Application of microwaves for microbial load reduction in black pepper (Piper nigrum L.).

PubMed

Jeevitha, G Chengaiyan; Sowbhagya, H Bogegowda; Hebbar, H Umesh

2016-09-01

Black pepper (Piper nigrum L.) is exposed to microbial contamination which could potentially create public health risk and also rejection of consignments in the export market due to non-adherance to microbial safety standards. The present study investigates the use of microwave (MW) radiation for microbial load reduction in black pepper and analyses the effect on quality. Black pepper was exposed to MWs at two different power levels (663 and 800 W) at an intensity of 40 W g(-1) for different time intervals (1-15 min) and moisture content (110 and 260 g kg(-1) on a wet basis). The exposure of black pepper to MWs at 663 W for 12.5 min was found to be sufficient to reduce the microbial load to the permissible level suggested by the International Commission on Microbiological Specifications for Foods and the European Spice Association. The retention of volatile oil, piperine and resin was 91.3 ± 0.03, 87.6 ± 0.02 and 90.7 ± 0.05%, respectively, in MW-treated black pepper. The final moisture content after MW treatment was found to be 100 ± 1 g kg(-1) for black pepper containing initial moisture of 260 ± 3 g kg(-1) . These results suggest that MW heating can be effectively used for microbial load reduction of black pepper without a significant loss in product quality. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Microbial loads and antibiotic resistance patterns of Staphylococcus aureus in different types of raw poultry-based meat preparations.

PubMed

Buzón-Durán, Laura; Capita, Rosa; Alonso-Calleja, Carlos

2017-09-01

The hygiene status of raw chicken-meat preparations from retail outlets in North-Western Spain was investigated. Microbial counts (aerobic plate counts (APCs), psychrotrophs, Enterobacteriaceae, fecal coliforms, enterococci, pseudomonads, fluorescent pseudomonads, yeasts and molds, and Staphylococcus aureus) were determined for minced meat, hamburgers, nuggets, white sausages, red sausages, escalope, and roll-ups. S. aureus isolates were tested for susceptibility to twenty antimicrobials of veterinary and human clinical significance (disc diffusion method, CLSI). Average microbial loads (log10 cfu/g) ranged from 2.63 ± 0.80 (enterococci) to 6.66 ± 1.09 (psychrotrophs). Average APCs (6.44 ± 1.16 log10 cfu/g) were regarded as acceptable according to EU microbiological criteria. The type of product had an influence (P < 0.05) on microbial loads, samples of escalope showing the highest counts for most microbial groups. Two-thirds (66.7%) of the samples tested harbored S. aureus. All the S. aureus isolates were multi-resistant (to between three and fifteen antibiotics). The greatest prevalence of resistance was shown for ampicillin, oxacillin, penicillin G, ceftazidime, and nalidixic acid. The results of this study show that poultry-based meat preparations present high microbial loads and are a major reservoir of antibiotic-resistant S. aureus strains. This highlights the need for correct handling of such foodstuffs with a view to reducing risks to consumers. © 2017 Poultry Science Association Inc.

Genome-Resolved Meta-Omics Ties Microbial Dynamics to Process Performance in Biotechnology for Thiocyanate Degradation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kantor, Rose S.; Huddy, Robert J.; Iyer, Ramsunder

Remediation of industrial wastewater is important for preventing environmental contamination and allowing water reuse. Biological treatment for one industrial contaminant, thiocyanate (SCN - ), relies upon microbial hydrolysis, but this process is sensitive to high loadings. To examine the activity and stability of a microbial community over increasing SCN - loadings, we established and operated a continuous-flow bioreactor fed increasing loadings of SCN - . A second reactor was fed ammonium sulfate to mimic breakdown products of SCN - . Biomass was sampled from both reactors for metagenomics and metaproteomics, yielding a set of genomes for 144 bacteria and onemore » rotifer that constituted the abundant community in both reactors. We analyzed the metabolic potential and temporal dynamics of these organisms across the increasing loadings. In the SCN - reactor, Thiobacillus strains capable of SCN - degradation were highly abundant, whereas the ammonium sulfate reactor contained nitrifiers and heterotrophs capable of nitrate reduction. Key organisms in the SCN - reactor expressed proteins involved in SCN - degradation, sulfur oxidation, carbon fixation, and nitrogen removal. Lower performance at higher loadings was linked to changes in microbial community composition. This work provides an example of how meta-omics can increase our understanding of industrial wastewater treatment and inform iterative process design and development.« less

Long-range transport of airborne microbes over the global tropical and subtropical ocean.

PubMed

Mayol, Eva; Arrieta, Jesús M; Jiménez, Maria A; Martínez-Asensio, Adrián; Garcias-Bonet, Neus; Dachs, Jordi; González-Gaya, Belén; Royer, Sarah-J; Benítez-Barrios, Verónica M; Fraile-Nuez, Eugenio; Duarte, Carlos M

2017-08-04

The atmosphere plays a fundamental role in the transport of microbes across the planet but it is often neglected as a microbial habitat. Although the ocean represents two thirds of the Earth's surface, there is little information on the atmospheric microbial load over the open ocean. Here we provide a global estimate of microbial loads and air-sea exchanges over the tropical and subtropical oceans based on the data collected along the Malaspina 2010 Circumnavigation Expedition. Total loads of airborne prokaryotes and eukaryotes were estimated at 2.2 × 10 21 and 2.1 × 10 21 cells, respectively. Overall 33-68% of these microorganisms could be traced to a marine origin, being transported thousands of kilometres before re-entering the ocean. Moreover, our results show a substantial load of terrestrial microbes transported over the oceans, with abundances declining exponentially with distance from land and indicate that islands may act as stepping stones facilitating the transoceanic transport of terrestrial microbes.The extent to which the ocean acts as a sink and source of airborne particles to the atmosphere is unresolved. Here, the authors report high microbial loads over the tropical Atlantic, Pacific and Indian oceans and propose islands as stepping stones for the transoceanic transport of terrestrial microbes..

Genome-Resolved Meta-Omics Ties Microbial Dynamics to Process Performance in Biotechnology for Thiocyanate Degradation

DOE PAGES

Kantor, Rose S.; Huddy, Robert J.; Iyer, Ramsunder; ...

2017-01-31

Remediation of industrial wastewater is important for preventing environmental contamination and allowing water reuse. Biological treatment for one industrial contaminant, thiocyanate (SCN - ), relies upon microbial hydrolysis, but this process is sensitive to high loadings. To examine the activity and stability of a microbial community over increasing SCN - loadings, we established and operated a continuous-flow bioreactor fed increasing loadings of SCN - . A second reactor was fed ammonium sulfate to mimic breakdown products of SCN - . Biomass was sampled from both reactors for metagenomics and metaproteomics, yielding a set of genomes for 144 bacteria and onemore » rotifer that constituted the abundant community in both reactors. We analyzed the metabolic potential and temporal dynamics of these organisms across the increasing loadings. In the SCN - reactor, Thiobacillus strains capable of SCN - degradation were highly abundant, whereas the ammonium sulfate reactor contained nitrifiers and heterotrophs capable of nitrate reduction. Key organisms in the SCN - reactor expressed proteins involved in SCN - degradation, sulfur oxidation, carbon fixation, and nitrogen removal. Lower performance at higher loadings was linked to changes in microbial community composition. This work provides an example of how meta-omics can increase our understanding of industrial wastewater treatment and inform iterative process design and development.« less

Effect of high hydrostatic pressure processing on the background microbial loads and quality of cantaloupe puree

USDA-ARS?s Scientific Manuscript database

The objective of this study was to investigate and evaluate the effects of high hydrostatic pressure (HHP) applied to cantaloupe puree (CP) on microbial loads and product quality during storage for 10 days at 4 degrees C. Freshly prepared, double sealed and double bagged CP (ca. 5 g) was pressure tr...

Potential microbial risk factors related to soil amendments and irrigation water of potato crops.

PubMed

Selma, M V; Allende, A; López-Gálvez, F; Elizaquível, P; Aznar, R; Gil, M I

2007-12-01

This study assesses the potential microbial risk factors related to the use of soil amendments and irrigation water on potato crops, cultivated in one traditional and two intensive farms during two harvest seasons. The natural microbiota and potentially pathogenic micro-organisms were evaluated in the soil amendment, irrigation water, soil and produce. Uncomposted amendments and residual and creek water samples showed the highest microbial counts. The microbial load of potatoes harvested in spring was similar among the tested farms despite the diverse microbial levels of Listeria spp. and faecal coliforms in the potential risk sources. However, differences in total coliform load of potato were found between farms cultivated in the autumn. Immunochromatographic rapid tests and the BAM's reference method (Bacteriological Analytical Manual; AOAC International) were used to detect Escherichia coli O157:H7 from the potential risk sources and produce. Confirmation of the positive results by polymerase chain reaction procedures showed that the immunochromatographic assay was not reliable as it led to false-positive results. The potentially pathogenic micro-organisms of soil amendment, irrigation water and soil samples changed with the harvest seasons and the use of different agricultural practices. However, the microbial load of the produce was not always influenced by these risk sources. Improvements in environmental sample preparation are needed to avoid interferences in the use of immunochromatographic rapid tests. The potential microbial risk sources of fresh produce should be regularly controlled using reliable detection methods to guarantee their microbial safety.

Effect of UV-C treatment on inactivation of Escherichia coli O157:H7, microbial loads, and quality of button mushrooms

USDA-ARS?s Scientific Manuscript database

This study investigated the effects of ultraviolet-C (UV-C) light applied to both sides of mushrooms on microbial loads and product quality during storage for 21 days at 4 C. Microflora populations, color, antioxidant activity, total phenolics, and ascorbic acid were measured at 1, 7, 14 and 21 days...

Validated measurements of microbial loads on environmental surfaces in intensive care units before and after disinfecting cleaning.

PubMed

Frickmann, H; Bachert, S; Warnke, P; Podbielski, A

2018-03-01

Preanalytic aspects can make results of hygiene studies difficult to compare. Efficacy of surface disinfection was assessed with an evaluated swabbing procedure. A validated microbial screening of surfaces was performed in the patients' environment and from hands of healthcare workers on two intensive care units (ICUs) prior to and after a standardized disinfection procedure. From a pure culture, the recovery rate of the swabs for Staphylococcus aureus was 35%-64% and dropped to 0%-22% from a mixed culture with 10-times more Staphylococcus epidermidis than S. aureus. Microbial surface loads 30 min before and after the cleaning procedures were indistinguishable. The quality-ensured screening procedure proved that adequate hygiene procedures are associated with a low overall colonization of surfaces and skin of healthcare workers. Unchanged microbial loads before and after surface disinfection demonstrated the low additional impact of this procedure in the endemic situation when the pathogen load prior to surface disinfection is already low. Based on a validated screening system ensuring the interpretability and reliability of the results, the study confirms the efficiency of combined hand and surface hygiene procedures to guarantee low rates of bacterial colonization. © 2017 The Society for Applied Microbiology.

MICROBIAL ENZYME ACTIVITY FOR CHARACTERIZING NUTRIENT LOADING TO GREAT LAKES COASTAL WETLANDS

EPA Science Inventory

Energy and material flows in aquatic ecosystems are mediated by microbial carbon and nutrient cycling. Extracellular enzymes produced by the microbial community aid in the degradation of organic matter and the resultant acquisition of limiting nutrients. Organic carbon sequestrat...

Relationships between processing delay and microbial load of broiler neck skin samples.

PubMed

Lucianez, A; Holmes, M A; Tucker, A W

2010-01-01

The measurable microbial load on poultry carcasses during processing is determined by a number of factors including farm or origin, processing hygiene, and external temperature. This study investigated associations between carcass microbial load and progressive delays to processing. A total of 30 carcasses were delayed immediately after defeathering and before evisceration in a commercial abattoir in groups of five, and were held at ambient temperature for 1, 2, 3, 4, 6, and 8 h. Delayed carcasses were reintroduced to the processing line, and quantitative assessment of total viable count, coliforms, Staphylococcus aureus, and Pseudomonas spp. was undertaken on neck skin flap samples collected after carcass chilling and then pooled for each group. Sampling was repeated on 5 separate days, and the data were combined. Significant increases in total viable count (P = 0.001) and coliforms (P = 0.004), but not for S. aureus or Pseudomonas loads, were observed across the 8-h period of delay. In line with previous studies, there was significant variation in microbiological data according to sampling day. In conclusion, there is a significant and measurable decline in microbiological status of uneviscerated but defeathered poultry carcasses after an 8-h delay, but the variability of sampling results, reflecting the wide range of factors that impact microbial load, means that it is not possible to determine maximum or minimum acceptable periods of processing delay based on this criterion alone.

Microbial enhancement of compost extracts based on cattle rumen content compost - characterisation of a system.

PubMed

Shrestha, Karuna; Shrestha, Pramod; Walsh, Kerry B; Harrower, Keith M; Midmore, David J

2011-09-01

Microbially enhanced compost extracts ('compost tea') are being used in commercial agriculture as a source of nutrients and for their perceived benefit to soil microbiology, including plant disease suppression. Rumen content material is a waste of cattle abattoirs, which can be value-added by conversion to compost and 'compost tea'. A system for compost extraction and microbial enhancement was characterised. Molasses amendment increased bacterial count 10-fold, while amendment based on molasses and 'fish and kelp hydrolysate' increased fungal count 10-fold. Compost extract incubated at 1:10 (w/v) dilution showed the highest microbial load, activity and humic/fulvic acid content compared to other dilutions. Aeration increased the extraction efficiency of soluble metabolites, and microbial growth rate, as did extraction of compost without the use of a constraining bag. A protocol of 1:10 dilution and aerated incubation with kelp and molasses amendments is recommended to optimise microbial load and fungal-to-bacterial ratio for this inoculum source. Copyright © 2011 Elsevier Ltd. All rights reserved.

Effect of gamma irradiation under various atmospheres of packaging on the microbial and physicochemical properties of turmeric powder

NASA Astrophysics Data System (ADS)

Esmaeili, Saeideh; Barzegar, Mohsen; Sahari, Mohammad Ali; Berengi-Ardestani, Samira

2018-07-01

This study investigated the effect of gamma irradiation (0, 5, 10, and 15 kGy) under various atmospheres of packaging (air, N₂, and vacuum) on the microbial load and physicochemical properties of turmeric powder, including antioxidant activities, total phenolic content (TPC), color parameters, and curcuminoid content. The efficiency of irradiation in reducing microbial contamination in the samples was observed even at the lowest dose. By increasing the irradiation dose, the microbial load was not detectable. Irradiation in the presence of oxygen had synergistic effects on the extraction of curcuminoids and TPC, and increased the antioxidant activity of the methanolic extracts: highest activity was observed at 15 kGy. Generally, gamma irradiation up to the dose of 10 kGy under air atmosphere not only ensured microbial safety and desirability of turmeric powder, but also improved the extraction yield of bioactive compounds and, consequently, antioxidant activities of the samples.

Rapid and quantitative detection of the microbial spoilage in chicken meat by diffuse reflectance spectroscopy (600-1100 nm).

PubMed

Lin, M; Al-Holy, M; Mousavi-Hesary, M; Al-Qadiri, H; Cavinato, A G; Rasco, B A

2004-01-01

To evaluate the feasibility of visible and short-wavelength near-infrared (SW-NIR) diffuse reflectance spectroscopy (600-1100 nm) to quantify the microbial loads in chicken meat and to develop a rapid methodology for monitoring the onset of spoilage. Twenty-four prepackaged fresh chicken breast muscle samples were prepared and stored at 21 degrees C for 24 h. Visible and SW-NIR was used to detect and quantify the microbial loads in chicken breast muscle at time intervals of 0, 2, 4, 6, 8, 10, 12 and 24 h. Spectra were collected in the diffuse reflectance mode (600-1100 nm). Total aerobic plate count (APC) of each sample was determined by the spread plate method at 32 degrees C for 48 h. Principal component analysis (PCA) and partial least squares (PLS) based prediction models were developed. PCA analysis showed clear segregation of samples held 8 h or longer compared with 0-h control. An optimum PLS model required eight latent variables for chicken muscle (R = 0.91, SEP = 0.48 log CFU g(-1)). Visible and SW-NIR combined with PCA is capable of perceiving the change of the microbial loads in chicken muscle once the APC increases slightly above 1 log cycle. Accurate quantification of the bacterial loads in chicken muscle can be calculated from the PLS-based prediction method. Visible and SW-NIR spectroscopy is a technique with a considerable potential for monitoring food safety and food spoilage. Visible and SW-NIR can acquire a metabolic snapshot and quantify the microbial loads of food samples rapidly, accurately, and noninvasively. This method would allow for more expeditious applications of quality control in food industries.

Microbial Source Module (MSM): Documenting the Science and Software for Discovery, Evaluation, and Integration

EPA Science Inventory

The Microbial Source Module (MSM) estimates microbial loading rates to land surfaces from non-point sources, and to streams from point sources for each subwatershed within a watershed. A subwatershed, the smallest modeling unit, represents the common basis for information consume...

Wound Bioburden and Infection-Related Complications in Diabetic Foot Ulcers

PubMed Central

Gardner, Sue E.; Frantz, Rita A.

2013-01-01

The identification and diagnosis of diabetic foot ulcer (DFU) infections remains a complex problem. Because inflammatory responses to microbial invasion may be diminished in persons with diabetes, clinical signs of infection are often absent in persons with DFUs when infection is limited to localized tissue. In the absence of these clinical signs, microbial load is believed to be the best indicator of infection. Some researchers, however, believe microbial load to be insignificant and type of organism growing in the ulcer to be most important. Previous studies on the microbiology of DFUs have not provided enough evidence to determine the microbiological parameters of importance. Infection-related complications of DFUs include wound deterioration, osteomyelitis, and amputation. Risk factors for amputation include age, peripheral vascular disease, low transcutaneous oxygen, smoking, and poor glycemic control. These risk factors are best measured directly with physiological measures of arterial perfusion, glycemic control, sensory neuropathy, plantar pressures, and activity level and by controlling off-loading. DFU bioburden has not been examined as a risk factor for infection-related complications. To address the relationship between wound bioburden and the development of infection-related complications in DFUs, tightly controlled prospective studies based on clearly defined, valid measures of wound bioburden and wound outcomes are needed. This article reviews the literature and proposes a model of hypothesized relationships between wound bioburden—including microbial load, microbial diversity, and pathogenicity of organisms—and the development of infection-related complications. PMID:18647759

Monitoring of Microbial Loads During Long Duration Missions as a Risk Reduction Tool

NASA Technical Reports Server (NTRS)

Roman, Monsi C.

2011-01-01

Humans have been exploring space for more than 40 years. For all those years microorganisms have accompanied, first un-manned spacecraft/cargo and later manned vessels. Microorganisms are everywhere on Earth, could easily adapt to new environments and/or can rapidly mutate to survive in very harsh conditions. Their presence in spacecraft and cargo have caused a few inconveniences over the years of humans spaceflight, ranging from crew health, life support systems challenges and material degradation. The sterilization of spacecraft that will host humans in long duration mission would be a costly operation that will not provide a long-term solution to the microbial colonization of the vessels. As soon as a human is exposed to the spacecraft, during the mission, microorganisms will start to populate the new environment. As the hum an presence in space increases in length, the risk from the microbial load, to hardware and crew will also increase. Mitigation of this risk includes several different strategies that will include minimizing the microbial load (in numbers and diversity) and monitoring. This presentation will provide a list of the risk mitigation strategies that should be implemented during ground processing, and during the mission. It will also discuss the areas that should be discussed before an effective in-flight microbial monitoring regimen is implemented. Microbial monitoring technologies will also be presented.

Microbial load monitor

NASA Technical Reports Server (NTRS)

Caplin, R. S.; Royer, E. R.

1978-01-01

Attempts are made to provide a total design of a Microbial Load Monitor (MLM) system flight engineering model. Activities include assembly and testing of Sample Receiving and Card Loading Devices (SRCLDs), operator related software, and testing of biological samples in the MLM. Progress was made in assembling SRCLDs with minimal leaks and which operate reliably in the Sample Loading System. Seven operator commands are used to control various aspects of the MLM such as calibrating and reading the incubating reading head, setting the clock and reading time, and status of Card. Testing of the instrument, both in hardware and biologically, was performed. Hardware testing concentrated on SRCLDs. Biological testing covered 66 clinical and seeded samples. Tentative thresholds were set and media performance listed.

A comparison of additional treatment processes to limit particle accumulation and microbial growth during drinking water distribution.

PubMed

Liu, G; Lut, M C; Verberk, J Q J C; Van Dijk, J C

2013-05-15

Water quality changes, particle accumulation and microbial growth occurring in pilot-scale water distribution systems fed with normally treated and additional treated groundwater were monitored over a period of almost one year. The treatment processes were ranked in the following order: nanofiltration (NF) > (better than) ultrafiltration (UF) > ion exchange (IEX) for limiting particle accumulation. A different order was found for limiting overall microbial growth: NF > IEX > UF. There were strong correlations between particle load and particle accumulation, and between nutrient load and microbial growth. It was concluded that particle accumulation can be controlled by reducing the particle load in water treatment plants; and the microbial growth can be better controlled by limiting organic nutrients rather than removing biomass in water treatment plants. The major focus of this study was on microbial growth. The results demonstrated that growth occurred in all types of treated water, including the phases of bulk water, biofilm and loose deposits. Considering the growth in different phases, similar growth in bulk water was observed for all treatments; NF strongly reduced growth both in loose deposits and in biofilm; UF promoted growth in biofilm, while strongly limiting growth in loose deposits. IEX had good efficiency in between UF and NF, limiting both growths in loose deposits and in biofilm. Significant growth was found in loose deposits, suggesting that loose deposit biomass should be taken into account for growth evaluation and/or prediction. Strong correlations were found between microbial growth and pressure drop in a membrane fouling simulator which proved that a membrane fouling simulator can be a fast growth predictor (within a week). Different results obtained by adenosine triphosphate and flow cytometry cell counts revealed that ATP can accurately describe both suspended and particle-associated biomass, and flow cytometry files of TCC measurements needs to be further processed for particle loaded samples and/or a pretreatment protocol should be developed. Copyright © 2013 Elsevier Ltd. All rights reserved.

Biodegradation of Methyl Tertiary Butyl Ether (MTBE) by a Microbial Consortium in a Continuous Up-Flow Packed-Bed Biofilm Reactor: Kinetic Study, Metabolite Identification and Toxicity Bioassays

PubMed Central

Alfonso-Gordillo, Guadalupe; Flores-Ortiz, César Mateo; Morales-Barrera, Liliana

2016-01-01

This study investigated the aerobic biodegradation of methyl tertiary-butyl ether (MTBE) by a microbial consortium in a continuous up-flow packed-bed biofilm reactor using tezontle stone particles as a supporting material for the biofilm. Although MTBE is toxic for microbial communities, the microbial consortium used here was able to resist MTBE loading rates up to 128.3 mg L-1 h-1, with removal efficiencies of MTBE and chemical oxygen demand (COD) higher than 90%. A linear relationship was observed between the MTBE loading rate and the MTBE removal rate, as well as between the COD loading rate and the COD removal rate, within the interval of MTBE loading rates from 11.98 to 183.71 mg L-1 h-1. The metabolic intermediate tertiary butyl alcohol (TBA) was not detected in the effluent during all reactor runs, and the intermediate 2-hydroxy butyric acid (2-HIBA) was only detected at MTBE loading rates higher than 128.3 mg L-1 h-1. The results of toxicity bioassays with organisms from two different trophic levels revealed that the toxicity of the influent was significantly reduced after treatment in the packed-bed reactor. The packed-bed reactor system used in this study was highly effective for the continuous biodegradation of MTBE and is therefore a promising alternative for detoxifying MTBE-laden wastewater and groundwater. PMID:27907122

Biodegradation of Methyl Tertiary Butyl Ether (MTBE) by a Microbial Consortium in a Continuous Up-Flow Packed-Bed Biofilm Reactor: Kinetic Study, Metabolite Identification and Toxicity Bioassays.

