Ferrous Campylobacter jejuni truncated hemoglobin P displays an extremely high reactivity for cyanide - A comparative study

Campylobacter jejuni hosts two hemoglobins (Hbs). The Camplylobacter jejuni single-domain Hb (called Cgb) is homologous to the globin domain of flavohemoglobin, and it has been proposed to protect the bacterium against nitrosative stress. The second Hb is called Ctb (hereafter Cj-trHbP), belongs to truncated Hb group III, and has been hypothesized to be involved in O 2 chemistry. Here, the kinetics and thermodynamics of cyanide binding to ferric and ferrous Cj-trHbP [Cj-trHbP(III) and Cj-trHbP(II), respectively] are reported and analyzed in parallel with those of related heme proteins, with particular reference to those from Mycobacterium tuberculosis. The affinity of cyanide for Cj-trHbP(II) is higher than that reported for any known (in)vertebrate globin by more than three orders of magnitude (K = 1.2 × 10-6 m). This can be fully attributed to the highest (ever observed for a ferrous Hb) cyanide-binding association rate constant (kon = 3.3 × 103 m-1·s-1), even though the binding process displays a rate-limiting step (kmax = 9.1 s -1). Cj-trHbP(III) shows a very high affinity for cyanide (L = 5.8 × 10-9 m); however, cyanide association kinetics are independent of cyanide concentration, displaying a rate-limiting step (l max = 2.0 × 10-3 s-1). Values of the first-order rate constant for cyanide dissociation from Cj-trHbP(II)-cyanide and Cj-trHbP(III)-cyanide (koff =5.0 × 10-3 s -1 and loff ≥ 1 × 10-4 s-1, respectively) are similar to those reported for (in)vertebrate globins. The very high affinity of cyanide for Cj-trHbP(II), reminiscent of that of horseradish peroxidase(II), suggests that this globin may participate in cyanide detoxification. © 2008 The Authors

Analysis and tests of TF magnet insulation samples for the JET upgrade to 4 tesla

The JET Toroidal Field (TF) coils were originally designed for operation at 3.4 tesla. In order to upgrade the field to 4 tesla and thus improve the performance of the JET machine, new mechanical tests and analysis were carried out on the insulation of TF coil samples. They are aimed at investigating the mechanical properties and the status of the insulation in order to set allowable stresses and force limits. In particular since the shear stress in the insulation is strongly affected by the shear modulus of elasticity G, it is important to measure this parameter. A method for the measurement of G in glass-resin fibres, the V-notched beam method (Iosipescu method) , was applied. The particular shape of the rectangular Iosipescu V- notched sample and the particular modality of force application produce pure shear stress for a reliable measurement of the G value and of the shear strength of the insulation. The effect of temperature on these mechanical properties was also investigated. Results show higher average shear strength with lower scatter compared with previous tests on conventional rectangular samples, thus confirming the reliability of the method. Micrographic analysis of the insulation and comparison between the straight and curved regions of the magnet, where the highest stress occurs, confirm the good quality of the impregnation of the coil. Glass-resin content, void content, micros and TG measurements have been performed on different samples and correlation between the different properties of the insulation investigated. Moreover fatigue tests at different temperatures were performed and data analyzed with the cumulative damage technique, which allows for an extrapolation of the fatigue curve with less samples than the standard method. (6 refs)

