Different types of agricultural land use drive distinct soil bacterial communities.

Biogeographic patterns in soil bacterial communities and their responses to environmental variables are well established, yet little is known about how different types of agricultural land use affect bacterial communities at large spatial scales. We report the variation in bacterial community structures in greenhouse, orchard, paddy, and upland soils collected from 853 sites across the Republic of Korea using 16S rRNA gene pyrosequencing analysis. Bacterial diversities and community structures were significantly differentiated by agricultural land-use types.

Occurrence of four waterborne viruses at five typical raw water resources in the Republic of Korea during August 2013 to February 2019.

Waterborne diseases have critical public health issues and socioeconomic relevancy worldwide. Various viral pathogens are ordinarily associated with waterborne diseases. Six-year-surveillance (a total of 20 times) of norovirus, hepatitis A virus, group C rotavirus, and enterovirus was conducted at five raw water sampling sites including two lakes (Lakes Soyang and Juam), Hyundo region of Geum River in Daejeon City, and Guui region of Han River in Seoul Metropolitan City and Moolgeum region of Nakdong River in Gimhae City which are located near two water intake plants.

A preliminary examination of bacterial, archaeal, and fungal communities inhabiting different rhizocompartments of tomato plants under real-world environments.

Plant microbiota is a key determinant of plant health and productivity. The composition and structure of plant microbiota varies according to plant tissue and compartment, which are specific habitats for microbial colonization. To investigate the structural composition of the microbiome associated with tomato roots under natural systems, we characterized the bacterial, archaeal, and fungal communities of three belowground compartments (rhizosphere, endosphere, and bulk soil) of tomato plants collected from 23 greenhouses in 7 geographic locations of South Korea.

Effects of Extended Storage of Chlorhexidine Gluconate and Benzalkonium Chloride Solutions on the Viability of Burkholderia cenocepacia.

Chlorhexidine gluconate (CHX) and benzalkonium chloride (BZK) formulations are frequently used as antiseptics in healthcare and consumer products. Burkholderia cepacia complex (BCC) contamination of pharmaceutical products could be due to the use of contaminated water in the manufacturing process, over-diluted antiseptic solutions in the product, and the use of outdated products, which in turn reduces the antimicrobial activity of CHX and BZK. To establish a "safe use" period following opening containers of CHX and BZK, we measured the antimicrobial effects of CHX (2-10 μg/ml) and BZK (10-50 μg/ml) at sublethal concentrations on six strains of using chemical and microbiological assays.

Arthrobacter silviterrae sp. nov., isolated from forest soil.

A novel actinomycete strain, designated KIS14-16, was isolated from forest soil in Ongjin county, South Korea and characterized using polyphasic taxonomy. The cells are aerobic, Gram-stain-positive, non-flagellated and short rods. The strain grew in a temperature range of 4-33 °C (optimum, 28-30 °C) and pH range of 5.

Parapedobacter lycopersici sp. nov., isolated from the rhizosphere soil of tomato plants (Solanum lycopersicum L.).

A novel Gram-stain-negative bacterial strain, designated T16R-256, was isolated from the rhizosphere soil of tomato plants grown in a greenhouse in Yecheon-gun, Gyeongsangbuk-do, Republic of Korea and characterized using polyphasic taxonomy. Cells were aerobic, non-flagellated and rod-shaped. Colonies were light yellow, convex and round.

Effects of diet type, developmental stage, and gut compartment in the gut bacterial communities of two Cerambycidae species (Coleoptera).

The gut bacterial community of wood-feeding beetles has been examined for its role on plant digestion and biocontrol method development. Monochamus alternatus and Psacothea hilaris, both belonging to the subfamily Lamiinae, are woodfeeding beetles found in eastern Asia and Europe and generally considered as destructive pests for pine and mulberry trees, respectively. However, limited reports exist on the gut bacterial communities in these species.

Comparative analysis of bacterial diversity in the rhizosphere of tomato by culture-dependent and -independent approaches.

The microbiome in the rhizosphere-the region surrounding plant roots-plays a key role in plant growth and health, enhancing nutrient availability and protecting plants from biotic and abiotic stresses. To assess bacterial diversity in the tomato rhizosphere, we performed two contrasting approaches: culture-dependent and -independent. In the culture-dependent approach, two culture media (Reasoner's 2A agar and soil extract agar) were supplemented with 12 antibiotics for isolating diverse bacteria from the tomato rhizosphere by inhibiting predominant bacteria.

Soil pH and electrical conductivity are key edaphic factors shaping bacterial communities of greenhouse soils in Korea.

