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An Overview of Parasite Diversity
Published in Eric S. Loker, Bruce V. Hofkin, Parasitology, 2023
Eric S. Loker, Bruce V. Hofkin
Additionally, one noteworthy stramenopile (one lacking flagella) is of the genus Blastocystis, for which several subtypes are known, some of which have been recovered from humans and are then referred to as Blastocystis hominis (Figure 2.8A). These organisms have the distinction of colonizing over 1 billion people, making them the most prevalent eukaryotic microbe infecting the human intestine. They are probably transferred between humans and domestic animals and have been implicated in causing diarrhea and nausea. Blastocystis has also been associated with cases of irritable bowel syndrome and may pose problems for immunocompromised people. Their role in causing pathology remains controversial and they are often considered components of a healthy gut microbiome. As with many eukaryotes inhabiting anaerobic or microaerophilic portions of the gut, Blastocystis does not possess conventional mitochondria capable of aerobic respiration. It has a mitochondrion-like organelle that does generate adenosine triphosphate (ATP) but seems intermediate in function between a mitochondrion and a hydrogenosome. The latter is an organelle that generates ATP from pyruvate, while giving off hydrogen (H2) as a by-product. Blastocystis has a hydrogenase enzyme but does not produce H2.
Leveraging Genome Sequencing Strategies for Basic and Applied Algal Research, Exemplified by Case Studies
Published in Gokare A. Ravishankar, Ranga Rao Ambati, Handbook of Algal Technologies and Phytochemicals, 2019
Ariana A. Vasconcelos, Vitor H. Pomin
In this way, the research in photosynthesis has been expanded aiming for the development of methods for the production of photobiological hydrogen in green microalgae such as C. reinhardtii (Melis 2007; Mus et al. 2007; Nguyen et al. 2008). Some studies have demonstrated that it is possible to produce photobiological H2, reducing the size of the light sensing antenna, and inhibiting state transitions and hydrogenase engineering (Hankamer et al. 2007; Melis 2007). In combination with physiological and biochemical approaches, these studies allowed a greater understanding of H2 metabolism and maturation of hydrogenase enzymes in green microalgae. In this context, knowledge of metabolism coupled with genetic tools provides the emergence strategies to optimize the production of H2 eukaryotic photosynthetic organisms (Radakovits et al. 2010).
Vitamins
Published in Frank A. Barile, Barile’s Clinical Toxicology, 2019
Vitamin B3† (nicotinic acid) is a component of nicotinamide adenine dinucleotide (NAD, coenzyme I) and nicotinamide adenine dinucleotide phosphate (NADP, coenzyme II). The two coenzymes catalyze oxidation–reduction reactions that act as electron acceptors and hydrogenases. Niacin is derived from niacinamide or tryptophan and occurs naturally in most red meats, fish, poultry, dairy products, nuts, and vegetables. Niacin deficiency (pellagra, Ital. rough skin) is characterized by dermatitis, dementia, and diarrhea (3Ds). It is often seen in chronic alcoholism, in malabsorption syndrome, and in patients receiving isoniazid (an antituberculosis antibiotic). Pharmacologically, nicotinic acid, but not nicotinamide, is effective in reducing serum lipids. In addition, it triggers peripheral vasodilation and increases blood flow by stimulating histamine release. These properties are distinct from its nutrient role. Consequently, nicotinic acid is useful in the treatment of hypercholesterolemia and hyperlipidemia and in the management of niacin deficiency and pellagra.
Bile acid oxidation by Eggerthella lenta strains C592 and DSM 2243T
Published in Gut Microbes, 2018
Spencer C. Harris, Saravanan Devendran, Celia Méndez- García, Sean M. Mythen, Chris L. Wright, Christopher J. Fields, Alvaro G. Hernandez, Isaac Cann, Phillip B. Hylemon, Jason M. Ridlon
Additional gene clusters encoded by model acetogens, including membrane-spanning electron transport chains such as the Clostridium ljungdahlii proton-translocating ferrodoxin:NAD+ oxidoreductase (Rnf)45 were found in both E. lenta DSM 2243 (Elen_0694-0698) and E. lenta strain C592 (CAB18_RS4340-4360). We located Elen_0690 (3α-HSDH) immediately downstream and within the same operon of the Rnf complex in E. lenta DSM 2243 previously determined to have bile acid 3α-HSDH activity.12 An energy-conserving hydrogenase (Ech)46 was also located in E. lenta DSM 2243 (Elen_1570-1575) and E. lenta strain C592 (CAB18_RS07980-7960). In addition, both strains harbor ATP synthase transmembrane complexes, able to utilize this proton gradient generated from Rnf and Ech complexes to generate ATP from ADP.
Radioprotective effect of atorvastatin against ionizing radiation-induced nephrotoxicity in mice
Published in International Journal of Radiation Biology, 2018
Fereshteh Talebpour Amiri, Maedeh Hamzeh, Ramezan Ali Naeimi, Arash Ghasemi, Seyed Jalal Hosseinimehr
IR generates ROS and imbalances in pro-oxidant/antioxidant status which results in oxidative stress (Bhosle et al. 2005). The excessive production of free radicals with lipid peroxidation induced leakage of cytosolic enzymes such as lactate dehydrogenase, creatinine kinase and phosphatases (Ramadan et al. 1997) and destruction of the cell membrane by lipid peroxidation is an important factor in the development of radiation-induced tissue damage (Valko et al. 2006). Increase of MDA level represented a physiological impairment of the antioxidant status (Karbownik and Reiter 2000). In the present study, the MDA level, as a marker of lipid peroxidation, was increased in irradiated animals. These results are consistent with previous studies (Elkady and Ibrahim 2016; Ismail et al. 2016). In irradiated mice, glutamate de-hydrogenase enzyme increases carbamoyl phosphate synthetase activity and subsequently urea concentration (Ramadan et al. 2001). In this study, IR caused a remarkable increase in the levels of creatinine and urea. Furthermore, the levels of urea and creatinine in irradiated mice pretreated with ATV were significantly decreased when compared with the IR only group. These findings in groups with ATV pretreatment are aligned with the published literature on the antioxidant effects of ATV (Profumo et al. 2014).
Use of clinical chemistry health outcomes and PFAS chain length to predict 28-day rodent oral toxicity
Published in Toxicology Mechanisms and Methods, 2023
Giselle R. M. Bellia, Robert A. Bilott, Ning Sun, David Thompson, Vasilis Vasiliou
Linearity of the variables were tested by calculating the correlation coefficient in R. This study held a requirement of at least a moderate linear relationship between variables at all doses, which is defined as a correlation coefficient of .40. Three of the 15 health outcomes met this assumption: alanine aminotransferase, creatine kinase, and sorbitol dehydrogenase. Homoscedasticity was tested by applying a Breusch-Pagan test to the three remaining health outcomes, with p<.05 indicating heteroscedasticity. Homoscedasticity was seen in two of the three health outcomes: creatine kinase and sorbitol hydrogenase. Values for these variables were normally distributed and it is assumed that there is no relationship between observations (Table 3).