메뉴 건너뛰기




Volumn 74, Issue 3, 2011, Pages 431-438

Allelopatic effects of cyanobacteria extracts containing microcystins on Medicago sativa-Rhizobia symbiosis

Author keywords

Cyanotoxins; Irrigation water; Legume plants; Medicago sativa; Nodules; Rhizobia; Symbiosis

Indexed keywords

LAKE WATER; MICROCYSTIN;

EID: 79951959959     PISSN: 01476513     EISSN: 10902414     Source Type: Journal    
DOI: 10.1016/j.ecoenv.2010.10.006     Document Type: Article
Times cited : (46)

References (49)
  • 1
    • 0001267837 scopus 로고    scopus 로고
    • Microcystin-LR inhibits photosynthesis of Phaseolus vulgaris primary leaves: implications for current spray irrigation practice
    • Abe T., Lawson T., Weyers J.D.B., Codd G.A. Microcystin-LR inhibits photosynthesis of Phaseolus vulgaris primary leaves: implications for current spray irrigation practice. New Phytol. 1996, 133:651-658.
    • (1996) New Phytol. , vol.133 , pp. 651-658
    • Abe, T.1    Lawson, T.2    Weyers, J.D.B.3    Codd, G.A.4
  • 2
    • 84983392009 scopus 로고
    • Ascorbate peroxidase: a hydrogen peroxide scavenging enzyme in plants
    • Asada K. Ascorbate peroxidase: a hydrogen peroxide scavenging enzyme in plants. Physiol. Plant. 1992, 85:235-241.
    • (1992) Physiol. Plant. , vol.85 , pp. 235-241
    • Asada, K.1
  • 3
    • 33645233343 scopus 로고    scopus 로고
    • Exploring the natural role of microcystins-a review of effects on photoautotrophic organisms
    • Babica P., Blaha L., Marsalek B. Exploring the natural role of microcystins-a review of effects on photoautotrophic organisms. J. Phycol. 2006, 42:9-20.
    • (2006) J. Phycol. , vol.42 , pp. 9-20
    • Babica, P.1    Blaha, L.2    Marsalek, B.3
  • 4
    • 0000801813 scopus 로고
    • Photon yield of O2 evolution and chlorophyll fluorescence characteristics at 77K among vascular plants of diverse origins
    • Björkman O., Demmig B. Photon yield of O2 evolution and chlorophyll fluorescence characteristics at 77K among vascular plants of diverse origins. Planta 1987, 170:489-504.
    • (1987) Planta , vol.170 , pp. 489-504
    • Björkman, O.1    Demmig, B.2
  • 5
    • 0017184389 scopus 로고
    • A rapid and sensitive method for the quantification of microgram quantities of proteins utilizing the principle of protein-dye binding
    • Bradford M.M. A rapid and sensitive method for the quantification of microgram quantities of proteins utilizing the principle of protein-dye binding. Anal. Biochem. 1976, 72:248-254.
    • (1976) Anal. Biochem. , vol.72 , pp. 248-254
    • Bradford, M.M.1
  • 6
    • 1642462847 scopus 로고    scopus 로고
    • Effects of microcystins on the growth and the activity of superoxide dismutase and peroxidase of rape (Brassica napus L.) and rice (Oryza sativa L.)
    • Chen J., Song L., Dai J., Gan N., Liu Z. Effects of microcystins on the growth and the activity of superoxide dismutase and peroxidase of rape (Brassica napus L.) and rice (Oryza sativa L.). Toxicon 2004, 43:393-400.
    • (2004) Toxicon , vol.43 , pp. 393-400
    • Chen, J.1    Song, L.2    Dai, J.3    Gan, N.4    Liu, Z.5
  • 7
    • 0029416317 scopus 로고
    • Cyanobacterial toxins: occurrence, properties and biological significance
    • Codd G.A. Cyanobacterial toxins: occurrence, properties and biological significance. Water Sci. Technol. 1995, 32:149-156.
    • (1995) Water Sci. Technol. , vol.32 , pp. 149-156
    • Codd, G.A.1
  • 8
    • 0032949659 scopus 로고    scopus 로고
    • Retention of Microcystis aeruginosa and microcystin by salad lettuce (Lactuca sativa) after spray irrigation with water containing cyanobacteria
    • Codd G.A., Metcalf J.S., Beattie K.A. Retention of Microcystis aeruginosa and microcystin by salad lettuce (Lactuca sativa) after spray irrigation with water containing cyanobacteria. Toxicon 1999, 37:1181-1185.
