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At least 253 records · Page 14Linked to original sources
PubMed1986

The possible involvement of root-cap mucilage in gravitropism and calcium movement across root tips of Allium cepa L.

Roots of Allium cepa L. grown in aerated water elongate rapidly, but are not graviresponsive. These roots (1) possess extensive columella tissues comprised of cells containing numerous sedimented amyloplasts, (2) lack mucilage on their tips, and (3) are characterized by a weakly polar movement of calcium (Ca) across their tips. Placing roots in humid air correlates positively with the (1) onset of gravicurvature, (2) appearance of mucilage on tips of the roots, and (3) onset of the ability to transport Ca polarly to the lower side of the root tip. Gravicurvature of roots previously submerged in aerated water is more rapid when roots are oriented vertically for 1-2 h in humid air prior to being oriented horizontally. The more rapid gravicurvature of these roots correlates positively with the accumulation of mucilage at the tips of roots during the time the roots are oriented vertically. Therefore, the onset of gravicurvature and the ability of roots to transport Ca to the lower sides of their tips correlate positively with the presence of mucilage at their tips. These results suggest that mucilage may be important for the transport of Ca across root caps.

Allium↗
PubMed1999

Welsh onion (Allium fistulosum L.) extracts alter vascular responses in rat aortae.

Welsh onion, a member of the genus Allium, has been consumed for prevention of cardiovascular disorders. However, its underlying mechanisms are still unclear. We investigated whether Welsh onion extracts (green or white portion, raw or boiled) can alter vascular responses in vitro in the thoracic aortae of Sprague-Dawley rats. The possible roles of endothelium-derived factors in the Welsh onion extract-induced vascular responses were examined by applying various inhibitors, such as Nomega-nitro-L-arginine (10(-4) M), tetraethylammonium (10(-3) M), and SQ29548 (10(-5) M). Our results showed that Welsh onion extracts caused vasodilation on precontracted vessel rings. These effects were most pronounced in vessel rings treated with raw green-leaf extract (RG). Low doses of RG induced vasorelaxation, which was mediated by endothelium-derived nitric oxide. High doses of RG induced endothelium-independent vasorelaxation. On the other hand, the boiled Welsh onion extract also stimulated the release of an endothelium-derived contracting factor, which might be thromboxane A2. We conclude that Welsh onion extract can modulate vascular tone in both endothelium-dependent and endothelium-independent manners.

Allium↗
PubMed2001

The importance of sexual and asexual reproduction in the recent evolution of Allium vineale.

In the weedy plant species Allium vineale (wild garlic), individuals may simultaneously produce sexually and asexually derived offspring, by seed and bulbils, respectively. In this study, genetic and genotypic diversity was determined in samples from 14 European A. vineale populations using nuclear (RAPD) and cytoplasmic (PCR-RFLP of cpDNA) markers to investigate the importance of the different reproductive modes. In the whole sample, 77 nuclear multilocus genotypes and four chloroplast haplotypes (chlorotypes) were found. Populations exhibited a high degree of subdivision for nuclear and cytoplasmic markers as estimated from hierarchical F-statistics; at the same time, identical chlorotypes could be found in populations separated by large distances. Genotypic diversity was significantly lower than expected under free recombination in almost all populations, indicating that recruitment into populations is mostly by asexually produced offspring. Nevertheless, within each chlorotype, the distribution of markers from pairs of nuclear loci was incompatible with a purely clonal structure, suggesting that many multilocus genotypes have originated by sexual recombination rather than by mutation within asexual lineages. It is argued that the weedy habit of A. vineale is likely to have favored bulbil reproduction, whereas sexually generated genotypes may have facilitated local adaptation during the species' expansion across Europe.

Allium↗
PubMed2001

Searching for telomeric sequences in two Allium species.

