2024-03-29T03:08:18Z
https://eajbsg.journals.ekb.eg/?_action=export&rf=summon&issue=3533
Egyptian Academic Journal of Biological Sciences, G. Microbiology
2090-0872
2090-0872
2013
5
2
Biological control of Helminthosporium sativum the causal agent of root rot in wheat by some antagonistic fungi
Sarhan
Taha
The present study has been undertaken todetermine the efficacy of some antagonistic fungi isolated from the rhizosphereof wheat plants grown in Summer region, Diwaniya Governorate, Mid Iraq for thebiological control of Helminthosporium sativum, the causal organism ofroot rot disease of wheat in vitro. Three different species from thegenus Trichoderma: T. harzianum, T. pseudokoningii and T. lignorum,in addition to Stachybotrys atra and Penicillium sp. wereisolated from the rhizosphere of wheat plants. Laboratory experiments indicatedthat T. harzianum and S. atrawere highly antagonistic to the pathogen when grown together on potato dextroseagar in Petri plates. Microscopic examination of the mycelia showed that hyphaeof T. harzianum were parasitized H. sativum, coiled around itshyphae and caused its lysis, but did not penetrate inside the hyphae. However, S.atra was invaded colonies of H. sativum and caused severe hyphaldamage. In the experiments of culture filtrates of the antagonistic fungi, T.harzianum and S. atra, were able to suppress growth of H. sativum,if incorporated in the medium and proved to be effective in controlling thepathogen. Resultsof effect of filtrate on spore germination showed that about 80 and 95% of themare unable to germinate with high concentrations (15 or 20 %) of culturefiltrates of T. harzianum and S. atra respectively. However, theother antagonists: T. pseudokoningii, T. lignorum and Penicilliumsp. were less effective in inhibiting spore germination of the pathogen. Resultsof antagonistic effect of the culture filtrates on wheat seed infection, exceptT. lignorum, showed that seed colonization by the root rot fungus wasdecreased significantly at the concentrations of 15 and 20 % compared withcontrol. Seed coating with antagonistic fungi was the best biological seedtreatment for reducing seed rot and diseased seedling caused by H. sativum.Antagonistic fungi have no side effects on seed germination except Penicilliumsp. which reduced the seed activity and germination as compared with the otherantagonists and with the control. It can be concluded that T. harzianumis a strong mycoparasite and S. atra is a good antagonistic agent tocontrol H. sativum, but in fields may be their activity are conditionedby soil environment specially the microflora
biological control
Helminthosporium sativum
fungi
2013
12
01
1
9
https://eajbsg.journals.ekb.eg/article_16634_c0f6828dcf7156a2a30027ad880de8b5.pdf
Egyptian Academic Journal of Biological Sciences, G. Microbiology
2090-0872
2090-0872
2013
5
2
Probiotic stability of yoghurts during refrigerated storage
Ali
S.
Saad
O.
Salwa
Hussein
Probiotic strains were isolated from the cheese, turkey and dimity and fermented products (rayb, zeer milk,kariesh cheese), screened for clotting time of skim milk. The seven effective isolates which clotting skim milk were identified as Bifidobacterium spp (RC1 b8, RC4 b2, FC1b1, SC1 a4, LZ1b8 and LZ1a7)and Lactobacillus spp (S4b1).
The seven effective strains of probiotic bacteria were used in the production of probiotic yoghurt 100%, yoghurt of 50% probiotic bacteria with 50% yoghurt bacteria and compared with the normal yoghurt with 100% normal yoghurt bacteria. The changes in pH, stability of bacteria, and physical properties in probiotic yoghurt 100%, yoghurt of 50% probiotic bacteria with 50% yoghurt bacteria and the normal yoghurt with 100% normal yoghurt bacteria during product’s shelf life at 4C for four weaks were also studied.
probiotic
yoghurt
antagonism and stability
2013
12
01
9
19
https://eajbsg.journals.ekb.eg/article_16635_bf6f52dd6cf390714788c80d01c36a6f.pdf
Egyptian Academic Journal of Biological Sciences, G. Microbiology
2090-0872
2090-0872
2013
5
2
Antimicrobial activity of probiotic bacteria
Ali
S.
Saad
O.
Salwa
Hussein
Probiotic strains were isolated from different cheeses (turkey and domiatii and cottage and kariesh cheese) and fermented products (yoghurt, raib, zeer milk and kishk). The isolates were screened for rate of growth increase in MSR broth at pH 3, pH4, acid production after 48 hours and degree of bile salt (0.3%) tolerance, strength of adhesion and clotting time (3 to 48 hrs) of skim milk. The good fourteen isolates identified as two Lactobacillus spp (S4b1 and S2a3), eleven Bifidobacterium spp. (RC1 b8, RC2 b1, SC1a4, RC4b2, FC1b1, RC2b4, RC4a3, LZ1a3 and LZa7) and one Streptoococcus spp. (RC2b3), were used against several human (Staphyllococcus aureus. and Eschericia coli) and plant (Rhizoctonia solani and Fusarium oxysporum) pathogens by examining their in vitro antimicrobial properties.
