The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Stanislav Trdan - One of the best experts on this subject based on the ideXlab platform.
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trap crops for reducing damage caused by Cabbage stink bugs eurydema spp and flea beetles phyllotreta spp on White Cabbage fact or fantasy
2012Co-Authors: Tanja Bohinc, Stanislav TrdanAbstract:In 2009 and 2010, a field experiment was carried out to determine the effect of three trap crops (oil radish, oil rape and White mustard) as a protection method against Cabbage stink bugs (Eurydema spp.) and flea beetles (Phyllotreta spp.) attack on two hybrids of White Cabbage. The experiment was designed as randomized complete block with four treatments. The damage caused by Cabbage stink bugs and flea beetles on the main crop and the trap crops was estimated in 10-day intervals. Oil rape was the most attractive trap crop for Cabbage stink bugs, while flea beetles displayed specific preference to oil radish as a trap crop in 2010. Flea beetles displayed specific preference for oil radish as a trap crop in 2010, while they did not display specific preference to any of trap crops tested in 2009. The damage caused by Cabbage stink bugs on Cabbage started increasing in the beginning of July. The damage caused by flea beetles, on the other hand, started increasing at the end of May. Cabbage hybrid ‘Hinova’ was more heavily attacked by both groups of the pests, mostly due to its longer growth period. The extent of damage on Cabbage and trap crops was higher in the second year, since before 2009 no Brassica crops were grown in the near vicinity of the experimental plot. The trap crop species has no important effect on the yield of Cabbage, since the pests on trap crop plants were not control with insecticides.
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yield of early White Cabbage grown under mulch and non mulch conditions with low populations of onion thrips thrips tabaci lindeman
International Journal of Pest Management, 2008Co-Authors: Stanislav Trdan, Dragan žnidarcic, Milica Kac, Matej VidrihAbstract:The damage caused by Thrips tabaci to a susceptible hybrid of early White Cabbage was studied in field experiments undertaken during 2004 and 2005. The three treatments tested were beds of Cabbage mulched with: (1) barley straw, (2) hay, and (3) black polyethylene (PE) sheeting. Bare-soil (un-mulched) beds were used as the control treatment. One early and one late experiment were performed in both years. In the early experiments, the mulches were applied at the start of the experiment, whereas in the late experiments the soil was first covered with black polyethylene for approximately 1 month. In both years, the springs were cold and wet, and so the thrips appeared late and their numbers were low. The highest mean actual weight and trimmed weight were recorded for Cabbage grown in 2005 under PE mulch (actual early: 995 g, actual late: 1184 g, trimmed early: 870 g, trimmed late: 1056 g). Year 2004 gave lower values (110g for both variables) under barley straw and hay mulch (165 g and 160 g, respectively). ...
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Field efficacy of deltamethrin in reducing damage caused by Thrips tabaci Lindeman (Thysanoptera: Thripidae) on early White Cabbage
Journal of Pest Science, 2007Co-Authors: Stanislav Trdan, Nevenka Valic, Dragan žnidarcicAbstract:Our research assessed how the number of sprayings with deltamethrin influenced the efficiency against onion thrips, Thrips tabaci , on early White Cabbage. The study was performed in 2002 and 2005 using the early White Cabbage cultivar Parel, which is very susceptible to the attack of onion thrips. The Cabbages were planted in a block-design experiment, with percentage of damage on the exterior leaves recorded according to the positions of the leaves (i.e. outer to inner). Although the attack of thrips was much greater in 2002 than in 2005, nevertheless, control plants in both years showed much more damage than plants with at least one insecticide spraying. In 2002, there was little difference between one and two sprayings, but three sprayings showed a significantly improved result. However, three sprayings of this insecticide is generally not permitted in farming practice. In 2005, no differences in efficacy among one, two and three sprayings were recorded. We also assessed a high threshold (up to 10% damaged leaf surface) and low threshold (up to 1% damaged leaf surface) for the removal of damaged leaves. In 2002, both thresholds were exceeded for control plants, but in 2005, the attack of thrips was mild enough that neither threshold was exceeded. In this case, one spraying was sufficient to reduce leaf damage below the higher (more tolerant) threshold, but three sprayings were needed to reduce leaf damage below the lower (more stringent) threshold. Therefore, in Slovenia or other parts of the world with similar climatic conditions, we recommend one spraying as broadly effective and recommend the more tolerant threshold for leaf removal.
