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Sample records for inhibition plant growth

  1. Comparison of toxicity to terrestrial plants with algal growth inhibition by herbicides

    SciTech Connect

    Garten, C.T. Jr.; Frank, M.L.

    1984-10-01

    The toxicities of 21 different herbicides to algae (Selenastrum capricornutum and Chlorella vulgaris) and to terrestrial plants (radishes, barley, and bush beans or soybeans) were compared to order to determine the feasibility of using a short-term (96-h) algal growth inhibition test for identifying chemicals having potential toxicity in a 4-week terrestrial plant bioassay. The toxicity of each test chemical, usually in combination with a commercial formulation, was evaluated at six nominal concentrations, between 0 and 100 mg/L growth medium in the algal bioassay or between 0 and 100 mg/kg substate in the terrestrial plant bioassay, in terms of both (1) the no-observed-effect concentration (NOEC), i.e., the highest concentration tested at which no significant (P < 0.05, one-sided test) reduction in algal growth rate or in terrestrial plant yield, relative to controls, was observed; and (2) the concentration at which algal growth rate or terrestrial plant yield was reduced by 50% or more relative to controls. There was generally poor agreement between results from the two types of bioassays; results from algal growth inhibition tests were not significantly correlated with results from the terrestrial plant bioassays. Overall, there was an approximately 50% chance of an algal bioassay, using Selenastrum capricornutum, successfully screening (detecting) herbicide levels that reduced terrestrial plant yield. The results indicated that algal growth inhibition tests cannot be used generically to predict phytotoxicity of herbicides to terrestrial plant species. 7 references, 14 tables.

  2. Thermal treatment and leaching of biochar alleviates plant growth inhibition from mobile organic compounds

    PubMed Central

    Sackett, Tara E.; Thomas, Sean C.

    2016-01-01

    Recent meta-analyses of plant responses to biochar boast positive average effects of between 10 and 40%. Plant responses, however, vary greatly across systems, and null or negative biochar effects are increasingly reported. The mechanisms responsible for such responses remain unclear. In a glasshouse experiment we tested the effects of three forestry residue wood biochars, applied at five dosages (0, 5, 10, 20, and 50 t/ha) to a temperate forest drystic cambisol as direct surface applications and as complete soil mixes on the herbaceous pioneers Lolium multiflorum and Trifolium repens. Null and negative effects of biochar on growth were found in most cases. One potential cause for null and negative plant responses to biochar is plant exposure to mobile compounds produced during pyrolysis that leach or evolve following additions of biochars to soil. In a second glasshouse experiment we examined the effects of simple leaching and heating techniques to ameliorate potentially phytotoxic effects of volatile and leachable compounds released from biochar. We used Solid Phase Microextraction (SPME)–gas chromatography–mass spectrometry (GC-MS) to qualitatively describe organic compounds in both biochar (through headspace extraction), and in the water leachates (through direct injection). Convection heating and water leaching of biochar prior to application alleviated growth inhibition. Additionally, growth was inhibited when filtrate from water-leached biochar was applied following germination. SPME-GC-MS detected primarily short-chained carboxylic acids and phenolics in both the leachates and solid chars, with relatively high concentrations of several known phytotoxic compounds including acetic acid, butyric acid, 2,4-di-tert-butylphenol and benzoic acid. We speculate that variable plant responses to phytotoxic organic compounds leached from biochars may largely explain negative plant growth responses and also account for strongly species-specific patterns of plant

  3. Thermal treatment and leaching of biochar alleviates plant growth inhibition from mobile organic compounds.

    PubMed

    Gale, Nigel V; Sackett, Tara E; Thomas, Sean C

    2016-01-01

    Recent meta-analyses of plant responses to biochar boast positive average effects of between 10 and 40%. Plant responses, however, vary greatly across systems, and null or negative biochar effects are increasingly reported. The mechanisms responsible for such responses remain unclear. In a glasshouse experiment we tested the effects of three forestry residue wood biochars, applied at five dosages (0, 5, 10, 20, and 50 t/ha) to a temperate forest drystic cambisol as direct surface applications and as complete soil mixes on the herbaceous pioneers Lolium multiflorum and Trifolium repens. Null and negative effects of biochar on growth were found in most cases. One potential cause for null and negative plant responses to biochar is plant exposure to mobile compounds produced during pyrolysis that leach or evolve following additions of biochars to soil. In a second glasshouse experiment we examined the effects of simple leaching and heating techniques to ameliorate potentially phytotoxic effects of volatile and leachable compounds released from biochar. We used Solid Phase Microextraction (SPME)-gas chromatography-mass spectrometry (GC-MS) to qualitatively describe organic compounds in both biochar (through headspace extraction), and in the water leachates (through direct injection). Convection heating and water leaching of biochar prior to application alleviated growth inhibition. Additionally, growth was inhibited when filtrate from water-leached biochar was applied following germination. SPME-GC-MS detected primarily short-chained carboxylic acids and phenolics in both the leachates and solid chars, with relatively high concentrations of several known phytotoxic compounds including acetic acid, butyric acid, 2,4-di-tert-butylphenol and benzoic acid. We speculate that variable plant responses to phytotoxic organic compounds leached from biochars may largely explain negative plant growth responses and also account for strongly species-specific patterns of plant

  4. Thermal treatment and leaching of biochar alleviates plant growth inhibition from mobile organic compounds

    PubMed Central

    Sackett, Tara E.; Thomas, Sean C.

    2016-01-01

    Recent meta-analyses of plant responses to biochar boast positive average effects of between 10 and 40%. Plant responses, however, vary greatly across systems, and null or negative biochar effects are increasingly reported. The mechanisms responsible for such responses remain unclear. In a glasshouse experiment we tested the effects of three forestry residue wood biochars, applied at five dosages (0, 5, 10, 20, and 50 t/ha) to a temperate forest drystic cambisol as direct surface applications and as complete soil mixes on the herbaceous pioneers Lolium multiflorum and Trifolium repens. Null and negative effects of biochar on growth were found in most cases. One potential cause for null and negative plant responses to biochar is plant exposure to mobile compounds produced during pyrolysis that leach or evolve following additions of biochars to soil. In a second glasshouse experiment we examined the effects of simple leaching and heating techniques to ameliorate potentially phytotoxic effects of volatile and leachable compounds released from biochar. We used Solid Phase Microextraction (SPME)–gas chromatography–mass spectrometry (GC-MS) to qualitatively describe organic compounds in both biochar (through headspace extraction), and in the water leachates (through direct injection). Convection heating and water leaching of biochar prior to application alleviated growth inhibition. Additionally, growth was inhibited when filtrate from water-leached biochar was applied following germination. SPME-GC-MS detected primarily short-chained carboxylic acids and phenolics in both the leachates and solid chars, with relatively high concentrations of several known phytotoxic compounds including acetic acid, butyric acid, 2,4-di-tert-butylphenol and benzoic acid. We speculate that variable plant responses to phytotoxic organic compounds leached from biochars may largely explain negative plant growth responses and also account for strongly species-specific patterns of plant

  5. Thermal treatment and leaching of biochar alleviates plant growth inhibition from mobile organic compounds.

    PubMed

    Gale, Nigel V; Sackett, Tara E; Thomas, Sean C

    2016-01-01

    Recent meta-analyses of plant responses to biochar boast positive average effects of between 10 and 40%. Plant responses, however, vary greatly across systems, and null or negative biochar effects are increasingly reported. The mechanisms responsible for such responses remain unclear. In a glasshouse experiment we tested the effects of three forestry residue wood biochars, applied at five dosages (0, 5, 10, 20, and 50 t/ha) to a temperate forest drystic cambisol as direct surface applications and as complete soil mixes on the herbaceous pioneers Lolium multiflorum and Trifolium repens. Null and negative effects of biochar on growth were found in most cases. One potential cause for null and negative plant responses to biochar is plant exposure to mobile compounds produced during pyrolysis that leach or evolve following additions of biochars to soil. In a second glasshouse experiment we examined the effects of simple leaching and heating techniques to ameliorate potentially phytotoxic effects of volatile and leachable compounds released from biochar. We used Solid Phase Microextraction (SPME)-gas chromatography-mass spectrometry (GC-MS) to qualitatively describe organic compounds in both biochar (through headspace extraction), and in the water leachates (through direct injection). Convection heating and water leaching of biochar prior to application alleviated growth inhibition. Additionally, growth was inhibited when filtrate from water-leached biochar was applied following germination. SPME-GC-MS detected primarily short-chained carboxylic acids and phenolics in both the leachates and solid chars, with relatively high concentrations of several known phytotoxic compounds including acetic acid, butyric acid, 2,4-di-tert-butylphenol and benzoic acid. We speculate that variable plant responses to phytotoxic organic compounds leached from biochars may largely explain negative plant growth responses and also account for strongly species-specific patterns of plant

  6. Volatiles of bacterial antagonists inhibit mycelial growth of the plant pathogen Rhizoctonia solani.

    PubMed

    Kai, Marco; Effmert, Uta; Berg, Gabriele; Piechulla, Birgit

    2007-05-01

    Bacterial antagonists are bacteria that negatively affect the growth of other organisms. Many antagonists inhibit the growth of fungi by various mechanisms, e.g., secretion of lytic enzymes, siderophores and antibiotics. Such inhibition of fungal growth may indirectly support plant growth. Here, we demonstrate that small organic volatile compounds (VOCs) emitted from bacterial antagonists negatively influence the mycelial growth of the soil-borne phytopathogenic fungus Rhizoctonia solani Kühn. Strong inhibitions (99-80%) under the test conditions were observed with Stenotrophomonas maltophilia R3089, Serratia plymuthica HRO-C48, Stenotrophomonas rhizophila P69, Serratia odorifera 4Rx13, Pseudomonas trivialis 3Re2-7, S. plymuthica 3Re4-18 and Bacillus subtilis B2g. Pseudomonas fluorescens L13-6-12 and Burkholderia cepacia 1S18 achieved 30% growth reduction. The VOC profiles of these antagonists, obtained through headspace collection and analysis on GC-MS, show different compositions and complexities ranging from 1 to almost 30 compounds. Most volatiles are species-specific, but overlapping volatile patterns were found for Serratia spp. and Pseudomonas spp. Many of the bacterial VOCs could not be identified for lack of match with mass-spectra of volatiles in the databases. PMID:17180381

  7. Plant-Made Trastuzumab (Herceptin) Inhibits HER2/Neu+ Cell Proliferation and Retards Tumor Growth

    PubMed Central

    Komarova, Tatiana V.; Kosorukov, Vyacheslav S.; Frolova, Olga Y.; Petrunia, Igor V.; Skrypnik, Ksenia A.; Gleba, Yuri Y.; Dorokhov, Yuri L.

    2011-01-01

    Background Plant biotechnology provides a valuable contribution to global health, in part because it can decrease the cost of pharmaceutical products. Breast cancer can now be successfully treated by a humanized monoclonal antibody (mAb), trastuzumab (Herceptin). A course of treatment, however, is expensive and requires repeated administrations of the mAb. Here we used an Agrobacterium-mediated transient expression system to produce trastuzumab in plant cells. Methodology/Principal Findings We describe the cloning and expression of gene constructs in Nicotiana benthamiana plants using intron-optimized Tobacco mosaic virus- and Potato virus X-based vectors encoding, respectively, the heavy and light chains of trastuzumab. Full-size antibodies extracted and purified from plant tissues were tested for functionality and specificity by (i) binding to HER2/neu on the surface of a human mammary gland adenocarcinoma cell line, SK-BR-3, in fluorescence-activated cell sorting assay and (ii) testing the in vitro and in vivo inhibition of HER-2-expressing cancer cell proliferation. We show that plant-made trastuzumab (PMT) bound to the Her2/neu oncoprotein of SK-BR-3 cells and efficiently inhibited SK-BR-3 cell proliferation. Furthermore, mouse intraperitoneal PMT administration retarded the growth of xenografted tumors derived from human ovarian cancer SKOV3 Her2+ cells. Conclusions/Significance We conclude that PMT is active in suppression of cell proliferation and tumor growth. PMID:21390232

  8. Cross-kingdom inhibition of breast cancer growth by plant miR159.

    PubMed

    Chin, Andrew R; Fong, Miranda Y; Somlo, George; Wu, Jun; Swiderski, Piotr; Wu, Xiwei; Wang, Shizhen Emily

    2016-02-01

    MicroRNAs (miRNAs) are critical regulators of gene expression, and exert extensive impacts on development, physiology, and disease of eukaryotes. A high degree of parallelism is found in the molecular basis of miRNA biogenesis and action in plants and animals. Recent studies interestingly suggest a potential cross-kingdom action of plant-derived miRNAs, through dietary intake, in regulating mammalian gene expression. Although the source and scope of plant miRNAs detected in mammalian specimens remain controversial, these initial studies inspired us to determine whether plant miRNAs can be detected in Western human sera and whether these plant miRNAs are able to influence gene expression and cellular processes related to human diseases such as cancer. Here we found that Western donor sera contained the plant miRNA miR159, whose abundance in the serum was inversely correlated with breast cancer incidence and progression in patients. In human sera, miR159 was predominantly detected in the extracellular vesicles, and was resistant to sodium periodate oxidation suggesting the plant-originated 2'-O-methylation on the 3' terminal ribose. In breast cancer cells but not non-cancerous mammary epithelial cells, a synthetic mimic of miR159 was capable of inhibiting proliferation by targeting TCF7 that encodes a Wnt signaling transcription factor, leading to a decrease in MYC protein levels. Oral administration of miR159 mimic significantly suppressed the growth of xenograft breast tumors in mice. These results demonstrate for the first time that a plant miRNA can inhibit cancer growth in mammals. PMID:26794868

  9. Inhibition of polyamine biosynthesis and growth in plant pathogenic fungi in vitro.

    PubMed

    Rajam, B; Rajam, M V

    1996-02-01

    Polyamine (PA) biosynthesis inhibitors, difluoromethylornithine (DFMO), difluoromethylarginine (DFMA), methylglyoxal bis-(guanylhydrazone) (MGBG) and bis-(cyclohexylammonium) sulphate (BCHA) have been tested for their effects on colony diameters at different intervals after inoculation of four plant pathogenic fungi (Helminthosporium oryzae, Curvularia lunata, Pythium aphanidermatum and Colletotrichum capsici). All these inhibitors, except DFMA had strongly retarded the growth of four fungi in a dose- and species-dependent fashion, and H. oryzae and C. lunata were found to be most sensitive to the effects of PA inhibitors. P. aphanidermatum and C. capsici were relatively insensitive and required rather high concentrations of inhibitors to get greater inhibition of mycelial growth, except DFMA which had stimulatory effect on the growth of these two fungi. However DFMA had greatly suppressed the growth of H. oryzae and C. lunata. The effect was generally more pronounced with MGBG than with DFMO and BCHA, and 1 mM Put completely prevented the inhibitory effects of 1 and 5 mM DFMO. Analysis of free and conjugated PAs in two sensitive fungi (H. oryzae and C. lunata) revealed that Put was present in highest concentrations followed by Spd and Spm and their levels were greatly reduced by DFMO application, and such inhibitions were totally reversed by exogenously supplied Put; in fact, PA titers were considerably increased by 1 mM Put alone and in combination with 1 mM DFMO. These results suggest that PA inhibitors, particularly DFMO and MGBG may be useful as target-specific fungicides in plants.

  10. Plant growth inhibition by cis-cinnamoyl glucosides and cis-cinnamic acid.

    PubMed

    Hiradate, Syuntaro; Morita, Sayaka; Furubayashi, Akihiro; Fujii, Yoshiharu; Harada, Jiro

    2005-03-01

    Spiraea thunbergii Sieb. contains 1-O-cis-cinnamoyl-beta-D-glucopyranose (CG) and 6-O-(4'-hydroxy-2'-methylene-butyroyl)-1-O-cis-cinnamoyl-beta-D-glucopyranose (BCG) as major plant growth inhibiting constituents. In the present study, we determined the inhibitory activity of CG and BCG on root elongation of germinated seedlings of lettuce (Lactuca sativa), pigweed (Amaranthus retroflexus), red clover (Trifolium pratense), timothy (Phleum pratense), and bok choy (Brassica rapa var chinensis) in comparison with that of two well-known growth inhibitors, 2,4-dichlorophenoxyacetic acid (2,4-D) and (+)-2-cis-4-trans-abscisic acid (cis-ABA), as well as two related chemicals of CG and BCG, cis-cinnamic acid (cis-CA) and trans-cinnamic acid (trans-CA). The EC50 values for CG and BCG on lettuce were roughly one-half to one-quarter of the value for cis-ABA. cis-Cinnamic acid, which is a component of CG and BCG, possessed almost the same inhibitory activity of CG and BCG, suggesting that the essential chemical structure responsible for the inhibitory activity of CG and BCG is cis-CA. The cis-stereochemistry of the methylene moiety is apparently needed for high inhibitory activity, as trans-CA had an EC50 value roughly 100 times that of CG, BCG, and cis-CA. Growth inhibition by CG, BCG, and cis-CA was influenced by the nature of the soil in the growing medium: alluvial soil preserved the bioactivity, whereas volcanic ash and calcareous soils inhibited bioactivity. These findings indicate a potential role of cis-CA and its glucosides as allelochemicals for use as plant growth regulators in agricultural fields.

  11. Plant growth inhibition by cis-cinnamoyl glucosides and cis-cinnamic acid.

    PubMed

    Hiradate, Syuntaro; Morita, Sayaka; Furubayashi, Akihiro; Fujii, Yoshiharu; Harada, Jiro

    2005-03-01

    Spiraea thunbergii Sieb. contains 1-O-cis-cinnamoyl-beta-D-glucopyranose (CG) and 6-O-(4'-hydroxy-2'-methylene-butyroyl)-1-O-cis-cinnamoyl-beta-D-glucopyranose (BCG) as major plant growth inhibiting constituents. In the present study, we determined the inhibitory activity of CG and BCG on root elongation of germinated seedlings of lettuce (Lactuca sativa), pigweed (Amaranthus retroflexus), red clover (Trifolium pratense), timothy (Phleum pratense), and bok choy (Brassica rapa var chinensis) in comparison with that of two well-known growth inhibitors, 2,4-dichlorophenoxyacetic acid (2,4-D) and (+)-2-cis-4-trans-abscisic acid (cis-ABA), as well as two related chemicals of CG and BCG, cis-cinnamic acid (cis-CA) and trans-cinnamic acid (trans-CA). The EC50 values for CG and BCG on lettuce were roughly one-half to one-quarter of the value for cis-ABA. cis-Cinnamic acid, which is a component of CG and BCG, possessed almost the same inhibitory activity of CG and BCG, suggesting that the essential chemical structure responsible for the inhibitory activity of CG and BCG is cis-CA. The cis-stereochemistry of the methylene moiety is apparently needed for high inhibitory activity, as trans-CA had an EC50 value roughly 100 times that of CG, BCG, and cis-CA. Growth inhibition by CG, BCG, and cis-CA was influenced by the nature of the soil in the growing medium: alluvial soil preserved the bioactivity, whereas volcanic ash and calcareous soils inhibited bioactivity. These findings indicate a potential role of cis-CA and its glucosides as allelochemicals for use as plant growth regulators in agricultural fields. PMID:15898503

  12. Effect of Trichoderma on plant growth: A balance between inhibition and growth promotion.

    PubMed

    Ousley, M A; Lynch, J M; Whipps, J M

    1993-11-01

    The effect of lettuce (Latuca sativa L.) germination and growth in nonsterilized potting compost of 0.1% and 1.0% w/w incorporation of fermenter biomass inocula of six strains of Trichoderma was investigated. Except for strains WT and T35 at 0.1 % w/w, all inocula inhibited germination. Biomass of strains WT, T35, 20, and 47 at 1.0% promoted shoot fresh weight, whereas strains TH1 and 8MF2 were inhibitory. In contrast, when biomass of strains WT, TH1, and 8MF2 was autoclaved and incorporated at 1%, shoot fresh weight was promoted, but the biomass of T35 was inhibitory. None of the strains incorporated at 0.1 % w/w increased shoot fresh weight, and autoclaved biomass of TH1, T35, and 20 incorporated at 0.1% w/w resulted in lower shoot fresh weights in comparison with uninoculated controls. The shoot dry weight of lettuce seedlings could be enhanced by germinating seeds in uninoculated compost and after five days' growth transferring them into WT-inoculated compost. Inoculum of strain TH1 when applied using this method was very inhibitory. With WT the degree of increase in shoot fresh weight and germination rate declined as the fermentation time to produce inocula was increased.

  13. Effect of Trichoderma on plant growth: A balance between inhibition and growth promotion.

    PubMed

    Ousley, M A; Lynch, J M; Whipps, J M

    1993-11-01

    The effect of lettuce (Latuca sativa L.) germination and growth in nonsterilized potting compost of 0.1% and 1.0% w/w incorporation of fermenter biomass inocula of six strains of Trichoderma was investigated. Except for strains WT and T35 at 0.1 % w/w, all inocula inhibited germination. Biomass of strains WT, T35, 20, and 47 at 1.0% promoted shoot fresh weight, whereas strains TH1 and 8MF2 were inhibitory. In contrast, when biomass of strains WT, TH1, and 8MF2 was autoclaved and incorporated at 1%, shoot fresh weight was promoted, but the biomass of T35 was inhibitory. None of the strains incorporated at 0.1 % w/w increased shoot fresh weight, and autoclaved biomass of TH1, T35, and 20 incorporated at 0.1% w/w resulted in lower shoot fresh weights in comparison with uninoculated controls. The shoot dry weight of lettuce seedlings could be enhanced by germinating seeds in uninoculated compost and after five days' growth transferring them into WT-inoculated compost. Inoculum of strain TH1 when applied using this method was very inhibitory. With WT the degree of increase in shoot fresh weight and germination rate declined as the fermentation time to produce inocula was increased. PMID:24190096

  14. Inhibition of Abscisic Acid Biosynthesis in Cercospora rosicola by Inhibitors of Gibberellin Biosynthesis and Plant Growth Retardants

    PubMed Central

    Norman, Shirley M.; Poling, Stephen M.; Maier, Vincent P.; Orme, Edward D.

    1983-01-01

    The fungus Cercospora rosicola produces abscisic acid (ABA) as a secondary metabolite. We developed a convenient system using this fungus to determine the effects of compounds on the biosynthesis of ABA. Inasmuch as ABA and the gibberellins (GAs) both arise via the isoprenoid pathway, it was of interest to determine if inhibitors of GA biosynthesis affect ABA biosynthesis. All five putative inhibitors of GA biosynthesis tested inhibited ABA biosynthesis. Several plant growth retardants with poorly understood actions in plants were also tested; of these, six inhibited ABA biosynthesis to varying degrees and two had no effect. Effects of plant growth retardants on various branches of the isoprenoid biosynthetic pathway may help to explain some of the diverse and unexpected results reported for these compounds. Knowledge that certain inhibitors of GA biosynthesis also have the ability to inhibit ABA biosynthesis in C. rosicola indicates the need for further studies in plants on the mode of action of these compounds. PMID:16662775

  15. Cyperus rotundus extract inhibits acetylcholinesterase activity from animal and plants as well as inhibits germination and seedling growth in wheat and tomato.

    PubMed

    Sharma, Rashmi; Gupta, Rajendra

    2007-05-30

    Cyperus rotundus (nutgrass) is the world's worst invasive weed through tubers. Its success in dominating natural habitats depends on its ability to prevent herbivory, and to kill or suppress other plants growing in its vicinity. The present study was done to investigate whether chemicals in nutgrass target neuronal and non-neuronal acetylcholinesterases to affect surrounding animals and plants respectively. Methanolic extract of tubers of nutgrass strongly inhibited activity of AChE from electric eel, wheat and tomato. It also inhibited seed germination and seedling growth in wheat and tomato. Our results suggest that inhibitor of AChE in nutgrass possibly acts as agent of plant's war against (a) herbivore animals, and (b) other plants trying to grow in the same habitat. An antiAChE from nutgrass has been purified by employing chromatography and crystallization. The structural determination of the purified inhibitor is in progress.

  16. Specificity of 1-triacontanol as a plant growth stimulator and inhibition of its effect by other long-chain compounds.

    PubMed

    Jones, J; Wert, V; Ries, S

    1979-01-01

    The effect of several analogs of 1-triacontanol (TRIA), differing in C-chain length (16-32), the position of the hydroxyl group and the terminal functional group, were tested alone and in combination with TRIA on the growth of rice (Oryza sativa L.), maize (Zea mays L.) and tomato (Lycopersicon esculentum Mill.) seedlings. Applied alone, none of the compounds caused an increase in growth; thus, chain length (30 C) and presence and position (terminal) of the hydroxyl group appear to be specific for the growth-promoting activity of TRIA. When applied simultaneously with TRIA, all analogs inhibited the response to the latter in all three test plants, whether applied in the nutrient solution, as foliar spray or by seed soaking. 1-Octacosanol inhibited the response of rice seedlings to 2.3 x 10(-8) M TRIA at concentrations as low as 2.4 x 10(-12) M. Thus preparations of TRIA and application equipment must be free from trace amounts of other long-chain compounds if they are to be used to increase plant growth.

  17. CsPAO4 of Citrus sinensis functions in polyamine terminal catabolism and inhibits plant growth under salt stress

    PubMed Central

    Wang, Wei; Liu, Ji-Hong

    2016-01-01

    Polyamine oxidase (PAO) is a key enzyme catalyzing polyamine catabolism leading to H2O2 production. We previously demonstrated that Citrus sinensis contains six putative PAO genes, but their functions are not well understood. In this work, we reported functional elucidation of CsPAO4 in polyamine catabolism and salt stress response. CsPAO4 was localized to the apoplast and used both spermidine (Spd) and spermine (Spm) as substrates for terminal catabolism. Transgenic plants overexpressing CsPAO4 displayed prominent increase in PAO activity, concurrent with marked decrease of Spm and Spd and elevation of H2O2. Seeds of transgenic lines displayed better germination when compared with wild type (WT) under salt stress. However, both vegetative growth and root elongation of the transgenic lines were prominently inhibited under salt stress, accompanied by higher level of H2O2 and more conspicuous programmed cell death (PCD). Exogenous supply of catalase (CAT), a H2O2 scavenger, partially recovered the vegetative growth and root elongation. In addition, spermine inhibited root growth of transgenic plants. Taken together, these data demonstrated that CsPAO4 accounts for production of H2O2 causing oxidative damages under salt stress and that down-regulation of a PAO gene involved in polyamine terminal catabolism may be an alternative approach for improving salt stress tolerance. PMID:27535697

  18. CsPAO4 of Citrus sinensis functions in polyamine terminal catabolism and inhibits plant growth under salt stress.

    PubMed

    Wang, Wei; Liu, Ji-Hong

    2016-01-01

    Polyamine oxidase (PAO) is a key enzyme catalyzing polyamine catabolism leading to H2O2 production. We previously demonstrated that Citrus sinensis contains six putative PAO genes, but their functions are not well understood. In this work, we reported functional elucidation of CsPAO4 in polyamine catabolism and salt stress response. CsPAO4 was localized to the apoplast and used both spermidine (Spd) and spermine (Spm) as substrates for terminal catabolism. Transgenic plants overexpressing CsPAO4 displayed prominent increase in PAO activity, concurrent with marked decrease of Spm and Spd and elevation of H2O2. Seeds of transgenic lines displayed better germination when compared with wild type (WT) under salt stress. However, both vegetative growth and root elongation of the transgenic lines were prominently inhibited under salt stress, accompanied by higher level of H2O2 and more conspicuous programmed cell death (PCD). Exogenous supply of catalase (CAT), a H2O2 scavenger, partially recovered the vegetative growth and root elongation. In addition, spermine inhibited root growth of transgenic plants. Taken together, these data demonstrated that CsPAO4 accounts for production of H2O2 causing oxidative damages under salt stress and that down-regulation of a PAO gene involved in polyamine terminal catabolism may be an alternative approach for improving salt stress tolerance.

  19. CsPAO4 of Citrus sinensis functions in polyamine terminal catabolism and inhibits plant growth under salt stress.

    PubMed

    Wang, Wei; Liu, Ji-Hong

    2016-01-01

    Polyamine oxidase (PAO) is a key enzyme catalyzing polyamine catabolism leading to H2O2 production. We previously demonstrated that Citrus sinensis contains six putative PAO genes, but their functions are not well understood. In this work, we reported functional elucidation of CsPAO4 in polyamine catabolism and salt stress response. CsPAO4 was localized to the apoplast and used both spermidine (Spd) and spermine (Spm) as substrates for terminal catabolism. Transgenic plants overexpressing CsPAO4 displayed prominent increase in PAO activity, concurrent with marked decrease of Spm and Spd and elevation of H2O2. Seeds of transgenic lines displayed better germination when compared with wild type (WT) under salt stress. However, both vegetative growth and root elongation of the transgenic lines were prominently inhibited under salt stress, accompanied by higher level of H2O2 and more conspicuous programmed cell death (PCD). Exogenous supply of catalase (CAT), a H2O2 scavenger, partially recovered the vegetative growth and root elongation. In addition, spermine inhibited root growth of transgenic plants. Taken together, these data demonstrated that CsPAO4 accounts for production of H2O2 causing oxidative damages under salt stress and that down-regulation of a PAO gene involved in polyamine terminal catabolism may be an alternative approach for improving salt stress tolerance. PMID:27535697

  20. Potassium uptake supporting plant growth in the absence of AKT1 channel activity: Inhibition by ammonium and stimulation by sodium

    NASA Technical Reports Server (NTRS)

    Spalding, E. P.; Hirsch, R. E.; Lewis, D. R.; Qi, Z.; Sussman, M. R.; Lewis, B. D.

    1999-01-01

    A transferred-DNA insertion mutant of Arabidopsis that lacks AKT1 inward-rectifying K+ channel activity in root cells was obtained previously by a reverse-genetic strategy, enabling a dissection of the K+-uptake apparatus of the root into AKT1 and non-AKT1 components. Membrane potential measurements in root cells demonstrated that the AKT1 component of the wild-type K+ permeability was between 55 and 63% when external [K+] was between 10 and 1,000 microM, and NH4+ was absent. NH4+ specifically inhibited the non-AKT1 component, apparently by competing for K+ binding sites on the transporter(s). This inhibition by NH4+ had significant consequences for akt1 plants: K+ permeability, 86Rb+ fluxes into roots, seed germination, and seedling growth rate of the mutant were each similarly inhibited by NH4+. Wild-type plants were much more resistant to NH4+. Thus, AKT1 channels conduct the K+ influx necessary for the growth of Arabidopsis embryos and seedlings in conditions that block the non-AKT1 mechanism. In contrast to the effects of NH4+, Na+ and H+ significantly stimulated the non-AKT1 portion of the K+ permeability. Stimulation of akt1 growth rate by Na+, a predicted consequence of the previous result, was observed when external [K+] was 10 microM. Collectively, these results indicate that the AKT1 channel is an important component of the K+ uptake apparatus supporting growth, even in the "high-affinity" range of K+ concentrations. In the absence of AKT1 channel activity, an NH4+-sensitive, Na+/H+-stimulated mechanism can suffice.

  1. Isolation and Identification of Antifungal Compounds from Bacillus subtilis C9 Inhibiting the Growth of Plant Pathogenic Fungi

    PubMed Central

    Islam, Md. Rezuanul; Jeong, Yong Tae; Lee, Yong Se

    2012-01-01

    Antagonistic microorganisms against Rhizoctonia solani were isolated and their antifungal activities were investigated. Two hundred sixteen bacterial isolates were isolated from various soil samples and 19 isolates were found to antagonize the selected plant pathogenic fungi with varying degrees. Among them, isolate C9 was selected as an antagonistic microorganism with potential for use in further studies. Treatment with the selected isolate C9 resulted in significantly reduced incidence of stem-segment colonization by R. solani AG2-2(IV) in Zoysia grass and enhanced growth of grass. Through its biochemical, physiological, and 16S rDNA characteristics, the selected bacterium was identified as Bacillus subtilis subsp. subtilis. Mannitol (1%) and soytone (1%) were found to be the best carbon and nitrogen sources, respectively, for use in antibiotic production. An antibiotic compound, designated as DG4, was separated and purified from ethyl acetate extract of the culture broth of isolate C9. On the basis of spectral data, including proton nuclear magneric resonance (1H NMR), carbon nuclear magneric resonance (13C NMR), and mass analyses, its chemical structure was established as a stereoisomer of acetylbutanediol. Application of the ethyl acetate extract of isolate C9 to several plant pathogens resulted in dose-dependent inhibition. Treatment with the purified compound (an isomer of acetylbuanediol) resulted in significantly inhibited growth of tested pathogens. The cell free culture supernatant of isolate C9 showed a chitinase effect on chitin medium. Results from the present study demonstrated the significant potential of the purified compound from isolate C9 for use as a biocontrol agent as well as a plant growth promoter with the ability to trigger induced systemic resistance of plants. PMID:22783136

  2. Combined effects of plant extracts in inhibiting the growth of Bacillus cereus in reconstituted infant rice cereal.

    PubMed

    Jun, Hyejung; Kim, Jinsol; Bang, Jihyun; Kim, Hoikyung; Beuchat, Larry R; Ryu, Jee-Hoon

    2013-01-01

    A study was done to determine the potential use of plant extracts to inhibit the growth of Bacillus cereus in reconstituted infant rice cereal. A total of 2116 extracts were screened for inhibitory activity against B. cereus using an agar well diffusion assay. The minimal inhibitory concentrations (MIC) and minimal lethal concentrations (MLC) of 14 promising extracts in tryptic soy broth (TSB) were determined. Dryopteris erythrosora (autumn fern) root extract showed the lowest MIC (0.0156 mg/ml), followed by Siegesbeckia glabrescens (Siegesbeckia herb) leaf (0.0313 mg/ml), Morus alba (white mulberry) cortex (0.0313 mg/ml), Carex pumila (sand sedge) root (0.0625 mg/ml), and Citrus paradisi (grapefruit) seed (0.0625 mg/ml) extracts. The order of MLCs of extracts was D. erythrosora root (0.0156 mg/ml)inhibition, with a fractional inhibitory concentration index (FICI) of 0.75. Single and combined inhibitory activities of selected plant extracts against B. cereus in reconstituted infant rice cereal were investigated. The MICs of S. glabrescens, M. alba, D. erythrosora, and C. pumila extracts against B. cereus were 1.0, 2.0, 2.0, and 8.0mg/ml, respectively. A combination of D. erythrosora (1.00 mg/ml) and C. pumila (1.00 mg/ml) extracts showed a partial synergistic effect (FICI 0.63) in inhibiting the growth of B. cereus. Results indicate that by combining extracts, the amounts of D. erythrosora and C. pumila extracts can be reduced by 50% and 87.5%, respectively, compared with individual extracts, and give similar inhibitory activity in reconstituted infant rice cereal. Sensory evaluation showed that supplementing reconstituted

  3. Essential oil of Artemisia scoparia inhibits plant growth by generating reactive oxygen species and causing oxidative damage.

    PubMed

    Singh, Harminder Pal; Kaur, Shalinder; Mittal, Sunil; Batish, Daizy Rani; Kohli, Ravinder Kumar

    2009-02-01

    We investigated the chemical composition and phytotoxicity of the essential oil extracted from leaves of Artemisia scoparia Waldst. et Kit. (red stem wormwood, Asteraceae). GC/GC-MS analyses revealed 33 chemical constituents representing 99.83% of the oil. The oil, in general, was rich in monoterpenes that constitute 71.6%, with beta-myrcene (29.27%) as the major constituent followed by (+)-limonene (13.3%), (Z)-beta-ocimene (13.37%), and gamma-terpinene (9.51%). The oil and beta-myrcene were evaluated in a dose-response bioassay under laboratory conditions for phytotoxicity against three weeds-Avena fatua, Cyperus rotundus, and Phalaris minor. A significant reduction in germination, seedling growth, and dry matter accumulation was observed in the test weeds. At the lowest treatment of 0.07 mg/ml Artemisia oil, germination was reduced by 39%, 19%, and 10.6% in C. rotundus, P. minor, and A. fatua, respectively. However, the inhibitory effect of beta-myrcene was less. In general, a dose-dependent effect was observed and the growth declined with increasing concentration. Among the three weeds, the inhibitory effect was greatest on C. rotundus, so it was selected for further studies. We explored the explanation for observed growth inhibition in terms of reactive oxygen species (ROS: lipid peroxidation, membrane integrity, and amounts of conjugated dienes and hydrogen peroxide)-induced oxidative stress. Exposure of C. rotundus to Artemisia oil or beta-myrcene enhanced solute leakage, indicating membrane disintegration. There were increased levels of malondialdehyde and hydrogen peroxide, indicating lipid peroxidation and induction of oxidative stress. We conclude that Artemisia oil inhibits plant root growth through generation of ROS-induced oxidative damage.

  4. [Production of inhibiting plant growth and development hormones by pathogenic for legumes Pseudomonas genus bacteria].

    PubMed

    Dankevich, L A

    2013-01-01

    It has been studied the ability of pathogenic for legumes pathovars of Pseudomonas genus to produce ethylene and abscisic acid in vitro. A direct correlation between the level of ethylene production by agent of bacterial pea burn--Pseudomonas syringae pv. pisi and level of its aggressiveness for plants has been found. It is shown that the amount of abscisic acid synthesized by pathogenic for legumes Pseudomonas genus bacteria correlates with their aggressiveness for plants.

  5. Plant Growth Regulators.

    ERIC Educational Resources Information Center

    Nickell, Louis G.

    1978-01-01

    Describes the effect of "plant growth regulators" on plants, such as controlling the flowering, fruit development, plant size, and increasing crop yields. Provides a list of plant growth regulators which includes their chemical, common, and trade names, as well as their different use(s). (GA)

  6. Pharmacological activity in growth inhibition and apoptosis of cultured human leiomyomal cells of tropical plant Scutellaria barbata D. Don (Lamiaceae).

    PubMed

    Lee, Tae-Kyun; Lee, Yun-Jeong; Kim, Dong-Il; Kim, Hyung-Min; Chang, Young-Chae; Kim, Cheorl-Ho

    2006-01-01

    Scutellaria barbata D. Don (Lamiaceae) (SB), which is known in traditional Korean medicine, has been used as an anti-inflammatory and antitumor agent. Since uterine leiomyoma is the most common benign smooth muscle cell tumor of the myometrium, we aimed to determine the growth inhibition and the induction of apoptotic cell death brought about by the herb SB in two different leiomyomal cells, named LM-1 and LM-2, and to clarify the mechanism of this apoptosis. Water-soluble ingredients of SB, and the leiomyomal cell lines of LM-1 and LM-2, were used in vitro. Growth inhibition, induction of cell death, morphological features, the presence of DNA ladders, increases in Caspase 3-like activity, the effects of a Caspase 3 inhibitor on apoptotic cell death, and the release of Cytochrome C by SB were analyzed. SB inhibited the growth and decreased the viability of the leiomyomal cells. The viability of normal myomatrial smooth muscle cells (SMC) in the presence of low concentrations of SB was higher than those of leiomyomal cells. Apoptotic bodies and DNA ladders were observed to be induced in leiomyomal cells of LM-1 and LM-2 by SB. The synthetic tetrapeptide Caspase 3 inhibitor, N-acetyl-Asp-Glu-Val-Asp-aldehyde (Ac-DEVD-CHO), inhibited the apoptotic cell death of leiomyomal cells induced by SB. The Caspase 3-like activity in leiomyomal cells LM-1 and LM-2 increased after the addition of SB. Cytochrome C was released from mitochondria into the cytosol 8h after the addition of SB, and reached a peak at 16h. The peak of Cytochrome C release was earlier than that of Caspase 3-like activity. We concluded that SB inhibited the growth of the leiomyomal cells and induced apoptosis. The apoptosis of leiomyomal cells induced by SB was associated with the release of Cytochrome C from the mitochondria, followed by an increase in Caspase 3-like activity.

  7. Plant Lectin Can Target Receptors Containing Sialic Acid, Exemplified by Podoplanin, to Inhibit Transformed Cell Growth and Migration

    PubMed Central

    Shen, Yongquan; Acharya, Nimish K.; Han, Min; McNulty, Dean E.; Hasegawa, Hitoki; Hyodo, Toshinori; Senga, Takeshi; Geng, Jian-Guo; Kosciuk, Mary; Shin, Seung S.; Goydos, James S.; Temiakov, Dmitry; Nagele, Robert G.; Goldberg, Gary S.

    2012-01-01

    Cancer is a leading cause of death of men and women worldwide. Tumor cell motility contributes to metastatic invasion that causes the vast majority of cancer deaths. Extracellular receptors modified by α2,3-sialic acids that promote this motility can serve as ideal chemotherapeutic targets. For example, the extracellular domain of the mucin receptor podoplanin (PDPN) is highly O-glycosylated with α2,3-sialic acid linked to galactose. PDPN is activated by endogenous ligands to induce tumor cell motility and metastasis. Dietary lectins that target proteins containing α2,3-sialic acid inhibit tumor cell growth. However, anti-cancer lectins that have been examined thus far target receptors that have not been identified. We report here that a lectin from the seeds of Maackia amurensis (MASL) with affinity for O-linked carbohydrate chains containing sialic acid targets PDPN to inhibit transformed cell growth and motility at nanomolar concentrations. Interestingly, the biological activity of this lectin survives gastrointestinal proteolysis and enters the cardiovascular system to inhibit melanoma cell growth, migration, and tumorigenesis. These studies demonstrate how lectins may be used to help develop dietary agents that target specific receptors to combat malignant cell growth. PMID:22844530

  8. Successive Use of Non-Host Plant Proteinase Inhibitors Required for Effective Inhibition of Helicoverpa armigera Gut Proteinases and Larval Growth1

    PubMed Central

    Harsulkar, Abhay M.; Giri, Ashok P.; Patankar, Aparna G.; Gupta, Vidya S.; Sainani, Mohini N.; Ranjekar, Prabhakar K.; Deshpande, Vasanti V.

    1999-01-01

    We report on the efficacy of proteinase inhibitors (PIs) from three host plants (chickpea [Cicer arietinum], pigeonpea [Cajanus cajan], and cotton [Gossypium arboreum]) and three non-host (groundnut [Arachis hypogea], winged bean [Psophocarpus tetragonolobus], and potato [Solanum tuberosum]) in retarding the growth of Helicoverpa armigera larvae, a devastating pest of important crop plants. Enzyme assays and electrophoretic analysis of interaction of H. armigera gut proteinases (HGPs) with PIs revealed that non-host PIs inhibited HGP activity efficiently whereas host PIs were ineffective. In the electrophoretic assay, trypsin inhibitor activity bands were detected in all of the host and non-host plants, but HGP inhibitor activity bands were present only in non-host plants (except cotton in the host plant group). H. armigera larvae reared on a diet containing non-host PIs showed growth retardation, a reduction in total and trypsin-like proteinase activity, and the production of inhibitor-insensitive proteinases. Electrophoretic analysis of PI-induced HGP showed differential regulation of proteinase isoforms. Interestingly, HGP activity induced in response to dietary potato PI-II was inhibited by winged bean PIs. The optimized combination of potato PI-II and winged bean PIs identified in the present study and their proposed successive use has potential in developing H. armigera-resistant transgenic plants. PMID:10517841

  9. [Plant hormones, plant growth regulators].

    PubMed

    Végvári, György; Vidéki, Edina

    2014-06-29

    Plants seem to be rather defenceless, they are unable to do motion, have no nervous system or immune system unlike animals. Besides this, plants do have hormones, though these substances are produced not in glands. In view of their complexity they lagged behind animals, however, plant organisms show large scale integration in their structure and function. In higher plants, such as in animals, the intercellular communication is fulfilled through chemical messengers. These specific compounds in plants are called phytohormones, or in a wide sense, bioregulators. Even a small quantity of these endogenous organic compounds are able to regulate the operation, growth and development of higher plants, and keep the connection between cells, tissues and synergy between organs. Since they do not have nervous and immume systems, phytohormones play essential role in plants' life.

  10. [Plant hormones, plant growth regulators].

    PubMed

    Végvári, György; Vidéki, Edina

    2014-06-29

    Plants seem to be rather defenceless, they are unable to do motion, have no nervous system or immune system unlike animals. Besides this, plants do have hormones, though these substances are produced not in glands. In view of their complexity they lagged behind animals, however, plant organisms show large scale integration in their structure and function. In higher plants, such as in animals, the intercellular communication is fulfilled through chemical messengers. These specific compounds in plants are called phytohormones, or in a wide sense, bioregulators. Even a small quantity of these endogenous organic compounds are able to regulate the operation, growth and development of higher plants, and keep the connection between cells, tissues and synergy between organs. Since they do not have nervous and immume systems, phytohormones play essential role in plants' life. PMID:24954142

  11. Plant growth and cultivation.

    PubMed

    Podar, Dorina

    2013-01-01

    There is a variety of methods used for growing plants indoor for laboratory research. In most cases plant research requires germination and growth of plants. Often, people have adapted plant cultivation protocols to the conditions and materials at hand in their own laboratory and growth facilities. Here I will provide a guide for growing some of the most frequently used plant species for research, i.e., Arabidopsis thaliana, barley (Hordeum vulgare) and rice (Oryza sativa). However, the methods presented can be used for other plant species as well, especially if they are related to the above-mentioned species. The presented methods include growing plants in soil, hydroponics, and in vitro on plates. This guide is intended as a starting point for those who are just beginning to work on any of the above-mentioned plant species. Methods presented are to be taken as suggestive and modification can be made according to the conditions existing in the host laboratory. PMID:23073874

  12. Plant growth and cultivation.

    PubMed

    Podar, Dorina

    2013-01-01

    There is a variety of methods used for growing plants indoor for laboratory research. In most cases plant research requires germination and growth of plants. Often, people have adapted plant cultivation protocols to the conditions and materials at hand in their own laboratory and growth facilities. Here I will provide a guide for growing some of the most frequently used plant species for research, i.e., Arabidopsis thaliana, barley (Hordeum vulgare) and rice (Oryza sativa). However, the methods presented can be used for other plant species as well, especially if they are related to the above-mentioned species. The presented methods include growing plants in soil, hydroponics, and in vitro on plates. This guide is intended as a starting point for those who are just beginning to work on any of the above-mentioned plant species. Methods presented are to be taken as suggestive and modification can be made according to the conditions existing in the host laboratory.

  13. Transgenic Cotton Plants Expressing Double-stranded RNAs Target HMG-CoA Reductase (HMGR) Gene Inhibits the Growth, Development and Survival of Cotton Bollworms

    PubMed Central

    Tian, Geng; Cheng, Linlin; Qi, Xuewei; Ge, Zonghe; Niu, Changying; Zhang, Xianlong; Jin, Shuangxia

    2015-01-01

    RNA interference (RNAi) has been developed as a powerful technique in the research of functional genomics as well as plant pest control. In this report, double-stranded RNAs (dsRNA) targeting 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) gene, which catalyze a rate-limiting enzymatic reaction in the mevalonate pathway of juvenile hormone (JH) synthesis in cotton bollworm, was expressed in cotton plants via Agrobacterium tumefaciens-mediated transformation. PCR and Sothern analysis revealed the integration of HMGR gene into cotton genome. RT-PCR and qRT-PCR confirmed the high transcription level of dsHMGR in transgenic cotton lines. The HMGR expression both in transcription and translation level was significantly downregulated in cotton bollworms (helicoverpa armigera) larvae after feeding on the leaves of HMGR transgenic plants. The transcription level of HMGR gene in larvae reared on transgenic cotton leaves was as much as 80.68% lower than that of wild type. In addition, the relative expression level of vitellogenin (Vg, crucial source of nourishment for offspring embryo development) gene was also reduced by 76.86% when the insect larvae were fed with transgenic leaves. The result of insect bioassays showed that the transgenic plant harboring dsHMGR not only inhibited net weight gain but also delayed the growth of cotton bollworm larvae. Taken together, transgenic cotton plant expressing dsRNAs successfully downregulated HMGR gene and impaired the development and survival of target insect, which provided more option for plant pest control. PMID:26435695

  14. Plant perceptions of plant growth-promoting Pseudomonas.

    PubMed Central

    Preston, Gail M

    2004-01-01

    Plant-associated Pseudomonas live as saprophytes and parasites on plant surfaces and inside plant tissues. Many plant-associated Pseudomonas promote plant growth by suppressing pathogenic micro-organisms, synthesizing growth-stimulating plant hormones and promoting increased plant disease resistance. Others inhibit plant growth and cause disease symptoms ranging from rot and necrosis through to developmental dystrophies such as galls. It is not easy to draw a clear distinction between pathogenic and plant growth-promoting Pseudomonas. They colonize the same ecological niches and possess similar mechanisms for plant colonization. Pathogenic, saprophytic and plant growth-promoting strains are often found within the same species, and the incidence and severity of Pseudomonas diseases are affected by environmental factors and host-specific interactions. Plants are faced with the challenge of how to recognize and exclude pathogens that pose a genuine threat, while tolerating more benign organisms. This review examines Pseudomonas from a plant perspective, focusing in particular on the question of how plants perceive and are affected by saprophytic and plant growth-promoting Pseudomonas (PGPP), in contrast to their interactions with plant pathogenic Pseudomonas. A better understanding of the molecular basis of plant-PGPP interactions and of the key differences between pathogens and PGPP will enable researchers to make more informed decisions in designing integrated disease-control strategies and in selecting, modifying and using PGPP for plant growth promotion, bioremediation and biocontrol. PMID:15306406

  15. Plant growth promoting rhizobacterium

    SciTech Connect

    Doktycz, Mitchel John; Pelletier, Dale A.; Schadt, Christopher Warren; Tuskan, Gerald A.; Weston, David

    2015-08-11

    The present invention is directed to the Pseudomonas fluorescens strain GM30 deposited under ATCC Accession No. PTA-13340, compositions containing the GM30 strain, and methods of using the GM30 strain to enhance plant growth and/or enhance plant resistance to pathogens.

  16. Microgravity Plant Growth Demonstration

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Two visitors watch a TV monitor showing plant growth inside a growth chamber designed for operation aboard the Space Shuttle as part of NASA's Space Product Development program. The exhibit, featuring work by the Wisconsin Center for Space Automation and Robotics, was at AirVenture 2000 sponsored by the Experimental Aircraft Association in Oshkosh, WI.

  17. Alfalfa endophytes as novel sources of antimicrobial compounds that inhibit the growth of human and plant pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fungal endophytes may contribute to plant health and disease protection, yet little is known about their various roles in alfalfa. Also, endophytes from several plant species produce novel antimicrobial compounds that may be useful clinically. We isolated endophytic fungi from over 50 samples from s...

  18. Natural plant products inhibits growth and alters the swarming motility, biofilm formation, and expression of virulence genes in enteroaggregative and enterohemorrhagic Escherichia coli.

    PubMed

    García-Heredia, Alam; García, Santos; Merino-Mascorro, José Ángel; Feng, Peter; Heredia, Norma

    2016-10-01

    The purpose of this study was to determine the effects of plant products on the growth, swarming motility, biofilm formation and virulence gene expression in enterohemorrhagic Escherichia coli O157:H7 and enteroaggregative E. coli strain 042 and a strain of O104:H4 serotype. Extracts of Lippia graveolens and Haematoxylon brassiletto, and carvacrol, brazilin were tested by an antimicrobial microdilution method using citral and rifaximin as controls. All products showed bactericidal activity with minimal bactericidal concentrations ranging from 0.08 to 8.1 mg/ml. Swarming motility was determined in soft LB agar. Most compounds reduced swarming motility by 7%-100%; except carvacrol which promoted motility in two strains. Biofilm formation studies were done in microtiter plates. Rifaximin inhibited growth and reduced biofilm formation, but various concentrations of other compounds actually induced biofilm formation. Real time PCR showed that most compounds decreased stx2 expression. The expression of pic and rpoS in E. coli 042 were suppressed but in E. coli O104:H4 they varied depending on compounds. In conclusion, these extracts affect E. coli growth, swarming motility and virulence gene expression. Although these compounds were bactericidal for pathogenic E. coli, sublethal concentrations had varied effects on phenotypic and genotypic traits, and some increased virulence gene expression.

  19. Plant Growth Facility (PGF)

    NASA Technical Reports Server (NTRS)

    1998-01-01

    In a microgravity environment aboard the Space Shuttle Columbia Life and Microgravity Mission STS-78, compression wood formation and hence altered lignin deposition and cell wall structure, was induced upon mechanically bending the stems of the woody gymnosperms, Douglas fir (Pseudotsuga menziesii) and loblolly pine (Pinus taeda). Although there was significant degradation of many of the plant specimens in space-flight due to unusually high temperatures experienced during the mission, it seems evident that gravity had little or no effect on compression wood formation upon bending even in microgravity. Instead, it apparently results from alterations in the stress gradient experienced by the plant itself during bending under these conditions. This preliminary study now sets the stage for long-term plant growth experiments to determine whether compression wood formation can be induced in microgravity during phototropic-guided realignment of growing woody plant specimens, in the absence of any externally provided stress and strain.

  20. [Effect of alcoholic extracts of wild plants on the inhibition of growth of Aspergillus flavus, Aspergillus niger, Penicillium chrysogenum, Penicillium expansum, Fusarium moniliforme and Fusarium poae moulds].

    PubMed

    Tequida-Meneses, Martín; Cortez-Rocha, Mario; Rosas-Burgos, Ema Carina; López-Sandoval, Susana; Corrales-Maldonado, Consuelo

    2002-06-01

    Fungicidal activity of wild plants Larrea tridentata, Karwinskia humboldtiana, Ricinus communis, Eucalyptus globulus, Ambrosia ambrosioides, Nicotiana glauca, Ambrosia confertiflora, Datura discolor, Baccharis glutinosa, Proboscidea parviflora, Solanum rostratum, Jatropha cinerea, Salpianthus macrodonthus y Sarcostemma cynanchoides was evaluated against the moulds species Aspergillus flavus, Aspergillus niger, Penicillium chrysogenum, Penicillium expansum, Fusarium poae y Fusarium moniliforme moulds species. Alcoholic extracts 6% (w/v) were prepared using six grams of dried plant powders (leaves and stems) and alcohol (70% ethanol or 70% methanol). A spore suspension (1x10(6); ufc/ml) of each mould was prepared by adding saline solution (0.85%) and 0.1% tween 80. The extracts were mixed with Czapeck yeast agar (CYA) at 45-50 degrees C in 1:10 relation on Petri dishes. Triplicate Petri dishes of each treatment and for each mould were centrally inoculated and three Petri dishes were used without treatment as controls. The inoculated dishes and controls were incubated at 25 +/- 2 degrees C for eight days. The incubated dishes were examined each 48 h and after the colony diameter (radial growth) was measured. Two mould species were controlled by L. tridentata, B. glutinosa and P. parviflora. Extracts of L. tridentata in methanol or ethanol at 41.5-100% inhibited all six species of moulds.

  1. STUDIES ON PNEUMOCOCCUS GROWTH INHIBITION

    PubMed Central

    Robertson, Oswald H.; Sia, Richard H. P.

    1924-01-01

    Somewhat discordant results which have been reported by others who have investigated the property of the whole blood of resistant animals to cause inhibition of growth or death of pneumococci have led us to investigate this matter and to develop a new technique in which the conditions as they are present in the animal body are more nearly imitated. The observations already made have rendered it probable that phagocytosis plays some rôle in any destructive power for pneumococcus which whole blood possesses. We have, therefore, employed mixtures of serum and leucocytes in our tests, since when blood is coagulated the conditions become highly artificial. Furthermore, in order to imitate more nearly the conditions in the circulating blood the mixtures have been constantly, though gently, agitated. For this purpose a specially devised apparatus has been employed. The mixtures of serum and leucocytes have been inoculated with varying numbers of pneumococci in the active growth phase and after varying intervals of time the tubes containing the mixtures of serum, leucocytes, and bacteria have been opened, examined microscopically, and cultures made. Employing this technique it has been found that the growth of pneumococci having low virulence for cats is markedly inhibited in mixtures of cat serum and cat leucocytes. It was impossible to recover pneumococci from the tubes showing no apparent growth, either when the contents were transplanted into various kinds of culture media, or when the contents were injected into mice of a variety highly susceptible to pneumococcus infection. 10,000 times the number of pneumococci sufficient ordinarily to kill a mouse failed to do so after a 24 hour sojourn in the cat serum-leucocyte mixture. Mixtures of dog serum and leucocytes exert a similar action. The serum and leucocytes of animals susceptible to pneumococcus infection (rabbits and guinea pigs,) on the other hand, failed to injure pneumococci even in extremely small quantities

  2. Well having inhibited microbial growth

    DOEpatents

    Lee, Brady D.; Dooley, Kirk J.

    2006-08-15

    The invention includes methods of inhibiting microbial growth in a well. A packing material containing a mixture of a first material and an antimicrobial agent is provided to at least partially fill a well bore. One or more access tubes are provided in an annular space around a casing within the well bore. The access tubes have a first terminal opening located at or above a ground surface and have a length that extends from the first terminal opening at least part of the depth of the well bore. The access tubes have a second terminal opening located within the well bore. An antimicrobial material is supplied into the well bore through the first terminal opening of the access tubes. The invention also includes well constructs.

  3. (Plant growth with limited water)

    SciTech Connect

    Not Available

    1991-01-01

    The work supported by DOE in the last year built on our earlier findings that stem growth in soybean subjected to limited water is inhibited first by a physical limitation followed in a few hours by metabolic changes that reduce the extensibility of the cell walls. With time, there is modest recovery in extensibility and a 28kD protein accumulates in the walls of the growth-affected cells. A 31kD protein that was 80% similar in amino acid sequence also was present but did not accumulate in the walls of the stem cells. Explorations of the mRNA for these proteins showed that the mRNA for the 28kD protein increased in the shoot in response to water deprivation but the mRNA for the 31kD protein did not accumulate. In contrast, the roots continued to grow and the mRNA for the 31kD protein accumulated but the mRNA for the 28kD protein was undetectable. We also explored how growth occurs in the absence of an external water supply. We found that, under these conditions, internal water is mobilized from surrounding nongrowing or slowly growing tissues and is used by rapidly growing cells. We showed that a low water potential is normally present in the enlarging tissues and is the likely force that extracts water from the surrounding tissues. We found that it involved a gradient in water potential that extended from the xylem to the outlying cells in the enlarging region and was not observed in the slowly growing basal tissue of the stems of the same plant. The gradient was measured directly with single cell determinations of turgor and osmotic potential in intact plants. The gradient may explain instances of growth inhibition with limited water when there is no change in the turgor of the enlarging cells. 17 refs.

  4. Students' Ideas about Plants and Plant Growth

    ERIC Educational Resources Information Center

    Barman, Charles R.; Stein, Mary; McNair, Shannan; Barman, Natalie S.

    2006-01-01

    Because the National Science Education Standards (1996) outline specific things K-8 students should know about plants, and previous data indicated that elementary students had difficulty understanding some major ideas about plants and plant growth, the authors of this article thought it appropriate to initiate an investigation to determine the…

  5. Chemical Control of Plant Growth.

    ERIC Educational Resources Information Center

    Agricultural Research Center (USDA), Beltsville, MD.

    Seven experiments are presented in this Science Study Aid to help students investigate the control of plant growth with chemicals. Plant growth regulators, weed control, and chemical pruning are the topics studied in the experiments which are based on investigations that have been and are being conducted at the U. S. Agricultural Research Center,…

  6. Phytochrome, plant growth and flowering

    NASA Technical Reports Server (NTRS)

    King, R. W.; Bagnall, D. J.

    1994-01-01

    Attempts to use artificially lit cabinets to grow plants identical to those growing in sunlight have provided compelling evidence of the importance of light quality for plant growth. Changing the balance of red (R) to far-red (FR) radiation, but with a fixed photosynthetic input can shift the phytochrome photoequilibrium in a plant and generate large differences in plant growth. With FR enrichment the plants elongate, and may produce more leaf area and dry matter. Similar morphogenic responses are also obtained when light quality is altered only briefly (15-30 min) at the end-of-the-day. Conversely, for plants grown in natural conditions the response of plant form to selective spectral filtering has again shown that red and far-red wavebands are important as found by Kasperbauer and coworkers. Also, where photosynthetic photon flux densities (PPFD) of sunlight have been held constant, the removal of far-red alone alters plant growth. With FR depletion plants grown in sunlight are small, more branched and darker green. Here we examine the implications for plant growth and flowering when the far-red composition of incident radiation in plant growth chambers is manipulated.

  7. Bean Plants: A Growth Experience

    ERIC Educational Resources Information Center

    West, Donna

    2004-01-01

    Teaching plant growth to seventh-grade life science students has been interesting for the author because she grew up in a rural area and always had to help in the garden. She made many assumptions about what her rural and suburban students knew. One year she decided to have them grow plants to observe the roots, stems, leaves, flowers, and fruit…

  8. A Simple Plant Growth Analysis.

    ERIC Educational Resources Information Center

    Oxlade, E.

    1985-01-01

    Describes the analysis of dandelion peduncle growth based on peduncle length, epidermal cell dimensions, and fresh/dry mass. Methods are simple and require no special apparatus or materials. Suggests that limited practical work in this area may contribute to students' lack of knowledge on plant growth. (Author/DH)

  9. Decreased growth-induced water potential: A primary cause of growth inhibition at low water potentials

    SciTech Connect

    Nonami, Hiroshi; Wu, Yajun; Boyer, J.S.

    1997-06-01

    Cell enlargement depends on a growth-induced difference in water potential to move water into the cells. Water deficits decrease this potential difference and inhibit growth. To investigate whether the decrease causes the growth inhibition, pressure was applied to the roots of soybean seedlings and the growth and potential difference were monitored in the stems. In water-limited plants, the inhibited stem growth increased when the roots were pressurized and it reverted to the previous rate when the pressure was released. The pressure around the roots was perceived as an increased turgor in the stem in small cells next to the xylem, but not in outlying cortical cells. This local effect implied that water transport was impeded by the small cells. The diffusivity for water was much less in the small cells than in the outlying cells. The small cells thus were a barrier that caused the growth-induced potential difference to be large during rapid growth, but to reverse locally during the early part of a water deficit. Such a barrier may be a frequent property of meristems. Because stem growth responded to the pressure-induced recovery of the potential difference across this barrier, we conclude that a decrease in the growth-induced potential difference was a primary cause of the inhibition.

  10. Phytotoxicity of nanoparticles: inhibition of seed germination and root growth.

    PubMed

    Lin, Daohui; Xing, Baoshan

    2007-11-01

    Plants need to be included to develop a comprehensive toxicity profile for nanoparticles. Effects of five types of nanoparticles (multi-walled carbon nanotube, aluminum, alumina, zinc, and zinc oxide) on seed germination and root growth of six higher plant species (radish, rape, ryegrass, lettuce, corn, and cucumber) were investigated. Seed germination was not affected except for the inhibition of nanoscale zinc (nano-Zn) on ryegrass and zinc oxide (nano-ZnO) on corn at 2000 mg/L. Inhibition on root growth varied greatly among nanoparticles and plants. Suspensions of 2000 mg/L nano-Zn or nano-ZnO practically terminated root elongation of the tested plant species. Fifty percent inhibitory concentrations (IC50) of nano-Zn and nano-ZnO were estimated to be near 50mg/L for radish, and about 20mg/L for rape and ryegrass. The inhibition occurred during the seed incubation process rather than seed soaking stage. These results are significant in terms of use and disposal of engineered nanoparticles.

  11. Menaquinone analogs inhibit growth of bacterial pathogens.

    PubMed

    Schlievert, Patrick M; Merriman, Joseph A; Salgado-Pabón, Wilmara; Mueller, Elizabeth A; Spaulding, Adam R; Vu, Bao G; Chuang-Smith, Olivia N; Kohler, Petra L; Kirby, John R

    2013-11-01

    Gram-positive bacteria cause serious human illnesses through combinations of cell surface and secreted virulence factors. We initiated studies with four of these organisms to develop novel topical antibacterial agents that interfere with growth and exotoxin production, focusing on menaquinone analogs. Menadione, 1,4-naphthoquinone, and coenzymes Q1 to Q3 but not menaquinone, phylloquinone, or coenzyme Q10 inhibited the growth and to a greater extent exotoxin production of Staphylococcus aureus, Bacillus anthracis, Streptococcus pyogenes, and Streptococcus agalactiae at concentrations of 10 to 200 μg/ml. Coenzyme Q1 reduced the ability of S. aureus to cause toxic shock syndrome in a rabbit model, inhibited the growth of four Gram-negative bacteria, and synergized with another antimicrobial agent, glycerol monolaurate, to inhibit S. aureus growth. The staphylococcal two-component system SrrA/B was shown to be an antibacterial target of coenzyme Q1. We hypothesize that menaquinone analogs both induce toxic reactive oxygen species and affect bacterial plasma membranes and biosynthetic machinery to interfere with two-component systems, respiration, and macromolecular synthesis. These compounds represent a novel class of potential topical therapeutic agents.

  12. Abscisic acid inhibits root growth in Arabidopsis through ethylene biosynthesis.

    PubMed

    Luo, Xingju; Chen, Zhizhong; Gao, Junping; Gong, Zhizhong

    2014-07-01

    When first discovered in 1963, abscisic acid (ABA) was called abscisin II because it promotes abscission. Later, researchers found that ABA accelerates abscission via ethylene. In Arabidopsis, previous studies have shown that high concentrations of ABA inhibit root growth through ethylene signaling but not ethylene production. In the present study in Arabidopsis, we found that ABA inhibits root growth by promoting ethylene biosynthesis. The ethylene biosynthesis inhibitor L-α-(2-aminoethoxyvinyl)-glycine reduces ABA inhibition of root growth, and multiple mutants of ACS (1-aminocyclopropane-1-carboxylate synthase) are more resistant to ABA in terms of root growth than the wild-type is. Two ABA-activated calcium-dependent protein kinases, CPK4 and CPK11, phosphorylate the C-terminus of ACS6 and increase the stability of ACS6 in ethylene biosynthesis. Plants expressing an ACS6 mutant that mimics the phosphorylated form of ACS6 produce more ethylene than the wild-type. Our results reveal an important mechanism by which ABA promotes ethylene production. This mechanism may be highly conserved among higher plants.

  13. Polyoxin D inhibits growth of zoopathogenic fungi.

    PubMed Central

    Becker, J M; Covert, N L; Shenbagamurthi, P; Steinfeld, A S; Naider, F

    1983-01-01

    We demonstrated that polyoxin D at millimolar concentrations caused marked morphological alterations of the human pathogens Candida albicans and Cryptococcus neoformans. C. albicans incubated in the presence of this drug grew in long chains that were severely swollen. Polyoxin D inhibited the growth of C. neoformans and killed cells of both the yeast and the hyphal phase of C. albicans. These observations give the first evidence that polyoxin antibiotics can kill zoopathogenic fungi. Images PMID:6351734

  14. Mechanical regulation of plant growth and development

    NASA Technical Reports Server (NTRS)

    Mitchell, C. A.

    1984-01-01

    Soybean and eggplant grown and shaken in a greenhouse exhibited decreased internode length, internode diameter, leaf area, and fresh and dry weight of roots and shoots in much the same way as outdoor-exposed plants. Perhaps more important than decreased dimensions of plant parts resulting from periodic seismic treatment is the inhibition of photosynthetic productivity that accompanies this stress. Soybeam plants briefly shaken or rubbed twice daily experienced a decrease in relative as well as absolute growth rate compared to that of undisturbed controls. Growth dynamics analysis revealed that virtually all of the decline in relative growth rate (RGR) was due to a decline in net assimilation rate (NAR), but not in leaf area ratio (LAR). Lower NAR suggests that the stress-induced decrease in dry weight gain is due to a decline in photosynthetic efficiency. Possible effects on stomatal aperture was investigated by measuring rates of whole plant transpiration as a function of seismo-stress, and a transitory decrease followed by a gradual, partial recovery was detected.

  15. Ormeloxifene efficiently inhibits ovarian cancer growth

    PubMed Central

    Maher, Diane M.; Khan, Sheema; Nordquist, Jordan; Ebeling, Mara C.; Bauer, Nichole A.; Kopel, Lucas; Singh, Man Mohan; Halaweish, Fathi; Bell, Maria C.; Jaggi, Meena; Chauhan, Subhash C.

    2014-01-01

    Ovarian cancer continues to be a leading cause of cancer related deaths for women. Anticancer agents effective against chemo-resistant cells are greatly needed for ovarian cancer treatment. Repurposing drugs currently in human use is an attractive strategy for developing novel cancer treatments with expedited translation into clinical trials. Therefore, we examined whether ormeloxifene (ORM), a non-steroidal Selective Estrogen Receptor Modulator (SERM) currently used for contraception, is therapeutically effective at inhibiting ovarian cancer growth. We report that ORM treatment inhibits cell growth and induces apoptosis in ovarian cancer cell lines, including cell lines resistant to cisplatin. Furthermore, ORM treatment decreases Akt phosphorylation, increases p53 phosphorylation, and modulates the expression and localization patterns of p27, cyclin E, cyclin D1, and CDK2. In a pre-clinical xenograft mouse ORM treatment significantly reduces tumorigenesis and metastasis. These results indicate that ORM effectively inhibits the growth of cisplatin resistant ovarian cancer cells. ORM is currently in human use and has an established record of patient safety. Our encouraging in vitro and pre-clinical in vivo findings indicate that ORM is a promising candidate for the treatment of ovarian cancer. PMID:25306892

  16. Growth suppression of colorectal cancer by plant-derived multiple mAb CO17-1A × BR55 via inhibition of ERK1/2 phosphorylation.

    PubMed

    Kwak, Dong Hoon; Moussavou, Ghislain; Lee, Ju Hyoung; Heo, Sung Youn; Ko, Kisung; Hwang, Kyung-A; Jekal, Seung-Joo; Choo, Young-Kug

    2014-01-01

    We have generated the transgenic Tabaco plants expressing multiple monoclonal antibody (mAb) CO7-1A × BR55 by cross-pollinating with mAb CO17-1A and mAb BR55. We have demonstrated the anti-cancer effect of plant-derived multiple mAb CO17-1A × BR55. We find that co-treatment of colorectal mAbs (anti-epithelial cellular adhesion molecule (EpCAM), plant-derived monoclonal antibody (mAb(P)) CO17-1A and mAb(P) CO17-1A × BR55) with RAW264.7 cells significantly inhibited the cell growth in SW620 cancer cells. In particular, multi mAb(P) CO17-1A × BR55 significantly and efficiently suppressed the growth of SW620 cancer cells compared to another mAbs. Apoptotic death-positive cells were significantly increased in the mAb(P) CO17-1A × BR55-treated. The mAb(P) CO17-1A × BR55 treatment significantly decreased the expression of B-Cell lymphoma-2 (BCl-2), but the expression of Bcl-2-associated X protein (Bax), and cleaved caspase-3 were markedly increased. In vivo, the mAb(P) CO17-1A × BR55 significantly and efficiently inhibited the growth of colon tumors compared to another mAbs. The apoptotic cell death and inhibition of pro-apoptotic proteins expression were highest by treatment with mAb(P) CO17-1A × BR55. In addition, the mAb(P) CO17-1A × BR55 significantly inhibited the extracellular signal-regulated kinase 1 and 2 (ERK1/2) phosphorylation in cancer cells and tumors. Therefore, this study results suggest that multiple mAb(P) CO17-1A × BR55 has a significant effect on apoptosis-mediated anticancer by suppression of ERK1/2 phosphorylation in colon cancer compared to another mAbs. In light of these results, further clinical investigation should be conducted on mAb(P) CO17-1A × BR55 to determine its possible chemopreventive and/or therapeutic efficacy against human colon cancer. PMID:25405740

  17. Growth suppression of colorectal cancer by plant-derived multiple mAb CO17-1A × BR55 via inhibition of ERK1/2 phosphorylation.

    PubMed

    Kwak, Dong Hoon; Moussavou, Ghislain; Lee, Ju Hyoung; Heo, Sung Youn; Ko, Kisung; Hwang, Kyung-A; Jekal, Seung-Joo; Choo, Young-Kug

    2014-11-14

    We have generated the transgenic Tabaco plants expressing multiple monoclonal antibody (mAb) CO7-1A × BR55 by cross-pollinating with mAb CO17-1A and mAb BR55. We have demonstrated the anti-cancer effect of plant-derived multiple mAb CO17-1A × BR55. We find that co-treatment of colorectal mAbs (anti-epithelial cellular adhesion molecule (EpCAM), plant-derived monoclonal antibody (mAb(P)) CO17-1A and mAb(P) CO17-1A × BR55) with RAW264.7 cells significantly inhibited the cell growth in SW620 cancer cells. In particular, multi mAb(P) CO17-1A × BR55 significantly and efficiently suppressed the growth of SW620 cancer cells compared to another mAbs. Apoptotic death-positive cells were significantly increased in the mAb(P) CO17-1A × BR55-treated. The mAb(P) CO17-1A × BR55 treatment significantly decreased the expression of B-Cell lymphoma-2 (BCl-2), but the expression of Bcl-2-associated X protein (Bax), and cleaved caspase-3 were markedly increased. In vivo, the mAb(P) CO17-1A × BR55 significantly and efficiently inhibited the growth of colon tumors compared to another mAbs. The apoptotic cell death and inhibition of pro-apoptotic proteins expression were highest by treatment with mAb(P) CO17-1A × BR55. In addition, the mAb(P) CO17-1A × BR55 significantly inhibited the extracellular signal-regulated kinase 1 and 2 (ERK1/2) phosphorylation in cancer cells and tumors. Therefore, this study results suggest that multiple mAb(P) CO17-1A × BR55 has a significant effect on apoptosis-mediated anticancer by suppression of ERK1/2 phosphorylation in colon cancer compared to another mAbs. In light of these results, further clinical investigation should be conducted on mAb(P) CO17-1A × BR55 to determine its possible chemopreventive and/or therapeutic efficacy against human colon cancer.

  18. Growth Suppression of Colorectal Cancer by Plant-Derived Multiple mAb CO17-1A × BR55 via Inhibition of ERK1/2 Phosphorylation

    PubMed Central

    Kwak, Dong Hoon; Moussavou, Ghislain; Lee, Ju Hyoung; Heo, Sung Youn; Ko, Kisung; Hwang, Kyung-A; Jekal, Seung-Joo; Choo, Young-Kug

    2014-01-01

    We have generated the transgenic Tabaco plants expressing multiple monoclonal antibody (mAb) CO7-1A × BR55 by cross-pollinating with mAb CO17-1A and mAb BR55. We have demonstrated the anti-cancer effect of plant-derived multiple mAb CO17-1A × BR55. We find that co-treatment of colorectal mAbs (anti-epithelial cellular adhesion molecule (EpCAM), plant-derived monoclonal antibody (mAbP) CO17-1A and mAbP CO17-1A × BR55) with RAW264.7 cells significantly inhibited the cell growth in SW620 cancer cells. In particular, multi mAbP CO17-1A × BR55 significantly and efficiently suppressed the growth of SW620 cancer cells compared to another mAbs. Apoptotic death-positive cells were significantly increased in the mAbP CO17-1A × BR55-treated. The mAbP CO17-1A × BR55 treatment significantly decreased the expression of B-Cell lymphoma-2 (BCl-2), but the expression of Bcl-2-associated X protein (Bax), and cleaved caspase-3 were markedly increased. In vivo, the mAbP CO17-1A × BR55 significantly and efficiently inhibited the growth of colon tumors compared to another mAbs. The apoptotic cell death and inhibition of pro-apoptotic proteins expression were highest by treatment with mAbP CO17-1A × BR55. In addition, the mAbP CO17-1A × BR55 significantly inhibited the extracellular signal-regulated kinase 1 and 2 (ERK1/2) phosphorylation in cancer cells and tumors. Therefore, this study results suggest that multiple mAbP CO17-1A × BR55 has a significant effect on apoptosis-mediated anticancer by suppression of ERK1/2 phosphorylation in colon cancer compared to another mAbs. In light of these results, further clinical investigation should be conducted on mAbP CO17-1A × BR55 to determine its possible chemopreventive and/or therapeutic efficacy against human colon cancer. PMID:25405740

  19. Plant growth-promoting bacterial endophytes.

    PubMed

    Santoyo, Gustavo; Moreno-Hagelsieb, Gabriel; Orozco-Mosqueda, Ma del Carmen; Glick, Bernard R

    2016-02-01

    Bacterial endophytes ubiquitously colonize the internal tissues of plants, being found in nearly every plant worldwide. Some endophytes are able to promote the growth of plants. For those strains the mechanisms of plant growth-promotion known to be employed by bacterial endophytes are similar to the mechanisms used by rhizospheric bacteria, e.g., the acquisition of resources needed for plant growth and modulation of plant growth and development. Similar to rhizospheric plant growth-promoting bacteria, endophytic plant growth-promoting bacteria can act to facilitate plant growth in agriculture, horticulture and silviculture as well as in strategies for environmental cleanup (i.e., phytoremediation). Genome comparisons between bacterial endophytes and the genomes of rhizospheric plant growth-promoting bacteria are starting to unveil potential genetic factors involved in an endophytic lifestyle, which should facilitate a better understanding of the functioning of bacterial endophytes.

