Root movements: Towards an understanding through attempts to model the processes involved

Roots have the ability to change the direction of their forward growth. Sometimes these directional changes are rapid, as in mutations, or they are slower, as in tropisms. The gravitational force is always present and roots have an efficient graviperception mechanism which enables them to initiate gravitropic movements. In trying to model and simulate the course of gravitropic root movements with a view to analyse the component processes, the following aspects of the plant's interaction with gravity have been considered: (1) The level of organization (organism, organ, cell) at which the movement process is expressed; (2) whether the gravity stimulation event is dynamic or static (i.e. whether or not physiologically significant displacements take place with respect to the gravity vector); (3) the sub-systems involved in movement and the processes which they regulate; (4) the mathematical characterization of the relevant sub-systems. A further allied topic is the nature of nutational movements and whether they are linked with gravitropic movements in some way. In considering how they can best be modelled, two types of nutational movements are proponed: stochastic nutation and circumnutation. Most, if not all, natural movements developed in response to static gravistimulation can be viewed as gravimorphisms. This applies at the levels of cell, organ and organism. However, when a system at any one of these levels experiences dynamic gravistimulation, because of its inherent homeostatic properties, it is induced to regenerate a state similar to that previously held. Thus, gravitropism is a regenerative gravimorphic process at the level of the organ.     

Towards the entire proteome of the model bacterium Bacillus subtilis by gel-based and gel-free approaches

With the emergence of mass spectrometry in protein science and the availability of complete genome sequences, proteomics has gone through a rapid development. The soil bacterium Bacillus subtilis, as one of the first DNA sequenced species, represents a model for Gram-positive bacteria and its proteome was extensively studied throughout the years. Having the final goal to elucidate how life really functions, one basic requirement is to know the entirety of cellular proteins. This review presents how far we have got in unraveling the proteome of B. subtilis. The application of gel-based and gel-free technologies, the analyses of different subcellular proteome fractions, and the pursuance of various physiological strategies resulted in a coverage of more than one-third of B. subtilis theoretical proteome.     

Towards the development of an ecophysiological Daphnia model to examine effects of toxicity and nutrition

Freshwater ecosystems are highly susceptible to mercury (Hg) deposition, which impacts biotic health and leads to serious consequences through biomagnification. The keystone zooplankter, Daphnia, exerts disproportionate effects on food web dynamics, displaying high sensitivity to natural stressors, and thus serving as an indicator of the broader impairments of aquatic ecosystems. Combined with metabolomics, the study of metabolites and their chemical processes, we have developed a model that attempts to elucidate the interactive effects of Hg toxicity and nutrition on phytoplankton-Daphnia relationships. Our model stipulates a physiological hierarchy, prioritizing different metabolic processes in the order of neurological functions, bioenergetics, osmoregulatory maintenance, waste management, and growth investments. Daphnia resilience is controlled by both food quantity and quality and each physiological process is modulated by the somatic levels of different metabolites. By enriching food with metabolites associated with neurological and energetic physiological pathways, effects of toxicity can be alleviated. Specifically, we demonstrate that metabolites associated with bioenergetics (carbohydrates, fats, proteins, and phosphorus) confer the greatest resilience to physiological changes induced by toxicity. Prey-predator dynamics can change significantly due to the detrimental impacts of toxicity on daphnid physiology and unfavourable nutritional stoichiometry. Under conditions of poor nutrition and extreme toxicity, our model demonstrates that daphnid populations may collapse and thus phytoplankton could escape intense grazing pressure. Founded upon the premise that response to stress can be more rapidly detected at the metabolic level, our study offers a new perspective to develop bioindicator systems and early warning signals for more efficient environmental monitoring.     

Marriage and the maintenance of ethnic group boundaries: the case of Mauritius

Research on how cognitive and cultural biases shape marital decisions in Mauritius suggests that ethnic endogamy will remain the norm and maintain ethnic group boundaries. Results of a pile sorting exercise of Mauritian university students intimates that preferences for ethnic endogamy are paramount and override class-based considerations. Thus, despite socio-economic stratification within each ethnic group, inter-ethnic marriage is not common. Results from in-depth interviews suggest that individuals and their parents prefer to marry within their ethnic group to ensure that their spouse will abide by ethnically-specific norms and conventions, increasing the chances of coordinating reciprocal exchanges within a marriage. The presence of some inter-ethnic marriage does not weaken the boundaries between groups because children of inter-ethnic marriages tend to take on the ethnic identity and corresponding cultural norms of a single parent as a strategy to better negotiate social relations, and to marry someone of that same ethnicity.     

