R M Tanguay, L Nicole, M Vincent, L Moisan, J Girard
{"title":"[Regulation of genetic expression during the transfer of information from the nucleus to the cytoplasm].","authors":"R M Tanguay, L Nicole, M Vincent, L Moisan, J Girard","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>In eukaryotes, the transfer of genetic information from the genome to its final site of phenotypic expression is a multistep process. These steps are described and the mechanisms of regulation operating at these various levels are reviewed. The heat shock response in two diptera, Drosophila and Chironomus, is described as a model system to illustrate the existence of regulation mechanisms at different levels of genetic information transfer. In Chironomus tentans like in Drosophila, a short heat shock (10 min, 39 degrees C) treatment induces the synthesis of at least 8 new proteins. This is accompanied by a drastic reduction in the synthesis of the normal proteins that in those synthesized prior to the shock. The localisation of these induced proteins has been studied by microdissection of the various intranuclear and intracellular compartments of salivary glands. While most of these have a ubiquitous distribution, one induced protein (34 000 Daltons) is exclusively localized in the nucleus. Another one (25 000 Daltons) is mainly concentrated in a particulate form which cosediments with ribosomes. Arsenite and anaerobiosis do not induce a heat shock mimicking response in Chironomus. The induction mechanisms as well as the transcriptional and translational controls operating during the heat shock response are discussed.</p>","PeriodicalId":21345,"journal":{"name":"Revue canadienne de biologie","volume":"39 1","pages":"9-20"},"PeriodicalIF":0.0,"publicationDate":"1980-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18054723","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":"[Biosynthesis of polypeptide hormones].","authors":"P Crine, N G Seidah, F Gossard, M Lis, M Chrétien","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The biosynthesis of numerous polypeptide hormones implicates two types of precursors: pre- and prohormones. The structure, characteristics, and role of these hormone precursors is discussed taking as examples parathyroid hormone and insulin. After this general introduction, the case of the common precursor for adrenocorticotropin and beta-lipotropin is then discussed. Its maturation proceeds through a serie of proteolytic steps which lead to the formation of various end products characterized each by a biological activity of its own.</p>","PeriodicalId":21345,"journal":{"name":"Revue canadienne de biologie","volume":"39 1","pages":"35-53"},"PeriodicalIF":0.0,"publicationDate":"1980-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17320483","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":"[Synthesis and maturation of RNA after proliferative stimulation: comparison between fibroblasts and lymphocytes].","authors":"J G Kaplan, M Mitchell, E Bard","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Comparison of the regulation of RNA metabolism following stimulation of mammalian fibroblasts in culture and of lymphocytes reveals that in both systems it is the processing and transport of gene transcripts which are the initial targets of the activation process rather than the gene transcription itself. In the case of the human lymphocyte, the time required for appearance of labeled RNA in cytoplasm after addition of labeled uridine diminishes progressively with duration of incubation with mitogen. Using adenine as a marker diminishes the latent period between addition of label and its appearance in cytoplasmic RNA. This may be due to polyadenylation of preexisting transcripts which are turned over at a high rate in the nucleus of resting cells but stabilized, processed and exported to the cytoplasm after stimulation.</p>","PeriodicalId":21345,"journal":{"name":"Revue canadienne de biologie","volume":"39 1","pages":"21-33"},"PeriodicalIF":0.0,"publicationDate":"1980-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17226967","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":"Changes in rat gastric proteases with age: effect of hydrocortisone.","authors":"G Pelletier, J Lanoë, J Dunnigan","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Gel filtration on Sephadex G-75 of rat gastric mucosal preparation shows two peaks of proteolytic activity. These peaks differ at different ages of animals. The proteolytic activity of the gastric mucosa is spread over a wider range of pH in younger animals than older ones with a shift from higher pH towards lower pH values with increasing age. Hydrocortisone injection to nine day-old rats results in qualitative changes of gastric mucosal proteases, the proteolytic activity pattern of young treated animals being similar to that of untreated adult rat.</p>","PeriodicalId":21345,"journal":{"name":"Revue canadienne de biologie","volume":"38 4","pages":"317-9"},"PeriodicalIF":0.0,"publicationDate":"1979-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11267330","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":"Energetic cost of terrestrial locomotion: biped and quadruped runners compared.","authors":"F V Paladino, J R King","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Reanalysis of empirical data relating the energetic ost of running (Erun = cm3 02 g-1 km-1) to body mass (g) indicate the slopes of these regression analyses are indistinguishable when bipeds and quadrupeds are compared. The results agree with previous theoretical conclusions that the cost of transport in all runners scales on body mass (g) raised to the -1/3 power. The comparison also suggests that there is no difference between the energetic cost of maintaining a running posture for bipeds and quadrupeds and this postural cost is much less than original estimates.