  20. (Plant growth with limited water)

    SciTech Connect

    Not Available

    1992-01-01

    When water is in short supply, soybean stem growth is inhibited by a physical limitation followed in a few hours by metabolic changes that reduce the extensibility of the cell walls. The extensibility then becomes the main limitation. With time, there is a modest recovery in extensibility along with an accumulation of a 28kD protein in the walls of the growth-affected cells. A 3lkD protein that was 80% similar in amino acid sequence also was present but did not accumulate in the walls of the stem cells. In the stem, growth was inhibited and the mRNA for the 28kD protein increased in response to water deprivation but the mRNA for the 3 1 kD protein did not. The roots continued to grow and the mRNA for the 28kD protein did not accumulate but the mRNA for the 3lkD protein did. Thus, there was a tissuespecific response of gene expression that correlated with the contrasting growth response to low water potential in the same seedlings. Further work using immunogold labeling, fluorescence labeling, and western blotting gave evidence that the 28kD protein is located in the cell wall as well as several compartments in the cytoplasm. Preliminary experiments indicate that the 28kD protein is a phosphatase.

  1. Water-Conserving Plant-Growth System

    NASA Technical Reports Server (NTRS)

    Dreschel, Thomas W.; Brown, Christopher S.

    1993-01-01

    Report presents further information about plant-growth apparatus described in "Tubular Membrane Plant-Growth Unit" (KSC-11375). Apparatus provides nutrient solution to roots of seedlings without flooding. Conserves water by helping to prevent evaporation from plant bed. Solution supplied only as utilized by seedlings. Device developed for supporting plant growth in space, also has applications for growing plants with minimum of water, such as in arid environments.

  2. Selenium nanoparticles inhibit Staphylococcus aureus growth.

    PubMed

    Tran, Phong A; Webster, Thomas J

    2011-01-01

    Staphylococcus aureus is a key bacterium commonly found in numerous infections. S. aureus infections are difficult to treat due to their biofilm formation and documented antibiotic resistance. While selenium has been used for a wide range of applications including anticancer applications, the effects of selenium nanoparticles on microorganisms remain largely unknown to date. The objective of this in vitro study was thus to examine the growth of S. aureus in the presence of selenium nanoparticles. Results of this study provided the first evidence of strongly inhibited growth of S. aureus in the presence of selenium nanoparticles after 3, 4, and 5 hours at 7.8, 15.5, and 31 μg/mL. The percentage of live bacteria also decreased in the presence of selenium nanoparticles. Therefore, this study suggests that selenium nanoparticles may be used to effectively prevent and treat S. aureus infections and thus should be further studied for such applications.

  3. Salicylate Accumulation Inhibits Growth at Chilling Temperature in Arabidopsis1

    PubMed Central

    Scott, Ian M.; Clarke, Shannon M.; Wood, Jacqueline E.; Mur, Luis A.J.

    2004-01-01

    The growth of Arabidopsis plants in chilling conditions could be related to their levels of salicylic acid (SA). Plants with the SA hydroxylase NahG transgene grew at similar rates to Col-0 wild types at 23°C, and growth of both genotypes was slowed by transfer to 5°C. However, at 5°C, NahG plants displayed relative growth rates about one-third greater than Col-0, so that by 2 months NahG plants were typically 2.7-fold larger. This resulted primarily from greater cell expansion in NahG rosette leaves. Specific leaf areas and leaf area ratios remained similar in both genotypes. Net assimilation rates were similar in both genotypes at 23°C, but higher in NahG at 5°C. Chlorophyll fluorescence measurements revealed no PSII photodamage in chilled leaves of either genotype. Col-0 shoots at 5°C accumulated SA, particularly in glucosylated form. SA in NahG shoots showed similar tendencies at 5°C, but at greatly depleted levels. Catechol was not detected as a metabolite of the NahG transgene product. We also examined growth and SA levels in SA signaling and metabolism mutants at 5°C. The partially SA-insensitive npr1 mutant displayed growth intermediate between NahG and Col-0, while the SA-deficient eds5 mutant behaved like NahG. In contrast, the cpr1 mutant at 5°C accumulated very high levels of SA and its growth was much more inhibited than wild type. At both temperatures, cpr1 was the only SA-responsive genotype in which oxidative damage (measured as thiobarbituric acid-reactive substances) was significantly different from wild type. PMID:15173571

  4. Rapamycin inhibits the growth of glioblastoma.

    PubMed

    Arcella, Antonietta; Biagioni, Francesca; Antonietta Oliva, Maria; Bucci, Domenico; Frati, Alessandro; Esposito, Vincenzo; Cantore, Giampaolo; Giangaspero, Felice; Fornai, Francesco

    2013-02-01

    The molecular target of rapamycin (mTOR) is up-regulated in glioblastoma (GBM) and this is associated with the rate of cell growth, stem cell proliferation and disease relapse. Rapamycin is a powerful mTOR inhibitor and strong autophagy inducer. Previous studies analyzed the effects of rapamycin in GBM cell lines. However, to our knowledge, no experiment was carried out to evaluate the effects of rapamycin neither in primary cells derived from GBM patients nor in vivo in brain GBM xenograft. These data are critical to get a deeper insight into the effects of such adjuvant therapy in GBM patients. In the present study, various doses of rapamycin were tested in primary cell cultures from GBM patients. These effects were compared with that obtained by the same doses of rapamycin in GBM cell lines (U87Mg). The effects of rapamycin were also evaluated in vivo, in brain tumors developed from mouse xenografts. Rapamycin, starting at the dose of 10nm inhibited cell growth both in U87Mg cell line and primary cell cultures derived from various GBM patients. When administered in vivo to brain xenografts in nude mice rapamycin almost doubled the survival time of mice and inhibited by more than 95% of tumor volume. PMID:23261661

  5. LED Systems Target Plant Growth

    NASA Technical Reports Server (NTRS)

    2010-01-01

    To help develop technologies for growing edible biomass (food crops) in space, Kennedy Space Center partnered with Orbital Technologies Corporation (ORBITEC), of Madison, Wisconsin, through the Small Business Innovation Research (SBIR) program. One result of this research was the High Efficiency Lighting with Integrated Adaptive Control (HELIAC) system, components of which have been incorporated into a variety of agricultural greenhouse and consumer aquarium lighting features. The new lighting systems can be adapted to a specific plant species during a specific growth stage, allowing maximum efficiency in light absorption by all available photosynthetic tissues.

  6. Plant growth chamber M design

    NASA Technical Reports Server (NTRS)

    Prince, R. P.; Knott, W. M.

    1986-01-01

    Crop production is just one of the many processes involved in establishing long term survival of man in space. The benefits of integrating higher plants into the overall plan was recognized early by NASA through the Closed Ecological Life Support System (CELSS) program. The first step is to design, construct, and operate a sealed (gas, liquid, and solid) plant growth chamber. A 3.6 m diameter by 6.7 m high closed cylinder (previously used as a hypobaric vessel during the Mercury program) is being modified for this purpose. The chamber is mounted on legs with the central axis vertical. Entrance to the chamber is through an airlock. This chamber will be devoted entirely to higher plant experimentation. Any waste treatment, food processing or product storage studies will be carried on outside of this chamber. Its primary purpose is to provide input and output data on solids, liquids, and gases for single crop species and multiple species production using different nutrient delivery systems.

  7. Lactam inhibiting Streptococcus mutans growth on titanium.

    PubMed

    Xavier, J G; Geremias, T C; Montero, J F D; Vahey, B R; Benfatti, C A M; Souza, J C M; Magini, R S; Pimenta, A L

    2016-11-01

    The aim of this work was to analyze the activity of novel synthetic lactams on preventing biofilm formation on titanium surfaces. Titanium (Ti6Al4V) samples were exposed to Streptococcus mutans cultures in the presence or absence of a synthetic lactam. After 48h incubation, planktonic growth was determined by spectrophotometry. Biofilm was evaluated by crystal violet staining and colony forming units (CFU·ml(-)(1)), followed by scanning electron microscopy (SEM). Results showed that the average of adhered viable cells was approximately 1.5×10(2)CFU/ml in the presence of lactam and 4×10(2)CFU/ml in its absence. This novel compound was considerable active in reducing biofilm formation over titanium surfaces, indicating its potential for the development of antimicrobial drugs targeting the inhibition of the initial stages of bacterial biofilms on dental implants abutments. PMID:27524086

  8. Peniamidienone and penidilamine, plant growth regulators produced by the fungus Penicillium sp. No. 13.

    PubMed

    Kimura, Y; Mizuno, T; Kawano, T; Okada, K; Shimada, A

    2000-04-01

    Peniamidienone and penidilamine were isolated from cultures of the fungus Penicillium sp. No. 13 as new plant growth regulators and their structures were established by NMR spectroscopic studies. Peniamidienone showed weak inhibition of lettuce seedling growth.

  9. Complementarity among plant growth promoting traits in rhizospheric bacterial communities promotes plant growth.

    PubMed

    Singh, Mangal; Awasthi, Ashutosh; Soni, Sumit K; Singh, Rakshapal; Verma, Rajesh K; Kalra, Alok

    2015-10-27

    An assessment of roles of rhizospheric microbial diversity in plant growth is helpful in understanding plant-microbe interactions. Using random combinations of rhizospheric bacterial species at different richness levels, we analysed the contribution of species richness, compositions, interactions and identity on soil microbial respiration and plant biomass. We showed that bacterial inoculation in plant rhizosphere enhanced microbial respiration and plant biomass with complementary relationships among bacterial species. Plant growth was found to increase linearly with inoculation of rhizospheric bacterial communities with increasing levels of species or plant growth promoting trait diversity. However, inoculation of diverse bacterial communities having single plant growth promoting trait, i.e., nitrogen fixation could not enhance plant growth over inoculation of single bacteria. Our results indicate that bacterial diversity in rhizosphere affect ecosystem functioning through complementary relationship among plant growth promoting traits and may play significant roles in delivering microbial services to plants.

  10. Complementarity among plant growth promoting traits in rhizospheric bacterial communities promotes plant growth

    PubMed Central

    Singh, Mangal; Awasthi, Ashutosh; Soni, Sumit K.; Singh, Rakshapal; Verma, Rajesh K.; Kalra, Alok

    2015-01-01

    An assessment of roles of rhizospheric microbial diversity in plant growth is helpful in understanding plant-microbe interactions. Using random combinations of rhizospheric bacterial species at different richness levels, we analysed the contribution of species richness, compositions, interactions and identity on soil microbial respiration and plant biomass. We showed that bacterial inoculation in plant rhizosphere enhanced microbial respiration and plant biomass with complementary relationships among bacterial species. Plant growth was found to increase linearly with inoculation of rhizospheric bacterial communities with increasing levels of species or plant growth promoting trait diversity. However, inoculation of diverse bacterial communities having single plant growth promoting trait, i.e., nitrogen fixation could not enhance plant growth over inoculation of single bacteria. Our results indicate that bacterial diversity in rhizosphere affect ecosystem functioning through complementary relationship among plant growth promoting traits and may play significant roles in delivering microbial services to plants. PMID:26503744

  11. Decorin: A Growth Factor Antagonist for Tumor Growth Inhibition

    PubMed Central

    Järvinen, Tero A. H.; Prince, Stuart

    2015-01-01

    Decorin (DCN) is the best characterized member of the extracellular small leucine-rich proteoglycan family present in connective tissues, typically in association with or “decorating” collagen fibrils. It has substantial interest to clinical medicine owing to its antifibrotic, anti-inflammatory, and anticancer effects. Studies on DCN knockout mice have established that a lack of DCN is permissive for tumor development and it is regarded as a tumor suppressor gene. A reduced expression or a total disappearance of DCN has been reported to take place in various forms of human cancers during tumor progression. Furthermore, when used as a therapeutic molecule, DCN has been shown to inhibit tumor progression and metastases in experimental cancer models. DCN affects the biology of various types of cancer by targeting a number of crucial signaling molecules involved in cell growth, survival, metastasis, and angiogenesis. The active sites for the neutralization of different growth factors all reside in different parts of the DCN molecule. An emerging concept that multiple proteases, especially those produced by inflammatory cells, are capable of cleaving DCN suggests that native DCN could be inactivated in a number of pathological inflammatory conditions. In this paper, we review the role of DCN in cancer. PMID:26697491

  12. Cinnamic acid increases lignin production and inhibits soybean root growth.

    PubMed

    Salvador, Victor Hugo; Lima, Rogério Barbosa; dos Santos, Wanderley Dantas; Soares, Anderson Ricardo; Böhm, Paulo Alfredo Feitoza; Marchiosi, Rogério; Ferrarese, Maria de Lourdes Lucio; Ferrarese-Filho, Osvaldo

    2013-01-01

    Cinnamic acid is a known allelochemical that affects seed germination and plant root growth and therefore influences several metabolic processes. In the present work, we evaluated its effects on growth, indole-3-acetic acid (IAA) oxidase and cinnamate 4-hydroxylase (C4H) activities and lignin monomer composition in soybean (Glycine max) roots. The results revealed that exogenously applied cinnamic acid inhibited root growth and increased IAA oxidase and C4H activities. The allelochemical increased the total lignin content, thus altering the sum and ratios of the p-hydroxyphenyl (H), guaiacyl (G), and syringyl (S) lignin monomers. When applied alone or with cinnamic acid, piperonylic acid (PIP, a quasi-irreversible inhibitor of C4H) reduced C4H activity, lignin and the H, G, S monomer content compared to the cinnamic acid treatment. Taken together, these results indicate that exogenously applied cinnamic acid can be channeled into the phenylpropanoid pathway via the C4H reaction, resulting in an increase in H lignin. In conjunction with enhanced IAA oxidase activity, these metabolic responses lead to the stiffening of the cell wall and are followed by a reduction in soybean root growth.

  13. Cinnamic acid increases lignin production and inhibits soybean root growth.

    PubMed

    Salvador, Victor Hugo; Lima, Rogério Barbosa; dos Santos, Wanderley Dantas; Soares, Anderson Ricardo; Böhm, Paulo Alfredo Feitoza; Marchiosi, Rogério; Ferrarese, Maria de Lourdes Lucio; Ferrarese-Filho, Osvaldo

    2013-01-01

    Cinnamic acid is a known allelochemical that affects seed germination and plant root growth and therefore influences several metabolic processes. In the present work, we evaluated its effects on growth, indole-3-acetic acid (IAA) oxidase and cinnamate 4-hydroxylase (C4H) activities and lignin monomer composition in soybean (Glycine max) roots. The results revealed that exogenously applied cinnamic acid inhibited root growth and increased IAA oxidase and C4H activities. The allelochemical increased the total lignin content, thus altering the sum and ratios of the p-hydroxyphenyl (H), guaiacyl (G), and syringyl (S) lignin monomers. When applied alone or with cinnamic acid, piperonylic acid (PIP, a quasi-irreversible inhibitor of C4H) reduced C4H activity, lignin and the H, G, S monomer content compared to the cinnamic acid treatment. Taken together, these results indicate that exogenously applied cinnamic acid can be channeled into the phenylpropanoid pathway via the C4H reaction, resulting in an increase in H lignin. In conjunction with enhanced IAA oxidase activity, these metabolic responses lead to the stiffening of the cell wall and are followed by a reduction in soybean root growth. PMID:23922685

  14. Spiral Growth in Plants: Models and Simulations

    ERIC Educational Resources Information Center

    Allen, Bradford D.

    2004-01-01

    The analysis and simulation of spiral growth in plants integrates algebra and trigonometry in a botanical setting. When the ideas presented here are used in a mathematics classroom/computer lab, students can better understand how basic assumptions about plant growth lead to the golden ratio and how the use of circular functions leads to accurate…

  15. Transcriptomic evaluation of plant growth inhibitory activity of goniothalamin from the Malaysian medicinal plant Goniothalamus andersonii.

    PubMed

    Wasano, Naoya; Takemura, Tomoko; Ismil, Raihan; Bakar, Baki; Fujii, Yoshiharu

    2015-05-01

    Goniothalamin produced by the Malaysian medicinal plant, Goniothalamus andersonii J. Sinclair, strongly inhibits plant growth. However, its mode of action has not been characterized at the gene expression level. We conducted DNA microarray assay to analyze the changes in early gene responses of Arabidopsis thaliana seedlings. After a 6-h exposure to goniothalamin, we observed an upregulation of genes highly associated with heat response, and 22 heat shock protein (AtHSP) genes were upregulated more than 50 fold. Together with these genes, we observed upregulation of the genes related to oxidative stress and protein folding. Also, the genes related to cell wall modification and cell growth, expansin (AtEXPA) genes, were significantly downregulated. The results suggested that goniothalamin induces oxidative stresses and inhibits the expression of cell wall-associated proteins resulting in growth inhibition of Arabidopsis seedlings. PMID:26058144

  16. Sanguinarine suppresses prostate tumor growth and inhibits survivin expression.

    PubMed

    Sun, Meng; Lou, Wei; Chun, Jae Yeon; Cho, Daniel S; Nadiminty, Nagalakshmi; Evans, Christopher P; Chen, Jun; Yue, Jiao; Zhou, Qinghua; Gao, Allen C

    2010-03-01

    Prostate cancer is a frequently occurring disease and is the second leading cause of cancer-related deaths of men in the United States. Current treatments have proved inadequate in curing or controlling prostate cancer, and a search for agents for the management of this disease is urgently needed. Survivin plays an important role in both progression of castration-resistant prostate cancer and resistance to chemotherapy. Altered expression of survivin in prostate cancer cells is associated with cancer progression, drug/radiation resistance, poor prognosis, and short patient survival. In the present study, the authors performed a cell-based rapid screen of the Prestwick Chemical Library consisting of 1120 Food and Drug Administration-approved compounds with known safety and bioavailability in humans to identify potential inhibitors of survivin and anticancer agents for prostate cancer. Sanguinarine, a benzophenanthridine alkaloid derived primarily from the bloodroot plant, was identified as a novel inhibitor of survivin that selectively kills prostate cancer cells over "normal" prostate epithelial cells. The authors found that sanguinarine inhibits survivin protein expression through protein degradation via the ubiquitin-proteasome system. Sanguinarine induces apoptosis and inhibits growth of human prostate cancer cells and in vivo tumor formation. Administration of sanguinarine, beginning 3 days after ectopic implantation of DU145 human prostate cancer cells, reduces both tumor weight and volume. In addition, sanguinarine sensitized paclitaxel-mediated growth inhibition and apoptosis, offering a potential therapeutic strategy for overcoming taxol resistance. These results suggest that sanguinarine may be developed as an agent either alone or in combination with taxol for treatment of prostate cancer overexpressing survivin. PMID:21318089

  17. SPATULA links daytime temperature and plant growth rate.

    PubMed

    Sidaway-Lee, Kate; Josse, Eve-Marie; Brown, Alanna; Gan, Yinbo; Halliday, Karen J; Graham, Ian A; Penfield, Steven

    2010-08-24

    Plants exhibit a wide variety of growth rates that are known to be determined by genetic and environmental factors, and different plants grow optimally at different temperatures, indicating that this is a genetically determined character. Moderate decreases in ambient temperature inhibit vegetative growth, but the mechanism is poorly understood, although a decrease in gibberellin (GA) levels is known to be required. Here we demonstrate that the basic helix-loop-helix transcription factor SPATULA (SPT), previously known to be a regulator of low temperature-responsive germination, mediates the repression of growth by cool daytime temperatures but has little or no growth-regulating role under warmer conditions. We show that only daytime temperatures affect vegetative growth and that SPT couples morning temperature to growth rate. In seedlings, warm temperatures inhibit the accumulation of the SPT protein, and SPT autoregulates its own transcript abundance in conjunction with diurnal effects. Genetic data show that repression of growth by SPT is independent of GA signaling and phytochrome B, as previously shown for PIF4. Our data suggest that SPT integrates time of day and temperature signaling to control vegetative growth rate.

  18. Plant photomorphogenesis and canopy growth

    NASA Technical Reports Server (NTRS)

    Ballare, Carlos L.; Scopel, Ana L.

    1994-01-01

    An important motivation for studying photomorphogenesis is to understand the relationships among plant photophysiology in canopies, canopy productivity, and agronomic yield. This understanding is essential to optimize lighting systems used for plant farming in controlled environments (CE) and for the design of genetically engineered crop strains with altered photoresponses. This article provides an overview of some basic principles of plant photomorphogenesis in canopies and discusses their implications for (1) scaling up information on plant photophysiology from individual plants in CE to whole canopies in the field, and (2) designing lighting conditions to increase plant productivity in CE used for agronomic purposes (e.g. space farming in CE Life Support Systems). We concentrate on the visible (lambda between 400 and 700 nm) and far-infrared (FR; lambda greater than 700 nm) spectral regions, since the ultraviolet (UV; 280 to 400 nm) is covered by other authors in this volume.

  19. Results of a screening programme to identify plants or plant extracts that inhibit ruminal protein degradation.

    PubMed

    Selje, N; Hoffmann, E M; Muetzel, S; Ningrat, R; Wallace, R J; Becker, K

    2007-07-01

    One aim of the EC Framework V project, 'Rumen-up' (QLK5-CT-2001-00 992), was to find plants or plant extracts that would inhibit the nutritionally wasteful degradation of protein in the rumen. A total of 500 samples were screened in vitro using 14C-labelled casein in a 30-min incubation with ruminal digesta. Eight were selected for further investigation using a batch fermentation system and soya protein and bovine serum albumin as proteolysis substrates; proteolysis was monitored over 12 h by the disappearance of soluble protein and the production of branched SCFA and NH3. Freeze-dried, ground foliage of Peltiphyllum peltatum, Helianthemum canum, Arbutus unedo, Arctostaphylos uva-ursi and Knautia arvensis inhibited proteolysis (P < 0.05), while Daucus carota, Clematis vitalba and Erica arborea had little effect. Inhibition by the first four samples appeared to be caused by the formation of insoluble tannin-protein complexes. The samples were rich in phenolics and inhibition was reversed by polyethyleneglycol. In contrast, K. arvensis contained low concentrations of phenolics and no tannins, had no effect in the 30-min assay, yet inhibited the degradation rate of soluble protein (by 14 %, P < 0.0001) and the production of branched SCFA (by 17 %, P < 0.05) without precipitating protein in the 12-h batch fermentation. The effects showed some resemblance to those obtained in parallel incubations containing 3 mum-monensin, suggesting that K. arvensis may be a plant-derived feed additive that can suppress growth and activity of key proteolytic ruminal micro-organisms in a manner similar to that already well known for monensin. PMID:17445338

  20. Trickle water and feeding system in plant culture and light-dark cycle effects on plant growth

    NASA Technical Reports Server (NTRS)

    Takano, T.; Inada, K.; Takanashi, J.

    1987-01-01

    Rockwool, as an inert medium covered or bagged with polyethylene film, can be effectively used for plant culture in space stations. The most important machine is the pump adjusting the dripping rate in the feeding system. Hydro-aeroponics may be adaptable to a space laboratory. The shortening of the light-dark cycles inhibits plant growth and induces an abnormal morphogenesis. A photoperiod of 12 hr dark may be needed for plant growth.

  1. Trickle water and feeding system in plant culture and light-dark cycle effects on plant growth

    NASA Astrophysics Data System (ADS)

    Takano, T.; Inada, K.; Takanashi, J.

    Rockwool, as an inert medium covered or bagged with polyethylene film, can be effectively used for plant culture in space station. The most important machine is the pump adjusting the dripping rate in the feeding system. Hydro-aeroponics may be adaptable to a space laboratory. The shortening of the light-dark cycles inhibits plant growth and induces an abnormal morphogenesis. A photoperiod of 12-hr-dark may be needed for plant growth.

  2. Trickle water and feeding system in plant culture and light-dark cycle effects on plant growth.

    PubMed

    Takano, T; Inada, K; Takanashi, J

    1987-01-01

    Rockwool, as an inert medium covered or bagged with polyethylene film, can be effectively used for plant culture in space station. The most important machine is the pump adjusting the dripping rate in the feeding system. Hydro-aeroponics may be adaptable to a space laboratory. The shortening of the light-dark cycles inhibits plant growth and induces an abnormal morphogenesis. A photoperiod of 12-hr-dark may be needed for plant growth. PMID:11537264

  3. Calcite crystal growth rate inhibition by polycarboxylic acids

    USGS Publications Warehouse

    Reddy, M.M.; Hoch, A.R.

    2001-01-01

    Calcite crystal growth rates measured in the presence of several polycarboxyclic acids show that tetrahydrofurantetracarboxylic acid (THFTCA) and cyclopentanetetracarboxylic acid (CPTCA) are effective growth rate inhibitors at low solution concentrations (0.01 to 1 mg/L). In contrast, linear polycarbocylic acids (citric acid and tricarballylic acid) had no inhibiting effect on calcite growth rates at concentrations up to 10 mg/L. Calcite crystal growth rate inhibition by cyclic polycarboxyclic acids appears to involve blockage of crystal growth sites on the mineral surface by several carboxylate groups. Growth morphology varied for growth in the absence and in the presence of both THFTCA and CPTCA. More effective growth rate reduction by CPTCA relative to THFTCA suggests that inhibitor carboxylate stereochemical orientation controls calcite surface interaction with carboxylate inhibitors. ?? 20O1 Academic Press.

  4. How Plants Make Light Work of Growth.

    ERIC Educational Resources Information Center

    Kendrick, R. E.

    1981-01-01

    Presented is one of a series of articles designed to help science teachers keep current on ideas in specific areas in biology. Contained is information on how plants use light for growth, seed germination, and flowering. (PB)

  5. Sealed Plant-Growth Chamber For Clinostat

    NASA Technical Reports Server (NTRS)

    Brown, Christopher S.; Dreschel, Thomas W.

    1993-01-01

    Laboratory chamber for growing plants used to measure photosynthesis and respiration in simulated microgravity. Holds plant specimens while rotated on clinostat, see article, "Clinostat Delivers Power To Plant-Growth Cabinets" (KSC-11537). Provides way of comparing gas-exchange rates of plants rotated horizontally on clinostat with those of stationary or vertically rotated plants. Gas extracted for analysis without stopping clinostat. Chamber includes potlike base and cylindrical cover, both made of transparent acrylic pipe. Gasket forms seal between cover and bottom plate of base. Cover bolted to pot baseplate, which in turn bolted to clinostat.

  6. Rotary plant growth accelerating apparatus. [weightlessness

    NASA Technical Reports Server (NTRS)

    Dedolph, R. D. (Inventor)

    1975-01-01

    Rotary plant growth accelerating apparatus for increasing plant yields by effectively removing the growing plants from the constraints of gravity and increasing the plant yield per unit of space is described. The apparatus is comprised of cylindrical plant beds supported radially removed from a primary axis of rotation, with each plant bed being driven about its own secondary axis of rotation and simultaneously moved in a planetary path about the primary axis of rotation. Each plant bed is formed by an apertured outer cylinder, a perforated inner cylinder positioned coaxially, and rooting media disposed in the space between. A rotatable manifold distributes liquid nutrients and water to the rooting media through the perforations in the inner cylinders as the plant beds are continuously rotated by suitable drive means.

  7. Effect of microgravity on plant growth

    NASA Technical Reports Server (NTRS)

    Lewis, Norman G.

    1994-01-01

    The overall goal of this research is to determine the effect of microgravity proper on plant growth (metabolism and cell wall formation). In addressing this goal, the work conducted during this grant period was divided into three components: analyses of various plant tissues previously grown in space aboard MIR Space Station; analyses of wheat tissues grown on Shuttle flight STS-51; and Phenylpropanoid metabolism and plant cell wall synthesis (earth-based investigations).

  8. Plant Growth Module (PGM) conceptual design

    NASA Technical Reports Server (NTRS)

    Schwartzkopf, Steven H.; Rasmussen, Daryl

    1987-01-01

    The Plant Growth Module for the Controlled Ecological Life Support System (CELSS), designed to answer basic science questions related to growing plants in closed systems, is described functionally with artist's conception drawings. Subsystems are also described, including enclosure and access; data acquisition and control; gas monitor and control; heating, ventilation, and air conditioning; air delivery; nutrient monitor and control; microbial monitoring and control; plant support and nutrient delivery; illumination; and internal operations. The hardware development plan is outlined.

  9. Carbohydrate Level and Growth of Tomato Plants

    PubMed Central

    Gent, Martin P. N.

    1984-01-01

    To what extent can the influence of environment on greenhouse tomato plants (Lycopersicon esculentum L.) be explained by a linear response of the growth rate to carbohydrate level? To answer this question, young tomato plants were transplanted in January and March and grown for one-month periods under natural light either with or without CO2 enrichment to 1000 microliters per liter and either under a constant minimum temperature of 15°C or a minimum temperature that fluctuated between 20°C for 12 hours including the photoperiod and 10°C for the remaining 12 hours. The carbohydrate levels were measured for plants under all growth conditions at several times in the diurnal cycle. At the average irradiance in January, 2.3 megajoules per square meter per day, plants under CO2 enrichment grew 15% faster and had, on average, total nonstructural carbohydrate levels 27 milligrams per gram greater and soluble carbohydrates 3 milligrams per gram greater at all hours of the day than did plants grown under ambient CO2. Plants grown under fluctuating diurnal temperature grew slightly faster and had total nonstructural carbohydrate levels on average 8 milligrams per gram greater than plants grown under a more constant temperature. At the average irradiance in March-April, 4.3 megajoules per square meter per day, growth and carbohydrate level increased with CO2 enrichment under the control temperature regime but not under fluctuating temperatures. Plants in all growth regimens grew faster than in January. Over all plantings and growth regimens, relative growth rates were more highly correlated to total nonstructural carbohydrate levels than they were to irradiance, CO2, or temperature. PMID:16663908

  10. Endocannabinoids inhibit the growth of free-living amoebae.

    PubMed

    Dey, Rafik; Pernin, Pierre; Bodennec, Jacques

    2010-07-01

    The cannabinoid Delta(9)-tetrahydrocannabinol inhibits the growth of some pathogenic amoebae in vitro and exacerbates amoebic encephalitis in animal models. However, the effects of endogenous cannabinoids on amoebae remain unknown. Therefore, we tested several endocannabinoids (N-acyl ethanolamines and 2-O-acyl glycerol) on different genera of amoebae. The results showed that all of the endocannabinoids tested inhibit amoebic growth at subpharmacological doses, with 50% inhibitory concentrations ranging from 15 to 20 microM. A nonhydrolyzable endocannabinoid had similar effects, showing that the inhibition seen results from endocannabinoids per se rather than from a catabolic product.

  11. Endocannabinoids Inhibit the Growth of Free-Living Amoebae▿

    PubMed Central

    Dey, Rafik; Pernin, Pierre; Bodennec, Jacques

    2010-01-01

    The cannabinoid Δ9-tetrahydrocannabinol inhibits the growth of some pathogenic amoebae in vitro and exacerbates amoebic encephalitis in animal models. However, the effects of endogenous cannabinoids on amoebae remain unknown. Therefore, we tested several endocannabinoids (N-acyl ethanolamines and 2-O-acyl glycerol) on different genera of amoebae. The results showed that all of the endocannabinoids tested inhibit amoebic growth at subpharmacological doses, with 50% inhibitory concentrations ranging from 15 to 20 μM. A nonhydrolyzable endocannabinoid had similar effects, showing that the inhibition seen results from endocannabinoids per se rather than from a catabolic product. PMID:20479202

  12. Microgravity Effects on Plant Growth and Lignification

    NASA Astrophysics Data System (ADS)

    Cowles, Joe R.; Lemay, Richard; Jahns, Gary

    1988-12-01

    Lignin is a major cellular component of higher plants. One function of lignin is to support vertical plant growth in a gravity environment. Various investigators working in the 1 g environment have concluded that lignification is influenced by gravity. An experiment was designed for flight on Spacelab II to determine the effect of microgravity on lignification in young plant seedlings. A secondary objective of the experiment was to examine the effect of microgravity on overall seedling growth. Mung bean and oat seeds germinated and the seedlings grew during the Spacelab II mission. Growth of flight mung bean and oat seedlings, however, was slower, and the seedlings exhibited stem and root orientation difficulties. Flight pine seedlings were similar in appearance and growth to 1 g controls. The rate of lignin formation in seedlings grown in space was significantly less in all three species in comparison to 1 g controls. The experiment provided direct evidence that lignification is slowed in a microgravity environment.

  13. SELECTIVE REVERSIBLE INHIBITION OF MICROBIAL GROWTH WITH PYRITHIAMINE

    PubMed Central

    Woolley, D. W.; White, A. G. C.

    1943-01-01

    Growth of many microbial species was inhibited by pyrithiamine, the pyridine analog of thiamine. Growth of many other species was not influenced. In a series of bacteria, yeasts, and molds, it was found that inhibition of growth occurred only in those in which growth was stimulated by thiamine or its component pyrimidine and thiazole portions. The amount of pyrithiamine required for inhibition was correlated with the type of thiamine requirements of various species. The least amount was needed to inhibit organisms which required intact thiamine. Those which could use the pyrimidine and thiazole portions were not so readily inhibited. In the case of the former organisms, half maximal inhibition was produced by as little as 0.03 γ per cc. In all instances, the inhibition was overcome by sufficient amounts of thiamine. The synthesis of thiamine by insusceptible species was studied, and it was concluded that formation of thiamine or other antagonistic substance did not provide an adequate explanation of the resistance of these species to the action of pyrithiamine. PMID:19871344

  14. Timing of growth inhibition following shoot inversion in Pharbitis nil

    NASA Technical Reports Server (NTRS)

    Abdel-Rahman, A. M.; Cline, M. G.

    1989-01-01

    Shoot inversion in Pharbitis nil results in the enhancement of ethylene production and in the inhibition of elongation in the growth zone of the inverted shoot. The initial increase in ethylene production previously was detected within 2 to 2.75 hours after inversion. In the present study, the initial inhibition of shoot elongation was detected within 1.5 to 4 hours with a weighted mean of 2.4 hours. Ethylene treatment of upright shoots inhibited elongation in 1.5 hours. A cause and effect relationship between shoot inversion-enhanced ethylene production and inhibition of elongation cannot be excluded.

  15. Plant growth-promoting rhizobacteria (PGPR): emergence in agriculture.

    PubMed

    Bhattacharyya, P N; Jha, D K

    2012-04-01

    Plant growth-promoting rhizobacteria (PGPR) are the rhizosphere bacteria that can enhance plant growth by a wide variety of mechanisms like phosphate solubilization, siderophore production, biological nitrogen fixation, rhizosphere engineering, production of 1-Aminocyclopropane-1-carboxylate deaminase (ACC), quorum sensing (QS) signal interference and inhibition of biofilm formation, phytohormone production, exhibiting antifungal activity, production of volatile organic compounds (VOCs), induction of systemic resistance, promoting beneficial plant-microbe symbioses, interference with pathogen toxin production etc. The potentiality of PGPR in agriculture is steadily increased as it offers an attractive way to replace the use of chemical fertilizers, pesticides and other supplements. Growth promoting substances are likely to be produced in large quantities by these rhizosphere microorganisms that influence indirectly on the overall morphology of the plants. Recent progress in our understanding on the diversity of PGPR in the rhizosphere along with their colonization ability and mechanism of action should facilitate their application as a reliable component in the management of sustainable agricultural system. The progress to date in using the rhizosphere bacteria in a variety of applications related to agricultural improvement along with their mechanism of action with special reference to plant growth-promoting traits are summarized and discussed in this review.

  16. Transgenic plants with enhanced growth characteristics

    DOEpatents

    Unkefer, Pat J.; Anderson, Penelope S.; Knight, Thomas J.

    2016-09-06

    The invention relates to transgenic plants exhibiting dramatically enhanced growth rates, greater seed and fruit/pod yields, earlier and more productive flowering, more efficient nitrogen utilization, increased tolerance to high salt conditions, and increased biomass yields. In one embodiment, transgenic plants engineered to over-express both glutamine phenylpyruvate transaminase (GPT) and glutamine synthetase (GS) are provided. The GPT+GS double-transgenic plants of the invention consistently exhibit enhanced growth characteristics, with T0 generation lines showing an increase in biomass over wild type counterparts of between 50% and 300%. Generations that result from sexual crosses and/or selfing typically perform even better, with some of the double-transgenic plants achieving an astounding four-fold biomass increase over wild type plants.

  17. Inhibition of rate of tumor growth by creatine and cyclocreatine.

    PubMed Central

    Miller, E E; Evans, A E; Cohn, M

    1993-01-01

    Growth rate inhibition of subcutaneously implanted tumors results from feeding rats and athymic nude mice diets containing 1% cyclocreatine or 1%, 2%, 5%, or 10% creatine. The tumors studied included rat mammary tumors (Ac33tc in Lewis female rats and 13762A in Fischer 344 female rats), rat sarcoma MCI in Lewis male rats, and tumors resulting from the injection of two human neuroblastoma cell lines, IMR-5 and CHP-134, in athymic nude mice. Inhibition was observed regardless of the time experimental diets were administered, either at the time of tumor implantation or after the appearance of palpable tumors. For mammary tumor Ac33tc, the growth inhibition during 24 days after the implantation was approximately 50% for both 1% cyclocreatine and 1% creatine, and inhibition increased as creatine was increased from 2% to 10% of the diet. For the other rat mammary tumor (13762A), there was approximately 35% inhibition by both 1% cyclocreatine and 2% creatine. In the case of the MCI sarcoma, the inhibitory effect appeared more pronounced at earlier periods of growth, ranging from 26% to 41% for 1% cyclocreatine and from 30% to 53% for 1% creatine; there was no significant difference in growth rate between the tumors in the rats fed 1% and 5% creatine. The growth rate of tumors in athymic nude mice, produced by implantation of the human neuroblastoma IMR-5 cell line, appeared somewhat more effectively inhibited by 1% cyclocreatine than by 1% creatine, and 5% creatine feeding was most effective. For the CHP-134 cell line, 33% inhibition was observed for the 1% cyclocreatine diet and 71% for the 5% creatine diet. In several experiments, a delay in appearance of tumors was observed in animals on the experimental diets. In occasional experiments, neither additive inhibited tumor growth rate for the rat tumors or the athymic mouse tumors. Images Fig. 3 PMID:8475072

  18. Plant Growth Modelling and Applications: The Increasing Importance of Plant Architecture in Growth Models

    PubMed Central

    Fourcaud, Thierry; Zhang, Xiaopeng; Stokes, Alexia; Lambers, Hans; Körner, Christian

    2008-01-01

    Background Modelling plant growth allows us to test hypotheses and carry out virtual experiments concerning plant growth processes that could otherwise take years in field conditions. The visualization of growth simulations allows us to see directly and vividly the outcome of a given model and provides us with an instructive tool useful for agronomists and foresters, as well as for teaching. Functional–structural (FS) plant growth models are nowadays particularly important for integrating biological processes with environmental conditions in 3-D virtual plants, and provide the basis for more advanced research in plant sciences. Scope In this viewpoint paper, we ask the following questions. Are we modelling the correct processes that drive plant growth, and is growth driven mostly by sink or source activity? In current models, is the importance of soil resources (nutrients, water, temperature and their interaction with meristematic activity) considered adequately? Do classic models account for architectural adjustment as well as integrating the fundamental principles of development? Whilst answering these questions with the available data in the literature, we put forward the opinion that plant architecture and sink activity must be pushed to the centre of plant growth models. In natural conditions, sinks will more often drive growth than source activity, because sink activity is often controlled by finite soil resources or developmental constraints. PMA06 This viewpoint paper also serves as an introduction to this Special Issue devoted to plant growth modelling, which includes new research covering areas stretching from cell growth to biomechanics. All papers were presented at the Second International Symposium on Plant Growth Modeling, Simulation, Visualization and Applications (PMA06), held in Beijing, China, from 13–17 November, 2006. Although a large number of papers are devoted to FS models of agricultural and forest crop species, physiological and genetic

  19. Inhibition of Plant Asparagine Synthetase by Monoterpene Cineoles1

    PubMed Central

    Romagni, Joanne G.; Duke, Stephen O.; Dayan, Franck E.

    2000-01-01

    Asparagine (Asn) synthetase (AS) is the key enzyme in Asn biosynthesis and plays an important role in nitrogen mobilization. Despite its important physiological function, little research has been done documenting inhibitors of plant AS. Plant growth inhibition caused by the natural monoterpene 1,4-cineole and its structurally related herbicide cinmethylin was reversed 65% and 55%, respectively, by providing 100 μm Asn exogenously. Reversion of the phytotoxic effect was dependent on the concentration of Asn. The presence of either 1,4-cineole or cinmethylin stimulated root uptake of [14C]Asn by lettuce (Lactuca sativa) seedlings. Although the physiological responses suggested that both compounds affected Asn biosynthesis, biochemical analysis of AS activity showed that the natural monoterpene was a potent inhibitor (I50 = approximately 0.5 μm) of the enzyme, whereas the commercial product was not inhibitory up to levels of 10 mm. Analysis of the putative metabolite, 2-hydroxy-1,4-cineole, showed that the cis-enantiomer was much more active than the trans-enantiomer, suggesting that the hydroxyl group was involved in the specific ligand/active site interaction. This is the first report that AS is a suitable herbicide target site, and that cinmethylin is apparently a proherbicide that requires metabolic bioactivation via cleavage of the benzyl-ether side chain. PMID:10859202

  20. Regulation of Plant Morphology by Growth Retardants

    PubMed Central

    Grossmann, Klaus; Kwiatkowski, Jacek; Siebecker, Heinrich; Jung, Johannes

    1987-01-01

    The effects of the growth retardants tetcyclacis, a norbornenodiazetine, and LAB 150 978, a dioxanylalkenyl triazole, on seedling growth and endogenous levels of phytohormone-like substances in Glycine max L. cv Maple Arrow were studied. The levels of phytohormone-like substances in the root and in the various shoot tissues were analyzed by immunoassay. After seed treatment with both compounds, shoot growth was reduced more intensively than root growth. Both compounds decreased, on a fresh weight basis, the amount of various immunoreactive gibberellins when compared with the levels in control plants, especially in the shoot tip. Likewise, the growth retardants lowered the levels of abscisic acid-like material, particularly in the primary leaf, the epicotyl and the root. In contrast, the levels of trans-zeatin-riboside and dihydrozeatin-riboside-type cytokinins were considerably elevated by the growth retardants, mainly in the primary leaf, epicotyl, and hypocotyl. On the other hand the level of isopentenyladenosine-like material was less influenced. In general, the immunoreactive 3-indoleacetic acid content in the different plant parts was changed only slightly. It is assumed that besides their effect on gibberellin content both compounds interfere directly or indirectly with the regulation of the endogenous levels of abscisic acid and cytokinins. This might be seen as an additional mode of action of growth retardants explaining some side effects on developmental processes of treated plants, e.g. delayed senescence and enhanced chlorophyll concentration in the leaves. PMID:16665554

  1. Stochasticity in plant cellular growth and patterning

    PubMed Central

    Meyer, Heather M.; Roeder, Adrienne H. K.

    2014-01-01

    Plants, along with other multicellular organisms, have evolved specialized regulatory mechanisms to achieve proper tissue growth and morphogenesis. During development, growing tissues generate specialized cell types and complex patterns necessary for establishing the function of the organ. Tissue growth is a tightly regulated process that yields highly reproducible outcomes. Nevertheless, the underlying cellular and molecular behaviors are often stochastic. Thus, how does stochasticity, together with strict genetic regulation, give rise to reproducible tissue development? This review draws examples from plants as well as other systems to explore stochasticity in plant cell division, growth, and patterning. We conclude that stochasticity is often needed to create small differences between identical cells, which are amplified and stabilized by genetic and mechanical feedback loops to begin cell differentiation. These first few differentiating cells initiate traditional patterning mechanisms to ensure regular development. PMID:25250034

  2. The rhizobacterium Arthrobacter agilis produces dimethylhexadecylamine, a compound that inhibits growth of phytopathogenic fungi in vitro.

    PubMed

    Velázquez-Becerra, Crisanto; Macías-Rodríguez, Lourdes I; López-Bucio, José; Flores-Cortez, Idolina; Santoyo, Gustavo; Hernández-Soberano, Christian; Valencia-Cantero, Eduardo

    2013-12-01

    Plant diseases caused by fungal pathogens such as Botrytis cinerea and the oomycete Phytophthora cinnamomi affect agricultural production worldwide. Control of these pests can be done by the use of fungicides such as captan, which may have deleterious effects on human health. This study demonstrates that the rhizobacterium Arthrobacter agilis UMCV2 produces volatile organic compounds that inhibit the growth of B. cinerea in vitro. A single compound from the volatile blends, namely dimethylhexadecylamine (DMHDA), could inhibit the growth of both B. cinerea and P. cinnamomi when supplied to the growth medium in low concentrations. DMHDA also inhibited the growth of beneficial fungi Trichoderma virens and Trichoderma atroviride but at much higher concentrations. DMHDA-related aminolipids containing 4, 8, 10, 12, and 14 carbons in the alkyl chain were tested for their inhibitory effect on the growth of the pathogens. The results show that the most active compound from those tested was dimethyldodecylamine. This effect correlates with a decrease in the number of membrane lipids present in the mycelium of the pathogen including eicosanoic acid, (Z)-9-hexadecenoic acid, methyl ester, and (Z)-9-octadecenoic acid, methyl ester. Strawberry leaflets treated with DMHDA were not injured by the compound. These data indicate that DMHDA and related compounds, which can be produced by microorganisms may effectively inhibit the proliferation of certain plant pathogens. PMID:23674267

  3. Lunar base agriculture: Soils for plant growth

    NASA Technical Reports Server (NTRS)

    Ming, Douglas W. (Editor); Henninger, Donald L. (Editor)

    1989-01-01

    This work provides information on research and experimentation concerning various aspects of food production in space and particularly on the moon. Options for human settlement of the moon and Mars and strategies for a lunar base are discussed. The lunar environment, including the mineralogical and chemical properties of lunar regolith are investigated and chemical and physical considerations for a lunar-derived soil are considered. It is noted that biological considerations for such a soil include controlled-environment crop production, both hydroponic and lunar regolith-based; microorganisms and the growth of higher plants in lunar-derived soils; and the role of microbes to condition lunar regolith for plant cultivation. Current research in the controlled ecological life support system (CELSS) project is presented in detail and future research areas, such as the growth of higher research plants in CELSS are considered. Optimum plant and microbiological considerations for lunar derived soils are examined.

  4. The effect of ultradian and orbital cycles on plant growth

    NASA Technical Reports Server (NTRS)

    Berry, W.; Hoshizaki, T.; Ulrich, A.

    1986-01-01

    In a series of experiments using sugar beets, researchers investigated the effects of varying cycles lengths on growth (0.37 hr to 48 hr). Each cycle was equally divided into a light and dark period so that each treatment regardless of cycle length received the same amount of light over the 17 weeks of the experiment. Two growth parameters were used to evaluate the effects of cycle length, total fresh weight and sucrose content of the storage root. Both parameters showed very similar responses in that under long cycles (12 hr or greater) growth was normal, whereas plants growing under shorter cycle periods were progressively inhibited. Minimum growth occurred at a cycle period of 0.75 hr. The yield at the 0.75 hr cycle, where was at a minimum, for total fresh weight was only 51 percent compared to the 24 hr cycle. The yield of sucrose was even more reduced at 41 percent of the 24 hr cycle.

  5. Trace gases generated in closed plant cultivation systems and their effects on plant growth.

    PubMed

    Tani, A; Kiyota, M; Aiga, I

    1995-12-01

    Interactions between plants and trace gases, especially ethylene, were investigated from two different viewpoints; ethylene is toxic for plant growth, whereas the ethylene release rate of plants can be utilized as a plant growth indicator. When lettuce plants and shiitake mushroom mycelium were cultivated in closed chambers, ethylene concentration increased with time. Ethylene was released both from lettuce plant and from shiitake mushroom mycelium. Dioctyl phthalate (DOP) and Dibutyl phthalate (DBP) were detected, and these concentrations reached 3.7 ngL-1 for DOP and 2.4 ngL-1 for DBP 4 days after closing. Organic solvents such as xylene and toluene and organic siloxane were detected with GCMS. Visible injury was observed in lettuce plants cultivated in the chambers and it seemed to result from trace contaminants such as DOP, DBP, organic solvents, dimethylsiloxane polymer, and ethylene. In order to obtain basic data of ethylene evolution from plants, ethylene concentration in a closed chamber in which the plants were cultivated under a controlled environment (25 degrees C air temperature, 60-70% relative humidity, 250-300 micromoles m-2 s-1 photosynthetic photon flux density (PPFD)) was measured. Lettuce (Lactuca sativa L. cv. Okayama) released ethylene more than Brassica rapa var. pervidis, Brassica campestris var. communis, and Brassica campestris var. narinosa. Ethylene release rate of intact lettuce plant was highly correlated with plant growth parameters such as dry weight, leaf area and photosynthetic rate. Ethylene release rates of intact lettuce plant were affected by cultivation conditions such as ambient CO2 concentration, light intensity and light/dark period. Increase in ambient ethylene level influenced lettuce growth even at the concentration of 0.1 microliter L-1. The level of ethylene inhibited leaf expansion and slightly accelerated chlorophyll degradation. It did not affect photosynthesis and transpiration, and also little affected dry matter

  6. Trace gases generated in closed plant cultivation systems and their effects on plant growth.

    PubMed

    Tani, A; Kiyota, M; Aiga, I

    1995-12-01

    Interactions between plants and trace gases, especially ethylene, were investigated from two different viewpoints; ethylene is toxic for plant growth, whereas the ethylene release rate of plants can be utilized as a plant growth indicator. When lettuce plants and shiitake mushroom mycelium were cultivated in closed chambers, ethylene concentration increased with time. Ethylene was released both from lettuce plant and from shiitake mushroom mycelium. Dioctyl phthalate (DOP) and Dibutyl phthalate (DBP) were detected, and these concentrations reached 3.7 ngL-1 for DOP and 2.4 ngL-1 for DBP 4 days after closing. Organic solvents such as xylene and toluene and organic siloxane were detected with GCMS. Visible injury was observed in lettuce plants cultivated in the chambers and it seemed to result from trace contaminants such as DOP, DBP, organic solvents, dimethylsiloxane polymer, and ethylene. In order to obtain basic data of ethylene evolution from plants, ethylene concentration in a closed chamber in which the plants were cultivated under a controlled environment (25 degrees C air temperature, 60-70% relative humidity, 250-300 micromoles m-2 s-1 photosynthetic photon flux density (PPFD)) was measured. Lettuce (Lactuca sativa L. cv. Okayama) released ethylene more than Brassica rapa var. pervidis, Brassica campestris var. communis, and Brassica campestris var. narinosa. Ethylene release rate of intact lettuce plant was highly correlated with plant growth parameters such as dry weight, leaf area and photosynthetic rate. Ethylene release rates of intact lettuce plant were affected by cultivation conditions such as ambient CO2 concentration, light intensity and light/dark period. Increase in ambient ethylene level influenced lettuce growth even at the concentration of 0.1 microliter L-1. The level of ethylene inhibited leaf expansion and slightly accelerated chlorophyll degradation. It did not affect photosynthesis and transpiration, and also little affected dry matter

  7. Selective chemical binding enhances cesium tolerance in plants through inhibition of cesium uptake.

    PubMed

    Adams, Eri; Chaban, Vitaly; Khandelia, Himanshu; Shin, Ryoung

    2015-03-05

    High concentrations of cesium (Cs(+)) inhibit plant growth but the detailed mechanisms of Cs(+) uptake, transport and response in plants are not well known. In order to identify small molecules with a capacity to enhance plant tolerance to Cs(+), chemical library screening was performed using Arabidopsis. Of 10,000 chemicals tested, five compounds were confirmed as Cs(+) tolerance enhancers. Further investigation and quantum mechanical modelling revealed that one of these compounds reduced Cs(+) concentrations in plants and that the imidazole moiety of this compound bound specifically to Cs(+). Analysis of the analogous compounds indicated that the structure of the identified compound is important for the effect to be conferred. Taken together, Cs(+) tolerance enhancer isolated here renders plants tolerant to Cs(+) by inhibiting Cs(+) entry into roots via specific binding to the ion thus, for instance, providing a basis for phytostabilisation of radiocesium-contaminated farmland.

  8. Developmental Stages in Dynamic Plant Growth Models

    NASA Astrophysics Data System (ADS)

    Maclean, Heather; Dochain, Denis; Waters, Geoff; Stasiak, Michael; Dixon, Mike; Van Der Straeten, Dominique

    2011-09-01

    During the growth of red beet plants in a closed environment plant growth chamber, a change in metabolism was observed (decreasing photosynthetic quotient) which was not predicted by a previously developed simple dynamic model of photosynthesis and respiration reactions. The incorporation of developmental stages into the model allowed for the representation of this change in metabolism without adding unnecessary complexity. Developmental stages were implemented by dividing the model into two successive sub-models with independent yields. The transition between the phases was detected based on online measurements. Results showed an accurate prediction of carbon dioxide and oxygen fluxes.

  9. Dynamical scaling analysis of plant callus growth

    NASA Astrophysics Data System (ADS)

    Galeano, J.; Buceta, J.; Juarez, K.; Pumariño, B.; de la Torre, J.; Iriondo, J. M.

    2003-07-01

    We present experimental results for the dynamical scaling properties of the development of plant calli. We have assayed two different species of plant calli, Brassica oleracea and Brassica rapa, under different growth conditions, and show that their dynamical scalings share a universality class. From a theoretical point of view, we introduce a scaling hypothesis for systems whose size evolves in time. We expect our work to be relevant for the understanding and characterization of other systems that undergo growth due to cell division and differentiation, such as, for example, tumor development.

  10. Growth inhibition of Candida by human oral epithelial cells.

    PubMed

    Steele, C; Leigh, J; Swoboda, R; Fidel, P L

    2000-11-01

    Oropharyngeal candidiasis (OPC) caused by Candida albicans is a significant problem in human immunodeficiency virus (HIV)-infected persons. Recognizing the paucity of information on innate and/or adaptive mucosal host defenses against C. albicans, we recently reported that human and nonhuman primate and mouse vaginal epithelial cells inhibit the growth of C. albicans in vitro. In the present study, oral epithelial cells collected from saliva of healthy volunteers and a purified oral epithelial cell line were found to inhibit blastoconidia and/or hyphal growth of several Candida species. Cell contact was a strict requirement for the epithelial cell anti-Candida activity; neither saliva nor culture supernatants alone inhibited Candida growth, and addition of saliva to the coculture did not modulate the epithelial cell activity. Finally, epithelial cell anti-Candida activity was significantly lower in HIV-infected persons with OPC. Together, these results suggest that oral epithelial cells may play a role in innate resistance against OPC.

  11. Inhibition of Bacillus subtilis growth and sporulation by threonine.

    PubMed

    Lamb, D H; Bott, K F

    1979-01-01

    A 1-mg/ml amount of threonine (8.4 mM) inhibited growth and sporulation of Bacillus subtilis 168. Inhibition of sporulation was efficiently reversed by valine and less efficiently by pyruvate, arginine, glutamine, and isoleucine. Inhibition of vegetative growth was reversed by asparate and glutamate as well as by valine, arginine, or glutamine. Cells in minimal growth medium were inhibited only transiently by very high concentrations of threonine, whereas inhibition of sporulation was permanent. Addition of threonine prevented the normal increase in alkaline phosphatase and reduced the production of extracellular protease by about 50%, suggesting that threonine blocked the sporulation process relatively early. 2-Ketobutyrate was able to mimic the effect of threonine on sporulation. Sporulation in a strain selected for resistance to azaleucine was partially resistant. Seventy-five percent of the mutants selected for the ability to grow vegetatively in the presence of high threonine concentrations were found to be simultaneously isoleucine auxotrophs. In at least one of these mutants, the threonine resistance phenotpye could not be dissociated from the isoleucine requirement by transformation. This mutation was closely linked to a known ilvA mutation (recombination index, 0.16). This strain also had reduced intracellular threonine deaminase activity. These results suggest that threonine inhibits B. subtilis by causing valine starvation.

  12. Thymoquinone Inhibits Escherichia coli ATP Synthase and Cell Growth

    PubMed Central

    Ahmad, Zulfiqar; Laughlin, Thomas F.; Kady, Ismail O.

    2015-01-01

    We examined the thymoquinone induced inhibition of purified F1 or membrane bound F1FO E. coli ATP synthase. Both purified F1 and membrane bound F1FO were completely inhibited by thymoquinone with no residual ATPase activity. The process of inhibition was fully reversible and identical in both membrane bound F1Fo and purified F1 preparations. Moreover, thymoquinone induced inhibition of ATP synthase expressing wild-type E. coli cell growth and non-inhibition of ATPase gene deleted null control cells demonstrates that ATP synthase is a molecular target for thymoquinone. This also links the beneficial dietary based antimicrobial and anticancer effects of thymoquinone to its inhibitory action on ATP synthase. PMID:25996607

  13. Autophagy contributes to gefitinib-induced glioma cell growth inhibition

    SciTech Connect

    Chang, Cheng-Yi; Kuan, Yu-Hsiang; Ou, Yen-Chuan; Li, Jian-Ri; Wu, Chih-Cheng; Pan, Pin-Ho; Chen, Wen-Ying; Huang, Hsuan-Yi; Chen, Chun-Jung

    2014-09-10

    Epidermal growth factor receptor tyrosine kinase inhibitors, including gefitinib, have been evaluated in patients with malignant gliomas. However, the molecular mechanisms involved in gefitinib-mediated anticancer effects against glioma are incompletely understood. In the present study, the cytostatic potential of gefitinib was demonstrated by the inhibition of glioma cell growth, long-term clonogenic survival, and xenograft tumor growth. The cytostatic consequences were accompanied by autophagy, as evidenced by monodansylcadaverine staining of acidic vesicle formation, conversion of microtubule-associated protein-1 light chain 3-II (LC3-II), degradation of p62, punctate pattern of GFP-LC3, and conversion of GFP-LC3 to cleaved-GFP. Autophagy inhibitor 3-methyladenosine and chloroquine and genetic silencing of LC3 or Beclin 1 attenuated gefitinib-induced growth inhibition. Gefitinib-induced autophagy was not accompanied by the disruption of the Akt/mammalian target of rapamycin signaling. Instead, the activation of liver kinase-B1/AMP-activated protein kinase (AMPK) signaling correlated well with the induction of autophagy and growth inhibition caused by gefitinib. Silencing of AMPK suppressed gefitinib-induced autophagy and growth inhibition. The crucial role of AMPK activation in inducing glioma autophagy and growth inhibition was further supported by the actions of AMP mimetic AICAR. Gefitinib was shown to be capable of reducing the proliferation of glioma cells, presumably by autophagic mechanisms involving AMPK activation. - Highlights: • Gefitinib causes cytotoxic and cytostatic effect on glioma. • Gefitinib induces autophagy. • Gefitinib causes cytostatic effect through autophagy. • Gefitinib induces autophagy involving AMPK.

  14. (Metabolic mechanisms of plant growth at low water potentials)

    SciTech Connect

    Not Available

    1990-01-01

    The work supported by DOE showed that water-limitation inhibits plant growth first by imposing a physical limitation that is followed in a few h by metabolic changes leading to reduced wall extensibility in the enlarging cells. After the wall extensibility decreased, a 28kD protein accumulated particularly in the walls of the growth-affected cells. Antibodies were used to identify cDNA for the protein. The base sequence of the cDNA was typical of an enzyme rather than known structural components of walls. The sequence was identical to one published by another laboratory at the same time and encoding a protein that accumulates in vacuoles of depodded soybean plants.

  15. Static Magnetic Field and Plant Growth

    NASA Astrophysics Data System (ADS)

    Maharramov, Akif A.

    2007-04-01

    In the conditions of stable existence of Static Magnetic Field (SMF) the growth processes of some plants' (chickpeas, beans and lentils) seeds have been investigated in different temperatures of microenvironment. It has been established that the rate of the plant growths is affected (speeded up) by SMF that is intimately related to environmental temperature, any other environmental parameters (humidity, illumination, soil chemical state, etc) being under control. At the same time, the highest rate of growth has been observed in beans at a range of 30, 0 +/- 2, 0 °C. Special experiments and analyses of the data obtained, testified that the plants roots occurred the main target for SMF to be affected to get increasing rate. In order to standardize experimental conditions, the SMF have been created by magnetic bars of the intensity of B, equal that of the Earth at a distance of 23 cm from a pole of a bar magnet on the line passing along the both of its poles. Taking as a basis the results, it may be concluded that SMF can affect plant growth process, being regarded as an environmental factor of ecological importance.

  16. Plant growth responses to polypropylene--biocontainers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The influence of bio-fillers incorporated into polypropylene (PP) on the growth of plants was evaluated. Biocontainers were created by injection molding of PP with 25-40% by weight of Osage orange tree, Paulownia tree, coffee tree wood or dried distillers grain and 5% by weight of maleated polypropy...

  17. Book Review: Plant Growth and Climate Change

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The technical book "Plant Growth and climate Change" (2006. James I.L. Morison and M.D. Morecroft, Eds. Blackwell Publishing. 213 pp.) was reviewed for the scientific readership of the peer-reviewed journal HortScience. The text is well organized into nine independently-authored chapters each of whi...

  18. [Growth characteristics of rock plant Pogonatherum paniceum].

    PubMed

    Wang, Haiyang; Peng, Li; Li, Shaocai; Bai, Baowei

    2005-08-01

    The study on the growth characters, above and underground biomass, and root-shoot ratio of Pogonatherum paniceum grown on three types of substrates and five types of habitats in Chongqing showed that there were significant differences in plant growth characters, including stalk basal diameter, plant canopy and height, root system area and depth, and maximum root length among five habitats. For shoot growth, though the plants grown on purple soil had the maximum stalk basal diameter (15.18 cm), canopy (3 086.77 cm2) and height (6.58 cm) while those grown on purple sandy rock had the minimum values (stalk basal diameter 10.89 cm, canopy 1 868.79 cm2, and height 60.75 cm). There were no significant differences among three types of substrates. As for root system, there were significant differences between sandy rocks and purple soil, the plants grown on sandy rocks having higher means of root system area (1 389.14 cm2 and 1 487.14 cm2) and maximum root length (45.83 cm and 39.24 cm) than those grown on purple soil (root system area 717.09 cm2, maximum root length 21.42 cm). The plants grown on sandy rock allocated more biomass to root system, and had higher root-shoot ratio, which was helpful for its fixation on rock and its endurance on the desiccation and arid of rock substrate.

  19. Recovery of Saccharomyces cerevisiae from ethanol - induced growth inhibition

    SciTech Connect

    Walker-Caprioglio, H.M.; Rodriguez, R.J.; Parks, L.W.

    1985-09-01

    Ethanol caused altered mobility of the lipophilic probe 1,6-diphenyl-1,3,5-hexatriene in plasma membrane preparations of Saccharomyces cerevisiae. Because lipids had been shown to protect yeast cells against ethanol toxicity, sterols, fatty acids, proteins, and combinations of these were tested; however, protection from growth inhibition was not seen. Ethanol-induced, prolonged lag periods and diminished growth rates in S. cerevisiae were reduced by an autoconditioning of the medium by the inoculum.

  20. A molecular framework for the inhibition of Arabidopsis root growth in response to boron toxicity.

    PubMed

    Aquea, Felipe; Federici, Fernan; Moscoso, Cristian; Vega, Andrea; Jullian, Pastor; Haseloff, Jim; Arce-Johnson, Patricio

    2012-04-01

    Boron is an essential micronutrient for plants and is taken up in the form of boric acid (BA). Despite this, a high BA concentration is toxic for the plants, inhibiting root growth and is thus a significant problem in semi-arid areas in the world. In this work, we report the molecular basis for the inhibition of root growth caused by boron. We show that application of BA reduces the size of root meristems, correlating with the inhibition of root growth. The decrease in meristem size is caused by a reduction of cell division. Mitotic cell number significantly decreases and the expression level of key core cell cycle regulators is modulated. The modulation of the cell cycle does not appear to act through cytokinin and auxin signalling. A global expression analysis reveals that boron toxicity induces the expression of genes related with abscisic acid (ABA) signalling, ABA response and cell wall modifications, and represses genes that code for water transporters. These results suggest that boron toxicity produces a reduction of water and BA uptake, triggering a hydric stress response that produces root growth inhibition.

  1. Water vapor recovery from plant growth chambers

    NASA Technical Reports Server (NTRS)

    Ray, R. J.; Newbold, D. D.; Colton, R. H.; Mccray, S. B.

    1991-01-01

    NASA is investigating the use of plant growth chambers (PGCs) for space missions and for bases on the moon and Mars. Key to successful development of PGCs is a system to recover and reuse the water vapor that is transpired from the leaves of the plants. A design is presented for a simple, reliable, membrane-based system that allows the recovery, purification, and reuse of the transpired water vapor through control of temperature and humidity levels in PGCs. The system is based on two membrane technologies: (1) dehumidification membrane modules to remove water vapor from the air, and (2) membrane contactors to return water vapor to the PGC (and, in doing so, to control the humidity and temperature within the PGC). The membrane-based system promises to provide an ideal, stable growth environment for a variety of plants, through a design that minimizes energy usage, volume, and mass, while maximizing simplicity and reliability.

  2. Inhibition of Naja kaouthia venom activities by plant polyphenols.

    PubMed

    Pithayanukul, Pimolpan; Ruenraroengsak, Pakatip; Bavovada, Rapepol; Pakmanee, Narumol; Suttisri, Rutt; Saen-oon, Suwipa

    2005-03-21

    Plant polyphenols from the aqueous extracts of Pentace burmanica, Pithecellobium dulce, Areca catechu and Quercus infectoria were tested for their inhibitory activities against Naja kaouthia (NK) venom by in vitro neutralization method. The first three extracts could completely inhibit the lethality of the venom at 4 LD50 concentration and the venom necrotizing activity at the minimum necrotizing dose while also inhibited up to 90% of the acetylcholinesterase activity of NK venom at much lower tannin concentrations than that of Quercus infectoria. The ED50 of plant tannins in inhibiting NK venom activities varied according to condensed tannins and their content in the extracts. Molecular docking of the complexes between alpha-cobratoxin and either hydrolysable or condensed tannins at their lowest energetic conformations were proposed. The anti-venom activities of these plant polyphenols by selectively blocking the nicotinic acetylcholine receptor and non-selectively by precipitation of the venom proteins were suggested.

  3. Paradigm shift in plant growth control.

    PubMed

    Körner, Christian

    2015-06-01

    For plants to grow they need resources and appropriate conditions that these resources are converted into biomass. While acknowledging the importance of co-drivers, the classical view is still that carbon, that is, photosynthetic CO2 uptake, ranks above any other drivers of plant growth. Hence, theory and modelling of growth traditionally is carbon centric. Here, I suggest that this view is not reflecting reality, but emerged from the availability of methods and process understanding at leaf level. In most cases, poorly understood processes of tissue formation and cell growth are governing carbon demand, and thus, CO2 uptake. Carbon can only be converted into biomass to the extent chemical elements other than carbon, temperature or cell turgor permit.

  4. Chlorinated englerins with selective inhibition of renal cancer cell growth.

    PubMed

    Akee, Rhone K; Ransom, Tanya; Ratnayake, Ranjala; McMahon, James B; Beutler, John A

    2012-03-23

    The chlorinated englerins (3-9) were isolated from Phyllanthus engleri and shown to selectively inhibit the growth of renal cancer cells. The compounds were shown to be extraction artifacts produced by exposure to chloroform decomposition products during their isolation. The most active compound, 3, was synthesized from englerin A (1). PMID:22280462

  5. Modulation of germination and growth of plants by meditation.

    PubMed

    Haid, M; Huprikar, S

    2001-01-01

    So called primitive peoples of the world share a philosophy that human interaction via ceremony or ritual can affect the natural world. Is it possible to affect the germination and growth of plants by imbuing them with an intent to stimulate or inhibit them? We conducted a double blind series of experiments to determine whether a process of meditation on the water (referred to as "treated") given to a controlled planting of green peas or wheat would affect their germination. Peas were given water treated with stimulating intent. Statistical analysis was done using contingency table, Fisher's test, and Mantel-Haenszel analysis. The germination rate of 504 seeds receiving treated water with stimulating intent was 60.3% compared to 51.8% for the 504 controls (p = 0.006, 0.047, 0.003 respectively). A similar experiment was conducted with wheat with the intent of inhibiting germination. The germination rate of 2970 wheat seeds receiving treated water with inhibitory intent was 70.7% versus 74.9% for 2970 controls (p < 0.001, 0.0001, 0.001 respectively). During the sixth run of the wheat (inhibition) experiment, the seedlings were harvested and individually weighed on the tenth day after planting to determine whether there was any difference in growth. The mass of the treated seedlings was statistically significantly lower (mean = 97 mg versus 106 mg for the controls) when compared by analysis of variance (p = 0.000056). We conclude that meditation upon the water supplied to green peas and wheat can affect their germination rates and growth.

  6. [Plant growth with limited water]. Performance report

    SciTech Connect

    Not Available

    1992-10-01

    When water is in short supply, soybean stem growth is inhibited by a physical limitation followed in a few hours by metabolic changes that reduce the extensibility of the cell walls. The extensibility then becomes the main limitation. With time, there is a modest recovery in extensibility along with an accumulation of a 28kD protein in the walls of the growth-affected cells. A 3lkD protein that was 80% similar in amino acid sequence also was present but did not accumulate in the walls of the stem cells. In the stem, growth was inhibited and the mRNA for the 28kD protein increased in response to water deprivation but the mRNA for the 3 1 kD protein did not. The roots continued to grow and the mRNA for the 28kD protein did not accumulate but the mRNA for the 3lkD protein did. Thus, there was a tissuespecific response of gene expression that correlated with the contrasting growth response to low water potential in the same seedlings. Further work using immunogold labeling, fluorescence labeling, and western blotting gave evidence that the 28kD protein is located in the cell wall as well as several compartments in the cytoplasm. Preliminary experiments indicate that the 28kD protein is a phosphatase.

  7. Hormone activities and the cell cycle machinery in immunity-triggered growth inhibition.

    PubMed

    Reitz, M U; Gifford, M L; Schäfer, P

    2015-04-01

    Biotic stress and diseases caused by pathogen attack pose threats in crop production and significantly reduce crop yields. Enhancing immunity against pathogens is therefore of outstanding importance in crop breeding. However, this must be balanced, as immune activation inhibits plant growth. This immunity-coupled growth trade-off does not support resistance but is postulated to reflect the reallocation of resources to drive immunity. There is, however, increasing evidence that growth-immunity trade-offs are based on the reconfiguration of hormone pathways, shared by growth and immunity signalling. Studies in roots revealed the role of hormones in orchestrating growth across different cell types, with some hormones showing a defined cell type-specific activity. This is apparently highly relevant for the regulation of the cell cycle machinery and might be part of the growth-immunity cross-talk. Since plants are constantly exposed to Immuno-activating microbes under agricultural conditions, the transition from a growth to an immunity operating mode can significantly reduce crop yield and can conflict our efforts to generate next-generation crops with improved yield under climate change conditions. By focusing on roots, we outline the current knowledge of hormone signalling on the cell cycle machinery to explain growth trade-offs induced by immunity. By referring to abiotic stress studies, we further introduce how root cell type-specific hormone activities might contribute to growth under immunity and discuss the feasibility of uncoupling the growth-immunity cross-talk.

  8. Circularly Polarized Light and Growth of Plants

    NASA Astrophysics Data System (ADS)

    Shibayev, Pavel; Pergolizzi, Robert

    2011-03-01

    The influence of linearly polarized light on the direction of plants growth has been recently demonstrated. The state of circularly polarized (CP) light can also change when it is reflected from the surface of leaves and stems. However, the role of light handedness in the development of plants and CP light interaction with the complexes of chlorophyll molecules have still not been studied enough. In this work, the role of left CP light in the accelerated growth of lentil and pea plants is revealed and studied. The mechanism of such an enhancement is discussed in terms of the model considering transmission, absorption, and scattering of CP light on micro and macro levels of leaf organization. Theoretical modeling of light interaction with the interior of the leaf was conducted for a number of recently proposed models of organization of chlorophyll molecules and chloroplasts. All the calculations were performed by employing a 4x4 matrix method in solving Maxwell equations. It is shown that left-handed chiral organization of chlorophyll molecules can greatly enhance the absorption of light and therefore lead to the enhanced growth of the whole plant under CP light.

  9. Sensitivity of the Entomogenous Fungus Beauveria bassiana to Selected Plant Growth Regulators and Spray Additives

    PubMed Central

    Storey, Greggory K.; Gardner, Wayne A.

    1986-01-01

    Mefluidide was the only one of four plant growth regulators that caused little to no significant inhibition of in vitro germination and growth of the entomogenous fungus Beauveria bassiana. Silaid, paclobutrazol, and flurprimidol significantly inhibited germination and growth. Mortality of fall armyworm, Spodoptera frugiperda, resulting from B. bassiana was significantly reduced when larvae were exposed to conidia plus soil treated with paclobutrazol. Larval mortality resulting from conidia plus soil treated with mefluidide did not differ significantly from mortality resulting from untreated conidia. Triton CS-7 was the only one of eight spray adjuvants that significantly inhibited germination of B. bassiana conidia. PMID:16347095

  10. Saccharin and Cyclamate Inhibit Binding of Epidermal Growth Factor

    NASA Astrophysics Data System (ADS)

    Lee, L. S.

    1981-02-01

    The binding of 125I-labeled mouse epidermal growth factor (EGF) to 18 cell lines, including HeLa (human carcinoma), MDCK (dog kidney cells), HTC (rat hepatoma), K22 (rat liver), HF (human foreskin), GM17 (human skin fibroblasts), XP (human xeroderma pigmentosum fibroblasts), and 3T3-L1 (mouse fibroblasts), was inhibited by saccharin and cyclamate. The human cells were more sensitive to inhibition by these sweeteners than mouse or rat cells. EGF at doses far above the physiological levels reversed the inhibition in rodent cells but not in HeLa cells. In HeLa cells, the doses of saccharin and cyclamate needed for 50% inhibition were 3.5 and 9.3 mg/ml, respectively. Glucose, 2-deoxyglucose, sucrose, and xylitol did not inhibit EGF binding. Previous studies have shown that phorbol esters, strongly potent tumor promoters, also inhibit EGF binding to tissue culture cells. To explain the EGF binding inhibition by such greatly dissimilar molecules as phorbol esters, saccharin, and cyclamate, it is suggested that they operate through the activation of a hormone response control unit.

  11. Inhibition of tumor growth by elimination of granulocytes

    PubMed Central

    1995-01-01

    As observed for many types of cancers, heritable variants of ultraviolet light-induced tumors often grow more aggressively than the parental tumors. The aggressive growth of some variants is due to the loss of a T cell-recognized tumor-specific antigen; however, other variants retain such antigens. We have analyzed an antigen retention variant and found that the variant tumor cells grow at the same rate as the parental tumor cells in vitro, but grew more rapidly than the parental cells in the T cell-deficient host. The growth of the variant cells was stimulated in vitro by factors released from tumor-induced leukocytes and by several defined growth factors. In addition, the variant cancer cells actually attracted more leukocytes in vitro than the parental cells. Furthermore, elimination of granulocytes in vivo in nude mice by a specific antigranulocyte antibody inhibited the growth of the variant cancer, indicating that this tumor requires granulocytes for rapid growth. PMID:7807024

  12. Condensate Recycling in Closed Plant Growth Chambers

    NASA Technical Reports Server (NTRS)

    Bledsoe, J. O.; Sager, J. C.; Fortson, R. E.

    1994-01-01

    Water used in the the Controlled Ecological Life Support System (CELSS) Breadboard Project at the Kennedy Space Center is being recycled. Condensation is collected in the air ducts, filtered and deionized, and resupplied to the system for nutrient solutions, supplemental humidification, solvents and diluents. While the system functions well from a process control standpoint, precise and accurate tracking of water movement through the system to answer plant physiological questions is not consistent. Possible causes include hardware errors, undetected vapor loss from chamber leakage, and unmeasured changes in water volume in the plant growth trays.

