Warburg Method Research Articles

New instrumentation in grapevine research: A dual respiration prototype for grape berries and whole bunch. The grape CO2/O2 respiratory quotient revisited

Grape berry respiration is a key process during maturation, since it influences must acidity. In recent literature, there are some reports showing measurements of bunch respiration, as CO2 efflux, from the point of view of the plant C balance. Traditionally, in the late 60 s and 70 s, grape berry respiration, either as CO2 or O2, was measured by slicing grape berries and using the standard Warburg method. Commercially available instruments adequate to measure gas exchange, particularly H2O (transpiration) and CO2 (respiration or photosynthesis), in small fruits (typically apples) are not suitable for a whole bunch or isolated grape berries.In this report, we present a low-cost, closed chamber system where the gases (CO2 and O2) are allowed to accumulate/be consumed, based on the use of sensors from Vaisala (CO2) and SST Sensing (O2), which can monitor respiration in a whole bunch of grape berries, or alternatively in isolated grape berries.Respiration was measured in whole Tempranillo bunches sampled at different phenological stages with the whole bunch respiration prototype. Results showed a decreasing trend of respiration from pea size to maturity (both measured as CO2 efflux and O2 uptake) with an almost constant CO2/O2 respiratory quotient of around 1.3. Data from the old literature postulated an increase in this respiratory quotient when grapes start to ripen. Since the measurement in a whole bunch modifies the relationship between the air volume circulating around the bunch as it grows in size with the phenological stage, we optimized the system by reducing as much as possible the air death volume using an alternative chamber for isolated grape berries. Measurements of Tempranillo grape berries collected at different phenological stages using this new closed system confirmed the decreased respiration trend throughout grape development and ripening period. Even most important, these respiration measurements resulted in a change of the CO2/O2 respiratory quotient from ca. 1.0 before veraison to 1.3 and 1.2 at veraison and maturity, respectively. These data suggest a change in the respired substrate from hexoses to organic acids, putatively mainly malic acid. Finally, a series of respiration measurements as CO2 efflux was made to check any possible physiological effect of cutting the bunch or the grape berry. A very important result of these series of measurements is that the fact of detaching the bunch from the plant or the grape from the bunch did not change the bunch/grape berry respiration rate, at least for several hours.

Culturas visuais e pandemias: aproximações warburguianas aos motivos da Dança da morte e das Vani-tas

Between the 14th and 17th centuries, the life expectancy of the populations of Central Europe was 32 years for men and 27 years for women, the result of high infant mortality, pandemics, wars and lack of food. This continuous presence of death corresponds, in the countries of the northern Alps, to the creation of at least two forms of religious visual culture: in the 15th century, “The dance of the dead”, and in the 17th century, the “vanitas” or, initially, “memento mori ”. Considering the time of the creation of these motifs, the times of the Renaissance and Modernity, it is proposed in this article to test a Warburguian reading of these two motifs, as part of the creation of an “Andachts-raum”, a space for contemplation and self-reflection, understood as a way of externalizing, naming and articulating existential fears to learn to deal with them; in distinction of and addition to a reading that affirms the function of these reasons in educational or moralistic terms or the use of impacting images to, essentially, distress and control people in maintaining the established religious order. This reading is justified by its greater consideration of the religious subject in the Renaissance and the choice of method as it was created specifically for the interpretation of the visual culture of that time. The originality of this exercise lies in the application of Aby M. Warburg's method to religious art. It is expected to contribute to a richer understanding of the creation and role of religious art in the lives of people in general and, in particular, in the times of the Renaissance and the beginning of Modernity.