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field efficacy of three insecticides against Cabbage stink bugs heteroptera pentatomidae on two cultivars of White Cabbage
International Journal of Pest Management, 2006Co-Authors: Stanislav Trdan, Dragan žnidarcic, Nevenka ValicAbstract:Abstract In 2002 – 2003, three insecticidal substances were tested for their ability to reduce the damage inflicted on plants of White Cabbage by Cabbage stink bugs, Eurydema ventrale and E. oleracea (Heteroptera: Pentatomidae). The two cultivars of Cabbage tested were: the early cultivar, ‘Tucana F1’, which requires about 60 days from transplanting to harvest, and the mid-early cultivar ‘Hinova F1’, which requires about 120 days. In a field experiment, the growth and damage on Cabbage plants sprayed with malathion (two sprays), potassium soap [potassium salts of fatty acids] (five sprays), and refined rape oil (five sprays) were compared to the growth and damage on unsprayed plants. Potassium soap and refined rape oil are considered to be environmentally friendly insecticides. In 2002, plants of the cultivar ‘Tucana’, that were treated with malathion had the highest plant weights [PW], head weights [HW], HW/PW ratio, and the lowest number of frame leaves. In the drier year of 2003, there were no signific...
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the role of chinese Cabbage as a trap crop for flea beetles coleoptera chrysomelidae in production of White Cabbage
Scientia Horticulturae, 2005Co-Authors: Stanislav Trdan, Nevenka Valic, Dragan žnidarcic, Matej Vidrih, Klemen Bergant, Emil Zlatic, Lea MilevojAbstract:During the years 2002 and 2003, preference of flea beetles, Phyllotreta spp., to White and Chinese Cabbage, grown in monoculture and in mixed crop, was tested. The aim of the research was to determine if Chinese Cabbage is an appropriate trap crop for this pest in the production of White Cabbage, an important vegetable in Europe and in North America. The number of beetles on Chinese Cabbage in monoculture and in mixed crop did not differ significantly. In both treatments the number of adults of flea beetles on Chinese Cabbage and the percentage of damaged leaf area they caused, were significantly higher than that on White Cabbage. Statistically significant and positive correlation was established between leaf damage and number of flea beetles. It was stronger in 2003, which was less favorable for the crop with regards to the weather conditions (drought and high air temperatures). No significant differences were found in the number of adults and in most evaluations also in the damage assessments on White Cabbage when grown in monoculture and in mixed culture. Therefore, we concluded that Chinese Cabbage grown in mixed crop with White Cabbage is not a suitable control measure for reducing the damage caused by flea beetles.
Dragan žnidarcic - One of the best experts on this subject based on the ideXlab platform.
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yield of early White Cabbage grown under mulch and non mulch conditions with low populations of onion thrips thrips tabaci lindeman
International Journal of Pest Management, 2008Co-Authors: Stanislav Trdan, Dragan žnidarcic, Milica Kac, Matej VidrihAbstract:The damage caused by Thrips tabaci to a susceptible hybrid of early White Cabbage was studied in field experiments undertaken during 2004 and 2005. The three treatments tested were beds of Cabbage mulched with: (1) barley straw, (2) hay, and (3) black polyethylene (PE) sheeting. Bare-soil (un-mulched) beds were used as the control treatment. One early and one late experiment were performed in both years. In the early experiments, the mulches were applied at the start of the experiment, whereas in the late experiments the soil was first covered with black polyethylene for approximately 1 month. In both years, the springs were cold and wet, and so the thrips appeared late and their numbers were low. The highest mean actual weight and trimmed weight were recorded for Cabbage grown in 2005 under PE mulch (actual early: 995 g, actual late: 1184 g, trimmed early: 870 g, trimmed late: 1056 g). Year 2004 gave lower values (110g for both variables) under barley straw and hay mulch (165 g and 160 g, respectively). ...