Some Alliaceae species have no tandemly repeated TTTAGGG sequences. Instead, at the very end of their chromosomes, there are highly repetitive satellite and (or) rDNA sequences. These sequences apparently replace the canonical plant telomeric sequences in these species. A method of preparing two-dimensional surface spreads of plant synaptonemal complexes (SCs), combined with fluorescent in situ hybridization, has revealed that telomeric chromatin is tightly condensed at the ends of SCs in plants and animals. Using this method, we have tested the organization and location of those sequences postulated to cap the chromosomes in two species of the genus Allium: A. cepa and A. altaicum. We have also extended this study to other putative telomere candidates, such as LTR (long terminal repeat) and non-LTR retrotransposons. None of the DNA sequences analyzed showed the characteristic telomeric organization at pachytene.

Allium↗
PubMed1986

Cell proliferation in Allium cepa L. meristems under 8-hydroxyquinoline, a chelating agent that affects DNA and RNA polymerases.

8-Hydroxyquinoline (HQ) chelates Mg2+ and Mn2+ and, secondarily, affects the activities of DNA and RNA polymerases. The in vivo effect of HQ has been estimated in Allium cepa L. meristems growing under new growth kinetics in the presence of this agent. HQ (at both 5 X 10(-5) M and 10(-4) M) depressed incorporation of [3H]uridine much more effectively than that of [3H]-thymidine. Cycle kinetics in meristems behaved as if they were independent of the rates of synthesis or accumulation of RNA since, under HQ, cycle time was only moderately modified and the new cycle kinetics achieved could be explained by the new rates of [3H]thymidine incorporation. Lengthened S periods were partially compensated for by shortened G2 phases, suggesting that, in these cells, both the growth cycle and its coupling with the DNA-division cycle were not disturbed by a decreased amount of RNA. Finally, the nucleolar cycle during mitosis, but not the interphase nucleolus, was modified under the new rates of RNA synthesis.

Allium↗
PubMed1987

Synaptonemal complex spreading in Allium ursinum: pericentric asynapsis and axial thickenings.

In Allium ursinum meiotic pairing of homologues is always incomplete; a proximal region on each bivalent remains regularly unsynapsed even in late pachytene. The spatial correlation of the unsynapsed region with the kinetochore suggests that the kinetochore itself exerts an inhibitory effect on synapsis in its vicinity. This can be interpreted as the cytological basis of the 'centromere effect' on recombination in this species. Moreover, the high incidence of a pericentric inversion loop in a heterozygous chromosome pair shows that proximal pairing initiation is possible and that its failure cannot be responsible for pericentric asynapsis. The formation of the inversion loop is complicated by the need for two independent pairing initiation sites because synapsis cannot proceed across the pericentric region. It is proposed that the meiotic bouquet polarization helps in establishing the presynaptic alignment of the homologous sites within the inverted regions and hence to achieve a high rate of inversion loop formation. Thickenings of the axial/lateral elements are not distributed equally along the synaptonemal complex. They are underrepresented in unpaired axes but strikingly abundant at the borders with synapsed regions, suggesting their origin in the pairing forks during the process of synapsis. They are virtually always present at nucleolus-organizing regions and often they appear at corresponding sites on opposite lateral elements. Besides the thickenings several other kinds of axial deformities are present in unpaired axes.

Allium↗
PubMed2000

Saponins isolated from Allium chinense G. Don and antitumor-promoting activities of isoliquiritigenin and laxogenin from the same drug.

Investigation of the Chinese crude drug "Xiebai," the bulbs of Allium chinense G. Don (Liliaceae), led to the isolation of 2 saponins, xiebai-saponin I (laxogenin 3-O-beta-xylopyranosyl (1-->4)-[alpha-arabinopyranosyl (1-->6)-beta-glucopyranoside) (1) and laxogenin 3-O-alpha-arabinopyranosyl (1-->6)-beta-glucopyranoside (2), and the aglycone, laxogenin (3), together with 2 chalcones, isoliquiritigenin (4) and isoliquiritigenin-4-O-glucoside (5), and beta-sitosterol glucoside (6). Compounds 1-5 were tested in vitro for their inhibitory effect on the 12-O-tetradecanoylphorbol-13-acetate (TPA)-stimulated 32Pi-incorporation into phospholipids of HeLa cells. In addition to this, laxogenin (3) was proven to have an antitumor-promoting activity in a two-stage lung carcinogenesis experiment.

