Secretory Expression Of The Glucan Endo-1,3-Beta-D-Glucosidase Gene Of Secale Cereale In Yeast Pichia Pastoris

For survival in cold conditions, many organisms have developed unique adaptive mechanisms based on the synthesis of antifreeze proteins, peptides and glycoproteins that prevent ice formation at negative temperatures. These molecules tend to bind ice crystals and lower the freezing point of the solution without the formation of large crystals. Antifreeze proteins (AFP) were found in almost all types of living organisms, including insects, fungus, yeasts, bacteria and plants. The gene of antifreeze protein - glucan endo-1,3-beta-D-glucosidase (ScGlu-3) from Secale cereale was cloned into shuttle vector pPICZαA. The competent cells of yeast Pichia pastoris GS115 were transformed and the producer strain was obtained, which secreted of ScGlu-3 into the culture medium using 3% methanol as the only carbon source. It was found by western blotting that the maximum accumulation of ScGlu-3 in the culture occurs after 48 hours of fermentation on a medium with methanol. Established that rScGlu-3 precipitates at 50-65% of ammonium sulfate.

Adsorption process and mechanism of heavy metal ions by different components of cells, using yeast (Pichia pastoris) and Cu2+ as biosorption models

The Cu2+ first bound to the outer mannan and finally entered the cytoplasm. During the whole adsorption process, the number of adsorption sites in the outer and middle cell walls was the largest, and then gradually decreased.

ER arrival sites associate with ER exit sites to create bidirectional transport portals

COPI vesicles mediate Golgi-to-ER recycling, but COPI vesicle arrival sites at the ER have been poorly defined. We explored this issue using the yeast Pichia pastoris. ER arrival sites (ERAS) can be visualized by labeling COPI vesicle tethers such as Tip20. Our results place ERAS at the periphery of COPII-labeled ER export sites (ERES). The dynamics of ERES and ERAS are indistinguishable, indicating that these structures are tightly coupled. Displacement or degradation of Tip20 does not alter ERES organization, whereas displacement or degradation of either COPII or COPI components disrupts ERAS organization. We infer that Golgi compartments form at ERES and then produce COPI vesicles to generate ERAS. As a result, ERES and ERAS are functionally linked to create bidirectional transport portals at the ER–Golgi interface. COPI vesicles likely become tethered while they bud, thereby promoting efficient retrograde transport. In mammalian cells, the Tip20 homologue RINT1 associates with ERES, indicating possible conservation of the link between ERES and ERAS.