Responses of tribolium castaneum to olfactory cues from cotton seeds, the fungi associated with cotton seeds, and cereals

We tested, in an olfactometer, whether or not Tribolium castaneum Herbst (Coleoptera: Tenebrionidae) responds preferentially to the volatiles that emanate from the fungi associated with cotton [Gossypium hirsutum L. (Malvaceae)] seed over those that emanate from cereals, because cereals are usually portrayed as the primary resources of these beetles. Pairwise comparisons were conducted between cotton seed, wheat (Triticum aestivum L.), and sorghum [Sorghum bicolor (L.) Moench] (both Poaceae); volatiles were tested from intact seeds and from both water and ethanol extracts. The results demonstrate that T. castaneum is attracted more strongly to cotton seeds with its lint contaminated with fungi, than to the conventional resources of this species (i.e., wheat and sorghum). Further tests prove that it is the fungus on the lint that produces the active volatiles, because the beetles did not respond to sterilized cotton lint (i.e., without the fungi typically associated with it when cotton seed is stored). Tests with five fungal cultures (each representing an unidentified species that was isolated from the field-collected cotton lint) were variable across the cultures, with only one of them being significantly attractive to the beetles. The others were not attractive and one may even have repulsed the beetles. The results are consistent with the beetles having a strong ecological association with fungi and suggest it would be worth investigating the ecology of T. castaneum from this perspective. © 2012 The Netherlands Entomological Society.

Mango fruit peel and flesh extracts affect adipogenesis in 3T3-L1 cells

Obesity is associated with many chronic disease states, such as diabetes mellitus, coronary disease and certain cancers, including those of the breast and colon. There is a growing body of evidence that links phytochemicals with the inhibition of adipogenesis and protection against obesity. Mangoes (Mangifera indica L.) are tropical fruits that are rich in a diverse array of bioactive phytochemicals. In this study, methanol extracts of peel and flesh from three archetypal mango cultivars; Irwin, Nam Doc Mai and Kensington Pride, were assessed for their effects on a 3T3-L1 pre-adipocyte cell line model of adipogenesis. High content imaging was used to assess: lipid droplets per cell, lipid droplet area per cell, lipid droplet integrated intensity, nuclei count and nuclear area per cell. Mango flesh extracts from the three cultivars did not inhibit adipogenesis; peel extracts from both Irwin and Nam Doc Mai, however, did so with the Nam Doc Mai extract most potent at inhibiting adipogenesis. Peel extract from Kensington Pride promoted adipogenesis. The inhibition of adipogenesis by Irwin (100 mu g mL(-1)) and Nam Doc Mai peel extracts (50 and 100 mu g mL(-1)) was associated with an increase in the average nuclear area per cell; similar effects were seen with resveratrol, suggesting that these extracts may act through pathways similar to resveratrol. These results suggest that differences in the phytochemical composition between mango cultivars may influence their effectiveness in inhibiting adipogenesis, and points to mango fruit peel as a potential source of nutraceuticals.

Combining ability, genetic diversity and heterosis in relation to F1 performance of tropically adapted shrunken (sh2) sweet corn lines

With 6 tables Abstract The objectives of this study were to evaluate the importance of heterosis for agronomic and quality traits in shrunken (sh2) sweet corn, assess the usefulness of combining ability to predict the value of parents and their crosses for further genetic improvement and examine whether genetic divergence can predict heterosis or F1 performance. Ten genetically diverse shrunken (sh2) sweet corn inbred lines were used to generate 45 F1s. F1s and parents were evaluated for agronomic and quality traits across environments. Heterosis was more important for yield-related traits than it was for ear aspects and eating quality. Heterosis for most traits was mostly dependent on dominance genetic effects of parental lines. Parents and F1per se performance were highly correlated with general combining ability effects and mid-parent values, respectively, for most traits. Hybrid performance for flavour and plant height was significantly but weakly related to simple sequence repeat (SSR)-based genetic distance (GD). Phenotypic distance (PD), estimated from phenotypic traits was correlated with heterosis for total soluble solids, ear length and flavour. © 2012 State of Queensland.

