Exo‐ and surface proteomes of the probiotic bacterium Lactobacillus acidophilus NCFM

Lactobacillus acidophilus NCFM is a well‐known probiotic bacterium extensively studied for its beneficial health effects. Exoproteome (proteins exported into culture medium) and surface proteome (proteins attached to S‐layer) of this probiotic were identified by using 2DE followed by MALDI TOF MS to find proteins potentially involved in bacteria–host interactions. The exo‐ and surface proteomes included 43 and 39 different proteins from 72 and 49 successfully identified spots, respectively. Twenty‐two proteins were shared between the two proteomes; both contained the major surface layer protein that participates in host interaction as well as several well‐known and putative moonlighting proteins. The exoproteome contained nine classically‐secreted (containing a signal sequence) and ten nonclassically‐secreted proteins, while the surface proteome contained four classically‐secreted and eight nonclassically secreted proteins. Identification of exo‐ and surface proteomes contributes describing potential protein‐mediated probiotic–host interactions.     

Metabolically Improved Exopolysaccharide Production by Streptococcus thermophilus and Its Influence on the Rheological Properties of Fermented Milk

Altered levels of enzymes in the central carbon metabolism in Streptococcus thermophilus increased the exopolysaccharide (EPS) production 3.3 times over that of the parent strain. The influence of enhanced EPS production on the rheological properties of fermented milk is described for engineered strains of S. thermophilus which produce different levels of EPSs.     

Synthesis of 2'-([1,2,3]triazol-1-yl)-2'-deoxyadenosines

A reliable and efficient protocol for the synthesis of 2 '-([1,2,3]triazol-1-yl)-2 '-deoxyadenosine derivatives from vidarabine is presented. Vidarabine was converted to 2'-azido-2'-deoxy-3',5-O-(tetraisopropyldisiloxane-1,3-diyl)-adenosine. This azide was used as the starting material for the Cu(I)-catalyzed parallel synthesis of 1,2,3-triazoles using a variety of alkynes. The reactions proceeded in good yield and gave almost exclusively the 1,4-disubstituted 1,2,3-triazoles.     

Crystal structures of barley thioredoxin h isoforms HvTrxh1 and HvTrxh2 reveal features involved in protein recognition and possibly in discriminating the isoform specificity

H-type thioredoxins (Trxs) constitute a particularly large Trx sub-group in higher plants. Here, the crystal structures are determined for the two barley Trx h isoforms, HvTrxh1 and HvTrxh2, in the partially radiation-reduced state to resolutions of 1.7 A, and for HvTrxh2 in the oxidized state to 2.0 A. The two Trxs have a sequence identity of 51% and highly similar fold and active-site architecture. Interestingly, the four independent molecules in the crystals of HvTrxh1 form two relatively large and essentially identical protein-protein interfaces. In each interface, a loop segment of one HvTrxh1 molecule is positioned along a shallow hydrophobic groove at the primary nucleophile Cys40 of another HvTrxh1 molecule. The association mode can serve as a model for the target protein recognition by Trx, as it brings the Met82 Cgamma atom (gamma position as a disulfide sulfur) of the bound loop segment in the proximity of the Cys40 thiol. The interaction involves three characteristic backbone-backbone hydrogen bonds in an antiparallel beta-sheet-like arrangement, similar to the arrangement observed in the structure of an engineered, covalently bound complex between Trx and a substrate protein, as reported by Maeda et al. in an earlier paper. The occurrence of an intermolecular salt bridge between Glu80 of the bound loop segment and Arg101 near the hydrophobic groove suggests that charge complementarity plays a role in the specificity of Trx. In HvTrxh2, isoleucine corresponds to this arginine, which emphasizes the potential for specificity differences between the coexisting barley Trx isoforms.     

