Cytoskeleton interactions in the ascus development and sporulation of Sordaria macrospora

1993 ◽  
Vol 104 (3) ◽  
pp. 883-898 ◽  
Author(s):  
C. Thompson-Coffe ◽  
D. Zickler

The organization of actin during meiosis and sporulation in the ascus of the filamentous ascomycete Sordaria macrospora was determined by immunofluorescence without removal of the cell wall. Actin is present as a dense cortical network of microfilaments (MF) and plaques, a perinuclear shell of actin in prophase I of meiosis, and a complex array of MF involved in alignment of prespore nuclei and closure of spore cell membranes. The relationship of actin to the previously examined microtubule system of the ascus was determined by double-label immunofluorescence. The cytoskeletal inhibitors nocodazole, cytochalasin D and 2,3-butanedione monoxime were used to examine the roles of actin and myosin in ascus development. Microfilament and microtubule arrays are interdependant; disruption of one network results in abnormalities in the other. Both microfilaments and actin-myosin interaction are required for separation and migration of duplicated spindle pole bodies, septation and sporulation

Cells ◽  
2018 ◽  
Vol 7 (11) ◽  
pp. 202
Author(s):  
Ralph Gräf

The centrosome is not only the largest and most sophisticated protein complex within a eukaryotic cell, in the light of evolution, it is also one of its most ancient organelles. This special issue of “Cells” features representatives of three main, structurally divergent centrosome types, i.e., centriole-containing centrosomes, yeast spindle pole bodies (SPBs), and amoebozoan nucleus-associated bodies (NABs). Here, I discuss their evolution and their key-functions in microtubule organization, mitosis, and cytokinesis. Furthermore, I provide a brief history of centrosome research and highlight recently emerged topics, such as the role of centrioles in ciliogenesis, the relationship of centrosomes and centriolar satellites, the integration of centrosomal structures into the nuclear envelope and the involvement of centrosomal components in non-centrosomal microtubule organization.


2017 ◽  
Vol 216 (8) ◽  
pp. 2409-2424 ◽  
Author(s):  
Andrew J. Bestul ◽  
Zulin Yu ◽  
Jay R. Unruh ◽  
Sue L. Jaspersen

Microtubule-organizing centers (MTOCs), known as centrosomes in animals and spindle pole bodies (SPBs) in fungi, are important for the faithful distribution of chromosomes between daughter cells during mitosis as well as for other cellular functions. The cytoplasmic duplication cycle and regulation of the Schizosaccharomyces pombe SPB is analogous to centrosomes, making it an ideal model to study MTOC assembly. Here, we use superresolution structured illumination microscopy with single-particle averaging to localize 14 S. pombe SPB components and regulators, determining both the relationship of proteins to each other within the SPB and how each protein is assembled into a new structure during SPB duplication. These data enabled us to build the first comprehensive molecular model of the S. pombe SPB, resulting in structural and functional insights not ascertained through investigations of individual subunits, including functional similarities between Ppc89 and the budding yeast SPB scaffold Spc42, distribution of Sad1 to a ring-like structure and multiple modes of Mto1 recruitment.


Author(s):  
Paul Jones ◽  
Michał Krzyżanowski

‘Identity, Belonging and Migration: Beyond Constructing ‘Others’’, written by Paul Jones and Michael Krzyanowksi, addresses similar themes to the chapter that comes before it by seeking to discourage the uncritical application of the concept of identity, which the authors argue is not always helpful when assessing the relationship of migrants to collectives.


Author(s):  
Mona Chung ◽  
Bruno Mascitelli

This chapter examines Chinese migration and investment into Europe and explores models of migration and investment by identifying the gap between the two. The chapter highlights the major characteristics of Chinese investment and migration into Europe by identifying and separating the investment from Chinese state-owned enterprises (SOEs) and that of private individuals. This triangulation provides scholars and policy makers with a unique scenario. The migration and investment literature has been conducted as two separate and parallel topics. A small number of studies investigate the relationship of the two as one inter-connected relationship. There is even less focus on Chinese migration and investment due to the fact that over the past decade it has been a fast-moving phenomenon because of the speed of Chinese economic development. In addition, China's different political and economic system and its unique state structure adds another layer of complexity for scholars.


1965 ◽  
Vol 5 (42) ◽  
pp. 843-847 ◽  
Author(s):  
Anthony J. Gow ◽  
Robert Rowland

AbstractRecent measurements of snow accumulation on undulating surfaces around “Byrd station”, Antarctica indicate that the undulations are tending to be filled in. These results are discussed in the light of current knowledge of the origin and migration of such features.


