Alkaline Zone Research Articles

Removal of Dyes by Aqueous Mixed Coagulants

Alum, MgCl2, and mixtures of alum and MgCl2 have been used as coagulant to remove coloring matter in the reactive dye Levafix Brill Blue EBRA. The jar test was used to determine the effectiveness and the optimal condition of the coagulation process in terms of pH of the coagulation process, coagulant dosage, percentage color removal, and floc settling time. Coagulant dosages of 1,000-5,000 ppm were studied. The treatment of textile industry wastewater was done in the treatment plant of a printing mill. The results showed that coagulation by MgCl2 and alum occurs at the removal pH ranges of 10.5-11.0 for MgCl2 and 4.0-6.0 for alum. The mixtures of MgCl2 and alum gave two distinct effective color-removal zones at pH 4-5.5 and pH 8-9.5. The addition of alum to MgCl2 shifted the optimal pH of MgCl2 from 10.5-11. 0 to 8. 0-9.5. The alum dose of 1,000-3,000 ppm in the coagulant mixture increased by 10-25 % the color removal in the alkaline zone. Floc settling time was found to (a) increase with coagulant dose and (b) take longer in the acidic color-removal zone than in the alkaline zone. The presence of alum increased the floc settling time in the alkaline zone. The study done at the treatment plant of a printing mill showed similar results. A mixture of 60% MgClz and 40% alum at an average dosage of 2,800 ppm gave a color removal of 97% and reductions of 88% for COD and 69% for suspended solids. Keywords: Chemical coagulation, color reduction, mixed coagulants, and textile waste.

Spatial Coordination of Chloroplast and Plasma Membrane Activities in Chara Cells and Its Disruption through Inactivation of 14-3-3 Proteins

In Chara corallina cells exposed to continuous light, external pH (pH(o)) and photosystem II (PSII) photochemical yield show correlated banding patterns. Photosynthetic activity is low in cell regions producing alkaline zones and high in the acid regions. We addressed the question whether (and how) photosynthetic activity and plasma membrane (PM) H+-pumping and H+-conductance are coupled in the different bands. First, PM H+-pump activity was stimulated with fusicoccin. This resulted in a more acidic pH in the acid bands without disturbing the correlation of photosynthetic electron transport and H+ fluxes across the PM. Next, H+-pump activity was reduced through microinjection of a phosphorylated peptide matching the canonical 14-3-3 binding motif RSTpSTP in the acid cell region. Microinjection induced a rapid (~5 min) rise in pH(o) by ca. 1.0 unit near the injection site, whereas the injection of the non-phosphorylated peptide had no effect. This pH rise confirms the supposed inhibition of the H+-pump upon the detachment of 14-3-3 proteins from the H+-ATPase. However, the PSII yield in the cell regions corresponding to the new alkaline peak remained high, which violated the normal inverse relations between the pH(o) and PSII photochemical yield. We conclude that the injection of the competitive inhibitor of the H+-ATPase disrupts the balanced operation of PM H+-transport and photosynthetic electron flow and promotes electron flow through alternative pathways.

Water chemistry of mires in relation to the poor-rich vegetation gradient and contrasting geochemical zones of the north-eastern fennoscandian Shield

The relationship of the poor-rich vegetation gradient with water chemistry and geochemical bedrock zones was studied with a data set from 36 pristine mire sites in the middle boreal zone, Finland. The bipartition of bedrock zones into a granitoid zone and three other, more alkaline bedrock zones was clearly connected to the poor-rich gradient in the study area. Mires in the granitoid bedrock zone were predominantly bogs and poor fens, while most of the rich fen sites were located in other bedrock zones. In fens with strongly minerogenous hydrology, the geochemically distinct bedrock zones showed significant differences in concentrations of calcium, manganese, phosphorus, as well as in the total equivalent charge of base cations and the ratio of calcium and magnesium. In light of the indicator species baseda priori poor-rich classification anda posteriori correlations with vegetation ordinations and a poor-rich indicator cover index, pH showed the strongest relationship of the water chemical variables with the poor-rich gradient. High calcium concentrations only separated extremely rich fens from other categories. The poor-rich gradient of mires is considered as a primarily pH-related vegetation continuum. A more general use of pH-classes along with hydrological and vegetation based classification is suggested for mire classification instead of the “poor-rich” terminology.

