scholarly journals EpABC Genes in the Adaptive Responses of Exophiala pisciphila to Metal Stress: Functional Importance and Relation to Metal Tolerance

2019 ◽  
Vol 85 (23) ◽  
Author(s):  
Guan-Hua Cao ◽  
Sen He ◽  
Di Chen ◽  
Tao Li ◽  
Zhi-Wei Zhao
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Abc Transporters ◽  
Molecular Mechanisms ◽  
Metal Tolerance ◽  
Metal Resistance ◽  
Metal Species ◽  
Cd Uptake ◽  
Content Type ◽  
Exophiala Pisciphila

ABSTRACT Exophiala pisciphila is one of the dominant dark septate endophytes (DSEs) colonizing metal-polluted slag heaps in southwest China. It shows numerous super-metal-tolerant characteristics, but the molecular mechanisms involved remain largely unknown. In the present study, the functional roles of a specific set of ATP-binding cassette (ABC) transporters in E. pisciphila were characterized. In total, 26 EpABC genes belonging to 6 subfamilies (ABCA to ABCG) were annotated in previous transcriptome sequencing libraries, and all were regulated by metal ions (Pb, Zn, and Cd), which was dependent on the metal species and/or concentrations tested. The results from the heterologous expression of 3 representative EpABC genes confirmed that the expression of EpABC2.1, EpABC3.1, or EpABC4.1 restored the growth of metal-sensitive mutant Saccharomyces cerevisiae strains and significantly improved the tolerance of Arabidopsis thaliana to Pb, Zn, and Cd. Interestingly, the expression of the 3 EpABC genes further altered metal (Pb, Zn, and Cd) uptake and accumulation and promoted growth by alleviating the inhibitory activity in yeast and thale cress caused by toxic ions. These functions along with their vacuolar location suggest that the 3 EpABC transporters may enhance the detoxification of vacuolar compartmentation via transport activities across their membranes. In conclusion, the 26 annotated EpABC transporters may play a major role in maintaining the homeostasis of various metal ions in different cellular compartments, conferring an extreme adaptative advantage to E. pisciphila in metal-polluted slag heaps. IMPORTANCE Many ABC transporters and their functions have been identified in animals and plants. However, little is known about ABC genes in filamentous fungi, especially DSEs, which tend to dominantly colonize the roots of plants growing in stressed environments. Our results deepen the understanding of the function of the ABC genes of a super-metal-tolerant DSE (E. pisciphila) in enhancing its heavy metal resistance and detoxification. Furthermore, the genetic resources of DSEs, e.g., numerous EpABC genes, especially from super-metal-tolerant strains in heavy metal-polluted environments, can be directly used for transgenic applications to improve tolerance and phytoextraction potential.

scholarly journals Multiple Megaplasmids Confer Extremely High Levels of Metal Tolerance in Alteromonas Strains

2019 ◽  
Vol 86 (3) ◽  
Author(s):  
Kathleen D. Cusick ◽  
Shawn W. Polson ◽  
Gabriel Duran ◽  
Russell T. Hill
Keyword(s):  
Gene Transfer ◽  
Pseudomonas Syringae ◽  
Molecular Mechanisms ◽  
Metal Tolerance ◽  
Bioinformatic Analysis ◽  
Metal Resistance ◽  
Copper Resistance ◽  
The Other ◽  
Copper Tolerance ◽  
Content Type

