Eco-physiological and Antioxidant Responses of Holm Oak (<Emphasis Type="Italic">Quercus ilex</Emphasis> L.) Leaves to Cd and Pb

Plants of the urban environment are exposed to a wide range of pollutants, including heavy metals. This research studies in situ the eco-physiological and antioxidant responses of holm oak (Q. ilex) leaves to Pb and Cd to assess the mechanisms of metal tolerance in this species, widely used as biomonitor. Leaves of plants grown at parks and roadsides were analyzed for photosynthetic activity, Pb and Cd concentration in tissues and cell-free extracts, thiol groups, D1 and Rubisco protein content, ascorbic acid (AsA) amount, and catalase (CAT) activity. The main results evidenced that Cd concentration was higher in leaves collected at the park out from the downtown; whereas Pb was most abundant in leaves sampled at the roadside nearby the highway. Pb in cell-free extracts was higher in park than in roadside leaves. Although Cd in the leaf tissues was twofold lower than Pb, it was more abundant than Pb in cellular extracts deprived of all particulate matter. Leaves responded to different concentration of Cd and Pb modulating some eco-physiological and biochemical traits, roadside leaves showed reduced leaf lamina, higher content of photosynthetic pigments, hydrogen peroxide, and AsA, as well as higher CAT activity compared to park leaves. In the roadside leaves, a stress condition for photosynthetic apparatus can be hypothesized on the basis of the decline of photochemical activity, the increase of NPQ, and the reduction of Rubisco and D1 protein content. The elevated presence of thiol groups in these leaves suggests a possible role of Pb and Cd in activation of antioxidant responses.     

Biotechnological production of vitamin B2-enriched bread and pasta

Lactic acid bacteria (LAB) were obtained from durum wheat flour samples and screened for roseoflavin-resistant variants to isolate natural riboflavin-overproducing strains. Two riboflavin-overproducing strains of Lactobacillus plantarum isolated as described above were used for the preparation of bread (by means of sourdough fermentation) and pasta (using a prefermentation step) to enhance their vitamin B2 content. Pasta was produced from a monovarietal semolina obtained from the durum wheat cultivar PR22D89 and, for experimental purposes, from a commercial remilled semolina. Several samples were collected during the pasta-making process (dough, extruded, dried, and cooked pasta) and tested for their riboflavin content by a high-performance liquid chromatography method. The applied approaches resulted in a considerable increase of vitamin B2 content (about 2- and 3-fold increases in pasta and bread, respectively), thus representing a convenient and efficient food-grade biotechnological application for the production of vitamin B2-enriched bread and pasta. This methodology may be extended to a wide range of cereal-based foods, feed, and beverages. Additionally, this work exemplifies the production of a functional food by a novel biotechnological exploitation of LAB in pasta-making.     

Fluorescence properties of humic acid interaction products with s-triazine and bipyridilium herbicides and their Cu complexes: a multivariate approach

Purpose

Excitation–emission matrices spectroscopy (EEMS) of soil humic acids (HAs) contains large amount of information on their properties, as well as on the dynamics related to their intra- and inter-molecular interactions. The objective of this research was (i) to show that EEMS represents a useful tool to investigate the molecular and mechanistic aspects of HA adsorbing capacity towards atrazine (A) and paraquat (P) with or without Cu²⁺ ions and (ii) to evaluate if additional information on these mechanisms can be obtained by combining EEMS with principal component analysis (PCA).

Materials and methods

HAs have been isolated from soil samples collected in a citrus field at three locations, within the plant rows (HAa); between the rows (HAb) and in a adjacent, control soil (HAc). Interaction products were obtained between each HA and A and P, with or without Cu ions. Elemental analysis and Fourier-transorm Infrared Spectroscopy were applied to support fluorescence data. Fluorescence spectra were recorded on aqueous solutions, and fluorescence intensity (FI) values were normalized using a quinine sulphate standard. PCA analysis was performed using the software STATGRAPHICS Centurion XV.I.

Results and discussion

The EEM spectra of the three unreacted HAs are characterized by the presence of two fluorophores α and β, in the region of longer wavelengths pairs (EEWP). The EEM spectra of the HA-A interaction products are featured by the same two fluorophores, with FI values decreased of about 50%, whereas those of the HA-P interaction products show a unique peak, γ, at intermediate EEWP. Finally, the EEM spectra of HA-A-Cu²⁺ show, with respect to HA-A samples, a blue shift of the α peak with an additional decrease of FI values (about 60%) and the disappearance of the peaks β, whereas those of HA-P-Cu²⁺ feature, in comparison with those of HA-P, a small red-shift of the peak γ. PCA data suggest that Cu ions do not affect the interaction mechanism between HA and P, whereas it appears to exercise a strong influence on interaction between HA and A.

