Biological Level (biological + level)

Distribution by Scientific Domains


Selected Abstracts


Alcohol and violence and the possible role of serotonin

CRIMINAL BEHAVIOUR AND MENTAL HEALTH, Issue 1 2003
Abdulla A.-B.
Background There is undisputed evidence linking alcohol consumption and violence and other forms of aggressive behaviour, and also linking aggression with dysfunction of the brain indolylamine serotonin (5-hydroxytryptamine or 5-HT). Alcohol consumption also causes major disturbances in the metabolism of brain serotonin. In particular, acute alcohol intake depletes brain serotonin levels in normal (non-alcohol-dependent) subjects. On the basis of the above statements, it is suggested that, at the biological level, alcohol may induce aggressive behaviour in susceptible individuals, at least in part, by inducing a strong depletion of brain serotonin levels. Aims In this article, evidence supporting these interrelationships and interactions will be summarized and discussed, the alcohol,serotonin,aggression hypothesis will be reiterated, and potential intervention strategies will be proposed. Copyright © 2003 Whurr Publishers Ltd. [source]


Epigenetic influence of social experiences across the lifespan

DEVELOPMENTAL PSYCHOBIOLOGY, Issue 4 2010
Frances A. Champagne
Abstract The critical role of social interactions in driving phenotypic variation has long been inferred from the association between early social deprivation and adverse neurodevelopmental outcomes. Recent evidence has implicated molecular pathways involved in the regulation of gene expression as one possible route through which these long-term outcomes are achieved. These epigenetic effects, though not exclusive to social experiences, may be a mechanism through which the quality of the social environment becomes embedded at a biological level. Moreover, there is increasing evidence for the transgenerational impact of these early experiences mediated through changes in social and reproductive behavior exhibited in adulthood. In this review, recent studies which highlight the epigenetic effects of parent,offspring, peer and adult social interactions both with and across generations will be discussed and the implications of this research for understanding the developmental origins of individual differences in brain and behavior will be explored. © 2010 Wiley Periodicals, Inc. Dev Psychobiol 52: 299,311, 2010. [source]


Adverse outcome pathways: A conceptual framework to support ecotoxicology research and risk assessment

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 3 2010
Gerald T. Ankley
Abstract Ecological risk assessors face increasing demands to assess more chemicals, with greater speed and accuracy, and to do so using fewer resources and experimental animals. New approaches in biological and computational sciences may be able to generate mechanistic information that could help in meeting these challenges. However, to use mechanistic data to support chemical assessments, there is a need for effective translation of this information into endpoints meaningful to ecological risk,effects on survival, development, and reproduction in individual organisms and, by extension, impacts on populations. Here we discuss a framework designed for this purpose, the adverse outcome pathway (AOP). An AOP is a conceptual construct that portrays existing knowledge concerning the linkage between a direct molecular initiating event and an adverse outcome at a biological level of organization relevant to risk assessment. The practical utility of AOPs for ecological risk assessment of chemicals is illustrated using five case examples. The examples demonstrate how the AOP concept can focus toxicity testing in terms of species and endpoint selection, enhance across-chemical extrapolation, and support prediction of mixture effects. The examples also show how AOPs facilitate use of molecular or biochemical endpoints (sometimes referred to as biomarkers) for forecasting chemical impacts on individuals and populations. In the concluding sections of the paper, we discuss how AOPs can help to guide research that supports chemical risk assessments and advocate for the incorporation of this approach into a broader systems biology framework. Environ. Toxicol. Chem. 2010;29:730,741. © 2009 SETAC [source]


Research Review: Crossing syndrome boundaries in the search for brain endophenotypes

THE JOURNAL OF CHILD PSYCHOLOGY AND PSYCHIATRY AND ALLIED DISCIPLINES, Issue 6 2009
Yonata Levy
The inherent imprecision of behavioral phenotyping is the single most important factor contributing to the failure to discover the biological factors that are involved in psychiatric and neurodevelopmental disorders (e.g., Bearden & Freimer, 2006). In this review article we argue that in addition to an appreciation of the inherent complexity at the biological level, a rather urgent task facing behavioral scientists involves a reconsideration of the role that clinical syndromes play in psychological theorizing, as well as in research into the biological basis of cognition and personality. Syndrome heterogeneity, cross-syndrome similarities and syndrome comorbidities question the relevance of syndromes to biological research. It is suggested that the search for brain endophenotypes, intermediate between genes and behavior, should be based on cross-syndrome, trait classification. Cohort selection should rest on behavioral homogeneity, enabling, when necessary, syndrome heterogeneity. [source]


The genome-centric concept: resynthesis of evolutionary theory

BIOESSAYS, Issue 5 2009
Henry H. Q. Heng
Abstract Modern biology has been heavily influenced by the gene-centric concept. Paradoxically, this very concept , on which bioresearch is based , is challenged by the success of gene-based research in terms of explaining evolutionary theory. To overcome this major roadblock, it is essential to establish new theories, to not only solve the key puzzles presented by the gene-centric concept, but also to provide a conceptual framework that allows the field to grow. This paper discusses a number of paradoxes and illustrates how they can be addressed by the genome-centric concept in order to further resynthesize evolutionary theory. In particular, methodological breakthroughs that analyze genome evolution are discussed. The multiple interactions among different levels of a complex system provide the key to understanding the relationship between self-organization and natural selection. Darwinian natural selection applies to the biological level due to its unique genetic and heterogeneous features, but does not simply or directly apply to either the lower non-living level or higher intellectual society level. At the complex bio-system level, the genome context (the entire package of genes and their genomic physical relationship or genomic topology), not the individual genes, defines the system and serves as the principle selection platform for evolution. [source]


