120 research outputs found
New 14C Determinations from Lake Suigetsu, Japan:12,000 to 0 Cal BP
Calibration is a fundamental stage of the radiocarbon (14C) dating process if one is to derive meaningful calendar ages from samplesâ 14C measurements. For the first time, the IntCal09 calibration curve (Reimer et al. 2009) provided an internationally ratified calibration data set across almost the complete range (0 to 50,000 cal BP) of the 14C timescale. However, only the last 12,550 cal yr of this record are composed of terrestrial data, leaving approximately three quarters of the 14C timescale necessarily calibrated via less secure, marine records (incorporating assumptions pertaining to the temporally variable âmarine reservoir effectâ). The predominantly annually laminated (varved) sediment profile of Lake Suigetsu, central Japan, offers an ideal opportunity to derive an extended terrestrial record of atmospheric 14C across the entire range of the method, through pairing of 14C measurements of terrestrial plant macrofossil samples (extracted from the sediment) with the independent chronology provided through counting of its annual laminations.
This paper presents new data (182 14C determinations) from the upper (largely non-varved) 15 m of the Lake Suigetsu (SG06) sediment strata. These measurements provide evidence of excellent coherence between the Suigetsu 14C data and the IntCal09 calibration curve across the last ~12,000 cal yr (i.e. the portion of IntCal based entirely on terrestrial data). Such agreement demonstrates that terrestrial plant material picked from the Lake Suigetsu sediment provides a reliable archive of atmospheric 14C, and therefore supports the site as being capable of providing a high-resolution extension to the âwholly terrestrialâ (i.e. non-reservoir-corrected) calibration curve beyond its present 12,550 cal BP limit
Hepatitis E Virus Antibodies in Patients with Chronic Liver Disease
In the United States, the seroprevalence rate for hepatitis E virus (HEV) is â20%. This study examined HEV seroprevalence in persons with and without chronic liver disease. Our data indicate that HEV seropositivity is high in patients with chronic liver disease and that HEV seroprevalence increases significantly with age
A Complete Terrestrial Radiocarbon Record for 11.2 to 52.8 kyr B.P.
Radiocarbon (14C) provides a way to date material that contains carbon with an age up to ~50,000 years and is also an important tracer of the global carbon cycle. However, the lack of a comprehensive record reflecting atmospheric 14C prior to 12.5 thousand years before the present (kyr B.P.) has limited the application of radiocarbon dating of samples from the Last Glacial period. Here, we report 14C results from Lake Suigetsu, Japan (35°35â˛N, 135°53â˛E), which provide a comprehensive record of terrestrial radiocarbon to the present limit of the 14C method. The time scale we present in this work allows direct comparison of Lake Suigetsu paleoclimatic data with other terrestrial climatic records and gives information on the connection between global atmospheric and regional marine radiocarbon levels
Unexpected elevated alanine aminotransferase, asparte aminotransferase levels and hepatitis E virus infection among persons who work with pigs in accra, ghana
<p>Abstract</p> <p>Background</p> <p>Several studies have suggested that elevated serum alanine aminotransferase (ALT) and asparte aminotransferase (AST) may be markers of hepatitis E virus (HEV) infection. Thus, individuals with elevated ALT and AST may have ongoing subclinical infection of HEV. We estimated the prevalence of anti-HEV antibodies and serum ALT and AST levels among persons who work with pigs in Accra, Ghana.</p> <p>Results</p> <p>Three hundred and fifty- persons who work with pigs provided blood samples for unlinked anonymous testing for the presence of antibodies to HEV, ALT and AST levels. The median age of participants was 32.85 Âą 11.38 years (range 15-70 years). HEV seroprevelance was 34.84%. Anti-HEV IgG was detected in 19.26% while anti-HEV IgM was detected in 15.58% of the persons who tested positive. On multivariate analysis, the independent determinants of HEV infection were, being employed on the farm for less than six months [odds ratio (OR) 8.96; 95% confidence interval (95% CI) 5.43-14.80], having piped water in the household and/or on the farm (OR 13.33; 95% CI 5.23-33.93) and consumption of alcohol (OR 4.91: 95% CI 2.65-9.10). Levels >3Ă the expected maximum were found for both ALT and AST among individuals who tested positive for anti-HEV IgG (ALT, 210.17 Âą 11.64 U/L; AST, 127.18 Âą 11.12 U/L) and anti-HEV IgM (ALT, 200.97 Âą 10.76 U/L; AST, 120.00 Âą 15.96 U/L).</p> <p>Conclusion</p> <p>Consistent with similar studies worldwide, the results of our studies revealed a high prevalence of HEV infection, ALT and AST values in pig handlers.</p
MMP28 (epilysin) as a novel promoter of invasion and metastasis in gastric cancer
Background\ud
The purpose of this study was to investigate invasion and metastasis related genes in gastric cancer.\ud
\ud
Methods\ud
The transwell migration assay was used to select a highly invasive sub-line from minimally invasive parent gastric cancer cells, and gene expression was compared using a microarray. MMP28 upregulation was confirmed using qRT-PCR. MMP28 immunohistochemistry was performed in normal and gastric cancer specimens. Invasiveness and tumor formation of stable cells overexpressing MMP28 were tested in vitro and in vivo.\ud
\ud
Results\ud
MMP28 was overexpressed in the highly invasive sub-cell line. Immunohistochemistry revealed MMP28 expression was markedly increased in gastric carcinoma relative to normal epithelia, and was significantly associated with depth of tumor invasion, lymph node metastasis and poorer overall survival. Ectopic expression of MMP28 indicated MMP28 promoted tumor cell invasion in vitro and increased gastric carcinoma metastasis in vivo.\ud
\ud
Conclusions\ud
This study indicates MMP28 is frequently overexpressed during progression of gastric carcinoma, and contributes to tumor cell invasion and metastasis. MMP28 may be a novel therapeutic target for prevention and treatment of metastases in gastric cancer
Precipitation drives global variation in natural selection
Climate change has the potential to affect the ecology and evolution of every species on Earth. Although the ecological consequences of climate change are increasingly well documented, the effects of climate on the key evolutionary process driving adaptation - natural selection - are largely unknown. We report that aspects of precipitation and potential evapotranspiration, along with the North Atlantic Oscillation, predicted variation in selection across plant and animal populations throughout many terrestrial biomes, whereas temperature explained little variation. By showing that selection was influenced by climate variation, our results indicate that climate change may cause widespread alterations in selection regimes, potentially shifting evolutionary trajectories at a global scale
The gut of the finch: uniqueness of the gut microbiome of the GalĂĄpagos vampire finch.
