Open Access Original Research Article

Production and Characterization of Crude 1, 4 - β - endoglucanase by Pseudomonas aeruginosa Using Corn (Zea mays) Cobs and Pawpaw (Carica papaya) Fibres as Substrates

Francis Sopuruchukwu Ire, Dinebari Philip Berebon

Journal of Advances in Biology & Biotechnology, Page 1-16
DOI: 10.9734/JABB/2016/27831

Aims: Lignocellulose is one of the most abundant sources of organic material in the world and it is a polysaccharide which consisted of cellulose, hemicelluloses and lignin. Cellulases are group of hydrolytic enzymes capable of degrading cellulose to smaller sugar components such as glucose units. This study aimed to isolate, screen a suitable 1,4-β-endoglucanase producing bacteria using inexpensive lignocellulosic substrates and optimize conditions for its production as well as characterize the crude enzyme.

Study Design: One-Factor-at-a-Time Methodology (OFAT) was used for culture medium optimization and characterization of crude 1,4-β-endoglucanase from Pseudomonas aeruginosa.

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

Methodology: Soil samples were collected from refuse dump site, cow dung composite soil and forest soil and screened for cellulase production on Bushnell Haas agar medium supplemented with 0.1% (w/v) carboxymethylcellulose (CMC) using 1.0% congo red dye. Isolates were identified using standard cultural, morphological and biochemical methods. Corncobs and pawpaw fibres were evaluated for the enzyme production and optimization of medium and culture conditions in submerged fermentation was investigated for maximum 1,4-β-endoglucanase production. The crude enzyme produced was characterized using standard physiochemical parameters.

Results: Nine (9) out of 21 bacterial strains isolated from soil samples showed positive potential for endoglucanase secretion but only one (1) isolate (CDB4) showing largest clear zone was selected after screening and used for further study. This isolate was identified as Pseudomonas aeruginosa using morphological and biochemical characteristics. Result revealed that the organism was able to secrete the enzyme when corncobs and pawpaw fibres were separately used as carbon sources. The optimal pH and temperature for 1,4-β-endoglucanase production  using  corncob  (3%) was found to be 5.5 and 45°C after 3rd day of cultivation,  while maximum enzyme yield was at 45°C  in pawpaw fibre having pH 6.0  and substrate concentration of 4% after 3rd day of fermentation. The optimum temperature and pH for crude 1,4-β-endoglucanase  activity were at 40°C and 6.5. The crude enzyme was most stable at pH 6.5 and 40°C, uninfluenced across a pH range of 5.5-6.5 and retained over 75% activity at 80°C after 2 h incubation. About 80.84% activity was lost when enzyme was incubated at pH 7. The enzyme was strongly activated by Co2+ and only slightly by Fe2+ and EDTA, while Zn2+, Ca2+, Hg2+ and Mg2+ elicited significant inhibition of the crude enzyme activity with highest repression exhibited by Zn2+.

Conclusion: Results of this study revealed the ability of Pseudomonas aeruginosa to efficiently utilize both corncobs and pawpaw fibres without requirement for expensive pretreatment normally given to lignocellulosic residues. Therefore, this bacterium and its intrinsic metabolic capacity for endoglucanase production using inexpensive substrates at low concentration as well as the high pH stability and thermostability presented by the crude enzyme makes it useful in industrial processes.


Open Access Original Research Article

Combining Ability and Heterosis in Corn (Zea mays L.) Grain Quality and Yield Traits under Different Plant Densities

A. M. M. Al-Naggar, M. M. M. Atta, M. A. Ahmed, A. S. M. Younis

Journal of Advances in Biology & Biotechnology, Page 1-19
DOI: 10.9734/JABB/2016/28127

