MOSP - Macao Scientific Publishers

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Isolation and characterization of a biosurfactant-producing bacterium from Daqing oil-contaminated sites

Tong Liu, Jumei Hou, Yuhu Zuo*, Sining Bi and Jing Jing

Abstract: Biosurfactants are biodegradable, non-toxic and ecofriendly compounds released by microorganisms. Most of the microorganisms were isolated from contaminated sites by petroleum hydrocarbon and industrial wastes. In this study, a biosurfactant-producing strain was isolated from Daqing oil-contaminated sites in China by enrichment culture, hemolytic activity assay, hydrolyzing oil activity assay, improved degreasing effect assay, and emulsification activity measurement. The strain was identified as Pseudomonas sp. BS1 based on its physiological characteristics and analysis of its 16S rRNA gene sequence. The identified isolate is capable of producing glycolipids or other anionic surfactants as determined in our analysis of a phenotypic assay using CTAB. The biosurfactant was isolated from the culture supernatant and identified as dirhamnolipids (Rha-Rha-C10-C10) by high-performance liquid chromatography–mass spectrometry. The culture filtrate and cell-free supernatant produced by this isolate were found to be highly effective in oil displacement from oil sand, suggesting that the isolate has potential use in enhanced oil recovery.[...] Read More.

Keywords: Biosurfactant, Pseudomonas sp., dirhamnolipids, microbial enhanced oil recovery.

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Isolation and characterization of EST-SSRs in the Ramie

Jian-Hua Chen, Ming-Bao Luan, Shu-Feng Song , Zi-Zheng Zou, Xiao-Fei Wang, Ying Xu, and Zhi-Min Sun

Abstract: In order to develop the more EST-SSRs, 320 ESTs of ramie from NCBI were analyzed. 76 SSR primer-pairs developed from 320 ESTs were tested among 62 ramie individuals, and 27 SSR loci were polymorphic. Among the 27 primers, the numbers of alleles per locus ranged from two to five, in which 19 primers amplify two alleles, seven primers amplify three alleles, and only one primer amplifies five alleles. Observed heterozygosity (HO) of overall loci among the 27 primer pairs ranged from 0.16 to 0.93 and expected heterozygosity(HE) ranged from 0.21 to 0.66.Of the 27 loci, 14 displayed significant deviations from Hardy–Weinberg expectations (P < 0.05). No significant linkage disequilibrium (LD) was detected among the 27 loci. The 27 primers have been used in the ramie molecular linkage map and genetic diversity analysis successfully.[...] Read More.

Keywords: Microsatellite marker, ramie, EST, EST-SSR.

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In vitro assessment of Inula spp. organic extracts for their antifungal activity against some pathogenic and antagonistic fungi

Faten Omezzine*, Mejda Daami-Remadi, Asma Rinez, Afef Ladhari and Rabiaa Haouala

Abstract: Inula viscosa, Inula graveolens and Inula crithmoïdes (Asteraceae) leaf and flower organic extracts (hexane, chloroform and methanol) were assessed for their antifungal activity against two Trichoderma species (Trichoderma harzianum and Trichoderma viride) and three formae speciales of Fusarium oxysporum. I. viscosa organic extracts showed an important inhibitory activity against all target fungal isolates. Growth inhibition percentage ranged between 17-61, 77-100, and 55-100% in presence of hexane, chloroform and methanol I. viscosa leaf extracts, respectively. Flower organic extracts reduced mycelial growth of all fungi by 32-66, 30-75, and 8-70%, respectively. For I. graveolens, Stem + leaf organic extracts showed more or less important inhibition depending on solvent nature, though, flower organic extracts were found to be the most effective against tested fungi: a total inhibition of growth was recorded with methanol fraction against all target fungi and with hexane fraction against F. oxysporum f. sp. melonis (FOM) and T. viride. In presence of I. crithmoïdes leaf organic extracts, a total growth inhibition was noted with the three extracts against T. harzianum, with hexane and methanol fraction against T. viride and with chloroform fraction against FOM. I. crithmoïdes flower extracts caused a highly significant growth inhibition of about 57-100, 66-100, and 100-100% with hexane, chloroform and methanol extracts, respectively. Therefore, I. viscosa, I. graveolens and I. crithmoïdes could be an important source of biologically active compounds useful for developing environmentally safe antifungal products.[...] Read More.

Keywords: Antifungal activity, organic extracts, Inula, radial growth.

