Organization of the vimentin system and its spatial relationship to the microtubule complex during the division of mammalian cells growing attached and in suspension

We have used immunofluorescence staining with antibodies that detect vimentin, tubulin and the centrioles to compare the distributions of these respective antigens during the division of several suspension and attached cultured cells. Our observations demonstrate that 1) from distinct interphase organizations in suspension and attached cells, the vimentin system consistently rearranges with the onset of mitosis into a filamentous cage-like structure enclosing the spindle, 2) during cytokinesis, the polar centrosomes relocalize near the midbody in suspension cells while they remain at the pole opposite to it in attached cells, and 3) the vimentin cage is disintegrated and aggregated on each side of the midbody during cytokinesis in lymphoid cells but may be retained in other suspension cells.     

Resistance of pear psylla (Cacopsylla pyri L.; Hom., Psyllidae) to deltamethrin and synergism with piperonyl butoxide

Abstract: Topical application bioassays, conducted on French populations of Cacopsylla pyri , showed resistance rates to deltamethrin ranging from 31-fold at the adult stage to 135-fold at the last larval stage. Synergism studies between deltamethrin and piperonyl butoxide (PBO), applied either topically or by tarsal contact with PBO, showed (i) that the rates of synergism were more than 10-fold in all the populations and that they could increase to a thousand-fold in some populations, (ii) that the synergistic effect was present to a similar extent at both the larval and adult stages, (iii) that there was no correlation between the synergistic effect and the resistance rates, and (iv) that no correlation was observed between the dates of collection and the rates of synergism. The results makes it impossible to determine whether resistance to deltamethrin is of genetic origin or results only from the induction of monooxygenases by allelochemical substances present in the food ingested by the species.     

Evaluation of Fourier-transform infrared spectroscopy for data capture in predictive microbiology

Chemical changes in the medium, induced by the fermentative species Lactobacillus plantarum and Lactobacillus brevis and by the enzymatic action of a proteolytic, spoilage species, Yarrowia lipolytica, were analysed using Fourier-transform i.r. spectroscopy (FTIR). Changes in the absorbance data over time could be modelled using one of the more current predictive, mathematical models of microbial growth, such as the Gompertz equation. Moreover, a linear correlation between FTIR data (expressed as absorbance of some selected peaks) and viability data (expressed as log₁₀ c.f.u./g or ml) was observed during the fermentation process, both for L. plantarum and L. brevis.