MOSP - Macao Scientific Publishers

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Virulence gene expression, proteins secreted and morphological alterations of Vibrio parahaemolyticus and Vibrio alginolyticus in response to long-term starvation in seawater

Fethi Ben Abdallah,*, Ali Ellafi, Rihab Lagha, Héla Kallel and Amina Bakhrouf

Abstract: In this study, we incubated Vibrio parahaemolyticus and Vibrio alginolyticus (marine food-borne pathogens bacteria) in seawater for 8 months to study their morphologic, proteomic and genetic responses to starvation. The atomic force micrographs of stressed strains showed a reduction of the cells size and an evolution to two coccoid-shape forms whose length is less than 0.4 m and between 0.5 and 1 m. Extracellular protein patterns and gelatinase profiles of stressed bacteria were also altered. Indeed, these modifications were manifested by the appearance and/or disappearance of bands as well as in the level of expression of certain proteins. In addition, we also searched for the presence of eight Vibrio cholerae virulence genes: toxR, toxS, toxRS, ctxA, zot, ace, toxT, and Virulence Pathogenicity Island (VPI) in the genome of investigated strains. The expression level of VPI gene studied by reverse transcriptase polymerase chain reaction was decreased, whereas the mRNA quantities of toxR, toxS, and ace in starved Vibrio remained stable.[...] Read More.

Keywords: Vibrio, seawater, alterations, morphology, proteins secreted, virulence gene expression, RT-PCR.

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Microfungi associated with surface soil and decaying leaf litter of Quercus serrata in a subtropical natural oak forest and managed plantation in Northeastern India

G. Sharma, R. R. Pandey* and M. S. Singh

Abstract: Fungi play a major role in forest functioning by regulating the process of litter decomposition and nutrient release and are sensitive to management practices. Species richness and abundance of fungi in surface soil and decaying leaf litter of Quercus serrata were compared between a subtropical natural mixed oak forest and a managed oak plantation in the eastern Himalayan region. During 12 months of study a total of 106 fungal species were isolated from soil by dilution plate method and decomposing litter by leaf dilution, washed disk and moist chamber methods. Month of samplings and study sites influenced the species composition of soil and litter fungi. Total species richness of soil fungi was significantly (P < 0.05) lower during different seasons in managed plantation than in the natural forest. Dominant soil colonizers from both sites were: Cladosporium cladosporioides, Clonostachys rosea f. catenulata, Fusarium oxysporum, Penicillium indonesiae, Penicillium turbatum, Trichoderma sp. and Trichoderma koningii. Different soil and litter fungi showed differential seasonal preferences at two study sites. Type of fungal species recovered from leaf litters was influenced by the isolation method. Total number of litter fungi isolated from both sites was broadly similar, whereas the species compositions were different. Litter fungi between the two sites showed the highest similarity index in winter, while the similarity of soil fungi was high during summer. The management practices at plantation site had no significant effect on species richness of litter fungi although soil fungal diversity was significantly reduced indicating the role of intensive management practices on soil fungal population.[...] Read More.

Keywords: Fungal diversity, species richness, soil, litter, natural oak forest, managed plantation, Northeastern India.

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Extraction and characterization of melanin from Phomopsis: A phellophytic fungi Isolated from Azadirachta indica A. Juss

K. Rajagopal, G. Kathiravan* and S. Karthikeyan

Abstract: A phellophytic fungus Phomopsis (Endophytic fungi residing in the Bark) of Azadirachta indica screened for the presence of melanin on their hyphae using an alkali procedure, yielded a dark brown pigment. The purified pigment was subjected to various chemical and physical tests that are diagnostic for melanin. The pigment responds positively for all the diagnostic tests for melanin. Further study on the nature of melanin was done with a bark fungus. The fungus synthesis and deposits DOPA type of melanin on their hyphae.[...] Read More.

Keywords: Coelomycetes, dark pigment, DOPA melanin, kojic acid, endophyte.

