Effect of β-indoleacetic acid,maleic hydrazide,and 2,3,5-triiodobenzoic acid on N,P, K,and Ca accumulation by pea plants

A study was performed on the effect of various concentrations of IAA, 2,3,6-triiodobenzoic acid, and maleic hydrazide, supplied to Richter’s nutrient solution, on growth of pea plants in water cultures. After a 18-day cultivation growth was evaluated and in the plants gathered the content of total N, P, K, and Ca was estimated. Growth of experimental plants (as evaluated from fresh and dry weight) was affected by all three regulators in dependence on the concentration used. It was stimulated by lower concentrations and inhibited by higher, the production of both fresh and dry weight of the root system being stimulated by all IAA concentrations used. The ratio of root dry weight to that of the entire plant was markedly increased after application of IAA and 2,3,5-triiodobenzoic acid, whereas when applying maleic hydrazide it was only slightly increased in comparison with control. Stimulation or inhibition of growth induced by IAA treatment was accompanied by an accordingly increased or decreased accumulation of N, P, K, and Ca. Thus their utilization did not change in comparison with control. On the other hand, both inhibitory and stimulatory effects of 2,3,5-triiodobenzoic acid and maleic hydrazide on growth were associated with a relatively lower accumulation of the elements in question, resulting in an increased utilization. The distribution index of N, P, K, and Ca decreased with increasing concentrations of IAA, 2,3,5-triiodobenzoic acid and maleic hydrazide. Only the highest 2,3,5-triiodobenzoic acid and maleic hydrazide concentrations used brought about a more marked increase in the distribution index of potassium, simultaneously with a marked decrease in the distribution index of calcium.     

The effect of dibutyryl cyclic AMP,dopamine and aminophylline on ganglionic surface potential and transmission

A study has been made of the effect of dibutyryl cyclic AMP, dopamine and aminophylline on the surface potential and transmission in the superior cervical ganglion of the cat. Both dibutyryl cyclic AMP(3.5 mg and 7.0 mg i.a.) and dopamine (2 μg i.a.) induced ganglionic hyperpolarization associated with a partial inhibition of transmission. The ganglionic response to aminophylline (4 mg i.a.) was triphasic, comprising an initial depolarization succeeded by a hyperpolarization and late depolarization. After the administration of smaller doses of aminophylline (1 mg and 2 mg i.a.), in part of the experiments, only ganglionic depolarization was observed. These studies provide indirect evidence for the mediation of dopamine hyperpolarization by cyclic AMP in sympathetic ganglia. The ganglion-depolarizing effect of aminophylline is discussed.     

Use of the isopiestic method to determine the osmotic pressure of concentrated nutrient solutions for the cultivation of osmophilic microorganisms

The isopiestic method was used to determine the osmotic pressure of sucrose, glucose, ethylene glycol, potassium chloride and sodium sulphate solutions used to raise the osmotic pressure of cultivation media. The method is suitable for determining π of concentrated solutions. In solutions with NaCl concentrations of less than 0.1m, the accuracy of the method fell because of the relatively high water surface tension and the low vapour pressure. The osmophilic character ofCandida utilis yeasts adapted to dense recirculated molasses mashes was studied by cultivation on synthetic medium whose osmotic pressure was raised by adding mineral salts and organic substances.     

Über die Veränderung des Geschlechtsverhältnisses der Nachkommenschaft im Zusammenhang mit dem Alter der Blüten beiMelandrium album

V pokusu byl sledován vliv stá?í sam?ích a sami?ích květ? (nejdéle pět dní starých) na poměr pohlaví v potomstvu uMelandrium album Gabcke. Bylo zji?těno, ?e v potomstvu ze sprá?ení sami?ích květ? dva dny starých se pr?kazně zvý?ilo procento pestíkových rostlin. V potomstvech ze sprá?ení sami?ích květ? star?ích ne? dva dny se jevila v zastoupení-samic klesající tendence. Stá?í sam?ích květ? nemělo ?ádný vliv na poměr pohlaví v potomstvu.     

