MOSP - Macao Scientific Publishers

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The synthesis and role of hydroxyectoine in halophilic bacterium Halomonas ventosae DL7

Daochen Zhu,*, Chenxiang Wang, Shoko Hosoi-Tanabe, Weimin Zhang and Shinichi Nagata

Abstract: Hydroxyectoine and ectoine were accumulated in the moderately halophilic bacterium Halomonas ventosae DL7 as dominant compatible solutes in response to the external thermo- and osmo-stresses (30-42°C, 1-3 M NaCl). As the byproduct of ectoine, hydroxyectoine was directly converted from ectoine mediated by the ectoine hydroxylase in DL7, and the hydroxylase gene sequence was obtained by PCR. Further, the activity of ectoine hydroxylase of strain DL7 cells in vitro was determined at 30 to 42°C, and the thermo-stress conduce the inhibition of this enzyme activity. In addition, DL7 cells showed similar growth level when grown in presence of same level ectoine or hydroxyectoine (1 mM) in medium with high salinity (2-2.7 M NaCl). However, the presence of hydroxyectoine showed higher growth level than ectoine when DL7 cells were incubated at 42°C. The results showed that the alteration of temperature instead of salinity stress obviously stimulated the expression of ectoine hydroxylase, but inhibited its activity, and hydroxyectoine with ectoine together played an important role as thermo- and osmo-protectants in strain DL7 to cope with high temperature and salinity environment.[...] Read More.

Keywords: Halomonas ventosae DL7, compatible solutes, hydroxyectoine, ectoine hydroxylase, thermo-stress, osmo-stress.

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Survey of 3rd generation cephalosporin genes in multi-resistant Salmonella serotypes from septic poultry and an asymptomatic healthy pig from Nigeria

Akinlabi O. Ogunleye* and Steve A. Carlson

Abstract: Occurrence and spread of Salmonella genes encoding AmpC and extended-spectrum beta-lactamases (ESBL) is a major public health problem worldwide. These genes have been identified in Salmonella serotypes all over the world yet there is paucity of reports on these genes in Nigeria, despite the phenotypic evidence of resistance to beta- lactam drugs. The current work used a multiplex PCR to identify beta-lactam resistance genes in five Nigerian-origin Salmonella isolates exhibiting resistance to third-generation cephalosporins. The isolates included four strains isolated from septic poultry (two strains of Salmonella enterica serotype Kentucky and two strains of presumptive S. enterica serotype Pullorum) and one S. enterica serotype Give isolated from one of two hundred asymptomatic pigs. The predominant genes found in these Nigeria serotypes include: TEM, SHV, GES, OXA-2, ACCM, FOX, ECBM and DHAM. The presence of these plasmid-borne genes underscores the potential health risk of antibiotic resistance transfer from food animals to human in Nigeria because third-generation cephalosporin drugs are still the drug of choice in treating life-threatening systemic infections in Nigeria.[...] Read More.

Keywords: Salmonella, 3rd generation cephalosporin, multi-resistant, Nigeria.

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Isolation, identification and characterization of oleaginous fungi from the soil of Qinghai Plateau that utilize D-xylose

Shi Lin Li, Shun Li Feng, Zeng Ting Li, Hui Xu, Ying Peng Yu, Dai Rong Qiao and Yi Cao*

Abstract: We established a new screening method for oleaginous fungus, which was consistent with sudan black B stained but more convenient and faster. 11 strains of oleaginous fungi that utilize D- xylose were isolated from the soil of Qinghai Plateau by this method. These strains belong to 7 species by molecular identifying, they are Tilletiopsis albescens, Backusella ctenidia, lectosphaerella sp., Gibberella fujikuroi, Fusarium sp. Aspergillus fumigatus and Penicillium decumberns; 4 of which were the first time found to produce lipids, they are Tilletiopsis albescens, Backusella ctenidia, lectosphaerella sp. and Gibberella fujikuroi. In addition, these oleaginous fungi could accumulate certain microbial oil by fermenting D-xylose and carboxymethyl cellulose (CMC), whose composition is similar to vegetable oil and can be converted to biodiesel. These microorganism species that may use cheap lignocellulose to produce microbial oil, it can pave lane for biodiesel production with low cost.[...] Read More.

Keywords: Oleaginous fungi, D-xylose, carboxymethyl cellulose, biodiesel.

