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Sample records for sarracenia purpurea prey

  1. Proteomic characterization of the major arthropod associates of the carnivorous pitcher plant Sarracenia purpurea.

    Science.gov (United States)

    Gotelli, Nicholas J; Smith, Aidan M; Ellison, Aaron M; Ballif, Bryan A

    2011-06-01

    The array of biomolecules generated by a functioning ecosystem represents both a potential resource for sustainable harvest and a potential indicator of ecosystem health and function. The cupped leaves of the carnivorous pitcher plant, Sarracenia purpurea, harbor a dynamic food web of aquatic invertebrates in a fully functional miniature ecosystem. The energetic base of this food web consists of insect prey, which is shredded by aquatic invertebrates and decomposed by microbes. Biomolecules and metabolites produced by this food web are actively exchanged with the photosynthesizing plant. In this report, we provide the first proteomic characterization of the sacrophagid fly (Fletcherimyia fletcheri), the pitcher plant mosquito (Wyeomyia smithii), and the pitcher-plant midge (Metriocnemus knabi). These three arthropods act as predators, filter feeders, and shredders at distinct trophic levels within the S. purpurea food web. More than 50 proteins from each species were identified, ten of which were predominantly or uniquely found in one species. Furthermore, 19 peptides unique to one of the three species were identified using an assembled database of 100 metazoan myosin heavy chain orthologs. These molecular signatures may be useful in species monitoring within heterogeneous ecosystem biomass and may also serve as indicators of ecosystem state.

  2. Effects of a ciliate protozoa predator on microbial communities in pitcher plant (Sarracenia purpurea leaves.

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    Taylor K Paisie

    Full Text Available The aquatic communities found within the water filled leaves of the pitcher plant, Sarracenia purpurea, have a simple trophic structure providing an ideal system to study microscale interactions between protozoan predators and their bacterial prey. In this study, replicate communities were maintained with and without the presence of the bactivorous protozoan, Colpoda steinii, to determine the effects of grazing on microbial communities. Changes in microbial (Archaea and Bacteria community structure were assessed using iTag sequencing of 16S rRNA genes. The microbial communities were similar with and without the protozoan predator, with>1000 species. Of these species, Archaea were negligible, with Bacteria comprising 99.99% of the microbial community. The Proteobacteria and Bacteroidetes were the most dominant phyla. The addition of a protozoan predator did not have a significant effect on microbial evenness nor richness. However, the presence of the protozoan did cause a significant shift in the relative abundances of a number of bacterial species. This suggested that bactivorous protozoan may target specific bacterial species and/or that certain bacterial species have innate mechanisms by which they evade predators. These findings help to elucidate the effect that trophic structure perturbations have on predator prey interactions in microbial systems.

  3. Fungal endophyte diversity in Sarracenia

    Science.gov (United States)

    Fungal endophytes were isolated from four species of the carnivorous pitcher plant genus Sarracenia: S. minor, S. oreophila, S. purpurea, and S. psittacina. Twelve taxa of fungi, eight within the Ascomycota and four within the Basidiomycota, were identified based on PCR amplification and sequencing ...

  4. Occurrence and growth characteristics of Escherichia coli and enterococci within the accumulated fluid of the northern pitcher plant (Sarracenia purpurea L.)

    Science.gov (United States)

    Whitman, Richard L.; Byers, Stacey E.; Shively, Dawn A.; Ferguson, Donna M.; Byappanahalli, Muruleedhara N.

    2005-01-01

    Sarracenia purpurea L., a carnivorous bog plant (also known as the pitcher plant), represents an excellent model of a well-defined, self-contained ecosystem; the individual pitchers of the plant serve as a microhabitat for a variety of micro- and macro-organisms. Previously, fecal indicator bacteria (Escherichia coli and enterococci) were shown as incidental contaminants in pitcher fluid; however, whether their occurrence in pitcher fluid is incidental or common has not been established. The purpose of this study was to investigate the occurrence, distribution, and growth potential of E. coli and enterococci in pitcher plant fluid from a protected bog in northwest Indiana. Escherichia coli and enterococci were recovered in pitcher fluids (n = 43 plants), with mean densities (log CFU mL-1) of 1.28 ± 0.23 and 1.97 ± 0.27, respectively. In vitro experiments showed that E. coli growth in fluid not containing insects or indigenous organisms was directly proportional to the fluid concentration (growth was 10-fold in 24 h in 100% fluid); however, in the presence of other indigenous organisms, E. coli and enterococci were only sustained for 5 days at 26 °C. Pulsed-field gel electrophoresis (PFGE) analysis showed that the plant Enterococcus faecalis isolates were genetically distinct from the human isolates; identical PFGE patterns were observed among plant isolates that fell into one of six clonal groups. These findings suggest that (i) E. coli and enterococci occurrence in pitcher plants is rather common in the bog studied, although their originating source is unclear, and (ii) the pitcher fluid contains adequate nutrients, especially carbon and energy sources, to promote the growth of indicator bacteria; however, under natural conditions, the biotic factors (e.g., competition for nutrients) may restrict their growth.

  5. Mismatch in microbial food webs: predators but not prey perform better in their local biotic and abiotic conditions.

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    Parain, Elodie C; Gravel, Dominique; Rohr, Rudolf P; Bersier, Louis-Félix; Gray, Sarah M

    2016-07-01

    Understanding how trophic levels respond to changes in abiotic and biotic conditions is key for predicting how food webs will react to environmental perturbations. Different trophic levels may respond disproportionately to change, with lower levels more likely to react faster, as they typically consist of smaller-bodied species with higher reproductive rates. This response could cause a mismatch between trophic levels, in which predators and prey will respond differently to changing abiotic or biotic conditions. This mismatch between trophic levels could result in altered top-down and bottom-up control and changes in interaction strength. To determine the possibility of a mismatch, we conducted a reciprocal-transplant experiment involving Sarracenia purpurea food webs consisting of bacterial communities as prey and a subset of six morphologically similar protozoans as predators. We used a factorial design with four temperatures, four bacteria and protozoan biogeographic origins, replicated four times. This design allowed us to determine how predator and prey dynamics were altered by abiotic (temperature) conditions and biotic (predators paired with prey from either their local or non-local biogeographic origin) conditions. We found that prey reached higher densities in warmer temperature regardless of their temperature of origin. Conversely, predators achieved higher densities in the temperature condition and with the prey from their origin. These results confirm that predators perform better in abiotic and biotic conditions of their origin while their prey do not. This mismatch between trophic levels may be especially significant under climate change, potentially disrupting ecosystem functioning by disproportionately affecting top-down and bottom-up control.

  6. Metabolite profiling of the carnivorous pitcher plants Darlingtonia and Sarracenia

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    Seppänen-Laakso, Tuulikki

    2017-01-01

    Sarraceniaceae is a New World carnivorous plant family comprising three genera: Darlingtonia, Heliamphora, and Sarracenia. The plants occur in nutrient-poor environments and have developed insectivorous capability in order to supplement their nutrient uptake. Sarracenia flava contains the alkaloid coniine, otherwise only found in Conium maculatum, in which its biosynthesis has been studied, and several Aloe species. Its ecological role and biosynthetic origin in S. flava is speculative. The aim of the current research was to investigate the occurrence of coniine in Sarracenia and Darlingtonia and to identify common constituents of both genera, unique compounds for individual variants and floral scent chemicals. In this comprehensive metabolic profiling study, we looked for compound patterns that are associated with the taxonomy of Sarracenia species. In total, 57 different Sarracenia and D. californica accessions were used for metabolite content screening by gas chromatography-mass spectrometry. The resulting high-dimensional data were studied using a data mining approach. The two genera are characterized by a large number of metabolites and huge chemical diversity between different species. By applying feature selection for clustering and by integrating new biochemical data with existing phylogenetic data, we were able to demonstrate that the chemical composition of the species can be explained by their known classification. Although transcriptome analysis did not reveal a candidate gene for coniine biosynthesis, the use of a sensitive selected ion monitoring method enabled the detection of coniine in eight Sarracenia species, showing that it is more widespread in this genus than previously believed. PMID:28222171

  7. Fluorescent prey traps in carnivorous plants.

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    Kurup, R; Johnson, A J; Sankar, S; Hussain, A A; Sathish Kumar, C; Sabulal, B

    2013-05-01

    Carnivorous plants acquire most of their nutrients by capturing ants, insects and other arthropods through their leaf-evolved biological traps. So far, the best-known attractants in carnivorous prey traps are nectar, colour and olfactory cues. Here, fresh prey traps of 14 Nepenthes, five Sarracenia, five Drosera, two Pinguicula species/hybrids, Dionaea muscipula and Utricularia stellaris were scanned at UV 366 nm. Fluorescence emissions of major isolates of fresh Nepenthes khasiana pitcher peristomes were recorded at an excitation wavelength of 366 nm. N. khasiana field pitcher peristomes were masked by its slippery zone extract, and prey capture rates were compared with control pitchers. We found the existence of distinct blue fluorescence emissions at the capture spots of Nepenthes, Sarracenia and Dionaea prey traps at UV 366 nm. These alluring blue emissions gradually developed with the growth of the prey traps and diminished towards their death. On excitation at 366 nm, N. khasiana peristome 3:1 CHCl3–MeOH extract and its two major blue bands showed strong fluorescence emissions at 430–480 nm. Masking of blue emissions on peristomes drastically reduced prey capture in N. khasiana pitchers. We propose these molecular emissions as a critical factor attracting arthropods and other visitors to these carnivorous traps. Drosera, Pinguicula and Utricularia prey traps showed only red chlorophyll emissions at 366 nm.

  8. Chemical constituents of Tephrosia purpurea.

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    Khalafalah, Ali K; Yousef, Afifi H; Esmail, Abeer M; Abdelrazik, Mohamed H; Hegazy, Mohamed E F; Mohamed, Abou-El-Hamd H

    2010-03-01

    In continuation of our chemical investigation on some medicinal plants of the genus Tephrosia, reinvestigation of the methylenechloride/methanol (1:1) extract of the aerial parts of Tephrosia purpurea yielded an aromatic ester 1, a sesquiterpene 2 and prenylated flavonoid 3. The structures of the compounds were established by comprehensive NMR studies, including DEPT, COSY, NOE, HMQC, HMBC, EIMS and CIMS.

  9. Chemical constituents of Tephrosia purpurea

    OpenAIRE

    Khalafalah, Ali K.; Yousef, Afifi H.; Abeer M Esmail; Abdelrazik, Mohamed H.; Hegazy, Mohamed E. F.; Abou-El-Hamd H Mohamed

    2010-01-01

    In continuation of our chemical investigation on some medicinal plants of the genus Tephrosia, reinvestigation of the methylenechloride/methanol (1:1) extract of the aerial parts of Tephrosia purpurea yielded an aromatic ester 1, a sesquiterpene 2 and prenylated flavonoid 3. The structures of the compounds were established by comprehensive NMR studies, including DEPT, COSY, NOE, HMQC, HMBC, EIMS and CIMS.

  10. [Study on Salt Tolerance of Echinacea purpurea].

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    Wang, Tao; Jia, Xiao-dong; Liu, Yong-zhi; Xuan, Ji-ping; Guo, Zhong-ren; Qiao, Yu-shan

    2015-12-01

    To explore the salt tolerance of Echiancea purpurea and its mechanism. Echiancea purpurea was used as test material in this study and six salinity levels (0, 30, 60, 90, 120 and 150 mmol/L NaCl) were set. Effects on seed germination and salt tolerance relevant physiological and biochemical indexes of Echiancea purpurea were studied. Salt stress suppressed the germination of Echiancea purpurea seeds, induced osmotic adjustment substances proline, soluble sugar and K+ to increase, and activities of POD and SOD to rise, and meanwhile resulted in accumulation of Na+ and decrease of K+/Na+. Echiancea purpurea can tolerant salt stress to a certain degree, but in case of high salt concentrations, severe salt injury would remarkably suppress the growth of Echinacea purpurea.

  11. Chemical constituents of Tephrosia purpurea

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    Ali K Khalafalah

    2010-01-01

    Full Text Available In continuation of our chemical investigation on some medicinal plants of the genus Tephrosia, reinvestigation of the methylenechloride/methanol (1:1 extract of the aerial parts of Tephrosia purpurea yielded an aromatic ester 1, a sesquiterpene 2 and prenylated flavonoid 3. The structures of the compounds were established by comprehensive NMR studies, including DEPT, COSY, NOE, HMQC, HMBC, EIMS and CIMS.

  12. Ethnopharmacology, phytochemistry and pharmacology of Tephrosia purpurea.

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    Palbag, Satadru; Dey, Bijay Kr; Singh, Narendra Kumar

    2014-01-01

    Tephrosia purpurea (L.) Pers. is popularly known as 'Sarapunkha' in classical Ayurvedic texts. It is a perennial plant belonging to the family Fabaceae, and occurs throughout the Indian subcontinent. T. purpurea is traditionally used to treat splenomegaly, cirrhosis, cough and cold, abdominal swelling and as an antidote in the Ayurvedic system of medicine. Phytochemical investigations indicate the presence of semiglabrin, pongamole, lanceolatins A and B, rutin, lupeol, and β-sitosterol. Flavonoids including (+)-tephrorin A and B, (+)-tephrosone, an isoflavone, 7, 4'-dihydroxy-3', 5'-dimethoxyisoflavone and a chalcone, (+)-tephropurpurin were isolated from the whole plant. Pharmacological activities of different parts of the plant reported include anti-inflammatory, antiulcer, antimicrobial, antioxidant, antiallergic, antidiabetic, hepatoprotective, antitumor and insect repellent activity. In the present review, the literature on the phytochemical and pharmacological investigations of Tephrosia purpurea (L.) Pers. are summarized to August, 2012.

  13. Ardea purpurea madagascariensis, nov. subsp. from Madagascar

    NARCIS (Netherlands)

    Oort, van E.D.

    1910-01-01

    The purple heron of Madagascar is a much darker bird than Ardea purpurea L. of Europe and Africa. The fore part of the throat and the neck are streaked with black like in this species, but the black streaks are broader and more numerous. The black lines, running down each side of the neck are much b

  14. Two New Secondary Metabolites from Tephrosia purpurea.

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    Chen, Yin-Ning; Peng, Yan; Gao, Cheng-Hai; Yan, Tao; Xu, Zhi-Fang; Qius, Samuel X; Cao, Wen-Hao; Deng, Ligao; Huang, Ri-Ming

    2015-06-01

    Further investigation of Tephrosia purpurea led to the isolation of a new prenylated flavone, isoglabratephrin B (1) and a new 1,2-ethanedione benzofuran derivative, purpdione B (2). The structures of the new isolates were elucidated on the basis of extensive spectroscopic analysis.

  15. Rare prenylated flavonoids from Tephrosia purpurea.

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    Hegazy, Mohamed-Elamir F; Abd el-Razek, Mohamed H; Nagashima, Fumihiro; Asakawa, Yoshinori; Paré, Paul W

    2009-01-01

    Chemical investigations of aerial parts of Tephrosia purpurea yielded the rare prenylated flavonoids, tephropurpulin A (1) and isoglabratephrin (2), in addition to a previously identified flavonoid, glabratephrin (3). Structures were established by 1D and 2D NMR spectroscopy, as well as by HR-MS analysis; for compounds 2 and 3, structures were confirmed by X-ray analysis.

  16. The effect of Echinacea purpurea on the pharmacokinetics of docetaxel.

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    Goey, Andrew K L; Meijerman, Irma; Rosing, Hilde; Burgers, Jacobus A; Mergui-Roelvink, Marja; Keessen, Marianne; Marchetti, Serena; Beijnen, Jos H; Schellens, Jan H M

    2013-09-01

    The herbal medicine Echinacea purpurea (E. purpurea) has been shown to induce cytochrome P450 3A4 (CYP3A4) both in vitro and in humans. This study explored whether E. purpurea affects the pharmacokinetics of the CYP3A4 substrate docetaxel in cancer patients. Ten evaluable cancer patients received docetaxel (135 mg, 60 min IV infusion) before intake of a commercially available E. purpurea extract (20 oral drops three times daily) and 3 weeks later after a 14 day supplementation period with E. purpurea. In both cycles, pharmacokinetic parameters of docetaxel were determined. Before and after supplementation with E. purpurea, the mean area under the plasma concentration-time curve of docetaxel was 3278 ± 1086 and 3480 ± 1285 ng ml(-1) h, respectively. This result was statistically not significant. Nonsignificant alterations were also observed for the elimination half-life (from 30.8 ± 19.7 to 25.6 ± 5.9 h, P = 0.56) and maximum plasma concentration of docetaxel (from 2224 ± 609 to 2097 ± 925 ng ml(-1) , P = 0.30). The multiple treatment of E. purpurea did not significantly alter the pharmacokinetics of docetaxel in this study. The applied E. purpurea product at the recommended dose may be combined safely with docetaxel in cancer patients. © 2013 The British Pharmacological Society.

  17. Echinacea purpurea: Pharmacology, phytochemistry and analysis methods

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    Azadeh Manayi

    2015-01-01

    Full Text Available Echinacea purpurea (Asteraceae is a perennial medicinal herb with important immunostimulatory and anti-inflammatory properties, especially the alleviation of cold symptoms. The plant also attracted scientists′ attention to assess other aspects of its beneficial effects. For instance, antianxiety, antidepression, cytotoxicity, and antimutagenicity as induced by the plant have been revealed in various studies. The findings of the clinical trials are controversial in terms of side effects. While some studies revealed the beneficial effects of the plant on the patients and no severe adverse effects, some others have reported serious side effects including abdominal pain, angioedema, dyspnea, nausea, pruritus, rash, erythema, and urticaria. Other biological activities of the plant such as antioxidant, antibacterial, antiviral, and larvicidal activities have been reported in previous experimental studies. Different classes of secondary metabolites of the plant such as alkamides, caffeic acid derivatives, polysaccharides, and glycoproteins are believed to be biologically and pharmacologically active. Actually, concurrent determination and single analysis of cichoric acid and alkamides have been successfully developed mainly by using high-performance liquid chromatography (HPLC coupled with different detectors including UV spectrophotometric, coulometric electrochemical, and electrospray ionization mass spectrometric detectors. The results of the studies which were controversial revealed that in spite of major experiments successfully accomplished using E. purpurea, many questions remain unanswered and future investigations may aim for complete recognition of the plant′s mechanism of action using new, complementary methods.

  18. Echinacea purpurea: Pharmacology, phytochemistry and analysis methods.

    Science.gov (United States)

    Manayi, Azadeh; Vazirian, Mahdi; Saeidnia, Soodabeh

    2015-01-01

    Echinacea purpurea (Asteraceae) is a perennial medicinal herb with important immunostimulatory and anti-inflammatory properties, especially the alleviation of cold symptoms. The plant also attracted scientists' attention to assess other aspects of its beneficial effects. For instance, antianxiety, antidepression, cytotoxicity, and antimutagenicity as induced by the plant have been revealed in various studies. The findings of the clinical trials are controversial in terms of side effects. While some studies revealed the beneficial effects of the plant on the patients and no severe adverse effects, some others have reported serious side effects including abdominal pain, angioedema, dyspnea, nausea, pruritus, rash, erythema, and urticaria. Other biological activities of the plant such as antioxidant, antibacterial, antiviral, and larvicidal activities have been reported in previous experimental studies. Different classes of secondary metabolites of the plant such as alkamides, caffeic acid derivatives, polysaccharides, and glycoproteins are believed to be biologically and pharmacologically active. Actually, concurrent determination and single analysis of cichoric acid and alkamides have been successfully developed mainly by using high-performance liquid chromatography (HPLC) coupled with different detectors including UV spectrophotometric, coulometric electrochemical, and electrospray ionization mass spectrometric detectors. The results of the studies which were controversial revealed that in spite of major experiments successfully accomplished using E. purpurea, many questions remain unanswered and future investigations may aim for complete recognition of the plant's mechanism of action using new, complementary methods.

  19. New bromotyrosine alkaloids from the marine sponge Psammaplysilla purpurea

    Digital Repository Service at National Institute of Oceanography (India)

    Tilvi, S.; Rodrigues, C; Naik, C; Parameswaran, P.S.; Wahidullah, S.

    Seven new bromotyrosine alkaloids Purpurealidin A, B, C, D, F, G, H and the known compounds Purealidin Q, Purpurealidin E, 16-Debromoaplysamine-4 and Purpuramine I have been isolated from the marine sponge Psammaplysilla purpurea. Their structure...

  20. FEATURES OF PONDS ECOSYSTEM WHEN ECHINACEA PURPUREA (ECHINACEA PURPUREA L. MOENCH WERE USING IN CARP FEEDING

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    G. Dobrjanska

    2013-09-01

    Full Text Available Purpose. Definition fish productivity of the experimental ponds, fixed set of chemical parameters, that are specific to the environmental condition of water, which is the process of growing fish in a certain relation to it, and the level of accumulation of heavy metals in different organs and tissues of carp. Methodology. The ponds was three breed groups one-years carp average weight 39,7 g (hybrid of carp and wild carp, crossbreed frames carp, lyubin scaly carp with planting density 1000 ind./ha. Control group of carp was fed extruded feed containing 20 % protein, and research group ― the same feed, which was added in the manufacturing process, chopped dried Echinacea purpurea in the amount of 1 %. The duration of the experiment was 86 days. Definition of hydro-chemical parameters was performed by standard methods in analytical chemistry. Quantitative determination of the concentration of heavy metals in water and the organs and tissues of fish was performed by direct absorption solution in propane-butane air flames using absorption spectrophotometer C-115-M1. Findings. It was reviewed ecological status of water bodies. Found that when used in feeding carp Echinacea purpurea increased fish productivity, reduced cost of feed for growing. Chemical composition of experimental ponds water, while virtually unchanged. The comparative characteristics of heavy metals in organs and tissues carp in this part of the diet. Originality. At first time investigated the influence of Echinacea purpurea by adding it to feed on fish productivity, accumulation and distribution of heavy metals in organs and tissues of carp. Practical value. Fish productivity in the experimental ponds was higher by 20,4 % relative to control. Costs of feed per pound of gain decreased by 13,3 % when was used in fish feeding chopped dried Echinacea purpurea. Almost all metals accumulated in the organs and tissues of experimental groups of carp in a somewhat lesser extent.

  1. Domestication of a Mesoamerican cultivated fruit tree, Spondias purpurea.

    Science.gov (United States)

    Miller, Allison; Schaal, Barbara

    2005-09-01

    Contemporary patterns of genetic variation in crops reflect historical processes associated with domestication, such as the geographic origin(s) of cultivated populations. Although significant progress has been made in identifying several global centers of domestication, few studies have addressed the issue of multiple origins of cultivated plant populations from different geographic regions within a domestication center. This study investigates the domestication history of jocote (Spondias purpurea), a Mesoamerican cultivated fruit tree. Sequences of the chloroplast spacer trnG-trnS were obtained for cultivated and wild S. purpurea trees, two sympatric taxa (Spondias mombin var. mombin and Spondias radlkoferi), and two outgroups (S. mombin var. globosa and Spondias testudinus). A phylogeographic approach was used and statistically significant associations of clades and geographical location were tested with a nested clade analysis. The sequences confirm that wild populations of S. purpurea are the likely progenitors of cultivated jocote trees. This study provides phylogeographic evidence of multiple domestications of this Mesoamerican cultivated fruit tree. Haplotypes detected in S. purpurea trees form two clusters, each of which includes alleles recovered in both cultivated and wild populations from distinct geographic regions. Cultivated S. purpurea populations have fewer unique trnG-trnS alleles than wild populations; however, five haplotypes were absent in the wild. The presence of unique alleles in cultivation may reflect contemporary extinction of the tropical dry forests of Mesoamerica. These data indicate that some agricultural habitats may be functioning as reservoirs of genetic variation in S. purpurea.

  2. Skin improvement and stability of Echinacea purpurea dermatological formulations.

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    Yotsawimonwat, S; Rattanadechsakul, J; Rattanadechsakul, P; Okonogi, S

    2010-10-01

    Echinacea purpurea contains many beneficial constituents for protection of skin from oxidative stress and for improving hydration of skin. This study aimed to investigate the stability and dermatological efficacy of E. purpurea cream and gel. Echinacea purpurea extract was incorporated into suitable cream and gel bases. Stability of the extract in the formulations was investigated by determining its residual total phenolic content and antioxidant activity after storage at 4°C, 30°C and 40°C for 6 months. The effect of those formulations on skin irritation, hydration level and wrinkle reduction was evaluated in 10 healthy volunteers, aged 25-40 years. The shelf lives of E. purpurea cream and gel in terms of total phenolic content and antioxidant activity were only 2 and 4 months respectively at 4°C and could be extended up to 7 months by incorporation of α-tocopherol or disodium editate. The corneometer hydration indices increased up to 10.6 AU and 11.4 AU, and the wrinkles decreased 9.47% and 14.92% because of the application of E. purpurea cream and gel for 1 month. Both formulations showed no irritation to skin. Echinacea purpurea cream and gel developed in this study were effective in improving skin hydration and reducing wrinkle, but showed low storage stability.

  3. Ecoepidemic predator-prey model with feeding satiation, prey herd behavior and abandoned infected prey

    NARCIS (Netherlands)

    Kooi, B.W.; Venturino, E.

    2016-01-01

    In this paper we analyse a predator–prey model where the prey population shows group defense and the prey individuals are affected by a transmissible disease. The resulting model is of the Rosenzweig–MacArthur predator–prey type with an SI (susceptible-infected) disease in the prey. Modeling prey gr

  4. Ecoepidemic predator-prey model with feeding satiation, prey herd behavior and abandoned infected prey

    NARCIS (Netherlands)

    Kooi, B.W.; Venturino, E.

    2016-01-01

    In this paper we analyse a predator–prey model where the prey population shows group defense and the prey individuals are affected by a transmissible disease. The resulting model is of the Rosenzweig–MacArthur predator–prey type with an SI (susceptible-infected) disease in the prey. Modeling prey

  5. Cytotoxic compounds from endemic Arnebia purpurea.

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    Yuzbasioglu, Merve; Kuruuzum-Uz, Ayse; Guvenalp, Zuhal; Simon, András; Tóth, Gabór; Harput, U Sebnem; Kazaz, Cavit; Bilgili, Bilgehan; Duman, Hayri; Saracoglu, Iclal; Demirezer, L Omur

    2015-04-01

    Phytochemical studies of the roots and aerial parts of endemic Arnebia purpurea S. Erik & H. Sumbul resulted in the isolation and characterization of four naphthoquinones [isovalerylalkannin (1), α-methyl-n-butanoyl alkannin (2), acetylalkannin (3), and alkannin (4)], a triterpene derivative [3-O-acetyl-oleanolic acid (5)], a steroid [β-sitosterol (6)], three flavonoid glycosides [isorhamnetin-3-O-rutinoside (7), kaempferol-3-O-rutinoside (8), kaempferol 3-O-(5"-acetyl) apiofuranoside 7-O-rhamnopyranoside (9)] and a phenolic acid [rosmarinic acid (10)]. 3-O-Acetyl-oleanolic acid, isorhamnetin-3-O-rutinoside, kaempferol-3-O-mrutinoside, and kaempferol 3-O-(5"-acetyl) apiofuranoside 7-O-rhamnopyranoside are reported from an Arnebia species for the first time. Cytotoxic activities on L929 murine fibrosarcoma cell line of the isolated compounds were investigated using MTT assay. Naphthoquinones (1-4) showed intermediate cytotoxic activity in comparison with the standard, doxorubicin.

  6. UPAYA PENGAKARAN Echinacea purpurea L DENGAN AUKSIN SECARA KULTUR JARINGAN

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    Heru Sudrajat

    2013-03-01

    Full Text Available Recently, to meet the needs of botanicals medicinal plants the cultivation directed, require good quality and uniform seeds on form and time.    Tissue culture research to from root of Echinacea purpurea L by the provision of IBA and NAA will be conducted.This recearched aimed to develop an and cultivate qualified Echinacea purpurea L as the raw material for drug foemulation. Tissue culture techniques has  more advantage because it is not affected by the climate, relatively fast production, free contamination of microbial and do not require large tracts of land. The research was carried out considering the need to be developed and cultivated plant Echinacea purpurea L qualified as raw material for the drug tissue culture techniques has advantages because it is not affected by the climate with relatively fast production time, free of microbial contamination and do not require large tracts of land. Shoots multipication done on MS medium using growth regulators GA3with concentration of 3 mg / l. Research foor rof induction on Echinacea purpurea L shoot made by adding growth regulators of IBA and NAA with concentrations with 0, 2, 4 and 6 mg / l respectively. The 2 months incubation periods produced tehe best root induction on the additon of IBA 4 mg / l. It producted 16 roots with a length of 4 cm and relatively lagre in size.Keywords: Echinacea purpurea L., tissue culture, IBA, NAA, plant growth regulators

  7. Evaluation of antiinflammatory activity ofTephrosia purpurea in rats

    Institute of Scientific and Technical Information of China (English)

    Shenoy Smita; Shwetha K; Prabhu K; Maradi R; Bairy KL; Shanbhag T

    2010-01-01

    Objective:To evaluate the antiinflammatory activity of orally administered ethanolic extract of Tephrosia purpurea in acute and subacute inflammation in rats.Methods: An ethanolic extract of Tephrosia purpurea was prepared. Carrageenan induced paw edema and cotton pellet granuloma were the models for acute and subacute inflammation respectively. Four groups of rats in each model were treated orally with 2% gum acacia, 100 mg /kg of aspirin, 500 mg/kg and 1 000 mg/kg of ethanolic extract ofTephrosia purpurea respectively. In carrageenan induced paw edema model, subplantar injection of 1% carrageenan was made into the hind paw of the rats sixty minutes after the administration of the respective drugs. The paw volume was measured immediately after injection of carrageenan, at 3 hours and at 6 hours. Then percentage inhibition of edema was calculated. In the cotton pellet granuloma model, animals were administered drugs for six days after placing cotton pellets in the axilla on each side. On the 7th day, dry weight of granuloma was calculated.Results:The rats treated withTephrosia purpurea did not exhibit any significant decrease in paw volume and serum ceruloplasmin levels as compared to the control and aspirin treated groups in the acute inflammation model; while, there was a significant (P < 0.01) decrease in the weight of granuloma inTephrosia purpurea and aspirin treated groups as compared to control in subacute inflammation.Conclusions:The ethanolic extract of orally administered Tephrosia purpurea shows significant antiinflammatory effect in subacute inflammation but not in acute inflammation in rats.

  8. Purple Pitcher Plant (Sarracenia rosea) Dieback and Partial Community Disassembly following Experimental Storm Surge in a Coastal Pitcher Plant Bog

    Science.gov (United States)

    Abbott, Matthew J.; Battaglia, Loretta L.

    2015-01-01

    Sea-level rise and frequent intense hurricanes associated with climate change will result in recurrent flooding of inland systems such as Gulf Coastal pitcher plant bogs by storm surges. These surges can transport salt water and sediment to freshwater bogs, greatly affecting their biological integrity. Purple pitcher plants (Sarracenia rosea) are Gulf Coast pitcher plant bog inhabitants that could be at a disadvantage under this scenario because their pitcher morphology may leave them prone to collection of saline water and sediment after a surge. We investigated the effects of storm surge water salinity and sediment type on S. rosea vitality, plant community structure, and bog soil-water conductivity. Plots (containing ≥1 ramet of S. rosea) were experimentally flooded with fresh or saline water crossed with one of three sediment types (local, foreign, or no sediment). There were no treatment effects on soil-water conductivity; nevertheless, direct exposure to saline water resulted in significantly lower S. rosea cover until the following season when a prescribed fire and regional drought contributed to the decline of all the S. rosea to near zero percent cover. There were also significant differences in plant community structure between treatments over time, reflecting how numerous species increased in abundance and a few species decreased in abundance. However, in contrast to S. rosea, most of the other species in the community appeared resilient to the effects of storm surge. Thus, although the community may be somewhat affected by storm surge, those few species that are particularly sensitive to the storm surge disturbance will likely drop out of the community and be replaced by more resilient species. Depending on the longevity of these biological legacies, Gulf Coastal pitcher plant bogs may be incapable of fully recovering if they become exposed to storm surge more frequently due to climate change. PMID:25874369

  9. A single predator multiple prey model with prey mutation

    Science.gov (United States)

    Mullan, Rory; Abernethy, Gavin M.; Glass, David H.; McCartney, Mark

    2016-11-01

    A multiple species predator-prey model is expanded with the introduction of a coupled map lattice for the prey, allowing the prey to mutate discretely into other prey species. The model is examined in its single predator, multiple mutating prey form. Two unimodal maps are used for the underlying dynamics of the prey species, with different predation strategies being used. Conclusions are drawn on how varying the control parameters of the model governs the overall behaviour and survival of the species. It is observed that in such a complex system, with multiple mutating prey, a large range of non-linear dynamics is possible.

  10. Investigation of phenolic constituents in Echinacea purpurea grown in China.

    Science.gov (United States)

    Liu, Yi-Chen; Zeng, Jian-Guo; Chen, Bo; Yao, Shou-Zhou

    2007-12-01

    Echinacea is a North American native medicinal herb. In 1990 s, it was introduced in China. Nowadays, Echinacea is growing successfully in a number of places in China, and has been used as a crude drug. However, the phytochemical variation in the plant grown in China has not been studied. In this study, the contents of total phenolics and caffeic acid derivatives in aerial parts and roots of Echinacea purpurea grown in China were investigated by high-performance liquid chromatography (HPLC) and colorimetric analysis. The effects of different drying methods on the components were also studied. The results show that the content of caffeic acid derivatives in E. purpurea reached its highest in the middle stage of full blossoming. The content of caffeic acid derivatives in fresh raw material was generally higher than that in dried raw material. There was no significant difference in the content of caffeic acid derivatives among three geographical populations of E. purpurea. Furthermore, the developmental pattern of total phenolics in E. purpurea was the same as that of caffeic acid derivatives. The stage of mid-bloom is an optimal harvesting period for both caffeic acid derivatives and total phenolics. In addition, the results show that the fresh raw material is the optimal material for pharmaceutical purposes, and that the optimal pharmaceutical parts are the roots, leaves and flowers.

  11. Echinacea purpurea extracts modulate murine dendritic cell fate and function.

    Science.gov (United States)

    Benson, Jenna M; Pokorny, Amanda J; Rhule, Ava; Wenner, Cynthia A; Kandhi, Vamsikrishna; Cech, Nadja B; Shepherd, David M

    2010-05-01

    Echinacea is a top-selling herbal remedy that purportedly acts as an immunostimulant. However, the specific immunomodulatory effects of Echinacea remain to be elucidated. We focused on defining the effects of Echinacea purpurea extracts in dendritic cells (DCs), which generate innate and adaptive immune responses. We hypothesized that E. purpurea extracts would enhance murine bone marrow-derived DC (BMDC) activation leading to increased immune responses. The fate and function of DCs from C57Bl/6 mice was evaluated following 48h exposure to E. purpurea root and leaf extracts. Flow cytometry revealed that the polysaccharide-rich root extract increased the expression of MHC class II, CD86, and CD54 surface biomarkers whereas the alkylamide-rich leaf extract inhibited expression of these molecules. Production of IL-6 and TNF-alpha increased in a concentration-dependent manner with exposure to the root, but not leaf, extract. In contrast, the leaf but not root extract inhibited the enzymatic activity of cyclooxygenase-2. While both extracts decreased the uptake of ovalbumin by BMDCs, the leaf but not root extract inhibited the antigen-specific activation of naïve CD4(+) T cells from OT II/Thy1.1 mice. Collectively, these results suggest that E. purpurea can be immunostimulatory, immunosuppressive, and/or anti-inflammatory depending on the portion of the plant and extraction method. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  12. L-shaped prey isocline in the Gause predator-prey experiments with a prey refuge.

    Science.gov (United States)

    Křivan, Vlastimil; Priyadarshi, Anupam

    2015-04-01

    Predator and prey isoclines are estimated from data on yeast-protist population dynamics (Gause et al., 1936). Regression analysis shows that the prey isocline is best fitted by an L-shaped function that has a vertical and a horizontal part. The predator isocline is vertical. This shape of isoclines corresponds with the Lotka-Volterra and the Rosenzweig-MacArthur predator-prey models that assume a prey refuge. These results further support the idea that a prey refuge changes the prey isocline of predator-prey models from a horizontal to an L-shaped curve. Such a shape of the prey isocline effectively bounds amplitude of predator-prey oscillations, thus promotes species coexistence.

  13. Anti hyperlipidemic activity of Tephrosia purpurea plant extracts in poloxomer 407 induced hyperlipidemic rats

    Directory of Open Access Journals (Sweden)

    Pankti P. Dalwadi

    2014-12-01

    Full Text Available Aim & Objective: Screening Of Antihyperlipidemic Activity of Tephrosia purpurea Plant Extracts.   Material & Method: Screening of antihyperlipidemic was done by using Tephrosia purpurea Leaves, Stem and Whole plant (except Leaves extracts. Part extracts used for antihyperlipidemic activity were stem (500 mg/kg, leaves (400mg/kg and whole plant extracts except leaves at the dose of (300mg/kg, 600mg/kg.Hyperlipidemia was administered in experimental animals using Poloxomer 407 by intraperitoneal administration at the dose of 1g/kg. Blood was withdrawn through retro orbital puncture at 15& 24 hrs intervals. Antihyperlipidemic activity of Tephrosia purpurea plant extracts were evaluated by estimation of lipid profiles.Results: Estimation of lipid profile shows that Tephrosia purpurea stem extract (500mg/kg, Tephrosia purpurea leaves extract (400mg/kg, Tephrosia purpurea whole plant extract (300mg/kg shows the less significant antihyperlipidemic activity. While Tephrosia purpurea whole plant extract at the dose of 600mg/kg shows potent antihyperlipidemic activity. It decreases TC, TG, LDL, VLDL and increases HDL levels. Tephrosia purpurea whole plant extract 600 mg/kg shows significant antihyperlipidemic activity as standard drug Atorvastatin.Conclusion: Hydro methanolic extracts of Tephrosia purpurea whole plant inhibits cholesterol and triglycerides synthesis. Increasing in stimulation of lipolysis by lipoprotein lipase  is responsible for plasma triglycerides hydrolysis. The elevation of serum cholesterol levels following i.p. injection of Poloxomer 407 solution to rats was due to stimulation of 3-hydroxy-3-rmethylglutaryl-Co-enzyme A (HMG-Co A reductase activity in the liver by the Poloxomer. Hydro methanolic extract of Tephrosia purpurea Showed lowering of TG levels by increasing the lipoprotein lipase activities. The cholesterol lowering effect of Tephrosia purpurea extract were observed in rats treated with the Poloxomer 407 by the

  14. Prey detection and prey capture in copepod nauplii

    DEFF Research Database (Denmark)

    Bruno, Eleonora; Borg, Marc Andersen; Kiørboe, Thomas

    2012-01-01

    current that pulls in the prey from behind towards the mouth. The feeding-current feeding nauplius detects prey arriving in the feeding current but only when the prey is intercepted by the setae on the feeding appendages. This elicits an altered motion pattern of the feeding appendages that draws...

  15. Global stability of predator-prey system with alternative prey.

    Science.gov (United States)

    Sahoo, Banshidhar

    2013-01-01

    A predator-prey model in presence of alternative prey is proposed. Existence and local stability conditions for interior equilibrium points are derived. Global stability conditions for interior equilibrium points are also found. Bifurcation analysis is done with respect to predator's searching rate and handling time. Bifurcation analysis confirms the existence of global stability in presence of alternative prey.

  16. Prey detection and prey capture in copepod nauplii.

    Directory of Open Access Journals (Sweden)

    Eleonora Bruno

    Full Text Available Copepod nauplii are either ambush feeders that feed on motile prey or they produce a feeding current that entrains prey cells. It is unclear how ambush and feeding-current feeding nauplii perceive and capture prey. Attack jumps in ambush feeding nauplii should not be feasible at low Reynolds numbers due to the thick viscous boundary layer surrounding the attacking nauplius. We use high-speed video to describe the detection and capture of phytoplankton prey by the nauplii of two ambush feeding species (Acartia tonsa and Oithona davisae and by the nauplii of one feeding-current feeding species (Temora longicornis. We demonstrate that the ambush feeders both detect motile prey remotely. Prey detection elicits an attack jump, but the jump is not directly towards the prey, such as has been described for adult copepods. Rather, the nauplius jumps past the prey and sets up an intermittent feeding current that pulls in the prey from behind towards the mouth. The feeding-current feeding nauplius detects prey arriving in the feeding current but only when the prey is intercepted by the setae on the feeding appendages. This elicits an altered motion pattern of the feeding appendages that draws in the prey.

  17. Biological effects of Echinacea purpurea on human blood cells.

    Science.gov (United States)

    Joksić, Gordana; Petrović, Sandra; Joksić, Ivana; Leskovac, Andreja

    2009-06-01

    The aim of this study was to investigate radioprotective properties of Echinacea purpurea tablets in vivo. We analysed lymphocyte chromosome aberrations (CA), micronuclei (MN), apoptosis of leukocytes and haematological parameters in a group of radiation workers who were identified as carrying dicentric chromosomes in their lymphocytes. All radiation workers were taking two 275 mg Echinacea tablets b.i.d., according to a pharmacist's recommendation. All parameters were analysed before and after the two-week treatment. At the end of the treatment lymphocyte CA frequency dropped significantly, and the number of apoptotic cells increased. The inverse lymphocyte-to-granulocyte ratio at the beginning of the study changed to normal at its end. In conclusion, biological effects observed after administration of Echinacea purpurea preparation suggest that it may be beneficial for the prevention of adverse health effects in workers exposed to ionising radiation.

  18. Antioxidant activity of fraction of Tephrosia purpurea linn.

    Directory of Open Access Journals (Sweden)

    Soni K

    2006-01-01

    Full Text Available The ethanol extract of Tephrosia purpurea Linn. (Family: Leguminosae was found to significantly inhibit the carbon tetrachloride-induced lipid peroxidation in vivo and superoxide generation in vivo . The ethyl acetate fraction of the same extract was studied for free radical scavenging and antilipid peroxidation activity. The IC50 values in both of these in vitro assays were found to be significantly reduced for ethyl acetate fraction compared with the ethanolic extract of the plant. The observation was further supported by comparing the in vivo antioxidant activity for both the ethanolic extract and its ethyl acetate fraction. The study concluded that the ethanolic extract of T. purpurea exhibits antioxidant activity in vivo and the ethyl acetate soluble fraction has improved antioxidant potential than the extract.

  19. Wound healing potential of Tephrosia purpurea (Linn.) Pers. in rats.

    Science.gov (United States)

    Lodhi, Santram; Pawar, Rajesh Singh; Jain, Alok Pal; Singhai, A K

    2006-11-24

    Tephrosia purpurea is a well-known herb for its hepatoprotective, anticancer, antiulcer, antibacterial and in healing bleeding piles, etc. The present study was aimed for wound healing potential of ethanolic extract of Tephrosia purpurea (aerial part) in the form of simple ointment using three types of wound models in rats as incision wound, excision wound and dead space wound. The results were comparable to standard drug Fluticasone propionate ointment, in terms of wound contraction, tensile strength, histopathological and biochemical parameters such as hydroxyproline content, protein level, etc. Histopathological study showed significant (P<0.05) increase in fibroblast cells, collagen fibres and blood vessels formation. All parameters were observed significant (P<0.05) in comparison to control group.

  20. [Production systems of Spondias purpurea (Anacardiaceae) in Central West Mexico].

    Science.gov (United States)

    Ramírez Hernández, Blanca C; Barrios Eulogio, Pimienta; Castellanos Ramos, Javier Z; Muñoz Urias, Alejandro; Palomino Hasbach, Guadalupe; Pimienta Barrios, Enrique

    2008-06-01

    Morphological, physical and chemical traits related with fruit quality characteristics of Spondias purpurea L. agroecosystems were studied in Central-West Mexico for wild and cultivated populations. Spondias purpurea regularly thrive in shallow, rocky infertile soils unsuitable for conventional crops. The weight, axial and radial length, pH, total soluble solids (SST), reducing sugars, proteins and mineral content in fruits were recorded. The mean fresh fruit weight was superior in the cultivated varieties (20 g) than in the wild (16 g). Similarly the highest values of pH, SST, reducing sugars and protein content (3.3, 12.15 degrees Brix, 0.38 g/100 g and 1.18 g/100 g, respectively) were observed in the cultivated plantations compared with wild populations (3.0, 8.31 degrees Brix, 0.24 g/100 g and 0.14 g/100 g, respectively). In cultivated plantations, productivity ranged from 0.15 ton ha(-1) to 5.0 ton ha(-1), and must be considered satisfactory, considering the low inputs of fertilizers and pesticides applied to orchards. The fruits of S. purpurea are similar in nutrimental content to more important commercial fruit species; it produces fresh fruits during the dry months of spring, when few fresh fruits are available in the local markets. In addition, S. purpurea is a source of water and food for domestic animals and wild fauna. These traits emphasize their agronomical and ecological importance for tropical and subtropical environments, where it can also be used in reforestation programs because it can grow in infertile rocky soils, and in agroecosystems inhabited by low income farmers that practice subsistence agriculture. In fact, the cultivation of Spondias has helped convert marginal lands into productive lands.

  1. Antihepatotoxic activity of eclipta alba, tephrosia purpurea and boerhaavia diffusa.

    Science.gov (United States)

    Murthy, V N; Reddy, B P; Venkateshwarlu, V; Kokate, C K

    1992-01-01

    Alcoholic and chloroform extracts of E. albaT. purpurea and B. diffusa were screened for antihepatotoxic activity. The extracts were given after the liver was damaged with CCl4. Liver function was assessed based on liver to boy weight ratio, pentobarbitone sleep time, serum levels of transaminase (SGPT, SGOT), alkaline phosphatase (SALP) and bilirubin. Alcoholic extract of E. alba was found to have good antihepatotoxic activity.

  2. Absolute configuration of novel bioactive flavonoids from Tephrosia purpurea.

    Science.gov (United States)

    Chang, L C; Chávez, D; Song, L L; Farnsworth, N R; Pezzuto, J M; Kinghorn, A D

    2000-02-24

    [structure: see text] Three novel flavonoids, (+)-tephrorins A (1) and B (2) and (+)-tephrosone (3), were isolated from Tephrosia purpurea. Their structures were elucidated by NMR spectral analysis, and their absolute configurations were determined by Mosher ester methodology. Compounds 1 and 2 are flavanones containing an unusual tetrahydrofuran moiety. Compounds 1-3 were evaluated for their potential cancer chemopreventive properties using a cell-based quinone reductase induction assay.

  3. Phytotherapeutic effects of Echinacea purpurea in gamma-irradiated mice

    Science.gov (United States)

    Abouelella, Amira M. K.; Tawfik, Sameh S.; Zahran, Ahmed M.

    2007-01-01

    Echinacea (E.) purpurea herb is commonly known as the purple coneflower, red sunflower and rudbeckia. In this paper, we report the curative efficacy of an Echinacea extract in γ-irradiated mice. E. purpurea was given to male mice that were divided into five groups (control, treated, irradiated, treated before irradiation & treated after irradiation) at a dose of 30 mg/kg body weight for 2 weeks before and after irradiation with 3 Gy of γ-rays. The results reflected the detrimental reduction effects of γ-rays on peripheral blood hemoglobin and the levels of red blood cells, differential white blood cells, and bone marrow cells. The thiobarbituric acid-reactive substances (TBARs) level, Superoxide dismutase (SOD) and glutathione peroxidase (GSPx) activities and DNA fragmentation were also investigated. FT-Raman spectroscopy was used to explore the structural changes in liver tissues. Significant changes were observed in the microenvironment of the major constituents, including tyrosine and protein secondary structures. E. purpurea administration significantly ameliorated all estimated parameters. The radio-protection effectiveness was similar to the radio-recovery curativeness in comparison to the control group in most of the tested parameters. The radio-protection efficiency was greater than the radio-recovery in hemoglobin level during the first two weeks, in lymphoid cell count and TBARs level at the fourth week and in SOD activity during the first two weeks, as compared to the levels of these parameters in the control group. PMID:17993747

  4. Chicoric Acid Levels in Commercial Basil (Ocimum basilicum) and Echinacea purpurea Products

    Science.gov (United States)

    Recently, we reported fresh basil (Ocimum basilicum) leaves contain chicoric acid, which is the principal phenolic compound in Echinacea purpurea and purportedly an active ingredient in dietary supplements derived from E. purpurea. Here we present the results from a study evaluating chicoric acid co...

  5. Age of planted Echinacea purpurea: The factor of seed yield and quality

    Directory of Open Access Journals (Sweden)

    Jevđović Radosav

    2007-01-01

    Full Text Available Results for yield and quality of echinacea purpurea seed obtained from age of plants one, two, three, four and five year are presented. In the laboratory experiments germination energy (GE, total germination (TG and weight seed was examined. The highest yield of seed was achieved in three-year echinacea purpurea plants, and the lowest yield was achieved in one-year plants. Age of planted established influence significant on total germination. This parametar the highest of seed in three-year plants and the lowest of seed in five-year echinacea purpurea plants. The highest of germination energy of seed established for the seed deriving from three-year echinacea purpurea planted, and the lowest in one-year plants. The absolute mass of seeds the highest in one-year plants, and the lowest for the seed deriving from five-year echinacea purpurea planted. .

  6. The allometry of prey preferences.

    Directory of Open Access Journals (Sweden)

    Gregor Kalinkat

    Full Text Available The distribution of weak and strong non-linear feeding interactions (i.e., functional responses across the links of complex food webs is critically important for their stability. While empirical advances have unravelled constraints on single-prey functional responses, their validity in the context of complex food webs where most predators have multiple prey remain uncertain. In this study, we present conceptual evidence for the invalidity of strictly density-dependent consumption as the null model in multi-prey experiments. Instead, we employ two-prey functional responses parameterised with allometric scaling relationships of the functional response parameters that were derived from a previous single-prey functional response study as novel null models. Our experiments included predators of different sizes from two taxonomical groups (wolf spiders and ground beetles simultaneously preying on one small and one large prey species. We define compliance with the null model predictions (based on two independent single-prey functional responses as passive preferences or passive switching, and deviations from the null model as active preferences or active switching. Our results indicate active and passive preferences for the larger prey by predators that are at least twice the size of the larger prey. Moreover, our approach revealed that active preferences increased significantly with the predator-prey body-mass ratio. Together with prior allometric scaling relationships of functional response parameters, this preference allometry may allow estimating the distribution of functional response parameters across the myriads of interactions in natural ecosystems.

  7. Wolf-prey relations

    Science.gov (United States)

    Mech, L. David; Peterson, Rolf O.; Mech, L. David; Boitani, Luigi

    2003-01-01

    As I (L.D. MECH) watched from a small ski plane while fifteen wolves surrounded a moose on snowy Isle Royale, I had no idea this encounter would typify observations I would make during 40 more years of studying wolf-prey relations.My usual routine while observing wolves hunting was to have my pilot keep circling broadly over the scene so I could watch the wolves’ attacks without disturbing any of the animals. Only this time there was no attack. The moose held the wolves at bay for about 5 minutes (fig. 5.1), and then the pack left.From this observation and many others of wolves hunting moose, deer, caribou, muskoxen, bison, elk, and even arctic hares, we have come to view the wolf as a highly discerning hunter, a predator that can quickly judge the cost/benefit ratio of attacking its prey. A successful attack, and the wolf can feed for days. One miscalculation, however, and the animal could be badly injured or killed. Thus wolves generally kill prey that, while not always on their last legs, tend to be less fit than the conspecifics and thus closer to death. The moose that the fifteen wolves surrounded had not been in this category, so when the wolves realized it, they gave up. This is most often the case when wolves hunt.

  8. Echinacea purpurea aerial extract alters course of influenza infection in mice.

    Science.gov (United States)

    Fusco, Dahlene; Liu, Xinyan; Savage, Caroline; Taur, Ying; Xiao, Weilie; Kennelly, Edward; Yuan, Jianda; Cassileth, Barrie; Salvatore, Mirella; Papanicolaou, Genovefa A

    2010-05-21

    Influenza infection is a major clinical problem and Echinacea purpurea, a widely consumed botanical product, is purported to alter the course of respiratory infections including influenza. Mice infected with WSN influenza A and treated with E. purpurea polysaccharide extract had less weight loss than untreated mice but similar pulmonary viral titers. Echinacea-treated mice had lower systemic and pulmonary KC and IL-10 levels and lower systemic IFN-gamma levels following influenza infection. These suggest that E. purpurea alters the clinical course of influenza infection in mice through modulation of cytokines and not direct antiviral activity. Copyright 2010. Published by Elsevier Ltd.

  9. Influence of ethanolic extract of Tephrosia purpurea Linn. on mast cells and erythrocytes membrane integrity.

    Science.gov (United States)

    Gokhale, A B; Dikshit, V J; Damre, A S; Kulkarni, K R; Saraf, M N

    2000-08-01

    The ethanolic extract of T. purpurea Linn. was studied for its in vitro effect on rat mast cell degranulation and erythrocyte membrane integrity in vitro. The extract in concentration of 25-200 microg/ml showed a dose-dependant inhibition of rat mast cell degranulation induded by compound 48/80 and egg albumin. T. purpurea extract was found to inhibit haemolysis of erythrocytes induced by hypotonic solution but accelerated haemolysis induced by heat at a concentration of 100 microg/ml. The studies reveal that the ethanolic extract of T. purpurea may inhibit degranulation of mast cells by a mechanism other than membrane stabilization.

  10. Goshawk prey have more bacteria than non-prey.

    Science.gov (United States)

    Møller, A P; Peralta-Sánchez, J M; Nielsen, J T; López-Hernández, E; Soler, J J

    2012-03-01

    1. Predators often prey on individuals that are sick or otherwise weakened. Although previous studies have shown higher abundance of parasites in prey, whether prey have elevated loads of micro-organisms remains to be determined. 2. We quantified the abundance of bacteria and fungi on feathers of woodpigeons Columba palumbus L., jays Garrulus glandarius L. and blackbirds Turdus merula L. that either fell prey to goshawks Accipiter gentilis L. or were not depredated. 3. We found an almost three-fold increase in bacterial load of prey compared with non-prey, while there was no significant difference between prey and non-prey in level of fungal infection of the plumage. 4. The results were not confounded by differences in size or mass of feathers, date of collection of feathers, or date of analysis of feathers for micro-organisms. 5. These findings suggest a previously unknown contribution of bacteria to risk of predation, with important implications for behaviour, population ecology and community ecology. © 2011 The Authors. Journal of Animal Ecology © 2011 British Ecological Society.

  11. Predator-prey systems depend on a prey refuge.

    Science.gov (United States)

    Chivers, W J; Gladstone, W; Herbert, R D; Fuller, M M

    2014-11-07

    Models of near-exclusive predator-prey systems such as that of the Canadian lynx and snowshoe hare have included factors such as a second prey species, a Holling Type II predator response and climatic or seasonal effects to reproduce sub-sets of six signature patterns in the empirical data. We present an agent-based model which does not require the factors or constraints of previous models to reproduce all six patterns in persistent populations. Our parsimonious model represents a generalised predator and prey species with a small prey refuge. The lack of the constraints of previous models, considered to be important for those models, casts doubt on the current hypothesised mechanisms of exclusive predator-prey systems. The implication for management of the lynx, a protected species, is that maintenance of an heterogeneous environment offering natural refuge areas for the hare is the most important factor for the conservation of this species.

  12. Ecoepidemic predator-prey model with feeding satiation, prey herd behavior and abandoned infected prey.

    Science.gov (United States)

    Kooi, Bob W; Venturino, Ezio

    2016-04-01

    In this paper we analyse a predator-prey model where the prey population shows group defense and the prey individuals are affected by a transmissible disease. The resulting model is of the Rosenzweig-MacArthur predator-prey type with an SI (susceptible-infected) disease in the prey. Modeling prey group defense leads to a square root dependence in the Holling type II functional for the predator-prey interaction term. The system dynamics is investigated using simulations, classical existence and asymptotic stability analysis and numerical bifurcation analysis. A number of bifurcations, such as transcritical and Hopf bifurcations which occur commonly in predator-prey systems will be found. Because of the square root interaction term there is non-uniqueness of the solution and a singularity where the prey population goes extinct in a finite time. This results in a collapse initiated by extinction of the healthy or susceptible prey and thereafter the other population(s). When also a positive attractor exists this leads to bistability similar to what is found in predator-prey models with a strong Allee effect. For the two-dimensional disease-free (i.e. the purely demographic) system the region in the parameter space where bistability occurs is marked by a global bifurcation. At this bifurcation a heteroclinic connection exists between saddle prey-only equilibrium points where a stable limit cycle together with its basin of attraction, are destructed. In a companion paper (Gimmelli et al., 2015) the same model was formulated and analysed in which the disease was not in the prey but in the predator. There we also observed this phenomenon. Here we extend its analysis using a phase portrait analysis. For the three-dimensional ecoepidemic predator-prey system where the prey is affected by the disease, also tangent bifurcations including a cusp bifurcation and a torus bifurcation of limit cycles occur. This leads to new complex dynamics. Continuation by varying one parameter

  13. In vitro and in vivo studies of the immunomodulatory effect of Echinacea purpurea on dendritic cells

    Directory of Open Access Journals (Sweden)

    N.E. El-Ashmawy

    2015-12-01

    Conclusion: Our findings suggest that the immunomodulatory mechanisms of E. purpurea impact generation fate of DCs rather than differentiation stages. The results obtained in the in vivo study utilizing murine splenic DCs supported those observed in vitro.

  14. Observations on tephrosia purpurea (L.) pers. Growing in and around gauhat (assam).

    Science.gov (United States)

    Karnick, C R; Majumdar, R

    1982-07-01

    Observations on Tephrosia purpurea (L.) pers. Which is known as Sarapunkha in Ayurveda, growing in and around Gauhati (Assam) has been systematically discussed in this paper. The Ethno-botanical records of the plant are also described here.

  15. OBSERVATIONS ON TEPHROSIA PURPUREA (L.) PERS. GROWING IN AND AROUND GAUHAT (ASSAM)

    OpenAIRE

    Karnick, C.R.; Majumdar, R

    1982-01-01

    Observations on Tephrosia purpurea (L.) pers. Which is known as Sarapunkha in Ayurveda, growing in and around Gauhati (Assam) has been systematically discussed in this paper. The Ethno-botanical records of the plant are also described here.

  16. Birds of Prey of Wisconsin.

    Science.gov (United States)

    Hamerstrom, Frances

    This copiously illustrated document is designed to be a field quide to birds of prey that are common to Wisconsin, as well as to some that enter the state occasionally. An introduction discusses birds of prey with regard to migration patterns, the relationship between common names and the attitudes of people toward certain birds, and natural signs…

  17. Prey capture by harbor porpoises

    DEFF Research Database (Denmark)

    Miller, Lee

    2008-01-01

    their ultrasonic clicks as biosonar for orientation and detection of prey (mostly smaller pelagic and bottom dwelling fish), and for communication.  For studying wild animals, hydrophone arrays [Villadsgaard et al. J.Exp.Biol. 210 (2007)] and acoustic (time/depth) tags [Akamatsu et al. Deep Sea Research II 54...... (2007)] have been used.  For studying captive animals, arrays and video techniques [Verfuss et al. J.Exp.Biol. 208 (2005)] as well as miniature acoustic-behavioral tags [Deruiter et al. JASA 123 (2008)] have been used.  While searching for prey, harbor porpoises use clicks at long intervals (~50 ms......) that progressively decrease when closing on an object.  After detecting the prey, the click interval stabilizes and then becomes progressively shorter while approaching the prey.  The sequence ends in a terminal, high repetition rate buzz (~500 clicks/s) just before capturing the prey (a video will be shown...

  18. Research on the biology of Echinacea pallida Nutt. and Echinacea purpurea (L. Moench (II

    Directory of Open Access Journals (Sweden)

    Leon Sorin MUNTEAN

    1991-08-01

    Full Text Available In the second year of vegetation, after emergence, Echinacea pallida Nutt. and Echinacea purpurea (L. Moench, form a leaf rosette and the first floral shoots appear in June. Plant vigour is significantly higher in Echinacea purpurea than in E. pallida, saved for roots. E. pallida is tetraploid, 2n=4x=44 chromosomes, of small size, between 5,87 and 3,04 microns, relatively easy to individualize by their shape and size.

  19. Activation of PPARgamma by Metabolites from the Flowers of Purple Coneflower (Echinacea purpurea)

    DEFF Research Database (Denmark)

    Christensen, Kathrine B; Petersen, Rasmus K; Petersen, Sidsel;

    2009-01-01

    Thiazolidinediones are insulin sensitizing drugs that target the peroxisome proliferator-activated receptor (PPAR) gamma. An n-hexane extract of the flowers of Echinacea purpurea was found to activate PPARgamma without stimulating adipocyte differentiation. Bioassay-guided fractionations yielded...... differentiation. Compound 5 was further shown to increase insulin-stimulated glucose uptake. The data suggest that flowers of E. purpurea contain compounds with potential to manage insulin resistance and type 2 diabetes....

  20. ANTIHYPERLIPIDEMIC EFFECT OF ETHANOLIC EXTRACT OF LEAVES OF TEPHROSIA PURPUREA LINN IN DEXAMETHASONE INDUCED RATS

    OpenAIRE

    Tanvir Shaikh; Tabrej Mujawar; Rashid Akthar; Sufiyan Ahmad; Mohib Khan

    2011-01-01

    Tephrosia purpurea Linn. (family Fabaceae) is considered in system of folklore medicine in the treatment of diabetes. The present experimental investigation established the lipid lowering properties of ethanolic extract of leaves of Tephrosia purpurea Linn. on experimentally Dexamethasone induced rats. The lipid parameters studied are Total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), High density lipoprotein cholesterol (HDL-C), very low density lipoprotein cholesterol (VLD...

  1. Anti hyperlipidemic activity of Tephrosia purpurea plant extracts in poloxomer 407 induced hyperlipidemic rats

    OpenAIRE

    Pankti P. Dalwadi; Pragnesh Patani

    2014-01-01

    Aim & Objective: Screening Of Antihyperlipidemic Activity of Tephrosia purpurea Plant Extracts.   Material & Method: Screening of antihyperlipidemic was done by using Tephrosia purpurea Leaves, Stem and Whole plant (except Leaves) extracts. Part extracts used for antihyperlipidemic activity were stem (500 mg/kg), leaves (400mg/kg) and whole plant extracts except leaves at the dose of (300mg/kg, 600mg/kg).Hyperlipidemia was administered in experimental animals using Poloxomer 407 by in...

  2. Hepatoprotective activity of Tephrosia purpurea against arsenic induced toxicity in rats

    OpenAIRE

    Ravuri Halley Gora; Sushma Lalita Baxla; Priscilla Kerketta; Subhasree Patnaik; Birendra Kumar Roy

    2014-01-01

    Aim: The present study was conducted to evaluate the hepatoprotective activity of Tephrosia purpurea (TP) against sodium arsenite (NaAsO2) induced sub-acute toxicity in rats. Materials and Methods: Twenty four wistar albino rats of either sex were randomly divided into three groups. Group II and III were orally administered with sodium arsenite (10 mg/kg) daily in drinking water for 28 days. Additionally Group III was orally treated with hydro-alcoholic extract of Tephrosia purpurea (TP) ...

  3. Acute and subacute oral toxicity evaluation of Tephrosia purpurea extract in rodents

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    Talib Hussain

    2012-04-01

    Full Text Available Objective: To evaluate the acute and subacute toxicity of 50% ethanolic extract of Tephrosia purpurea (T. purpurea in rodents. Methods: The acute toxicity test was conducted in Swiss albino mice. The extract of T. purpurea was administrated in single doses of 50, 300 and 2000 mg/ kg and observed for behavioral changes and mortality, if any. In subacute toxicity study, Wistar rats of either sex were administered two doses of T. purpurea i.e., 200 and 400 mg/kg (One-tenth and one-fifth of the maximum tolerated dose, p.o. for 4 weeks. During 28 days of treatment, rats were observed weekly for any change in their body weight, food and water intake. At the end of 28 days, rats were sacrificed for hematological, biochemical and histopathology study. Results: In the acute toxicity study, T. purpurea was found to be well tolerated upto 2 000 mg/kg, produced neither mortality nor changes in behavior in mice. In subacute toxicity study, T. purpurea at dose level of 200 and 400 mg/kg did not produce any significant difference in their body weight, food and water intake when compared to vehicle treated rats. It also showed no significant alteration in hematological and biochemical parameters in experimental groups of rats apart from a decrease in aspartate transaminase, alanine transaminase and alkaline phosphate content at the dose of 400 mg/kg. Histopathological study revealed normal architecture of kidney and liver of T. purpurea treated rats. Conclusions: These results demonstrated that there is a wide margin of safety for the therapeutic use of T. purpurea and further corroborated the traditional use of this extract as an anti hepatocarcinogenic agent

  4. Chemical constituents of essential oils of Tephrosia purpurea and Ipomoea carnea and their repellent activity against Odoiporus longicollis

    OpenAIRE

    Sahayaraj Kitherian; Kombiah Poolpandi; Dikshit Anand K.; Rathi Martin J.

    2015-01-01

    Chemical constituents of essential oils (EOs) obtained from stem and root of Tephrosia purpurea (Linn.) Pers. and Ipomoea carnea Jacq. were investigated by Gas Chromatography-Mass Spectrometry (GC-MS). Total lipid and oil content was high in the stem than the root of T. purpurea and I. carnea. Essential oils extracted from the stem and root of T. purpurea and I. carnea showed 9 and 8 compounds respectively. Hexadecanoic acid was found to be the principal co...

  5. Effect of high pressure pasteurization on bacterial load and bioactivity of Echinacea purpurea.

    Science.gov (United States)

    Chen, Xiu-Min; Hu, Chun; Raghubeer, Errol; Kitts, David D

    2010-09-01

    High hydrostatic pressure (HHP) technology was applied to organic Echinacea purpurea (E. purpurea) roots and flowers to determine the feasibility of using this technology for cold herb pasteurization, to produce microbiologically safe and shelf-stable products for the natural health products (NHPs) industry. HHP significantly (P purpurea methanol-derived extracts, evaluated in both chemical (2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) [ABTS] and oxygen radical absorption capacity [ORAC] assay) and in cell culture models (RAW264, 7 macrophage, H(2)O(2)-induced intracellular oxidation, and lipopolysaccharide [LPS]-induced nitric oxide production), was not adversely affected by the application of HHP at both 2 and 5 min at 600 mPa. Furthermore, HHP did not affect the capacity of E. purpurea extracts to suppress nitric oxide production in LPS-activated macrophage cells. Therefore, our results show that HHP is an effective pasteurization process treatment to reduce microbial-contamination load while not adversely altering chemical and bioactive function of active constituents present in organic E. purpurea. Our study reports for the first time, the effectiveness of using high hydrostatic pressure (HHP) technology pressure to pasteurize E. purpurea root and flower, and the comparative retention of bioactive phytochemicals. Therefore, this technique can be used in food and natural health product industries to produce high-quality, microbiologically safe, and shelf-stable products.

  6. Echinacea purpurea and P-glycoprotein drug transport in Caco-2 cells.

    Science.gov (United States)

    Hansen, Torstein Schrøder; Nilsen, Odd Georg

    2009-01-01

    Echinacea is widely used as a medical herbal product, but its interaction potential with the drug efflux transporter P-glycoprotein (P-gp) has not yet been evaluated. The interaction potential of Echinacea purpurea towards P-gp mediated drug transport was studied in human intestinal Caco-2 cells. Digoxin (30 nm) was used as a substrate and verapamil as a control inhibitor. Ethanol, 0.8%, needed for herbal extraction and compatibility with the commercial products, inhibited the net digoxin flux by 18%. E. purpurea influenced to a higher degree the B-A transport of digoxin than the A-B transport. A minor increase in net digoxin flux was observed at low concentrations of E. purpurea, an effect anticipated to be allosteric in nature. At higher concentrations, from 0.4 to 6.36 mg dry weight/mL, a statistically significant linear dose-related decrease was observed in the net digoxin flux, indicating a dose dependent E. purpurea inhibition of P-gp. Both Vmax and Km of the net digoxin flux, calculated to 23.7 nmol/cm2/h and 385 microm, respectively, decreased in the presence of E. purpurea in an uncompetitive fashion. Although the effects of Echinacea purpurea on systemic P-gp mediated drug transport are probably limited, an influence on drug bioavailability can not be excluded. Copyright 2008 John Wiley & Sons, Ltd.

  7. Chemical constituents of essential oils of Tephrosia purpurea and Ipomoea carnea and their repellent activity against Odoiporus longicollis

    Directory of Open Access Journals (Sweden)

    Sahayaraj Kitherian

    2015-01-01

    Full Text Available Chemical constituents of essential oils (EOs obtained from stem and root of Tephrosia purpurea (Linn. Pers. and Ipomoea carnea Jacq. were investigated by Gas Chromatography-Mass Spectrometry (GC-MS. Total lipid and oil content was high in the stem than the root of T. purpurea and I. carnea. Essential oils extracted from the stem and root of T. purpurea and I. carnea showed 9 and 8 compounds respectively. Hexadecanoic acid was found to be the principal constituent of stem (69.61% and root (46.97% of T. purpurea while 70.61and 88.89% for stem and root, respectively in the case of I. carnea. The findings of the present study suggest that T. purpurea and I. carnea EOs can be used as a source of hexadecanoic acid which could be used for industrial purposes. The essential oils of T. purpurea and I. carnea showed strong repellent activity for males (-0.73 and -0.70 for T. purpurea and I. carnea stem EO respectively than females (-0.63 and -0.59 for T. purpurea and I. carnea stem EO respectively against banana pseudostem weevil Odoiporus longicollis. The results indicated that the active compounds of essential oils from stems of T. purpurea and I. carnea can be explored as natural repellents for control of Odoiporus longicollis.

  8. The effect of coloured light on Ipomoea purpurea growth

    Science.gov (United States)

    Surducan, Vasile; Lung, Ildiko; Surducan, Emanoil

    2009-08-01

    Ipomoea purpurea is a climbing ornamental plant native to Mexico. The paper is describing the experimental setup and results for indoor growing plants exposed to white LED light (inside a reference chamber) and four different wavelength LED lights (inside a measure chamber). Four growing experiments of 12-15 days, took place in identical environmental conditions (identical temperature and relative humidity inside the reference and measure chambers, similar lighting conditions and soil moisture). At the end of the experiments, the plant chlorophyll and xanthophylls content have been measured and the plant aspect (vegetal mass, leaves colour and robustness) has been observed. The smallest content in chlorophyll (a and b) was developed by the plants growth in blue light (480 nm), however those plants where 10% taller than plants growth in white light, but less robust. The higher content in carotenoids and xanthophylls was observed in plants which growth in white and red light.

