Genome data: what do we learn?

Genome sequence information has continued to accumulate at a spectacular pace during the past year. Details of the sequence and gene content of human chromosome 22 were published. The sequencing and annotation of the first two Arabidopsis thaliana chromosomes was completed. The sequence of chromosome 3 from Plasmodium falciparum, the second sequenced malaria chromosome, was reported, as was that of chromosome 1 from Leishmania major. The complete genomic sequences of five microbes were reported. Approaches to using data from completely sequenced microbial genomes in phylogenetic studies are being explored, as is the application of microarrays to whole genome expression analysis.     

Phylloquinone, what can we learn from plants?

The plant plasma membrane contains redox proteins able to mediate a trans-membrane electron flow. This electron flow might be responsible for the generation of the active oxygen species observed as a reaction to pathogen attack or stress. Vitamin K1 could be identified as a possible lipid soluble electron carrier in plant plasma membrane preparations. Such a function would be analogous to coenzyme Q in animal plasma membranes. What we are going to outline in this contribution is a concept of how the electron transport system of the plant plasma membrane could interact with quinones, thus contributing to the metabolism of free radicals in plants.     

Invertebrate learning: what can't a worm learn?

The nematode worm Caenorhabditis elegans can learn and remember the stimuli it encounters, the environment it is in, and its own physiological state. Analyses of mutations in C. elegans that affect different aspects of experience are beginning to address the nature of learning.     

Archaea: what can we learn from their sequences?

Gene-by-gene and traditional biochemical approaches continue to reveal surprising molecular features in the archaeal domain. In addition, the complete sequencing of several archaeal genomes has further confirmed the phenotypic coherence of these micro-organisms at the molecular level. Nevertheless, the phylogeny of Archaea and the nature of the last universal common ancestor are still matters for debate.     

Salt stress tolerance; what do we learn from halophytes?

Abiotic environmental stresses can give rise to morphological, biochemical and molecular changes that negatively affect plant growth and productivity. Among these stresses, soil salinity is the major threat. To deal and control effects of high salinity on plants, it is important to understand their responses to salt stress that disturbs the homeostatic equilibrium at cellular and molecular levels. In this regard halophytes (salt tolerant plants) can provide superior models for the study of salt stress defense parameters compared to salt sensitive species (glycophytes). Halophytes use highly developed, complex systems to tolerate salinity by maintaining a low cytosolic Na⁺/K⁺ ratio, sequestration of Na⁺ into vacuoles that then provides the osmotic potential sustaining water influx. Under low intensity stress conditions that moderately and/or transiently affect ion imbalance, the set of responses all plants initiate will be mostly to engage measures that assure ion balance. High salinity, especially over a prolonged time period, will challenge plant survival, which then requires different strategies that employ a variety of mechanisms. Plasticity and connectivity of these diverse mechanisms is engrained in species- and family-specific evolutionary history and their genetic complexity. Highlighting differences in the genetic and biochemical makeup between glycophytes and halophytes allows for comparisons between their approaches towards high salinity. This review provides a brief overview about different strategies and mechanism used by plants to avoid or confine adverse effects of high salinity.     

Bats and moths: what is there left to learn?

Abstract.  Over 14 families of moths have ears that are adapted to detect the ultrasonic echolocation calls of bats. On hearing a bat, these moths respond with an escape response that reduces their chances of being caught. As an evolutionary response, bats may then have evolved behavioural strategies or changes in call design to overcome the moth's hearing. The nature of this interaction is reviewed. In particular, the role of the echolocation calls of bats in the shaping of the structure, neurophysiology and behavioural responses of moths is discussed. Unresolved issues, such as the structural complexity of the moth's auditory system, the nature of temporal integration and the role of the non-auditory B cell, are described. Issues in which the interactions between bats and moths may be of more general interest to biologists, such as noise filtering within the central nervous system, protean behaviours and coevolution between predator and prey, are also discussed. The interaction between bats and moths has much to interest general biologists, and may provide a useful model in understanding the neurophysiological basis of behaviour, including protean escape behaviours. The validity of the term coevolution as applied to this system is discussed, as there is no doubt that the auditory system of moths is a response to the echolocation calls of bats, although the evolutionary response of bats to moths is more ambiguous.     

