Biochemical Markers in Ophthalmology
Ching-Yu Cheng, Tien Yin Wong in Ophthalmic Epidemiology, 2022
Metabolites are small molecules or compounds that are either the end or by-product of biochemical reactions in the living cell. Metabolomics is a newly emerging field that extensively analyzes the presence of metabolites in a biological specimen. Although originally metabolites were used to diagnose complex metabolic disease and monogenic disorders such as inborn errors of metabolism [114], it has evolved well beyond the scope of basic clinical chemistry techniques, to include the parallel “quantitative measurement of the dynamic multiparametric metabolic response of living systems to pathophysiological stimuli or genetic modifications” [115]. Metabolomics allows for the accurate analysis of hundreds of metabolites, permitting the characterization of metabolic phenotypes, metabolic derangements that inspire disease, the identification of innovative therapeutic targets, and the detection of biomarkers that may guide treatment and monitor disease progression [116].
Metabolomics of Microbial Biofilms
Chaminda Jayampath Seneviratne in Microbial Biofilms, 2017
Metabolites are low molecular weight intermediates or end-products of enzyme-catalysed reactions in a cell. These molecules perform important structural and functional roles either within the cells or after secretion from the cells. Accordingly, metabolites can be classified as either primary or secondary metabolites. Molecules that are produced actively during growth phase and are essential for growth and development are known as primary or central metabolites. Examples of primary metabolites include alcohols such as ethanol and amino acids. Molecules that are not vital for growth and development but having specialised functions in the overall survivability and adaptability of the organism are known as secondary metabolites. Examples of secondary metabolites include antibiotics, pigments and second-messenger signalling molecules. Some of the secondary metabolites, such as antibiotics, help in competitive survival of the microorganism. These molecules can be used as defence mechanisms against other microbes. Some secondary metabolites also signal for the dormancy state of microbes under unfavourable conditions to promote survival and subsequent release from dormancy on favourable conditions. These metabolites are typically produced during stationary phase in planktonic growth conditions, or in biofilms, and may serve ecological functions [13].
Nanoparticle-Based Delivery of Plant Metabolites
Megh R. Goyal, Hafiz Ansar Rasul Suleria, Ademola Olabode Ayeleso, T. Jesse Joel, Sujogya Kumar Panda in The Therapeutic Properties of Medicinal Plants, 2019
Plants are known to produce compounds (such as alcohols, amino acids, carbohydrates, nucleotides, phytosterols, and some organic acids), which are typically key to the maintenance of normal physiology processes and are important in growth, development, and reproduction. These compounds are called primary metabolites. In contrast, plants also produce secondary metabolites (such as: sterols, terpenes, alkaloids, phenols, tannins, carotenoids, flavonoids, waxes, gums), which are not directly linked to actions that effect the growth, reproduction, and development of the living plant, but seem to have some effect on the function of ecology and the mechanism of defense by production of pigments in some cases [24]. These secondary metabolites are known to be produced from the modification of primary metabolite by enzymatic means. Figure 15.4 shows the pathways to produce some secondary metabolites.
Use of omic technologies in early life gastrointestinal health and disease: from bench to bedside
Published in Expert Review of Proteomics, 2021
Lauren C Beck, Claire L Granger, Andrea C Masi, Christopher J Stewart
The complex, dense, community of microorganisms in the GI tract is also responsible for the production of a number of metabolic compounds [53]. Metabolites are functional small molecules that represent the intermediate or end product of metabolism. They modulate a variety of signaling pathways which facilitate intestinal mucosa homeostasis [53]. The host metabolome is therefore heavily intertwined with and connected to gut microbial communities. Metabolomics is the study of all the metabolites from a given ecosystem, providing insight into the function of the microbiome and the host metabolic profile. Metabolite profiles can differ between healthy and disease subjects in a range of conditions and pathologies, some of which can be detected at unrelated body sites. For instance, the detection of metabolites in urine in relation to conditions that primarily impact the gut or brain. Such detection of metabolic alterations provides targets for noninvasive biomarkers and enables the mechanisms of disease development to be elucidated [21].
Partial least squares regression with compositional response variables and covariates
Published in Journal of Applied Statistics, 2021
Jiajia Chen, Xiaoqin Zhang, Karel Hron
The PLS regression model discussed in the previous section is applied to a data set from metabolomics, where 16 Astragali Radix samples and 16 rats were collected, respectively [19]. This data set thus includes the chemical metabolites of Astragali Radix and the plasma metabolites of rat after giving Astragali Radix. The chemical metabolites consist of two compositional variables: primary metabolites 1. The plasma metabolites and chemical metabolites data sets are given in Appendix A.4.
Blautia—a new functional genus with potential probiotic properties?
Published in Gut Microbes, 2021
Xuemei Liu, Bingyong Mao, Jiayu Gu, Jiaying Wu, Shumao Cui, Gang Wang, Jianxin Zhao, Hao Zhang, Wei Chen
Secondary metabolites are biologically active compounds produced by microorganisms during growth and metabolism and widely used in antibacterial and anticancer drugs, herbicides, and insecticides, which were also an important source of microbial drug development.86,87 According to the categories, there were more than 20 kinds of secondary metabolites, such as polyketides (PKS), non-ribosomal peptides (NRPS), lantipeptides/lantibiotics, bacteriocins, and terpenes.88 As early as 1980, bacteriocins produced by bifidobacteria were reported to possess antibacterial activity against pathogenic microorganisms such as Listeria monocytogenes, Clostridium perfringens, and Escherichia coli.89 Nisin, which is produced by Lactococcus lactis, is used as a natural food preservative.90 According to the chemical structures and mechanisms of action, bacteriocins are divided into four classes, and sactipeptides and lanthipeptides are post-translationally modified antibacterial peptides belonging to class I bacteriocins.91