Modifications of erythrocyte membrane hydration induced by organic tin compounds

A study on the effects of selected organic chlorides of tin on the extent of hydration of the lipid bilayer of erythrocyte ghosts from pig blood is presented. The following compounds were used, dibutyltin dichloride (DBT), tributyltin chloride (TBT), diphenyltin dichloride (DPhT) and triphenyltin chloride (TPhT). The degree of membrane hydration was measured by the ATR FTIR technique, which makes it possible to estimate the level of carbonyl and phosphate group hydration in lipids of membranes. Other measurements were made with a fluorescence technique involving a laurdan probe. Tin organic compounds caused dehydration of the lipid bilayer of ghosts in the region of the carbonyl groups. DBT and TBT produced weak dehydration in the region of the phosphate group, whereas DPhT and TPhT increased hydration. The results allow one to determine the location of organotin compounds within a membrane, and show that TBT penetrates the membrane the deepest and DBT the shallowest. Phenyl tin compounds penetrate membranes to an intermediate depth. The results obtained indicate that the destructive properties of the organometallic compounds depend mostly on their effect on hydration of the membrane.     

Genes encoding the photosystem II proteins are under purifying selection: an insight into the early evolution of oxygenic photosynthesis

Photosynthesis Research - The molecular evolution concerns coding sequences (CDSs) of genes and may affect the structure and function of proteins. Non-uniform use of synonymous codons during...     

Ribonuclease and proteinase activities in potato leaves immunized against Phytophthora infestans

Local treatment of potato plants with arachidonic acid caused a repeated increase of ribonuclease and proteinase activities in leaves that were directly sprayed with this inducer. Immunization caused no significant systemic changes in the enzyme activity of other potato leaves. However, leaves above the induction zone in the first days after the challenge were found to have a pronounced ribonuclease activity increase in comparison to that gradually rising with disease development in inoculated leaves from plants that were not induced. The proteolytic activity in the leaves of immunized plants after the challenge was decisively on a lower level than that in the leaves of noninduced plants subjected to inoculation.     

Comparative analysis of phenolic acids and flavonoids in shoot cultures of Eryngium alpinum L.: an endangered and protected species with medicinal value

Plant Cell, Tissue and Organ Culture (PCTOC) - Phenolic acids and flavonoids, important bioactive compounds of polyphenols, play a significant role in plants; their impact, mainly as antioxidants,...     

Cytomorphological and biochemical changes in dwarf pea shoots induced by gibberellic acid

Treatment of 8-day-old pea plants for 15 and 24 hr with gibberellic acid resulted in: 1. 2-3 Fold increase of the cell length. 2. About 20% increase of the nuclei and nucleoli size in meristematic zone of plant shoots. 3. Increase of endomitotic and mitotic synthesis of DNA. 4. Increased ability of the cells to bind [3H]Actinomycin D. 5. Higher rate of RNA synthesis. 6. Increase of the fresh weight of apical parts of the green pea shoots. 7. These results indicated that gibberellic acid accelerates the growth and differentiation of plant cells.     

Synthesis and tumoricidal activity of water soluble porphyrinyl-thymidines and related porphyrins

The new cobalt(II)meso-5,10-di(N-methyl-4-pyridinium)-15,20-di(p-phenylene-5′-O-thymidine)porphyrin suppressed the growth of human malignant melanoma cells (M21-HPB) by 95 percent when applied as 2.5 x 10⁻⁵ M solution in tris for 3 days without exposure to light. It was the most effective of the investigated porphyrinyl-nucleosides.     

Cytoplasmic 3H-arginine polypeptides of Ehrlich ascites tumour cells

Summary Low molecular weight ninhydrin positive peptide fractions of the Ehrlich tumour cell cytoplasm were isolated and characterized. After preliminary gel filtration of the cytoplasm on Sephadex G-25 column, the peptide mixture was fractionated on cationic exchanger SP-Sephadex C-25 column and eluted with increasing pH gradient. Five peaks were obtained. Only the first peak contained sugar component. All five peptides were studied with respect to molecular weight, isoelectric point and electrophoretic homogeneity. The cytoplasm of Ehrlich tumour cells contains one peptide of acidic (pI - 5.0), two slightly basic (pI - 7.7 and pI - 7.7) and two strongly basic nature (pI - 8.7 and pI - 8.9). Molecular weights varied from 8 500 to 18 500 daltons. The origin of these peptides is briefly discussed.