MOSP - Macao Scientific Publishers

文章

The antifungal susceptibilities of oral Candida spp. isolates from HIV-infected patients

Dilek Satana*, Gonca Erkose Genc and Zayre Erturan

Abstract: Oropharyngeal candidiasis (OPC) is the most common HIV related oral lesion. Most patients are infected with a strain originally present as a commensal of the oral cavity. The resistance of Candida isolates to antifungal drugs is important due to morbidity and mortality. The aim of our study was to investigate the antifungal susceptibility profiles of oral Candida spp. which were isolated from HIV-infected patients. In vitro susceptibility tests were performed using the broth microdilution method recommended by the Clinical and Laboratory Standard Institute (CLSI). A total of 67 oral Candida isolates from colonized HIV-infected patients, which were previously isolated and identified were included in this study. MIC ranges were 0.12 - 4.0, 0.12 - 16, 0.03 - 1.0, 0.03 - 1.0, and 0.03 - 0.25 µg/ml for amphotericin B, fluconazole, itraconazole, ketoconazole and voriconazole, respectively. All isolates were fully susceptible to voriconazole. Sixty five (97%) of all isolates were determined fully susceptible to amphotericin B, 66 (98.5%) to fluconazole, 64 (95.5%) to ketoconazole and 50 (88%) to itraconazole. No resistance was detected to fluconazole and voriconazole in oral Candida strains isolated from colonized Turkish HIV positive patients. Antifungal resistance was detected in 8.96% (6 strains) of all isolates tested.[...] Read More.

Keywords: HIV, Candida, oropharyngeal carriage, antifungal agents, antifungal susceptibility.

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Investigation of cellular hydrophobicity and surface activity effects of biosynthesed biosurfactant from broth media of PTCC 1561

Golamreza Dehghan Noudeh,*, Ali Dehghan Noodeh, Mohammad Hassan Moshafi, Effat Behravan, Masoud Ahmadi Afzadi and Mahsa Sodagar

Abstract: Biosurfactants as surface active molecules that are synthesized by microorganisms. These substances include many advantages in comparison with chemical surfactants. For instance they have lower toxicity, higher biodegradability, better environmental compatibility, higher foaming activity, and specific activity at extreme temperatures, pH ranges, and the ability to be synthesized from renewable feed stocksin. In this study, the production of biosurfactant, produced by PTCC 1561 was studied. This bactrium was grown in a nutrient broth medium and the production of biosurfactant was evaluated by the surface tension and emulisification index (E24), each 24 h. The production of biosurfactant was studied in different conditions, including time of incubation, temperature, aeration rate and presence of several additives containing mineral salts and hydrocarbons. Finally, the optimum condition for production of the biosurfactant was determined and the biosurfactant identity was investigated using chemical and spectroscopy methods. The maximum biosurfactant production by Pseudomonas aeruginosa PTCC 1561, was exhibited when it was grown in Brain Hearth Broth medium containing Fecl3, ZnSO4, FeSO4, starch and olive oil incubated in a 200 rpm shaker incubator at 37°C for 24 h . The structure of produced biosurfactant sugar-lipid was confirmed by chemical and spectroscopy methods.[...] Read More.

Keywords: Biosurfactant, emulsification index, surface tension.

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Evaluation of antimicrobial potentials of stem bark extracts of Erythrina senegalensis DC

James Hamuel Doughari

Abstract: Antimicrobial activity of organic (methanol and chloroform) and aqueous stem back extracts of Erytrina senegalensis against some pathogenic microorganisms was investigated using the filter paper disc diffusion method. Phytochemical studies revealed the presence of saponins, tannins, glycosides, phenols and alkaloids. The extracts demonstrated antimicrobial activity against both bacteria (Staphylococcus aureus, Streptococcus pyogenes, Escherichia coli, Salmonella typhi, Pseudomonas aeruginosa) and fungi (Aspergillus flavus, Aspergillus fumigatus, Candida albicans, Penicillium notatum). For the bacteria, the highest activity (14 mm zone diameter of inhibition) was demonstrated against E. coli and the lowest activity (4 mm zone diameter of inhibition) against S. aureus and P. aeruginosa, while for the test fungi, the highest activity of 8 and 6 mm (zone diameter of inhibition) was demonstrated against C. albicans and A. flavus respectively, and the lowest activity of 4 mm against P. notatum. The methanol extracts demonstrated the highest activity while, the aqueous extracts demonstrated the lowest activity against all the test organisms. The activity of the extracts increased with increase in temperature (4 - 100ºC) and acidic pH, but decreased as the pH was adjusted toward alkalinity (pH 8 - 10). The MIC (7.5 - 30 mg/ml) and MMC (8.0 - 30.0) for bacteria, and MIC (7.5 - 40) and MMC (8.0 - 30.0) shows that E. senegalensis stem bark, if further purified can be used to source novel antibiotic substances for drug development against infections such as typhoid fever, urinary tract and wound infections, dysentery and mycotic infections.[...] Read More.