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Scrutiny for a disaccharide oxide reductase from filamentous extracellular pathogens

Monica A. Calderon Oropeza*, Raul A. Mendoza Martinez , Georgina Reyna Lopez, Gustavo Santoyo, Alberto Flores Garcia and Mauro M. Martinez-Pacheco

Abstract: World demand to find microorganism producers of enzymes with a potential biotechnological use is increasing daily. Therefore, the objective of this study was to find one or more microorganisms capable of oxidizing sugars. Of the thirteen strains tested AFG2 Colletotrichum lindemuthianum was the one who showed the best results concerning oxidant capacity against a variety of disaccharides. This fungus was selected for the time course of production of an extracellular oxide-reducing enzyme in liquid minimal medium. A disaccharide-oxidizing peak was obtained on the tenth day of incubation. It was found that the oxide-reducing activity is of enzymatic nature given that the extracellular extract is exposed to enzyme inhibitors and various denaturing agents. Additionally, it was possible to visualize the oxide-reducing activity by zymogram which allowed us to identify a band of enzyme activity with a calculated molecular mass of 79.43 kDa. Thus, C. lindemuthianum AFG2 wild fungal isolate is a candidate to study the production of these enzymes under optimized growth conditions that can increase performance.[...] Read More.

Keywords: Colletotrichum lindemuthianum, disaccharide oxide reductase activity relative zymogram.

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Molecular cloning and extracellular expression of cyclodextrin glycosyltransferase gene from Bacillus sp. NR5 UPM

Norhayati Ramli, Suraini Abd-Aziz*, Mohd Ali Hassan, Noorjahan Banu Alitheen, Kamarulzaman Kamaruddin and Zoolhilmi Ibrahim

Abstract: The cloning of a polymerase chain reaction (PCR) gene fragment from Bacillus sp. NR5 UPM isolated from the soil in Malaysia into an Escherichia coli expression vector was successfully carried out. Analysis of the nucleotide sequences revealed the presence of an open reading frame of 2112 bp which encoded a protein containing 704 amino acids with a putative molecular weight of 78.6 kDa. The deduced amino acids sequence showed about 98% homology with the CGTase from Bacillus sp. KC201. Compared to the wild type, the CGTase that was produced in E. coli cells only required one-fourth of culture time and neutral pH to produce CGTase. After 12 h of cultivation, the CGTase activity in the culture medium reached 29.6 U/ml, which was approximately 2.5-fold higher than the CGTase from the parental strain. The CGTase was produced extracellularly by E. coli (94%) indicating the signal peptide was functional in E. coli.[...] Read More.

Keywords: Molecular cloning, nucleotide sequence, cyclodextrin glycosyltransferase, Bacillus sp. NR5 UPM.

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Bacteremia due to multidrug-resistant (MDR) and extended-spectrum beta-lactamase (ESBL) producing Acinetobacter baumannii

Abdollah Bazargani and Zahra Hashemizadeh*

Abstract: Bacteremia due to Acinetobacter baumannii is a common problem in hospitals worldwide. Physicians in the intensive care units (ICUs) encountered a serious challenge of finding a drug to cure the extended-spectrum beta-lactamase (ESBL) producing and multi-drug resistant (MDR) A. baumannii bacteremia. Our aim was to determine the frequency of A. baumannii bacteremia in an Iranian hospital ICUs, their antibiotic susceptibility patterns, and the frequency of ESBLs by a cross-sectional study. A total of 340 patients admitted to ICUs during a 6 month period of study were investigated for bacteremia due to A. baumannii. Bacteria isolates from blood specimens were identified as A. baumannii by API 20NE system. Antimicrobial susceptibility was studied with disk diffusion method. Detection of ESBLs was done by double disk synergy test. Of the 340 patients investigated, bacteremia was found in 114 cases (33%). A. baumannii was diagnosed as the etiological agent of bacteremia in 69 cases (60.5%). All the isolates were multi-drug resistant. Except one, all the remaining isolates (98.6%) were resistant to at least 7 of 13 tested antibiotics. Pandrug-resistance was observed in 4 isolates (5.6%). Of all the isolated A. baumannii, 49 (71%) were found to be resistant to cephalosporins by screening tests and among them 27 isolates (39%) were found to be ESBL producing. Our study showed a high frequency of A. baumannii bacteremia occurrence in our hospital ICUs. An urgent intervention is needed to reduce the MDR bacterial load in these critical units.[...] Read More.

Keywords: Acinetobacter baumannii, bacteremia, multi-drug resistant, extended-spectrum beta-lactamase.

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Identification of some Penicillium species by traditional approach of morphological observation and culture

Suhaib A. Bandh*, Azra N. Kamili and Bashir A. Ganai

Abstract: Ninety six samples of water collected from Dal Lake, Kashmir at eight different sites for a period of one year from April 2010 to March 2011 were tested for the presence of Penicillium species. Five different species of the said genus were isolated from the samples by serial dilution technique. Out of total 122 fungal colonies isolated, five species of Penicillium viz, Penicillium olivicolor, Penicillium commune, Penicillium chrysogenum, Penicillium funiculosum and Penicillium dimorphosporum were obtained. Among the isolated species P. funiculosum was the most abundant (28.7%) followed by P. chrysogenum (27.04%), P. dimorphosporum (23.77%), P. olivicolor (16.40%) and P. commune (4.09%). Maximum percentage of fungal colonies (27.7%) was observed at site PKB followed by TBN (21.13%), DLG and GB (13.15%) each, NL (8.45%), BHN (7.04%), HB (5.63%) and BD (3.76%).[...] Read More.

