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Silanikove N.,Institute of Animal Science | Rauch-Cohen A.,Institute of Animal Science | Shapiro F.,Institute of Animal Science | Arieli A.,Hebrew University of Jerusalem | And 2 more authors.

The aim of this work was to study the effects of mastitis induced by intramammary lipopolysaccharide (LPS) challenge on milk oxidative stability, as well as to understand the underlying biochemical processes that cause such changes. LPS challenge was associated with nitric oxide burst from the surrounding mammary epithelial cells and consequently induced nitrosative stress that was induced by the formation of NO2• from nitrite by lactoperoxidase. This response was associated with an ∼3-fold increased formation of hazardous compounds: nitrotyrosines, carbonyls and lipid peroxides. We sustained the involvement of xanthine oxidase as a major source of hydrogen peroxide. In consistent with previous findings, catalase has been shown to play a major role in modulating the nitrosative stress by oxidizing nitrite to nitrate. The current hygienic quality criteria cannot detect mixing of low-quality milk, such as milk with high somatic cells, and nitrite with high-quality milk. Thus, development of an improved quality control methodology may be important for the production of high-quality milk. © The Animal Consortium 2011. Source

Edelstein M.,Newe Yaar Research Center | Tyutyunik J.,Newe Yaar Research Center | Tyutyunik J.,Hebrew University of Jerusalem | Fallik E.,Institute of Postharvest and Food science | And 3 more authors.
Scientia Horticulturae

Watermelon grafting is on the rise worldwide as an agrotechnology aimed at preventing soilborne-pest damage. Grafting watermelon on Cucurbita rootstocks may negatively affect fruit size, shape and quality. However, grafting watermelon on watermelon rootstocks can prevent these negative effects. Twenty-one exotic watermelon accessions were evaluated as potential sources for watermelon rootstock breeding programs. Most of the watermelon accessions tested in the field as rootstocks for the mini-watermelon 'Extazy' gave yields similar to the nongrafted and self-grafted 'Extazy'. Four accessions: WAN, PI 457916, PI 307750 and PI 307609, produced significantly lower yields. The accessions BDA, CON, MAL, PI 296341 and PI 307609 were selected for detailed evaluation due to their previously found tolerance to soilborne pathogens. No difference was found in the total fruit quality index between nongrafted 'Extazy' fruit and 'Extazy' fruit from plants grafted on the different watermelon accessions. Fruit weight from plants grafted on Cucurbita rootstocks was higher than that from plants grafted on 'Extazy' or on the other watermelon accessions. No bitter flavor and no cucurbitacin were present in 'Extazy' fruits of plants grafted on bitter fruit watermelon accessions. Thus the examined exotic watermelon accessions did not adversely affect fruit quality and can be used as a basic germplasm for watermelon rootstock breeding. The most promising accession is PI 296341. © 2013 Elsevier B.V. Source

Silanikove N.,Israel Agricultural Research Organization | Shapiro F.,Israel Agricultural Research Organization | Merin U.,Institute of Postharvest and Food science | Leitner G.,Kimron Veterinary Institute
Journal of Dairy Research

The aims of this study were to test the assumption that tissue-type plasminogen activator (t-PA) and plasminogen (PG) are closely associated with the casein micelle and form a functional complex that rules casein degradation. This assumption was essentially verified for bovine milk under conditions wherein the plasmin system was activated by treatment with casein hydrolysate. It was also shown that urokinase-type PA (u-PA), the second type of plasminogen activator present in milk, was not involved in casein degradation. In agreement with previous studies, we show that treatment with casein hydrolysate precipitously reduced mammary secretion, disrupted the tight junction integrity (increase in Na+ and decrease in K+ concentrations), induced hydrolysis of casein, and activated various elements of the innate and acquired immune system. In the present study, we have identified t-PA as the principal PA, which is responsible for the conversion of PG to plasmin. It was found that t-PA and plasminogen are present in freshly secreted milk (less than 10Â min from its secretion), suggesting that they are secreted as a complex by the mammary gland epithelial cells. Further research is needed to provide the direct evidence to verify this concept. Copyright © Proprietors of Journal of Dairy Research 2013. Source

Goren A.,Institute of Postharvest and Food science | Alakali-Tuvia S.,Institute of Postharvest and Food science | Perzelan Y.,Institute of Postharvest and Food science | Aharon Z.,Institute of Postharvest and Food science | And 2 more authors.
Acta Horticulturae

Colored shade nets (photo-selective nets - ChromatiNets), which have been developed during the last decade to filter selected spectral regions of sunlight, concomitantly with inducing light scattering, are designed to specifically modify plant attributes such as more fruits on the plants and higher yield. In studies conducted during the last two years on two cultivars of red sweet bell pepper (Capsicum annuum); 'Romans' and 'Vergasa', we have found that peppers grown in semi-arid region under the Pearl and Yellow shade nets, significantly maintained better fruit quality after 15 d storage at 7°C plus 3 d shelf life simulation, compared to the traditional black shade net, or the Red shade net of equivalent shading capacity (35%). Most prominently, the Pearl and Yellow nets significantly reduced decay incidence in both cultivars during the two years, compared to the Black and Red shade nets. The main decay-causing agent was Alternaria alternata. Results have shown a significant reduction in Alternaria spp. population in the field, under both Pearl and Yellow nets as evaluated by selective growing medium. Red shade net significantly reduced fruit weight loss, compared to the other shade nets, but other quality parameters such as firmness, elasticity and sugar level have not been affected by the colored shade nets. Source

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