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‣ Cell death and lumen formation in spheroids of MCF-7 cells

AMARAL, Jonatas Bussador do; URABAYASHI, Marcel Shiniti; MACHADO-SANTELLI, Glaucia Maria
Fonte: ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD Publicador: ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD
Tipo: Artigo de Revista Científica
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3D (three-dimensional) cell culture permits a more integrated analysis of the relationship between cells, inserting them into a structure more closely resembling the cellular microenvironment in vivo. The development of in vitro parameters to approximate in vivo 3D cellular environments makes a less reductionist interpretation of cell biology possible. For breast cells, in vitro 3D culture has proven to be an important tool for the analysis of luminal morphogenesis. A greater understanding of this process is necessary because alterations in the lumen arrangement are associated with carcinogenesis. Following lumen formation in 3D cell culture using laser scanning confocal microscopy, we observed alterations in the arrangement of cytoskeletal components (F-actin and microtubules) and increasing levels of cell death associated with lumen formation. The formation of a polarized monolayer facing the lumen was characterized through 3D reconstructions and the use of TEM (transmission electron microscopy), and this process was found to occur through the gradual clearing of cells from the medullary region of the spheroids. This process was associated with different types of cell death, such as apoptosis, autophagy and entosis. The present study showed that changes in the extracellular matrix associated with long periods of time in 3D cell culture lead to the formation of a lumen in MCF-7 cell spheroids and that features of differentiation such as lumen and budding formation occur after long periods in 3D culture...

‣ Establishing a cell biology platform: isolation and preservation of human blood products

Marques, Graça Susete Costa de Carvalho
Fonte: Faculdade de Ciências e Tecnologia Publicador: Faculdade de Ciências e Tecnologia
Tipo: Dissertação de Mestrado
Publicado em //2014 Português
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Dissertação para obtenção do Grau de Mestre em Genética Molecular e Biomedicina; The use of human primary cells provide researchers in different areas with irrefutable more biologically relevant data than using cell lines or animal blood cells. The work was performed in the scope of the Cell Biology Services @ CEDOC, aiming to provide viable and trustful human primary cells and products. We had three main objectives: protocol optimizations for blood cell isolation, culture and cryopreservation; cost estimation and divulgation of the services. We have reviewed standard protocols and compared different strategies for blood cell isolation. The impact of those methodologies was evaluated regarding cell yield and purity, cell functional characteristics and cost. We also developed a method for serum isolation from human plasma in blood buffy coats. The resultant sera were sterile and suitable to be used in leukocyte cultures. Different protocols for T cells isolation were compared: positive versus negative immunomagnetic selection and isolation using nylon wool fiber columns. Positive selection provided the highest isolation yield (32.35%), while negatively selected cells had the highest purity (92.81%). Although nylon wool fiber column was the fastest and cheapest method...

‣ Epigenetic Regulation of the Stem Cell Mitogen Fgf-2 by Mbd1 in Adult Neural Stem/Progenitor Cells*S⃞

Li, Xuekun; Barkho, Basam Z.; Luo, Yuping; Smrt, Richard D.; Santistevan, Nicholas J.; Liu, Changmei; Kuwabara, Tomoko; Gage, Fred H.; Zhao, Xinyu
Fonte: American Society for Biochemistry and Molecular Biology Publicador: American Society for Biochemistry and Molecular Biology
Tipo: Artigo de Revista Científica
Publicado em 10/10/2008 Português
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Whether and how mechanisms intrinsic to stem cells modulate their proliferation and differentiation are two central questions in stem cell biology. Although exogenous basic fibroblast growth factor 2 (FGF-2/Fgf-2) is commonly used to expand adult neural stem/progenitor cells (NSPCs) in vitro, we do not yet understand the functional significance or the molecular regulation of Fgf-2 expressed endogenously by adult NSPCs. We previously demonstrated that methylated CpG binding protein 1 (MBD1/Mbd1) is a transcriptional repressor of Fgf-2 and is enriched in adult brains. Mbd1 deficiency in mice selectively affected adult neurogenesis and the differentiation of NSPCs. Here we show that an Mbd1 and DNA methylation-mediated epigenetic mechanism regulated the expression of stem cell mitogen Fgf-2 in adult NSPCs. Mbd1 bound to the Fgf-2 promoter and regulates its expression in adult NSPCs. In the absence of functional Mbd1, the Fgf-2 promoter was hypomethylated, and treatment with a DNA methylation inhibitor resulted in increased Fgf-2 expression in adult NSPCs. We further demonstrated that both acute knockdown of Mbd1 or overexpression of Fgf-2 in adult NSPCs inhibited their neuronal differentiation, which could be responsible for the neurogenic deficits observed in Mbd1-deficient mice. These data indicate that intrinsic epigenetic mechanisms play critical roles in the regulation of adult NSPC functions.

