GSDMD membrane pore formation constitutes the mechanism of pyroptotic cell death

Pyroptosis is a lytic type of cell death that is initiated by inflammatory caspases. These caspases are activated within multi‐protein inflammasome complexes that assemble in response to pathogens and endogenous danger signals. Pyroptotic cell death has been proposed to proceed via the formation of a plasma membrane pore, but the underlying molecular mechanism has remained unclear. Recently, gasdermin D (GSDMD), a member of the ill‐characterized gasdermin protein family, was identified as a caspase substrate and an essential mediator of pyroptosis. GSDMD is thus a candidate for pyroptotic pore formation. Here, we characterize GSDMD function in live cells and in vitro. We show that the N‐terminal fragment of caspase‐1‐cleaved GSDMD rapidly targets the membrane fraction of macrophages and that it induces the formation of a plasma membrane pore. In vitro, the N‐terminal fragment of caspase‐1‐cleaved recombinant GSDMD tightly binds liposomes and forms large permeability pores. Visualization of liposome‐inserted GSDMD at nanometer resolution by cryo‐electron and atomic force microscopy shows circular pores with variable ring diameters around 20 nm. Overall, these data demonstrate that GSDMD is the direct and final executor of pyroptotic cell death.     

Evidence for diabetes-induced alterations in the sulfation of heparin sulfate intestinal epithelial cells

Two compounds with high affinity for the "peripheral type" benzodiazepine binding sites, PK 11195 (an isoquinoline derivative) and RO5-4864 (a benzodiazepine derivative) can modify the sensitivity of DBA/2J mice to audiogenic seizures. RO5-4864 (1-15 mg/kg) facilitates in a dose-dependent manner the audiogenic seizures and PK 11195 (2-5 mg/kg) antagonizes the RO5-4864 effects. At these doses PK 11195 alone does not modify the sensitivity to audiogenic seizures, but at doses between 20-80 mg/kg it protects DBA/2J mice against audiogenic seizures. By contrast PK 11195 is inactive against the facilitation of audiogenic seizures by ethyl-beta-carboline-3-carboxylate (a brain benzodiazepine receptor inverse agonist) and against the seizure elicited in absence of noise stimuli by RO5-4864 at doses between 20-40 mg/kg. These results suggest that facilitation by RO5-4864 of the audiogenic seizures and its antagonism by PK 11195 are mediated by the peripheral type benzodiazepine binding sites and agree with the thermodynamic analysis of the binding data which suggested that RO5-4864 might be an agonist and PK 11195 an antagonist. The good correlation between pharmacological effects and the occupancy degree of the binding sites as measured by the displacement of the "in vivo" [3H]-PK 11195 binding give an additional support to binding sites mediated effects.     

Assessment of Point-of-Care Diagnostics for G6PD Deficiency in Malaria Endemic Rural Eastern Indonesia

Background

Patients infected by Plasmodium vivax or Plasmodium ovale suffer repeated clinical attacks without primaquine therapy against latent stages in liver. Primaquine causes seriously threatening acute hemolytic anemia in patients having inherited glucose-6-phosphate dehydrogenase (G6PD) deficiency. Access to safe primaquine therapy hinges upon the ability to confirm G6PD normal status. CareStart G6PD, a qualitative G6PD rapid diagnostic test (G6PD RDT) intended for use at point-of-care in impoverished rural settings where most malaria patients live, was evaluated.

Methodology/Principal Findings

This device and the standard qualitative fluorescent spot test (FST) were each compared against the quantitative spectrophotometric assay for G6PD activity as the diagnostic gold standard. The assessment occurred at meso-endemic Panenggo Ede in western Sumba Island in eastern Indonesia, where 610 residents provided venous blood. The G6PD RDT and FST qualitative assessments were performed in the field, whereas the quantitative assay was performed in a research laboratory at Jakarta. The median G6PD activity ≥5 U/gHb was 9.7 U/gHb and was considered 100% of normal activity. The prevalence of G6PD deficiency by quantitative assessment (<5 U/gHb) was 7.2%. Applying 30% of normal G6PD activity as the cut-off for qualitative testing, the sensitivity, specificity, positive predictive value, and negative predictive value for G6PD RDT versus FST among males were as follows: 100%, 98.7%, 89%, and 100% versus 91.7%, 92%, 55%, and 99%; P = 0.49, 0.001, 0.004, and 0.24, respectively. These values among females were: 83%, 92.7%, 17%, and 99.7% versus 100%, 92%, 18%, and 100%; P = 1.0, 0.89, 1.0 and 1.0, respectively.

Conclusions/Significance

The overall performance of G6PD RDT, especially 100% negative predictive value, demonstrates suitable safety for G6PD screening prior to administering hemolytic drugs like primaquine and many others. Relatively poor diagnostic performance among females due to mosaic G6PD phenotype is an inherent limitation of any current practical screening methodology.     