Modeling memory: what do we learn from attractor neural networks?

In this paper we summarize some of the main contributions of models of recurrent neural networks with associative memory properties. We compare the behavior of these attractor neural networks with empirical data from both physiology and psychology. This type of network could be used in models with more complex functions.     

Malaria in pregnancy and the endemicity spectrum: what can we learn?

The increased susceptibility of pregnant women to malaria infection has long been recognized, but the magnitude of the disease burden in this particular group, together with the pathophysiology of maternal malaria and the specific difficulties in treatment, have only recently been the focus of research. Most research on maternal malaria has derived from sub-Saharan Africa where transmission is high, whereas most of the studies on the treatment of malaria and the effect of non-falciparum species has been conducted in low-transmission areas of Asia. In this paper, we attempt to improve our understanding of the disease and its mechanisms from observed differences and similarities between contrasting areas of transmission, and to identify priorities for future research.     

The medical therapy of prostatic symptoms study: what will we learn?

Until recently, benign prostatic hyperplasia (BPH) was thought of as a relatively uncomplicated disease process resulting from age-related enlargement of the prostate gland, which was thought to cause all of the symptoms associated with the disease. Prostatectomy was considered the state-of-the art treatment of BPH. Advances in our understanding of the pathogenesis of BPH and the relationship among clinical signs and symptoms has allowed for the development of pharmacologic therapies for this disorder, namely, selective alpha-blockers and 5-alpha-reductase inhibitors. These 2 classes of drugs have been demonstrated to be safe and effective for the treatment of BPH. Evidence supports different mechanisms of action, suggesting that, when used in combination, these therapies may act synergistically. The Medical Therapy of Prostatic Symptoms study was designed, in part, to test this hypothesis. Initial results of the trial are presented in this article.     

Plant‐insect interactions: what can we learn from plant lectins?

Many plant lectins have high anti‐insect potential. Although the effects of most lectins are only moderately influencing development or population growth of the insect, some lectins have strong insecticidal properties. In addition, some studies report a deterrent activity towards feeding and oviposition behavior. Transmission of plant lectins to the next trophic level has been investigated for several tritrophic interactions. Effects of lectins with different sugar specificities can vary substantially with the insect species under investigation and with the experimental setup. Lectin binding in the insect is an essential step in exerting a toxic effect. Attempts have been made to study the interactions of lectins in several insect tissues and to identify lectin‐binding receptors. Ingested lectins generally bind to parts of the insect gut. Furthermore, some lectins such as the Galanthus nivalus agglutinin (GNA) cross the gut epithelium into the hemolymph and other tissues. Recently, several candidate lectin‐binding receptors have been isolated from midgut extracts. To date little is known about the exact mechanism for insecticidal activity of plant lectins. However, insect glycobiology is an emerging research field and the recent technological advances in the analysis of lectin carbohydrate specificities and insect glycobiology will certainly lead to new insights in the interactions between plant lectins and insects, and to a better understanding of the molecular mechanisms involved. © 2010 Wiley Periodicals, Inc.     

Spatial pattern in Antarctica: what can we learn from Antarctic bacterial isolates?

