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1.
Gregory E. Miller Phillip A. Engen Patrick M. Gillevet Maliha Shaikh Masoumeh Sikaroodi Christopher B. Forsyth Ece Mutlu Ali Keshavarzian 《PloS one》2016,11(2)
In the United States, there are persistent and widening socioeconomic gaps in morbidity and mortality from chronic diseases. Although most disparities research focuses on person-level socioeconomic-status, mounting evidence suggest that chronic diseases also pattern by the demographic characteristics of neighborhoods. Yet the biological mechanisms underlying these associations are poorly understood. There is increasing recognition that chronic diseases share common pathogenic features, some of which involve alterations in the composition, diversity, and functioning of the gut microbiota. This study examined whether socioeconomic-status was associated with alpha-diversity of the colonic microbiota. Forty-four healthy adults underwent un-prepped sigmoidoscopy, during which mucosal biopsies and fecal samples were collected. Subjects’ zip codes were geocoded, and census data was used to form a composite indicator of neighborhood socioeconomic-status, reflecting household income, educational attainment, employment status, and home value. In unadjusted analyses, neighborhood socioeconomic-status explained 12–18 percent of the variability in alpha-diversity of colonic microbiota. The direction of these associations was positive, meaning that as neighborhood socioeconomic-status increased, so did alpha-diversity of both the colonic sigmoid mucosa and fecal microbiota. The strength of these associations persisted when models were expanded to include covariates reflecting potential demographic (age, gender, race/ethnicity) and lifestyle (adiposity, alcohol use, smoking) confounds. In these models neighborhood socioeconomic-status continued to explain 11–22 percent of the variability in diversity indicators. Further analyses suggested these patterns reflected socioeconomic variations in evenness, but not richness, of microbial communities residing in the sigmoid. We also found indications that residence in neighborhoods of higher socioeconomic-status was associated with a greater abundance of Bacteroides and a lower abundance of Prevotella, suggesting that diet potentially underlies differences in microbiota composition. These findings suggest the presence of socioeconomic variations in colonic microbiota diversity. Future research should explore whether these variations contribute to disparities in chronic disease outcomes. 相似文献
2.
There has been much recent research interest in the existence of a major axis of life‐history variation along a fast–slow continuum within almost all major taxonomic groups. Eco‐evolutionary models of density‐dependent selection provide a general explanation for such observations of interspecific variation in the "pace of life." One issue, however, is that some large‐bodied long‐lived “slow” species (e.g., trees and large fish) often show an explosive “fast” type of reproduction with many small offspring, and species with “fast” adult life stages can have comparatively “slow” offspring life stages (e.g., mayflies). We attempt to explain such life‐history evolution using the same eco‐evolutionary modeling approach but with two life stages, separating adult reproductive strategies from offspring survival strategies. When the population dynamics in the two life stages are closely linked and affect each other, density‐dependent selection occurs in parallel on both reproduction and survival, producing the usual one‐dimensional fast–slow continuum (e.g., houseflies to blue whales). However, strong density dependence at either the adult reproduction or offspring survival life stage creates quasi‐independent population dynamics, allowing fast‐type reproduction alongside slow‐type survival (e.g., trees and large fish), or the perhaps rarer slow‐type reproduction alongside fast‐type survival (e.g., mayflies—short‐lived adults producing few long‐lived offspring). Therefore, most types of species life histories in nature can potentially be explained via the eco‐evolutionary consequences of density‐dependent selection given the possible separation of demographic effects at different life stages. 相似文献
3.
David Ryberg Toril Tefre Steinar Øvrebø Vidar Skaug Lodve Stangeland Anne Naalsund Rita Bæra Anne-Lise Børresen Aage Haugen 《Human genetics》1990,86(1):40-44
Summary We have examined DNA restriction fragment length polymorphisms (RFLP) of the Ha-ras-1 gene in DNA from 118 lung cancer patients and 123 unaffected controls. When DNA samples were digested with MspI/ HpaII restriction endonucleases. Southern blot analysis demonstrated 4 common, 4 intermediate and 7 different rare alleles in the combined population after hybridization to the pGDa1 probe. Six of the rare alleles were unique for the lung cancer group and 1 rare allele for the control group. The frequency of rare alleles in lung cancer patients (10/236) was significantly different (P<0.01) from the control group (1/246). The lung cancer group also had a significantly lower frequency of the common 2.57 kb fragment than the controls (P<0.02). The results thus indicate that Ha-ras genotyping may be of value in lung cancer risk assessment. 相似文献
4.
Steinar Solberg Tor Larsen Leif Jørgensen 《In vitro cellular & developmental biology. Plant》1985,21(11):612-616
Summary This study examined whether nonconfluent endothelial cell cultures reacted differently than confluent ones toward thrombin-stimulated
platelets or a heparinized salt solution. The adherence to the endothelial cell cultures of51Cr-labeled human platelets stimulated at different thrombin concentrations was studied. There was significantly higher adherence
of stimulated platelets to nonconfluent cultures compared with confluent ones. This was confirmed by scanning electron microscopy,
which also revealed a tendency for the platelets to adhere at the cell periphery. Electron microscopy also showed that thrombin-stimulated
platelets induced endothelial cell contraction. Part of the peripheral endothelial cell surface toward the bottom of the culture
dish was inverted, facing the lumen of the dish. This phenomenon was particularly seen in nonconfluent cultures. When51Cr-labeled endothelial cultures were incubated with a mildly injurious fluid as heparinized sodium acetate and 20% serum,
at 20° C for 30 min, the nonconfluent cultures showed significantly more cell detachment and release of51Cr than the confluent ones. We conclude that under the conditions of the present experiments there are differences in the
reactivity of confluent and nonconfluent endothelial cell cultures. These differences probably reflect biological dissimilarities.
