Dietary Fibers And Colon Cancer*
Herman Autrup, Gary M. Williams in Experimental Colon Carcinogenesis, 2019
Lignin — This “noncarbohydrate” phenylpropane polymer joined by carbon-car-bon bonds (rather than the glycosidic linkages of polysaccharides) has a molecular weight of about 1000 to 4500. It is highly insoluble and remains after the plant cell wall has been treated with 72% sulfuric acid. Changes in pH along the digestive tract may cause portions of the lignin molecule to be released or altered.14 Although it is unlikely that significant enzymatic digestion of lignin occurs within the intestinal lumen, removal of neighboring carbohydrates may increase the solubility of this polymer.22 The main role of lignin is to provide support to the plant cell wall. In its natural state lignin is closely linked with cellulose and hemicelluloses. Foods with the highest concentration of lignin include some breakfast cereals, followed by fruits and vegetables.22
Plant Phenolics
Ruth G. Alscher, John L. Hess in Antioxidants in Higher Plants, 2017
Regarding transport, monolignols are frequently found in plant tissue as their O-phenolic glucosides, i.e., £"-coniferin 42, E-syringin 43, as well as Z-coniferin 44, Z-syringin 45, and Z-isoconiferin 46 in Fagus sp.17,49,74,78 It is assumed that the glucosides may represent the chemical species being transferred across the plasma membrane into the lignifying wall; action of cell-wall bound β-glucosidases can then regenerate the monolignols which undergo polymerization (see Yamamoto et al.82). The substrate specificity of UDPG:coniferyl alcohol glucosyltransferases is markedly affected by the geometry of the monomer substrate, i.e., in Fagus sp., Z-coniferyl alcohol 40 was the much preferred substrate when compared to its E-analog 37,83 whereas in loblolly pine (Pinus taeda) both Ε and Z-isomers were efficiently utilized.84 The ramification of such substrate specificity with respect to lignification awaits a precise clarification. Alternatively, the glucosides may serve in a storage capacity and be used as needed.82 The precise role of the monolignol glucosides 42-46 will be clarified from the subcellular location of both the UDPG: monolignol glucosyltransferase(s) and their corresponding glucoside 42-46 products.
Materialism and reductionism in science and medicine
R. Paul Thompson, Ross E.G. Upshur in Philosophy of Medicine, 2017
There are two connected but different kinds of reductionism. One is ontological (or entity) reductionism; the other is theory reductionism. Ontological reductionism is the view that every level of phenomena has its causal explanation at a lower level. All the properties of a dining room table are explainable in terms of its molecular structure. Its molecular structure is explainable in terms of the properties of elementary chemicals and the interaction of those chemicals. In turn, the molecules that make up the table and their interaction are explainable in terms of fundamental elements that constitute the molecules. Wood, for example, is mainly composed of cellulose, several hemicelluloses and lignin. The percentages vary slightly depending on the species. By far the highest percentage is cellulose (around 40–45%). Cellulose is composed of the fundamental elements hydrogen, oxygen and carbon (see Figure 4.1).
Nanofibrillated cellulose causes acute pulmonary inflammation that subsides within a month
Published in Nanotoxicology, 2018
Marit Ilves, Sara Vilske, Kukka Aimonen, Hanna K. Lindberg, Saila Pesonen, Irene Wedin, Markus Nuopponen, Esa Vanhala, Casper Højgaard, Jakob R. Winther, Martin Willemoës, Ulla Vogel, Henrik Wolff, Hannu Norppa, Kai Savolainen, Harri Alenius
NFC has attracted interest because of its ability to form strong entangled nanoporous networks. Due to its impressive mechanical reinforcement capability (Xu et al. 2013) and high barrier property, NFC is used in films, nanocomposites, and paper (Lavoine et al. 2012). NFC quality and properties can be altered and improved by enzymatic and chemical pretreatments. These processes aim at degrading lignin and hemicellulose contents, to ease the separation of the cellulose fibrils, or at adding charged groups onto the fiber surface (Fukuzumi et al. 2009; Fukuzumi et al. 2011; Siró et al. 2011; Abdul Khalil et al. 2014). The oxygen barrier properties of functionalized NFC are competitive with fossil-derived synthetic plastics and hence NFC has a great potential to be utilized also as an alternative packaging material (Nair et al. 2014).
A review of pulmonary toxicity studies of nanocellulose
Published in Inhalation Toxicology, 2020
Takafumi Sai, Katsuhide Fujita
Concerning previous reports, it was reported that changes in inflammatory marker levels in BALF and blood differ depending on the surface modification (Ilves et al. 2018) and length (Park et al. 2018) of NC. Specifically, the cause of the different findings was attributed to the aggregability of the fibers due to their different lengths (Yanamala et al. 2014) and interactions with the cell membrane and intracellular molecules due to the different numbers of OH groups on the fiber surface (Hadrup et al. 2019). In addition, several in vitro experiments using lung-derived cells have been reported, and differences in lignin content (Yanamala et al. 2016), aggregability due to differences in NC dispersion (Menas et al. 2017), interfiber interactions in cells due to fiber length (Endes et al. 2015), and surface modification (Jimenez et al. 2017) are mentioned as the causes of different findings. However, in some cases, changes observed in vitro were not reproduced in vivo (Ilves et al. 2018), and the toxicological significance of changes in gene expression and inflammatory marker levels is unknown.
Induced mutation in Agaricus bisporus by gamma ray to improve genetic variability, degradation enzyme activity, and yield
Published in International Journal of Radiation Biology, 2021
Tayebeh Harfi, Motallebi-Azar Alireza, Rasouli Farzad, Zaare-Nahandi Fariborz
According to the lifecycle of the white button mushroom, decreasing the variability is the main obstacle in breeding programs. Thus, the present study unveiled that gamma irradiation could be a useful tool for inducing the variation. Our result showed that mutation by gamma-ray could be effective in creating diversity as an early step for classical and molecular breeding; in other words, the application of gamma-ray treatments on white button mushroom spores created desirable variation in the traits. It can also accidentally result in the isolation of a new strain. The variation of yields observed along with changes in lignin-degrading enzyme activities can indicate that the higher yield is probably due to an enhancement in the enzyme activity. In this research, the isolated 15 variants were clustered in two main groups by the cluster analysis. The cluster I had higher lignin degradation enzyme activity and yield, and genetic variation was approved by the SRAP marker. Finally, our results revealed that gamma irradiation can produce new variants and increase variability for use in the future breeding program.
Related Knowledge Centers
- Calcification
- Cell Wall
- Cellulose
- Chitin
- Phenols
- Polymer
- Carbon
- Homogeneity & Heterogeneity
- Cross-Link
- Sinapyl Alcohol