| 2. |
- Caswell, J. L., et al.
(author)
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The 6-GHz methanol multibeam maser catalogue - I. Galactic Centre region, longitudes 345° to 6°
- 2010
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In: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY. - 0035-8711. ; 404:2, s. 1029-1060
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Journal article (peer-reviewed)abstract
- We have conducted a Galactic plane survey of methanol masers at 6668 MHz using a seven-beam receiver on the Parkes telescope. Here we present results from the first part, which provides sensitive unbiased coverage of a large region around the Galactic Centre. Details are given for 183 methanol maser sites in the longitude range 345° through the Galactic Centre to 6°. Within 6° of the Galactic Centre, we found 88 maser sites, of which more than half (48) are new discoveries. The masers are confined to a narrow Galactic latitude range, indicative of many sources at the Galactic Centre distance and beyond, and confined to a thin disc population; there is no high-latitude population that might be ascribed to the Galactic bulge. Within 2° of the Galactic Centre the maser velocities all lie between −60 and +77 km s−1, a range much smaller than the 540 km s−1 range observed in CO. Elsewhere, the maser with highest positive velocity (+107 km s−1) occurs, surprisingly, near longitude 355° and is probably attributable to the Galactic bar. The maser with the most negative velocity (−127 km s−1) is near longitude 346°, within the longitude–velocity locus of the near side of the ‘3-kpc arm’. It has the most extreme velocity of a clear population of masers associated with the near and far sides of the 3-kpc arm. Closer to the Galactic Centre the maser space density is generally low, except within 0.25 kpc of the Galactic Centre itself, the ‘Galactic Centre zone’, where it is 50 times higher, which is hinted at by the longitude distribution, and confirmed by the unusual velocities.
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| 3. |
- Png, Chin Wen, et al.
(author)
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Mucolytic bacteria with increased prevalence in IBD mucosa augment in vitro utilization of mucin by other bacteria.
- 2010
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In: The American journal of gastroenterology. - : Ovid Technologies (Wolters Kluwer Health). - 1572-0241 .- 0002-9270. ; 105:11, s. 2420-2428
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Journal article (peer-reviewed)abstract
- OBJECTIVES: Mucosa-associated bacteria are increased in inflammatory bowel disease (IBD), which suggests the possibility of an increased source of digestible endogenous mucus substrate. We hypothesized that mucolytic bacteria are increased in IBD, providing increased substrate to sustain nonmucolytic mucosa-associated bacteria. METHODS: Mucolytic bacteria were characterized by the ability to degrade human secretory mucin (MUC2) in pure and mixed anaerobic cultures. Real-time PCR was used to enumerate mucosa-associated mucolytic bacteria in 46 IBD and 20 control patients. Bacterial mucolytic activity was tested in vitro using purified human MUC2. RESULTS: We confirm increased total mucosa-associated bacteria 16S rRNA gene in macroscopically and histologically normal intestinal epithelium of both Crohn's disease (CD) (mean 1.9-fold) and ulcerative colitis (UC) (mean 1.3-fold). We found a disproportionate increase in some mucolytic bacteria. Mean Ruminococcus gnavus were increased >4-fold and Ruminococcus torques ∼100-fold in macroscopically and histologically normal intestinal epithelium of both CD and UC. The most abundantly detected mucolytic bacterium in controls, Akkermansia muciniphila, was reduced many fold in CD and in UC. Coculture of A. muciniphila with MUC2 as the sole carbon source led to reduction in its abundance while it augmented growth of other bacteria. CONCLUSIONS: Mucolytic bacteria are present in healthy humans, where they are an integral part of the mucosa-associated bacterial consortium. The disproportionate increase in R. gnavus and R. torques could explain increased total mucosa-associated bacteria in IBD.
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