Microbial communities are indicators of parasite infection status

Growing evidence suggests that microbiomes have been shaping the evolutionary pathways of macroorganisms for millennia and that these tiny symbionts can influence, and possibly even control, species interactions like host-parasite relationships. Yet, while studies have investigated host-parasites and microbiomes separately, little has been done to understand all three groups synergistically. Here, we collected infected and uninfected Eurypanopeus depressus crab hosts from a coastal North Carolina oyster reef three times over 4 months. Infected crabs demonstrated an external stage of the rhizocephalan parasite, Loxothylacus panopaei. Community analyses revealed that microbial richness and diversity were significantly different among tissue types (uninfected crab, infected crab, parasite externae and parasite larvae) and over time (summer and fall). Specifically, the microbial communities from parasite externae and larvae had similar microbiomes that were consistent through time. Infected crabs demonstrated microbial communities spanning those of their host and parasite, while uninfected crabs showed more distinctive communities with greater variability over time. Microbial communities were also found to be indicators of early-stage infections. Resolving the microbial community composition of a host and its parasite is an important step in understanding the microbiome's role in the host-parasite relationship and determining how this tripartite relationship impacts coevolutionary processes.

Microecological health assessment of water environment and sediment based on metagenomics: a case study of Guixi River in Chongqing, China

River sediment is vital in containing water pollution and strengthening water remediation. This paper has conducted a study on the microecological health assessment of the sediment and water body of Guixi River in Dianjiang, Chongqing, China, using metagenomics sequencing and microbial biological integrity index (M-IBI) technology. The analysis of physical and chemical characteristics shows that the concentration of TN varies from 2.62 to 9.76 mg/L in each sampling section, and the eutrophication of the water body is relatively severe. The proportion of Cyanobacteria in the sampling section at the sink entrance is higher than that of other sites, where there are outbreaks of water blooms and potential hazards to human health. The dominant functions of each site include carbon metabolism, TCA cycle, and pyruvate metabolism. In addition, the main virulence factors and antibiotic resistance genes in sediment are Type IV pili (VF0082), LOS (CVF494), MymA operon (CVF649), and macrolide resistance genes macB, tetracyclic tetA (58), and novA. Correlation analysis of environmental factors and microorganisms was also performed, and it was discovered that Thiothrix and Acidovorax had obvious gene expression in the nitrogen metabolism pathway, and the Guixi River Basin had a self-purification capacity. Finally, based on the microecological composition of sediment and physical and chemical characteristics of the water body, the health assessment was carried out, indicating that the main pollution area was Dianjiang Middle School and the watershed near the sewage treatment plant. The findings should theoretically support an in-depth assessment of the water environment's microecological health.

The streamwater microbiome encodes hydrologic data across scales

Many fundamental questions in hydrology remain unanswered due to the limited information that can be extracted from existing data sources. Microbial communities constitute a novel type of environmental data, as they are comprised of many thousands of taxonomically and functionally diverse groups known to respond to both biotic and abiotic environmental factors. As such, these microscale communities reflect a range of macroscale conditions and characteristics, some of which also drive hydrologic regimes. Here, we assess the extent to which streamwater microbial communities (as characterized by 16S gene amplicon sequence abundance) encode information about catchment hydrology across scales. We analyzed 64 summer streamwater DNA samples collected from subcatchments within the Willamette, Deschutes, and John Day river basins in Oregon, USA, which range 0.03-29,000 km² in area and 343-2334 mm/year of precipitation. We applied information theory to quantify the breadth and depth of information about common hydrologic metrics encoded within microbial taxa. Of the 256 microbial taxa that spanned all three watersheds, we found 9.6 % (24.5/256) of taxa, on average, shared information with a given hydrologic metric, with a median 15.6 % (range = 12.4-49.2 %) reduction in uncertainty of that metric based on knowledge of the microbial biogeography. All of the hydrologic metrics we assessed, including daily discharge at different time lags, mean monthly discharge, and seasonal high and low flow durations were encoded within the microbial community. Summer microbial taxa shared the most information with winter mean flows. Our study demonstrates quantifiable relationships between streamwater microbial taxa and hydrologic metrics at different scales, likely resulting from the integration of multiple overlapping drivers of each. Streamwater microbial communities are rich sources of information that may contribute fresh insight to unresolved hydrologic questions.

