Use of Bacteria To Stabilize Archaeological Iron

ABSTRACT Iron artifacts are common among the findings of archaeological excavations. The corrosion layer formed on these objects requires stabilization after their recovery, without which the destruction of the item due to physicochemical damage is likely. Current technologies for stabilizing the corrosion layer are lengthy and generate hazardous waste products. Therefore, there is a pressing need for an alternative method for stabilizing the corrosion layer on iron objects. The aim of this study was to evaluate an alternative conservation-restoration method using bacteria. For this, anaerobic iron reduction leading to the formation of stable iron minerals in the presence of chlorine was investigated for two strains of Desulfitobacterium hafniense (strains TCE1 and LBE). Iron reduction was observed for soluble Fe(III) phases as well as for akaganeite, the most troublesome iron compound in the corrosion layer of archaeological iron objects. In terms of biogenic mineral production, differential efficiencies were observed in assays performed on corroded iron coupons. Strain TCE1 produced a homogeneous layer of vivianite covering 80% of the corroded surface, while on the coupons treated with strain LBE, only 10% of the surface was covered by the same mineral. Finally, an attempt to reduce iron on archaeological objects was performed with strain TCE1, which led to the formation of both biogenic vivianite and magnetite on the surface of the artifacts. These results demonstrate the potential of this biological treatment for stabilizing archaeological iron as a promising alternative to traditional conservation-restoration methods. IMPORTANCE Since the Iron Age, iron has been a fundamental material for the building of objects used in everyday life. However, due to its reactivity, iron can be easily corroded, and the physical stability of the object built is at risk. This is particularly true for archaeological objects on which a potentially unstable corrosion layer is formed during the time the object is buried. After excavation, changes in environmental conditions (e.g., higher oxygen concentration or lower humidity) alter the stability of the corrosion layer and can lead to the total destruction of the object. In this study, we demonstrate the feasibility of an innovative treatment based on bacterial iron reduction and biogenic mineral formation to stabilize the corrosion layer and protect these objects.

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Critical Concentration of Lecithin Enhances the Antimicrobial Activity of Eugenol against Escherichia coli

Applied and Environmental Microbiology ◽

10.1128/aem.03467-16 ◽

2017 ◽

Vol 83 (8) ◽

Cited By ~ 6

Author(s):

Haoshu Zhang ◽

Edward G. Dudley ◽

P. Michael Davidson ◽

Federico Harte

Keyword(s):

Escherichia Coli ◽

Essential Oils ◽

Food Systems ◽

Critical Concentration ◽

Physical Stability ◽

Antimicrobial Properties ◽

Content Type ◽

Antimicrobial Effects ◽

Wide Range ◽

The Stability

ABSTRACT Lecithin is a natural emulsifier used in a wide range of food and nonfood applications to improve physical stability, with no known bioactive effects. In this study, the effect of lecithin on the antimicrobial performance of a constant eugenol concentration was tested against three Escherichia coli strains (C600, 0.1229, and O157:H7 strain ATCC 700728). This is the first study, to our knowledge, focusing on lecithin at concentrations below those commonly used in foods to improve the stability of oil in water emulsions (≤10 mg/100 ml). For all three cultures, significant synergistic antimicrobial effects were observed when E. coli cultures were exposed to a constant eugenol concentration (ranging from 0.043 to 0.050% [wt/wt]) together with critical lecithin concentrations ranging from 0.5 to 1 mg/100 ml. Increasing the concentration of lecithin above 1 mg/100 ml (up to 10 mg/100 ml lecithin) diminished the antibacterial effect to values similar to those with eugenol-only treatments. The formation of aggregates (<100 nm) at the critical lecithin concentration was observed using cryo-transmission electron microscopy (cryo-TEM), together with a reduction in light absorbance at 284 nm. At critically low concentrations of lecithin, the formation of nanoscale aggregates is responsible for improving eugenol antimicrobial effects. IMPORTANCE Essential oils (EOs) are effective natural antimicrobials. However, their hydrophobicity and strong aromatic character limit the use of essential oils in food systems. Emulsifiers (e.g., lecithin) increase the stability of EOs in water-based systems but fail to consistently improve antimicrobial effects. We demonstrate that lecithin, within a narrow critical concentration window, can enhance the antimicrobial properties of eugenol. This study highlights the potential bioactivity of lecithin when utilized to effectively control foodborne pathogens.

