Structural basis for the recognition of complex-type biantennary oligosaccharides by Pterocarpus angolensis lectin

The crystal structure of Pterocarpus angolensis lectin is determined in its ligand-free state, in complex with the fucosylated biantennary complex type decasaccharide NA2F, and in complex with a series of smaller oligosaccharide constituents of NA2F. These results together with thermodynamic binding data indicate that the complete oligosaccharide binding site of the lectin consists of five subsites allowing the specific recognition of the pentasaccharide GlcNAc beta(1-2)Man alpha(1-3)[GlcNAc beta(1-2)Man alpha(1-6)]Man. The mannose on the 1-6 arm occupies the monosaccharide binding site while the GlcNAc residue on this arm occupies a subsite that is almost identical to that of concanavalin A (con A). The core mannose and the GlcNAc beta(1-2)Man moiety on the 1-3 arm on the other hand occupy a series of subsites distinct from those of con A.     

Transfer of dysbiotic gut microbiota has beneficial effects on host liver metabolism

Gut microbiota dysbiosis has been implicated in a variety of systemic disorders, notably metabolic diseases including obesity and impaired liver function, but the underlying mechanisms are uncertain. To investigate this question, we transferred caecal microbiota from either obese or lean mice to antibiotic‐free, conventional wild‐type mice. We found that transferring obese‐mouse gut microbiota to mice on normal chow (NC) acutely reduces markers of hepatic gluconeogenesis with decreased hepatic PEPCK activity, compared to non‐inoculated mice, a phenotypic trait blunted in conventional NOD2 KO mice. Furthermore, transferring of obese‐mouse microbiota changes both the gut microbiota and the microbiome of recipient mice. We also found that transferring obese gut microbiota to NC‐fed mice then fed with a high‐fat diet (HFD) acutely impacts hepatic metabolism and prevents HFD‐increased hepatic gluconeogenesis compared to non‐inoculated mice. Moreover, the recipient mice exhibit reduced hepatic PEPCK and G6Pase activity, fed glycaemia and adiposity. Conversely, transfer of lean‐mouse microbiota does not affect markers of hepatic gluconeogenesis. Our findings provide a new perspective on gut microbiota dysbiosis, potentially useful to better understand the aetiology of metabolic diseases.     

Harmonia axyridis in Great Britain: analysis of the spread and distribution of a non-native coccinellid

Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) is native to Asia, and was widely introduced as a biocontrol agent of aphids and coccids in Europe and North America. In Europe H. axyridis is considered to be an invasive alien species. Although not known to have been deliberately introduced to Great Britain, it was first recorded there in 2004, in south-east England. Harmonia axyridis arrived in Great Britain by various means, primarily from mainland Europe, but also from Canada. Extensive national and local media coverage, and a dedicated website (), facilitated public involvement in recording H. axyridis in Great Britain; in excess of 4,000 verified records of the species were received between 2004 and 2006. Through detailed mapping, the objective of our study was to quantify and analyse the spread of H. axyridis in its early stages of invasion in Great Britain. Our data shows that between 2004 and 2006, the species spread north through Great Britain at the rate of 58 km year^-1 and west at the rate of 144.5 km year^-1. In England H. axyridis spread north to Yorkshire and west to Cornwall by the end of 2006, and also reached Wales. Recorded occurrence (of one or more H. axyridis individuals at larval, pupal and/or adult stage) in 10 km squares in Great Britain was: 2004—51; 2005—149; 2006—447. Records of juvenile H. axyridis extend through most of the recorded British range of the species, and we present evidence of bi-voltinism in the population in 2006.     

Taurine biosynthesis enzyme cysteine sulfinate decarboxylase (CSD) from brain: The long and tricky trail to identification

Conclusion Most of the previous inconsistencies reported in the early works on CSD from brain, can be readily explained by the presence of two CSD activities in a brain extract in vitro. Their respective nature is now fully elucidated. On the one hand, the so-called CSD II activity is indeed a side activity expressed by GAD in vitro that is unlikely to play a physiologically relevant role in the biosynthesis of taurine in vivo. However it must be recalled that it represents the major contribution to the brain CSD total activity when measured in vitro. On the other hand, the so-called CSD I activity appears to be identical to liver CSD according to all biochemical evidence available to date. It is the most likely enzyme involved in taurine biosynthesis in vivo, and accordingly it represents a putative marker of taurine producing cells in the brain. It must be noticed that in the absence of specific inhibitors direct experimental evidence to support this hypothesis is still lacking. Taking into account all the data gathered in this review the CSD I and CSD II designation that referred only to a chromatography elution order has become obsolete and therefore must be henceforth abandoned. CSD II, as an activity expressed by GAD in vitro, must be called GAD associated CSD activity i.e. GAD/CSD., while CSD I as the brain enzyme identical to liver enzyme must be named CSD solely. According to our present immunocytochemical findings, this latter enzyme was not found in the cerebellum in nerve cells but in glial cells. These results provide the cellular basis for a role for taurine in relation to glial function, possibly as a general purpose regulator manufactured and released by glial cells.Special issue dedicated to Dr. Alan N. Davison.     

Time-dependent changes in ghrelin-immunoreactivity in dissociated neuronal cultures of the newborn rat neocortex

Ghrelin is a hormone, initially described as a gastric peptide stimulating appetite and growth hormone secretion, which also has an important role in the regulation of many other processes, including higher brain functions. Ghrelin has been described in situ in different parts of the brain, but so far there has been no data about its expression in cell cultures. Therefore, we aimed in this study to investigate the levels of ghrelin in dissociated cortical neurons at various times in culture. We applied the ABC immunocytochemical method for the detection of ghrelin in one-day-, one-week-, and two-week-old cultures. Our results clearly show that at the early stages after plating the cultures 86.2% (± 8.93) of the neurons are ghrelin-positive and their number decreases during the culturing period. As ghrelin is present in the majority of cultured newborn neurons, when the neuronal differentiation and network formation take place, it may also influence the early synaptic formation and cell-to-cell interactions, which are both very important for network functions like learning and memory.