Proteome signatures—how are they obtained and what do they teach us?

The dawn of a new Proteomics era, just over a decade ago, allowed for large-scale protein profiling studies that have been applied in the identification of distinctive molecular cell signatures. Proteomics provides a powerful approach for identifying and studying these multiple molecular markers in a vast array of biological systems, whether focusing on basic biological research, diagnosis, therapeutics, or systems biology. This is a continuously expanding field that relies on the combination of different methodologies and current advances, both technological and analytical, which have led to an explosion of protein signatures and biomarker candidates. But how are these biological markers obtained? And, most importantly, what can we learn from them? Herein, we briefly overview the currently available approaches for obtaining relevant information at the proteome level, while noting the current and future roles of both traditional and modern proteomics. Moreover, we provide some considerations on how the development of powerful and robust bioinformatics tools will greatly benefit high-throughput proteomics. Such strategies are of the utmost importance in the rapidly emerging field of immunoproteomics, which may play a key role in the identification of antigens with diagnostic and/or therapeutic potential and in the development of new vaccines. Finally, we consider the present limitations in the discovery of new signatures and biomarkers and speculate on how such hurdles may be overcome, while also offering a prospect for the next few years in what could be one of the most significant strategies in translational medicine research.     

Endothelial development taking shape

Blood vessel development is a vital process during embryonic development, during tissue growth, regeneration and disease processes in the adult. In the past decade researchers have begun to unravel basic molecular mechanisms that regulate the formation of vascular lumen, sprouting angiogenesis, fusion of vessels, and pruning of the vascular plexus. The understanding of the biology of these angiogenic processes is increasingly driven through studies on vascular development at the cellular resolution. Single cell analysis in vivo, advanced genetic tools and the widespread use of powerful animal models combined with improved imaging possibilities are delivering new insights into endothelial cell form, function and behavior angiogenesis. Moreover, the combination of in silico modeling and experimentation including dynamic imaging promotes insights into higher level cooperative behavior leading to functional patterning of vascular networks. Here we summarize recent concepts and advances in the field of vascular development, focusing in detail on the endothelial cell.     

Matrix-assisted laser desorption/ionization imaging mass spectrometry: a promising technique for reproductive research

Matrix-assisted laser desorption/ionization (MALDI) tissue imaging mass spectrometry is particularly promising among the numerous applications of mass spectrometry. It is used for probing and analyzing the spatial arrangement of a wide range of molecules, including proteins, peptides, lipids, drugs, and metabolites, directly in thin slices of tissue. In the field of proteomics, the technology avoids tedious and time-consuming extraction and fractionation steps classically required for sample analysis. MALDI imaging mass spectrometry is increasingly recognized as a powerful method for clinical proteomics, particularly in cancer research. The technology has particular potential for the discovery of new tissue biomarker candidates, classification of tumors, early diagnosis or prognosis, elucidating pathogenesis pathways, and therapy monitoring. Over recent years, MALDI imaging mass spectrometry has been used for molecular profiling and imaging directly in male and female reproductive tissues. This review will consider some of the recent publications in the field, addressing a range of issues covering embryo development, gene expression product profiling during gametogenesis, and seeking and identifying biomarkers of reproductive cancers. The wealth of advances in mass spectrometry imaging will inevitably attract biologists and clinicians as the advantages and power of this technology become more widely known. This review will also discuss bottlenecks and the many technical issues that remain to be resolved before laboratories in the field can adopt the technology. We foresee that MALDI imaging mass spectrometry will have a major impact in reproductive research by opening new avenues to the understanding of various molecular mechanisms and the diagnosis of reproductive pathologies.     

Directed evolution: an evolving and enabling synthetic biology tool

Synthetic biology, with its goal of designing biological entities for wide-ranging purposes, remains a field of intensive research interest. However, the vast complexity of biological systems has heretofore rendered rational design prohibitively difficult. As a result, directed evolution remains a valuable tool for synthetic biology, enabling the identification of desired functionalities from large libraries of variants. This review highlights the most recent advances in the use of directed evolution in synthetic biology, focusing on new techniques and applications at the pathway and genome scale.     