BACKGROUND: Darwin's finches are a clade of 19 species of passerine birds native to the GalĂĄpagos Islands, whose biogeography, specialized beak morphologies, and dietary choices-ranging from seeds to blood-make them a classic example of adaptive radiation. While these iconic birds have been intensely studied, the composition of their gut microbiome and the factors influencing it, including host species, diet, and biogeography, has not yet been explored. RESULTS: We characterized the microbial community associated with 12 species of Darwin's finches using high-throughput 16S rRNA sequencing of fecal samples from 114 individuals across nine islands, including the unusual blood-feeding vampire finch (Geospiza septentrionalis) from Darwin and Wolf Islands. The phylum-level core gut microbiome for Darwin's finches included the Firmicutes, Gammaproteobacteria, and Actinobacteria, with members of the Bacteroidetes at conspicuously low abundance. The gut microbiome was surprisingly well conserved across the diversity of finch species, with one exception-the vampire finch-which harbored bacteria that were either absent or extremely rare in other finches, including Fusobacterium, Cetobacterium, Ureaplasma, Mucispirillum, Campylobacter, and various members of the Clostridia-bacteria known from the guts of carnivorous birds and reptiles. Complementary stable isotope analysis of feathers revealed exceptionally high δ15N isotope values in the vampire finch, resembling top marine predators. The GalĂĄpagos archipelago is also known for extreme wet and dry seasons, and we observed a significant seasonal shift in the gut microbial community of five additional finch species sampled during both seasons. CONCLUSIONS: This study demonstrates the overall conservatism of the finch gut microbiome over short (<â1 Ma) divergence timescales, except in the most extreme case of dietary specialization, and elevates the evolutionary importance of seasonal shifts in driving not only species adaptation, but also gut microbiome composition
The gut of the finch: uniqueness of the gut microbiome of the GalĂĄpagos vampire finch
Background: Darwinâs finches are a clade of 19 species of passerine birds native to the GalĂĄpagos Islands, whose biogeography, specialized beak morphologies, and dietary choicesâranging from seeds to bloodâmake them a classic example of adaptive radiation. While these iconic birds have been intensely studied, the composition of their gut microbiome and the factors influencing it, including host species, diet, and biogeography, has not yet been explored.
Results: We characterized the microbial community associated with 12 species of Darwinâs finches using high-throughput 16S rRNA sequencing of fecal samples from 114 individuals across nine islands, including the unusual blood-feeding vampire finch (Geospiza septentrionalis) from Darwin and Wolf Islands. The phylum-level core gut microbiome for Darwinâs finches included the Firmicutes, Gammaproteobacteria, and Actinobacteria, with members of the Bacteroidetes at conspicuously low abundance. The gut microbiome was surprisingly well conserved across the diversity of finch species, with one exceptionâthe vampire finchâwhich harbored bacteria that were either absent or extremely rare in other finches, including Fusobacterium, Cetobacterium, Ureaplasma, Mucispirillum, Campylobacter, and various members of the Clostridiaâbacteria known from the guts of carnivorous birds and reptiles. Complementary stable isotope analysis of feathers revealed exceptionally high δ15N isotope values in the vampire finch, resembling top marine predators. The GalĂĄpagos archipelago is also known for extreme wet and dry seasons, and we observed a significant seasonal shift in the gut microbial community of five additional finch species sampled during both seasons.
Conclusions: This study demonstrates the overall conservatism of the finch gut microbiome over short (<â1 Ma) divergence timescales, except in the most extreme case of dietary specialization, and elevates the evolutionary importance of seasonal shifts in driving not only species adaptation, but also gut microbiome composition
- âŚ