Safety and immunogenicity of attenuated Salmonella enterica serovar Typhimurium delivering an HIV-1 Gag antigen via the Salmonella Type III secretion system.

Background: CKS257 (Salmonella typhimurium SL1344 DeltaphoP/phoQDelta aroA Deltaasd DeltastrA/strB pSB2131) is a live oral vaccine vector expressing HIV Gag.

Methods: HIV Gag was expressed as a fusion protein of a Salmonella Type III secretion system protein SopE, from a balanced lethal asd-based plasmid. Eighteen healthy adults were given single escalating oral doses of 5 x 10(6) to 1 x 10(10)CFU of CKS257 and were monitored for clinical events, shedding and immune responses.

Metabolite export of isolated guard cell chloroplasts of Vicia faba.

•  Stomatal opening is caused by guard cell swelling due to an accumulation of osmotica. We investigated the release of carbon from guard cell chloroplasts as a source for the production of organic osmotica. •  Photosynthetically active chloroplasts were isolated from guard cell protoplasts of Vicia faba.

Alternation of the slow with the quick anion conductance in whole guard cells effected by external malate.

In previous investigations two anion conductances were discovered in guard-cell protoplasts: the quickly activating anion conductance (QUAC, R-type) and the slowly activating anion conductance (SLAC, S-type). In this investigation, effects of malate on the two anion conductances were tested in whole guard cells of Vicia faba L. by the use of the discontinuous single-electrode voltage-clamp method.

The slow and the quick anion conductance in whole guard cells: their voltage-dependent alternation, and the modulation of their activities by abscisic acid and CO2.

We explored the functioning of the slowly activating anion conductance, S-type or SLAC, and of the quickly activating anion conductance, R-type or QUAC, in whole guard cells of Vicia faba L.; details of QUAC activity had not previously been demonstrated in guard cells possessing their walls. The discontinuous single-electrode voltage-clamp method was used to record current responses to voltage pulses and voltage ramps as well as the free-running membrane voltage.

Traumatic brain injury and atrophy of the cingulate gyrus.

The medial surface areas of the cingulate gyrus (CG) and other midline structures (corpus callosum, thalamus, lateral ventricle) were examined in 27 traumatically brain injured (TBI) and 12 age- and gender-matched control subjects from an established TBI data base. Significant atrophy, primarily in the posterior CG, was found in TBI patients. Degree of atrophy was related to severity of injury.

Loading of nitrate into the xylem: apoplastic nitrate controls the voltage dependence of X-QUAC, the main anion conductance in xylem-parenchyma cells of barley roots.

We report here that NO(3)(-) in the xylem exerts positive feedback on its loading into the xylem through a change in the voltage dependence of the Quickly Activating Anion Conductance, X-QUAC. Properties of this conductance were investigated on xylem-parenchyma protoplasts prepared from roots of Hordeum vulgare by applying the patch-clamp technique. Chord conductances were minimal around -40 mV and increased with plasma membrane depolarisation as well as with hyperpolarisation.

Regulation of alpha1-proteinase inhibitor release by proinflammatory cytokines in human intestinal epithelial cells.

alpha1-Proteinase inhibitor (alpha1-PI) is the main serine proteinase inhibitor in human plasma. Apart from its synthesis in the liver, this anti-inflammatory protein is also synthesized by and excreted from human intestinal epithelial cells. Antiinflammatory actions of alpha1-PI are thought to be of relevance in the pathogenesis of inflammatory bowel disease.

The delivery of salts to the xylem. Three types of anion conductance in the plasmalemma of the xylem parenchyma of roots of barley.

To explore possible pathways for anions to enter the xylem in the root during the transport of salts to the shoot, we used the patch-clamp method on protoplasts prepared from the xylem parenchyma of barley (Hordeum vulgare L.) plants. K(+) currents were suppressed by tetraethylammonium or N-methylglucamine in the solutions in the pipette and the bath, and the permeating anions were Cl(-) or NO(3)(-).

Rates of sugar uptake by guard cell protoplasts of pisum sativum L. Related To the solute requirement for stomatal opening.

We wished to determine whether the capacity of the sugar uptake mechanisms of guard cells of the Argenteum mutant of pea (Pisum sativum L.) sufficed to support a concurrent stomatal opening movement. Sugar uptake by guard cell protoplasts was determined by silicone-oil-filtering centrifugation.

Solute accumulation and decreased photosynthesis in leaves of potato plants expressing yeast-derived invertase either in the apoplast, vacuole or cytosol.

Potato (Solanum tuberosum cv. Désirée) plants expressing yeast invertase directed either to the apoplast, vacuole or cytosol were biochemically and physiologically characterised. All lines of transgenic plants showed similarities to plants growing under water stress.

Properties of the K+ inward rectifier in the plasma membrane of xylem parenchyma cells from barley roots: effects of TEA+, Ca2+, Ba2+ and La3+.

Xylem parenchyma cells are situated around the (apoplastic) xylem vessels and are involved in the control of the composition of the xylem sap by exporting and resorbing solutes. We investigated properties of the K+ inward rectifier in the plasma membrane of these cells by performing patch clamp experiments on protoplasts in the whole-cell configuration. Inward currents were sensitive to the K+ channel blocker TEA+ at a high concentration (20 mM).

Ion Channels in the Xylem Parenchyma of Barley Roots (A Procedure to Isolate Protoplasts from This Tissue and a Patch-Clamp Exploration of Salt Passageways into Xylem Vessels.

To identify mechanisms for the simultaneous release of anions and cations into the xylem sap in roots, we investigated voltage-dependent ion conductances in the plasmalemma of xylem parenchyma cells. We applied the patch-clamp technique to protoplasts isolated from the xylem parenchyma by differential enzymic digestion of steles of barley roots (Hordeum vulgare L. cv Apex).