Enzymatic cleavage of carotenoids

1. 1.|Carotene 15,15′-dioxygenase (EC 1.13.11.21) has been isolated from the intestine of guinea pig and rabbit and purified 38- and 30-fold, respectively, but subjecting the intestinal homogenate to protamine sulfate treatment, (NH4)2SO4 fractionation and acetone precipitation. 2. 2.|The guinea pig enzyme showed a pH optimum at 8.5, an optimum substrate concentration of 200 nmoles of β,β-carotene per 25 ml of reaction mixture, an apparent Km with β,β-carotene as substrate of 9.5 · 10−6 M and a V 3.3 nmoles of retinal formation/mg protein per h. The reaction was linear upto 3 h and the reaction rate increased linearly with increase in enzyme protein concentration. The enzyme was activated by GSH and Fe2+ and inhibited by sodium dodecylsulfate, sulfhydryl binding and iron chelating agents. 3. 3.|The reaction catalysed by guinea pig enzyme was strictly stoichiometric. 4. 4.|Rabbit enzyme showed a close similarity with guinea pig enzyme with respect to time course, optimum substrate concentration, activation by Fe2+ and GSH, inhibition by sodium dodecylsulfate, iron chelating and sulfhydryl binding agents. However, it showed a slightly lower pH optimum (pH 7.8). 5. 5.|The enzyme from guinea pig and rabbit showed remarkable similarity with respect to cleavage of carotenoids. The enzyme from both the species was more specific for β,β-carotene but could also cleave a number of other carotenoids at the 15,15′-double bond. 6. 6.|10′-Apo-β-carotenal and 10′-apo-β-carotenol were readily cleaved compared with other apo-β-carotenals and apo-β-carotenols tested. 7. 7.|It has been conclusively shown for the first time that mono-ring substituted carotenoids are also cleaved at the 15,15′-double bond.

Increase in β-Ionone, a Carotenoid-Derived Volatile in Zeaxanthin-Biofortified Sweet Corn

Carotenoids are responsible for the yellow color of sweet corn (Zea mays var. saccharata), but are also potentially the source of flavor compounds from the cleavage of carotenoid molecules. The carotenoid-derived volatile, -ionone, was identified in both standard yellow sweet corn (Hybrix5) and a zeaxanthin-enhanced experimental variety (HZ) designed for sufferers of macular degeneration. As -ionone is highly perceivable at extremely low concentration by humans, it was important to confirm if alterations in carotenoid profile may also affect flavor volatiles. The concentration of -ionone was most strongly correlated (R2 > 0.94) with the -arm carotenoids, -carotene, -cryptoxanthin, and zeaxanthin, and to a lesser degree (R2 = 0.90) with the α-arm carotenoid, zeinoxanthin. No correlation existed with either lutein (R2 = 0.06) or antheraxanthin (R2 = 0.10). Delaying harvest of cobs resulted in a significant increase of both carotenoid and -ionone concentrations, producing a 6-fold increase of ?-ionone in HZ and a 2-fold increase in Hybrix5, reaching a maximum of 62g/kg FW and 24g/kg FW, respectively.

Enzymatic acylation of 1-alkyl-, 1-alkenyl-and 1-acyl glycero-3-phosphorylethanolamine in developing rat brain

Rat brain particulate fractions were shown to acylate [32P]1-alkyl-sn-glycero-3-phosphorylethanolamine (GPE). While the main product is 1-alkyl-2-acyl GPE, about 12 per cent of the radioactivity was also found in 1-alkenyl-2-acyl GPE. The acyl transferase activity was completely dependent on added ATP and CoA and it was localized mainly in the microsomal fraction. A comparative study of acyl transferase activities to 1-alkyl-, 1-alkenyl-, and 1-acyl GPE by crude mitochondrial fraction and microsomes of 10, 16 and 22-day-old rat brains showed a progressive increase in activity with development. In the 22-day-old rat brain the order of activity towards the three substrates is as follows: 1-acyl GPE ± 1-alkenyl GPE ± 1-alkyl GPE with a crude mitochondrial fraction and 1-acyl GPE ± 1-alkyl GPE ± 1-alkenyl GPE with microsomes.

