The transition to reproductive phase inchenopodium murale L. ecotype 197 - Early flowering long-day plant

Five days of suitable continuous light induced flowering in the majority ofChenopodium murale L. ecotype 197 plants as early as at the phase of the first pair of leaves. At the time of initiation of the 2nd to 4th pairs of leaves the capacity of plants to flower was reduced, the number of flowering plants being significantly lower under the same inductive light treatment. The capacity to flower increased again at the phase of the 5th and the 6th pairs of leaves. Inductive light treatment brought about a marked growth activation of organs present before induction, shoot apex elongation, precocious formation of new leaves and activation of axillary meristems. The course of these changes in plants of different age is demonstrated. The terminal flower developed during 5 short days following inductive light treatment. The paper shows similarities and differences between long-daymutale L. ecotype 197 and short-day C.rubrum L. ecotype 374 grown under practically uniform conditions.     

The changes in the growth pattern of organs ofChenopodium rubrum photoperiodically induced to flowering

The relationship between photoperiodically changed growth of leaves, cotyledons, hypocotyl, roots and flowering has been investigated inChenopodium rubrum. It was found that all the growth characteristics recorded in leaves and cotyledons,i.e. length, area, dry weight and chlorophyll content, were inhibited during three inductive photoperiods (16 h darkness, 8 h light-SD) as compared with control plants grown under continuous illumination. Similarly, the cessation of root elongation and a decrease in root dry weight were observed. On the contrary, the elongation and dry weight of hypocotyl are stimulated by SD. The degree of the effect exerted by SD on the growth of different organs depends both on actual growth stage and the number of SD photoperiods. Increased relative rate of growth of roots and cotyledons was recorded in plants transferred after SD treatment to continuous illumination. However, this rise possesses only transitional character and the relative growth rate of treated plants equals that of control ones afterwards. The above growth changes are discussed as a possible modifying factor of floral differentiation.     

Contribution to the biosynthesis of erythromycin in the presence of propionic acid-1-14C

Опыты деградации с активным эритромицином, полученным путем прибавле ния пропионовой-1-¹⁴Cкислоты в ферментационную среду, показали, что активность наблудается только в эритронолиде, лактоне молекулы эритромицина. Caxapa, дезозамин и кладиноза не были мечены. Активность пропиональдегида VI, которая представляет активность терминальной единицы C₃ эритронолида, в общем отвечала двукратной величине активности единицы C₃, вычисленной на основании активности насыщенного лактона V. Активность метиллевулиновой кислоты VII соответствует теоретической величине, вычисленной для двух активных атомов углерода, что свидетельствует о равноценности единиц C₃ насыщенного лактона. Указанные результаты соответствуют представлению, что в присутствии пропионовой 1-¹⁴C кислоты лактон молекулы эритромицина синтезируется из 1 молекулы пропионила CoA и 6 молекул метилмалонила CoA, с последующим декарбоксилированием.     

Cell differentiation within a yeast colony: metabolic and regulatory parallels with a tumor-affected organism

Nutrient sensing and metabolic reprogramming are crucial for metazoan cell aging and tumor growth. Here, we identify metabolic and regulatory parallels between a layered, multicellular yeast colony and a tumor-affected organism. During development, a yeast colony stratifies into U and L cells occupying the upper and lower colony regions, respectively. U cells activate a unique metabolism controlled by the glutamine-induced TOR pathway, amino acid-sensing systems (SPS and Gcn4p) and signaling from mitochondria with lowered respiration. These systems jointly modulate U cell physiology, which adapts to nutrient limitations and utilize the nutrients released from L cells. Stress-resistant U cells share metabolic pathways and other similar characteristics with tumor cells, including the ability to proliferate. L cells behave similarly to stressed and starving cells, which activate degradative mechanisms to provide nutrients to U cells. Our data suggest a nutrient flow between both cell types, resembling the Cori cycle and glutamine-NH(4)(+) shuttle between tumor and healthy metazoan cells.     

Dexrazoxane provided moderate protection in a catecholamine model of severe cardiotoxicity

Positive effects of dexrazoxane (DEX) in anthracycline cardiotoxicity have been mostly assumed to be associated with its iron-chelating properties. However, this explanation has been recently questioned. Iron plays also an important role in the catecholamine cardiotoxicity. Hence in this study, the influence of DEX on a catecholamine model of acute myocardial infarction (100?mg/kg of isoprenaline by subcutaneous injection) was assessed: (i) the effects of an intravenous dose of 20.4?mg/kg were analyzed after 24?h, (ii) the effects were monitored continuously during the first two hours after drug(s) administration to examine the mechanism(s) of cardioprotection. Additional in vitro experiments on iron chelation/reduction and influence on the Fenton chemistry were performed both with isoprenaline/DEX separately and in their combination. DEX partly decreased the mortality, reduced myocardial calcium overload, histological impairment, and peripheral haemodynamic disturbances 24?h after isoprenaline administration. Continuous 2?h experiments showed that DEX did not influence isoprenaline induced atrioventricular blocks and had little effect on the measured haemodynamic parameters. Its protective effects are probably mediated by inhibition of late myocardial impairment and ventricular fibrillation likely due to inhibition of myocardial calcium overload. Complementary in vitro experiments suggested that iron chelation properties of DEX apparently did not play the major role.     

Light conditions of photoperiodic induction of flowering inChenopodium murale L. ecotype 197 - Early flowering long-day plant

A method of cultivation and effectiveness of different light sources and light regimes in photoperiodic induction of flowering in non-rosette long-day plantChenopodium murale L. ecotype 197 are described. Under the described conditions of cultivation 5 days, of continuous light produced by incandescent bulbs (TESLA 74 3x40 W, red 4.9 μWcm-²nn-¹, far-red 7.4 μWcn-2nm-¹, blue 0.25 μW cm-²nn-¹) induced flowering in the majority of plants.