ABSTRACT Alteromonas is a widely distributed genus of marine Gammaproteobacteria, with representatives shown to be key players in diverse processes, including biogeochemical cycling and biofouling of marine substrata. While Alteromonas spp. are early colonizers of copper-based antifouling paints on marine vessels, their mechanism of tolerance is poorly understood. PacBio whole-genome sequencing of Alteromonas macleodii strains CUKW and KCC02, isolated from Cu/Ni alloy test coupons submerged in oligotrophic coastal waters, indicated the presence of multiple megaplasmids (ca. 200 kb) in both. A pulsed-field gel electrophoresis method was developed and used to confirm the presence of multiple megaplasmids in these two strains; it was then used to screen additional Alteromonas strains for which little to no sequencing data exist. Plasmids were not detected in any of the other strains. Bioinformatic analysis of the CUKW and KCC02 plasmids identified numerous genes associated with metal resistance. Copper resistance orthologs from both the Escherichia coli Cue and Cus and Pseudomonas syringae Cop systems were present, at times as multiple copies. Metal growth assays in the presence of copper, cobalt, manganese, and zinc performed with 10 Alteromonas strains demonstrated the ability of CUKW and KCC02 to grow at metal concentrations inhibitory to all the other strains tested. This study reports multiple megaplasmids in Alteromonas strains. Bioinformatic analysis of the CUKW and KCC02 plasmids indicate that they harbor elements of the Tra system conjugation apparatus, although their type of mobility remains to be experimentally verified. IMPORTANCE Copper is commonly used as an antifouling agent on ship hulls. Alteromonas spp. are early colonizers of copper-based antifouling paint, but their mechanism of tolerance is poorly understood. Sequencing of A. macleodii strains isolated from copper test materials for marine ships indicated the presence of multiple megaplasmids. Plasmids serve as key vectors in horizontal gene transfer and confer traits such as metal resistance, detoxification, ecological interaction, and antibiotic resistance. Bioinformatic analysis identified many metal resistance genes and genes associated with mobility. Understanding the molecular mechanisms and capacity for gene transfer within marine biofilms provides a platform for the development of novel antifouling solutions targeting genes involved in copper tolerance and biofilm formation.

scholarly journals Mechanisms of Metal Resistance and Homeostasis in Haloarchaea

Archaea ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-16 ◽  
Author(s):  
Pallavee Srivastava ◽  
Meenal Kowshik
Keyword(s):  
Molecular Mechanisms ◽  
High Salinity ◽  
Metal Tolerance ◽  
Metal Speciation ◽  
Soda Lakes ◽  
Resistance Mechanisms ◽  
Metal Resistance ◽  
Metal Species ◽  
Physiological Processes ◽  
High Concentrations

Haloarchaea are the predominant microflora of hypersaline econiches such as solar salterns, soda lakes, and estuaries where the salinity ranges from 35 to 400 ppt. Econiches like estuaries and solar crystallizer ponds may contain high concentrations of metals since they serve as ecological sinks for metal pollution and also as effective traps for river borne metals. The availability of metals in these econiches is determined by the type of metal complexes formed and the solubility of the metal species at such high salinity. Haloarchaea have developed specialized mechanisms for the uptake of metals required for various key physiological processes and are not readily available at high salinity, beside evolving resistance mechanisms for metals with high solubility. The present paper seeks to give an overview of the main molecular mechanisms involved in metal tolerance in haloarchaea and focuses on factors such as salinity and metal speciation that affect the bioavailability of metals to haloarchaea. Global transcriptomic analysis during metal stress in these organisms will help in determining the various factors differentially regulated and essential for metal physiology.

scholarly journals Heavy Metal Tolerance Trend in Extended-Spectrum β-Lactamase Encoding Strains Recovered from Food Samples

2021 ◽  
Vol 18 (9) ◽  
pp. 4718
Author(s):  
Kashaf Junaid ◽  
Hasan Ejaz ◽  
Iram Asim ◽  
Sonia Younas ◽  
Humaira Yasmeen ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Metal Tolerance ◽  
Heavy Metal Tolerance ◽  
Heavy Metal Resistance ◽  
Metal Resistance ◽  
Food Samples ◽  
Esbl Production ◽  
Extended Spectrum ◽  
Retail Food ◽  
Esbl Producers