PENGARUH PENERAPAN TOTAL QUALITY MANAGEMENT (TQM) TERHADAP KINERJA PADA PT. PLN (PERSERO) DISTRIBUSI JAWA TIMUR

PT. PLN (Persero) Distribusi Jawa Timur is one of the main implementing unit under PT. PLN (Persero) is engaged in the distribution and sale of electric power in East Java. Achievement of organizational performance can be supported by the application of total quality management within the company. Factors that can affect organizational performance are customer focus, top management, employee engagement and empowerment, training education, and continuous improvement. This study aims to examine and analyze the effect of total quality management implementation on organizational performance at PT. PLN (Persero) Distribusi Jawa Timur. Type of research with method of quantitative approach. The sample in this study amounted to 83 respondents PT. PLN (Persero) Distribusi Jawa Timur with sampling technique that is slovin method. Statistical analysis used in this study is multiple linear regression with the help of SPSS Version 21 program. The result of this study explains the focus of customer positively influence to organizational performance, top management have positive effect on organizational performance, involvement and empowerment have positive effect to organizational performance, training education have positive effect to organizational performance, continuous improvement have positive effect to organizational performance, total quality management simultaneously have a positive effect on organizational performance. Keywords : total quality management, organizational performance

Editorial: XXXIII SIMGBM Congress 2019 - Antimicrobials and Host-Pathogen Interactions

This Research Topic (RT) is intended to provide a collection of selected contributions in the broad area “Antimicrobials and Host-Pathogen Interactions” from the participants of “Microbiology 2019” congress organized by the Italian Society for General Microbiology and Microbial Biotechnology (SIMGBM, www.simgbm.it), which was held in Florence, Italy, on June 19–22, 2019. The congress was attended by 224 scientists from all over the world, and contributions relevant to this RT were collected from presentations in the following congress sessions: (i) Antibiotic resistome: where do antibiotic resistance genes come from? (ii) New antimicrobial strategies in the post-antibiotic era; (iii) Intercellular communication in host-pathogen interactions; (iv) New approaches to unravel fungal-host interactions; (v) Bacterial cell surface and signaling. The unifying concept of this RT originates from the increasing awareness that antimicrobial resistance (AMR) is a complex problem which should be addressed by a multifocal approach. Fundamental microbiological investigations in this direction involve understanding of the flow of AMR genes from the environment to human and animal pathogens, the development of new drugs to tackle AMR, and the discovery of new druggable targets to impairmicrobial growth and/or pathogenicity

Performance of the CMS Cathode Strip Chambers with Cosmic Rays

The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 microns to 243 microns. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns

Unravelling the genome-wide contributions of specific 2-alkyl-4-quinolones and PqsE to quorum sensing in Pseudomonas aeruginosa

The pqs quorum sensing (QS) system is crucial for Pseudomonas aeruginosa virulence both in vitro and in animal models of infection and is considered an ideal target for the development of anti-virulence agents. However, the precise role played by each individual component of this complex QS circuit in the control of virulence remains to be elucidated. Key components of the pqs QS system are 2-heptyl-4-hydroxyquinoline (HHQ), 2-heptyl-3-hydroxy-4-quinolone (PQS), 2-heptyl-4-hydroxyquinoline N-oxide (HQNO), the transcriptional regulator PqsR and the PQS-effector element PqsE. To define the individual contribution of each of these components to QS-mediated regulation, transcriptomic analyses were performed and validated on engineered P. aeruginosa strains in which the biosynthesis of 2-alkyl 4-quinolones (AQs) and expression of pqsE and pqsR have been uncoupled, facilitating the identification of the genes controlled by individual pqs system components. The results obtained demonstrate that i) the PQS biosynthetic precursor HHQ triggers a PqsR-dependent positive feedback loop that leads to the increased expression of only the pqsABCDE operon, ii) PqsE is involved in the regulation of diverse genes coding for key virulence determinants and biofilm development, iii) PQS promotes AQ biosynthesis, the expression of genes involved in the iron-starvation response and virulence factor production via PqsR-dependent and PqsR-independent pathways, and iv) HQNO does not influence transcription and hence does not function as a QS signal molecule. Overall this work has facilitated identification of the specific regulons controlled by individual pqs system components and uncovered the ability of PQS to contribute to gene regulation independent of both its ability to activate PqsR and to induce the iron-starvation response