Molecular biology in biorheology

This presentation is aimed at giving some background information on molecular biology, thus serving as an introduction to the Symposium on Molecular Biorheology held during the Sixth International Congress of Biorheology in Vancouver. The papers presented at this Symposium indicate that the use of molecular biological techniques allows the understanding of normal and abnormal rheological properties of cells and organs at the molecular level. It is hoped that these examples will provide an impetus for us to open new frontiers of research in biorheology by taking advantage of the powerful tools developed from recent advances in molecular biology.     

Mini-review: Proactive biomaterials and bone tissue engineering

Recent advances in cell isolation and culture procedures, combined with growing understanding and use of molecular biology and biochemistry techniques, have resulted in the establishment of a new field of biological/biomedical research: cellular and tissue engineering. In the biomaterials field, cell and tissue bioengineers are investigating the development of proactive biomaterials (for example, bioceramics, chemically modified implant metals, and biodegradable tissue scaffolds) which utilize cellular- or molecular-level methods of manipulating cell/tissue behavior in order to encourage clinically desirable biological events at the tissue-implant interface. In vitro investigations utilizing osteoblasts, osteoclasts, and appropriate precursor cells, combined with long-term (i.e., years) tissue engineering studies in vivo are needed to enhance current understanding of the many mechanisms involved in bone formation and regulation. Such understanding will allow the development of proactive biomaterials for use in bone, which can elicit specific, timely, and clinically desirable responses from surrounding cells and tissues. (c) 1996 John Wiley & Sons, Inc.     

Molecular immunology: At the border of centuries and at the interface of disciplines

This is a special issue of the journal Molekulyarnaya biologiya (Molecular Biology) focusing on topical problems in molecular immunology, virology, and the related fields of science, including molecular genetics, biochemistry, and cell biology. Several reviews are offered to the attention of our readers, as well as original experimental papers. This issue was prepared on a tight schedule and, certainly, cannot pretend to cover all the areas of the state-of-the-art science.     

Proteoglycans,key regulators of cell–matrix dynamics

In this special issue of Matrix Biology centered on proteoglycan biology we have assembled a blend of articles focused on the state-of-the-art of proteoglycanology. The field has greatly expanded in the past three decades and now encompasses all the areas of biology. This special issue is divided into five chapters describing hyaluronan metabolism, biosynthetic and catabolic pathways of proteoglycans and their roles in inflammation, cancer, repair and development. We hope that the new original work and the reviews from recognized leaders will stimulate investigations in this exciting and fertile field of research.     

Systems biology in animal sciences

Systems biology is a rapidly expanding field of research and is applied in a number of biological disciplines. In animal sciences, omics approaches are increasingly used, yielding vast amounts of data, but systems biology approaches to extract understanding from these data of biological processes and animal traits are not yet frequently used. This paper aims to explain what systems biology is and which areas of animal sciences could benefit from systems biology approaches. Systems biology aims to understand whole biological systems working as a unit, rather than investigating their individual components. Therefore, systems biology can be considered a holistic approach, as opposed to reductionism. The recently developed 'omics' technologies enable biological sciences to characterize the molecular components of life with ever increasing speed, yielding vast amounts of data. However, biological functions do not follow from the simple addition of the properties of system components, but rather arise from the dynamic interactions of these components. Systems biology combines statistics, bioinformatics and mathematical modeling to integrate and analyze large amounts of data in order to extract a better understanding of the biology from these huge data sets and to predict the behavior of biological systems. A 'system' approach and mathematical modeling in biological sciences are not new in itself, as they were used in biochemistry, physiology and genetics long before the name systems biology was coined. However, the present combination of mass biological data and of computational and modeling tools is unprecedented and truly represents a major paradigm shift in biology. Significant advances have been made using systems biology approaches, especially in the field of bacterial and eukaryotic cells and in human medicine. Similarly, progress is being made with 'system approaches' in animal sciences, providing exciting opportunities to predict and modulate animal traits.     

