History, genetic differentiation and conservation strategies for disjunct populations of Sibiraea species from Southeastern Europe and Asia

The genetic structure of Croatian Sibirea (Sibiraea croatica), a rare and endemic tertiary relic of Croatian and Herzegovinian flora, and its relationship with sibirea from Southern Russia and Southern Siberia (Sibiraea altaiensis) was studied using amplification, restriction and sequencing of the ITS region in genomic DNA and cpDNA and their comparisons with sequences of the Rosaceae species obtained from GenBank. The restriction analysis and separation in agarose gel showed no differences in length of the digested cpDNA between or within populations. Sequencing showed only minor variability between populations. Only a minor difference of 6 bp duplication in DNA amplified with ccmp 10-R and trnM primer pair was noticed in two geographically distinct populations. No differences in the restriction pattern for the ITS region in genomic rDNA indicates that all samples of sibirea belong to the same species since the ITS region was proven to be conserved within one taxonomic species. The minor differences that were␣obtained support the hypothesis that sibirea is an old tertiary relic that shows a minor variability, confirming previous preliminary results from comparisons of the Croatian and Altaic sibireas at the morphological level. Our data suggests that Croatian sibirea from the Balkan is a disjunct population identical to the Altaic species. Due to its disjunct occurrence in Southeastern Europe, the endemic status in the Dinarics, a relic that survived the glaciations, it deserves active conservation approaches through support of traditional use of high-mountain pastures for reducing natural reforestation of sibirea ancient sites.     

Osteosarcoma arising from osteochondroma of the tibia: case report and cytogenetic findings

Osteochondroma is a cartilage capped benign tumor developing mainly at the juxta-epiphyseal region of long bones. The rate of malignant transformation, mainly into chondrosarcoma, is estimated to be less than 1-3%. Transformation into osteosarcoma is very rare and has been reported only thirteen times. There is little information on treatment and outcome. We report the case of a secondary osteosarcoma arising in the left tibia of a 23-year-old male, 10 years after the initial diagnosis of osteochondroma and after two partial resections. Malignant transformation occurred at the stalk and not at the cartilage cap, as would normally be expected. Chromosome banding analysis revealed the karyotype: 46,XY, t(3;13)(q21;q34) [2]/46,XY [18]. Records from additional cases will help determine the parameters that define these rare secondary bone lesions.     

UV-B-induced Inhibition of Stem Elongation and Leaf Expansion in Pea Depends on Modulation of Gibberellin Metabolism and Intact Gibberellin Signalling

Information on the involvement of elongation-controlling hormones, particularly gibberellin (GA), in UV-B modulation of stem elongation and leaf growth, is limited. We aimed to study the effect of UV-B on levels of GA and indole-3-acetic acid (IAA) as well as involvement of GA in UV-B inhibition of stem elongation and leaf expansion in pea. Reduced shoot elongation (13%) and leaf area (37%) in pea in response to a 6-h daily UV-B (0.45 W m^?2) exposure in the middle of the light period for 10 days were associated with decreased levels of the bioactive GA₁ in apical stem tissue (59%) and young leaves (69%). UV-B also reduced the content of IAA in young leaves (35%). The importance of modulation of GA metabolism for inhibition of stem elongation in pea by UV-B was confirmed by the lack of effect of UV-B in the le GA biosynthesis mutant. No UV-B effect on stem elongation in the la cry-s (della) pea mutant demonstrates that intact GA signalling is required. In conclusion, UV-B inhibition of shoot elongation and leaf expansion in pea depends on UV-B modulation of GA metabolism in shoot apices and young leaves and GA signalling through DELLA proteins. UV-B also affects the IAA content in pea leaves.     

Ultrastructure of fat body cells and Malpighian tubule cells in overwintering <Emphasis Type="Italic">Scoliopteryx libatrix</Emphasis> (Noctuoidea)

The herald moths, Scoliopteryx libatrix, overwinter in hypogean habitats. The ultrastructure of their fat body (FB) cells and Malpighian tubule (MT) epithelial cells was studied by light microscopy and transmission electron microscopy, and essential biometric and biochemical measurements were performed. The FB was composed of adipocytes and sparse urocytes. The ultrastructure of both cells did not change considerably during this natural starvation period, except for rough endoplasmic reticulum (rER) which became more abundant in March females. In the cells, the reserve material consisted of numerous lipid droplets, glycogen rosettes, and protein granula. During overwintering, the lipid droplets diminished, and protein granula became laminated. The MTs consisted of a monolayer epithelium and individual muscle cells. The epithelial cells were attached to the basal lamina by numerous hemidesmosomes. The apical plasma membrane was differentiated into numerous microvilli, many of them containing mitochondria. Nuclei were surrounded by an abundant rER. There were numerous spherites in the perinuclear part of the cells. The basal plasma membrane formed infoldings with mitochondria in between. Nuclei were located either in the basal or in the central part of the cells. During overwintering, spherites were gradually exploited, and autophagic structures appeared: autophagosomes, autolysosomes, and residual bodies. There were no statistical differences between the sexes in any measured biometric and biochemical variables in the same time frames. The energy-supplying lipids and glycogen, and spherite stores were gradually spent during overwintering. In March, the augmented rER signified the intensification of synthetic processes prior to the epigean ecophase.     