Patterns of differentiation in a colour polymorphism and in neutral markers reveal rapid genetic changes in natural damselfly populations

The existence and mode of selection operating on heritable adaptive traits can be inferred by comparing population differentiation in neutral genetic variation between populations (often using F(ST) values) with the corresponding estimates for adaptive traits. Such comparisons indicate if selection acts in a diversifying way between populations, in which case differentiation in selected traits is expected to exceed differentiation in neutral markers [F(ST )(selected) > F(ST )(neutral)], or if negative frequency-dependent selection maintains genetic polymorphisms and pulls populations towards a common stable equilibrium [F(ST) (selected) < F(ST) (neutral)]. Here, we compared F(ST) values for putatively neutral data (obtained using amplified fragment length polymorphism) with estimates of differentiation in morph frequencies in the colour-polymorphic damselfly Ischnura elegans. We found that in the first year (2000), population differentiation in morph frequencies was significantly greater than differentiation in neutral loci, while in 2002 (only 2 years and 2 generations later), population differentiation in morph frequencies had decreased to a level significantly lower than differentiation in neutral loci. Genetic drift as an explanation for population differentiation in morph frequencies could thus be rejected in both years. These results indicate that the type and/or strength of selection on morph frequencies in this system can change substantially between years. We suggest that an approach to a common equilibrium morph frequency across all populations, driven by negative frequency-dependent selection, is the cause of these temporal changes. We conclude that inferences about selection obtained by comparing F(ST) values from neutral and adaptive genetic variation are most useful when spatial and temporal data are available from several populations and time points and when such information is combined with other ecological sources of data.     

Grouping horses according to gender—Effects on aggression, spacing and injuries

Many horse owners tend to group horses according to gender, in an attempt to reduce aggressive interactions and the risk of injuries. The aim of our experiment was to test the effects of such gender separation on injuries, social interactions and individual distance in domestic horses. A total of 66 horses were recruited from 4 different farms in Norway and Denmark and divided into six batches. Within each batch, horses were allotted into one mare group, one gelding group and one mixed gender group, with most groups consisting of three or four animals. After 4–6 weeks of acclimatisation, a trained observer recorded all social interactions using direct, continuous observation 1 h in the morning and 1 h in the afternoon for three consecutive days. Recordings of the nearest neighbour of each horse were performed using instantaneous sampling every 10 min. The horses were inspected for injuries before grouping, day 1 after grouping and after 4–6 weeks. No significant effect of gender composition was found on social interactions (P > 0.05), spacing (P > 0.07) or injuries (P > 0.23). Eighty percent of all aggressive interactions recorded were threats, not involving physical contact. Horses with the smallest space allowance showed the highest mean number of aggressive interactions (28.6 ± 6.1 interactions per 6 h) compared to the mean of all the other batches (8.3 ± 1.0 interactions per 6 h). Very few injuries were found and most were superficial. In conclusion, gender composition does not seem to have any effect on aggression level, spacing or injuries. However, the early social experience of horses, management of feeding and space allowance probably represents more important factors for successful group housing of domestic horses.     

Integration of the barley genetic and seed proteome maps for chromosome 1H, 2H, 3H, 5H and 7H

Two-dimensional gel electrophoresis was used to screen spring barley cultivars for differences in seed protein profiles. In parallel, 72 microsatellite (simple sequence repeat (SSR)) markers and 11 malting quality parameters were analysed for each cultivar. Over 60 protein spots displayed cultivar variation, including peroxidases, serpins and proteins with unknown functions. Cultivars were clustered based on the spot variation matrix. Cultivars with superior malting quality grouped together, indicating malting quality to be more closely correlated with seed proteomes than with SSR profiles. Mass spectrometry showed that some spot variations were caused by amino acid differences encoded by single nucleotide polymorphisms (SNPs). Coding SNPs were validated by mass spectrometry, expressed sequence tag and 2D gel data. Coding SNPs can alter function of affected proteins and may thus represent a link between cultivar traits, proteome and genome. Proteome analysis of doubled haploid lines derived from a cross between a malting (Scarlett) and a feed cultivar (Meltan) enabled genetic localisation of protein phenotypes represented by 48 spot variations, involving e.g. peroxidases, serpins, α-amylase/trypsin inhibitors, peroxiredoxin and a small heat shock protein, in relation to markers on the chromosome map. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

The G428A Nonsense Mutation in FUT2 Provides Strong but Not Absolute Protection against Symptomatic GII.4 Norovirus Infection