PubMed

Alfonso-Gordillo, Guadalupe; Flores-Ortiz, César Mateo; Morales-Barrera, Liliana; Cristiani-Urbina, Eliseo

2016-01-01

This study investigated the aerobic biodegradation of methyl tertiary-butyl ether (MTBE) by a microbial consortium in a continuous up-flow packed-bed biofilm reactor using tezontle stone particles as a supporting material for the biofilm. Although MTBE is toxic for microbial communities, the microbial consortium used here was able to resist MTBE loading rates up to 128.3 mg L-1 h-1, with removal efficiencies of MTBE and chemical oxygen demand (COD) higher than 90%. A linear relationship was observed between the MTBE loading rate and the MTBE removal rate, as well as between the COD loading rate and the COD removal rate, within the interval of MTBE loading rates from 11.98 to 183.71 mg L-1 h-1. The metabolic intermediate tertiary butyl alcohol (TBA) was not detected in the effluent during all reactor runs, and the intermediate 2-hydroxy butyric acid (2-HIBA) was only detected at MTBE loading rates higher than 128.3 mg L-1 h-1. The results of toxicity bioassays with organisms from two different trophic levels revealed that the toxicity of the influent was significantly reduced after treatment in the packed-bed reactor. The packed-bed reactor system used in this study was highly effective for the continuous biodegradation of MTBE and is therefore a promising alternative for detoxifying MTBE-laden wastewater and groundwater.

Antimicrobial drugs encapsulated in fibrin nanoparticles for treating microbial infested wounds.

PubMed

Alphonsa, B Maria; Sudheesh Kumar, P T; Praveen, G; Biswas, Raja; Chennazhi, K P; Jayakumar, R

2014-05-01

In vitro evaluation of antibacterial and antifungal drugs encapsulated fibrin nanoparticles to prove their potential prospect of using these nanocomponent for effective treatment of microbial infested wounds. Surfactant-free oil-in-water emulsification-diffusion method was adopted to encapsulate 1 mg/ml each of antimicrobial drugs (Ciprofloxacin and Fluconazole) in 4 ml of aqueous fibrinogen suspension and subsequent thrombin mediated cross linking to synthesize drug loaded fibrin nanoparticles. Ciprofloxacin loaded fibrin nanoparticles (CFNPs) showed size range of 253 ± 6 nm whereas that of Fluconazole loaded fibrin nanoparticles (FFNPs) was 260 ± 10 nm. Physico chemical characterizations revealed the firm integration of antimicrobial drugs within fibrin nanoparticles. Drug release studies performed at physiological pH 7.4 showed a release of 16% ciprofloxacin and 8% of fluconazole while as the release of ciprofloxacin at alkaline pH 8.5, was 48% and that of fluconazole was 37%. The antimicrobial activity evaluations of both drug loaded systems independently showed good antibacterial activity against Escherichia coli (E.coli), Staphylococcus aureus (S. aureus) and antifungal activity against Candida albicans (C. albicans). The in vitro toxicity of the prepared drug loaded nanoparticles were further analyzed using Human dermal fibroblast cells (HDF) and showed adequate cell viability. The efficacies of both CFNPs and FFNPs for sustained delivery of encapsulated anti microbial drugs were evaluated in vitro suggesting its potential use for treating microbial infested wounds (diabetic foot ulcer).

Microbial Load Monitor

NASA Technical Reports Server (NTRS)

Gibson, S. F.; Royer, E. R.

1979-01-01

The Microbial Load Monitor (MLM) is an automated and computerized system for detection and identification of microorganisms. Additionally, the system is designed to enumerate and provide antimicrobic susceptibility profiles for medically significant bacteria. The system is designed to accomplish these tasks in a time of 13 hours or less versus the traditional time of 24 hours for negatives and 72 hours or more for positives usually required for standard microbiological analysis. The MLM concept differs from other methods of microbial detection in that the system is designed to accept raw untreated clinical samples and to selectively identify each group or species that may be present in a polymicrobic sample.

Catalase measurement: A new field procedure for rapidly estimating microbial loads in fuels and water-bottoms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Passman, F.J.; Daniels, D.A.; Chesneau, H.F.

1995-05-01

Low-grade microbial infections of fuel and fuel systems generally go undetected until they cause major operational problems. Three interdependent factors contribute to this: mis-diagnosis, incorrect or inadequate sampling procedures and perceived complexity of microbiological testing procedures. After discussing the first two issues, this paper describes a rapid field test for estimating microbial loads in fuels and associated water. The test, adapted from a procedure initially developed to measure microbial loads in metalworking fluids, takes advantage of the nearly universal presence of the enzyme catalase in the microbes that contaminated fuel systems. Samples are reacted with a peroxide-based reagent; liberating oxygenmore » gas. The gas generates a pressure-head in a reaction tube. At fifteen minutes, a patented, electronic pressure-sensing device is used to measure that head-space pressure. The authors present both laboratory and field data from fuels and water-bottoms, demonstrating the excellent correlation between traditional viable test data (acquired after 48-72 hours incubation) and catalase test data (acquired after 15 min.-4 hours). We conclude by recommending procedures for developing a failure analysis data-base to enhance our industry`s understanding of the relationship between uncontrolled microbial contamination and fuel performance problems.« less

Monitoring of Microbial Loads During Long Duration Missions as a Risk Reduction Tool

NASA Astrophysics Data System (ADS)

Roman, M. C.; Mena, K. D.

2012-01-01

Humans have been exploring space for more than 40 years. For all those years, microorganisms have accompanied both un-manned spacecraft/cargo and manned vessels. Microorganisms are everywhere on Earth, could easily adapt to new environments, and/or can rapidly mutate to survive in very harsh conditions. Their presence in spacecraft and cargo have caused a few inconveniences over the years of human spaceflight, ranging from crew health, life support systems challenges, and material degradation. The sterilization of spacecraft that will host humans in long duration mission would be a costly operation that will not provide a long-term solution to the microbial colonization of the vessels. As soon as a human is exposed to the spacecraft, microorganisms start populating the new environment during the mission. As the human presence in space increases in length, the risk from the microbial load to hardware and crew will also increase. Mitigation of this risk involves several different strategies that will include minimizing the microbial load (in numbers and diversity) and monitoring. This paper will provide a list of the risk mitigation strategies that should be implemented during ground processing, and during the mission. It will also discuss the areas that should be reviewed before an effective in-flight microbial monitoring regimen is implemented.

A first study comparing preservation of a ready-to-eat soup under pressure (hyperbaric storage) at 25°C and 30°C with refrigeration.

PubMed

Moreira, Sílvia A; Fernandes, Pedro A R; Duarte, Ricardo; Santos, Diana I; Fidalgo, Liliana G; Santos, Mauro D; Queirós, Rui P; Delgadillo, Ivonne; Saraiva, Jorge A

2015-11-01

Hyperbaric storage (HS), storage under pressure at 25°C and 30°C, of a ready-to-eat (RTE) soup was studied and compared with refrigeration. Soup was stored at different time (4 and 8 h), temperature (4°C, 25°C, and 30°C), and pressure (0.1, 100, and 150 MPa) conditions, to compare microbial loads and physicochemical parameters. HS resulted in similar (microbial growth inhibition) to better (microbial inactivation) results compared to refrigeration, leading to equal and lower microbial loads, respectively, at the end of storage. Lower/higher pressure (100 vs. 150 MPa) and shorter/longer storage times (4 vs. 8 h) resulted in more pronounced microbial growth inhibition/microbial inactivation. Aerobic mesophiles showed less susceptibility to HS, compared to Enterobacteriaceae and yeast and molds. HS maintained generally the physicochemical parameters at values similar to refrigeration. Thus, HS with no need for temperature control throughout storage and so basically energetically costless, is a potential alternative to refrigeration.

Short-term effect of antibiotics on human gut microbiota.

PubMed

Panda, Suchita; El khader, Ismail; Casellas, Francesc; López Vivancos, Josefa; García Cors, Montserrat; Santiago, Alba; Cuenca, Silvia; Guarner, Francisco; Manichanh, Chaysavanh

2014-01-01

From birth onwards, the human gut microbiota rapidly increases in diversity and reaches an adult-like stage at three years of age. After this age, the composition may fluctuate in response to external factors such as antibiotics. Previous studies have shown that resilience is not complete months after cessation of the antibiotic intake. However, little is known about the short-term effects of antibiotic intake on the gut microbial community. Here we examined the load and composition of the fecal microbiota immediately after treatment in 21 patients, who received broad-spectrum antibiotics such as fluoroquinolones and β-lactams. A fecal sample was collected from all participants before treatment and one week after for microbial load and community composition analyses by quantitative PCR and pyrosequencing of the 16S rRNA gene, respectively. Fluoroquinolones and β-lactams significantly decreased microbial diversity by 25% and reduced the core phylogenetic microbiota from 29 to 12 taxa. However, at the phylum level, these antibiotics increased the Bacteroidetes/Firmicutes ratio (p = 0.0007, FDR = 0.002). At the species level, our findings unexpectedly revealed that both antibiotic types increased the proportion of several unknown taxa belonging to the Bacteroides genus, a Gram-negative group of bacteria (p = 0.0003, FDR<0.016). Furthermore, the average microbial load was affected by the treatment. Indeed, the β-lactams increased it significantly by two-fold (p = 0.04). The maintenance of or possible increase detected in microbial load and the selection of Gram-negative over Gram-positive bacteria breaks the idea generally held about the effect of broad-spectrum antibiotics on gut microbiota.

Nitrogen enrichment suppresses other environmental drivers and homogenizes salt marsh leaf microbiome

DOE PAGES

Daleo, Pedro; Alberti, Juan; Jumpponen, Ari; ...

2018-04-12

Microbial community assembly is affected by a combination of forces that act simultaneously, but the mechanisms underpinning their relative influences remain elusive. This gap strongly limits our ability to predict human impacts on microbial communities and the processes they regulate. Here, we experimentally demonstrate that increased salinity stress, food web alteration and nutrient loading interact to drive outcomes in salt marsh fungal leaf communities. Both salinity stress and food web alterations drove communities to deterministically diverge, resulting in distinct fungal communities. Increased nutrient loads, nevertheless, partially suppressed the influence of other factors as determinants of fungal assembly. Using a nullmore » model approach, we found that increased nutrient loads enhanced the relative importance of stochastic over deterministic divergent processes; without increased nutrient loads, samples from different treatments showed a relatively (deterministic) divergent community assembly whereas increased nutrient loads drove the system to more stochastic assemblies, suppressing the effect of other treatments. These results demonstrate that common anthropogenic modifications can interact to control fungal community assembly. As a result, our results suggest that when the environmental conditions are spatially heterogeneous (as in our case, caused by specific combinations of experimental treatments), increased stochasticity caused by greater nutrient inputs can reduce the importance of deterministic filters that otherwise caused divergence, thus driving to microbial community homogenization.« less

Nitrogen enrichment suppresses other environmental drivers and homogenizes salt marsh leaf microbiome.

PubMed

Daleo, Pedro; Alberti, Juan; Jumpponen, Ari; Veach, Allison; Ialonardi, Florencia; Iribarne, Oscar; Silliman, Brian

2018-06-01

Microbial community assembly is affected by a combination of forces that act simultaneously, but the mechanisms underpinning their relative influences remain elusive. This gap strongly limits our ability to predict human impacts on microbial communities and the processes they regulate. Here, we experimentally demonstrate that increased salinity stress, food web alteration and nutrient loading interact to drive outcomes in salt marsh fungal leaf communities. Both salinity stress and food web alterations drove communities to deterministically diverge, resulting in distinct fungal communities. Increased nutrient loads, nevertheless, partially suppressed the influence of other factors as determinants of fungal assembly. Using a null model approach, we found that increased nutrient loads enhanced the relative importance of stochastic over deterministic divergent processes; without increased nutrient loads, samples from different treatments showed a relatively (deterministic) divergent community assembly whereas increased nutrient loads drove the system to more stochastic assemblies, suppressing the effect of other treatments. These results demonstrate that common anthropogenic modifications can interact to control fungal community assembly. Furthermore, our results suggest that when the environmental conditions are spatially heterogeneous (as in our case, caused by specific combinations of experimental treatments), increased stochasticity caused by greater nutrient inputs can reduce the importance of deterministic filters that otherwise caused divergence, thus driving to microbial community homogenization. © 2018 by the Ecological Society of America.

Nitrogen enrichment suppresses other environmental drivers and homogenizes salt marsh leaf microbiome

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daleo, Pedro; Alberti, Juan; Jumpponen, Ari

Microbial community assembly is affected by a combination of forces that act simultaneously, but the mechanisms underpinning their relative influences remain elusive. This gap strongly limits our ability to predict human impacts on microbial communities and the processes they regulate. Here, we experimentally demonstrate that increased salinity stress, food web alteration and nutrient loading interact to drive outcomes in salt marsh fungal leaf communities. Both salinity stress and food web alterations drove communities to deterministically diverge, resulting in distinct fungal communities. Increased nutrient loads, nevertheless, partially suppressed the influence of other factors as determinants of fungal assembly. Using a nullmore » model approach, we found that increased nutrient loads enhanced the relative importance of stochastic over deterministic divergent processes; without increased nutrient loads, samples from different treatments showed a relatively (deterministic) divergent community assembly whereas increased nutrient loads drove the system to more stochastic assemblies, suppressing the effect of other treatments. These results demonstrate that common anthropogenic modifications can interact to control fungal community assembly. As a result, our results suggest that when the environmental conditions are spatially heterogeneous (as in our case, caused by specific combinations of experimental treatments), increased stochasticity caused by greater nutrient inputs can reduce the importance of deterministic filters that otherwise caused divergence, thus driving to microbial community homogenization.« less

Evaluation of a Direct-Fed Microbial Product Effect on the Prevalence and Load of Escherichia coli O157:H7 in Feedlot Cattle

USDA-ARS?s Scientific Manuscript database

Direct fed microbials (DFM) have been identified as potential pre-harvest interventions for the reduction of foodborne bacterial pathogens such as E. coli O157:H7. This study evaluated the efficacy of a direct fed microbial (DFM) consisting of Bacillus subtilis strain 166 as an antimicrobial interve...

Coastal ocean acidification: The other eutrophication problem

EPA Science Inventory

Increased nutrient loading into estuaries causes the accumulation of algal biomass, and microbial degradation of this organic matter decreases oxygen levels and contributes towards hypoxia. A second, often overlooked consequence of microbial degradation of organic matter is the p...

The impact of loading approach and biological activity on NOM removal by ion exchange resins.

PubMed

Winter, Joerg; Wray, Heather E; Schulz, Martin; Vortisch, Roman; Barbeau, Benoit; Bérubé, Pierre R

2018-05-01

The present study investigated the impact of different loading approaches and microbial activity on the Natural Organic Matter (NOM) removal efficiency and capacity of ion exchange resins. Gaining further knowledge on the impact of loading approaches is of relevance because laboratory-scale multiple loading tests (MLTs) have been introduced as a simpler and faster alternative to column tests for predicting the performance of IEX, but only anecdotal evidence exists to support their ability to forecast contaminant removal and runtime until breakthrough of IEX systems. The overall trends observed for the removal and the time to breakthrough of organic material estimated using MLTs differed from those estimated using column tests. The results nonetheless suggest that MLTs could best be used as an effective tool to screen different ion exchange resins in terms of their ability to remove various contaminants of interest from different raw waters. The microbial activity was also observed to impact the removal and time to breakthrough. In the absence of regeneration, a microbial community rapidly established itself in ion exchange columns and contributed to the removal of organic material. Biological ion exchange (BIEX) removed more organic material and enabled operation beyond the point when the resin capacity would have otherwise been exhausted using conventional (i.e. in the absence of a microbial community) ion exchange. Furthermore, significantly greater removal of organic matter could be achieved with BIEX than biological activated carbon (BAC) (i.e. 56 ± 7% vs. 15 ± 5%, respectively) when operated at similar loading rates. The results suggest that for some raw waters, BIEX could replace BAC as the technology of choice for the removal of organic material. Copyright © 2018 Elsevier Ltd. All rights reserved.

Performance assessment and microbial diversity of two pilot scale multi-stage sub-surface flow constructed wetland systems.

PubMed

Babatunde, A O; Miranda-CasoLuengo, Raul; Imtiaz, Mehreen; Zhao, Y Q; Meijer, Wim G

2016-08-01

This study assessed the performance and diversity of microbial communities in multi-stage sub-surface flow constructed wetland systems (CWs). Our aim was to assess the impact of configuration on treatment performance and microbial diversity in the systems. Results indicate that at loading rates up to 100gBOD5/(m(2)·day), similar treatment performances can be achieved using either a 3 or 4 stage configuration. In the case of phosphorus (P), the impact of configuration was less obvious and a minimum of 80% P removal can be expected for loadings up to 10gP/(m(2)·day) based on the performance results obtained within the first 16months of operation. Microbial analysis showed an increased bacterial diversity in stage four compared to the first stage. These results indicate that the design and configuration of multi-stage constructed wetland systems may have an impact on the treatment performance and the composition of the microbial community in the systems, and such knowledge can be used to improve their design and performance. Copyright © 2016. Published by Elsevier B.V.

Microbial burden of some herbal antimalarials marketed at Elele, Rivers State.

PubMed

Tatfeng, Y M; Olama, E H; Ojo, T O

2009-12-30

Herbal antimalarials still remain an alternative to our traditional communities who can not afford orthodox antimalarials. This study was aimed at investigating the microbial quality of six herbal antimalarials using standard microbiological methods. Of the six preparations analyzed, "schnapps", palm wine and water were the media of preparation; the water base preparations recorded higher microbial load. The mean microbial load was 159.5 × 10(5) cfu/ml and 217.4 × 10(2)cfu/ml in water and alcohol base preparations respectively. The microbial profile of the preparations showed that the schnapps base preparations were predominantly contaminated with Bacillus sp (Aerobic spore bearers) and Mucor spp. The palm wine preparation harboured Bacillus sp, yeasts and Mucor spp while the water base preparations had several isolates such as Staphylococcus epidermidis, Pseudomonas aeruginosa, Escherichia coli 0157H7, Proteus mirabilis, Enterococcus feacalis, Serratia marcensces, Staph. aureus, Bacillus spp and Mucor spp. Conclusively, this study underlines the public health importance of these preparations given the high burden of such human pathogen as Ecoli O157H7, Ps aeruginosa, Stahp aureus, etc. in the preparations.

Inflight Microbial Monitoring - An Alternative Method to Culture Based Detection Currently Used on the International Space Station

NASA Technical Reports Server (NTRS)

Khodadad, Christina L.; Birmele, Michele N.; Hummerick, Mary E.; Roman, Monsi; Smith, David J.

2015-01-01

Microorganisms including potential human pathogens have been detected on the International Space Station (ISS). The potential to introduce new microorganisms occurs with every exchange of crew or addition of equipment or supplies. Current microbial monitoring methods require enrichment of microorganisms and a 48-hour incubation time resulting in an increase in microbial load, detecting a limited number of unidentified microorganisms. An expedient, low-cost, in-flight method of microbial detection, identification, and enumeration is warranted.

Wetlands for Wastewater: a Visual Approach to Microbial Dynamics

NASA Astrophysics Data System (ADS)

Joubert, L.; Wolfaardt, G.; Du Plessis, K.

2007-12-01

The complex character of distillery wastewater comprises high concentrations of sugars, lignins, hemicelluloses, dextrans, resins, polyphenols and organic acids which are recalcitrant to biodegradation. Microorganisms play a key role in the production and degradation of organic matter, environmental pollutants, and cycling of nutrients and metals. Due to their short life cycles microbes respond rapidly to external nutrient loading, with major consequences for the stability of biological systems. We evaluated the feasibility of wetlands to treat winery and distillery effluents in experimental systems based on constructed wetlands, including down-scaled on-site distillery wetlands, small-scale controlled greenhouse systems, and bench-scale mesocosms. Chemical, visual and molecular fingerprinting (t-RFLP) techniques were applied to study the dynamics of planktonic and attached (biofilm) communities at various points in wetlands of different size, retention time and geological substrate, and under influence of shock nutrient loadings. Variable- Pressure Scanning Electron Microscopy (VP-SEM) was applied to visualize microbial colonization, morphotype diversity and distribution, and 3D biofilm architecture. Cross-taxon and predator-prey interactions were markedly influenced by organic loading, while the presence of algae affected microbial community composition and biofilm structure. COD removal varied with geological substrate, and was positively correlated with retention time in gravel wetlands. Planktonic and biofilm communities varied markedly in different regions of the wetland and over time, as indicated by whole-community t-RFLP and VP-SEM. An integrative visual approach to community dynamics enhanced data retrieval not afforded by molecular techniques alone. The high microbial diversity along spatial and temporal gradients, and responsiveness to the physico-chemical environment, suggest that microbial communities maintain metabolic function by modifying species composition in response to fluctuations in their environment. It seems apparent that microbial community plasticity may indeed be the distinguishing characteristic of a successful wetland system.

Modeling the impact of the indigenous microbial population on the maximum population density of Salmonella on alfalfa.

PubMed

Rijgersberg, Hajo; Franz, Eelco; Nierop Groot, Masja; Tromp, Seth-Oscar

2013-07-01

Within a microbial risk assessment framework, modeling the maximum population density (MPD) of a pathogenic microorganism is important but often not considered. This paper describes a model predicting the MPD of Salmonella on alfalfa as a function of the initial contamination level, the total count of the indigenous microbial population, the maximum pathogen growth rate and the maximum population density of the indigenous microbial population. The model is parameterized by experimental data describing growth of Salmonella on sprouting alfalfa seeds at inoculum size, native microbial load and Pseudomonas fluorescens 2-79. The obtained model fits well to the experimental data, with standard errors less than ten percent of the fitted average values. The results show that the MPD of Salmonella is not only dictated by performance characteristics of Salmonella but depends on the characteristics of the indigenous microbial population like total number of cells and its growth rate. The model can improve the predictions of microbiological growth in quantitative microbial risk assessments. Using this model, the effects of preventive measures to reduce pathogenic load and a concurrent effect on the background population can be better evaluated. If competing microorganisms are more sensitive to a particular decontamination method, a pathogenic microorganism may grow faster and reach a higher level. More knowledge regarding the effect of the indigenous microbial population (size, diversity, composition) of food products on pathogen dynamics is needed in order to make adequate predictions of pathogen dynamics on various food products.

A comparison of microbial characteristics between the thermophilic and mesophilic anaerobic digesters exposed to elevated food waste loadings.

PubMed

Guo, Xiaohui; Wang, Cheng; Sun, Faqian; Zhu, Weijing; Wu, Weixiang

2014-01-01

Thermophilic and mesophilic anaerobic digestion reactors (TR and MR) using food waste as substrate were compared with emphasis on microbial responses to increasing organic loading rate (OLR). At OLR ranging from 1.0 to 2.5 g VS L(-1) d(-1), MR exhibited more stable performance compared to TR in terms of methane yield. Amplicons pyrosequencing results revealed the distinct microbial dynamics in the two reactors. Primarily, MR had greater richness and evenness of bacteria species. With OLR elevated, larger shifts of bacterial phylogeny were observed in MR; Methanosaeta dominated in archaeal community in MR while Methanothermobacter and Methanoculleus were favored in TR. The high functional redundancy in bacterial community integrated with acetoclastic methanogenesis in MR resulted in its better performance; whereas delicate interactions between hydrogen-producer and hydrogenotrophic methanogens in TR were much more prone to disruption. These results are conductive to understanding the microbial mechanisms of low methane yield during food waste anaerobic digestion. Copyright © 2013 Elsevier Ltd. All rights reserved.

Imipenem/cilastatin encapsulated polymeric nanoparticles for destroying carbapenem-resistant bacterial isolates.

