Factors that Affect the Content of Cadmium,Nickel, Copper and Zinc in Tissues of the Knee Joint

Osteoarthritis causes the degradation of the articular cartilage and periarticular bones. Trace elements influence the growth, development and condition of the bone tissue. Changes to the mineral composition of the bone tissue can cause degenerative changes and fractures. The aim of the research was to determine the content of cadmium (Cd), nickel (Ni), copper (Cu) and zinc (Zn) in the tibia, the femur and the meniscus in men and women who underwent a knee replacement surgery. Samples were collected from 50 patients, including 36 women and 14 men. The determination of trace elements content were performed by ICP-AES method, using Varian 710-ES. Average concentration in the tissues of the knee joint teeth amounted for cadmium 0.015, nickel 0.60, copper 0.89 and zinc 80.81 mg/kg wet weight. There were statistically significant differences in the content of cadmium, copper and zinc in different parts of the knee joint. There were no statistically significant differences in the content of cadmium, nickel, copper and zinc in women and men in the examined parts of the knee joint. Among the elements tested, copper and nickel showed a high content in the connective tissue (the meniscus) compared to the bone tissue (the tibia and the femur).     

Gene inactivation in the plant pathogen Glomerella cingulata: three strategies for the disruption of the pectin lyase gene pnIA

The feasibility of performing routine transformation-mediated mutagenesis in Glomerella cingulata was analysed by adopting three one-step gene disruption strategies targeted at the pectin lyase gene pnIA. The efficiencies of disruption following transformation with gene replacement- or gene truncation-disruption vectors were compared. To effect replacement-disruption, G. cingulata was transformed with a vector carrying DNA from the pnlA locus in which the majority of the coding sequence had been replaced by the gene for hygromycin B resistance. Two of the five transformants investigated contained an inactivated pnlA gene (pnlA ^– );both also contained ectopically integrated vector sequences. The efficacy of gene disruption by transformation with two gene truncation-disruption vectors was also assessed. Both vectors carried a 5and 3truncated copy of the pnlA coding sequence, adjacent to the gene for hygromycin B resistance. The promoter sequences controlling the selectable marker differed in the two vectors. In one vector the homologous G. cingulata gpdA promoter controlled hygromycin B phosphotransferase expression (homologous truncation vector), whereas in the second vector promoter elements were from the Aspergillus nidulans gpdA gene (heterologous truncation vector). Following transformation with the homologous truncation vector, nine transformants were analysed by Southern hybridisation; no transformants contained a disrupted pnlA gene. Of nineteen heterologous truncation vector transformants, three contained a disrupted pnlA gene; Southern analysis revealed single integrations of vector sequence at pnlA in two of these transformants. pnlA mRNA was not detected by Northern hybridisation in pnlA-transformants. pnlA-transformants failed to produce a PNLA protein with a pI identical to one normally detected in wild-type isolates by silver and activity staining of isoelectric focussing gels. Pathogenesis on Capsicum and apple was unaffected by disruption of the pnlA gene, indicating that the corresponding gene product, PNLA, is not essential for pathogenicity. Gene disruption is a feasible method for selectively mutating defined loci in G. cingulata for functional analysis of the corresponding gene products.     

Biological activity of pentachlorophenol on the digestive gland cells of the freshwater mussel Unio tumidus

Many chlorinated phenols and their derivatives are used extensively as insecticides, fungicides and herbicides by industrial and agricultural users throughout the world. Among these substances, pentachlorophenol (PCP) is a broad-spectrum biocide, which is still used as a wood preservative. In this paper, the digestive gland cells were used to assess the effect of PCP in the range of concentrations 3.75-75 microM (0.01-0.2 ppm) on oxidative DNA damage, fluidity changes and peroxidation activity in the plasma membrane. The toxic property of PCP on DNA strand breakage was studied using the comet assay. The results showed that pentachlorophenol in the range of 37.5-75 microM contributed to these lesions. To demonstrate the changes in the fluidity of plasma membrane we used the spectrofluorimetric method using two fluorescence probes: 1-[4-(trimethylamino)phenyl]-6-phenyl-1,3,5-hexatriene (TMA-DPH) and 12-(9-anthroyloxy) stearic acid (12-AS). It was shown that PC did not influence the surface of plasma membrane but contributed to the increase in the fluidity of the internal region of the lipid bilayer in the range of concentrations 18.75-75 microM (0.05-0.2 ppm). We also examined the effect of PCP on the lipid peroxidation. To imply its peroxidation properties the spectrophotometry method was used to measure the level of malondialdehyde (MDA), one of the endpoints of the peroxidation of polyunsaturated fatty acids. The obtained results showed that PCP in the used doses did not initiate the formation of lipid peroxides. Thus, our investigation indicates that PCP can behave as a prooxidant agent but its action depends on the used doses and parameters chosen for the research.     