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The Radiostability of Meropenem Trihydrate in Solid State

Molecules ◽

10.3390/molecules23112738 ◽

2018 ◽

Vol 23 (11) ◽

pp. 2738 ◽

Cited By ~ 2

Author(s):

Karolina Kilińska ◽

Judyta Cielecka-Piontek ◽

Robert Skibiński ◽

Daria Szymanowska ◽

Andrzej Miklaszewski ◽

...

Keyword(s):

Antimicrobial Activity ◽

Solid State ◽

Physical Stability ◽

Chemical Degradation ◽

Beam Radiation ◽

Promising Alternative ◽

X Ray ◽

Lactam Ring ◽

Ft Ir ◽

Hydroxyethyl Group

The influence of ionising radiation on the physicochemical properties of meropenem trihydrate in solid state was studied for doses of e-beam radiation: 25 kGy and 400 kGy. In the first part of our studies, we evaluated the possibility of applying radiosterilization to obtain sterile meropenem. No changes for meropenem irradiated with a dose of 25 kGy, the dose required to attain sterility, was confirmed in the results of spectroscopic (FT-IR), thermal (DSC, TGA) and X-ray powder diffraction (XRPD) studies. The radiation dose of 25 kGy produces no more than about 1500 ppm of radical defects. The chromatographic studies of irradiated meropenem in solutions did not show any chemical degradation. Moreover, the antimicrobial activity of meropenem irradiated with the dose of 25 kGy was unchanged. Based on the received results, we can conclude that radiostelization is a promising, alternative method for obtaining sterile meropenem. In the second part of the research, meropenem was exposed to e-beam radiation at the 400 kGy dose rate. It was confirmed, that reducing of antimicrobial activity could be connected with the degradation of β-lactam ring and changes in the trans-hydroxyethyl group. Apart from chemical changes, changes in the physical stability of irradiated meropenem (400 kGy) was also observed.

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Efficacy and Improved Resistance Potential of a Cofactor-Independent InhA Inhibitor of Mycobacterium tuberculosis in the C3HeB/FeJ Mouse Model

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02071-18 ◽

2019 ◽

Vol 63 (4) ◽

Cited By ~ 4

Author(s):

Gregory T. Robertson ◽

Victoria A. Ektnitphong ◽

Michael S. Scherman ◽

Matthew B. McNeil ◽

Devon Dennison ◽

...

Keyword(s):

Mycobacterium Tuberculosis ◽

Mouse Model ◽

Promising Alternative ◽

Lung Lesions ◽

Content Type ◽

Drug Levels ◽

Lower Resistance ◽

Inha Inhibitor

ABSTRACT AN12855 is a direct, cofactor-independent inhibitor of InhA in Mycobacterium tuberculosis. In the C3HeB/FeJ mouse model with caseous necrotic lung lesions, AN12855 proved efficacious with a significantly lower resistance frequency than isoniazid. AN12855 drug levels were better retained in necrotic lesions and caseum where the majority of hard to treat, extracellular bacilli reside. Owing to these combined attributes, AN12855 represents a promising alternative to the frontline antituberculosis agent isoniazid.

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Utilization of recycled hazardous waste bagasse as reinforcement to develop green composite material

World Journal of Engineering ◽

10.1108/wje-03-2019-0069 ◽

2020 ◽

Vol 17 (3) ◽

pp. 399-406 ◽

Cited By ~ 3

Author(s):

Shashi Prakash Dwivedi ◽

Garima Dwivedi

Keyword(s):