Allium↗
PubMed1994

Further studies on new furostanol saponins from the bulbs of Allium macrostemon.

Further studies by means of preparative HPLC led to the isolation of two new furostanol saponins, macrostemonoside J (1) and L (3), along with an artifact, macrostemonoside K (2) from the bulbs of Allium macrostemon. On the basis of chemical evidence and spectral analysis (1H-, 13C-NMR and FAB-MS), the structure of 1 was elucidated to be 26-O-beta-D-glucopyranosyl 2 beta,3 beta,22,26-tetrahydroxy-25(R)-5 beta-furostan 3-O-beta-D-glucopyranosyl (1-->2)-beta-D-galactopyranoside. 3 was deduced to be 26-O-beta-D-glucopyranosyl 2 beta,3 beta,26-trihydroxy-25(R)-5 beta-furostan- 20(22)-ene 3-O-beta-D-glucopyranosyl (1-->2)-beta-D-galactopyranoside.

Allium↗
PubMed1994

New steroidal saponins from the bulbs of Allium giganteum exhibiting potent inhibition of cAMP phosphodiesterase activity.

A new spirostanol saponin and two new furostanol saponins were isolated from the fresh bulbs of Allium giganteum together with several known saponins. The structures of the new compounds were determined on the basis of spectroscopic data, the products formed on hydrolysis and by comparing their properties with those of known compounds. The isolated saponins and their derivatives were evaluated for inhibitory activity by examining their action on cAMP phosphodiesterase as a primary screening test to identify new medicinal agents.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1999

Steroidal saponins from the bulbs of Allium karataviense.

Chemical examination of the bulbs of Allium karataviense led to the isolation of five new spirostanol saponins (7-11) and a new furostanol saponin (12), together with a known steroidal sapogenin (1) and five known saponins (2-6). The structures of the new saponins were determined by detailed analysis of their spectral data, including two-dimensional NMR spectroscopy. The steroidal saponins produced by A. karataviense, except for 5 and 6, were found to be based upon (25R)-5 alpha-spirostane-2 alpha,3 beta,5,6 beta-tetrol (alliogenin) and contain a beta-D-glucopyranosyl moiety with the formation of an O-glycoside linkage to C-2 of the polyhydroxylated steroidal skeleton as the common structural feature. The isolated compounds were evaluated for cytostatic activity against human promyelocytic leukemia HL-60 cells.

Allium↗
PubMed2000

Steroidal oligoglycosides from the seeds of Allium tuberosum.

Three new spirostanol steroidal oligoglycosides, together with a known oligoglycoside, were obtained from the seeds of Allium tuberosum after enzymatic hydrolysis of furostanol saponin fraction by beta-glucosidase. On the basis of spectroscopic analysis, the structure of new spirostanol oligoglycosides were elucidated as (25S)-spirost-5-ene-2alpha,3beta-diol 3-O-alpha-L-rhamnopyranosyl-(1-->4)-[alpha-L-rhamnopyranosyl-(1-->2)]-be ta-D-glucopyranoside, (25S)-spirostane-3beta,5beta,6alpha-triol 3-O-alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranoside, and (25S)-5beta-spirostane-3beta,6alpha-diol 3-O-alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranoside.

Allium↗
PubMed2004

Pregnane- and furostane-type oligoglycosides from the seeds of Allium tuberosum.

