scholarly journals Development of a bioavailable Hg(II) sensing system based on MerR-regulated visual pigment biosynthesis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yan Guo ◽  
Chang-ye Hui ◽  
Lisa Liu ◽  
Min-peng Chen ◽  
Hong-ying Huang
Keyword(s):  
Linear Relationship ◽  
Colorimetric Method ◽  
Green Fluorescence Protein ◽  
Heavy Metal Resistance ◽  
Environmental Water ◽  
Response Strength ◽  
Metal Resistance ◽  
Mercury Resistance ◽  
Specific Response ◽  
Time Required

AbstractEngineered microorganisms have proven to be a highly effective and robust tool to specifically detect heavy metals in the environment. In this study, a highly specific pigment-based whole-cell biosensor has been investigated for the detection of bioavailable Hg(II) based on an artificial heavy metal resistance operon. The basic working principle of biosensors is based on the violacein biosynthesis under the control of mercury resistance (mer) promoter and mercury resistance regulator (MerR). Engineered biosensor cells have been demonstrated to selectively respond to Hg(II), and the specific response was not influenced by interfering metal ions. The response of violacein could be recognized by the naked eye, and the time required for the maximum response of violacein (5 h) was less than that of enhanced green fluorescence protein (eGFP) (8 h) in the single-signal output constructs. The response of violacein was almost unaffected by the eGFP in a double-promoter controlled dual-signals output construct. However, the response strength of eGFP was significantly decreased in this genetic construct. Exponentially growing violacein-based biosensor detected concentrations as low as 0.39 μM Hg(II) in a colorimetric method, and the linear relationship was observed in the concentration range of 0.78–12.5 μM. Non-growing biosensor cells responded to concentrations as low as 0.006 μM Hg(II) in a colorimetric method and in a Hg(II) containing plate sensitive assay, and the linear relationship was demonstrated in a very narrow concentration range. The developed biosensor was finally validated for the detection of spiked bioavailable Hg(II) in environmental water samples.

scholarly journals 556. Phylogenomic Epidemiology of Methicillin-Resistant Staphylococcus aureus (MRSA) Chilean-Cordobes Clone in Latin America

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S263-S264
Author(s):  
Jose R W Martínez ◽  
Lorena Diaz ◽  
Marcelo Rojas ◽  
Rafael Rios ◽  
Blake Hanson ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Latin America ◽  
Molecular Clock ◽  
Bloodstream Infections ◽  
Heavy Metal Resistance ◽  
Metal Resistance ◽  
Mercury Resistance ◽  
Clock Analysis ◽  
Time Of Divergence ◽  
The City

Abstract Background The MRSA Chilean-Cordobes (ChC) clone belongs to the clonal complex 5 (CC5) and typically carries SCCmec I. The ChC clone predominated widely throughout several countries of Latin America (LA), but during the mid-2000s a CA-MRSA CC8 LA variant (USA300-LV) quickly replaced the ChC in Colombia and Ecuador. Most notably, this replacement was not observed in Peru or Chile. Here, we aimed to understand the phylogenomic relatedness of the CC5 ChC clone obtained from different countries of LA. Methods We sequenced and analyzed the genomes of 115 MRSA isolates obtained between 2011–2014 from bloodstream infections in 6 LA countries (Argentina, Brazil, Colombia, Chile, Peru, and Venezuela). All isolates were confirmed as ChC clone by pulsed-field gel electrophoresis (PFGE). We used core genome-based phylogenomic reconstructions and molecular clock analysis to infer the relationships and time of divergence between clades. Results Whole-genome-based multilocus sequence typing determined that 110/115 isolates belonged to ST5 and carried SCCmec I. The phylogenomic reconstruction showed ChC isolates clustered into 4 major clades distinctly segregated by country of origin (Figure 1). Interestingly, isolates recovered from Chile divided into 2 different clades that segregate according to the city of origin (Santiago [SCL] or Concepción [CON]), suggesting these clades evolved independently. Molecular clock analyses suggested all clades share a common ancestor with the divergence of the Chilean clades occurring earlier (Figure 2). Of note, analysis of heavy metal genes suggested the divergence between Chilean isolates was characterized by the loss of a mercury resistance gene cluster, which is present in an 88% of CON isolates, but only in 28% of SCL (Figure 2). Conclusion MRSA isolates belonging to the ChC clone from 6 LA countries clustered in 4 clades according to the geographical region of isolation. This segregation suggests divergent adaptations that may respond to different selective pressures. Heavy metal resistance could play a role in the ability of the MRSA ChC to disseminate in specific geographical locations. Disclosures All authors: No reported disclosures.

