Cytotoxicity and cytoprotective activity in naphthalenediols depends on their tendency to form naphthoquinones

We consider the cytotoxicity and the protection against oxidative stress for members of the naphthalenediol family and the known antioxidant epigallocatechin gallate (EGCG). Compounds include the 1,2-naphthalenediol (1,2-ND), 1,4-ND, 2,3-ND, 1,8-ND, and 1,4-dipropyl-2,3-naphthalenediol (DPND). The cell line is an adherent clone of rat pheochromocytoma (PC12-AC). Oxidative stress was induced by the peroxyl radical generator AAPH. The relative order of cytotoxicity was 1,4-ND > 1,2-ND > DPND > 2,3-ND > 1,8-ND > EGCG, with EC(50)'s of 15, 40, 160, >250, >250, >250 muM, respectively. Despite their high toxicity, both 1,4-ND and 1,2-ND showed narrow zones of protective behavior whereas DPND, 2,3-ND and 1,8-ND and especially EGCG showed an extended protective range. The total protection obtained for the combination of cells/oxidative stressor/protective compounds (PC12-AC/AAPH/naphthalenediols) was defined by an integrated measure, the cytoprotective area (CPA). We relate the observed cytotoxicity and CPA to the different electronic structures of the naphthalenediols, characterized by the first and second bond dissociation enthalpies and the pK(a)'s for parent (diol) and semiquinone. Since the 2,3- and 1,8-naphthalenediols do not form quinones, their cytotoxicity is much lower than for the compounds which do. Thus selected members of the naphthalenediol family show promise as antioxidants.     

New Remains of the Multituberculate Mammal <Emphasis Type="Italic">Barbatodon</Emphasis> from the Upper Cretaceous of the Hațeg Basin (Romania)

The so-called “Ha?eg Island” (Transylvania, Romania) is well known for its rich and peculiar Late Cretaceous vertebrate assemblages, including dwarf dinosaurs, first reported at the end of the 19th century. Besides dinosaurs, other important members of the “Ha?eg Island” terrestrial ecosystems were the multituberculate mammals. Late Cretaceous (Maastrichtian) multituberculates are extremely rare in Europe, being known exclusively from the “Ha?eg Island.” Two genera are reported from this area: Kogaionon, with the single species K. ungureanui, and Barbatodon, with two species: B. transylvanicus and B. oardaensis. Both genera belong to the European endemic family Kogaionidae. We report herein new remains of B. transylvanicus from the Maastrichtian locality of Pui (Hunedoara District) in the Ha?eg Basin, including the most complete dentaries found to date with complete cheek teeth rows. Intraspecific variability of this species in dentary shape, tooth morphology, and size difference is highlighted.     

Inhibitory effect of Porphyromonas gingivalis-derived phosphoethanolamine dihydroceramide on acid ceramidase expression in oral squamous cells

The maintenance of diminished acid ceramidase (ASAH1) gene expression leading to the accumulation of antiproliferative intracellular ceramides in oral squamous cell carcinoma (OSCC) has emerged as a prospective oral cancer therapeutic regimen. Our published study demonstrated that the key periodontal pathogen Porphyromonas gingivalis downregulates the expression patterns of ASAH1 mRNA in normal epithelial cells in vitro. Therefore, P. gingivalis may also beneficially diminish the expression of ASAH1 in OSCC. Because a uniquely structured P. gingivalis-derived phosphoethanolamine dihydroceramide (PEDHC) inhibits the proliferation of normal human fibroblasts, this study aimed to test the effect of PEDHC on the survival of human oral squamous OECM-1 cells in vitro. We demonstrated that the P. gingivalis dihydroceramide-null (ΔPG1780) strain upregulates the expression of ASAH1 mRNA and promotes aggressive proliferation and migration of OECM-1 cells compared to the parent P. gingivalis-W83 strain. In addition, the intracellular concentration of ceramides was dramatically elevated in OECM-1 cells exposed to PEDHC in vitro. Furthermore, PEDHC inhibited expression patterns of ASAH1 mRNA as well as some genes associated with degradation of the basement membranes and extracellular matrix, for example, MMP-2, ADAM-17 and IL-6, in OECM-1 cells. Altogether, these data indicated that PEDHC produced by P. gingivalis inhibits acid ceramidase expression, promotes intracellular ceramide accumulation and suppresses the survival and migration of OSCC cells in vitro. Further studies are needed to determine molecular mechanisms of PEDHC-mediated inhibitory effect(s) on OSCC using in vivo models of oral cancer.     

Novel approach to microbiological air monitoring in show caves

Air microbial pollution in touristic areas poses a risk for both the integrity of an ecosystem and human health. Microbiological monitoring together with environmental parameters monitoring allows for the assessment of the impacts and formulation of sound management decisions to protect humans and ecosystems. Four show caves from the Carpathian Mountains were selected for our study. The caves were sampled monthly to obtain an overview of the changes that occur over a yearly cycle. For the microbial monitoring, we used RIDA^®COUNT test plates, while the environmental parameters were monitored with a variety of devices. Second and third generations of microbes extracted from the plates were grown on specific media for the purpose of 16S rRNA and 18S rRNA extraction and taxa identification. The bacterial communities identified in the air samples in the four investigated show caves were dominated by Staphylococcus, while regarding the fungi communities, Penicillium was more likely to occur in the touristic part of the caves and Cladosporium in the non-visited passages. Together with data on number of visitors, number of bats and radon levels we were able understand the impact of tourists on the cave environment and to generate microbiological risk maps for human health. This type of comprehensive study can be used not only to protect the integrity of a touristic area from the impacts caused by the introduction of allochthonous organic matter, but also for the protection of the tourists and guides from potential pathogenic taxa.     