Composite Material ◽

Soil Pollution ◽

Matrix Material ◽

Partial Replacement ◽

Green Composite ◽

Waste Products ◽

Ceramic Particles ◽

Content Type ◽

Base Composite ◽

Bagasse Waste

Purpose In the current scenario, air pollution and soil pollution from the industries wastes are one of the major problems all over the world. Further, disposal of these wastes from industries are very costly. However, several attempts were carried out by various researchers in the past to use these wastes. One of the most common waste products is bagasse from sugar industries. These hazardous bagasse wastes lead to air and soil pollution. This study aims to recycle bagasse waste in the development of aluminium base composite as partial replacement of ceramic particles. Design/methodology/approach In the present investigation, recycled bagasse waste was used in the development of aluminium base composite as partial replacement of ceramic particles such as SiC, Al2O3 and B4C. Production industries of these ceramic particles (SiC, B4C and Al2O3) emit huge amount of greenhouse gases such as N2O3, CH4, CO2 and H2O. These green house gases produce lots of environment problem. Furthermore, production of these ceramic particles is also costly. AA6061 aluminium alloy was taken as matrix material. Composite material was developed using the stir casting technique. Findings Microstructure results showed proper distribution of bagasse ash and MgO powder in the aluminium base metal matrix composite. It was notified from analysis that minimum corrosion loss and minimum porosity were found for Al/2.5% bagasse ash/12.5% MgO powder composite. For the same composition, hardness and thermal expansion were also observed better as compared to other selected compositions. However, density and cost of composites continuously decrease by increasing percentage of bagasse ash in development of composite. Originality/value Results showed about 11.30% improvement in tensile strength, 11.64% improvement in specific strength and 40% improvement in hardness by using bagasse ash as reinforcement with MgO powder in development of aluminium base composite.

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Proof-of-Principle Study in a Murine Lung Infection Model of Antipseudomonal Activity of Phage PEV20 in a Dry-Powder Formulation

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01714-17 ◽

2017 ◽

Vol 62 (2) ◽

Cited By ~ 11

Author(s):

Rachel Yoon Kyung Chang ◽

Ke Chen ◽

Jiping Wang ◽

Martin Wallin ◽

Warwick Britton ◽

...

Keyword(s):

Lung Infection ◽

Treated Group ◽

Multidrug Resistant ◽

Resistant Bacteria ◽

Infection Model ◽

Dry Powder ◽

Intratracheal Administration ◽

Promising Alternative ◽

Content Type ◽

Powder Formulation

ABSTRACT Bacteriophage therapy is a promising alternative treatment to antibiotics, as it has been documented to be efficacious against multidrug-resistant bacteria with minimal side effects. Several groups have demonstrated the efficacy of phage suspension in vivo to treat lung infections using intranasal delivery; however, phage dry-powder administration to the lungs has not yet been explored. Powder formulations provide potential advantages over a liquid formulation, including easy storage, transport, and administration. The purpose of this study was to assess the bactericidal activities of phage dry-powder formulations against multidrug-resistant (MDR) strain Pseudomonas aeruginosa FADDI-PA001 in a mouse lung infection model. Phage PEV20 spray dried with lactose and leucine produced an inhalable powder at a concentration of 2 × 107 PFU/mg. P. aeruginosa lung infection was established by intratracheal administration of the bacterial suspension to neutropenic mice. At 2 h after the bacterial challenge, the infected mice were treated with 2 mg of the phage powder using a dry-powder insufflator. At 24 h after the phage treatment, the bacterial load in the lungs was decreased by 5.3 log10 (P < 0.0005) in the phage-treated group compared with that in the nontreated group. Additionally, the phage concentration in the lungs was increased by 1 log10 at 24 h in the treated group. These results demonstrate the feasibility of a pulmonary delivery of phage PEV20 dry-powder formulation for the treatment of lung infection caused by antibiotic-resistant P. aeruginosa.

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A novel nature-inspired optimization based neural network simulator to predict coal grindability index

Engineering Computations ◽

10.1108/ec-09-2017-0332 ◽

2018 ◽

Vol 35 (2) ◽

pp. 1003-1048 ◽

Cited By ~ 5

Author(s):

S. Yazdani ◽

Esmaeil Hadavandi ◽

James Hower ◽

Saeed Chehreh Chelgani

Keyword(s):

Neural Network ◽

Coal Industry ◽

Network Simulator ◽

Promising Alternative ◽

Content Type ◽

Evolutionary Neural Network ◽

Coal Particles ◽

Wide Range ◽

Relative Hardness ◽

Hardgrove Grindability Index

Purpose Hardgrove grindability index (HGI) is an important physical parameter used to demonstrate the relative hardness of coal particles. Modeling of HGI based on coal conventional properties is a quite complicated procedure. The paper aims to develop a new accurate model for prediction of HGI that is called optimized evolutionary neural network (OPENN). Design/methodology/approach The procedure for generation of the proposed OPENN predictive model was performed in two stages. In the first stage, as the high dimensionality involved in the input space, a correlation-based feature selection (CFS) algorithm was used to select the most important influencing variables for HGI prediction. In the second stage, a combination of differential evolution (DE) and biography-based optimization (BBO) algorithms as a global search method were applied to evolve weights of a multi-layer perception neural network. Findings The proposed OPENN was examined and compared with other typical models using a wide range of Kentucky coal samples. The testing results showed that the accuracy of the proposed OPENN model is significantly better than the other typical models and can be considered as a promising alternative for HGI prediction. Originality/value As HGI test is relatively expensive procedure, there is an economical interest on HGI modeling based on coal conventional properties (proximate, ultimate and petrography); the proposed OPENN model to estimate HGI would be a valuable and practical tool for coal industry.

