Resistance of extremely halophilic archaea to zinc and zinc oxide nanoparticles

Salgaonkar, Bhakti B.; Das, Deepthi; Bragança, Judith M.

doi:10.1007/s13204-015-0424-8

Cited by 15 publications

(7 citation statements)

References 39 publications

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“…The genera Haloferax , Halobacterium , Halorubrum , and Haloarcula were investigated using an agar dilution method, and growth was not inhibited even at the highest tested concentration of 2.5 mM in case of nickel and zinc ions (Nieto et al, 1987). In another study, growth of Halococcus and Haloferax was observed in the presence of up to 2 mM zinc and zinc oxide nanoparticles (Salgaonkar et al, 2015). At salt concentrations of 15% (w/v) NaCl, the toxicity of heavy metals was increased compared to cells grown at high salt concentrations [25% (w/v) NaCl].…”

Section: Discussionmentioning

confidence: 99%

Heavy Metal Ion Stress on Halobacterium salinarum R1 Planktonic Cells and Biofilms

2018

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Halobacterium salinarum R1 is an extremely halophilic archaeon, able to attach to the surface and to form characteristic biofilm structures under physiological conditions. However, the effect of environmental stress factors like heavy metals on biofilms was still unknown. Here, we report on the first insights into H. salinarum biofilm formation when exposed to copper, nickel and zinc and describe the effects of metal ions on the architecture of mature biofilms. We also studied the effects on gene expression in planktonic cells. Investigation of planktonic growth and cell adhesion in the presence of sub-lethal metal concentrations yielded an up to 60% reduced adhesion in case of copper and a significantly enhanced adhesion in case of zinc, whereas nickel treatment had no effect on adhesion. A PMA-qPCR assay was developed to quantify live/dead cells in planktonic cultures and mature biofilms, enabling the investigation of cell vitality after metal exposure. An increased resistance was observed in biofilms with up to 80% in case of copper- and up to 50% in case of zinc exposure compared to planktonic cells. However, nickel-treated biofilms showed no significant increase of cell survival. Microscopic investigation of the architecture of mature biofilms exposed to lethal metal concentrations demonstrated an increased detachment and the formation of large microcolonies after copper treatment, whereas the number of adherent cells increased strongly in nickel-exposed biofilms. In contrast, zinc exposed-biofilms showed no differences compared to the control. Analysis of the expression of genes encoding putative metal transporters by qRT-PCR revealed specific changes upon treatment of the cells with heavy metals. Our results demonstrate diverse effects of heavy metal ions on H. salinarum and imply a metal-specific protective response of cells in biofilms.

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Section: Discussionmentioning

confidence: 99%

Heavy Metal Ion Stress on Halobacterium salinarum R1 Planktonic Cells and Biofilms

2018

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“…However, studies related to the survival and responses of these extreme haloarchaea to nanoparticles are still largely unexplored. Salgaonkar et al (2016) have reported the resistance of haloarchaea to ZnO nanoparticles, however, there are no reports on effect of SNPs on these extremophiles. The present study was an attempt to assess the response of haloarchaea to biosynthesized SNPs and study the possible mechanism of the toxicity of SNPs on the viability of these extremophiles.…”

Section: Discussionmentioning

confidence: 99%

“…The growth was monitored by measuring the absorbance at 600 nm every 24 h using UV-Vis spectrophotometer (UV-2450 Shimadzu, Japan). The lag phase was calculated by fitting the growth curve plot of concentration of cells versus –time with the Baranyi model ( Baranyi and Roberts, 1994 ) using the curve-fitting DMFit program ( Metris et al, 2006 ; Salgaonkar et al, 2016 ). The generation time ( g ) and the specific growth rate constant ( k ) was calculated from the growth curve as described by Robinson et al (2005) .…”

Section: Methodsmentioning

confidence: 99%

Antimicrobial Activity and Mechanism of Inhibition of Silver Nanoparticles against Extreme Halophilic Archaea

Thombre¹,

Shinde²,

Thaiparambil³

et al. 2016

Front. Microbiol.