In November 2004, 116 individuals in an elderly nursing home in El Grao de Castellón, Spain were symptomatically infected with genogroup II.4 (GII.4) norovirus. The global attack rate was 54.2%. Genotyping of 34 symptomatic individuals regarding the FUT2 gene revealed that one patient was, surprisingly, a non-secretor, hence indicating secretor-independent infection. Lewis genotyping revealed that Lewis-positive and negative individuals were susceptible to symptomatic norovirus infection indicating that Lewis status did not predict susceptibility. Saliva based ELISA assays were used to determine binding of the outbreak virus to saliva samples. Saliva from a secretor-negative individual bound the authentic outbreak GII.4 Valencia/2004/Es virus, but did not in contrast to secretor-positive saliva bind VLP of other strains including the GII.4 Dijon strain. Amino acid comparison of antigenic A and B sites located on the external loops of the P2 domain revealed distinct differences between the Valencia/2004/Es and Dijon strains. All three aa in each antigenic site as well as 10/11 recently identified evolutionary hot spots, were unique in the Valencia/2004/Es strain compared to the Dijon strain. To the best of our knowledge, this is the first example of symptomatic GII.4 norovirus infection of a Le^a+b− individual homozygous for the G428A nonsense mutation in FUT2. Taken together, our study provides new insights into the host genetic susceptibility to norovirus infections and evolution of the globally dominating GII.4 viruses.     

Anti-Inflammatory Thalidomide Improves Islet Grafts Survival and Functions in a Xenogenic Environment

Thalidomide possesses both anti-inflammatory and anti-angiogenic properties. This study investigates its potential application in islet transplantation with a xenogenic transplantation model. Transplantation was performed using C57Bl/6 mice and NMRI nu/nu mice as recipients of porcine islets. Moreover, islet graft vasculature and inflammation were investigated to identify the mechanisms of thalidomide action. In the immunocompetent environment of C57Bl/6 mice, a fast graft rejection was observed. The group treated with thalidomide 200 mg/kg BW per day achieved and maintained euglycemia in the complete observation period for 42 days. The treated mice had more functional islet graft mass with less leukocyte infiltration. The pro-inflammatory TNF-α and VEGF content in islet grafted kidneys was significantly lowered by the treatment. By comparison, thalidomide was not effective in improving graft survival in immunocompromised nude mice. It strongly inhibited the VEGF and TNF-α-induced endothelial proliferation of isolated pig islets in a dose dependent manner. The magnitude of thalidomide''s inhibitory effect was nearly identical to the effect of VEGF- receptor 2 inhibitor SU416 and anti-TNF-receptor 1 neutralizing antibody, and was reversed by sphingosine-1-phosphate. In conclusion, the anti-inflammatory effect of thalidomide improved islet graft survival and function in a transplantation model with a maximum immune barrier.     

Contemporary Parallel Diversification,Antipredator Adaptations and Phenotypic Integration in an Aquatic Isopod

It is increasingly being recognized that predation can be a strong diversifying agent promoting ecological divergence. Adaptations against different predatory regimes can emerge over short periods of time and include many different traits. We studied antipredator adaptations in two ecotypes of an isopod (Asellus aquaticus) that have, diverged in parallel in two Swedish lakes over the last two decades. We quantified differences in escape speed, morphology and behavior for isopods from different ecotypes present in these lakes. Isopods from the source habitat (reed) coexist with mainly invertebrate predators. They are more stream-profiled and have higher escape speeds than isopods in the newly colonized stonewort habitat, which has higher density of fish predators. Stonewort isopods also show more cautious behaviors and had higher levels of phenotypic integration between coloration and morphological traits than the reed isopods. Colonization of a novel habitat with a different predation regime has thus strengthened the correlations between pigmentation and morphology and weakened escape performance. The strong signature of parallelism for these phenotypic traits indicates that divergence is likely to be adaptive and is likely to have been driven by differences in predatory regimes. Furthermore, our results indicate that physical performance, behavior and morphology can change rapidly and in concert as new habitats are colonized.