Toluene-induced oxidative stress in several brain regions and other organs

The in vivo dose-response relationship between toluene and reactive oxygen species (ROS) formation in rat brain, liver, kidney, and lung, and the time-course of these effects has been characterized. The rate of oxygen radical formation was measured using the probe 2',7'-dichlorofluorescin diacetate. In vivo exposure to various doses of toluene (0.5, 1.0, and 1.5 g/kg ip) elicited a dose-dependent elevation of ROS generation within crude mitochondrial fractions obtained from rat lung and kidney, and within crude synaptosomal fractions from cerebellum. ROS formation in crude mitochondrial fractions from liver, and crude synaptosomal fractions from striatum and hippocampus, reached a maximum value at relatively low doses of toluene. Of the brain regions, the hippocampus had the highest induced levels of ROS. In vivo exposure to a single dose of toluene (1.5 g/kg ip), revealed that toluene-induced ROS reached a peak within 2 h, which correlated directly with measured toluene blood levels. This elevated oxidative activity was maintained throughout the next 24 h, even though blood values of toluene decreased to negligible amounts. These results demonstrate that exposure to toluene results in broad systemic elevation in the normal rate of oxygen radical generation, with such effects persisting in the tissues despite a rapid decline in toluene blood levels. Acute exposure to toluene may lead to extended ROS-related changes, and this may account for some of the clinical observations made in chronic toluene abusers.     

On-column Refolding of Diphtheria Toxin Variant CRM197 by Different Metal-Chelating Affinity Chromatography Matrices

We have previously shown that the diphtheria toxin variant CRM 197 （cross-reacting material 197） can be overexpressed in Escherichia coli at high levels, yielding insoluble aggregates, which were solubilized using urea. This study reports a comparison of three matrices suitable for the purification and refolding of recombinant CRM197 by metal-chelating affinity chromatography, Moreover, we show that refolded CRM197 features enzymatic activity.     

Luminescent enzymatic flow sensor for d- and l-lactate assay in beer

 A bioluminescent flow sensor, previously developed for the determination of both d- and l-lactate in clinical samples, was utilized to carry out the same assay in beer. The sensor monitored the reduced form of nicotinamide adenine dinucleotide, produced by nylon-immobilized d- and l-lactate dehydrogenase, by means of bacterial bioluminescent enzymes immobilized on a separate nylon coil. The preparation of beer samples was very simple as only a modification of pH and a dilution were necessary. The recoveries ranged from 91% to 104%, and the relative standard deviations at the 1 mmol 1^–1 level were 4.6% and 6.7% for l- and d-lactate respectively. The response was linear in the range 0.1–10 mmol 1^–1 for both d- and l-lactate. The total amount of lactate determined by bioluminescent biosensor (x) and by HPLC (y) showed a very good correlation (y=0.654 x+88.1, n=29, r=0.918). The flow injection system developed allowed the determination of not only the total but also the individual contents of d- and l-lactate in beer, and the timely discovery of the unwanted presence of lactic acid bacteria. Received: 14 January 1999 / Revised version: 29 April 1999     

Effect of Fermentation and Drying on Procyanidins, Antiradical Activity and Reducing Properties of Cocoa Beans

This work was aimed to determine the effect of fermentation and drying on the content and profile of procyanidins (from monomers P1 to polymers P10) as well as on the antiradical and scavenging properties of cocoa beans. To this purpose, three experiments were carried out: a traditional fermentation process followed by air drying and two pilot-scale fermentation processes by either natural microbiota or starter followed by sun drying. Procyanidins were evaluated by HPLC analysis, while the total polyphenol index (TPI), the antiradical activity as well as the reducing power were determined by means of the reaction with the Folin–Ciocalteu reagent, the decolorization assays of the ABTS radical (TEAC) and the Ferric Reducing Antioxidant Power (FRAP) methods, respectively. Both the traditional and pilot-scale processes resulted to affect the profile and content of the procyanidins fractions as well as the antiradical and reducing power functionality. Drying caused a severe reduction of compounds and thus resulted to be the critical step for the loss of procyanidins and monomers in particular. The indices of functionality generally showed a decreasing trend as a consequence of processing, and their evolution was similar to that observed in procyanidins content. To study the relationship between the individual procyanidins and the antioxidant activity expressed as TEAC, FRAP and TPI, the data set were processed by modified partial least squares regression. The obtained models presented a good predictive ability. Normalised regression coefficients showed that the relative contribution of each single class of compounds to total antioxidant activity resulted as follows: P1?>?P2?>?P3?>?P4?>?P6?>?P8?>?P5?>?P7?>?P9?>>?P10.     

Contribution of enterococci to the spread of antibiotic resistance in the production chain of swine meat commodities

Thirty-six samples, including fecal specimens, dry feedstuffs, raw and processed pork meat products, and dry fermented sausages, were collected from two production chains of swine meat commodities and analyzed for the presence of 11 antibiotic resistance (AR) genes. Specific PCR assays carried out on DNA extracted directly from the samples revealed a high incidence of the genes tet(K) (80.5%), ermB (66.7%), and tet(M) (66.7%). Feces and feedstuffs gave the largest number of positive amplifications. To elucidate the contribution of enterococci to the occurrence and spread of AR, 146 resistant enterococci were isolated, and their identity, genetic fingerprints, and AR gene profiles were determined by means of molecular techniques. Enterococcus faecalis and Enterococcus faecium were the predominant isolated species (43.8 and 38.4%, respectively); Other Enterococcus species identified were E. durans (8.9%), E. hirae (2.7%), E. gallinarum (2.1%), E. mundtii (2.1%), and E. casseliflavus (2.1%). A number of isolates displayed a complex AR gene profile comprising up to four different resistance determinants. The genes tet(M) and ermB were highly diffused, being present in 86.9 and 84.9%, respectively, of the isolates. The application of amplified fragment length polymorphism fingerprinting was particularly valuable to monitor the resistant enterococcal isolates along the production chain and to individuate steps in which contamination might occur. In fact, isolates of E. faecalis and E. faecium showing the same amplified fragment length polymorphism profile and AR gene pattern were detected in samples taken at different steps of the food chain suggesting three cases of bacterial clonal spread.     

