Effect of synthetic cationic peptides on activation of the adenylyl cyclase signaling system by biogenic amines in muscle tissue of molluscs and rats

The hormone-sensitive adenylyl cyclase signaling system (ACS), made of serpentine receptor, heterotrimeric G-protein and enzyme adenylyl cyclase (AC), regulates a wide spectrum of growth and metabolic processes in the cell. Molecular mechanisms of functional coupling of ACS components still remain obscure. We examined the influence of synthetic cationic peptides Ac-Ala-His(Ala)2-His-Ala-NH2 (I), Ac-Ala-His-(Ala)3-His-(Ala)2-His-Ala-NH2 (II), and Ac-(Pro)2-His-(Ala)2-His-(Ala)3-His-(Ala)2-His-Ala-NH2 (III) on the basal AC activity and that stimulated by nonhormonal (NaF) and hormonal reagents (serotonin--molluscs, beta-isoproterenol--rats) in smooth muscles of the freshwater bivalve molluscs Anodonta cygnea and in skeletal muscles of rats. Peptides II and III (the latter more effective) were shown to decrease hormone-stimulated AC activity in both tissues, in a dose-dependent manner. Peptide III strongly reduced NaF stimulating effect to AC, which suggests the involvement of this peptide in the functional coupling of both receptors with G-proteins, and of G-proteins with AC. A correlation was found between the efficacy of peptide action on the functional activity of ACS components and peptide length. As shown by IR-spectroscopy, in water all peptides can form helical structures. However, alpha-helicity of peptides I and II was higher than that of peptide III, which does not conform to a power series in efficacy of these peptides. Thus, it is the length of cationic peptides that plays a key role in hormonal regulation of the functional activity of ACS, especially on the step of receptor-G-protein coupling.     

Dispersibility of Nanocrystalline Cellulose in Organic Solvents

Russian Journal of Bioorganic Chemistry - Aqueous suspensions of nanocrystalline cellulose (NCC) were obtained by sulfuric acid hydrolysis using the standard procedure. Suspensions, films, and...     

Structure of Neuroglobin from Cold-Water Sponge Halisarca dujardinii

Molecular Biology - The iron-containing protein neuroglobin (Ngb) involved in the transport of oxygen is generally considered the precursor of all animal globins. In this report, we studied the...     

The Summerland Disaster.

The reception, admission, and subsequent management of casualties from the Summerland fire are described. A senior member ofthe staff assessed priorities and direceted casualties to different prearranged teams, and a nurse was allocated to each patient to aid continuity of treatment and documentation. Though regular revision and discussion of major accident procedures with all members of the hospital staff and co-ordination with other rescue workers is helpful expensive rehearsals are of limited value in a civilian incident.     

Lysozyme activity of the salivary gland secretion of the medicinal leeches <Emphasis Type="Italic">H. verbana,H. medicinalis</Emphasis>, and <Emphasis Type="Italic">H. orientalis</Emphasis>

Salivary gland secretions of three species of the medicinal leech differ in the level of their lysozyme, and peptidoglycan-lysing activity. Using a synthetic fluorogenic substrate, 4-methylumbelliferyltetra N-acetyl-β-chitotetraoxide, the glycosidase activity (as one of peptidoglycan-lysing activities) of salivary gland secretion of these species of the medicinal leech was quantitatively evaluated in comparison with egg lysozyme. It is suggested that lysozyme activity of the leech secretions is determined not only by 5 isoforms of destabilase-lysozyme, but by some other enzymes which can utilize these substrates including lysozymes other than i-type (invertebrate) lysozymes.     

The concentrations of methaemoglogin, carboxyhaemoglobin and somehaematological parameters in tobacco snuff addicts in Igbo of Nigeria.

Methaemoglobin, carboxyhaemoglobin concentrations and some haematological parameters were studied in fifty tobacco snuff addicts (40 males and 10 females) in some villages of Anambra State, Nigeria. The aim was to investigate possible adverse effects of tobacco snuff in addicts in Igbos of Anambra State. Fifty apparently healthy persons (25 males and 25 females) who do not inhale snuff were used as controls. The age range of tests and control subjects was 25-65 years. The results showed no statistically significant difference when the tests group was compared with the control group. A comparison of the results on the basis of sex, age and period of exposure, showed no significant differences. Blood picture in test and control groups was normocytic and normochromic. The results suggest that tobacco snuff may not have any adverse effect on haemoglobin metabolism and erythropoiesis.     

A theoretical and experimental investigation of the electronic spectra and tautomerization of nucleobases

The electronic structures of all possible tautomers of uracil, thymine, cytosine, adenine and guanine have been carefully examined within the MNDO-MO frame-work. Equilibrium geometries are determined and the relative stabilities are discussed. Allowance for solvent effect on the stabilities is made by assuming a tetrahedral solvent cage with the DNA base occupying its centre. The electronic absorption spectra of the studied DNA bases, in solvents of different polarities are recorded and discussed. Assignments of the observed bands are facilitated using MNDO-CI computations. It is suggested that in solution the DNA bases are in some statistical mixtures of the most stable tautomers, and the Watson-Crick (WC) structure cannot account for the observed spectra alone.