This article discusses the maintenance of C. elegans in the laboratory. Topics include the acquisition of worm strains from the Caenorhabditis Genetics Center (CGC), methods of culture and transfer, decontamination of stocks, synchronizing and staging cultures, and procedures for freezing worms for long-term storage and for recovering them from the frozen state.
Genome editing is used to make targeted modifications to the genome of eukaryotic cells. There are many potential applications of genome editing in human pluripotent stem cells (hPSCs) including the generation of knockout and reporter cell lines. This protocol describes a system for efficient genome editing in hPSCs using engineered transcription activator-like effector nucleases (TALENs) or clustered regularly interspaced short palindromic repeat (CRISPR) technology.
Prolonged culture of pluripotent and multipotent stem cells exposes the cells to strong selection pressures, often resulting in genomic alterations. Any genetic manipulation of the cells may further jeopardize their genomic stability. Genomic aberrations affect the differentiation capacity of stem cells, their stem cell identity and their tumorigenicity, and should thus be routinely evaluated for their proper use in basic research and in clinical trials.
The directed differentiation of human embryonic stem cells (hESCs) or human induced pluripotent stem cells (hiPSCs) into hepatocytes could facilitate a rational study of the molecular mechanisms underlying human liver development as well as provide a renewable source of exogenous hepatocytes for drug toxicity testing and cell-based therapeutics. Moreover, if hepatocytes were produced from hiPSCs originating from patients with inborn errors of hepatic metabolism, such cells could be used for modeling liver disease.
The pluripotency of embryonic stem (ES) cells is the result of a highly dynamic equilibrium that is controlled by a complex network of transcription factors that confer unique transcriptional properties to ES cells. Regulation of gene expression appears to correlate with the presence of dual chromatin marks called bivalent domains at the promoters of poised developmental genes. These marks keep differentiation genes silenced but poised and ready to be activated or permanently repressed during differentiation.
A checklist of indigenous pests of cowpea, Vigna unguiculata (L.) at Mokwa, Niger state, Nigeria, and their relative abundance were reported. The impacts of two most commonly used insecticides in the locality, i.e. Dimethoate and Cypermethrin, on cowpea productivity were elucidated. Thirteen insect species were listed, three of which were prominent at the seedling and prereproductive stages. These include: - Ootheca mutabilis, Empoasca dolichi and Medythia quarterna.
Kola is an important cash crop to a significant proportion of Nigerian population who are involved in kola farming, trading and industrial utilization. Research on the improvement of kola productivity and utilization is one of the major mandates of the Cocoa Research Institute of Nigeria (CRIN), where remarkable achievements have been made on kola. CRIN has developed improved Cola nitida hybrids with short maturation period of 5 years and an annual average yield of about 2000 nuts/tree/year.
Pests and diseases have largely contributed to the declining productivity of cocoa in Nigeria. About 25 – 30% loss in yield of cocoa has been attribute to the cocoa mired, Sahlbergella singularis. 17% is lost through the feeding of the cocoa pod borer Characoma strictigrapta while losses attributable to the major disease of cocoa (the black pod disease caused by Phytophtora megakarya) range from 30 – 90% in Nigeria. The estimated farm holdings of peasant farmers account for 90% of the 700,000 hectares of land under cocoa cultivation.
Six acetone extracts of Annona senegalensis root-bark; Tephrosia vogelii root-bark; stem-bark, leaf and seed; Tephrosia candida seed; and two aqueous residue extracts of neem seed kernel and Annona muricata seed kernel were tested for bioactivity against Rasdtrococcus invadens Williams at different concentrations with three replications. The six acetone extracts were highly toxic to adult female R. invadens in the combined mode experiment. T. vogelii stem-bark, followed by its seed; A. senegalensis root-bark and T. candida seeds extracts, was most insecticidal to the mealybug.
Thirteen fixed lines from the cross of FARO 12 and 44 were evaluated at Edozhigi and Gara villages, located in central Nigeria. The trial was conducted to select promising lines to be used for African rice gall midge (AfRGM) and iron toxicity endemic areas. The experiment was randomized complete block design replicated three times. The result showed significant differences in grain yield at Gara but not at Edozhigi. Percentage tiller damage for AfRGM was high in both locations. Iron toxicity score was also moderate for the two locations, however higher scores were obtained at Edozhigi.
