scholarly journals Full Molecular Typing of Neisseria meningitidis Directly from Clinical Specimens for Outbreak Investigation

2020 ◽  
Vol 58 (12) ◽  
Author(s):  
Mark Itsko ◽  
Adam C. Retchless ◽  
Sandeep J. Joseph ◽  
Abigail Norris Turner ◽  
Jose A. Bazan ◽  
...  
Keyword(s):  
Neisseria Meningitidis ◽  
Molecular Typing ◽  
De Novo ◽  
Multiple Displacement Amplification ◽  
Low Cost ◽  
Vaccine Antigen ◽  
Content Type ◽  
Clinical Specimens ◽  
Low Culture

ABSTRACT Neisseria meningitidis is a leading cause of bacterial meningitis and sepsis worldwide and an occasional cause of meningococcal urethritis. When isolates are unavailable for surveillance or outbreak investigations, molecular characterization of pathogens needs to be performed directly from clinical specimens, such as cerebrospinal fluid (CSF), blood, or urine. However, genome sequencing of specimens is challenging because of low bacterial and high human DNA abundances. We developed selective whole-genome amplification (SWGA), an isothermal multiple-displacement amplification-based method, to efficiently enrich, sequence, and de novo assemble N. meningitidis DNA from clinical specimens with low bacterial loads. SWGA was validated with 12 CSF specimens from invasive meningococcal disease cases and 12 urine specimens from meningococcal urethritis cases. SWGA increased the mean proportion of N. meningitidis reads by 2 to 3 orders of magnitude, enabling identification of at least 90% of the 1,605 N. meningitidis core genome loci for 50% of the specimens. The validated method was used to investigate two meningitis outbreaks recently reported in Togo and Burkina Faso. Twenty-seven specimens with low bacterial loads were processed by SWGA before sequencing, and 12 of 27 were successfully assembled to obtain the full molecular typing and vaccine antigen profile of the N. meningitidis pathogen, thus enabling thorough characterization of outbreaks. This method is particularly important for enhancing molecular surveillance in regions with low culture rates. SWGA produces enough reads for phylogenetic and allelic analysis at a low cost. More importantly, the procedure can be extended to enrich other important human bacterial pathogens.

scholarly journals Characterization of Neisseria meningitidis Isolates That Do Not Express the Virulence Factor and Vaccine Antigen Factor H Binding Protein

2011 ◽  
Vol 18 (6) ◽  
pp. 1002-1014 ◽  
Author(s):  
Jay Lucidarme ◽  
Lionel Tan ◽  
Rachel M. Exley ◽  
Jamie Findlow ◽  
Ray Borrow ◽  
...  
Keyword(s):  
Neisseria Meningitidis ◽  
Binding Protein ◽  
Factor H ◽  
Negative Regulator ◽  
Vaccine Antigen ◽  
Natural Immunity ◽  
Content Type ◽  
Reading Frame ◽  
Flanking Sequences

ABSTRACTNeisseria meningitidisremains a leading cause of bacterial sepsis and meningitis. Complement is a key component of natural immunity against this important human pathogen, which has evolved multiple mechanisms to evade complement-mediated lysis. One approach adopted by the meningococcus is to recruit a human negative regulator of the complement system, factor H (fH), to its surface via a lipoprotein, factor H binding protein (fHbp). Additionally, fHbp is a key antigen in vaccines currently being evaluated in clinical trials. Here we characterize strains ofN. meningitidisfrom several distinct clonal complexes which do not express fHbp; all strains were recovered from patients with disseminated meningococcal disease. We demonstrate that these strains have either a frameshift mutation in thefHbpopen reading frame or have entirely lostfHbpand some flanking sequences. No fH binding was detected to other ligands among thefHbp-negative strains. The implications of these findings for meningococcal pathogenesis and prevention are discussed.

