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Electro-Fermentation Technology: Synthesis of Chemicals and Biofuels
Published in Kuppam Chandrasekhar, Satya Eswari Jujjavarapu, Bio-Electrochemical Systems, 2022
Devashish Tribhuvan, V. Vinay, Saurav Gite, Shadab Ahmed
However, recent research has proposed that even in the absence of cytochrome, other redox proteins like ferredoxin (Rnf) and rubredoxin (Rub) can facilitate the electron transfer mechanism (Kracke et al., 2015). In sulfate-reducing bacterial species like Desulfovibrio sp., rubredoxin was reported to function as a redox mediator. In bacteria belonging to Clostridia (Clostridium ljungdahlii, Clostridium pasteurianum, and C. aceticum) and in Sporomusa ovate, ferredoxin was found to serve as a redox mediator (Choi & Sang, 2016).
Conjugated Polyelectrolytes Designed for Biological Applications
Published in John R. Reynolds, Barry C. Thompson, Terje A. Skotheim, Conjugated Polymers, 2019
Pradeepkumar Jagadesan, Yun Huang, Kirk S. Schanze
An ammonium-functionalized, water-soluble CPE with a PPV backbone, 2.3, was synthesized by Huang and coworkers in 2006, and it exhibits an absorption spectrum that extends to 600 nm with a strong fluorescence emission.[9] Polyelectrolyte 2.3 binds very strongly to rubredoxin, a type of anionic iron-sulfur (Fe-S) protein that plays a vital role in various electron transfer processes and enzymatic reactions in biological systems. As a result, rubredoxin quenches the fluorescence of 2.3 (Stern-Volmer quenching constant, KSV = 6.9 × 107 M−1). Thus, 2.3 acts as a sensor for rubredoxin. An earlier reported work by Harrison and coworkers describes the synthesis of a PPP based CPE having ammonium functionality 2.4 via Pd-catalyzed Suzuki coupling. Polyelectrolyte 2.4 has an absorption range extending to 380 nm and displays intense fluorescence emission.[10] Among all the CPEs, 2.4 was the first cationic polyelectrolyte to be utilized to demonstrate the “amplified fluorescence quenching effect” both in solution and as thin films, where the fluorescence intensity of CPE gets quenched by a considerably lower analyte concentration than its monomer analog due to the conjugation in the polymeric backbone. Thus, the sensing is amplified as a result of the “molecular wire effect.” PPP polyelectrolytes having highly quaternized side chains, 2.5, were also reported by Rehahn and coworkers, in which each of the p-phenylene repeating units has four tetraalkylammonium groups.[11] The increased charge on the polymer makes it strongly water-soluble and also renders it with exceptional thermal and chemical stability.
Heavy metal (loid)s phytotoxicity in crops and its mitigation through seed priming technology
Published in International Journal of Phytoremediation, 2023
Rajesh Kumar Singhal, Mahesh Kumar, Bandana Bose, Sananda Mondal, Sudhakar Srivastava, Om Parkash Dhankher, Rudra Deo Tripathi
Jasmonic acid (JA) has a regulatory role in plant growth, development, and stress protection. JA and its active derivatives (jasmonates) modulate a range of defense responses against various stresses (Wasternack 2007). Sharma et al. (2013) discussed the role of JA on photosynthetic pigments and stress markers in pigeon pea seedlings under Cu stress. Sirhindi et al. (2016) noted that Ni toxicity modulates the seedling’s shoot and root weights, chlorophyll content, metabolite, and antioxidant enzymes gene expression in soybean, which could be alleviated by using JA as seed primer. Furthermore, Mir, Sirhindi et al. (2018) depicted the role of JA seed priming in improving growth attributes under Ni toxicity in the soybean. They found that JA improved the antioxidant enzyme, redox status, ROS, and regulated the uptake of Ni. Recently, reported that JA priming declines levels of MDA, O2•−, and H2O2, and decreases membrane and nuclear damage in tomatoes. They also found that RBO (Rubredoxin oxidoreductase) and P-type ATPases transporter genes under Pb stress, which reduce the translocation of Pb in the seedlings. Moreover, JA seed priming improves the photosynthetic activity, ascorbate-glutathione pathway, secondary metabolite, and enhances osmolytes and metal chelating compounds production under Pb stress (Bali, Jamwal, Kaur, et al. 2019; Bali, Jamwal, Kohli, et al. 2019).
A review on bio-functional models of catechol oxidase probed by less explored first row transition metals
Published in Journal of Coordination Chemistry, 2022
Rashmi Rekha Tripathy, Shuvendu Singha, Sohini Sarkar
Iron-containing metalloproteins are numerous in nature. They are known for versatile biophysical applications in living organisms such as humans, plants, animals, arthropods, mollusks and bacteria. Many of them play a significant role in oxygen binding and transport (hemoglobin, hemoerythrin, chlocruorin). Moreover, as electron carriers (rubredoxin) and as electron transfer vectors (cyctchrome) they have other contributions. Iron-containing metalloenzymes like hydrogenase and catalase can participate in many important redox processes occurring in cells, while the first one helps in reversible hydrogen uptake in different microbes, the second one catalyzes dismutation of hydrogen peroxide to water and oxygen. It helps to protect cells from oxidative damage by reactive oxygen species like peroxides [75]. Catechol dioxygenase is another example of an iron-based enzyme which can catalyze oxidation of ortho diphenols (catechols) by oxidative cleavage of a C—C bond present in the phenolic substrates followed by oxygen insertion. Its mechanism is quite different than that of catechol oxidase although both involve oxidation of catechols or catecholic substrates to the corresponding quinones.
Transcriptomic response of Arabidopsis thaliana exposed to hydroxylated polychlorinated biphenyls (OH-PCBs)
Published in International Journal of Phytoremediation, 2019
Srishty Subramanian, Rouzbeh Tehrani, Benoit Van Aken
Looking at the OH-derivatives of 2,5-DCB, we observed that exposure to the most toxic congener, 4′-OH-2,5-DCB, resulted in expression of few specific genes not significantly up- or down-regulated by the two other isomers, 2′-OH-2,5-DCB and 3′-OH-2,5-DCB: among the 40 genes the most overexpressed by exposure to 4′-OH-2,5-DCB, only five were only induced by this compound and not by the two other isomers; four of these genes are involved in response to iron deficiency: transcription factor bHLH100 (AT5G04150, fold change 7.36), transcription factor ORG2 (AT3G51560, fold change 6.29), transcription factor ORG3 (AT3G56980, fold change 5.55), and zinc ion binding protein (AT1G74770, fold change 2.54) (Sivitz et al. 2012; Kobayashi and Nishizawab 2014). This observation is consistent with the enrichment analysis, showing that the two Biological Process categories with the highest enrichment values are cellular response to iron ion starvation (enrichment >100) and iron ion homeostasis (enrichment 27.54). The second gene the most downregulated by exposure to 4′-OH-2,5-DCB (and not by the two other isomers) is a rubredoxin family protein (AT5G17170, fold change 4.28) involved in iron ion binding (Kobayashi and Nishizawab 2014). The reduction of rubredoxin synthesis may constitute an attempt by the plant to limit iron uptake in biological molecules, which would further lower iron availability. Genes involved in iron deficiency and homeostasis were also differentially regulated in response to 2′-OH- and 3′-OH-2,5-DCB, but to a lesser extent, possibly explaining their lower toxicity as compared with 4′-OH-2,5-DCB.