  9. Tephrosia purpurea alleviates phorbol ester-induced tumor promotion response in murine skin.

    Science.gov (United States)

    Saleem, M; Ahmed Su; Alam, A; Sultana, S

    2001-02-01

    In recent years, considerable emphasis has been placed on identifying new cancer chemopreventive agents, which could be useful for the human population. Tephrosia purpurea has been shown to possess significant activity against hepatotoxicity, pharmacological and physiological disorders. Earlier we showed that Tephrosia purpurea inhibits benzoyl peroxide-mediated cutaneous oxidative stress and toxicity. In the present study, we therefore assessed the effect of Tephrosia purpurea on 12-O-tetradecanoyl phorbal-13-acetate (TPA; a well-known phorbol ester) induced cutaneous oxidative stress and toxicity in murine skin. The pre-treatment of Swiss albino mice with Tephrosia purpurea prior to application of croton oil (phorbol ester) resulted in a dose-dependent inhibition of cutaneous carcinogenesis. Skin tumor initiation was achieved by a single topical application of 7,12-dimethyl benz(a)anthracene (DMBA) (25 microg per animal per 0.2 ml acetone) to mice. Ten days later tumor promotion was started by twice weekly topical application of croton oil (0.5% per animal per 0.2 ml acetone, v /v). Topical application of Tephrosia purpurea 1 h prior to each application of croton oil (phorbol ester) resulted in a significant protection against cutaneous carcinogenesis in a dose-dependent manner. The animals pre-treated with Tephrosia purpurea showed a decrease in both tumor incidence and tumor yield as compared to the croton oil (phorbol ester)-treated control group. In addition, a significant reduction in TPA-mediated induction in cutaneous ornithine decarboxylase (ODC) activity and [3H]thymidine incorporation was also observed in animals pre-treated with a topical application of Tephrosia purpurea. The effect of topical application of Tephrosia purpurea on TPA-mediated depletion in the level of enzymatic and non-enzymatic molecules in skin was also evaluated and it was observed that topical application of Tephrosia purpurea prior to TPA resulted in the significant recovery of

  10. Prey-predator model with a nonlocal consumption of prey.

    Science.gov (United States)

    Banerjee, M; Volpert, V

    2016-08-01

    The prey-predator model with nonlocal consumption of prey introduced in this work extends previous studies of local reaction-diffusion models. Linear stability analysis of the homogeneous in space stationary solution and numerical simulations of nonhomogeneous solutions allow us to analyze bifurcations and dynamics of stationary solutions and of travelling waves. These solutions present some new properties in comparison with the local models. They correspond to different feeding strategies of predators observed in ecology.

  11. Prey-predator model with a nonlocal consumption of prey

    Science.gov (United States)

    Banerjee, M.; Volpert, V.

    2016-08-01

    The prey-predator model with nonlocal consumption of prey introduced in this work extends previous studies of local reaction-diffusion models. Linear stability analysis of the homogeneous in space stationary solution and numerical simulations of nonhomogeneous solutions allow us to analyze bifurcations and dynamics of stationary solutions and of travelling waves. These solutions present some new properties in comparison with the local models. They correspond to different feeding strategies of predators observed in ecology.

  12. Prey capture by harbour porpoises

    DEFF Research Database (Denmark)

    Verfuss, Ursula; Miller, Lee; Pilz, Peter

    their ultrasonic clicks as biosonar for orientation and detection of prey (mostly smaller pelagic and bottom dwelling fish), and for communication.  For studying wild animals, hydrophone arrays [Villadsgaard et al. J.Exp.Biol. 210 (2007)] and acoustic (time/depth) tags [Akamatsu et al. Deep Sea Research II 54...... (2007)] have been used.  For studying captive animals, arrays and video techniques [Verfuß et al. J.Exp.Biol. 208 (2005)] as well as miniature acoustic-behavioral tags [Deruiter et al. JASA 123 (2008)] have been used.  While searching for prey, harbor porpoises use clicks at long intervals (>50 ms......) that progressively decrease when closing on a landmark.  The source levels of captive animals reduce by about half for each halving of the distance to the target.  After detecting the prey, the click interval first stabilizes at about 50 ms and then becomes progressively shorter while approaching the prey...

  13. Prey detection in a cruising copepod

    DEFF Research Database (Denmark)

    Kjellerup, Sanne; Kiørboe, Thomas

    2012-01-01

    Small cruising zooplankton depend on remote prey detection and active prey capture for efficient feeding. Direct, passive interception of prey is inherently very inefficient at low Reynolds numbers because the viscous boundary layer surrounding the approaching predator will push away potential prey....... Yet, direct interception has been proposed to explain how rapidly cruising, blind copepods feed on non-motile phytoplankton prey. Here, we demonstrate a novel mechanism for prey detection in a cruising copepod, and describe how motile and non-motile prey are discovered by hydromechanical and tactile...

  14. Prey detection in a cruising copepod

    DEFF Research Database (Denmark)

    Kjellerup, Sanne; Kiørboe, Thomas

    2012-01-01

    Small cruising zooplankton depend on remote prey detection and active prey capture for efficient feeding. Direct, passive interception of prey is inherently very inefficient at low Reynolds numbers because the viscous boundary layer surrounding the approaching predator will push away potential prey....... Yet, direct interception has been proposed to explain how rapidly cruising, blind copepods feed on non-motile phytoplankton prey. Here, we demonstrate a novel mechanism for prey detection in a cruising copepod, and describe how motile and non-motile prey are discovered by hydromechanical and tactile...

  15. The bumblebee Bombus hortorum is the main pollinating visitor to Digitalis purpurea (Common Foxglove in a U.K. population

    Directory of Open Access Journals (Sweden)

    Arthur Broadbent

    2012-06-01

    Full Text Available Specialization in plant-pollinator systems represents an important issue for both the ecological understanding and conservation of these systems. We investigated the extent to which the bumblebee Bombus hortorum (Linnaeus is the main potential pollinator of Common Foxglove, Digitalis purpurea L. Twenty D. purpurea patches were selected in North Yorkshire, U.K., ten each in woodland and garden or park habitat. All insects visiting D. purpurea within the patches were recorded over seventy 30-min bouts. The relative frequency of insect visitors to other flowering plant species within 15 m of each patch was also determined. B. hortorum and B. pascuorum were the two most frequent visitors to D. purpurea, accounting for 82 - 92% and 3 -17%, respectively, of all insect visits (n = 1682, depending on habitat. B. hortorum showed a significant preference for visiting D. purpurea relative to its frequency of visits to other available plant species. The relationship of D. purpurea with B. hortorum, which pollinates several plant species with long corollas, therefore represents a potential case of asymmetric specialization, albeit one that may vary spatially. Because D. purpurea reproduction appears dependent on insect pollination, B. hortorum and B. pascuorum may help underpin the viability of D. purpurea populations.

  16. In vitro characterization of a nineteenth-century therapy for smallpox.

    Science.gov (United States)

    Arndt, William; Mitnik, Chandra; Denzler, Karen L; White, Stacy; Waters, Robert; Jacobs, Bertram L; Rochon, Yvan; Olson, Victoria A; Damon, Inger K; Langland, Jeffrey O

    2012-01-01

    In the nineteenth century, smallpox ravaged through the United States and Canada. At this time, a botanical preparation, derived from the carnivorous plant Sarracenia purpurea, was proclaimed as being a successful therapy for smallpox infections. The work described characterizes the antipoxvirus activity associated with this botanical extract against vaccinia virus, monkeypox virus and variola virus, the causative agent of smallpox. Our work demonstrates the in vitro characterization of Sarracenia purpurea as the first effective inhibitor of poxvirus replication at the level of early viral transcription. With the renewed threat of poxvirus-related infections, our results indicate Sarracenia purpurea may act as another defensive measure against Orthopoxvirus infections.

  17. In vitro characterization of a nineteenth-century therapy for smallpox.

    Directory of Open Access Journals (Sweden)

    William Arndt

    Full Text Available In the nineteenth century, smallpox ravaged through the United States and Canada. At this time, a botanical preparation, derived from the carnivorous plant Sarracenia purpurea, was proclaimed as being a successful therapy for smallpox infections. The work described characterizes the antipoxvirus activity associated with this botanical extract against vaccinia virus, monkeypox virus and variola virus, the causative agent of smallpox. Our work demonstrates the in vitro characterization of Sarracenia purpurea as the first effective inhibitor of poxvirus replication at the level of early viral transcription. With the renewed threat of poxvirus-related infections, our results indicate Sarracenia purpurea may act as another defensive measure against Orthopoxvirus infections.

  18. Root colonization by an arbuscular mycorrhizal (AM) fungus increases growth and secondary metabolism of purple coneflower, Echinacea purpurea (L.) Moench.

    Science.gov (United States)

    Araim, Ghada; Saleem, Ammar; Arnason, John T; Charest, Christiane

    2009-03-25

    Purple coneflower, Echinacea purpurea (L.) Moench, is an important phytomedicinal species that contains phenolics and alkamides with antipathogenic properties. This study aimed to examine the effect of arbuscular mycorrhizal (AM) colonization on the physiology and biochemistry of E. purpurea. It was hypothesized that AM colonization enhances the growth and secondary metabolism in E. purpurea. In this regard, a 13-week factorial greenhouse experiment was performed with E. purpurea, inoculated (or not) with the AM fungus Glomus intraradices Schenck & Smith. Overall, the results indicated that AM colonization significantly increased the mass of shoots and roots and the concentrations of proteins and most of the phenolics in the roots. Hence, the selected trait of mycorrhiza could play an important role in optimizing the growth of E. purpurea by inducing the production of secondary phytomedicinal metabolites.

  19. Predator-prey system with strong Allee effect in prey.

    Science.gov (United States)

    Wang, Jinfeng; Shi, Junping; Wei, Junjie

    2011-03-01

    Global bifurcation analysis of a class of general predator-prey models with a strong Allee effect in prey population is given in details. We show the existence of a point-to-point heteroclinic orbit loop, consider the Hopf bifurcation, and prove the existence/uniqueness and the nonexistence of limit cycle for appropriate range of parameters. For a unique parameter value, a threshold curve separates the overexploitation and coexistence (successful invasion of predator) regions of initial conditions. Our rigorous results justify some recent ecological observations, and practical ecological examples are used to demonstrate our theoretical work.

  20. Research on the biology of Echinacea angustifolia (Dc. Moench and Echinacea purpurea (L. Moench

    Directory of Open Access Journals (Sweden)

    Leon Sorin MUNTEAN

    1989-08-01

    Full Text Available Echinacea angustifolia (Dc. Moench and Echinacea purpurea (L. Moench species have been highly appreciated for their therapeutic qualities, both of them belong to the few plants of immunostimulative and antiviral properties. The adaptation and cultivation process of these plants has been initiated for medical purposes at the Cluj-Napoca Agronomy Institute. The biological researches evidenced the two species, multiplied by nursery transplant, formed a rosette of leaves during their first year of plantation. The first floral offshoots in Echinacea purpurea were seen during the months September and October (in approximately 40 percent of plants. Flowering Echinacea angustifolia appeared only sporadically the first year of cultivation. Leaves number and plant mass in both species increased markedly the first year of vegetation starting from August. Herba and radix ratio represented 74 percent and 26 percent respectively of the whole plant mass in Echinacea angustifolia and 87 percent and 13 percent respectively in Echinacea purpurea.

  1. Chromatographic methods for metabolite profiling of virus- and phytoplasma-infected plants of Echinacea purpurea.

    Science.gov (United States)

    Pellati, Federica; Epifano, Francesco; Contaldo, Nicoletta; Orlandini, Giulia; Cavicchi, Lisa; Genovese, Salvatore; Bertelli, Davide; Benvenuti, Stefania; Curini, Massimo; Bertaccini, Assunta; Bellardi, Maria Grazia

    2011-10-12

    This study was focused on the effects of virus and phytoplasma infections on the production of Echinacea purpurea (L.) Moench secondary metabolites, such as caffeic acid derivatives, alkamides, and essential oil. The identification of caffeic acid derivatives and alkamides was carried out by means of high-performance liquid chromatography-diode array detection (HPLC-DAD), HPLC-electrospray ionization-mass spectrometry (ESI-MS), and MS(2). Quantitative analysis of these compounds was carried out using HPLC-DAD. The results indicated that the presence of the two pathogens significantly decreases (P purpurea essential oil enabled the identification of 30 compounds. The main significant differences (P purpurea secondary metabolites, which is an important issue in defining the commercial quality, market value, and therapeutic efficacy of this herbal drug.

  2. Establishment of adventitious root cultures of Echinacea purpurea for the production of caffeic acid derivatives.

    Science.gov (United States)

    Paek, Kee-Yoeup; Murthy, Hosakatte Niranjana; Hahn, Eun-Joo

    2009-01-01

    Echinacace purpurea (purple cone flower) is an important medicinal plant, and widely used for phytochemical purposes. The roots are traditionally used in herbal medicines and dietary supplements as an immunostimulant in treating inflammatory and viral diseases. Extensive research work has been carried out on both the induction of adventitious roots from E. purpurea as well as established small-scale (shake flask) to large-scale (bioreactor) cultures for the production of adventitious root biomass and caffeic acid derivatives. This chapter describes the methodologies of induction of adventitious roots from explants of E. purpurea, propagation of adventitious roots in suspension cultures, estimation of total phenolics, flavonoids, and antioxidant activities. The detailed methodology for high-performance liquid chromatographic analysis of caffeic acid derivatives present in the adventitious roots is also discussed.

  3. Isolation, culture, and plant regeneration from Echinacea purpurea protoplasts.

    Science.gov (United States)

    Pan, Zeng-guang; Liu, Chun-zhao; Murch, Susan I; Saxena, Praveen K

    2006-01-01

    A plant regeneration system from the isolated protoplasts of Echinacea purpurea L. using an alginate solid/liquid culture is described in the chapter. Viable protoplasts were isolated rom 100 mg of young leaves of 4-wk-old seedlings in an isolation mixture containing 1.0% cellulase Onozuka R-10, 0.5% pectinase, and 0.3 mol/L mannitol. After isolation and purification, the mesophyll protoplasts were embedded into 0.6% Na-alginate at the density 1 x 10(-5) mL and cultured in modified Murashige and Skoog (MS) culture medium supplemented with 0.3 mol/L sucrose, 2.5 micromol/L benzylaminopurine (BA), and 5.0 micromol/L 2,4-dichlorophenoxyacetic acid (2,4-D). The visible colonies were present after 4 wk of culture. The protoplast-derived clones were transferred onto gellan gum-solidified basal medium supplemented with 1.0 micromol/L BA and 2.0 micromol/L indole-3-butyric acid (IBA) and formed compact and green calli. Shoot development was achieved by subculturing the calli onto the same basal medium supplemented with 5.0 micromol/L BA and 2.0 micromol/L IBA. Further subculture onto basal medium resulted in the regeneration of complete plantlets.

  4. [Chemical constituents from the aerial part of Echinacea purpurea].

    Science.gov (United States)

    Chen, Qiu-Ling; Wang, Lei; Feng, Feng

    2013-05-01

    To study the chemical constituents of the aerial part of Echinacea purpurea. The compounds were separated and purified by repeatedly silica gel, ODS, D101 macroporous resin, MCI, Sephadex LH-20 column chromatography and recrystallization. Their structures were elucidated on the basis of physiochemical properties and spectral analysis. Sixteen compounds were isolated and identified as (2S)-1-O-octacosanoyl glycerol (1), (5R,6S)-6-hydroxy-6-((E)-3-hydroxybut-1-enyl)-1,1, 5-trimethylcyclohexanone (2), (3S, 6E, 10R)-3, 10, 11-trihydroxy-3, 7, 11-trimethyl-dodeca-1, 6-diene (3), negunfurol (4), schensianol A (5), ent-4 (15) -eudesmene-1beta, 6alpha-diol (6), (E) -5-hydroxy-N-isobutylpentadec-2-enamide (7), syringaresinol (8), quercetin (9), ethyl laurate (10), ethyl caffeate (11), ferulic acid (12), alpha-spinasterol (13), stigmasterol (14), beta-daucosterol (15), octacosanoic acid (16). Compound 1 - 5 are isolated from the Asteraceae for the first time, compound 6 ,7, 9, 10, 12 are isolated from genus of Echinacea for the first time, compound 15, 16 are isolated from this plant for the first time.

  5. GAMMA RADIATION EFFECT ON SUPEROXIDE DISMUTASE ACTIVITY IN HYPERICUM PERFORATUM L. AND ECHINACEA PURPUREA L., MOENCH

    Directory of Open Access Journals (Sweden)

    Vlad Artenie

    2006-08-01

    Full Text Available In this paper we were focused on the activity of superoxide dismutase (SOD in Hypericum perforatum L and Echinacea purpurea L., Moench plantlets, obtained from seeds irradiated with gamma rays before germination.Total activity as well as specific activity of SOD in Hypericum perforatum L. plantlets shows an inhibition, which becames higher at higher irradiation doses. For Echinacea purpurea L. species, gamma radiation shows a slowly stimulative effect of total activity of SOD for some of the higher doses, but the specific enzyme activity is inhibated for all irradiation doses applyed on non-germinated irradiated seeds.

  6. Studies on the immunomodulatory activity of flavonoidal fraction of Tephrosia purpurea.

    Science.gov (United States)

    Damre, A S; Gokhale, A B; Phadke, A S; Kulkarni, K R; Saraf, M N

    2003-04-01

    The flavonoid fraction of Tephrosia purpurea (FFTP) was studied for its effect on cellular and humoral functions and on macrophage phagocytosis in mice. Oral administration of FFTP (10-40 mg/kg) significantly inhibited sheep red blood cells (SRBC)-induced delayed-type hypersensitivity reactions. It also produced a significant, dose-related decrease in sheep erythrocyte-specific haemagglutination antibody titre. However, the fraction failed to show a significant change in the macrophage phagocytic activity. The results obtained indicate the ability of the flavonoidal fraction of T. purpurea to modulate both the cell-mediated and the humoral components of the immune system.

  7. Echinacea purpurea: A Proprietary Extract of Echinacea purpurea Is Shown to be Safe and Effective in the Prevention of the Common Cold.

    Science.gov (United States)

    Ross, Stephanie Maxine

    2016-01-01

    The research study in this review represents the largest clinical trial to date that evaluated the safety and efficacy of Echinacea purpurea for prophylactic treatment of the common cold, in addition to investigating its risk-benefit in a long-term treatment period. The clinical application of the proprietary standardized Echinacea purpurea extract(Echinaforce) demonstrated efficacy as a preventive cold treatment option over a 4-month duration. This study showed that Echinacea’s long-term prevention was associated with a reduction in the total number of cold episodes, a reduction in the number of days with colds, and a reduction in cold episodes requiring additional medication. Furthermore, the Echinacea test agent inhibited virally confirmed colds, exhibited maximal effects on recurrent infections, and demonstrated that its preventive effects increased relative to therapy compliance and adherence to the protocol. In summary, Echinacea purpurea when taken as recommended for the prevention of the common cold appears to provide a positive risk to benefit ratio.

  8. Transcriptomic Response of Purple Willow (Salix purpurea to Arsenic Stress

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    Aymeric Yanitch

    2017-06-01

    Full Text Available Arsenic (As is a toxic element for plants and one of the most common anthropogenic pollutants found at contaminated sites. Despite its severe effects on plant metabolism, several species can accumulate substantial amounts of arsenic and endure the associated stress. However, the genetic mechanisms involved in arsenic tolerance remains obscure in many model plant species used for land decontamination (phytoremediation, including willows. The present study assesses the potential of Salix purpurea cv. ‘Fish Creek’ for arsenic phytoextraction and reveals the genetic responses behind arsenic tolerance, phytoextraction and metabolism. Four weeks of hydroponic exposure to 0, 5, 30 and 100 mg/L revealed that plants were able to tolerate up to 5 mg/L arsenic. Concentrations of 0 and 5 mg/L of arsenic treatment were then used to compare alterations in gene expression of roots, stems and leaves using RNA sequencing. Differential gene expression revealed transcripts encoding proteins putatively involved in entry of arsenic into the roots, storage in vacuoles and potential transport through the plant as well as primary and secondary (indirect toxicity tolerance mechanisms. A major role for tannin as a compound used to relieve cellular toxicity is implicated as well as unexpected expression of the cadmium transporter CAX2, providing a potential means for internal arsenic mobility. These insights into the underpinning genetics of a successful phytoremediating species present novel opportunities for selection of dedicated arsenic tolerant crops as well as the potential to integrate such tolerances into a wider Salix ideotype alongside traits including biomass yield, biomass quality, low agricultural inputs and phytochemical production.

  9. EVALUATION OF ANTIMICROBIAL AND ANTI-HISTAMINE ACTIVITY OF THE AERIAL PARTS OF TEPHROSIA PURPUREA L.

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    Duraisami Nivedithadevi

    2012-03-01

    Full Text Available Tephrosia purpurea (Fabaceae has been used as a medicinal plant in all over India. This plant is a much branched perennial herb. Roots are given orally against any type of poisoning such as snakebite and the aerial parts were used for hydrophobia, asthma, cough, heart disease and kidney problems. Anti-microbial activity of 50% alcoholic extract with different concentrations were tested against the fungal strains like Aspergillus fumigates, Aspergillus niger, Ganoderma lucida and Candida albicans and bacterial organisms like Escherichia coli, Serratia mercescens, Staphylococcus aureus and Staphylococcus epidermis. The 50% alcoholic extract of Tephrosia purpurea at 5mg, 10mg, and 20mg concentration showed antibacterial activity against Escherichia coli, Serratia marcescens and Staphylococcus. Extracts of Tephrosia purpurea at 5mg, 10mg, and 20mg concentration did not show positive antifungal activities against Aspergillus fumigates, Aspergillus niger, Ganoderma lucida and Candida albicans. Antihistamine activity of 50% alcohol extract of Tephrosia purpurea (TP was evaluated in isolated guinea pig ileum. It was observed that different concentrations (2mg, 4mg and 8mg/ml of TP extract antagonized the contraction of ileum induced by histamine. The extracts at 8mg/ml concentration expected maximum antagonistic. The results obtained with histamine in guinea-pig isolated ileum preparations are sensitive to histamine against like histamine at the lower concentration.

  10. Inhibitory effect of aqueous extract of Echinacea purpurea and Nerium oleander on HSV-1 multiplication

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    Maliheh Farahani

    2014-02-01

    Full Text Available Background: Treatment of HSV-1 infections with the available chemical drugs may have some problems such as drug resistance and virus latency. Therefore, there is a requirement for new antiherpes drugs in today's world. The present study was carried out to analyze the inhibitory effect of Echinacea purpurea and Nerium oleander plants with ethnomedical background on HSV-1 replication. Methods: Plants were extracted by decoction method to obtain aqueous extract. These extracts were screened for their cytotoxicity against Hep-2 cell line by CPE (cytopathic effect assay. Antiviral effect of the plant extracts were determined by the virus cytopathic effect inhibition assay. Results: Nerium oleander extract had the highest toxicity (>0.1 μg/ml on Hep-2 cells and Echinacea purpurea extract exhibited significant antiherpes effect at nontoxic concentrations used on the cell lines. Findings indicated that Echinacea purpurea extract inhibited HSV-1 multiplication at concentrations >400 μg/ml. Conclusion: Echinacea purpurea plant had no any effect on cells at nontoxic concentrations and inhibited HSV-1 multiplication at concentrations >400 μg/ml. Further research is needed to find out the anti herpetic mechanism of this plant.

  11. Fractionation and evaluation of proteins in roots of Echinacea purpurea (L. Moench

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    Balciunaite Gabriele

    2015-12-01

    Full Text Available Echinacea purpurea (L. Moench, a member of the Asteraceae family, is a plant rich in flavonoids, essential oils, phenolic compounds, saponins, polysaccharides and glycoproteins. The aim of the study was to evaluate the protein content in dried roots of Echinacea purpurea (L. Moench after homogenization of roots with liquid nitrogen, extraction in 0.01 mol L-1 phosphate-buffered saline (PBS and purification followed by fractionation of proteins using gel filtration chromatography. Total concentration of proteins was measured using the Bradford method, and evaluation of the molecular mass of proteins was accomplished by applying the SDS-PAGE gel electrophoresis. The Bradford assay revealed that the highest concentration of proteins in fractions collected after gel filtration chomatography was 4.66–6.07 mg mL-1. Glycoproteins, alkamides and polysaccharides in roots of Echinacea purpurea (L. Moench are chemical compounds that are responsible for their immunomodulatory properties. However, information about the difference of protein contents in fresh and dried roots of E. purpurea is insufficient.

  12. Caffeic Acid Derivatives in Market Available Lamiaceae and Echinacea purpurea Products

    Science.gov (United States)

    Fresh basil leaves contain chicoric acid, the principal phenolic compound of Echinacea purpurea and purportedly the active ingredient in its dietary supplements. Our group discovered and first reported chicoric acid in basil. This following study examined the distribution of chicoric acid within the...

  13. Fractionation and evaluation of proteins in roots of Echinacea purpurea (L.) Moench.

    Science.gov (United States)

    Balciunaite, Gabriele; Juodsnukyte, Jovita; Savickas, Arunas; Ragazinskiene, Ona; Siatkute, Luka; Zvirblyte, Gitana; Mistiniene, Edita; Savickiene, Nijole

    2015-12-01

    Echinacea purpurea (L.) Moench, a member of the Asteraceae family, is a plant rich in flavonoids, essential oils, phenolic compounds, saponins, polysaccharides and glycoproteins. The aim of the study was to evaluate the protein content in dried roots of Echinacea purpurea (L.) Moench after homogenization of roots with liquid nitrogen, extraction in 0.01 mol L-1 phosphate-buffered saline (PBS) and purification followed by fractionation of proteins using gel filtration chromatography. Total concentration of proteins was measured using the Bradford method, and evaluation of the molecular mass of proteins was accomplished by applying the SDS-PAGE gel electrophoresis. The Bradford assay revealed that the highest concentration of proteins in fractions collected after gel filtration chomatography was 4.66-6.07 mg mL-1. Glycoproteins, alkamides and polysaccharides in roots of Echinacea purpurea (L.) Moench are chemical compounds that are responsible for their immunomodulatory properties. However, information about the difference of protein contents in fresh and dried roots of E. purpurea is insufficient.

  14. A C-banded karyotype of mitotic chromosomes in diploid purple coneflower (Echinacea purpurea L.).

    Science.gov (United States)

    Jiang, Weizhen; Li, Qingling; Chen, Xiaolu; Ren, Yi; Chen, Rong; Wu, Hong; Yang, Yuesheng

    2016-01-01

    Aneuploid ermpglasm is an important resource for genetic studies and identification of individual chromosomes in the cells of the aneuploid is an important step. The karyotype has already been established for purple coneflower (Echinacea purpurea L.), but due to the high similarity in the morphology of several pairs of chromosomes in this species, it cannot be used to identify individual chromosomes in its own complement. The objectives of this study are to develop and evaluate the Giemsa C-banding technique for the purpose of identifying the individual chromosomes in Echinacea purpurea. The established karyotype with C-bands showed that all the 11 pairs of chromosomes possessed centromeric bands. Telomeric bands appeared most frequently in almost all the chromosomes with only two exceptions, the short arm of the chromosome 9 and the long arm of the chromosome 10. Intercalary bands were found mainly in the long arm of some chromosomes with only two exceptions, the chromosomes 1 and 2 that had intercalary bands on both arms. The chromosome 4 was the only chromosome where intercalary bands were absent. Chromosomes in E. purpurea could be stained with Giemsa to bear C-bands. By classifying the chromosomes into groups and judging the C-bands, each chromosome could be identified. The methods established in this study might be used for the identification of chromosome constitution in aneuploid E. purpurea created in a breeding program.

  15. Diversity and biological activities of endophytic fungi associated with micropropagated medicinal plant Echinacea purpurea (L.) Moench

    Science.gov (United States)

    Echinacea is one of the top ten selling medicinal herbs in Europe and United States. Commercially available formulations may contain different plant parts of three species (Echinacea purpurea, E. pallida, and E. angustifolia). Our study evaluates the diversity of microbial community associated with ...

  16. Secondary Metabolites from Fungal Endophytes of Echinacea purpurea Suppress Cytokine Secretion by Macrophage-Type Cells.

    Science.gov (United States)

    Kaur, Amninder; Oberhofer, Martina; Juzumaite, Monika; Raja, Huzefa A; Gulledge, Travis V; Kao, Diana; Faeth, Stanley H; Laster, Scott M; Oberlies, Nicholas H; Cech, Nadja B

    2016-01-01

    Botanical extracts of Echinacea purpurea have been widely used for the treatment of upper respiratory infections. We sought to chemically examine fungal endophytes inhabiting E. purpurea, and to identify compounds produced by these endophytes with in vitro cytokine-suppressive activity. Twelve isolates from surface sterilized seeds of E. purpurea were subjected to fractionation and major components were isolated. Sixteen secondary metabolites belonging to different structural classes were identified from these isolates based on NMR and mass spectrometry data. The compounds were tested for their influence on cytokine secretion by murine macrophage-type cells. Alternariol (1), O-prenylporriolide (4), porritoxin (10) β-zearalenol (13), and (S)-zearalenone (14) inhibited production of TNF-α from RAW 264.7 macrophages stimulated with LPS in the absence of any significant cytotoxicity. This is the first report of a cytokine-suppressive effect for 4. The results of this study are particularly interesting given that they show the presence of compounds with cytokine-suppressive activity in endophytes from a botanical used to treat inflammation. Future investigations into the role of fungal endophytes in the biological activity of E. purpurea dietary supplements may be warranted.

  17. OVERCOMING SEED DORMANCY IN Annona macroprophyllata AND Annona purpureaUSING PLANT GROWTH REGULATORS

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    GISELA FERREIRA

    Full Text Available ABSTRACT Some Annonaceae seeds are known to exhibit dormancy mechanisms ranging from possible seed coat impermeability to physiological dormancy. Thus, the aim of this study was to evaluate the effects of gibberellin (GA GA3 and GA4+7 + benzyladenine (GA4+7 + BA application in seeds of Annona macroprophyllata Donn. Sm (papausa and Annona purpurea Moc. & Sessé ex Dunal (chincuya. The experiment was performed by the application of GA3 and GA4+7 + BA on seeds in concentrations of 0, 200, 400, 500, 600, 800 and 1000 mg L-1. The regulators broke the dormancy of both species. However, application of the GA4+7 + BA mixture had more significant results, with greater increases in germination in A. macroprophyllata than in A. purpurea. Treatments that promoted the highest germinations were GA4+7 + BA at a concentration of 200 mg L-1 for A. macroprophyllata (77% and 200 mg L-1 of GA4+7 + BA and 500 mg L-1 of GA3 for A. purpurea (30% and 29%, respectively. Rate index, mean time and frequency of germination were distinct for both species and both treatments. Although both GA3 and GA4+7 + BA promote germination, the GA4+7 + BA mixture was more effective than GA3 to overcoming seed dormancy of both species, A. purpurea has a harder dormancy than A. macroprophyllata

  18. The major Cu,Zn SOD of the phytopathogen Claviceps purpurea is not essential for pathogenicity

    NARCIS (Netherlands)

    Moore, S; De Vries, OMH; Tudzynski, P

    2002-01-01

    Superoxide dismutase (SOD) activities of the biotrophic pathogen Claviceps purpurea, which causes the ergot disease on a wide range of host grasses, were examined in axenic and pathogenic cultures. Almost all SOD activity in axenic culture originated from a single Cu,Zn SOD; a substantial part of th

  19. Comparative evaluation of the polyphenol composition and antioxidant capacity of propolis and Echinacea purpurea

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    Silviya S. Georgieva

    2014-02-01

    Full Text Available Objective: This study was undertaken to evaluate and compare total phenolics and total flavonoides, and antioxidant capacity of propolis and Echinacea purpurea ethanol extracts. Methods: Propolis and dried Echinacea purpurea extracts were obtained by extraction methods. The extracts were tested for total phenol and total flavonoid contents and antioxidant capacity was determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH assay. Results: The content of total phenolics and total flavonoids of propolis were found to be higher than Echinacea. The E.purpurea extract exhibited nearly 10 times lower antioxidant content in comparison with the propolis extracts. The 70% ethanol extract of propolis presented maximum antioxidant content, and the IC50 concentration was found to be higher in the 96% ethanol extract. However, both of the propolis extracts exhibited similar antioxidant activities. Conclusions: In the present study, the extracts of Echinacea purpurea and propolis were studied as sources of natural antioxidants. The results from the antioxidant assays show that all extracts can act as radical scavengers to a certain extent. They exhibit potent antioxidant activity in different solvent concentrations. Further studies in this area are in progress. [J Exp Integr Med 2014; 4(1.000: 51-56

  20. Final Programmatic Environmental Assessment for Test Area C-74 Complex, Eglin Air Force Base, Florida

    Science.gov (United States)

    2003-08-18

    Sarracenis purpurea Green Anole Anolis carolinensis Red Titi Cyrilla racemiflora Garter Snake Thamnophis sirtalis Tulip Poplar Liriodendrom... Tephrosia mohrii) Eglin’s open canopy Sandhills and upland pine forest Sweet Pitcher Plant (Sarracenia rubra) Wet flatwoods, wet prairies, and baygalls

  1. When attempts at robbing prey turn fatal.

    Science.gov (United States)

    Dejean, Alain; Corbara, Bruno; Azémar, Frédéric; Carpenter, James M

    2012-07-01

    Because group-hunting arboreal ants spread-eagle insect prey for a long time before retrieving them, these prey can be coveted by predatory flying insects. Yet, attempting to rob these prey is risky if the ant species is also an effective predator. Here, we show that trying to rob prey from Azteca andreae workers is a fatal error as 268 out of 276 potential cleptobionts (97.1 %) were captured in turn. The ant workers hunt in a group and use the "Velcro®" principle to cling firmly to the leaves of their host tree, permitting them to capture very large prey. Exceptions were one social wasp, plus some Trigona spp. workers and flies that landed directly on the prey and were able to take off immediately when attacked. We conclude that in this situation, previously captured prey attract potential cleptobionts that are captured in turn in most of the cases.

  2. Global stability of prey-taxis systems

    Science.gov (United States)

    Jin, Hai-Yang; Wang, Zhi-An

    2017-02-01

    In this paper, we prove the global boundedness and stability of the predator-prey system with prey-taxis in a two-dimensional bounded domain with Neumann boundary conditions. By deriving an entropy-like equality and a boundedness criterion, we show that the intrinsic interaction between predators and preys is sufficient to prevent the population overcrowding even the prey-taxis is included and strong. Furthermore, by constructing appropriate Lyapunov functionals, we show that prey-only steady state is globally asymptotically stable if the predation is weak, and the co-existence steady state is globally asymptotically stable under some conditions (like the prey-taxis is weak or the prey diffuses fast) if the predation is strong. The convergence rates of solutions to the steady states are derived in the paper.

  3. Prey pursuit and interception in dragonflies.

    Science.gov (United States)

    Olberg, R M; Worthington, A H; Venator, K R

    2000-02-01

    Perching dragonflies (Libellulidae; Odonata) are sit-and-wait predators, which take off and pursue small flying insects. To investigate their prey pursuit strategy, we videotaped 36 prey-capture flights of male dragonflies, Erythemis simplicicollis and Leucorrhinia intacta, for frame-by-frame analysis. We found that dragonflies fly directly toward the point of prey interception by steering to minimize the movement of the prey's image on the retina. This behavior could be guided by target-selective descending interneurons which show directionally selective visual responses to small-object movement. We investigated how dragonflies discriminate distance of potential prey. We found a peak in angular velocity of the prey shortly before take-off which might cue the dragonfly to nearby flying targets. Parallax information from head movements was not required for successful prey pursuit.

  4. D-Lysergyl peptide synthetase from the ergot fungus Claviceps purpurea.

    Science.gov (United States)

    Riederer, B; Han, M; Keller, U

    1996-11-01

    The ergot fungus Claviceps purpurea produces the medically important ergopeptines, which consist of a cyclol-structured tripeptide and D-lysergic acid linked by an amide bond. An enzyme activity capable of non-ribosomal synthesis of D-lysergyl-L-alanyl-L-phenylalanyl-L-proline lactam, the non-cyclol precursor of the ergopeptine ergotamine, has been purified about 18-fold from the ergotamine-producing C. purpurea strain D1. Analysis of radioactively labeled enzyme-substrate complexes revealed a 370-kDa lysergyl peptide synthetase 1 (LPS 1) carrying the amino acid activation domains for alanine, phenylalanine, and proline. The activation of D-lysergic acid is catalyzed by a 140-kDa peptide synthetase (LPS 2) copurifying with LPS 1. LPS 1 and LPS 2 contain 4'-phosphopantetheine and bind their substrates covalently by thioester linkage. Kinetic analysis of the synthesis reaction revealed a Km of approximately 1.4 microM for both D-lysergic acid and its structural homolog dihydrolysergic acid, which is one to two orders of magnitude lower than the Km values for the other amino acids involved. The Km values for the amino acids reflect their relative concentrations in the cellular pool of C. purpurea. This may indicate that in in vivo conditions D-lysergyl peptide formation is limited by the D-lysergic acid concentration in the cell. In vitro, the multienzyme preparation catalyzes the formation of several different D-lysergyl peptide lactams according to the amino acids supplied. Specific antiserum was used to detect LPS 1 in various C. purpurea strains. In C. purpurea wild type, the enzyme was expressed at all stages of cultivation and in different media, suggesting that it is produced constitutively.

  5. Effect of Echinacea purpurea on Control of Leishmania major Induced Cutaneous Leishmaniasis in Mice

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    MS Sadati

    2011-04-01

    Full Text Available Introduction & Objective: Leishmaniasis is a disease caused by intracellular protozoa parasites of the genus Leishmania and is endemic in some areas of Iran. Echinacea purpurea is a native plant from North America which is one of the most important medical herbs known with immuno-stimulant properties. This study was performed to determine the effect of alcoholic extract of Echinacea purpurea on prophylaxis and treatment of Leishmania cutaneous lesions. Materials & Methods: In this experimental study which was conducted at Shiraz University of Medical Sciences in 2009, eighteen mice were divided into 3 groups. Group one received Echinacea purpurea extract (200 mg/ml in their water, for 2 weeks before parasite injection, while group two were first injected with parasite amastigotes, followed by administration of Echinacea purpurea extract for 2 weeks. Group three was the control group, which received parasites, but not the extract. The size of Leishmania lesions in the tail base, right and left foot were measured with vernier caliper. The lesion areas were calculated and the collected data were analyzed with SPSS software. Results: The mean of lesion size in each group of mice were compared and analyzed. No significant differences in the lesions size were found between the three mice groups. Therefore, Echinacea purpurea extract was not effective against Leishmania major based on the findings of this study. Conclusion: Our findings suggest that Echinacea extract is not effective in treatment or prophylaxis of leishmaniasis in mice. Yet, further studies are needed to determine the effects of other extracts of this plant.

  6. Herb-drug interaction between Echinacea purpurea and etravirine in HIV-infected patients.

    Science.gov (United States)

    Moltó, José; Valle, Marta; Miranda, Cristina; Cedeño, Samandhy; Negredo, Eugenia; Clotet, Bonaventura

    2012-10-01

    The aim of this open-label, fixed-sequence study was to investigate the potential of the botanical supplement Echinacea purpurea to interact with etravirine, a nonnucleoside reverse transcriptase inhibitor of HIV. Fifteen HIV-infected patients receiving antiretroviral therapy with etravirine (400 mg once daily) for at least 4 weeks were included. E. purpurea root/extract-containing capsules were added to the antiretroviral treatment (500 mg every 8 h) for 14 days. Etravirine concentrations in plasma were determined by high-performance liquid chromatography immediately before and 1, 2, 4, 6, 8, 10, 12, and 24 h after a morning dose of etravirine on day 0 and etravirine plus E. purpurea on day 14. Individual etravirine pharmacokinetic parameters were calculated by noncompartmental analysis and compared between days 0 and 14 by means of the geometric mean ratio (GMR) and its 90% confidence interval (CI). The median age was 46 years (interquartile range, 41 to 50), and the median body weight was 76 kg (interquartile range, 68 to 92). Echinacea was well tolerated, and all participants completed the study. The GMR for etravirine coadministered with E. purpurea relative to etravirine alone was 1.07 (90% CI, 0.81 to 1.42) for the maximum concentration, 1.04 (90% CI, 0.79 to 1.38) for the area under the concentration-time curve from 0 to 24 h, and 1.04 (90% CI, 0.74 to 1.44) for the concentration at the end of the dosing interval. In conclusion, the coadministration of E. purpurea with etravirine was safe and well tolerated in HIV-infected patients; our data suggest that no dose adjustment for etravirine is necessary.

  7. Herb-Drug Interaction between Echinacea purpurea and Etravirine in HIV-Infected Patients

    Science.gov (United States)

    Valle, Marta; Miranda, Cristina; Cedeño, Samandhy; Negredo, Eugenia; Clotet, Bonaventura

    2012-01-01

    The aim of this open-label, fixed-sequence study was to investigate the potential of the botanical supplement Echinacea purpurea to interact with etravirine, a nonnucleoside reverse transcriptase inhibitor of HIV. Fifteen HIV-infected patients receiving antiretroviral therapy with etravirine (400 mg once daily) for at least 4 weeks were included. E. purpurea root/extract-containing capsules were added to the antiretroviral treatment (500 mg every 8 h) for 14 days. Etravirine concentrations in plasma were determined by high-performance liquid chromatography immediately before and 1, 2, 4, 6, 8, 10, 12, and 24 h after a morning dose of etravirine on day 0 and etravirine plus E. purpurea on day 14. Individual etravirine pharmacokinetic parameters were calculated by noncompartmental analysis and compared between days 0 and 14 by means of the geometric mean ratio (GMR) and its 90% confidence interval (CI). The median age was 46 years (interquartile range, 41 to 50), and the median body weight was 76 kg (interquartile range, 68 to 92). Echinacea was well tolerated, and all participants completed the study. The GMR for etravirine coadministered with E. purpurea relative to etravirine alone was 1.07 (90% CI, 0.81 to 1.42) for the maximum concentration, 1.04 (90% CI, 0.79 to 1.38) for the area under the concentration-time curve from 0 to 24 h, and 1.04 (90% CI, 0.74 to 1.44) for the concentration at the end of the dosing interval. In conclusion, the coadministration of E. purpurea with etravirine was safe and well tolerated in HIV-infected patients; our data suggest that no dose adjustment for etravirine is necessary. PMID:22869560

  8. Effects of flavonoids from Martynia annua and Tephrosia purpurea on cutaneous wound healing

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    Santram Lodhi

    2016-08-01

    Full Text Available Objective: Martynia annua L. (M. annua, (Martyniaccae has been traditionally used in the treatment of epilepsy, sore throat and inflammatory disorders. The leaf paste is used topically on Tuberculosis of the lymphatic glands and wounds of domestic animals. Tephrosia purpurea (T. purpurea, (Fabaceae has been used traditionally as a remedy for asthma, gonorrhea, rheumatism and ulcers. This study aimed to evaluate the potential wound healing effects of different fractions ofethanol extract of M. annua leaves and aerial parts of T. purpurea. Materials and Methods: Methanol fraction of M. annua (MAF-C and ethyl acetate fraction of T. purpurea (TPF-A were evaluated for healing potential in dead-space and burn wound models. An ointment (5% w/w of MAF-C and TPF-A, pongamol (0.2 and 0.5% w/w and luteolin (0.2 and 0.5% w/w was applied topically twice a day. The effects were compared with Povidone Iodine ointment with respect to protein, collagen content, enzymatic assay and histopathological finding of granuloma tissues. Results: Ethanol extracts of M. annua and T. purpureawere exhibited total flavonoid contents of 126.2 ± 4.69 and 171.6 ± 6.38 mg (quercetin equivalent, respectively. HPLC fingerprinting confirmed the presence of luteolin in M. annua and quercetin in T. purpurea. TPF-A and MAF-C ointments (5% w/w significantly increases the hydroxyproline and protein contents. Luteolin and pongamol ointments were also found to be effective in both wound models. Conclusion: Our findings suggested that 5% w/w ointment of TPF-A and MAF-C fractions were more effective than isolated flavonoids in wound healing which may be due to synergistic interactions between the flavonoids and other constituents.

  9. Effect of Aqueous Extract of Tephrosia purpurea on Cardiovascular Complications and Cataract Associated with Streptozotocin-induced Diabetes in Rats

    OpenAIRE

    Shraddha V Bhadada; Goyal, R. K.

    2015-01-01

    Tephrosia purpurea has been reported to possess antidiabetic activity, however, its effects on cardiovascular complications and cataract associated with diabetes have not been studied. The objective of the present study was to investigate the effects of aqueous extract of Tephrosia purpurea on cardiovascular complications and cataract associated with streptozotocin-induced diabetes in rats. Sprague Dawley rats of either sex were made diabetic with streptozotocin (45 mg/kg, i.v.). Treatment of...

  10. The effect of prey refuge in a patchy predator-prey system.

    Science.gov (United States)

    Ma, Zhihui; Wang, Shufan; Li, Weide; Li, Zizhen

    2013-05-01

    In this work, we proposed a patchy predator-prey model with one patch as refuge and the other as open habitat, and incorporated prey refuge in the considered model explicitly. We applied an analytical approach to study the dynamic consequences of the simplest forms of refuge used by prey and the migration efficiency. The results have shown that the refuge used by prey and the migration efficiency play an important role in the dynamic consequences of the interacting populations and the equilibrium density of two interacting populations. This work also proposed a new approach which can incorporate prey refuge in predator-prey system explicitly.

  11. Optimal forager against ideal free distributed prey.

    Science.gov (United States)

    Garay, József; Cressman, Ross; Xu, Fei; Varga, Zoltan; Cabello, Tomás

    2015-07-01

    The introduced dispersal-foraging game is a combination of prey habitat selection between two patch types and optimal-foraging approaches. Prey's patch preference and forager behavior determine the prey's survival rate. The forager's energy gain depends on local prey density in both types of exhaustible patches and on leaving time. We introduce two game-solution concepts. The static solution combines the ideal free distribution of the prey with optimal-foraging theory. The dynamical solution is given by a game dynamics describing the behavioral changes of prey and forager. We show (1) that each stable equilibrium dynamical solution is always a static solution, but not conversely; (2) that at an equilibrium dynamical solution, the forager can stabilize prey mixed patch use strategy in cases where ideal free distribution theory predicts that prey will use only one patch type; and (3) that when the equilibrium dynamical solution is unstable at fixed prey density, stable behavior cycles occur where neither forager nor prey keep a fixed behavior.

  12. Effects of phenytoin and Echinacea purpurea extract on proliferation and apoptosis of mouse embryonic palatal mesenchymal cells.

    Science.gov (United States)

    Hu, Xiao; Chen, Zhenguo; Mao, Xiaoyan; Tang, Shijie

    2011-05-01

    Cleft palate is one of the most common birth defects. Several environment factors are involved in the disorder, such as smoking, vitamin deficiency and teratogens. We investigated the teratogenic agent phenytoin and extract of the immunostimulant Echinacea purpurea in the etiology of cleft palate associated with the proliferation and apoptosis of mouse embryonic palatal mesenchymal (MEPM) cells. We measured the effects of phenytoin, E. purpurea extract, and the mixture of phenytoin and E. purpurea extract on the cell viability of MEPM cells by CCK-8 assay and on the proliferation and apoptosis of MEPM cells by BrdU labeling assay, flow cytometry, and TUNEL assay. Exposure to phenytoin for 24 h inhibited cell proliferation and increased cell apoptosis of MEPM cells, and E. purpurea extract had the reverse effect. Importantly, treatment with the mixture of phenytoin and E. purpurea extract increased the proliferation and decreased the apoptosis of MEPM cells as compared with treatment with phenytoin alone. The teratogenic effect of phenytoin on cleft palate is associated with the proliferation and apoptosis of MEPM cells, and E. purpurea extract may have a protective effect. Copyright © 2011 Wiley-Liss, Inc.

  13. Effect of aqueous extract of Tephrosia purpurea on cardiovascular complications and cataract associated with streptozotocin-induced diabetes in rats

    Directory of Open Access Journals (Sweden)

    Shraddha V Bhadada

    2015-01-01

    Full Text Available Tephrosia purpurea has been reported to possess antidiabetic activity, however, its effects on cardiovascular complications and cataract associated with diabetes have not been studied. The objective of the present study was to investigate the effects of aqueous extract of Tephrosia purpurea on cardiovascular complications and cataract associated with streptozotocin-induced diabetes in rats. Sprague Dawley rats of either sex were made diabetic with streptozotocin (45 mg/kg, i.v.. Treatment of aqueous extract of Tephrosia purpurea was given in the dose of 300 and 500 mg/kg/day, p.o for 8 weeks. Various hemodynamic (blood pressure, heart rate, +dp/dt, -dp/dt and biochemical (serum glucose, cholesterol, triglycerides, creatinine, urea, lactate dehydrogenase and creatinine kinase parameters were recorded after 8 weeks of the treatment. To evaluate cataract, various biochemical estimations were done in eye lens. Streptozotocin produced hyperglycemia; hypoinsulinemia; hyperlipidemia; increased blood pressure; increased creatinine, cardiac enzymes, reduction in heart rate and cardiac hypertrophy in rats and all these changes were prevented by the treatment with aqueous extract of Tephrosia purpurea in both the doses. Streptozotocin also produced decrease in soluble protein and reduced glutathione in lens of rats that was prevented by aqueous extract of Tephrosia purpurea. Our data suggest that aqueous extract of Tephrosia purpurea prevents not only the streptozotocin-induced metabolic abnormalities but also cardiovascular complications as well as reduce the risk of development of cataract.

  14. Effect of Aqueous Extract of Tephrosia purpurea on Cardiovascular Complications and Cataract Associated with Streptozotocin-induced Diabetes in Rats.

    Science.gov (United States)

    Bhadada, Shraddha V; Goyal, R K

    2015-01-01

    Tephrosia purpurea has been reported to possess antidiabetic activity, however, its effects on cardiovascular complications and cataract associated with diabetes have not been studied. The objective of the present study was to investigate the effects of aqueous extract of Tephrosia purpurea on cardiovascular complications and cataract associated with streptozotocin-induced diabetes in rats. Sprague Dawley rats of either sex were made diabetic with streptozotocin (45 mg/kg, i.v.). Treatment of aqueous extract of Tephrosia purpurea was given in the dose of 300 and 500 mg/kg/day, p.o for 8 weeks. Various hemodynamic (blood pressure, heart rate, +dp/dt, -dp/dt) and biochemical (serum glucose, cholesterol, triglycerides, creatinine, urea, lactate dehydrogenase and creatinine kinase) parameters were recorded after 8 weeks of the treatment. To evaluate cataract, various biochemical estimations were done in eye lens. Streptozotocin produced hyperglycemia; hypoinsulinemia; hyperlipidemia; increased blood pressure; increased creatinine, cardiac enzymes, reduction in heart rate and cardiac hypertrophy in rats and all these changes were prevented by the treatment with aqueous extract of Tephrosia purpurea in both the doses. Streptozotocin also produced decrease in soluble protein and reduced glutathione in lens of rats that was prevented by aqueous extract of Tephrosia purpurea. Our data suggest that aqueous extract of Tephrosia purpurea prevents not only the streptozotocin-induced metabolic abnormalities but also cardiovascular complications as well as reduce the risk of development of cataract.

  15. Coevolution can reverse predator-prey cycles.

    Science.gov (United States)

    Cortez, Michael H; Weitz, Joshua S

    2014-05-20

    A hallmark of Lotka-Volterra models, and other ecological models of predator-prey interactions, is that in predator-prey cycles, peaks in prey abundance precede peaks in predator abundance. Such models typically assume that species life history traits are fixed over ecologically relevant time scales. However, the coevolution of predator and prey traits has been shown to alter the community dynamics of natural systems, leading to novel dynamics including antiphase and cryptic cycles. Here, using an eco-coevolutionary model, we show that predator-prey coevolution can also drive population cycles where the opposite of canonical Lotka-Volterra oscillations occurs: predator peaks precede prey peaks. These reversed cycles arise when selection favors extreme phenotypes, predator offense is costly, and prey defense is effective against low-offense predators. We present multiple datasets from phage-cholera, mink-muskrat, and gyrfalcon-rock ptarmigan systems that exhibit reversed-peak ordering. Our results suggest that such cycles are a potential signature of predator-prey coevolution and reveal unique ways in which predator-prey coevolution can shape, and possibly reverse, community dynamics.

  16. Predators marked with chemical cues from one prey have increased attack success on another prey species

    NARCIS (Netherlands)

    van Maanen, R.; Broufas, G.; de Jong, P.; Aguilar-Fenollosa, E.; Revynthi, A.; Sabelis, M.W.; Janssen, A.

    2015-01-01

    1. To reduce the risk of being eaten by predators, prey alter their morphology or behaviour. This response can be tuned to the current danger if chemical or other cues associated with predators inform the prey about the risks involved. 2. It is well known that various prey species discriminate

  17. Optimal foraging on perilous prey : risk of bill damage reduces optimal prey size in oystercatchers

    NARCIS (Netherlands)

    Rutten, AL; Oosterbeek, K; Ens, Bruno J.; Verhulst, S

    2006-01-01

    Intake rate maximization alone is not. always sufficient in explaining prey size selection in predators. For example, bivalve-feeding oystercatchers regularly select. smaller prey than expected if they aimed to maximize their intake rat-C. It has been proposed that. to these birds large prey are

  18. Deterministic and Stochastic Analysis of a Prey-Dependent Predator-Prey System

    Science.gov (United States)

    Maiti, Alakes; Samanta, G. P.

    2005-01-01

    This paper reports on studies of the deterministic and stochastic behaviours of a predator-prey system with prey-dependent response function. The first part of the paper deals with the deterministic analysis of uniform boundedness, permanence, stability and bifurcation. In the second part the reproductive and mortality factors of the prey and…

  19. Modulation of liver enzymes by an Iranian preparation of Echinacea purpurea

    Directory of Open Access Journals (Sweden)

    A. Manayi

    2015-10-01

    Full Text Available Hepatitis B, a common infectious disease of liver, is transmitted by blood and body fluids like semen and vaginal fluid that carry hepatitis B virus (HBV.  In chronic infection, medical care is required to decrease possibility of cirrhosis and liver cancer. In the present report, the hepatoprotective effect of an Echinacea purpurea preparation (Echiherb® has been described in a patient who suffered from HBV infection. The levels of both enzymes of aspartate aminotransferase (AST and alanine aminotransferase (ALT decreased to their normal level after 6 weeks of treatment. Therefore, this report may provide a new perspective for protection of liver in patients with HBV infection along with other diseases which damage liver cells using E. purpurea preparations.

  20. The effect of Echinacea purpurea (L.) Moench extract on experimental prostate hyperplasia.

    Science.gov (United States)

    Skaudickas, D; Kondrotas, A J; Kevelaitis, E; Venskutonis, P R

    2009-10-01

    The aim of this study was to examine the effect of purple coneflower (Echinacea purpurea L. Moench) on the prostate gland of rats using an experimental model of benign prostate hyperplasia (BPH). The animals were administered 50 mg/kg of extract preparation for 4 and 8 weeks and the prostate mass and structural degenerative changes were evaluated in the course of the experiment. The administration of E. purpurea extract to rats with hyperplasia for 4 and 8 weeks gradually and significantly reduced the prostate mass and reversed the degenerative changes in the structure of the prostate gland. The present investigation suggests extract of purple coneflower prevents the development of BPH. (c) 2009 John Wiley & Sons, Ltd.

  1. Influence of Echinacea purpurea intake during pregnancy on fetal growth and tissue angiogenic activity.

    Directory of Open Access Journals (Sweden)

    Ewa Sommer

    2008-04-01

    Full Text Available The process of angiogenesis and control of blood vessels sprouting are fundamental to human health, as they play key roles in many physiological and pathological conditions. Intake of different pharmaceuticals with antiangiogenic activity by pregnant women may lead to severe developmental disturbances as it was described in case of thalidomide. It may also cause immunomodulatory effects as it was shown for antibiotics, theobromine, caffeic acid or catechins on the pregnant mice model. At present, Echinacea purpurea-based phytoceuticals are among the most popular herbals in the marketplace. Many compounds of Echinacea extracts (polysaccharides, alkamides, polyphenols, glycoproteins exert immunomodulatory, anti-oxidative and anti-inflammatory activity. Echinacea is one of the most powerful and effective remedies against many kinds of bacterial and viral infections. In previous studies we shown significant inhibitory effect of the Echinacea purpurea based remedy on tumour angiogenic activity using cutaneous angiogenesis test, and an inhibitory effect on L-1 sarcoma growth was observed . The aim of the present study was to establish whether pharmaceuticals containing alcoholic extracts of Echinacea purpurea given to pregnant mice influence angiogenic activity and tissue VEGF and bFGF production of their fetuses. We showed that angiogenic activity of tissue homogenates was increased in Esberitox group and diminished in case of Immunal forte as compared to standard diet group. In case of Echinapur group we did not find significant differences in angiogenic activity. VEGF and bFGF concentration were lower in all groups compared to the control. In the case of Echinapur and Esberitox number of fetuses in one litter were slightly lower as compared to control group, but the difference is on the border of statistical significance. In conclusion, there is some possibility that pharmaceuticals containing Echinacea purpurea might influence fetal development in

  2. Influence of Echinacea purpurea intake during pregnancy on fetal growth and tissue angiogenic activity.

    Science.gov (United States)

    Barcz, Ewa; Sommer, Ewa; Nartowska, Jadwiga; Balan, Barbara; Chorostowska-Wynimko, Joanna; Skopińska-Rózewska, Ewa

    2007-01-01

    The process of angiogenesis and control of blood vessels sprouting are fundamental to human health, as they play key roles in many physiological and pathological conditions. Intake of different pharmaceuticals with antiangiogenic activity by pregnant women may lead to severe developmental disturbances as it was described in case of thalidomide. It may also cause immunomodulatory effects as it was shown for antibiotics, theobromine, caffeic acid or catechins on the pregnant mice model. At present, Echinacea purpurea-based phytoceuticals are among the most popular herbals in the marketplace. Many compounds of Echinacea extracts (polysaccharides, alkamides, polyphenols, glycoproteins) exert immunomodulatory, anti-oxidative and anti-inflammatory activity. Echinacea is one of the most powerful and effective remedies against many kinds of bacterial and viral infections. In previous studies we shown significant inhibitory effect of the Echinacea purpurea based remedy on tumour angiogenic activity using cutaneous angiogenesis test, and an inhibitory effect on L-1 sarcoma growth was observed . The aim of the present study was to establish whether pharmaceuticals containing alcoholic extracts of Echinacea purpurea given to pregnant mice influence angiogenic activity and tissue VEGF and bFGF production of their fetuses. We showed that angiogenic activity of tissue homogenates was increased in Esberitox group and diminished in case of Immunal forte as compared to standard diet group. In case of Echinapur group we did not find significant differences in angiogenic activity. VEGF and bFGF concentration were lower in all groups compared to the control. In the case of Echinapur and Esberitox number of fetuses in one litter were slightly lower as compared to control group, but the difference is on the border of statistical significance. In conclusion, there is some possibility that pharmaceuticals containing Echinacea purpurea might influence fetal development in human also

  3. A new 1,2-ethanedione benzofurane derivative from Tephrosia purpurea.

    Science.gov (United States)

    Peng, Yan; Chen, Yinning; Gao, Chenghai; Yan, Tao; Cao, Wenhao; Huang, Riming

    2014-01-01

    A new 1,2-ethanedione benzofurane derivative, purpdione (1), was isolated from Tephrosia purpurea, together with seven known flavonoids, purpurenone (2), pongamol (3), ovalitenin A (4), karanjin (5), lanceolatin B (6), tachrosin (7) and villosinol (8). The new structure was elucidated based on the analysis of its spectroscopic data. The structures of the known compounds were identified by comparing their spectroscopic data with those reported in the literature. The isolates exhibited marginal ability to inhibit the settlement of barnacle (Balanus reticulatus).

  4. EVALUATION OF ANTIMICROBIAL AND ANTI-HISTAMINE ACTIVITY OF THE AERIAL PARTS OF TEPHROSIA PURPUREA L.

    OpenAIRE

    Duraisami Nivedithadevi; Paramasivam Manivannan; Ramamurthy Somasundaram

    2012-01-01

    Tephrosia purpurea (Fabaceae) has been used as a medicinal plant in all over India. This plant is a much branched perennial herb. Roots are given orally against any type of poisoning such as snakebite and the aerial parts were used for hydrophobia, asthma, cough, heart disease and kidney problems. Anti-microbial activity of 50% alcoholic extract with different concentrations were tested against the fungal strains like Aspergillus fumigates, Aspergillus niger, Ganoderma lucida and Candida alb...

  5. Influence of Echinacea purpurea intake during pregnancy on fetal growth and tissue angiogenic activity.

    Directory of Open Access Journals (Sweden)

    Joanna Chorostowska-Wynimko

    2008-04-01

    Full Text Available The process of angiogenesis and control of blood vessels sprouting are fundamental to human health, as they play key roles in many physiological and pathological conditions. Intake of different pharmaceuticals with antiangiogenic activity by pregnant women may lead to severe developmental disturbances as it was described in case of thalidomide. It may also cause immunomodulatory effects as it was shown for antibiotics, theobromine, caffeic acid or catechins on the pregnant mice model. At present, Echinacea purpurea-based phytoceuticals are among the most popular herbals in the marketplace. Many compounds of Echinacea extracts (polysaccharides, alkamides, polyphenols, glycoproteins exert immunomodulatory, anti-oxidative and anti-inflammatory activity. Echinacea is one of the most powerful and effective remedies against many kinds of bacterial and viral infections. In previous studies we shown significant inhibitory effect of the Echinacea purpurea based remedy on tumour angiogenic activity using cutaneous angiogenesis test, and an inhibitory effect on L-1 sarcoma growth was observed . The aim of the present study was to establish whether pharmaceuticals containing alcoholic extracts of Echinacea purpurea given to pregnant mice influence angiogenic activity and tissue VEGF and bFGF production of their fetuses. We showed that angiogenic activity of tissue homogenates was increased in Esberitox group and diminished in case of Immunal forte as compared to standard diet group. In case of Echinapur group we did not find significant differences in angiogenic activity. VEGF and bFGF concentration were lower in all groups compared to the control. In the case of Echinapur and Esberitox number of fetuses in one litter were slightly lower as compared to control group, but the difference is on the border of statistical significance. In conclusion, there is some possibility that pharmaceuticals containing Echinacea purpurea might influence fetal development in

  6. Evaluating the efficacy of cinnamaldehyde and Echinacea purpurea plant extract in broilers against Eimeria acervulina.

    Science.gov (United States)

    Orengo, J; Buendía, A J; Ruiz-Ibáñez, M R; Madrid, J; Del Río, L; Catalá-Gregori, P; García, V; Hernández, F

    2012-04-30

    Coccidiostats could be phased out as feed additives before 1 January 2013 for public health and food safety reasons, and, as a replacement, bioactive compounds found in plants are currently being investigated since they are more likely to be found acceptable by consumers. The aim of our study was to evaluate the effect of cinnamaldehyde (CIN) and Echinacea purpurea plant extract (EP) as additives by analyzing the performance traits, oocyst excretion and intestinal lesions following experimental infection with Eimeria acervulina. A total of 72 Ross male broilers were raised from 1 to 35 d and randomly assigned to four dietary treatments: control, without additives (C); 150 mg kg(-1) cinnamaldehyde (CIN); 1000 mg kg(-1)E. purpurea plant extract (EP); 150 mg kg(-1) cinnamaldehyde plus 1000 mg kg(-1)E. purpurea plant extract (CIN+EP). At 25 d, 12 chickens per treatment were orally infected with E. acervulina. Coccidia infestation led to lower performance but with no significant differences between the infected groups. Oocyst output reached its peak from 6 to 9 d post-infection in all treatments. At duodenal level, gross lesion scores were lower for cinnamaldehyde diets (P0.05). Scoring methods for macro- and microscopic lesions showed a positive linear relationship (G=+0.70). Further studies are necessary to assess the possible anticoccidian action of the cinnamaldehyde and its value as an alternative or adjunct in therapeutic or prophylactic strategies. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Anti-inflammatory effects of essential oil in Echinacea purpurea L.

    Science.gov (United States)

    Yu, Deqiang; Yuan, Yi; Jiang, Ling; Tai, Yuling; Yang, Xiumei; Hu, Fang; Xie, Zhongwen

    2013-03-01

    Echinacea purpurea L. is a medicinal plant originally from North America. It has become a commonly used herbal medicine worldwide because it contains various biologically active compounds. This study was designed to investigate the anti-inflammatory effects of essential oils from E. purpurea in both mice and rats. The extract was obtained from flower of E. purpurea by steam distillation. The anti-inflammatory potential was evaluated in vivo by using different animal models such as xylene-induced mouse ear edema, egg-white-induced rat paw edema, and cotton-induced granuloma tissue proliferating inflammation in mice. The serial dosages were used in vivo: the low dosage, the medium dosage and the high dosage. The low, medium and high dosages of extracts produced inhibitions of 39.24%, 47.22% and 44.79% respectively in the ear edema induced by xylene when compare with the control group. Only the high dosage group showed statistically significant inhibition (48.51%) of paw edema formation induced three hours by egg white compared with the control group (Ppurpurea have anti-inflammatory effects.

  8. Dietary Echinacea purpurea during murine pregnancy: effect on maternal hemopoiesis and fetal growth.

    Science.gov (United States)

    Chow, G; Johns, T; Miller, S C

    2006-01-01

    The medicinal benefits of Echinacea sp. plants in several disease conditions, including insect bites, respiratory ailments, and even cancer and AIDS, have been touted for decades. Echinacea sp.-based phytoceuticals are among the top selling herbals in the Western marketplace today. However, evidence is very scant concerning the effects of using Echinacea species herbals during pregnancy. While available data indicates that fetal malformations do not occur during pregnancy in humans consuming this herb, there are no formal studies aimed at assessing the possibility that consuming Echinacea herbals may promote spontaneous abortions, thereby reducing the number of live births upon which to assess the presence or absence of malformations. We undertook a study in which pregnant mice were fed daily Echinacea purpurea from pregnancy onset until gestational days 10, 11, 12, 13, and 14. Maternal spleen and bone marrow were taken for enumeration of cells in each of five separate hemopoietic lineages/organ, and fetal status was recorded. The data indicate that the significant, pregnancy-induced elevation in splenic lymphocytes and nucleated erythroid cells was all but eliminated in those females which consumed E. purpurea daily throughout their pregnancy. Moreover, consuming E. purpurea during pregnancy reduced the number of viable fetuses. The data may be extrapolated to suggest that in humans, abstention from consuming Echinacea products during the early/mid stages of pregnancy, may be prudent.

  9. Evaluation of Cichoric Acid of Echinacea purpurea Extract under Different Ecological Conditions in Semnan Province Iran

    Directory of Open Access Journals (Sweden)

    Elahe Rostami

    2015-02-01

    Full Text Available Echinacea purpurea is an herbaceous perennial plant as members of the Asteraceae family. It is one the important medicinal plant in pharmacy industrial. Active substances of Echinaceae are amplifier of body's immune system and antivirus. Echinacea is not native to Iran. The phytochemical traits of medicinal plants depend on ecological conditions involving growing areas, climate conditions; various grow stages and genetic modifications. The aim of this study was the evaluation of cichoric acid of E. purpurea extract in different ecological conditions in Semnan, Iran. Dormancy in seeds was broken by treating them with strafication in 4 °C for 48 h, was grown in nursery beds for autumn and early winter and transfered to four areas with different ecological conditions in late winter. Chashm, Ahuvan, Semnan and Foladmahale were chosen for this experiment. The spacing of plantlet was about 25 × 45 cm in the field. After 2- 3 months, aerial parts of the plants collected in all areas and extract samples were prepared and characterized using high- performance liquid chromatography (HPLC. The components of a basic HPLC system were shown significant values of the cichoric acid in plants under four habitats. The level of cichoric acid in one condition was more than standards level that reported in another references. In addition, ecological diversities have significant impacts the quantity of cichoric acid in E. purpurea.   

  10. Synergistic immunomopharmacological effects of N-alkylamides in Echinacea purpurea herbal extracts.

    Science.gov (United States)

    Chicca, Andrea; Raduner, Stefan; Pellati, Federica; Strompen, Thomas; Altmann, Karl-Heinz; Schoop, Roland; Gertsch, Jürg

    2009-07-01

    Echinacea purpurea extracts are used in the production of standardized herbal medicines for the prevention and treatment of upper respiratory infections. Unsaturated N-alkylamide lipids, the main constituent of E. purpurea and E. angustifolia preparations capable of activating the cannabinoid receptor type-2 (CB2) have been suggested to play a role as potential anti-inflammatory and immune-modulatory principles. Here we show that ethanolic E. purpurea radix and herba extracts produce synergistic pharmacological effects on the endocannabinoid system in vitro. Superadditive action of N-alkylamide combinations was seen at the level of intracellular calcium release as a function of CB2 receptor activation. Likewise, synergism of the radix and herba tinctures was observed in experiments measuring LPS-stimulated cytokine expression from human PBMCs. While the expression of the anti-inflammatory cytokine IL-10 was significantly superstimulated, the expression of the pro-inflammatory TNF-alpha protein was inhibited more strongly upon combination of the extracts. We show that N-alkylamides act in concert and exert pleiotropic effects modulating the endocannabinoid system by simultaneously targeting the CB2 receptor, endocannabinoid transport and degradation.

  11. Exploration of diuretic potential and electrolyte excretion of Tephrosia purpurea (Fabaceae) in rats.

    Science.gov (United States)

    Ashokkumar, D; Narayana, T V; Vidyasagar; Mazumder, Upal Kanti; Gupta, Malaya

    2012-03-01

    Tephrosia purpurea (Fabaceae) is a well-known traditional plant with diuretic effect but no scientific work published till date to support the claimed ethnomedical use. Therefore, the present study appraised the diuretic potential of methanol extract of Tephrosia purpurea (METP) in male wistar rats. The powdered plant material was extracted with methanol by hot extraction. The animals were divided into five groups for diuretic activity. The first group served as saline control (0.9%% saline solution, 25 ml/kg, body weight (b.w)), the second group received osmotic diuretic, urea (1 g/kg b.w), the third group received high-ceiling diuretic, furosemide (5 mg/kg b.w), and the other two groups were administered various concentrations of METP (200 mg/kg and 400 mg/kg b.w) orally to hydrated rats and their urine volume was measured at 5th and 24th hr after drug administration, while animals were deprived of food and water. After collection of urine, the parameters such as urine output, diuretic activity, electrolyte excretion of Na(++), K(++), Ca(2++), and Cl(-), and pH were analyzed. METP at various dose levels exhibited significant diuretic activity as evidenced by increased urine volume, electrolyte concentration, and alkaline pH in comparison to control group of animals. The present study provides a quantitative basis for explaining the folkloric use of Tephrosia purpurea as a diuretic agent in Indian traditional system of medicine.