PubMed

Shaaban, Mona I; Shaker, Mohamed A; Mady, Fatma M

2017-04-11

Carbapenem-resistance is an extremely growing medical threat in antibacterial therapy as the incurable resistant strains easily develop a multi-resistance action to other potent antimicrobial agents. Nonetheless, the protective delivery of current antibiotics using nano-carriers opens a tremendous approach in the antimicrobial therapy, allowing the nano-formulated antibiotics to beat these health threat pathogens. Herein, we encapsulated imipenem into biodegradable polymeric nanoparticles to destroy the imipenem-resistant bacteria and overcome the microbial adhesion and dissemination. Imipenem loaded poly Ɛ-caprolactone (PCL) and polylactide-co-glycolide (PLGA) nanocapsules were formulated using double emulsion evaporation method. The obtained nanocapsules were characterized for mean particle diameter, morphology, loading efficiency, and in vitro release. The in vitro antimicrobial and anti adhesion activities were evaluated against selected imipenem-resistant Klebsiella pneumoniae and Pseudomonas aeruginosa clinical isolates. The obtained results reveal that imipenem loaded PCL nano-formulation enhances the microbial susceptibility and antimicrobial activity of imipenem. The imipenem loaded PCL nanoparticles caused faster microbial killing within 2-3 h compared to the imipenem loaded PLGA and free drug. Successfully, PCL nanocapsules were able to protect imipenem from enzymatic degradation by resistant isolates and prevent the emergence of the resistant colonies, as it lowered the mutation prevention concentration of free imipenem by twofolds. Moreover, the imipenem loaded PCL eliminated bacterial attachment and the biofilm assembly of P. aeruginosa and K. pneumoniae planktonic bacteria by 74 and 78.4%, respectively. These promising results indicate that polymeric nanoparticles recover the efficacy of imipenem and can be considered as a new paradigm shift against multidrug-resistant isolates in treating severe bacterial infections.

The Detoxification and Degradation of Benzothiazole from the Wastewater in Microbial Electrolysis Cells

PubMed Central

Liu, Xianshu; Ding, Jie; Ren, Nanqi; Tong, Qingyue; Zhang, Luyan

2016-01-01

In this study, the high-production-volume chemical benzothiazole (BTH) from synthetic water was fully degraded into less toxic intermediates of simple organic acids using an up-flow internal circulation microbial electrolysis reactor (UICMER) under the hydraulic retention time (HRT) of 24 h. The bioelectrochemical system was operated at 25 ± 2 °C and continuous-flow mode. The BTH loading rate varied during experiments from 20 g·m−3·day−1 to 110 g·m−3·day−1. BTH and soluble COD (Chemical Oxygen Demand) removal efficiency reached 80% to 90% under all BTH loading rates. Bioluminescence based Shewanella oneidensis strain MR-1 ecotoxicity testing demonstrated that toxicity was largely decreased compared to the BTH wastewater influent and effluent of two control experiments. The results indicated that MEC (Microbial Electrolysis Cell) was useful and reliable for improving BTH wastewater treatment efficiency, enabling the microbiological reactor to more easily respond to the requirements of higher loading rate, which is meaningful for economic and efficient operation in future scale-up. PMID:27999421

The Detoxification and Degradation of Benzothiazole from the Wastewater in Microbial Electrolysis Cells.

PubMed

Liu, Xianshu; Ding, Jie; Ren, Nanqi; Tong, Qingyue; Zhang, Luyan

2016-12-20

In this study, the high-production-volume chemical benzothiazole (BTH) from synthetic water was fully degraded into less toxic intermediates of simple organic acids using an up-flow internal circulation microbial electrolysis reactor (UICMER) under the hydraulic retention time (HRT) of 24 h. The bioelectrochemical system was operated at 25 ± 2 °C and continuous-flow mode. The BTH loading rate varied during experiments from 20 g·m -3 ·day -1 to 110 g·m -3 ·day -1 . BTH and soluble COD (Chemical Oxygen Demand) removal efficiency reached 80% to 90% under all BTH loading rates. Bioluminescence based Shewanella oneidensis strain MR-1 ecotoxicity testing demonstrated that toxicity was largely decreased compared to the BTH wastewater influent and effluent of two control experiments. The results indicated that MEC (Microbial Electrolysis Cell) was useful and reliable for improving BTH wastewater treatment efficiency, enabling the microbiological reactor to more easily respond to the requirements of higher loading rate, which is meaningful for economic and efficient operation in future scale-up.

Lactic acid concentrations that reduce microbial load yet minimally impact colour and sensory characteristics of beef.

PubMed

Rodríguez-Melcón, Cristina; Alonso-Calleja, Carlos; Capita, Rosa

2017-07-01

Lactic acid (LA) has recently been approved in the EU as beef decontaminant. In order to identify the most appropriate concentration, beef samples were spray-treated with LA (2%, 3%, 4% or 5%) or left untreated (control). Microbial load (aerobic plate counts, psychrotrophs and Enterobacteriaceae), pH, instrumental colour and sensory properties were investigated at 0, 24, 72 and 120h of refrigerated storage. The reductions in bacteria after spraying ranged from 0.57 to 0.95 log units. A residual antimicrobial effect was observed so that at 120h LA reduced microbial load by up to 2 log units compared with the control samples. Samples treated with 5% LA showed the lowest redness value (a*) and hedonic scores at all sampling times. Only for samples treated with 4% LA did the sensorial shelf-life limit extend beyond 120h. It is suggested that treatment of beef with 4% LA not only may improve microbiological quality, but also may enhance sensory properties and shelf-life. Copyright © 2017. Published by Elsevier Ltd.

Effect of high loading on substrate utilization kinetics and microbial community structure in super fast submerged membrane bioreactor.

PubMed

Sözen, S; Çokgör, E U; Başaran, S Teksoy; Aysel, M; Akarsubaşı, A; Ergal, I; Kurt, H; Pala-Ozkok, I; Orhon, D

2014-05-01

The study investigated the effect of high substrate loading on substrate utilization kinetics, and changes inflicted on the composition of the microbial community in a superfast submerged membrane bioreactor. Submerged MBR was sequentially fed with a substrate mixture and acetate; its performance was monitored at steady-state, at extremely low sludge age values of 2.0, 1.0 and 0.5d, all adjusted to a single hydraulic retention time of 8.0 h. Each MBR run was repeated when substrate feeding was increased from 200 mg COD/L to 1000 mg COD/L. Substrate utilization kinetics was altered to significantly lower levels when the MBR was adjusted to higher substrate loadings. Molecular analysis of the biomass revealed that variable process kinetics could be correlated with parallel changes in the composition of the microbial community, mainly by a replacement mechanism, where newer species, better adapted to the new growth conditions, substituted others that are washed out from the system. Copyright © 2014 Elsevier Ltd. All rights reserved.

Comparative anti-microbial efficacy of Azadirachta indica irrigant with standard endodontic irrigants: A preliminary study

PubMed Central

Dutta, Arindam; Kundabala, Mala

2014-01-01

Objective: The anti-microbial efficacy of 2.5% sodium hypochlorite (SHC) and 0.2% chlorhexidine gluconate were compared with an experimental irrigant formulated from the Neem tree, Azadirachta indica A. Juss. Materials and Methods: A sample of 36 single rooted anterior teeth with periapical radiolucency and absence of response to vitality tests that required root canal treatment were selected for this study. The test irrigants and their combinations were assigned to five different groups and saline served as the control. Access cavities were prepared using an aseptic technique and samples collected for both anaerobic culture and Gram stained smears, followed by irrigation and sample collection again. The number of organisms were expressed in colony forming units/ml after 72 h of incubation; the smears were analyzed for their microbial loads and tissue clearance and assessed as per defined criteria. Results: Our results found the maximum reduction in microbial loads, when analyzed by culture method, with a combination of SHC and the experimental neem irrigant. Maximum tissue clearance on the Gram Stained smears was also found with the same combination. Conclusion: Neem irrigant has anti-microbial efficacy and can be considered for endodontic use. PMID:24778508

Evaluation of instant cup noodle, irradiated for immuno-compromised patients

NASA Astrophysics Data System (ADS)

Lee, Ji-Hye; Kim, Jae-Kyung; Park, Jae-Nam; Yoon, Young-Min; Sung, Nak-Yun; Kim, Jae-Hun; Song, Beom-Seok; Yook, Hong-Sun; Kim, Byeong-Keun; Lee, Ju-Woon

2012-08-01

In the present study, initial microbial load of instant cup noodle (ICN) was investigated and gamma irradiation applied to develop immuno-compromised patients food for their safe consumption. The initial microbial population of dried vegetable and meat, and noodle was below the detection limit (1 log CFU/g); however, that of seasoning powder was just above 4 log CFU/g. Moreover, rehydrated-ICN with water at 100 °C still show above 3 log CFU/g of microbial load, which indicates the need for an additional process to control microbial safety of the seasoning powder. The total aerobic bacteria in seasoning powder and rehydrated-ICN could be controlled with 17 kGy gamma irradiation. This result referred 17 kGy gamma irradiation could reach 'practical sterility' of ICN. The overall difference in sensory properties between the non-irradiated and irradiated ICN was insignificant. Thus, gamma irradiation could improve the microbial quality of ICN, and reduce the risk of infection posed by the seasoning powder, without any adverse effects on their sensory quality. These results suggest that gamma-irradiated ICN can be used as a snack food for immuno-compromised patients.

LIBRARY-DEPENDENT MICROBIAL SOURCE TRACKING OF ENTEROCOCCUS SP. USING AFLP AND BOX-PCR

EPA Science Inventory

Library-dependent microbial source tracking (LD MST) methods are one of the approaches used to identify nonpoint sources of fecal contamination in support of total maximum daily load implementation. However, LD MST methods have been questioned due to the high temporal and spatial...

EFFECT OF NUTRIENT LOADING ON BIOGEOCHEMICAL AND MICROBIAL PROCESSES IN A NEW ENGLAND HIGH SALT MARSH, SPARTINA PATNES, (AITON MUHL)

EPA Science Inventory

Coastal marshes represent an important transitional zone between uplands and estuaries and can assimilate nutrient inputs from uplands. We examined the effects of nitrogen (N) and phosphorus (P) fertilization on biogeochemical and microbial processes during the summer growing sea...

[Study on the stability of tetrandrine microsphere].

PubMed

Cheng, Guohu; Luo, Jiabo

2005-05-01

To study the stability of Tetrandrine Microsphere. Higher speed test and room temperature test were adopted to investigate the indexes, such as properties of appearance, amount of medicine loaded, seal rate, seepage rate, microbial stability, etc. Through the test of six months, properties of appearance, amount of medicine loaded, seal rate, seepage rate, microbial stability have not obviously change. But after testing for 6 months with higher temperature, the seal rate was reduced, and the seepage rate was increased. Tetrandrine microsphere is steady under the room temperature condition, but is unstable to hot, and ought to keep in conformity with low-temperature.

Vertical and horizontal distributions of microbial abundances and enzymatic activities in propylene-glycol-affected soils.

PubMed

Biró, Borbála; Toscano, Giuseppe; Horváth, Nikoletta; Matics, Heléna; Domonkos, Mónika; Scotti, Riccardo; Rao, Maria A; Wejden, Bente; French, Helen K

2014-01-01

The natural microbial activity in the unsaturated soil is vital for protecting groundwater in areas where high loads of biodegradable contaminants are supplied to the surface, which usually is the case for airports using aircraft de-icing fluids (ADF) in the cold season. Horizontal and vertical distributions of microbial abundance were assessed along the western runway of Oslo Airport (Gardermoen, Norway) to monitor the effect of ADF dispersion with special reference to the component with the highest chemical oxygen demand (COD), propylene glycol (PG). Microbial abundance was evaluated by several biondicators: colony-forming units (CFU) of some physiological groups (aerobic and anaerobic heterotrophs and microscopic fungi), most probable numbers (MPN) of PG degraders, selected catabolic enzymatic activities (fluorescein diacetate (FDA) hydrolase, dehydrogenase, and β-glucosidase). High correlations were found between the enzymatic activities and microbial counts in vertical soil profiles. All microbial abundance indicators showed a steep drop in the first meter of soil depth. The vertical distribution of microbial abundance can be correlated by a decreasing exponential function of depth. The horizontal trend of microbial abundance (evaluated as total aerobic CFU, MPN of PG-degraders, and FDA hydrolase activity) assessed in the surface soil at an increasing distance from the runway is correlated negatively with the PG and COD loads, suggesting the relevance of other chemicals in the modulation of microbial growth. The possible role of potassium formate, component of runway de-icers, has been tested in the laboratory by using mixed cultures of Pseudomonas spp., obtained by enrichment with a selective PG medium from soil samples taken at the most contaminated area near the runway. The inhibitory effect of formate on the growth of PG degraders is proven by the reduction of biomass yield on PG in the presence of formate.

Assessment of the impact of textile effluents on microbial diversity in Tirupur district, Tamil Nadu

NASA Astrophysics Data System (ADS)

Prabha, Shashi; Gogoi, Anindita; Mazumder, Payal; Ramanathan, AL.; Kumar, Manish

2017-09-01

The expedited advent of urbanization and industrialization for economic growth has adversely affected the biological diversity, which is one of the major concerns of the developing countries. Microbes play a crucial role in decontaminating polluted sites and degrades pollution load of textile effluent. The present study was based on identification of microbial diversity along the Noyaal river of Tirupur area. River water samples from industrial and non-industrial sites and effluent samples of before and after treatment were tested and it was found that microbial diversity was higher in the river water at the industrial site (Kasipalayam) as compared to the non-industrial site (Perur). Similarly, the microbial populations were found to be high in the untreated effluent as compared to the treated one by conventional treatment systems. Similar trends were observed for MBR treatment systems as well. Pseudomonas sp ., Achromobacter sp. (bacterial species) and Aspergillus fumigates (fungal species), found exclusively at the industrial site have been reported to possess decolorization potential of dye effluent, thus can be used for treatment of dye effluent. The comparison of different microbial communities from different dye wastewater sources and textile effluents was done, which showed that the microbes degrade dyestuffs, reduce toxicity of wastewaters, etc. From the study, it can be concluded that the microbial community helps to check on the pollutants and minimize their affect. Therefore, there is a need to understand the systematic variation in microbial diversity with the accumulation of pollution load through monitoring.

Using blue mussels (Mytilus spp.) as biosentinels of Cryptosporidium spp. and Toxoplasma gondii contamination in marine aquatic environments

USDA-ARS?s Scientific Manuscript database

Methods to monitor microbial contamination typically involve collecting discrete samples at specific time-points and analyzing for a single contaminant. While informative, many of these methods suffer from poor recovery rates and only provide a snapshot of the microbial load at the time of collectio...

21 CFR 172.133 - Dimethyl dicarbonate.

Code of Federal Regulations, 2011 CFR

2011-04-01

... additive is used or intended for use as a microbial control agent in the following beverages under normal circumstances of bottling, canning, or other forms of final packaging, where the viable microbial load has been... juice, fruit flavor, or both, with juice content not to exceed 50 percent, in an amount not to exceed...

Treatment of phenolic wastewater in an anaerobic fixed bed reactor (AFBR) - recovery after shock loading.

PubMed

Bajaj, Mini; Gallert, Claudia; Winter, Josef

2009-03-15

An anaerobic fixed bed reactor (AFBR) was run for 550 days with a mixed microbial flora to stabilize synthetic wastewater that contained glucose and phenol as main carbon sources. The influent phenol concentration was gradually increased from 2 to 40 mmol/l within 221 days. The microbial flora was able to adapt to this high phenol concentration with an average of 94% phenol removal. Microbial adaptation at such a high phenol concentration is not reported elsewhere. The maximum phenol removal observed before the phenol shock load was 39.47 mmol/l or 3.7 g phenol/l at a hydraulic retention time (HRT) of 2.5 days and an organic loading rate (OLR) of 5.3 g/l.d which amounts to a phenol removal rate of ca. 15.8 mmol phenol/l.d. The chemical oxygen demand (COD) removal before exposing the reactor to a shock load corresponded with phenol removal. A shock load was induced in the reactor by increasing the phenol concentration from 40 to 50 mmol/l in the influent. The maximum phenol removal rate observed after shock load was 18 mmol/l.d at 5.7 g COD/l.d. But this was not a stable rate and a consistent drop in COD and phenol removal was observed for 1 week, followed by a sharp decline and production of fatty acids. Recovery of the reactor was possible only when no feed was provided to the reactor for 1 month and the phenol concentration was increased gradually. When glucose was omitted from the influent, unknown intermediates of anaerobic phenol metabolism were observed for some time.

Effects of microbial DNA on human DNA profiles generated using the PowerPlex® 16 HS system.

PubMed

Dembinski, Gina M; Picard, Christine J

2017-11-01

Most crime scenes are not sterile and therefore may be contaminated with environmental DNA, especially if a decomposing body is found. Collecting biological evidence from this individual will yield DNA samples mixed with microbial DNA. This also becomes important if postmortem swabs are collected from sexually assaulted victims. Although genotyping kits undergo validation tests, including bacterial screens, they do not account for the diverse microbial load during decomposition. We investigated the effect of spiking human DNA samples with known concentrations of DNA from 17 microbe species associated with decomposition on DNA profiles produced using the Promega PowerPlex ® HS system. Two species, Bacillus subtilis and Mycobacterium smegmatis, produced an extraneous allele at the TPOX locus. When repeated with the PowerPlex ® Fusion kit, the extra allele no longer amplified with these two species. This experiment demonstrates that caution should be exhibited if microbial load is high and the PowerPlex ® 16HS system is used. Copyright © 2017 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

Total electron acceptor loading and composition affect hexavalent uranium reduction and microbial community structure in a membrane biofilm reactor.

PubMed

Ontiveros-Valencia, Aura; Zhou, Chen; Ilhan, Zehra Esra; de Saint Cyr, Louis Cornette; Krajmalnik-Brown, Rosa; Rittmann, Bruce E

2017-11-15

Molecular microbiology tools (i.e., 16S rDNA gene sequencing) were employed to elucidate changes in the microbial community structure according to the total electron acceptor loading (controlled by influent flow rate and/or medium composition) in a H 2 -based membrane biofilm reactor evaluated for removal of hexavalent uranium. Once nitrate, sulfate, and dissolved oxygen were replaced by U(VI) and bicarbonate and the total acceptor loading was lowered, slow-growing bacteria capable of reducing U(VI) to U(IV) dominated in the biofilm community: Replacing denitrifying bacteria Rhodocyclales and Burkholderiales were spore-producing Clostridiales and Natranaerobiales. Though potentially competing for electrons with U(VI) reducers, homo-acetogens helped attain steady U(VI) reduction, while methanogenesis inhibited U(VI) reduction. U(VI) reduction was reinstated through suppression of methanogenesis by addition of bromoethanesulfonate or by competition from SRB when sulfate was re-introduced. Predictive metagenome analysis further points out community changes in response to alterations in the electron-acceptor loading: Sporulation and homo-acetogenesis were critical factors for strengthening stable microbial U(VI) reduction. This study documents that sporulation was important to long-term U(VI) reduction, whether or not microorganisms that carry out U(VI) reduction mediated by cytochrome c 3 , such as SRB and ferric-iron-reducers, were inhibited. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fabrication and anti-microbial evaluation of drug loaded polylactide space filler intended for ridge preservation following tooth extraction

PubMed Central

Thomas, Nebu George; Sanil, George P.; Rajmohan, Gopimohan; Prabhakaran, Jayachandran V.; Panda, Amulya K.

2011-01-01

Background: The preservation or reduction of alveolar ridge resorption following tooth extraction is important in patients especially for those intended for implants at a later stage. One way to achieve this is by using membranes, graft materials, and biodegradable space fillers to prevent alveolar bone resorption and promote regeneration. A major attraction for using biodegradable and biocompatible polymers as space fillers for ridge preservation is their safety profile in comparison to xenograft materials like lyophilized bone and collagen. Materials and Methods: Biocompatible polylactide space fillers were fabricated by fusing porous polylactide particles. The sponges were loaded with drugs by placing them in the respective solutions. Pseudomonas aeruginosa was isolated from a chronic periodontitis patient and in vitro anti-microbial evaluation was done with the drug loaded sponges. Results: Chlorhexidine loaded space filler showed significant anti microbial effect against multiple drug resistant Pseudomonas aeruginosa isolated from a patient with chronic periodontitis. Conclusion: The results of this study indicate that biodegradable drug releasing polylactide space fillers has the potential to be used for ridge preservation following tooth extraction. Release of drugs in the socket may prove useful in preventing development of alveolar osteitis post extraction which can interfere with normal healing of the socket. Synthetic biodegradable polymers also exhibit a controlled degradation rate to achieve complete resorption within the intended time. PMID:22028514

Characterization of bacterial structures in two-stage moving-bed biofilm reactor (MBBR) during nitrification of the landfill leachate.

PubMed

Ciesielski, Slawomir; Kulikowska, Dorota; Kaczowka, Ewelina; Kowal, Przemysław

2010-07-01

Differences in DNA banding patterns, obtained by ribosomal intergenic spacer analysis (RISA), and nitrification were followed in a moving-bed biofilm reactor (MBBR) receiving municipal landfill leachate. Complete nitrification (> 99%) to nitrate was obtained in the two-stage MBBR system with an ammonium load of 1.09 g N-NH(4)/m(2).d. Increasing the ammonium load to 2.03 g N-NH(4)/m(2).d or more caused a decline in process efficiency to 70-86%. Moreover, at the highest ammonium load (3.76 g N-NH(4)/m(2).d), nitrite was the predominant product of nitrification. Community succession was evident in both compartments in response to changes in ammonium load. Non-metric multidimensional scaling (NMDS) supported by similarity analysis (ANOSIM) showed that microbial biofilm communities differed between compartments. The microbial biofilm was composed mainly of ammonia-oxidizing bacteria (AOB), with Nitrosomonas europeae and N. eutropha being most abundant. These results suggest that high ammonium concentrations select for particular AOB strains.

A biofilter integrated with gas membrane separation unit for the treatment of fluctuating styrene loads.

PubMed

Li, Lin; Lian, Jing; Han, Yunping; Liu, Junxin

2012-05-01

Biofiltration for volatile organic compound control in waste gas streams is best operated at steady contaminant loadings. To provide long-term stable operation of a biofilter under adverse contaminant feeding conditions, an integrated bioreactor system with a gas separation membrane module installed after a biofilter was proposed for styrene treatment. Styrene was treated effectively, with average styrene effluent concentrations maintained at less than 50 mg m(-3) and a total removal efficiency of over 96% achieved when the biofiltration column faced fluctuating loads. The maximum elimination capacity of the integrated bioreactor system was 93.8 g m(-3)h(-1), which was higher than that obtained with the biofiltration column alone. The combination of these two processes (microbial and chemical) led to more efficient elimination of styrene and buffering of the fluctuating loads. The factors on gas membrane separation, microbial characteristics in the integrated bioreactor and membrane fouling were also investigated in this study. Copyright © 2012 Elsevier Ltd. All rights reserved.

DART Employees at Work

NASA Image and Video Library

2014-10-31

The Dust Atmospheric Recovery Technology, or DART, spacecraft is being assembled in a laboratory inside the Space Life Sciences Lab at NASA’s Kennedy Space Center in Florida. DART will characterize the dust loading and microbial diversity in the atmosphere over Florida during summer months with a special emphasis on their interactions during an African dust storm. DART will be used to collect atmospheric aerosols and suspended microbial cells over Florida and Kennedy. Results will help predict the risks of excessive microbial contamination adhering to spacecraft surfaces.

DART Employees at Work

NASA Image and Video Library

2014-10-31

A researcher at NASA’s Kennedy Space Center in Florida checks a reading on the Dust Atmospheric Recovery Technology, or DART, spacecraft inside a laboratory at the Space Life Sciences Lab. DART will characterize the dust loading and microbial diversity in the atmosphere over Florida during summer months with a special emphasis on their interactions during an African dust storm. DART will be used to collect atmospheric aerosols and suspended microbial cells over Florida and Kennedy. Results will help predict the risks of excessive microbial contamination adhering to spacecraft surfaces.