PLA conductive filament for 3D printed smart sensing applications

2018 ◽  
Vol 24 (4) ◽  
pp. 739-743 ◽  
Author(s):  
Simone Luigi Marasso ◽  
Matteo Cocuzza ◽  
Valentina Bertana ◽  
Francesco Perrucci ◽  
Alessio Tommasi ◽  
...  
Keyword(s):  
Temperature Sensor ◽  
Low Cost ◽  
Conductive Polymer ◽  
Temperature Characteristic ◽  
Temperature Sensors ◽  
Electrical Performance ◽  
Content Type ◽  
Sensing Applications ◽  
3D Printed

Purpose This paper aims to present a study on a commercial conductive polylactic acid (PLA) filament and its potential application in a three-dimensional (3D) printed smart cap embedding a resistive temperature sensor made of this material. The final aim of this study is to add a fundamental block to the electrical characterization of printed conductive polymers, which are promising to mimic the electrical performance of metals and semiconductors. The studied PLA filament demonstrates not only to be suitable for a simple 3D printed concept but also to show peculiar characteristics that can be exploited to fabricate freeform low-cost temperature sensors. Design/methodology/approach The first part is focused on the conductive properties of the PLA filament and its temperature dependency. After obtaining a resistance temperature characteristic of this material, the same was used to fabricate a part of a 3D printed smart cap. Findings An approach to the characterization of the 3D printed conductive polymer has been presented. The major results are related to the definition of resistance vs temperature characteristic of the material. This model was then exploited to design a temperature sensor embedded in a 3D printed smart cap. Practical implications This study demonstrates that commercial conductive PLA filaments can be suitable materials for 3D printed low-cost temperature sensors or constitutive parts of a 3D printed smart object. Originality/value The paper clearly demonstrates that a new generation of 3D printed smart objects can already be obtained using low-cost commercial materials.

scholarly journals Complementation of Cobalamin Auxotrophy in Synechococcus sp. Strain PCC 7002 and Validation of a Putative Cobalamin RiboswitchIn Vivo

2016 ◽  
Vol 198 (19) ◽  
pp. 2743-2752 ◽  
Author(s):  
Adam A. Pérez ◽  
Zhenfeng Liu ◽  
Dmitry A. Rodionov ◽  
Zhongkui Li ◽  
Donald A. Bryant
Keyword(s):  
Large Scale ◽  
De Novo ◽  
Expression System ◽  
Industrial Applications ◽  
Methionine Synthase ◽  
Methionine Biosynthesis ◽  
Content Type ◽  
Methyl Donor ◽  
Synechococcus Sp

ABSTRACTThe euryhaline cyanobacteriumSynechococcussp. strain PCC 7002 has an obligate requirement for exogenous vitamin B12(cobalamin), but little is known about the roles of this compound in cyanobacteria. Bioinformatic analyses suggest that only the terminal enzyme in methionine biosynthesis, methionine synthase, requires cobalamin as a coenzyme inSynechococcussp. strain PCC 7002. Methionine synthase (MetH) catalyzes the transfer of a methyl group fromN5-methyl-5,6,7,8-tetrahydrofolate tol-homocysteine duringl-methionine synthesis and uses methylcobalamin as an intermediate methyl donor. Numerous bacteria and plants alternatively employ a cobalamin-independent methionine synthase isozyme, MetE, that catalyzes the same methyl transfer reaction as MetH but usesN5-methyl-5,6,7,8-tetrahydrofolate directly as the methyl donor. The cobalamin auxotrophy ofSynechococcussp. strain PCC 7002 was complemented by using themetEgene from the closely related cyanobacteriumSynechococcussp. strain PCC 73109, which possesses genes for both methionine synthases. This result suggests that methionine biosynthesis is probably the sole use of cobalamin inSynechococcussp. strain PCC 7002. Furthermore, a cobalamin-repressible gene expression system was developed inSynechococcussp. strain PCC 7002 that was used to validate the presence of a cobalamin riboswitch in the promoter region ofmetEfromSynechococcussp. strain PCC 73109. This riboswitch acts as a cobalamin-dependent transcriptional attenuator formetEin that organism.IMPORTANCESynechococcussp. strain PCC 7002 is a cobalamin auxotroph because, like eukaryotic marine algae, it uses a cobalamin-dependent methionine synthase (MetH) for the final step ofl-methionine biosynthesis but cannot synthesize cobalaminde novo. Heterologous expression ofmetE, encoding cobalamin-independent methionine synthase, fromSynechococcussp. strain PCC 73109, relieved this auxotrophy and enabled the construction of a truly autotrophicSynechococcussp. strain PCC 7002 more suitable for large-scale industrial applications. Characterization of a cobalamin riboswitch expands the genetic toolbox forSynechococcussp. strain PCC 7002 by providing a cobalamin-repressible expression system.

