Quantification of cuticular permeability in genetically modified plants.

More and more studies on genetically modified plants are identifying parts of the genetic code with putative involvement in creating the cuticular barrier. Unfortunately, many of these studies suffer from the inadequacy of the chosen methods to quantify, in a reasonably unambiguous way, if and how the efficacy of the cuticular barrier is affected by the genetic change. A short overview of relevant findings is given and a more stringent experimental approach to quantifying effects on cuticular permeability in genetically modified plants proposed.

The short-term growth response to salt of the developing barley leaf.

Recent results concerning the short-term growth response to salinity of the developing barley leaf are reviewed. Plants were grown hydroponically and the growth response of leaf 3 was studied between 10 min and 5 d following addition of 100 mM NaCl to the root medium. The aim of the experiments was to relate changes in variables that are likely to affect cell elongation to changes in leaf growth.

Bauhin's ileocecal valve syndrome-a rare cause for small-bowel obstruction: report of a case.

Benign ileocecal valve hypertrophy is a rare cause for intestinal obstruction. We describe a 51-year-old female with clinical and imaging presentation of chronic small-bowel obstruction. The patient was operated on, and a limited thickening of the ileocecal bowel wall causing intestinal obstruction was found.

An in vitro study on the postinfection activities of copper hydroxide and copper sulfate against conidia of Venturia inaequalis.

The postinfection activities of copper hydroxide [Cu(OH)2] and copper sulfate (CuSO4) against apple scab (Venturia inaequalis) were evaluated in an in vitro study. Our intention was to support the aim of reducing copper application rates by appropriate timing of applications. Experiments were conducted at 20 degrees C with leaf disks and isolated cuticular membranes (CM) of Malus x domestica 'Gloster' and 'Elstar'.

Epiphytic microorganisms on strawberry plants (Fragaria ananassa cv. Elsanta): identification of bacterial isolates and analysis of their interaction with leaf surfaces.

Epiphytic bacteria were isolated from strawberry plants cultivated in the field or in the greenhouse in order to investigate their interaction with leaf-surface transport properties. Colonization of lower leaf sides was higher on field-grown plants, whereas upper leaf sides were more densely colonized on plants cultivated in the greenhouse. Fungal isolates significantly contributed to total microbial biomass on leaf surfaces of greenhouse-grown strawberry plants, whereas these organisms were rarely abundant on field-grown plants.

Effects of hypergravity conditions on elongation growth and lignin formation in the inflorescence stem of Arabidopsis thaliana.

The effects of hypergravity on elongation growth and lignin deposition in secondary cell walls of the Arabidopsis thaliana (L.) Heynh. inflorescence stem were examined in plants grown for 3 days after exposure to hypergravity in the direction from shoot to root at 300 g for 24 h.

Modelling the effects of alcohol ethoxylates on diffusion of pesticides in the cuticular wax of Chenopodium album leaves.

Cuticular waxes represent the first and, in most cases, the limiting barrier for foliar uptake of pesticides from solution. Sorption of pesticides in reconstituted cuticular wax (wax/water partition coefficients) of Chenopodium album L. and in isolated cuticular membranes (cuticle/water partition coefficients) of Prunus laurocerasus L.

Apoplastic polyesters in Arabidopsis surface tissues--a typical suberin and a particular cutin.

Cutinized and suberized cell walls form physiological important plant-environment interfaces as they act as barriers limiting water and nutrient loss and protect from radiation and invasion by pathogens. Due to the lack of protocols for the isolation and analysis of cutin and suberin in Arabidopsis, the model plant for molecular biology, mutants and transgenic plants with a defined altered cutin or suberin composition are unavailable, causing that structure and function of these apoplastic barriers are still poorly understood. Transmission electron microscopy (TEM) revealed that Arabidopsis leaf cuticle thickness ranges from only 22 nm in leaf blades to 45 nm on petioles, causing the difficulty in cuticular membrane isolation.

Casparian strips in needles are more solute permeable than endodermal transport barriers in roots of Pinus bungeana.