DART Employees at Work

NASA Image and Video Library

2014-10-31

Researchers at NASA’s Kennedy Space Center in Florida check readings on the Dust Atmospheric Recovery Technology, or DART, spacecraft inside a laboratory at the Space Life Sciences Lab. DART will characterize the dust loading and microbial diversity in the atmosphere over Florida during summer months with a special emphasis on their interactions during an African dust storm. DART will be used to collect atmospheric aerosols and suspended microbial cells over Florida and Kennedy. Results will help predict the risks of excessive microbial contamination adhering to spacecraft surfaces.

Microbial community dynamics and biogas production from manure fractions in sludge bed anaerobic digestion.

PubMed

Nordgård, A S R; Bergland, W H; Bakke, R; Vadstein, O; Østgaard, K; Bakke, I

2015-12-01

To elucidate how granular sludge inoculum and particle-rich organic loading affect the structure of the microbial communities and process performance in upflow anaerobic sludge bed (UASB) reactors. We investigated four reactors run on dairy manure filtrate and four on pig manure supernatant for three months achieving similar methane yields. The reactors fed with less particle rich pig manure stabilized faster and had highest capacity. Microbial community dynamics analysed by a PCR/denaturing gradient gel electrophoresis approach showed that influent was a major determinant for the composition of the reactor communities. Comparisons of pre- and non-adapted inoculum in the reactors run on pig manure supernatant showed that the community structure of the nonadapted inoculum adapted in approximately two months. Microbiota variance partitioning analysis revealed that running time, organic loading rate and inoculum together explained 26 and 31% of the variance in bacterial and archaeal communities respectively. The microbial communities of UASBs adapted to the reactor conditions in treatment of particle rich manure fractions, obtaining high capacity, especially on pig manure supernatant. These findings provide relevant insight into the microbial community dynamics in startup and operation of sludge bed reactors for methane production from slurry fractions, a major potential source of biogas. © 2015 The Society for Applied Microbiology.

Heterogeneity of interactions of microbial communities in regions of Taihu Lake with different nutrient loadings: A network analysis.

PubMed

Cao, Xinyi; Zhao, Dayong; Xu, Huimin; Huang, Rui; Zeng, Jin; Yu, Zhongbo

2018-06-11

To investigate the differences in the interactions of microbial communities in two regions in Taihu Lake with different nutrient loadings [Meiliang Bay (MLB) and Xukou Bay (XKB)], water samples were collected and both intra- and inter-kingdom microbial community interactions were examined with network analysis. It is demonstrated that all of the bacterioplankton, microeukaryotes and inter-kingdom communities networks in Taihu Lake were non-random. For the networks of bacterioplankton and inter-kingdom community in XKB, higher clustering coefficient and average degree but lower average path length indexes were observed, indicating the nodes in XKB were more clustered and closely connected with plenty edges than those of MLB. The bacterioplankton and inter-kingdom networks were considerably larger and more complex with more module hubs and connectors in XKB compared with those of MLB, whereas the microeukaryotes networks were comparable and had no module hubs or connectors in the two lake zones. The phyla of Acidobacteria, Cyanobacteria and Planctomycetes maintained greater cooperation with other phyla in XKB, rather than competition. The relationships between microbial communities and environmental factors in MLB were weaker. Compared with the microbial community networks of XKB, less modules in networks of MLB were significantly correlated with total phosphorous and total nitrogen.

Microbial community dynamics during assays of harbour oil spill bioremediation: a microscale simulation study.

PubMed

Cappello, S; Caruso, G; Zampino, D; Monticelli, L S; Maimone, G; Denaro, R; Tripodo, B; Troussellier, M; Yakimov, M; Giuliano, L

2007-01-01

Microcosm experiments simulating an oil spill event were performed to evaluate the response of the natural microbial community structure of Messina harbour seawater following the accidental load of petroleum. An experimental harbour seawater microcosm, supplemented with nutrients and crude oil, was monitored above 15 days in comparison with unpolluted ones (control microcosms). Bacterial cells were counted with a Live/Dead BacLight viability kit; leucine aminopeptidase, beta-glucosidase, alkaline phosphatase, lipase and esterase enzymes were measured using fluorogenic substrates. The microbial community dynamic was monitored by isolation of total RNA, RT-PCR amplification of 16S rRNA, cloning and sequencing. Oil addition stimulated an increase of the total bacterial abundance, leucine aminopeptidase and phosphatase activity rates, as well as a change in the community structure. This suggested a prompt response of micro-organisms to the load of petroleum hydrocarbons. The present study on the viability, specific composition and metabolic characteristics of the microbial community allows a more precise assessment of oil pollution. Both structural and functional parameters offer interesting perspectives as indicators to monitor changes caused by petroleum hydrocarbons. A better knowledge of microbial structural successions at oil-polluted sites is essential for environmental bioremediation. Data obtained in microcosm studies improve our understanding of natural processes occurring during oil spills.

Differences in Hyporheic-Zone Microbial Community Structure along a Heavy-Metal Contamination Gradient

PubMed Central

Feris, Kevin; Ramsey, Philip; Frazar, Chris; Moore, Johnnie N.; Gannon, James E.; Holben, William E.

2003-01-01

The hyporheic zone of a river is nonphotic, has steep chemical and redox gradients, and has a heterotrophic food web based on the consumption of organic carbon entrained from downwelling surface water or from upwelling groundwater. The microbial communities in the hyporheic zone are an important component of these heterotrophic food webs and perform essential functions in lotic ecosystems. Using a suite of methods (denaturing gradient gel electrophoresis, 16S rRNA phylogeny, phospholipid fatty acid analysis, direct microscopic enumeration, and quantitative PCR), we compared the microbial communities inhabiting the hyporheic zone of six different river sites that encompass a wide range of sediment metal loads resulting from large base-metal mining activity in the region. There was no correlation between sediment metal content and the total hyporheic microbial biomass present within each site. However, microbial community structure showed a significant linear relationship with the sediment metal loads. The abundances of four phylogenetic groups (groups I, II, III, and IV) most closely related to α-, β-, and γ-proteobacteria and the cyanobacteria, respectively, were determined. The sediment metal content gradient was positively correlated with group III abundance and negatively correlated with group II abundance. No correlation was apparent with regard to group I or IV abundance. This is the first documentation of a relationship between fluvially deposited heavy-metal contamination and hyporheic microbial community structure. The information presented here may be useful in predicting long-term effects of heavy-metal contamination in streams and provides a basis for further studies of metal effects on hyporheic microbial communities. PMID:12957946

EFFECTS OF NUTRIENT LOADING ON BIOGEOCHEMICAL AND MICROBIAL PROCESSES IN A NEW ENGLAND SALT MARSH

EPA Science Inventory

Coastal marshes represent an important transitional zone between uplands and estuaries. One important function of marshes is to assimilate nutrient inputs from uplands, thus providing a buffer for anthropogenic nutrient loads. We examined the effects of nitrogen (N) and phosphoru...

Microbial community adaptation influences long-chain fatty acid conversion during anaerobic codigestion of fats, oils, and grease with municipal sludge.

PubMed

Ziels, Ryan M; Karlsson, Anna; Beck, David A C; Ejlertsson, Jörgen; Yekta, Sepehr Shakeri; Bjorn, Annika; Stensel, H David; Svensson, Bo H

2016-10-15

Codigesting fats, oils, and greases with municipal wastewater sludge can greatly improve biomethane recovery at wastewater treatment facilities. Process loading rates of fats, oils, and greases have been previously tested with little knowledge of the digester microbial community structure, and high transient fat loadings have led to long chain fatty acid (LCFA) accumulation and digester upsets. This study utilized recently-developed quantitative PCR assays for syntrophic LCFA-degrading bacteria along with 16S amplicon sequencing to relate changes in microbial community structure to LCFA accumulation during transient loading increases to an anaerobic codigester receiving waste restaurant oil and municipal wastewater sludge. The 16S rRNA gene concentration of the syntrophic β-oxidizing genus Syntrophomonas increased to ∼15% of the Bacteria community in the codigester, but stayed below 3% in the control digester that was fed only wastewater sludge. Methanosaeta and Methanospirillum were the dominant methanogenic genera enriched in the codigester, and together comprised over 80% of the Archaea community by the end of the experimental period. Constrained ordination showed that changes in the codigester Bacteria and Archaea community structures were related to measures of digester performance. Notably, the effluent LCFA concentration in the codigester was positively correlated to the specific loading rate of waste oil normalized to the Syntrophomonas 16S rRNA concentration. Specific loading rates of 0-1.5 × 10(-12) g VS oil/16S gene copies-day resulted in LCFA concentrations below 30 mg/g TS, whereas LCFA accumulated up to 104 mg/g TS at higher transient loading rates. Based on the community-dependent loading limitations found, enhanced biomethane production from high loadings of fats, oils and greases can be achieved by promoting a higher biomass of slow-growing syntrophic consortia, such as with longer digester solids retention times. This work also demonstrates the potential for controlling the loading rate of fats, oils, and greases based on the analysis of the codigester community structure, such as with quantitative PCR measurements of syntrophic LCFA-degrading bacteria abundance. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of gamma irradiation on microbial load, physicochemical and sensory characteristics of soybeans (Glycine max L. Merrill)

USDA-ARS?s Scientific Manuscript database

Gamma irradiation is highly effective in inactivating microorganisms in various foods and offers a safe alternative method of food decontamination. In the present study, soybeans (Glycine max L. Merrill) were treated with 0, 1.0, 3.0, 5.0 and 10.0 KGy of gamma irradiation. Microbial populations on s...

Biofiltration of xylene using wood charcoal as the biofilter media under transient and high loading conditions.

PubMed

Singh, Kiran; Giri, B S; Sahi, Amrita; Geed, S R; Kureel, M K; Singh, Sanjay; Dubey, S K; Rai, B N; Kumar, Surendra; Upadhyay, S N; Singh, R S

2017-10-01

The main objective of this study was to evaluate the performance of wood charcoal as biofilter media under transient and high loading condition. Biofiltration of xylene was investigated for 150days in a laboratory scale unit packed with wood charcoal and inoculated with mixed microbial culture at the xylene loading rates ranged from 12 to 553gm -3 h -1 . The kinetic analysis of the xylene revealed absence of substrate inhibition and possibility of achieving higher elimination under optimum condition. The pH, temperature, pressure drop and CO 2 production rate were regularly monitored during the experiments. Throughout experimental period, the removal efficiency (RE) was found to be in the range of 65-98.7% and the maximum elimination capacity (EC) was 405.7gm -3 h -1 . Molecular characterization results show Bacillus sp. as dominating microbial group in the biofilm. Copyright © 2017 Elsevier Ltd. All rights reserved.

Experimental observations on the decay of environmental DNA from bighead and silver carps

USGS Publications Warehouse

Lance, Richard F.; Klymus, Katy E.; Richter, Cathy; Guan, Xin; Farrington, Heather L.; Carr, Matthew R.; Thompson, Nathan; Chapman, Duane C.; Baerwaldt, Kelly L.

2017-01-01

Interest in the field of environmental DNA (eDNA) is growing rapidly and eDNA surveys are becoming an important consideration for aquatic resource managers dealing with invasive species. However, in order for eDNA monitoring to mature as a research and management tool, there are several critical knowledge gaps that must be filled. One such gap is the fate of eDNA materials in the aquatic environment. Understanding the environmental factors that influence the decay of eDNA and how these factors impact detection probabilities over time and space could have significant implications for eDNA survey design and data interpretation. Here we experimentally explore decay of eDNA associated with bighead carp (Hypophthalmichthys nobilis) biological waste collected from an aquaculture filtration system and with sperm collected from captive silver carp (H. molitrix), and how decay may be influenced by differing levels of water turbulence, temperature, microbial load, and pH. We found that the decay patterns of eDNA associated with both H. nobilis biological waste and H. molitrix milt significantly fit monophasic exponential decay curves. Secondly, we observed that the highest temperature we tested resulted in a decay half-life as much as 5.5× more rapid than the lowest temperature we tested. When we suppressed microbial loads in eDNA samples, we observed that overall losses of eDNA were reduced by about 2.5×. When we amended eDNA samples with pond water the half-life of eDNA was reduced by about 2.25×, despite relatively little apparent increase in the overall microbial load. This pattern indicated that species constituency of the microbial community, in addition to microbial load, might play a critical role in eDNA degradation. A shift in pH from 6.5 to 8.0 in the samples resulted in a 1.6× reduction in eDNA halflife. Water turbulence in our study had no apparent effect on eDNA decay. When we combined different temperature, pH, and microbial load treatments to create a rapid decay condition and a slow decay condition, and tracked eDNA decay over 91 days, we observed a 5.0× greater loss of eDNA by Day 5 under rapid decay conditions than under slow decay conditions. At the end of the trials, the differences in eDNA loss between the rapid decay and baseline and slow decay conditions were 0.1× and 3.3×, respectively. Our results strongly demonstrate the potential for environmental factors to influence eDNA fate and, thus, the interpretation of eDNA survey results.

Power generation in microbial fuel cells using platinum group metal-free cathode catalyst: Effect of the catalyst loading on performance and costs

NASA Astrophysics Data System (ADS)

Santoro, Carlo; Kodali, Mounika; Herrera, Sergio; Serov, Alexey; Ieropoulos, Ioannis; Atanassov, Plamen

2018-02-01

Platinum group metal-free (PGM-free) catalyst with different loadings was investigated in air breathing electrodes microbial fuel cells (MFCs). Firstly, the electrocatalytic activity towards oxygen reduction reaction (ORR) of the catalyst was investigated by rotating ring disk electrode (RRDE) setup with different catalyst loadings. The results showed that higher loading led to an increased in the half wave potential and the limiting current and to a further decrease in the peroxide production. The electrons transferred also slightly increased with the catalyst loading up to the value of ≈3.75. This variation probably indicates that the catalyst investigated follow a 2x2e- transfer mechanism. The catalyst was integrated within activated carbon pellet-like air-breathing cathode in eight different loadings varying between 0.1 mgcm-2 and 10 mgcm-2. Performance were enhanced gradually with the increase in catalyst content. Power densities varied between 90 ± 9 μWcm-2 and 262 ± 4 μWcm-2 with catalyst loading of 0.1 mgcm-2 and 10 mgcm-2 respectively. Cost assessments related to the catalyst performance are presented. An increase in catalyst utilization led to an increase in power generated with a substantial increase in the whole costs. Also a decrease in performance due to cathode/catalyst deterioration over time led to a further increase in the costs.

MICROBIOLOGICAL SAFETY ASSESSMENT AND RISK MITIGATION OF INDIAN ROJAK (DEEP FRIED READYTO-EAT FOOD) IN SINGAPORE.

PubMed

Aung, Kyaw Thu; Lo, Jerilyn Ann Chen Ying; Chau, Man Ling; Kang, Joanne Su Lin; Yap, Hooi Ming; Gutiérrez, Ramona Alikiiteaga; Yuk, Hyun-Gyun; Ng, Lee Ching

2016-11-01

We conducted a microbiological assessment of Indian Rojak, a popular deep fried food in Singapore to evaluate its overall microbial quality, assess the effectiveness of reheating and identify key food items that could contribute to the microbial load of the dish. In 2009, an outbreak of foodborne illness associated with this food led to 154 reported cases of acute gastroenteritis, 48 were hospitalized and 2 died. Vibrio parahaemolyticus was isolated from the patients. We evaluated 455 Indian Rojak ingredients from 35 stalls; no Salmonella spp, Vibrio cholerae/parahaemolyticus or Escherichia coli O157:H7 were recovered from the studied samples. The reheating by the food handlers significantly reduced the overall median Standard Plate Count (SPC) of food from 4.5 to 2.7 log colony forming units (CFU)/g (p<0.05). The cooked ingredients with the highest microbial loads were tofu and fish cake, with those purchased from wet markets having significantly higher bacterial loads than those purchased from supermarkets (p<0.05). The Rojak gravy had the lowest median bacterial load (1.9 log CFU/g). Raw, ready-to-eat vegetables, namely green chillis, cucumbers and onions had higher levels ranging from 5.9 to 6.1 log CFU/g. Contamination with E. coli, Staphylococcus aureus, and Bacillus cereus was seen with some of the ready-to-eat raw vegetables. Repeated education of food handlers with emphasis on good hygiene practices should be conducted to reduce the risk of foodborne illnesses.

Development, optimization and evaluation of polymeric electrospun nanofiber: A tool for local delivery of fluconazole for management of vaginal candidiasis.

PubMed

Sharma, Rahul; Garg, Tarun; Goyal, Amit K; Rath, Goutam

2016-01-01

The present study is designed to explore the localized delivery of fluconazole using mucoadhesive polymeric nanofibers. Drug-loaded polymeric nanofibers were fabricated by the electrospinning method using polyvinyl alcohol (PVA) as the polymeric constituent. The prepared nanofibers were found to be uniform, non-beaded and non-woven, with the diameter of the fibers ranging from 150 to 180 nm. Further drug release studies indicate a sustained release of fluconazole over a period of 6 h. The results of studies on anti-microbial activity indicated that drug-loaded polymeric nanofibers exhibit superior anti-microbial activity against Candida albicans, when compared to the plain drug.

KSC-2014-4900

NASA Image and Video Library

2014-10-31

CAPE CANAVERAL, Fla. – A researcher at NASA’s Kennedy Space Center in Florida checks a reading on the Dust Atmospheric Recovery Technology, or DART, spacecraft inside a laboratory at the Space Life Sciences Lab. DART will characterize the dust loading and microbial diversity in the atmosphere over Florida during summer months with a special emphasis on their interactions during an African dust storm. DART will be used to collect atmospheric aerosols and suspended microbial cells over Florida and Kennedy. Results will help predict the risks of excessive microbial contamination adhering to spacecraft surfaces. Photo credit: NASA/Dimitri Gerondidakis

KSC-2014-4901

NASA Image and Video Library

2014-10-31

CAPE CANAVERAL, Fla. – A researcher at NASA’s Kennedy Space Center in Florida checks a reading on the Dust Atmospheric Recovery Technology, or DART, spacecraft inside a laboratory at the Space Life Sciences Lab. DART will characterize the dust loading and microbial diversity in the atmosphere over Florida during summer months with a special emphasis on their interactions during an African dust storm. DART will be used to collect atmospheric aerosols and suspended microbial cells over Florida and Kennedy. Results will help predict the risks of excessive microbial contamination adhering to spacecraft surfaces. Photo credit: NASA/Dimitri Gerondidakis

KSC-2014-4903

NASA Image and Video Library

2014-10-31

CAPE CANAVERAL, Fla. – Researchers at NASA’s Kennedy Space Center in Florida check readings on the Dust Atmospheric Recovery Technology, or DART, spacecraft inside a laboratory at the Space Life Sciences Lab. DART will characterize the dust loading and microbial diversity in the atmosphere over Florida during summer months with a special emphasis on their interactions during an African dust storm. DART will be used to collect atmospheric aerosols and suspended microbial cells over Florida and Kennedy. Results will help predict the risks of excessive microbial contamination adhering to spacecraft surfaces. Photo credit: NASA/Dimitri Gerondidakis

KSC-2014-4902

NASA Image and Video Library

2014-10-31

CAPE CANAVERAL, Fla. – Researchers at NASA’s Kennedy Space Center in Florida check readings on the Dust Atmospheric Recovery Technology, or DART, spacecraft inside a laboratory at the Space Life Sciences Lab. DART will characterize the dust loading and microbial diversity in the atmosphere over Florida during summer months with a special emphasis on their interactions during an African dust storm. DART will be used to collect atmospheric aerosols and suspended microbial cells over Florida and Kennedy. Results will help predict the risks of excessive microbial contamination adhering to spacecraft surfaces. Photo credit: NASA/Dimitri Gerondidakis

KSC-2014-4899

NASA Image and Video Library

2014-10-31

CAPE CANAVERAL, Fla. – The Dust Atmospheric Recovery Technology, or DART, spacecraft is being assembled in a laboratory inside the Space Life Sciences Lab at NASA’s Kennedy Space Center in Florida. DART will characterize the dust loading and microbial diversity in the atmosphere over Florida during summer months with a special emphasis on their interactions during an African dust storm. DART will be used to collect atmospheric aerosols and suspended microbial cells over Florida and Kennedy. Results will help predict the risks of excessive microbial contamination adhering to spacecraft surfaces. Photo credit: NASA/Dimitri Gerondidakis

KSC-2014-4898

NASA Image and Video Library

2014-10-31

CAPE CANAVERAL, Fla. – The Dust Atmospheric Recovery Technology, or DART, spacecraft is being assembled in a laboratory inside the Space Life Sciences Lab at NASA’s Kennedy Space Center in Florida. DART will characterize the dust loading and microbial diversity in the atmosphere over Florida during summer months with a special emphasis on their interactions during an African dust storm. DART will be used to collect atmospheric aerosols and suspended microbial cells over Florida and Kennedy. Results will help predict the risks of excessive microbial contamination adhering to spacecraft surfaces. Photo credit: NASA/Dimitri Gerondidakis

DART Employees at Work

NASA Image and Video Library

2014-10-31

A researcher from the University of Florida in Gainesville, checks the Dust Atmospheric Recovery Technology, or DART, spacecraft in a laboratory inside the Space Life Sciences Lab at NASA’s Kennedy Space Center in Florida. DART will characterize the dust loading and microbial diversity in the atmosphere over Florida during summer months with a special emphasis on their interactions during an African dust storm. DART will be used to collect atmospheric aerosols and suspended microbial cells over Florida and Kennedy. Results will help predict the risks of excessive microbial contamination adhering to spacecraft surfaces.

NUTRIENT LOADING EFFECTS ON BIOGEOCHEMICAL AND MICROBIAL PROCESSES IN A NEW ENGLAND HIGH SALT MARCH (SPARTINA PATENS)

EPA Science Inventory

An ever-increasing population in the coastal zone has led to increased nutrient loading to estuaries worldwide. Marshes represent an important transitional zone between uplands and estuaries and can intercept nutrient inputs from uplands. We examined the effects of N and P fertil...

EFFECTS OF NUTRIENT LOADING ON BIOGEOCHEMICAL AND MICROBIAL PROCESSES IN A NEW ENGLAND HIGH SALT MARCH (SPARTINA PATENS)

EPA Science Inventory

An ever-increasing population in the coastal zone has led to increased nutrient loading to estuaries worldwide. Marshes represent an important transitional zone between uplands and estuaries and can intercept nutrient inputs from uplands. We examined the effects of N and P fertil...

Microbial Community in a Biofilter for Removal of Low Load Nitrobenzene Waste Gas

PubMed Central

Zhai, Jian; Wang, Zhu; Shi, Peng; Long, Chao

2017-01-01

To improve biofilter performance, the microbial community of a biofilter must be clearly defined. In this study, the performance of a lab-scale polyurethane biofilter for treating waste gas with low loads of nitrobenzene (NB) (< 20 g m-3 h-1) was investigated when using different empty bed residence times (EBRT) (64, 55.4 and 34 s, respectively). In addition, the variations of the bacterial community in the biofilm on the longitudinal distribution of the biofilters were analysed by using Illumina MiSeq high-throughput sequencing. The results showed that NB waste gas was successfully degraded in the biofilter. High-throughput sequencing data suggested that the phylum Actinobacteria and genus Rhodococcus played important roles in the degradation of NB. The variations of the microbial community were attributed to the different intermediate degradation products of NB in each layer. The strains identified in this study were potential candidates for purifying waste gas effluents containing NB. PMID:28114416

Effects of organic loading rates on reactor performance and microbial community changes during thermophilic aerobic digestion process of high-strength food wastewater.

