Advanced Journal of Microbiology Research

Advanced Journal of Microbiology Research Vol. 2012

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

© 2012 International Scholars Journals

Full Length Research Paper

Drynaria quercifolia (L.) J.Sm: A potential resource for antibacterial activity

M. Kandhasamy¹, K. D. Arunachalam²* and A. J. Thatheyus³

¹Department of Microbiology, PGP College of Arts and Science, Namakkal

²Department of Bio-Technology, SRM University, Chennai.

³PG and Research Department of Zoology, The American College, Madurai.

Accepted 23 July 2012

Abstract

Six different organic solvents such as ethanol, methanol, petroleum ether, hexane, benzene and chloroform were used to extract the bioactive compounds from the rhizome of Drynaria quercifolia to screen the antibacterial activity against infectious disease causing bacterial pathogens such as Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, Salmonella typhi, Salmonella paratyphi A, Salmonella paratyphi B, Salmonella marscence, Staphylococcus aureus and Bacillus subtilis by agar diffusion method. The ethanolic extract of D. quercifolia was more active against 80% of the organisms tested. It was followed by methanolic extract (70%), benzene (50%) and chloroform extract (40%) in inhibiting the growth of the organisms tested. Petroleum ether and hexane extract of D. quercifolia did not show any antibacterial activity against any of the pathogenic bacteria tested. Among the bacteria tested, gram-negative bacteria were more susceptible to the crude extracts compared to gram-positive bacteria. Among gram-positive bacteria, S. aureus was susceptible to ethanolic, methanolic and chloroform extracts whereas B. subtilis was susceptible to methanolic extract of D. quercifolia alone. In the present study ethanolic and methanolic extracts of rhizome of D. quercifolia showed high efficiency of antibacterial activity and gram-negative bacteria were more susceptible to all the extracts tested.

Key words: Drynaria quercifolia, rhizome, crude extract, antibacterial activity.

Advanced Journal of Microbiology Research Vol. 2012

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

© 2012 International Scholars Journals

Full Length Research Paper

In vitro detection and characterization of bacteriocin-like inhibitory activity of lactic acid bacteria (LAB) isolated from Senegalese local food products

Michel Bakar DIOP¹, Robin DUBOIS-DAUPHIN¹, Carine DORTU¹, Jacqueline DESTAIN¹, Emmanuel TINE², and Philippe THONART¹,

¹Centre Wallon de Biologie Industrielle (CWBI), 2 passage des Déportés, B 5030 Gembloux, Belgium,

²Laboratoire de Microbiologie et Génie industrielle, Université Cheikh Anta DIOP, Ecole Supérieure Polytechnique, BP 5085 Dakar, Sénégal

Accepted 9 April, 2012

Abstract

The prevalence of lactic acid bacteria (LAB) in Senegalese local food products was determined to be 10⁹ CFU/g in millet flour and milk products, and 10³ CFU/g in seafood products. These food products are generally preserved by spontaneous fermentation (without addition of starters). Of 220 lactic acid bacteria strains randomly selected from such products, 12 isolates capable of producing bacteriocin-like substances (bac+) were detected. Based on the use of API 50 CH test kits and 16S rDNA sequencing, 11 isolates were characterized as Lactococcus lactis subsp. lactis strains and one as an Enterococcus faecium strain. Nisin- and enterocin B-encoding genes were respectively identified in the bac+ lactococcal strains and the E. faecium strain. Since the bac+ Lc. lactis strains were isolated from different products, it suggests a high potential of growth by these strains in variable ecological environments. Expression of the nisin gene was indicated for one of the lactococcal strains, designated Lc. lactis subsp. lactis CWBI-B1410, which showed the highest in vitro antibacterial activity. An antibacterial preparation prepared from the CWBI-B1410 strain showed many similarities with nisin with regards to its inhibitory effects, heat resistance, protease sensitivity profile, as well as retention time of the antibacterial substances on a C₁₈ column. These results suggest that a nisin-like substance is produced by the CWBI-B1410 strain. This strain has been selected for application as an additional barrier to supplementation with sodium chloride as a means to improve the bacterial quality of fish commodities in Senegal.

