Silicateins identification of the freshwater sponge L. baicalensis

Siliceous spicules of the freshwater Baikal sponge Lubomirskia baicalensis contain several proteins including silicateins. Existences of four different genes of silicatein alpha (alpha1, alpha2, alpha3, alpha4) which are related to silicatein alpha from the sea sponges were found when cDNA library analysis was made. The intron-exon structure of the full-size silicatein alpha1 gene was determined. This gene has total length of 1988 bp and includes 6 introns (1007 bp) and 7 exons (981 bp). With use of mass-spectrometric analysis of the spicule proteins tryptic digest, two silicateins alpha were authentically found.     

Adipokinetic hormone counteracts oxidative stress elicited in insects by hydrogen peroxide: in vivo and in vitro study

The role of adipokinetic hormone (AKH) in counteracting oxidative stress elicited in the insect body is studied in response to exogenously applied hydrogen peroxide, an important metabolite of oxidative processes. In vivo experiments reveal that the injection of hydrogen peroxide (8 µmol) into the haemocoel of the firebug, Pyrrhocoris apterus L. (Heteroptera: Pyrrhocoridae) increases the level of AKH by 2.8‐fold in the central nervous system (CNS) and by 3.8‐fold in the haemolymph. The injection of hydrogen peroxide also increases the mortality of experimental insects, whereas co‐injection of hydrogen peroxide with Pyrap‐AKH (40 pmol) reduces mortality to almost control levels. Importantly, an increase in haemolymph protein carbonyl levels (i.e. an oxidative stress biomarker) elicited by hydrogen peroxide is decreased by 3.6‐fold to control levels when hydrogen peroxide is co‐injected with Pyrap‐AKH. Similar results are obtained using in vitro experiments. Oxidative stress biomarkers such as malondialdehyde and protein carbonyls are significantly enhanced upon exposure of the isolated CNS to hydrogen peroxide in vitro, whereas co‐treatment of the CNS with hydrogen peroxide and Pyrap‐AKH reduces levels significantly. Moreover, a marked decrease in catalase activity compared with controls is recorded when the CNS is incubated with hydrogen peroxide. Incubation of the CNS with hydrogen peroxide and Pyrap‐AKH together curbs the negative effect on catalase activity. Taken together, the results of the present study provide strong support for the recently published data on the feedback regulation between oxidative stressors and AKH action, and implicate AKH in counteracting oxidative stress. The in vitro experiments should facilitate research on the mode of action of AKH in relation to oxidative stress, and could help clarify the key pathways involved in this process.     

Freshwater sponge silicateins: comparison of sequences and exon-intron structure of genes

Siliceous sponge spicules contain silicateins--proteins taking part in biogenic silica precipitation and determination of the spicule morphological features. The exon-intron structure of four silicatein-alpha isoforms: -alpha1,-alpha2, -alpha3 and -alpha4 from endemic baikalian sponge Lubomirskia baicalensis was studied. For eight sponge species, including both cosmopolitan (Spongilla lacustris, Ephydatia muelleri, E. fluviatilis) and Baikal endemic (L. baicalensis, L. incrustans, Baikalospongia intermedia, B. fungiformis, Sw. papyracea) species, seventeen gene fragment sequences of different silicatein isoforms were determined. It was shown that cosmopolitan and endemic Baikalian sponges differ from each other by gene structure (have different length ofintrons). Among Baikalian sponges silicatein-alpha1 has the most variable intron length, and silicatein-alpha4 is the most conservative. Phylogenetic analysis of amino-acid silicatein sequences allow identify different silicatein isoforms, which authentically differ form four clusters on phylogenetic tree. Phylogenetic analysis of exon-intron sequences gives the possibility to separate different sponge species in the clusters.     

Organization of fusicoccin receptor in higher plant plasma membrane: relationship between affinity and molecular mass

Higher plant plasma membranes carry receptors of different affinity for the phytotoxin fusicoccin. Reception of fusicoccin involves proteins belonging to the highly conserved 14-3-3 family, but the complete structure of the fusicoccin receptor (FCR) is unknown. Using radiation inactivation analysis, we estimated the molecular masses of low-affinity and high-affinity FCR at 63 +/- 7 and 130 +/- 15 kD, respectively. The dose dependences of receptor inactivation indicate that microsomal specimens contain "silent" FCRs of 420 +/- 90 kD in amounts commensurate with that of the active FCRs. Both low- and high-affinity FCRs are inactivated by hydrolytic enzymes from the outer surface of the plasma membrane, and impairment of protoplast integrity causes an irreversible transition of the low-affinity binding site into the high-affinity one. A scheme is proposed for the organization of different types of FCR in the plasma membrane, implying that the membrane affinity for fusicoccin reflects the interaction between proteins in the FCR complex.     

New modification of the technic for preserving human brain preparations

The modification suggested is a combination of two methods--one with formalin application, another--without formalin application. At first, 5% solution of formalin is injected into the brain arterial bed, then it is injected with an artificial neoprene resine--latex. The preparation is put into a preserving liquid containing no formalin (a mixture of glycerin--45%, acetous potassium--10%, water--45%) for 1.5--2 months.     

Nanotechnology in Therapeutics: hydrogels and beyond

Nanotechnology in Therapeutics: Current Technology and Applications, Edited by Nicholas A. Peppas, J. Zach Hilt and J. Brock Thomas (Horizon Bioscience, 2007) contains seventeen chapters written by leading specialists in the field of polymeric materials for drug delivery and holds wealth of background as well as state of the art material divided into four sections: "Intelligent Therapeutics and Responsive Delivery Systems for Improved Absorption and Delivery", "Therapeutic Micro- and Nanodevices", "Nanostructured Therapeutic Materials" and "Nanoparticulate Systems in Intelligent Therapy". This newly published volume provides a stimulating read and a good point of reference to researchers wishing to explore the interdisciplinary fusion of nnanotechnology and medical therapeutics. The following gives brief summary and critically reviews the book.     

Singlet oxygen scavenging activity of tocopherol and plastochromanol in Arabidopsis thaliana: relevance to photooxidative stress

In the present study, singlet oxygen (¹O₂) scavenging activity of tocopherol and plastochromanol was examined in tocopherol cyclase‐deficient mutant (vte1) of Arabidopsis thaliana lacking both tocopherol and plastochromanol. It is demonstrated here that suppression of tocopherol and plastochromanol synthesis in chloroplasts isolated from vte1 Arabidopsis plants enhanced ¹O₂ formation under high light illumination as monitored by electron paramagnetic resonance spin‐trapping spectroscopy. The exposure of vte1 Arabidopsis plants to high light resulted in the formation of secondary lipid peroxidation product malondialdehyde as determined by high‐pressure liquid chromatography. Furthermore, it is shown here that the imaging of ultra‐weak photon emission known to reflect oxidation of lipids was unambiguously higher in vte1 Arabidopsis plants. Our results indicate that tocopherol and plastochromanol act as efficient ¹O₂ scavengers and protect effectively lipids against photooxidative damage in Arabidopsis plants.