scholarly journals Physiological role of oxygenated cytochrome o: observations on whole-cell suspensions of Vitreoscilla.

1978 ◽  
Vol 135 (1) ◽  
pp. 62-67 ◽  
Author(s):  
D A Webster ◽  
Y Orii
1974 ◽  
Vol 20 (7) ◽  
pp. 943-947 ◽  
Author(s):  
M. Ishaque ◽  
Laszlo Kato

The respiratory chain system of cell suspensions of Mycobacterium lepraemurium was investigated spectrophotometrically. The results obtained indicated that whole cell preparations contained flavins, cytochromes of the a + a3 and b type, as well as two CO-binding pigments; cytochromes a3–CO and a second pigment similar to cytochrome o. The cytochromes were found to be in the reduced form. The presence of cytochrome systems could only be shown after the cell suspensions in the reference cuvette were exposed to oxygen. The positions of the peaks in the difference spectra were similar when the cell suspensions were reduced anaerobically without added substrate or treated with dithionite. The whole cell suspensions of M. lepraemurium were not found to contain detectable quantities of cytochrome c.


2016 ◽  
Vol 147 (5) ◽  
pp. 423-436 ◽  
Author(s):  
Gaspar Peña-Münzenmayer ◽  
Alvin T. George ◽  
Gary E. Shull ◽  
James E. Melvin ◽  
Marcelo A. Catalán

Ae4 (Slc4a9) belongs to the Slc4a family of Cl−/HCO3− exchangers and Na+-HCO3− cotransporters, but its ion transport cycle is poorly understood. In this study, we find that native Ae4 activity in mouse salivary gland acinar cells supports Na+-dependent Cl−/HCO3− exchange that is comparable with that obtained upon heterologous expression of mouse Ae4 and human AE4 in CHO-K1 cells. Additionally, whole cell recordings and ion concentration measurements demonstrate that Na+ is transported by Ae4 in the same direction as HCO3− (and opposite to that of Cl−) and that ion transport is not associated with changes in membrane potential. We also find that Ae4 can mediate Na+-HCO3− cotransport–like activity under Cl−-free conditions. However, whole cell recordings show that this apparent Na+-HCO3− cotransport activity is in fact electroneutral HCO3−/Na+-HCO3− exchange. Although the Ae4 anion exchanger is thought to regulate intracellular Cl− concentration in exocrine gland acinar cells, our thermodynamic calculations predict that the intracellular Na+, Cl−, and HCO3− concentrations required for Ae4-mediated Cl− influx differ markedly from those reported for acinar secretory cells at rest or under sustained stimulation. Given that K+ ions share many properties with Na+ ions and reach intracellular concentrations of 140–150 mM (essentially the same as extracellular [Na+]), we hypothesize that Ae4 could mediate K+-dependent Cl−/HCO3− exchange. Indeed, we find that Ae4 mediates Cl−/HCO3− exchange activity in the presence of K+ as well as Cs+, Li+, and Rb+. In summary, our results strongly suggest that Ae4 is an electroneutral Cl−/nonselective cation–HCO3− exchanger. We postulate that the physiological role of Ae4 in secretory cells is to promote Cl− influx in exchange for K+(Na+) and HCO3− ions.


2012 ◽  
Vol 30 (1) ◽  
pp. 100
Author(s):  
Wei HUANG ◽  
Shi-Bao ZHANG ◽  
Kun-Fang CAO

2018 ◽  
Vol 25 (23) ◽  
pp. 2627-2636 ◽  
Author(s):  
Vincenzo Calderone ◽  
Alma Martelli ◽  
Eugenia Piragine ◽  
Valentina Citi ◽  
Lara Testai ◽  
...  

In the last four decades, the several classes of diuretics, currently available for clinical use, have been the first line option for the therapy of widespread cardiovascular and non-cardiovascular diseases. Diuretic drugs generally exhibit an overall favourable risk/benefit balance. However, they are not devoid of side effects. In particular, all the classes of diuretics cause alteration of potassium homeostasis. <p> In recent years, understanding of the physiological role of the renal outer medullary potassium (ROMK) channels, has shown an intriguing pharmacological target for developing an innovative class of diuretic agents: the ROMK inhibitors. This novel class is expected to promote diuretic activity comparable to (or even higher than) that provided by the most effective drugs used in clinics (such as furosemide), with limited effects on potassium homeostasis. <p> In this review, the physio-pharmacological roles of ROMK channels in the renal function are reported, along with the most representative molecules which have been currently developed as ROMK inhibitors.


2021 ◽  
Vol 22 (11) ◽  
pp. 5575
Author(s):  
Agnieszka Markiewicz ◽  
Dawid Sigorski ◽  
Mateusz Markiewicz ◽  
Agnieszka Owczarczyk-Saczonek ◽  
Waldemar Placek

Caspase-14 is a unique member of the caspase family—a family of molecules participating in apoptosis. However, it does not affect this process but regulates another form of programmed cell death—cornification, which is characteristic of the epidermis. Therefore, it plays a crucial role in the formation of the skin barrier. The cell death cycle has been a subject of interest for researchers for decades, so a lot of research has been done to expand the understanding of caspase-14, its role in cell homeostasis and processes affecting its expression and activation. Conversely, it is also an interesting target for clinical researchers searching for its role in the physiology of healthy individuals and its pathophysiology in particular diseases. A summary was done in 2008 by Denecker et al., concentrating mostly on the biotechnological aspects of the molecule and its physiological role. However, a lot of new data have been reported, and some more practical and clinical research has been conducted since then. The majority of studies tackled the issue of clinical data presenting the role of caspase in the etiopathology of many diseases such as retinal dysfunctions, multiple malignancies, and skin conditions. This review summarizes the available knowledge on the molecular and, more interestingly, the clinical aspects of caspase-14. It also presents how theoretical science may pave the way for medical research. Methods: The authors analyzed publications available on PubMed until 21 March 2021, using the search term “caspase 14”.


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