Key words: Lactococcus lactis, antimicrobial, bacteriocins, Nisin-like substance.

Advanced Journal of Microbiology Research Vol. 2012

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

© 2012 International Scholars Journals

Full Length Research Paper

Chemical composition, antioxidant and antimicrobial properties of the essential oil of Dacryodes edulis (G. Don) H. J. Lam from Gabon

L. C. Obame^{1, 2}, P. Edou², I. H. N. Bassolé¹*, J. Koudou³, H. Agnaniet⁴, F. Eba² and A. S. Traore¹

Accepted 14 March, 2012

Abstract

The essential oil obtained by hydrodistillation from the resin of Dacryodes edulis (G. Don) H. J. Lam was simultaneously analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC -MS). Twenty four components were identified in the essential oil and the main components were sabinene (21.8%), terpinene-4-ol (19.8%), -pinene (17.5%) and p-cymene (11.3%), respectively. The antioxidant capacity of the essential oil was examined using an in vitro radical scavenging activity test and -carotene-linoleic acid assays. In the 2.2-Diphenylpicrylhydrazyl (DPPH) test system, the IC50 value of D. edulis oil was 68.5 ± 2.29 µg/ml. In the -carotene-linoleic acid test system, oxidation of linoleic acid was effectively inhibited by D. edulis (70.0%). The oil was less effective than butylated hydroxytoluene (BHT). Furthermore, the essential oil was evaluated for its antimicrobial activity using disc diffusion and microdilution methods. The essential oil showed better activity against bacterial species than against yeast.

Key words: Dacryodes edulis, Burseraceae, essential oil, antimicrobial activity; antioxidant activity; gas chromatography-mass spectrometry.

Advanced Journal of Microbiology Research Vol. 2012

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

© 2012 International Scholars Journals

Full Length Research Paper

In vitro anti-bacterial activity of a novel isoquinoline derivative and its post antibacterial effects on Pseudomonas aeruginosa

Piyush Bihari Lal¹, Naresh Kumar³, Tasleem Arif³, T. K. Mandal³, K. Akhilesh Verma¹, G. L. Sharma² and Rajesh Dabur³*

¹BR Ambedkar Centrefor Biomedical Research, Delhi University, Delhi- 110 0072

²Institute of Genomics and Integrative Biology, DU Campus, Delhi-110007.

³Regional Research Institute (Ay), Nehru Garden, Kothrud, Pune – 411 038.

Accepted 15 March, 2012

Abstract

The isoquinolines are of great importance to humanity because of their medicinal value and different structure. There have been many researches on the isoquinolines, but relatively few pure compounds have been investigated for their antibacterial activity. The in vitro activity of a novel synthetic antimicrobial compound 1-(4-choloro-phenyl)-6,7-dimethoxy-2-methyl-1,2,3,4,- tetrahydroisoquinoline was evaluated against Pseudomonas aeruginosa (ATCC27853) using standard methods approved by Clinical and Laboratory Standards Institute. The minimum inhibitory concentration of the compound which inhibited more than 90% growth (MIC90) of P. aeruginosa was found to be ranged from 24.0 to 6.0 g ml-1 in different media. The ET50 (concentration which lyses 50% erythrocytes) of the compound was observed to be 450 g ml-1. It was found that the compound down-regulated the expression of PQS, elastase and pyocyanin, the important virulence factors of P. aeruginosa. Proteomics studies revealed that the compound inhibited/down regulated the expression of PhnA and oprL proteins of P. aeruginosa which are crucial for PQS synthesis and membrane integrity. This type of compounds may provide avenue for the discovery of clinically useful antibacterial drugs.

Key words: Isoquinoline, P. aeruginosa, virulent factors, antimicrobial activity, proteomics.

Advanced Journal of Microbiology Research Vol. 2012

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

© 2012 International Scholars Journals

Full Length Research Paper

Biodegradation of hydrocarbons in untreated produce water using pure fungal cultures

C. C. Okoro

Department of Biological Sciences and Biotechnology, Caleb University, Lagos, Nigeria. E-mail: [email protected]. Tel: 08033072754, 01-7430285.