The structure and development of endodermal Casparian strips in Pinus bungeana needles and roots were studied by scanning electron microscopy and fluorescence microscopy. Primary pit fields (PFs) frequently occurred in radial walls of Casparian strips isolated from needles, whereas PFs were never detected in Casparian strips from roots. Formation of Casparian strips in needles as well as roots started at the outer parts of the radial walls and they finally occupied the entire radial walls of the endodermis.

AgCl precipitates in isolated cuticular membranes reduce rates of cuticular transpiration.

Counter diffusion of chloride, applied as NaCl at the inner side of isolated cuticles, and silver, applied as AgNO(3) at the outer side, lead to the formation of insoluble AgCl precipitates in isolated cuticles. AgCl precipitates could be visualized by light and scanning electron microscopy. The presence of AgCl precipitates in isolated cuticles was verified by energy dispersive X-ray analysis.

Comparison of sorption and diffusion by pyridate and its polar metabolite in isolated cuticular wax of Chenopodium album and Hordeum vulgare.

Sorption and diffusion of the herbicide pyridate and its metabolite CL9673 were measured in reconstituted cuticular waxes isolated from Chenopodium album L. and Hordeum vulgare L. (cultivar Igri) leaves.

Detection of calretinin expression in abnormal immature Sertoli cells in non-obstructive azoospermia.

The current study identified for the first time calretinin expression in abnormal Sertoli cells of azoospermic men who underwent testicular biopsy for sperm recovery and application of the retrieved sperm by in vitro fertilization techniques. Testicular biopsies with various spermatogenic impairments were evaluated immunohistochemically for the expression of the calretinin calcium-binding protein and the marker for immaturity of Sertoli cells, cytokeratin-18 (CK-18). Distribution of the markers was assessed in testes demonstrating a histological phenotype of mixed atrophy, Sertoli cell-only, or normal spermatogenesis (obstructive-azoospermia) and in men carrying a deletion in the azoospermia factor region located on the Y chromosome.

Cuticular wax deposition in growing barley (Hordeum vulgare) leaves commences in relation to the point of emergence of epidermal cells from the sheaths of older leaves.

In grasses, leaf cells divide and expand within the sheaths of older leaves, where the micro-environment differs from the open atmosphere. By the time epidermal cells are displaced into the atmosphere, they must have a functional cuticle to minimize uncontrolled water loss. In the present study, gas chromatography and scanning electron microscopy were used to follow cuticular wax deposition along the growing leaf three of barley (Hordeum vulgare L.

Rates of cuticular penetration of chelated Fe(III): role of humidity, concentration, adjuvants, temperature, and type of chelate.

Time courses of cuticular penetration of FeCl3 and Fe(III) complexes of citric acid, EDTA, EDDHA (Sequestrene 138Fe), imidodisuccinic acid (IDHA), and ligninsulfonic acid (Natrel) were studied using astomatous cuticular membranes (CMs) isolated from Populus x canescens leaves. At 100% relative humidity, the Fe(III) chelates disappeared exponentially with time from the surface of the CMs; that is, penetration was a first-order process that can be described using rate constants or half-times of penetration (t(1/2)). Half-times ranged from 20 to 30 h.

CYP94A1, a plant cytochrome P450-catalyzing fatty acid omega-hydroxylase, is selectively induced by chemical stress in Vicia sativa seedlings.

CYP94A1 is a cytochrome P450 (P450) catalyzing fatty acid (FA) omega-hydroxylation in Vicia sativa seedlings. To study the physiological role of this FA monooxygenase, we report here on its regulation at the transcriptional level (Northern blot). Transcripts of CYP94A1, as those of two other P450-dependent FA hydroxylases (CYP94A2 and CYP94A3) from V.

Effects of hypergravity environment on lignin formation in Arabidopsis.

Lignin and the secondary wall formation are essential for evolution of land plants. In this study, effects of hypergravity environment on the morphology of the secondary wall and the lignin content were examined in Arabidopsis thaliana. Xylem vessels showed intense staining with phloroglucinol-HCl and autofluorescence under UV light at the basal region of the flower stalk when seedlings grown for 3 days after hypergravity treatment for 24 hours.