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Serologic evaluation of hepatitis B and D in patients with cirrhosis

Monireh Rahimkhani*, Hossein Khavari-Daneshvar and Sara Jamali

Abstract: Hepatitis D is the important complication in cirrhotic patients. Diagnosis of hepatitis D is based on detection of HBSAg and HDV Ab titer determination. The present research was performed on a number of cirrhotic patients with the aim to assess the prevalence of hepatitis D and B. In present study all the cirrhotic patients who were referred to Gastroenterology and Endoscopy ward of Imam Khomeini hospital during a period of 18 months were included. The level of anti HDV Ab, anti HBS Ab and HBS Ag were determined by method of ELISA (Pishtaz Teb). In this study 60 cirrhotic patients were evaluated. 16 patients were HBS Ag positive with mean age of 51.9 years, and from this group, 13 patients were anti HBC positive with mean age of 53.23 years and from this group, 8 patients were HDV Ab positive with mean age of 49 years. Hepatitis D remains as one of the problems in developing countries. By timely screening of cirrhotic patients for HDV, patients could undergo additional treatments.[...] Read More.

Keywords: Liver cirrhosis, hepatitis D, hepatitis B, HBS Ag, HBC Ab, HDV Ab.

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Identification of scuticociliate Philasterides dicentrarchi from indo-pacific seahorses Hippocampus kuda

Sang Phil Shin, Jee Eun Han, Dennis K. Gomez, Ji Hyung Kim, Casiano H. Choresca Jr., Jin Woo Jun and Se Chang Park*

Abstract: The “indo-pacific seahorses”, Hippocampus kuda which had been reared in one of the private commercial aquaria for exhibition were sent to the laboratory for diagnosis. Feces and intestinal contents from 5 seahorses were examined microscopically and revealed numerous scuticociliates. We identified the species of scuticociliate by light (wet mount) and scanning electron microscopy, PCR (polymerase chain reaction) and sequencing. This paper reports the first identification of scuticociliate Philasterides dicentrarchi from seahorse in Korea.[...] Read More.

Keywords: Indo-pacific seahorse, Philasterides dicentrarchi, scanning electron microscopy, polymerase chain reaction, sequencing.

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Sawdust and digestive bran as cheap alternate substrates for xylanase production

Simphiwe P. Buthelezi, Ademola O. Olaniran* and Balakrishna Pillay

Abstract: Xylanases are a major group of enzymes, mostly produced from microbial fermentation processes, and have wide industrial and biotechnological applications. The production cost of xylanase is the major factor limiting its use, thus indicating the need for low cost production systems for market of this enzyme. In this study, therefore, sawdust and digestive bran were investigated as substrates for xylanase production by Bacillus strains. The xylanase titre ranging between 30.849 to 45.206 nkat/ml and 6.633 to 22.717 nkat/ml was produced by these Bacillus strains, using sawdust and wheat bran as the substrate, respectively. The optimum temperature for the production of xylanase was found to be between 45 and 55°C, while the optimum pH was 8.0 for all the strains tested. The xylanases produced by these Bacillus strains were found to be stable over a wide range of temperature tested (40 to 90°C). Up to 98 and 95% of the initial activity was retained by the crude extract of two of the Bacillus strains tested, while 10.3 to 56% loss in activity was observed for the other isolates after one hour incubation at 70°C. Addition of metal salts or additives to the crude extract was found to inhibit the enzyme activity to a varying degree, with the following order Hg2+> EDTA > Na > Urea > Mg2+ > Ca2+ observed. Findings from this study indicate the potential use of sawdust and digestive bran as cheaper alternatives for the production of xylanases.[...] Read More.

Keywords: Bacillus sp, digestive bran, sawdust, thermostability, xylanase.

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In vitro evaluation of anti-staphylococcal activity of Ganoderma lucidum, Ganoderma praelongum and Ganoderma resinaceum from Pune, India

Abdulghani Ameri*, Jitendra G. Vaidya and Subhash S. Deokule

Abstract: Antimicrobial activity of Ganoderma praelongum, Ganoderma resinaceum and Ganoderma lucidum were evaluated against thirty strains of clinical isolates of methicillin resistant and methicillin sensitive Staphylococcus aureus (MSSA) by the well agar diffusion and microtiter plate dilution. Chloroform, ethyl acetate, methanol, and water were used as extractive solvents. Standard antibiotic disks of methicillin, vancomycin, linezolid, and mupirocin were used for susceptibility testing of the test microorganisms. Maximum activity of crude extracts was exhibited by ethyl acetate. Sesquiterpeoids extract of G. praelongum (35.67 ± 0.62 mm) and minimum inhibitory concentration (MIC) of 0.390 – 6.25 mg/ml. Diterpenoids and triterpenoids displayed moderate activity while polysaccharides IIIa and IIIb showed weak activity. All bacterial strains were resistant to polysaccharides I and II.[...] Read More.

