[Effects of NaCl stress on polyamine contents in grafted cucumber leaves].

With a Japanese salt-tolerant pumpkin cultivar 'King Shintosa' (Cucurbita maxima x C. moschata) as rootstock and a cucumber (Cucumis sativus) cultivar 'Xintaimici' as cion, this paper studied the temporal dynamics of different form polyamines contents in the leaves of grafted and own-rooted cucumber plants under 100 mmol x L(-1) NaCl stress. The results showed that the free putrescence (Put) content of graftedplant leaves (G2) was significantly higher than that of own-rooted plant leaves (O2), except on the second day of NaCl stress. During the whole period of NaCl stress, the free spermidine (Spd) and spermine (Spm) contents of G2 were significantly higher than those of O2, and the total free polyamine content of G2 peaked on the fourth day of stress. The free Put/PAs value of G2 was significantly lower than that of O2 except on the fourth day of stress, but (Spd + Spm)/Put value was significantly higher than that of O2 during the whole period of stress. In the test period, the contents of conjugated and bound Put, Spd, Spm of G2 were significantly higher than those of O2. The total conjugated and bound polyamine contents of G2 peaked on the sixth day of stress. Both conjugated Put/PAs and conjugated (Spd + Spm)/Put values had a similar changing trend to free polyamine. The bound Put/PAs value of G2 was significantly lower than that of O2 except on the sixth day of stress, while the bound (Spd + Spm)/Put value was significantly higher than that of O2 during the whole period of stress. All of these demonstrated that grafted cucumber plant possessed a stronger salt tolerance.

[Effects of NaCl stress on the growth, antioxidant enzyme activities and reactive oxygen metabolism of grafted eggplant].

By the method of hydroponics and with the salt-tolerant eggplant cultivar 'Torvum Vigor' (Solanum torvum) from Japan as rootstock and the cultivar 'Suqiqie' (Solanum melongena L. ) as scion, this paper studied the differences between grafted and own-root seedlings in their photosynthetic characteristics, antioxidant enzyme activities, and reactive oxygen metabolism under 80 mmol x L(-1) NaCl stress. The results showed that under NaCl stress, the dry mass, chlorophyll content and photosynthetic rate of grafted seedlings were 67.8%, 8. 8% and 31.1% higher than those of own-root seedlings, respectively, and the antioxidant enzyme activities were significantly higher while the O2* producing rate and the hydrogen peroxide (H2O2) and malondiadehyde (MDA) contents were significantly lower in grafted seedlings leaves than in own-root seedlings. For both grafted and own-root seedlings, NaCl stress reduced the chlorophyll content and photosynthetic rate, but increased the O2* producing rate and the H2O2 and MDA contents significantly. However, the growth of grafted seedlings was less affected by NaCl stress. The stronger salt tolerance of grafted eggplant seedlings was related to their higher antioxidant enzyme activities and less oxidative damage.

Novel 3-oxa lipoxin A4 analogues with enhanced chemical and metabolic stability have anti-inflammatory activity in vivo.

Lipoxin A(4) (LXA(4)) is a structurally and functionally distinct natural product called an eicosanoid, which displays immunomodulatory and anti-inflammatory activity but is rapidly metabolized to inactive catabolites in vivo. A previously described analogue of LXA(4), methyl (5R,6R,7E,9E,11Z,13E,15S)-16-(4-fluorophenoxy)-5,6,15-trihydroxy-7,9,11,13-hexadecatetraenoate (2, ATLa), was shown to have a poor pharmacokinetic profile after both oral and intravenous administration, as well as sensitivity to acid and light. The chemical stability of the corresponding E,E,E-trien-11-yne analogue, 3, was improved over 2 without loss of efficacy in the mouse air pouch model of inflammation. Careful analysis of the plasma samples from the pharmacokinetic assays for both 2 and 3 identified a previously undetected metabolite, which is consistent with metabolism by beta-oxidation. The formation of the oxidative metabolites was eliminated with the corresponding 3-oxatetraene, 4, and the 3-oxatrien-11-yne, 5, analogues of 2. Evaluation of 3-oxa analogues 4 and 5 in calcium ionophore-induced acute skin inflammation model demonstrated similar topical potency and efficacy compared to 2. The 3-oxatrien-11-yne analogue, 5, is equipotent to 2 in an animal model of inflammation but has enhanced metabolic and chemical stability and a greatly improved pharmacokinetic profile.

Structure function differences in nonpeptide CCR1 antagonists for human and mouse CCR1.

A useful strategy for identifying ligand binding domains of G protein-coupled receptors has been the exploitation of species differences in antagonist potencies. We have used this approach for the CCR1 chemokine receptor with a novel series of antagonists, the 4-hydroxypiperidines, which were discovered by high throughput screening of human CCR1 and subsequently optimized. The structure-activity relationships for a number of different 4-hydroxypiperidine antagonists for human and mouse CCR1 were examined by receptor binding and functional assays. These compounds exhibit major differences in their rank order of potency for the human and mouse chemokine receptor CCR1. For example, the initial lead template, BX 510, which was a highly potent functional antagonist for human CCR1 (K(i) = 21 nM) was >400-fold less active on mouse CCR1 (K(i) = 9150 nM). However, increasing the length of the linker between the piperidine and dibenzothiepine groups by one methylene group generated a compound, BX 511, which was equipotent for both human and mouse CCR1. These and other analogs of the lead template BX 510, which have major differences in potency for human and mouse CCR1, are described, and a model for their interaction with human CCR1 is presented.