Determination of the periphyton production by means of the glass slide method

Summary By means of the glass slide method a study of the periphyton production was performed in the Sedlice Reservoir (Bohemia, Czechoslovakia) during the period July 30, 1958 – June 8th, 1959.The gravimetric mass analysis of the periphyton rendered at 9 sampling dates in 4–6 weeks intervals results for 4 depths (1, 3, 6, 9 m) including the zone of producers, the transitory zone, zone of consumers as well as the benthic zone.The air-dry weight and the dry weight (105°C) showed almost identical results. The dry weight formed in the average 8,0 % of the wet weight. The following values were calculated on the basis of the literature data: the ash-free dry weight by subtracting 20 % from the dry weight, the N-content as 7 % of the ash-free dry weight and the chlorophyll a content as 1,3 % of the ash-free dry weight.The biomass of the periphyton ranged between 0 and 491 mg/sq. dm of the ash-free dry weight with an average value 127,0. The highest values occurred in the depth of 1 m, the lowest near the bottom.The net production rate ranged between 10 and 1010 mg/sq.m/day of the ash-free dry weight with an average value 213. The highest mean value occurred in the depth of 6 m (280), the lowest in the depth of 9 m (91 mg/sq.m/day). The greatest production rates were found in March at all depths.The population turnover was different in each depth. In the depth of 1 m it equals 69,6 days, in 3 m 53,6 days, in 6 m 45,2 days, in 9 m 90,9 days. As a mean 59,6 = 60 days can be accepted. These are the longest turnover values determined at anyelse periphyton community. In the Sedlice Reservoir the periphyton renewes itself 6 times in the course of the year.All results gained were compared with similar data published by different authors. An attempt of correlation of these production data was undertaken, but no clear and reliable relationships could be detected.

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Zusammenfassung Unter Anwendung der Glassplattenmethode wurde eine Untersuchung der Produktion des Aufwuchses in der Sedlice-Talsperre (Böhmen, Tschechoslowakei) in der Zeit vom 30. Juli 1958 bis 8. Juni 1959 durchgeführt.Die angewendete gravimetrische Globalmethode brachte an 9 Entnahmetagen (in 4–6 Wochen-Intervalen) Ergebnisse für 4 Tiefen (1, 3, 6, 9 m), die die Zone der Produzenten, die Übergangszone, die Zone der Konsumenten sowie die benthische Zone darstellen.Das Lufttrockengewicht und das Trockengewicht bei 105°C ergaben fast identische Ergebnisse. Das Trockengewicht stellte im Durchschnitt 8,0 % des Feuchtgewichtes dar. Die folgenden Werte wurden auf Grund von Literaturangaben ausgerechnet: das aschenfreie Trockengewicht durch die Subtraktion von 20 % vom Trockengewicht, der Stickstoffgehalt als 7 % des aschenfreien Trockengewichtes und der Chlorophyllgehalt als 1,3 % des aschenfreien Trockengewichtes.Die Biomasse des Aufwuchses schwankte zwischen 0 und 491 mg/m² des aschenfreien Trockengewichtes und zeigte den durchschnittlichen Wert 127,0. Die höchsten Werte kamen in der Tiefe 1 m und die niedrigsten in 9 m vor.Die Netto-Produktion des Aufwuchses schwankte zwischen 10 und 1010 mg/m²/Tag aschenfreier Trockensubstanz und zeigte den durchschnittlichen Wert 213,0. Die höchsten Durchschnittswerte waren in der Tiefe 6 m (280) und die niedrigsten in 9 m (91 mg/m²/Tag) zu verzeichnen. Im März fand sich in allen Tiefen die höchste Produktion.Der Erneuerungskoeffizient änderte sich mit der Tiefe. In 1 m betrug er 69,6 Tage, in 3 m 53,6 Tage, in 6 m 45,2 Tage, in 9 m 90,9 Tage und im Durchschnitt 59,6 = 60 Tage. Diese Werte sind als die längsten, die irgendwann im Aufwuchse ermittelt wurden, anzusehen. Das heisst, dass sich der Aufwuchs in der Sedlice-Talsperre nur sechsmal im Jahre erneuert.Alle erzielten Resultate wurden mit ähnlichen Literaturangaben verschiedener Autoren verglichen. Es wurde ein Versuch unternommen, alle verfügbaren Produktionswerte zur Korrelation zu bringen, eine klare Abhängigkeit konnte jedoch nicht festgestellt werden.