PENGARUH PENERAPAN TOTAL QUALITY MANAGEMENT (TQM) TERHADAP KINERJA PADA PT. PLN (PERSERO) DISTRIBUSI JAWA TIMUR

PT. PLN (Persero) Distribusi Jawa Timur is one of the main implementing unit under PT. PLN (Persero) is engaged in the distribution and sale of electric power in East Java. Achievement of organizational performance can be supported by the application of total quality management within the company. Factors that can affect organizational performance are customer focus, top management, employee engagement and empowerment, training education, and continuous improvement. This study aims to examine and analyze the effect of total quality management implementation on organizational performance at PT. PLN (Persero) Distribusi Jawa Timur. Type of research with method of quantitative approach. The sample in this study amounted to 83 respondents PT. PLN (Persero) Distribusi Jawa Timur with sampling technique that is slovin method. Statistical analysis used in this study is multiple linear regression with the help of SPSS Version 21 program. The result of this study explains the focus of customer positively influence to organizational performance, top management have positive effect on organizational performance, involvement and empowerment have positive effect to organizational performance, training education have positive effect to organizational performance, continuous improvement have positive effect to organizational performance, total quality management simultaneously have a positive effect on organizational performance. Keywords : total quality management, organizational performance

Susceptibility testing of colistin for acinetobacter baumannii: How far are we from the truth?

Acinetobacter baumannii is involved in life-threatening nosocomial infections, mainly in the intensive care units (ICUs), and often colistin may represent the last therapeutic opportunity. The susceptibility to colistin of 51 epidemiologically typed A. baumannii strains isolated in 2017 from clinical samples of patients hospitalized in the ICU of a tertiary care academic hospital was investigated. All isolates were carbapenem-resistant due to the presence of the blaOXA-23 gene in sequence group 1 (international clonal lineage II) and sequence group 4 (related to international clonal lineage II) isolates, and to the blaOXA-24/40 gene in sequence group 2 (international clonal lineage I) isolates. Vitek®2, agar diffusion, and broth microdilution tests showed major discordancy (≥2 dilution factors) in the minimum inhibitory concentration (MIC) values for colistin in 24 out of 51 isolates, resulting in erroneous reporting of qualitative susceptibility data for eight isolates. In growth kinetics experiments in the presence of colistin, five isolates grew with drug concentrations above the susceptibility breakpoint when incubated for >12 h, and three isolates showed the presence of heteroresistant subpopulations. This study highlights that the high frequency of isolation of carbapenem-resistant A. baumannii strains in high-risk infectious wards requires an accurate application of methods for detecting susceptibility to antibiotics, in particular to colistin, so as to ensure a correct therapeutic approach

Performance and Operation of the CMS Electromagnetic Calorimeter

The operation and general performance of the CMS electromagnetic calorimeter using cosmic-ray muons are described. These muons were recorded after the closure of the CMS detector in late 2008. The calorimeter is made of lead tungstate crystals and the overall status of the 75848 channels corresponding to the barrel and endcap detectors is reported. The stability of crucial operational parameters, such as high voltage, temperature and electronic noise, is summarised and the performance of the light monitoring system is presented

Brittle asthma: still on board?

(1) Background: “Brittle Asthma” was considered an asthma clinical phenotype and deemed to be life-threatening in the early 2000s; then, this definition disappeared. The purpose of this review is to examine what has historically been referred to as this term and see whether it may be applied to modern clinical practice, thus acquiring fresh relevance and meaning. (2) Methods: A non-systematic search of the literature was conducted using both MeSH and free-text phrases. No limitations on the research design or type of publication were applied. (3) Results: Reliable data regarding “Brittle Asthma” are lacking due to the paucity of current data and the few studies available. After a few years of reworking, it was divided into two sub-classes: one characterized by a wide PEF variability despite high-dose therapy and the other by sudden acute attacks in otherwise apparently normal airway functions or well-controlled asthma. Their characteristics were hardly defined because of their low prevalence. Data regarding risk factors, atopy, mechanisms, and treatments were analyzed. (4) Conclusions: Over time, different terminology has been introduced to define asthma severity and control. It would be worth investigating whether the term “Brittle Asthma” previously used may be helpful to find new hints to stratify patients and improve disease management