Ruhe bitte! Polysperminimidazol‐4,5‐imin (blaue Linien) wurde durch Kondensation von Spermin mit Bisformaldehydimidazol über eine pH‐empfindliche Bindung erhalten und verwendet, um siRNAs zu ...Nanopartikeln zu kondensieren (siehe Schema) und ihren Transport in Zellen sowie die Freisetzung aus Endosomen zu untersuchen. Nach Zell‐ und In‐vivo‐Studien können mit diesem siRNA‐Träger Zielgene mit vernachlässigbarer Cytotoxizität effizient ausgeschaltet werden.
In order to explore the property and mechanism of DNA condensation, the authors studies the effect of different concentrations of spermine(SPM), spermidine (SPD) and hexamminecobalt(III) chloride on ...the ultraviolet (UV) absorption value of calf thymus DNA by UV spectrophotometer from the macro. The results showed that SPD and SPM interaction with the DNA had the similar characteristics in UV spectrum. The UV absorption value of calf thymus DNA at 260 nm appeared increased-decreased-increased with the increasing the concentration of SPD and SPM. The value of hexamminecobalt(III) chloride system showed decreased and then increased, suggesting that SPM, SPD and hexamminecobalt(III) chloride could make DNA condense, but in different ways. Relatively, hexamminecobalt(III) chloride was more sensitive than SPD and SPM. The result of UV spectral analysis coincided with recent single-molecule experimental results.
The aim of this study was to assess the effects of spermidine (Spd) on ameliorating adverse effects of salinity
in Troyer citrange seedlings. For this purpose, 6-month-old, uniform-sized seedlings of ...Troyer citrange were transplanted
to plastic containers containing Hoagland nutrient solution. Addition of 75mMNaCl into the nutrient solution reduced
the plant growth, leaf chlorophyll content, chlorophyll Zuorescence yield (Fv/Fm), net photosynthetic rate, respiration
rate, and total Spd, N, and $Ca^ {2+}$ + $Mg^ {2+}$ contents of the leaves. It increased the leaf proline, total putrescine (Put), total
spermine (Spm), $Na^ +$, and Cl- contents of the leaves. Addition of Spd (0.1 or 0.5 mM) to the saline nutrient solution and
its weekly sprays (1 or 5 mM) on NaCl-stressed plants improved leaf number, chlorophyll content, Fv/Fm, net
photosynthetic rate, and N content; increased total Spd and Spm contents; and reduced $Na^ +$ contents of the plants. Leaf
$Ca^ {2+}$ + $Mg^ {2+}$contents were slightly improved only when Spd (0.5 mM) was added to the saline nutrient solution. Leaf P
and K+ contents were not significantly affected by the salinity or Spd treatments. Among the polyamines, Put content was
least affected, while there was a sharp increase in Spm content due to the salinity and Spd treatments. These results
suggest involvement of Spm in the salinity tolerance of citrus rootstock Troyer citrange.
Buds from newly developed shoots obtained from forced outgrowth of mature field-grown hybrid hazelnut trees (Corylus avellana L.) were cultured in vitro on Murashige and Skoog MS (1962) medium and a ...modified Driver and Kuniyuki DKW (1984) medium containing 6.7 µM, 11.1 µM or 15.5 µM of N-6 benzyladenine (BA) supplemented with or without a combination of polyamines (0.2 mM of putrescine + 0.2 mM of spermidine + 0.05 mM of spermine). The effects of culture medium and BA were found to be insignificant on explant response. Polyamines were found to have a strong effect on both shoot elongation and on number of buds per shoot. Polyamines stimulated mean shoot elongation by 83% and increased the mean number of buds per shoot by 41% compared to when they were not used. In the presence of polyamines, shoot elongation continued up to 4.0 cm while in the absence of polyamines shoot elongation only reached 2.0 cm. Results indicate that polyamines in the culture medium could ease the establishment of cultures and enhance the morphogenic capacity of mature explants.
