scholarly journals Calcium fluxes in Hoplosternum littorale (tamoatá) exposed to different types of Amazonian waters

2009 ◽  
Vol 7 (3) ◽  
pp. 465-470 ◽  
Author(s):  
Bernardo Baldisserotto ◽  
Carlos Eduardo Copatti ◽  
Levy Carvalho Gomes ◽  
Edsandra Campos Chagas ◽  
Richard Philip Brinn ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Water Transfer ◽  
Well Water ◽  
Acidic Ph ◽  
Clear Water ◽  
Black Water ◽  
Neutral Ph ◽  
Different Types ◽  
White Water ◽  
Hoplosternum Littorale

Fishes that live in the Amazonian environment may be exposed to several kinds of waters: "black waters", containing high dissolved organic carbon and acidic pH, "white waters", with ten fold higher Ca2+ concentrations than black waters and neutral pH, and "clear waters", with two fold higher Ca2+ concentrations than black waters and also neutral pH. Therefore, the aim of the present study was to analyze Ca2+ fluxes in the facultative air-breather Hoplosternum littorale (tamoatá) exposed to different Amazonian waters. Fishes were acclimated in well water (similar to clear water) and later placed in individual chambers for Ca2+ fluxes measurements. After 4 h, water from the chambers was replaced by a different type of water. Transfer of tamoatás to ion-poor black or acidic black water resulted in net Ca2+ loss only in the first 2 h of experiment. However, transfer from black or acidic black water to white water led to only net Ca2+ influxes. The results obtained allowed us to conclude that transfer of tamoatás to ion-poor waters (black and acidic black water) led to transient net Ca2+ loss, while the amount of Ca2+ in the ion-rich white water seems adequate to prevent Ca2+ loss after transfer. Therefore, transfer of tamoatás between these Amazonian waters does not seem to result in serious Ca2+ disturbance.

scholarly journals Origin and nature of humic substances in the waters of the Amazon River Basin

1980 ◽  
Vol 10 (3) ◽  
pp. 513-526 ◽  
Author(s):  
Jerry A. Leenheer
Keyword(s):  
United States ◽  
Organic Carbon ◽  
Humic Substances ◽  
River Basin ◽  
Surface Waters ◽  
Southeastern United States ◽  
Organic Solutes ◽  
Clear Water ◽  
Black Water ◽  
Organic Solute

Abstract Humic substances dissolved in "black water, white water, and clear water" rivers of the Amazon River basin were compared were humic substances found in podzolic (spodic) and latosolic (oxic) soils of the Amaon region. Humic-type organic solutes in black water originated from organic matter decomposition and ground water drainage from podzolic soils; clear water drains from latosols because colored humic solutes are adsorbed on clay minerals contained in latosols. Comparisons of organic solute distributions in tropical surface waters versus temperate surface waters by dissolved organic carbon fractionation analysis chow that the only significant difference was a lower hydrophilic neutral content of tropical surface waters. This finding is indicative of more rapid decay processes In tropical waters. Black-water rivers of the Amazon contained cndy one-third to one-half the organic solute content contained in black-water rivers of the southeastern United States. About 50 percent of the organic carbon In black waters of the Amazon consisted of colorless non-humic organic solutes. Humic solutes contained in Amazon black water differed from humic solutes found In the Suwannee River in the southeastern United States by having a higher E4/E6 ratio in the visible absorbance spectrum which resulted in water of a more reddish coloration. Both the high E4/E6 ratio and low-angle x-ray scattering data suggest relatively small molecular dimensions for humic solutes in Amazon black water. Organic elemental analyses and infrared analysis of humic substances in Amazon waters and soils were typical for humic substances except for the low content of nitrogen for humic solutes in black water.

scholarly journals The Listeria monocytogenes hemolysin has an acidic pH optimum to compartmentalize activity and prevent damage to infected host cells

2002 ◽  
Vol 156 (6) ◽  
pp. 1029-1038 ◽  
Author(s):  
Ian J. Glomski ◽  
Margaret M. Gedde ◽  
Albert W. Tsang ◽  
Joel A. Swanson ◽  
Daniel A. Portnoy
Keyword(s):  
Listeria Monocytogenes ◽  
Bacterial Pathogen ◽  
Cytolytic Activity ◽  
Host Cells ◽  
Adaptive Mutation ◽  
Acidic Ph ◽  
Listeriolysin O ◽  
Lysosomal Hydrolases ◽  
Ph Optimum ◽  
Neutral Ph

