Effects of glyphosate on rhizosphere soil microbial communities under two different plant compositions by cultivation-dependent and -independent methodologies

We studied, under two different plant compositions, the short-term effects of glyphosate on rhizosphere soil microbial communities through the utilization of cultivation-dependent and -independent techniques. A short-term pot study was carried out using factorial treatments that included two different compositions of forage plant species (triticale versus a mixture of triticale and pea) and two concentrations of glyphosate (50 and 500 mg active ingredient kg⁻¹ soil, as a commercial formulation, Roundup Plus) arranged in a completely randomized design experiment with four replicates. Control plants (no glyphosate added) were clipped in an attempt to compare two methods of weed control (manual = clipping; chemical = herbicide treatment). Rhizosphere soil was sampled 15 and 30 days after glyphosate treatment and the following soil components were determined: potentially mineralizable nitrogen, ammonium content, community-level physiological profiles using Biolog Ecoplates™, DNA microbial biomass and genotype diversity by means of PCR-DGGE. Fifteen days after herbicide treatment, a glyphosate-induced stimulation of the activity and functional diversity of the cultivable portion of the heterotrophic soil microbial community was observed, most likely due to glyphosate acting as an available source of C, N and P. On the other hand, 30 days after herbicide treatment, both the activity and diversity of the rhizosphere soil microbial communities showed an inconsistent response to glyphosate addition. Apart from its intended effect on plants, glyphosate had non-target effects on the rhizosphere soil microbial community which were, interestingly, more enhanced in triticale than in “triticale + pea” pots. Biolog™ was more sensitive than PCR-DGGE to detect changes in soil microbial communities induced by glyphosate and plant composition.     

Long-term storage of Pink Lady apples modifies volatile-involved enzyme activities: consequences on production of volatile esters

Pink Lady apples were harvested at commercial maturity and stored at 1 degrees C and 92% relative humidity under either air or controlled atmosphere conditions (2 kPa O 2:2 kPa CO 2 and 1 kPa O 2:1 kPa CO 2) for 27 weeks. Data on the emission of volatile compounds and on the activity of some related enzymes in both skin and flesh tissues were obtained during subsequent shelf life at 20 degrees C. Major effects of storage atmosphere and poststorage period were observed on the emission of volatile esters and their precursors. Changes in the production of volatile esters were partly due to alterations in the activity of alcohol o-acyltransferase, but the specific esters emitted by fruit after storage also resulted largely from modifications in the supply of the corresponding substrates. Samples stored under air were characterized by higher availability of acetaldehyde, whereas those stored under CA showed enhanced emission of the alcohol precursors ethanol and 1-hexanol (2 kPa O 2) and 1-butanol (1 kPa O 2), with accordingly higher production of ethyl, hexyl, and butyl esters. Multivariate analysis revealed that a large part of the observed differences in precursor availability arose from modifications in the activity of the enzymes considered. Higher pyruvate decarboxylase activity in air-stored fruit possibly accounted for higher acetaldehyde levels in these samples, while storage under 1 kPa O 2 led to significantly decreased lipoxygenase activity and thus to lessened production of 1-hexanol and hexyl esters. Low acetaldehyde availability together with enhanced hydroperoxide lyase and alcohol dehydrogenase levels in these fruits are suggested to have led to higher emission of 1-butanol and butyl esters.     

Effects of natural phenolic compounds on the antioxidant activity of lactoferrin in liposomes and oil-in-water emulsions

The effect of natural phenolic compounds on the antioxidant and prooxidant activity of lactoferrin was studied in liposomes and oil-in-water emulsions containing iron. The antioxidants tested with lactoferrin were alpha-tocopherol, ferulic acid, coumaric acid, tyrosol, and natural phenolic extracts obtained from three different extra-virgin olive oils and olive mill wastewater. The natural extracts of olive oils and mill wastewaters were composed mainly of polyphenols and simple phenolics, respectively. Lipid oxidation at 30 degrees C was determined by the formation of hydroperoxides and fluorescent compounds resulting from oxidized lipid interactions. All phenolic compounds showed synergistic properties in reinforcing the antioxidant activity of lactoferrin in lipid systems containing iron. The highest synergistic effects were observed for the phenolic extracts rich in polyphenols of extra-virgin olive oils and lactoferrin. This synergistic effect was higher in liposomes than in emulsions.     

