The Compatibility of d-Pinitol and 1d-1-O-Methyl-Muco-Inositol with Malate Dehydrogenase Activity

Pinitol (1d -3-O-methyl-chiro-inositol) and 1d -1-O-methyl-muco-inositol, two cyclitols wide-spread in the plant kingdom, were isolated from plant sources in order to test their compatibility with malate dehydrogenase activity. Both compounds had no inhibitory effect on malate dehydrogenase from Rhizophora mangle in a range of 100 to 1000 mol . m^?3. Their influence on malate dehydrogenase activity from different plant sources (Rh. mangle L., Mesembryanthemum crystallinum L., Cicer arietinum L. and Spinacia oleracea L.) was also small and similar to that observed for a number of well established compatible solutes (e.g. proline, glycine betaine). A possible role of cyclitols as cryoprotectants or radical scavengers is discussed.     

Contribution of de novo protein synthesis to the hypertrophic effect of IGF-1 but not of thyroid hormones in adult ventricular cardiomyocytes

Background: Enhanced expression of IGF-1 occurs in left ventricular hypertrophy (LVH) associated with systemic hypertension. Cardiac dysfunction accompanied by LVH is also observed in hyperthyroidism. Objective: to assess the relative contributions of de novo protein synthesis and attenuated protein degradation to increased protein mass associated with cardiomyocyte hypertrophy elicited by IGF-1 and thyroid hormones (tri-iodo thyronine T₃, and l-thyroxine T₄), respectively. Methods: total mass of protein, and both the incorporation, and removal of previously incorporated l-U-¹⁴C-phenylalanine, indices of protein synthesis and degradation, respectively, were assessed in quiescent adult rat ventricular cardiomyocytes maintained in short-term culture, and corrected for DNA content, as a index of cell number. Results: IGF-1 (1 pM-100 nM) increased cell protein significantly, maximally at 1 nM and by 38% above basal value after 24 h. T₃ (10 pM-2 M) and T₄ (10 pM-2 M) increased cell protein significantly maximally at 1 M and by 33.2 and 30.5%, respectively, above basal value. IGF-1 ( 10 pM), T₃ (10 pM-2 M) and T₄ (10 pM-2 M) did not increase incorporation of l-U-₁₄C-phenylalanine above basal values. IGF-1 (100 pM-100 nM) increased incorporation of radiolabel significantly maximally at 100 nM and by 56%. T₄ (100 pM) and IGF-1 (10 pM), concentrations that did not stimulate de novo protein synthesis, attenuated the degradation of radiolabelled protein by 13.6 and 11.8%, respectively, compared to control values after 48 h. Conclusion: These data indicate that the acute hypertrophic response to (i) thyroid hormones cannot be attributed to initiation of de novo protein synthesis; (ii) IGF-1 comprises two components; the response elicited by IGF-1 (< 10 pM) is independent of, while the response elicited by IGF-1 (> 100 pM) is due to de novo protein synthesis.     

Variation of growth form parameters inCapsella (Cruciferae)

Growth form parameters ofCapsella bursa-pastoris populations, including a wide range of different environments, have been analyzed from random block field and growth chamber experiments. Changes in one character are often correlated with changes in another. Of special interest are correlations detected with the onset of first flowering. Variation in each of the characters is clearly influenced by both phenotypic and genotypic components. However, genotype — environment interactions are also subject to variation. Therefore, the adaptive significance of a given parameter is not found to be constant over the entire geographical range of the genus. Alpine populations tend to shift from annual to biannual life cycles.Part of a series Adaptation in life history traits of colonizing plant species. Part of a doctoral thesis by the first author. Dedicated to Prof. Dr.Karl Mägdefrau on the occasion of his 80th birthday.     

Solution structure by nuclear magnetic resonance of the two lantibiotics 97518 and NAI‐107

Lantibiotics 97518 and NAI‐107, produced by the related genera Planomonospora and Microbispora respectively, are members of a family of nisin‐related compounds. They represent promising compounds to treat infections caused by multiresistant Gram‐positive pathogens. Despite their similar structure and a similar antibacterial spectrum, the two lantibiotics exhibit significant differences in their potency. To gain an insight into the structure–activity relationships, their conformational properties in solution are determined by NMR. After carrying out an NOE analysis of 2D ¹H NMR spectra, high‐resolution 3D structures are determined using molecular dynamics simulations. Copyright © 2011 European Peptide Society and John Wiley & Sons, Ltd.     

Life-stage specific environments in a cichlid fish: implications for inducible maternal effects

Through environmentally induced maternal effects females may fine-tune their offspring’s phenotype to the conditions offspring will encounter after birth. If juvenile and adult ecologies differ, the conditions mothers experienced as juveniles may better predict their offspring’s environment than the adult females’ conditions. Maternal effects induced by the environment experienced by females during their early ontogeny should evolve when three ecological conditions are met: (1) Adult ecology does not predict the postnatal environmental conditions of offspring; (2) Environmental conditions for juveniles are correlated across successive generations; and (3) Juveniles occasionally settle in conditions that differ from the juvenile habitat of their mothers. By combining size-structured population counts, ecological surveys and a genetic analysis of population structure we provide evidence that all three conditions hold for Simochromis pleurospilus, a cichlid fish in which mothers adjust offspring quality to their own juvenile ecology. In particular we show (1) that the spatial niches and the habitat quality differ between juveniles and adults, and we provide genetic evidence (2) that usually fish of successive generations grow up in similar habitats, and (3) that occasional dispersal in populations with a different habitat quality is likely to occur. As adults of many species cannot predict their offspring’s environment from ambient cues, life-stage specific maternal effects are likely to be common in animals. It will therefore be necessary to incorporate parental ontogeny in the study of parental effects when juveniles and adults inhabit different environments.     

Molecular genetic study of human arginase deficiency

We have explored the molecular pathology in 28 individuals homozygous or heterozygous for liver arginase deficiency (hyperargininemia) by a combination of Southern analysis, western blotting, DNA sequencing, and PCR. This cohort represents the majority of arginase-deficient individuals worldwide. Only 2 of 15 homozygous patients on whom red blood cells were available had antigenically cross-reacting material as ascertained by western blot analysis using anti-liver arginase antibody. Southern blots of patient genomic DNAs, cut with a variety of restriction enzymes and probed with a near-full-length (1,450-bp) human liver arginase cDNA clone, detected no gross gene deletions. Loss of a TaqI cleavage site was identified in three individuals: in a homozygous state in a Saudi Arabian patient at one site, at a different site in homozygosity in a German patient, and in heterozygosity in a patient from Australia. The changes in the latter two were localized to exon 8, through amplification of this region by PCR and electrophoretic analysis of the amplified fragment after treatment with TaqI; the precise base changes (Arg291X and Thr290Ser) were confirmed by sequencing. It is interesting that the latter nucleotide variant (Thr290Ser) was found to lie adjacent to the TaqI site rather than within it, though whether such a conservative amino acid substitution represents a true pathologic mutation remains to be determined. We conclude that arginase deficiency, though rare, is a heterogeneous disorder at the genotypic level, generally encompassing a variety of point mutations rather than substantial structural gene deletions.