Bacterial diversity and predicted enzymatic function in a multipurpose surface water system - from wastewater effluent discharges to drinking water production.

Background: Rivers and lakes are used for multiple purposes such as for drinking water (DW) production, recreation, and as recipients of wastewater from various sources. The deterioration of surface water quality with wastewater is well-known, but less is known about the bacterial community dynamics in the affected surface waters. Understanding the bacterial community characteristics -from the source of contamination, through the watershed to the DW production process-may help safeguard human health and the environment.

Highlighting the promise of qPCR-based environmental monitoring: response of the ribosomal RNA:DNA ratio of calanoid copepods to toxic cyanobacteria.

Calanoid copepods are integral to aquatic food webs and may drive the bioaccumulation of toxins and heavy metals, spread of infectious diseases, and occurrence of toxic cyanobacterial harmful algal blooms (HABs) in freshwater aquatic systems. However, interrelationships between copepod and cyanobacterial population dynamics and ecophysiology remain unclear. Insights into these relationships are important to aquatic resource management, as they may help guide mitigation efforts.

Categorical performance characteristics of method ISO 7899-2 and indicator value of intestinal enterococci for bathing water quality monitoring.

Intestinal enterococci indicate the fecal contamination of bathing waters. This study defines the performance characteristics of the reference method ISO 7899-2:2000 with water samples collected from inland and coastal bathing areas in Finland. From a total of 341 bacterial isolates grown on Slanetz and Bartley medium, 63.

Corexit 9500 Enhances Oil Biodegradation and Changes Active Bacterial Community Structure of Oil-Enriched Microcosms.

To better understand the impacts of Corexit 9500 on the structure and activity levels of hydrocarbon-degrading microbial communities, we analyzed next-generation 16S rRNA gene sequencing libraries of hydrocarbon enrichments grown at 5 and 25°C using both DNA and RNA extracts as the sequencing templates. Oil biodegradation patterns in both 5 and 25°C enrichments were consistent with those reported in the literature (i.e.

Analysis of human mitochondrial DNA sequences from fecally polluted environmental waters as a tool to study population diversity.

Mitochondrial signature sequences have frequently been used to study human population diversity around the world. Traditionally, this requires obtaining samples directly from individuals which is cumbersome, time consuming and limited to the number of individuals that participated in these types of surveys. Here, we used environmental DNA extracts to determine the presence and sequence variability of human mitochondrial sequences as a means to study the diversity of populations inhabiting in areas nearby a tropical watershed impacted with human fecal pollution.

Biofilms on Hospital Shower Hoses: Characterization and Implications for Nosocomial Infections.

Although the source of drinking water (DW) used in hospitals is commonly disinfected, biofilms forming on water pipelines are a refuge for bacteria, including possible pathogens that survive different disinfection strategies. These biofilm communities are only beginning to be explored by culture-independent techniques that circumvent the limitations of conventional monitoring efforts. Hence, theories regarding the frequency of opportunistic pathogens in DW biofilms and how biofilm members withstand high doses of disinfectants and/or chlorine residuals in the water supply remain speculative.

Effects of Cr(III) and Cr(VI) on nitrification inhibition as determined by SOUR, function-specific gene expression and 16S rRNA sequence analysis of wastewater nitrifying enrichments.

The effect of Cr(III) and Cr(VI) on nitrification was examined with samples from nitrifying enrichment cultures using three different approaches: by measuring substrate (ammonia) specific oxygen uptake rates (SOUR), by using RT-qPCR to quantify the transcripts of functional genes involved in nitrification, and by analysis of 16S rRNA sequences to determine changes in structure and activity of the microbial communities. The nitrifying bioreactor was operated as a continuous reactor with a 24 h hydraulic retention time. The samples were exposed in batch vessels to Cr(III) (10-300 mg/L) and Cr(VI) (1-30 mg/L) for a period of 12 h.

Impact of Heavy Metals on Transcriptional and Physiological Activity of Nitrifying Bacteria.