  12. In vitro anti-inflammatory and xanthine oxidase inhibitory activity of Tephrosia purpurea shoot extract.

    Science.gov (United States)

    Nile, Shivraj H; Khobragade, Chandrahasy N

    2011-10-01

    The methanolic extract of Tephrosia purpurea (Leguminosae) shoots was evaluated in-vitro for its anti-inflammatory and xanthine oxidase inhibitory activity. Anti-inflammatory activity was measured by the Diene-conjugate, HET-CAM and beta-glucuronidase methods. The enzyme inhibitory activity was tested against isolated cow milk xanthine oxidase. The average anti-inflammatory activity of T. purpurea shoot extract in the concentration range of 1-2 microg/mL in the reacting system revealed significant anti-inflammatory activities, which, as recorded by the Diene-conjugate, HET-CAM and beta-glucuronidase assay methods, were 45.4, 10.5, and 70.5%, respectively. Screening of the xanthine oxidase inhibitory activity of the extract in terms of kinetic parameters revealed a mixed type of inhibition, wherein the Km and Vmax values in the presence of 25 to 100 microg/mL shoot extract was 0.20 mM/mL and 0.035, 0.026, 0.023 and 0.020 microg/min, while, for the positive control, the Km and Vmax values were 0.21 mM/mL and 0.043 microg/min, respectively. These findings suggest that T. purpurea shoot extract may possess constituents with good medicinal properties that could be exploited to treat the diseases associated with oxidative stress, xanthine oxidase enzyme activity and inflammation.

  13. Hepatoprotective activity of Tephrosia purpurea against arsenic induced toxicity in rats

    Directory of Open Access Journals (Sweden)

    Ravuri Halley Gora

    2014-01-01

    Full Text Available Aim: The present study was conducted to evaluate the hepatoprotective activity of Tephrosia purpurea (TP against sodium arsenite (NaAsO2 induced sub-acute toxicity in rats. Materials and Methods: Twenty four wistar albino rats of either sex were randomly divided into three groups. Group II and III were orally administered with sodium arsenite (10 mg/kg daily in drinking water for 28 days. Additionally Group III was orally treated with hydro-alcoholic extract of Tephrosia purpurea (TP @ 500 mg/kg daily for the same time period, whereas only deionized water was given to Group I (control. Serum biomarker levels, oxidative stress parameters and arsenic concentration were assessed in liver. Histopathology was also conducted. Results: It has been seen that TPE (500 mg/kg significantly (P < 0.01 reduced serum ALT, AST, ALP activity and increased total protein and reduced necrosis and inflammation in liver of group III compared to group II. A significantly (P < 0.01 higher LPO and lower GSH levels without change in SOD activity in liver was also observed in group II compared to group III, though there was no significant difference in arsenic accumulation between them. The plant extract also protects the animals of group III from significant (P < 0.01 reduction in body weight. Conclusion: Our study shows that supplementation of Tephrosia purpurea extract (500 mg/kg could ameliorate the hepatotoxic action of arsenic.

  14. Prey size spectra and prey availability of larval and small juvenile cod

    DEFF Research Database (Denmark)

    Munk, Peter

    1997-01-01

    stage when viewed on a relative predator/prey size scale. The study is based on stomach analysis of larval/juvenile cod in the size range 10-35 mm from nursery grounds in the North Sea. Stomach contents (species, size) were compared to environmental composition and preference indices were calculated...... prey biomass was highest in the areas of a hydrographic front, where larvae have been shown to concentrate. Changes in prey availability with larval growth depend strongly on specific prey biomass spectra at a given location. Both increasing and decreasing prey availability al increasing larval size...

  15. Inducible defenses in prey intensify predator cannibalism.

    Science.gov (United States)

    Kishida, Osamu; Trussell, Geoffrey C; Nishimura, Kinya; Ohgushi, Takayuki

    2009-11-01

    Trophic cascades are often a potent force in ecological communities, but abiotic and biotic heterogeneity can diffuse their influence. For example, inducible defenses in many species create variation in prey edibility, and size-structured interactions, such as cannibalism, can shift predator diets away from heterospecific prey. Although both factors diffuse cascade strength by adding heterogeneity to trophic interactions, the consequences of their interactioh remain poorly understood. We show that inducible defenses in tadpole prey greatly intensify cannibalism in predatory larval salamanders. The likelihood of cannibalism was also strongly influenced by asymmetries in salamander size that appear to be most important in the presence of defended prey. Hence, variation in prey edibility and the size structure of the predator may synergistically affect predator-prey population dynamics by reducing prey mortality and increasing predator mortality via cannibalism. We also suggest that the indirect effects of prey defenses may shape the evolution of predator traits that determine diet breadth and how trophic dynamics unfold in natural systems.

  16. Activities and prevalence of proteobacteria members colonizing Echinacea purpurea fully account for in vitro macrophage activation exhibited by extracts of this botanical

    Science.gov (United States)

    Evidence supports the theory that bacterial communities colonizing Echinacea purpurea contribute to the innate immune enhancing activity of this botanical. Previously we reported that only about half of the variation in in vitro monocyte stimulating activity exhibited by E. purpurea extracts could ...

  17. Predator-Prey Interactions in Communities with prey dispersal and Allee effects

    CERN Document Server

    Berezovskaya, F; Castillo-Chavez, C

    2009-01-01

    The population dynamics of predator-prey systems in the presence of patch-specific predators are explored in a setting where the prey population has access to both habitats. The emphasis is in situations where patch-prey abundance drives prey-dispersal between patches, with the fragile prey populations, that is, populations subject to the Allee effect. The resulting four-dimensional model's mathematical analysis is carried out via sub-models that focus in lower dimensional settings. The outcomes depend on, and in fact they are quite sensitive to, the structure of the system, the range of parameter values, and initial conditions. We show that the system can support multi-stability and a diverse set of predator-prey life-history dynamics that includes rather complex dynamical system outcomes. It is argued that in general evolution should favor heterogeneous settings including Allee effects, prey-refuges, and patch-specific predators.

  18. Permanence of Periodic Predator-Prey System with General Nonlinear Functional Response and Stage Structure for Both Predator and Prey

    Directory of Open Access Journals (Sweden)

    Xuming Huang

    2009-01-01

    Full Text Available We study the permanence of periodic predator-prey system with general nonlinear functional responses and stage structure for both predator and prey and obtain that the predator and the prey species are permanent.

  19. Evolutionary history of Purple cone spruce (Picea purpurea) in the Qinghai-Tibet Plateau: homoploid hybrid origin and Pleistocene expansion.

    Science.gov (United States)

    Sun, Yongshuai; Abbott, Richard J; Li, Lili; Li, Long; Zou, Jiabin; Liu, Jianquan

    2014-02-01

    Hybridization and introgression can play an important role in speciation. Here, we examine their roles in the origin and evolution of Picea purpurea, a diploid spruce species occurring on the Qinghai-Tibet Plateau (QTP). Phylogenetic relationships and ecological differences between this species and its relatives, P. schrenkiana, P. likiangensis and P. wilsonii, are unclear. To clarify them, we surveyed sequence variation within and between them for 11 nuclear loci, three chloroplast (cp) and two mitochondrial (mt) DNA fragments, and examined their ecological requirements using ecological niche modelling. Initial analyses based on 11 nuclear loci rejected a close relationship between P. schrenkiana and P. purpurea. BP&P tests and ecological niche modelling indicated substantial divergence between the remaining three species and supported the species status of P. purpurea, which contained many private alleles as expected for a well-established species. Sequence variation for cpDNA and mtDNA suggested a close relationship between P. purpurea and P. wilsonii, while variation at the nuclear se1364 gene suggested P. purpurea was more closely related to P. likiangensis. Analyses of genetic divergence, Bayesian clustering and model comparison using approximate Bayesian computation (ABC) of nuclear (nr) DNA variation all supported the hypothesis that P. purpurea originated by homoploid hybrid speciation from P. wilsonii and P. likiangensis. The ABC analysis dated the origin of P. purpurea at the Pleistocene, and the estimated hybrid parameter indicated that 69% of its nuclear composition was contributed by P. likiangensis and 31% by P. wilsonii. Our results further suggested that during or immediately following its formation, P. purpurea was subject to organelle DNA introgression from P. wilsonii such that it came to possess both mtDNA and cpDNA of P. wilsonii. The estimated parameters indicated that following its origin, P. purpurea underwent an

  20. Biological activity and phytochemical analysis of three Indonesian medicinal plants, Murraya koenigii, Syzygium polyanthum and Zingiber purpurea.

    Science.gov (United States)

    Kusuma, Irawan Wijaya; Kuspradini, Harlinda; Arung, Enos Tangke; Aryani, Farida; Min, Yu-Hong; Kim, Jin-Sook; Kim, Yong-ung

    2011-03-01

    Extracts of Indonesian medicinal plants, Murraya koenigii, Syzygium polyanthum, and Zingiber purpurea were investigated for their biological activity. The presence of phytochemicals, cytotoxicity, and antimicrobial and antioxidant activities were investigated. Parts of M. koenigii, S. polyanthum, and Z. purpurea were extracted with ethanol. The extracts were evaluated for antimicrobial activity using the disc diffusion method, while antioxidant activity was determined with a 1,1-diphenyl-2-picrylhydrazyl radical scavenging assay. Cytotoxicity was investigated using the brine shrimp lethality test, and phytochemical screening was performed using a standard method. M. koenigii leaf extract exhibited the most activity in the test microorganism activity index (AI), 0.38-1.25, when compared with standard drugs. S. polyanthum ripened fruit displayed significant antioxidant activity (90%) in comparison to ascorbic acid (95%). Z. purpurea rhizome extract possessed the highest cytotoxic effect with a LC(50) of 52 μg/mL. Phytochemical analysis revealed that carbohydrate, tannin, alkaloid, steroid, triterpenoid, and flavonoid were present in the extracts of M. koenigii leaves and twigs, S. polyanthum leaves and ripened and unripe fruits, and Z. purpurea rhizome, while saponin was only present in the S. polyanthum ripened fruit extract. Our work revealed that the M. koenigii leaves, S. polyanthum ripened fruit, and Z. purpurea rhizome extracts have potential as sources of new antimicrobial, antioxidant, and cytotoxic compounds, respectively.

  1. Alkamide Stability in Echinacea purpurea Extracts with and without Phenolic Acids in Dry Films and in Solution

    Science.gov (United States)

    Liu, Yi; Murphy, Patricia A.

    2007-01-01

    Degradation of the major alkamides in E. purpurea extracts was monitored under four different accelerated storage conditions, phenolic-depleted and phenolic-rich dry E. purpurea extracts and phenolic-depleted and phenolic-rich DMSO E. purpurea extracts at 70, 80, and 90 °C. Degradation of alkamides followed apparent first-order reaction rate kinetics. Alkamides degraded faster in dry films than in DMSO solution. The phenolic acids acted as antioxidants by limiting the loss of the alkamides in dry E. purpurea extracts. In contrast, E. purpurea alkamides in DMSO degraded faster when the phenolic fraction was absent. The overall order of degradation rate constants was alkamides 1 ≈ 2 ≈ 6 > 9 ≈ 8 > 3 ≈ 5 ≈ 7. The energy of activation (Ea) predicted for alkamide degradation averaged 101 ± 12 kJ/mol in dry films ± phenolic acids, suggesting the oxidation mechanism was the same under both conditions. In DMSO solutions, Ea values were about one-half of those in dry films (61 ± 14 kJ/mol), suggesting a different mechanism for alkamide oxidation in solution compared to dry. Predicted half-lives for alkamides in extracts suggested very good stability. PMID:17199322

  2. Activities and Prevalence of Proteobacteria Members Colonizing Echinacea purpurea Fully Account for Macrophage Activation Exhibited by Extracts of This Botanical.

    Science.gov (United States)

    Haron, Mona H; Tyler, Heather L; Pugh, Nirmal D; Moraes, Rita M; Maddox, Victor L; Jackson, Colin R; Pasco, David S

    2016-09-01

    Evidence supports the theory that bacterial communities colonizing Echinacea purpurea contribute to the innate immune enhancing activity of this botanical. Previously, we reported that only about half of the variation in in vitro monocyte stimulating activity exhibited by E. purpurea extracts could be accounted for by total bacterial load within the plant material. In the current study, we test the hypothesis that the type of bacteria, in addition to bacterial load, is necessary to fully account for extract activity. Bacterial community composition within commercial and freshly harvested (wild and cultivated) E. purpurea aerial samples was determined using high-throughput 16S rRNA gene pyrosequencing. Bacterial isolates representing 38 different taxa identified to be present within E. purpurea were acquired, and the activity exhibited by the extracts of these isolates varied by over 8000-fold. Members of the Proteobacteria exhibited the highest potency for in vitro macrophage activation and were the most predominant taxa. Furthermore, the mean activity exhibited by the Echinacea extracts could be solely accounted for by the activities and prevalence of Proteobacteria members comprising the plant-associated bacterial community. The efficacy of E. purpurea material for use against respiratory infections may be determined by the Proteobacterial community composition of this plant, since ingestion of bacteria (probiotics) is reported to have a protective effect against this health condition. Georg Thieme Verlag KG Stuttgart · New York.

  3. Natural association of two different betasatellites with Sweet potato leaf curl virus in wild morning glory (Ipomoea purpurea) in India.

    Science.gov (United States)

    Swapna Geetanjali, A; Shilpi, S; Mandal, Bikash

    2013-08-01

    Wild morning glory (Ipomoea purpurea) was observed to be affected by leaf curl and yellow vein diseases during summer-rainy season of 2009 in New Delhi, India. The virus was experimentally transmitted through whitefly, Bemisia tabaci to I. purpurea that reproduced the two distinct symptoms. Sequence analysis of multiple full-length clones obtained through rolling circle amplification from the leaf curl and yellow vein samples showed 91.8-95.3% sequence identity with Sweet potato leaf curl virus (SPLCV) and the isolates were phylogenetically distinct from those reported from Brazil, China, Japan and USA. Interestingly, two different betasatellites, croton yellow vein mosaic betasatellite and papaya leaf curl betasatellite were found with SPLCV in leaf curl and yellow vein diseases of I. purpurea, respectively. This study is the first report of occurrence of SPLCV in wild morning glory in India. SPLCV was known to infect other species of morning glory; our study revealed that I. purpurea, a new species of morning glory was a natural host of SPLCV. To date, betasatellite associated with SPLCV in Ipomoea spp. is not known. Our study provides evidence of natural association of two different betasatellites with SPLCV in leaf curl and yellow vein diseases of I. purpurea.

  4. [Simulation of Stipa purpurea distribution pattern on Tibetan Plateau based on MaxEnt model and GIS].

    Science.gov (United States)

    Hu, Zhong-jun; Zhang, Yi-li; Yu, Hai-bin

    2015-02-01

    The impact of climate change on species distribution is a hot issue in biogeography research. This study utilized the constructive species Stipa purpurea as the research object, which was widely distributed in alpine meadow of the Tibetan Plateau, investigated its distribution in the Tibetan Plateau through the field survey and herbarium search, and used MaxEnt model to simulate its historical, current and future distribution trends to analyze its distribution pattern in each historical period and explore the cause of species distribution changes. Research results showed that diversity of Stipa species in alpine grassland of the Tibetan Plateau was high, its main distribution area was the hinterland of the Tibetan Plateau and areas along the Himalaya, and its distribution was strongly affected by precipitation of warmest quarter, precipitation of wettest quarter and annual precipitation. According to the distribution pattern of S. purpurea in the Last Glacial Maximum, and geographical and geological features of the Tibetan Plateau, this paper proposed that: North Tibet core area of South Qiangtang and Ali region of west Himalaya mountainous area were the core area of the potential distribution for S. purpurea, since these regions could provide more suitable habitats for S. purpurea than other regions and be the refugia where the current S. purpurea was migrated and differentiated from. The presence of refugia may contribute to the understanding of related issues of the alpine plants' origin and differentiation in the Tibetan Plateau.

  5. The Epipolythiodiketopiperazine Gene Cluster in Claviceps purpurea: Dysfunctional Cytochrome P450 Enzyme Prevents Formation of the Previously Unknown Clapurines.

    Directory of Open Access Journals (Sweden)

    Julian Dopstadt

    Full Text Available Claviceps purpurea is an important food contaminant and well known for the production of the toxic ergot alkaloids. Apart from that, little is known about its secondary metabolism and not all toxic substances going along with the food contamination with Claviceps are known yet. We explored the metabolite profile of a gene cluster in C. purpurea with a high homology to gene clusters, which are responsible for the formation of epipolythiodiketopiperazine (ETP toxins in other fungi. By overexpressing the transcription factor, we were able to activate the cluster in the standard C. purpurea strain 20.1. Although all necessary genes for the formation of the characteristic disulfide bridge were expressed in the overexpression mutants, the fungus did not produce any ETPs. Isolation of pathway intermediates showed that the common biosynthetic pathway stops after the first steps. Our results demonstrate that hydroxylation of the diketopiperazine backbone is the critical step during the ETP biosynthesis. Due to a dysfunctional enzyme, the fungus is not able to produce toxic ETPs. Instead, the pathway end-products are new unusual metabolites with a unique nitrogen-sulfur bond. By heterologous expression of the Leptosphaeria maculans cytochrome P450 encoding gene sirC, we were able to identify the end-products of the ETP cluster in C. purpurea. The thioclapurines are so far unknown ETPs, which might contribute to the toxicity of other C. purpurea strains with a potentially intact ETP cluster.

  6. The Epipolythiodiketopiperazine Gene Cluster in Claviceps purpurea: Dysfunctional Cytochrome P450 Enzyme Prevents Formation of the Previously Unknown Clapurines

    Science.gov (United States)

    Tudzynski, Paul; Humpf, Hans-Ulrich

    2016-01-01

    Claviceps purpurea is an important food contaminant and well known for the production of the toxic ergot alkaloids. Apart from that, little is known about its secondary metabolism and not all toxic substances going along with the food contamination with Claviceps are known yet. We explored the metabolite profile of a gene cluster in C. purpurea with a high homology to gene clusters, which are responsible for the formation of epipolythiodiketopiperazine (ETP) toxins in other fungi. By overexpressing the transcription factor, we were able to activate the cluster in the standard C. purpurea strain 20.1. Although all necessary genes for the formation of the characteristic disulfide bridge were expressed in the overexpression mutants, the fungus did not produce any ETPs. Isolation of pathway intermediates showed that the common biosynthetic pathway stops after the first steps. Our results demonstrate that hydroxylation of the diketopiperazine backbone is the critical step during the ETP biosynthesis. Due to a dysfunctional enzyme, the fungus is not able to produce toxic ETPs. Instead, the pathway end-products are new unusual metabolites with a unique nitrogen-sulfur bond. By heterologous expression of the Leptosphaeria maculans cytochrome P450 encoding gene sirC, we were able to identify the end-products of the ETP cluster in C. purpurea. The thioclapurines are so far unknown ETPs, which might contribute to the toxicity of other C. purpurea strains with a potentially intact ETP cluster. PMID:27390873

  7. Prey preferences of the jaguar Panthera onca reflect the post-Pleistocene demise of large prey.

    Directory of Open Access Journals (Sweden)

    Matt W Hayward

    2016-01-01

    Full Text Available Documenting the impacts of the Pleistocene megafaunal extinctions on predator-prey interactions is a challenge because of the incomplete fossil record and depauperate extant community structure. We used a comparative ecological approach to investigate whether the existing prey preference patterns of jaguars Panthera onca were potentially affected by the Pleistocene extinctions in the Americas compared with large felids in Africa and Asia. We reviewed the literature and found 25 studies reporting 3214 jaguar kills recorded throughout the species’ distribution. We found that jaguars significantly preferred capybara Hydrochaeris hydrochaeris and giant anteater Myrmecophaga tridactyla, and avoided agoutis, carnivorans, primates, black-eared opossum Didelphis marsupialis and tapirs. Generalised linear models showed that jaguars select prey primarily based on socio-ecological and behavioural traits (abundance and herd size, rather than morphological characteristics (body size. Nonetheless, their accessible prey weight range was 6-60 kg, preferred prey weight range was 45-85 kg, and mean mass of significantly preferred prey was 32 ± 13 kg leading to a predator to prey body mass ratio of 1:0.53, which is much less than that of other solitary felids. Compared with other large, solitary felids, jaguars have an unusual predator to prey body mass ratio, show limited effect of prey morphology as a driver of prey selection, lack evidence of optimal foraging beyond their preferred prey, and an absence of preferentially hunting on Cetartiodactyla herbivores. These features, coupled with the reduction in jaguar body mass since the Pleistocene, suggest that the loss of larger potential prey items within the preferred and accessible weight ranges at the end-Pleistocene still affects jaguar predatory behaviour. It may be that jaguars survived this mass extinction event by preferentially preying on relatively small species.

  8. Isolation of chlorogenic acid from Mutellina purpurea L. herb using high-performance counter-current chromatography.

    Science.gov (United States)

    Sieniawska, Elwira; Skalicka-Woźniak, Krystyna

    2014-01-01

    The aim of the study was to explore proper isolation conditions of chlorogenic acid from the herb of Mutelina purpurea L. - a new source of this bioactive molecule. The accelerated solvent extraction (ASE) with 40% aqueous solution of methanol combined with high-performance counter-current chromatography (HPCCC) was utilised for the efficient extraction and the separation of chlorogenic acid from the M. purpurea herb in less than 30 min. The structure of the obtained compound was confirmed by mass spectrometry and NMR analysis. The preparative HPCCC was performed using the mixture of ethyl acetate, butanol and water (4:1:5, v/v/v) in the reverse-phase mode. The chlorogenic acid was isolated from this herb for the first time, yielding 96% purity. The ASE with 40% methanol combined with HPCCC separation was proven to be a useful tool for quick and efficient isolation of chlorogenic acid from M. purpurea.

  9. Gluttonous predators: how to estimate prey size when there are too many prey

    Directory of Open Access Journals (Sweden)

    MS. Araújo

    Full Text Available Prey size is an important factor in food consumption. In studies of feeding ecology, prey items are usually measured individually using calipers or ocular micrometers. Among amphibians and reptiles, there are species that feed on large numbers of small prey items (e.g. ants, termites. This high intake makes it difficult to estimate prey size consumed by these animals. We addressed this problem by developing and evaluating a procedure for subsampling the stomach contents of such predators in order to estimate prey size. Specifically, we developed a protocol based on a bootstrap procedure to obtain a subsample with a precision error of at the most 5%, with a confidence level of at least 95%. This guideline should reduce the sampling effort and facilitate future studies on the feeding habits of amphibians and reptiles, and also provide a means of obtaining precise estimates of prey size.

  10. The Dynamics of a Nonautonomous Predator-Prey Model with Infertility Control in the Prey

    Directory of Open Access Journals (Sweden)

    Xiaomei Feng

    2014-01-01

    Full Text Available A nonautonomous predator-prey model with infertility control in the prey is formulated and investigated. Threshold conditions for the permanence and extinction of fertility prey and infertility prey are established. Some new threshold values of integral form are obtained. For the periodic cases, these threshold conditions act as sharp threshold values for the permanence and extinction of fertility prey and infertility prey. There are also mounting concerns that the quantity of biological sterile drug is obtained in the process of the prevention and control of pest in the grasslands and farmland. Finally, two examples are given to illustrate the main results of this paper. The numerical simulations shown that, when the pest population is permanet, different dynamic behaviors may be found in this model, such as the global attractivity and the chaotic attractor.

  11. Effect of Echinacea purpurea (Asteraceae aqueous extract on antibody response to Bothrops asper venom and immune cell response

    Directory of Open Access Journals (Sweden)

    Fernando Chaves

    2007-03-01

    Full Text Available The effect of aqueous extract of Echinacea purpurea roots on the murine antibody response to Bothrops asper snake venom in vivo was studied. Three groups were used. Group #1, baseline control, was treated with snake venom plus PBS. Group #2 was treated with snake venom plus sodium alginate as adjuvant (routine method used at Instituto Clodomiro Picado, and group #3 or experimental group, was treated with snake venom plus aqueous extract of E. purpurea root as adjuvant. In all groups, the first inoculation was done with Freund’s complete adjuvant (FCA. By the time of the second bleeding, mice in group #3 showed a remarkable increment in the level of anti-venom antibodies compared with those in groups #1 or #2. In vitro immune cell proliferation as a response to aqueous extract of E. purpurea root was studied using human lymphocytes activated with different lectins (Con A, PHA and PWM. In all cases, increase in percentage of lymphoproliferation was greater when E. purpurea root extract was used in addition to individual lectins. Rev. Biol. Trop. 55 (1: 113-119. Epub 2007 March. 31.Se estudió in vivo, el efecto del extracto acuoso de las raíces de Echinacea purpurea en la respuesta de los anticuerpos murinos al veneno de la serpiente Bothrops asper. El grupo 1 control, fue tratado con el veneno y PBS. El grupo 2 con veneno y alginato de sodio (método utilizado en el Instituto Clodomiro Picado, y el grupo 3 o experimental, con veneno y extracto acuoso de las raíces de E. purpurea. En todos los grupos, la primera inmunización fue hecha con FCA (Freund’s Complete Adjuvant. En las muestras correspondientes a la segunda sangría, los ratones del grupo 3 mostraron un marcado incremento en el nivel de anticuerpos, en comparación con los ratones de los otros grupos. También se determinó la proliferación de células inmunes in vitro, como respuesta al extracto acuoso de la raíz de E. purpurea, utilizando linfocitos humanos activados con

  12. Prey-mediated avoidance of an intraguild predator by its intraguild prey.

    Science.gov (United States)

    Wilson, Ryan R; Blankenship, Terry L; Hooten, Mevin B; Shivik, John A

    2010-12-01

    Intraguild (IG) predation is an important factor influencing community structure, yet factors allowing coexistence of IG predator and IG prey are not well understood. The existence of spatial refuges for IG prey has recently been noted for their importance in allowing coexistence. However, reduction in basal prey availability might lead IG prey to leave spatial refuges for greater access to prey, leading to increased IG predation and fewer opportunities for coexistence. We determined how the availability of prey affected space-use patterns of bobcats (Lynx rufus, IG prey) in relation to coyote space-use patterns (Canis latrans, IG predators). We located animals from fall 2007 to spring 2009 and estimated bobcat home ranges and core areas seasonally. For each bobcat relocation, we determined intensity of coyote use, distance to water, small mammal biomass, and mean small mammal biomass of the home range during the season the location was collected. We built generalized linear mixed models and used Akaike Information Criteria to determine which factors best predicted bobcat space use. Coyote intensity was a primary determinant of bobcat core area location. In bobcat home ranges with abundant prey, core areas occurred where coyote use was low, but shifted to areas intensively used by coyotes when prey declined. High spatial variability in basal prey abundance allowed some bobcats to avoid coyotes while at the same time others were forced into more risky areas. Our results suggest that multiple behavioral strategies associated with spatial variation in basal prey abundance likely allow IG prey and IG predators to coexist.

  13. Coupled predator-prey oscillations in a chaotic food web

    NARCIS (Netherlands)

    Beninca, E.; Jöhnk, K.; Heerkloss, R.; Huisman, J.

    2009-01-01

    Coupling of several predator-prey oscillations can generate intriguing patterns of synchronization and chaos. Theory predicts that prey species will fluctuate in phase if predator-prey cycles are coupled through generalist predators, whereas they will fluctuate in anti-phase if predator-prey cycles

  14. Coupled predator-prey oscillations in a chaotic food web

    NARCIS (Netherlands)

    Benincà, E.; Johnk, K.D.; Heerkloss, R.; Huisman, J.

    2009-01-01

    Coupling of several predator-prey oscillations can generate intriguing patterns of synchronization and chaos. Theory predicts that prey species will fluctuate in phase if predator-prey cycles are coupled through generalist predators, whereas they will fluctuate in anti-phase if predator-prey cycles

  15. Evolution in predator-prey systems

    CERN Document Server

    Durrett, Rick

    2009-01-01

    We study the adaptive dynamics of predator prey systems modeled by a dynamical system in which the characteristics are allowed to evolve by small mutations. When only the prey are allowed to evolve, and the size of the mutational change tends to 0, the system does not exhibit long term prey coexistence and the parameters of the resident prey type converges to the solution of an ODE. When only the predators are allowed to evolve, coexistence of predators occurs. In this case, depending on the parameters being varied we see (i) the number of coexisting predators remains tight and the differences of the parameters from a reference species converge in distribution to a limit, or (ii) the number of coexisting predators tends to infinity, and we conjecture that the differences converge to a deterministic limit.

  16. Effects of the prey refuge distribution on a predator-prey system

    Science.gov (United States)

    Lee, Sang-Hee; Kwon, Ohsung; Song, Hark-Soo

    2016-03-01

    The existence of prey refuges in a predator-prey system is known to be strongly related to the ecosystem's stability. In this study, we explored how the prey refuge distribution affects the predator-prey system. To do so, we constructed a spatial lattice model to simulate an integrative predator (wolf) - prey (rabbit) - plant (grass) relationship. When a wolf (rabbit) encountered a rabbit (grass), the wolf (rabbit) tended to move to the rabbit (grass) for foraging while the rabbit tended to escape from the wolf. These behaviors were mathematically described by the degrees of willingness for hunting ( H) and escaping ( E). Initially, n refuges for prey were heterogeneously distributed in the lattice space. The heterogeneity was characterized as variable A. Higher values of A equate to higher aggregation in the refuge. We investigated the mean population density for different values of H, E, and A. To simply characterize the refuge distribution effect, we built an H-E grid map containing the population density for each species. Then, we counted the number of grids, N, with a population density ≥ 0.25. Simulation results showed that an appropriate value of A positively affected prey survival while values of A were too high had a negative effect on prey survival. The results were explained by using the trade-off between the staying time of the prey in the refuge and the cluster size of the refuge.

  17. Influence of predator mutual interference and prey refuge on Lotka-Volterra predator-prey dynamics

    Science.gov (United States)

    Chen, Liujuan; Chen, Fengde; Wang, Yiqin

    2013-11-01

    A Lotka-Volterra predator-prey model incorporating a constant number of prey using refuges and mutual interference for predator species is presented. By applying the divergency criterion and theories on exceptional directions and normal sectors, we show that the interior equilibrium is always globally asymptotically stable and two boundary equilibria are both saddle points. Our results indicate that prey refuge has no influence on the coexistence of predator and prey species of the considered model under the effects of mutual interference for predator species, which differently from the conclusion without predator mutual interference, thus improving some known ones. Numerical simulations are performed to illustrate the validity of our results.

  18. Beaked whales echolocate on prey.

    Science.gov (United States)

    Johnson, Mark; Madsen, Peter T; Zimmer, Walter M X; de Soto, Natacha Aguilar; Tyack, Peter L

    2004-12-01

    Beaked whales (Cetacea: Ziphiidea) of the genera Ziphius and Mesoplodon are so difficult to study that they are mostly known from strandings. How these elusive toothed whales use and react to sound is of concern because they mass strand during naval sonar exercises. A new non-invasive acoustic ording tag was attached to four beaked whales(two Mesoplodon densirostris and two Ziphius cavirostris) and recorded high-frequency clicks during deep dives. The tagged whales only clicked at depths below 200 m, down to a maximum depth of 1267 m. Both species produced a large number of short, directional, ultrasonic clicks with significant energy below 20 kHz. The tags recorded echoes from prey items; to our knowledge, a first for any animal echolocating in the wild. As far as we are aware, these echoes provide the first direct evidence on how free-ranging toothed whales use echolocation in foraging. The strength of these echoes suggests that the source level of Mesoplodon clicks is in the range of 200-220 dB re 1 microPa at 1 m. This paper presents conclusive data on the normal vocalizations of these beaked whale species, which may enable acoustic monitoring to mitigate exposure to sounds intense enough to harm them.

  19. Predator-prey molecular ecosystems.

    Science.gov (United States)

    Fujii, Teruo; Rondelez, Yannick

    2013-01-22

    Biological organisms use intricate networks of chemical reactions to control molecular processes and spatiotemporal organization. In turn, these living systems are embedded in self-organized structures of larger scales, for example, ecosystems. Synthetic in vitro efforts have reproduced the architectures and behaviors of simple cellular circuits. However, because all these systems share the same dynamic foundations, a generalized molecular programming strategy should also support complex collective behaviors, as seen, for example, in animal populations. We report here the bottom-up assembly of chemical systems that reproduce in vitro the specific dynamics of ecological communities. We experimentally observed unprecedented molecular behaviors, including predator-prey oscillations, competition-induced chaos, and symbiotic synchronization. These synthetic systems are tailored through a novel, compact, and versatile design strategy, leveraging the programmability of DNA interactions under the precise control of enzymatic catalysis. Such self-organizing assemblies will foster a better appreciation of the molecular origins of biological complexity and may also serve to orchestrate complex collective operations of molecular agents in technological applications.

  20. Beaked whales echolocate on prey.

    Science.gov (United States)

    Johnson, Mark; Madsen, Peter T; Zimmer, Walter M X; de Soto, Natacha Aguilar; Tyack, Peter L

    2004-01-01

    Beaked whales (Cetacea: Ziphiidea) of the genera Ziphius and Mesoplodon are so difficult to study that they are mostly known from strandings. How these elusive toothed whales use and react to sound is of concern because they mass strand during naval sonar exercises. A new non-invasive acoustic ording tag was attached to four beaked whales(two Mesoplodon densirostris and two Ziphius cavirostris) and recorded high-frequency clicks during deep dives. The tagged whales only clicked at depths below 200 m, down to a maximum depth of 1267 m. Both species produced a large number of short, directional, ultrasonic clicks with significant energy below 20 kHz. The tags recorded echoes from prey items; to our knowledge, a first for any animal echolocating in the wild. As far as we are aware, these echoes provide the first direct evidence on how free-ranging toothed whales use echolocation in foraging. The strength of these echoes suggests that the source level of Mesoplodon clicks is in the range of 200-220 dB re 1 microPa at 1 m.This paper presents conclusive data on the normal vocalizations of these beaked whale species, which may enable acoustic monitoring to mitigate exposure to sounds intense enough to harm them. PMID:15801582

  1. Herb-drug interaction between Echinacea purpurea and darunavir-ritonavir in HIV-infected patients.

    Science.gov (United States)

    Moltó, José; Valle, Marta; Miranda, Cristina; Cedeño, Samandhy; Negredo, Eugenia; Barbanoj, Manuel José; Clotet, Bonaventura

    2011-01-01

    The aim of this open-label, fixed-sequence study was to investigate the potential of Echinacea purpurea, a commonly used botanical supplement, to interact with the boosted protease inhibitor darunavir-ritonavir. Fifteen HIV-infected patients receiving antiretroviral therapy including darunavir-ritonavir (600/100 mg twice daily) for at least 4 weeks were included. E. purpurea root extract capsules were added to the antiretroviral treatment (500 mg every 6 h) from days 1 to 14. Darunavir concentrations in plasma were determined by high-performance liquid chromatography immediately before and 1, 2, 4, 6, 8, 10, and 12 h after a morning dose of darunavir-ritonavir on days 0 (darunavir-ritonavir) and 14 (darunavir-ritonavir plus echinacea). Individual darunavir pharmacokinetic parameters were calculated by noncompartmental analysis and compared between days 0 and 14 with the geometric mean ratio (GMR) and its 90% confidence interval (CI). The median age was 49 (range, 43 to 67) years, and the body mass index was 24.2 (range, 18.7 to 27.5) kg/m(2). Echinacea was well tolerated, and all participants completed the study. The GMR for darunavir coadministered with echinacea relative to that for darunavir alone was 0.84 (90% CI, 0.63-1.12) for the concentration at the end of the dosing interval, 0.90 (90% CI, 0.74-1.10) for the area under the concentration-time curve from 0 to 12 h, and 0.98 (90% CI, 0.82-1.16) for the maximum concentration. In summary, coadministration of E. purpurea with darunavir-ritonavir was safe and well tolerated. Individual patients did show a decrease in darunavir concentrations, although this did not affect the overall darunavir or ritonavir pharmacokinetics. Although no dose adjustment is required, monitoring darunavir concentrations on an individual basis may give reassurance in this setting.

  2. Herb-Drug Interaction between Echinacea purpurea and Darunavir-Ritonavir in HIV-Infected Patients▿

    Science.gov (United States)

    Moltó, José; Valle, Marta; Miranda, Cristina; Cedeño, Samandhy; Negredo, Eugenia; Barbanoj, Manuel José; Clotet, Bonaventura

    2011-01-01

    The aim of this open-label, fixed-sequence study was to investigate the potential of Echinacea purpurea, a commonly used botanical supplement, to interact with the boosted protease inhibitor darunavir-ritonavir. Fifteen HIV-infected patients receiving antiretroviral therapy including darunavir-ritonavir (600/100 mg twice daily) for at least 4 weeks were included. E. purpurea root extract capsules were added to the antiretroviral treatment (500 mg every 6 h) from days 1 to 14. Darunavir concentrations in plasma were determined by high-performance liquid chromatography immediately before and 1, 2, 4, 6, 8, 10, and 12 h after a morning dose of darunavir-ritonavir on days 0 (darunavir-ritonavir) and 14 (darunavir-ritonavir plus echinacea). Individual darunavir pharmacokinetic parameters were calculated by noncompartmental analysis and compared between days 0 and 14 with the geometric mean ratio (GMR) and its 90% confidence interval (CI). The median age was 49 (range, 43 to 67) years, and the body mass index was 24.2 (range, 18.7 to 27.5) kg/m2. Echinacea was well tolerated, and all participants completed the study. The GMR for darunavir coadministered with echinacea relative to that for darunavir alone was 0.84 (90% CI, 0.63-1.12) for the concentration at the end of the dosing interval, 0.90 (90% CI, 0.74-1.10) for the area under the concentration-time curve from 0 to 12 h, and 0.98 (90% CI, 0.82-1.16) for the maximum concentration. In summary, coadministration of E. purpurea with darunavir-ritonavir was safe and well tolerated. Individual patients did show a decrease in darunavir concentrations, although this did not affect the overall darunavir or ritonavir pharmacokinetics. Although no dose adjustment is required, monitoring darunavir concentrations on an individual basis may give reassurance in this setting. PMID:21078942

  3. In vitro antioxidant and cytotoxic potential of different parts of Tephrosia purpurea.

    Science.gov (United States)

    Padmapriya, Ramamoorthy; Ashwini, Sankar; Raveendran, Ramasamy

    2017-02-01

    The antioxidant and cytotoxic properties of four major parts of methanolic extracts of Tephrosia purpurea including leaves, root, stem and seed were investigated and compared. In vitro antioxidant activity of T. purpurea extracts was evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), reducing power assay and antihemolytic assay. In vitro cytotoxic effect of T. purpurea extracts on SW620 colorectal cancer cell line was studied using 3-(4, 5-dimethylthiazolyl -2,5-diphenyl-tetrazolium bromide (MTT) assay. Folin-ciocalteu and aluminium chloride methods were used to determine the total phenolic and flavonoid contents respectively. Among the four extracts studied, leaves extract showed the highest antioxidant activity, DPPH: 186.3 ± 14.0 μg/mL, FRAP: 754.2 ± 50.9 μmol Fe(II)/mg and reducing power activity: 65.7 ± 4.2 μg/mg of quercetin equivalent (QE/mg) and there was no significant difference observed in antihemolytic activity. Leaves extract showed effective cytotoxicity on colorectal cancer cells (IC50: 95.73 ± 9.6 μg/mL) and also had the higher total phenolic (90.5 ± 6.7 μg/mg of gallic acid equivalent (GAE/mg) and flavonoid content (21.8 ± 5.4 μg QE/mg). These results suggest higher antioxidant and cytotoxic activities of leaves extract in comparison with other extracts and these activities could be due to the presence of rich phenolic and flavonoid content.

  4. In vitro antioxidant and cytotoxic potential of different parts of Tephrosia purpurea

    Directory of Open Access Journals (Sweden)

    Ramamoorthy Padmapriya

    2017-01-01

    Full Text Available The antioxidant and cytotoxic properties of four major parts of methanolic extracts of Tephrosia purpurea including leaves, root, stem and seed were investigated and compared. In vitro antioxidant activity of T. purpurea extracts was evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH, ferric reducing antioxidant power (FRAP, reducing power assay and antihemolytic assay. In vitro cytotoxic effect of T. purpurea extracts on SW620 colorectal cancer cell line was studied using 3-(4, 5-dimethylthiazolyl -2,5-diphenyl-tetrazolium bromide (MTT assay. Folin-ciocalteu and aluminium chloride methods were used to determine the total phenolic and flavonoid contents respectively. Among the four extracts studied, leaves extract showed the highest antioxidant activity, DPPH: 186.3 ± 14.0 μg/mL, FRAP: 754.2 ± 50.9 μmol Fe(II/mg and reducing power activity: 65.7 ± 4.2 μg/mg of quercetin equivalent (QE/mg and there was no significant difference observed in antihemolytic activity. Leaves extract showed effective cytotoxicity on colorectal cancer cells (IC 50 : 95.73 ± 9.6 μg/mL and also had the higher total phenolic (90.5 ± 6.7 μg/mg of gallic acid equivalent (GAE/mg and flavonoid content (21.8 ± 5.4 μg QE/mg. These results suggest higher antioxidant and cytotoxic activities of leaves extract in comparison with other extracts and these activities could be due to the presence of rich phenolic and flavonoid content.

  5. Effect of Tephrosia purpurea (L.) Pers. Leaves on Gentamicin-Induced Nephrotoxicity in Rats.

    Science.gov (United States)

    Jain, Avijeet; Nahata, Alok; Singhai, Abhay Kumar

    2013-01-01

    The aim of the study was to evaluate the nephroprotective and nephrocurative effects of Tephrosia purpurea (L.) Pers. leaves against gentamicin-induced acute renal injury in albino rats. The maximum free radical scavenging activity of the ethanolic extract was the basis for the selection of this extract for the in vivo study. Gentamicin (40 mg/kg, s.c.) was administered to induce toxicity in the toxic group and the ethanolic extract (200 mg/kg p.o.) was administered in all treated groups. Blood urea and serum creatinine levels were monitored to assess the effects. The antioxidant potential was also evaluated by the estimation of reduced glutathione (GSH) and malondialdehyde (MDA). Gentamicin intoxication caused significant increases in blood urea and serum creatinine levels as compared to the normal control. In the preventive regimen, the extract (200 mg/kg, p.o.) showed significant reductions in the elevated blood urea and serum creatinine. Histopathological changes were in accordance with the biochemical findings. Also in the curative regimen, the blood urea and serum creatinine levels revealed significant curative effects. In our in vivo antioxidant activity, the GSH level was significantly (PTephrosia purpurea leaves possesses marked nephroprotective and curative activities without any toxicity. The proposed mechanisms for the claimed activity are antioxidant activity and the inhibition of an overproduction of NO and Cox-2 expression. These activities may be attributed to the presence of phenolics and flavonoidal compounds like rutin and quercetin. Thus, it can be said that Tephrosia purpurea could offer a promising role in the treatment of acute renal injury caused by nephrotoxins like gentamicin.

  6. Ameliorative potential of Tephrosia purpurea extract against arsenic induced toxicity in wistar rats

    OpenAIRE

    Birendra kumar Roy; Naveen Kumar; Reetu Toppo; Priscilla Kerketta; Sushma Lalita Baxla; Ravuri Halley Gora

    2013-01-01

    Aim: The present investigation has been conducted to evaluate the protective activity of Tephrosia purpurea extract (TPE) against arsenic induced toxicity. Materials and Methods: For this study, twenty four wistar albino rats were taken. Control group, group – I rats were given sodium arsenite @ 10 mg/kg and group – II rats were treated with TPE @ 500 mg/kg along with sodium arsenite @ 10 mg/kg (daily oral for 28 days). On 29th day animals were slaughtered and various parameters were determin...

  7. Primeiro registro de Myriastra purpurea (Ridley, 1884 para a costa brasileira (Porifera, Demospongiae

    Directory of Open Access Journals (Sweden)

    Beatriz Mothes de Moraes

    1984-01-01

    Full Text Available The first record of occurrence of Myriastra purpurea (Ridley, 1884 for the South Atlantic Ocean at shallow areas of the Brazilian coast (State of Rio de Janeiro, Sepetiba Bay: 23º04'53"/44º00'34"W and State of Santa Catarina, Porto Belo: 27º09'12"S/48º29'30"W widely enlarges the distribution of the species, known only from the Indo-Pacific region. Detailed descriptions and ilustrations of the specimens are offered. A table of micrometric measurements and camera lucida drawings of spicules is also offered.

  8. Effect of Tephrosia purpurea (L.) Pers. Leaves on Gentamicin-Induced Nephrotoxicity in Rats

    OpenAIRE

    JAIN, Avijeet; NAHATA, Alok; SINGHAI, Abhay

    2013-01-01

    The aim of the study was to evaluate the nephroprotective and nephrocurative effects of Tephrosia purpurea (L.) Pers. leaves against gentamicin-induced acute renal injury in albino rats. The maximum free radical scavenging activity of the ethanolic extract was the basis for the selection of this extract for the in vivo study. Gentamicin (40 mg/kg, s.c.) was administered to induce toxicity in the toxic group and the ethanolic extract (200 mg/kg p.o.) was administered in all treated groups. Blo...

  9. In vitro antioxidant studies of the ethanolic extract of Tephrosia purpurea L.

    Science.gov (United States)

    Choudhary, G P

    2007-07-01

    The ethanolic extract of the root of Tephrosia purpurea was screened for in vitro antioxidant properties using standard procedures. The ethanolic extract exhibited IC(50) values of 132.31±8.79 and 405.22±15.09 respectively in DPPH and nitric acid radical inhibition assay. These values were slightly more than those obtained for ascorbic acid and rutin used as standard. The findings justify the therapeutic application of the plant in the indigenous system of medicine, augmenting its therapeutic value.

  10. In vitro antioxidant studies of the ethanolic extract of Tephrosia purpurea L.

    OpenAIRE

    Choudhary, G.P.

    2007-01-01

    The ethanolic extract of the root of Tephrosia purpurea was screened for in vitro antioxidant properties using standard procedures. The ethanolic extract exhibited IC50 values of 132.31±8.79 and 405.22±15.09 respectively in DPPH and nitric acid radical inhibition assay. These values were slightly more than those obtained for ascorbic acid and rutin used as standard. The findings justify the therapeutic application of the plant in the indigenous system of medicine, augmenting its therapeutic v...

  11. Restructuring fundamental predator-prey models by recognising prey-dependent conversion efficiency and mortality rates.

    Science.gov (United States)

    Li, Jiqiu; Montagnes, David J S

    2015-05-01

    Incorporating protozoa into population models (from simple predator-prey explorations to complex food web simulations) is of conceptual, ecological, and economic importance. From theoretical and empirical perspectives, we expose unappreciated complexity in the traditional predator-prey model structure and provide a parsimonious solution, especially for protistologists. We focus on how prey abundance alters two key components of models: predator conversion efficiency (e, the proportion of prey converted to predator, before mortality loss) and predator mortality (δ, the portion of the population lost though death). Using a well-established model system (Paramecium and Didinium), we collect data to parameterize a range of existing and novel population models that differ in the functional forms of e and δ. We then compare model simulations to an empirically obtained time-series of predator-prey population dynamics. The analysis indicates that prey-dependent e and δ should be considered when structuring population models and that both prey and predator biomass also vary with prey abundance. Both of these impact the ability of the model to predict population dynamics and, therefore, should be included in theoretical model evaluations and assessment of ecosystem dynamics associated with biomass flux.

  12. How the Magnitude of Prey Genetic Variation Alters Predator-Prey Eco-Evolutionary Dynamics.

    Science.gov (United States)

    Cortez, Michael H

    2016-09-01

    Evolution can alter the stability and dynamics of ecological communities; for example, prey evolution can drive cyclic dynamics in predator-prey systems that are not possible in the absence of evolution. However, it is unclear how the magnitude of additive genetic variation in the evolving species mediates those effects. In this study, I explore how the magnitude of prey additive genetic variation determines what effects prey evolution has on the dynamics and stability of predator-prey systems. I use linear stability analysis to decompose the stability of a general eco-evolutionary predator-prey model into components representing the stabilities of the ecological and evolutionary subsystems as well as the interactions between those subsystems. My results show that with low genetic variation, the cyclic dynamics and stability of the system are determined by the ecological subsystem. With increased genetic variation, disruptive selection always destabilizes stable communities, stabilizing selection can stabilize or destabilize communities, and prey evolution can alter predator-prey phase lags. Stability changes occur approximately when the magnitude of genetic variation balances the (in)stabilities of the ecological and evolutionary subsystems. I discuss the connections between my stability results and prior results from the theory of adaptive dynamics.

  13. Periodic Solutions of a Delayed Predator-Prey Model with Stage Structure for Prey

    Institute of Scientific and Technical Information of China (English)

    Rui Xu; Lan-sun Chen; Fei-long Hao

    2004-01-01

    A periodic predator-prey model with stage structure for prey and time delays due to negative feedbackand gestation of predator is proposed. By using Gaines and Mawhin's continuation theorem of coincidencedegree theory, su.cient conditions are derived for the existence of positive periodic solutions to the proposedmodel. Numerical simulations are presented to illustrate the feasibility of our main result.

  14. Molecular phylogeny, diversity and bioprospecting of endophytic fungi associated with wild ethnomedicinal North American plant Echinacea purpurea (Asteraceae)

    Science.gov (United States)

    The endophytic fungal community associated with the wild ethnomedicinal North American plant Echinacea purpurea was investigated as well as its potential for providing antifungal compounds against plant pathogenic fungi. A total of 233 endophytic fungal isolates were obtained and classified into 42 ...

  15. Study the Effect of Echinacea Purpurea Extract on Cellular Delayed Type Hypersensitivity and Splenocyte Proliferation in BALB/c Mice

    Directory of Open Access Journals (Sweden)

    Z.M. Hassan

    2008-01-01

    Full Text Available Objective: Purple cone flower plant (Echinacea purpurea is one of the mostimportant Herbal products in many countries. Up to now a lot of experimentsdemonstrated the controversial effects of this herb on immune system . In thisresearch we study the in vivo and in vitro effect of Iranian E.purpurea extract oncellular immunity.Materials and Methods: At first we determined the lethal dose of E.purpurea extract after intraperitoneal injection in BALB/c mice. Then we made five groups of mice and treat them by four times intraperitoneal injection of 1 ml extract at different doses (0, 0.4, 2, 10 and 50 mg/ml during two weeks. Splenocyte proliferation response to extract was assessed by MTT method. Delayed-Type Hypersensitivity (DTHresponse was evaluated by priming mice with 1×108 Sheep Red Blood Cell (SRBC injected subcutaneously in the back on day 7after treatment.Results: As a result no significant variation in weight and spleen index of test groups to control was observed. Splenocyte proliferation and DTH response of test groups to control increased significantly (p<0.05.Conclusion: However these data confirmed the results of previous studies, inaddition presented the first results about significant increase in DTH response that could not be seen before. Scince the main reason of this difference refers to active compounds of herb extract, comparing effective component of this extract with that of E.purpurea cultivated in other geographical condition will consider as the next studies.

  16. Cloning, characterization, and targeted disruption of cpcat1, coding for an in planta secreted catalase of Claviceps purpurea.

    Science.gov (United States)

    Garre, V; Müller, U; Tudzynski, P

    1998-08-01

    Claviceps purpurea has been shown to secrete catalases in axenic and parasitic culture. In order to determine the importance of these enzymes in the host-parasite interaction, especially their role in overcoming oxidative stress imposed on the pathogen by the plant's defense system, the catR gene from A. niger was used to isolate a putative catalase gene from a genomic library of C. purpurea, cpcat1 consists of an open reading frame of 2,148 bp that is interrupted by five introns. Its derived gene product shows significant homology to fungal catalases and contains a putative signal peptide of 19 amino acids and three putative N-glycosylation sites, which indicates that CPCAT1 is a secreted catalase. Disruption of the gene by a gene replacement approach resulted in the loss of two catalase isoforms, CATC and CATD, strongly suggesting that they are both encoded by cpcat1. CATD is the major secreted catalase of C. purpurea and is furthermore the only catalase present in the honeydew of infected rye ears. Deletion mutants of cpcat1 were inoculated on rye plants and showed no significant reduction in virulence. Ovarian tissue and honeydew of plants inoculated with the mutants lacked CATD, confirming that this catalase is not essential for colonization of the host tissue by C. purpurea.

  17. Evaluation of immunopathologic effects of aqueous extract of Echinacea purpurea in mice after experimental challenge with Pasteurella multocida serotype A.

    Science.gov (United States)

    Rezaie, A; Gharibi, D; Ghorbanpoor, M; Anbari, S; Pourmahdi Broojeni, M

    2014-01-01

    In order to assess the immunopathological effects of aqueous Echinacea purpurea extract (EPE) on mice experimentally challenged with Pasteurella multocida serotype A, forty female BALB/c mice were randomly divided into four groups. The groups included a control group (received sterile distilled water 2 times/week for 2 weeks, intraperitoneally and then 100 µl sterile saline intranasally), a PMA group (received sterile distilled water as the control group and after 2 weeks, 5.6 × 10(3) CFU/ml of P. multocida serotype A, intranasally), an EPE+PMA group (received E. purpurea extract intraperitoneally 2 times/week for 2 weeks and then challenged as the PMA group) and an EPE group (received E. purpurea extract as EPE+PMA group and then 100 µl sterile saline intranasally). After 24 and 48 h post challenge, half of the animals in each group were sacrificed and analyzed for bacterial counts in their lungs and livers, TNFα serum levels and histapathological changes. The results showed significant differences in lung bacterial counts between PMA and EPE+PMA groups. TNFα serum level was significantly higher in the PMA group. Histopathological examination revealed infiltration of neutrophils in alveolar septa and hyperemia in the PMA group. In addition, the criteria of bronchopneumonia were partially recovered in the EPE+PMA compared to the PMA group. According to the results, it seems that E. purpurea extract has an immunomodulatory effect and can be used to prevent or control of pneumonia caused by Pasteurella.

  18. Effects of extracts from Echinacea purpurea (L) MOENCH on mice infected with different strains of Toxoplasma gondii.

    Science.gov (United States)

    Gasparotto Junior, Arquimedes; Cosmo, Maria Luiza Antonio; Reis, Michelle de Paula; Dos Santos, Pamela Secundo; Gonçalves, Daniela Dib; Gasparotto, Francielly Mourão; Navarro, Italmar Teodorico; Lourenço, Emerson Luiz Botelho

    2016-10-01

    In recent years, due to the growing concern about recurrent epidemics by Toxoplasma gondii and other pathogens in Brazil, there has been an increase in the use of different preparations obtained from Echinacea purpurea in order to test their effectiveness against these infections. Although studies have suggested the beneficial effects of this species against the influenza virus, no data are available on the use of E. purpurea aqueous extract in T. gondii infections. Thus, the aim of this study was to analyze the effect of its administration in Swiss mice submitted to acute and prolonged infection with different T. gondii strains. This study showed that E. purpurea extract induced a significant reduction in the number of tachyzoites in the peritoneal fluid and liver imprints from mice infected by the RH strain. Moreover, prolonged treatment significantly increased the number of brain cysts of animals infected with ME 49 strain. The results obtained in this study suggest that the crude extract obtained from E. purpurea has important protective activities against infection with different T. gondii strains.

  19. Seasonal variations in the concentrations of lipophilic compounds and phenolic acids in the roots of Echinacea purpurea and Echinacea pallida.

    Science.gov (United States)

    Thomsen, Maria O; Fretté, Xavier C; Christensen, Kathrine B; Christensen, Lars P; Grevsen, Kai

    2012-12-12

    Roots of Echinacea purpurea and Echinacea pallida cultivated for 4 years in a North European climate were analyzed for seasonal variations in the concentrations of lipophilic constituents (alkamides, ketoalkenes, and ketoalkynes) and phenolic acids by harvesting five times during 1 year to establish the optimal time for harvest. A total of 16 alkamides, three ketoalkenes, two ketoalkynes, and four phenolic acids (echinacoside, cichoric acid, caftaric acid, and chlorogenic acid) were identified in aqueous ethanolic (70%) extracts by liquid chromatography-mass spectrometry and quantified by reverse-phase high-performance liquid chromatography. The major alkamides in the roots of E. purpurea were at their lowest concentration in the middle of autumn and early winter, and the total concentration of lipophilic compounds in E. pallida showed the same pattern. Moreover, all of the major phenolic acids in E. purpurea were at their highest concentrations in spring. The optimal harvest time in spring is in contrast to normal growing guidelines; hence, this specific information of seasonal variations in the concentrations of lipophilic and phenolic compounds in E. purpurea and E. pallida is valuable for research, farmers, and producers of medicinal preparations.

  20. BIOCHEMICAL STUDIES ON HEPATO AND NEPHROPROTECTIVE EFFECT OF BUTTERFLY TREE (BAUHINIA PURPUREA LINN. AGAINST ACETAMINOPHEN INDUCED TOXICITY

    Directory of Open Access Journals (Sweden)

    T. Sivanagi Reddy

    2012-06-01

    Full Text Available The present study was carried out to evaluate the hepato and nephroprotective activity of ethanolic extract of stem bark of Bauhinia purpurea against paracetamol induced toxicity in rats. 100, 200 and 400 mg/kg, Oral doses of ethanolic extract of stem bark of Bauhinia purpurea was administered to group of animals for 14 days. Silymarin (25 mg/kg served as a standard and paracetamol suspension at a dose of 750 mg/kg, Body weight, was used to induce liver and kidney damage. Parameters of study were glutamate oxaloacetate transaminase (GOT, glutamate pyruvate transaminase (GPT, alkaline phosphatase (ALP, bilirubin, triglycerides and total protein as liver function tests, blood urea nitrogen (BUN, creatinine and urea as kidney function tests. Biochemical studies showed increase in the levels of serum GOT, GPT, ALP, total bilirubin, triglycerides, BUN, creatinine and urea and reduction in the levels of total protein in paracetamol induced groups. These values are retrieved significantly (p< 0.05 in a dose dependant manner by treatment with ethanolic extracts of Bauhinia purpurea stem bark at three different doses. The overall result suggests that the ethanolic extract of stem bark of Bauhinia purpurea possesses hepato and nephroprotective activity against paracetamol induced toxicity.

  1. Prey-Predator Model with Two-Stage Infection in Prey: Concerning Pest Control

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    Swapan Kumar Nandi

    2015-01-01

    Full Text Available A prey-predator model system is developed; specifically the disease is considered into the prey population. Here the prey population is taken as pest and the predators consume the selected pest. Moreover, we assume that the prey species is infected with a viral disease forming into susceptible and two-stage infected classes, and the early stage of infected prey is more vulnerable to predation by the predator. Also, it is assumed that the later stage of infected pests is not eaten by the predator. Different equilibria of the system are investigated and their stability analysis and Hopf bifurcation of the system around the interior equilibriums are discussed. A modified model has been constructed by considering some alternative source of food for the predator population and the dynamical behavior of the modified model has been investigated. We have demonstrated the analytical results by numerical analysis by taking some simulated set of parameter values.

  2. Prey size spectra and prey availability of larval and small juvenile cod

    DEFF Research Database (Denmark)

    Munk, Peter

    1997-01-01

    The aim of the present study is to describe the prey preference characteristics of cod larvae and assess preference variability in relation to species and size composition of copepod prey. A further aim is to examine the hypothesis that dietary prey size spectra remain the same during the larval...... stage when viewed on a relative predator/prey size scale. The study is based on stomach analysis of larval/juvenile cod in the size range 10-35 mm from nursery grounds in the North Sea. Stomach contents (species, size) were compared to environmental composition and preference indices were calculated....... Prey size spectra had the expected relationship to larval cod size, and preference for given copepod species could be ascribed to their relative size; Additional species-specific preferences were evident, for example the larger Pseudocalanus and the larger Calanus spp. were highly preferred. Available...

  3. An impulsive predator-prey model with disease in the prey for integrated pest management

    Science.gov (United States)

    Shi, Ruiqing; Chen, Lansun

    2010-02-01

    In this paper, an impulsive predator-prey model with disease in the prey is investigated for the purpose of integrated pest management. In the first part of the main results, we get the sufficient condition for the global stability of the susceptible pest-eradication periodic solution. This means if the release amount of infective prey and predator satisfy the condition, then the pest will be doomed. In the second part of the main results, we also get the sufficient condition for the permanence of the system. This means if the release amount of infective prey and predator satisfy the condition, then the prey and the predator will coexist. In the last section, we interpret our mathematical results. We also point out some possible future work.

  4. [Response of Picea purpurea and Abies faxoniana tree rings at different slope aspects to rapid warming in western Sichuan, China].

    Science.gov (United States)

    Guo, Bin-de; Zhang, Yuan-dong; Wang, Xiao-chun

    2016-02-01

    By using an empirical 'signal-free' standardization approach, we constructed four Picea purpurea and Abies faxoniana tree-ring chronologies at southeast and northwest slope aspects of Erdaohai and east slope aspect of Zharisi, Songpan, west Sichuan, China. The response analysis and multivariate analysis of variance between tree rings and climatic variables were conducted to explore the divergent responses of tree growth at different slope aspects to the recent warming climate. Results showed that tree growth of P. purpurea at east slope aspect was obviously accelerated (0.011 a-1) since rapid warming in 1980, whereas those at northwest slope aspect was significantly reduced (-0.006 a-1). Tree growth of P. purpurea at southeast slope aspect and A. faxoniana at northwest slope aspect decreased in significantly. With the rapid warming, growth-climate relationships of P. purpurea and A. faxoniana at different slope aspects changed significantly. After rapid warming in 1980, the promoting effects of growing season temperature (GST) on P. purpurea growth at east slope increased significantly, while the inhibitory effects of GST on its growth at southeast and northwest slopes also increased significantly. However, the effects of GST on A. faxoniana growth at northwest slope did not change significantly before and after rapid warming. The effects of precipitation in May (PM) on P. purpurea growth at east slope was changed from inhibition before rapid warming to significant promotion after rapid warming, while the inhibitory effects of PM on P. purpurea growth at southeast and northwest slopes increased significantly. For A. faioniana at northwest slope, however, it did not change obviously before and after rapid warming. The response analysis between tree growth and the Palmer drought severity index (PDSI) showed that soil moisture variations at different slope aspects were an important reason of tree-ring growth response difference since rapid warming. In addition, the

  5. KERAGAMAN GENETIK AKSESI EKINASE (Echinacea purpurea (L. Moench HASIL SELEKSI MASSA TAHUN I MELALUI ANALISIS RAPD

    Directory of Open Access Journals (Sweden)

    Dyah Subositi

    2013-07-01

    Full Text Available Ekinase (Echinacea purpurea (L. Moench a medicinal plant that has immunostimulatory activity. This plant has been cultivating in Tawangmangu region by Medicinal Plant and Traditional Medicine Research and Development Office since 2002. Ten accessions of E. purpurea were found based on their morphological variation, three accessions of them are selected as promising accessions namely BH2, BHU3 dan BHU5. The objective of this research was to observe the genetic diversity of  those  promising accessions and 8 variants accession from mass selection year I using RAPD analysis. Those accessions were amplified using 10 RAPD primers. A total of 64 scorable fragments were generated from 9 RAPD primers, among which 48 fragments (75% were polymorphic. The Dice coefficient was used to calculated the genetic similarity and UPGMA was used to generate the dendogram. The genetic similarity index among accessions evaluated ranged from 75,49-84,21% thus indicating that low level of genetic diversity. RAPD analysis proved to be efficient for genetic diversity of ekinase accessions from mass selection year I.

  6. Ameliorative potential of Tephrosia purpurea extract against arsenic induced toxicity in wistar rats

    Directory of Open Access Journals (Sweden)

    Birendra kumar Roy

    2013-05-01

    Full Text Available Aim: The present investigation has been conducted to evaluate the protective activity of Tephrosia purpurea extract (TPE against arsenic induced toxicity. Materials and Methods: For this study, twenty four wistar albino rats were taken. Control group, group – I rats were given sodium arsenite @ 10 mg/kg and group – II rats were treated with TPE @ 500 mg/kg along with sodium arsenite @ 10 mg/kg (daily oral for 28 days. On 29th day animals were slaughtered and various parameters were determined. Serum biomarkers, haematological parameter analysis and histomorphological examination are carried out with estimation of arsenic concentration in tissues. Results: Oral administration of sodium arsenite @ 10 mg/kg for 28 days resulted in a significant decrease in Hb%, TEC and TLC, significant increase of serum glucose, cholesterol, calcium and significant increase in arsenic accumulation in tissues. Histopathological results of intestine revealed haemorrhagic enteritis along with loss of villi. Treatment with Tephrosia purpurea @ 500 mg/kg significantly decreased the elevated glucose, LDH levels, along with significant increase haematological levels towards normal. There was reduced haemorrhagic enteritis and presence of intact villi, as compared to arsenic treated group. But there was no significant difference in serum calcium, serum cholesterol and arsenic concentration in tissues, when compared with arsenic treated group. Conclusion: The study conclude that supplementation of TPE (500 mg/kg daily oral for 28 days has shown protection against arsenic induced toxicity by its protective effect. [Vet World 2013; 6(8.000: 493-496

  7. Gibberellic acid increases secondary metabolite production in Echinacea purpurea hairy roots.

    Science.gov (United States)

    Abbasi, Bilal H; Stiles, Amanda R; Saxena, Praveen K; Liu, Chun-Zhao

    2012-12-01

    Gibberellic acid (GA(3)) is reported to have diverse effects on hairy root cultures of many plant species; therefore, the effects of GA(3) on the growth, secondary metabolite production (caffeic acid derivatives and lignin), phenylalanine ammonia lyase (PAL) activity, and free radical scavenging activity of light-grown Echinacea purpurea L. hairy roots were investigated. Eight concentrations of GA(3), ranging from 0.005 to 1.0 μM, were added to shake flask cultures. The moderate GA(3) concentration, 0.025 μM, resulted in the highest concentrations of cichoric acid, caftaric acid, and chlorogenic acid, as well as increased PAL activity, cell viability, and free radical scavenging activity, while higher and lower GA(3) concentrations resulted in reduced levels compared to the control (lacking GA(3)). The moderate GA(3) concentration also affected root morphogenesis; supplementation with 0.025 μM GA(3) resulted in the development of thick, dense, purple-colored roots, while roots exposed to the higher and lower concentrations of GA(3) were thin and off-white. This study demonstrates that supplementation with GA(3) may be an excellent strategy to optimize the production of secondary metabolites from E. purpurea hairy root cultures; however, the GA(3) concentration is a critical factor.

  8. Echinacea purpurea supplementation does not enhance VO2max in distance runners.

    Science.gov (United States)

    Baumann, Cory W; Bond, Kelsey L; Rupp, Jeffrey C; Ingalls, Christopher P; Doyle, J Andrew

    2014-05-01

    Oral supplementation of Echinacea purpurea (ECH) has been reported to increase levels of serum erythropoietin and as a result improve endurance performance in untrained subjects. The purpose of this study was to determine if ECH supplementation alters maximal oxygen uptake (VO2max) in trained endurance runners. Using a double-blind design, 16 trained endurance runners (9 ECH and 7 placebo [PLA]) supplemented with either 8,000 mg·d(-1) of ECH or wheat flour (PLA) for 6 weeks. Maximal aerobic treadmill tests and blood samples were measured before and after supplementation to determine VO2max, hematocrit (Hct), and hemoglobin (Hb). VO2max, Hct, and Hb did not differ between the ECH and PLA groups before or after supplementation. Furthermore, supplementation of ECH failed to improve VO2max (67.37 ± 4.62 vs. 67.23 ± 5.82 ml·kg(-1)·min(-1)), Hct (43.57 ± 2.38 vs. 42.85 ± 1.46%), or Hb (14.93 ± 1.27 vs. 15.55 ± 0.80 g·dL(-1)) from baseline measurements. Echinacea purpurea supplementation of 8,000 mg·d(-1) for 6 weeks failed to increase VO2max, Hct, or Hb in trained endurance runners and thus does not seem to influence physiological variables that affect distance running performance.

  9. Echinacea purpurea root extract enhances the adipocyte differentiation of 3T3-L1 cells.

    Science.gov (United States)

    Shin, Dong-Mi; Choi, Kyeong-Mi; Lee, Youn-Sun; Kim, Wonkyun; Shin, Kyong-Oh; Oh, Seikwan; Jung, Jae-Chul; Lee, Mi Kyeong; Lee, Yong-Moon; Hong, Jin Tae; Yun, Yeo-Pyo; Yoo, Hwan-Soo

    2014-06-01

    Echinacea purpurea has been shown to have anti-diabetic activities; for example, it activates peroxisome proliferator-activated receptor γ (PPARγ) and increases insulin-stimulated glucose uptake. Adipogenesis has been used to study the insulin signaling pathway and to screen anti-diabetic compounds. The present study was conducted to investigate the effects of an ethanol extract of E. purpurea (EEEP) and its constituents on the insulin-induced adipocyte differentiation of 3T3-L1 preadipocytes. When adipocyte differentiation was induced with insulin plus 3-isobutyl-1-methylxanthine and dexamethasone, the accumulation of lipid droplets and the cellular triglyceride content were significantly increased by EEEP. The expressions of PPARγ and C/EBPα in adipocytes treated with EEEP were gradually increased as compared with control cells. Fat accumulation and triglyceride content of adipocytes treated with dodeca-2(E),4(E)-dienoic acid isobutylamide were significantly increased as compared with control cells. The expressions of PPARγ and C/EBPα in adipocytes treated with dodeca-2(E),4(E)-dienoic acid isobutylamide were significantly higher than in control cells. These results suggest EEEP promotes the adipogenesis that is partially induced by insulin and that dodeca-2(E),4(E)-dienoic acid isobutylamide appears to be responsible for EEEP-enhanced adipocyte differentiation.

  10. Antibodies against Yariv's reagent for immunolocalization of arabinogalactan-proteins in aerial parts of Echinacea purpurea.

    Science.gov (United States)

    Göllner, Esther Marie; Gramann, Jean Christian; Classen, Birgit

    2013-01-01

    Arabinogalactan-proteins are glycoproteins that occur in higher plants and are involved in important processes like cell differentiation and plant growth. In the medicinal plant Echinacea purpurea L., they belong to the putative immunomodulating compounds and are structurally well characterized. For microscopic localization of arabinogalactan-proteins, synthetic (β-D-Glc)3 Yariv phenylglycoside that specifically binds to most plant arabinogalactan-proteins was used to label arabinogalactan-proteins in fresh cut sections of stems and petioles of Echinacea purpurea. Polyclonal antibodies against (β-D-Glc)3 Yariv phenylglycoside were used to detect the arabinogalactan-protein-(β-D-Glc)3 Yariv phenylglycoside complex. After addition of fluorescein isothiocyanate-conjugated secondary antibodies, the sections were analyzed by confocal laser scanning microscopy. Arabinogalactan-proteins are localized mainly in the central cylinder in the collateral vascular bundles, especially in the area of the xylem. In cell walls of fully differentiated vessels and tracheids, arabinogalactan-proteins have been detected mainly at the inner area of the wall close to the cell lumina. Intense labeling occurs around pit canals connecting adjacent vessels. Furthermore, arabinogalactan-proteins are present in the lumina of cells of the sclerenchyma caps and in companion cells of the phloem. Georg Thieme Verlag KG Stuttgart · New York.