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Field efficacy of deltamethrin in reducing damage caused by Thrips tabaci Lindeman (Thysanoptera: Thripidae) on early White Cabbage
Journal of Pest Science, 2007Co-Authors: Stanislav Trdan, Nevenka Valic, Dragan žnidarcicAbstract:Our research assessed how the number of sprayings with deltamethrin influenced the efficiency against onion thrips, Thrips tabaci , on early White Cabbage. The study was performed in 2002 and 2005 using the early White Cabbage cultivar Parel, which is very susceptible to the attack of onion thrips. The Cabbages were planted in a block-design experiment, with percentage of damage on the exterior leaves recorded according to the positions of the leaves (i.e. outer to inner). Although the attack of thrips was much greater in 2002 than in 2005, nevertheless, control plants in both years showed much more damage than plants with at least one insecticide spraying. In 2002, there was little difference between one and two sprayings, but three sprayings showed a significantly improved result. However, three sprayings of this insecticide is generally not permitted in farming practice. In 2005, no differences in efficacy among one, two and three sprayings were recorded. We also assessed a high threshold (up to 10% damaged leaf surface) and low threshold (up to 1% damaged leaf surface) for the removal of damaged leaves. In 2002, both thresholds were exceeded for control plants, but in 2005, the attack of thrips was mild enough that neither threshold was exceeded. In this case, one spraying was sufficient to reduce leaf damage below the higher (more tolerant) threshold, but three sprayings were needed to reduce leaf damage below the lower (more stringent) threshold. Therefore, in Slovenia or other parts of the world with similar climatic conditions, we recommend one spraying as broadly effective and recommend the more tolerant threshold for leaf removal.
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field efficacy of three insecticides against Cabbage stink bugs heteroptera pentatomidae on two cultivars of White Cabbage
International Journal of Pest Management, 2006Co-Authors: Stanislav Trdan, Dragan žnidarcic, Nevenka ValicAbstract:Abstract In 2002 – 2003, three insecticidal substances were tested for their ability to reduce the damage inflicted on plants of White Cabbage by Cabbage stink bugs, Eurydema ventrale and E. oleracea (Heteroptera: Pentatomidae). The two cultivars of Cabbage tested were: the early cultivar, ‘Tucana F1’, which requires about 60 days from transplanting to harvest, and the mid-early cultivar ‘Hinova F1’, which requires about 120 days. In a field experiment, the growth and damage on Cabbage plants sprayed with malathion (two sprays), potassium soap [potassium salts of fatty acids] (five sprays), and refined rape oil (five sprays) were compared to the growth and damage on unsprayed plants. Potassium soap and refined rape oil are considered to be environmentally friendly insecticides. In 2002, plants of the cultivar ‘Tucana’, that were treated with malathion had the highest plant weights [PW], head weights [HW], HW/PW ratio, and the lowest number of frame leaves. In the drier year of 2003, there were no signific...
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the role of chinese Cabbage as a trap crop for flea beetles coleoptera chrysomelidae in production of White Cabbage
Scientia Horticulturae, 2005Co-Authors: Stanislav Trdan, Nevenka Valic, Dragan žnidarcic, Matej Vidrih, Klemen Bergant, Emil Zlatic, Lea MilevojAbstract:During the years 2002 and 2003, preference of flea beetles, Phyllotreta spp., to White and Chinese Cabbage, grown in monoculture and in mixed crop, was tested. The aim of the research was to determine if Chinese Cabbage is an appropriate trap crop for this pest in the production of White Cabbage, an important vegetable in Europe and in North America. The number of beetles on Chinese Cabbage in monoculture and in mixed crop did not differ significantly. In both treatments the number of adults of flea beetles on Chinese Cabbage and the percentage of damaged leaf area they caused, were significantly higher than that on White Cabbage. Statistically significant and positive correlation was established between leaf damage and number of flea beetles. It was stronger in 2003, which was less favorable for the crop with regards to the weather conditions (drought and high air temperatures). No significant differences were found in the number of adults and in most evaluations also in the damage assessments on White Cabbage when grown in monoculture and in mixed culture. Therefore, we concluded that Chinese Cabbage grown in mixed crop with White Cabbage is not a suitable control measure for reducing the damage caused by flea beetles.