WAR WORK

In 1941 Fritz Saxl and Rudolf Wittkower of the Warburg Institute organized an exhibition on English Art and the Mediterranean. The photographic exhibition showed the long history of artistic and cultural ties between English art and the classical tradition, employing Aby Warburg's method. The project was an attempt by Saxl, as director, to show the relevance of the Warburg Institute's work in England, the new home of the Library since 1933. Kenneth Clark, director of the National Gallery, actively promoted the work of the Institute, including by supporting the naturalization process for many of the Warburg scholars. The popular belief in the cultural ties between England and Italy fed into the positive reception for the exhibition and into acceptance of the work of the Warburg Institute. The exhibition was published in a large format catalog in 1948, further adding to the popularity of the exhibition with a diverse British public. Although the motivation for the exhibition emerged from political conditions and institutional circumstance, it had a lasting effect on the history of the study of English art and architecture. Wittkower and others turned to research on the classical tradition in English art, even though the method had limited relevance beyond the “neoclassical” period.

NO activation of guanylyl cyclase

Nitric oxide (NO)-sensitive guanylyl-cyclase (GC) is the most important receptor for the signaling molecule NO. Activation of the enzyme is brought about by binding of NO to the prosthetic heme group. By monitoring NO-binding and catalytic activity simultaneously, we show that NO activates GC only if the reaction products of the enzyme are present. NO-binding in the absence of the products did not activate the enzyme, but yielded a nonactivated species with the spectral characteristics of the active form. Conversion of the nonactivated into the activated conformation of the enzyme required the simultaneous presence of NO and the reaction products. Furthermore, the products magnesium/cGMP/pyrophosphate promoted the release of the histidine-iron bond during NO-binding, indicating reciprocal communication of the catalytic and ligand-binding domains. Based on these observations, we present a model that proposes two NO-bound states of the enzyme: an active state formed in the presence of the products and a nonactivated state. The model not only covers the data reported here but also consolidates results from previous studies on NO-binding and dissociation/deactivation of GC.

L-Glutamate biosensor using a novel l-glutamate oxidase and its application to flow injection analysis system

Streptomyces P-106, isolated from soil samples, produced extracellular l-glutamate oxidase in liquid culture. About 10 units enzyme activity per ml medium could be reached after 48–60 h incubation at 28 ° C. A micro-enzyme electrode was prepared by cross linking the purified novel l-glutamate oxidase, produced in our lab, with glutaraldehyde on an aminopropyl-platinized-platinum wire (Φ 0.5 mm). It was used for the determination of l-glutamate in a flow injection analysis system with good performance: accuracy (CV = 0.4%), fast response (< 40 s) and stability (> 30 d). The system showed linear response to the l-glutamate concentration, ranging from 3.0 mg l −1 to 300 mg l −1 (approx. 0.02 mol l −1 to 2.0 mmol l −1). The system was applied to determine the concentration of l-glutamic acid during synthesis. Good correlations were achieved between results obtained with the system and with Warburg method.

Warburg and the Warburgian Tradition of Cultural History

Almost forgotten for decades, above all in Germany, the works of the art historian Aby Warburg (1866-1929) have become topical again in an exceptional way far beyond the confines of his own field. This is due to the specific claim and program of Warburg's scholarship rather than to the output of his factual research. As Jacob Burckhardt's successor and a student of the historian Karl Lamprecht, the Hamburg scholar's entire work is emphatically devoted to cultural-historical [kulturhistorisch] research. The current relevance of the so-called Warburg method is founded precisely upon this interdisciplinary, problem-oriented, and integrative determination of the tasks in his field. Recourse to a scientific tradition of the twenties has made possible a present which discusses the term culture anew, which contemplates a revision of the concept of cultural history, and for which cultural science [Kulturwissenschaft] as model becomes interesting again in terms of self-understanding. Since about 1980, there has been much discussion, particularly in Germany,' about an updated and advanced concept of cultural science, a reflection which has already been embodied in the founding of numerous institutions. A process of integration of the sciences, which was programmatic for Warburg even in his days, is at issue once again, a process which, as Walter Benjamin - who was

