Biotechnology Journal International

Pomegranate (Punica granatum L.) is an ancient fruit crop belonging to the family Punicaceae. Conventionally, pomegranate is propagated through air layering, hard wood and semihard wood cuttings. Recently micropropagation is gaining popularity due to rapid mass propagation of disease free plants in short period of time and small space. Rapid regeneration of plants by micropropagation can be achieved by indirect organogenesis involving induction of callus with exogenous application of plant growth regulators.  In the present study nodal segment was found superior for induction of callus when cultured on MS basal medium consisting of BAP 5 mg/l + NAA 0.4 mg/l. Early shoot initiation, more number of shoots per explant and maximum shoot length was noticed when proliferated calli were cultured on MS basal medium containing BAP 2 mg/l + NAA 0.1 mg/l + GA₃ 0.5 mg/l. Early in vitro root initiation, highest per cent rooting and maximum number of roots per plantlet were recorded when microshoots were cultured on full strength MS medium supplemented with IBA 3 mg/l. RAPD marker analysis revealed 90.66 and 9.33 % monomorphic and polymorphic bands, respectively among tissue culture regenerated plantlets of pomegranate.

This study was set to detect the A and B subunit of Diphtheria toxin gene among patients with pharyngitis and to identify which of the possible biovars is endemic in Kaduna State. The result of standard collection of twenty-two (22) throat swab samples of patients using standard technique of purposive sampling, packing in sterile water at 4°C and DNA extraction using the phenol/ chloroform extraction method gave two 2 (9%) positive PCR samples out of the twenty-two, (22) throat swabs analysed; both A and B subunits of the gene’s amplicon were identified at 248bp and 297bp respectively. Sanger’s (dye-terminator) sequencing of one of the genes’ two, 2 subunits yielding two sequences obtained in the fasta format for bioinformatics analysis using the blast tool at the NCBI website. The 2 subunits of the gene were homologous to the biovars gravis and mitis complete coding sequence gene of Corynebacterium diphtheriae biovar mitis and gravis strains with percentage identity of 97 to both strains. Mutation in the 2 subunits of genes was also noticed with a total of 8 gaps that signify indels.

This study examined the effects of different length of fermentation and storage media on quality characteristics of palm oil produced at the processing centre of Department of Agricultural and Bio-Environmental Engineering, The Federal Polytechnic, Ado-Ekiti, Nigeria. Fresh palm fruits were collected immediately after harvesting and divided into three samples. Each sample was processed into palm oil at intervals of three days and the respective palm oil obtained from each sample was subjected to laboratory test under the same conditions to determine their respective saponification values, moisture content, free fatty acid values and thiobabituric acid number (TBA). Samples were also stored in media such as tin, rubber and glass and their chemical properties were determined after 18 days of storage. The result shows that free fatty acid (FFA) increases with increase in day of fermentation of the palm fruits for both freshly processed oil and those stored for 18 days. Only the oil processed in the first day have the moisture content which are within the 0.01-0.04% standard moisture content values of palm oil while the oil stored in glass had the lowest saponification value of 202.97mgKOH/g and TBA values which are within the standard values of 0.1 to 0.2.

Aim: To analyze various single subunit DNA dependent RNA polymerases and identify conserved motifs, active site regions among them and propose a plausible mechanism of action for these polymerases using the T7 RNA polymerase as a model system.

Study Design: Bioinformatics, Biochemical, Site-directed mutagenesis and X-ray crystallographic data were analyzed.

Place and Duration of Study: Department of Molecular Microbiology, School of Biotechnology, Madurai Kamaraj University, Madurai – 625 021, India, from 2010 to 2013.

Methodology: The advanced version of Clustal Omega was used for protein sequence analysis of  various SSU DNA dependent RNA polymerases from viruses, mitochondria and chloroplasts. Along with the conserved motifs identified by the bioinformatics analysis and with the data obtained by X-ray crystallographic, biochemical and site-directed mutagenesis were also used to confirm the possible amino acids involved in the active sites and catalysis of these RNA polymerases.

Results: Multiple sequence analyses of various single subunit (SSU) DNA dependent RNA polymerases from different sources showed only a few highly conserved motifs among them, except chloroplast RNA polymerases where a large number of highly conserved motifs were found. Possible catalytic regions in all these polymerases consist of a highly conserved amino acid K and a ‘gate keeper’ YG pair. In addition to, these polymerases also use an invariant R at the -4 position from the YG pair and an invariant S/T, adjacent to the YG pair.  Furthermore, two highly conserved Ds are implicated in the metal binding site and thus might participate in the catalytic process. The YG pair appears to be specific for DNA templates as it is not reported in RNA dependent RNA polymerases.

Conclusion: The highly conserved amino acid K, the ‘gate keeper’ YG pair and an invariant R which are reported in all DNA polymerases, are also found in these DNA dependent RNA polymerases. Therefore, these RNA polymerases might be using the same catalytic mechanism like DNA polymerases. The catalytic amino acid K could act as the proton abstractor and generate the necessary nucleophile at the 3’-OH and the YG pair, R and the S/T might involve in the template binding and selection of nucleoside triphosphates (NTPs) for polymerization reactions. The two highly conserved Ds could act as the ‘ NTP charge shielder’ and orient the alpha phosphate of incoming NTPs for reaction at the 3’-OH growing end.

Intraspecific hybridization studies were carried out in two strains of Heterobranchus bidorsalis obtained from two ecological zones in Nigeria – Yola (Sudan savannah) and New Bussa (Guinea savanna) with the aim of evaluating the fecundity, percentage fertilization, hatchability, growth rate and survival rate pure breeds and hybrids of both strains. The study was conducted in triplicates for a period of 56 days. Heterobranchus bidorsalis strains obtained from Yola had higher fecundity compared to the New Bussa broodstock. The average number of eggs in one gram obtained from female Yola broodstock (680) was significantly greater than those obtained (per gram) from the female New Bussa broodstock (647). The mean weight of female broodstock obtained from Yola was 7.8 kg while that from New Bussa was 2.5 kg, with a mean total length of 102 cm and 75 cm respectively and a total weight of 400 g and 160 g of stripped eggs. The pure breed (NN♀ x NN♂) and hybrid (NN♀ x YY♂) both had the highest percentage fertilization (30%). The highest percentage hatchability was recorded in the pure breed (YY♀ x YY♂) with 74.43%. In terms of weight (8.80 g) and length (7.22 cm), the pure breed (YY♀ x YY♂) had the best growth performance than the other crosses. YY♀ x NN♂ hybrid had the least growth rate in terms of weight (6.73 g) and length (4.70 cm). There were significant differences (p<0.05) between the specific growth rate (SGR) in the treatments with an average of 5.2%/day. The pure breed (NN♀ x NN♂) had the lowest survival rate (46.7%) and 80% was the highest percentage survival as recorded in the hybrid (NN♀ x YY♂).