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"Perrotta, Alison"
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Microbial Reprogramming Inhibits Western Diet-Associated Obesity
A recent epidemiological study showed that eating 'fast food' items such as potato chips increased likelihood of obesity, whereas eating yogurt prevented age-associated weight gain in humans. It was demonstrated previously in animal models of obesity that the immune system plays a critical role in this process. Here we examined human subjects and mouse models consuming Westernized 'fast food' diet, and found CD4(+) T helper (Th)17-biased immunity and changes in microbial communities and abdominal fat with obesity after eating the Western chow. In striking contrast, eating probiotic yogurt together with Western chow inhibited age-associated weight gain. We went on to test whether a bacteria found in yogurt may serve to lessen fat pathology by using purified Lactobacillus reuteri ATCC 6475 in drinking water. Surprisingly, we discovered that oral L. reuteri therapy alone was sufficient to change the pro-inflammatory immune cell profile and prevent abdominal fat pathology and age-associated weight gain in mice regardless of their baseline diet. These beneficial microbe effects were transferable into naïve recipient animals by purified CD4(+) T cells alone. Specifically, bacterial effects depended upon active immune tolerance by induction of Foxp3(+) regulatory T cells (Treg) and interleukin (Il)-10, without significantly changing the gut microbial ecology or reducing ad libitum caloric intake. Our finding that microbial targeting restored CD4(+) T cell balance and yielded significantly leaner animals regardless of their dietary 'fast food' indiscretions suggests population-based approaches for weight management and enhancing public health in industrialized societies.
Journal Article
Microbial Reprogramming Inhibits Western Diet-Associated Obesity. e68596
A recent epidemiological study showed that eating 'fast food' items such as potato chips increased likelihood of obesity, whereas eating yogurt prevented age-associated weight gain in humans. It was demonstrated previously in animal models of obesity that the immune system plays a critical role in this process. Here we examined human subjects and mouse models consuming Westernized 'fast food' diet, and found CD4+ T helper (Th)17-biased immunity and changes in microbial communities and abdominal fat with obesity after eating the Western chow. In striking contrast, eating probiotic yogurt together with Western chow inhibited age-associated weight gain. We went on to test whether a bacteria found in yogurt may serve to lessen fat pathology by using purified Lactobacillus reuteri ATCC 6475 in drinking water. Surprisingly, we discovered that oral L. reuteri therapy alone was sufficient to change the pro-inflammatory immune cell profile and prevent abdominal fat pathology and age-associated weight gain in mice regardless of their baseline diet. These beneficial microbe effects were transferable into naive recipient animals by purified CD4+ T cells alone. Specifically, bacterial effects depended upon active immune tolerance by induction of Foxp3+ regulatory T cells (Treg) and interleukin (Il)-10, without significantly changing the gut microbial ecology or reducing ad libitum caloric intake. Our finding that microbial targeting restored CD4+ T cell balance and yielded significantly leaner animals regardless of their dietary 'fast food' indiscretions suggests population-based approaches for weight management and enhancing public health in industrialized societies.
Journal Article
Microbial Reprogramming Inhibits Western Diet-Associated Obesity
THEOFILOS POUTAHIDIS, MARKUS KLEINEWIETFELD,
CHRISTOPHER SMILLIE, TATIANA LEVKOVICH,
ALISON PERROTTA, SIDDHESHVAR BHELA,
BERNARD J. VARIAN,YASSIN M. IBRAHIM, JESSICA R. LAKRITZ,
SEAN M. KEARNEY, ANTONIS CHATZIGIAGKOS,
DAVID A. HAFLER, ERIC J. ALM MAIL, AND SUSAN E. ERDMAN3.1 INTRODUCTIONThe risk of developing obesity rises with a Westernized lifestyle. In industrialized and developing countries obesity contributes to increased mortality by predisposing to serious pathological conditions such as type 2
diabetes, cardiovascular disease, fatty liver, arthritis, asthma, and neoplasia [1]–[2]. Clinical and experimental data suggest that the white adipose
tissue of obese organisms is in a low-grade, persistent state of chronic inflammation that exerts adverse systemic effects [2]–[3]. The most prominent inflammatory cell type of the obesity-associated inflammation is theadipose tissue macrophage. Macrophages are recruited and surround dead
adipocytes, thus creating the so-called crown-like structures (CLS). These
cells along with hypertrophic adipocytes are thought to be the key cells
initiating the unique subclinical pro-inflammatory signaling cascade encountered in obesity [2], [4]–[5]. Macrophages, B and T lymphocytes, and
up-regulated pro-inflammatory cytokines including TNF-α, IL-1, IL-6,
IL-17, and monocyte chemoattractant protein-1 (MCP-1) have been reported to contribute to obesity-associated pathologies. In parallel, regulatory T cells down-regulate host inflammatory responses [2]–[3], [6]–[10].