Effect of a Single Excitation Stimulus on Photosynthetic Activity and Light-dependent pH Banding in Chara Cells

Using pH microelectrodes and a Microscopy PAM (pulse-amplitude modulated) chlorophyll fluorometer, it is shown that a propagation of an action potential in Chara corallina leads to transient suppression of spatially periodic pH profiles along the illuminated cell. The suppression was manifested as a large pH decrease in the alkaline zones and a slight pH increase in the acid zones. The propagating action potential diminished the maximum yield of chlorophyll fluorescence (F(m)') in the alkaline cell regions, as well as the quantum yield of photosystem II photochemistry, without affecting F(m)' in the acid cell regions. The results indicate an interference of membrane excitation in the mechanisms responsible for pH banding patterns in Characean algae. Apparently, the electrical excitation of the plasma membrane in the alkaline cell regions initiates a pathway that can modulate membrane events at the thylakoid membrane.

Spatio-temporal patterns of photosystem II activity and plasma-membrane proton flows in Chara corallina cells exposed to overall and local illumination.

Pulse-amplitude modulated microfluorometry and an extracellular pH microprobe were used to examine light-induced spatial heterogeneity of photosynthetic and H(+)-transporting activities in cells of Chara corallina Klein ex Willd. Subcellular domains featuring different PSII photochemical activities were found to conform to alternate alkaline and acid zones produced near the cell surface, with peaks of PSII activity correlating with the position of acid zones. Buffers eliminated pH variations near the cell surface but did not destroy the variations in PSII photochemical yield (deltaF/Fm'). When a dark-adapted cell was exposed to actinic light, the PSII effective yield decreased within 5-15 min in the alkaline regions but rose after the initial decline in the acid regions. The light-induced decrease in deltaF/Fm' in the alkaline regions occurred prior to or synchronously with the steep rise in local pH. The kinetics of deltaF/Fm', Fm', and F observed in alkaline regions under overall illumination of Chara cells were replaced by those typical of acid regions, when the illumination area size was restricted to 1.5-2 mm. The data show that photoinduced patterns in photosynthetic activity are not predetermined by the particular structural organization of alkaline and acid cell regions but are subject to dynamic changes.

Water network analysis in pulp and paper processes by pinch and linear programming techniques

Two water network optimization methods are presented. Both can be utilised to establish, without detailed design, whitewater network configurations that would minimize fresh water requirements and waste-water rejects while respecting critical contamination constraints. The essentially graphic pinch-type analysis is partially automated; it is only applicable to one contaminant system. Linear programming appears to be a more powerful tool because it can be applied simultaneously to several contaminants to be removed and fine fibers to be retained in the system while fresh water consumption is minimized. It is fully automated and particularly well adapted to large size problems. Both methods have been applied to industrial case studies with interesting results. In the case of the water network of the alkaline zone of a de-inking plant no fresh water consumption reduction was obtained, but it was shown that network rearrangement could eliminate the need for a filtration step. In the case of the complete whitewater network of an integrated newsprint mill, it was shown that it is possible to reduce the fresh water consumption by two thirds.

Distribution of Acid and Alkaline Zones on the Cell Surface of Chara corallina under Stationary and Local Illumination

