Genome scans provide evidence for low-HDL-C loci on chromosomes 8q23, 16q24.1-24.2, and 20q13.11 in Finnish families

We performed a genomewide scan for genes that predispose to low serum HDL cholesterol (HDL-C) in 25 well-defined Finnish families that were ascertained for familial low HDL-C and premature coronary heart disease. The potential loci for low HDL-C that were identified initially were tested in an independent sample group of 29 Finnish families that were ascertained for familial combined hyperlipidemia (FCHL), expressing low HDL-C as one component trait. The data from the previous genome scan were also reanalyzed for this trait. We found evidence for linkage between the low-HDL-C trait and three loci, in a pooled data analysis of families with low HDL-C and FCHL. The strongest statistical evidence was obtained at a locus on chromosome 8q23, with a two-point LOD score of 4.7 under a recessive mode of inheritance and a multipoint LOD score of 3.3. Evidence for linkage also emerged for loci on chromosomes 16q24.1-24.2 and 20q13.11, the latter representing a recently characterized region for type 2 diabetes. Besides these three loci, loci on chromosomes 2p and 3p showed linkage in the families with low HDL-C and a locus on 2ptel in the families with FCHL.     

The complexity of mitochondrial outer membrane permeability and VDAC regulation by associated proteins

Previous studies have shown that class II β-tubulin plays a key role in the regulation of oxidative phosphorylation (OXPHOS) in some highly differentiated cells, but its role in malignant cells has remained unclear. To clarify these aspects, we compared the bioenergetic properties of HL-1 murine sarcoma cells, murine neuroblastoma cells (uN2a) and retinoic acid - differentiated N2a cells (dN2a). We examined the expression and possible co-localization of mitochondrial voltage dependent anion channel (VDAC) with hexokinase-2 (HK-2) and βII-tubulin, the role of depolymerized βII-tubuline and the effect of both proteins in the regulation of mitochondrial outer membrane (MOM) permeability. Our data demonstrate that neuroblastoma and sarcoma cells are prone to aerobic glycolysis, which is partially mediated by the presence of VDAC bound HK-2. Microtubule destabilizing (colchicine) and stabilizing (taxol) agents do not affect the MOM permeability for ADP in N2a and HL-1 cells. The obtained results show that βII-tubulin does not regulate the MOM permeability for adenine nucleotides in these cells. HL-1 and NB cells display comparable rates of ADP-activated respiration. It was also found that differentiation enhances the involvement of OXPHOS in N2a cells due to the rise in their mitochondrial reserve capacity. Our data support the view that the alteration of mitochondrial affinity for ADNs is one of the characteristic features of cancer cells. It can be concluded that the binding sites for tubulin and hexokinase within the large intermembrane protein supercomplex Mitochondrial Interactosome, could be different between muscle and cancer cells.     

Delayed induced changes in the biochemical composition of host plant leaves during an insect outbreak