Oxygen Consumption Stimulated by δ‐Aminolevulinic Acid in Darkness and during Irradiation of Dark Grown Wheat Leaves

AbstractDark grown wheat leaves (Triticum aestivum L. cv. Starke II Weibull), treated with δ‐aminolevulinic acid in darkness, showed an increased oxygen uptake as measured by a Warburg method. The production of CO2 was also increased in darkness, giving an RQ ≅ 1. The increased respiration was dependent on the treatment time as well as on the concentration of the δ‐aminolevulinic acid. Potassium cyanide suppressed both the normal and the increased respiration. The treatment with δ‐aminolevulinic acid caused accumulation of high amounts of protochlorophyllide. Levulinic acid suppressed the increased oxygen uptake as well as the protochlorophyllide accumulation in δ‐aminolevulinic acid treated leaves. Irradiation rapidly decreased the protochlorophyllide content with a simultaneous increase in oxygen uptake over the dark value. The peak value of the increase in oxygen uptake was reached after about 5 min. The light induced oxygen uptake was dependent on the amount of PChlide present at the onset of irradiation. Also the CO2 production was increased during the first minutes of irradiation but soon fell under the buffer control value. Neither potassium cyanide nor heat denaturation affected the oxygen uptake in light in contrast to the effect on the CO2 production, which was blocked by heat denaturation. The increased oxygen uptake in light initially seems to be a purely photochemical process leading to a release of CO2, which release is probably an enzymatic process induced by the photo‐oxidative decomposition of pigment.

Zur Verwertung unterschiedlicher organischer und anorganischer Verbindungen durch einige Stämme von Bac. cereus var. mycoides (Flügge) : On the Utilization Different Organic and Anorganic Compounds by some Strains of Bac. cereus var. mycoides (Flügge)

In order to investigate the decomposition of 46 organic and anorganic compounds by Bac. mycoides, the behaviour of four strains was tested by means of plate counting technique (after Koch) and the Warburg method. Mostly intensive substances containing protein were decomposed by all strains. Furthermore amino acid, sugar, alcohols, and ammonium salts are used by the bacteria, but there were large differences between strains tested. Urea and nitrates have not been decomposed. Um den Abbau von 46 organischen und anorganischen Verbindungen durch Bac. mycoides zu untersuchen, wurde das Verhalten von vier Stämmen mit Hilfe des Plattentests und der Warburgmethode geprüft. Von allen Stämmen wurden eiweißhaltige Verbindungen am intensivsten abgebaut. Außerdem verwerteten die Bakterien Aminosäuren, Zucker, Alkohole und Ammoniumsalze, wobei jedoch große Unterschiede zwischen den getesteten Stämmen auftraten. Harnstoff und Nitrate wurden nicht abgebaut.

Einfluß von Zeatin auf Atmung und Photosynthese der Mesophyll-Protoplasten vonPetunia