Keywords: Macroscopic, microscopic, Dal Lake, serial dilution, water, Penicillium.

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Isolation and screening of -glucosidase enzyme inhibitor producing marine actinobacteria

Full Length Research Paper

Abstract: a-Glucosidase enzymes are responsible for hydrolyses of carbohydrates thereby converting dietary disaccharides into absorbable monosaccharide. Inhibitors of such enzymes can be used as clinical tool for treating diabetes. Conventionally such inhibitors are reported from plant and microbial sources. However, microbial inhibitors are considered to be the most important as they are capable of producing micro molecular compounds. Hence the present study was conducted to test actinobacteria for their ability to produce yeast and rat α-glucosidase inhibitors. a-glucosidase inhibitor producing ability of 30 strains of marine actinobacteria was characterized. The strains showed significant inhibitory activity against yeast and mammalian a-glucosidase. Of the 30 strains, only four strains showed significant yeast a-glucosidase inhibitory activity. Among the four, PSG-22 showed 90% significant inhibitory activity. Similarly, six strains showed above 50% of inhibition of mammalian α-glucosidase enzyme in the rat system. Among the six strains, PSG-22 showed significant activity of about 80% inhibition activity. Interestingly strain PSG-22 was looking like an indigenous marine form as it required seawater for its growth.[...] Read More.

Keywords: Actinobacteria, a-glucosidase inhibitor, marine, enzyme inhibitor.

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The prevalence, antibiogram and characterisationof methicillin resistant Staphylococcus aureus among the patients from the Doon Valley hospitals

Sachin Sharma and Anju Mall*

Abstract: In 1880, Staphylococcus aureus was first discovered by a surgeon named Sir Clifton Smithin pus from surgical abscesses in Aberdeen, Scotland. Methicillin, as the first beta-lactamase resistant penicillin, was used to treat S. aureus infection in 1961. The first methicillin-resistant Staphylococcus aureus (MRSA) was identified in the United Kingdom in the same year. It appeared in the United States in 1981 among intravenous drug users. MRSA is an important agent of hospital-acquired infection. Two hundred patients who were admitted in the Doon valley hospitals were screened for nasal colonization of MRSA. Morphological and biochemical identification was also done. Out of 200 nasal samples, 97 S. aureus were recovered. Crome agar was used in order to detect MRSA, only 23 S. aureus were recovered out of total 97 isolates. Antibiotic susceptibility was tested by using the disk diffusion technique on Mueller-Hinton agar. A total of 12 antibiotics were used. Our study reveal the presence of MRSA in the Doon valley hospitals this might also be prevalent in other parts of India as antibiotic misuse is equally common there. This will help in treating this problem in referral hospitals.[...] Read More.

Keywords: Methicillin-resistant Staphylococcus aureus (MRSA), Doon valley, prevalence, antibiotics.

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Enhanced production of mycelial biomass and ganoderic acid in submerged culture of Ganoderma applanatum ACCC-52297 elicited by feeding rutin

Full Length Research Paper

Abstract: In this study, it was found that supplementation of 0.6 g/L rutin could improve the fermentation performance of Ganoderma applanatum ACCC-52297 in terms of mycelial growth and ganoderic acid (GA) production. Albeit retarded mycelial growth was detected at the first 36 h in the submerged culture of G. applanatum ACCC-52297 with the addition of rutin, kinetic model analysis revealed that rutin could improve mycelial growth and GA synthesis at the later phase of the fermentation (after 36 h). As such, rutin post-feeding strategy was proposed to elevate the final GA titer and at the same time minimize the inhibitory effect of rutin on mycelia growth. As a result, higher GA production (293 mg/L) and dry mycelia weight (DCW) (30.5 g/L) were achieved, GA were increased by 102.1 and 7.32%, and DCW were increased by 200 and 130% compared with those culture without addition of rutin and addition of 0.6 g/L rutin at the beginning of fermentation, respectively. Rheology analysis showed that addition of rutin was adversely related with the broth consistency coefficient and apparent viscosity, possibly due to the inhibitory effect of rutin on the biosynthesis of some macromolecules such as proteins and polysaccharides, which could partially account for the improved production of mycelia and GA during G. applanatum ACCC-52297 fermentation. Quericean, a metabolite of rutin, was also found to accumulate within the mycelium. It was concluded that rutin does not participate in the synthesis of GA as a precursor but rather facilitates the synthesis of GA and mycelia biomass by increasing the dissolved oxygen concentration during fermentation.[...] Read More.

Keywords: Ganoderma applanatum, rutin, ganoderic acid, dry cell weight, rheology.

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