Book Chapter
Ionized gas extends over 40 kpc in an odd radio circle host galaxy
A new class of extragalactic astronomical sources discovered in 2021, named odd radio circles (ORCs)
1
, are large rings of faint, diffuse radio continuum emission spanning approximately 1 arcminute on the sky. Galaxies at the centres of several ORCs have photometric redshifts of
z
≃ 0.3–0.6, implying physical scales of several 100 kpc in diameter for the radio emission, the origin of which is unknown. Here we report spectroscopic data on an ORC including strong [O
ii
] emission tracing ionized gas in the central galaxy of ORC4 at
z
= 0.4512. The physical extent of the [O
ii
] emission is approximately 40 kpc in diameter, larger than expected for a typical early-type galaxy
2
but an order of magnitude smaller than the large-scale radio continuum emission. We detect an approximately 200 km s
−1
velocity gradient across the [O
ii
] nebula, as well as a high velocity dispersion of approximately 180 km s
−1
. The [O
ii
] equivalent width (approximately 50 Å) is extremely high for a quiescent galaxy. The morphology, kinematics and strength of the [O
ii
] emission are consistent with the infall of shock ionized gas near the galaxy, following a larger, outward-moving shock. Both the extended optical and radio emission, although observed on very different scales, may therefore result from the same dramatic event.
We find that the optical emission due to ionized gas that is characteristic of a shock extends 40 kpc in diameter across the host galaxy of an odd radio circle.
Journal Article
Understanding the Nature of an Unusual Post-Starburst Quasar with Exceptionally Strong Ne V Emission
We present a \\(z = 0.94\\) quasar, SDSS J004846.45-004611.9, discovered in the SDSS-III BOSS survey. A visual analysis of this spectrum reveals highly broadened and blueshifted narrow emission lines, in particular [Ne~V]\\(\\lambda3426\\) and [O~III]\\(\\lambda5007\\), with outflow velocities of 4000 km s\\(^{-1}\\), along with unusually large [Ne V]\\(\\lambda3426\\)/[Ne III]\\(\\lambda3869\\) ratios. The gas shows higher ionization at higher outflow velocities, indicating a connection between the powerful outflow and the unusual strength of the high ionization lines. The SED and the \\(i - \\text{W3}\\) color of the source reveal that it is likely a \"core\" Extremely Red Quasar (core ERQ); a candidate population of young AGN that are violently \"blowing out\" gas and dust from their centers. The dominance of host galaxy light in its spectrum and its fortuitous position in the SDSS S82 region allows us to measure its star formation history and investigate for variability for the first time in an ERQ. Our analysis indicates that SDSS J004846.45-004611.9 underwent a short-lived starburst phase 400 Myr ago and was subsequently quenched, possibly indicating a time-lag between star formation quenching and the onset of AGN activity. We also find that the strong extinction can be uniquely attributed to the AGN and does not persist in the host galaxy, contradicting a scenario where the source has recently transitioned from being a dusty sub-mm galaxy. In our relatively shallow photometric data, the source does not appear to be variable at \\(0.24-2.4~\\mu\\)m in the restframe, most likely due to the dominant contribution of host galaxy starlight at these wavelengths.