Plant-microbe interactions: identification of epiphytic bacteria and their ability to alter leaf surface permeability.

Bacteria were either isolated from leaf surfaces of Hedera helix or obtained from a culture collection in order to analyse their effect on barrier properties of isolated Hedera and Prunus laurocerasus cuticles. On the basis of the 16S rDNA sequences the genera of the six bacterial isolates from Hedera were identified as Pseudomonas sp., Stenotrophomonas sp.

The chemical composition of suberin in apoplastic barriers affects radial hydraulic conductivity differently in the roots of rice (Oryza sativa L. cv. IR64) and corn (Zea mays L. cv. Helix).

Apoplastic transport barriers in the roots of rice (Oryza sativa L. cv. IR64) and corn (Zea mays L.

Functional conservation and maintenance of expression pattern of FIDDLEHEAD-like genes in Arabidopsis and Antirrhinum.

In Arabidopsis, loss of function of the epidermis-specific FDH gene coding for a putative beta-ketoacyl-CoA synthase results in ectopic organ fusions in mutants. Corresponding mutants are not available for Antirrhinum majus, however, organ fusions can be induced in both species by chloroacetamide inhibitors of beta-ketoacyl-CoA synthases using a chemical genetics approach. We isolated the ortholog of FDH from Antirrhinum majus, the ANTIRRHINUM FIDDLEHEAD (AFI ) gene, and showed that AFI complements fdh when expressed in the epidermis under control of the FDH promoter.

Polar paths of diffusion across plant cuticles: new evidence for an old hypothesis.

Background: The plant cuticle is an extracellular lipophilic biopolymer covering leaf and fruit surfaces. Its main function is the protection of land-living plants from uncontrolled water loss. In the past, the permeability of the cuticle to water and to non-ionic lipophilic molecules (pesticides, herbicides and other xenobiotics) was studied intensively, whereas cuticular penetration of polar ionic compounds was rarely investigated.

Accelerators increase permeability of cuticles for the lipophilic solutes metribuzin and iprovalicarb but not for hydrophilic methyl glucose.

Effects of diethylsuberate (DESU), tributyl phosphate (TBP), and monodisperse ethoxylated alcohols (EAs) on rate constants of penetration (k) of model solutes across astomatous cuticular membranes isolated from Madagascar ivy (Stephanotis floribunda) and pear (Pyrus communis) leaves were studied. Model solutes (selected on the basis of their octanol/water partition coefficients, K(ow)) were iprovalicarb (log K(ow) = 3.18), metribuzin (log K(ow) = 1.

Effects of accelerators on mobility of 14C-2,4-dichlorophenoxy butyric acid in plant cuticles depends on type and concentration of accelerator.

Effects of diethyl suberate (DESU), diethyl sebacate (DES), dibutyl suberate (DBSU), dibutyl sebacate (DBS), and tributyl phosphate (TBP) on diffusion of 14C-2,4-dichlorophenoxy butyric acid (2,4-DB) across cuticular membranes (CM) was studied. Astomatous CM were isolated enzymatically from Stephanotis floribunda Brongn. leaves, and diffusion was measured at 20 degrees C.

Sorption in reconstituted waxes of homologous series of alcohol ethoxylates and n-alkyl esters and their effects on the mobility of 2,4-dichlorophenoxybutyric acid.

Equilibrium sorption of n-alkyl esters (dimethyl suberate, diethyl suberate, diethyl sebacate, dibutyl suberate and dibutyl sebacate) and monodisperse alcohol ethoxylates (diethylene glycol, tetraethylene glycol, pentaethylene glycol, hexaethylene glycol and octaethylene glycol monododecyl ether) between the reconstituted cuticular waxes of Stephanotis floribunda Brongn (Madagascar jasmine) or Hordeum vulgare L (barley) leaves and an external aqueous receptor solution was determined. Logarithms of the wax/receptor partition coefficient (K(wax/rec)) of the n-alkyl esters increased linearly with the number of C-atoms. With alcohol ethoxylates, log K(wax/rec) decreased linearly with the number of ethylene oxide units.