Synthesis and Antiproliferative Activity of Some New Coumarin Derivatives Derived from 8-Hydroxycoumarin

Russian Journal of Bioorganic Chemistry - A new series of coumarin-derived molecules have been synthesized and evaluated for their anticancer activity against human hepatocellular liver carcinoma...     

Structural changes during the first divisions of embryos resulting from anther and free microspore culture inBrassica napus

Summary Ultrastructural and cytochemical features of embryo development during anther and free microspore culture inBrassica napus have been followed from the late uninucleate microspore stage through the first embryonic division. On transfer to culture, the microspore cytoplasm possesses a large vacuole, often containing electron opaque aggregates, and a peripheral nucleus. Mitochondria, endoplasmic reticulum and starch-free plastids are distributed throughout the cytoplasm. The conditions of culture induce a number of major changes in the cytoplasmic organisation of the microspore. First, the central vacuole becomes fragmented allowing the nucleus to assume a central position within the cell. Secondly, starch synthesis commences in the plastids which, in turn, are seen to occupy a domain investing the nucleus. Thirdly, the cell develops a thick fibrillar wall, situated immediately adjacent to the intine of the immature pollen wall. Finally, the microspores develop large cytoplasmic aggregates of globular material. The nature of this substance remains unknown, but it remains present until the young embryos have reached the 30 cell stage. The first division of cultured microspores destined to become embryos is generally symmetrical, in contrast to the asymmetric division seen in normal development in vivo. Consideration is given to the differences observed between embryos developing from anthers and free microspores in culture.     

Nematicidal and allelopathic potential of Argemone mexicana,a tropical weed

Argemone mexicana L. (Papaveraceae), a tropical annual weed, is phytotoxic to many crop species. This study was designed to examine the allelochemical and nematicidal potential of A. mexicana and to better understand the role of this weed in the ecosystem. A methanol-soluble extract of the leaf material caused greater juvenile mortality of Meloidogyne javanica than did ethyl acetate or hexane extracts indicating the polar nature of the toxins. Decomposing tissues of A. mexicana in soil at 50 g kg^–1 were highly deleterious causing 80% mortality of tomato plants. At 10 g kg^–1 plant growth was enhanced, while at 30 g kg^–1 plant growth was substantially retarded. M. javanica population densities in the rhizosphere and in roots, and gall formation were significantly suppressed when 10, 30 or 50 g kg^–1 A. mexicana was allowed to decompose in the soil. To establish whether decomposition was necessary to produce phytotoxic symptoms, or whether the shoot extract alone could interfere with plant growth, an aqueous shoot extract was applied to soil. Whereas a 50% extract promoted plant growth, a 100% (100 g/500 mL distilled water) concentration significantly reduced plant height, and fresh weights of shoot and root. In general, decomposing plant material caused greater phytotoxicity compared to the aqueous extract. Addition of N as NH₄NO₃ partially alleviated the phytotoxic action of A. mexicana,and also reduced severity of root-knot disease. Adding Pseudomonas aeruginosa to soil amended with A. mexicana resulted in decreased density of M. javanicain the rhizosphere and in tomato roots, suppressed galling rates and enhanced plant growth.     

Design,Synthesis, and Cytotoxic Screening of New Quinoline Derivatives over MCF-7 Breast Cancer Cell Line

Russian Journal of Bioorganic Chemistry - VEGFR-2 inhibition represents an attractive strategy for anticancer drug design. A new series of quinoline derivatives were synthesized and structurally...