The tumour-associated microbiota is an intrinsic component of the tumour microenvironment across human cancer types
. Intratumoral host-microbiota studies have so far largely relied on bulk tissue ...analysis
, which obscures the spatial distribution and localized effect of the microbiota within tumours. Here, by applying in situ spatial-profiling technologies
and single-cell RNA sequencing
to oral squamous cell carcinoma and colorectal cancer, we reveal spatial, cellular and molecular host-microbe interactions. We adapted 10x Visium spatial transcriptomics to determine the identity and in situ location of intratumoral microbial communities within patient tissues. Using GeoMx digital spatial profiling
, we show that bacterial communities populate microniches that are less vascularized, highly immuno‑suppressive and associated with malignant cells with lower levels of Ki-67 as compared to bacteria-negative tumour regions. We developed a single-cell RNA-sequencing method that we name INVADEseq (invasion-adhesion-directed expression sequencing) and, by applying this to patient tumours, identify cell-associated bacteria and the host cells with which they interact, as well as uncovering alterations in transcriptional pathways that are involved in inflammation, metastasis, cell dormancy and DNA repair. Through functional studies, we show that cancer cells that are infected with bacteria invade their surrounding environment as single cells and recruit myeloid cells to bacterial regions. Collectively, our data reveal that the distribution of the microbiota within a tumour is not random; instead, it is highly organized in microniches with immune and epithelial cell functions that promote cancer progression.
ABSTRACT We present ten young ( 10 Myr) late-K and M dwarf stars observed in K2 Campaign 2 that host protoplanetary disks and exhibit quasi-periodic or aperiodic dimming events. Their optical light ...curves show ∼10-20 dips in flux over the 80-day observing campaign with durations of ∼0.5-2 days and depths of up to ∼40%. These stars are all members of the Ophiuchus (∼1 Myr) or Upper Scorpius (∼10 Myr) star-forming regions. To investigate the nature of these "dippers" we obtained: optical and near-infrared spectra to determine stellar properties and identify accretion signatures; adaptive optics imaging to search for close companions that could cause optical variations and/or influence disk evolution; and millimeter-wavelength observations to constrain disk dust and gas masses. The spectra reveal Li i absorption and H emission consistent with stellar youth (<50 Myr), but also accretion rates spanning those of classical and weak-line T Tauri stars. Infrared excesses are consistent with protoplanetary disks extending to within ∼10 stellar radii in most cases; however, the sub-millimeter observations imply disk masses that are an order of magnitude below those of typical protoplanetary disks. We find a positive correlation between dip depth and WISE-2 (Wide-field Infrared Survey Explorer-2) excess, which we interpret as evidence that the dipper phenomenon is related to occulting structures in the inner disk, although this is difficult to reconcile with the weakly accreting aperiodic dippers. We consider three mechanisms to explain the dipper phenomenon: inner disk warps near the co-rotation radius related to accretion; vortices at the inner disk edge produced by the Rossby Wave Instability; and clumps of circumstellar material related to planetesimal formation.
Type VI secretion systems (T6SSs) translocate effectors into target cells and are made of a contractile sheath and a tube docked onto a multi-protein transmembrane complex via a baseplate. Although ...some information is available about the mechanisms of tail contraction leading to effector delivery, the detailed architecture and function of the baseplate remain unknown. Here, we report the 3.7 Å resolution cryo-electron microscopy reconstruction of an enteroaggregative Escherichia coli baseplate subcomplex assembled from TssK, TssF and TssG. The structure reveals two TssK trimers interact with a locally pseudo-3-fold symmetrical complex comprising two copies of TssF and one copy of TssG. TssF and TssG are structurally related to each other and to components of the phage T4 baseplate and of the type IV secretion system, strengthening the evolutionary relationships among these macromolecular machines. These results, together with bacterial two-hybrid assays, provide a structural framework to understand the T6SS baseplate architecture.