PubMed

Jang, Hyun Min; Lee, Jae Won; Ha, Jeong Hyub; Park, Jong Moon

2013-11-01

To evaluate the applicability of single-stage thermophilic aerobic digestion (TAD) process treating high-strength food wastewater (FWW), TAD process was operated at four organic loading rates (OLRs) from 9.2 to 37.2 kg COD/m(3)d. The effects of OLRs on microbial community changes were also examined. The highest volumetric removal rate (13.3 kg COD/m(3)d) and the highest thermo-stable protease activity (0.95 unit/mL) were detected at OLR=18.6 kg COD/m(3)d. Denaturing gradient gel electrophoresis (DGGE) profiles and quantitative PCR (qPCR) results showed significant microbial community shifts in response to changes in OLR. In particular, DGGE and phylogenetic analysis demonstrate that the presence of Bacillus sp. (phylum of Firmicutes) was strongly correlated with efficient removal of organic particulates from high-strength food wastewater. Copyright © 2013 Elsevier Ltd. All rights reserved.

Microbial community structure and dynamics in a mixotrophic nitrogen removal process using recycled spent caustic under different loading conditions.

PubMed

Park, Sora; Yu, Jaecheul; Byun, Imgyu; Cho, Sunja; Park, Taejoo; Lee, Taeho

2011-08-01

A laboratory-scale Bardenpho process was established to investigate the proper nitrogen loading rate (NLR) when modified spent caustic (MSC) is applied as electron donor and alkalinity source for denitrification. MSC injection induced autotrophic nitrogen removal with sulfur as electron donor and heterotrophic denitrification. The nitrogen removal rate (NRR) did not increase proportionally to NLR. Based on the total nitrogen concentration in the effluent observed in the trials with MSC, the NLR in the influent should not exceed 0.15 kg N/m(3)d in order to satisfy water quality regulations. Microbial communities in the anoxic reactors were characterized by pyrosequencing of 16S rRNA gene sequences amplified by the polymerase chain reaction of DNA extracted from sludge samples. Microbial diversity was lower as MSC dosage was increased, and the injection of MSC caused an increase in SOB belonging to the genus Thiobacillus which is responsible for denitrification using sulfur. Copyright © 2011 Elsevier Ltd. All rights reserved.

Cleaning frequency and the microbial load in ice-cream.

PubMed

Holm, Sonya; Toma, Ramses B; Reiboldt, Wendy; Newcomer, Chris; Calicchia, Melissa

2002-07-01

This study investigates the efficacy of a 62 h cleaning frequency in the manufacturing of ice-cream. Various product and product contact surfaces were sampled progressively throughout the time period between cleaning cycles, and analyzed for microbial growth. The coliform and standard plate counts (SPC) of these samples did not vary significantly over time after 0, 24, 48, or 62 h from Cleaning in Place (CiP). Data for product contact surfaces were significant for the SPC representing sample locations. Some of the variables in cleaning practices had significant influence on microbial loads. An increase in the number of flavors manufactured caused a decrease in SPC within the 24 h interval, but by the 48 h interval the SPC increased. More washouts within the first 24 h interval were favorable, as indicated by decreased SPC. The more frequently the liquefier was sanitized within the 62 h interval, the lower the SPC. This study indicates that food safety was not compromised and safety practices were effectively implemented throughout the process.

Insights into biomethane production and microbial community succession during semi-continuous anaerobic digestion of waste cooking oil under different organic loading rates.

PubMed

He, Jing; Wang, Xing; Yin, Xiao-Bo; Li, Qiang; Li, Xia; Zhang, Yun-Fei; Deng, Yu

2018-06-01

High content of lipids in food waste could restrict digestion rate and give rise to the accumulation of long chain fatty acids in anaerobic digester. In the present study, using waste cooking oil skimmed from food waste as the sole carbon source, the effect of organic loading rate (OLR) on the methane production and microbial community dynamics were well investigated. Results showed that stable biomethane production was obtained at an organic loading rate of 0.5-1.5 g VS L -1  days -1 . The specific biogas/methane yield values at OLR of 1.0 were 1.44 ± 0.15 and 0.98 ± 0.11 L g VS -1 , respectively. The amplicon pyrosequencing revealed the distinct microbial succession in waste cooking oil AD reactors. Acetoclastic methanogens belonging to the genus Methanosaeta were the most dominant archaea, while the genera Syntrophomona, Anaerovibrio and Synergistaceae were the most common bacteria during AD process. Furthermore, redundancy analysis indicated that OLR showed more significant effect on the bacterial communities than that of archaeal communities. Additionally, whether the OLR of lipids increased had slight influence on the acetate fermentation pathway.

Can Particulate Air Sampling Predict Microbial Load in Operating Theatres for Arthroplasty?

PubMed Central

Cristina, Maria Luisa; Spagnolo, Anna Maria; Sartini, Marina; Panatto, Donatella; Gasparini, Roberto; Orlando, Paolo; Ottria, Gianluca; Perdelli, Fernanda

2012-01-01

Several studies have proposed that the microbiological quality of the air in operating theatres be indirectly evaluated by means of particle counting, a technique derived from industrial clean-room technology standards, using airborne particle concentration as an index of microbial contamination. However, the relationship between particle counting and microbiological sampling has rarely been evaluated and demonstrated in operating theatres. The aim of the present study was to determine whether particle counting could predict microbiological contamination of the air in an operating theatre during 95 surgical arthroplasty procedures. This investigation was carried out over a period of three months in 2010 in an orthopedic operating theatre devoted exclusively to prosthetic surgery. During each procedure, the bacterial contamination of the air was determined by means of active sampling; at the same time, airborne particulate contamination was assessed throughout the entire procedure. On considering the total number of surgical operations, the mean value of the total bacterial load in the center of the operating theatre proved to be 35 CFU/m3; the mean particle count was 4,194,569 no./m3 for particles of diameter ≥0.5 µm and 13,519 no./m3 for particles of diameter ≥5 µm. No significant differences emerged between the median values of the airborne microbial load recorded during the two types of procedure monitored. Particulates with a diameter of ≥0.5 µm were detected in statistically higher concentrations (p<0.001) during knee-replacement procedures. By contrast, particulates with a diameter of ≥5 µm displayed a statistically higher concentration during hip-replacement procedures (p<0.05). The results did not reveal any statistically significant correlation between microbial loads and particle counts for either of the particle diameters considered (≥0.5 µm and ≥5 µm). Consequently, microbiological monitoring remains the most suitable method of evaluating the quality of air in operating theatres. PMID:23285189

Can particulate air sampling predict microbial load in operating theatres for arthroplasty?

PubMed

Cristina, Maria Luisa; Spagnolo, Anna Maria; Sartini, Marina; Panatto, Donatella; Gasparini, Roberto; Orlando, Paolo; Ottria, Gianluca; Perdelli, Fernanda

2012-01-01

Several studies have proposed that the microbiological quality of the air in operating theatres be indirectly evaluated by means of particle counting, a technique derived from industrial clean-room technology standards, using airborne particle concentration as an index of microbial contamination. However, the relationship between particle counting and microbiological sampling has rarely been evaluated and demonstrated in operating theatres. The aim of the present study was to determine whether particle counting could predict microbiological contamination of the air in an operating theatre during 95 surgical arthroplasty procedures. This investigation was carried out over a period of three months in 2010 in an orthopedic operating theatre devoted exclusively to prosthetic surgery. During each procedure, the bacterial contamination of the air was determined by means of active sampling; at the same time, airborne particulate contamination was assessed throughout the entire procedure. On considering the total number of surgical operations, the mean value of the total bacterial load in the center of the operating theatre proved to be 35 CFU/m(3); the mean particle count was 4,194,569 no./m(3) for particles of diameter ≥0.5 µm and 13,519 no./m(3) for particles of diameter ≥5 µm. No significant differences emerged between the median values of the airborne microbial load recorded during the two types of procedure monitored. Particulates with a diameter of ≥0.5 µm were detected in statistically higher concentrations (p<0.001) during knee-replacement procedures. By contrast, particulates with a diameter of ≥5 µm displayed a statistically higher concentration during hip-replacement procedures (p<0.05). The results did not reveal any statistically significant correlation between microbial loads and particle counts for either of the particle diameters considered (≥0.5 µm and ≥5 µm). Consequently, microbiological monitoring remains the most suitable method of evaluating the quality of air in operating theatres.

Effects of combination of ultraviolet light and hydrogen peroxide on inactivation of Escherichia coli O157:H7, native microbial loads, and quality of button mushrooms

USDA-ARS?s Scientific Manuscript database

Mushrooms are prone to microbial spoilage and browning during growing and processing. Ultraviolet light (UV-C) has been used as an alternative technology to chemical sanitizers for food products. Hydrogen peroxide is classified as generally recognized as safe for use in foods as a bleaching and ant...

Functional Responses of Salt Marsh Microbial Communities to Long-Term Nutrient Enrichment

PubMed Central

Graves, Christopher J.; Makrides, Elizabeth J.; Schmidt, Victor T.; Giblin, Anne E.; Cardon, Zoe G.

2016-01-01

ABSTRACT Environmental nutrient enrichment from human agricultural and waste runoff could cause changes to microbial communities that allow them to capitalize on newly available resources. Currently, the response of microbial communities to nutrient enrichment remains poorly understood, and, while some studies have shown no clear changes in community composition in response to heavy nutrient loading, others targeting specific genes have demonstrated clear impacts. In this study, we compared functional metagenomic profiles from sediment samples taken along two salt marsh creeks, one of which was exposed for more than 40 years to treated sewage effluent at its head. We identified strong and consistent increases in the relative abundance of microbial genes related to each of the biochemical steps in the denitrification pathway at enriched sites. Despite fine-scale local increases in the abundance of denitrification-related genes, the overall community structures based on broadly defined functional groups and taxonomic annotations were similar and varied with other environmental factors, such as salinity, which were common to both creeks. Homology-based taxonomic assignments of nitrous oxide reductase sequences in our data show that increases are spread over a broad taxonomic range, thus limiting detection from taxonomic data alone. Together, these results illustrate a functionally targeted yet taxonomically broad response of microbial communities to anthropogenic nutrient loading, indicating some resolution to the apparently conflicting results of existing studies on the impacts of nutrient loading in sediment communities. IMPORTANCE In this study, we used environmental metagenomics to assess the response of microbial communities in estuarine sediments to long-term, nutrient-rich sewage effluent exposure. Unlike previous studies, which have mainly characterized communities based on taxonomic data or primer-based amplification of specific target genes, our whole-genome metagenomics approach allowed an unbiased assessment of the abundance of denitrification-related genes across the entire community. We identified strong and consistent increases in the relative abundance of gene sequences related to denitrification pathways across a broad phylogenetic range at sites exposed to long-term nutrient addition. While further work is needed to determine the consequences of these community responses in regulating environmental nutrient cycles, the increased abundance of bacteria harboring denitrification genes suggests that such processes may be locally upregulated. In addition, our results illustrate how whole-genome metagenomics combined with targeted hypothesis testing can reveal fine-scale responses of microbial communities to environmental disturbance. PMID:26944843

Functional Responses of Salt Marsh Microbial Communities to Long-Term Nutrient Enrichment.

PubMed

Graves, Christopher J; Makrides, Elizabeth J; Schmidt, Victor T; Giblin, Anne E; Cardon, Zoe G; Rand, David M

2016-05-01

Environmental nutrient enrichment from human agricultural and waste runoff could cause changes to microbial communities that allow them to capitalize on newly available resources. Currently, the response of microbial communities to nutrient enrichment remains poorly understood, and, while some studies have shown no clear changes in community composition in response to heavy nutrient loading, others targeting specific genes have demonstrated clear impacts. In this study, we compared functional metagenomic profiles from sediment samples taken along two salt marsh creeks, one of which was exposed for more than 40 years to treated sewage effluent at its head. We identified strong and consistent increases in the relative abundance of microbial genes related to each of the biochemical steps in the denitrification pathway at enriched sites. Despite fine-scale local increases in the abundance of denitrification-related genes, the overall community structures based on broadly defined functional groups and taxonomic annotations were similar and varied with other environmental factors, such as salinity, which were common to both creeks. Homology-based taxonomic assignments of nitrous oxide reductase sequences in our data show that increases are spread over a broad taxonomic range, thus limiting detection from taxonomic data alone. Together, these results illustrate a functionally targeted yet taxonomically broad response of microbial communities to anthropogenic nutrient loading, indicating some resolution to the apparently conflicting results of existing studies on the impacts of nutrient loading in sediment communities. In this study, we used environmental metagenomics to assess the response of microbial communities in estuarine sediments to long-term, nutrient-rich sewage effluent exposure. Unlike previous studies, which have mainly characterized communities based on taxonomic data or primer-based amplification of specific target genes, our whole-genome metagenomics approach allowed an unbiased assessment of the abundance of denitrification-related genes across the entire community. We identified strong and consistent increases in the relative abundance of gene sequences related to denitrification pathways across a broad phylogenetic range at sites exposed to long-term nutrient addition. While further work is needed to determine the consequences of these community responses in regulating environmental nutrient cycles, the increased abundance of bacteria harboring denitrification genes suggests that such processes may be locally upregulated. In addition, our results illustrate how whole-genome metagenomics combined with targeted hypothesis testing can reveal fine-scale responses of microbial communities to environmental disturbance. Copyright © 2016 Graves et al.

Bioremediation of diesel oil in a co-contaminated soil by bioaugmentation with a microbial formula tailored with native strains selected for heavy metals resistance.

PubMed

Alisi, Chiara; Musella, Rosario; Tasso, Flavia; Ubaldi, Carla; Manzo, Sonia; Cremisini, Carlo; Sprocati, Anna Rosa

2009-04-01

The aim of the work is to assess the feasibility of bioremediation of a soil, containing heavy metals and spiked with diesel oil (DO), through a bioaugmentation strategy based on the use of a microbial formula tailored with selected native strains. The soil originated from the metallurgic area of Bagnoli (Naples, Italy). The formula, named ENEA-LAM, combines ten bacterial strains selected for multiple resistance to heavy metals among the native microbial community. The biodegradation process of diesel oil was assessed in biometer flasks by monitoring the following parameters: DO composition by GC-MS, CO2 evolution rate, microbial load and composition of the community by T-RFLP, physiological profile in Biolog ECOplates and ecotoxicity of the system. The application of this microbial formula allowed to obtain, in the presence of heavy metals, the complete degradation of n-C(12-20), the total disappearance of phenantrene, a 60% reduction of isoprenoids and an overall reduction of about 75% of the total diesel hydrocarbons in 42 days. Concurrently with the increase of metabolic activity at community level and the microbial load, the gradual abatement of the ecotoxicity was observed. The T-RFLP analysis highlighted that most of the ENEA-LAM strains survived and some minor native strains, undetectable in the soil at the beginning of the experiment, developed. Such a bioaugmentation approach allows the newly established microbial community to strike a balance between the introduced and the naturally present microorganisms. The results indicate that the use of a tailored microbial formula may efficiently facilitate and speed up the bioremediation of matrices co-contaminated with hydrocarbons and heavy metals. The study represents the first step for the scale up of the system and should be verified at a larger scale. In this view, this bioaugmentation strategy may contribute to overcome a critical bottleneck of the bioremediation technology.

Effect of different film packaging on microbial growth in minimally processed cactus pear (Opuntia ficus-indica).

PubMed

Palma, A; Mangia, N P; Fadda, A; Barberis, A; Schirra, M; D'Aquino, S

2013-01-01

Microorganisms are natural contaminants of fresh produce and minimally processed products, and contamination arises from a number of sources, including the environment, postharvest handling and processing. Fresh-cut products are particularly susceptible to microbial contaminations because of the changes occurring in the tissues during processing. In package gas composition of modified atmosphere packaging (MAP) in combination with low storage temperatures besides reducing physiological activity of packaged produce, can also delay pathogen growth. Present study investigated on the effect of MAPs, achieved with different plastic films, on microbial growth of minimally processed cactus pear (Opuntio ficus-indica) fruit. Five different plastic materials were used for packaging the manually peeled fruit. That is: a) polypropylene film (Termoplast MY 40 micron thickness, O2 transmission rate 300 cc/m2/24h); b) polyethylene film (Bolphane BHE, 11 micron thickness, O2 transmission rate 19000 cc/m2/24h); c) polypropylene laser-perforated films (Mach Packaging) with 8, 16 or 32 100-micron holes. Total aerobic psychrophilic, mesophilic microorganisms, Enterobacteriaceae, yeast, mould populations and in-package CO2, O2 and C2H4 were determined at each storage time. Different final gas compositions, ranging from 7.8 KPa to 17.1 KPa O2, and 12.7 KPa to 2.6 KPa CO2, were achieved with MY and micro perforated films, respectively. Differences were detected in the mesophilic, Enterobacteriaceae and yeast loads, while no difference was detected in psychrophilic microorganisms. At the end of storage, microbial load in fruits sealed with MY film was significantly lower than in those sealed with BHE and micro perforated films. Furthermore, fruits packed with micro-perforated films showed the highest microbial load. This occurrence may in part be related to in-package gas composition and in part to a continuous contamination of microorganisms through micro-holes.

Microbial Load of Hard Red Winter Wheat Produced at Three Growing Environments across Nebraska, USA.

PubMed

Sabillón, Luis; Stratton, Jayne; Rose, Devin J; Regassa, Teshome H; Bianchini, Andréia

2016-04-01

Post-flowering weather variables in farm fields may influence the microbial loads of wheat grain. In this study, the effects of weather variables following wheat flowering on the microbiological quality of wheat were evaluated over two consecutive growing seasons (2011 to 2012 and 2012 to 2013) in the state of Nebraska, USA. Three hard red winter wheat lines, including two commercial cultivars (Overland and McGill) and one experimental line (NW07505), were planted in three regions with contrasting key weather variables (Southeast, South Central, and Panhandle district) to ensure that developing seeds were exposed to different weather conditions. The natural microbial flora and deoxynivalenol concentrations of 54 freshly harvested wheat samples (three samples per wheat line, with a total of 9 samples per district) were analyzed to evaluate the impacts of the weather conditions prevailing from flowering to harvesting in each growing location (district) and season on the microbiological quality and safety of wheat grain. In 2012, the values for aerobic plate counts, Enterobacteriaceae, yeasts, molds, and internal mold infection levels were significantly lower in grain samples collected from the Panhandle district than in grain harvested from the South Central and Southeastern districts. No significant differences in the yeast counts were found in grain collected from all districts in 2013, but the levels of internal mold infection and mold counts were significantly higher in grain from the Southeastern district than in grain from the Panhandle district. Deoxynivalenol was detected in all districts; however, the concentrations were below the advisory level of 1 mg/kg for processed wheat. Microbial growth during grain development seems to be dependent on the existence of a threshold level of weather variables during the season. In general, the microbial loads in wheat grain tended to be lower in those areas with lower relative humidity levels (below 55%) and with temperatures lower than 13.7°C and higher than 31.5°C.

Metaproteomics Reveals Functional Shifts in Microbial and Human Proteins During Infant Gut Colonization Case

DOE PAGES

Young, Jacque C.; Pan, Chongle; Adams, Rachel M.; ...

2015-01-01

The microbial colonization of the human gastrointestinal tract plays an important role in establishing health and homeostasis. However, the time-dependent functional signatures of microbial and human proteins during early colonization of the gut have yet to be determined. Thus, we employed shotgun proteomics to simultaneously monitor microbial and human proteins in fecal samples from a preterm infant during the first month of life. Microbial community complexity and functions increased over time, with compositional changes that were consistent with previous metagenomic and rRNA gene data indicating three distinct colonization phases. Overall microbial community functions were established relatively early in development andmore » remained stable. Human proteins detected included those responsible for epithelial barrier function and antimicrobial activity. Some neutrophil-derived proteins increased in abundance early in the study period, suggesting activation of the innate immune system. Moreover, abundances of cytoskeletal and mucin proteins increased later in the time course, suggestive of subsequent adjustment to the increased microbial load. Our study provides the first snapshot of coordinated human and microbial protein expression in the infant gut during early development.« less

KSC-2014-4904

NASA Image and Video Library

2014-10-31

CAPE CANAVERAL, Fla. – A researcher from the University of Florida in Gainesville, checks the Dust Atmospheric Recovery Technology, or DART, spacecraft in a laboratory inside the Space Life Sciences Lab at NASA’s Kennedy Space Center in Florida. DART will characterize the dust loading and microbial diversity in the atmosphere over Florida during summer months with a special emphasis on their interactions during an African dust storm. DART will be used to collect atmospheric aerosols and suspended microbial cells over Florida and Kennedy. Results will help predict the risks of excessive microbial contamination adhering to spacecraft surfaces. Photo credit: NASA/Dimitri Gerondidakis

Sulfur and Methylmercury in the Florida Everglades - the Biogeochemical Connection

NASA Astrophysics Data System (ADS)

Orem, W. H.; Gilmour, C. C.; Krabbenhoft, D. P.; Aiken, G.

2011-12-01

Methylmercury (MeHg) is a serious environmental problem in aquatic ecosystems worldwide because of its toxicity and tendency to bioaccumulate. The Everglades receives some of the highest levels of atmospheric mercury deposition and has some of the highest levels of MeHg in fish in the USA, posing a threat to pisciverous wildlife and people through fish consumption. USGS studies show that a combination of biogeochemical factors make the Everglades especially susceptible to MeHg production and bioaccumulation: (1) vast wetland area with anoxic soils supporting anaerobic microbial activity, (2) high rates of atmospheric mercury deposition, (3) high levels of dissolved organic carbon (DOC) that complexes and stabilizes mercury in solution for transport to sites of methylation, and (4) high sulfate loading in surface water that drives microbial sulfate reduction and mercury methylation. The high levels of sulfate in the Everglades represent an unnatural condition. Background sulfate levels are estimated to be <1 mg/L, but about 60% of the Everglades has surface water sulfate concentrations exceeding background. Highly sulfate-enriched marshes in the northern Everglades have average sulfate levels of 60 mg/L. Sulfate loading to the Everglades is principally a result of land and water management in south Florida. The highest concentrations of sulfate, averaging 60-70 mg/L, are in canal water in the Everglades Agricultural Area (EAA). Geochemical data and a preliminary sulfur mass balance for the EAA are consistent with sulfur currently used in agriculture, and sulfur released by oxidation of organic EAA soils (including legacy agricultural applications and natural sulfur) as the primary sources of sulfate enrichment to the canals and ecosystem. Sulfate loading increases microbial sulfate reduction and MeHg production in soils. The relationship between sulfate loading and MeHg production, however, is complex. Sulfate levels up to about 20-30 mg/L increase mercury methylation, but buildup of sulfide from microbial sulfate reduction begins to inhibit mercury methylation above this range. Sulfate from the EAA canals has primarily impacted the northern Everglades nearest the EAA, but recent evidence shows sulfate loading extending about 80 km further south into Everglades National Park. Current restoration plans to restore to deliver more water south to Everglades National Park may increase overall sulfur loads to the southern part of the ecosystem. A comprehensive Everglades restoration strategy should include reduction of sulfur loads as a goal because of the many detrimental impacts of sulfate on the ecosystem. Monitoring data show that the ecosystem response to changes in sulfate levels is rapid, and strategies for reducing sulfate loading may be effective in the near-term. A multifaceted approach employing best management practices for sulfur in agriculture, agricultural practices that minimize soil oxidation, and changes to stormwater treatment areas that increase sulfate retention, could help reduce sulfate loads to the Everglades, with resulting benefits.

Power generation in microbial fuel cells using platinum group metal-free cathode catalyst: Effect of the catalyst loading on performance and costs.

