scholarly journals Fungitoxicidade dos extratos vegetais e do óleo essencial de Lippia gracilis Schauer sobre o fungo Monosporascus cannonballus Pollack e Uecker

2015 ◽  
Vol 41 (2) ◽  
pp. 153-155 ◽  
Author(s):  
Luciana Cristina Borges Fernandes ◽  
Cynthia Cavalcanti de Albuquerque ◽  
Rui Sales Júnior ◽  
Francisco Fábio Mesquita Oliveira ◽  
Eleneide Pinto Gurgel ◽  
...  

Alecrim da Chapada (Lippia gracilis Schauer) é considerada uma planta rica em óleo essencial e possui atividade antimicrobiana comprovada, devido aos monoterpenos fenólicos carvacrol e timol. O objetivo deste trabalho foi avaliar o efeito in vitro do óleo essencial e dos extratos etanólicos de raízes e folhas de L. gracilis no controle do fungo Monosporasccus cannonballus, causador do colapso do meloeiro. O extratos foram testados nas concentrações de 2500, 5000 e 7500 ppm e o óleo essencial de L. gracilis foi avaliado nas concentrações 255, 340 e 425 ppm tendo também um controle positivo com o fungicida comercial Captan(r) e um negativo apenas com meio BDA (batata, dextrose, ágar). Discos de micélio com 3 mm de diâmetro foram inoculados no centro de placas de Petri e as medições do crescimento micelial do fungo foram realizadas 48 horas após a montagem do experimento. Verificou-se que o óleo essencial de L. gracilis nas três concentrações testadas foi eficiente para o controle do fungo, com percentuais de inibição de 100%, em comparação ao tratamento com o controle negativo (0%) que não apresentou inibição. O extrato radicular, nas concentrações de 5000 e 7500 ppm e o extrato foliar na concentração de 7500 ppm também proporcionaram um percentual de inibição de 100%.

Plant Disease ◽  
2003 ◽  
Vol 87 (1) ◽  
pp. 45-50 ◽  
Author(s):  
M. M. Waugh ◽  
D. H. Kim ◽  
D. M. Ferrin ◽  
M. E. Stanghellini

Vine decline of melons caused by Monosporascus cannonballus is a destructive disease worldwide. Ascospores, the only spore stage produced by this soilborne fungus, serve as the primary inoculum. Ascospore production on roots occurs primarily at the end of the cropping season, and high soil temperatures (25 to 30°C) govern, in part, the rate of reproduction of the pathogen. In vitro studies confirm that the optimal temperature for reproduction ranged from 25 to 30°C. Additionally, the root system of a single mature cantaloupe plant is capable of supporting the production of approximately 400,000 ascospores. The latter population, if incorporated uniformly into 0.03 m3 (1 ft3) of soil, would be equivalent to 10 ascospores per gram of soil. Known problem fields contain as few as 2 ascospores per gram of soil. These results offer a possible explanation for field observations that economically significant disease problems can occur after only two consecutive melon crops if environmental conditions are conducive to pathogen reproduction, and they suggest that strategies to inhibit reproduction would be instrumental in disease management.


2008 ◽  
Vol 32 (5) ◽  
pp. 1387-1393 ◽  
Author(s):  
Marcelino Gevilbergue Viana ◽  
Cynthia Cavalcanti de Albuquerque ◽  
Erika Valente de Medeiros ◽  
Francisco Arnaldo Viana ◽  
Kathia Maria Barbosa e Silva

Objetivou-se, neste trabalho, avaliar in vitro a atividade dos extratos alcoólicos de Senna alata (L.) Roxb. sobre Monosporascus cannonballus. O delineamento experimental foi inteiramente casualizado com esquema fatorial 3 x 6 + 1, sendo constituído por três partes da planta (caule, raiz e vagem), por seis concentrações (0,25; 0,50; 50; 75; 250; 500 ppm ) mais a testemunha, com quatro repetições por tratamento. As variáveis avaliadas foram: taxa de crescimento micelial (TCM), inibição do crescimento micelial (ICM) e área abaixo da curva do crescimento micelial (AACCM). A concentração de 500 ppm foi a mais eficiente, nas três partes vegetais avaliadas. O porcentual de inibição na referida concentração foi de 28,60%, 36,70% e 27,99% para caule, raiz e vagem respectivamente. Diante dos resultados, observa-se que os extratos de S. alata indicam um forte potencial de controle para o fungo Monosporascus cannonballus.


2020 ◽  
Vol 69 (3) ◽  
pp. 379-383
Author(s):  
RAHIL SAID AL-BADI ◽  
THAMODINI GAYA KARUNASINGHE ◽  
ABDULLAH MOHAMMED AL-SADI ◽  
ISSA HASHIL AL-MAHMOOLI ◽  
RETHINASAMY VELAZHAHAN

Endophytic fungi viz., Nigrospora sphaerica (E1 and E6), Subramaniula cristata (E7), and Polycephalomyces sinensis (E8 and E10) were isolated from the medicinal plant, Shirazi thyme (Zataria multiflora). In in vitro tests, these endophytes inhibited the mycelial growth of Monosporascus cannonballus, a plant pathogenic fungus. Morphological abnormalities in the hyphae of M. cannonballus at the edge of the inhibition zone in dual cultures with N. sphaerica were observed. The culture filtrates of these endophytes caused leakage of electrolytes from the mycelium of M. cannonballus. To our knowledge, this is the first report on the isolation and characterization of fungal endophytes from Z. multiflora as well as their antifungal effect on M. cannonballus.


