The effect of high hydrostatic pressure on the cell center and microtubules in tissue culture cells

A network of cytoplasmic microtubules in PE cells disassembles at 37 degrees C under 1000 atm pr. in 12 to 14 hours; under 2000 atm pr., the disassembly time is not more than 2 hours. The reconstitution process sets in 20 minutes after pressure dropping to proceed diffusely throughout the cytoplasm. Microtubules attached to the cell center reappear in 45 minutes. The dynamics of microtubular disassembly and reconstitution indicates a complete inactivation of the cell center as a microtubule-organizing center.     

Experimental Justification of Approaches to Developing Pathogenetic Means towards the Prevention and Treatment of Early Postradiation Gastrointestinal Disorders

Biology Bulletin - Experiments on dogs have shown that antagonists of receptor types D2 (domperidone, metoclopramide, dimethpramide), 5-HT3 (ondansetron, palonosetron), and NK1 (aprepitant) impair...     

Electrogenicity at the donor/acceptor sides of cyanobacterial photosystem I

To study electrogenesis the photosystem I particles fromSynechococcus elongatus were incorporated into asolectin liposomes, and fast kinetics of laser flash-induced electric potential difference generation has been measured by a direct electrometric method in proteoliposomes adsorbed on a phospholipid-impregnated collodion film. The photoelectric response has been found to involve three electrogenic stages associated with (i) iron-sulfur center F_x reduction by the primary electron donor P700, (ii) electron transfer between iron-sulfur centers F_x and F_A/F_B, and (iii) reduction of photo-oxidized P700⁺ by reduced cytochromec ₅₅₃. The relative magnitudes of phases (ii) and (iii) comprised about 20% of phase (i).     

Photoelectric effects in bacterial chromatophores. Comparison of spectral and direct electrometric methods

Generation of photoelectric potential in chromatophores of Rhodopseudomonas sphaeroides has been measured (i) spectrophotometrically, using electrochromic shift of carotenoid absorption band or (ii) electrometrically, by means of two electrodes separated by a collodion film covered on one side with chromatophores. A 15 ns laser flash was used to induce a single turnover of photosynthetic reaction centers. It was found that results obtained by both methods are similar in (i) direction of electric vector (the chromatophore interior positive) and (ii) redox titration curves (E_m = 10mV). The magnitudes of the photopotential were about 60 and 25 mV, when monitored with spectral and electrometric techniques, respectively. In both cases, the rise times of the photopotentials were faster than time resolution of the techniques used. Decay of the response of carotenoids was found to be slower than that in the collodion film system. The addition of ubiquinone Q₁₀ into the decane solution of asolectin used to impregnate the collodion film led to slowing down of the decay. The carotenoid response decay could be accelerated by FCCP or o-phenanthroline. In the latter case, the shape of the decay curve coincides with decay of the photopotential measured in the collodion film system. It is suggested that decane extracts secondary ubiquinone from chromatophores attached to the collodion film. Such an unfavorable effect can be strongly decreased by added ubiquinone