Can a benthic diatom community complement chemical analyses and discriminate between disturbed and undisturbed saline wetland habitats? A study of seven soda pans in Serbia

Soda pans are protected in the European Union as Natura 2000 areas in the category of “Pannonic saline steppes and marshes”. There are at least six soda pans of reference status in Serbia and only a half have strict legal protection. The number of similar, but disturbed (modified) habitats that could be reconstructed is still unknown. We conducted sampling in five natural and two disturbed soda pans aiming to compare a difference in physical and chemical water properties and benthic diatom communities. In addition, we tried to apply recently developed Diatom Index for Soda Pans (DISP) and Trait-based index (TBI) to test the applicability of taxonomic and trait-based approaches in ecological status assessment of soda pans in the southern part of the Carpathian Basin. In contrast to natural soda pans, lower pH and nutrients levels were recorded in disturbed pans. A total of 86 taxa of benthic diatoms, including 11 new for diatom flora of Serbia, were identified. A lower species richness and Shannon index was recorded in natural soda pans. Nitzschia austriaca, N. supralitorea, Navicula veneta and N. wiesneri were dominant diatoms in soda pans of the reference status. Both diatom indices were in average lower in disturbed pans, and this difference was statistically significant for DISP index. We concluded that two indices, supplemented with indicator values for some local diatom species, can be a promising tool for soda pan conservation in this part of the Carpathian Basin.

     

Inhibition of Na+/K+-ATPase and Mg2+-ATPase by metal ions and prevention and recovery of inhibited activities by chelators

Kinetics and inhibition of Na⁺/K⁺-ATPase and Mg²⁺-ATPase activity from rat synaptic plasma membrane (SPM), by separate and simultaneous exposure to transition (Cu²⁺, Zn²⁺, Fe²⁺ and.Co²⁺) and heavy metals (Hg²⁺and Pb²⁺) ions were studied. All investigated metals produced a larger maximum inhibition of Na⁺/K⁺-ATPase than Mg²⁺-ATPase activity. The free concentrations of the key species (inhibitor, MgATP^{2 ?} , MeATP^{2 ?} ) in the medium assay were calculated and discussed. Simultaneous exposure to the combinations Cu²⁺/Fe²⁺ or Hg²⁺/Pb²⁺caused additive inhibition, while Cu²⁺/Zn²⁺ or Fe²⁺/Zn²⁺ inhibited Na⁺/K⁺-ATPase activity synergistically (i.e., greater than the sum metal-induced inhibition assayed separately). Simultaneous exposure to Cu²⁺/Fe²⁺ or Cu²⁺/Zn²⁺ inhibited Mg²⁺-ATPase activity synergistically, while Hg²⁺/Pb²⁺ or Fe²⁺/Zn²⁺ induced antagonistic inhibition of this enzyme. Kinetic analysis showed that all investigated metals inhibited Na⁺/K⁺-ATPase activity by reducing the maximum velocities (V_max) rather than the apparent affinity (K_m) for substrate MgATP^2-, implying the noncompetitive nature of the inhibition. The incomplete inhibition of Mg²⁺-ATPase activity by Zn²⁺, Fe²⁺ and Co²⁺ as well as kinetic analysis indicated two distinct Mg²⁺-ATPase subtypes activated in the presence of low and high MgATP^{2 ?} concentration. EDTA, L-cysteine and gluthathione (GSH) prevented metal ion-induced inhibition of Na⁺/K⁺-ATPase with various potencies. Furthermore, these ligands also reversed Na⁺/K⁺-ATPase activity inhibited by transition metals in a concentration-dependent manner, but a recovery effect by any ligand on Hg²⁺-induced inhibition was not obtained.     

Salinity stress response of non-transformed and AtCKX transgenic centaury (Centaurium erythraea Rafn.) shoots and roots grown in vitro

Common centaury (Centaurium erythraea Rafn.) is a plant species that can inhabit saline soils. It is known as a plant with high spontaneous regeneration potential in vitro. In the present work we evaluated shoots and roots salinity tolerance of non-transformed and three AtCKX transgenic centaury lines to graded NaCl concentrations (0, 50, 100, 150, 200 mM) in vitro. Overexpression of AtCKX genes in transgenic centaury plants resulted in an altered cytokinins (CKs) profile leading to a decline of bioactive CK levels and, at the same time, increased contents of storage CK forms, inactive CK forms and/or CK nucleotides. Significant increment of fresh shoot weight was obtained in shoots of non-transformed and AtCKX1 transgenic line only on medium supplemented with 50 mM NaCl. However two analysed AtCKX2 transgenic lines reduced shoot growth at all NaCl concentrations. In general, centaury roots showed higher tolerance to salinity than shoots. Non-transformed and AtCKX1 transgenic lines tolerated up to 100 mM NaCl without change in frequency of regeneration and number of regenerated plants. Roots of two analysed AtCKX2 transgenic lines showed different regeneration potential under salt stress. Regeneration of transgenic AtCKX2-26 shoots even at 200 mM NaCl was recorded. Salinity stress response of centaury shoots and roots was also evaluated at biochemical level. Free proline, malondialdehyde and hydrogen peroxide content as well as antioxidative enzymes activities were investigated in shoots and roots after 1, 2, 4 and 8 weeks. In general, adition of NaCl in culture medium elevated all biochemical parameters in centaury shoots and in roots. Considering that all analysed AtCKX transgenic centaury lines showed altered salt tolerance to graded NaCl concentrations in vitro it can be assumed that CKs might be involved in plant defence to salt stress conditions.     