In birch, Betula pubescens, herbivore-induced delayed induced resistance (DIR) of defoliated trees may cause a strong reduction in the potential fecundity of a geometrid folivore Epirrita autumnata. In this study, we examined the biochemical basis of DIR in birch leaves during a natural outbreak of E. autumnata. A set of experimental trees was defoliated at four sites by wild larvae in the peak year of the outbreak, whereas control trees were protected from defoliation by spraying with an insecticide. The biochemical composition of leaves was analysed in the following year and, although the DIR response was weak during this outbreak, causing less than a 20% reduction in the potential fecundity of E. autumnata, some consistent relationships between defoliation, biochemistry and pupal mass of E. autumnata suggested a general biochemical basis for the defoliation-induced responses in birch leaves. Total concentrations of nitrogen, sugars and acetone-insoluble residue (e.g. cell wall polysaccharides, cell-wall-bound phenolics, protein, starch, lignin and hemicellulose) were consistently lower, and total concentrations of phenolics, especially of gallotannins and soluble proanthocyanidins, were higher in the leaves of trees defoliated in the previous year than in those protected from defoliation. The capacity of tannins to precipitate proteins correlated with contents of gallotannins, and was highest in defoliated trees. The pupal mass of E. autumnata showed a strong, positive correlation with concentrations of nitrogen and sugars, and a negative correlation with the acetone-insoluble residue and gallotannins in foliage. Correlations with other measured biochemical traits were weak. The correlation coefficients between biochemical traits and pupal mass consistently had similar signs for both defoliated and insecticide–sprayed trees, suggesting that variation in leaf quality due to defoliation in the previous year was based on similar biochemical traits as variation for other reasons. We suggest that DIR is associated with reduced growth activity of leaves, and may be seen as a delay in the biochemical maturation of leaves in defoliated trees. This explains the high concentration of gallotannins in defoliated trees, a characteristic feature of young leaves. However, the lower content of nitrogen and the higher content of soluble proanthocyanidins in defoliated trees are traits usually characterising mature, not young, leaves, indicating defoliation-induced changes in chemistry in addition to modified leaf age. Our results emphasise the importance of understanding the natural changes in chemistry during leaf maturation when interpreting defoliation-induced changes in leaf biochemistry. Received: 26 January 1998 / Accepted: 10 April 1998     

Riqueza y Distribución Ecológica de Especies de Pteridofitas en la Zona del Río Yavarí-Mirín, Amazonía Peruana

We studied the ecological distribution of pteridophytes (ferns and fern allies) along eight 8-km transects covering 12.7 ha in Peruvian Amazonia. Subunits of 200 m² of the transects have previously been classified into four different forest types, and here we document and quantify the floristic differences among these forest types. Pteridophytes have been suggested as an indicator group to classify rain forest habitats, but this requires that the ecological preferences of the species are well documented and consistent across geographic regions. Here we analyzed in detail the distribution and diversity patterns of 130 species across the four rain forest types. Relative species abundance and species diversity were similar among some of the forest types and differed among others, but the species composition differed markedly. Our results largely confirmed the earlier interpretation of the edaphic preferences of the pteridophyte species in western Amazonia. This supports the proposition that deterministic processes have an important role in influencing the floristic composition of Amazonian forests.     

Development of aerobic endurance and repetitive strength in special army unit members

A sample of 25 subjects, members of a Croatian Army special unit, mean age 22 years, underwent a 4.5-month specially programmed kinesiologic training. The aim of the study was to determine the treatment effects on the development of aerobic endurance and repetitive strength as a basis for the development of the capacities needed for acting in urgent combat situations. A battery of nine variables for evaluation of aerobic endurance and repetitive strength was used on four occasions at 6-week intervals. Discriminant functions of differences in the variables between the measurements showed the changes in the capabilities to be ever more pronounced after each of the treatment phases. After the first phase of training, changes in the variables of aerobic endurance were more pronounced than in the repetitive strength variables. The second phase of training was followed by comparable changes in both aerobic endurance and repetitive strength variables, whereas the third phase of training entailed greater changes in the repetitive strength variables than in aerobic endurance.     

Motor abilities at belly dance in elementary female schoolers

The aim of the study was to determine the relation between motor abilities and belly dance performance in elementary school fifth- and sixth-grade female students. A battery of 19 motor tests was used in a sample of 96 students twice, i.e. at the beginning (initial measurement) and at the end (final measurement) of the academic year. On initial measurement, five factors were isolated by the motor space factor analysis: first factor of muscular-aerobic endurance; second factor integrating the strength of legs, coordination of foot and hand movement, and agility; third factor integrating explosive strength of the arms with speed and body coordination; fourth factor defined by flexibility (muscle tone regulation); and fifth factor integrating explosive strength of legs with equilibrium. On final measurement, five factors were isolated as well: first factor as a general one integrating coordination abilities, explosive strength of legs and flexibility; second factor defined by repetitive strength of the trunk and legs; third factor defined by rhythm coordination accompanied by flexibility; fourth factor predominantly defined by equilibrium (accompanied by explosive strength of throwing type and speed); and fifth factor predominantly defined by static strength of arms and legs (accompanied by arm movement frequency). On initial measurement, fourth factor responsible for muscle tone regulation and second factor integrating the strength of legs, coordination of movement frequency of arms and legs, and agility were found to be the best predictors of belly dance performance. In this setting, the tests of forward bow (flexibility) and sit-ups (repetitive strength of abdominal musculature) proved superior in differentiating high performance students and those less successful in belly dance. On final measurement, third factor named rhythm coordination (accompanied by muscle tone regulation) and second factor defined by repetitive strength of the trunk and legs were the best predictors of belly dance performance. In this setting, the tests of rhythm coordination, flexibility tests, tests of repetitive strength of the trunk and legs, and test of aerobic endurance proved superior in differentiating high performance and less successful students in belly dance.     