Application of 1 ppm zeatin raises the respiration rate (measured by the Warburg method) of leaf mesophyll protoplasts ofPetunia hybrida by about 50% after 4 h; afterwards there is a rapid decrease. While the rate of respiration in the controls rises after 5 to 6 h, 1 ppm zeatin has a strong inhibitory effect. When the protoplasts are incubated with 0.1 ppm zeatin the rise in the rate is much slower, and after 7 h the rate is 30% higher than in the controls. Abscisic acid (10 ppm) decreases the respiration rate so that after 5 h it is less than half that of the controls. Later on there is a rise as in the controls, perhaps caused by senescence promoting effects of abscisic acid. The photosynthetic rate of the mesophyll protoplasts measured by14CO2 fixation decreases with increasing age of the preparation. The protoplasts previously incubated with zeatin for 1 to 3 h show an increase in photosynthesis: with 0.1 ppm zeatin the14C-fixation rate is higher the longer the hormone could operate. With 1 ppm zeatin we get a typical optimum curve similar to that for respiration. These optimum curves indicate the inhibitory effect of high concentrations of zeatin on respiration and photosynthesis. Aplikaci 1 ppm zeatinu se zvýsi rychlost dýchani (měřeno Warburgovou metodou) protoplastů z mesofylu listůPetunia hybrida po 4 h asi o 50%; pak nasleduje prudký pokles. Zatimeo rychlost dýchani u kontrolnich rostlin stoupa po 5 až 6 h, 1 ppm zeatinu ma silný inhibicni ucinek. Při dýchani u kontrolnich rostlin stoupa po 5 až 6 h, 1 ppm zeatinu ma silný inhibicni ucinek. Při použiti 0.1 ppm zeatinu je vzestup rychlosti, dýchani mnohem pomalejsi a po 7 h je o 30% vyssi než u kontrolnich rostlin. Kyselina abscisova (10 ppm) snižuje rychlost dýchani tak, že po 5 h je rychlost dýchani o polovinu nižsi než v kontrolni variantě. Později nasleduje vzestup, způsobený patrně vlivem kyseliny abscisove podporujici starnuti. Rychlost fotosynthesy protoplastů mesofylu měřena pomoci fixace14CO2 klesa se starnutim preparatu. Protoplasty vystavene působeni zeatinu během 1 až 3 h ukazovaly zvýseni rychlosti fotosynthesy. Při aplikaci 0.1 ppm zeatinu rychlost fixace14CO2 je tim větsi, cim dele mohl hormon působit. Při aplikaci 1 ppm zeatinu byla ziskana typicka optimalni křivka podobna křivce pro dýchani. Tyto optimalni křivky prokazuji inhibicni ucinek zeatinu na dýchani a fotosynthesu.

Manometrische Atmungsmessungen an Protoplasten vonPetunia

Respiration of protoplasts isolated from the leaf mesophyll ofPetunia hybrida was estimated by the Warburg method. The time course of respiration rate shows an initial decrease followed by a prominent increase which is caused by shaking of the protoplast suspension. The absolute respiration rates are low and show an unusual spread, but the temporal form of the curve is always similar to that one shown in Fig. 1.

Über die wirkung des phytochroms beim laubmooskallus II. Sauerstoffmetabolismus und acetylcholinwirkung

The oxygen metabolism is a good parameter for the determination of rapid responses of green moss callus to light. We measured the oxygen uptake with the Warburg method and polarographically with a Clark electrode and the YSI-oxygen monitor. The exposure of dark grown moss callus to red light (5–20 min) induced a rapid increase in O 2 -uptake after switching off the light. The respiration change depends on the exposure duration and the light intensity. During the first 2 or 3 h after irradiation with red light and with red-far red light, the rates of the O 2 -uptake show no differences but after this lag-phase the 2 curves are splitting. The respiration of the red irradiated cells remained higher over a period of 23 h compared to the red — far red irradiated cells. In the latter case the respiration reached the value of the dark control after 20 h. We could reverse the red effect of the rapid respiration change immediately with far red, using an irradiation apparatus with a rhythm of 0.45 s red — far red without a dark-phase. The acetylcholine (ACh) interactions with these light qualities were very complex. ACh was only physiologically active when the cofactor ascorbic acid was present. ATP is an additional cofactor for the ACh action with red — far red induced processes. There are great differences between ACh effects in long time experiments (like our Warburg tests) and in short time ones. ACh had no effect on the oxygen output or uptake when the cells were irradiated with red light, in contrast to the effect occuring with quick alternating red — far red illumination. In this case ACh promotes the oxygen output. This effect is inhibited by eserine. The complex manner of ACh effects is indicated by the results which we got from Warburg experiments. The application of ACh together with the onset of red irradiation has no effect independent of the ATP content of the substrate. We got the opposite results in experiments were we applied the hormone after the red illumination. In this case ACh mimicked a far red effect. ATP in the substrate nullified the ACh-action. We got exactly antagonistic ACh-effects with red — far red light treatments. In this case we had to apply the hormone with the onset of the irradiation. Then ACh mimicked a red light effect but only with ATP as cofactor. The physiological effects of red irradiations in moss callus grown in darkness or in continuous far red light cannot be mimicked by ACh. ACh becomes active after or during the irradiation. Light is necessary for ACh effects. Therefore, we think one cannot consider this hormone as being a special phytochrome hormone.