Keywords: Antimicrobial activity, antibiotic substance, bacterial infections, disc diffusion method, Erythrina senegalensis, phytochemicals, MIC, MMC, mycotic infections.

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Influence of physical and chemical mutagens on dye decolourising Mucor mucedo

Bhargavi Moturi* and M. A. Singara Charya

Abstract: The decolourisation efficiency of the wild fungal strain Mucor mucedo was investigated by the treatment with physical mutagen ultraviolet radiation (UV) and chemical mutagens [ethyl methyl sulfonate (EMS), diethyl sulfonate (DES) and colchicines]. The mutants that were exposed to 12 and 15 min UV radiation showed reduction in extension and branching of hyphae. EMS at concentrations of 100 and 150 mg inhibited the germination of spores in M. mucedo. Surprisingly, at concentrations of 100 and 150 mg DES, spores were converted to yeast like cells which produced buds instead of hyphae. Colchicine at higher concentrations abolished the germ tube and hyphal elongation. There was stimulatory effect on growth at lower concentrations only. With respect to enzyme productions and decolourisation activity, there was increase in protease (1.48 U/ml) and peroxidase (1000 U/ml) production in Mucor mucedo when exposed to 9 min UV radiation and showed maximum decolourisation activity of crystal violet (90%) and malachite green (70%). There was an increase in the peroxidase enzyme (1200 U/ml) production at 50 mg concentration relating to the maximum decolourisation activity of crystal violet (90%) and malachite green (71%). Also, there was a decrease in the production of all enzymes in Mucor mucedo when treated with different concentrations of DES and so, there was no improvement in decolourisation activity. There was an increase in protease (1.86 U/ml) and peroxidase (1000 U/ml) production only at 10 mg concentration of colchicine proving that the higher enzymatic secretions were responsible for the decolourisation efficiency of 89% in crystal violet and 74% in malachite green. The wild strain isolated from dye effluent amended soils when exposed to different physical and chemical mutagens showed improvement in the decolourisation of crystal violet and malachite green except in the case of DES.[...] Read More.

Keywords: Mucor mucedo, ultraviolet radiation, ethyl methyl sulfonate, diethyl sulfonate, colchicine, protease, peroxidase, laccase, decolourisation activity.

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Properties of dehalogenase from Rhizobium sp. RC1

Full Length Research Paper

Abstract: Microorganisms isolated from sawdust have been demonstrated to be effective in its degradation. Eight bacteria and eight fungi were isolated from wet decaying sawdust. These were tested for their capability to degrade sawdust. Among the bacteria, C ellulomonas sp. was found to be the most effective degrading agent based on its high percentage degradation (18.3%). This was followed by Micrococcus sp. (16.0%) and Pseudomonas sp. (14.6%), Cytophaga sp. and Bacillus sp. had the lowest percentage degradation of 0.2 and 7.7%, respectively. The fungi, Penicillium sp. had the highest percentage degradation of 14.3%, followed by Mucor sp. (13.3%) and Trichoderma sp. (9.5%). Aspergillus sp. and Absidia sp. had the lowest percentage degradation of 4.3 and 6.5%, respectively. This report shows that indigenous microorganisms possess the capacity to degrade sawdust.[...] Read More.

Keywords: Degradation, sawdust, utilizing, autochthonous microorganisms.

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Listeria monocytogenes in foods: Incidences and possible control measures

F. Adzitey and N. Huda*

Abstract: The bacterium Listeria monocytogenes is a Gram-positive, intracellular, ubiquitous, and facultative food-borne pathogen of humans and animals. They may occur naturally in environmental sources such as soils, faeces and intestinal tracts of animals and humans. The pathogen causes listeriosis characterized by gastroenteritis, meningitis, abortion, and sometimes death in systemic cases. Neonates, infants, immunocompromised individuals, pregnant women, and the elderly in particular are most susceptible to listeria infections. In recent times, contamination of foods by L. monocytogenes has become a major concern to all stake holders in the food industry and the health sector. Their infection has been associated with a number of food-borne outbreaks resulting from the consumption of various foods especially, cooked and chilled ready-to-eat foods. A review on L. monocytogenes and its association with foods is important to create more awareness on the need to reduce their colonisation, transmission, cross contaminations and infections.[...] Read More.

Keywords: Listeria monocytogenes, listeriosis, food.

