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1

Effect of DNA extraction methods on the apparent structure of yak rumen microbial communities as revealed by 16S rDNA sequencing

100%
Chen Y.-B., Lan D.-L., Tang C., Yang X.-N., Li J.
Polish Journal of Microbiology
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2015
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tom 64
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nr 1
To more efficiently identify the microbial community of the yak rumen, the standardization of DNA extraction is key to ensure fidelity while studying environmental microbial communities. In this study, we systematically compared the efficiency of several extraction methods based on DNA yield, purity, and 16S rDNA sequencing to determine the optimal DNA extraction methods whose DNA products reflect complete bacterial communities. The results indicate that method 6 (hexadecyltrimethylammomium bromide-lysozyme-physical lysis by bead beating) is recommended for the DNA isolation of the rumen microbial community due to its high yield, operational taxonomic unit, bacterial diversity, and excellent cell-breaking capability. The results also indicate that the bead-beating step is necessary to effectively break down the cell walls of all of the microbes, especially Gram-positive bacteria. Another aim of this study was to preliminarily analyze the bacterial community via 16S rDNA sequencing. The microbial community spanned approximately 21 phyla, 35 classes, 75 families, and 112 genera. A comparative analysis showed some variations in the microbial community between yaks and cattle that may be attributed to diet and environmental differences. Interestingly, numerous uncultured or unclassified bacteria were found in yak rumen, suggesting that further research is required to determine the specific functional and ecological roles of these bacteria in yak rumen. In summary, the investigation of the optimal DNA extraction methods and the preliminary evaluation of the bacterial community composition of yak rumen support further identification of the specificity of the rumen microbial community in yak and the discovery of distinct gene resources.
2

Measurements of erosion rate of undisturbed sediment under different hydrodynamic conditions in Lake Taihu, China

86%
Li Y., Wang Y., Tang C., Anim D. O., Ni L., Yu Z., Acharya K.
Polish Journal of Environmental Studies
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2014
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tom 23
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nr 4
Sediment erosion and nutrient release play a significant role on the degradation of water quality and eutrophication in large shallow lakes. Lake Taihu, the third largest freshwater lake in China, is suffering severe eutrophication and internal nutrient release. In this paper, sediment cores were sampled in different lake regions to determine sediment properties (e.g. particle size and bulk density), nutrient concentrations in the sediment, etc. Flume experiments were developed to examine the sediment erosion rate by using the undisturbed sediment cores under different hydrodynamic conditions in Lake Taihu. The results showed that the sediment properties exhibited great spatial heterogeneity. Particle sizes decreased with increasing depth of sediment thickness. Sediment bulk density increased with sediment depth. TN concentration increased with sediment depth, while TP concentration didn’t show a similar trend in different sampling sites. Erosion rate is a function of particle size, bulk density, and shear stress. It decreased with increasing sediment depth and decreasing flow velocity. The erosion depth in this study was less than 1cm under the flow velocity of 5 to 30 cm/s, indicating that unidirectional flows have little impact on sediment erosion in Lake Taihu.
3

Distribution and risk assessment of heavy metals in soils from a typical Pb-Zn mining area

86%
Huang S., Yuan C., Li Q., Yang Y., Tang C., Oyuang K., Wang B.
Polish Journal of Environmental Studies
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2017
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tom 26
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nr 3
This study focuses on soil heavy metal pollution and the potential ecological risks associated with mining activities. For this work we collected 83 topsoil samples and 11 soil profile samples from a typical abandoned Pb-Zn mining area in Hunan Province, China. Concentrations of Cd, Pb, Zn, Cu, and Ni were measured using Inductively Coupled Plasma Mass Spectrometry (ICP-MS), and As was analyzed by atomic fluorescence spectometry (AFS). The mean concentrations of As, Pb, Cd, and Zn in topsoil were 84.85, 802.58, 6.13, and 689.66 mg/kg, respectively – much higher than Class III of Environmental Quality Standard for soils in China (GB 15618-1995). The most contaminated areas appeared in the vicinity of the mine, discarded smelter, and tailing pond. Heavy metal contents in soils around the tailing pond increased substantially with soil depth, while first increasing and then decreasing with the increased soil depth around the abandoned smelter. The overall potential ecological risks of soil heavy metals in this abandoned mining area were moderate. However, heavy metals in soils around the tailing pond indicated a severe potential ecological risk, which should give rise to widespread concerns.
4

HIF-1α promotes the migration and invasion of hepatocellular carcinoma cells via the IL-8–NF-κB axis

86%
Feng W., Xue T., Huang S., Shi Q., Tang C., Cui G., Guo H.
Cellular and Molecular Biology Letters
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2018
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tom 23
Background: Hypoxia plays a critical role in many cancers. Hypoxia inducible factor-1α (HIF-1α) is an important mediator of the hypoxia response. It regulates the expression of various chemokines involved in tumor growth, angiogenesis and metastasis but the associated pathway needs further investigation. Methods: The expression level of HIF-1α was determined in hepatocellular carcinoma (HCC) cells. The correlation of interleukin-8 (IL-8) and HIF-1α was assessed by knocking down HIF-1α. These cells were also used to assess its influence on HCC cell migration and invasion was checked. Pyrrolidinedithiocarbamate (PDTC), an inhibitor of NF-κB, was used to confirm the associated signaling pathway. Results: HIF-1α was significantly expressed in HCC cells and found to promote HCC cell migration and invasion in an IL-8-dependent manner. NF-κB was confirmed to be involved in the process. Conclusions: HIF-1α promotes HCC cell migration and invasion by modulating IL-8 via the NF-κB pathway.
5

Hypoxia promotes the migration and invasion of human hepatocarcinoma cells through the HIF-1α–IL-8–Akt axis

86%
Fei M., Guan J., Xue T., Qin L., Tang C., Gong H., Feng W.
Cellular and Molecular Biology Letters
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2018
|
tom 23
Background: Hepatocellular carcinoma (HCC) is the fifth most common cancer and the third most common cause of cancer-related death worldwide. The 5-year survival rate remains low despite considerable research into treatments of HCC, including surgery, radiotherapy and chemotherapy. Many mechanisms within HCC still require investigation, including the influence of hypoxia, which has a crucial role in many cancers and is associated with metastasis. Hypoxia inducible factor-1α (HIF-1α) is known to regulate the expression of many chemokines, including interleukin-8 (IL-8), which is associated with tumor metastasis. Although many studies have reported that HIF-1α is associated with HCC migration and invasion, the underlying mechanisms remain unknown. Methods: The expression level of HIF-1α was determined in HCC cells. The correlation of IL-8 and HIF-1α expressions was assessed via knockdown of HIF-1α. HCC cells were also used to assess the influence of HIF-1α on HCC cell migration and invasion. LY294002, an inhibitor of the Akt pathway, was used to confirm the associated signaling pathways. Results: We observed a significant attenuation of cell migration and invasion after silencing of HIF-1α. Exogenously expressing IL-8 restored migration and invasion. Akt was found to be involved in this process. Conclusion: Hypoxia promotes HCC cell migration and invasion through the HIF-1α–IL8–Akt axis.
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