In vitro assessment of grapevine resistance to two populations of phylloxera from Australian vineyards

A perlite-based medium is described for in vitro cocultivation of phylloxera with micropropagated vines. Using this system, as well as cocultivations on excised primary roots, six vine types were screened for resistance to one or two populations of phylloxera (SRU-1 or VWL-1) sourced from different Australian vineyards. When inoculated with VWL-1 phylloxera, V. vinifera cv. Shiraz was rated as susceptible, Ramsey as resistant, Schwarzmann, V. riparia and Börner as highly resistant and V. rotundifolia as immune. When inoculated with SRU-1 phylloxera, both V. vinifera and Schwarzmann were rated as susceptible. The potential use of these in vitro methods for rootstock resistance screening and determination of phylloxera biotypes is discussed. Phylloxera behaviour and root responses observed in vitro are also described.     

Evaluation of helical viscometry for assessing the functional properties of mozzarella cheese

The suitability of helical viscometry for assessing the functional performance of molten mozzarella cheese was evaluated. The effects of sample preparation, test temperature, butteroil addition and frozen storage on four main characteristics of the apparent viscosity/torque profile (where T_i is the initial torque, T_max is the maximum torque , T_m is the gradient of profile, and T_min is the minimum torque) of molten cheese were investigated. T_i and T_max. values had the lowest coefficient of variation. The results of this study indicate that helical viscometry is not suitable for assessing the functional properties of unripened mozzarella cheese, but is suitable for cheese that has matured for at least 2 weeks.     

Bacterial Histamine Production as a Function of Temperature and Time of Incubation

Optimal temperature, lower temperature limit, extent, and rate of histamine production in a tuna fish infusion broth (TFIB) varied for the strains of Proteus morganii, Klebsiella pneumoniae, Hafnia alvei, Citrobacter freundii, and Escherichia coli studied. P. morganii and K. pneumoniae produced large quantities of histamine in a relatively short incubation period (<24 hr) at 15°C, 30°C, and 37°C; production was fastest at 37°C. H. alvei, C. freundii, and E. coli produced toxicologically significant levels of histamine (>2500 nmoles/ml) only at 30°C and 37°C on prolonged incubation (≥48 hr). At 72 hr of incubation, optimal temperature for histamine production was 37°C for E. coli and C freundii; 30°C for P. morganii strain 110SC2, K. pneumoniae, and H. alvei; and 15°C for P. morganii strain JM. The lower temperature limits for production of toxicologically significant levels of histamine in TFIB were 7°C for K. pneumoniae; 15°C for both P. morganii strains; and 30°C for H. alvei, C. freundii, and E. coli.     

用DFT法和氯取代位置预测多氯代呫吨酮的气相热力学性质(英文)

The gas phase thermodynamic properties of 135 polychlorinated xanthones (PCXTs) are calculated using a combination of quantum mechanical computations performed with the Gaussian 03 program at the B3LYP/6-311G** level. It is found that the chlorine substitution pattern strongly influences the thermodynamic properties of the compounds. The thermodynamic properties of congeners with the same number of chlorines also depend on the chlorine substitution pattern, especially for ortho-substituted congeners. PCXT congeners with one phenyl ring fully chlorinated are found to be the least stable among the analogues. The effect of the chlorine substitution pattern is quantitatively studied by considering the number and position of Cl atom substitution (NPCS). The results show that the NPCS model may be used to predict the thermodynamic properties for all 135 PCXT congeners. In addition, the values of molar heat capacities at constant pressure (cp,m) from 200 to 1000 K for PCXT congeners are calculated, and the temperature dependence relation of this parameter is obtained using the least-squares method.