Listeria monocytogenes is a facultative intracellular bacterial pathogen that escapes from a phagosome and grows in the host cell cytosol. The pore-forming cholesterol-dependent cytolysin, listeriolysin O (LLO), mediates bacterial escape from vesicles and is ∼10-fold more active at an acidic than neutral pH. By swapping dissimilar residues from a pH-insensitive orthologue, perfringolysin O (PFO), we identified leucine 461 as unique to pathogenic Listeria and responsible for the acidic pH optimum of LLO. Conversion of leucine 461 to the threonine present in PFO increased the hemolytic activity of LLO almost 10-fold at a neutral pH. L. monocytogenes synthesizing LLO L461T, expressed from its endogenous site on the bacterial chromosome, resulted in a 100-fold virulence defect in the mouse listeriosis model. These bacteria escaped from acidic phagosomes and initially grew normally in cells and spread cell to cell, but prematurely permeabilized the host membrane and killed the cell. These data show that the acidic pH optimum of LLO results from an adaptive mutation that acts to limit cytolytic activity to acidic vesicles and prevent damage in the host cytosol, a strategy also used by host cells to compartmentalize lysosomal hydrolases.

scholarly journals Influence of trees and associated variables on soil organic carbon: a review

2021 ◽  
Vol 45 (1) ◽  
Author(s):  
Angom Sarjubala Devi
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Significant Negative Correlation ◽  
Mean Annual Temperature ◽  
Forest Stands ◽  
Mixed Stands ◽  
Silt Fraction ◽  
Different Types ◽  
Soil Climate ◽  
Associated Variables

AbstractThe level of soil organic carbon (SOC) fluctuates in different types of forest stands: this variation can be attributed to differences in tree species, and the variables associated with soil, climate, and topographical features. The present review evaluates the level of SOC in different types of forest stands to determine the factors responsible for the observed variation. Mixed stands have the highest amount of SOC, while coniferous (both deciduous-coniferous and evergreen-coniferous) stands have greater SOC concentrations than deciduous (broadleaved) and evergreen (broadleaved) tree stands. There was a significant negative correlation between SOC and mean annual temperature (MAT) and sand composition, in all types of forest stands. In contrast, the silt fraction has a positive correlation with SOC, in all types of tree stands. Variation in SOC under different types of forest stands in different landscapes can be due to differences in MAT, and the sand and silt fraction of soil apart from the type of forests.

NMR studies of exocyclic 1,N2-propanodeoxyguanosine adducts (X) opposite purines in DNA duplexes: protonated X(syn).cntdot.A(anti) pairing (acidic pH) and X(syn).cntdot.G(anti) pairing (neutral pH) at the lesion site

Biochemistry ◽  
1989 ◽  
Vol 28 (13) ◽  
pp. 5647-5657 ◽  
Author(s):  
Michael Kouchakdjian ◽  
Edmund Marinelli ◽  
Xiaolian Gao ◽  
Francis Johnson ◽  
Arthur Grollman ◽  
...  
Keyword(s):  
Acidic Ph ◽  
Dna Duplexes ◽  
Lesion Site ◽  
Nmr Studies ◽  
Neutral Ph

scholarly journals Visible-Light-Driven Water Oxidation on Self-Assembled Metal-Free Organic@Carbon Junctions at Neutral pH

JACS Au ◽  
2021 ◽  
Author(s):  
Astrid J. Olaya ◽  
Julieta S. Riva ◽  
Dominika Baster ◽  
Wanderson O. Silva ◽  
François Pichard ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Visible Light ◽  
Water Oxidation ◽  
Metal Free ◽  
Neutral Ph ◽  
Visible Light Driven ◽  
Self Assembled

scholarly journals Benthic organic carbon release stimulates bacterioplankton production in a clear-water subarctic lake

2013 ◽  
Vol 32 (1) ◽  
pp. 176-182 ◽  
Author(s):  
Patricia Rodríguez ◽  
Jenny Ask ◽  
Catherine L Hein ◽  
Mats Jansson ◽  
Jan Karlsson
Keyword(s):  
Organic Carbon ◽  
Clear Water ◽  
Bacterioplankton Production ◽  
Carbon Release ◽  
Subarctic Lake

scholarly journals Inactivation of tyrosine aminotransferase in neutral homogenates and rat liver slices

