scholarly journals Role of nutrient concentrations and water movement on diatom’s productivity in culture

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Ida Orefice ◽  
Margherita Musella ◽  
Arianna Smerilli ◽  
Clementina Sansone ◽  
Raghu Chandrasekaran ◽  
...  
Keyword(s):  
Water Movement ◽  
Nutrient Concentrations

scholarly journals The Na+/H+ exchanger isoform 3 is required for active paracellular and transcellular Ca2+ transport across murine cecum

2013 ◽  
Vol 305 (4) ◽  
pp. G303-G313 ◽  
Author(s):  
Juraj Rievaj ◽  
Wanling Pan ◽  
Emmanuelle Cordat ◽  
R. Todd Alexander
Keyword(s):  
Water Movement ◽  
Water Flux ◽  
Wild Type Mouse ◽  
Wild Type ◽  
Rt Pcr ◽  
Ussing Chambers ◽  
Voltage Clamps ◽  
Paracellular Absorption ◽  
Mouse Intestine

Intestinal calcium (Ca2+) absorption occurs via paracellular and transcellular pathways. Although the transcellular route has been extensively studied, mechanisms mediating paracellular absorption are largely unexplored. Unlike passive diffusion, secondarily active paracellular Ca2+ uptake occurs against an electrochemical gradient with water flux providing the driving force. Water movement is dictated by concentration differences that are largely determined by Na+ fluxes. Consequently, we hypothesized that Na+ absorption mediates Ca2+ flux. NHE3 is central to intestinal Na+ absorption. NHE3 knockout mice (NHE3−/−) display impaired intestinal Na+, water, and Ca2+ absorption. However, the mechanism mediating this latter abnormality is not clear. To investigate this, we used Ussing chambers to measure net Ca2+ absorption across different segments of wild-type mouse intestine. The cecum was the only segment with net Ca2+ absorption. Quantitative RT-PCR measurements revealed cecal expression of all genes implicated in intestinal Ca2+ absorption, including NHE3. We therefore employed this segment for further studies. Inhibition of NHE3 with 100 μM 5-( N-ethyl- N-isopropyl) amiloride decreased luminal-to-serosal and increased serosal-to-luminal Ca2+ flux. NHE3−/− mice had a >60% decrease in luminal-to-serosal Ca2+ flux. Ussing chambers experiments under altered voltage clamps (−25, 0, +25 mV) showed decreased transcellular and secondarily active paracellular Ca2+ absorption in NHE3−/− mice relative to wild-type animals. Consistent with this, cecal Trpv6 expression was diminished in NHE3−/− mice. Together these results implicate NHE3 in intestinal Ca2+ absorption and support the theory that this is, at least partially, due to the role of NHE3 in Na+ and water absorption.

scholarly journals A Model Study on the Role of Wetland Zones in Lake Eutrophication and Restoration

2001 ◽  
Vol 1 ◽  
pp. 605-614 ◽  
Author(s):  
J.H. Janse ◽  
W. Ligtvoet ◽  
S. Van Tol ◽  
A.H.M. Bresser
Keyword(s):  
Nutrient Loading ◽  
Predatory Fish ◽  
Nutrient Concentrations ◽  
Fish Stock ◽  
Mixing Rate ◽  
Marsh Vegetation ◽  
Model Calculations ◽  
Critical Loading ◽  
Marsh Area

Shallow lakes respond in different ways to changes in nutrient loading (nitrogen, phosphorus). These lakes may be in two different states: turbid, dominated by phytoplankton, and clear, dominated by submerged macrophytes. Both states are self-stabilizing; a shift from turbid to clear occurs at much lower nutrient loading than a shift in the opposite direction. These critical loading levels vary among lakes and are dependent on morphological, biological, and lake management factors. This paper focuses on the role of wetland zones. Several processes are important: transport and settling of suspended solids, denitrification, nutrient uptake by marsh vegetation (increasing nutrient retention), and improvement of habitat conditions for predatory fish. A conceptual model of a lake with surrounding reed marsh was made, including these relations. The lake-part of this model consists of an existing lake model named PCLake[1]. The relative area of lake and marsh can be varied. Model calculations revealed that nutrient concentrations are lowered by the presence of a marsh area, and that the critical loading level for a shift to clear water is increased. This happens only if the mixing rate of the lake and marsh water is adequate. In general, the relative marsh area should be quite large in order to have a substantial effect. Export of nutrients can be enhanced by harvesting of reed vegetation. Optimal predatory fish stock contributes to water quality improvement, but only if combined with favourable loading and physical conditions. Within limits, the presence of a wetland zone around lakes may thus increase the ability of lakes to cope with nutrients and enhance restoration. Validation of the conclusions in real lakes is recommended, a task hampered by the fact that, in the Netherlands, many wetland zones have disappeared in the past.

