The distinctness and diversity of Ethiopian barleys

 The relative diversity and distinctness of Ethiopian barleys has been investigated using (1) morphology/isozyme/hordein polymorphisms and (2) RFLP markers. In the former a set of 51 landraces from over the whole of Ethiopia was compared with Iranian landraces based on data from previous studies and new hordein data. The two sets of landraces were found to have a comparable diversity. The Ethiopian ones are more diverse morphologically (5 traits), are similar in numbers of alleles per protein locus (17 loci) and in genetic differentiation, but are less diverse in average heterozygosity per locus and degree of polymorphism. However, on the basis of the hordein data the two sources of germplasm are very distinct. The correlation between morphological and protein diversity is very low. In the RFLP study 28 probes evenly distributed across the genome were used to analyse 43 Ethiopian landraces (represented by one single genotype) and to compare them with modern cultivars from North America, Europe and Japan, as well as 3 landraces from Iran, 1 from Nepal, and 1 accession of H. spontaneum from Afghanistan. The major finding was that the Ethiopian germplasm appears to be significantly less diverse than the modern germplasm but that it is genotypically very distinct. The apparent contradiction between a high diversity of useful genes coming from Ethiopia and an apparently low diversity at the DNA level is discussed. Received: 22 July 1996 / Accepted: 26 July 1996     

ESR evidence of superoxide radical dismutation by human ceruloplasmin

The formation of the paramagnetic complex between human ceruloplasmin and radiation produced superoxide radicals was observed by the ESR method at low temperatures. The disappearance of the complex without changes in the oxidation state of copper give the direct evidence that ceruloplasmin, the major antioxidant in serum, is able to dismutate superoxide radicals.     

On the Structure-Bounded Growth Processes in Plant Populations

If growing cells in plants are considered to be composed of increments (ICs) an extended version of the law of mass action can be formulated. It evidences that growth of plants runs optimal if the reaction–entropy term (entropy times the absolute temperature) matches the contact energy of ICs. Since these energies are small, thermal molecular movements facilitate via relaxation the removal of structure disturbances. Stem diameter distributions exhibit extra fluctuations likely to be caused by permanent constraints. Since the signal–response system enables in principle perfect optimization only within finite-sized cell ensembles, plants comprising relatively large cell numbers form a network of size-limited subsystems. The maximal number of these constituents depends both on genetic and environmental factors. Accounting for logistical structure–dynamics interrelations, equations can be formulated to describe the bimodal growth curves of very different plants. The reproduction of the S-bended growth curves verifies that the relaxation modes with a broad structure-controlled distribution freeze successively until finally growth is fully blocked thus bringing about “continuous solidification”.     

Patch occupancy and abundance of local populations in landscapes differing in degree of habitat fragmentation: a case study of the colonial black‐headed gull,Chroicocephalus ridibundus

Aim This study investigated whether habitat fragmentation at the landscape level influences patch occupancy and abundance of the black‐headed gull, Chroicocephalus ridibundus, and whether the response of the species to environmental factors is consistent across replicated landscape plots. Location Water bodies (habitat patches) in southern Poland. Methods Surveys were conducted in two landscape types (four plots in each): (1) more‐fragmented landscape, in which habitat patches were small (mean size 2.2–6.2 ha) and far apart (mean distance 2.5–3.1 km); and (2) less‐fragmented landscape, in which habitat patches were large (mean size 9.2–16.5 ha) and separated by short distances (mean 0.9–1.4 km). Observations were performed twice in 284 potential habitat patches during the 2007 breeding season. Results Colonies were significantly more frequent and larger in the less‐fragmented landscapes than in the more‐fragmented ones. Probability of patch occupancy and number of breeding birds were positively related with patch size and these relationships were especially strong in the more‐fragmented landscapes. In the less‐fragmented landscapes, the occurrence of black‐headed gulls was negatively related to the distance to the nearest local population, but in the more‐fragmented landscapes such a relationship was not detected. As distance to the nearest habitat patch increased, the probability of the patch occupancy decreased in the more‐fragmented landscapes. Moreover, abundance was negatively influenced by distance to the nearest habitat patch, especially strongly in more‐fragmented landscapes. Proximity of corridors (rivers) positively influenced the occupation of patches regardless of landscape type. The number of islets positively influenced occupancy and abundance of local populations, and this relationship was stronger in the more‐fragmented landscapes. Main conclusions Our results are in agreement with predictions from metapopulation theory and are the first evidence that populations of black‐headed gulls may have a metapopulation structure. However, patch occupancy and abundance were differentially affected by explanatory variables in the more‐fragmented landscapes than in the less‐fragmented ones. This implies that it is impossible to derive, a priori, predictions about presence/abundance patterns based on only a single landscape.     

