[en] We have applied 'in situ' hybridization technique to examine the expression of two tissue-specific plant genes represented by cDNA clones: pLN-13 and pLN-50 during the symbiosis of 'Lupinus luteus' with 'Bradyrhizobium lupini'. Both genes are expressed in root nodules and their transcripts are restricted to the infected zone of the nodule as revealed with ³⁵S- or ³H-labelled antisense RNA probes. The number of grains over bacteroid-containing cells after hybridization with ³H-labelled probes differed during three tested phases of nodule development: at the 14th, 12st and 28th day after the infection with 'B. lupini'. As control, apical root meristems and segments of root hair zones of uninfected plants were used for incubation with RNA of either sense or antisense orientation preceded by RNAse A digestion. The data obtained confirm that both genes are organ-specific and reveal their developmentally regulated expression pattern during the course of root nodule morphogenesis. (author). 16 refs, 5 figs

[en] The effects of plasmolytically induced symplasmic isolation and AMO-1618 (AMO-1618 [(5-hydroxycarvacryl)trimethylammonium chloride 1-piperidine-carboxylate]) treatment on the development of antheridia of 'Chara vulgaris L.' were compared. After 24 h both factors inhibited endo-replication in manubria. In the youngest antheridia the inhibition of ³H-thymidine incorporation following plasmolysis was irreversible while the same effect caused by AMO-1618 disappeared after 3 days. Four-five days after plasmolysis or five days after AMO-1618 treatment anheridia which were at the stage of spermiogenesis had a lower of DNA in manubria and revealed decreased productivity due to the smaller number of mitotic divisions in antheridial filaments. On the basis of the previous and present data a hypothesis was out forward that in both experiments premature spermiogenesis was caused by a rapid decrease in gibberellin level in the antheridia. (author). 43 refs, 5 figs

[en] Normal hematopoietic progenitors and acute myelogenous leukemia cells show a differential requirement for the encoded product of c-myb proto-oncogene for proliferation. To determine whether c-myb is also differentially required for the proliferation of hematopoietic progenitors of chronic myelogenous leukemia (CML), mononuclear cells derived from both chronic phase and blast crisis were exposed to c-myb antisense oligodeoxynucleotides and assayed for colony-forming ability. Exposure of CML-BC cells from 12 patients to c-myb antisense oligodeoxynucleotides resulted in significant inhibition of leukemia colony formation and was accompanied by down-regulation of c-myb expression. Colonies derived from CML chronic phase progenitors were virtually unaffected in 10 cases, but down-regulation of c-myb expression was not detected. However, in studies conducted with CD34+ leukemia cells, a subset highly enriched for hematopoietic progenitors, colony formation was inhibited at both disease stages, whereas CFU-GM colony formation derived from normal CD34+ cells was not affected by exposure to c-myb antisense oligodeoxynucleotides. These data suggest that CML chronic phase and blast crisis progenitors are both sensitive to the inhibitory effects of c-myb antisense oligomers, and that the lack of inhibition in partially purified CML-chronic phase progenitors is probably due to inefficient penetration of oligodeoxynucleotides into the clonogenic cells. The preferential effect of c-myb antisense oligodeoxynucleotides on colonies arising from the compartment that includes CML-CD34+ progenitors likely reflects the expansion of a cell population with high proliferative potential and elevated c-myb mRNA levels. (author). 26 refs, 4 figs, 3 tabs

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[en] Autoradiographic studies with ³H-fucose have shown that this precursor of polysaccharide compounds is incorporated into manubria and antheridial mucilage of Chara vulgaris both in the light and in the darkness. The dynamic of this process is lower in total darkness. The decrease in overall labelling of antheridium (manubria an mucilage) reflects secondary metabolic changes both in proliferative phase and in spermiogenesis. The pulse (2 and 5 min) incubations with the isotope confirm the intensive mucilage translocation which at later developmental stages is more dynamic than at earlier ones. It can explain previously observed decrease in manubria radioactivity at later stages after long (40 min) incubation, because PAS-positive polysaccharide synthesis is simultaneous with their fast translocation to the antheridial space. The present and previous autoradiographic and cytophotometric data taken altogether confirm the assumption about a nutritive role of mucilage filling Chara antheridium during the process of spermatogenesis. (author). 19 refs, 7 figs

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