Heavy metals can inhibit nitrification, a key process for nitrogen removal in wastewater treatment. The transcriptional responses of amoA, hao, nirK, and norB were measured in conjunction with specific oxygen uptake rate (sOUR) for nitrifying enrichment cultures exposed to different metals (Ni(II), Zn(II), Cd(II), and Pb(II)). There was significant decrease in sOUR with increasing concentrations for Ni(II) (0.

Distribution of human-specific bacteroidales and fecal indicator bacteria in an urban watershed impacted by sewage pollution, determined using RNA- and DNA-based quantitative PCR assays.

The identification of fecal pollution sources is commonly carried out using DNA-based methods. However, there is evidence that DNA can be associated with dead cells or present as "naked DNA" in the environment. Furthermore, it has been shown that rRNA-targeted reverse transcription-quantitative PCR (RT-qPCR) assays can be more sensitive than rRNA gene-based qPCR assays since metabolically active cells usually contain higher numbers of ribosomes than quiescent cells.

Intestinal microbiota and species diversity of Campylobacter and Helicobacter spp. in migrating shorebirds in Delaware Bay.

Using 16S rRNA gene sequencing analysis, we examined the bacterial diversity and the presence of opportunistic bacterial pathogens (i.e., Campylobacter and Helicobacter) in red knot (Calidris canutus; n = 40), ruddy turnstone (Arenaria interpres; n = 35), and semipalmated sandpiper (Calidris pusilla; n = 22) fecal samples collected during a migratory stopover in Delaware Bay.

Detection of fecal bacteria and source tracking identifiers in environmental waters using rRNA-based RT-qPCR and rDNA-based qPCR assays.

In this study, we evaluated the use of RT-qPCR assays targeting rRNA gene sequences for the detection of fecal bacteria in water samples. We challenged the RT-qPCR assays against RNA extracted from sewage effluent (n = 14), surface water (n = 30), and treated source water (n = 15) samples. Additionally, we applied the same assays using DNA as the qPCR template.

Comparison of two poultry litter qPCR assays targeting the 16S rRNA gene of Brevibacterium sp.

Chicken feces commonly contain human pathogens and are also important sources of fecal pollution in environmental waters. Consequently, methods that can detect chicken fecal pollution are needed in public health and environmental monitoring studies. In this study, we compared a previously developed SYBR green qPCR assay (LA35) to a novel TaqMan qPCR assay (CL) for the environmental detection of poultry-associated fecal pollution.

The impact of silver nanoparticles on the composting of municipal solid waste.

The study evaluates the impact of polyvinylpyrrolidone (PVP) coated silver nanoparticles (PVP-AgNPs) on the composting of municipal solid waste. The results suggest that there was no statistically significant difference in the leachate, gas, and solid quality parameters and overall composting performance between the treatments containing the AgNPs, Ag(+), and negative control. Nonetheless, taxonomical analyses of 25 Illumina 16S rDNA barcoded libraries containing 2 393 504 sequences indicated that the bacterial communities in composted samples were highly diverse and primarily dominated by Clostridia (48.

Development of quantitative PCR assays targeting the 16S rRNA genes of Enterococcus spp. and their application to the identification of enterococcus species in environmental samples.

The detection of environmental enterococci has been determined primarily by using culture-based techniques that might exclude some enterococcal species as well as those that are nonculturable. To address this, the relative abundances of enterococci were examined by challenging fecal and water samples against a currently available genus-specific assay (Entero1). To determine the diversity of enterococcal species, 16S rRNA gene-based group-specific quantitative PCR (qPCR) assays were developed and evaluated against eight of the most common environmental enterococcal species.

Development and evaluation of a quantitative PCR assay targeting sandhill crane (Grus canadensis) fecal pollution.

While the microbial water quality in the Platte River is seasonally impacted by excreta from migrating cranes, there are no methods available to study crane fecal contamination. Here we characterized microbial populations in crane feces using phylogenetic analysis of 16S rRNA gene fecal clone libraries. Using these sequences, a novel crane quantitative PCR (Crane1) assay was developed, and its applicability as a microbial source tracking (MST) assay was evaluated by determining its host specificity and detection ability in environmental waters.