In the silkworm, as is the case in most other insects, trehalose is the principal circulating form of the saccharidic cellular food. The hemolymph contains an enzyme, trehalase, which is normally inhibited. The inhibition is only suppressed during the periods of molting, causing a decrease of the trehalose concentration and an increase of the amount of free glucose. The muscles and most other tissues, such as the digestive tract, are able to use blood trehalose, thanks to an intracellular trehalase. The epidermis and the silk-glands are devoid of trehalase : they use the free glucose liberated by the hydrolysis of the hemolymph trehalose during the periods of molting and spinning. The problem of the origin of the trehalose is discussed, in the light of recent experiments, in which the incorporation of radioactivity from labelled pyruvate and glucose-1-phosphate into fat-body glycogen and hemolymph trehalose has been followed. The chitin of the cuticle is synthesized at every molting process, partly at the expense of the glucose liberated by the hydrolysis of the trehalose in the hemolymph. On the other hand, the old cuticle is destroyed by the proteolytic and chitinolytic enzymes of the exuvial fluid. The hydrolytic products, especially N-acetylglucosamine, are resorbed by the epidermis and can be used for the biosynthesis of the chitin of the new cuticle.
{"title":"Métabolisme du tréhalose et du glycogène chez le Ver à soie, en relation avec la mue, le filage et les métamorphoses","authors":"M. Florkin, C. Jeuniaux","doi":"10.3406/barb.1965.65241","DOIUrl":"https://doi.org/10.3406/barb.1965.65241","url":null,"abstract":"In the silkworm, as is the case in most other insects, trehalose is the principal circulating form of the saccharidic cellular food. The hemolymph contains an enzyme, trehalase, which is normally inhibited. The inhibition is only suppressed during the periods of molting, causing a decrease of the trehalose concentration and an increase of the amount of free glucose. The muscles and most other tissues, such as the digestive tract, are able to use blood trehalose, thanks to an intracellular trehalase. The epidermis and the silk-glands are devoid of trehalase : they use the free glucose liberated by the hydrolysis of the hemolymph trehalose during the periods of molting and spinning. The problem of the origin of the trehalose is discussed, in the light of recent experiments, in which the incorporation of radioactivity from labelled pyruvate and glucose-1-phosphate into fat-body glycogen and hemolymph trehalose has been followed. The chitin of the cuticle is synthesized at every molting process, partly at the expense of the glucose liberated by the hydrolysis of the trehalose in the hemolymph. On the other hand, the old cuticle is destroyed by the proteolytic and chitinolytic enzymes of the exuvial fluid. The hydrolytic products, especially N-acetylglucosamine, are resorbed by the epidermis and can be used for the biosynthesis of the chitin of the new cuticle.","PeriodicalId":296277,"journal":{"name":"Bulletin de la Classe des sciences","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1965-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114608221","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":"A propos de Guillaume Postel","authors":"J. Cox","doi":"10.3406/barb.1964.70819","DOIUrl":"https://doi.org/10.3406/barb.1964.70819","url":null,"abstract":"","PeriodicalId":296277,"journal":{"name":"Bulletin de la Classe des sciences","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1964-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134399685","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":"Astronomie et composition du globe","authors":"J. Cox","doi":"10.3406/barb.1964.65038","DOIUrl":"https://doi.org/10.3406/barb.1964.65038","url":null,"abstract":"","PeriodicalId":296277,"journal":{"name":"Bulletin de la Classe des sciences","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1964-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129172549","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":"La plastification de l'acier doux en flexion plane simple et composée et ses effets sur le flambage par compression des pièces droites élastoplastiques","authors":"F. Campus","doi":"10.3406/barb.1963.65753","DOIUrl":"https://doi.org/10.3406/barb.1963.65753","url":null,"abstract":"","PeriodicalId":296277,"journal":{"name":"Bulletin de la Classe des sciences","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1963-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127908672","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":"I. Plastification de l'acier doux en flexion plane simple","authors":"F. Campus","doi":"10.3406/barb.1963.65726","DOIUrl":"https://doi.org/10.3406/barb.1963.65726","url":null,"abstract":"","PeriodicalId":296277,"journal":{"name":"Bulletin de la Classe des sciences","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1963-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116695444","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":"III. Théorie du flambage par compression des pièces droites élasto-plastiques à plan moyen","authors":"F. Campus","doi":"10.3406/barb.1963.65730","DOIUrl":"https://doi.org/10.3406/barb.1963.65730","url":null,"abstract":"","PeriodicalId":296277,"journal":{"name":"Bulletin de la Classe des sciences","volume":"66 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1963-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126119109","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}