    • (1999) Toxicon , vol.37 , pp. 1181-1185
    • Codd, G.A.1    Metcalf, J.S.2    Beattie, K.A.3
  • 9
    • 41449113167 scopus 로고    scopus 로고
    • Effect of irrigation with lake water containing microcystins on microcystin content and growth of ryegrass, clover, rape, and lettuce
    • Crush J.R., Briggs L.R., Sprosen J.M., Nichols S.N. Effect of irrigation with lake water containing microcystins on microcystin content and growth of ryegrass, clover, rape, and lettuce. Environ. Toxicol. 2008, 23:246-252.
    • (2008) Environ. Toxicol. , vol.23 , pp. 246-252
    • Crush, J.R.1    Briggs, L.R.2    Sprosen, J.M.3    Nichols, S.N.4
  • 10
    • 0032124844 scopus 로고    scopus 로고
    • The toxicology of microcystins
    • Dawson R.M. The toxicology of microcystins. Toxicon 1998, 36:953-962.
    • (1998) Toxicon , vol.36 , pp. 953-962
    • Dawson, R.M.1
  • 11
    • 31544477132 scopus 로고    scopus 로고
    • Cyanobacterial toxins-occurrence, biosynthesis and impact on human affairs
    • Dittmann E., Weigand C. Cyanobacterial toxins-occurrence, biosynthesis and impact on human affairs. Mol. Nutr. Food Res. 2006, 50:7-11.
    • (2006) Mol. Nutr. Food Res. , vol.50 , pp. 7-11
    • Dittmann, E.1    Weigand, C.2
  • 13
    • 74349088639 scopus 로고    scopus 로고
    • Identification and quantification of cyanobacterial toxins (microcystins) in two Moroccan drinking water reservoirs (Mansour Eddahbi, Almassira)
    • Douma M., Ouahid Y., Del Campo F.F., Loudiki M., Mouhri Kh., Oudra B. Identification and quantification of cyanobacterial toxins (microcystins) in two Moroccan drinking water reservoirs (Mansour Eddahbi, Almassira). Environ. Monit. Assessment 2009, 160:439-450.
    • (2009) Environ. Monit. Assessment , vol.160 , pp. 439-450
    • Douma, M.1    Ouahid, Y.2    Del Campo, F.F.3    Loudiki, M.4    Mouhri, K.5    Oudra, B.6
  • 14
    • 0028812034 scopus 로고
    • Somatic embryogenesis and analyze of peroxidase in Phoenix dactylifera L
    • El Hadrami I., Baaziz M. Somatic embryogenesis and analyze of peroxidase in Phoenix dactylifera L. Biol. Plant. 1995, 37:197-203.
    • (1995) Biol. Plant. , vol.37 , pp. 197-203
    • El Hadrami, I.1    Baaziz, M.2
  • 15
    • 2442511283 scopus 로고    scopus 로고
    • A sinapic derivative as induced compound of date palm against Fusarium oxysporum f. Sp. albidinis, the agent causing bayoud disease
    • El Hadrami I., Ramos T., El Bellaj M., Idrissi El, Tourane A., Macheix J.J. A sinapic derivative as induced compound of date palm against Fusarium oxysporum f. Sp. albidinis, the agent causing bayoud disease. Phytopathology 1997, 145:329-333.
    • (1997) Phytopathology , vol.145 , pp. 329-333
    • El Hadrami, I.1    Ramos, T.2    El Bellaj, M.3    Idrissi, E.4    Tourane, A.5    Macheix, J.J.6
  • 16
    • 0038696350 scopus 로고    scopus 로고
    • The Use of Lepidium sativum in a plant bioassay system for the detection of microcystin-LR
    • Gehringer M.M., Kewada V., Coates N., Downing T.G. The Use of Lepidium sativum in a plant bioassay system for the detection of microcystin-LR. Toxicon 2003, 41:871-876.
