Differences of Gut Microbiota in the Freshwater Blackworm (Lumbriculus variegatus: Oligochaeta) in Two Different Habitat Conditions.

The distribution of organisms is governed by their habitat condition. We analyzed bacterial communities in the gut of the blackworm Lumbriculus variegatus by pyrosequencing of the extracted intestinal metagenomic DNA. Blackworms were collected from two sampling sites with differences in irradiance and riparian vegetation, where site GP7 was covered by riparian vegetation and site GP8 was exposed to sunlight. We obtained the filtered 6414 reads from three samples of each site. At GP7, 271 OTUs were identified, including 32 OTUs unique to the site, whereas at GP8, 238 OTUs were identified, including 22 unique OTUs. Among them, 18 OTUs were shared between both sites. The phylum Proteobacteria was a major component contributing 67.84% and 64.05% of sequences at sites GP7 and GP8, respectively, while each remaining phylum contributed less than 10% at both sites. The two sites differed in microbial community composition and KEGG-indicated biochemical pathways. Community indices such as species richness and Shannon diversity were higher at site GP7 than at GP8. Meanwhile, the abundance of Cyanobacteria was significantly higher at site GP8, while site GP7 showed a greater proportion of genes for membrane transport and carbohydrate metabolism, reflecting differences in food resources.

Planar cell polarity signaling components are a direct target of ß-amyloid-associated degeneration of glutamatergic synapses.

The signaling pathway directly controlling the maintenance of adult glutamatergic synapses has not been well understood. Planar cell polarity (PCP) signaling components were recently shown to play essential roles in the formation of glutamatergic synapses. Here, we show that they are localized in the adult synapses and are essential for their maintenance. Synapse loss at early stages of Alzheimer's disease is thought to be induced by ß-amyloid (Aß) pathology. We found that oligomeric Aß binds to Celsr3 and assists Vangl2 in disassembling synapses. Moreover, a Wnt receptor and regulator of PCP signaling, Ryk, is also required for Aß-induced synapse loss. In the 5XFAD mouse model of Alzheimer's disease, Ryk conditional knockout or a function-blocking monoclonal Ryk antibody protected synapses and preserved cognitive function. We propose that tipping of the fine balance of Wnt/PCP signaling components in glutamatergic synapses may cause synapse degeneration in neurodegenerative disorders with Aß pathology.

Modeling Occurrence of Urban Mosquitos Based on Land Use Types and Meteorological Factors in Korea.

Mosquitoes are a public health concern because they are vectors of pathogen, which cause human-related diseases. It is well known that the occurrence of mosquitoes is highly influenced by meteorological conditions (e.g., temperature and precipitation) and land use, but there are insufficient studies quantifying their impacts. Therefore, three analytical methods were applied to determine the relationships between urban mosquito occurrence, land use type, and meteorological factors: cluster analysis based on land use types; principal component analysis (PCA) based on mosquito occurrence; and three prediction models, support vector machine (SVM), classification and regression tree (CART), and random forest (RF). We used mosquito data collected at 12 sites from 2011 to 2012. Mosquito abundance was highest from August to September in both years. The monitoring sites were differentiated into three clusters based on differences in land use type such as culture and sport areas, inland water, artificial grasslands, and traffic areas. These clusters were well reflected in PCA ordinations, indicating that mosquito occurrence was highly influenced by land use types. Lastly, the RF represented the highest predictive power for mosquito occurrence and temperature-related factors were the most influential. Our study will contribute to effective control and management of mosquito occurrences.