1. L'essentiel de nos connaissances biochimiques sur les hybrides létaux entre Batraciens est présenté dans l'introduction de la présente note. 2. Des expériences nouvelles sont décrites : elles montrent qu'il est possible de modifier dans une large mesure, la proportion relative du DNA et du RNA dans les divers noyaux de l'hybride létal en traitant l'embryon par divers substrats du cycle tricarboxylique et par de l'ATP. En particulier, l'oxaloacétate et le citrate inhibent la synthèse du RNA nucléaire, tandis que le succinate et surtout l'ATP l'augmentent. D'autre part, nous avons pu montrer que, chez l'hybride létal l'utilisation de l'uridine pour la synthèse du RNA et, surtout, pour celle du DNA est fortement réduite. Le RNA synthétisé dans ces conditions se caractérise par une solubilité anormale. 3. Des hypothèses, basées sur des considérations d'ordre biochimique et sur nos connaissances actuelles au sujet du transfert de l'information génétique, sont présentées afin de rendre compte des résultats obtenus et, de manière plus générale, des causes de la létalité.
{"title":"Nouvelles observations et hypothèses sur la létalité chez les hybrides","authors":"J. Brachet","doi":"10.3406/barb.1962.65446","DOIUrl":"https://doi.org/10.3406/barb.1962.65446","url":null,"abstract":"1. L'essentiel de nos connaissances biochimiques sur les hybrides létaux entre Batraciens est présenté dans l'introduction de la présente note. \u0000 2. Des expériences nouvelles sont décrites : elles montrent qu'il est possible de modifier dans une large mesure, la proportion relative du DNA et du RNA dans les divers noyaux de l'hybride létal en traitant l'embryon par divers substrats du cycle tricarboxylique et par de l'ATP. En particulier, l'oxaloacétate et le citrate inhibent la synthèse du RNA nucléaire, tandis que le succinate et surtout l'ATP l'augmentent. \u0000 D'autre part, nous avons pu montrer que, chez l'hybride létal l'utilisation de l'uridine pour la synthèse du RNA et, surtout, pour celle du DNA est fortement réduite. Le RNA synthétisé dans ces conditions se caractérise par une solubilité anormale. \u0000 3. Des hypothèses, basées sur des considérations d'ordre biochimique et sur nos connaissances actuelles au sujet du transfert de l'information génétique, sont présentées afin de rendre compte des résultats obtenus et, de manière plus générale, des causes de la létalité.","PeriodicalId":296277,"journal":{"name":"Bulletin de la Classe des sciences","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1962-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129715121","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":"L'Échelle astronomique des Temps","authors":"J. Cox","doi":"10.3406/barb.1961.68273","DOIUrl":"https://doi.org/10.3406/barb.1961.68273","url":null,"abstract":"","PeriodicalId":296277,"journal":{"name":"Bulletin de la Classe des sciences","volume":"146 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1961-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133506667","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":"La construction actuelle","authors":"F. Campus","doi":"10.3406/barb.1960.68056","DOIUrl":"https://doi.org/10.3406/barb.1960.68056","url":null,"abstract":"","PeriodicalId":296277,"journal":{"name":"Bulletin de la Classe des sciences","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1960-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129357321","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}
Lorsque le chlorure de polyvinyle est soumis à un gradient de tensions, les bandes de déformation convergent vers les régions où la tension est faible et des fissures s'amorcent aux points de convergence
当聚氯乙烯受到应力梯度时，变形带向应力较低的区域收敛，裂纹在收敛点开始。
{"title":"Sur la formation de fissures internes dans le chlorure de polyvinyle soumis à des contraintes","authors":"J. Bauwens, G. Homes","doi":"10.3406/barb.1960.67950","DOIUrl":"https://doi.org/10.3406/barb.1960.67950","url":null,"abstract":"Lorsque le chlorure de polyvinyle est soumis à un gradient de tensions, les bandes de déformation convergent vers les régions où la tension est faible et des fissures s'amorcent aux points de convergence","PeriodicalId":296277,"journal":{"name":"Bulletin de la Classe des sciences","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1960-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115541683","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}
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