scholarly journals Plasmids pMOL28 and pMOL30 of Cupriavidus metallidurans Are Specialized in the Maximal Viable Response to Heavy Metals

2007 ◽  
Vol 189 (20) ◽  
pp. 7417-7425 ◽  
Author(s):  
Sébastien Monchy ◽  
Mohammed A. Benotmane ◽  
Paul Janssen ◽  
Tatiana Vallaeys ◽  
Safiyh Taghavi ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Heavy Metal Stress ◽  
Heavy Metal Resistance ◽  
Metal Resistance ◽  
Genomic Islands ◽  
Specific Response ◽  
Resistance Proteins ◽  
Cupriavidus Metallidurans ◽  
General Response

ABSTRACT We fully annotated two large plasmids, pMOL28 (164 open reading frames [ORFs]; 171,459 bp) and pMOL30 (247 ORFs; 233,720 bp), in the genome of Cupriavidus metallidurans CH34. pMOL28 contains a backbone of maintenance and transfer genes resembling those found in plasmid pSym of C. taiwanensis and plasmid pHG1 of C. eutrophus, suggesting that they belong to a new class of plasmids. Genes involved in resistance to the heavy metals Co(II), Cr(VI), Hg(II), and Ni(II) are concentrated in a 34-kb region on pMOL28, and genes involved in resistance to Ag(I), Cd(II), Co(II), Cu(II), Hg(II), Pb(II), and Zn(II) occur in a 132-kb region on pMOL30. We identified three putative genomic islands containing metal resistance operons flanked by mobile genetic elements, one on pMOL28 and two on pMOL30. Transcriptomic analysis using quantitative PCR and microarrays revealed metal-mediated up-regulation of 83 genes on pMOL28 and 143 genes on pMOL30 that coded for all known heavy metal resistance proteins, some new heavy metal resistance proteins (czcJ, mmrQ, and pbrU), membrane proteins, truncated transposases, conjugative transfer proteins, and many unknown proteins. Five genes on each plasmid were down-regulated; for one of them, chrI localized on pMOL28, the down-regulation occurred in the presence of five cations. We observed multiple cross-responses (induction of specific metal resistance by other metals), suggesting that the cellular defense of C. metallidurans against heavy metal stress involves various regulons and probably has multiple stages, including a more general response and a more metal-specific response.

scholarly journals Comparative Genomic Analysis of 450 Strains of Salmonella enterica Isolated from Diseased Animals

Genes ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 1025
Author(s):  
Shaohua Zhao ◽  
Cong Li ◽  
Chih-Hao Hsu ◽  
Gregory H. Tyson ◽  
Errol Strain ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Bacterial Infections ◽  
Genomic Analysis ◽  
Heavy Metal Resistance ◽  
Metal Resistance ◽  
Comparative Genomic ◽  
Salmonella Infections ◽  
Antimicrobial Resistance Genes ◽  
Salmonella Pathogenicity Islands ◽  
Shed Light

Salmonella is a leading cause of bacterial infections in animals and humans. We sequenced a collection of 450 Salmonella strains from diseased animals to better understand the genetic makeup of their virulence and resistance features. The presence of Salmonella pathogenicity islands (SPIs) varied by serotype. S. Enteritidis carried the most SPIs (n = 15), while S. Mbandaka, S. Cerro, S. Meleagridis, and S. Havana carried the least (n = 10). S. Typhimurium, S. Choleraesuis, S. I 4,5,12:i:-, and S. Enteritidis each contained the spv operon on IncFII or IncFII-IncFIB hybrid plasmids. Two S. IIIa carried a spv operon with spvD deletion on the chromosome. Twelve plasmid types including 24 hybrid plasmids were identified. IncA/C was frequently associated with S. Newport (83%) and S. Agona (100%) from bovine, whereas IncFII (100%), IncFIB (100%), and IncQ1 (94%) were seen in S. Choleraesuis from swine. IncX (100%) was detected in all S. Kentucky from chicken. A total of 60 antimicrobial resistance genes (ARGs), four disinfectant resistances genes (DRGs) and 33 heavy metal resistance genes (HMRGs) were identified. The Salmonella strains from sick animals contained various SPIs, resistance genes and plasmid types based on the serotype and source of the isolates. Such complicated genomic structures shed light on the strain characteristics contributing to the severity of disease and treatment failures in Salmonella infections, including those causing illnesses in animals.