    • (2003) Toxicon , vol.41 , pp. 871-876
    • Gehringer, M.M.1    Kewada, V.2    Coates, N.3    Downing, T.G.4
  • 17
    • 0037428329 scopus 로고    scopus 로고
    • Microcystin-LR alters the growth, antocyanin content and single stranded DNase activities in Sinapsis alba L. seedlings
    • Hamvas M.M., Mäthe C., Molnär E., Vasas G., Grigorszyky I., Borbely G. Microcystin-LR alters the growth, antocyanin content and single stranded DNase activities in Sinapsis alba L. seedlings. Aquat. Toxicol. 2003, 62:1-9.
    • (2003) Aquat. Toxicol. , vol.62 , pp. 1-9
    • Hamvas, M.M.1    Mäthe, C.2    Molnär, E.3    Vasas, G.4    Grigorszyky, I.5    Borbely, G.6
  • 18
    • 27644546445 scopus 로고    scopus 로고
    • Inhibition of several protein phosphatases by a non-covalently interacting microcystin and a novel cyanobacterial peptide, nostocyclin
    • Hastie C.J., Borthwick E.B., Morrison L.F., Codd G.A., Cohen P.T.W. Inhibition of several protein phosphatases by a non-covalently interacting microcystin and a novel cyanobacterial peptide, nostocyclin. Biochim. Biophys. Acta 2005, 1726:187-193.
    • (2005) Biochim. Biophys. Acta , vol.1726 , pp. 187-193
    • Hastie, C.J.1    Borthwick, E.B.2    Morrison, L.F.3    Codd, G.A.4    Cohen, P.T.W.5
  • 19
    • 0034577228 scopus 로고    scopus 로고
    • Extracellular cyanobacterial substances inhibit microbial growth. Springer-Verlag
    • Heyduck-Söller B., Fischer V. Extracellular cyanobacterial substances inhibit microbial growth. Springer-Verlag. Int. Microbiol. 2000, 3:231-234.
    • (2000) Int. Microbiol. , vol.3 , pp. 231-234
    • Heyduck-Söller, B.1    Fischer, V.2
  • 21
    • 34247139272 scopus 로고    scopus 로고
    • Effects of microcystins on broccoli and mustard, and analysis of accumulated toxin by liquid chromatography-mass spectrometry
    • Järvenpää S., Lundberg-Niinistö C., Spoof L., Sjövall O., Tyystjärvi E., Meriluoto J. Effects of microcystins on broccoli and mustard, and analysis of accumulated toxin by liquid chromatography-mass spectrometry. Toxicon 2007, 49:865-874.
    • (2007) Toxicon , vol.49 , pp. 865-874
    • Järvenpää, S.1    Lundberg-Niinistö, C.2    Spoof, L.3    Sjövall, O.4    Tyystjärvi, E.5    Meriluoto, J.6
  • 22
    • 84989093040 scopus 로고
    • The dissipation of excess excitation energy in British plant species
    • Johnson G.N., Young A.J., Scholes J.D., Horton P. The dissipation of excess excitation energy in British plant species. Plant Cell Environ. 1993, 16:673-679.
    • (1993) Plant Cell Environ. , vol.16 , pp. 673-679
    • Johnson, G.N.1    Young, A.J.2    Scholes, J.D.3    Horton, P.4
  • 23
    • 0028831995 scopus 로고
    • Simple and efficient method for isolation and measurement of cyanobacterial hepatotoxins by plant tests (Sinapis alba L.)
    • Ko's P., Gorzo G., Suranyi G., Borbely G. Simple and efficient method for isolation and measurement of cyanobacterial hepatotoxins by plant tests (Sinapis alba L.). Anal. Biochem. 1995, 225:49-53.
    • (1995) Anal. Biochem. , vol.225 , pp. 49-53
    • Ko's, P.1    Gorzo, G.2    Suranyi, G.3    Borbely, G.4
  • 24
    • 0032400792 scopus 로고    scopus 로고
    • Microcystin uptake inhibits growth and protein phosphatase activity in mustard (Sinapis alba L.) seedlings
    • Kurki-Helasmo K., Meriluoto J. Microcystin uptake inhibits growth and protein phosphatase activity in mustard (Sinapis alba L.) seedlings. Toxicon 1998, 36:1921-1926.