Conclusions

The results obtained indicate that EEMS allows direct measurements of the adsorbing capacity of HA towards atrazine and paraquat. Additional information obtained by PCA analysis show that Cu ions behave like a good antagonist in preventing the formation of ionic bonds between HA and atrazine, whereas Cu is not able to affect the prevalent mechanism of HA interaction with paraquat, which is a charge-transfer bond.

     

Application of Novel Fulvic Acid-Coated Magnetite Nanoparticles for CO<Subscript>2</Subscript><Superscript>−</Superscript>-Mediated Photoreduction of Cr(VI)

We here isolate fulvic acids from vermicompost to prepare and characterize novel fulvic acid-coated magnetite nanoparticles. UV-A irradiation of suspensions of the nanoparticles under different experimental conditions led to photo-reduction of Cr(VI). In anoxic conditions in the presence of formic acid, after 60 min of irradiation ca. 100% of Cr(VI) was reduced. Under these conditions, the carbon dioxide radical anions, CO₂ ^.- , mediated the photo-reduction of Cr(VI). However, the high reduction potential of Cr(VI) and the variety of reactive species generated upon UV-A irradiation make this nanomaterial also suitable for Cr(VI) photo-reduction also under aerobic conditions in the presence of formic acid or under anoxic conditions without the addition of formic acid. The possible photodegradation routes involved are discussed in detail.     

Synthesis of antioxidants in wheat sprouts

Aqueous and ethanolic extracts from wheat (Triticum aestivum) sprout powder were analyzed to determine its reduction and antioxidant activities. Mean and standard deviation of five independent samples were reported. The results showed that the micromoles of potassium ferricyanide reduced by aqueous and ethanolic extracts corresponding to 1 g of sprout powder (80.6 +/- 11.2 and 9.7 +/- 1.8, respectively) were higher than that reduced by 1 mg of other reducing compounds: ascorbic acid, rutin, quercetin, and reduced gluthatione (4.8 +/- 0.7, 3.8 +/- 1.2, 4.8 +/- 1.7, and 1.6 +/- 0.4, respectively). In addition, the oxygen superoxide scavenging activity performed by sprout extracts (from 1 g of powder) is comparable to that shown by 10 mg of antioxidant pure compounds (rutin and quercetin). Biochemical analysis of the sprout extracts shows that the antioxidant activity is mainly due to reducing glycoside and polyphenolic compounds.     

Prevalence of Giardia and Cryptosporidium species in dog park attending dogs compared to non-dog park attending dogs in one region of Colorado

Dog parks are very popular in urban areas, but there are no current studies attempting to correlate visits to dog parks and risk of colonization by enteric parasites. The purpose of this study was to determine whether dog park visitation is associated with an increased prevalence of enteric parasites or an increase in prevalence of gastrointestinal signs in dogs in northern Colorado. Feces from dogs owned by veterinary students or Veterinary Teaching Hospital staff members were submitted with a completed survey form detailing dog park attendance rates, fecal character scores, and other clinical information. Feces were examined microscopically for parasites after sugar centrifugation, for Giardia spp. cysts and Cryptosporidium spp. oocysts by a commercially available immunofluorescence assay (FA) and the FA positive samples were genotyped after PCR amplification. The Giardia assemblages were determined using the glutamate dehydrogenase (GDH) β-giardin and triose phosphate isomerase (TPI) genes and the Cryptosporidium species were determined using the heat shock protein-70 gene. A total of 129 fecal samples were assayed; 66 were from dog park attending dogs and 63 were from non-dog park-attending dogs. The overall parasite prevalence rate was 7.0% (9 of 129 samples). Dog park attending dogs were more likely to be positive for Giardia or Cryptosporidium than non-dog park-attending dogs (p=0.0279), but there was no association of gastrointestinal signs with dog park attendance or with fecal flotation or FA results. The five Giardia isolates were assemblage C and/or D and the one Cryptosporidium isolate was Ctenocephalides canis.     

Rheological properties and sugar composition of locust bean gum from different carob varieties (Ceratonia siliqua L.)

The seeds of the main Italian carob varieties, Latinissima and Tantillo, and those of two selected accessions of Latinissima were evaluated in terms of yield, rheological properties, and sugar composition of the endosperm (LBG). The separation of the seed components in Latinissima and its seedlings yielded meanly 52.2% gum, 17.4% germ, and 30.5% tegument, whereas Tantillo furnished a lower gum yield (38.5%) and a higher yield of tegument (45.8%). The viscosity of 1% LBG aqueous solutions was measured at different shear rates (3-60 rpm), pH values (3.0-6.0), and temperatures (10-60 degrees C). The best results were shown by Latinissima, whereas Tantillo provided always the poorest thickening capacity. The content of free simple sugars and sucrose in the raw flours, the total monosaccharide residues after acidic hydrolysis, the mannose/galactose ratio, and the distribution of polysaccharides by size exclusion chromatography accounted for the observed viscosities. The seeds of Latinissima showed the highest technological potential.