A scanning microprobe technique was used to study pH distribution near the cell surface of Chara corallina Klein ex Willd. under variations of light intensity, dark–light transitions, and local illumination of various cell parts. In darkness, the H+-transporting activity of plasmalemma was distributed homogeneously over the cell surface. However, after exposing the cell to weak light (irradiance 0.2–0.5 W/m2), individual alkaline peaks with ΔpH of 1–2 units were observed in the longitudinal pH profile. The peaks in the longitudinal pH profile became more numerous with the increase in light intensity. The plot of ΔpH as a function of light intensity included a steep transition from zero to its maximum amplitude. In strong light (100 W/m2), the pH bands alternated along the cell length with a periodic length of about 7 mm. It is shown that the light-induced formation of ring-shaped bands with H+-exporting and H+ sink activities is preceded by the appearance of irregularly located spots (patches). When small cell parts were illuminated and the light spot was suddenly shifted along the cell to another position, the alkaline bands reorganized in two ways. In some cases, this treatment was followed by a gradual shift in the band position (without attenuation in the peak height) toward the illuminated area. In other cases, the initial band disappeared after such treatment, and a new alkaline band emerged in the vicinity of the illuminated area. Despite the apparent similarity of regular bands in the longitudinal pH profiles, the properties of individual bands (variable sensitivity to light intensity changes, the ability of bands to move along the cell under external treatment) differ substantially. It is supposed that the light-induced formation of the pH profile is based on primary fluctuations of photosynthetic and transport activities in the chloroplast layer and the plasmalemma, as well as on further rearrangements of membrane domains that stabilize band locations.

Comparative study on photosynthetic activity of chloroplasts in acid and alkaline zones of Chara corallina

A novel experimental approach has been applied to investigate the relationship between pH banding in Chara cells and photosynthetic activity of chloroplasts located in cell regions adjacent to acid and alkaline bands. The combination of pH microelectrode technique with pulse amplitude modulation (PAM) microfluorimetry enabled parallel measurements of longitudinal pH profiles and chlorophyll fluorescence yield in acid and alkaline zones of individual Chara cells. The scanning with a pH-microelectrode along the cell length revealed the light-dependent pH pattern, i.e., alternating acid and alkaline bands with pH differences as large as 2−3 pH units. In parallel, measurements of chlorophyll fluorescence yield under actinic light were performed using PAM microfluorometry. It was found that the effective photochemical yield of photosystem II is substantially higher in acid than in alkaline zones. The results clearly show that the banding pattern is not confined solely to the plasmalemma but is also exhibited in alternating photosynthetic performance of the underlying chloroplast layer. Apparently, the acid regions enriched with CO 2 ensure sufficient flow of this substrate to the Calvin cycle reactions, thus promoting the photosynthetic rate, whereas the alkaline zones devoid of CO 2 favor radiative losses of absorbed solar energy in chloroplasts.

Fluorescence and Photosynthetic Activity of Chloroplasts in Acid and Alkaline Zones of Chara corallina

Continuous profiles of local pH near the cell surface of Chara corallinawere recorded during uniform longitudinal movement of an internodal cell relative to a stationary pH microelectrode. Under illumination, the pH profile consisted of alternating acid and alkaline bands with a pH difference of up to 3 pH units. After darkening, the bands disappeared and pH became uniformly distributed along the cell length. Chlorophyll fluorescence of chloroplasts was measured by microfluorometry at different locations within one cell, and significant differences were observed in close relation to light-dependent pH banding. The chlorophyll fluorescence yield was lower in zones of low external pH than in alkaline zones both under actinic and saturating light. The fluorescence parameters Fand F" m and the quantum yield of photosystem II (PSII) displayed variations along the cell length in accordance with pH changes in unstirred layers of the medium. The results show that PSII photochemical efficiency and the rate of noncyclic electron transport are higher in the chloroplasts of acid zones (zones of H+extrusion from the cell) than in alkaline zones. The dependence of photosynthetic electron transport on local pH near the cell surface may result from different contents of CO2in acid and alkaline regions. The acid zones are enriched with CO2that readily permeates through the membrane providing the substrate for the Calvin cycle. Conversely, a poorly permeating form, HCO–3is predominant in alkaline zones, which may restrict the dark reactions and photosynthetic electron flow.