Skeletal Manifestations of Hydatid Disease in Serbia: Demographic Distribution,Site Involvement,Radiological Findings,and Complications

Although Serbia is recognized as an endemic country for echinococcosis, no information about precise incidence in humans has been available. The aim of this study was to investigate the skeletal manifestations of hydatid disease in Serbia. This retrospective study was conducted by reviewing the medical database of Institute for Pathology (Faculty of Medicine in Belgrade), a reference institution for bone pathology in Serbia. We reported a total of 41 patients with bone cystic echinococcosis (CE) during the study period. The mean age of 41 patients was 40.9±18.8 years. In 39% of patients, the fracture line was the only visible radiological sign, followed by cyst and tumefaction. The spine was the most commonly involved skeletal site (55.8%), followed by the femur (18.6%), pelvis (13.9%), humerus (7.0%), rib (2.3%), and tibia (2.3%). Pain was the symptom in 41.5% of patients, while some patients demonstrated complications such as paraplegia (22.0%), pathologic fracture (48.8%), and scoliosis (9.8%). The pathological fracture most frequently affected the spine (75.0%) followed by the femur (20.0%) and tibia (5.0%). However, 19.5% of patients didn''t develop any complication or symptom. In this study, we showed that bone CE is not uncommon in Serbian population. As reported in the literature, therapy of bone CE is controversial and its results are poor. In order to improve the therapy outcome, early diagnosis, before symptoms and complications occur, can be contributive.     

Characterization of the Variability of Epstein-Barr Virus Genes in Nasopharyngeal Biopsies: Potential Predictors for Carcinoma Progression

Epstein-Barr virus (EBV) infection is a significant factor in the pathogenesis of nasopharyngeal carcinoma, especially in the undifferentiated carcinoma of nasopharyngeal type (UCNT, World Health Organization type III), which is the dominant histopathological type in high-risk areas. The major EBV oncogene is latent membrane protein 1 (LMP1). LMP1 gene shows variability with different tumorigenic and immunogenic potentials. EBV nuclear antigen 1 (EBNA1) regulates progression of EBV-related tumors; however, the influence of EBNA1 sequence variability on tumor pathogenesis is controversial. The aims of this study were to characterize polymorphisms of EBV genes in non-endemic nasopharyngeal carcinoma biopsies and to investigate potential sequence patterns that correlate with the clinical presentation of nasopharyngeal carcinoma. In total, 116 tumor biopsies of undifferentiated carcinoma of nasopharyngeal type (UCNT), collected from 2008 to 2014, were evaluated in this study. The genes EBNA2, LMP1, and EBNA1 were amplified using nested-PCR. EBNA2 genotyping was performed by visualization of PCR products using gel electrophoresis. Investigation of LMP1 and EBNA1 included sequence, phylogenetic, and statistical analyses. The presence of EBV DNA was significantly distributed between TNM stages. LMP1 variability showed six variants, with the detection of the first China1 and North Carolina variants in European nasopharyngeal carcinoma biopsies. Newly discovered variants Srb1 and Srb2 were UCNT-specific LMP1 polymorphisms. The B95-8 and North Carolina variants are possible predictors for favorable TNM stages. In contrast, deletions in LMP1 are possible risk factors for the most disfavorable TNM stage, independent of EBNA2 or EBNA1 variability. A newly discovered EBNA1 subvariant, P-thr-sv-5, could be a potential diagnostic marker, as it represented a UCNT-specific EBNA1 subvariant. A particular combination of EBNA2, LMP1, and EBNA1 polymorphisms, type 1/Med/P-thr was identified as a possible risk factor for TNM stage IVB or progression to the N3 stage.     

A role for alphaV integrin subunit in TGF-beta-stimulated osteoclastogenesis

TGF-beta increases bone resorption in vivo and greatly increases osteoclast formation stimulated by receptor activator of NF-kappaB ligand (RANKL) in vitro. TGF-beta does not independently affect the differentiation state of RAW264.7 preosteoclasts, but increases cell attachment to vitronectin. This effect is mediated by increased expression of alphaV integrin subunit mRNA and protein. Concomitant with induction of osteoclast differentiation, RANKL causes relocation of alphaV to focal sites in the cell. This effect is potentiated by TGF-beta. Integrin blockade disrupts both attachment to vitronectin and RANKL-induced osteoclast formation, but culture on vitronectin has little effect. Ectopic expression of alphaV stimulates multinucleation of RAW264.7 cells and increases the number of osteoclasts formed in the presence of RANKL. These data suggest that TGF-beta potentiates RANKL-induced osteoclast formation, in part by increased expression of the alphaV integrin subunit, which may contribute to cell fusion.