Aquaporin water channels and lung physiology

2000 ◽  
Vol 278 (5) ◽  
pp. L867-L879 ◽  
Author(s):  
A. S. Verkman ◽  
Michael A. Matthay ◽  
Yuanlin Song
Keyword(s):  
Water Permeability ◽  
Water Movement ◽  
Alveolar Epithelial Cells ◽  
Minor Effect ◽  
Type I ◽  
Lung Water ◽  
Airway Epithelia ◽  
Lung Physiology ◽  
Osmotic Water

Fluid transport across epithelial and endothelial barriers occurs in the neonatal and adult lungs. Biophysical measurements in the intact lung and cell isolates have indicated that osmotic water permeability is exceptionally high across alveolar epithelia and endothelia and moderately high across airway epithelia. This review is focused on the role of membrane water-transporting proteins, the aquaporins (AQPs), in high lung water permeability and lung physiology. The lung expresses several AQPs: AQP1 in microvascular endothelia, AQP3 in large airways, AQP4 in large- and small-airway epithelia, and AQP5 in type I alveolar epithelial cells. Lung phenotype analysis of transgenic mice lacking each of these AQPs has been informative. Osmotically driven water permeability between the air space and capillary compartments is reduced ∼10-fold by deletion of AQP1 or AQP5 and reduced even more by deletion of AQP1 and AQP4 or AQP1 and AQP5 together. AQP1 deletion greatly reduces osmotically driven water transport across alveolar capillaries but has only a minor effect on hydrostatic lung filtration, which primarily involves paracellular water movement. However, despite the major role of AQPs in lung osmotic water permeabilities, AQP deletion has little or no effect on physiologically important lung functions, such as alveolar fluid clearance in adult and neonatal lung, and edema accumulation after lung injury. Although AQPs play a major role in renal and central nervous system physiology, the data to date on AQP knockout mice do not support an important role of high lung water permeabilities or AQPs in lung physiology. However, there remain unresolved questions about possible non-water-transporting roles of AQPs and about the role of AQPs in airway physiology, pleural fluid dynamics, and edema after lung infection.

scholarly journals Contribution of Internal Nutrients Loading on the Water Quality of a Reservoir

Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1409 ◽  
Author(s):  
Hye Won Lee ◽  
Yong Seok Lee ◽  
Jonggun Kim ◽  
Kyoung Jae Lim ◽  
Jung Hyun Choi
Keyword(s):  
Water Quality ◽  
Sediment Load ◽  
Transport Model ◽  
Three Dimensional ◽  
Algal Growth ◽  
Nutrient Concentrations ◽  
Internal Load ◽  
Phosphorus Flux

Sediment plays an important role in the water quality of a lake by acting as both a nutrient source and sink. The amount of phosphorus and nitrogen in the water depends on the internal load from the sediment as well as the external load. To estimate the effects of sediment load on the water quality of a reservoir, we applied a three-dimensional hydrodynamic and transport model based on the benthic chamber experimental results at Euiam Lake, South Korea. As shown in the sensitivity analysis results, the eutrophication period could be significantly extended by a change of phosphorus flux rates from the sediments. The increased phosphorus flux from the sediments intensifies the algal growth of Euiam Lake, which could cause serious algal bloom during spring and fall. This study provides information on nutrient concentrations in the sediment of Euiam Lake, verifies the role of the sediment as a source or sink of nutrients, and evaluates the effect of sediment release of nutrients and contaminants on water quality. This research is a useful tool in determining the effects of internal load in lakes and establishing the operation guideline for sediment management in order to maintain feasible water quality for beneficial use.