The objective of this study was to assess mean performance, heterosis and combining ability and their interrelationships in six maize inbreds and their 15 diallel F1 crosses under elevated plant density (D). Three experiments were carried out in each season of 2013 and 2014, using RCBD with 3 replicates; each experiment was assigned to either low-D, medium-D or high-D (47,000, 71,200 and 95,200 plants/ha, respectively). Specific combining ability (SCA)  were higher than general combining ability (GCA) mean squares for GYPP, GYPH, PYPH OYPH and SYPH) under elevated plant density, suggesting the existence of a greater portion of non-additive than additive and variance in controlling the inheritance of these traits, but the opposite was true for grain protein (GPC), grain oil (GOC) and grain starch (GSC). Out of 8 studied traits, significant correlations between means of the parents and their GCA effects existed for 6 traits, namely GPC, GYPP, GYPH, PYPF, OYPF and SYPF under all environments and GOC under high-D. These results indicate that the mean performance   of a given parent for these traits is an indication of its general combining ability. Moreover, significant correlations existed between the means of crosses and their SCA effects in 20 out of 24 cases, suggesting that the mean performance of a cross could be used as an indicator of its SCA effects. For GOC under low-D and medium-D, GSC under low-D and high-D and GPC under low-D, the mean performance of a cross could be used as an indicator of its useful heterosis under the corresponding environments. The useful heterosis of a cross could be used as an indicator of its SCA effects for GOC under low-D and high-D and GPC under medium-D and high-D.




Open Access Original Research Article

Histo-architectural Comparative Analysis of the Hypothalamus of Bat (Eidolon helvum) and Wistar Rat (Rattus norvegicus)

Samsudeen G. Ojuolape, M. Sanni Muritala, Quadri O. Majeed

Journal of Advances in Biology & Biotechnology, Page 1-8
DOI: 10.9734/JABB/2016/27102

Aims: The aim of this study was to compare the histo-architectural variation (if any) on hypothalamus of both Rat (Rattus norvegicus) and Bat (Eidolon helvum).

Study Design:  The histological and histochemical investigations into the hypothalamus of two mammalian species were studied, to determine the possible differences in their thermoregulatory activities.

Methodology: Six (6) rats and six (6) bats were used for this study, the animals were sacrificed under chloroform anaesthesia, after which the skulls of these animals were opened using bone forceps to expose the brains. The hypothalamus were excised from each brain and homogenized to determine the activities of lactate dehydrogenase (LDH), glucose-6-phosphate dehydrogenase (G-6-PDH), acid phosphatase (ACP) and alkaline phosphatase (ALP). The tissue sample of hypothalamus for histological studies were fixed in 10% formol calcium and processed for paraffin wax embedding. Serial sections of 5 μm thickness were stained with Hematoxylin & Eosin, Cresyl fast violet and Gordon & sweet stains. The stained tissues were studied under the light microscope.

Results: The results obtained from the macromorphometric study showed that, there are differences in the body and brain weights of the two mammalian species; bat (275.33±7.49, 3.60±0.09) and rat (193.33±5.30, 2.60±0.08) respectively.  The body weight of bat was observed to be higher than that of rat, and the brain weight of each mammal was found to be directly proportional to its body weight. The histological study showed that, neurones are well distributed in rat compared to bat, while the enzyme activity variables of G-6-PD, LDH and ACP were higher in rat with reliable proportion, except ALP that was found higher in bat (1022.00±0.91) compared to rat (829.75±1.31). This suggested that, the hypothalamus of rat performs more functions of thermoregulation, feeding and circadian rhythm control than bat, since the nuclei of hypothalamus such as; lateral hypothalamic nuleus, arcuate nucleus and suprachiasmatic nucleus control feeding, satiety and circadian rhythm respectively, which could be as a result of differences in their modes of behaviour, habitat and feeding.

Conclusion: Considering the histological analysis and the enzyme activity, the hypothalamus of both animals are significantly different, being influenced by feeding and lifestyles.


