Body mass and body fat in Hungarian schoolboys: differences between 1980-2005

The prevalence of juvenile excess weight keeps growing in the more developed world (WHO, 1998). The aim of the study was to compare the prevalence of overweight and obesity in Hungarian schoolboys in 1980 and 2005.Two independent representative data collections were performed in volunteer boys aged between 6.51 and 18.50 years in the same 90 settlements of the country in 1980 (n=13,061) and 2005 (n=13,060). Height, body mass, and five skinfolds were measured by the same investigators in both instances. Overweight and obesity were estimated by using BMI (Cole et al., 2000), respectively skinfold thicknesses (Parízková, 1961).The pair-wise differences between height means were consistently significant in the 12 age groups studied. Body mass differences were not exactly proportionate with height. The boys of 2005 had significantly more relative body fat than those of 1980. The prevalence of overweight and obesity was remarkably higher in 2005.Taller height and a part of the heavier body mass in 2005 was attributed to a positive secular growth trend. The increases in BMI and fat content are negative consequences of a markedly changed lifestyle associated with inactivity and dietary habits. Because of its public health importance the trends of childhood obesity should be closely monitored.     

Conservation of the drought-inducible DS2 genes and divergences from their ASR paralogues in solanaceous species.

The drought-inducible DS2 genes of potatoes are members of the ASR (abscisic acid, stress and ripening) gene family. Previously it was shown that expression of DS2 genes is highly dehydration-specific in potato leaves, is not inducible by cold, heat, salt, hypoxia or oxidative stresses, and is independent of abscisic acid (ABA). Now it is shown that StDS2 does not respond either to sucrose or any plant hormones. Conservation of DS2 genes with this unique mode of regulation was studied in the solanaceous species with different relationships to potatoes. DS2 orthologues were identified by DNA sequence alignment in the closely related Lycopersicon and Capsicum species but not in the more distantly related Nicotiana sp. DNA and RNA gel blot analysis revealed the presence of a gene highly homologous to the potato gene StDS2 in tomato (LeDS2) with the same desiccation-specific expression in leaves and organ-specific expression in flowers and green fruits. The LeDS2 promoter was isolated and found to be almost identical in sequence with the promoter of StDS2, except for a 45-bp insertion in tomato. In contrast, no gene highly similar to StDS2 was detected in Nicotiana species on DNA gel blots. Neither StDS2 nor LeDS2 promoter regions were able to confer expression for the beta-glucuronidase (GUS) reporter gene in transgenic tobacco plants indicating that the trans regulatory factors necessary for DS2 expression are not conserved either in Nicotiana tabacum. These data suggest a narrow species-specificity and late evolution of the DS2-type genes within the family Solanaceae.     

Control of water-use efficiency by florigen

A major issue in modern agriculture is water loss through stomata during photosynthetic carbon assimilation. In water-limited ecosystems, annual plants have strategies to synchronize their growth and reproduction to the availability of water. Some species or ecotypes of flowers are early to ensure that their life cycles are completed before the onset of late season terminal drought (“drought escape”). This accelerated flowering correlates with low water-use efficiency (WUE). The molecular players and physiological mechanisms involved in this coordination are not fully understood. We analyzed WUE using gravimetry, gas exchange, and carbon isotope discrimination in florigen deficient (sft mutant), wild-type (Micro-Tom), and florigen over-expressing (SFT-ox) tomato lines. Increased florigen expression led to accelerated flowering time and reduced WUE. The low WUE of SFT-ox was driven by higher stomatal conductance and thinner leaf blades. This florigen-driven effect on WUE appears be independent of abscisic acid (ABA). Our results open a new avenue to increase WUE in crops in an ABA-independent manner. Manipulation of florigen levels could allow us to produce crops with a life cycle synchronized to water availability.     

