Changes in microbial composition explain the contrasting responses of glucose and lignin decomposition to soil acidification in an alpine grassland

Soil acidification often suppresses microbial growth and activities, resulting in a negative impact on soil organic carbon (C) decomposition. While the detrimental effects of acidification on soil and plant properties have been extensively studied, less attention has been paid on the shifts in soil microbial communities and their influences of the decomposition of organic C with different chemical complexities. Taking advantage of an acid addition experiment in a Tibetan alpine meadow, here we examined the response of soil microbial communities to soil acidification and microbial effect on the decomposition of organic C with different chemical complexities (i.e., glucose and lignin, representing labile and recalcitrant C respectively). We found that soil acidification had no impact on microbial respiration and microbial abundance even though it decreased bacterial diversity significantly. Soil acidification increased the relative abundance of some microbial taxa, like Alphaproteobacteria and Acidobacteriia in bacteria increased by 36 %, 284 %, and Eurotiomycetes, Sordariomycetes and Leotiomycetes in fungi increased by 145 %, 279 % and 12.7-fold, but decreased the relative abundance of Acidimicrobiia by 33 % in highest acid addition treatment. Changes in microbial communities (bacterial and fungal community composition, the diversity of bacterial community and the ratio of fungi to bacteria) are significantly related to the decomposition of glucose and lignin. More specifically, soil acidification decreased the decomposition of glucose but increased the decomposition of lignin, indicating a trade-off between the decomposition of labile and recalcitrant soil organic C under soil acidification. Overall, shifts in microbial communities under soil acidification might be accompanied by an increased ability to break down more recalcitrant C. This trade-off between the decomposition of labile and recalcitrant C may change soil C quality under future acid deposition scenarios.

Comparison of two series of non-invasive instruments used for the skin physiological properties measurements: the DermaLab® from Cortex Technology vs. the series of detectors from Courage & Khazaka

BACKGROUND/PURPOSE

The detectors from Courage & Khazaka and DermaLab^® from Cortex Technology were two series of the most commonly used non-invasive instruments for the skin physiological properties measurements. The aim of this study is to reveal the differences and correlations in measuring skin color, hydration, transepidermal water loss (TEWL), sebum and elasticity on the forearm or faces between two commercially available series of instruments.

METHODS

30 subjects were enrolled to be measured by the two series of instruments. The measurements by each series were performed on the left/right side of the body randomly. The hydration, sebum, elasticity and TEWL measurements were performed on different sites.

RESULTS

Positive correlations were found in the values of skin color, hydration, TEWL, sebum and visco-elasticity detected by the two series. The values related to skin firmness measured by the two instruments were statistically negative correlated. Contrary to the results in measuring the skin color, the detectors from Courage & Khazaka presented lower values of variation in measuring skin hydration and TEWL than those from DermaLab^® .

CONCLUSION

The two series have significant correlations.The differences of the two series can be due either to differences in the design of the probe or left/right part of the body.

[Cross-section anatomy of the subphrenic spaces]

The cross-section anatomy of the subphrenic spaces were investigated in 20 Chinese cadavers. On the horizontal sections, the subphrenic spaces consist of the perihepatic and perisplenic spaces. The fissure for ligamentum venosum was separated into two parts by the lesser omentum, the anterior part communicates with gastrohepatic recess, the posterior is the superior recess of the omental bursa into which the caudate lobe of the liver projected. The bare area of the stomach encroaches upon the posterior surface of the gastric fundus between the right and left layers of the gastrophrenic ligament and lies between the superior and splenic recesses of the omental bursa. Left subphrenic retroperitoneal space is between the bare area of the stomach and the diaphragm.