Central Integration of Cardiovascular and Respiratory Activity Studied In Situ

2012 ◽  
Keyword(s):  
Respiratory Activity

Respiratory activity, molar growth yields, and ATP content in an Arthrobacter sp. ammonium-limited chemostat culture

1983 ◽  
Vol 29 (9) ◽  
pp. 1136-1140 ◽  
Author(s):  
I. Cacciari ◽  
D. Lippi ◽  
S. Ippoliti ◽  
W. Pietrosanti
Keyword(s):  
Respiratory Activity ◽  
Chemostat Culture ◽  
Morphological Changes ◽  
Sharp Decrease ◽  
Growth Yields ◽  
Atp Content ◽  
Lower Growth ◽  
Wide Range ◽  
Metabolic Activities

Arthrobacter fluorescens was grown in chemostat culture under ammonium-limited conditions and respiratory activity; molar growth yields and ATP content were determined over a wide range of dilution rates. Within a range of dilution rates between 0.10 h−1 and 0.20 h−1, morphological transition occurred, the ratio of cocci to rods appearing inversely related to growth rate. Molar growth yields for both glucose and ammonium decreased with increasing dilution rates because of the higher intracellular polysaccharide content at the lower growth rates. Different metabolic activities were shown in cocci, in rods, and during morphogenesis. A sharp decrease in in situ and potential oxygen quotient (Q(O2)) and in ATP content was observed in the range of dilution rates in which morphological changes occurred.

The gut microenvironment of helicid snails (Gastropoda: Pulmonata): in-situ profiles of pH, oxygen, and hydrogen determined by microsensors

2003 ◽  
Vol 81 (5) ◽  
pp. 928-935 ◽  
Author(s):  
Maryvonne Charrier ◽  
Andreas Brune
Keyword(s):  
Respiratory Activity ◽  
Helix Pomatia ◽  
Distal Intestine ◽  
Biochemical Processes ◽  
Oxygen Gradients ◽  
Uptake Rates ◽  
Cornu Aspersum ◽  
Ph Microelectrodes ◽  
Liquid Ion Exchanger

In-situ profiles of pH, oxygen, and hydrogen were measured in isolated guts of starved terrestrial gastropods belonging to four species, Cornu aspersum (syn. Helix aspersa), Elona quimperiana, Helix pomatia, and Helix lucorum (excepted pH), using Clark-type oxygen and hydrogen microsensors and liquid-ion-exchanger pH microelectrodes. The pH profiles in the two phyllophagous species, H. pomatia and C. aspersum, increased by 0.9 and 1.4 from the crop to the distal intestine (pH 6.4 and 7.4, respectively). In the saprophagous E. quimperiana, as in H. pomatia, the pH along the gut axis remained acidic (5.1–6.6), suggesting saprophagous habits in the latter. In all four species, no oxygen was detected in the gut lumen. Nevertheless, steep oxygen gradients around the gut epithelium indicated high oxygen-uptake rates. The estimated respiratory activity of the intestine ranged between 6.5 (E. quimperiana) and 13.1 (H. lucorum) μmol O2·g fresh mass–1·h–1. Hydrogen accumulated in the intestine and digestive gland of all snails tested, with the highest values in E. quimperiana and H. pomatia (58 and 78 μM, respectively). These results provide the basis for a better understanding of the microbial and biochemical processes involved in digestion.

Airspace structure and mathematical modelling of oxygen diffusion, aeration and anoxia in Eleocharis sphacelata R. Br. Roots

1994 ◽  
Vol 45 (8) ◽  
pp. 1529 ◽  
Author(s):  
BK Sorrell
Keyword(s):  
Root Length ◽  
Oxygen Diffusion ◽  
Apical Meristem ◽  
Respiratory Activity ◽  
Quantitative Description ◽  
Main Axis ◽  
Fine Scale ◽  
Oxygen Release ◽  
Partial Pressures

A quantitative description of the structure of the roots of Eleocharis sphacelata is presented, forming the basis of a mathematical analysis of their aeration via the intercellular airspace system. The mature aerenchymatous roots have cortical porosites as high as 70% and resistances to axial diffusion of 0.015-0.04 Ms mm-3 per mm root length. The corresponding resistance in the younger, non-aerenchymatous tissue just behind the apex is 0.08-0.14 Ms mm-3 per mm, root length. The observed maximum length of the roots (about 0.3 m) is not caused by the oxygen limitations at the apical meristem of the main axis because axial fluxes could theoretically support the meristem in much longer roots. However, the phloem and pericycle of the stele become hypoxic at 0.25 to 0.3 m, suggesting that length could be limited by the need to prevent excessive hypoxia in these tissues. Rates of root oxygen release into the sediment are predicted to be as high as 2.5 �mol h-1 per 0.3-m-long root and higher still for shorter roots. The prevention of anoxia depends greatly on the basal oxygen concentration at the root base: oxygen partial pressures below 8 kPa in the rhizome would cause meristematic anoxia in 0.3 m-long roots. A better resolution of fine-scale variations in respiratory activity in the roots and in the sediment rhizosphere could improve the accuracy of the model, but it does nevertheless indicate that roots of E. sphacelata would normally remain aerobic and significantly oxidize anaerobic sediments in situ.

