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A community of commensal microbes, known as the intestinal microbiota, resides within the gastrointestinal tract of animals and plays a role in maintenance of host metabolic homeostasis and resistance to pathogen invasion. Enteroendocrine cells, which are relatively rare in the intestinal epithelium, have evolved to sense and respond to these commensal microbes. Specifically, they express G-protein-coupled receptors and functional innate immune signaling pathways that recognize products of microbial metabolism and microbe-associated molecular patterns, respectively. Here we review recent evidence from Drosophila melanogaster that microbial cues recruit antimicrobial, mechanical, and metabolic branches of the enteroendocrine innate immune system and argue that this response may play a role not only in maintaining host metabolic homeostasis but also in intestinal resistance to invasion by bacterial, viral, and parasitic pathogens.

Invertebrates molt, furry mammals shed, and human skin exfoliates. In this issue of Cell Host & Microbe, Zingl et al. describe a virulence mechanism in which the bacterial pathogen Vibrio cholerae jettisons outer membrane proteins and lipids in vesicles as it enters the mammalian intestine.

BACKGROUND: The COVID-19 pandemic could increase violence against children at home. However, collecting empirical data on violence is challenging due to ethical, safety, and data quality concerns. OBJECTIVE: This study estimated the anticipated effect of COVID-19 on violent discipline at home using multivariable predictive regression models. PARTICIPANTS: Children aged 1-14 years and household members from the Multiple Indicator Cluster Surveys (MICS) conducted in Nigeria, Mongolia, and Suriname before the COVID-19 pandemic were included. METHODS: A conceptual model of how the COVID-19 pandemic could affect risk factors for violent discipline was developed. Country specific multivariable linear models were used to estimate the association between selected variables from MICS and a violent discipline score which captured the average combination of violent disciplinary methods used in the home. A review of the literature informed the development of quantitative assumptions about how COVID-19 would impact the selected variables under a "high restrictions" pandemic scenario, approximating conditions expected during a period of intense response measures, and a "lower restrictions" scenario with easing of COVID-19 restrictions but with sustained economic impacts. These assumptions were used to estimate changes in violent discipline scores. RESULTS: Under a "high restrictions" scenario there would be a 35%-46% increase in violent discipline scores in Nigeria, Mongolia and Suriname, and under a "lower restrictions" scenario there would be between a 4%-6% increase in violent discipline scores in these countries. CONCLUSION: Policy makers need to plan for increases in violent discipline during successive waves of lockdowns.

Microbe-derived acetate activates the Drosophila immunodeficiency (IMD) pathway in a subset of enteroendocrine cells (EECs) of the anterior midgut. In these cells, the IMD pathway co-regulates expression of antimicrobial and enteroendocrine peptides including tachykinin, a repressor of intestinal lipid synthesis. To determine whether acetate acts on a cell surface pattern recognition receptor or an intracellular target, we asked whether acetate import was essential for IMD signaling. Mutagenesis and RNA interference revealed that the putative monocarboxylic acid transporter Tarag was essential for enhancement of IMD signaling by dietary acetate. Interference with histone deacetylation in EECs augmented transcription of genes regulated by the steroid hormone ecdysone including IMD targets. Reduced expression of the histone acetyltransferase Tip60 decreased IMD signaling and blocked rescue by dietary acetate and other sources of intracellular acetyl-CoA. Thus, microbe-derived acetate induces chromatin remodeling within enteroendocrine cells, co-regulating host metabolism and intestinal innate immunity via a Tip60-steroid hormone axis that is conserved in mammals.

Halogenated organic compounds (organohalides) are globally prevalent, recalcitrant toxic, and carcinogenic environmental pollutants. Select microorganisms encode enzymes known as reductive dehalogenases (EC 1.97.1.8) that catalyze reductive dehalogenation reactions resulting in the generation of lesser-halogenated compounds that may be less toxic and more biodegradable. Recent breakthroughs in enzyme structure determination, elucidation of the mechanisms of reductive dehalogenation, and in heterologous expression of functional reductive dehalogenase enzymes have substantially increased our understanding of this fascinating class of enzymes. This knowledge has created opportunities for more versatile (in situ and ex situ) biologically-mediated organohalide destruction strategies.