Quantitative study of alpha-1-antitrypsin in an ethnic group of Ivory Coast: the Abrons]

A logarithmic-normal distribution of the concentrations of alpha1AT in 578 Abrons in Ivory Coast was found. A significant, negative logarithmic regression of alpha1AT rates according to age is demonstrated. alpha1AT rate = 0,376 (log age) + 3,003 The quantitative analysis by immunoprecipitation of Technicon only does not permit a definitive conclusion as to the presence of allele Z.     

Gene pool of Daghestan ethnic groups: Polymorphism of classical gene markers in the Darghin ethnic group

The work is part of a study of the gene pool for Daghestan ethnic groups. In total, 38 alleles and eight genotypes were studied at 14 loci (AB0, Rhesus, P, Lewis, Kell, PH, GC, C′3, TF, 6-PGD, GLO1, ESD, ACP, and PBM1) of immunogenetic and biochemical polymorphic gene systems. A high frequency of allele d of the Rhesus system was observed in all populations examined (0.399–0.474). Among the rare haplotypes of the Rhesus system, we observed CDE in the Degva population, Cde in the Sergokala and Degva populations, and cdE in the Sergokala and Vanashimakhi populations. The typical Caucasian ACP1 ^c allele of the ACP1 locus, which is rather uncommon, was observed at a relatively high frequency in three (Segokala, Vanashimakhi, and Gubden) of the four local populations under study. In the Lewis system, a high frequency of the Le(a+b+) phenotype, which is characteristic of early childhood, was detected in the adult populations of Sergokala and Degva. The rare PGM ₁ ^V allele of the phosphoglucomutase 1 system (PGM1) was additionally observed in the Sergokala population. Statistical analysis identified 19 cases where the observed phenotype frequencies significantly differed from the frequencies expected from the Hardy-Weinberg equilibrium.     

Gene pool of Dagestan ethnic groups: polymorphism of classical gene markers in the Darghin ethnic group

The work is part of a study of the gene pool for Daghestan ethnic groups. In total, 38 alleles and eight genotypes were studied at 14 loci (AB0, Rhesus, P, Lewis, Kell, HP, GC, C'3, TF, 6-PGD, GLO1, ESD, ACP, and PGM1) of immunogenetic and biochemical polymorphic gene systems. A high frequency of allele d of the Rhesus system was observed in all populations examined (0.399-0.474). Among the rare haplotypes of the Rhesus system, we observed CDE in the Degva population, Cde in the Sergokala and Degva populations, and cdE in the Sergokala and Vanashimakhi populations. The typical Caucasian ACP1c allele of the ACP1 locus, which is rather uncommon, was observed at a relatively high frequency in three (Segokala, Vanashimakhi, and Gubden) of the four local populations under study. In the Lewis system, a high frequency of the Le(a+b+) phenotype, which is characteristic of early childhood, was detected in the adult populations of Sergokala and Degva. The rare PGM1v allele of the phosphoglucomutase 1 system (PGM 1) was additionally observed in the Sergokala population. Statistical analysis identified 19 cases where the observed phenotype frequencies significantly differed from the frequencies expected from the Hardy--Weinberg equilibrium.     

Symbolic ethnicity and symbolic religiosity: Towards a comparison of ethnic and religious acculturation

This article begins with a brief section updating my 1979 Ethnic and Racial Studies article ‘Symbolic ethnicity: the future of ethnic groups and cultures in America’. However, its main aim is to describe and develop the somewhat parallel concept of symbolic religiosity, which I conceive as the consumption of religious symbols apart from regular participation in a religious culture or in religious organizations, for the purpose of expressing feelings of religiosity and religious identification. Since I assume that symbolic religiosity develops mainly among the acculturating descendants of immigrants, I also explore the possibility of separating and then comparing ethnic and religious acculturation. I assume further that among religio‐ethnic groups like the Jews, and ethno‐religious groups such as Russian, Greek and other Orthodox Catholics, ethnic and religious acculturation proceed in divergent ways. This raises a number of interesting empirical questions about the differences between and similarities of ethnicity and religion among these groups and in general. The article concludes with speculations about what might happen to ethnicity and religiosity in the future. Most of my illustrative data in this article are drawn from studies and observations about American Jewry.     