Stochastic population growth in spatially heterogeneous environments: the density-dependent case

Journal of Mathematical Biology - This work is devoted to studying the dynamics of a structured population that is subject to the combined effects of environmental stochasticity, competition for...     

Anaerobic microplate assay for direct microbial conversion of switchgrass and Avicel using <Emphasis Type="Italic">Clostridium thermocellum</Emphasis>

Objective

To develop and prototype a high-throughput microplate assay to assess anaerobic microorganisms and lignocellulosic biomasses in a rapid, cost-effective screen for consolidated bioprocessing potential.

Results

Clostridium thermocellum parent Δhpt strain deconstructed Avicel to cellobiose, glucose, and generated lactic acid, formic acid, acetic acid and ethanol as fermentation products in titers and ratios similar to larger scale fermentations confirming the suitability of a plate-based method for C. thermocellum growth studies. C. thermocellum strain LL1210, with gene deletions in the key central metabolic pathways, produced higher ethanol titers in the Consolidated Bioprocessing (CBP) plate assay for both Avicel and switchgrass fermentations when compared to the Δhpt strain.

Conclusion

A prototype microplate assay system is developed that will facilitate high-throughput bioprospecting for new lignocellulosic biomass types, genetic variants and new microbial strains for bioethanol production.

     

Occludin is overexpressed in Alzheimer's disease and vascular dementia

The tight junctions (TJs) are key players in the control of blood-brain barrier (BBB) properties, the most complex TJs in the vascular system being found in the endothelial cells of brain capillaries. One of the main TJs proteins is occludin, which anchors plasma membranes of neighbour cells and is present in large amounts in the brain endothelia. Previous studies demonstrated that disruption of BBB in various pathological situations associates with changes in occludin expression, and this change could be responsible for malfunction of BBB. Therefore in this study, applying an immunohistochemical approach, we decided to explore the occludin expression in frontal cortex (FC) and basal ganglia in ageing control, Alzheimer's disease (AD), and vascular dementia (VD) brains, as far as all these pathologies associate microangiopathy and disruption of BBB. Strikingly, we found selected neurons, astrocytes and oligodendrocytes expressing occludin, in all cases studied. To estimate the number of occludin-expressing neurons, we applied a stereological approach with random systematic sampling and the unbiased optical fractionator method. We report here a significant increase in ratio of occludin-expressing neurons in FC and basal ganglia regions in both AD and VD as compared to ageing controls. Within the cerebral cortex, occludin was selectively expressed by pyramidal neurons, which are the ones responsible for cognitive processes and affected by AD pathology. Our findings could be important in unravelling new pathogenic pathways in dementia disorders and new functions of occludin and TJs.     

Evidence for hybridization and introgression within a species-rich oak (<Emphasis Type="Italic">Quercus</Emphasis> spp.) community

Background  

Analysis of interspecific gene flow is crucial for the understanding of speciation processes and maintenance of species integrity. Oaks (genus Quercus, Fagaceae) are among the model species for the study of hybridization. Natural co-occurrence of four closely related oak species is a very rare case in the temperate forests of Europe. We used both morphological characters and genetic markers to characterize hybridization in a natural community situated in west-central Romania and which consists of Quercus robur, Q. petraea, Q. pubescen s, and Q. frainetto, respectively.     

Selection on multiple sexual signals in two Central and Eastern European populations of the barn swallow

Variation in intensity and targets of sexual selection on multiple traits has been suggested to play a major role in promoting phenotypic differentiation between populations, although the divergence in selection may depend on year, local conditions or age. In this study, we quantified sexual selection for two putative sexual signals across two Central and East European barn swallow (Hirundo rustica rustica) populations from Czech Republic and Romania over multiple years. We then related these differences in selection to variation in sexual characters among barn swallow populations. Our results show that tail length and ventral coloration vary between populations, sexes, and age classes (first‐time breeders vs. experienced birds). We found that selection on tail length was stronger in first‐time breeders than in experienced birds and in males than in females in the Romanian population, while these differences between age groups and sexes were weak in Czech birds. We suggest that the populational difference in selection on tail length might be related to the differences in breeding conditions. Our results show that ventral coloration is darker (i.e., has lower brightness) in the Romanian than in the Czech population, and in experienced birds and males compared with first‐time breeders and females, respectively. The sexual difference in ventral coloration may suggest sexual selection on this trait, which is supported by the significant directional selection of ventral coloration in first‐time breeding males on laying date. However, after controlling for the confounding effect of wing length and tarsus length, the partial directional selection gradient on this trait turned nonsignificant, suggesting that the advantage of dark ventral coloration in early breeding birds is determined by the correlated traits of body size. These findings show that ventral coloration may be advantageous over the breeding season, but the underlying mechanism of this relationship is not clarified.