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.

scholarly journals Genome-Driven Discovery of Enzymes with Industrial Implications from the Genus Aneurinibacillus

2021 ◽  
Vol 9 (3) ◽  
pp. 499
Author(s):  
Majid Rasool Kamli ◽  
Nada A. Y. Alzahrani ◽  
Nahid H. Hajrah ◽  
Jamal S. M. Sabir ◽  
Adeel Malik
Keyword(s):  
Heavy Metal ◽  
Enzyme Activities ◽  
Heavy Metal Resistance ◽  
Industrial Applications ◽  
Metal Resistance ◽  
The Family ◽  
Antiviral Activities ◽  
Genome Level ◽  
Genome Analyses ◽  
Unique Species

Bacteria belonging to the genus Aneurinibacillus within the family Paenibacillaceae are Gram-positive, endospore-forming, and rod-shaped bacteria inhabiting diverse environments. Currently, there are eight validly described species of Aneurinibacillus; however, several unclassified species have also been reported. Aneurinibacillus spp. have shown the potential for producing secondary metabolites (SMs) and demonstrated diverse types of enzyme activities. These features make them promising candidates with industrial implications. At present, genomes of 9 unique species from the genus Aneurinibacillus are available, which can be utilized to decipher invaluable information on their biosynthetic potential as well as enzyme activities. In this work, we performed the comparative genome analyses of nine Aneurinibacillus species representing the first such comprehensive study of this genus at the genome level. We focused on discovering the biosynthetic, biodegradation, and heavy metal resistance potential of this under-investigated genus. The results indicate that the genomes of Aneurinibacillus contain SM-producing regions with diverse bioactivities, including antimicrobial and antiviral activities. Several carbohydrate-active enzymes (CAZymes) and genes involved in heavy metal resistance were also identified. Additionally, a broad range of enzyme classes were also identified in the Aneurinibacillus pan-genomes, making this group of bacteria potential candidates for future investigations with industrial applications.

scholarly journals Retromobilization of heavy metal resistance genes in unpolluted and heavy metal polluted soil

1995 ◽  
Vol 18 (3) ◽  
pp. 191-203 ◽  
Author(s):  
Eva M. Top ◽  
Helene Rore ◽  
Jean-Marc Collard ◽  
Veerle Gellens ◽  
Galina Slobodkina ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Resistance Genes ◽  
Heavy Metal Resistance ◽  
Metal Resistance ◽  
Polluted Soil

scholarly journals Replication of Staphylococcal Multiresistance Plasmids

2000 ◽  
Vol 182 (8) ◽  
pp. 2170-2178 ◽  
Author(s):  
Neville Firth ◽  
Sumalee Apisiridej ◽  
Tracey Berg ◽  
Brendon A. O'Rourke ◽  
Steve Curnock ◽  
...  
Keyword(s):  
Sequence Similarity ◽  
Heavy Metal Resistance ◽  
Metal Resistance ◽  
Replication Initiation ◽  
Conjugative Plasmid ◽  
Rolling Circle ◽  
Segregational Stability ◽  
Structural And Functional Properties ◽  
Resistance Plasmids ◽  
Genes Encoding

ABSTRACT Based on structural and functional properties, three groups of large staphylococcal multiresistance plasmids have been recognized, viz., the pSK1 family, pSK41-like conjugative plasmids, and β-lactamase–heavy-metal resistance plasmids. Here we describe an analysis of the replication functions of a representative of each of these plasmid groups. The replication initiation genes from theStaphylococcus aureus plasmids pSK1, pSK41, and pI9789::Tn552 were found to be related to each other and to the Staphylococcus xylosus plasmid pSX267 and are also related to rep genes of several plasmids from other gram-positive genera. Nucleotide sequence similarity between pSK1 and pI9789::Tn552 extended beyond theirrep genes, encompassing upstream divergently transcribed genes, orf245 and orf256, respectively. Our analyses revealed that genes encoding proteins related to the deducedorf245 product are variously represented, in several types of organization, on plasmids possessing six seemingly evolutionarily distinct types of replication initiation genes and including both theta-mode and rolling-circle replicons. Construction of minireplicons and subsequent functional analysis demonstrated that orf245is required for the segregational stability of the pSK1 replicon. In contrast, no gene equivalent to orf245 is evident on the conjugative plasmid pSK41, and a minireplicon encoding only the pSK41 rep gene was found to exhibit a segregational stability approaching that of the parent plasmid. Significantly, the results described establish that many of the large multiresistance plasmids that have been identified in clinical staphylococci, which were formerly presumed to be unrelated, actually utilize an evolutionarily related theta-mode replication system.