PubMed

Santoro, Carlo; Kodali, Mounika; Herrera, Sergio; Serov, Alexey; Ieropoulos, Ioannis; Atanassov, Plamen

2018-02-28

Platinum group metal-free (PGM-free) catalyst with different loadings was investigated in air breathing electrodes microbial fuel cells (MFCs). Firstly, the electrocatalytic activity towards oxygen reduction reaction (ORR) of the catalyst was investigated by rotating ring disk electrode (RRDE) setup with different catalyst loadings. The results showed that higher loading led to an increased in the half wave potential and the limiting current and to a further decrease in the peroxide production. The electrons transferred also slightly increased with the catalyst loading up to the value of ≈3.75. This variation probably indicates that the catalyst investigated follow a 2x2e - transfer mechanism. The catalyst was integrated within activated carbon pellet-like air-breathing cathode in eight different loadings varying between 0.1 mgcm -2 and 10 mgcm -2 . Performance were enhanced gradually with the increase in catalyst content. Power densities varied between 90 ± 9 μWcm -2 and 262 ± 4 μWcm -2 with catalyst loading of 0.1 mgcm -2 and 10 mgcm -2 respectively. Cost assessments related to the catalyst performance are presented. An increase in catalyst utilization led to an increase in power generated with a substantial increase in the whole costs. Also a decrease in performance due to cathode/catalyst deterioration over time led to a further increase in the costs.

Deposition and postdeposition mechanisms as possible drivers of microbial population variability in glacier ice.

PubMed

Xiang, Shu-Rong; Shang, Tian-Cui; Chen, Yong; Yao, Tan-Dong

2009-11-01

Glaciers accumulate airborne microorganisms year by year and thus are good archives of microbial communities and their relationship to climatic and environmental changes. Hypotheses have focused on two possible drivers of microbial community composition in glacier systems. One is aeolian deposition, in which the microbial load by aerosol, dust, and precipitation events directly determines the amount and composition of microbial species in glacier ice. The other is postdepositional selection, in which the metabolic activity in surface snow causes microbial community shifts in glacier ice. An additional possibility is that both processes occur simultaneously. Aeolian deposition initially establishes a microbial community in the ice, whereas postdeposition selection strengthens the deposition patterns of microorganisms with the development of tolerant species in surface snow, resulting in varying structures of microbial communities with depth. In this minireview, we examine these postulations through an analysis of physical-chemical and biological parameters from the Malan and Vostok ice cores, and the Kuytun 51 Glacial surface and deep snow. We discuss these and other recent results in the context of the hypothesized mechanisms driving microbial community succession in glaciers. We explore our current gaps in knowledge and point out future directions for research on microorganisms in glacial ecosystems.

Preparing for the crewed Mars journey: microbiota dynamics in the confined Mars500 habitat during simulated Mars flight and landing.

PubMed

Schwendner, Petra; Mahnert, Alexander; Koskinen, Kaisa; Moissl-Eichinger, Christine; Barczyk, Simon; Wirth, Reinhard; Berg, Gabriele; Rettberg, Petra

2017-10-04

The Mars500 project was conceived as the first full duration simulation of a crewed return flight to Mars. For 520 days, six crew members lived confined in a specifically designed spacecraft mock-up. The herein described "MIcrobial ecology of Confined Habitats and humAn health" (MICHA) experiment was implemented to acquire comprehensive microbiota data from this unique, confined manned habitat, to retrieve important information on the occurring microbiota dynamics, the microbial load and diversity in the air and on various surfaces. In total, 360 samples from 20 (9 air, 11 surface) locations were taken at 18 time-points and processed by extensive cultivation, PhyloChip and next generation sequencing (NGS) of 16S rRNA gene amplicons. Cultivation assays revealed a Staphylococcus and Bacillus-dominated microbial community on various surfaces, with an average microbial load that did not exceed the allowed limits for ISS in-flight requirements indicating adequate maintenance of the facility. Areas with high human activity were identified as hotspots for microbial accumulation. Despite substantial fluctuation with respect to microbial diversity and abundance throughout the experiment, the location within the facility and the confinement duration were identified as factors significantly shaping the microbial diversity and composition, with the crew representing the main source for microbial dispersal. Opportunistic pathogens, stress-tolerant or potentially mobile element-bearing microorganisms were predicted to be prevalent throughout the confinement, while the overall microbial diversity dropped significantly over time. Our findings clearly indicate that under confined conditions, the community structure remains a highly dynamic system which adapts to the prevailing habitat and micro-conditions. Since a sterile environment is not achievable, these dynamics need to be monitored to avoid spreading of highly resistant or potentially pathogenic microorganisms and a potentially harmful decrease of microbial diversity. If necessary, countermeasures are required, to maintain a healthy, diverse balance of beneficial, neutral and opportunistic pathogenic microorganisms. Our results serve as an important data collection for (i) future risk estimations of crewed space flight, (ii) an optimized design and planning of a spacecraft mission and (iii) for the selection of appropriate microbial monitoring approaches and potential countermeasures, to ensure a microbiologically safe space-flight environment.

Physico-Chemical and Microbial Analysis of Selected Borehole Water in Mahikeng, South Africa.

PubMed

Palamuleni, Lobina; Akoth, Mercy

2015-07-23

Groundwater is generally considered a "safe source" of drinking water because it is abstracted with low microbial load with little need for treatment before drinking. However, groundwater resources are commonly vulnerable to pollution, which may degrade their quality. An assessment of microbial and physicochemical qualities of borehole water in the rural environs of Mahikeng town, South Africa, was carried out. The study aimed at determining levels of physicochemical (temperature, pH, turbidity and nitrate) and bacteriological (both faecal and total coliform bacteria) contaminants in drinking water using standard microbiology methods. Furthermore, identities of isolates were determined using the API 20E assay. Results were compared with World Health Organisation (WHO) and Department of Water Affairs (DWAF-SA) water quality drinking standards. All analyses for physicochemical parameters were within acceptable limits except for turbidity while microbial loads during spring were higher than the WHO and DWAF thresholds. The detection of Escherichia coli, Salmonella and Klebsiella species in borehole water that was intended for human consumption suggests that water from these sources may pose severe health risks to consumers and is unsuitable for direct human consumption without treatment. The study recommends mobilisation of onsite treatment interventions to protect the households from further possible consequences of using the water.

PubMed Central

CRISTINA, M.L.; SCHINCA, E.; OTTRIA, G.; SPAGNOLO, A.M.

2016-01-01

Summary Background. The rate of surgical site infections (SSI) is strongly influenced by operating room quality, which is determined by the structural features of the facility and its systems and by the management and behavior of healthcare workers. The aim of the present study was to assess microbial contamination in the operating room during hip- and knee-replacement procedures, the behavior of operating room staff and the incidence of SSI through postdischarge surveillance. Methods. Microbial contamination was evaluated by active and passive sampling at rest and in operating conditions. Organizational and behavioral characteristics were collected through observational assessment. The incidence of SSI was evaluated in 255 patients, and follow-up examinations were carried out 30 and 365 days after the procedure. Results. The mean values of the airborne and sedimenting microbial loads were 12.90 CFU/m3 and 0.02 CFU/cm2/h, respectively. With regard to outcome, the infection rate proved to be 0.89% and was associated with knee-replacement procedures. The microorganism responsible for this superficial infection was Staphylococcus aureus. Conclusions. Clinical outcomes proved to be satisfactory, owing to the limited microbial load (in both at-rest and operating conditions), the appropriate behavior of the staff, compliance with the guidelines on preoperative antibiotic prophylaxis, and efficient management of the ventilation system. PMID:27980378

Operating room environment and surgical site infections in arthroplasty procedures.

PubMed

Cristina, M L; Sartini, M; Schinca, E; Ottria, G; Spagnolo, A M

2016-09-01

The rate of surgical site infections (SSI) is strongly influenced by operating room quality, which is determined by the structural features of the facility and its systems and by the management and behavior of healthcare workers. The aim of the present study was to assess microbial contamination in the operating room during hip- and knee-replacement procedures, the behavior of operating room staff and the incidence of SSI through postdischarge surveillance. Microbial contamination was evaluated by active and passive sampling at rest and in operating conditions. Organizational and behavioral characteristics were collected through observational assessment. The incidence of SSI was evaluated in 255 patients, and follow-up examinations were carried out 30 and 365 days after the procedure. The mean values of the airborne and sedimenting microbial loads were 12.90 CFU/m 3 and 0.02 CFU/cm2/h, respectively. With regard to outcome, the infection rate proved to be 0.89% and was associated with knee-replacement procedures. The microorganism responsible for this superficial infection was Staphylococcus aureus. Clinical outcomes proved to be satisfactory, owing to the limited microbial load (in both at-rest and operating conditions), the appropriate behavior of the staff, compliance with the guidelines on preoperative antibiotic prophylaxis, and efficient management of the ventilation system.

Physico-Chemical and Microbial Analysis of Selected Borehole Water in Mahikeng, South Africa

PubMed Central

Palamuleni, Lobina; Akoth, Mercy

2015-01-01

Groundwater is generally considered a “safe source” of drinking water because it is abstracted with low microbial load with little need for treatment before drinking. However, groundwater resources are commonly vulnerable to pollution, which may degrade their quality. An assessment of microbial and physicochemical qualities of borehole water in the rural environs of Mahikeng town, South Africa, was carried out. The study aimed at determining levels of physicochemical (temperature, pH, turbidity and nitrate) and bacteriological (both faecal and total coliform bacteria) contaminants in drinking water using standard microbiology methods. Furthermore, identities of isolates were determined using the API 20E assay. Results were compared with World Health Organisation (WHO) and Department of Water Affairs (DWAF-SA) water quality drinking standards. All analyses for physicochemical parameters were within acceptable limits except for turbidity while microbial loads during spring were higher than the WHO and DWAF thresholds. The detection of Escherichia coli, Salmonella and Klebsiella species in borehole water that was intended for human consumption suggests that water from these sources may pose severe health risks to consumers and is unsuitable for direct human consumption without treatment. The study recommends mobilisation of onsite treatment interventions to protect the households from further possible consequences of using the water. PMID:26213950

Quantitative Analysis of Microbial Burden on Hospital Room Environmental Surfaces Contributing to Healthcare-Associated Infections

PubMed Central

Rutala, William A; Kanamori, Hajime; Gergen, Maria; Sickbert-Bennett, Emily; Knelson, Lauren P; Chen, Luke F; Anderson, Deverick; Sexton, Daniel; Weber, David J

2017-01-01

Abstract Background Contaminated environmental surfaces are involved in the transmission of epidemiologically important pathogens. It remains unknown which level of microbial load can contribute to healthcare-associated infections (HAI). We used microbiological data obtained from the Benefits of Enhanced Terminal Room (BETR) Disinfection Study to investigate the quantitative relationship between microbial burden and risk of HAI. Methods Microbiological samples were collected from high-frequency-touch hospital room surfaces using Rodac plates (25 cm2/plate) in rooms after terminal room disinfection. All rooms were randomly assigned to standard disinfection (Quaternary ammonium [Quat]) or an enhanced disinfection (Quat/ultraviolet light [UV-C], Bleach, Bleach/UV-C). The Quat/UV-C arm was excluded from further analysis since HAI were not observed in this arm. All new patients in study rooms were monitored for HAI following terminal disinfection through the BETR study standard protocols. We analyzed the relationship between the total colony forming units (CFU) of bacterial loads from 2,395 environmental samples in 60 rooms and HAI among new patients in the room (6 patients with HAI and 54 patients without HAI). Each arm had 2 patients with HAI. Statistical significance was determined by the Wilcoxon test, and P < 0.05 was considered significant. Results Overall, samples in rooms of patients with HAI had a mean 39.3 CFU, while samples from rooms of patients without HAI had a mean 35.6 CFU (Table 1). In the standard disinfection, the sampled rooms from the HAI patients had a significantly higher number of total CFU (mean 65.1 CFU) than non-HAI group (mean 35.5 CFU) (P = 0.019). In the enhanced disinfection rooms, there was no statistical significance between HAI and non-HAI groups. Conclusion Although our sample size may have been too small to detect contaminated microbial load in a room though a large clinical trial was conducted, our data based on the Quat arm as standard disinfection demonstrated the significant relationship between microbial load and HAI. Disclosures D. Sexton, Centers for Disease Control and Prevention: Grant Investigator, Grant recipient. Centers for Disease Control and Prevention Foundation: Grant Investigator, Grant recipient. UpToDate: Collaborator, Royalty Recipient. D. J. Weber, PDI: Consultant, Consulting fee

Effect of household cooking techniques on the microbiological load and the nutritional quality of mealworms (Tenebrio molitor L. 1758).

PubMed

Caparros Megido, Rudy; Poelaert, Christine; Ernens, Marjorie; Liotta, Marisa; Blecker, Christophe; Danthine, Sabine; Tyteca, Eva; Haubruge, Éric; Alabi, Taofic; Bindelle, Jérôme; Francis, Frédéric

2018-04-01

Mealworms are new food products in Europe, but consumers do not know how to cook them. Although cooking could increase the safety, acceptability, palatability, and digestibility of insects, the heating process could have deleterious effects on protein and lipid quality. Therefore, this study characterized the effects of different household cooking methods (boiling, pan-frying, vacuum cooking, and oven cooking) on the microbial load and nutritive value of mealworms, with a focus on protein digestibility and fatty acid composition. Boiling and cooking under vacuum were the most efficient techniques to reduce microbial load while maintaining the high levels of protein and polyunsaturated fatty acids of mealworms. Cooking method-related changes were very low on macronutrients content except for pan-fried mealworms which exhibited the highest lipid content. Cooking slightly changed fatty acid composition of mealworms by principally decreasing their level of saturated fatty acids but also increased the in vitro crude protein digestibility of mealworms. Copyright © 2018 Elsevier Ltd. All rights reserved.

The use of microbial-earthworm ecofilters for wastewater treatment with special attention to influencing factors in performance: A review.

PubMed

Jiang, Luhua; Liu, Yunguo; Hu, Xinjiang; Zeng, Guangming; Wang, Hui; Zhou, Lu; Tan, Xiaofei; Huang, Binyan; Liu, Shaobo; Liu, Simian

2016-01-01

With the unique advantages of lower operational and maintenance cost, the use of microbial-earthworm ecofilters (MEEs) for the wastewater treatment has been increasing rapidly in the recent years. This paper provided an overview of the research activities on the use of MEEs for removing pollutants from various wastewater throughout the world. However, the long-term effective treatment performance and sustainable operation of this system still remain a challenge since the treatment performance would be affected by design parameters, operational conditions, and environmental factors. In order to promote the treatment performance, therefore, this paper also provided and summarized the influencing factors of pollutants removal in MEEs. The design parameters and operational conditions of MEEs include earthworm species and load, filter media type, hydraulic loading rate, nutrient load, packing bed height, chemical factors and temperature. Lastly, this review highlighted the further research on these issues to improve performance and sustainability of MEEs. Copyright © 2015 Elsevier Ltd. All rights reserved.

Ulva biomass as a co-substrate for stable anaerobic digestion of spent coffee grounds in continuous mode.

PubMed

Kim, Jaai; Kim, Hakchan; Lee, Changsoo

2017-10-01

Ulva biomass was evaluated as a co-substrate for anaerobic digestion of spent coffee grounds at varying organic loads (0.7-1.6g chemical oxygen demand (COD)/Ld) and substrate compositions. Co-digestion with Ulva (25%, COD basis) proved beneficial for SCG biomethanation in both terms of process performance and stability. The beneficial effect is much more pronounced at higher organic and hydraulic loads, with the highest COD removal and methane yield being 51.8% and 0.19L/g COD fed, respectively. The reactor microbial community structure changed dynamically during the experiment, and a dominance shift from hydrogenotrophic to aceticlastic methanogens occurred with increase in organic loading rate. Network analysis provides a comprehensive view of the microbial interactions involved in the system and confirms a direct positive correlation between Ulva input and methane productivity. A group of populations, including Methanobacterium- and Methanoculleus-related methanogens, was identified as a possible indicator for monitoring the biomethanation performance. Copyright © 2017 Elsevier Ltd. All rights reserved.

Performance of anaerobic fluidized membrane bioreactors using effluents of microbial fuel cells treating domestic wastewater.

PubMed

Kim, Kyoung-Yeol; Yang, Wulin; Ye, Yaoli; LaBarge, Nicole; Logan, Bruce E

2016-05-01

Anaerobic fluidized membrane bioreactors (AFMBRs) have been mainly developed as a post-treatment process to produce high quality effluent with very low energy consumption. The performance of an AFMBR was examined using the effluent from a microbial fuel cell (MFC) treating domestic wastewater, as a function of AFMBR hydraulic retention times (HRTs) and organic matter loading rates. The MFC-AFMBR achieved 89 ± 3% removal of the chemical oxygen demand (COD), with an effluent of 36 ± 6 mg-COD/L over 112 days operation. The AFMBR had very stable operation, with no significant changes in COD removal efficiencies, for HRTs ranging from 1.2 to 3.8h, although the effluent COD concentration increased with organic loading. Transmembrane pressure (TMP) was low, and could be maintained below 0.12 bar through solids removal. This study proved that the AFMBR could be operated with a short HRT but a low COD loading rate was required to achieve low effluent COD. Copyright © 2016 Elsevier Ltd. All rights reserved.

Low Doses of Imatinib Induce Myelopoiesis and Enhance Host Anti-microbial Immunity

PubMed Central

Swimm, Alyson; Giver, Cynthia R.; Harris, Wayne A. C.; Laval, Julie; Napier, Brooke A.; Patel, Gopi; Crump, Ryan; Peng, Zhenghong; Bornmann, William; Pulendran, Bali; Buller, R. Mark; Weiss, David S.; Tirouvanziam, Rabindra; Waller, Edmund K.; Kalman, Daniel

2015-01-01

Imatinib mesylate (Gleevec) inhibits Abl1, c-Kit, and related protein tyrosine kinases (PTKs) and serves as a therapeutic for chronic myelogenous leukemia and gastrointestinal stromal tumors. Imatinib also has efficacy against various pathogens, including pathogenic mycobacteria, where it decreases bacterial load in mice, albeit at doses below those used for treating cancer. We report that imatinib at such low doses unexpectedly induces differentiation of hematopoietic stem cells and progenitors in the bone marrow, augments myelopoiesis but not lymphopoiesis, and increases numbers of myeloid cells in blood and spleen. Whereas progenitor differentiation relies on partial inhibition of c-Kit by imatinib, lineage commitment depends upon inhibition of other PTKs. Thus, imatinib mimics “emergency hematopoiesis,” a physiological innate immune response to infection. Increasing neutrophil numbers by adoptive transfer sufficed to reduce mycobacterial load, and imatinib reduced bacterial load of Franciscella spp., which do not utilize imatinib-sensitive PTKs for pathogenesis. Thus, potentiation of the immune response by imatinib at low doses may facilitate clearance of diverse microbial pathogens. PMID:25822986

Low doses of imatinib induce myelopoiesis and enhance host anti-microbial immunity.

PubMed

Napier, Ruth J; Norris, Brian A; Swimm, Alyson; Giver, Cynthia R; Harris, Wayne A C; Laval, Julie; Napier, Brooke A; Patel, Gopi; Crump, Ryan; Peng, Zhenghong; Bornmann, William; Pulendran, Bali; Buller, R Mark; Weiss, David S; Tirouvanziam, Rabindra; Waller, Edmund K; Kalman, Daniel

2015-03-01

Imatinib mesylate (Gleevec) inhibits Abl1, c-Kit, and related protein tyrosine kinases (PTKs) and serves as a therapeutic for chronic myelogenous leukemia and gastrointestinal stromal tumors. Imatinib also has efficacy against various pathogens, including pathogenic mycobacteria, where it decreases bacterial load in mice, albeit at doses below those used for treating cancer. We report that imatinib at such low doses unexpectedly induces differentiation of hematopoietic stem cells and progenitors in the bone marrow, augments myelopoiesis but not lymphopoiesis, and increases numbers of myeloid cells in blood and spleen. Whereas progenitor differentiation relies on partial inhibition of c-Kit by imatinib, lineage commitment depends upon inhibition of other PTKs. Thus, imatinib mimics "emergency hematopoiesis," a physiological innate immune response to infection. Increasing neutrophil numbers by adoptive transfer sufficed to reduce mycobacterial load, and imatinib reduced bacterial load of Franciscella spp., which do not utilize imatinib-sensitive PTKs for pathogenesis. Thus, potentiation of the immune response by imatinib at low doses may facilitate clearance of diverse microbial pathogens.

Do European Standard Disinfectant tests truly simulate in-use microbial and organic soiling conditions on food preparation surfaces?

PubMed

Meyer, B; Morin, V N; Rödger, H-J; Holah, J; Bird, C

2010-04-01

The results from European standard disinfectant tests are used as one basis to approve the use of disinfectants in Europe. The design of these laboratory-based tests should thus simulate as closely as possible the practical conditions and challenges that the disinfectants would encounter in use. No evidence is available that the organic and microbial loading in these tests simulates actual levels in the food service sector. Total organic carbon (TOC) and total viable count (TVC) were determined on 17 visibly clean and 45 visibly dirty surfaces in two restaurants and the food preparation surfaces of a large retail store. These values were compared to reference values recovered from surfaces soiled with the organic and microbial loading, following the standard conditions of the European Surface Test for bactericidal efficacy, EN 13697. The TOC reference values for clean and dirty conditions were higher than the data from practice, but cannot be regarded as statistical outliers. This was considered as a conservative assessment; however, as additional nine TOC samples from visibly dirty surfaces were discarded from the analysis, as their loading made them impossible to process. Similarly, the recovery of test organisms from surfaces contaminated according to EN 13697 was higher than the TVC from visibly dirty surfaces in practice; though they could not be regarded as statistical outliers of the whole data field. No correlation was found between TVC and TOC in the sampled data, which re-emphasizes the potential presence of micro-organisms on visibly clean surfaces and thus the need for the same degree of disinfection as visibly dirty surfaces. The organic soil and the microbial burden used in EN disinfectant standards represent a realistic worst-case scenario for disinfectants used in the food service and food-processing areas.

Disease Resistance in the Drywood Termite, Incisitermes schwarzi: Does Nesting Ecology Affect Immunocompetence?

PubMed Central

Calleri, Daniel V.; Rosengaus, Rebeca B.; Traniello, James F.A.

2010-01-01

Termites live in nests that can differ in microbial load and thus vary in degree of disease risk. It was hypothesized that termite investment in immune response would differ in species living in nest environments that vary in the richness and abundance of microbes. Using the drywood termite, Incisitermes schwarzi Banks (Isoptera: Kalotermitidae), as a model for species having low nest and cuticular microbial loads, the susceptibility of individuals and groups to conidia of the entomopathogenic fungus, Metarhizium anisopliae Sorokin (Hypocreales: Clavicipitaceae), was examined. The survivorship of I. schwarzi was compared to that of the dampwood termite, Zootermopsis angusticollis Hagen (Termopsidae), a species with comparatively high microbial loads. The results indicated that I. schwarzi derives similar benefits from group living as Z. angusticollis: isolated termites had 5.5 times the hazard ratio of death relative to termites nesting in groups of 25 while termites in groups of 10 did not differ significantly from the groups of 25. The results also indicated, after controlling for the influence of group size and conidia exposure on survivorship, that Z. angusticollis was significantly more susceptible to fungal infection than I. schwarzi, the former having 1.6 times the hazard ratio of death relative to drywood termites. Thus, disease susceptibility and individual investment in immunocompetence may not be dependent on interspecific variation in microbial pressures. The data validate prior studies indicating that sociality has benefits in infection control and suggest that social mechanisms of disease resistance, rather than individual physiological and immunological adaptations, may have been the principle target of selection related to variation in infection risk from microbes in the nest environment of different termite species. PMID:20572790

Interplay Between Innate Immunity and the Plant Microbiota.