Comparison of ZnO and ZnSO4 for Correcting Severe Foliar Zinc Deficiency in Pecan

Ground applications of ZnO to large mature pecan [Carya illinoinensis (Wangenh.) K. Koch] trees in orchards possessing an acidic soil, but with a culturally induced slightly alkaline soil surface zone, were at least as effective as was ZnSO4 for rapidly correcting severe foliar Zn deficiency, improving in-shell nut production, and maintaining kernel quality. Under such soil conditions, light disking of Zn applied at 160 kg·ha-1 from ZnO elevated foliar Zn above the sufficiency level by the second growing season after application; whereas an absence of disking delayed substantial uptake from ZnO until the fourth growing season. ZnO, usually a lower priced Zn source, was as effective as was ZnSO4 for correcting Zn deficiencies via broadcast ground application; however, same season correction of Zn deficiency was best accomplished by the standard practice of using foliar sprays of ZnSO4 rather than by heavy soil applications of either Zn source.

Relationship between banding and photosynthetic activity in Chara corallina as studied by the spatially different induction curves of chlorophyll fluorescence observed by an image analysis system

Image analysis was applied for studying the kinetics of chlorophyll fluorescence in the alkaline and acid zones of internodal cells of Chara corallina Klein ex Willd., in order to test the hypothesis that in the acid bands an outward proton current yields a conversion of HCO3− ions to CO2, thus facilitating inward diffusion of CO2.The analysis of the responses of chlorophyll fluorescence induced by changes in light intensity from 0.15 W m−2 to 2.0 W m−2 (λ <580 nm) revealed different kinetic behaviour. In the alkaline zones, the amplitude of the variable components of fluorescence was smaller than in the acid zones. Curve fitting by a sum of exponentials showed that the 4 time constants of about 2, 22, 48 and 140 s were not significantly different between the alkaline and acid zones. In contrast the related amplitude factors were smaller in the alkaline zones. by a factor of about 1.6 to 2.0 in old calcified cells and by a factor of about 1.2 in young cells without acrustations.The interpretation of these results in terms of a better supply of carbon dioxide in the acid zones was supported by investigations on leaves of tobacco. Lowering the CO2 concentration of an artificial atmosphere below 20 ppm resulted in a similar reduction of the variable component of chlorophyll fluorescence as found in the alkaline zones of Chara.

Diffusion nuclear magnetic resonance imaging in experimental stroke. Correlation with cerebral metabolites.

Diffusion-weighted nuclear magnetic resonance imaging has been shown to detect early ischemia-related alterations in experimental stroke. This raises the question of whether the observed increase in signal intensity is correlated with changes in cerebral metabolism. After middle cerebral artery occlusion, nuclear magnetic resonance diffusion images were recorded and compared with the regional concentration of cerebral metabolites and with histology of identical planes. Seven anesthetized Fischer rats were subjected to permanent occlusion of the middle cerebral artery. T1, T2, and diffusion images (b factors ranging from 0 to 1500 s/mm2) were measured in three to five planes after 7 hours. Thereafter, brains were frozen in situ for histology and quantitative bioluminescence imaging of ATP, glucose, lactate, and for fluorescence imaging of tissue pH. Seven hours after middle cerebral artery occlusion, the apparent diffusion coefficient was reduced from 615 +/- 97 x 10(-6).mm2.s-1 (contralateral brain) to 359 +/- 42 x 10(-6).mm2.s-1 (ischemic brain; mean +/- SD, P < .01). A precise topical coincidence was demonstrated between changes in nuclear magnetic resonance diffusion images, pattern of histological damage, ATP-depleted areas, and local tissue acidosis, the lesion area amounting to between 24.1% and 27.6% of the hemisphere at the level of the caudate-putamen. The area of elevated brain lactate clearly exceeded the acidic core of the infarct and included the slightly alkaline border zone. The data demonstrate that after 7-hour middle cerebral artery occlusion, the reduction of the apparent diffusion coefficient in nuclear magnetic resonance diffusion images reflects precisely the region of histological injury, breakdown of energy metabolism, and tissue acidosis.

Formation of band-type electric patterns in Characean cells

It is observed by experiments that band patterns of alternating acid and alkaline zones are formed on the surface of Characean cells under illumination. In order to understand theoretically such pattern formation, we employ a reaction-diffusion equation model with activator-inhibitor interaction. We study the existence problem of band patterns and hysteresis phenomena such as patterns appearing and disappearing with changing light intensity by using singular perturbation methods.