Paper
The Intrinsic Sizes of Odd Radio Circles
A new class of radio source, the so-called Odd Radio Circles (ORCs), have been discovered by recent sensitive, large-area radio continuum surveys. The distances of these sources have so far relied on photometric redshifts of optical galaxies found at the centers of or near the ORCs. Here we present Gemini rest-frame optical spectroscopy of six galaxies at the centers of, or potentially associated with, the first five ORC discoveries. We supplement this with Legacy Survey imaging and Prospector fits to their griz+W1/W2 photometry. Of the three ORCs with central galaxies, all lie at distances (z = 0.27-0.55) that confirm the large intrinsic diameters of the radio circles (300-500 kpc). The central galaxies are massive (\\(M_*\\sim10^{11}M_\\odot\\)), red, unobscured ellipticals with old (\\(\\gtrsim\\)1~Gyr) stellar populations. They have LINER spectral types that are shock- or AGN-powered. All three host low-luminosity, radio-quiet AGN. The similarity of their central galaxies are consistent with a common origin, perhaps as a blastwave from an ancient starburst. The other two ORCs are adjacent and have no prominent central galaxies. However, the z=0.25 disk galaxy that lies between them hosts a Type 2, moderate-luminosity AGN. They may instead be the lobes of a radio jet from this AGN.
Paper
Compact Starburst Galaxies with Fast Outflows: Central Escape Velocities and Stellar Mass Surface Densities from Multi-band Hubble Space Telescope Imaging
We present multi-band Hubble Space Telescope imaging that spans rest-frame near-ultraviolet through near-infrared wavelengths (0.3-1.1 \\(\\mu\\)m) for 12 compact starburst galaxies at z=0.4-0.8. These massive galaxies (M_stellar ~ 10^11 M_Sun) are driving very fast outflows (\\(v_{max}\\)=1000-3000 km/s), and their light profiles are dominated by an extremely compact starburst component (half-light radius ~ 100 pc). Our goal is to constrain the physical mechanisms responsible for launching these fast outflows by measuring the physical conditions within the central kiloparsec. Based on our stellar population analysis, the central component typically contributes \\(\\approx\\)25% of the total stellar mass and the central escape velocities \\(v_{esc,central}\\approx900\\) km/s are a factor of two smaller than the observed outflow velocities. This requires physical mechanisms that can accelerate gas to speeds significantly beyond the central escape velocities, and it makes clear that these fast outflows are capable of traveling into the circumgalactic medium, and potentially beyond. We find central stellar densities comparable to theoretical estimates of the Eddington limit, and we estimate \\(\\Sigma_1\\) surface densities within the central kpc comparable to those of compact massive galaxies at \\(0.5
Paper
Kinematics, Structure, and Mass Outflow Rates of Extreme Starburst Galactic Outflows
We present results on the properties of extreme gas outflows in massive (\\(\\rm M_* \\sim\\)10\\(^{11} \\ \\rm M_{\\odot}\\)), compact, starburst ($\\rm SFR \\sim$$200 \\, \\rm M_{\\odot} \\ yr^{-1}\\() galaxies at z = \\)0.4-0.7\\( with very high star formation surface densities (\\)\\rm \\Sigma_{SFR} \\sim$$2000 \\,\\rm M_{\\odot} \\ yr^{-1} \\ kpc^{-2}\\(). Using optical Keck/HIRES spectroscopy of 14 HizEA starburst galaxies we identify outflows with maximum velocities of \\)820 - 2860\\( \\kmps. High-resolution spectroscopy allows us to measure precise column densities and covering fractions as a function of outflow velocity and characterize the kinematics and structure of the cool gas outflow phase (T \\)\\sim\\(10\\)^4\\( K). We find substantial variation in the absorption profiles, which likely reflects the complex morphology of inhomogeneously-distributed, clumpy gas and the intricacy of the turbulent mixing layers between the cold and hot outflow phases. There is not a straightforward correlation between the bursts in the galaxies' star formation histories and their wind absorption line profiles, as might naively be expected for starburst-driven winds. The lack of strong \\mgii \\ absorption at the systemic velocity is likely an orientation effect, where the observations are down the axis of a blowout. We infer high mass outflow rates of \\)\\rm \\sim\\(50 \\)-\\( 2200 \\)\\rm M_{\\odot} \\, yr^{-1}\\(, assuming a fiducial outflow size of 5 kpc, and mass loading factors of \\)\\eta\\sim\\(5 for most of the sample. %with \\)\\eta\\sim$20 for two galaxies. While these values have high uncertainties, they suggest that starburst galaxies are capable of ejecting very large amounts of cool gas that will substantially impact their future evolution.
