Terpenes in Pistacia plants: A possible defence role for monoterpenes against gall-forming aphids

A re-investigation of Pistacia vera from southern Italy afforded, in addition to known compounds, two new monoterpenes (+)-9,10-cyclopropylterpine-     

6-Iodoacetamidofluorescein labelling to assess the state of sulphhydril groups after thermal stabilization of isolated nuclei

Summary Isolated nuclei and nuclear matrices, prepared from mouse erythroleukaemia cells, were reacted with the sulphhydryl-specific dye 6-iodoacetamidofluorescein. To determine whether in vitro formation of disulphide bonds might play a role in the nuclear matrix stabilization triggered by exposure of isolated nuclei to the physiological temperature of 37°C, a variety of techniques were employed to assess the state of cysteinyl residues after such an incubation. Both flow cytometry and confocal microscopy quantitative analysis did not reveal major differences in the fluorescence intensity of nuclei incubated at 37°C in comparison with those maintained at 0°C. Confocal scanning laser microscopy revealed that 6-iodoacetamidofluorescein labelled a fibrogranular network in isolated nuclei. The fluorescent pattern of the network was not affected by a 37°C exposure of nuclei. However, such a network was not detectable in isolated nuclear matrices, thus suggesting a possible protein re-arrangement during matrix preparation. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis of fluorescent-labelled nuclear proteins showed no difference between heat-exposed and control samples. We conclude that oxidation of cysteinyl residues is not a major factor leading to the stabilization of nuclei incubated at 37°C.     

Inositides in the nucleus: presence and characterisation of the isozymes of phospholipase β family in NIH 3T3 cells

Previous reports from our laboratories and others have hinted that the nucleus is a site for an autonomous signalling system acting through the activation of the inositol lipid cycle. Among phospholipases (PLC) it has been shown previously that PLCβ₁ is specifically localised in the nucleus as well as at the plasma membrane. Using NIH 3T3 cells, it has been possible to obtain, with two purification strategies, in the presence or in the absence of Nonidet P-40, both intact nuclei still maintaining the outer membrane and nuclei completely stripped of their envelope. In these nuclei, we show that not only PLCβ₁ is present, but also PLCβ₂, PLCβ₃ and PLCβ₄. The more abounding isoform is PLCβ₁ followed by PLCβ₃, PLCβ₂ and PLCβ₄, respectively. All the isoforms are enriched in nuclear preparations free from nuclear envelope and cytoplasmatic debris, indicating that the actual localisation of the PLCβ isozymes is in the inner nuclear compartment.     

Antinociceptive and hypothermic effects of trimethyltin

Trimethyltin (TMT) induced a dose-dependent antinociceptive and hypothermic effect in mice. Antinociception was not attenuated by naloxone but was reversed by atropine. TMT, however, was ineffective in displacing (³H)-QNB binding $\text{in vitro}$ and did not affect (³H)-QNB binding or acetylcholinesterase activity after $\text{in vivo}$ administration. The ethyl ester of nipecotic acid, a specific inhibitor of synaptosomal GABA uptake, exerted a similar antinociceptive effect that could be blocked by atropine. The GABA receptor antagonist bicuculline attenuated antinociception induced by TMT and nipecotic acid ethyl ester but not by morphine or oxotremorine. γ-Vinyl GABA, an irreversible inhibitor of GABA metabolism, prolonged TMT but not morphine-induced antinociception. In contrast, neither the dose-response nor the time course of TMT-induced hypothermia were affected by any of the drugs tested. The findings suggest that the GABAergic system may be involved in TMT induced antinociception; however, the mechanism responsible for the hypothermic effect of TMT is not apparent.     

Ultrastructure and X-Ray Microanalysis of Blood Cells of Ascidia malaca

Ultrastructural studies of Ascidia malaca blood reveal particular cell types, which are characterized by a polymorphism in the organization of the electron dense cytoplasmic material. A new pathway of morula cell differentiation is suggested. X-ray microanalysis shows that vanadium is localized in vacuolated, granular and morular cells. Iron, which is accumulated by this species to a lesser degree than vanadium, is found in vacuolated amebocytes and, together with vanadium, in granular cells. Our results are discussed in the light of the relations between selective metal absorption in blood cells and their specialization and differentiation.     

Nuclear inositide signaling: An appraisal of phospholipase C β1 behavior in myelodysplastic and leukemia cells

Location impinges on function of some of the main players of nuclear inositol lipid cycle. Here we have discussed the behavior of PI-PLCβ1 in myelodysplastic and cultured leukemia cells.The presence of a cryptic deletion of PI-PLCβ1 gene in high-risk MDS patients is accompanied by altered expression of its mRNA in that the overall decrease of mRNA is characterized by a dramatic decrease of the splicing variant 1a, which is cytosolic and partially nuclear, whilst the splicing variant 1b is still highly represented. This suggests that altered expression of nuclear PI-PLCβ1 could be involved in a disregulation of the cell cycle and have also important effects on cell apoptotic pathways.Moreover, in cultured leukemia cells (Felc) it has been reported by means of a proteomic approach that the splicing factor SRp20 interacts with nuclear PI-PLCβ1 and its expression is modulated by this signaling molecule.All in all, it appears more and more evident that nuclear signaling elicited by PI-PLCβ1 is a key event in the control of cell cycle progression.