Analysis of the effect of industrial effluent on pigments, proteins, nucleic acids, and the 2,6-dichlorophenol indophenol Hill reaction of rice seedlings

The effect of an industrial effluent on cellular macromolecular composition and indophenol photochemical activity of isolated chloroplasts of rice (Orvza sativa L. C. V. Mushoori) seedlings have been investigated. Each experiment consisted of two parts. One was the effect of various concentrations and the other was the time-dependent changes induced by the undiluted effluent. The total pigments, proteins, and nucleic acids of rice seedlings declined with an increase in effluent concentration and the time of incubation. The loss in contents of macromolecules like deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and protein was relatively more marked in the root than in the shoot. RNA and chlorophyll (Chl) contents of the seedlings were found most susceptible to effluent stress. Loss in Hill reaction activity measured as photoreduction of 2,6-dichlorophenol indophenol (DCPIP) of isolated chloroplasts could be correlated in a general way with the loss of pigments, proteins and nucleic acids. Diphenyl carbazide- and Mn2+-induced restoration of loss in DCPIP photoreduction suggests that the damage of oxygen evolving systems is the initial site of action of the effluent.

Titrimetric determination of ascorbic acid with 2,6-dichlorophenol indophenol in commercial liquid diets

The titrimetric determination of ascorbic acid in the presence of a variety of potentially physically and chemically interfering species in commercial liquid diets is presented. The titrant and indicator was a solution of 2,6-dichlorophenol indophenol. Iron(II), copper(II), cysteine, glutathione, sulfite, and tin(II) do not interfere.

False negative hyperglucosuria test-strip reactions in laboratory mice

Inhibition of a variety of commercial test strips for hyperglucosuria was experienced in laboratory mice. All mouse strains tested were found to have sufficiently high levels of ascorbic acid to cause inhibition, and male levels were higher than those of females. A regime to obtain optimum detection of positive results is discussed.

[Macroscopic fluctuations in aqueous solutions of proteins and other substances as a possible consequence of cosmo-geophysical factors]

Synchronous measurements of macroscopic fluctuations (MF) in Pushchino, Simferopol, Alma-Ata and Pojakonda (Moscow University Biological Station on the White Sea) show a similarity between the low frequency components of macroscopic fluctuations (trends) after shifting the latter by the time interval corresponding to the difference in longitude. The MF amplitude is shown to be essentially smaller in the North polar circle, as compared with that in the middle latitude. "Signals" presenting reproducible specific sequences of macroscopic fluctuations were found. It is suggested that synchronism and probably the very existence of macroscopic fluctuations are caused by some cosmic-geophysical factors.

Identification of the factor responsible for autogenous bleaching of glycollate oxidase

Autogenous bleaching of glycollate oxidase (glycollate:oxygen oxidore-ductase, EC 1.1.3.1) is characterized by a loss of absorption due to enzyme-bound FMN and the presence of a lag in the catalytic assay. The extent of bleaching varies with different preparations. The following evidence indicates that bleaching is due to the presence of sulfite in the enzyme preparation which forms a reversible complex (EFMN + Y = EFMN . Y, Y = sulfite) with enzyme-bound FMN. Both EFMN . Y and authentic enzyme-sulfite complex exhibit similar spectral and catalytic properties. At pH 7.0 both complexes are decomposed by agents (2,6-dichlorophenolindophenol, H2O2) which cause sulfite oxidation. In the absence of such agents the complexes are extremely stable at pH 7.0 even during extensive dialysis. A pronounced decrease in complex stability is observed at pH 9.0 and 25 degrees C. Both sulfite and Y are readily removed by dialysis under these conditions. At lower temperatures both complexes exhibit an increase in stability at pH 9.0. Reversible association-dissociation is observed with EFMN . Y and EFMN . SO3 at pH 9.0, when the temperature is varied between 25 and 0 degrees C. The supernatant obtained after heat denaturation of EFMN . Y causes bleaching when mixed with EFMN, indicating that Y is present in the heat extract. A stable Bunte salt is formed by reacting sulfite with 4,4'-dithiodipyridine. Reaction of the latter with the heat extract yields a product with spectral and chromatographic properties identical to the authentic Bunte salt, indicating that the heat extract contains sulfite.

Purification of an NADH-(dichlorophenol-indophenol) oxidoreductase from Bacillus stearothermophilus

An NADH-(dichlorophenol-indophenol) oxidoreductase was purified 104-fold and in 25% overall yield from the thermophilic bacterium Bacillus stearothermophilus, strain PH24. After solubilization in 2M-NaCl at 70 degrees C, the enzyme was purified by ion-exchange and hydroxyapatite chromatography, followed by affinity chromatography on immobilized Cibacron Blue 3GA. The purified enzyme had a mol.wt. of 43 000 and had an absorption spectrum characteristic of flavoprotein. The enzyme activity was enhanced by FMN and by CN-. The enzyme was inhibited by EDTA and by rho-chloromercuribenzoic acid.

[Macroscopic fluctuations--a general property of aqueous solutions of different proteins and other substances. Statistical spectral analysis of macroscopic fluctuations]

When studying enzymic activities in successively chosen portions of solutions of pyruvatekinase, hexokinase, lactatedehydrogenase, alkaline phosphatase, acetylcholinesterase and trypsin fast macroscopic fluctuations were revealed. These fluctuations were found earlier in protein preparations of the actomyosin complex and creatinkinase and described as "conformation fluctuations". Similar macroscopic fluctuations were also revealed when measuring the rate of reaction between ascorbic acid and dichlorphenolindophenol (DCAPI). The spectra of macroscopic fluctuations in solutions of different proteins and ascorbic acid+DCAPI are similar to each other in principle. This gives grounds to consider the ability towards macroscopic fluctuations to be a common property of solutions of different substances.

