Effect of Particle Size and Reused Organic Substrates on Tomato Crop Production

The bagasse of mezcal maguey and the fiber of coconut fruit are organic byproducts of the mezcal and copra agro-industries in Oaxaca, Mexico. The effects of different particle sizes and prior usage times as substrates on the production and quality of tomato (Lycopersicon esculentum Mill) were studied. Three independent and simultaneous experiments were conducted in multi-tunnel greenhouses. Three prior growing cycles of tomato crop, each 150 days in length days of use (DOU), were used for the usage time experiments with mezcal maguey bagasse as the growth medium. In the first experiment, tomato plants grown on substrate with 150 DOU produced the highest yields, the largest number of commercial quality fruits and the fewest non-commercial quality fruits. In the second experiment, the combination of fine particle size and maguey bagasse substrate with 150 DOU produced the highest yields. In the third experiment, fine and medium-sized particles of maguey bagasse and coconut fiber produced the highest yields. The data indicate that both coconut fiber and mezcal maguey bagasse can be used as substrates for tomato cultivation without affecting fruit quality; furthermore, the use of fine and medium-sized particles increases production. Maguey bagasse with up to 150 DOU as a substrate is best for culture, as prior usage beyond this length of time negatively affects production.     

Anti-proliferative Effect of <Emphasis Type="Italic">Melissa officinalis</Emphasis> on Human Colon Cancer Cell Line

Melissa officinalis L. (Lamiaceae) is consumed as a traditional herbal tea in the Mediterranean region. The cytotoxic effect of the 50% ethanolic and aqueous extract, determined by the MTT and NR assays, was evaluated in vitro on Human Colon Cancer Cell Line (HCT-116), using Triton 10% as positive control. The 50% ethanolic extract showed significant differences after 72 h of treatment, reducing cell proliferation to values close to 40%, even the lowest dose tested (5 μg/ml). In the MTT assay, the same extract caused the lowest cell viability with 13% at a concentration of 1,000 μg/ml after 72 h of treatment, being a value lower than Triton 10%. The antioxidant activity was also confirmed evaluating the capacity of the extracts to scavenge ABTS and DPPH radicals, and IC₅₀ values were highly correlated with the total phenolic and flavonoid content. Bioassay guided fractionation led to the isolation of an anti-proliferative compound, rosmarinic acid. Its structural elucidation was performed by HPLC/DAD/ESI/MS analysis. High dose of rosmarinic acid (1,000 μg/ml) was clearly cytotoxic against HCT-116 cells, with a significant decrease in cell number since the earliest time point (24 h).     

Compositional variation amongst sorghum hybrids: Effect of kafirin concentration on metabolizable energy

Kafirins are stored proteins that negatively affect the nutritional quality of sorghum grain. Kafirin concentration and other chemical characteristics were determined in 12 sorghum hybrids and varied significantly, from 58% (HB1) to 42% (HB12) as percent total protein. Kafirin concentration correlated negatively with crude protein (CP) (−0.49), with acid detergent fiber (−0.40), apparent metabolizable energy (−0.61), and true metabolizable energy corrected for N (−0.63). HB12 was the hybrid with the lowest content of kafirins, amylose and tannins, and the highest content of apparent metabolizable energy. No differences were observed in the concentration of starch, but differences were found in apparent metabolizable energy (3325–2944 kcal kg⁻¹) probably due to a greater availability of starch, related to differences in kafirin concentration.     

Evolution of introduced Chinook salmon (Oncorhynchus tshawytscha) in Lake Huron: emergence of population genetic structure in less than 10 generations

Abstract – Population genetic structure was detected in Chinook salmon Oncorhynchus tshawytscha in their non‐native range of Lake Huron using microsatellite DNA. All Chinook salmon in this system descend from Green River, Washington cohorts, originally transplanted to Michigan hatcheries in the late 1960s. We tested for population genetic differentiation of age 0 fish collected from 13 rivers and two hatcheries in 2007. The amount of genetic differentiation among collection sites was low but statistically significant, with F_ST values ranging from 0.036 to 0.133 and R_ST values ranging from 0.008 to 0.157 for specific loci. Based on pairwise F_ST and R_ST values and Bayesian cluster analysis, the Maitland River population in the Main Basin of Lake Huron was genetically distinct from the remaining collection sites. Based on analysis of bycatch data from commercial gill net fisheries, Chinook salmon likely colonised the Main Basin by 1975 (10 generations ago) and the North Channel and southern Georgian Bay regions by 1980 (eight generations ago). Thus, population genetic structure has emerged in Lake Huron Chinook salmon in <10 generations.     