  13. 22-Oxocholestanes as plant growth promoters.

    PubMed

    Zeferino-Diaz, Reyna; Hilario-Martinez, J Ciciolil; Rodriguez-Acosta, Maricela; Sandoval-Ramirez, Jesus; Fernandez-Herrera, Maria A

    2015-06-01

    The spirostanic steroidal side-chain of diosgenin and hecogenin was modified to produce 22-oxocholestane derivatives. This type of side-chain was obtained in good yields through a straightforward four-step pathway. These compounds show potent brassinosteroid-like growth promoting activity evaluated via the rice lamina joint inclination bioassay. This is the first report of steroidal skeletons bearing the 22-oxocholestane side-chain and preserving the basic structure (A-D rings) from their corresponding parent compounds acting as plant growth promoters.

  14. 22-Oxocholestanes as plant growth promoters.

    PubMed

    Zeferino-Diaz, Reyna; Hilario-Martinez, J Ciciolil; Rodriguez-Acosta, Maricela; Sandoval-Ramirez, Jesus; Fernandez-Herrera, Maria A

    2015-06-01

    The spirostanic steroidal side-chain of diosgenin and hecogenin was modified to produce 22-oxocholestane derivatives. This type of side-chain was obtained in good yields through a straightforward four-step pathway. These compounds show potent brassinosteroid-like growth promoting activity evaluated via the rice lamina joint inclination bioassay. This is the first report of steroidal skeletons bearing the 22-oxocholestane side-chain and preserving the basic structure (A-D rings) from their corresponding parent compounds acting as plant growth promoters. PMID:25795152

  15. Klebsiella pneumoniae inoculants for enhancing plant growth

    SciTech Connect

    Triplett, Eric W.; Kaeppler, Shawn M.; Chelius, Marisa K.

    2008-07-01

    A biological inoculant for enhancing the growth of plants is disclosed. The inoculant includes the bacterial strains Herbaspirillum seropedicae 2A, Pantoea agglomerans P101, Pantoea agglomerans P102, Klebsiella pneumoniae 342, Klebsiella pneumoniae zmvsy, Herbaspirillum seropedicae Z152, Gluconacetobacter diazotrophicus PA15, with or without a carrier. The inoculant also includes strains of the bacterium Pantoea agglomerans and K. pneumoniae which are able to enhance the growth of cereal grasses. Also disclosed are the novel bacterial strains Herbaspirillum seropedicae 2A, Pantoea agglomerans P101 and P102, and Klebsiella pneumoniae 342 and zmvsy.

  16. Clonal growth and plant species abundance

    PubMed Central

    Herben, Tomáš; Nováková, Zuzana; Klimešová, Jitka

    2014-01-01

    Background and Aims Both regional and local plant abundances are driven by species' dispersal capacities and their abilities to exploit new habitats and persist there. These processes are affected by clonal growth, which is difficult to evaluate and compare across large numbers of species. This study assessed the influence of clonal reproduction on local and regional abundances of a large set of species and compared the predictive power of morphologically defined traits of clonal growth with data on actual clonal growth from a botanical garden. The role of clonal growth was compared with the effects of seed reproduction, habitat requirements and growth, proxied both by LHS (leaf–height–seed) traits and by actual performance in the botanical garden. Methods Morphological parameters of clonal growth, actual clonal reproduction in the garden and LHS traits (leaf-specific area – height – seed mass) were used as predictors of species abundance, both regional (number of species records in the Czech Republic) and local (mean species cover in vegetation records) for 836 perennial herbaceous species. Species differences in habitat requirements were accounted for by classifying the dataset by habitat type and also by using Ellenberg indicator values as covariates. Key Results After habitat differences were accounted for, clonal growth parameters explained an important part of variation in species abundance, both at regional and at local levels. At both levels, both greater vegetative growth in cultivation and greater lateral expansion trait values were correlated with higher abundance. Seed reproduction had weaker effects, being positive at the regional level and negative at the local level. Conclusions Morphologically defined traits are predictive of species abundance, and it is concluded that simultaneous investigation of several such traits can help develop hypotheses on specific processes (e.g. avoidance of self-competition, support of offspring) potentially

  17. Salt stress inhibits germination and early seedling growth in cabbage (Brassica oleracea capitata L.).

    PubMed

    Jamil, M; Lee, Kyeong Bo; Jung, Kwang Yong; Lee, Deog Bae; Han, Mi Suk; Rha, Eui Shik

    2007-03-15

    Salinity induced inhibition in germination and early stages of cabbage (Brassica oleracea capitata L.) [two varieties (autumn cabbage and spring cabbage)] were measured in response to increasing NaCl concentration. The salinity (NaCl) concentrations in solution were 0 (control), 4.7, 9.4 and 14.1 dS m(-1). Different concentrations of salt stress had considerable effect on germination, germination rate (1/t50, where t50 is the time to 50% of germination), root and shoot lengths, root, shoot and plant fresh weight of cabbage. Final germination in cabbage (autumn cabbage and spring cabbage) showed significant inhibition with increasing salt stress up to 14.1 dS m(-1) NaCl. The required time for germination increased with increasing concentration of salt. The seedling growth was strongly inhibited by all salt levels, particularly at 14.1 dS m(-1). Furthermore Root growth was more affected then shoots growth by salt stress. Fresh weights of root, shoot and plant were also severely affected by different salinity treatments. Linear regression revealed a significant negative relationship between salinity and final germination, germination rate, root and shoot lengths and fresh weights of roots, shoots and plants.

  18. Root Growth Inhibition in Boron-Deficient or Aluminum-Stressed Squash May Be a Result of Impaired Ascorbate Metabolism.

    PubMed Central

    Lukaszewski, K. M.; Blevins, D. G.

    1996-01-01

    Although cessation of growth is the most apparent symptom of boron deficiency, the biochemical function of boron in growth processes is not well understood. We propose that the action of boron in root meristems is associated with ascorbate metabolism. Total inhibition of root growth in squash (Cucurbita pepo L.) plants transferred to boron-free medium coincided with a major decrease (up to 98%) in the ascorbate concentration of root apices. Under low-boron conditions, in which root growth was partially inhibited, ascorbate concentration declined in proportion to growth rate. The decline in ascorbate concentration in boron-deficient root tips was not related to ascorbate oxidation. Ascorbate added to the medium improved root growth in plants supplied with insufficient boron. Increasing concentrations of aluminum in the nutrient medium caused progressive inhibition of root growth and a parallel reduction in ascorbate concentration of root apices. Elevated boron levels improved root growth under toxic aluminum conditions and produced root apices with higher ascorbate concentrations. To our knowledge, this is the first report of a correlation between boron nutrition, ascorbate concentration in root apices, and growth. These findings show that root growth inhibition resulting from either boron deficiency or aluminum toxicity may be a consequence of disrupted ascorbate metabolism. PMID:12226437

  19. Inhibition of tomato shoot growth by over-irrigation is linked to nitrogen deficiency and ethylene.

    PubMed

    Fiebig, Antje; Dodd, Ian C

    2016-01-01

    Although physiological effects of acute flooding have been well studied, chronic effects of suboptimal soil aeration caused by over-irrigation of containerized plants have not, despite its likely commercial significance. By automatically scheduling irrigation according to soil moisture thresholds, effects of over-irrigation on soil properties (oxygen concentration, temperature and moisture), leaf growth, gas exchange, phytohormone [abscisic acid (ABA) and ethylene] relations and nutrient status of tomato (Solanum lycopersicum Mill. cv. Ailsa Craig) were studied. Over-irrigation slowly increased soil moisture and decreased soil oxygen concentration by 4%. Soil temperature was approximately 1°C lower in the over-irrigated substrate. Over-irrigating tomato plants for 2 weeks significantly reduced shoot height (by 25%) and fresh weight and total leaf area (by 60-70%) compared with well-drained plants. Over-irrigation did not alter stomatal conductance, leaf water potential or foliar ABA concentrations, suggesting that growth inhibition was not hydraulically regulated or dependent on stomatal closure or changes in ABA. However, over-irrigation significantly increased foliar ethylene emission. Ethylene seemed to inhibit growth, as the partially ethylene-insensitive genotype Never ripe (Nr) was much less sensitive to over-irrigation than the wild type. Over-irrigation induced significant foliar nitrogen deficiency and daily supplementation of small volumes of 10 mM Ca(NO3 )2 to over-irrigated soil restored foliar nitrogen concentrations, ethylene emission and shoot fresh weight of over-irrigated plants to control levels. Thus reduced nitrogen uptake plays an important role in inhibiting growth of over-irrigated plants, in part by stimulating foliar ethylene emission. PMID:25950248

  20. Phenolic-rich leaf carbon fractions differentially influence microbial respiration and plant growth.

    PubMed

    Meier, Courtney L; Bowman, William D

    2008-11-01

    Phenolics can reduce soil nutrient availability, either indirectly by stimulating microbial nitrogen (N) immobilization or directly by enhancing physical protection within soil. Phenolic-rich plants may therefore negatively affect neighboring plant growth by restricting the N supply. We used a slow-growing, phenolic-rich alpine forb, Acomastylis rossii, to test the hypothesis that phenolic-rich carbon (C) fractions stimulate microbial population growth and reduce plant growth. We generated low-molecular-weight (LMW) fractions, tannin fractions, and total soluble C fractions from A. rossii and measured their effects on soil respiration and growth of Deschampsia caespitosa, a fast-growing, co-dominant grass. Fraction effects fell into two distinct categories: (1) fractions did not increase soil respiration and killed D. caespitosa plants, or (2) fractions stimulated soil respiration and reduced plant growth and plant N concentration while simultaneously inhibiting root growth. The LMW phenolic-rich fractions increased soil respiration and reduced plant growth more than tannins. These results suggest that phenolic compounds can inhibit root growth directly as well as indirectly affect growth by reducing pools of plant available N by stimulating soil microbes. Both mechanisms illustrate how below-ground phenolic effects may influence the growth of neighboring plants. We also examined patterns of foliar phenolic concentrations among populations of A. rossii across a natural productivity gradient (productivity was used as a proxy for competition intensity). Concentrations of some LMW phenolics increased significantly in more productive sites where A. rossii is a competitive equal with the faster growing D. caespitosa. Taken together, our results contribute important information to the growing body of evidence indicating that the quality of C moving from plants to soils can have significant effects on neighboring plant performance, potentially associated with phytoxic

  1. Calcite crystal growth inhibition by humic substances with emphasis on hydrophobic acids from the Florida Everglades

    USGS Publications Warehouse

    Hoch, A.R.; Reddy, M.M.; Aiken, G.R.

    2000-01-01

    The crystallization of calcium carbonate minerals plays an integral role in the water chemistry of terrestrial ecosystems. Humic substances, which are ubiquitous in natural waters, have been shown to reduce or inhibit calcite crystal growth in experiments. The purpose of this study is to quantify and understand the kinetic effects of hydrophobic organic acids isolated from the Florida Everglades and a fulvic acid from Lake Fryxell, Antarctica, on the crystal growth of calcite (CaCO3). Highly reproducible calcite growth experiments were performed in a sealed reactor at constant pH, temperature, supersaturation (?? = 4.5), P(CO2) (10-3.5atm), and ionic strength (0.1 M) with various concentrations of organic acids. Higher plant-derived aquatic hydrophobic acids from the Everglades were more effective growth inhibitors than microbially derived fulvic acid from Lake Fryxell. Organic acid aromaticity correlated strongly with growth inhibition. Molecular weight and heteroatom content correlated well with growth inhibition, whereas carboxyl content and aliphatic nature did not. Copyright (C) 1999 Elsevier Science Ltd.

  2. Operational development of small plant growth systems

    NASA Technical Reports Server (NTRS)

    Scheld, H. W.; Magnuson, J. W.; Sauer, R. L.

    1986-01-01

    The results of a study undertaken on the first phase of an empricial effort in the development of small plant growth chambers for production of salad type vegetables on space shuttle or space station are discussed. The overall effort is visualized as providing the underpinning of practical experience in handling of plant systems in space which will provide major support for future efforts in planning, design, and construction of plant-based (phytomechanical) systems for support of human habitation in space. The assumptions underlying the effort hold that large scale phytomechanical habitability support systems for future space stations must evolve from the simple to the complex. The highly complex final systems will be developed from the accumulated experience and data gathered from repetitive tests and trials of fragments or subsystems of the whole in an operational mode. These developing system components will, meanwhile, serve a useful operational function in providing psychological support and diversion for the crews.

  3. Plant growth promotion by phosphate solubilizing bacteria.

    PubMed

    Zaidi, A; Khan, M S; Ahemad, M; Oves, M

    2009-09-01

    Most agronomic soils contain large reserves of total phosphorus [P], but the fixation and precipitation of P cause P deficiency, and in turn, restrict the growth of crops severely. Phosphorus replenishment, especially in sustainable production systems, remains a major challenge as it is mainly fertilizer-dependent. Though the use of chemical P fertilizers is obviously the best means to circumvent P deficiency in different agro-ecosystems, their use is always limited due to its spiralling cost. A greater interest has, therefore, been generated to find an alternative yet inexpensive technology that could provide sufficient P to plants while reducing the dependence on expensive chemical P fertilizers. Among the heterogeneous and naturally abundant microbes inhabiting the rhizosphere, the phosphate solubilizing microorganisms (PSM) including bacteria have provided an alternative biotechnological solution in sustainable agriculture to meet the P demands of plants. These organisms in addition to providing P to plants also facilitate plant growth by other mechanisms. Despite their different ecological niches and multiple functional properties, P-solubilizing bacteria have yet to fulfil their promise as commercial bio-inoculants. Current developments in our understanding of the functional diversity, rhizosphere colonizing ability, mode of actions and judicious application are likely to facilitate their use as reliable components in the management of sustainable agricultural systems. PMID:19789141

  4. Mechanism of sulfate transport inhibition by cycloheximide in plant tissues.

    PubMed

    Renosto, F; Ferrari, G

    1975-10-01

    Inhibition by cycloheximide of sulfate transport in both barley roots (Hordeum vulgare L.) and potato tuber (Solanum tuberosum L.) increases with increasing inhibitor concentration only to a limited extent, depending on the length of the tissue incubation with the inhibitor. In contrast to this, increasing concentrations of dinitrophenol have a rapid and total inhibitory effect on the active transport. Leucine transport in the same tissues is strongly inhibited by dinitrophenol but is not affected by cycloheximide, whereas incorporation into protein is mainly inhibited by cycloheximide. It appears that the mechanism of transport inhibition by cycloheximide in plant tissues consists in stopping new carrier synthesis and not in the disruption of energy flow. Sulfate carriers show comparable decay rates in barley roots and potato tuber, the mean life being shorter than that of the leucine carriers. These appear more stable in roots than in storage tissues.

  5. Identification of volatile compounds produced by the bacterium Burkholderia tropica that inhibit the growth of fungal pathogens

    PubMed Central

    Tenorio-Salgado, Silvia; Tinoco, Raunel; Vazquez-Duhalt, Rafael; Caballero-Mellado, Jesus; Perez-Rueda, Ernesto

    2013-01-01

    It has been documented that bacteria from the Burkholderia genera produce different kinds of compounds that inhibit plant pathogens, however in Burkholderia tropica, an endophytic diazotrophic and phosphate-solubilizing bacterium isolated from a wide diversity of plants, the capacity to produce antifungal compounds has not been evaluated. In order to expand our knowledge about Burkholderia tropica as a potential biological control agent, we analyzed 15 different strains of this bacterium to evaluate their capacities to inhibit the growth of four phytopathogenic fungi, Colletotrichum gloeosporioides, Fusarium culmorum, Fusarium oxysporum and Sclerotium rolffsi. Diverse analytical techniques, including plant root protection and dish plate growth assays and gas chromatography-mass spectroscopy showed that the fungal growth inhibition was intimately associated with the volatile compounds produced by B. tropica and, in particular, two bacterial strains (MTo293 and TTe203) exhibited the highest radial mycelial growth inhibition. Morphological changes associated with these compounds, such as disruption of fungal hyphae, were identified by using photomicrographic analysis. By using gas chromatography-mass spectroscopy technique, 18 volatile compounds involved in the growth inhibition mechanism were identified, including α-pinene and limonene. In addition, we found a high proportion of bacterial strains that produced siderophores during growth with different carbon sources, such as alanine and glutamic acid; however, their roles in the antagonism mechanism remain unclear. PMID:23680857

  6. Allelochemical L-DOPA induces quinoprotein adducts and inhibits NADH dehydrogenase activity and root growth of cucumber.

    PubMed

    Mushtaq, Muhammad Naeem; Sunohara, Yukari; Matsumoto, Hiroshi

    2013-09-01

    Allelochemical L-DOPA (l-3,4-dihydroxyphenylalanine) inhibits growth of several plant species. However, its mode of action is not well clarified in plants. The present studies were conducted to explore the action mechanism of L-DOPA in cucumber roots. The results revealed that L-DOPA suppressed the root growth of cucumber and induced quinoprotein and melanin formation in the roots. Moreover, L-DOPA not only decreased mitochondrial viability and NADH dehydrogenase (complex I) activity but also increased quinoprotein formation in vitro in isolated mitochondria from cucumber roots. Strong correlations were observed between quinoprotein formation and root growth inhibition, quinoprotein formation and NADH dehydrogenase activity, after L-DOPA treatment. The results suggest that quinoprotein formation and mitochondrial impairment might be involved in growth-inhibition mechanism of L-DOPA in cucumber roots. PMID:23831820

  7. Comparison of signaling interactions determining annual and perennial plant growth in response to low temperature

    PubMed Central

    Wingler, Astrid

    2015-01-01

    Low temperature inhibits plant growth despite the fact that considerable rates of photosynthetic activity can be maintained. Instead of lower rates of photosynthesis, active inhibition of cell division and expansion is primarily responsible for reduced growth. This results in sink limitation and enables plants to accumulate carbohydrates that act as compatible solutes or are stored throughout the winter to enable re-growth in spring. Regulation of growth in response to temperature therefore requires coordination with carbon metabolism, e.g., via the signaling metabolite trehalose-6-phosphate. The phytohormones gibberellin (GA) and jasmonate (JA) play an important role in regulating growth in response to temperature. Growth restriction at low temperature is mainly mediated by DELLA proteins, whose degradation is promoted by GA. For annual plants, it has been shown that the GA/DELLA pathway interacts with JA signaling and C-repeat binding factor dependent cold acclimation, but these interactions have not been explored in detail for perennials. Growth regulation in response to seasonal factors is, however, particularly important in perennials, especially at high latitudes. In autumn, growth cessation in trees is caused by shortening of the daylength in interaction with phytohormone signaling. In perennial grasses seasonal differences in the sensitivity to GA may enable enhanced growth in spring. This review provides an overview of the signaling interactions that determine plant growth at low temperature and highlights gaps in our knowledge, especially concerning the seasonality of signaling responses in perennial plants. PMID:25628637

  8. Myxostiolide, myxostiol, and clavatoic acid, plant growth regulators from the fungus Myxotrichum stipitatum.

    PubMed

    Kimura, Yasuo; Shimada, Atsumi; Kusano, Miyako; Yoshii, Katsunobu; Morita, Akiko; Nishibe, Masahiko; Fujioka, Shozo; Kawano, Tsuyoshi

    2002-04-01

    New plant growth regulators, named myxostiolide (1), myxostiol (2), and clavatoic acid (3), have been isolated from Myxotrichum stipitatum, and their structures have been established by spectroscopic methods including 2D NMR. The biological activities of 1, 2, and 3 have been examined using tea pollen and lettuce seedling bioassay methods. With tea pollen, compound 1 inhibited the pollen tube growth to 14% of control at a concentration of 100 mg/L. With lettuce seedlings, compound 2 accelerated the root growth from 1 mg/L to 100 mg/L and compound 3 inhibited the root growth, to 52% of control, at a concentration of 100 mg/L.

  9. The Arabidopsis transcription factor ABIG1 relays ABA signaled growth inhibition and drought induced senescence

    PubMed Central

    Liu, Tie; Longhurst, Adam D; Talavera-Rauh, Franklin; Hokin, Samuel A; Barton, M Kathryn

    2016-01-01

    Drought inhibits plant growth and can also induce premature senescence. Here we identify a transcription factor, ABA INSENSITIVE GROWTH 1 (ABIG1) required for abscisic acid (ABA) mediated growth inhibition, but not for stomatal closure. ABIG1 mRNA levels are increased both in response to drought and in response to ABA treatment. When treated with ABA, abig1 mutants remain greener and produce more leaves than comparable wild-type plants. When challenged with drought, abig1 mutants have fewer yellow, senesced leaves than wild-type. Induction of ABIG1 transcription mimics ABA treatment and regulates a set of genes implicated in stress responses. We propose a model in which drought acts through ABA to increase ABIG1 transcription which in turn restricts new shoot growth and promotes leaf senescence. The results have implications for plant breeding: the existence of a mutant that is both ABA resistant and drought resistant points to new strategies for isolating drought resistant genetic varieties. DOI: http://dx.doi.org/10.7554/eLife.13768.001 PMID:27697148

  10. Growth inhibition of Mycobacterium smegmatis by mycobacteriophage-derived enzymes.

    PubMed

    Grover, Navdeep; Paskaleva, Elena E; Mehta, Krunal K; Dordick, Jonathan S; Kane, Ravi S

    2014-09-01

    We report the ability of mycobacteriophage-derived endolysins to inhibit the growth of Mycobacterium smegmatis. We expressed and purified LysB from mycobacteriophage Bxz2 and compared its activity with that of a previously reported LysB from mycobacteriophage Ms6. The esterase activity of Bxz2 LysB with pNP esters was 10-fold higher than that of the previously reported LysB but its lipolytic activity was significantly lower. The presence of surfactant - Tween 80 or Triton X-100 - significantly increased the activity of LysB. Characterization of LysB-treated M. smegmatis cells and LysB-treated purified cell wall by mass spectroscopy confirmed the hydrolytic activity of the enzyme. Both enzymes were equally effective in inhibiting the growth of M. smegmatis, demonstrating their potential as bacteriostatic agents.

  11. Plant hormone jasmonate prioritizes defense over growth by interfering with gibberellin signaling cascade.

    PubMed

    Yang, Dong-Lei; Yao, Jian; Mei, Chuan-Sheng; Tong, Xiao-Hong; Zeng, Long-Jun; Li, Qun; Xiao, Lang-Tao; Sun, Tai-ping; Li, Jigang; Deng, Xing-Wang; Lee, Chin Mei; Thomashow, Michael F; Yang, Yinong; He, Zuhua; He, Sheng Yang

    2012-05-01

    Plants must effectively defend against biotic and abiotic stresses to survive in nature. However, this defense is costly and is often accompanied by significant growth inhibition. How plants coordinate the fluctuating growth-defense dynamics is not well understood and remains a fundamental question. Jasmonate (JA) and gibberellic acid (GA) are important plant hormones that mediate defense and growth, respectively. Binding of bioactive JA or GA ligands to cognate receptors leads to proteasome-dependent degradation of specific transcriptional repressors (the JAZ or DELLA family of proteins), which, at the resting state, represses cognate transcription factors involved in defense (e.g., MYCs) or growth [e.g. phytochrome interacting factors (PIFs)]. In this study, we found that the coi1 JA receptor mutants of rice (a domesticated monocot crop) and Arabidopsis (a model dicot plant) both exhibit hallmark phenotypes of GA-hypersensitive mutants. JA delays GA-mediated DELLA protein degradation, and the della mutant is less sensitive to JA for growth inhibition. Overexpression of a selected group of JAZ repressors in Arabidopsis plants partially phenocopies GA-associated phenotypes of the coi1 mutant, and JAZ9 inhibits RGA (a DELLA protein) interaction with transcription factor PIF3. Importantly, the pif quadruple (pifq) mutant no longer responds to JA-induced growth inhibition, and overexpression of PIF3 could partially overcome JA-induced growth inhibition. Thus, a molecular cascade involving the COI1-JAZ-DELLA-PIF signaling module, by which angiosperm plants prioritize JA-mediated defense over growth, has been elucidated.

  12. Making phytoremediation work better: maximizing a plant's growth potential in the midst of adversity.

    PubMed

    Glick, Bernard R; Stearns, Jennifer C

    2011-01-01

    While a number of different plants can either breakdown a variety of organic contaminants or hyperaccumulate metals from the environment, even the most efficient of those plants is typically inhibited by the presence of the toxicant(s). The plant stress that is induced by the presence of various environmental toxicants typically limits a plant's growth and ultimately its ability to phytoremediate the toxicant(s). Here, it is argued that the simple strategy of adding plant growth-promoting bacteria (preferably endophytes) that reduce plant ethylene levels by ACC deaminase activity and have the ability to synthesize the phytohoromone IAA, and are used to phytoremediate various toxicants can significantly (and often dramatically) increase both plant growth and phytoremediation activity in the presence of those toxicants. PMID:22046748

  13. [Review on application of plant growth retardants in medicinal plants cultivation].

    PubMed

    Zhai, Yu-Yao; Guo, Bao-Lin; Cheng, Ming

    2013-09-01

    Plant growth retardants are widely used in cultivation of medicinal plant, but there is still lack of scientific guidance. In order to guide the use of plant growth retardants in medicinal plant cultivation efficiently and reasonably, this paper reviewed the mechanism, function characteristic, plant and soil residue of plant growth retardants, such as chlorocholine chloride, mepiquat chloride, paclobutrazol, unicnazle and succinic acid, and summarized the application of plant growth retardants in medicinal plants cultivation in recent years, with focus on the effect of growth and yield of the officinal organs and secondary metabolites.

  14. Nordihydroguaiaretic Acid Inhibits Insulin-Like Growth Factor Signaling, Growth, and Survival in Human Neuroblastoma Cells

    PubMed Central

    Meyer, Gary E.; Chesler, Louis; Liu, Dandan; Gable, Karissa; Maddux, Betty A.; Goldenberg, David D.; Youngren, Jack F.; Goldfine, Ira D.; Weiss, William A.; Matthay, Katherine K.; Rosenthal, Stephen M.

    2010-01-01

    Neuroblastoma is a common pediatric malignancy that metastasizes to the liver, bone, and other organs. Children with metastatic disease have a less than 50% chance of survival with current treatments. Insulin-like growth factors (IGFs) stimulate neuroblastoma growth, survival, and motility, and are expressed by neuroblastoma cells and the tissues they invade. Thus, therapies that disrupt the effects of IGFs on neuroblastoma tumorigenesis may slow disease progression. We show that NVP-AEW541, a specific inhibitor of the IGF-I receptor (IGF-IR), potently inhibits neuroblastoma growth in vitro. Nordihydroguaiaretic acid (NDGA), a phenolic compound isolated from the creosote bush (Larrea divaricata), has anti-tumor properties against a number of malignancies, has been shown to inhibit the phosphorylation and activation of the IGF-IR in breast cancer cells, and is currently in Phase I trials for prostate cancer. In the present study in neuroblastoma, NDGA inhibits IGF-I-mediated activation of the IGF-IR and disrupts activation of ERK and Akt signaling pathways induced by IGF-I. NDGA inhibits growth of neuroblastoma cells and induces apoptosis at higher doses, causing IGF-I-resistant activation of caspase-3 and a large increase in the fraction of sub-G0 cells. In addition, NDGA inhibits the growth of xenografted human neuroblastoma tumors in nude mice. These results indicate that NDGA may be useful in the treatment of neuroblastoma and may function in part via disruption of IGF-IR signaling. PMID:17486636

  15. Nordihydroguaiaretic acid inhibits insulin-like growth factor signaling, growth, and survival in human neuroblastoma cells.

    PubMed

    Meyer, Gary E; Chesler, Louis; Liu, Dandan; Gable, Karissa; Maddux, Betty A; Goldenberg, David D; Youngren, Jack F; Goldfine, Ira D; Weiss, William A; Matthay, Katherine K; Rosenthal, Stephen M

    2007-12-15

    Neuroblastoma is a common pediatric malignancy that metastasizes to the liver, bone, and other organs. Children with metastatic disease have a less than 50% chance of survival with current treatments. Insulin-like growth factors (IGFs) stimulate neuroblastoma growth, survival, and motility, and are expressed by neuroblastoma cells and the tissues they invade. Thus, therapies that disrupt the effects of IGFs on neuroblastoma tumorigenesis may slow disease progression. We show that NVP-AEW541, a specific inhibitor of the IGF-I receptor (IGF-IR), potently inhibits neuroblastoma growth in vitro. Nordihydroguaiaretic acid (NDGA), a phenolic compound isolated from the creosote bush (Larrea divaricata), has anti-tumor properties against a number of malignancies, has been shown to inhibit the phosphorylation and activation of the IGF-IR in breast cancer cells, and is currently in Phase I trials for prostate cancer. In the present study in neuroblastoma, NDGA inhibits IGF-I-mediated activation of the IGF-IR and disrupts activation of ERK and Akt signaling pathways induced by IGF-I. NDGA inhibits growth of neuroblastoma cells and induces apoptosis at higher doses, causing IGF-I-resistant activation of caspase-3 and a large increase in the fraction of sub-G0 cells. In addition, NDGA inhibits the growth of xenografted human neuroblastoma tumors in nude mice. These results indicate that NDGA may be useful in the treatment of neuroblastoma and may function in part via disruption of IGF-IR signaling.

  16. Tumor suppressor XAF1 induces apoptosis, inhibits angiogenesis and inhibits tumor growth in hepatocellular carcinoma.

    PubMed

    Zhu, Li Ming; Shi, Dong Mei; Dai, Qiang; Cheng, Xiao Jiao; Yao, Wei Yan; Sun, Ping Hu; Ding, Yanfei; Qiao, Min Min; Wu, Yun Lin; Jiang, Shi Hu; Tu, Shui Ping

    2014-07-30

    X-linked inhibitor of apoptosis (XIAP)-associated factor 1 (XAF1), a XIAP-binding protein, is a tumor suppressor gene. XAF1 was silent or expressed lowly in most human malignant tumors. However, the role of XAF1 in hepatocellular carcinoma (HCC) remains unknown. In this study, we investigated the effect of XAF1 on tumor growth and angiogenesis in hepatocellular cancer cells. Our results showed that XAF1 expression was lower in HCC cell lines SMMC-7721, Hep G2 and BEL-7404 and liver cancer tissues than that in paired non-cancer liver tissues. Adenovirus-mediated XAF1 expression (Ad5/F35-XAF1) significantly inhibited cell proliferation and induced apoptosis in HCC cells in dose- and time- dependent manners. Infection of Ad5/F35-XAF1 induced cleavage of caspase -3, -8, -9 and PARP in HCC cells. Furthermore, Ad5/F35-XAF1 treatment significantly suppressed tumor growth in a xenograft model of liver cancer cells. Western Blot and immunohistochemistry staining showed that Ad5/F35-XAF1 treatment suppressed expression of vascular endothelial growth factor (VEGF), which is associated with tumor angiogenesis, in cancer cells and xenograft tumor tissues. Moreover, Ad5/F35-XAF1 treatment prolonged the survival of tumor-bearing mice. Our results demonstrate that XAF1 inhibits tumor growth by inducing apoptosis and inhibiting tumor angiogenesis. XAF1 may be a promising target for liver cancer treatment.

  17. Dihydroartiminisin inhibits the growth and metastasis of epithelial ovarian cancer.

    PubMed

    Wu, Buchu; Hu, Ke; Li, Shu; Zhu, Jing; Gu, Liying; Shen, Haoran; Hambly, Brett D; Bao, Shisan; Di, Wen

    2012-01-01

    Dihydroartiminisin (DHA), the active component of a Chinese herb (Artemisia annua), has been utilised as an anti-malarial drug since ancient China. DHA has also been shown to inhibit proliferation of cancer in vitro. However, the capacity of DHA to inhibit the development of ovarian cancer is still unclear. The adhesion, invasion, and migration of human ovarian cancer cell line (HO8910PM) was determined following DHA treatment in vitro, using Matrigel coated plate, transwell membrane chamber, and wound healing models, respectively. A mouse ovarian cancer model was established by orthotopic inoculation of HO8910PM cell line in nude mice. The growth and metastasis in vivo was determined 8 weeks post-implantation in response to DHA treatment. The expression of phosphorylated focal adhesion kinase (pFAK) and matrix metalloproteinases (MMP-2 and MMP-9) was evaluated using Western blotting. The expression of Von Willebrand factor (vWF) and infiltration of macrophages were determined, using immunohistochemistry. DHA inhibits ovarian cancer cell proliferation, adhesion, migration and invasion in vitro in a dose-dependent manner, consistent with decreased expression of pFAK and MMP-2, but not MMP-9. DHA inhibited metastasis significantly in vivo, associated with reduced vWF expression and macrophage infiltration. In conclusion, DHA inhibits the development of ovarian cancer, in part via down-regulating pFAK, MMP-2, vWF and macrophage infiltration. PMID:22025319

  18. Agriculture on Mars: Soils for Plant Growth

    NASA Technical Reports Server (NTRS)

    Ming, D. W.

    2016-01-01

    Robotic rovers and landers have enabled the mineralogical, chemical, and physical characterization of loose, unconsolidated materials on the surface of Mars. Planetary scientists refer to the regolith material as "soil." NASA is currently planning to send humans to Mars in the mid 2030s. Early missions may rely on the use of onsite resources to enable exploration and self-sufficient outposts on Mars. The martian "soil" and surface environment contain all essential plant growth elements. The study of martian surface materials and how they might react as agricultural soils opens a new frontier for researchers in the soil science community. Other potential applications for surface "soils" include (i) sources for extraction of essential plant-growth nutrients, (ii) sources of O2, H2, CO2, and H2O, (iii) substrates for microbial populations in the degradation of wastes, and (iv) shielding materials surrounding outpost structures to protect humans, plants, and microorganisms from radiation. There are many challenges that will have to be addressed by soil scientists prior to human exploration over the next two decades.

  19. Redox control of plant growth and development.

    PubMed

    Kocsy, Gábor; Tari, Irma; Vanková, Radomíra; Zechmann, Bernd; Gulyás, Zsolt; Poór, Péter; Galiba, Gábor

    2013-10-01

    Redox changes determined by genetic and environmental factors display well-organized interactions in the control of plant growth and development. Diurnal and seasonal changes in the environmental conditions are important for the normal course of these physiological processes and, similarly to their mild irregular alterations, for stress adaptation. However, fast or large-scale environmental changes may lead to damage or death of sensitive plants. The spatial and temporal redox changes influence growth and development due to the reprogramming of metabolism. In this process reactive oxygen and nitrogen species and antioxidants are involved as components of signalling networks. The control of growth, development and flowering by reactive oxygen and nitrogen species and antioxidants in interaction with hormones at organ, tissue, cellular and subcellular level will be discussed in the present review. Unsolved problems of the field, among others the need for identification of new components and interactions in the redox regulatory network at various organization levels using systems biology approaches will be also indicated.

  20. Honokiol inhibits the growth of head and neck squamous cell carcinoma by targeting epidermal growth factor receptor.

    PubMed

    Singh, Tripti; Gupta, Nirzari A; Xu, Su; Prasad, Ram; Velu, Sadanandan E; Katiyar, Santosh K

    2015-08-28

    Here, we report the chemotherapeutic effect of honokiol, a phytochemical from Magnolia plant, on human head and neck squamous cell carcinoma (HNSCC). Treatment of HNSCC cell lines from different sub-sites, SCC-1 (oral cavity), SCC-5 (larynx), OSC-19 (tongue) and FaDu (pharynx) with honokiol inhibited their cell viability, which was associated with the: (i) induction of apoptosis, (ii) correction of dysregulatory cell cycle proteins of G0/G1 phase. Honokiol decreased the expression levels of epidermal growth factor receptor (EGFR), mTOR and their downstream signaling molecules. Treatment of FaDu and SCC-1 cell lines with rapamycin, an inhibitor of mTOR pathway, also reduced cell viability of HNSCC cells. Administration of honokiol by oral gavage (100 mg/kg body weight) significantly (P < 0.01-0.001) inhibited the growth of SCC-1 and FaDu xenografts in athymic nude mice, which was associated with: (i) inhibition of tumor cell proliferation, (ii) induction of apoptosis, (iii) reduced expressions of cyclins and Cdks, and (iv) inhibition of EGFR signaling pathway. Molecular docking analysis of honokiol in EGFR binding site indicated that the chemotherapeutic effect of honokiol against HNSCC is mediated through its firm binding with EGFR, which is better than that of gefitinib, a commonly used drug for HNSCC treatment.

  1. Melatonin enhances plant growth and abiotic stress tolerance in soybean plants.

    PubMed

    Wei, Wei; Li, Qing-Tian; Chu, Ya-Nan; Reiter, Russel J; Yu, Xiao-Min; Zhu, Dan-Hua; Zhang, Wan-Ke; Ma, Biao; Lin, Qing; Zhang, Jin-Song; Chen, Shou-Yi

    2015-02-01

    Melatonin is a well-known agent that plays multiple roles in animals. Its possible function in plants is less clear. In the present study, we tested the effect of melatonin (N-acetyl-5-methoxytryptamine) on soybean growth and development. Coating seeds with melatonin significantly promoted soybean growth as judged from leaf size and plant height. This enhancement was also observed in soybean production and their fatty acid content. Melatonin increased pod number and seed number, but not 100-seed weight. Melatonin also improved soybean tolerance to salt and drought stresses. Transcriptome analysis revealed that salt stress inhibited expressions of genes related to binding, oxidoreductase activity/process, and secondary metabolic processes. Melatonin up-regulated expressions of the genes inhibited by salt stress, and hence alleviated the inhibitory effects of salt stress on gene expressions. Further detailed analysis of the affected pathways documents that melatonin probably achieved its promotional roles in soybean through enhancement of genes involved in cell division, photosynthesis, carbohydrate metabolism, fatty acid biosynthesis, and ascorbate metabolism. Our results demonstrate that melatonin has significant potential for improvement of soybean growth and seed production. Further study should uncover more about the molecular mechanisms of melatonin's function in soybeans and other crops.

  2. Melatonin enhances plant growth and abiotic stress tolerance in soybean plants.

    PubMed

    Wei, Wei; Li, Qing-Tian; Chu, Ya-Nan; Reiter, Russel J; Yu, Xiao-Min; Zhu, Dan-Hua; Zhang, Wan-Ke; Ma, Biao; Lin, Qing; Zhang, Jin-Song; Chen, Shou-Yi

    2015-02-01

    Melatonin is a well-known agent that plays multiple roles in animals. Its possible function in plants is less clear. In the present study, we tested the effect of melatonin (N-acetyl-5-methoxytryptamine) on soybean growth and development. Coating seeds with melatonin significantly promoted soybean growth as judged from leaf size and plant height. This enhancement was also observed in soybean production and their fatty acid content. Melatonin increased pod number and seed number, but not 100-seed weight. Melatonin also improved soybean tolerance to salt and drought stresses. Transcriptome analysis revealed that salt stress inhibited expressions of genes related to binding, oxidoreductase activity/process, and secondary metabolic processes. Melatonin up-regulated expressions of the genes inhibited by salt stress, and hence alleviated the inhibitory effects of salt stress on gene expressions. Further detailed analysis of the affected pathways documents that melatonin probably achieved its promotional roles in soybean through enhancement of genes involved in cell division, photosynthesis, carbohydrate metabolism, fatty acid biosynthesis, and ascorbate metabolism. Our results demonstrate that melatonin has significant potential for improvement of soybean growth and seed production. Further study should uncover more about the molecular mechanisms of melatonin's function in soybeans and other crops. PMID:25297548

  3. Melatonin enhances plant growth and abiotic stress tolerance in soybean plants

    PubMed Central

    Wei, Wei; Li, Qing-Tian; Chu, Ya-Nan; Reiter, Russel J.; Yu, Xiao-Min; Zhu, Dan-Hua; Zhang, Wan-Ke; Ma, Biao; Lin, Qing; Zhang, Jin-Song; Chen, Shou-Yi

    2015-01-01

    Melatonin is a well-known agent that plays multiple roles in animals. Its possible function in plants is less clear. In the present study, we tested the effect of melatonin (N-acetyl-5-methoxytryptamine) on soybean growth and development. Coating seeds with melatonin significantly promoted soybean growth as judged from leaf size and plant height. This enhancement was also observed in soybean production and their fatty acid content. Melatonin increased pod number and seed number, but not 100-seed weight. Melatonin also improved soybean tolerance to salt and drought stresses. Transcriptome analysis revealed that salt stress inhibited expressions of genes related to binding, oxidoreductase activity/process, and secondary metabolic processes. Melatonin up-regulated expressions of the genes inhibited by salt stress, and hence alleviated the inhibitory effects of salt stress on gene expressions. Further detailed analysis of the affected pathways documents that melatonin probably achieved its promotional roles in soybean through enhancement of genes involved in cell division, photosynthesis, carbohydrate metabolism, fatty acid biosynthesis, and ascorbate metabolism. Our results demonstrate that melatonin has significant potential for improvement of soybean growth and seed production. Further study should uncover more about the molecular mechanisms of melatonin’s function in soybeans and other crops. PMID:25297548

  4. Monoclonal Antibodies to Plant Growth Regulators

    PubMed Central

    Eberle, Joachim; Arnscheidt, Angelika; Klix, Dieter; Weiler, Elmar W.

    1986-01-01

    Four high affinity monoclonal antibodies, which recognize two plant growth regulators from the cytokinin group, namely trans-zeatin riboside and dihydrozeatin riboside and their derivatives are reported. Six hybridomas were produced from three independent fusions of Balb/c spleen cells with P3-NS1-Ag 4-1 (abbreviated NS1) or X63-Ag 8.653 (X63) myeloma cells. The mice had been hyperimmunized with zeatin riboside-bovine serum albumin conjugate or dihydrozeatin riboside-bovine serum albumin conjugate for 3 months. The hybridomas secrete antibodies of the IgG 1 or IgG 2b subclass and allow the detection of femtomole amounts of the free cytokinins, their ribosides, and ribotides in plant extracts. The use of these monoclonals in radio- and enzyme-linked immunosorbent assay is also discussed. PMID:16664848

  5. Anisotropic plant growth due to phototropism.

    PubMed

    Pietruszka, M; Lewicka, S

    2007-01-01

    Phototropism--the directional curvature of organs in response to lateral differences in light intensity and/or quality--represents one of the most rapid and visually obvious reaction of plants to changes in their light environment. It is a topic of fundamental interest to understand the mechanics of plants during growth. We propose a generalization of the scalar Lockhart model (1965) to three dimensional deformation, solve the new equation in two particular cases and compare results with empirical data. We believe that carefully designed experiments linked to our model will provide (by determining the active transport coefficient) a new method for qualitative description of auxin redistribution during phototropism. The proposed method supplements very recent investigations concerning specific auxin-influx and -efflux carriers (LAX and PIN proteins). PMID:17106746

  6. Gravitational effects on plant growth hormone concentration

    NASA Technical Reports Server (NTRS)

    Bandurski, R. S.; Schulze, A.

    1983-01-01

    Dolk's (1936) finding that more growth hormone diffuses from the lower side of a gravity-stimulated plant shoot than from the upper side is presently confirmed by means of both an isotope dilution assay and selected ion monitoring-gas chromatography-mass spectrometry, and it is established that the asymmetrically distributed hormone is indole-3-acetic acid (IAA). This is the first physicochemical demonstration that there is more IAA on the lower sides of a geostimulated plant shoot. It is also found that free IAA primarily occurs in the conductive vascular tissues of the shoot, while IAA esters predominate in the growing cortical cells. A highly sensitive gas chromatographic isotope dilution assay shows that the hormone asymmetry also occurs in the nonvascular tissue.

  7. Inhibition of plant fatty acid synthesis by nitroimidazoles.

    PubMed Central

    Jones, A V; Harwood, J L; Stratford, M R; Stumpf, P K

    1981-01-01

    1. The effect of the addition of a number of nitroimidazoles was tested on fatty acid synthesis by germinating pea seeds, isolated lettuce chloroplasts and a soluble fraction from pea seeds. 2. All the compounds tested had a marked inhibition on stearate desaturation by lettuce chloroplasts and on the synthesis of very-long-chain fatty acids by pea seeds. 3. In contrast, the effect of the drugs on total fatty acid synthesis from [14C]acetate in chloroplasts was related to the compound's electron reduction potentials. 4. Of the compounds used, only metronidazole had a marked inhibition on palmitate elongation in the systems tested. 5. The mechanism of inhibition of plant fatty acid synthesis by nitroimidazoles is discussed and the possible relevance of these findings to their neurotoxicity is suggested. PMID:7325993

  8. ATP level and caffeine efficiency on cytokinesis inhibition in plants.

    PubMed

    López-Sáez, J F; Mingo, R; González-Fernández, A

    1982-06-01

    Plant cytokinesis appears to be a topographically organized process of exocytosis. Golgi vesicles which contain cell wall precursors are translocated during telophase, by interzonal microtubules, to the equatorial region of the mitotic apparatus where they fuse with each other giving rise to the new cell wall. Caffeine inhibits cytokinesis by hindering Golgi vesicle coalescence. The present results demonstrate that treatments which increase the cellular ATP level (adenosine, cycloheximide and anisomycin) counteract caffein-induced cytokinesis inhibition in meristem cells of onion root tips (Allium cepa L.), while treatments which decrease ATP level potentiate this caffeine effect (dinitrophenol, fluoroacetate, low oxygen tensions, etc.). We postulate that caffeine, in competition with the cellular ATP level, blocks cell plate formation by inhibiting a certain ATPase activity required for membrane fusion of Golgi vesicles.

  9. Hormone activities and the cell cycle machinery in immunity-triggered growth inhibition

    PubMed Central

    Reitz, M. U.; Gifford, M. L.; Schäfer, P.

    2015-01-01

    Biotic stress and diseases caused by pathogen attack pose threats in crop production and significantly reduce crop yields. Enhancing immunity against pathogens is therefore of outstanding importance in crop breeding. However, this must be balanced, as immune activation inhibits plant growth. This immunity-coupled growth trade-off does not support resistance but is postulated to reflect the reallocation of resources to drive immunity. There is, however, increasing evidence that growth–immunity trade-offs are based on the reconfiguration of hormone pathways, shared by growth and immunity signalling. Studies in roots revealed the role of hormones in orchestrating growth across different cell types, with some hormones showing a defined cell type-specific activity. This is apparently highly relevant for the regulation of the cell cycle machinery and might be part of the growth–immunity cross-talk. Since plants are constantly exposed to Immuno-activating microbes under agricultural conditions, the transition from a growth to an immunity operating mode can significantly reduce crop yield and can conflict our efforts to generate next-generation crops with improved yield under climate change conditions. By focusing on roots, we outline the current knowledge of hormone signalling on the cell cycle machinery to explain growth trade-offs induced by immunity. By referring to abiotic stress studies, we further introduce how root cell type-specific hormone activities might contribute to growth under immunity and discuss the feasibility of uncoupling the growth–immunity cross-talk. PMID:25821072

  10. COI1, a jasmonate receptor, is involved in ethylene-induced inhibition of Arabidopsis root growth in the light.

    PubMed

    Adams, Eri; Turner, John

    2010-10-01

    Plant response to stress is orchestrated by hormone signalling pathways including those activated by jasmonates (JAs) and by ethylene, both of which stunt root growth. COI1 is a JA receptor and is required for the known responses to this hormone. It was observed that the coi1 mutant, which is largely unresponsive to growth inhibition by JAs, was also partially unresponsive to growth inhibition by ethylene and by its immediate precursor, 1-aminocyclopropane-1-carboxylic acid (ACC), in the light but not in the dark. Although COI1 was required for this response to ACC, other components of the JA signal perception pathway were not. Mutants selected for insensitivity to ethylene, including etr1, ein2, and ein3, showed greater ACC-induced root growth inhibition in the light than in the dark. However, the double mutants etr1;coi1, ein2;coi1, and ein3;coi1, and coi1 seedlings treated with silver ions to block the ethylene receptors showed almost complete unresponsiveness to ACC-induced root growth inhibition in the light. The light requirement for the COI1-mediated growth inhibition by ACC was for long photoperiods, and the ACC response was not abolished by mutations in the known photoreceptors. The complementation assay indicated that SCF complex assembly was not required for COI1 function in the ACC response, in contrast to the JA response. It is concluded that COI1 is required for the light-dependent, JA-independent, root growth inhibition by ethylene.

  11. Hydroxyapatite Growth Inhibition Effect of Pellicle Statherin Peptides.

    PubMed

    Xiao, Y; Karttunen, M; Jalkanen, J; Mussi, M C M; Liao, Y; Grohe, B; Lagugné-Labarthet, F; Siqueira, W L

    2015-08-01

    In our recent studies, we have shown that in vivo-acquired enamel pellicle is a sophisticated biological structure containing a significant portion of naturally occurring salivary peptides. From a functional aspect, the identification of peptides in the acquired enamel pellicle is of interest because many salivary proteins exhibit functional domains that maintain the activities of the native protein. Among the in vivo-acquired enamel pellicle peptides that have been newly identified, 5 peptides are derived from statherin. Here, we assessed the ability of these statherin pellicle peptides to inhibit hydroxyapatite crystal growth. In addition, atomistic molecular dynamics (MD) simulations were performed to better understand the underlying physical mechanisms of hydroxyapatite growth inhibition. A microplate colorimetric assay was used to quantify hydroxyapatite growth. Statherin protein, 5 statherin-derived peptides, and a peptide lacking phosphate at residues 2 and 3 were analyzed. Statherin peptide phosphorylated on residues 2 and 3 indicated a significant inhibitory effect when compared with the 5 other peptides (P < 0.05). MD simulations showed a strong affinity and fast adsorption to hydroxyapatite for phosphopeptides, whereas unphosphorylated peptides interacted weakly with the hydroxyapatite. Our data suggest that the presence of a covalently linked phosphate group (at residues 2 and 3) in statherin peptides modulates the effect of hydroxyapatite growth inhibition. This study provides a mechanism to account for the composition and function of acquired enamel pellicle statherin peptides that will contribute as a base for the development of biologically stable and functional synthetic peptides for therapeutic use against dental caries and/or periodontal disease.

  12. Hydroxyapatite Growth Inhibition Effect of Pellicle Statherin Peptides.

    PubMed

    Xiao, Y; Karttunen, M; Jalkanen, J; Mussi, M C M; Liao, Y; Grohe, B; Lagugné-Labarthet, F; Siqueira, W L

    2015-08-01

    In our recent studies, we have shown that in vivo-acquired enamel pellicle is a sophisticated biological structure containing a significant portion of naturally occurring salivary peptides. From a functional aspect, the identification of peptides in the acquired enamel pellicle is of interest because many salivary proteins exhibit functional domains that maintain the activities of the native protein. Among the in vivo-acquired enamel pellicle peptides that have been newly identified, 5 peptides are derived from statherin. Here, we assessed the ability of these statherin pellicle peptides to inhibit hydroxyapatite crystal growth. In addition, atomistic molecular dynamics (MD) simulations were performed to better understand the underlying physical mechanisms of hydroxyapatite growth inhibition. A microplate colorimetric assay was used to quantify hydroxyapatite growth. Statherin protein, 5 statherin-derived peptides, and a peptide lacking phosphate at residues 2 and 3 were analyzed. Statherin peptide phosphorylated on residues 2 and 3 indicated a significant inhibitory effect when compared with the 5 other peptides (P < 0.05). MD simulations showed a strong affinity and fast adsorption to hydroxyapatite for phosphopeptides, whereas unphosphorylated peptides interacted weakly with the hydroxyapatite. Our data suggest that the presence of a covalently linked phosphate group (at residues 2 and 3) in statherin peptides modulates the effect of hydroxyapatite growth inhibition. This study provides a mechanism to account for the composition and function of acquired enamel pellicle statherin peptides that will contribute as a base for the development of biologically stable and functional synthetic peptides for therapeutic use against dental caries and/or periodontal disease. PMID:26116492

  13. Silencing C19-GA 2-oxidases induces parthenocarpic development and inhibits lateral branching in tomato plants

    PubMed Central

    Martínez-Bello, Liliam; Moritz, Thomas; López-Díaz, Isabel

    2015-01-01

    Gibberellins (GAs) are phytohormones that regulate a wide range of developmental processes in plants. Levels of active GAs are regulated by biosynthetic and catabolic enzymes like the GA 2-oxidases (GA2oxs). In tomato (Solanum lycopersicum L.) C19 GA2oxs are encoded by a small multigenic family of five members with some degree of redundancy. In order to investigate their roles in tomato, the silencing of all five genes in transgenic plants was induced. A significant increase in active GA4 content was found in the ovaries of transgenic plants. In addition, the transgenic unfertilized ovaries were much bigger than wild-type ovaries (about 30 times) and a certain proportion (5–37%) were able to develop parthenocarpically. Among the GA2ox family, genes GA2ox1 and -2 seem to be the most relevant for this phenotype since their expression was induced in unfertilized ovaries and repressed in developing fruits, inversely correlating with ovary growth. Interestingly, transgenic lines exhibited a significant inhibition of branching and a higher content of active GA4 in axillary buds. This phenotype was reverted, in transgenic plants, by the application of paclobutrazol, a GA biosynthesis inhibitor, suggesting a role for GAs as repressors of branching. In summary, this work demonstrates that GA 2-oxidases regulate gibberellin levels in ovaries and axillary buds of tomato plants and their silencing is responsible for parthenocarpic fruit growth and branching inhibition. PMID:26093022

  14. Silencing C19-GA 2-oxidases induces parthenocarpic development and inhibits lateral branching in tomato plants.

    PubMed

    Martínez-Bello, Liliam; Moritz, Thomas; López-Díaz, Isabel

    2015-09-01

    Gibberellins (GAs) are phytohormones that regulate a wide range of developmental processes in plants. Levels of active GAs are regulated by biosynthetic and catabolic enzymes like the GA 2-oxidases (GA2oxs). In tomato (Solanum lycopersicum L.) C19 GA2oxs are encoded by a small multigenic family of five members with some degree of redundancy. In order to investigate their roles in tomato, the silencing of all five genes in transgenic plants was induced. A significant increase in active GA4 content was found in the ovaries of transgenic plants. In addition, the transgenic unfertilized ovaries were much bigger than wild-type ovaries (about 30 times) and a certain proportion (5-37%) were able to develop parthenocarpically. Among the GA2ox family, genes GA2ox1 and -2 seem to be the most relevant for this phenotype since their expression was induced in unfertilized ovaries and repressed in developing fruits, inversely correlating with ovary growth. Interestingly, transgenic lines exhibited a significant inhibition of branching and a higher content of active GA4 in axillary buds. This phenotype was reverted, in transgenic plants, by the application of paclobutrazol, a GA biosynthesis inhibitor, suggesting a role for GAs as repressors of branching. In summary, this work demonstrates that GA 2-oxidases regulate gibberellin levels in ovaries and axillary buds of tomato plants and their silencing is responsible for parthenocarpic fruit growth and branching inhibition. PMID:26093022

  15. Cell growth inhibition by sequence-specific RNA minihelices.

    PubMed Central

    Hipps, D; Schimmel, P

    1995-01-01

    RNA minihelices which reconstruct the 12 base pair acceptor-T psi C domains of transfer RNAs interact with their cognate tRNA synthetases. These substrates lack the anticodons of the genetic code and, therefore, cannot participate in steps of protein synthesis subsequent to aminoacylation. We report here that expression in Escherichia coli of either of two minihelices, each specific for a different amino acid, inhibited cell growth. Inhibition appears to be due to direct competition between the minihelix and its related tRNA for binding to their common synthetase. This competition, in turn, sharply lowers the pool of the specific charged tRNA for protein synthesis. Inhibition is relieved by single nucleotide changes which disrupt the minihelix-synthetase interaction. The results suggest that sequence-specific RNA minihelix substrates bind to cognate synthetases in vivo and can, in principle, act as cell growth regulators. Naturally occurring non-tRNA substrates for aminoacylation may serve a similar purpose. Images PMID:7664744

  16. Direct inhibition of Retinoblastoma phosphorylation by Nimbolide causes cell cycle arrest and suppresses glioblastoma growth

    PubMed Central

    Anderson, Jane; Liu, Xiaona; Henry, Heather; Gasilina, Anjelika; Nassar, Nicholas; Ghosh, Jayeeta; Clark, Jason P; Kumar, Ashish; Pauletti, Giovanni M.; Ghosh, Pradip K; Dasgupta, Biplab

    2013-01-01

    Purpose Classical pharmacology allows the use and development of conventional phytomedicine faster and more economically than conventional drugs. This approach should be tested for their efficacy in terms of complementarity and disease control. The purpose of this study was to determine the molecular mechanisms by which nimbolide, a triterpenoid found in the well-known medicinal plant Azadirachta indica controls glioblastoma (GBM) growth. Experimental Design Using in vitro signaling, anchorage-independent growth, kinase assays, and xenograft models, we investigated the mechanisms of its growth inhibition in glioblastoma. Results We show that nimbolide or an ethanol soluble fraction of A. indica leaves (Azt) that contains nimbolide as the principal cytotoxic agent is highly cytotoxic against GBM in vitro and in vivo. Azt caused cell cycle arrest, most prominently at the G1-S stage in GBM cells expressing EGFRvIII, an oncogene present in about 20-25% of GBMs. Azt/nimbolide directly inhibited CDK4/CDK6 kinase activity leading to hypophosphorylation of the retinoblastoma (RB) protein, cell cycle arrest at G1-S and cell death. Independent of RB hypophosphorylation, Azt also significantly reduced proliferative and survival advantage of GBM cells in vitro and in tumor xenografts by downregulating Bcl2 and blocking growth factor induced phosphorylation of Akt, Erk1/2 and STAT3. These effects were specific since Azt did not affect mTOR or other cell cycle regulators. In vivo, Azt completely prevented initiation and inhibited progression of GBM growth. Conclusions Our preclinical findings demonstrate Nimbolide as a potent anti-glioma agent that blocks cell cycle and inhibits glioma growth in vitro and in vivo. PMID:24170547

  17. A natural plant growth promoter calliterpenone from a plant Callicarpa macrophylla Vahl improves the plant growth promoting effects of plant growth promoting rhizobacteria (PGPRs).

    PubMed

    Maji, Deepamala; Barnawal, Deepti; Gupta, Aakansha; King, Shikha; Singh, A K; Kalra, A

    2013-05-01

    Experiments were conducted to evaluate the efficacy of calliterpenone, a natural plant growth promoter from a shrub Callicarpa macrophylla Vahl., in enhancing the growth and yield promoting effects of plant growth promoting rhizobacteria (PGPRs), in menthol mint (Mentha arvensis L).This study is based on our previous results indicating the microbial growth promotion by calliterpenone and assumption that application of calliterpenone along with PGPRs will improve the population of PGPRs resulting in higher impacts on plant growth and yield. Of the 15 PGPRs (identified as potent ones in our laboratory), 25 μl of 0.01 mM calliterpenone (8.0 μg/100 ml) was found to be useful in improving the population of nine PGPRs in culture media. The five selected strains of PGPRs exhibiting synergy with calliterpenone in enhancing growth of maize compared to PGPR or calliterpenone alone were selected and tested on two cultivars (cvs. Kosi and Kushal) of M. arvensis. Of the five strains, Bacillus subtilis P-20 (16S rDNA sequence homologous to Accession No NR027552) and B. subtilis Daz-26 (16SrDNA sequence homologuos to Accession No GU998816) were found to be highly effective in improving the herb and essential oil yield in the cultivars Kushal and Kosi respectively when co-treated with calliterpenone. The results open up the possibilities of using a natural growth promoter along with PGPRs as a bio-agri input for sustainable and organic agriculture.

  18. Pharmacologic inhibition of JAK-STAT signaling promotes hair growth.

    PubMed

    Harel, Sivan; Higgins, Claire A; Cerise, Jane E; Dai, Zhenpeng; Chen, James C; Clynes, Raphael; Christiano, Angela M

    2015-10-01

    Several forms of hair loss in humans are characterized by the inability of hair follicles to enter the growth phase (anagen) of the hair cycle after being arrested in the resting phase (telogen). Current pharmacologic therapies have been largely unsuccessful in targeting pathways that can be selectively modulated to induce entry into anagen. We show that topical treatment of mouse and human skin with small-molecule inhibitors of the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway results in rapid onset of anagen and subsequent hair growth. We show that JAK inhibition regulates the activation of key hair follicle populations such as the hair germ and improves the inductivity of cultured human dermal papilla cells by controlling a molecular signature enriched in intact, fully inductive dermal papillae. Our findings open new avenues for exploration of JAK-STAT inhibition for promotion of hair growth and highlight the role of this pathway in regulating the activation of hair follicle stem cells. PMID:26601320

  19. Pharmacologic inhibition of JAK-STAT signaling promotes hair growth

    PubMed Central

    Harel, Sivan; Higgins, Claire A.; Cerise, Jane E.; Dai, Zhenpeng; Chen, James C.; Clynes, Raphael; Christiano, Angela M.

    2015-01-01

    Several forms of hair loss in humans are characterized by the inability of hair follicles to enter the growth phase (anagen) of the hair cycle after being arrested in the resting phase (telogen). Current pharmacologic therapies have been largely unsuccessful in targeting pathways that can be selectively modulated to induce entry into anagen. We show that topical treatment of mouse and human skin with small-molecule inhibitors of the Janus kinase (JAK)–signal transducer and activator of transcription (STAT) pathway results in rapid onset of anagen and subsequent hair growth. We show that JAK inhibition regulates the activation of key hair follicle populations such as the hair germ and improves the inductivity of cultured human dermal papilla cells by controlling a molecular signature enriched in intact, fully inductive dermal papillae. Our findings open new avenues for exploration of JAK-STAT inhibition for promotion of hair growth and highlight the role of this pathway in regulating the activation of hair follicle stem cells. PMID:26601320

  20. [Growth inhibition effect of immobilized pectinase on Microcystis aeruginosa].

    PubMed

    Shen, Qing-Qing; Peng, Qian; Lai, Yong-Hong; Ji, Kai-Yan; Han, Xiu-Lin

    2012-12-01

    To confirm the growth inhibition effect of immobilized pectinase on algae, co-cultivation method was used to investigate the effect of immobilized pectinase on the growth of Microcystis aeruginosa. After co-cultivation, the damage status of the algae was observed through electron microscope, and the effect of immobilized pectase on the physiological and biochemical characteristics of the algae was also measured. The results showed that the algae and immobilized pectase co-cultivated solution etiolated distinctly on the third day and there was a significantly positive correlation between the extent of etiolation and the dosage as well as the treating time of the immobilized pectinase. Under electron microscope, plasmolysis was found in the slightly damaged cells, and the cell surface of these cells was rough, uneven and irregular; the severely damaged cells were collapsed or disintegrated completely. The algal yield and the chlorophyll a content decreased significantly with the increase of the treating time. The measurement of the malondiadehyde (MDA) value showed that the antioxidation system of the treated algal cells was destroyed, and their membrane lipid was severely peroxidated. The study indicated that the immobilized pectinase could efficiently inhibit the growth of M. aeruginosa, and the inhibitory rate reached up to 96%. PMID:23379158

  1. Pharmacologic inhibition of JAK-STAT signaling promotes hair growth.

    PubMed

    Harel, Sivan; Higgins, Claire A; Cerise, Jane E; Dai, Zhenpeng; Chen, James C; Clynes, Raphael; Christiano, Angela M

    2015-10-01

    Several forms of hair loss in humans are characterized by the inability of hair follicles to enter the growth phase (anagen) of the hair cycle after being arrested in the resting phase (telogen). Current pharmacologic therapies have been largely unsuccessful in targeting pathways that can be selectively modulated to induce entry into anagen. We show that topical treatment of mouse and human skin with small-molecule inhibitors of the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway results in rapid onset of anagen and subsequent hair growth. We show that JAK inhibition regulates the activation of key hair follicle populations such as the hair germ and improves the inductivity of cultured human dermal papilla cells by controlling a molecular signature enriched in intact, fully inductive dermal papillae. Our findings open new avenues for exploration of JAK-STAT inhibition for promotion of hair growth and highlight the role of this pathway in regulating the activation of hair follicle stem cells.

  2. Prolonged cyclic strain inhibits human endothelial cell growth.

    PubMed

    Peyton, Kelly J; Liu, Xiao-ming; Durante, William

    2016-01-01

    The vascular endothelium is continuously exposed to cyclic mechanical strain due to the periodic change in vessel diameter as a result of pulsatile blood flow. Since emerging evidence indicates the cyclic strain plays an integral role in regulating endothelial cell function, the present study determined whether application of a physiologic regimen of cyclic strain (6% at 1 hertz) influences the proliferation of human arterial endothelial cells. Prolonged exposure of human dermal microvascular or human aortic endothelial cells to cyclic strain for up to 7 days resulted in a marked decrease in cell growth. The strain-mediated anti-proliferative effect was associated with the arrest of endothelial cells in the G2/M phase of the cell cycle, did not involve cell detachment or cytotoxicity, and was due to the induction of p21. Interestingly, the inhibition in endothelial cell growth was independent of the strain regimen since prolonged application of constant or intermittent 6% strain was also able to block endothelial cell proliferation. The ability of chronic physiologic cyclic strain to inhibit endothelial cell growth represents a previously unrecognized mechanism by which hemodynamic forces maintain these cells in a quiescent, non-proliferative state. PMID:26709656

  3. Targeting Btk with ibrutinib inhibit gastric carcinoma cells growth

    PubMed Central

    Wang, Jin Dao; Chen, Xiao Ying; Ji, Ke Wei; Tao, Feng

    2016-01-01

    Bruton’s tyrosine kinase (Btk) is a member of the Tec-family non-receptor tyrosine kinases family. It has previously been reported to be expressed in B cells and has an important role in B-cell malignancies. While the roles of Btk in the pathogenesis of certain B-cell malignancies are well established, the functions of Btk in gastric carcinoma have never been investigated. Herein, we found that Btk is over-expressed in gastric carcinoma tissues and gastric cancer cells. Knockdown of Btk expression selectively inhibits the growth of gastric cancer cells, but not that of the normal gastric mucosa epithelial cell, which express very little Btk. Inhibition of Btk by its inhibitor ibrutinib has an additive inhibitory effect on gastric cancer cell growth. Treatment of gastric cancer cells, but not immortalized breast epithelial cells with ibrutinib results in effective cell killing, accompanied by the attenuation of Btk signals. Ibrutinib also induces apoptosis in gastric carcinoma cells as well as is a chemo-sensitizer for docetaxel (DTX), a standard of care for gastric carcinoma patients. Finally, ibrutinib markedly reduces tumor growth and increases tumor cell apoptosis in the tumors formed in mice inoculated with the gastric carcinoma cells. Given these promising preclinical results for ibrutinib in gastric carcinoma, a strategy combining Btk inhibitor warrants attention in gastric cancer. PMID:27508020

  4. Methyl anthranilate and γ-decalactone inhibit strawberry pathogen growth and achene Germination.

    PubMed

    Chambers, Alan H; Evans, Shane Alan; Folta, Kevin M

    2013-12-26

    Plant volatile compounds have been shown to affect microbial growth and seed germination. Here two fruity volatiles found in strawberry ( Fragaria × ananassa ), γ-decalactone ("peachlike" aroma) and methyl anthranilate ("grapelike" aroma), were tested for effects on relevant pathogens and seedling emergence. Significant growth reduction was observed for Botrytis cinerea , Colletotrichum gloeosporioides , Colletotrichum acutatum , Phomopsis obscurans , and Gnomonia fragariae at 1 mM γ-decalactone or methyl anthranilate, and 5 mM γ-decalactone or methyl anthranilate supplemented medium resulted in complete cessation of fungal growth. Phytophthora cactorum was especially sensitive to 1 mM γ-decalactone, showing complete growth inhibition. Bacteriostatic effects were observed in Xanthamonas cultures. Postharvest infestations on store-bought strawberries were inhibited with volatile treatment. The γ-decalactone volatile inhibited strawberry and Arabidopsis thaliana germination. These findings show that two compounds contributing to strawberry flavor may also contribute to shelf life and suggest that γ-decalactone may play an ecological role by preventing premature germination. PMID:24328200

  5. Mechanical forces in plant growth and development

    NASA Technical Reports Server (NTRS)

    Fisher, D. D.; Cyr, R. J.

    2000-01-01

    Plant cells perceive forces that arise from the environment and from the biophysics of plant growth. These forces provide meaningful cues that can affect the development of the plant. Seedlings of Arabidopsis thaliana were used to examine the cytoplasmic tensile character of cells that have been implicated in the gravitropic response. Laser-trapping technology revealed that the starch-containing statoliths of the central columella cells in root caps are held loosely within the cytoplasm. In contrast, the peripheral cells have starch granules that are relatively resistant to movement. The role of the actin cytoskeleton in affecting the tensile character of these cells is discussed. To explore the role that biophysical forces might play in generating developmental cues, we have developed an experimental model system in which protoplasts, embedded in a synthetic agarose matrix, are subjected to stretching or compression. We have found that protoplasts subjected to these forces from five minutes to two hours will subsequently elongate either at right angles or parallel to the tensive or compressive force vector. Moreover, the cortical microtubules are found to be organized either at right angles or parallel to the tensive or compressive force vector. We discuss these results in terms of an interplay of information between the extracellular matrix and the underlying cytoskeleton.

  6. Gravitational effects on plant growth hormone concentration

    NASA Astrophysics Data System (ADS)

    Bandurski, Robert S.; Schulze, Aga

    Numerous studies, particularly those of H. Dolk in the 1930's, established by means of bio-assay, that more growth hormone diffused from the lower, than from the upper side of a gravity-stimulated plant shoot. Now, using an isotope dilution assay, with 4,5,6,7 tetradeutero indole-3-acetic acid as internal standard, and selected ion monitoring-gas chromatography-mass spectrometry as the method of determination, we have confirmed Dolk's finding and established that the asymmetrically distributed hormone is, in fact, indole-3-acetic acid (IAA). This is the first physico-chemical demonstration that there is more free IAA on the lower sides of a geo-stimulated plant shoot. We have also shown that free IAA occurs primarily in the conductive vascular tissues of the shoot, whereas IAA esters predominate in the growing cortical cells. Now, using an especially sensitive gas chromatographic isotope dilution assay we have found that the hormone asymmetry also occurs in the non-vascular tissue. Currently, efforts are directed to developing isotope dilution assays, with picogram sensitivity, to determine how this asymmetry of IAA distribution is attained so as to better understand how the plant perceives the geo-stimulus.

  7. Instrumentation for plant health and growth.

    PubMed

    Schlager, K J

    1994-11-01

    Comprehensive spectroscopic monitoring of plant health and growth in bioregenerative life support system environments is possible using a variety of spectrometric technologies. Absorption spectrometry and atomic emission spectrometry in combination allow for direct, on-line, reagentless monitoring of plant nutrients from nitrate and potassium to micronutrients such as copper and zinc. Fluorometric spectrometry is ideal for the on-line detection, identification and quantification of bacteria and fungi. Liquid Atomic Emission Spectrometry (LAES) is a new form of spectrometry that allows for direct measurement of atomic emission spectra in liquids. An electric arc is generated by a pair of electrodes in the liquid to provide the energy necessary to break molecular bonds and reduce the substance to atomic form. With a fiber probe attached to the electrodes, spectral light can be transmitted to a photodiode array spectrometer for light dispersion and analysis. Ultraviolet (UV) absorption spectrometry is a long-established technology, but applications typically have required specific reagents to produce an analyte-specific absorption. Nitrate and iron nutrients have native UV absorption spectra that have been used to accurately determine nutrient concentrations at the +/- 5% level. Fluorescence detection and characterization of microbes is based upon the native fluorescent signatures of most microbiological species. Spectral and time-resolved fluorometers operating with remote fiber-optic probes will be used for on-line microbial monitoring in plant nutrient streams.

  8. Biomass Production System (BPS) Plant Growth Unit

    NASA Astrophysics Data System (ADS)

    Morrow, R. C.; Crabb, T. M.

    The Biomass Production System (BPS) was developed under the Small Business Innovative Research (SBIR) program to meet science, biotechnology and commercial plant growth needs in the Space Station era. The BPS is equivalent in size to a double middeck locker, but uses it's own custom enclosure with a slide out structure to which internal components mount. The BPS contains four internal growth chambers, each with a growing volume of more than 4 liters. Each of the growth chambers has active nutrient delivery, and independent control of temperature, humidity, lighting, and CO2 set-points. Temperature control is achieved using a thermoelectric heat exchanger system. Humidity control is achieved using a heat exchanger with a porous interface which can both humidify and dehumidify. The control software utilizes fuzzy logic for nonlinear, coupled temperature and humidity control. The fluorescent lighting system can be dimmed to provide a range of light levels. CO2 levels are controlled by injecting pure CO2 to the system based on input from an infrared gas analyzer. The unit currently does not scrub CO2, but has been designed to accept scrubber cartridges. In addition to providing environmental control, a number of features are included to facilitate science. The BPS chambers are sealed to allow CO2 and water vapor exchange measurements. The plant chambers can be removed to allow manipulation or sampling of specimens, and each chamber has gas/fluid sample ports. A video camera is provided for each chamber, and frame-grabs and complete environmental data for all science and hardware system sensors are stored on an internal hard drive. Data files can also be transferred to 3.5-inch disks using the front panel disk drive

  9. Biomass Production System (BPS) plant growth unit.

    PubMed

    Morrow, R C; Crabb, T M

    2000-01-01

    The Biomass Production System (BPS) was developed under the Small Business Innovative Research (SBIR) program to meet science, biotechnology and commercial plant growth needs in the Space Station era. The BPS is equivalent in size to a double middeck locker, but uses its own custom enclosure with a slide out structure to which internal components mount. The BPS contains four internal growth chambers, each with a growing volume of more than 4 liters. Each of the growth chambers has active nutrient delivery, and independent control of temperature, humidity, lighting, and CO2 set-points. Temperature control is achieved using a thermoelectric heat exchanger system. Humidity control is achieved using a heat exchanger with a porous interface which can both humidify and dehumidify. The control software utilizes fuzzy logic for nonlinear, coupled temperature and humidity control. The fluorescent lighting system can be dimmed to provide a range of light levels. CO2 levels are controlled by injecting pure CO2 to the system based on input from an infrared gas analyzer. The unit currently does not scrub CO2, but has been designed to accept scrubber cartridges. In addition to providing environmental control, a number of features are included to facilitate science. The BPS chambers are sealed to allow CO2 and water vapor exchange measurements. The plant chambers can be removed to allow manipulation or sampling of specimens, and each chamber has gas/fluid sample ports. A video camera is provided for each chamber, and frame-grabs and complete environmental data for all science and hardware system sensors are stored on an internal hard drive. Data files can also be transferred to 3.5-inch disks using the front panel disk drive. PMID:11543164

  10. Strigolactones are a new-defined class of plant hormones which inhibit shoot branching and mediate the interaction of plant-AM fungi and plant-parasitic weeds.

    PubMed

    Chen, Caiyan; Zou, Junhuang; Zhang, Shuying; Zaitlin, David; Zhu, Lihuang

    2009-08-01

    Because plants are sessile organisms, the ability to adapt to a wide range of environmental conditions is critical for their survival. As a consequence, plants use hormones to regulate growth, mitigate biotic and abiotic stresses, and to communicate with other organisms. Many plant hormones function pleiotropically in vivo, and often work in tandem with other hormones that are chemically distinct. A newly-defined class of plant hormones, the strigolactones, cooperate with auxins and cytokinins to control shoot branching and the outgrowth of lateral buds. Strigolactones were originally identified as compounds that stimulated the germination of parasitic plant seeds, and were also demonstrated to induce hyphal branching in arbuscular mycorrhizal (AM) fungi. AM fungi form symbioses with higher plant roots and mainly facilitate the absorption of phosphate from the soil. Conforming to the classical definition of a plant hormone, strigolactones are produced in the roots and translocated to the shoots where they inhibit shoot outgrowth and branching. The biosynthesis of this class of compounds is regulated by soil nutrient availability, i.e. the plant will increase its production of strigolactones when the soil phosphate concentration is limited, and decrease production when phosphates are in ample supply. Strigolactones that affect plant shoot branching, AM fungal hyphal branching, and seed germination in parasitic plants facilitate chemical synthesis of similar compounds to control these and other biological processes by exogenous application.

  11. Strigolactones are a new-defined class of plant hormones which inhibit shoot branching and mediate the interaction of plant-AM fungi and plant-parasitic weeds.