Recombination and mating-type switching in a ligase-defective mutant of Schizosaccharomyces pombe

Summary The ligase-defective cdc17-L16 mutant of Schizosaccharomyces pombe var. pombe was tested for genetic recombination and mating-type switching. Mitotic recombination was studied in both haploid and heteroallelic diploid cells. Cells carrying a heteroallelic ade6 duplication constructed by Schuchert and Kohli were tested for ectopic genetic recombination. We have found that cdc17-L16 is a mitotic hyper-rec mutant, as it increases the instability of the duplication by a factor of about 6 even at the permissive temperature of 23° C. In diploid cells, the enhancement of recombination rates detected was to that of cdc17 ⁺ cells. The temperature-sensitive cell cycle defect is also associated with a reduced level of mating and sporulation but does not significantly affect mating-type switching and intragenic meiotic recombination. It is supposed that the mitotic hyper-rec phenotype is a secondary result of insufficient repair of DNA breaks, while the lack of influence of the reduced ligase activity on the latter two processes might be attributed to their peculiar initiation mechanisms.     

Interresidue interactions in protein classes

The free energy difference between folded and unfolded state is about the same for most proteins and it is not more than the energy of a few noncovalent interactions. In addition to the numerous noncovalent interactions, some proteins contain one or more disulfide bonds, which, as covalent crosslinks, significantly stabilize their tertiary structure. Correlation between the presence of disulfide bond(s), and the number noncovalent interresidue interactions of various kinds is analyzed here. The number of interactions per residue is almost the same for all protein. Also the number of long-range interactions per residue is the same in all proteins. Proteins with S(SINGLE BOND)S bond(s) (extracellular proteins) have more medium-range and fewer short-range interactions than those without S(SINGLE BOND)S bonds. However, the difference is independent of the number of these covalent crosslinks. We concluded that the different distributions of the various kinds of noncovalent interaction reflect the needs of proteins in the different environments, the extracellular and the intracellular ones, rather than the presence of the disulfide bond(s). We also pointed out that the observed differences in the distributions of short- and medium-range interactions are in good agreement with different secondary structure compositions of extracellular and intracellular proteins. Proteins 27:360–366, 1997. © 1997 Wiley-Liss, Inc.     

Visual Ecology and Perception of Coloration Patterns by Domestic Chicks

This article suggests how we might understand the way potential predators see coloration patterns used in aposematism and visual mimicry. We start by briefly reviewing work on evolutionary function of eyes and neural mechanisms of vision. Often mechanisms used for achromatic vision are accurately modeled as adaptations for detection and recognition of the generality of optical stimuli, rather than specific stimuli such as biological signals. Colour vision is less well understood, but for photoreceptor spectral sensitivities of birds and hymenopterans there is no evidence for adaptations to species-specific stimuli, such as those of food or mates. Turning to experimental work, we investigate how achromatic and chromatic stimuli are used for object recognition by foraging domestic chicks (Gallus gallus). Chicks use chromatic and achromatic signals in different ways: discrimination of large targets uses (chromatic) colour differences, and chicks remember chromatic signals accurately. However, detection of small targets, and discrimination of visual textures requires achromatic contrast. The different roles of chromatic and achromatic information probably reflect their utility for object recognition in nature. Achromatic (intensity) variation exceeds chromatic variation, and hence is more informative about change in reflectance – for example, object borders, while chromatic signals yield more information about surface reflectance (object colour) under variable illumination. This revised version was published online in July 2006 with corrections to the Cover Date.     

Abscisic acid and auxin accumulation in Catasetum fimbriatum roots growing in vitro with high sucrose and mannitol content

Endogenous contents of indolyl-3-acetic acid (IAA) and abscisic acid (ABA) were quantified in excised roots of Catasetum fimbriatum (Orchidaceae) cultured in vitro on solidified Vacin and Went medium with 1, 2, 4, 6, 8 and 10 % sucrose, as well as 2 % sucrose plus mannitol. Maximum root growth was observed in media with 4 % sucrose and 2 % sucrose plus 2.2 % mannitol, suggesting that a moderate water or osmotic stress promotes orchid root growth. Contents of both ABA and IAA increased in parallel to increasing sucrose concentration and a correlation between root elongation and the ABA/IAA ratio was observed. Incubating isolated C. fimbriatum roots with radiolabeled tryptophan, we showed an accumulation of IAA and its conjugates.