‣ Kruppel-like Factor 4 (Klf4) Prevents Embryonic Stem (ES) Cell Differentiation by Regulating Nanog Gene Expression*

Zhang, Peilin; Andrianakos, Rose; Yang, Yang; Liu, Chunming; Lu, Wange
Fonte: American Society for Biochemistry and Molecular Biology Publicador: American Society for Biochemistry and Molecular Biology
Tipo: Artigo de Revista Científica
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Transcription factor Kruppel-like factor 4 (Klf4) is essential for somatic cell reprogramming. In addition, Klf4 seems to play a redundant role along with other Klf family proteins in embryonic stem (ES) cell self-renewal. However, how Klf4 regulates ES cell self-renewal and somatic cell reprogramming is still poorly understood. Here we report that Klf4 is required for both ES cell self-renewal and maintenance of pluripotency and that the expression of Klf4 prevents ES cell differentiation in response to withdrawal of leukemia inhibitory factor (LIF) or bone morphogenetic protein 4 (BMP4). In addition, Klf4 directly binds to the promoter region of Nanog and regulates its expression. Expression of Nanog prevents ES cell differentiation even when Klf4 gene expression is knocked down. On the other hand, knockdown of Nanog expression induces differentiation of ES cells that overexpress Klf4. Taken together, these results demonstrate that Klf4 functions upstream of Nanog in ES cell self-renewal and in preventing ES cell differentiation.

‣ High Temperature Requirement A3 (HtrA3) Promotes Etoposide- and Cisplatin-induced Cytotoxicity in Lung Cancer Cell Lines*

Beleford, Daniah; Rattan, Ramandeep; Chien, Jeremy; Shridhar, Viji
Fonte: American Society for Biochemistry and Molecular Biology Publicador: American Society for Biochemistry and Molecular Biology
Tipo: Artigo de Revista Científica
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Lung cancer is the leading cause of cancer-related deaths worldwide. Here we show for the first time that HtrA3 is a mitochondrial stress-response factor that promotes cytotoxicity to etoposide and cisplatin in lung cancer cell lines. Exogenous expression of wild type HtrA3 domain variants significantly attenuated cell survival with etoposide and cisplatin treatment in lung cancer cell lines H157 and A549 compared with expression of protease inactive mutants (S305A) or vector control. Conversely, HtrA3 suppression promoted cell survival with etoposide and cisplatin treatment in lung cancer cell lines Hop62 and HCC827. Survival was attenuated by re-expression of wild type HtrA3 variants during treatment but not by protease inactive mutants or vector control. HtrA3 also co-fractionated and co-localized with mitochondrial markers with both endogenous and exogenous expression in normal lung and lung cancer cell lines but was translocated from mitochondria following etoposide treatment. Moreover, HtrA3 translocation from mitochondria correlated with an increase in cell death that was attenuated by either HtrA3 suppression or Bcl-2 overexpression. Taken together, these results suggest that HtrA3 may be a previously uncharacterized mitochondrial cell death effector whose serine protease function may be crucial to modulating etoposide- and cisplatin-induced cytotoxicity in lung cancer cell lines.

