Redox‐Regulation. Ein Netzwerk zur flexiblen Adaptation von Stoffwechsel und Entwicklung bei Pflanzen

Plants are dependent upon environmental factors for their photoautotrophic growth; but they are frequently exposed to suboptimal conditions due to their sessile life form. They are capable to adapt to a variety of conditions, since even plants of the same genotype exhibit a phenotypical plasticity by change of their “reaction norm”. All the informations are integrated, transduced via a highly flexible network, and realized. The reactions take place at all levels of regulation and comprise fast biophysical and biochemical processes (second and minute range) as well as slow reactions that are visible after hours (gene expression) or only after several days (growth). Redox processes are of importance in all these mechanisms. Deviation from redox‐homeostasis on the one hand serves as a signal, on the other hand it is necessary that larger imbalances are buffered to avoid damage.     

Psychiatric problems in the aged: a reconsideration

The numerically important mental disorders found in the senescent population are reviewed from the point of view of their relationship to the process of ageing. Only two direct relationships are seen: the acute confusional states due to the age-linked decline in stress resistance; and the neurotic reactions due to the diminished capacity for rapid and adequate adjustment to the more subtle but chronic sociopsychological changes the aged individual is so frequently exposed to in our society. The chronic dementing processes of the senium, senile and arteriosclerotic dementia, are more likely to occur at an advanced age, but apparently are not the final outcome of cerebral and/or cerebrovascular ageing, although the ageing process seems to favour their phenotypical manifestation. The functional psychoses may occur at an advanced age but are not directly related to the process of ageing.     

Gene-environment interactions and the affected-sib-pair designs

In genetic mapping of complex traits, the affected-sib-pair method (ASP) and the transmission disequilibrium test (TDT) are two methods of choice. The major appeal of both ASP and TDT is that they do not require the knowledge of mode of inheritance underlying the trait in question. The relative ease and economy for data collection also is the reason for their popularity. The basic idea of the ASP is to identify genes or chromosomal regions through identifying genetic similarity based on phenotypical similarity. TDT, on the other hand, detects susceptibility genes through detecting unusual transmission patterns in families. Since phenotypic similarity can also be caused by environmental similarity, we investigate how the presence of gene-environment interaction (GEI) affects the power of both methods. For a simple one-locus-one-risk-factor model, our results indicate that, in the presence of GEI, methods developed based on marginal penetrance functions (i.e. ignoring the risk factor) can give spurious results. The triangular restriction on allele-sharing probability may no longer be valid. If the environment effect is strong, using exposure-discordant affected sib pairs may have advantage over other designs. Above all, a genetic model involving both genetic and environmental factors behaves differently from a single-locus genetic model.     

Genetic dispersion analysis of the relationship of epilepsy to anomalies in brain bioelectrical activity

Estimation of genetic and environmental components of phenotypical dispersion of paroxysmal and nonparoxysmal EEG abnormalities in epilepsy (118 probands and 179 relatives) in two phenotypical model frames has been obtained. The alternative phenotypical model was shown to be more adequate than quasicontinual for EEG abnormalities, and the part of additive genetic component (GA) comprises 15.7% for paroxysmal abnormalities and 49.4% for nonparoxysmal type. In the component type "belonging to one generation" joint influence of genetic and environmental factors on the process of forming EEG abnormalities in ontogeny was observed. The GA value for "epilepsy manifestation" symptom equal to 72.9% in general selection of probands increases to 97.4% in the subgroup of patients with nonparoxysmal abnormalities and 67.4% in the subgroup of patients with paroxysmal EEG abnormalities. It has been suggested that paroxysmal EEG abnormalities reflect their own epileptic process, and as far as nonparoxysmal abnormalities are concerned, they present phenotypical manifestation of the genetic system of predisposition to epilepsy.     