This study evaluates bacteriological profiles in ready-to-eat (RTE) foods and assesses antibiotic resistance, extended-spectrum β-lactamase (ESBL) production by gram-negative bacteria, and heavy metal tolerance. In total, 436 retail food samples were collected and cultured. The isolates were screened for ESBL production and molecular detection of ESBL-encoding genes. Furthermore, all isolates were evaluated for heavy metal tolerance. From 352 culture-positive samples, 406 g-negative bacteria were identified. Raw food samples were more often contaminated than refined food (84.71% vs. 76.32%). The predominant isolates were Klebsiella pneumoniae (n = 76), Enterobacter cloacae (n = 58), and Escherichia coli (n = 56). Overall, the percentage of ESBL producers was higher in raw food samples, although higher occurrences of ESBL-producing E. coli (p = 0.01) and Pseudomonas aeruginosa (p = 0.02) were observed in processed food samples. However, the prevalence of ESBL-producing Citrobacter freundii in raw food samples was high (p = 0.03). Among the isolates, 55% were blaCTX-M, 26% were blaSHV, and 19% were blaTEM. Notably, heavy metal resistance was highly prevalent in ESBL producers. These findings demonstrate that retail food samples are exposed to contaminants including antibiotics and heavy metals, endangering consumers.

Molecular Mechanisms of Heavy Metal Tolerance in Plants

2020 ◽  
pp. 125-136
Author(s):  
Nasser Delangiz ◽  
Bahman Khoshru ◽  
Behnam Asgari Lajayer ◽  
Mansour Ghorbanpour ◽  
Solmaz Kazemalilou
Keyword(s):  
Heavy Metal ◽  
Molecular Mechanisms ◽  
Metal Tolerance ◽  
Heavy Metal Tolerance

scholarly journals Draft Genome Sequence of Heavy Metal-Resistant Bacillus cereus NWUAB01

2019 ◽  
Vol 8 (7) ◽  
Author(s):  
Olubukola Oluranti Babalola ◽  
Bukola Rhoda Aremu ◽  
Ayansina Segun Ayangbenro
Keyword(s):  
Heavy Metal ◽  
Bacillus Cereus ◽  
Genome Sequence ◽  
Gold Mining ◽  
Draft Genome ◽  
Heavy Metal Resistance ◽  
Metal Resistance ◽  
Draft Genome Sequence ◽  
Mining Site ◽  
Content Type

Bacillus cereus NWUAB01 was isolated from a gold-mining site in Vryburg, South Africa, for its multiple heavy metal resistance properties. Here, we report the draft genome sequence of B. cereus NWUAB01 obtained with Illumina sequencing.

scholarly journals Multiple Transporters and Glycoside Hydrolases Are Involved in Arabinoxylan-Derived Oligosaccharide Utilization in Bifidobacterium pseudocatenulatum

2020 ◽  
Vol 86 (24) ◽  
Author(s):  
Yuki Saito ◽  
Akira Shigehisa ◽  
Yohei Watanabe ◽  
Naoki Tsukuda ◽  
Kaoru Moriyama-Ohara ◽  
...  
Keyword(s):  
Abc Transporters ◽  
Binding Proteins ◽  
Molecular Mechanisms ◽  
Bifidobacterium Longum ◽  
Gene Clusters ◽  
Glycoside Hydrolases ◽  
Glycoside Hydrolase Family ◽  
Carbohydrate Utilization ◽  
Bifidobacterium Adolescentis ◽  
Content Type