    PubMed

    Chen, Caiyan; Zou, Junhuang; Zhang, Shuying; Zaitlin, David; Zhu, Lihuang

    2009-08-01

    Because plants are sessile organisms, the ability to adapt to a wide range of environmental conditions is critical for their survival. As a consequence, plants use hormones to regulate growth, mitigate biotic and abiotic stresses, and to communicate with other organisms. Many plant hormones function pleiotropically in vivo, and often work in tandem with other hormones that are chemically distinct. A newly-defined class of plant hormones, the strigolactones, cooperate with auxins and cytokinins to control shoot branching and the outgrowth of lateral buds. Strigolactones were originally identified as compounds that stimulated the germination of parasitic plant seeds, and were also demonstrated to induce hyphal branching in arbuscular mycorrhizal (AM) fungi. AM fungi form symbioses with higher plant roots and mainly facilitate the absorption of phosphate from the soil. Conforming to the classical definition of a plant hormone, strigolactones are produced in the roots and translocated to the shoots where they inhibit shoot outgrowth and branching. The biosynthesis of this class of compounds is regulated by soil nutrient availability, i.e. the plant will increase its production of strigolactones when the soil phosphate concentration is limited, and decrease production when phosphates are in ample supply. Strigolactones that affect plant shoot branching, AM fungal hyphal branching, and seed germination in parasitic plants facilitate chemical synthesis of similar compounds to control these and other biological processes by exogenous application. PMID:19727586

  12. Eugenol-inhibited root growth in Avena fatua involves ROS-mediated oxidative damage.

    PubMed

    Ahuja, Nitina; Singh, Harminder Pal; Batish, Daizy Rani; Kohli, Ravinder Kumar

    2015-02-01

    Plant essential oils and their constituent monoterpenes are widely known plant growth retardants but their mechanism of action is not well understood. We explored the mechanism of phytotoxicity of eugenol, a monoterpenoid alcohol, proposed as a natural herbicide. Eugenol (100-1000 µM) retarded the germination of Avena fatua and strongly inhibited its root growth compared to the coleoptile growth. We further investigated the underlying physiological and biochemical alterations leading to the root growth inhibition. Eugenol induced the generation of reactive oxygen species (ROS) leading to oxidative stress and membrane damage in the root tissue. ROS generation measured in terms of hydrogen peroxide, superoxide anion and hydroxyl radical content increased significantly in the range of 24 to 144, 21 to 91, 46 to 173% over the control at 100 to 1000 µM eugenol, respectively. The disruption in membrane integrity was indicated by 25 to 125% increase in malondialdehyde (lipid peroxidation byproduct), and decreased conjugated diene content (~10 to 41%). The electrolyte leakage suggesting membrane damage increased both under light as well as dark conditions measured over a period from 0 to 30 h. In defense to the oxidative damage due to eugenol, a significant upregulation in the ROS-scavenging antioxidant enzyme machinery was observed. The activities of superoxide dismutases, catalases, ascorbate peroxidases, guaiacol peroxidases and glutathione reductases were elevated by ~1.5 to 2.8, 2 to 4.3, 1.9 to 5.0, 1.4 to 3.9, 2.5 to 5.5 times, respectively, in response to 100 to 1000 µM eugenol. The study concludes that eugenol inhibits early root growth through ROS-mediated oxidative damage, despite an activation of the antioxidant enzyme machinery.

  13. Piperlongumine inhibits lung tumor growth via inhibition of nuclear factor kappa B signaling pathway

    PubMed Central

    Zheng, Jie; Son, Dong Ju; Gu, Sun Mi; Woo, Ju Rang; Ham, Young Wan; Lee, Hee Pom; Kim, Wun Jae; Jung, Jae Kyung; Hong, Jin Tae

    2016-01-01

    Piperlongumine has anti-cancer activity in numerous cancer cell lines via various signaling pathways. But there has been no study regarding the mechanisms of PL on the lung cancer yet. Thus, we evaluated the anti-cancer effects and possible mechanisms of PL on non-small cell lung cancer (NSCLC) cells in vivo and in vitro. Our findings showed that PL induced apoptotic cell death and suppressed the DNA binding activity of NF-κB in a concentration dependent manner (0–15 μM) in NSCLC cells. Docking model and pull down assay showed that PL directly binds to the DNA binding site of nuclear factor-κB (NF-κB) p50 subunit, and surface plasmon resonance (SPR) analysis showed that PL binds to p50 concentration-dependently. Moreover, co-treatment of PL with NF-κB inhibitor phenylarsine oxide (0.1 μM) or p50 siRNA (100 nM) augmented PL-induced inhibitory effect on cell growth and activation of Fas and DR4. Notably, co-treatment of PL with p50 mutant plasmid (C62S) partially abolished PL-induced cell growth inhibition and decreased the enhanced expression of Fas and DR4. In xenograft mice model, PL (2.5–5 mg/kg) suppressed tumor growth of NSCLC dose-dependently. Therefore, these results indicated that PL could inhibit lung cancer cell growth via inhibition of NF-κB signaling pathway in vitro and in vivo. PMID:27198178

  14. Inhibition of Plant-Pathogenic Fungi by a Corn Trypsin Inhibitor Overexpressed in Escherichia coli

    PubMed Central

    Chen, Zhi-Yuan; Brown, Robert L.; Lax, Alan R.; Cleveland, Thomas E.; Russin, John S.

    1999-01-01

    The cDNA of a 14-kDa trypsin inhibitor (TI) from corn was subcloned into an Escherichia coli overexpression vector. The overexpressed TI was purified based on its insolubility in urea and then refolded into the active form in vitro. This recombinant TI inhibited both conidium germination and hyphal growth of all nine plant pathogenic fungi studied, including Aspergillus flavus, Aspergillus parasiticus, and Fusarium moniliforme. The calculated 50% inhibitory concentration of TI for conidium germination ranged from 70 to more than 300 μg/ml, and that for fungal growth ranged from 33 to 124 μg/ml depending on the fungal species. It also inhibited A. flavus and F. moniliforme simultaneously when they were tested together. The results suggest that the corn 14-kDa TI may function in host resistance against a variety of fungal pathogens of crops. PMID:10049901

  15. Plant Growth Under Light Emitting Diode Irradiation.

    NASA Astrophysics Data System (ADS)

    Tennessen, Daniel John

    Plant growth under light emitting diodes (LEDs) was investigated to determine if LEDs would be useful to provide radiant energy for two plant processes, photosynthesis and photomorphogenesis. Photosynthesis of tomato (Lycopersicon esculentum L.) and Kudzu (Pueraria lobata (Willd) Ohwi.) was measured using photons from LEDs to answer the following: (1) Are leaves able to use red LED light for photosynthesis? and (2) Is the efficiency of photosynthesis in pulsed light equal to that of continuous light? In 175 Pa CO _2, or in response to changes in CO _2,<=af photosynthesis and ATP status were the same in LED as in white xenon arc light. In 35 Pa CO_2, photosynthesis was 10% lower in LED than in xenon arc light due to lowered stomatal conductance. The quantum efficiency of photosynthesis in pulsed light was equal to continuous light, even when pulses were twice as bright as sunlight. Xanthophyll pigments were not affected by these bright pulses. Photomorphogenesis of tobacco (Nicotiana tabacum L.), tomato (Lycopersicon esculentum Mill.) and transformed tobacco and tomato (expressing oat phytochrome-A) was assessed by growing plants under red LED lamps in an attempt to answer the following: (1) What is the developmental response of non-transformed and transformed tobacco to red LED light? and (2) Can tomato plants that grow tall and spindly in red LED light be made to grow short by increasing the amount of phytochrome-A? The short phenotype of transformed tobacco was not evident when plants were grown in LED light. Addition of photons of far-red or blue light to red light resulted in short transformed tobacco. Tomato plants grew three times as tall and lacked leaf development in LED versus white light, but transformed tomato remained short and produced fruit under LED light. I have determined that the LED photons are useful for photosynthesis and that the photon efficiency of photosynthesis is the same in pulsed as in continuous light. From responses of tobacco, I

  16. Ammonia And Ethylene Optrodes For Research On Plant Growth

    NASA Technical Reports Server (NTRS)

    Zhou, Quan; Tabacco, Mary Beth

    1995-01-01

    Fiber-optic sensors developed for use in measuring concentrations of ammonia and ethylene near plants during experiments on growth of plants in enclosed environments. Developmental fiber-optic sensors satisfy need to measure concentrations as low as few parts per billion (ppb) and expected to contribute to research on roles of ethylene and ammonia in growth of plants.

  17. Targeting GIPC/Synectin in Pancreatic Cancer Inhibits Tumor Growth

    PubMed Central

    Muders, Michael H.; Vohra, Pawan K.; Dutta, Shamit K; Wang, Enfeng; Ikeda, Yasuhiro; Wang, Ling; Udugamasooriya, D. Gomika; Memic, Adnan; Rupashinghe, Chamila N.; Baretton, Gustavo B.; Aust, Daniela E.; Langer, Silke; Datta, Kaustubh; Simons, Michael; Spaller, Mark R.; Mukhopadhyay, Debabrata

    2009-01-01

    Translational Relevance The five year survival rate in patients with ductal adenocarcinoma of the pancreas is less than 4%. Accordingly, new targets for the treatment of this deadly disease are urgently needed. In this study, we show that targeting GAIP interacting protein C-terminal (GIPC, also known as Synectin) and its PDZ-domain reduces pancreatic cancer growth significantly in vitro and in vivo. Additionally, the blockage of GIPC/Synectin was accompanied by a reduction of IGF-1R protein levels. In summary, the use of a GIPC-PDZ domain inhibitor may be a viable option in the treatment of pancreatic adenocarcinoma in future. Purpose Various studies have demonstrated the importance of GAIP interacting protein, C-terminus (GIPC, also known as Synectin) as a central adaptor molecule in different signaling pathways and as an important mediator of receptor stability. GIPC/Synectin is associated with different growth promoting receptors like IGF-1R and integrins. These interactions were mediated through its PDZ domain. GIPC/Synectin has been shown to be overexpressed in pancreatic and breast cancer. The goal of this study was to demonstrate the importance of GIPC/Synectin in pancreatic cancer growth and to evaluate a possible therapeutic strategy by using a GIPC-PDZ domain inhibitor. Furthermore, the effect of targeting GIPC on the IGF-1 receptor as one of its associated receptors was tested. Experimental Design In vivo effects of GIPC/Synectin knockdown were studied after lentiviral transduction of luciferase-expressing pancreatic cancer cells with shRNA against GIPC/Synectin. Additionally, a GIPC-PDZ-targeting peptide was designed. This peptide was tested for its influence on pancreatic cancer growth in vitro and in vivo. Results Knockdown of GIPC/Synectin led to a significant inhibition of pancreatic adenocarcinoma growth in an orthotopic mouse model. Additionally, a cell-permeable GIPC-PDZ inhibitor was able to block tumor growth significantly without showing

  18. Effects of perchlorate on growth of four wetland plants and its accumulation in plant tissues.

    PubMed

    He, Hongzhi; Gao, Haishuo; Chen, Guikui; Li, Huashou; Lin, Hai; Shu, Zhenzhen

    2013-10-01

    Perchlorate contamination in water is of concern because of uncertainties about toxicity and health effects, impact on ecosystems, and possible indirect exposure pathways to humans. Therefore, it is very important to investigate the ecotoxicology of perchlorate and to screen plant species for phytoremediation. Effects of perchlorate (20, 200, and 500 mg/L) on the growth of four wetland plants (Eichhornia crassipes, Acorus calamus L., Thalia dealbata, and Canna indica) as well as its accumulation in different plant tissues were investigated through water culture experiments. Twenty milligrams per liter of perchlorate had no significant effects on height, root length, aboveground part weight, root weight, and oxidizing power of roots of four plants, except A. calamus, and increasing concentrations of perchlorate showed that out of the four wetland plants, only A. calamus had a significant (p<0.05) dose-dependent decrease in these parameters. When treated with 500 mg/L perchlorate, these parameters and chlorophyll content in the leaf of plants showed significant decline contrasted to control groups, except the root length of E. crassipes and C. indica. The order of inhibition rates of perchlorate on root length, aboveground part weight and root weight, and oxidizing power of roots was: A. calamus > C. indica > T. dealbata > E. crassipes and on chlorophyll content in the leaf it was: A. calamus > T. dealbata > C. indica > E. crassipes. The higher the concentration of perchlorate used, the higher the amount of perchlorate accumulation in plants. Perchlorate accumulation in aboveground tissues was much higher than that in underground tissues and leaf was the main tissue for perchlorate accumulation. The order of perchlorate accumulation content and the bioconcentration factor in leaf of four plants was: E. crassipes > C. indica > T. dealbata > A. calamus. Therefore, E. crassipes might be an ideal plant with high tolerance ability and accumulation ability for constructing

  19. Effects of perchlorate on growth of four wetland plants and its accumulation in plant tissues.

    PubMed

    He, Hongzhi; Gao, Haishuo; Chen, Guikui; Li, Huashou; Lin, Hai; Shu, Zhenzhen

    2013-10-01

    Perchlorate contamination in water is of concern because of uncertainties about toxicity and health effects, impact on ecosystems, and possible indirect exposure pathways to humans. Therefore, it is very important to investigate the ecotoxicology of perchlorate and to screen plant species for phytoremediation. Effects of perchlorate (20, 200, and 500 mg/L) on the growth of four wetland plants (Eichhornia crassipes, Acorus calamus L., Thalia dealbata, and Canna indica) as well as its accumulation in different plant tissues were investigated through water culture experiments. Twenty milligrams per liter of perchlorate had no significant effects on height, root length, aboveground part weight, root weight, and oxidizing power of roots of four plants, except A. calamus, and increasing concentrations of perchlorate showed that out of the four wetland plants, only A. calamus had a significant (p<0.05) dose-dependent decrease in these parameters. When treated with 500 mg/L perchlorate, these parameters and chlorophyll content in the leaf of plants showed significant decline contrasted to control groups, except the root length of E. crassipes and C. indica. The order of inhibition rates of perchlorate on root length, aboveground part weight and root weight, and oxidizing power of roots was: A. calamus > C. indica > T. dealbata > E. crassipes and on chlorophyll content in the leaf it was: A. calamus > T. dealbata > C. indica > E. crassipes. The higher the concentration of perchlorate used, the higher the amount of perchlorate accumulation in plants. Perchlorate accumulation in aboveground tissues was much higher than that in underground tissues and leaf was the main tissue for perchlorate accumulation. The order of perchlorate accumulation content and the bioconcentration factor in leaf of four plants was: E. crassipes > C. indica > T. dealbata > A. calamus. Therefore, E. crassipes might be an ideal plant with high tolerance ability and accumulation ability for constructing

  20. Genistein exposure inhibits growth and alters steroidogenesis in adult mouse antral follicles.

    PubMed

    Patel, Shreya; Peretz, Jackye; Pan, Yuan-Xiang; Helferich, William G; Flaws, Jodi A

    2016-02-15

    Genistein is a naturally occurring isoflavone phytoestrogen commonly found in plant products such as soybeans, lentils, and chickpeas. Genistein, like other phytoestrogens, has the potential to mimic, enhance, or impair the estradiol biosynthesis pathway, thereby potentially altering ovarian follicle growth. Previous studies have inconsistently indicated that genistein exposure may alter granulosa cell proliferation and hormone production, but no studies have examined the effects of genistein on intact antral follicles. Thus, this study was designed to test the hypothesis that genistein exposure inhibits follicle growth and steroidogenesis in intact antral follicles. To test this hypothesis, antral follicles isolated from CD-1 mice were cultured with vehicle (dimethyl sulfoxide; DMSO) or genistein (6.0 and 36μM) for 18-96h. Every 24h, follicle diameters were measured to assess growth. At the end of each culture period, the media were pooled to measure hormone levels, and the cultured follicles were collected to measure expression of cell cycle regulators and steroidogenic enzymes. The results indicate that genistein (36μM) inhibits growth of mouse antral follicles. Additionally, genistein (6.0 and 36μM) increases progesterone, testosterone, and dehydroepiandrosterone (DHEA) levels, but decreases estrone and estradiol levels. The results also indicate that genistein alters the expression of steroidogenic enzymes at 24, 72 and 96h, and the expression of cell cycle regulators at 18h. These data indicate that genistein exposure inhibits antral follicle growth by inhibiting the cell cycle, alters sex steroid hormone levels, and dysregulates steroidogenic enzymes in cultured mouse antral follicles. PMID:26792615

  1. Sulphadimethoxine inhibits Phaseolus vulgaris root growth and development of N-fixing nodules.

    PubMed

    Sartorius, Marilena; Riccio, Anna; Cermola, Michele; Casoria, Paolo; Patriarca, Eduardo J; Taté, Rosarita

    2009-07-01

    Sulphonamides contamination of cultivated lands occurs through the recurrent spreading of animal wastes from intensive farming. The aim of this study was to test the effect(s) of sulphadimethoxine on the beneficial N-fixing Rhizobium etli-Phaseolus vulgaris symbiosis under laboratory conditions. The consequence of increasing concentrations of sulphadimethoxine on the growth ability of free-living R. etli bacteria, as well as on seed germination, seedling development and growth of common bean plants was examined. We have established that sulphadimethoxine inhibited the growth of both symbiotic partners in a dose-dependent manner. Bacterial invasion occurring in developing root nodules was visualized by fluorescence microscopy generating EGFP-marked R. etli bacteria. Our results proved that the development of symbiotic N-fixing root nodules is hampered by sulphadimethoxine thus identifying sulphonamides as toxic compounds for the Rhizobium-legume symbiosis: a low-input sustainable agricultural practice.

  2. Erlotinib Inhibits Growth of a Patient-Derived Chordoma Xenograft

    PubMed Central

    Siu, I-Mei; Ruzevick, Jacob; Zhao, Qi; Connis, Nick; Jiao, Yuchen; Bettegowda, Chetan; Xia, Xuewei; Burger, Peter C.; Hann, Christine L.; Gallia, Gary L.

    2013-01-01

    Chordomas are rare primary bone tumors that occur along the neuraxis. Primary treatment is surgery, often followed by radiotherapy. Treatment options for patients with recurrence are limited and, notably, there are no FDA approved therapeutic agents. Development of therapeutic options has been limited by the paucity of preclinical model systems. We have established and previously reported the initial characterization of the first patient-derived chordoma xenograft model. In this study, we further characterize this model and demonstrate that it continues to resemble the original patient tumor histologically and immunohistochemically, maintains nuclear expression of brachyury, and is highly concordant with the original patient tumor by whole genome genotyping. Pathway analysis of this xenograft demonstrates activation of epidermal growth factor receptor (EGFR). In vitro studies demonstrate that two small molecule inhibitors of EGFR, erlotinib and gefitinib, inhibit proliferation of the chordoma cell line U-CH 1. We further demonstrate that erlotinib significantly inhibits chordoma growth in vivo. Evaluation of tumors post-treatment reveals that erlotinib reduces phosphorylation of EGFR. This is the first demonstration of antitumor activity in a patient-derived chordoma xenograft model and these findings support further evaluation of EGFR inhibitors in this disease. PMID:24260133

  3. Erlotinib inhibits growth of a patient-derived chordoma xenograft.

    PubMed

    Siu, I-Mei; Ruzevick, Jacob; Zhao, Qi; Connis, Nick; Jiao, Yuchen; Bettegowda, Chetan; Xia, Xuewei; Burger, Peter C; Hann, Christine L; Gallia, Gary L

    2013-01-01

    Chordomas are rare primary bone tumors that occur along the neuraxis. Primary treatment is surgery, often followed by radiotherapy. Treatment options for patients with recurrence are limited and, notably, there are no FDA approved therapeutic agents. Development of therapeutic options has been limited by the paucity of preclinical model systems. We have established and previously reported the initial characterization of the first patient-derived chordoma xenograft model. In this study, we further characterize this model and demonstrate that it continues to resemble the original patient tumor histologically and immunohistochemically, maintains nuclear expression of brachyury, and is highly concordant with the original patient tumor by whole genome genotyping. Pathway analysis of this xenograft demonstrates activation of epidermal growth factor receptor (EGFR). In vitro studies demonstrate that two small molecule inhibitors of EGFR, erlotinib and gefitinib, inhibit proliferation of the chordoma cell line U-CH 1. We further demonstrate that erlotinib significantly inhibits chordoma growth in vivo. Evaluation of tumors post-treatment reveals that erlotinib reduces phosphorylation of EGFR. This is the first demonstration of antitumor activity in a patient-derived chordoma xenograft model and these findings support further evaluation of EGFR inhibitors in this disease.

  4. Martian Soil Plant Growth Experiment: The Effects of Adding Nitrogen, Bacteria, and Fungi to Enhance Plant Growth

    NASA Technical Reports Server (NTRS)

    Kliman, D. M.; Cooper, J. B.; Anderson, R. C.

    2000-01-01

    Plant growth is enhanced by the presence of symbiotic soil microbes. In order to better understand how plants might prosper on Mars, we set up an experiment to test whether symbiotic microbes function to enhance plant growth in a Martian soil simulant.

  5. Strigolactones as mediators of plant growth responses to environmental conditions.

    PubMed

    Koltai, Hinanit; Kapulnik, Yoram

    2011-01-01

    Strigolactones (SLs) have been recently identified as a new group of plant hormones or their derivatives thereof, shown to play a role in plant development. Evolutionary forces have driven the development of mechanisms in plants that allow adaptive adjustments to a variety of different habitats by employing plasticity in shoot and root growth and development. The ability of SLs to regulate both shoot and root development suggests a role in the plant's response to its growth environment. To play this role, SL pathways need to be responsive to plant growth conditions, and affect plant growth toward increased adaptive adjustment. Here, the effects of SLs on shoot and root development are presented, and possible feedback loops between SLs and two environmental cues, light and nutrient status, are discussed; these might suggest a role for SLs in plants' adaptive adjustment to growth conditions.

  6. Calcium alleviates cadmium-induced inhibition on root growth by maintaining auxin homeostasis in Arabidopsis seedlings.

    PubMed

    Li, Ping; Zhao, Chengzhou; Zhang, Yongqiang; Wang, Xiaomin; Wang, Xiaoyu; Wang, Jianfeng; Wang, Feng; Bi, Yurong

    2016-01-01

    Cadmium (Cd) toxicity has been widely studied in different plant species. However, the mechanism involved in its toxicity and the cell response to Cd has not been well established. In the present study, we investigated the possible mechanism of calcium (Ca) in protecting Arabidopsis from Cd toxicity. The results showed that 50 μM Cd significantly inhibited the seedling growth and decreased the chlorophyll content in Arabidopsis. Specifically, the primary root (PR) length was decreased but the lateral root (LR) number was increased under Cd stress. Furthermore, Cd enhanced the hydrogen peroxide (H2O2) content and lipid peroxidation as indicated by malondialdehyde (MDA) accumulation. Cd also altered the level and the distribution of auxin in PR tips (as evidenced by DR5::GUS and PIN:GFP reporter expression) and the expression of several putative auxin biosynthetic, catabolic, and transport pathway-related genes. Application of 3 mM Ca alleviated the inhibition of Cd on the root growth. Ca application not only led to reducing oxidative injuries but also restoring the normal auxin transport and distribution in Arabidopsis root under Cd stress. Taken together, these results suggest that Ca alleviates the root growth inhibition caused by Cd through maintaining auxin homeostasis in Arabidopsis seedlings.

  7. Demonstrating the Effects of Light Quality on Plant Growth.

    ERIC Educational Resources Information Center

    Whitesell, J. H.; Garcia, Maria

    1977-01-01

    Describes a lab demonstration that illustrates the effect of different colors or wavelengths of visible light on plant growth and development. This demonstration is appropriate for use in college biology, botany, or plant physiology courses. (HM)

  8. Sugar signals and the control of plant growth and development.

    PubMed

    Lastdrager, Jeroen; Hanson, Johannes; Smeekens, Sjef

    2014-03-01

    Sugars have a central regulatory function in steering plant growth. This review focuses on information presented in the past 2 years on key players in sugar-mediated plant growth regulation, with emphasis on trehalose 6-phosphate, target of rapamycin kinase, and Snf1-related kinase 1 regulatory systems. The regulation of protein synthesis by sugars is fundamental to plant growth control, and recent advances in our understanding of the regulation of translation by sugars will be discussed.

  9. Plant-insect coevolution and inhibition of acetylcholinesterase.

    PubMed

    Ryan, M F; Byrne, O

    1988-10-01

    The theory of plant-insect coevolution provides for diffuse coevolution and the expectation that plants evolve broad-spectrum chemical defenses with which some insects coevolve by detoxifying and using the compounds as host-location cues. Specific biochemical modes of action have been assigned to relatively few such defense chemicals and one major class, the terpenoids, is investigated here. Six terpenoids inhibited the enzyme acetylcholinesterase (derived from electric eel) and elicited the appropriate in vivo effects of insect paralysis and mortality. The diterpene gossypol was a reversible uncompetitive inhibitor. Five monoterpenes, representing a range of functional groups, were reversible competitive inhibitors apparently occupying at least the hydrophobic site of the enzyme's active center. Such data suggest the involvement of acetylcholinesterase in the coevolved insect response to terpenoids.

  10. The flavonoid nobiletin inhibits tumor growth and angiogenesis of ovarian cancers via the Akt pathway.

    PubMed

    Chen, Jianchu; Chen, Allen Y; Huang, Haizhi; Ye, Xingqian; Rollyson, William D; Perry, Haley E; Brown, Kathleen C; Rojanasakul, Yon; Rankin, Gary O; Dasgupta, Piyali; Chen, Yi Charlie

    2015-01-01

    Despite its importance, the death rate of ovarian cancer has remained unchanged over the past five decades, demanding an improvement in prevention and treatment of this malignancy. With no known carcinogens, targeted prevention is currently unavailable, and efforts in early detection of this malignancy by screening biomarkers have failed. The inhibition of angiogenesis, also known as angioprevention, is a promising strategy to limit the growth of solid tumors, including ovarian cancers. Nobiletin, a polymethoxy flavonoid compound isolated from the tiansheng plant, has been shown to inhibit the growth of multiple types of human cancers. However, there are no reports involving the effect on nobiletin on human ovarian cancer. The present report shows that nobiletin potently decreases the viability of ovarian cancer cells in vitro. However, nobiletin does not affect the viability of normal ovarian epithelial cells at <40 µM. The antitumor activity of nobiletin was also observed in athymic mouse models and in chicken chorioallantoic membrane (CAM) models. The anti-neoplastic activity of nobiletin was due to its ability to inhibit angiogenesis. We also studied the molecular mechanisms by which nobiletin suppresses angiogenesis. We observed that nobiletin inhibits secretion of the key angiogenesis mediators, Akt, HIF-1α, NF-κB and vascular epithelial growth factor (VEGF) by ovarian cancer cells. Transient transfection experiments showed that nobiletin inhibits production of HIF-1α by downregulation of Akt. Such decreased levels of HIF-1α were responsible for nobiletin-induced suppression of VEGF. Our data suggest that nobiletin may be a promising anti-angiogenic agent relevant for therapy of ovarian cancers.

  11. The flavonoid nobiletin inhibits tumor growth and angiogenesis of ovarian cancers via the Akt pathway.

    PubMed

    Chen, Jianchu; Chen, Allen Y; Huang, Haizhi; Ye, Xingqian; Rollyson, William D; Perry, Haley E; Brown, Kathleen C; Rojanasakul, Yon; Rankin, Gary O; Dasgupta, Piyali; Chen, Yi Charlie

    2015-01-01

    Despite its importance, the death rate of ovarian cancer has remained unchanged over the past five decades, demanding an improvement in prevention and treatment of this malignancy. With no known carcinogens, targeted prevention is currently unavailable, and efforts in early detection of this malignancy by screening biomarkers have failed. The inhibition of angiogenesis, also known as angioprevention, is a promising strategy to limit the growth of solid tumors, including ovarian cancers. Nobiletin, a polymethoxy flavonoid compound isolated from the tiansheng plant, has been shown to inhibit the growth of multiple types of human cancers. However, there are no reports involving the effect on nobiletin on human ovarian cancer. The present report shows that nobiletin potently decreases the viability of ovarian cancer cells in vitro. However, nobiletin does not affect the viability of normal ovarian epithelial cells at <40 µM. The antitumor activity of nobiletin was also observed in athymic mouse models and in chicken chorioallantoic membrane (CAM) models. The anti-neoplastic activity of nobiletin was due to its ability to inhibit angiogenesis. We also studied the molecular mechanisms by which nobiletin suppresses angiogenesis. We observed that nobiletin inhibits secretion of the key angiogenesis mediators, Akt, HIF-1α, NF-κB and vascular epithelial growth factor (VEGF) by ovarian cancer cells. Transient transfection experiments showed that nobiletin inhibits production of HIF-1α by downregulation of Akt. Such decreased levels of HIF-1α were responsible for nobiletin-induced suppression of VEGF. Our data suggest that nobiletin may be a promising anti-angiogenic agent relevant for therapy of ovarian cancers. PMID:25845666

  12. Current status of plant products reported to inhibit sperm.

    PubMed

    Farnsworth, N R; Waller, D P

    1982-06-01

    This report reviews research on plant-derived agents that prevent sperm production if taken orally by the male or that incapacitate or kill sperm on contact if used vaginally by the female. It would be of great value to develop fertility inhibitors that are totally selective for reproductive systems and enzymes, and there is a possibility that a plant-derived drug may have this effect. Plants that have been studied for their fertility inhibiting effects in the male include: Aristolochia indica L. (Aristolochiaceae); Azadirachta indica A. Juss (Meliaceae); Balanites roxburghii Planch. (Zygophyllaceae); Calotropis procera (Ait) R.Br. (Asclepiadaceae); Carica papaya L. (Caricaceae); Catharanthus roseus (L.) G. Don (Apocynaceae); Dieffenbachia seguine (Jacquin) Schott. (Araceae); Ecaballium elaterium A. Richard (Cucurbitaceae); Gossypium species (Malvaceae); Hibiscus rosa-sinensis L. (Malvaceae); Hippophae salicifolia D. Don (Elaeagnaceae); Leucaena glauca (L.) Benth. (Leguminosae); Lonicera ciliosa Poir. (Caprifoliaceae); Lupinus termis Forsk. (Leguminosae); Malvaviscus conzattii Greenm. (Malvaceae); Momordica charantia L. (Curcurbitaceae); Ocimum sanctum L. (Labiatae); Prunus emarginata Walp. (Rosaceae); and Withania somnifera (L.) Dunal (Solanaceae). A large number of plants have been randomly selected and screened for spermicidal activity "in vitro" and several seem promising. Those species found to be active and the nature of the active principle(s), when known, are presented in a table as are plant-derived chemical substances of known or partially known structure reported to be spermicidal "in vitro." Plants warrant systematic study as potential sources of sperm-agglutinating compounds. Of 1600 Indian plants tested, 90 showed positive semen coagulating properties. There seems to be a lack of correlation among experimental results obtained by different groups of investigators, between data obtained "in vitro" and "in vivo," and between experimental results and

  13. Liver acid sphingomyelinase inhibits growth of metastatic colon cancer.

    PubMed

    Osawa, Yosuke; Suetsugu, Atsushi; Matsushima-Nishiwaki, Rie; Yasuda, Ichiro; Saibara, Toshiji; Moriwaki, Hisataka; Seishima, Mitsuru; Kozawa, Osamu

    2013-02-01

    Acid sphingomyelinase (ASM) regulates the homeostasis of sphingolipids, including ceramides and sphingosine-1-phosphate (S1P). These sphingolipids regulate carcinogenesis and proliferation, survival, and apoptosis of cancer cells. However, the role of ASM in host defense against liver metastasis remains unclear. In this study, the involvement of ASM in liver metastasis of colon cancer was examined using Asm-/- and Asm+/+ mice that were inoculated with SL4 colon cancer cells to produce metastatic liver tumors. Asm-/- mice demonstrated enhanced tumor growth and reduced macrophage accumulation in the tumor, accompanied by decreased numbers of hepatic myofibroblasts (hMFs), which express tissue inhibitor of metalloproteinase 1 (TIMP1), around the tumor margin. Tumor growth was increased by macrophage depletion or by Timp1 deficiency, but was decreased by hepatocyte-specific ASM overexpression, which was associated with increased S1P production. S1P stimulated macrophage migration and TIMP1 expression in hMFs in vitro. These findings indicate that ASM in the liver inhibits tumor growth through cytotoxic macrophage accumulation and TIMP1 production by hMFs in response to S1P. Targeting ASM may represent a new therapeutic strategy for treating liver metastasis of colon cancer.

  14. Inhibition of Glioblastoma Growth by the Thiadiazolidinone Compound TDZD-8

    PubMed Central

    Sanz-SanCristobal, Marina; Garcia-Cabezas, Miguel Angel; Santos, Angel; Perez-Castillo, Ana

    2010-01-01

    Background Thiadiazolidinones (TDZD) are small heterocyclic compounds first described as non-ATP competitive inhibitors of glycogen synthase kinase 3β (GSK-3β). In this study, we analyzed the effects of 4-benzyl-2-methyl-1,2,4-thiadiazolidine-3,5-dione (TDZD-8), on murine GL261 cells growth in vitro and on the growth of established intracerebral murine gliomas in vivo. Methodology/Principal Findings Our data show that TDZD-8 decreased proliferation and induced apoptosis of GL261 glioblastoma cells in vitro, delayed tumor growth in vivo, and augmented animal survival. These effects were associated with an early activation of extracellular signal-regulated kinase (ERK) pathway and increased expression of EGR-1 and p21 genes. Also, we observed a sustained activation of the ERK pathway, a concomitant phosphorylation and activation of ribosomal S6 kinase (p90RSK) and an inactivation of GSK-3β by phosphorylation at Ser 9. Finally, treatment of glioblastoma stem cells with TDZD-8 resulted in an inhibition of proliferation and self-renewal of these cells. Conclusions/Significance Our results suggest that TDZD-8 uses a novel mechanism to target glioblastoma cells, and that malignant progenitor population could be a target of this compound. PMID:21079728

  15. Improvement of plant growth and nickel uptake by nickel resistant-plant-growth promoting bacteria.

    PubMed

    Ma, Ying; Rajkumar, Mani; Freitas, Helena

    2009-07-30

    In this study, among a collection of Ni-resistant bacterial strains isolated from the rhizosphere of Alyssum serpyllifolium and Phleum phleoides grown on serpentine soil, five plant growth-promoting bacteria (PGPB) were selected based on their ability to utilize 1-aminocyclopropane-1-carboxylate (ACC) as the sole N source and promote seedling growth. All of the strains tested positive for indole-3-acetic acid (IAA) production and phosphate solubilization. In addition, four of the strains exhibited significant levels of siderophores production. Further, the efficiency of PGPB in enhancing Ni solubilization in soils was analyzed. Compared with control treatment, inoculation of PGPB strains significantly increased the concentrations of bioavailable Ni. Furthermore, a pot experiment was conducted to elucidate the effects of inoculating Ni-resistant PGPB on the plant growth and the uptake of Ni by Brassica juncea and B. oxyrrhina in soil contaminated with 450 mg kg(-1) Ni. Psychrobacter sp. SRA2 significantly increased the fresh (351%) and dry biomass (285%) of the B. juncea test plants (p<0.05), whereas Psychrobacter sp. SRA1 and Bacillus cereus SRA10 significantly increased the accumulation of Ni in the root and shoot tissues of B. juncea compared with non-inoculated controls. This result indicates that the strains SRA1 and SRA10 facilitated the release of Ni from the non-soluble phases in the soil, thus enhancing the availability of Ni to plants. A significant increase, greater than that of the control, was also noted for growth parameters of the B. oxyrrhina test plants when the seeds were treated with strain SRA2. This effect can be attributed to the utilization of ACC, solubilization of phosphate and production of IAA. The results of the study revealed that the inoculation of Ni mobilizing strains Psychrobacter sp. SRA1 and B. cereus SRA10 increases the efficiency of phytoextraction directly by enhancing the metal accumulation in plant tissues and the efficient

  16. Prevention of a plant disease by specific inhibition of fungal polyamine biosynthesis.

    PubMed Central

    Rajam, M V; Weinstein, L H; Galston, A W

    1985-01-01

    DL-alpha-Difluoromethylornithine (DFMO), an inhibitor of the polyamine biosynthetic enzyme ornithine decarboxylase (EC 4.1.1.17), strongly retards the growth of several species of phytopathogenic fungi in vitro. Such inhibition can be completely reversed by putrescine or spermidine, confirming the essentiality of polyamines for growth of fungal hyphae. We now show that DFMO can protect bean plants (Phaseolus vulgaris Linnaeus cv. Pinto) against infection by uredospores of the bean rust fungus, Uromyces phaseoli Linnaeus, race O. Unifoliolate leaves of 10-day-old greenhouse-grown seedlings were sprayed with 400 microliter per leaf of DFMO at various concentrations in 0.01% Tween 20 at pH 7.0 before or after inoculation with uredospores of Uromyces. After 16 hr in darkness in dew chambers to facilitate spore germination, plants were transferred to the greenhouse, arranged randomly, and examined for local lesions 7 days later. All concentrations of DFMO 0.50 mM or higher gave complete protection against the pathogen; at lower concentrations, postinoculation treatments with DFMO were generally more effective than preinoculation. The appearance of lesions on plants treated with lower concentrations of DFMO was retarded 2-6 days. DFMO also confers protection on unsprayed parts of treated plants, indicating the translocation of some protective effect from sprayed areas. DL-alpha-Difluoromethylarginine, an analogous inhibitor of arginine decarboxylase (EC 4.1.1.19), which is the rate-limiting enzyme in an alternative pathway for polyamine biosynthesis in higher plants, confers no protection even at 5 mM. This emphasizes ornithine decarboxylase as the biochemical locus of choice for the prevention of plant diseases by inhibiting polyamine metabolism. Images PMID:3931079

  17. Low temperature inhibits root growth by reducing auxin accumulation via ARR1/12.

    PubMed

    Zhu, Jiang; Zhang, Kun-Xiao; Wang, Wen-Shu; Gong, Wen; Liu, Wen-Cheng; Chen, Hong-Guo; Xu, Heng-Hao; Lu, Ying-Tang

    2015-04-01

    Plants exhibit reduced root growth when exposed to low temperature; however, how low temperature modulates root growth remains to be understood. Our study demonstrated that low temperature reduces both meristem size and cell number, repressing the division potential of meristematic cells by reducing auxin accumulation, possibly through the repressed expression of PIN1/3/7 and auxin biosynthesis-related genes, although the experiments with exogenous auxin application also suggest the involvement of other factor(s). In addition, we verified that ARABIDOPSIS RESPONSE REGULATOR 1 (ARR1) and ARR12 are involved in low temperature-mediated inhibition of root growth by showing that the roots of arr1-3 arr12-1 seedlings were less sensitive than wild-type roots to low temperature, in terms of changes in root length and meristem cell number. Furthermore, low temperature reduced the levels of PIN1/3 transcripts and the auxin level to a lesser extent in arr1-3 arr12-1 roots than in wild-type roots, suggesting that cytokinin signaling is involved in the low-temperature-mediated reduction of auxin accumulation. Taken together, our data suggest that low temperature inhibits root growth by reducing auxin accumulation via ARR1/12.

  18. Citrinolactones A, B and C, and Sclerotinin C, plant growth regulators from Penicillium citrinum.

    PubMed

    Kuramata, Masato; Fujioka, Shozo; Shimada, Atsumi; Kawano, Tsuyoshi; Kimura, Yasuo

    2007-02-01

    New plant growth regulators, named citrinolactones A (1), B (2) and C (3) and sclerotinin C (4), were isolated from Penicillium citrinum and their structures established by spectroscopic methods including 2D NMR. Compounds 1 and 4 increased root growth in proportion to their concentration from 3 to 300 mg/l. In contrast, 2 completely inhibited root growth at a concentration of 300 mg/l and 3 did not show any effect on root growth in a concentration range of 3-300 mg/l.

  19. Plant Growth Promotion Activity of Keratinolytic Fungi Growing on a Recalcitrant Waste Known as "Hair Waste".

    PubMed

    Cavello, Ivana A; Crespo, Juan M; García, Sabrina S; Zapiola, José M; Luna, María F; Cavalitto, Sebastián F

    2015-01-01

    Purpureocillium lilacinum (Thom) Samsom is one of the most studied fungi in the control of plant parasitic nematodes. However, there is not specific information on its ability to inhibit some pathogenic bacteria, fungi, or yeast. This work reports the production of several antifungal hydrolytic enzymes by a strain of P. lilacinum when it is grown in a medium containing hair waste. The growth of several plant-pathogenic fungi, Alternaria alternata, Aspergillus niger, and Fusarium culmorum, was considerably affected by the presence of P. lilacinum's supernatant. Besides antifungal activity, P. lilacinum demonstrates the capability to produce indoleacetic acid and ammonia during time cultivation on hair waste medium. Plant growth-promoting activity by cell-free supernatant was evidenced through the increase of the percentage of tomato seed germination from 71 to 85% after 48 hours. A 21-day plant growth assay using tomato plants indicates that crude supernatant promotes the growth of the plants similar to a reference fertilizer (p > 0.05). These results suggest that both strain and the supernatant may have potential to be considered as a potent biocontrol agent with multiple plant growth-promoting properties. To our knowledge, this is the first report on the antifungal, IAA production and tomato growth enhancing compounds produced by P. lilacinum LPSC #876.

  20. Plant Growth Promotion Activity of Keratinolytic Fungi Growing on a Recalcitrant Waste Known as "Hair Waste".

    PubMed

    Cavello, Ivana A; Crespo, Juan M; García, Sabrina S; Zapiola, José M; Luna, María F; Cavalitto, Sebastián F

    2015-01-01

    Purpureocillium lilacinum (Thom) Samsom is one of the most studied fungi in the control of plant parasitic nematodes. However, there is not specific information on its ability to inhibit some pathogenic bacteria, fungi, or yeast. This work reports the production of several antifungal hydrolytic enzymes by a strain of P. lilacinum when it is grown in a medium containing hair waste. The growth of several plant-pathogenic fungi, Alternaria alternata, Aspergillus niger, and Fusarium culmorum, was considerably affected by the presence of P. lilacinum's supernatant. Besides antifungal activity, P. lilacinum demonstrates the capability to produce indoleacetic acid and ammonia during time cultivation on hair waste medium. Plant growth-promoting activity by cell-free supernatant was evidenced through the increase of the percentage of tomato seed germination from 71 to 85% after 48 hours. A 21-day plant growth assay using tomato plants indicates that crude supernatant promotes the growth of the plants similar to a reference fertilizer (p > 0.05). These results suggest that both strain and the supernatant may have potential to be considered as a potent biocontrol agent with multiple plant growth-promoting properties. To our knowledge, this is the first report on the antifungal, IAA production and tomato growth enhancing compounds produced by P. lilacinum LPSC #876. PMID:26697226

  1. Curcumin associated magnetite nanoparticles inhibit in vitro melanoma cell growth.

    PubMed

    de Souza, Fernanda França; dos Santos, Michelly Christine; dos Passos, Debora Cristina Silva; Lima, Emilia Celma de Oliveira; Guillo, Lidia Andreu

    2011-09-01

    Curcumin is a natural product possessing therapeutic properties but the low water solubility of this compound limits its use. We have successfully incorporated curcumin into a bilayer of dodecanoic acid attached to magnetite nanoparticles in an effort to maximize solubility and delivery efficiency. Curcumin/magnetite nanoparticles were characterized using diffused reflectance infra-red fourier transform spectroscopy (DRIFTS) and X-ray powder diffraction (XRD). Moreover curcumin associated magnetite nanoparticles inhibited in vitro melanoma cell growth. An inhibitory concentration (IC50) of 66.0 +/- 3.0 microM (48 +/- 2.2 microg-iron/mL) was observed for the curcumin/magnetite nanoparticles. Fluorescent microscopy revealed that curcumin associated magnetite nanoparticles were internalized by the melanoma cells and remained in the cytoplasm. The curcumin/magnetic nanoparticles synthesized in this study possess magnetic and water solubility properties making this a novel curcumin formulation with therapeutic potential.

  2. Growth Signatures of Rosette Plants from Time-Lapse Video.

    PubMed

    Dellen, Babette; Scharr, Hanno; Torras, Carme

    2015-01-01

    Plant growth is a dynamic process, and the precise course of events during early plant development is of major interest for plant research. In this work, we investigate the growth of rosette plants by processing time-lapse videos of growing plants, where we use Nicotiana tabacum (tobacco) as a model plant. In each frame of the video sequences, potential leaves are detected using a leaf-shape model. These detections are prone to errors due to the complex shape of plants and their changing appearance in the image, depending on leaf movement, leaf growth, and illumination conditions. To cope with this problem, we employ a novel graph-based tracking algorithm which can bridge gaps in the sequence by linking leaf detections across a range of neighboring frames. We use the overlap of fitted leaf models as a pairwise similarity measure, and forbid graph edges that would link leaf detections within a single frame. We tested the method on a set of tobacco-plant growth sequences, and could track the first leaves of the plant, including partially or temporarily occluded ones, along complete sequences, demonstrating the applicability of the method to automatic plant growth analysis. All seedlings displayed approximately the same growth behavior, and a characteristic growth signature was found.

  3. Functional Characterization of Pseudomonas Contact Dependent Growth Inhibition (CDI) Systems

    PubMed Central

    Mercy, Chryslène; Ize, Bérengère; Salcedo, Suzana P.; de Bentzmann, Sophie; Bigot, Sarah

    2016-01-01

    Contact-dependent inhibition (CDI) toxins, delivered into the cytoplasm of target bacterial cells, confer to host strain a significant competitive advantage. Upon cell contact, the toxic C-terminal region of surface-exposed CdiA protein (CdiA-CT) inhibits the growth of CDI- bacteria. CDI+ cells express a specific immunity protein, CdiI, which protects from autoinhibition by blocking the activity of cognate CdiA-CT. CdiA-CT are separated from the rest of the protein by conserved peptide motifs falling into two distinct classes, the “E. coli”- and “Burkholderia-type”. CDI systems have been described in numerous species except in Pseudomonadaceae. In this study, we identified functional toxin/immunity genes linked to CDI systems in the Pseudomonas genus, which extend beyond the conventional CDI classes by the variability of the peptide motif that delimits the polymorphic CdiA-CT domain. Using P. aeruginosa PAO1 as a model, we identified the translational repressor RsmA as a negative regulator of CDI systems. Our data further suggest that under conditions of expression, P. aeruginosa CDI systems are implicated in adhesion and biofilm formation and provide an advantage in competition assays. All together our data imply that CDI systems could play an important role in niche adaptation of Pseudomonadaceae. PMID:26808644

  4. Nimbolide inhibits pancreatic cancer growth and metastasis through ROS-mediated apoptosis and inhibition of epithelial-to-mesenchymal transition.

    PubMed

    Subramani, Ramadevi; Gonzalez, Elizabeth; Arumugam, Arunkumar; Nandy, Sushmita; Gonzalez, Viviana; Medel, Joshua; Camacho, Fernando; Ortega, Andrew; Bonkoungou, Sandrine; Narayan, Mahesh; Dwivedi, Alok kumar; Lakshmanaswamy, Rajkumar

    2016-01-01

    The mortality and morbidity rates of pancreatic cancer are high because of its extremely invasive and metastatic nature. Its lack of symptoms, late diagnosis and chemo-resistance and the ineffective treatment modalities warrant the development of new chemo-therapeutic agents for pancreatic cancer. Agents from medicinal plants have demonstrated therapeutic benefits in various human cancers. Nimbolide, an active molecule isolated from Azadirachta indica, has been reported to exhibit several medicinal properties. This study assessed the anticancer properties of nimbolide against pancreatic cancer. Our data reveal that nimbolide induces excessive generation of reactive oxygen species (ROS), thereby regulating both apoptosis and autophagy in pancreatic cancer cells. Experiments with the autophagy inhibitors 3-methyladenine and chloroquine diphosphate salt and the apoptosis inhibitor z-VAD-fmk demonstrated that nimbolide-mediated ROS generation inhibited proliferation (through reduced PI3K/AKT/mTOR and ERK signaling) and metastasis (through decreased EMT, invasion, migration and colony forming abilities) via mitochondrial-mediated apoptotic cell death but not via autophagy. In vivo experiments also demonstrated that nimbolide was effective in inhibiting pancreatic cancer growth and metastasis. Overall, our data suggest that nimbolide can serve as a potential chemo-therapeutic agent for pancreatic cancer. PMID:26804739

  5. Plant growth promotion rhizobacteria in onion production.

    PubMed

    Colo, Josip; Hajnal-Jafari, Timea I; Durić, Simonida; Stamenov, Dragana; Hamidović, Saud

    2014-01-01

    The aim of the research was to examine the effect of rhizospheric bacteria Azotobacter chroococcum, Pseudomonas fluorescens (strains 1 and 2) and Bacillus subtilis on the growth and yield of onion and on the microorganisms in the rhizosphere of onion. The ability of microorganisms to produce indole-acetic acid (IAA), siderophores and to solubilize tricalcium phosphate (TCP) was also assessed. The experiment was conducted in field conditions, in chernozem type of soil. Bacillus subtilis was the best producer of IAA, whereas Pseudomonas fluorescens strains were better at producing siderophores and solubilizing phosphates. The longest seedling was observed with the application of Azotobacter chroococcum. The height of the plants sixty days after sowing was greater in all the inoculated variants than in the control. The highest onion yield was observed in Bacillus subtilis and Azotobacter chroococcum variants. The total number of bacteria and the number of Azotobacter chroococcum were larger in all the inoculated variants then in the control. The number of fungi decreased in most of the inoculated variants, whereas the number of actinomycetes decreased or remained the same. PMID:25033667

  6. A high-throughput imaging system to quantitatively analyze the growth dynamics of plant seedlings.

    PubMed

    Men, Yongfan; Yu, Qiang; Chen, Zitian; Wang, Jianbin; Huang, Yanyi; Guo, Hongwei

    2012-08-01

    Most current methods for analyzing the growth rate of plant seedlings are limited to low-throughput experimental configurations. We have developed an automatic system to investigate the dynamics of the growth of hypocotyls using Arabidopsis as model. This system is able to capture time-lapse infrared images of 24 seedlings automatically, with a spatial resolution of 2 μm per pixel and temporal interval of 5 min. Seedling length is rapidly calculated using automated geometric image-processing algorithms. With this high-throughput platform, we have investigated the genotype dependent difference of growth patterns, as well as the response to plant hormone - ethylene. Our analyses suggest that cytoskeleton function is not required in ethylene-induced hypocotyl inhibition. This novel integrative method can be applied to large-scale dynamic screening of plants, as well as any other image-based biological studies related to dynamic growth.

  7. Kaempferol inhibits Entamoeba histolytica growth by altering cytoskeletal functions.

    PubMed

    Bolaños, Verónica; Díaz-Martínez, Alfredo; Soto, Jacqueline; Marchat, Laurence A; Sanchez-Monroy, Virginia; Ramírez-Moreno, Esther

    2015-11-01

    The flavonoid kaempferol obtained from Helianthemum glomeratum, an endemic Mexican medicinal herb used to treat gastrointestinal disorders, has been shown to inhibit growth of Entamoeba histolytica trophozoites in vitro; however, the mechanisms associated with this activity have not been documented. Several works reported that kaempferol affects cytoskeleton in mammalian cells. In order to gain insights into the action mechanisms involved in the anti-amoebic effect of kaempferol, here we evaluated the effect of this compound on the pathogenic events driven by the cytoskeleton during E. histolytica infection. We also carried out a two dimensional gel-based proteomic analysis to evidence modulated proteins that could explain the phenotypical changes observed in trophozoites. Our results showed that kaempferol produces a dose-dependent effect on trophozoites growth and viability with optimal concentration being 27.7 μM. Kaempferol also decreased adhesion, it increased migration and phagocytic activity, but it did not affect erythrocyte binding nor cytolytic capacity of E. histolytica. Congruently, proteomic analysis revealed that the cytoskeleton proteins actin, myosin II heavy chain and cortexillin II were up-regulated in response to kaempferol treatment. In conclusion, kaempferol anti-amoebic effects were associated with deregulation of proteins related with cytoskeleton, which altered invasion mechanisms.

  8. ABCB5-Targeted Chemoresistance Reversal Inhibits Merkel Cell Carcinoma Growth.

    PubMed

    Kleffel, Sonja; Lee, Nayoung; Lezcano, Cecilia; Wilson, Brian J; Sobolewski, Kristine; Saab, Karim R; Mueller, Hansgeorg; Zhan, Qian; Posch, Christian; Elco, Christopher P; DoRosario, Andrew; Garcia, Sarah S; Thakuria, Manisha; Wang, Yaoyu E; Wang, Linda C; Murphy, George F; Frank, Markus H; Schatton, Tobias

    2016-04-01

    Merkel cell carcinoma (MCC) is a highly aggressive neuroendocrine skin cancer with profound but poorly understood resistance to chemotherapy, which poses a significant barrier to clinical MCC treatment. Here we show that ATP-binding cassette member B5 (ABCB5) confers resistance to standard-of-care MCC chemotherapeutic agents and provide proof-of-principle that ABCB5 blockade can inhibit human MCC tumor growth through sensitization to drug-induced cell cytotoxicity. ABCB5 expression was detected in both established MCC lines and clinical MCC specimens at levels significantly higher than those in normal skin. Carboplatin- and etoposide-resistant MCC cell lines exhibited increased expression of ABCB5, along with enhanced ABCB1 and ABCC3 transcript expression. ABCB5-expressing MCC cells in heterogeneous cancers preferentially survived treatment with carboplatin and etoposide in vitro and in human MCC xenograft-bearing mice in vivo. Moreover, patients with MCC also exhibited enhanced ABCB5 positivity after carboplatin- and etoposide-based chemotherapy, pointing to clinical significance of this chemoresistance mechanism. Importantly, ABCB5 blockade reversed MCC drug resistance and impaired tumor growth in xenotransplantation models in vivo. Our results establish ABCB5 as a chemoresistance mechanism in MCC and suggest utility of this molecular target for improved MCC therapy. PMID:26827764

  9. The research on Virtual Plants Growth Based on DLA Model

    NASA Astrophysics Data System (ADS)

    Zou, YunLan; Chai, Bencheng

    This article summarizes the separated Evolutionary Algorithm in fractal algorithm of Diffusion Limited Aggregation model (i.e. DLA model) and put forward the virtual plant growth realization in computer based on DLA model. The method is carried out in the VB6.0 environment to achieve and verify the plant growth based on DLA model.

  10. Growth inhibition by tungsten in the sulfur-oxidizing bacterium Acidithiobacillus thiooxidans.

    PubMed

    Negishi, Atsunori; Muraoka, Tadashi; Maeda, Terunobu; Takeuchi, Fumiaki; Kanao, Tadayoshi; Kamimura, Kazuo; Sugio, Tsuyoshi

    2005-11-01

    Growth of five strains of sulfur-oxidizing bacteria Acidithiobacillus thiooxidans, including strain NB1-3, was inhibited completely by 50 microM of sodium tungstate (Na(2)WO(4)). When the cells of NB1-3 were incubated in 0.1 M beta-alanine-SO(4)(2-) buffer (pH 3.0) with 100 microM Na(2)WO(4) for 1 h, the amount of tungsten bound to the cells was 33 microg/mg protein. Approximately 10 times more tungsten was bound to the cells at pH 3.0 than at pH 7.0. The tungsten binding to NB1-3 cells was inhibited by oxyanions such as sodium molybdenum and ammonium vanadate. The activities of enzymes involved in elemental sulfur oxidation of NB1-3 cells such as sulfur oxidase, sulfur dioxygenase, and sulfite oxidase were strongly inhibited by Na(2)WO(4). These results indicate that tungsten binds to NB1-3 cells and inhibits the sulfur oxidation enzyme system of the cells, and as a result, inhibits cell growth. When portland cement bars supplemented with 0.075% metal nickel and with 0.075% metal nickel and 0.075% calcium tungstate were exposed to the atmosphere of a sewage treatment plant containing 28 ppm of H(2)S for 2 years, the weight loss of the portland cement bar with metal nickel and calcium tungstate was much lower than the cement bar containing 0.075% metal nickel.

  11. Growth inhibition of Erwinia amylovora and related Erwinia species by neutralized short‑chain fatty acids.

    PubMed

    Konecki, Katrin; Gernold, Marina; Wensing, Annette; Geider, Klaus

    2013-11-01

    Short-chain fatty acids (SCFAs) are used to preserve food and could be a tool for control of fire blight caused by Erwinia amylovora on apple, pear and related rosaceous plants. Neutralized acids were added to buffered growth media at 0.5–75 mM and tested at pHs ranging from 6.8 to 5.5. Particularly at low pH, SCFAs with a chain length exceeding that of acetic acid such as propionic acid were effective growth inhibitors of E. amylovora possibly due to uptake of free acid and its intracellular accumulation. We also observed high inhibition with monochloroacetic acid. An E. billingiae strain was as sensitive to the acids as E. amylovora or E. tasmaniensis. Fire blight symptoms on pear slices were reduced when the slices were pretreated with neutralized propionic acid. Propionic acid is well water soluble and could be applied in orchards as a control agent for fire blight.

  12. Complete genome sequence of the rapeseed plant-growth promoting Serratia plymuthica strain AS9

    SciTech Connect

    Neupane, Saraswoti; Hogberg, Nils; Alstrom, Sadhna; Lucas, Susan; Han, James; Lapidus, Alla L.; Cheng, Jan-Fang; Bruce, David; Goodwin, Lynne A.; Pitluck, Sam; Peters, Lin; Ovchinnikova, Galina; Lu, Megan; Han, Cliff; Detter, J. Chris; Tapia, Roxanne; Fiebig, Anne; Land, Miriam L; Hauser, Loren John; Kyrpides, Nikos C; Ivanova, N; Pagani, Ioanna; Klenk, Hans-Peter; Woyke, Tanja; Finlay, Roger D.

    2012-01-01

    Serratia plymuthica are plant-associated, plant beneficial species belonging to the family Enterobacteriaceae. The members of the genus Serratia are ubiquitous in nature and their life style varies from endophytic to free-living. S. plymuthica AS9 is of special interest for its ability to inhibit fungal pathogens of rapeseed and to promote plant growth. The genome of S. plymuthica AS9 comprises a 5,442,880 bp long circular chromosome that consists of 4,952 protein-coding genes, 87 tRNA genes and 7 rRNA operons. This genome is part of the project entitled Genomics of four rapeseed plant growth promoting bacteria with antagonistic effect on plant pathogens awarded through the 2010 DOE-JGI Community Sequencing Program (CSP2010).

  13. Complete genome sequence of the rapeseed plant-growth promoting Serratia plymuthica strain AS9

    PubMed Central

    Högberg, Nils; Alström, Sadhna; Lucas, Susan; Han, James; Lapidus, Alla; Cheng, Jan-Fang; Bruce, David; Goodwin, Lynne; Pitluck, Sam; Peters, Lin; Ovchinnikova, Galina; Lu, Megan; Han, Cliff; Detter, John C.; Tapia, Roxanne; Fiebig, Anne; Land, Miriam; Hauser, Loren; Kyrpides, Nikos C.; Ivanova, Natalia; Pagani, Ioanna; Klenk, Hans-Peter; Woyke, Tanja; Finlay, Roger D.

    2012-01-01

    Serratia plymuthica are plant-associated, plant beneficial species belonging to the family Enterobacteriaceae. The members of the genus Serratia are ubiquitous in nature and their life style varies from endophytic to free-living. S. plymuthica AS9 is of special interest for its ability to inhibit fungal pathogens of rapeseed and to promote plant growth. The genome of S. plymuthica AS9 comprises a 5,442,880 bp long circular chromosome that consists of 4,952 protein-coding genes, 87 tRNA genes and 7 rRNA operons. This genome is part of the project entitled “Genomics of four rapeseed plant growth promoting bacteria with antagonistic effect on plant pathogens” awarded through the 2010 DOE-JGI Community Sequencing Program (CSP2010). PMID:22675598

  14. The regulation of plant growth by the circadian clock.

    PubMed

    Farré, E M

    2012-05-01

    Circadian regulated changes in growth rates have been observed in numerous plants as well as in unicellular and multicellular algae. The circadian clock regulates a multitude of factors that affect growth in plants, such as water and carbon availability and light and hormone signalling pathways. The combination of high-resolution growth rate analyses with mutant and biochemical analysis is helping us elucidate the time-dependent interactions between these factors and discover the molecular mechanisms involved. At the molecular level, growth in plants is modulated through a complex regulatory network, in which the circadian clock acts at multiple levels.

  15. Plant growth-promoting bacteria as inoculants in agricultural soils.

    PubMed

    Souza, Rocheli de; Ambrosini, Adriana; Passaglia, Luciane M P

    2015-12-01

    Plant-microbe interactions in the rhizosphere are the determinants of plant health, productivity and soil fertility. Plant growth-promoting bacteria (PGPB) are bacteria that can enhance plant growth and protect plants from disease and abiotic stresses through a wide variety of mechanisms; those that establish close associations with plants, such as the endophytes, could be more successful in plant growth promotion. Several important bacterial characteristics, such as biological nitrogen fixation, phosphate solubilization, ACC deaminase activity, and production of siderophores and phytohormones, can be assessed as plant growth promotion (PGP) traits. Bacterial inoculants can contribute to increase agronomic efficiency by reducing production costs and environmental pollution, once the use of chemical fertilizers can be reduced or eliminated if the inoculants are efficient. For bacterial inoculants to obtain success in improving plant growth and productivity, several processes involved can influence the efficiency of inoculation, as for example the exudation by plant roots, the bacterial colonization in the roots, and soil health. This review presents an overview of the importance of soil-plant-microbe interactions to the development of efficient inoculants, once PGPB are extensively studied microorganisms, representing a very diverse group of easily accessible beneficial bacteria.

  16. Plant growth-promoting bacteria as inoculants in agricultural soils

    PubMed Central

    de Souza, Rocheli; Ambrosini, Adriana; Passaglia, Luciane M.P.

    2015-01-01

    Abstract Plant-microbe interactions in the rhizosphere are the determinants of plant health, productivity and soil fertility. Plant growth-promoting bacteria (PGPB) are bacteria that can enhance plant growth and protect plants from disease and abiotic stresses through a wide variety of mechanisms; those that establish close associations with plants, such as the endophytes, could be more successful in plant growth promotion. Several important bacterial characteristics, such as biological nitrogen fixation, phosphate solubilization, ACC deaminase activity, and production of siderophores and phytohormones, can be assessed as plant growth promotion (PGP) traits. Bacterial inoculants can contribute to increase agronomic efficiency by reducing production costs and environmental pollution, once the use of chemical fertilizers can be reduced or eliminated if the inoculants are efficient. For bacterial inoculants to obtain success in improving plant growth and productivity, several processes involved can influence the efficiency of inoculation, as for example the exudation by plant roots, the bacterial colonization in the roots, and soil health. This review presents an overview of the importance of soil-plant-microbe interactions to the development of efficient inoculants, once PGPB are extensively studied microorganisms, representing a very diverse group of easily accessible beneficial bacteria. PMID:26537605

  17. Mobile phone radiation inhibits Vigna radiata (mung bean) root growth by inducing oxidative stress.

    PubMed

    Sharma, Ved Parkash; Singh, Harminder Pal; Kohli, Ravinder Kumar; Batish, Daizy Rani

    2009-10-15

    During the last couple of decades, there has been a tremendous increase in the use of cell phones. It has significantly added to the rapidly increasing EMF smog, an unprecedented type of pollution consisting of radiation in the environment, thereby prompting the scientists to study the effects on humans. However, not many studies have been conducted to explore the effects of cell phone EMFr on growth and biochemical changes in plants. We investigated whether EMFr from cell phones inhibit growth of Vigna radiata (mung bean) through induction of conventional stress responses. Effects of cell phone EMFr (power density: 8.55 microW cm(-2); 900 MHz band width; for 1/2, 1, 2, and 4 h) were determined by measuring the generation of reactive oxygen species (ROS) in terms of malondialdehyde and hydrogen peroxide (H(2)O(2)) content, root oxidizability and changes in levels of antioxidant enzymes. Our results showed that cell phone EMFr significantly inhibited the germination (at > or =2 h), and radicle and plumule growths (> or =1 h) in mung bean in a time-dependent manner. Further, cell phone EMFr enhanced MDA content (indicating lipid peroxidation), and increased H(2)O(2) accumulation and root oxidizability in mung bean roots, thereby inducing oxidative stress and cellular damage. In response to EMFr, there was a significant upregulation in the activities of scavenging enzymes, such as superoxide dismutases, ascorbate peroxidases, guaiacol peroxidases, catalases and glutathione reductases, in mung bean roots. The study concluded that cell phone EMFr inhibit root growth of mung bean by inducing ROS-generated oxidative stress despite increased activities of antioxidant enzymes.

  18. Herbal extracts of Tribulus terrestris and Bergenia ligulata inhibit growth of calcium oxalate monohydrate crystals in vitro

    NASA Astrophysics Data System (ADS)

    Joshi, V. S.; Parekh, B. B.; Joshi, M. J.; Vaidya, A. B.

    2005-02-01

    A large number of people in this world are suffering from urinary stone problem. Calcium oxalate monohydrate (COM) and calcium oxalate dihydrate (COD) containing stones (calculi) are commonly found. In the present study, COM crystals were grown by a double diffusion gel growth technique using U-tubes. The gel was prepared from hydrated sodium metasilicate solution. The gel framework acts like a three-dimensional crucible in which the crystal nuclei are delicately held in the position of their formation, and nutrients are supplied for the growth. This technique can be utilized as a simplified screening static model to study the growth, inhibition and dissolution of urinary stones in vitro. The action of putative litholytic medicinal plants, Tribulus terrestris Linn. ( T.t) and Bergenia ligulata Linn. ( B.l.), has been studied in the growth of COM crystals. Tribulus terrestris and Bergenia ligulata are commonly used as herbal medicines for urinary calculi in India. To verify the inhibitive effect, aqueous extracts of Tribulus terrestris and Bergenia ligulata were added along with the supernatant solutions. The growth was measured and compared, with and without the aqueous extracts. Inhibition of COM crystal growth was observed in the herbal extracts. Maximum inhibition was observed in Bergenia ligulata followed by Tribulus terrestris. The results are discussed.

  19. Bioprospecting glacial ice for plant growth promoting bacteria.

    PubMed

    Balcazar, Wilvis; Rondón, Johnma; Rengifo, Marcos; Ball, María M; Melfo, Alejandra; Gómez, Wileidy; Yarzábal, Luis Andrés

    2015-08-01

    Glaciers harbor a wide diversity of microorganisms, metabolically versatile, highly tolerant to multiple environmental stresses and potentially useful for biotechnological purposes. Among these, we hypothesized the presence of bacteria able to exhibit well-known plant growth promoting traits (PGP). These kinds of bacteria have been employed for the development of commercial biofertilizers; unfortunately, these biotechnological products have proven ineffective in colder climates, like the ones prevailing in mountainous ecosystems. In the present work, we prospected glacial ice collected from two small tropical glaciers, located above 4.900 m in the Venezuelan Andes, for cold-active PGP bacteria. The initial screening strategy allowed us to detect the best inorganic-P solubilizers at low temperatures, from a sub-sample of 50 bacterial isolates. Solubilization of tricalcium phosphate, aluminum- and iron-phosphate, occurred in liquid cultures at low temperatures and was dependent on medium acidification by gluconic acid production, when bacteria were supplied with an appropriate source of carbon. Besides, the isolates were psychrophilic and in some cases exhibited a broad range of growth-temperatures, from 4 °C to 30 °C. Additional PGP abilities, including phytohormone- and HCN production, siderophore excretion and inhibition of phytopathogens, were confirmed in vitro. Nucleotidic sequence analysis of 16S rRNA genes allowed us to place the isolates within the Pseudomonas genus. Our results support the possible use of these strains to develop cold-active biofertilizers to be used in mountainous agriculture.

  20. Versatile roles of plastids in plant growth and development.

    PubMed

    Inaba, Takehito; Ito-Inaba, Yasuko

    2010-11-01

    Plastids, found in plants and some parasites, are of endosymbiotic origin. The best-characterized plastid is the plant cell chloroplast. Plastids provide essential metabolic and signaling functions, such as the photosynthetic process in chloroplasts. However, the role of plastids is not limited to production of metabolites. Plastids affect numerous aspects of plant growth and development through biogenesis, varying functional states and metabolic activities. Examples include, but are not limited to, embryogenesis, leaf development, gravitropism, temperature response and plant-microbe interactions. In this review, we summarize the versatile roles of plastids in plant growth and development.

  1. Growth inhibition by selenium is associated with changes in primary metabolism and nutrient levels in Arabidopsis thaliana.

    PubMed

    Ribeiro, Dimas M; Silva Júnior, Dalton D; Cardoso, Flávio Barcellos; Martins, Auxiliadora O; Silva, Welder A; Nascimento, Vitor L; Araújo, Wagner L

    2016-10-01

    Although Selenium (Se) stress is relatively well known for causing growth inhibition, its effects on primary metabolism remain rather unclear. Here, we characterized both the modulation of the expression of specific genes and the metabolic adjustments in Arabidopsis thaliana in response to changes in Se level in the soil. Se treatment culminated with strong inhibition of both shoot and root growth. Notably, growth inhibition in Se-treated plants was associated with an incomplete mobilization of starch during the night. Minor changes in amino acids levels were observed in shoots and roots of plants treated with Se whereas the pool size of tricarboxylic acid (TCA) cycle intermediates in root was not altered in response to Se. By contrast, decreased levels of organic acids involved in the first part of the TCA cycle were observed in shoots of Se-treated plants. Furthermore, decreased expression levels of expansins and endotransglucosylases/endohydrolases (XHTs) genes were observed after Se treatment, coupled with a significant decrease in the levels of essential elements. Collectively, our results revealed an exquisite interaction between energy metabolism and Se-mediated control of growth in Arabidopsis thaliana to coordinate cell wall extension, starch turnover and the levels of a few essential nutrients. PMID:27342381

  2. Plant growth promotion in cereal and leguminous agricultural important plants: from microorganism capacities to crop production.

    PubMed

    Pérez-Montaño, F; Alías-Villegas, C; Bellogín, R A; del Cerro, P; Espuny, M R; Jiménez-Guerrero, I; López-Baena, F J; Ollero, F J; Cubo, T

    2014-01-01

    Plant growth-promoting rhizobacteria (PGPR) are free-living bacteria which actively colonize plant roots, exerting beneficial effects on plant development. The PGPR may (i) promote the plant growth either by using their own metabolism (solubilizing phosphates, producing hormones or fixing nitrogen) or directly affecting the plant metabolism (increasing the uptake of water and minerals), enhancing root development, increasing the enzymatic activity of the plant or "helping" other beneficial microorganisms to enhance their action on the plants; (ii) or may promote the plant growth by suppressing plant pathogens. These abilities are of great agriculture importance in terms of improving soil fertility and crop yield, thus reducing the negative impact of chemical fertilizers on the environment. The progress in the last decade in using PGPR in a variety of plants (maize, rice, wheat, soybean and bean) along with their mechanism of action are summarized and discussed here.

  3. Plant growth promotion in cereal and leguminous agricultural important plants: from microorganism capacities to crop production.

    PubMed

    Pérez-Montaño, F; Alías-Villegas, C; Bellogín, R A; del Cerro, P; Espuny, M R; Jiménez-Guerrero, I; López-Baena, F J; Ollero, F J; Cubo, T

    2014-01-01

    Plant growth-promoting rhizobacteria (PGPR) are free-living bacteria which actively colonize plant roots, exerting beneficial effects on plant development. The PGPR may (i) promote the plant growth either by using their own metabolism (solubilizing phosphates, producing hormones or fixing nitrogen) or directly affecting the plant metabolism (increasing the uptake of water and minerals), enhancing root development, increasing the enzymatic activity of the plant or "helping" other beneficial microorganisms to enhance their action on the plants; (ii) or may promote the plant growth by suppressing plant pathogens. These abilities are of great agriculture importance in terms of improving soil fertility and crop yield, thus reducing the negative impact of chemical fertilizers on the environment. The progress in the last decade in using PGPR in a variety of plants (maize, rice, wheat, soybean and bean) along with their mechanism of action are summarized and discussed here. PMID:24144612

  4. Ratite oils promote keratinocyte cell growth and inhibit leukocyte activation

    PubMed Central

    Bennett, Darin C.; Leung, Gigi; Wang, Eddy; Ma, Sam; Lo, Blanche K. K.; McElwee, Kevin J.; Cheng, Kimberly M.

    2015-01-01

    Traditionally, native Australian aborigines have used emu oil for the treatment of inflammation and to accelerate wound healing. Studies on mice suggest that topically applied emu oil may have anti-inflammatory properties and may promote wound healing. We investigated the effects of ratite oils (6 emu, 3 ostrich, 1 rhea) on immortalized human keratinocytes (HaCaT cells) in vitro by culturing the cells in media with oil concentrations of 0%, 0.5%, and 1.0%. Peking duck, tea tree, and olive oils were used as comparative controls. The same oils at 0.5% concentration were evaluated for their influence on peripheral blood mononuclear cell (PBMC) survival over 48 hr and their ability to inhibit IFNγ production in PBMCs activated by phytohemagglutinin (PHA) in ELISpot assays. Compared to no oil control, significantly shorter population doubling time durations were observed for HaCaT cells cultured in emu oil (1.51 × faster), ostrich oil (1.46 × faster), and rhea oil (1.64 × faster). Tea tree oil demonstrated significant antiproliferative activity and olive oil significantly prolonged (1.35 × slower) cell population doubling time. In contrast, almost all oils, particularly tea tree oil, significantly reduced PBMC viability. Different oils had different levels of inhibitory effect on IFNγ production with individual emu, ostrich, rhea, and duck oil samples conferring full inhibition. This preliminary investigation suggests that emu oil might promote wound healing by accelerating the growth rate of keratinocytes. Combined with anti-inflammatory properties, ratite oil may serve as a useful component in bandages and ointments for the treatment of wounds and inflammatory skin conditions. PMID:26217022

  5. Ratite oils promote keratinocyte cell growth and inhibit leukocyte activation.

    PubMed

    Bennett, Darin C; Leung, Gigi; Wang, Eddy; Ma, Sam; Lo, Blanche K K; McElwee, Kevin J; Cheng, Kimberly M

    2015-09-01

    Traditionally, native Australian aborigines have used emu oil for the treatment of inflammation and to accelerate wound healing. Studies on mice suggest that topically applied emu oil may have anti-inflammatory properties and may promote wound healing. We investigated the effects of ratite oils (6 emu, 3 ostrich, 1 rhea) on immortalized human keratinocytes (HaCaT cells) in vitro by culturing the cells in media with oil concentrations of 0%, 0.5%, and 1.0%. Peking duck, tea tree, and olive oils were used as comparative controls. The same oils at 0.5% concentration were evaluated for their influence on peripheral blood mononuclear cell (PBMC) survival over 48 hr and their ability to inhibit IFNγ production in PBMCs activated by phytohemagglutinin (PHA) in ELISpot assays. Compared to no oil control, significantly shorter population doubling time durations were observed for HaCaT cells cultured in emu oil (1.51×faster), ostrich oil (1.46×faster), and rhea oil (1.64×faster). Tea tree oil demonstrated significant antiproliferative activity and olive oil significantly prolonged (1.35×slower) cell population doubling time. In contrast, almost all oils, particularly tea tree oil, significantly reduced PBMC viability. Different oils had different levels of inhibitory effect on IFNγ production with individual emu, ostrich, rhea, and duck oil samples conferring full inhibition. This preliminary investigation suggests that emu oil might promote wound healing by accelerating the growth rate of keratinocytes. Combined with anti-inflammatory properties, ratite oil may serve as a useful component in bandages and ointments for the treatment of wounds and inflammatory skin conditions. PMID:26217022

  6. Repression of Growth Regulating Factors by the MicroRNA396 Inhibits Cell Proliferation by UV-B Radiation in Arabidopsis Leaves[C][W

    PubMed Central

    Casadevall, Romina; Rodriguez, Ramiro E.; Debernardi, Juan M.; Palatnik, Javier F.; Casati, Paula

    2013-01-01

    Because of their sessile lifestyle, plants are continuously exposed to solar UV-B radiation. Inhibition of leaf growth is one of the most consistent responses of plants upon exposure to UV-B radiation. In this work, we investigated the role of GROWTH-REGULATING FACTORs (GRFs) and of microRNA miR396 in UV-B–mediated inhibition of leaf growth in Arabidopsis thaliana plants. We demonstrate that miRNA396 is upregulated by UV-B radiation in proliferating tissues and that this induction is correlated with a decrease in GRF1, GRF2, and GRF3 transcripts. Induction of miR396 results in inhibition of cell proliferation, and this outcome is independent of the UV-B photoreceptor UV resistance locus 8, as well as ATM AND RAD3–RELATED and the mitogen-activated protein kinase MPK6, but is dependent on MPK3. Transgenic plants expressing an artificial target mimic directed against miR396 (MIM396) with a decrease in the endogenous microRNA activity or plants expressing miR396-resistant copies of several GRFs are less sensitive to this inhibition. Consequently, at intensities that can induce DNA damage in Arabidopsis plants, UV-B radiation limits leaf growth by inhibiting cell division in proliferating tissues, a process mediated by miR396 and GRFs. PMID:24076976

  7. Plants Release Precursors of Histone Deacetylase Inhibitors to Suppress Growth of Competitors.

    PubMed

    Venturelli, Sascha; Belz, Regina G; Kämper, Andreas; Berger, Alexander; von Horn, Kyra; Wegner, André; Böcker, Alexander; Zabulon, Gérald; Langenecker, Tobias; Kohlbacher, Oliver; Barneche, Fredy; Weigel, Detlef; Lauer, Ulrich M; Bitzer, Michael; Becker, Claude

    2015-11-01

    To secure their access to water, light, and nutrients, many plant species have developed allelopathic strategies to suppress competitors. To this end, they release into the rhizosphere phytotoxic substances that inhibit the germination and growth of neighbors. Despite the importance of allelopathy in shaping natural plant communities and for agricultural production, the underlying molecular mechanisms are largely unknown. Here, we report that allelochemicals derived from the common class of cyclic hydroxamic acid root exudates directly affect the chromatin-modifying machinery in Arabidopsis thaliana. These allelochemicals inhibit histone deacetylases both in vitro and in vivo and exert their activity through locus-specific alterations of histone acetylation and associated gene expression. Our multilevel analysis collectively shows how plant-plant interactions interfere with a fundamental cellular process, histone acetylation, by targeting an evolutionarily highly conserved class of enzymes.