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correlation between epicuticular wax content in the leaves of early White Cabbage brassica oleracea l var capitata and damage caused by thrips tabaci lindeman thysanoptera thripidae
Acta Phytopathologica Et Entomologica Hungarica, 2004Co-Authors: Stanislav Trdan, Dragan žnidarcic, Emil Zlatic, J JermanAbstract:In the period of 2001-2002 the susceptibility of five varieties of early White Cabbage to onion thrips (Thrips tabaci) attack has been studied. The variety with the longest growth period (72 days) and the firmest head (19.5-21.5 kg/cm2), i.e. Vestri, had the highest mean weight of the head (1220.0 g/head) and the highest net weight of the head (1050.6 g/head), while the mean index of damage (1.18) and the mean yield loss (13.9%) were the lowest in this variety. At higher plant density (16.6 plants/m2) both parameters of the weight of the head were approximately less than half as compared to lower plant density (8.2 plants/m2). Results of the mean net weight of the heads did not show significant differences between different plant densities if the yield was calculated per area unit (m2). The mean content of epicuticular wax differs among varieties, although all varieties show similar relations in its content; the lowest mean content in the third and the fourth exterior leaves of the head, the highest mean ...
Nevenka Valic - One of the best experts on this subject based on the ideXlab platform.
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Field efficacy of deltamethrin in reducing damage caused by Thrips tabaci Lindeman (Thysanoptera: Thripidae) on early White Cabbage
Journal of Pest Science, 2007Co-Authors: Stanislav Trdan, Nevenka Valic, Dragan žnidarcicAbstract:Our research assessed how the number of sprayings with deltamethrin influenced the efficiency against onion thrips, Thrips tabaci , on early White Cabbage. The study was performed in 2002 and 2005 using the early White Cabbage cultivar Parel, which is very susceptible to the attack of onion thrips. The Cabbages were planted in a block-design experiment, with percentage of damage on the exterior leaves recorded according to the positions of the leaves (i.e. outer to inner). Although the attack of thrips was much greater in 2002 than in 2005, nevertheless, control plants in both years showed much more damage than plants with at least one insecticide spraying. In 2002, there was little difference between one and two sprayings, but three sprayings showed a significantly improved result. However, three sprayings of this insecticide is generally not permitted in farming practice. In 2005, no differences in efficacy among one, two and three sprayings were recorded. We also assessed a high threshold (up to 10% damaged leaf surface) and low threshold (up to 1% damaged leaf surface) for the removal of damaged leaves. In 2002, both thresholds were exceeded for control plants, but in 2005, the attack of thrips was mild enough that neither threshold was exceeded. In this case, one spraying was sufficient to reduce leaf damage below the higher (more tolerant) threshold, but three sprayings were needed to reduce leaf damage below the lower (more stringent) threshold. Therefore, in Slovenia or other parts of the world with similar climatic conditions, we recommend one spraying as broadly effective and recommend the more tolerant threshold for leaf removal.
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field efficacy of three insecticides against Cabbage stink bugs heteroptera pentatomidae on two cultivars of White Cabbage
International Journal of Pest Management, 2006Co-Authors: Stanislav Trdan, Dragan žnidarcic, Nevenka ValicAbstract:Abstract In 2002 – 2003, three insecticidal substances were tested for their ability to reduce the damage inflicted on plants of White Cabbage by Cabbage stink bugs, Eurydema ventrale and E. oleracea (Heteroptera: Pentatomidae). The two cultivars of Cabbage tested were: the early cultivar, ‘Tucana F1’, which requires about 60 days from transplanting to harvest, and the mid-early cultivar ‘Hinova F1’, which requires about 120 days. In a field experiment, the growth and damage on Cabbage plants sprayed with malathion (two sprays), potassium soap [potassium salts of fatty acids] (five sprays), and refined rape oil (five sprays) were compared to the growth and damage on unsprayed plants. Potassium soap and refined rape oil are considered to be environmentally friendly insecticides. In 2002, plants of the cultivar ‘Tucana’, that were treated with malathion had the highest plant weights [PW], head weights [HW], HW/PW ratio, and the lowest number of frame leaves. In the drier year of 2003, there were no signific...
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the role of chinese Cabbage as a trap crop for flea beetles coleoptera chrysomelidae in production of White Cabbage
Scientia Horticulturae, 2005Co-Authors: Stanislav Trdan, Nevenka Valic, Dragan žnidarcic, Matej Vidrih, Klemen Bergant, Emil Zlatic, Lea MilevojAbstract:During the years 2002 and 2003, preference of flea beetles, Phyllotreta spp., to White and Chinese Cabbage, grown in monoculture and in mixed crop, was tested. The aim of the research was to determine if Chinese Cabbage is an appropriate trap crop for this pest in the production of White Cabbage, an important vegetable in Europe and in North America. The number of beetles on Chinese Cabbage in monoculture and in mixed crop did not differ significantly. In both treatments the number of adults of flea beetles on Chinese Cabbage and the percentage of damaged leaf area they caused, were significantly higher than that on White Cabbage. Statistically significant and positive correlation was established between leaf damage and number of flea beetles. It was stronger in 2003, which was less favorable for the crop with regards to the weather conditions (drought and high air temperatures). No significant differences were found in the number of adults and in most evaluations also in the damage assessments on White Cabbage when grown in monoculture and in mixed culture. Therefore, we concluded that Chinese Cabbage grown in mixed crop with White Cabbage is not a suitable control measure for reducing the damage caused by flea beetles.