Identification of grouper (Epinephelus guaza), wreck fish (Polyprion americanus), and Nile perch (Lates niloticus) fillets by polyclonal antibody-based enzyme-linked immunosorbent assay

An indirect enzyme-linked immunosorbent assay (ELISA) has been developed for the species identification of grouper (Epinephelus guaza), wreck fish (Polyprion americanus), and Nile perch (Lates niloticus) fillets. The assay was performed in two different formats, microtiter plates and immunostick tubes, and uses polyclonal antibodies raised in rabbits against muscle-soluble proteins of grouper (anti-GSP), wreck fish (anti-WSP), and Nile perch (anti-PSP). The antibodies were made species-specific by blocking them with the heterologous soluble muscle proteins. Immunorecognition of polyclonal antibodies adsorbed to their specific fish samples was made with swine antirabbit immunoglobulins conjugated to the enzyme horseradish peroxidase. Subsequent enzymatic conversion of the substrate allowed unequivocal identification of the species studied.     

Unsaturated fatty alcohol derivatives of olive oil phenolic compounds with potential low-density lipoprotein (LDL) antioxidant and antiobesity properties

A new route for the synthesis of fatty alcohol derivatives of hydroxytyrosol and other olive oil phenolic compounds was developed to allow the preparation of unsaturated derivatives. The biological activity of synthesized compounds was evaluated. Most of the compounds presented a significant antioxidant activity on low-density lipoprotein (LDL) particles. The activity of the tested products was significantly influenced by the number and position of unsaturations as well as modifications on the polar head of the synthesized compounds. Some of them presented modulation of food intake in rats and, due to their molecular similarity with CB(1) endogenous ligands, the endocannabinoid system and PPAR-α were also evaluated as potential targets. The pharmacodynamics could not be totally explained by CB(1) and PPAR-α receptor interactions because only two of the four compounds with biological activity showed a CB(1) activity and all of them presented low PPAR-α affinity, not justifying its whole in vivo activity. The hydroxytyrosol linoleylether (7) increased LDL resistance to oxidation with a capacity similar to that of hydroxytyrosol and was the most active in vivo compound with a hypophagic effect comparable to that of oleoylethanolamine. We consider that this compound could be a good lead compound for future drug development in obesity treatments.     

Canopy fuel characteristics in relation to crown fire potential in pine stands: analysis, modelling and classification

Crown fire occurrence and subsequent crown fire behaviour are strongly dependent on canopy fuel characteristics, especially canopy fuel load (CFL), canopy bulk density (CBD) and canopy base height (CBH). Therefore, quantification of such variables is required for the appropriate selection of silvicultural treatments aimed at reducing susceptibility to crown fire. Data from the IV Spanish National Forest Inventory and individual tree biomass dry weight equations were used to estimate the canopy fuel characteristics of four representative types of pine stands in north-western Spain. Probability of crown fire initiation and crown fire rate of spread were simulated by using the mean surface fuel load observed for each type of pine in this area and assuming different burning conditions. The results indicate that a 22.13 % of the sample plots analysed showed a rather high potential for active crown fire spread under moderate burning conditions, and this value increases to 69.27 % under extreme burning conditions. Equations relating the canopy fuel characteristics to common stand variables (stand density, basal area and dominant height) were fitted simultaneously for each pine, and weighting factors for heteroscedasticity were included. The models explained more than 93.90, 74.70 and 69.42 % of the observed variability in CFL, CBD and CBH, respectively. Basal area was the most important variable for estimating CFL and CBD while dominant height explained most of the observed variability in CBH. The use of the fitted equations together with existing dynamic growth models and fire management decision support systems will enable assessment of the crown fire potential associated with different silvicultural alternatives used in these types of pine stands.     

