Commenced in January 2007
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Edition: International
Paper Count: 5

Search results for: rhodotorula spp. 74

5 Inactivation of Rhodotorula spp. 74 with Cold Atmospheric Plasma

Authors: Zoran Herceg, Višnja Stulić, Tomislava Vukušić, Anet Režek Jambrak

Abstract:

High voltage electrical discharge is a new technology used for inactivation of pathogen microorganisms. Pathogen yeasts can cause diseases in humans if they are ingested. Nowadays new technologies have become the focus of researching all over the world. Rhodotorula is known as yeast that can cause diseases in humans. The aim of this study was to examine whether the high voltage electrical discharge treatment generated in gas phase has an influence on yeast reduction and recovery of Rhodotorula spp 74 in pure culture. Rhodotorula spp. 74 was treated in 200 mL of model solution. Treatment time (5 and 10 min), frequency (60 and 90 Hz) and injected gas (air or argon 99,99%) were changed. Titanium high voltage needle was used as high voltage electrode (positive polarity) through which air or argon was injected at the gas flow of 0.6 L/min. Experimental design and statistical analyses were obtained by Statgraphics Centurion software (StatPoint Technologies, Inc., VA, USA). The best inactivation rate 1.7 log10 reduction was observed after the 10 min of treatment, frequency of 90 Hz and injected air. Also with a longer treatment time inactivation rate was higher. After the 24 h recovery of treated samples was observed. Therefore the further optimization of method is needed to understand the mechanism of yeasts inactivation and cells recovery after the treatment. Acknowledgements: The authors would like to acknowledge the support by Croatian Science Foundation and research project ‘Application of electrical discharge plasma for preservation of liquid foods’.

Keywords: rhodotorula spp. 74, electrical discharge plasma, inactivation, stress response

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4 Prevalence and Fungicidal Activity of Endophytic Micromycetes of Plants in Kazakhstan

Authors: Lyudmila V. Ignatova, Yelena V. Brazhnikova, Togzhan D. Mukasheva, Ramza Zh. Berzhanova, Anel A. Omirbekova

Abstract:

Endophytic microorganisms are presented in plants of different families growing in the foothills and piedmont plains of Trans-Ili Alatau. It was found that the maximum number of endophytic micromycetes is typical to the Fabaceae family. The number of microscopic fungi in the roots reached (145.9±5.9)×103 CFU/g of plant tissue; yeasts - (79.8±3.5)×102 CFU/g of plant tissue. Basically, endophytic microscopic fungi are typical for underground parts of plants. In contrast, yeasts more infected aboveground parts of plants. Small amount of micromycetes is typical to inflorescence and fruits. Antagonistic activity of selected micromycetes against Fusarium graminearum, Cladosporium sp., Phytophtora infestans and Botrytis cinerea phytopathogens was detected. Strains with a broad, narrow and limited range of action were identified. For further investigations Rh2 and T7 strains were selected, they are characterized by a broad spectrum of fungicidal activity and they formed the large inhibition zones against phytopathogens. Active antagonists are attributed to the Rhodotorula mucilaginosa and Beauveria bassiana species.

Keywords: endophytic micromycetes, fungicidal activity, prevalence, plants

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3 Antifungal Protein ~35kDa Produced by Bacillus cereus Inhibits the Growth of Some Molds and Yeasts

Authors: Saleh H. Salmen, Sulaiman Ali Alharbi, Hany M. Yehia, Mohammad A. Khiyami, Milton Wainwright, Naiyf S. Alharbi, Arunachalam Chinnathambi

Abstract:

An antifungal protein synthesized by Bacillus cereus has been partially purified by the use of ammonium sulfate precipitation and Sephadex-G-200 column chromatography. The protein was produced from Bacillus cereus grown in potato Dextrose Broth Medium (PDB) at 30 ºC for 3 days at 100 rpm. The protein showed antagonistic effect against some fungi and yeasts. Crude extract from medium and semi-purified protein were tested in vitro against both fungi and yeasts using the disc diffusion method in order to detect the inhibitory effect of the protein. Zones of inhibition of the following diameter were found (mm) were Alternaria alternate (28), Rhodotorula glutinis (20), Fusarium sp. (16), Rhizopus sp. (15), Penicillium digitatum (13), Mucor sp. (13) and Aspergillus niger (10). The isolated protein was found to have a molecular weight of ~35kDa by sodium deodecyl sulfate-poly acrylamide gel electrophoresis. The data showed that the protein of Bacillus cereus has antifungal activity, a fact which points to the possibility of using it as a bio-control agent against some fungi, findings which emphasize the potential role of B. cereus as an important bio-control agent.