  8. Plants Release Precursors of Histone Deacetylase Inhibitors to Suppress Growth of Competitors.

    PubMed

    Venturelli, Sascha; Belz, Regina G; Kämper, Andreas; Berger, Alexander; von Horn, Kyra; Wegner, André; Böcker, Alexander; Zabulon, Gérald; Langenecker, Tobias; Kohlbacher, Oliver; Barneche, Fredy; Weigel, Detlef; Lauer, Ulrich M; Bitzer, Michael; Becker, Claude

    2015-11-01

    To secure their access to water, light, and nutrients, many plant species have developed allelopathic strategies to suppress competitors. To this end, they release into the rhizosphere phytotoxic substances that inhibit the germination and growth of neighbors. Despite the importance of allelopathy in shaping natural plant communities and for agricultural production, the underlying molecular mechanisms are largely unknown. Here, we report that allelochemicals derived from the common class of cyclic hydroxamic acid root exudates directly affect the chromatin-modifying machinery in Arabidopsis thaliana. These allelochemicals inhibit histone deacetylases both in vitro and in vivo and exert their activity through locus-specific alterations of histone acetylation and associated gene expression. Our multilevel analysis collectively shows how plant-plant interactions interfere with a fundamental cellular process, histone acetylation, by targeting an evolutionarily highly conserved class of enzymes. PMID:26530086

  9. Plants Release Precursors of Histone Deacetylase Inhibitors to Suppress Growth of Competitors[OPEN

    PubMed Central

    Venturelli, Sascha; Belz, Regina G.; Kämper, Andreas; Berger, Alexander; von Horn, Kyra; Wegner, André; Böcker, Alexander; Zabulon, Gérald; Barneche, Fredy; Lauer, Ulrich M.; Bitzer, Michael

    2015-01-01

    To secure their access to water, light, and nutrients, many plant species have developed allelopathic strategies to suppress competitors. To this end, they release into the rhizosphere phytotoxic substances that inhibit the germination and growth of neighbors. Despite the importance of allelopathy in shaping natural plant communities and for agricultural production, the underlying molecular mechanisms are largely unknown. Here, we report that allelochemicals derived from the common class of cyclic hydroxamic acid root exudates directly affect the chromatin-modifying machinery in Arabidopsis thaliana. These allelochemicals inhibit histone deacetylases both in vitro and in vivo and exert their activity through locus-specific alterations of histone acetylation and associated gene expression. Our multilevel analysis collectively shows how plant-plant interactions interfere with a fundamental cellular process, histone acetylation, by targeting an evolutionarily highly conserved class of enzymes. PMID:26530086

  10. MECHANISMS OF FLUID SHEAR-INDUCED INHIBITION OF POPULATION GROWTH IN A RED-TIDE DINOFLAGELLATE

    EPA Science Inventory

    Net population growth of some dinoflagellates is inhibited by fluid shear at shear stresses comparable with those generated during oceanic turbulence. Decreased net growth may occur through lowered cell division, increased mortality, or both. The dominant mechanism under various ...

  11. Withaferin A inhibits in vivo growth of breast cancer cells accelerated by Notch2 knockdown.

    PubMed

    Kim, Su-Hyeong; Hahm, Eun-Ryeong; Arlotti, Julie A; Samanta, Suman K; Moura, Michelle B; Thorne, Stephen H; Shuai, Yongli; Anderson, Carolyn J; White, Alexander G; Lokshin, Anna; Lee, Joomin; Singh, Shivendra V

    2016-05-01

    The present study offers novel insights into the molecular circuitry of accelerated in vivo tumor growth by Notch2 knockdown in triple-negative breast cancer (TNBC) cells. Therapeutic vulnerability of Notch2-altered growth to a small molecule (withaferin A, WA) is also demonstrated. MDA-MB-231 and SUM159 cells were used for the xenograft studies. A variety of technologies were deployed to elucidate the mechanisms underlying tumor growth augmentation by Notch2 knockdown and its reversal by WA, including Fluorescence Molecular Tomography for measurement of tumor angiogenesis in live mice, Seahorse Flux analyzer for ex vivo measurement of tumor metabolism, proteomics, and Luminex-based cytokine profiling. Stable knockdown of Notch2 resulted in accelerated in vivo tumor growth in both cells reflected by tumor volume and/or latency. For example, the wet tumor weight from mice bearing Notch2 knockdown MDA-MB-231 cells was about 7.1-fold higher compared with control (P < 0.0001). Accelerated tumor growth by Notch2 knockdown was highly sensitive to inhibition by a promising steroidal lactone (WA) derived from a medicinal plant. Molecular underpinnings for tumor growth intensification by Notch2 knockdown included compensatory increase in Notch1 activation, increased cellular proliferation and/or angiogenesis, and increased plasma or tumor levels of growth stimulatory cytokines. WA administration reversed many of these effects providing explanation for its remarkable anti-cancer efficacy. Notch2 functions as a tumor growth suppressor in TNBC and WA offers a novel therapeutic strategy for restoring this function. PMID:27097807

  12. Plant Growth Retardants as Inhibitors of Sterol Biosynthesis in Tobacco Seedlings 12

    PubMed Central

    Douglas, Trevor J.; Paleg, Leslie G.

    1974-01-01

    Three plant-growth retardants 2′-isopropy1-4′-(trimethylammonium chloride)-5-methylphenylpiperidine carboxylate (Amo 1618), β-chloroethyltrimethylammonium chloride, and tributyl-2, 4-dichlorobenzylphosphonium chloride were tested for their effects on sterol production in, and growth of tobacco (Nicotiana tabacum) seedlings. As the concentration of each retardant increased, there was an increased inhibition of the incorporation of dl-2-14C-mevalonic acid into sterol (particularly desmethylsterol) fractions and an increased retardation of stem growth. Growth retardation was observed with both single and repeated retardant treatments, and with Amo 1618, in particular, a close quantitative relationship between inhibition of sterol biosynthesis and stem growth was obtained. Gibberellic acid completely overcame retardant effects and application of sterols also restored normal growth. It is concluded that the concept of causality in the relationship between growth retardation and gibberellin biosynthesis is probably premature, since growth retardants have a more general inhibitory action on isoprenoid biosynthesis in plants. PMID:16658867

  13. Inhibited growth of colon cancer carcinomatosis by antibodies to vascular endothelial and epidermal growth factor receptors

    PubMed Central

    Shaheen, R M; Ahmad, S A; Liu, W; Reinmuth, N; Jung, Y D; Tseng, W W; Drazan, K E; Bucana, C D; Hicklin, D J; Ellis, L M

    2001-01-01

    Vascular endothelial growth factor (VEGF) and epidermal growth factor (EGF) regulate colon cancer growth and metastasis. Previous studies utilizing antibodies against the VEGF receptor (DC101) or EGF receptor (C225) have demonstrated independently that these agents can inhibit tumour growth and induce apoptosis in colon cancer in in vivo and in vitro systems. We hypothesized that simultaneous blockade of the VEGF and EGF receptors would enhance the therapy of colon cancer in a mouse model of peritoneal carcinomatosis. Nude mice were given intraperitoneal injection of KM12L4 human colon cancer cells to generate peritoneal metastases. Mice were then randomized into one of four treatment groups: control, anti-VEGFR (DC101), anti-EGFR (C225), or DC101 and C225. Relative to the control group, treatment with DC101 or with DC101+C225 decreased tumour vascularity, growth, proliferation, formation of ascites and increased apoptosis of both tumour cells and endothelial cells. Although C225 therapy did not change any of the above parameters, C225 combined with DC101 led to a significant decrease in tumour vascularity and increases in tumour cell and endothelial cell apoptosis (vs the DC101 group). These findings suggest that DC101 inhibits angiogenesis, endothelial cell survival, and VEGF-mediated ascites formation in a murine model of colon cancer carcinomatosis. The addition of C225 to DC101 appears to lead to a further decrease in angiogenesis and ascites formation. Combination anti-VEGF and anti-EGFR therapy may represent a novel therapeutic strategy for the management of colon peritoneal carcinomatosis. © 2001 Cancer Research Campaign http://www.bjcancer.com PMID:11506500

  14. The L-type Ca2+ Channel Blocker Nifedipine Inhibits Mycelial Growth, Sporulation, and Virulence of Phytophthora capsici

    PubMed Central

    Liu, Peiqing; Gong, Jie; Ding, Xueling; Jiang, Yue; Chen, Guoliang; Li, Benjin; Weng, Qiyong; Chen, Qinghe

    2016-01-01

    The oomycete vegetable pathogen Phytophthora capsici causes significant losses of important vegetable crops worldwide. Calcium and other plant nutrients have been used in disease management of oomycete pathogens. Calcium homeostasis and signaling is essential for numerous biological processes, and Ca2+ channel blockers prevent excessive Ca2+ influx into the fungal cell. However, it is not known whether voltage-gated Ca2+ channel blockers improve control over oomycete pathogens. In the present study, we compared the inhibitory effects of CaCl2 and the extracellular Ca2+ chelator EDTA on mycelial growth and found that calcium assimilation plays a key role in P. capsici mycelial growth. Next, we involved the voltage-gated Ca2+ channel blockers verapamil (VP) and nifedipine (NFD) to analyze the effect of Ca2+ channel blockers on mycelial growth and sporulation; the results suggested that NFD, but not VP, caused significant inhibition. Ion rescue in an NFD-induced inhibition assay suggested that NFD-induced inhibition is calcium-dependent. In addition, NFD increased P. capsici sensitivity to H2O2 in a calcium-dependent manner, and extracellular calcium rescued it. Furthermore, NFD inhibited the virulence and gene expression related to its pathogenicity. These results suggest that NFD inhibits mycelial growth, sporulation, and virulence of P. capsici. PMID:27540377

  15. The L-type Ca(2+) Channel Blocker Nifedipine Inhibits Mycelial Growth, Sporulation, and Virulence of Phytophthora capsici.

    PubMed

    Liu, Peiqing; Gong, Jie; Ding, Xueling; Jiang, Yue; Chen, Guoliang; Li, Benjin; Weng, Qiyong; Chen, Qinghe

    2016-01-01

    The oomycete vegetable pathogen Phytophthora capsici causes significant losses of important vegetable crops worldwide. Calcium and other plant nutrients have been used in disease management of oomycete pathogens. Calcium homeostasis and signaling is essential for numerous biological processes, and Ca(2+) channel blockers prevent excessive Ca(2+) influx into the fungal cell. However, it is not known whether voltage-gated Ca(2+) channel blockers improve control over oomycete pathogens. In the present study, we compared the inhibitory effects of CaCl2 and the extracellular Ca(2+) chelator EDTA on mycelial growth and found that calcium assimilation plays a key role in P. capsici mycelial growth. Next, we involved the voltage-gated Ca(2+) channel blockers verapamil (VP) and nifedipine (NFD) to analyze the effect of Ca(2+) channel blockers on mycelial growth and sporulation; the results suggested that NFD, but not VP, caused significant inhibition. Ion rescue in an NFD-induced inhibition assay suggested that NFD-induced inhibition is calcium-dependent. In addition, NFD increased P. capsici sensitivity to H2O2 in a calcium-dependent manner, and extracellular calcium rescued it. Furthermore, NFD inhibited the virulence and gene expression related to its pathogenicity. These results suggest that NFD inhibits mycelial growth, sporulation, and virulence of P. capsici. PMID:27540377

  16. Inhibition of mitogen stimulated growth of human colon cancer cells by interferon.

    PubMed Central

    Hamburger, A. W.; Condon, M. E.; O'Donnell, K.

    1988-01-01

    Recombinant human interferon alpha inhibits growth of a human colon cancer cell line, Colo 205. To explore the mechanisms of IFN induced growth inhibition, quiescent Colo 205 cells were stimulated to proliferate in serum-free media by defined growth factors. Addition of insulin, transferrin and selenium (ITS) stimulated DNA synthesis, as measured by 3H-thymidine incorporation, in a dose-dependent manner. IFN-alpha (at concentrations greater than 100 U ml-1) inhibited ITS stimulated DNA synthesis by 63%. Inhibition of cell cycle traverse was confirmed by flow cytometric analysis. Although IFN inhibited growth of ITS-treated cells, steady state levels of c-myc mRNA remained above levels observed in unstimulated cells. IFN inhibited DNA synthesis only when added prior to mitogen stimulation. IFN, added 6 h after exposure of quiescent cells to ITS, failed to inhibit cell growth. Addition of increasing concentrations of ITS failed to overcome the IFN-induced growth inhibition. These results suggest IFN may inhibit cell growth in part by antagonizing the action of growth factors. Images Figure 4 PMID:3166905

  17. Gibberellins - a multifaceted hormone in plant growth regulatory network.

    PubMed

    Gantait, Saikat; Sinniah, Uma Rani; Ali, Md Nasim; Sahu, Narayan Chandra

    2015-01-01

    Plants tend to acclimatize to unfavourable environs by integrating growth and development to environmentally activated signals. Phytohormones strongly regulate convergent developmental and stress adaptive procedures and synchronize cellular reaction to the exogenous and endogenous conditions within the adaptive signaling networks. Gibberellins (GA), a group of tetracyclic diterpenoids, being vital regulators of plant growth, are accountable for regulating several aspects of growth and development of higher plants. If the element of reproduction is considered as an absolute requisite then for a majority of the higher plants GA signaling is simply indispensable. Latest reports have revealed unique conflicting roles of GA and other phytohormones in amalgamating growth and development in plants through environmental signaling. Numerous physiological researches have detailed substantial crosstalk between GA and other hormones like abscisic acid, auxin, cytokinin, and jasmonic acid. In this review, a number of explanations and clarifications for this discrepancy are explored based on the crosstalk among GA and other phytohormones.

  18. [Mycorrhizal diversity and its significance in plant growth and development].

    PubMed

    Shi, Zhaoyong; Chen, Yinglong; Liu, Runjin

    2003-09-01

    Mycorrhizal diversity, including morphological, species and functional diversity, is an integrative component of biodiversities. Many experiments showed that mycorrhizal diversity played an important role in the origin, evolution, distribution, survival, growth and development of plants. But, mycorrhizal diversity is dependent on plant diversity. It was suggested that mycorrhizal and plant diversities stimulated or retarded each other. The significance of mycorrhizal diversity in plant diversity was also discussed.

  19. Growth of Streptomyces Hygroscopicus in Rotating-Wall Bioreactor Under Simulated Microgravity Inhibits Rapamycin Production

    NASA Technical Reports Server (NTRS)

    Fang, A.; Pierson, D. L.; Mishra, S. K.; Demain, A. L.

    2000-01-01

    Growth of Streptomyces hygroscopicus under conditions of simulated microgravity in a rotating-wall bioreactor resulted in a pellet form of growth, lowered dry cell weight, and inhibition of rapamycin production. With the addition of Teflon beads to the bioreactor, growth became much less pelleted, dry cell weight increased but rapamycin production was still markedly inhibited. Growth under simulated microgravity favored extracellular production of rapamycin in contrast to a greater percentage of cell-bound rapamycin observed under normal gravity conditions.

  20. Growth of Steptomyces hygroscopicus in rotating-wall bioreactor under simulated microgravity inhibits rapamycin production

    NASA Technical Reports Server (NTRS)

    Fang, A.; Pierson, D. L.; Mishra, S. K.; Demain, A. L.

    2000-01-01

    Growth of Streptomyces hygroscopicus under conditions of simulated microgravity in a rotating-wall bioreactor resulted in a pellet form of growth, lowered dry cell weight, and inhibition of rapamycin production. With the addition of Teflon beads to the bioreactor, growth became much less pelleted, dry cell weight increased but rapamycin production was still markedly inhibited. Growth under simulated microgravity favored extracellular production of rapamycin, in contrast to a greater percentage of cell-bound rapamycin observed under normal gravity conditions.

  1. Light limitation and litter of an invasive clonal plant, Wedelia trilobata, inhibit its seedling recruitment

    PubMed Central

    Qi, Shan-Shan; Dai, Zhi-Cong; Miao, Shi-Li; Zhai, De-Li; Si, Chun-Can; Huang, Ping; Wang, Rui-Ping; Du, Dao-Lin

    2014-01-01

    Background and Aims Invasive clonal plants have two reproduction patterns, namely sexual and vegetative propagation. However, seedling recruitment of invasive clonal plants can decline as the invasion process proceeds. For example, although the invasive clonal Wedelia trilobata (Asteraceae) produces numerous seeds, few seedlings emerge under its dense population canopy in the field. In this study it is hypothesized that light limitation and the presence of a thick layer of its own litter may be the primary factors causing the failure of seedling recruitment for this invasive weed in the field. Methods A field survey was conducted to determine the allocation of resources to sexual reproduction and seedling recruitment in W. trilobata. Seed germination was also determined in the field. Effects of light and W. trilobata leaf extracts on seed germination and seedling growth were tested in the laboratory. Key Results Wedelia trilobata blooms profusely and produces copious viable seeds in the field. However, seedlings of W. trilobata were not detected under mother ramets and few emerged seedlings were found in the bare ground near to populations. In laboratory experiments, low light significantly inhibited seed germination. Leaf extracts also decreased seed germination and inhibited seedling growth, and significant interactions were found between low light and leaf extracts on seed germination. However, seeds were found to germinate in an invaded field after removal of the W. trilobata plant canopy. Conclusions The results indicate that lack of light and the presence of its own litter might be two major factors responsible for the low numbers of W. trilobata seedlings found in the field. New populations will establish from seeds once the limiting factors are eliminated, and seeds can be the agents of long-distance dispersal; therefore, prevention of seed production remains an important component in controlling the spread of this invasive clonal plant. PMID:24825293

  2. Magnetic fields: how is plant growth and development impacted?

    PubMed

    da Silva, Jaime A Teixeira; Dobránszki, Judit

    2016-03-01

    This review provides detailed insight on the effects of magnetic fields on germination, growth, development, and yield of plants focusing on ex vitro growth and development and discussing the possible physiological and biochemical responses. The MFs considered in this review range from the nanoTesla (nT) to geomagnetic levels, up to very strong MFs greater than 15 Tesla (T) and also super-weak MFs (near 0 T). The theoretical bases of the action of MFs on plant growth, which are complex, are not discussed here and thus far, there is limited mathematical background about the action of MFs on plant growth. MFs can positively influence the morphogenesis of several plants which allows them to be used in practical situations. MFs have thus far been shown to modify seed germination and affect seedling growth and development in a wide range of plants, including field, fodder, and industrial crops; cereals and pseudo-cereals; grasses; herbs and medicinal plants; horticultural crops (vegetables, fruits, ornamentals); trees; and model crops. This is important since MFs may constitute a non-residual and non-toxic stimulus. In addition to presenting and summarizing the effects of MFs on plant growth and development, we also provide possible physiological and biochemical explanations for these responses including stress-related responses of plants, explanations based on dia-, para-, and ferromagnetism, oriented movements of substances, and cellular and molecular changes.

  3. Bursts of Bipolar Microsecond Pulses Inhibit Tumor Growth

    PubMed Central

    Sano, Michael B.; Arena, Christopher B.; Bittleman, Katelyn R.; DeWitt, Matthew R.; Cho, Hyung J.; Szot, Christopher S.; Saur, Dieter; Cissell, James M.; Robertson, John; Lee, Yong W.; Davalos, Rafael V.

    2015-01-01

    Irreversible electroporation (IRE) is an emerging focal therapy which is demonstrating utility in the treatment of unresectable tumors where thermal ablation techniques are contraindicated. IRE uses ultra-short duration, high-intensity monopolar pulsed electric fields to permanently disrupt cell membranes within a well-defined volume. Though preliminary clinical results for IRE are promising, implementing IRE can be challenging due to the heterogeneous nature of tumor tissue and the unintended induction of muscle contractions. High-frequency IRE (H-FIRE), a new treatment modality which replaces the monopolar IRE pulses with a burst of bipolar pulses, has the potential to resolve these clinical challenges. We explored the pulse-duration space between 250 ns and 100 μs and determined the lethal electric field intensity for specific H-FIRE protocols using a 3D tumor mimic. Murine tumors were exposed to 120 bursts, each energized for 100 μs, containing individual pulses 1, 2, or 5 μs in duration. Tumor growth was significantly inhibited and all protocols were able to achieve complete regressions. The H-FIRE protocol substantially reduces muscle contractions and the therapy can be delivered without the need for a neuromuscular blockade. This work shows the potential for H-FIRE to be used as a focal therapy and merits its investigation in larger pre-clinical models. PMID:26459930

  4. Bursts of Bipolar Microsecond Pulses Inhibit Tumor Growth

    NASA Astrophysics Data System (ADS)

    Sano, Michael B.; Arena, Christopher B.; Bittleman, Katelyn R.; Dewitt, Matthew R.; Cho, Hyung J.; Szot, Christopher S.; Saur, Dieter; Cissell, James M.; Robertson, John; Lee, Yong W.; Davalos, Rafael V.

    2015-10-01

    Irreversible electroporation (IRE) is an emerging focal therapy which is demonstrating utility in the treatment of unresectable tumors where thermal ablation techniques are contraindicated. IRE uses ultra-short duration, high-intensity monopolar pulsed electric fields to permanently disrupt cell membranes within a well-defined volume. Though preliminary clinical results for IRE are promising, implementing IRE can be challenging due to the heterogeneous nature of tumor tissue and the unintended induction of muscle contractions. High-frequency IRE (H-FIRE), a new treatment modality which replaces the monopolar IRE pulses with a burst of bipolar pulses, has the potential to resolve these clinical challenges. We explored the pulse-duration space between 250 ns and 100 μs and determined the lethal electric field intensity for specific H-FIRE protocols using a 3D tumor mimic. Murine tumors were exposed to 120 bursts, each energized for 100 μs, containing individual pulses 1, 2, or 5 μs in duration. Tumor growth was significantly inhibited and all protocols were able to achieve complete regressions. The H-FIRE protocol substantially reduces muscle contractions and the therapy can be delivered without the need for a neuromuscular blockade. This work shows the potential for H-FIRE to be used as a focal therapy and merits its investigation in larger pre-clinical models.

  5. Growth Hormone Inhibits Hepatic De Novo Lipogenesis in Adult Mice.

    PubMed

    Cordoba-Chacon, Jose; Majumdar, Neena; List, Edward O; Diaz-Ruiz, Alberto; Frank, Stuart J; Manzano, Anna; Bartrons, Ramon; Puchowicz, Michelle; Kopchick, John J; Kineman, Rhonda D

    2015-09-01

    Patients with nonalcoholic fatty liver disease (NAFLD) are reported to have low growth hormone (GH) production and/or hepatic GH resistance. GH replacement can resolve the fatty liver condition in diet-induced obese rodents and in GH-deficient patients. However, it remains to be determined whether this inhibitory action of GH is due to direct regulation of hepatic lipid metabolism. Therefore, an adult-onset, hepatocyte-specific, GH receptor (GHR) knockdown (aLivGHRkd) mouse was developed to model hepatic GH resistance in humans that may occur after sexual maturation. Just 7 days after aLivGHRkd, hepatic de novo lipogenesis (DNL) was increased in male and female chow-fed mice, compared with GHR-intact littermate controls. However, hepatosteatosis developed only in male and ovariectomized female aLivGHRkd mice. The increase in DNL observed in aLivGHRkd mice was not associated with hyperactivation of the pathway by which insulin is classically considered to regulate DNL. However, glucokinase mRNA and protein levels as well as fructose-2,6-bisphosphate levels were increased in aLivGHRkd mice, suggesting that enhanced glycolysis drives DNL in the GH-resistant liver. These results demonstrate that hepatic GH actions normally serve to inhibit DNL, where loss of this inhibitory signal may explain, in part, the inappropriate increase in hepatic DNL observed in NAFLD patients. PMID:26015548

  6. Further evidence that naphthoquinone inhibits Toxoplasma gondii growth in vitro.

    PubMed

    da Silva, Luciana Lemos Rangel; Portes, Juliana de Araujo; de Araújo, Marlon Heggdorne; Silva, Jéssica Lays Sant'ana; Rennó, Magdalena Nascimento; Netto, Chaquip Daher; da Silva, Alcides José Monteiro; Costa, Paulo Roberto Ribeiro; De Souza, Wanderley; Seabra, Sergio Henrique; DaMatta, Renato Augusto

    2015-12-01

    Toxoplasmosis is a widely disseminated disease caused by Toxoplasma gondii, an intracellular protozoan parasite. Standard treatment causes many side effects, such as depletion of bone marrow cells, skin rashes and gastrointestinal implications. Therefore, it is necessary to find chemotherapeutic alternatives for the treatment of this disease. It was shown that a naphthoquinone derivative compound is active against T. gondii, RH strain, with an IC50 around 2.5 μM. Here, three different naphthoquinone derivative compounds with activity against leukemia cells and breast carcinoma cell were tested against T. gondii (RH strain) infected LLC-MK2 cell line. All the compounds were able to inhibit parasite growth in vitro, but one of them showed an IC50 activity below 1 μM after 48 h of treatment. The compounds showed low toxicity to the host cell. In addition, these compounds were able to induce tachyzoite-bradyzoite conversion confirmed by morphological changes, Dolichus biflorus lectin cyst wall labeling and characterization of amylopectin granules in the parasites by electron microscopy analysis using the Thierry technique. Furthermore, the compounds induced alterations on the ultrastructure of the parasite. Taken together, our results point to the naphthoquinone derivative (LQB 151) as a potential compound for the development of new drugs for the treatment of toxoplasmosis. PMID:26335616

  7. Plant Growth-Promoting Rhizobacteria Stimulate Vegetative Growth and Asexual Reproduction of Kalanchoe daigremontiana.

    PubMed

    Park, Yong-Soon; Park, Kyungseok; Kloepper, Joseph W; Ryu, Choong-Min

    2015-09-01

    Certain bacterial species associate with plant roots in soil. The plant growth-promoting rhizobacteria (PGPR) stimulate plant growth and yield in greenhouse and field. Here, we examined whether application of known bacilli PGPR strains stimulated growth and asexual reproduction in the succulent plant Kalanchoe daigremontiana. Four PGPR strains B. amyloliquefaciens IN937a, B. cereus BS107, B. pumilus INR7, and B. subtilis GB03 were applied to young plantlets by soil-drenching, and plant growth and development was monitored for three months. Aerial growth was significantly stimulated in PGPR-inoculated plants, which was observed as increases in plant height, shoot weight, and stem width. The stimulated growth influenced plant development by increasing the total number of leaves per plant. Treatment with bacilli also increased the total root biomass compared with that of control plants, and led to a 2-fold increase in asexual reproduction and plantlet formation on the leaf. Collectively, our results firstly demonstrate that Bacillus spp. promote vegetative development of K. daigremontiana, and the enhanced growth stimulates asexual reproduction and plantlet formation. PMID:26361480

  8. Plant Growth-Promoting Rhizobacteria Stimulate Vegetative Growth and Asexual Reproduction of Kalanchoe daigremontiana

    PubMed Central

    Park, Yong-Soon; Park, Kyungseok; Kloepper, Joseph W.; Ryu, Choong-Min

    2015-01-01

    Certain bacterial species associate with plant roots in soil. The plant growth-promoting rhizobacteria (PGPR) stimulate plant growth and yield in greenhouse and field. Here, we examined whether application of known bacilli PGPR strains stimulated growth and asexual reproduction in the succulent plant Kalanchoe daigremontiana. Four PGPR strains B. amyloliquefaciens IN937a, B. cereus BS107, B. pumilus INR7, and B. subtilis GB03 were applied to young plantlets by soil-drenching, and plant growth and development was monitored for three months. Aerial growth was significantly stimulated in PGPR-inoculated plants, which was observed as increases in plant height, shoot weight, and stem width. The stimulated growth influenced plant development by increasing the total number of leaves per plant. Treatment with bacilli also increased the total root biomass compared with that of control plants, and led to a 2-fold increase in asexual reproduction and plantlet formation on the leaf. Collectively, our results firstly demonstrate that Bacillus spp. promote vegetative development of K. daigremontiana, and the enhanced growth stimulates asexual reproduction and plantlet formation. PMID:26361480

  9. Plant Growth-Promoting Rhizobacteria Stimulate Vegetative Growth and Asexual Reproduction of Kalanchoe daigremontiana.

    PubMed

    Park, Yong-Soon; Park, Kyungseok; Kloepper, Joseph W; Ryu, Choong-Min

    2015-09-01

    Certain bacterial species associate with plant roots in soil. The plant growth-promoting rhizobacteria (PGPR) stimulate plant growth and yield in greenhouse and field. Here, we examined whether application of known bacilli PGPR strains stimulated growth and asexual reproduction in the succulent plant Kalanchoe daigremontiana. Four PGPR strains B. amyloliquefaciens IN937a, B. cereus BS107, B. pumilus INR7, and B. subtilis GB03 were applied to young plantlets by soil-drenching, and plant growth and development was monitored for three months. Aerial growth was significantly stimulated in PGPR-inoculated plants, which was observed as increases in plant height, shoot weight, and stem width. The stimulated growth influenced plant development by increasing the total number of leaves per plant. Treatment with bacilli also increased the total root biomass compared with that of control plants, and led to a 2-fold increase in asexual reproduction and plantlet formation on the leaf. Collectively, our results firstly demonstrate that Bacillus spp. promote vegetative development of K. daigremontiana, and the enhanced growth stimulates asexual reproduction and plantlet formation.

  10. MiR-503 inhibits hepatocellular carcinoma cell growth via inhibition of insulin-like growth factor 1 receptor

    PubMed Central

    Xiao, Yao; Tian, Qinggang; He, Jiantai; Huang, Ming; Yang, Chao; Gong, Liansheng

    2016-01-01

    MicroRNAs (miRs) have been demonstrated to play key roles in the development and progression of hepatocellular carcinoma (HCC). However, the regulatory mechanism of miR-503 in HCC has not been fully uncovered. In this study, we found that miR-503 was significantly downregulated in HCC tissues compared to nontumorous liver tissues. Moreover, lower miR-503 levels were associated with the malignant progression of HCC, and the expression of miR-503 was also decreased in several common HCC cell lines compared to normal human liver cell line THLE-3. Overexpression of miR-503 inhibited proliferation but induced apoptosis of LM3 and HepG2 cells. Bioinformatical analysis and luciferase reporter assay further identified insulin-like growth factor 1 receptor (IGF-1R) as a novel target of miR-503 in 293T cells. Moreover, overexpression of miR-503 led to a significant decrease in the protein levels of IGF-1R, while knockdown of miR-503 enhanced its protein levels in LM3 and HepG2 cells. Besides, overexpression of IGF-1R reversed the effects of miR-503-mediated HCC cell proliferation and apoptosis, indicating that IGF-1R acts as a downstream effector of miR-503 in HCC cells. Furthermore, IGF-1R was found to be significantly upregulated in HCC tissues compared to nontumorous liver tissues. In addition, the mRNA levels of IGF-1R were inversely correlated to the miR-503 levels in the HCC tissues. Thus, we demonstrate that miR-503 inhibits the proliferation and induces the apoptosis of HCC cells, partly at least, by directly targeting IGF-1R, and suggest that IGF-1R may serve as a promising target for the treatment of HCC. PMID:27366090

  11. Effusanin E suppresses nasopharyngeal carcinoma cell growth by inhibiting NF-κB and COX-2 signaling.

    PubMed

    Zhuang, Mingzhu; Zhao, Mouming; Qiu, Huijuan; Shi, Dingbo; Wang, Jingshu; Tian, Yun; Lin, Lianzhu; Deng, Wuguo

    2014-01-01

    Rabdosia serra is well known for its antibacterial, anti-inflammatory and antitumor activities, but no information has been available for the active compounds derived from this plant in inhibiting human nasopharyngeal carcinoma (NPC) cell growth. In this study, we isolated and purified a natural diterpenoid from Rabdosia serra and identified its chemical structure as effusanin E and elucidated its underlying mechanism of action in inhibiting NPC cell growth. Effusanin E significantly inhibited cell proliferation and induced apoptosis in NPC cells. Effusanin E also induced the cleavage of PARP, caspase-3 and -9 proteins and inhibited the nuclear translocation of p65 NF-κB proteins. Moreover, effusanin E abrogated the binding of NF-κB to the COX-2 promoter, thereby inhibiting the expression and promoter activity of COX-2. Pretreatment with a COX-2 or NF-κB-selective inhibitor (celecoxib or ammonium pyrrolidinedithiocarbamate) had an additive effect on the effusanin E-mediated inhibition of proliferation, while pretreatment with an activator of NF-κB/COX-2 (lipopolysaccharides) abrogated the effusanin E-mediated inhibition of proliferation. Effusanin E also significantly suppressed tumor growth in a xenograft mouse model without obvious toxicity, furthermore, the expression of p50 NF-κB and COX-2 were down-regulated in the tumors of nude mice. These data suggest that effusanin E suppresses p50/p65 proteins to down-regulate COX-2 expression, thereby inhibiting NPC cell growth. Our findings provide new insights into exploring effusanin E as a potential therapeutic compound for the treatment of human nasopharyngeal carcinoma. PMID:25333664

  12. Effusanin E Suppresses Nasopharyngeal Carcinoma Cell Growth by Inhibiting NF-κB and COX-2 Signaling

    PubMed Central

    Zhuang, Mingzhu; Zhao, Mouming; Qiu, Huijuan; Shi, Dingbo; Wang, Jingshu; Tian, Yun; Lin, Lianzhu; Deng, Wuguo

    2014-01-01

    Rabdosia serra is well known for its antibacterial, anti-inflammatory and antitumor activities, but no information has been available for the active compounds derived from this plant in inhibiting human nasopharyngeal carcinoma (NPC) cell growth. In this study, we isolated and purified a natural diterpenoid from Rabdosia serra and identified its chemical structure as effusanin E and elucidated its underlying mechanism of action in inhibiting NPC cell growth. Effusanin E significantly inhibited cell proliferation and induced apoptosis in NPC cells. Effusanin E also induced the cleavage of PARP, caspase-3 and -9 proteins and inhibited the nuclear translocation of p65 NF-κB proteins. Moreover, effusanin E abrogated the binding of NF-κB to the COX-2 promoter, thereby inhibiting the expression and promoter activity of COX-2. Pretreatment with a COX-2 or NF-κB-selective inhibitor (celecoxib or ammonium pyrrolidinedithiocarbamate) had an additive effect on the effusanin E-mediated inhibition of proliferation, while pretreatment with an activator of NF-κB/COX-2 (lipopolysaccharides) abrogated the effusanin E-mediated inhibition of proliferation. Effusanin E also significantly suppressed tumor growth in a xenograft mouse model without obvious toxicity, furthermore, the expression of p50 NF-κB and COX-2 were down-regulated in the tumors of nude mice. These data suggest that effusanin E suppresses p50/p65 proteins to down-regulate COX-2 expression, thereby inhibiting NPC cell growth. Our findings provide new insights into exploring effusanin E as a potential therapeutic compound for the treatment of human nasopharyngeal carcinoma. PMID:25333664

  13. Plant growth regulators enhance gold uptake in Brassica juncea.

    PubMed

    Kulkarni, Manoj G; Stirk, Wendy A; Southway, Colin; Papenfus, Heino B; Swart, Pierre A; Lux, Alexander; Vaculík, Marek; Martinka, Michal; Van Staden, Johannes

    2013-01-01

    The use of plant growth regulators is well established and they are used in many fields of plant science for enhancing growth. Brassica juncea plants were treated with 2.5, 5.0 and 7.5 microM auxin indole-3-butyric acid (IBA), which promotes rooting. The IBA-treated plants were also sprayed with 100 microM gibberellic acid (GA3) and kinetin (Kin) to increase leaf-foliage. Gold (I) chloride (AuCl) was added to the growth medium of plants to achieve required gold concentration. The solubilizing agent ammonium thiocyanate (1 g kg(-1)) (commonly used in mining industries to solubilize gold) was added to the nutrient solution after six weeks of growth and, two weeks later, plants were harvested. Plant growth regulators improved shoot and root dry biomass of B. juncea plants. Inductively Coupled Plasma Optical Emission Spectrometry analysis showed the highest Au uptake for plants treated with 5.0 microM IBA. The average recovery of Au with this treatment was significantly greater than the control treatment by 45.8 mg kg(-1) (155.7%). The other IBA concentrations (2.5 and 7.5 microM) also showed a significant increase in Au uptake compared to the control plants by 14.7 mg kg(-1) (50%) and 42.5 mg kg(-1) (144.5%) respectively. A similar trend of Au accumulation was recorded in the roots of B. juncea plants. This study conducted in solution culture suggests that plant growth regulators can play a significant role in improving phytoextraction of Au.

  14. Chemical Growth Regulators for Guayule Plants

    NASA Technical Reports Server (NTRS)

    Dastoor, M. N.; Schubert, W. W.; Petersen, G. R.

    1982-01-01

    Test Tubes containing Guayule - tissue cultures were used in experiments to test effects of chemical-growth regulators. The shoots grew in response to addition of 2-(3,4-dichlorophenoxy)-triethylamine (triethylamine (TEA) derivative) to agar medium. Preliminary results indicate that a class of compounds that promotes growth in soil may also promote growth in a culture medium. Further experiments are needed to define the effect of the TEA derivative.

  15. The contribution of Trichoderma to balancing the costs of plant growth and defense.

    PubMed

    Hermosa, Rosa; Rubio, M Belén; Cardoza, Rosa E; Nicolás, Carlos; Monte, Enrique; Gutiérrez, Santiago

    2013-06-01

    Trichoderma is a fungal genus of cosmopolitan distribution and high biotechnological value, with several species currently used as biological control agents. Additionally, the enzyme systems of the fungus are widely applied in industry. Species of Trichoderma protect plants against the attack of soil-borne plant pathogens by competing for nutrients and inhibiting or killing plant pathogenic fungi and oomycetes, through the production of antibiotics and/or hydrolytic enzymes. In addition to the role of Trichoderma spp. as biocontrol agents, they have other beneficial effects on plants, including the stimulation of plant defenses and the promotion of plant growth. In this review, we focus on the complex plant defense signaling network that allows the recognition of fungi as non-hostile microbes, including microbial-associated molecular patterns (MAMPs), damage-associated molecular patterns (DAMPs) and secreted elicitors. We also examine how fungal interactions with plant receptors can activate induced resistance by priming and balancing plant defense and growth responses. Our observations are integrated into a model describing Trichoderma-plant hormone signaling network interactions.

  16. Tubular Membrane Plant-Growth Unit

    NASA Technical Reports Server (NTRS)

    Dreschel, Thomas W.

    1992-01-01

    Hydroponic system controls nutrient solution for growing crops in space. Pump draws nutrient solution along inside of tubular membrane in pipe from reservoir, maintaining negative pressure in pipe. Roots of plants in slot extract nutrient through membrane within pipe. Crop plants such as wheat, rice, lettuce, tomatoes, soybeans, and beans grown successfully with system.

  17. Cadaverine: a lysine catabolite involved in plant growth and development.

    PubMed

    Tomar, Pushpa C; Lakra, Nita; Mishra, S N

    2013-10-01

    The cadaverine (Cad) a diamine, imino compound produced as a lysine catabolite is also implicated in growth and development of plants depending on environmental condition. This lysine catabolism is catalyzed by lysine decarboxylase, which is developmentally regulated. However, the limited role of Cad in plants is reported, this review is tempted to focus the metabolism and its regulation, transport and responses, interaction and cross talks in higher plants. The Cad varied presence in plant parts/products suggests it as a potential candidate for taxonomic marker as well as for commercial exploitation along with growth and development.

  18. Chemical PARP Inhibition Enhances Growth of Arabidopsis and Reduces Anthocyanin Accumulation and the Activation of Stress Protective Mechanisms

    PubMed Central

    Schulz, Philipp; Neukermans, Jenny; Van Der Kelen, Katrien; Mühlenbock, Per; Van Breusegem, Frank; Noctor, Graham; Teige, Markus; Metzlaff, Michael; Hannah, Matthew A.

    2012-01-01

    Poly-ADP-ribose polymerase (PARP) post-translationally modifies proteins through the addition of ADP-ribose polymers, yet its role in modulating plant development and stress responses is only poorly understood. The experiments presented here address some of the gaps in our understanding of its role in stress tolerance and thereby provide new insights into tolerance mechanisms and growth. Using a combination of chemical and genetic approaches, this study characterized phenotypes associated with PARP inhibition at the physiological level. Molecular analyses including gene expression analysis, measurement of primary metabolites and redox metabolites were used to understand the underlying processes. The analysis revealed that PARP inhibition represses anthocyanin and ascorbate accumulation under stress conditions. The reduction in defense is correlated with enhanced biomass production. Even in unstressed conditions protective genes and molecules are repressed by PARP inhibition. The reduced anthocyanin production was shown to be based on the repression of transcription of key regulatory and biosynthesis genes. PARP is a key factor for understanding growth and stress responses of plants. PARP inhibition allows plants to reduce protection such as anthocyanin, ascorbate or Non-Photochemical-Quenching whilst maintaining high energy levels likely enabling the observed enhancement of biomass production under stress, opening interesting perspectives for increasing crop productivity. PMID:22662141

  19. Interplay between cell growth and cell cycle in plants.

    PubMed

    Sablowski, Robert; Carnier Dornelas, Marcelo

    2014-06-01

    The growth of organs and whole plants depends on both cell growth and cell-cycle progression, but the interaction between both processes is poorly understood. In plants, the balance between growth and cell-cycle progression requires coordinated regulation of four different processes: macromolecular synthesis (cytoplasmic growth), turgor-driven cell-wall extension, mitotic cycle, and endocycle. Potential feedbacks between these processes include a cell-size checkpoint operating before DNA synthesis and a link between DNA contents and maximum cell size. In addition, key intercellular signals and growth regulatory genes appear to target at the same time cell-cycle and cell-growth functions. For example, auxin, gibberellin, and brassinosteroid all have parallel links to cell-cycle progression (through S-phase Cyclin D-CDK and the anaphase-promoting complex) and cell-wall functions (through cell-wall extensibility or microtubule dynamics). Another intercellular signal mediated by microtubule dynamics is the mechanical stress caused by growth of interconnected cells. Superimposed on developmental controls, sugar signalling through the TOR pathway has recently emerged as a central control point linking cytoplasmic growth, cell-cycle and cell-wall functions. Recent progress in quantitative imaging and computational modelling will facilitate analysis of the multiple interconnections between plant cell growth and cell cycle and ultimately will be required for the predictive manipulation of plant growth.

  20. Nitrate inhibition of legume nodule growth and activity. I. Long term studies with a continuous supply of nitrate

    SciTech Connect

    Streeter, J.G.

    1985-02-01

    The synthesis and accumulation of nitrite has been suggested as a causative factor in the inhibition of legume nodules supplied with nitrate. Plants were grown in sand culture with a moderate level of nitrate (2.1 to 6.4 millimolar) supplied continuously from seed germination to 30 to 50 days after planting. In a comparison of nitrate treatments, a highly significant negative correlation between nitrite concentration in soybean (Glycine max (L.) Merr.) nodules and nodule fresh weight per shoot dry weight was found even when bacteroids lacked nitrate reductase (NR). However, in a comparison of two Rhizobium japonicum strains, there was only 12% as much nitrite in nodules formed by NR/sup -/ R. japonicum as in nodules formed by NR/sup +/ R. japonicum, and growth and acetylene reduction activity of both types of nodules was about equally inhibited. The very small concentration of nitrite found in P. vulgaris nodules was probably below that required for the inhibition of nitrogenase based on published in vitro experiments, and yet the specific acetylene reduction activity was inhibited 83% by nitrate. The overall results do not support the idea that nitrite plays a role in the inhibition of nodule growth and nitrogenase activity by nitrate.

  1. Expert System Control of Plant Growth in an Enclosed Space

    NASA Technical Reports Server (NTRS)

    May, George; Lanoue, Mark; Bathel, Matthew; Ryan, Robert E.

    2008-01-01

    The Expert System is an enclosed, controlled environment for growing plants, which incorporates a computerized, knowledge-based software program that is designed to capture the knowledge, experience, and problem-solving skills of one or more human experts in a particular discipline. The Expert System is trained to analyze crop/plant status, to monitor the condition of the plants and the environment, and to adjust operational parameters to optimize the plant-growth process. This system is intended to provide a way to remotely control plant growth with little or no human intervention. More specifically, the term control implies an autonomous method for detecting plant states such as health (biomass) or stress and then for recommending and implementing cultivation and/or remediation to optimize plant growth and to minimize consumption of energy and nutrients. Because of difficulties associated with delivering energy and nutrients remotely, a key feature of this Expert System is its ability to minimize this effort and to achieve optimum growth while taking into account the diverse range of environmental considerations that exist in an enclosed environment. The plant-growth environment for the Expert System could be made from a variety of structures, including a greenhouse, an underground cavern, or another enclosed chamber. Imaging equipment positioned within or around the chamber provides spatially distributed crop/plant-growth information. Sensors mounted in the chamber provide data and information pertaining to environmental conditions that could affect plant development. Lamps in the growth environment structure supply illumination, and other additional equipment in the chamber supplies essential nutrients and chemicals.

  2. Compounds in a particular production lot of tryptic soy broth inhibit Staphylococcus aureus cell growth.

    PubMed

    Ishii, Masaki; Matsumoto, Yasuhiko; Sekimizu, Kazuhisa

    2015-06-01

    Staphylococcus aureus Newman strain and several methicillin-resistant S. aureus (MRSA) clinical isolates were grown on agar plates prepared with conventional lots of tryptic soy broth (TSB). Cell growth of these strains was inhibited on agar plates containing TSB of a particular product lot (lot A), whereas the cell growth of S. aureus RN4220 strain and several other MRSA clinical isolates was not inhibited. The cell growth of a strain of S. epidermidis was also inhibited on agar plates containing TSB of lot A, whereas the cell growth of Bacillus subtilis, Lactococcus lactis, Klebsiella pneumonia, Salmonella enterica, Serratia marcescens, Pseudomonas aeruginosa, and Escherichia coli was not inhibited. Although cell growth of the Newman strain was inhibited on agar plates containing TSB of lot A that was autoclaved in stainless steel or glass containers, cell growth inhibition was not observed when the medium was autoclaved in polypropylene containers. Compounds that inhibited the cell growth of the Newman strain were extracted from a polypropylene tube that was preincubated with liquid medium prepared from TSB of lot A. These findings suggest that polypropylene-binding compounds in TSB of lot A inhibited the cell growth of S. aureus Newman strain, some MRSA clinical isolates, and S. epidermidis.

  3. Influence of some growth regulators and cations on inhibition of chlorophyll biosynthesis by lead in maize

    SciTech Connect

    Sinha, S.K. ); Srivastava, H.S. ); Tripathi, R.D. )

    1993-08-01

    Phytotoxic effects of Pb pollution are well established. In order to analyse the physiological basis of toxic symptoms and of reduced plant productivity, its effect on chlorophyll content has been examined in some plants. Thus, a decrease in total chlorophyll content during Pb supply has been observed in oats, mung beam, pea, etc. The activity of delta aminolevulinic acid dehydratase, an important enzyme in the biosynthesis of heme pigments, is inhibited by Pb in mung bean and several other species. This observation may perhaps indicate that a reduction in chlorophyll content in the presence of lead is due to an inhibition of pigment synthesis. The effect of Pb on greening maize leaf segments in the presence of various precursors of chlorophyll has been studied in the present investigation to evaluate this hypothesis. The effect of some growth regulators and cations, which could otherwise modify chlorophyll biosynthesis, has been examined to see whether the toxic effects of Pb on photosynthetic pigments could also be modified by these effectors. 16 refs., 4 tabs.

  4. Mechanisms of growth inhibition of Phytomonas serpens by the alkaloids tomatine and tomatidine

    PubMed Central

    Medina, Jorge Mansur; Rodrigues, Juliany Cola Fernandes; Moreira, Otacilio C; Atella, Geórgia; de Souza, Wanderley; Barrabin, Hector

    2015-01-01

    Phytomonas serpens are flagellates in the family Trypanosomatidae that parasitise the tomato plant (Solanum lycopersicum L.), which results in fruits with low commercial value. The tomato glycoalkaloid tomatine and its aglycone tomatidine inhibit the growth of P. serpens in axenic cultures. Tomatine, like many other saponins, induces permeabilisation of the cell membrane and a loss of cell content, including the cytosolic enzyme pyruvate kinase. In contrast, tomatidine does not cause permeabilisation of membranes, but instead provokes morphological changes, including vacuolisation. Phytomonas treated with tomatidine show an increased accumulation of labelled neutral lipids (BODYPY-palmitic), a notable decrease in the amount of C24-alkylated sterols and an increase in zymosterol content. These results are consistent with the inhibition of 24-sterol methyltransferase (SMT), which is an important enzyme that is responsible for the methylation of sterols at the 24 position. We propose that the main target of tomatidine is the sterols biosynthetic pathway, specifically, inhibition of the 24-SMT. Altogether, the results obtained in the present paper suggest a more general effect of alkaloids in trypanosomatids, which opens potential therapeutic possibilities for the treatment of the diseases caused by these pathogens. PMID:25742263

  5. Structure-Function Analysis of Rny1 in tRNA Cleavage and Growth Inhibition

    PubMed Central

    Luhtala, Natalie; Parker, Roy

    2012-01-01

    T2 ribonucleases are conserved nucleases that affect a variety of processes in eukaryotic cells including the regulation of self-incompatibility by S-RNases in plants, modulation of host immune cell responses by viral and schistosome T2 enzymes, and neurological development and tumor progression in humans. These roles for RNaseT2’s can be due to catalytic or catalytic-independent functions of the molecule. Despite this broad importance, the features of RNaseT2 proteins that modulate catalytic and catalytic-independent functions are poorly understood. Herein, we analyze the features of Rny1 in Saccharomyces cerevisiae to determine the requirements for cleaving tRNA in vivo and for inhibiting cellular growth in a catalytic-independent manner. We demonstrate that catalytic-independent inhibition of growth is a combinatorial property of the protein and is affected by a fungal-specific C-terminal extension, the conserved catalytic core, and the presence of a signal peptide. Catalytic functions of Rny1 are independent of the C-terminal extension, are affected by many mutations in the catalytic core, and also require a signal peptide. Biochemical flotation assays reveal that in rny1Δ cells, some tRNA molecules associate with membranes suggesting that cleavage of tRNAs by Rny1 can involve either tRNA association with, or uptake into, membrane compartments. PMID:22829915

  6. Inhibition of Bacterial Growth and Biofilm Production by Constituents from Hypericum spp

    PubMed Central

    Sarkisian, S.A.; Janssen, M.J.; Matta, H.; Henry, G.E.; LaPlante, K.L.; Rowley, D.C.

    2011-01-01

    Biofilm embedded bacterial pathogens such as Staphylococcus spp., Escherichia coli, Pseudomonas aeruginosa, and Acinetobacter baumannii are difficult to eradicate and are major sources of bacterial infections. New drugs are needed to combat these pathogens. Hypericum is a plant genus that contains species known to have antimicrobial properties. However, the specific constituents responsible for the antimicrobial properties are not entirely known, nor have most compounds been tested as inhibitors of biofilm development. The investigation presented here tested seven secondary metabolites isolated from the species Hypericum densiflorum, Hypericumellipticum, Hypericum prolificum and Hypericum punctatum as inhibitors of bacterial growth and biofilm production. Assays were conducted against Staphylococcus epidermidis, Staphylococcusaureus, clinical methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, Escherichia coli, and Acinetobacter baumannii. Five of the seven compounds demonstrated growth inhibition against the Gram-positive bacteria with minimum inhibitory concentrations (MIC) ranging from 1.95 μg/mL to 7.81 μg/mL. Four of the secondary metabolites inhibited biofilm production by certain Gram-positive strains at sub-MIC concentrations. PMID:22170780

  7. Growth form evolution and shifting habitat specialization in annual plants.

    PubMed

    Bonser, S P; Geber, M A

    2005-07-01

    Optimal plant growth form should vary across environments. We examined the potential for mutations causing large changes in growth form to produce new optimal phenotypes across light environments. We predicted that the upright growth form would be favoured in a light limiting environment as leaves were in a position to maximize light interception, while a rosette (leaves in a basal position) growth form would be favoured in a high light environment. Growth form genotypes of Brassica rapa (upright wild-type and rosette mutants) and Arabidopsis thaliana (large rosette wild-type and increasingly upright growth form mutants) were grown in a greenhouse in control (ambient) and filtered (low) light treatments. Compared to upright genotypes, rosette genotypes had relatively high fitness in control light but had a relatively large fitness reduction in filtered light. Our results demonstrate the potential importance of rapid growth form evolution in plant adaptation to new or changing environments.

  8. Plant growth-promoting rhizobacteria and root system functioning.

    PubMed

    Vacheron, Jordan; Desbrosses, Guilhem; Bouffaud, Marie-Lara; Touraine, Bruno; Moënne-Loccoz, Yvan; Muller, Daniel; Legendre, Laurent; Wisniewski-Dyé, Florence; Prigent-Combaret, Claire

    2013-01-01

    The rhizosphere supports the development and activity of a huge and diversified microbial community, including microorganisms capable to promote plant growth. Among the latter, plant growth-promoting rhizobacteria (PGPR) colonize roots of monocots and dicots, and enhance plant growth by direct and indirect mechanisms. Modification of root system architecture by PGPR implicates the production of phytohormones and other signals that lead, mostly, to enhanced lateral root branching and development of root hairs. PGPR also modify root functioning, improve plant nutrition and influence the physiology of the whole plant. Recent results provided first clues as to how PGPR signals could trigger these plant responses. Whether local and/or systemic, the plant molecular pathways involved remain often unknown. From an ecological point of view, it emerged that PGPR form coherent functional groups, whose rhizosphere ecology is influenced by a myriad of abiotic and biotic factors in natural and agricultural soils, and these factors can in turn modulate PGPR effects on roots. In this paper, we address novel knowledge and gaps on PGPR modes of action and signals, and highlight recent progress on the links between plant morphological and physiological effects induced by PGPR. We also show the importance of taking into account the size, diversity, and gene expression patterns of PGPR assemblages in the rhizosphere to better understand their impact on plant growth and functioning. Integrating mechanistic and ecological knowledge on PGPR populations in soil will be a prerequisite to develop novel management strategies for sustainable agriculture.

  9. Plant growth-promoting rhizobacteria and root system functioning

    PubMed Central

    Vacheron, Jordan; Desbrosses, Guilhem; Bouffaud, Marie-Lara; Touraine, Bruno; Moënne-Loccoz, Yvan; Muller, Daniel; Legendre, Laurent; Wisniewski-Dyé, Florence; Prigent-Combaret, Claire

    2013-01-01

    The rhizosphere supports the development and activity of a huge and diversified microbial community, including microorganisms capable to promote plant growth. Among the latter, plant growth-promoting rhizobacteria (PGPR) colonize roots of monocots and dicots, and enhance plant growth by direct and indirect mechanisms. Modification of root system architecture by PGPR implicates the production of phytohormones and other signals that lead, mostly, to enhanced lateral root branching and development of root hairs. PGPR also modify root functioning, improve plant nutrition and influence the physiology of the whole plant. Recent results provided first clues as to how PGPR signals could trigger these plant responses. Whether local and/or systemic, the plant molecular pathways involved remain often unknown. From an ecological point of view, it emerged that PGPR form coherent functional groups, whose rhizosphere ecology is influenced by a myriad of abiotic and biotic factors in natural and agricultural soils, and these factors can in turn modulate PGPR effects on roots. In this paper, we address novel knowledge and gaps on PGPR modes of action and signals, and highlight recent progress on the links between plant morphological and physiological effects induced by PGPR. We also show the importance of taking into account the size, diversity, and gene expression patterns of PGPR assemblages in the rhizosphere to better understand their impact on plant growth and functioning. Integrating mechanistic and ecological knowledge on PGPR populations in soil will be a prerequisite to develop novel management strategies for sustainable agriculture. PMID:24062756

  10. Rewiring of jasmonate and phytochrome B signalling uncouples plant growth-defense tradeoffs.

    PubMed

    Campos, Marcelo L; Yoshida, Yuki; Major, Ian T; de Oliveira Ferreira, Dalton; Weraduwage, Sarathi M; Froehlich, John E; Johnson, Brendan F; Kramer, David M; Jander, Georg; Sharkey, Thomas D; Howe, Gregg A

    2016-01-01

    Plants resist infection and herbivory with innate immune responses that are often associated with reduced growth. Despite the importance of growth-defense tradeoffs in shaping plant productivity in natural and agricultural ecosystems, the molecular mechanisms that link growth and immunity are poorly understood. Here, we demonstrate that growth-defense tradeoffs mediated by the hormone jasmonate are uncoupled in an Arabidopsis mutant (jazQ phyB) lacking a quintet of Jasmonate ZIM-domain transcriptional repressors and the photoreceptor phyB. Analysis of epistatic interactions between jazQ and phyB reveal that growth inhibition associated with enhanced anti-insect resistance is likely not caused by diversion of photoassimilates from growth to defense but rather by a conserved transcriptional network that is hardwired to attenuate growth upon activation of jasmonate signalling. The ability to unlock growth-defense tradeoffs through relief of transcription repression provides an approach to assemble functional plant traits in new and potentially useful ways. PMID:27573094

  11. Experiments with Corn To Demonstrate Plant Growth and Development.

    ERIC Educational Resources Information Center

    Haldeman, Janice H.; Gray, Margarit S.

    2000-01-01

    Explores using corn seeds to demonstrate plant growth and development. This experiment allows students to formulate hypotheses, observe and record information, and practice mathematics. Presents background information, materials, procedures, and observations. (SAH)

  12. Clinostat Delivers Power To Plant-Growth Cabinets

    NASA Technical Reports Server (NTRS)

    Bushong, Wilton E.; Fox, Ronald C.; Brown, Christopher S.; Biro, Ronald R.; Dreshel, Thomas W.

    1993-01-01

    Clinostat rotates coaxial pair of plant-growth cabinets about horizontal axis while supplying cabinets with electric power for built-in computers, lamps, fans, and auxiliary equipment, such as nutrient pumps. Each cabinet self-contained unit for growing plants in controlled environment. By rotating cabinets and contents about horizontal axis, scientists simulate and study some of effects of microgravity on growth of plants. Clinostat includes vertical aluminum mounting bracket on horizontal aluminum base. Bearings on bracket hold shaft with V-belt pulley. At each end of shaft, circular plate holds frame mount for cabinet. Mounting plates also used to hold transparent sealed growth chambers described in article, "Sealed Plant-Growth Chamber For Clinostat" (KSC-11538).

  13. 5-Aminolevulinic Acid Thins Pear Fruits by Inhibiting Pollen Tube Growth via Ca(2+)-ATPase-Mediated Ca(2+) Efflux.

    PubMed

    An, Yuyan; Li, Jie; Duan, Chunhui; Liu, Longbo; Sun, Yongping; Cao, Rongxiang; Wang, Liangju

    2016-01-01

    Chemical fruit thinning has become a popular practice in modern fruit orchards for achieving high quality fruits, reducing costs of hand thinning and promoting return bloom. However, most of the suggested chemical thinners are often concerned for their detrimental effects and environmental problems. 5-Aminolevulic acid (ALA) is a natural, nontoxic, biodegradable, and environment-friendly plant growth regulator. One of its outstanding roles is improving plant photosynthesis and fruit quality. Here, results showed that applying 100-200 mg/L ALA at full bloom stage significantly reduced pear fruit set. Both in vivo and in vitro studies showed that ALA significantly inhibited pollen germination and tube growth. ALA decreased not only cytosolic Ca(2+) concentration ([Ca(2+)]cyt) but also "tip-focused" [Ca(2+)]cyt gradient, indicating that ALA inhibited pollen tube growth by down-regulating calcium signaling. ALA drastically enhanced pollen Ca(2+)-ATPase activity, suggesting that ALA-induced decrease of calcium signaling probably resulted from activating calcium pump. The significant negative correlations between Ca(2+)-ATPase activity and pollen germination or pollen tube length further demonstrated the critical role of calcium pump in ALA's negative effect on pollen germination. Taken together, our results suggest that ALA at low concentrations is a potential biochemical thinner, and it inhibits pollen germination and tube growth via Ca(2+) efflux by activating Ca(2+)-ATPase, thereby thinning fruits by preventing fertilization.

  14. 5-Aminolevulinic Acid Thins Pear Fruits by Inhibiting Pollen Tube Growth via Ca2+-ATPase-Mediated Ca2+ Efflux

    PubMed Central

    An, Yuyan; Li, Jie; Duan, Chunhui; Liu, Longbo; Sun, Yongping; Cao, Rongxiang; Wang, Liangju

    2016-01-01

    Chemical fruit thinning has become a popular practice in modern fruit orchards for achieving high quality fruits, reducing costs of hand thinning and promoting return bloom. However, most of the suggested chemical thinners are often concerned for their detrimental effects and environmental problems. 5-Aminolevulic acid (ALA) is a natural, nontoxic, biodegradable, and environment-friendly plant growth regulator. One of its outstanding roles is improving plant photosynthesis and fruit quality. Here, results showed that applying 100–200 mg/L ALA at full bloom stage significantly reduced pear fruit set. Both in vivo and in vitro studies showed that ALA significantly inhibited pollen germination and tube growth. ALA decreased not only cytosolic Ca2+ concentration ([Ca2+]cyt) but also “tip-focused” [Ca2+]cyt gradient, indicating that ALA inhibited pollen tube growth by down-regulating calcium signaling. ALA drastically enhanced pollen Ca2+-ATPase activity, suggesting that ALA-induced decrease of calcium signaling probably resulted from activating calcium pump. The significant negative correlations between Ca2+-ATPase activity and pollen germination or pollen tube length further demonstrated the critical role of calcium pump in ALA's negative effect on pollen germination. Taken together, our results suggest that ALA at low concentrations is a potential biochemical thinner, and it inhibits pollen germination and tube growth via Ca2+ efflux by activating Ca2+-ATPase, thereby thinning fruits by preventing fertilization. PMID:26904082

  15. Plant Growth Models Using Artificial Neural Networks

    NASA Technical Reports Server (NTRS)

    Bubenheim, David

    1997-01-01

    In this paper, we descrive our motivation and approach to devloping models and the neural network architecture. Initial use of the artificial neural network for modeling the single plant process of transpiration is presented.

  16. An engineering analysis of a closed cycle plant growth module

    NASA Technical Reports Server (NTRS)

    Stickford, G. H., Jr.; Jakob, F. E.; Landstrom, D. K.

    1986-01-01

    The SOLGEM model is a numerical engineering model which solves the flow and energy balance equations for the air flowing through a growing environment, assuming quasi-steady state conditions within the system. SOLGEM provides a dynamic simulation of the controlled environment system in that the temperature and flow conditions of the growing environment are estimated on an hourly basis in response to the weather data and the plant growth parameters. The flow energy balance considers the incident solar flux; incoming air temperature, humidity, and flow rate; heat exchange with the roof and floor; and heat and moisture exchange with the plants. A plant transpiration subroutine was developed based plant growth research facility, intended for the study of bioregenerative life support theories. The results of a performance analysis of the plant growth module are given. The estimated energy requirements of the module components and the total energy are given.

  17. [Protective properties of avermectine complex and plant growth regulators].

    PubMed

    Iamborko, N A; Pindrus, A A

    2009-01-01

    Antimutagen properties of avermectine complex of Avercom synthesized by Streptomyces avermitilis UCM Ac-2161, and growth regulators of plants (GRP) of bioagrostim-extra, ivin and emistim-C have been revealed in experiments with test-cultures of Salmonella typhimurium TA 100, TA 98. Avercom and plant growth regulators neutralize by toxication 27-48% and mutagen action of pesticides on soil microbial associations by 19.0-30.0%.

  18. Di(2-ethylhexyl) phthalate inhibits antral follicle growth, induces atresia, and inhibits steroid hormone production in cultured mouse antral follicles

    SciTech Connect

    Hannon, Patrick R. Brannick, Katherine E. Wang, Wei Gupta, Rupesh K. Flaws, Jodi A.

    2015-04-01

    Di(2-ethylhexyl) phthalate (DEHP) is a ubiquitous environmental toxicant found in consumer products that causes ovarian toxicity. Antral follicles are the functional ovarian units and must undergo growth, survival from atresia, and proper regulation of steroidogenesis to ovulate and produce hormones. Previous studies have determined that DEHP inhibits antral follicle growth and decreases estradiol levels in vitro; however, the mechanism by which DEHP elicits these effects is unknown. The present study tested the hypothesis that DEHP directly alters regulators of the cell cycle, apoptosis, and steroidogenesis to inhibit antral follicle functionality. Antral follicles from adult CD-1 mice were cultured with vehicle control or DEHP (1–100 μg/ml) for 24–96 h to establish the temporal effects of DEHP on the follicle. Following 24–96 h of culture, antral follicles were subjected to gene expression analysis, and media were subjected to measurements of hormone levels. DEHP increased the mRNA levels of cyclin D2, cyclin dependent kinase 4, cyclin E1, cyclin A2, and cyclin B1 and decreased the levels of cyclin-dependent kinase inhibitor 1A prior to growth inhibition. Additionally, DEHP increased the mRNA levels of BCL2-associated agonist of cell death, BCL2-associated X protein, BCL2-related ovarian killer protein, B-cell leukemia/lymphoma 2, and Bcl2-like 10, leading to an increase in atresia. Further, DEHP decreased the levels of progesterone, androstenedione, and testosterone prior to the decrease in estradiol levels, with decreased mRNA levels of side-chain cleavage, 17α-hydroxylase-17,20-desmolase, 17β-hydroxysteroid dehydrogenase, and aromatase. Collectively, DEHP directly alters antral follicle functionality by inhibiting growth, inducing atresia, and inhibiting steroidogenesis. - Highlights: • DEHP inhibits antral follicle growth by dysregulating cell cycle regulators. • DEHP induces antral follicle atresia by dysregulating apoptosis regulators. • DEHP

  19. Environmental estrogens inhibit growth of rainbow trout (Oncorhynchus mykiss) by modulating the growth hormone-insulin-like growth factor system.

    PubMed

    Hanson, Andrea M; Kittilson, Jeffrey D; Martin, Lincoln E; Sheridan, Mark A

    2014-01-15

    Although environmental estrogens (EE) have been found to disrupt a wide variety of developmental and reproductive processes in vertebrates, there is a paucity of information concerning their effects on organismal growth, particularly postembryonic growth. In this study, we exposed juvenile rainbow trout (Oncorhynchus mykiss) to 17β-estradiol (E2) β-sitosterol (βS), or 4-n-nonylphenol (NP) to assess the effects of EE on overall organismal growth and on the growth hormone-insulin-like-growth factor (GH-IGF) system. EE treatment significantly reduced food conversion, body condition, and body growth. EE-inhibited growth resulted from alterations in peripheral elements of the GH-IGF system, which includes multiple GH receptors (GHRs), IGFs, and IGF receptors (IGFRs). In general, E2, βS, and NP reduced the expression of GHRs, IGFs, and IGFRs; however, the effects varied in an EE-, tissue-, element type-specific manner. For example, in liver, E2 was more efficacious than either βS, and NP in reducing GHR expression, and the effect of E2 was greater on GHR 1 than GHR2 mRNA. By contrast, in gill, all EEs affected GHR expression in a similar manner and there was no difference in the effect on GHR1 and GHR 2 mRNA. With regard to IGF expression, all EEs reduced hepatic IGF1 and IGF2 mRNA levels, whereas as in gill, only E2 and NP significantly reduced IGF1 and IGF2 expression. Lastly, E2 and NP reduced the expression of IGFR1A and IGFR1B mRNA expression similarly in gill and red and white muscle, whereas βS had no effect on expression of IGFR mRNAs. These findings indicate that EEs disrupt post-embryonic growth by reducing GH sensitivity, IGF production, and IGF sensitivity.

  20. Inhibition of root meristem growth by cadmium involves nitric oxide-mediated repression of auxin accumulation and signalling in Arabidopsis.

    PubMed

    Yuan, Hong-Mei; Huang, Xi

    2016-01-01

    The root is the first plant organ to get in contact with the toxin cadmium (Cd), which is a widespread soil contaminant. Cd inhibits the growth of the primary root, but the mechanisms underlying this inhibition remain elusive. In this study, we used physiological, pharmacological and genetic approaches to investigate the roles of nitric oxide (NO) and auxin in Cd-mediated inhibition of Arabidopsis thaliana root meristem growth. Our study demonstrated that in the first 12 h of exposure, Cd inhibits primary root elongation through a decrease in the sizes of both the elongation and meristematic zones. Following Cd exposure, a decrease in auxin levels is associated with reduced PIN1/3/7 protein accumulation, but not with reduced PIN1/3/7 transcript levels. Additionally, Cd stabilized AXR3/IAA17 protein to repress auxin signalling in this Cd-mediated process. Furthermore, decreasing Cd-induced NO accumulation with either NO-specific scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO) or NO synthase inhibitor N(ω) -nitro-l-Arg-methylester (l-NAME) compromised the Cd-mediated inhibition of root meristem development, reduction in auxin and PIN1/3/7 accumulation, as well as stabilization of AXR3/IAA17, indicating that NO participates in Cd-mediated inhibition of root meristem growth. Taken together, our data suggest that Cd inhibits root meristem growth by NO-mediated repression of auxin accumulation and signalling in Arabidopsis.

  1. Inhibition of growth of Toxoplasma gondii in cultured fibroblasts by human recombinant gamma interferon.

    PubMed Central

    Pfefferkorn, E R; Guyre, P M

    1984-01-01

    The growth of Toxoplasma gondii in cultured human fibroblasts was inhibited by recombinant human gamma interferon at concentrations of 8 to 16 U/ml. The interferon was titrated by observing a total inhibition of parasite plaque formation 7 days after infection. Inhibition of the growth of T. gondii in the early days after infection was measured by marked reductions in the incorporation of radioactive uracil, a precursor that can only be used by the parasites. This assay showed that when cells were pretreated with gamma interferon for 1 day and then infected, inhibition of T. gondii growth could be readily detected 1 or 2 days after infection. When the pretreatment was omitted and parasites and gamma interferon were added at the same time, no inhibition of parasite growth could be detected 1 day later, although it was apparent after 2 days. Cultures from which the gamma interferon had been removed by washing after a 1-day treatment showed inhibition of T. gondii growth. Gamma interferon had no effect on the viability of extracellular parasites, but it did inhibit the synthesis of host cell RNA and protein by ca. 50% 3 days after treatment. This degree of inhibition is unlikely, of itself, to compromise the growth of T. gondii. Recombinant alpha and beta interferons had no effect on the growth of T. gondii. Images PMID:6425215

  2. The microbiome of medicinal plants: diversity and importance for plant growth, quality and health.

    PubMed

    Köberl, Martina; Schmidt, Ruth; Ramadan, Elshahat M; Bauer, Rudolf; Berg, Gabriele

    2013-12-20

    Past medicinal plant research primarily focused on bioactive phytochemicals, however, the focus is currently shifting due to the recognition that a significant number of phytotherapeutic compounds are actually produced by associated microbes or through interaction with their host. Medicinal plants provide an enormous bioresource of potential use in modern medicine and agriculture, yet their microbiome is largely unknown. The objective of this review is (i) to introduce novel insights into the plant microbiome with a focus on medicinal plants, (ii) to provide details about plant- and microbe-derived ingredients of medicinal plants, and (iii) to discuss possibilities for plant growth promotion and plant protection for commercial cultivation of medicinal plants. In addition, we also present a case study performed both to analyse the microbiome of three medicinal plants (Matricaria chamomilla L., Calendula officinalis L., and Solanum distichum Schumach. and Thonn.) cultivated on organically managed Egyptian desert farm and to develop biological control strategies. The soil microbiome of the desert ecosystem was comprised of a high abundance of Gram-positive bacteria of prime importance for pathogen suppression under arid soil conditions. For all three plants, we observed a clearly plant-specific selection of the microbes as well as highly specific diazotrophic communities that overall identify plant species as important drivers in structural and functional diversity. Lastly, native Bacillus spec. div. strains were able to promote plant growth and elevate the plants' flavonoid production. These results underline the numerous links between the plant-associated microbiome and the plant metabolome.

  3. Magnetic field effects on plant growth, development, and evolution

    PubMed Central

    Maffei, Massimo E.

    2014-01-01

    The geomagnetic field (GMF) is a natural component of our environment. Plants, which are known to sense different wavelengths of light, respond to gravity, react to touch and electrical signaling, cannot escape the effect of GMF. While phototropism, gravitropism, and tigmotropism have been thoroughly studied, the impact of GMF on plant growth and development is not well-understood. This review describes the effects of altering magnetic field (MF) conditions on plants by considering plant responses to MF values either lower or higher than those of the GMF. The possible role of GMF on plant evolution and the nature of the magnetoreceptor is also discussed. PMID:25237317

  4. Plant Growth and Morphogenesis under Different Gravity Conditions: Relevance to Plant Life in Space.

    PubMed

    Hoson, Takayuki

    2014-05-16

    The growth and morphogenesis of plants are entirely dependent on the gravitational acceleration of earth. Under microgravity conditions in space, these processes are greatly modified. Recent space experiments, in combination with ground-based studies, have shown that elongation growth is stimulated and lateral expansion suppressed in various shoot organs and roots under microgravity conditions. Plant organs also show automorphogenesis in space, which consists of altered growth direction and spontaneous curvature in the dorsiventral (back and front) directions. Changes in cell wall properties are responsible for these modifications of growth and morphogenesis under microgravity conditions. Plants live in space with interesting new sizes and forms.

