Hake slices stored in retail packages under modified atmospheres with CO<Subscript>2</Subscript>- and O<Subscript>2</Subscript>-enriched gas mixes

This paper presents the examination of the evolution of biochemical, sensory and microbiological changes occurring in hake slices stored in modified atmospheres containing three gas mixes. It also shows how these changes relate to changes in the concentrations of the gas mixes in the tray packs during storage. At the outset of storage, there was a pronounced drop in the level of CO₂, associated with lowering of the pH and lower scores for texture in sensory inspection. Nevertheless, by the end of storage, CO₂ concentrations had increased. This was associated with growth of Enterobacteriaceae and with more pronounced decreases of O₂, which is consumed by these microorganisms. Weight loss was greater in the atmosphere-stored lots, possibly due to the action of CO₂. TMA-N and TVB-N began to increase on days 10 and 13 of storage and reached the permitted limits on days 17 and 20. Our analyses revealed no appreciable differences of performance between the different gas mixes, possibly because the gas levels were very similar in the various lots throughout storage.     

Functional and proliferative effects of repeated low‐dose oral administration of furan in rat liver

Scope: Furan, a food contaminant formed during heat processing, induces hepatocellular tumors in rodents and high incidences of cholangiocarcinomas in rats even at the lowest dose (2 mg/kg b.w.) administered. Initial estimates suggested that human intake of furan may be as high as 3.5 μg/kg b.w./day, indicating a relatively narrow margin of exposure. The aim of this study was to establish dose–response data for cytotoxicity, regenerative cell proliferation and secondary oxidative DNA damage in livers of male F344 rats treated with furan at doses ≤2 mg/kg b.w. for 28 days. Methods and results: No significant signs of hepatotoxicity other than a mild, dose‐dependent increase in serum cholesterol and unconjugated bile acids, and no evidence of oxidative DNA damage were seen. Histopathological alterations and proliferative changes were restricted to subcapsular areas of the left and caudate liver lobes. Conclusion: Although statistically significant effects were only seen at the 2 mg/kg b.w. dose during the course of our study, a ～two and ～threefold increase in 5‐bromo‐2′‐deoxyuridine labeling index was observed at 0.1 and 0.5 mg/kg b.w., respectively, suggesting that chronic exposure to doses even below 2 mg/kg b.w. may cause proliferative changes in rat liver and highlighting the need to assess furan carcinogenicity at lower doses.     

Antibiotic susceptibility of members of the Lactobacillus acidophilus group using broth microdilution and molecular identification of their resistance determinants

The range of antibiotic susceptibility to 13 antibiotics in 101 strains of the Lactobacillus acidophilus group was examined using the lactic acid bacteria susceptibility test medium (LSM) and broth microdilution. Additionally, microarray analysis and PCR were applied to identify resistance genes responsible for the displayed resistant phenotypes in a selection of strains. In general, narrow as well as broad unimodal and bimodal MIC distributions were observed for the Lactobacillus acidophilus group and the tested antimicrobial agents. Atypically resistant strains could be determined by visual inspection of the obtained MIC ranges for ampicillin, chloramphenicol, clindamycin, erythromycin, quinupristin/dalfopristin, streptomycin and tetracycline. For most of these atypically resistant strains underlying resistance determinants were found. To our knowledge erm(A) was detected in lactobacilli for the first time within this study. Data derived from this study can be used as a basis for reviewing present microbiological breakpoints for categorization of susceptible and resistant strains within the Lactobacillus acidophilus group to assess the safety of microorganisms intended for use in food and feed applications.     

In vitro bio-accessibility and antioxidant activity of grape polyphenols

The bio-accessibility (the release of compounds from solid food matrices) of grape polyphenols using an in vitro model simulating gastro-intestinal conditions has been investigated. In vitro studies are needed to unravel factors affecting the release of antioxidants during digestion. The amount of bio-accessible polyphenols, flavonoids and anthocyanins increases during gastric digestion. The transition in the intestinal environment causes a decrease in all the analyzed classes of polyphenols followed by a renewal in the extraction of polyphenols and flavonoids but not of anthocyanins. The stability under gastro-intestinal conditions of pure phenolic acids, flavonoids and resveratrol has been analysed. Gastric digestion had no effect on any phenolic tested. Phenolic acids and resveratrol were degraded under pancreatic conditions whereas catechin and quercetin were not. Changes in antioxidant activity during digestion were correlated to the changes in polyphenols concentration as well as to the pH. Our results suggest that the gastro-intestinal tract may act as an extractor where polyphenols are progressively released from solid matrix and made available for the absorption or to exert their biological effects in the gastro-intestinal tract.     

Case-control study of toenail cadmium and prostate cancer risk in Italy

A role of cadmium exposure in prostate cancer etiology has been suggested by epidemiologic and laboratory studies, but conclusive evidence on this topic is still lacking. We investigated the relation between cadmium exposure, estimated by determining toenails cadmium levels, and prostate cancer risk in forty patients newly diagnosed with prostate cancer and fifty-eight hospital controls recruited in two provinces from southern and northern Italy. We found an excess cancer risk in subjects in the third and fourth (highest) quartiles of toenail cadmium concentration (odds ratio 1.3 and 4.7, respectively) compared with subjects in the bottom quartile. Results were basically unchanged when limiting the analysis to each province or entering toenail cadmium concentrations as continuous values in the regression model (P=0.004). Despite the limited statistical stability of the point estimates, these findings appear to support the hypothesis that cadmium exposure increases prostate cancer risk.     