Studies on the Antioxidative Properties of Trimethylamine Oxide

The antioxidative properties of trimethylamine oxide (TMAO) were investigated by using lard and methyl esters of linseed oil under various oxidative conditions.It was found that TMAO itself had no antioxidative activity. When lard was tested by Active Oxygen method (AOM), the antioxidative activity of natural tocopherols (M-Toc) or butyrated hydroxyanisole (BHA) was promoted remarkably by the addition of TMAO and the same result was also obtained by Weight gain method at 60°C. When methyl esters of linseed oil was tested by Weight gain method to examine the effect of TMAO on M-Toc at 30°C, TMAO showed an pro-oxidative effect at the lower concentration of M-Toc. As the concentration of M-Toc became higher than ca. 0.08%, however, the stability of the substrate increased in proportion to the concentration of TMAO added.The effect of TMAO on the activity of M-Toc was not observed when methyl esters of linseed oil were tested by Warburg method (emulsified with Tween 20, pH 7.0, 37°C) Consequently, it has been recognized that TMAO acted as a potent synergist of antioxidantssuch as M-Toc and BHA under certain conditions.

The protective action of antioxidants and their complex-forming characteristics

Inclusion complexes of 2-(2′-aryl-1,3-indandion-2′-yl)-1,4-naphthohydroquinones with methanol, benzene and ethylbenzene have been prepared and their composition in relation to the substituent on the phenyl nucleus has been determined. The inhibition of oxidation of SKS-30 rubber by these derivatives of 1,4-naphthohydroquinone and their rates of oxidation in methanol by oxygen have been compared by the Warburg method. On the basis of the results so obtained it is suggested that the antioxidant activity of these hydroquinones is not connected with complex formation and that there is no direct relationship between the oxidizability of an antioxidant and its protective effect.

Manometric Study of the Copper-Catalyzed Oxidation of Cysteine

The copper-catalyzed oxidation of cysteine was followed from the consumption of oxygen using the conventional Warburg method and from the formation of hydrogen peroxide using the spectrophotometric method. The rate of oxygen uptake varied with pH and showed a maximum at pH 7.2. Hydrogen peroxide was produced progressively during the oxidation, which indicated the possibility of the successive four equivalent reduction of oxygen via hydrogen peroxide to water. The amounts of oxygen uptake and of hydrogen peroxide formed decreased with the increase of pH. From the peroxide formation and the oxygen consumption, the mode of the utilization of molecular oxygen was discussed. In the low pH region, the two equivalent redox-reaction, in which oxygen is reduced to hydrogen peroxide, may be predominant. As pH increases, hydrogen peroxide formed is utilized for the reoxidation of copper (I) ion, and thereupon the successivefour equivalent redox-reaction becomes predominant.

Influence of hydrogen ion concentration on oxygen consumption in bovine dental pulp.

Oxygen consumption rates in bovine dental pulp were measured by the Warburg method under varied conditions of hydrogen ion concentration. The pH of the suspending fluid ranged from 5.0 to 8.6. The rate of oxygen consumption was not impaired when the pH remained between 6.2 and 7.5. The rate was higher between pH 6.4 and 7.0 and it was greatest at pH 6.6 and 6.8. Respiration was stopped at pH 5.0 and 8.6.

The in vitro O2-consumption of kidney from normal and sublimate intoxicated rats.

