MICROSCALE ENGINEERING APPLICATIONS IN BONE ADAPTATION

Chapter 1 Viruses as Model Systems in Cell Biology

The field of cellular microbiology is relatively new and incorporates aspects of microbiology and host cellular biology. The first edition of this text, published in 2000, was novel and well received. In general, this new edition is also well written and includes many of the most important recent advances in the field (e.g., microarrays and genome sequencing). The text deals almost exclusively with host cell responses elicited by interactions with pathogens. The editors are top researchers in the field of bacterial cellular microbiology, and they have brought together many new investigators to write chapters in their areas of expertise. The book's first 2 chapters contain topical background information. These chapters thoroughly cover many of the basic concepts in molecular cell biology and introduce all of the various pathogens (bacterial, viral, and eukaryotic) currently being examined in the popular literature. The organization of the subsequent chapters typically alternates between topics in cell biology and bacterial pathogenesis. For example, chapter 11 describes assembly of the cellular cytoskeleton, while chapter 12 describes the mechanisms used by pathogenic bacteria to manipulate the cytoskeleton. Subsequent chapters provide good coverage of bacterial secretion systems, toxins, and their interactions with the host immune system. Generally, the figures, diagrams, and drawings are well chosen, and the tables contain sufficient detail to demonstrate critical points. This is particularly true for chapters 4–6, which describe the host cell surface properties, how pathogenic bacteria adhere to and enter the host cell, and ultimately how the pathogen induces various types of cell signaling. The final chapters focus on new methods of identifying virulence genes and the use of nonvertebrate hosts, such as plants and insects, to model mammalian infections. This book has only a few drawbacks. For example, the first 2 introductory chapters are too detailed. In subsequent chapters, the emphasis is placed on bacterial pathogens; only 1 chapter is dedicated to viruses and none to eukaryotic pathogens (only the introductory paragraphs in chapter 1) or to nonpathogenic microorganisms of any kind. This volume will be an important addition to the resources available to students and researchers in general cell biology or microbiology. Perhaps Internet interactive companion programs and accompanying CDs would be useful with future editions. Because the field is moving so quickly, the authors might consider more frequent updates.

The opportunistic intracellular bacterial pathogen Listeria monocytogenes has in 30 years emerged as an exceptional bacterial model system in infection biology. Research on this bacterium has provided considerable insight into how pathogenic bacteria adapt to mammalian hosts, invade eukaryotic cells, move intracellularly, interfere with host cell functions and disseminate within tissues. It also contributed to unveil features of normal host cell pathways and unsuspected functions of previously known cellular proteins. This review provides an updated overview of our knowledge on this pathogen. In many examples, findings on L. monocytogenes provided the basis for new concepts in bacterial regulation, cell biology and infection processes.

<p>A descriptive study of future teacher students’ mental models of essential concepts in Cell Biology was carried out through explanatory mixed-methods. Some students (n=40) of Biology Education Universitas Negeri Semarang were involved as the research subject. We used a diagnostic test, structured interview guides, and field notes to describe students’ mental model. In the early stage, we prepare a diagnostic test performed essential concepts of Cell Biology. Secondly, we define students’ mental models map based on their answers. Thirdly, we identify factors which affect students’ mental models. Exploration of mental models was conducted through structured interviews with students representing each category. The interview focused on reasoning and argumentation students’ abilities in answering the question on the test item. The research finding describes that students’ mental model in Cell Biology is grouped into three categories, macro-mental to think based of basic content, micro-mental in correlation of content, and intuitive-mental or misconception. This finding can be used in improving research-based learning in Cell Biology.</p>

Cell biology is the basic concept of biology that focuses on the Structure and functions of the Cell.It is therefore a pre requisite for understanding of Biology, a subject that is not only applicable in our daily lives but also key in the research and the production world.Despite the role of biology, failure rate in the subject remains high.The aim of this study was to determine the effect of 5E instructional model on academic achievement in cell biology concepts among students of biology in Vihiga County, Kenya.Effectiveness of the 5E model on improvement of various science outcome has been supported by research conducted in schools.Mixed method research design comprising of quasi-experimental design and focus-group interviews was used.A sample of 550 students and 12 teachers of biology was selected using multi-stage sampling procedure.Data was collected using two achievement tests and an interview schedule guide.The reliability of the research instruments was determined using Cronbach's alpha coefficients while validity was established through consultation with research experts and practicing teachers.Data was analyzed using the independent sample t-test, at = 0.05.The main finding was that the 5E instructional model greatly improved student's academic achievement in cell biology concepts and additionally, it increased student's interest in the subject.It was therefore concluded that the 5E instructional model improved students' academic achievement in cell biology concepts.The results of this study may provide a basis for improving instruction in biology as well as in other subjects to realize improved achievement by the learners.

