The Balance of Apoptotic and Necrotic Cell Death in Mycobacterium tuberculosis Infected Macrophages Is Not Dependent on Bacterial Virulence

An important mechanism of Mycobacterium tuberculosis pathogenesis is the ability to control cell death pathways in infected macrophages: apoptotic cell death is bactericidal, whereas necrotic cell death may facilitate bacterial dissemination and transmission

The Composition of Comets

This paper is the result of the International Cometary Workshop, held in Toulouse, France in April 2014, where the participants came together to assess our knowledge of comets prior to the ESA Rosetta Mission. In this paper, we look at the composition of the gas and dust from the comae of comets. With the gas, we cover the various taxonomic studies that have broken comets into groups and compare what is seen at all wavelengths. We also discuss what has been learned from mass spectrometers during flybys. A few caveats for our interpretation are discussed. With dust, much of our information comes from flybys. They include {\it in situ} analyses as well as samples returned to Earth for laboratory measurements. Remote sensing IR observations and polarimetry are also discussed. For both gas and dust, we discuss what instruments the Rosetta spacecraft and Philae lander will bring to bear to improve our understanding of comet 67P/Churyumov-Gerasimenko as "ground-truth" for our previous comprehensive studies. Finally, we summarize some of the initial Rosetta Mission findings.Comment: To appear in Space Science Review

Interactions of Attenuated Mycobacterium tuberculosis phoP Mutant with Human Macrophages

Background: Mycobacterium tuberculosis phoP mutant SO2 derived from a clinical isolate was shown to be attenuated in mouse bone marrow-derived macrophages and in vivo mouse infection model and has demonstrated a high potential as attenuated vaccine candidate against tuberculosis. Methodology/Principal Findings: In this study, we analyze the adhesion and the intracellular growth and trafficking of SO2 in human macrophages. Our results indicate an enhanced adhesion to phagocitic cells and impaired intracellular replication of SO2 in both monocyte-derived macrophages and human cell line THP-1 in comparison with the wild type strain, consistent with murine model. Intracellular trafficking analysis in human THP-1 cells suggest that attenuation of SO2 within macrophages could be due to an impaired ability to block phagosome-lysosome fusion compared with the parental M. tuberculosis strain. No differences were found between SO2 and the wild-type strains in the release and mycobacterial susceptibility to nitric oxide (NO) produced by infected macrophages. Conclusions/Significance: SO2 has enhanced ability to bind human macrophages and differs in intracellular trafficking as to wild-type M. tuberculosis. The altered lipid profile expression of the phoP mutant SO2 and its inability to secrete ESAT-6 i

Changes of the phagosomal elemental concentrations by Mycobacterium tuberculosis Mramp

Pathogenic mycobacteria survive within phagosomes which are thought to represent a nutrient-restricted environment. Divalent cation transporters of the Nramp family in phagosomes and mycobacteria (Mramp) may compete for metals that are crucial for bacterial survival. The elemental concentrations in phagosomes of macrophages infected with wild-type Mycobacterium tuberculosis (M. tuberculosis strain H37Rv) and a M. tuberculosis Mramp knockout mutant (Mramp-KO), derived from a clinical isolate isogenic to the strain MT103, were compared. Time points of 1 and 24 h after infection of mouse peritoneal macrophages (bcgS) were compared in both cases. Increased concentrations of P, Ni and Zn and reduced Cl concentration in Mramp-KO after 1 h of infection were observed, compared to M. tuberculosis vacuoles. After 24 h of infection, significant differences in the P, Cl and Zn concentrations were still present. The Mramp-KO phagosome showed a significant increase of P, Ca, Mn, Fe and Zn concentrations between 1 and 24 h after infection, while the concentrations of K and Ni decreased. In the M. tuberculosis vacuole, the Fe concentration showed a similar increase, while the Cl concentration decreased. The fact that the concentration of several divalent cations increased in the Mramp-KO strain suggests that Mramp may have no impact on the import of these divalent cations into the mycobacterium, but may function as a cation efflux pump. The concordant increase of Fe concentrations within M. tuberculosis, as well as within the Mramp-KO vacuoles, implies that Mramp, in contrast to siderophores, might not be important for the attraction of Fe and its retention in phagosomes of unstimulated macrophages