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Feeding damage by onion thrips, Thrips tabaci Lindeman (Thysanoptera : Thripidae), on early White Cabbage grown under insecticide-free conditions
African Entomology, 2005Co-Authors: Stanislav Trdan, Nevenka Valic, Matej Vidrih, Klemen Bergant, Lea Milevoj, I. Zezlina, E. Raspudic, Ljiljana Andjus, D. ŽnidarčičAbstract:The effects of cultivar choice and plant density on onion thrips (Thrips tabaci) damage to early White Cabbage was studied on five varieties of early White Cabbage grown at three different densities over two years. In the drier year the Cabbage yield was smaller and greater thrips damage was recorded. The Cabbage variety 'Vestri', which had on average the firmest head, showed itself to be the most resistant to Thrips tabaci attack and gave the highest yield. The 'Parel' variety, with the shortest growing period, was the most damaged by the thrips. Most densely planted Cabbage had the lowest mean weight of heads and the lowest mean index of damage on the exterior leaves. Most of the economically important damage occurred between the third and sixth exterior leaf, although the damage extended to the fifteenth exterior leaf.
Svein Halvor Knutsen - One of the best experts on this subject based on the ideXlab platform.
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release and characterization of single side chains of White Cabbage pectin and their complement fixing activity
Molecular Nutrition & Food Research, 2009Co-Authors: Bjorge Westereng, Terje E Michaelsen, Anne Berit Samuelsen, Gerd Jan Coenen, Alphons G J Voragen, Henk A Schols, Svein Halvor KnutsenAbstract:A mixture of single side chains from White Cabbage pectin were obtained by anion exchange chromatography after applying mild chemical conditions promoting beta-elimination. These pectin fragments were characterized by their molecular weight distribution, sugar composition, 13C-NMR, and MALDI-TOF-MS analysis. These analyses revealed that the large oligosaccharides released by beta-eliminative treatment were composed of alpha-1,5 linked arabinosyl residues with 2- and 3-linked alpha-arabinosyl side chains, and, or beta-1,4 linked galactosyl side chains. Fractions were tested for complement-fixing activity in order to determine their interaction with the complement system. These results strongly indicated that there was a minimal unit size responsible for the complement-fixing activity. Neutral pectin fragments (8 kDa) obtained from beta-elimination were inactive in the complement system, although they contained a sugar composition previously shown to be highly active. Larger pectin fragments (17 kDa) retained some activity, but much lower than polymers containing rhamnogalacturonan type 1 (RGI) structures isolated from the same source. This implied that structural elements containing multiple side chains is necessary for efficient complement-fixing activity.
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effects of extraction conditions on the chemical structure and biological activity of White Cabbage pectin
Carbohydrate Polymers, 2008Co-Authors: Bjorge Westereng, Terje E Michaelsen, Anne Berit Samuelsen, Svein Halvor KnutsenAbstract:Abstract The purpose of this study was to isolate and perform chemical analyzes as well as biological testing of pectic material from White Cabbage isolated by sequential aqueous ionic solutions (SEQAIS) or a simple pure water extraction (PW). Water extraction was aimed at yielding water-soluble pectins only, while the harsher conditions in SEQAIS aimed at extracting proto pectin as well. The pectic material resulting from the various extraction steps was characterized and tested, in order to determine whether structural and biological activity were influenced through different isolation procedures. The SEQAIS fractions obtained were one water-soluble and six partly water-soluble extracts, whereas PW yielded two water-soluble extracts. Sugar composition analysis, linkage analysis, HPSEC molecular weight distribution, HPAEC and 13 C NMR were run to obtain structural characteristics of the extracted material. Both extraction procedures resulted in degradation of pectin. Pectin containing highly methyl esterified Gal p A probably underwent β-elimination due to neutral pH during PW, while hydrolysis of Ara f occurred in the first step of SEQAIS in 50 mM acetic acid pH 4.5. Water-soluble extracts were tested for complement-fixing activity and acidic extracts with degraded side chains showed reduced activity. Authors suggest that extraction conditions at neutral pH should be used in order to withhold side chain structure and immuno-activity.