Likely transiting exocomets detected by Kepler Rappaport, S.; Vanderburg, A.; Jacobs, T. ...
Monthly Notices of the Royal Astronomical Society,
2018-Feb-21, Letnik:
474, Številka:
2
Journal Article
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Abstract
We present the first good evidence for exocomet transits of a host star in continuum light in data from the Kepler mission. The Kepler star in question, KIC 3542116, is of spectral type F2V ...and is quite bright at Kp = 10. The transits have a distinct asymmetric shape with a steeper ingress and slower egress that can be ascribed to objects with a trailing dust tail passing over the stellar disc. There are three deeper transits with depths of ≃ 0.1 per cent that last for about a day, and three that are several times more shallow and of shorter duration. The transits were found via an exhaustive visual search of the entire Kepler photometric data set, which we describe in some detail. We review the methods we use to validate the Kepler data showing the comet transits, and rule out instrumental artefacts as sources of the signals. We fit the transits with a simple dust-tail model, and find that a transverse comet speed of ∼35–50 km s−1 and a minimum amount of dust present in the tail of ∼1016 g are required to explain the larger transits. For a dust replenishment time of ∼10 d, and a comet lifetime of only ∼300 d, this implies a total cometary mass of ≳3 × 1017 g, or about the mass of Halley's comet. We also discuss the number of comets and orbital geometry that would be necessary to explain the six transits detected over the 4 yr of Kepler prime-field observations. Finally, we also report the discovery of a single comet-shaped transit in KIC 11084727 with very similar transit and host-star properties.
The contribution of the microbiota to disease progression and treatment efficacy is often neglected when determining who is at the highest risk of developing gastrointestinal cancers or designing ...treatment strategies for patients. We reviewed the current literature on the effect of the human microbiota on cancer risk, prognosis, and treatment efficacy. We highlight emerging research that seeks to identify microbial signatures as biomarkers for various gastrointestinal cancers, and discuss how we could harness knowledge of the microbiome to detect, prevent, and treat these cancers. Finally, we outline further research needed in the field of gastrointestinal cancers and the microbiota, and describe the efforts required to increase the accuracy and reproducibility of data linking the microbiome to cancer.
ABSTRACT
BG Ind is a well-studied, bright, nearby binary consisting of a pair of F stars in a 1.46-d orbit. We have discovered in the TESS light curve for TIC 229804573 (aka BG Ind), a second ...eclipsing binary in the system with a 0.53-d period. Our subsequent analyses of the recent TESS and archival ground-based photometric and radial velocity (RV) data reveal that the two binaries are gravitationally bound in a 721-d period, moderately eccentric orbit. We present the results of a joint spectro-photodynamical analysis of the eclipse timing variation curves of both binaries based on TESS and ground-based archival data, the TESS light curve, archival RV data, and the spectral energy distribution, coupled with the use of PARSEC stellar isochrones. We confirm prior studies of BG Ind that found that the brighter binary A consists of slightly evolved F-type stars with refined masses of 1.32 and 1.43 M⊙, and radii of 1.59 and 2.34R⊙. The previously unknown binary B has two less massive stars of 0.69 and 0.64 M⊙ and radii of 0.64 and 0.61R⊙. Based on a number of different arguments that we discuss, we conclude that the three orbital planes are likely aligned to within 17○.