Soil microorganisms play an essential role in soil ecosystem processes such as organic matter decomposition, nutrient cycling, and plant nutrient availability. The land use for greenhouse cultivation has been increasing continuously, which involves an intensive input of agricultural materials to enhance productivity; however, relatively little is known about bacterial communities in greenhouse soils. To assess the effects of environmental factors on the soil bacterial diversity and community composition, a total of 187 greenhouse soil samples collected across Korea were subjected to bacterial 16S rRNA gene pyrosequencing analysis.

Intrinsic Resistance of Burkholderia cepacia Complex to Benzalkonium Chloride.

Unlabelled: Pharmaceutical products that are contaminated with Burkholderia cepacia complex (BCC) bacteria may pose serious consequences to vulnerable patients. Benzyldimethylalkylammonium chloride (BZK) cationic surfactants are extensively used in medical applications and have been implicated in the coselection of antimicrobial resistance. The ability of BCC to degrade BZK, tetradecyldimethylbenzylammonium chloride (CBDMA-Cl), dodecyldimethylbenzylammonium chloride (CBDMA-Cl), decyldimethylbenzylammonium chloride (CBDMA-Cl), hexyldimethylbenzylammonium chloride, and benzyltrimethylammonium chloride was determined by incubation in 1/10-diluted tryptic soy broth (TSB) to determine if BCC bacteria have the ability to survive and inactivate these disinfectants.

Siphonobacter intestinalis sp. nov., a bacterium isolated from the feces of Pseudorhynchus japonicus.

Strain 63MJ-2 was isolated from the feces of broad-winged katydid (Pseudorhynchus japonicus) collected in Korea. The 16S rRNA gene sequence of this strain showed the highest sequence similarity with that of Siphonobacter aquaeclarae P2 (96.1%) and had low similarities (below 86.

Dynamics of bacterial communities in rice field soils as affected by different long-term fertilization practices.

Fertilization and the response of the soil microbial community to the process significantly affect crop yield and the environment. In this study, the seasonal variation in the bacterial communities in rice field soil subjected to different fertilization treatments for more than 50 years was investigated using 16S rRNA sequencing. The simultaneous application of inorganic fertilizers and rice straw compost (CAPK) maintained the species richness of the bacterial communities at levels higher than that in the case of non-fertilization (NF) and application of inorganic fertilizers only (APK) in the initial period of rice growth.

Survival and susceptibility of Burkholderia cepacia complex in chlorhexidine gluconate and benzalkonium chloride.

The Burkholderia cepacia complex (BCC) includes opportunistic pathogenic bacteria that have occasionally been recovered from various pharmaceutical products, including antiseptics and disinfectants. Plausible reasons for the contamination include intrinsic sources, such as inadequate process controls, especially for water or equipment used during product manufacture, or extrinsic sources, such as improper handling and dilution or distribution in contaminated containers. Because the survival of BCC in antiseptics is a concern to the public health and pharmaceutical industry, we determined minimum inhibitory concentrations (MICs) of 36 BCC strains against the antiseptics, following exposure to chlorhexidine gluconate (CHX) and benzalkonium chloride (BZK) solutions (1-500 µg/ml for each chemical).

Pleiotropic and epistatic behavior of a ring-hydroxylating oxygenase system in the polycyclic aromatic hydrocarbon metabolic network from Mycobacterium vanbaalenii PYR-1.

Despite the considerable knowledge of bacterial high-molecular-weight (HMW) polycyclic aromatic hydrocarbon (PAH) metabolism, the key enzyme(s) and its pleiotropic and epistatic behavior(s) responsible for low-molecular-weight (LMW) PAHs in HMW PAH-metabolic networks remain poorly understood. In this study, a phenotype-based strategy, coupled with a spray plate method, selected a Mycobacterium vanbaalenii PYR-1 mutant (6G11) that degrades HMW PAHs but not LMW PAHs. Sequence analysis determined that the mutant was defective in pdoA2, encoding an aromatic ring-hydroxylating oxygenase (RHO).

Evaluation of liquid and solid culture media for the recovery and enrichment of Burkholderia cenocepacia from distilled water.

Burkholderia cepacia complex (BCC) presence has been the cause of recalls of both sterile and non-sterile pharmaceutical products since these opportunistic pathogens have been implicated to cause infections to susceptible individuals. BCC are ubiquitous in nature, but in pharmaceutical settings the most common source is contaminated water systems. Some strains of BCC, previously described as Pseudomonas cepacia, were not readily detected by standard culture methods.

Aquamicrobium aestuarii sp. nov., a marine bacterium isolated from a tidal flat.

