1,852 research outputs found

    Halotolerant streptomycetes isolated from soil at Taif region, Kingdom of Saudi Arabia (KSA) I: Purification, salt tolerance range, biological and molecular identification

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    This study focuses on isolation and purification of some halotolerant streptomycetes from soil and sea water of western region, KSA as a source of salt tolerance gene(s). A few numbers (32) of streptomycetes-like colonies (SLC) were isolated and purified from two regions. From Jeddah, a number of 22 out of the 32 SLC were obtained, distributed between the sea water 12 (54.55%) and sea sediment soil 6 (27.27%).From Taif-soil, only 10 SLC were isolated. Results show that 31 SLC were grown on 3.5% salt, while, in the presence of 7.0% salt, 2, 3, 18, and 4 showed abundant (+++), moderate (++), weak (+), and in doubt (±) growth, respectively. Only five SLC were not able to grow at 7% salt. At the level of 10.5% salt, the number of SLC was decreased up to 4 (2 (+++), 1 (++) and 1(+)). In either 14% or 21% salt, four isolates were varied in their ability in growth as moderate or weak growth was recorded. These isolates were considered as halotolerant as they were able to grow in either the presence or normal growth medium. The four isolates which tolerate 14% salt (isolates 4 and 6) and 21% salt (isolates 2 and 8) were completely identified. The streptomycete isolate 2 appeared to be related to Streptomyces cirratus. Comparing the cultural, morphological and physiological characteristics of Streptomyces isolate 4 and 6, they were very likely to be strains of S. rishiriensis and S. alboflavus, respectively. Streptomyces isolate 8 was identified as a strain of S. luteogriseus. The nucleotide sequences of 16S rRNA gene was partially determined using the DNA template of the Streptomyces isolate 8. Results show that a final sequence of about 1462 nts was obtained and compared with eight universal Streptomyces and bacterial strains. This isolate could be classified as a new species of gray Streptomyces, and it was suggested to be named a new halotolerant Streptomyces sp. TSA-KSA strain (GenBank AB731746).Keywords: Streptomyces, halotolerant, identification, 16S rRNA, Taif, Kingdom of Saudi Arabia (KSA)African Journal of Biotechnology Vol. 12(19), pp. 2565-257

    Halotolerant streptomycetes isolated from soil at Taif region, Kingdom of Saudi Arabia II: RAPD-PCR analysis and salt tolerance-gene isolation

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    The genus Streptomyces is represented in nature by the largest number of species and varieties among the family Streptomycetaceae. This study aimed at extracting the DNA of four halotolerant Streptomyces strains followed by determination of DNA fingerprinting of them using a molecular tool. A trail to isolate salt tolerance gene(s) from their DNA was also aimed. RAPD-PCR technique was applied using seven RAPD-PCR primers. Results show that a total 71 fragments (65 polymorphic and six monomorphic) were amplified from the DNA of the four identified Streptomyces strains. The fragments were divided into polymorphic and monomorphic fragments. Three primers named OPA11, OPB15 and OPC07 did not show any monomorphic fragments. A number of 43 (7, 7, 8, 2, 9, 6 and 4) representing 60.56% were considered as unique DNA markers, and were amplified using OPA11, OPB15, OPC07, OPC18, OPD04, OPE05 and OPO14, respectively. Data shows similarity matrix between the four identified Streptomycs strains based on RAPD-PCR analysis ranged from 21.8 to 40.0. Results show that the P5CR gene was detected in the DNA extracts of three species, namely, Streptomyces cirratus-02; Streptomyces rishiriensis-04; Streptomyces luteogriseus-08, while, mtlD gene was only found in the DNA extracts of S. cirratus-02.Keywords: Streptomyces, halotolerant, salt tolerance genes, RAPD-PCR, Taif, KSAAfrican Journal of Biotechnology Vol. 12(13), pp. 1452-145

    Molecular studies on some soil-Streptomyces strains of western region, Kingdom of Saudi Arabia (KSA)

