Immunocytochemical characterisation of endophytic bacteriaAzospirillum brasilense, Herbaspirillum seropedicae, Burkholderia ambifaria andGluconacetobacter diazotrophicus

In the present work an immunocytochemical characterisation of four endophytic bacterial species has been made by using polyclonal antiserum produced against each of the four bacterial strains previously heated at 60 °C. The aim of this researchsito identify common elements among bacteria associated with their endophytic behaviour. Analysis of extracts of each strain by immunoblotting and ELISA confirmed the presence of proteins from different bacterial strains made up of common epitopes. However, antisaproduced againstHerbaspirillum seropedicae andBurkholderia ambifaria show a high number of bands recognised on each extracts, while antisera againstAzospirillum brasilense andGluconacetobacter diazotrophicus show a low number of bands recognised on each extract. Immunogold labelling showed that epitopes are located both on the cell wall and in the cytoplasm; most likely they could be preursor cell wall proteins synthesized inside the cytoplasm and subsequently transported onto cell wall. Finally, the common bands amog bacterial strains revealed by immunoblotting could play a role as active hydrolases involved in host tissue penetration.     

Presence of a drifting algal bed in the Mar Piccolo basin,Taranto (Ionian Sea,Southern Italy)

A survey is reported of the drifting algal community in Mar Piccolo, a polluted basin subject to sewage outlets. The key role was played by a few key species, mainly floridean red algae.     

Lymphocyte subpopulations in the neonate: identification of an immature subset of OKT8-positive, OKT3-negative cells

T cell subpopulations of lymphocytes from cord blood (CBL) of 24 newborns and from peripheral blood (a-PBL) of 24 healthy adult volunteers were assessed in T cell-enriched, T cell depleted and unseparated lymphocyte fractions by using OKT3, 4, 6, and 8 monoclonal antibodies. The results show that T cell-enriched CBL include adult numbers of OKT3+, OKT4+, OKT6+ and OKT8+ lymphocytes whereas the T cell-depleted fraction consists of a high percentage of OKT8+, OKT3-, non-E rosette-forming cells bearing a PNA receptor. The presence of the PNA receptor and the lack of the OKT3+ antigen strongly support the hypothesis that the subset of OKT8+ cells in cord blood includes immature T lymphocytes that may represent an intermediate stage between thymocytes and mature peripheral T cells.     

Recognition of influenza-infected cells by cytolytic T lymphocyte clones: determinant selection by class I restriction elements

The fine specificity of virus recognition by influenza A/PR8/34(H1N1)-specific cytolytic T lymphocyte (CTL) clones was analyzed with the use of a panel of syngeneic target cells infected with five heterologous influenza A strain viruses. Forty-five H-2 D-end-restricted CTL clones from B10.A(5R) responders (Dd,Ld) demonstrated 14 different patterns of recognition. Many of these clonotypes were able to distinguish between closely related viruses of the same subtype. Such discriminatory capacity, however, was often accompanied by cross-reactivity against a distantly related viral subtype. This supports the contention that virus-specific CTL see different structures than do virus-specific antibodies. A similar analysis of the fine specificity of 60 Db-restricted clones from C57BL/6 responders was performed. The vast majority of this response was composed of clonotypes not observed in the B10.A(5R) response. In addition, the hierarchy of relatedness between the virus strain used for immunization and the various heterologous viruses was different in C57BL/6 and B10.A(5R). In contrast, the D-end-restricted response of Balb/c (Dd,Ld) demonstrated clonotypes similar to those found in B10.A(5R). These data suggest that determinant recognition in an anti-viral CTL response is a function of the H-2 restricting elements, and this is discussed in the context of determinant selection by class I molecules.     

Analysis of brain and myelin lipids by high-performance thin layer chromatography and densitometry

We have developed a simple method involving high-performance thin layer chromatographic separation of total brain and myelin lipids. Only two solvent systems consisting of chloroform: methanol: acetic acid and water at different concentrations were needed. The plate was then stained with three sequential procedures to visualize phospholipids, cholesterol and galactolipids. Densitometric procedure at each step of staining was utilized to obtain quantitative analysis of brain and myelin samples.     

Identification of Tuber magnatum Pico DNA markers by RAPD analysis

Summary Different species of truffle were studied in order to identify species-specific markers. The isolation of two Tuber magnatum Pico markers is reported. One of these could be used as a probe in dot blot hybridization, allowing the development of a rapid test able to identify Tuber magnatum species.     

Effect of propylthiouracil-induced hypothyroidism on cerebral cortex of young and aged rats: Lipid composition of synaptosomes,muscarinic receptor sites,and acetylcholinesterase activity

The effect of hypothyroidism on the lipid composition of synaptosomes, density and affinity of muscarinic receptor sites, and acetylcholinesterase activity in the cerebral cortex of young and aged rats was investigated. The animals were made hypothyroid by adding 0.05% propyl-2-thiouracil to their drinking water for four weeks. This pathological state induced an increase in the relative percentage of sphingomyelin in young rats. In aged rats hypothyroidism induced a decrease of sphingomyelin and glycerophosphocholine and an increase of cholesterol. The effect of hypothyroid state on cerebral cortex resulted in an increase of acethylcholinesterase activity both in young and aged rats and was also reflected in an increase of density of M1-AChRs but only in the former.     

Cytosolic 5′-nucleotidase/nucleoside phosphotransferase: A nucleoside analog activating enzyme?

Nucleoside phosphotransferase acting on inosine and deoxyinosine has been partially purified from cultured Chinese hamster lung fibroblasts (V79). The activity is associated with a cytosolic 5′-nucleotidase acting on IMP and deoxyIMP. The transfer of the phosphate group from IMP to inosine catalyzed by this enzyme was activated by ATP and 2,3-bisphosphoglycerate. Inosine, deoxyinosine, guanosine, deoxyguanosine, and the nucleoside analogs 2′,3′-dideoxyinosine and 8-azaguanosine are substrates, while adenosine and deoxyadenosine are not. IMP, deoxyIMP, GMP, and deoxyGMP are the best phosphate donors. The cytosolic 5′-nucleotidase/phosphotransferase substrate, 8-azaguanosine, was found to be very toxic for cultured fibroblasts (LD₅₀ = 0.32 μM). Mutants resistant to either 8-azaguanosine and the correspondent base 8-azaguanine were isolated and characterized. Our results indicated that the 8-azaguanosine-resistant cells were lacking both cytosolic 5′-nucleotidase and hypoxanthine-guanine phosphoribosyltransferase, while 8-azaguanine resistant cells were lacking only the latter enzyme. Despite this observation, both mutants displayed 8-azaguanosine resistance, thus indicating that cytosolic 5′-nucleotidase is not essential for the activation of this nucleoside analog.     

Effect of glucose starvation on germ-tube production byCandida albicans

By incubating starved and unstarved yeast cells in synthetic media with a pH of 4.5 or 6.7 at 37°C the effect of a 3 hours' glucose starvation on germ-tube production byCandida albicans was evaluated. In addition the endocellular content of total carbohydrates, glycogen, trehalose and proteins after and before the starvation were dosed. The most interesting result was the overcoming of the pH-regulated dimorphism, thanks to the starvation treatment. Infact the starved cultures produced germtubes indifferently in neutral or acid media, whereas the filamentation of the unstarved cultures was more copious in pH 6.7 medium. The endocellular content of trehalose and protein was unchanged, whereas total carbohydrates and glycogen showed a shortage after the 3 hours' glucose starvation. The possible involvements of these metabolic changes in the regulation of dimorphic transition are discussed.