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Stenotrophomonas rhizophila a Novel Plant-Associated Bacterium With Distinguished PGPRs Properties
2023
Asmaa Elhosieny | Mona Zayed | Shawky Selim | Ayman Yassen | Norhan Abdel Aziz
Stenotrophomonas sp. is a plant-associated rhizospheric bacteria. It can enhance plant productivity. It acts as a mineral dissolution and growth promoter for plants under salt-stress conditions. The selected isolates revealed the general morphological and biochemical characteristics of Stenotrophomonas sp. All the isolates exhibited the highest growth density after 15 hr. at 30oC, resistance to different levels of salinity, different pH levels, and different temperature degrees. Also, the isolates revealed their capabilities to solubilize phosphorus and potassium and to produce different phytohormones. The isolate X.M9 exhibited the highest growth performance in the form of 1.376,1.326,1.292,1.053 and 1.059 OD in most salts’ concentrations compared to all tested isolates respectively. In addition, it (X.M9) exhibited the highest resistance to low temperatures 10 and 15oC being 0.917 and 1.354 OD respectively. The isolate X.M9 recorded the highest IAA of 83.73 mg/100ml compared to all the tested isolates. The isolate X.M9 was identified using 16 SRNA sequencing and submitted to the GenBank database un-der accession number No: OP050187 as Stenotrophomonas rhizophila.
Show more [+] Less [-]Isolation and Identification of Nonstarter Lactic Acid Bacteria from Traditional Baramily Cheese
2021
Ahmed Ali | Youssef El-Kenany | Ihab Aumara | Osman Aita
Nonstarter lactic acid bacteria (NSLAB) have an important role in quality and safety of traditional Baramily cheese (Domiati cheese related type). Therefore, the objective of this study was to isolate and identify NSLAB with potential technological features from traditional Baramily cheese. Thirty-three samples of Baramily cheese randomly collected from retails in Cairo metropolitan area. The samples were characterized by physiochemical, textural profile and microbiological analysis. Ninety presumptive NSLAB (30 Lactobacillus spp < /em>. and 35 Enterococcus spp < /em>.) strains were isolated on MRS and Kenner-Faecal (KF) Streptococci media; and were characterized for growth temperature, salt tolerance and milk coagulation. All presumptive NSLAB isolates were tolerant to 6.5 % NaCl. Of them, 40 isolates were tolerant to 10.0 % NaCl including 16 presumptive Lactobacillus spp < /em>., and 24 presumptive Enterococcus spp < /em>. isolates based on the results, 11 representative isolates with potential technological features were selected for genetic identification using 16S rRNA technique, then were confirmed for growth and acidity development in skim milk within 48 h, and were tested for antimicrobial activity against some food spoilage and pathogenic microorganisms. The eleven isolates were identified as Ent. durans (1), Ent. faecalis (5), Lb. paraplantarum (1), Lb. plantarum (3), and Lb. rhamnosus (1). All isolated strains were confirmed active in skim milk, and some exhibited antimicrobial activity against tested food spoilage and pathogenic microorganisms. Both Lb. rhamnosus and Lb. plantarum were confirmed as the isolates with high activity in milk. Ent. durans and Ent. faecalis exhibited antimicrobial activity against Enterobacer aerogenes and E. coli. However, Lb. plantarum exhibited antimicrobial activity against both Enterobacer aerogenes, E. coli and Ps. aeruginosa. Listeria. monocytogenes, S. typhimurium, and Campylobacter. jejuni showed significant resistance to all tested NSLAB isolates. They can be concluded that the identified NSLAB isolated can be used to standardized and improve the quality and safety of Baramily cheese and other types related to Domiati cheese
Show more [+] Less [-]MORPHOLOGICAL AND MOLECULAR CHARACTERIZATION OF ECTOMYCORRHIZAL FUNGI ISOLATED FROM EGYPTIAN ENVIRONMENT
2007
Mona Zayed | Sh Selim | Wedad Eweeda | M Ali | A Hazem
In a trial to isolate and identify ectomycorrhi-zal fungi for the first time in Egypt 13 sporocarpes associated with rang of plants grown on Egyptian soils were collected, to be used for this purpose. Fungal isolates were obtained from collected spo-rocarpes and tested for ectomycorrhiza formation with Bauhinia sp. and Pinus seedlings. The paper sandwich technique was used for simultaneous inoculation of root apices Bauhinia to produce synchronously developing ectomycorrhizas. Typi-cal ectomycorrhizal roots were obtained within 14 days after inoculation with the collected strains. The isolates tested for ectomycorrhiza formation with Pinus sp. to ensure their identity by for-mation of distinct root characteristics on this host. Root colonization levels varied markedly among the tested fungal strains with respect to growth enhancement and NPK uptake of Pinus shoots and roots.
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