Enzymatic cleavage of carotenoids

1. 1.|Carotene 15,15′-dioxygenase (EC 1.13.11.21) has been isolated from the intestine of guinea pig and rabbit and purified 38- and 30-fold, respectively, but subjecting the intestinal homogenate to protamine sulfate treatment, (NH4)2SO4 fractionation and acetone precipitation. 2. 2.|The guinea pig enzyme showed a pH optimum at 8.5, an optimum substrate concentration of 200 nmoles of β,β-carotene per 25 ml of reaction mixture, an apparent Km with β,β-carotene as substrate of 9.5 · 10−6 M and a V 3.3 nmoles of retinal formation/mg protein per h. The reaction was linear upto 3 h and the reaction rate increased linearly with increase in enzyme protein concentration. The enzyme was activated by GSH and Fe2+ and inhibited by sodium dodecylsulfate, sulfhydryl binding and iron chelating agents. 3. 3.|The reaction catalysed by guinea pig enzyme was strictly stoichiometric. 4. 4.|Rabbit enzyme showed a close similarity with guinea pig enzyme with respect to time course, optimum substrate concentration, activation by Fe2+ and GSH, inhibition by sodium dodecylsulfate, iron chelating and sulfhydryl binding agents. However, it showed a slightly lower pH optimum (pH 7.8). 5. 5.|The enzyme from guinea pig and rabbit showed remarkable similarity with respect to cleavage of carotenoids. The enzyme from both the species was more specific for β,β-carotene but could also cleave a number of other carotenoids at the 15,15′-double bond. 6. 6.|10′-Apo-β-carotenal and 10′-apo-β-carotenol were readily cleaved compared with other apo-β-carotenals and apo-β-carotenols tested. 7. 7.|It has been conclusively shown for the first time that mono-ring substituted carotenoids are also cleaved at the 15,15′-double bond.

Polyphenolic contents and the effects of methanol extracts from mango varieties on breast cancer cells

Bioactivities of peel and flesh extracts of 3 genetically diverse mango (Mangifera indica L.) varieties were studied. Nam Doc Mai peel extracts, containing the largest amounts of polyphenols, were associated with an effect on MCF-7 viable cell numbers with an IC50 (dose required for 50% inhibition of cell viability) of 56 μg/mL and significantly (p<0.01) induced cell death in MDA-MB-231 cells, compared with other varieties. Hydrophilic fractions of Nam Doc Mai peel extracts had the highest bioactivity values against both MCF-7 and MDA-MB-231 cells. Soluble polyphenols were present in the largest amounts in most hydrophilic fractions. The Nam Doc Mai mango variety contains high levels of fruit peel bioactivity, which appears to be related to the nature of the polyphenol composition.

Bioactive Properties of Mushroom (Agaricus bisporus) Stipe Extracts

The antibacterial activity and total phenolic (TP) content of Agaricus bisporus stipes were assessed using solvent and water extracts to determine its bioactivity. Extraction methods included accelerated solvent extraction (ASE) and hot water followed by membrane concentration. Water extract from ASE had the highest TP of 1.08 gallic acid equivalents (GAE)/g dry weight (DW) followed by ethanol at 0.61 mg GAE/g DW and 0.11 mg GAE/g DW for acetone. Acetone extracts inhibited Escherichia coli and Staphylococcus aureus at less than 50%; ethanol inhibited E. coli at 61.9% and S. aureus at 56.6%; and ASE water inhibited E. coli at 78.6% and S. aureus at 65.4%. The TP content of membrane concentrated extract of mushroom was 17 mg GAE in 100 mL. Membrane concentrated water extracts had a higher percentage inhibition on S. aureus than E. coli. Overall, the results were promising for further application of mushroom stipe extracts as a functional food additive. Practical Applications Mushrooms are known for their health benefits and have been identified as a good source of nutrients. The highly perishable nature of mushrooms warrants further processing and preservation to minimize losses along the supply chain. This study explores the possibility of adding value to mushroom stipes, a by-product of the fresh mushroom industry. The extracts assessed indicate the antibacterial activity and phenolic content, and the potential of using these extracts as functional ingredients in the food industry. This study provides valuable information to the scientific community and to the industries developing novel ingredients to meet the market demand for natural food additives.

