Antarctic scallop (Adamussium colbecki) annual growth rate at Terra Nova Bay

Adamussium colbecki is one of the most well-studied Antarctic molluscs. However, information on its growth rate is currently based on estimates from mark and recapture experiments and from growth-ring analyses. This paper provides the first estimates of the growth pattern of this scallop throughout a year, for individuals maintained under both natural field and laboratory conditions. Results show size-related differences in growth rate, both in the field and in aquaria, with scallops in Terra Nova Bay growing faster than those kept in aquaria. Growth performances were lower than those reported in the literature.     

Properties of endogenous β-glucosidase of a Saccharomyces cerevisiae strain isolated from Sicilian musts and wines

Three hundred sixty-one yeast strains (80 of which ascribable to Saccharomyces cerevisiae) were isolated from Sicilian musts and wines with the purpose of looking for β-glucosidase (βG, EC 3.2.1.21) activity. Of these, the AL 41 strain had highest endogenous βG activity and was identified as belonging to the species S. cerevisiae by biochemical and molecular methods. This enzyme was subsequently characterized. It had optimum effect at pH 3.5–4.0, whilst optimum temperature was 20 °C, compatible with typical wine-cellar conditions; it was not inhibited by ethanol, at concentrations of 12–14%, or fructose and glucose. The βG was also characterised in terms of the kinetic parameters K_m (2.55 mM) and V_max (1.71 U mg⁻¹ of protein). Finally, it remained stable for at least 35 days in model solutions of must and wine.     

Properties of endogenous β-glucosidase of a Pichia anomala strain isolated from Sicilian musts and wines

The AL 112 strain, isolated from 361 yeast strains in Sicilian musts and wines, has been identified by biochemical and molecular methods as belonging to Pichia anomala, and your endogenous β-glucosidase (βG, EC 3.2.1.21) subsequently characterised. This strain not only has extremely high specific productivity of βG, but above all shows arabinosidase (Ara, EC 3.2.1.55) activity, essential for aroma enhancement of wine. βG from Al 112 is activated by ethanol at the concentrations typically found in wine; it is not inhibited by fructose, whilst glucose, a non-competitive inhibitor, despite lowering activity, actually protects the enzyme from factors that could damage it. It has an optimum temperature of 20 °C, compatible with typical cellar conditions, and stability in model must-wine and wine solutions ≥40 days.     

Sympatric sister species in rodents are more chromosomally differentiated than allopatric ones: implications for the role of chromosomal rearrangements in speciation

A meta‐analysis approach was used to test for chromosomal speciation in rodents. Forty‐one pairs of sister species, identified in the two most species‐rich rodent families (Cricetidae and Muridae), were used as phylogenetically independent data points, each resulting from a speciation event. About 30% of sister species have an identical karyotype. There was a significant difference in the number of chromosomal differences between sympatric and allopatric sister species, compatible with a direct role of chromosomal rearrangements in speciation.     

GarA is an essential regulator of metabolism in Mycobacterium tuberculosis

Alpha‐ketoglutarate is a key metabolic intermediate at the crossroads of carbon and nitrogen metabolism, whose fate is tightly regulated. In mycobacteria the protein GarA regulates the tricarboxylic acid cycle and glutamate synthesis by direct binding and regulation of three enzymes that use α‐ketoglutarate. GarA, in turn, is thought to be regulated via phosphorylation by protein kinase G and other kinases. We have investigated the requirement for GarA for metabolic regulation during growth in vitro and in macrophages. GarA was found to be essential to Mycobacterium tuberculosis, but dispensable in non‐pathogenic Mycobacterium smegmatis. Disruption of garA caused a distinctive, nutrient‐dependent phenotype, fitting with its proposed role in regulating glutamate metabolism. The data underline the importance of the TCA cycle and the balance with glutamate synthesis in M. tuberculosis and reveal vulnerability to disruption of these pathways.     

Oxidative damage and antioxidant defense system in leaves of Vicia faba major L. cv. Bartom during soil flooding and subsequent drainage

The adaptive reactions of Vicia faba major L. cv. Bartom to 13-27 days soil flooding and to 14 days of drainage following 13-days of soil flooding were studied. Under flooding, oxygen diffusion rate (ODR) in the root zone decreased from 2.28–3.44 to 0.09–0.28?µmol O₂ m^?2 s^?1; the soil redox potential (Eh) decreased from 543 to 70 mV. Upon drainage of flooded soil the ODR and Eh values returned to the control levels. Oxidative damage and defense systems in leaves were assessed by the concentration of thiobarbituric acid reactive substances (TBARs) and by the activities of superoxide dismutase (SOD) and glutathione reductase (GR). Two stages of stress development are described. During the first stage (1–13 days) shoot dry mass did not decrease, the TBARs concentration and SOD activity increased, the GR activity decreased. The second stage (13–27 days) was characterized by a decrease in the TBARs concentration, SOD and GR activities, pigment concentrations and shoot dry mass. Drainage of flooded soil resulted in elevated concentrations of TBARs and also increased the activities of SOD and GR. Increased SOD activity in the first stage of hypoxic stress development and activations of SOD and GR at oxygen re-entry to soil are responsible for tolerance of Vicia faba to hypoxic and post hypoxic stress associated with soil flooding and subsequent drainage.     

The effect of binding divalent metal ions on the conformation of human angiotensin-II in solution as probed by nuclear and electron paramagnetic resonance investigations

The interaction between human angiotensin-II and Mn(II) ions in water solution has been deline-ated by nmr and esr experiments. A pH-dependent binding interaction with the imidazole moiety of His 6 has been shown, ratifying the suggestion that His 6 is involved in intramolecular structuring within the peptide molecule.