Hematopoietic stem cells (HSCs) are able clonally and persistently to produce all blood cells while maintaining the HSC pool size, permitting sustained hematopoiesis throughout life. HSCs have served as an excellent model in stem cell biology, and HSC transplantation has served as a prototype for stem cell therapy in regenerative medicine. The research field of stem cell biology and regenerative medicine has been conceptually and practically established through the study of HSCs. After many years of work, we have finally begun to understand self-renewal and multilineage differentiation in HSCs at the molecular level. This chapter briefly introduces how particular molecules play roles in HSC function and regulation. The principles of HSC biology, however, are the focus of this review, which provides an overview of basic concepts in stem cell biology with reference to some historic work.

Liquid-liquid phase separation (LLPS) is a burgeoning concept in cell biology, which was associated with miRISC machinery. However, most studies about LLPS are based on overexpression of core proteins, which is far away from nature condition of cells, whether miRISC underwent LLPS under biological condition remains unknown. Taking miR-490-3p and its target CDK1 as an example, we revealed without overexpression of any protein components, miRISC functioned in an LLPS-depend manner. We firstly found miRISC has liquid-like properties in colon cancer (CC) cells and could fulfill common LLPS criteria under overexpression condition. Then, RIP was performed to confirm miR-490-3p is actually functioning in miRISC. RT-qPCR, western blot and luciferase assays were performed and found miR-490-3p could significantly decrease expression of CDK1 in both RNA and protein levels. However, without overexpression of miRISC components, when treating CC cells with 1,6-hexanediol(1,6-HD), a widely used LLPS inhibitor, the silence effects of miR-490-3p to CDK1 were totally abolished, no matter in RNA, protein or luciferase levels, suggesting that miRISC functions in an LLPS-depend way under biological condition. In conclusion, we found miR-490-3p could silence CDK1 to inhibit the proliferation of CC cells in an LLPS-depend manner.

Two emerging concepts in cell biology are the back-and-forth trafficking of receptor proteins and nuclear transcription factors between the nucleus and the cell membrane, and the alternative splicing of messenger RNA to produce similar proteins targeted to different cell sites. Recent evidence suggests that the nucleolus is a dynamic structure whose components may be involved in both types of trafficking. In the nervous system of higher animals, the N-methyl-D-aspartate (NMDA)-specific glutamate receptor has various roles in development and cell communication. It is involved in learning, memory, axonal guidance and nerve regeneration. We have reported earlier that the NR1 subunit of the NMDA receptor is present in the cell periphery and the nucleus of stem cells, neurons and epitheliomuscular cells of the early-evolved cnidarian, Hydra vulgaris (Scappaticci et al., 2004. Cell Tissue Res 316:263-270); it is involved in coordinating hydra's neuroeffector systems (Kass-Simon and Scappaticci, 2003. Hydrobiologia 530/531:67-71; Pierobon et al., 2004. Eur J Neurosci 20:2598-2604; Scappaticci and Kass-Simon, 2008. Comp Biochem Physiol A 150:415-422; Kay and Kass-Simon, 2009. Bio Bull 216:113-129). Here we report immunocytochemical experiments, using a mouse monoclonal antibody raised against the mammalian NR1 receptor subunit, and an in silico genomic and gene expression analysis identifying the homologues in hydra of mammalian NR1 and fibrillarin (FBL) genes, and their expressed proteins. The experiments reveal that the NR1 antibody specifically labels the nucleoli of large and small interstitial cells (stem cells), nematoblasts, neuroblasts, and epitheliomusclar cells; antibody labeling of the nucleolar marker, FBL, confirms the nucleolar localization of NR1 antibody labeling. Genomic analysis reveals that NR1 and FBL genes are conserved in hydra, and suggests that there are at least two NR1 splice variants, one of which contains both nuclear and nucleolar targeting signals. The finding that an NR1 receptor subunit (or a portion of it) appears in nucleoli of hydra cells is unique, and has not been reported for any other organism. Its presence in nucleoli of hydra may signal the existence of a yet-undescribed shuttle mechanism between the cell surface and the nucleous, or the alternative deployment of NR1 splice variants to different cell sites.

