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Adhesion of Bacteria to Solid Surfaces
Published in Girma Biresaw, K.L. Mittal, Surfactants in Tribology, 2019
Nabel A. Negm, Dina A. Ismail, Sahar A. Moustafa, Maram T.H. Abou Kana
Caulobacter crescentus is an attractive illustration of a bacterium species that takes advantage of surface attachment to optimize nutrient uptake. C. crescentus oscillates between stalked cells that adhere tightly to surfaces using a protein holdfast and motile cells that lack this organelle and instead have a polar flagellum. This phenotypic switch makes it possible for cells to adapt to both nutrient-rich (favoring motility) and nutrient-poor (favoring adhesion) environments [60].
Metagenome based analysis of groundwater from arsenic contaminated sites of West Bengal revealed community diversity and their metabolic potential
Published in Journal of Environmental Science and Health, Part A, 2023
Anumeha Saha, Abhishek Gupta, Pinaki Sar
Considering OTUs shared by high As bearing samples (6), a total of 63 OTUs were obtained as core (irrespective of the season), while considering only dry season As bearing samples (4), 152 OTUs were present across the samples (Appendix, File 03; Appendix, Figure 3A). OTUs exclusively present in highest As bearing sample BS20D (considering six As-rich samples) were found to be affiliated to unclassified Alphaproteobacteria-NRL2, unclassified Solimonadaceae, Caulobacter, and Bdellovibrio, mainly. Unclassified OTUs present in abundance in BS20D matched with Minwuiaceae affiliated uncultured clone (denovo 16, 969, and 3022, together comprised 7.97% of the community), earlier reported from perchloroethylene-contaminated groundwater. Also, Solimonadaceae members are known to decompose chemical pollutants and are also presumed to bear As biotransformation (As(V)-reducing and/or As(III)-oxidizing) abilities.[55] A plot indicating major taxa of BS20D is given (Appendix, Figure 3A). The OTUs present only in BS20D among other As bearing samples, their distribution across low/negligible As bearing samples and abundance (irrespective of the season) are summarized in Appendix, File 04.
Optimization of spore laccase production by Bacillus amyloliquefaciens isolated from wastewater and its potential in green biodecolorization of synthetic textile dyes
Published in Preparative Biochemistry & Biotechnology, 2021
Magda A. El-Bendary, Safaa M. Ezzat, Emad A. Ewais, Mohamed A. Al-Zalama
Laccases are distributed in nature and found in plants, insects, fungi, bacteria, and archaea.[3] They play an important role in several metabolic steps, including those involved in fungal pigmentation, plant lignification, lignin biodegradation, humus turnover and cuticle sclerotization.[4] Fungal laccases have many applications in pharmaceuticals, pulp and paper industry. However, fungal laccases works better at low pH and low temperature. Since most industrial processes and biotechnological applications need high temperature, high pHs, solvents, and other harsh conditions, fungal laccases lose their activity and are unsuitable under these conditions. In contrast, bacterial laccases can function more efficiently at high temperature and alkaline pHs.[5] Thus, bacterial laccases are more suitable for industrial applications and bioremediation such as decolorization of industrial textile dyes effluents which considered a major threat worldwide.[6] In 1993, the first bacterial laccase was reported in Azospirulum lipoferum after that laccases have been found in Escherichia coli, Pseudomonas aeruginosa, Pseudomonas syringae, Bacillus subtilis, Mycobacterium tuberculosis, Bordetella compestris, Caulobacter crescentus, and Yersinia pestis.[1] Various bacteria are known to produce laccase extracellularly; however, the discovery of spore laccase of Bacillus species has attracted a lot of scientific and industrial interest. Spore laccase is a spore coat protein derived from spore-forming bacteria which is naturally resistant to harsh physical and chemical conditions such as high temperature, alkaline and acidic pH, ultraviolet radiation, organic solvents, hydrogen peroxide, and other chemical agents.[3,7] The valuable characters of spore laccase make it a promising biocatalyst for industrial applications and waste bioremediation.[8]
Bacillus altitudinis MT422188: a potential agent for zinc bioremediation
Published in Bioremediation Journal, 2022
Maryam Khan, Munazza Ijaz, Ghayoor Abbas Chotana, Ghulam Murtaza, Arif Malik, Saba Shamim
When a bacterial cell encounters a metal ion, its uptake takes place by active or passive uptake system. Active uptake system is a swift and independent system which is driven by a chemiosmotic gradient and does not require cellular ATP. In contrast, passive uptake is a more specific, slower, and ATP-dependent process (Fathollahi et al. 2021). Zinc, second to only Fe is an essential element that is required in many structural cellular enzymes. Owing to less toxicity in bacteria, an accumulation of high tolerance to Zn takes place by active uptake system (Issazadeh et al. 2013). Uptake of Zn2+ ions by bacterial cells is generally coupled with Mg, and both ions are reported to be transported across the cell by a similar mechanism (Cooksey 1993). Zn2+ resistance in B. subtilis is achieved through two general resistance mechanisms; (Moore et al. 2005; Pennella, Arunkumar, and Giedroc 2006) one is mediated by a P-type ATPase efflux system which breaks down ATP to form a phosphorylated compound and the other is mediated by CzcD cation diffusion facilitator type transporter involved in the transport of heavy metal ions (Chandrangsu, Rensing, and Helman 2017). From the RND family, the czrCBA efflux system in Caulobacter crescentus has been reported to enable Cd2+ and Zn2+ egress from the cytoplasm of the bacterial cell (Valencia et al. 2013). In this study, growth curves in the presence and absence of Zn2+ (Figure 8) showed that the growth of bacterial cells declined in the presence of Zn2+, (Figure 2a) and that it acted as stress for B. altitudinis. In the presence of Zn2+ and DNP, the uptake of Zn2+ did not change significantly in the first 7hours. Still, the amount of Zn2+ adsorbed and accumulated intracellularly increased proportionally from 2h to 8h (Figure 2b). In the case of Zn2+ and DCCD, uptake of Zn2+ was affected by DCCD, as the active uptake was slow, but some metal was observed to enter the cell and was adsorbed onto the bacterial cellular surface from 3h to 9h (Figure 2c).