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Haloarchaea are salt-loving halophilic microorganisms that inhabit marine environments, sea water, salterns, and lakes. The resistance of haloarchaea to physical extremities that challenge organismic survival is ubiquitous. Metal and antibiotic resistance of haloarchaea has been on an upsurge due to the exposure of these organisms to metal sinks and drug resistance genes augmented in their natural habitats due to anthropogenic activities and environmental pollution. The efficacy of silver nanoparticles (SNPs) as a potent and broad spectrum inhibitory agent is known, however, there are no reports on the inhibitory activity of SNPs against haloarchaea. In the present study, we have investigated the antimicrobial potentials of SNPs synthesized using aqueous leaf extract of Cinnamomum tamala against antibiotic resistant haloarchaeal isolates Haloferax prahovense RR8, Haloferax lucentense RR15, Haloarcula argentinensis RR10 and Haloarcula tradensis RR13. The synthesized SNPs were characterized by UV-Vis spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, dynamic light scattering, X-ray diffraction and Fourier transform infrared spectroscopy. The SNPs demonstrated potent antimicrobial activity against the haloarchaea with a minimum inhibitory concentration of 300–400 μg/ml. Growth kinetics of haloarchaea in the presence of SNPs was studied by employing the Baranyi mathematical model for microbial growth using the DMFit curve fitting program. The C. tamala SNPs also demonstrated cytotoxic activity against human lung adenocarcinoma epithelial cell line (A540) and human breast adenocarcinoma cell line (MCF-7). The mechanism of inhibition of haloarchaea by the SNPs was investigated. The plausible mechanism proposed is the alterations and disruption of haloarchaeal membrane permeability by turbulence, inhibition of respiratory dehydrogenases and lipid peroxidation causing cellular and DNA damage resulting in cell death.

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“…The accumulation of intracellular ions in response to stress was studied using EDAX analysis 32 . Hal.…”

Section: Methodsmentioning

confidence: 99%

Biology and survival of extremely halophilic archaeon Haloarcula marismortui RR12 isolated from Mumbai salterns, India in response to salinity stress

Thombre¹,

Shinde²,

Oke³

et al. 2016

Sci Rep

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Haloarchaea are unique microorganism’s resistant to environmental and osmotic stresses and thrive in their habitats despite extreme fluctuating salinities. In the present study, haloarchaea were isolated from hypersaline thalossohaline salterns of Bhandup, Mumbai, India and were identified as Haloferax prahovense, Haloferax alexandrines, Haloferax lucentense, Haloarcula tradensis, Haloarcula marismortui and Haloarcula argentinensis. The mechanism of adaptation to contrasting salinities (1.5 M and 4.5 M) was investigated in the extreme haloarchaeon, Hal. marismortui RR12. Hal. marismortui RR12 increased the intracellular sequestration of K+ and Cl− ions in hypo salinity and hyper salinity respectively as detected by Energy-dispersive X-ray spectroscopy microanalysis (EDAX) and Inductively Coupled Plasma- atomic Emission Spectroscopy (ICP-AES) indicating the presence of ‘salt-in’ strategy of osmoadaptation. As a cellular response to salinity stress, it produced small heat shock like proteins (sHSP) identified using MALDI-TOF MS and increased the production of protective red carotenoid pigment. This is the first report on the study of the concomitant cellular, molecular and physiological mechanism adapted by Hal. marismortui RR12 when exposed to contrasting salinities in external environment.

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Resistance of extremely halophilic archaea to zinc and zinc oxide nanoparticles

Cited by 15 publications

References 39 publications

Heavy Metal Ion Stress on Halobacterium salinarum R1 Planktonic Cells and Biofilms

Heavy Metal Ion Stress on Halobacterium salinarum R1 Planktonic Cells and Biofilms

Antimicrobial Activity and Mechanism of Inhibition of Silver Nanoparticles against Extreme Halophilic Archaea

Biology and survival of extremely halophilic archaeon Haloarcula marismortui RR12 isolated from Mumbai salterns, India in response to salinity stress

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