Egyptian Society of Biological SciencesEgyptian Academic Journal of Biological Sciences, G. Microbiology2090-08725220131201Biological control of Helminthosporium sativum the causal agent of root rot in wheat by some antagonistic fungi191663410.21608/eajbsg.2013.16634ENSarhan Abdul RidhaTahaDepartment of Dentistry, Microbiology Branch, University College of Humanities, Najaf, IraqJournal Article20181014The present study has been undertaken to<br />determine the efficacy of some antagonistic fungi isolated from the rhizosphere<br />of wheat plants grown in Summer region, Diwaniya Governorate, Mid Iraq for the<br />biological control of <em>Helminthosporium sativum</em>, the causal organism of<br />root rot disease of wheat <em>in vitro</em>. Three different species from the<br />genus <em>Trichoderma</em>: <em>T. harzianum, T. pseudokoningii and T. lignorum</em>,<br />in addition to <em>Stachybotrys atra</em> and <em>Penicillium</em> sp. were<br />isolated from the rhizosphere of wheat plants. Laboratory experiments indicated<br />that <em>T. harzianum </em>and<em> S. atra</em><br />were highly antagonistic to the pathogen when grown together on potato dextrose<br />agar in Petri plates. Microscopic examination of the mycelia showed that hyphae<br />of <em>T. harzianum</em> were parasitized<em> H. sativum</em>, coiled around its<br />hyphae and caused its lysis, but did not penetrate inside the hyphae. However, <em>S.<br />atra</em> was invaded colonies of <em>H. sativum</em> and caused severe hyphal<br />damage. In the experiments of culture filtrates of the antagonistic fungi, <em>T.<br />harzianum and S. atra, </em>were able to suppress growth of <em>H. sativum</em>,<br />if incorporated in the medium and proved to be effective in controlling the<br />pathogen. Results<br />of effect of filtrate on spore germination showed that about 80 and 95% of them<br />are unable to germinate with high concentrations (15 or 20 %) of culture<br />filtrates of<em> T. harzianum</em> and<em> S. atra </em>respectively. However, the<br />other antagonists:<em> T. pseudokoningii, T. lignorum </em>and<em> Penicillium</em><br />sp. were less effective in inhibiting spore germination of the pathogen. Results<br />of antagonistic effect of the culture filtrates on wheat seed infection, except<br /><em>T. lignorum</em>, showed that seed colonization by the root rot fungus was<br />decreased significantly at the concentrations of 15 and 20 % compared with<br />control. Seed coating with antagonistic fungi was the best biological seed<br />treatment for reducing seed rot and diseased seedling caused by <em>H. sativum</em>.<br />Antagonistic fungi have no side effects on seed germination except <em>Penicillium</em><br />sp. which reduced the seed activity and germination as compared with the other<br />antagonists and with the control. It can be concluded that <em>T. harzianum</em><br />is a strong mycoparasite and <em>S. atra</em> is a good antagonistic agent to<br />control <em>H. sativum</em>, but in fields may be their activity are conditioned<br />by soil environment specially the microfloraEgyptian Society of Biological SciencesEgyptian Academic Journal of Biological Sciences, G. Microbiology2090-08725220131201Probiotic stability of yoghurts during refrigerated storage9191663510.21608/eajbsg.2013.16635ENAli F.S.Department of Agricultural Microbiology, Faculty of Agriculture - Minia Univ. Minia EgyptSaad O. A.O.Department of Agricultural Microbiology, Faculty of Agriculture - Minia Univ. Minia EgyptSalwa A .G.HusseinDepartment of Agricultural Microbiology, Faculty of Agriculture - Minia Univ. Minia EgyptJournal Article20181014 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 <em>Bifidobacterium spp</em> (RC1 b8, RC4 b2, FC1b1, SC1 a4, LZ1b8 and LZ1a7)and <em>Lactobacillus </em>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.Egyptian Society of Biological SciencesEgyptian Academic Journal of Biological Sciences, G. Microbiology2090-08725220131201Antimicrobial activity of probiotic bacteria21341663610.21608/eajbsg.2013.16636ENAli F.S.Department of Agricultural Microbiology - Faculty of Agriculture, Minia University- Minia EgyptSaad O. A.O.Department of Agricultural Microbiology - Faculty of Agriculture, Minia University- Minia EgyptSalwa A.HusseinDepartment of Agricultural Microbiology - Faculty of Agriculture, Minia University- Minia EgyptJournal Article20181014Probiotic 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 <em>Lactobacillus spp</em> (S4b1 and S2a3), eleven <em>Bifidobacterium </em>spp. (RC1 b8, RC2 b1, SC1a4, RC4b2, FC1b1, RC2b4, RC4a3, LZ1a3 and LZa7) and one <em>Streptoococcus </em>spp. (RC2b3), were used against several human <em>(Staphyllococcus aureus</em>. and <em>Eschericia coli</em>) and plant (<em>Rhizoctonia solani </em>and<em> Fusarium oxysporum</em>) 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<em> Staphyllococcus aureus</em>. 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<em> Eschericia coli</em> was almost similar to that obtained against <em>S. aureus</em>, 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 <em>E. coli</em> was slightly less as compared to that obtained against<em> S. aureus.</em>
The antifungal activity of the same14 probiotic isolates was tested against the plant pathogenic <em>Rhizoctonia solani </em>and <em>Fusarium oxysporum</em>. 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 <em>R. solani </em>were RC4b2 (52.3 % GI), followed by both RC4b3 and RC1b8 (47.6 % GI). Also, the most active isolate against <em>F. oxysporum </em>was Y2a5 (51.2 GI).Egyptian Society of Biological SciencesEgyptian Academic Journal of Biological Sciences, G. Microbiology2090-08725220131201Purification of hemolysin from Aspergillus fumigatus and study its cytotoxic effect on normal cell line (REF) in vitro35431663710.21608/eajbsg.2013.16637ENBatool OmranTheebDepartment of Biology, Iraqia UniversityFarooq IbrahemMohammadBiotechnology Research Center, Al- Nahrain UniversityAbdulkareem JasimHashimDepartment of Biotechnology, College of science, Baghdad University. Baghdad-IraqSumia SamiHashimDepartment of Biotechnology, College of science, Baghdad University. Baghdad-IraqJournal Article20181014<em>Aspergillus fumigtus </em>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.
<strong> </strong>Egyptian Society of Biological SciencesEgyptian Academic Journal of Biological Sciences, G. Microbiology2090-08725220131201Impact of zinc and lead on soil respiration and microbial content under in vitro conditions45501663810.21608/eajbsg.2013.16638ENAbdousalam AhmedAlgaidiFaculty of Agriculture, Sebha University, LibyaJournal Article20181014The 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 CO<sub>2</sub>-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 CO<sub>2</sub>-production at different incubation intervals. The strongest inhibition of the gas production was detected by the influence of Zinc ions.