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Expression and identification of a small recombinant beefy meaty peptide secreted by the methylotrophic yeast Pichia pastoris

Song-Rong Zeng, Yan-Ping Wang*, Yong-Qing Yang, and Jian Zhang

Abstract: A tasty peptide, beefy meaty peptide (BMP), which was initially isolated from beef digested by papain, has potential as a new flavor enhancer. BMP is a small peptide consisting of eight amino acids. In this study, DNA encoding BMP was synthesized and cloned into the expression vector pPICZ A to obtain the recombinant expression vector pPICZ A-BMP. The recombinant vector was linearized and then integrated into the genome of Pichia pastoris strain X-33 by electroporation. The recombinant strain P.p2 was then incubated in BMGY medium and then induced in BSM medium for expression of BMP. The fermentation broth was centrifuged and the supernatant was purified by gel-filtration chromatography. Purified recombinant BMP was then tested by high performance liquid chromatography- mass spectrometry (HPLC-MS). After optimization of the culturing process, the yield of BMP reached 10 mg/L in the clarified broth. The results of mass spectrometry/mass spectrometry (MS/MS) showed that recombinant BMP secreted from P. pastoris had a molecular weight of 873.7 Da rather than the expected 847 Da. We speculate that the last amino acid, Ala, of the BMP sequence was replaced with Pro in the BMP fragment.[...] Read More.

Keywords: beefy meaty peptide, Pichia pastoris, peptide expression, HPLC-MS.

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Comparative analyses of phytochemicals and antimicrobial properties of extracts of wild Tamarindus indica pulps

Adeola, A.A*, Adeola, O.O. and Dosumu, O.O.

Abstract: Tamarindus indica L. (Tamarind), an underutilised fruit tree which belongs to the Leguminosae family, grows wild in the savannah region of Nigeria. T. indica pulp was obtained from 19 towns of the 20 savannah states of Nigeria. The methanol and hexane crude extracts obtained from it pulps were evaluated in vitro to determine their inhibition activities on human pathogenic microorganisms made up of five bacteria and three fungi. All the bacterial strains were sensitive to both extracts at concentrations ranging from 25 to 125 mg/ml, using the agar broth cup diffusion procedure. Only the hexane extract exhibited intrinsic antifungal properties on Penicillium species. Preliminary phytochemical screening of both extracts indicated the presence of alkaloids and tannins. Both the antimicrobial and phytochemical properties of the extracts of the pulp varied for locations of the tamarind. Natural products present in tamarind pulp have potential of being used as agents for animals and/or plants protector against pathogenic microorganisms.[...] Read More.

Keywords: Tamarind, phytochemical, antimicrobial, underutilised fruit, saponins.

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Nested PCR on semen samples for the detection of Mycobacterium avium subsp paratuberculosis

Ali Sharifzadeh*, Abbas Doosti, Mohammad Hashem Fazeli and Iman Adavoudi

Abstract: Mycobacterium paratuberculosis (MAP) is a gram positive, acid-fast bacterium and cause of Johne’s disease in some animals. The important signs of this disease in bovine are diarrhea, weight loss, bowel inflammation, fever and reduce of milk production. The symptoms of this disease are very similar to Crohn©s disease in humans. The aim of this study was to use nested -PCR as an accurate and fast method to trace MAP in bull semen. Semen samples from 112 bulls were collected and DNA was extracted. Then, nested-PCR was performed by specific primers for IS900 gene of MAP. The PCR products with 230 bp length were estimated as a positive. The frequency of MAP in semen samples were 12.50%. The results were showed nested-PCR is a good procedure with high efficiency for detection of intracellular bacteria such as M. paratuberculosis in bull©s semen samples. Thus, despite this abundance more attention to this disease in bulls to identify MAP quickly is essential.[...] Read More.

Keywords: MAP, nested-PCR, John’s disease, IS900 gene, semen, bull.

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Prevalence of plasmid-mediated 16S rRNA methylase genes among Proteus mirabilis isolates from a Chinese hospital

Fangyou Yu, Jingye Pan, Baixing Ding, Lehe Yang, Xueqing Zhang and Liangxing Wang*

Abstract: 16S rRNA methylase-mediated high-level resistance to aminoglycosides has been reported recently in clinical isolates of Gram -negative bacilli from several countries. Five (2.5%, 5/198) of 198 isolates of Proteus mirabilis from a teaching hospital in Wenzhou, China, were positive for 16S rRNA methylase genes (one for armA, four for rmtB) and highly resistant to gentamicin, amikacin and tobramycin (MICs, 256 g/ml). One of five isolates harboring 16S rRNA methyalse genes were extended-spectrum - lactamases (ESBL) producer. The plasmids harboring 16S rRNA methylase genes from four out of five donors were transferred into the recipients, Escherichia coli J53. Among five isolates harboring armA and rmtB, the armA gene and the rmtB genes were located on the plasmids, as determined by Southern hybridization. The present study investigated the prevalence of 16S rRNA methylase genes in clinical isolates of P. mirabilis in China for the first time.[...] Read More.

Keywords: Proteus mirabilis, 16S rRNA methylase, plasmid.

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