A range of small- to moderate-scale studies of patterns in bacterial biodiversity have been conducted in Antarctica over the last two decades, most suggesting strong correlations between the described bacterial communities and elements of local environmental heterogeneity. However, very few of these studies have advanced interpretations in terms of spatially associated patterns, despite increasing evidence of patterns in bacterial biogeography globally. This is likely to be a consequence of restricted sampling coverage, with most studies to date focusing only on a few localities within a specific Antarctic region. Clearly, there is now a need for synthesis over a much larger spatial to consolidate the available data. In this study, we collated Antarctic bacterial culture identities based on the 16S rRNA gene information available in the literature and the GenBank database (n > 2,000 sequences). In contrast to some recent evidence for a distinct Antarctic microbiome, our phylogenetic comparisons show that a majority (~75 %) of Antarctic bacterial isolates were highly similar (≥99 % sequence similarity) to those retrieved from tropical and temperate regions, suggesting widespread distribution of eurythermal mesophiles in Antarctic environments. However, across different Antarctic regions, the dominant bacterial genera exhibit some spatially distinct diversity patterns analogous to those recently proposed for Antarctic terrestrial macroorganisms. Taken together, our results highlight the threat of cross-regional homogenisation in Antarctic biodiversity, and the imperative to include microbiota within the framework of biosecurity measures for Antarctica.     

Mammalian skeletogenesis and extracellular matrix: what can we learn from knockout mice?

Formation of the vertebrate skeleton and the proper functions of bony and cartilaginous elements are determined by extracellular, cell surface and intracellular molecules. Genetic and biochemical analyses of human heritable skeletal disorders as well as the generation of knockout mice provide useful tools to identify the key players of mammalian skeletogenesis. This review summarises our recent work with transgenic animals carrying ablated genes for cartilage extracellular matrix proteins. Some of these mice exhibit a lethal phenotype associated with severe skeletal defects (type II collagen-null, perlecan-null), whereas others show mild (type IX collagen-null) or no skeletal abnormalities (matrilin-1-null, fibromodulin-null, tenascin-C-null). The appropriate human genetic disorders are discussed and contrasted with the knockout mice phenotypes.     

Epidermal stem cell fate: what can we learn from embryonic stem cells?

Because of its constant renewal and high propensity for repair, the epidermis is, together with the gut and the hematopoietic system, a tissue of choice to explore stem cell biology. Previous research over many years has revealed the complexity of the epidermis: the heterogeneity of the stem cell compartment, with its rare, slowly cycling, multipotent, hair-follicle, “bulge” stem cells and the more restricted interfollicular, follicle-matrix, and sebaceous-gland stem cells, which in turn generate the large pool of transit-amplifying progeny. Stem cell activity has been used for some considerable time to repair skin injuries, but ex-vivo keratinocyte amplification has its limitations, and grafted skin homeostasis is not totally satisfactory. Human embryonic stem cells raise the hope that the understanding of the developmental steps leading to the generation of epidermal stem cells and the characterization of the key signaling pathways involved in skin morphogenesis (such as p63) will be translated into therapeutic benefit. Our recent results suggest the feasibility not only of identifying but also of amplifying human ES cells, early ectodermal progenitors with an intact multipotent potential that might improve the quality and functionality of grafts, provided that preclinical in vivo studies confirm our expectations from in vitro analysis. The work described here was supported by funds from the Sixth EEC Framework Program under the EPISTEM project, l’Agence Nationale pour la Recherche (ANR projets blancs), INSERM, and the Institut National Contre le Cancer (INCa).     

Lessons from Immune 1-3: what did we learn and what do we need to do in the future?

Sprague-Dawley rats were subjected to three 8-to-10 day space flights on the Space Shuttle. Housed in NASA's Animal Enclosure Modules, rats were flown to test the hypotheses that therapy with pegylated interleukin-2 or insulin-like growth factor-1 would ameliorate some of the effects of space flight on the immune system. As part of these experiments, we measured body and organ weights, blood cell differentials, plasma corticosterone, macrophage colony forming units, lymphocyte mitogenic, super-antigenic and interferon-gamma responses, bone marrow cell and peritoneal macrophage cytokine secretion and bone strength and mass. This paper compares some of the immunophysiological parameters of the control animals used in the Immune1-3 flight series and presents data from an animal infection model for use during space flight.     

Telomeres and race: what can we learn about human biology from health differentials?

The advent of molecular technology that can be applied across large population samples has added – rather than reduced – complexity in the analysis of the intertwined effects of social history and heritable factors on health outcomes. The report by Hunt et al . in this issue of Aging Cell provides an example of the promises and dilemmas associated with this increased complexity.