Open Access Original Research Article

Evaluation of Agrobacterium-mediated Transformation of Two Nigerian Cassava (Manihot esculenta Crantz) Cultivars TME 419 and “Okwuoto”

F. A. Nkaa, E. E. Ene-Obong, S. O. Afuape, I. C. Okwuonu, S. S. Kahya, N. J. Taylor

Journal of Advances in Biology & Biotechnology, Page 1-10
DOI: 10.9734/JABB/2015/18603

For efficient transformation of cassava to enhance the productivity of the crop, developing effective protocol for the genetic transformation is necessary. Ten Nigerian cassava cultivars were screened in vitro for production of friable embryogenic callus (FEC) and transformation using Agrobacterium tumefaciens. All the ten cassava genotypes screened produced organized embryogenic structures (OES) on Driver and Kuniyuki Walnut (DKW) medium supplemented with 50 µM picloram between two to four weeks after culture using immature leaf lobes as explants. However, the percentage of OES formation was variety dependent. TMS 96/1632 gave the highest percentage of OES (66%) in comparison to the TMS 60444 that served as control which produced 80% of OES. Conversely, friable embryogenic callus (FEC) production was achieved only in four cultivars – two improved varieties (TMS 96/1632 and TME 419) and two local land races (‘Okwuoto’ and ‘Nwugo’) in comparison to that produced by TMS 60444. In cassava somatic embryogenesis, generation of FEC is very important because they are the target tissues for transgene insertion. The friable embryogenic calli generated by TME 419, ‘Okwuoto’ and the control TMS 60444 were selected and further screened for transformation via Agrobacterium mediated transformation. The Agrobacterium tumefaciens used carried the green fluorescent protein (GFP) as the marker gene. At the end of the transformation process, transgenic calli expressing the GFP gene were recovered from the three genotypes transformed. Regeneration of the transgenic calli into transgenic cotyledons were also achieved among the three genotypes screened but recovery of transgenic plantlets from the cotyledons were only actualized from those of cv. TMS 60444.

Open Access Original Research Article

Remediation of a Model Petroleum Hydrocarbon-polluted Soil after Amendment with Nutrient-rich Sludge Obtained from a Beverage Effluent Treatment Plant in Benin City, Nigeria

Beckley Ikhajiagbe, Chinenye C. Chijioke-Osuji

Journal of Advances in Biology & Biotechnology, Page 1-13
DOI: 10.9734/JABB/2015/19098

The present study investigated the bioremediation of a petroleum hydrocarbon-polluted soil after substrate amendment with nutrient-rich sludge (NRS). Sun-dried top soil was measured into buckets and thoroughly mixed with waste engine oil (WEO) on a weight basis to obtain 5% w/w oil-in-soil. The oil-polluted soil in the buckets were divided into 4 sets of separate treatments including polluted soil only (unamended),  polluted soil + 10 g NPK fertilizer, polluted soil + 5%w/w NRS in soil, and polluted soil + 25%w/w NRS in soil. The fifth set of treatments was oil-polluted NRS only (5%w/w). The control was unpolluted soil, unamended. Decrease in heavy metal components of soil was highest in the 25% NRS-amended soil. Total PAH (TPAH) in NPK-amended soils was higher (923.90 mg/kg) when compared to the unamended polluted soil (458.58 mg/kg); this indicated a lower bioremediation efficiency of 38.66% in the former, compared to 69.55% in the latter. Remediation efficiency in the 25% NRS-amended soil (TPAH=260.12 mg/kg) was 82.73%. Phenathrene was totally remediated in the oil-polluted NRS. Micrococcus varians was the most prevalent bacteria species obtained in the present study, followed by Bacillius subtilis, both being hydrocarbon degraders. The fungi species present were Aspergillus niger, Penicillium sp. Fusarium solani, Mucor sp. and Trichoderma sp. Phytoassessment of the study using Vigna unguiculata, showed improved plant growth response in the NRS-amended oil-polluted soils.

