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by
M.J. Mahdavi |
Total Records (
4 ) for
M.J. Mahdavi |
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M. Kalantar Zadeh
,
G.H. Shahidi Bonjar
,
P. Rashid Farrokhi
,
A. Ghasemi
,
S. Aghighi
and
M.J. Mahdavi
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Streptomyces scabies and S. acidiscabies, the two major phytopathogens induce potato common scab in potato growing areas of Iran. Soil Actinomycetes including 174 isolates were assayed for assessing antagonistic activity against Streptomyces scabies and S. acidiscabies. From tested isolates, S. olivaceus, strain 115 and S. plicatus, strain 101 showed high anti-scab activity revealed by bioassays in agar disk and well diffusion methods. For further biological characterizations, the active strains were grown in submerged cultures to determine growth curve and prepare crude extracts. Preliminary greenhouse studies indicated that amending soil with the S. olivaceus, strain 115 and S. plicatus strain 101 reduce crop losses due to the pathogens. Antibacterial activities of both antagonists were of bactericidal type on both pathogens with complete inhibitory effects. |
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G.H. Shahidi Bonjar
,
M.H. Fooladi
,
M.J. Mahdavi
and
A. Shahghasi
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Rapid emergence of antibacterial resistance is well documented as a serious
problem worldwide. This situation shows that the potencies of prevalent antibiotics
are decreasing steadily. This situation implies the need for searching new antimicrobials
to replace with invalidated ones or use in antibiotic rotation programs. In
a four years study, from 1,300 soil Actinomycete isolates collected from different
localities of Kerman, Hormozgan, Sistan and Baloochestan, south and south east
Provinces of Iran, Streptomyces sp. isolate No. 419 showed widest antibacterial
activity. The active principle named as Broadspectrim. It showed antibacterial
activity against wide range of G+ and G- bacteria as Bacillus anthracis,
Bacillus subtilis, Citrobacter diversus, Citrobacter freundii,
Corynebacterium diphtheriae, Enterobacter sp., Escherichia coli,
Klebsiella pneumoniae, Micrococcus luteum, Proteus vulgaris,
Proteus rettgeri, Proteus mirabilis, Proteus morganii,
Pseudomonas fluorescens, Pseudomonas aeruginosa, Pseudomonas syringae pv
syringae, Salmonella Para Typhi A, B, C, D, Salmonella typhi,
Sarcinia sp., S. marcescens, Shigella dysentery, S. flexneri,
S. sonnei, Staphylococcus aureus, Staphylococcus epidermidis,
Streptococcus pneumoniae, Vibrio cholera Eltor (INABA) and Xanthomonas
sp. but Shigella flexneri and Staphylococcus albus were resistant
to it. |
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G.H. Shahidi Bonjar
,
S. Zamanian
,
S. Aghighi
,
P. Rashid Farrokhi
,
M.J. Mahdavi
and
I. Saadoun
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Ralstonia solanacearum has worldwide economical importance because of its destructive and soil-borne nature. Clearly chemical measures have lost their attractiveness because of development of resistant strains and undesirable effects on our environment. Consequently, biological control of pathogens is gaining great importance worldwide. To investigate for proper biocontrol agents and to obtain antibacterial antagonists from Iranian soil Actinomycetes, a vast survey was performed. Over 170 isolates of soil Actinomycetes were isolated and screened among which one isolate showed high level of activity in Agar disk and Well diffusion methods against R. solanacearum. It was identified as Streptomyces coralus strain 63. High concentration of antibacterial agent was detected at 8-11th day in shake cultures. Longevity in vitro of the active crude in soluble state determined about 40 days at room temperature. In thermal inactivation point studies, active crude retained activity up to 93°C. Antibacterial activity of the antagonists found in this study highlights their importance as candidates for further investigation in biological control of tested pathogenic bacteria. |
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F. Sharifi
,
G.H. Shahidi Bonjar
,
S. Aghighi
,
P. Rashid Farrokhi
,
E. Khalesi
,
M.J. Mahdavi
and
H. Taraz
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Pythium aphanidermatum, the major phytopathogen induce damping off, root and stem rots, blights of grasses and fruit and in greenhouse cucurbits growing all areas of the world. Soil Actinomycetes including 178 isolates were assayed for assessing antagonistic activity against P.aphanidermatum. From tested isolates, 43 isolates were effective but 2 isolates strains 311 and 321 showed high anti-fungal activity revealed by bioassays in agar disk and well diffusion methods. For further biological characterizations, the active strains were grown in submerged cultures to determine growth curve and prepare crude extracts. Preliminary greenhouse studies indicated that amending soil with these strains, 311 and 321; reduce crop losses due to the pathogen. Antifungal activities of both antagonists were of fungicidal type on pathogen with complete inhibitory effects.
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