Comparison and Correlation of Corynespora cassiicola Populations from Kiwifruit and Other Hosts Based on Morphology, Phylogeny, and Pathogenicity.

Corynespora leaf spot, which is caused by Corynespora cassiicola (Berk. & M. A. Curtis) C.T. Wei (C. cassiicola), has been globally reported in many plant species. 'Hongyang' was reported as highly sensitive kiwifruit cultivar to C. cassiicola. This cultivar is an important germplasm resource in the Actinidiaceae family and is widely cultivated throughout China. Even though C. cassiicola has been identified as the pathogen associated with kiwifruits in China, the C. cassiicola population from kiwifruit has not been characterized based on morphology, phylogeny, and pathogenicity. In this study, 133 and 48 representative C. cassiicola isolates from kiwifruit and 11 other hosts, respectively, recovered from symptomatic leaves were classified into eight morphological subgroups based on host origins. Using three loci (rDNA ITS, caa5, and act1), a phylogenetic tree showed that C. cassiicola isolates in Sichuan Province were grouped into three clades. All kiwifruit isolates were genetically identical to the rubber isolates from different countries. However, most isolates from other hosts in this study were genetically identical to the cucumber, soybean, and cowpea isolates in China, Brazil, and the United States, and two strawberry isolates clustered with isolates from tomato and other hosts in China, Brazil, and the United States. Furthermore, we confirmed host shift of C. cassiicola among different plant species in this study. Although 51 isolates from kiwifruit and different hosts were pathogenic to kiwifruit, blueberry, cucumber, and soybean, virulence levels of the pathogen were diverse for four hosts. Kiwifruit isolates exhibited host specificity with regards to the original host in degree. In addition, those isolates revealed a correlation between morphology and pathogenicity. The results suggest that C. cassiicola in Sichuan Province were derived from three different phylogenetic lineages. Promotion of the susceptible 'Hongyang' cultivar led to the emergence of a regnant C. cassiicola population from kiwifruit. In conclusion, rapid development of the C. cassiicola-sensitive crop in agricultural systems led to the emergence of a regnant C. cassiicola population. In some dominant populations (e.g., the C. cassiicola population from kiwifruit in this study), host origin was found to be a key factor influencing the morphologic, genetic, and pathogenic characterization of C. cassiicola.

Anthropogenic-driven chronological increase of sediment organic carbon burial in a river-lake system.

Total organic carbon (TOC) in lake sediments from upstream catchments is deposited and buried in substrate, recording historical environmental changes. However, the linkage among natural variability, anthropogenic activity, and TOC burial for has not yet been clarified. This study examined the lake sediments of five 200-cm-deep dated depositional cores in west Dongting lake, China to quantify the magnitude, allocation, and amplitude of TOC burial. 44.47-59.36% of TOC burial flux was buried at 100-200 cm, suggesting lake sediments at deep layers stored considerable carbon. TOC burial rate (BRTOC) decreased along the lake entrance to its body, which was explained by the geochemical differences. Since 1900, BRTOC presented an increasing with a 4-7 times uptrend, showing three sedimentary stages with the increased human disturbance, such as deforestation, hydroelectric facilities. Moreover, the coefficient of variation of BRTOC in the third stage was lower than that in the second stage for the implementation of watershed reforestation and reservoir construction. Our findings stressed that natural variations of lake sedimentation background induced the change of TOC burial among the depositional sites, and enhanced that anthropogenic perturbation drove its chronological increases. This research unveiled the linkage between TOC burial, natural variability, and human disturbance from the perspective of burial evolutions in a lacustrine sedimentary environment.

Comprehensive gastroenterology endoscopy unit workflow and infection prevention during the COVID-19 Pandemic: Experience with 159 cases in Wuhan, China.

During the outbreak of the novel coronavirus disease (COVID-19) in Wuhan, the gastroenterology department of our hospital performed gastrointestinal endoscopy procedures using strict infection control measures. Thorough screening of incoming patients, separation of diagnostic and treatment areas, regional management, hierarchical protection, disinfection protocols, and other measures were enforced to prevent virus transmission during endoscopic treatments. During the COVID-19 pandemic, between February and March 2020, 159 endoscopic examinations and treatments were performed, including emergency endoscopy for 17 patients. Among these, seven patients were either previously infected with or were suspected carriers of the virus. Using the aforementioned control measures, we did not encounter a single case of cross-infection or infection among the patients or staff. The presented protocols may provide valuable insight regarding how to protect gastroenterology endoscopy units during the novel coronavirus disease pandemic.

Water Colour Shapes Diving Beetle (Coleoptera: Dytiscidae) Assemblages in Urban Ponds.

Dramatic land-use changes in urban landscapes can drive water colour darkening by washing compounds, such as organic matter and iron, from terrestrial ecosystems into urban blue space, consequentially affecting aquatic communities. Here, I studied how pond water colour changes along an urban gradient and how diving beetles (Dytiscidae) respond to the water colour gradient in 11 ponds with fish and 15 ponds without fish in the Helsinki Metropolitan Area, Finland. I found that the pond water colour exhibited a non-significant decreasing pattern along the urban gradient, indicating that urbanisation may not necessarily drive brownification in urban ponds. Dytiscid species richness and abundance exhibited significant positive correlations with increasing water colour in ponds with fish but no significant correlation in ponds without fish. Some species, such as Agabus spp. and Dytiscus spp., appeared tolerant to highly coloured water, whereas some species, such as Hyphydrus ovatus and Hygrotus spp., tended to occur in clear water, indicating that brown water may provide dytiscids with prey refuges, but some species are intolerant to brown water. The study highlights the importance of urban pondscape heterogeneity to meet the needs of aquatic invertebrates that prefer different water colours and for the multifunctioning of urban ponds.

