Characterization,Pathogenicity and Chemical Control of <Emphasis Type="Italic">Streptomyces acidiscabies</Emphasis> Associated to Potato Common Scab

The pathogenicity of 10 bacterial isolates was investigated on potato, radish, carrot and beet, including sensitivity and pathogen control efficacy. The isolates were identified by morphological, biochemical and molecular methods. All isolates were pathogenic on radish, carrot, and beet, and were highly virulent on potato. Although the isolates were obtained from different locations in the El Fuerte Valley (Sinaloa, Mexico), they were similar in their morphological, physiological and biochemical characteristics. Sequences of the 16S rRNA gene obtained by PCR were identical for all isolates. These results indicate that the bacterial isolates from potato scabby tissue belong to S. acidiscabies. Furthermore, the effectiveness of fluazinam, both in vitro and under greenhouse and field conditions, represents a possibleoption for chemical control of potato common scab disease. While our results suggest that spraying at seeding is effective in controlling common scab, future studies to combine this treatment with seed dressing before planting will be conducted to determine if there is an increase in disease control.     

Physicochemical and Structural Properties of Recovered Elastin from Jumbo Squid (Dosidicus gigas) By-Products

Physicochemical and structural properties of soluble jumbo squid (Dosidicus gigas) elastin recovered from skin by-products were evaluated. The molecular weight of isolated elastin was ~40 kDa with an isoelectric point (pI) between 9 and 10. Aspartic, glutamic, arginine, proline, glycine, and lysine amino acids were the most abundant in squid elastin, whereas the hydroxyproline absence, ~0.7% cysteine content, and the calculated 0.35 isoleucine/leucine ratio were used as purity index. Total and reactive sulfhydryl contents were similar (247.0 ± 5.1 vs 242.0 ± 7.5 μmol mg^?1 of protein, P ≥ 0.05) in purified squid elastin but surprisingly higher than previously reported in other elastins. On the other hand, the secondary structures of squid elastin analyzed by Fourier transform infrared spectroscopy (FTIR) were ~45% β-sheets, ~15% α-helices, ~10% β-turns, and ~30% undefined structures. In addition, squid elastin experienced glass transition at 82.01 ± 0.01ºC, denaturation temperature at 110.45 ± 0.64ºC, and aggregation at 197.5 ± 0.23ºC. In conclusion, the prevalence of charged amino acids and pI of squid elastin can facilitate its solubilization in hydrophilic systems, whereas the secondary structure profile and thermostability are desirable features in proteins used for biopolymer designs such as food biofilms or barrier systems.     

Chemopreventive activity of polyphenolics from black Jamapa bean (Phaseolus vulgaris L.) on HeLa and HaCaT cells

The antiproliferative effects of 100% methanol crude extract and of Toyopearl and silica gel fractions from the seed coats of black Jamapa beans (Phaseolus vulgaris L.) were evaluated using HeLa, human adenocarcinoma cells, and HaCaT, human premalignant keratinocytes. The 100% methanol crude extract [172.2 microM equiv of (+)-catechin] increased adhesion of HeLa cells; however, 3- and 5-fold higher concentrations decreased the number of cells attached as a function of the treatment time. The highest concentration tested diminished the cell adhesion until 40% (after 24 h) to almost 80% (after 72 h). The IC50 values showed that the 100% methanol crude extract was the most effective inhibitor of HeLa cell proliferation, even when it was dissolved in dimethylsulfoxide (DMSO) [34.5 microM equiv of (+)-catechin] or in medium [97.7 microM equiv of (+)-catechin]. The Toyopearl 5 (TP5) fraction and silica gel 2 (SG2) fraction inhibited 60% of the HeLa cell proliferation. The IC50 was 154 microM equiv of (+)-catechin of the 100% methanol crude extract on HaCaT cells. Toyopearl fractions TP4 and TP6 significantly inhibited HaCaT cell proliferation, but the silica gel fractions did not have a significant effect. The 100% methanol crude extract (35 microg of dry material/mL) decreased the number of HeLa cells in the G0/G1 phase from 68.9% (for control cells) to 51.4% (for treated cells) and increased apoptosis (2.9 and 21.2% for control and treated cells, respectively). The results indicated that black Jamapa beans could be a source of polyphenolic compounds, which have an inhibitory effect toward HeLa cancer cells but are less aggressive on HaCaT premalignant cells.     

Effect of the Cooking Process on the Gelling Properties of Whole and Minced Jumbo Lump of Blue Crab (Callinectes sapidus)

Commercially, crab meat is obtained by hand-picking after a cooking process, followed by pasteurizing or canning. Jumbo lump is one of the pieces of meat obtained from the blue crab. The aim of this study was to evaluate the effect of the commercial cooking process (boiling and steaming) on the mechanical and functional properties of whole jumbo lump and the gels obtained from cooked and minced jumbo lump from blue crab (Callinectes sapidus). The gels were prepared combining the washing process and microbial transglutaminase. The boiling and steaming processes showed a different effect on the textural and color properties. Whole jumbo lump pieces cooked by immersion in boiling water showed a higher hardness value as compared to steamed jumbo lump pieces, suggesting a different internal structural. The cooking processes used in this study did not modify the water holding capacity, gelling capability, or color of the minced jumbo lump. The addition of microbial transglutaminase to washed minced jumbo lump improved the hardness, cohesiveness, and chewiness of gels elaborated with boiled or steamed jumbo lump, which allowed the textural properties similar to those of the whole jumbo lump.     