Subcellular cadmium distribution, accumulation, and toxicity in a predatory gastropod, Thais clavigera, fed different prey

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 1 2006
Ma-Shan Cheung
Abstract Bioaccumulation and toxicity of Cd were investigated in a marine predatory whelk, Thais clavigera, after being fed with the rock oyster, Saccostrea cucullata, or the herbivorous snail, Monodonta labio, for up to four weeks. The oysters and snails had different subcellular Cd distributions and concentrations in their bodies given their different metal-handling strategies and were exposed to dissolved Cd for two weeks before being fed to the whelks. After four weeks of dietary exposure, the Cd body concentrations in T. clavigera increased from 3.1 ,g/g to between 22.9 and 41.8 ,g/g and to between 22.7 and 24.1 ,g/g when they were fed with oyster and snail prey, respectively. An increasing proportion of Cd was found to be distributed in the metallothionein (MT)-like proteins and organelle fractions, whereas the relative distribution in the metal-rich granules fraction decreased when the whelks were fed Cd-exposed prey. At the highest Cd dosage, more Cd was distributed in the pool of metal-rich granules when the whelks were fed the oysters than when they were fed the snails. Among all the biomarkers measured (MT induction, condition index, lipid peroxidation, and total energy reserve including carbohydrate, lipid, and protein), only MT showed a significant difference from the control treatments, and MT was the most sensitive biomarker for dietary Cd exposure. No toxicity was found in the whelks fed different Cd-exposed prey as revealed by various biomarkers at the different biological levels. Our results imply that metal fractionation in prey can alter the subsequent subcellular metal distribution in predators and that dietary Cd toxicity to the whelks was low, even when the accumulated Cd body concentrations were high. [source]


The carrying capacity of ecosystems

GLOBAL ECOLOGY, Issue 6 2004
Pablo Del Monte-Luna
ABSTRACT We analyse the concept of carrying capacity (CC), from populations to the biosphere, and offer a definition suitable for any level. For communities and ecosystems, the CC evokes density-dependence assumptions analogous to those of population dynamics. At the biosphere level, human CC is uncertain and dynamic, leading to apprehensive rather than practical conclusions. The term CC is widely used among ecological disciplines but remains vague and elusive. We propose the following definition: the CC is ,the limit of growth or development of each and all hierarchical levels of biological integration, beginning with the population, and shaped by processes and interdependent relationships between finite resources and the consumers of those resources'. The restrictions of the concept relate to the hierarchical approach. Emergent properties arise at each level, and environmental heterogeneity restrains the measurement and application of the CC. Because the CC entails a myriad of interrelated, ever-changing biotic and abiotic factors, it must not be assumed constant, if we are to derive more effective and realistic management schemes. At the ecosystem level, stability and resilience are dynamic components of the CC. Historical processes that help shape global biodiversity (e.g. continental drift, glaciations) are likely drivers of large-scale changes in the earth's CC. Finally, world population growth and consumption of resources by humanity will necessitate modifications to the paradigm of sustainable development, and demand a clear and fundamental understanding of how CC operates across all biological levels. [source]


Use of the ecological information system SynBioSys for the analysis of large datasets

JOURNAL OF VEGETATION SCIENCE, Issue 4 2007
Joop H.J. Schaminée
Abstract The rapid developments in computer techniques and the availability of large datasets open new perspectives for vegetation analysis aiming at better understanding of the ecology and functioning of ecosystems and underlying mechanisms. Information systems prove to be helpful tools in this new field. Such information systems may integrate different biological levels, viz. species, community and landscape. They incorporate a GIS platform for the visualization of the various layers of information, enabling the analysis of patterns and processes which relate the individual levels. An example of a newly developed information system is SynBioSys Europe, an initiative of the European Vegetation Survey (EVS). For the individual levels of the system, specific sources are available, notably national and regional Turboveg databases for the community level and data from the recently published European Map of Natural Vegetation for the landscape level. The structure of the system and its underlying databases allow user-defined queries. With regard to its application, such information systems may play a vital role in European nature planning, such as the implementation the EU-program Natura 2000. To illustrate the scope and perspectives of the program, some examples from The Netherlands are presented. They are dealing with long-term changes in grassland ecosystems, including shifts in distribution, floristic composition, and ecological indicator values. [source]


An unusual case of vascular hypogonadism treated with clomiphene citrate and testosterone replacement

ANDROLOGIA, Issue 1 2009
R. S. Tan
Summary Many male patients are discovered on screening to suffer from hypogonadism and age related hypogonadism is being increasingly recognized. However, secondary causes of hypogonadism should not be overlooked, especially in patients who may have concomitant morbidity as highlighted in this case. Our patient with vascular hypogonadism was treated with testosterone and clomiphene citrate in cycles; with a hope of improving not only androgen levels but overall pituitary function as there were co-existing endocrine pathologies of albeit primary hypothyroidism and low IGF-1 levels. Treatment with exogenous testosterone is fairly well established; but there is also increasing evidence of the effectiveness and short-term safety of clomiphene citrate in restoring not only biological levels but functional states in males as well. As such, we report an unusual case of a patient seen at our Men's Health & Andrology clinic in which both the cause of some otherwise unremarkable symptoms and the treatment, using a combination of clomiphene citrate and testosterone, were remarkable. [source]