Thermoelectric Properties in Silver Chloride-Alkali Chloride Fused Mixtures

Abstract The initial thermoelectric power of the molten salt mixtures (Ag + Me)Cl (Me = Li, Na, Rb, Cs) has been measured at various temperatures around 800 °C using a silver electrode thermocell. In addition the thermoelectric power of molten pure AgCl is reported. These data have been used to obtain relative values of the heats of transport of the alkali cations in pure salts. Moreover the global behaviour of these mixtures in respect to an ideal model for the heat and electricity transport is discussed

Evaluation of the Uro-Quick system for antibiotic susceptibility tests of strains collected from intensive care units

During the period January–June 2004, 525 pathogens isolated from intensive care units were examined with the new rapid Uro-Quick method for antibiotic susceptibility tests. The results were compared with those obtained by the reference NCCLS methods (disk diffusion or dilution). Antibiotic (in appropriate concentration) was introduced in a vial containing 2 ml of Mueller-Hin ton broth, then 0.5 ml of 5×10 or 106 cells/ml of the strain culture were added. After 3–6 h of incubation, depending on the microorganism studied, the instrument printed the results: no growth and a growth curve similar to that of the untreated control are representative of a susceptible and resistant strain respectively. The following drugs were tested: ciprofloxacin, ampicillin, aztreonam, co-clavulanate, piperacillin/tazobactam, ceftazidime, cefotaxime, cefuroxime, ceftriaxone, imipenem, amikacin, gentamicin, trimethoprim-sulfamethoxazole, clindamycin, erythromycin, linezolid, penicillin, tetracycline, vancomycin, oxacillin. Gram-negative strains tested were 252 and Gram-positive 273: agreement between the two methods ranged from 85.6% (piperacillin/tazobactam) to 98.5% (ciprofloxact) in Gram-negative pathogens, from 90 to 100% in Gram-positive, with the exception of erythromycin (84.2%) against enterococci. On the basis of the present findings the Uro-Quick system appears to be very useful for the rapid detection of antibiotic susceptibility in pathogens collected from intensive care units

Vibrio cholerae interactions with Mytilus galloprovincialis hemocytes mediated by serum components

Edible bivalves (e.g., mussels, oysters) can accumulate large amount of bacteria in their tissues and act as passive carriers of pathogens to humans. Bacterial persistence inside bivalves depends, at least in part, on hemolymph anti-bacterial activity that is exerted by both serum soluble factors and phagocytic cells (i.e., the hemocytes). It was previously shown that Mytilus galloprovincialis hemolymph serum contains opsonins that mediate D-mannose-sensitive interactions between hemocytes and Vibrio cholerae O1 El Tor bacteria that carry the mannose-sensitive hemagglutinin (MSHA). These opsonins enhance phagocytosis and killing of vibrios by facilitating their binding to hemocytes. Since V. cholerae strains not carrying the MSHA ligand (O1 classical, non-O1/O139) are present in coastal water and can be entrapped by mussels, we studied whether in mussel serum, in addition to opsonins directed toward MSHA, other components can mediate opsonization of these bacteria. By comparing interactions of O1 classical and non-O1/O139 strains with hemocytes in artificial sea water and serum, it was found that M. galloprovincialis serum contains components that increase by at approximately twofold their adhesion to, association with, and killing by hemocytes. Experiments conducted with high and low molecular mass fractions obtained by serum ultrafiltration indicated that these compounds have molecular mass higher than 5000 Da. Serum exposure to high temperature (80°C) abolished its opsonizing capability suggesting that the involved serum active components are of protein nature. Further studies are needed to define the chemical properties and specificity of both the involved bacterial ligands and hemolymph opsonins. This information will be central not only to better understand V. cholerae ecology, but also to improve current bivalve depuration practices and properly protect human health

gbpA as a Novel qPCR Target for the Species-Specific Detection of Vibrio cholerae O1, O139, Non-O1/Non-O139 in Environmental, Stool, and Historical Continuous Plankton Recorder Samples