‣ Rac1 Recruits the Adapter Protein CMS/CD2AP to Cell-Cell Contacts

van Duijn, Trynette J.; Anthony, Eloise C.; Hensbergen, Paul J.; Deelder, André M.; Hordijk, Peter L.
Fonte: American Society for Biochemistry and Molecular Biology Publicador: American Society for Biochemistry and Molecular Biology
Tipo: Artigo de Revista Científica
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Rac1 is a member of the Rho family of small GTPases, which regulate cell adhesion and migration through their control of the actin cytoskeleton. Rho-GTPases are structurally very similar, with the exception of a hypervariable domain in the C terminus. Using peptide-based pulldown assays in combination with mass spectrometry, we previously showed that the hypervariable domain in Rac1 mediates specific protein-protein interactions. Most recently, we found that the Rac1 C terminus associates to the ubiquitously expressed adapter protein CMS/CD2AP. CD2AP is critical for the formation and maintenance of a specialized cell-cell contact between kidney podocyte foot processes, the slit diaphragm. Here, CD2AP links the cell adhesion protein nephrin to the actin cytoskeleton. In addition, CMS/CD2AP binds actin-regulating proteins, such as CAPZ and cortactin, and has been implicated in the internalization of growth factor receptors. We found that CD2AP specifically interacts with the C-terminal domain of Rac1 but not with that of other Rho family members. Efficient interaction between Rac1 and CD2AP requires both the proline-rich domain and the poly-basic region in the Rac1 C terminus, and at least two of the three N-terminal SH3 domains of CD2AP. CD2AP co-localizes with Rac1 to membrane ruffles...

‣ miR-10b Targets Tiam1: IMPLICATIONS FOR Rac ACTIVATION AND CARCINOMA MIGRATION

Moriarty, Charlotte H.; Pursell, Bryan; Mercurio, Arthur M.
Fonte: American Society for Biochemistry and Molecular Biology Publicador: American Society for Biochemistry and Molecular Biology
Tipo: Artigo de Revista Científica
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Understanding the mechanisms by which specific microRNAs regulate cell migration and invasion is a timely and significant problem in cancer cell biology. miR-10b is of interest in this regard because its expression is altered in breast and other cancers. Our analysis of potential miR-10b targets identified Tiam1 (T lymphoma invasion and metastasis 1), a guanidine exchange factor for Rac. We demonstrate, using an miR-10b synthetic precursor, expression vector, and antisense oligonucleotide, that miR-10b represses Tiam1 expression in breast carcinoma cells and that it interacts with the 3′-UTR of Tiam1. Consistent with the involvement of Tiam1 in cell motility, we observed that miR-10b suppresses the ability of breast carcinoma cells to migrate and invade. Importantly, we demonstrate that miR-10b also inhibits Tiam1-mediated Rac activation. These data provide a mechanism for the regulation of Tiam1-mediated Rac activation in breast cancer cells and need to be considered in the context of other reported functions for miR-10b.

‣ MicroRNA-210 Regulates Cancer Cell Proliferation through Targeting Fibroblast Growth Factor Receptor-like 1 (FGFRL1)*

Tsuchiya, Soken; Fujiwara, Takeshi; Sato, Fumiaki; Shimada, Yutaka; Tanaka, Eiji; Sakai, Yoshiharu; Shimizu, Kazuharu; Tsujimoto, Gozoh
Fonte: American Society for Biochemistry and Molecular Biology Publicador: American Society for Biochemistry and Molecular Biology
Tipo: Artigo de Revista Científica
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The importance of microRNAs (miRNAs) in human malignancies has been well recognized. Here, we report that the expression of microRNA-210 (miR-210) is down-regulated in human esophageal squamous cell carcinoma and derived cell lines. Marked decreases in the level of miR-210 were observed especially in poorly differentiated carcinomas. We found that miR-210 inhibits cancer cell survival and proliferation by inducing cell death and cell cycle arrest in G1/G0 and G2/M. Finally, we identified fibroblast growth factor receptor-like 1 (FGFRL1) as a target of miR-210 in esophageal squamous cell carcinoma and demonstrated that FGFRL1 accelerates cancer cell proliferation by preventing cell cycle arrest in G1/G0. Taken together, our findings show an important role for miR-210 as a tumor-suppressive microRNA with effects on cancer cell proliferation.

