Does Land-Use Intensification Decrease Plant Phylogenetic Diversity in Local Grasslands?

Phylogenetic diversity (PD) has been successfully used as a complement to classical measures of biological diversity such as species richness or functional diversity. By considering the phylogenetic history of species, PD broadly summarizes the trait space within a community. This covers amongst others complex physiological or biochemical traits that are often not considered in estimates of functional diversity, but may be important for the understanding of community assembly and the relationship between diversity and ecosystem functions. In this study we analyzed the relationship between PD of plant communities and land-use intensification in 150 local grassland plots in three regions in Germany. Specifically we asked whether PD decreases with land-use intensification and if so, whether the relationship is robust across different regions. Overall, we found that species richness decreased along land-use gradients the results however differed for common and rare species assemblages. PD only weakly decreased with increasing land-use intensity. The strength of the relationship thereby varied among regions and PD metrics used. From our results we suggest that there is no general relationship between PD and land-use intensification probably due to lack of phylogenetic conservatism in land-use sensitive traits. Nevertheless, we suggest that depending on specific regional idiosyncrasies the consideration of PD as a complement to other measures of diversity can be useful.     

Insulin Resistance is Associated with MCP1-Mediated Macrophage Accumulation in Skeletal Muscle in Mice and Humans

Inflammation is now recognized as a major factor contributing to type 2 diabetes (T2D). However, while the mechanisms and consequences associated with white adipose tissue inflammation are well described, very little is known concerning the situation in skeletal muscle. The aim of this study was to investigate, in vitro and in vivo, how skeletal muscle inflammation develops and how in turn it modulates local and systemic insulin sensitivity in different mice models of T2D and in humans, focusing on the role of the chemokine MCP1. Here, we found that skeletal muscle inflammation and macrophage markers are increased and associated with insulin resistance in mice models and humans. In addition, we demonstrated that intra-muscular TNFα expression is exclusively restricted to the population of intramuscular leukocytes and that the chemokine MCP1 was associated with skeletal muscle inflammatory markers in these models. Furthermore, we demonstrated that exposure of C2C12 myotubes to palmitate elevated the production of the chemokine MCP1 and that the muscle-specific overexpression of MCP1 in transgenic mice induced the local recruitment of macrophages and altered local insulin sensitivity. Overall our study demonstrates that skeletal muscle inflammation is clearly increased in the context of T2D in each one of the models we investigated, which is likely consecutive to the lipotoxic environment generated by peripheral insulin resistance, further increasing MCP1 expression in muscle. Consequently, our results suggest that MCP1-mediated skeletal muscle macrophages recruitment plays a role in the etiology of T2D.     

Identification of two new denitrifying strains of Rhodobacter sphaeroides

Abstract Highly specific polyclonal and antibodies against either nitrate, nitrite or nitrous oxide reductases from a photosynthetic denitrifying bacterium Rhodobacter sphaeroides f. sp. denitrificans were used to show the presence of immunologically reactive proteins in strains that Pellerin and Gest had shown to grow in the dark with nitrate as a terminal acceptor [9]. Two strains of this bacterium, namely 81-3 and 2.4.3 synthesized the three denitrifying enzymes and were capable of denitrification. Strains 81-1 and 2.4.1 (neotype) both expressed nitrate reductase activities but nitrite reductase was not detected since these strains did not reduce nitrite. They also did not grow in the dark with nitrate as a terminal acceptor. Each of strains 81-1, 81-3, 2.4.1 and 2.4.3 contain four plasmids. R. sphaeroides f. sp. denitrificans , however, contains only one large 108 kb plasmid, which is distinctly different in size from those detected in the other strains. This indicates that the 108 kb plasmid is not necessarily specific for denitrification.     

Purification of human intrinsic factor using high-performance ion-exchange chromatography as the final step

Human intrinsic factor was purified 1430-fold from gastric juice with a yield of 75% using two steps: labile ligand affinity chromatography and high-performance ion-exchange chromatography. Intrinsic factor precipitated in the presence of specific autoantibodies and 15% sodium sulfate, had an estimated Mr of 59 000 in 5% SDS electrophoresis and could bind to the specific ileal receptor in vitro. Its carbohydrate composition could be related to N-lactosaminic and O-glycosidic chains. High-performance ion-exchange chromatography was a mild, rapid and efficient procedure to separate completely intrinsic factor from haptocorrin (another glycoprotein of gastric juice which binds cobalamin) and from other contaminating proteins.     