The in vitro O2-consumption of kidney slices from normal and sublimate intoxicated rats has been studied by means of Warburg's method. It has been demonstrated previously that the weight of kidneys from sublimate intoxicated rats varies with a positive linear correlation to urine output. the traditional units of Warburg's method, in which O2-consumption is related to dry weight or any known constituent of the investigated tissue, were not suitable for the present experiment. A new unit is therefore introduced, and is defined as microliter O2-consumption in kidneys per g body weight per hour, here called -qo2This unit is reduced with increasing age of the rat, and varies only slightly within an even age group of normal rats. in sublimate intoxicated rats, -qo2 has a close positive linear correlation to the specific gravity of the urine. in a series of rats given 4 mg sublimate per kg body weight, -qo2 was reduced to nearly one half of normal at the time of greatest polyuria. There was no morphological sign...

Investigation of a Wood Curing Waste

The investigation of an industrial waste should be carried out prior to or in conjunction with the design and construction of the waste producing facility. To determine the characteristics and treatability of a waste associated with a new redwood curing process, lab studies were carried out concerning the chemical and biological nature of the waste. It was found that the COD was much higher than the BOD (7,541 mg per 1 vs. 2,260 mg per 1); the organic fraction of the waste was mostly in the suspended and colloidal fraction of the waste (90%); the sample size effected the BOD determination; the Warburg method was best for measuring the BOD; the waste was easily flocculated at either high pH (~11) or low pH (~3) with resultant organic reductions approaching 90%.

The oxygen consumption of rat tissues in the presence of nitrogen, helium or hydrogen

The oxygen consumption rates of Holtzman rat diaphragm, and of slices of liver, brain cortex and kidney cortex were determined for two hours in the presence of 0.21 atm O 2 and 0.79 atm N 2, He or H 2 using the standard Warburg method. The oxygen consumption of rat diaphragms was also studied at increased pressures of He-O 2 or N 2-O 2 and at decreased pressures of O 2 using a pressure microrespirometer. With the exception of young rat liver slices in the first hour and diaphragms in the second hour, there were no significant differences observed in the rates of oxygen consumption of the tissues in the presence of N 2, He or H 2. The oxygen consumption rates of diaphragm were not significantly different in one atm of air or 1 5 atm O 2, and the addition of 3.8 atm N 2 at the same P o 2 did not change the rate. At a Po 2 of 1 atm the oxygen consumption rate was not significantly different in the presence or absence of 4 atm N 2 or He. The observation that small changes in P o 2 in the range from 0.204 to 0.262 atm may produce significant changes in the oxygen consumption rates of the tissues studied has been discussed in relation to interpretation of the results of others. It is concluded that the presence of N 2, He or H 2 does not consistently or significantly affect the rate of oxygen consumption of the four rat tissues studied.

Effects of transition metals and of metal-binding antihypertensive agents on tryptamine oxidase and dopa decarboxylase.

SummaryThe effects of transition and subgroup II metal ions on the activities of crude preparations of tryptamine oxidase and dopa decarboxylase, obtained from fresh guinea pig livers and kidneys, were assayed with the Warburg method. Tryptamine oxidation was accelerated by 10-6M vanadyl ion. Cobalt had a similar but less potent effect. Dopa decarboxylation was inhibited by 10-4M mercuric or cadminum ions. Moreover, 10-4M or lower concentrations of two clinically effective antihypertensive hydrazines also caused acceleration of tryptamine oxidation and inhibition of dopa decarboxylation.

Effect of exercise on the tissue respiration of the brain, skeletal muscle, heart, liver, kidneys, and spleen

The effects of a single sustained physical exercise on the respiration of various tissues of rats were investigated with the aid of Warburg's method. The animals were made to run on a treadmill for 90 min, i.e., until distinct signs of fatigue. The oxygen uptake of skeletal muscles was increased, and that of brain and kidneys reduced, both by a statistically significant margin. Changes in the respiration of liver, heart, and spleen were not statistically significant.