Potentials of single‐cell biology in identification and validation of disease biomarkers

Single‐cell biology is considered a new approach to identify and validate disease‐specific biomarkers. However, the concern raised by clinicians is how to apply single‐cell measurements for clinical practice, translate the message of single‐cell systems biology into clinical phenotype or explain alterations of single‐cell gene sequencing and function in patient response to therapies. This study is to address the importance and necessity of single‐cell gene sequencing in the identification and development of disease‐specific biomarkers, the definition and significance of single‐cell biology and single‐cell systems biology in the understanding of single‐cell full picture, the development and establishment of whole‐cell models in the validation of targeted biological function and the figure and meaning of single‐molecule imaging in single cell to trace intra‐single‐cell molecule expression, signal, interaction and location. We headline the important role of single‐cell biology in the discovery and development of disease‐specific biomarkers with a special emphasis on understanding single‐cell biological functions, e.g. mechanical phenotypes, single‐cell biology, heterogeneity and organization of genome function. We have reason to believe that such multi‐dimensional, multi‐layer, multi‐crossing and stereoscopic single‐cell biology definitely benefits the discovery and development of disease‐specific biomarkers.     

Molecular approaches to malaria: MAM 2004 and beyond

This special issue of Trends in Parasitology comprises a collection of timely reviews arising from the 2nd Molecular Approaches to Malaria meeting held 1-5 February 2004 in Lorne, Australia, four years after the successful inaugural meeting. As the name suggests, Molecular Approaches to Malaria focused on the latest molecular developments in malaria research, and their biological and clinical implications. By no means is this special issue intended to represent a comprehensive recapitulation of all of the presentations at the meeting. Rather, the articles address, in more general terms, recent advances on broader themes that were prominent at Molecular Approaches to Malaria meeting 2004.     

Biomarkers in molecular epidemiology studies for health risk prediction

The field of molecular epidemiology is very promising, as sophisticated techniques are being developed to address etiology, genetic susceptibility and mechanisms for induction of disease. The use of biomarkers plays a key role in these investigations because the information can be used to predict the development of disease and to implement disease prevention programs. However, as emphasized by Frederica P. Perera, the field is strewn with studies either that failed to use validated biomarkers or whose designs did not adequately consider the biology of the endpoints, and the availability of validated biomarkers of health risk is still limited. In this review, we have briefly described the usefulness of certain biomarkers for the documentation of exposure and early biological effects, with special concern for the prediction of cancer. An emphasis is placed on understanding the biological and health significance of biomarkers. By building reliable biomarker databases, a promising future is the integration of information from the genome programs to expand the scientific frontiers on etiology, health risk prediction and prevention of environmental disease.     

Fluorescence microscopy today

Fluorescence microscopy has undergone a renaissance in the last decade. The introduction of green fluorescent protein (GFP) and two-photon microscopy has allowed systematic imaging studies of protein localization in living cells and of the structure and function of living tissues. The impact of these and other new imaging methods in biophysics, neuroscience, and developmental and cell biology has been remarkable. Further advances in fluorophore design, molecular biological tools and nonlinear and hyper-resolution microscopies are poised to profoundly transform many fields of biological research.     

Imaging the living plant cell: From probes to quantification

At the center of cell biology is our ability to image the cell and its various components, either in isolation or within an organism. Given its importance, biological imaging has emerged as a field of its own, which is inherently highly interdisciplinary. Indeed, biologists rely on physicists and engineers to build new microscopes and imaging techniques, chemists to develop better imaging probes, and mathematicians and computer scientists for image analysis and quantification. Live imaging collectively involves all the techniques aimed at imaging live samples. It is a rapidly evolving field, with countless new techniques, probes, and dyes being continuously developed. Some of these new methods or reagents are readily amenable to image plant samples, while others are not and require specific modifications for the plant field. Here, we review some recent advances in live imaging of plant cells. In particular, we discuss the solutions that plant biologists use to live image membrane-bound organelles, cytoskeleton components, hormones, and the mechanical properties of cells or tissues. We not only consider the imaging techniques per se, but also how the construction of new fluorescent probes and analysis pipelines are driving the field of plant cell biology.

