Səhifə 1 dan 61 nəticələr
Here we have examined the composition of free sterols and steryl esters of pollen from selected angiosperm species, as a first step towards a comprehensive analysis of sterol biogenesis in the male gametophyte. We detected four major sterol structural groups: cycloartenol derivatives bearing a
The γ-keto triazole derivative 4,4-dimethyl-1-(2-methoxyphenyl)-1-(1,2,4-triazol-1-yl)-1-penten-3-one is toxic to Nicotiana tabacum L. cv. Xanthi plants or cell cultures. Analysis of the sterol composition of treated wild-type plant material demonstrates that this herbicide is an inhibitor of the
Heligmosomoides polygyrus bakeri is a model parasitic hookworm used to study animal and human helminth diseases. During infection, the parasite releases excretory/secretory products that modulate the immune system of the host. The most abundant protein family in excretory/secretory products
Two methyl transfers are involved in the course of plant sterol biosynthesis and responsible for the formation of 24-alkyl sterols (mainly 24-ethyl sterols) which play major roles in plant growth and development. The first methyl transfer applies to cycloartenol, the second one to 24-methylene
Obtusifoliol-14alpha-demethylase (CYP51) is implicated in plant sterol biosynthesis. An Arabidopsis expressed sequence tag encoding a CYP51 was used as a probe to isolate Nicotiana tabacum L. cDNAs. Two types of cDNA clones were identified. Nt CYP51-1 and Nt CYP51-2 shared 97% identity together and
Brassinosteroids (BRs) are an important class of plant steroidal hormones that are essential in a wide variety of physiological processes. Two kinds of intermediates, sitosterol and campesterol, play a crucial role in cell elongation, cellulose biosynthesis, and accumulation. To illuminate the
The plant sterol pathway exhibits a major biosynthetic difference as compared with that of metazoans. The committed sterol precursor is the pentacyclic cycloartenol (9β,19-cyclolanost-24-en-3β-ol) and not lanosterol (lanosta-8,24-dien-3β-ol), as it was shown in the late sixties. However, plant
In plants, the conversion of cycloartenol into functional phytosterols requires the removal of the two methyl groups at C-4 by an enzymic complex including a sterol 4alpha-methyl oxidase (SMO). We report the cloning of candidate genes for SMOs in Arabidopsis thaliana, belonging to two distinct
Higher plant cells contain a mixture of 24-desmethyl, 24-methyl(ene), and 24-ethyl(idene) sterols in given proportions according to species but also to cell type. As a first step to investigate the function of such sterol compositions in the physiology of a plant, we have illustrated in the present
The identity, composition, and concentration of the total, free, esterified, and glycosidic sterol fractions were determined during germination of tobacco seeds. The total, free, and esterified sterols increased, with stigmasterol and campesterol accounting for most of the increase. Steryl
The accumulation and biosynthesis of sterols and fungal elicitor-inducible sesquiterpenoids by tobacco (Nicotiana tabacum) cell suspension cultures were examined as a function of a 10 day culture cycle. Sterols accumulated concomitantly with fresh weight gain. The rate of sterol biosynthesis,
Transgenic tobacco (Nicotiana tabacum L.) plants with altered sterol composition were generated by transformation with plant cDNAs encoding type-1 and type-2 sterol methyltransferases (SMTs; EC 2.1.1.41). For both SMT1 and SMT2 transformants, the transformation was associated with a reduction in the
Three plant-growth retardants 2'-isopropy1-4'-(trimethylammonium chloride)-5-methylphenylpiperidine carboxylate (Amo 1618), beta-chloroethyltrimethylammonium chloride, and tributyl-2, 4-dichlorobenzylphosphonium chloride were tested for their effects on sterol production in, and growth of tobacco
Plant-microbe interactions involve numerous regulatory systems essential for plant defense against pathogens. An ethylene-inducing xylanase (Eix) of Trichoderma viride is a potent elicitor of plant defense responses in specific cultivars of tobacco (Nicotiana tabacum) and tomato (Solanum
A genomic fragment encoding one (HMGR1) of the three 3-hydroxy-3-methylglutaryl coenzyme A reductases (HMGRs) from Hevea brasiliensis (H.B.K.) Mull. Arg. (M.-L. Chye, C.-T. Tan, N.-H. Chua [1992] Plant Mol Biol 19: 473-484) was introduced into Nicotiana tabacum L. cv xanthi via Agrobacterium