Advanced Journal of Microbiology Research

Advanced Journal of Microbiology Research Vol. 2017

Available online at http://internationalscholarsjournals.org/journal/ajmr

© 2017 International Scholars Journals

Full Length Research Paper

Intra-strain Variation of Lipopolysaccharides from Citrobacter freundii E9750 by in vitro Passages

Rosa E. Reyes^1,2*, Hugo Ramírez Saad³, Julia Pérez³, Enrique Meléndez⁴, Armando Navarro⁵ Chiharu Murata⁶ and Alejandro Cravioto⁷

¹Doctorado en Ciencias Biológicas, Universidad Autónoma Metropolitana Xochimilco-Iztapalapa, México D.F., México.

²Laboratorio de Farmacología, Instituto Nacional de Pediatría, (INP). Secretaría de Salud (SSA), México.

³Departamento de Sistemas Biológicos, División CBS. Universidad Autónoma Metropolitana-Xochimilco, Coyoacán, 04960 México D.F., México.

⁴Departamento de Microbiología y Parasitología. Facultad de Medicina. Universidad Autónoma de México. Coyoacán, 04510 México D.F., México.

⁵Departamento de Salud Pública. Facultad de Medicina. Universidad Autónoma de México. Coyoacán, 04510 México D.F., México.

⁶Departamento de Metodología de la Investigación, Instituto Nacional de Pediatría, (INP). Secretaría de Salud (SSA), México.

⁷International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh.

Accepted 28 May, 2016

Abstract

The genus Citrobacter is closely related to Salmonella and Escherichia coli, and there are some serological cross-reactions existing among these species. These cross-reactivities are caused by O-specific polysaccharide antigens in the LPS, which contain similar epitopes. In some cross-reactive strains, O-specific polysaccharides exhibit structural homology. In order to determinate the frequency of intra-strain variation of lipopolysaccharides (LPS) from Citrobacter freundii E9750 by in vitro passages at two different growth temperatures, isolates obtained from Citrobacter freundii E9750 in vitro passages at 37 and 42°C were analyzed for carbohydrate concentration, reactions to serological tests, and heterogeneity of lipopolysaccharides using SDS-PAGE. The genetic relatedness of the isolates was investigated using the PCR-RFLP profile of rfb and Pulsed Field Gel Electrophoresis (PFGE) profiles. Variation in expression of LPS was observed as a change in the concentration of carbohydrates. In addition, low reactivity with C. freundii E9750 O-antiserum, serological cross reactivity with S. senftenberg O-antiserum, and heterogeneity in electrophoretic mobility, were found. The PFGE and RFLP patterns of all isolates were indistinguishable from each other, including those that presented a serological reaction with the O -antigen sera from S. senftenberg. C. freundii E9750 NCTC isolated strains showed a high frequency in LPS variability. Analysis of the results suggested that heterogeneity was due to changes in the structure of the LPS carbohydrates. Since lipopolysaccharides are important factors in virulence and determine the basis for serotyping, the high frequency of intra-strain O-antigen heterogeneity in C. freundii E9750 is important.

Key words: Lipopolysaccharide, Citrobacter freundii, intra-strain variation, serological cross-reaction, O-antigen, SDS-PAGE, RFLP.

Advanced Journal of Microbiology Research Vol. 2017

Available online at http://internationalscholarsjournals.org/journal/ajmr

© 2017 International Scholars Journals

Full Length Research Paper

Antibacterial potential of leaf extracts of Juniperus communis L. from Kumaun Himalaya

S.C. Sati and Savita Joshi*

Department of Botany, D.S.B. Campus, Kumaun University, Nainital-263002, India.

Accepted 28 May, 2016

Abstract

The sensitivity of five pathogenic multi drug resistant bacteria (Bacillus subtilis, Erwinia chrysanthemi, Escherichia coli, Agrobacterium tumefaciens and Xanthomonas phaseoli) was tested against the crude leaf organic extracts (methanol, ethanol, chloroform and hexane) and aqueous extracts of a Kumaun Himalayan gymnospermous plant Juniperus communis (Cupressaceae), employing disc diffusion method. All the extracts of Juniperus communis were found effective by showing a mark zone of inhibition except aqueous extract. The hexane extract showed maximum inhibition against the test microorganisms (ZOI, 16 – 21 mm) followed by ethanol, methanol and chloroform extract (ZOI, 6 – 17 mm). The inhibitory activity of these extracts was found very effective as compared to Ampicillin (10 mcg) and Erythromycin (15 mcg) standard antibiotics which were used as positive control against these tested microorganisms.

Key words: Kumaun Himalaya, antibacterial activity, Juniperus communis, gymnosperm, crude extract, ampicillin, erythromycin.

Advanced Journal of Microbiology Research ISSN 2736-1756 Vol. 15 (12), pp. 001-007, December, 2016. © International Scholars Journals

Full Length Research Paper

Identification of Thiobacillus thiooxidans CGMCC 10329 and fundamental application in bioleaching as part of a synergic bacterial consortium

Hongfei Zhu^1* and Xuesong Zhao²

¹College of Environmental Science and Engineering and ²Mining School of Liaoning Technical University No. 47 Zhonghua Road, Fuxin, Liaoning 123000, China.