Unsedated versus sedated gastrointestinal endoscopy: a questionnaire investigation in Wuhan, central China.

National data show that in China mainland unsedated gastrointestinal (GI) endoscopy has been applied in most hospitals for clinical examination, while sedated GI endoscopy is only performed in some hospitals. The purpose of this study was to compare sedated versus unsedated GI endoscopy regarding cost, safety, degree of comfort, tolerance level and overall satisfaction of patients over a 6-month period investigation. From March to September 2011, a questionnaire survey was performed on 1800 patients and 30 physicians at Zhongnan Hospital of Wuhan University and Wuhan General Hospital of Guangzhou Military Command. The patients fell into two groups according to their own decisions: the unsedated group (n=1000) and the sedated group (n=800). After examination, the patients and the physicians were required to fill in a questionnaire form. All the data were analyzed statistically. The results showed that the main factors the patients took for consideration between sedated and unsedated procedures included economy, comfort and safety. The income levels between the sedated and unsedated groups showed significant difference (P<0.01). Most patients in the unsedated group had lower income and were covered by less medical insurance. The tolerance rate was 92.4% vs. 65.5% between the sedated and unsedated group, respectively. 95.5% patients in the sedated group and 72.1% patients in the unsedated group chose the same endoscopy procedure for repeat examination. The survey data from endoscopists suggested the sedated procedure was more comfortable but less safe than the unsedated procedure (P<0.01). In China, unsedated GI endoscopy is now widely accepted by the majority of patients due to low cost and safety. Compared to unsedated GI endoscopy, sedated GI endoscopy is less painful, but more expensive and less safe. With the rapid improvement of people's living standard and the reliability of sedation technology, we expect sedated GI endoscopy will be gradually accepted by more patients.

Characteristics of microbial community composition and its relationship with carbon, nitrogen and sulfur in sediments.

Microorganisms play an important role in the biogeochemical cycles of lacustrine sediments. However, little is known about their vertical responses to sedimentary depths and their contributions to important element cycles such as carbon, nitrogen and sulfur. Here, we investigated the community features of sedimental prokaryotes along with vertical profiles (i.e., sedimental depths of 0-230 cm) in the Dongting watershed. In the entire profile, the bacterial diversity wavelike decreased with increasing sediment depths, whereas archaeal diversity increased monotonically in the deep layer (100-230 cm). Bacteria were more sensitive to sedimental depths than archaea (B: P < 0.001, R = 0.534; A: P < 0.001, R = 0.327). The relative abundance of the primary phylum of bacteria (e.g. Proteobacteria) and archaea (e.g. Thaumarchaeota) changed significantly with sediment layers (P < 0.05). The vertical distribution of prokaryotes in sediments was related to the changes in sediment properties (P < 0.05, e.g., the content of nutrients, pH, texture, etc.). The co-occurrence network analysis further indicated that the superficial (0-40 cm) and deep (100-230 cm) networks contained more tightly connected node groups (more modules number), while the tighter connections (shorter APL) and more complex networks (higher avgK) were seen in sub-deep (40-100 cm) sediments. Based on the FAPROTAX database, we found that the predicted prokaryotic microbial functional groups involved in the N cycle had the highest abundance (87.47%), followed by the C cycle (9.48%) and the S cycle (2.39%). In addition, these groups were enriched in the superficial and deep layers. Taken together, these results reveal a new perspective on the vertical spatial variation in microorganisms at the fine-scale of the lake sediments. Distinct microbiome response patterns may have important implications for carbon, nitrogen and sulfur cycling along with the sediment profile in Dongting lake ecosystems.

Chronological records of sediment organic carbon at an entrance of Dongting Lake: Response to historical meteorological events.

Lake sediments are the products of soil erosion and are strongly influenced by climate variability, particularly extreme meteorological events. Sediment organic carbon (SOC) can reflect environmental changes that affect sediment transport. However, the response of SOC chronological records to major meteorological events is relatively unknown. This study explored the chronological regularity of SOC and verified its variations using major historical meteorological events. Based on three sediment profiles with a depth of 230 cm at the Yuan River entrance to the West Dongting Lake (Hanshou entrance), the SOC chronology was reconstructed by employing the sedimentation rates calculated by 137Cs and 210Pb. The sedimentary environment then was interpreted via comparisons and quantitative analysis. The grain distribution and the S-shaped distribution of SOC reflected the general deposition regularity of organic carbon in lake sediments, which gradually stabilized with depth. The average sedimentation rates based on 137Cs and 210Pb were 1.310 and 1.319 cm a-1, respectively. Accordingly, SOC records covered the past 76 years via dating (0-100 cm), during which the SOC content first increased and subsequently stabilized. By comparing the data with the occurrence of 11 major historical meteorological events, we found that SOC generally increased after these events. Moreover, the frequent occurrence of meteorological events stabilized the SOC content. Severe floods had a greater impact on SOC content than severe droughts, causing SOC to change by up to 20.24% and 8.77%, respectively. Our findings suggest that major historical meteorological events can verify SOC chronological records, thereby highlighting their significant impacts on organic carbon variations in sediments.