The Vibrio cholerae N-acetyl glucosamine-binding protein A (GbpA) is a chitin-binding protein involved in V . cholerae attachment to environmental chitin surfaces and human intestinal cells. We previously investigated the distribution and genetic variations of gbpA in a large collection of V . cholerae strains and found that the gene is consistently present and highly conserved in this species. Primers and probe were designed from the gbpA sequence of V . cholerae and a new Taq-based qPCR protocol was developed for diagnostic detection and quantification of the bacterium in environmental and stool samples. In addition, the positions of primers targeting the gbpA gene region were selected to obtain a short amplified fragment of 206 bp and the protocol was optimized for the analysis of formalin-fixed samples, such as historical Continuous Plankton Recorder (CPR) samples. Overall, the method is sensitive (50 gene copies), highly specific for V . cholerae and failed to amplify strains of the closely-related species Vibrio mimicus . The sensitivity of the assay applied to environmental and stool samples spiked with V . cholerae ATCC 39315 was comparable to that of pure cultures and was of 10 2 genomic units/l for drinking and seawater samples, 10 1 genomic units/g for sediment and 10 2 genomic units/g for bivalve and stool samples. The method also performs well when tested on artificially formalin-fixed and degraded genomic samples and was able to amplify V . cholerae DNA in historical CPR samples, the earliest of which date back to August 1966. The detection of V . cholerae in CPR samples collected in cholera endemic areas such as the Benguela Current Large Marine Ecosystem (BCLME) is of particular significance and represents a proof of concept for the possible use of the CPR technology and the developed qPCR assay in cholera studies

Effects of Mushroom and Chicory Extracts on the Physiology and Shape of Prevotella intermedia, a Periodontopathogenic Bacterium

Contrary to the common assumption that food has a negative impact on oral health, research has shown that several foods contain a number of components with antibacterial and antiplaque activity. These natural compounds may be useful for improving daily oral hygiene. In this study we evaluate the mode of antimicrobial action of fractions of mushroom and red chicory extracts on Prevotella intermedia, a periodontopathogenic bacterium. The minimal inhibitory concentration corresponded to 0.5x compared to the natural food concentration for both extracts. This concentration resulted in a bacteriostatic effect in mushroom extract and in a slightly bactericidal effect in chicory extract. Cell mass continued to increase even after division stopped. As regards macromolecular synthesis, DNA was almost totally inhibited upon addition of either mushroom or chicory extract, and RNA to a lesser extent, while protein synthesis continued. Cell elongation occurred after septum inhibition as documented by scanning electron microscopy and cell measurement. The morphogenetic effects are reminiscent of the mode of action of antibiotics such as quinolones or β-lactams. The discovery of an antibiotic-like mode of action suggests that these extracts can be advantageously employed for daily oral hygiene in formulations of cosmetic products such as mouthwashes and toothpastes

Testing a Low Molecular Mass Fraction of a Mushroom (Lentinus edodes) Extract Formulated as an Oral Rinse in a Cohort of Volunteers

Although foods are considered enhancing factors for dental caries and periodontitis, laboratory researches indicate that several foods and beverages contain components endowed with antimicrobial and antiplaque activities. A low molecular mass (LMM) fraction of an aqueous mushroom extract has been found to exert these activities in in vitro experiments against potential oral pathogens. We therefore conducted a clinical trial in which we tested an LMM fraction of shiitake mushroom extract formulated in a mouthrinse in 30 young volunteers, comparing the results with those obtained in two identical cohorts, one of which received water (placebo) and the other Listerine. Plaque index, gingival index and bacterial counts in plaque samples were determined in all volunteers over the 11 days of the clinical trial. Statistically significant differences (P < 0.05) were obtained for the plaque index on day 12 in subjects treated with mushroom versus placebo, while for the gingival index significant differences were found for both mushroom versus placebo and mushroom versus Listerine. Decreases in total bacterial counts and in counts of specific oral pathogens were observed for both mushroom extract and Listerine in comparison with placebo. The data suggest that a mushroom extract may prove beneficial in controlling dental caries and/or gingivitis/periodontitis

Control of mother-to-child transmission of Chagas disease: the Tuscany Region model