  11. Characterization and immunolocalization of arabinogalactan-proteins in roots of Echinacea purpurea.

    Science.gov (United States)

    Bossy, Andreas; Blaschek, Wolfgang; Classen, Birgit

    2009-11-01

    From the high molecular weight fraction of an aqueous extract from roots of Echinacea purpurea L. Moench, arabinogalactan-proteins (AGPs), a class of proteoglycans proposed to be involved in cell differentiation and plant growth, were purified and characterized with regard to amino acid composition and structure of the polysaccharide moiety. The protein content of the AGP was 5.0 % (w/w) with the dominating amino acids Glx, Hyp, Asx, Ser, Thr and Ala. The highly branched polysaccharide moiety shows a linkage composition typical of AGPs with 1,3-, 1,6- and 1,3,6-linked galactopyranosyl residues and arabinofuranosyl residues predominantly as terminal and 1,5-linked residues. Terminal units of glucuronopyranose acid were also detected. Furthermore, a new method for the localization of AGPs in plant tissue has been developed. The synthetic (beta- D-Glc)(3) Yariv phenylgycoside (betaGlcY) is known to specifically bind to AGPs. For immunolocalization, polyclonal betaGlcY-antibodies have been generated and were used to label Yariv-treated thin sections of roots from E. purpurea. After addition of the FITC-conjugated secondary antibody, the sections were analyzed by confocal laser scanning microscopy. AGPs are detected mainly in the central cylinder in the area of the xylem. Cell walls of vessels and tracheids are strongly labelled, especially at the inner area of the wall. Furthermore, there is intense labelling of the pit canals. Georg Thieme Verlag KG Stuttgart, New York.

  12. Production of cadiotonic glycosides in Digitalis purpurea using temporary immersion systems

    Directory of Open Access Journals (Sweden)

    Naivy Pérez-Alonso

    2005-01-01

    Full Text Available Digitalis purpurea, is an example of cardiotonic drug. Digoxin and digitoxin are glycosides produced by this plant which are cardiac stimulants with a wide use in the treatment of heart problems. The objective of this investigation was to study the effect of temporary immersion on biomass production and the content of cardiotonic glycosides (digitoxin and digoxin, determined by Liquid Cromatography. Biomass production was favoured by increasing the frequency of immersions. The highest value of fresh weight (106.2 g and lower porcentage of hyperhydricity (27 % were obtained with immersions of 2 minutes every 4 hours. The content of digoxin was always lower than digitoxin. However, the concentration of digoxin increases with 6 and 8 immersions per day, while the accumulation of digitoxin was stable in all treatments. The aeration rates did not increase the biomasss and the concentration of digoxine was nule, nevertheless the concentration of digitoxine increased up to 111μg g.DW. The effect of temporary immersion on glycosides accumulation in shoots of Digitalis purpurea presented in this paper has not been described in the literature till now. temporary immersion Keywords: digitoxin, digoxin, secondary metabolites,

  13. Comparison of alkylamide yield in ethanolic extracts prepared from fresh versus dry Echinacea purpurea utilizing HPLC-ESI-MS.

    Science.gov (United States)

    Spelman, Kevin; Wetschler, Matthew H; Cech, Nadja B

    2009-07-12

    Echinacea purpurea (L.) Moench, a top selling botanical medicine, is currently of considerable interest due to immunomodulatory, anti-inflammatory, antiviral and cannabinoid receptor 2 (CB2) binding activities of its alkylamide constituents. The purpose of these studies was to comprehensively profile the alkylamide (alkamide) content of E. purpurea root, and to compare yields of alkylamide constituents resulting from various ethanolic extraction procedures commonly employed by the dietary supplements industry. To accomplish this goal, a high performance liquid chromatography-electrospray ionization mass spectrometry (HPLC-ESI-MS) method was validated for quantitative analysis of several E. purpurea alkylamides. Using this method, at least 15 alkylamides were identified and it was shown that fresh and dry E. purpurea extracts prepared from equivalent amounts (dry weight) of roots, with exceptions, exhibited similar yield of specific alkylamides. However, the amount of total dissolved solids in the dry extract was higher (by 38%) than the fresh extract. Two extracts prepared from dried roots at different ratios of root:solvent (1:5, w:v and 1:11, w:v) were similar in yield of total dissolved solids, but, there were differences in quantities of specific alkylamides extracted using these two root:solvent ratios. In addition, the important bioactive dodecatetraenoic acid isobutylamides are fully extracted from dry E. purpurea root in 2 days, suggesting that the manufacturing practice of macerating Echinacea extracts for weeks may be unnecessary for optimal alkylamide extraction. Finally, the identification of a new alkylamide has been proposed. These results demonstrate the differences of the described extractions and utility of the analytical methods used to determine the wide-ranging individual alkylamide content of commonly consumed Echinacea extracts.

  14. A non-autonomous stochastic predator-prey model.

    Science.gov (United States)

    Buonocore, Aniello; Caputo, Luigia; Pirozzi, Enrica; Nobile, Amelia G

    2014-04-01

    The aim of this paper is to consider a non-autonomous predator-prey-like system, with a Gompertz growth law for the prey. By introducing random variations in both prey birth and predator death rates, a stochastic model for the predator-prey-like system in a random environment is proposed and investigated. The corresponding Fokker-Planck equation is solved to obtain the joint probability density for the prey and predator populations and the marginal probability densities. The asymptotic behavior of the predator-prey stochastic model is also analyzed.

  15. In vitro CYP3A4 metabolism: inhibition by Echinacea purpurea and choice of substrate for the evaluation of herbal inhibition.

    Science.gov (United States)

    Hansen, Torstein Schrøder; Nilsen, Odd Georg

    2008-11-01

    The in vitro CYP3A4 inhibition profiles of Echinacea purpurea, St. John's wort and ketoconazole were evaluated by three different substrates: 7-benzyloxy-trifluoromethylcoumarin (BFC), 7-benzyloxyquinoline (BQ) and testosterone. St. John's wort and ketoconazole produced similar inhibition profiles regardless of substrate. For E. purpurea, testosterone metabolism showed a much lower CYP3A4 inhibition (IC(50) 5394 microg/ml) compared to the fluorescent substrates BFC and BQ (IC(50) 354 and 452 mg/ml, respectively). It is suggested that the substrate/assay-dependent effects may arise from a complex nature of E. purpurea constituents, involving different CYP3A4 substrate binding sites. The choice of substrate might thus be essential for evaluation of the inhibition of CYP3A4 metabolism for some herbs. A weak inhibition potential of E. purpurea towards CYP3A4-mediated metabolism in vitro was confirmed by the use of three different substrates.

  16. Wild North Island Robins (Petroica longipes respond to Prey Animacy

    Directory of Open Access Journals (Sweden)

    Alexis Garland

    2014-08-01

    Full Text Available North Island robins of New Zealand are a food hoarding species, which is unique in that they almost exclusively cache highly perishable hunted insects for later retrieval. In order to do so, they either kill and dismember or paralyze their prey for caching, depending on the prey size and kind. The present study comprises two experiments, using a Violation of Expectancy (VoE paradigm to examine variation in search behavior response to different prey conditions. The first experiment presents three different types of prey (mealworms, earthworms and locusts in expected (present and unexpected (absent conditions. The second experiment presents prey in varying states of animacy (alive and whole, dead and whole, dead and halved, and an inanimate stick and reveals prey in expected (same state or unexpected (differing state conditions. While robins did not respond with differential search times to different types of unexpectedly missing prey in Experiment 1, in Experiment 2 robins searched longer in conditions where prey was found in a differing state of animacy than initially shown. Robins also searched longer for prey when immediately consuming retrieved prey than when caching retrieved prey. Results indicate that North Island robins may be sensitive to prey animacy upon storage and retrieval of insect prey; such information could play a role in storage, pilfering and retrieval strategies of such a perishable food source.

  17. Predator-prey encounters in turbulent waters

    DEFF Research Database (Denmark)

    Mann, J.; Ott, Søren; Pécseli, H.L.;

    2002-01-01

    With reference to studies of predator-prey encounters in turbulent waters, we demonstrate the feasibility of an experimental method for investigations of particle fluxes to an absorbing surface in turbulent flows. A laboratory experiment is carried out, where an approximately homogeneous and isot......With reference to studies of predator-prey encounters in turbulent waters, we demonstrate the feasibility of an experimental method for investigations of particle fluxes to an absorbing surface in turbulent flows. A laboratory experiment is carried out, where an approximately homogeneous...

  18. GIS-based characterization of the geographic distributions of wild and cultivated populations of the Mesoamerican fruit tree Spondias purpurea (Anacardiaceae).

    Science.gov (United States)

    Miller, Allison J; Knouft, Jason H

    2006-12-01

    Humans are having a profound impact on the geographic distributions of plant populations. In crop species, domestication has been accompanied by the geographic expansion of cultivated populations relative to their wild ancestors. We used a geographical information system (GIS)-based approach to investigate differences in the environmental factors characterizing the geographic distributions of cultivated and wild populations of the Mesoamerican fruit tree Spondias purpurea. Locality data for 86 cultivated and 28 wild S. purpurea populations were used in conjunction with environmental data layers and Maxent, a maximum entropy application for predicting species distributions. Interpredictivity analyses and principal components analysis revealed that the predicted distribution of wild S. purpurea is nested within the cultivated distribution and that the ecological niche (defined by environmental characteristics) of cultivated S. purpurea has expanded relative to that of wild populations. Significant differences between wild and cultivated populations were detected for five environmental variables, corresponding to the expansion of S. purpurea during the domestication process from its native habitat in the Mesoamerican tropical dry forests into less seasonal habitats. These data suggest that humans have altered the range of habitats occupied by cultivated S. purpurea populations relative to their wild progenitors.

  19. Human activity helps prey win the predator-prey space race.

    Science.gov (United States)

    Muhly, Tyler B; Semeniuk, Christina; Massolo, Alessandro; Hickman, Laura; Musiani, Marco

    2011-03-02

    Predator-prey interactions, including between large mammalian wildlife species, can be represented as a "space race", where prey try to minimize and predators maximize spatial overlap. Human activity can also influence the distribution of wildlife species. In particular, high-human disturbance can displace large carnivore predators, a trait-mediated direct effect. Predator displacement by humans could then indirectly benefit prey species by reducing predation risk, a trait-mediated indirect effect of humans that spatially decouples predators from prey. The purpose of this research was to test the hypothesis that high-human activity was displacing predators and thus indirectly creating spatial refuge for prey species, helping prey win the "space race". We measured the occurrence of eleven large mammal species (including humans and cattle) at 43 camera traps deployed on roads and trails in southwest Alberta, Canada. We tested species co-occurrence at camera sites using hierarchical cluster and nonmetric multidimensional scaling (NMS) analyses; and tested whether human activity, food and/or habitat influenced predator and prey species counts at camera sites using regression tree analysis. Cluster and NMS analysis indicated that at camera sites humans co-occurred with prey species more than predator species and predator species had relatively low co-occurrence with prey species. Regression tree analysis indicated that prey species were three times more abundant on roads and trails with >32 humans/day. However, predators were less abundant on roads and trails that exceeded 18 humans/day. Our results support the hypothesis that high-human activity displaced predators but not prey species, creating spatial refuge from predation. High-human activity on roads and trails (i.e., >18 humans/day) has the potential to interfere with predator-prey interactions via trait-mediated direct and indirect effects. We urge scientist and managers to carefully consider and quantify the

  20. Feeding, prey selection and prey encounter mechanisms in the heterotrophic dinoflagellate Noctiluca scintillans

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; Titelman, J.

    1998-01-01

    by modeling N.scintillans both as a spherical and as a cylindrical collector. The latter model assumes that prey particles are collected on the string of mucus that may form at the tip of the tentacle. Feeding, growth and prey selection experiments all demonstrated that diatoms are cleared at substantially...... and that the high ascent velocity accounts for encounters with prey. However, the flow field around the cell-mucus complex is too complicated to be described accurately by simple geometric models. Fluid shear (0.7-1.8 s(-1)) had a negative impact on feeding rates, which were much less than predicted by models...

  1. Stability and Hopf bifurcation in a diffusive predator-prey system incorporating a prey refuge.

    Science.gov (United States)

    Chang, Xiaoyuan; Wei, Junjie

    2013-08-01

    A diffusive predator-prey model with Holling type II functional response and the no-flux boundary condition incorporating a constant prey refuge is considered. Globally asymptotically stability of the positive equilibrium is obtained. Regarding the constant number of prey refuge m as a bifurcation parameter, by analyzing the distribution of the eigenvalues, the existence of Hopf bifurcation is given. Employing the center manifold theory and normal form method, an algorithm for determining the properties of the Hopf bifurcation is derived. Some numerical simulations for illustrating the analysis results are carried out.

  2. Human activity helps prey win the predator-prey space race.

    Directory of Open Access Journals (Sweden)

    Tyler B Muhly

    Full Text Available Predator-prey interactions, including between large mammalian wildlife species, can be represented as a "space race", where prey try to minimize and predators maximize spatial overlap. Human activity can also influence the distribution of wildlife species. In particular, high-human disturbance can displace large carnivore predators, a trait-mediated direct effect. Predator displacement by humans could then indirectly benefit prey species by reducing predation risk, a trait-mediated indirect effect of humans that spatially decouples predators from prey. The purpose of this research was to test the hypothesis that high-human activity was displacing predators and thus indirectly creating spatial refuge for prey species, helping prey win the "space race". We measured the occurrence of eleven large mammal species (including humans and cattle at 43 camera traps deployed on roads and trails in southwest Alberta, Canada. We tested species co-occurrence at camera sites using hierarchical cluster and nonmetric multidimensional scaling (NMS analyses; and tested whether human activity, food and/or habitat influenced predator and prey species counts at camera sites using regression tree analysis. Cluster and NMS analysis indicated that at camera sites humans co-occurred with prey species more than predator species and predator species had relatively low co-occurrence with prey species. Regression tree analysis indicated that prey species were three times more abundant on roads and trails with >32 humans/day. However, predators were less abundant on roads and trails that exceeded 18 humans/day. Our results support the hypothesis that high-human activity displaced predators but not prey species, creating spatial refuge from predation. High-human activity on roads and trails (i.e., >18 humans/day has the potential to interfere with predator-prey interactions via trait-mediated direct and indirect effects. We urge scientist and managers to carefully consider and

  3. Optimum prey capture techniques in fish

    NARCIS (Netherlands)

    Leeuwen, van J.L.

    1983-01-01

    In this thesis hydrodynamic principles are used to quantify relations between form and function in the prey capture mechanism of actinopterygian fish. This work is closely related to the papers on the hydrodynamics of fish feeding by Muller et al. (1982) and Muller & Osse (in press).

  4. Predators, prey, and natural disasters attract ecologists.

    Science.gov (United States)

    Mlot, C

    1993-08-27

    Some 2200 ecologists turned out for the 78th annual meeting of the Ecological Society of America (ESA), held in Madison, Wisconsin, 31 July to 4 August. Among the offerings: reports on the effect of dams and levees on large river ecology, predator-prey interactions, how parasites might control evolution, and the impact of clearcutting on soil organisms.

  5. Motor control: how dragonflies catch their prey.

    Science.gov (United States)

    Dickinson, Michael H

    2015-03-16

    Detailed measurements of head and body motion have revealed previously unknown complexity in the predatory behavior of dragonflies. The new evidence suggests that the brains of these agile predators compute internal models of their own actions and those of their prey.

  6. SRKW summer prey - Prey species and stock specific consumption estimates for SRKW in their summer range

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Southern Resident Killer Whales (SRKW) are listed as a Distinct Population Segment under the Endangered Species Act. Data concerning their prey species and stock...

  7. Killer whale prey - Determining prey selection by southern resident killer whales (SRKW)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Prey selectivity by southern resident killer whales is being determined by analyses of fish scales and tissue from predation events and feces. Information on killer...

  8. Prey perception in feeding-current feeding copepods

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; Goncalves, Rodrigo J.; Florian Couespel, Damien

    2016-01-01

    We reply to the comments of Paffenhöfer and Jiang () who argues that remote chemical prey perception is necessary for feeding-current feeding copepods to fulfill their nutritional requirements in a dilute ocean, that remote chemical prey detection may only be observed at very low prey concentrati...

  9. Coexistence Steady States in a Predator-Prey Model

    CERN Document Server

    Walker, Christoph

    2010-01-01

    An age-structured predator-prey system with diffusion and Holling-Tanner-type nonlinearities is considered. Regarding the intensity of the fertility of the predator as bifurcation parameter, we prove that a branch of positive coexistence steady states bifurcates from the marginal steady state with no prey. A similar result is obtained when the fertility of the prey varies.

  10. Harvesting and Conversation in a Predator-Prey System

    NARCIS (Netherlands)

    Hoekstra, Jeljer; Bergh, van den Jeroen C.J.M.

    2001-01-01

    Optimal harvesting of prey in a predator-prey ecosystem is studiedunder the condition that the existence of the predator has value. Predators (birds) and humans (fishers) compete for prey (shellfish). The behavior of the system is studied and conditions for optimal control are deduced. Various optim

  11. The functional response to prey density in an acarine system

    NARCIS (Netherlands)

    Fransz, H.G.

    1974-01-01

    Predacious mites are considered to be important natural enemies of phytophagous mites. Their efficiency in the natural control of prey populations depends on the relationships of the number of prey killed per predator per time unit and the oviposition rate on the one hand and prey density on the

  12. Analysis of a Periodic Impulsive Predator-Prey System with Disease in the Prey

    Directory of Open Access Journals (Sweden)

    Lianwen Wang

    2013-01-01

    Full Text Available We investigate a periodic predator-prey system subject to impulsive perturbations, in which a disease can be transmitted among the prey species only, in this paper. With the help of the theory of impulsive differential equations and Lyapunov functional method, sufficient conditions for the permanence, global attractivity, and partial extinction of system are established, respectively. It is shown that impulsive perturbations contribute to the above dynamics of the system. Numerical simulations are presented to substantiate the analytical results.

  13. The influence of intraguild predation on prey suppression and prey release: a meta-analysis.

    Science.gov (United States)

    Vance-Chalcraft, Heather D; Rosenheim, Jay A; Vonesh, James R; Osenberg, Craig W; Sih, Andrew

    2007-11-01

    Intraguild predation (IGP) occurs when one predator species consumes another predator species with whom it also competes for shared prey. One question of interest to ecologists is whether multiple predator species suppress prey populations more than a single predator species, and whether this result varies with the presence of IGP. We conducted a meta-analysis to examine this question, and others, regarding the effects of IGP on prey suppression. When predators can potentially consume one another (mutual IGP), prey suppression is greater in the presence of one predator species than in the presence of multiple predator species; however, this result was not found for assemblages with unidirectional or no IGP. With unidirectional IGP, intermediate predators were generally more effective than the top predator at suppressing the shared prey, in agreement with IGP theory. Adding a top predator to an assemblage generally caused prey to be released from predation, while adding an intermediate predator caused prey populations to be suppressed. However, the effects of adding a top or intermediate predator depended on the effectiveness of these predators when they were alone. Effects of IGP varied across different ecosystems (e.g., lentic, lotic, marine, terrestrial invertebrate, and terrestrial vertebrate), with the strongest patterns being driven by terrestrial invertebrates. Finally, although IGP theory is based on equilibrium conditions, data from short-term experiments can inform us about systems that are dominated by transient dynamics. Moreover, short-term experiments may be connected in some way to equilibrium models if the predator and prey densities used in experiments approximate the equilibrium densities in nature.

  14. Applications of the Phytomedicine Echinacea purpurea (Purple Coneflower in Infectious Diseases

    Directory of Open Access Journals (Sweden)

    James B. Hudson

    2012-01-01

    Full Text Available Extracts of Echinacea purpurea (EP, purple coneflower have been used traditionally in North America for the treatment of various types of infections and wounds, and they have become very popular herbal medicines globally. Recent studies have revealed that certain standardized preparations contain potent and selective antiviral and antimicrobial activities. In addition, they display multiple immune-modulatory activities, comprising stimulation of certain immune functions such as phagocytic activity of macrophages and suppression of the proinflammatory responses of epithelial cells to viruses and bacteria, which are manifested as alterations in secretion of various cytokines and chemokines. These immune modulations result from upregulation or downregulation of the relevant genes and their transcription factors. All these bioactivities can be demonstrated at noncytotoxic concentrations of extract and appear to be due to multiple components rather than the individual chemical compounds that characterize Echinacea extracts. Potential applications of the bioactive extracts may go beyond their traditional uses.

  15. Applications of the phytomedicine Echinacea purpurea (Purple Coneflower) in infectious diseases.

    Science.gov (United States)

    Hudson, James B

    2012-01-01

    Extracts of Echinacea purpurea (EP, purple coneflower) have been used traditionally in North America for the treatment of various types of infections and wounds, and they have become very popular herbal medicines globally. Recent studies have revealed that certain standardized preparations contain potent and selective antiviral and antimicrobial activities. In addition, they display multiple immune-modulatory activities, comprising stimulation of certain immune functions such as phagocytic activity of macrophages and suppression of the proinflammatory responses of epithelial cells to viruses and bacteria, which are manifested as alterations in secretion of various cytokines and chemokines. These immune modulations result from upregulation or downregulation of the relevant genes and their transcription factors. All these bioactivities can be demonstrated at noncytotoxic concentrations of extract and appear to be due to multiple components rather than the individual chemical compounds that characterize Echinacea extracts. Potential applications of the bioactive extracts may go beyond their traditional uses.

  16. Endophytic and rhizospheric bacterial communities isolated from the medicinal plants Echinacea purpurea and Echinacea angustifolia.

    Science.gov (United States)

    Chiellini, Carolina; Maida, Isabel; Emiliani, Giovanni; Mengoni, Alessio; Mocali, Stefano; Fabiani, Arturo; Biffi, Sauro; Maggini, Valentina; Gori, Luigi; Vannacci, Alfredo; Gallo, Eugenia; Firenzuoli, Fabio; Fani, Renato

    2014-09-01

    In this work we analyzed the composition and structure of cultivable bacterial communities isolated from the stem/leaf and root compartments of two medicinal plants, Echinacea purpurea (L.) Moench and Echinacea angustifolia (DC.) Hell, grown in the same soil, as well as the bacterial community from their rhizospheric soils. Molecular PCR-based techniques were applied to cultivable bacteria isolated from the three compartments of the two plants. The results showed that the two plants and their respective compartments were characterized by different communities, indicating a low degree of strain sharing and a strong selective pressure within plant tissues. Pseudomonas was the most highly represented genus, together with Actinobacteria and Bacillus spp. The presence of distinct bacterial communities in different plant species and among compartments of the same plant species could account for the differences in the medicinal properties of the two plants. Copyright© by the Spanish Society for Microbiology and Institute for Catalan Studies.

  17. Studies on the Insecticidal and Repellent Properties of the Seed Extract of Tephrosia Purpurea (LINN Pers

    Directory of Open Access Journals (Sweden)

    B. N. Saxena

    1974-04-01

    Full Text Available Laboratory and field trials were conducted to find out the insecticidal and repellent properties of petroleum ether extract of the seeds of Tephrosia purpurea. In laboratory trials contact toxicity of the extract was assessed against land leeches, houseflies, mosquitoes, rice weevil and flour beetle. In field trials, the repellency of the extract was assessed against land leeches, mosquitoes and simulium flies. In laboratory trials, the dosage required for 100 per cent mortality was 0.0005 gm/cm/sup 2/ for land leeches, 0.0157 gm/cm/sup 2/ for flour beetle. In field trials, the extract was found to be repellent against land leeches for 5 hours, mosquitoes for 4 hours and simulium flies for 5 hours.

  18. Spasmolytic activity of a herbal drug isolated from Tephrosia purpurea in guinea pigs.

    Science.gov (United States)

    Soni, Kapil K; Khare, M L; Saxena, R C

    2004-04-01

    We investigated the spasmolytic activity of herbal drugs isolated from Tephrosia purpurea on guinea pigs for the treatment of asthma in India. For this investigation, the herbal drug was extracted with 70% ethanol in soxhlet apparatus. After purification and isolution, the drug was used in experimental animals to observe prophylactic activity. For anaphylactic activity, horse serum 0.5 ml along with triple antigen (0.5 ml) was induced in guinea pigs. To observe prophylactic activity, male guinea pigs weighing about 250-450 gms were killed by cervical dislocation and the trachea was isolated. Each trachea was cut in to six segments. Each segment consists of three cartilage rings. Each end of tracheal muscles was attached to the bronchospasm transducers for isometric recording of the tension charges on a polygraph. The results of experiments clearly showed the spasmolytic activity of the drug. The preliminary phytochemical investigation, however shows the presence of glycoside saponins.

  19. Antihyperglycemic and antihyperlipidemic effects of Tephrosia purpurea leaf extract in streptozotocin induced diabetic rats.

    Science.gov (United States)

    Pavana, P; Manoharan, S; Renju, G L; Sethupathy, S

    2007-10-01

    Diabetes mellitus is a worldwide leading metabolic syndrome, associated with profound alterations in carbohydrate, lipids, lipoproteins and protein metabolisms. Worldwide, traditional practitioners for the treatment of diabetes and its complications use a wide variety of medicinal plants. In the present study the aqueous extract of Tephrosia purpurea leaves (TpALet) was evaluated for its antihyperglycemic and antihyperlipidemic effects in streptozotocin induced diabetic rats. Profound alterations in the concentrations of blood glucose, lipids and lipoproteins were observed in diabetic rats. Oral administration of TpALet to diabetic rats at a dose of 600 mg/kg body weight significantly reduced the level of blood glucose and increased the level of plasma insulin as well as normalized the lipids and lipoproteins profile. The present study thus demonstrated that TpALet has prominent antihyperglycemic and antihyperlipidemic effects in streptozotocin induced diabetic rats.

  20. Phylogenetic Diversity and Antifungal Activity of Endophytic Fungi Associated with Tephrosia purpurea.

    Science.gov (United States)

    Luo, Ze-Ping; Lin, Hai-Yan; Ding, Wen-Bing; He, Hua-Liang; Li, You-Zhi

    2015-12-01

    Sixty-one endophytic fungus strains with different colony morphologies were isolated from the leaves, stems and roots of Tephrosia purpurea with colonization rates of 66.95%, 37.50%, and 26.92%, respectively. Based on internal transcribed spacer sequence analysis, 61 isolates were classified into 16 genera belonging to 3 classes under the phylum Ascomycota. Of the 61 isolates, 6 (9.84%) exhibited antifungal activity against one or more indicator plant pathogenic fungi according to the dual culture test. Isolate TPL25 had the broadest antifungal spectrum of activity, and isolate TPL35 was active against 5 plant pathogenic fungi. Furthermore, culture filtrates of TPL25 and TPL35 exhibited greater than 80% growth inhibition against Sclerotinia sclerotiorum. We conclude that the endophytic fungal strains TPL25 and TPL35 are promising sources of bioactive compounds.

  1. Characters with multiple usages- phenotypic variability analysis at Echinacea purpurea (L. Moench species

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    Mihai Radu POP

    2010-11-01

    Full Text Available Merging aesthetics with utility, some medicinal plants can benefit both of a high production and decoration potential. This calls for diversification of improvement directions of the species. Through this article we suggest one of these species, Echinacea purpurea (L. Moench. This is considered to be important at this time, acquisition of new biological forms - varieties in this species, which show multiple attributes utility based on key biological characteristics, agronomic, physiological, biochemical and agrochemical (medicinal, decorative, culinary etc.. To achieve this goal, studies were undertaken, given in this article, which is the starting point for selecting characters representative for our targets.The results presented in this study reveal a pronounced genetic polymorphism showing the selection operation can use the original material for a quantitative and qualitative differentiation of valuable genotypes that could be approved.

  2. Сравнительный фитохимический анализ цветков rudbeckia hirta l. и echinacea purpurea l.

    OpenAIRE

    Лукашов, Р. И.; Д. В. Моисеев

    2012-01-01

    The botanical characteristic of Echinacea purpurea L. as the inserted species form the Republic of Belarus is given. Identification of raw Echinacea purpurea L. harvested in the territory of the Republic of Belarus is held. The alcohols extracts of Echinacea purpurea L. contained a significant amount of hydroxycinnamic acids and a few amount flavonoids. The flavonoid composition of Rudbeckia hirta L. compared with the composition of Echinacea purpurea L. flavonoids is more var...

  3. Alterations in prey capture and induction of metallothioneins in grass shrimp fed cadmium-contaminated prey

    Energy Technology Data Exchange (ETDEWEB)

    Wallace, W.G.; Hoexum Brouwer, T.M.; Brouwer, M.; Lopez, G.R.

    2000-04-01

    The aquatic oligochaete Limnodrilus hoffmeisteri from a Cd-contaminated cove on the Hudson River, Foundry Cove, New York, USA, has evolved Cd resistance. Past studies have focused on how the mode of detoxification of Cd by these Cd-resistant worms influences Cd trophic transfer to the grass shrimp Palaemonetes pugio. In the present study, the authors investigate reductions in prey capture in grass shrimp fed Cd-contaminated prey. They also investigate the induction of metal-binding proteins, metallothioneins, in these Cd-exposed shrimp. Grass shrimp were fed field-exposed Cd-contaminated Foundry Cove oligochaetes or laboratory-exposed Cd-contaminated Artemia salina. Following these exposures, the ability of Cd- dosed and control shrimp to capture live A. salina was compared. Results show that shrimp fed laboratory-exposed Cd-contaminated A. salina for 2 weeks exhibit significant reductions in their ability to successfully capture prey (live A. salina). Reductions in prey capture were also apparent, though not as dramatic in shrimp fed for 1 week on field-exposed Cd-contained Foundry Cove oligochaetes. Shrimp were further investigated for their subcellular distribution of Cd to examine if alterations in prey capture could be linked to saturation of Cd-metallothionein. Cd-dosed shrimp produced a low molecular weight CD-binding metallothionein protein in a dose- and time-dependent manner. Most importantly, successful prey capture decreased with increased Cd body burdens and increased Cd concentration bound to high molecular weight proteins.

  4. Prey carriage varies with prey size in Cerceris fumipennis (Hymenoptera, Crabronidae

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    Christine Nalepa

    2015-06-01

    Full Text Available Exploitation of the hunting behavior of the solitary wasp Cerceris fumipennis is proving to be a useful method for detecting pest Buprestidae as well as for documenting buprestid diversity in eastern North America. Here we review prey carriage mechanisms in the species, and conclude that variation in prey carriage is correlated with the spectacular size range of their buprestid prey (4.9–22.3 mm length. Small prey items, including Agrilus species, are transported with the aid of a specialized morphological structure on the fifth metasomal sternite (“buprestid clamp”, resulting in a distinct curved posture during flight. Analysis of prey items from C. fumipennis in North Carolina in 2014 indicates that 30% of collected Agrilus spp. were not paralyzed prior to wasp arrival at the nest, and suggests that the buprestid clamp may function to prevent the escape of active small prey. Recognition that the curved flight posture of a female approaching her nest is a signal that she may be carrying a beetle in the genus Agrilus can improve efficiency of biosurveillance for pest Buprestidae.

  5. Echinacea purpurea and osteopathic manipulative treatment in children with recurrent otitis media: a randomized controlled trial.

    Science.gov (United States)

    Wahl, Richard A; Aldous, Michael B; Worden, Katherine A; Grant, Kathryn L

    2008-10-02

    Recurrent otitis media is a common problem in young children. Echinacea and osteopathic manipulative treatment have been proposed as preventive measures, but have been inadequately studied. This study was designed to assess the efficacy of Echinacea purpurea and/or osteopathic manipulative treatment (OMT) for prevention of acute otitis media in otitis-prone children. A randomized, placebo-controlled, two-by-two factorial trial with 6-month follow-up, conducted 1999 - 2002 in Tucson, Arizona. Patients were aged 12-60 months with recurrent otitis media, defined as three or more separate episodes of acute otitis media within six months, or at least four episodes in one year. Ninety children (44% white non-Hispanic, 39% Hispanic, 57% male) were enrolled, of which 84 had follow-up for at least 3 months. Children were randomly assigned to one of four protocol groups: double placebo, echinacea plus sham OMT, true OMT (including cranial manipulation) plus placebo echinacea, or true echinacea plus OMT. An alcohol extract of Echinacea purpurea roots and seeds (or placebo) was administered for 10 days at the first sign of each common cold. Five OMT visits (or sham treatments) were offered over 3 months. No interaction was found between echinacea and OMT. Echinacea was associated with a borderline increased risk of having at least one episode of acute otitis media during 6-month follow-up compared to placebo (65% versus 41%; relative risk, 1.59, 95% CI 1.04, 2.42). OMT did not significantly affect risk compared to sham (44% versus 61%; relative risk, 0.72, 95% CI 0.48, 1.10). In otitis-prone young children, treating colds with this form of echinacea does not decrease the risk of acute otitis media, and may in fact increase risk. A regimen of up to five osteopathic manipulative treatments does not significantly decrease the risk of acute otitis media. ClinicalTrials.gov Identifier: NCT00010465.

  6. Determination of polyphenols and free radical scavenging activity of Tephrosia purpurea linn leaves (Leguminosae

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    Avani Patel

    2010-01-01

    Full Text Available Background: Leaves of Tephrosia purpurea Linn. (sarpankh, belonging to the family Leguminaceae, are used for the treatment of jaundice and are also claimed to be effective in many other diseases. This research work was undertaken to investigate the in vitro antioxidant activity of aqueous and ethanolic extracts of the leaves. Method: The therapeutic effects of tannins and flavonoids can be largely attributed to their antioxidant properties. So, the quantitative determinations were undertaken. All the methods are based on UV-spectrophotometric determination. Result: The total phenolic content of aqueous and ethanolic extracts showed the content values of 9.44 ± 0.22% w/w and 18.44 ± 0.13% w/w, respectively, and total flavonoid estimation of aqueous and ethanolic extracts showed the content values of 0.91 ± 0.08% w/w and 1.56 ± 0.12%w/w, respectively, for quercetin and 1.85 ± 0.08% w/w and 2.54 ± 0.12% w/w, respectively, for rutin. Further investigations were carried out for in vitro antioxidant activity and radical scavenging activity by calculating its percentage inhibition by means of IC 50 values, all the extracts′ concentrations were adjusted to fall under the linearity range and here many reference standards like tannic acid, gallic acid, quercetin, ascorbic acid were taken for the method suitability. Conclusion: The results revealed that leaves of this plant have antioxidant potential. The results also show the ethanolic extract to be more potent than the aqueous decoction which is claimed traditionally. In conclusion, T. purpurea Linn. (Leguminosae leaves possess the antioxidant substance which may be responsible for the treatment of jaundice and other oxidative stress-related diseases.

  7. PERMANENCE OF A NONLINEAR PERIODIC PREDATOR-PREY SYSTEM WITH PREY DISPERSAL AND PREDATOR DENSITY-INDEPENDENCE

    Institute of Scientific and Technical Information of China (English)

    Lijuan Chen; Junyan Xu

    2009-01-01

    In this paper,a set of sufficient conditions which ensure the permanence of a nonlinear periodic predator-prey system with prey dispersal and predator density-independence are obtained,where the prey species can disperse among n patches,while the density-independent predator is confined to one of the patches and cannot disperse. Our results generalize some known results.

  8. Bifurcation and Limit Cycle of a Ratio-dependent Predator-prey System with Refuge on Prey

    Institute of Scientific and Technical Information of China (English)

    LIU Yan-wei; LIU Xia

    2013-01-01

    Influences of prey refuge on the dynamics of a predator-prey model with ratiodependent functional response are investigated.The local and global stability of positive equilibrium of the system are considered.Theoretical analysis indicates that constant refuge leads to the system undergo supercritical Hopf bifurcation twice with the birth rate of prey species changing continuously.

  9. PERMANENCE OF A NONLINEAR PERIODIC PREDATOR-PREY SYSTEM WITH PREY DISPERSAL AND PREDATOR DENSITY-INDEPENDENCE

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    In this paper,a set of suffcient conditions which ensure the permanence of a nonlinear periodic predator-prey system with prey dispersal and predator density-independence are obtained,where the prey species can disperse among n patches,while the density-independent predator is confined to one of the patches and cannot disperse. Our results generalize some known results.

  10. Effects of supplemented diets by levamisole and Echinacea purpurea extract on growth and reproductive parameters in angelfish (Pterophyllum scalare

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    Milad Kasiri

    2011-01-01

    Full Text Available The aim of this study was evaluation the effects of supplemented diets by levamisole andEchinacea purpurea (Moench, 1794 extract on growth and reproductive parameters in angelfish,Pterophyllum scalare (Lictenstein, 1823. 54 Uniform angelfish (average weight 3.8±0.29 g wereselected. The fishes were fed by three diets which included commercial extruder diet (control,commercial extruder diet supplemented by 0.25 ppt levamisole (T1 and commercial extruder dietsupplemented by 0.25 ppt Echinacea purpurea extract (T2. The experiment was conducted for 3 months.The weight gain in T2 was significantly higher than other groups (p0.05 in fecundity and hatching rate among groups but the best survival of yolk-sacabsorption period was found in group fed supplemented diet by Echinacea extract (pEchinacea extract supplementation andlarval survival can be promoted by it.

  11. Predator personality and prey behavioural predictability jointly determine foraging performance

    Science.gov (United States)

    Chang, Chia-chen; Teo, Huey Yee; Norma-Rashid, Y.; Li, Daiqin

    2017-01-01

    Predator-prey interactions play important roles in ecological communities. Personality, consistent inter-individual differences in behaviour, of predators, prey or both are known to influence inter-specific interactions. An individual may also behave differently under the same situation and the level of such variability may differ between individuals. Such intra-individual variability (IIV) or predictability may be a trait on which selection can also act. A few studies have revealed the joint effect of personality types of both predators and prey on predator foraging performance. However, how personality type and IIV of both predators and prey jointly influence predator foraging performance remains untested empirically. Here, we addressed this using a specialized spider-eating jumping spider, Portia labiata (Salticidae), as the predator, and a jumping spider, Cosmophasis umbratica, as the prey. We examined personality types and IIVs of both P. labiata and C. umbratica and used their inter- and intra-individual behavioural variation as predictors of foraging performance (i.e., number of attempts to capture prey). Personality type and predictability had a joint effect on predator foraging performance. Aggressive predators performed better in capturing unpredictable (high IIV) prey than predictable (low IIV) prey, while docile predators demonstrated better performance when encountering predictable prey. This study highlights the importance of the joint effect of both predator and prey personality types and IIVs on predator-prey interactions. PMID:28094288

  12. Effects of uniform rotational flow on predator-prey system

    Science.gov (United States)

    Lee, Sang-Hee

    2012-12-01

    Rotational flow is often observed in lotic ecosystems, such as streams and rivers. For example, when an obstacle interrupts water flowing in a stream, energy dissipation and momentum transfer can result in the formation of rotational flow, or a vortex. In this study, I examined how rotational flow affects a predator-prey system by constructing a spatially explicit lattice model consisting of predators, prey, and plants. A predation relationship existed between the species. The species densities in the model were given as S (for predator), P (for prey), and G (for plant). A predator (prey) had a probability of giving birth to an offspring when it ate prey (plant). When a predator or prey was first introduced, or born, its health state was assigned an initial value of 20 that subsequently decreased by one with every time step. The predator (prey) was removed from the system when the health state decreased to less than zero. The degree of flow rotation was characterized by the variable, R. A higher R indicates a higher tendency that predators and prey move along circular paths. Plants were not affected by the flow because they were assumed to be attached to the streambed. Results showed that R positively affected both predator and prey survival, while its effect on plants was negligible. Flow rotation facilitated disturbances in individuals’ movements, which consequently strengthens the predator and prey relationship and prevents death from starvation. An increase in S accelerated the extinction of predators and prey.

  13. Quantitative molecular diagnostic assays of grain washes for Claviceps purpurea are correlated with visual determinations of ergot contamination

    Science.gov (United States)

    Comte, Alexia; Gräfenhan, Tom; Links, Matthew G.; Hemmingsen, Sean M.

    2017-01-01

    We examined the epiphytic microbiome of cereal grain using the universal barcode chaperonin-60 (cpn60). Microbial community profiling of seed washes containing DNA extracts prepared from field-grown cereal grain detected sequences from a fungus identified only to Class Sordariomycetes. To identify the fungal sequence and to improve the reference database, we determined cpn60 sequences from field-collected and reference strains of the ergot fungus, Claviceps purpurea. These data allowed us to identify this fungal sequence as deriving from C. purpurea, and suggested that C. purpurea DNA is readily detectable on agricultural commodities, including those for which ergot was not identified as a grading factor. To get a sense of the prevalence and level of C. purpurea DNA in cereal grains, we developed a quantitative PCR assay based on the fungal internal transcribed spacer (ITS) and applied it to 137 samples from the 2014 crop year. The amount of Claviceps DNA quantified correlated strongly with the proportion of ergot sclerotia identified in each grain lot, although there was evidence that non-target organisms were responsible for some false positives with the ITS-based assay. We therefore developed a cpn60-targeted loop-mediated isothermal amplification assay and applied it to the same grain wash samples. The time to positive displayed a significant, inverse correlation to ergot levels determined by visual ratings. These results indicate that both laboratory-based and field-adaptable molecular diagnostic assays can be used to detect and quantify pathogen load in bulk commodities using cereal grain washes. PMID:28257512

  14. Quantitative molecular diagnostic assays of grain washes for Claviceps purpurea are correlated with visual determinations of ergot contamination.

    Science.gov (United States)

    Comte, Alexia; Gräfenhan, Tom; Links, Matthew G; Hemmingsen, Sean M; Dumonceaux, Tim J

    2017-01-01

    We examined the epiphytic microbiome of cereal grain using the universal barcode chaperonin-60 (cpn60). Microbial community profiling of seed washes containing DNA extracts prepared from field-grown cereal grain detected sequences from a fungus identified only to Class Sordariomycetes. To identify the fungal sequence and to improve the reference database, we determined cpn60 sequences from field-collected and reference strains of the ergot fungus, Claviceps purpurea. These data allowed us to identify this fungal sequence as deriving from C. purpurea, and suggested that C. purpurea DNA is readily detectable on agricultural commodities, including those for which ergot was not identified as a grading factor. To get a sense of the prevalence and level of C. purpurea DNA in cereal grains, we developed a quantitative PCR assay based on the fungal internal transcribed spacer (ITS) and applied it to 137 samples from the 2014 crop year. The amount of Claviceps DNA quantified correlated strongly with the proportion of ergot sclerotia identified in each grain lot, although there was evidence that non-target organisms were responsible for some false positives with the ITS-based assay. We therefore developed a cpn60-targeted loop-mediated isothermal amplification assay and applied it to the same grain wash samples. The time to positive displayed a significant, inverse correlation to ergot levels determined by visual ratings. These results indicate that both laboratory-based and field-adaptable molecular diagnostic assays can be used to detect and quantify pathogen load in bulk commodities using cereal grain washes.

  15. Amelioration of cisplatin-induced nephrotoxicity by ethanolic extract of Bauhinia purpurea: An in vivo study in rats.

    Science.gov (United States)

    Rana, Md Azmat; Khan, Rahat Ali; Nasiruddin, Mohammad; Khan, Aijaz Ahmed

    2016-01-01

    Our objective is to study the nephroprotective activity and antioxidant potential of Bauhinia purpurea unripe pods and bark against cisplatin-induced nephrotoxicity. Healthy adult albino rats of either sex (150-200 g) were randomly divided into six groups of six animals each Group I (vehicle control) and Group II (negative control). Group III (BBE200) and Group IV (BBE400) were administered the ethanolic extract of Bauhinia purpurea bark in doses of 200 and 400 mg/kg/day p.o., respectively, and Group V (BPE200) and Group VI (BPE400) were administered the ethanolic extract of Bauhinia purpurea unripe pods at doses of 200 and 400 mg/kg/day p.o., respectively. All the treatments were given for nine days. Cisplatin in a single dose of 6 mg/kg i.p. was given on the 4 th day to all groups, except the vehicle control group. On the 10 th day, blood and urine were collected for biochemical tests and the rats were sacrificed. The kidney was removed for histology and lipid peroxidation-antioxidant test. Cisplatin caused nephrotoxicity as evidenced by elevated blood urea, serum creatinine and urine glucose, and there was decreased creatinine clearance in Group II as compared with Group I. Administration of BBE and BPE at doses of 200 and 400 mg/kg in Group III and Group VI caused a dose-dependant reduction in the rise of blood urea, serum creatinine and urine glucose, and there was a dose-dependant increase in creatinine clearance compared with Group II. There was increased catalase and glutathione and decreased malondialdehyde levels in Group II, while BBE 400 (Group IV) and BPE 400 (Group VI) treatments significantly reversed the changes toward normal values. Histological examination of the kidney revealed protection in Group IV and Group VI compared with Group II. The ethanolic extract of Bauhinia purpurea unripe pods and bark has a nephroprotective activity against cisplatin-induced nephrotoxicity in rats.

  16. Estimation of Flavonoid, Polyphenolic Content and In-vitro Antioxidant Capacity of leaves of Tephrosia purpurea Linn. (Leguminosae

    Directory of Open Access Journals (Sweden)

    Avani Patel

    2010-02-01

    Full Text Available Leaves of Tephrosia purpurea Linn (sarpankh, belonging to the family Leguminosae being used for the treatment of jaundice and claimed to be effective in many other diseases. The present research work wasunder taken to investigate the in-vitro antioxidant activity of aqueous and ethanolic extracts. Method The therapeutic effects of tannins and flavonoids can be largely attributed to their antioxidant properties. So that the quantitative determinations were undertaken. All the methods are based on UV-Spectrophotometric determination.

  17. An Integrated Field and Hyperspectral Remote Sensing Method for the Estimation of Pigments Content of Stipa Purpurea in Shenzha, Tibet

    Directory of Open Access Journals (Sweden)

    Bo Kong

    2017-01-01

    Full Text Available Stipa purpurea is the representative type of alpine grassland in Tibet and the surviving and development material for herdsmen. This paper takes Shenzha County as the research area. Based on the analysis of typical hyperspectral variables sensitive to chlorophyll content of Stipa purpurea, 10 spectral variables with significant correlation with chlorophyll were extracted. The estimation model of chlorophyll was established. The photosynthetic pigment contents in the Shenzha area were calculated by using HJ-1A remote sensing images. The results show that (1 there are significant correlations between chlorophyll content and spectral variables; in particular, the coefficient of Chlb in Stipa purpurea with RVI is the largest (0.728; (2 10 variables are correlated with chlorophyll, and the order of correlation is Chlb > Chla > Chls; (3 for the estimation of Chla, the EVI is the best variable. RVI, NDVI, and VI2 are suitable for Chlb; RVI and NDVI are also suitable for the estimation of Chls; (4 the mean estimated content of Chla in Stipa bungeana is about 4.88 times that of Chlb, while Cars is slightly more than Chlb; (5 the distribution of Chla is opposite to Chlb and Chls content in water area.

  18. Effect of dietary supplementation with Echinacea purpurea on vaccine efficacy against infection with Flavobacterium columnare in zebrafish (Danio rerio).

    Science.gov (United States)

    Guz, L; Puk, K; Walczak, N; Oniszczuk, T; Oniszczuk, A

    2014-01-01

    The effect of dietary Echinacea purpurea (EP) on the response of zebrafish (Danio rerio) to a Flavobacterium columnare vaccine was investigated. Two hundred D. rerio with an average weight of 290 ± 40 g were selected and fed different levels of E. purpurea (5 g kg(-1) diet--group 1, 10 g kg(-1) diet--group 2, 20 g kg(-1) diet--group 3, 30 g kg(-1) diet--group 4, and 0 g kg(-1) diet--group 5). Experimental feeding was begun 3 weeks prior to bath immunization and continued until the end of the experiment. Twenty-eight days after immunization the fish were challenged by bath immersion with F. columnare at a concentration of 1 x 10(6) CFU/ml. The relative percent survival of the experimental groups (1, 2, 3, 4 and 5) was 5.0, 6.0, 30.0, 36.0 and 5.0, respectively. In conclusion, diet supplementation with E. purpurea may effectively enhance the response of zebrafish to a F. columnare vaccine.

  19. Antioxidant, Antidiabetic, and Antihypertensive Properties of Echinacea purpurea Flower Extract and Caffeic Acid Derivatives Using In Vitro Models.

    Science.gov (United States)

    Chiou, Shiow-Ying; Sung, Jih-Min; Huang, Po-Wei; Lin, Sheng-Dun

    2017-02-01

    The extraction yield, total phenols, caffeic acid derivatives (CAD), and antioxidant properties of 50% ethanolic Echinacea purpurea flower extract were determined. The in vitro inhibitory effects of 50% ethanolic extract and CAD on α-amylase, α-glucosidase, and angiotensin-converting enzyme (ACE) linked with type 2 diabetes were also investigated. The extraction yield, total phenols, and total CAD of the extract were 27.04%, 195.69 mg CAE/g and 78.42 mg/g, respectively. Cichoric acid (56.03 mg/g) was the predominant CAD compound in the extract. The extract exhibited good antioxidant properties. The extract and CAD inhibited α-amylase, α-glucosidase, and ACE activities in a concentration-dependent manner. Among the tested samples, chlorogenic acid, and caffeic acid (IC50 of 1.71-1.81 mg/mL) had the highest α-amylase inhibitory activity, cichoric acid (IC50 of 0.28 mg/mL) showed higher α-glucosidase inhibitory activity. Both chlorogenic acid and caffeic acid (IC50 of 0.11-0.14 mg/mL) demonstrated higher ACE-inhibitory activity. The in vitro results suggest that E. purpurea extract and CAD have good potential for managing hyperglycemia and hypertension. Overall, the data suggest it is a choice for developing antihyperglycemia and antihypertension compounds from field-grown E. purpurea.

  20. Tephrosia purpurea ameliorates N-diethylnitrosamine and potassium bromate-mediated renal oxidative stress and toxicity in Wistar rats.

    Science.gov (United States)

    Khan, N; Sharma, S; Alam, A; Saleem, M; Sultana, S

    2001-06-01

    In an earlier communication, we have shown that Tephrosia purpurea ameliorates benzoyl peroxide-induced oxidative stress in murine skin (Saleem et al. 1999). The present study was designed to investigate a chemopreventive efficacy of T purpurea against N-diethylnitrosamine-initiated and potassium bromate-mediated oxidative stress and toxicity in rat kidney. A single intraperitoneal dose of N-diethylnitrosamine (200 mg/kg body weight) one hr prior to the dose of KBrO3 (125 mg/kg body weight) increases microsomal lipid peroxidation and the activity of xanthine oxidase and decreases the activities of renal antioxidant enzymes viz., catalase, glutathione peroxidase, glutathione reductase and glucose-6-phosphate dehydrogenase, phase II metabolizing enzymes such as glutathione-S-transferase and quinone reductase and causes depletion in the level of renal glutathione content. A sharp increase in blood urea nitrogen and serum creatinine has also been observed. Prophylactic treatment of rats with T. purpurea at doses of 5 mg/kg body weight and 10 mg/kg body weight prevented N-diethylnitrosamine-initiated and KBrO3 promoted renal oxidative stress and toxicity. The susceptibility of renal microsomal membrane for iron ascorbate-induced lipid peroxidation and xanthine oxidase activities were significantly reduced (Ppurpurea besides a skin antioxidant can be a potent chemopreventive agent against renal oxidative stress and carcinogenesis induced by N-diethylnitrosamine and KBrO3.

  1. A focus on long-run sustainability of a harvested prey predator system in the presence of alternative prey.

    Science.gov (United States)

    Kar, T K; Chattopadhyay, S K

    2010-01-01

    Within the framework of a general equilibrium model we study the long-run dynamics of a prey-predator model in the presence of an alternative prey. Our results show that sustainability, i.e. a positive value of the population in the long run, essentially depends on individual harvesting efforts and digesting factors relative to alternative prey. A detailed bifurcation analysis evidences the richness of possible long-run dynamics. Our model clearly shows that the role of an alternative prey must be taken into consideration when studying prey-predator dynamics.

  2. Predator-prey interactions mediated by prey personality and predator hunting mode.

    Science.gov (United States)

    Belgrad, Benjamin A; Griffen, Blaine D

    2016-04-13

    Predator-prey interactions are important drivers in structuring ecological communities. However, despite widespread acknowledgement that individual behaviours and predator species regulate ecological processes, studies have yet to incorporate individual behavioural variations in a multipredator system. We quantified a prevalent predator avoidance behaviour to examine the simultaneous roles of prey personality and predator hunting mode in governing predator-prey interactions. Mud crabs, Panopeus herbstii, reduce their activity levels and increase their refuge use in the presence of predator cues. We measured mud crab mortality and consistent individual variations in the strength of this predator avoidance behaviour in the presence of predatory blue crabs, Callinectes sapidus, and toadfish, Opsanus tau We found that prey personality and predator species significantly interacted to affect mortality with blue crabs primarily consuming bold mud crabs and toadfish preferentially selecting shy crabs. Additionally, the strength of the predator avoidance behaviour depended upon the predation risk from the predator species. Consequently, the personality composition of populations and predator hunting mode may be valuable predictors of both direct and indirect predator-prey interaction strength. These findings support theories postulating mechanisms for maintaining intraspecies diversity and have broad implications for community dynamics.

  3. Echinacea purpurea significantly induces cytochrome P450 3A activity but does not alter lopinavir-ritonavir exposure in healthy subjects.

    Science.gov (United States)

    Penzak, Scott R; Robertson, Sarah M; Hunt, Jennifer D; Chairez, Cheryl; Malati, Christine Y; Alfaro, Raul M; Stevenson, James M; Kovacs, Joseph A

    2010-08-01

    . To determine the influence of Echinacea purpurea on the pharmacokinetics of lopinavir-ritonavir and on cytochrome P450 (CYP) 3A and P-glycoprotein activity by using the probe substrates midazolam and fexofenadine, respectively. Open-label, single-sequence pharmacokinetic study. Outpatient clinic in a federal government research center. Thirteen healthy volunteers (eight men, five women). Subjects received lopinavir 400 mg-ritonavir 100 mg twice/day with meals for 29.5 days. On day 16, subjects received E. purpurea 500 mg 3 times/day for 28 days: 14 days in combination with lopinavir-ritonavir and 14 days of E. purpurea alone. In order to assess CYP3A and P-glycoprotein activity, subjects received single oral doses of midazolam 8 mg and fexofenadine 120 mg, respectively, before and after the 28 days of E. purpurea. On days 15 and 30 of lopinavir-ritonavir administration (before and after E. purpurea administration, respectively), serial blood samples were collected over 12 hours to determine lopinavir and ritonavir concentrations and subsequent pharmacokinetic parameters by using noncompartmental methods. Neither lopinavir nor ritonavir pharmacokinetics were significantly altered by 14 days of E. purpurea coadministration. The post-echinacea: pre-echinacea geometric mean ratios (GMRs) for lopinavir area under the concentration-time curve (AUC) from 0-12 hours and for maximum concentration were 0.96 (90% confidence interval [CI] 0.83-1.10, p=0.82) and 1.00 (90% CI 0.88-1.12, p=0.72), respectively. Conversely, GMRs for midazolam AUC from time zero extrapolated to infinity and oral clearance were 0.73 (90% CI 0.61-0.85, p=0.008) and 1.37 (90% CI 1.10-1.63, p=0.02), respectively. Fexofenadine pharmacokinetics did not significantly differ before and after E. purpurea administration (p>0.05). Echinacea purpurea induced CYP3A activity but did not alter lopinavir concentrations, most likely due to the presence of the potent CYP3A inhibitor, ritonavir. Echinacea purpurea

  4. Quality Assessment of Serially Ultradiluted and Agitated Drug Digitalis purpurea by Emission Spectroscopy and Clinical Analysis of Its Effect on the Heart Rate of Indian Bufo melanostictus

    Directory of Open Access Journals (Sweden)

    Anup Sharma

    2013-01-01

    Full Text Available The investigation of ultradiluted (homeopathic drugs is extremely interesting and challenging, and from that point of view this study shows novelty. A study of in vivo changes in heart rate of the Indian Bufo melanostictus caused by commercially available serially ultra-diluted and agitated extract of Digitalis purpurea has been tried in order to understand their pharmacological role. RR interval (of ECG was compared after intraperitoneal administration of serially diluted and agitated Digitalis purpurea extract, diluent rectified spirit, and Digoxin in anesthetized animals. The study revealed statistically significant changes in the heart rate after application of these drugs except in case of Digoxin and the 200th serial dilution of Digitalis purpurea. The duration of RR intervals after application of the drugs was corroborative of the effect of Digoxin and Digitalis purpurea extract up to 30th dilution. Emission spectra were obtained for the experimental ultra-diluted Digitalis purpurea extract and Digoxin to identify and characterize them. The observed RR pattern and emission spectra show an association. The quality assessment of the commercial ultra-diluted organic drugs obtained from natural products may be initiated by monitoring in vivo studies on animal models.

  5. Assessment of the effect of Echinacea purpurea (L.) Moench on apoptotic and mitotic activity of liver cells during intoxication by cadmium.

    Science.gov (United States)

    Smalinskiene, Alina; Lesauskaite, Vaiva; Ryselis, Stanislovas; Abdrakhmanov, Oleg; Kregzdyte, Rima; Sadauskiene, Ilona; Ivanov, Leonid; Savickiene, Nijole; Zitkevicius, Virgilijus; Savickas, Arunas

    2007-01-01

    Cadmium (Cd(2+)) is an important industrial pollutant, although its mechanism of toxicity has not been completely clarified. Cd(2+) is toxic to a wide range of organs and tissues, however, the primary target organs of Cd(2+) toxicity are the liver and kidney. Echinacea purpurea stimulating one or another tread of the immune system stimulates the expression of immunoglobulins and interferons. The experiments were performed on white laboratory mice using intraperitoneal (i.p.) injections 0.05 LD(50) amount of CdCl(2) solution. Two groups of mice were injected by Echinacea purpurea liquid extract: one 0.05 LD(50) and the other 0.1 LD(50). In this article, the Cd(2+) distribution in internal organs, its effect on the mitotic and apoptotic activity of liver cells, as well as effects of Echinacea purpurea liquid extract on Cd(2+)-induced changes in mice were investigated. Cd(2+) concentration in mice blood, liver, and kidney was detected by atomic absorption spectroscopy. Long-term injections of extract of Echinacea purpurea combined with Cd(2+)Cl(2) leads to the significant increase of Cd(2+) concentration in blood and investigated organs of experimental mice. Mitotic and apoptotic activity of liver cells was expressed as the estimated number of mitotic and apoptotic liver cells in randomly selected reference areas in histological slide. Echinacea purpurea decreases the mitotic activity of liver cells induced by Cd(2+) and increases apoptotic activity of the liver cells.

  6. In vitro inhibition of CYP3A4 by the multiherbal commercial product Sambucus Force and its main constituents Echinacea purpurea and Sambucus nigra.

    Science.gov (United States)

    Schrøder-Aasen, Torstein; Molden, Guri; Nilsen, Odd Georg

    2012-11-01

    The multiherbal product Sambucus Force contains Echinacea purpurea and Sambucus nigra as its main constituents. The aims of this study were to evaluate Sambucus Force's inhibition potential and inhibition mechanisms towards CYP3A4, and to evaluate the inhibitory co-contribution of E. purpurea and S. nigra. Metabolic studies were performed with recombinant human CYP3A4, with testosterone as substrate. Sambucus Force inhibited CYP3A4 activity with a mean (95% confidence interval) half maximal inhibitory concentration (IC(50) ) value of 1192 (1091-1302) µg/mL. The inhibitory potency seems exclusively to be exerted by E. purpurea, implicating an insignificant inhibition by S. nigra. The inhibition by E. purpurea as a single herb was in agreement with mechanism-based inhibition with heterotropic positive cooperative effects. Echinacea purpurea acted differently in the multiherbal product, which showed a dual inhibition profile with both an uncompetitive (substrate-dependent) inhibition and a time-dependent (substrate-independent) inhibitory mechanism. These mechanistic differences are suggested to be caused by herb-herb interactions in the multiherbal product. The CYP3A4 inhibition of Sambucus Force in vitro is considered relatively weak, but recommended high herbal dosages might enhance the potential for clinical interactions. Copyright © 2012 John Wiley & Sons, Ltd.

  7. Diet of Chinese skink, Eumeces chinensis: is prey size important?

    Science.gov (United States)

    Chen, Xiaolin; Jiang, Yong

    2006-06-01

    The diet of the skink, Eumeces chinensis (Lacertilia: Scincidae), in Xiamen (Amoy), China was examined using stomach analysis during April and May, and its selection of prey size was tested by feeding trials. Insects (primarily Coleoptera, Lepidoptera, and Orthoptera), gastropods and arachnids constituted most of the E. chinensis diet, but earthworms, leeches, crustaceans and fish were also consumed. In the field, male skinks ate more prey items that were 11-20 mm in length than other size classes. When presented with a choice of different-sized prey in the laboratory, male E. chinensis exhibited a strong preference for prey items 11-20 mm in length over other size classes. The relationship between prey size and handling time was exponential, indicating that there is an upper limit to the ability of E. chinensis to process prey. Mean energy intake for handling different-sized prey showed that selection of midsizeclass prey items would provide male E. chinensis with the most energy-efficient prey option. These results indicate that prey size selection in E. chinensis favors maximization of rates of energy intake, which is in agreement with optimal foraging theory.

  8. Dynamics of a Delayed Predator-prey System with Stage Structure for Predator and Prey

    Institute of Scientific and Technical Information of China (English)

    Liu Juan; Zhang Zi-zhen

    2015-01-01

    In this paper, a predator-prey system with two discrete delays and stage structure for both the predator and the prey is investigated. The dynamical be-haviors such as local stability and local Hopf bifurcation are analyzed by regarding the possible combinations of the two delays as bifurcating parameter. Some explicit formulae determining the direction of the Hopf bifurcation and the stability of the bifurcating periodic solutions are derived by using the normal form method and the center manifold theory. Finally, numerical simulations are presented to support the theoretical analysis.

  9. Patterns of prey capture and prey availability among populations of the carnivorous plant Pinguicula moranensis (Lentibulariaceae) along an environmental gradient.

    Science.gov (United States)

    Alcalá, Raúl E; Domínguez, César A

    2003-09-01

    In this study we explored the effect of the physical environment and the availability of prey (biomass and taxonomic composition) on the patterns of prey capture and reproduction on five populations of Pinguicula moranensis (Lentibulariaceae) in areas ranging from pine-oak forests to desert scrublands. Environmental variation was summarized using principal factor analysis. Prey availability and prey capture increased toward the shadiest, most humid, and fertile population. The probability of reproduction and average bud production per population did not follow the same tendency because both fitness components peaked at the middle of the environmental gradient. These results suggest that the benefits derived from carnivory are maximized at sites fulfilling a trade-off between light, moisture, and prey availability. We also found that the taxonomic composition of both the available prey and that of the prey captured by plants varied among populations. The results also indicated that the prey captured by plants are not a random sample of prey available within populations. Overall, the results from this study revealed a marked amount of heterogeneity in the physical and biotic environment among the populations of P. moranensis, which has the potential to affect the outcome of the interaction between this carnivorous species and its prey.

  10. A single predator charging a herd of prey: effects of self volume and predator-prey decision-making

    CERN Document Server

    Schwarzl, M; Oshanin, G; Metzler, R

    2016-01-01

    We study the degree of success of a single predator hunting a herd of prey on a two dimensional square lattice landscape. We explicitly consider the self volume of the prey restraining their dynamics on the lattice. The movement of both predator and prey is chosen to include an intelligent, decision making step based on their respective sighting ranges, the radius in which they can detect the other species (prey cannot recognise each other besides the self volume interaction): after spotting each other the motion of prey and predator turns from a nearest neighbour random walk into direct escape or chase, respectively. We consider a large range of prey densities and sighting ranges and compute the mean first passage time for a predator to catch a prey as well as characterise the effective dynamics of the hunted prey. We find that the prey's sighting range dominates their life expectancy and the predator profits more from a bad eyesight of the prey than from his own good eye sight. We characterise the dynamics ...

  11. Echinacea purpurea and osteopathic manipulative treatment in children with recurrent otitis media: a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Worden Katherine A

    2008-10-01

    Full Text Available Abstract Background Recurrent otitis media is a common problem in young children. Echinacea and osteopathic manipulative treatment have been proposed as preventive measures, but have been inadequately studied. This study was designed to assess the efficacy of Echinacea purpurea and/or osteopathic manipulative treatment (OMT for prevention of acute otitis media in otitis-prone children. Methods A randomized, placebo-controlled, two-by-two factorial trial with 6-month follow-up, conducted 1999 – 2002 in Tucson, Arizona. Patients were aged 12–60 months with recurrent otitis media, defined as three or more separate episodes of acute otitis media within six months, or at least four episodes in one year. Ninety children (44% white non-Hispanic, 39% Hispanic, 57% male were enrolled, of which 84 had follow-up for at least 3 months. Children were randomly assigned to one of four protocol groups: double placebo, echinacea plus sham OMT, true OMT (including cranial manipulation plus placebo echinacea, or true echinacea plus OMT. An alcohol extract of Echinacea purpurea roots and seeds (or placebo was administered for 10 days at the first sign of each common cold. Five OMT visits (or sham treatments were offered over 3 months. Results No interaction was found between echinacea and OMT. Echinacea was associated with a borderline increased risk of having at least one episode of acute otitis media during 6-month follow-up compared to placebo (65% versus 41%; relative risk, 1.59, 95% CI 1.04, 2.42. OMT did not significantly affect risk compared to sham (44% versus 61%; relative risk, 0.72, 95% CI 0.48, 1.10. Conclusion In otitis-prone young children, treating colds with this form of echinacea does not decrease the risk of acute otitis media, and may in fact increase risk. A regimen of up to five osteopathic manipulative treatments does not significantly decrease the risk of acute otitis media. Trial registration ClinicalTrials.gov Identifier: NCT00010465

  12. PHARMACOBOTANICAL STUDIES ON 'SHVET SHARPUNKHA' - A COMPARATIVE DIAGNOSTIC ACCOUNT OF TEPHROSIA VILLOSA PERS. AND T. PURPUREA (LINN.) PERS. FORM ALBIFLORA S. R. PAUL et. R. C. GUPTA.

    Science.gov (United States)

    Gupta, R C

    1988-01-01

    Two kinds of 'shapunkha', the 'Shvet' (white) and 'Rakta' (red) are described in some of the Ayurvedic texts and the former is reported therapeutically more effective. Some of the Ayurvedic physicians use T. villosa Pers. as 'Shvet sharpunkha' due to its persistently villous silky white parts. While others have advocated white colour of flowers as main feature for distinguishing "Shvet sharpunkha'. A white flowered form of Tephrosia purpurea which is found in association with red or purple flowered ones is reported by us as T. purpurea (Linn.) Pers. Form albiflora S. R. Paul et R. C. Gupta. In the present work, however, detailed comparative pharmacognosy of all vegetable parts of T. villosa and T. purpurea f. albiflora have been carried out. Also the study reveals that two species exhibit great similarity in their macro - an microscopical feature.

  13. Prey selectivity affects reproductive success of a corallivorous reef fish.

    Science.gov (United States)

    Brooker, Rohan M; Jones, Geoffrey P; Munday, Philip L

    2013-06-01

    Most animals consume a narrower range of food resources than is potentially available in the environment, but the underlying basis for these preferences is often poorly understood. Foraging theory predicts that prey selection should represent a trade-off between prey preferences based on nutritional value and prey availability. That is, species should consume preferred prey when available, but select less preferred prey when preferred prey is rare. We employed both field observation and laboratory experiments to examine the relationship between prey selection and preferences in the obligate coral-feeding filefish, Oxymonacanthus longirostris. To determine the drivers of prey selection, we experimentally established prey preferences in choice arenas and tested the consequences of prey preferences for key fitness-related parameters. Field studies showed that individuals fed almost exclusively on live corals from the genus Acropora. While diet was dominated by the most abundant species, Acropora nobilis, fish appeared to preferentially select rarer acroporids, such as A. millepora and A. hyacinthus. Prey choice experiments confirmed strong preferences for these corals, suggesting that field consumption is constrained by availability. In a longer-term feeding experiment, reproductive pairs fed on non-preferred corals exhibited dramatic reductions to body weight, and in hepatic and gonad condition, compared with those fed preferred corals. The majority of pairs fed preferred corals spawned frequently, while no spawning was observed for any pairs fed a non-preferred species of coral. These experiments suggest that fish distinguish between available corals based on their intrinsic value as prey, that reproductive success is dependent on the presence of particular coral species, and that differential loss of preferred corals could have serious consequences for the population success of these dietary specialists.

  14. Prey Selection of Scandinavian Wolves: Single Large or Several Small?

    Science.gov (United States)

    Sand, Håkan; Eklund, Ann; Zimmermann, Barbara; Wikenros, Camilla; Wabakken, Petter

    2016-01-01

    Research on large predator-prey interactions are often limited to the predators' primary prey, with the potential for prey switching in systems with multiple ungulate species rarely investigated. We evaluated wolf (Canis lupus) prey selection at two different spatial scales, i.e., inter- and intra-territorial, using data from 409 ungulate wolf-kills in an expanding wolf population in Scandinavia. This expansion includes a change from a one-prey into a two-prey system with variable densities of one large-sized ungulate; moose (Alces alces) and one small-sized ungulate; roe deer (Capreolus capreolus). Among wolf territories, the proportion of roe deer in wolf kills was related to both pack size and roe deer density, but not to moose density. Pairs of wolves killed a higher proportion of roe deer than did packs, and wolves switched to kill more roe deer as their density increased above a 1:1 ratio in relation to the availability of the two species. At the intra-territorial level, wolves again responded to changes in roe deer density in their prey selection whereas we found no effect of snow depth, time during winter, or other predator-related factors on the wolves' choice to kill moose or roe deer. Moose population density was only weakly related to intra-territorial prey selection. Our results show that the functional response of wolves on moose, the species hitherto considered as the main prey, was strongly dependent on the density of a smaller, alternative, ungulate prey. The impact of wolf predation on the prey species community is therefore likely to change with the composition of the multi-prey species community along with the geographical expansion of the wolf population.