Global-Mean Temperature Change from Shipping toward 2050: Improved Representation of the Indirect Aerosol Effect in Simple Climate Models

We utilize a range of emission scenarios for shipping to determine the induced global-mean radiative forcing and temperature change. Ship emission scenarios consistent with the new regulations on nitrogen oxides (NO(x)) and sulfur dioxide (SO(2)) from the International Maritime Organization and two of the Representative Concentration Pathways are used as input to a simple climate model (SCM). Based on a complex aerosol-climate model we develop and test new parametrizations of the indirect aerosol effect (IAE) in the SCM that account for nonlinearities in radiative forcing of ship-induced IAE. We find that shipping causes a net global cooling impact throughout the period 1900-2050 across all parametrizations and scenarios. However, calculated total net global-mean temperature change in 2050 ranges from -0.03[-0.07,-0.002]°C to -0.3[-0.6,-0.2]°C in the A1B scenario. This wide range across parametrizations emphasizes the importance of properly representing the IAE in SCMs and to reflect the uncertainties from complex global models. Furthermore, our calculations show that the future ship-induced temperature response is likely a continued cooling if SO(2) and NO(x) emissions continue to increase due to a strong increase in activity, despite current emission regulations. However, such cooling does not negate the need for continued efforts to reduce CO(2) emissions, since residual warming from CO(2) is long-lived.     

Technical note: Fourier transform infrared spectral analysis in tandem with 31P nuclear magnetic resonance spectroscopy elaborates detailed insights into phosphate partitioning during skimmed milk microfiltration and diafiltration

Our previous study identified peaks in the ³¹P nuclear magnetic resonance (³¹P NMR) spectra of skim milk, denoting the interaction of different phosphate species such as inorganic and casein-associated phosphate during the separation of colloidal and serum phases of skim milk by microfiltration (MF) and diafiltration (DF). In the current study, we investigated the same samples generated by the aforementioned separation using attenuated total reflectance (ATR) Fourier transform infrared (FTIR) spectroscopy analysis. The results confirmed that the technique was not only capable of differentiating between the mineral equilibrium of the casein phosphate nanocluster (CPN) and milk serum, but also complemented the application of ³¹P NMR. An ATR-FTIR broad band in the region of 1,055 to 1,036 cm^?1 and a specific band at 1,076 cm^?1 were identified as sensitive to the repartitioning of different phosphate species in milk in accordance with the ³¹P NMR signals representing casein-associated phosphate and inorganic phosphate in the serum. A third ATR-FTIR signal at 1,034 cm^?1 in milk, representing precipitated inorganic calcium phosphate, had not previously been detected by ³¹P NMR. Thus, the results indicate that a combination of ATR-FTIR and ³¹P NMR spectroscopies may be optimally used to follow mineral and protein phase changes in milk during membrane processing.     

Application of a radical scavenging activity test to measure the total antioxidant activity of poultry meat

The antioxidant activity of the hydrophilic and lipophilic fraction of poultry meat was determined in terms of ‘radical scavenging activity’ (RSA) using a modified ABTS radical cation decolorization method.The method uses the extraction of hydrophilic and lipophilic fractions in water and methanol–chloroform, respectively. The determination of the RSA of the lipophilic fraction was conducted using a chloroform extract and maintaining a constant chloroform:ethanol ratio in the solution of analysis. The method was tested on nine samples of poultry breasts and thigh meats and permitted to quantify the RSA in terms of μmol Trolox equivalent antioxidant capacity (TEAC) with a mean relative standard deviation of less than 5%.The contribution of the hydrophilic fraction to the total RSA was much higher than that of the lipid soluble fraction. Breast showed a higher RSA than thigh meat due to its lower total lipids content. The total RSA value (TEAC = 2.4 μmol g⁻¹) suggests that poultry meat could significantly contribute to the antioxidant activity of the diet.     

Application of Central Composite Design to evaluate the antilisterial activity of hydro-alcohol berry extract of Myrtus communis L.

The antimicrobial activity of the hydro-alcohol extract of Myrtus communis L. (ME) berries was investigated against six Listeria monocytogenes strains (2 type strains and 4 isolates). Sub-lethal ME concentrations reduced L. monocytogenes counts by at least 2 log cycles. A Central Composite Design was used to investigate the combined effects of sub-lethal concentrations of ME (0.039–0.195 mL/100 mL), NaCl (0–2.0 g/100 mL) and pH (5.0–7.0) on strains growth. ME affected growth parameters, generally extending lag phase length and reducing maximum growth, sometimes with interactive effects with pH. The highest ME concentrations (0.117–0.195 mL/100 mL) combined with the lowest pH values (5.0–6.0) strongly reduced or even inhibited strains growth.     

Measuring Data Management Practice Maturity: A Community's Self-Assessment

As increasing amounts of data flow within and between organizations, the problems that can result from poor data management practices are becoming more apparent. Studies have shown that such poor practices are widespread. All organizations have data architectures, whether explicitly documented or implicitly assumed. An important data management process is to document the architecture's capabilities, making it more useful to the organization. Increasing data management practice maturity levels can positively impact the coordination of data flow among organizations, individuals, and systems. Results from a self-assessment provide a roadmap for improving organizational data management practices