Current status of rodents on islands in the Gulf of California

On islands in the Gulf of California, many species and subspecies of rodents are relict species, restricted to the islands, and now considered extinct or verging on extinction. From 1991 to 1999, each island was surveyed and an average of 15 work-nights were spent on each island, for a total of 15,000 trap-nights. A Fourier series was used to estimate population density. Five native taxa are now considered extinct (Chaetodipus baileyi fornicatus, Peromyscus guardia mejiae, P. g. harbinsoni, P. pembertoni, and Neotoma bunkeri). Two species are at risk of extinction (Dipodomys insularis and Neotoma albigula varia). The most probable cause for extinction is the introduction of nonnative species, specifically cats. We believe that the most vulnerable rodent populations of the islands in the Gulf of California to non-native species are Neotoma lepida latirostra on Danzante island and Neotoma lepida abbreviata on San Francisco island, both in the state of Baja California Sur.     

Supercritical extraction of essential oil from aniseed (Pimpinella anisum L) using CO2: solubility,kinetics, and composition data

Supercritical fluid extraction (SFE) from aniseed using carbon dioxide was performed at 30 degrees C and pressures of 80-180 bar. The chemical composition of the SFE extract was determined by GC-MS; the quantitative analysis was done by GC-FID and TLC. The total amount of extractable substances or global yield (mass of extract/mass of feed) for the SFE process varied from 3.13 to 10.67% (mass). The solubilities of the anise essential oil in CO(2) were 0.0110, 0.0277, 0.0143, and 0.0182 kg of solute/kg of CO(2) at 80, 100, 140, and 180 bar, respectively. The major compounds identified and quantified in the extracts were anethole ( approximately 90%), gamma-himachalene (2-4%), p-anisaldehyde (<1%), methylchavicol (0.9-1.5%), cis-pseudoisoeugenyl 2-methylbutyrate ( approximately 3%), and trans-pseudoisoeugenyl 2-methylbutyrate ( approximately 1.3%). The Sovová model described quite well the experimental overall extraction curves.     

Adaptive selection of foraging and nesting habitat by black kites (Milvus migrans) and its implications for conservation: a multi-scale approach

Black kites (Milvus migrans) are vulnerable and in decline within Europe. Here, we investigate selection of foraging and breeding habitat in a high-priority population in the Italian pre-Alps. Compared to a random distribution, kites foraged preferentially near water, over extensively managed grassland and within 1 km of nest-sites. Urban areas were positively selected near lakes but otherwise avoided. Foraging performance was higher over water than over terrestrial habitats. Kites nested on cliffs and trees and preferentially near water, far from paths and villages and in rugged and steep micro-sites. Tree-nests were located in the most mature tree in the stand. Productivity was positively related to the availability of water bodies. Therefore, food availability and human disturbance/persecution limited foraging and breeding performance. Guidelines to maintain or enhance current population levels include: (1) setting up reserves covering 10% of the areas within 1 km of large lakes; (2) converting current derelict coppice-woodland to high forest; and (3) enhancing subsidies for extensively managed grassland. Our results highlight the importance of cross-scale models integrating selection of foraging and breeding habitat and reinforce the importance of the spatial configuration of key resources for more realistic conservation management in mosaic landscapes.     

Antioxidant properties of trans-epsilon-viniferin as compared to stilbene derivatives in aqueous and nonaqueous media

trans-Epsilon-viniferin, the dimer of resveratrol, extracted from Vitis vinifera, has been evaluated for its antioxidant capacity. Its properties have been compared to those of resveratrol and synthetic stilbenic derivatives (4-hydroxystilbene, 4,4'-dihydroxystilbene, 3,5-dihydroxystilbene, and trimethylresveratrol), in regard to their liposolubility using two media with different polarity. The bleaching of beta-carotene by lipoperoxyl (LOO.) radicals in an oil/water (O/W) emulsion and the scavenging of superoxide anions (O(-)(2) in dimethyl sulfoxide (DMSO) using 5,5-dimethyl-1-pyrroline-N-oxide as a spin trap were followed using UV-visible and electron paramagnetic resonance, respectively. Epsilon-viniferin exhibits the best antioxidant capacity in the DMSO/O(-)(2) polar system (IC(50) = 0.14 mM) while 4,4'-dihydroxystilbene presents the highest antioxidant capacity in the O/W/LOO. system (inhibition of beta-carotene bleaching, 82%). Partition coefficients and kinetics of partition between 1-octanol and water were measured to discuss the antioxidant efficiency of the compounds in relation with their chemical structure.     

Generation of a Mixolab Profile After the Evaluation of the Functionality of Different Commercial Wheat Flours for Hot‐Press Tortilla Production

Refined wheat flours commercially produced by five different U.S. and Mexican wheat blends intended for tortilla production were tested for quality and then processed into tortillas through the hot‐press forming procedure. Tortilla‐making qualities of the flour samples were evaluated during dough handling, hot pressing, baking, and the first five days on the shelf at room temperature. The predominant variables that affected the flour tortilla performance were wet gluten content, alveograph W (220–303) and P/L (0.70–0.94) parameters, farinograph water absorption (57%) and stability (10.8–18.7 min), starch damage (5.43–6.71%), and size distribution curves (uniform particle distribution). Flours produced from a blend of Dark Northern Spring (80%) and Mexican Rayon (20%) wheat had the highest water absorption, and tortillas obtained from this blend showed the highest diameter and lowest thickness. The whitest and best textured tortillas were obtained from the flour milled from three hard types of Mexican wheat blend. A Mixolab profile was generated from the best tortilla flours, those produced by mills 3 and 4. The Mixolab profile showed that a good flour for hot‐press tortillas had a relatively lower absorption and short dough mix time compared with a bread flour and should have a significantly higher gluten compared with an all‐purpose flour. Compared with bread flour, the tortilla flour had higher retrogradation and viscosity values. The Mixolab profile proved to be a good preliminary test to evaluate flours for hot‐press tortillas.     