Detection and characterization of methicillin-resistant Staphylococcus pseudintermedius in healthy dogs in La Rioja, Spain

The objective was to identify the methicillin-resistant coagulase-positive staphylococci (MRCoPS) nasal carriage rate of healthy dogs in La Rioja (Spain) and to characterize the recovered isolates by different molecular techniques. Nasal samples from 196 dogs were obtained (98 household-dogs, 98 pound-dogs). Isolates were identified and characterized by spa-, SCCmec- and MLST-typing, SmaI-PFGE, antimicrobial susceptibility, determination of antimicrobial resistance and toxin genes profiling. S. pseudintermedius was the only species recovered. Nine methicillin-resistant S. pseudintermedius (MRSP) were obtained from 9 of 196 sampled dogs (8% pound-dogs, 1% household-dogs). MRSP isolates were typed (MLST/PFGE/spa/SCCmec) as: ST71/A/t02/II–III (7 isolates), ST92/C/t06/V (1 isolate), and ST26/B/non-typable/non-typable (1 isolate). All MRSP were resistant to [resistance gene/number isolates]: β-lactams [mecA + blaZ/9], tetracycline [tet(K)/7, tet(M)/2], macrolides and lincosamides [erm(B)/9], aminoglycosides [aacA-aphD + aadE + aphA-3/9], and co-trimoxazol [dfr(G)/9]. Eight MRSP isolates showed also resistance to fluoroquinolones and amino acid changes in GyrA [Ser84Leu + Glu714Lys, 7 isolates; Ser84Leu, 1 isolate] and GrlA [Ser80Ile, 8 isolates] proteins were detected. The remaining isolate was chloramphenicol resistant and harboured cat_pC221 gene. All MRSP isolates harboured the aadE-sat4-aphA-3 multiresistance-gene-cluster linked to erm(B) gene as well as the siet, si-ent and lukS/F-I toxin genes. MRSP is a moderately common (4.6%) colonizer of healthy dogs in Spain. A major MRSP lineage (ST71) was detected and its future evolution should be tracked.     

Bacterial Bioeffectors Modify Bioactive Profile and Increase Isoflavone Content in Soybean Sprouts (Glycine max var Osumi)

The effect of two bacterial strains to enhance bioactive contents (total phenolic compounds, total flavonoid compounds and isoflavones) and antioxidant activity on 3-day-old soybean sprouts were investigated. To identify bacterial determinants responsible for these effects, viable and UV-treated strains were delivered to wounded seeds at different concentration. Multivariate analysis performed with all the evaluated parameters indicated the different effectiveness of Stenotrophomonas maltophilia N5.18 and Pseudomonas fluorescens N21.4 based on different structural and metabolic determinants for each. N21.4 increased total phenolics and isoflavones from the genistein family, while N5.18 triggered biosynthesis of daidzein and genistein families coupled to a decrease in total phenolics, suggesting different molecular targets in the phenilpropanoid pathway. Only extracts from N5.18 treated seeds showed an improved antioxidant activity according to the β-carotene bleaching prevention method. In summary, bioeffectors from both bacterial strains are effective tools to improve soybean sprouts quality; structural elicitors from N5.18 also enhanced antioxidant activity, being the best alternative for further development of a biotechnological procedure.     

Assessment of iron bioavailability in whole wheat bread by addition of phytase-producing bifidobacteria

In this study, the influence of phytase-producing Bifidobacterium strains during the breadmaking process (direct or indirect) on final bread Fe dialyzability and ferritin formation in Caco-2 cell as a measure of cell Fe uptake was assessed. The addition of bifidobacteria significantly reduced the InsP(6) + InsP(5) concentrations compared to control samples. Fe-dialyzable contents for samples with bifidobacteria were increased 2.3-5.6-fold, and dialyzability was improved by 2.6-8.6% compared to controls. However, this was not reflected in an increase of Fe uptake by Caco-2 cells as was predicted by the phytate/Fe molar ratios. The results demonstrated the usefulness of phytase-producing bifidobacteria to reduce phytate during the breadmaking process and to increase Fe accessibility, although the effects appeared to be still insufficient to improve Fe bioavailability in Caco-2 cells. Further refinement of the use of phytase-producing bifidobacterial strains and/or breadmaking technological processes is deserved for improving Fe uptake.     

Evaluation of Passive Samplers as a Monitoring Tool for Early Warning of Dinophysis Toxins in Shellfish

From June 2006 to January 2007 passive samplers (solid phase adsorbing toxin tracking, SPATT) were tested as a monitoring tool with weekly monitoring of phytoplankton and toxin content (liquid chromatography–mass spectrometry, LC-MS) in picked cells of Dinophysis and plankton concentrates. Successive blooms of Dinophysis acuminata, D. acuta and D. caudata in 2006 caused a long mussel harvesting closure (4.5 months) in the Galician Rías (NW Spain) and a record (up to 9246 ng·g resin-week⁻¹) accumulation of toxins in SPATT discs. Best fit of a toxin accumulation model was between toxin accumulation in SPATT and the product of cell densities by a constant value, for each species of Dinophysis, of toxin content (average) in picked cells. Detection of Dinophysis populations provided earlier warning of oncoming diarrhetic shellfish poisoning (DSP) outbreaks than the SPATT, which at times overestimated the expected toxin levels in shellfish because: (i) SPATT accumulated toxins did not include biotransformation and depuration loss terms and (ii) accumulation of toxins not available to mussels continued for weeks after Dinophysis cells were undetectable and mussels were toxin-free. SPATT may be a valuable environmental monitoring and research tool for toxin dynamics, in particular in areas with no aquaculture, but does not provide a practical gain for early warning of DSP outbreaks.