     

Study of the biological effects of theophylline on V79 cells: Viability,membrane permeability,and metabolic cooperation

The effect of theophylline, a specific inhibitor of phosphodiesterase, on gap junction-mediated intercellular communication between Chinese hamster V79 cells was examined. It was found that addition of theophylline to coculture of 6-thioguanine-resistant (TG^r) and 6-thioguanine-sensitive (TG^s) V79 cells significantly increased the recovery of TG^r cells. This finding indicates an inhibition of metabolic cooperation of V79 cells by theophylline. Theophylline was tested at concentrations <0.3 mg/ml, which were neither cytotoxic (after short or continuous exposure) nor inhibited the synthesis of DNA, RNA, and proteins. At the tested concentrations, no change was found in the membrane permeability of cells. Theophylline did not increase the incorporation of glucose into the cells.Abbreviations TG 6, thioguanine     

Procyclic trypanosomes recycle glucose catabolites and TCA cycle intermediates to stimulate growth in the presence of physiological amounts of proline

Trypanosoma brucei, a protist responsible for human African trypanosomiasis (sleeping sickness), is transmitted by the tsetse fly where the procyclic forms of the parasite develop in the proline-rich (1–2 mM) and glucose-depleted digestive tract. Proline is essential for the midgut colonization of the parasite in the insect vector, however other carbon sources could be available and used to feed its central metabolism. Here we show that procyclic trypanosomes can consume and metabolize metabolic intermediates, including those excreted from glucose catabolism (succinate, alanine and pyruvate), with the exception of acetate, which is the ultimate end-product excreted by the parasite. Among the tested metabolites, tricarboxylic acid (TCA) cycle intermediates (succinate, malate and α-ketoglutarate) stimulated growth of the parasite in the presence of 2 mM proline. The pathways used for their metabolism were mapped by proton-NMR metabolic profiling and phenotypic analyses of thirteen RNAi and/or null mutants affecting central carbon metabolism. We showed that (i) malate is converted to succinate by both the reducing and oxidative branches of the TCA cycle, which demonstrates that procyclic trypanosomes can use the full TCA cycle, (ii) the enormous rate of α-ketoglutarate consumption (15-times higher than glucose) is possible thanks to the balanced production and consumption of NADH at the substrate level and (iii) α-ketoglutarate is toxic for trypanosomes if not appropriately metabolized as observed for an α-ketoglutarate dehydrogenase null mutant. In addition, epimastigotes produced from procyclics upon overexpression of RBP6 showed a growth defect in the presence of 2 mM proline, which is rescued by α-ketoglutarate, suggesting that physiological amounts of proline are not sufficient per se for the development of trypanosomes in the fly. In conclusion, these data show that trypanosomes can metabolize multiple metabolites, in addition to proline, which allows them to confront challenging environments in the fly.     

Relationship between the physicochemical parameters and biodegradation rate of sulfosuccinic acid ester surfactants

The relationship between the rate of biodegradation of 10 sulfosuccinic acid derivatives by a bacterial consortium and the physicochemical parameters was elucidated by principal component analysis followed by modified nonlinear mapping technique. It was established that the hydrophobicity parameters determined in the presence of ions and the bulkiness of the surfactant molecule exert a considerable impact on the biodegradation rate. Nonlinear mapping technique using the absolute values of principal component loadings explains more precisely the relationship than the common nonlinear mapping does.