Keywords: Ganoderma praelongum, Ganoderma resinaceum, Ganoderma lucidum, Staphylococcus aureus, antimicrobial activity.

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Determination of the minimum inhibitory concentrations (MICs) and the minimum bactericidal concentrations (MBCs) for a novel antibiotic

Chen Xiaoxi

Abstract: A novel antibiotic had a wide range of antibacterial spectrum. It was very stable to heat and to acid and alkali. In addition, the effects of storage on the antibiotic had not been observed even after it had been placed in a 37°C thermostat for up to four weeks. The MICs for the antibiotic against eleven strains of bacteria had been determined. Also, the determinations of the minimum bactericidal concentrations (MBCs) against four bacteria were conducted. The antibiotic-producer (Bacillus subtilis) was no better in tolerating its own antibiotic than all the non BS-producers tested.[...] Read More.

Keywords: Antibiotic, stability, minimum inhibitory concentrations (MICs), minimum bactericidal concentrations (MBCs).

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Antibacterial effects of Oradex, Gengigel and Salviathymol-n mouthwash on dental biofilm bacteria

F. H. AL-Bayaty*, T. B. Taiyeb-Ali, M. A. Abdulla and Z. B. Mahmud

Abstract: Three mouthwashes Gengigel, Oradex and Salviathymol N, were tested using experimental microorganisms included Fusobacterium nucleatum, Streptococcus mitis, Streptococcus constellatus, Eikenella corrodens and dental plaque. Staphylococcus aureus and Escherichia coli were used as internal controls. Antibacterial activity was done by diffusion test. Minimum inhibitory concentration test and assessment of bacterial morphology was carried out using scanning electron microscopy (SEM). Results showed that Oradex had a higher antibacterial effect, followed by Salviathymol N; Gengigel mouthwash have weak antibacterial effects against tested microorganisms and dental plaque. SEM observations demonstrated that chlorhexidine exhibited obvious changes in that most of the bacteria loss their original shape and became irregular. The cell also shrunk, became reduced in size. Salviathymol N showed some significant changes while Gengigel failed to exhibited changes on the bacterial morphology of the tested microorganisms. In conclusion Oradex and Salviathymol N can be used as antibacterial mouthwash for chemical plaque control. Gengigel demonstrated weak antibacterial effects which could not be recommended as anti-dental plaque agent.[...] Read More.

Keywords: Gengigel, Oradex, Salviathymol N, Dental biofilm.

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Antimicrobial potential of Xylaria polymorpha (Pers.) Grev.

Nurcihan Hacioglu, Ilgaz Akata and Basaran Dulger*

Abstract: The ethanolic extracts obtained from the macrofungus Xylaria polymorpha (Pers.) Grev. (Ascomycetes) have been investigated for their antimicrobial activity. Growth inhibition using agar disc diffusion assays was determined against Escherichia coli ATCC 11230, S. aureus ATCC 6538P, Pseudomonas aeruginosa ATCC 27853, Proteus vulgaris ATCC 8427, Bacillus cereus ATCC 7064, Micrococcus luteus CCM 169, Candida albicans ATCC 10231, Rhodotorula rubra DSM 70403, Geotrichum capitatum ATCC 28576, Debaryomyces hansenii DSM 70238, Kluyveromyces fragilis ATCC 8608 and Cryptococcus neoformans ATCC 90112. As a result of study, we have found that X. polymorpha revealed antimicrobial activity against all tested microorganisms. Especially, G. capitatum is more susceptible to the extracts.[...] Read More.

Keywords: Xylaria polymorpha, antimicrobial activity.

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