Neutral biogeography of phylogenetically structured interaction networks

Little is known about how biogeographic processes affect the dynamics of species interactions in space and time, although it is widely accepted that they drive community assemblage. In functional interactions, such as pollination and seed dispersal, species that share common ancestry tend to retain a common number of interactions and interact with similar sets of species, a pattern more commonly observed for animals than plants. On the one hand, the most coherent explanation for the phylogenetic structure of pollination and seed dispersal networks is that species retain ecological traits over evolution, which would cause the conservation of interaction partners. On the other hand, fundamental processes of biodiversity, such as dispersal and evolutionary rates seem to have important roles shaping the observed phylogenetic structure of mutualistic networks, but no model has been created to study the effect of these processes in the phylogenetic structure of mutualistic interactions. Here, we developed a stochastic simulation model to study the evolution of two interacting groups of species, which evolve independently over the same geographical domain. In our model, individuals of the same interaction group share ecological traits, whereas individuals of different trophic groups are ecologically distinct. We show that even in the absence of ecological differences between individuals, and disregarding any conservation of phenotypical and phenological traits between species, the interplay of dispersal and speciation is still a major driver of complex phylogenetic structure of functional interactions, such as pollination and seed dispersal.     

Biological and functional analysis of statistically significant pathways deregulated in colon cancer by using gene expression profiles

Gene expression profiling offers a great opportunity for studying multi-factor diseases and for understanding the key role of genes in mechanisms which drive a normal cell to a cancer state. Single gene analysis is insufficient to describe the complex perturbations responsible for cancer onset, progression and invasion. A deeper understanding of the mechanisms of tumorigenesis can be reached focusing on deregulation of gene sets or pathways rather than on individual genes. We apply two known and statistically well founded methods for finding pathways and biological processes deregulated in pathological conditions by analyzing gene expression profiles. In particular, we measure the amount of deregulation and assess the statistical significance of predefined pathways belonging to a curated collection (Molecular Signature Database) in a colon cancer data set. We find that pathways strongly involved in different tumors are strictly connected with colon cancer. Moreover, our experimental results show that the study of complex diseases through pathway analysis is able to highlight genes weakly connected to the phenotype which may be difficult to detect by using classical univariate statistics. Our study shows the importance of using gene sets rather than single genes for understanding the main biological processes and pathways involved in colorectal cancer. Our analysis evidences that many of the genes involved in these pathways are strongly associated to colorectal tumorigenesis. In this new perspective, the focus shifts from finding differentially expressed genes to identifying biological processes, cellular functions and pathways perturbed in the phenotypic conditions by analyzing genes co-expressed in a given pathway as a whole, taking into account the possible interactions among them and, more importantly, the correlation of their expression with the phenotypical conditions.     

Comparison between marker-assisted selection and phenotypical selection in a set of Arabidopsis thaliana recombinant inbred lines

 Parents were selected from a well-characterised Arabidopsis recombinant inbred line (RIL) population based on (1) their phenotype for flowering time or (2) marker and QTL information that had been assessed previously. The F₂ offspring obtained from pairs of selected RILs was analysed for these traits, and the results obtained with these two methods of selection were compared. Selection based on marker and QTL information gave approximately the same result as selection based on phenotype. The relative high heritability of flowering time in Arabidopsis facilitated successful phenotypical selection. The difference in selection result that was anticipated to be in favour of the marker-assisted approach was therefore not observed. Received: 29 November 1997 / Accepted: 8 June 1998     

Target size analysis of neurotensin receptors

The neurotensin receptors from rat brain synaptosomal membranes differed in subunit structure from those in rat gastric fundus smooth muscle plasma membranes when studied following photoaffinity labelling or after exposure to cross-linking reagents. However, these two receptors were similar in their recognition properties. In this study we compared the target size of the two receptors by radiation inactivation and observed that the receptors in both tissues had similar target sizes (mean values 103,000 and 108,000 daltons). This suggests that the differences in size observed in biochemical studies may reflect changes occurring during the isolation procedures, or, on the other hand, there might be inherent difference in the subunit structure of these receptors.     