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ClyJ Is a Novel Pneumococcal Chimeric Lysin with a Cysteine- and Histidine-Dependent Amidohydrolase/Peptidase Catalytic Domain

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02043-18 ◽

2019 ◽

Vol 63 (4) ◽

Cited By ~ 4

Author(s):

Hang Yang ◽

Yujing Gong ◽

Huaidong Zhang ◽

Irina Etobayeva ◽

Paulina Miernikiewicz ◽

...

Keyword(s):

Catalytic Domain ◽

High Specificity ◽

Multidrug Resistant ◽

Penicillin G ◽

Dependent Manner ◽

Pneumococcal Infections ◽

Promising Alternative ◽

Content Type ◽

Conventional Antibiotics

ABSTRACT Streptococcus pneumoniae is one of the leading pathogens that cause a variety of mucosal and invasive infections. With the increased emergence of multidrug-resistant S. pneumoniae, new antimicrobials with mechanisms of action different from conventional antibiotics are urgently needed. In this study, we identified a putative lysin (gp20) encoded by the Streptococcus phage SPSL1 using the LytA autolysin as a template. Molecular dissection of gp20 revealed a binding domain (GPB) containing choline-binding repeats (CBRs) that are high specificity for S. pneumoniae. By fusing GPB to the CHAP (cysteine, histidine-dependent amidohydrolase/peptidase) catalytic domain of the PlyC lysin, we constructed a novel chimeric lysin, ClyJ, with improved activity to the pneumococcal Cpl-1 lysin. No resistance was observed in S. pneumoniae strains after exposure to incrementally doubling concentrations of ClyJ for 8 continuous days in vitro. In a mouse bacteremia model using penicillin G as a control, a single intraperitoneal injection of ClyJ improved the survival rate of lethal S. pneumoniae-infected mice in a dose-dependent manner. Given its high lytic activity and safety profile, ClyJ may represent a promising alternative to combat pneumococcal infections.

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Classifying internal audit quality using textual analysis: the case of auditor selection

Managerial Auditing Journal ◽

10.1108/maj-01-2018-1785 ◽

2019 ◽

Vol 34 (8) ◽

pp. 924-950 ◽

Cited By ~ 1

Author(s):

Georgia Boskou ◽

Efstathios Kirkos ◽

Charalambos Spathis

Keyword(s):

Text Mining ◽

Textual Analysis ◽

Audit Quality ◽

Internal Audit ◽

Annual Reports ◽

Financial Indicators ◽

Classification Models ◽

Promising Alternative ◽

Content Type ◽

Auditor Selection

Purpose This paper aims to assess internal audit quality (IAQ) by using automated textual analysis of disclosures of internal audit mechanisms in annual reports. Design/methodology/approach This paper uses seven text mining techniques to construct classification models that predict whether companies listed on the Athens Stock Exchange are audited by a Big 4 firm, an auditor selection that prior research finds is associated with higher IAQ. The classification accuracy of the models is compared to predictions based on financial indicators. Findings The results show that classification models developed using text analysis can be a promising alternative proxy in assessing IAQ. Terms, N-Grams and financial indicators of a company, as they are presented in the annual reports, can provide information on the IAQ. Practical implications This study offers a novel approach to assessing the IAQ by applying textual analysis techniques. These findings are important for those who oversee internal audit activities, assess internal audit performance or want to improve or evaluate internal audit systems, such as managers or audit committees. Practitioners, regulators and investors may also extract useful information on internal audit and internal auditors by using textual analysis. The insights are also relevant for external auditors who are required to consider various aspects of corporate governance, including IAQ. Originality/value IAQ has been the subject of thorough examination. However, this study is the first attempt, to the authors’ knowledge, to introduce an innovative text mining approach utilizing unstructured textual disclosure from annual reports to develop a proxy for IAQ. It contributes to the internal audit field literature by further exploring concerns relevant to IAQ.

