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Terpenes: A Source of Novel Antimicrobials, Applications and Recent Advances
Published in Mahendra Rai, Chistiane M. Feitosa, Eco-Friendly Biobased Products Used in Microbial Diseases, 2022
Nawal M. Al Musayeib, Amina Musarat, Farah Maqsood
Terpenes of higher order showed increased thermotolerance. The thylakoid membrane permeability increases at higher temperatures due to increased cyclic photophosphorylation in photosystem II (Singsaas 2000). The continuous rise in temperature, the photophosphorylation system loses its ability to stop protons leaking, that resulted in a decrease of transmembrane gradient and ATP synthesis. All these events can potentially cause lowering in the Rubisco activation state due to an inhibition of RuBP regeneration (Friedman et al. 2006). They possess psychoactive effects and are used against various infectious diseases (Lewis and Haba 2019). The antimicrobial properties of some terpenoids are listed in Table 12.2. Chemical structures of some important terepenes and terpenoids (Fig. 12.1).
The Multi-Regulatory Properties of Melatonin in Plants
Published in Akula Ramakrishna, Victoria V. Roshchina, Neurotransmitters in Plants, 2018
Marino B. Arnao, Josefa Hernández-Ruiz
Melatonin also improves the induced-senescence process, and it has been reported that barley leaves treated with melatonin delay dark-induced senescence in a concentration-dependent manner, slowing down chlorophyll loss in detached leaves (Arnao and Hernández-Ruiz, 2009c). This protective effect was confirmed in other species such as apple, cucumber, rice, pea, ryegrass, and Arabidopsis (Table 5.4) and has been related with the protective effect that melatonin has on photosynthetic pigments (chlorophylls and carotenoids), enhancing photosynthetic efficiency in chloroplastic photosystems and alleviating the photoinhibition caused by abiotic stressors (Arnao and Hernández-Ruiz, 2014a, 2015a). In a recent paper, melatonin-treated tomato seedlings showed an increase in the effective quantum yield of Photosystem II, the photochemical quenching coefficient and the proportion of open PSII centers that control plants under saline conditions. In this way, damage to the photosynthetic electron transport chain in Photosystem II was mitigated. In addition, melatonin pretreatment facilitated the repair of PSII by maintaining the availability of D1 protein that was otherwise reduced by salinity (Zhou et al., 2016b).
Overcoming Chronic and Degenerative Diseases with Energy Medicine 1
Published in Aruna Bakhru, Nutrition and Integrative Medicine, 2018
While this might at first seem to be a preposterous idea, there is abundant supporting evidence from the literature of plant physiology. Specifically, red and blue-green algae have intricate light-absorbing structures called phycobilisomes. These “antenna” complexes contain many alpha helical regions, and are described as “light pipes” funneling excitation energy (photons) into the reaction centers of chlorophyll a of photosystem II. Chlorophyll a, in turn, is another membrane protein with five trans-membrane helices (Deisenyhofer Michel and Huber 1985). It is thought that this arrangement enables the algae to survive in weak light environments. The arrangement permits 95% efficiency of energy transfer, as reviewed by Glazer (1985). Moreover, the light sensitive pigment in the human eye, rhodopsin, is also a seven-trans-membrane-helix. Finally, there is evidence for electromagnetic fields acting as first messengers for activating cellular processes without mediation of “second messengers”
Influence of abiotic conditions on the biofouling formation of flagellated microalgae culture
Published in Biofouling, 2022
Lucía García-Abad, Lorenzo López-Rosales, María del Carmen Cerón-García, Marta Fernández-García, Francisco García-Camacho, Emilio Molina-Grima
In addition, the photosynthetic efficiency of Photosystem II (Fv/Fm) for the freely suspended cells in the culture was monitored to gauge the ‘health condition’ of the cells. A decrease in this parameter could indicate thermal and light stress, or be due to a lack (or excess) of nutrients, among other things (Parkhill et al. 2001). To measure photosynthetic efficiency, a fluorimeter (PAM-2500 chlorophyll fluorimeter, Heinz Walz GmbH) was used along with the methodology described by López-Rosales et al. (2014). One millilitre from each vessel was taken every two days to measure the biomass concentration and photosynthetic efficiency in triplicate. Each sample was analysed individually, thus, the data for each condition were reported as the mean value (n = 6) ± the standard deviation.
Evaluation of the environmental impact of magnetic nanostructured materials at different trophic levels
Published in Nanotoxicology, 2021
Roberto Carlos Valerio-García, Iliana E. Medina-Ramírez, Mario A. Arzate-Cardenas, Ana Laura Carbajal-Hernández
As a result of the sub-inhibitory exposure of P. subcapitata to the MNMs-CIT, a decrease in cell density and morphological alterations were registered. The presence of atypical cells (elongated and ‘S’ shaped cells), inflamed and with arrested cell division, was evident, mainly in the highest concentrations of MNMs-CIT tested. Barhoumi and Dewez (2013) reported that the Fe3O4 NPs affected cell division in C. vulgaris due to the high production of reactive oxygen species and the deterioration of the photochemical activity of the photosystem II. An excess of iron within the cell can react with reactive oxygen species (ROS) produced as a result of cellular respiration (via Fenton and Haber –Weiss reactions) and cause damage to proteins, membrane lipids and photosynthetic components (Wang et al. 2013), thus affecting the stability of the membrane and the physiological processes of the microalgae, which leads to morphological damage and division mechanisms (Rana et al. 2020), effects that we could observe in P. subcapitata exposed to MNMs-CIT.
Erythema multiforme following exposure to the herbicide atrazine
Published in Baylor University Medical Center Proceedings, 2021
Madeline Frizzell, Nhan M. Nguyen, Sonal A. Parikh, Maya Sinai, Leonard Goldberg
Atrazine is a triazine drug, belonging to a class of nitrogen-containing heterocycles. It works by binding to plastoquinone-binding protein in photosystem II, a protein that animals lack, and thereby inhibiting the electron transport process.9 The plant dies as a result of photosynthesis inhibition.9 A study to assess the percutaneous absorption of atrazine in human skin found that 16.4% of the applied dose was absorbed, indicating its permeability potential.10 Many anticonvulsants also contain aromatic amine structures like atrazine and are well-known causes of erythema multiforme and Stevens-Johnson syndrome. Lamotrigine, phenytoin, and carbamazepine all contain aromatic amine groups, which have been more commonly related than others to the development of Stevens-Johnson syndrome and toxic epidermal necrolysis.11 However, the relationship between the aromatic amine structure and the development of these hypersensitivity disorders is not understood.11