Changes in ethanol, lactate and malate content in Acer pseudoplatanus cells: effects of fusicoccin and O2 availability

Changes in the contents of ethanol, lactate and malate were determined at different activities of the plasma membrane H⁺ pump [in the presence and absence of fusicoccin (FC)] and at different O₂ availability in cultured cells of Acer pseudoplatanus L. FC induced acidification of the medium under all tested conditions of O₂ availability. At low O₂ concentrations both ethanolic and lactic fermentations occurred, and FC markedly stimulated lactate production but had no effect on ethanol production. There was also a small, stimulating effect of FC on malate production. At high O₂ concentrations no ethanol production was observed and lactate production was reduced. Under these conditions the stimulating effect of FC on lactate production decreased, while that on malate production increased. FC-induced synthesis of lactate and malate is interpreted as depending on the activation of lactate dehydrogenase (EC 1.1.1.27) and phosphoenolpyruvate carboxylase (EC 4.1.1.31) (alkaline pH optima), respectively, due to the alkalinization of the cytoplasmic pH resulting from the stimulation of the H⁺ pump by FC. These results suggest that the balance between the two pH stat systems depends on the availability of O₂.     

TRIDENS X OKLAHOMENSIS (T. FLAVUS X T. STRICTUS), AN INTERSPECIFIC STERILE HYBRID IN THE ERAGROSTEAE (GRAMINEAE)

The incidence of Tridens oklahomensis Feath. with T. flavus (L.) Hitchc. and T. strictus (Nutt.) Nash together with its morphological intermediacy between the latter two species suggests a hybrid origin. Field and laboratory studies conducted over several years provide substantial evidence of an interspecific cross. Tridens oklahomensis appears in generally disturbed habitats, such as roadsides and cleared areas, where the adventive (for this region) T. strictus occurs as overlapping populations with the ubiquitous T. flavus. At no time has the supposed hybrid been recorded solely with one or the other of the two species. On a moisture gradient, T. strictus is found mainly in swales and ditches while T. flavus occurs on the drier and more general upland. The hybrid occurs toward the moist end of gradient, near T. strictus. On this basis it is reasoned that the latter is the pistillate parent. The hybrid is sterile and has no vegetative means of spreading. Under these conditions its presence is limited to chance fertilization in those situations where T. strictus has invaded the range of the more widespread T. flavus.     

Isolation of large peptides derived by cyanogen bromide cleavage of thermolysin using fast protein liquid chromatography (FPLC)

The recently introduced fast protein liquid chromatography (FPLC) system of Pharmacia (Uppsala, Sweden) was employed to isolate rather large peptides derived from thermolysin by selective chemical fragmentation at methionine in positions 120 and 205 of the polypeptide chain of 316 amino acid residues. Thermolysin was cleaved under conditions of limited fragmentation in order to produce, besides fragments 1-120, 121-205 and 206-316, the overlapping fragments 1-205 and 121-316. These polypeptides were separated employing prepacked Mono Q or Mono S columns (quaternary ammonium and sulfonic acid support, respectively). The columns were equilibrated with acetate-7 M urea buffer, pH 5.0 or 6.0, and eluted with a gradient of sodium chloride or acetate. Separations were achieved in 10-20 min and were carried out also at a semi-preparative level (1-3 mg per run). All five protein fragments were isolated in homogeneous form, as judged by amino acid analysis and electrophoresis. Considering that protein fragmentation with cyanogen bromide is the most commonly used procedure to achieve selective chemical fragmentation of a polypeptide chain, these results indicate that FPLC with ionic exchangers can be usefully employed to isolate rather large protein fragments especially suitable for automatic sequence analysis with the sequenator.     

Epidemiological study on the assay of antibodies to anti-TORCH agents and to HBV in a group of mother/child pairs in Palermo

The TORCH group: toxoplasma, rubeola, cytomegalovirus (CMV), herpes virus hominis (HSV) and also the B-virus of hepatitis (HBV) determine congenital malformations in the newborns. For this reason, the Authors leaded an epidemiologic study testing with some antibodies (anti-TORCH and anti-HBV) the serum of groups of mother-newborn of the Obstetrical Clinic of Palermo. This study became manageable because now there are available high specific immunoenzymatic methods, for example ELISA, the passive haemoagglutination and the haemoagglutination-inhibition. In our people, high concentration of rubeola, HSV and CMV and very low concentration of toxoplasma and HBV are shown. The frequency of malformation is related with the subclinical infection. The Authors suggest to extend same investigation at an higher number of pregnant women to prevent these congenital malformations.