scholarly journals Quantitative effects of environmental variation on stomatal anatomy and gas exchange in a grass model

2021 ◽  
Author(s):  
Tiago DG Nunes ◽  
Magdalena W Slawinska ◽  
Heike Lindner ◽  
Michael T Raissig
Keyword(s):  
Gas Exchange ◽  
Anatomical Variation ◽  
Brachypodium Distachyon ◽  
Carbon Assimilation ◽  
Light Response ◽  
Gas Analysis ◽  
Environmental Signals ◽  
Grass Model ◽  
Kinetics Of

Stomata are cellular pores on the leaf epidermis that allow plants to regulate carbon assimilation and water loss. Stomata integrate environmental signals to regulate pore apertures and optimize gas exchange to fluctuating conditions. Here, we quantified intraspecific plasticity of stomatal gas exchange and anatomy in response to seasonal variation in Brachypodium distachyon. Over the course of two years we (i) used infrared gas analysis to assess light response kinetics of 120 Bd21-3 wild-type individuals in an environmentally fluctuating greenhouse and (ii) microscopically determined the seasonal variability of stomatal anatomy in a subset of these plants. We observed systemic environmental effects on gas exchange measurements and remarkable intraspecific plasticity of stomatal anatomical traits. To reliably link anatomical variation to gas exchange, we adjusted anatomical gsmax calculations for grass stomatal morphology. We propose that systemic effects and variability in stomatal anatomy should be accounted for in long-term gas exchange studies.

scholarly journals EndOxy: Dynamic Long-Term Evaluation of Endothelialized Gas Exchange Membranes for a Biohybrid Lung

2019 ◽  
Vol 48 (2) ◽  
pp. 747-756 ◽  
Author(s):  
Sarah Klein ◽  
Felix Hesselmann ◽  
Suzana Djeljadini ◽  
Tanja Berger ◽  
Anja Lena Thiebes ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Gas Exchange ◽  
Umbilical Vein ◽  
Blood Gas Analysis ◽  
Gas Analysis ◽  
Gas Transfer ◽  
Exchange Performance ◽  
Porcine Blood ◽  
Short Term Exposure

AbstractIn the concept of a biohybrid lung, endothelial cells seeded on gas exchange membranes form a non-thrombogenic an anti-inflammatory surface to overcome the lacking hemocompatibility of today’s oxygenators during extracorporeal membrane oxygenation. To evaluate this concept, the long-term stability and gas exchange performance of endothelialized RGD-conjugated polydimethylsiloxane (RGD-PDMS) membranes was evaluated. Human umbilical vein endothelial cells (ECs) were cultured on RGD-PDMS in a model system under physiological wall shear stress (WSS) of 0.5 Pa for up to 33 days. Gas exchange performance was tested with three biological replicates under elevated WSS of 2.5 Pa using porcine blood adjusted to venous values following ISO 7199 and blood gas analysis. EC morphology was assessed by immunocytochemistry (n = 3). RGD-PDMS promoted endothelialization and stability of endothelialized membranes was shown for at least 33 days and for a maximal WSS of 2.5 Pa. Short-term exposure to porcine blood did not affect EC integrity. The gas transfer tests provided evidence for the oxygenation and decarboxylation of the blood across endothelialized membranes with a decrease of transfer rates over time that needs to be addressed in further studies with larger sample sizes. Our results demonstrate the general suitability of RGD-PDMS for biohybrid lung applications, which might enable long-term support of patients with chronic lung failure in the future.

scholarly journals Serotonin-dependent kinetics of bursts of feeding underlie a graded response to food availability

2016 ◽  
Author(s):  
Kyung Suk Lee ◽  
Shachar Iwanir ◽  
Ronen B Kopito ◽  
Monika Scholz ◽  
David Biron ◽  
...  
Keyword(s):  
High Rate ◽  
Environmental Signals ◽  
C Elegans ◽  
Food Uptake ◽  
Obesity And Diabetes ◽  
Graded Response ◽  
Environmental Bacteria ◽  
Underlying Mechanisms ◽  
Kinetics Of