</p>","PeriodicalId":21345,"journal":{"name":"Revue canadienne de biologie","volume":"38 4","pages":"321-3"},"PeriodicalIF":0.0,"publicationDate":"1979-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11750556","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":"Quality of light effects on immature stages and adults of Pieris rapae (L.) (Lepidoptera: Pieridae).","authors":"D A Thoms, B J Philogène","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Larvae of Pieris rapae (L.), the imported cabbage worm, were reared to the adult stage under controlled light conditions. Spectral quality affected their development. The effect of the long wave ultraviolet light was to significantly decrease developmental time. The light source used also appeared to exert an effect on pupal colouration.</p>","PeriodicalId":21345,"journal":{"name":"Revue canadienne de biologie","volume":"38 3","pages":"157-65"},"PeriodicalIF":0.0,"publicationDate":"1979-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11719445","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}
E D Lalague, A A Abugaber, S J Martin, R E Gaulin, G H Cousineau
{"title":"Preparation of human leukocytes for SEM observation: a modified technique.","authors":"E D Lalague, A A Abugaber, S J Martin, R E Gaulin, G H Cousineau","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Variations in the mode of preparation, type of fixation and leukocyte collection can plan an important part in the determination of the surface structure of a given population, and can result in modifications of the microprojections, and their number, evident on the cell surface. We present preparatory modes that circumvent these difficulties, and the results obtained clearly show that the techniques are profitable, appear essential for the preservation of cell population and integrity, and allow accurate scanning electron microscopy observations without resort to time consuming procedures. Indeed, the entire process can be completed in one day.</p>","PeriodicalId":21345,"journal":{"name":"Revue canadienne de biologie","volume":"38 3","pages":"195-9"},"PeriodicalIF":0.0,"publicationDate":"1979-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11720639","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":"The effects of hypophysectomy on the retinomotor responses of the killifish, Fundulus heteroclitus.","authors":"M A Ali, G E Pickford","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>This paper presents the results of an investigation concerned with the effects of long-term hypophysectomy on the retinomotor responses of the euryhaline killifish, Fundulus heteroclitus: 1. The eye of hypophysectomised Fundulus heteroclitus responds to light and dark in the same manner as that of intact controls: the retina is not in a state of permanent light-adaptation as claimed by Vilter (1942) for the hypophysectomised eel. 2. There is no evidence of a persistent circadian rhythm during continous darkness. 3. Unilateral illumination of the eye of intact fish results in dispersion of retinal pigment in both illuminated and unilluminated eyes, as in the goldfish (Ali, 1964), but no such contralateral response was evident after hypophysectomy. The cones are unresponsive.</p>","PeriodicalId":21345,"journal":{"name":"Revue canadienne de biologie","volume":"38 3","pages":"139-44"},"PeriodicalIF":0.0,"publicationDate":"1979-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11719443","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":"[Elongated mitotic cells in the neuroepithelium of Xenopus laevis and Notophtalmus viridescens].","authors":"C Séguin, P E Messier","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Most neuroepithelial cells in the embryos of Xenopus laevis and Notophtalmus viridescens become round upon entering into mitosis. However, many maintain their elongated form, or show long cytoplasmic processes, during mitosis. It therefore seems possible that, in these species, two groups of microtubules are present during mitosis: cytoplasmic microtubules and mitotic microtubules.</p>","PeriodicalId":21345,"journal":{"name":"Revue canadienne de biologie","volume":"38 3","pages":"173-6"},"PeriodicalIF":0.0,"publicationDate":"1979-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11719447","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":"Visual pigment absorbance and scotopic spectral sensitivity in the goldfish, Carassius auratus.","authors":"J K Bowmaker","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Factors relating to the comparison of the absorbance spectra of visual pigments to experimentally determined relative spectral sensitivities of the eye are discussed with specific reference to the goldfish. It is concluded that the experimentally determined scotopic sensitivity of the goldfish can be directly related to the absorbance of goldfish porphyropsin without the need to infer input from long wavelength-sensitive cones.</p>","PeriodicalId":21345,"journal":{"name":"Revue canadienne de biologie","volume":"38 3","pages":"185-7"},"PeriodicalIF":0.0,"publicationDate":"1979-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11720638","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}