Calcification in Chara corallina: CO2 hydroxylation generates protons for bicarbonate assimilation

The alga Chara corallina (Charophyta, Charophyceae) apparently generates protons through the hydroxylation and precipitation of CO2, which leaks from the cell into highly alkaline pericellular regions. Under mildly alkaline conditions, the loss of CO2 to calcification is compensated by the production of twice as much CO2 from HCO3−, using the protons generated during calcification.Experiments capitalize on Chara’s large cells with their alternating alkaline (calcareous) and acidic (noncalcareous) pericellular zones. 14C uptake into carbonate and organic phases is fastest when the isotope is applied to the acidic zones. The ratio of calcification to photosynthesis is ∼ 1 at pH 8 and increases with pH approximately as simulated by a model in which both calcification and photosynthesis use carbon assimilated in the acidic zones. PIPES buffer (pKa = 6.8) inhibits calcification and photosynthesis equally, suggesting competition with bicarbonate as a proton acceptor in the acidic zones. CAPS buffer (pKa = 10.4) has little effect, suggesting that exogenous bicarbonate is not very important for calcification. Divalent Sr and Mn added to the medium precipitate primarily between the cell and calcareous encrustations, but phosphate does not. This result is consistent with the use of cellular Ca and CO2 in extracellular calcification.

アガロース等電点電気泳動による神経変性疾患の髄液蛋白分画

The cerebrospinal fluid protein fractions were investigated by the agarose isoelectric focusing (agarose IEF) and the silver staining, for the purpose of elucidating protein abnormalities in the neural tissues in the degenerative neurological diseases, especially in motor neuron disease (MND), spinocerebellar degeneration (SCD) and Parkinson disease (PD).In this study, we focused six bands, mainly composed of transferrin, separated by agarose IEF and the silver staining. Some of these bands showed double fractions, even in the cases of the control group consisted of the patients without organic disease. In MND, all patients had double fractions of one or more of these bands, and it was interesting that in some of them double fractions were seen on the band with the isoelectric point of 5.6. Double fractions were also seen in many of SCD (69%) and PD (91%). Cases in that there was positive in more alkaline zone than transferrin in this method, were more in disease groups (especially in MND and SCD) than in the control group.This method combined agarose IEF with the silver staining seemed to be the excellent one as the investigating procedure for cerebrospinal fluid proteins.

Gastric mucosal defence mechanisms.

Gastric mucosa has a particular ability to resist acid/peptic digestion. The nature of the presumed barrier to acid and pepsin has been elusive but recent work suggests that a combination of mechanisms is likely to be involved. Amongst these the mucus gel layer combined with secretion of alkali by the surface epithelium is likely to form a first line defence. The demonstration of a pH gradient within the mucus gel layer supports such a hypothesis. Agents which damage the mucosa such as aspirin and bile salts inhibit the maintenance of the pH gradient allowing the luminal surface of the epithelium to become more acid. Prostaglandins enhance this pH gradient, an observation which may be relevant to the protective properties of prostaglandins. This alkaline zone can be compromised by high levels of luminal acidity and it thus has a limited capacity to prevent acid reaching the mucosa. The local microcirculation is of importance in maintaining surface epithelial metabolic integrity and interstitial fluid bicarbonate may be important in neutralising any acid which may reach the subepithelial layers. This may in part explain the ability of an actively secreting gastric epithelium to resist damage to a greater extent than a resting mucosa. Recent exciting work has focussed on the ability of gastric epithelium to reform by a process which has been termed restitution, after acute mucosal damage. This process appears to be rapid and occurs within an hour or so. Repeated rapid repair may be a common occurrence in the maintenance of mucosal integrity. Finally, it has been proposed that a hydrophobic property of surface epithelium in the stomach may be relevant to mucosal protection.

Growing hyphae of Achlya bisexualis generate a longitudinal pH gradient in the surrounding medium.