Chagas disease is an endemic parasitosis in Latin America where the main route of transmission is vectorial. In Europe, due to migration phenomena, Chagas disease cases are increasing and the main way of transmission is mother-to-child, perpetuating the infection from one generation to the other. Congenital Chagas disease is in most cases asymptomatic at birth, but, if not diagnosed and treated early, it puts the child at risk of developing severe cardiac and gastrointestinal problems throughout life. According to the Regional Resolution throughout the territory of Tuscany, pregnant women born in continental Latin America (or born to a mother born in that area) should be offered free of charge serological test for Chagas disease during pregnancy or at delivery, with the main objective of controlling and stopping the transmission of the disease

Human pathogenic vibrios in the aquatic environment: effects of ocean warming

I vibrioni sono batteri Gram negativi, considerati da molti microbiologi la frazione coltivabile pi\uf9 abbondante presente nel mare. Sono indigeni delle acque costiere, dove possono trovarsi in forma libera o adesi a diversi substrati biotici e abiotici tra cui, in particolare, l\u2019esoscheletro chitinoso degli organismi planctonici, che rappresentano una delle principali riserve ambientali di questi batteri. I vibrioni comprendono specie patogene per l\u2019uomo, tra le quali le pi\uf9 importanti sono Vibrio cholerae, Vibrio parahaemolyticus e Vibrio vulnificus. L\u2019aumento della temperatura superficiale dell\u2019acqua di mare (SST), uno degli effetti pi\uf9 evidenti del cambiamento climatico, sembra coinvolto sia nell\u2019espansione geografica dei vibrioni che nell\u2019aumento delle malattie ad essi associate. Ad esempio, \ue8 stato osservato un aumento dell\u2019incidenza dei casi di colera sia in Asia che in Sud America associato all\u2019arrivo della corrente calda di El Ni\uf1o, cos\uec pure alcune anomalie climatiche sono risultate implicate nell\u2019espansione geografica e stagionale delle malattie associate al consumo di prodotti ittici contaminati da V. parahaemolyticus e V. vulnificus. Inoltre, negli ultimi anni, in Nord Europa, \ue8 stato registrato un inaspettato aumento di casi di bagnanti che hanno contratto infezioni sostenute da vibrioni. Nonostante siano stati condotti numerosi studi sugli effetti a lungo termine del riscaldamento delle acque sulle popolazioni eucariotiche, non esistono dati sperimentali sulla risposta dei procarioti marini all\u2019innalzamento della SST. Questa lacuna \ue8 dovuta almeno in parte alla mancanza di dati storici su scala globale. Infatti, i dati ad oggi disponibili sono stati raccolti su scala stagionale e basati su singoli punti di campionamento. Scopo di questo lavoro \ue8 colmare tale lacuna mediante un\u2019analisi molecolare su campioni di plancton fissati in formalina raccolti dal \u201cContinuous Plankton Recorder\u201d (CPR) nel Mar del Nord durante gli ultimi 50 anni. Il CPR rappresenta il pi\uf9 ampio programma di monitoraggio marino al mondo, attuato da oltre 70 anni da \u201cSAHFOS\u201d(UK). Lo strumento CPR, ancorato a navi mercantili, viene trainato ad una profondit\ue0 di ~10 m. Durante tutta la rotta, filtra acqua di mare attraverso un filtro di seta con porosit\ue0 di 270 \u3bcm. Il plancton viene trattenuto dal filtro che, coperto con un secondo filtro, viene arrotolato in una vasca contenente formalina. Poich\ue9 lo zooplancton rappresenta una delle pi\uf9 ampie riserve ambientali di vibrioni, il sistema CPR fornisce la possibilit\ue0 di condurre uno studio retrospettivo sulla presenza e abbondanza dei vibrioni in ambiente acquatico. Il DNA \ue8 stato estratto da un set di 55 campioni di CPR provenienti da due diverse aree del Mar del Nord: foce del Reno e foce dell\u2019Humber. Tutti i campioni sono stati raccolti nel mese di Agosto, tra il 1961 e il 2005. Dopo aver valutato la quantit\ue0 e la qualit\ue0 del DNA estratto, questo \ue8 stato utilizzato per determinare la presenza e l\u2019abbondanza dei vibrioni mediante Real Time PCR. La quantificazione \ue8 stata espressa come Vibrio Abundance Index (VAI). Il VAI \ue8 stato definito come il rapporto tra il numero di Vibrio spp. e di batteri totali, entrambi quantificati mediante Real Time PCR, utilizzando primers rispettivamente genere specifici e universali. Entrambe le coppie di primers utilizzate generano ampliconi di piccole dimensioni (circa 100 pb) favorendo l\u2019amplificazione e riducendo l\u2019errore dovuto all\u2019et\ue0 del campione e alla formalina. I valori di abbondanza dei vibrioni cos\uec ottenuti sono stati messi in relazione alle variazioni della SST registrate durante lo stesso arco di tempo nei due siti studiati. Dall\u2019analisi dei risultati emerge un aumento dell\u2019 abbondanza relativa dei vibrioni correlato positivamente e in maniera statisticamente significativa con la temperatura superficiale dell\u2019acqua di mare nelle serie temporali dei campioni del Reno ma non in quelle dell\u2019Humber. Le differenze osservate tra i due siti potrebbero essere dovute alle diverse SST estive che raggiungono valori pi\uf9 elevati nel Reno rispetto all\u2019Humber. L\u2019aumento della concentrazione dei vibrioni registrato alla foce del Reno, coincide con una documentata serie di cambiamenti che hanno interessato tutti i livelli trofici, dal fitoplancton ai pesci, avvenuti alla fine degli anni \u201980 nel Mar del Nord, e che hanno portato ad un riscaldamento dell\u2019acqua di mare. Per studiare i cambiamenti avvenuti