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structural features and complement fixing activity of pectin from three brassica oleracea varieties White Cabbage kale and red kale
Biomacromolecules, 2007Co-Authors: Anne Berit Samuelsen, Bjorge Westereng, Osman Yousif, Terje E Michaelsen, Ann Katrin Holtekjolen, Svein Halvor KnutsenAbstract:Leaves of different Cabbage species are used both as food and as wound healing remedies in traditional medicine. This supposed wound healing activity might be connected to presence of immunomodulating water soluble polysaccharides. To study this, three different Cabbage varieties, White Cabbage (W), kale (K), and red kale (RK), were pretreated with 80% ethanol and then extracted with water at 50 °C and 100 °C for isolation of polysaccharide-containing fractions. The fractions were analyzed for monosaccharide composition, glycosidic linkages, Mw distribution, protein content, and phenolic compounds and then tested for complement-fixing activity. All fractions contained pectin type polysaccharides with linkages corresponding to homogalacturonan and hairy regions. Those extracted at 50 °C contained higher amounts of neutral side chains and were more active in the complement-fixation test than those extracted at 100 °C. The fractions can be ranged by decreasing activity: K-50 > RK-50 > W-50 ≈ K-100 > RK100 ≈...
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pectin isolated from White Cabbage structure and complement fixing activity
Molecular Nutrition & Food Research, 2006Co-Authors: Bjorge Westereng, Osman Yousif, Terje E Michaelsen, Svein Halvor Knutsen, Anne Berit SamuelsenAbstract:This study was done to investigate whether White Cabbage contained polysaccharides with immunostimulatory activity using the complement-fixing test as an indicator. The main polysaccharide isolated was of pectin nature. Methanolysis and (13)C-NMR showed that the polymers consisted of highly esterified alpha-galactopyranoside (alpha-GalpA), significant amounts of alpha-arabinose furanoside (alpha-Araf), beta-Galp and lesser amounts of rhamnose in the pyranose form (Rhap) and xylose in the pyranose form (Xylp). Linkage analyses showed that the alpha-GalpA residues were mainly 1,4-linked with small amounts of 1,3,4-linkages. The alpha-Araf residues were mainly terminally (t)- and 1,5-linked, whereas beta-Galp was t-, 1,3-, 1,6-, and 1,3,6-linked. Positive Yariv reaction indicated polymers with arabinogalactan type 2 like structures. alpha-Rhap was mainly present as 1,2- and 1,2,4-linked residues and Xylp was t- and 1,4-linked. The molecular weight varied greatly and was from 10 to 150 kDa. Cabbage polymers had biological activity and this complement-fixing activity was greatly affected by hydrolytic removal of Araf from pectic side chains.
Bjorge Westereng - One of the best experts on this subject based on the ideXlab platform.
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release and characterization of single side chains of White Cabbage pectin and their complement fixing activity
Molecular Nutrition & Food Research, 2009Co-Authors: Bjorge Westereng, Terje E Michaelsen, Anne Berit Samuelsen, Gerd Jan Coenen, Alphons G J Voragen, Henk A Schols, Svein Halvor KnutsenAbstract:A mixture of single side chains from White Cabbage pectin were obtained by anion exchange chromatography after applying mild chemical conditions promoting beta-elimination. These pectin fragments were characterized by their molecular weight distribution, sugar composition, 13C-NMR, and MALDI-TOF-MS analysis. These analyses revealed that the large oligosaccharides released by beta-eliminative treatment were composed of alpha-1,5 linked arabinosyl residues with 2- and 3-linked alpha-arabinosyl side chains, and, or beta-1,4 linked galactosyl side chains. Fractions were tested for complement-fixing activity in order to determine their interaction with the complement system. These results strongly indicated that there was a minimal unit size responsible for the complement-fixing activity. Neutral pectin fragments (8 kDa) obtained from beta-elimination were inactive in the complement system, although they contained a sugar composition previously shown to be highly active. Larger pectin fragments (17 kDa) retained some activity, but much lower than polymers containing rhamnogalacturonan type 1 (RGI) structures isolated from the same source. This implied that structural elements containing multiple side chains is necessary for efficient complement-fixing activity.