scholarly journals Determination of serotyping antigens, clonal analysis and genetic characterization of the 4CMenB vaccine antigen genes in invasive Neisseria meningitidis from Western Canada, 2009 to 2013

2014 ◽  
Vol 63 (11) ◽  
pp. 1490-1499 ◽  
Author(s):  
Dennis K. S. Law ◽  
Jianwei Zhou ◽  
Saul Deng ◽  
Linda Hoang ◽  
Gregory Tyrrell ◽  
...  
Keyword(s):  
Neisseria Meningitidis ◽  
Clonal Complex ◽  
Factor H ◽  
Vaccine Antigen ◽  
Western Canada ◽  
Antigenic Analysis ◽  
Clonal Nature ◽  
4Cmenb Vaccine

This study examined invasive Neisseria meningitidis recovered from invasive meningococcal disease (IMD) cases in Western Canada between 2009 and 2013. A total of 161 isolates from individual IMD cases were analysed for serogroup, serotype, serosubtype, PorA genotype, multi-locus sequence type and nucleotide sequence of their 4CMenB vaccine antigen genes. Sixty-nine isolates were serogroup B (MenB), 47 were serogroup Y (MenY), 22 were serogroup C (MenC), 19 were serogroup W (MenW), three were serogroup E and one was non-encapsulated. MenC, MenY and MenW were mainly clonal, represented primarily by clonal complex (cc) 11, cc23 or cc167, and cc22, respectively. In contrast, MenB were composed of eight different ccs together with 11 isolates not assigned to any known cc. Antigenic analysis and PorA genotyping confirmed the heterogeneity of MenB isolates, while such results supported the clonal nature of most MenC, MenY and MenW isolates. Thirty-four (21.1 %) isolates had at least one gene that encoded one matching vaccine protein component of the 4CMenB vaccine (i.e. PorA P1.4; fHbp variant 1.1; NHBA peptide 2; and NadA-1, -2, or -3). An additional 18 isolates had genes that encoded variant 1 or subfamily B factor H binding proteins of this same vaccine.

scholarly journals Development and Characterization of SSR Markers in the Gossypium Barbadense Genome

2021 ◽  
Author(s):  
Wenjuan ZHONG ◽  
Can YUAN ◽  
Zhengjie CHEN ◽  
Yonghang ZHOU ◽  
Siwei Chen ◽  
...  
Keyword(s):  
Ssr Markers ◽  
De Novo ◽  
Low Cost ◽  
Fiber Quality ◽  
Gossypium Barbadense ◽  
Pcr Analysis ◽  
Genetic Studies ◽  
Genome Wide ◽  
User Friendly

Abstract BackgroundThe fiber quality and resistance traits of Gossypium barbadense are considerably better than that of other Gossypium species. Simple sequence repeats (SSRs) are user friendly, low cost markers widely used in genetic studies. However, most SSRs have been developed from G. hirsutum, G. arboreum, and G. raimondii; no genome-wide SSRs have been developed from G. barbadense.The de novo sequences of G. barbadense cv. Xinhai21 were utilized to develop SSR markers and scanned to detect SSRs using the MIcroSAtellite (http://pgrc.ipk-gatersleben.de/misa/) identification tool. And then in silico PCR analysis was conducted to evaluate these primers polymorphism in five Gossypium species.ResultsIn total, 85,582 SSRs were identified with different motifs. 153,560 primer pairs were successfully designed for 73,419 SSRs. In silico analysis, we found that 8,466 primer pairs of 3,288 SSRs yielded one product (monomorphic) simultaneously in five Gossypium species. two Gossypium species (30 G. hirsutum and 27 G. barbadense accessions) were successfully separated by 300 primer pairs with the polymorphism information content (PIC) ranging from 0.00 to 0.93. ConclusionThese newly developed SSR markers will be helpful for the construction of genetic linkage maps, genetic diversity analyses, QTL mapping, and molecular breeding of Gossypium species.

