MOSP - Macao Scientific Publishers

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Genetic diversity of Fusarium oxysporum f. sp. cubense isolates from Malaysia

S. K. Leong, Z. Latiffah* and S. Baharuddin

Abstract: Genetic diversity of Fusarium oxysporum f. sp. cubense (FOC) isolates were analyzed using enterobacterial repetitive intergenic consensus PCR (ERIC-PCR), random amplified microsatellites (RAMS) and restriction fragment length polymorphism of Intergenic Spacer (RFLP-IGS) . The three molecular techniques showed intraspecific variations and the banding patterns generated using each technique were highly variable. UPGMA cluster analysis of the combined data of the three techniques showed 35.7 - 100% genetic similarity among the FOC isolates. Based on the dendrogram, most of the isolates including four isolates from Indonesia were clustered together in two main clusters. Sequence analysis of TEF-1 gene of some of the isolates of FOC using parsimony and distance methods also showed intraspecific variations. The highly variable banding patterns shown by using molecular methods supported the hypothesis that the isolates of FOC co-evolved with the edible bananas and dissemination of the pathogen was probably through infected rhizomes.[...] Read More.

Keywords: Fusarium oxysporum f.sp. cubense, enterobacterial repetitive intergenic consensus PCR, random amplified microsatellites, restriction fragment length polymorphism of Intergenic Spacer.

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In vitro activity of Thaumatococcus daniellii and Megaphrynium macrostachyum against spoilage fungi of white bread and â€˜Ebaâ€™, an indigenous staple food in Southern Nigeria

Grillo Joseph Adebayo* and Lawal Adekunle Kolawole

Abstract: Fresh white bread and ‘eba’ (a carbohydrate; > 80% starch, indigenous staple food in southern Nigeria) were purchased from traders in Lagos, Nigeria and stored under aseptic conditions in the laboratory at room temperature (27 ± 2°C) (11 h of darkness and 15 h of daylight) for duration of 144 h, during which samples were analyzed at 48 h intervals for fungal population using the plate count technique. The sensitivity of the spoilage fungi to aqueous and methanol extracts of leaves of Thaumatococcus danielli and Megaphrynium macrostachyum was determined using the broth dilution method. Fungal populations increased with hour of storage. For bread, Penicillium sp was dominant throughout with average populations of 2.0 x 101 and 8.01 x 106 cfu/g at 0 and 144 h, respectively, while Mucor sp was dominant in eba with average populations of 1.0 x 101 and 9.5 x 106 cfu/g at 0 and 96 h, respectively. For T. danielli, while the methanol extract had greater activity against the spoilage fungi than the aqueous extract, the reverse was observed for M. macrostachyum. The lowest minimum inhibitory concentration (MIC) of T. danielli was 25 mg/ml of the methanol extract against Saccharomyces cerevisiae and Saccharomyces chevalieri and its lowest minimum cidal concentration (MCC) was 50 mg/ml of the methanol extract against S. cerevisiae and Penicillium sp. For M. macrostachyum, the lowest MIC and MCC were 25 and 50 mg/ml of the aqueous extract respectively against S. chevalieri. The results highlight the potential of extracts of T. daniellii and M. macrostachyum as sources of alternative natural preservatives of bread and ‘eba’. [...] Read More.

Keywords: Thaumatococcus danielli, Megaphrynium macrostachyum, minimum inhibitory concentration, minimum cidal concentration.

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Comparison of cell growth and ethanol productivity on different pretreatment of rice straw hemicellulose hydrolysate by using Candida shehatae CICC 1766

Wan-Li Sun, and Wei-Yi Tao*

Abstract: In this work, the cell growth and ethanol productivity was tested for lignocellulosic biomass sugars of overliming-detoxified and NaOH-neutralized rice straw acid hydrolysate by using Candida shehatae CICC 1766. When the acetic acid reached 3 g/L in defined xylose medium, the final ethanol concentration was 33% of that in the medium without acetic acid addition. C. shehatae CICC 1766 could bear lower pH (ethanol yield 13.5 g/L at pH 4.0) in overliming-detoxified hydrolysate. At the optimal pH 5.0 the ethanol yield attended to 16.1 g/L. Ethanol yield in NaOH-neutralized hydrolysate was 13.7 g/L which is better than in overliming-detoxified hydrolysate (7.0 g/L) . It suggested that NaOH-neutralized hydrolysate could be directly fermented by using C shehatae CICC 1766.[...] Read More.

Keywords: Rice straw, Candida shehatae, hemicellulose hydrolysate, ethanol fermentation.

