The fission yeast bromodomain protein Bdf2 is required for growth of cells with circular chromosomes

Circular chromosomes have frequently been observed in tumors of mesenchymal origin. In the fission yeast Schizosaccharomyces pombe, deletion of pot1+ results in rapid telomere loss, and the resulting survivors have circular chromosomes. Fission yeast has two bromodomains and extra-terminal (BET) proteins, Bdf1 and Bdf2; both are required for maintaining acetylated histones. Here, we found that bdf2, but not bdf1, was synthetically lethal with pot1. We also obtained a temperature-sensitive bdf2-ts mutant, which can grow at high temperatures but becomes camptothecin sensitive. This suggests that Bdf2 is defective at high temperatures. The cell cycle of the pot1 bdf2-ts mutant was delayed in the G2 and/or M phase at a semi-permissive temperature. Furthermore, a temperature-sensitive mutant of mst1, which encodes histone acetyltransferase, showed a synthetic growth defect with a pot1 disruptant at a semi-permissive temperature. Our results suggest that Bdf2 and Mst1 are required for the growth of cells with circular chromosomes.

Comparative effect of synthetic plant growth regulators for assimilation processes and productivity of cucumber (Cucumis sativus l.). cultivar Nizhynsky

Cucumbers are a common vegetable crop in the world, so increasing its yield is an urgent issue. The effect of Rival and Rist-concentrate on the assimilation processes of cucumber in the phases of three true leaves and flowering in the open ground was studied. It was found that in the phase of three true leaves, pre-sowing treatment of cucumber seeds with Growth-Concentrate increased the value of the area of the cucumber leaf blade by 12.2 % compared to the control indicators. In the flowering phase, Rival and Rist-concentrate showed higher efficiency, stimulating the growth of the area of the cucumber leaf blade by 13.1 % and 16.7 % compared to the control indicators. Studies of the total area of the leaf apparatus of cucumber in the phase of three true leaves showed that the values of the area of the leaf apparatus of cucumber, the seeds of which were treated with Rival and Rist-concentrate exceed control by 34.8 % and 27.8 %, respectively. In the flowering phase, Rival and Growth-concentrate stimulated an increase in the area of the leaf apparatus by 21.4 % and 25.6 % compared to the control indicators. It was found that after measuring the content of chlorophyll in the tissues of cucumber leaves in the phase of three true leaves, the control value for the sum of chlorophyll а and b was 2.32 mg/g of raw mass, chlorophyll a – 1.51 mg/g of raw mass, chlorophyll b is 0.81 mg/g of raw weight. Treatment of cucumber seeds with the drug Rival allowed to increase the content of the sum of chlorophyll a and b to 2.53 mg/g of raw weight. Also, this drug affected the content of chlorophyll b, exceeding the control value by 12.5 %. In this phase, Growth Concentrate did not change the content of photosynthetic pigments in the tissues of cucumber leaves. It was found that the control value for the content of the sum of chlorophyll a and b in the tissues of cucumber leaves in the flowering phase was 2.82 mg/g of raw weight, chlorophyll a – 1.80 mg/g of raw weight, chlorophyll b – 1.01 mg/g raw mass. Treatment of cucumber seeds with Rival increased the amount of chlorophyll a and b to 4 mg/g of raw weight. Also, the drug stimulated the formation of chlorophyll a and b. It was investigated that pre-sowing treatment of cucumber seeds with the drug Rival increases the yield by 22 %, which indicates the effectiveness of this drug. Thus, the synthetic growth regulator Rival can be recommended for use in agricultural practice for pre-sowing treatment of cucumber seeds

Functional characterization of TANGLED1 interaction with PHRAGMOPLAST ORIENTING KINESIN1 during mitosis in Arabidopsis

Cell division requires spatial coordination to properly position the division plane. How division plane positioning contributes to plant growth remains unknown. Two unrelated microtubule binding proteins, TANGLED1 (TAN1) and AUXIN-INDUCED-IN-ROOT-CULTURES9 (AIR9), are together required for normal Arabidopsis growth and division. tan1 air9 double mutants have synthetic growth and division plane orientation defects while single mutants lack obvious defects. We show that the first 132 amino acids of TAN1 (TAN1(1-132)) rescue the tan1 air9 double mutant and localize to the division site during telophase. Loss of both rescue and division-site localization occurred when interaction between TAN1 and PHRAGMOPLAST ORIENTING KINESIN1 (POK1) was disrupted by replacing six amino acid residues with alanines in TAN1(1-132). However, full-length TAN1 with the same alanine substitutions significantly rescued the tan1 air9 double mutant and remained at the division site throughout mitosis, although its accumulation was reduced and phragmoplast positioning defects occurred. POK1 often fails to accumulate at the division site in tan1 air9 mutants, suggesting that both TAN1 and AIR9 stabilize POK1 there. Finally, a mitosis specific promoter driving TAN1 rescued the tan1 air9 double mutant phenotypes indicating that defects seen in the root differentiation zone reflect the loss of mitotic-specific TAN1 activity.

The eIF4E-binding protein Eap1 has similar but independent roles in cell growth and gene expression with the cytoplasmic deadenylase Ccr4

eIF4E-binding proteins (4E-BPs) are translational repressors that compete with eIF4G for binding to eIF4E. Here we investigated the roles of yeast 4E-BPs, Eap1 and Caf20, in cell wall integrity pathway and gene expression. We found that eap1∆ mutation, but not caf20∆ mutation, showed synthetic growth defect with mutation in ROM2 gene encoding Rho1 GEF. The eap1∆ mutation also showed synthetic lethality with mutation in CCR4 gene encoding cytoplasmic deadenylase. Ccr4 functions in degradation of LRG1 mRNA encoding Rho1 GAP. Eap1-Y109A L114A, which could not bind to eIF4E, did not suppress the synthetic lethality of eap1∆ ccr4∆ mutant, suggesting that 4E-binding of Eap1 is important for its function. We also found that eap1∆ mutant showed derepression of stress response gene HSP12. 4E-binding of Eap1 was also required for repression of HSP12 expression. Our results indicate that Eap1 has similar but independent roles in cell growth and gene expression with Ccr4.

The main directions in the implementation of organic agriculture

Measures for the introduction of organic agriculture, along with the use of appropriate techniques in agriculture, imply the rejection of the use of chemical-synthetic growth regulators or hormones; limited, strictly tied to the area, livestock; feeding animals, if possible, with their own feed, minimum purchase of feed and avoiding antibiotics. However, there is currently no way to permanently stop using antibiotics. Therefore, a gradual decrease in doses, frequency and timing of their application is relevant. The work is devoted to the implementation of this direction. A synergistic relationship of gentamicin and tylosin was established with an increase in the efficiency of using the created composite preparation with a decrease in the dose and the possibility of the formation of drug-resistant populations of bacteria - causative agents of animal diseases.