  5. Small molecules inhibit growth, viability and ergosterol biosynthesis in Candida albicans.

    PubMed

    Rajput, Sandeep B; Karuppayil, S Mohan

    2013-12-01

    The aim of this work was to evaluate the anti-Candida efficacy of twenty five molecules of plant origin. Based on their MICs, effective molecules were categorized into four categories. Susceptibility testing of test compounds was carried out by standard methodology (M27-A2) as per CLSI guidelines. Minimum Fungicidal Concentration (MFC) was determined as the lowest concentration of drug killing 99.9% cells. Effect on sterol profile was evaluated by sterol quantitation method. Among the screened molecules, cinnamaldehyde, piperidine, citral, furfuraldehyde and indole were potent inhibitors of growth and viability. Exposure of Candida cells to cinnamaldehyde, piperidine, citral, furfuraldehyde, indole, α- and β- pinene at MIC's, altered ergosterol profile. Our results indicate that the molecules altering sterol profile may exert their antifungal effect through inhibition of ergosterol biosynthesis and could be good candidates for fungal specific drug development. PMID:23449869

  6. Selective inhibition of growth-related gene expression in murine keratinocytes by transforming growth factor beta.

    PubMed Central

    Coffey, R J; Bascom, C C; Sipes, N J; Graves-Deal, R; Weissman, B E; Moses, H L

    1988-01-01

    Transforming growth factor beta (TGF beta) is a potent inhibitor of epithelial cell proliferation. A nontumorigenic epidermal growth factor (EGF)-dependent epithelial cell line, BALB/MK, is reversibly growth arrested by TGF beta. TGF beta will also abrogate EGF-stimulated mitogenesis of quiescent BALB/MK cells. Increased levels of calcium (greater than 1.0 mM) will induce differentiation in BALB/MK cells; in contrast, TGF beta-mediated growth inhibition does not result in induction of terminal differentiation. In the present study, the effects of TGF beta and calcium on growth factor-inducible gene expression were examined. TGF beta markedly decreased c-myc and KC gene expression in rapidly growing BALB/MK cells and reduced the EGF induction of c-myc and KC in a quiescent population of cells. TGF beta exerted its control over c-myc expression at a posttranscriptional level, and this inhibitory effect was dependent on protein synthesis. TGF beta had no effect on c-fos gene expression, whereas 1.5 mM calcium attenuated EGF-induced c-fos expression in quiescent cells. Expression of beta-actin, however, was slightly increased in both rapidly growing and EGF-restimulated quiescent BALB/MK cells treated with TGF beta. Thus, in this system, TGF beta selectively reduced expression of certain genes associated with cell proliferation (c-myc and KC), and at least part of the TGF beta effect was at a posttranscriptional level. Images PMID:2463471

  7. Growth, nitrogen uptake and flow in maize plants affected by root growth restriction.

    PubMed

    Xu, Liangzheng; Niu, Junfang; Li, Chunjian; Zhang, Fusuo

    2009-07-01

    The objective of the present study was to investigate the influence of a reduced maize root-system size on root growth and nitrogen (N) uptake and flow within plants. Restriction of shoot-borne root growth caused a strong decrease in the absorption of root: shoot dry weight ratio and a reduction in shoot growth. On the other hand, compensatory growth and an increased N uptake rate in the remaining roots were observed. Despite the limited long-distance transport pathway in the mesocotyl with restriction of shoot-borne root growth, N cycling within these plants was higher than those in control plants, implying that xylem and phloem flow velocities via the mesocotyl were considerably higher than in plants with an intact root system. The removal of the seminal roots in addition to restricting shoot-borne root development did not affect whole plant growth and N uptake, except for the stronger compensatory growth of the primary roots. Our results suggest that an adequate N supply to maize plant is maintained by compensatory growth of the remaining roots, increased N uptake rate and flow velocities within the xylem and phloem via the mesocotyl, and reduction in the shoot growth rate.

  8. Altered Glycine Decarboxylation Inhibition in Isonicotinic Acid Hydrazide-Resistant Mutant Callus Lines and in Regenerated Plants and Seed Progeny

    PubMed Central

    Zelitch, Israel; Berlyn, Mary B.

    1982-01-01

    Isonicotinic acid hydrazide (INH), an inhibitor of the photorespiratory pathway blocking the conversion of glycine to serine and CO2, has been used as a selective agent to obtain INH-resistant tobacco (Nicotiana tabacum) callus cells. Of 22 cell lines that were INH-resistant, none were different from wild-type cells in their ability to take up [3H]INH or to oxidize INH to isonicotinic acid. In 7 of the 22 cell lines, INH resistance was associated with decreased inhibition of NAD-dependent glycine decarboxylation activity in isolated mitochondrial preparations. In the cell line that was most extensively investigated (I 24), this biochemical phenotype (exhibiting a 3-fold higher Ki with INH) was observed in leaf mitochondria of regenerated plants and of plants produced from them by self-fertilization. After crosses between resistant and sensitive plants, the decreased inhibition of glycine decarboxylation was observed among F2 and backcross progeny only in those plants previously identified as INH-resistant by callus growth tests. In contrast, in siblings identified as INH-sensitive, glycine decarboxylation was inhibited by INH at the wild-type level. This demonstration of the transfer of an altered enzyme property from callus to regenerated plants and through seed progeny fulfills an important requirement for the use of somatic cell genetics to produce biochemical mutants of higher plants. PMID:16662158

  9. Multiscale Models in the Biomechanics of Plant Growth

    PubMed Central

    Fozard, John A.

    2015-01-01

    Plant growth occurs through the coordinated expansion of tightly adherent cells, driven by regulated softening of cell walls. It is an intrinsically multiscale process, with the integrated properties of multiple cell walls shaping the whole tissue. Multiscale models encode physical relationships to bring new understanding to plant physiology and development. PMID:25729061

  10. Brassinosteroid-induced exaggerated growth in hydroponically grown Arabidopsis plants.

    PubMed

    Arteca, Jeannette M.; Arteca, Richard N.

    2001-05-01

    The effects of root application of brassinolide (BL) on the growth and development of Arabidopsis plants (Arabidopsis thaliana ecotype Columbia [L.] Heynh) were evaluated. Initially, all leaves were evaluated on plants 18, 22, 26 and 29 days old. The younger leaves were found to exhibit maximal petiole elongation and upward leaf bending in response to BL treatment. Therefore, based on these results leaves 6, 7 and 8 on 22-24-day-old plants were selected for all subsequent studies. Elongation along the length of the petiole in response to BL treatment was uniform with the exception of an approximately 4 mm region next to the leaf where upward curvature was observed. Both BL and 24-epibrassinolide (24-epiBL) were evaluated, with BL being more effective at lower concentrations than 24-epiBL. The exaggerated growth induced by 0.1 µM BL was not observed in plants treated with 1 000-fold higher concentrations of GA3, IAA, NAA or 2,4-D (100 µM). In addition, no exaggerated growth effects were observed when plants were treated with 200 ppm ethylene or 1 mM ACC. All treatments with BL, NAA, 2,4-D, IAA or ACC promoted ethylene and ACC production in wild type Arabidopsis plants, but only BL triggered exaggerated plant growth. BL also promoted exaggerated growth and elevated levels of ACC and ethylene in the ethylene insensitive mutant etr1-3, showing that the effect of BR on growth is independent of ethylene. This work provides evidence that BR-induced exaggerated growth of Arabidopsis plants is independent of gibberellins, auxins and ethylene.

  11. The microbiome of medicinal plants: diversity and importance for plant growth, quality and health

    PubMed Central

    Köberl, Martina; Schmidt, Ruth; Ramadan, Elshahat M.; Bauer, Rudolf; Berg, Gabriele

    2013-01-01

    Past medicinal plant research primarily focused on bioactive phytochemicals, however, the focus is currently shifting due to the recognition that a significant number of phytotherapeutic compounds are actually produced by associated microbes or through interaction with their host. Medicinal plants provide an enormous bioresource of potential use in modern medicine and agriculture, yet their microbiome is largely unknown. The objective of this review is (i) to introduce novel insights into the plant microbiome with a focus on medicinal plants, (ii) to provide details about plant- and microbe-derived ingredients of medicinal plants, and (iii) to discuss possibilities for plant growth promotion and plant protection for commercial cultivation of medicinal plants. In addition, we also present a case study performed both to analyse the microbiome of three medicinal plants (Matricaria chamomilla L., Calendula officinalis L., and Solanum distichum Schumach. and Thonn.) cultivated on organically managed Egyptian desert farm and to develop biological control strategies. The soil microbiome of the desert ecosystem was comprised of a high abundance of Gram-positive bacteria of prime importance for pathogen suppression under arid soil conditions. For all three plants, we observed a clearly plant-specific selection of the microbes as well as highly specific diazotrophic communities that overall identify plant species as important drivers in structural and functional diversity. Lastly, native Bacillus spec. div. strains were able to promote plant growth and elevate the plants’ flavonoid production. These results underline the numerous links between the plant-associated microbiome and the plant metabolome. PMID:24391634

  12. Atmosphere control for plant growth flight experiments

    NASA Technical Reports Server (NTRS)

    Powell, Ferolyn T.; Sudar, Martin; Timm, Marc; Yost, Bruce

    1989-01-01

    An atmosphere exchange system (AES) has been designed to provide a conditioned atmosphere supply to plant specimens in flight without incurring the large weight and volume associated with bottled gases. The paper examines the atmosphere filter cartridge (AFC) designed to remove trace organic atmosphere contaminants from the Space Shuttle cabin and to condition the cabin atmosphere prior to exposure to plant specimens. The AES and AFC are described and illustrated. The AFC design requirements are discussed and results are presented from tests on the performance of the AFC. Also, consideration is given to the potential applications of the AFC and future design concepts for atmosphere control.

  13. Ginseng saponin metabolite 20(S)-protopanaxadiol inhibits tumor growth by targeting multiple cancer signaling pathways

    PubMed Central

    GAO, JIAN-LI; LV, GUI-YUAN; HE, BAI-CHENG; ZHANG, BING-QIANG; ZHANG, HONGYU; WANG, NING; WANG, CHONG-ZHI; DU, WEI; YUAN, CHUN-SU; HE, TONG-CHUAN

    2013-01-01

    Plant-derived active constituents and their semi-synthetic or synthetic analogs have served as major sources of anticancer drugs. 20(S)-protopanaxadiol (PPD) is a metabolite of ginseng saponin of both American ginseng (Panax quinquefolius L.) and Asian ginseng (Panax ginseng C.A. Meyer). We previously demonstrated that ginsenoside Rg3, a glucoside precursor of PPD, exhibits anti-proliferative effects on HCT116 cells and reduces tumor size in a xenograft model. Our subsequent study indicated that PPD has more potent antitumor activity than that of Rg3 in vitro although the mechanism underlying the anticancer activity of PPD remains to be defined. Here, we investigated the mechanism underlying the anticancer activity of PPD in human cancer cells in vitro and in vivo. PPD was shown to inhibit growth and induce cell cycle arrest in HCT116 cells. The in vivo studies indicate that PPD inhibits xenograft tumor growth in athymic nude mice bearing HCT116 cells. The xenograft tumor size was significantly reduced when the animals were treated with PPD (30 mg/kg body weight) for 3 weeks. When the expression of previously identified Rg3 targets, A kinase (PRKA) anchor protein 8 (AKAP8L) and phosphatidylinositol transfer protein α (PITPNA), was analyzed, PPD was shown to inhibit the expression of PITPNA while upregulating AKAP8L expression in HCT116 cells. Pathway-specific reporter assays indicated that PPD effectively suppressed the NF-κB, JNK and MAPK/ERK signaling pathways. Taken together, our results suggest that the anticancer activity of PPD in colon cancer cells may be mediated through targeting NF-κB, JNK and MAPK/ERK signaling pathways, although the detailed mechanisms underlying the anticancer mode of PPD action need to be fully elucidated. PMID:23633038

  14. A chrysin derivative suppresses skin cancer growth by inhibiting cyclin-dependent kinases.

    PubMed

    Liu, Haidan; Liu, Kangdong; Huang, Zunnan; Park, Chan-Mi; Thimmegowda, N R; Jang, Jae-Hyuk; Ryoo, In-Ja; He, Long; Kim, Sun-Ok; Oi, Naomi; Lee, Ki Won; Soung, Nak-Kyun; Bode, Ann M; Yang, Yifeng; Zhou, Xinmin; Erikson, Raymond L; Ahn, Jong-Seog; Hwang, Joonsung; Kim, Kyoon Eon; Dong, Zigang; Kim, Bo-Yeon

    2013-09-01

    Chrysin (5,7-dihydroxyflavone), a natural flavonoid widely distributed in plants, reportedly has chemopreventive properties against various cancers. However, the anticancer activity of chrysin observed in in vivo studies has been disappointing. Here, we report that a chrysin derivative, referred to as compound 69407, more strongly inhibited EGF-induced neoplastic transformation of JB6 P(+) cells compared with chrysin. It attenuated cell cycle progression of EGF-stimulated cells at the G1 phase and inhibited the G1/S transition. It caused loss of retinoblastoma phosphorylation at both Ser-795 and Ser-807/811, the preferred sites phosphorylated by Cdk4/6 and Cdk2, respectively. It also suppressed anchorage-dependent and -independent growth of A431 human epidermoid carcinoma cells. Compound 69407 reduced tumor growth in the A431 mouse xenograft model and retinoblastoma phosphorylation at Ser-795 and Ser-807/811. Immunoprecipitation kinase assay results showed that compound 69407 attenuated endogenous Cdk4 and Cdk2 kinase activities in EGF-stimulated JB6 P(+) cells. Pulldown and in vitro kinase assay results indicated that compound 69407 directly binds with Cdk2 and Cdk4 in an ATP-independent manner and inhibited their kinase activities. A binding model between compound 69407 and a crystal structure of Cdk2 predicted that compound 69407 was located inside the Cdk2 allosteric binding site. The binding was further verified by a point mutation binding assay. Overall results indicated that compound 69407 is an ATP-noncompetitive cyclin-dependent kinase inhibitor with anti-tumor effects, which acts by binding inside the Cdk2 allosteric pocket. This study provides new insights for creating a general pharmacophore model to design and develop novel ATP-noncompetitive agents with chemopreventive or chemotherapeutic potency.

  15. A chrysin derivative suppresses skin cancer growth by inhibiting cyclin-dependent kinases.

    PubMed

    Liu, Haidan; Liu, Kangdong; Huang, Zunnan; Park, Chan-Mi; Thimmegowda, N R; Jang, Jae-Hyuk; Ryoo, In-Ja; He, Long; Kim, Sun-Ok; Oi, Naomi; Lee, Ki Won; Soung, Nak-Kyun; Bode, Ann M; Yang, Yifeng; Zhou, Xinmin; Erikson, Raymond L; Ahn, Jong-Seog; Hwang, Joonsung; Kim, Kyoon Eon; Dong, Zigang; Kim, Bo-Yeon

    2013-09-01

    Chrysin (5,7-dihydroxyflavone), a natural flavonoid widely distributed in plants, reportedly has chemopreventive properties against various cancers. However, the anticancer activity of chrysin observed in in vivo studies has been disappointing. Here, we report that a chrysin derivative, referred to as compound 69407, more strongly inhibited EGF-induced neoplastic transformation of JB6 P(+) cells compared with chrysin. It attenuated cell cycle progression of EGF-stimulated cells at the G1 phase and inhibited the G1/S transition. It caused loss of retinoblastoma phosphorylation at both Ser-795 and Ser-807/811, the preferred sites phosphorylated by Cdk4/6 and Cdk2, respectively. It also suppressed anchorage-dependent and -independent growth of A431 human epidermoid carcinoma cells. Compound 69407 reduced tumor growth in the A431 mouse xenograft model and retinoblastoma phosphorylation at Ser-795 and Ser-807/811. Immunoprecipitation kinase assay results showed that compound 69407 attenuated endogenous Cdk4 and Cdk2 kinase activities in EGF-stimulated JB6 P(+) cells. Pulldown and in vitro kinase assay results indicated that compound 69407 directly binds with Cdk2 and Cdk4 in an ATP-independent manner and inhibited their kinase activities. A binding model between compound 69407 and a crystal structure of Cdk2 predicted that compound 69407 was located inside the Cdk2 allosteric binding site. The binding was further verified by a point mutation binding assay. Overall results indicated that compound 69407 is an ATP-noncompetitive cyclin-dependent kinase inhibitor with anti-tumor effects, which acts by binding inside the Cdk2 allosteric pocket. This study provides new insights for creating a general pharmacophore model to design and develop novel ATP-noncompetitive agents with chemopreventive or chemotherapeutic potency. PMID:23888052

  16. Terpenoids of plant origin inhibit morphogenesis, adhesion, and biofilm formation by Candida albicans.

    PubMed

    Raut, Jayant S; Shinde, Ravikumar B; Chauhan, Nitin M; Karuppayil, S Mohan

    2013-01-01

    Biofilm-related infections caused by Candida albicans and associated drug resistant micro-organisms are serious problems for immunocompromised populations. Molecules which can prevent or remove biofilms are needed. Twenty-eight terpenoids of plant origin were analysed for their activity against growth, virulence attributes, and biofilms of C. albicans. Eighteen molecules exhibited minimum inhibitory concentrations of <2 mg ml(-1) for planktonic growth. Selected molecules inhibited yeast to hyphal dimorphism at low concentrations (0.031-0.5 mg ml(-1)), while adhesion to a solid surface was prevented at 0.5-2 mg ml(-1). Treatment with 14 terpenoids resulted in significant (p < 0.05) inhibition of biofilm formation, and of these, linalool, nerol, isopulegol, menthol, carvone, α-thujone, and farnesol exhibited biofilm-specific activity. Eight terpenoids were identified as inhibitors of mature biofilms. This study demonstrated the antibiofilm potential of terpenoids, which need to be further explored as therapeutic strategy against biofilm associated infections of C. albicans. PMID:23216018

  17. [Plant growth with limited water]. [Annual report, December 15, 1992--December 14, 1993

    SciTech Connect

    Not Available

    1993-12-01

    We used a soybean seedling system to explore the mechanism of growth limitation by water deficiency (low {Psi}{sub W}). Our prior work had show that (low {Psi}{sub W} inhibited plant growth initially because of a physical limitation to water uptake that appeared to result from a decrease in the {Psi}{sub W} gradient feeding water to the enlarging cells. The gradient was shown to originate from cell wall yielding and was altered primarily at the vascular tissue. In the present grant, we reported the detailed shape of the gradient. We also found that growth could mobilize water from mature tissues in the complete absence of external water using the gradient in {Psi}{sub W}. Growth was maintained by this mobilization. After growth has been inhibited a few hours, metabolic changes occur and a 28kD protein accumulates in the wall fraction of the growth-affected cells. In the present grant, we showed that the mRNA for the protein accumulated in a tissue-specific manner similar to that of the protein, and the accumulation was correlated with the growth response. Other investigators working independently with an acid phosphatase found a deduced amino acid sequence similar to that for the 28kD protein we had published. Biochemical tests showed that the 28kD protein and a related 3lkD protein expressed acid phosphatase activity. We found that the acid phosphatase Of the 28kD protein was in the cell walls of intact plants (in addition to being in the cytoplasm). Current work focuses on the role of this protein. Efforts were made to reverse the growth inhibition at low {Phi}{sub W} by treating growing tissues with low pH buffer, but the protons apparently failed to penetrate the cuticle.

  18. Factors affecting plant growth in membrane nutrient delivery

    NASA Technical Reports Server (NTRS)

    Dreschel, T. W.; Wheeler, R. M.; Sager, J. C.; Knott, W. M.

    1990-01-01

    The development of the tubular membrane plant growth unit for the delivery of water and nutrients to roots in microgravity has recently focused on measuring the effects of changes in physical variables controlling solution availability to the plants. Significant effects of membrane pore size and the negative pressure used to contain the solution were demonstrated. Generally, wheat grew better in units with a larger pore size but equal negative pressure and in units with the same pore size but less negative pressure. Lettuce also exhibited better plant growth at less negative pressure.

  19. Material and methods to increase plant growth and yield

    DOEpatents

    Kirst, Matias

    2015-09-15

    The present invention relates to materials and methods for modulating growth rates, yield, and/or resistance to drought conditions in plants. In one embodiment, a method of the invention comprises increasing expression of an hc1 gene (or a homolog thereof that provides for substantially the same activity), or increasing expression or activity of the protein encoded by an hc1 gene thereof, in a plant, wherein expression of the hc1 gene or expression or activity of the protein encoded by an hc1 gene results in increased growth rate, yield, and/or drought resistance in the plant.

  20. Poly(ADP-Ribose)Polymerase Activity Controls Plant Growth by Promoting Leaf Cell Number

    PubMed Central

    Schulz, Philipp; Jansseune, Karel; Degenkolbe, Thomas; Méret, Michaël; Claeys, Hannes; Skirycz, Aleksandra; Teige, Markus; Willmitzer, Lothar; Hannah, Matthew A.

    2014-01-01

    A changing global environment, rising population and increasing demand for biofuels are challenging agriculture and creating a need for technologies to increase biomass production. Here we demonstrate that the inhibition of poly (ADP-ribose) polymerase activity is a promising technology to achieve this under non-stress conditions. Furthermore, we investigate the basis of this growth enhancement via leaf series and kinematic cell analysis as well as single leaf transcriptomics and plant metabolomics under non-stress conditions. These data indicate a regulatory function of PARP within cell growth and potentially development. PARP inhibition enhances growth of Arabidopsis thaliana by enhancing the cell number. Time course single leaf transcriptomics shows that PARP inhibition regulates a small subset of genes which are related to growth promotion, cell cycle and the control of metabolism. This is supported by metabolite analysis showing overall changes in primary and particularly secondary metabolism. Taken together the results indicate a versatile function of PARP beyond its previously reported roles in controlling plant stress tolerance and thus can be a useful target for enhancing biomass production. PMID:24587323

  1. Design and construction of an inexpensive homemade plant growth chamber.

    PubMed

    Katagiri, Fumiaki; Canelon-Suarez, Dario; Griffin, Kelsey; Petersen, John; Meyer, Rachel K; Siegle, Megan; Mase, Keisuke

    2015-01-01

    Plant growth chambers produce controlled environments, which are crucial in making reproducible observations in experimental plant biology research. Commercial plant growth chambers can provide precise controls of environmental parameters, such as temperature, humidity, and light cycle, and the capability via complex programming to regulate these environmental parameters. But they are expensive. The high cost of maintaining a controlled growth environment is often a limiting factor when determining experiment size and feasibility. To overcome the limitation of commercial growth chambers, we designed and constructed an inexpensive plant growth chamber with consumer products for a material cost of $2,300. For a comparable growth space, a commercial plant growth chamber could cost $40,000 or more. Our plant growth chamber had outside dimensions of 1.5 m (W) x 1.8 m (D) x 2 m (H), providing a total growth area of 4.5 m2 with 40-cm high clearance. The dimensions of the growth area and height can be flexibly changed. Fluorescent lights with large reflectors provided a relatively spatially uniform photosynthetically active radiation intensity of 140-250 μmoles/m2/sec. A portable air conditioner provided an ample cooling capacity, and a cooling water mister acted as a powerful humidifier. Temperature, relative humidity, and light cycle inside the chamber were controlled via a z-wave home automation system, which allowed the environmental parameters to be monitored and programmed through the internet. In our setting, the temperature was tightly controlled: 22.2°C±0.8°C. The one-hour average relative humidity was maintained at 75%±7% with short spikes up to ±15%. Using the interaction between Arabidopsis and one of its bacterial pathogens as a test experimental system, we demonstrate that experimental results produced in our chamber were highly comparable to those obtained in a commercial growth chamber. In summary, our design of an inexpensive plant growth chamber

  2. Design and Construction of an Inexpensive Homemade Plant Growth Chamber

    PubMed Central

    Katagiri, Fumiaki; Canelon-Suarez, Dario; Griffin, Kelsey; Petersen, John; Meyer, Rachel K.; Siegle, Megan; Mase, Keisuke

    2015-01-01

    Plant growth chambers produce controlled environments, which are crucial in making reproducible observations in experimental plant biology research. Commercial plant growth chambers can provide precise controls of environmental parameters, such as temperature, humidity, and light cycle, and the capability via complex programming to regulate these environmental parameters. But they are expensive. The high cost of maintaining a controlled growth environment is often a limiting factor when determining experiment size and feasibility. To overcome the limitation of commercial growth chambers, we designed and constructed an inexpensive plant growth chamber with consumer products for a material cost of $2,300. For a comparable growth space, a commercial plant growth chamber could cost $40,000 or more. Our plant growth chamber had outside dimensions of 1.5 m (W) x 1.8 m (D) x 2 m (H), providing a total growth area of 4.5 m2 with 40-cm high clearance. The dimensions of the growth area and height can be flexibly changed. Fluorescent lights with large reflectors provided a relatively spatially uniform photosynthetically active radiation intensity of 140–250 μmoles/m2/sec. A portable air conditioner provided an ample cooling capacity, and a cooling water mister acted as a powerful humidifier. Temperature, relative humidity, and light cycle inside the chamber were controlled via a z-wave home automation system, which allowed the environmental parameters to be monitored and programmed through the internet. In our setting, the temperature was tightly controlled: 22.2°C±0.8°C. The one-hour average relative humidity was maintained at 75%±7% with short spikes up to ±15%. Using the interaction between Arabidopsis and one of its bacterial pathogens as a test experimental system, we demonstrate that experimental results produced in our chamber were highly comparable to those obtained in a commercial growth chamber. In summary, our design of an inexpensive plant growth chamber

  3. Design and construction of an inexpensive homemade plant growth chamber.

    PubMed

    Katagiri, Fumiaki; Canelon-Suarez, Dario; Griffin, Kelsey; Petersen, John; Meyer, Rachel K; Siegle, Megan; Mase, Keisuke

    2015-01-01

    Plant growth chambers produce controlled environments, which are crucial in making reproducible observations in experimental plant biology research. Commercial plant growth chambers can provide precise controls of environmental parameters, such as temperature, humidity, and light cycle, and the capability via complex programming to regulate these environmental parameters. But they are expensive. The high cost of maintaining a controlled growth environment is often a limiting factor when determining experiment size and feasibility. To overcome the limitation of commercial growth chambers, we designed and constructed an inexpensive plant growth chamber with consumer products for a material cost of $2,300. For a comparable growth space, a commercial plant growth chamber could cost $40,000 or more. Our plant growth chamber had outside dimensions of 1.5 m (W) x 1.8 m (D) x 2 m (H), providing a total growth area of 4.5 m2 with 40-cm high clearance. The dimensions of the growth area and height can be flexibly changed. Fluorescent lights with large reflectors provided a relatively spatially uniform photosynthetically active radiation intensity of 140-250 μmoles/m2/sec. A portable air conditioner provided an ample cooling capacity, and a cooling water mister acted as a powerful humidifier. Temperature, relative humidity, and light cycle inside the chamber were controlled via a z-wave home automation system, which allowed the environmental parameters to be monitored and programmed through the internet. In our setting, the temperature was tightly controlled: 22.2°C±0.8°C. The one-hour average relative humidity was maintained at 75%±7% with short spikes up to ±15%. Using the interaction between Arabidopsis and one of its bacterial pathogens as a test experimental system, we demonstrate that experimental results produced in our chamber were highly comparable to those obtained in a commercial growth chamber. In summary, our design of an inexpensive plant growth chamber

  4. Olive oil compounds inhibit vascular endothelial growth factor receptor-2 phosphorylation

    SciTech Connect

    Lamy, Sylvie Ouanouki, Amira; Béliveau, Richard; Desrosiers, Richard R.

    2014-03-10

    Vascular endothelial growth factor (VEGF) triggers crucial signaling processes that regulate tumor angiogenesis and, therefore, represents an attractive target for the development of novel anticancer therapeutics. Several epidemiological studies have confirmed that abundant consumption of foods from plant origin is associated with reduced risk of developing cancers. In the Mediterranean basin, the consumption of extra virgin olive oil is an important constituent of the diet. Compared to other vegetable oils, the presence of several phenolic antioxidants in olive oil is believed to prevent the occurrence of a variety of pathological processes, such as cancer. While the strong antioxidant potential of these molecules is well characterized, their antiangiogenic activities remain unknown. The aim of this study is to investigate whether tyrosol (Tyr), hydroxytyrosol (HT), taxifolin (Tax), oleuropein (OL) and oleic acid (OA), five compounds contained in extra virgin olive oil, can affect in vitro angiogenesis. We found that HT, Tax and OA were the most potent angiogenesis inhibitors through their inhibitory effect on specific autophosphorylation sites of VEGFR-2 (Tyr951, Tyr1059, Tyr1175 and Tyr1214) leading to the inhibition of endothelial cell (EC) signaling. Inhibition of VEGFR-2 by these olive oil compounds significantly reduced VEGF-induced EC proliferation and migration as well as their morphogenic differentiation into capillary-like tubular structures in Matrigel. Our study demonstrates that HT, Tax and OA are novel and potent inhibitors of the VEGFR-2 signaling pathway. These findings emphasize the chemopreventive properties of olive oil and highlight the importance of nutrition in cancer prevention. - Highlights: • We investigated five compounds contained in extra virgin olive oil on angiogenesis. • Hydroxytyrosol, taxifolin and oleic acid are the best angiogenesis inhibitors. • Olive oil compounds affect endothelial cell functions essential for

  5. Plant Growth-Promoting Bacteria for Phytostabilization of Mine Tailings

    SciTech Connect

    Grandlic, C.J.; Mendez, M.O.; Chorover, J.; Machado, B.; Maier, R.M.

    2009-05-19

    Eolian dispersion of mine tailings in arid and semiarid environments is an emerging global issue for which economical remediation alternatives are needed. Phytostabilization, the revegetation of these sites with native plants, is one such alternative. Revegetation often requires the addition of bulky amendments such as compost which greatly increases cost. We report the use of plant growth-promoting bacteria (PGPB) to enhance the revegetation of mine tailings and minimize the need for compost amendment. Twenty promising PGPB isolates were used as seed inoculants in a series of greenhouse studies to examine revegetation of an extremely acidic, high metal content tailings sample previously shown to require 15% compost amendment for normal plant growth. Several isolates significantly enhanced growth of two native species, quailbush and buffalo grass, in tailings. In this study, PGPB/compost outcomes were plant specific; for quailbush, PGPB were most effective in combination with 10% compost addition while for buffalo grass, PGPB enhanced growth in the complete absence of compost. Results indicate that selected PGPB can improve plant establishment and reduce the need for compost amendment. Further, PGPB activities necessary for aiding plant growth in mine tailings likely include tolerance to acidic pH and metals.

  6. Plant growth-promoting bacteria for phytostabilization of mine tailings.

    PubMed

    Grandlic, Christopher J; Mendez, Monica O; Chorover, Jon; Machado, Blenda; Maier, Raina M

    2008-03-15

    Eolian dispersion of mine tailings in arid and semiarid environments is an emerging global issue for which economical remediation alternatives are needed. Phytostabilization, the revegetation of these sites with native plants, is one such alternative. Revegetation often requires the addition of bulky amendments such as compost which greatly increases cost. We report the use of plant growth-promoting bacteria (PGPB) to enhance the revegetation of mine tailings and minimize the need for compost amendment. Twenty promising PGPB isolates were used as seed inoculants in a series of greenhouse studies to examine revegetation of an extremely acidic, high metal contenttailings sample previously shown to require 15% compost amendment for normal plant growth. Several isolates significantly enhanced growth of two native species, quailbush and buffalo grass, in tailings. In this study, PGPB/compost outcomes were plant specific; for quailbush, PGPB were most effective in combination with 10% compost addition while for buffalo grass, PGPB enhanced growth in the complete absence of compost. Results indicate that selected PGPB can improve plant establishment and reduce the need for compost amendment. Further, PGPB activities necessary for aiding plant growth in mine tailings likely include tolerance to acidic pH and metals.

  7. The role of microbial signals in plant growth and development.

    PubMed

    Ortíz-Castro, Randy; Contreras-Cornejo, Hexon Angel; Macías-Rodríguez, Lourdes; López-Bucio, José

    2009-08-01

    Plant growth and development involves a tight coordination of the spatial and temporal organization of cell division, cell expansion and cell differentiation. Orchestration of these events requires the exchange of signaling molecules between the root and shoot, which can be affected by both biotic and abiotic factors. The interactions that occur between plants and their associated microorganisms have long been of interest, as knowledge of these processes could lead to the development of novel agricultural applications. Plants produce a wide range of organic compounds including sugars, organic acids and vitamins, which can be used as nutrients or signals by microbial populations. On the other hand, microorganisms release phytohormones, small molecules or volatile compounds, which may act directly or indirectly to activate plant immunity or regulate plant growth and morphogenesis. In this review, we focus on recent developments in the identification of signals from free-living bacteria and fungi that interact with plants in a beneficial way. Evidence has accumulated indicating that classic plant signals such as auxins and cytokinins can be produced by microorganisms to efficiently colonize the root and modulate root system architecture. Other classes of signals, including N-acyl-L-homoserine lactones, which are used by bacteria for cell-to-cell communication, can be perceived by plants to modulate gene expression, metabolism and growth. Finally, we discuss the role played by volatile organic compounds released by certain plant growth-promoting rhizobacteria in plant immunity and developmental processes. The picture that emerges is one in which plants and microbes communicate themselves through transkingdom signaling systems involving classic and novel signals.

  8. The role of microbial signals in plant growth and development

    PubMed Central

    Ortíz-Castro, Randy; Contreras-Cornejo, Hexon Angel; Macías-Rodríguez, Lourdes

    2009-01-01

    Plant growth and development involves a tight coordination of the spatial and temporal organization of cell division, cell expansion and cell differentiation. Orchestration of these events requires the exchange of signaling molecules between the root and shoot, which can be affected by both biotic and abiotic factors. The interactions that occur between plants and their associated microorganisms have long been of interest, as knowledge of these processes could lead to the development of novel agricultural applications. Plants produce a wide range of organic compounds including sugars, organic acids and vitamins, which can be used as nutrients or signals by microbial populations. On the other hand, microorganisms release phytohormones, small molecules or volatile compounds, which may act directly or indirectly to activate plant immunity or regulate plant growth and morphogenesis. In this review, we focus on recent developments in the identification of signals from free-living bacteria and fungi that interact with plants in a beneficial way. Evidence has accumulated indicating that classic plant signals such as auxins and cytokinins can be produced by microorganisms to efficiently colonize the root and modulate root system architecture. Other classes of signals, including N-acyl-L-homoserine lactones, which are used by bacteria for cell-to-cell communication, can be perceived by plants to modulate gene expression, metabolism and growth. Finally, we discuss the role played by volatile organic compounds released by certain plant growth-promoting rhizobacteria in plant immunity and developmental processes. The picture that emerges is one in which plants and microbes communicate themselves through transkingdom signaling systems involving classic and novel signals. PMID:19820333

  9. Manufactured soils for plant growth at a lunar base

    NASA Technical Reports Server (NTRS)

    Ming, Douglas W.

    1989-01-01

    Advantages and disadvantages of synthetic soils are discussed. It is pointed out that synthetic soils may provide the proper physical and chemical properties necessary to maximize plant growth, such as a toxic-free composition and cation exchange capacities. The importance of nutrient retention, aeration, moisture retention, and mechanical support as qualities for synthetic soils are stressed. Zeoponics, or the cultivation of plants in zeolite substrates that both contain essential plant-growth cations on their exchange sites and have minor amounts of mineral phases and/or anion-exchange resins that supply essential plant growth ions, is discussed. It is suggested that synthetic zeolites at lunar bases could provide adsorption media for separation of various gases, act as catalysts and as molecular sieves, and serve as cation exchangers in sewage-effluent treatment, radioactive-waste disposal, and pollution control. A flow chart of a potential zeoponics system illustrates this process.

  10. Inhibition of nitrification in municipal wastewater-treating photobioreactors: Effect on algal growth and nutrient uptake.

    PubMed

    Krustok, I; Odlare, M; Truu, J; Nehrenheim, E

    2016-02-01

    The effect of inhibiting nitrification on algal growth and nutrient uptake was studied in photobioreactors treating municipal wastewater. As previous studies have indicated that algae prefer certain nitrogen species to others, and because nitrifying bacteria are inhibited by microalgae, it is important to shed more light on these interactions. In this study allylthiourea (ATU) was used to inhibit nitrification in wastewater-treating photobioreactors. The nitrification-inhibited reactors were compared to control reactors with no ATU added. Microalgae had higher growth in the inhibited reactors, resulting in a higher chlorophyll a concentration. The species mix also differed, with Chlorella and Scenedesmus being the dominant genera in the control reactors and Cryptomonas and Chlorella dominating in the inhibited reactors. The nitrogen speciation in the reactors after 8 days incubation was also different in the two setups, with N existing mostly as NH4-N in the inhibited reactors and as NO3-N in the control reactors. PMID:26716890

  11. Microsensor Technologies for Plant Growth System Monitoring

    NASA Technical Reports Server (NTRS)

    Kim, Chang-Soo

    2004-01-01

    This document covered the following: a) demonstration of feasibility of microsensor for tube and particulate growth systems; b) Dissolved oxygen; c)Wetness; d) Flexible microfluidic substrate with microfluidic channels and microsensor arrays; e)Dynamic root zone control/monitoring in microgravity; f)Rapid prototyping of phytoremediation; and g) A new tool for root physiology and pathology.

  12. Plant growth promotion induced by phosphate solubilizing endophytic Pseudomonas isolates.

    PubMed

    Oteino, Nicholas; Lally, Richard D; Kiwanuka, Samuel; Lloyd, Andrew; Ryan, David; Germaine, Kieran J; Dowling, David N

    2015-01-01

    The use of plant growth promoting bacterial inoculants as live microbial biofertilizers provides a promising alternative to chemical fertilizers and pesticides. Inorganic phosphate solubilization is one of the major mechanisms of plant growth promotion by plant associated bacteria. This involves bacteria releasing organic acids into the soil which solubilize the phosphate complexes converting them into ortho-phosphate which is available for plant up-take and utilization. The study presented here describes the ability of endophytic bacteria to produce gluconic acid (GA), solubilize insoluble phosphate, and stimulate the growth of Pisum sativum L. plants. This study also describes the genetic systems within three of these endophyte strains thought to be responsible for their effective phosphate solubilizing abilities. The results showed that many of the endophytic strains produced GA (14-169 mM) and have moderate to high phosphate solubilization capacities (~400-1300 mg L(-1)). When inoculated into P. sativum L. plants grown in soil under soluble phosphate limiting conditions, the endophytes that produced medium-high levels of GA displayed beneficial plant growth promotion effects. PMID:26257721

  13. Plant growth promotion induced by phosphate solubilizing endophytic Pseudomonas isolates

    PubMed Central

    Oteino, Nicholas; Lally, Richard D.; Kiwanuka, Samuel; Lloyd, Andrew; Ryan, David; Germaine, Kieran J.; Dowling, David N.

    2015-01-01

    The use of plant growth promoting bacterial inoculants as live microbial biofertilizers provides a promising alternative to chemical fertilizers and pesticides. Inorganic phosphate solubilization is one of the major mechanisms of plant growth promotion by plant associated bacteria. This involves bacteria releasing organic acids into the soil which solubilize the phosphate complexes converting them into ortho-phosphate which is available for plant up-take and utilization. The study presented here describes the ability of endophytic bacteria to produce gluconic acid (GA), solubilize insoluble phosphate, and stimulate the growth of Pisum sativum L. plants. This study also describes the genetic systems within three of these endophyte strains thought to be responsible for their effective phosphate solubilizing abilities. The results showed that many of the endophytic strains produced GA (14–169 mM) and have moderate to high phosphate solubilization capacities (~400–1300 mg L−1). When inoculated into P. sativum L. plants grown in soil under soluble phosphate limiting conditions, the endophytes that produced medium-high levels of GA displayed beneficial plant growth promotion effects. PMID:26257721

  14. Inhibition of influenza virus replication by plant-derived isoquercetin.

    PubMed

    Kim, Yunjeong; Narayanan, Sanjeev; Chang, Kyeong-Ok

    2010-11-01

    Influenza virus infects the respiratory system of human and animals causing mild to severe illness which could lead to death. Although vaccines are available, there is still a great need for influenza antiviral drugs to reduce disease progression and virus transmission. Currently two classes (M2 channel blockers and neuraminidase inhibitors) of FDA-approved influenza antiviral drugs are available, but there are great concerns of emergence of viral resistance. Therefore, timely development of new antiviral drugs against influenza viruses is crucial. Plant-derived polyphenols have been studied for antioxidant activity, anti-carcinogenic, and cardio- and neuroprotective actions. Recently, some polyphenols, such as resveratrol and epigallocatechin gallate, showed significant anti-influenza activity in vitro and/or in vivo. Therefore we investigated selected polyphenols for their antiviral activity against influenza A and B viruses. Among the polyphenols we tested, isoquercetin inhibited the replication of both influenza A and B viruses at the lowest effective concentration. In a double treatment of isoquercetin and amantadine, synergistic effects were observed on the reduction of viral replication in vitro. The serial passages of virus in the presence of isoquercetin did not lead to the emergence of resistant virus, and the addition of isoquercetin to amantadine or oseltamivir treatment suppressed the emergence of amantadine- or oseltamivir-resistant virus. In a mouse model of influenza virus infection, isoquercetin administered intraperitoneally to mice inoculated with human influenza A virus significantly decreased the virus titers and pathological changes in the lung. Our results suggest that isoquercetin may have the potential to be developed as a therapeutic agent for the treatment of influenza virus infection and for the suppression of resistance in combination therapy with existing drugs.

  15. Inhibition of growth and alteration of host cell interactions of Pasteurella multocida with natural byproducts.

    PubMed

    Salaheen, S; Almario, J A; Biswas, D

    2014-06-01

    Pasteurella multocida is a leading cause of fowl cholera in both free-range pasture and conventional/commercially raised poultry. Its infection is a serious threat to poultry health and overall flock viability. Organic poultry is comparatively more vulnerable to this pathogen. It is a significant cause of production loss and price increase of poultry products, specifically organic poultry products. Some plant products are well documented as sources of natural antimicrobials such as polyphenols found in different berry pomaces and citrus oil. Pomace, a byproduct (primarily of seeds and skins) of fruits used for juice and wine production, and citrus oil, the byproduct of citrus juice production, show promising antimicrobial activity against various pathogens. Here, we showed for the first time that blackberry and blueberry pomace extracts and citrus oil inhibited P. multocida growth. Minimum bactericidal concentrations were determined as 0.3 and 0.4 mg/mL gallic acid equivalent for blackberry and blueberry pomace extracts, respectively. Similarly, only 0.05% citrus oil (vol/vol) completely inhibited P. multocida growth. Under shaking conditions, the antimicrobial activity of both pomace extracts and citrus oil was more intensive. Even citrus oil vapor also significantly reduced the growth of P. multocida. In addition, cell surface hydrophobicity of P. multocida was increased by 2- to 3-fold and its adherence to chicken fibroblast (DF1) and bovine mammary gland (MacT) cells was reduced significantly in the presence of pomace extracts only. This study indicates that these natural products might be good alternatives to conventional antimicrobial agents, and hence, may be used as feed or water supplements to control fowl cholera and reduce production loss caused by P. multocida. PMID:24879687

  16. Selected dietary (poly)phenols inhibit periodontal pathogen growth and biofilm formation.

    PubMed

    Shahzad, Muhammad; Millhouse, Emma; Culshaw, Shauna; Edwards, Christine A; Ramage, Gordon; Combet, Emilie

    2015-03-01

    Periodontitis (PD) is a chronic infectious disease mediated by bacteria in the oral cavity. (Poly)phenols (PPs), ubiquitous in plant foods, possess antimicrobial activities and may be useful in the prevention and management of periodontitis. The objective of this study was to test the antibacterial effects of selected PPs on periodontal pathogens, on both planktonic and biofilm modes of growth. Selected PPs (n = 48) were screened against Streptococcus mitis (S. mitis), Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans), Fusobacterium nucleatum (F. nucleatum) and Porphyromonas gingivalis (P. gingivalis). The antibacterial potential of each compound was evaluated in terms of planktonic minimum inhibitory concentration (PMIC) and planktonic minimum bactericidal concentration (PMBC) using standardized broth microdilution assays. The most active PPs were further tested for their effect on mono-species and multi-species biofilms using a colorimetric resazurin-based viability assay and scanning electron microscopy. Of the 48 PPs tested, 43 showed effective inhibition of planktonic growth of one or more test strains, of which curcumin was the most potent (PMIC range = 7.8-62.5 μg mL(-1)), followed by pyrogallol (PMIC range = 2.4-2500 μg mL(-1)), pyrocatechol (MIC range = 4.9-312.5 μg mL(-1)) and quercetin (PMIC range = 31.2-500 μg mL(-1)). At this concentration, adhesion of curcumin and quercetin to the substrate also inhibited adhesion of S. mitis, and biofilm formation and maturation. While both curcumin and quercetin were able to alter architecture of mature multi-species biofilms, only curcumin-treated biofilms displayed a significantly reduced metabolic activity. Overall, PPs possess antibacterial activities against periodontopathic bacteria in both planktonic and biofilm modes of growth. Further cellular and in vivo studies are necessary to confirm their beneficial activities and potential use in the prevention and or treatment of periodontal

  17. Selected dietary (poly)phenols inhibit periodontal pathogen growth and biofilm formation.

    PubMed

    Shahzad, Muhammad; Millhouse, Emma; Culshaw, Shauna; Edwards, Christine A; Ramage, Gordon; Combet, Emilie

    2015-03-01

    Periodontitis (PD) is a chronic infectious disease mediated by bacteria in the oral cavity. (Poly)phenols (PPs), ubiquitous in plant foods, possess antimicrobial activities and may be useful in the prevention and management of periodontitis. The objective of this study was to test the antibacterial effects of selected PPs on periodontal pathogens, on both planktonic and biofilm modes of growth. Selected PPs (n = 48) were screened against Streptococcus mitis (S. mitis), Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans), Fusobacterium nucleatum (F. nucleatum) and Porphyromonas gingivalis (P. gingivalis). The antibacterial potential of each compound was evaluated in terms of planktonic minimum inhibitory concentration (PMIC) and planktonic minimum bactericidal concentration (PMBC) using standardized broth microdilution assays. The most active PPs were further tested for their effect on mono-species and multi-species biofilms using a colorimetric resazurin-based viability assay and scanning electron microscopy. Of the 48 PPs tested, 43 showed effective inhibition of planktonic growth of one or more test strains, of which curcumin was the most potent (PMIC range = 7.8-62.5 μg mL(-1)), followed by pyrogallol (PMIC range = 2.4-2500 μg mL(-1)), pyrocatechol (MIC range = 4.9-312.5 μg mL(-1)) and quercetin (PMIC range = 31.2-500 μg mL(-1)). At this concentration, adhesion of curcumin and quercetin to the substrate also inhibited adhesion of S. mitis, and biofilm formation and maturation. While both curcumin and quercetin were able to alter architecture of mature multi-species biofilms, only curcumin-treated biofilms displayed a significantly reduced metabolic activity. Overall, PPs possess antibacterial activities against periodontopathic bacteria in both planktonic and biofilm modes of growth. Further cellular and in vivo studies are necessary to confirm their beneficial activities and potential use in the prevention and or treatment of periodontal

  18. Harzianolide, a novel plant growth regulator and systemic resistance elicitor from Trichoderma harzianum.

    PubMed

    Cai, Feng; Yu, Guanghui; Wang, Ping; Wei, Zhong; Fu, Lin; Shen, Qirong; Chen, Wei

    2013-12-01

    A detailed understanding of the effect of natural products on plant growth and protection will underpin new product development for plant production. The isolation and characterization of a known secondary metabolite named harzianolide from Trichoderma harzianum strain SQR-T037 were described, and the bioactivity of the purified compound as well as the crude metabolite extract in plant growth promotion and systemic resistance induction was investigated in this study. The results showed that harzianolide significantly promoted tomato seedling growth by up to 2.5-fold (dry weight) at a concentration of 0.1 ppm compared with the control. The result of root scan suggested that Trichoderma secondary metabolites may influence the early stages of plant growth through better root development for the enhancement of root length and tips. Both of the purified harzianolide and crude metabolite extract increased the activity of some defense-related enzymes to response to oxidative stress. Examination of six defense-related gene expression by real-time reverse transcription-PCR analysis revealed that harzianolide induces the expression of genes involved in the salicylic acid (PR1 and GLU) and jasmonate/ethylene (JERF3) signaling pathways while crude metabolite extract inhibited some gene expression (CHI-II and PGIP) related to basal defense in tomato plants. Further experiment showed that a subsequent challenge of harzianolide-pretreated plants with the pathogen Sclerotinia sclerotiorum resulted in higher systemic resistance by the reduction of lesion size. These results indicate that secondary metabolites of Trichoderma spp., like harzianolide, may play a novel role in both plant growth regulation and plant defense responses.

  19. Harzianolide, a novel plant growth regulator and systemic resistance elicitor from Trichoderma harzianum.

    PubMed

    Cai, Feng; Yu, Guanghui; Wang, Ping; Wei, Zhong; Fu, Lin; Shen, Qirong; Chen, Wei

    2013-12-01

    A detailed understanding of the effect of natural products on plant growth and protection will underpin new product development for plant production. The isolation and characterization of a known secondary metabolite named harzianolide from Trichoderma harzianum strain SQR-T037 were described, and the bioactivity of the purified compound as well as the crude metabolite extract in plant growth promotion and systemic resistance induction was investigated in this study. The results showed that harzianolide significantly promoted tomato seedling growth by up to 2.5-fold (dry weight) at a concentration of 0.1 ppm compared with the control. The result of root scan suggested that Trichoderma secondary metabolites may influence the early stages of plant growth through better root development for the enhancement of root length and tips. Both of the purified harzianolide and crude metabolite extract increased the activity of some defense-related enzymes to response to oxidative stress. Examination of six defense-related gene expression by real-time reverse transcription-PCR analysis revealed that harzianolide induces the expression of genes involved in the salicylic acid (PR1 and GLU) and jasmonate/ethylene (JERF3) signaling pathways while crude metabolite extract inhibited some gene expression (CHI-II and PGIP) related to basal defense in tomato plants. Further experiment showed that a subsequent challenge of harzianolide-pretreated plants with the pathogen Sclerotinia sclerotiorum resulted in higher systemic resistance by the reduction of lesion size. These results indicate that secondary metabolites of Trichoderma spp., like harzianolide, may play a novel role in both plant growth regulation and plant defense responses. PMID:24080397

  20. Growth but not photosynthesis response of a host plant to infection by a holoparasitic plant depends on nitrogen supply.

    PubMed

    Shen, Hao; Xu, Shu-Jun; Hong, Lan; Wang, Zhang-Ming; Ye, Wan-Hui

    2013-01-01

    Parasitic plants can adversely influence the growth of their hosts by removing resources and by affecting photosynthesis. Such negative effects depend on resource availability. However, at varied resource levels, to what extent the negative effects on growth are attributed to the effects on photosynthesis has not been well elucidated. Here, we examined the influence of nitrogen supply on the growth and photosynthesis responses of the host plant Mikania micrantha to infection by the holoparasite Cuscuta campestris by focusing on the interaction of nitrogen and infection. Mikania micrantha plants fertilized at 0.2, 1 and 5 mM nitrate were grown with and without C. campestris infection. We observed that the infection significantly reduced M. micrantha growth at each nitrate fertilization and more severely at low than at high nitrate. Such alleviation at high nitrate was largely attributed to a stronger influence of infection on root biomass at low than at high nitrate fertilization. However, although C. campestris altered allometry and inhibited host photosynthesis, the magnitude of the effects was independent of nitrate fertilizations. The infection reduced light saturation point, net photosynthesis at saturating irradiances, apparent quantum yield, CO2 saturated rate of photosynthesis, carboxylation efficiency, the maximum carboxylation rate of Rubisco, and maximum light-saturated rate of electron transport, and increased light compensation point in host leaves similarly across nitrate levels, corresponding to a similar magnitude of negative effects of the parasite on host leaf soluble protein and Rubisco concentrations, photosynthetic nitrogen use efficiency and stomatal conductance across nitrate concentrations. Thus, the more severe inhibition in host growth at low than at high nitrate supplies cannot be attributed to a greater parasite-induced reduction in host photosynthesis, but the result of a higher proportion of host resources transferred to the parasite at

  1. Growth promotion and yield enhancement of peanut (Arachis hypogaea L.) by application of plant growth-promoting rhizobacteria.

    PubMed

    Dey, R; Pal, K K; Bhatt, D M; Chauhan, S M

    2004-01-01

    Although plant growth-promoting rhizobacteria (PGPR) have been reported to influence plant growth, yield and nutrient uptake by an array of mechanisms, the specific traits by which PGPR promote plant growth, yield and nutrient uptake were limited to the expression of one or more of the traits expressed at a given environment of plant-microbe interaction. We selected nine different isolates of PGPR from a pool of 233 rhizobacterial isolates obtained from the peanut rhizosphere on the basis of ACC-deaminase activity. The nine isolates were selected, initially, on the basis of germinating seed bioassay in which the root length of the seedling was enhanced significantly over the untreated control. All the nine isolates were identified as Pseudomonas spp. Four of these isolates, viz. PGPR1, PGPR2, PGPR4 and PGPR7 (all fluorescent pseudomonads), were the best in producing siderophore and indole acetic acid (IAA). In addition to IAA and siderophore-producing attributes, Pseudomonas fluorescens PGPR1 also possessed the characters like tri-calcium phosphate solubilization, ammonification and inhibited Aspergillus niger and A. flavus in vitro. P. fluorescens PGPR2 differed from PGPR1 in the sense that it did not show ammonification. In addition to the traits exhibited by PGPR1, PGPR4 showed strong in vitro inhibition to Sclerotium rolfsii. The performances of these selected plant growth-promoting rhizobacterial isolates were repeatedly evaluated for 3 years in pot and field trials. Seed inoculation of these three isolates, viz. PGPR1, PGPR2 and PGPR4, resulted in a significantly higher pod yield than the control, in pots, during rainy and post-rainy seasons. The contents of nitrogen and phosphorus in soil, shoot and kernel were also enhanced significantly in treatments inoculated with these rhizobacterial isolates in pots during both the seasons. In the field trials, however, there was wide variation in the performance of the PGPR isolates in enhancing the growth and yield

  2. Galactose inhibits auxin-induced growth of Avena coleoptiles by two mechanisms

    NASA Technical Reports Server (NTRS)

    Cheung, S. P.; Cleland, R. E.

    1991-01-01

    Galactose inhibits auxin-induced growth of Avena coleoptiles by at least two mechanisms. First, it inhibits auxin-induced H(+)-excretion needed for the initiation of rapid elongation. Galactose cannot be doing so by directly interfering with the ATPase since fusicoccin-induced H(+)-excretion is not affected. Secondly, galactose inhibits long-term auxin-induced growth, even in an acidic (pH 4.5) solution. This may be due to an inhibition of cell wall synthesis. However, galactose does not reduce the capacity of walls to be loosened by H+, given exogenously or excreted in response to fusicoccin.

  3. Inhibition of growth and mycotoxin production of Aspergillus flavus and Aspergillus parasiticus by extracts of Agave species.

    PubMed

    Sánchez, Eduardo; Heredia, Norma; García, Santos

    2005-02-15

    In this work, the effect of ethanolic, methanolic and aqueous extracts of Agave asperrima and Agave striata on growth and production of aflatoxin (in A&M medium) and cyclopiazonic acid (CPA; in Czpaek-Dox medium) and on growth in corn under storage conditions was determined. Aspergillus strains were inoculated (10(6) conidia per ml of medium or per 6 g of corn), then plant extracts were added and incubated without shaking at 28 degrees C for 8 days (for aflatoxin-producing analysis) or for 12 days (for CPA-producing analysis). Aflatoxin was assayed by HPLC and cyclopiazonic acid by absorbance at 580 nm using the Erlich reagent. The extracts that most effectively inhibited growth were those from the flowers of both plants. These exhibited an MIC from 0.5 to 2 mg/ml in culture media. Extracts from scape showed an MIC from 15 to 30 mg/ml in culture media. The MIC of the flower extracts was higher (>30 mg/g) when examined in corn. However, concentrations lower than the MIC drastically inhibited production of aflatoxins in culture medium or in corn. Half of the MIC inhibited 99% of the production of aflatoxins and 85% of cyclopiazonic acid.

  4. The transcriptional regulator BZR1 mediates trade-off between plant innate immunity and growth

    PubMed Central

    Lozano-Durán, Rosa; Macho, Alberto P; Boutrot, Freddy; Segonzac, Cécile; Somssich, Imre E; Zipfel, Cyril

    2013-01-01

    The molecular mechanisms underlying the trade-off between plant innate immunity and steroid-mediated growth are controversial. Here, we report that activation of the transcription factor BZR1 is required and sufficient for suppression of immune signaling by brassinosteroids (BR). BZR1 induces the expression of several WRKY transcription factors that negatively control early immune responses. In addition, BZR1 associates with WRKY40 to mediate the antagonism between BR and immune signaling. We reveal that BZR1-mediated inhibition of immunity is particularly relevant when plant fast growth is required, such as during etiolation. Thus, BZR1 acts as an important regulator mediating the trade-off between growth and immunity upon integration of environmental cues. DOI: http://dx.doi.org/10.7554/eLife.00983.001 PMID:24381244

  5. Release characteristics of encapsulated formulations incorporating plant growth factors.

    PubMed

    Wybraniec, Slawomir; Schwartz, Liliana; Wiesman, Zeev; Markus, Arie; Wolf, David

    2002-05-01

    The release characteristics of encapsulated formulations containing a combination of plant growth factors (PGF)--plant hormones (IBA, paclobutrazol), nutrients (fertilizers, microelements), and fungicide (prochloraz)--were studied. The formulations were prepared by encapsulating the active ingredients in a polyethylene matrix and, in some cases, subsequently coating the product with polyurethane. Dissolution experiments were carried out with both coated and non-coated formulations to determine the sustained release patterns of the active ingredients. The PGF controlled-release systems obtained have been shown to promote development of root systems, vegetative growth, and reproductive development in cuttings, potted plants, or garden plants of various plant species. These beneficial effects are attributable to the lasting and balanced PGF availability provided by these systems. PMID:12009194

  6. Release characteristics of encapsulated formulations incorporating plant growth factors.

    PubMed

    Wybraniec, Slawomir; Schwartz, Liliana; Wiesman, Zeev; Markus, Arie; Wolf, David

    2002-05-01

    The release characteristics of encapsulated formulations containing a combination of plant growth factors (PGF)--plant hormones (IBA, paclobutrazol), nutrients (fertilizers, microelements), and fungicide (prochloraz)--were studied. The formulations were prepared by encapsulating the active ingredients in a polyethylene matrix and, in some cases, subsequently coating the product with polyurethane. Dissolution experiments were carried out with both coated and non-coated formulations to determine the sustained release patterns of the active ingredients. The PGF controlled-release systems obtained have been shown to promote development of root systems, vegetative growth, and reproductive development in cuttings, potted plants, or garden plants of various plant species. These beneficial effects are attributable to the lasting and balanced PGF availability provided by these systems.

  7. Analysing growth and development of plants jointly using developmental growth stages

    PubMed Central

    Dambreville, Anaëlle; Lauri, Pierre-Éric; Normand, Frédéric; Guédon, Yann

    2015-01-01

    Background and Aims Plant growth, the increase of organ dimensions over time, and development, the change in plant structure, are often studied as two separate processes. However, there is structural and functional evidence that these two processes are strongly related. The aim of this study was to investigate the co-ordination between growth and development using mango trees, which have well-defined developmental stages. Methods Developmental stages, determined in an expert way, and organ sizes, determined from objective measurements, were collected during the vegetative growth and flowering phases of two cultivars of mango, Mangifera indica. For a given cultivar and growth unit type (either vegetative or flowering), a multistage model based on absolute growth rate sequences deduced from the measurements was first built, and then growth stages deduced from the model were compared with developmental stages. Key Results Strong matches were obtained between growth stages and developmental stages, leading to a consistent definition of integrative developmental growth stages. The growth stages highlighted growth asynchronisms between two topologically connected organs, namely the vegetative axis and its leaves. Conclusions Integrative developmental growth stages emphasize that developmental stages are closely related to organ growth rates. The results are discussed in terms of the possible physiological processes underlying these stages, including plant hydraulics, biomechanics and carbohydrate partitioning. PMID:25452250

  8. Polymer film deposition on agar using a dielectric barrier discharge jet and its bacterial growth inhibition

    NASA Astrophysics Data System (ADS)

    Tsai, T.-C.; Cho, J.; Mcintyre, K.; Jo, Y.-K.; Staack, D.

    2012-08-01

    Polymer film deposition on agar in ambient air was achieved using the helium dielectric barrier discharge jet (DBD jet) fed with polymer precursors, and the bacterial growth inhibition due to the deposited film was observed. The DBD jet with precursor addition was more efficient at sterilization than a helium-only DBD jet. On the areas where polymer films cover the agar the bacterial growth was significantly inhibited. The inhibition efficacy showed dependence on the film thickness. The DBD jet without precursor also created a modified agar layer, which may slow the growth of some bacterial strains.

  9. Jack bean urease inhibition by crude juices of Allium and Brassica plants. Determination of thiosulfinates.

    PubMed

    Olech, Zofia; Zaborska, Wiesława; Kot, Mirosława

    2014-02-15

    The aim of this study was the elucidation of the inhibitory influence of Allium (garlic, onion, leek) and Brassica (cabbage, Brussels sprouts) plants juices, on jack bean urease activity. Concentrations of thiosulfinates, the compounds responsible for the inhibition, were determined in studied materials. The kinetics and mechanism of the inhibitions were investigated. Biphasic, time-dependent courses of the inhibition reactions were observed for all tested Allium and Brussels sprouts from Brassica. The cabbage material caused the monophasic course of the inhibition. In the presence of dithiothreitol, a total reactivation of the inhibited urease proceeded for the tested plants except for the onion. The onion juice modified urease, regained only half of the initial activity. The irreversible contribution was related to the presence of 1-propanethial-S-oxide, cepaenes and zwiebelanes formed in the onion juice. It was found that the thermal processing of the plant juices, results in the decrease of thiosulfinates concentration, as well as the efficiency of urease inhibition.

  10. Genetic and phenotypic diversity of plant growth promoting rhizobacteria isolated from sugarcane plants growing in pakistan.

    PubMed

    Mehnaz, Samina; Baig, Deeba Noreen; Lazarovits, George

    2010-12-01

    Bacteria were isolated from roots of sugarcane varieties grown in the fields of Punjab. They were identified by using API20E/NE bacterial identification kits and from sequences of 16S rRNA and amplicons of the cpn60 gene. The majority of bacteria were found to belong to the genera of Enterobacter, Pseudomonas, and Klebsiella, but members of genera Azospirillum, Rhizobium, Rahnella, Delftia, Caulobacter, Pannonibacter, Xanthomonas, and Stenotrophomonas were also found. The community, however, was dominated by members of the Pseudomonadaceae and Enterobacteriaceae, as representatives of these genera were found in samples from every variety and location examined. All isolates were tested for the presence of five enzymes and seven factors known to be associated with plant growth promotion. Ten isolates showed lipase activity and eight were positive for protease activity. Cellulase, chitinase, and pectinase were not detected in any strain. Nine strains showed nitrogen fixing ability (acetylene reduction assay) and 26 were capable of solubilizing phosphate. In the presence of 100 mg/l tryptophan, all strains except one produced indole acetic acid in the growth medium. All isolates were positive for ACC deaminase activity. Six strains produced homoserine lactones and three produced HCN and hexamate type siderophores. One isolate was capable of inhibiting the growth of 24 pathogenic fungal strains of Colletotrichum, Fusarium, Pythium, and Rhizoctonia spp. In tests of their abilities to grow under a range of temperature, pH, and NaCl concentrations, all isolates grew well on plates with 3% NaCl and most of them grew well at 4 to 41degrees C and at pH 11.

  11. Helical growth in plant organs: mechanisms and significance.

    PubMed

    Smyth, David R

    2016-09-15

    Many plants show some form of helical growth, such as the circular searching movements of growing stems and other organs (circumnutation), tendril coiling, leaf and bud reversal (resupination), petal arrangement (contortion) and leaf blade twisting. Recent genetic findings have revealed that such helical growth may be associated with helical arrays of cortical microtubules and of overlying cellulose microfibrils. An alternative mechanism of coiling that is based on differential contraction within a bilayer has also recently been identified and underlies at least some of these growth patterns. Here, I provide an overview of the genes and cellular processes that underlie helical patterning. I also discuss the diversity of helical growth patterns in plants, highlighting their potential adaptive significance and comparing them with helical growth patterns in animals. PMID:27624832

  12. Relationship between Hexokinase and the Aquaporin PIP1 in the Regulation of Photosynthesis and Plant Growth

    PubMed Central

    Kelly, Gilor; Sade, Nir; Attia, Ziv; Secchi, Francesca; Zwieniecki, Maciej; Holbrook, N. Michele; Levi, Asher; Alchanatis, Victor; Moshelion, Menachem; Granot, David

    2014-01-01

    Increased expression of the aquaporin NtAQP1, which is known to function as a plasmalemma channel for CO2 and water, increases the rate of both photosynthesis and transpiration. In contrast, increased expression of Arabidopsis hexokinase1 (AtHXK1), a dual-function enzyme that mediates sugar sensing, decreases the expression of photosynthetic genes and the rate of transpiration and inhibits growth. Here, we show that AtHXK1 also decreases root and stem hydraulic conductivity and leaf mesophyll CO2 conductance (gm). Due to their opposite effects on plant development and physiology, we examined the relationship between NtAQP1 and AtHXK1 at the whole-plant level using transgenic tomato plants expressing both genes simultaneously. NtAQP1 significantly improved growth and increased the transpiration rates of AtHXK1-expressing plants. Reciprocal grafting experiments indicated that this complementation occurs when both genes are expressed simultaneously in the shoot. Yet, NtAQP1 had only a marginal effect on the hydraulic conductivity of the double-transgenic plants, suggesting that the complementary effect of NtAQP1 is unrelated to shoot water transport. Rather, NtAQP1 significantly increased leaf mesophyll CO2 conductance and enhanced the rate of photosynthesis, suggesting that NtAQP1 facilitated the growth of the double-transgenic plants by enhancing mesophyll conductance of CO2. PMID:24498392

  13. Relationship between hexokinase and the aquaporin PIP1 in the regulation of photosynthesis and plant growth.

    PubMed

    Kelly, Gilor; Sade, Nir; Attia, Ziv; Secchi, Francesca; Zwieniecki, Maciej; Holbrook, N Michele; Levi, Asher; Alchanatis, Victor; Moshelion, Menachem; Granot, David

    2014-01-01

    Increased expression of the aquaporin NtAQP1, which is known to function as a plasmalemma channel for CO₂ and water, increases the rate of both photosynthesis and transpiration. In contrast, increased expression of Arabidopsis hexokinase1 (AtHXK1), a dual-function enzyme that mediates sugar sensing, decreases the expression of photosynthetic genes and the rate of transpiration and inhibits growth. Here, we show that AtHXK1 also decreases root and stem hydraulic conductivity and leaf mesophyll CO₂ conductance (g(m)). Due to their opposite effects on plant development and physiology, we examined the relationship between NtAQP1 and AtHXK1 at the whole-plant level using transgenic tomato plants expressing both genes simultaneously. NtAQP1 significantly improved growth and increased the transpiration rates of AtHXK1-expressing plants. Reciprocal grafting experiments indicated that this complementation occurs when both genes are expressed simultaneously in the shoot. Yet, NtAQP1 had only a marginal effect on the hydraulic conductivity of the double-transgenic plants, suggesting that the complementary effect of NtAQP1 is unrelated to shoot water transport. Rather, NtAQP1 significantly increased leaf mesophyll CO₂ conductance and enhanced the rate of photosynthesis, suggesting that NtAQP1 facilitated the growth of the double-transgenic plants by enhancing mesophyll conductance of CO₂.

  14. Age matters: the effects of volatile organic compounds emitted by Trichoderma atroviride on plant growth.

    PubMed

    Lee, Samantha; Hung, Richard; Yap, Melanie; Bennett, Joan W

    2015-06-01

    Studying the effects of microbial volatile organic compounds (VOCs) on plant growth is challenging because the production of volatiles depends on many environmental factors. Adding to this complexity, the method of volatile exposure itself can lead to different responses in plants and may account for some of the contrasting results. In this work, we present an improved experimental design, a plate-within-a-plate method, to study the effects of VOCs produced by filamentous fungi. We demonstrate that the plant growth response to VOCs is dependent on the age of the plant and fungal cultures. Plants exposed to volatiles emitted by 5-day-old Trichoderma atroviride for 14 days exhibited inhibition, while plants exposed to other exposure conditions had growth promotion or no significant change. Using GC-MS, we compared fungal volatile emission of 5-day-old and 14-day-old T. atroviride. As the fungi aged, a few compounds were no longer detected, but 24 new compounds were discovered.

  15. Bismuth(III) deferiprone effectively inhibits growth of Desulfovibrio desulfuricans ATCC 27774.

    PubMed

    Barton, Larry L; Lyle, Daniel A; Ritz, Nathaniel L; Granat, Alex S; Khurshid, Ali N; Kherbik, Nada; Hider, Robert; Lin, Henry C

    2016-04-01

    Sulfate-reducing bacteria have been implicated in inflammatory bowel diseases and ulcerative colitis in humans and there is an interest in inhibiting the growth of these sulfide-producing bacteria. This research explores the use of several chelators of bismuth to determine the most effective chelator to inhibit the growth of sulfate-reducing bacteria. For our studies, Desulfovibrio desulfuricans ATCC 27774 was grown with nitrate as the electron acceptor and chelated bismuth compounds were added to test for inhibition of growth. Varying levels of inhibition were attributed to bismuth chelated with subsalicylate or citrate but the most effective inhibition of growth by D. desulfuricans was with bismuth chelated by deferiprone, 3-hydroxy-1,2-dimethyl-4(1H)-pyridone. Growth of D. desulfuricans was inhibited by 10 μM bismuth as deferiprone:bismuth with either nitrate or sulfate respiration. Our studies indicate deferiprone:bismuth has bacteriostatic activity on D. desulfuricans because the inhibition can be reversed following exposure to 1 mM bismuth for 1 h at 32 °C. We suggest that deferiprone is an appropriate chelator for bismuth to control growth of sulfate-reducing bacteria because deferiprone is relatively nontoxic to animals, including humans, and has been used for many years to bind Fe(III) in the treatment of β-thalassemia. PMID:26896170

  16. Making healthier or killing enemies? Bacterial volatile-elicited plant immunity plays major role upon protection of Arabidopsis than the direct pathogen inhibition

    PubMed Central

    Sharifi, Rouhallah; Ryu, Choong-Min

    2016-01-01

    ABSTRACT Bacterial volatiles protect plants either by directly inhibiting a pathogenic fungus or by improving the defense capabilities of plants. The effect of bacterial volatiles on fungal growth was dose-dependent. A low dosage did not have a noticeable effect on Botrytis cinerea growth and development, but was sufficient to elicit induced resistance in Arabidopsis thaliana. Bacterial volatiles displayed negative effects on biofilm formation on a polystyrene surface and in in planta leaf colonization of B. cinerea. However, bacterial volatile-mediated induced resistance was the major mechanism mediating protection of plants from B. cinerea. It was responsible for more than 90% of plant protection in comparison with direct fungal inhibition. Our results broaden our knowledge of the role of bacterial volatiles in plant protection. PMID:27574539

  17. Making healthier or killing enemies? Bacterial volatile-elicited plant immunity plays major role upon protection of Arabidopsis than the direct pathogen inhibition.

    PubMed

    Sharifi, Rouhallah; Ryu, Choong-Min

    2016-01-01

    Bacterial volatiles protect plants either by directly inhibiting a pathogenic fungus or by improving the defense capabilities of plants. The effect of bacterial volatiles on fungal growth was dose-dependent. A low dosage did not have a noticeable effect on Botrytis cinerea growth and development, but was sufficient to elicit induced resistance in Arabidopsis thaliana. Bacterial volatiles displayed negative effects on biofilm formation on a polystyrene surface and in in planta leaf colonization of B. cinerea. However, bacterial volatile-mediated induced resistance was the major mechanism mediating protection of plants from B. cinerea. It was responsible for more than 90% of plant protection in comparison with direct fungal inhibition. Our results broaden our knowledge of the role of bacterial volatiles in plant protection. PMID:27574539

  18. Making healthier or killing enemies? Bacterial volatile-elicited plant immunity plays major role upon protection of Arabidopsis than the direct pathogen inhibition.

    PubMed

    Sharifi, Rouhallah; Ryu, Choong-Min

    2016-01-01

    Bacterial volatiles protect plants either by directly inhibiting a pathogenic fungus or by improving the defense capabilities of plants. The effect of bacterial volatiles on fungal growth was dose-dependent. A low dosage did not have a noticeable effect on Botrytis cinerea growth and development, but was sufficient to elicit induced resistance in Arabidopsis thaliana. Bacterial volatiles displayed negative effects on biofilm formation on a polystyrene surface and in in planta leaf colonization of B. cinerea. However, bacterial volatile-mediated induced resistance was the major mechanism mediating protection of plants from B. cinerea. It was responsible for more than 90% of plant protection in comparison with direct fungal inhibition. Our results broaden our knowledge of the role of bacterial volatiles in plant protection.

  19. A chemical pollen suppressant inhibits auxin-induced growth in maize coleoptile sections

    SciTech Connect

    Vesper, M.J. ); Cross, J.W. )

    1990-05-01

    Chemical inhibitors of pollen development having a phenylcinnoline carboxylate structure were found to inhibit IAA- and 1-NAA-induced growth in maize coleoptile sections. The inhibitor (100 {mu}M) used in these experiments caused approx. 35% reduction in auxin-induced growth over the auxin concentration range of 0.3 to 100 {mu}M. Growth inhibition was noted as a lengthening of the latent period and a decrease in the rate of an auxin-induced growth response. An acid growth response to pH 5 buffer in abraded sections was not impaired. The velocity of basipetal transport of ({sup 3}H)IAA through the coleoptile sections also was not inhibited by the compound, nor was uptake of ({sup 3}H)IAA. Similarly, the inhibitor does not appear to alter auxin-induced H{sup +} secretion. We suggest that the agent targets some other process necessary for auxin-dependent growth.

  20. Retinoic acid receptor alpha mediates growth inhibition by retinoids in human colon carcinoma HT29 cells.

    PubMed

    Nicke, B; Kaiser, A; Wiedenmann, B; Riecken, E O; Rosewicz, S

    1999-08-11

    Although retinoids have been suggested to inhibit chemically induced colon carcinogenesis, the molecular mechanisms underlying retinoid-mediated growth regulation in colon carcinoma cells are unknown. Therefore, we investigated the biological effects of retinoids on growth in HT29 colon carcinoma cells. All-trans retinoic acid (ATRA) treatment of HT29 cells resulted in a profound inhibition of anchorage-independent growth without biochemical or morphological evidence for induction of differentiation. Treatment with the selective RARalpha agonist Ro 40-6055 completely mimicked the effects of ATRA on growth and transactivation of a betaRAREx2-luciferase reporter construct, while RARbeta- and gamma-specific analogues were ineffective. Furthermore, ATRA-regulated growth and transactivation could be completely blocked by a RARalpha-selective receptor antagonist. Thus, ATRA potently inhibits anchorage-independent growth in HT29 cells and this effect is mainly if not exclusively mediated by the retinoic acid receptor alpha.

  1. Effect of plant sterols and tannins on Phytophthora ramorum growth and sporulation.

    PubMed

    Stong, Rachel A; Kolodny, Eli; Kelsey, Rick G; González-Hernández, M P; Vivanco, Jorge M; Manter, Daniel K

    2013-06-01

    Elicitin-mediated acquisition of plant sterols is required for growth and sporulation of Phytophthora spp. This study examined the interactions between elicitins, sterols, and tannins. Ground leaf tissue, sterols, and tannin-enriched extracts were obtained from three different plant species (California bay laurel, California black oak, and Oregon white oak) in order to evaluate the effect of differing sterol/tannin contents on Phytophthora ramorum growth. For all three species, high levels of foliage inhibited P. ramorum growth and sporulation, with a steeper concentration dependence for the two oak samples. Phytophthora ramorum growth and sporulation were inhibited by either phytosterols or tannin-enriched extracts. High levels of sterols diminished elicitin gene expression in P. ramorum; whereas the tannin-enriched extract decreased the amount of 'functional' or ELISA-detectable elicitin, but not gene expression. Across all treatment combinations, P. ramorum growth and sporulation correlated strongly with the amount of ELISA-detectable elicitin (R (2) = 0.791 and 0.961, respectively).