Plant Disease ◽  
1999 ◽  
Vol 83 (12) ◽  
pp. 1137-1141 ◽  
Author(s):  
R. Cohen ◽  
S. Pivonia ◽  
D. Shtienberg ◽  
M. Edelstein ◽  
D. Raz ◽  
...  

Sudden wilt (vine decline) of melon, caused by Monosporascus cannonballus, is a worldwide problem in arid and semi-arid regions. Soil disinfestation by fumigation with methyl bromide before planting is a common treatment for disease management but, because methyl bromide is expected to be banned from use within the next 10 years, alternative measures for disease suppression are needed. The efficacy of 29 fungicides against M. cannonballus was evaluated in vitro. Among the fungicides tested, fluazinam and kresoxim methyl were the most effective and both totally inhibited the growth of M. cannonballus in culture at concentrations of 10 μg a.i /ml. Because fluazinam also was effective in inhibition of Pythium aphnidermatum, which also may be involved in sudden wilt syndrome, and kresoxim methyl was not, fluazinam was chosen for further tests. The effective dose of fluazinam for M. cannonballus that reduced mycelial growth by 50% was 0.09 μg a.i./ml. Fluazinam efficacy was evaluated in three field experiments conducted in the spring and in the late summer cropping seasons. In two of the experiments, applications of fluazinam resulted in approximately 87% wilt reduction, whereas in the third experiment it was only 32%. The mobility of fluazinam in soil was determined in samples taken from the field. Fungicide mobility in soil was relatively limited; most of the compound was adsorbed to soil particles, resulting in a zone of high concentration that decreased with depth and distance from the application site. Nevertheless, rates measured even at a depth of 25 cm were sufficient to control M. cannonballus. This study shows that fluazinam may be used as one component in an integrated approach for suppression of sudden wilt of melons.


Author(s):  
P.L. Moore

Previous freeze fracture results on the intact giant, amoeba Chaos carolinensis indicated the presence of a fibrillar arrangement of filaments within the cytoplasm. A complete interpretation of the three dimensional ultrastructure of these structures, and their possible role in amoeboid movement was not possible, since comparable results could not be obtained with conventional fixation of intact amoebae. Progress in interpreting the freeze fracture images of amoebae required a more thorough understanding of the different types of filaments present in amoebae, and of the ways in which they could be organized while remaining functional.The recent development of a calcium sensitive, demembranated, amoeboid model of Chaos carolinensis has made it possible to achieve a better understanding of such functional arrangements of amoeboid filaments. In these models the motility of demembranated cytoplasm can be controlled in vitro, and the chemical conditions necessary for contractility, and cytoplasmic streaming can be investigated. It is clear from these studies that “fibrils” exist in amoeboid models, and that they are capable of contracting along their length under conditions similar to those which cause contraction in vertebrate muscles.


Author(s):  
John J. Wolosewick ◽  
John H. D. Bryan

Early in spermiogenesis the manchette is rapidly assembled in a distal direction from the nuclear-ring-densities. The association of vesicles of smooth endoplasmic reticulum (SER) and the manchette microtubules (MTS) has been reported. In the mouse, osmophilic densities at the distal ends of the manchette are the organizing centers (MTOCS), and are associated with the SER. Rapid MT assembly and the lack of rough ER suggests that there is an existing pool of MT protein. Colcemid potentiates the reaction of vinblastine with tubulin and was used in this investigation to detect this protein.


Author(s):  
E. J. Kollar

The differentiation and maintenance of many specialized epithelial structures are dependent on the underlying connective tissue stroma and on an intact basal lamina. These requirements are especially stringent in the development and maintenance of the skin and oral mucosa. The keratinization patterns of thin or thick cornified layers as well as the appearance of specialized functional derivatives such as hair and teeth can be correlated with the specific source of stroma which supports these differentiated expressions.


Author(s):  
M. Kraemer ◽  
J. Foucrier ◽  
J. Vassy ◽  
M.T. Chalumeau

Some authors using immunofluorescent techniques had already suggested that some hepatocytes are able to synthetize several plasma proteins. In vitro studies on normal cells or on cells issued of murine hepatomas raise the same conclusion. These works could be indications of an hepatocyte functionnal non-specialization, meanwhile the authors never give direct topographic proofs suitable with this hypothesis.The use of immunoenzymatic techniques after obtention of monospecific antisera had seemed to us useful to bring forward a better knowledge of this problem. We have studied three carrier proteins (transferrin = Tf, hemopexin = Hx, albumin = Alb) operating at different levels in iron metabolism by demonstrating and localizing the adult rat hepatocytes involved in their synthesis.Immunological, histological and ultrastructural methods have been described in a previous work.


Author(s):  
Ann Chidester Van Orden ◽  
John L. Chidester ◽  
Anna C. Fraker ◽  
Pei Sung

The influence of small variations in the composition on the corrosion behavior of Co-Cr-Mo alloys has been studied using scanning electron microscopy (SEM), energy dispersive x-ray analysis (EDX), and electrochemical measurements. SEM and EDX data were correlated with data from in vitro corrosion measurements involving repassivation and also potentiostatic anodic polarization measurements. Specimens studied included the four alloys shown in Table 1. Corrosion tests were conducted in Hanks' physiological saline solution which has a pH of 7.4 and was held at a temperature of 37°C. Specimens were mechanically polished to a surface finish with 0.05 µm A1203, then exposed to the solution and anodically polarized at a rate of 0.006 v/min. All voltages were measured vs. the saturated calomel electrode (s.c.e.).. Specimens had breakdown potentials near 0.47V vs. s.c.e.


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