Reversibly locking a protein fold in an active conformation with a disulfide bond: Integrin αL I domains with high affinity and antagonist activity in vivo

The integrin αLβ2 has three different domains in its headpiece that have been suggested to either bind ligand or to regulate ligand binding. One of these, the inserted or I domain, has a fold similar to that of small G proteins. The I domain of the αM and α2 subunits has been crystallized in both open and closed conformations; however, the αL I domain has been crystallized in only the closed conformation. We hypothesized that the αL domain also would have an open conformation, and that this would be the ligand binding conformation. Therefore, we introduced pairs of cysteine residues to form disulfides that would lock the αL I domain in either the open or closed conformation. Locking the I domain open resulted in a 9,000-fold increase in affinity to intercellular adhesion molecule-1 (ICAM-1), which was reversed by disulfide reduction. By contrast, the affinity of the locked closed conformer was similar to wild type. Binding completely depended on Mg2+. Orders of affinity were ICAM-1 > ICAM-2 > ICAM-3. The kon, koff, and KD values for the locked open I domain were within 1.5-fold of values previously determined for the αLβ2 complex, showing that the I domain is sufficient for full affinity binding to ICAM-1. The locked open I domain antagonized αLβ2-dependent adhesion in vitro, lymphocyte homing in vivo, and firm adhesion but not rolling on high endothelial venules. The ability to reversibly lock a protein fold in an active conformation with dramatically increased affinity opens vistas in therapeutics and proteomics.

Regulation of the expression of nitric oxide synthase and leishmanicidal activity by glycoconjugates of Leishmania lipophosphoglycan in murine macrophages.

Lipophosphoglycan (LPG) glycoconjugates from promastigotes of Leishmania were not able to induce the expression of the cytokine-inducible nitric oxide synthase (iNOS) by the murine macrophage cell line, J774. However, they synergize with interferon gamma to stimulate the macrophages to express high levels of iNOS. This synergistic effect was critically time-dependent. Preincubation of J774 cells with the LPG glycans 4-18 h before stimulation with interferon gamma resulted in a significant reduction in the expression of iNOS mRNA and of NO synthesis, compared with cells preincubated with culture medium alone. The regulatory effect on the induction of iNOS by LPG is located in the LPG phosphoglycan disaccharide backbone. Synthetic fragments of this backbone had a similar regulatory effect on NO synthesis. Further, the production of NO by activated macrophages in the present system was correlated directly with the leishmanicidal capacity of the cells. These data therefore demonstrate that LPG glycoconjugates have a profound effect on the survival of Leishmania parasites through their ability to regulate the expression of iNOS by macrophages.

Mangrove, Crab and Shorebird Activity as Bioindicators to the Health Status of Mangrove Ecosystems along the Surinamese Coastline, South America

This study focused on the shorebird activity along the Surinamese coast in relation to the mangrove ecosystem health. The health of three estuarine mangrove areas was assessed using important bioindicators of the mangrove ecosystem: crabs, birds and mangroves. Mangrove vegetation was measured at Weg Naar Zee, Matapica canal delta and Coronie coast. Crab activity was measured by burrow and crab counts. Occurring shorebirds were also counted at these areas. The results show that mangrove regeneration and shorebird activity is significantly related to the health of the ecosystem. Weg Naar Zee was the most damaged and highest at risk. Matapica canal delta and the Coronie coast were the least damaged, with Coronie coast showing greatest health and biodiversity of the indicators.

BMI and physical activity in diabetic adolescents followed Hospital Barcelos

Introduction: Physical activity is related to health and lifestyle and should be part of the daily routine of all individuals since it brings many benefits to the body. Ains: To study the adolescent population‘s body mass index (BMI). To study the relation between physical activity and gender. Materials and Methods: We performed a quantitative, observational, analytic and cross-sectional study. After the use of exclusion criteria, a sample of 36 individuals was selected from a population of diabetic adolescents. A validated questionnaire was applied to collected physical activity and personal data. SPSS 22.0 was used to treat the data. The chi-square test was applied to study the relation between the level of physical activity and gender; Fisher’s exact test was applied to study the relation between level of physical activity and BMI. Results and discussion: The chi-square test showed a significant relation between the level of physical activity and gender (p-value = 0.018) with moderate intensity (phi = .4), which corroborates other national and worldwide studies. Fisher’s exact test showed no relation between BMI and the level of physical activity (p-value=0,646). Conclusion: 86,1% of the sampled diabetic adolescents are eutrophic, and 66,7% are considered insufficient active. A significant relation was found between gender and the level of physical activity. No relation was found between BMI and level of physical activity.

Growth, survival, gene expression, microbiota and tryptic activity during feeding of Scophthalmus maximus first feeding larvae with beta-glucan (MacroGard)

Reflecting the natural biology of mass spawning fish aquaculture production of fish larvae is often hampered by high and unpredictable mortality rates. The present study aimed to enhance larval performance and immunity via the oral administration of an immunomodulator, beta-glucan (MacroGard®) in turbot (Scophthalmus maximus). Rotifers (Brachionus plicatilis) were incubated with or without yeast beta-1,3/1,6-glucan in form of MacroGard® at a concentration of 0.5 g/L. Rotifers were fed to first feeding turbot larvae once a day. From day 13 dph onwards all tanks were additionally fed untreated Artemia sp. nauplii (1 nauplius ml/L). Daily mortality was monitored and larvae were sampled at 11 and 24 dph for expression of 30 genes, trypsin activity and size measurements. Along with the feeding of beta-glucan daily mortality was significantly reduced by ca. 15% and an alteration of the larval microbiota was observed. At 11 dph gene expression of trypsin and chymotrypsin was elevated in the MacroGard® fed fish, which resulted in heightened tryptic enzyme activity. No effect on genes encoding antioxidative proteins was observed, whilst the immune response was clearly modulated by beta-glucan. At 11 dph complement component c3 was elevated whilst cytokines, antimicrobial peptides, toll like receptor 3 and heat shock protein 70 were not affected. At the later time point (24 dph) an anti-inflammatory effect in form of a down-regulation of hsp 70, tnf-alpha and il-1beta was observed. We conclude that the administration of beta-glucan induced an immunomodulatory response and could be used as an effective measure to increase survival in rearing of turbot.

The City school-tooth-clinic in Strassburg, Alsace and its activity : presented by the city of Strassburg to the visitors of the exposition ...

Also published in German as Die Städtische Schulzahnklinik in Strassburg im Elsass und ihre Tätigkeit : den Besuchern der Ausstellung überreicht von der Stadt Strassburg.