Growing hyphae of Achlya bisexualis were found to generate a longitudinal pH gradient in the surrounding medium; the medium adjacent to the tip was slightly more alkaline than the bulk phase, while that near distal parts was acidic. The profile of external pH paralleled that of electric current, as measured with a vibrating probe; the apical alkaline zone corresponded to the region of current inflow. In organisms grown in complete medium, both current flow and apical alkalinization were inhibited when amino acid uptake was blocked, either by removing amino acids from the medium or by raising the external pH to 8.5. Achlya could, however, adapt to a medium deficient in organic nutrients; elongating hyphae again generated both the pH profile and the transcellular electric current. It is proposed that both the pH profile and the electric current are manifestations of a transcellular proton current, which arises from the segregation of proton pumps from proton leaks. Symport of protons with amino acids may be one mechanism by which protons enter the hyphal apex.

Transcellular ion currents in the water mold Achlya. Amino acid proton symport as a mechanism of current entry.

Achlya, like other tip-growing organisms, generates an endogenous electrical current such that positive charge flows into the hyphal apex and exits from the trunk. The present study is concerned with the mechanism of current generation by hyphae growing in a defined, complete medium. The intensity of the current, measured in the extracellular medium with a vibrating probe, was unaffected by the removal of all the inorganic constituents of the growth medium. However, an increase in the external pH or the deletion of amino acids abolished the current. Removal of methionine alone diminished the current by two thirds. Hyphae also generated a longitudinal pH gradient in the extracellular medium; the region surrounding the tip was more alkaline than the bulk medium, whereas the region around the trunk was relatively acidic. These findings suggest that a flux of protons, dependent upon amino acids in the medium, carries current into the tip and creates the surrounding alkaline zone. The proton current appears to result from the transport of amino acids rather than their metabolism. Conditions that abolished the current also inhibited methionine uptake but had little effect on the respiratory rate. The findings imply a connection between the proton current and chemiosmotic energy transduction. We propose that protons flow into the hyphal tip through amino acid/proton symporters that are preferentially localized there. The proton flux energizes the uptake of amino acids into the growing zone and may also contribute to the polarization of hyphal growth.

Spatial Variation of the Electrical Properties of Chara australis. I Electrical Potentials and Membrane Conductance

Experiments are described with cells of Chara, using a water-film technique, to determine the dependence on position along the cells of the membrane conductance, electromotive force (e.m.f.) and noise spectrum. It was found that both the e.m.f. and the conductance were far from uniform along the cells. The e.m.f. showed distinct zoning patterns, regions of greater e.m.f. (acid zones) having potentials of up to 70 mV greater than the zones of minimum e.m.f. (alkaline zones). In the alkaline zones the conductance was ≈ 3.5 times larger than in the acid zones. The noise spectra of the membrane potential in both the acid and alkaline zones were similar, despite the differences in membrane conductance. The details of the results presented are consistent with the motion that in the acid zones the potential is hyperpolarized by the operation of an active H+ transport system, whilst in the alkaline zones the membrane is in a proton-permeable state (in which the conduction mechanism itself may be fluctuating).

Spatial Variation of the Electrical Properties of Chara australis. II. Membrane Capacitance and Conductance as a Function of Frequency

The water-film technique has been used to measure the frequency dependence of the membrane capacitance and conductance as a function of position along illuminated cells of C. australis. At low frequencies (&lt; 1 Hz) the behaviour of the membrane capacitance was found to be strongly dependent upon both frequency and position. A complicated oscillatory pattern was observed which is possibly linked to interference effects between the impressed alternating current and the current normally circulating between alternate acid and alkaline zones. The area-specific membrane conductance was always higher in the alkaline zones than in the acid zones and at low frequencies was 0.45 - 1.3 S m-2 and 2.9 - 3.6 S m-2 respectively. The temperature dependence of the variation of the capacitance and conductance with frequency was also different in the acid and alkaline zones. The observed spatial and frequency dependence of the membrane electrical parameters is clearly associated with the dynamic homeostatis of the cell, and has consequences for the construction of realistic electrical models for the membrane of C. australis.