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Search Results: 1 - 10 of 4031 matches for " secondary metabolites "
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Nutritional Status and Total Phenols of Passiflora Genotypes Related to Nitrogen Fertilization  [PDF]
Renata Vianna Lima, Almy Junior Cordeiro de Carvalho, Paulo Cesar Santos, Jalille Amim Altoé Freitas, Mírian Peixoto Soares da Silva, Silvio de Jesus Freitas, Marta Simone Mendon?a Freitas
American Journal of Plant Sciences (AJPS) , 2015, DOI: 10.4236/ajps.2015.65074
Abstract: This paper was developed in order to verify the influence of nitrogen fertilization and different genotypes in the nutritional aspect and in the production of total phenols in passifloraceae. The experimental design was randomized blocks in a 5 × 2 × 2 factorial scheme, being five genotypes of Passiflora (three genotypes of Passiflora edulis, a genotype of Passiflora alata and a genotype of Passiflora ligularis), two levels of cow manure (with and without) and two doses of N (20 and 80 g), with four replicates. At 120 days after sowing, levels of foliar nutrient and total phenols were determined. Foliar N content varied depending on N doses, organic fertilization and the genotypes used. Foliar levels of P and K were higher when all genotypes received organic fertilization, while the levels of Fe and Mn were similar regardless of this fertilization. The levels of Ca and Mg were higher related to organic fertilization and the genotypes, in isolation. But the foliar contents of S, Zn and Cu increased only in relation to the used genotypes, and the average foliar content of total phenols found was 19.4 g·kg-1, ranging from 13.1 to 23.2 g·kg-1, being the lowest value observed in Passiflora alata without fertilization with cow manure. It is concluded that the nutritional requirement for N is greater for genotypes of the species Passiflora edulis in relation to the species Passiflora alata and Passiflora ligulares, and that the organic fertilization influences positively in the production of total phenols only for the genotype of sweet passion fruit.
Impact of the Glucosinolate Sinigrin on Bacterial Communities in Pieris rapae  [PDF]
Leslie M. McKinnon, Courtney J. Robinson
Advances in Microbiology (AiM) , 2016, DOI: 10.4236/aim.2016.68057
Abstract: Dynamics in animal-associated microbiota can be difficult to study due to community complexity. Previous work showed that microbial communities in the midguts of Pieris rapae larvae contain relatively few members. In this study, we used P. rapae to test hypotheses related to how diet impacts gastrointestinal microbiota. More specifically, we investigated how the concentration of sinigrin, a glucosinolate in the natural diet of this insect, alters microbial community structure. Larvae were fed either sterile wheat germ diet alone or amended with 3.0 mg/ml, 6.0 mg/ml, or 9.0 mg/ml of sinigrin. In order to determine shifts in the gut microbial community, 16S rRNA genes from midguts were subjected to pyrosequencing and analyzed. Sinigrin had a significant impact on microbial communities in fourth instar P. rapae larvae, but this was dependent on concentration. The predominant phyla in all treatment groups were Proteobacteria and Firmicutes. Significant difference in beta diversity was typically observed when sinigrin 6 mg/ml and the control treatment groups were compared. The impact of sinigrin on the structure of the midgut microbiota is dependent on concentration, but not in a linear fashion. This may indicate that types and concentrations of glucosinolates have varied impact on midgut microbial community.
Why antibiotics: A comparative evaluation of different hypotheses for the natural role of antibiotics and an evolutionary synthesis  [PDF]
Charushila Kumbhar, Milind Watve
Natural Science (NS) , 2013, DOI: 10.4236/ns.2013.54A005

Although secondary metabolites with antimicrobial and other bioactivities are explored extensively, the natural or ecological role(s) of secondary metabolites is not yet clearly known. We review here the different hypotheses for the ecological role of antibiotics, with particular focus on the genus Streptomyces which is unparalleled in the richness of secondary metabolites. We first lay down our expectations from an ecological hypothesis for antibiotics and then weigh the six predominant hypotheses against them including antibiotics as weapons in competition, as aid in sporulation, as bartered benefits in symbioses, as signal molecules in community homeostasis, as weapons in predation and as metabolic waste or bi-products. The analysis shows that no single hypothesis meets all the expectations. While the waste or bi-product hypothesis can safely be eliminated all others have some evidence in support. It is possible therefore that antibiotics serve a multitude of ecological functions and it is possible to visualize a pathway for the radiating functions. According to this synthesis antibiotics evolved primarily as weapons in predation on other microorganisms. The inevitable co-evolution with prey species led to diversification of the genes and pathways. Some of the secondary metabolites eventually radiated to acquire other functions such as competition between predators. Some secondary metabolites evolved animal toxicity as a mutualistic barter to protect the symbiotic partner from grazing/predation by animals. Transcription modulation primarily evolved as activation of defense mechanisms by the prey which may have later radiated to serve interspecies signaling functions. The synthesis successfully links different functions of antibiotics with logical coherence.

