scholarly journals Insights into the Light Response of Skeletonema marinoi: Involvement of Ovothiol

Marine Drugs ◽  
2020 ◽  
Vol 18 (9) ◽  
pp. 477
Author(s):  
Alfonsina Milito ◽  
Ida Orefice ◽  
Arianna Smerilli ◽  
Immacolata Castellano ◽  
Alessandra Napolitano ◽  
...  

Diatoms are one of the most widespread groups of microalgae on Earth. They possess extraordinary metabolic capabilities, including a great ability to adapt to different light conditions. Recently, we have discovered that the diatom Skeletonema marinoi produces the natural antioxidant ovothiol B, until then identified only in clams. In this study, we investigated the light-dependent modulation of ovothiol biosynthesis in S. marinoi. Diatoms were exposed to different light conditions, ranging from prolonged darkness to low or high light, also differing in the velocity of intensity increase (sinusoidal versus square-wave distribution). The expression of the gene encoding the key ovothiol biosynthetic enzyme, ovoA, was upregulated by high sinusoidal light mimicking natural conditions. Under this situation higher levels of reactive oxygen species and nitric oxide as well as ovothiol and glutathione increase were detected. No ovoA modulation was observed under prolonged darkness nor low sinusoidal light. Unnatural conditions such as continuous square-wave light induced a very high oxidative stress leading to a drop in cell growth, without enhancing ovoA gene expression. Only one of the inducible forms of nitric oxide synthase, nos2, was upregulated by light with consequent production of NO under sinusoidal light and darkness conditions. Our data suggest that ovothiol biosynthesis is triggered by a combined light stress caused by natural distribution and increased photon flux density, with no influence from the daily light dose. These results open new perspectives for the biotechnological production of ovothiols, which are receiving a great interest for their biological activities in human model systems.

2021 ◽  
pp. 1-15
Author(s):  
Haysam M.M.A.M. Ahmed ◽  
Liliana S. Moreira Teixeira

The development of new therapies is tremendously hampered by the insufficient availability of human model systems suitable for preclinical research on disease target identification, drug efficacy, and toxicity. Thus, drug failures in clinical trials are too common and too costly. Animal models or standard 2D in vitro tissue cultures, regardless of whether they are human based, are regularly not representative of specific human responses. Approaching near human tissues and organs test systems is the key goal of organs-on-chips (OoC) technology. This technology is currently showing its potential to reduce both drug development costs and time-to-market, while critically lessening animal testing. OoC are based on human (stem) cells, potentially derived from healthy or disease-affected patients, thereby amenable to personalized therapy development. It is noteworthy that the OoC market potential goes beyond pharma, with the possibility to test cosmetics, food additives, or environmental contaminants. This (micro)tissue engineering-based technology is highly multidisciplinary, combining fields such as (developmental) biology, (bio)materials, microfluidics, sensors, and imaging. The enormous potential of OoC is currently facing an exciting new challenge: emulating cross-communication between tissues and organs, to simulate more complex systemic responses, such as in cancer, or restricted to confined environments, as occurs in osteoarthritis. This review describes key examples of multiorgan/tissue-on-chip approaches, or linked organs/tissues-on-chip, focusing on challenges and promising new avenues of this advanced model system. Additionally, major emphasis is given to the translation of established tissue engineering approaches, bottom up and top down, towards the development of more complex, robust, and representative (multi)organ/tissue-on-chip approaches.


Molecules ◽  
2020 ◽  
Vol 25 (10) ◽  
pp. 2351 ◽  
Author(s):  
Daniel Cervantes-García ◽  
Armida I. Bahena-Delgado ◽  
Mariela Jiménez ◽  
Laura E. Córdova-Dávalos ◽  
Vanessa Ruiz-Esparza Palacios ◽  
...  

