Use of Microspore-Derived Calli as Explants for Biolistic Transformation of Common Wheat.

There are specific advantages of using microspores as explants: (1) A small number of explant donors are required to obtain the desired number of pollen embryoids for genetic transformation and (2) microspores constitute a synchronous mass of haploid cells, which are transformable by various means and convertible to doubled haploids therefore allow production of homozygous genotypes in a single generation. Additionally, it has been demonstrated in wheat and other crops that microspores can be easily induced to produce embryoids and biolistic approach to produce a large number of transformants. In view of these listed advantages, we optimized the use of microspore-derived calli for biolistic transformation of wheat. The procedure takes about 6 months to obtain the viable transformants in the spring wheat background. In the present communication, we demonstrated the use of this method to produce the reduced immunogenicity wheat genotypes.

Doubled Haploid Transgenic Wheat Lines by Microspore Transformation.

Microspores are preferred explant choice for genetic transformation, as their use shortens the duration of obtaining homozygous transformants. All established gene-delivery methods of particle bombardment, electroporation, and cocultivation with Agrobacterium tumefaciens were optimized on androgenic microspores or derived tissues. In the biolistic gene delivery method 35-40 days old haploid microspore embryoids were used for genetic transformation, whereas freshly isolated androgenic microspores were used for genetic transformation in the electroporation and Agrobacterium cocultivation-based methods. The genetic transformation methods of biolistic gene-delivery and electroporation gave rise to the chimeric plants, whereas the method involving cocultivation with Agrobacterium yielded homozygous transformants. These methods were tested on a large number of cultivars belonging to different market classes of wheat, and found to be fairly independent of the explant genotype. Other benefits of using microspores or derived tissues for transformation are: (1) a few explant donors are required to obtain desired transformants and (2) the time required for obtaining homozygous transformants is about 8 months in case of spring wheat genotypes and about a year in case of winter wheat genotypes.

Short-term safety and efficacy of calcium montmorillonite clay (UPSN) in children.

Recently, an association between childhood growth stunting and aflatoxin (AF) exposure has been identified. In Ghana, homemade nutritional supplements often consist of AF-prone commodities. In this study, children were enrolled in a clinical intervention trial to determine the safety and efficacy of Uniform Particle Size NovaSil (UPSN), a refined calcium montmorillonite known to be safe in adults. Participants ingested 0.75 or 1.5 g UPSN or 1.5 g calcium carbonate placebo per day for 14 days. Hematological and serum biochemistry parameters in the UPSN groups were not significantly different from the placebo-controlled group. Importantly, there were no adverse events attributable to UPSN treatment. A significant reduction in urinary metabolite (AFM1) was observed in the high-dose group compared with placebo. Results indicate that UPSN is safe for children at doses up to 1.5 g/day for a period of 2 weeks and can reduce exposure to AFs, resulting in increased quality and efficacy of contaminated foods.

Generation of doubled haploid transgenic wheat lines by microspore transformation.

Microspores can be induced to develop homozygous doubled haploid plants in a single generation. In the present experiments androgenic microspores of wheat have been genetically transformed and developed into mature homozygous transgenic plants. Two different transformation techniques were investigated, one employing electroporation and the other co-cultivation with Agrobacterium tumefaciens. Different tissue culture and transfection conditions were tested on nine different wheat cultivars using four different constructs. A total of 19 fertile transformants in five genotypes from four market classes of common wheat were recovered by the two procedures. PCR followed by DNA sequencing of the products, Southern blot analyses and bio/histo-chemical and histological assays of the recombinant enzymes confirmed the presence of the transgenes in the T0 transformants and their stable inheritance in homozygous T1∶2 doubled haploid progenies. Several decisive factors determining the transformation and regeneration efficiency with the two procedures were determined: (i) pretreatment of immature spikes with CuSO4 solution (500 mg/L) at 4°C for 10 days; (ii) electroporation of plasmid DNA in enlarged microspores by a single pulse of ∼375 V; (iii) induction of microspores after transfection at 28°C in NPB-99 medium and regeneration at 26°C in MMS5 medium; (iv) co-cultivation with Agrobacterium AGL-1 cells for transfer of plasmid T-DNA into microspores at day 0 for <24 hours; and (v) elimination of AGL-1 cells after co-cultivation with timentin (200-400 mg/L).

Evaluation of efficacy and safety of a herbal medicine used for the treatment of malaria.

Resistance of Plasmodium falciparum to chloroquine has been reported in several countries. Other anti-malarial drugs in use are expensive and not readily accessible to most people in malaria endemic countries. This has led to renewed interest in the development of herbal medicines that have the potential to treat malaria with little or no side effects. This study obtained a preliminary information on the safety and effectiveness of a plant decoction (AM-1), used in treating malaria. The AM-1 is formulated from Jatropha curcas, Gossypium hirsutum, Physalis angulata and Delonix regia. Patients with suspected malaria attending a herbal clinic were enrolled in the study on voluntary basis. They were hospitalized for treatment, clinical observation, biochemical and haematological monitoring, and parasite clearance while on AM-1. In addition male and female Sprague Dawley rats were used to evaluate the acute and subchronic toxicity effects of AM-1. The AM-1 eliminated malaria parasites (Plasmodium falciparum and Plasmodium malarie) from the peripheral blood of patients with malaria. In addition the AM-1 did not show any undesired effects in the patients as well as in laboratory rats. The AM-1, however, showed differential effect on the activities of selected cytochrome P450 isozymes (7-pentoxyresorufin-O-depentylation, 7-ethoxyresorufin-O-deethylation and p-nitrophenol hydroxylase) in relation to sex of the laboratory rats. These results indicate that AM-1 could be used to treat malaria. However, it could precipitate interactions with other drugs via their biotransformation and elimination. The obtained data warrant further studies in a large number of malaria subjects with monitoring for possible drug interactions.