Exploration of Activated Pathways for Improving Antifungal Agent FR901469 Productivity in Fungal Species No.11243 Using Comprehensive Pathway Model  [PDF]
Itaru Takeda, Hiroya Itoh, Makoto Matsui, Takashi Shibata, Masayuki Machida, Sachiyo Aburatani
Journal of Biosciences and Medicines (JBM) , 2017, DOI: 10.4236/jbm.2017.57003
Abstract: Secondary metabolites are important for various industrial applications. The production of secondary metabolites is often improved by the activation of substrate supply pathways for biosynthesis. However, many important pathways have remained unclear. In this study, we explored possible pathways related to substrate supply for the biosynthesis of the antifungal agent FR901469 which is a nonribosomal peptide and a fungal secondary metabolite. To clarify the unknown activated pathways, we utilized the Comprehensive Pathway Model (CPM) which was developed in our previous study. We verified that the overexpression of the hypothetical beta-alanine-aminotransferase (BAL-AT), which was included in the explored pathways, improved the FR901469 productivity. The genes encoding the BAL metabolic enzymes are considered to be important for improving the FR901469 productivity.
Streptomycetes antagonism against Cladosporium fulvum Cooke and Fusarium oxysporium f.sp. lycopersici
Soares, Ana Cristina Fermino;Sousa, Carla da Silva;Garrido, Marlon da Silva;
Ciência Rural , 2009, DOI: 10.1590/S0103-84782009005000117
Abstract: this research aimed to evaluate the secondary effects of secondary metabolites produced by streptomycetes on spore germination and mycelial growth of the phytopathogenic fungi cladosporium fulvum cooke and fusarium oxysporium f. sp. lycopersici from tomato plants. metabolites produced by streptomycete isolates codified as ac-147 and ac-92 caused 94.1% inhibition of c. fulvum while ac-95 isolate caused 33.9% inhibition. ac-92 was the most efficient for f. oxysporum f. sp. lycopersici, causing 94.2% inhibition of spore germination. for mycelial growth, ac-26 and ac-92 were the most efficient in inhibiting c. fulvum growth by 46.6% and f. oxysporum f. sp. lycopersici by 29.9%. these streptomycetes are potential agents for biocontrol development methods of these tomato plant pathogenic fungi.
Guzmán Avenda?o,Antonio J.; Barrera Adame,Diana A.;
Colombia Forestal , 2011,
Abstract: this research focused on the phytochemical characterization of the species smallanthus pyramidalis (triana) h. rob. in order to identify the secondary metabolites of flowers and leaves. this is due to the importance these trees on the sustainable development of the wetlands in the sabana de bogotá, and its possible application as a promising species in the use and conservation of these ecosystems. we performed preliminary chemical tests, fractionation using conventional techniques, identification of physical and chemical properties, and structural analysis using spectroscopic and spectrometric techniques, such as uv, 1h-rmn, 13c-rmn and gc-ms. we identified alkane-type compounds, steroids, terpenoids and flavonoids mainly, and their role in the plant and the ecosystem.
Calogênese em Cissus sicyoides L. a partir de segmentos foliares visando à produ??o de metabólitos in vitro
Rodrigues, F.R.;Almeida, W.A.B.;
Revista Brasileira de Plantas Medicinais , 2010, DOI: 10.1590/S1516-05722010000300011
Abstract: secondary metabolites are essentially produced and extracted from plants grown in the field under influence of seasonal variations. the use of biotechnological techniques is an alternative resource for drug production. among these techniques, tissue culture through callus genesis is highlighted, since callus growth is desirable to induce somaclonal variation and physiological studies, especially when the presence of secondary metabolites can be related to cell growth. the aim of this work was to establish a protocol for cissus sicyoides l. callus genesis from leaf segments in order to produce metabolites in vitro. thus, leaf segments removed from adult plants grown in the field were used as explants. after disinfestation, the material was inoculated into mt medium + 1.0 mg l-1 naa and kept in a bod chamber, with controlled temperature and luminosity. after 30 days, the percentage of surviving explants and the percentage of contamination were evaluated. for culture, mt medium + 1.0 mg l-1 naa was used, varying bap concentrations: 2.0, 4.0, 6.0 and 12.0 mg l-1. in the cultivation, the number of compact and friable calluses was counted. for the first and second subculture, the material was introduced into mt medium + 1.0 mg l-1 naa, varying the same bap concentrations; the number of friable calluses formed and the size of callus mass were described. the number of replicates formed during subcultures, and fresh and dry matter (g) were also obtained. then, phytochemical tests were done in order to identify some compounds. the adopted time and concentration of sodium hypochlorite proved to be inefficient for disinfestation. for cissus sicyoides l. callus genesis from leaf segments, the addition of 6.0 mg l-1 bap to the culture medium is needed. cardiotonic heterosides were detected in cissus sicyoides l. calluses.