Biomotor development in 1992 and 2002 samples of seven-year-old children

The aim of the study was to determine quantitative and qualitative differences in the morphological-motor status between elementary school first-graders of both sexes in 1992 and 2002. A standard set of 11 variables currently used in the Croatian school system to evaluate the morphological, motor and functional status of school children was employed at the beginning of academic years in a sample of 635 children (325 male and 310 female) in 1992 and a sample of 850 children (430 male and 420 female) in 2002. The mean age of study children was 7 years (+/- 2 months). Results of canonic discriminative analysis revealed the male children enrolled in elementary school first grade in 2002 to show better performance on the tests of aerobic endurance, static strength and explosive strength, and to have greater mass of muscle tissue and less adipose tissue, while achieving poorer results on the test of movement frequency than their 1992 counterparts. Female children tested in 2002 showed better results on the test of aerobic endurance and all tests of strength factors, with greater mass of muscle tissue and less adipose tissue, while yielding poorer results on the tests of flexibility, coordination and movement frequency as compared with their 1992 counterparts. Factor analysis in the morphological-motor system isolated three varimax factors each in children of both sexes tested in 1992 and 2002. First factor showed a pattern of a general morphological factor predominantly defined by body weight and volume in the children of both sexes from both study years. Second factor showed a pattern of a general motoricity factor predominantly defined by explosive strength, coordination and speed in children tested in 1992, whereas in their 2002 counterparts the general motoricity factor was predominantly defined by the factors of strength and endurance. Third factor was defined by flexibility in both 1992 and 2002 children. In female children tested in 1992, second factor mostly defined energy regulation with predominance of explosive and static strength, followed by coordination, whereas third factor was defined by movement frequency and aerobic endurance. In female children tested in 2002, second factor mostly defined energy regulation with predominance of explosive and repetitive strength, followed by aerobic endurance and coordination, whereas third factor was defined by movement frequency followed by muscle tone regulation.     

Electrostatic interactions modulate the conformation of collagen I

The pH- and electrolyte-dependent charging of collagen I fibrils was analyzed by streaming potential/streaming current experiments using the Microslit Electrokinetic Setup. Differential scanning calorimetry and circular dichroism spectroscopy were applied in similar electrolyte solutions to characterize the influence of electrostatic interactions on the conformational stability of the protein. The acid base behavior of collagen I was found to be strongly influenced by the ionic strength in KCl as well as in CaCl(2) solutions. An increase of the ionic strength with KCl from 10(-4) M to 10(-2) M shifts the isoelectric point (IEP) of the protein from pH 7.5 to 5.3. However, a similar increase of the ionic strength in CaCl(2) solutions shifts the IEP from 7.5 to above pH 9. Enhanced thermal stability with increasing ionic strength was observed by differential scanning calorimetry in both electrolyte systems. In line with this, circular dichroism spectroscopy results show an increase of the helicity with increasing ionic strength. Better screening of charged residues and the formation of salt bridges are assumed to cause the stabilization of collagen I with increasing ionic strength in both electrolyte systems. Preferential adsorption of hydroxide ions onto intrinsically uncharged sites in KCl solutions and calcium binding to negatively charged carboxylic acid moieties in CaCl(2) solutions are concluded to shift the IEP and influence the conformational stability of the protein.