all\u2019interno della comunit\ue0 microbica associata ai campioni di CPR durante gli ultimi 40 anni, \ue8 stata applicata un\u2019 analisi di pyrosequencing su 5 campioni selezionati provenienti dalla foce del Reno (1961, 1972, 1976, 1998 e 2004). I risultati hanno mostrato come la frazione dei vibrioni associata agli organismi planctonici, incluso il patogeno umano V. cholerae, sia non solo aumentata in abbondanza ma anche in prevalenza rispetto alla comunit\ue0 microbica marina dal 1961 al 2004 nell\u2019area meridionale del Mare del Nord. Questi dati suggeriscono che l\u2019 aumento dei batteri appartenenti al genere Vibrio (sia patogeni che non patogeni) all\u2019interno della comunit\ue0 microbica marina associata al plancton in risposta al cambiamento climatico sia un evento che pu\uf2 interessare anche altre aree nel mondo. Mediante uno studio in situ di 8 mesi condotto nella laguna di Goro (Ferrara, Italia), l\u2019influenza della temperatura sull\u2019abbondanza dei vibrioni in ambiente acquatico \ue8 stata confermata a livello stagionale. I risultati ottenuti hanno mostrato come i vibrioni, sia in forma libera che adesi al plankton, raggiungano le pi\uf9 alte concentrazioni nei mesi estivi. Il ruolo della temperatura sull\u2019ecologia dei vibrioni patogeni \ue8 stato anche confermato mediante saggi volti a valutare gli effetti di questa variabiabile sull\u2019adesione di V. cholerae agli organismi planctonici. I risultati hanno mostrato come l\u2019efficienza di adesione di V. cholerae El Tor al copepode T. fulvus aumenti all\u2019aumentare della temperatura di incubazione, con un massimo registrato a 25\ub0C. Inoltre, per determinare se il gene che codifica per la GbpA (N-acetylglucosamine binding protein A), una delle principali adesine di V. cholerae coinvolte nell\u2019interazione con gli organismi planctonici, sia responsabile almeno in parte dell\u2019 aumento termo-dipendente dell\u2019efficienza di adesione, \ue8 stato valutato il livello di espressione del gene gbpA a diverse temperature. Dai risultati si evidenzia una aumento dell\u2019 espressione della GbpA all\u2019aumentare della temperatura, con la massima espressione registrata a 25\ub0C. In conclusione, con il presente lavoro \ue8 stato dimostrato: i) che i campioni formalinizzati del CPR possono essere utilizzati per lo studio della diversit\ue0 microbica fornendo la possibilit\ue0 di condurre studi retrospettivi sull\u2019ecologia delle comunit\ue0 microbiche marine; ii) che durante le ultime quattro decadi si \ue8 verificato un grosso cambiamento a livello della comunit\ue0 microbica associata al plankton nel sud del Mar del Nord in seguito all\u2019aumento della SST; iii) che la temperatura ha un ruolo fondamentale sulla persistenza dei vibrioni in ambiente acquatico, promuovendo la colonizzazione delle superfici planctoniche; iv) che l\u2019aumento della prevalenza dei batteri appartenenti al genere Vibrio, incluse le specie patogene, all\u2019interno della comunit\ue0 microbica associata al plancton, \ue8 un evento che pu\uf2 essere presente anche in altre aree come risposta al cambiamento climatico. Lo studio sui vibrioni in ambiente acquatico e sui meccanismi che ne regolano la diffusione e trasmissione all\u2019uomo sono di grande importanza per capire e conoscere l\u2019epidemiologia del colera e di altre malattie associate ad essi associate. La conoscenza di tali meccanismi rappresenta il punto di partenza per lo sviluppo di aggiornate misure di controllo basate su modelli predittivi.Vibrios are Gram negative marine bacteria and are still regarded by most marine microbiologists as the dominant culturable bacteria in the ocean. They can live in association with different biotic and abiotic substrates, in particular with chitinous plankton, which is considered one of the most abundant reservoir of these bacteria in the environment. Vibrio genus includes important human pathogens such as Vibrio cholerae, Vibrio parahaemolyticus and Vibrio vulnificus. There is substantial evidence that Vibrio-associated diseases are increasing worldwide with climate warming. Increased Sea Surface Temperature (SST) linked to El Ni\uf1o events have been shown to pre-date increases in cholera incidence in both Asia and South America. Similarly, climate anomalies have been implicated in the expansion of the geographical and seasonal range of seafood-borne illnesses caused by V. parahaemolyticus and V. vulnificus. Moreover, in recent years, an unexpected increase in the number of bathing infections associated with warm water Vibrio species has been reported in Northern Europe countries. Although much evidence has been accumulated on the long-term effects of ocean warming on eukaryotic populations, no experimental information exists for the effects this may have on marine prokaryotic abundance and diversity. An explanation for this gap is the lack of historical data at a global scale, being most available data collected on a seasonal scale and based on point samplings. The present work was designed to overcome this gap by applying a molecular analysis to formalin-fixed Continuous Plankton Recorder (CPR) samples, collected in the North Sea during the last 50 years. CPR is the longest running marine biological monitoring program in the world, operated by SAHFOS (UK) since 1954. CPR device is towed, at a depth of ~10 m, from ships during their normal sailings. Water passes through the CPR, and plankton is filtered onto a moving band of silk (270 \ub5m mesh size), covered by a second silk and spooled into a storage tank containing formalin. On