Microbial Responses to Metal Stress, Molecular Mechanisms, Challenges and Implications

A special issue of Microorganisms (ISSN 2076-2607). This special issue belongs to the section "Environmental Microbiology".

Deadline for manuscript submissions: closed (30 September 2021) | Viewed by 14919

Special Issue Editors


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Guest Editor
Department of Genetics, Physiology and Microbiology, Complutense University of Madrid, Madrid, Spain
Interests: microbial responses to stress; metallic nanoparticles; antioxidant responses; autophagy; metal biosensors; metallothioneins

E-Mail Website
Guest Editor
Department of Genetics, Physiology and Microbiology, Complutense University of Madrid, Madrid, Spain
Interests: microbial responses to stress; persistence and survival of pathogens in the environment; role of protists in the ecology and evolution of bacterial pathogens; stress responses and virulence

Special Issue Information

Dear Colleagues,

Metal ions are essential trace elements, but most are toxic in excess amounts. Microorganisms have evolved sophisticated strategies to maintain metal homeostasis, withstand metal toxicity or even use toxic metals to growth. Among others, these mechanisms include metal efflux and reduced uptake, formation of metal complexes and sequestration, reduction of metal ions and activation of antioxidant responses.  Over the last decades, integrated omic technologies are being applied to unravel the genetics and molecular basis underlying metal stress responses in different microbial models. Recently, the field has just started to explore how microorganisms interact with metallic nanoparticles. Knowledge on microbial responses to metals can help us to solve environmental issues. For instance, metal resistant microorganisms can be exploited to clean up metal contaminated sites or monitor metal pollution. However, metal resistance may have serious implications, as some metal tolerance mechanisms appear to contribute to antibiotic resistance in bacteria. This Special Issue aims to address recent advances on the microbial responses to metals and metallic nanoparticles, resistance mechanisms in both prokaryotic and eukaryotic microorganisms, and potential applications on environmental and health-related issues. Research articles and reviews on these topics are welcome.

Prof. Ana Maria Martín-González
Dr. Francisco Amaro
Guest Editors

Manuscript Submission Information

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Keywords

  • Heavy metal stress
  • nanoparticles
  • metal resistance
  • microbial stress responses
  • metal pollution
  • biosensors
  • heavy metal
  • oxidative stress
  • antoioxidants

Published Papers (3 papers)