In experiments where properties of cultured endothelium are studied, care should be taken that the degree of confluency is
standardized. 相似文献
5.
Marianna F. Asaroa Andreas Mayr Bart Kahra Donna Van Engen 《Inorganica chimica acta》1994,220(1-2):335-346
Reaction of the allylidene tungsten complex [W(CPhCHCHMe)Br2(CO)2(4-picoline)] (1) with the dithiocarbamates MS2CNR2 (a: M=Na, R=Et; b: M=Na, R=Me; c: M=Li, R=Ph) in THF at 50 °C affords the vinylketene tungsten complexes [W(S2CNR2)2(OCCPhCHCHMe)(CO)] (2a–c). At lower temperatures, four reaction intermediates (3–6) may be discerned. Spectroscopic studies indicate that these compounds contain η4-allyldithiocarbamate ligands which are generated by addition of dithiocarbamate across the metal-carbon double bond of the allylidene-tungsten unit in 1. The structures of [W(S2CNEt2)2(OCCPhCHCHMe)(CO)] (2a) and of one intermediate, [W(η4-Et2NCS2CPhCHCHMe)(S2CNEt2)(CO)2] (5a) were elucidated by X-ray crystallography. 相似文献
6.
The ecology of ruffe,Gymnocephalus cernuus (Pisces: Percidae) introduced to Mildevatn,western Norway 总被引:2,自引:0,他引:2
Steinar Kålås 《Environmental Biology of Fishes》1995,42(3):219-232
Synopsis Diet, habitat use, diel and seasonal activity and a number of population parameters were studied on ruffe,Gymnocephalus cernuus, introduced to Mildevatn, western Norway. This lake is sited outside the natural range of the ruffe and has a lower fish
diversity and a different fish species composition than within its native range. From June through September the ruffe was
planktivorous and mainly caught at 4 to 6 m depth in the benthic zone. At other times of year ruffe was feeding on zoobenthos
and caught deeper in the benthic zone. Ruffe was mainly day active. Zooplankton feeding during summer is the clearest difference
compared to ruffe populations living within its natural range. Presence of large zooplankton organisms available for ruffe
is suggested as the main reason for the difference found in food choice. The availability of large zooplankton is probably
due to community structure caused by a predator and lack of interspecific competition for zooplankton in the deeper parts
of the lake. Piscivorous brown trout.Salmo trutta, restrict the habitat of threespined stickleback,Gasterosteus aculeatus, to the zone of littoral vegetation, allowing high densities of larger zooplankton species likeBythotrephes longimanus to be present in the lake. Brown trout is present only in the upper light and well oxygenated parts of the lake, leaving
a refuge for the ruffe, where they can feed on the rich zooplankton community. 相似文献
7.
I Nafstad E Sannes A Hem P A Engen T Sagvolden 《Journal of Experimental Animal Science》1991,34(3):81-86
Ivermectin (22, 23-dihydroavermectin B 1) in subtoxic doses was administered subcutaneously to young adult DA rats. Prior to treatment the rats had been trained in a visual discrimination learning programme until their response pattern was stable. The behavioural response data were recorded during continued discrimination testing following the Ivermectin injection and compared with those of a control group. The results showed that the Ivermectin injection reduced the total number of lever presses and reinforcement collections. Further the treatment caused an increase in the total number of erroneous responses. 相似文献
8.
Oligotrophication as a result of planktivorous fish removal with rotenone in the small,eutrophic, Lake Mosvatn,Norway 总被引:3,自引:1,他引:2
In September 1987 the shallow, eutrophic, Lake Mosvatn was treated with rotenone to eliminate planktivorous fish (mainly whitefish,Coregonus lavaretus, L.), and the effects were studied. The first summer after treatment the zooplankton community changed markedly from rotifer
dominance and few grazers, to a community with few rotifers and many grazers. Accordingly there was a fivefold increase in
the biomass ofDaphnia galeata. Adult females ofD. galeata approximately doubled in weight. The decrease in rotifer biomass was probably mainly due to a loss of food by competition
with the daphnids. The phytoplankton community was also markedly affected. Prior to treatment Secchi depth was 1.7 m and Chl-a 23μg l−1 in the summer. After treatment there was an increase in the proportion of small and gelatinous algae and the mean chlorophyll
concentration fell to 7μg Chl-a l−1. Secchi depth increased to>2.3 m (bottom-sight most of the season). After the treatment there were also fewer cyanobacterial
blooms. This seems to be related to oligotrophication caused indirectly by increased grazing by the zooplankton. Total nutrient
concentrations were affected. Prior to treatment the mean summer concentration of total phosphate was 44μg P l−1. This decreased to 29μg P l−1 in the first summer and 23μg P l−1 the second summer after the treatment. Total nitrogen decreased from 0.68 mg N l−1 before treatment to 0.32 mg N l−1 the first summer after the treatment. The phosphate loading was not reduced, therefor it can be concluded that the fish removal
provided a biomanipulation which caused the more oligotrophic conditions. 相似文献
9.
10.