Acidic Pool Research Articles

Rediscovery of Tetraëdriella subglobosa Pascher, a member of the Eustigmatophyceae

An algal strain from an acidic pool near the shore of Lake Macha, Czech Republic, was identified as Tetraedriella subglobosa Pascher by light microscopy. Phylogenetic analysis of nuclear 18S rDNA and plastid rbcL sequence data indicated that this alga is a member of the Eustigmatophyceae, rather than the Xanthophyceae as presently classified. This is the first report of T. subglobosa since Pascher's description of the species in 1930.

Phosphorus Fractionations in Ganges Tidal Floodplain Soil of Bangladesh

CORRECTION: Due to a number of formatting and layout issues, the PDF of this paper was replaced on 10th October 2016. The page numbers of this article have changed from 55-61 to 57-63.The present investigation aimed to evaluate different fractions of P of Ganges tidal floodplain soils of Bangladesh in terms of plant availability in the selected soil. The samples were analyzed for solution P, labile pool, alkali-extracted inorganic pool, organic pool, acidic pool and residual P.The soil solution P in the tested soils ranged from 0.03 to 0.11 mg L–1. The concentration of 0.5M NaHCO3 extracted P had a range of 8-34 mg kg–1. Dilute NaOH extracted inorganic P had a range of 25-59 mg kg–1. NaOH extracted organic P ranged from 334 to 542 mg kg–1 and acid extracted P represented from 140 to 443 mg kg–1, respectively. Residual P of the tested soils showed a concentration of 104-262 mg kg–1. On average of the 12 soils, the relative concentration of solution P was 0.01%, NaHCO3 P was 3.2%, NaOH-Pi was 6.8%, NaOH-Po was 44.6%, acid pool was 27.3% and residual fraction was 18.1%. Different P pools showed strong correlation either with sand, silt, clay, electrical conductivity, pH(H2O), pH (KCl), organic carbon or extractable Fe content. The tested Ganges tidal floodplain soils demonstrated wide variation in the relative proportion of different P pools.Bangladesh Rice j. 2015, 19(2): 57-63

Phosphorus Fractionations in Acidic Piedmont Rice Soils

Piedmont lands in Bangladesh, India, Nepal, and many other Asian countries are important rice-growing soils, but most of the soils are potentially phosphorus (P) deficient because of low pH. Phosphorus fractions of rice-growing acidic piedmont soils were determined. Soil samples were amended with 100 and 200 mg P kg−1 soil, and a control soil without P amendment was maintained. The samples were analyzed for the following fractions: solution P, labile pool [sodium bicarbonate (NaHCO3) P], alkali-extracted inorganic pool [sodium hydroxide (NaOH) Pi], organic pool (NaOH Po), acidic pool [sulfuric acid (H2SO4)−hydrochloric acid (HCl) P], and residual P. About 98% of the applied P in soils was extracted by the sequential extraction employed in the present experiment. The mean total P concentration in 10 acidic Piedmont soils was 247 ppm, of which only 0.12% was in solution, 8% labile (NaHCO3), 16% NaOH-extracted inorganic, 32% resistant organic, 18% relatively recalcitrant acidic, and 25% residual. Application of P fertilizer increased mainly the labile P fraction, which would be easily available to wetland rice. Solution P was positively and significantly correlated with pHKCl (r = 0.64, P < 0.05) and negatively correlated with clay (r = −0.77, P < 0.01). A negative and significant correlation of NaHCO3-P was observed with pHH2O (r = −0.62, P < 0.05). Solution P showed a negative and significant relationship with NaOH-Pi (r = −0.63, P < 0.05). A significant and negative relationship of solution P was also observed with acid P (r = −0.78, P < 0.01) and residual P (r = −0.82, P < 0.01). The relationship of NaHCO3-P with NaOH-Pi was positive (r = 0.70, P < 0.05) and significant. Similarly, a positive and significant relationship (r = 0.89, P < 0.01) between NaOH-Pi and acid P was observed, and acid P was positively and significantly correlated with residual P (r = 0.84, P < 0.01).

Calcium signalling and pancreatic cell death: apoptosis or necrosis?