An overview: characterization of natural fiber reinforced hybrid composites

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
M. Balasubramanian ◽  
Thozhuvur Govindaraman Loganathan ◽  
R. Srimath
Keyword(s):  
Natural Fiber ◽  
Hybrid Composites ◽  
Low Cost ◽  
Research Work ◽  
Tensile Modulus ◽  
Fiber Reinforced ◽  
Content Type ◽  
Specific Strength ◽  
Wide Range

Purpose The purpose of this study is to understand the behavior of hybrid bio-composites under varied applications. Design/methodology/approach Fabrication methods and material characterization of various hybrid bio-composites are analyzed by studying the tensile, impact, flexural and hardness of the same. The natural fiber is a manufactured group of assembly of big or short bundles of fiber to produce one or more layers of flat sheets. The natural fiber-reinforced composite materials offer a wide range of properties that are suitable for many engineering-related fields like aerospace, automotive areas. The main characteristics of natural fiber composites are durability, low cost, low weight, high specific strength and equally good mechanical properties. Findings The tensile properties like tensile strength and tensile modulus of flax/hemp/sisal/Coir/Palmyra fiber-reinforced composites are majorly dependent on the chemical treatment and catalyst usage with fiber. The flexural properties of flax/hemp/sisal/coir/Palmyra are greatly dependent on fiber orientation and fiber length. Impact properties of flax/hemp/sisal/coir/Palmyra are depended on the fiber content, composition and orientation of various fibers. Originality/value This study is a review of various research work done on the natural fiber bio-composites exhibiting the factors to be considered for specific load conditions.

Mycobacterium iranicum sp. nov., a rapidly growing scotochromogenic species isolated from clinical specimens on three different continents

2013 ◽  
Vol 63 (Pt_4) ◽  
pp. 1383-1389 ◽  
Author(s):  
Hasan Shojaei ◽  
Charles Daley ◽  
Zoe Gitti ◽  
Abodolrazagh Hashemi ◽  
Parvin Heidarieh ◽  
...  
Keyword(s):  
Novel Species ◽  
Rrna Gene ◽  
Phenotypic Data ◽  
Content Type ◽  
Clinical Specimens ◽  
Isolation And Characterization ◽  
Genes Encoding ◽  
The Usa ◽  
The 16S Rrna Gene

The isolation and characterization of a novel, rapidly growing, scotochromogenic mycobacterial species is reported. Eight independent strains were isolated from clinical specimens from six different countries of the world, two in Iran, two in Italy and one in each of following countries: Greece, the Netherlands, Sweden and the USA. Interestingly, two of the strains were isolated from cerebrospinal fluid. The strains were characterized by rapid growth and presented orange-pigmented scotochromogenic colonies. DNA-based analysis revealed unique sequences in the four regions investigated: the 16S rRNA gene, the rRNA gene internal transcribed spacer 1 and the genes encoding the 65 kDa heat-shock protein and the beta-subunit of RNA polymerase. The phylogenetic analysis placed the strains among the rapidly growing mycobacteria, being most closely related to Mycobacterium gilvum . The genotypic and phenotypic data both strongly supported the inclusion of the strains investigated here as members of a novel species within the genus Mycobacterium; the name Mycobacterium iranicum sp. nov. is proposed to indicate the isolation in Iran of the first recognized strains. The type strain is M05T ( = DSM 45541T = CCUG 62053T = JCM 17461T).

scholarly journals Genotypic and Phenotypic Characterization of theO-Linked Protein Glycosylation System Reveals High Glycan Diversity in Paired Meningococcal Carriage Isolates