    • (1998) Toxicon , vol.36 , pp. 1921-1926
    • Kurki-Helasmo, K.1    Meriluoto, J.2
  • 25
    • 0034992587 scopus 로고    scopus 로고
    • Investigations into the inhibitory effects of microcystins on plant growth, and the toxicity of plant tissues following exposure
    • McElhiney J., Lawton L.A., Leifert C. Investigations into the inhibitory effects of microcystins on plant growth, and the toxicity of plant tissues following exposure. Toxicon 2001, 39:1411-1420.
    • (2001) Toxicon , vol.39 , pp. 1411-1420
    • McElhiney, J.1    Lawton, L.A.2    Leifert, C.3
  • 26
    • 70350536286 scopus 로고    scopus 로고
    • Microcystins in groundwater wells and their accumulation in vegetable plants irrigated with contaminated water in Saudi Arabia
    • Mohamed Z.A., Al Shehri A.M. Microcystins in groundwater wells and their accumulation in vegetable plants irrigated with contaminated water in Saudi Arabia. Hazardous Mater. 2009, 172:310-315.
    • (2009) Hazardous Mater. , vol.172 , pp. 310-315
    • Mohamed, Z.A.1    Al Shehri, A.M.2
  • 27
    • 58549120394 scopus 로고    scopus 로고
    • Identification and quantification of microcystins from a Nostoc muscorum bloom occurring in Oukaïmeden River (High-Atlas mountains of Marrakech, Morocco), Environ. Monit. Assessment Doi:10.1007/s10661-008-0220-y.
    • Oudra, B., Dadi-El Andaloussi, M., Vasconcelos, V., 2008. Identification and quantification of microcystins from a Nostoc muscorum bloom occurring in Oukaïmeden River (High-Atlas mountains of Marrakech, Morocco), Environ. Monit. Assessment Doi:10.1007/s10661-008-0220-y.
    • (2008)
    • Oudra, B.1    Dadi-El Andaloussi, M.2    Vasconcelos, V.3
  • 29
    • 0031680735 scopus 로고    scopus 로고
    • Etude expérimentale de l'effet de Synechocystis sp. (picocyanobactérie) sur le comportement de certaines bactéries d'intérĉt sanitaire
    • Oufdou K., Mezrioui N., Oudra B., Ouhdouch Y. Etude expérimentale de l'effet de Synechocystis sp. (picocyanobactérie) sur le comportement de certaines bactéries d'intérĉt sanitaire. Int. J. Limnol. 1998, 34:259-268.
    • (1998) Int. J. Limnol. , vol.34 , pp. 259-268
    • Oufdou, K.1    Mezrioui, N.2    Oudra, B.3    Ouhdouch, Y.4
  • 30
    • 34547148580 scopus 로고    scopus 로고
    • Uptake of microcystins-LR and -LF (cyanobacterial toxins) in seedlings of several important agricultural plant species and the correlation with cellular damage (lipid peroxidation)
    • Peuthert A., Chakrabarti S., Pflugmacher S. Uptake of microcystins-LR and -LF (cyanobacterial toxins) in seedlings of several important agricultural plant species and the correlation with cellular damage (lipid peroxidation). Environ. Toxicol. 2007, 22:436-442.
    • (2007) Environ. Toxicol. , vol.22 , pp. 436-442
    • Peuthert, A.1    Chakrabarti, S.2    Pflugmacher, S.3
  • 31
    • 67349158617 scopus 로고    scopus 로고
    • Comparison of sensitivity of grasses (Lolium perenne L. and Festuca rubra L.) and Lettuce (Lactuca sativa) exposed to water contaminated with microcystins
    • Pereira S., Saker M.L., Vale M., Vasconcelos V.M. Comparison of sensitivity of grasses (Lolium perenne L. and Festuca rubra L.) and Lettuce (Lactuca sativa) exposed to water contaminated with microcystins. Bull. Environ. Contam. Toxicol. 2009, 83:81-84.
    • (2009) Bull. Environ. Contam. Toxicol. , vol.83 , pp. 81-84
    • Pereira, S.1    Saker, M.L.2    Vale, M.3    Vasconcelos, V.M.4
  • 32
    • 0036045296 scopus 로고    scopus 로고
    • Possible allelopathic effects of cyanotoxins, with reference to microcystin-LR, in aquatic ecosystems
    • Pflugmacher S. Possible allelopathic effects of cyanotoxins, with reference to microcystin-LR, in aquatic ecosystems. Environ. Toxicol. 2002, 17:407-413.
