Sesquiterpenoids from roots of Taraxacum laevigatum and Taraxacum disseminatum

Chromatographic separation of ethanolic root extracts of Taraxacum laevigatum and Taraxacum disseminatum afforded a total of eight germacrane- and eudesmane-type sesquiterpenoids. including new compounds, 1beta,3beta,6alpha-trihydroxy-4alpha( 15)-dihydrocostic acid methyl ester and its 1-O-beta-glucopyranoside. Their structures were established by spectroscopic analyses. In addition, the structure of 4alpha(15), 11beta(13)-tetrahydroridentin B-1-O-beta-glucopyranoside was elucidated by extensive NMR studies.     

Sesquiterpenoids and phenolics from Crepis mollis

From the roots of Crepis mollis, one new and two known guaianolides were isolated together with eight known guaianolide glycosides, one known germacranolide glycoside and two known phenylpropanoids. The structure and relative configuration of the new compound were established as 9alpha-hydroxy-4beta, 15, 11beta, 13-tetrahydro-dehydrozaluzanin C by spectral methods.     

Molecular modelling of the interaction of carbocyclic analogues of netropsin and distamycin with d(CGCGAATTCGCG)2

A molecular mechanics and molecular dynamics approach was used to examine the structure of complexes formed between the d(CGCGAATTCGCG)2 duplex and netropsin, distamycin, and four carbocyclic analogues of netropsin and distamycin (1-4). The resulting structures of the ligand-DNA model complexes and their energetics were examined. It is predicted that the compounds 1-4 should have a decreased affinity for the minor groove of AT-rich regions in comparison to netropsin and distamycin. From the energetic analysis it appears that van der Waals and electrostatic interactions are more important than specific hydrogen bonds in stabilizing the ligand-duplex complexes. We predict that compounds 1 and 2 are effectively isohelical with the DNA minor groove. The superior DNA-binding afforded by 1 and 2 in comparison to 3 and 4 results from their more effective penetration into the minor groove and smaller perturbation of molecular structure upon complex formation.     

Connexin43 in porcine myocardium and non-pregnant myometrium

It is generally accepted that connexin43 (Cx43) is a major constituent of heart and myometrial gap junctions. However, the presence of Cx43 gap junctions in non-pregnant myometrium is still poorly documented. Tissue sections of porcine heart and non-pregnant uterus and myometrial smooth muscle cell cultures were immunostained with monoclonal antibody against Cx43. In the heart, intensive immunostaining was confined to the intercalated discs as previously reported. In the non-pregnant uterus, punctuate immunostaining of Cx43 was seen throughout the myometrium along cell interfaces between myocytes. The expression of Cx43 was sustained in cultured smooth muscle cells isolated from non-pregnant myometrium. Western blotting has detected single isoform of Cx43 in both, cardiac and myometrial tissues. The electrophoretic mobility of porcine heart Cx43 was similar to that of myometrial isoform but different from the pattern of mobility of Cx43 of the rat heart. Hence, porcine myometrium may provide attractive model for studying cellular mechanisms triggering expression of gap junction protein in normal (non-pregnant) uterus.     

Lack of effects of glycineB receptor ligands on the psychostimulant-induced discriminative stimuli in rats

To examine the role of glycineB receptors in the stimulus effects induced by psychostimulants, separate groups of rats were trained to discriminate amphetamine (AMPH; 1 mg/kg) from saline (SAL), or cocaine (COC; 10 mg/kg) from SAL, using a two-lever operant procedure. Substitution studies showed that neither 1-aminocyclopropanecarboxylic acid (ACPC; 200 mg/kg) nor 7-chloro-4-hydroxy-3-(3-phenoxy)phenyl-(H)quinolone (L-701,324; 3 mg/kg), being a partial agonist or an antagonist at glycineB receptors, respectively, generalized for the training drugs. Combination tests of glycineB ligands demonstrated that injection of a fixed dose of ACPC (200 mg/kg) or L-701,324 (3 mg/kg) together with different doses of AMPH or COC practically did not modify dose-response curves of the psychostimulants, nor did it affect their ED50 values. Our results indicate that glycineB receptors do not play a role in the discriminative effects of AMPH and COC.     

Selective recovery of Zn2+ from waste slag from a metal-processing plant by the microscopic fungus Verticillium marquandii

The successful use of hay extract medium for growth of Verticillium marquandii in the presence of toxic black slag, resulted in selective and efficient Zn²⁺ recovery. An alkaline black waste slag originating from short rotary furnace, contained Zn²⁺ and Pb²⁺ (20% and 3.5%, respectively) in a form of compounds only slightly soluble in water. After 90 h of the culturing in bioreactor on hay extract medium with starch (50 g l^–1) and black waste (5 g l^–1) supplements, 80% of zinc and 0.5% of lead were bound by the mycelium. The pH value of the culture medium played a crucial role for limitation of the waste inhibitory effect on mycelium growth and for heavy metal recovery by the fungus.     