Nonsteroidal anti-inflammatory drug (NSAID)-induced enteropathy is considered a serious and increasing clinical problem without available treatment. Glycomacropeptide (GMP) is a 64-amino acid peptide derived from milk κ-casein with numerous biological activities. The aim of this study was to investigate the protective effect of GMP on NSAID enteropathy in rats. Enteropathy was induced by seven days oral indomethacin administration. Rats were orally GMP treated from seven days previous and during the establishment of the enteropathy model. Changes in metabolism, hematological and biochemical blood alterations, intestinal inflammation and oxidative damage were analyzed. Integrity barrier markers, macroscopic intestinal damage and survival rate were also evaluated. GMP treatment prevented anorexia and weight loss in animals. Furthermore, prophylaxis with GMP ameliorated the decline in hemoglobin, hematocrit, albumin and total protein levels. The treatment had no therapeutic efficacy on the decrease of occludin and mucin (MUC)-2 expression in intestinal tissue. However, GMP markedly decreased neutrophil infiltration, and CXCL1, interleukin-1β and inducible nitric oxide synthase expression. Nitric oxide production and lipid hydroperoxide level in the small intestine were also diminished. These beneficial effects were mirrored by preventing ulcer development and increasing animal survival. These results suggest that GMP may protect against NSAID enteropathy through anti-inflammatory and antioxidant properties.


2015 ◽  
Vol 50 (S40) ◽  
pp. S14-S23 ◽  
Author(s):  
Hongmei Mou ◽  
Karissa Brazauskas ◽  
Jayaraj Rajagopal

1997 ◽  
Vol 8 (9) ◽  
pp. 1437-1442
Author(s):  
B Anderstam ◽  
K Katzarski ◽  
J Bergström

Nitric oxide (NO) is involved in blood pressure regulation, and its synthesis is inhibited by methylarginines. It has been hypothesized that one of these, asymmetrical dimethylarginine (ADMA), may contribute to dialysis-associated hypertension because it accumulates in the plasma of hemodialysis (HD) patients in a concentration high enough (4 mumol/L) to inhibit NO synthesis in experimental model systems. A precolumn HPLC technique was used to quantify methylarginines (ADMA and symmetrical dimethylarginine [SDMA]) in plasma from HD patients before and after dialysis, from continuous ambulatory peritoneal dialysis (CAPD) patients, and from healthy subjects. Plasma ADMA concentrations were 0.59 +/- 0.22 (SD) mumol/L in HD patients predialysis (n = 19) and 0.70 +/- 0.27 mumol/L in CAPD patients (n = 11), versus about half of the concentration in control subjects (0.36 +/- 0.08 mumol/L, n = 7). The concentrations of SDMA (not an inhibitor of NO formation) were approximately four to five times the ADMA concentrations in both HD and CAPD patients, in contrast to a ratio of 1:1 in the control subjects. Methylarginine concentrations were reduced by 23% and 40% postdialysis, as calculated from ADMA and SDMA values, respectively. No significant correlations were observed between ADMA concentrations, on the one had, and blood pressure, creatinine and dialysis dose (Kt/V urea), on the other hand. It is concluded that plasma levels of ADMA are considerably lower than those reported earlier in patients treated with HD and also below the levels that hitherto have been thought to have clinical relevance. The role of ADMA in inhibiting NO in dialysis-associated hypertension is questioned.


2005 ◽  
Vol 288 (5) ◽  
pp. L950-L957 ◽  
Author(s):  
Jae W. Lee ◽  
Robert F. Gonzalez ◽  
Cheryl J. Chapin ◽  
Justin Busch ◽  
Jeffrey R. Fineman ◽  
...  

