Production of taxanes by Taxus baccata plant cells

In callus cultures of Taxus baccata grown on agar media according to Murashige and Skoog supplemented with different growth hormones 8 taxol analogues were identified.     

Duodenal expression of iron transport molecules in patients with hereditary hemochromatosis or iron deficiency

Disturbances of iron metabolism are observed in chronic liver diseases. In the present study, we examined gene expression of duodenal iron transport molecules and hepcidin in patients with hereditary hemochromatosis (HHC) (treated and untreated), involving various genotypes (genotypes which represent risk for HHC were examined), and in patients with iron deficiency anaemia (IDA). Gene expressions of DMT1, ferroportin, Dcytb, hephaestin, HFE and TFR1 were measured in duodenal biopsies using real-time PCR and Western blot. Serum hepcidin levels were measured using ELISA. DMT1, ferroportin and TFR1 mRNA levels were significantly increased in post-phlebotomized hemochromatics relative to controls. mRNAs of all tested molecules were significantly increased in patients with IDA compared to controls. The protein expression of ferroportin was increased in both groups of patients but not significantly. Spearman rank correlations showed that DMT1 versus ferroportin, Dcytb versus hephaestin and DMT1 versus TFR1 mRNAs were positively correlated regardless of the underlying cause, similarly to protein levels of ferroportin versus Dcytb and ferroportin versus hephaestin. Serum ferritin was negatively correlated with DMT1 mRNA in investigated groups of patients, except for HHC group. A decrease of serum hepcidin was observed in IDA patients, but this was not statistically significant. Our data showed that although untreated HHC patients do not have increased mRNA levels of iron transport molecules when compared to normal subjects, the expression is relatively increased in relation to body iron stores. On the other hand, post-phlebotomized HHC patients had increased DMT1 and ferroportin mRNA levels possibly due to stimulated erythropoiesis after phlebotomy.     

Cysteine restriction‐specific effects of sulfur amino acid restriction on lipid metabolism

Decreasing the dietary intake of methionine exerts robust anti‐adiposity effects in rodents but modest effects in humans. Since cysteine can be synthesized from methionine, animal diets are formulated by decreasing methionine and eliminating cysteine. Such diets exert both methionine restriction (MR) and cysteine restriction (CR), that is, sulfur amino acid restriction (SAAR). Contrarily, SAAR diets formulated for human consumption included cysteine, and thus might have exerted only MR. Epidemiological studies positively correlate body adiposity with plasma cysteine but not methionine, suggesting that CR, but not MR, is responsible for the anti‐adiposity effects of SAAR. Whether this is true, and, if so, the underlying mechanisms are unknown. Using methionine‐ and cysteine‐titrated diets, we demonstrate that the anti‐adiposity effects of SAAR are due to CR. Data indicate that CR increases serinogenesis (serine biosynthesis from non‐glucose substrates) by diverting substrates from glyceroneogenesis, which is essential for fatty acid reesterification and triglyceride synthesis. Molecular data suggest that CR depletes hepatic glutathione and induces Nrf2 and its downstream targets Phgdh (the serine biosynthetic enzyme) and Pepck‐M. In mice, the magnitude of SAAR‐induced changes in molecular markers depended on dietary fat concentration (60% fat >10% fat), sex (males > females), and age‐at‐onset (young > adult). Our findings are translationally relevant as we found negative and positive correlations of plasma serine and cysteine, respectively, with triglycerides and metabolic syndrome criteria in a cross‐sectional epidemiological study. Controlled feeding of low‐SAA, high‐polyunsaturated fatty acid diets increased plasma serine in humans. Serinogenesis might be a target for treating hypertriglyceridemia.     

Plant traits and regeneration of urban plant communities after disturbance: Does the bud bank play any role?