    • (2002) Environ. Toxicol. , vol.17 , pp. 407-413
    • Pflugmacher, S.1
  • 33
    • 33750583339 scopus 로고    scopus 로고
    • Effects of cyanobacterial toxins and cyanobacterial cell-free crude extract on germination of alfalfa (Medicago sativa) and induction of oxidative stress
    • Pflugmacher S., Jung K., Lundvall L., Neumann S., Peuthert A. Effects of cyanobacterial toxins and cyanobacterial cell-free crude extract on germination of alfalfa (Medicago sativa) and induction of oxidative stress. Environ. Toxicol. Chem. 2006, 25:2381-2387.
    • (2006) Environ. Toxicol. Chem. , vol.25 , pp. 2381-2387
    • Pflugmacher, S.1    Jung, K.2    Lundvall, L.3    Neumann, S.4    Peuthert, A.5
  • 34
    • 79951949026 scopus 로고    scopus 로고
    • Identification of an enzymatically formed glutathione conjugate of the cyanobacterial hepa growth and protein phosphatase activity in mustard (Sinapis alba L.) seedlings
    • Pflugmacher S., Wiegand C., Oberemm A., Beattie K.A., Krause E., Codd G.A., Steinberg C.E.W. Identification of an enzymatically formed glutathione conjugate of the cyanobacterial hepa growth and protein phosphatase activity in mustard (Sinapis alba L.) seedlings. Toxicon 1998, 36:1921-1926.
    • (1998) Toxicon , vol.36 , pp. 1921-1926
    • Pflugmacher, S.1    Wiegand, C.2    Oberemm, A.3    Beattie, K.A.4    Krause, E.5    Codd, G.A.6    Steinberg, C.E.W.7
  • 35
    • 34447558196 scopus 로고    scopus 로고
    • Influence of a cyanobacterial crude extract containing microcystin-LR on the physiology and antioxidative defence systems of different spinach variants
    • Pflugmacher S., Aulhorn M., Grimm B. Influence of a cyanobacterial crude extract containing microcystin-LR on the physiology and antioxidative defence systems of different spinach variants. New Phytol. 2007, 175:482-489.
    • (2007) New Phytol. , vol.175 , pp. 482-489
    • Pflugmacher, S.1    Aulhorn, M.2    Grimm, B.3
  • 36
    • 0035040327 scopus 로고    scopus 로고
    • Cyanobacterial toxins and endotoxins their origin and their ecophysiological effects in aquatic organisms
    • Pflugmacher S., Ame M.V., Wiegand C., Steinberg C.E. Cyanobacterial toxins and endotoxins their origin and their ecophysiological effects in aquatic organisms. Wasser Boden 2001, 53:15-20.
    • (2001) Wasser Boden , vol.53 , pp. 15-20
    • Pflugmacher, S.1    Ame, M.V.2    Wiegand, C.3    Steinberg, C.E.4
  • 37
    • 0035198489 scopus 로고    scopus 로고
    • The effects of cyanobacterial crude extract on different aquatic organisms: evidence for cyanobacterial toxin modulating factors
    • Pietsch C., Weigand C., Ame M.V., Nicklisch A., Wunderlin D., Pflugmacher S. The effects of cyanobacterial crude extract on different aquatic organisms: evidence for cyanobacterial toxin modulating factors. Environ. Toxicol. 2001, 16:535-542.
    • (2001) Environ. Toxicol. , vol.16 , pp. 535-542
    • Pietsch, C.1    Weigand, C.2    Ame, M.V.3    Nicklisch, A.4    Wunderlin, D.5    Pflugmacher, S.6
  • 38
    • 0034973677 scopus 로고    scopus 로고
    • Dissecting the superoxide dismutase-ascorbate-glutathione pathway in chloroplasts by metabolic modelling. Computer simulations as a step towards flux analysis
    • Polle A. Dissecting the superoxide dismutase-ascorbate-glutathione pathway in chloroplasts by metabolic modelling. Computer simulations as a step towards flux analysis. Plant Physiol. 2001, 126:445-462.