Accepted 8 August, 2012

Abstract

Biodegradation studies of hydrocarbons in untreated produce water from an oil production facility in Nigeria were undertaken over a period of time using pure fungal cultures (Penicillium sp. and Aspergillus niger). The rate of reduction in some petroleum hydrocarbon fractions, such as n-alkanes, aromatics, nitrogen, sulfur and oxygen (NSO)-containing compounds and polycyclic aromatic hydrocarbons (PAHs), were monitored by means of gas chromatography and mass spectrometery, using mechanically treated produce water as a reference. Gas chromatographic analysis showed that untreated produce water with an oil and grease content of 1407 mg/l contained various petroleum hydrocarbon fractions, including n- alkanes (608 mg/l), aromatics (13.88 mg/l), NSO compounds (12.68 mg/l) and PAHs (0.833 mg/l). Upon mechanical treatment, the oil and grease content of the produce water was reduced to 44 mg/l, while n-alkanes, aromatics, NSO compounds and PAHs were reduced to 38.4, 2.65, 1.78 and 0.0655 mg/l, respectively.A pure culture of Penicillium sp. reduced the oil and grease content to 72.3 mg/l, comprising of n-alkanes (65.50 mg/l), aromatics (0.98 mg/l), NSO compounds (1.64 mg/l) and PAHs (0.0021 mg/l) after 120 days of exposure. However, A. niger reduced the oil and grease content to 59.1 mg/l, comprising of n-alkanes (56.50 mg/l), aromatics (0.65 mg/l), NSO compounds (0.96 mg/l) and PAHs (0.008 mg/l) after 120 days of exposure. The results indicate that produce water is readily biodegradable and that fungal cultures have the capability to degrade the recalcitrant PAH component of the petroleum hydrocarbon mixture in produce water. Biodegradation rates were, however, slightly more enhanced by using A. niger than Penicillium sp.

Key words: Biodegradation, fungal cultures, petroleum hydrocarbons,produce water.

Advanced Journal of Microbiology Research Vol. 2012

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

© 2012 International Scholars Journals

Full Length Research Paper

Purification and properties of a non-stereospecific dehalogenase enzyme E (DehE) from Methylobacterium sp. HJ1

Ng Hong Jing¹, Fatin Hanani Sulaiman¹, Roswanira Ab. Wahab², Rolando V. Pakinging Jr. ³, Noor Aini Abdul Rashid¹ and Fahrul Huyop¹*

¹Industrial Biotechnology Department, Faculty of Biosciences and Bioengineering, University Technology Malaysia, 81310 Skudai, Johor, Malaysia.

²Chemistry Department, Faculty of Science, University Technology Malaysia, 81310 Skudai, Johor, Malaysia.

³SouthEast Asian Fisheries Development Center Aquaculture Department, Tigbauan, Iloilo, 5021 Philippines.

Accepted 12 June, 2011

Abstract

The bacterial isolate HJ1, which was identified as a Methylobacterium sp., grew on 2, 2-dichloropropionic acid as the sole carbon source and produced a 2-haloalkanoic acid hydrolytic dehalogenase. This non-stereospecific dehalogenase E (DehE) catalysed the hydrolytic dechlorination of 2, 2-dichloropropionic acid and D, L-2-chloropropionic acid to produce pyruvate and lactate, respectively. The enzyme was purified to homogeneity and characterized. The molecular weight was 36 kDa by SDS-polyacrylamide gel electrophoresis and 72 kDa by gel filtration, suggesting that the enzyme is a protein dimer. The purified enzyme was only inhibited by HgSO4 and was non-stereospecific to haloalkanoic acids. The Km value for the hydrolysis of 2, 2- dichloropropionic acid was 0.25 mM. The enzyme removes chloride present on the -position, but not on the -position, of a number 2–carbon alkanoic acids.

Key words: haloalkanoic acid, dichloropropionate, 2, 2-dichloropropionic acid.