1982 ◽  
Vol 16 (1) ◽  
pp. 4-26 ◽  
Author(s):  
Thomas K. Morrison

It has often been suggested that U.S. foreign economic policies, including the areas of aid, trade and investment, could be utilized to influence migration pressures in major sending countries. This study explores the feasibility of this proposition by examining the linkages between these U.S. economic instruments and migration “push” factors. These linkages are shown to be indirect, are often quite complex, and the final impact on migration, except perhaps in the long run, is probably small in most cases.


1998 ◽  
Vol 274 (1) ◽  
pp. H106-H114 ◽  
Author(s):  
Yandong Jiang ◽  
Fred J. Julian

The goal of this study was to test whether the well-known cardiodepressant effect of halothane is caused mainly by depression of the transient increase in intracellular Ca2+ concentration ([Ca2+]i) during a twitch. Intact rat ventricular trabeculae, paced at 0.5 Hz and 30°C with a bathing extracellular Ca2+ concentration ([Ca2+]o) of 2 mM, were used. The [Ca2+]iwas monitored with the use of fura 2 injected into the myoplasm. The sarcoplasmic reticulum (SR) Ca2+content was estimated with the use of rapid cooling (RC)-induced contracture force and Ca2+release. The relationship of the peak [Ca2+]itransient versus peak twitch force obtained with halothane is intermediate between those obtained with lowered [Ca2+]oand varying doses of 2,3-butanedione monoxime. The data indicate that the negative inotropic action of halothane at low (0.18 mM) dose is mainly achieved by reduction in the Ca2+ sensitivity of the contractile apparatus, whereas, at high dose (0.55 mM), halothane acts both by reducing the [Ca2+]itransient and the Ca2+ sensitivity of the contractile system. At moderate (0.37 mM) dose, the effects were midway between low and high doses. With the use of RC contracture force alone, the reduction of SR Ca2+content caused by halothane is overestimated.


The Condor ◽  
1963 ◽  
Vol 65 (3) ◽  
pp. 200-223 ◽  
Author(s):  
James R. King ◽  
Donald S. Farner

1971 ◽  
Vol 50 (3) ◽  
pp. 737-745 ◽  
Author(s):  
David J. McLaughlin

The double centrosome in the basidium of Boletus rubinellus has been observed in three planes with the electron microscope at interphase preceding nuclear fusion, at prophase I, and at interphase I. It is composed of two components connected by a band-shaped middle part. At anaphase I a single, enlarged centrosome is found at the spindle pole, which is attached to the cell membrane. Microtubules mainly oriented parallel to the longitudinal axis of the basidium are present at prefusion, prophase I and interphase I. Cytoplasmic microtubules are absent when the spindle is present. The relationship of the centrosome in B. rubinellus to that in other organisms and the role of the cytoplasmic microtubules are discussed.


Author(s):  
Лаура Альбердовна Нагоева

В рамках данной статьи рассматриваются западнокавказские письменные артефакты: проблемный аспект их изучения, основные тенденции предыдущих исследований, выдвигается гипотеза родства данных артефактов с протописьменными системами культур Восточной Европы и Ближнего Востока. Изучение данных культурных элементов в свете новых археологических данных позволяет рассматривать их как осколки неолитической знаковой системы. Наряду с цивилизационным скачком, произошедшим в неолите (земледелие и сельское хозяйство, крупные поселения и новый общественный уклад, значительно изменивший характер социально-экономических отношений), произошло переосмысление способов передачи и фиксации информации, тем самым образуя фундамент для возникновения протописьменных систем, распространившихся посредством культурной экспансии и миграций на большие территории, в том числе и Западный Кавказ. Также отмечается, что графическая основа кавказских памятников выходит за пределы кавказско-месопотамско-анатолийского ареала, подтверждением чего служит так называемое винчанское письмо. Делается вывод о том, что знаковый фундамент, сформировавшийся в дунайском энеолите, способствовал образованию первых цивилизаций в исследуемом регионе. This paper deals with the Western Caucasus written artifacts: the problematic aspect of their study, the main trends of previous studies, the hypothesis of the relationship of these artifacts with the oldest writing systems of cultures of Eastern Europe and the Middle East. The study of these cultural elements in the light of new archaeological data leads to the conclusion that they can be considered as fragments of the Neolithic sign system, in particular their commonality with the so-called Danube script. Along with the civilizational leap which occurred in the Neolithic (land husbandry and agriculture, large settlements and a new social structure that changed significantly the nature of socio-economic relations), a rethinking of the methods of transmitting and fixing information took place. Thus, the foundation for the emergence of writing systems that spread through cultural expansion and migration to large territories, including the Western Caucasus, was formed. The author also notes that the graphic basis of Caucasus monuments goes beyond the Caucasus-Mesopotamian-Anatolian range, as confirmed by the so-called Vinca script. It is inferred that the glyph foundation formed in the Danube Eneolithic contributed to the formation of the first civilizations in the region under study.


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