Reproductive skew and group size: an N-person staying incentive model

Transactional models of social evolution emphasize that dominantbreeders may donate parcels of reproduction to subordinatesin return for peaceful cooperation. We develop a general transactionalmodel of reproductive partitioning and group size for N-persongroups when (1) expected group output is a concave (decelerating)functiong[N] of the number N of group members, and (2) thesubordinates may receive fractions of total group reproduction("staying incentives") just sufficient to induce them to stayand help the dominant instead of breeding solitarily. We focusespecially on "saturated" groups, that is, groups that havegrown in size just up to the point where subsequent joining by subordinates is no longer beneficial either to them (in parent-offspring groups) or to the dominant (in symmetric-relatedness groups).Decreased expected output for solitary breeding increases thesaturated group size and decreases the staying incentives.Increased relatedness decreases both the saturated group sizeand the staying incentives. However, in saturated groups withsymmetric relatedness, an individual subordinate's staying incentive converges to 1 — g[N^* — 1]/g[N^*]) regardless ofrelatedness, where N^* is the size of a saturated group, providedthat the g[N] function near the saturated group size N^* isapproximately linear. Thus, staying incentives can be insensitiveto relatedness in saturated groups, although the dominant's total fraction of reproduction (total skew) will be more sensitive.The predicted ordering for saturated group size is: Parent-fullsibling offspring = non-relatives > symmetrically relatedrelatives. Strikingly, stable groups of non-relatives can formfor concaveg[N] functions in our model but not in previousmodels of group size lacking skew manipulation by the dominant.Finally, symmetrical relatedness groups should tend to breakup by threatened ejections of subordinates by dominants, whereas parent-offspring groups should tend to breakup via unforceddepartures by subordinates.     

The relationships of the major group of mammals: New approaches

Systematically, mammals must be the most intensively studied group of organisms. Yet the relationships between the major orders - bats, whales, primates, rodents, insectivores, elephants, and so on - are still controversial. New systematic approaches, including molecular sequencing studies and cladisitic analyses of morphological data, have given rise to a number of new phylogenetic hypotheses, but only a few sister-group relationships seem to have general support. These hypotheses are depicted in the accompanying centre-page diagram.     

Haemoglobinopathies and malaria: new approaches to an old hypothesis

It is almost 40 years since Haldane proposed that high frequencies of thalassaemia and other hoemoglobinopathies might result because these genetic disorders conferred some protection against malaria In the intervening years convincing clinical, epidemiological and in vitro data have been produced to support this 'malaria hypothesis' for haemoglobin S. However, for the numerous other genetic disorders of haemoglobin that are suspected to have been selected in this way it has been much more difficult to provide clearcut evidence. For example, in the case of beta-thalassaemia some but not all epidemiological studies support the hypothesis, while in vitro studies have failed to demonstrate any impairment of either invasion or growth of P. falciparum in affected red cells under physiological conditions.     

Towards writing the encyclopedia of life: an introduction to DNA barcoding

An international consortium of major natural history museums, herbaria and other organizations has launched an ambitious project, the 'Barcode of Life Initiative', to promote a process enabling the rapid and inexpensive identification of the estimated 10 million species on Earth. DNA barcoding is a diagnostic technique in which short DNA sequence(s) can be used for species identification. The first international scientific conference on Barcoding of Life was held at the Natural History Museum in London in February 2005, and here we review the scientific challenges discussed during this conference and in previous publications. Although still controversial, the scientific benefits of DNA barcoding include: (i) enabling species identification, including any life stage or fragment, (ii) facilitating species discoveries based on cluster analyses of gene sequences (e.g. cox1 = CO1, in animals), (iii) promoting development of handheld DNA sequencing technology that can be applied in the field for biodiversity inventories and (iv) providing insight into the diversity of life.