The antibiotic bedaquiline activates host macrophage innate immune resistance to bacterial infection

Antibiotics are widely used in the treatment of bacterial infections. Although known for their microbicidal activity, antibiotics may also interfere with the host's immune system. Here, we analyzed the effects of bedaquiline (BDQ), an inhibitor of the mycobacterial ATP synthase, on human macrophages. Genome-wide gene expression analysis revealed that BDQ reprogramed cells into potent bactericidal phagocytes. We found that 579 and 1,495 genes were respectively differentially expressed in naive- and M. tuberculosis-infected macrophages incubated with the drug, with an over-representation of lysosome-associated genes. BDQ treatment triggered a variety of antimicrobial defense mechanisms, including phagosome-lysosome fusion, and autophagy. These effects were associated with activation of transcription factor EB, involved in the transcription of lysosomal genes, resulting in enhanced intracellular killing of different bacterial species that were naturally insensitive to BDQ. Thus, BDQ could be used as a host-directed therapy against a wide range of bacterial infections

Assessment of the role of transcript for GATA-4 as a marker of unfavorable outcome in human adrenocortical neoplasms

BACKGROUND: Malignant neoplasia of the adrenal cortex is usually associated with very poor prognosis. When adrenocortical neoplasms are diagnosed in the early stages, distinction between carcinoma and adenoma can be very difficult to accomplish, since there is yet no reliable marker to predict tumor recurrence or dissemination. GATA transcription factors play an essential role in the developmental control of cell fate, cell proliferation and differentiation, organ morphogenesis, and tissue-specific gene expression. Normal mouse adrenal cortex expresses GATA-6 while its malignant counterpart only expresses GATA-4. The goal of the present study was to assess whether this reciprocal change in the expression of GATA factors might be relevant for predicting the prognosis of human adrenocortical neoplasms. Since human adrenal cortices express luteinizing hormone (LH/hCG) receptor and the gonadotropins are known to up-regulate GATA-4 in gonadal tumor cell lines, we also studied the expression of LH/hCG receptor. METHODS: We conducted a study on 13 non-metastasizing (NM) and 10 metastasizing/recurrent (MR) tumors obtained from a group of twenty-two adult and pediatric patients. The expression of GATA-4, GATA-6, and LH/hCG receptor (LHR) in normal and tumoral human adrenal cortices was analysed using reverse transcriptase-polymerase chain reaction (RT-PCR) complemented by dot blot hybridization. RESULTS: Messenger RNA for GATA-6 was detected in normal adrenal tissue, as well as in the totality of NM and MR tumors. GATA-4, by its turn, was detected in normal adrenal tissue, in 11 out of 13 NM tumors, and in 9 of the 10 MR tumors, with larger amounts of mRNA found among those presenting aggressive clinical behavior. Transcripts for LH receptor were observed both in normal tissue and neoplasms. A more intense LHR transcript accumulation was observed on those tumors with better clinical outcome. CONCLUSION: Our data suggest that the expression of GATA-6 in human adrenal cortex is not affected by tumorigenesis. GATA-4 expression is more abundant in MR tumors, while NM tumors express more intensely LHR. Further studies with larger cohorts are needed to test whether relative expression levels of LHR or GATA-4 might be used as prognosis predictors

The Evolution of Volatile Production in Comet C-2009 P1(Garradd) During its 2011-2012 Apparition

