Spectroscopic investigation of the reaction mechanism of CopB-B, the catalytic fragment from an archaeal thermophilic ATP-driven heavy metal transporter

Populus alba ‘Villafranca’ clone is well-known for its tolerance to cadmium (Cd). To determine the mechanisms of Cd tolerance of this species, wild-type (wt) plants were compared with transgenic plants over-expressing an aquaporin (aqua1, GenBank GQ918138). Plants were maintained in hydroponic conditions with Hoagland’s solution and treated with 10 µM of Cd, renewed every 5 d. The transcription levels of heavy metal transporter genes (PaHMA2, PaNRAMP1.3, PaNRAMP2, PaNRAMP3.1, PaNRAMP3.2, PaABCC9, and PaABCC13) were analyzed at 1, 7, and 60 d of treatment. Cd application did not induce visible toxicity symptoms in wt and aqua1 plants even after 2 months of treatment confirming the high tolerance of this poplar species to Cd. Most of the analyzed genes showed in wt plants a quick response in transcription at 1 d of treatment and an adaptation at 60 d. On the contrary, a lower transcriptional response was observed in aqua1 plants in concomitance with a higher Cd concentration in medial leaves. Moreover, PaHMA2 showed at 1 d an opposite trend within organs since it was up-regulated in root and stem of wt plants and in leaves of aqua1 plants. In summary, aqua1 overexpression in poplar improved Cd translocation suggesting a lower Cd sensitivity of aqua1 plants. This different response might be due to a different transcription of PaNRAMP3 genes that were more transcribed in wt line because of the importance of this gene in Cd compartmentalization.

Download Full-text

VTC4 Polyphosphate Polymerase Knockout Increases Stress Resistance of Saccharomyces cerevisiae Cells

Biology ◽

10.3390/biology10060487 ◽

2021 ◽

Vol 10 (6) ◽

pp. 487

Author(s):

Alexander Tomashevsky ◽

Ekaterina Kulakovskaya ◽

Ludmila Trilisenko ◽

Ivan V. Kulakovskiy ◽

Tatiana Kulakovskaya ◽

...

Keyword(s):

Saccharomyces Cerevisiae ◽

Heavy Metal ◽

Stress Response ◽

Stress Resistance ◽

Alkaline Stress ◽

Inorganic Polyphosphate ◽

Divalent Metal Transporter ◽

Metal Transporter ◽

Elevated Expression ◽

Chaperone Complex

Inorganic polyphosphate (polyP) is an important factor of alkaline, heavy metal, and oxidative stress resistance in microbial cells. In yeast, polyP is synthesized by Vtc4, a subunit of the vacuole transporter chaperone complex. Here, we report reduced but reliably detectable amounts of acid-soluble and acid-insoluble polyPs in the Δvtc4 strain of Saccharomyces cerevisiae, reaching 10% and 20% of the respective levels of the wild-type strain. The Δvtc4 strain has decreased resistance to alkaline stress but, unexpectedly, increased resistance to oxidation and heavy metal excess. We suggest that increased resistance is achieved through elevated expression of DDR2, which is implicated in stress response, and reduced expression of PHO84 encoding a phosphate and divalent metal transporter. The decreased Mg2+-dependent phosphate accumulation in Δvtc4 cells is consistent with reduced expression of PHO84. We discuss a possible role that polyP level plays in cellular signaling of stress response mobilization in yeast.

Download Full-text

Mutation in OsFWL7 Affects Cadmium and Micronutrient Metal Accumulation in Rice

International Journal of Molecular Sciences ◽

10.3390/ijms222212583 ◽

2021 ◽

Vol 22 (22) ◽

pp. 12583

Author(s):

Qingsong Gao ◽

Lei Liu ◽

Haiying Zhou ◽

Xi Liu ◽

Wei Li ◽

...

Keyword(s):

Heavy Metal ◽

Molecular Mechanisms ◽

Metal Accumulation ◽

Normal Growth ◽

Growth Conditions ◽

Membrane Microdomains ◽

Metal Transporter ◽

Membrane Microdomain ◽

Marker Proteins ◽

Family Gene

Micronutrient metals, such as Mn, Cu, Fe, and Zn, are essential heavy metals for plant growth and development, while Cd is a nonessential heavy metal that is highly toxic to both plants and humans. Our understanding of the molecular mechanisms underlying Cd and micronutrient metal accumulation in plants remains incomplete. Here, we show that OsFWL7, an FW2.2-like (FWL) family gene in Oryza sativa, is preferentially expressed in the root and encodes a protein localized to the cell membrane. The osfwl7 mutation reduces both the uptake and the root-to-shoot translocation of Cd in rice plants. Additionally, the accumulation of micronutrient metals, including Mn, Cu, and Fe, was lower in osfwl7 mutants than in the wildtype plants under normal growth conditions. Moreover, the osfwl7 mutation affects the expression of several heavy metal transporter genes. Protein interaction analyses reveal that rice FWL proteins interact with themselves and one another, and with several membrane microdomain marker proteins. Our results suggest that OsFWL7 is involved in Cd and micronutrient metal accumulation in rice. Additionally, rice FWL proteins may form oligomers and some of them may be located in membrane microdomains.

Download Full-text

A multi-colorimetric probe to discriminate between heavy metal cations and anions in DMSO–H2O with high selectivity for Cu2+ and CN−: study of logic functions and its application in real samples

RSC Advances ◽

10.1039/d1ra04734e ◽

2021 ◽

Vol 11 (47) ◽

pp. 29466-29485

Author(s):

Eunike Hamukwaya ◽

Johannes Naimhwaka ◽

Veikko Uahengo

Keyword(s):

Heavy Metal ◽

Schiff Base ◽

Reaction Mechanism ◽

High Selectivity ◽

Colorimetric Probe ◽

Real Samples ◽

Heavy Metal Cations ◽

H Nmr ◽

Vis Spectroscopy ◽

Logic Functions

A ditopic multi-colorimetric probe based on the phenylpridyl-thioic moiety (EN) was synthesized via a Schiff base reaction mechanism and characterized using 1H NMR and UV-vis spectroscopy.

Download Full-text

Mechanism of Heavy Metal ATPase (HMA2, HMA3 and HMA4) Genes

Nano-Phytoremediation Technologies for Groundwater Contaminates - Advances in Environmental Engineering and Green Technologies ◽

10.4018/978-1-5225-9016-3.ch008 ◽

2020 ◽

pp. 104-117

Keyword(s):

Heavy Metals ◽

Heavy Metal ◽

Heavy Metal Ions ◽

Metal Tolerance ◽

Heavy Metal Tolerance ◽

Land Plant ◽

Signaling Mechanism ◽

Metal Transporter ◽

Metals Tolerance ◽

Environmentally Sound

Heavy metals are the most important pollutants that are non-biodegradable and increasingly accumulate in the environment. Phytoremediation can be defined as the use of plants for the extraction, immobilization, containment, or degradation of contaminants. It provides an ecologically, environmentally sound and safe method for restoration and remediation of contaminated land. Plant species vary in their capacity of hyper-accumulation of heavy metals. The chapter reviews the current findings on the molecular mechanism involved in heavy metals tolerance, which is a valuable tool for phytoremediation. The heavy metal tolerance genes help in the hyper-accumulation trait of a plant. Heavy metal transporter ATPases (HMAs) genes help in the refluxing of heavy metal ions from the cytosol, either into the apoplast, the vacuole, or other organelles, which help in the hyperaccumulation of metal. Understanding the signaling mechanism of transporter genes will be an important tool to understand the genetics of hyperaccumulation.

Download Full-text