Secretagogues, such as cholecystokinin and acetylcholine, utilise a variety of second messengers (inositol trisphosphate, cADPR and nicotinic acid adenine dinucleotide phosphate) to induce specific oscillatory patterns of calcium (Ca(2+)) signals in pancreatic acinar cells. These are tightly controlled in a spatiotemporal manner, and are coupled to mitochondrial metabolism necessary to fuel secretion. When Ca(2+) homeostasis is disrupted by known precipitants of acute pancreatitis, for example, hyperstimulation or non-oxidative ethanol metabolites, Ca(2+) stores (endoplasmic reticulum and acidic pool) become depleted and sustained cytosolic [Ca(2+)] elevations replace transient signals, leading to severe consequences. Sustained mitochondrial depolarisation, possibly via opening of the mitochondrial permeability transition pore (MPTP), elicits cellular ATP depletion that paralyses energy-dependent Ca(2+) pumps causing cytosolic Ca(2+) overload, while digestive enzymes are activated prematurely within the cell; Ca(2+)-dependent cellular necrosis ensues. However, when stress to the acinar cell is milder, for example, by application of the oxidant menadione, release of Ca(2+) from stores leads to oscillatory global waves, associated with partial mitochondrial depolarisation and transient MPTP opening; apoptotic cell death is promoted via the intrinsic pathway, when associated with generation of reactive oxygen species. Apoptosis, induced by menadione or bile acids, is potentiated by inhibition of an endogenous detoxifying enzyme NAD(P)H:quinone oxidoreductase 1 (NQO1), suggesting its importance as a defence mechanism that may influence cell fate.

Bile Acids Induce Ca2+ Release from Both the Endoplasmic Reticulum and Acidic Intracellular Calcium Stores through Activation of Inositol Trisphosphate Receptors and Ryanodine Receptors

Gallstones can cause acute pancreatitis, an often fatal disease in which the pancreas digests itself. This is probably because of biliary reflux into the pancreatic duct and subsequent bile acid action on the acinar cells. Because Ca(2+) toxicity is important for the cellular damage in pancreatitis, we have studied the mechanisms by which the bile acid taurolithocholic acid 3-sulfate (TLC-S) liberates Ca(2+). Using two-photon plasma membrane permeabilization and measurement of [Ca(2+)] inside intracellular stores at the cell base (dominated by ER) and near the apex (dominated by secretory granules), we have characterized the Ca(2+) release pathways. Inhibition of inositol trisphosphate receptors (IP(3)Rs), by caffeine and 2-APB, reduced Ca(2+) release from both the ER and an acidic pool in the granular area. Inhibition of ryanodine receptors (RyRs) by ruthenium red (RR) also reduced TLC-S induced liberation from both stores. Combined inhibition of IP(3)Rs and RyRs abolished Ca(2+) release. RyR activation depends on receptors for nicotinic acid adenine dinucleotide phosphate (NAADP), because inactivation by a high NAADP concentration inhibited release from both stores, whereas a cyclic ADPR-ribose antagonist had no effect. Bile acid-elicited intracellular Ca(2+) liberation from both the ER and the apical acidic stores depends on both RyRs and IP(3)Rs.

Characterization of a photosynthetic Euglena strain isolated from an acidic hot mud pool of a volcanic area of Costa Rica1

Abstract Conspicuous green patches on the surface of an acidic hot mud pool located near the Rincón de la Vieja volcano (northwestern Costa Rica) consisted of apparently unialgal populations of a chloroplast-bearing euglenoid. Morphological and physiological studies showed that it is a non-flagellated photosynthetic Euglena strain able to grow in defined mineral media at temperatures up to 40 degrees C and exhibiting higher thermotolerance than Euglena gracilis SAG 5/15 in photosynthetic activity analyses. Molecular phylogeny studies using 18S rDNA and GapC genes indicated that this strain is closely related to Euglena mutabilis, another acid-tolerant photosynthetic euglenoid, forming a clade deeply rooted in the Euglenales lineage. To our knowledge this is the most thermotolerant euglenoid described so far and the first Euglenozoan strain reported to inhabit acidic hot aquatic habitats.

Complex xylo-oligosaccharides identified from hydrothermally treated Eucalyptus wood and brewery's spent grain