  2. Effect of plant sterols and tannins on Phytophthora ramorum growth and sporulation.

    PubMed

    Stong, Rachel A; Kolodny, Eli; Kelsey, Rick G; González-Hernández, M P; Vivanco, Jorge M; Manter, Daniel K

    2013-06-01

    Elicitin-mediated acquisition of plant sterols is required for growth and sporulation of Phytophthora spp. This study examined the interactions between elicitins, sterols, and tannins. Ground leaf tissue, sterols, and tannin-enriched extracts were obtained from three different plant species (California bay laurel, California black oak, and Oregon white oak) in order to evaluate the effect of differing sterol/tannin contents on Phytophthora ramorum growth. For all three species, high levels of foliage inhibited P. ramorum growth and sporulation, with a steeper concentration dependence for the two oak samples. Phytophthora ramorum growth and sporulation were inhibited by either phytosterols or tannin-enriched extracts. High levels of sterols diminished elicitin gene expression in P. ramorum; whereas the tannin-enriched extract decreased the amount of 'functional' or ELISA-detectable elicitin, but not gene expression. Across all treatment combinations, P. ramorum growth and sporulation correlated strongly with the amount of ELISA-detectable elicitin (R (2) = 0.791 and 0.961, respectively). PMID:23689874

  3. STS-95 space experiment for plant growth and development, and auxin polar transport.

    PubMed

    Ueda, J; Miyamoto, K; Yuda, T; Hoshino, T; Sato, K; Fujii, S; Kamigaichi, S; Izumi, R; Ishioka, N; Aizawa, S; Yoshizaki, I; Shimazu, T; Fukui, K

    2000-06-01

    The principal objective of the space experiment, BRIC-AUX on STS-95, was the integrated analysis of the growth and development of etiolated pea and maize seedlings in space, and the effect of microgravity conditions in space on auxin polar transport in the segments. Microgravity conditions in space strongly affected the growth and development of etiolated pea and maize seedlings. Etiolated pea and maize seedlings were leaned and curved during space flight, respectively. Finally the growth inhibition of these seedlings was also observed. Roots of some pea seedlings grew toward the aerial space of Plant Growth Chamber. Extensibilities of cell walls of the third internode of etiolated pea epicotyls and the top region of etiolated maize coleoptiles which were germinated and grown under microgravity conditions in space were significantly low. Activities of auxin polar transport in the second internode segments of etiolated pea seedlings and coleoptile segments of etiolated maize seedlings were significantly inhibited and extremely promoted, respectively, under microgravity conditions in space. These results strongly suggest that auxin polar transport as well as the growth and development of plants is controlled under gravity on the earth.

  4. Root foraging influences plant growth responses to earthworm foraging.

    PubMed

    Cameron, Erin K; Cahill, James F; Bayne, Erin M

    2014-01-01

    Interactions among the foraging behaviours of co-occurring animal species can impact population and community dynamics; the consequences of interactions between plant and animal foraging behaviours have received less attention. In North American forests, invasions by European earthworms have led to substantial changes in plant community composition. Changes in leaf litter have been identified as a critical indirect mechanism driving earthworm impacts on plants. However, there has been limited examination of the direct effects of earthworm burrowing on plant growth. Here we show a novel second pathway exists, whereby earthworms (Lumbricus terrestris L.) impact plant root foraging. In a mini-rhizotron experiment, roots occurred more frequently in burrows and soil cracks than in the soil matrix. The roots of Achillea millefolium L. preferentially occupied earthworm burrows, where nutrient availability was presumably higher than in cracks due to earthworm excreta. In contrast, the roots of Campanula rotundifolia L. were less likely to occur in burrows. This shift in root behaviour was associated with a 30% decline in the overall biomass of C. rotundifolia when earthworms were present. Our results indicate earthworm impacts on plant foraging can occur indirectly via physical and chemical changes to the soil and directly via root consumption or abrasion and thus may be one factor influencing plant growth and community change following earthworm invasion. More generally, this work demonstrates the potential for interactions to occur between the foraging behaviours of plants and soil animals and emphasizes the importance of integrating behavioural understanding in foraging studies involving plants.

  5. Root foraging influences plant growth responses to earthworm foraging.

    PubMed

    Cameron, Erin K; Cahill, James F; Bayne, Erin M

    2014-01-01

    Interactions among the foraging behaviours of co-occurring animal species can impact population and community dynamics; the consequences of interactions between plant and animal foraging behaviours have received less attention. In North American forests, invasions by European earthworms have led to substantial changes in plant community composition. Changes in leaf litter have been identified as a critical indirect mechanism driving earthworm impacts on plants. However, there has been limited examination of the direct effects of earthworm burrowing on plant growth. Here we show a novel second pathway exists, whereby earthworms (Lumbricus terrestris L.) impact plant root foraging. In a mini-rhizotron experiment, roots occurred more frequently in burrows and soil cracks than in the soil matrix. The roots of Achillea millefolium L. preferentially occupied earthworm burrows, where nutrient availability was presumably higher than in cracks due to earthworm excreta. In contrast, the roots of Campanula rotundifolia L. were less likely to occur in burrows. This shift in root behaviour was associated with a 30% decline in the overall biomass of C. rotundifolia when earthworms were present. Our results indicate earthworm impacts on plant foraging can occur indirectly via physical and chemical changes to the soil and directly via root consumption or abrasion and thus may be one factor influencing plant growth and community change following earthworm invasion. More generally, this work demonstrates the potential for interactions to occur between the foraging behaviours of plants and soil animals and emphasizes the importance of integrating behavioural understanding in foraging studies involving plants. PMID:25268503

  6. Root Foraging Influences Plant Growth Responses to Earthworm Foraging

    PubMed Central

    Cameron, Erin K.; Cahill, James F.; Bayne, Erin M.

    2014-01-01

    Interactions among the foraging behaviours of co-occurring animal species can impact population and community dynamics; the consequences of interactions between plant and animal foraging behaviours have received less attention. In North American forests, invasions by European earthworms have led to substantial changes in plant community composition. Changes in leaf litter have been identified as a critical indirect mechanism driving earthworm impacts on plants. However, there has been limited examination of the direct effects of earthworm burrowing on plant growth. Here we show a novel second pathway exists, whereby earthworms (Lumbricus terrestris L.) impact plant root foraging. In a mini-rhizotron experiment, roots occurred more frequently in burrows and soil cracks than in the soil matrix. The roots of Achillea millefolium L. preferentially occupied earthworm burrows, where nutrient availability was presumably higher than in cracks due to earthworm excreta. In contrast, the roots of Campanula rotundifolia L. were less likely to occur in burrows. This shift in root behaviour was associated with a 30% decline in the overall biomass of C. rotundifolia when earthworms were present. Our results indicate earthworm impacts on plant foraging can occur indirectly via physical and chemical changes to the soil and directly via root consumption or abrasion and thus may be one factor influencing plant growth and community change following earthworm invasion. More generally, this work demonstrates the potential for interactions to occur between the foraging behaviours of plants and soil animals and emphasizes the importance of integrating behavioural understanding in foraging studies involving plants. PMID:25268503

  7. Specific interactions between arbuscular mycorrhizal fungi and plant growth-promoting bacteria--as revealed by different combinations

    SciTech Connect

    Jaderlund, Lotta; Arthurson, Veronica; Granhall, Ulf; Jansson, Janet K.

    2008-05-15

    The interactions between two plant growth promoting rhizobacteria (PGPR), Pseudomonas fluorescens SBW25 and Paenibacillus brasilensis PB177, two arbuscular mycorrhizal (AM) fungi (Glomus mosseae and G. intraradices) and one pathogenic fungus (Microdochium nivale) were investigated on winter wheat (Triticum aestivum cultivar Tarso) in a greenhouse trial. PB177, but not SBW25, had strong inhibitory effects on M. nivale in dual culture plate assays. The results from the greenhouse experiment show very specific interactions; e.g. the two AM fungi react differently when interacting with the same bacteria on plants. G. intraradices (single inoculation or together with SBW25) increased plant dry weight on M. nivale infested plants, suggesting that the pathogenic fungus is counteracted by G. intraradices, but PB177 inhibited this positive effect. This is an example of two completely different reactions between the same AM fungus and two species of bacteria, previously known to enhance plant growth and inhibit pathogens. When searching for plant growth promoting microorganisms it is therefore important to test for the most suitable combination of plant, bacteria and fungi in order to get satisfactory plant growth benefits.

  8. Activated carbon decreases invasive plant growth by mediating plant-microbe interactions.

    PubMed

    Nolan, Nicole E; Kulmatiski, Andrew; Beard, Karen H; Norton, Jeanette M

    2014-01-01

    There is growing appreciation for the idea that plant-soil interactions (e.g. allelopathy and plant-microbe feedbacks) may explain the success of some non-native plants. Where this is the case, native plant restoration may require management tools that change plant-soil interactions. Activated carbon (AC) is one such potential tool. Previous research has shown the potential for high concentrations of AC to restore native plant growth to areas dominated by non-natives on a small scale (1 m × 1 m plots). Here we (i) test the efficacy of different AC concentrations at a larger scale (15 m × 15 m plots), (ii) measure microbial responses to AC treatment and (iii) use a greenhouse experiment to identify the primary mechanism, allelopathy versus microbial changes, through which AC impacts native and non-native plant growth. Three years after large-scale applications, AC treatments decreased non-native plant cover and increased the ratio of native to non-native species cover, particularly at concentrations >400 g m(-2). Activated carbon similarly decreased non-native plant growth in the greenhouse. This effect, however, was only observed in live soils, suggesting that AC effects were microbially mediated and not caused by direct allelopathy. Bacterial community analysis of field soils indicated that AC increased the relative abundance of an unidentified bacterium and an Actinomycetales and decreased the relative abundance of a Flavobacterium, suggesting that these organisms may play a role in AC effects on plant growth. Results support the idea that manipulations of plant-microbe interactions may provide novel and effective ways of directing plant growth and community development (e.g. native plant restoration). PMID:25387751

  9. Growth Inhibition and Apoptosis Induction of Salvia chloroleuca on MCF-7 Breast Cancer Cell Line.

    PubMed

    Tayarani-Najaran, Zahra; Asili, Javad; Aioubi, Ehsan; Emami, Seyed Ahmad

    2013-01-01

    Fragrant species of the genus Salvia have been attributed many medicinal properties, which include anticancer activity. In the present study, cytotoxic properties of total methanol extract of Salvia chloroleuca Rech. f. & Aellen and its fractions were investigated on MCF- 7, a breast carcinoma cell line. Malignant and non-malignant cells were cultured in RPMI medium and incubated with different concentrations of plant extracts. Cell viability was quantitated by 3-(4,5-dimethylthiazol-2-yl) -5-(3-carboxymethoxyphenyl) -2-(4-sulphophenyl) -2H-tetrazolium (MTS) assay. Apoptotic cells were determined using propidium iodide (PI) staining of DNA fragmentation by flow cytometry (sub-G1 peak). S. chloroleuca inhibited the growth of malignant cells in a dose-dependent manner. Among solvent fractions of S. chloroleuca, the n-hexane and methylene chloride fractions were found to be more toxic compared to other fractions. S. chloroleuca-induced a sub-G1 peak in flow cytometry histogram of treated cells compared to control and DNA fragmentation suggested the induction of apoptosis. Administration of N-acetyl cysteine and vitamin C two ROS scavengers also resulted in significant inhibition of cytotoxicity induced by S. chloroleuca. These results support a mechanism whereby S. chloroleuca induces apoptosis of MCF-7 human breast cells through a ROS-mediated pathway. PMID:24523759

  10. Effects of plant growth regulators on survival and recovery growth following cryopreservation.

    PubMed

    Turner, S R; Touchell, D H; Senaratna, T; Bunn, E; Tan, B; Dixon, K W

    2001-01-01

    Studies on the effects of plant growth regulators (PGRs) on survival, recovery and post-recovery growth of shoot apices following cryopreservation are limited. In this study, the effects of plant growth regulators in both the culture phase and the recovery phase of cryostorage were examined for the rare plant species, Anigozanthos viridis ssp terraspectans Hopper. Survival of shoot apices was not correlated to cytokinin or auxin treatments administered in culture media prior to cryostorage. In recovery media, the plant growth regulators, kinetin, zeatin (cytokinins), IAA, (auxin) and GA3 were examined for their effect following cryopreservation. It was found that the application of a combination of cytokinin and 0.5 microM GA3 from day zero was the most appropriate for obtaining vigorously growing plantlets following LN immersion. This combination proved to be more effective than basal medium, zeatin or kinetin treatments.

  11. Growth Characteristics of Rhizophagus clarus Strains and Their Effects on the Growth of Host Plants.

    PubMed

    Lee, Eun-Hwa; Eom, Ahn-Heum

    2015-12-01

    Arbuscular mycorrhizal fungi (AMF) are ubiquitous in the rhizosphere and form symbiotic relationships with most terrestrial plant roots. In this study, four strains of Rhizophagus clarus were cultured and variations in their growth characteristics owing to functional diversity and resultant effects on host plant were investigated. Growth characteristics of the studied R. clarus strains varied significantly, suggesting that AMF retain high genetic variability at the intraspecies level despite asexual lineage. Furthermore, host plant growth response to the R. clarus strains showed that genetic variability in AMF could cause significant differences in the growth of the host plant, which prefers particular genetic types of fungal strains. These results suggest that the intraspecific genetic diversity of AMF could be result of similar selective pressure and may be expressed at a functional level. PMID:26839504

  12. Growth Characteristics of Rhizophagus clarus Strains and Their Effects on the Growth of Host Plants

    PubMed Central

    Lee, Eun-Hwa

    2015-01-01

    Arbuscular mycorrhizal fungi (AMF) are ubiquitous in the rhizosphere and form symbiotic relationships with most terrestrial plant roots. In this study, four strains of Rhizophagus clarus were cultured and variations in their growth characteristics owing to functional diversity and resultant effects on host plant were investigated. Growth characteristics of the studied R. clarus strains varied significantly, suggesting that AMF retain high genetic variability at the intraspecies level despite asexual lineage. Furthermore, host plant growth response to the R. clarus strains showed that genetic variability in AMF could cause significant differences in the growth of the host plant, which prefers particular genetic types of fungal strains. These results suggest that the intraspecific genetic diversity of AMF could be result of similar selective pressure and may be expressed at a functional level. PMID:26839504

  13. The effect of differential growth rates across plants on spectral predictions of physiological parameters.

    PubMed

    Rapaport, Tal; Hochberg, Uri; Rachmilevitch, Shimon; Karnieli, Arnon

    2014-01-01

    Leaves of various ages and positions in a plant's canopy can present distinct physiological, morphological and anatomical characteristics, leading to complexities in selecting a single leaf for spectral representation of an entire plant. A fortiori, as growth rates between canopies differ, spectral-based comparisons across multiple plants--often based on leaves' position but not age--becomes an even more challenging mission. This study explores the effect of differential growth rates on the reflectance variability between leaves of different canopies, and its implication on physiological predictions made by widely-used spectral indices. Two distinct irrigation treatments were applied for one month, in order to trigger the formation of different growth rates between two groups of grapevines. Throughout the experiment, the plants were physiologically and morphologically monitored, while leaves from every part of their canopies were spectrally and histologically sampled. As the control vines were constantly developing new leaves, the water deficit plants were experiencing growth inhibition, resulting in leaves of different age at similar nodal position across the treatments. This modification of the age-position correlation was characterized by a near infrared reflectance difference between younger and older leaves, which was found to be exponentially correlated (R(2) = 0.98) to the age-dependent area of intercellular air spaces within the spongy parenchyma. Overall, the foliage of the control plant became more spectrally variable, creating complications for intra- and inter-treatment leaf-based comparisons. Of the derived indices, the Structure-Insensitive Pigment Index (SIPI) was found indifferent to the age-position effect, allowing the treatments to be compared at any nodal position, while a Normalized Difference Vegetation Index (NDVI)-based stomatal conductance prediction was substantially affected by differential growth rates. As various biotic and abiotic

  14. The Effect of Differential Growth Rates across Plants on Spectral Predictions of Physiological Parameters

    PubMed Central

    Rapaport, Tal; Hochberg, Uri; Rachmilevitch, Shimon; Karnieli, Arnon

    2014-01-01

    Leaves of various ages and positions in a plant's canopy can present distinct physiological, morphological and anatomical characteristics, leading to complexities in selecting a single leaf for spectral representation of an entire plant. A fortiori, as growth rates between canopies differ, spectral-based comparisons across multiple plants – often based on leaves' position but not age – becomes an even more challenging mission. This study explores the effect of differential growth rates on the reflectance variability between leaves of different canopies, and its implication on physiological predictions made by widely-used spectral indices. Two distinct irrigation treatments were applied for one month, in order to trigger the formation of different growth rates between two groups of grapevines. Throughout the experiment, the plants were physiologically and morphologically monitored, while leaves from every part of their canopies were spectrally and histologically sampled. As the control vines were constantly developing new leaves, the water deficit plants were experiencing growth inhibition, resulting in leaves of different age at similar nodal position across the treatments. This modification of the age-position correlation was characterized by a near infrared reflectance difference between younger and older leaves, which was found to be exponentially correlated (R2 = 0.98) to the age-dependent area of intercellular air spaces within the spongy parenchyma. Overall, the foliage of the control plant became more spectrally variable, creating complications for intra- and inter-treatment leaf-based comparisons. Of the derived indices, the Structure-Insensitive Pigment Index (SIPI) was found indifferent to the age-position effect, allowing the treatments to be compared at any nodal position, while a Normalized Difference Vegetation Index (NDVI)-based stomatal conductance prediction was substantially affected by differential growth rates. As various biotic and

  15. Gellan sulfate inhibits Plasmodium falciparum growth and invasion of red blood cells in vitro

    PubMed Central

    Recuenco, Frances Cagayat; Kobayashi, Kyousuke; Ishiwa, Akiko; Enomoto-Rogers, Yukiko; Fundador, Noreen Grace V.; Sugi, Tatsuki; Takemae, Hitoshi; Iwanaga, Tatsuya; Murakoshi, Fumi; Gong, Haiyan; Inomata, Atsuko; Horimoto, Taisuke; Iwata, Tadahisa; Kato, Kentaro

    2014-01-01

    Here, we assessed the sulfated derivative of the microbial polysaccharide gellan gum and derivatives of λ and κ-carrageenans for their ability to inhibit Plasmodium falciparum 3D7 and Dd2 growth and invasion of red blood cells in vitro. Growth inhibition was assessed by means of flow cytometry after a 96-h exposure to the inhibitors and invasion inhibition was assessed by counting ring parasites after a 20-h exposure to them. Gellan sulfate strongly inhibited invasion and modestly inhibited growth for both P. falciparum 3D7 and Dd2; both inhibitory effects exceeded those achieved with native gellan gum. The hydrolyzed λ-carrageenan and oversulfated κ-carrageenan were less inhibitory than their native forms. In vitro cytotoxicity and anticoagulation assays performed to determine the suitability of the modified polysaccharides for in vivo studies showed that our synthesized gellan sulfate had low cytotoxicity and anticoagulant activity. PMID:24740150

  16. Cultivable endophytic bacteria from leaf bases of Agave tequilana and their role as plant growth promoters.

    PubMed

    Martínez-Rodríguez, Julia del C; De la Mora-Amutio, Marcela; Plascencia-Correa, Luis A; Audelo-Regalado, Esmeralda; Guardado, Francisco R; Hernández-Sánchez, Elías; Peña-Ramírez, Yuri J; Escalante, Adelfo; Beltrán-García, Miguel J; Ogura, Tetsuya

    2014-01-01

    Agave tequilana Weber var. 'Azul' is grown for the production of tequila, inulin and syrup. Diverse bacteria inhabit plant tissues and play a crucial role for plant health and growth. In this study culturable endophytic bacteria were extracted from leaf bases of 100 healthy Agave tequilana plants. In plant tissue bacteria occurred at mean population densities of 3 million CFU/g of fresh plant tissue. Three hundred endophytic strains were isolated and 16s rDNA sequences grouped the bacteria into eight different taxa that shared high homology with other known sequences. Bacterial endophytes were identified as Acinectobacter sp., A. baumanii, A. bereziniae, Cronobacter sakazakii, Enterobacter hormaechei, Bacillus sp. Klebsiella oxytoca, Pseudomonas sp., Enterococcus casseliflavus, Leuconostoc mesenteroides subsp. mesenteroides and Gluconobacter oxydans. Isolates were confirmed to be plant growth promoting bacteria (PGPB) by their capacities for nitrogen fixation, auxin production, phosphate solubilization, or antagonism against Fusarium oxysporum AC132. E. casseliflavus JM47 and K. oxytoca JM26 secreted the highest concentrations of IAA. The endophyte Acinectobacter sp. JM58 exhibited the maximum values for nitrogen fixation and phosphate solubilization index (PSI). Inhibition of fungi was found in Pseudomonas sp. JM9p and K. oxytoca JM26. Bacterial endophytes show promise for use as bio-inoculants for agave cultivation. Use of endophytes to enhance cultivation of agave may be particularly important for plants produced by micropropagation techniques, where native endophytes may have been lost. PMID:25763038

  17. Cultivable endophytic bacteria from leaf bases of Agave tequilana and their role as plant growth promoters.

    PubMed

    Martínez-Rodríguez, Julia del C; De la Mora-Amutio, Marcela; Plascencia-Correa, Luis A; Audelo-Regalado, Esmeralda; Guardado, Francisco R; Hernández-Sánchez, Elías; Peña-Ramírez, Yuri J; Escalante, Adelfo; Beltrán-García, Miguel J; Ogura, Tetsuya

    2014-01-01

    Agave tequilana Weber var. 'Azul' is grown for the production of tequila, inulin and syrup. Diverse bacteria inhabit plant tissues and play a crucial role for plant health and growth. In this study culturable endophytic bacteria were extracted from leaf bases of 100 healthy Agave tequilana plants. In plant tissue bacteria occurred at mean population densities of 3 million CFU/g of fresh plant tissue. Three hundred endophytic strains were isolated and 16s rDNA sequences grouped the bacteria into eight different taxa that shared high homology with other known sequences. Bacterial endophytes were identified as Acinectobacter sp., A. baumanii, A. bereziniae, Cronobacter sakazakii, Enterobacter hormaechei, Bacillus sp. Klebsiella oxytoca, Pseudomonas sp., Enterococcus casseliflavus, Leuconostoc mesenteroides subsp. mesenteroides and Gluconobacter oxydans. Isolates were confirmed to be plant growth promoting bacteria (PGPB) by their capacities for nitrogen fixation, auxin production, phosphate solubilization, or antagonism against Fusarium oxysporum AC132. E. casseliflavus JM47 and K. oxytoca JM26 secreted the highest concentrations of IAA. The endophyte Acinectobacter sp. JM58 exhibited the maximum values for nitrogen fixation and phosphate solubilization index (PSI). Inhibition of fungi was found in Pseudomonas sp. JM9p and K. oxytoca JM26. Bacterial endophytes show promise for use as bio-inoculants for agave cultivation. Use of endophytes to enhance cultivation of agave may be particularly important for plants produced by micropropagation techniques, where native endophytes may have been lost.

  18. Cultivable endophytic bacteria from leaf bases of Agave tequilana and their role as plant growth promoters

    PubMed Central

    Martínez-Rodríguez, Julia del C.; la Mora-Amutio, Marcela De; Plascencia-Correa, Luis A.; Audelo-Regalado, Esmeralda; Guardado, Francisco R.; Hernández-Sánchez, Elías; Peña-Ramírez, Yuri J.; Escalante, Adelfo; Beltrán-García, Miguel J.; Ogura, Tetsuya

    2014-01-01

    Agave tequilana Weber var. ‘Azul’ is grown for the production of tequila, inulin and syrup. Diverse bacteria inhabit plant tissues and play a crucial role for plant health and growth. In this study culturable endophytic bacteria were extracted from leaf bases of 100 healthy Agave tequilana plants. In plant tissue bacteria occurred at mean population densities of 3 million CFU/g of fresh plant tissue. Three hundred endophytic strains were isolated and 16s rDNA sequences grouped the bacteria into eight different taxa that shared high homology with other known sequences. Bacterial endophytes were identified as Acinectobacter sp., A. baumanii, A. bereziniae, Cronobacter sakazakii, Enterobacter hormaechei, Bacillus sp. Klebsiella oxytoca, Pseudomonas sp., Enterococcus casseliflavus, Leuconostoc mesenteroides subsp. mesenteroides and Gluconobacter oxydans. Isolates were confirmed to be plant growth promoting bacteria (PGPB) by their capacities for nitrogen fixation, auxin production, phosphate solubilization, or antagonism against Fusarium oxysporum AC132. E. casseliflavus JM47 and K. oxytoca JM26 secreted the highest concentrations of IAA. The endophyte Acinectobacter sp. JM58 exhibited the maximum values for nitrogen fixation and phosphate solubilization index (PSI). Inhibition of fungi was found in Pseudomonas sp. JM9p and K. oxytoca JM26. Bacterial endophytes show promise for use as bio-inoculants for agave cultivation. Use of endophytes to enhance cultivation of agave may be particularly important for plants produced by micropropagation techniques, where native endophytes may have been lost. PMID:25763038

  19. Imatinib mesylate inhibits platelet derived growth factor stimulated proliferation of rheumatoid synovial fibroblasts

    SciTech Connect

    Sandler, Charlotta; Joutsiniemi, Saima; Lindstedt, Ken A.; Juutilainen, Timo; Kovanen, Petri T.; Eklund, Kari K. . E-mail: kari.eklund@hus.fi

    2006-08-18

    Synovial fibroblast is the key cell type in the growth of the pathological synovial tissue in arthritis. Here, we show that platelet-derived growth factor (PDGF) is a potent mitogen for synovial fibroblasts isolated from patients with rheumatoid arthritis. Inhibition of PDGF-receptor signalling by imatinib mesylate (1 {mu}M) completely abrogated the PDGF-stimulated proliferation and inhibited approximately 70% of serum-stimulated proliferation of synovial fibroblasts. Similar extent of inhibition was observed when PDGF was neutralized with anti-PDGF antibodies, suggesting that imatinib mesylate does not inhibit pathways other than those mediated by PDGF-receptors. No signs of apoptosis were detected in synovial fibroblasts cultured in the presence of imatinib. These results suggest that imatinib mesylate specifically inhibits PDGF-stimulated proliferation of synovial fibroblasts, and that inhibition of PDGF-receptors could represent a feasible target for novel antirheumatic therapies.

  20. Inhibition of Plasmodium falciparum dihydropteroate synthetase and growth in vitro by sulfa drugs.

    PubMed Central

    Zhang, Y; Meshnick, S R

    1991-01-01

    The Michaelis-Menten inhibitory constants (Kis) and the concentrations required for 50% inhibition of the Plasmodium falciparum dihydropteroate synthetase were determined for six sulfa drugs. These drugs inhibited the in vitro growth of P. falciparum (50% lethal concentration) at concentrations of 30 to 500 nM; these concentrations were 100 to 1,000 times lower than the concentrations required for 50% inhibition and Kis (6 to 500 microM). The uptake of p-aminobenzoic acid was not inhibited by the sulfa drugs. However, infected erythrocytes took up more labeled sulfamethoxazole than did uninfected erythrocytes. Thus, the concentration of sulfa drugs by malaria parasites may explain how sulfa drugs inhibit in vitro growth of parasites through the inhibition of dihydropteroate synthetase. PMID:2024960

  1. Plant extracts from Cameroonian medicinal plants strongly inhibit hepatitis C virus infection in vitro

    PubMed Central

    Galani, Borris R. T.; Sahuc, Marie-Emmanuelle; Njayou, Frederic N.; Deloison, Gaspard; Mkounga, Pierre; Feudjou, William F.; Brodin, Priscille; Rouillé, Yves; Nkengfack, Augustin E.; Moundipa, Paul Fewou; Séron, Karin

    2015-01-01

    According to some recent studies, Cameroon is one of the sub-Saharan African countries most affected by hepatitis C, with low access to the standard therapy based on the combination of pegylated interferon and ribavirin. A first ethnobotanical survey, conducted in the Western region of Cameroon, reported the use of several medicinal plants in traditional medicine for the healing of liver-related disorders. Crude organic extracts of five plants surveyed were prepared and their effect against hepatitis C virus (HCV) infection investigated. The HCV JFH1 strain cell culture system HCVcc was used. The antiviral activity was quantified by immunofluorescent labeling of HCV E1 envelope protein at 30 h post-infection in the presence of the plant extracts. Active compounds were then tested in time course infection experiments. Dose-response and cellular toxicity assays were also determined. Three extracts, methanol extracts from roots of Trichilia dregeana, stems of Detarium microcarpum and leaves of Phragmanthera capitata, showed anti-HCV activity, with half-maximal inhibitory concentration of 16.16, 1.42, and 13.17 μg/mL, respectively. Huh-7 cells were incubated with the extracts for 72 h and it appears that T. dregeana extract is not toxic up to 200 μg/mL, D. microcarpum up to 100 μg/mL and P. capitata up to 800 μg/mL. All the three extracts showed a strong inhibition of HCV entry and no effect on replication or secretion. Taken together, these results showed that extracts from Cameroonian medicinal plants are promising sources of anti-HCV agents. PMID:26029203

  2. Light-regulated plant growth and development.

    PubMed

    Kami, Chitose; Lorrain, Séverine; Hornitschek, Patricia; Fankhauser, Christian

    2010-01-01

    Plants are sessile and photo-autotrophic; their entire life cycle is thus strongly influenced by the ever-changing light environment. In order to sense and respond to those fluctuating conditions higher plants possess several families of photoreceptors that can monitor light from UV-B to the near infrared (far-red). The molecular nature of UV-B sensors remains unknown, red (R) and far-red (FR) light is sensed by the phytochromes (phyA-phyE in Arabidopsis) while three classes of UV-A/blue photoreceptors have been identified: cryptochromes, phototropins, and members of the Zeitlupe family (cry1, cry2, phot1, phot2, ZTL, FKF1, and LKP2 in Arabidopsis). Functional specialization within photoreceptor families gave rise to members optimized for a wide range of light intensities. Genetic and photobiological studies performed in Arabidopsis have shown that these light sensors mediate numerous adaptive responses (e.g., phototropism and shade avoidance) and developmental transitions (e.g., germination and flowering). Some physiological responses are specifically triggered by a single photoreceptor but in many cases multiple light sensors ensure a coordinated response. Recent studies also provide examples of crosstalk between the responses of Arabidopsis to different external factors, in particular among light, temperature, and pathogens. Although the different photoreceptors are unrelated in structure, in many cases they trigger similar signaling mechanisms including light-regulated protein-protein interactions or light-regulated stability of several transcription factors. The breath and complexity of this topic forced us to concentrate on specific aspects of photomorphogenesis and we point the readers to recent reviews for some aspects of light-mediated signaling (e.g., transition to flowering).

  3. Glycine decarboxylase controls photosynthesis and plant growth.

    PubMed

    Timm, Stefan; Florian, Alexandra; Arrivault, Stephanie; Stitt, Mark; Fernie, Alisdair R; Bauwe, Hermann

    2012-10-19

    Photorespiration makes oxygenic photosynthesis possible by scavenging 2-phosphoglycolate. Hence, compromising photorespiration impairs photosynthesis. We examined whether facilitating photorespiratory carbon flow in turn accelerates photosynthesis and found that overexpression of the H-protein of glycine decarboxylase indeed considerably enhanced net-photosynthesis and growth of Arabidopsis thaliana. At the molecular level, lower glycine levels confirmed elevated GDC activity in vivo, and lower levels of the CO(2) acceptor ribulose 1,5-bisphosphate indicated higher drain from CO(2) fixation. Thus, the photorespiratory enzyme glycine decarboxylase appears as an important feed-back signaller that contributes to the control of the Calvin-Benson cycle and hence carbon flow through both photosynthesis and photorespiration.

  4. Chloride anion transporters inhibit growth of methicillin-resistant Staphylococcus aureus (MRSA) in vitro.

    PubMed

    Share, Andrew I; Patel, Khushali; Nativi, Cristina; Cho, Eun J; Francesconi, Oscar; Busschaert, Nathalie; Gale, Philip A; Roelens, Stefano; Sessler, Jonathan L

    2016-06-18

    A series of aminopyrrolic receptors were tested as anion transporters using POPC liposome model membranes. Many were found to be effective Cl(-) transporters and to inhibit clinical strains of Staphylococcus aureus growth in vitro. The best transporters proved effective against the methicillin-resistant Staphylococcus aureus (MRSA) strains, Mu50 and HP1173. Tris-thiourea tren-based chloride transporters were also shown to inhibit the growth of S. aureus in vitro.

  5. Gravity sensing, a largely misunderstood trigger of plant orientated growth.

    PubMed

    Lopez, David; Tocquard, Kévin; Venisse, Jean-Stéphane; Legué, Valerie; Roeckel-Drevet, Patricia

    2014-01-01

    Gravity is a crucial environmental factor regulating plant growth and development. Plants have the ability to sense a change in the direction of gravity, which leads to the re-orientation of their growth direction, so-called gravitropism. In general, plant stems grow upward (negative gravitropism), whereas roots grow downward (positive gravitropism). Models describing the gravitropic response following the tilting of plants are presented and highlight that gravitropic curvature involves both gravisensing and mechanosensing, thus allowing to revisit experimental data. We also discuss the challenge to set up experimental designs for discriminating between gravisensing and mechanosensing. We then present the cellular events and the molecular actors known to be specifically involved in gravity sensing.

  6. Light-Mediated Hormonal Regulation of Plant Growth and Development.

    PubMed

    de Wit, Mieke; Galvão, Vinicius Costa; Fankhauser, Christian

    2016-04-29

    Light is crucial for plant life, and perception of the light environment dictates plant growth, morphology, and developmental changes. Such adjustments in growth and development in response to light conditions are often established through changes in hormone levels and signaling. This review discusses examples of light-regulated processes throughout a plant's life cycle for which it is known how light signals lead to hormonal regulation. Light acts as an important developmental switch in germination, photomorphogenesis, and transition to flowering, and light cues are essential to ensure light capture through architectural changes during phototropism and the shade avoidance response. In describing well-established links between light perception and hormonal changes, we aim to give insight into the mechanisms that enable plants to thrive in variable light environments.

  7. Inhibition of Growth of Salmonella by Native Flora of Broiler Chickens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction Some bacteria in the cecal microflora of broilers can inhibit colonization of chicks by Salmonella. Beneficial cecal bacteria may reduce Salmonella colonization by competing for nutrients and attachment sites or by producing metabolites that inhibit Salmonella growth. The purpose of th...

  8. The FGF-2-Derived Peptide FREG Inhibits Melanoma Growth In Vitro and In Vivo

    PubMed Central

    Aguzzi, Maria S; Faraone, Debora; D'Arcangelo, Daniela; De Marchis, Francesco; Toietta, Gabriele; Ribatti, Domenico; Parazzoli, Alberto; Colombo, Paolo; Capogrossi, Maurizio C; Facchiano, Antonio

    2011-01-01

    Previous data report that fibroblast growth factor-2 (FGF-2)-derived peptide FREG potently inhibits FGF-2-dependent angiogenesis in vitro and in vivo. Here, we show that FREG inhibits up to 70% in vitro growth and invasion/migration of smooth muscle and melanoma cells. Such inhibition is mediated by platelet-derived growth factor-receptor-α (PDGF-Rα); in fact, proliferation and migration were restored upon PDGF-Rα neutralization. Further experiments demonstrated that FREG interacts with PDGF-Rα both in vitro and in vivo and stimulates its phosphorylation. We have previously shown that overexpressing PDGF-Rα strongly inhibits melanoma growth in vivo; we, therefore, hypothesized that PDGF-Rα agonists may represent a novel tool to inhibit melanoma growth in vivo. To support this hypothesis, FREG was inoculated intravenously (i.v.) in a mouse melanoma model and markedly inhibited pulmonary metastases formation. Immunohistochemical analyses showed less proliferation, less angiogenesis, and more apoptosis in metastasized lungs upon FREG treatment, as compared to untreated controls. Finally, in preliminary acute toxicity studies, FREG showed no toxicity signs in healthy animals, and neither microscopic nor macroscopic toxicity at the liver, kidney, and lungs level. Altogether, these data indicate that FREG systemic treatment strongly inhibits melanoma metastases development and indicate for the first time that agonists of PDGF-Rα may control melanoma both in vitro and in vivo. PMID:20924364

  9. The FGF-2-derived peptide FREG inhibits melanoma growth in vitro and in vivo.

    PubMed

    Aguzzi, Maria S; Faraone, Debora; D'Arcangelo, Daniela; De Marchis, Francesco; Toietta, Gabriele; Ribatti, Domenico; Parazzoli, Alberto; Colombo, Paolo; Capogrossi, Maurizio C; Facchiano, Antonio

    2011-02-01

    Previous data report that fibroblast growth factor-2 (FGF-2)-derived peptide FREG potently inhibits FGF-2-dependent angiogenesis in vitro and in vivo. Here, we show that FREG inhibits up to 70% in vitro growth and invasion/migration of smooth muscle and melanoma cells. Such inhibition is mediated by platelet-derived growth factor-receptor-α (PDGF-Rα); in fact, proliferation and migration were restored upon PDGF-Rα neutralization. Further experiments demonstrated that FREG interacts with PDGF-Rα both in vitro and in vivo and stimulates its phosphorylation. We have previously shown that overexpressing PDGF-Rα strongly inhibits melanoma growth in vivo; we, therefore, hypothesized that PDGF-Rα agonists may represent a novel tool to inhibit melanoma growth in vivo. To support this hypothesis, FREG was inoculated intravenously (i.v.) in a mouse melanoma model and markedly inhibited pulmonary metastases formation. Immunohistochemical analyses showed less proliferation, less angiogenesis, and more apoptosis in metastasized lungs upon FREG treatment, as compared to untreated controls. Finally, in preliminary acute toxicity studies, FREG showed no toxicity signs in healthy animals, and neither microscopic nor macroscopic toxicity at the liver, kidney, and lungs level. Altogether, these data indicate that FREG systemic treatment strongly inhibits melanoma metastases development and indicate for the first time that agonists of PDGF-Rα may control melanoma both in vitro and in vivo. PMID:20924364

  10. Responses of some Nigerian vegetables of plant growth regulator treatments.

    PubMed

    Kadiri, M; Mukhtar, F; Agboola, D A

    1997-03-01

    The effects of single and combined growth regulator treatments of indole-3-acetic acid (IAA), gibberellic acid (GA3) and coconut milk on plant height, yield, chlorophyll and vitamin contents of Abelmoschus esculetus L and Solanum gilo L were investigated. The single growth regulator treatments consisted of 50mg/L, 100 mg/L of IAA and GA3 and 10%, 15% of coconut milk. In case of combined growth regulator treatments, the treatments were 100mg/L IAA + 100mg/L GA3, 100mg/L IAA + 15% coconut milk and 100mg/L GA3 + 15% coconut milk. Control vegetable plants were sprayed with water. Single treatments of 100mg/L IAA,100mg/L GA3. 10% and 15% coconut milk resulted in significantly increased plant height, chlorophyll contents and yield of A. esculentus, H. sabdariffa and S. gilo while only combined treatments of 100mg/L IAA + 10% coconut milk and 100mg/L GA3 + 15% coconut milk had such an effect on A. esculentus and S. gilo but not on H. sabdariffa. Moreover, singletreatments of 100mg/L GA3 and 15% coconut milk caused significantly higher vitamins A, B6 and C contents of treated plants whereas the combined treatments produced such an effect on only vitamin C contents of treated plants. Growth regulator treatments of 100mg/L GA3 and 15% coconut milk were consistently the best out of the entire growth regulator treatments tried with the treated plants having the greatest plant height, yield, chlorophyll and vitamin C contents. PMID:9404511

  11. Symbiotic regulation of plant growth, development and reproduction

    USGS Publications Warehouse

    Rodriguez, R.J.; Freeman, D. Carl; McArthur, E.D.; Kim, Y.-O.; Redman, R.S.

    2009-01-01

    The growth and development of rice (Oryzae sativa) seedlings was shown to be regulated epigenetically by a fungal endophyte. In contrast to un-inoculated (nonsymbiotic) plants, endophyte colonized (symbiotic) plants preferentially allocated resources into root growth until root hairs were well established. During that time symbiotic roots expanded at five times the rate observed in nonsymbiotic plants. Endophytes also influenced sexual reproduction of mature big sagebrush (Artemisia tridentata) plants. Two spatially distinct big sagebrush subspecies and their hybrids were symbiotic with unique fungal endophytes, despite being separated by only 380 m distance and 60 m elevation. A double reciprocal transplant experiment of parental and hybrid plants, and soils across the hybrid zone showed that fungal endophytes interact with the soils and different plant genotypes to confer enhanced plant reproduction in soil native to the endophyte and reduced reproduction in soil alien to the endophyte. Moreover, the most prevalent endophyte of the hybrid zone reduced the fitness of both parental subspecies. Because these endophytes are passed to the next generation of plants on seed coats, this interaction provides a selective advantage, habitat specificity, and the means of restricting gene flow, thereby making the hybrid zone stable, narrow and potentially leading to speciation. ?? 2009 Landes Bioscience.

  12. Di(2-ethylhexyl) phthalate inhibits antral follicle growth, induces atresia, and inhibits steroid hormone production in cultured mouse antral follicles

    PubMed Central

    Hannon, Patrick R.; Brannick, Katherine E.; Wang, Wei; Gupta, Rupesh K.; Flaws, Jodi A.

    2015-01-01

    Di(2-ethylhexyl) phthalate (DEHP) is a ubiquitous environmental toxicant found in consumer products that causes ovarian toxicity. Antral follicles are the functional ovarian units and must undergo growth, survival from atresia, and proper regulation of steroidogenesis to ovulate and produce hormones. Previous studies have determined that DEHP inhibits antral follicle growth and decreases estradiol levels in vitro; however, the mechanism by which DEHP elicits these effects is unknown. The present study tested the hypothesis that DEHP directly alters regulators of the cell cycle, apoptosis, and steroidogenesis to inhibit antral follicle functionality. Antral follicles from adult CD-1 mice were cultured with vehicle control or DEHP (1-100μg/ml) for 24-96 hr to establish the temporal effects of DEHP on the follicle. Following 24-96 hr of culture, antral follicles were subjected to gene expression analysis, and media were subjected to measurements of hormone levels. DEHP increased the mRNA levels of cyclin D2, cyclin dependent kinase 4, cyclin E1, cyclin A2, and cyclin B1 and decreased the levels of cyclin-dependent kinase inhibitor 1A prior to growth inhibition. Additionally, DEHP increased the mRNA levels of BCL2-associated agonist of cell death, BCL2-associated X protein, BCL2-related ovarian killer protein, B-cell leukemia/lymphoma 2, and Bcl2-like 10, leading to an increase in atresia. Further, DEHP decreased the levels of progesterone, androstenedione, and testosterone prior to the decrease in estradiol levels, with decreased mRNA levels of side-chain cleavage, 17α-hydorxylase-17,20-desmolase, 17β-hydroxysteroid dehydrogenase, and aromatase. Collectively, DEHP directly alters antral follicle functionality by inhibiting growth, inducing atresia, and inhibiting steroidogenesis. PMID:25701202

  13. Culture at a Higher Temperature Mildly Inhibits Cancer Cell Growth but Enhances Chemotherapeutic Effects by Inhibiting Cell-Cell Collaboration.

    PubMed

    Zhu, Shengming; Wang, Jiangang; Xie, Bingkun; Luo, Zhiguo; Lin, Xiukun; Liao, D Joshua

    2015-01-01

    Acute febrile infections have historically been used to treat cancer. To explore the underlying mechanism, we studied chronic effects of fever on cancer cell growth and chemotherapeutic efficacy in cell culture. We found that culturing cancer cells at 39°C mildly inhibited cell growth by arresting the cells at the G1 phase of the cell cycle. When cells were seeded in culture dishes at a lower density, e.g. about 1000-2000 cells per 35-mm dish, the growth inhibition was much greater, manifested as many fewer cell colonies in the 39°C dishes, compared with the results at a higher density seeding, e.g. 20,000 cells per dish, suggesting that cell-cell collaboration as the Allee effect in cell culture is inhibited at 39°C. Withdrawal of cells from serum enhanced the G1 arrest at 39°C and, for some cell lines such as A549 lung cancer cells, serum replenishment failed to quickly drive the cells from the G1 into the S and G2-M phases. Therapeutic effects of several chemotherapeutic agents, including clove bud extracts, on several cancer cell lines were more potent at 39°C than at 37°C, especially when the cells were seeded at a low density. For some cell lines and some agents, this enhancement is long-lasting, i.e. continuing after the cessation of the treatment. Collectively these results suggest that hyperthermia may inhibit cancer cell growth by G1 arrest and by inhibition of cell-cell collaboration, and may enhance the efficacy of several chemotherapeutic agents, an effect which may persist beyond the termination of chemotherapy. PMID:26495849

  14. Culture at a Higher Temperature Mildly Inhibits Cancer Cell Growth but Enhances Chemotherapeutic Effects by Inhibiting Cell-Cell Collaboration

    PubMed Central

    Zhu, Shengming; Wang, Jiangang; Xie, Bingkun; Luo, Zhiguo; Lin, Xiukun; Liao, D. Joshua

    2015-01-01

    Acute febrile infections have historically been used to treat cancer. To explore the underlying mechanism, we studied chronic effects of fever on cancer cell growth and chemotherapeutic efficacy in cell culture. We found that culturing cancer cells at 39°C mildly inhibited cell growth by arresting the cells at the G1 phase of the cell cycle. When cells were seeded in culture dishes at a lower density, e.g. about 1000–2000 cells per 35-mm dish, the growth inhibition was much greater, manifested as many fewer cell colonies in the 39°C dishes, compared with the results at a higher density seeding, e.g. 20,000 cells per dish, suggesting that cell-cell collaboration as the Allee effect in cell culture is inhibited at 39°C. Withdrawal of cells from serum enhanced the G1 arrest at 39°C and, for some cell lines such as A549 lung cancer cells, serum replenishment failed to quickly drive the cells from the G1 into the S and G2-M phases. Therapeutic effects of several chemotherapeutic agents, including clove bud extracts, on several cancer cell lines were more potent at 39°C than at 37°C, especially when the cells were seeded at a low density. For some cell lines and some agents, this enhancement is long-lasting, i.e. continuing after the cessation of the treatment. Collectively these results suggest that hyperthermia may inhibit cancer cell growth by G1 arrest and by inhibition of cell-cell collaboration, and may enhance the efficacy of several chemotherapeutic agents, an effect which may persist beyond the termination of chemotherapy. PMID:26495849

  15. Gravity related features of plant growth behavior studied with rotating machines

    NASA Technical Reports Server (NTRS)

    Brown, A. H.

    1996-01-01

    Research in plant physiology consists mostly of studies on plant growth because almost everything a plant does is done by growing. Most aspects of plant growth are strongly influenced by the earth's gravity vector. Research on those phenomena address scientific questions specifically about how plants use gravity to guide their growth processes.

  16. [Effects of arbuscular mycorrhiza fungi (AMF) on the plant growth, fruit yield, and fruit quality of cucumber under salt stress].

    PubMed

    Han, Bing; Guo, Shi-Rong; He, Chao-Xing; Yan, Yan; Yu, Xian-Chang

    2012-01-01

    By adopting organic substrate culture, and salt-sensitive cucumber variety 'Jinchun No. 2' was used as test material, this paper studied the effects of inoculating arbuscular mycorrhiza fungi (AMF) on the plant growth, fruit yield, and fruit quality of cucumber under salt stress. AMF-inoculation could effectively promote the plant growth and nutrient uptake, and improve the fruit yield and fruit nutrient quality, compared with ordinary cultivation. Under salt stress, the plant growth was inhibited, and the plant N, P, K, Cu, and Zn contents and K+/Na+ ratio, fruit yield, and fruit soluble protein, total sugar, vitamin C, and nitrate contents decreased, while inoculation with AMF could mitigate the inhibitory effect of salt stress on the plant growth, made the plant N, P, K, Cu, and Zn contents increased by 7.3%, 11.7%, 28.2%, 13.5%, and 9.9%, respectively, and made the plant K+/Na+ ratio, fruit yield, and fruit soluble protein, total sugar, and vitamin C contents have an obvious increase and the fruit nitrate content have a significant decrease. It was suggested that AMF could promote the plant growth and nutrient uptake of cucumber under salt stress, increase the plant salt-tolerance, and improve the fruit yield and its nutrient quality.

  17. Grafting of Cucumis sativus onto Cucurbita ficifolia leads to improved plant growth, increased light utilization and reduced accumulation of reactive oxygen species in chilled plants.

    PubMed

    Zhou, Yanhong; Zhou, Jie; Huang, Lifeng; Ding, Xiaotao; Shi, Kai; Yu, Jingquan

    2009-09-01

    The effects of chilling at 14 and 7 degrees C on plant growth, CO(2) assimilation, light allocation, photosynthetic electron flux and antioxidant metabolism were examined in cucumber (Cucumis sativus L. cv. Jinyan No. 4, CS) plants with figleaf gourd (Cucurbita ficifolia Bouché, CF) and cucumber as rootstocks, respectively. Growth inhibition by chilling at 7 degrees C was characterized by irreversible inhibition of CO(2) assimilation in grafted plants with cucumber as rootstock and scion (CS/CS) but this effect was significantly alleviated by grafting onto CF roots (CS/CF). Chilled CS/CF plants exhibited a higher photosynthetic activity and lower proportion of energy dissipation than chilled CS/CS plants. Chilling resulted in a greater decrease in the electron flux in photosystem (PS) II (J (PSII)) than the rate of energy dissipation either via light-dependent (J (NPQ)) or via constitutive thermal dissipation and fluorescence (J (f,D)) in CS/CS plants. In parallel with the reduction in J (PSII), electron flux to oxygenation (J (o)) and carboxylation by Rubisco (J (c)) all decreased significantly whilst alternative electron flux in PS II (J (a)) increased, especially in CS/CS plants. Moreover, CS/CF plants exhibited higher activity of antioxidant enzymes, lower antioxidant content and less membrane peroxidation relative to CS/CS plants after chilling.

  18. Phytotoxic activity of Ocimum tenuiflorum extracts on germination and seedling growth of different plant species.

    PubMed

    Islam, A K M Mominul; Kato-Noguchi, Hisashi

    2014-01-01

    Phytotoxic activity of Ocimum tenuiflorum (Lamiaceae) plant extracts was investigated against the germination and seedling growth of cress (Lepidium sativum), lettuce (Lactuca sativa), alfalfa (Medicago sativa), Italian ryegrass (Lolium multiflorum), barnyard grass (Echinochloa crus-galli), and timothy (Phleum pratense) at four different concentrations. The plant extracts at concentrations greater than 30 mg dry weight equivalent extract mL(-1) reduced significantly the total germination percent (GP), germination index (GI), germination energy (GE), speed of emergence (SE), seedling vigour index (SVI), and coefficient of the rate of germination (CRG) of all test species except barnyard grass and GP of lettuce. In contrast, time required for 50% germination (T 50) and mean germination time (MGT) were increased at the same or higher than this concentration. The increasing trend of T 50 and MGT and the decreasing trend of other indices indicated a significant inhibition or delay of germination of the test species by O. tenuiflorum plant extracts and vice versa. In addition, the shoot and root growth of all test species were significantly inhibited by the extracts at concentrations greater than 10 mg dry weight equivalent extract mL(-1). The I 50 values for shoot and root growth were ranged from 26 to 104 mg dry weight equivalent extract mL(-1). Seedling growth was more sensitive to the extracts compared to seed germination. Results of this study suggest that O. tenuiflorum plant extracts have phytotoxic properties and thus contain phytotoxic substances. Isolation and characterization of those substances from this plant may act as a tool for new natural, biodegradable herbicide development to control weeds. PMID:25032234

  19. Phytotoxic Activity of Ocimum tenuiflorum Extracts on Germination and Seedling Growth of Different Plant Species

    PubMed Central

    2014-01-01

    Phytotoxic activity of Ocimum tenuiflorum (Lamiaceae) plant extracts was investigated against the germination and seedling growth of cress (Lepidium sativum), lettuce (Lactuca sativa), alfalfa (Medicago sativa), Italian ryegrass (Lolium multiflorum), barnyard grass (Echinochloa crus-galli), and timothy (Phleum pratense) at four different concentrations. The plant extracts at concentrations greater than 30 mg dry weight equivalent extract mL−1 reduced significantly the total germination percent (GP), germination index (GI), germination energy (GE), speed of emergence (SE), seedling vigour index (SVI), and coefficient of the rate of germination (CRG) of all test species except barnyard grass and GP of lettuce. In contrast, time required for 50% germination (T50) and mean germination time (MGT) were increased at the same or higher than this concentration. The increasing trend of T50 and MGT and the decreasing trend of other indices indicated a significant inhibition or delay of germination of the test species by O. tenuiflorum plant extracts and vice versa. In addition, the shoot and root growth of all test species were significantly inhibited by the extracts at concentrations greater than 10 mg dry weight equivalent extract mL−1. The I50 values for shoot and root growth were ranged from 26 to 104 mg dry weight equivalent extract mL−1. Seedling growth was more sensitive to the extracts compared to seed germination. Results of this study suggest that O. tenuiflorum plant extracts have phytotoxic properties and thus contain phytotoxic substances. Isolation and characterization of those substances from this plant may act as a tool for new natural, biodegradable herbicide development to control weeds. PMID:25032234

  20. Influence of Atmospheric Pressure Torch Plasma Irradiation on Plant Growth

    NASA Astrophysics Data System (ADS)

    Akiyoshi, Yusuke; Hayashi, Nobuya; Kitazaki, Satoshi; Koga, Kazunori; Shiratani, Masaharu

    2011-10-01

    Growth stimulation characteristics of plants seeds are investigated by an atmospheric discharge irradiation into plasma seeds. Atmospheric pressure plasma torch is consisted of alumina ceramics tube and the steel mesh electrodes wind inside and outside of the tube. When AC high voltage (8 kHz) is applied to the electrode gap, the barrier discharge plasma is produced inside the alumina ceramics tube. The barrier discharge plasma is blown outside with the gas flow in ceramics tube. Radish sprouts seeds locate at 1 cm from the torch edge. The growth stimulation was observed in the length of a stem and a root after the plasma irradiation. The stem length increases approximately 2.8 times at the cultivation time of 24 h. And the growth stimulation effect is found to be maintained for 40 h, after sowing seeds. The mechanism of the growth stimulation would be the redox reaction inside plant cells induced by oxygen radicals.

  1. Tuning plant signaling and growth to survive salt.

    PubMed

    Julkowska, Magdalena M; Testerink, Christa

    2015-09-01

    Salinity is one of the major abiotic factors threatening food security worldwide. Recently, our understanding of early processes underlying salinity tolerance has expanded. In this review, early signaling events, such as phospholipid signaling, calcium ion (Ca(2+)) responses, and reactive oxygen species (ROS) production, together with salt stress-induced abscisic acid (ABA) accumulation, are brought into the context of long-term salt stress-specific responses and alteration of plant growth. Salt-induced quiescent and recovery growth phases rely on modification of cell cycle activity, cell expansion, and cell wall extensibility. The period of initial growth arrest varies among different organs, leading to altered plant morphology. Studying stress-induced changes in growth dynamics can be used for screening to discover novel genes contributing to salt stress tolerance in model species and crops. PMID:26205171

  2. Paracrine expression of a native soluble vascular endothelial growth factor receptor inhibits tumor growth, metastasis, and mortality rate

    PubMed Central

    Goldman, Corey K.; Kendall, Richard L.; Cabrera, Gustavo; Soroceanu, Liliana; Heike, Yuji; Gillespie, G. Yancey; Siegal, Gene P.; Mao, Xianzhi; Bett, Andrew J.; Huckle, William R.; Thomas, Kenneth A.; Curiel, David T.

    1998-01-01

    Vascular endothelial growth factor (VEGF) is a potent and selective vascular endothelial cell mitogen and angiogenic factor. VEGF expression is elevated in a wide variety of solid tumors and is thought to support their growth by enhancing tumor neovascularization. To block VEGF-dependent angiogenesis, tumor cells were transfected with cDNA encoding the native soluble FLT-1 (sFLT-1) truncated VEGF receptor which can function both by sequestering VEGF and, in a dominant negative fashion, by forming inactive heterodimers with membrane-spanning VEGF receptors. Transient transfection of HT-1080 human fibrosarcoma cells with a gene encoding sFLT-1 significantly inhibited their implantation and growth in the lungs of nude mice following i.v. injection and their growth as nodules from cells injected s.c. High sFLT-1 expressing stably transfected HT-1080 clones grew even slower as s.c. tumors. Finally, survival was significantly prolonged in mice injected intracranially with human glioblastoma cells stably transfected with the sflt-1 gene. The ability of sFLT-1 protein to inhibit tumor growth is presumably attributable to its paracrine inhibition of tumor angiogenesis in vivo, since it did not affect tumor cell mitogenesis in vitro. These results not only support VEGF receptors as antiangiogenic targets but also demonstrate that sflt-1 gene therapy might be a feasible approach for inhibiting tumor angiogenesis and growth. PMID:9671758

  3. Growth inhibition of Erwinia amylovora and related Erwinia species by neutralized short‑chain fatty acids.

    PubMed

    Konecki, Katrin; Gernold, Marina; Wensing, Annette; Geider, Klaus

    2013-11-01

    Short-chain fatty acids (SCFAs) are used to preserve food and could be a tool for control of fire blight caused by Erwinia amylovora on apple, pear and related rosaceous plants. Neutralized acids were added to buffered growth media at 0.5–75 mM and tested at pHs ranging from 6.8 to 5.5. Particularly at low pH, SCFAs with a chain length exceeding that of acetic acid such as propionic acid were effective growth inhibitors of E. amylovora possibly due to uptake of free acid and its intracellular accumulation. We also observed high inhibition with monochloroacetic acid. An E. billingiae strain was as sensitive to the acids as E. amylovora or E. tasmaniensis. Fire blight symptoms on pear slices were reduced when the slices were pretreated with neutralized propionic acid. Propionic acid is well water soluble and could be applied in orchards as a control agent for fire blight. PMID:24077735

  4. Mechanical stress regulation of plant growth and development

    NASA Technical Reports Server (NTRS)

    Mitchell, C. A.; Myers, P. N.

    1995-01-01

    The authors introduce the chapter with a discussion of lessons from nature, agriculture, and landscapes; terms and definitions; and an historical perspective of mechanical stress regulation of plant growth and development. Topics include developmental responses to mechanical stress; mechanical stress-environment interactions; metabolic, productivity, and compositional changes; hormonal involvement; mechanoperception and early transduction mechanisms; applications in agriculture; and research implications. The discussion of hormonal involvement in mechanical stress physiology includes ethylene, auxin, gibberellins, and other phytohormones. The discussion of applications in agriculture examines windbreaks, nursery practices, height control and conditioning, and enhancement of growth and productivity. Implications for research are related to handling plant materials, space biology, and future research needs.

  5. Information Integration and Communication in Plant Growth Regulation.

    PubMed

    Chaiwanon, Juthamas; Wang, Wenfei; Zhu, Jia-Ying; Oh, Eunkyoo; Wang, Zhi-Yong

    2016-03-10

    Plants are equipped with the capacity to respond to a large number of diverse signals, both internal ones and those emanating from the environment, that are critical to their survival and adaption as sessile organisms. These signals need to be integrated through highly structured intracellular networks to ensure coherent cellular responses, and in addition, spatiotemporal actions of hormones and peptides both orchestrate local cell differentiation and coordinate growth and physiology over long distances. Further, signal interactions and signaling outputs vary significantly with developmental context. This review discusses our current understanding of the integrated intracellular and intercellular signaling networks that control plant growth.

  6. Use of Hydrogen Peroxide to Disinfect Hydroponic Plant Growth Systems

    NASA Technical Reports Server (NTRS)

    Barta, Daniel J.; Henderson, Keith

    2000-01-01

    Hydrogen peroxide was studied as an alternative to conventional bleach and rinsing methods to disinfect hydroponic plant growth systems. A concentration of 0.5% hydrogen peroxide was found to be effective. Residual hydrogen peroxide can be removed from the system by repeated rinsing or by flowing the solution through a platinum on aluminum catalyst. Microbial populations were reduced to near zero immediately after treatment but returned to pre-disinfection levels 2 days after treatment. Treating nutrient solution with hydrogen peroxide and planting directly into trays being watered with the nutrient solution without replenishment, was found to be detrimental to lettuce germination and growth.

  7. Information Integration and Communication in Plant Growth Regulation.

    PubMed

    Chaiwanon, Juthamas; Wang, Wenfei; Zhu, Jia-Ying; Oh, Eunkyoo; Wang, Zhi-Yong

    2016-03-10

    Plants are equipped with the capacity to respond to a large number of diverse signals, both internal ones and those emanating from the environment, that are critical to their survival and adaption as sessile organisms. These signals need to be integrated through highly structured intracellular networks to ensure coherent cellular responses, and in addition, spatiotemporal actions of hormones and peptides both orchestrate local cell differentiation and coordinate growth and physiology over long distances. Further, signal interactions and signaling outputs vary significantly with developmental context. This review discusses our current understanding of the integrated intracellular and intercellular signaling networks that control plant growth. PMID:26967291

  8. Use of lunar regolith as a substrate for plant growth

    NASA Technical Reports Server (NTRS)

    Ming, D. W.; Henninger, D. L.

    1994-01-01

    Regenerative Life Support Systems (RLSS) will be required to regenerate air, water, and wastes, and to produce food for human consumption during long-duration missions to the Moon and Mars. It may be possible to supplement some of the materials needed for a lunar RLSS from resources on the Moon. Natural materials at the lunar surface may be used for a variety of lunar RLSS needs, including (1) soils or solid-support substrates for plant growth, (2) sources for extraction of essential, plant-growth nutrients, (3) substrates for microbial populations in the degradation of wastes, (4) sources of O2 and H2, which may be used to manufacture water, (5) feed stock materials for the synthesis of useful minerals (e.g., molecular sieves), and (6) shielding materials surrounding the outpost structure to protect humans, plants, and microorganisms from harmful radiation. Use of indigenous lunar regolith as a terrestrial-like soil for plant growth could offer a solid support substrate, buffering capacity, nutrient source/storage/retention capabilities, and should be relatively easy to maintain. The lunar regolith could, with a suitable microbial population, play a role in waste renovation; much like terrestrial waste application directly on soils. Issues associated with potentially toxic elements, pH, nutrient availability, air and fluid movement parameters, and cation exchange capacity of lunar regolith need to be addressed before lunar materials can be used effectively as soils for plant growth.

  9. Designing Extraterrestrial Plant Growth Habitats with Low Pressure Atmospheres

    NASA Technical Reports Server (NTRS)

    Corey, Kenneth A.

    2002-01-01

    In-situ resource utilization, provision of human life support requirements by bioregenerative methods, and engineering constraints for construction and deployment of plant growth structures on the surface of Mars all suggest the need for plant growth studies at hypobaric pressures. Past work demonstrated that plants will likely tolerate and grow at pressures at or below 10 kPa. Based upon this premise, concepts are developed for the design of reduced pressure atmospheres in lightweight, inflatable structures for plant growth systems on Mars with the goals of maximizing design simplicity and the use of local resources. A modular pod design is proposed as it could be integrated with large-scale production systems. Atmospheric modification of pod clusters would be based upon a pulse and scrub system using mass flow methods for atmospheric transport. A specific modification and control scenario is developed for a lettuce pod to illustrate the dynamics of carbon dioxide and oxygen exchange within a pod. Considerations of minimal atmospheric crop requirements will aid in the development of engineering designs and strategies for extraterrestrial plant growth structures that employ rarefied atmospheres.

  10. Designing Extraterrestrial Plant Growth Habitats With Low Pressure Atmospheres

    NASA Technical Reports Server (NTRS)

    Corey, Kenneth A.

    2001-01-01

    In-situ resource utilization, provision of human life support requirements by bioregenerative methods, and engineering constraints for construction and deployment of plant growth structures on the surface of Mars all suggest the need for plant growth studies at hypobaric pressures. Past work demonstrated that plants will likely tolerate and grow at pressures at or below 10 kPa. Based upon this premise, concepts are developed for the design of reduced pressure atmospheres in lightweight, inflatable structures for plant growth systems on Mars with the goals of maximizing design simplicity and the use of local resources. A modular pod design is proposed as it could be integrated with large-scale production systems. Atmospheric modification of pod clusters would be based upon a pulse and scrub system using mass flow methods for atmospheric transport. A specific modification and control scenario is developed for a lettuce pod to illustrate the dynamics of carbon dioxide and oxygen exchange within a pod. Considerations of minimal atmospheric crop requirements will aid in the development of engineering designs and strategies for extraterrestrial plant growth structures that employ rarefied atmospheres.

  11. Use of lunar regolith as a substrate for plant growth

    NASA Astrophysics Data System (ADS)

    Ming, D. W.; Henninger, D. L.

    1994-11-01

    Regenerative Life Support Systems (RLSS) will be required to regenerate air, water, and wastes, and to produce food for human consumption during long-duration missions to the Moon and Mars. It may be possible to supplement some of the materials needed for a lunar RLSS from resources on the Moon. Natural materials at the lunar surface may be used for a variety of lunar RLSS needs, including (i) soils or solid-support substrates for plant growth, (ii) sources for extraction of essential, plant-growth nutrients, (iii) substrates for microbial populations in the degradation of wastes, (iv) sources of O2 and H2, which may be used to manufacture water, (v) feed stock materials for the synthesis of useful minerals (e.g., molecular sieves), and (vi) shielding materials surrounding the outpost structure to protect humans, plants, and microorganism from harmful radiation. Use of indigenous lunar regolith as a terrestrial-like soil for plant growth could offer a solid support substrate, buffering capacity, nutrient source/storage/retention capabilities, and should be relatively easy to maintain. The lunar regolith could, with a suitable microbial population, play a role in waste renovation; much like terrestrial waste application directly on soils. Issues associated with potentially toxic elements, pH, nutrient availability, air and fluid movement parameters, and cation exchange capacity of lunar regolith need to be addressed before lunar materials can be used effectively as soils for plant growth.

  12. Plant Growth-Promoting Bacteria: Mechanisms and Applications

    PubMed Central

    Glick, Bernard R.

    2012-01-01

    The worldwide increases in both environmental damage and human population pressure have the unfortunate consequence that global food production may soon become insufficient to feed all of the world's people. It is therefore essential that agricultural productivity be significantly increased within the next few decades. To this end, agricultural practice is moving toward a more sustainable and environmentally friendly approach. This includes both the increasing use of transgenic plants and plant growth-promoting bacteria as a part of mainstream agricultural practice. Here, a number of the mechanisms utilized by plant growth-promoting bacteria are discussed and considered. It is envisioned that in the not too distant future, plant growth-promoting bacteria (PGPB) will begin to replace the use of chemicals in agriculture, horticulture, silviculture, and environmental cleanup strategies. While there may not be one simple strategy that can effectively promote the growth of all plants under all conditions, some of the strategies that are discussed already show great promise. PMID:24278762

  13. Use of lunar regolith as a substrate for plant growth.

    PubMed

    Ming, D W; Henninger, D L

    1994-01-01

    Regenerative Life Support Systems (RLSS) will be required to regenerate air, water, and wastes, and to produce food for human consumption during long-duration missions to the Moon and Mars. It may be possible to supplement some of the materials needed for a lunar RLSS from resources on the Moon. Natural materials at the lunar surface may be used for a variety of lunar RLSS needs, including (i) soils or solid-support substrates for plant growth, (ii) sources for extraction of essential, plant-growth nutrients, (iii) substrates for microbial populations in the degradation of wastes, (iv) sources of O2 and H2, which may be used to manufacture water, (v) feed stock materials for the synthesis of useful minerals (e.g., molecular sieves), and (vi) shielding materials surrounding the outpost structure to protect humans, plants, and microorganisms from harmful radiation. Use of indigenous lunar regolith as a terrestrial-like soil for plant growth could offer a solid support substrate, buffering capacity, nutrient source/storage/retention capabilities, and should be relatively easy to maintain. The lunar regolith could, with a suitable microbial population, play a role in waste renovation; much like terrestrial waste application directly on soils. Issues associated with potentially toxic elements, pH, nutrient availability, air and fluid movement parameters, and cation exchange capacity of lunar regolith need to be addressed before lunar materials can be used effectively as soils for plant growth. PMID:11538023

  14. Use of lunar regolith as a substrate for plant growth.

    PubMed

    Ming, D W; Henninger, D L

    1994-01-01

    Regenerative Life Support Systems (RLSS) will be required to regenerate air, water, and wastes, and to produce food for human consumption during long-duration missions to the Moon and Mars. It may be possible to supplement some of the materials needed for a lunar RLSS from resources on the Moon. Natural materials at the lunar surface may be used for a variety of lunar RLSS needs, including (i) soils or solid-support substrates for plant growth, (ii) sources for extraction of essential, plant-growth nutrients, (iii) substrates for microbial populations in the degradation of wastes, (iv) sources of O2 and H2, which may be used to manufacture water, (v) feed stock materials for the synthesis of useful minerals (e.g., molecular sieves), and (vi) shielding materials surrounding the outpost structure to protect humans, plants, and microorganisms from harmful radiation. Use of indigenous lunar regolith as a terrestrial-like soil for plant growth could offer a solid support substrate, buffering capacity, nutrient source/storage/retention capabilities, and should be relatively easy to maintain. The lunar regolith could, with a suitable microbial population, play a role in waste renovation; much like terrestrial waste application directly on soils. Issues associated with potentially toxic elements, pH, nutrient availability, air and fluid movement parameters, and cation exchange capacity of lunar regolith need to be addressed before lunar materials can be used effectively as soils for plant growth.

  15. The Mars Plant Growth Experiment and Implications for Planetary Protection

    NASA Astrophysics Data System (ADS)

    Smith, Heather

    Plants are the ultimate and necessary solution for O2 production at a human base on Mars. Currently it is unknown if seeds can germinate on the Martian surface. The Mars Plant growth experiment (MPX) is a proposal for the first step in the development of a plant- based O2 production system by demonstrating plant germination and growth on the Martian surface. There is currently no planetary protection policy in place that covers plants on the Martian surface. We describe a planetary protection plan in compliance with NASA and COSPAR policy for a closed plant growth chamber on a Mars rover. We divide the plant growth chamber into two categories for planetary protection, the Outside: the outside of the chamber exposed to the Martian environment, and the Inside: the inside of the chamber which is sealed off from Mars atmosphere and contains the plant seeds and ancillary components for seed growth. We will treat outside surfaces of the chamber as other outside surfaces on the rover, wiped with a mixture of isopropyl alcohol and water as per Category IVb planetary protection requirements. All internal components of the MPX except the seeds and camera (including the water system, the plant growth stage and interior surface walls) will be sterilized by autoclave and subjected to sterilizing dry heat at a temperature of 125°C at an absolute humidity corresponding to a relative humidity of less than 25 percent referenced to the standard conditions of 0°C and 760 torr pressure. The seeds and internal compartments of the MPX in contact with the growth media will be assembled and tested to be free of viable microbes. MPX, once assembled, cannot survive Dry Heat Microbial Reduction. The camera with the radiation and CO2 sensors will be sealed in their own container and vented through HEPA filters. The seeds will be vernalized (microbe free) as per current Space Station methods described by Paul et al. 2001. Documentation of the lack of viable microbes on representative seeds

  16. Inhibition of Mycobacterial Growth In Vitro following Primary but Not Secondary Vaccination with Mycobacterium bovis BCG

    PubMed Central

    Fletcher, Helen A.; Tanner, Rachel; Wallis, Robert S.; Meyer, Joel; Manjaly, Zita-Rose; Harris, Stephanie; Satti, Iman; Silver, Richard F.; Hoft, Dan; Kampmann, Beate; Walker, K. Barry; Dockrell, Hazel M.; Fruth, Uli; Barker, Lew; McShane, Helen

    2013-01-01

    Despite the widespread use of the Mycobacterium bovis BCG vaccine, there are more than 9 million new cases of tuberculosis (TB) every year, and there is an urgent need for better TB vaccines. TB vaccine candidates are selected for evaluation based in part on the detection of an antigen-specific gamma interferon (IFN-γ) response. The measurement of mycobacterial growth in blood specimens obtained from subjects immunized with investigational TB vaccines may be a better in vitro correlate of in vivo vaccine efficacy. We performed a clinical study with 30 United Kingdom adults who were followed for 6 months to evaluate the abilities of both a whole-blood- and a novel peripheral blood mononuclear cell (PBMC)-based mycobacterial growth inhibition assay to measure a response to primary vaccination and revaccination with BCG. Using cryopreserved PBMCs, we observed a significant improvement in mycobacterial growth inhibition following primary vaccination but no improvement in growth inhibition following revaccination with BCG (P < 0.05). Mycobacterial growth inhibition following primary BCG vaccination was not correlated with purified protein derivative (PPD) antigen-specific IFN-γ enzyme-linked immunospot (ELISPOT) responses. We demonstrate that a mycobacterial growth inhibition assay can detect improved capacity to control growth following primary immunization, but not revaccination, with BCG. This is the first study to demonstrate that an in vitro growth inhibition assay can identify a difference in vaccine responses by comparing both primary and secondary BCG vaccinations, suggesting that in vitro growth inhibition assays may serve as better surrogates of clinical efficacy than the assays currently used for the assessment of candidate TB vaccines. PMID:23986316

  17. Inhibition of ethylene production by putrescine alleviates aluminium-induced root inhibition in wheat plants

    PubMed Central

    Yu, Yan; Jin, Chongwei; Sun, Chengliang; Wang, Jinghong; Ye, Yiquan; Zhou, Weiwei; Lu, Lingli; Lin, Xianyong

    2016-01-01

    Inhibition of root elongation is one of the most distinct symptoms of aluminium (Al) toxicity. Although putrescine (Put) has been identified as an important signaling molecule involved in Al tolerance, it is yet unknown how Put mitigates Al-induced root inhibition. Here, the possible mechanism was investigated by using two wheat genotypes differing in Al resistance: Al-tolerant Xi Aimai-1 and Al-sensitive Yangmai-5. Aluminium caused more root inhibition in Yangmai-5 and increased ethylene production at the root apices compared to Xi Aimai-1, whereas the effects were significantly reversed by ethylene biosynthesis inhibitors. The simultaneous exposure of wheat seedlings to Al and ethylene donor, ethephon, or ethylene biosynthesis precursor, 1-aminocyclopropane-1-carboxylic acid (ACC), increased ethylene production and aggravated root inhibition, which was more pronounced in Xi Aimai-1. In contrast, Put treatment decreased ethylene production and alleviated Al-induced root inhibition in both genotypes, and the effects were more conspicuous in Yangmai-5. Furthermore, our results indicated that Al-induced ethylene production was mediated by ACC synthase (ACS) and ACC oxidase, and that Put decreased ethylene production by inhibiting ACS. Altogether, these findings indicate that ethylene is involved in Al-induced root inhibition and this process could be alleviated by Put through inhibiting ACS activity. PMID:26744061

  18. Physiological and growth responses of C3 and C4 plants at the Pleistocene glacial maximum

    SciTech Connect

    Strain, B.R.

    1995-06-01

    A C3 plant (Abutilon theophrasti) and a C4 plant (Amaranthus retroflexus) were grown from seed in the Duke University Phytotron under four CO2 concentrations (15 Pa, below the Pleistocene minimum), 27 Pa (pre-industrial), 35 Pa (current), and 70 Pa (future) to examine photosynthetic, growth and reproduction responses of annual plants to historic and future levels of CO2. Net photosynthesis and growth were greatly inhibited at 15 Pa and greatly stimulated at 70 Pa. in the C3 Abutilon but only slightly affected in the C4 Amaranthus. Flower bud initiation was not affected by CO2 treatment in either species but all flower buds in 15 Pa CO2 aborted in the C3 within two days of appearance while no inhibition of reproduction was observed at low CO2 in the C4. Differences in physiology, growth and reproduction to the low levels of atmospheric CO2 of the Pleistocene suggest that competitive interactions of C3 and C4 annuals have changed through geologic time. A major question concerning the survival and evolution of obligate C3 annuals during the CO2 minima of the Pleistocene is raised by the results of this study.

  19. Hypergravity inhibits elongation growth of azuki bean epicotyls independently of the direction of stimuli

    NASA Astrophysics Data System (ADS)

    Soga, K.; Wakabayashi, K.; Kamisaka, S.; Hoson, T.

    We examined the effects of basipetal, horizontal, and acropetal hypergravity stimulation on growth and cell wall properties of azuki bean seedlings. Horizontal and acropetal hypergravity inhibited elongation growth of epicotyls by decreasing the cell wall extensibility, as did basipetal hypergravity. Hypergravity stimulation increased the thickness of cell walls and suppressed xyloglucan breakdown regardless of direction. All hypergravity treatments increased the pH in the apoplastic fluid, which is involved in the processes of the suppression of xyloglucan breakdown. Gadolinium and lanthanum, both blockers of mechanoreceptors, nullified the growth-inhibiting effects of hypergravity. These results show that growth inhibition by hypergravity is independent of its direction in azuki bean epicotyls. The findings also suggest that mechanoreceptors on the plasma membrane perceive the gravity signal independently of its direction, and affect growth of azuki bean epicotyls.