Keywords: bacillus cereus, ~35kDa protein, molds, yeasts

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2 Prevalence and Comparison for Detection Methods of Candida Species in Vaginal Specimens from Pregnant and Non-Pregnant Saudi Women

Authors: Yazeed Al-Sheikh

Abstract:

Pregnancy represents a risk factor in the occurrence of vulvovaginal candidiasis. To investigate the prevalence rate of vaginal carriage of Candida species in Saudi pregnant and non-pregnant women, high vaginal swab (HVS) specimens (707) were examined by direct microscopy (10% KOH and Giemsa staining) and parallel cultured on Sabouraud Dextrose Agar (SDA) as well as on “CHROM agar Candida” medium. As expected, Candida-positive cultures were frequently observed in pregnant-test group (24%) than in non-pregnant group (17%). The frequency of culture positive was correlated to pregnancy (P=0.047), parity (P=0.001), use of contraceptive (P=0.146), or antibiotics (P=0.128), and diabetic-patients (P < 0.0001). Out of 707 HVS examined specimens, 157 specimens were yeast-positive culture (22%) on Sabouraud Dextrose Agar or “CHROM agar Candida”. In comparison, the sensitivities of the direct 10% KOH and the Giemsa stain microscopic examination methods were 84% (132/157) and 95% (149/157) respectively but both with 100% specificity. As for the identity of recovered 157 yeast isolates, based on API 20C biotype carbohydrate assimilation, germ tube and chlamydospore formation, C. albicansand C. glabrata constitute 80.3 and 12.7% respectively. Rates of C. tropicalis, C. kefyr, C. famata or C. utilis were 2.6, 1.3, and 0.6% respectively. Sachromyces cerevisiae and Rhodotorula mucilaginosa yeasts were also encountered at a frequency of 1.3 and 0.6% respectively. Finally, among all recovered 157 yeast-isolates, strains resistant to ketoconazole were not detected, whereas 5% of the C. albicans and as high as 55% of the non-albicans yeast isolates (majority C. glabrata) showed resistance to fluconazole. Our findings may prove helpful for continuous determination of the existing vaginal candidiasis causative species during pregnancy, its lab-diagnosis and/or control and possible measures to minimize the incidence of the disease-associated pre-term delivery.

Keywords: vaginal candidiasis, Candida spp., pregnancy, risk factors, API 20C-yeast biotypes, giemsa stain, antifungal agents

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1 Antimicrobial Activities of Lactic Acid Bacteria from Fermented Foods and Probiotic Products

Authors: Alec Chabwinja, Cannan Tawonezvi, Jerneja Vidmar, Constance Chingwaru, Walter Chingwaru

Abstract:

Objective: To evaluate the potential of commercial fermented / probiotic products available in Zimbabwe or internationally, and strains of Lactobacillus plantarum (L. plantarum) as prophylaxis and therapy against diarrhoeal and sexually transmitted infections. Methods: The antimicrobial potential of cultures of lactobacilli enriched from 4 Zimbabwean commercial food/beverage products, namely Dairibord Lacto sour milk (DLSM), Probrand sour milk (PSM), Kefalos Vuka cheese (KVC) and Chibuku opaque beer (COB); three probiotic products obtainable in Europe and internationally; and four strains of L. plantarum obtained from Balkan traditional cheeses and Zimbabwean foods against clinical strains of Escherichia coli (E. coli) and non-clinical strains of Candida albicans and Rhodotorula spp. was assayed using the well diffusion method. Three commercial Agar diffusion assay and a competitive exclusion assay were carried out on Mueller-Hinton agar. Results: Crude cultures of putative lactobacillus strains obtained from Zimbabwean dairy products (Probrand sour milk, Kefalos Vuka vuka cheese and Chibuku opaque beer) exhibited significantly greater antimicrobial activities against clinical strains of E. coli than strains of L. plantarum isolated from Balkan cheeses (CLP1, CLP2 or CLP3) or crude microbial cultures from commercial paediatric probiotic products (BG, PJ and PL) of a culture of Lactobacillus rhamnosus LGG (p < 0.05). Furthermore, the following has high antifungal activities against the two yeasts: supernatant-free microbial pellet (SFMP) from an extract of M. azedarach leaves (27mm ± 2.5) > cell-free culture supernatants (CFCS) from Maaz Dairy sour milk and Mnandi sour milk (approximately 26mm ± 1.8) > CFCS and SFMP from Amansi hodzeko (25mm ± 1.5) > CFCS from Parinari curatellifolia fruit (24mm ± 1.5), SFMP from P. curatellifolia fruit (24mm ± 1.4) and SFMP from mahewu (20mm ± 1.5). These cultures also showed high tolerance to acidic conditions (~pH4). Conclusions: The putative lactobacilli from four commercial Zimbabwean dairy products (Probrand sour milk, Kefalos Vuka vuka cheese and Chibuku opaque beer), and three strains of L. plantarum from Balkan cheeses (CLP1, CLP2 or CLP3) exhibited high antibacterial activities, while Maaz Dairy sour-, Mnandi sour- and Amansi hodzeko milk products had high antifungal activities. Our selection of Zimbabwean probiotic products has potential for further development into probiotic products for use in the control diarrhea caused by pathogenic strains of E. coli or yeast infections. Studies to characterise the probiotic potential of the live cultures in the products are underway.

Keywords: lactic acid bacteria, Staphylococcus aureus, Streptococcus spp, yeast, inhibition, acid tolerance

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