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Evaluation of anticarcinogenicity effect of Artemia urmiana by Salmonella typhimurium TA 100 strain

Masumeh Abbasi, Saman Mahdavi* and Sedigheh Mehrabian

Abstract: Free radicals are produced during oxidative metabolism in body and they can attack all components of cells and cause cellular changes and early aging. Antioxidant materials role for balance maintenance in cells has currently attracted more attention. The aim of this study is investing of antimutation effect of Artemia, cyst and decapsulated egg extract by Ames test and Salmonella typhimurium TA 100 strain. These extract prevent reverse mutation caused by carcinogenic materials. In comparison with positive controls (sodium azid, KMno4, cresol) and negative control (distilled water) antimutagenicity properties of Artemia was evaluated and confirmed. In addition, the value of astaxanthin in those extracts was assayed. For quality analysis and separation of astaxanthin, we used thin-layer chromatography (TLC) chromatography and column chromatography, respectively. Then, the presense of astaxanthin in these extracts was confirmed by spectrometer IR test. The results showed that antimutagenicity properties of Artemia urmiana are the same with other salty water Artemia. Antimutagenicity and anticarcinogenicity properties in decapsulated egg, dried Artemia and cyst are 85, 70 and 100%, respectively.[...] Read More.

Keywords: Ames test, anticarcinogenicity, antioxidant, Artemia urmiana, Salmonella typhimurium TA 100.

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Response surface methodology for optimizing process parameters for the mass production of BEAUVERIA BASSIANA conidiospores

Full Length Research Paper

Abstract: BEAUVERIA BASSIANA is an insect pathogenic fungus and is currently being exploited as an effective commercial mycoinsecticide. Solid state fermentation is the most efficient way to mass produce B. BASSIANA conidiospores on solid substrates. Statistical optimization strategy was adopted to maximize the conidia production through solid state fermentation. Four substrates viz., rice (polished), crushed sorghum, wheat bran and rice bran at variable moisture content and yeast extract concentration were used. A full factorial central composite design was used to design the experiment and response surface method was used to study the optimal parameters required for large scale production. Optimization of the two most important factors like moisture content and yeast extract concentration at varied levels conferred best conidial yield of 28.8 × 109 /gm for the mixed substrate rice + wheat bran at 35% moisture content and 1.5% yeast extract concentration.[...] Read More.

Keywords: Beauveria bassiana, central composite design, conidiospores, response surface methodology, solid state fermentation.

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Effect of glucose supplementation on CANDIDA ALBICANS virulence in immunosuppressed Swiss albino mice (MUS MUSCULUS)

Full Length Research Paper

Abstract: We investigated the effect of dietary carbohydrate supplementation on CANDIDA ALBICANS colonization using an animal model and a CANDIDA strain with both high phospholipase and proteinase activity. Normal and immunosuppressed mice were inoculated intraperitonially with C. ALBICANS and were allowed free access to drinking water supplemented or not with glucose. Blood and different organs including liver, spleen, lung and kidney were aseptically collected every 72 h post-infection. The presence and the growth of C. ALBICANS in blood and each organ were investigated. We also performed histopathologic investigations on each organ to assess tissue structure, the presence of C. ALBICANS, and its form (blastospore or hyphae). The results showed that on the third day post-inoculation, the cfu of C. ALBICANS per organ was significantly higher in mice inoculated by C. ALBICANS and receiving the glucose as supplement (433 cfu/liver) comparatively to the group receiving C. ALBICANS only (140 cfu/liver). Histological analysis revealed the presence of CANDIDA cells in blastospore and hyphal form, particularly in the CANDIDA-infected glucose-supplemented mice whose livers displayed oedema and leukocyte infiltration with a high density of polymorphonuclear cells. Overall results indicate that dietary glucose supplementation leads to higher rates of CANDIDA growth and invasion. This suggests that glucose restriction could be a possible way to control C. ALBICANS pathogenesis IN VIVO.[...] Read More.

Keywords: Candida albicans, glucose, immunosuppressed mice, experimental infection.

