Total nitrogen is the main soil property associated with soil fungal community in karst rocky desertification regions in southwest China.

Karst rocky desertification (KRD) is a type of land deterioration, resulting in the degraded soil and a delicate ecosystem. Previous studies focused on the influence of KRD on the animals and plants, the impact of KRD on microorganisms, especially soil fungi remains to be discovered. This study reveals the change in the soil fungal community in response to KRD progression in southwest China. Illumina HiSeq was used to survey the soil fungal community. Results showed that the soil fungal community in the severe KRD (SKRD) was noticeably different from that in other KRD areas. Statistical analyses suggested that soil TN was the primary factor associated with the fungal community, followed by pH. Phylum Ascomycota was significantly abundant in non-degraded soils; whereas Basidiomycota predominated in SKRD. The ratio of Ascomycota/Basidiomycota significantly decreased along with KRD progression, which might be used as an indicator of KRD severity. Phylum Basidiomycota was sensitive to changes in all the soil properties but AP. Genus Sebacina might have the potential to promote vegetation and land restoration in KRD areas. This study fills a gap of knowledge on changes in soil fungal communities in accordance with KRD progression.

Soil pH Is the Primary Factor Correlating With Soil Microbiome in Karst Rocky Desertification Regions in the Wushan County, Chongqing, China.

Karst rocky desertification (KRD) is a process of land degradation, which causes desert-like landscapes, deconstruction of endemic biomass, and declined soil quality. The relationship of KRD progression with above-ground communities (e.g. vegetation and animal) is well-studied. Interaction of soil desertification with underground communities, such as soil microbiome, however, is vastly unknown. This study characterizes change in soil bacterial community in response to KRD progression. Soil bacterial communities were surveyed by deep sequencing of 16S amplicons. Eight soil properties, pH, soil organic matter (SOM), total and available nitrogen (TN and AN), total and available phosphorus (TP and AP), and total and available potassium (TK and AK), were measured to assess soil quality. We find that the overall soil quality decreases along with KRD progressive gradient. Soil bacterial community compositions are distinguishingly different in KRD stages. The richness and diversity in bacterial community do not significantly change with KRD progression although a slight increase in diversity was observed. A slight decrease in richness was seen in SKRD areas. Soil pH primarily correlates with bacterial community composition. We identified a core microbiome for KRD soils consisting of; Acidobacteria, Alpha-Proteobacteria, Planctomycetes, Beta-Proteobacteria, Actinobacteria, Firmicutes, Delta-Proteobacteria, Chloroflexi, Bacteroidetes, Nitrospirae, and Gemmatimonadetes in this study. Phylum Cyanobacteria is significantly abundant in non-degraded soils, suggesting that Cyanobacterial activities might be correlated to soil quality. Our results suggest that Proteobacteria are sensitive to changes in soil properties caused by the KRD progression. Alpha- and beta-Proteobacteria significantly predominated in SKRD compared to NKRD, suggesting that Proteobacteria, along with many others in the core microbiome (Acidobacteria, Actinobacteria, Firmicutes, and Nitrospirae), were active in nutrient limiting degraded soils. This study demonstrates the relationship of soil properties with bacterial community in KRD areas. Our results fill the gap of knowledge on change in soil bacterial community during KRD progression.

Application value of endoscopic submucosal dissection and endoscopic mucosal resection for treatment of rectal carcinoids.

OBJECTIVE: The objective of this study is to explore the clinical effect and safety of endoscopic submucosal dissection (ESD) and endoscopic mucosal resection (EMR) for treatment of rectal carcinoids. METHODS: A retrospective analysis was conducted on 42 patients with rectal carcinoids who were hospitalized and subjected to surgical treatment in our hospital from January 2010 to November 2015. The patients were categorized into two groups based on treatment received: ESD (n = 22) and EMR (n = 20). The patients were analyzed and compared to determine differences in lesion size, operation time, histopathologically curative resection rate, intraoperative complications, complete lesion resection rate, and postoperative recurrence rate between the two groups. RESULTS: Operation time (25.2 ± 20.1 min) and wound surface diameter (36.2 ± 10.1 mm) were significantly higher in the ESD group than those in the EMR group (12.6 ± 8.4 min and 18.6 ± 5.9 mm, respectively) (P < 0.05). The differences in complete lesion and histopathologically curative resection rates between the two groups were not statistically significant (P > 0.05). Delayed hemorrhage was the primary postoperative complication in both groups. Postoperative follow-up was performed for 3-71 months, and the median follow-up time was 45 months. Recurrence was noted 32 months after surgery in one patient in the EMR group (4.5%), whereas recurrence was not detected in the ESD group. CONCLUSION: ESD and EMR are safe and effective methods for treatment of rectal carcinoids. Moreover, ESD had less risk of recurrence, more complete resection rate which could provide more information for postoperative treatment.

[A comparison study on the species diversity between the gap and non-gap in Jinyun Mountain].

The species diversity and community stability of gap and non-gap stands in Jinyun Mountain were studied by using species richness index(dGL), Shannon-Weiner index, Pielou evenness index(J), Simpson index(D), ecological dominance(lambda), evenness-dominance-abundance index(Z) and community dominance(C). The results showed that the dGL, H', J and D calculated by individuals numbers in gap are 12.14, 4.62, 0.70, 13.32, respectively. Shrub layer plays a greater role than other layers. The corresponding indices in non-gap stand are 6.32, 3.74, 0.66 and 8.16, respectively, which were lower than those in gap. Species diversity indices of the community were far higher in gap than in non-gap. However, ecological dominance and community dominance in gap were smaller than those in non-gap significantly. It suggested that species diversity of the community increased, and community stability decreased, due to the existence of gap formed by natural or human disturbance.