Primer on medical genomics. Part IV: Expression proteomics

Proteomics, simply defined, is the study of proteomes. More completely, proteomics is defined as the study of all proteins, including their relative abundance, distribution, posttranslational modifications, functions, and interactions with other macromolecules, in a given cell or organism within a given environment and at a specific stage in the cell cycle. Proteins carry out the biological functions encoded by genes; hence, once the initial stage of genome sequencing and gene discovery is completed, a study of the proteome must be undertaken to address fundamental biological questions. The 3 broad areas are expression proteomics, which catalogues the relative abundance of proteins; cell-mapping or cellular proteomics, which delineates functional protein-protein interactions and organelle-specific protein distribution; and structural proteomics, which characterizes the 3-dimensional structure of proteins. With these approaches, proteins are studied on a global scale using a synergistic combination of powerful, high-throughput technologies, including 2-dimensional polyacrylamide gel electrophoresis, mass spectrometry, multidimensional liquid chromatography, and bioinformatics. Mass spectrometry, which provides highly accurate molecular mass measurements, has emerged as the analytical technology of choice for protein identification, characterization, and sequencing. This task has been made considerably easier with the availability of complete, nonredundant, and annotated genome sequence databases for many organisms. This article reviews the area of expression proteomics.

New molecular methods to study gene functions in Candida infections

Candida albicans has become a model system for human pathogenic fungi in clinical research, mainly due to the increasing number of Candida infections. Molecular techniques to study C. albicans virulence properties have been improved over the last few years, despite difficulties in genetic manipulation of this fungus. Some of the recent achievements from our own laboratory or from other groups are described in this article. The molecular analysis of the recently identified ATP-dependent transporter Mlt1 using the green fluorescent protein (GFP) as reporter for protein localization and the dominant MPAR gene as a selection marker for gene inactivation provides an example for the study of gene functions in C. albicans.

["Health is a Crossroad"--Nature and society, individual and community, in safeguarding public health]

Any person actively engaged in the sphere of Public Health who refers to "molecular medicine" is bound to arouse suspicion. Nevertheless, neither Public Health nor public health protection or the health sciences in general can afford to ignore medicine and biology. This fundamental fact is explored in a historical and subsequently in an anthropological context. The connections between molecular medicine and public health are discussed at length. Accordingly, health on an individual as well as on a social level is essentially bound to the knowledge of genetically determined dispositions. We may expect that this molecular-genetic reality will become as "true" in future as the hygienic-bacteriological reality has become "true" today. The medicalisation of all human realities will be continued by their "molecularisation". It is important to fundamentally understand the actual effects of this transformation, which is the subject of a wider public discussion. This is the only way to rationally estimate both the opportunities offered by molecular medicine and the involved risks. It is essential for a debate of this kind within public health care institutions that the public health movement addresses the current developments of molecular medicine in a critical but constructive manner. "Nature", and with it the medicine and biology of public health, is an essential aspect of protecting public health. This is the only way to clarify the sphere of activity of public health protection in general, to appreciate its dynamics and to develop adequate measures: "Health is a crossroad" according to Julio Frenk: "It is where biological and social factors, the individual and the community, and social economic policy all converge".

A molecular view on pluripotent stem cells

Pluripotent stem cells are undifferentiated cells that are capable of differentiating to all three embryonic germ layers and their differentiated derivatives. They are transiently found during embryogenesis, in preimplantation embryos and fetal gonads, or as established cell lines. These unique cell types are distinguished by their wide developmental potential and by their ability to be propagated in culture indefinitely, without loosing their undifferentiated phenotype. This short review intends to give a general overview on the pluripotent nature of embryo-derived stem cells with a focus on human embryonic stem cells.

Recent developments in molecular techniques for identification and monitoring of xenobiotic-degrading bacteria and their catabolic genes in bioremediation

The pollution of soil and water with xenobiotics is widespread in the environment and is creating major health problems. The utilization of microorganisms to clean up xenobiotics from a polluted environment represents a potential solution to such environmental problems. Recent developments in molecular-biology-based techniques have led to rapid and accurate strategies for monitoring, discovery and identification of novel bacteria and their catabolic genes involved in the degradation of xenobiotics. Application of these techniques to bioremediation has also improved our understanding of the composition, phylogeny, and physiology of metabolically active members of the microbial community in the environment. This review provides an overview of recent developments in molecular-biology-based techniques and their application in bioremediation of xenobiotics.