  15. Birds of Prey: Training Solutions to Human Factors Issues

    Science.gov (United States)

    2007-11-01

    Interservice/Industry Training, Simulation, and Education Conference (I/ITSEC) 2007 2007 Paper No. 7133 Page 1 of 12 Birds of Prey: Training...2007 2. REPORT TYPE Conference Proceedings 3. DATES COVERED 01-01-2006 to 30-11-2007 4. TITLE AND SUBTITLE Birds of Prey: Training Solutions...ITSEC) 2007 2007 Paper No. 7133 Page 3 of 12 Birds of Prey: Training Solutions to Human Factors Issues Robert T. Nullmeyer Air Force Research

  16. Venus Flytrap Seedlings Show Growth-Related Prey Size Specificity

    Directory of Open Access Journals (Sweden)

    Christopher R. Hatcher

    2014-01-01

    Full Text Available Venus flytrap (Dionaea muscipula has had a conservation status of vulnerable since the 1970s. Little research has focussed on the ecology and even less has examined its juvenile stages. For the first time, reliance on invertebrate prey for growth was assessed in seedling Venus flytrap by systematic elimination of invertebrates from the growing environment. Prey were experimentally removed from a subset of Venus flytrap seedlings within a laboratory environment. The amount of growth was measured by measuring trap midrib length as a function of overall growth as well as prey spectrum. There was significantly lower growth in prey-eliminated plants than those utilising prey. This finding, although initially unsurprising, is actually contrary to the consensus that seedlings (traps < 5 mm do not catch prey. Furthermore, flytrap was shown to have prey specificity at its different growth stages; the dominant prey size for seedlings did not trigger mature traps. Seedlings are capturing and utilising prey for nutrients to increase their overall trap size. These novel findings show Venus flytrap to have a much more complex evolutionary ecology than previously thought.

  17. Behavior of prey links midwater and demersal piscivorous reef fishes

    Directory of Open Access Journals (Sweden)

    Peter J. Auster

    Full Text Available Pelagic and demersal guilds of piscivorous fishes are linked by a variety of biological and physical processes that mediate interactions with common prey species. Understanding the behaviors of predators and prey can provide insight into the conditions that make such linkages possible. Here we report on the behaviors of mid-water piscivorous fishes and the responses of prey that produce feeding opportunities for demersal piscivorous fishes associated with "live bottom" ledge habitats off the coast of Georgia (northwest Atlantic Ocean. Prey taxa reduced nearest neighbor distances and retreated towards the seafloor during predatory attacks by mid-water fishes. Demersal fishes subsequently attacked and consumed prey in these ephemeral high density patches. No predation by demersal fishes was observed when prey species were at background densities. If the predator-prey interactions of demersal piscivorous fishes are commonly mediated by the predatory behavior of midwater piscivorous fishes and their prey, such indirect facilitative behaviors may be important in terms of the population processes (e.g., prey consumption and growth rates of these demersal fishes.

  18. Prey processing in the Siamese fighting fish (Betta splendens).

    Science.gov (United States)

    Konow, Nicolai; Krijestorac, Belma; Sanford, Christopher P J; Boistel, Renauld; Herrel, Anthony

    2013-07-01

    We studied prey processing in the Siamese fighting fish (Betta splendens), involving slow, easily observed head-bobbing movements, which were compared with prey processing in other aquatic feeding vertebrates. We hypothesized that head-bobbing is a unique prey-processing behaviour, which alternatively could be structurally and functionally analogous with raking in basal teleosts, or with pharyngognathy in neoteleosts. Modulation of head-bobbing was elicited by prey with different motility and toughness. Head-bobbing involved sustained mouth occlusion and pronounced cranial elevation, similar to raking. However, the hyoid and pectoral girdle were protracted, and not retracted as in both raking and pharyngognathy. High-speed videofluoroscopy of hyoid movements confirmed that head-bobbing differs from other known aquatic prey-processing behaviours. Nevertheless, head-bobbing and other prey-processing behaviours converge on a recurrent functional theme in the trophic ecology of aquatic feeding vertebrates; the use of intraoral and oropharyngeal dentition surfaces to immobilize, reduce and process relatively large, tough or motile prey. Prey processing outside the pharyngeal region has not been described for neoteleosts previously, but morphological evidence suggests that relatives of Betta might use similar processing behaviours. Thus, our results suggest that pharyngognathy did not out-compete ancestral prey-processing mechanisms completely during the evolution of neoteleosts.

  19. Prey switching behaviour in the planktonic copepod Acartia tonsa

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; Saiz, E.; Viitasalo, M.

    1996-01-01

    . Based on earlier observations, we also hypothesized that turbulence changes food selection towards motile prey. We tested these hypotheses by examining feeding rates and behaviour in adult females of A. tonsa feeding in mixtures of 2 prey organisms, a diatom (Thalassiosira weissflogii) and a ciliate...... (Strombidium sulcatum). Our data demonstrate prey switching in A. tonsa, both in terms of behaviour and in terms of feeding rates on the alternative prey. The time allocated to ambush and suspension feeding changed with the composition of the food, and clearance of diatoms was, accordingly, negatively related...

  20. The Coevolution of "Tyrannosaurus" & Its Prey: Could "Tyrannosaurus" Chase down & Kill a "Triceratops" for Lunch?

    Science.gov (United States)

    May, S. Randolph

    2014-01-01

    Students will analyze the coevolution of the predator-prey relationships between "Tyrannosaurus rex" and its prey species using analyses of animal speeds from fossilized trackways, prey-animal armaments, adaptive behaviors, bite marks on prey-animal fossils, predator-prey ratios, and scavenger competition. The students will be asked to…

  1. Two Generalized Predator-Prey Models for Integrated Pest Management with Stage Structure and Disease in the Prey Population

    Directory of Open Access Journals (Sweden)

    Ruiqing Shi

    2013-01-01

    Full Text Available Stage-structured predator-prey models with disease in the prey are constructed. For the purpose of integrated pest management, two types of impulsive control strategies (impulsive release of infective prey and impulsive release of predator are used. For Case  1, infective prey applications are more frequent than releases of predator (natural enemies. For Case  2, predator (natural enemies releases are more frequent than infective prey applications. In both cases, we get the sufficient conditions for the global attractivity of the susceptible prey-eradication periodic solution. In addition, the persistence of the systems is also discussed. At last, the results are discussed and some possible future work is put forward.

  2. Feeding rates in the chaetognath Sagitta elegans : effects of prey size, prey swimming behaviour and small-scale turbulence

    DEFF Research Database (Denmark)

    Saito, H.; Kiørboe, Thomas

    2001-01-01

    distances. We develop a simple prey encounter rate model by describing the swimming prey as a 'force dipole' and assuming that a critical signal strength is required to elicit an attack. By fitting the model to the observations, a critical signal strength of 10(-2) cm s(-1) is estimated; this is very......The gut contents of Sagitta elegans were sampled twice daily (noon and midnight) during 9 days in October at an anchor station in the northern North Sea. Observations of the ambient prey field and of turbulent dissipation rates were collected simultaneously. The average number of prey per...... chaetognath was among the highest ever recorded, 0.57 +/- 0.10. Total gut content was independent of ambient prey concentration, suggesting that feeding rate was saturated. Clearance rates were estimated from gut contents and ambient prey concentrations and a literature-based estimate of digestion time...

  3. Rapid prey evolution can alter the structure of predator-prey communities

    NARCIS (Netherlands)

    Friman, V. -P.; Jousset, A.; Buckling, A.

    2014-01-01

    Although microevolution has been shown to play an important role in pairwise antagonistic species interactions, its importance in more complex communities has received little attention. Here, we used two Pseudomonas fluorescens prey bacterial strains (SBW25 and F113) and Tetrahymena thermophila prot

  4. Biogenic nano-scale silver particles by Tephrosia purpurea leaf extract and their inborn antimicrobial activity

    Science.gov (United States)

    Ajitha, B.; Ashok Kumar Reddy, Y.; Reddy, P. Sreedhara

    2014-03-01

    In this paper we report the green synthesis of silver nanoparticles (Ag NPs) using Tephrosia purpurea leaf extract. The biomolecules present in the leaf extract are responsible for the formation of Ag NPs and they found to play dual role of both reducing as well as capping agents. The high crystallinity of Ag NPs is evident from bright circular spot array of SAED pattern and diffraction peaks in XRD profile. The synthesized Ag NPs are found to be nearly spherical ones with size approximately ∼20 nm. FTIR spectrum evidences the presence of different functional groups of biomolecules participated in encapsulating Ag NPs and the possible mechanism of Ag NPs formation was also suggested. Appearance of yellow color and surface plasmon resonance (SPR) peak at 425 nm confirms the Ag NPs formation. PL spectra showed decrement in luminescence intensity at higher excitation wavelengths. Antimicrobial activity of Ag NPs showed better inhibitory activity towards Pseudomonas spp. and Penicillium spp. compared to other test pathogens using standard Kirby-Bauer disc diffusion assay.

  5. Use of ethylenediurea (EDU) to ameliorate ozone effects on purple coneflower (Echinacea purpurea)

    Energy Technology Data Exchange (ETDEWEB)

    Szantoi, Zoltan [School of Forestry and Wildlife Sciences, Auburn University, Auburn, AL 36849 (United States)], E-mail: szantzo@auburn.edu; Chappelka, Arthur H. [School of Forestry and Wildlife Sciences, Auburn University, Auburn, AL 36849 (United States)], E-mail: chappah@auburn.edu; Muntifering, Russell B. [Animal Sciences Department, Auburn University, Auburn, AL 36849 (United States)], E-mail: muntirb@auburn.edu; Somers, Greg L. [School of Forestry and Wildlife Sciences, Auburn University, Auburn, AL 36849 (United States)], E-mail: somergl@auburn.edu

    2007-11-15

    Purple coneflower plants (Echinacea purpurea) were placed into open-top chambers (OTCs) for 6 and 12 weeks in 2003 and 2004, respectively, and exposed to charcoal-filtered air (CF) or twice-ambient (2x) ozone (O{sub 3}) in 2003, and to CF, 2x or non-filtered (NF), ambient air in 2004. Plants were treated with ethylenediurea (EDU) weekly as a foliar spray. Foliar symptoms were observed in >95% of the plants in 2x-treated OTCs in both years. Above-ground biomass was not affected by 2x treatments in 2003, but root and total-plant biomass decreased in 2004. As a result of higher concentrations of select cell wall constituents (% ADF, NDF and lignin) nutritive quality was lower for plants exposed to 2x-O{sub 3} in 2003 and 2004 (26% and 17%, respectively). Significant EDU x O{sub 3} interactions for concentrations of cell wall constituents in 2003 indicated that EDU ameliorated O{sub 3} effects on nutritive quality. Interactions observed in 2004 were inconsistent. - EDU can potentially ameliorate negative effects of O{sub 3} on nutritive quality in purple coneflower.

  6. Induction of Tetraploids from Petiole Explants through Colchicine Treatments in Echinacea purpurea L.

    Directory of Open Access Journals (Sweden)

    Dahanayake Nilanthi

    2009-01-01

    Full Text Available Petiole explants were obtained from in vitro grown diploid (2x=22 Echinacea purpurea plantlets. Shoots were regenerated by culturing the explants on MS basal medium containing 0.3 mg/L benzyladenine (BA, 0.01 mg/L naphthaleneacetic acid (NAA and four concentrations (30, 60, 120, and 240 mg/L of colchicine for 30 days, or 120 mg/L of colchicine for various durations (7, 14, 21, and 28 days. The regenerated shoots were induced to root on MS basal medium with 0.01 mg/L NAA, and then the root-tips of the regenerated shoots were sampled for count of chromosome number. It was found that a treatment duration of >7 days was necessary for induction of tetraploid (4x=44 shoots, and treatment with 120 mg/L colchicine for 28 days was the most efficient for induction of tetraploids, yielding 23.5% of tetraploids among all the regenerated shoots. Chimeras were observed in almost all the treatments. However, the ratio of tetraploid to diploid cells in a chimeric plant was usually low. In comparison with diploid plants, tetraploid plants in vitro had larger stomata and thicker roots with more root branches, and had prominently shorter inflorescence stalk when mature.

  7. Agaricus bisporus compost improves the potential of Salix purpurea × viminalis hybrid for copper accumulation.

    Science.gov (United States)

    Magdziak, Z; Mleczek, M; Gąsecka, M; Drzewiecka, K; Kaczmarek, Z; Siwulski, M; Goliński, P

    2016-08-02

    The aim of the study was to determine the ability of spent mushroom compost (SMC) from the production of Agaricus bisporus (A. bisporus) to stimulate the growth and efficiency of copper (Cu) accumulation by Salix purpurea × viminalis hybrid. Roots, shoots and leaves were analysed in terms of total Cu content and selected biometric parameters. Due to the absence of information regarding the physiological response of the studied plant, low molecular weight organic acids (LMWOAs), phenolic compounds and salicylic acid (SA) contents were investigated. The obtained results clearly demonstrate the effectiveness (usefulness) of SMC in promoting the growth and stimulation of Cu accumulation by the studied Salix taxon. The highest Cu content in roots and shoots was found at the 10% SMC addition (507±22 and 380±11 mg kg(-1) DW, respectively), while there was a reduction of the content in leaves and young shoots (109±8 and 124±7 mg kg(-1) DW, respectively). In terms of physiological response, lowered secretion of LMWOAs, biosynthesis of phenolic compounds and SA, as well as accumulation of soluble sugars in Salix leaves was observed with SMC addition. Simultaneously, an elevation of the total phenolic content in leaves of plants cultivated with SMC was observed, considered as antioxidant biomolecules.

  8. Immune enhancing effects of Echinacea purpurea root extract by reducing regulatory T cell number and function.

    Science.gov (United States)

    Kim, Hyung-Ran; Oh, Sei-Kwan; Lim, Woosung; Lee, Hyeon Kook; Moon, Byung-In; Seoh, Ju-Young

    2014-04-01

    Echinacea purpurea preparations (EPs) have been traditionally used for the treatment of various infections and also for wound healing. Accumulating evidence suggests their immunostimulatory effects. Regulatory T cells (Tregs) are known to play a key role in immune regulation in vivo. However, there have been no reports so far on the effects of EP on the frequency or function of Tregs in vivo. Therefore, in the present study, we investigated the quantitative and functional changes in Tregs by in vivo administration with EP. The frequencies of CD4+FoxP3+ and CD4+CD25+ Tregs in the spleens of BALB/c mice administered with EP for 3 weeks were investigated by flow cytometry. The suppressive function of CD4CD25+ Tregs in association with the proliferative activity of CD4+CD25 effector T cells (Teffs) and the feeder function of CD4 antigen-presenting cells (APCs) were analyzed by carboxyfluorescein succinimidyl ester-dilution assay. The results showed a lowered frequency of CD4+FoxP3+ and CD4+CD25+ Tregs and attenuated suppressive function of CD4+CD25+ Tregs, while the feeder function of APCs was enhanced in the EP-administered mice. On the other hand, the proliferative activity of Teffs was not significantly different in the EP-administered mice. The results suggest that decreased number and function of Tregs, in association with the enhanced feeder function of APCs, may contribute to the enhancement of immune function by EP.

  9. Effect of Echinacea purpurea L. on oxidative status and meat quality in Arbor Acres broilers.

    Science.gov (United States)

    Lee, Tzu Tai; Ciou, Jhih Ying; Chen, Chung Li; Yu, Bi

    2013-01-15

    Echinacea purpurea L. (EP) is a popular herbal antioxidant and immunomodulator. The present study was conducted to evaluate the effects of EP on meat quality and oxidative status in broilers. Two hundred and fifty (1-day-old) male broilers (Arbor Acres) were randomly allocated to five groups including the control (corn-soybean meal diet) and 0.1, 0.5, 1.0 and 2.0% EP powder groups, with two replicates per treatment group. The results indicated that the addition of 0.5% and 1.0% EP significantly increased water-holding capacity and decreased storage loss of breast and thigh fillets at 35 days old. For fillet colour, L* (lightness) values were lower, and a* (redness) and b* (yellowness) values were higher with EP supplementation. Lower crude fat contents were observed in EP groups in comparison with control at 35 days of age in breast and thigh fillets, respectively. Production of malondialdehyde was slightly reduced in serum of EP supplemented birds compared to the control group. Results for Trolox equivalent antioxidant capacity, catalase and superoxide dismutase were significantly higher for the 0.5, 1.0 and 2.0% EP supplemental groups than control group in serum. Liver and spleen tissues results showed that the antioxidative enzymes activities were higher with EP powder at 35 days of age. Dried EP can be used as a feed additive to improve the meat quality and oxidative status in Arbor Acres broilers. Copyright © 2012 Society of Chemical Industry.

  10. Synergetic effects of oral administration of levamisole and Echinacea purpurea on immune response in Wistar rat.

    Science.gov (United States)

    Sadigh-Eteghad, Saeed; khayat-Nuri, Hadi; Abadi, Narges; Ghavami, Siavash; Golabi, Mostafa; Shanebandi, Dariush

    2011-08-01

    This research investigated the effects of levamisole and Echinacea purpurea (EP), separately and together on the immune response of the rat as a laboratory model. In this experiment, 40 male Wistar rats were obtained and divided into four groups (n=10). These groups received normal saline (10 mg/kg), EP (500 mg/kg), levamisole (2 mg/kg) and EP (500 mg/kg) with levamisole (2 mg/kg) as oral gavages every day for a period of 4 weeks, respectively. After obtaining blood samples (at the end of each week), haematocrit (HCT), differential and total white blood cell (WBC) counts, phagocyte activity (number), total protein, albumin and globulins levels of samples were obtained. The results of the study showed that the gamma globulin level, WBC, neutrophil and monocyte counts and phagocyte activity increased significantly in comparison with normal saline group during the study. According to the results, each of the mentioned agents had a stimulant effect on the immune system separately and together on rats. In the group that received EP and levamisole simultaneously, these effects were synergistically increased. These compounds, by increasing the mentioned factors, will probably affect the immune system. Crown Copyright © 2010. Published by Elsevier India Pvt Ltd. All rights reserved.

  11. Antibiotic resistance differentiates Echinacea purpurea endophytic bacterial communities with respect to plant organs.

    Science.gov (United States)

    Mengoni, Alessio; Maida, Isabel; Chiellini, Carolina; Emiliani, Giovanni; Mocali, Stefano; Fabiani, Arturo; Fondi, Marco; Firenzuoli, Fabio; Fani, Renato

    2014-10-01

    Recent findings have shown that antibiotic resistance is widespread in multiple environments and multicellular organisms, as plants, harboring rich and complex bacterial communities, could be hot spot for emergence of antibiotic resistances as a response to bioactive molecules production by members of the same community. Here, we investigated a panel of 137 bacterial isolates present in different organs of the medicinal plant Echinacea purpurea, aiming to evaluate if different plant organs harbor strains with different antibiotic resistance profiles, implying then the presence of different biological interactions in the communities inhabiting different plant organs. Data obtained showed a large antibiotic resistance variability among strains, which was strongly related to the different plant organs (26% of total variance, P < 0.0001). Interestingly this uneven antibiotic resistance pattern was present also when a single genus (Pseudomonas), ubiquitous in all organs, was analyzed and no correlation of antibiotic resistance pattern with genomic relatedness among strains was found. In conclusion, we speculate that antibiotic resistance patterns are tightly linked to the type of plant organ under investigation, suggesting the presence of differential forms of biological interaction in stem/leaves, roots and rhizosphere. Copyright © 2014 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  12. Antagonistic interactions between endophytic cultivable bacterial communities isolated from the medicinal plant Echinacea purpurea.

    Science.gov (United States)

    Maida, Isabel; Chiellini, Carolina; Mengoni, Alessio; Bosi, Emanuele; Firenzuoli, Fabio; Fondi, Marco; Fani, Renato

    2016-09-01

    In this work we have studied the antagonistic interactions existing among cultivable bacteria isolated from three ecological niches (rhizospheric soil, roots and stem/leaves) of the traditional natural medicinal plant Echinacea purpurea. The three compartments harboured different taxonomic assemblages of strains, which were previously reported to display different antibiotic resistance patterns, suggesting the presence of differential selective pressure due to antagonistic molecules in the three compartments. Antagonistic interactions were assayed by the cross-streak method and interpreted using a network-based analysis. In particular 'within-niche inhibition' and 'cross-niche inhibition' were evaluated among isolates associated with each compartment as well as between isolates retrieved from the three different compartments respectively. Data obtained indicated that bacteria isolated from the stem/leaves compartment were much more sensitive to the antagonistic activity than bacteria from roots and rhizospheric soil. Moreover, both the taxonomical position and the ecological niche might influence the antagonistic ability/sensitivity of different strains. Antagonism could play a significant role in contributing to the differentiation and structuring of plant-associated bacterial communities. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  13. Induction of tetraploids from petiole explants through colchicine treatments in Echinacea purpurea L.

    Science.gov (United States)

    Nilanthi, Dahanayake; Chen, Xiao-Lu; Zhao, Fu-Cheng; Yang, Yue-Sheng; Wu, Hong

    2009-01-01

    Petiole explants were obtained from in vitro grown diploid (2x = 22) Echinacea purpurea plantlets. Shoots were regenerated by culturing the explants on MS basal medium containing 0.3 mg/L benzyladenine (BA), 0.01 mg/L naphthaleneacetic acid (NAA) and four concentrations (30, 60, 120, and 240 mg/L) of colchicine for 30 days, or 120 mg/L of colchicine for various durations (7, 14, 21, and 28 days). The regenerated shoots were induced to root on MS basal medium with 0.01 mg/L NAA, and then the root-tips of the regenerated shoots were sampled for count of chromosome number. It was found that a treatment duration of >7 days was necessary for induction of tetraploid (4x = 44) shoots, and treatment with 120 mg/L colchicine for 28 days was the most efficient for induction of tetraploids, yielding 23.5% of tetraploids among all the regenerated shoots. Chimeras were observed in almost all the treatments. However, the ratio of tetraploid to diploid cells in a chimeric plant was usually low. In comparison with diploid plants, tetraploid plants in vitro had larger stomata and thicker roots with more root branches, and had prominently shorter inflorescence stalk when mature.

  14. Spasmolytic, bronchodilator and vasorelaxant activity of methanolic extract of Tephrosia purpurea.

    Science.gov (United States)

    Janbaz, Khalid Hussain; Jan, Asma; Qadir, M Imran; Gilani, Anwarul Hassan

    2013-01-01

    The methanolic extract of the whole plant of Tephrosia pupurea, Linn. was subjected to find out its possible therapeutic utility to validate its folkloric use in native systems of medicine. The extract on application to spontaneous contractions in isolated rabbit jejunum preparations exerted a concentration dependent (0.003-3.0 mg/mL) relaxant effect. The extract also caused concentration dependent relaxation of K+(80 mM)-induced spastic contractions. These findings were further supported by the observations that the extract caused a concentration dependent right ward shift of the Ca2+ response curves in manner similar to that of verapamil. The extract exhibited a relaxant effect on carbachol and high K+ (80 mM)-induced contractions of isolated rabbit tracheal preparations in a manner similar to verapamil. The observed non-specific bronchodilator response is possibly mediated through Ca2+ channel blockade. Moreover, the extract also exhibited a dose dependent relaxant effect on phenylephrine (1 microM) and K+(80 mM)-induced contractions in a manner similar to verapamil. On the basis of the above-mentioned findings, it can be concluded that the use of Tephrosia purpurea, in gastrointestinal spasm, asthma and hypertension is likely to be mediated through calcium channel blockage.

  15. The Tradescantia pallida var. purpurea active bioassay for water monitoring: evaluating and comparing methodological conditions

    Directory of Open Access Journals (Sweden)

    Mara Betânia Brizola Cassanego

    2014-07-01

    Full Text Available Tradescantia pallida var. purpurea cuttings with flower buds are utilized in bioassays to diagnose genotoxic effects of water. The literature describes different substances used to adapt and recover the cuttings before and after exposure to water samples and also describes the effects of different exposure times. This study evaluated and compared the micronuclei (MCN frequencies in T. pallida when cuttings with flower buds were submitted to different methodological conditions. The bioassay was then applied bimonthly during seven months to assess the genotoxic potential of a site located on the Sinos River in Campo Bom, Rio Grande do Sul, Brazil. Micronuclei frequencies in buds of cuttings adapted and recovered in distilled water and in Hoagland solution were 3.0 and 2.9, respectively, for cuttings exposed to river water, and 1.19 and 1.23 in controls. No significant differences among MCN frequencies were observed when cuttings were exposed for 8, 24 or 32 hours to river water (from 3.07 to 4.73 and in controls (from 1.13 to 2.00 in all samplings during a year. Adaptation and recovery of cuttings in distilled water or Hoagland solution and exposure for different times did not influence the response of T. pallida, indicating that all the conditions tested are viable for biomonitoring of water genotoxicity. Water samples from the Sinos River presented genotoxicity during the period monitored, evidenced by the MCN frequencies recorded which were significantly higher than the frequencies of the controls.

  16. A spatially explicit analysis of seedling recruitment in the terrestrial orchid Orchis purpurea.

    Science.gov (United States)

    Jacquemyn, Hans; Brys, Rein; Vandepitte, Katrien; Honnay, Olivier; Roldán-Ruiz, Isabel; Wiegand, Thorsten

    2007-01-01

    Seed dispersal and the subsequent recruitment of new individuals into a population are important processes affecting the population dynamics, genetic diversity and spatial genetic structure of plant populations. Spatial patterns of seedling recruitment were investigated in two populations of the terrestrial orchid Orchis purpurea using both univariate and bivariate point pattern analysis, parentage analysis and seed germination experiments. Both adults and recruits showed a clustered spatial distribution with cluster radii of c. 4-5 m. The parentage analysis resulted in offspring-dispersal distances that were slightly larger than distances obtained from the point pattern analyses. The suitability of microsites for germination differed among sites, with strong constraints in one site and almost no constraints in the other. These results provide a clear and coherent picture of recruitment patterns in a tuberous, perennial orchid. Seed dispersal is limited to a few metres from the mother plant, whereas the availability of suitable germination conditions may vary strongly from one site to the next. Because of a time lag of 3-4 yr between seed dispersal and actual recruitment, and irregular flowering and fruiting patterns of adult plants, interpretation of recruitment patterns using point patterns analyses ideally should take into account the demographic properties of orchid populations.

  17. Use of ethylenediurea (EDU) to ameliorate ozone effects on purple coneflower (Echinacea purpurea).

    Science.gov (United States)

    Szantoi, Zoltan; Chappelka, Arthur H; Muntifering, Russell B; Somers, Greg L

    2007-11-01

    Purple coneflower plants (Echinacea purpurea) were placed into open-top chambers (OTCs) for 6 and 12 weeks in 2003 and 2004, respectively, and exposed to charcoal-filtered air (CF) or twice-ambient (2x) ozone (O3) in 2003, and to CF, 2x or non-filtered (NF), ambient air in 2004. Plants were treated with ethylenediurea (EDU) weekly as a foliar spray. Foliar symptoms were observed in >95% of the plants in 2x-treated OTCs in both years. Above-ground biomass was not affected by 2x treatments in 2003, but root and total-plant biomass decreased in 2004. As a result of higher concentrations of select cell wall constituents (% ADF, NDF and lignin) nutritive quality was lower for plants exposed to 2x-O3 in 2003 and 2004 (26% and 17%, respectively). Significant EDU x O3 interactions for concentrations of cell wall constituents in 2003 indicated that EDU ameliorated O3 effects on nutritive quality. Interactions observed in 2004 were inconsistent.

  18. Global existence of solutions and uniform persistence of a diffusive predator-prey model with prey-taxis

    Science.gov (United States)

    Wu, Sainan; Shi, Junping; Wu, Boying

    2016-04-01

    This paper proves the global existence and boundedness of solutions to a general reaction-diffusion predator-prey system with prey-taxis defined on a smooth bounded domain with no-flux boundary condition. The result holds for domains in arbitrary spatial dimension and small prey-taxis sensitivity coefficient. This paper also proves the existence of a global attractor and the uniform persistence of the system under some additional conditions. Applications to models from ecology and chemotaxis are discussed.

  19. Linking biomechanics and ecology through predator-prey interactions: flight performance of dragonflies and their prey.

    Science.gov (United States)

    Combes, S A; Rundle, D E; Iwasaki, J M; Crall, J D

    2012-03-15

    Aerial predation is a highly complex, three-dimensional flight behavior that affects the individual fitness and population dynamics of both predator and prey. Most studies of predation adopt either an ecological approach in which capture or survival rates are quantified, or a biomechanical approach in which the physical interaction is studied in detail. In the present study, we show that combining these two approaches provides insight into the interaction between hunting dragonflies (Libellula cyanea) and their prey (Drosophila melanogaster) that neither type of study can provide on its own. We performed >2500 predation trials on nine dragonflies housed in an outdoor artificial habitat to identify sources of variability in capture success, and analyzed simultaneous predator-prey flight kinematics from 50 high-speed videos. The ecological approach revealed that capture success is affected by light intensity in some individuals but that prey density explains most of the variability in success rate. The biomechanical approach revealed that fruit flies rarely respond to approaching dragonflies with evasive maneuvers, and are rarely successful when they do. However, flies perform random turns during flight, whose characteristics differ between individuals, and these routine, erratic turns are responsible for more failed predation attempts than evasive maneuvers. By combining the two approaches, we were able to determine that the flies pursued by dragonflies when prey density is low fly more erratically, and that dragonflies are less successful at capturing them. This highlights the importance of considering the behavior of both participants, as well as their biomechanics and ecology, in developing a more integrative understanding of organismal interactions.

  20. Insect prey foraging strategies in Callicebus oenanthe in northern Peru.

    Science.gov (United States)

    Deluycker, Anneke M

    2012-05-01

    Titi monkeys (genus Callicebus) are small-bodied platyrrhines that supplement their predominantly frugivorous diet with variable amounts of leaves, seeds, and/or arthropod prey. Notable interspecific variation in the amount of insect prey in the diet has been observed in Callicebus, ranging from 0% to 20%. In this study, I investigate the degree and type of prey foraging in a little-known species, Callicebus oenanthe inhabiting a fragmented, secondary forest on the foothills of the Andes in northern Peru. I present data on prey type, prey search and capture techniques, substrate/vegetation use, foraging height, prey capture efficiency, and seasonal variation of insect prey foraging in one group of C. oenanthe observed from January to August 2005. Insect prey accounted for 22% of the diet, the highest amount reported for any Callicebus species to date, and insects from at least six different orders were included. C. oenanthe was mainly an investigative forager of hidden prey, manipulating easy-to-open substrates such as rolled up leaves, and hunted ant swarms and larger insects opportunistically. Insect foraging was predominant during the dry season (26%) and decreased during the wet season (13%). The study group foraged mostly in the understory (2-6 m) within vine-laden shrubs and trees, which may conform to an anti-predator strategy of crypticity. Overall the group had an 83% insect capture success rate. These data suggest that insect prey is an important part of the diet of C. oenanthe and may be especially notable during periods of resource scarcity. This study adds to the knowledge concerning insect prey foraging in Callicebus, which can have an important role in defining ecological strategies in the selection of secondary protein food resources within a given ecosystem.

  1. In-vitro activity of saponins of bauhinia purpurea, madhuca longifolia, celastrus paniculatus and semecarpus anacardium on selected oral pathogens.

    Science.gov (United States)

    Jyothi, K S; Seshagiri, M

    2012-01-01

    Dental caries, periodontitis and other mucosal diseases are caused by a complex community of microorganisms. This study aimed to investigate the antimicrobial properties of saponins of four important oil yielding medicinal plant extracts on selected oral pathogens that are involved in such diseases. Saponins were extracted from Bauhinia purpurea, Madhuca longifolia, Celastrus paniculatus and Semecarpus anacardium and purified. Antimicrobial properties of these saponins against Streptococcus mutans, Streptococcus mitis, Streptococcus salivarius, Staphylococcus aureus and Lactobacillus acidophilus were determined using well diffusion method. The minimum inhibitory concentration (MIC) was determined as the lowest concentration of saponins inhibiting bacterial growth after 14 h of incubation at 37°C. The bactericidal activity was evaluated using the viable cell count method. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of Madhuca longifolia saponin on Streptococcus mutans MTCC 890, Streptococcus mitis and Staphylococcus aureus was 18.3 ± 0.15/34.4 ± 0.24 μg/ml, 19.0 ± 0.05/32.2 ± 0.0 μg/ml and 21.2 ± 0.35/39.0 ± 0.30 μg/ml, respectively and Bauhinia purpurea saponin on Streptococcus mutans MTCC 890, Staphylococcus aureus and Lactobacillus acidophilus was 26.4 ± 0.20/43.0 ± 0.40 μg/ml, 29.0 ± 0.30/39.6 ± 0.12 μg/ml and 20.2 ± 0.05/36.8 ± 0.23 μg/ml, respectively. The strong antimicrobial activity of Madhuca longifolia and Bauhinia purpurea may be due to the presence of complex triterpenoid saponins, oleanane type triterpenoid glycosides or atypical pentacyclic triterpenoid saponin. Hence, these extracted saponins may be used in food and oral products to prevent and control oral diseases.

  2. Molecular Phylogeny, Diversity, and Bioprospecting of Endophytic Fungi Associated with wild Ethnomedicinal North American Plant Echinacea purpurea (Asteraceae).

    Science.gov (United States)

    Carvalho, Camila R; Wedge, David E; Cantrell, Charles L; Silva-Hughes, Alice F; Pan, Zhiqiang; Moraes, Rita M; Madoxx, Victor L; Rosa, Luiz H

    2016-07-01

    The endophytic fungal community associated with the ethnomedicinal plant Echinacea purpurea was investigated as well as its potential for providing antifungal compounds against plant pathogenic fungi. A total of 233 endophytic fungal isolates were obtained and classified into 42 different taxa of 16 genera, of which Alternaria alternata, Colletotrichum dematium, and Stagonosporopsis sp. 2 are the most frequent colonizers. The extracts of 29 endophytic fungi displayed activities against important phytopathogenic fungi. Eight antifungal extracts were selected for chemical analysis. Forty fatty acids were identified by gas chromatography-flame-ionization detection (GC-FID) analysis. The compounds (-)-5-methylmellein and (-)-(3R)-8-hydroxy-6-methoxy-3,5-dimethyl-3,4-dihydroisocoumarin were isolated from Biscogniauxia mediterraneaEPU38CA crude extract. (-)-5-Methylmellein showed weak activity against Phomopsis obscurans, P. viticola, and Fusarium oxysporum, and caused growth stimulation of C. fragariae, C. acutatum, C. gloeosporioides, and Botrytis cinerea. (-)-(3R)-8-Hydroxy-6-methoxy-3,5-dimethyl-3,4-dihydroisocoumarin appeared slightly more active in the microtiter environment than 5-methylmellein. Our results indicate that E. purpurea lives symbiotically with different endophytic fungi, which are able to produce bioactive fatty acids and aromatic compounds active against important phytopathogenic fungi. The detection of the different fatty acids and aromatic compounds produced by the endophytic community associated with wild E. purpurea suggests that it may have intrinsic mutualistic resistance against phytopathogen attacks in its natural environment.

  3. Cytotoxic effects of Echinacea purpurea flower extracts and cichoric acid on human colon cancer cells through induction of apoptosis.

    Science.gov (United States)

    Tsai, Yu-Ling; Chiu, Chien-Chih; Yi-Fu Chen, Jeff; Chan, Kung-Chi; Lin, Sheng-Dun

    2012-10-11

    Echinacea is a top-selling herbal supplement that acts as immunostimulant. It has been used to treat common cold, coughs, bronchitis and upper respiratory infections. It is also a popular product used in anticancer therapy. The cytotoxic effects of Echinacea on cancer cells are still not clear. The aims of this study were to provide a preliminary validation of the effects of 50% aqueous ethanol extract of Echinacea purpurea flowers and its major compound, cichoric acid, on human colon cancer cells Caco-2 and HCT-116. The cytotoxic effects of Echinace flower extracts and cichoric acid on cell viability, telomerase activity, DNA fragmentation, β-catenin, caspase-9, and cleavage of poly-ADP-ribose polymerase (PARP) of human colon cancer cell were examined. The results showed a significant inhibition of proliferation in E. purpurea flower extract and cichoric acid in a dose- and time-dependent manner. Cichoric acid treatment decreased telomerase activity in HCT-116 cells. Moreover, cichoric acid effectively induced apoptosis in colon cancer cells, which were characterized by DNA fragmentation, activation of caspase-9, cleavage of PARP and downregulation of β-catenin. Our data indicate that cichoric acid has a strong growth-inhibitory effect against colon cancer cells, presumably resulting from the reduced telomerase activity and the induction of apoptosis. The exact mechanism of action should still be determined in future studies. Overall, the effects of 50% aqueous ethanol extract of E. purpurea flowers and cichoric acid may have provided in vitro evidence for the use as chemotherapeutic agents. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  4. Studies on phytochemical, antioxidant, anti-inflammatory, hypoglycaemic and antiproliferative activities of Echinacea purpurea and Echinacea angustifolia extracts.

    Science.gov (United States)

    Aarland, Rayn Clarenc; Bañuelos-Hernández, Angel Ernesto; Fragoso-Serrano, Mabel; Sierra-Palacios, Edgar Del Carmen; Díaz de León-Sánchez, Fernando; Pérez-Flores, Laura Josefina; Rivera-Cabrera, Fernando; Mendoza-Espinoza, José Alberto

    2017-12-01

    Echinacea (Asteraceae) is used because of its pharmacological properties. However, there are few studies that integrate phytochemical analyses with pharmacological effects. Evaluate the chemical profile and biological activity of hydroalcoholic Echinacea extracts. Density, dry matter, phenols (Folin-Ciocalteu method), flavonoids (AlCl3 method), alkylamides (GC-MS analysis), antioxidant capacity (DPPH and ABTS methods), antiproliferative effect (SRB assay), anti-inflammatory effect (paw oedema assay, 11 days/Wistar rats; 0.4 mL/kg) and hypoglycaemic effect (33 days/Wistar rats; 0.4 mL/kg) were determined in three Echinacea extracts which were labelled as A, B and C (A, roots of Echinacea purpurea L. Moench; B, roots, leaves, flowers and seeds of Echinacea purpurea; C, aerial parts and roots of Echinacea purpurea and roots of Echinacea angustifolia DC). Extract C showed higher density (0.97 g/mL), dry matter (0.23 g/mL), phenols (137.5 ± 2.3 mEAG/mL), flavonoids (0.62 ± 0.02 mEQ/mL), and caffeic acid (0.048 mg/L) compared to A and B. A, B presented 11 alkylamides, whereas C presented those 11 and three more. B decreased the oedema (40%) on day 2 similar to indomethacin. A and C showed hypoglycaemic activity similar to glibenclamide. Antiproliferative effect was only detected for C (IC50 270 μg/mL; 8171 μg/mL; 9338 μg/mL in HeLa, MCF-7, HCT-15, respectively). The difference in the chemical and pharmacological properties among extracts highlights the need to consider strategies and policies for standardization of commercial herbal extracts in order to guarantee the safety and identity of this type of products.

  5. Radioprotection effect on irradiation mice of haemopoietic cell of echinacea purpurea(north American herb) by the celiac medication

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    Saito, Kiyoto; Gu, Yeunhwa; Ukawa, Yuuichi; Park, Sangrea; Trai, Kaoru; Tanaka, Kenichirou; Tajima, Masayuki; Hasegawa, Takeo; Suzuki, Ikukatsu [Suauka Univ. of Medical Science, Suzuka (Japan); Mishima, Satoshi [Api Co., LTD., Kifu (Japan)

    2002-07-01

    The medicine that suspension made phosphoric acid saline make the dryness leaf powder of Echinacea purpurea which is typical north American herb in medical herb with the multiple seeds muddy, in the ICR male mouse (age of five weeks). It period in three times a week, eight weeks, and Celiac Medication was given. (360mg/kg/mouse). 2Gy irradiated it by the X-ray irradiation device (200kV, 0.35Gy/min) for the Echinacea purpurea medication the third week. Collecting blood was done in the sutra time target from the day before X-ray irradiation, and a change in the corpuscle number (the number of the leukocyte, the number of the lymphocyte, the number of the granulocytes, the number of monocyte) was observed. The number of the leukocytes of the non-medication control group faced, and increase in the number of the leukocytes in the medication group wasn't recognized with the thing before the X-ray irradiation as a result. It faced though the number of the leukocytes decreased remarkably due to the radiation irradiation in the non-medication control group, and the decrease was controlled as for the medication group. The recovery of the number of the leukocytes of the medication group in the group after the X-ray irradiation showed a tendency of becoming early in comparison with the non-medication control group. As for the number of the lymphocyte except for the leukocyte, the number of the granulocyte, the number of monocyte as well, it could get the same result as the number of the leukocytes. Than the above result, Echinacea purpurea toward the mice blood cell. Effect on radiation protection along with effect on repression of a blood number decrease due to the irradiation manufactured by was suggested.

  6. Effects of chemically characterized fractions from aerial parts of Echinacea purpurea and E. angustifolia on myelopoiesis in rats.

    Science.gov (United States)

    Ramasahayam, Sindhura; Baraka, Hany N; Abdel Bar, Fatma M; Abuasal, Bilal S; Widrlechner, Mark P; Sayed, Khalid A El; Meyer, Sharon A

    2011-11-01

    Echinacea species are used for beneficial effects on immune function, and various prevalent phytochemicals have immunomodulatory effects. Using a commercial E. purpurea (L.) Moench product, we have evaluated the myelopoietic effect on bone marrow of rats treated with various extracts and correlated this with their chemical class composition. Granulocyte/macrophage-colony forming cells (GM-CFCs) from femurs of female Sprague-Dawley rats were assessed at 24 h after 7 daily oral treatments. A 75% ethanolic extract at 50 mg dried weight (derived from 227 mg aerial parts) per kg body weight increased GM-CFCs by 70% but at 100 mg/kg was without effect. Ethanolic extracts from aerial parts of E. angustifolia DC. var. angustifolia and E. purpurea from the USDA North Central Regional Plant Introduction Station increased GM-CFCs by 3- and 2-fold, respectively, at 200 mg/kg (~1400 mg/kg plant material). Extract from another USDA E. angustifolia was inactive. Proton and APT NMR, MS, and TLC indicated alkylamides and caffeic-acid derivatives (CADs) present in ethanolic extracts of both the commercial and USDA-derived material. Cichoric and caftaric acids were prominent in both E. purpurea ethanolic extracts but absent in E. angustifolia. Aqueous extract of the commercial material exhibited polysaccharide and CAD signatures and was without effect on GM-CFCs. A methanol-CHCl3 fraction of commercial source, also inactive, was almost exclusively 1:4 nonanoic: decanoic acids, which were also abundant in commercial ethanolic extract but absent from USDA material. In conclusion, we have demonstrated an ethanolextractable myelostimulatory activity in Echinacea aerial parts that, when obtained from commercial herbal supplements, may be antagonized by medium-chain fatty acids presumably derived from a non-plant additive. © Georg Thieme Verlag KG Stuttgart · New York.

  7. In-Vitro Activity of Saponins of Bauhinia Purpurea Madhuca Longifolia Celastrus Paniculatus and Semecarpus Anacardium on Selected Oral Pathogens

    Directory of Open Access Journals (Sweden)

    K. S. Jyothi

    2012-01-01

    Full Text Available Objective: Dental caries, periodontitis and other mucosal diseases are caused by a complex community of microorganisms. This study aimed to investigate the antimicrobial properties of saponins of four important oil yielding medicinal plant extracts on selected oral pathogens that are involved in such diseases.Materials and Methods: Saponins were extracted from Bauhinia purpurea, Madhuca longifolia, Celastrus paniculatus and Semecarpus anacardium and purified. Antimicrobial properties of these saponins against Streptococcus mutans, Streptococcus mitis, Streptococcus salivarius, Staphylococcus aureus and Lactobacillus acidophilus were determined using well diffusion method. The minimum inhibitory concentration (MIC was determined as the lowest concentration of saponins inhibiting bacterial growth after 14 h of incubation at 37°C. The bactericidal activity was evaluated using the viable cell count method.Results: The minimum inhibitory concentration (MIC and minimum bactericidal concentration (MBC of Madhuca longifolia saponin on Streptococcus mutans MTCC 890, Streptococcus mitis and Staphylococcus aureus was 18.3 ± 0.15/34.4 ± 0.24 µg/ml, 19.0 ± 0.05/32.2 ± 0.0 µg/ml and 21.2 ± 0.35/39.0 ± 0.30 µg/ml, respectively and Bauhinia purpurea saponin on Streptococcus mutans MTCC 890, Staphylococcus aureus and Lactobacillus acidophilus was 26.4 ± 0.20/43.0 ± 0.40 µg/ml, 29.0 ± 0.30/39.6 ± 0.12 µg/ml and 20.2 ± 0.05/36.8 ± 0.23 µg/ml, respectively.Conclusion: The strong antimicrobial activity of Madhuca longifolia and Bauhinia purpurea may be due to the presence of complex triterpenoid saponins, oleanane type triterpenoid glycosides or atypical pentacyclic triterpenoid saponin. Hence, these extracted saponins may be used in food and oral products to prevent and control oral diseases.

  8. Sistemas de producción de Spondias purpurea (Anacardiaceae en el centro-occidente de México

    Directory of Open Access Journals (Sweden)

    Blanca C Ramírez Hernández

    2008-06-01

    Full Text Available Describimos las características de los agroecosistemas y rasgos morfológicos, físicos y químicos relacionados con la calidad de los frutos de la guayaba, Spondias purpurea L., que se producen en poblaciones silvestres y cultivadas en el centro-occidente de México. Spondias purpurea se desarrolla en suelos rocosos, poco profundos e infértiles, poco aptos para la agricultura tradicional. En los frutos se registró el peso, longitud axial y radial, pH, sólidos solubles totales (SST, azúcares reductores, proteínas y contenido de minerales. El peso promedio de frutos en las variedades cultivadas (20 g resultó superior al de las silvestres (16 g. Las variedades cultivadas registraron en promedio los valores más altos de pH, SST, azúcares reductores y contenido de proteínas (3.3, 12.15º Brix, 0.38 g/100 g y 1.18 g/100 g, respectivamente que las silvestres (3.0, 8.31º Brix, 0.24 g/100 g y 0.14 g/100 g, respectivamente. La productividad de la especie es aceptable (de 0.15 ton ha-1 a 5.0 ton ha-1 dado que requiere de un mínimo de manejo agronómico. Esta especie tiene un contenido nutrimental comparable al de las especies frutales más importantes; además, produce frutos frescos durante los meses secos de la primavera por lo que S. purpurea es fuente de agua y alimento para la fauna silvestre y doméstica. Estas características resaltan su importancia agronómica y ecológica para los ambientes tropicales y subtropicales en donde puede ser utilizada en programas de reforestación por su capacidad para desarrollarse en suelos rocosos infértiles, y en agroecosistemas en los que se practica agricultura de subsistencia. De hecho, el cultivo de S. purpurea puede ayudar a convertir suelos marginales en productivos.Production systems of Spondias purpurea (Anacardiaceae in Central West México. Morphological, physical and chemical traits related with fruit quality characteristics of Spondias purpurea L. agroecosystems were studied in Central

  9. Amelioration of cisplatin-induced nephrotoxicity by ethanolic extract of Bauhinia purpurea: An in vivo study in rats

    Directory of Open Access Journals (Sweden)

    Md Azmat Rana

    2016-01-01

    Full Text Available Our objective is to study the nephroprotective activity and antioxidant potential of Bauhinia purpurea unripe pods and bark against cisplatin-induced nephrotoxicity. Healthy adult albino rats of either sex (150-200 g were randomly divided into six groups of six animals each Group I (vehicle control and Group II (negative control. Group III (BBE200 and Group IV (BBE400 were administered the ethanolic extract of Bauhinia purpurea bark in doses of 200 and 400 mg/kg/day p.o., respectively, and Group V (BPE200 and Group VI (BPE400 were administered the ethanolic extract of Bauhinia purpurea unripe pods at doses of 200 and 400 mg/kg/day p.o., respectively. All the treatments were given for nine days. Cisplatin in a single dose of 6 mg/kg i.p. was given on the 4 th day to all groups, except the vehicle control group. On the 10 th day, blood and urine were collected for biochemical tests and the rats were sacrificed. The kidney was removed for histology and lipid peroxidation-antioxidant test. Cisplatin caused nephrotoxicity as evidenced by elevated blood urea, serum creatinine and urine glucose, and there was decreased creatinine clearance in Group II as compared with Group I. Administration of BBE and BPE at doses of 200 and 400 mg/kg in Group III and Group VI caused a dose-dependant reduction in the rise of blood urea, serum creatinine and urine glucose, and there was a dosedependant increase in creatinine clearance compared with Group II. There was increased catalase and glutathione and decreased malondialdehyde levels in Group II, while BBE 400 (Group IV and BPE 400 (Group VI treatments significantly reversed the changes toward normal values. Histological examination of the kidney revealed protection in Group IV and Group VI compared with Group II. The ethanolic extract of Bauhinia purpurea unripe pods and bark has a nephroprotective activity against cisplatin-induced nephrotoxicity in rats.

  10. HPLC method validated for the simultaneous analysis of cichoric acid and alkamides in Echinacea purpurea plants and products

    DEFF Research Database (Denmark)

    Mølgaard, Per; Johnsen, Søren; Christensen, Peter

    2003-01-01

    A reversed-phase high-performance liquid chromatography (HPLC) method has been developed to determine caffeic acid derivatives, for example, cichoric acid, and alkamides in plant parts and herbal products of Echinacea purpurea. The method consists of an extraction procedure whereby the hydrophilic...... phenolics as well as the lipophilic alkamides are released from the samples, followed by the analytical HPLC procedure for quantitative determination of these compounds. The method is the first one validated for the determination of these two groups of compounds in the same procedure. Naringenin has been...

  11. Invasive prey indirectly increase predation on their native competitors.

    Science.gov (United States)

    Castorani, Max C N; Hovel, Kevin A

    2015-07-01

    Ecological theory predicts that invasive prey can interact with native prey directly by competing for shared resources or indirectly by changing the abundance or behavior of shared native predators. However, both the study and management of invasive prey have historically overlooked indirect effects. In southern California estuaries, introduction of the Asian nest mussel Arcuatula senhousia has been linked to profound changes in native bivalve assemblages, but the mechanisms of these interactions remain unclear. We performed three field experiments to assess the mechanisms of competition between Arcuatula and native bivalves, and evaluated the potential for Arcuatula to indirectly mediate native predator-prey dynamics. We found that Arcuatula reduces the diversity, abundance, and size of native bivalve recruits by preemptively exploiting space in surface sediments. When paired with native shallow-dwelling clams (Chione undatella and Laevicardium substriatum), Arcuatula reduces adult survival through overgrowth competition. However, Arcuatula also attracts native predators, causing apparent competition by indirectly increasing predation of native clams, especially for poorly defended species. Therefore, invasive prey can indirectly increase predation rates on native competitors by changing the behavior of shared native predators, but the magnitude of apparent competition strongly depends on the vulnerability of natives to predation. Interestingly, our results indicate that the vulnerability of invasive prey to predation can greatly exacerbate impacts on their native competitors. Our findings suggest that consideration of both direct and indirect effects of invasive prey, as well as native predator-prey relationships, should lead to more effective invasive species management.

  12. Influence of stochastic perturbation on prey-predator systems.

    Science.gov (United States)

    Rudnicki, Ryszard; Pichór, Katarzyna

    2007-03-01

    We analyse the influence of various stochastic perturbations on prey-predator systems. The prey-predator model is described by stochastic versions of a deterministic Lotka-Volterra system. We study long-time behaviour of both trajectories and distributions of the solutions. We indicate the differences between the deterministic and stochastic models.

  13. Evolutionary dynamics of prey exploitation in a metapopulation of predators

    NARCIS (Netherlands)

    Pels, S.H.; de Roos, A.M.; Sabelis, M.W.

    2002-01-01

    In well-mixed populations of predators and prey, natural selection favors predators with high rates of prey consumption and population growth. When spatial structure prevents the populations from being well mixed, such predators may have a selective disadvantage because they do not make full use of

  14. Top predators negate the effect of mesopredators on prey physiology.

    Science.gov (United States)

    Palacios, Maria M; Killen, Shaun S; Nadler, Lauren E; White, James R; McCormick, Mark I

    2016-07-01

    Predation theory and empirical evidence suggest that top predators benefit the survival of resource prey through the suppression of mesopredators. However, whether such behavioural suppression can also affect the physiology of resource prey has yet to be examined. Using a three-tier reef fish food web and intermittent-flow respirometry, our study examined changes in the metabolic rate of resource prey exposed to combinations of mesopredator and top predator cues. Under experimental conditions, the mesopredator (dottyback, Pseudochromis fuscus) continuously foraged and attacked resource prey (juveniles of the damselfish Pomacentrus amboinensis) triggering an increase in prey O2 uptake by 38 ± 12·9% (mean ± SE). The visual stimulus of a top predator (coral trout, Plectropomus leopardus) restricted the foraging activity of the mesopredator, indirectly allowing resource prey to minimize stress and maintain routine O2 uptake. Although not as strong as the effect of the top predator, the sight of a large non-predator species (thicklip wrasse, Hemigymnus melapterus) also reduced the impact of the mesopredator on prey metabolic rate. We conclude that lower trophic-level species can benefit physiologically from the presence of top predators through the behavioural suppression that top predators impose on mesopredators. By minimizing the energy spent on mesopredator avoidance and the associated stress response to mesopredator attacks, prey may be able to invest more energy in foraging and growth, highlighting the importance of the indirect, non-consumptive effects of top predators in marine food webs.

  15. Curvature facilitates prey fixation in predatory insect claws

    NARCIS (Netherlands)

    Petie, R.; Muller, M.

    2007-01-01

    Insects show a large variety in prey capture strategies, with a correspondingly large diversity in predatory adaptations. We studied a specific type of predatory claws, these can for example be found in praying mantis species. The claw is closeable over its entire length and the prey is fixed betwee

  16. EXTINCTION OF A DISCRETE NONLINEAR PREDATOR-PREY SYSTEM

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In this paper, we consider a discrete nonlinear predator-prey model with nonnegative coefficients bounded above and below by positive constants. We show that under some suitable assumptions the predator species is driven to extinction and the prey species x is globally attractive with any positive solution to a discrete Logistic equation.

  17. Unusual predator-prey dynamics under reciprocal phenotypic plasticity.

    Science.gov (United States)

    Mougi, Akihiko

    2012-07-21

    Recent theories and experiments have shown that plasticity, such as an inducible defense or an inducible offense in predator-prey interactions, strongly influences the stability of the population dynamics. However, such plastic adaptation has not been expected to cause unusual dynamics such as antiphase cycles, which occur in experimental predator-prey systems with evolutionary adaptation in the defensive trait of prey. Here I show that antiphase cycles and cryptic cycles (a large population fluctuation in one species with almost no change in the population of the other species) can occur in a predator-prey system when both member species can change their phenotypes through adaptive plasticity (inducible defenses and offenses). I consider a familiar type of predator-prey system in which both species can change their morphology or behavior through phenotypic plasticity. The plasticity, that is, the ability to change between distinct phenotypes, is assumed to occur so as to maximize their fitness. I examined how the reciprocal adaptive plasticity influences the population dynamics. The results show that unusual dynamics such as antiphase population cycles and cryptic cycles can occur when both species show inducible plasticity. The unusual dynamics are particularly likely to occur when the carrying capacity of the prey is small (the density dependence of the prey's growth is strong). The unusual predator-prey dynamics may be induced by phenotypic plasticity as long as the phenotypic change occurs to maximize fitness.

  18. Periodic Solutions of a Discrete Time Predator-Prey System

    Institute of Scientific and Technical Information of China (English)

    Yong-li Song; Mao-an Han

    2006-01-01

    In this paper, we discuss a discrete predator-prey system with a non-monotonic functional response,which models the dynamics of the prey and the predator having non-overlapping generations. By using the coincidence degree theory, sufficient conditions are obtained for the existence of positive periodic solutions.

  19. Stationary Patterns in One-Predator Two-Prey Models

    DEFF Research Database (Denmark)

    Pedersen, Michael; Zhigui, Lin

    1999-01-01

    Weakly-coupled elliptic system decribing models of simple three-species food webs such as the one-predator, two-prey modelis discussed. We show thatthere is no non-constant solution if diffusions or inter-specific competitions are strong, or if the intrinsic growths of the prey are slow...

  20. Stationary Patterns in One-Predator Two-Prey Models

    DEFF Research Database (Denmark)

    Pedersen, Michael; Zhigui, Lin

    1999-01-01

    Weakly-coupled elliptic system decribing models of simple three-species food webs such as the one-predator, two-prey model is discussed. We show that there is no non-constant solution if diffusions or inter-specific competitions are strong, or if the intrinsic growths of the prey are slow...

  1. Integrated Pest Management with Stochastic Birth Rate for Prey Species

    Directory of Open Access Journals (Sweden)

    Olcay eAkman

    2013-08-01

    Full Text Available X. Song and Z. Xiang [5] developed an impulsive differential equations model for a two-prey one-predator model with stage structure for the predator. They demonstrate the conditions on the impulsiveperiod for which a globally asymptotically stable pest-eradication periodic solution exists, as well asconditions on the impulsive period for which the prey species is permanently maintained under aneconomically acceptable threshold. We extend their model by including stage structure for both predatorand prey as well as by adding stochastic elements in the birth rate of the prey. As in [5], we find theconditions under which a globally asymptotically stable pest eradication periodic solution exists. Inaddition, we numerically show the relationship between the stochastically varying birth rate of the preyand the necessary efficacy of the pesticide for which the probability of eradication of the prey speciesis above 90%. This is significant because the model recognizes varying environmental and climaticconditions which affect the resources needed for pest eradication.

  2. Unique coevolutionary dynamics in a predator-prey system.

    Science.gov (United States)

    Mougi, Akihiko; Iwasa, Yoh

    2011-05-21

    In this paper, we study the predator-prey coevolutionary dynamics when a prey's defense and a predator's offense change in an adaptive manner, either by genetic evolution or phenotypic plasticity, or by behavioral choice. Results are: (1) The coevolutionary dynamics are more likely to be stable if the predator adapts faster than the prey. (2) The prey population size can be nearly constant but the predator population can show very large amplitude fluctuations. (3) Both populations may oscillate in antiphase. All of these are not observed when the handling time is short and the prey's density dependence is weak. (4) The population dynamics and the trait dynamics show resonance: the amplitude of the population fluctuation is the largest when the speed of adaptation is intermediate. These results may explain experimental studies with microorganisms.

  3. Modelling the fear effect in predator-prey interactions.

    Science.gov (United States)

    Wang, Xiaoying; Zanette, Liana; Zou, Xingfu

    2016-11-01

    A recent field manipulation on a terrestrial vertebrate showed that the fear of predators alone altered anti-predator defences to such an extent that it greatly reduced the reproduction of prey. Because fear can evidently affect the populations of terrestrial vertebrates, we proposed a predator-prey model incorporating the cost of fear into prey reproduction. Our mathematical analyses show that high levels of fear (or equivalently strong anti-predator responses) can stabilize the predator-prey system by excluding the existence of periodic solutions. However, relatively low levels of fear can induce multiple limit cycles via subcritical Hopf bifurcations, leading to a bi-stability phenomenon. Compared to classic predator-prey models which ignore the cost of fear where Hopf bifurcations are typically supercritical, Hopf bifurcations in our model can be both supercritical and subcritical by choosing different sets of parameters. We conducted numerical simulations to explore the relationships between fear effects and other biologically related parameters (e.g. birth/death rate of adult prey), which further demonstrate the impact that fear can have in predator-prey interactions. For example, we found that under the conditions of a Hopf bifurcation, an increase in the level of fear may alter the direction of Hopf bifurcation from supercritical to subcritical when the birth rate of prey increases accordingly. Our simulations also show that the prey is less sensitive in perceiving predation risk with increasing birth rate of prey or increasing death rate of predators, but demonstrate that animals will mount stronger anti-predator defences as the attack rate of predators increases.

  4. Heuristic Rules Underlying Dragonfly Prey Selection and Interception.

    Science.gov (United States)

    Lin, Huai-Ti; Leonardo, Anthony

    2017-03-28

    Animals use rules to initiate behaviors. Such rules are often described as triggers that determine when behavior begins. However, although less explored, these selection rules are also an opportunity to establish sensorimotor constraints that influence how the behavior ends. These constraints may be particularly significant in influencing success in prey capture. Here we explore this in dragonfly prey interception. We found that in the moments leading up to takeoff, perched dragonflies employ a series of sensorimotor rules that determine the time of takeoff and increase the probability of successful capture. First, the dragonfly makes a head saccade followed by smooth pursuit movements to orient its direction-of-gaze at potential prey. Second, the dragonfly assesses whether the prey's angular size and speed co-vary within a privileged range. Finally, the dragonfly times the moment of its takeoff to a prediction of when the prey will cross the zenith. Each of these processes serves a purpose. The angular size-speed criteria biases interception flights to catchable prey, while the head movements and the predictive takeoff ensure flights begin with the prey visually fixated and directly overhead-the key parameters that underlie interception steering. Prey that do not elicit takeoff generally fail at least one of the criterion, and the loss of prey fixation or overhead positioning during flight is strongly correlated with terminated flights. Thus from an abundance of potential targets, the dragonfly selects a stereotyped set of takeoff conditions based on the prey and body states most likely to end in successful capture.

  5. Prey to predator size ratio influences foraging efficiency of larval Aeshna juncea dragonflies.

    Science.gov (United States)

    Hirvonen, Heikki; Ranta, Esa

    1996-05-01

    We investigated foraging behaviour of larval dragonflies Aeshna juncea in order to examine the significance of prey density and body size in predator-prey dynamics. A. juncea were offered separately three size-classes of Daphnia magna at low and high densities. The data were collected with direct observations of the foraging individuals. We found that large A. juncea larvae could better enhance their intake of prey biomass as prey size and prey density increased than their smaller conspecifics. However, increasing feeding efficiency of both larval instars was constrained by declining attack success and search rate with increasing prey size and density. With small D. magna, in contrast to large A. juncea, small A. juncea increased their searching efficiency as prey density increased keeping D. magna mortality rate at a constant level. In a predator-prey relationship this indicates stabilizing potential and feeding thresholds set by both prey density and prey-predator size ratio. Attack success dropped with prey size and density, but did not change in the course of the foraging bout. For both A. juncea sizes prey handling times increased as more medium and large prey were eaten. The slope of the increase became steeper with increasing prey-predator size ratio. These observations indicate that components of the predator-prey relationship vary with prey density, contrary to the basic assumptions of functional response equations. Moreover, the results suggest that the effects of prey density change during the ontogeny of predators and prey.

  6. Periodic solutions of multispecies-competition predator-prey system with Holling's type III functional response and prey supplement

    Directory of Open Access Journals (Sweden)

    Jiwei He

    2007-07-01

    Full Text Available In this paper, we consider a nonautonomous multispecies competition predator-prey system with Holling's type III functional response and prey supplement. It is proved that the system is uniformly persistent under some conditions. Furthermore, we show that the system has a unique positive periodic solution which is globally asymptotically stable.

  7. Global Existence of Classical Solutions to a Three-Species Predator-Prey Model with Two Prey-Taxes

    Directory of Open Access Journals (Sweden)

    Chenglin Li

    2012-01-01

    Full Text Available We are concerned with three-species predator-prey model including two prey-taxes and Holling type II functional response under no flux boundary condition. By applying the contraction mapping principle, the parabolic Schauder estimates, and parabolic Lp estimates, we prove that there exists a unique global classical solution of this system.

  8. Singular perturbation method for global stability of ratio-dependent predator-prey models with stage structure for the prey

    Directory of Open Access Journals (Sweden)

    Linfei Nie

    2013-04-01

    Full Text Available In this article, a singular perturbation is introduced to analyze the global asymptotic stability of positive equilibria of ratio-dependent predator-prey models with stage structure for the prey. We prove theoretical results and show numerically that the proposed approach is feasible and efficient.

  9. Modelling the effects of prey size and distribution on prey capture rates of two sympatric marine predators.

    Directory of Open Access Journals (Sweden)

    Chris B Thaxter

    Full Text Available Understanding how prey capture rates are influenced by feeding ecology and environmental conditions is fundamental to assessing anthropogenic impacts on marine higher predators. We compared how prey capture rates varied in relation to prey size, prey patch distribution and prey density for two species of alcid, common guillemot (Uria aalge and razorbill (Alca torda during the chick-rearing period. We developed a Monte Carlo approach parameterised with foraging behaviour from bird-borne data loggers, observations of prey fed to chicks, and adult diet from water-offloading, to construct a bio-energetics model. Our primary goal was to estimate prey capture rates, and a secondary aim was to test responses to a set of biologically plausible environmental scenarios. Estimated prey capture rates were 1.5 ± 0.8 items per dive (0.8 ± 0.4 and 1.1 ± 0.6 items per minute foraging and underwater, respectively for guillemots and 3.7 ± 2.4 items per dive (4.9 ± 3.1 and 7.3 ± 4.0 items per minute foraging and underwater, respectively for razorbills. Based on species' ecology, diet and flight costs, we predicted that razorbills would be more sensitive to decreases in 0-group sandeel (Ammodytes marinus length (prediction 1, but guillemots would be more sensitive to prey patches that were more widely spaced (prediction 2, and lower in prey density (prediction 3. Estimated prey capture rates increased non-linearly as 0-group sandeel length declined, with the slope being steeper in razorbills, supporting prediction 1. When prey patches were more dispersed, estimated daily energy expenditure increased by a factor of 3.0 for guillemots and 2.3 for razorbills, suggesting guillemots were more sensitive to patchier prey, supporting prediction 2. However, both species responded similarly to reduced prey density (guillemot expenditure increased by 1.7; razorbill by 1.6, thus not supporting prediction 3. This bio-energetics approach complements other foraging models

  10. Modelling the effects of prey size and distribution on prey capture rates of two sympatric marine predators.

    Science.gov (United States)

    Thaxter, Chris B; Daunt, Francis; Grémillet, David; Harris, Mike P; Benvenuti, Silvano; Watanuki, Yutaka; Hamer, Keith C; Wanless, Sarah

    2013-01-01

    Understanding how prey capture rates are influenced by feeding ecology and environmental conditions is fundamental to assessing anthropogenic impacts on marine higher predators. We compared how prey capture rates varied in relation to prey size, prey patch distribution and prey density for two species of alcid, common guillemot (Uria aalge) and razorbill (Alca torda) during the chick-rearing period. We developed a Monte Carlo approach parameterised with foraging behaviour from bird-borne data loggers, observations of prey fed to chicks, and adult diet from water-offloading, to construct a bio-energetics model. Our primary goal was to estimate prey capture rates, and a secondary aim was to test responses to a set of biologically plausible environmental scenarios. Estimated prey capture rates were 1.5 ± 0.8 items per dive (0.8 ± 0.4 and 1.1 ± 0.6 items per minute foraging and underwater, respectively) for guillemots and 3.7 ± 2.4 items per dive (4.9 ± 3.1 and 7.3 ± 4.0 items per minute foraging and underwater, respectively) for razorbills. Based on species' ecology, diet and flight costs, we predicted that razorbills would be more sensitive to decreases in 0-group sandeel (Ammodytes marinus) length (prediction 1), but guillemots would be more sensitive to prey patches that were more widely spaced (prediction 2), and lower in prey density (prediction 3). Estimated prey capture rates increased non-linearly as 0-group sandeel length declined, with the slope being steeper in razorbills, supporting prediction 1. When prey patches were more dispersed, estimated daily energy expenditure increased by a factor of 3.0 for guillemots and 2.3 for razorbills, suggesting guillemots were more sensitive to patchier prey, supporting prediction 2. However, both species responded similarly to reduced prey density (guillemot expenditure increased by 1.7; razorbill by 1.6), thus not supporting prediction 3. This bio-energetics approach complements other foraging models in

  11. Modelling the Effects of Prey Size and Distribution on Prey Capture Rates of Two Sympatric Marine Predators

    Science.gov (United States)

    Thaxter, Chris B.; Daunt, Francis; Grémillet, David; Harris, Mike P.; Benvenuti, Silvano; Watanuki, Yutaka; Hamer, Keith C.; Wanless, Sarah

    2013-01-01

    Understanding how prey capture rates are influenced by feeding ecology and environmental conditions is fundamental to assessing anthropogenic impacts on marine higher predators. We compared how prey capture rates varied in relation to prey size, prey patch distribution and prey density for two species of alcid, common guillemot (Uria aalge) and razorbill (Alca torda) during the chick-rearing period. We developed a Monte Carlo approach parameterised with foraging behaviour from bird-borne data loggers, observations of prey fed to chicks, and adult diet from water-offloading, to construct a bio-energetics model. Our primary goal was to estimate prey capture rates, and a secondary aim was to test responses to a set of biologically plausible environmental scenarios. Estimated prey capture rates were 1.5±0.8 items per dive (0.8±0.4 and 1.1±0.6 items per minute foraging and underwater, respectively) for guillemots and 3.7±2.4 items per dive (4.9±3.1 and 7.3±4.0 items per minute foraging and underwater, respectively) for razorbills. Based on species' ecology, diet and flight costs, we predicted that razorbills would be more sensitive to decreases in 0-group sandeel (Ammodytes marinus) length (prediction 1), but guillemots would be more sensitive to prey patches that were more widely spaced (prediction 2), and lower in prey density (prediction 3). Estimated prey capture rates increased non-linearly as 0-group sandeel length declined, with the slope being steeper in razorbills, supporting prediction 1. When prey patches were more dispersed, estimated daily energy expenditure increased by a factor of 3.0 for guillemots and 2.3 for razorbills, suggesting guillemots were more sensitive to patchier prey, supporting prediction 2. However, both species responded similarly to reduced prey density (guillemot expenditure increased by 1.7; razorbill by 1.6), thus not supporting prediction 3. This bio-energetics approach complements other foraging models in predicting likely

  12. Secondary cell wall composition and candidate gene expression in developing willow (Salix purpurea) stems.

    Science.gov (United States)

    Wan, Yongfang; Gritsch, Cristina; Tryfona, Theodora; Ray, Mike J; Andongabo, Ambrose; Hassani-Pak, Keywan; Jones, Huw D; Dupree, Paul; Karp, Angela; Shewry, Peter R; Mitchell, Rowan A C

    2014-05-01

    The properties of the secondary cell wall (SCW) in willow largely determine the suitability of willow biomass feedstock for potential bioenergy and biofuel applications. SCW development has been little studied in willow and it is not known how willow compares with model species, particularly the closely related genus Populus. To address this and relate SCW synthesis to candidate genes in willow, a tractable bud culture-derived system was developed in Salix purpurea, and cell wall composition and RNA-Seq transcriptome were followed in stems during early development. A large increase in SCW deposition in the period 0-2 weeks after transfer to soil was characterised by a big increase in xylan content, but no change in the frequency of substitution of xylan with glucuronic acid, and increased abundance of putative transcripts for synthesis of SCW cellulose, xylan and lignin. Histochemical staining and immunolabeling revealed that increased deposition of lignin and xylan was associated with xylem, xylem fibre cells and phloem fibre cells. Transcripts orthologous to those encoding xylan synthase components IRX9 and IRX10 and xylan glucuronyl transferase GUX1 in Arabidopsis were co-expressed, and showed the same spatial pattern of expression revealed by in situ hybridisation at four developmental stages, with abundant expression in proto-xylem, xylem fibre and ray parenchyma cells and some expression in phloem fibre cells. The results show a close similarity with SCW development in Populus species, but also give novel information on the relationship between spatial and temporal variation in xylan-related transcripts and xylan composition.