In
Solanum Melongena L. Cv. Pusa Purple Long, Significant Differences Were Observed For Embryogenic Potential Within A Single Explant (Hypocotyl System). Terminal Hypocotyl Segments (Apical and ...Basal) Yielded A Higher Number Of Somatic Embryos Than The Medial (Sub-Apical and Sub-Basal) Segments. High Levels Of Conjugated Spermidine Along With High Levels Of Total Polyamines (Primarily Free Fraction) Could Be Correlated With The Formation Of Somatic Embryos In Terminal Segments. Temporal Changes In Endogenous Levels Of Free, Conjugated and Bound Putrescine, Spermidine and Spermine Were Analyzed At Critical Stages Of Somatic Embryogenesis From Four Different Hypocotyl Segments. Within 3 Days Of Culture, There Was A Sharp Decline In Free (and Total) Putrescine and An Increase In Conjugated Spermidine Levels. All Hypocotyl Segments Attained Similar Levels Of Free Spermidine, Irrespective Of Their Subsequent Embryogenic Response. As The Tissues Become Committed For Embryogenesis, Free, Conjugated and Total Putrescine and Spermidine Reach Uniformly Minimal Levels For All Segments. Just Before The Onset Of Embryogenesis, There Was A Dramatic Increase In All Fractions Of Putrescine, and In Free and Conjugated (Along With Total) Spermidine Levels. Intermediate Levels Of Conjugated and Total Putrescine and Spermidine Were Reached In Tissues With Good Embryogenic Potential: tissues with poor embryogenic potential attained lower or higher levels. After the embryos were formed, their levels fell sharply, and continued to decline. Free putrescine, however, reached another peak when embryos had fully matured. The changes in bound putrescine and spermidine, and in spermine (all forms) could not be correlated with somatic embryogenesis.
Bu çalışmada, spermidin (Spd), spermin (Spm) ve sikloheksilamin'nin (CHA), diploid (Triticum monococcum L.), tetraploid (T. durum Desf.) ve heksaploid (T. aestivum L.) buğdaylarda tohum çimlenmesi, ...kök uzaması, mitotik indeks ve kromozomların davranışına etkileri incelendi. Poliaminler üç türde de tohum çimlenmesini inhibe etti. CHA diploidlerde ve tetraploidlerde tohum çimlenmesini inhibe ederken, heksaploidlerde çimlenmeyi teşvik etti.
Spd, Spm ve CHA üç türün kök uzamasını inhibe etti. Spd ve Spm diploidlerde ve tetraploidlerde mitotik indekste inhibisyona neden olurken, heksaploidlerde Spd artışa, Spm ise düşüşe neden oldu. CHA üç türün kök uçlarında da mitoz bölünme frekansını düşürdü. Her üç türün kontrol grubunda da mitotik anormallikler gözlendi. Bu anormallikler bozuk metafaz tablası, anafazda kromozom köprüleri, eşit olmayan dağılım, geç kalan kromozomlar, çok kutuplu iğ ipliği şeklinde özetlenebilir. Spd, Spm ve CHA üç türde de anormallik yüzdesini etkiledi. Sonuçlar, kök uzamasındaki inhibisyonun bu maddelerin mitotik indeksi düşürmelerinden kaynaklandığını gösterdi.
The effects of spermidine (Spd), spermine (Spm) and cyclohexylamine (CHA) on seed germination, root elongation, mitotic index and chromosomal behavior were studied in diploid (Triticum monococcum L.), tetraploid (T. durum Desf.) and hexaploid (T. aestivum L.) wheats. The polyamines (PA) inhibited seed the germination in three species. CHA inhibited seed germination in diploid and tetraploid species, but it showed a stimulation in hexaploid seeds. Spd, Spm and CHA reduced root elongation in three species. Spd and Spm decreased mitotic index in diploids and tetraploids. In hexaploids, Spd slightly increased the division frequency whereas Spm decreased it. The root tips of the three species treated with CflA showed maximum inhibition in mitotic index. Some mitotic abnormalities like unoriented metaphase, anaphase bridges, unequal distribution, laggards, multipolar spindle fibers were observed in the control groups of diploid, tetraploid and hexaploid. Spd, Spm and CHA affected the percentages of aberrations. Our results suggested that the reason of the inhibition in root elongation was due to the reduction in the mitotic index.
Effect of intraperitoneal administration of spermin on oxidative phosphorylation and calcium capacity of isolated liver mitochondria was studied in normo- and hypothermic rats. Hypothermia stimulates ...mitochondrial respiration without decreasing the contingency and increases calcium capacity. Spermin suppresses mitochondrial respiration, the effect being stronger in hypothermia. In high doses spermin prevents stimulating effect of hypothermia on respiration and reduces the increase in calcium capacity.PUBLICATION ABSTRACT
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