AbstractAnimals integrate physiological and environmental signals to modulate their food uptake. Failure to regulate feeding may have devastating results, including obesity and diabetes, underscoring the importance of understanding its underlying mechanisms. The nematode C. elegans, whose food uptake consists of pumping bacteria from the environment into the gut, provides excellent opportunities for discovering principles of conserved regulatory mechanisms. Here we show that worms implement a graded feeding response to the concentration of environmental bacteria by modulating a commitment to bursts of fast pumping. Using long-term, high-resolution, longitudinal recordings of feeding dynamics under defined conditions, we find that the frequency and duration of pumping bursts increase and the duration of long pauses diminishes in environments richer in bacteria. The bioamine serotonin, a known feeding regulator in metazoa, is required for food-dependent induction of bursts as well as for maintaining their high rate of pumping through two distinct mechanisms. Following this phenotype quantitatively we identify the essential serotonergic neurons and the differential roles of distinct families of serotonin receptors. We propose that regulation of bursts is a conserved mechanism of behavior and motor control.

Comparative Labelling and Biokinetic Studies of 99mTc-EDTA(Sn) and 99mTc-DTPA(Sn)

1977 ◽  
Vol 16 (01) ◽  
pp. 30-35 ◽  
Author(s):  
N. Agha ◽  
R. B. R. Persson
Keyword(s):  
Complex Formation ◽  
Significant Influence ◽  
Room Temperature ◽  
Ph Value ◽  
Maximum Activity ◽  
Reduction Step ◽  
Labelling Yield ◽  
Different Temperatures ◽  
Kinetics Of

SummaryGelchromatography column scanning has been used to study the fractions of 99mTc-pertechnetate, 99mTcchelate and reduced hydrolyzed 99mTc in preparations of 99mTc-EDTA(Sn) and 99mTc-DTPA(Sn). The labelling yield of 99mTc-EDTA(Sn) chelate was as high as 90—95% when 100 μmol EDTA · H4 and 0.5 (Amol SnCl2 was incubated with 10 ml 99mTceluate for 30—60 min at room temperature. The study of the influence of the pH-value on the fraction of 99mTc-EDTA shows that pH 2.8—2.9 gave the best labelling yield. In a comparative study of the labelling kinetics of 99mTc-EDTA(Sn) and 99mTc- DTPA(Sn) at different temperatures (7, 22 and 37°C), no significant influence on the reduction step was found. The rate constant for complex formation, however, increased more rapidly with increased temperature for 99mTc-DTPA(Sn). At room temperature only a few minutes was required to achieve a high labelling yield with 99mTc-DTPA(Sn) whereas about 60 min was required for 99mTc-EDTA(Sn). Comparative biokinetic studies in rabbits showed that the maximum activity in kidneys is achieved after 12 min with 99mTc-EDTA(Sn) but already after 6 min with 99mTc-DTPA(Sn). The long-term disappearance of 99mTc-DTPA(Sn) from the kidneys is about five times faster than that for 99mTc-EDTA(Sn).

The Effects of Drought on Leaf Gas Exchange and Growth of Three Species of Herbaceous Perennials

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 540a-540
Author(s):  
K.J. Prevete ◽  
R.T. Fernandez
Keyword(s):  
Drought Stress ◽  
Stomatal Conductance ◽  
Gas Exchange ◽  
Drought Tolerance ◽  
Transpiration Rate ◽  
Leaf Gas Exchange ◽  
Gas Analysis ◽  
Herbaceous Perennials ◽  
Effects Of Drought ◽  
Analysis System

Three species of herbaceous perennials were tested on their ability to withstand and recover from drought stress periods of 2, 4, and 6 days. Eupatorium rugosum and Boltonia asteroides `Snowbank' were chosen because of their reported drought intolerance, while Rudbeckia triloba was chosen based on its reported drought tolerance. Drought stress began on 19 Sept. 1997. Plants were transplanted into the field the day following the end of each stress period. The effects of drought on transpiration rate, stomatal conductance, and net photosynthetic rate were measured during the stress and throughout recovery using an infrared gas analysis system. Leaf gas exchange measurements were taken through recovery until there were no differences between the stressed plants and the control plants. Transpiration, stomatal conductance, and photosynthesis of Rudbeckia and Boltonia were not affected until 4 days after the start of stress. Transpiration of Eupatorium decreased after 3 days of stress. After rewatering, leaf gas exchange of Boltonia and Rudbeckia returned to non-stressed levels quicker than Eupatorium. Growth measurements were taken every other day during stress, and then weekly following transplanting. Measurements were taken until a killing frost that occurred on 3 Nov. There were no differences in the growth between the stressed and non-stressed plants in any of the species. Plants will be monitored throughout the winter, spring, and summer to determine the effects of drought on overwintering capability and regrowth.

