A taxonomic analysis of seed proteins inPinus spp.(Pinaceae)

Seed storage proteins have proved to be a powerful biochemical marker for taxonomic research, but they have not been extensively employed in forest tree studies. In order to improve the understanding of the taxonomy of the genusPinus, total seed proteins of 12 pine species have been analyzed by means of SDS-PAGE (Sodium dodecylsulphate-polyacrylamide gel electrophoresis). The results showed the presence, in the genusPinus, of two main sub-taxa, corresponding to the subgeneraHaploxylon andDiploxylon. Differences and affinities between Mediterranean pine species were found in agreement with classification ofKlaus (1989).     

Membrane molecules involved in adhesion properties of cultured sertoli cells

Membrane components involved in adhesion properties of cultured Sertoli cells have been studied by a combination of immunological and biochemical methods. An antiserum prepared against Sertoli cells induced reversible rounding and detachment of the cells from the culture dishes. The cell surface morphology during detachment was studied by scanning electron microscopy and indirect immunofluorescence. A Triton soluble fraction of crude membrane preparations inhibited the antibody-induced detachment. The antibodies recognized a restricted number of membrane glycoproteins [detectable as prominent bands on Sodium dodecylsulphate polyacrilamide gel electrophoresis (SDS-PAGE), M_r 170, 140, 80, and 48K] both in the Triton soluble fraction of crude membrane preparation and on intact Sertoli cells. The data suggest that the molecules involved in adhesion properties of cultured Sertoli cells are integral membrane glycoproteins exposing antigenic determinants at the cell surface.     

HMG proteins released from the chromatin following incubation of mammalian nuclei with ethidium bromide

The low-molecular-mass high-mobility group (HMG) chromosomal proteins, namely HMG-14, HMG-17, and HMG-I, which have been found in several proliferating tissues, are released following incubation of nuclei isolated from young rat thymus and from human placenta in a low ionic strength medium containing the intercalating agent ethidium bromide. The amount of HMG proteins released is drug concentration-dependent, but at very high concentrations (20-40 mM) other low- and high-molecular-mass proteins, and even histones, are released. These results suggest a very weak interaction of the HMG proteins with DNA, so that they can be easily detached from the chromatin as a consequence of the interaction of DNA with the intercalating agent.     

The diagonal band of Broca is involved in the pressor pathway activated by noradrenaline microinjected into the periaqueductal gray area of rats

AimsThe dorsal periaqueductal gray area (dPAG) is involved in cardiovascular modulation. Previously, we reported that noradrenaline (NA) microinjection into the dPAG caused a pressor response that was mediated by vasopressin release into the circulation. However, the neuronal pathway that mediates this response is as yet unknown. There is evidence that chemical stimulation of the diagonal band of Broca (dbB) also causes a pressor response mediated by systemic vasopressin release. In the present study, we evaluated the participation of the dbB in the pressor response caused by NA microinjection into the dPAG as well as the existence of neural connections between these areas.Main methodsWith the above goal, we verified the effect of the pharmacological ablation of the dbB on the cardiovascular response to NA microinjection into the dPAG of unanesthetized rats. In addition, we microinjected the neuronal tracer biotinylated-dextran-amine (BDA) into the dPAG and looked for efferent projections from the dPAG to the dbB.Key findingsThe pharmacologically reversible ablation of the dbB with local microinjection of CoCl₂ significantly reduced the pressor response caused by NA microinjection (15 nmol/50 nL) into the dPAG. In addition, BDA microinjection into the dPAG labeled axons in the dbB, pointing to the existence of direct connections between these areas.SignificanceThe present results indicate that synapses within the dbB are involved in the pressor pathway activated by NA microinjection into the dPAG and direct neural projection from the dPAG to the dbB may constitute the neuroanatomic substrate for this pressor pathway.     

Modeling the energetics of 100-m running by using speed curves of world champions.

The present study aims to assess energy demand and supply in 100-m sprint running. A mathematical model was used in which supply has two components, aerobic and anaerobic, and demand has three components, energy required to move forward (C), energy required to overcome air resistance (Caero), and energy required to change kinetic energy (Ckin). Supply and demand were equated by using assumed efficiency of converting metabolic to external work. The mathematical model uses instantaneous velocities registered by the 1997 International Association of Athletics Federations world champions at 100 m in men and women. Supply and demand components obtained in the male champion were (in J/kg) aerobic 30 (5%), anaerobic 607 (95%), C 400 (63%), Caero 83 (13%), Ckin 154 (24%). Comparatively, a model that uses the average velocity of the male and female 100-m champions overestimates Ckin by 37 and 44%, respectively, and underestimates Caero by 14%. We argued that such a model is not appropriate because Ckin and Caero are nonlinear functions of velocity. Neither height nor body mass seems to have any advantage in the energetics of sprint running.     

Ulteriori indagini sul rapporto tra nichel e acidi malico e malonico in Alyssum

Abstract

Further contribution on the relationship between nickel and malic and malonic acids in Alyssum.—Further research has been carried out on extracts of leaves and seeds of A. bertolonii Desv., grown on serpentine and normal garden soil, in order to investigate the nature of the nickel compounds present in this plant. On the purified extracts, obtained with water and formic acid, malic and malonic acids have been determined through gas-chromatography of the trimethyl-sililderivatives; Ni, Ca, Mg and K have been analysed by atomic absorption spectrophotometry.

Both malic and malonic acids are present in the leaves of the plants collected on serpentine and therefore rich in nickel, whilst they are present only in small amounts in the plants grown in garden soil. Seeds contain mainly high levels of malic acid. Remarkable amounts of malic acid, related to a high nickel content, have been observed also in the leaves of another nickel accumulator in the genus Alyssum, i.e. A. serpyllifolium Desf. ssp. lusitanicum Dudley et P. Silva, endemic of Portugal serpentines.     

Morphological and biological characterization of cell line developed from bovine <Emphasis Type="Italic">Echinococcus granulosus</Emphasis>

The taeniid tapeworm Echinococcus granulosus is the causative agent of echinococcal disease, a major zoonosis with worldwide distribution. Several efforts to establish an in vitro model of E. granulosus have been undertaken; however, many of them have been designed for Echinococcus multilocularis. In the present study, we have described and characterized a stable cell line obtained from E. granulosus bovine protoscoleces maintained 3 yr in vitro. Growth characterization, morphology by light, fluorescent and electronic microscopy, and karyotyping were carried out. Cell culture origin was confirmed by immunofluorescent detection of AgB4 antigen and by PCR for the mitochondrial cytochrome c-oxidase subunit 1 (DCO1) gene. Cells seeded in agarose biphasic culture resembled a cystic structure, similar to the one formed in secondary hosts. This cell line could be a useful tool to research equinococcal behavior, allowing additional physiological and pharmacological studies, such as the effect of growth factors, nutrients, and antiparasitic drugs on cell viability and growth and on cyst formation.