Benthic Biofilm Bacterial Communities and Their Linkage with Water-Soluble Organic Matter in Effluent Receivers

Benthic biofilms are pioneering microbial aggregates responding to effluent discharge from wastewater treatment plants (WWTPs). However, knowledge of the characteristics and linkage of bacterial communities and water-soluble organic matter (WSOM) of benthic biofilms in effluent-receiving rivers remains unknown. Here, we investigated the quality of WSOM and the evolution of bacterial communities in benthic biofilm to evaluate the ecological impacts of effluent discharge on a representative receiving water. Tryptophan-like proteins showed an increased proportion in biofilms collected from the discharge area and downstream from the WWTP, especially in summer. Biofilm WSOM showed weak humic character and strong autochthonous components, and species turnover was proven to be the main factor governing biofilm bacteria community diversity patterns. The bacterial community alpha diversity, interspecies interaction, biological index, and humification index were signally altered in the biofilms from the discharge area, while the values were more similar in biofilms collected upstream and downstream from the WWTP, indicating that both biofilm bacterial communities and WSOM characters have resilience capacities. Although effluent discharge simplified the network pattern of the biofilm bacterial community, its metabolic functional abundance was basically stable. The functional abundance of carbohydrate metabolism and amino acid metabolism in the discharge area increased, and the key modules in the non-random co-occurrence network also verified the important ecological role of carbon metabolism in the effluent-receiving river. The study sheds light on how benthic biofilms respond to effluent discharge from both ecological and material points of view, providing new insights on the feasibility of utilizing benthic biofilms as robust indicators reflecting river ecological health.

Viral metagenomes of Lake Soyang, the largest freshwater lake in South Korea

A high number of viral metagenomes have revealed countless genomes of putative bacteriophages that have not yet been identified due to limitations in bacteriophage cultures. However, most virome studies have been focused on marine or gut environments, thereby leaving the viral community structure of freshwater lakes unclear. Because the lakes located around the globe have independent ecosystems with unique characteristics, viral community structures are also distinctive but comparable. Here, we present data on viral metagenomes that were seasonally collected at a depth of 1 m from Lake Soyang, the largest freshwater reservoir in South Korea. Through shotgun metagenome sequencing using the Illumina MiSeq platform, 3.08 to 5.54-Gbps of reads per virome were obtained. To predict the viral genome sequences within Lake Soyang, contigs were constructed and 648 to 1,004 putative viral contigs were obtained per sample. We expect that both viral metagenome reads and viral contigs would contribute in comparing and understanding of viral communities among different freshwater lakes depending on seasonal changes.

The bacterial community structures in response to the gut passage of earthworm (Eisenia fetida) feeding on cow dung and domestic sludge: Illumina high-throughput sequencing-based data analysis

Diets are shown to be capable of shaping the gut microbiota of earthworm, while the effects of distinct foods on bacterial communities of different digestive tracts of earthworm are unknown. For this purpose, cow dung (CD) and domestic sludge (DS) were chosen as diets for earthworms (Eisenia fetida), and different gut contents, namely gizzard + foregut area, hindgut, and mature vermi-compost were sampled for Illumina sequencing analysis. We found that there existed significant reductions in bacterial diversity and abundance in the gizzard + foregut area, where there were stable bacteria with the ability of biodegradation of xenobiotics, such as Amycolatopsis, Methylobacterium, Ralstonia, Ochrobactrum, and Sphingomonas. The decreases could be recovered in the hindgut and mature vermi-compost to different extents, suggesting that a bottleneck effect on the bacterial community occurred in the gizzard + foregut area. Beta-Proteobacteria was the most abundant subclass regardless of the different diets, and bacteria affiliated with gamma-, delta- and epsilon-subclasses were taken as food by the earthworms. Vermi-composts based on the various diets should be used differently according to different aims.

Arsenicibacter rosenii gen. nov., sp. nov., an efficient arsenic methylating and volatilizing bacterium isolated from an arsenic-contaminated paddy soil

A novel bacterium with strong arsenic (As) methylation and volatilization abilities, designated strain SM-1T, was isolated from an As-contaminated paddy soil. SM-1T is strictly aerobic, rod-shaped, non-motile, Gram-negative and orange-coloured. Phylogenetic analysis revealed that strain SM-1T showed low 16S rRNA gene sequence similarities (≤88 %) to members of established genera in the family Cytophagaceae. Growth of this strain was observed at 15-45 °C (optimum, 37 °C), pH 6.0-8.0 (optimum, 7.0) and 0-0.5 % (w/v) NaCl. The major cellular fatty acids were C16 : 1ω5c and iso-C15 : 0. The respiratory quinone was MK-7, and the predominant polar lipids were phosphatidylethanolamine, an unidentified lipid (L), and an unidentified aminolipid (AL2). The DNA G+C content was 51.5 mol%. On the basis of phenotypic, phylogenetic and chemotaxonomic properties, strain SM-1T represents a novel species in a new genus within the family Cytophagaceae, for which the name Arsenicibacter rosenii gen. nov., sp. nov. is proposed. The type strain of Arsenicibacter rosenii is SM-1T (=CCTCC AB 2017086T=KCTC 52624T).

