after the addition of corticosterone (20 and 200 microgram). After adding corticosterone alone (200 microgram), the white-pulp nests appeared larger than in control. Mean body and spleen weights or spleen-body weight ratios did not change much after treatment. Possibly glucocorticoids normally direct these aspects of spleen histogenesis in chicken embryos.</p>","PeriodicalId":21345,"journal":{"name":"Revue canadienne de biologie","volume":"37 3","pages":"181-8"},"PeriodicalIF":0.0,"publicationDate":"1978-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11915907","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}
引用次数: 0
Uptake of lysolecithin and other lysins by rat erythrocytes. 大鼠红细胞对溶卵磷脂和其它溶卵磷脂的摄取。
Revue canadienne de biologie Pub Date : 1978-09-01
K S Cho, P Proulx
{"title":"Uptake of lysolecithin and other lysins by rat erythrocytes.","authors":"K S Cho,&nbsp;P Proulx","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Lysis of rat erythrocytes by lysolecithin, palmitoyl carnitine and palmitoyl choline is inhibited by albumin and by certain lipids. Albumin rapidly forms a complex with the lysins thereby decreasing their reactivity with erythrocytes. Lecithin and cholesterol are lysis inhibitors that do not prevent the uptake of lysins but decrease their interactions with structural elements of the red cell membrane.</p>","PeriodicalId":21345,"journal":{"name":"Revue canadienne de biologie","volume":"37 3","pages":"219-24"},"PeriodicalIF":0.0,"publicationDate":"1978-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11915909","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}
引用次数: 0
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