ABSTRACT
In this work we report the discovery and analysis of three new triply eclipsing triple star systems found with the TESS mission during its observations of the northern skies: TICs 193993801, ...388459317, and 52041148. We utilized the TESS precision photometry of the binary eclipses and third-body eclipsing events, ground-based archival and follow-up photometric data, eclipse timing variations, archival spectral energy distributions, as well as theoretical evolution tracks in a joint photodynamical analysis to deduce the system masses and orbital parameters of both the inner and outer orbits. In one case (TIC 193993801) we also obtained radial velocity measurements of all three stars. This enabled us to ‘calibrate’ our analysis approach with and without ‘truth’ (i.e. RV) data. We find that the masses are good to 1–3 per cent accuracy with RV data and 3–10 per cent without the use of RV data. In all three systems we were able to find the outer orbital period before doing any detailed analysis by searching for a longer-term periodicity in the ASAS-SN archival photometry data – just a few thousand ASAS-SN points enabled us to find the outer periods of 49.28 d, 89.86 d, and 177.0 d, respectively. From our full photodynamical analysis we find that all three systems are coplanar to within 1°−3°. The outer eccentricities of the three systems are 0.003, 0.10, and 0.62, respectively (i.e. spanning a factor of 200). The masses of the three stars {Aa, Ab, and B} in the three systems are: {1.31, 1.19, 1.34}, {1.82, 1.73, 2.19}, and {1.62, 1.48, 2.74} M⊙, respectively.
ABSTRACT
In this work, we report the discovery and analysis of six new compact triply eclipsing triple star systems found with the TESS mission: TICs 37743815, 42565581, 54060695, 178010808, ...242132789, and 456194776. All of these exhibit distinct third-body eclipses where the inner eclipsing binary (EB) occults the third (‘tertiary’) star, or vice versa. We utilized the TESS photometry, archival photometric data, and available archival spectral energy distribution curves (SED) to solve for the properties of all three stars, as well as many of the orbital elements. We describe in detail our SED fits, search of the archival data for the outer orbital period, and the final global photodynamical analyses. From these analyses, we find that all six systems are coplanar to within 0°−5°, and are viewed nearly edge on (i.e. within a couple of degrees). The outer orbital periods and eccentricities of the six systems are {Pout (days), e}: {68.7, 0.36}, {123, 0.16}, {60.7, 0.01}, {69.0, 0.29}, {41.5, 0.01}, {93.9, 0.29}, respectively, in the order the sources are listed above. The masses of all 12 EB stars were in the range of 0.7–1.8 M⊙ and were situated near the main sequence. By contrast, the masses and radii of the tertiary stars ranged from 1.5 to 2.3 M⊙ and 2.9 to 12 R⊙, respectively. We use this information to estimate the occurrence rate of compact flat triple systems..
A study of nine compact triply eclipsing triples Rappaport, S A; Borkovits, T; Gagliano, R ...
Monthly Notices of the Royal Astronomical Society,
03/2023, Letnik:
521, Številka:
1
Journal Article
Recenzirano
Odprti dostop
ABSTRACT
In this work, we report the independent discovery and analysis of nine new compact triply eclipsing triple star systems found with the Transiting Exoplanet Survey Satellite (TESS) mission: ...TICs 47151245, 81525800, 99013269, 229785001, 276162169, 280883908, 294803663, 332521671, and 356324779. Each of these nine systems exhibits distinct third-body eclipses where the third (‘tertiary’) star occults the inner eclipsing binary (EB), or vice versa. We utilize a photodynamical analysis of the TESS photometry, archival photometric data, TESS eclipse timing variations of the EBs, available archival spectral energy distribution (SED) curves, and, in some cases, newly acquired radial velocity observations, to solve for the parameters of all three stars, as well as most of the orbital elements. From these analyses we find that the outer orbits of all nine systems are viewed nearly edge on (i.e. within ≲4°), and six of the systems are coplanar to within 5°; the others have mutual inclination angles of 20°, 41°, and possibly 179° (i.e. a retrograde outer orbit). The outer orbital periods range from 47.8 to 604 d, with eccentricities spanning 0.004–0.61. The masses of all 18 EB stars are in the range of 0.9–2.6 M⊙ and are mostly situated near the main sequence. By contrast, the masses and radii of the tertiary stars range from 1.4 to 2.8 M⊙ and 1.5 to 13 R⊙, respectively. We make use of the system parameters from these nine systems, plus those from a comparable number of compact triply eclipsing triples published previously, to gain some statistical insight into their properties.
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