  13. PRODUCCIÓN DE Echinacea purpurea EN TRES LOCALIDADES DE COSTA RICA

    Directory of Open Access Journals (Sweden)

    Jorge Loaiza

    2005-01-01

    Full Text Available Se estudió la producción de la planta medicinal Echinacea purpurea en 3 localida- des de Costa Rica: Los Santos, a 1650 msnm, temperatura máxima de 26,5°C y mínima de 15,5°C, precipitación promedio de 2635 mm año -1, y suelos franco-arcillo-arenosos de alta fertilidad; Santa Bárbara, a 1250 msnm,temperatura máxima de 27,4°C y mínima de 16,9°C, precipitación promedio de 2924 mm año -1, y suelos francos de fertilidad media; y, Ojo de Agua a 850 msnm, temperatura máxima de 29,1°C y mínima de 19,1°C, precipitación promedio de 2302 mm año -1, y suelos franco-arenosos de fertilidad baja. La mayor cantidad de follaje y raíz se produjo en la zona de Los Santos, seguida por Santa Bárbara y Ojo de Agua, respectivamente. Aun cuando en la zona de Los Santos la densidad de siembra fue solo de 112500 plantas ha-1 comparada con 243000 plantas ha-1 en las otras 2 localidades; parece que las condiciones climáticas prevalecientes a la altura de Los Santos, así como las prácticas culturales utilizadas, favorecieron no sólo la producción de materia seca sino también la acumulación de los metabolitos secundarios de interés. El ingreso económico neto obtenido en la zona de Los Santos fue 47 y 59% mayor que en Santa Bárbara y Ojo de Agua, respectivamente.

  14. Echinacea purpurea L. in children: safety, tolerability, compliance, and clinical effectiveness in upper respiratory tract infections.

    Science.gov (United States)

    Saunders, Paul Richard; Smith, Fraser; Schusky, Read Weaver

    2007-11-01

    Echinacea purpurea (L.) Moench was mistakenly taken from North America to Germany in 1939 where it was cultivated and various extractions were prepared and subsequently used to treat upper respiratory tract infections. Parents often administer Echinacea to their children, but safety data on the use of Echinacea in Canadian children is lacking. A screening history, physical examination, and daily record of symptoms from an initial visit through to a the follow-up visit 13 days later were used to increase patient safety. Each subject was administered an aerial part Echinacea extract. The dose was based on age (2.5 mL three times per day for children aged 2-5 years, and 5 mL two times per day for children aged 6-12 years) and administered for 10 days in an open-label trial. A rating scale was used to measure tolerance to the treatment. We assessed the safety and compliance of use of the Echinacea extract by measuring the amount of extract returned at the end of the study, having the parents complete and return a daily symptom diary, and recording the subjects' use of other natural health products or medications during the trial. Clinical effectiveness of the Echinacea extract could not be accurately assessed because of the small trial size and because the extract had been administered when some of the subjects had an upper respiratory tract infection that had begun 1 or more days prior to the study; however, each subject's symptoms improved. No allergic or adverse reaction occurred and no safety issues arose.

  15. Echinacea purpurea (L.) Moench modulates human T-cell cytokine response☆

    Science.gov (United States)

    Fonseca, Fabiana N.; Papanicolaou, Genovefa; Lin, Hong; Lau, Clara B.S.; Kennelly, Edward J.; Cassileth, Barrie R.; Cunningham-Rundles, Susanna

    2014-01-01

    The study objective was to evaluate the composition of a neutral and weakly acidic water-soluble extract from Echinacea purpurea (L.) Moench (EchNWA) previously shown to modify murine influenza infection, and to assess immunomodulatory effects on human T-cells. EchNWA extract from fresh aerial parts was extracted with water, ethanolic precipitation, and size-exclusion chromatography. The chemical profile of EchNWA was characterized by chromatography (size-exclusion, HPLC, GC–MS), and small molecule finger-print analysis performed by HPLC–PDA. Jurkat T-cells at high and low cell density were pretreated or not with doses of EchNWA, followed by activation with phorbol 12-myristate 13-acetate plus ionomycin (PMA+I). Interleukin-2 (IL-2) and interferon gamma (IFNg) cytokine secretions were measured by multi-cytokine luminex technology. Results showed that EchNWA contains 80% polysaccharides, predominantly a 10 kDa entity; phenolic compounds, cynarin, cichoric and caftaric acids, but no detectable alkylamides. Cytokine production required stimulation and was lower after PMA+I activation in high-density compared to low-density conditions. EchNWA mediated a strong dose-dependent enhancement of high-density T-cell production of IL-2 and IFNg response to PMA+I. EchNWA alone did not stimulate T-cells. EchNWA enhanced mean fluorescence intensity of IL-2 in Jurkat T-cells activated by PMA+1 or ionomycin alone. Conversely EchNWA mediated modest but significant suppression of IFNg response and reduced the percentage of CD25+ T-cells under low-density conditions. Conclusions are that EchNWA polysaccharides, but not phenolic compounds have dose-related adjuvant effects on human T-cell cytokine responses characterized by enhancing and suppressive effects that are regulated by T-cell density. PMID:24434371

  16. Echinacea purpurea (L.) Moench modulates human T-cell cytokine response.

    Science.gov (United States)

    Fonseca, Fabiana N; Papanicolaou, Genovefa; Lin, Hong; Lau, Clara B S; Kennelly, Edward J; Cassileth, Barrie R; Cunningham-Rundles, Susanna

    2014-03-01

    The study objective was to evaluate the composition of a neutral and weakly acidic water-soluble extract from Echinacea purpurea (L.) Moench (EchNWA) previously shown to modify murine influenza infection, and to assess immunomodulatory effects on human T-cells. EchNWA extract from fresh aerial parts was extracted with water, ethanolic precipitation, and size-exclusion chromatography. The chemical profile of EchNWA was characterized by chromatography (size-exclusion, HPLC, GC-MS), and small molecule fingerprint analysis performed by HPLC-PDA. Jurkat T-cells at high and low cell density were pretreated or not with doses of EchNWA, followed by activation with phorbol 12-myristate 13-acetate plus ionomycin (PMA+I). Interleukin-2 (IL-2) and interferon gamma (IFNg) cytokine secretions were measured by multi-cytokine luminex technology. Results showed that EchNWA contains 80% polysaccharides, predominantly a 10kDa entity; phenolic compounds, cynarin, cichoric and caftaric acids, but no detectable alkylamides. Cytokine production required stimulation and was lower after PMA+I activation in high-density compared to low-density conditions. EchNWA mediated a strong dose-dependent enhancement of high-density T-cell production of IL-2 and IFNg response to PMA+I. EchNWA alone did not stimulate T-cells. EchNWA enhanced mean fluorescence intensity of IL-2 in Jurkat T-cells activated by PMA+1 or ionomycin alone. Conversely EchNWA mediated modest but significant suppression of IFNg response and reduced the percentage of CD25+ T-cells under low-density conditions. Conclusions are that EchNWA polysaccharides, but not phenolic compounds have dose-related adjuvant effects on human T-cell cytokine responses characterized by enhancing and suppressive effects that are regulated by T-cell density. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Effect of gibberellic acid, stratification and salinity on seed germination of Echinacea purpurea cv. Magnus

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    Zadeh Shamila Yadolahi

    2015-09-01

    Full Text Available This study was conducted in order to determine the appropriate treatment for breaking dormancy and the effect of salinity on seed germination of purple coneflower (Echinacea purpurea cv. Magnus, in two separate experiments. In the first experiment, five levels of gibberellic acid (GA3 (0, 250, 500, 1000, and 1500 mg×L−1 with four levels of cold moist stratification period of seeds at 5°C (0, 5, 10 and 15 days were launched. A factorial experiment was conducted in a completely randomized design with four replications. The statistical analysis showed that concentration of 250 mg×L−1 GA3 with 10 days of cold moist chilling significantly increased the percentage of germination of normal seedlings and reduced the mean time of germination. In the second experiment, the seeds were chilled for 10 days at 5°C and half of them treated with 250 mg×L−1 GA3 for 24 hours. The seeds treated with GA3, and those non-treated were subjected to NaCl for salinity stress. The experiment was conducted using five salinity levels (0, 20, 40, 60 and 80 mM NaCl in four replications in a completely randomized design. The results showed that purple coneflower is highly sensitive to salinity in the germination stage. The results also showed that by increasing salinity levels, the percentage of germination and normal seedlings significantly decreased and the mean time to germination increased, compared to the control treatment. But the seeds treated with GA3 showed higher viability and better performance under salinity stress condition.

  18. Effects of cichoric acid extract from Echinacea purpurea on collagen-induced arthritis in rats.

    Science.gov (United States)

    Jiang, Ling; Li, Weizu; Wang, Yuchan; Zhang, Xiaosu; Yu, Deqiang; Yin, Yanyan; Xie, Zhongwen; Yuan, Yi

    2014-01-01

    Cichoric acid extract (CAE) from Echinacea purpurea L. was used to investigate the anti-arthritic effect by using collagen-induced arthritis (CIA) rat model. The hind paw swelling volume and the body weight were measured and recorded. All the drug solutions were administered orally to rats for a total of 28 days. On day 28, the rats were anaesthetized and decapitated. The thymus and spleen were weighed for the determination of the organ index. The concentration of tumor necrosis factor alpha (TNFα), interleukin-1 beta (IL-1β) and prostaglandin E2 (PGE-2) in the serum was measured using commercially available ELISA kits. Total and phosphor-NF-κB and Cox-2 protein expression in synovial tissues were determined by histological slides quantification and western blot analysis. Our data showed that administration of all doses of CAE (8, 16, and 32 mg/kg) significantly decreased the paw swelling, restored body weight gain and decreased the organ index of the thymus and spleen compared with that of the CIA group. CAE (8, 16, and 32 mg/kg) treatment significantly reduced the levels of TNFα, IL-1β and PGE-2 in serum compared with the CIA group. Histopathological analysis demonstrated that CAE has obvious anti-arthritic activity. In addition, CAE (32 mg/kg) significantly decreased the levels of nuclear factor-κB (NF-κB), TNFα and cyclooxygenase 2 (Cox-2) in synovium tissues of the ankle joint compared with the CIA group. Furthermore, CAE administration significantly decreased the protein expression of phosphor-NF-κB and Cox-2 in synovium tissues of the knee joint compared with the CIA group. The results suggest that the anti-inflammatory activity of CAE may account for its anti-arthritic effect, and CAE could be a potential therapeutic drug for the treatment of rheumatoid arthritis (RA).

  19. Veterinary Aspects of Bird of Prey Reproduction.

    Science.gov (United States)

    Bailey, Tom A; Lierz, Michael

    2017-05-01

    Captive breeding has contributed to successful restoration of many species of birds of prey. Avicultural techniques pioneered by raptor breeders include double clutching, direct fostering, cross-fostering, hatch and switch, hacking, imprinting male and female falcons for semen collection, and artificial insemination techniques. However, reproductive failure occurs related to management problems, including hygiene measures, food quality issues, breeding flock structure, or individual health issues of breeding birds. These may result in non-egg laying females, low-quality eggs, or infertile eggs caused by male infertility. Veterinary care of breeding collections is extremely important. This article provides an overview of veterinary involvement in raptor breeding projects. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Research Advances in Immunomodulation of Echinacea purpurea. in China%国内紫锥菊免疫调节作用研究进展

    Institute of Scientific and Technical Information of China (English)

    唐雪莲; 付京城; 李洪; 付京花

    2012-01-01

    紫锥菊属植物,是原产于美洲的一类菊科野生花卉。紫锥菊以其免疫调节作用闻名于世。近年来,国内引种成功,其各种药理作用在人类、畜牧业以及水产养殖业有了广泛的研究。综述国内紫锥菊免疫调节作用在不同行业的研究进展,为紫锥菊在国内的应用提供参考。%The Echinacea purpurea., one of the plants of Compositae originated from America, has been widely used for centuries in North America and later in Europe for many therapeutic purposes. In resent years, the Echinacea purpurea. was introduced successfully in China and the pharmacological effects were widely researched in human, animal husbandry and aquiculture respectively. The advances in immunomodulation studies on Echinacea purpurea. in China were reviewed to provide the references for application of Echinacea purpurea .

  1. Contact dermatitis as an adverse reaction to some topically used European herbal medicinal products - part 2: Echinacea purpurea-Lavandula angustifolia.

    Science.gov (United States)

    Gangemi, Sebastiano; Minciullo, Paola L; Miroddi, Marco; Chinou, Ioanna; Calapai, Gioacchino; Schmidt, Richard J

    2015-04-01

    This review focuses on contact dermatitis as an adverse effect of a selection of topically used herbal medicinal products for which the European Medicines Agency has completed an evaluation up to the end of November 2013 and for which a Community herbal monograph has been produced. Part 2: Echinacea purpurea Moench-Lavandula angustifolia Mill.

  2. Draft Genome Sequence of Pseudomonas sp. EpS/L25, Isolated from the Medicinal Plant Echinacea purpurea and Able To Synthesize Antimicrobial Compounds

    Science.gov (United States)

    Presta, Luana; Bosi, Emanuele; Fondi, Marco; Maida, Isabel; Perrin, Elena; Miceli, Elisangela; Maggini, Valentina; Bogani, Patrizia; Firenzuoli, Fabio; Di Pilato, Vincenzo; Rossolini, Gian Maria; Mengoni, Alessio

    2016-01-01

    We announce here the draft genome sequence of Pseudomonas sp. strain EpS/L25, isolated from the stem/leaves of the medicinal plant Echinacea purpurea. This genome will allow for comparative genomics in order to identify genes associated with the production of bioactive compounds and antibiotic resistance. PMID:27151804

  3. THE EFFECT OF THE TREATMENTS WITH GAMMA RADIATIONS ON THE CONTENT OF NUCLEIC ACIDS TO THE SPECIES OF HYPERICUM PERFORATUM L. AND ECHINACEA PURPUREA (L MOENCH

    Directory of Open Access Journals (Sweden)

    Daniela Luminita Ichim

    2005-08-01

    Full Text Available The gamma radiations determined to the species of Echinacea purpurea (L Moench on increase of the quantity of DNA, comparatively to control and to the species of Hypericum perforatum (L., the decrease of the quantity of DNA (excepting the30 Gy dose witch hand a stimulative effect.

  4. A Predator-Prey Gompertz Model with Time Delay and Impulsive Perturbations on the Prey

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    Jianwen Jia

    2009-01-01

    Full Text Available We introduce and study a Gompertz model with time delay and impulsive perturbations on the prey. By using the discrete dynamical system determined by the stroboscopic map, we obtain the sufficient conditions for the existence and global attractivity of the “predator-extinction” periodic solution. With the theory on the delay functional and impulsive differential equation, we obtain the appropriate condition for the permanence of the system.

  5. Competing conservation objectives for predators and prey: estimating killer whale prey requirements for Chinook salmon.

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    Rob Williams

    Full Text Available Ecosystem-based management (EBM of marine resources attempts to conserve interacting species. In contrast to single-species fisheries management, EBM aims to identify and resolve conflicting objectives for different species. Such a conflict may be emerging in the northeastern Pacific for southern resident killer whales (Orcinus orca and their primary prey, Chinook salmon (Oncorhynchus tshawytscha. Both species have at-risk conservation status and transboundary (Canada-US ranges. We modeled individual killer whale prey requirements from feeding and growth records of captive killer whales and morphometric data from historic live-capture fishery and whaling records worldwide. The models, combined with caloric value of salmon, and demographic and diet data for wild killer whales, allow us to predict salmon quantities needed to maintain and recover this killer whale population, which numbered 87 individuals in 2009. Our analyses provide new information on cost of lactation and new parameter estimates for other killer whale populations globally. Prey requirements of southern resident killer whales are difficult to reconcile with fisheries and conservation objectives for Chinook salmon, because the number of fish required is large relative to annual returns and fishery catches. For instance, a U.S. recovery goal (2.3% annual population growth of killer whales over 28 years implies a 75% increase in energetic requirements. Reducing salmon fisheries may serve as a temporary mitigation measure to allow time for management actions to improve salmon productivity to take effect. As ecosystem-based fishery management becomes more prevalent, trade-offs between conservation objectives for predators and prey will become increasingly necessary. Our approach offers scenarios to compare relative influence of various sources of uncertainty on the resulting consumption estimates to prioritise future research efforts, and a general approach for assessing the extent of

  6. Wave propagation in predator-prey systems

    Science.gov (United States)

    Fu, Sheng-Chen; Tsai, Je-Chiang

    2015-12-01

    In this paper, we study a class of predator-prey systems of reaction-diffusion type. Specifically, we are interested in the dynamical behaviour for the solution with the initial distribution where the prey species is at the level of the carrying capacity, and the density of the predator species has compact support, or exponentially small tails near x=+/- ∞ . Numerical evidence suggests that this will lead to the formation of a pair of diverging waves propagating outwards from the initial zone. Motivated by this phenomenon, we establish the existence of a family of travelling waves with the minimum speed. Unlike the previous studies, we do not use the shooting argument to show this. Instead, we apply an iteration process based on Berestycki et al 2005 (Math Comput. Modelling 50 1385-93) to construct a set of super/sub-solutions. Since the underlying system does not enjoy the comparison principle, such a set of super/sub-solutions is not based on travelling waves, and in fact the super/sub-solutions depend on each other. With the aid of the set of super/sub-solutions, we can construct the solution of the truncated problem on the finite interval, which, via the limiting argument, can in turn generate the wave solution. There are several advantages to this approach. First, it can remove the technical assumptions on the diffusivities of the species in the existing literature. Second, this approach is of PDE type, and hence it can shed some light on the spreading phenomenon indicated by numerical simulation. In fact, we can compute the spreading speed of the predator species for a class of biologically acceptable initial distributions. Third, this approach might be applied to the study of waves in non-cooperative systems (i.e. a system without a comparison principle).

  7. The effect of structural complexity, prey density, and "predator-free space" on prey survivorship at created oyster reef mesocosms.

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    Austin T Humphries

    Full Text Available Interactions between predators and their prey are influenced by the habitat they occupy. Using created oyster (Crassostrea virginica reef mesocosms, we conducted a series of laboratory experiments that created structure and manipulated complexity as well as prey density and "predator-free space" to examine the relationship between structural complexity and prey survivorship. Specifically, volume and spatial arrangement of oysters as well as prey density were manipulated, and the survivorship of prey (grass shrimp, Palaemonetes pugio in the presence of a predator (wild red drum, Sciaenops ocellatus was quantified. We found that the presence of structure increased prey survivorship, and that increasing complexity of this structure further increased survivorship, but only to a point. This agrees with the theory that structural complexity may influence predator-prey dynamics, but that a threshold exists with diminishing returns. These results held true even when prey density was scaled to structural complexity, or the amount of "predator-free space" was manipulated within our created reef mesocosms. The presence of structure and its complexity (oyster shell volume were more important in facilitating prey survivorship than perceived refugia or density-dependent prey effects. A more accurate indicator of refugia might require "predator-free space" measures that also account for the available area within the structure itself (i.e., volume and not just on the surface of a structure. Creating experiments that better mimic natural conditions and test a wider range of "predator-free space" are suggested to better understand the role of structural complexity in oyster reefs and other complex habitats.

  8. The effect of structural complexity, prey density, and "predator-free space" on prey survivorship at created oyster reef mesocosms

    Science.gov (United States)

    Humphries, Austin T.; La Peyre, Megan K.; Decossas, Gary A.

    2011-01-01

    Interactions between predators and their prey are influenced by the habitat they occupy. Using created oyster (Crassostrea virginica) reef mesocosms, we conducted a series of laboratory experiments that created structure and manipulated complexity as well as prey density and “predator-free space” to examine the relationship between structural complexity and prey survivorship. Specifically, volume and spatial arrangement of oysters as well as prey density were manipulated, and the survivorship of prey (grass shrimp, Palaemonetes pugio) in the presence of a predator (wild red drum, Sciaenops ocellatus) was quantified. We found that the presence of structure increased prey survivorship, and that increasing complexity of this structure further increased survivorship, but only to a point. This agrees with the theory that structural complexity may influence predator-prey dynamics, but that a threshold exists with diminishing returns. These results held true even when prey density was scaled to structural complexity, or the amount of “predator-free space” was manipulated within our created reef mesocosms. The presence of structure and its complexity (oyster shell volume) were more important in facilitating prey survivorship than perceived refugia or density-dependent prey effects. A more accurate indicator of refugia might require “predator-free space” measures that also account for the available area within the structure itself (i.e., volume) and not just on the surface of a structure. Creating experiments that better mimic natural conditions and test a wider range of “predator-free space” are suggested to better understand the role of structural complexity in oyster reefs and other complex habitats.

  9. Deuterium NMR used to indicate a common mechanism for the biosynthesis of ricinoleic acid by Ricinus communis and Claviceps purpurea.

    Science.gov (United States)

    Billault, Isabelle; Mantle, Peter G; Robins, Richard J

    2004-03-17

    Previous studies have shown that ricinoleic acid from castor bean oil of Ricinus communis is synthesized by the direct hydroxyl substitution of oleate, while it has been proposed that ricinoleate is formed by hydration of linoleate in the ergot fungus Claviceps purpurea. The mechanism of the enzymes specific to ricinoleate synthesis has not yet been established, but hydroxylation and desaturation of fatty acids in plants apparently involve closely related mechanisms. As mechanistic differences in the enzymes involved in the biosynthesis of natural products can lead to different isotopic distributions in the product, we could expect ricinoleate isolated from castor or ergot oil to show distinct (2)H distribution patterns. To obtain information concerning the substrate and isotope effects that occur during the biosynthesis of ricinoleate, the site-specific natural deuterium distributions in methyl ricinoleate isolated from castor oil and in methyl ricinoleate and methyl linoleate isolated from ergot oils have been measured by quantitative (2)H NMR. First, the deuterium profiles for methyl ricinoleate from the plant and fungus are equivalent. Second, the deuterium profile for methyl linoleate from ergot is incompatible with this chemical species being the precursor of methyl ricinoleate. Hence, it is apparent that 12-hydroxylation in C. purpurea is consistent with the biosynthetic mechanisms proposed for R. communis and is compatible with the general fundamental mechanistic similarities between hydroxylation and desaturation previously proposed for plant fatty acid biosynthesis.

  10. Hepatoprotective Activity of Methanolic Extract of Bauhinia purpurea Leaves against Paracetamol-Induced Hepatic Damage in Rats

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    F. Yahya

    2013-01-01

    Full Text Available In an attempt to further establish the pharmacological properties of Bauhinia purpurea (Fabaceae, hepatoprotective potential of methanol extract of B. purpurea leaves (MEBP was investigated using the paracetamol- (PCM- induced liver toxicity in rats. Five groups of rats (n=6 were used and administered orally once daily with 10% DMSO (negative control, 200 mg/kg silymarin (positive control, or MEBP (50, 250, and 500 mg/kg for 7 days, followed by the hepatotoxicity induction using paracetamol (PCM. The blood samples and livers were collected and subjected to biochemical and microscopical analysis. The extract was also subjected to antioxidant study using the 2, 2-diphenyl-1-picrylhydrazyl (DPPH radical scavenging assay with the total phenolic content (TPC also determined. From the histological observation, lymphocyte infiltration and marked necrosis were observed in PCM-treated groups (negative control, whereas maintenance of the normal hepatic structural was observed in group pretreated with silymarin and MEBP. Hepatotoxic rats pretreated with silymarin or MEBP exhibited significant decrease (P<0.05 in ALT and AST enzyme level. Moreover, the extract also exhibited antioxidant activity and contained high TPC. In conclusion, MEBP exerts potential hepatoprotective activity that could be partly attributed to its antioxidant activity and high phenolic content and thus warrants further investigation.

  11. Growing environment and nutrient availability affect the content of some phenolic compounds in Echinacea purpurea and Echinacea angustifolia.

    Science.gov (United States)

    Zheng, Youbin; Dixon, Mike; Saxena, Praveen K

    2006-12-01

    Medicinal plant production is different from other agricultural production systems in that the plants are grown for the production of specific phytochemical(s) for human use. To address this need, a Good Manufacturing Practice (GMP)-compliant, controlled-environment production system was developed for production of Echinacea purpurea and Echinacea angustifolia. Within the prototype facility, the growing systems, nutrient availability, water and physical environment were highly controlled. The current study was designed to evaluate the effects of different hydroponic systems, nutrient solution NO (3)(-)/NH (4)(+) ratios and mild water stress on the content of some phenolic compounds in Echinacea plants. The deep-flow solution culture system in which the plant roots were continuously immersed in the nutrient solutions was optimum for the growth of E. purpurea. Higher concentrations of caftaric acid, cynarin and echinacoside were produced in E. angustifolia plants grown in the soil-based growing media while the plants grown in the deep-flow solution system had higher levels of cichoric acid. Altering the NO (3)(-)/NH (4)(+) ratio or limited water stress did not have any significant effect on the phytochemical content of Echinacea plants. Echinacea plants grown in the controlled environment systems had higher or similar amounts of cynarin, caftaric acid, echinacoside and cichoric acid as previously reported in the literature for both field-cultivated and wild-harvested Echinacea plants. This growing system offers the advantages of year-round crop production with minimal contamination by environmental pollutants and common microbes.

  12. Alkamides and a neolignan from Echinacea purpurea roots and the interaction of alkamides with G-protein-coupled cannabinoid receptors.

    Science.gov (United States)

    Hohmann, Judit; Rédei, Dóra; Forgo, Peter; Szabó, Pál; Freund, Tamás F; Haller, József; Bojnik, Engin; Benyhe, Sándor

    2011-10-01

    Multiple chromatographic separations of the CHCl₃-soluble extract of the roots of Echinacea purpurea led to the isolation of 19 compounds. Four natural products, three alkamides and nitidanin diisovalerianate, were identified, and five further compounds were detected for the first time in this species. Additionally, 10 known E. purpurea metabolites were isolated. The structures were determined by mass spectrometry and advanced 1D and 2D NMR techniques. The bioactivity of the isolated compounds was studied in [³⁵S]GTPγS-binding experiments performed on rat brain membrane preparations. Both partial and inverse agonist compounds for cannabinoid (CB1) receptors were identified among the metabolites, characterized by weak to moderate interactions with the G-protein signaling mechanisms. The G-protein-modulating activities of the Echinacea compounds are rather far from the full agonist effects seen with the CB1 receptor agonist reference compound arachidonyl-2'-chloroethylamide (ACEA). However, upon coadministration with ACEA, a number of them proved capable of inhibiting the stimulation of the pure agonist, thereby demonstrating cannabinoid receptor antagonist properties. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. Echinacea purpurea Extract Polarizes M1 Macrophages in Murine Bone Marrow-Derived Macrophages Through the Activation of JNK.

    Science.gov (United States)

    Fu, Aikun; Wang, Yang; Wu, Yanping; Chen, Hongliang; Zheng, Shasha; Li, Yali; Xu, Xin; Li, Weifen

    2017-09-01

    Echinacea purpurea is an indigenous North American purple cone flower used by North Americans for treatment of various infectious diseases and wounds. This study investigated the effect of polysaccharide enriched extract of Echinacea purpurea (EE) on the polarization of macrophages. The results showed that 100 µg/mL of EE could markedly activate the macrophage by increasing the expression of CD80, CD86, and MHCII molecules. Meanwhile, EE upregulated the markers of classically activated macrophages (M1) such as CCR7 and the production of IL-1β, IL-6, IL-12p70, TNF-αand NO. The functional tests showed that EE enhanced the phagocytic and intracellular bactericidal activity of macrophage against ST. Furthermore, we demonstrated that JNK are required for EE-induced NO and M1-related cytokines production. Together, these results demonstrated that EE can polarize macrophages towards M1 phenotype, which is dependent on the JNK signaling pathways. J. Cell. Biochem. 118: 2664-2671, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  14. Effect of instant controlled pressure drop treatments on the oligosaccharides extractability and microstructure of Tephrosia purpurea seeds.

    Science.gov (United States)

    Amor, Bouthaina Ben; Lamy, Cécile; Andre, Patrice; Allaf, Karim

    2008-12-12

    The study of the oligosaccharides extracted from Tephrosia purpurea seeds was undertaken using the instant controlled pressure drop (DIC) as a pre-treatment prior to conventional solvent extraction. This DIC procedure provided structural modification in terms of expansion, higher porosity and improvement of specific surface area; diffusion of solvent inside such seeds and availability of oligosaccharides increase notably. In this paper, we investigated and quantified the impact of the different DIC operative parameters on the yields of ciceritol and stachyose extracted from T. purpurea seeds. The treatment could be optimized with a steam pressure (P) (P=0.2 MPa), initial water content (W) (W=30% dry basis (DB)) and thermal treatment time (t) (t=30s). By applying DIC treatment in these conditions, the classic process of extraction was intensified in both aspects of yields (145% of ciceritol and 185% of stachyose), and kinetics (1h of extraction time instead of 4h for conventional process). The scanning electron microscopy micrographs provided evident modifications of structure of seeds due to the DIC treatment.

  15. Genotoxicity biomonitoring of sewage in two municipal wastewater treatment plants using the Tradescantia pallida var. purpurea bioassay

    Science.gov (United States)

    Thewes, Márcia Regina; Junior, Delio Endres; Droste, Annette

    2011-01-01

    The genotoxicity of untreated and treated sewage from two municipal wastewater treatment plants (WTP BN and WTP SJN) in the municipality of Porto Alegre, in the southern Brazilian state of Rio Grande do Sul, was evaluated over a one-year period using the Tradescantia pallida var. purpurea (Trad-MCN) bioassay. Inflorescences of T. pallida var. purpurea were exposed to sewage samples in February (summer), April (autumn), July (winter) and October (spring) 2009, and the micronuclei (MCN) frequencies were estimated in each period. The high genotoxicity of untreated sewage from WTP BN in February and April was not observed in treated sewage, indicating the efficiency of treatment at this WTP. However, untreated and treated sewage samples from WTP SJN had high MCN frequencies, except in October, when rainfall may have been responsible for reducing these frequencies at both WTPs. Physicochemical analyses of sewage from both WTPs indicated elevated concentrations of organic matter that were higher at WTP SJN than at WTP BN. Chromium was detected in untreated and treated sewage from WTP SJN, but not in treated sewage from WTP BN. Lead was found in all untreated sewage samples from WTP SJN, but only in the summer and autumn at WTP BN. These results indicate that the short-term Trad-MCN genotoxicity assay may be useful for regular monitoring of municipal WTPs. PMID:22215975

  16. Tactile Experience Shapes Prey-Capture Behavior in Etruscan Shrews

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    Michael eBrecht

    2012-06-01

    Full Text Available A crucial role of tactile experience for the maturation of neural response properties in the somatosensory system is well established, but little is known about the role of tactile experience in the development of tactile behaviors. Here we study how tactile experience affects prey capture behavior in Etruscan shrews, Suncus etruscus. Prey capture in adult shrews is a high-speed behavior that relies on precise attacks guided by tactile Gestalt cues. We studied the role of tactile experience by three different approaches. First, we analyzed the hunting skills of young shrews right after weaning. We found that prey capture in young animals is most but not all aspects similar to that of adults. Second we performed whisker trimming for three to four weeks after birth. Such deprivation resulted in a lasting disruption of prey capture even after whisker re-growth: attacks lacked precise targeting and had a lower success rate. Third, we presented adult shrews with an entirely novel prey species, the giant cockroach. The shape of this roach is very different from the shrew’s normal (cricket prey and the thorax – the preferred point of attack in crickets – is protected a heavy cuticle. Initially shrews attacked giant roaches the same way they attack crickets and targeted the thoracic region. With progressive experience, however, shrews adopted a new attack strategy targeting legs and underside of the roaches while avoiding other body parts. Speed and efficiency of attacks improved. These data suggest that tactile experience shapes prey capture behavior.

  17. Disentangling mite predator-prey relationships by multiplex PCR.

    Science.gov (United States)

    Pérez-Sayas, Consuelo; Pina, Tatiana; Gómez-Martínez, María A; Camañes, Gemma; Ibáñez-Gual, María V; Jaques, Josep A; Hurtado, Mónica A

    2015-11-01

    Gut content analysis using molecular techniques can help elucidate predator-prey relationships in situations in which other methodologies are not feasible, such as in the case of trophic interactions between minute species such as mites. We designed species-specific primers for a mite community occurring in Spanish citrus orchards comprising two herbivores, the Tetranychidae Tetranychus urticae and Panonychus citri, and six predatory mites belonging to the Phytoseiidae family; these predatory mites are considered to be these herbivores' main biological control agents. These primers were successfully multiplexed in a single PCR to test the range of predators feeding on each of the two prey species. We estimated prey DNA detectability success over time (DS50), which depended on the predator-prey combination and ranged from 0.2 to 18 h. These values were further used to weight prey detection in field samples to disentangle the predatory role played by the most abundant predators (i.e. Euseius stipulatus and Phytoseiulus persimilis). The corrected predation value for E. stipulatus was significantly higher than for P. persimilis. However, because this 1.5-fold difference was less than that observed regarding their sevenfold difference in abundance, we conclude that P. persimilis is the most effective predator in the system; it preyed on tetranychids almost five times more frequently than E. stipulatus did. The present results demonstrate that molecular tools are appropriate to unravel predator-prey interactions in tiny species such as mites, which include important agricultural pests and their predators.

  18. Prey detection by vomeronasal chemoreception in a plethodontid salamander.

    Science.gov (United States)

    Placyk, John S; Graves, Brent M

    2002-05-01

    While chemoreception is involved in a wide variety of salamander behaviors, the chemosensory system that mediates specific behaviors is rarely known. We investigated the role of the vomeronasal system (VNS) in foraging behavior of the red-backed salamander (Plethodon cinereus) by manipulating salamanders' abilities to detect nonvolatile chemical cues emitted by potential prey. Subjects received one of three treatments: (1) impaired vomeronasal system, (2) sham manipulation, and (3) no manipulation. The role of the VNS in mediating foraging on motile prey (Drosophila melanogaster) was investigated under three light conditions (bright, dim, dark). Salamanders with impaired VNSs foraged less efficiently than either of the other experimental groups by displaying the longest latency to attack and the lowest rate of prey capture, especially in the absence of visual cues. A second experiment utilized freshly killed prey to determine whether the VNS takes on added importance in the absence of visual or tactile cues associated with moving prey. Animals with impaired VNSs showed a decreased foraging efficiency on stationary prey under both dark and light conditions. In addition, a mark-recapture study of VNS-impaired and sham salamanders in the field also indicated that salamanders with impaired VNSs consumed fewer stationary prey compared to shams. The study indicates that the VNS plays a substantial role in the foraging behavior of the plethodontid salamander, P. cinereus.

  19. Ethanolic Echinacea purpurea Extracts Contain a Mixture of Cytokine-Suppressive and Cytokine-Inducing Compounds, Including Some That Originate from Endophytic Bacteria.

    Directory of Open Access Journals (Sweden)

    Daniel A Todd

    Full Text Available Echinacea preparations, which are used for the prevention and treatment of upper respiratory infections, account for 10% of the dietary supplement market in the U.S., with sales totaling more than $100 million annually. In an attempt to shed light on Echinacea's mechanism of action, we evaluated the effects of a 75% ethanolic root extract of Echinacea purpurea, prepared in accord with industry methods, on cytokine and chemokine production from RAW 264.7 macrophage-like cells. We found that the extract displayed dual activities; the extract could itself stimulate production of the cytokine TNF-α, and also suppress production of TNF-α in response to stimulation with exogenous LPS. Liquid:liquid partitioning followed by normal-phase flash chromatography resulted in separation of the stimulatory and inhibitory activities into different fractions, confirming the complex nature of this extract. We also studied the role of alkylamides in the suppressive activity of this E. purpurea extract. Our fractionation method concentrated the alkylamides into a single fraction, which suppressed production of TNF-α, CCL3, and CCL5; however fractions that did not contain detectable alkylamides also displayed similar suppressive effects. Alkylamides, therefore, likely contribute to the suppressive activity of the extract but are not solely responsible for that activity. From the fractions without detectable alkylamides, we purified xanthienopyran, a compound not previously known to be a constituent of the Echinacea genus. Xanthienopyran suppressed production of TNF-α suggesting that it may contribute to the suppressive activity of the crude ethanolic extract. Finally, we show that ethanolic extracts prepared from E. purpurea plants grown under sterile conditions and from sterilized seeds, do not contain LPS and do not stimulate macrophage production of TNF-α, supporting the hypothesis that the macrophage-stimulating activity in E. purpurea extracts can

  20. Ethanolic Echinacea purpurea Extracts Contain a Mixture of Cytokine-Suppressive and Cytokine-Inducing Compounds, Including Some That Originate from Endophytic Bacteria.

    Science.gov (United States)

    Todd, Daniel A; Gulledge, Travis V; Britton, Emily R; Oberhofer, Martina; Leyte-Lugo, Martha; Moody, Ashley N; Shymanovich, Tatsiana; Grubbs, Laura F; Juzumaite, Monika; Graf, Tyler N; Oberlies, Nicholas H; Faeth, Stanley H; Laster, Scott M; Cech, Nadja B

    2015-01-01

    Echinacea preparations, which are used for the prevention and treatment of upper respiratory infections, account for 10% of the dietary supplement market in the U.S., with sales totaling more than $100 million annually. In an attempt to shed light on Echinacea's mechanism of action, we evaluated the effects of a 75% ethanolic root extract of Echinacea purpurea, prepared in accord with industry methods, on cytokine and chemokine production from RAW 264.7 macrophage-like cells. We found that the extract displayed dual activities; the extract could itself stimulate production of the cytokine TNF-α, and also suppress production of TNF-α in response to stimulation with exogenous LPS. Liquid:liquid partitioning followed by normal-phase flash chromatography resulted in separation of the stimulatory and inhibitory activities into different fractions, confirming the complex nature of this extract. We also studied the role of alkylamides in the suppressive activity of this E. purpurea extract. Our fractionation method concentrated the alkylamides into a single fraction, which suppressed production of TNF-α, CCL3, and CCL5; however fractions that did not contain detectable alkylamides also displayed similar suppressive effects. Alkylamides, therefore, likely contribute to the suppressive activity of the extract but are not solely responsible for that activity. From the fractions without detectable alkylamides, we purified xanthienopyran, a compound not previously known to be a constituent of the Echinacea genus. Xanthienopyran suppressed production of TNF-α suggesting that it may contribute to the suppressive activity of the crude ethanolic extract. Finally, we show that ethanolic extracts prepared from E. purpurea plants grown under sterile conditions and from sterilized seeds, do not contain LPS and do not stimulate macrophage production of TNF-α, supporting the hypothesis that the macrophage-stimulating activity in E. purpurea extracts can originate from endophytic

  1. Predicting prey population dynamics from kill rate, predation rate and predator-prey ratios in three wolf-ungulate systems.

    Science.gov (United States)

    Vucetich, John A; Hebblewhite, Mark; Smith, Douglas W; Peterson, Rolf O

    2011-11-01

    1. Predation rate (PR) and kill rate are both fundamental statistics for understanding predation. However, relatively little is known about how these statistics relate to one another and how they relate to prey population dynamics. We assess these relationships across three systems where wolf-prey dynamics have been observed for 41 years (Isle Royale), 19 years (Banff) and 12 years (Yellowstone). 2. To provide context for this empirical assessment, we developed theoretical predictions of the relationship between kill rate and PR under a broad range of predator-prey models including predator-dependent, ratio-dependent and Lotka-Volterra dynamics. 3. The theoretical predictions indicate that kill rate can be related to PR in a variety of diverse ways (e.g. positive, negative, unrelated) that depend on the nature of predator-prey dynamics (e.g. structure of the functional response). These simulations also suggested that the ratio of predator-to-prey is a good predictor of prey growth rate. That result motivated us to assess the empirical relationship between the ratio and prey growth rate for each of the three study sites. 4. The empirical relationships indicate that PR is not well predicted by kill rate, but is better predicted by the ratio of predator-to-prey. Kill rate is also a poor predictor of prey growth rate. However, PR and ratio of predator-to-prey each explained significant portions of variation in prey growth rate for two of the three study sites. 5. Our analyses offer two general insights. First, Isle Royale, Banff and Yellowstone are similar insomuch as they all include wolves preying on large ungulates. However, they also differ in species diversity of predator and prey communities, exploitation by humans and the role of dispersal. Even with the benefit of our analysis, it remains difficult to judge whether to be more impressed by the similarities or differences. This difficulty nicely illustrates a fundamental property of ecological

  2. Predator cannibalism can intensify negative impacts on heterospecific prey.

    Science.gov (United States)

    Takatsu, Kunio; Kishida, Osamu

    2015-07-01

    Although natural populations consist of individuals with different traits, and the degree of phenotypic variation varies among populations, the impact of phenotypic variation on ecological interactions has received little attention, because traditional approaches to community ecology assume homogeneity of individuals within a population. Stage structure, which is a common way of generating size and developmental variation within predator populations, can drive cannibalistic interactions, which can affect the strength of predatory effects on the predator's heterospecific prey. Studies have shown that predator cannibalism weakens predatory effects on heterospecific prey by reducing the size of the predator population and by inducing less feeding activity of noncannibal predators. We predict, however, that predator cannibalism, by promoting rapid growth of the cannibals, can also intensify predation pressure on heterospecific prey, because large predators have large resource requirements and may utilize a wider variety of prey species. To test this hypothesis, we conducted an experiment in which we created carnivorous salamander (Hynobius retardatus) populations with different stage structures by manipulating the salamander's hatch timing (i.e., populations with large or small variation in the timing of hatching), and explored the resultant impacts on the abundance, behavior, morphology, and life history of the salamander's large heterospecific prey, Rana pirica frog tadpoles. Cannibalism was rare in salamander populations having small hatch-timing variation, but was frequent in those having large hatch-timing variation. Thus, giant salamander cannibals occurred only in the latter. We clearly showed that salamander giants exerted strong predation pressure on frog tadpoles, which induced large behavioral and morphological defenses in the tadpoles and caused them to metamorphose late at large size. Hence, predator cannibalism arising from large variation in the timing

  3. Alternative prey use affects helminth parasite infections in grey wolves.

    Science.gov (United States)

    Friesen, Olwyn C; Roth, James D

    2016-09-01

    Predators affect prey populations not only through direct predation, but also by acting as definitive hosts for their parasites and completing parasite life cycles. Understanding the affects of parasitism on prey population dynamics requires knowing how their predators' parasite community is affected by diet and prey availability. Ungulates, such as moose (Alces americanus) and white-tailed deer (Odocoileus virginianus), are often important prey for wolves (Canis lupus), but wolves also consume a variety of alternative prey, including beaver (Castor canadensis) and snowshoe hare (Lepus americanus). The use of alternative prey, which may host different or fewer parasites than ungulates, could potentially reduce overall abundance of ungulate parasites within the ecosystem, benefiting both wolves and ungulate hosts. We examined parasites in wolf carcasses from eastern Manitoba and estimated wolf diet using stable isotope analysis. Taeniidae cestodes were present in most wolves (75%), reflecting a diet primarily comprised of ungulates, but nematodes were unexpectedly rare. Cestode abundance was negatively related to the wolf's δ(13) C value, indicating diet affects parasite abundance. Wolves that consumed a higher proportion of beaver and caribou (Rangifer tarandus), estimated using Bayesian mixing models, had lower cestode abundance, suggesting the use of these alternative prey can reduce parasite loads. Long-term consumption of beavers may lower the abundance of adult parasites in wolves, eventually lowering parasite density in the region and ultimately benefiting ungulates that serve as intermediate hosts. Thus, alternative prey can affect both predator-prey and host-parasite interactions and potentially affect food web dynamics. © 2016 The Authors. Journal of Animal Ecology © 2016 British Ecological Society.

  4. Individual prey choices of octopuses: Are they generalist or specialist?

    Institute of Scientific and Technical Information of China (English)

    Jennifer A. MATHER; Tatiana S. LEITE; Allan T. BATISTA

    2012-01-01

    Prey choice is often evaluated at the species or population level.Here,we analyzed the diet of octopuses of different populations with the aim to assess the importance of individual feeding habits as a factor affecting prey choice.Two methods were used,an assessment of the extent to which an individual octopus made choices of species representative of those population (PSi and IS) and 25% cutoff values for number of choices and percentage intake of individual on their prey.In one population of Octopus cf vulgaris in Bermuda individuals were generaiist by IS=0.77,but most chose many prey of the same species,and were specialists on it by >75% intake.Another population had a wider prey selection,still generalist with PSi=0.66,but two individuals specialized by choices.In Bonaire,there was a wide range of prey species chosen,and the population was specialists by IS=0.42.Individual choices revealed seven specialists and four generalists.A population of Octopus cyanea in Hawaii all had similar choices of crustaceans,so the population was generalist by IS with 0.74.But by individual choices,three were considered a specialist.A population of Enteroctopus dofleini from Puget Sound had a wide range of preferences,in which seven were also specialists,IS=0.53.By individual choices,thirteen were also specialists.Given the octopus specialty of learning during foraging,we hypothesize that both localized prey availability and individual personality differences could influence the exploration for prey and this translates into different prey choices across individuals and populations showed in this study.

  5. Individual prey choices of octopuses: Are they generalist or specialist?

    Directory of Open Access Journals (Sweden)

    Jennifer A. MATHER, Tatiana S. LEITE, Allan T. BATISTA

    2012-08-01

    Full Text Available Prey choice is often evaluated at the species or population level. Here, we analyzed the diet of octopuses of different populations with the aim to assess the importance of individual feeding habits as a factor affecting prey choice. Two methods were used, an assessment of the extent to which an individual octopus made choices of species representative of those population (PSi and IS and 25% cutoff values for number of choices and percentage intake of individual on their prey. In one population of Octopus cf vulgaris in Bermuda individuals were generalist by IS=0.77, but most chose many prey of the same species, and were specialists on it by >75% intake. Another population had a wider prey selection, still generalist with PSi=0.66, but two individuals specialized by choices. In Bonaire, there was a wide range of prey species chosen, and the population was specialists by IS= 0.42. Individual choices revealed seven specialists and four generalists. A population of Octopus cyanea in Hawaii all had similar choices of crustaceans, so the population was generalist by IS with 0.74. But by individual choices, three were considered a specialist. A population of Enteroctopus dofleini from Puget Sound had a wide range of preferences, in which seven were also specialists, IS=0.53. By individual choices, thirteen were also specialists. Given the octopus specialty of learning during foraging, we hypothesize that both localized prey availability and individual personality differences could influence the exploration for prey and this translates into different prey choices across individuals and populations showed in this study [Current Zoology 58 (4: 597-603, 2012].

  6. A self-organized system of smart preys and predators

    Energy Technology Data Exchange (ETDEWEB)

    Rozenfeld, Alejandro F. [Instituto de Investigaciones Fisicoquimicas Teoricas y Aplicadas (INIFTA), Facultad de Ciencias Exactas, UNLP, CONICET, Suc. 4, C.C. 16 (1900) La Plata (Argentina); Albano, Ezequiel V. [Instituto de Investigaciones Fisicoquimicas Teoricas y Aplicadas (INIFTA), Facultad de Ciencias Exactas, UNLP, CONICET, Suc. 4, C.C. 16 (1900) La Plata (Argentina)]. E-mail: ealbano@inifta.unlp.edu.ar

    2004-11-22

    Based on the fact that, a standard prey-predator model (SPPM), exhibits irreversible phase transitions, belonging to the universality class of directed percolation (DP), between prey-predator coexistence and predator extinction [Phys. Lett. A 280 (2001) 45], a self-organized prey-predator model (SOPPM) is formulated and studied by means of extensive Monte Carlo simulations. The SOPPM is achieved defining the parameters of the SPPM as functions of the density of species. It is shown that the SOPPM self-organizes into an active state close the absorbing phase of the SPPM, and consequently their avalanche exponents also belong to the universality class of DP.

  7. Cannibalism in discrete-time predator-prey systems.

    Science.gov (United States)

    Chow, Yunshyong; Jang, Sophia R-J

    2012-01-01

    In this study, we propose and investigate a two-stage population model with cannibalism. It is shown that cannibalism can destabilize and lower the magnitude of the interior steady state. However, it is proved that cannibalism has no effect on the persistence of the population. Based on this model, we study two systems of predator-prey interactions where the prey population is cannibalistic. A sufficient condition based on the nontrivial boundary steady state for which both populations can coexist is derived. It is found via numerical simulations that introduction of the predator population may either stabilize or destabilize the prey dynamics, depending on cannibalism coefficients and other vital parameters.

  8. The Neuronal Control of Flying Prey Interception in Dragonflies

    Science.gov (United States)

    2014-08-19

    AFRL-OSR-VA-TR-2014-0193 THE NEURONAL CONTROL OF FLYING PREY INTERCEPTION IN DRAGONFLIES Robert Olberg TRUSTEES OF UNION COLLEGE IN THE TOWN OF...OMB control number. 12-08-2014 Final 15-05-2010 to 14-05-2014 The neuronal control of flying prey interception in dragonflies FA9550-10-1-0472 Olberg...AFOSR/PKR1 DUNS143574726 Distribution A. Approved for public release Eight pairs of large descending visual neurons (TSDNs) control dragonfly prey

  9. Toxoplasmosis in prey species and consequences for prevalence in feral cats: not all prey species are equal.

    Science.gov (United States)

    Afonso, E; Thulliez, P; Pontier, D; Gilot-Fromont, E

    2007-12-01

    Toxoplasma gondii is largely transmitted to definitive felid hosts through predation. Not all prey species represent identical risks of infection for cats because of differences in prey susceptibility, exposure and/or lifespan. Previously published studies have shown that prevalence in rodent and lagomorph species is positively correlated with body mass. We tested the hypothesis that different prey species have different infection risks by comparing infection dynamics of feral cats at 4 sites in the sub-Antarctic Kerguelen archipelago which differed in prey availability. Cats were trapped from 1994 to 2004 and anti-T. gondii IgG antibodies were detected using the modified agglutination test (> or =1:40). Overall seroprevalence was 51.09%. Antibody prevalence differed between sites, depending on diet and also on sex, after taking into account the effect of age. Males were more often infected than females and the difference between the sexes tended to be more pronounced in the site where more prey species were available. A difference in predation efficiency between male and female cats may explain this result. Overall, our results suggest that the composition of prey items in cat diet influences the risk of T. gondii infection. Prey compositon should therefore be considered important in any understanding of infection dynamics of T. gondii.

  10. Claviceps purpurea expressing polygalacturonases escaping PGIP inhibition fully infects PvPGIP2 wheat transgenic plants but its infection is delayed in wheat transgenic plants with increased level of pectin methyl esterification.

    Science.gov (United States)

    Volpi, Chiara; Raiola, Alessandro; Janni, Michela; Gordon, Anna; O'Sullivan, Donal M; Favaron, Francesco; D'Ovidio, Renato

    2013-12-01

    Claviceps purpurea is a biotrophic fungal pathogen of grasses causing the ergot disease. The infection process of C. purpurea on rye flowers is accompanied by pectin degradation and polygalacturonase (PG) activity represents a pathogenicity factor. Wheat is also infected by C. purpurea and we tested whether the presence of polygalacturonase inhibiting protein (PGIP) can affect pathogen infection and ergot disease development. Wheat transgenic plants expressing the bean PvPGIP2 did not show a clear reduction of disease symptoms when infected with C. purpurea. To ascertain the possible cause underlying this lack of improved resistance of PvPGIP2 plants, we expressed both polygalacturonases present in the C. purpurea genome, cppg1 and cppg2 in Pichia pastoris. In vitro assays using the heterologous expressed PGs and PvPGIP2 showed that neither PG is inhibited by this inhibitor. To further investigate the role of PG in the C. purpurea/wheat system, we demonstrated that the activity of both PGs of C. purpurea is reduced on highly methyl esterified pectin. Finally, we showed that this reduction in PG activity is relevant in planta, by inoculating with C. purpurea transgenic wheat plants overexpressing a pectin methyl esterase inhibitor (PMEI) and showing a high degree of pectin methyl esterification. We observed reduced disease symptoms in the transgenic line compared with null controls. Together, these results highlight the importance of pectin degradation for ergot disease development in wheat and sustain the notion that inhibition of pectin degradation may represent a possible route to control of ergot in cereals.

  11. Trophic relay and prey switching - A stomach contents and calorimetric investigation of an ambassid fish and their saltmarsh prey

    Science.gov (United States)

    McPhee, Jack J.; Platell, Margaret E.; Schreider, Maria J.

    2015-12-01

    Trophic relay is an ecological model that involves the movement of biomass and energy from vegetation, such as saltmarshes, within estuaries to the open sea via a series of predator-prey relationships. Any potential for trophic relay is therefore affected by water movements within an estuary and by the ability of a predator to "switch" prey in response to fluctuating abundances of those prey. Saltmarsh-dwelling grapsid crabs, which feed on saltmarsh-derived detritus and microphytobenthos, release zoeae into ebbing tides that inundate saltmarshes during spring-tide cycles within tidally-dominated estuaries, such as Brisbane Water Estuary, therefore providing an opportunity to examine whether prey-switching and/or trophic relay may occur in fish that feed on those zoeae (such as the highly abundant estuarine ambassid, Ambassis jacksoniensis). This model was examined by sampling A. jacksoniensis near saltmarshes in a large, temperate south-eastern Australian estuary during flood and ebb tides on days of saltmarsh inundation and non-inundation over four spring-tide events in 2012. Stomach fullnesses of A. jacksoniensis were generally highest during ebb tides on days of saltmarsh inundation, implying that feeding was most marked at these times. Caridean decapods dominated diets during flood tides and on days of no saltmarsh inundation, while crab zoeae dominated diets during ebb tides and on days of inundation, suggesting that, when saltmarsh-derived zoeae became abundant, A. jacksoniensis switched to feeding on those prey. Three potential zooplankton prey (calanoid copepods, caridean decapods and crab zoeae) did not differ calorimetrically, indicating that switching of prey by A. jacksoniensis is not directly related to their preying on energetically greater prey, but reflects opportunistic feeding on more abundant and/or less elusive prey. As A. jacksoniensis is able to switch prey from estuarine caridean decapods to saltmarsh-derived crab zoeae, this very abundant

  12. Harvesting Control for a Stage-Structured Predator-Prey Model with Ivlev's Functional Response and Impulsive Stocking on Prey

    Directory of Open Access Journals (Sweden)

    Kaiyuan Liu

    2007-01-01

    Full Text Available We investigate a delayed stage-structured Ivlev's functional response predator-prey model with impulsive stocking on prey and continuous harvesting on predator. Sufficient conditions of the global attractivity of predator-extinction periodic solution and the permanence of the system are obtained. These results show that the behavior of impulsive stocking on prey plays an important role for the permanence of the system. We also prove that all solutions of the system are uniformly ultimately bounded. Our results provide reliable tactical basis for the biological resource management and enrich the theory of impulsive delay differential equations.

  13. Perceiving the algae: How feeding-current feeding copepods detect their nonmotile prey

    DEFF Research Database (Denmark)

    Goncalves, Rodrigo J.; Kiørboe, Thomas

    2015-01-01

    Feeding-current feeding copepods detect and capture prey individually, but the mechanism by which nonmotile prey is detected has been unclear. Early reports that copepods detect phytoplankton prey at distances of one body length or more led to the hypothesis that solutes leaking from the prey wou...

  14. Foraging behavior of larval cod ( Gadus morhua ) influenced by prey density and hunger

    DEFF Research Database (Denmark)

    Munk, Peter

    1995-01-01

    to 7 mm long) was observed visually, and prey attacks, swimming activity and gut contents were registered across a range of 1 to 120 copepod nauplii l(-1). When prey density decreased, larvae increased their swimming activity, increased their responsiveness to prey (distance of reaction) and decreased...... in the lower range of (mean) prey densities measured at sea....

  15. Morphological and Genetic Variation along a North-to-South Transect in Stipa purpurea, a Dominant Grass on the Qinghai-Tibetan Plateau: Implications for Response to Climate Change.

    Science.gov (United States)

    Liu, Wensheng; Zhao, Yao; You, Jianling; Qi, Danhui; Zhou, Yin; Chen, Jiakuan; Song, Zhiping

    2016-01-01

    Estimating the potential of species to cope with rapid environmental climatic modifications is of vital importance for determining their future viability and conservation. The variation between existing populations along a climatic gradient may predict how a species will respond to future climate change. Stipa purpurea is a dominant grass species in the alpine steppe and meadow of the Qinghai-Tibetan Plateau (QTP). Ecological niche modelling was applied to S. purpurea, and its distribution was found to be most strongly correlated with the annual precipitation and the mean temperature of the warmest quarter. We established a north-to-south transect over 2000 km long on the QTP reflecting the gradients of temperature and precipitation, and then we estimated the morphological by sampling fruited tussocks and genetic divergence by using 11 microsatellite markers between 20 populations along the transect. Reproductive traits (the number of seeds and reproductive shoots), the reproductive-vegetative growth ratio and the length of roots in the S. purpurea populations varied significantly with climate variables. S. purpurea has high genetic diversity (He = 0.585), a large effective population size (Ne >1,000), and a considerable level of gene flow between populations. The S. purpurea populations have a mosaic genetic structure: some distant populations (over 1000 km apart) clustered genetically, whereas closer populations (transect and might be mediated by seed dispersal via migratory herbivores, such as the chiru (Pantholops hodgsonii). These findings suggest that population performance variation and gene flow both facilitate the response of S. purpurea to climate change.

  16. Estimulación de cardenólidos en brotes de Digitalis purpurea L. cultivados in vitro mediante elicitores

    Directory of Open Access Journals (Sweden)

    Naivy Lisbet Pérez-Alonso

    2014-06-01

    Full Text Available Título en ingles: Stimulation of cardenolides production in Digitalis purpurea L. shoot cultures by elicitors additionTítulo corto: Elicitores en la producción de cardenólidosResumen: Digitalis purpurea L. es una de las principales fuentes de cardenólidos tales como digoxina y digitoxina. Estos fármacos son ampliamente usados en la disfunción cardíaca y para regular las arritmias del corazón. El presente trabajo se realizó con el objetivo de estudiar el efecto de tres elicitores en el cultivo de brotes de Digitalis purpurea var. Roter Berggold para incrementar la producción in vitro de cardenólidos. La elicitación es una estrategia para incrementar la producción de biomasa y metabolitos secundarios en el cultivo in vitro. Los elicitores evaluados fueron ChitoPlant (0,001; 0,01; 0,1 g.L-1; SilioPlant (0,01; 0,1; 1,0 g.L-1 y Jasmonato de metilo (60, 80 y 100 µM, descritos por primera vez para el incremento de cardenólidos. Se demostró que la elicitación es una estrategia viable para el incremento de cardenólidos en brotes de D. purpurea. El ChitoPlant®, redujo la altura sin afectación en el resto de las variables morfológicas evaluadas. Además indujo un incremento significativo en el contenido de cardenólidos. El SilioPlant® (0,01 g.L-1 no provocó afectaciones en la biomasa e incrementó significativamente la síntesis de cardenólidos en los brotes en 3,6 y 6,9 veces el contenido de digoxina y digitoxina respectivamente. La elicitación con el jasmonato de metilo provocó una reducción de la biomasa. Los contenidos de digoxina y digitoxina se incrementaron ligera y significativamente con 80 y 100 µM de jasmonato de metilo respectivamente. El mejor resultado integral se obtuvo con 0,01 g.L-1 de SilioPlant, el cual indujo la mayor producción neta de cardenólidos por frasco de cultivo (4,72 µg digoxina y 88,27 µg digitoxina. Palabras clave: chitoplant, digitoxina, digoxina, jasmonato de metilo, silioplantAbstract:

  17. Predation and prey selectivity by Argyrosomus h%/epidotus ...

    African Journals Online (AJOL)

    ly show that larger prey are preferred by larger predators. S. Afr. J. Zoot. 1985 ... found in estuaries in Natal and the Cape (Wallace & van der. Elst 1975 .... Trawling depths and times ...... plankton picker, A. hololepidotus is probably an active.

  18. NONLINEAR SINGULARLY PERTURBED PREDATOR-PREY REACTION DIFFUSION SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    MoJiaqi; TangRongrong

    2004-01-01

    A class of nonlinear predator-prey reaction diffusion systems for singularly perturbedproblems are considered. Under suitable conditions, by using theory of differential inequalitiesthe existence and asymptotic behavior of solution for initial boundary value problems arestudied.

  19. Coexistence of structured populations with size-based prey selection

    DEFF Research Database (Denmark)

    Hartvig, Martin; Andersen, Ken Haste

    2013-01-01

    Abstract Species with a large adult-offspring size ratio and a preferred predator–prey mass ratio undergo ontogenetic trophic niche shift(s) throughout life. Trophic interactions between such species vary throughout life, resulting in different species-level interaction motifs depending on the ma......Abstract Species with a large adult-offspring size ratio and a preferred predator–prey mass ratio undergo ontogenetic trophic niche shift(s) throughout life. Trophic interactions between such species vary throughout life, resulting in different species-level interaction motifs depending...... coexistence’ state when the ratio between sizes at maturation of the two species is less than a predator–prey mass ratio and the resource level is low to intermediate, or in a ‘trophic ladder’ state if the ratio of sizes at maturation is larger than the predator–prey mass ratio at all resource levels. While...

  20. Scaling up predator–prey dynamics using spatial moment equations

    National Research Council Canada - National Science Library

    Barraquand, Frédéric; Murrell, David J; Spencer, Matthew

    2013-01-01

    Classical models of predator–prey dynamics, commonly used in community and evolutionary ecology to explain population cycles, species coexistence, the effects of enrichment, or predict the evolution of behavioural traits...

  1. Analyses of stomach contents provide information on prey of ...

    African Journals Online (AJOL)

    spamer

    However, this difficulty has been overcome for some localities .... Changes in prey choice with growth were investigated, ..... hunting behaviour and habitat use by the different sharks. ... doubt partly because of the resistance of the chitinous.

  2. The effect of standardized Echinacea purpurea extract on rat cytochrome P450 expression level.

    Science.gov (United States)

    Mrozikiewicz, P M; Bogacz, A; Karasiewicz, M; Mikolajczak, P L; Ozarowski, M; Seremak-Mrozikiewicz, A; Czerny, B; Bobkiewicz-Kozlowska, T; Grzeskowiak, E

    2010-08-01

    It is claimed that application of botanical supplements or herbal medicinal products with synthetic drugs that are cytochrome P450 enzymes substrates may induce significant herb-drug interactions and may alter pharmacotherapy. Echinacea preparations are one of the best selling products in the Europe and their medicinal use is still increasing but data about interactions of Echinacea extract with CYP enzymes are limited. In this study, we have investigated potential influence of standardized Echinacea purpurea extract containing 3.7% polyphenolic compounds on the mRNA expression level of major CYP450 enzymes using animal model. Total RNA was isolated from the rat liver tissue according to the manufacturer's protocol. Complementary DNA was synthesized from a mature mRNA template using reverse transcription. The level of mRNA expression in liver was analyzed by real-time quantitative PCR using specific target primers for CYP450 genes. In this study, it was demonstrated a significant increase of rat CYP2D1 and CYP1A1 expression level by 40% (p = 0.007) and 80% (p = 0.01), respectively. A weak inductory effect of the extract was observed for CYP1A2 by 16% (p > 0.05) compared with the control group. The levels of rat CYP3A1 and CYP3A2 mRNA were reduced by 41% (p Echinacea ethanolic extract. CYP2D2 and CYP2C6 activities were also inhibited by extract but in a lesser degree than CYP3A1 activity. Moreover, very little or no inhibition was noted for CYP2E1 both after 3 and 10 days of treatment. Our in vivo data indicate that the Echinacea ethanolic extract can potently inhibit the expression of CYP3A1/2 and can also induce of CYP1A1, CYP2D1. These findings suggest that Echinacea extract may influence the P450-mediated metabolism of different drugs and may initiate chemical carcinogenesis by activation of some compounds to their carcinogenic metabolites. 2010 Elsevier GmbH. All rights reserved.

  3. Determination of the Annual Shading Potential of Salix Purpurea Coppice using Hemispherical Photographs

    Science.gov (United States)

    Holzapfel, G.; Weihs, P.; Stockreiter, L.; Hoffmann, E.

    2012-04-01

    densities in terms of Leaf Area Index (LAI) and the corresponding incident solar radiation energy reaching a shaded water surface (Global Site Factor). Responding to these questions a two year old natural stand of Salix purpurea was monitored. The growth of riparian vegetation and the correlation to solar transmission during different phenological phases are measured periodically with radiation sensors. LAI is investigated using hemispherical photographs. Analysis is done with the software Hemiview and Gap Light Analyser (GLA). Results show discrepancies between analysis with the software programs and measurements. Altogether, the variability and the trends of both are similar: the same daily and annual changes can be seen.

  4. Molecular basis for prey relocation in viperid snakes

    Science.gov (United States)

    2013-01-01

    Background Vertebrate predators use a broad arsenal of behaviors and weaponry for overcoming fractious and potentially dangerous prey. A unique array of predatory strategies occur among snakes, ranging from mechanical modes of constriction and jaw-holding in non-venomous snakes, to a chemical means, venom, for quickly dispatching prey. However, even among venomous snakes, different prey handling strategies are utilized, varying from the strike-and-hold behaviors exhibited by highly toxic elapid snakes to the rapid strike-and-release envenomation seen in viperid snakes. For vipers, this mode of envenomation represents a minimal risk predatory strategy by permitting little contact with or retaliation from prey, but it adds the additional task of relocating envenomated prey which has wandered from the attack site. This task is further confounded by trails of other unstruck conspecific or heterospecific prey. Despite decades of behavioral study, researchers still do not know the molecular mechanism which allows for prey relocation. Results During behavioral discrimination trials (vomeronasal responsiveness) to euthanized mice injected with size-fractionated venom, Crotalus atrox responded significantly to only one protein peak. Assays for enzymes common in rattlesnake venoms, such as exonuclease, L-amino acid oxidase, metalloproteinase, thrombin-like and kallikrein-like serine proteases and phospholipase A2, showed that vomeronasal responsiveness was not dependent on enzymatic activity. Using mass spectrometry and N-terminal sequencing, we identified the proteins responsible for envenomated prey discrimination as the non-enzymatic disintegrins crotatroxin 1 and 2. Our results demonstrate a novel and critical biological role for venom disintegrins far beyond their well-established role in disruption of cell-cell and cell-extracellular matrix interactions. Conclusions These findings reveal the evolutionary significance of free disintegrins in venoms as the molecular

  5. Red queen dynamics in specific predator-prey systems.

    Science.gov (United States)

    Harris, Terence; Cai, Anna Q

    2015-10-01

    The dynamics of a predator-prey system are studied, with a comparison of discrete and continuous strategy spaces. For a [Formula: see text] system, the average strategies used in the discrete and continuous case are shown to be the same. It is further shown that the inclusion of constant prey switching in the discrete case can have a stabilising effect and reduce the number of available predator types through extinction.

  6. Recognition of inconspicuous prey: importance of additional visual cues

    OpenAIRE

    KARLÍKOVÁ, Zuzana

    2012-01-01

    The ability of wild caught great tits (Parus major) to discriminate between equally coloured edible (roach - Blaptica dubia) and inedible prey (firebug - Pyrrhocoris apterus) was tested with respect to other visual traits (shape of legs, antennae,means of locomotion). To simulate more natural conditions, three different experiment types were carried out. Prey was presented either alternately (first roach or firebug) or simultaneously. Additionally, the effect of learning and memory was tested...

  7. Feeding, prey selection and prey encounter mechanisms in the heterotrophic dinoflagellate Noctiluca scintillans

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; Titelman, J.

    1998-01-01

    (similar to 1 m h(- 1)). In stagnant water, clearance rates of latex spheres (5-80 mu m) increased approximately with prey particle size squared. This scaling is consistent with N.scintillans being an interception feeder. However, absolute clearance rates were substantially lower than those predicted...... higher rates than latex beads and other phytoplankters, particularly dinoflagellates. We propose that diatoms stick more efficiently than latex beads to the mucus of N.scintillans and that dinoflagellates reduce fatal contact behaviorally. We conclude that N.scintillans is an interception feeder...

  8. Local Bifurcations and Optimal Theory in a Delayed Predator-Prey Model with Threshold Prey Harvesting

    Science.gov (United States)

    Tankam, Israel; Tchinda Mouofo, Plaire; Mendy, Abdoulaye; Lam, Mountaga; Tewa, Jean Jules; Bowong, Samuel

    2015-06-01

    We investigate the effects of time delay and piecewise-linear threshold policy harvesting for a delayed predator-prey model. It is the first time that Holling response function of type III and the present threshold policy harvesting are associated with time delay. The trajectories of our delayed system are bounded; the stability of each equilibrium is analyzed with and without delay; there are local bifurcations as saddle-node bifurcation and Hopf bifurcation; optimal harvesting is also investigated. Numerical simulations are provided in order to illustrate each result.

  9. Síndrome distérmica (hipertermia em bovinos associada à intoxicação por Claviceps purpurea

    Directory of Open Access Journals (Sweden)

    Ilha Marcia R. S.

    2001-01-01

    Full Text Available Descrevem-se três surtos de síndrome distérmica (hipertermia associada à intoxicação por Claviceps purpurea, em bovinos de leite durante o verão de 1999-2000, em três estabelecimentos do Rio Grande do Sul. De um total de 66 bovinos que ingeriram a ração contaminada com o fungo, 37 (56% adoeceram até 3 meses após a introdução da ração contaminada. Os principais sinais clínicos foram temperatura retal elevada, pêlos compridos, longos e sem brilho, salivação intensa, respiração ofegante, com a boca aberta e, em alguns casos, com a língua para fora da cavidade oral. Os animais acometidos procuravam sombra ou permaneciam dentro d'água. Houve diminuição de 10 a 30% no consumo de alimentos e perda de peso. A redução na produção de leite foi de 30 a 50%. Os sinais clínicos se intensificavam durante o dia e eram diretamente proporcionais à elevação da temperatura ambiental. Os achados de necropsia em um bovino que foi eutanasiado, incluíram leve enfisema pulmonar, principalmente na região dorsal dos lobos pulmonares diafragmáticos. Histologicamente havia moderada hipertrofia da musculatura lisa dos bronquíolos e ruptura de septos alveolares formando cotos alveolares em clava. Nos três estabelecimentos onde ocorreram os surtos, escleródios de C. purpurea foram observados nas amostras de ração fornecida aos bovinos. Os animais afetados recuperaram-se após aproximadamente 60 dias da retirada da ração contaminada. O diagnóstico baseou-se em dados epidemiológicos, sinais clínicos, na presença de escleródios de C. purpurea na ração fornecida aos animais, nos achados de necropsia e na histopatologia. A patogenia e o quadro clínico-patológico observados são discutidos e comparados com outros relatos dessa enfermidade.