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Effect of Mentha longifolia L. ssp longifolia essential oil on the morphology of four pathogenic bacteria visualized by atomic force microscopy

Hajlaoui Hafedh*, Ben Abdallah Fethi, Snoussi Mejdi, Noumi Emira and Bakhrouf Amina

Abstract: The chemical composition and the antibacterial activity of the essential oil of Mentha longifolia L. ssp longifolia are being investigated in the present work. The minimal inhibitory concentration (MIC) of this oil against four gram+ and gram- reference bacteria including Salmonella typhimurium LT2, Escherichia coli ATCC 35218, Microccus luteus NCIMB 8166 and Staphylococcus aureus ATCC 25923 was used to study the morphological alteration of bacterial wall cell visualized by atomic force microscopy (AFM). The chemical analysis of the essential oil showed the presence of 34 compounds. The most important ones were: menthol (32.51%), menthone (20.71%), pulegone (17.76%), 1,8-cineole (5.61%), terpineol-4 (4.87%) and piperitone (2.16%). The MIC for bacteria ranged from 0.19 to 1.56 mg/ml. We found that M. longifolia (Menthol chemotype) has a high antibacterial effect. Cell wall of the tested bacteria was damaged at MIC concentrations. This susceptibility is more accentuated in S. typhimurium and E. coli (rod bacteria), whereas the damage is less important in coccoid bacteria (S. aureus and M. luteus).[...] Read More.

Keywords: Mentha longifolia, essential oil, Staphylococcus aureus, Microccus luteus, Escherichia coli, Salmonella typhimurium, cell morphology, atomic force microscope.

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Production and characterization of protease enzyme from Bacillus laterosporus

B. Usharani and M. Muthuraj*

Abstract: Production and partial purification of protease enzyme by Bacillus laterosporus was the aim of this study. B. laterosporus was allowed to grow in shake flask broth culture for purpose of inducing protease enzyme. The protease enzyme was purified by ammonium sulfate precipitation followed by dialysis and further concentrated by Amicon tubes. After concentration, the protein was subjected to 12% Zymogram gel with gelatin and the molecular weight of the protease enzyme was 15 kDa. The protease activity increased as there was increase in enzyme concentration; optimum substrate concentration (starch) was 1.0% (w/v); an optimum incubation temperature was 40°C. Purified protease enzyme had a maximum activity at pH 7.0 of phosphate buffer and the optimum incubation time was 24 h. The protease isolated from B. latrosporus is a mesophilic protease. It is stable at pH 7, at 40°C temperature, and this enzyme can be exploited commercially.[...] Read More.

Keywords: Bacillus laterosporus, PMSF, -mercaptoethanol, protease, fermentation.

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Beneficial effects of Bacillus subtilis on field-grown tomato in Burundi: Reduction of local Fusarium disease and growth promotion

Venant Nihorimbere, Marc Ongena*, Hélène Cawoy, Yves Brostaux, Pascal Kakana, Emmanuel Jourdan and Philippe Thonart

Abstract: The biocontrol potential of Bacillus subtilis S499 was evaluated on tomato in open field sites in low altitude area of the plain of Imbo in Burundi. This strain was tested in order to reduce the impact of an important fungal disease giving rise to large losses in local plantings. The causing pathogen was isolated from diseased leaves at different locations in the fields and identified as Fusarium most probably related to the semitectum species according to the fermentation profile, morphology and gene homology. Results of assays performed in two successive years on the same site indicated that bacterial treatment on seeds significantly increased growth and fruit yield of tomato plants and also provided a high level of protection against the disease caused by this Fusarium pathogen. This is the first reported study on this disease and based on the data collected, B. subtilis S499 may represent an effective solution as biocontrol agent where other chemical options have failed.[...] Read More.

Keywords: Bacillus subtilis, biocontrol, Fusarium disease, tomato plants.

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Isolating fungal endophyte from Paris polyphylla Smith var. yunnanensis and identifying their antibacterial ability

Q. Xuan, F. K. Bao, H. M. Pan and A. H. Liu*

Abstract: Eighteen fungal endophytes strains parasitizing the famous Chinese medicinal plant Paris polyphylla Smith var. yunnanensis (Franch.) Hand. Mazz were isolated from surface-sterilized plant tissues, such as rhizome, root, stem, leaf and flower. The effect of endophytes on the growth of human pathogenic microbes was evaluated in vitro, using disc diffusion assay. According to the characteristics of cultures and DNA sequences, the WRF7 and WRF7’ belonged to the species Penicillium chrysogenum. The extract of WRF7’ inhibited a broad range of human -pathogenic bacteria, but that of WRF7 almost had no similar effect. And the metabolites of WRF7’ could not stop the growth of test fungus Candida albicans. The study indicates that P. chrysogenum becomes fungal endophyte of Paris polyphylla Smith var. yunnanensis and its isolate WRF7’ makes metabolites that are inhibitory to all test bacteria in vitro. Therefore, the host plant suppressing pathogens owing to its endophytes and inhibitory mechanisms of endophytes to test bacteria and fungi are different.[...] Read More.