PubMed

Hacquard, Stéphane; Spaepen, Stijn; Garrido-Oter, Ruben; Schulze-Lefert, Paul

2017-08-04

The innate immune system of plants recognizes microbial pathogens and terminates their growth. However, recent findings suggest that at least one layer of this system is also engaged in cooperative plant-microbe interactions and influences host colonization by beneficial microbial communities. This immune layer involves sensing of microbe-associated molecular patterns (MAMPs) by pattern recognition receptors (PRRs) that initiate quantitative immune responses to control host-microbial load, whereas diversification of MAMPs and PRRs emerges as a mechanism that locally sculpts microbial assemblages in plant populations. This suggests a more complex microbial management role of the innate immune system for controlled accommodation of beneficial microbes and in pathogen elimination. The finding that similar molecular strategies are deployed by symbionts and pathogens to dampen immune responses is consistent with this hypothesis but implies different selective pressures on the immune system due to contrasting outcomes on plant fitness. The reciprocal interplay between microbiota and the immune system likely plays a critical role in shaping beneficial plant-microbiota combinations and maintaining microbial homeostasis.

Membrane biofouling process correlated to the microbial community succession in an A/O MBR.

PubMed

Chen, Chun-Hong; Fu, Yuan; Gao, Da-Wen

2015-12-01

The microbial community succession of the biofouling layer in a submerged anoxic/oxic membrane biological reactor (A/O MBR) that fed with synthesized domestic wastewater was investigated under three different flux conditions without the changing of the nutrient load. The noticeable microbial community succession and its significant correlation with the metabolic products were observed under the subcritical flux condition. Under the supercritical flux condition, the microbial community shift was in a different pattern compared with that under the subcritical flux condition and it was affected by the increased permeable suction more than the metabolic products. The most abundant microorganisms in the foulants were β-proteobacteria and γ-proteobacteria which can reach more than 20% of the microbial community. However the microorganisms which had significant correlation with the metabolic products were in lower abundance. Copyright © 2015 Elsevier Ltd. All rights reserved.

Microbial community structure associated with the high loading anaerobic codigestion of olive mill and abattoir wastewaters.

PubMed

Gannoun, Hana; Omri, Ilhem; Chouari, Rakia; Khelifi, Eltaief; Keskes, Sajiaa; Godon, Jean-Jacques; Hamdi, Moktar; Sghir, Abdelghani; Bouallagui, Hassib

2016-02-01

The effect of increasing the organic loading rates (OLRs) on the performance of the anaerobic codigestion of olive mill (OMW) and abattoir wastewaters (AW) was investigated under mesophilic and thermophilic conditions. The structure of the microbial community was also monitored. Increasing OLR to 9g of chemical oxygen demand (COD) L(-1)d(-1) affected significantly the biogas yield and microbial diversity at 35°C. However, at 55°C digester remained stable until OLR of 12g of CODL(-1)d(-1) with higher COD removal (80%) and biogas yield (0.52Lg(-1) COD removed). Significant differences in the bacterial communities were detected between mesophilic and thermophilic conditions. The dominant phyla detected in the digester at both phases were the Firmicutes, Actinobacteria, Bacteroidetes, Synergistetes and Spirochaete. However, Verrucomicrobia, Proteobacteria and the candidate division BRC1 were only detected at thermophilic conditions. The Methanobacteriales and the Thermoplasmales were found as a high predominant archaeal member in the anaerobic sludge. Copyright © 2015 Elsevier Ltd. All rights reserved.

Bi-layered nanocomposite bandages for controlling microbial infections and overproduction of matrix metalloproteinase activity.

PubMed

Anjana, J; Mohandas, Annapoorna; Seethalakshmy, S; Suresh, Maneesha K; Menon, Riju; Biswas, Raja; Jayakumar, R

2018-04-15

Chronic diabetic wounds is characterised by increased microbial contamination and overproduction of matrix metalloproteases that would degrade the extracellular matrix. A bi-layer bandage was developed, that promotes the inhibition of microbial infections and matrix metalloprotease (MMPs) activity. Bi-layer bandage containing benzalkonium chloride loaded gelatin nanoparticles (BZK GNPs) in chitosan-Hyaluronic acid (HA) as a bottom layer and sodium alendronate containing chitosan as top layer was developed. We hypothesized that the chitosan-gelatin top layer with sodium alendronate could inhibit the MMPs activity, whereas the chitosan-HA bottom layer with BZK GNPs (240±66nm) would enable the elimination of microbes. The porosity, swelling and degradation nature of the prepared Bi-layered bandage was studied. The bottom layer could degrade within 4days whereas the top layer remained upto 7days. The antimicrobial activity of the BZK NPs loaded bandage was determined using normal and clinical strains. Gelatin zymography shows that the proteolytic activity of MMP was inhibited by the bandage. Copyright © 2017 Elsevier B.V. All rights reserved.

Metagenomic analysis of a desulphurisation system used to treat biogas from vinasse methanisation.

PubMed

Dias, Marcela França; Colturato, Luis Felipe; de Oliveira, João Paulo; Leite, Laura Rabelo; Oliveira, Guilherme; Chernicharo, Carlos Augusto; de Araújo, Juliana Calabria

2016-04-01

We investigated the response of microbial community to changes in H2S loading rate in a microaerated desulphurisation system treating biogas from vinasse methanisation. H2S removal efficiency was high, and both COD and DO seemed to be important parameters to biomass activity. DGGE analysis retrieved sequences of sulphide-oxidising bacteria (SOB), such as Thioalkalimicrobium sp. Deep sequencing analysis revealed that the microbial community was complex and remained constant throughout the experiment. Most sequences belonged to Firmicutes and Proteobacteria, and, to a lesser extent, Bacteroidetes, Chloroflexi, and Synergistetes. Despite the high sulphide removal efficiency, the abundance of the taxa of SOB was low, and was negatively affected by the high sulphide loading rate. Copyright © 2016 Elsevier Ltd. All rights reserved.

Influence of aeolian activities on the distribution of microbial abundance in glacier ice

NASA Astrophysics Data System (ADS)

Chen, Y.; Li, X.-K.; Si, J.; Wu, G.-J.; Tian, L.-D.; Xiang, S.-R.

2014-10-01

Microorganisms are continuously blown onto the glacier snow, and thus the glacial depth profiles provide excellent archives of microbial communities and climatic and environmental changes. However, it is uncertain about how aeolian processes that cause climatic changes control the distribution of microorganisms in the glacier ice. In the present study, microbial density, stable isotopic ratios, 18O / 16O in the precipitation, and mineral particle concentrations along the glacial depth profiles were collected from ice cores from the Muztag Ata glacier and the Dunde ice cap. The ice core data showed that microbial abundance was often, but not always associated with high concentrations of particles. Results also revealed clear seasonal patterning with high microbial abundance occurring in both the cooling autumn and warming spring-summer seasons. Microbial comparisons among the neighbouring glaciers display a heterogeneous spatial pattern, with the highest microbial cell density in the glaciers lying adjacent to the central Asian deserts and lowest microbial density in the southwestern margin of the Tibetan Plateau. In conclusion, microbial data of the glaciers indicates the aeolian deposits of microorganisms in the glacier ice and that the spatial patterns of microorgansisms are related to differences in sources of microbial flux and intensity of aeolian activities in the current regions. The results strongly support our hypothesis of aeolian activities being the main agents controlling microbial load in the glacier ice.

Seasonal microbial and environmental parameters at Crocker Reef, Florida Keys, 2014–2015

USGS Publications Warehouse

Kellogg, Christina A.; Yates, Kimberly K.; Lawler, Stephanie N.; Moore, Christopher S.; Smiley, Nathan A.

2015-11-04

Microbial measurements included enumeration of total bacteria, enumeration of virus-like particles, and plate counts of Vibrio spp. colony-forming units (CFU). These measurements were intended to give a sense of any seasonal changes in the total microbial load and to provide an indication of water quality. Additional environmental parameters measured included water temperature, salinity, dissolved oxygen, and pH. Four sites (table 1) were intensively sampled for periods of approximately 48 hours during summer (July 2014) and winter (January–February 2015), during which water samples were collected every 4 hours for analysis, except when prevented by weather conditions.

Analysis of Microbial Communities in Biofilms from CSTR-Type Hollow Fiber Membrane Biofilm Reactors for Autotrophic Nitrification and Hydrogenotrophic Denitrification.

PubMed

Shin, Jung-Hun; Kim, Byung-Chun; Choi, Okkyoung; Kim, Hyunook; Sang, Byoung-In

2015-10-01

Two hollow fiber membrane biofilm reactors (HF-MBfRs) were operated for autotrophic nitrification and hydrogenotrophic denitrification for over 300 days. Oxygen and hydrogen were supplied through the hollow fiber membrane for nitrification and denitrification, respectively. During the period, the nitrogen was removed with the efficiency of 82-97% for ammonium and 87-97% for nitrate and with the nitrogen removal load of 0.09-0.26 kg NH4(+)-N/m(3)/d and 0.10-0.21 kg NO3(-)-N/m(3)/d, depending on hydraulic retention time variation by the two HF-MBfRs for autotrophic nitrification and hydrogenotrophic denitrification, respectively. Biofilms were collected from diverse topological positions in the reactors, each at different nitrogen loading rates, and the microbial communities were analyzed with partial 16S rRNA gene sequences in denaturing gradient gel electrophoresis (DGGE). Detected DGGE band sequences in the reactors were correlated with nitrification or denitrification. The profile of the DGGE bands depended on the NH4(+) or NO3(-) loading rate, but it was hard to find a major strain affecting the nitrogen removal efficiency. Nitrospira-related phylum was detected in all biofilm samples from the nitrification reactors. Paracoccus sp. and Aquaspirillum sp., which are an autohydrogenotrophic bacterium and an oligotrophic denitrifier, respectively, were observed in the denitrification reactors. The distribution of microbial communities was relatively stable at different nitrogen loading rates, and DGGE analysis based on 16S rRNA (341f /534r) could successfully detect nitrate-oxidizing and hydrogen-oxidizing bacteria but not ammonium-oxidizing bacteria in the HF-MBfRs.

Effect of methionine supplementation in chicken feed on the quality and shelf life of fresh poultry meat.

PubMed

Albrecht, Antonia; Herbert, Ulrike; Miskel, Dennis; Heinemann, Celine; Braun, Carina; Dohlen, Sophia; Zeitz, Johanna O; Eder, Klaus; Saremi, Behnam; Kreyenschmidt, Judith

2017-08-01

The aim of this study was to investigate the influence of different methionine sources and concentrations on the quality and spoilage process of broiler meat. The trial was comprised of 7 treatment groups: one basal group (suboptimal in Methionine+Cysteine; i.e., 0.89, 0.74, 0.69% in DM SID Met+Cys in starter, grower, and finisher diets, respectively) and 3 doses (0.10, 0.25, and 0.40%) of either DL-Methionine (DLM) or DL-2-hydroxy-4-methylthio butanoic acid (DL-HMTBA) on an equimolar basis of the DLM-supplemented groups. The broilers were fed the diets for 35 d, then slaughtered and processed. The filets were aerobically packed and stored under temperature controlled conditions at 4°C. Meat quality investigations were comprised of microbial investigations (total viable count and Pseudomonas spp.), pH and drip loss measurements of the filets. The shelf life of the meat samples was determined based on sensory parameters. After slaughtering, all supplemented meat samples showed a high quality, whereby no differences between the 2 methionine sources could be detected for the microbial load, pH, and drip loss. In comparison to the control group, the supplemented samples showed a higher sensory quality, characterized by a fresh smell and fresh red color. Methionine supplementation had a significant influence on meat quality parameters during storage. The microbial load, pH and drip loss of the chicken filets were positively correlated to the methionine concentration. Additionally, the microbial load at the end of storage was positively correlated to pH and drip loss values. Nevertheless, the microbial parameters were in a normal range and the positive correlation to methionine concentration did not affect the sensory shelf life. The mean sensory shelf life of the broiler filets varied between 7 to 9 d. During storage, no difference in the development of sensory parameters was observed between the supplemented groups, while the spoilage process of the basal group occurred slightly faster. In conclusion, methionine concentration, but not methionine source, effected meat quality parameters in breast muscles of broilers. © 2017 Poultry Science Association Inc.

Optimization of enhanced bioelectrical reactor with electricity from microbial fuel cells for groundwater nitrate removal.

PubMed

Liu, Ye; Zhang, Baogang; Tian, Caixing; Feng, Chuanping; Wang, Zhijun; Cheng, Ming; Hu, Weiwu

2016-01-01

Factors influencing the performance of a continual-flow bioelectrical reactor (BER) intensified by microbial fuel cells for groundwater nitrate removal, including nitrate load, carbon source and hydraulic retention time (HRT), were investigated and optimized by response surface methodology (RSM). With the target of maximum nitrate removal and minimum intermediates accumulation, nitrate load (for nitrogen) of 60.70 mg/L, chemical oxygen demand (COD) of 849.55 mg/L and HRT of 3.92 h for the BER were performed. COD was the dominant factor influencing performance of the system. Experimental results indicated the undistorted simulation and reliable optimized values. These demonstrate that RSM is an effective method to evaluate and optimize the nitrate-reducing performance of the present system and can guide mathematical models development to further promote its practical applications.

Characterization of indoor bioaerosols from a hospital ward in a tropical setting.

PubMed

Sudharsanam, S; Swaminathan, S; Ramalingam, A; Thangavel, G; Annamalai, R; Steinberg, R; Balakrishnan, K; Srikanth, P

2012-06-01

Study was conducted to assess whether temporal variation exists in airborne microbial concentrations of a hospital ward (west-Chennai, India) using active and passive methods, and characterise the microorganisms. Air samples (duplicates) were collected simultaneously using exposed-plate, impingement (BioSampler) and filtration (personal sampling filter cassette loaded with gelatin filter) methods over different periods of the year. Bacterial plates were incubated at 37°C and observed for growth after 48h; fungal plates were incubated at 25°C and 37°C and observed upto 7 days. Microorganisms were identified using standard microbiological procedures. Microbial loads were found to vary with the sampling method. Concentrations of bacteria were higher (exposed-plate: 45-150 CFU/plate; impingement: 1.12E+03-1.6856E+05 CFU/m(3); filtration: 3.788E+03-1.91111E+05 CFU/m(3)) than fungi (exposed-plate: 0-13 CFU/plate; impingement: 0-3.547E+03 CFU/m(3); filtration: 0-1.515E+04 CFU/ m(3)). Coagulase-negative Staphylococci and Micrococci were the predominant Gram-positive cocci in active and passive samples. Enterobacter and Pseudomonas were the predominant Gram-negative bacilli. Among fungi, Aspergillus niger was isolated throughout the year. There was no significant temporal variation in airborne microbial loads irrespective of methods. Exposed-plate method was found to capture microorganisms efficiently with little variation in duplicate samples, suggesting its use in hospitals for preliminary assessment of indoor air quality and determine pathogenic microorganisms due to particle fall-out.

Microbial secondary metabolites in homes in association with moisture damage and asthma.

PubMed

Kirjavainen, P V; Täubel, M; Karvonen, A M; Sulyok, M; Tiittanen, P; Krska, R; Hyvärinen, A; Pekkanen, J

2016-06-01

We aimed to characterize the presence of microbial secondary metabolites in homes and their association with moisture damage, mold, and asthma development. Living room floor dust was analyzed by LC-MS/MS for 333 secondary metabolites from 93 homes of 1-year-old children. Moisture damage was present in 15 living rooms. At 6 years, 8 children had active and 15 lifetime doctor-diagnosed asthma. The median number of different metabolites per house was 17 (range 8-29) and median sum load 65 (4-865) ng/m(2) . Overall 42 different metabolites were detected. The number of metabolites present tended to be higher in homes with mold odor or moisture damage. The higher sum loads and number of metabolites with loads over 10 ng/m(2) were associated with lower prevalence of active asthma at 6 years (aOR 0.06 (95% CI <0.001-0.96) and 0.05 (<0.001-0.56), respectively). None of the individual metabolites, which presence tended (P < 0.2) to be increased by moisture damage or mold, were associated with increased risk of asthma. Microbial secondary metabolites are ubiquitously present in home floor dust. Moisture damage and mold tend to increase their numbers and amount. There was no evidence indicating that the secondary metabolites determined would explain the association between moisture damage, mold, and the development of asthma. © 2015 The Authors. Indoor Air published by John Wiley & Sons Ltd.

Gut Microbiota and Salivary Diagnostics: The Mouth Is Salivating to Tell Us Something.

PubMed

Kodukula, Krishna; Faller, Douglas V; Harpp, David N; Kanara, Iphigenia; Pernokas, Julie; Pernokas, Mark; Powers, Whitney R; Soukos, Nikolaos S; Steliou, Kosta; Moos, Walter H

2017-01-01

The microbiome of the human body represents a symbiosis of microbial networks spanning multiple organ systems. Bacteria predominantly represent the diversity of human microbiota, but not to be forgotten are fungi, viruses, and protists. Mounting evidence points to the fact that the "microbial signature" is host-specific and relatively stable over time. As our understanding of the human microbiome and its relationship to the health of the host increases, it is becoming clear that many and perhaps most chronic conditions have a microbial involvement. The oral and gastrointestinal tract microbiome constitutes the bulk of the overall human microbial load, and thus presents unique opportunities for advancing human health prognosis, diagnosis, and therapy development. This review is an attempt to catalog a broad diversity of recent evidence and focus it toward opportunities for prevention and treatment of debilitating illnesses.

Efficient removal of nitrobenzene and concomitant electricity production by single-chamber microbial fuel cells with activated carbon air-cathode.

PubMed

Zhang, Enren; Wang, Feng; Zhai, Wenjing; Scott, Keith; Wang, Xu; Diao, Guowang

2017-04-01

Single-chamber microbial fuel cells (S-MFCs) with bio-anodes and activated carbon (AC) air-cathodes showed high nitrobenzene (NB) tolerance and NB removal with concomitant electricity production. The maximum power over 25Wm -3 could be obtained when S-MFCs were operated in the NB loading range of 1.2-6.2molm -3 d -1 , and stable electricity production over 13.7Wm -3 could be produced in a NB loading range of 1.2-14.7molm -3 d -1 . The present S-MFCs exhibited high NB removal performance with NB removal efficiency over 97% even when the NB loading rate was increased to 17.2molm -3 d -1 . The potential NB reduced product (i.e. aniline) could also be effectively removed from influents. The findings in this study means that single-chamber MFCs assembled with pre-enriched bio-anodes and AC air-cathodes could be developed as effective bio-electrochemical systems to remove NB from wastewaters and to harvest energy instead of consuming energy. Copyright © 2017 Elsevier Ltd. All rights reserved.

Microbial resistance related to antibiotic-loaded bone cement: a historical review.

PubMed

Walker, Lucy C; Baker, Paul; Holleyman, Richard; Deehan, David

2017-12-01

The use of antibiotic-loaded bone cement (ALBC) has a range of indications for use in orthopaedics. It has the advantage of delivering high loads of antibiotics to a targeted site, thereby avoiding the side effects associated with systemic administration. However, there is concern that the use of ALBC may precipitate the development of antibiotic-resistant bacteria. This review focuses on (1) the published research using both animal and human models examining the association between ALBC and the induction of microbial resistance (2) the mechanisms by which antimicrobial resistance develop (3) the research pertaining to specific classes of antibiotics commonly used in orthopaedic practice (4) the recent developments in calcium sulphate beads, nanoparticles and chitosan, as alternative antimicrobial treatments for periprosthetic joint infections. The literature for and against a link between ALBC and the development of microbiological resistance is reviewed and presented. It is concluded that further research is needed to develop a defined set of indications for the use of ALBC in the management of periprosthetic joint infection. In addition, further research into alternative antimicrobial therapies in this area should be encouraged.

Effects of temperature and organic loading rate on the performance and microbial community of anaerobic co-digestion of waste activated sludge and food waste.

PubMed

Gou, Chengliu; Yang, Zhaohui; Huang, Jing; Wang, Huiling; Xu, Haiyin; Wang, Like

2014-06-01

Anaerobic co-digestion of waste activated sludge and food waste was investigated semi-continuously using continuously stirred tank reactors. Results showed that the performance of co-digestion system was distinctly influenced by temperature and organic loading rate (OLR) in terms of gas production rate (GPR), methane yield, volatile solids (VS) removal efficiency and the system stability. The highest GPR at 55 °C was 1.6 and 1.3 times higher than that at 35 and 45 °C with the OLR of 1 g VSL(-1)d(-1), and the corresponding average CH₄ yields were 0.40, 0.26 and 0.30 L CH₄ g(-1)VSadded, respectively. The thermophilic system exhibited the best load bearing capacity at extremely high OLR of 7 g VSL(-1)d(-1), while the mesophilic system showed the best process stability at low OLRs (< 5 g VSL(-1)d(-1)). Temperature had a more remarkable effect on the richness and diversity of microbial populations than the OLR. Copyright © 2014 Elsevier Ltd. All rights reserved.

Low Stress Mechanical Properties of Plasma-Treated Cotton Fabric Subjected to Zinc Oxide-Anti-Microbial Treatment.

PubMed

Kan, Chi-Wai; Lam, Yin-Ling

2013-01-22

Cotton fabrics are highly popular because of their excellent properties such as regeneration, bio-degradation, softness, affinity to skin and hygroscopic properties. When in contact with the human body, cotton fabrics offer an ideal environment for microbial growth due to their ability to retain oxygen, moisture and warmth, as well as nutrients from spillages and body sweat. Therefore, an anti-microbial coating formulation (Microfresh and Microban together with zinc oxide as catalyst) was developed for cotton fabrics to improve treatment effectiveness. In addition, plasma technology was employed in the study which roughened the surface of the materials, improving the loading of zinc oxides on the surface. In this study, the low stress mechanical properties of plasma pre-treated and/or anti-microbial-treated cotton fabric were studied. The overall results show that the specimens had improved bending properties when zinc oxides were added in the anti-microbial coating recipe. Also, without plasma pre-treatment, anti-microbial-treatment of cotton fabric had a positive effect only on tensile resilience, shear stress at 0.5° and compressional energy, while plasma-treated specimens had better overall tensile properties even after anti-microbial treatment.

Low Stress Mechanical Properties of Plasma-Treated Cotton Fabric Subjected to Zinc Oxide-Anti-Microbial Treatment

PubMed Central

Kan, Chi-Wai; Lam, Yin-Ling

2013-01-01

Cotton fabrics are highly popular because of their excellent properties such as regeneration, bio-degradation, softness, affinity to skin and hygroscopic properties. When in contact with the human body, cotton fabrics offer an ideal environment for microbial growth due to their ability to retain oxygen, moisture and warmth, as well as nutrients from spillages and body sweat. Therefore, an anti-microbial coating formulation (Microfresh and Microban together with zinc oxide as catalyst) was developed for cotton fabrics to improve treatment effectiveness. In addition, plasma technology was employed in the study which roughened the surface of the materials, improving the loading of zinc oxides on the surface. In this study, the low stress mechanical properties of plasma pre-treated and/or anti-microbial-treated cotton fabric were studied. The overall results show that the specimens had improved bending properties when zinc oxides were added in the anti-microbial coating recipe. Also, without plasma pre-treatment, anti-microbial-treatment of cotton fabric had a positive effect only on tensile resilience, shear stress at 0.5° and compressional energy, while plasma-treated specimens had better overall tensile properties even after anti-microbial treatment. PMID:28809311

Assessing Coral Reefs on a Pacific-Wide Scale Using the Microbialization Score

PubMed Central

McDole, Tracey; Nulton, James; Barott, Katie L.; Felts, Ben; Hand, Carol; Hatay, Mark; Lee, Hochul; Nadon, Marc O.; Nosrat, Bahador; Salamon, Peter; Bailey, Barbara; Sandin, Stuart A.; Vargas-Angel, Bernardo; Youle, Merry; Zgliczynski, Brian J.; Brainard, Russell E.; Rohwer, Forest

2012-01-01

The majority of the world's coral reefs are in various stages of decline. While a suite of disturbances (overfishing, eutrophication, and global climate change) have been identified, the mechanism(s) of reef system decline remain elusive. Increased microbial and viral loading with higher percentages of opportunistic and specific microbial pathogens have been identified as potentially unifying features of coral reefs in decline. Due to their relative size and high per cell activity, a small change in microbial biomass may signal a large reallocation of available energy in an ecosystem; that is the microbialization of the coral reef. Our hypothesis was that human activities alter the energy budget of the reef system, specifically by altering the allocation of metabolic energy between microbes and macrobes. To determine if this is occurring on a regional scale, we calculated the basal metabolic rates for the fish and microbial communities at 99 sites on twenty-nine coral islands throughout the Pacific Ocean using previously established scaling relationships. From these metabolic rate predictions, we derived a new metric for assessing and comparing reef health called the microbialization score. The microbialization score represents the percentage of the combined fish and microbial predicted metabolic rate that is microbial. Our results demonstrate a strong positive correlation between reef microbialization scores and human impact. In contrast, microbialization scores did not significantly correlate with ocean net primary production, local chla concentrations, or the combined metabolic rate of the fish and microbial communities. These findings support the hypothesis that human activities are shifting energy to the microbes, at the expense of the macrobes. Regardless of oceanographic context, the microbialization score is a powerful metric for assessing the level of human impact a reef system is experiencing. PMID:22970122

Assessing coral reefs on a Pacific-wide scale using the microbialization score.

