Open Access Original Research Article

Optical and Structural Properties of Protein Capped ZnO Nanoparticles and Its Antimicrobial Activity

Amit Kumar Bhunia, Tapanendu Kamilya, Satyajit Saha

Journal of Advances in Biology & Biotechnology, Page 1-9
DOI: 10.9734/JABB/2016/29626

Protein coated ZnO nanoparticles (NPs) are prepared by green synthesis method in egg albumin medium. HRTEM analysis and absorption at~360 nm along with ~ 280 nm indicate the formation of protein coated ZnO NPs. Fluorescence study reveals the tryptophan emission~ 340 nm as well as green and blue emission from protein coated ZnO NPs. FTIR bands of ZnO along with amide bands confirm the formation of protein capped ZnO NPs. XRD spectrum showed hexagonal phase of the NPs. The DLS and Zeta potential measurements showed 34.2 nm hydrodynamic radious of the NPs with negative surface charge having value -13.4 mV. Such nanoparticles showed potential antimicrobial activity against gram negative bacteria.


Open Access Original Research Article

Lecithin Isolated from Melon Seed Oil: Antioxidant Activity

Donatus C. Onah, Obioma U. Njoku, Patrick E. Aba, Jonas A. Onah

Journal of Advances in Biology & Biotechnology, Page 1-7
DOI: 10.9734/JABB/2016/28465

Context: A number of antioxidants have been proposed for certain products; however, little information is available about the efficacy of vegetable oil lecithin as antioxidant in food products.

Aim: The study was designed to extract and study oil from melon seed, then isolate and determine the physicochemical and antioxidant property of crude lecithin from the oil.

Methodology: Oil was extracted from the melon seed according to Association of Official Analytical Chemists (AOAC) standard method and characterized. Lecithin was also isolated from the melon seed oil and its physicochemical properties determined. Then, the antioxidant property of the extracted lecithin was evaluated.

Results: The percentage oil yield was 48.25 ± 2.0%. It had a yellow colour, specific gravity of 0.93±0.01 and viscosity of 66.79±2.0% mm2/sec. Its acid, peroxide, saponification and iodine values were respectively 3.36±0.02 mg KOH g-1, Nil, 140.25±2.5 mg KOH g-1 and 126.90±1.0 mg iodine g-1. The percentage yield of lecithin was 0.20±0.01%. It was found to be dark yellow, fairly soluble in acetone, petroleum ether and chloroform. The antioxidant property test shows that there was a decrease in peroxide values as the concentrations of lecithin increased.

Conclusion: The result suggests that the lecithin has antioxidant activity.


Open Access Original Research Article

Breeding Values of 254 Maize (Zea mays L.) Doubled Haploid Lines under Drought Conditions at Flowering and Grain Filling

A. M. M. Al-Naggar, A. M. A. Abdalla, A. M. A. Gohar, E. H. M. Hafez

Journal of Advances in Biology & Biotechnology, Page 1-15
DOI: 10.9734/JABB/2016/29522

Breeding value is the main parameter of initial screening through top cross analysis as it represents the general combining ability (GCA) effects of individual test line. Two hundred fifty four top crosses were produced as a result of crossing between 254 doubled haploid lines (DHL) developed by inducer technique and the inbred line tester PHDMF. The main objective was to identify the DHL's of high breeding value under drought at flowering and grain filling to be exploited in a breeding program aiming at developing drought tolerant maize hybrids. A split plot design in lattice (16 x 16) arrangement was used with two replications, where three irrigation treatments (well watering; WW, water stress at flowering; WSF and water stress at grain filling; WSG) were allotted to main plots and genotypes (254 top crosses) to sub-plots. A separate analysis of variance of RCBD was also performed under each irrigation treatment. Results suggested the existence of significant (p≤ 0.01) differences among studied DHL's × tester crosses under respective irrigation treatments for all studied traits. For each of the ten studied traits, number of desirable DH lines for GCA effects was identified under WSF and WSG conditions. For grain yield/ha (GYPH), number of desirable DH lines for further exploitation in breeding programs; i.e. those having positive and significant GCA effects was 66 for drought tolerance at flowering and 82 for drought tolerance at grain filling. The best ten DHL's in GCA effects for GYPH were No. 16, 204, 44, 66, 62, 2, 14, 161, 76 and 160 under WSF and 66, 208, 87, 15, 26, 205, 39, 177, 102 and 153 under WSG conditions. It was observed that for a given trait, the rank of doubled haploid lines for GCA effects was the same rank of their top crosses for mean performance.