ABSTRACT Arabinoxylan hydrolysates (AXH) are the hydrolyzed products of the major components of the dietary fiber arabinoxylan. AXH include diverse oligosaccharides varying in xylose polymerization and side residue modifications with arabinose at the O-2 and/or O-3 position of the xylose unit. Previous studies have reported that AXH exhibit prebiotic properties on gut bifidobacteria; moreover, several adult-associated bifidobacterial species (e.g., Bifidobacterium adolescentis and Bifidobacterium longum subsp. longum) are known to utilize AXH. In this study, we tried to elucidate the molecular mechanisms of AXH utilization by Bifidobacterium pseudocatenulatum, which is a common bifidobacterial species found in adult feces. We performed transcriptomic analysis of B. pseudocatenulatum YIT 4072T, which identified three upregulated gene clusters during AXH utilization. The gene clusters encoded three sets of ATP-binding cassette (ABC) transporters and five enzymes belonging to glycoside hydrolase family 43 (GH43). By characterizing the recombinant proteins, we found that three solute-binding proteins of ABC transporters showed either broad or narrow specificity, two arabinofuranosidases hydrolyzed either single- or double-decorated arabinoxylooligosaccharides, and three xylosidases exhibited functionally identical activity. These data collectively suggest that the transporters and glycoside hydrolases, encoded in the three gene clusters, work together to utilize AXH of different sizes and with different side residue modifications. Thus, our study sheds light on the overall picture of how these proteins collaborate for the utilization of AXH in B. pseudocatenulatum and may explain the predominance of this symbiont species in the adult human gut. IMPORTANCE Bifidobacteria commonly reside in the human intestine and possess abundant genes involved in carbohydrate utilization. Arabinoxylan hydrolysates (AXH) are hydrolyzed products of arabinoxylan, one of the most abundant dietary fibers, and they include xylooligosaccharides and those decorated with arabinofuranosyl residues. The molecular mechanism by which B. pseudocatenulatum, a common bifidobacterial species found in adult feces, utilizes structurally and compositionally variable AXH has yet to be extensively investigated. In this study, we identified three gene clusters (encoding five GH43 enzymes and three solute-binding proteins of ABC transporters) that were upregulated in B. pseudocatenulatum YIT 4072T during AXH utilization. By investigating their substrate specificities, we revealed how these proteins are involved in the uptake and degradation of AXH. These molecular insights may provide a better understanding of how resident bifidobacteria colonize the colon.

Molecular mechanisms of heavy metal tolerance and evolution in invertebrates

2009 ◽  
Vol 16 (1) ◽  
pp. 3-18 ◽  
Author(s):  
Thierry K. S. Janssens ◽  
Dick Roelofs ◽  
Nico M. van Straalen
Keyword(s):  
Heavy Metal ◽  
Molecular Mechanisms ◽  
Metal Tolerance ◽  
Heavy Metal Tolerance

scholarly journals Draft Genome Sequence of the Phosphate-Solubilizing Rhizobacterium Burkholderia pseudomultivorans Strain MPSB1, Isolated from a Copper Mined-Out Site

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Berna Lou L. Aba-Regis ◽  
Kristel Mae P. Oliveros ◽  
Cherry Ibarra-Romero ◽  
Asuncion K. Raymundo ◽  
Nelly S. Aggangan ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Soil Sample ◽  
Genome Sequence ◽  
Phosphate Solubilization ◽  
Metal Tolerance ◽  
Draft Genome ◽  
Heavy Metal Tolerance ◽  
Draft Genome Sequence ◽  
Content Type ◽  
Phosphate Solubilizing

ABSTRACT Burkholderia pseudomultivorans MPSB1 was isolated from a copper mined-out soil sample collected from Mogpog, Marinduque, Philippines. Here, we report the draft genome sequence with predicted gene inventories supporting rhizosphere bioremediation, such as heavy metal tolerance, phosphate solubilization, and siderophore production.

scholarly journals Draft Genome Sequence of Arthrobacter oryzae TNBS02, a Bacterium Containing Heavy Metal Resistance Genes, Isolated from Soil of Antarctica

2019 ◽  
Vol 8 (4) ◽  
Author(s):  
Yong-Joon Cho ◽  
Ahnna Cho ◽  
Soon Gyu Hong ◽  
Han-Gu Choi ◽  
Ok-Sun Kim
Keyword(s):  
Heavy Metal ◽  
Genome Sequence ◽  
Resistance Genes ◽  
Draft Genome ◽  
Heavy Metal Resistance ◽  
Metal Resistance ◽  
Draft Genome Sequence ◽  
Content Type ◽  
Terra Nova Bay ◽  
Victoria Land

Arthrobacter oryzae TNBS02 was isolated from soil at Terra Nova Bay of Victoria Land, Antarctica. The genome consists of a chromosome with 4,248,670 bp which contains a total of 3,994 genes.

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