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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).
Glutathione
Published in Ruth G. Alscher, John L. Hess, Antioxidants in Higher Plants, 2017
Alfred Hausladen, Ruth G. Alscher
Glutathione and ascorbate have both been shown to have the potential for an antioxidant role in conjunction with α-tocopherol. Since α-tocopherol is the major free radical scavenger of thylakoid membranes, this finding is of particular relevance for chloroplast metabolism. The direct interaction of α-tocopherol and ascorbate is well established.103 An interactive role for glutathione with membrane constituents was established by Barclay104 in an artificial liposome membrane system where it was shown that glutathione acts to spare the lipid-soluble molecule by lowering the rate of chain initiation of free radical formation. This occurred when peroxidation was initiated in the aqueous phase.
The Water Permeability of Intact Subcellular Organelles
Published in Gheorghe Benga, Water Transport in Biological Membranes, 1989
A second natural organelle that has been subjected to water permeability studies is the thylakoid membrane of chloroplasts. Thylakoid membranes form substructures of surpassing complexity within algal cells and within the chloroplasts of higher plants, where they contain the pigments and electron-transport apparatus of the light reactions of photosynthesis. The topology of these structures is still not completely understood, although the electron microscopic work in serial section of Paolillo and co-workers44–48 has provided considerable structural insight. Basically, the thylakoids are organized as layered stacks of flattened, osmotically tight vesicles (the grana stacks), in which are embedded the pigments and electron transport proteins which catalyze the following reactions:
Characterization of planktonic and biofilm cells from two filamentous cyanobacteria using a shotgun proteomic approach
Published in Biofouling, 2020
Maria João Leal Romeu, Dany Domínguez-Pérez, Daniela Almeida, João Morais, Alexandre Campos, Vítor Vasconcelos, Filipe J. M. Mergulhão
Proteins related to photosystems I and II and with allophycocyanin were found in three of the four biofilm condition groups (Table 1 in dark grey shading). The specific conditions in which these proteins were identified can be found in the Supplementary material, SM5. Photosystem I (PS I, plastocyaninferredoxin oxidoreductase) and photosystem II (PS II, waterplastoquinone oxidoreductase) are multisubunit protein complexes located in the thylakoid membranes of cyanobacteria, algae and higher plants (Nelson and Yocum 2006). Although in the present study the PsaF protein was only identified in biofilms of both the cyanobacterial strains formed at 40 s−1 (Table 1), this protein is also related to photosystems (Photosystem I subunit III). A study performed by Huang et al. (2002) also identified proteins related to photosystems in the plasma membrane of Synechocystis PCC 6803. A proteomic study with different strains of M. aeruginosa showed that the majority of proteins shared among all strains were involved in photosynthesis and respiration (Alexova et al. 2011). Thus, the distribution of protein identification obtained in the present study is typical for cyanobacteria.
Mechanism of long-term toxicity of CuO NPs to microalgae
Published in Nanotoxicology, 2018
Xingkai Che, Ruirui Ding, Yuting Li, Zishan Zhang, Huiyuan Gao, Wei Wang
The PsbO protein is the core protein of OEC and was detected with thylakoid membranes of the treated algae by Western blot. For thylakoid membranes preparation, 50mL algae medium was centrifugated (8000rpm, 5min) and then the supernatants were removed. The remaining algal pellet was homogenized in an ice-cold isolation buffer (100mM sucrose, 50mM HEPES, pH 7.8, 20mM NaCl, 2mM EDTA, and 2mM MgCl2) and filtered through three layers of pledget. The filtrate was centrifuged at 3000g for 10min. The sediments were washed with isolation buffer, re-centrifuged, and finally suspended in an isolation buffer. The thylakoid membrane proteins were then denatured and separated using 12% polyacrylamide gradient gel. The denatured protein complexes in the gel were then electro-blotted to PVDF membranes, probed with PsbO antibody, and visualized by the enhanced chemi-luminescence method.
Still challenging: the ecological function of the cyanobacterial toxin microcystin – What we know so far
Published in Toxin Reviews, 2018
Azam Omidi, Maranda Esterhuizen-Londt, Stephan Pflugmacher
In contrast, some current findings highlight the involvement of MCs in central metabolism. Differences in the proteins related to the carbon and nitrogen metabolism between MC-producing and non-toxic strains provides new insights into the possibility of MCs involvement in the cellular processes. The proximity of MCs to thylakoid membranes and carboxysomes, aside from the evidence of regulation of both toxicity and photosynthesis efficiency by light, suggests a possible role of MCs in photosynthesis and carbon fixation. Identification of binding sites of the nitrogen regulator NtcA in the mcy gene cluster promoter, as well as the dependency of MC synthesis on nitrogen supplies and the carbon/nitrogen status, suggest a possible link between toxicity and primary cellular metabolism.