The Journal of General and Applied Microbiology
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Volume 52 , Issue 2
Showing 1-10 articles out of 10 articles from the selected issue
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  • Hanan Ghozlan, Hisham Deif, Rania Abu Kandil, Soraya Sabry
    Volume 52 (2006) Issue 2 Pages 63-72
    Released: June 16, 2006
    JOURNALS FREE ACCESS
    Screening bacteria from different saline environments in Alexandria. Egypt, lead to the isolation of 76 Gram-negative and 14 Gram-positive moderately halophilic bacteria. The isolates were characterized taxonomically for a total of 155 features. These results were analyzed by numerical techniques using simple matching coefficient (SSM) and the clustering was achieved by the unweighed pair-group method of association (UPGMA). At 75% similarity level the Gram-negative bacteria were clustered in 7 phena in addition to one single isolate, whereas 4 phena represented the Gram-positive. Based on phenotypic characteristics, it is suggested that the Gram-negative bacteria belong to the genera Pseudoalteromonas, Flavobacterium, Chromohalobacter, Halomonas and Salegentibacter, in addition to the non-identified single isolate. The Gram-positive bacteria are proposed to belong to the genera Halobacillus, Salinicoccus, Staphylococcus and Tetragenococcus. This study provides the first publication on the biodiversity of moderately halophilic bacteria in saline environments in Alexandria, Egypt.
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  • Bundit Fungsin, Masako Takashima, Takashi Sugita, Suparp Artjariyasrip ...
    Volume 52 (2006) Issue 2 Pages 73-81
    Released: June 16, 2006
    JOURNALS FREE ACCESS
    Seven strains of ballistoconidiogenous yeasts that contain xylose, form Q-10 ubiquinone, propagate by budding and don't produce stalk conidia were isolated from plant leaves collected in Thailand and were found to represent two new species. The taxonomic properties of the two species coincided with the genus Bullera so they are described as Bullera koratensis sp. nov. and Bullera lagerstroemiae sp. nov. In phylogenetic trees based on the nucleotide sequences of 18S ribosomal DNA and the D1/D2 domain of 26S rDNA, these two species are located in the Trichosporonales clade (Cryptococcus humicola-Trichosporon lineage).
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  • Jun Cai, Liang Xiao, Bing Yan, Guan Bin, Yuehua Chen, Gaixin Ren
    Volume 52 (2006) Issue 2 Pages 83-89
    Released: June 16, 2006
    JOURNALS FREE ACCESS
    Culture supernatant of Bacillus thuringiensis 9816C had high toxicity against Helicoverpa armigera and Spodoptera exigua. However, it lost insecticidal activities after being bathed in boiling water for 5 min. Acrystalliferous mutants of Bt9816C (Bt9816C-NP1 and Bt9816C-NP2) cured of its endogenous plasmids no longer possessed vip3A gene and toxicity. The 89 kD protein which existed in Bt9816C supernatant disappeared in the two mutants' supernatant; nevertheless, the two mutants still exhibited hemolytic and phospholipase C activity as Bt9816C did. The vip3A gene of Bt9816C, vip3Aa18, was cloned and expressed in Escherichia coli BL21. Bioassay demonstrated that the recombinant E. coli had high toxicity against S. exigua. Taken together, it suggested that Vip3A protein was responsible for the toxicity of Bt9816C culture supernatants.
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  • Hideki Nagahama, Yutaka Sakamoto, Kouji Matsumoto, Hiroshi Hara
    Volume 52 (2006) Issue 2 Pages 91-98
    Released: June 16, 2006
    JOURNALS FREE ACCESS
    In the Escherichia coli pgsA null mutant, which lacks the major acidic phospholipids, the Rcs phosphorelay signal transduction system is activated, causing thermosensitive growth. The mutant grows poorly at 37°C and lyses at 42°C. We showed that the poor growth at 37°C was corrected by disruption of the rcsA gene, which codes for a coregulator protein that interacts with the RcsB response regulator of the phosphorelay system. However, mutant cells still lysed when incubated at 42°C even in the absence of RcsA. We conclude that the activated Rcs phosphorelay in the pgsA null mutant has both RcsA-dependent and -independent growth inhibitory effects. Since the Rcs system has been shown to positively regulate the essential cell division genes ftsA and ftsZ independently of RcsA, we measured cellular levels of the FtsZ protein, but found that the growth defect of the mutant at 42°C did not involve a change in the level of this protein.
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  • Sule Senses-Ergul, Zekiye Yesim Ozbas
    Volume 52 (2006) Issue 2 Pages 99-106
    Released: June 16, 2006
    JOURNALS FREE ACCESS
    In this study, 129 Turkish high-sugar products were examined in terms of their yeast flora and 73 representative strains were isolated. Yeast isolates were identified at species level by using Apilab Plus (bioMérieux, France), a specific computer program developed for ID 32C strips (bioMérieux, France). While one of the isolates could be identified at genus level as Aureobasidium, 66 of them were identified as 21 species belonging to 8 different genera. The distribution of these isolates were as follows: Candida (38), Rhodotorula (8), Zygosaccharomyces (7), Cryptococcus (6), Saccharomyces (3), Debaryomyces (2), Pichia (1) and Torulaspora (1). Approximately 70% of the isolates were found to have the ability to grow on media with 50% (w/w) glucose. Hence, they were characterized as xerotolerant strains. Although Zygosaccharomyces rouxii is known as the most xerotolerant yeast species, only two strains of Z. rouxii could be isolated from Turkish high-sugar foods. During identification studies, it was observed that ID 32C test strips should certainly be supported by morphological and physiological tests for obtaining more reliable identification results. If not, closely related yeast species such as anamorph and telemorph forms can not be distinguished.
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