‣ Structure-Function Analysis of Tetraspanin CD151 Reveals Distinct Requirements for Tumor Cell Behaviors Mediated by α3β1 versus α6β4 Integrin*

Zevian, Shannin; Winterwood, Nicole E.; Stipp, Christopher S.
Fonte: American Society for Biochemistry and Molecular Biology Publicador: American Society for Biochemistry and Molecular Biology
Tipo: Artigo de Revista Científica
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The basement membrane protein laminin-332 (laminin-5) mediates both stable cell adhesion and rapid cell migration and thus has the potential to either restrain or promote tumor cell metastasis. The major cellular receptors for laminin-332 are integrin α3β1, which mediates rapid tumor cell migration, and integrin α6β4, which often mediates stable cell attachment. Tetraspanin protein CD151 interacts directly with both α3β1 and α6β4 integrins and with other tetraspanins, thereby promoting α3β1 and α6β4 association with tetraspanin-enriched microdomains on the cell surface. To explore the possibility of selectively modulating tumor cell responses to laminin-332, we re-expressed a series of CD151 mutants in epidermoid carcinoma cells with near total, RNAi-mediated silencing of endogenous CD151. The interactions of CD151 with its integrin partners or its interactions with other tetraspanins were selectively disrupted by specific mutations in the CD151 large extracellular loop (EC2 domain) or in intracellular CD151 palmitoylation sites, respectively. CD151-integrin association and CD151-tetraspanin association were both important for α3β1 integrin-dependent initial adhesion and rapid migration on laminin-332. Remarkably, however...

‣ Kallikrein-5 Promotes Cleavage of Desmoglein-1 and Loss of Cell-Cell Cohesion in Oral Squamous Cell Carcinoma*

Jiang, Rong; Shi, Zonggao; Johnson, Jeffrey J.; Liu, Yueying; Stack, M. Sharon
Fonte: American Society for Biochemistry and Molecular Biology Publicador: American Society for Biochemistry and Molecular Biology
Tipo: Artigo de Revista Científica
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Oral squamous cell carcinoma (OSCC) ranks among the top 8 causes of cancer death worldwide, with only a 60% 5-year survival rate, highlighting the need for discovery of novel biomarkers and therapeutic targets. We have previously reported that expression of a panel of serine proteinase kallikreins (KLK 5, 7, 8, and 10) is correlated with formation of more aggressive OSCC tumors in a murine orthotopic OSCC model and is elevated in human OSCC. Current studies focus on understanding the potential role of KLK5 in OSCC progression. In initial studies, KLK levels in malignant OSCC cells (SCC25) were compared with cells from normal oral mucosa (OKF/6) and pre-malignant oral keratinocytes (pp126) using qPCR. A marked elevation of all KLKs was observed in aggressive SCC25 cells relative to OKF/6 cells. In normal skin, KLKs are involved in desquamation during epidermal differentiation via proteolytic cleavage of the desmosomal cadherin component desmoglein 1 (Dsg1). As loss of cell-cell cohesion is prevalent in tumor metastasis, Dsg1 integrity was evaluated. Results show that SCC25 cells exhibit cleavage of Dsg1, which is blocked by proteinase inhibitor treatment as well as by siRNA silencing of KLK5 expression. Furthermore, cell-cell aggregation assays demonstrate that silencing of KLK5 enforces cell-cell adhesion; conversely...

