K+(Rb+) and Ca2+ fluxes in young winter wheat plants exposed to sub-zero temperatures

Ice crystal formation temperature was determined in the region of the crown in one group of 7-day-old intact unhardened high-salt plants of winter wheat (Triticum aestivum L. cv. Weibulls Starke II) with TA (Thermal Analysis) and DTA (Differential Thermal Analysis) methods. After exposure of another group of plants, grown for the first 7 days in the same way as the first group, to various sub-zero temperatures (-1 to 5°C), influx in roots of Rb⁺(⁸⁶Rb⁺) and Ca²⁺(⁴⁵Ca²⁺) and contents of K⁺ and Ca²⁺ were determined at intervals during 7 days of recovery. Ice crystal formation in the crown tissue was probably extracellular and took place at about -4°C. There was a large loss of K⁺ from the roots after treatment at sub-zero temperatures. This loss increased as the temperature of the sub-zero treatment decreased. During recovery, roots of plants exposed to -1, -2 and -3°C gradually reabsorbed K⁺. Reabsorption of K⁺ in roots of plants exposed to -4°C was greatly impaired. Rb⁺ influx decreased and Ca²⁺ influx increased after sub-zero temperature treatments of the plants. Active Rb⁺ influx mechanisms and active extrusion of Ca²⁺ were impaired or irreversibly damaged by the exposure. While Rb⁺ influx mechanisms were apparently repaired during recovery in plants exposed to temperatures down to -3°C, Ca²⁺ extrusion mechanisms were not. The temperature for ice crystal formation in the region of the crown tissue coincides with the temperature at which the plants lost the ability to reabsorb K⁺ and to repair Rb⁺ influx mechanisms during the recovery period. Plants were lethally damaged at temperatures below ?4°C.     

Concentrations of glandular kallikrein in human nasal secretions increase during experimentally induced allergic rhinitis

We have previously demonstrated that a mixture of bradykinin and lysylbradykinin is generated in nasal secretions during the immediate allergic response to allergen. The present studies were performed to determine whether glandular kallikrein plays a role in kinin formation during the allergic reaction. Allergic individuals (n = 7) and nonallergic controls (n = 7) were challenged intranasally with appropriate allergen, and nasal lavages obtained before and after challenge were assayed for immunoreactive glandular kallikrein as well as for histamine, kinins, and N-alpha-tosyl-L-arginine methyl esterase (TAME-esterase) activity. The increase in postchallenge immunoreactive glandular kallikrein levels above baseline was significantly greater (p less than 0.01) for the allergic group (16.3 +/- 14 ng/ml; means +/- SD) than for the nonallergic controls (1.0 +/- 1.9 ng/ml). Increased levels of immunoreactive glandular kallikrein correlated with increases in kinins, histamine, and TAME-esterase activity and with the onset of clinical symptoms. Characterization of immunoreactive glandular kallikrein purified from postchallenge lavages by immunoaffinity chromatography confirmed the identity of this material as an authentic glandular kallikrein on the basis of its inhibition by protease inhibitors and by monospecific antibody to tissue kallikrein, its chromatographic behavior on gel filtration, and its ability to generate lysylbradykinin from highly purified human low m.w. kininogen. The specific activity of this purified material, in terms of kinin generation from kininogen, was very similar to that for authentic glandular kallikrein, suggesting that most if not all of the immunoreactive material purified from nasal lavages represented active enzyme. Inhibition studies by using pooled postchallenge lavages suggest that the majority of the kinin generating activity in these samples was due to glandular kallikrein. We conclude, therefore, that glandular kallikrein is secreted during the allergic response and can contribute to the formation of the lysylbradykinin produced during the allergic reaction.     

Acetate production from lactate and glucose fermentation by Gluconobacter oxydans

Summary The production of acetate from the fermentation of lactate by Gluconobacter oxydans was studied. Batch experiments showed that glucose was the preferred substrate compared to lactate. A fed-batch culture was fed with a mixture of glucose and lactate followed by periodic addition of lactate. The maximum productivity of acetate was 0.16 g/l h but this value decreased during the fedbatch culture due to growth inhibition by acetate.     

Chiral samarium iodo and terbutylate derivatives as catalysts for MPV ketone reductions

Samarium iodo and terbutylate derivatives coordinated by various chiral ligands have been prepared and used in situ as new catalysts for MPV reductions of aromatic ketones. The most active catalyst is samarium terbutylate binaphtolate albeit with moderate enantioselectivity.     

Analysis of the binding of p-chlorophenyl-methoxybenzyl-ketoxime (CPMB-oxime) to mitochondrial cytochrome c reductase.

Cytochrome c reductase is inhibited by p-chlorophenyl-methoxybenzyl-ketoxime (CPMB-oxime). CPMB-oxime induces a red-shift of the reduced spectrum of cytochrome b. The inhibitor blocks the oxidation of ubihydroquinone at the QP center of this enzyme in a non-competitive way. The binding stoichiometry equals one inhibitor molecule per Qp center. The apparent Kd in a red-shift assay was 6.9 +/- 0.6 microM. All binding characteristics analysed in this study were very similar to those of the E-beta-methoxyacrylate inhibitors, although the chemical structure is different from these inhibitors. This result is interpreted as a support for the inhibitory mechanism based on the model of a 'catalytic switch' proposed recently for the E-beta-methoxyacrylate inhibitors (MOA-inhibitors (Brandt and von Jagow, Eur. J. Biochem.     

Toll-like receptor 4 deficiency: Smaller infarcts,but nogain in function

Backgound  

It has been reported that Toll-like receptor 4 (TLR4) deficiency reduces infarct size after myocardial ischemia/reperfusion (MI/R). However, measurement of MI/R injury was limited and did not include cardiac function. In a chronic closed-chest model we assessed whether cardiac function is preserved in TLR4-deficient mice (C3H/HeJ) following MI/R, and whether myocardial and systemic cytokine expression differed compared to wild type (WT).     

Teixeiria lusitanica, a new fossil flower from the Early Cretaceous of Portugal with affinities to Ranunculales

A charcoalified fossil flower bud of a new genus and species (Teixeiria lusitanica) is described from the Early Cretaceous of Portugal. The flower is actinomorphic and unisexually male. At the base of the bud there are several bracts of different sizes, which are followed by sepal-like and petal-like tepals. Bracts and perianth organs seem to be arranged spirally and to exhibit transitions between different organ categories. The androecium has numerous stamens in two sizes, but with unclear arrangement. Pollen is small and tricolpate with a perforate tectum and a densely columellate infratectal layer. No carpels or remains of carpels could be observed on the floral axis. Teixeiria lusitanica shows most affinities to members of Ranunculales. There are also some similarities with Berberidopsis (Berberidopsidaceae, Berberidopsidales) and members of the Saxifragales (Hamamelidaceae and Daphniphyllaceae).