Presencia de hongos fitopatógenos en frutas y hortalizas y su relación en la seguridad alimentaria
Trigos, ángel;Ramírez, Karina;Salinas, Alejandro;
Revista mexicana de micología , 2008,
Abstract: a monthly monitoring was realized during one year in fruits and vegetables expended in the city of xalapa, veracruz, méxico, in order to determine the presence of plant pathogenic fungi, as well as to determine their pathogenicity and their synthetic potential in the production of secondary metabolites toxins. twenty seven fungal species were obtained, belonging to 18 genus. of them, 100 % showed pathogenicity in the original product, and that behavior was verified throught koch's postulates. however, both sellers and consumers did not realized of that pathogenicity. literature research indicates that 60.9 % of the obtained species can be potentially producers of mycotoxins. for these reasons, it is necessary to highlight the urgency of establishing controls throught out the development of normativity which links phytosanitary diagnosis criteria with safety food in méxico.
Effect of light intensity and growth substratum on plant development and production of secondary metabolites in Cordia curassavica (Jacq.) Roem. & Schult
Paulilo, Maria Terezinha Silveira;Lapa, Flávia Sim?o;Falkenberg, Miriam de Barcellos;
Revista árvore , 2010, DOI: 10.1590/S0100-67622010000300005
Abstract: cordia curassavica (jacq.) roem. & schult. (boraginaceae), also referred to as cordia verbenacea dc, has been traditionally used for medicinal purposes. this study was driven to verify the behavior of the species in similar conditions to its natural environment, such as high light intensity and sandbank soil, and in conditions of low light intensity and fertilized substratum (dystroferric red nitosoil plus earthworm humus). the growth of the plant, the income of leaf crude extracts and, in the alcoholic extract, the number of substances found in thin layer cromatography and the toxicity of the substratum was observed. the results indicated that the growth of the root biomass, stem and leaves in discharge or lower light intensity was similar, but smaller in sandbank soil than in fertilized soil. the relative income of extracts in ether of petroleum and alcohol was larger in high light intensity and fertilized substratum. the light intensity and the substratum type didn't affect the number of substances detected in the alcoholic extract or the toxicity of this extract. stains corresponding to the rosmarinic acid were only evidenced in some samples of the alcoholic extract, not allowing the verification of the effect of the treatments about its production.
Antimicrobial activity of filamentous fungi isolated from highly antibiotic-contaminated river sediment
K. Stefan Svahn,Ulf G?ransson,Hesham El-Seedi,Lars Bohlin
Infection Ecology & Epidemiology , 2012, DOI: 10.3402/iee.v2i0.11591
Abstract: Background: Filamentous fungi are well known for their production of substances with antimicrobial activities, several of which have formed the basis for the development of new clinically important antimicrobial agents. Recently, environments polluted with extraordinarily high levels of antibiotics have been documented, leading to strong selection pressure on local sentinel bacterial communities. In such microbial ecosystems, where multidrug-resistant bacteria are likely to thrive, it is possible that certain fungal antibiotics have become less efficient, thus encouraging alternative strategies for fungi to compete with bacteria. Methods: In this study, sediment of a highly antibiotic-contaminated Indian river was sampled in order to investigate the presence of cultivable filamentous fungi and their ability to produce substances with antimicrobial activity. Results: Sixty one strains of filamentous fungi, predominantly various Aspergillus spp. were identified. The majority of the Aspergillus strains displayed antimicrobial activity against methicillin-resistant Staphylococcus aureus, extended-spectrum beta-lactamase-producing Escherichia coli, vancomycin-resistant Enterococcus faecalis and Candida albicans. Bioassay-guided isolation of the secondary metabolites of A. fumigatus led to the identification of gliotoxin. Conclusion: This study demonstrated proof of principle of using bioassay-guided isolation for finding bioactive molecules.
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