Dust concentration, wind speed and visibility, measured at four sites in the Gobi Desert and at a site in the steppe zone of Mongolia over a period of 4.5 years (January 2009 to May 2013), have been analyzed for their relationships, their effects on visibility, and for an estimate of the threshold wind necessary for dust emission in the region. Based on quantitative analysis on measurements, we evaluated that dust emission concentrations of 41–61 (20–24) μg m −3 of PM 10 (PM 2.5 ) are as the criterion between normal and hazy atmospheric conditions. With the arrival of dust events, wind-borne soil particulate matter (PM 10 , PM 2.5 ) that originates in the Gobi Desert is changed dramatically. PM 10 (PM 2.5 ) concentrations increase by at least double or by several tens of times during severe dust events in comparison with the normal atmospheric condition. Ratio (PM 2.5 /PM 10 ) between monthly means of PM 10 and PM 2.5 concentrations showed that anthropogenic particles were dominant in the ambient air of province centers in cool months (November to February). Threshold values of the onset of dust events were determined for PM 10 (PM 2.5 ) concentrations. According to the definition of dust storms, dust concentrations of PM 10 corresponding to visibility of 1 km or less were determined at sites in the Gobi Desert and the steppe region. The threshold wind speeds during days with dust events were estimated at four sites in the Gobi Desert and compared each other. The threshold wind was higher at Sainshand and its cause might be due to smaller silt and clay fractions of soil.

Polarization-sensitive Mie-scattering lidars were installed for dust storm monitoring at Sainshand and Zamyn-Uud in the Gobi Desert and at the Mongolian capital city of Ulaanbaatar in 2007. We studied the temporal and spatial distributions and transportation of dust, elevated dust, biomass burning smoke, and anthropogenic aerosol by using lidar measurements from the end of 2007 to the first half of 2010. The study results show that the maximum height of dust layers over the Gobi Desert of Mongolia during dust event periods varied from 0.5 to 5.5 km above the ground level (AGL). The 95th percentile level of dust vertical distribution was found at 4 and 4.5 km for Zamyn-Uud and Sainshand, respectively. The averaged maximum height of dust layers during dust events was 2.0–2.2 km AGL at those Gobi sites. The lidar measurements also revealed transport of dust layers elevated in the atmosphere. Base heights of elevated dust layers varied from 0.5 to 2.5 km AGL, while maximum heights from 2.5 to 4.5 km AGL. Backward air trajectory analyses suggested source areas of the elevated dust that transported from other source regions to southeastern Mongolia. A detail study was conducted of the dust event in 19–20 May 2008. Hourly maximum dust concentrations of PM10 (PM2.5) reached 1139–1409 (384–404) μg m−3 during the dust event episode. Dust concentration of PM10 had high correlations with visibilities. Threshold winds for dust emission were determined at Sainshand and Zamyn-Uud. The lidar measurements at the three sites detected vertical profiles of biomass burning smoke and anthropogenic aerosol with top heights of 3–4 km AGL.

Atmospheric pollution caused by airborne particulate matter in the winter season in Ulaanbaatar, Mongolia is a very serious problem. However, there is a complete lack of scientific observation data to define the situation prior to any remediation. PM10 and PM2.5 average monthly values obtained by continuous monitoring showed the concentrations of particles of both size categories exceeded 100 μg m −3 during November to February (winter). PM10 particles were sampled with filters in January (i.e. during the heating period) and June (i.e.non-heating period) of 2008 in central Ulaanbaatar. To determine the composition of urban airborne particulate matter we analyzed a range of ionic components, multiple elements including heavy metals, and organic and inorganic carbon (soot). We also measured the stable carbon isotope ratio of the soot. Total carbon (sum of organic carbon and inorganic carbon) accounted for 47% of the mass of the PM10 during the heating period and 33% during the non-heating period, and was the largest component of urban airborne particulate matter in Ulaanbaatar. Stable isotope ratios (δ 13 C) of soot generated during the heating period (−23.4 ± 0.2‰) approximated the ratios for coal used in Ulaanbaatar (−21.3 to −24.4‰), while the ratios during the non-heating period (−27.1 ± 0.4‰) were clearly different from the coal values. In the heating period, a very high correlation was observed between soot and organic carbon, SO 4 2– , NO 3 − , F − , Zn, As, and Pb, and we concluded that they were derived from coal combustion along with soot. In addition, the concentrations and their ratios relative to each other of Al, Fe, Ca, K, Na, Mg, and Mn hardly differed between the heating period and the non-heating period, and it was concluded that they were derived from soil dust.