Hyper-osmotic cell volume regulation in vivo and in vitro in flounder (Platichthys flesus) heart ventricles

Summary Cell volume regulation in heart ventricles of the flounderPlatichthys flesus has been studied under hyper-osmotic conditions in vivo and in vitro.During reacclimation of flounders from fresh water to sea water the osmolality of blood plasma increased to the sea water level in 7 days. The water content of the heart ventricle cells remained constant after reacclimation while the intracellular concentration of K⁺ and taurine increased to values found in sea water flounders.Hearts taken from fresh water flounders were mounted in vitro and perfused with hyper-osmotic ringer solution. Upon perfusion the cellular water content of the ventricle decreased initially but then steadily increased. After 6 h the cellular water content was still below the control values reflecting that the ventricle cells have an incomplete volume regulation in a hyper-osmotic medium. The cellular amount of K⁺ and taurine increased during the volume regulation. The perfusion media did not contain taurine or amino acids and the gain in cellular taurine must be due to intracellular production.     

Mathematical and Live Meningococcal Models for Simple Sequence Repeat Dynamics – Coherent Predictions and Observations

Evolvability by means of simple sequence repeat (SSR) instability is a feature under the constant influence of opposing selective pressures to expand and compress the repeat tract and is mechanistically influenced by factors that affect genetic instability. In addition to direct selection for protein expression and structural integrity, other factors that influence tract length evolution were studied. The genetic instability of SSRs that switch the expression of antibiotic resistance ON and OFF was modelled mathematically and monitored in a panel of live meningococcal strains. The mathematical model showed that the SSR length of a theoretical locus in an evolving population may be shaped by direct selection of expression status (ON or OFF), tract length dependent (α) and tract length independent factors (β). According to the model an increase in α drives the evolution towards shorter tracts. An increase in β drives the evolution towards a normal distribution of tract lengths given that an upper and a lower limit are set. Insertion and deletion biases were shown to skew allelic distributions in both directions. The meningococcal SSR model was tested in vivo by monitoring the frequency of spectinomycin resistance OFF→ON switching in a designed locus. The instability of a comprehensive panel of the homopolymeric SSRs, constituted of a range of 5–13 guanine nucleotides, was monitored in wildtype and mismatch repair deficient backgrounds. Both the repeat length itself and mismatch repair deficiency were shown to influence the genetic instability of the homopolymeric tracts. A possible insertion bias was observed in tracts ≤G₁₀. Finally, an inverse correlation between the number of tract-encoded amino acids and growth in the presence of ON-selection illustrated a limitation to SSR expansion in an essential gene associated with the designed model locus and the protein function mediating antibiotic resistance.     

Risk Factors for Sporadic Domestically Acquired Campylobacter Infections in Norway 2010–2011: A National Prospective Case-Control Study

BackgroundCampylobacteriosis is the most frequently reported food- and waterborne infection in Norway. We investigated the risk factors for sporadic Campylobacter infections in Norway in order to identify areas where control and prevention measures could be improved.MethodsA national prospective case-control study of factors associated with Campylobacter infection was conducted from July 2010 to September 2011. Cases were recruited from the Norwegian Surveillance System of Communicable Diseases (MSIS). Controls were randomly selected from the Norwegian Population Registry. Cases and controls were mailed a paper questionnaire with a prepaid return envelope. Univariable analyses using logistic regression were conducted for all exposures. A final parsimonious multivariable model was developed using regularized/penalized logistic regression, and adjusted odds ratios were calculated.ResultsA total of 995 cases and 1501 controls were included in the study (response proportion 55% and 30%, respectively). Exposures that had significant increases in odds of Campylobacter infection in multivariable analysis were drinking water directly from river, stream, or lake (OR: 2.96), drinking purchased bottled water (OR: 1.78), eating chicken (1.69), eating meat that was undercooked (OR: 1.77), eating food made on a barbecue (OR: 1.55), living on a farm with livestock (OR: 1.74), having a dog in the household (OR: 1.39), and having household water supply serving fewer than 20 houses (OR: 1.92).ConclusionsConsumption of poultry and untreated water remain important sources of Campylobacter infection in Norway, despite ongoing control efforts. The results justify the need for strengthening education for consumers and food handlers about the risks of cross-contamination when preparing poultry and with consuming raw or undercooked chicken. The public should also be reminded to take precautions when drinking untreated water in nature and ensure continued vigilance in order to protect and maintain the quality of water from small-scale water supply systems.