Beneficial Lactic Acid Bacteria
K. Balamurugan, U. Prithika in Pocket Guide to Bacterial Infections, 2019
The proteolytic system of LAB provides amino acids essential for bacterial growth by protein conversion. It is also engaged in generation of flavor compounds, accounting for the development of organoleptic properties of fermented food (Liu et al. 2010). Two major pathways convert amino acids to flavor compounds: elimination reactions catalyzed by lyases and pathways initiated by aminotransferases. Lyases take part in the production of methanethiol from methionine, while aminotransferases convert amino acids to corresponding α-keto acids. The α-keto acids are key intermediates in aroma generation and can be further transformed into other compounds: α-hydroxyacids, acetyl-CoA derivatives, and aldehydes while the latter turn into alcohols and carboxylic acids (Steele et al. 2013). The proteolytic system of LAB contains cell wall–bound proteinase degrading milk proteins into oligopeptides, peptide transporters transferring peptides into the cell, and various intracellular peptidases breaking down the peptides into shorter peptides and amino acids (Liu et al. 2010).
Renal System
David Sturgeon in Introduction to Anatomy and Physiology for Healthcare Students, 2018
The colour, clarity and odour of urine can provide a great deal of information about a person’s general state of health. Normal urine is typically transparent and ranges in colour from pale yellow to bright amber. Lack of colour is usually not a concern but may indicate excessive fluid consumption or diabetes insipidus (see above). Red or pinkish urine, on the other hand, suggests the presence of blood (haematuria). However, it is important to remember that certain foods such as beetroot and blackberries contain a red pigment which could be responsible for this change in colour. It is also important to discretely enquire whether menstrual blood could have coloured the sample. Cloudy urine often indicates urinary tract infection (UTI) and may contain white blood cells, bacteria, pus and large amounts of mucous. A foamy or frothy specimen is usually a sign of protein in the urine. If you have ever beaten eggs in a bowl and then washed it under a tap, you will have seen it froth and foam as protein from the eggs react with water. A slight odour is not uncommon in a normal urine specimen but strong or foul-smelling urine usually indicates that the sample is highly concentrated or infected. A sweet or fruity odour (acetone), on the other hand, is associated with ketone formation (see below) which may occur as a result of diabetes mellitus, starvation or dehydration. Some foods such as asparagus can also produce strong smelling urine. In this instance, what you can smell is the breakdown of a sulphur compound called methyl mercaptan or methanethiol. There is also a rare genetic condition called trimethylaminuria (fish odour syndrome) which causes urine, sweat and breath to smell strongly of fish.
Biogeneration of Volatile Organic Compounds in Microalgae-Based Systems
Gokare A. Ravishankar, Ranga Rao Ambati in Handbook of Algal Technologies and Phytochemicals, 2019
In microalgae-based systems, the most important biogenic volatile sulfide produced is dimethylsulphide (DMS) (Watson et al. 2016). Microbial catabolism of the dimethylsulphoniopropionate (DMSP) is thought to be the major biological process generating the volatile compound (Carrión et al. 2015). The DMSP arises from the sulfur-containing amino acid methionine, initially from the enzymatic action of methionine decarboxylase and subsequently undergoes decarboxylation, oxidation, and methylation reactions to yield the final product. The demethiolation of DMSP leads to methanethiol which can be converted to DMS by methylation (Achyuthan et al. 2017; Curson et al. 2017).
Development of sodium tetrathionate as a cyanide and methanethiol antidote
Published in Clinical Toxicology, 2022
Adriano Chan, Jangwoen Lee, Subrata Bhadra, Nesta Bortey-Sam, Tara B. Hendry-Hofer, Vikhyat S. Bebarta, Sari B. Mahon, Matthew Brenner, Brian Logue, Renate B. Pilz, Gerry R. Boss
In addition to reacting directly with cyanide, we hypothesized that tetrathionate could also react with methanethiol, another toxic chemical that like cyanide, inhibits cytochrome c oxidase of the mitochondrial electron transport chain [13–16]. Methanethiol, also known as methyl mercaptan and mercaptothiol, is a catabolic product of methionine and is generated during the decay of organic matter [17]. It is present in sewage treatment plants, wood pulp mills, oil and natural gas processing plants, and factories that produce pesticides, poultry feed, and jet fuel [18,19]. Seven deaths related to methanethiol exposure have occurred from occupational exposures over the last 10 years, and like cyanide, methanethiol is listed as a high priority chemical threat by the US Agency for Toxic Substances and Disease Registry [20,21]. But, unlike cyanide, no specific antidote exists for methanethiol.
Agonist of stimulator of interferon genes as antitumor agents: a patent review (2008-2020)
Published in Expert Opinion on Therapeutic Patents, 2021
Nan-Nan Chen, Han Zhang, Qi-Dong You, Xiao-Li Xu
In 2020, Jin Li et al. from HitGen Inc. designed and evaluated the biological activity of diABZIs analogues with a thiazole ring. The exemplary compound 64] showed moderate binding activity to STING with a Kd value of greater than 1 μM and less than 10 μM, yet it had an extremely significant effect on inducing IFN-β and CXCL10 with an EC50 value of less than 10 nM. Particularly, the experimental data showed that the binding affinity and inducing activity were maintained even if methoxy group was replaced with a methanethiol moiety, which was exemplified by compound 80 [60] In the follow-up study of GSK, researchers published a patent of WO2019069270 on the structural optimization of a linker between the two moieties of ABZI [68] Notably, a higher binding affinity could be attained by introducing the methoxy group (compound 81) into the alkane chain relative to introducing fluorine atoms (compound 82). It is worth mentioning that the exemplary compounds could act as either agonists or inhibitors.
Intramuscular cobinamide as an antidote to methyl mercaptan poisoning
Published in Inhalation Toxicology, 2021
Tara B. Hendry-Hofer, Patrick C. Ng, Alison M. McGrath, Kirsten Soules, David S. Mukai, Adriano Chan, Joseph K. Maddry, Carl W. White, Jangwoen Lee, Sari B. Mahon, Matthew Brenner, Gerry R. Boss, Vikhyat S. Bebarta
Methyl mercaptan, also known as methanethiol, is produced endogenously in animals and humans during the metabolism of methionine and cysteine, and is released by oral and intestinal microflora during anaerobic metabolism (Tomei Torres 2014). It is present in a variety of occupational settings, most notably the petroleum, paper and plastic industries, and during the manufacturing of pesticides (Tomei Torres 2014). It has a noxious rotten cabbage odor, and is added to natural gas to aide in leak detection (Tomei Torres 2014). Exposure to high concentrations of methyl mercaptan can lead to nasopharyngeal irritation, headache, vomiting, dizziness, muscle fatigue, hypotension, seizures, coma, cardiac arrhythmias, bronchospasm, pulmonary edema, hepatic and renal damage, and death (Kangas et al. 1986; Klingberg et al. 1988; ATSDR, 1992; Kauppinen et al. 1997; Sato et al. 2003; Korhonen et al. 2004; Tomei Torres 2014; Xiang et al. 2017). In 2014 four employees died after ∼24,000 pounds of methyl mercaptan were released from a pesticide production facility in La Porte, Texas (CSB 2014). Mass casualty exposures from industrial accidents remain an ongoing risk (Song 2016).
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