We report observations at millimeter and submillimeter wavelengths of comet C/2009 P1 (Garradd) from 2011 December 28 to 2012 April 24, using the Arizona Radio Observatory submillimeter telescope (SMT) and the James Clerk Maxwell Telescope (JCMT). Garradd is a dynamically young long-period comet from the Oort Cloud, with a periodicity of 127,000 years, that reached perihelion on 2011 December 23 (at Heliocentric distance (Rh) = 1.55 Astronomical Units and delta = 20.1 Astronomical Units ) and made its closest approach to the Earth on 2012 March 05 (at Heliocentric distance (Rh) = 1.84 Astronomical Units and delta = 1.26 Astronomical Units). We obtained gas production rates, and molecular abundances relative to water for HCN, ortho-H2CO, CS, CO and CH3OH. A rotational temperature, T (sub rot) approximately equal to 50 degrees Kelvin, was determined by observing multiple methanol lines with the JCMT. By averaging the abundance ratio relative to water from the SMT and the JCMT we derive: CO: 7.03 plus or minus 1.84 percent, HCN: 0.04 plus or minus 0.01 percent, ortho H2CO: 0.14 plus or minus 0.03 percent as a parent molecule (and 0.28 plus or minus 0.06 percent as an extended source), CS: 0.03 plus or minus 0.01 percent and CH3OH: 3.11 for a range from plus 1:86 to minus 0.51 percent. We concluded that Garradd is normal in CH3OH, depleted in HCN, ortho-H2CO and CS and slightly enriched in CO with respect to typically observed cometary mixing ratios. We also studied the temporal evolution of HCN and CO and find that the production of HCN has a trend similar to water (but with short-term variation), with a decrease after perihelion, while that of CO shows contrary behavior: remaining constant or increasing after perihelion

Sublimation of icy aggregates in the coma of comet 67P/Churyumov-Gerasimenko detected with the OSIRIS cameras on board Rosetta

Beginning in March 2014, the OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) cameras began capturing images of the nucleus and coma (gas and dust) of comet 67P/Churyumov-Gerasimenko using both the wide angle cam- era (WAC) and the narrow angle camera (NAC). The many observations taken since July of 2014 have been used to study the morphology, location, and temporal variation of the comet’s dust jets. We analyzed the dust monitoring observations shortly after the southern vernal equinox on May 30 and 31, 2015 with the WAC at the heliocentric distance Rh = 1.53 AU, where it is possible to observe that the jet rotates with the nucleus. We found that the decline of brightness as a function of the distance of the jet is much steeper than the background coma, which is a first indication of sublima- tion. We adapted a model of sublimation of icy aggregates and studied the effect as a function of the physical properties of the aggregates (composition and size). The major finding of this article was that through the sublimation of the aggregates of dirty grains (radius a between 5μm and 50μm) we were able to completely reproduce the radial brightness profile of a jet beyond 4 km from the nucleus. To reproduce the data we needed to inject a number of aggregates between 8.5 × 1013 and 8.5 × 1010 for a = 5μm and 50μm respectively, or an initial mass of H2O ice around 22kg

Expression of TNF-alpha-dependent apoptosis-related genes in the peripheral blood of Malagasy subjects with tuberculosis.

The majority of Mycobacterium tuberculosis (Mtb) infections remain asymptomatic with only up to 10% progressing to clinical tuberculosis. However, the constituents of the effective "protective immunity" against tuberculosis responsible for containing most infections remain unknown. Evaluating gene transcriptional profiles in tuberculosis clinical cohorts is one approach to understanding the spectrum of tuberculosis progression. It is clear that apoptosis plays a role in the control of tuberculosis but the utility of apoptosis-related genes as surrogate markers of protection against tuberculosis has not been well investigated. To characterize potential surrogate markers that could discriminate different phases of the clinical tuberculosis spectrum, we investigated gene expression of several TNF-alpha dependent apoptotic genes (TNFR1, TNFR2, FLICE, FLIPs) by real-time RT-PCR of peripheral blood cells from cohorts of individuals with active tuberculosis or potential exposure to tuberculosis. Newly diagnosed tuberculosis patients (n = 23), their close household contacts (n = 80), and community controls (n = 46) were tested at intervals over a period of up to two years. Latent infection or previous Mtb contact was assessed by ELISPOT and TST and complete blood counts were performed during the follow up. Results showed significant upregulation of FLIPs expression by infected individuals regardless of clinical status at entry to the study. A higher percentage of lymphocytes was found in the infected household contacts that remained healthy. In contrast, in individuals with active TB, a significant upregulation of TNFR2 expression, a significantly higher percentage of monocytes and a significantly decreased lymphocyte count were seen, compared to subjects that remained healthy. Moreover, the household contacts who subsequently developed signs of TB also had a significantly high number of monocytes. These data suggest tuberculosis may be associated with decreased T-cell survival (perhaps due to apoptosis) while inhibition of apoptosis in monocytes could lead to a relative increase in these cells: a situation predicted to favour Mtb