Lacihabitans lacunae sp. nov., isolated from a lagoon

A non-motile, orange-pigmented bacterium, designated strain HME7103T, was isolated from lagoon water in the Republic of Korea. A phylogenetic tree based on 16S rRNA gene sequences showed that strain HME7103T formed a lineage within the genus Lacihabitans and family Cytophagaceae. Strain HME7103T was closely related to Lacihabitans soyangensis HME6675T (95.7 % 16S rRNA gene sequence similarity). The major fatty acids of strain HME7103T were summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c) and iso-C15 : 0. The major respiratory quinone was MK-7. The major polyamine was spermidine. The major polar lipids were phosphatidylethanolamine, two unidentified aminolipids, one unidentified aminophospholipid and three unidentified polar lipids. The DNA G+C content of strain HME7103T was 40.6 mol%. On the basis of the evidence presented in this study, strain HME7103T represents a novel species within the genus Lacihabitans, for which the name Lacihabitans lacunae sp. nov. is proposed. The type strain is HME7103T (=KCTC 23619T=CECT 7956T).

Arcticibacterium luteifluviistationis gen. nov., sp. nov., isolated from Arctic seawater

A Gram-staining-negative, aerobic, non-motile and yellow-pigmented bacterium, designated strain SM1504T, was isolated from Arctic seawater. It hydrolysed aesculin and gelatin but did not reduce nitrate to nitrite. Phylogenetic analysis of 16S rRNA gene sequences revealed that strain SM1504T constituted a distinct phylogenetic line within the family Cytophagaceae and was closely related to species of the genera Lacihabitans, Emticicia, Fluviimonas and Leadbetterella, with respect to which low sequence similarities between 88.9 and 91.6 % were observed. The major fatty acids of strain SM1504T were summed feature 3 (comprising C16 : 1ω7c and/or iso-C15 : 0 2-OH) and iso-C15 : 0. The predominant polar lipids of strain SM1504T were phosphatidylethanolamine and one unidentified lipid. The only respiratory quinone detected in strain SM1504T was MK7. The DNA G+C content of strain SM1504T was 40.8 mol%. On the basis of the phylogenetic, chemotaxonomic and phenotypic characterization in this study, strain SM1504T is considered to represent a novel species in a new genus of the family Cytophagaceae, for which the name Arcticibacterium luteifluviistationis gen. nov., sp. nov. is proposed. The type strain is SM1504T (=KCTC 42716T=CCTCC AB 2015348T).

Taeseokella kangwonensis gen. nov., sp. nov., isolated from a freshwater reservoir

A Gram-stain-negative, non-motile and yellow-pigmented bacterium, designated HME8275T, was isolated from freshwater in Korea. The major fatty acids of strain HME8275T were summed feature 3 (comprising C16 : 1ω6c and/or C16 : 1ω7c), C16 : 0 and iso-C15 : 0. The only respiratory quinone was MK-7. Polar lipid analysis showed phosphatidylethanolamine, two unidentified aminolipids, two unidentified aminophospholipids and three unidentified polar lipids. The DNA G+C content of strain HME8275T was 37.6 mol%. A phylogenetic tree based on 16S rRNA gene sequences showed that strain HME8275T formed a lineage within the family Cytophagaceae and was related to Lacihabitans soyangensis HME6675T (92.6 % 16S rRNA gene sequence similarity), Leadbetterella byssophila 4M15T (89.0 %), Fluviimonas pallidilutea TQQ6T (89.7 %) and Emticicia oligotrophica GPTSA100-15T (89.8 %). On the basis of the evidence presented in this study, strain HME8275T represents a novel species of a new genus in the family Cytophagaceae, for which the name Taeseokella kangwonensis, gen. nov., sp. nov. is proposed. The type strain of the type species is HME8275T ( = KACC 16933T = CECT 8198T).