Dispersion controlled highly nonlinear fibers for all-optical processing at telecoms wavelengths

We review our recent progress in the development of lead silicate glass fibers with high nonlinearity and tailored near-zero dispersion at telecommunication wavelengths, encompassing holey, all-solid microstructured and W-type fiber designs. The fabrication techniques and relative merits of each fiber design are described in detail. The optical properties of the fabricated fibers are assessed both experimentally and through accurate numerical simulations. The significant potential of lead silicate highly nonlinear fibers for all-optical signal processing at telecommunication wavelengths is shown via a number of key experimental demonstrators.     

Removal of virus to protozoan sized particles in point-of-use ceramic water filters

The particle removal performance of point-of-use ceramic water filters (CWFs) was characterized in the size range of 0.02-100 μm using carboxylate-coated polystyrene fluorescent microspheres, natural particles and clay. Particles were spiked into dechlorinated tap water, and three successive water batches treated in each of six different CWFs. Particle removal generally increased with increasing size. The removal of virus-sized 0.02 and 0.1 μm spheres were highly variable between the six filters, ranging from 63 to 99.6%. For the 0.5 μm spheres removal was less variable and in the range of 95.1-99.6%, while for the 1, 2, 4.5, and 10 μm spheres removal was >99.6%. Recoating four of the CWFs with colloidal silver solution improved removal of the 0.02 μm spheres, but had no significant effects on the other particle sizes. Log removals of 1.8-3.2 were found for natural turbidity and spiked kaolin clay particles; however, particles as large as 95 μm were detected in filtered water.     

Effects of low-level exposure to xenobiotics present in paints on oxidative stress in workers

Paints are composed of an extensive variety of hazardous substances, such as organic solvents and heavy metals. Biomonitoring is an essential tool for assessing the risk to occupational health. Thus, this study analyzed the levels of biomarkers of exposure for toluene, xylene, styrene, ethylbenzene, and lead, as well as the oxidative stress biomarker alterations in painters of an industry. Lipid peroxidation biomarker (MDA), δ-aminolevulinate dehydratase (ALA-D), nonprotein thyol groups, superoxide dismutase and catalase (CAT) were analyzed in exposed and nonexposed subjects. We estimated which of the paint constituents have the greatest influence on the changes in the biomarkers of oxidative stress in this case of co-exposure. The results demonstrated that despite the fact that all the biomarkers of exposure were below the biological exposure limits, the MDA levels and antioxidant enzyme activities were increased, while nonprotein thyol groups and ALA-D levels were decreased in painters when compared with nonexposed subjects. After statistic test, toluene could be suggested as the principal factor responsible for increased lipid peroxidation and inhibition of ALA-D enzyme; however, further studies on the inhibition of ALA-D enzyme by toluene are necessary.     

Atrazine degradation and enzyme activities in an agricultural soil under two tillage systems

The content of atrazine and its metabolites (hydroxyatrazine, deethylatrazine and deisopropylatrazine) as well as the activities of two soil enzymes (urease and beta-glucosidase) were evaluated in an acid agricultural soil, located in a temperate humid zone (Galicia, NW Spain), with an annual ryegrass-maize rotation under conventional tillage (CT) and no tillage (NT). Samples were collected during two consecutive years from the arable layer at two depths (0-5 cm and 5-20 cm) and different times after atrazine application. Hydroxyatrazine and deisopropylatrazine were the main metabolites resulting from atrazine degradation in the acid soil studied, the highest levels being detected in the surface layer of the NT treatment. A residual effect of atrazine was observed since hydroxyatrazine was detected in the arable layer (0-5 cm, 5-20 cm) even one year after the herbicide application. Soil enzyme activities in the upper 5 cm layer under NT were consistently higher than those in the same layer under CT. Urease and beta-glucosidase activities decreased with depth in the profile under NT but they did not show any differences between the two depths for the plots under CT. For both tillage systems enzyme activities also reflected temporal changes during the maize cultivation; however, no consistent effect of the herbicide application was observed.     

Design and Characterization of a Peptide Mimotope of the HIV-1 gp120 Bridging Sheet

The Bridging Sheet domain of HIV-1 gp120 is highly conserved among the HIV-1 strains and allows HIV-1 binding to host cells via the HIV-1 coreceptors. Further, the bridging sheet domain is a major target to neutralize HIV-1 infection. We rationally designed four linear peptide epitopes that mimic the three-dimensional structure of bridging sheet by using molecular modeling. Chemically synthesized peptides BS3 and BS4 showed a fair degree of antigenicity when tested in ELISA with IgG purified from HIV(+) broadly neutralizing sera while the production of synthetic peptides BS1 and BS2 failed due to their high degree of hydrophobicity. To overcome this limitation, we linked all four BS peptides to the COOH-terminus of GST protein to test both their antigenicity and immunogenicity. Only the BS1 peptide showed good antigenicity; however, no envelope specific antibodies were elicited upon mice immunization. Therefore we performed further analyses by linking BS1 peptide to the NH2-terminus of the E2 scaffold from the Geobacillus Stearothermophylus PDH complex. The E2-BS1 fusion peptide showed good antigenic results, however only one immunized rabbit elicited good antibody titers towards both the monomeric and oligomeric viral envelope glycoprotein (Env). In addition, moderate neutralizing antibodies response was elicited against two HIV-1 clade B and one clade C primary isolates. These preliminary data validate the peptide mimotope approach as a promising tool to obtain an effective HIV-1 vaccine.