Necessity of chance: biological roulettes and biodiversity

Chance plays an important role in the dynamics of biodiversity. It is largely responsible for the spontaneous processes leading to biological diversification. The mechanisms behind chance belong to two categories: on the one hand, those outside of biological systems, and thus belonging to their environment, on the other hand, those endogenous to these systems. These last mechanisms are present at all levels of the hierarchical organization of the living world, from genes to ecosystems. We propose calling them 'biological roulettes'. Like roulettes in casinos, they could be deterministic processes functioning in chaotic domains and producing results that look as though they had been generated by random processes. The spontaneous appearance and natural selection of these roulettes have led to living systems potentially adapted to new environmental conditions not encountered before. They may even have permitted some of them to survive major upheavals. Moreover, palaeontological data show that the rate of biological diversification accelerates and that living systems become more and more complex over time. That may also increase their resilience. It can be also the consequence of the appearance and the selection of 'biological roulettes' and of chance they generate. They are at the same time products and engines of the evolution. Without them, life would have disappeared from the Earth a long time ago. Thus, they are of primary importance.     

Human infants and baboons show the same pattern of handedness for a communicative gesture

To test the role of gestures in the origin of language, we studied hand preferences for grasping or pointing to objects at several spatial positions in human infants and adult baboons. If the roots of language are indeed in gestural communication, we expect that human infants and baboons will present a comparable difference in their pattern of laterality according to task: both should be more right-hand/left-hemisphere specialized when communicating by pointing than when simply grasping objects. Our study is the first to test both human infants and baboons on the same communicative task. Our results show remarkable convergence in the distribution of the two species' hand biases on the two kinds of tasks: In both human infants and baboons, right-hand preference was significantly stronger for the communicative task than for grasping objects. Our findings support the hypothesis that left-lateralized language may be derived from a gestural communication system that was present in the common ancestor of baboons and humans.     

Multi-Level Semiosis: a Paradigm of Emergent Innovation

In this introductory article to the special issue on Multi-level semiosis we attempt to stage the background for qualifying the notion of “multi-levelness” when considering communication processes and semiosis in all life forms, i.e. from the cellular to the organismic level. While structures are organized hierarchically, communication processes require a kind of processual organization that may be better described as being heterarchical. Theoretically, the challenge arises in the temporal domain, that is, in the developmental and evolutionary dimension of dynamic semiotic processes. We discuss the importance of this fundamental difference in order to explain how levels, domains and orders of magnitude, on the one hand, and synchronic and diachronic processes, on the other, contribute to the overall organization of every living being. To account for such multi-level organization, semiotic freedom is assumed to be a scalar property that endows living systems at different levels and domains with the capacity to ponder selectively the overall structural coherence and functional compatibility of their heterarchical processing, which is increasingly less conditioned by the underlying molecular determinism.     

Interaction between the premotor processes of eye and hand movements: Possible mechanism underlying eye–hand coordination

Interaction between the execution process of eye movement and that of hand movement must be indispensable for eye–hand coordination. The present study investigated corticospinal excitability in the hand muscles during the premotor processes of eye and/or hand movement to elucidate interaction between these processes. Healthy humans performed a precued reaction task of eye and/or finger movement and motor-evoked potentials in the hand muscles were evoked in the reaction time. Leftward eye movement suppressed corticospinal excitability in the right abductor digiti minimi muscle only when little finger abduction was simultaneously executed. Corticospinal excitability in the first dorsal interosseous muscle was not suppressed by eye movement regardless of whether or not it was accompanied by finger movement. Suppression of corticospinal excitability in the hand muscles induced by eye movement in the premotor period depends on the direction of eye movement, the muscle tested, and the premotor process of the tested muscle. The suppression may reflect interaction between the motor process of eye movement and that of hand movement particularly active during eye–hand coordination tasks during which both processes proceed.     