Two furostane-type steroidal oligoglycosides (1, 2), together with a new pregnane-type oligoglycoside (3), were obtained from the seeds of Allium tuberosum ROTTLER. On the basis of spectroscopic analysis, the structures of three new oligoglycosides (1-3) were elucidated as 26-O-beta-D-glucopyranosyl-(25R)-3beta,22xi,26-trihydroxyl-5alpha-furostane 3-O-beta-chacotrioside, 26-O-beta-D-glucopyranosyl-(25S)-3beta,5beta,6alpha,22xi,26-pentahydroxyl-5beta-furostane 3-O-alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranoside, and 3-O-alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl 3beta,5beta,6alpha,16beta-tetrahydroxypregnane 16-(5-O-beta-D-glucopyranoyl-4(S)-methyl-5-hydroxypentanoic acid) ester, respectively.

Allium↗
PubMed2004

Production and characterization of alien chromosome additions in shallot (Allium cepa L. Aggregatum group) carrying extra chromosome(s) of Japanese bunching onion (A. fistulosum L.).

First and second backcrosses of amphidiploid hybrids (2n = 4x = 32, genomes AAFF) between shallot (Allium cepa Aggregatum group) and A. fistulosum were conducted to produce A. cepa - A. fistulosum alien addition lines. When shallot (A. cepa Aggregatum group) was used as a pollinator, the amphidiploids and allotriploids set germinable BC(1) and BC(2) seeds, respectively. The 237 BC(1) plants mainly consisted of 170 allotriploids (2n = 3x = 24, AAF) and 42 hypo-allotriploids possessing 23 chromosomes, i.e., single-alien deletions (2n = 3x-1 = 23, AAF-nF). The single-alien deletions in the BC(1) progeny showed dwarfing characteristics and were discriminated from the allotriploids (2n = 24) and hyper-allotriploids (2n = 25) by means of flow cytometric analysis. The chromosome numbers of 46 BC(2) seedlings varied from 16 to 24. Eight monosomic additions (2n = 2x+1 = 17, AA+nF) and 20 single-alien deletions were found in these BC(2) seedlings. Consequently, six kinds of A. cepa - A. fistulosum alien chromosome additions possessing different chromosome numbers (2n = 17, 18, 20, 21, 22, 23) were recognized in the BC(1) and BC(2) populations. A total of 79 aneuploids, including 62 single-alien deletions, were analyzed by a chromosome 6F-specific isozyme marker (Got-2) in order to recognize its existence in their chromosome complements. This analysis revealed that two out of 62 single-alien deletions did not possess 6F. One (AAF-6F) out of the possible eight single-alien deletions could be identified at first. The present study is a first step toward the development of a useful tool, such as a complete set of eight different single-alien deletions, for the rapid chromosomal assignment of genes and genetic markers in A. fistulosum.

Allium↗
PubMed2004

Effect of single alien chromosome from shallot (Allium cepa L. Aggregatum group) on carbohydrate production in leaf blade of bunching onion (A. fistulosum L.).

We used a complete set of Allium fistulosum - shallot (A. cepa Aggregatum group) monosomic addition lines (FF+1A - FF+8A) to identify shallot chromosomes affecting the production of sugars. In the alien addition lines grown over two years in an experimental field at Yamaguchi University (34 degrees N, 131 degrees E), shallot chromosomes 2A and 8A altered sugar contents in leaf-bunching onion (A. fistulosum). Except for FF+2A, every monosomic addition accumulated non-reducing sugars in winter leaf blades. FF+8A caused an increase in the amounts of non-reducing sugars in the winter. FF+2A hardly produced non-reducing sugar throughout the two-year study. These results indicated that genes related to non-reducing sugar metabolism are located on the 2A and 8A chromosomes. The results of regression analyses using 2002 data on A. fistulosum and the monosomic addition set revealed a correlation (r = 0.63 +/- 0.07; mean +/- SE., n = 9) between reducing sugar and monosaccharide (Glc+Fru) contents but no correlation between non-reducing sugar and sucrose contents. This result indicates the existence of other polysaccharides (e.g., scorodose) as non-reducing sugars in the leaf blade.

Allium↗
PubMed1994

Malonylated anthocyanins from bulbs of red onion, Allium cepa L.

