The effects of iodine on kidney bean starch: Films and pasting properties

In the present study the effect of iodine on the structural characteristics (by infrared spectroscopy and X-ray) of films made from kidney bean starch was evaluated. The pasting properties as affected by iodine and glycerol were also evaluated. Kidney bean starch showed C-type (mixture of A- and B-type) crystalline structure, the conversion of starch into films resulted into reduction in intensity of diffractograms. The starch powder FTIR spectra had peaks centered at 1020 and 995 cm^?1 with a higher intensity at 1020 cm^?1, which is consistent with a partially crystalline material since fully crystalline material show similar intensity peaks centered around 1020 and 1006 cm^?1. Films without iodine showed one main peak centered around 1000 cm^?1 consistent with a disordered state similar to that in gelatinised starch. Iodine addition gradually increased the intensity of the bands around 1020 cm^?1 consistent with the formation of more ordered conformation similar to that in the crystalline material. Iodine encourages the formation of helical structures, however, the formation of crystalline material cannot be inferred. The increasing amounts of iodine up to 0.33% level progressively increased the peak-, through- and breakdown-viscosity. Iodine beyond 0.33% level gradually decreased peak-, trough-, breakdown- and setback-viscosity. Pasting temperature gradually increased with the increase in iodine.     

Short-term culture of myeloid leukemic cells allows efficient transduction by adenoviral vectors

BACKGROUND: Ex vivo gene therapy of acute myeloid leukemia (AML) requires efficient transduction of leukemic cells. Recombinant adenovirus has been reported to be a poorly efficient vector in leukemic cells. We investigated leukemic cell culture as a possible method of improving the efficacy of this vector. METHODS: Leukemic cell lines and primary cultured AML cells were incubated with adenoviral vectors carrying GFP, LacZ, or IL-12 cDNA. Transduction efficiency was evaluated by measuring adenoviral genome copy number and transgene expression in leukemic cells. The expression of the coxsackie/adenovirus receptor (CAR), CD29, CD49e, and CD51/61 was measured, as was the effect of blocking integrin on adenoviral transduction. RESULTS: Increasing the multiplicity of infection (MOI) to 300 plaque-forming units per cell enhanced transduction of leukemic cell lines and to a lesser degree of AML cells. Analysis of adenoviral genome copy per cell showed only a partial correlation between gene transfer efficiency and transgene expression. Culture of AML cells for 3 days prior to adenoviral transduction increased both adenoviral copy number per cell and the percentage of transgene-expressing cells. CD29, CD49e, and CD51/61 but not CAR expression increased in cultured AML cells between days 0 and 3 and integrin-blocking experiments showed inhibition of transduction in two of four AML samples tested. CONCLUSIONS: Efficient ex vivo gene transfer in primary cultured AML cells can be achieved by short-term culture of leukemic cells prior to gene transfer with adenoviral vectors at a high MOI. This effect appears to be at least partially mediated by enhanced integrin expression.     

Morphohistological study of the different constituents of a banana (Musa AAA, cv. Grande naine) embryogenic cell suspension

Five types of cellular aggregates have been characterised in embryogenic cell suspensions of banana (Musa AAA Grande naine cv.). Type I corresponded to isolated cells or to small cell aggregates. Type II were composed of embryogenic cells. Type III can be distinguished from type II due to the presence of peripheral proliferation zones with embryonic cells. Type IV were composed of protodermic masses histologically comparable to proembryos. Type V were nodules composed of a central zone of meristematic cells and of an external zone of starchy cells. Each culture flask of a cell line contained a majority of one of the above-mentioned aggregate types. Histological studies of somatic embryo developement on semi-solid regeneration medium showed that there were close similarities between the initial steps of ontogenesis of the embryos and the different cell aggregates in liquid multiplication medium. It appeared that aggregates II–IV of the suspension belong to the same development continuum which reproduces the initial phases of somatic embryo ontogenesis on semi-solid medium. Type V resulted from the development of type IV, for which ontogenesis is hindered by direct contact with 2,4-dichlorophenoxyacetic acid and the shaken liquid multiplication medium. Type I aggregates probably do not belong to the development continuum but rather correspond to the degeneration of the other types of aggregates in the suspension. The presence of intermediate types in the liquid medium reinforces the hypothesis of a relationship between the aggregates. The aggregates tended to develop through time from a majority of type II or III at the beginning of their culture to types IV–V for older suspensions. Received: 10 August 1999 / Revision received: 8 November 1999 / Accepted: 9 November 1999