Transposon-induced non-motile mutants of Vibrio cholerae

Non-motile mutants of Vibrio cholerae were isolated after transposon insertion mutagenesis with either Tn5 on a plasmid or Tn10ptac mini-kan in bacteriophage lambda. The physical location and number of transposon insertions was determined. Eighteen Tn5 insertion mutants and 11 Tn10ptac mini-kan insertion mutants had single unique insertion sites. The 18 Tn5 insertions were contained within six different EcoRI fragments and the 11 Tn10ptac mini-kan insertions were contained within eight different fragments of V. cholerae chromosomal DNA. These data suggest that multiple genes are involved in motility. Immunoblot analysis of non-motile mutants with antibody to wild-type flagellar core protein indicated that two of the non-motile mutants made flagellar core protein. Three additional mutants reacted weakly with the antibodies. However, these mutants with immunopositive reactions did not produce any structures which resembled flagella by transmission electron microscopy. In addition, none of the other non-motile mutants produced wild-type flagella. However, five mutants which did not react in the immunoblot produced a structure which resembled a flagellar sheath without the internal flagellar core. In addition to having no filamentous core, the sheaths often extended from the sides of the bacteria, rather than from the poles where the flagellum is normally located. The data suggest that sheath formation is independent of flagellar filament formation, but that proper positioning of the sheath may require the flagellar filament.     

Evaluation of biological availability and anti-arrhythmic effect of a new drug Phenytoinum "Polfa"]

Studies were performed in 15 patients with ventricular arrhythmia. During the first day, the patients received 1000 mg of a new micronised form of Phenytoinum "Polfa" or adequate dose of a foreign drug in 3 doses every 3 hours and subsequently during 10 days alternatively native or foreign drug in a daily dose 300 mg. Twenty-four EKG Holter monitoring and determination of serum drug level were carried out after a 10-day treatment; area under the curve (AUC) in one 8 h dose interval was determined. Studies have shown usefulness of a new form of Phenytoinum (Polfa). Blood serum drug levels near to the therapeutic ones were observed. Steady-state Phenytoinum concentration was 11.1 +/- 5.9 micrograms/ml and after foreign drug it was 11.7 +/- 6.1 micrograms/ml, AUC0-8 was 90.4 and 105.3 micrograms/ml/h respectively. In 9/15 patients (60%) Phenytoinum (Polfa) produced substantial improvement in the cardiac arrhythmia.     

Influence of sialic acids on the galactose-recognizing receptor of rat peritoneal macrophages

The interaction of the galactose-recognizing receptor from rat peritoneal macrophages with ligands containing terminal galactose residues, such as asialoorosomucoid, desialylated erythrocytes or lymphocytes, can be inhibited by free N-acetylneuraminic acid (Neu5Ac) and oligosaccharides or glycoproteins containing this sugar in terminal position. This effect of Neu5Ac on the receptor is specific. The other naturally occurring or most of synthetic neuraminic acid derivatives tested do not exhibit an equivalent inhibitory potency as Neu5Ac. Although free Neu5Ac inhibits 5-fold stronger (K50 = 0.2mM) than free galactose, clustering of Neu5Ac in oligosaccharides and glycoproteins does not lead to stronger inhibition, which is in contrast to galactose-containing ligands. A more branched (triantennary) sialooligosaccharide inhibits less than biantennary and unbranched sialooligosaccharides. This may be the reason, why complex sialic acid-containing ligands like native orosomucoid or blood cells are not bound and internalized by the macrophages. The dissociation of asialoorosomucoid from the receptor is slow under the influence of Neu5Ac and requires relatively high concentrations of this sugar, whereas the dissociation mediated by galactose is rapid and requires lower concentrations. An allosteric influence of Neu5Ac on the binding of galactose by the receptor is discussed.     

Characterization of a novel type of chain-terminator Gal beta 1-6Gal beta 1-4)GlcNAc in an oligosaccharide related to N-glycosylated protein glycans isolated from GM1 the urine of patients with gangliosidosis

Two new oligosaccharides were isolated from the urine of a patient with GM1 gangliosidosis. Final purification of the oligosaccharides was accomplished by capillary supercritical fluid chromatography. Structural analysis was by chemical analysis, chemical-ionization mass spectrometry and 400-MHz 1H-NMR spectroscopy, leading to two primary structures. The first is derived from a classical triantennary N-acetyllactosamine-type glycan: Gal beta 1-4GlcNAc beta 1-4(Gal beta 1-4GlcNAc beta 1-2)Man alpha 1-3Man beta 1-4GlcNAc. The second is unusual with a terminal disaccharide Gal beta 1-6Gal, which had not yet been described for glycans of the N-acetyllactosamine type: Gal beta 1-6Gal beta 1-4GlcNAc beta 1-2Man alpha 1-6Man beta 1-4GlcNAc.     