Four cyanidin-based anthocyanins (1-4) were isolated from the red onion, Allium cepa L. Pigments 1 and 3 were identified as cyanidin 3-glucoside (Cy 3-Glc) and 3-malonylglucoside (Cy 3-MaGlc), respectively, by cochromatography with standard pigments. Anthocyanins 2 and 4 were respectively determined as cyanidin 3-laminaribioside (Cy 3-Lam) and 3-malonyllaminaribioside (Cy 3-MaLam), a new anthocyanin, mainly by NMR techniques. Malonylated anthocyanins 3 and 4 were found for the first time in red onions.

Allium↗
PubMed2002

Comparison of C-S lyase in Lentinus edodes and Allium sativum.

The characteristics of C-S lyase in Lentinus edodes (shiitake) were compared with those in Allium sativum (garlic). C-S lyase mRNA from shiitake was hybridized with the garlic C-S lyase cDNA fragment, being almost the same length as that from garlic. The isoelectric point of the C-S lyase from shiitake was between pH 4 and 5, while that from garlic was over a wider range between pH 4 and 8. Different from the C-S lyase from garlic, that from shiitake was not a glycoprotein without being stained by PAS, and was not bound to the anti-garlic C-S lyase antibody. Similar to garlic C-S lyase, shiitake C-S lyase comprised a homodimer, and its molecular mass was 84 kDa. However, the N-terminal amino acid sequences of each subunit of shiitake C-S lyase were totally different from those of garlic C-S lyase.

Allium↗
PubMed1989

Effect of oral ingestion of different fractions of Allium cepa on the blood and erythrocyte membrane lipids and certain membrane-bound enzymes in rats.

The effect of oral ingestion of different fractions of onion (Allium cepa)--extract, residue, and whole--at a dose level equivalent to intake of 50 g of onion per day for a 70-kg man, for 30 days, to male adult, normal, albino rats was studied on blood and erythrocyte membrane lipids and certain membrane-bound enzymes. Onion extract and residue showed hypercholesterolemic effect, while whole onion showed hypocholesterolemic effect in blood. In erythrocyte membranes, all the fractions had hypocholesterolemic and hypolipidemic effect, which was accompanied by changes in the erythrocyte membrane enzymes studied, i.e., alkaline and acid phosphatase, 5'-nucleotidase, total and Mg2+ ATPase. The above study indicated that it is safer to take whole onion rather than onion residue or extract, because whole onion could lower the blood cholesterol level even in normal condition and has a less pronounced effect on the micro-environment of the cells.

Acid Phosphatase↗
PubMed2000

[ScII-like protein is localized in the nuclei, chromosomes and chromosome scaffolds of Allium cepa].

The nuclei were isolated from the root meristematic cells of Allium cepa and the nuclear matrices were prepared. A 135 kD polypeptide, which is equivalent to Sc II in molecular weight, was revealed in the nuclei by SDS-PAGE and was then demonstrated to be an Sc II-like protein by Western blot with an anti-chicken Sc II antiserum. Neither the 135 kD polypeptide nor the positive labelling of the anti-Sc II antiserum was found in the nuclear matrices. The immuno-fluorescence tests showed that the nuclei labelled with the anti-Sc II antiserum emanated strong, specific fluorescence, while the fluorescence of the nuclear matrices was too weak to be detected. The results of immunoelectron microscopy indicated that a large number of the gold particles were concentrated in the condensed chromatin of the nuclei, but very few gold particles were distributed in cytoplasm and nucleoplasm. These results strongly suggested that an Sc II like protein is a component of the nuclei of A. cepa and is mainly located in the condensed chromatin regions, but the nuclear matrices contain no or very little amount of that protein. By means of immunofluorescence and immunoelectron microscopy, the chromosomes and chromosomal scaffolds of A. cepa labelled with the anti-chicken Sc II antiserum were observed to send off specific fluorescence and have many gold particles representing the presence of the Sc II-like protein distributed among them. The significance of the Sc II-like protein as a novel component in the nuclei, chromosomes and chromosome scaffolds of higher plants is discussed.

Allium↗