Evaluating the potential of a bivalve species from the intertidal zone of the Persian Gulf for biomonitoring of trace elements using a nondestructive analytical method

This study was carried out in order to evaluate the potential of the soft and hard tissues of a bivalve species (Callista umbonella) for biomonitoring of different elements in coastal areas of northern part of the Persian Gulf as well as to assess the possible use of PIXE (Proton Induced X-ray Emission) method in this regard. The bivalve specimens and surficial sediment samples were collected from three sampling sites located on the intertidal zone of Hormozgan Province in August 2014. Concentrations of the elements were determined using the non-destructive method, PIXE. Assessment of total organic matter (TOM) and grain size were also carried out in the sediment samples. Based on the results, of the 17 elements measured in the soft tissues, (Al, Br, Ca, Cl, Cr, Fe, K, Mg, Mn, Na, O, P, S, Si, Sr, Ti and Zn) in the case of P, Fe, Br and O significant differences were observed between the sampling sites. Of the 14 elements measured in the shells (Al, Br, Ca, Cl, Cu, Fe, Mg, Mn, Na, K, O, S, Si and Sr) only in the case of Si significant differences between the sites could be detected and of the 14 elements measured in the surface sediments (Al, Ca, Cl, Cr, Fe, Mg, Mn, Na, Ni, K, O, S, Si and Ti) in the case of Na, Mg, S, Cl, K , Ca, Ti and Fe significant differences were found between the sites. In each of the above cases, order of the elements accumulation was assessed and possible causes of the differences evaluated. In order to classify the elements based on their levels in the sediments, soft tissues and shells the multivariate analyses (principal component analysis and cluster analysis) were used. According to the gained results, C. umbonella can be considered as a potential candidate species for biomonitoring of a number of elements in the coastal area of the Persian Gulf

Hom-Lie color algebra structures

This paper introduces the notion of Hom-Lie color algebra, which is a natural general- ization of Hom-Lie (super)algebras. Hom-Lie color algebras include also as special cases Lie (super) algebras and Lie color algebras. We study the homomorphism relation of Hom-Lie color algebras, and construct new algebras of such kind by a \sigma-twist. Hom-Lie color admissible algebras are also defined and investigated. They are finally classified via G-Hom-associative color algebras, where G is a subgroup of the symmetric group S_3.Comment: 16 page

Duckweed (Lemna minor) as a Model Plant System for the Study of Human Microbial Pathogenesis

BACKGROUND: Plant infection models provide certain advantages over animal models in the study of pathogenesis. However, current plant models face some limitations, e.g., plant and pathogen cannot co-culture in a contained environment. Development of such a plant model is needed to better illustrate host-pathogen interactions. METHODOLOGY/PRINCIPAL FINDINGS: We describe a novel model plant system for the study of human pathogenic bacterial infection on a large scale. This system was initiated by co-cultivation of axenic duckweed (Lemna minor) plants with pathogenic bacteria in 24-well polystyrene cell culture plate. Pathogenesis of bacteria to duckweed was demonstrated with Pseudomonas aeruginosa and Staphylococcus aureus as two model pathogens. P. aeruginosa PAO1 caused severe detriment to duckweed as judged from inhibition to frond multiplication and chlorophyll formation. Using a GFP-marked PAO1 strain, we demonstrated that bacteria colonized on both fronds and roots and formed biofilms. Virulence of PAO1 to duckweed was attenuated in its quorum sensing (QS) mutants and in recombinant strains overexpressing the QS quenching enzymes. RN4220, a virulent strain of S. aureus, caused severe toxicity to duckweed while an avirulent strain showed little effect. Using this system for antimicrobial chemical selection, green tea polyphenols exhibited inhibitory activity against S. aureus virulence. This system was further confirmed to be effective as a pathogenesis model using a number of pathogenic bacterial species. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate that duckweed can be used as a fast, inexpensive and reproducible model plant system for the study of host-pathogen interactions, could serve as an alternative choice for the study of some virulence factors, and could also potentially be used in large-scale screening for the discovery of antimicrobial chemicals