The invasion-associated type III secretion system of Salmonella enterica serovar Typhimurium is necessary for intracellular proliferation and vacuole biogenesis in epithelial cells

Type III secretion systems (TTSS) are used by Gram-negative pathogens to translocate proteins into eukaryotic host cells. Salmonella enterica serovar Typhimurium (S. Typhimurium) has two of these specialized systems, which are encoded on separate Salmonella pathogenicity islands (SPI-1 and SPI-2) and translocate unique sets of effectors. The specific roles of these systems in Salmonella pathogenesis remain undefined, although SPI-1 is required for bacterial invasion of epithelial cells and SPI-2 for survival/replication in phagocytic cells. However, because SPI-1 TTSS mutants are invasion-incompetent, the role of this TTSS in post-invasion processes has not been investigated. In this study, we have used two distinct methods to internalize a non-invasive SPI-1 TTSS mutant (invA) into cultured epithelial cells: (i) co-internalization with wild-type S. Typhimurium (SPI-1-dependent) and (ii) complementation with the Yersinia pseudotuberculosis invasin (inv) gene (SPI-1-independent). In both cases, internalized invA mutants were unable to replicate intracellularly, indicating that SPI-1 effectors are essential for this process and cannot be complemented by wild-type bacteria in the same cell. Analysis of the biogenesis of SCVs showed that vacuoles containing mutant bacteria displayed abnormal maturation that was dependent on the mechanism of entry. Manipulation of Salmonella-containing vacuole (SCV) biogenesis by pharmacologically perturbing membrane trafficking in the host cell increased intracellular replication of wild-type but not mutant S. Typhimurium This demonstrates a previously unknown role for SPI-1 in vacuole biogenesis and intracellular survival in non-phagocytic cells.     

Synthesis and cytotoxic evaluation of novel thiazolocarbazoles. Part III

Novel thiazolocarbazole derivatives have been synthesized via the corresponding imino-1,2,3-dithiazoles. In vitro antitumor activity of these polyheterocyclic compounds was studied.     

Phylogenetic relationships of the Suidae (Mammalia,Cetartiodactyla): new insights on the relationships within Suoidea

Orliac, M. J., Antoine, P. ‐O., Ducrocq, S. (2010). Phylogenetic relationships of the Suidae (Mammalia, Cetartiodactyla): new insights on the relationships within Suoidea. —Zoologica Scripta, 39, 315–330. In most analyses, both molecular and morphological phylogenies of the Cetartiodactyla support the monophyly of Suoidea. However, the evolutionary history of this superfamily remains poorly known primarily due to long‐lasting debates about the taxonomic content and relationships of the suoid families and subfamilies. Despite their crucial position in the reconstruction of the phylogeny of Cetartiodactyla, Suoidea themselves have received little attention in those phylogenies, and no extensive analysis of the group has been performed so far. We therefore examine the phylogeny of the Suidae through the first phylogenetic analysis of Suoidea, including recent and fossil representatives of all four putative families. The results support the monophyly of the traditional suid subfamilies and indicate the Sanitheriidae as sister taxon to the Suidae clade. The evolutionary history within Suidae reveals its complexity, with major convergences involving important morphological structures such as the auditory region or the upper male canine. Divergent signals gathered from either dental or cranio‐mandibular features are responsible for two long‐lasting unresolved issues within Suoidea: the question of the relationships between ‘Old World’ and ‘New World’ peccaries remaining unsolved, as well as the position and familial status of the mid‐Tertiary tayassuid Perchoerus.     

Myocardial Infarct Size and Mortality Depend on the Time of Day—A Large Multicenter Study

Background

Different studies have shown circadian variation of ischemic burden among patients with ST-Elevation Myocardial Infarction (STEMI), but with controversial results. The aim of this study was to analyze circadian variation of myocardial infarction size and in-hospital mortality in a large multicenter registry.