Specific examples are used to illustrate some of the challenges of live cell imaging, from designing genetically encoded probes to choosing a pipeline for image analysis and quantification.     

Reproductive/urogenital organ development and molecular genetic cascades: glamorous developmental processes of bodies

At the beginning of the 21st century, developmental biologists together with medical researchers in a wide range of fields are witnessing rapid progress in molecular developmental biology. For example, conditional gene knockout systems are being designed to tackle questions about organogenesis and body plan formation in experimental mouse models and experimental designs include several compound mutant analyses and genome modification strategies. On the other hand, several fields remain relatively unexplored. Molecular mechanisms of sex differentiation are one of the unexplored huge area. Unanswered questions include the molecular genetic cascade of gonad formation, reproductive organ formation, uterus, external genitalia and mammary gland formation, and also the molecular mechanisms of signal transduction, and gene regulation by nuclear hormone receptors. This special thematic review series entitled, "Reproductive/urogenital organ development and molecular genetic cascades: glamorous developmental processes of bodies," covers such a wide range of topics. For this special issue, I have asked active researchers to contribute reviews of these topics which I believe will be useful not only for molecular developmental biologists, but also for researchers in biochemistry and cell biology. It will be my great pleasure if this special thematic issue encourages scientists to study this exciting research field.     

The role of secondary ion mass spectrometry (SIMS) in biological microanalysis: technique comparisons and prospects.

The virtues and limitations of SIMS ion microscopy are compared with other spectroscopic techniques applicable to biological microanalysis, with a special emphasis on techniques for elemental localization in biological tissue (electron, X-ray, laser, nuclear, ion microprobes). Principal advantages of SIMS include high detection sensitivity, high depth resolution, isotope specificity, and possibilities for three-dimensional imaging. Current limitations, especially in comparison to X-ray microanalysis, center on lateral spatial resolution and quantification. Recent SIMS instrumentation advances involving field emission liquid metal ion sources and laser post-ionization will help to minimize these limitations in the future. The molecular surface analysis capabilities of static SIMS, especially with the new developments in commercial time-of-flight spectrometers, are promising for application to biomimetic, biomaterials, and biological tissue or cell surfaces. However, the direct microchemical imaging of biomolecules in tissue samples using SIMS will be hindered by limited concentrations, small analytical volumes, and the inefficiencies of converting surface molecules to structurally significant gas phase ions. Indirect detection using elemental or isotopically tagged molecules, however, shows considerable promise for molecular imaging studies using SIMS ion microscopy.     

Cell biology, chemogenomics and chemoproteomics

The scientific techniques used in molecular biological research and drug discovery have changed dramatically over the past 10 years due to the influence of genomics, proteomics and bioinformatics. Furthermore, genomics and functional genomics are now merging into a new scientific approach called chemogenomics. Advancements in the study of molecular cell biology are dependent upon "omics" researchers realizing the importance of and using the experimental tools currently available to cell biologists. For example, novel microscopic techniques utilizing advanced computer imaging allow for the examination of live specimens in a fourth dimension, viz., time. Yet, molecular biologists have not taken full advantage of these and other traditional and novel cell biology techniques for the further advancement of genomic and proteomic-oriented research. The application of traditional and novel cellular biological techniques will enhance the science of genomics. The authors hypothesize that a stronger interdisciplinary approach must be taken between cell biology (and its closely related fields) and genomics, proteomics and bio-chemoinformatics. Since there is a lot of confusion regarding many of the "omics" definitions, this article also clarifies some of the basic terminology used in genomics, and related fields. It also reviews the current status and future potential of chemogenomics and its relationship to cell biology. The authors also discuss and expand upon the differences between chemogenomics and the relatively new term--chemoproteomics. We conclude that the advances in cell biology methods and approaches and their adoption by "omics" researchers will allow scientists to maximize our knowledge about life.