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Review

31 pages, 2356 KiB  
Review
Unraveling the Underlying Heavy Metal Detoxification Mechanisms of Bacillus Species
by Badriyah Shadid Alotaibi, Maryam Khan and Saba Shamim
Microorganisms 2021, 9(8), 1628; https://doi.org/10.3390/microorganisms9081628 - 30 Jul 2021
Cited by 58 | Viewed by 6135
Abstract
The rise of anthropogenic activities has resulted in the increasing release of various contaminants into the environment, jeopardizing fragile ecosystems in the process. Heavy metals are one of the major pollutants that contribute to the escalating problem of environmental pollution, being primarily introduced [...] Read more.
The rise of anthropogenic activities has resulted in the increasing release of various contaminants into the environment, jeopardizing fragile ecosystems in the process. Heavy metals are one of the major pollutants that contribute to the escalating problem of environmental pollution, being primarily introduced in sensitive ecological habitats through industrial effluents, wastewater, as well as sewage of various industries. Where heavy metals like zinc, copper, manganese, and nickel serve key roles in regulating different biological processes in living systems, many heavy metals can be toxic even at low concentrations, such as mercury, arsenic, cadmium, chromium, and lead, and can accumulate in intricate food chains resulting in health concerns. Over the years, many physical and chemical methods of heavy metal removal have essentially been investigated, but their disadvantages like the generation of chemical waste, complex downstream processing, and the uneconomical cost of both methods, have rendered them inefficient,. Since then, microbial bioremediation, particularly the use of bacteria, has gained attention due to the feasibility and efficiency of using them in removing heavy metals from contaminated environments. Bacteria have several methods of processing heavy metals through general resistance mechanisms, biosorption, adsorption, and efflux mechanisms. Bacillus spp. are model Gram-positive bacteria that have been studied extensively for their biosorption abilities and molecular mechanisms that enable their survival as well as their ability to remove and detoxify heavy metals. This review aims to highlight the molecular methods of Bacillus spp. in removing various heavy metals ions from contaminated environments. Full article
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11 pages, 856 KiB  
Review
Metallic Nanoparticles—Friends or Foes in the Battle against Antibiotic-Resistant Bacteria?
by Francisco Amaro, Álvaro Morón, Silvia Díaz, Ana Martín-González and Juan Carlos Gutiérrez
Microorganisms 2021, 9(2), 364; https://doi.org/10.3390/microorganisms9020364 - 12 Feb 2021
Cited by 38 | Viewed by 3849
Abstract
The rapid spread of antibiotic resistances among bacteria demands novel strategies for infection control, and metallic nanoparticles appear as promising tools because of their unique size and tunable properties that allow their antibacterial effects to be maximized. Furthermore, their diverse mechanisms of action [...] Read more.
The rapid spread of antibiotic resistances among bacteria demands novel strategies for infection control, and metallic nanoparticles appear as promising tools because of their unique size and tunable properties that allow their antibacterial effects to be maximized. Furthermore, their diverse mechanisms of action towards multiple cell components have suggested that bacteria could not easily develop resistance against nanoparticles. However, research published over the last decade has proven that bacteria can indeed evolve stable resistance mechanisms upon continuous exposure to metallic nanoparticles. In this review, we summarize the currently known individual and collective strategies employed by bacteria to cope with metallic nanoparticles. Importantly, we also discuss the adverse side effects that bacterial exposure to nanoparticles may have on antibiotic resistance dissemination and that might constitute a challenge for the implementation of nanoparticles as antibacterial agents. Overall, studies discussed in this review point out that careful management of these very promising antimicrobials is necessary to preserve their efficacy for infection control. Full article
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37 pages, 2579 KiB  
Review
Processing of Metals and Metalloids by Actinobacteria: Cell Resistance Mechanisms and Synthesis of Metal(loid)-Based Nanostructures
by Alessandro Presentato, Elena Piacenza, Raymond J. Turner, Davide Zannoni and Martina Cappelletti
Microorganisms 2020, 8(12), 2027; https://doi.org/10.3390/microorganisms8122027 - 18 Dec 2020
Cited by 32 | Viewed by 4254
Abstract
Metal(loid)s have a dual biological role as micronutrients and stress agents. A few geochemical and natural processes can cause their release in the environment, although most metal-contaminated sites derive from anthropogenic activities. Actinobacteria include high GC bacteria that inhabit a wide range of [...] Read more.
Metal(loid)s have a dual biological role as micronutrients and stress agents. A few geochemical and natural processes can cause their release in the environment, although most metal-contaminated sites derive from anthropogenic activities. Actinobacteria include high GC bacteria that inhabit a wide range of terrestrial and aquatic ecological niches, where they play essential roles in recycling or transforming organic and inorganic substances. The metal(loid) tolerance and/or resistance of several members of this phylum rely on mechanisms such as biosorption and extracellular sequestration by siderophores and extracellular polymeric substances (EPS), bioaccumulation, biotransformation, and metal efflux processes, which overall contribute to maintaining metal homeostasis. Considering the bioprocessing potential of metal(loid)s by Actinobacteria, the development of bioremediation strategies to reclaim metal-contaminated environments has gained scientific and economic interests. Moreover, the ability of Actinobacteria to produce nanoscale materials with intriguing physical-chemical and biological properties emphasizes the technological value of these biotic approaches. Given these premises, this review summarizes the strategies used by Actinobacteria to cope with metal(loid) toxicity and their undoubted role in bioremediation and bionanotechnology fields. Full article
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