Phosphate Translocator of Isolated Guard-Cell Chloroplasts from Pisum sativum L. Transports Glucose-6-Phosphate.

Chloroplasts were isolated from ruptured guard-cell protoplasts of the Argenteum mutant of Pisum sativum L. and purified by centrifugation through a Percoll layer. The combined volume of the intact plastids and the uptake of phosphate were determined by silicone oil-filtering centrifugation, using tritiated water and [14C]sorbitol as membrane-permeating and nonpermeating markers and [32P]phosphate as tracer for phosphate.

A slow anion channel in guard cells, activating at large hyperpolarization, may be principal for stomatal closing.

Slowly activating anion channel currents were discovered at micromolar 'cytoplasmic' Ca2+ during patch-clamp measurements on guard-cell protoplasts of Vicia faba and Xanthium strumarium. They activated at potentials as low as -200 mV, with time constants between 5 and 60 s, and no inactivation. The broad voltage dependence exhibited a current maximum near -40 mV.

Apoplastic expression of yeast-derived invertase in potato : effects on photosynthesis, leaf solute composition, water relations, and tuber composition.

In potato plants (Solanum tuberosum), a chimeric yeast-derived invertase gene fused to a 35S cauliflower mosaic virus promoter has been expressed. The protein was targeted to the cell wall by using the signal peptide of proteinase inhibitor II fused to the amino terminus of the yeast invertase. The transformed plants had crinkled leaves, showed a reduced growth rate, and produced fewer tubers.

Ca2+ and nucleotide dependent regulation of voltage dependent anion channels in the plasma membrane of guard cells.

Using the patch-clamp technique we discovered that the voltage dependent anion channels in the plasma membrane of guard cells are activated by a rise in cytoplasmic Ca2+ in the presence of nucleotides. Upon activation, these anion channels catalyse anion currents 10-20 times higher than in the inactivated state, thus shifting the plasma membrane from a K+ conducting state to an anion conducting state. Prolonged stimulation by depolarizing voltages results in the inactivation of the anion current (t1/2 = 10-12 s).

Control of photosynthesis in leaves as revealed by rapid gas exchange and measurements of the assimilatory force FA.

The rapid transients of CO2 gas exchange have been measured in leaves ofHelianthus annuus L. In parallel experiments the assimilatory force FA, which is the product of the phosphorylation potential and the redox ratio NADPH/NADP, has been calculated from measured ratios of dihydroxyacetone phosphate to phosphoglycerate in the chloroplast stroma and in leaves. The following results were obtained: (i) When the light-dependent stroma alkalization was measured under steady-state conditions for photosynthesis in air containing 2000 μl · l(-1) CO2, alkalization increased with photosynthesis as the quantum flux density (irradiance) was increased.

Malate Dehydrogenases in Guard Cells of Pisum sativum.

Guard cell protoplasts of Pisum sativum show considerable NADP-dependent malate dehydrogenase (MDH) activity in darkness which can be enhanced severalfold by illumination or treatment with dithiothreitol (DTT). The question arose whether guard cells possess an NADP-MDH different from that present in the chloroplasts of the mesophyll (which is inactive in darkness or in the absence of DTT). MDH activities were determined in extracts of isolated protoplasts from mesophyll and epidermis, and in mechanically prepared epidermal pieces (with guard cells as the only living cells and no interference from proteases originating from the cell wall digesting enzymes).

Rubisco activity in guard cells compared with the solute requirement for stomatal opening.

We investigated whether the reductive pentose phosphate path in guard cells of Pisum sativum had the capacity to contribute significantly to the production of osmotica during stomatal opening in the light. Amounts of ribulose 1,5-bisphophate carboxylase/oxygenase (Rubisco) were determined by the [(14)C]carboxyarabinitol bisphosphate assay. A guard cell contained about 1.

Topography of photosynthetic activity of leaves obtained from video images of chlorophyll fluorescence.

The distribution of photosynthetic activity over the area of a leaf and its change with time was determined (at low partial pressure of O(2)) by recording images of chlorophyll fluorescence during saturating light flashes. Simultaneously, the gas exchange was being measured. Reductions of local fluorescence intensity quantitatively displayed the extent of nonphotochemical quenching; quench coefficients, q(N), were computed pixel by pixel.

The state of the photosynthetic apparatus in leaves as analyzed by rapid gas exchange and optical methods: the pH of the chloroplast stroma and activation of enzymes in vivo.

The exchange of CO2 and O2 was measured in leaves using specially constructed equipment capable of responding to rapid transients. Optical measurements provided information on cytochrome f and P 700 oxidation in the light. The following results were obtained: i) The solubilization of CO2 was used to calculate the pH of the chloroplast stroma in darkened leaves.

Abscisic-acid contents and concentrations in protoplasts from guard cells and mesophyll cells ofVicia faba L.

The abscisic-acid (ABA) contents of isolated guard-cell protoplasts and mesophyll-cell protoplasts fromVicia faba were determined by high-pressure liquid chromatography followed by gas chromatography. The amounts of ABA found immediately after preparation of the protoplasts varied from 90 to 570 amol per guard-cell protoplast, and from 75 to 100 amol per mesophyll-cell protoplast. These contents correspond to concentrations between 36 and 230 μmol per liter in guard-cell protoplasts and between 2.

Induction of a high-capacity nitrate-uptake mechanism in barley roots prompted by nitrate uptake through a constitutive low-capacity mechanism.

Roots of nitrate-starved and nitrate-pretreated seedlings of Hordeum vulgare were used to investigate the induction of a high-capacity uptake mechanism for nitrate. When exposed to 0.2 mmol·l(-1)KNO3, nitrate-starved roots took up nitrate at a rate of approx.