Low-molecular-weight organic acids in rhizosphere soils of durum wheat and their effect on cadmium bioaccumulation

Cadmium (Cd) accumulation has been found to vary between cultivars of durum wheat (Triticum turgidum var. durum), and it is hypothesized that low-molecular-weight organic acids (LMWOAs) produced at the soil-root interface (rhizosphere) may play an important role in the availability and uptake of Cd by these plants. The objective of this study, therefore, was to (1) investigate the nature and quantity of LMWOAs present in the rhizosphere of durum wheat cultivars Arcola (low Cd accumulator) and Kyle (high Cd accumulator) grown in three different soils: Yorkton, Sutherland and Waitville, and (2) determine the relationship between Cd accumulation in these plants and LMWOAs present in the rhizosphere. Plants were grown for two weeks in pot-cultures under growth chamber conditions. Oxalic, fumaric, succinic, L-malic, tartaric, citric, acetic, propionic and butyric acids were found and quantified in the water extracts of rhizosphere soil, with acetic and succinic acids being predominant. No water extractable LMWOAs were identified in the bulk soil. Total amount of LMWOAs in the rhizosphere soil of the high Cd accumulator (Kyle) was significantly higher than that for the low Cd accumulator (Arcola) in all three soils. Furthermore, large differences in amounts of LMWOAs were found in the rhizosphere soil for the same cultivars grown in different soils and followed the pattern: Sutherland > Waitville > Yorkton. Extractable soil Cd (M NH4Cl) and Cd accumulation in the plants also followed the same soil sequence as LMWOA production. Cadmium accumulation by the high and low Cd accumulating cultivars was proportional to the levels of LMWOAs found in the rhizosphere soil of each cultivar. These results suggest that the differing levels of LMWOAs present in the rhizosphere soil played an important role in the solubilization of particulate-bound Cd into soil solution and its subsequent phytoaccumulation by the high and low Cd accumulating cultivars.     

The isolation and in vitro culture of bovine preantral and early antral follicles of different size classes

The ovary of cattle contains thousands of oocytes which are enclosed primarily in the preantral follicles. Methods of culturing preantral follicles are now being developed. The aim of this study was to investigate the effect of the size of bovine preantral and early antral follicles and culture media on their in vitro growth. Individual follicles isolated by microdissection of the ovarian slices were sorted into the following size classes: 75 to 124, 125 to 174, 175 to 224, 225 to 274, 275 to 324 and > or = 325 microns. The follicles were cultured individually in TCM 199 + fetal calf serum (FCS) + supplements (FSH, estradiol-17 beta, insulin, transferrin, sodium selenite, sodium pyruvate, 1-glutamine and hypoxanthine) or in Menezo B2 + FCS + supplements (Experiment 1) and in TCM 199 + steer serum (SS) with or without additional supplements (Experiment 2). The total number of isolated follicles of different size classes was similar in heifers and cows. No significant difference in the growth rate of follicles of different sizes was seen in the 2 media (TC 199 and B2). However, the culture of follicles in the TCM 199 that was supplemented only with SS and contained no other additives significantly reduced follicular survival and growth in comparison with follicles cultured in the supplemented medium. The survival time of follicles was related to their initial size at the beginning of culture. The longest period of growth was for follicles 275 to 324 microns in diameter (i.e., 10.7 +/- 5.7; 12.1 +/- 6.2 and 12.2 +/- 2.7 d, respectively, for culture in supplemented Menezo B2, TCM 199 + FCS and TCM 199 + SS). Survival and growth of some follicles was maintained for 23 d.     

Effects of Aluminum and Calcium on Acetyl-CoA Metabolism in Rat Brain Mitochondria

Abstract: Al complexes are known to accumulate in extra- and intracellular compartments of the brain in the course of different encephalopathies. In this study possible effects of Al accumulation in the cytoplasmic compartment on mitochondrial metabolism were investigated. Al, like Ca, inhibited pyruvate utilization as well as citrate and oxoglutarate accumulation by whole brain mitochondria. Potencies of Ca²⁺_total effects were 10–20 times stronger than those of Al. Al decreased mitochondrial acetyl-CoA content in a concentration-dependent manner, along with an equivalent rise of free CoA level, whereas Ca caused loss of both intermediates from mitochondria. In the absence of P_i in the medium, Ca had no effect on mitochondrial metabolism, whereas Al lost its ability to suppress pyruvate utilization and acetyl-CoA content in Ca-free conditions. Verapamil potentiated, whereas ruthenium red reversed, Ca-evoked suppression of mitochondrial metabolism. On the other hand, in Ca-supplemented medium, Al partially overcame the inhibitory influence of verapamil. Accordingly, verapamil increased mitochondrial Ca levels much more strongly than Al. However, Al partially reversed the verapamil-evoked rise of Ca²⁺_total level. These data indicate that Al accumulated in cytoplasm in the form of the Al(PO₄)OH⁻ complex may inhibit mitochondrial functions by an increase of intramitochondrial [Ca²⁺]_total resulting from the Al-evoked rise of cytoplasmic [Ca²⁺]_free, as well as from inhibitory interference with the verapamil binding site on the Na⁺/Ca²⁺ antiporter.