Introducing genetic psychophysiology

Genetic psychophysiology examines interindividual variation in psychophysiological traits using behavioral genetic and molecular genetic techniques. It aims to delineate the pathways that lead from genomic variation to individual differences in cognitive abilities, affect regulation, and mental and physical health. This editorial provides an introduction to the twin design and gene finding strategies using psychophysiological endophenotypes. It also gives a brief outline of the papers presented in this special issue on genetic psychophysiology. Its main objective, and the objective of the entire special issue, is to interest psychophysiologists in the enormous potential of research in this area and to foster the development of collaborative relationships between psychophysiologists and molecular and behavioral geneticists that are necessary to move research in this area forward.

New frontiers in molecular pediatric cardiology

Numerous advances in understanding the molecular basis of congenital heart disease have been published in the past year. Highlights are reviewed, focusing on two major topics: genetic syndromes and cardiac organogenesis. Genetic syndromes are discussed in the context of complementary data from targeted mutations in animals and genetic mapping studies in humans. These include the DiGeorge, Holt-Oram, Alagille, familial primary pulmonary hypertension, and Noonan syndromes. Novel concepts in cardiac organogenesis are discussed, including the existence and contribution of an anterior heart field to the developing cardiac outflow tract, novel cell-cell signaling involving migrating neural crest, the origins of the conduction system and initial embryonic heartbeat, and the possibility of a population of cardiac stem cells in the adult heart. The studies reviewed have potential clinical relevance in the near future and will be of interest to the clinician interested in congenital heart disease.

[Sharper diagnostic tool the future promise of laser-assisted microdissection]

The paper describes the use of laser-assisted microdissection to retrieve microscopically defined cell populations including single cells from tissue sections for subsequent analysis of genomic DNA and mRNA. A general background is given on the techniques available and requirements for PCR based on minute templates. Different pre-PCR approaches are briefly described and possibilities and limitations of using archival material compared to fresh frozen tissue are discussed. In the article we give one example on how we have used the PALM laser microscopy system in combination with a nested, multiplex PCR system to analyze single normal keratinocytes as well as tumor cells from a case of basal cell cancer. We found that p53 mutations are common in normal, chronically sun-exposed skin. Widespread yet common mutations in the p53 gene that were unrelated to immunoreactivity for the p53 antibody were found in tumor cells. In addition there were rare mutations in occasional tumor cells that apparently did not result in selective growth advantage. Perspectives for the future are presented and the potential of laser assisted microdissection is highlighted within the fields of cancer research, developmental studies as well as studies of inflammatory and degenerative diseases. The combination of a method that allows careful selection of defined cells with powerful micro array based techniques, provides a setting with potential to uncover pathogenic mechanisms for large variety of human diseases.

Molecular advances in genetic skin diseases

The genes for several genetic skin diseases have been identified in recent years. This development improves diagnostic capabilities and genetic counseling, and investigators can now turn to the molecular mechanisms involved in the pathogenesis of these diseases. The identification of the causative genes has led to the generation of mouse models for some genetic skin diseases. A study of the keratin 10 deficient mouse, a model for epidermolytic hyperkeratosis, and a mouse model for Bloom syndrome are reviewed in this article. Several studies also evaluate the relation between genotype and phenotype. In this article, the clinical findings and molecular advances in tuberous sclerosis complex, neurofibromatosis type 1, Bloom syndrome, epidermolytic hyperkeratosis, X-linked ichthyosis, Netherton syndrome, and Hermansky-Pudlak syndrome are reviewed.

The genetic basis for psychiatric illness in man

Following the influential genetic studies of Heston and Kety, there has been growing acceptance of the role of genes in determining behaviour. It is now recognized that most types of behaviour, from normal variations in traits such as personality to complex psychiatric disorders, are influenced not only by environmental factors but also by multiple genes. While twin and adoption studies have been vital in demonstrating the heritability of behaviour, the focus is now on the identification of the genes involved using the molecular genetic strategies linkage analysis and allelic association. This article will discuss techniques that have been used in psychiatric genetics, and how they have advanced our understanding of complex behaviour.