the basis of the well established association between vibrios and plankton organisms, it is expected that CPR system significantly captures a major fraction of these bacteria providing a unique opportunity to carry out retrospective studies on Vibrio population dynamics. A set of 55 samples collected by the CPR survey in the North Sea from off the Rhine and Humber estuaries between 1961 and 2005 was analyzed. All the samples were collected in the month of August. DNA was extracted from each CPR samples, quantified and confirmed feasible for molecular analysis. Vibrios presence and relative abundance on CPR samples was assessed by applying a real-time PCR approach. The results were expressed as Vibrio Abundance Index (VAI) that was arbitrarily defined as the ratio of Vibrio spp. cells to the total number of bacterial cells assessed by real-time PCR using genus-specific and universal primers, respectively. Both the used couples of primers generate small and similar size amplicons (about 100 bp), allowing amplification to take place and avoiding age/formalin induced bias by assuming that DNA damage over time was the same for both amplified fragments. By plotting on a graph the obtained Vibrio abundance values with the SST data registered during the same period of time for each North Sea site under study, it was shown a long-term increase in relative Vibrio abundance coupled to a positive and statistically significant correlation with SST off the Rhine Estuary but not off the Humber Estuary during the past 44 years. Such different correlation results for the two areas may be related to the generally higher summer SST values recorded in the Rhine compared to the Humber area. The registered Vibrio abundance increase off the Rhine Estuary matches with the documented ecological regime shift occurred in the North Sea ecosystem in the late 1980s that affected all trophic levels, from phytoplankton to fish and that led to a warming of seawater in the southern North Sea. In order to study changes within microbial community associated to CPR samples over four decades, a pyrosequencing analyses was applied on five selected CPR samples collected off the Rhine Estuary in 1961, 1972, 1976, 1998 and 2004. The results provided evidence that bacteria belonging to the genus Vibrio, including V. cholerae, not only increased in relative abundance over the last half century in the southern North Sea, but also became dominant within the plankton-associated bacterial community of coastal marine waters. Based on this evidence, the increasing dominance of both harmless and pathogenic Vibrio spp. among the plankton - associated bacterial community of coastal marine water could be a likely event also in other areas around the world as a response to climate change. The role of temperature as a major environmental variable driving Vibrio spp. abundance has been confirmed at a local and seasonal scale. An in situ analysis, conducted during an 8 months cycle in the Goro Lagoon (Ferrara, Italy), showed that both free-living and plankton attached vibrios reached the highest concentrations during the warmest months. The role of temperature on the ecology of human pathogenic vibrios was further confirmed by another set of experiments intended to study in vitro temperature effects on V. cholerae adhesion to different plankton organisms. It was shown that the efficiency of colonization of the copepod T. fulvus by V. cholerae El Tor increases at increasing incubation temperatures, with a maximum efficiency registered at 25\ub0C. Another set of experiments was conducted in order to study if the observed temperature-dependent V. cholerae increase in interactions with plankton was due, at least in part, to an increase in the expression of the GbpA ligand, the main adhesin involved in V. cholerae interactions with plankton organisms by specifically binding N-acetyl glucosamine. GbpA gene expression level was evaluated relative to the expression of the endogenous control gene gyrA. The results showed that GbpA expression increases at increasing temperature values (from 15\ub0C to 25\ub0C). In conclusion, the presented findings have shown that: i) formalin preserved CPR samples can be used for the assessment of microbial diversity, opening up a novel window for long-term and retrospective studies of the global ecology of marine bacterial communities; ii) a major change in the structure of the bacterial community associated with plankton occurred in the southern North Sea in response to increasing SST over the last four decades; iii) SST plays a major role in affecting Vibrio spp. persistence in the aquatic environment also promoting colonization of plankton surfaces; this phenomenon is in turn dependent upon an enhanced expression of bacterial ligands mediating adhesion to chitin containing substrates; iv) based on all the above, the increasing dominance of marine Vibrio spp., including pathogenic species, among plankton-associated bacterial communities of coastal water, may have occurred (and may occur) in other areas around the world as a response to climate change. Studies on vibrios in natural aquatic environments and the mechanisms driving their spread and transmission to humans are of great importance for deciphering the epidemiology of cholera and other diseases (both food borne and extra-intestinal) associated to pathogenic vibrios. Knowledge in this field represents the starting point for the development of updated control measures based on predictive models that include biological, microbiological and physico-chemical variables