Questions: What is the relative role of the bud bank, seed and various species traits in the regeneration of urban plant communities after severe disturbances? Do invasive and exotic species, highly abundant in disturbed communities, regenerate better than native species after disturbance? Methods: Hand tilling was applied to three urban plant communities with and without additional herbicide treatment to exclude regeneration from the bud bank. Plant traits were determined from the literature and databases. Species responses to the treatments were evaluated with RDA analyses in CANOCO. Linear models were applied to identify traits that could predict the responses of species to disturbance. Results: The bud bank played a key role in regeneration in the plots without herbicide. In the plots with herbicide treatment, the seed bank was important in re‐establishing vegetation after disturbance. Exclusion of the bud bank by using herbicide allowed the establishment of small annuals, whereas biennials and perennials were successful in plots where the bud bank was not inhibited by herbicide. Exotic species with a long residence time in the local flora were successful in plots where regeneration from the bud bank was excluded, whereas species with short residence times or that were invasive were suppressed by both types of disturbance. Conclusion: In response to various types of disturbance, species with different regeneration strategies (either seeds or bud bank) were promoted. Exotic species were suppressed primarily by disturbance, which suggests that factors other than just regenerative capability contributed to the high abundance of exotics in urban communities.     

Population dynamics of Phalaris arundinacea L. and Urtica dioica L. in a floodplain during a dry period

The distribution of young and old Phalaris arundinacea and Urtica dioica plants across the Lunice River floodplain (Tebo Biosphere Reserve, South Bohemia, Czech Republic) was studied over a three-year dry period. Plants of both species that germinated in the current year were found on sites disturbed by floods and on emerged pool bottoms. Older P. arundinacea plants were only occasionally found on unshaded sites (pool bottoms, sandy drifts in river bed). U. dioica established itself more often on sites shaded by herbaceous plants or by neighboring shrubs. The long-term survival of U. dioica on wet sites seems uncertain because this species is less tolerant of flooding than P. arundinacea. Thus episodic expansion of U. dioica into unmown parts of the floodplain is expected.This paper was presented at the INTECOL IV International Wetlands Conference in Columbus, Ohio, 1992, as part of a session organized by Prof. S.E. Jørgensen and sponsored by the International Lake Environment Committee.Corresponding Editor: P. Denny     

Mitochondrial pyruvate carrier in Trypanosoma brucei

Pyruvate is a key product of glycolysis that regulates the energy metabolism of cells. In Trypanosoma brucei, the causative agent of sleeping sickness, the fate of pyruvate varies dramatically during the parasite life cycle. In bloodstream forms, pyruvate is mainly excreted, whereas in tsetse fly forms, pyruvate is metabolized in mitochondria yielding additional ATP molecules. The character of the molecular machinery that mediates pyruvate transport across mitochondrial membrane was elusive until the recent discovery of mitochondrial pyruvate carrier (MPC) in yeast and mammals. Here, we characterized pyruvate import into mitochondrion of T. brucei. We identified mpc1 and mpc2 homologs in the T. brucei genome with attributes of MPC protein family and we demonstrated that both proteins are present in the mitochondrial membrane of the parasite. Investigations of mpc1 or mpc2 gene knock‐out cells proved that T. brucei MPC1/2 proteins facilitate mitochondrial pyruvate transport. Interestingly, MPC is expressed not only in procyclic trypanosomes with fully activated mitochondria but also in bloodstream trypanosomes in which most of pyruvate is excreted. Moreover, MPC appears to be essential for bloodstream forms, supporting the recently emerging picture that the functions of mitochondria in bloodstream forms are more diverse than it was originally thought.     

Focal Length Affects Depicted Shape and Perception of Facial Images

Static photographs are currently the most often employed stimuli in research on social perception. The method of photograph acquisition might affect the depicted subject’s facial appearance and thus also the impression of such stimuli. An important factor influencing the resulting photograph is focal length, as different focal lengths produce various levels of image distortion. Here we tested whether different focal lengths (50, 85, 105 mm) affect depicted shape and perception of female and male faces. We collected three portrait photographs of 45 (22 females, 23 males) participants under standardized conditions and camera setting varying only in the focal length. Subsequently, the three photographs from each individual were shown on screen in a randomized order using a 3-alternative forced-choice paradigm. The images were judged for attractiveness, dominance, and femininity/masculinity by 369 raters (193 females, 176 males). Facial width-to-height ratio (fWHR) was measured from each photograph and overall facial shape was analysed employing geometric morphometric methods (GMM). Our results showed that photographs taken with 50 mm focal length were rated as significantly less feminine/masculine, attractive, and dominant compared to the images taken with longer focal lengths. Further, shorter focal lengths produced faces with smaller fWHR. Subsequent GMM revealed focal length significantly affected overall facial shape of the photographed subjects. Thus methodology of photograph acquisition, focal length in this case, can significantly affect results of studies using photographic stimuli perhaps due to different levels of perspective distortion that influence shapes and proportions of morphological traits.