scholarly journals Motility of fibronectin receptor-deficient cells on fibronectin and vitronectin: collaborative interactions among integrins [published erratum appears in J Cell Biol 1992 Jul;118(1):217]

1992 ◽  
Vol 116 (2) ◽  
pp. 477-487 ◽  
Author(s):  
J. S. Bauer
Keyword(s):  
Fibronectin Receptor ◽  
Cell Biol ◽  
Collaborative Interactions

Freeze-Fracture Replication in the Ultrastructure of Blue-Green Algae

1967 ◽  
Vol 25 ◽  
pp. 74-75
Author(s):  
L. V. Leak
Keyword(s):  
Cell Wall ◽  
Electron Microscope ◽  
Green Algae ◽  
Three Dimensional ◽  
Freeze Fracture ◽  
Electron Microscopic ◽  
Photosynthetic Membranes ◽  
Blue Green Algae ◽  
Cell Biol ◽  
Cellular Components

Electron microscopic observations of freeze-fracture replicas of Anabaena cells obtained by the procedures described by Bullivant and Ames (J. Cell Biol., 1966) indicate that the frozen cells are fractured in many different planes. This fracturing or cleaving along various planes allows one to gain a three dimensional relation of the cellular components as a result of such a manipulation. When replicas that are obtained by the freeze-fracture method are observed in the electron microscope, cross fractures of the cell wall and membranes that comprise the photosynthetic lamellae are apparent as demonstrated in Figures 1 & 2.A large portion of the Anabaena cell is composed of undulating layers of cytoplasm that are bounded by unit membranes that comprise the photosynthetic membranes. The adjoining layers of cytoplasm are closely apposed to each other to form the photosynthetic lamellae. Occassionally the adjacent layers of cytoplasm are separated by an interspace that may vary in widths of up to several 100 mu to form intralamellar vesicles.

Learning to Collaborate

2017 ◽  
Author(s):  
Kevin J. S. Zollman
Keyword(s):  
Computer Simulations ◽  
Collaborative Group ◽  
Collaborative Groups ◽  
Collaborative Interactions ◽  
The Cost

This article presents a rudimentary model of collaboration with the aim to understand the conditions under which groups of scientists will endogenously form optimal collaborative groups. By analyzing the model with computer simulations, I uncover three lessons for collaborative groups. First, in reducing the cost borne by scientists from collaborating, one benefits the members of the group. Second, increasing the number of potential collaborative partners benefits all those involved in a collaborative group. Finally and counter intuitively, this model suggests that groups do better when scientists avoid experimenting with new collaborative interactions.

Inclusion of L2 (Basque) learners in Dialogic Literary Gatherings in a linguistically diverse context

2021 ◽  
pp. 136216882199414
Author(s):  
Maite Santiago-Garabieta ◽  
Rocío García-Carrión ◽  
Harkaitz Zubiri-Esnaola ◽  
Garazi López de Aguileta
Keyword(s):  
Second Language ◽  
Language Learning ◽  
Teaching And Learning ◽  
Linguistic Diversity ◽  
Linguistically Diverse ◽  
Educational Systems ◽  
Language Of Instruction ◽  
Dialogic Teaching ◽  
Collaborative Interactions ◽  
Diverse Context

The increasing linguistic diversity of the students in schools poses a major challenge for inclusive educational systems in which everyone can learn the language of instruction effectively and, likewise, can have access to contents, being language the necessary tool to the latter end. Research suggests that there is a robust connection between interaction and language acquisition. Therefore, there is a need to identify the forms of interaction that are most effective for that purpose. In this sense, a greater emphasis on dialogic teaching and learning that increases quality interactions among students may facilitate the learning process. The present study analyses the implementation of a dialogue-based educational action called Dialogic Literary Gatherings (DLG) to promote teaching and learning Basque, a minority language, in a linguistically diverse context. Our research is an exploratory case study: 9 lessons were video-recorded and 2 interviews were conducted with a group of students and their teacher respectively. Results suggest that the DLG creates affordances for encouraging participation in collaborative interactions in the second language, promoting the inclusion of L2 learners, and fostering literature competence as well as a taste for the universal literature. We discuss the implications of these findings for second language learning.

scholarly journals The activity status of cofilin is directly related to invasion, intravasation, and metastasis of mammary tumors

2006 ◽  
Vol 173 (3) ◽  
pp. 395-404 ◽  
Author(s):  
Weigang Wang ◽  
Ghassan Mouneimne ◽  
Mazen Sidani ◽  
Jeffrey Wyckoff ◽  
Xiaoming Chen ◽  
...  
Keyword(s):  
Cell Motility ◽  
Cell Invasion ◽  
Actin Polymerization ◽  
Cancer Cell Invasion ◽  
Invasion And Metastasis ◽  
Over Expression ◽  
Cell Biol ◽  
Tumor Cell Motility ◽  
New Strategies

Understanding the mechanisms controlling cancer cell invasion and metastasis constitutes a fundamental step in setting new strategies for diagnosis, prognosis, and therapy of metastatic cancers. LIM kinase1 (LIMK1) is a member of a novel class of serine–threonine protein kinases. Cofilin, a LIMK1 substrate, is essential for the regulation of actin polymerization and depolymerization during cell migration. Previous studies have made opposite conclusions as to the role of LIMK1 in tumor cell motility and metastasis, claiming either an increase or decrease in cell motility and metastasis as a result of LIMK1 over expression (Zebda, N., O. Bernard, M. Bailly, S. Welti, D.S. Lawrence, and J.S. Condeelis. 2000. J. Cell Biol. 151:1119–1128; Davila, M., A.R. Frost, W.E. Grizzle, and R. Chakrabarti. 2003. J. Biol. Chem. 278:36868–36875; Yoshioka, K., V. Foletta, O. Bernard, and K. Itoh. 2003. Proc. Natl. Acad. Sci. USA. 100:7247–7252; Nishita, M., C. Tomizawa, M. Yamamoto, Y. Horita, K. Ohashi, and K. Mizuno. 2005. J. Cell Biol. 171:349–359). We resolve this paradox by showing that the effects of LIMK1 expression on migration, intravasation, and metastasis of cancer cells can be most simply explained by its regulation of the output of the cofilin pathway. LIMK1-mediated decreases or increases in the activity of the cofilin pathway are shown to cause proportional decreases or increases in motility, intravasation, and metastasis of tumor cells.

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