    • (2001) Plant Physiol. , vol.126 , pp. 445-462
    • Polle, A.1
  • 40
    • 46049099594 scopus 로고    scopus 로고
    • Effects of cyanobacteria producing microcystins on seed germination and seedling growth of several agricultural plants
    • Saqrane S., El Ghazali I., Oudra B., Bouarab L., Vasconcelos V. Effects of cyanobacteria producing microcystins on seed germination and seedling growth of several agricultural plants. Environ. Sci. Health B 2008, 43:443-451.
    • (2008) Environ. Sci. Health B , vol.43 , pp. 443-451
    • Saqrane, S.1    El Ghazali, I.2    Oudra, B.3    Bouarab, L.4    Vasconcelos, V.5
  • 41
    • 67349238231 scopus 로고    scopus 로고
    • Physiological changes in triticum durum, zea mays, pisum sativum and lens esculenta cultivars, caused by irrigation with water contaminated with microcystins: a laboratory experimental approach
    • Saqrane S., Ouahid Y., El Ghazali I., Oudra B., Bouarab L., del Campo F.F. Physiological changes in triticum durum, zea mays, pisum sativum and lens esculenta cultivars, caused by irrigation with water contaminated with microcystins: a laboratory experimental approach. Toxicon 2009, 53:786-796.
    • (2009) Toxicon , vol.53 , pp. 786-796
    • Saqrane, S.1    Ouahid, Y.2    El Ghazali, I.3    Oudra, B.4    Bouarab, L.5    del Campo, F.F.6
  • 42
    • 0027323054 scopus 로고
    • Protein phosphatase activity is required for light inducible gene expression in maize
    • Sheen J. Protein phosphatase activity is required for light inducible gene expression in maize. EMBO J. 1993, 12:3497-3505.
    • (1993) EMBO J. , vol.12 , pp. 3497-3505
    • Sheen, J.1
  • 44
    • 0028047087 scopus 로고
    • Inhibitors of protein phosphatases 1 and 2A block the sugar-inducible gene expression in plants
    • Takeda S., Mano S., Ohto M., Nakamura K. Inhibitors of protein phosphatases 1 and 2A block the sugar-inducible gene expression in plants. Plant Physiol. 1994, 106:567-574.
    • (1994) Plant Physiol. , vol.106 , pp. 567-574
    • Takeda, S.1    Mano, S.2    Ohto, M.3    Nakamura, K.4
  • 45
    • 34247140207 scopus 로고    scopus 로고
    • Effects of living cyanobacteria, cyanobacterial extracts and pure microcystins on growth and ultrastructure of microalgae and bacteria
    • Valdor R., Aboal M. Effects of living cyanobacteria, cyanobacterial extracts and pure microcystins on growth and ultrastructure of microalgae and bacteria. Toxicon 2007, 49:769-779.
    • (2007) Toxicon , vol.49 , pp. 769-779
    • Valdor, R.1    Aboal, M.2
  • 47
    • 20444503368 scopus 로고    scopus 로고
    • Microcystin-RR uptake and its effects on the growth of submerged macrophyte Vallisneria natans (lour.) hara
    • Yin L., Huang J., Li D., Liu Y. Microcystin-RR uptake and its effects on the growth of submerged macrophyte Vallisneria natans (lour.) hara. Environ. Toxicol. 2005, 20:308-313.
    • (2005) Environ. Toxicol. , vol.20 , pp. 308-313
    • Yin, L.1    Huang, J.2    Li, D.3    Liu, Y.4
  • 48
    • 0035675426 scopus 로고    scopus 로고
    • Taxonomy of rhizobia
    • Zakhia F., De Lajudie P. Taxonomy of rhizobia. Agronomie 2001, 21:569-576.
    • (2001) Agronomie , vol.21 , pp. 569-576
    • Zakhia, F.1    De Lajudie, P.2
  • 49
    • 11244346943 scopus 로고    scopus 로고
    • Hepatotoxic cyanobacteria: a review of the biological importance of microcystins in freshwater environments
    • Zurawell R.W., Chen H., Burke J.M., Prepas E.E. Hepatotoxic cyanobacteria: a review of the biological importance of microcystins in freshwater environments. Toxicol. Environ. Health B 2005, 8:1-37.
    • (2005) Toxicol. Environ. Health B , vol.8 , pp. 1-37
    • Zurawell, R.W.1    Chen, H.2    Burke, J.M.3    Prepas, E.E.4


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.