Hydrolysates from two hydrothermally treated xylan-rich agrobased materials, Eucalyptus wood and brewery's spent grain were fractionated by anion-exchange chromatography and size-exclusion chromatography. Hereby, several pools were obtained and they were characterised by their sugar composition. Additionally, the oligosaccharides in the pools described were further identified by high-performance anion-exchange chromatography and mass spectrometry. The hydrothermally treated brewery's spent grain resulted in three pools of which two contained relatively high molecular weight xylan, singly and doubly branched with arabinose [X n A m ], separated from a pool of xylo-oligosaccharides less branched with arabinose. The fractionation of the hydrothermally treated Eucalyptus wood resulted in a neutral pool, mainly consisting of a series of (acetylated) xylo-oligosaccharides [X n Ac m ], and three acidic pools. Two of these acidic pools contained a series of (acetylated) xylo-oligosaccharides including one 4- O-methylglucuronic acid [X n (GlcA me) 1Ac m ], while the third acidic pool contained (acetylated) xylo-oligosaccharides substituted with two 4- O-methylglucuronic acids [X n (GlcA me) 2Ac m ]. Additionally, a series of xylo-oligosaccharides containing both 4- O-methylglucuronic acid and a hexose, most likely galactose, was detected in the acidic Eucalyptus pools [X n (GlcA me) 1 or 2 Ac m H]. Information was obtained about the number of acetyl-groups linked to the (4- O-methylglucurono-) xylo-oligosaccharides. Finally, it is demonstrated with an example that the different substituents to the xylo-oligosaccharides present are of relevance for the fermentability of the xylo-oligosaccharides by human faecal samples.

Red blood cells of the lizards Ameiva ameiva (Squamata, Teiidae) display multiple mechanisms to control cytosolic calcium

We have previously reported that lizard red blood cells control their cytosolic calcium concentration by sequestering calcium ions in pools, which could be discharged by thapsigargin, by the Na+/H+ ionophore, monensin, by the K+/H+ ionophore, nigericin and by the proton pump inhibitor, bafilomycin A1 [1]. We have now demonstrated, with the aid of confocal microscopy, the presence in these cells of organelles, which accumulate the dye acridine orange and are thus by inference the sites of proton pools. We have found, moreover, that monensin, nigericin and bafilomycin all act to discharge these pools. We further show that calcium release ensues when the calcium ionophore, ionomycin, is added after thapsigargin and monensin; this implies the existence of a third pool, besides the acidic pool and the Endoplasmic Reticulum (ER), which participates in calcium homeostasis. The ER calcium pool can de discharged by the addition of the second messenger, IP3, and we present evidence, based on confocal microscopy, that the IP3 receptors are located in or close to the nucleus.

Use of reversed-phase and ion-exchange batch extraction in the purification of bovine pituitary peptides

Bovine posterior pituitaries were extracted with an acidic medium designed to maximize solubilization of peptides while precipitating high-molecular-weight protein. The supernatant was then extracted with C 18 reversed-phase cartridges to generate a peptide-enriched fraction. Cartridge eluates were subjected to ion-exchange extraction, using a batch procedure which fractionated the peptides into basic, acidic, and neutral pools. Amino-terminal fragments of bovine pro-opiomelanocortin were found to be resolved into separate pools by this method. The 1 to 49 fragment was eluted in the acidic pool while the 1 to 77 fragment was eluted in the basic pool. The 1 to 77 fragment was purified by reversed-phase high-performance liquid chromatography. Amino acid analysis of the fragments, generated from trypsin and V 8 protease digestion of the 1 to 77 fragment, permitted assignment of cystine bridges between residues 2 and 24 and between residues 8 and 20. Results from amino sugar analysis were consistent with the presence of an O-linked oligosaccharide at threonine 45 and an N-linked oligosaccharide at asparagine 65.

PERIODICITY OF EPIPELIC UNICELLULAR VOLVOCALES (CHLOROPHYCEAE) IN A SHALLOW ACID POOL1

ABSTRACTThe occurrence, periodicity and growth of twenty species of unicellular Volvocales on sediments in an acidic pool are described. Minimum populations were recorded in winter, but during the rest of the year standing crops fluctuated rapidly. The greatest species diversity and primary productivity occurred in late spring‐early summer and in autumn, when maximum numbers of Chlamydomonas spp. and Chloromonas spp. increased exponentially on the sediments. The chlamydomonads were more numerous in the epipelon than other major algal components such as diatoms, euglenoids, bluegreen algae and desmids. Growth of the chlamydomonad population occurred after the period of maximum diatom standing crop. Evidence shows that rates of primary production were greater in late spring and late summer when species diversity and standing crop or apparent growth rates of unicellular Volvocales were high. Thus these algae which are normally neglected may be more important in primary productivity than previously believed since they grow during periods when larger algae are scarce. Analysis of the data using the multivariate technique of Reciprocal Averaging confirmed seasonal periodicity in this community of epipelic flagellates. It also identified species with distinctive ecological requirements. A relationship between the bicarbonate‐alkalinity of the overlying water and the chlamydomonad population was demonstrated by ordination analysis.