Vergleichende Untersuchungen von Pollenkörnern einiger Liliaceen und Amaryllidaceen

Ohne ZusammenfassungDiese Arbeit wurde im Botanisehen Institut der Universität Wien (Direktor: Prof. Dr.Fritz Knoll) im Jahre 1935 durchgefiihrt. Meinem hochverehrten Lehrer, Herrn Prof. Dr.Karl Schnarf, danke ich herzlich für die Anregung zu dieser Arbeit und für das große Interesse an ihrem Werden.     

First histopathological and immunophenotypic analysis of early dynamic events in a patient with segmental vitiligo associated with halo nevi

Segmental vitiligo is often ascribed to the neurogenic theory of melanocyte destruction, although data about the initial etiopathological events are scarce. Clinical, histopathological and T-cell phenotypic analyses were performed during the early onset of a segmental vitiligo lesion in a patient with associated halo nevi. Histopathological analysis revealed a lymphocytic infiltrate, mainly composed of CD8⁺ T-cells and some CD4⁺ T-cells around the dermo–epidermal junction. Flow cytometry analysis of resident T-cells revealed a clear enrichment of pro-inflammatory IFN-γ producing CD8⁺ T-cells in lesional skin compared to the non-lesional skin. Using human leukocyte antigen-peptide tetramers (MART-1, tyrosinase, gp100), increased numbers of T cells, recognizing melanocyte antigens were found in segmental vitiligo lesional skin, as compared with the non-lesional skin and the blood. Our findings indicate that a CD8⁺ melanocyte specific T cell-mediated immune response, as observed in generalized vitiligo, also plays a role in segmental vitiligo with associated halo nevi.     

Effects of an organophosphorous pesticide, dichlorvos, on germ cells of the undifferentiated gonads of young quail embryos

In quail embryos, issued from eggs injected, before incubation, with oil solution of DDVP, the germ population was strongly reducted. However, at the 24 stage of embryonic development, the germ deficit is lower than at older stage (29). This deficit may be due to an inhibition of their gonadic colonizing capacity and an excessive rate of cell death.     

Physiological studies on nitrogen fixation in the blue-green alga anabaena cylindrica

Summary Short-term manometric experiments with bacteria-free cultures of Anabaena cylindrica showed that the close dependency of nitrogen fixation upon photosynthesis could be temporarily eliminated in nitrogen-starved cells. Initial rates of nitrogen uptake by these cells in the absence of carbon dioxide were equally rapid in the light and dark, decreasing and finally ceasing after two hours. Continued steady nitrogen uptake was only maintained for long periods in the presence of carbon dioxide in the light. In the dark, nitrogen uptake was accompanied by carbon dioxide evolution.More oxygen was evolved in the light by cells fixing nitrogen than by those incubated under argon. This additional oxygen evolution could be accounted for by extra carbon dioxide fixation in the presence of nitrogen.Of a number of organic compounds tested, only sodium pyruvate stimulated nitrogen fixation. This stimulation was achieved both in the light and dark and in the presence and absence of carbon dioxide, showing that the role of pyruvate was other than acting as a carbon skeleton.Three metabolic inhibitors, cyanide and chlorpromazine (chiefly respiratory) and phenylurethane (photosynthetic) differentially inhibited photosynthesis and nitrogen fixation. The latter inhibitor had a more marked effect on photosynthesis while the two chiefly respiratory inhibitors had a stronger effect on nitrogen fixation.     

A spatially explicit data-driven approach to assess the effect of agricultural land occupation on species groups

Purpose

Change of vegetation cover and increased land use intensity, particularly for agricultural use, can affect species richness. Within life cycle impact assessment, methods to assess impacts of land use on a global scale are still in need of development. In this work, we present a spatially explicit data-driven approach to characterize the effect of agricultural land occupation on different species groups.

Methods

We derived characterization factors for the direct impact of agricultural land occupation on relative species richness. Our method identifies potential differences in impacts for cultivation of different crop types, on different species groups, and in different world regions. Using empirical species richness data gathered via an extensive literature search, characterization factors were calculated for four crop groups (oil palm, low crops, Pooideae, and Panicoideae), four species groups (arthropods, birds, mammals, and vascular plants), and six biomes.

Results and discussion

Analysis of the collected data showed that vascular plant richness is more sensitive than the species richness of arthropods to agricultural land occupation. Regarding the differences between world regions, the impact of agricultural land use was lower in boreal forests/taiga than in temperate and tropical regions. The impact of oil palm plantations was found to be larger than that of Pooideae croplands, although we cannot rule out that this difference is influenced by the spatial difference between the oil palm- and Pooideae-growing regions as well. Analysis of a subset of data showed that the impact of conventional farming was larger than the impact of low-input farming.

Conclusions

The impact of land occupation on relative species richness depends on the taxonomic groups considered, the climatic region, and farm management. The influence of crop type, however, was found to be of less importance.