Fixed-bed column study for the remediation of the bauxite-liquid residue using acid-activated clays and natural clays.

Large amounts of bauxite-liquid residue are generated during the production of aluminium, which has detrimental effects on human and environmental health. Currently, the primary goal of every alumina industry is to improve the wet disposal of bauxite-liquid residues into the environment using eco-friendly and cost-effective methods. Therefore, this study investigated the possibility of treating bauxite-liquid residue with natural clays (NCs) and acid-activated clays (AACs) using a fixed-bed column adsorption study. The chemical compositions and functional groups of clays and bauxite were studied using X-ray diffractometry (XRD), X-ray fluorescence (XRF), and Fourier transform infrared spectroscopy (FTIR) techniques. For iron adsorption, breakthrough curves were plotted by varying the adsorbent type in the fixed-bed column. The Bohart-Adams, Thomas, and Yoon-Nelson models were successfully fitted with the breakthrough curves. Two regeneration cycles revealed high regeneration efficiencies for both natural and acid-activated clays. Overall, the study found that AACs were the best candidates for treating bauxite-liquid residue when compared to NCs. For instance, the pH, temperature, electrical conductivity, total suspended solids, total dissolved solids, biochemical oxygen demand, turbidity, and total alkalinity of the bauxite-liquid residue were all significantly decreased below tolerance levels by using AACs. The AACs removed 92% of the iron in the bauxite-liquid residue. Lastly, our research shows that AACs can be used as an adsorbent to treat bauxite-liquid residue, making it less hazardous when it is disposed of into the environment.

Genetic diversity and structure of Capsicum annuum as revealed by start codon targeted and directed amplified minisatellite DNA markers.

BACKGROUND: Identification of high resolving DNA-based markers is of paramount importance to unlock the potential of genetic diversity and selection of unique accessions of Capsicum annuum L., within Cross River and Ebonyi States of Nigeria, for breeding and conservation. Therefore, we comparatively explored the effectiveness of start codon targeted (SCoT) and directed amplified minisatellite DNA (DAMD) markers for diversity analysis of the accessions. Fifteen accessions were collected for DNA extraction and amplifications with the markers. RESULTS: Dendrograms from SCoT and DAMD categorized the accessions into five and three genetic groups, respectively, while the principal component analysis identified five genetic clusters, each from the markers. The average values of allele, gene diversity and polymorphic information content detected with SCoT and DAMD demonstrate that the two markers were effective and efficient, especially, SCoT in genetic diversity study of the accessions of pepper. Number of polymorphic loci (NPL) and percentage polymorphic loci (PPL) from SCoT (NPL = 64, PPL = 80.00-95.73%) and DAMD (NPL = 56, PPL = 53.33-86.67%) were high, but higher in SCoT markers. Other effective genetic parameters (effective number of alleles, Nei's genetic diversity and Shannon's information indices) identified with the two marker systems elucidated the allelic richness, rich genetic diversity within the populations and informative nature of the markers, especially SCoT. The intraspecific genetic diversity, interspecific genetic diversity, and coefficient of differentiation obtained with SCoT and DAMD further exposed the genetic structure with more genetic divergence within than among the populations of the accessions. Estimate of gene flow from the SCoT markers was 3.8375 and 0.6.2042 for the DAMD markers. The estimate of gene flow values from the markers indicated extensiveness with SCoT (Nm = 3.8375) and extremely extensive with DAMD (Nm = 6.2042) among the populations. CONCLUSION: This study shows that SCoT markers may be more useful and informative than DAMD in measuring genetic diversity and differentiation of the accessions of the genus Capsicum. Genetic parameters obtained with SCoT showed that the accessions from Cross River were more genetically diverse than the ones from Ebonyi State. Therefore, SCoT may be a preferred marker in evaluating genetic diversity for improvement and conservation of this spicy crop, C. capsicum.

De novo next-generation sequencing, assembling and annotation of Arachis hypogaea L. Spanish botanical type whole plant transcriptome.

Peanut is a major agronomic crop within the legume family and an important source of plant oil, proteins, vitamins, and minerals for human consumption, as well as animal feed, bioenergy, and health products. Peanut genomic research effort lags that of other legumes of economic importance, mainly due to the shortage of essential genomic infrastructure, tools, resources, and the complexity of the peanut genome. This is a pioneering study that explored the peanut Spanish Group whole plant transcriptome and culminated in developing unigenes database. The study applied modern technologies, such as, normalization and next-generation sequencing. It overall sequenced 8,308,655,800 nucleotides and generated 26,048 unigenes amongst which 12,302 were annotated and 8,817 were characterized. The remainder, 13,746 (52.77 %) unigenes, had unknown functions. These results will be applied as the reference transcriptome sequences for expanded transcriptome sequencing of the remaining three peanut botanical types (Valencia, Runner, and Virginia), which is currently in progress, RNA-seq, exome identification, and genomic markers development. It will also provide important tools and resources for other legumes and plant species genomic research.

Enhancing DNA electrotransformation efficiency in escherichia coli DH10B electrocompetent cells

Electrotransformation also known as electroporation is the most reliable and efficient tool for plasmid DNA uptake. Electrotransformation efficiency is function of many factors which include (1) number of cell washes prior to electroporation, (2) electroporation cell number, (3) electroporation DNA amount, and (4) cell growth phase. Those factors have limitedly been concomitantly investigated in E. coli DH10B strain. This study is aimed to explore above key factors to define the optimal conditions for high electrotransformation efficiency. The results showed that electrotransformation efficiency of E. coli DH10B was enhanced to 1.5 x 10(9) cfu/ug by washing cells three times with 15 ml of 10 percent glycerol. This washed off extra salts from cell suspension and enhanced electrotransformation by preventing arcing and enhancing cell resistance while ensuring minimal level of conductivity. Early exponential phase at 0.15 OD600 was the best growth phase for enhancing electrotransformation of E. coli DH10B. The results also showed that higher electrotransformation efficiency was similarly achieved when 0.5 x 10(10) and 0.6 x 10(10) cell numbers were electroporated with DNA amount ranging from 10 to 40 pg. This study confirmed the optimal conditions for electro competent cell preparation and plasmid DNA electrotransformation, which can result highest transformation efficiency.