On the role of sexual selection in ecological divergence: a test of body‐size assortative mating in the eastern newt Notophthalmus viridescens

Speciation processes initiated by divergent selection often fail to complete; yet, how sexual selection is involved in the progress of ecological speciation is rarely understood. Intraspecific body‐size variation affects mate preference and male–male competition, which can consequently lead to assortative mating based on body size. In the present study, we tested the importance of body size difference in the potential of assortative mating between the two eastern newt subspecies, larger Notophthalmus viridescens viridescens and smaller Notophthalmus viridescens dorsalis. Through differential expression of life‐cycle polyphenism, these two subspecies are adapted to contrasting environments, which has likely led to the subspecific body‐size difference. We found that males of both subspecies preferred larger females of N. v. viridescens as mates presumably because of the fecundity advantage of larger females. On the other hand, no evidence of female choice was found. Larger males of N. v. viridescens exhibited greater competitive ability and gained primary access to larger females of their own kind. However, smaller males were able to overcome their inferior competitive ability by interfering with larger males' spermatophore transfer and sneakily mating with larger females. Thus, the subspecific body‐size difference importantly affected sexual selection processes, resulting in nonrandom but not completely assortative mating patterns between the larger and smaller subspecies. Although life‐cycle polyphenism facilitates the intraspecific ecological divergence within N. v. viridescens sexual selection processes, namely smaller males' mate preference for larger females and sexual interference during spermatophore transfer, may be halting completion of the ecological speciation. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101 , 884–897.     

Computational analysis of the influence of the microenvironment on carcinogenesis

The tumour microenvironment is known to play an important role in determining the sequence of acquired phenotypic traits that characterise cancer evolution. A more precise understanding of this role could have a major influence in the understanding of cancer growth and development, and potentially in the optimisation of innovative anti-cancer treatments delivery. However, to lead such an analysis in the basis of traditional biological experiments and observations is almost utopian given the complexity of the underlying biological processes and the typical time scales involved. In this context, computer models constitute a complementary exploratory tool.In this paper we introduce a two-dimensional cellular automaton that models key cancer cell capabilities. The model has been especially designed to mimic the behaviour of a cancer colony growing in vitro and to analyse the effect of different environmental conditions on the sequence of acquisition of phenotypic traits. Our results indicate that microenvironmental factors such as the local concentration of oxygen or nutrients and cell overcrowding may determine the expansion of the tumour colony. The results also show that tumour cells evolve and that their phenotypes adapt to the microenvironment so that environmental stress determines the dominance of particular phenotypical traits.     

Mast cell granule composition and tissue location--a close correlation

This review provides a survey on mast cell heterogeneity, with aspects differing in humans and rodents or which are subject of conflicting evidence being discussed in greater detail. Mast cell subsets have been first defined in rats by their fixation and dye-binding properties, and detailed studies in humans and pigs reveal very similar observations. The dye-binding properties of rat mast cell subsets are causally related to the absence or presence of heparin in their granules. In humans, this relation has not been shown. Rodent mast cell subsets store different chymase-isoforms. In contrast, just a single chymase has been defined in humans, and mast cells are classified by the presence or relative absence of this chymase. Different investigators find quite different proportions of chymase-positive to chymase-negative mast cells. Tryptase(s) are found in most or every human mast cell, but in rodents, they have hitherto been essentially localised to mast cells in connective tissues. Human mast cell subsets may also be defined by their expression of receptors such as C5aR and possibly the beta-chemokine receptor CCR3; the CCR3 expression seems to be related to the human mast cell chymase expression. Ultrastructural studies are helpful to distinguish human mast cell subsets, and allow to distinguish between chronic and acute activation. The phenotypical characteristics may change in association with inflammation or other disease processes. Studies in humans and pigs show changed dye-binding and fixation properties of the granules. Experimental rodent infection models reveal similar changes of chymase isoform expression. Human lung mast cells have been reported to strongly upregulate their chymase content in pulmonary vascular disease. This line of evidence can explain some inconsistent information on mast cell heterogeneity and may help to understand the physiological role of mast cells.     

The Influence of Hand Preference on Grip Strength in Children and Adolescents; A Cross-Sectional Study of 2284 Children and Adolescents

Introduction

In adults the preferred hand is often considered to be around 10% stronger than the non-preferred hand. Whether the same is true for children and adolescents remains unclear. The objective of this study is therefore to determine whether there is a difference in grip strength between the preferred and non-preferred hand in developing children, to establish whether this difference is similar for children of a different gender or hand preference, and whether there is a difference in grip strength of the preferred hand of left-preferent (LP) and right-preferent (RP) children.