Antibacterial activity of the good fourteen selected probiotic isolates in this test exhibited varying degrees of inhibitory activity against human pathogenic Staphyllococcus aureus. The isolates LZb8, S4b1 and RC2b3 exhibited the superior antibacterial activity with inhibition zones (I.Z.) ranged 8.3 - 8.4 mm followed by the isolates Kb2, LZa7 and Y2a5. The least activity was recorded for the isolates SCa4 and RC4b2 (I.Z.) ranged 2.3-2.5 mm. The antibacterial activity of the same probiotic isolates against human pathogenic Eschericia coli was almost similar to that obtained against S. aureus, and followed the same pattern. The isolates LZb8, S4b1 and RC2b3 possessed the highest activity, while the isolates SCa4 and RC4b2 were highly significantly the least active. It seems that the inhibitory activity of the isolates against E. coli was slightly less as compared to that obtained against S. aureus.
The antifungal activity of the same14 probiotic isolates was tested against the plant pathogenic Rhizoctonia solani and Fusarium oxysporum. All probiotic isolates were highly significantly active on both fungi as compared to the control, showing % growth inhibition (%GI) ranges of 26.7-52.3 %, and 17.1 -51.2 % against the first and the latter fungi, respectively . The most active isolates against R. solani were RC4b2 (52.3 % GI), followed by both RC4b3 and RC1b8 (47.6 % GI). Also, the most active isolate against F. oxysporum was Y2a5 (51.2 GI).
Antibacterial activity
probiotic
antifungal activity
human and plant pathogenic
2013
12
01
21
34
https://eajbsg.journals.ekb.eg/article_16636_fd76771bfada872036cad50cb3b0e0cd.pdf
Egyptian Academic Journal of Biological Sciences, G. Microbiology
2090-0872
2090-0872
2013
5
2
Purification of hemolysin from Aspergillus fumigatus and study its cytotoxic effect on normal cell line (REF) in vitro
Batool
Theeb
Farooq
Mohammad
Abdulkareem
Hashim
Sumia
Hashim
Aspergillus fumigtus produced a protenaceous hemolysin, when incubated on sheeps blood agar, from 41 isolates thirty isolates (73.1%) has able to produce hemolysin. Hemolysin purified from tryptic soy broth using ion exchang and gel filtaration and found to have amolecular weight of approximately 74.52 KD a. In this study, hemolysin was used in an experimental model to study its Cytotoxic activity by evaluating effect on REF cell line (Rat embryonic fibroblast), on exposure time of 24 hrs at three different concentrations triplicate of each concentration were used, Cytotoxicity of the purified compounds are active against REF cell line under study and a toxic effect was clear with a significant difference at the level of probability (p< 0.05) and this effect was increase gradually with the increase of hemolysin concentration.
Aspergillus fumigatus
Hemolysin
Cytotoxic activity
2013
12
01
35
43
https://eajbsg.journals.ekb.eg/article_16637_d1309646a14dfd24fd887b7ad90a005b.pdf
Egyptian Academic Journal of Biological Sciences, G. Microbiology
2090-0872
2090-0872
2013
5
2
Impact of zinc and lead on soil respiration and microbial content under in vitro conditions
Abdousalam
Algaidi
The habitation and activities of soil aerobic bacteria living in the sandy clay soil were affected by the toxicity of Zinc and Lead ions at different levels. Their inhibitory effect was manifested directly in the decrease of the total aerobic bacteria counts in the soil and physiological activity of the soil aerobic bacteria. Aerobic bacteria population generally decreased similarly to the CO2-production in response to the toxic effects of the investigated metal ions. The soil samples were metabolically activated by C,N and P in the form of sodium nitrate, potassium phosphate and glucose, respectively as substrate-induced respiration. The inhibitions of biological activities in the soil samples were appeared even after three weeks, but highly significant effects were obtained after six-week incubation period. Lead had smallest effects on decreasing CO2-production at different incubation intervals. The strongest inhibition of the gas production was detected by the influence of Zinc ions.
Heavy metals
soil aerobic bacteria-toxicity
2013
12
01
45
50
https://eajbsg.journals.ekb.eg/article_16638_52400a783cbfeccf72ea7bf435e2b48b.pdf