Amino acids (AAs), important constituents of natural moisturizing factors (NMFs) of the skin are decreased in diseased conditions such as psoriasis and atopic dermatitis. No study so far investigated the uptake of AAs into isolated corneocytes (COR). The present study was performed using 19 AAs, including taurine (TAU), to measure their amount diffused into the COR and binding of these AAs to keratin. Incubation of alanine, aspartic acid, asparagine, glutamine, glutamic acid, histidine, proline, serine and TAU with the isolated COR showed uptake after 24 h of 51.6, 95.4, 98.6, 94.1, 95.6, 90.1, 94.6, 72.9 and 57.8 %, respectively, into the COR but no binding with keratin. Uptake of TAU was validated by time dependent in-vitro diffusion models 'without COR and 'with COR'. The time dependent curve fitting showed that in in-vitro diffusion model 'without COR' there was no change in the total concentration of TAU until 72 hours, while in diffusion model 'with COR' the total conc. decreased to 37.8 % after 72 hours. The Pearson's correlation coefficient 'r' between the conc. curves of both in-vitro diffusion models was -0.54 that was an evidence of significant amount of TAU uptake by the COR. AAs as part of the NMFs have a great potential to be diffused into the COR. This property of the AAs can be employed in further dermatological research on diseased or aged skin conditions with NMFs deficiency.

Hydnora abyssinica A.Br. (Hydnoraceae), a holoparasitic herb, is for the first time recorded for Abyan governorate of South Yemen. Flowers of this species were studied for their ethnobotanical, biological and chemical properties for the first time. In South Yemen, they are traditionally used as wild food and to cure stomach diseases, gastric ulcer and cancer. Phytochemical analysis of the extracts showed the presence of terpenes, tannins, phenols, and flavonoids. The volatile components of the air-dried powdered flowers were identified using a static headspace GC/MS analysis as acetic acid, ethyl acetate, sabinene, α-terpinene, (+)-D-limonene and γ-terpinene. These volatile compounds that characterize the odor and taste of the flowers were detected for the first time in a species of the family Hydnoraceae. The flowers were extracted by n-hexane, dichlormethane, ethyl acetate, ethanol, methanol and water. With exception of the water extract all extracts demonstrated activities against Gram-positive bacteria as well as remarkable radical scavenging activities in DPPH assay. Ethyl acetate, methanol and water extracts exhibited good antifungal activities. The cytotoxic activity of the extracts against FL cells, measured in neutral red assay, was only weak (IC50 > 500 μg /mL). The results justify the traditional use of the flowers of Hydnora abyssinica in South Yemen.

Leaf senescence is the final developmental stage of a leaf. The progression of barley primary leaf senescence was followed by measuring the senescence‐specific decrease in chlorophyll content and photosystem II efficiency. In order to isolate novel factors involved in leaf senescence, a differential display approach with mRNA populations from young and senescing primary barley leaves was applied. In this approach, 90 senescence up‐regulated cDNAs were identified. Nine of these clones were, after sequence analyses, further characterized. The senescence‐associated expression was confirmed by Northern analyses or quantitative RealTime‐PCR. In addition, involvement of the phytohormones ethylene and abscisic acid in regulation of these nine novel senescence‐induced cDNA fragments was investigated. Two cDNA clones showed homologies to genes with a putative regulatory function. Two clones possessed high homologies to barley retroelements, and five clones may be involved in degradation or transport processes. One of these genes was further analysed. It encodes an ADP ribosylation factor 1‐like protein (HvARF1) and includes sequence motifs representing a myristoylation site and four typical and well conserved ARF‐like protein domains. The localization of the protein was investigated by confocal laser scanning microscopy of onion epidermal cells after particle bombardment with chimeric HvARF1‐GFP constructs. Possible physiological roles of these nine novel SAGs during barley leaf senescence are discussed.

Phytohormones are not only instrumental in regulating developmental processes in plants but also play important roles for the plant's responses to biotic and abiotic stresses. In particular, abscisic acid, ethylene, jasmonic acid, and salicylic acid have been shown to possess crucial functions in mediating or orchestrating stress responses in plants. Here, we review the role of salicylic acid and jasmonic acid in pathogen defence responses with special emphasis on their function in the solanaceous plant potato.