Design

Cross-sectional study.

Participants

Participants were recruited from schools in the northern provinces of the Netherlands. The study included healthy children and adolescents in the age range of 4–17 years.

Outcome Measures

Each child was allowed a total of four attempts using the JAMAR hand dynamometer, two attempts with each hand. All individual attempts were scored. Hand preference was determined by asking which hand was used to write, or in the case of 4- and 5-year-olds, which hand was used to draw a shape.

Results

The study population comprised 2284 children and adolescents. RP boys and girls scored significantly higher with their preferred hand, the difference amounting to 9.5 and 10.1% respectively. LP girls scored significantly higher with their preferred hand, but this difference was only 3.0%. For LP boys no significant difference was found in favor of either hand. LP children score higher with the non-preferred hand and tie scores on both hands more often than RP children.

Conclusion

The 10% rule of hand preference is applicable to RP children ranging in age between 4 and 17 years, but not to LP children. In contrast to LP boys, LP girls are generally significantly stronger with their preferred hand.     

Microalgae-mediated chemicals production and wastes removal

Biotechnology of microalgae has gained importance in recent years due to the development of new production and environmental technologies. Because their growth requires unexpensive substrates such as solar light and CO₂, microalgae can be used as cheap and effective biocatalysts to obtain high added-value compounds, from simple metabolites to complex molecules, i.e., chemicals, vitamins, carotenoids, pigments, or polysaccharides. During productive processes, the algal biomass formed may be used as a food source like proteins. On the other hand, microalgae can also be employed in contaminant bioelimination processes especially for nitrogen, phosphorus, or sulfur compounds. Particularly relevant is their use for heavy metal removal from wastewaters; upon enriching the biomass in the metal, they can be recovered, thereby providing economic advantages.

The use of immobilized microalgae in these processes is very adequate and offers significant advantages in bioreactors.     

Mathematical modelling of apoptosis and necrosis processes in in vitro cell culture

Mathematical models of apoptosis and necrosis in in vitro cultured cells for different ways of indication of phenotypical manifestations of these processes are proposed. The models make it possible to calculate the probability of apoptosis and necrosis programming of cells, to appraise and compare intensities of these processes using experimental data.     

Hand preference and tool use in wild chimpanzees

The hand preference of chimpanzees in their natural habitat was studied at Bossou, Republic of Guinea, West Africa. The quantitative difference in left/right hand use was small in food picking and carrying. In contrast, the chimpanzees employed either the right or left hand in nutcracking behavior using a pair of stones. All adults and many adolescents and juveniles utilized one hand exclusively for holding a hammer stone. Left hand preference was more prevalent among adults. However, when adolescents and juveniles were included, there was no significant bias in the ratio of left/right handers. Nut-cracking behavior requires long-term learning of the fine manipulation of stones and nuts by both hands. Each hand has a separate role, and the hands work together in nut cracking. The differential and complementary use of both hands may be a prime factor promoting exclusive hand preference in chimpanzees comparable to that of humans.     

Independent coding of movement duration in a repetitive non-visually guided movement

Temporal information is an embedded feature of our sensory and motor experiences. How is temporal information encoded in the brain? In the two-stage theory of timing, an explicit representation of timing is responsible for the movement initiation while movement duration is coded implicitly. We investigated the correlation of movement duration and amplitude in a repetitive one-dimensional non-visually guided movement to find out if temporal information could be coded independently from movement. Subjects were asked to learn the distance between two points by moving their hands repeatedly along the distance between two sticks, while they could not see their hands and hand path. After a training phase, a delay of either 2 or 20 s was imposed and the subjects were asked to reproduce the learned distance. There was no correlation between distance difference and time difference in either delay condition. In the 20 s delay experiment, in comparison to the 2 s delay experiment, there was a significant increase in distance reproduction error. However, there was no significant change in time differences in either of the experiments. In addition, the time difference between the training and test trials was independent from the direction of the distance difference (i.e., overshot, undershot, or accurate). In conclusion, time may be coded as an independent measure after the delay period, so it should be a kind of explicitly coded information.