A Gram-negative, strictly aerobic, motile bacterium with flagella, designated strain G210(T), was isolated from a crude-oil-contaminated tidal flat of the Taean coast in South Korea. Cells were non-spore-forming, ovoid rods showing catalase- and oxidase-positive reactions. Growth of strain G210(T) was observed between 15 and 45 °C (optimum, 30-35 °C) and between pH 5.

Roseovarius lutimaris sp. nov., isolated from a marine tidal flat.

A novel Gram-staining-negative, moderately halophilic and strictly aerobic bacterium, designated strain 112(T), was isolated from a tidal flat at Taean, Korea. Cells were catalase- and oxidase-positive ovoids to rods and did not produce bacteriochlorophyll a. Optimum growth of strain 112(T) was observed at 30 °C, at pH 6.

Characterization of the denitrification-associated phosphorus uptake properties of "Candidatus Accumulibacter phosphatis" clades in sludge subjected to enhanced biological phosphorus removal.

To characterize the denitrifying phosphorus (P) uptake properties of "Candidatus Accumulibacter phosphatis," a sequencing batch reactor (SBR) was operated with acetate. The SBR operation was gradually acclimated from anaerobic-oxic (AO) to anaerobic-anoxic-oxic (A2O) conditions by stepwise increases of nitrate concentration and the anoxic time. The communities of "Ca.

Muricauda taeanensis sp. nov., isolated from a marine tidal flat.

A novel Gram-stain-negative, heterotrophic, moderate halophilic and strictly aerobic bacterium, strain 105(T), was isolated from a tidal flat of Taean in Korea. Cells were catalase- and oxidase-positive long rods that showed gliding motility. Optimum temperature, pH and salinity for the growth of strain 105(T) were observed at 30-37 °C, at pH 7.

Paenibacillus hordei sp. nov., isolated from naked barley in Korea.

A Gram-staining positive, facultative aerobic bacterium, designated strain RH-N24(T), was isolated from naked barley in South Korea. Cells of the isolate were observed to be motile rods by means of peritrichous flagella and showed catalase-positive and oxidase-negative reactions. Growth of strain RH-N24(T) was observed at 4-40 °C (optimum: 35-37 °C) and at pH 5.

Microbulbifer gwangyangensis sp. nov. and Microbulbifer pacificus sp. nov., isolated from marine environments.

Two novel Gram-stain-negative, chemoheterotrophic and strictly aerobic bacteria, strains GY2(T) and SPO729(T), were isolated from a tidal flat at Gwangyang Bay in Korea and a marine sponge sample from the Pacific Ocean, respectively. The two strains were halotolerant, catalase- and oxidase-positive, and non-motile rods. Optimum temperature and pH for growth of both strains were observed to be 35 °C and pH 7.

Alteromonas as a key agent of polycyclic aromatic hydrocarbon biodegradation in crude oil-contaminated coastal sediment.

Following the 2007 oil spill in South Korean tidal flats, we sought to identify microbial players influencing the environmental fate of released polycyclic aromatic hydrocarbons (PAHs). Two years of monitoring showed that PAH concentrations in sediments declined substantially. Enrichment cultures were established using seawater and modified minimal media containing naphthalene as sole carbon source.

Comparative genomics reveals adaptation by Alteromonas sp. SN2 to marine tidal-flat conditions: cold tolerance and aromatic hydrocarbon metabolism.

Alteromonas species are globally distributed copiotrophic bacteria in marine habitats. Among these, sea-tidal flats are distinctive: undergoing seasonal temperature and oxygen-tension changes, plus periodic exposure to petroleum hydrocarbons. Strain SN2 of the genus Alteromonas was isolated from hydrocarbon-contaminated sea-tidal flat sediment and has been shown to metabolize aromatic hydrocarbons there.

Arenibacter hampyeongensis sp. nov., a marine bacterium isolated from a tidal flat.

A Gram-staining-negative, dark orange, strictly aerobic bacterium, designated strain HP12(T), was isolated from a tidal flat at Hampyeong in South Korea. Cells were moderately halotolerant, catalase- and oxidase-positive, non-motile rods. Growth was observed at 5-35 °C (optimum, 25 °C), at pH 6.

Kordiimonas aestuarii sp. nov., a marine bacterium isolated from a tidal flat.

A Gram-staining negative, strictly aerobic bacterium, designated 101-1(T), was isolated from a sea tidal flat, Taean, Korea. The strain formed small light-yellow, smooth, and circular colonies on marine agar. Cells were weakly halophilic, motile rods showing catalase- and oxidase-positive reactions.