Inhaled nitric oxide (NO) is a selective pulmonary vasodilator effective in treating persistent pulmonary hypertension in newborns and in infants following congenital heart disease surgery. Recently, multiple in vivo and in vitro studies have shown a negative effect of NO on surfactant activity as well as surfactant protein gene expression. Although the relationship between NO and surfactant has been studied previously, the data has been hard to interpret due to the model systems used. The objective of the current study was to characterize the effect of NO on surfactant protein gene expression in primary rat type II pneumocytes cultured on a substratum that promoted the maintenance of type II cell phenotype. Exposure to a NO donor, S-nitroso-N-acetylpenicillamine (SNAP), decreased surfactant protein (SP)-A, (SP)-B, and (SP)-C mRNA levels in type II pneumocytes in a time- and dose-dependent manner. The effect was mediated in part by an increase in endothelin-1 secretion and a decrease in the intracellular messenger, phosphorylated ERK1/2 mitogen-activated protein kinases (MAPK). Exposing type II pneumocytes to endothelin-1 receptor antagonists PD-156707 or bosentan before exposure to SNAP partially prevented the decrease in surfactant protein gene expression. The results showed that NO mediated the decrease in surfactant protein gene expression at least in part through an increase in endothelin-1 secretion and a decrease in phosphorylated ERK1/2 MAPKs.


1998 ◽  
Vol 7 (2) ◽  
pp. 131-140 ◽  
Author(s):  
J McHugh ◽  
DJ Cheek

The endothelial cells of the vascular system are responsible for many biological activities that maintain vascular homeostasis. Responding to a variety of chemical and physical stimuli, the endothelium elaborates a host of vasoactive agents. One of these agents, endothelium-derived relaxing factor, now accepted as nitric oxide, influences both cellular constituents of the blood and vascular smooth muscle. A principal intracellular target for nitric oxide is guanylate cyclase, which, when activated, increases the intracellular concentration of cyclic guanosine monophosphate, which in turn activates protein kinase G. Acting by this pathway, nitric oxide induces relaxation of vascular smooth muscle and inhibits platelet activation and aggregation. Derangements in endothelial production of nitric oxide are implicated as both cause and consequence of vascular diseases, including hypertension, atherosclerosis, and coronary artery disease.


2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
Antonio Muro ◽  
José-Luís Pérez-Arellano

Nitric oxide (NO) is a very simple molecule that displays very important functions both in helminths (mainly those involved in respiratory pathology) and in mammalian hosts. In this paper we review four issues related to interaction of NO and lung helminthic diseases. Firstly, we evaluated data available on the NO synthesis and release by helminths and their biological role. Next, we summarized the effect of antigens obtained from different phases of the biological cycle on NO production by host mammalian cells (mainly from human sources). Thirdly, we revised the evaluation of NO on the biological activities and/or the viability of respiratory helminths. Lastly, the deleterious consequences of increased production of NO during helminthic human infection are detailed.


Cephalalgia ◽  
2013 ◽  
Vol 34 (2) ◽  
pp. 136-147 ◽  
Author(s):  
Roshni Ramachandran ◽  
Deepak Kumar Bhatt ◽  
Kenneth Beri Ploug ◽  
Anders Hay-Schmidt ◽  
Inger Jansen-Olesen ◽  
...  

Background and aim Infusion of glyceryltrinitrate (GTN), a nitric oxide (NO) donor, in awake, freely moving rats closely mimics a universally accepted human model of migraine and responds to sumatriptan treatment. Here we analyse the effect of nitric oxide synthase (NOS) and calcitonin gene-related peptide (CGRP) systems on the GTN-induced neuronal activation in this model. Materials and methods The femoral vein was catheterised in rats and GTN was infused (4 µg/kg/min, for 20 minutes, intravenously). Immunohistochemistry was performed to analyse Fos, nNOS and CGRP and Western blot for measuring nNOS protein expression. The effect of olcegepant, L-nitro-arginine methyl ester (L-NAME) and neurokinin (NK)-1 receptor antagonist L-733060 were analysed on Fos activation. Results GTN-treated rats showed a significant increase of nNOS and CGRP in dura mater and CGRP in the trigeminal nucleus caudalis (TNC). Upregulation of Fos was observed in TNC four hours after the infusion. This activation was inhibited by pre-treatment with olcegepant. Pre-treatment with L-NAME and L-733060 also significantly inhibited GTN induced Fos expression. Conclusion The present study indicates that blockers of CGRP, NOS and NK-1 receptors all inhibit GTN induced Fos activation. These findings also predict that pre-treatment with olcegepant may be a better option than post-treatment to study its inhibitory effect in GTN migraine models.


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