Location of a mutation resistant to cobalt and nickel in LG IIIR of Neurospora crassa

Location of a mutation resistant to cobalt and nickel in LG IIIR of Neurospora crass

Processing and Localization of Dengue Virus Type 2 Polyprotein Precursor NS3-NS4A-NS4B-NS5

Processing of dengue virus type 2 polyprotein precursor NS3-NS4A-NS4B-NS5 could be mediated by the catalytically active NS3 protease domain and NS2B in trans at the dibasic sites NS3-NS4A and NS4B-NS5. Subcellular localization of the unprocessed precursor NS3-NS4A-NS4B-NS5 showed that it was confined to a distinct subcellular organelle in the cytoplasm, which was distinct from the distribution of the mature NS5

Susceptibility of the Wolfgram Proteins and Stability of 2',3'-Cyclic Nucleotide 3'-Phosphodiesterase of Rat Brain Myelin to Limited Proteolytic Digestion

The susceptibility of proteins in the myelin membrane to proteases was studied. Lyophilized rat brain myelin suspended in water was subjected to controlled proteolytic digestion with pure trypsin (N-tosyl-l-phenylalanine chlo-romethyl ketone treated, 5 units/mg of myelin), and proteins remaining in the pellet were analyzed by sodium dode-cyl sulfate-polyacrylamide gel electrophoresis. Under these conditions, large basic protein (LBP) was completely hydro-lyzed in 5–10 min, proteolipid proteins remained largely intact until 60 min, whereas Wolfgram protein (WP) was progressively degraded from 10 min onward with the simultaneous appearance of a new protein band with a molecular weight of 35K. A similar pattern was obtained on treatment with chymotrypsin or subtilisin. The 35K protein band was shown to be derived from WP by its immunological cross-reactivity with WP antibodies. Western blot analysis showed that 35K protein is the only major breakdown product of WP under these conditions. Treatment with higher concentrations of trypsin (>20 units/mg of myelin) resulted in the degradation of all the myelin proteins. Essentially all the 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP) activity was observed in the myelin pellet after controlled or drastic digestion with trypsin. It is concluded that the major fragment of WP (35K) is located in the hydrophobic milieu of the bilayer, relatively inaccessible to trypsin, whereas a portion (20K) of the WP is exposed to the cytoplasmic side (major dense line), like LBP, and that peptide fragments (< 14K) that remained in the myelin membrane lipid bilayer after trypsin digestion could exhibit CNP activity

Mechanism of nickel resistance in a cobalt-resistant wall-less mutant of <i>Neurospora crassa (fz; sg; os-1)</i>

1117-1122A cobalt-resistant wall-less mutant of N. crassa (Cor-sl) characterized previously was also found to be 3-fold more resistant to nickel when compared to the parent wall-less mutant (W-sl). The Cor-sl strain accumulates relatively lower amounts of nickel when compared to W-sl. Sub-cellular fractionation showed significant quantities of nickel to be associated with nuclear and mitochondrial fractions in both the wall-less mutants. However significant differences were observed in vacuolar fractions of W-sl and Cor-sl strains. Fractionation of cell-free extracts on .Sephadex G-10 column resolved nickel into two peaks, of which the peak II in Cor- sl constituted 70% of nickel, while the same in W-sl was about 30%. A 3-fold increase in histidine content was observed in case of Cor-sl as compared to W-sl strain, suggesting its role in Ni-resistance

Bioremediation of trace cobalt from simulated spent decontamination solutions of nuclear power reactors using E. coli expressing NiCoT genes

International audienc

Bioremediation of toxic metal ions using biomass of <i style="">Aspergillus fumigatus</i> from fermentative waste

139-143Dried, nonliving, granulated biomass of Aspergillus fumigatus from fermentation industry was used for the removal of Cd2+, Co2+, Cu2+ and Ni2+ from solutions. Sorption studies showed sequestration (70-90%) of Cd2+ from solutions (0.1-4 mM). However, with increase in concentration, Cd2+ sorption efficiency decreased due to saturation of the biosorbent. Cu2+ binds most efficiently (72%) to the biosorbent followed by Cd2+ (61%), Co2+ (49%) and Ni2+ (37%). Metal removal from solutions containing a mixture of metal ions (Cd2+, Cu2+, Co2+, and Ni2+), which reflects the features of the polluted wastewaters and industrial effluents, was also efficient (90%) at lower concentrations (0.1 mM each). At higher concentrations (5 mM to 25 mM), Cu2+ removal was predominant (>70%) over other ions. The biosorbent was reusuable up to 5 cycles with a 50% loss of initial Cd2+ binding capacity. However, a significant loss of Cd2+ binding capacity was observed when biosorbent was immobilized in polyvinyl foam. Infrared spectra of the biosorbent preparation showed the involvement of alcohol/amine (OH/NH2) and CH-OH functional groups in metal binding. The present studies suggest that fungal biomass, a waste from fermentative industry, has the potential for removal/recovery of toxic metal ions from aqueous solutions

Supercritical Carbon Dioxide at Smectite Mineral–Water Interfaces: Molecular Dynamics and Adaptive Biasing Force Investigation of CO₂/H₂O Mixtures Nanoconfined in Na-Montmorillonite

The carbon dioxide (CO₂) retention capacity and adsorption/desorption energetics of layered nanoporous oxide materials depend critically on the hydration level and the nature of molecular interactions among H₂O, CO₂, charge-balancing cations, and the oxide/hydroxide layers. Molecular-scale understanding of the structure, dynamics, and interfacial energetics of H₂O/CO₂ binary mixtures confined in the interlayer nanopores is paramount to geological CO₂ storage efforts in clay-rich materials. This Article investigates the effects of supercritical CO₂ (scCO₂) in the hydrated interlayer galleries of the hydrophilic smectite mineral (Na-montmorillonite) under geochemically relevant conditions using classical molecular dynamics simulations and enhanced sampling free energy methods. For the compositions investigated, the interactions among the cations, intercalated fluid species, and the basal surfaces result in structures with H₂O and CO₂ coexisting in a single layer at the center of the interlayer. The water molecules in this central H₂O/CO₂ layer cluster around and hydrate Na⁺ ions desorbed from the basal surfaces, whereas CO₂–CO₂ hydrophobic interactions favor mutual clustering of CO₂ molecules. This arrangement results in dynamic percolation paths that facilitate single file-like anisotropic lateral diffusion of CO₂. The water clusters around the Na⁺ ions act as two-dimensional nanopores for the diffusion of Na⁺ between the basal surfaces and across the central H₂O/CO₂ layer, whereas the CO₂-rich regions are not permeable to Na⁺. The near-surface Na⁺ ions occur in two distinct types of coordination environments with distinct NMR spectral fingerprints. Type-I near-surface Na⁺ ions are coordinated by two basal oxygen atoms and four water molecules, whereas for type-II one of the coordinating water molecules is replaced by a CO₂ molecule. The activation energies for a H₂O and a CO₂ molecule to move out of the first coordination shell of a near-surface Na⁺ are ∼2.75 and ∼0.5 kcal/mol, respectively. The activation barriers for site-hopping of a H₂O molecule within the first coordination shell of near-surface and displaced Na⁺ ions are ∼1.6 kcal/mol whereas those for site-hopping of CO₂ around the near-surface and displaced Na⁺ ions are ∼1.8 and ∼3.5 kcal/mol, respectively. The results provide a detailed picture of the interlayer structure and energetics of diffusional motion of cations and intercalates