Engineering a Novel Bivalent Oral Vaccine against Enteric Fever

Enteric fever is a major global healthcare issue caused largely by Salmonella enterica serovars Typhi and Paratyphi A. The objective of this study was to develop a novel, bivalent oral vaccine capable of protecting against both serovars. Our approach centred on genetically engineering the attenuated S. Typhi ZH9 strain, which has an excellent safety record in clinical trials, to introduce two S. Paratyphi A immunogenic elements: flagellin H:a and lipopolysaccharide (LPS) O:2. We first replaced the native S. Typhi fliC gene encoding flagellin with the highly homologous fliC gene from S. Paratyphi A using Xer-cise technology. Next, we replaced the S. Typhi rfbE gene encoding tyvelose epimerase with a spacer sequence to enable the sustained expression of O:2 LPS and prevent its conversion to O:9 through tyvelose epimerase activity. The resulting new strain, ZH9PA, incorporated these two genetic changes and exhibited comparable growth kinetics to the parental ZH9 strain. A formulation containing both ZH9 and ZH9PA strains together constitutes a new bivalent vaccine candidate that targets both S. Typhi and S. Paratyphi A antigens to address a major global healthcare gap for enteric fever prophylaxis. This vaccine is now being tested in a Phase I clinical trial ({"type":"clinical-trial","attrs":{"text":"NCT04349553","term_id":"NCT04349553"}}NCT04349553).     

Determination of Ascorbic Acid in Commercial Juices,on a Modified Carbon Paste Electrode,by Using a Taguchi Experimental Design

In this paper, a simple and rapid analytical method development for ascorbic acid determination by using differential pulse voltammetry method on copper(II)-phthalocyanine carbon paste electrode is shown. For this, several parameters, such as copper(II)-phthalocyanine (gram)/carbon (gram)/Nujol (millilitre) ratio, supporting electrolyte, pH and some others have been studied. In order to know the copper(II)-phthalocyanine influence on voltammetry peak height, a comparison between the analytical behaviour of a chemically modified carbon paste electrode and a conventional carbon paste electrode was carried out. The experimental conditions have been optimised by means of the experimental design using the Taguchi methodology. The catalytic oxidation peak current showed a linear depending on the ascorbic acid concentration in the range between 0.88 and 10.03 mg L⁻¹, with the detection limit of 0.55 mg L⁻¹. The proposed procedure was successfully applied to the determination of ascorbic acid in fruit juices without previous preparation and was compared with HPLC method applied at the same samples previously filtered.     

Determination of zinc,cadmium, lead and copper in pellets and pulp of sugar beet

Pulp is a residual product of the sugar industry resulting from the total extraction of sugar contained in the root of sugar beet and is normally used in the form of pulp or pellets as food in the cattle industry. The objective of this work was the simultaneous determination of zinc, cadmium, lead and copper in pellets and dried pulp. For this we have developed a method of analysis using anodic stripping voltammetry in the differential pulse mode (DPASV) at a hanging mercury drop electrode (HMDE) and compared the results with those obtained by means of electrothermal atomic absorption spectrometry (ETAAS). We conclude that DPASV can be used as an alternative method to ETAAS to determine low concentrations of Zn, Cd, Cu and Pb in such samples, having the advantage of allowing the determination of all four metals simultaneously. From the analysis of real samples it can be concluded that Zn is present in the highest concentration, ranging from 3 to 30 mg kg^?1, while Cd, Pb and Cu concentrations were always lower than 1, 8 and 8 mg kg^?1 respectively. Copyright © 2005 Society of Chemical Industry     

Effects of selected trace elements on plant growth

Trace elements in plants are of general concern because of their importance in both animal nutrition and plant growth. Consequently, these elements are the most extensively studied in plants and foodstuffs. We surveyed those other elements which have been shown to have some beneficial effects on the growth of a few plant species only, and, although evidence for this essentiality continues to accumulate, their conclusive essentiality for higher plants still needs confirmation. Plants use these trace elements in small quantities, and we include the following in our review: titanium, vanadium, cobalt, nickel, aluminium, silicon, arsenic, selenium, fluorine and iodine. Their effects on plant growth are evaluated, covering the following: absorption, transport and accumulation, biochemical functions, deficiency and toxicity.     

Total and extractable contents of trace metals in agricultural soils of the Valderas area, Spain

The surface horizons of four agricultural field soils (Mollic ustifluvents, Alfic Xerochrepts, Typic Palexeralfs, Typic Haploxeralfs) were sampled to determine the total copper, cobalt, molybdenum, zinc, chromium, nickel, selenium, cadmium, lead, mercury, lithium and strontium, and were also fractionated by an extraction procedure to estimate the quantities of these trace metals in soluble form. The extractants used were the following: 1.0 N NH4 OAc for lithium and strontium, 0.05 M Na2-EDTA for cadmium, copper, nickel and zinc, 2.5% (w/v) acetic acid for lead, 2.5% (w/v) acetic acid and 2% (w/v) dithizone for cobalt, 2% (w/v) diethyldithiocarbamate solution for selenium, 0.1 NHCl for chromium, and 0.5 NHCl for mercury. The total content of these twelve elements in the four field soils sampled were lower than the levels quoted in the literature, although for different geochemical systems. The percentage of the total element content in soluble form was (except for selenium) generally very low, averaging between 5.5 and 8% for copper, 1.6 and 2.5% for cobalt, 8 and 10% for molybdenum, 1.8 and 2.2% for zinc, 14.2 and 17.7% for chromium, 5.5 and 6.4% for nickel, 30 and 55% for selenium, 8 and 14% for cadmium, 3 and 3.6% for lead, 8.3 and 11% for mercury, 5 and 7% for lithium, and 4.4 and 5.7% for strontium, regardless of the soil type.     

Natural radiation doses to the population in a granitic region in Spain

The global average effective dose from natural radiation sources is estimated to be 2.4 mSv y(-1). Nevertheless, local variations in the radiation exposure may differ by orders of magnitude. In this paper, we study a rural area in western Salamanca (Spain) where doses are potentially well above the stated average value. Its geology consists mostly of granite and schist, presenting various uranium mineralisations, some of which were exploited in former years. Water samples, both surface and groundwater, were collected in selected villages and measured by liquid-scintillation spectrometry. 222Rn in dwellings was determined in dwellings by means of short-term measurements, using Picorad vials and long-term measurements with CR-39 detectors. The committed effective doses to the inhabitants due to indoor 222Rn and 222Rn and 226Ra in drinking water were assessed using the dose conversion factors proposed in the UNSCEAR 2000 report.