scholarly journals Effects of Starvation on Physiological Activity and Chlorine Disinfection Resistance in Escherichia coliO157:H7

1998 ◽  
Vol 64 (12) ◽  
pp. 4658-4662 ◽  
Author(s):  
John T. Lisle ◽  
Susan C. Broadaway ◽  
Annette M. Prescott ◽  
Barry H. Pyle ◽  
Colin Fricker ◽  
...  
Keyword(s):  
Respiratory Activity ◽  
Physiological Activity ◽  
Membrane Integrity ◽  
Viable Count ◽  
Starvation Period ◽  
Tetrazolium Chloride ◽  
E Coli ◽  
Chlorine Disinfection ◽  
Significant Difference

ABSTRACT Escherichia coli O157:H7 can persist for days to weeks in microcosms simulating natural conditions. In this study, we used a suite of fluorescent, in situ stains and probes to assess the influence of starvation on physiological activity based on membrane potential (rhodamine 123 assay), membrane integrity (LIVE/DEADBacLight kit), respiratory activity (5-cyano-2,3-di-4-tolyl-tetrazolium chloride assay), intracellular esterase activity (ScanRDI assay), and 16S rRNA content. Growth-dependent assays were also used to assess substrate responsiveness (direct viable count [DVC] assay), ATP activity (MicroStar assay), and culturability (R2A agar assay). In addition, resistance to chlorine disinfection was assessed. After 14 days of starvation, the DVC values decreased, while the values in all other assays remained relatively constant and equivalent to each other. Chlorine resistance progressively increased through the starvation period. After 29 days of starvation, there was no significant difference in chlorine resistance between control cultures that had not been exposed to the disinfectant and cultures that had been exposed. This study demonstrates that E. coli O157:H7 adapts to starvation conditions by developing a chlorine resistance phenotype.

A Clark-type oxygen chip for in situ estimation of the respiratory activity of adhering cells

Talanta ◽  
2010 ◽  
Vol 81 (1-2) ◽  
pp. 228-234 ◽  
Author(s):  
Ching-Chou Wu ◽  
Hsiang-Ning Luk ◽  
Yen-Ting Tsai Lin ◽  
Chia-Yin Yuan
Keyword(s):  
Respiratory Activity

scholarly journals ROS Accumulation and TTC Reduction in Growing Embryo of Crithmum maritimum L. Isolated from Water or Salt Imbibed Seeds

2011 ◽  
Vol 3 (2) ◽  
pp. 98-103 ◽  
Author(s):  
Abdallah ATIA ◽  
Chedly ABDELLY ◽  
Abderrazak SMAOUI
Keyword(s):  
Superoxide Anion ◽  
Anion Radical ◽  
Respiratory Activity ◽  
Superoxide Anion Radical ◽  
Distilled Water ◽  
Tetrazolium Chloride ◽  
Ros Accumulation ◽  
Radicle Emergence ◽  
O2 Production

The salinity induced inhibition of seeds germination remains not clear at physiological levels. The aims of this study is to investigate the effect of salt on germination, embryo growth, superoxide anion radical (O2·-) and the respiratory activity (TTC reduction) in Crithmum maritimum L. seeds. Thus the embryo growth, in situ localization of respiratory activity and superoxide anion radical (O2·-) localization, were investigated. Chlorure 2, 3, 5-triphényltétrazolium (TTC) reduction test and superoxide anion radical (O2·-) localization with Nitroblue Tetrazolium Chloride (NBT) were performed in embryo isolated from seeds of the halophyte Crithmum maritimum L either sown in distilled water or in 200 mM NaCl. The key results show that germination was maximal (90 %) in distilled water, but was fully inhibited following seed exposure to NaCl. The completion of the embryo growth (ca. 2 mm length) leading to the radicle emergence took 6 d in H2O, but was markedly delayed by salt. NaCl reduced the elongation zone in the embryo axis, hence indicating that the cell division and/or cell elongation were disturbed by salinity. The respiratory activity (TTC reduction) and O2·- production in the cotyledon were significantly lowered by salinity.

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