China
Africa
Explore chapters and articles related to this topic
Removal of Pharmaceutical Pollutants from Municipal Sewage Mediated by Laccases
Published in Peter Grunwald, Pharmaceutical Biocatalysis, 2020
Thomas Hahn, Fabian Haitz, Jan Gajewski, Marius Mohr, Marc Beckett, Susanne Zibek
Ozone plants have higher energy requirements than AC processes, but are often still more economical since the material costs do not apply. Another advantage is that ozonation has been applied in drinking water treatment for many years with good experiences. Experience from municipal sewage treatment plants in Germany and Switzerland shows that ozonation can achieve very good results and that the process can be integrated relatively easily into an existing sewage treatment plant. A disadvantage, however, is that radical scavengers in the wastewater can have a negative effect on the elimination rates. Furthermore, there is a risk that undesirable transformation products will form during the process, which may also be toxic (Zietzschmann et al., 2015). A well-known example is the formation of toxic bromate from the oxidation of bromide (Soltermann et al., 2017). Another aspect is that the dissolved organic carbon (DOC) content of wastewater after ozonation may be higher than before. However, this increase is usually less than 10% (Altmann et al., 2014).
Alcoholic Beverages: Genetic improvement of Yeasts
Published in Yoshikatsu Murooka, Tadayuki Imanaka, Recombinant Microbes for Industrial and Agricultural Applications, 2020
Kenichi Shimizu, Yoichi Yokomori, Kazuyoshi Kitano
Transformation is the process by which naked DNA from the donor organisms is introduced into a recipient cell and incorporated as a part of the inheritable DNA of the host cell. Native DNA transformation has been reported in S. cerevisiae using crude whole-DNA preparations [1-3]. However, since the recombinant DNA technique became available, the recombinant DNA transformation, which uses mainly a purified gene sequence and a plasmid vector, has been employed for construction of novel or improved brewing yeasts. There are two major advantages offered by the technique for yeast improvement: (1) it is possible to introduce any desired genes into yeast if some means of signaling a successful transformation can be devised; (2) genetic characters can be transferred not only from yeasts, but also from other organisms.
Molecular Approaches for Enhancing Abiotic Stress Tolerance in Plants
Published in Hasanuzzaman Mirza, Nahar Kamrun, Fujita Masayuki, Oku Hirosuke, Tofazzal M. Islam, Approaches for Enhancing Abiotic Stress Tolerance in Plants, 2019
Sushma Mishra, Dipinte Gupta, Rajiv Ranjan
As mentioned in Section 23.2.2, plant cells, upon receiving the abiotic stress signal, initiate a signaling cascade that culminates in altering the expression of several stress-responsive genes. Microarray analyses conducted in the model plants Arabidopsis and rice have led to the identification of several stress-inducible genes, some of which have been transformed into crop species and have resulted in significant stress tolerance (Zhang et al., 2004; Umezawa et al., 2006). Apart from altering the levels of functional genes, targeting the expression of regulatory genes like transcription factors (which act upstream to a myriad of functional or single effect genes) is another method of imparting stress tolerance to the crop species. An advantage of this strategy is the ease with which the expression of multiple genes (acting downstream to the regulatory gene) could be altered in a single transformation event. The central drought stress-inducible TFs include ABA-responsive element binding protein (AREBs), NAC (an acronym for NAM, ATAF1-2 and CUC2 myeloblastosis-related proteins [MYBs]) and DREBs. Some of these transcription factors are also involved in salinity response pathway.
Increased removal of cadmium by Chlamydomonas reinhardtii modified with a synthetic gene for γ-glutamylcysteine synthetase
Published in International Journal of Phytoremediation, 2020
René Piña-Olavide, Luz M. T. Paz-Maldonado, M. Catalina Alfaro-De La Torre, Mariano J. García-Soto, Angélica E. Ramírez-Rodríguez, Sergio Rosales-Mendoza, Bernardo Bañuelos-Hernández, Ramón Fernando García De la-Cruz
We explored the removal of cadmium using a transgenic approach aimed to augment its accumulation in C. reinhardtii. There are reports that relate the expression of genes for metallothioneins, peptides, and antioxidants with an increased tolerance to metals and their uptake by C. reinhardtii (Cai et al.1999; Han et al.2008). The chloroplast transformation of C. reinhardtii with vector p463 allowed its cloning by homologous recombination (Dreesen et al.2010). This transformation is efficient and has advantages over a nuclear transformation, including elevated levels of expression and the absence of gene silencing (Staub and Maliga 1995; Quesada-Vargas et al.2005).
Antibiotic resistance in agricultural soils: Source, fate, mechanism and attenuation strategy
Published in Critical Reviews in Environmental Science and Technology, 2022
Jinhua Wang, Lanjun Wang, Lusheng Zhu, Jun Wang, Baoshan Xing
The process of HGT includes transformation, transduction and conjugation (Figure 3a) (Luby et al., 2016). Transformation is uptake of free DNA segments and incorporation into the bacterial chromosome. This DNA can be in the form of plasmids, or chromosomal DNA from dying cells, which is an important reason why ARGs are considered an important contaminant (Luby et al., 2016). Transduction refers as to phage mediated transfer of bacterial DNA between cells, and finally integration into the new bacterial genome (Penadés et al., 2015). Previous researches reported gene transfer by bacteriophages to environmentally relevant antibiotic resistance in wastewater, activated sludge, and soil, suggesting that transduction might be an important mechanism of resistance transfer (Parsley et al., 2010; Colomer-Lluch et al., 2011; Zhao, Ye, et al., 2019). Conjugation refers to transfer of DNA located in plasmid by means of direct cell-cell contact. The F-plasmids of E. coli are certainly a good example of antibiotics resistance spread from one organism to another. (Carattoli et al., 2013; Rozwandowicz et al., 2018). Recently, impacts of soil exotic compounds, such as antibiotics, disinfectants, nanomaterials, ionic liquids, and non-antibiotic pharmaceuticals, on conjugative transfer rates of ARGs between bacteria were evaluated (Baharoglu et al., 2013; Wang, Mao, et al., 2015; Zhang, Gu et al., 2017; Lu et al., 2018). A few studies revealed that metal ions, at concentrations above minimum inhibitory concentrations (MICs), showed decrease in the frequencies of conjugative transfer (Martinez et al., 2006). However, metals (e.g., Cu, Zn, Cr, Ag) in soil are usually present at sub-inhibitory concentrations (below MICs, also referred to as sub-lethal levels), which can promote conjugative transfer of ARGs between E. coli strains (Zhang, Gu, et al., 2018). The mechanisms of this phenomenon were further explored, which involved intracellular reactive oxygen species (ROS) formation, SOS response, increased cell membrane permeability, and altered expression of conjugation-relevant genes (Zhang, Gu, et al., 2018). Consequently, antibiotic resistance can be found in bacteria that acquire the traits through HGT, which might the important reason that transfer ARGs between much more distantly related bacterial species.