Brightness of yellow fluorescent protein from coral (zFP538) depends on aggregation

The yellow fluorescent protein from coral (zFP538) forms aggregates in water solutions. According to dynamic light scattering and gel filtration data, the aggregation number is approximately 1000-10000 at pH 8-9 and protein concentration 1 mg/mL. Gel filtration demonstrated that dissociation of the aggregates takes place upon dilution, and the molecular weight of the aggregates decreases with pH. Atomic force microscopy (AFM) and near-field scanning optical microscopy (NSOM) were used to obtain images of zFP538 in the solid state. It was shown that protein films are comprised of fluorescent ellipsoidal granules with a 50-300 nm major axis and a 30-130 nm minor axis. The dependence of zFP538 fluorescence on protein concentration between 1.2 x 10(-)(9) and 5.5 x 10(-)(7) M can be divided in two linear regions with different slopes indicating the existence of at least two different forms of zFP538. The fluorescence of zFP538 decreases with time upon acidification, and the decrease depends on pH and protein concentration. Between pH 3.5 and pH 5.5, relative residual fluorescence is higher for concentrated zFP538 solutions (about 10(-)(6) M) as compared with diluted ones (10(-)(7) M and below). Aggregation makes zFP538 more stable against fluorescence quenching upon acidification: the decrease in zFP538 fluorescence at protein concentration 1 mg/mL is completely reversible, unlike that observed for less concentrated solutions. This phenomenon may be due to the decrease in the freedom of chromophore mobility in zFP538 aggregates.     

Chimeric Agonist of Galanin Receptor GALR2 Reduces Heart Damage in Rats with Streptozotocin-Induced Diabetes

Biochemistry (Moscow) - Neuropeptide galanin and its N-terminal fragments reduce the generation of reactive oxygen species and normalize metabolic and antioxidant states of myocardium in...     

Barnase-barstar high affinity interaction phenomenon as the base for the heterogenous bioluminescence pseudorabies virus' immunoassay

The effective new variant of "sandwich" bioluminescent enzyme immunoassay (BEIA) for the sensitive detection of glycoprotein B (gB) of pseudorabies virus (PrV) was presently developed. The high affinity interaction of barnase-barstar protein pair and photoprotein obelin as bioluminescent marker were for the first time successfully applied to BEIA development. Preliminary the two monoclonal antibodies, 11/5 and 34/2, were raised against gB for ELISA PrV detection. Presently we used the same immuno-"sandwich" principle for BEIA. To do this the two different bioconjugates were elaborated. Recombinant barnase was chemically conjugated with monoclonal anti-PrV's gB IgG, and also barstar was fused in frame to obelin. The characteristics of BEIA method have been compared to ELISA PrV detection. We have shown the proposed here gB-BEIA was 40-fold more sensitive as opposed to gB-ELISA test. The construction might have a broad promise in multiple potential immunological applications.     

Morphological characteristics of cultured fresh and thawed pericardium cells

The need for selection of the optimal material for the manufacturing of cardio-patches can be resolved by the use of cryostored autologous pericardial tissue. This short communication is a concise fragment of a large-scale research and demonstrates only the efficiency of cell culturing before and after pericardial preservation in the low temperature conditions.     

Identification and properties of complexes formed by myeloperoxidase with lipoproteins and ceruloplasmin

The first evidence of multi-component complexes formed by myeloperoxidase (MPO), ceruloplasmin (CP), and very low/low density lipoproteins (VLDL/LDL) obtained by electrophoresis, gel filtration, and photon-correlation spectroscopy (PCS) is presented in this paper. Complexes were observed when isolated MPO, CP, and VLDL/LDL were mixed and/or when MPO was added to the blood plasma. Complex LDL–MPO–CP was detected in 44 of 100 plasma samples taken from patients with atherosclerosis, and 33 of 44 samples also contained the VLDL–MPO–CP complex. MPO concentration in these patients’ plasma exceeded 800 ng/ml. Interaction of MPO with high density lipoproteins (HDL) was not revealed, as well as binding of CP to lipoproteins in the absence of MPO. Adding antibodies against apoB-100 to VLDL–MPO–CP and LDL–MPO–CP complexes results in release of lipoproteins. Using PCS the diameters of complexes under study were evaluated. By comparing concentrations of the components in complexes formed by MPO, CP, and lipoproteins their stoichiometry was assessed as 2VLDL:1MPO:2CP and 1LDL:1MPO:2CP. Lipoproteins affected the inhibition of MPO peroxidase activity by CP. The affinity of lipoproteins to MPO–CP complex was assessed using apparent dissociation constants determined as ～0.3 nM for VLDL and ～0.14 nM for LDL.     

Distinct molecular mechanisms control levels of synaptic F‐actin

Polymerization of filamentous (F)‐actin at the neuronal synapse plays an important role in neuronal function. However, the regulatory mechanisms controlling the levels of synaptic actin remain incompletely understood. Here, I used established pharmacological blockers to acutely disrupt the function of actin polymerization machinery, then quantified their effect on synaptic F‐actin levels. Synaptic F‐actin was modestly decreased by inhibition of Arp2/3‐dependent actin branching. Blockade of formin‐dependent actin elongation resulted in an Arp2/3‐dependent increase in synaptic actin that could be mimicked by limited actin depolymerization. Limited actin depolymerization was also sufficient to reverse a decrease in synaptic F‐actin caused by prolonged blockade of synaptic NMDA‐type glutamate receptors. These results suggest that interplay between different actin polymerization pathways may regulate synaptic actin dynamics.     

Transformation of metals and metal ions by hydrogenases from phototrophic bacteria

The ability of hydrogenases isolated from Thiocapsa roseopersicina and Lamprobacter modestohalophilus to reduce metal ions and oxidize metals has been studied. Hydrogenases from both phototrophic bacteria oxidized metallic Fe, Cd, Zn and Ni into their ionic forms with simultaneous evolution of molecular hydrogen. The metal oxidation rate decreased in the series Zn>Fe>Cd>Ni and depended on the pH. The presence of methyl viologen in the reaction system accelerated this process. T. roseopersicina and L. modestohalophilus cells and their hydrogenases reduced Ni(II), Pt(IV), Pd(II) or Ru(III) to their metallic forms under H₂ atmosphere. These results suggest that metals or metal ions can serve as electron donors or acceptors for hydrogenases from phototrophic bacteria.