Thermoelectric Properties in Silver Chloride-Alkali Chloride Fused Mixtures

Abstract The initial thermoelectric power of the molten salt mixtures (Ag + Me)Cl (Me = Li, Na, Rb, Cs) has been measured at various temperatures around 800 °C using a silver electrode thermocell. In addition the thermoelectric power of molten pure AgCl is reported. These data have been used to obtain relative values of the heats of transport of the alkali cations in pure salts. Moreover the global behaviour of these mixtures in respect to an ideal model for the heat and electricity transport is discussed

Effects of global warming on Vibrio ecology

Vibrio-related infections are increasing worldwide both in humans and aquatic animals. Rise in global sea surface temperature (SST), which is approximately 1 \ub0C higher now than 140 years ago and is one of the primary physical impacts of global warming, has been linked to such increases. In this chapter, major known effects of increasing SST on the biology and ecology of vibrios are described. They include the effects on bacterial growth rate, both in the field and in laboratory, culturability, expression of pathogenicity traits, and interactions with aquatic organisms and abiotic surfaces. Special emphasis is given to the effect of ocean warming on Vibrio interactions with zooplankters, which represent one of the most important aquatic reservoirs for these bacteria. The reported findings highlight the biocomplexity of the interactions between vibrios and their natural environment in a climate change scenario, posing the need for interdisciplinary studies to properly understand the connection between ocean warming and persistence and spread of vibrios in sea waters and the epidemiology of the diseases they cause