2018 ◽  
Vol 200 (16) ◽  
Author(s):  
Bente Børud ◽  
Guro K. Bårnes ◽  
Ola Brønstad Brynildsrud ◽  
Elisabeth Fritzsønn ◽  
Dominique A. Caugant
Keyword(s):  
Neisseria Meningitidis ◽  
Phase Variation ◽  
Protein Glycosylation ◽  
Phase Variable ◽  
Upper Respiratory Tract ◽  
Content Type ◽  
Variable Expression ◽  
Evolutionary Forces ◽  
Strain Collection

ABSTRACTSpecies within the genusNeisseriadisplay significant glycan diversity associated with theO-linked protein glycosylation (pgl) systems due to phase variation and polymorphic genes and gene content. The aim of this study was to examine in detail thepglgenotype and glycosylation phenotype in meningococcal isolates and the changes occurring during short-term asymptomatic carriage. Paired meningococcal isolates derived from 50 asymptomatic meningococcal carriers, taken about 2 months apart, were analyzed with whole-genome sequencing. TheO-linked protein glycosylation genes were characterized in detail using the Genome Comparator tool at the https://pubmlst.org/ database. Immunoblotting with glycan-specific antibodies (Abs) was used to investigate the protein glycosylation phenotype. All majorpgllocus polymorphisms identified inNeisseria meningitidisto date were present in our isolate collection, with the variable presence ofpglGandpglH, both in combination with eitherpglBorpglB2. We identified significant changes and diversity in thepglgenotype and/or glycan phenotype in 96% of the paired isolates. There was also a high degree of glycan microheterogeneity, in which different variants of glycan structures were found at a given glycoprotein. The main mechanism responsible for the observed differences was phase-variable expression of the involved glycosyltransferases and theO-acetyltransferase. To our knowledge, this is the first characterization of thepglgenotype and glycosylation phenotype in a larger strain collection. This report thus provides important insight into glycan diversity inN. meningitidisand into the phase variability changes that influence the expressed glycoform repertoire during meningococcal carriage.IMPORTANCEBacterial meningitis is a serious global health problem, and one of the major causative organisms isNeisseria meningitidis, which is also a common commensal in the upper respiratory tract of healthy humans. In bacteria, numerous loci involved in biosynthesis of surface-exposed antigenic structures that are involved in the interaction between bacteria and host are frequently subjected to homologous recombination and phase variation. These mechanisms are well described inNeisseria, and phase variation provides the ability to change these structures reversibly in response to the environment. Protein glycosylation systems are becoming widely identified in bacteria, and yet little is known about the mechanisms and evolutionary forces influencing glycan composition during carriage and disease.

scholarly journals Anticorrosive paint with a modified zeolite as functional pigment for SAE 1010 steel protection

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Oriana D'Alessandro ◽  
Christian Eduardo Byrne ◽  
Gonzalo Selmi ◽  
Cecilia Deyá
Keyword(s):  
Low Cost ◽  
Content Type ◽  
Metal Structures ◽  
Steel Protection ◽  
Anticorrosive Pigments ◽  
Noise Measurements ◽  
Inhibitory Efficiency ◽  
Corrosive Environments ◽  
Practical Implications

Purpose This paper aims to formulate and prepare a series of alkyd paints with new anticorrosive pigments, eco-friendly to the environment, based on a natural zeolitic rock modified by ion exchange to incorporate passivating cations. Design/methodology/approach The electrochemical characterization of the painted steel was carried out by conductivity measurements, linear polarization tests, measurements of the corrosion potential and electrochemical noise measurements. Besides, accelerated tests in standard environmental chambers were also carried out. Findings The results show that clinoptilolite–mordenite-based pigments incorporated in the paint provide acceptable anticorrosive properties, taking into account their low environmental impact and the use of a natural resource of low cost. The inhibitory efficiency of ZLa is higher than 80% and of ZPr is close to 70%. The electrochemical assays of the coated panels with the alkyd paints ZLa and ZPr shows similar behavior. Research limitations/implications In this work, good results were obtained with an alkyd resin, but other resins could be tested. Paints could also be formulated with modified zeolites as a complement to others traditional anticorrosive pigments. Practical implications These paints could be used for the protection of metal structures in low corrosive environments. Originality/value There are not many published works using zeolites as anticorrosive pigments.

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