‣ Crystal Structure of the cis-Dimer of Nectin-1: IMPLICATIONS FOR THE ARCHITECTURE OF CELL-CELL JUNCTIONS*

Narita, Hirotaka; Yamamoto, Yasunori; Suzuki, Mamoru; Miyazaki, Naoyuki; Yoshida, Asuka; Kawai, Katsuhisa; Iwasaki, Kenji; Nakagawa, Atsushi; Takai, Yoshimi; Sakisaka, Toshiaki
Fonte: American Society for Biochemistry and Molecular Biology Publicador: American Society for Biochemistry and Molecular Biology
Tipo: Artigo de Revista Científica
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In multicellular organisms, cells are interconnected by cell adhesion molecules. Nectins are immunoglobulin (Ig)-like cell adhesion molecules that mediate homotypic and heterotypic cell-cell adhesion, playing key roles in tissue organization. To mediate cell-cell adhesion, nectin molecules dimerize in cis on the surface of the same cell, followed by trans-dimerization of the cis-dimers between the neighboring cells. Previous cell biological studies deduced that the first Ig-like domain of nectin and the second Ig-like domain are involved in trans-dimerization and cis-dimerization, respectively. However, to understand better the steps involved in nectin adhesion, the structural basis for the dimerization of nectin must be determined. In this study, we determined the first crystal structure of the entire extracellular region of nectin-1. In the crystal, nectin-1 formed a V-shaped homophilic dimer through the first Ig-like domain. Structure-based site-directed mutagenesis of the first Ig-like domain identified four essential residues that are involved in the homophilic dimerization. Upon mutating the four residues, nectin-1 significantly decreased cis-dimerization on the surface of cultured cells and abolished the homophilic and heterophilic adhesion activities. These results indicate that...

‣ Cooperative Role of Nectin-Nectin and Nectin-Afadin Interactions in Formation of Nectin-based Cell-Cell Adhesion*

Kurita, Souichi; Ogita, Hisakazu; Takai, Yoshimi
Fonte: American Society for Biochemistry and Molecular Biology Publicador: American Society for Biochemistry and Molecular Biology
Tipo: Artigo de Revista Científica
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The nectin cell adhesion molecules interact in trans with each other through their extracellular regions and with afadin through their cytoplasmic tails, forming adherens junctions in cooperation with cadherins. In a single cell, Necl-5 (nectin-like molecule-5) localizes at the leading edge and regulates directional cell movement in response to a chemoattractant. In such a single cell, afadin also localizes at the leading edge without interacting with nectins or Necl-5. It remains unknown how the nectin-nectin and nectin-afadin interactions are initiated when moving cells contact each other to initiate the formation of adherens junctions. We show here that the Necl-5-nectin interaction induced by cell-cell contact enhances the nectin-afadin interaction. This interaction then enhances the nectin-nectin interaction, which further enhances the nectin-afadin interaction in a positive feedback manner. Thus, the Necl-5-nectin, nectin-nectin, and nectin-afadin interactions cooperatively increase the clustering of the nectin-afadin complex at the cell-cell contact sites, promoting the formation of the nectin-based cell-cell adhesion.

‣ The FAM deubiquitylating enzyme localizes to multiple points of protein trafficking in epithelia, where it associates with E-cadherin and β-catenin; The FAM deubiquitylating enzyme localizes to multiple points of protein trafficking in epithelia, where it associates with E-cadherin and beta-catenin

Murray, R.; Jolly, L.; Wood, S.
Fonte: Amer Soc Cell Biology Publicador: Amer Soc Cell Biology
Tipo: Artigo de Revista Científica
Publicado em //2004 Português
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Ubiquitylation is a necessary step in the endocytosis and lysosomal trafficking of many plasma membrane proteins and can also influence protein trafficking in the biosynthetic pathway. Although a molecular understanding of ubiquitylation in these processes is beginning to emerge, very little is known about the role deubiquitylation may play. Fat Facets in mouse (FAM) is substrate-specific deubiquitylating enzyme highly expressed in epithelia where it interacts with its substrate, β-catenin. Here we show, in the polarized intestinal epithelial cell line T84, FAM localized to multiple points of protein trafficking. FAM interacted with β-catenin and E-cadherin in T84 cells but only in subconfluent cultures. FAM extensively colocalized with β-catenin in cytoplasmic puncta but not at sites of cell-cell contact as well as immunoprecipitating with β-catenin and E-cadherin from a higher molecular weight complex (500 kDa). At confluence FAM neither colocalized with, nor immunoprecipitated, β-catenin or E-cadherin, which were predominantly in a larger molecular weight complex (2 MDa) at the cell surface. Overexpression of FAM in MCF-7 epithelial cells resulted in increased β-catenin levels, which localized to the plasma membrane. Expression of E-cadherin in L-cell fibroblasts resulted in the relocalization of FAM from the Golgi to cytoplasmic puncta. These data strongly suggest that FAM associates with E-cadherin and β-catenin during trafficking to the plasma membrane.; Rachael Z. Murray...