Open Access Original Research Article

Analyses of Trypanosoma brucei Phospholipase A2 Structure and Function Using Bioinformatics Approach

Ishaya Yohanna Longdet

Journal of Advances in Biology & Biotechnology, Page 1-8
DOI: 10.9734/JABB/2016/28443

Aim: Studying Phospholipase A2 is increasingly needful because of the enzyme’s biotechnological potentials and involvement in the pathogenicity of Trypanosoma species.  This work was therefore designed to study some of the structural features of putative PLA2 from T. brucei.

Place and Duration of Study: Department of Biotechnology, National Veterinary research Institute, Vom and Department of Parasitology, National Institute of Trypanosomiasis Research, Vom, Nigeria, between July 2015 and May 2016.

Methodology: Bloodstream rat adapted strain of T. brucei was grown in rats and separated using DEAE cellulose chromatography.  Genomic DNA of the parasites was isolated and the PLA2 gene amplified and sequenced (GenBank DB accession number: JN603736). The translated protein structure prediction server PSIPRED, Phyre2 web portal for protein modeling, prediction and analysis, (ProSA) -web, RAMPAGE server, 3DLigandSite and PSI-Blast tool were used to analyse the T. brucei PLA2 translated protein sequence.

Results: The analyses of the PLA2 protein with 447 peptide sequence revealed its secondary structure; 3D structure showing amino acid residues that lie in a helix, strand or coil; ProSA-web z-scores with an overall model quality value of -7.01; the Ramachandran plot that among the 447 residues, 433 (96.86%) were in favoured region; ligand binding site at position 235 (Trp) and its transmembrane helices and membrane topology.

Conclusion: A good quality structural model of Trypanosoma brucei PLA2 was determined and found to be closely related to that of Platelet-activating factor acetylhydrolase.


Open Access Original Research Article

Phytochemical Screening, Nutrient Analysis and Antimicrobial Activity of the Leaves of Lasianthera africana and Dennettia tripetala on Clinical Isolates

R. U. B. Ebana, N. U. Asamudo, C. A. Etok, U. O. Edet, C. S. Onyebuisi

Journal of Advances in Biology & Biotechnology, Page 1-9
DOI: 10.9734/JABB/2016/28291

The spate of resistance to conventional antibiotics is becoming worrisome. As alternatives, plants are investigated for bioactive components with antimicrobial activity. The aim of this study was therefore to investigate the nutrients and anti-nutrients composition, phytochemical components and antimicrobial activity of Dennettia tripetala and Lasianthera africana extracts on clinical isolates. The leaves were screened qualitatively and quantitatively for phytochemicals using aqueous and ethanolic extracts while the antimicrobial activity was done using standard microbiological techniques. The results of the phytochemical screening showed the presence of alkaloids, glycosides, reducing compounds and polyphenol in both plants. Quantification of the phytochemicals showed that polyphenol was the most abundant with values of 17.63% and 14.66% respectively, in D. tripetala and L. africana. Proximate composition in mg/100 g showed that protein was (19.86 - 5.70), fibre (10.80 -13.86), ash (3.16 - 9.28), carbohydrate (49.70 - 73.04) and fat (7.30 each) in both plants, respectively. The anti-nutrients composition in mg/100 g showed the presence of hydrocyanic acid (6.17 - 7.56), soluble oxalate (7.30 - 17.62), total oxalate (17.10-39.70) and phytate (10.19 - 13.20) in both plants. The antimicrobial activity showed that the aqueous and ethanolic extracts of both plants inhibited the growth of Staphylococcus sp, Esherichia coli, Salmonella sp, Shigella sp, Bacillus sp, and Pseudomonas aeruginosa. The highest inhibition (25 mm) was obtained with the ethanolic extract of L. africana on P. aeruginosa. The minimum inhibitory concentration (MIC) of the extracts ranged from 10 mg to 50 mg with        E. coli and Shigella sp being the most inhibited. The findings of the study reveal that the plants are rich in nutrients, phytochemicals and have antimicrobial activity against isolates. Given the results in this study, there is a need to further exploit the antimicrobial potentials of these plants.