Open Access Original Research Article

Evaluation of the Effect of Crude Extract and Aqueous Fraction of Acacia nilotica Leaves on Haematological Indices and Serum Electrolytes Levels on Diabetic Wistar Rats

Y. Tanko, R. A. Ibrahim, A. Muhammad, E. D. Eze, A. Jimoh, K. A. Mohammed, A. Mohammed

Journal of Advances in Biology & Biotechnology, Page 1-7
DOI: 10.9734/JABB/2015/18350

The aim of this study was to evaluate the effect of crude and aqueous fraction of Acacia nilotica  on  diabetic Wistar Rats. Alloxan at a dose of 150 mg/kg body weight was administered to the rats intraperitoneally to induce diabetes. Thirty rats divided into six groups of five animals (n = 5) each were used for the experiment: Group 1 served as normal control group, Group 2 administered  insulin (6 I.U/kg),Group 3 administered 500 mg/kg of crude extract. Group 4 administered 1000 mg/kg crude extract, Group 5 administered 500 mg/kg aqueous fraction and Group 6 received 1000 mg/kg aqueous fraction of Acacia nilotica. There was no significant change in the haematological indices, serum urea, creatinine and potassium compared to control. However, there was a significant increase (p<0.05) in the serum sodium and chloride levels when compared to control. The result indicated that the crude and aqueous fraction of A. nilotica has no effect on haematological indices, urea, creatinine, potassium. However, the fraction has effect on serum sodium and chloride levels on diabetic rats.

Open Access Original Research Article

Fish Association Dynamics in Three Clearwater and-Blackwater River Systems in the Eastern Delta of Nigeria

John Onwuteaka

Journal of Advances in Biology & Biotechnology, Page 1-16
DOI: 10.9734/JABB/2015/18320

Fish species associations in three rivers, Orashi, Sombriero and New Calabar on the Eastern delta of Nigeria were studied using the presence-absence method. A total of 154 species were reported of which 135 species occurred on the Orashi River; 79 species on the Sombriero River and 63 species on the New Calabar River. A hierarchical cluster analyses identified five association types; a ubiquitous group of the Orashi-Sombriero-New Calabar River cluster making up 31.8% of total species. Other associations identified were the Orashi-Sombriero at 0.65%; the Orashi-New Calabar at 8.4% and Sombriero – New Calabar, co-occurring at 5.2%; of total species. The restricted distributions were identified with 52.6% of fish associations confined to Orashi River while 1.3% were confined to Sombriero River. A Sorenson similarity index shows a higher degree of taxonomic homogenization between Sombriero and New Calabar (0.9) than between either Sombriero and Orashi (0.54) or New Calabar and Orashi Rivers (0.5). The findings in this study are consistent with the hypothesis that fish species diversity is mainly influenced by fine-scale environmental factors such as interconnectivity of rivers and streams. In this regard, the study results agree with interpretations from previous studies of fish assemblage structure where habitat diversity either on a longitudinal or spatial gradient influence fish diversity. The remarkable difference in fish taxonomic richness between the Orashi River and the other two river systems (New Calabar and Sombriero) is evidence that the exclusive interconnection of the catchment areas of the Orashi River and the Niger River during the wet season promotes habitat diversity. Consequently this promotes the mixing of fishes and the sharing of species resulting in the highest species richness being recorded on the Orashi River despite the fact that the three river systems exhibit Blackwater and Clearwater characteristics during the wet season and dry season respectively.

Open Access Original Research Article

Analysis of Methanogen Communities in Anaerobic Membrane Bioreactors and Conventional Anaerobic Digester Systems

D. Hufnagel, S. Chang, J. Zhang, R. Lu

Journal of Advances in Biology & Biotechnology, Page 1-9
DOI: 10.9734/JABB/2015/18655

Aims: Methanogenesis is the terminal step in anaerobic digestion and is often rate-limiting and highly sensitive to environmental changes. The performance of engineered anaerobic digesters depends on methanogenesis, which is often measured indirectly through methane production and COD removal. Quantitative real-time PCR (qPCR) is a culture-independent technique that can be used to quantify populations of methanogenic archaea in anaerobic systems to provide insight into system performance and community dynamics. The aims of this paper is to use a SYBR Green-based qPCR method to quantify methanogenic archaea in a variety of anaerobic digesters as a prerequisite for long-term monitoring.

Methodology: In this study, genomic DNA was extracted from mixed liquor samples from five anaerobic digesters using MO BIO Powersoil DNA Isolation kits. Primers targeted the 16S rRNA gene of different methanogens at the order- and family-level for qPCR using SYBR Green. Comparisons were made between methanogen communities from different bioreactor conditions.

Results: Quantification of methanogens showed hydrogenotrophic dominance (Methanobacteriales and Methanomicrobiales) in all bioreactors treating complex feed despite the general assumption that 70% of methane is produced by acetotrophic methanogens. Furthermore, the acetotrophic dominance found in the acetic acid-fed bioreactor showed an anticipated shift in dominance from Methanosarcinaceae to Methanosaetacea when acetate concentrations decreased.

Conclusions: This study illustrated that qPCR using SYBR Green can be used to quantify the distribution of methanogens in anaerobic bioreactors at the order and family level. Methanogen populations for these bioreactors were presented as well as recommendations for future implementation.