Zeaxanthin biofortification of sweet-corn and factors affecting zeaxanthin accumulation and colour change

Zeaxanthin, along with its isomer lutein, are the major carotenoids contributing to the characteristic colour of yellow sweet-corn. From a human health perspective, these two carotenoids are also specifically accumulated in the human macula, and are thought to protect the photoreceptor cells of the eye from blue light oxidative damage and to improve visual acuity. As humans cannot synthesise these compounds, they must be accumulated from dietary components containing zeaxanthin and lutein. In comparison to most dietary sources, yellow sweet-corn (Zea mays var. rugosa) is a particularly good source of zeaxanthin, although the concentration of zeaxanthin is still fairly low in comparison to what is considered a supplementary dose to improve macular pigment concentration (2 mg/person/day). In our present project, we have increased zeaxanthin concentration in sweet-corn kernels from 0.2 to 0.3 mg/100 g FW to greater than 2.0 mg/100 g FW at sweet-corn eating-stage, substantially reducing the amount of corn required to provide the same dosage of zeaxanthin. This was achieved by altering the carotenoid synthesis pathway to more than double total carotenoid synthesis and to redirect carotenoid synthesis towards the beta-arm of the pathway where zeaxanthin is synthesised. This resulted in a proportional increase of zeaxanthin from 22% to 70% of the total carotenoid present. As kernels increase in physiological maturity, carotenoid concentration also significantly increases, mainly due to increased synthesis but also due to a decline in moisture content of the kernels. When fully mature, dried kernels can reach zeaxanthin and carotene concentrations of 8.7 mg/100 g and 2.6 mg/100 g, respectively. Although kernels continue to increase in zeaxanthin when harvested past their normal harvest maturity stage, the texture of these 'over-mature' kernels is tough, making them less appealing for fresh consumption. Increase in zeaxanthin concentration and other orange carotenoids such as p-carotene also results in a decline in kernel hue angle of fresh sweet-corn from approximately 90 (yellow) to as low as 75 (orange-yellow). This enables high-zeaxanthin sweet-corn to be visually-distinguishable from standard yellow sweet-corn, which is predominantly pigmented by lutein.

Pre-emptive breeding to combine superior eating quality in tropical super sweet corn with resistance to major diseases

This report presents the process and outcomes of a five year project, which employed genetics and breeding approach for integrating disease resistance,agronomy and quality traits that enhances sustainable productivity improvement in sweet corn production. The report outlines a molecular markers based approach to introgress quantitative traits loci that are believed to contribute to resistance to downy mildew, a potentially devastating disease that threatens sweet corn and other similar crops. It also details the approach followed to integrate resistances for other major diseases such as southern rust (caused by Puccinia polysora Underw), Northern Corn Leaf Blight (Exserohilum turcicum) with improved agronomy and eating quality. The report explains the importance of heterosis (hybrid vigour) and combining ability in the development of useful sweet corn hybrids. It also explains the relevance of parental performance to predict its breeding value and the performance of its hybrids.

Benzyl isothiocyanate: maximising production in papaya tissue extracts

Abstract: Although mainly grown for its sweet flavoured fruit, papaya (Carica papaya) has also been used for pharmacological purposes for many years. The reasons for use are varied with one of the best known being its anti-fungal action. Benzyl isothiocyanate (BITC) is the constituent most often implicated in this activity. Isothiocyanates are formed when the enzyme myrosinase catalyses the hydrolysis of the non-bioactive glucosinolates. This occurs when cellular contents come into contact through chewing, cutting or during extraction processes in the laboratory. While this is common in Brassica vegetables, the glucosinolate-myrosinase system is rare in fruit, papaya being a notable exception. It contains benzyl glucosinolate (BG), the glucosinolate precursor of BITC, in significant quantities. Parameters that determine the amount of BITC formed are duration of hydrolysis, presence/absence of nitrile-specifier proteins and BG content of different cultivars and tissues. We experimented with differing BITC extraction solvents, with the intention of developing a low cost, natural anti-fungal extract based on under-utilised papaya tissues. The findings suggest that papaya seeds, particularly from quarter-ripe fruit, have the potential to produce the highest levels of BITC necessary. Furthermore, they compare well with the nitrile-specifier protein-containing garden cress seeds (Lepidium sativum). To utilise the papaya seeds as a BITC source, an organic solvent such as ethanol is required to extract the largely water-insoluble BITC from the hydrolysed papaya seed mixture.