Screening of heavy metal and antibiotic resistance among Proteus vulgaris isolates from hospital wastewater of Northern India

2021 ◽  
Vol 19 ◽  
Author(s):  
Manzar Alam ◽  
Mohd Imran ◽  
Syed Sayeed Ahmad
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Multiple Drug Resistance ◽  
Heavy Metal Resistance ◽  
Metal Resistance ◽  
Antibiotics Resistance ◽  
Proteus Vulgaris ◽  
Resistance To Antibiotics ◽  
Transfer Frequency ◽  
Resistance Patterns

Background: Microbial resistance to antibiotics and heavy metals is a rising problem in the world today. All the Proteus vulgaris isolates showed their MIC in between 50-1600 µg/ml. Of 70% and 46% of the isolates showed their MIC at 800-1200 µg/ml against Zn2+ and Cu2+ while 80% of the isolates showed their MIC at 100-200 µg/ml against Ni2+, respectively. All Proteus vulgaris isolates also exhibited multiple resistance patterns (2-7 heavy metals) in different combination of metals. The Multi metal resistance Index (MHMR) ranges were found (0.04-0.5). Methods: A high level of antibiotics resistance was observed against Methicillin (100%) and least to Oflaxicin (6%), Gentamycine and Neomycin (10%). All Proteus vulgaris isolates also showed multiple drug resistance patterns (2-12 antibiotics) in different combination of antibiotics. The MAR index ranges were found (0.02-0.7). Of 98%, 84% and 80% of the total isolates showed urease, gelatinase and amylase activity. Results: The Proteus vulgaris isolates contained plasmid of size ranging from 42.5 to 57.0kb and molecular weight of plasmids ranged from 27.2 to 37.0 MD. Incidences of resistance transfer, 7 pairs of isolates were assessed for the transfer of the antibiotic/ heavy metal resistance markers. The higher (4.4x10-1 and 3.4x10-1) transfer frequency was observed among antibiotic and heavy metal while lower transfer frequency were (5.0x10-2 and 1.0x10-2) showed against antibiotic and heavy metal in both the medium from the entire site tested, respectively. Conclusion: Indicating the high threat of environmental pollution and appearance of heavy metal resistance which may support the enlargement of resistance to antibiotics among the pathogens.

scholarly journals Target (MexB)- and Efflux-Based Mechanisms Decreasing the Effectiveness of the Efflux Pump Inhibitor D13-9001 in Pseudomonas aeruginosa PAO1: Uncovering a New Role for MexMN-OprM in Efflux of β-Lactams and a Novel Regulatory Circuit (MmnRS) Controlling MexMN Expression

2018 ◽  
Vol 63 (2) ◽  
pp. e01718-18 ◽  
Author(s):  
Srijan Ranjitkar ◽  
Adriana K. Jones ◽  
Mina Mostafavi ◽  
Zachary Zwirko ◽  
Oleg Iartchouk ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Efflux Pump ◽  
Response Regulator ◽  
Heavy Metal Resistance ◽  
Metal Resistance ◽  
Rna Seq ◽  
Efflux Pump Inhibitor ◽  
Content Type ◽  
Regulatory Circuit ◽  
Outer Membrane Channel

ABSTRACT Efflux pumps contribute to antibiotic resistance in Gram-negative pathogens. Correspondingly, efflux pump inhibitors (EPIs) may reverse this resistance. D13-9001 specifically inhibits MexAB-OprM in Pseudomonas aeruginosa. Mutants with decreased susceptibility to MexAB-OprM inhibition by D13-9001 were identified, and these fell into two categories: those with alterations in the target MexB (F628L and ΔV177) and those with an alteration in a putative sensor kinase of unknown function, PA1438 (L172P). The alterations in MexB were consistent with reported structural studies of the D13-9001 interaction with MexB. The PA1438L172P alteration mediated a >150-fold upregulation of MexMN pump gene expression and a >50-fold upregulation of PA1438 and the neighboring response regulator gene, PA1437. We propose that these be renamed mmnR and mmnS for MexMN regulator and MexMN sensor, respectively. MexMN was shown to partner with the outer membrane channel protein OprM and to pump several β-lactams, monobactams, and tazobactam. Upregulated MexMN functionally replaced MexAB-OprM to efflux these compounds but was insusceptible to inhibition by D13-9001. MmnSL172P also mediated a decrease in susceptibility to imipenem and biapenem that was independent of MexMN-OprM. Expression of oprD, encoding the uptake channel for these compounds, was downregulated, suggesting that this channel is also part of the MmnSR regulon. Transcriptome sequencing (RNA-seq) of cells encoding MmnSL172P revealed, among other things, an interrelationship between the regulation of mexMN and genes involved in heavy metal resistance.

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