Keywords: Fungal endophyte, Paris polyphylla Smith var. yunnanensis (Franch.) Hand. Mazz, isolating, identifying, antibacterial ability.

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Seroprevalence of toxoplasmosis in high school girls in Bushehr city, South-west of Iran, 2009

Moradali Fouladvand*, Afshin Barazesh, Behrouz Naeimi, Keivan Zandi and Saeed Tajbakhsh

Abstract: Toxoplasmosis is a parasitic disease prevalent all over the world and it’s causal agent is Toxoplasma gondii. Toxoplasmosis is very important in pregnant women. Seroepidemiological survey of toxoplasmosis in young girls before marriage for identifying non immune girls could be used to prevent congenital toxoplasmosis. A seroepidemiological study of toxoplasma IgG-antibody in 516 high school girls was conducted. Sample cases were chosen randomly from public high school girls. Blood samples were collected and the obtained sera were examined for anti toxoplasma IgG and IgM antibodies by using ELISA method. Prevalence of toxoplasmosis in high school girls in Bushehr city was 22.1%. There was significant correlation between seropositivity of toxoplasma antibodies and factors such as, contact with cat, raw milk consumption, raw vegetables consumption and food consumption habits, but there was no significant correlation between seropositivity and availability of drinking water, keeping pet and information about toxoplasmosis. About 78% of high school girls in Bushehr city were seronegative in toxoplasma IgG antibody. It is recommended to the health managers to design the educational measures and develop the serological tests for identifying the non immune girls before marriage to prevent congenital toxoplasmosis.[...] Read More.

Keywords: Elisa, toxoplasmosis, high school girls, seroprevalence.

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Evaluation of serum copper level during Giardia intestinalis infection

Eser Kilic, Recep Saraymen, Ozlem Miman and Suleyman Yazar*

Abstract: Alterations of serum copper concentrations are commonly found in patients suffering from gastrointestinal infections and with hepatic, renal, cardiovascular and malignant diseases. In this study, we aimed to investigate the changes of total content of the essential element of copper level in patients infected with Giardia intestinalis. Copper concentration was measured in 64 patients who were positive for intestinal parasite of G. intestinalis. Scores obtained for the positive samples, their age and sex, matched 60 G. intestinalis negative healthy controls. The mean concentration of copper in serum was significantly higher in G. intestinalis positive subjects than in their controls both in females (p < 0.05) and males (p < 0.05). No correlation could be demonstrated between age and mean value of copper in G. intestinalis positive in both females and males control (p > 0.05). Copper level was found to be clearly increased in the patients infected with G. intestinalis compared to controls. Although, our findings suggest altered element metabolism due to the pathophysiologic changes of G. intestinalis, a detailed biochemical and molecular studies on large sample size are needed to put forward a relationship between G. intestinalis (may be other parasitic diseases) and serum element level changes.[...] Read More.

Keywords: Giardia Intestinalis, copper, atomic absorption.

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Prevalence of bacterial infection responsible for bovine mastitis

DaRong Cheng*, ShanYuan Zhu, ZhaoHua Yin, WenWei Ding, ZhiXia Mu, ZhiRui Su and HuaiChang Sun

Abstract: Mastitis continues to be the most economically important disease of dairy cattle, and current data on mastitis is even less readily available. To investigate into the prevalence of the pathogens responsible for bovine mastitis, 100 raw milk samples were obtained from the dairy cows with clinical or sub-clinical bovine mastitis in 5 farms in Jiangsu Province, China. All the samples were submitted to bacterial isolation and identification by morphologic examination and biotyping. The data revealed that Escherichia coli was the commonest organism in mastitis cases, being implicated in 82% cases, and Streptococcus uberis (53%) continues to be a prevalent pathogen closely followed by Staphylococcus aureus (41%), Streptococcus dysgalactiae (29%) and Streptococcus agalactiae (27%). In addition, Str. uberis and S. aureus were more frequently associated with clinical mastitis than sub-clinical case, while the infection rates of other bacteria were similar. Further more, Staphylococcus epidermids (15%) and Staphylococcus saprophyticus (10%), previously considered as naught pathogenic bacteria, were also detected in the diseased mammary gland of the problem cows.[...] Read More.

Keywords: Mastitis, bovine, bacteria, infection, prevalence.

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