Methods

This retrospective, registry-based study was based on data from AMIS Plus, a large multicenter Swiss registry of patients who suffered myocardial infarction between 1999 and 2013. Peak creatine kinase (CK) was used as a proxy measure for myocardial infarction size. Associations between peak CK, in-hospital mortality, and the time of day at symptom onset were modelled using polynomial-harmonic regression methods.

Results

6,223 STEMI patients were admitted to 82 acute-care hospitals in Switzerland and treated with primary angioplasty within six hours of symptom onset. Only the 24-hour harmonic was significantly associated with peak CK (p = 0.0001). The maximum average peak CK value (2,315 U/L) was for patients with symptom onset at 23:00, whereas the minimum average (2,017 U/L) was for onset at 11:00. The amplitude of variation was 298 U/L. In addition, no correlation was observed between ischemic time and circadian peak CK variation. Of the 6,223 patients, 223 (3.58%) died during index hospitalization. Remarkably, only the 24-hour harmonic was significantly associated with in-hospital mortality. The risk of death from STEMI was highest for patients with symptom onset at 00:00 and lowest for those with onset at 12:00.

Discussion

As a part of this first large study of STEMI patients treated with primary angioplasty in Swiss hospitals, investigations confirmed a circadian pattern to both peak CK and in-hospital mortality which were independent of total ischemic time. Accordingly, this study proposes that symptom onset time be incorporated as a prognosis factor in patients with myocardial infarction.     

A Four-Compartment Metabolomics Analysis of the Liver,Muscle, Serum,and Urine Response to Polytrauma with Hemorrhagic Shock following Carbohydrate Prefeed

Objective

Hemorrhagic shock accompanied by injury represents a major physiologic stress. Fasted animals are often used to study hemorrhagic shock (with injury). A fasted state is not guaranteed in the general human population. The objective of this study was to determine if fed animals would exhibit a different metabolic profile in response to hemorrhagic shock with trauma when compared to fasted animals.

Methods

Proton (1H) NMR spectroscopy was used to determine concentrations of metabolites from four different compartments (liver, muscle, serum, urine) taken at defined time points throughout shock/injury and resuscitation. PLS-DA was performed and VIP lists established for baseline, shock and resuscitation (10 metabolites for each compartment at each time interval) on metabolomics data from surviving animals.

Results

Fed status prior to the occurrence of hemorrhagic shock with injury alters the metabolic course of this trauma and potentially affects mortality. The death rate for CPF animals is higher than FS animals (47 vs 28%). The majority of deaths occur post-resuscitation suggesting reperfusion injury. The metabolomics response to shock reflects priorities evident at baseline. FS animals raise the baseline degree of proteolysis to provide additional amino acids for energy production while CPF animals rely on both glucose and, to a lesser extent, amino acids. During early resuscitation levels of metabolites associated with energy production drop, suggesting diminished demand.

Conclusions

Feeding status prior to the occurrence of hemorrhagic shock with injury alters the metabolic course of this trauma and potentially affects mortality. The response to shock reflects metabolic priorities at baseline.     

Cry Protein Crystals: A Novel Platform for Protein Delivery

Protein delivery platforms are important tools in the development of novel protein therapeutics and biotechnologies. We have developed a new class of protein delivery agent based on sub-micrometer-sized Cry3Aa protein crystals that naturally form within the bacterium Bacillus thuringiensis. We demonstrate that fusion of the cry3Aa gene to that of various reporter proteins allows for the facile production of Cry3Aa fusion protein crystals for use in subsequent applications. These Cry3Aa fusion protein crystals are efficiently taken up and retained by macrophages and other cell lines in vitro, and can be delivered to mice in vivo via multiple modes of administration. Oral delivery of Cry3Aa fusion protein crystals to C57BL/6 mice leads to their uptake by MHC class II cells, including macrophages in the Peyer’s patches, supporting the notion that the Cry3Aa framework can be used to stabilize cargo protein against degradation for delivery to gastrointestinal lymphoid tissues.