Myocardium proteome remodelling after nutritional deprivation of methyl donors

Methyl donor (MD: folate, vitamin B12 and choline) deficiency causes hyperhomocysteinemia, a risk factor for cardiovascular diseases. However, the mechanisms of the association between MD deficiency, hyperhomocysteinemia, and cardiomyopathy remain unclear. Therefore, we performed a proteomic analysis of myocardium of pups from rat dams fed a MD-depleted diet to understand the impact of MD deficiency on heart at the protein level. Two-dimension gel electrophoresis and mass spectrometry-based analyses allowed us to identify 39 proteins with significantly altered abundance in MD-deficient myocardium. Ingenuity Pathway Analysis showed that 87% of them fitted to a single protein network associated with developmental disorder, cellular compromise and lipid metabolism. Concurrently increased protein carbonylation, the major oxidative post-translational protein modification, could contribute to the decreased abundance of many myocardial proteins after MD deficiency. To decipher the effect of MD deficiency on the abundance of specific proteins identified in vivo, we developed an in vitro model using the cardiomyoblast cell line H9c2. After a 4-day exposure to a MD-deprived (vs. complete) medium, cells were deficient of folate and vitamin B12, and released abnormal amounts of homocysteine. Western blot analyses of pup myocardium and H9c2 cells yielded similar findings for several proteins. Of specific interest is the result showing increased and decreased abundances of prohibitin and α-crystallin B, respectively, which underlines mitochondrial injury and endoplasmic reticulum stress within MD deficiency. The in vitro findings validate the MD-deficient H9c2 cells as a relevant model for studying mechanisms of the early metabolic changes occurring in cardiac cells after MD deprivation.     

Night shift work and osteoporosis among female blue-collar workers in Poland - a pilot study

ABSTRACT

Osteoporosis is an important public health problem worldwide. Although a number of factors that affect bone structure have been described; thus far, the current knowledge of occupational factors that may have an influence on bone tissue metabolism is strongly limited. Published studies indicate night shift work and the related circadian rhythm disruption may be considered as plausible underlying factors. The aim of the present study was to assess the potential association between night shift work and bone mineral density (BMD) among female blue-collar workers in Poland. A cross-sectional study was carried out among 194 female blue-collar workers >40 years of age employed in industrial plants. The operating system of work consisted of three work shifts clockwise rotation: morning (06:00–14:00 h), afternoon (14:00–22:00 h), and night (22:00–06:00 h), with five consecutive shifts per week followed by a free weekend. A questionnaire survey, based on a Polish version of The European vertebral osteoporosis study (EVOS) questionnaire, a validated instrument, was administered. Data on current job characteristics, job seniority, and lifetime duration of night shift work were also collected. BMD of the lumbar spine and hip (both total femur and femoral neck) was measured using dual-energy X-ray absorptiometry. Multivariate linear regression models were run, with bone mineralization parameters as dependent variables, as well as night work characteristics and important confounders. Statistical analysis was performed separately for premenopausal and postmenopausal women. The analyses adjusted for confounders did not reveal any significant differences between current or lifetime experience of night shift work and BMD among both premenopausal and postmenopausal women. However, the outcomes supported the well-established correlation with factors, such as age, BMI, and menopausal status. BMD at the three sites measured was significantly associated with BMI (p < .001) and inversely associated with age (p < .001) in the total study population. Postmenopausal women had significantly lower BMD than did premenopausal women (p < .001). The study findings indicate that in the population of Polish female blue-collar workers, the system of work does not seem to be associated with the development of osteoporosis.     

Generation of supercoils in nicked and gapped DNA drives DNA unknotting and postreplicative decatenation

Due to the helical structure of DNA the process of DNA replication is topologically complex. Freshly replicated DNA molecules are catenated with each other and are frequently knotted. For proper functioning of DNA it is necessary to remove all of these entanglements. This is done by DNA topoisomerases that pass DNA segments through each other. However, it has been a riddle how DNA topoisomerases select the sites of their action. In highly crowded DNA in living cells random passages between contacting segments would only increase the extent of entanglement. Using molecular dynamics simulations we observed that in actively supercoiled DNA molecules the entanglements resulting from DNA knotting or catenation spontaneously approach sites of nicks and gaps in the DNA. Type I topoisomerases, that preferentially act at sites of nick and gaps, are thus naturally provided with DNA–DNA juxtapositions where a passage results in an error-free DNA unknotting or DNA decatenation.