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effects of extraction conditions on the chemical structure and biological activity of White Cabbage pectin
Carbohydrate Polymers, 2008Co-Authors: Bjorge Westereng, Terje E Michaelsen, Anne Berit Samuelsen, Svein Halvor KnutsenAbstract:Abstract The purpose of this study was to isolate and perform chemical analyzes as well as biological testing of pectic material from White Cabbage isolated by sequential aqueous ionic solutions (SEQAIS) or a simple pure water extraction (PW). Water extraction was aimed at yielding water-soluble pectins only, while the harsher conditions in SEQAIS aimed at extracting proto pectin as well. The pectic material resulting from the various extraction steps was characterized and tested, in order to determine whether structural and biological activity were influenced through different isolation procedures. The SEQAIS fractions obtained were one water-soluble and six partly water-soluble extracts, whereas PW yielded two water-soluble extracts. Sugar composition analysis, linkage analysis, HPSEC molecular weight distribution, HPAEC and 13 C NMR were run to obtain structural characteristics of the extracted material. Both extraction procedures resulted in degradation of pectin. Pectin containing highly methyl esterified Gal p A probably underwent β-elimination due to neutral pH during PW, while hydrolysis of Ara f occurred in the first step of SEQAIS in 50 mM acetic acid pH 4.5. Water-soluble extracts were tested for complement-fixing activity and acidic extracts with degraded side chains showed reduced activity. Authors suggest that extraction conditions at neutral pH should be used in order to withhold side chain structure and immuno-activity.
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structural features and complement fixing activity of pectin from three brassica oleracea varieties White Cabbage kale and red kale
Biomacromolecules, 2007Co-Authors: Anne Berit Samuelsen, Bjorge Westereng, Osman Yousif, Terje E Michaelsen, Ann Katrin Holtekjolen, Svein Halvor KnutsenAbstract:Leaves of different Cabbage species are used both as food and as wound healing remedies in traditional medicine. This supposed wound healing activity might be connected to presence of immunomodulating water soluble polysaccharides. To study this, three different Cabbage varieties, White Cabbage (W), kale (K), and red kale (RK), were pretreated with 80% ethanol and then extracted with water at 50 °C and 100 °C for isolation of polysaccharide-containing fractions. The fractions were analyzed for monosaccharide composition, glycosidic linkages, Mw distribution, protein content, and phenolic compounds and then tested for complement-fixing activity. All fractions contained pectin type polysaccharides with linkages corresponding to homogalacturonan and hairy regions. Those extracted at 50 °C contained higher amounts of neutral side chains and were more active in the complement-fixation test than those extracted at 100 °C. The fractions can be ranged by decreasing activity: K-50 > RK-50 > W-50 ≈ K-100 > RK100 ≈...
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pectin isolated from White Cabbage structure and complement fixing activity
Molecular Nutrition & Food Research, 2006Co-Authors: Bjorge Westereng, Osman Yousif, Terje E Michaelsen, Svein Halvor Knutsen, Anne Berit SamuelsenAbstract:This study was done to investigate whether White Cabbage contained polysaccharides with immunostimulatory activity using the complement-fixing test as an indicator. The main polysaccharide isolated was of pectin nature. Methanolysis and (13)C-NMR showed that the polymers consisted of highly esterified alpha-galactopyranoside (alpha-GalpA), significant amounts of alpha-arabinose furanoside (alpha-Araf), beta-Galp and lesser amounts of rhamnose in the pyranose form (Rhap) and xylose in the pyranose form (Xylp). Linkage analyses showed that the alpha-GalpA residues were mainly 1,4-linked with small amounts of 1,3,4-linkages. The alpha-Araf residues were mainly terminally (t)- and 1,5-linked, whereas beta-Galp was t-, 1,3-, 1,6-, and 1,3,6-linked. Positive Yariv reaction indicated polymers with arabinogalactan type 2 like structures. alpha-Rhap was mainly present as 1,2- and 1,2,4-linked residues and Xylp was t- and 1,4-linked. The molecular weight varied greatly and was from 10 to 150 kDa. Cabbage polymers had biological activity and this complement-fixing activity was greatly affected by hydrolytic removal of Araf from pectic side chains.
