The effect of heavy metal stress on the cell viability and leakage of electrolytes of Avicennia germinans leaf discs was investigated by the tissue tolerance test. Foliar discs were incubated with different Cd2+ or CU2+ concentrations for 24 h; thereafter, the cell membrane stability of the tissue was assayed by the cell viability Evans blue and leakage electrolytes methods. The results indicat...

Two functionalized porphyrins: 5,10,15,20-tetrakis(3,4-dimethoxyphenyl) porphyrin (A) and 5,10,15,20-tetrakis(3-hydroxyphenyl)porphyrin (B) obtained and characterized by us were used as ionophores (I) for preparing PVC-based membrane sensors selective to Ag⁺, Pb2+ and Cu2+. The membranes were prepared using three different plasticizers: (bis(2-ethylhexyl)sebacate (DOS), dioctylphtalate (DOP), o...

Ammonia detection technologies are very important in environment monitoring. However, most existing technologies are complex and expensive, which limit the useful range of real-time application. Here, we propose a highly sensitive and selective optical sensor for detection of ammonia (NH3) based on liquid crystals (LCs). This optical sensor is realized through the competitive binding between am...

The determination of free Zn(2+) ion concentration is a key in the study of environmental systems like river water and soils, due to its impact on bioavailability and toxicity. AGNES (Absence of Gradients and Nernstian Equilibrium Stripping) and DMT (Donnan Membrane Technique) are emerging techniques suited for the determination of free heavy metal concentrations, especially in the case of Zn(2...

Recently we discovered a tobacco protein (designated NtCBP4) that modulates heavy-metal tolerance in transgenic plants. Structurally, NtCBP4 is similar to mammalian cyclic-nucleotide-gated non-selective cation channels containing six putative transmembrane domains, a predicted pore region, a conserved cyclic-nucleotide-binding domain, and a high-affinity calmodulin-binding site that coincides w...

A calcium- and calmodulin-dependent kinase that represents the majority of the myosin heavy chain kinase activity in chicken intestinal brush borders has been highly purified. The purification steps include gel filtration, high performance chromatography on anion and cation exchangers, and affinity chromatography on calmodulin-Sepharose. The purified kinase consists of a single major, apparentl...

Frenkel, A. I. and Korshin, G. V. 2001. Studies of Cu(II) in soil by X-ray absorption spectroscopy. Can. J. Soil Sci. 81: 271–276. Based on original data for copper, this paper evaluates the use and advantages of X-ray absorption fine structure (XAFS) in studies of heavy metals in soils. The structural parameters of the Cu2+ target were quantified for soil exposed to copper and the same soil el...

Staphylococci were isolated from rural and urban populations in Iraq, which were not known to be exposed to either heavy metals or antibiotics. The antibiotic and heavy metal resistance patterns of these strains were analyzed in both mannitol-fermenting and nonfermenting strains. Over 90% of the strains were resistant to at least one of the following antibiotics: penicillin, chloramphenicol, er...

Copper is both an essential micronutrient and a toxic heavy metal for most living cells. The presence of high concentrations of cupric ions in the environment promotes the selection of microorganisms possessing genetic determinants for copper resistance. Several examples of chromosomal and plasmid copper-resistance systems in bacteria have been reported, and the mechanisms of resistance have st...

Extracellular polymeric substances (EPSs) were extracted by high-speed centrifugation at 20,000 G for 30 min from an activated sludge treating municipal wastewater. Each gram of sludge, as measured in volatile suspended solids (VSS), contained 7.3 mg of EPS, including 6.5 mg of protein (EPSp) and 0.8 mg of carbohydrate (EPSc). The EPSp had a mean MW of 2.0 x 105; about 18% of EPSp had MW over 5...