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CULTURAL, MORPHOLOGICAL, PHYSIOLOGICAL AND MOLECULAR STUDIES ON SOME STREPTOMYCETE ISOLATES
2005
H Abdel-Fattah
In this study, three isolates of Streptomyces isolated from Egyptian soil at Giza Governorate and belonging to red series were identified based on their cultural, morphological and physiological characters. According to the key proposed by Pridham and Tresner (1974), the experimental isolates ST55, ST71 and ST86 ap-peared to be related to S. lincolnensis, S. venezuelae and S. umbrinus, respectively. In addition, random amplified polymorphic DNA (RAPD)-polymerase chain reac-tion (PCR) was used to amplify the DNA genome of the three applied isolates and an identified strain to determine their fingerprints. This was carried out using 10-decamer oligonucleotides, i.e., OP-A02, OP-D01, OP-D02, OP-D05, OP-D06, OP-D07, OP-D08, OP-D11, OP-D18 and OP-D20. The PCR amplified products were detected by electrophoresing on 1.5% agarose gel and visualized by staining in eth-idium bromide and UV trasilluminator. Results showed that the same oligonucleo-tide flanking fragments differed from one isolate to another with different sizes. Monomorphic and polymorphic fragments were amplified confirming the molecular relationships as well as the genetic diversity between the four applied strains of Streptomyces. Based on the statistical analysis of RAPD-PCR polymorphisms a de-gree of similarities ranged from 33.9 to 59.2 % was found. Furthermore, frag-ment(s), whatever absent or present, were found to be unique molecular markers and could be used for characterization of some isolates. This result supported the idea for using the RAPD-PCR technique for classification of Streptomyces isolates.
Mostrar más [+] Menos [-]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
Mostrar más [+] Menos [-]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.
Mostrar más [+] Menos [-]dentification of some phaseolus genotypes by alcohol, glucose-6- [hosphate, glutamate and malate dehydrogenase isozymes
2000
Saker, M.M. | Hassan, A.E. (Suez Canal Univ., Ismaileyah (Egypt). Faculty of Agriculture)Abdel-Rahman, S.M.