  20. Ethylene production throughout growth and development of plants

    NASA Technical Reports Server (NTRS)

    Wheeler, Raymond M.; Peterson, Barbara V.; Stutte, Gary W.

    2004-01-01

    Ethylene production by 10 or 20 m2 stands of wheat, soybean, lettuce, potato, and tomato was monitored throughout growth and development in an atmospherically closed plant chamber. Chamber ethylene levels varied among species and rose during periods of canopy expansion and rapid growth for all species. Following this, ethylene levels either declined during seed fill and maturation for wheat and soybean, or remained relatively constant for potato and tomato (during flowering and early fruit development). Lettuce plants were harvested during rapid growth and peak ethylene production. Chamber ethylene levels increased rapidly during tomato ripening, reaching concentrations about 10 times that measured during vegetative growth. The highest ethylene production rates during vegetative growth ranged from 1.6 to 2.5 nmol m-2 d-1 during rapid growth of lettuce and wheat stands, or about 0.3 to 0.5 nmol g-1 fresh weight per hour. Estimates of stand ethylene production during tomato ripening showed that rates reached 43 nmol m-2 d-1 in one study and 93 nmol m-2 d-1 in a second study with higher lighting, or about 50x that of the rate during vegetative growth of tomato. In a related test with potato, the photoperiod was extended from 12 to 24 hours (continuous light) at 58 days after planting (to increase tuber yield), but this change in the environment caused a sharp increase in ethylene production from the basal rate of 0.4 to 6.2 nmol m-2 d-1. Following this, the photoperiod was changed back to 12 h at 61 days and ethylene levels decreased. The results suggest three separate categories of ethylene production were observed with whole stands of plants: 1) production during rapid vegetative growth, 2) production during climacteric fruit ripening, and 3) production from environmental stress.

  1. Magnetic fluids effect upon growth processes in plants

    NASA Astrophysics Data System (ADS)

    Sala, F.

    1999-07-01

    The metabolic processes of plants growth and development take place according to some organic rules which are specific to their genetic potential. These processes may exhibit modifications of intensity, rhythm, sense, under the influence of the environmental conditions of agricultural systems, through certain factors and bioregulators artificially introduced by man. The results of some investigations regarding effects of biocompatible magnetic fluids (LMW 100 G) on the vegetal organism's (growth, development, fructifying, the level and quality of the yield precocity) are presented.

  2. Gibberellin Is Involved in Inhibition of Cucumber Growth and Nitrogen Uptake at Suboptimal Root-Zone Temperatures.

    PubMed

    Bai, Longqiang; Deng, Huihui; Zhang, Xiaocui; Yu, Xianchang; Li, Yansu

    2016-01-01

    Suboptimal temperature stress often causes heavy yield losses of vegetables by suppressing plant growth during winter and early spring. Gibberellin acid (GA) has been reported to be involved in plant growth and acquisition of mineral nutrients. However, no studies have evaluated the role of GA in the regulation of growth and nutrient acquisition by vegetables under conditions of suboptimal temperatures in greenhouse. Here, we investigated the roles of GA in the regulation of growth and nitrate acquisition of cucumber (Cucumis sativus L.) plants under conditions of short-term suboptimal root-zone temperatures (Tr). Exposure of cucumber seedlings to a Tr of 16°C led to a significant reduction in root growth, and this inhibitory effect was reversed by exogenous application of GA. Expression patterns of several genes encoding key enzymes in GA metabolism were altered by suboptimal Tr treatment, and endogenous GA concentrations in cucumber roots were significantly reduced by exposure of cucumber plants to 16°C Tr, suggesting that inhibition of root growth by suboptimal Tr may result from disruption of endogenous GA homeostasis. To further explore the mechanism underlying the GA-dependent cucumber growth under suboptimal Tr, we studied the effect of suboptimal Tr and GA on nitrate uptake, and found that exposure of cucumber seedlings to 16°C Tr led to a significant reduction in nitrate uptake rate, and exogenous application GA can alleviate the down-regulation by up regulating the expression of genes associated with nitrate uptake. Finally, we demonstrated that N accumulation in cucumber seedlings under suboptimal Tr conditions was improved by exogenous application of GA due probably to both enhanced root growth and nitrate absorption activity. These results indicate that a reduction in endogenous GA concentrations in roots due to down-regulation of GA biosynthesis at transcriptional level may be a key event to underpin the suboptimal Tr-induced inhibition of root

  3. Gibberellin Is Involved in Inhibition of Cucumber Growth and Nitrogen Uptake at Suboptimal Root-Zone Temperatures

    PubMed Central

    Zhang, Xiaocui; Yu, Xianchang

    2016-01-01

    Suboptimal temperature stress often causes heavy yield losses of vegetables by suppressing plant growth during winter and early spring. Gibberellin acid (GA) has been reported to be involved in plant growth and acquisition of mineral nutrients. However, no studies have evaluated the role of GA in the regulation of growth and nutrient acquisition by vegetables under conditions of suboptimal temperatures in greenhouse. Here, we investigated the roles of GA in the regulation of growth and nitrate acquisition of cucumber (Cucumis sativus L.) plants under conditions of short-term suboptimal root-zone temperatures (Tr). Exposure of cucumber seedlings to a Tr of 16°C led to a significant reduction in root growth, and this inhibitory effect was reversed by exogenous application of GA. Expression patterns of several genes encoding key enzymes in GA metabolism were altered by suboptimal Tr treatment, and endogenous GA concentrations in cucumber roots were significantly reduced by exposure of cucumber plants to 16°C Tr, suggesting that inhibition of root growth by suboptimal Tr may result from disruption of endogenous GA homeostasis. To further explore the mechanism underlying the GA-dependent cucumber growth under suboptimal Tr, we studied the effect of suboptimal Tr and GA on nitrate uptake, and found that exposure of cucumber seedlings to 16°C Tr led to a significant reduction in nitrate uptake rate, and exogenous application GA can alleviate the down-regulation by up regulating the expression of genes associated with nitrate uptake. Finally, we demonstrated that N accumulation in cucumber seedlings under suboptimal Tr conditions was improved by exogenous application of GA due probably to both enhanced root growth and nitrate absorption activity. These results indicate that a reduction in endogenous GA concentrations in roots due to down-regulation of GA biosynthesis at transcriptional level may be a key event to underpin the suboptimal Tr-induced inhibition of root

  4. Gibberellin Is Involved in Inhibition of Cucumber Growth and Nitrogen Uptake at Suboptimal Root-Zone Temperatures.

    PubMed

    Bai, Longqiang; Deng, Huihui; Zhang, Xiaocui; Yu, Xianchang; Li, Yansu

    2016-01-01

    Suboptimal temperature stress often causes heavy yield losses of vegetables by suppressing plant growth during winter and early spring. Gibberellin acid (GA) has been reported to be involved in plant growth and acquisition of mineral nutrients. However, no studies have evaluated the role of GA in the regulation of growth and nutrient acquisition by vegetables under conditions of suboptimal temperatures in greenhouse. Here, we investigated the roles of GA in the regulation of growth and nitrate acquisition of cucumber (Cucumis sativus L.) plants under conditions of short-term suboptimal root-zone temperatures (Tr). Exposure of cucumber seedlings to a Tr of 16°C led to a significant reduction in root growth, and this inhibitory effect was reversed by exogenous application of GA. Expression patterns of several genes encoding key enzymes in GA metabolism were altered by suboptimal Tr treatment, and endogenous GA concentrations in cucumber roots were significantly reduced by exposure of cucumber plants to 16°C Tr, suggesting that inhibition of root growth by suboptimal Tr may result from disruption of endogenous GA homeostasis. To further explore the mechanism underlying the GA-dependent cucumber growth under suboptimal Tr, we studied the effect of suboptimal Tr and GA on nitrate uptake, and found that exposure of cucumber seedlings to 16°C Tr led to a significant reduction in nitrate uptake rate, and exogenous application GA can alleviate the down-regulation by up regulating the expression of genes associated with nitrate uptake. Finally, we demonstrated that N accumulation in cucumber seedlings under suboptimal Tr conditions was improved by exogenous application of GA due probably to both enhanced root growth and nitrate absorption activity. These results indicate that a reduction in endogenous GA concentrations in roots due to down-regulation of GA biosynthesis at transcriptional level may be a key event to underpin the suboptimal Tr-induced inhibition of root

  5. Two genetically separable phases of growth inhibition induced by blue light in Arabidopsis seedlings

    NASA Technical Reports Server (NTRS)

    Parks, B. M.; Cho, M. H.; Spalding, E. P.; Evans, M. L. (Principal Investigator)

    1998-01-01

    High fluence-rate blue light (BL) rapidly inhibits hypocotyl growth in Arabidopsis, as in other species, after a lag time of 30 s. This growth inhibition is always preceded by the activation of anion channels. The membrane depolarization that results from the activation of anion channels by BL was only 30% of the wild-type magnitude in hy4, a mutant lacking the HY4 BL receptor. High-resolution measurements of growth made with a computer-linked displacement transducer or digitized images revealed that BL caused a rapid inhibition of growth in wild-type and hy4 seedlings. This inhibition persisted in wild-type seedlings during more than 40 h of continuous BL. By contrast, hy4 escaped from the initial inhibition after approximately 1 h of BL and grew faster than wild type for approximately 30 h. Wild-type seedlings treated with 5-nitro-2-(3-phenylpropylamino)-benzoic acid, a potent blocker of the BL-activated anion channel, displayed rapid growth inhibition, but, similar to hy4, these seedlings escaped from inhibition after approximately 1 h of BL and phenocopied the mutant for at least 2.5 h. The effects of 5-nitro-2-(3-phenylpropylamino)-benzoic acid and the HY4 mutation were not additive. Taken together, the results indicate that BL acts through HY4 to activate anion channels at the plasma membrane, causing growth inhibition that begins after approximately 1 h. Neither HY4 nor anion channels appear to participate greatly in the initial phase of inhibition.

  6. Selenium-enriched polysaccharides from Pyracantha fortuneana (Se-PFPs) inhibit the growth and invasive potential of ovarian cancer cells through inhibiting β-catenin signaling

    PubMed Central

    Wang, Changdong; Sheng, Deqiao; Li, Zhihong; Huang, Debin; Yuan, Chengfu

    2016-01-01

    Polysaccharides from medicinal plants exert antitumor activity in many cancers. Our previous study demonstrated that polysaccharides extracted from the selenium-enriched Pyracantha fortuneana (Se-PFPs) showed antiproliferative effect in breast cancer cell line. This study aimed to investigate the antitumor effect of Se-PFPs in ovarian cancer cells in vitro and in vivo. Se-PFPs could decrease cell viability, induce apoptosis, and inhibit migratory and invasive potentials in HEY and SKOV3 cells. These findings are supported by reduced expression of cyclin D1, Bcl-2 and MMP-9, enhanced cleavage of PARP and caspase-3, elevated activity of caspase-3 and caspase-9, and EMT (epithelial to mesenchymal transition) inhibition (elevated expression of E-cadherin and cytokeratin 19, and reduced expression of N-cadherin, vimentin, ZEB1 and ZEB2). Moreover, Se-PFPs inhibited xenografted tumor growth through inhibiting cell proliferation and inducing cell apoptosis. More importantly, Se-PFPs significantly reduced cytoplasmic β-catenin particularly nuclear β-catenin expression but increased β-catenin phosphorylation in a GSK-3β-dependent mechanism. Furthermore, β-catenin knockdown exerted similar effects on cell proliferation and invasion as seen in Se-PFPs-treated cells, while β-catenin overexpression neutralized the inhibitory effects of Se-PFPs on cell proliferation and invasion. Take together,Se-PFPs exert antitumor activity through inhibiting cell proliferation, migration, invasion and EMT, and inducing cell apoptosis. These effects are achieved by the inhibition of β-catenin signaling. Thus Se-PFPs can be used as potential therapeutic agents in the prevention and treatment of ovarian cancer. PMID:27058760

  7. Involvement of plant growth substances in the alteration of leaf gas exchange of flooded tomato plants.

    PubMed

    Bradford, K J

    1983-10-01

    Ethylene, abscisic acid, and cytokinins were tested for their ability to either induce or prevent the changes which occur in gas exchange characteristics of tomato (Lycopersicon esculentum Mill. cv. Rheinlands Ruhm) leaves during short-term soil flooding. Ethylene, which increases in the shoots of flooded plants, had no effect on stomatal conductance or photosynthetic capacity of drained plants. Abscisic acid, which also accumulates in the shoots of flooded plants, could reproduce the stomatal behavior of flooded plants when sprayed on the leaves of drained plants. However, photosynthetic capacity of drained plants was unaffected by abscisic acid sprays. Cytokinin export from the roots to the shoots declines in flooded plants. Spray applications of benzyladenine increased stomatal conductance in both flooded and drained plants. In addition, the decline in photosynthetic capacity during flooding was largely prevented by supplementary cytokinin applications. The possible involvement of these growth substances in modifying leaf gas exchange during flooding is discussed.

  8. Ivermectin inhibits growth of Chlamydia trachomatis in epithelial cells.

    PubMed

    Pettengill, Matthew A; Lam, Verissa W; Ollawa, Ikechukwu; Marques-da-Silva, Camila; Ojcius, David M

    2012-01-01

    Ivermectin is currently approved for treatment of both clinical and veterinary infections by nematodes, including Onchocerca cervicalis in horses and Onchocerca volvulus in humans. However, ivermectin has never been shown to be effective against bacterial pathogens. Here we show that ivermectin also inhibits infection of epithelial cells by the bacterial pathogen, Chlamydia trachomatis, at doses that could be envisioned clinically for sexually-transmitted or ocular infections by Chlamydia. PMID:23119027

  9. Plant growth chamber based on space proven controlled environment technology

    NASA Astrophysics Data System (ADS)

    Ignatius, Ronald W.; Ignatius, Matt H.; Imberti, Henry J.

    1997-01-01

    Quantum Devices, Inc., in conjunction with Percival Scientific, Inc., and the Wisconsin Center for Space Automation and Robotics (WCSAR) have developed a controlled environment plant growth chamber for terrestrial agricultural and scientific applications. This chamber incorporates controlled environment technology used in the WCSAR ASTROCULTURE™ flight unit for conducting plant research on the Space Shuttle. The new chamber, termed CERES 2010, features air humidity, temperature, and carbon dioxide control, an atmospheric contaminant removal unit, an LED lighting system, and a water and nutrient delivery system. The advanced environment control technology used in this chamber will increase the reliability and repeatability of environmental physiology data derived from plant experiments conducted in this chamber.

  10. Alum sludge land application and its effect on plant growth

    SciTech Connect

    Lucas, J.B. ); Dillaha, T.A.; Reneau, R.B.; Novak, J.T.; Knocke, W.R. )

    1994-11-01

    These investigators conducted three greenhouse experiments to determine the impact of alum sludge from the Harwood's Mill water treatment plant, newport News, Va., on the growth and chemical composition of fescue grass. Fescue yields decreased with increased sludge addition, a trend that was attributed to reductions in plant-available phosphorus (P) at higher loadings. Supplemental P fertilization corrected this deficiency. Lime addition did not affect yield. The presence of manganese and copper in the sludge increased metal uptake by the plants but did not affect yield.

  11. Essential Oils from Ugandan Aromatic Medicinal Plants: Chemical Composition and Growth Inhibitory Effects on Oral Pathogens.

    PubMed

    Ocheng, Francis; Bwanga, Freddie; Joloba, Moses; Softrata, Abier; Azeem, Muhammad; Pütsep, Katrin; Borg-Karlson, Anna-Karin; Obua, Celestino; Gustafsson, Anders

    2015-01-01

    The study assessed the growth inhibitory effects of essential oils extracted from ten Ugandan medicinal plants (Bidens pilosa, Helichrysum odoratissimum, Vernonia amygdalina, Hoslundia opposita, Ocimum gratissimum, Cymbopogon citratus, Cymbopogon nardus, Teclea nobilis, Zanthoxylum chalybeum, and Lantana trifolia) used traditionally in the management of oral diseases against oral pathogens. Chemical compositions of the oils were explored by GC-MS. Inhibitory effects of the oils were assessed on periodontopathic Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans and cariogenic Streptococcus mutans and Lactobacillus acidophilus using broth dilution methods at concentrations of 1%, 0.1%, and 0.01%. The most sensitive organism was A. actinomycetemcomitans. Its growth was markedly inhibited by six of the oils at all the concentrations tested. Essential oil from C. nardus exhibited the highest activity with complete growth inhibition of A. actinomycetemcomitans and P. gingivalis at all the three concentrations tested, the major constituents in the oil being mainly oxygenated sesquiterpenes. Most of the oils exhibited limited effects on L. acidophilus. We conclude that essential oils from the studied plants show marked growth inhibitory effects on periodontopathic A. actinomycetemcomitans and P. gingivalis, moderate effects on cariogenic S. mutans, and the least effect on L. acidophilus. The present study constitutes a basis for further investigations and development of certain oils into alternative antiplaque agents. PMID:26170872

  12. All about Plant Structure & Growth. Plant Life for Children[TM]. Schlessinger Science Library. [Videotape].

    ERIC Educational Resources Information Center

    2000

    How does a tiny seed sprout and grow into a towering tree? Join the kids from M.A.P.L.E as they learn about some of the incredible transformations that a plant goes through during its lifetime. In All About Plant Structure & Growth, uncover the secrets of roots, stems and leaves - structures that are vital to a plant's role as an energy producer.…

  13. Inhibition of the growth of Alexandrium tamarense by algicidal substances in Chinese fir (Cunninghamia lanceolata).

    PubMed

    Yang, Wei-Dong; Liu, Jie-Sheng; Li, Hong-Ye; Zhang, Xin-Lian; Qi, Yu-Zao

    2009-10-01

    The wood sawdust from Chinese fir (Cunninghamia lanceolata) exhibited stronger inhibition on the growth of Alexandrium tamarense than those from alder (Alnus cremastogyne), pine (Pinus massoniana), birch (Betula alnoides) and sapele (Entandrophragma cylindricum). The water extract, acetone-water extract and essential oil from fir sawdust were all shown to inhibit the growth of A. tamarense. The inhibition of fir essential oil was the strongest among all the above wood sources while the half effective concentration was only 0.65 mg/L. These results suggested that the fir essential oil may play an important role in the algicidal effect of Chinese fir. PMID:19634014

  14. β-Pinene inhibited germination and early growth involves membrane peroxidation.

    PubMed

    Chowhan, Nadia; Singh, Harminder Pal; Batish, Daizy R; Kaur, Shalinder; Ahuja, Nitina; Kohli, Ravinder K

    2013-06-01

    β-Pinene, an oxygenated monoterpene, is abundantly found in the environment and widely occurring in plants as a constituent of essential oils. We investigated the phytotoxicity of β-pinene against two grassy (Phalaris minor, Echinochloa crus-galli) and one broad-leaved (Cassia occidentalis) weeds in terms of germination and root and shoot growth. β-Pinene (0.02-0.80 mg/ml) inhibited the germination, root length, and shoot length of test weeds in a dose-response manner. The inhibitory effect of β-pinene was greater in grassy weeds and on root growth than on shoot growth. β-Pinene (0.04-0.80 mg/ml) reduced the root length in P. minor, E. crus-galli, and C. occidentalis over that in the control by 58-60, 44-92, and 26-85 %, respectively. In contrast, shoot length was reduced over the control by 45-97 % in P. minor, 48-78 % in E. crus-galli, and 11-75 % in C. occidentalis at similar concentrations. Further, we examined the impact of β-pinene on membrane integrity in P. minor as one of the possible mechanisms of action. Membrane integrity was evaluated in terms of lipid peroxidation, conjugated diene content, electrolyte leakage, and the activity of lipoxygenases (LOX). β-Pinene (≥0.04 mg/ml) enhanced electrolyte leakage by 23-80 %, malondialdehyde content by 15-67 %, hydrogen peroxide content by 9-39 %, and lipoxygenases activity by 38-383 % over that in the control. It indicated membrane peroxidation and loss of membrane integrity that could be the primary target of β-pinene. Even the enhanced (9-62 %) activity of protecting enzymes, peroxidases (POX), was not able to protect the membranes from β-pinene (0.04-0.20 mg/ml)-induced toxicity. In conclusion, our results show that β-pinene inhibits root growth of the tested weed species through disruption of membrane integrity as indicated by enhanced peroxidation, electrolyte leakage, and LOX activity despite the upregulation of POX activity.

  15. Growth Chambers on the International Space Station for Large Plants

    NASA Technical Reports Server (NTRS)

    Massa, Gioia D.; Wheeler, Raymond M.; Morrow, Robert C.; Levine, Howard G.

    2016-01-01

    The International Space Station (ISS) now has platforms for conducting research on horticultural plant species under LED (Light Emitting Diodes) lighting, and those capabilities continue to expand. The Veggie vegetable production system was deployed to the ISS as an applied research platform for food production in space. Veggie is capable of growing a wide array of horticultural crops. It was designed for low power usage, low launch mass and stowage volume, and minimal crew time requirements. The Veggie flight hardware consists of a light cap containing red (630 nanometers), blue, (455 nanometers) and green (530 nanometers) LEDs. Interfacing with the light cap is an extendable bellowsbaseplate for enclosing the plant canopy. A second large plant growth chamber, the Advanced Plant Habitat (APH), is will fly to the ISS in 2017. APH will be a fully controllable environment for high-quality plant physiological research. APH will control light (quality, level, and timing), temperature, CO2, relative humidity, and irrigation, while scrubbing any cabin or plant-derived ethylene and other volatile organic compounds. Additional capabilities include sensing of leaf temperature and root zone moisture, root zone temperature, and oxygen concentration. The light cap will have red (630 nm), blue (450 nm), green (525 nm), far red (730 nm) and broad spectrum white LEDs (4100K). There will be several internal cameras (visible and IR) to monitor and record plant growth and operations. Veggie and APH are available for research proposals.

  16. Growth Chambers on the International Space Station for Large Plants

    NASA Technical Reports Server (NTRS)

    Massa, G. D.; Wheeler, R. M.; Morrow, R. C.; Levine, H. G.

    2016-01-01

    The International Space Station (ISS) now has platforms for conducting research on horticultural plant species under LED lighting, and those capabilities continue to expand. The 'Veggie' vegetable production system was deployed to the ISS as an applied research platform for food production in space. Veggie is capable of growing a wide array of horticultural crops. It was designed for low power usage, low launch mass and stowage volume, and minimal crew time requirements. The Veggie flight hardware consists of a light cap containing red (630 nm), blue, (455 nm) and green (530 nm) LEDs. Interfacing with the light cap is an extendable bellows/baseplate for enclosing the plant canopy. A second large plant growth chamber, the Advanced Plant Habitat (APH), is will fly to the ISS in 2017. APH will be a fully controllable environment for high-quality plant physiological research. APH will control light (quality, level, and timing), temperature, CO2, relative humidity, and irrigation, while scrubbing any cabin or plant-derived ethylene and other volatile organic compounds. Additional capabilities include sensing of leaf temperature and root zone moisture, root zone temperature, and oxygen concentration. The light cap will have red (630 nm), blue (450 nm), green (525 nm), far red (730 nm) and broad spectrum white LEDs (4100K). There will be several internal cameras (visible and IR) to monitor and record plant growth and operations. Veggie and APH are available for research proposals.

  17. Effects of Engineered Nanomaterials on Plants Growth: An Overview

    PubMed Central

    Bagheri, Samira; Muhd Julkapli, Nurhidayatullaili; Juraimi, Abdul Shukor; Hashemi, Farahnaz Sadat Golestan

    2014-01-01

    Rapid development and wide applications of nanotechnology brought about a significant increment on the number of engineered nanomaterials (ENs) inevitably entering our living system. Plants comprise of a very important living component of the terrestrial ecosystem. Studies on the influence of engineered nanomaterials (carbon and metal/metal oxides based) on plant growth indicated that in the excess content, engineered nanomaterials influences seed germination. It assessed the shoot-to-root ratio and the growth of the seedlings. From the toxicological studies to date, certain types of engineered nanomaterials can be toxic once they are not bound to a substrate or if they are freely circulating in living systems. It is assumed that the different types of engineered nanomaterials affect the different routes, behavior, and the capability of the plants. Furthermore, different, or even opposing conclusions, have been drawn from most studies on the interactions between engineered nanomaterials with plants. Therefore, this paper comprehensively reviews the studies on the different types of engineered nanomaterials and their interactions with different plant species, including the phytotoxicity, uptakes, and translocation of engineered nanomaterials by the plant at the whole plant and cellular level. PMID:25202734

  18. Effects of engineered nanomaterials on plants growth: an overview.

    PubMed

    Aslani, Farzad; Bagheri, Samira; Muhd Julkapli, Nurhidayatullaili; Juraimi, Abdul Shukor; Hashemi, Farahnaz Sadat Golestan; Baghdadi, Ali

    2014-01-01

    Rapid development and wide applications of nanotechnology brought about a significant increment on the number of engineered nanomaterials (ENs) inevitably entering our living system. Plants comprise of a very important living component of the terrestrial ecosystem. Studies on the influence of engineered nanomaterials (carbon and metal/metal oxides based) on plant growth indicated that in the excess content, engineered nanomaterials influences seed germination. It assessed the shoot-to-root ratio and the growth of the seedlings. From the toxicological studies to date, certain types of engineered nanomaterials can be toxic once they are not bound to a substrate or if they are freely circulating in living systems. It is assumed that the different types of engineered nanomaterials affect the different routes, behavior, and the capability of the plants. Furthermore, different, or even opposing conclusions, have been drawn from most studies on the interactions between engineered nanomaterials with plants. Therefore, this paper comprehensively reviews the studies on the different types of engineered nanomaterials and their interactions with different plant species, including the phytotoxicity, uptakes, and translocation of engineered nanomaterials by the plant at the whole plant and cellular level. PMID:25202734

  19. Mechanisms of inhibition of viral replication in plants

    SciTech Connect

    Not Available

    1990-01-01

    We have made a number of interesting observations of importance to the fields of virology and plant molecular biology. Topics include the genome of cucumber mosaic virus (CMV), recombination of the CMV genome, transgenic plants and viral movement genes, mapping resistance breakage sequences in the tomato mosaic virus (TMV) genome, and mapping pathogeneticity domains and viral RNA heterogeneity. 1 fig., 1 tab.

  20. A bacterial tyrosine phosphatase inhibits plant pattern recognition receptor activation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Perception of pathogen-associated molecular patterns (PAMPs) by surface-localised pattern-recognition receptors (PRRs) is a key component of plant innate immunity. Most known plant PRRs are receptor kinases and initiation of PAMP-triggered immunity (PTI) signalling requires phosphorylation of the PR...

  1. Connecting growth and defense: the emerging roles of brassinosteroids and gibberellins in plant innate immunity.

    PubMed

    De Bruyne, Lieselotte; Höfte, Monica; De Vleesschauwer, David

    2014-06-01

    Brassinosteroids (BRs) and gibberellins (GAs) are two groups of phytohormones that regulate many common developmental processes throughout the plant life cycle. Fueled by large-scale 'omics' technologies and the burgeoning field of plant computational biology, the past few years have witnessed paradigm-shifting advances in our understanding of how BRs and GA are perceived and their signals transduced. Accumulating evidence also implicates BR and GA in the coordination and integration of plant immune responses. Similarly to other growth regulators, BR and GA play ambiguous roles in molding pathological outcomes, the effects of which may depend not only on the pathogen's lifestyle and infection strategy, but also on specialized features of each interaction. Analysis of the underpinning molecular mechanisms points to a crucial role of GA-inhibiting DELLA proteins and the BR-regulated transcription factor BZR1. Acting at the interface of developmental and defense signaling, these proteins likely serve as central hubs for pathway crosstalk and signal integration, allowing appropriate modulation of plant growth and defense in response to various stimuli. In this review, we outline the latest discoveries dealing with BR and GA modulation of plant innate immunity and highlight interactions between BR and GA signaling, plant defense, and microbial virulence.

  2. Inhibition of Escherichia coli growth and diaminopimelic acid epimerase by 3-chlorodiaminopimelic acid.

    PubMed Central

    Baumann, R J; Bohme, E H; Wiseman, J S; Vaal, M; Nichols, J S

    1988-01-01

    The diaminopimelic acid (DAP) analog, 3-chloro-DAP, was synthesized and tested as the racemic acid for antibacterial activity and for inhibition of DAP epimerase. 3-Chloro-DAP was a potent inhibitor of DAP epimerase purified from Escherichia coli (Ki = 200 nM), and it is argued that 3-chloro-DAP is converted to a tight-binding transition state analog at the active site of this enzyme. Furthermore, 3-chloro-DAP inhibited growth of two E. coli mutants. In one of the mutants known for supersusceptibility to beta-lactams, inhibition was not seen until the mid-log phase of growth, while in the other mutant, a DAP auxotroph, inhibition occurred much earlier. Growth inhibition was reversed by DAP in both strains. In the auxotroph, the reversal was specific for meso-DAP, indicating that DAP epimerase was the target for 3-chloro-DAP. Thus we suggest a novel mechanism of bacterial growth inhibition which depends on DAP epimerase inhibition by a DAP analog. PMID:3056252

  3. Phosphatase and tensin homolog reconstruction and vascular endothelial growth factor knockdown synergistically inhibit the growth of glioblastoma.

    PubMed

    Chen, Hongbo; Shen, Xiaomeng; Guo, Caiping; Zhu, Huijun; Zhou, Lanzhen; Zhu, Yongqiang; Wang, Huixia; Zheng, Yi; Huang, Laiqiang

    2010-12-01

    Glioblastoma (GBM) is a highly malignant tumor with poor prognosis. Two hallmarks of this disease are a high expression of vascular endothelial growth factor (VEGF) and a depletion of the phosphatase and tensin homolog (PTEN). In the present study, combined gene therapy using wild-type PTEN reconstruction and VEGF siRNA was examined for its effectiveness in inhibiting tumor growth and tumorigenicity of PTEN-null GBM cells. In U251 GBM cells, PTEN restoration reduced proliferation, arrested the cell cycle at G0/G1 stage, and promoted apoptosis via inhibition of PIK/AKT signaling pathway. Unexpectedly, anchorage-dependent and -independent colony formation ability and the capacity for wound-healing migration of U251 cells with stable expression of VEGF siRNA were significantly inhibited, suggesting that VEGF also appeared to function as an autocrine growth factor in addition to its well-known pro-angiogenic paracrine function. Further, a combined treatment of PTEN restoration and VEGF siRNA had the best tumor suppression effect. In a xenograft study in null mice, both the restoration of PTEN and the expression of VEGF siRNA could significantly inhibit the growth of U251 GBMs, whereas tumor growth was entirely suppressed by a combination of the two treatments. Therefore, the combination of PTEN expression and VEGF knockdown represents an effective gene therapy strategy for malignant gliomas.

  4. THE INFLUENCE OF MAGNETIC FIELDS ON INHIBITION OF MCF-7 CELL GROWTH BY TAMOXIFEN

    EPA Science Inventory

    THE INFLUENCE OF MAGNETIC FIELDS ON INHIBITION OF MCF-7 CELL GROWTH BY TAMOXIFEN.
    Harland and Liburdy (1) reported that 1.2-uT, 60-Hz magnetic fields could significantly block the inhibitory action of pharmacological levels of tamoxifen (10-7 M) on the growth of MCF-7 human br...

  5. Enhancement or inhibition of tumor growth by interferon: dependence on treatment protocol.

    PubMed

    Murasko, D M; Fresa, K; Mark, R

    1983-12-15

    MSC cells are tumor cells originally induced in BALB/c mice by Moloney sarcoma virus. In these studies we demonstrated that, although these tumor cells are sensitive in vitro both to lysis by NK or NK-like cells and to the growth-inhibitory effect of murine L-cell interferon (IFN), the growth of the tumor in vivo could be either inhibited or enhanced by IFN. The outcome of in vivo IFN treatment was dependent on the timing and route of IFN administration relative to tumor challenge. IFN given systematically at the same time as tumor challenge resulted in enhancement of primary tumor formation, rate of tumor growth and subsequent progressive tumor growth. In contrast, IFN administered at the site of tumor inoculation on days 1-3 after tumor challenge inhibited tumor formation and growth. Histopathology of tissue sections obtained from the site of tumor challenge confirmed these results. Similar studies performed in mice given 450 rads of X-irradiation showed that IFN could still inhibit tumor growth when administered at the site of tumor inoculation on days 1-3 after tumor challenge. IFN administered simultaneously with tumor challenge, however, did not enhance tumor growth in irradiated mice. These results are consistent with the interpretation that 1) inhibition of MSC-induced tumor growth by IFN has a radioresistant component and 2) the enhancement of MSC-induced tumor formation by IFN is dependent on interaction with a radiosensitive population of cells, possibly lymphoid cells. PMID:6360916

  6. Plant Growth Promotion Activity of Keratinolytic Fungi Growing on a Recalcitrant Waste Known as “Hair Waste”

    PubMed Central

    Cavello, Ivana A.; Crespo, Juan M.; García, Sabrina S.; Zapiola, José M.; Luna, María F.; Cavalitto, Sebastián F.

    2015-01-01

    Purpureocillium lilacinum (Thom) Samsom is one of the most studied fungi in the control of plant parasitic nematodes. However, there is not specific information on its ability to inhibit some pathogenic bacteria, fungi, or yeast. This work reports the production of several antifungal hydrolytic enzymes by a strain of P. lilacinum when it is grown in a medium containing hair waste. The growth of several plant-pathogenic fungi, Alternaria alternata, Aspergillus niger, and Fusarium culmorum, was considerably affected by the presence of P. lilacinum's supernatant. Besides antifungal activity, P. lilacinum demonstrates the capability to produce indoleacetic acid and ammonia during time cultivation on hair waste medium. Plant growth-promoting activity by cell-free supernatant was evidenced through the increase of the percentage of tomato seed germination from 71 to 85% after 48 hours. A 21-day plant growth assay using tomato plants indicates that crude supernatant promotes the growth of the plants similar to a reference fertilizer (p > 0.05). These results suggest that both strain and the supernatant may have potential to be considered as a potent biocontrol agent with multiple plant growth-promoting properties. To our knowledge, this is the first report on the antifungal, IAA production and tomato growth enhancing compounds produced by P. lilacinum LPSC #876. PMID:26697226

  7. Rhizobacterial Strain Bacillus megaterium BOFC15 Induces Cellular Polyamine Changes that Improve Plant Growth and Drought Resistance

    PubMed Central

    Zhou, Cheng; Ma, Zhongyou; Zhu, Lin; Xiao, Xin; Xie, Yue; Zhu, Jian; Wang, Jianfei

    2016-01-01

    Plant-growth-promoting rhizobacteria can improve plant growth, development, and stress adaptation. However, the underlying mechanisms are still largely unclear. We investigated the effects of Bacillus megaterium BOFC15 on Arabidopsis plants. BOFC15 produced and secreted spermidine (Spd), a type of polyamine (PA) that plays an important role in plant growth. Moreover, BOFC15 induced changes in the cellular PAs of plants that promoted an increase of free Spd and spermine levels. However, these effects were remarkably abolished by the addition of dicyclohexylamine (DCHA), a Spd biosynthetic inhibitor. Additionally, the inoculation with BOFC15 remarkably increased plant biomass, improved root system architecture, and augmented photosynthetic capacity. Inoculated plants also displayed stronger ability to tolerate drought stress than non-inoculated (control) plants. Abscisic acid (ABA) content was notably higher in the inoculated plants than in the control plants under drought stress and polyethylene glycol (PEG)-induced stress conditions. However, the BOFC15-induced ABA synthesis was markedly inhibited by DCHA. Thus, microbial Spd participated in the modulation of the ABA levels. The Spd-producing BOFC15 improved plant drought tolerance, which was associated with altered cellular ABA levels and activated adaptive responses. PMID:27338359

  8. Rhizobacterial Strain Bacillus megaterium BOFC15 Induces Cellular Polyamine Changes that Improve Plant Growth and Drought Resistance.

    PubMed

    Zhou, Cheng; Ma, Zhongyou; Zhu, Lin; Xiao, Xin; Xie, Yue; Zhu, Jian; Wang, Jianfei

    2016-01-01

    Plant-growth-promoting rhizobacteria can improve plant growth, development, and stress adaptation. However, the underlying mechanisms are still largely unclear. We investigated the effects of Bacillus megaterium BOFC15 on Arabidopsis plants. BOFC15 produced and secreted spermidine (Spd), a type of polyamine (PA) that plays an important role in plant growth. Moreover, BOFC15 induced changes in the cellular PAs of plants that promoted an increase of free Spd and spermine levels. However, these effects were remarkably abolished by the addition of dicyclohexylamine (DCHA), a Spd biosynthetic inhibitor. Additionally, the inoculation with BOFC15 remarkably increased plant biomass, improved root system architecture, and augmented photosynthetic capacity. Inoculated plants also displayed stronger ability to tolerate drought stress than non-inoculated (control) plants. Abscisic acid (ABA) content was notably higher in the inoculated plants than in the control plants under drought stress and polyethylene glycol (PEG)-induced stress conditions. However, the BOFC15-induced ABA synthesis was markedly inhibited by DCHA. Thus, microbial Spd participated in the modulation of the ABA levels. The Spd-producing BOFC15 improved plant drought tolerance, which was associated with altered cellular ABA levels and activated adaptive responses. PMID:27338359

  9. Telerobotic Tending of Space Based Plant Growth Chamber

    NASA Technical Reports Server (NTRS)

    Backes, P. G.; Long, M. K.; Das, H.

    1994-01-01

    The kinematic design of a telerobotic mechanism for tending a plant growth space science experiment chamber is described. Ground based control of tending mechanisms internal to space science experiments will allow ground based principal investigators to interact directly with their space science experiments.

  10. Plant Classification by Growth Form for Field Use.

    ERIC Educational Resources Information Center

    Kemp, David M.

    1982-01-01

    A simple classification system for terrestrial plants is presented. The method is based on growth forms and avoids the need for identification to genus or species, although students could be encouraged to follow the work through to this level if appropriate. (Author/JN)

  11. Influence of Polymers on the Crystal Growth Rate of Felodipine: Correlating Adsorbed Polymer Surface Coverage to Solution Crystal Growth Inhibition.

    PubMed

    Schram, Caitlin J; Taylor, Lynne S; Beaudoin, Stephen P

    2015-10-20

    The bioavailability of orally administered drugs that exhibit poor aqueous solubility can be enhanced with the use of supersaturating dosage forms. Stabilization of these forms by preventing or inhibiting crystallization in solution is an important area of study. Polymers can be used to stabilize supersaturated systems; however, the properties that impact their effectiveness as crystal growth rate inhibitors are not yet fully understood. In this study, the impact of various polymers on the crystal growth rate of felodipine and the conformation of these polymers adsorbed to crystalline felodipine was investigated in order to gain a mechanistic understanding of crystal growth inhibition. It was determined that polymer hydrophobicity impacted polymer adsorption as well as adsorbed polymer conformation. Polymer conformation impacts its surface coverage, which was shown to directly correlate to the polymer's effectiveness as a growth rate inhibitor. By modeling this correlation, it is possible to predict polymer effectiveness given the surface coverage of the polymer.

  12. MAG, myelin and overcoming growth inhibition in the CNS

    PubMed Central

    McKerracher, Lisa; Rosen, Kenneth M.

    2015-01-01

    While neurons in the central nervous system (CNS) have the capacity to regenerate their axons after injury, they fail to do so, in part because regeneration is limited by growth inhibitory proteins present in CNS myelin. Myelin-associated glycoprotein (MAG) was the first myelin-derived growth inhibitory protein identified, and its inhibitory activity was initially elucidated in 1994 independently by the Filbin lab and the McKerracher lab using cell-based and biochemical techniques, respectively. Since that time we have gained a wealth of knowledge concerning the numerous growth inhibitory proteins that are present in myelin, and we also have dissected many of the neuronal signaling pathways that act as stop signs for axon regeneration. Here we give an overview of the early research efforts that led to the identification of myelin-derived growth inhibitory proteins, and the importance of this family of proteins for understanding neurotrauma and CNS diseases. We further provide an update on how this knowledge has been translated towards current clinical studies in regenerative medicine. PMID:26441514

  13. Sugar-induced plant growth is dependent on brassinosteroids.

    PubMed

    Zhang, Yongqiang; He, Junxian

    2015-01-01

    Sugars, the end products of photosynthesis, not only fuel growth and development of plants as carbon and energy sources, but also function as signaling molecules to modulate a range of important processes during plant growth and development. We recently found that sugar can promote hypocotyl elongation in Arabidopsis in darkness and this is largely dependent on brassinosteroids (BRs), a group of essential phytohormones involved in mediation of plant cell elongation. Sugars not only positively regulate the transcription of BZR1, the gene encoding the BR-activated transcription factor BRASSINAZOLE RESISTANT1 (BRZ1), but also stabilize the BZR1 protein. Based on these results, we proposed that BZR1 may act as a converging node for crosstalk between BR and sugar signaling in regulating plant growth in darkness. In this short communication, we present some new data showing that HEXOKINASE1 (HXK1), the first identified glucose (Glc) sensor in plants, was positively involved in Glc promotion of hypocotyl elongation in Arabidopsis in the dark. It appears that the function of HXK1 is dependent on the presence of BR, suggesting that BR may act downstream of HXK1 to positively regulate Glc-induced hypocotyl elongation in Arabidopsis in darkness.

  14. Inhibition of the growth of Lewis lung carcinoma by indomethacin in conventional, nude, and beige mice.

    PubMed

    Maca, R D

    1988-12-01

    The effects of a prostaglandin synthesis inhibitor, indomethacin (Indo), on the growth of Lewis lung carcinoma (LLC) growing as primary subcutaneous tumors in either conventional C57BL/6 mice, T cell deficient nude mice, or natural killer (NK) cell deficient beige mice were studied. In conventional mice, Indo, when continuously administered in the drinking water, consistently and significantly inhibited, in a dose-related fashion, the growth of LLC implanted either subcutaneously in the footpad or in the inguinal region; however, the degree of inhibition of footpad tumor appeared to be greater than that of inguinal tumor. Maximum inhibition was found when Indo was initiated before detectable or measurable tumor developed. If Indo treatment was initiated after tumor growth was evident, then Indo was found to be less effective, although significant inhibition was still observed. Indo also effectively inhibited LLC growing either in the footpad or in the inguinal region of nude or beige mice. The degree of inhibition of both footpad and inguinal tumors in both these mice was comparable to that seen in conventional C57BL/6 mice, indicating that mature T cells, NK cells, or soluble products produced only by these cells are not involved in mediating or modulating the inhibitory effects of Indo on LLC growth. Although Indo treatment significantly inhibited LLC growth in vivo, continuous treatment of cultured LLC cells with Indo in vitro did not decrease the growth of cultured cells. These results indicate that the inhibitory effect of Indo in vivo is not the result of a direct inhibitory effect of Indo on these tumor cells. Lastly, this inhibitory effect of Indo in vivo could not be reversed or negated, not even in part, by the simultaneous, daily i.p. administration of 16,16-dimethyl-PGE2. This finding suggests that the inhibitory effect of Indo involves a mechanism other than the inhibition of prostaglandin E2 production. PMID:3216222

  15. Energetics of Streptococcal Growth Inhibition by Hydrostatic Pressure

    PubMed Central

    Matsumura, Philip; Marquis, Robert E.

    1977-01-01

    Growth of Streptococcus faecalis in complex media with various fuel sources appeared to be limited by the rate of supply of adenosine-5′ -triphosphate (ATP) at 1 atm and also under 408 atm of hydrostatic pressure. Growth under pressure was energetically inefficient, as indicated by an average cell yield for exponentially growing cultures of only 10.7 g (dry weight) per mol of ATP produced compared with a 1-atm value of 15.6. Use of ATP for pressure-volume work or for turnover of protein, peptidoglycan, or stable ribonucleic acid (RNA) did not appear to be significant causes of growth inefficiency under pressure. In addition, there did not seem to be an increased ATP requirement for ion uptake because cells growing at 408 atm had significantly lower internal K+ levels than did those growing at 1 atm. Pressure did stimulate the membrane adenosine triphosphatase (ATPase) or S. faecalis at ATP concentrations greater than 0.5 mM. Intracellular ATP levels were found to vary during the culture cycle from about 2.5 μmol/ml of cytoplasmic water for lag-phase or stationary-phase cells to maxima for exponentially growing cells of about 7.5 μmol/ml at 1 atm and 5.5 μmol/ml at 408 atm. N,N′-dicyclohexylcarbodiimide at a 10 μM concentration improved growth efficiency under pressure, as did Mg2+ or Ca2+ ions at 50 mM concentration. These agents also enhanced ATP pooling, and it seemed that at least part of the growth inefficiency under pressure was due to increased ATPase activity. In all, it appeared that S. faecalis growing under pressure has somewhat reduced ATP supply but significantly increased demand and that the inhibitory effects of pressure can be interpreted largely in terms of ATP supply and demand. PMID:405925

  16. Anti-histone acetyltransferase activity from allspice extracts inhibits androgen receptor-dependent prostate cancer cell growth.

    PubMed

    Lee, Yoo-Hyun; Hong, Soon Won; Jun, Woojin; Cho, Hong Yon; Kim, Han-Cheon; Jung, Myung Gu; Wong, Jiemin; Kim, Ha-Il; Kim, Chang-Hoon; Yoon, Ho-Geun

    2007-11-01

    Histone acetylation depends on the activity of two enzyme families, histone acetyltransferase (HAT) and deacetylase (HDAC). In this study, we screened various plant extracts to find potent HAT inhibitors. Hot water extracts of allspice inhibited HAT activity, especially p300 and CBP (40% at 100 microg/ml). The mRNA levels of two androgen receptor (AR) regulated genes, PSA and TSC22, decreased with allspice treatment (100 microg/ml). Importantly, in IP western analysis, AR acetylation was dramatically decreased by allspice treatment.Furthermore, chromatin immunoprecipitation indicated that the acetylation of histone H3 in the PSA and B2M promoter regions was also repressed. Finally, allspice treatment reduced the growth of human prostate cancer cells, LNCaP (50% growth inhibition at 200 microg/ml). Taken together, our data indicate that the potent HAT inhibitory activity of allspice reduced AR and histone acetylation and led to decreased transcription of AR target genes, resulting in inhibition of prostate cancer cell growth.

  17. Mixed planting with a leguminous plant outperforms bacteria in promoting growth of a metal remediating plant through histidine synthesis.

    PubMed

    Adediran, Gbotemi A; Ngwenya, Bryne T; Mosselmans, J Frederick W; Heal, Kate V; Harvie, Barbra A

    2016-01-01

    The effectiveness of plant growth promoting bacteria (PGPB) in improving metal phytoremediation is still limited by stunted plant growth under high soil metal concentrations. Meanwhile, mixed planting with leguminous plants is known to improve yield in nutrient deficient soils but the use of a metal tolerant legume to enhance metal tolerance of a phytoremediator has not been explored. We compared the use of Pseudomonas brassicacearum, Rhizobium leguminosarum, and the metal tolerant leguminous plant Vicia sativa to promote the growth of Brassica juncea in soil contaminated with 400 mg Zn kg(-1), and used synchrotron based microfocus X-ray absorption spectroscopy to probe Zn speciation in plant roots. B. juncea grew better when planted with V. sativa than when inoculated with PGPB. By combining PGPB with mixed planting, B. juncea recovered full growth while also achieving soil remediation efficiency of >75%, the maximum ever demonstrated for B. juncea. μXANES analysis of V. sativa suggested possible root exudation of the Zn chelates histidine and cysteine were responsible for reducing Zn toxicity. We propose the exploration of a legume-assisted-phytoremediation system as a more effective alternative to PGPB for Zn bioremediation. PMID:26682469

  18. Root and bacterial secretions regulate the interaction between plants and PGPR leading to distinct plant growth promotion effects

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant growth-promoting rhizobacteria (PGPR) have garnered interest in agriculture due to their ability to influence the growth and production of host plants. ATP-binding cassette (ABC) transporters play important roles in plant-microbe interactions by modulating plant root exudation. The present stu...

  19. Proximity-Dependent Inhibition of Growth of Mannheimia haemolytica by Pasteurella multocida

    PubMed Central

    Bavananthasivam, Jegarubee; Dassanayake, Rohana P.; Kugadas, Abirami; Shanthalingam, Sudarvili; Call, Douglas R.; Knowles, Donald P.

    2012-01-01

    Mannheimia haemolytica, Pasteurella multocida, and Bibersteinia trehalosi have been identified in the lungs of pneumonic bighorn sheep (BHS; Ovis canadensis). Of these pathogens, M. haemolytica has been shown to consistently cause fatal pneumonia in BHS under experimental conditions. However, M. haemolytica has been isolated by culture less frequently than the other bacteria. We hypothesized that the growth of M. haemolytica is inhibited by other bacteria in the lungs of BHS. The objective of this study was to determine whether P. multocida inhibits the growth of M. haemolytica. Although in monoculture both bacteria exhibited similar growth characteristics, in coculture with P. multocida there was a clear inhibition of growth of M. haemolytica. The inhibition was detected at mid-log phase and continued through the stationary phase. When cultured in the same medium, the growth of M. haemolytica was inhibited when both bacteria were separated by a membrane that allowed contact (pore size, 8.0 μm) but not when they were separated by a membrane that limited contact (pore size, 0.4 μm). Lytic bacteriophages or bactericidal compounds could not be detected in the culture supernatant fluid from monocultures of P. multocida or from P. multocida-M. haemolytica cocultures. These results indicate that P. multocida inhibits the growth of M. haemolytica by a contact- or proximity-dependent mechanism. If the inhibition of growth of M. haemolytica by P. multocida occurs in vivo as well, it could explain the inconsistent isolation of M. haemolytica from the lungs of pneumonic BHS. PMID:22798357

  20. Fungicides effectively used for growth inhibition of several fungi could induce mycotoxin biosynthesis in toxigenic species.

    PubMed

    Schmidt-Heydt, M; Stoll, D; Geisen, R

    2013-09-16

    Seven different commercial fungicides (Aliette, Rovral, Cantus, Ortiva, Luna Experience, Fenomenal and Mancozeb) were tested for their ability to inhibit the growth of the fungal species Penicillium nordicum, Penicillium verrucosum, Verticillium dahliae and Cladosporium sp. In case of the mycotoxigenic strains P. nordicum and P. verrucosum, the biosynthesis of the mycotoxins ochratoxin and citrinin was determined. Interestingly individual fungicides were only able to inhibit the growth of the analyzed fungi to some extent. In case of P. verrucosum the fungicide "Rovral", an iprodion belonging to the substance class of imidazoles, led to a decrease in the growth rate but to a strong induction of mycotoxin biosynthesis as has been described earlier for the strobilurins. Consequently before using a given fungicide to protect crops and enhance storage life, the applicability of this chemical compound should be tested not only for its ability to inhibit fungal growth but also for its effect on level of secondary metabolite biosynthesis. PMID:24036489

  1. Fungicides effectively used for growth inhibition of several fungi could induce mycotoxin biosynthesis in toxigenic species.

    PubMed

    Schmidt-Heydt, M; Stoll, D; Geisen, R

    2013-09-16

    Seven different commercial fungicides (Aliette, Rovral, Cantus, Ortiva, Luna Experience, Fenomenal and Mancozeb) were tested for their ability to inhibit the growth of the fungal species Penicillium nordicum, Penicillium verrucosum, Verticillium dahliae and Cladosporium sp. In case of the mycotoxigenic strains P. nordicum and P. verrucosum, the biosynthesis of the mycotoxins ochratoxin and citrinin was determined. Interestingly individual fungicides were only able to inhibit the growth of the analyzed fungi to some extent. In case of P. verrucosum the fungicide "Rovral", an iprodion belonging to the substance class of imidazoles, led to a decrease in the growth rate but to a strong induction of mycotoxin biosynthesis as has been described earlier for the strobilurins. Consequently before using a given fungicide to protect crops and enhance storage life, the applicability of this chemical compound should be tested not only for its ability to inhibit fungal growth but also for its effect on level of secondary metabolite biosynthesis.

  2. Computational Morphodynamics: A modeling framework to understand plant growth

    PubMed Central

    Chickarmane, Vijay; Roeder, Adrienne H.K.; Tarr, Paul T.; Cunha, Alexandre; Tobin, Cory; Meyerowitz, Elliot M.

    2014-01-01

    Computational morphodynamics utilizes computer modeling to understand the development of living organisms over space and time. Results from biological experiments are used to construct accurate and predictive models of growth. These models are then used to make novel predictions providing further insight into the processes in question, which can be tested experimentally to either confirm or rule out the validity of the computational models. This review highlights two fundamental issues: (1.) models should span and integrate single cell behavior with tissue development and (2.) the necessity to understand the feedback between mechanics of growth and chemical or molecular signaling. We review different approaches to model plant growth and discuss a variety of model types that can be implemented, with the aim of demonstrating how this methodology can be used, to explore the morphodynamics of plant development. PMID:20192756

  3. (Mechanisms of inhibition of viral replication in plants)

    SciTech Connect

    Not Available

    1991-01-01

    During the last year we have made a number of important observations in the fields of virology and plant molecular biology. By directly sequencing Tomato Mosaic Virus (ToMV) movement genes, previously undetected sequence alterations common to specific viral strains were found. The difficulty in regenerating transgenic tomato plants containing the Tm-2 gene was overcome. Tobacco plants transformed with Cucumber Mosaic Virus (CMV) are being characterized. Analysis of transgenic tobacco plants expressing CMV coat protein have shown no correlation between coat protein expression and level of resistance. Specific amino acid changes have been found to correlate with CMV resistance breaking and degree of pathogenicity. Satellite RNAs are shown to be too unstable for use as a biological control agent. The aphid transmission domain CMV has been localized to one (or more) of three amino acids; constructs have been made to determine the exact amino acids involved. 15 refs.

  4. l-Methionine inhibits growth of human pancreatic cancer cells

    PubMed Central

    Benavides, Maximo A.; Bosland, Maarten C.; da Silva, Cássio P.; Sares, Claudia T. Gomes; de Oliveira, Alana M. Cerqueira; Kemp, Rafael; dos Reis, Rodolfo B.; Martins, Vilma R.; Sampaio, Suely V.; Bland, Kirby I.; Grizzle, William E.; dos Santos, José S.

    2015-01-01

    We have previously shown that l-methionine inhibits proliferation of breast, prostate, and colon cancer cells. This study extends these findings to BXPC-3 (mutated p53) and HPAC (wild-type p53) pancreatic cancer cells and explores the reversibility of these effects. Cells were exposed to l-methionine (5 mg/ml) for 7 days or for 3 days, followed by 4 days of culture without l-methionine (recovery). Cell proliferation, apoptosis, and cell cycle effects were assessed by flow cytometry after staining for Ki-67 or annexin V/propidium iodide. Cell proliferation was reduced by 31–35% after 7 days of methionine exposure; the effect persisted in BXPC-3 and HPAC cells after 4 days of recovery. Methionine increased apoptosis by 40–75% in HPAC cells, but not in BXPC-3 cells. Continuous exposure to methionine caused accumulation of BXPC-3 cells in the S phase and HPAC cells in both the G0/G1 and S phases; however, after 4 days of recovery, these effects disappeared. In conclusion, l-methionine inhibits proliferation and interferes with the cell cycle of BXPC-3 and HPAC pancreatic cancer cells; the effects on apoptosis remarkably persisted after methionine withdrawal. Apoptosis was induced only in BXPC-3 cells. Some of the differences in the effects of methionine between cell lines may be related to disparate p53 status. These findings warrant further studies on the potential therapeutic benefit of l-methionine against pancreatic cancer. PMID:24126240

  5. L-Methionine inhibits growth of human pancreatic cancer cells.

    PubMed

    Benavides, Maximo A; Bosland, Maarten C; da Silva, Cássio P; Gomes Sares, Claudia T; de Oliveira, Alana M Cerqueira; Kemp, Rafael; dos Reis, Rodolfo B; Martins, Vilma R; Sampaio, Suely V; Bland, Kirby I; Grizzle, William E; dos Santos, José S

    2014-02-01

    We have previously shown that L-methionine inhibits proliferation of breast, prostate, and colon cancer cells. This study extends these findings to BXPC-3 (mutated p53) and HPAC (wild-type p53) pancreatic cancer cells and explores the reversibility of these effects. Cells were exposed to L-methionine (5 mg/ml) for 7 days or for 3 days, followed by 4 days of culture without L-methionine (recovery). Cell proliferation, apoptosis, and cell cycle effects were assessed by flow cytometry after staining for Ki-67 or annexin V/propidium iodide. Cell proliferation was reduced by 31-35% after 7 days of methionine exposure; the effect persisted in BXPC-3 and HPAC cells after 4 days of recovery. Methionine increased apoptosis by 40-75% in HPAC cells, but not in BXPC-3 cells. Continuous exposure to methionine caused accumulation of BXPC-3 cells in the S phase and HPAC cells in both the G0/G1 and S phases; however, after 4 days of recovery, these effects disappeared. In conclusion, L-methionine inhibits proliferation and interferes with the cell cycle of BXPC-3 and HPAC pancreatic cancer cells; the effects on apoptosis remarkably persisted after methionine withdrawal. Apoptosis was induced only in BXPC-3 cells. Some of the differences in the effects of methionine between cell lines may be related to disparate p53 status. These findings warrant further studies on the potential therapeutic benefit of L-methionine against pancreatic cancer.

  6. Plant growth promoting bacteria from Crocus sativus rhizosphere.

    PubMed

    Ambardar, Sheetal; Vakhlu, Jyoti

    2013-12-01

    Present study deals with the isolation of rhizobacteria and selection of plant growth promoting bacteria from Crocus sativus (Saffron) rhizosphere during its flowering period (October-November). Bacterial load was compared between rhizosphere and bulk soil by counting CFU/gm of roots and soil respectively, and was found to be ~40 times more in rhizosphere. In total 100 bacterial isolates were selected randomly from rhizosphere and bulk soil (50 each) and screened for in-vitro and in vivo plant growth promoting properties. The randomly isolated bacteria were identified by microscopy, biochemical tests and sequence homology of V1-V3 region of 16S rRNA gene. Polyphasic identification categorized Saffron rhizobacteria and bulk soil bacteria into sixteen different bacterial species with Bacillus aryabhattai (WRF5-rhizosphere; WBF3, WBF4A and WBF4B-bulk soil) common to both rhizosphere as well as bulk soil. Pseudomonas sp. in rhizosphere and Bacillus and Brevibacterium sp. in the bulk soil were the predominant genera respectively. The isolated rhizobacteria were screened for plant growth promotion activity like phosphate solubilization, siderophore and indole acetic acid production. 50 % produced siderophore and 33 % were able to solubilize phosphate whereas all the rhizobacterial isolates produced indole acetic acid. The six potential PGPR showing in vitro activities were used in pot trial to check their efficacy in vivo. These bacteria consortia demonstrated in vivo PGP activity and can be used as PGPR in Saffron as biofertilizers.This is the first report on the isolation of rhizobacteria from the Saffron rhizosphere, screening for plant growth promoting bacteria and their effect on the growth of Saffron plant.

  7. Characterization of Minnesota lunar simulant for plant growth

    NASA Technical Reports Server (NTRS)

    Oglesby, James P.; Lindsay, Willard L.; Sadeh, Willy Z.

    1993-01-01

    Processing of lunar regolith into a plant growth medium is crucial in the development of a regenerative life support system for a lunar base. Plants, which are the core of such a system, produce food and oxygen for humans and, at the same time, consume carbon dioxide. Because of the scarcity of lunar regolith, simulants must be used to infer its properties and to develop procedures for weathering and chemical analyses. The Minnesota Lunar Simulant (MLS) has been identified to date as the best available simulant for lunar regolith. Results of the dissolution studies reveal that appropriately fertilized MLS can be a suitable medium for plant growth. The techniques used in conducting these studies can be extended to investigate the suitability of actual lunar regolith as a plant growth medium. Dissolution experiments were conducted using the MLS to determine its nutritional and toxicity characteristics for plant growth and to develop weathering and chemical analysis techniques. Two weathering regimes, one with water and one with dilute organic acids simulating the root rhizosphere microenvironment, were investigated. Elemental concentrations were measured using inductively-coupled-plasma (ICP) emission spectrometry and ion chromatography (IC). The geochemical speciation model, MINTEQA2, was used to determine the major solution species and the minerals controlling them. Acidification was found to be a useful method for increasing cation concentrations to meaningful levels. Initial results indicate that MLS weathers to give neutral to slightly basic solutions which contain acceptable amounts of the essential elements required for plant nutrition (i.e., potassium, calcium, magnesium, sulfur, zinc, sodium, silicon, manganese, copper, chlorine, boron, molybdenum, and cobalt). Elements that need to be supplemented include carbon, nitrogen, and perhaps phosphorus and iron. Trace metals in solution were present at nontoxic levels.

  8. Antioxidant and nitric oxide inhibition activities of Thai medicinal plants.

    PubMed

    Makchuchit, Sunita; Itharat, Arunporn; Tewtrakul, Supinya

    2010-12-01

    Nineteen Thai medicinal plants used in Thai traditional medicine preparation to treat colds, asthma and fever were studied for their antioxidant and NO inhibitory activities. Three extracts were obtained from each plant. First extract obtained by macerating the plant part in 95% ethanol (Et) residue was boiled in water, where water extract (EW) was obtained. The third extract (HW) was obtained by boiling each plant in water similar to that of Thai traditional medicine practice. These extracts were tested for their antioxidant activity using DPPH assay, and anti-inflammatory activity by determination of inhibitory activity on lipopolysaccharide (LPS) induced nitric oxide (NO) production in RAW 264.7 cell lines using Griess reagent. Results indicated that Et, EW and HW of Syzygium aromaticum showed the highest antioxidant activity (EC50 = 6.56, 4.73 and 5.30 microg/ml, respectively). Et of Atractylodes lancea exhibited the most potent inhibitory activity on lipopolysaccharide (LPS) induced nitric oxide (NO) production in RAW 264.7 cells, with IC50 value of 9.70 microg/ml, followed by Et of Angelica sinensis and Cuminum cyminum (IC50 = 12.52 and 13.56 microg/ml, respectively) but water extract (EW, HW) of all plants were apparently inactive. These results of anti-inflammatory activity of these plants correspond with the traditional use for fever; cold, allergic-related diseases and inflammatory-related diseases. PMID:21294419

  9. Phosphorus mobilizing consortium Mammoth P™ enhances plant growth

    PubMed Central

    Bell, Colin; Mancini, Lauren M.; Lee, Melanie N.; Conant, Richard T.; Wallenstein, Matthew D.

    2016-01-01

    Phosphorus (P) is a critical nutrient used to maximize plant growth and yield. Current agriculture management practices commonly experience low plant P use efficiency due to natural chemical sorption and transformations when P fertilizer is applied to soils. A perplexing challenge facing agriculture production is finding sustainable solutions to deliver P more efficiently to plants. Using prescribed applications of specific soil microbial assemblages to mobilize soil bound—P to improve crop nutrient uptake and productivity has rarely been employed. We investigated whether inoculation of soils with a bacterial consortium developed to mobilize soil P, named Mammoth PTM, could increase plant productivity. In turf, herbs, and fruits, the combination of conventional inorganic fertilizer combined with Mammoth PTM increased productivity up to twofold compared to the fertilizer treatments without the Mammoth PTM inoculant. Jalapeño plants were found to bloom more rapidly when treated with either Mammoth P. In wheat trials, we found that Mammoth PTM by itself was able to deliver yields equivalent to those achieved with conventional inorganic fertilizer applications and improved productivity more than another biostimulant product. Results from this study indicate the substantial potential of Mammoth PTM to enhance plant growth and crop productivity. PMID:27326379

  10. Phosphorus mobilizing consortium Mammoth P(™) enhances plant growth.

    PubMed

    Baas, Peter; Bell, Colin; Mancini, Lauren M; Lee, Melanie N; Conant, Richard T; Wallenstein, Matthew D

    2016-01-01

    Phosphorus (P) is a critical nutrient used to maximize plant growth and yield. Current agriculture management practices commonly experience low plant P use efficiency due to natural chemical sorption and transformations when P fertilizer is applied to soils. A perplexing challenge facing agriculture production is finding sustainable solutions to deliver P more efficiently to plants. Using prescribed applications of specific soil microbial assemblages to mobilize soil bound-P to improve crop nutrient uptake and productivity has rarely been employed. We investigated whether inoculation of soils with a bacterial consortium developed to mobilize soil P, named Mammoth P(TM), could increase plant productivity. In turf, herbs, and fruits, the combination of conventional inorganic fertilizer combined with Mammoth P(TM) increased productivity up to twofold compared to the fertilizer treatments without the Mammoth P(TM) inoculant. Jalapeño plants were found to bloom more rapidly when treated with either Mammoth P. In wheat trials, we found that Mammoth P(TM) by itself was able to deliver yields equivalent to those achieved with conventional inorganic fertilizer applications and improved productivity more than another biostimulant product. Results from this study indicate the substantial potential of Mammoth P(TM) to enhance plant growth and crop productivity. PMID:27326379

  11. Herbivory: effects on plant abundance, distribution and population growth

    PubMed Central

    Maron, John L; Crone, Elizabeth

    2006-01-01

    Plants are attacked by many different consumers. A critical question is how often, and under what conditions, common reductions in growth, fecundity or even survival that occur due to herbivory translate to meaningful impacts on abundance, distribution or dynamics of plant populations. Here, we review population-level studies of the effects of consumers on plant dynamics and evaluate: (i) whether particular consumers have predictably more or less influence on plant abundance, (ii) whether particular plant life-history types are predictably more vulnerable to herbivory at the population level, (iii) whether the strength of plant–consumer interactions shifts predictably across environmental gradients and (iv) the role of consumers in influencing plant distributional limits. Existing studies demonstrate numerous examples of consumers limiting local plant abundance and distribution. We found larger effects of consumers on grassland than woodland forbs, stronger effects of herbivory in areas with high versus low disturbance, but no systematic or unambiguous differences in the impact of consumers based on plant life-history or herbivore feeding mode. However, our ability to evaluate these and other patterns is limited by the small (but growing) number of studies in this area. As an impetus for further study, we review strengths and challenges of population-level studies, such as interpreting net impacts of consumers in the presence of density dependence and seed bank dynamics. PMID:17002942

  12. Inhibition of intracellular growth of Listeria monocytogenes by antibiotics.

    PubMed Central

    Michelet, C; Avril, J L; Cartier, F; Berche, P

    1994-01-01

    We studied the activities of 15 antibiotics on the intracellular growth of Listeria monocytogenes in a HeLa cell line. After 24 h of contact with the infected cells, the antibiotics most effective against the intracellular growth of the 10 strains tested were amoxicillin, temafloxacin, and sparfloxacin, which nevertheless failed to totally eliminate the intracellular bacteria. Rifampin and co-trimoxazole had variable effects, depending on the isolates studied. The most active combinations were amoxicillin-sparfloxacin, co-trimoxazole-gentamicin, and sparfloxacin-co-trimoxazole. The results suggest the value of using a cell culture technique to study the activities of antibiotics against certain bacteria with intracellular sites of multiplication. PMID:8203836

  13. SIAH-1 inhibits cell growth by altering the mitotic process.

    PubMed

    Bruzzoni-Giovanelli, H; Faille, A; Linares-Cruz, G; Nemani, M; Le Deist, F; Germani, A; Chassoux, D; Millot, G; Roperch, J P; Amson, R; Telerman, A; Calvo, F

    1999-11-25

    SIAH-1, the human homologue of the drosophila seven in absentia gene, is a p53-p21Waf-1 inducible gene. We report that stable transfection with SIAH-1 of the epithelial breast cancer cell line MCF-7 blocks its growth process. The transfectants show a redistribution of SIAH-1 protein within the nucleus, more specifically to the nuclear matrix, associated to dramatic changes in cell morphology and defective mitosis. Multinucleated giant cells (2-12 nuclei in more than 50% cells) were a most striking observation associated with tubulin spindle disorganization and defective cytokinesis. There were also present at high frequency abortive mitotic figures, DNA bridges and persistance of intercellular bridges and midbodies, along with an increased expression of p21Waf-1. These results indicate that the mechanism of growth arrest induced by SIAH-1 in MCF-7 cells involves disorganization of the mitotic program, mainly during nuclei separation and cytokinesis.

  14. CH5137291, an androgen receptor nuclear translocation-inhibiting compound, inhibits the growth of castration-resistant prostate cancer cells.

    PubMed

    Ishikura, Nobuyuki; Kawata, Hiromitsu; Nishimoto, Ayako; Nakamura, Ryo; Tsunenari, Toshiaki; Watanabe, Miho; Tachibana, Kazutaka; Shiraishi, Takuya; Yoshino, Hitoshi; Honma, Akie; Emura, Takashi; Ohta, Masateru; Nakagawa, Toshito; Houjo, Takao; Corey, Eva; Vessella, Robert L; Aoki, Yuko; Sato, Haruhiko

    2015-04-01

    Resistance of prostate cancer to castration is currently an unavoidable problem. The major mechanisms underlying such resistance are androgen receptor (AR) overexpression, androgen-independent activation of AR, and AR mutation. To address this problem, we developed an AR pure antagonist, CH5137291, with AR nuclear translocation-inhibiting activity, and compared its activity and characteristics with that of bicalutamide. Cell lines corresponding to the mechanisms of castration resistance were used: LNCaP-BC2 having AR overexpression and LNCaP-CS10 having androgen-independent AR activation. VCaP and LNCaP were used as hormone-sensitive prostate cancer cells. In vitro functional assay clearly showed that CH5137291 inhibited the nuclear translocation of wild-type ARs as well as W741C- and T877A-mutant ARs. In addition, it acted as a pure antagonist on the transcriptional activity of these types of ARs. In contrast, bicalutamide did not inhibit the nuclear translocation of these ARs, and showed a partial/full agonistic effect on the transcriptional activity. CH5137291 inhibited cell growth more strongly than bicalutamide in VCaP and LNCaP cells as well as in LNCaP-BC2 and LNCaP-CS10 cells in vitro. In xenograft models, CH5137291 strongly inhibited the tumor growth of LNCaP, LNCaP-BC2, and LNCaP-CS10, whereas bicalutamide showed a weaker effect in LNCaP and almost no effect in LNCaP-BC2 and LNCaP-CS10 xenografts. Levels of prostate-specific antigen (PSA) in plasma correlated well with the antitumor effect of both agents. CH5137291 inhibited the growth of LNCaP tumors that had become resistant to bicalutamide treatment. A docking model suggested that CH5137291 intensively collided with the M895 residue of helix 12, and therefore strongly inhibited the folding of helix 12, a cause of AR agonist activity, in wild-type and W741C-mutant ARs. In cynomolgus monkeys, the serum concentration of CH5137291 increased dose-dependently and PSA level decreased 80% at 100 mg/kg. CH

  15. Differential growth responses of Brachypodium distachyon genotypes to inoculation with plant growth promoting rhizobacteria.

    PubMed

    do Amaral, Fernanda P; Pankievicz, Vânia C S; Arisi, Ana Carolina M; de Souza, Emanuel M; Pedrosa, Fabio; Stacey, Gary

    2016-04-01

    Plant growth promoting rhizobacteria (PGPR) can associate and enhance the growth of important crop grasses. However, in most cases, the molecular mechanisms responsible for growth promotion are not known. Such research could benefit by the adoption of a grass model species that showed a positive response to bacterial inoculation and was amenable to genetic and molecular research methods. In this work we inoculated different genotypes of the model grass Brachypodium distachyon with two, well-characterized PGPR bacteria, Azospirillum brasilense and Herbaspirillum seropedicae, and evaluated the growth response. Plants were grown in soil under no nitrogen or with low nitrogen (i.e., 0.5 mM KNO3). A variety of growth parameters (e.g., shoot height, root length, number of lateral roots, fresh and dry weight) were measured 35 days after inoculation. The data indicate that plant genotype plays a very important role in determining the plant response to PGPR inoculation. A positive growth response was observed with only four genotypes grown under no nitrogen and three genotypes tested under low nitrogen. However, in contrast, relatively good root colonization was seen with most genotypes, as measured by drop plate counting and direct, microscopic examination of roots. In particular, the endophytic bacteria H. seropedicae showed strong epiphytic and endophytic colonization of roots.

  16. Differential growth responses of Brachypodium distachyon genotypes to inoculation with plant growth promoting rhizobacteria.

    PubMed

    do Amaral, Fernanda P; Pankievicz, Vânia C S; Arisi, Ana Carolina M; de Souza, Emanuel M; Pedrosa, Fabio; Stacey, Gary

    2016-04-01

    Plant growth promoting rhizobacteria (PGPR) can associate and enhance the growth of important crop grasses. However, in most cases, the molecular mechanisms responsible for growth promotion are not known. Such research could benefit by the adoption of a grass model species that showed a positive response to bacterial inoculation and was amenable to genetic and molecular research methods. In this work we inoculated different genotypes of the model grass Brachypodium distachyon with two, well-characterized PGPR bacteria, Azospirillum brasilense and Herbaspirillum seropedicae, and evaluated the growth response. Plants were grown in soil under no nitrogen or with low nitrogen (i.e., 0.5 mM KNO3). A variety of growth parameters (e.g., shoot height, root length, number of lateral roots, fresh and dry weight) were measured 35 days after inoculation. The data indicate that plant genotype plays a very important role in determining the plant response to PGPR inoculation. A positive growth response was observed with only four genotypes grown under no nitrogen and three genotypes tested under low nitrogen. However, in contrast, relatively good root colonization was seen with most genotypes, as measured by drop plate counting and direct, microscopic examination of roots. In particular, the endophytic bacteria H. seropedicae showed strong epiphytic and endophytic colonization of roots. PMID:26873699

  17. Effect of oil refinery sludges on the growth and antioxidant system of alfalfa plants.

    PubMed

    Martí, M Carmen; Camejo, Daymi; Fernández-García, Nieves; Rellán-Alvarez, Rubén; Marques, Silvia; Sevilla, Francisca; Jiménez, Ana

    2009-11-15

    The refining process in the petrochemical industry generates oil refinery sludges, a potentially contaminating waste product, with a high content of hydrocarbons and heavy metals. Faster degradation of hydrocarbons has been reported in vegetated soils than in non-vegetated soils, but the impact of these contaminants on the plants physiology and on their antioxidant system is not well known. In this study, the effect of the addition of petroleum sludge to soil on the physiological parameters, nutrient contents, and oxidative and antioxidant status in alfalfa was investigated. An inhibition of alfalfa growth and an induction of oxidative stress, as indicated by an increase in protein oxidation, were found. Also, the superoxide dismutase isoenzymes, peroxidase, and those enzymes involved in the ascorbate-glutathione cycle showed significant activity increases, parallel to an enhancement of total homoglutathione, allowing plants being tolerant to this situation. This information is necessary to establish successful and sustainable plant-based remediation strategies.

  18. Inhibiting Delta-6 Desaturase Activity Suppresses Tumor Growth in Mice

    PubMed Central

    He, Chengwei; Qu, Xiying; Wan, Jianbo; Rong, Rong; Huang, Lili; Cai, Chun; Zhou, Keyuan; Gu, Yan; Qian, Steven Y.; Kang, Jing X.

    2012-01-01

    Recent studies have shown that a tumor-supportive microenvironment is characterized by high levels of pro-inflammatory and pro-angiogenic eicosanoids derived from omega-6 (n−6) arachidonic acid (AA). Although the metabolic pathways (COX, LOX, and P450) that generate these n−6 AA eicosanoids have been targeted, the role of endogenous AA production in tumorigenesis remains unexplored. Delta-6 desaturase (D6D) is the rate-limiting enzyme responsible for the synthesis of n−6 AA and increased D6D activity can lead to enhanced n−6 AA production. Here, we show that D6D activity is upregulated during melanoma and lung tumor growth and that suppressing D6D activity, either by RNAi knockdown or a specific D6D inhibitor, dramatically reduces tumor growth. Accordingly, the content of AA and AA-derived tumor-promoting metabolites is significantly decreased. Angiogenesis and inflammatory status are also reduced. These results identify D6D as a key factor for tumor growth and as a potential target for cancer therapy and prevention. PMID:23112819