‣ Laser-based microfabrication for cell adhesion and migration

Miller, Jordan S.
Fonte: Universidade Rice Publicador: Universidade Rice
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Mammalian cell adhesion and migration impact a multitude of cellular behaviors and tissue remodeling processes. Over the past several decades, investigators have methodically improved in vitro systems as mimics of the extracellular microenvironment to study these biologic phenomena. Experiments have progressed from early studies on bifunctional inorganic surfaces to those with purified adhesive proteins against an organic, non-adhesive background. Recently, subcellular geometric patterns of adhesive proteins have proven useful to restrict and direct focal contact formation, cell survival, lamellopodia extension, and the maturation of "supermature" focal contacts. The vast majority of recent studies have involved the construction of hydrophobic patches with adsorbed fibronectin as the adhesive constraint of choice. However, the extracellular matrix (ECM) in which cells operate is a complex and diverse environment where numerous signals interact with a cell simultaneously; signals that the cell must integrate and that directly impact these processes. Microfabrication methods to approximate the extracellular milieu have significant limitations in their potential to be extended to pattern multiple bioactive ligands with high precision. Current techniques require multi-step processes which lose feature fidelity at every pattern transfer step...

‣ Criação, aplicação e avaliação de aulas com jogos cooperativos do tipo RPG para o ensino de biologia celular; Creation, application and evaluation of RPG-based classes for cell biology teaching

Marco Antonio Ferreira Randi
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 26/08/2011 Português
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O aluno que se envolve com seu processo de aprendizagem aprende melhor. A partir dessa premissa, nosso objetivo no presente estudo foi desenvolver, aplicar e avaliar uma nova ferramenta didática em disciplinas de Biologia Celular, baseada em aulas com RPG (roleplaying game). O RPG é um sistema de jogo cooperativo onde os participantes têm objetivos comuns e precisam atuar em grupo para alcançá-los. Aplicado à educação, acreditamos que funciona como um facilitador da aprendizagem ativa, sendo o aluno o construtor de seu conhecimento enquanto participa da aula, orientado pelo professor. A criação e aplicação dessas aulas constitui desafio estimulante para professores, e a formação de professores também constituiu foco dentro desse estudo. A metodologia incluiu: pesquisas teóricas sobre o assunto a ser trabalhado na aula (um processo celular como síntese de ATP, por exemplo) e subsequente criação da aula na forma de uma aventura; testes das aulas criadas; aplicação das aulas a alunos de nível superior em diferentes cursos em três diferentes universidades; avaliação dos resultados através de notas em provas regulares das disciplinas, questionários, construção de mapas conceituais, depoimentos dos alunos e dos professores participantes...

‣ Cloning, Stem Cells, and the Current National Debate: Incorporating Ethics into a Large Introductory Biology Course

Fink, Rachel D.
Fonte: The American Society for Cell Biology Publicador: The American Society for Cell Biology
Tipo: Artigo de Revista Científica
Publicado em //2002 Português
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Discussing the ethical issues involved in topics such as cloning and stem cell research in a large introductory biology course is often difficult. Teachers may be wary of presenting material biased by personal beliefs, and students often feel inhibited speaking about moral issues in a large group. Yet, to ignore what is happening “out there” beyond the textbooks and lab work is to do a disservice to students. This essay describes a semester-long project in which upperclass students presented some of the most complex and controversial ideas imaginable to introductory students by staging a mock debate and acting as members of the then newly appointed President's Council on Bioethics. Because the upperclass students were presenting the ideas of real people who play an important role in shaping national policy, no student's personal beliefs were put on the line, and many ideas were articulated. The introductory audience could accept or reject what they were hearing and learn information important for making up their own minds on these issues. This project is presented as an example of how current events can be used to put basic cell biology into context and of how exciting it can be when students teach students.