Dust mass concentrations of PM 10 and PM 2.5 from four monitoring stations in the Gobi Desert region of Mongolia were analyzed for a 16-month period in 2009–2010. Annual averaged PM 10 concentration ranged from 9 μg m − 3 to 49 μg m − 3 at these stations during 2009. Concentrations were high in winter owing to air pollution and in spring owing to dust storms; the monthly mean concentrations of PM 10 (PM 2.5 ) at the three stations except for Sainshand reached yearly maxima in December and January, ranging from 60 (38) μg m − 3 to 120 (94) μg m − 3 . Diurnal variations of PM 10 and PM 2.5 concentrations at two sites, Dalanzadgad and Zamyn-Uud, included two maxima in the morning and evening and two minima in the afternoon and early morning. However, at Erdene PM 10 maxima occurred in the afternoon and evening. Both PM 10 and PM 2.5 concentrations were enhanced from March to May by dust storms. Dust storms raised huge amounts of fine dust particles in the Gobi of Mongolia. Maximum daily mean PM 10 (PM 2.5 ) concentrations reached 821 (500) μg m − 3 at Dalanzadgad, 308 (129) μg m − 3 at Zamyn-Uud, and 1328 μg m − 3 at Erdene. Hourly maximum PM 10 (PM 2.5 ) concentrations were as high as 6626 (2899) μg m − 3 at Dalanzadgad during a dust storm.

Continuous monitoring of sand and duststorms (SD) and associated heavy dustfall (HD) is made in Korea. In particular, accurate measurements of atmospheric dust loadings have been carried out with the tapered element oscillating microbalance method, and satellite detection of dust clouds is included in the analysis. In 2002, we found three gigantic dust clouds that moved over the Korean Peninsula, and associated HD occurred with PM10 values of 1106–3006 μg m−3. In Beijing, China much higher concentrations were recorded, while in SW Japan measured values were up to 986 μg m−3. Two SD occurred in March and April, while the third one occurred unusually in November. During the year, there were nine cases of reddish-brown sand with 18 dusty days. The intensity of HD was extraordinary for the recent decade. It was observed that with invading SD, the higher the PM10 values the lower the PM2.5 loadings. Also, variations of visibility were more depending on PM2.5 variations than PM10 values. It is shown that satellite detection is a useful technique in monitoring SD and HD.

Climatology of dust storms in Mongolia is compiled based on observational data of 49 meteorological stations from 1960 to 1999 and compared them with data between 1937 and 1989. Three different maps of the distribution of dust storms, driftingdust and the number of dusty days are presented. The results of the analysis show that the number of days with dust storms is o5 days over the Altai, the Khangai and the Khentei mountainous regions and more than 20– 37 days in the Gobi Desert and semi-desert area. The greatest occurrence of drifting dust arises around the Mongol Els area of west Mongolia. The number of dusty days, which is derived from the sum of the number of days with dust storms and driftingdust, is o10 days in the mountainous area and 61–127 days in the Gobi Desert and the Great Lakes hollow of west Mongolia. It is found that 61% of dust storms occur in the spring in Mongolia and a dust storm lasts on average from 3.1 to 6.0 h. About 65.5–91.0% of dust storms occur in daytime and 9.0–34.5% at night. Dust storms occur more frequently in the city region and are accompanied by surface wind speeds usually from 6 to 20 ms 1 . Dust storms usually occur when soil and air are dry, and 70% of dust storms occur in dry soil conditions. When dust storms occur, relative humidity averages 20–40% in Mongolia. An important outcome of this study is the trend of dusty days between 1960 and 1999. It shows that the number of dusty days has tripled from the 1960s to 1990s and has decreased since 1990. r 2003 Elsevier Science Ltd. All rights reserved.