A unique DNAse associated with mitogen-induced transformation of rat lymphocytes

A unique DNAse was found, following electrophoretic separation, in rat lymphocytes stimulated with either ConA or pokeweed mitogens. This DNAse was absent or minimal in non-stimulated cells. The enzyme was active on native DNA at neutral pH and was activated by EDTA. A possible biological role is discussed as related to DNA replication.     

Cytochemical approach to the development and behaviour of rat alveolar type II cells in culture

The development and characteristics of rat alveolar type II cells were monitored by using various cytochemical techniques. Polarized light microscopy was found useful for observing live type II cells in culture. Cells progressively lose their birefringent granules starting from 48 h of cells in culture, indicating the disappearance of the phospholipids organized lamellae in the lamellar bodies. Similar results were obtained by using an immunocytochemical approach with antibodies raised against the apoprotein component of rat surfactant. A progressive decrease in immuno-staining corresponded to the disappearance of the lamellar bodies, and birefringence. Changes in lectins binding to the cultured type II cells were also observed. Freshly isolated and one day old cultured cells could bind Macula pomifera (MPA) but not Arachis hypogaea (PA) lectins. The reverse was found in 6-7 days old cultured cells which had the ability to bind PA but not MPA the advantage of using various cytochemical techniques for studying the development of type II cells in culture is being discussed.     

Peptide Modulators of ASIC Channels of the Sea Anemone Urticina aff. coriacea (Cuvier, 1798) from the Sea of Okhotsk

Russian Journal of Marine Biology - A search for biologically active peptides has been performed in an aqueous extract of the sea anemone Urticina aff. coriacea (Cuvier, 1798) (Actiniidae) from the...     

Synthesis,characterization and nociceptive screening of new VV-hemorphin-5 analogues

In the present study, some new analogues of VV-hemorphin-5, modified at position 1 and 7 by the non-proteinogenic and/or natural amino acids followed the structures Xxx-Val-Val-Tyr-Pro-Trp-Thr-Gln-NH₂ and Val-Val-Tyr-Pro-Trp-Thr-Yyy-NH₂, where Xxx is Ile or Aib and Yyy is Lys/Orn/Dap/Dab were synthesized to investigate their potential antinociceptive activities. We report also the redox potentials and the acid/base properties as pKa values of these peptide analogues which were compared toward electrochemical behaviour of tryptophan containing peptides. All analogues showed a short lasting initial antinociceptive effect, however H2 hemorphin analogue is characterized with prolong and strong antinociceptive effect, while the other peptide analogues exerted more variable effects on the visceral nociception depending on the dose or time after the intracerebral injection.     

Clonal differences in the response of dark and light reactions of photosynthesis to elevated atmospheric CO2 in poplar

Two hybrid poplar (Populus) clones (i.e., fast growing clone Beauprè and slow growing clone Robusta) were grown for two years from cuttings at close spacings in open top chambers (OTCs) under ambient (AC) and elevated [EC = AC + 350 μmol(CO2) mol-1] CO2 treatments. For clone Beauprè no down-regulation of photosynthesis was observed. Two years of growing under EC resulted in an increase in quantum yield of photosystem 2 (PS2), steady state irradiance saturated rate of net photosynthesis (P _Nmax), chlorophyll (Chl) content, and ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPC) activity for this clone. We suppose that under non-limiting conditions of nitrogen and phosphorus content the response to EC was by building up light-harvesting complexes of PS2 and increasing photochemical efficiency of PS2. Due to a high rate of the primary reactions of photosynthesis and a high RuBPCO activity the end product of the response to EC was an increase in PNmax and a larger saccharides content. The Robusta clone showed a depression in the primary reactions of photosynthesis under EC. We found a decrease in quantum yield of PS2, Chl and phosphorus contents, and in RuBPCO activity. However, an increase in PNmax, saccharides content and Chl a/b ratio was observed. We speculate (1) that the phosphorus deficiency in combination with an increase in CO2 concentrations may lead to a potential damage of the assimilation apparatus of the primary reactions of photosynthesis and to a decrease in photochemical efficiency of PS2; (2) that the primary target of "down-regulation" takes place at PS2 for irradiances above 150 μmol m-2 s-1. This revised version was published online in September 2006 with corrections to the Cover Date.     

Histochemical studies on the distribution of acid phosphatases in neurones of sensory ganglia; light and electron microscopy

Summary Acid phosphatase activity of rat sensory ganglia was studied by light and electron microscopic histochemistry. Neurones of trigeminal and spinal ganglia showed two characteristic patterns of -glycerophosphatase. Enzymic activity in small neurones appeared as granules, i.e. lysosomes, whereas activity in large neurones appeared as a network of filaments and scattered granules. The network pattern was due to localization of the reaction product in the Golgi apparatus and in association with the rough endoplasmic reticulum. The presence of at least two acid phosphatases was suggested on account of differences in sensitivity between the enzymes in the small and large cells toward several fixatives and inhibitors.