Substrate specificity of rat liver cytosolic alpha-D-mannosidase. Novel degradative pathway for oligomannosidic type glycans.

The substrate specificity of rat liver cytosolic neutral alpha-D-mannosidase was investigated by in vitro incubation with a crude cytosolic fraction of oligomannosyl oligosaccharides Man9GlcNAc, Man7GlcNAc, Man5GlcNAc I and II isomers and Man4GlcNAc having the following structures: Man9GlcNAc, Man(alpha 1-2)Man(alpha 1-3)[Man(alpha 1-2)Man(alpha 1-6)]Man(alpha 1-6) [Man(alpha 1-2)Man(alpha 1-3)]Man(beta 1-4)GlcNAc; Man5GlcNAc I, Man(alpha 1-3)[Man(alpha 1-6)]-Man(alpha 1-6)Man(alpha 1-3)] Man(beta 1-4)GlcNAc; Man5GlcNAc II, Man(alpha 1-2)Man(alpha 1-2)Man(alpha 1-3) [Man(alpha 1-6)]Man(beta 1-4)GlcNAc; Man4GlcNAc, Man(alpha 1-2)Man(alpha 1-2)Man(alpha 1-3)Man(beta 1-4)GlcNAc. The different oligosaccharide isomers resulting from alpha-D-mannosidase hydrolysis were analyzed by 1H-NMR spectroscopy after HPLC separation. The cytosolic alpha-D-mannosidase activity is able to hydrolyse all types of alpha-mannosidic linkages found in the glycans of the oligomannosidic type, i.e. alpha-1,2, alpha-1,3 and alpha-1,6. Nevertheless the enzyme is highly active on branched Man9GlcNAc or Man5GlcNAc I oligosaccharides and rather inactive towards the linear Man4GlcNAc oligosaccharide. Structural analysis of the reaction products of the soluble alpha-D-mannosidase acting on Man5-GlcNAc I and Man9GlcNAc gives Man3GlcNAc, Man(alpha 1-6)[Man(alpha 1-3)]Man(beta 1-4)GlcNAc, and Man5GlcNAc II oligosaccharides, respectively. This Man5GlcNAc II, Man(alpha 1-2)Man(alpha 1-3)[Man(alpha 1-6)]Man(beta 1-4)GlcNAc, represents the 'construction' Man5 oligosaccharide chain of the dolichol pathway formed in the cytosolic compartment during the biosynthesis of N-glycosylprotein glycans. The cytosolic alpha-D-mannosidase is activated by Co2+, insensitive to 1-deoxymannojirimycin but strongly inhibited by swainsonine in the presence of Co2+ ions. The enzyme shows a highly specific action different from that previously described for the lysosomal alpha-D-mannosidases [Michalski, J.C., Haeuw, J.F., Wieruszeski, J.M., Montreuil, J. and Strecker, G. (1990) Eur. J. Biochem. 189, 369-379]. A possible complementarity between cytosolic and lysosomal alpha-D-mannosidase activities in the catabolism of N-glycosylprotein is proposed.     

Combined exposure to hydroelectric expansion,climate change and forest loss jeopardies amphibians in the Brazilian Amazon

Aim

Human‐driven impacts constantly threat amphibians, even in largely protected regions such as the Amazon. The Brazilian Amazon is home to a great diversity of amphibians, several of them currently threatened with extinction. We investigated how climate change, deforestation and establishment of hydroelectric dams could affect the geographic distribution of Amazonian amphibians by 2030 and midcentury.

Location

The Brazilian Amazon.

Methods

We overlapped the geographic distribution of 255 species with the location of hydroelectric dams, models of deforestation and climate change scenarios for the future.

Results

We found that nearly 67% of all species and 54% of species with high degree of endemism within the Legal Brazilian Amazon would lose habitats due to the hydroelectric overlapping. In addition, deforestation is also a potential threat to amphibians, but had a smaller impact compared to the likely changes in climate. The largest potential range loss would be caused by the likely increase in temperature. We found that five amphibian families would have at least half of the species with over 50% of potential distribution range within the Legal Brazilian Amazon limits threatened by climate change between 2030 and 2050.

Main conclusions

Amphibians in the Amazon are highly vulnerable to climate change, which may cause, directly or indirectly, deleterious biological changes for the group. Under modelled scenarios, the Brazilian Government needs to plan for the development of the Amazon prioritizing landscape changes of low environmental impact and economic development to ensure that such changes do not cause major impacts on amphibian species while reducing the emission of greenhouse gases.