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    Random amplified polymorphic of DNA-polymerase chain reaction (RAPD-PCR) analysis of the DNA extracted from seven Streptomyces strains of western region, KSA was the aim of this study. Partial sequence of 16S rRNA gene of Streptomyces polychromogenes was also attempted. Results show that a total number of 240 amplified fragments were amplified using 10 RAPD-PCR primers (OPA11, OPB10, OPB15, OPC03, OPC07, OPC18, OPD05, OPE05, OPO14 and OPO17). A total number of 97, 73, 88, 79, 100, 108 and 82 fragments were amplified from the DNA extracts of S. polychromogenes, Streptomyces chattanoogensis, Streptomyces lucensis, Streptomyces antibioticus, Streptomyces violans, Streptomyces griseorubiginosus and Streptomyces violaceus, respectively. An obvious variation in the amplified fragments was recorded using the 10 RAPD-PCR primers (31, 27, 17, 19, 23, 29, 24, 26, 23 and 21 fragments for the primers, respectively). The highest similarity (66.7%) was found between S. lucensis and S. chattanoogensis; lowest similarity (35%) was recorded between the gray S. chattanoogensis and the red S. violaceus. The 16S rRNA gene was isolated via PCR from the DNA of S. polychromogenes (1) and sequenced. Fragments of 1003 and 837 nts were amplified using the forward and reverse primers, respectively. On matching, a final sequence of about 1452 nts (GenBank: JQ962978.1) was obtained and compared with five universal Streptomyces strains and four bacterial clones. The percent identities between the isolate of this study and the compared bacterial strains was lowest (79.1%) compared to HQ844464.1 and highest (98.3%) compared to EU520331.1. Based on the phenotypic and genotypic (16S rRNA gene) features, the strain could be classified as a new strain of S. polychromogenes.Keywords: Identification, Streptomyces, RAPD-PCR, 16S rRNA gene, KSAAfrican Journal of Biotechnology Vol. 12(19), pp. 2558-256

    Streptomyces noboritoensis isolated from rhizosphere soil and its use in controlling banana-tissue culture contaminants

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    In this study, the role of Streptomyces noboritoensis (14) isolated from the rhizosphere of banana plant and having antagonistic activity against the bacterial- and fungal-tissue culture contaminants was determined in vitro. Results show that the filtrate was more effective against the fungal-tissue culture contaminants than the bacterial-tissue culture contaminants. This was indicated when jars were fungifree and bacteria-free after one month and 21 days from incubation, respectively. Results of in vitro application show that the filtrate of S. noboritoensis (14) as a bio-control agent could be used for controlling the contaminants in banana. Data showed that treatment F (sterilized shoots treated with Streptomyces filtrate and cultivated on Streptomyces-inoculated medium) was the most effective followed by treatment E (sterilized shoots untreated with Streptomyces filtrate and cultivated on Streptomyces-inoculated medium). Therefore, the study suggests conducting further studies towards the use of streptomycetes in the biological control in a large scale production.Keywords: Streptomyces, tissue culture contaminants, antagonistic activities, bio-controlAfrican Journal of Biotechnology Vol. 12(20), pp. 2908-291

    Anatomy, morphology and evolution of the patella in squamate lizards and tuatara (Sphenodon punctatus)

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    The patella (kneecap) is the largest and best-known of the sesamoid bones, postulated to confer biomechanical advantages including increasing joint leverage and reinforcing the tendon against compression. It has evolved several times independently in amniotes, but despite apparently widespread occurrence in lizards, the patella remains poorly characterised in this group and is, as yet, completely undescribed in their nearest extant relative Sphenodon (Rhynchocephalia). Through radiography, osteological and fossil studies we examined patellar presence in diverse lizard and lepidosauromorph taxa, and using computed tomography, dissection and histology we investigated in greater depth the anatomy and morphology of the patella in 16 lizard species and 19 Sphenodon specimens. We have found the first unambiguous evidence of a mineralised patella in Sphenodon, which appears similar to the patella of lizards and shares several gross and microscopic anatomical features. Although there may be a common mature morphology, the squamate patella exhibits a great deal of variability in development (whether from a cartilage anlage or not, and in the number of mineralised centres) and composition (bone, mineralised cartilage or fibrotendinous tissue). Unlike in mammals and birds, the patella in certain lizards and Sphenodon appears to be a polymorphic trait. We have also explored the evolution of the patella through ancestral state reconstruction, finding that the patella is ancestral for lizards and possibly Lepidosauria as a whole. Clear evidence of the patella in rhynchocephalian or stem lepidosaurian fossil taxa would clarify the evolutionary origin(s) of the patella, but due to the small size of this bone and the opportunity for degradation or loss we could not definitively conclude presence or absence in the fossils examined. The pattern of evolution in lepidosaurs is unclear but our data suggest that the emergence of this sesamoid may be related to the evolution of secondary ossification centres and/or changes in knee joint conformation, where enhancement of extensor muscle leverage would be more beneficial.Sophie Regnault, Marc E. H. Jones, Andrew A. Pitsillides, John R. Hutchinso

    Taxonomy of Streptomyces strains isolated from rhizospheres of various plant species grown in Taif region, KSA, having antagonistic activities against some microbial tissue culture contaminants