Paper
The Ionization and Dynamics of the Makani Galactic Wind
The Makani galaxy hosts the poster child of a galactic wind on scales of the circumgalactic medium. It consists of a two-episode wind in which the slow, outer wind originated 400 Myr ago (Episode I; R_I = 20-50 kpc) and the fast, inner wind is 7 Myr old (Episode II; R_II = 0-20 kpc). While this wind contains ionized, neutral, and molecular gas, the physical state and mass of the most extended phase--the warm, ionized gas--is unknown. Here we present Keck optical spectra of the Makani outflow. These allow us to detect hydrogen lines out to r = 30-40 kpc and thus constrain the mass, momentum, and energy in the wind. Many collisionally-excited lines are detected throughout the wind, and their line ratios are consistent with 200-400 km/s shocks that power the ionized gas, with v_shock = \\(\\sigma\\)_wind. Combining shock models, density-sensitive line ratios, and mass and velocity measurements, we estimate that the ionized mass and outflow rate in the Episode II wind could be as high as that of the molecular gas: M_II(HII) ~ M_II(H_2) = (1-2)x10^9 Msun and dM/dt_II(HII) ~ dM/dt_II(H_2) = 170-250 Msun/yr. The outer wind has slowed, so that dM/dt_I(HII) ~ 10 Msun/yr, but it contains more ionized gas: M_I(HII) = 5x10^9 Msun. The momentum and energy in the recent Episode II wind imply a momentum-driven flow (p ``boost\" ~ 7) driven by the hot ejecta and radiation pressure from the Eddington-limited, compact starburst. Much of the energy and momentum in the older Episode I wind may reside in a hotter phase, or lie further into the CGM.
Paper
KCWI observations of the extended nebulae in Mrk 273
Ultraluminous infrared galaxies (ULIRGs) represent a critical stage in the merger-driven evolution of galaxies when AGN activity is common and AGN feedback is expected. We present high sensitivity and large field of view intergral field spectroscopy of the ULIRG Mrk 273 using new data from the Keck Cosmic Web Imager (KWCI). The KCWI data captures the complex nuclear region and the two extended nebulae in the northeast (NE) and southwest (SW) to \\(\\sim 20\\) kpc scales. Kinematics in the nuclear region show a fast, extended, bipolar outflow in the direction of the previously reported nuclear superbubbles spanning \\(\\sim 5\\) kpc, two to three times greater than the previously reported size. The larger scale extended nebulae on \\(\\sim 20\\) kpc show fairly uniform kinematics with FWHM \\(\\sim 300 ~\\kmps\\) in the SW nebula and FWHM \\(\\sim 120 ~\\kmps\\) in the NE nebula. We detect for the first time high ionization [NeV]3426, [OIII]4363 and HeII4684 emission lines in the extended NE nebula. Emission line ratios in the nuclear region correlate with the kinematic structures, with the bipolar outflow and the less collimated \"outflow regions\" showing distinct line ratio trends. Line ratio diagnostics of high ionization emission lines reveal non-trivial contribution from shock plus precursor ionization in the NE nebula and the nuclear region, mixed with AGN photoionization. These data are highly constraining for models of cool ionized gas existing ~20 kpc from a galactic nucleus.
Paper