Obstructive uropathy in the context of ureteroinguinal hernia: experience of challenges in surgical management of an unwell patient

2020 ◽  
Vol 13 (8) ◽  
pp. e235060
Author(s):  
Mitchell Egerton Barns ◽  
Arvind Vasudevan ◽  
Emma Lucy Marsdin
Keyword(s):  
Obstructive Uropathy ◽  
Anatomical Variation ◽  
Surgical Patients ◽  
Definitive Treatment ◽  
Ureteric Stent ◽  
Common Presentation ◽  
Iatrogenic Damage ◽  
Vesicoureteric Junction ◽  
Collecting System

This case exemplifies an unusual anatomical variation of a common presentation and highlights the importance of perioperative diagnosis and planning in complex surgical patients. A 72-year-old comorbid man presented to the emergency department with an infected obstructed right kidney secondary to an obstructing 12 mm vesicoureteric junction calculi. However, imaging also showed concurrent ureteroinguinal hernia associated with a 130 cm-long ureter, too long for conventional treatment with a ureteric stent. Acutely, the patient’s collecting system was decompressed via nephrostomy, but due to the rarity of this anatomical variation, definitive treatment had to be rethought to help reduce the risk of iatrogenic damage and the associated long-term complications.

Long-term liming improves soil fertility and soybean root growth, reflecting improvements in leaf gas exchange and grain yield

2021 ◽  
Vol 128 ◽  
pp. 126308
Author(s):  
João William Bossolani ◽  
Carlos Alexandre Costa Crusciol ◽  
José Roberto Portugal ◽  
Luiz Gustavo Moretti ◽  
Ariani Garcia ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Root Growth ◽  
Soil Fertility ◽  
Grain Yield ◽  
Leaf Gas Exchange ◽  
Soybean Root

scholarly journals Automated Microscopy: Macro Language Controlling a Confocal Microscope and its External Illumination: Adaptation for Photosynthetic Organisms

2016 ◽  
Vol 22 (2) ◽  
pp. 258-263 ◽  
Author(s):  
Gábor Steinbach ◽  
Radek Kaňa
Keyword(s):  
Light Sources ◽  
Light Conditions ◽  
Photosynthetic Organisms ◽  
Automated Microscopy ◽  
Photosynthetic Microorganisms ◽  
Arduino Microcontroller ◽  
Microscopy Data ◽  
Kinetics Of ◽  
Photosynthetic Cells

AbstractPhotosynthesis research employs several biophysical methods, including the detection of fluorescence. Even though fluorescence is a key method to detect photosynthetic efficiency, it has not been applied/adapted to single-cell confocal microscopy measurements to examine photosynthetic microorganisms. Experiments with photosynthetic cells may require automation to perform a large number of measurements with different parameters, especially concerning light conditions. However, commercial microscopes support custom protocols (throughTime Controlleroffered by Olympus orExperiment Designeroffered by Zeiss) that are often unable to provide special set-ups and connection to external devices (e.g., for irradiation). Our new system combining an Arduino microcontroller with theCell⊕Findersoftware was developed for controlling Olympus FV1000 and FV1200 confocal microscopes and the attached hardware modules. Our software/hardware solution offers (1) a text file-based macro language to control the imaging functions of the microscope; (2) programmable control of several external hardware devices (light sources, thermal controllers, actuators) during imaging via the Arduino microcontroller; (3) theCell⊕Findersoftware with ergonomic user environment, a fast selection method for the biologically important cells and precise positioning feature that reduces unwanted bleaching of the cells by the scanning laser.Cell⊕Findercan be downloaded fromhttp://www.alga.cz/cellfinder. The system was applied to study changes in fluorescence intensity inSynechocystissp. PCC6803 cells under long-term illumination. Thus, we were able to describe the kinetics of phycobilisome decoupling. Microscopy data showed that phycobilisome decoupling appears slowly after long-term (>1 h) exposure to high light.

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