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    This work was designed to identify and taxonomically classify Streptomyces strains isolated from the rhizospheres of various plant species; banana, rose, pomegranate and grape plants, having antagonistic activity against some microbial (bacteria and fungi) tissue culture contaminants. Streptomyces strains with the most potent antagonistic traits were identified using sequencing of 16S rRNA gene amplicons generated by PCR of DNA and blasting the sequences into GenBank. The Streptomyces isolates had antagonism against five identified fungi (Aspergillus fumigates, Aspergillus flavus, Aspergillus nidulans (1), Aspergillus nidulans (2), Cladosporium herbarum) and against five out of the 11 Gram positive bacilli bacterial contaminants. The three selected Streptomyces isolates (14, 15 and 17) were identified as strains of Streptomyces noboritoensis, Streptomyces albolongus and Streptomyces griseorubiginosus, respectively. Isolate 14 for which 1443 nucleotides were obtained was compared with eight universal Streptomyces strains and was classified as a new species of gray Streptomyces, to be named Streptomyces noboritoensis SSMA2-KSA strain. This study recommends conducting further studies on the use of streptomycetes in the biological control in a large scale production.Keywords: Taxonomy, Streptomyces, microbial tissue culture contaminants, antagonistic activities, 16S rRNAAfrican Journal of Biotechnology Vol. 12(14), pp. 1657-166

    The changes in various hydroxyproline fractions in aortic tissue of rabbits are closely related to the progression of atherosclerosis

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    <p>Abstract</p> <p>Background</p> <p>The most important function of collagen and elastin is to induce several mechanical parameters which are known to play a dominant role in governing mechanical properties of the blood vessels. The aortic tissue of rabbit is one of the important sources of collagen and elastin. The effects of high fat diet (HFD) on the hydroxyproline (Hyp) fractions in serum and aortic tissues of rabbits and collagen content in the aortic tissues of rabbits have not been documented before. The present study was undertaken to investigate the changes in Hyp fractions in serum and aortic tissues of rabbits and collagen content in the aortic tissues of rabbits during the progression of atherosclerosis. The atherosclerotic model used in this study was the New Zealand white rabbit (male; 12 weeks old). Twenty five rabbits were individually caged, and divided into control group (NOR; n = 10) and HFD group (CHO; n = 15). The control group was fed (100 g/day) of normal (NOR) diet for a period of 15 weeks. The HFD group was fed normal diet supplemented with 1.0% cholesterol plus 1.0% olive oil (100 g/day) for the same period of time.</p> <p>Results</p> <p>We found that the TC, LDLC, and TG (mg/dl) were significantly (p < 0.001) increased in HFD rabbits compared with control rabbits with percentage normalized changes of 1198%, 1591%, and 710%, respectively. The peptide-bound Hyp in the serum was significantly (P < 0.05) increased in HFD rabbits compared with control rabbits with percentage normalized change of 517% while it significantly (P < 0.01) decreased in aortic tissues of HFD rabbits compared with control rabbits with percentage normalized change of 65%. The protein-bound Hyp in the serum was significantly (P < 0.01) increased in HFD rabbits compared with control rabbits with percentage normalized change of 100%; the protein-bound Hyp in the aortic tissues of control rabbits was 235.30 ± 55.14 (Mean ± SD) while it was not detectable (ND) in HFD rabbits. Total serum Hyp showed no significant (P < 0.05) change in HFD rabbits compared with control rabbits while it was significantly (P < 0.05) decreased in aortic tissues of HFD rabbits compared with control rabbits with percentage normalized change of 73%. The total collagen was significantly (p < 0.01) decreased in aortic tissues of HFD rabbits compared with control rabbits with percentage normalized change of 73% which was supported by histological study.</p> <p>Conclusions</p> <p>These results suggest that percentage decrease in various Hyp fractions in aortic tissue of HFD rabbits are closely related to percentage decrease of collagen content in aortic tissues of HFD rabbits. These results also suggest that it may be possible to use the changes in various Hyp fractions in aortic tissues of rabbits as an important risk factor during the progression of atherosclerosis.</p

    Proceedings of the Salford Postgraduate Annual Research Conference (SPARC) 2011

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    These proceedings bring together a selection of papers from the 2011 Salford Postgraduate Annual Research Conference(SPARC). It includes papers from PhD students in the arts and social sciences, business, computing, science and engineering, education, environment, built environment and health sciences. Contributions from Salford researchers are published here alongside papers from students at the Universities of Anglia Ruskin, Birmingham City, Chester,De Montfort, Exeter, Leeds, Liverpool, Liverpool John Moores and Manchester

    False Data Injection Attacks Against Synchronization Systems in Microgrids

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    Synchronization systems play a vital role in the day-to-day operation of power systems and their restoration after cascading failures. Hence, their resilience to cyberattacks is imperative. In this paper, we demonstrate that a well-planned false data injection attack against the synchronization system of a generator is capable of causing tripping subsequently leading to instability and blackout. We present an analytical framework behind the design and implementation of the proposed cyberattack. Moreover, we derive and discuss the conditions for which a cyberattack interfering with a synchronizing signal can be successful. Effective physical mitigation strategies are then proposed to improve the cyber-resilience of synchronization systems. The proposed cyberattack model and mitigation strategies are verified for a microgrid test system using an OPAL-RT real-time simulator
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