scholarly journals Hydrochemistry in Geothermal Investigations in Iceland Techniques and Applications

1979 ◽  
Vol 10 (2-3) ◽  
pp. 191-224 ◽  
Author(s):  
Stefán Arnórsson
Keyword(s):  
Water Movement ◽  
Areal Extent ◽  
Geothermal Systems ◽  
Environmental Aspects ◽  
Mixing Processes ◽  
Geothermal Exploration ◽  
Flow Mixing ◽  
Surface Exploration ◽  
Exploration Phase

The role of hydrochemistry in geothermal exploration and development is described. During the surface exploration phase hydrochemistry is particularly useful in delineating regional ground-water movement, in estimating underground temperatures, and in mapping the areal extent of geothermal systems. From data obtained through exploratory and investigation, drilling hydrochemistry yields information on the direction of underground geothermal water flow, mixing processes, boiling in the aquifer, and distribution of underground temperatures. It also contributes significantly in defining and solving scaling and corrosion problems and is relevant for environmental aspects of fluid disposal and constructional design.

scholarly journals Menemukan Kembali Aktivisme: Peran Jejaring Sosial pada Gerakan Sanitasi Charity Water

2013 ◽  
Vol 15 (1) ◽  
Author(s):  
Indah Gilang Pusparani
Keyword(s):  
Web 2.0 ◽  
Social Networking ◽  
Social Movement ◽  
Social Networking Sites ◽  
Water Movement ◽  
Social Activism ◽  
The World

Most sanitation movements in the world are physical, local-based, and limited to several beneficiaries in the near proximity of the sanitation project. Social networking sites, such as web 2.0, Facebook, YouTube, and Twitter, help to contribute to the reinvention of social activism, making sanitation movement more accessible and available for everyone despite of geographical constraint. This paper aims to analyze the role of social networking sites in shaping the character, the strategy, and the scope of sanitation movement charity: water, using the concept of social movement and social networks.This paper concludes that social networking sites contribute in shaping the charity: water movement to be platform-based and simpler to every users and activists in term of the character of movement. It shapes its strategy to be the platform to connect and mobilize people from around the world, making it accessible for international activists and beneficiaries. Social networking sites enable activism to reinvent itself.//

Sponge Behavior and the Chemical Basis of Responses: A Post-Genomic View

2019 ◽  
Vol 59 (4) ◽  
pp. 751-764 ◽  
Author(s):  
Sally P Leys ◽  
Jasmine L Mah ◽  
Paul R McGill ◽  
Laura Hamonic ◽  
Fabio C De Leo ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
Atmospheric Pressure ◽  
Water Movement ◽  
Whole Body ◽  
Signal Pathways ◽  
Chemical Signaling ◽  
Electrical Signaling ◽  
Complex Signaling

Abstract Sponges perceive and respond to a range of stimuli. How they do this is still difficult to pin down despite now having transcriptomes and genomes of an array of species. Here we evaluate the current understanding of sponge behavior and present new observations on sponge activity in situ. We also explore biosynthesis pathways available to sponges from data in genomes/transcriptomes of sponges and other non-bilaterians with a focus on exploring the role of chemical signaling pathways mediating sponge behavior and how such chemical signal pathways may have evolved. Sponge larvae respond to light but opsins are not used, nor is there a common photoreceptor molecule or mechanism used across sponge groups. Other cues are gravity and chemicals. In situ recordings of behavior show that both shallow and deep-water sponges move a lot over minutes and hours, and correlation of behavior with temperature, pressure, oxygen, and water movement suggests that at least one sponge responds to changes in atmospheric pressure. The sensors for these cues as far as we know are individual cells and, except in the case of electrical signaling in Hexactinellida, these most likely act as independent effectors, generating a whole-body reaction by the global reach of the stimulus to all parts of the animal. We found no evidence for use of conventional neurotransmitters such as serotonin and dopamine. Intriguingly, some chemicals synthesized by symbiont microbes could mean other more complex signaling occurs, but how that interplay might happen is not understood. Our review suggests chemical signaling pathways found in sponges do not reflect loss of a more complex set.

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