Cytobiologie最新文献_第4页

Electron microscopic studies on the macronuclear development in the ciliate Chilodonella uncinata. 纤毛虫大核发育的电镜研究。

Cytobiologie Pub Date : 1978-10-01

C K Pyne

{"title":"Electron microscopic studies on the macronuclear development in the ciliate Chilodonella uncinata.","authors":"C K Pyne","doi":"","DOIUrl":"","url":null,"abstract":"The development of macronuclear anlage in the ciliate Chilodonella uncinata has been studied through electron microscopy. The ultrastructure of macro- and micronuclei is described for comparison. During the first stage of development, when the DNA content of the macronuclear anage increases from 2 C to 32 C, chromosomes are visible as distinct osmiophilic bodies inside the anlage. At the end of the initial polyploidization phase, the chromosomes despiralize, giving rise to long filamentous structures 25 to 50 nm in diameter. The latter show a singular banding pattern, with dense bands 12 to 25 nm thick alternating regularly with less dense interbands. Such an organization has not yet been observed in any other type of nucleus. These filamentous structures have been interpreted as highly despiralized oligotenic chromosomes. During the final stage of macronuclear development, these structures condense into thin chromatin strands and small dense granules; the number of granules increases progressively as the chromatin strands disappear. These small granules very likely fuse amongst themselves to form the chromatin granules of the vegetative macronucleus. No evidence has yet been found for a fragmentation of chromatin in this ciliate, but this problem needs further study. The old macronucleus maintains a normal ultrastructure until a late stage of development of the macronuclear anlage, becoming pycnotic only towards the very end of the latter process.","PeriodicalId":75770,"journal":{"name":"Cytobiologie","volume":"18 1","pages":"145-60"},"PeriodicalIF":0.0,"publicationDate":"1978-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11321335","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

Chromatin activation in peritoneal exudate leukocytes after fusion with L cell cytoplasts. 与L细胞质融合后腹膜渗出性白细胞的染色质活化。

Cytobiologie Pub Date : 1978-10-01

A A Kushch, I A Prudowskii, A V Zelenin

引用次数: 0

Large scale perfusion culture of cells growing on surfaces with automatic gas and medium control. 在自动气体和培养基控制下在表面生长的细胞的大规模灌注培养。

Cytobiologie Pub Date : 1978-10-01

E Harms, J Wendenburg

引用次数: 0

Reaction of the contractile apparatus in Physarum to injected Ca++, ATP, ADP and 5'AMP. 绒泡菌收缩器对注入Ca++、ATP、ADP和5'AMP的反应。

Cytobiologie Pub Date : 1978-10-01

T Ueda, K Götz von Olenhusen, K E Wohlfarth-Bottermann

{"title":"Reaction of the contractile apparatus in Physarum to injected Ca++, ATP, ADP and 5'AMP.","authors":"T Ueda, K Götz von Olenhusen, K E Wohlfarth-Bottermann","doi":"","DOIUrl":"","url":null,"abstract":"After replacement of endoplasm by artificial media, the ectoplasmic tube of the plasmodial veins survives and contraction automaticity continues. Motive force generation for plasmodial locomotion is widely independent of the presence of endoplasm, i.e. force generation is located within the ectoplasmic tube. The replacement of endoplasm offers the possibility to study the effects of physiologically active substances upon the contraction activity of cytoplasmic actomyosin under in vivo conditions. Using different methods for measuring the force output as indicator of the effects of injected substances, the influences of free Ca++-ions and different nucleotides were studied. The injection of Ca++ buffers revealed that force output of the veins increased with ascending Ca++ concentrations between 2 x 10(-7) and 10(-6) M. Half maximal response was found to lie in the range of 4 x 10(-7) M, the saturation value at 6 x 10(-7) M Ca++. The injection of adenosine nucleotides induced optimal contraction responses at 0.2 mM ATP, 0.5 mM ADP and 2.5 mM 5'AMP, respectively. The contraction response induced by 0.2 mM ATP depends strongly on the concentration of the available Ca++. From a threshold concentration of 2 x 10(-7) M Ca++, force output increased up to 10(-5) M Ca++. In presence of 0.2 mM ATP, the value for half maximal contraction response to Ca++ was 10(-6) M Ca++. It is concluded that 0.2 mM ATP and 2 to 4 x 10(-7) M Ca++, are the conditions, under which the cytoplasmic actomyosin system of Physarum performs its function in vivo. The implication of the results and the possibilites of the new method for further investigations of the contraction physiology of Physarum as a model system for cytoplasmic actomyosin are discussed.","PeriodicalId":75770,"journal":{"name":"Cytobiologie","volume":"18 1","pages":"76-94"},"PeriodicalIF":0.0,"publicationDate":"1978-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11911582","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

The occurrence of enzymes involved in phenylpropanoid metabolism in the tapetum fraction of anthers. 花药绒毡层中参与苯丙素代谢的酶的发生。