‣ Continuum Electrostatics in Cell Biology

Gagliardi, L. John
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 06/02/2010 Português
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Recent experiments revealing possible nanoscale electrostatic interactions in force generation at kinetochores for chromosome motions have prompted speculation regarding possible models for interactions between positively charged molecules in kinetochores and negative charge on C-termini near the plus ends of microtubules. A clear picture of how kinetochores establish and maintain a dynamic coupling to microtubules for force generation during the complex motions of mitosis remains elusive. The current paradigm of molecular cell biology requires that specific molecules, or molecular geometries, for force generation be identified. However, it is possible to account for mitotic motions within a classical electrostatics approach in terms of experimentally known cellular electric charge interacting over nanometer distances. These charges are modeled as bound surface and volume continuum charge distributions. Electrostatic consequences of intracellular pH changes during mitosis may provide a master clock for the events of mitosis.; Comment: 16 pages, 1 figure

‣ β-Catenin regulation during the cell cycle: Implications in G2/M and apoptosis

Olmeda, David; Castel, Susanna; Vilaró, Senén; Cano, Amparo
Fonte: American Society for Cell Biology Publicador: American Society for Cell Biology
Tipo: Artículo Formato: 1254187 bytes; application/pdf
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Copyright © by American Society for Cell Biology.-- Final full-text version of the paper available at: http://www.molbiolcell.org/content/vol14/issue7/ .-- Supplementary material available at: http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=165681&blobname=mbc_14_7_2844__.html; β-catenin is a multifunctional protein involved in cell-cell adhesion and Wnt signal transduction. β-Catenin signaling has been proposed to act as inducer of cell proliferation in different tumors. However, in some developmental contexts and cell systems β-catenin also acts as a positive modulator of apoptosis. To get additional insights into the role of β-Catenin in the regulation of the cell cycle and apoptosis, we have analyzed the levels and subcellular localization of endogenous β-catenin and its relation with adenomatous polyposis coli (APC) during the cell cycle in S-phase–synchronized epithelial cells. β-Catenin levels increase in S phase, reaching maximum accumulation at late G2/M and then abruptly decreasing as the cells enter into a new G1 phase. In parallel, an increased cytoplasmic and nuclear localization of β-catenin and APC is observed during S and G2 phases. In addition, strong colocalization of APC with centrosomes, but not β-catenin...

‣ Applications Of Microspectroscopy, Hyperspectral Chemical Imaging And Fluorescence Microscopy In Chemistry, Biochemistry, Biotechnology, Molecular And Cell Biology

I. C. Baianu
Fonte: Nature Preceedings Publicador: Nature Preceedings
Tipo: Manuscript
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Chemical imaging is a technique for the simultaneous measurement of spectra (chemical information) and images or pictures (spatial information)^1,2^. The technique is most often applied to either solid or gel samples, and has applications in chemistry, biology^3-8^, medicine^9,10^, pharmacy^11^ (see also for example: Chemical Imaging Without Dyeing), food science, Food Physical Chemistry, Biotechnology^12,13^, Agriculture and industry. NIR, IR and Raman chemical imaging is also referred to as hyperspectral, spectroscopic, spectral or multi-spectral imaging (also see micro-spectroscopy). However, other ultra-sensitive and selective, chemical imaging techniques are also in use that involve either UV-visible or fluorescence microspectroscopy.

‣ Complex Systems Biology of Organisms

I. C. Baianu
Fonte: Nature Preceedings Publicador: Nature Preceedings
Tipo: Manuscript
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Complex Systems Biology models and theories are axiomatically defined in terms of concrete categories and organismic supercategories (OS) to include both complete self-reproduction of logically defined pi-entities founded in Quine's logic and dynamic system diagrams subject to both algebraic and topological transformations. Mathematical models of complex organisms are expressed in terms of category theory and organismic supercategories (OS). OS theories have applications in: Bioinformatics, Developmental Biology, Genomics and Molecular Cell Biology