Antioxidant Capacity and Antimutagenic Activity of Natural Oleoresin from Greenhouse Grown Tomatoes (<Emphasis Type="Italic">Lycopersicon esculentum</Emphasis>)

Natural oleoresins rich in lycopene were obtained from two varieties of tomato (Zedona and Gironda) and their nutraceutical potential (antioxidant and antimutagenic capacity) was evaluated. Both oleoresins had a high content of lycopene, 58.33 ± 1.67 mg/g (Zedona) and 63.97 ± 0.80 mg/g (Gironda). The antioxidant activity (AA) of the oleoresins by β-carotene method were 56.4–74.5% (Zedona) and 51–72.8% (Gironda), while when using the free radical stable 2,2-diphenyl-picryl-hydrazyl (DPPH) method, the antiradical activity (ARA) was determined to be 18.2–32.7% (Zedona) and 16.6–26.7% (Gironda) for the concentrations tested that of 200–400 μM equivalents of lycopene. The antimutagenic activity of the oleoresins was tested against aflatoxin B₁ (AFB₁) using the microsuspension assay, both varieties had a very high antimutagenic potential against AFB₁ (60–66%).These results suggest the NCRT can be taken advantage to obtaining rich oleoresin in lycopene with a nutraceutical value.     

Reproductive outcomes of anestrous goats supplemented with spineless Opuntia megacantha Salm-Dyck protein-enriched cladodes and exposed to the male effect

Tropical Animal Health and Production - The possible influence of the “male effect” upon reproductive outcomes of adult anestrous goats under marginal rangeland conditions and...     

Digestibility and Acceptability of Wheat Flour Cookies Partially Substituted with High Amylose Maize Starch

Plant Foods for Human Nutrition - Cookies are one of the most consumed bakery products and the formulation could be modified to consider them as a functional food. The high amylose maize starch...     

Genetic parameters for spawning and growth traits in the Pacific white shrimp (Penaeus (Litopenaeus) vannamei)

The aim of this study was to estimate genetic parameters for spawning traits and growth traits in a breeding line of Pacific white shrimp, Penaeus (Litopenaeus) vannamei, selected for growth and survival. Traits studied were number of eggs (NE) and number of nauplii (NN) and female body weight at insemination (FWI) and body weight at 130 days of age (BW130). Genetic parameters were estimated using a multivariate animal model. Heritability for NE and NN were estimated as 0.13 ± 0.04 and 0.03 ± 0.04 respectively. The contribution to NN total variation due to ‘factors associated with male’ effect was estimated as 0.47 ± 0.07. In the cases of FWI and BW130, heritability was estimated as 0.44 ± 0.08 and 0.19 ± 0.03 respectively. Genetic correlation between FWI and NE was estimated as 0.49 ± 0.15, between FWI and NN as 0.54 ± 0.39 and between NE and NN as 0.27 ± 0.41, whereas the genetic correlations of FWI, NE and NN with BW130 were 0.30 ± 0.13, ?0.21 ± 0.19 and ?0.25 ± 0.38 respectively. Although it is important to perform more studies on this issue, our results found no evidence of a genetic antagonistic effect between female reproductive traits and body weight at harvesting (130 days of age) in P. vannamei.     

Effects of polymerization changes in maize proteins during nixtamalization on the thermal and viscoelastic properties of masa in model systems

Although nixtamalization is widely used in the food industry, a comprehensive understanding of the influence of proteins on the viscoelastic behavior and thermal properties in masa is still lacking. In this work, the effect of protein changes and its influence on the masa viscoelastic behavior were studied using model systems. Mixtures of lime-starch, zein-starch and lime-zein-starch were cooked at 90 °C from 20 to 150 min. Zein changes during cooking were analyzed by SDS-PAGE. Thermal transition temperatures and enthalpies were determined using differential scanning calorimetry (DSC). Dynamic oscillatory tests were undertaken on model system samples with 50% (w/v) moisture content, using a strain-controlled rheometer. SDS-PAGE showed that zein polymerizes during cooking. In the zein-starch model system, no visible protein bands were found after 30 min cooking; however, when lime was present, five bands were observed in all samples. Thermal transitions were observed around 55–62 °C for all model systems, probably corresponding to starch retrogradation. Rheological studies showed that protein exhibited higher influence in the gel strength by increasing the elastic character of the system. It was hypothesized that the combined effects of lime on starch, zein polymerization and the formation of calcium-zein bonds during cooking, yield a stronger and more elastic gel structure.     

Effect of nixtamalization on morphological and rheological characteristics of maize starch

Nixtamalization of maize grain is an ancient process that until now is used for tortilla production. This thermal-alkaline process produces important changes in morphology and rheological characteristics of starch that is the major component of maize. The aim of this study was to evaluate changes in the morphological and rheological properties of starch brought by nixtamalization of maize using image analysis and dynamic rheometry, respectively. Nixtamalized maize starch (NS) presented granule sizes higher than starch isolated from raw maize (S) due to the partial swelling produced in the nixtamalization process. In dynamic tests during the retrogradation kinetics, an inverse effect of the temperature was observed in the re-arrangement of starch components. NS was affected due to the thermal-alkaline process presenting an annealing that provoked a reduction in its ability to develop gels. This information is important during the processing of nixtamalized maize to masa and tortilla production.