BOOK REVIEWS Ultrastructural Pathology of the Cell and Matrix. By Feroze N. Ghadially. 2d ed. rev. London and Boston: Butterworths, 1982. Pp. xx+971. $240.00. The revised and enlarged second edition of Ghadially's book on ultrastructural pathology is a superb work both in text and illustrations. It is concerned primarily with organelle pathology, while the practical application of ultrastructural studies in clinical diagnosis is demonstrated in Ghadially's second textbook, Diagnostic Electron Microscopy of Tumors (Butterworths, 1980). The book is consistendy well organized. The text is on die left page, widi die corresponding illustrations on the facing page. The book's 17 chapters are divided into numerous well-defined sections. The second edition contains a new chapter on extracellular matrix and 56 new sections concerned with various types of secretory granules, specialized forms of endoplasmic reticulum, bodies of lysosomal storage diseases, intracytoplasmic inclusions, and viruses. Organelles of neoplastic cells are not overlooked. Only a few topics, such as classification of vacuoles and use of the thickness of the limiting membrane in the identification of organelles and in die differential diagnosis of lesions, could be added. Most sections foUow die same logical pattern: definition, nomenclature, correlation with light microscopy, history, description, enumeration of previous reports with references and interpretations of lesions. The nomenclature in ultrastructural padiology in the past was confusing. A single structure would often have several different names, and, alternatively, the same name would be applied to different structures. Ghadially attempts to standardize the nomenclature by simultaneously defining and illustrating pathological entities. In this regard, one picture is certainly worth a thousand words. He selects and occasionally creates names that he considers to be most appropriate. Yet in a few instances , the terminology may be expected to develop further, particularly where die nomenclature is influenced by previous biochemical (e.g. lysosome), functional (e.g. intracisternal sequestration), and developmental (e.g. autophagy) terms. The book contains nearly 3,500 references. The occurrence of each lesion is documented by numerous references to previous reports. References to reviews are used when a widely studied structure, such as a lysosome, is discussed. This, however, obscures historical priorities of bodi discovery and development of concepts. The 885 photographs are well chosen to illustrate the lesions described. They are of excellent technical quality and high aesthetic value. Permission to reprint a book review printed in diis section may be obtained only from die author. 506 J Book Reviews Ghadially's book is more than an atlas and a reference book. In spite ofits size, it is a concise and easily understandable textbook. It establishes a specific terminology which strengthens die reputation of ultrastructural pathology as an exact science. Until recently, biochemistry enjoyed excessive prestige, while morphological investigations had to constantlyjustify dieir existence. Many important concepts in cell biology (e.g. autophagy, muscle contraction) are based on correlation of structure and biochemistry. AU the thousands of forms illustrated in Ghadially's book are undoubtedly associated widi yet unknown chemical composition and processes. The research biochemist should be challenged by this variety of structure and routinely include ultrastructural studies widi each biochemical study he performs. Zdenek Hruban Department ofPathology University ofChicago Letters to a YoungDoctor. By Richard Selzer. New York: Simon & Schuster, 1982. Pp. 205. $13.95. Literature and medicine have always enjoyed a symbiotic relationship. Literature has often employed illness as a major theme and doctors as main characters. Suffering and healing are popular literary subjects. Likewise, many medical professionals have significantly contributed to world literature. The tradition of the physician-writer includes Rabelais, Anton Chekhov, Oliver Wendell Holmes, Arthur Conan Doyle, A. J. Cronin, William Carlos Williams, and Somerset Maugham. This plethora of dual professionalists may at first glance appear unusual, but upon closer inspection it becomes apparent diat many of the qualities necessary for the good physician are also necessary attributes of the good writer—such as refined powers of observation, dedication, intellectual curiosity, sensitivity, and compassion. A medical career is a window to human nature. As such, a medical practice offers an infinite opportunity to develop characters, plot, and theme. In recent years an entire corps of talented physician-writers have emerged, including Michael Crichton, Walker Percy, Robin Cook, and Richard...

CellBio-X: celebrating the interface between Cell Biology and other disciplines

Xenopus has proven to be a remarkably versatile model organism in the realm of biological research for numerous years, owing to its straightforward maintenance in laboratory settings and its abundant provision of ample-sized oocytes, eggs, and embryos. The cell cycle of these oocytes, eggs, and early embryos exhibits synchrony, and extracts derived from these cells serve various research purposes. Many fundamental concepts in biochemistry, cell biology, and development have been elucidated through the use of cell-free extracts derived from Xenopus cells. Over the past few decades, a wide array of cell-free extracts has been prepared from oocytes, eggs, and early embryos of different Xenopus species at varying cell cycle stages. Each of these extracts possesses distinct characteristics. This review provides a concise overview of the Xenopus species employed in laboratory research, the diverse types of cell-free extracts available, and their respective properties. Furthermore, this review delves into the extensive investigation of spindle assembly in Xenopus egg extracts, underscoring the versatility and potency of these cell-free systems in the realm of cell biology.