Structural analysis of a periplasmic binding protein in the tripartite ATP-independent transporter family reveals a tetrameric assembly that may have a role in ligand transport

Several bacterial solute transport mechanisms involve members of the periplasmic binding protein (PBP) superfamily that bind and deliver ligand to integral membrane transport proteins in the ATP-binding cassette, tripartite tricarboxylate transporter, or tripartite ATP-independent (TRAP) families. PBPs involved in ATP-binding cassette transport systems have been well characterized, but only a few PBPs involved in TRAP transport have been studied. We have measured the thermal stability, determined the oligomerization state by small angle x-ray scattering, and solved the x-ray crystal structure to 1.9 A resolution of a TRAP-PBP (open reading frame tm0322) from the hyperthermophilic bacterium Thermotoga maritima (TM0322). The overall fold of TM0322 is similar to other TRAP transport related PBPs, although the structural similarity of backbone atoms (2.5-3.1 A root mean square deviation) is unusually low for PBPs within the same group. Individual monomers within the tetrameric asymmetric unit of TM0322 exhibit high root mean square deviation (0.9 A) to each other as a consequence of conformational heterogeneity in their binding pockets. The gel filtration elution profile and the small angle x-ray scattering analysis indicate that TM0322 assembles as dimers in solution that in turn assemble into a dimer of dimers in the crystallographic asymmetric unit. Tetramerization has been previously observed in another TRAP-PBP (the Rhodobacter sphaeroides alpha-keto acid-binding protein) where quaternary structure formation is postulated to be an important requisite for the transmembrane transport process.     

NKG2D-RAE-1 receptor-ligand variation does not account for the NK cell defect in nonobese diabetic mice

NK cells from NOD mice induced with poly(I:C) in vivo exhibit low cytotoxicity against a range of target cells, but the genetic mechanisms controlling this defect are yet to be elucidated. Defects in the expression of NKG2D and its ligands, the RAE-1 molecules, have been hypothesized to contribute to the reduced NK function present in NOD mice. In this study, we show that segregation of the NK-mediated killing phenotype did not correlate with the NOD Raet1 haplotype and that the large alterations in NKG2D expression previously reported on NK cells expanded in vitro were not observed in primary, poly(I:C)-elicited NK cells in vivo. Additional studies indicate a complex genetic control of defective NOD NK cells including genes linked to the MHC and possibly those that are associated with an altered cytokine response to the TLR3-agonist poly(I:C).     

YbeA is the m3Psi methyltransferase RlmH that targets nucleotide 1915 in 23S rRNA

Pseudouridines in the stable RNAs of Bacteria are seldom subjected to further modification. There are 11 pseudouridine (Ψ) sites in Escherichia coli rRNA, and further modification is found only at Ψ1915 in 23S rRNA, where the N-3 position of the base becomes methylated. Here, we report the identity of the E. coli methyltransferase that specifically catalyzes methyl group addition to form m³Ψ1915. Analyses of E. coli rRNAs using MALDI mass spectrometry showed that inactivation of the ybeA gene leads to loss of methylation at nucleotide Ψ1915. Methylation is restored by complementing the knockout strain with a plasmid-encoded copy of ybeA. Homologs of the ybeA gene, and thus presumably the ensuing methylation at nucleotide m³Ψ1915, are present in most bacterial lineages but are essentially absent in the Archaea and Eukaryota. Loss of ybeA function in E. coli causes a slight slowing of the growth rate. Phylogenetically, ybeA and its homologs are grouped with other putative S-adenosylmethionine-dependent, SPOUT methyltransferase genes in the Cluster of Orthologous Genes COG1576; ybeA is the first member to be functionally characterized. The YbeA methyltransferase is active as a homodimer and docks comfortably into the ribosomal A site without encroaching into the P site. YbeA makes extensive interface contacts with both the 30S and 50S subunits to align its active site cofactor adjacent to nucleotide Ψ1915. Methylation by YbeA (redesignated RlmH for rRNA large subunit methyltransferase H) possibly functions as a stamp of approval signifying that the 50S subunit has engaged in translational initiation.     

The reproductive phenology of nine species of Rhodophyta in the subtidal region of the Isle of Man

Monthly samples of about 40 separate plants of each species were collected from 1 to 3 m below lowest astronomical tide on Port Erin breakwater, Isle of Man, Irish Sea. In three species growing on rock, Plocamium cartilagineum, Cryptopleura ramosa and Callophyllis laciniata, about 90% of the plants were fertile in late summer but less than 10% in spring although some fertile plants were always present. Delesseria sanguinea and Odonthalia dentata, also epilithic, had a winter sporing season, Odonthalia extending into late spring, and all plants were sterile in summer. Three species growing epiphytically, Palmaria palmata, Membranoptera alata and Phycodrys rubens, reproduced maximally in the first half of the year at the time when the stipes of the host species, Laminaria hyperborea, grow fastest. Only Palmaria had a sterile season, late summer. The encrusting Cruoria pellita showed little seasonality. The first three species, which reproduce mainly when the sea temperature is above average, are in the northern part of their geographical range. The remaining species (apart from Cruoria) reproduce mainly at low temperatures and are in the southern half of their ranges. Male plants appear to be in a minority in all species, presumably because they were manifest for a shorter period than carposporic plants. They appeared first after sterile periods and were absent as sporing declined. Plocamium and to a lesser extent Cryptopleura show an extremely high preponderance of tetrasporophytes in the population. This is attributed to perennation and some factor disallowing the survival of most of the tetraspores.