  10. Integrated pest management with stochastic birth rate for prey species.

    Science.gov (United States)

    Akman, Olcay; Comar, Timothy D; Hrozencik, Daniel

    2013-01-01

    Song and Xiang (2006) developed an impulsive differential equations model for a two-prey one-predator model with stage structure for the predator. They demonstrate the conditions on the impulsive period for which a globally asymptotically stable pest-eradication periodic solution exists, as well as conditions on the impulsive period for which the prey species is permanently maintained under an economically acceptable threshold. We extend their model by including stage structure for both predator and prey as well as by adding stochastic elements in the birth rate of the prey. As in Song and Xiang (2006), we find the conditions under which a globally asymptotically stable pest eradication periodic solution exists. In addition, we numerically show the relationship between the stochastically varying birth rate of the prey and the necessary efficacy of the pesticide for which the probability of eradication of the prey species is above 90%. This is significant because the model recognizes varying environmental and climatic conditions which affect the resources needed for pest eradication.

  11. Predator-prey interactions and changing environments: who benefits?

    Science.gov (United States)

    Abrahams, Mark V; Mangel, Marc; Hedges, Kevin

    2007-11-29

    While aquatic environments have long been thought to be more moderate environments than their terrestrial cousins, environmental data demonstrate that for some systems this is not so. Numerous important environmental parameters can fluctuate dramatically, notably dissolved oxygen, turbidity and temperature. The roles of dissolved oxygen and turbidity on predator-prey interactions have been discussed in detail elsewhere within this issue and will be considered only briefly here. Here, we will focus primarily on the role of temperature and its potential impact upon predator-prey interactions. Two key properties are of particular note. For temperate aquatic ecosystems, all piscine and invertebrate piscivores and their prey are ectothermic. They will therefore be subject to energetic demands that are significantly affected by environmental temperature. Furthermore, the physical properties of water, particularly its high thermal conductivity, mean that thermal microenvironments will not exist so that fine-scale habitat movements will not be an option for dealing with changing water temperature in lentic environments. Unfortunately, there has been little experimental analysis of the role of temperature on such predator-prey interactions, so we will instead focus on theoretical work, indicating that potential implications associated with thermal change are unlikely to be straightforward and may present a greater threat to predators than to their prey. Specifically, we demonstrate that changes in the thermal environment can result in a net benefit to cold-adapted species through the mechanism of predator-prey interactions.

  12. Predator interference and stability of predator-prey dynamics.

    Science.gov (United States)

    Přibylová, Lenka; Berec, Luděk

    2015-08-01

    Predator interference, that is, a decline in the per predator consumption rate as predator density increases, is generally thought to promote predator-prey stability. Indeed, this has been demonstrated in many theoretical studies on predator-prey dynamics. In virtually all of these studies, the stabilization role is demonstrated as a weakening of the paradox of enrichment. With predator interference, stable limit cycles that appear as a result of environmental enrichment occur for higher values of the environmental carrying capacity of prey, and even a complete absence of the limit cycles can happen. Here we study predator-prey dynamics using the Rosenzweig-MacArthur-like model in which the Holling type II functional response has been replaced by a predator-dependent family which generalizes many of the commonly used descriptions of predator interference. By means of a bifurcation analysis we show that sufficiently strong predator interference may bring about another stabilizing mechanism. In particular, hysteresis combined with (dis)appearance of stable limit cycles imply abrupt increases in both the prey and predator densities and enhanced persistence and resilience of the predator-prey system. We encourage refitting the previously collected data on predator consumption rates as well as for conducting further predation experiments to see what functional response from the explored family is the most appropriate.

  13. Indirect evolutionary rescue: prey adapts, predator avoids extinction.

    Science.gov (United States)

    Yamamichi, Masato; Miner, Brooks E

    2015-09-01

    Recent studies have increasingly recognized evolutionary rescue (adaptive evolution that prevents extinction following environmental change) as an important process in evolutionary biology and conservation science. Researchers have concentrated on single species living in isolation, but populations in nature exist within communities of interacting species, so evolutionary rescue should also be investigated in a multispecies context. We argue that the persistence or extinction of a focal species can be determined solely by evolutionary change in an interacting species. We demonstrate that prey adaptive evolution can prevent predator extinction in two-species predator-prey models, and we derive the conditions under which this indirect evolutionary interaction is essential to prevent extinction following environmental change. A nonevolving predator can be rescued from extinction by adaptive evolution of its prey due to a trade-off for the prey between defense against predation and population growth rate. As prey typically have larger populations and shorter generations than their predators, prey evolution can be rapid and have profound effects on predator population dynamics. We suggest that this process, which we term 'indirect evolutionary rescue', has the potential to be critically important to the ecological and evolutionary responses of populations and communities to dramatic environmental change.

  14. Efeito do período de chuva no controle de Euphorbia heterophylla e Ipomoea purpurea pelos herbicidas glyphosate e sulfosate Effect of rainfall on Euphorbia heterophylla and Ipomoea purpurea control by glyphosate and sulfosate

    Directory of Open Access Journals (Sweden)

    P.A. Monquero

    2007-01-01

    Full Text Available Avaliou-se a influência do período de chuva sobre a eficácia dos herbicidas sulfosate e glyphosate no controle de Euphorbia heterophylla e Ipomoea purpurea. O experimento foi instalado em casa de vegetação, no Centro de Ciências Agrárias/UFSCar, em Araras, SP. Os tratamentos, além da testemunha, consistiram na aplicação de duas doses em equivalente ácido dos herbicidas sulfosate (0,66 e 1,32 kg ha-1 e glyphosate (0,72 e 1,44 kg ha-1, sendo as plantas tratadas submetidas à simulação de chuva de 20 mm durante 30 minutos, nos intervalos de 2, 4, 6, 8 e 48 horas após a aplicação. O delineamento experimental utilizado foi o inteiramente casualizado, com quatro repetições. A eficácia no controle das plantas daninhas foi avaliada 7, 14 e 21 dias após a aplicação dos tratamentos (DAT e a matéria seca, aos 28 DAT. E. heterophylla não foi eficazmente controlada pelo herbicida glyphosate, exigindo intervalo sem chuva superior a 24 horas após a aplicação para obter, na maior dose, controle de apenas 60%. Por sua vez, o herbicida sulfosate proporcionou controle de 75%, mesmo na menor dose, quando a chuva ocorreu quatro horas depois da aplicação. I. purpurea também não foi controlada de maneira eficaz pelo herbicida glyphosate, independentemente da dose e do intervalo de chuva; no entanto, somente a maior dose do herbicida sulfosate foi eficiente no controle desta espécie, a partir de quatro horas sem chuva. Para ambas as espécies, o herbicida sulfosate foi menos afetado pelo período da chuva.The influence of rainfall occurrence was evaluated on the efficacy of the herbicides glyphosate and sulfosate applied in post-emergence on Euphorbia heterophylla and Ipomoea purpurea. The experiment was conducted under greenhouse conditions at the Centro de Ciências Agrárias/UFSCar, in Araras-SP, Brazil. The treatments,plus control, consisted of two doses, in acid equivalent of sulfosate (0.66 and 1.32 kg ha-1 and glyphosate (0.72 and

  15. Revealing the role of predator interference in a predator-prey system with disease in prey population

    DEFF Research Database (Denmark)

    Chakraborty, Subhendu; Kooi, B.W.; Biswas, B.

    2015-01-01

    on infected populations can have both positive and negative influences on disease in prey populations. Here, we present a predator-prey system where the prey population is subjected to an infectious disease to explore the impact of predator on disease dynamics. Specifically, we investigate how...... the interference among predators affects the dynamics and structure of the predator-prey community. We perform a detailed numerical bifurcation analysis and find an unusually large variety of complex dynamics, such as, bistability, torus and chaos, in the presence of predators. We show that, depending...... on the strength of interference among predators, predators enhance or control disease outbreaks and population persistence. Moreover, the presence of multistable regimes makes the system very sensitive to perturbations and facilitates a number of regime shifts. Since, the habitat structure and the choice...

  16. The Dynamical Analysis of a Prey-Predator Model with a Refuge-Stage Structure Prey Population

    Directory of Open Access Journals (Sweden)

    Raid Kamel Naji

    2016-01-01

    Full Text Available We proposed and analyzed a mathematical model dealing with two species of prey-predator system. It is assumed that the prey is a stage structure population consisting of two compartments known as immature prey and mature prey. It has a refuge capability as a defensive property against the predation. The existence, uniqueness, and boundedness of the solution of the proposed model are discussed. All the feasible equilibrium points are determined. The local and global stability analysis of them are investigated. The occurrence of local bifurcation (such as saddle node, transcritical, and pitchfork near each of the equilibrium points is studied. Finally, numerical simulations are given to support the analytic results.

  17. Dynamic Analysis of a Predator-Prey (Pest Model with Disease in Prey and Involving an Impulsive Control Strategy

    Directory of Open Access Journals (Sweden)

    Min Zhao

    2012-01-01

    Full Text Available The dynamic behaviors of a predator-prey (pest model with disease in prey and involving an impulsive control strategy to release infected prey at fixed times are investigated for the purpose of integrated pest management. Mathematical theoretical works have been pursuing the investigation of the local asymptotical stability and global attractivity for the semitrivial periodic solution and population persistent, which depicts the threshold expression of some critical parameters for carrying out integrated pest management. Numerical analysis indicates that the impulsive control strategy has a strong effect on the dynamical complexity and population persistent using bifurcation diagrams and power spectra diagrams. These results show that if the release amount of infective prey can satisfy some critical conditions, then all biological populations will coexist. All these results are expected to be of use in the study of the dynamic complexity of ecosystems.

  18. Prey utilization by wolves and a preliminary assessment of wolf and prey densities in three drainages within the Arctic National Wildlife Refuge, Alaska

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report covers the prey utilization by wolves and an assessment of wolf and prey densities in 3 drainages within the Arctic National Wildlife Refuge. The...

  19. A specialized araneophagic predator's short-term nutrient utilization depends on the macronutrient content of prey rather than on prey taxonomic affiliation

    DEFF Research Database (Denmark)

    Toft, Søren; Li, Daiqin; Mayntz, David

    2010-01-01

    A specialist predator that has a specialized diet, prey-specific prey-capture behaviour and a preference for a particular type of prey may or may not be specialized metabolically. Previous studies have shown that jumping spiders of the genus Portia prey on other spiders using prey-specific prey......-capture behaviour, prefer spiders as prey to insects and gain long-term benefits in terms of higher survival and growth rates on spider diets than on insect diets. However, it is unclear whether there are substances uniquely present in spiders on which Portia depends, or, alternatively, spiders and insects all...... contain more or less the same nutrients but the relative amounts of these substances are such that Portia perform better on a spider diet. These questions are addressed by testing the hypothesis that prey specialization includes metabolic adaptations that allow Portia an enhanced nutrient extraction...

  20. Dynamics and patterns of a diffusive Leslie-Gower prey-predator model with strong Allee effect in prey

    Science.gov (United States)

    Ni, Wenjie; Wang, Mingxin

    2016-10-01

    This paper is devoted to study the dynamical properties and stationary patterns of a diffusive Leslie-Gower prey-predator model with strong Allee effect in the prey population. We first analyze the nonnegative constant equilibrium solutions and their stabilities, and then study the dynamical properties of time-dependent solutions. Moreover, we investigate the stationary patterns induced by diffusions (Turing pattern). Our results show that the impact of the strong Allee effect essentially increases the system spatiotemporal complexity.

  1. Dynamic Behaviors of a Nonautonomous Discrete Predator-Prey System Incorporating a Prey Refuge and Holling Type II Functional Response

    Directory of Open Access Journals (Sweden)

    Yumin Wu

    2012-01-01

    Full Text Available A nonautonomous discrete predator-prey system incorporating a prey refuge and Holling type II functional response is studied in this paper. A set of sufficient conditions which guarantee the persistence and global stability of the system are obtained, respectively. Our results show that if refuge is large enough then predator species will be driven to extinction due to the lack of enough food. Two examples together with their numerical simulations show the feasibility of the main results.

  2. Comparing nearshore benthic and pelagic prey as mercury sources to lake fish: the importance of prey quality and mercury content.

    Science.gov (United States)

    Karimi, Roxanne; Chen, Celia Y; Folt, Carol L

    2016-09-15

    Mercury (Hg) bioaccumulation in fish poses well-known health risks to wildlife and humans through fish consumption. Yet fish Hg concentrations are highly variable, and key factors driving this variability remain unclear. One little studied source of variation is the influence of habitat-specific feeding on Hg accumulation in lake fish. However, this is likely important because most lake fish feed in multiple habitats during their lives, and the Hg and caloric content of prey from different habitats can differ. This study used a three-pronged approach to investigate the extent to which habitat-specific prey determine differences in Hg bioaccumulation in fish. This study first compared Hg concentrations in common nearshore benthic invertebrates and pelagic zooplankton across five lakes and over the summer season in one lake, and found that pelagic zooplankton generally had higher Hg concentrations than most benthic taxa across lakes, and over a season in one lake. Second, using a bioenergetics model, the effects of prey caloric content from habitat-specific diets on fish growth and Hg accumulation were calculated. This model predicted that the consumption of benthic prey results in lower fish Hg concentrations due to higher prey caloric content and growth dilution (high weight gain relative to Hg from food), in addition to lower prey Hg levels. Third, using data from the literature, links between fish Hg content and the degree of benthivory, were examined, and showed that benthivory was associated with reduced Hg concentrations in lake fish. Taken together, these findings support the hypothesis that higher Hg content and lower caloric content make pelagic zooplankton prey greater sources of Hg for fish than nearshore benthic prey in lakes. Hence, habitat-specific foraging is likely to be a strong driver of variation in Hg levels within and between fish species.

  3. Delayed stage-structured predator-prey model with impulsive perturbations on predator and chemical control on prey

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    We consider a delayed stage-structured pest management predator-prey system with impulsive transmitting on predator and chemical control on prey. Sufficient conditions of the global attractiveness of the pest-extinction boundary periodic solution and permanence of the system are obtained. We also prove that all solutions of the system are uniformly ultimately bounded. Our results provide reliable tactical basis for practical pest management.

  4. STABILITY OF A PREDATOR-PREY SYSTEM WITH PREY TAXIS IN A GENERAL CLASS OF FUNCTIONAL RESPONSES

    Institute of Scientific and Technical Information of China (English)

    M.YOUSEFNEZHAD; S.A. MOHAMMADI

    2016-01-01

    In this paper, a diffusive predator-prey system with general functional responses and prey-tactic sensitivities is studied. Providing such generality, we construct a Lyapunov function and we show that the positive constant steady state is locally and globally asymp-totically stable. With an eye on the biological interpretations, a numerical simulation is performed to illustrate the feasibility of the analytical findings.

  5. Variable prey development time suppresses predator-prey cycles and enhances stability.

    Science.gov (United States)

    Cronin, James T; Reeve, John D; Xu, Dashun; Xiao, Mingqing; Stevens, Heidi N

    2016-03-01

    Although theoretical models have demonstrated that predator-prey population dynamics can depend critically on age (stage) structure and the duration and variability in development times of different life stages, experimental support for this theory is non-existent. We conducted an experiment with a host-parasitoid system to test the prediction that increased variability in the development time of the vulnerable host stage can promote interaction stability. Host-parasitoid microcosms were subjected to two treatments: Normal and High variance in the duration of the vulnerable host stage. In control and Normal-variance microcosms, hosts and parasitoids exhibited distinct population cycles. In contrast, insect abundances were 18-24% less variable in High- than Normal-variance microcosms. More significantly, periodicity in host-parasitoid population dynamics disappeared in the High-variance microcosms. Simulation models confirmed that stability in High-variance microcosms was sufficient to prevent extinction. We conclude that developmental variability is critical to predator-prey population dynamics and could be exploited in pest-management programs.

  6. AFSOC Urban Operations Training & Capabilities Final Environmental Assessment

    Science.gov (United States)

    2005-12-01

    flatwoods, and baygall communities throughout Eglin. ● Pineland Hoary Pea ( Tephrosia mohrii). The Pineland Hoary Pea, an herbaceous plant, is a...Purple pitcher plant (Sarracenia purpurea ). The purple pitcher plant is a native, carnivorous herb. In its southern distribution, this pitcher plant

  7. B61 Joint Test Assembly (JTA) Weapons Systems Evaluation Program (WSEP) Eglin Air Force Base, FL Final Environmental Assessment

    Science.gov (United States)

    2004-06-01

    Water Tupelo Nyssa biflora Five-lined Skink Eumeces fasciatus Pitcher Plant Sarracenis purpurea Green Anole Anolis carolinensis Red Titi Cyrilla...Unknown C-52C Lilium iridollae Panhandle lily SE C-52C Tephrosia mohrii Pineland Hoary Pea ST C-52C Sarracenia rubra Red-flowered Pitcher Plant SE C

  8. Copper and cadmium tolerance, uptake and effect on chloroplast ultrastructure. Studies on Salix purpurea and Phragmites australis

    Energy Technology Data Exchange (ETDEWEB)

    Hakmaoui, A.; Ater, A. [Abdelmalek Essaadi Univ., Tetouan (Morocco). Dept. of Biology; Boka, K. [Eoetvoes Lorand Univ., Budapest (Hungary). Dept. of Plant Anatomy; Baron, M. [Granada Univ. (Spain). Dept. of Biochemistry and Cell and Molecular Biology of Plants

    2007-05-15

    We have compared the effect of toxic Cu and Cd concentrations on growth, metal accumulation, and chloroplast ultrastructure of willow (Salix purpurea L.) and reed [Phragmites australis (Cav.) Trin. ex Steud.]. After a 10-day treatment, both species have tolerated to some extent the lowest concentration of both metals; however, plant growth was strongly reduced at the highest Cu and Cd concentrations. These plants could be described as Cu-tolerant at the lowest concentration tested, showing a higher tolerance index in reed than in willow; in contrast, willow exhibited higher tolerance against Cd. Both plants appeared to be moderate root accumulators of Cu and Cd. Ultrastructural studies revealed special features that can provide some protection against heavy metals stress, such as ferritin aggregates in the stroma. In addition, Cu and Cd induced distortion of thylakoids, reduction of grana stacks, as well as an increased number and size of plastoglobuli and peripheral vesicles. (orig.)

  9. Effects of Tephrosia purpurea aqueous seed extract on blood glucose and antioxidant enzyme activities in streptozotocin induced diabetic rats.

    Science.gov (United States)

    Pavana, P; Sethupathy, S; Santha, K; Manoharan, S

    2008-10-25

    The aim of the present study was to evaluate the effects of aqueous seed extract of Tephrosia purpurea (TpASet) on blood glucose and antioxidant status in streptozotocin induced diabetic rats. Hyperglycemia associated with an altered hexokinase and glucose-6-phosphatase activities, elevated lipid peroxidation, disturbed enzymatic [Superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx)] and non enzymatic [Glutathione, vitamin C and vitamin E] antioxidant status were observed in streptozotocin induced diabetic rats. Oral administration of "TpASet" at a dose of 600 mg/kg body weight showed significant improvement in above mentioned parameters. Our results clearly indicate that "TpASet" has potent antihyperglycemic and antioxidant effects in streptozotocin-induced diabetic rats and therefore further studies are warranted to isolate and characterize the bioactive principles from "TpASet".

  10. Activity-guided isolation of constituents of Tephrosia purpurea with the potential to induce the phase II enzyme, quinone reductase.

    Science.gov (United States)

    Chang, L C; Gerhäuser, C; Song, L; Farnsworth, N R; Pezzuto, J M; Kinghorn, A D

    1997-09-01

    An isoflavone, 7,4'-dihydroxy-3',5'-dimethoxyisoflavone (1), and a chalcone, (+)-tephropurpurin (2), both novel compounds, as well as six constituents of known structure, (+)-purpurin (3), pongamol (4), lanceolatin B (5), (-)-maackiain (6), (-)-3-hydroxy-4-methoxy-8,9-methylene-dioxypterocarpan (7), and (-)-medicarpin (8), were obtained as active compounds from Tephrosia purpurea, using a bioassay based on the induction of quinone reductase (QR) activity with cultured Hepa 1c1c7 mouse hepatoma cells. Additionally, three inactive compounds of known structure, 3'-methoxydaidzein, desmoxyphyllin B, and 3,9-dihydroxy-8-methoxycoumestan, were isolated and identified. The structure elucidation of compounds 1 and 2 was carried out by spectral data interpretation.

  11. Isomeric C12-alkamides isolated from purple coneflower (Echinacea purpurea (L.) Moench) exhibit characteristics of a PPARγ partial agonist

    DEFF Research Database (Denmark)

    El-Houri, Rime Bahij; Kotowska, Dorota; Wolber, Gerhard

    Nuclear hormone receptor PPARγ is predominantly found in adipose tissue and plays a role in regulating adipogenesis and glucose homeostasis. PPARγ belongs to the superfamily of transcription factors that bind DNA and regulate transcription in a ligand-dependent manner. A dichloromethane extract...... of Echinacea purpurea roots increasing glucose uptake (GU) and activating PPARγ was subjected to bioassay-guided chromatographic fractionation. Basal and insulin-dependent GU in 3T3-L1 adipocytes and PPARγ transactivation assay were used to assess the bioactivity of extract, fractions and isolated metabolites....... Two novel isomeric dodeca-2E,4E,8Z,10E/Z-tetraenoic acid 2-methylbutylamides together with two known C12-alkamides and -linolenic acid were isolated from active fractions. The compounds were found to activate PPARγ but only the isomeric alkamides were able to increase basal and insulin-dependent GU...

  12. Localization of ergot alkaloids in sclerotia of Claviceps purpurea by matrix-assisted laser desorption/ionization mass spectrometry imaging.

    Science.gov (United States)

    Dopstadt, Julian; Vens-Cappell, Simeon; Neubauer, Lisa; Tudzynski, Paul; Cramer, Benedikt; Dreisewerd, Klaus; Humpf, Hans-Ulrich

    2017-02-01

    The fungus Claviceps purpurea produces highly toxic ergot alkaloids and accumulates these in the hardened bodies of fungal mycelium. These so-called sclerotia, or ergot bodies, replace the crop seed of infected plants, which can include numerous important food- and feedstuff such as rye and wheat. While several studies have explored details of the infection process and development of ergot bodies, little information is available on the spatial distribution of the mycotoxins in the sclerotia. Here we used matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) at a lateral resolution of 35 μm to visualize the distribution of two representative alkaloids, ergocristine and ergometrine, produced by Ecc93 and Gal 310 variants of C. purpurea, respectively, after infection of rye. To improve cryosectioning of this fragile biological material tissue with complex texture, we developed a practical embedding protocol based on cellulose polymers. The MALDI-MS images recorded from the so produced intact tissues sections revealed that ergometrine exhibited a relatively homogeneous distribution throughout the ergot body, whereas ergocristine was found to be enriched in the proximal region. This finding can be correlated to the morphological development of sclerotia as ergot alkaloids are only produced in the sphacelial stage. The ability to localize toxins and other secondary metabolites in intact sections of crop-infecting fungi with high lateral resolution renders MALDI-MSI a powerful tool for investigating biosynthetic pathways and for obtaining a deeper understanding of the parasite-host interaction. Graphical abstract Workflow for identification and spatial localization of ergot alkaloids in infected rye grains.

  13. Phytopharmacologic preparations as predictors of plant bioactivity: A particular approach to Echinacea purpurea (L.) Moench antioxidant properties.

    Science.gov (United States)

    Pires, Cristiana; Martins, Natália; Carvalho, Ana Maria; Barros, Lillian; Ferreira, Isabel C F R

    2016-01-01

    A large body of evidence has confirmed a multitude of health benefits of plant products and their derived formulations. Echinacea purpurea (L.) Moench is a good example, widely used due to its therapeutic properties. In the present study, the chemical composition of the different samples and antioxidant properties of E. purpurea hydroethanolic and aqueous extracts obtained from dry or fresh raw material were evaluated and compared with dietary supplements based on the same plant (tablets and syrup), to determine the most active phytopharmacologic preparation or formulation. Chemical composition of the different samples was assessed through the determination of free sugars, organic acids and tocopherols. The in vitro antioxidant properties were determined using four assays: 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radicals scavenging activity, reducing power, inhibition of b-carotene bleaching and inhibition of lipid peroxidation by thiobarbituric acid reactive substances (TBARS) assay. Total phenolics and flavonoids were also determined. Overall, the hydroethanolic extract of fresh plant revealed the highest activity, directly related with its higher contents in phenolic (229.22 ± 4.38 mg gallic acid equivalent [GAE]/mL), flavonoids (124.83 ± 7.47 mg GAE/mL), organic acids (8.89 ± 0.10 g/100 g), and tocopherols (4.55 ± 0.02 mg/100 g). Tablets followed by syrup revealed the worst effect, positively correlated with the lowest abundance in bioactive molecules. The weak in vitro antioxidant potential of commercial phytopharmacologic formulations could be related to their chemical composition, including the addition of excipients. Further studies are necessary to deepen knowledge on this area, namely focusing on in vivo experiments, to establish upcoming guidelines to improve the quality and bioavailability of phytopharmacologic formulations. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Efficient counter-current chromatographic isolation and structural identification of two new cinnamic acids from Echinacea purpurea.

    Science.gov (United States)

    Lu, Ying; Li, JiaYin; Li, MiLu; Hu, Xia; Tan, Jun; Liu, Zhong Hua

    2012-10-01

    Two new cinnamic acids, 2-O-caffeoyl-3-O-isoferuloyltartaric (3), and 2, 3-di-O-isoferuloyltartaric acid (5), along with three known caffeic acids, cichoric acid (1), 2-O-caffeoyl-3-O-feruloyltartaric acid (2) and 2-O-caffeoyl-3-O-p-coumaroyltartaric acid (4), have been successfully isolated and purified from Echinacea purpurea. In this study, we investigated an efficient method for the preparative isolation and purification of cinnamic acids from E. purpurea by high-speed counter-current chromatography (HSCCC). The separation was performed using a two-phase solvent composed of n-hexane-ethyl-acetate-methanol-0.5% aqueous acetic acid (1:3:1:4, v/v). The upper phase was used as the stationary phase and the lower phase as the mobile phase, with a flow rate of 1.6 mL/min. From 250 mg of crude extracts, 65.1 mg of 1, 8.3 mg of 2, 4.0 mg of 3, 4.5 mg of 4, and 4.3 mg of 5 were isolated in one-step, with purities of 98.5%, 97.7%, 94.6%, 94.3%, and 98.6%, respectively, as evaluated by HPLC-DAD. The chemical structures were identified by electro spray ionization mass spectrometry (ESI-MS) and one- and two-dimensional NMR spectra. HSCCC was very efficient for the separation and purification of the cinnamic acids from

  15. A mast fruiting episode of the tropical tree Peltogyne purpurea(Caesalpinaceaein the Osa Peninsula, Costa Rica

    Directory of Open Access Journals (Sweden)

    Oscar J Rocha

    2006-12-01

    Full Text Available Se describe un episodio de fructificación en masa en una población de Peltogyne purpurea de la Península de Osa, Costa Rica. En febrero y marzo de 2000, la mayor parte de los árboles de esta especie tuvo una gran cosecha de frutos. En los años anteriores, desde 1995, ninguno o muy pocos árboles produjeron frutos y la producción por árbol fue escasa. La cosecha del año 2000 fue masiva y todos los árboles examinados produjeron frutos abundantes. Este patrón reproductivo podría producir extinciones locales si la extracción maderera no lo toma en cuentaThe existence of mast fruiting has not been well documented in the Neotropics. The occurrence of a mast fruiting episode in the population of the tree Peltogyne purpurea in the Osa Peninsula of Costa Rica is described. In February and March of 2000 most of the trees of this species produced a large fruit crop, compared with 1995-1999, when the number of fruit producing trees was very low or zero and those that did bear fruit, did so at a low intensity. In contrast, the fruit crop of 2000 was massive, all trees examined produced fruits and the intensity of fruiting was maximal. There is not enough information on the event for a hypothesis to be formed because the climatic or biological cues that triggered this sporadic flowering are unknown and there is no meteorological data available for this area. Populations with this mode of reproduction may experience local extinction bacause of logging operations. Rev. Biol. Trop. 54 (4: 1151-1155. Epub 2006 Dec. 15

  16. Do lions Panthera leo actively select prey or do prey preferences simply reflect chance responses via evolutionary adaptations to optimal foraging?

    Science.gov (United States)

    Hayward, Matt W; Hayward, Gina J; Tambling, Craig J; Kerley, Graham I H

    2011-01-01

    Research on coursing predators has revealed that actions throughout the predatory behavioral sequence (using encounter rate, hunting rate, and kill rate as proxy measures of decisions) drive observed prey preferences. We tested whether similar actions drive the observed prey preferences of a stalking predator, the African lion Panthera leo. We conducted two 96 hour, continuous follows of lions in Addo Elephant National Park seasonally from December 2003 until November 2005 (16 follows), and compared prey encounter rate with prey abundance, hunt rate with prey encounter rate, and kill rate with prey hunt rate for the major prey species in Addo using Jacobs' electivity index. We found that lions encountered preferred prey species far more frequently than expected based on their abundance, and they hunted these species more frequently than expected based on this higher encounter rate. Lions responded variably to non-preferred and avoided prey species throughout the predatory sequence, although they hunted avoided prey far less frequently than expected based on the number of encounters of them. We conclude that actions of lions throughout the predatory behavioural sequence, but particularly early on, drive the prey preferences that have been documented for this species. Once a hunt is initiated, evolutionary adaptations to the predator-prey interactions drive hunting success.

  17. Sea otter foraging behavior and hydrocarbon levels in prey

    Science.gov (United States)

    Doroff, Angela M.; Bodkin, James L.; Loughlin, Thomas R.

    1994-01-01

    Following the Exxon Valdez oil spill (EVOS), Prudhoe Bay crude oil from the vessel spread on the sea surface and covered coastal shores from western Prince William Sound (PWS) to the Alaska Peninsula. In PWS alone. acute mortality of sca otters at the time of the spill was estimated to be greater than 2000 (Doroff et al. 1993; Garrott et al. 1993).Shoreline oiling was observed on approximately 24% of the 1891 km of coastline surveyed within PWS (Exxon Valdez Oil Spill Damage Assessment Geoprocessing Group 1991). The effect of oil on the abundance of nearshore marine invertebrate populations is unclear, and the concentration and persistence of hydrocarbons present in tissues of most of these invertebrate species still remains unknown. What is known is that marine bivalves can accumulate petroleum hydrocarbons from both chronic and acute sources (Blumer et al. 1970; Ehrhardt 1972; Boehun and Quinn 1977). Potential long-term chronic effects of oiled intertidal and subtidal prey on the sea otter population are of concern.Sea otters prey on a wide variety of benthic marine invertebrates (Riedman and Estes 1990) and forage in shallow coastal waters (Wild and Arnes 1974), which vary widely in exposure to the open ocean, substrate type, and community composition. Sea otters have high metabolic demands relative to other marine mammals and can consume 20-25% of their body weight per day in invertebrate prey (Kenyon 1969: Costa and Kooyman 1984). Sca otters have occupied southwestern PWS since at least the early 1950s (Lensink 1962; Garshelis et al. 1986). The sea otter population in the PWS spill region was likely near equilibrium density and limited by prey availability before the oil spill (xcurrel (Estes et al. 1981; Garshelis et al. 1986; Johnson 1987). Sea otters in this region spent 59% of the daylight hours foraging, while otters in recently reoccupied habitats of eastern PWS spent only 27%. (Garshelis et al. 1986). Therefore, small differences in abundance of prey

  18. Prey type, vibrations and handling interactively influence spider silk expression.

    Science.gov (United States)

    Blamires, S J; Chao, I-C; Tso, I-M

    2010-11-15

    The chemical and mechanical properties of spider major ampullate (MA) silks vary in response to different prey, mostly via differential expression of two genes - MaSp1 and MaSp2 - although the spinning process exerts additional influence over the mechanical properties of silk. The prey cues that initiate differential gene expression are unknown. Prey nutrients, vibratory stimuli and handling have been suggested to be influential. We performed experiments to decouple the vibratory stimuli and handling associated with high and low kinetic energy prey (crickets vs flies) from their prey nutrients to test the relative influence of each as inducers of silk protein expression in the orb web spider Nephila pilipes. We found that the MA silks from spiders feeding on live crickets had greater percentages of glutamine, serine, alanine and glycine than those from spiders feeding on live flies. Proline composition of the silks was unaffected by feeding treatment. Increases in alanine and glycine in the MA silks of the live-cricket-feeding spiders indicate a probable increase in MaSp1 gene expression. The amino acid compositions of N. pilipes feeding on crickets with fly stimuli and N. pilipes feeding on flies with cricket stimuli did not differ from each other or from pre-treatment responses, so these feeding treatments did not induce differential MaSp expression. Our results indicate that cricket vibratory stimuli and handling interact with nutrients to induce N. pilipes to adjust their gene expression to produce webs with mechanical properties appropriate for the retention of this prey. This shows that spiders can genetically alter their silk chemical compositions and, presumably, mechanical properties upon exposure to different prey types. The lack of any change in proline composition with feeding treatment in N. pilipes suggests that the MaSp model determined for Nephila clavipes is not universally applicable to all Nephila.

  19. Research Progress of Introduced Echinacea purpurea%我国引种药用植物紫锥菊研究进展

    Institute of Scientific and Technical Information of China (English)

    韩琳娜; 周凤琴

    2012-01-01

    紫锥菊全草药用价值广泛,在欧美颇负盛名.上世纪90年代始引种我国.从栽培学、化学成分、质量评价和药理活性方面综述了紫锥菊引种至我国10余年来的研究成果,为紫锥菊在我国进一步的开发应用提供理论依据.%This article reviews the research of Echinacea purpurea introduced to China for more than ten years,including cultivation techniques, chemical composition, pharmacological activity and so on. It provides a theoretical basis for the development and application of Echinacea purpurea.

  20. EFFECTIVENESS OF THE DERYNG AND CLEVENGER-TYPE APPARATUS IN ISOLATION OF VARIOUS TYPES OF COMPONENTS OF ESSENTIAL OIL FROM THE MUTELINA PURPUREA THELL. FLOWERS.

    Science.gov (United States)

    Baj, Tomasz; Sieniawska, Elwira; Kowalski, Radoslaw; Wesolowskp, Marek; Ulewicz-Magulska, Beata

    2015-01-01

    In this study, both qualitative and quantitative analyses of chemical composition of M. purpurea essential oil obtained in the Deryng and Clevenger-type apparatuses were compared. As a result, content of volatile compounds were: 785.67 mg/mL and 833.33 mg/mL in the oil obtained in the Deryng (D-EO) and Clevenger-type apparatuses (C-EO), respectively. The major components of both essential oils from M. purpurea were: a-pinene, sabinene, myrcene, (Z)-sesquisabinene hydrate, (E)-sesquisabinene hydrate, and a-bis-abolol. The correlation coefficients values are not determined by the differences in the concentrations of the components resulting from the application of two different methods of distillation.

  1. Comparative growth and development of spiders reared on live and dead prey.

    Science.gov (United States)

    Peng, Yu; Zhang, Fan; Gui, Shaolan; Qiao, Huping; Hose, Grant C

    2013-01-01

    Scavenging (feeding on dead prey) has been demonstrated across a number of spider families, yet the implications of feeding on dead prey for the growth and development of individuals and population is unknown. In this study we compare the growth, development, and predatory activity of two species of spiders that were fed on live and dead prey. Pardosa astrigera (Lycosidae) and Hylyphantes graminicola (Lyniphiidae) were fed live or dead fruit flies, Drosophila melanogaster. The survival of P. astrigera and H. graminicola was not affected by prey type. The duration of late instars of P. astrigera fed dead prey were longer and mature spiders had less protein content than those fed live prey, whereas there were no differences in the rate of H. graminicola development, but the mass of mature spiders fed dead prey was greater than those fed live prey. Predation rates by P. astrigera did not differ between the two prey types, but H. graminicola had a higher rate of predation on dead than alive prey, presumably because the dead flies were easier to catch and handle. Overall, the growth, development and reproduction of H. graminicola reared with dead flies was better than those reared on live flies, yet for the larger P. astrigera, dead prey may suit smaller instars but mature spiders may be best maintained with live prey. We have clearly demonstrated that dead prey may be suitable for rearing spiders, although the success of the spiders fed such prey appears size- and species specific.

  2. Leaf metabolite profile of the Brazilian resurrection plant Barbacenia purpurea Hook. (Velloziaceae) shows two time-dependent responses during desiccation and recovering.

    Science.gov (United States)

    Suguiyama, Vanessa F; Silva, Emerson A; Meirelles, Sergio T; Centeno, Danilo C; Braga, Marcia R

    2014-01-01

    Barbacenia purpurea is a resurrection species endemic to rock outcrops, in Rio de Janeiro, Brazil. It tolerates great temperature variations, which are associated to periods of up to 30 days without precipitation. Using a metabolomic approach, we analyzed, under winter and summer conditions, changes in the leaf metabolite profile (MP) of potted plants of B. purpurea submitted to daily watered and water deficit for at least 20 days and subsequent slow rehydration for 5 days. Leaves were collected at different time points and had their MP analyzed by GC/MS, HPAEC, and UHPLC techniques, allowing the identification of more than 60 different compounds, including organic and amino acids, sugars, and polyols, among others. In the winter experiment, results suggest the presence of two time-dependent responses in B. purpurea under water stress. The first one starts with the increase in the content of caffeoyl-quinic acids, substances with strong antioxidant activity, until the 16th day of water suppression. When RWC reached less than 80 and 70%, in winter and summer respectively, it was observed an increase in polyols and monosaccharides, followed by an increment in the content of RFO, suggesting osmotic adjustment. Amino acids, such as GABA and asparagine, also increased due to 16 days of water suppression. During rehydration, the levels of the mentioned compounds became similar to those found at the beginning of the experiment and when compared to daily watered plants. We conclude that the tolerance of B. purpurea to dehydration involves the perception of water deficit intensity, which seems to result in different strategies to overcome the gradient of water availability imposed along a certain period of stress mainly during winter. Data from summer experiment indicate that the metabolism of B. pupurea was already primed for drought stress. The accumulation of phenolics in summer seemed to be more temperature and irradiance-dependent than on the RWC.

  3. The isolation and synthesis of a novel benzofuran compound from Tephrosia purpurea, and the synthesis of several related derivatives, which suppress histamine H1 receptor gene expression.

    Science.gov (United States)

    Shill, Manik Chandra; Das, Asish Kumar; Itou, Tomohiro; Karmakar, Sanmoy; Mukherjee, Pulok K; Mizuguchi, Hiroyuki; Kashiwada, Yoshiki; Fukui, Hiroyuki; Nemoto, Hisao

    2015-11-01

    A novel naturally occurring compound with a benzofuran skeleton was isolated from a plant, Tephrosia purpurea collected in Bangladesh. The chemical synthesis of this compound confirmed its structure, and preliminary biological results showed its suppressive activity towards histamine H1 gene expression. One isomer and four derivatives were also synthesized, and their suppression activity was investigated. Although only small quantities of this compound can be isolated from its natural source, a 10 g scale synthesis was demonstrated by the newly developed method.

  4. Effect of potassium chloride and phenyl mercuric acetate on the regulation of stomatal opening and water economy in Tephrosia purpurea Pers

    Energy Technology Data Exchange (ETDEWEB)

    Mathur, T.; Sen, D.N.

    1973-01-01

    Investigations were carried out on the effects of potassium chloride and phenylmercuric acetate on the plant Tephrosia purpurea. KCl and PMA were sprayed on the plants, and consequent water loss and leaf water content were measured at different time intervals. KCl treated plants lost more water than PMA treated ones; their stomata remained wide open. The percentage of absolute moisture remained higher in the PMA treated plants than in the KCl treated plants.

  5. Leaf metabolite profile of the Brazilian resurrection plant Barbacenia purpurea Hook. (Velloziaceae shows two time-dependent responses during desiccation and recovering

    Directory of Open Access Journals (Sweden)

    Vanessa Fuentes Suguiyama

    2014-03-01

    Full Text Available Barbacenia purpurea is a resurrection species endemic to rock outcrops, in Rio de Janeiro, Brazil. It tolerates great temperature variations, which are associated to periods of up to 30 days without precipitation. Using a metabolomic approach, we analyzed, under winter and summer conditions, changes in the leaf metabolite profile (MP of potted plants of B. purpurea submitted to daily watered and water deficit for at least 20 days and subsequent slow rehydration for 5 days. Leaves were collected at different time points and had their MP analyzed by GC/MS, HPAEC, and UHPLC techniques, allowing the identification of more than 60 different compounds, including organic and amino acids, sugars, and polyols, among others. In the winter experiment, results suggest the presence of two time-dependent responses in B. purpurea under water stress. The first one starts with the increase in the content of caffeoyl-quinic acids, substances with strong antioxidant activity, until the 16th day of water suppression. When RWC reached less than 80% and 70%, in winter and summer respectively, it was observed an increase in polyols and monosaccharides, followed by an increment in the content of RFO, suggesting osmotic adjustment. Amino acids, such as GABA and asparagine, also increased due to 16 days of water suppression. During rehydration, the levels of the mentioned compounds became similar to those found at the beginning of the experiment and when compared to daily watered plants. We conclude that the tolerance of B. purpurea to dehydration involves the perception of water deficit intensity, which seems to result in different strategies to overcome the gradient of water availability imposed along a certain period of stress mainly during winter. Data from summer experiment indicate that the metabolism of B. pupurea was already primed for drought stress. The accumulation of phenolics in summer seemed to be more temperature and irradiance-dependent than on the RWC.

  6. Perceptual advertisement by the prey of stalking or ambushing predators.

    Science.gov (United States)

    Broom, Mark; Ruxton, Graeme D

    2012-12-21

    There has been previous theoretical explorations of the stability of signals by prey that they have detected a stalking or ambush predator, where such perceptual advertisement dissuades the predator from attacking. Here we use a game theoretical model to extend the theory to consider some empirically-motivated complexities: (i) many perceptual advertisement signals appear to have the potential to vary in intensity, (ii) higher intensity signals are likely to be most costly to produce, and (iii) some high-cost signals (such as staring directly at the predator) can only be utilised if the prey is very confident of the existence of a nearby predator (that is, there are reserved or unfakable signals). We demonstrate that these complexities still allow for stable signalling. However, we do not find solutions where prey use a range of signal intensities to signal different degrees of confidence in the proximity of a predator; with prey simply adopting a binary response of not signalling or always signalling at the same fixed level. However this fixed level will not always be the cheapest possible signal, and we predict that prey that require more certainty about proximity of a predator will use higher-cost signals. The availability of reserved signals does not prohibit the stability of signalling based on lower-cost signals, but we also find circumstances where only the reserved signal is used. We discuss the potential to empirically test our model predictions, and to develop theory further to allow perceptual advertisement to be combined with other signalling functions.

  7. It takes guts to locate elusive crustacean prey

    Science.gov (United States)

    Lasley-Rasher, R. S.; Brady, D. C.; Smith, B. E.; Jumars, P. A.

    2016-02-01

    Mobile crustacean prey, i.e., crangonid, euphausiid, mysid, and pandalid shrimp, are vital links in marine food webs. Their intermediate sizes and characteristic caridoid escape responses lead to chronic underestimation when sampling at large spatial scales with either plankton nets or large trawl nets. Here, as discrete sampling units, we utilize individual fish diets (i.e., fish biosamplers) collected by the U.S. National Marine Fisheries Service and Northeast Fisheries Science Center to examine abundance and location of these prey families over large spatial and temporal scales in the northeastern U.S. shelf large ecosystem. Fish biosamplers revealed significant spatial shifts in prey in early spring. Distributions of mysids and crangonids in fish diets shoaled significantly from February to March. Distributions of euphausiids and pandalids in fish diets shifted northward during March. Of multiple hypotheses for these shifts, prey migration is most strongly supported. Future efforts can apply this method to address questions regarding temporal patterns or shifts in prey distribution and abundance that may be driven by large-scale stressors such as food-web shifts or climate change

  8. Prey-dependent retention of dimethylsulfoniopropionate (DMSP) by mixotrophic dinoflagellates.

    Science.gov (United States)

    Lee, Hyunwoo; Park, Ki-Tae; Lee, Kitack; Jeong, Hae Jin; Yoo, Yeong Du

    2012-03-01

    We investigated the retention of dimethylsulfoniopropionate (DMSP) in phototrophic dinoflagellates arising from mixotrophy by estimating the cellular content of DMSP in Karlodinium veneficum (mixotrophic growth) fed for 7-10 days on either DMSP-rich Amphidinium carterae (phototrophic growth only) or DMSP-poor Teleaulax sp. (phototrophic growth only). In K. veneficum fed on DMSP-poor prey, the cellular content of DMSP remained almost unchanged regardless of the rate of feeding, whereas the cellular content of DMSP in cells of K. veneficum fed on DMSP-rich prey increased by as much as 21 times the cellular concentration derived exclusively from phototrophic growth. In both cases, significant fractions (10-32% in the former case and 55-65% in the latter) of the total DMSP ingested by K. veneficum were transformed into dimethylsulfide and other biochemical compounds. The results may indicate that the DMSP content of prey species affects temporal variations in the cellular DMSP content of mixotrophic dinoflagellates, and that mixotrophic dinoflagellates produce DMS through grazing on DMSP-rich preys. Additional studies should be performed to examine the universality of our finding in other mixotrophic dinoflagellates feeding on diverse prey species.

  9. A Comparison Study of the Effects of Echinacea purpurea Ethanolic Extract and Mesna on Cyclophosphamide-Induced Macroscopic Fetal Defects in Rats

    Directory of Open Access Journals (Sweden)

    Hossein Najafzadeh Varzi

    2009-03-01

    Full Text Available Objective(s There are some reports that the teratogenic effects of cyclophosphamide (CPA can be prevented by application of antioxidant drugs and stimulation of the maternal immune system. Echinacea purpurea extract is antioxidative and immunomodulator drug. Mesna (Sodium 2-mercaptoethane sulfonate is used for decreasing side effects of CPA, especially hemorrhagic cystitis. In this study, we compared the prophylactic effects of mesna and Echinacea extract on teratogenic effects of CPA. Materials and Methods This study was performed on 32 pregnant rats that were divided into 4 groups. The first group (control group received normal saline and the other groups received CPA (15 mg/kg intraperitoneally on 13th day of gestation. Mesna and E. purpurea extracts were administrated at doses of 100 and 400 mg/kg by IP injection, respectively, along with it and 12 hr later, after CPA injection. Rats were dissected on day 20 of gestation, embryos harvested and after determination of gross malformations they were stained by Alizarin red-Alcian blue method. ResultsCleft palate incidence was 38.46, 30.77 and 14.28% in fetuses of rats that received only CPA, CPA with mesna and CPA with Echinacea extract, respectively. In addition, skeletal anomalies incidence including limbs, vertebra, sternum, and scapula defects were decreased by Echinacea extract.ConclusionE. purpurea has significant effect on preventing CPA-induced malformations and better prophylactic effect than mesna on cases like CPA-induced cleft palate.

  10. Domestication and the distribution of genetic variation in wild and cultivated populations of the Mesoamerican fruit tree Spondias purpurea L. (Anacardiaceae).

    Science.gov (United States)

    Miller, Allison J; Schaal, Barbara A

    2006-05-01

    Domestication occurs as humans select and cultivate wild plants in agricultural habitats. The amount and structure of variation in contemporary cultivated populations has been shaped, in part, by how genetic material was transferred from one cultivated generation to the next. In some cultivated tree species, domestication involved a shift from sexually reproducing wild populations to vegetatively propagated cultivated populations; however, little is known about how domestication has impacted variation in these species. We employed AFLP data to explore the amount, structure, and distribution of variation in clonally propagated domesticated populations and sexually reproducing wild populations of the Neotropical fruit tree, Spondias purpurea (Anacardiaceae). Cultivated populations from three different agricultural habitats were included: living fences, backyards, and orchards. AFLP data were analysed using measures of genetic diversity (% polymorphic loci, Shannon's diversity index, Nei's gene diversity, panmictic heterozygosity), population structure (F(ST) analogues), and principal components analyses. Levels of genetic variation in cultivated S. purpurea populations are significantly less than variation found in wild populations, although the amount of diversity varies in different agricultural habitats. Cultivated populations have a greater proportion of their genetic variability distributed among populations than wild populations. The genetic structure of backyard populations resembles that of wild populations, but living fence and orchard populations have 1/3 more variability distributed among populations, most likely a reflection of relative levels of vegetative reproduction. Finally, these results suggest that S. purpurea was domesticated in two distinct regions within Mesoamerica.

  11. Safety and Efficacy Profile of Echinacea purpurea to Prevent Common Cold Episodes: A Randomized, Double-Blind, Placebo-Controlled Trial

    Directory of Open Access Journals (Sweden)

    M. Jawad

    2012-01-01

    Full Text Available Objective. To investigate the safety (risk and efficacy (benefit of Echinacea purpurea extract in the prevention of common cold episodes in a large population over a 4-month period. Methods. 755 healthy subjects were allocated to receive either an alcohol extract from freshly harvested E. purpurea (95% herba and 5% root or placebo. Participants were required to record adverse events and to rate cold-related issues in a diary throughout the investigation period. Nasal secretions were sampled at acute colds and screened for viruses. Results. A total of 293 adverse events occurred with Echinacea and 306 with placebo treatment. Nine and 10% of participants experienced adverse events, which were at least possibly related to the study drug (adverse drug reactions. Thus, the safety of Echinacea was noninferior to placebo. Echinacea reduced the total number of cold episodes, cumulated episode days within the group, and pain-killer medicated episodes. Echinacea inhibited virally confirmed colds and especially prevented enveloped virus infections (P<0.05. Echinacea showed maximal effects on recurrent infections, and preventive effects increased with therapy compliance and adherence to the protocol. Conclusions. Compliant prophylactic intake of E. purpurea over a 4-month period appeared to provide a positive risk to benefit ratio.

  12. Safety and Efficacy Profile of Echinacea purpurea to Prevent Common Cold Episodes: A Randomized, Double-Blind, Placebo-Controlled Trial.

    Science.gov (United States)

    Jawad, M; Schoop, R; Suter, A; Klein, P; Eccles, R

    2012-01-01

    Objective. To investigate the safety (risk) and efficacy (benefit) of Echinacea purpurea extract in the prevention of common cold episodes in a large population over a 4-month period. Methods. 755 healthy subjects were allocated to receive either an alcohol extract from freshly harvested E. purpurea (95% herba and 5% root) or placebo. Participants were required to record adverse events and to rate cold-related issues in a diary throughout the investigation period. Nasal secretions were sampled at acute colds and screened for viruses. Results. A total of 293 adverse events occurred with Echinacea and 306 with placebo treatment. Nine and 10% of participants experienced adverse events, which were at least possibly related to the study drug (adverse drug reactions). Thus, the safety of Echinacea was noninferior to placebo. Echinacea reduced the total number of cold episodes, cumulated episode days within the group, and pain-killer medicated episodes. Echinacea inhibited virally confirmed colds and especially prevented enveloped virus infections (P Echinacea showed maximal effects on recurrent infections, and preventive effects increased with therapy compliance and adherence to the protocol. Conclusions. Compliant prophylactic intake of E. purpurea over a 4-month period appeared to provide a positive risk to benefit ratio.

  13. Isomeric C12-alkamides from the roots of Echinacea purpurea improve basal and insulin-dependent glucose uptake in 3T3-L1 adipocytes.

    Science.gov (United States)

    Kotowska, Dorota; El-Houri, Rime B; Borkowski, Kamil; Petersen, Rasmus K; Fretté, Xavier C; Wolber, Gerhard; Grevsen, Kai; Christensen, Kathrine B; Christensen, Lars P; Kristiansen, Karsten

    2014-12-01

    Echinacea purpurea has been used in traditional medicine as a remedy for the treatment and prevention of upper respiratory tract infections and the common cold. Recent investigations have indicated that E. purpurea also has an effect on insulin resistance. A dichloromethane extract of E. purpurea roots was found to enhance glucose uptake in adipocytes and to activate peroxisome proliferator-activated receptor γ. The purpose of the present study was to identify the bioactive compounds responsible for the potential antidiabetic effect of the dichloromethane extract using a bioassay-guided fractionation approach. Basal and insulin-dependent glucose uptake in 3T3-L1 adipocytes were used to assess the bioactivity of extract, fractions and isolated metabolites. A peroxisome proliferator-activated receptor γ transactivation assay was used to determine the peroxisome proliferator-activated receptor γ activating properties of the extract, active fractions and isolated metabolites. Two novel isomeric dodeca-2E,4E,8Z,10E/Z-tetraenoic acid 2-methylbutylamides together with two known C12-alkamides and α-linolenic acid were isolated from the active fractions. The isomeric C12-alkamides were found to activate peroxisome proliferator-activated receptor γ, to increase basal and insulin-dependent glucose uptake in adipocytes in a dose-dependent manner, and to exhibit characteristics of a peroxisome proliferator-activated receptor γ partial agonist. Georg Thieme Verlag KG Stuttgart · New York.

  14. Preliminary data on antibacterial activity of Echinacea purpurea-associated bacterial communities against Burkholderia cepacia complex strains, opportunistic pathogens of Cystic Fibrosis patients.

    Science.gov (United States)

    Chiellini, Carolina; Maida, Isabel; Maggini, Valentina; Bosi, Emanuele; Mocali, Stefano; Emiliani, Giovanni; Perrin, Elena; Firenzuoli, Fabio; Mengoni, Alessio; Fani, Renato

    2017-03-01

    Burkholderia cepacia complex bacteria (Bcc) represent a serious threat for immune-compromised patient affected by Cystic Fibrosis (CF) since they are resistant to many substances and to most antibiotics. For this reason, the research of new natural compounds able to inhibit the growth of Bcc strains has raised new interest during the last years. A source of such natural compounds is represented by medicinal plants and, in particular, by bacterial communities associated with these plants able to produce molecules with antimicrobial activity. In this work, a panel of 151 (endophytic) bacteria isolated from three different compartments (rhizospheric soil, roots, and stem/leaves) of the medicinal plant Echinacea purpurea were tested (using the cross-streak method) for their ability to inhibit the growth of 10 Bcc strains. Data obtained revealed that bacteria isolated from the roots of E. purpurea are the most active in the inhibition of Bcc strains, followed by bacteria isolated from the rhizospheric soil, and endophytes from stem/leaf compartment. At the same time, Bcc strains of environmental origin showed a higher resistance toward inhibition than the Bcc strains with clinical (i.e. CF patients) origin. Differences in the inhibition activity of E. purpurea-associated bacteria are mainly linked to the environment -the plant compartment- rather than to their taxonomical position. Copyright © 2016 Elsevier GmbH. All rights reserved.

  15. Capture success and efficiency of dragonflies pursuing different types of prey.

    Science.gov (United States)

    Combes, S A; Salcedo, M K; Pandit, M M; Iwasaki, J M

    2013-11-01

    The dynamics of predator-prey interactions vary enormously, due both to the heterogeneity of natural environments and to wide variability in the sensorimotor systems of predator and prey. In addition, most predators pursue a range of different types of prey, and most organisms are preyed upon by a variety of predators. We do not yet know whether predators employ a general kinematic and behavioral strategy, or whether they tailor their pursuits to each type of prey; nor do we know how widely prey differ in their survival strategies and sensorimotor capabilities. To gain insight into these questions, we compared aerial predation in 4 species of libelluid dragonflies pursuing 4 types of dipteran prey, spanning a range of sizes. We quantified the proportion of predation attempts that were successful (capture success), as well as the total time spent and the distance flown in pursuit of prey (capture efficiency). Our results show that dragonfly prey-capture success and efficiency both decrease with increasing size of prey, and that average prey velocity generally increases with size. However, it is not clear that the greater distances and times required for capturing larger prey are due solely to the flight performance (e.g., speed or evasiveness) of the prey, as predicted. Dragonflies initiated pursuits of large prey when they were located farther away, on average, as compared to small prey, and the total distance flown in pursuit was correlated with initial distance to the prey. The greater initial distances observed during pursuits of larger prey may arise from constraints on dragonflies' visual perception; dragonflies typically pursued prey subtending a visual angle of 1°, and rarely pursued prey at visual angles greater than 3°. Thus, dragonflies may be unable to perceive large prey flying very close to their perch (subtending a visual angle greater than 3-4°) as a distinct target. In comparing the performance of different dragonfly species that co-occur in the

  16. Biomechanics (Communication arising): prey attack by a large theropod dinosaur.

    Science.gov (United States)

    Frazzetta, T H; Kardong, Kenneth V

    2002-03-28

    Prey-capture strategies in carnivorous dinosaurs have been inferred from the biomechanical features of their tooth structure, the estimated bite force produced, and their diet. Rayfield et al. have used finite-element analysis (FEA) to investigate such structure-function relationships in Allosaurus fragilis, and have found that the skull was designed to bear more stress than could be generated by simple biting. They conclude that this large theropod dinosaur delivered a chop-and-slash 'hatchet' blow to its prey, which it approached with its mouth wide open before driving its upper tooth row downwards. We argue that this mode of predation is unlikely, and that the FEA results, which relate to an 'overengineered' skull, are better explained by the biomechanical demands of prey capture. Understanding the mechanics of predation is important to our knowledge of the feeding habits of carnivorous dinosaurs and for accurate reconstruction their lifestyles.

  17. Influence of poisoned prey on foraging behavior of ferruginous hawks

    Science.gov (United States)

    Vyas, Nimish B.; Kuncir, Frank; Clinton, Criss C.

    2017-01-01

    We recorded 19 visits by ferruginous hawks (Buteo regalis) over 6 d at two black–tailed prairie dog (Cynomys ludovicianus) subcolonies poisoned with the rodenticide Rozol® Prairie Dog Bait (0.005% chlorophacinone active ingredient) and at an adjacent untreated subcolony. Before Rozol® application ferruginous hawks foraged in the untreated and treated subcolonies but after Rozol® application predation by ferruginous hawks was only observed in the treated subcolonies. We suggest that ferruginous hawks' preference for hunting in the treated subcolonies after Rozol® application was influenced by the availability of easy-to-capture prey, presumably due to Rozol® poisoning. The energetically beneficial behavior of favoring substandard prey may increase raptor encounters with rodenticide exposed animals if prey vulnerability has resulted from poisoning.

  18. Predator-prey oscillations can shift when diseases become endemic.

    Science.gov (United States)

    Bate, Andrew M; Hilker, Frank M

    2013-01-07

    In epidemiology, knowing when a disease is endemic is important. This is usually done by finding the basic reproductive number, R(0), using equilibrium-based calculations. However, oscillatory dynamics are common in nature. Here, we model a disease with density dependent transmission in an oscillating predator-prey system. The condition for disease persistence in predator-prey cycles is based on the time-average density of the host and not the equilibrium density. Consequently, the time-averaged basic reproductive number R(0)¯ is what determines whether a disease is endemic, and not on the equilibrium-based basic reproductive number R(0)(*). These findings undermine any R(0) analysis based solely on steady states when predator-prey oscillations exist for density dependent diseases.

  19. Predator-prey interactions, flight initiation distance and brain size.

    Science.gov (United States)

    Møller, A P; Erritzøe, J

    2014-01-01

    Prey avoid being eaten by assessing the risk posed by approaching predators and responding accordingly. Such an assessment may result in prey-predator communication and signalling, which entail further monitoring of the predator by prey. An early antipredator response may provide potential prey with a selective advantage, although this benefit comes at the cost of disturbance in terms of lost foraging opportunities and increased energy expenditure. Therefore, it may pay prey to assess approaching predators and determine the likelihood of attack before fleeing. Given that many approaching potential predators are detected visually, we hypothesized that species with relatively large eyes would be able to detect an approaching predator from afar. Furthermore, we hypothesized that monitoring of predators by potential prey relies on evaluation through information processing by the brain. Therefore, species with relatively larger brains for their body size should be better able to monitor the intentions of a predator, delay flight for longer and hence have shorter flight initiation distances than species with smaller brains. Indeed, flight initiation distances increased with relative eye size and decreased with relative brain size in a comparative study of 107 species of birds. In addition, flight initiation distance increased independently with size of the cerebellum, which plays a key role in motor control. These results are consistent with cognitive monitoring as an antipredator behaviour that does not result in the fastest possible, but rather the least expensive escape flights. Therefore, antipredator behaviour may have coevolved with the size of sense organs, brains and compartments of the brain involved in responses to risk of predation.

  20. Ocean acidification affects prey detection by a predatory reef fish.

    Directory of Open Access Journals (Sweden)

    Ingrid L Cripps

    Full Text Available Changes in olfactory-mediated behaviour caused by elevated CO(2 levels in the ocean could affect recruitment to reef fish populations because larval fish become more vulnerable to predation. However, it is currently unclear how elevated CO(2 will impact the other key part of the predator-prey interaction--the predators. We investigated the effects of elevated CO(2 and reduced pH on olfactory preferences, activity levels and feeding behaviour of a common coral reef meso-predator, the brown dottyback (Pseudochromis fuscus. Predators were exposed to either current-day CO(2 levels or one of two elevated CO(2 levels (∼600 µatm or ∼950 µatm that may occur by 2100 according to climate change predictions. Exposure to elevated CO(2 and reduced pH caused a shift from preference to avoidance of the smell of injured prey, with CO(2 treated predators spending approximately 20% less time in a water stream containing prey odour compared with controls. Furthermore, activity levels of fish was higher in the high CO(2 treatment and feeding activity was lower for fish in the mid CO(2 treatment; indicating that future conditions may potentially reduce the ability of the fish to respond rapidly to fluctuations in food availability. Elevated activity levels of predators in the high CO(2 treatment, however, may compensate for reduced olfactory ability, as greater movement facilitated visual detection of food. Our findings show that, at least for the species tested to date, both parties in the predator-prey relationship may be affected by ocean acidification. Although impairment of olfactory-mediated behaviour of predators might reduce the risk of predation for larval fishes, the magnitude of the observed effects of elevated CO(2 acidification appear to be more dramatic for prey compared to predators. Thus, it is unlikely that the altered behaviour of predators is sufficient to fully compensate for the effects of ocean acidification on prey mortality.

  1. The stabilizing effects of genetic diversity on predator-prey dynamics.

    Science.gov (United States)

    Steiner, Christopher F; Masse, Jordan

    2013-01-01

    Heterogeneity among prey in their susceptibility to predation is a potentially important stabilizer of predator-prey interactions, reducing the magnitude of population oscillations and enhancing total prey population abundance. When microevolutionary responses of prey populations occur at time scales comparable to population dynamics, adaptive responses in prey defense can, in theory, stabilize predator-prey dynamics and reduce top-down effects on prey abundance. While experiments have tested these predictions, less explored are the consequences of the evolution of prey phenotypes that can persist in both vulnerable and invulnerable classes. We tested this experimentally using a laboratory aquatic system composed of the rotifer Brachionus calyciflorus as a predator and the prey Synura petersenii, a colony-forming alga that exhibits genetic variation in its propensity to form colonies and colony size (larger colonies are a defense against predators). Prey populations of either low initial genetic diversity and low adaptive capacity or high initial genetic diversity and high adaptive capacity were crossed with predator presence and absence. Dynamics measured over the last 127 days of the 167-day experiment revealed no effects of initial prey genetic diversity on the average abundance or temporal variability of predator populations. However, genetic diversity and predator presence/absence interactively affected prey population abundance and stability; diversity of prey had no effects in the absence of predators but stabilized dynamics and increased total prey abundance in the presence of predators. The size structure of the genetically diverse prey populations diverged from single strain populations in the presence of predators, showing increases in colony size and in the relative abundance of cells found in colonies. Our work sheds light on the adaptive value of colony formation and supports the general view that genetic diversity and intraspecific trait variation of

  2. Sympatric Masticophis flagellum and Coluber constrictor select vertebrate prey at different levels of taxonomy

    Science.gov (United States)

    Halstead, B.J.; Mushinsky, H.R.; McCoy, E.D.

    2008-01-01

    Masticophis flagellum (Coachwhip) and Coluber constrictor (Eastern Racer) are widespread North American snakes with similar foraging modes and habits. Little is known about the selection of prey by either species, and despite their apparently similar foraging habits, comparative studies of the foraging ecology of sympatric M. flagellum and C. constrictor are lacking. We examined the foraging ecology and prey selection of these actively foraging snakes in xeric, open-canopied Florida scrub habitat by defining prey availability separately for each snake to elucidate mechanisms underlying geographic, temporal, and interspecific variation in predator diets. Nineteen percent of M. flagellum and 28% of C. constrictor contained stomach contents, and most snakes contained only one prey item. Mean relative prey mass for both species was less than 10%. Larger C. constrictor consumed larger prey than small individuals, but this relationship disappeared when prey size was scaled to snake size. Masticophis flagellum was selective at the prey category level, and positively selected lizards and mammals; however, within these categories it consumed prey species in proportion to their availability. In contrast, C. constrictor preyed upon prey categories opportunistically, but was selective with regard to species. Specifically, C. constrictor positively selected Hyla femoralis (Pine Woods Treefrog) and negatively selected Bufo querclcus (Oak Toad), B. terrestris (Southern Toad), and Gastrophryne carolinensis (Eastern Narrowmouth Toad). Thus, despite their similar foraging habits, M. flagellum and C. constrictor select different prey and are selective of prey at different levels of taxonomy. ?? 2008 by the American Society of Ichthyologists and Herpetologists.

  3. On a predator-prey system of Gause type.

    Science.gov (United States)

    Hasík, Karel

    2010-01-01

    In this paper a Gause type model of interactions between predator and prey population is considered. We deal with the sufficient condition due to Kuang and Freedman in the generalized form including a kind of weight function. In a previous paper we proved that the existence of such weight function implies the uniqueness of limit cycle. In the present paper we give a new condition equivalent to the existence of a weight function (Theorem 4.4). As a consequence of our result, it is shown that some simple qualitative properties of the trophic function and the prey isocline ensure the uniqueness of limit cycle.

  4. On predator-prey systems and small-gain theorems.

    Science.gov (United States)

    Leenheer, Patrick De; Angeli, David; Sontag, Eduardo D

    2005-01-01

    This paper deals with an almost global convergence result for Lotka-Volterra systems with predator-prey interactions. These systems can be written as (negative) feedback systems. The subsystems of the feedback loop are monotone control systems, possessing particular input-output properties. We use a small-gain theorem, adapted to a context of systems with multiple equilibrium points to obtain the desired almost global convergence result, which provides sufficient conditions to rule out oscillatory or more complicated behavior that is often observed in predator-prey systems.

  5. Global analysis of Ivlev's type predator-prey dynamic systems

    Institute of Scientific and Technical Information of China (English)

    XIAO Hai-bin

    2007-01-01

    Consider a class of Ivlev's type predator-prey dynamic systems with prey and predator both having linear density restricts. By using the qualitative methods of ODE,the global stability of positive equilibrium and existence and uniqueness of non-small amplitude stable limit cycle are obtained. Especially under certain conditions, it shows that existence and uniqueness of non-small amplitude stable limit cycle is equivalent to the local un-stability of positive equilibrium and the local stability of positive equilibrium implies its global stability. That is to say, the global dynamic of the system is entirely determined by the local stability of the positive equilibrium.

  6. Stochastic Lattice Gas Model for a Predator-Prey System

    CERN Document Server

    Satulovsky, J E; Satulovsky, Javier; Tome, Tania

    1994-01-01

    We propose a stochastic lattice gas model to describe the dynamics of two animal species population, one being a predator and the other a prey. This model comprehends the mechanisms of the Lotka-Volterra model. Our analysis was performed by using a dynamical mean-field approximation and computer simulations. Our results show that the system exhibits an oscillatory behavior of the population densities of prey and predators. For the sets of parameters used in our computer simulations, these oscillations occur at a local level. Mean-field results predict synchronized collective oscillations.

  7. Bogdanov-Takens bifurcation in a predator-prey model

    Science.gov (United States)

    Liu, Zhihua; Magal, Pierre; Xiao, Dongmei

    2016-12-01

    In this paper, we investigate a class of predator-prey model with age structure and discuss whether the model can undergo Bogdanov-Takens bifurcation. The analysis is based on the normal form theory and the center manifold theory for semilinear equations with non-dense domain combined with integrated semigroup theory. Qualitative analysis indicates that there exist some parameter values such that this predator-prey model has an unique positive equilibrium which is Bogdanov-Takens singularity. Moreover, it is shown that under suitable small perturbation, the system undergoes the Bogdanov-Takens bifurcation in a small neighborhood of this positive equilibrium.

  8. Echinacea Purpurea Significantly Induces Cytochrome P450 3A (CYP3A) but does not alter Lopinavir-Ritonavir Exposure in Healthy Subjects

    Science.gov (United States)

    Penzak, Scott R.; Robertson, Sarah M.; Hunt, Jennifer D.; Chairez, Cheryl; Malati, Christine Y.; Alfaro, Raul M.; Stevenson, James M.; Candidate, Pharm.D.; Kovacs, Joseph A.

    2012-01-01

    Study Objective To determine the influence of Echinacea purpurea on the pharmacokinetics of lopinavir-ritonavir, and on CYP3A and P-glycoprotein (P-gp) activity using the probe substrates midazolam, and fexofenadine, respectively. Design Open label, single-sequence pharmacokinetic study. Setting Outpatient clinic in a Federal Government research hospital. Subjects Thirteen (8 males) healthy volunteers (median age: 31 yrs). Measurements and main results Healthy volunteers received lopinavir-ritonavir (400/100 mg) twice daily for 30 days. On study day 16, subjects began taking Echinacea purpurea 500 mg three times daily, which they continued for four weeks, the first two weeks in combination with lopinavir-ritonavir. On days 15 and 30 of lopinavir-ritonavir administration (pre and post-Echinacea, respectively), serial blood samples were collected over 12 hrs to determine lopinavir and ritonavir concentrations and subsequent pharmacokinetic parameters using non-compartmental methods. Study subjects also received single doses of midazolam (8 mg orally) and fexofenadine (120 mg orally) before- and after 28 days of Echinacea purpurea to assess CYP3A and P-glycoprotein (P-gp) activity, respectively. Neither lopinavir nor ritonavir pharmacokinetics were significantly altered by 2 weeks of Echinacea coadministration. The geometric mean ratios (GMR, 90% CI) for lopinavir area under the concentration vs. time curve from zero to 12 hrs (AUC0–12) and maximum concentration (post-Echinacea/pre-Echinacea) were 0.96 (0.83, 1.10) and 1.00 (0.88, 1.12), respectively (P > 0.05). Conversely, GMRs (90% CIs) for midazolam AUC from time zero to infinity (AUC0-∞) and oral clearance were 0.73 (0.61, 0.85) (P = 0.008) and 1.37 (1.10, 1.63) (P = 0.02), respectively. Fexofenadine pharmacokinetics did not significantly differ pre- and post-echinacea administration (P > 0.05). Conclusion Echinacea purpurea induced CYP3A activity but did not alter lopinavir concentrations, most likely due to

  9. Non-specific symbiotic germination of Cynorkis purpurea (Thouars) Kraezl., a habitat-specific terrestrial orchid from the Central Highlands of Madagascar.