The study examined the impact of interactive smart board instructional strategy on students' academic performance in cell biology concept. The study mainly targeted senior secondary students in Maiduguri, Borno State. The study adopts a quasi-experimental design, particularly the pre-test-post-test, for the study. The population comprised all 5,936 SS2 Biology students from public schools’ senior secondary schools in Maiduguri Metropolis. A sample of 125 students from two randomly selected schools was used for the study. The group were divided into an experimental group using an Interactive Smart board and a control group/lecture Method. The Cell Biology Performance Test (CBPT) was used for data collection. (CBPT) was duly validated with a reliability coefficient of 0.90 which was subjected to the Pearson Product Moment Correlation (PPMC). Two research questions and two null hypotheses were formulated to guide the study. Inferential statistics were used to test the null hypotheses at a 0.05 level of significance. Results obtained from data analysis showed students in the experimental grouped performed significantly better than those in control group. Also, there was no significant difference between the performance of male and female students taught biology using Interactive smart board. Based on the findings of this study, it was recommended that biology teachers should effectively make use of an Interactive Smart board in teaching irrespective of gender. In addition, qualified teachers who are already in the field and are not knowledgeable in the act of production and use of Interactive SMART Board technology should be re-trained through seminars, workshops, and conferences.

This article presents our experience on teaching biochemical sciences through an innovative approach that integrates concepts of molecular cell biology and protein chemistry. This original laboratory exercise is based on the preparation of an affinity chromatography column containing F-actin molecules immobilized on chitin particles for purifying skeletal myosin II. It favors the active learning of protein extraction and purification, the learning of concepts such as muscle contraction, cytoskeleton structure, and its importance for the living cell. This laboratory exercise also promotes learning biotechnological applications of chitin and the applications of protein immobilization in different industrial fields. Furthermore, the activities target the development of laboratorial abilities, problem-solving skills, and the ability to write a scientific report, following the model of a scientific article. The trials are mainly proposed for either an undergraduate project for advanced students in the life sciences or a postgraduate practical training course. In both the cases, the students must have had biochemistry as part of their regular curriculum. Alternatively, the affinity chromatography method can fit in any regular biochemistry course if active chitin, F-actin, and a myosin II extract are provided. It is very important to mention that this laboratory exercise can be used even in places where a facility such as ultracentrifugation is lacking. For that, the steps of actin purification are skipped, and actin is commercially obtained. Therefore, it is an adequate approach for the active learning of biochemical and molecular cell biology principles and techniques even in poor countries.

The exploding number of computational models produced by Systems Biologists over the last years is an invitation to structure and exploit this new wealth of information. Researchers would like to trace models relevant to specific scientific questions, to explore their biological content, to align and combine them, and to match them with experimental data. To automate these processes, it is essential to consider semantic annotations, which describe their biological meaning. As a prerequisite for a wide range of computational methods, we propose general and flexible similarity measures for Systems Biology models computed from semantic annotations. By using these measures and a large extensible ontology, we implement a platform that can retrieve, cluster, and align Systems Biology models and experimental data sets. At present, its major application is the search for relevant models in the BioModels Database, starting from initial models, data sets, or lists of biological concepts. Beyond similarity searches, the representation of models by semantic feature vectors may pave the way for visualisation, exploration, and statistical analysis of large collections of models and corresponding data.

Natural killer (NK) cells are lymphocytes capable of cytotoxicity against virally infected cells and tumor cells. The display of effector function by NK cells is the result of interactions between germline encoded activating/inhibitory NK cell receptors and their ligands (major histocompatibility complex class I, major histocompatibility complex class I-like, viral, and cellular stress-related surface molecules) expressed on target cells. Determination of NK cell number and function is a common element of the immunotoxicology assessment paradigm for the development of certain classes of pharmaceuticals across a range of modalities. This article summarizes the evidence associating NK cell dysfunction with infectious and cancer risks, reviews emerging NK cell biology, including the impact of immunogenetics on NK cell education and function, and provides perspectives about points to consider when assessing NK cell function in different species in the context of safety assessment.