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Hydrophobic Gentamicin-Loaded Nanoparticles Are Effective against Brucella melitensis Infection in Mice

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00378-13 ◽

2013 ◽

Vol 57 (7) ◽

pp. 3326-3333 ◽

Cited By ~ 16

Author(s):

Edurne Imbuluzqueta ◽

Carlos Gamazo ◽

Hugo Lana ◽

Miguel Ángel Campanero ◽

David Salas ◽

...

Keyword(s):

Brucella Melitensis ◽

Plga Nanoparticles ◽

Human Brucellosis ◽

Promising Alternative ◽

Content Type ◽

Intracellular Compartments ◽

Sulfosuccinate Sodium ◽

Unit Reduction

ABSTRACTThe clinical management of human brucellosis is still challenging and demandsin vitroactive antibiotics capable of targeting the pathogen-harboring intracellular compartments. A sustained release of the antibiotic at the site of infection would make it possible to reduce the number of required doses and thus the treatment-associated toxicity. In this study, a hydrophobically modified gentamicin, gentamicin-AOT [AOT is bis(2-ethylhexyl) sulfosuccinate sodium salt], was either microstructured or encapsulated in poly(lactic-co-glycolic acid) (PLGA) nanoparticles. The efficacy of the formulations developed was studied bothin vitroandin vivo. Gentamicin formulations reducedBrucellainfection in experimentally infected THP-1 monocytes (>2-log10unit reduction) when using clinically relevant concentrations (18 mg/liter). Moreover,in vivostudies demonstrated that gentamicin-AOT-loaded nanoparticles efficiently targeted the drug both to the liver and the spleen and maintained an antibiotic therapeutic concentration for up to 4 days in both organs. This resulted in an improved efficacy of the antibiotic in experimentally infected mice. Thus, while 14 doses of free gentamicin did not alter the course of the infection, only 4 doses of gentamicin-AOT-loaded nanoparticles reduced the splenic infection by 3.23 logs and eliminated it from 50% of the infected mice with no evidence of adverse toxic effects. These results strongly suggest that PLGA nanoparticles containing chemically modified hydrophobic gentamicin may be a promising alternative for the treatment of human brucellosis.

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Vibrio cholerae VciB Mediates Iron Reduction

Journal of Bacteriology ◽

10.1128/jb.00874-16 ◽

2017 ◽

Vol 199 (12) ◽

Cited By ~ 6

Author(s):

Eric D. Peng ◽

Shelley M. Payne

Keyword(s):

Electron Transport ◽

Vibrio Cholerae ◽

Ferrous Iron ◽

Electron Transport Chain ◽

Iron Reduction ◽

Iron Transport ◽

Ferric Iron ◽

Transport Systems ◽

Content Type ◽

Transport Chain

ABSTRACT Vibrio cholerae is the causative agent of the severe diarrheal disease cholera. V. cholerae thrives within the human host, where it replicates to high numbers, but it also persists within the aquatic environments of ocean and brackish water. To survive within these nutritionally diverse environments, V. cholerae must encode the necessary tools to acquire the essential nutrient iron in all forms it may encounter. A prior study of systems involved in iron transport in V. cholerae revealed the existence of vciB, which, while unable to directly transport iron, stimulates the transport of iron through ferrous (Fe2+) iron transport systems. We demonstrate here a role for VciB in V. cholerae in which VciB stimulates the reduction of Fe3+ to Fe2+, which can be subsequently transported into the cell with the ferrous iron transporter Feo. Iron reduction is independent of functional iron transport but is associated with the electron transport chain. Comparative analysis of VciB orthologs suggests a similar role for other proteins in the VciB family. Our data indicate that VciB is a dimer located in the inner membrane with three transmembrane segments and a large periplasmic loop. Directed mutagenesis of the protein reveals two highly conserved histidine residues required for function. Taken together, our results support a model whereby VciB reduces ferric iron using energy from the electron transport chain. IMPORTANCE Vibrio cholerae is a prolific human pathogen and environmental organism. The acquisition of essential nutrients such as iron is critical for replication, and V. cholerae encodes a number of mechanisms to use iron from diverse environments. Here, we describe the V. cholerae protein VciB that increases the reduction of oxidized ferric iron (Fe3+) to the ferrous form (Fe2+), thus promoting iron acquisition through ferrous iron transporters. Analysis of VciB orthologs in Burkholderia and Aeromonas spp. suggest that they have a similar activity, allowing a functional assignment for this previously uncharacterized protein family. This study builds upon our understanding of proteins known to mediate iron reduction in bacteria.

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