Accepted 12 October, 2016

Abstract    

Bioleaching has become increasingly important in commercial gold extraction because of its economic benefits. Thiobacillus thiooxidans (also known as Acidithiobacillus thiooxidans) is an important participant in synergic bioleaching processes. In this study, a novel strain was isolated from an underground coal mine, identified and named Thiobacillus thiooxidans CGMCC 10329. A consortium of microorganisms including T. ferrooxidans DSM14882, Leptospirillum ferrooxidans CCTCC AB207038 and T. thiooxidans CGMCC 10329 was used to leach four gold ores and four sulfur-containing coal samples; we then determined gold recovery rates and removal rates of elements. The content that may be harmful to the environment, such as sulfur and arsenic contained in the ores, was investigated. The synergic leaching results indicated that the maximum deprivation rates of carbon, sulfur and arsenic were respectively 59.91%, 67.21%, and almost 100%. Bioleaching pretreatment markedly improved the gold recovery rate by 10.7% to 20% in subsequent cyanidation, compared with traditional extraction operations. The average sulfur removal rate by synergic leaching of the four coal samples was 35.4%. This synergic leaching method, to some extent, broadens gold ore resources and benefits the environment by reducing the impact of coal burning.

Keywords: Thiobacillus thiooxidans; synergy; bioleaching; recovery rate; sulfur; deprivation

Advanced Journal of Microbiology Research Vol. 2016

Available online at http://internationalscholarsjournals.org/journal/ajmr

© 2016 International Scholars Journals

Full Length Research Paper

Genetic characterization of osmotolerant fermentative saccharomyces yeasts from Tanzania suitable for industrial very high gravity fermentation

D. Sumari ^1,2*, K. M. M. Hosea¹ and F. S. S. Magingo¹

¹Department of Molecular Biology and Biotechnology, University of Dar es Salaam, Tanzania.

²Ifakara Health Institute, Morogoro, Tanzania.

Accepted 12 February, 2016

Abstract

Naturally occurring yeasts were sought from diverse Tanzanian environments and screened for industrial application. The yeasts were isolated from environments such as traditional brews and wines from various parts of Tanzania. In this regard, a total of thirty yeast isolates were screened for their suitability in Industrial Very High Gravity Fermentation (VHGF). Five of these isolates were able to grow and ferment medium with 40% initial sucrose concentration. Whereby, three were able to grow and ferment medium with 700 g/Litre (70% w/w) initial sucrose concentration. One of the three isolates coded LB2 isolated from a traditional Makonde sorghum brew was able to ferment a medium with initial sucrose concentration of 1000 g/Litre (100% w/w) at 30°C. On the basis of PCR-RFLP of the internal transcribed spacer (ITS) of the ribosomal DNA (rDNA), all the three most osmotolerant isolates were identified to belong to the Saccharomyces sensu stricto clade. Phylogenetic analysis of the 650 bp D1D2 domain of the large subunit 26S rDNA of the isolate LB2 clustered this isolate away from the so far known typical osmotolerant yeasts. The fermentation by LB2 isolate of 100% gravity substrate observed in this work is higher than any other encountered in the literatures reviewed.

Key words: Osmotolerant, PCR-RFLP, Saccharomyces, traditional brews, very high gravity fermentation (VHGF).

Advanced Journal of Microbiology Research Vol. 2016

Available online at http://internationalscholarsjournals.org/journal/ajmr

© 2016 International Scholars Journals

Full Length Research Paper

Susceptibility pattern of pseudomonas aeruginosa against various antibiotics

Farida Anjum¹ and Asif Mir²*

¹Pakistan Council for Science and Technology (PCST), Islamabad.

²Department of Biosciences, COMSATS Institute of Information Technology, Islamabad.

Accepted 7 December, 2015

Abstract

To determine current trends of antibiotic resistance among clinically significant pseudomonas aeruginosa strains causing various nosocomial and community acquired infections. A total of 100 clinical isolates of P. aeruginosa from inpatient and outpatient were studied from June 2008 to May 2009 for its prevalence and susceptibility profiles. Most of the isolates were from pus followed by urine, sputum, blood, ear swab and catheter tip. Uropathogenic P. aeruginosa infections were higher in females than males, ratio was found more among young and elderly debilitated patients. Ciprofloxacin, Piperacillin, Imipenem were found more effective for treatment of infections in outpatients but for inpatients, parental therapy with newer aminoglycosides and third and forth generation cephalosporins need to be advocated as the P. aeruginosa causing nosocomial infections exhibits a high degree of drug resistance. Ninety nine percent of the clinical isolates were resistant to six commonly used antibiotics with highest resistance to ampicillin (100%) and cefuroxime (100%) followed by amoxycillin (99%), co-trimoxazole (99%), Tetracycline (99%), Cefazoline (99%). The in vitro sensitivity pattern of 100 isolates of P. aeruginosa showed highest sensitivity to imipenem (97%) followed by amikacin (79%), tobramycin (70%), ceftazidime (62%), ciprofloxacin (73%), cefoperazone (60%), piperacillin (65%), Gentamycin (34%) and Cefotaxime (14%). ESBLs producing strains (33%) were also less in number but were much more resistant to -lactam and other antibiotics. The results indicate that P. aeruginosa is the most common gram -negative bacterium responsible for the nosocomial as well as community acquired infections. The excessive use of antibiotics has not only led to treat the P. aeruginosa infections but also the emergence of antibiotic resistance. The development of multidrug resistant P. aeruginosa is currently one of the greatest challenges to the effective management of infections. This suggests that in addition to curative measures promptly preventive measures such as hygienic as well as better hospital and postoperative care in administration should be adopted.

Key words: P. aeruginosa, antibiotic resistance, nosocomial infections.