1972 ◽  
Vol 129 (5) ◽  
pp. 1131-1138 ◽  
Author(s):  
F. Auricchio ◽  
L. Mollica ◽  
A. Liguori
Keyword(s):  
Amino Acid ◽  
Rat Liver ◽  
Acid Concentration ◽  
Tyrosine Aminotransferase ◽  
Amino Acid Concentration ◽  
Acidic Ph ◽  
Ph Values ◽  
Neutral Ph ◽  
Liver Slices

Inactivation of tyrosine aminotransferase induced in vivo by triamcinolone was studied in a homogenate incubated at neutral pH values. The integrity and the presence of subcellular particles together with a compartment of acidic pH are necessary for inactivation of tyrosine aminotransferase. It is suggested that tyrosine aminotransferase is inactivated inside lysosomes. The system responsible for inactivation of tyrosine aminotransferase was partially purified and identified with lysosomal cathepsins B and B1. Inactivation of tyrosine aminotransferase in liver slices is controlled by the amino acid concentration and strongly stimulated by cysteine. 3,3′,5-Tri-iodo-l-thyronine reversibly and strongly decreases the rate of inactivation of tyrosine aminotransferase. The effect is not due to an increased rate of tyrosine aminotransferase synthesis.

Composition and community structure of mangroves distributed on the east coast of Marajó Island, Brazil

2022 ◽  
Author(s):  
Barbara Luzia Santos de Oliveira Faro ◽  
Priscila Sanjuan de Medeiros-Sarmento ◽  
Norma Ely Santos Beltrão ◽  
Paulo Weslem Portal Gomes ◽  
Ana Cláudia Caldeira Tavares-Martins
Keyword(s):  
Floristic Composition ◽  
Distribution Patterns ◽  
Major Influence ◽  
Structural Development ◽  
Black Water ◽  
Composition And Structure ◽  
Marine System ◽  
Marajó Island ◽  
White Water ◽  
Degree Of Similarity

Abstract Mangroves in the Amazon are influenced by several environmental conditions that determine the composition and structural development of the arboreal flora, which results in different distribution patterns. In this study, we sought to answer two questions: (1) what is the composition and structure of the mangroves near the mouth of the Amazon River in Marajó Island? (2) Are the fringe and inland mangroves more similar or dissimilar in terms of floristic composition? For this, we delimited a fringe zone and an inland zone about 1 km apart from each other. In each zone, we distributed five 400-m2 plots. The individuals were grouped into diameter and height classes and structural and phytosociological parameters were calculated. Ten species were recorded in the mangroves, of which seven are typical of white-water (várzea) and black-water (igapó) flooded forest ecosystems. We believed the adjacent ecosystems and the hydrological network are inducing the establishment of such species. The composition and structure of mangroves did not differ statistically between zones, and the degree of similarity may be a result of similar environmental factors in these zones such as low relief and high frequency of macrotides. We conclude that the vegetation of the studied mangroves has a major influence of the fluvial-marine system of the great rivers of the Amazon associated with a diversity of ecosystems that, together, generate greater floristic richness when compared to mangroves in other regions.

scholarly journals Distribution Characteristic of Soil Organic Carbon Fraction in Different Types of Wetland in Hongze Lake of China

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Yan Lu ◽  
Hongwen Xu
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Microbial Biomass Carbon ◽  
Carbon Sink ◽  
Flood Plain ◽  
Estuarine Wetland ◽  
Correlative Analysis ◽  
Hongze Lake ◽  
Different Types ◽  
Organic Carbon Fractions

Soil organic carbon fractions included microbial biomass carbon (MBC), dissolved organic carbon (DOC), and labile organic carbon (LOC), which was investigated over a 0–20 cm depth profile in three types of wetland in Hongze Lake of China. Their ecoenvironmental effect and the relationships with soil organic carbon (SOC) were analyzed in present experiment. The results showed that both active and SOC contents were in order reduced by estuarine wetland, flood plain, and out-of-lake wetland. Pearson correlative analysis indicated that MBC and DOC were positively related to SOC. The lowest ratios of MBC and DOC to SOC in the estuarine wetland suggested that the turnover rate of microbial active carbon pool was fairly low in this kind of wetland. Our results showed that estuarine wetland had a strong carbon sink function, which played important role in reducing greenhouse gas emissions; besides, changes of water condition might affect the accumulation and decomposition of organic carbon in the wetland soils.

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