Open Access Original Research Article

Production, Purification and Characterization of Polygalacturonase from Aspergillus niger in Solid State and Submerged Fermentation Using Banana Peels

Francis Sopuruchukwu Ire, Emmanuel Garba Vinking

Journal of Advances in Biology & Biotechnology, Page 1-15
DOI: 10.9734/JABB/2016/29593

Aims: Pectinases are extracellular enzymes produced by microorganisms which break down pectic polysaccharides of plant tissues into simpler molecules like galacturonic acids. Polygalacturonase catalyzes hydrolysis of α-1,4-glycosidic linkages in polygalacturonic acid producing D-galacturonate. Polygalacturonases are hydrolytic depolymerases with endo and exo activities that are widely used in food and chemical industries. This present study aimed to isolate fungal strain capable of producing polygalacturonase, compare its production in SSF and SmF, optimize the cultural conditions as well as purify and characterize the enzyme.

Study Design: The design adopted to evaluate the influence of cultural conditions on the enzyme production and physicochemical parameters on purified enzyme activity was One-Factor-at-a-Time approach (OFAT).

Place and Duration of Study: Department of Microbiology, Faculty of Science, University of Port Harcourt, Nigeria, between November 2014 and December 2015.

Methodology: A total of 12 fungal strains were isolated from fresh banana peels. The isolates were screened for polygalacturonase producing ability using conventional methods and the isolate with the highest zone of inhibition was selected for further studies. The production of polygalacturonase by Aspergillus niger in solid state and submerged fermentation using banana peels as carbon source were compared and the best was used for further production studies. The effect of cultural conditions on polygalacturonase production by the fungus was evaluated. The crude enzyme was purified using ammonium sulphate precipitation and gel filtration on Sephadex G100 and effect of some physicochemical parameters on purified enzyme activity was also determined using standard methods.

Results: A total of 5 out of 12 fungi isolated from fresh banana peels were found to be pectin degraders. The most efficient isolate was identified as Aspergillus niger based on its colonial, morphological and microscopic examination. Solid state fermentation (SSF) was found to be more suitable (60.20%) for polygalacturonase production by Aspergillus niger compared to the submerged fermentation (SmF) (39.80%). Optimization of process parameters revealed that 48 h of incubation was the optimum for polygalacturonase production in solid state fermentation, while 72 h was observed for submerged fermentation. Supplementation of fructose to the fermentation medium led to increased enzyme production. KNO3 was the best nitrogen source for polygalacturonase production. The enzyme was purified by ammonium sulphate precipitation (75%) and gel filtration on Sephadex G100. The purified polygalacturonase showed a specific activity of 166.67U/mg with 8.59% yield and purification fold of approximately 42. The optimum temperature for polygalacturonase activity was 40°C. The purified enzyme was stable within 20-50°C for 1 h. The enzyme has an optimum pH activity at 5.0 and was stable within the pH range of 4-6. Co2+ strongly stimulated the enzyme activity while Ba2+ showed the highest inhibitory effect on the enzyme activity.

Conclusion: This study has revealed an enhanced production of polygalacturonase by A. niger under solid state fermentation using cost effective agricultural waste (banana peels). Thus, the re-utilization of banana peels as substrate for production of the enzyme by the fungus will minimize the pollution problems their presence may pose to the environment. In addition, the results obtained in this study indicated that the polygalacturonase from A. niger could found immense potential application in industrial sectors and biotechnology.


Open Access Original Research Article

Delimitation of the Pore in Tweety Homolog 1 Channels: A Model-guided Approach

J. P. Reyes, J. R. Castillo-Hernández, M. I. Maldonado-Cervantes, E. Maldonado-Cervantes, A. Rangel López, A. A. Vértiz Hernández, M. García-Rangel

Journal of Advances in Biology & Biotechnology, Page 1-12
DOI: 10.9734/JABB/2016/29145

Tweety homolog proteins have been indicated as ´putative anion channels´, but yet there is some lack of definitive data in this regard. Here, we focused on the human Tweety homolog 1 protein (hTTYH1), and elaborated a model based on residue-coevolution analysis and ab initio principles. This much satisfactory model, was tested through sited-directed mutagenesis of residues, R371 and F394. Mutation of these residues resulted in alterations in ion selectivity and blocker sensitivity, respectively, confirming the predictions from the model. Hence, our results strengthen the idea that these proteins are in fact anion channels. As well, our model can be used to propose further structure-function relationships. Similar approaches can be employed for other channels, which have unknown structure, due to the very technically demanding and sometimes uncertain process of crystallization of membrane proteins for X-ray crystallography.