    Science.gov (United States)

    Rafter, M; Yokoya, K; Schofield, E J; Zettler, L W; Sarasan, V

    2016-08-01

    Orchids, particularly terrestrial taxa, rely mostly on basidiomycete fungi in the Cantharellales and Sebacinales that trigger the process of seed germination and/or initiate the full development of the seedling. During the course of development, orchids may associate with the same fungus, or they may enlist other types of fungi for their developmental needs leading to resilience in a natural setting. This study examined in vitro seed germination and seedling developmental behavior of Cynorkis purpurea, a terrestrial orchid from the Central Highlands of Madagascar. This species is mostly restricted to gallery forests in the Itremo Massif, in moist substrate between rocks bordering streams. The main objective was to understand the influence of diverse mycorrhizal fungi on seed germination and further development of C. purpurea. The study aims to compare symbiotic versus asymbiotic germination and seedling development with seeds and fungi collected from a 13-km(2) area in the Itremo region. Seeds collected from the wild were sown with diverse orchid mycorrhizal fungi (OMF) spanning 12 operational taxonomic units (OTUs) in three genera (Tulasnella, Ceratobasidium, and Sebacina) acquired from different habitats. Treatments were assessed in terms of the percentage of germinated seeds and fully developed seedlings against those in asymbiotic control media treatments. Overall, OMF significantly improved seedling development within the 12-week experiment period. Sebacina as a genus was the most effective at promoting seedling development of C. purpurea, as well as having the ability to enter into successful symbiotic relationships with orchids of different life forms; this new knowledge may be especially useful for orchid conservation practiced in tropical areas like Madagascar. A Sebacina isolate from an epiphytic seedling of Polystachya concreta was the most effective at inducing rapid seedling development and was among the five that outperformed fungi isolated from roots

  10. Changes in soft-bottom prey communities along a gradient in sea otter predation around Kodiak Island, Alaska

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Sea otters, Enhydra lutris, have a dramatic impact on bivalve prey populations and non-prey infaunal communities around Kodiak Island. The major prey species was the...

  11. Density-dependent prey mortality is determined by the spatial scale of predator foraging.

    Science.gov (United States)

    McCarthy, Erin K; White, J Wilson

    2016-02-01

    Foraging theory predicts which prey patches predators should target. However, in most habitats, what constitutes a 'patch' and how prey density is calculated are subjective concepts and depend on the spatial scale at which the predator (or scientist) is observing. Moreover, the predator's 'foraging scale' affects prey population dynamics: predators should produce directly density-dependent (DDD) prey mortality at the foraging scale, but inversely density-dependent (IDD) mortality (safety-in-numbers) at smaller scales. We performed the first experimental test of these predictions using behavioral assays with guppies (Poecilia reticulata) feeding on bloodworm 'prey' patches. The guppy's foraging scale had already been estimated in a prior study. Our experimental results confirmed theoretical predictions: predation was IDD when prey were aggregated at a scale smaller than the foraging scale, but not when prey were aggregated at larger scales. These results could be used to predict outcomes of predator-prey interactions in continuous, non-discrete habitats in the field.

  12. Is the red spotted green frog Hypsiboas punctatus (Anura: Hylidae) selecting its preys? The importance of prey availability.

    Science.gov (United States)

    López, Javier A; Scarabotti, Pablo A; Medrano, María C; Ghirardi, Romina

    2009-09-01

    The study of the feeding ecology of amphibians is an old issue in herpetology. Notwithstanding, the lack of food resources data in many studies of amphibians feeding has lead to partial understanding of frog feeding strategies. In this study we evaluate the trophic selectivity of a red spotted green frog (Hypsiboas punctatus) population from a Middle Paraná River floodplain pond in Argentina, and discuss the importance of prey availability data when interpreting results from diet analysis. We analyzed the gut contents of 47 H. punctatus adults and compared frog's diet with the environmental food resources. Prey availability was estimated by systematically seep-netting the microhabitat where anurans were localized foraging. We identified 33 taxonomic categories from gastrointestinal contents. Numerically, the most important prey categories were dipterans, followed by hemipterans, homopterans and coleopterans. The diet similarity between males and females was high and no statistical differences in diet composition were found. The most abundant food resources in the environment were dipterans, coleopterans, homopterans and collembolans. In order to assess whether frogs were selecting their preys, we calculated Pianka's niche overlap index and Jacobs' electivity index comparing gut contents to prey availability data. Trophic niche overlap was medium but significantly higher than expected by chance. The electivity index indicated that H. punctatus foraged dipterans slightly above their environmental abundance. Among the secondary preys, hemipterans were foraged selectively, homopterans were consumed in the same proportion to their occurrence in the environment, coleopterans were foraged quite under their availability and collembolans were practically ignored by frogs. Without food resources data, H. punctatus could be classified as a specialist feeder, but dipterans also were quite abundant in the environment. Our results show that H. punctatus fit better as a

  13. Coexistence of steady state for a diffusive prey-predator model with harvesting

    Directory of Open Access Journals (Sweden)

    Yan Li

    2016-07-01

    Full Text Available In this article, we study a diffusive prey-predator model with modified Leslie-Gower term and Michaelis-Menten type prey harvesting, subject to homogeneous Dirichlet boundary conditions. Treating the prey harvesting parameter as a bifurcation parameter, we obtain the existence, bifurcation and stability of coexistence steady state solutions. We use the method of upper and lower solutions, degree theory in cones, and bifurcation theory. The conclusions show the importance of prey harvesting in the model.

  14. Antagonistic evolution in an aposematic predator-prey signaling system.

    Science.gov (United States)

    Speed, Michael P; Franks, Daniel W

    2014-10-01

    Warning signals within species, such as the bright colors of chemically defended animals, are usually considered mutualistic, monomorphic traits. Such a view is however increasingly at odds with the growing empirical literature, showing nontrivial levels of signal variation within prey populations. Key to understanding this variation, we argue, could be a recognition that toxicity levels frequently vary within populations because of environmental heterogeneity. Inequalities in defense may undermine mutualistic monomorphic signaling, causing evolutionary antagonism between loci that determine appearance of less well-defended and better defended prey forms within species. In this article, we apply a stochastic model of evolved phenotypic plasticity to the evolution of prey signals. We show that when toxicity levels vary, then antagonistic interactions can lead to evolutionary conflict between alleles at different signaling loci, causing signal evolution, "red queen-like" evolutionary chase, and one or more forms of signaling equilibria. A key prediction is that variation in the way that predators use information about toxicity levels in their attack behaviors profoundly affects the evolutionary characteristics of the prey signaling systems. Environmental variation is known to cause variation in many qualities that organisms signal; our approach may therefore have application to other signaling systems.

  15. PERMANENCE OF A NONLINEAR DISCRETE PREDATOR-PREY SYSTEM

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    In this paper,we study a nonlinear discrete predator-prey model. We obtain a set of suffcient conditions which guarantee the permanence of the system. And an example together with its numeric simulation is presented to show the feasibility of our result.

  16. Tiger beetle's pursuit of prey depends on distance

    Science.gov (United States)

    Noest, Robert; Wang, Jane

    2015-03-01

    Tiger beetles are fast predators capable of chasing prey under closed-loop visual guidance. We investigated their control system using high-speed digital recordings of beetles chasing a moving prey dummy in a laboratory arena. Analysis reveals that the beetle uses a proportional control law in which the angular position of the prey relative to the beetle's body axis drives the beetle's angular velocity with a delay of about 28 ms. The system gain is shown to depend on the beetle-prey distance in a pattern indicating three hunting phases over the observed distance domain. We show that to explain this behavior the tiger beetle must be capable of visually determining the distance to its target and using that to adapt the gain in its proportional control law. We will end with a discussion on the possible methods for distance detection by the tiger beetle and focus on two of them. Motion parallax, using the natural head sway induced by the walking gait of the tiger beetle, is shown to have insufficient distance range. However elevation in the field of vision, using the angle with respect to the horizon at which a target is observed, has a much larger distance range and is a prime candidate for the mechanism of visual distance detection in the tiger beetle.

  17. An investigation into the chemical composition of alternative invertebrate prey

    NARCIS (Netherlands)

    Oonincx, D.G.A.B.; Dierenfeld, E.S.

    2012-01-01

    The aim of this study was to determine the chemical composition of eight invertebrate species and evaluate their suitability as alternative prey. The species selected were rusty red cockroaches (Blatta lateralis), six-spotted cockroaches (Eublaberus distanti), Madagascar hissing cockroaches (Grompha

  18. Hydrodynamics of prey capture in sharks : effects of substrate

    NARCIS (Netherlands)

    Nauwelaerts, Sandra; Wilga, Cheryl; Sanford, Christopher; Lauder, George

    2007-01-01

    In suction feeding, a volume of water is drawn into the mouth of a predator. Previous studies of suction feeding in fishes have shown that significant fluid velocities are confined to a region within one mouth width from the mouth. Therefore, the predator must be relatively close to the prey to ensu

  19. Modelling prey consumption and switching by UK grey seals

    DEFF Research Database (Denmark)

    Smout, Sophie; Rindorf, Anna; Hammond, Philip S.

    2014-01-01

    Grey seals (Halichoerus grypus) are adaptable generalist predatorswhose diet includes commercial fish species such as cod. Consumption by the seals may reduce the size of some fish stocks or have an adverse effect on stock recovery programmes, especially because predation may trap sparse prey pop...

  20. Chaotic behaviour of a predator-prey system

    NARCIS (Netherlands)

    Kooi, B.W.; Boer, M.P.

    2003-01-01

    Generally a predator-prey system is modelled by two ordinary differential equations which describe the rate of changes of the biomasses. Since such a system is two-dimensional no chaotic behaviour can occur. In the popular Rosenzweig-MacArthur model, which replaced the Lotka-Volterra model, a stable

  1. Permanence in Nonautonomous Predator-prey Lotka-Volterra Systems

    Institute of Scientific and Technical Information of China (English)

    Wu-jun Sun; Zhi-dong Teng; Yuan-hong Yu

    2002-01-01

    In this paper some easily verifiable sufficient conditions on the permanence of solutions for general nonautonomous two-species predator-prey model are established. These new criteria improve and extend the results given by Ma, Wang[3], Teng[4] and Teng, Yu[6].

  2. Numerical Solutions of a Fractional Predator-Prey System

    OpenAIRE

    Xin Baogui; Liu Yanqin

    2011-01-01

    We implement relatively new analytical technique, the Homotopy perturbation method, for solving nonlinear fractional partial differential equations arising in predator-prey biological population dynamics system. Numerical solutions are given, and some properties exhibit biologically reasonable dependence on the parameter values. And the fractional derivatives are described in the Caputo sense.

  3. Non-algebraic oscillations for predator-prey models

    OpenAIRE

    Ferragut, Antoni

    2014-01-01

    The authors are partially supported by grants MTM2008-03437 and 2009SGR-410. The first author is additionally partially supported by grants Juan de la Cierva and MTM2009-14163-C02-02. We prove that the limit cycle oscillations of the celebrated Rosenzweig-MacArthur differential system and other predator-prey models are non-algebraic.

  4. PERMANENCE OF A NONLINEAR DISCRETE PREDATOR-PREY SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Yaoping Chen; Fengde Chen

    2009-01-01

    In this paper,we study a nonlinear discrete predator-prey model. We obtain a set of sufficient conditions which guarantee the permanence of the system. And an example together with its numeric simulation is presented to show the feasibility of our result.

  5. Stabilization for a Periodic Predator-Prey System

    OpenAIRE

    Carmen Oana Tarniceriu; Sebastian Aniţa

    2007-01-01

    A reaction-diffusion system modelling a predator-prey system in a periodic environment is considered. We are concerned in stabilization to zero of one of the components of the solution, via an internal control acting on a small subdomain, and in the preservation of the nonnegativity of both components.

  6. Echolocating bats cry out loud to detect their prey

    DEFF Research Database (Denmark)

    Surlykke, Annemarie; Kalko, Elisabeth K V

    2008-01-01

    Echolocating bats have successfully exploited a broad range of habitats and prey. Much research has demonstrated how time-frequency structure of echolocation calls of different species is adapted to acoustic constraints of habitats and foraging behaviors. However, the intensity of bat calls has b...

  7. Global Dynamics of a Predator-prey Mo del

    Institute of Scientific and Technical Information of China (English)

    Huang Rui; Pan Qiang-you; Bao Lian-zhang; Wang Chun-peng

    2015-01-01

    In this paper, we consider a predator-prey model. A sufficient condition is presented for the stability of the equilibrium, which is different from the one for the model with Hassell-Varley type functional response. Furthermore, by constructing a Lyapunov function, we prove that the positive equilibrium is asymptotically stable.

  8. Direct identification of predator-prey dynamics in gyrokinetic simulations

    Science.gov (United States)

    Kobayashi, Sumire; Gürcan, Özgür D.; Diamond, Patrick H.

    2015-09-01

    The interaction between spontaneously formed zonal flows and small-scale turbulence in nonlinear gyrokinetic simulations is explored in a shearless closed field line geometry. It is found that when clear limit cycle oscillations prevail, the observed turbulent dynamics can be quantitatively captured by a simple Lotka-Volterra type predator-prey model. Fitting the time traces of full gyrokinetic simulations by such a reduced model allows extraction of the model coefficients. Scanning physical plasma parameters, such as collisionality and density gradient, it was observed that the effective growth rates of turbulence (i.e., the prey) remain roughly constant, in spite of the higher and varying level of primary mode linear growth rates. The effective growth rate that was extracted corresponds roughly to the zonal-flow-modified primary mode growth rate. It was also observed that the effective damping of zonal flows (i.e., the predator) in the parameter range, where clear predator-prey dynamics is observed, (i.e., near marginal stability) agrees with the collisional damping expected in these simulations. This implies that the Kelvin-Helmholtz-like instability may be negligible in this range. The results imply that when the tertiary instability plays a role, the dynamics becomes more complex than a simple Lotka-Volterra predator prey.

  9. Chaotic behaviour of a predator-prey system

    NARCIS (Netherlands)

    Kooi, B.W.; Boer, M.P.

    2003-01-01

    Generally a predator-prey system is modelled by two ordinary differential equations which describe the rate of changes of the biomasses. Since such a system is two-dimensional no chaotic behaviour can occur. In the popular Rosenzweig-MacArthur model, which replaced the Lotka-Volterra model, a stable

  10. Stochastic population oscillations in spatial predator-prey models

    Energy Technology Data Exchange (ETDEWEB)

    Taeuber, Uwe C, E-mail: tauber@vt.edu [Department of Physics, Virginia Tech, Blacksburg, VA 24061-0435 (United States)

    2011-09-15

    It is well-established that including spatial structure and stochastic noise in models for predator-prey interactions invalidates the classical deterministic Lotka-Volterra picture of neutral population cycles. In contrast, stochastic models yield long-lived, but ultimately decaying erratic population oscillations, which can be understood through a resonant amplification mechanism for density fluctuations. In Monte Carlo simulations of spatial stochastic predator-prey systems, one observes striking complex spatio-temporal structures. These spreading activity fronts induce persistent correlations between predators and prey. In the presence of local particle density restrictions (finite prey carrying capacity), there exists an extinction threshold for the predator population. The accompanying continuous non-equilibrium phase transition is governed by the directed-percolation universality class. We employ field-theoretic methods based on the Doi-Peliti representation of the master equation for stochastic particle interaction models to (i) map the ensuing action in the vicinity of the absorbing state phase transition to Reggeon field theory, and (ii) to quantitatively address fluctuation-induced renormalizations of the population oscillation frequency, damping, and diffusion coefficients in the species coexistence phase.

  11. Direct identification of predator-prey dynamics in gyrokinetic simulations

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Sumire, E-mail: sumire.kobayashi@lpp.polytechnique.fr; Gürcan, Özgür D [Laboratoire de Physique des Plasmas, CNRS, Paris-Sud, Ecole Polytechnique, UMR7648, F-91128 Palaiseau (France); Diamond, Patrick H. [University of California, San Diego, La Jolla, California 92093-0319 (United States)

    2015-09-15

    The interaction between spontaneously formed zonal flows and small-scale turbulence in nonlinear gyrokinetic simulations is explored in a shearless closed field line geometry. It is found that when clear limit cycle oscillations prevail, the observed turbulent dynamics can be quantitatively captured by a simple Lotka-Volterra type predator-prey model. Fitting the time traces of full gyrokinetic simulations by such a reduced model allows extraction of the model coefficients. Scanning physical plasma parameters, such as collisionality and density gradient, it was observed that the effective growth rates of turbulence (i.e., the prey) remain roughly constant, in spite of the higher and varying level of primary mode linear growth rates. The effective growth rate that was extracted corresponds roughly to the zonal-flow-modified primary mode growth rate. It was also observed that the effective damping of zonal flows (i.e., the predator) in the parameter range, where clear predator-prey dynamics is observed, (i.e., near marginal stability) agrees with the collisional damping expected in these simulations. This implies that the Kelvin-Helmholtz-like instability may be negligible in this range. The results imply that when the tertiary instability plays a role, the dynamics becomes more complex than a simple Lotka-Volterra predator prey.

  12. Prey capture and phagocytosis in the choanoflagellate Salpingoeca rosetta.

    Directory of Open Access Journals (Sweden)

    Mark J Dayel

    Full Text Available Choanoflagellates are unicellular and colonial aquatic microeukaryotes that capture bacteria using an apical flagellum surrounded by a feeding collar composed of actin-filled microvilli. Flow produced by the apical flagellum drives prey bacteria to the feeding collar for phagocytosis. We report here on the cell biology of prey capture in rosette-shaped colonies and unicellular "thecate" or substrate attached cells from the choanoflagellate S. rosetta. In thecate cells and rosette colonies, phagocytosis initially involves fusion of multiple microvilli, followed by remodeling of the collar membrane to engulf the prey, and transport of engulfed bacteria into the cell. Although both thecate cells and rosette colony cells produce ∼ 70 nm "collar links" that connect and potentially stabilize adjacent microvilli, only thecate cells were observed to produce a lamellipod-like "collar skirt" that encircles the base of the collar. This study offers insight into the process of prey ingestion by S. rosetta, and provides a context within which to consider potential ecological differences between solitary cells and colonies in choanoflagellates.

  13. How sailfish use their bills to capture schooling prey

    DEFF Research Database (Denmark)

    Domenici, P.; Wilson, A.D.M.; Kurvers, R.H.J.M.

    2014-01-01

    on prey. Here, we present the first unequivocal evidence of how the bill is used by Atlantic sailfish (Istiophorus albicans) to attack schooling sardines in the open ocean. Using high-speed video-analysis, we show that (i) sailfish manage to insert their bill into sardine schools without eliciting...

  14. Along Came a Spider: Using Live Arthropods in a Predator-Prey Activity

    Science.gov (United States)

    Richardson, Matthew L.; Hari, Janice

    2011-01-01

    We developed a predator-prey activity with eighth-grade students in which they used wolf spiders ("Lycosa carolinensis"), house crickets ("Acheta domestica"), and abiotic factors to address how (1) adaptations in predators and prey shape their interaction and (2) abiotic factors modify the interaction between predators and prey. We tested student…

  15. Sufficient and necessary condition for the permanence of periodic predator-prey system

    Directory of Open Access Journals (Sweden)

    Jingan Cui

    2004-01-01

    Full Text Available We consider the permanence of a periodic predator-prey system, where the prey disperse in a two-patch environment. We assume the Volterra within-patch dynamics and provide a sufficient and necessary condition to guarantee the predator and prey species to be permanent by using the techniques of inequality analysis. Our work improves previous relevant results.

  16. Nonselective Harvesting of a Prey-Predator Fishery with Gompertz Law of Growth

    Science.gov (United States)

    Purohit, D.; Chaudhuri, K. S.

    2002-01-01

    This paper develops a mathematical model for the nonselective harvesting of a prey-predator system in which both the prey and the predator obey the Gompertz law of growth and some prey avoid predation by hiding. The steady states of the system are determined, and the dynamical behaviour of both species is examined. The possibility of existence of…

  17. Irreversible prey diapause as an optimal strategy of a physiologically extended Lotka-Volterra model

    NARCIS (Netherlands)

    Staňková, K.; Abate, A.; Sabelis, M.W.

    2013-01-01

    We propose an optimal control framework to describe intra-seasonal predator-prey interactions, which are characterized by a continuous-time dynamical model comprising predator and prey density, as well as the energy budget of the prey over the length of a season. The model includes a time-dependent

  18. Irreversible prey diapause as an optimal strategy of a physiologically extended Lotka-Volterra model

    NARCIS (Netherlands)

    K. Staňková; A. Abate; M.W. Sabelis

    2013-01-01

    We propose an optimal control framework to describe intra-seasonal predator-prey interactions, which are characterized by a continuous-time dynamical model comprising predator and prey density, as well as the energy budget of the prey over the length of a season. The model includes a time-dependent

  19. Marine predators and persistent prey in the southeast Bering Sea

    Science.gov (United States)

    Sigler, Michael F.; Kuletz, Kathy J.; Ressler, Patrick H.; Friday, Nancy A.; Wilson, Christopher D.; Zerbini, Alexandre N.

    2012-06-01

    Predictable prey locations reduce search time and energetic costs of foraging; thus marine predators often exploit locations where prey concentrations persist. In our study, we examined whether this association is influenced by differences among predator species in foraging modes (travel cost, surface feeder or diver) or whether the predator species is a central place forager or not. We examined distributions of two seabird species during their nesting period, the surface-feeding black-legged kittiwake (Rissa tridactyla) and the pursuit-diving thick-billed murre (Uria lomvia), and two baleen whale species, the humpback whale (Megaptera novaeangliae) and the fin whale (Balaenoptera physalus), in relation to two key prey, age-1 walleye pollock (Theragra chalcogramma) and euphausiids (Euphausiidae). Prey surveys were conducted once each year during 2004 and 2006-2010. Concurrent predator surveys were conducted in 2006-2010 (seabirds) and 2008 and 2010 (whales). We compared the seabird and whale foraging locations to where age-1 pollock and euphausiids were concentrated and considered the persistence of these concentrations, where the time-scale of persistence is year (i.e., a comparison among surveys that are conducted once each year). Euphausiids were widespread and concentrations often were reliably found within specific 37 km×37 km blocks ('persistent hot spots of prey'). In contrast, age-1 pollock were more concentrated and their hot spots were persistent only on coarser scales (>37 km). Both seabird species, regardless of foraging mode, were associated with age-1 pollock but not with euphausiids, even though age-1 pollock were less persistent than euphausiids. The higher travel cost central place foragers, thick-billed murres, foraged at prey concentrations nearer their island colonies than black-legged kittiwakes, which were more widespread foragers. Humpback whales were not tied to a central place and mostly were located only where euphausiids were

  20. Permanence and global attractivity of stage-structured predator-prey model with continuous harvesting on predator and impulsive stocking on prey

    Institute of Scientific and Technical Information of China (English)

    JIAO Jian-jun; CHEN Lan-sun; Juan J. Nieto; Torres Angela

    2008-01-01

    We investigate a stage-structured delayed predator-prey model with impulsive stocking on prey and continuous harvesting on predator. According to the fact of biological resource management, we improve the assumption of a predator-prey model with stage structure for predator population that each individual predator has the same ability to capture prey. It is assumed that the immature and mature individuals of the predator population are divided by a fixed age, and immature predator population does not have the ability to attach prey. Sufficient conditions are obtained, which guarantee the global attractivity of predator-extinction periodic solution and the permanence of the system. Our results show that the behavior of impulsive stocking on prey plays an important role for the permanence of the system, and provide tactical basis for the biological resource management. Numerical analysis is presented to illuminate the dynamics of the system.

  1. Biological conservation of a prey-predator system incorporating constant prey refuge through provision of alternative food to predators: a theoretical study.

    Science.gov (United States)

    Chakraborty, Kunal; Das, Sankha Subhra

    2014-06-01

    We describe a prey-predator system incorporating constant prey refuge through provision of alternative food to predators. The proposed model deals with a problem of non-selective harvesting of a prey-predator system in which both the prey and the predator species obey logistic law of growth. The long-run sustainability of an exploited system is discussed through provision of alternative food to predators. We have analyzed the variability of the system in presence of constant prey refuge and examined the stabilizing effect on predator-prey system. The steady states of the system are derived and dynamical behavior of the system is extensively analyzed around steady states. The optimal harvesting policy is formulated and solved with the help of Pontryagin's maximal principle. Our objective is to maximize the monetary social benefit through protecting the predator species from extinction, keeping the ecological balance. Results finally illustrated with the help of numerical examples.

  2. Understanding spatial distributions : Negative density-dependence in prey causes predators to trade-off prey quantity with quality

    NARCIS (Netherlands)

    Bijleveld, Allert I; MacCurdy, Robert B; Chan, Ying-Chi; Penning, Emma; Gabrielson, Rich M; Cluderay, John; Spaulding, Eric L; Dekinga, Anne; Holthuijsen, Sander; ten Horn, Job; Brugge, Maarten; van Gils, Jan A; Winkler, David W; Piersma, Theunis

    2016-01-01

    Negative density-dependence is generally studied within a single trophic level, thereby neglecting its effect on higher trophic levels. The 'functional response' couples a predator's intake rate to prey density. Most widespread is a type II functional response, where intake rate increases asymptotic

  3. Understanding spatial distributions: negative density-dependence in prey causes predators to trade-off prey quantity with quality

    NARCIS (Netherlands)

    Bijleveld, A.I.; MacCurdy, R.B.; Chan, Y.-C; Penning, E.; Gabrielson, R.M.; Cluderay, J.; Spaulding, E.L.; Dekinga, A.; Holthuijsen, S.; Ten Horn, J.; Brugge, M.; van Gils, J.A.; Winkler, D.W.; Piersma, T.

    2016-01-01

    Negative density-dependence is generally studied within a single trophic level, thereby neglecting its effect on higher trophic levels. The ‘functional response’ couples a predator's intake rate to prey density. Most widespread is a type II functional response, where intake rate increases asymptotic

  4. Understanding spatial distributions: negative density-dependence in prey causes predators to trade-off prey quantity with quality

    NARCIS (Netherlands)

    Bijleveld, A.I.; MacCurdy, R.B.; Chan, Y.-C; Penning, E.; Gabrielson, R.M.; Cluderay, J.; Spaulding, E.L.; Dekinga, A.; Holthuijsen, S.; Ten Horn, J.; Brugge, M.; van Gils, J.A.; Winkler, D.W.; Piersma, T.

    2016-01-01

    Negative density-dependence is generally studied within a single trophic level, thereby neglecting its effect on higher trophic levels. The ‘functional response’ couples a predator's intake rate to prey density. Most widespread is a type II functional response, where intake rate increases

  5. Interactive effects of prey refuge and additional food for predator in a diffusive predator-prey system

    DEFF Research Database (Denmark)

    Chakraborty, Subhendu; Tiwari, P. K.; Sasmal, S.K.

    2017-01-01

    Additional food for predators has been considered as one of the best established techniques in integrated pest management and biological conservation programs. In natural systems, there are several other factors, e.g., prey refuge, affect the success of pest control. In this paper, we analyze a p...

  6. Impact of cannibalism on predator-prey dynamics: size-structured interactions and apparent mutualism.

    Science.gov (United States)

    Rudolf, Volker H W

    2008-06-01

    Direct and indirect interactions between two prey species can strongly alter the dynamics of predator-prey systems. Most predators are cannibalistic, and as a consequence, even systems with only one predator and one prey include two prey types: conspecifics and heterospecifics. The effects of the complex direct and indirect interactions that emerge in such cannibalistic systems are still poorly understood. This study examined how the indirect interaction between conspecific and heterospecific prey affects cannibalism and predation rates and how the direct interactions between both species indirectly alter the effect of the cannibalistic predator. I tested for these effects using larvae of the stream salamanders Eurycea cirrigera (prey) and Pseudotriton ruber (cannibalistic predator) by manipulating the relative densities of the conspecific and heterospecific prey in the presence and absence of the predator in experimental streams. The rates of cannibalism and heterospecific predation were proportional to the respective densities and negatively correlated, indicating a positive indirect interaction between conspecific and heterospecific prey, similar to "apparent mutualism." Direct interactions between prey species did not alter the effect of the predator. Although both types of prey showed a similar 30% reduction in night activity and switch in microhabitat use in response to the presence of the predator, cannibalism rates were three times higher than heterospecific predation rates irrespective of the relative densities of the two types of prey. Cumulative predation risks differed even more due to the 48% lower growth rate of conspecific prey. Detailed laboratory experiments suggest that the 3:1 difference in cannibalism and predation rate was due to the higher efficiency of heterospecific prey in escaping immediate attacks. However, no difference was observed when the predator was a closely related salamander species, Gyrinophilus porphyriticus, indicating that

  7. Preference and Prey Switching in a Generalist Predator Attacking Local and Invasive Alien Pests

    Science.gov (United States)

    Jaworski, Coline C.; Bompard, Anaïs; Genies, Laure; Amiens-Desneux, Edwige; Desneux, Nicolas

    2013-01-01

    Invasive pest species may strongly affect biotic interactions in agro-ecosystems. The ability of generalist predators to prey on new invasive pests may result in drastic changes in the population dynamics of local pest species owing to predator-mediated indirect interactions among prey. On a short time scale, the nature and strength of such indirect interactions depend largely on preferences between prey and on predator behavior patterns. Under laboratory conditions we evaluated the prey preference of the generalist predator Macrolophus pygmaeus Rambur (Heteroptera: Miridae) when it encounters simultaneously the local tomato pest Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) and the invasive alien pest Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae). We tested various ratios of local vs. alien prey numbers, measuring switching by the predator from one prey to the other, and assessing what conditions (e.g. prey species abundance and prey development stage) may favor such prey switching. The total predation activity of M. pygmaeus was affected by the presence of T. absoluta in the prey complex with an opposite effect when comparing adult and juvenile predators. The predator showed similar preference toward T. absoluta eggs and B. tabaci nymphs, but T. absoluta larvae were clearly less attacked. However, prey preference strongly depended on prey relative abundance with a disproportionately high predation on the most abundant prey and disproportionately low predation on the rarest prey. Together with the findings of a recent companion study (Bompard et al. 2013, Population Ecology), the insight obtained on M. pygmaeus prey switching may be useful for Integrated Pest Management in tomato crops, notably for optimal simultaneous management of B. tabaci and T. absoluta, which very frequently co-occur on tomato. PMID:24312646

  8. Genomics and proteomics of immune modulatory effects of a butanol fraction of echinacea purpurea in human dendritic cells

    Directory of Open Access Journals (Sweden)

    Hwang Pei-Ing

    2008-10-01

    Full Text Available Abstract Background Echinacea spp. extracts and the derived phytocompounds have been shown to induce specific immune cell activities and are popularly used as food supplements or nutraceuticals for immuno-modulatory functions. Dendritic cells (DCs, the most potent antigen presenting cells, play an important role in both innate and adaptive immunities. In this study, we investigated the specific and differential gene expression in human immature DCs (iDCs in response to treatment with a butanol fraction containing defined bioactive phytocompounds extracted from stems and leaves of Echinacea purpurea, that we denoted [BF/S+L/Ep]. Results Affymetrix DNA microarray results showed significant up regulation of specific genes for cytokines (IL-8, IL-1β, and IL-18 and chemokines (CXCL 2, CCL 5, and CCL 2 within 4 h after [BF/S+L/Ep] treatment of iDCs. Bioinformatics analysis of genes expressed in [BF/S+L/Ep]-treated DCs revealed a key-signaling network involving a number of immune-modulatory molecules leading to the activation of a downstream molecule, adenylate cyclase 8. Proteomic analysis showed increased expression of antioxidant and cytoskeletal proteins after treatment with [BF/S+L/Ep] and cichoric acid. Conclusion This study provides information on candidate target molecules and molecular signaling mechanisms for future systematic research into the immune-modulatory activities of an important traditional medicinal herb and its derived phytocompounds.

  9. A resurrection experiment finds evidence of both reduced genetic diversity and potential adaptive evolution in the agricultural weed Ipomoea purpurea.

    Science.gov (United States)

    Kuester, Adam; Wilson, Ariana; Chang, Shu-Mei; Baucom, Regina S

    2016-09-01

    Despite the negative economic and ecological impact of weeds, relatively little is known about the evolutionary mechanisms that influence their persistence in agricultural fields. Here, we use a resurrection approach to examine the potential for genotypic and phenotypic evolution in Ipomoea purpurea, an agricultural weed that is resistant to glyphosate, the most widely used herbicide in current-day agriculture. We found striking reductions in allelic diversity between cohorts sampled nine years apart (2003 vs. 2012), suggesting that populations of this species sampled from agricultural fields have experienced genetic bottleneck events that have led to lower neutral genetic diversity. Heterozygosity excess tests indicate that these bottlenecks may have occurred prior to 2003. A greenhouse assay of individuals sampled from the field as seed found that populations of this species, on average, exhibited modest increases in herbicide resistance over time. However, populations differed significantly between sampling years for resistance: some populations maintained high resistance between the sampling years whereas others exhibited increased or decreased resistance. Our results show that populations of this noxious weed, capable of adapting to strong selection imparted by herbicide application, may lose genetic variation as a result of this or other environmental factors. We probably uncovered only modest increases in resistance on average between sampling cohorts due to a strong and previously identified fitness cost of resistance in this species, along with the potential that nonresistant migrants germinate from the seed bank.

  10. A comparative study on rooting of in vitro regenerated shoots in haploid, diploid and tetraploid purple coneflower (Echinacea purpurea L.

    Directory of Open Access Journals (Sweden)

    Rong Chen

    2016-01-01

    Full Text Available Haploid, diploid and tetraploid shoots of Echinacea purpurea L. sharing the same genome were cultured in medium and their rooting response to the composition of the culture medium was investigated. It was found that in medium without growth regulators, haploid shoots could initiate roots quite efficiently with the shortest time required for the emergence of roots and with the highest rooting rate; the response of the diploids was similar to that of the haploids and largely different from that of the tetraploids. The tetraploids obviously required longer time for the initiation of roots and had the lowest rooting rate. Supplementing the medium with 0.05 and 0.15 mg/L naphthaleneacetic acid or 0.1 and 0.3 mg/L indole-3-butyric acid (IBA had little positive effect on the rooting of diploid shoots and, in some cases, had even negative effect on the rooting of haploid shoots, but enhanced effectively the rooting of the tetraploid shoots. By supplementing the medium with 0.3 mg/L IBA, the time required for the emergence of roots from the tetraploid shoots was shortened and the rooting rate was increased largely. As a result, healthy tetraploid plantlets with fully developed root system could be efficiently propagated.

  11. Transformación genética de Echinacea purpurea y E. angustifolia mediante Agrobacterium rhizogenes

    Directory of Open Access Journals (Sweden)

    Jorge Loaiza

    2006-01-01

    Full Text Available Secciones de tallos de vitroplántulas de Echinacea purpurea y E. angustifolia fueron inoculadas con Agrobacterium rhizogenes cepa SV3101, con la finalidad de obtener plántulas transformadas. Se evaluó el efecto de la acetosiringona en combinación con floroglucinol sobre la transformación. El proceso de transformación aumentó proporcional y significativamente conforme se incrementó las concentraciones de ambos productos; llegándose a obtener un 100% de trasformación cuando se usó 200 μM de acetosiringona en combinación con 50 mg l –1 de floroglucinol. La eliminación de la bacteria se logró con 6 ml l-1 del Plant Preservative Mixture (PPM. También, se logró el cultivo in vitro de sólo raíces trasformadas, las cuales incrementaron su peso seco 11 veces en un periodo de 24 días de cultivo, momento en el cual se hace necesario iniciar un nuevo cultivo.

  12. Impact of UV-B radiation on some biochemical changes and growth parameters in Echinacea purpurea callus and suspension culture

    Directory of Open Access Journals (Sweden)

    Hossam H. Manaf

    2016-12-01

    Full Text Available The effects of UV-B light force, exposure time and incubation period on producing caffeic acid derivatives and growth parameters in Echinacea purpurea callus and suspension culture were assessed. UV-B led to an increment of all growth parameters and antioxidant activity in callus and cell suspension and caffeic acid derivatives in cell suspension by increasing incubation period. The reverse was true for G-POD activity in cell suspension and PAL activity in both types of cultures. Incubation period 2 weeks was more effective in caffeic acid, total phenols and G-POD activity in callus cells and incubation period one week only for total phenols in cell suspension. The two exposure times 2 and 4 h increased antioxidant activity in the two types of cultures. Exposure time 2 h led to increase caffeic acid and total phenols in callus cells. The maximum increase in caffeic acid, total phenols and PAL activity in cell suspension was achieved by 4 h exposure time. Likewise, using 2 UV-B lamps for 2 h was the most effective in creating more biochemical components than the other treatments.

  13. Evaluation of Different Levels of Nitrogen and Phosphorus Fertilizers on Shoot and Root Characteristics of Echinacea purpurea

    Directory of Open Access Journals (Sweden)

    morteza Goldani

    2017-02-01

    Full Text Available Introduction: Purple coneflower with scientific name Echinacea purpurea (L. is an herbaceous perennial plant native to North America and is the one of the most important medicinal plants in the world. Root of Echinacea purpurea is commonly used around the world for stimulation of immune system. It is used as herbal medicine in respiratory infections, against malignant tumors and several inflammatory conditions However, nitrogen and phosphorus are the main elements that make up the proteins in plants and herbs for natural growth, especially is necessary in their productive organs. The results showed that nitrogen and phosphorus are important in continuation of flowering, the flowers fresh and dry weight and in essential oil. Fertilization of E. purpurea plants indicated that in absence or at low levels of nitrogen fertilization (0 and 100 kg acre-1, the addition of 50 and 100 kg acre-1 of potassium increased aerial parts, flower heads and root yield. Another report indicated that highest aerial biomass and root yield in E. purpurea was obtained with 100 kg ha-1 of nitrogen at constant rates of phosphorus and potassium. Polyphenol content was not influenced by nitrogen fertilization and values fluctuated between 2.4 and 5.4 % in the aerial part at flowering and between 1.6 and 3.5 % in the roots. Fertilization with nitrogen caused a decrease in the concentrations of echinoside. Echinoside content was 1.16 % without nitrogen fertilization, and 0.94 % with nitrogen fertilization. Materials and Methods: To evaluate the effect of different levels of nitrogen and phosphorus on growth and yield of coneflower, a factorial experiment in a completely randomized design with three replications was conducted in Ferdowsi University of Mashhad. Treatments were included three levels of nitrogen (0, 1 and 2 gr urea per kilogram of soil and three levels of phosphate fertilizer (0, 0.75 and 1.5 gr of phosphate (P2O5 per kg of soil. Nitrogen fertilizer was applied

  14. Effect of oral administration of freshly pressed juice of Echinacea purpurea on the number of various subpopulations of B- and T-lymphocytes in healthy volunteers: results of a double-blind, placebo-controlled cross-over study

    DEFF Research Database (Denmark)

    Schwarz, Evelyn; Parlesak, Alexandr; Henneicke-von-Zeppelin, H. H.;

    2005-01-01

    BACKGROUND: In a recent double-blind placebo-controlled crossover-study the "immune stimulatory" effects (activation of macrophages leading to enhanced phagocytosis and production of several cytokines) of Echinacea purpurea preparations (EPP) which were observed in vitro experiments and following......-40 years) participated in the study. They received either a commercially available pressed juice of E. purpurea herbs or placebo juice using a double-blind placebo-controlled cross-over design with two treatment periods of 14 days. The total number of lymphocytes and 12 subgroups of lymphocytes were...

  15. Effect of Prey Refuge on the Spatiotemporal Dynamics of a Modified Leslie-Gower Predator-Prey System with Holling Type III Schemes

    Directory of Open Access Journals (Sweden)

    Hengguo Yu

    2013-06-01

    Full Text Available In this paper, the spatiotemporal dynamics of a diffusive Leslie-Gower predator-prey model with prey refuge are investigated analytically and numerically. Mathematical theoretical works have considered the existence of global solutions, population permanence and the stability of equilibrium points, which depict the threshold expressions of some critical parameters. Numerical simulations are performed to explore the pattern formation of species. These results show that the prey refuge has a profound effect on predator-prey interactions and they have the potential to be useful for the study of the entropy theory of bioinformatics.

  16. The global stability of a delayed predator-prey system with two stage-structure

    Energy Technology Data Exchange (ETDEWEB)

    Wang Fengyan [College of Science, Jimei University, Xiamen Fujian 361021 (China)], E-mail: wangfy68@163.com; Pang Guoping [Department of Mathematics and Computer Science, Yulin Normal University, Yulin Guangxi 537000 (China)

    2009-04-30

    Based on the classical delayed stage-structured model and Lotka-Volterra predator-prey model, we introduce and study a delayed predator-prey system, where prey and predator have two stages, an immature stage and a mature stage. The time delays are the time lengths between the immature's birth and maturity of prey and predator species. Results on global asymptotic stability of nonnegative equilibria of the delay system are given, which generalize and suggest that good continuity exists between the predator-prey system and its corresponding stage-structured system.

  17. Foraging success of juvenile pike Esox lucius depends on visual conditions and prey pigmentation.

    Science.gov (United States)

    Jönsson, M; Hylander, S; Ranåker, L; Nilsson, P A; Brönmark, C

    2011-07-01

    Young-of-the-year pike Esox lucius foraging on copepods experienced different foraging success depending on prey pigmentation in water visually degraded by brown colouration or algae. Both attack rate and prey consumption rate were higher for E. lucius foraging on transparent prey in brown water, whereas the opposite was true in algal turbid water. Pigments in copepod prey may have a cryptic function in brown water instead of a photo-protective function even if prey-size selectivity was stronger than selection based on pigmentation in juvenile E. lucius.

  18. Prey preferences of the snow leopard (Panthera uncia: regional diet specificity holds global significance for conservation.

    Directory of Open Access Journals (Sweden)

    Salvador Lyngdoh

    Full Text Available The endangered snow leopard is a large felid that is distributed over 1.83 million km(2 globally. Throughout its range it relies on a limited number of prey species in some of the most inhospitable landscapes on the planet where high rates of human persecution exist for both predator and prey. We reviewed 14 published and 11 unpublished studies pertaining to snow leopard diet throughout its range. We calculated prey consumption in terms of frequency of occurrence and biomass consumed based on 1696 analysed scats from throughout the snow leopard's range. Prey biomass consumed was calculated based on the Ackerman's linear correction factor. We identified four distinct physiographic and snow leopard prey type zones, using cluster analysis that had unique prey assemblages and had key prey characteristics which supported snow leopard occurrence there. Levin's index showed the snow leopard had a specialized dietary niche breadth. The main prey of the snow leopard were Siberian ibex (Capra sibrica, blue sheep (Pseudois nayaur, Himalayan tahr (Hemitragus jemlahicus, argali (Ovis ammon and marmots (Marmota spp. The significantly preferred prey species of snow leopard weighed 55±5 kg, while the preferred prey weight range of snow leopard was 36-76 kg with a significant preference for Siberian ibex and blue sheep. Our meta-analysis identified critical dietary resources for snow leopards throughout their distribution and illustrates the importance of understanding regional variation in species ecology; particularly prey species that have global implications for conservation.

  19. The benefits of being toxic to deter predators depends on prey body size

    Science.gov (United States)

    Smith, Karen E.; Halpin, Christina G.

    2016-01-01

    Many prey have evolved toxins as a defense against predation. Those species that advertise their toxicity to would-be predators with conspicuous warning signals are known as “aposematic.” Investment in toxicity by aposematically signaling prey is thought to underpin how aversive prey are to predators; increasing toxicity means that predators learn to avoid prey faster and attack them at lower rates. However, predators’ foraging decisions on aposematic prey are determined not only by their toxicity, but also by their nutrient content: predators can trade-off the costs of ingesting toxin with the benefits of acquiring nutrients. Prey body size is a cue that positively correlates with nutrient content, and that varies within and between aposematic species. We predicted that a dose of quinine (known to be toxic to birds) would be a more effective deterrent to avian predators when prey were small compared with when they were large, and that the benefits of possessing toxin would be greater for small-bodied prey. Using an established laboratory protocol of European starlings (Sturnus vulgaris) foraging on mealworms (Tenebrio molitor), we found evidence for increased protection from a dose of quinine for small-bodied compared with large-bodied prey. This shows that larger prey need more toxin to attain the same level of defense as smaller prey, which has implications for the evolution of aposematism and mimicry. PMID:28028378

  20. Sabretoothed carnivores and the killing of large prey.

    Directory of Open Access Journals (Sweden)

    Ki Andersson

    Full Text Available Sabre-like canines clearly have the potential to inflict grievous wounds leading to massive blood loss and rapid death. Hypotheses concerning sabretooth killing modes include attack to soft parts such as the belly or throat, where biting deep is essential to generate strikes reaching major blood vessels. Sabretoothed carnivorans are widely interpreted as hunters of larger and more powerful prey than that of their present-day nonsabretoothed relatives. However, the precise functional advantage of the sabretooth bite, particularly in relation to prey size, is unknown. Here, we present a new point-to-point bite model and show that, for sabretooths, depth of the killing bite decreases dramatically with increasing prey size. The extended gape of sabretooths only results in considerable increase in bite depth when biting into prey with a radius of less than ∼10 cm. For sabretooths, this size-reversed functional advantage suggests predation on species within a similar size range to those attacked by present-day carnivorans, rather than "megaherbivores" as previously believed. The development of the sabretooth condition appears to represent a shift in function and killing behaviour, rather than one in predator-prey relations. Furthermore, our results demonstrate how sabretoothed carnivorans are likely to have evolved along a functionally continuous trajectory: beginning as an extension of a jaw-powered killing bite, as adopted by present-day pantherine cats, followed by neck-powered biting and thereafter shifting to neck-powered shear-biting. We anticipate this new insight to be a starting point for detailed study of the evolution of pathways that encompass extreme specialisation, for example, understanding how neck-powered biting shifts into shear-biting and its significance for predator-prey interactions. We also expect that our model for point-to-point biting and bite depth estimations will yield new insights into the behaviours of a broad range of

  1. Prey selection of Tawny owls (Strix aluco) on Yellow necked mouse and Bank Vole

    DEFF Research Database (Denmark)

    Forsom, H. M.; Sunde, P.; Overskaug, K.

    As predators owls may have a strong impact on mortality of their favourite prey, and may therefore act as important selective agents on their prey species. Little is known, however, about whether owls choose prey randomly or if some prey items suffer a higher risk of predation due to certain life...... history traits. The aim of this master thesis study was to investigate any prey selection of tawny owls on two prey species, yellow-necked mouse (Apodemus flavicollis) and bank voles (Clethrionomys glareolus). Our hypotheses were that the level of exposure might differ between prey items of different sex......, age, and size, causing some individuals to suffer a higher risk of predation from tawny owls than others.The results suggest that males suffer a higher risk of predation from tawny owls than females, and that the different age groups may also experience different risk of predation. It also suggests...

  2. Effects of prey density on the growth and survival of hybrid snakehead larvae

    Institute of Scientific and Technical Information of China (English)

    Wenkui LIU; Qixue FAN; Bangke ZHU; Haiming DU; Xigang FENG

    2008-01-01

    The effects of prey density (0.1, 0.3, 1, 3 and snakehead (Channa argus × C. maculate) larvae were investigated. The larvae were divided into three groups with different body lengths of 0.68 cm, 1.50 cm and 3.20 cm, respectively. The growth of the hybrid snake-head larvae in all three groups increased with prey growth rate (SGR) was the highest when the prey density early development stage) decreased, while no significant change was observed in those of Group Ⅱ and Group Ⅲ. The survival rates of hybrid snakehead larvae in all three groups were high (91.11%-100%) and not significantly affected by the prey densities except in Group Ⅰ with the significantly lower than the others. Body size was not sensitive to prey density. The optimum prey density was confirmed at 1 prey·mL-1 in all the treatments.

  3. Expression of Stipa purpurea SpCIPK26 in Arabidopsis thaliana Enhances Salt and Drought Tolerance and Regulates Abscisic Acid Signaling

    Directory of Open Access Journals (Sweden)

    Yanli Zhou

    2016-06-01

    Full Text Available Stipa purpurea (S. purpurea is the dominant plant species in the alpine steppe of the Qinghai-Tibet Plateau, China. It is highly resistant to cold and drought conditions. However, the underlying mechanisms regulating the stress tolerance are unknown. In this study, a CIPK gene from S. purpurea (SpCIPK26 was isolated. The SpCIPK26 coding region consisted of 1392 bp that encoded 464 amino acids. The protein has a highly conserved catalytic structure and regulatory domain. The expression of SpCIPK26 was induced by drought and salt stress. SpCIPK26 overexpression in Arabidopsis thaliana (A. thaliana plants provided increased tolerance to drought and salt stress in an abscisic acid (ABA-dependent manner. Compared with wild-type A. thaliana plants, SpCIPK26-overexpressing plants had higher survival rates, water potentials, and photosynthetic efficiency (Fv/Fm, as well as lower levels of reactive oxygen species (ROS following exposure to drought and salt stress. Gene expression analyses indicated stress-inducible genes (RD29A, RD29B, and ABF2 and a ROS-scavenger gene (CAT1 were upregulated in SpCIPK26-overexpressing plants after stress treatments. All of these marker genes are associated with ABA-responsive cis-acting elements. Additionally, the similarities in the gene expression patterns following ABA, mannitol, and NaCl treatments suggest SpCIPK26 has an important role during plant responses to drought and salt stress and in regulating ABA signaling.

  4. The effect of Echinacea purpurea aerial organ dried extract vs. Zinc oxide on skin wound healing in rat: a morphometric & histopathologic study

    Directory of Open Access Journals (Sweden)

    Delazar A

    2008-12-01

    Full Text Available "nBackground: Because of eventual side effects of chemical drugs, the efficacy of natural wound healing accelerators in long-term diseases and some situations is demanded to practitioners. The initial aim of our study was to assess full thickness excisional skin wound healing and inflammation diminution, Morphometrically and Histopathologically, after topical application of dried extract of Echinacea purpurea aerial part in rats, compared with zinc oxide. "nMethods: Sixty wistar rats received four full thickness excisional wounds with the aim of surgical punch on the back skin under surgical anesthesia. All rats were randomly divided into groups 1, 2 and 3, of Echinacea purpurea, zinc oxide and control, respectively. All of them were treated topically once a day for 21 uninterrupted days. Healing of the wounds was daily measured by taking digital photographs and analysis. Histopathologic assessment was carried out in the 0th, 3rd, 7th, 14th, and 21st days of treatment period as well, and wound healing was assessed using 1 to 6 healing grades. "nResults: According to Morphometric findings, the wound contraction rate in group 1 after 21 days of skin punching, with wound size of 0.18±0.03 mm2 in contrast with group 2, 2.81±0.21mm2, was much higher than that in other groups. Group 1 with wound contraction rate of 2.5 times in the day 7 and 3 times in the day 14 more than group 2, had the best wound contraction (p<0.01. histopathologic assessment revealed that, overall healing rate in the group 1 was highest (p<0.01. "nConclusion: Echinacea purpurea dried herbal extract could be a new capable remedy to accelerate skin wound healing because of its potential anti-phlogosis and wound healing stimulatory properties.

  5. A sensitive LC-MS/MS method for the quantitative analysis of the Echinacea purpurea constituent undeca-2-ene-8,10-diynoic acid isobutylamide in human plasma.

    Science.gov (United States)

    Goey, Andrew K L; Sparidans, Rolf W; Meijerman, Irma; Rosing, Hilde; Schellens, Jan H M; Beijnen, Jos H

    2011-01-01

    Echinacea purpurea is one of the most popular herbal medicines and is known for its immunostimulatory effects. Alkylamides are the main lipophilic components of E. purpurea that contribute to its pharmacological actions. For quantification in human plasma of one of these alkylamides, undeca-2-ene-8,10-diynoic acid isobutylamide, a sensitive LC-MS/MS assay has been developed and validated. Plasma samples were pretreated using liquid-liquid extraction with a mixture of diethyl ether and n-hexane (50:50, v/v). Dried extracts were reconstituted in 50 μL of acetonitrile-water (50:50, v/v) after which 15 μL of sample was injected into the HPLC system. HPLC was performed using a Polaris 3 C18-A column (50 mm×2 mm ID) and isocratic elution with acetonitrile-water (50:50, v/v) containing 0.1% formic acid at a flow rate of 0.3 mL/min. Subsequently, electrospray ionization in the positive ion mode followed by tandem mass spectrometry was performed for detection. The total run time was 3 min. The assay was validated over a concentration range from 0.05 to 50 ng/mL for undeca-2-ene-8,10-diynoic acid isobutylamide, with 0.05 ng/mL being the lower limit of quantification using 1.0 mL plasma samples. Inter-assay inaccuracy (±12.7%), within-day and between-day precisions (CV≤8.23%) were acceptable. Further, undeca-2-ene-8,10-diynoic acid isobutylamide was found to be chemically stable under relevant conditions. Finally, the applicability of this assay has been successfully demonstrated in a pharmacokinetic experiment in which a human volunteer ingested a commercial extract of E. purpurea. Copyright © 2010 Elsevier B.V. All rights reserved.

  6. Effect of hydroalcoholic extract of Echinacea purpurea in combination with meglumine antimoniate on treatment of Leishmania major-induced cutaneous leishmaniasis in BALB/c mice.

    Science.gov (United States)

    Sarkari, Bahador; Mohseni, Mobin; Moein, Mahmoud Reza; Shahriarirad, Reza; Asgari, Qasem

    2017-01-01

    Progressive resistance of Leishmania parasite to available drugs including, meglumine antimoniate, has been reported from various regions of the world, especially Iran. This study was conducted to evaluate the effect of hydroalcoholic extract of Echinacea purpurea in a combination therapy with glucantime in the treatment of cutaneous leishmaniasis caused by Leishmania major. Hydroalcoholic extract of E. purpurea was prepared from the plant. Amastigote form of L. major was inoculated to the tail base of thirty mice. After their tails became wounded, mice were divided into six groups. The first group was used as control and the second group received 100 mg/kg of Echinacea extract (orally). The third group was treated by meglumine antimoniate with dose of 20 mg/kg. Combination therapy was used for group four, five, and six where the mice received a different concentration of extract (100-200 mg/kg) and glucantime (10-20 mg/kg). The size of the cutaneous lesion on tail base was measured regularly. Findings were analyzed by SPSS software and using Kruskal-Wallis test. The sizes of the lesion were increased in all mice of control group by the time. The mean size of lesions in mice receiving the extract and/or receiving the extract along with meglumine antimoniate was lower than those of control mice, but the differences were not statistically significant (P > 0.05). On the other hand, the differences between the group of mice which received meglumine antimoniate alone, and the rest of groups were statistically significant (P purpurea extract in doses which have been used in this study and combination with meglumine antimoniate was not much effective against L. major in BALB/C mice.

  7. Evaluation of chemical parameters and ecotoxicity of a soil developed on gossan following application of polyacrylates and growth of Spergularia purpurea.

    Science.gov (United States)

    Santos, Erika S; Abreu, Maria Manuela; de Varennes, Amarilis; Macías, Felipe; Leitão, Sara; Cerejeira, Maria José

    2013-09-01

    The aim of this study was to evaluate the chemical characteristics and ecotoxicity of a mine soil developed on gossan materials and amended with hydrophilic polyacrylate polymers after a growth cycle of Spergularia purpurea. Different acute bioassays (Daphnia magna immobilization; microalgae growth inhibition; germination and growth of lettuce and oat) were carried out with simulated leachates, pore water and soil samples. The germination and growth of native shrubs (Cistus ladanifer and Lavandula sampaioana) were also evaluated in the lysimeters where S. purpurea had grown. The soil had high total concentrations (g/kg) of Al (3.50-8.60), As (2.55-2.73), Cu (0.13-0.91) and Pb (4.48-6.16). However, the percentages of elements in aqueous extracts (simulating leachates, pore water, and the conditions of the rhizosphere soil) were small when compared to their total soil concentrations (less than 9% except for Na in leachates). Growth of S. purpurea and other natural colonization of plant species (Poaceae, Fabaceae and Asteraceae families) improved chemical characteristics but the application of the polyacrylate polymers contributed to a further improvement of soil quality. However, this was not sufficient to ensure the growth of a large number of shrubs despite a great germination rate. Among the several species used on the ecotoxicological assessment, the D. magna test was the only bioassay that showed a clear toxicity of soil leachates, suggesting the importance of using several ecotoxicological tests to assess the environmental risk of soil contamination and its rehabilitation. Although the studied soil can be considered contaminated taking into account the total soil concentrations of Al, As, Cu and Pb, the low concentrations of the same chemical elements in extractable solutions, that simulated the fractions really available for organisms, did not demonstrate a substantial toxic effects in the organisms and, consequently, negative impact on the environment.

  8. Electric Eels Concentrate Their Electric Field to Induce Involuntary Fatigue in Struggling Prey.

    Science.gov (United States)

    Catania, Kenneth C

    2015-11-16

    Nature is replete with predator venoms that immobilize prey by targeting ion channels. Electric eels (Electrophorus electricus) take a different tactic to accomplish the same end. Striking eels emit electricity in volleys of 1 ms, high-voltage pulses. Each pulse is capable of activating prey motor neuron efferents, and hence muscles. In a typical attack, eel discharges cause brief, immobilizing tetanus, allowing eels to swallow small prey almost immediately. Here I show that when eels struggle with large prey or fish held precariously, they commonly curl to bring their own tail to the opposite side of prey, sandwiching it between the two poles of their powerful electric organ. They then deliver volleys of high-voltage pulses. Shortly thereafter, eels juggle prey into a favorable position for swallowing. Recordings from electrodes placed within prey items show that this curling behavior at least doubles the field strength within shocked prey, most likely ensuring reliable activation of the majority of prey motor neurons. Simulated pulse trains, or pulses from an eel-triggered stimulator, applied to a prey muscle preparations result in profound muscle fatigue and loss of contractile force. Consistent with this result, video recordings show that formerly struggling prey are temporarily immobile after this form of attack, allowing the manipulation of prey that might otherwise escape. These results reveal a unique use of electric organs to a unique end; eels superimpose electric fields from two poles, ensuring maximal remote activation of prey efferents that blocks subsequent prey movement by inducing involuntary muscle fatigue. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Plasticity in extended phenotypes: orb web architectural responses to variations in prey parameters.

    Science.gov (United States)

    Blamires, Sean J

    2010-09-15

    A spider orb web is an extended phenotype; it modifies and interacts with the environment, influencing spider physiology. Orb webs are plastic, responding to variations in prey parameters. Studies attempting to understand how nutrients influence spider orb-web plasticity have been hampered by the inability to decouple prey nutrients from other, highly correlated, prey factors and the intrinsic link between prey protein and prey energy concentration. I analyzed the nutrient concentrations of cockroaches, and adult and juvenile crickets to devise experiments that controlled prey protein concentration while varying prey size, ingested mass, energy concentration and feeding frequency of the orb web spider Argiope keyserlingi. I found that A. keyserlingi alters overall architecture according to feeding frequency. Decoration length was inversely related to ingested prey mass and/or energy density in one experiment but directly related to ingested prey mass in another. These contradictory results suggest that factors not examined in this study have a confounding influence on decoration plasticity. As decorations attract prey as well as predators decreasing decoration investment may, in some instances, be attributable to benefits no longer outweighing the risks. Web area was altered according to feeding frequency, and mesh size altered according to feeding frequency and prey length. The number of radii in orb webs was unaffected by prey parameters. A finite amount of silk can be invested in the orb web, so spiders trade-off smaller mesh size with larger web capture area, explaining why feeding frequency influenced both web area and mesh size. Mesh size is additionally responsive to prey size via sensory cues, with spiders constructing webs suitable for catching the most common or most profitable prey.

  10. Predator and prey space use: dragonflies and tadpoles in an interactive game.

    Science.gov (United States)

    Hammond, John I; Luttbeg, Barney; Sih, Andrew

    2007-06-01

    Predator and prey spatial distributions have important population and community level consequences. However, little is known either theoretically or empirically about behavioral mechanisms that underlie the spatial patterns that emerge when predators and prey freely interact. We examined the joint space use and behavioral rules governing movement of freely interacting groups of odonate (dragonfly) predators and two size classes of anuran (tadpole) prey in arenas containing two patches with different levels of the prey's resource. Predator and prey movement and space use was quantified both when they were apart and together. When apart from predators, large tadpoles strongly preferred the high resource patch. When apart from prey, dragonflies weakly preferred the high resource patch. When together, large prey shifted to a uniform distribution, while predators strongly preferred the high resource patch. These patterns qualitatively fit the predictions of several three trophic level, ideal free distribution models. In contrast, the space use of small prey and predators did not deviate from uniform. Three measures of joint space use (spatial correlations, overlap, and co-occurrence) concurred in suggesting that prey avoidance of predators was more important than predator attraction to prey in determining overall spatial patterns. To gain additional insight into behavioral mechanisms, we used a model selection approach to identify behavioral movement rules that can potentially explain the observed, emergent patterns of space use. Prey were more likely to leave patches with more predators and more conspecific competitors; resources had relatively weak effects on prey movements. In contrast, predators were more likely to leave patches with low resources (that they do not consume) and more competing predators; prey had relatively little effect on predator movements. These results highlight the importance of investigating freely interacting predators and prey, the potential

  11. Causes of variation in prey profitability and its consequences for the intake rate of the Oystercatcher Haematopus ostralegus

    NARCIS (Netherlands)

    Zwarts, L; Ens, B.J.; GossCustard, JD; Hulscher, JB; Durell, SEALD

    1996-01-01

    Prey species have different morphological and behavioural adaptations to escape their predators. In this paper we review how these prey defenses affect prey profitability and intake rate for one predator, the Oystercatcher. Four rules govern profitability. First, within each species large prey are

  12. Temperature and prey capture: opposite relationships in two predator taxa

    DEFF Research Database (Denmark)

    Kruse, Peter Dalgas; Toft, Søren; Sunderland, Keith

    2008-01-01

    on the predation rate of two carabid beetles (Pterostichus versicolor and Calathus fuscipes) and two spiders (Clubiona phragmitis and Pardosa prativaga) using fruit flies (Drosophila melanogaster) as prey. 3. All four predators and the fruit fly increased their locomotory activity at higher temperatures. Activity...... moulded by light conditions depending on whether the predator is diurnally or nocturnally active. It was hypothesised that flying Diptera are vulnerable to carabid beetles only at low temperatures and over the full temperature range for spiders because carabids, in contrast to spiders, are not built...... to catch swiftly moving prey. 2. The first experiment examined the spontaneous locomotor activity of the predators and of fruit flies at different temperatures (5, 10, 15, 20, 25, and 30 °C) and light conditions (light, dark). A second experiment examined the effect of temperature and light...

  13. Small prey species' behaviour and welfare: implications for veterinary professionals.

    Science.gov (United States)

    McBride, E Anne

    2017-08-01

    People have obligations to ensure the welfare of animals under their care. Offences under the UK Animal Welfare Act are acts, or failures of action, causing unnecessary suffering. Veterinary professionals need to be able to provide current, scientifically based prophylactic advice, and respect the limits of their expertise. The ethical concept of a life worth living and the Five Freedoms are core to welfare. Behaviour is a central component, both influencing and influenced by physical health. Owners frequently misunderstand the behaviour of small prey mammals and how to meet their needs. This review provides insight into the physical-social (external) and the cognitive-emotional (internal) environments of small prey mammals, contextualised within an evolutionary perspective. This is extrapolated to captivity and practical suggestions given for meeting behavioural freedoms and enhancing client understanding and enjoyment of their animals, thereby improving welfare. © 2017 British Small Animal Veterinary Association.

  14. How sailfish use their bills to capture schooling prey

    DEFF Research Database (Denmark)

    Domenici, P.; Wilson, A.D.M.; Kurvers, R.H.J.M.

    2014-01-01

    The istiophorid family of billfishes is characterized by an extended rostrum or ‘bill’. While various functions (e.g. foraging and hydrodynamic benefits) have been proposed for this structure, until now no study has directly investigated the mechanisms by which billfishes use their rostrum to feed...... on prey. Here, we present the first unequivocal evidence of how the bill is used by Atlantic sailfish (Istiophorus albicans) to attack schooling sardines in the open ocean. Using high-speed video-analysis, we show that (i) sailfish manage to insert their bill into sardine schools without eliciting...... an evasive response and (ii) subsequently use their bill to either tap on individual prey targets or to slash through the school with powerful lateral motions characterized by one of the highest accelerations ever recorded in an aquatic vertebrate. Our results demonstrate that the combination of stealth...

  15. Web-building spiders attract prey by storing decaying matter

    Science.gov (United States)

    Bjorkman-Chiswell, Bojun T.; Kulinski, Melissa M.; Muscat, Robert L.; Nguyen, Kim A.; Norton, Briony A.; Symonds, Matthew R. E.; Westhorpe, Gina E.; Elgar, Mark A.

    The orb-weaving spider Nephila edulis incorporates into its web a band of decaying animal and plant matter. While earlier studies demonstrate that larger spiders utilise these debris bands as caches of food, the presence of plant matter suggests additional functions. When organic and plastic items were placed in the webs of N. edulis, some of the former but none of the latter were incorporated into the debris band. Using an Y-maze olfactometer, we show that sheep blowflies Lucilia cuprina are attracted to recently collected debris bands, but that this attraction does not persist over time. These data reveal an entirely novel foraging strategy, in which a sit-and-wait predator attracts insect prey by utilising the odours of decaying organic material. The spider's habit of replenishing the debris band may be necessary to maintain its efficacy for attracting prey.

  16. Environmental versus demographic variability in stochastic predator-prey models

    Science.gov (United States)

    Dobramysl, U.; Täuber, U. C.

    2013-10-01

    In contrast to the neutral population cycles of the deterministic mean-field Lotka-Volterra rate equations, including spatial structure and stochastic noise in models for predator-prey interactions yields complex spatio-temporal structures associated with long-lived erratic population oscillations. Environmental variability in the form of quenched spatial randomness in the predation rates results in more localized activity patches. Our previous study showed that population fluctuations in rare favorable regions in turn cause a remarkable increase in the asymptotic densities of both predators and prey. Very intriguing features are found when variable interaction rates are affixed to individual particles rather than lattice sites. Stochastic dynamics with demographic variability in conjunction with inheritable predation efficiencies generate non-trivial time evolution for the predation rate distributions, yet with overall essentially neutral optimization.

  17. Status of pelagic prey fishes in Lake Michigan, 2013

    Science.gov (United States)

    Warner, David M.; Farha, Steven A.; O'Brien, Timothy P.; Ogilvie, Lynn; Claramunt, Randall M.; Hanson, Dale

    2014-01-01

    Acoustic surveys were conducted in late summer/early fall during the years 1992-1996 and 2001-2013 to estimate pelagic prey fish biomass in Lake Michigan. Midwater trawling during the surveys as well as target strength provided a measure of species and size composition of the fish community for use in scaling acoustic data and providing species-specific abundance estimates. The 2013 survey consisted of 27 acoustic transects (546 km total) and 31 midwater trawl tows. Mean prey fish biomass was 6.1 kg/ha (relative standard error, RSE = 11%) or 29.6 kilotonnes (kt = 1,000 metric tons), which was similar to the estimate in 2012 (31.1 kt) and 23.5% of the long-term (18 years) mean. The numeric density of the 2013 alewife year class was 6% of the time series average and this year-class contributed 4% of total alewife biomass (5.2 kg/ha, RSE = 12%). Alewife ≥age-1 comprised 96% of alewife biomass. In 2013, alewife comprised 86% of total prey fish biomass, while rainbow smelt and bloater were 4 and 10% of total biomass, respectively. Rainbow smelt biomass in 2013 (0.24 kg/ha, RSE = 17%) was essentially identical to the rainbow smelt biomass in 2012 and was 6% of the long term mean. Bloater biomass in 2013 was 0.6 kg/ha, only half the 2012 biomass, and 6% of the long term mean. Mean density of small bloater in 2013 (29 fish/ha, RSE = 29%) was lower than peak values observed in 2007-2009 and was 23% of the time series mean. In 2013, pelagic prey fish biomass in Lake Michigan was similar to Lake Huron, but pelagic community composition differs in the two lakes, with Lake Huron dominated by bloater.

  18. Isolation of Newcastle disease virus from birds of prey.

    Science.gov (United States)

    Chu, H P; Trow, E W; Greenwood, A G; Jennings, A R; Keymer, I F

    1976-01-01

    In the 4 year period 1971-74 11 isolations of Newcastle Disease Virus (NDV) were made from 44 birds of prey that died in captivity. Three species of Falconiformes were involved, including one red-headed falcon (Falco chicquera), 5 European kestrels (F. tinnunculus), and 2 secretary birds (Sagittarius serpentarius), also 2 species of Strigiformes, comprising 2 barn owls (Tyto alba) and one little owl (Athene noctua). All NDV isolates were of the velogenic type.

  19. A STAGE-STRUCTURED AND HARVESTING PREDATOR-PREY SYSTEM

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    A predator-prey system with independent harvesting in either species and BeddingtonDeAngelis functional response is investigated. By analyzing characteristic equations and using an iterative technique,we obtain a set of easily verifiable sufficient conditions,which ensure the local and global stability of the nonnegative equilibria of the system. It is also shown that the time delay can cause a stable equilibrium to become unstable and even a switching of stabilities. Numerical simulations are carried out t...

  20. Effects of seasonal growth on delayed prey-predator model

    Energy Technology Data Exchange (ETDEWEB)

    Gakkhar, Sunita [Department of Mathematics, IIT Roorkee, Roorkee 247667 (India)], E-mail: sungkfma@iitr.ernet.in; Sahani, Saroj Kumar [Department of Mathematics, IIT Roorkee, Roorkee 247667 (India)], E-mail: sarojdma@iitr.ernet.in; Negi, Kuldeep [Department of Mathematics, IIT Roorkee, Roorkee 247667 (India)], E-mail: negikdma@iitr.ernet.in

    2009-01-15

    The dynamic behavior of a delayed predator-prey system with Holling II functional response is investigated. The stability analysis has been carried out and existence of Hopf bifurcation has been established. The complex dynamic behavior due to time delay has been explored. The effects of seasonal growth on the complex dynamics have been simulated. The model shows a rich variety of behavior, including period doubling, quasi-periodicity, chaos, transient chaos, and windows of periodicity.