Among the plant hormones jasmonic acid and related derivatives are known to mediate stress responses and several developmental processes. Biosynthesis, regulation, and metabolism of jasmonic acid in Arabidopsis thaliana are reviewed, including properties of mutants of jasmonate biosynthesis. The individual signalling properties of several jasmonates are described.

Chemical investigation of Stephania rotunda Lour. growing in Viet Nam led to the isolation and structural elucidation of three new alkaloids, 5-hydroxy-6,7-dimethoxy-3,4-dihydroisoquinolin-1(2H)-one (1), thaicanine 4-O-β-L-glucoside (6), as well as (–)-thaicanine N-oxide (4-hydroxycorynoxidine) (8), along with 23 known alkaloids. These structures were determined on the basis of MS and NMR spectroscopic data.

Transport processes between plant and fungal cells are key elements in arbuscular mycorrhiza (AM), where H+‐ATPases are considered to be involved in active uptake of nutrients from the symbiotic interface. Genes encoding H+‐ATPases were identified in the genome of Medicago truncatula and three cDNA fragments of the H+‐ATPase gene family (Mtha 1 ‐ 3) were obtained by RT‐PCR using RNA from M. truncatula mycorrhizal roots as template. While Mtha 2 and Mtha 3 appeared to be constitutively expressed in roots and unaffected by AM development, transcripts of Mtha 1 could only be detected in AM tissues and not in controls. Further analyses by RT‐PCR revealed that Mtha 1 transcripts are not detectable in shoots and phosphate availability did not affect RNA accumulation of the gene. Localization of transcripts by in situ hybridization on AM tissues showed that Mtha 1 RNA accumulates only in cells containing fungal arbuscules. This is the first report of arbuscule‐specific induced expression of a plant H+‐ATPase gene in mycorrhizal tissues.

2,4-Dimethoxy-2-methyl-6H-pyran-3-one (1), a hitherto unknown natural product, and the calcium salt of rehmapicroside (2) have been isolated from rhizomes of the Vietnamese variety of Rehmannia glutinosa Libosch together with a series of known compounds: norcarotenoids (3–5), 2-formyl-5-hydroxymethylfurane (6), the iridoid rehmaglutin D (7), iridoid glycosides (8–12) and phenylethyl alcohol glycosides (13–17). Their structures were determined by mass and NMR spectroscopy.

Conventional and analytical electron microscopy (EDX, ESI, EELS) were used to investigate the silicon accumulation, the chemical nature of the Si deposits and their formation in three species of monocotyledons. In Deschampsia , in particular parts of the outer epidermal cell wall silicon is accumulated as silicic acid. Electron dense, needle‐shaped crystals in the vacuoles of epidermal cells and in the intercellular spaces were also identified as silicic acid. In xylem parenchyma cells, silicon is accumulated as SiO2, which is formed from Sn silicate. In Festuca , crystal‐like deposits of SiO2 occur on the epidermal surface, in the epidermal and parenchyma cell walls, and in vacuoles of bundle sheath cells. Often the deposits disturb the cell walls and penetrate the envelope of plastids and mitochondria. The crystal‐like SiO2 deposits originate from Sn silicate. In the pericarp of ripe nuts of Schoenus , no stainable cell wall components are detected. The inner part of the pericarp consists of silicic acid, while in the outer regions small clusters of silicic acid are embedded in a matrix of SiO2. The silicic acid deposits show an unusual, layered structure, typical for lepidoic silicic acids, which consist of two‐dimensional crystals lying one above the other.

Treatment of barley leaf segments with jasmonic acid methyl ester (JM) leads to the accumulation of a set of newly formed abundant proteins. Among them, the most abun dant protein exhibits a molecular mass of 23 kDa (JIP‐23). Here, data are presented on the occurrence and expression of the lIP‐23 genes in different cultivars of Hordeum vulgare . Southern blot analysis of 80 cultivars revealed the occurrence of 2 to 4 genes coding for JIP‐23 in all cultivars. By means of Northern blot and immunoblot analysis it is shown that some cultivars lack the ex pression of jip‐23 upon treatment of primary leaves with JM as well as upon stress performed by incubation with 1 M sorbitol solution. During germination, however, all tested cultivars ex hibited developmental expression of jip‐23 . The results are dis cussed in terms of possible functions of JIP‐23 in barley.