Cloning and characterization of the crystal protein-encoding gene of Bacillus thuringiensis subsp. yunnanensis.

Molecular cloning and characterization of a novel cry gene, cry32Aa, of Bacillus thuringiensis subsp. yunnanensis was carried out. The Cry32Aa protein was predicted to have a molecular mass of 139.2 kDa and was found to have an unusual 42-amino-acid-long tail at the C terminus. The cry32Aa gene was localized on the 103-MDa plasmid of the organism. Bioassays showed no toxicity against several moths and mosquitoes. However, it exhibited weak toxicity against larvae of the diamondback moth, Plutella xylostella.     

Interferon induction of polyamine-dependent protein kinase activity in Ehrlich ascites tumor cells

Treatment of Ehrlich ascites tumor cell cultures $\text{in}\text{vitro}$ with interferon induces a protein kinase activity that is activated by the polyamines, spermidine and spermine. Putrescine antagonizes the activation. The protein kinase yields a phosphorylated endogenous polypeptide of M_r 68,000–70,000. The polyamine-dependent protein kinase activity cofractionates with a double-stranded RNA-dependent protein kinase activity during affinity chromatography on poly (I) ·poly (C) - agarose or by chromatography on phosphocellulose. The double-stranded RNA-dependent protein kinase also phosphorylates an endogenous polypeptide of M_r 68,000–70,000. Unsuccessful attempts to discriminate between these two protein kinase activities on the bases of their respective capacities to be activated by either double-stranded RNA or spermidine/spermine, suggest that a single protein kinase enzyme may be activated by these strikingly dissimilar modifiers.     

Protein turnover and proteolysis during sporulation ofBacillus subtilis

A two-dimensional electrophoretic method was used to show that protein degradation occurs immediately after the end of exponential growth but that its occurrence is masked in the usual assay methods for a 2-h period and that degradation is apparently nonselective with respect to protein molar mass or charge. The results suggest that considerable reutilization of internal amino acids may occur during sporulation regardless of the size of the external chase. Finally, the levels of intracellular proteinase activities present even at the end of exponential phase growth, as measuredin vitro, are sufficient to account for the maximum rates of protein degradation observedin vivo.     

Biochemical investigations of retinotectal adhesive specificity

The preferential adhesion of chick neural retina cells to surfaces of intact optic tecta has been investigated biochemically. The study uses a collection assay in which single cells from either dorsal or ventral halves of neural retain adhere preferentially to ventral or dorsal halves of optic tecta respectively. The data presented support the following conclusions: (a) The adhesion of ventral retina to dorsal tecta seems to depend on proteins located on ventral retina and on terminal β-N-acetylgalactosamine residues on dorsal tecta. (b) The adhesion of dorsal retina to ventral tecta seems to depend on proteins located on ventral tecta and on terminal β- N-acetylgalactosamine residues on dorsal retina. (c) A double gradient model for retinotectal adhesion along the dorsoventral axis is consistent with the data presented. The model utilizes only two complementary molecules. The molecule suggested to be concentrated dorsally in both retina and tectum seems to require terminal β-N-acetylgalactosamine residues for adhesion. Its activity is not affected by protease. A molecule fitting these qualifications, the ganglioside GM(2), could not be detected in a gradient, but lecithin vesicles containing GM(2) adhered preferentially to ventral tectal surfaces. The second molecule, concentrated ventrally in both retina and tectum, is a protein and seems capable of binding terminal β-N- acetylgalactosamine residues. One enzyme, UDP-galactose:GM(2) galactosyltransferase, has been found to be more concentrated in ventral retina than dorsal, but only by 30 percent.     

Impacts of hydrophobicity and ionicity of phendione-based cobalt(II)/(III) complexes on binding with bovine serum albumin

Abstract

For efficient designing of metallodrugs, it is imperative to analyse the binding affinity of those drugs with drug-carrying serum albumins to comprehend their structure–activity correlation for biomedical applications. Here, cobalt(II) and cobalt(III) complexes comprising three phendione ligands, [Co(phendione)₃]Cl₂ (1) and [Co(phendione)₃]Cl₃ (2), where, phendione = 1,10-phenanthroline-5,6-dione, has been chosen to contrast the impact of their hydrophobicity and ionicity on binding with bovine serum albumin (BSA) through spectrophotometric titrations. The attained hydrophobicity values using octanol/water partition coefficient method manifested that complex 1 is more hydrophobic than complex 2, which could be attributed to lesser charge on its coordination sphere. The interaction of complexes 1 and 2 with BSA using steady state fluorescence studies revealed that these complexes quench the intrinsic fluorescence of BSA through static mechanism, and the extent of quenching and binding parameters are higher for complex 2. Further thermodynamics of BSA-binding studies revealed that complexes 1 and 2 interact with BSA through hydrophobic and hydrogen bonding/van der Waals interactions, respectively. Further, UV–visible absorption, circular dichroism and synchronous fluorescence studies confirmed the occurrence of conformational and microenvironmental changes in BSA upon binding with complexes 1 and 2. Molecular docking studies have also shown that complex 2 has a higher binding affinity towards BSA as compared to complex 1. This sort of modification of ionicity and hydrophobicity of metal complexes for getting desirable binding mode/strength with drug transporting serum albumins will be a promising pathway for designing active and new kind of metallodrugs for various biomedical applications.

Communicated by Ramaswamy H. Sarma