A method for quantitation of vitamin B2 by using an enzyme (producing vitamin B2-aldehyde) from Schizophyllum commune

A method for enzymatic determination of riboflavin was developed by enzymatic reduction of 2,6-dichlorophenolindophenol using a vitamin B2-aldehyde-forming enzyme prepared from Schizophyllum commune. The enzymatic method enabled us to determine riboflavin in a mixture containing riboflavin, FMN and FAD without separation of riboflavin. Moreover, the total amount of flavins in the mixture was shown to be determined by the enzyme in the presence of phosphatase.

[Establishment of the site of electron transport chain disruption in mutant Chlamydomonas chloroplasts with an inactive photosystem 2]

It has been shown in the studies of 6 strains of non-synthesizing Chlamydomonas reinhardi mutants with a damaged electron-transport chain (ETC) in the region of the Photosystem 2 (PS 2) that the damage is localized on the oxidizing side of PS 2. The ESR studies of the mutants have shown that signal 2 is absent in all the mutants, the width of signal 1 in some mutants is lower than in the control, which is, probably, concerned with the differences in the reaction centre structures. The ETC region from electron inlet from the donor--diphenylcarbaside to P700 is capable of functioning. It is suggested that in all the mutants studied the complex responsible for photodissociation of water is damaged.

Cyanide insensitive iron superoxide dismutase in Euglena gracilis. Comparison of the reliabilities of different test systems for superoxide dismutases

Two proteins (P1 and P2, with weights of 57,500 and 27,500 respectively) were isolated from Euglena gracilis. Both proteins show cyanide-insensitive superoxide dismutase activity in the "classical" superoxide dismutase assay, using xanthine-xanthine oxidase as O2.- generator. If O2.- is generated chemically (autoxidation of reduced anthraquinone), photochemically (illuminated riboflavine) or pulse radiolytically, only protein P1 but not P2 shows SOD activity. Protein P1 contains 1 g atom (determined: 0.82) iron (no Mn or Cu) per mole protein and may thus be defined as iron-superoxide dismutase. Protein P2, showing the spectral properties of a flavoprotein, exhibits the activities of ferredoxin-NADP-oxidoreductase and "diaphorase". The cyanide-insensitive SOD-activity of this Diaphorase" in the xanthine oxidase-assay for superoxide dismutase makes this classical and commonly used test unreliable for assay cyanide insensitive SOD activities. The existence of the "prokaryote-type" of superoxide dismutase (Fe-SOD) in Euglena gracilis is exceptional for an eukaryotic, autotrophically grown organisms.

[Magnetic relaxation of water protons and the state of the water photodissociation system in chloroplasts]

The spin-spin relaxation time T2 of water protons is measured in chloroplast suspensions. It is shown that chloroplast lamellae efficiently increase the rate of proton magnetic relaxation, this effect being a linear function of chloroplast concentration. There is a fast exchange between the water molecules in different environments, thus the measured relaxation rate is a weight average of all water molecules. The rate of proton relaxation is decreased when membrane bound manganese is removed from chloroplasts by tris-washing procedure. The relaxation effect is slightly reduced in the presence of Photosystem II electron acceptors.

A rapid screening test for lactic aciduria

A rapid test for the determination of lactate in urine is described, which differentiates adequately between normal and elevated urine lactate levels. The method depends on the enzymatic decolourization of the blue dye dichlorophenolindophenol by lactate in the presence of the enzyme L-lactate cytochrome c oxidoreductase (EC 1.1.2.3). Interference by vitamin C is prevented by pre-treatment with charcoal. The test is simple and inexpensive, and a compact testing unit, which is stable and convenient for most laboratories, can be assembled in a glass capillary.

[Quinone-reducing activity of thrombocytes]

NAD/P/H: quinone-oxidoreductase activity was determined in human thrombocytes using spectrophotometric and polarographic methods. Detergents, vitamins K3 and K1, ADP-induced aggregation of the thrombocytes were shown to affect the thrombocytic guinone-reductase activity. Possible localization of quinone-reductase in thrombocytes and its importance for the state of thrombocytic membrane are discussed.

[Paramagnetic centers and photochemical reactions of photosystem 2 subchloroplast fragments]

ESR signals of highly purified subchloroplast fragments containing the Photosystem 2 (PS 2) were obtained. Reversibility of the ESR II signal in darkness in the presence of dichlorophenolindophenol (DCPIP) was observed. Reduction of DCPIP with chloroplast fragments in the absence of exogenous donors takes place in light without simultaneous liberation of O2. Electron transfer may be blocked by the displacement of manganese with Mg2+ and Ba2+ bivalent cations. Cd2+ cations partially suppress the electron transfer catalysed by PS 2. The inhibiting effect of Cd2+ is removed in the presence of exogenous Mn2+ or hydroxylamine.

[Relation of cyclic and noncyclic electron transport in Rhodospirillum rubrum chromatophores. I. Experimental study of the kinetic characteristics of dark reduction of P870 with different donor concentrations in the medium]

The kinetics of the dark recovery of photo-oxidized bacteriochlorophyll P870 was studied as a function of the intensity and duration of actinic light illumination at different concentrations of a donor in the medium. From the comparison of the experimental data with the results of mathematical modelling of the processes under investigation [1] it is concluded that electron transport is triggered for another pathway, whenever the concentration of the donor in the medium attains a certain critical level.