Effect of the number of intercrosses on grain yield in basic rice synthetic populations

The effect of 0, 1, 2, 3 and 4 intercross cycles using genetic male sterility on the mean yield and genetic variability of the CNA 5 irrigated rice synthetic population was assessed studying 300 S_0:2 (1998/99) and S_0:3 (1999/00) families grown in two locations (Lambari, MG and Goianira, GO). Each intercross was investigated using a 8 × 8 triple lattice design experiment containing 60 families and four control cultivars. Five experiments were carried out per location and generation, totaling 20 experiments. Individual, combined over locations, combined over generations and combined over locations and generations analyses of variance were performed. Linear regression equations were fitted to data of each location and generation as well as, genetic and phenotypic parameters were estimated. An average increase of 3.91% in grain yield was obtained with the increase in the number of intercrosses. However, when genetic gains obtained from selection of the five and ten highest yielding families were considered, negative b estimates were always obtained, suggesting a tendency of gain increase reduction with the increase in the number of intercrosses. This was confirmed by the analysis of the means of the best families, since increases in the number of intercrosses did not result in selection of families with greater mean grain yield. The estimates of the genetic variances and heritabilities did not suggest an increase in genetic variability with the increase in intercross cycles. Therefore, carrying out intercrosses on the base population did not improve the results of the irrigated rice recurrent selection program. This revised version was published online in August 2006 with corrections to the Cover Date.     

Risk assessment of dietary exposure to pesticides using a Bayesian method

Risk assessment of pesticides can be a statistically difficult problem because pesticides occur only occasionally, but they may occur on multiple components in the diet. A Bayesian statistical model is presented which incorporates multivariate modelling of food consumption and modelling of pesticide measurements which are for a large part below a measurement threshold. It is shown that Bayesian modelling is feasible for a limited number of food components, and that in a data-rich situation the model compares well with an empirical Monte Carlo modelling.     

Genetic and antigenic characterization of the surface lipoprotein P48 of Mycoplasma bovis

The presence of a membrane lipoprotein homologous to the P48 of Mycoplasma agalactiae was investigated in different Mycoplasma bovis isolates selected by geographical locations and biological properties. Its potential as a diagnostic tool was also discussed. The presence of a specific signal observed in all M. bovis field isolates probed with a rabbit antiserum raised against the M. agalactiae recombinant P48 demonstrated that this protein is structurally and antigenically conserved within the M. bovis cluster. No signal was detected when testing six different mycoplasma species found in cattle. The p48 gene was identified by PCR approach and partially sequenced. Full length gene sequence was obtained by direct bacterial chromosome sequencing. Five UGAs were selectively mutated into UGG and the full length mutated gene, lacking the signal peptide, was cloned and expressed in Escherichia coli. The purified recombinant antigen (r-P48) was evaluated as a potential marker of infection using a panel of 86 well-characterized sera from experimentally and naturally infected cattle. Specific IgM antibodies were detected within 6-9 days after experimental infection followed by an IgG response lasting from the third/fourth week after contact. Although antibody titers were well below those observed in sheep or goats infected with M. agalactiae, results suggest that M. bovis r-P48 can be used as a specific marker of infection.     

Risk of postnatal exposure to Sarcocystis neurona and Neospora hughesi in horses

OBJECTIVE: To estimate risk of exposure and age at first exposure to Sarcocystis neurona and Neospora hughesi and time to maternal antibody decay in foals. ANIMALS: 484 Thoroughbred and Warmblood foals from 4 farms in California. PROCEDURE: Serum was collected before and after colostrum ingestion and at 3-month intervals thereafter. Samples were tested by use of the indirect fluorescent antibody test; cutoff titers were > or = 40 and > or = 160 for S neurona and N hughesi, respectively. RESULTS: Risk of exposure to S neurona and N hughesi during the study were 8.2% and 3.1%, respectively. Annual rate of exposure was 3.1% for S neurona and 1.7% for N hughesi. There was a significant difference in the risk of exposure to S neurona among farms but not in the risk of exposure to N hughesi. Median age at first exposure was 1.2 years for S neurona and 0.8 years for N hughesi. Highest prevalence of antibodies against S neurona and N hughesi was 6% and 2.1 %, respectively, at a mean age of 1.7 and 1.4 years, respectively. Median time to maternal antibody decay was 96 days for S neurona and 91 days for N hughesi. There were no clinical cases of equine protozoal myeloenchaphlitis (EPM). CONCLUSIONS AND CLINICAL RELEVANCE: Exposure to S neurona and N hughesi was low in foals between birth and 2.5 years of age. Maternally acquired antibodies may cause false-positive results for 3 or 4 months after birth, and EPM was a rare clinical disease in horses < or = 2.5 years of age.