High light acclimation of Chromera velia points to photoprotective NPQ

Photosynthesis Research - It has previously been shown that the long-term treatment of Arabidopsis thaliana with the chloroplast inhibitor lincomycin leads to photosynthetic membranes enriched in...     

The Xerobranching Response Represses Lateral Root Formation When Roots Are Not in Contact with Water

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Improvement ofArabidopsis thaliana seed transformation efficiency

Agrobacterium tumefaciens induced transgenosis by treatment of germinatingArabidopsis thaliana seed embryos has been achieved with differentAgrobacterium strains including the strain LBA4404, which was ineffective in seed transformation experiments of the other authors. The frequency of transgenosis was increased several times by application of acetosyringone to the growingA. tumefaciens suspension cultures. The DNA demethylating agent 5-azacytidine partly restored the distorted Mendelian segregation ratios in the offspring of transgenic plants.     

Comparison of hairy root and crown gall tumors ofArabidopsis thaliana

The phenotype appearance ofArabidopsis thaliana hairy roots and crown galls their teratomas and regenerated plants were compared. Several differences were found, which correlate with T-DNA differences between Ti and Ri plasmids. Presented at the International Symposium “Plant Growth Regulators” held on June 18–22, 1984 at Liblice, Czechoslovakia.     

Chromosomal characteristics of barley root meristems differentiated from calli

Callogenesis was induced in mature embryos. The efficiency of induction and the growth of calli were dependent on 2,4-D concentration. No regeneration of buds or shoots was observed in 720 calli studied, but most calli showed intensive root proliferation on the regeneration medium. Most of the root meristem cells maintained diploid chromosome number. Only a low proportion (about 3.5%) of tetraploid cells was found. No other chromosomal changes were observed. Chromosomal variability does not contribute to the inability of calli derived from mature barley embryos to form buds and shoots.     

Method of calculating the strength of genetic linkage in gene interaction

Poposaná metoda je modifikací (Immer 1930) sou?inové formule. Byl uveden p?íklad výpo?tu p?i pou?ití této metody.     

The use of styrene-maleic acid copolymer (SMA) for studies on T cell membrane rafts

An emerging alternative to the use of detergents in biochemical studies on membrane proteins is apparently the use styrene-maleic acid (SMA) amphipathic copolymers. These cut the membrane into nanodiscs (SMA-lipid particles, SMALPs), which contain membrane proteins possibly surrounded by their native lipid environment. We examined this approach for studies on several types of T cell membrane proteins, previously defined as raft or non-raft associated, to see whether the properties of the raft derived SMALPs differ from non-raft SMALPs. Our results indicate that two types of raft proteins, GPI-anchored proteins and two Src family kinases, are markedly present in membrane fragments much larger (>250?nm) than those containing non-raft proteins (<20?nm). Lipid probes sensitive to membrane fluidity (membrane order) indicate that the lipid environment in the large SMALPs is less fluid (more ordered) than in the small ones which may indicate the presence of a more ordered lipid L_o phase which is characteristic of membrane rafts. Also the lipid composition of the small vs. large SMALPs is markedly different – the large ones are enriched in cholesterol and lipids containing saturated fatty acids. In addition, we confirm that T cell membrane proteins present in SMALPs can be readily immunoisolated. Our results support the use of SMA as a potentially better (less artifact prone) alternative to detergents for studies on membrane proteins and their complexes, including membrane rafts.