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The functional roles of the residue tyrosine at position 26 in staphylococcal enterotoxin C2

Hongbo Wang, Junyi Zhou, Mingkai Xu*, Huiwen Zhang and Chenggang Zhang

Abstract: Bacterial superantigen Staphylococcus aureus enterotoxin C2 (SEC2) is a very potent activator of T cells. Previous crystal studies on SEC2 showed that residue Tyr26 which is located near the T cell receptor (TCR) binding sites could potentially participate in T cell activating. In SEC1, a superantigen highly homologous to SEC2, the residue Val26 played a critical role in stimulating certain V expansion. Moreover, residues 20, 22 and 26 in SEC1 determined its serologic cross-reaction. In order to investigate the potential roles of Tyr26 in SEC2, two SEC2 mutants SEC2 (Y26V) and SEC2(Y26A) were constructed by site-directed mutagenesis. The activities and toxicities of the two mutants were determined both in vivo and in vitro. Results showed that both SEC2 (Y26V) and SEC2 (Y26A) remained potent immune stimulating activities compared with native SEC2. SEC2 (Y26V) had a decreased pyrogenic effect on rabbit model. Both of the two mutants had significantly decreased binding affinities to anti-SEC2 IgG. Our result indicated that Tyr26 is a critical site for the serological characters of SEC2 rather than for its superantigen activity. This may also provide an insight in constructing a novel mutant to substitute native SEC2 in cancer immunotherapy avoiding being neutralized by anti-SEC2 IgG in vivo.[...] Read More.

Keywords: Staphylococcal enterotoxin C2, Site-directed mutagenesis, superantigen, serological, property.

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Isolation of a bacteriophage against Salmonella Dublin and determination of its physical resistance under varied in vitro conditions

Mudit Chandra*, Sunita Thakur, Deepti Narang and H. M. Saxena

Abstract: In the present study a phage against Salmonella Dublin was isolated using agar overlay technique. On physical characterization of the phage (pH, temperature and sun light exposure) it was found that the phage could survive at varied pH conditions with reduction in its numbers. A temperature of above 50°C and direct sunlight beyond 5 days was found to be deleterious for survival of the phage.[...] Read More.

Keywords: Salmonella, bacteriophage, physical parameters, pH, sunlight.

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mRNA expression of iron metabolism relation genes in macrophages by infection with Salmonella typhimurium

Pan Xin

Abstract: A total number of 13 iron metabolism relation genes expression profiles of RAW264.7 murine macrophages infected or uninfected with Salmonella typhimurium were tested by real-time polymerase chain reaction (RT-PCR) to evaluate the metabolism of iron in host-pathogen interplay. The living wild-type S. typhimurium induces expression of the transferrin receptor (Tfr1) in host cell macrophages, which results in a sustained increase of the labile iron pool inside the host cell after 1 or 24 h infection. Gene expression analysis showed that wild-type S. typhimurium drives an active iron acquisition program with induction of ferrireductase (Steap3), iron membrane transporter Dmt1, and iron regulatory proteins (Irp1 and Irp2), while not too much iron efflux changing through ferriportin (Fpn1). The spiA-Salmonella mutant strain used in our studies also caused an increase in Tfr1 at 1 or 24 h, but leading to decrease in Fpn1 at 24 h as compared with 1 h. The assessment of the labile iron pool after infection with spiA- Salmonella after 24 h shows an increase. The same of these two phenotypes allowed iron overload in macrophage and became one of the reasons for Salmonella survival inside the macrophage.[...] Read More.

Keywords: Macrophage, Salmonella, iron metabolism.

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Survey of Ascaris lumbricoides among pupils of primary school in Jos south local government area of Plateau State, Nigeria

Dangana A.,* Abayomi R. O., Way G. D. and Akobi O. A.

Abstract: Ascaris lumbricoides was surveyed among pupils of primary schools in Jos south local government. Four schools were visited: National Research Institute Staff Primary School, Rita Primary School, Joseph Primary School and St Andrew Primary School. A total of 471 samples were collected from pupils of these schools and processed using formol-ether concentration technique. Only 1 (0.2%) pupil from St Andrew Primary School was positive for A. lumbricoides. The prevalence of the infection among the age group showed that 1 (0.9%) in the age group (5 to 9) years was positive while the sex distribution showed a prevalence of 1(0.4%) among the male and no positive case was recorded among the females. The overall prevalence of other parasitic infections was 8.3% with hookworm having the highest prevalence of (5.3%), followed by Entamoeba histolytica with (0.6%), and Giardia lamblia (0.5%), while Hymenolepis nana and Taenia species had both a prevalence of (0.2%). Key word: Ascaris lumbricoides, hookworm, Taenia, prevalence, primary schools, Jos, Plateau State, Nigeria.[...] Read More.

Keywords: Ascaris lumbricoides, hookworm, Taenia, prevalence, primary schools, Jos, Plateau State, Nigeria.

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