Evaluation of a covalent mix-enzyme linked immunosorbent assay for screening of Salmonella antibodies in pig serum

In this study, a commercial Salmonella covalent mix-enzyme linked immunosorbent assay (ELISA) for serological detection of Salmonella infection in swine was evaluated by comparing it with the conventional fecal culture method and inter-laboratory proficiency testing, using a panel of sera tested in 5 laboratories from Europe and North America. Comparison with culture results showed that 88.5% of 26 culture-positive animals were ELISA positive, as were 55% of 60 animals from 2 culture-positive pig herds. Of 90 animals from 2 high health farms with no clinical symptoms of salmonellosis, 98.9% tested negative. The interlaboratory comparison study found a kappa value of 0.9 between our laboratory (using an automated system) and the manufacturer laboratory (using the manual method). Comparison of ELISA results from all 5 participating laboratories showed very good to excellent agreement, between 85% and 97.5%. We found this assay to be useful for the screening of antibodies against Salmonella present in swine serum. It agrees well with bacterial cultures, is reproducible, sensitive, specific, repeatable, and suitable for automation.     

Black pine (Pinus nigra Arn.) growth divergence along a latitudinal gradient in Western Mediterranean mountains

? Most studies of tree-growth and climate report positive responses to global warming in high latitudes and negative responses at lower ones.

? We analyzed tree-ring width of Pinus nigra Arn. along a 500 km latitudinal transect in the Iberian Peninsula to study the temporal trend and climate forcing in tree radial growth during the last century.

? Tree growth was enhanced by cool summers and moist cold seasons. Increased moisture stress has decreased tree growth rates. However, we present evidence of growth increases in some trees in all sampled populations after 1980’s. Climate change negatively (positively) affected between 72% (5%) of trees in the southern populations and 40% (25%) in the north Trees with positive growth trends were favored by winter temperatures and their abundance was inversely correlated with forest productivity.

? Our findings add evidences of tree growth divergence in the Mediterranean basin and show the gradual transition between forests where positive (temperate and boreal) and negative (Mediterranean) growth trends dominate.

     

Genetic evaluation of IS900 partial sequence of Mycobacterium avium subsp. paratuberculosis Brazilian isolates from bovine milk

Mycobacterium avium subsp. paratuberculosis (MAP) is the causative agent of paratuberculosis. Insertion sequence IS900 is used for the identification of MAP. The objective of this study was to verify the genetic conservation of IS900 sequences in raw milk samples. To evaluate genetic conservation, 206 quarter milk samples and 16 bulk-tank milk samples were collected. DNA extraction and IS900 PCR were performed in all samples. Six samples amplified the expected fragment. To confirm the identity of the amplified fragments, PCR products were cloned and sequenced. The resulting sequences were compared with other MAP sequences from GenBank, and it was possible to identify eight polymorphic regions and to form five distinct haplotypes. The number of mutations in each haplotype was verified. IS900 sequence is a very well-conserved sequence that could be used as tool for the molecular detection of this agent and epidemiological purposes. The results showed the first genetic analysis on Brazilian isolates of MAP.     

Neuropathotyping: a new system to classify Marek's disease virus

A statistical approach was used to establish a new classification system of Marek's disease virus (MDV) on the basis of neurologic responses. To develop the system, neurologic response data from 15x7 chickens inoculated with 30 strains of serotype 1 MDV were statistically analyzed by a cluster analysis. The goal was to identify a statistical system that would verify if three neurovirulence groups correlated with the three pathotypes previously described. The system was also validated in two additional strains of specific-pathogen-free (SPF) chickens, SPAFAS and line SC (Hy-Vac). The proposed system is based on analysis of three variables: 1) frequency of birds showing transient paralysis between 9 and 11 days postinoculation (dpi), (2) mortality before 15 dpi, and (3) frequency of birds showing persistent neurologic disease between 21 and 23 dpi. By use of this system, a MDV may be classified in one of three groups, designated neuropathotypes A, B, and C, which roughly correspond to the virulent, very virulent, and very virulent plus pathotypes, respectively. However, correlation between neuropathotype and pathotype was not absolute, and neuropathotyping is more a complement to the current pathotyping system than a replacement for it. Our results showed that neuropathotyping studies can be conducted in two types of commercial SPF chickens by the use of the same variables, although the system would first have to be standardized by the use of prototype viruses. Neuropathotypes can also be estimated with our statistical analysis with reasonable accuracy. By use of this analysis, we established that MDV strains within the very virulent pathotype may be subdivided into neuropathotypes B and C, thus establishing a previously unrecognized pathotypic classification. This finding illustrates how neuropathotyping may extend important information not identified by conventional pathotyping.