PubMed

McDole, Tracey; Nulton, James; Barott, Katie L; Felts, Ben; Hand, Carol; Hatay, Mark; Lee, Hochul; Nadon, Marc O; Nosrat, Bahador; Salamon, Peter; Bailey, Barbara; Sandin, Stuart A; Vargas-Angel, Bernardo; Youle, Merry; Zgliczynski, Brian J; Brainard, Russell E; Rohwer, Forest

2012-01-01

The majority of the world's coral reefs are in various stages of decline. While a suite of disturbances (overfishing, eutrophication, and global climate change) have been identified, the mechanism(s) of reef system decline remain elusive. Increased microbial and viral loading with higher percentages of opportunistic and specific microbial pathogens have been identified as potentially unifying features of coral reefs in decline. Due to their relative size and high per cell activity, a small change in microbial biomass may signal a large reallocation of available energy in an ecosystem; that is the microbialization of the coral reef. Our hypothesis was that human activities alter the energy budget of the reef system, specifically by altering the allocation of metabolic energy between microbes and macrobes. To determine if this is occurring on a regional scale, we calculated the basal metabolic rates for the fish and microbial communities at 99 sites on twenty-nine coral islands throughout the Pacific Ocean using previously established scaling relationships. From these metabolic rate predictions, we derived a new metric for assessing and comparing reef health called the microbialization score. The microbialization score represents the percentage of the combined fish and microbial predicted metabolic rate that is microbial. Our results demonstrate a strong positive correlation between reef microbialization scores and human impact. In contrast, microbialization scores did not significantly correlate with ocean net primary production, local chla concentrations, or the combined metabolic rate of the fish and microbial communities. These findings support the hypothesis that human activities are shifting energy to the microbes, at the expense of the macrobes. Regardless of oceanographic context, the microbialization score is a powerful metric for assessing the level of human impact a reef system is experiencing.

Mechanisms of post-supply contamination of drinking water in Bagamoyo, Tanzania.

PubMed

Harris, Angela R; Davis, Jennifer; Boehm, Alexandria B

2013-09-01

Access to household water connections remains low in sub-Saharan Africa, representing a public health concern. Previous studies have shown water stored in the home to be more contaminated than water at the source; however, the mechanisms of post-supply contamination remain unclear. Using water quality measurements and structured observations of households in Bagamoyo, Tanzania, this study elucidates the causal mechanisms of the microbial contamination of drinking water after collection from a communal water source. The study identifies statistically significant loadings of fecal indicator bacteria (FIB) occurring immediately after filling the storage container at the source and after extraction of the water from the container in the home. Statistically significant loadings of FIB also occur with various water extraction methods, including decanting from the container and use of a cup or ladle. Additionally, pathogenic genes of Escherichia coli were detected in stored drinking water but not in the source from which it was collected, highlighting the potential health risks of post-supply contamination. The results of the study confirm that storage containers and extraction utensils introduce microbial contamination into stored drinking water, and suggest that further research is needed to identify methods of water extraction that prevent microbial contamination of drinking water.

Bioluminescence ATP Monitoring for the Routine Assessment of Food Contact Surface Cleanliness in a University Canteen

PubMed Central

Osimani, Andrea; Garofalo, Cristiana; Clementi, Francesca; Tavoletti, Stefano; Aquilanti, Lucia

2014-01-01

ATP bioluminescence monitoring and traditional microbiological analyses (viable counting of total mesophilic aerobes, coliforms and Escherichia coli) were used to evaluate the effectiveness of Sanitation Standard Operating Procedures (SSOP) at a university canteen which uses a HACCP-based approach. To that end, 10 cleaning control points (CPs), including food contact surfaces at risk of contamination from product residues or microbial growth, were analysed during an 8-month monitoring period. Arbitrary acceptability limits were set for both microbial loads and ATP bioluminescence readings. A highly significant correlation (r = 0.99) between the means of ATP bioluminescence readings and the viable counts of total mesophilic aerobes was seen, thus revealing a strong association of these parameters with the level of surface contamination. Among CPs, the raw meat and multi-purpose chopping boards showed the highest criticalities. Although ATP bioluminescence technology cannot substitute traditional microbiological analyses for the determination of microbial load on food contact surfaces, it has proved to be a powerful tool for the real time monitoring of surface cleanliness at mass catering plants, for verify the correct application of SSOP, and hence for their implementation/revision in the case of poor hygiene. PMID:25329534

Effect of long term chilled (up to 5weeks) then frozen (up to 12months) storage at two different sub-zero holding temperatures on beef: 1. Meat quality and microbial loads.

PubMed

Holman, Benjamin W B; Coombs, Cassius E O; Morris, Stephen; Kerr, Matthew J; Hopkins, David L

2017-11-01

Beef loins (LL) stored under different chilled-then-frozen storage combinations (up to 5 and 52weeks, respectively) and two frozen holding temperatures were evaluated for microbial load and meat quality parameters. We found holding temperature effects to be negligible, which suggest -12°C could deliver comparable quality LL to -18°C across these same storage periods. Meat quality parameters varied significantly, but when compared to existing consumer thresholds these may not be perceptible, colour being the exception which proved unacceptable, earlier into retail display when either chilled and subsequent frozen storage periods were increased. There was insufficient detection of key spoilage microbes to allow for statistical analysis, potentially due to the hygienic and commercially representative LL source, although variation in water activity, glycogen content, pH and other moisture parameters conducive to microbial proliferation were influenced by chilled-then-frozen storage. These outcomes could be applied to defining storage thresholds that assure beef quality within export networks, leveraging market access, and improving product management. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

Use of 16S rRNA sequencing and quantitative PCR to correlate venous leg ulcer bacterial bioburden dynamics with wound expansion, antibiotic therapy, and healing

PubMed Central

Sprockett, Daniel D.; Ammons, Christine G.; Tuttle, Marie S.

2016-01-01

Clinical diagnosis of infection in chronic wounds is currently limited to subjective clinical signs and culture-based methods that underestimate the complexity of wound microbial bioburden as revealed by DNA-based microbial identification methods. Here, we use 16S rRNA next generation sequencing and quantitative polymerase chain reaction to characterize weekly changes in bacterial load, community structure, and diversity associated with a chronic venous leg ulcer over the 15-week course of treatment and healing. Our DNA-based methods and detailed sampling scheme reveal that the bacterial bioburden of the wound is unexpectedly dynamic, including changes in the bacterial load and community structure that correlate with wound expansion, antibiotic therapy, and healing. We demonstrate that these multidimensional changes in bacterial bioburden can be summarized using swabs taken prior to debridement, and therefore, can be more easily collected serially than debridement or biopsy samples. Overall, this case illustrates the importance of detailed clinical indicators and longitudinal sampling to determine the pathogenic significance of chronic wound microbial dynamics and guide best use of antimicrobials for improvement of healing outcomes. PMID:25902876

Influence of the operational parameters on bioelectricity generation in continuous microbial fuel cell, experimental and computational fluid dynamics modelling

NASA Astrophysics Data System (ADS)

Sobieszuk, Paweł; Zamojska-Jaroszewicz, Anna; Makowski, Łukasz

2017-12-01

The influence of the organic loading rate (also known as active anodic chamber volume) on bioelectricity generation in a continuous, two-chamber microbial fuel cell for the treatment of synthetic wastewater, with glucose as the only carbon source, was examined. Ten sets of experiments with different combinations of hydraulic retention times (0.24-1.14 d) and influent chemical oxygen demand concentrations were performed to verify the impact of organic loading rate on the voltage generation capacity of a simple dual-chamber microbial fuel cell working in continuous mode. We found that there is an optimal hydraulic retention time value at which the maximum voltage is generated: 0.41 d. However, there were no similar effects, in terms of voltage generation, when a constant hydraulic retention time with different influent chemical oxygen demand of wastewater was used. The obtained maximal voltage value (600 mV) has also been compared to literature data. Computational fluid dynamics (CFD) was used to calculate the fluid flow and the exit age distribution of fluid elements in the reactor to explain the obtained experimental results and identify the crucial parameters for the design of bioreactors on an industrial scale.

Bioluminescence ATP monitoring for the routine assessment of food contact surface cleanliness in a university canteen.

PubMed

Osimani, Andrea; Garofalo, Cristiana; Clementi, Francesca; Tavoletti, Stefano; Aquilanti, Lucia

2014-10-17

ATP bioluminescence monitoring and traditional microbiological analyses (viable counting of total mesophilic aerobes, coliforms and Escherichia coli) were used to evaluate the effectiveness of Sanitation Standard Operating Procedures (SSOP) at a university canteen which uses a HACCP-based approach. To that end, 10 cleaning control points (CPs), including food contact surfaces at risk of contamination from product residues or microbial growth, were analysed during an 8-month monitoring period. Arbitrary acceptability limits were set for both microbial loads and ATP bioluminescence readings. A highly significant correlation (r = 0.99) between the means of ATP bioluminescence readings and the viable counts of total mesophilic aerobes was seen, thus revealing a strong association of these parameters with the level of surface contamination. Among CPs, the raw meat and multi-purpose chopping boards showed the highest criticalities. Although ATP bioluminescence technology cannot substitute traditional microbiological analyses for the determination of microbial load on food contact surfaces, it has proved to be a powerful tool for the real time monitoring of surface cleanliness at mass catering plants, for verify the correct application of SSOP, and hence for their implementation/revision in the case of poor hygiene.

Characterization of Exoelectrogenic Bacteria Enterobacter Strains Isolated from a Microbial Fuel Cell Exposed to Copper Shock Load

PubMed Central

Feng, Cuijie; Li, Jiangwei; Qin, Dan; Chen, Lixiang; Zhao, Feng; Chen, Shaohua; Hu, Hongbo; Yu, Chang-Ping

2014-01-01

Microorganisms capable of generating electricity in microbial fuel cells (MFCs) have gained increasing interest. Here fourteen exoelectrogenic bacterial strains were isolated from the anodic biofilm in an MFC before and after copper (Cu) shock load by Hungate roll-tube technique with solid ferric (III) oxide as an electron acceptor and acetate as an electron donor. Phylogenetic analysis of the 16S rRNA gene sequences revealed that they were all closely related to Enterobacter ludwigii DSM 16688T within the Enterobacteriaceae family, although these isolated bacteria showed slightly different morphology before and after Cu shock load. Two representative strains R2B1 (before Cu shock load) and B4B2 (after Cu shock load) were chosen for further analysis. B4B2 is resistant to 200 mg L−1 of Cu(II) while R2B1 is not, which indicated the potential selection of the Cu shock load. Raman analysis revealed that both R2B1 and B4B2 contained c-type cytochromes. Cyclic voltammetry measurements revealed that strain R2B1 had the capacity to transfer electrons to electrodes. The experimental results demonstrated that strain R2B1 was capable of utilizing a wide range of substrates, including Luria-Bertani (LB) broth, cellulose, acetate, citrate, glucose, sucrose, glycerol and lactose to generate electricity, with the highest current density of 440 mA·m−2 generated from LB-fed MFC. Further experiments indicated that the bacterial cell density had potential correlation with the current density. PMID:25412475

Optimization of hot water treatment for removing microbial colonies on fresh blueberry surface.

PubMed

Kim, Tae Jo; Corbitt, Melody P; Silva, Juan L; Wang, Dja Shin; Jung, Yean-Sung; Spencer, Barbara

2011-08-01

Blueberries for the frozen market are washed but this process sometimes is not effective or further contaminates the berries. This study was designed to optimize conditions for hot water treatment (temperature, time, and antimicrobial concentration) to remove biofilm and decrease microbial load on blueberries. Scanning electron microscopy (SEM) image showed a well-developed microbial biofilm on blueberries dipped in room temperature water. The biofilm consisted of yeast and bacterial cells attached to the berry surface in the form of microcolonies, which produced exopolymer substances between or upon the cells. Berry exposure to 75 and 90 °C showed little to no microorganisms on the blueberry surface; however, the sensory quality (wax/bloom) of berries at those temperatures was unacceptable. Response surface plots showed that increasing temperature was a significant factor on reduction of aerobic plate counts (APCs) and yeast/mold counts (YMCs) while adding Boxyl® did not have significant effect on APC. Overlaid contour plots showed that treatments of 65 to 70 °C for 10 to 15 s showed maximum reductions of 1.5 and 2.0 log CFU/g on APCs and YMCs, respectively; with acceptable level of bloom/wax score on fresh blueberries. This study showed that SEM, response surface, and overlaid contour plots proved successful in arriving at optima to reduce microbial counts while maintaining bloom/wax on the surface of the blueberries. Since chemical sanitizing treatments such as chlorine showed ineffectiveness to reduce microorganisms loaded on berry surface (Beuchat and others 2001, Sapers 2001), hot water treatment on fresh blueberries could maximize microbial reduction with acceptable quality of fresh blueberries. © 2011 Institute of Food Technologists®

Three-dimensional graphene nanosheets as cathode catalysts in standard and supercapacitive microbial fuel cell

NASA Astrophysics Data System (ADS)

Santoro, Carlo; Kodali, Mounika; Kabir, Sadia; Soavi, Francesca; Serov, Alexey; Atanassov, Plamen

2017-07-01

Three-dimensional graphene nanosheets (3D-GNS) were used as cathode catalysts for microbial fuel cells (MFCs) operating in neutral conditions. 3D-GNS catalysts showed high performance towards oxygen electroreduction in neutral media with high current densities and low hydrogen peroxide generation compared to activated carbon (AC). 3D-GNS was incorporated into air-breathing cathodes based on AC with three different loadings (2, 6 and 10 mgcm-2). Performances in MFCs showed that 3D-GNS had the highest performances with power densities of 2.059 ± 0.003 Wm-2, 1.855 ± 0.007 Wm-2 and 1.503 ± 0.005 Wm-2 for loading of 10, 6 and 2 mgcm-2 respectively. Plain AC had the lowest performances (1.017 ± 0.009 Wm-2). The different cathodes were also investigated in supercapacitive MFCs (SC-MFCs). The addition of 3D-GNS decreased the ohmic losses by 14-25%. The decrease in ohmic losses allowed the SC-MFC with 3D-GNS (loading 10 mgcm-2) to have the maximum power (Pmax) of 5.746 ± 0.186 Wm-2. At 5 mA, the SC-MFC featured an "apparent" capacitive response that increased from 0.027 ± 0.007 F with AC to 0.213 ± 0.026 F with 3D-GNS (loading 2 mgcm-2) and further to 1.817 ± 0.040 F with 3D-GNS (loading 10 mgcm-2).

Allee effect: the story behind the stabilization or extinction of microbial ecosystem.

PubMed

Goswami, Madhurankhi; Bhattacharyya, Purnita; Tribedi, Prosun

2017-03-01

A population exhibiting Allee effect shows a positive correlation between population fitness and population size or density. Allee effect decides the extinction or conservation of a microbial population and thus appears to be an important criterion in population ecology. The underlying factor of Allee effect that decides the stabilization and extinction of a particular population density is the threshold or the critical density of their abundance. According to Allee, microbial populations exhibit a definite, critical or threshold density, beyond which the population fitness of a particular population increases with the rise in population density and below it, the population fitness goes down with the decrease in population density. In particular, microbial population displays advantageous traits such as biofilm formation, expression of virulence genes, spore formation and many more only at a high population density. It has also been observed that microorganisms exhibiting a lower population density undergo complete extinction from the residual microbial ecosystem. In reference to Allee effect, decrease in population density or size introduces deleterious mutations among the population density through genetic drift. Mutations are carried forward to successive generations resulting in its accumulation among the population density thus reducing its microbial fitness and thereby increasing the risk of extinction of a particular microbial population. However, when the microbial load is high, the chance of genetic drift is less, and through the process of biofilm formation, the cooperation existing among the microbial population increases that increases the microbial fitness. Thus, the high microbial population through the formation of microbial biofilm stabilizes the ecosystem by increasing fitness. Taken together, microbial fitness shows positive correlation with the ecosystem conservation and negative correlation with ecosystem extinction.

Microbial monitoring by molecular tools of an upflow anaerobic filter treating abattoir wastewaters.

PubMed

Gannoun, Hana; Khelifi, Eltaief; Omri, Ilhem; Jabari, Linda; Fardeau, Marie-Laure; Bouallagui, Hassib; Godon, Jean-Jacques; Hamdi, Moktar

2013-08-01

The performance of anaerobic digestion of abattoir wastewaters (AW) in an upflow anaerobic filter (UAF) was investigated under mesophilic (37°C) and thermophilic (55°C) conditions. The effects of increasing temperature on the performance of the UAF and on the dynamics of the microbial community of the anaerobic sludge were studied. The results showed that chemical oxygen demand (COD) removal efficiency of 90% was achieved for organic loading rates (OLRs) up to 4.5g CODL(-1)d(-1) in mesophilic conditions, while in thermophilic conditions, the highest OLRs of 9 g CODL(-1)d(-1) led to the efficiency of 72%. The use of molecular and microbiological methods to recover microbial populations involved in this process showed that fermentative bacteria were the prominent members of the sludge microbial community. Three novel strains were identified as Macellibacteroides fermentans, Desulfotomaculum peckii and Defluviitalea saccharophila. Copyright © 2013 Elsevier Ltd. All rights reserved.

Monitoring of oil hydrocarbons pollution in the Sea of Japan, based on detection of marker genes in microbial communities

NASA Astrophysics Data System (ADS)

Kim, A. V.; Buzoleva, L. S.; Bogatyrenko, E. A.; Zemskaya, T. I.; Mamaeva, E. V.

2018-01-01

By means of molecular biology techniques, metabolic potential of microbial communities within the regions of inshore water areas in the Sea of Japan with various anthropogenic load was explored. Presence of functional genes, responsible for oil hydrocarbons destruction, for microbial communities within the regions of inshore water areas in the Sea of Japan was first researched. In total microbial DNA from water mass in the regions with chronic anthropogenic pollution, the genes, responsible for oxidation of broad range of n-alkanes and polycyclic aromatic hydrocarbons, were found. Detection of marker genes in the background water area (in the Vostok Bay) was ever indicating ecological deterioration within this territory. Thereby, it was demonstrated, that molecular genetic methods, aimed at marker gene detection in total bacterial DNA from environment objects, proved themselves to be more effective technique for identification of oil hydrocarbons water pollution, in comparison with trivial culturable methods.

Electricity generation from food wastes and microbial community structure in microbial fuel cells.

PubMed

Jia, Jianna; Tang, Yu; Liu, Bingfeng; Wu, Di; Ren, Nanqi; Xing, Defeng

2013-09-01

Microbial fuel cell (MFC) was studied as an alternate and a novel way to dispose food wastes (FWs) in a waste-to-energy form. Different organic loading rate obviously affected the performance of MFCs fed with FWs. The maximum power density of ~18 W/m(3) (~556 mW/m(2)) was obtained at COD of 3200±400 mg/L and the maximum coulombic efficiency (CE) was ~27.0% at COD of 4900±350 mg/L. The maximum removals of COD, total carbohydrate (TC) and total nitrogen (TN) were ~86.4%, ~95.9% and ~16.1%, respectively. Microbial community analysis using 454 pyrosequencing of 16S rRNA gene demonstrated the combination of the dominant genera of the exoelectrogenic Geobacter and fermentative Bacteroides effectively drove highly efficient and reliable MFC systems with functions of organic matters degradation and electricity generation. Copyright © 2013 Elsevier Ltd. All rights reserved.

Hydrogen production from switchgrass via a hybrid pyrolysis-microbial electrolysis process

DOE PAGES

Lewis, Alex J.; Ren, Shoujie; Ye, Philip; ...

2015-06-30

A new approach to hydrogen production using a hybrid pyrolysis-microbial electrolysis process is described. The aqueous stream generated during pyrolysis of switchgrass was used as a substrate for hydrogen production in a microbial electrolysis cell, achieving a maximum hydrogen production rate of 4.3 L H2/L-day at a loading of 10 g COD/L-anode-day. Hydrogen yields ranged from 50 3.2% to76 0.5% while anode coulombic efficiency ranged from 54 6.5% to 96 0.21%, respectively. Significant conversion of furfural, organic acids and phenolic molecules was observed under both batch and continuous conditions. The electrical and overall energy efficiency ranged from 149-175% and 48-63%,more » respectively. The results demonstrate the potential of the pyrolysis-microbial electrolysis process as a sustainable and efficient route for production of renewable hydrogen with significant implications for hydrocarbon production from biomass.« less

Gut Microbiota and Salivary Diagnostics: The Mouth Is Salivating to Tell Us Something

PubMed Central

Kodukula, Krishna; Faller, Douglas V.; Harpp, David N.; Kanara, Iphigenia; Pernokas, Julie; Pernokas, Mark; Powers, Whitney R.; Soukos, Nikolaos S.; Steliou, Kosta; Moos, Walter H.

2017-01-01

Abstract The microbiome of the human body represents a symbiosis of microbial networks spanning multiple organ systems. Bacteria predominantly represent the diversity of human microbiota, but not to be forgotten are fungi, viruses, and protists. Mounting evidence points to the fact that the “microbial signature” is host-specific and relatively stable over time. As our understanding of the human microbiome and its relationship to the health of the host increases, it is becoming clear that many and perhaps most chronic conditions have a microbial involvement. The oral and gastrointestinal tract microbiome constitutes the bulk of the overall human microbial load, and thus presents unique opportunities for advancing human health prognosis, diagnosis, and therapy development. This review is an attempt to catalog a broad diversity of recent evidence and focus it toward opportunities for prevention and treatment of debilitating illnesses. PMID:29098118

Effects of ionizing radiation on sensorial, chemical, and microbiological quality of frozen corn and peas.

PubMed

Fan, Xuetong; Sokorai, Kimberly J B

2007-08-01

The effects of irradiation (0, 1.8, and 4.5 kGy) on the quality of frozen corn and peas were investigated during a 12month period of postirradiation storage at -18 degrees C. Irradiation of frozen corn and peas caused a reduction in ascorbic acid content of both vegetables and a loss of texture in peas but had no significant effects on instrumental color parameters (L*, a*, and b*), carotenoid and chlorophyll content, or antioxidant capacity of corn and peas. Irradiation reduced microbial loads of frozen peas and increased display life at 23 degrees C of thawed peas by preserving the green color, apparently because of slower increases in the population of acid-producing microorganisms in the irradiated samples. Overall, irradiation significantly reduced the microbial load and increased the display life of peas and had minimal detrimental effects on the quality of frozen corn and peas.

Kinetics of carbendazim degradation in a horizontal tubular biofilm reactor.

PubMed

Alvarado-Gutiérrez, María Luisa; Ruiz-Ordaz, Nora; Galíndez-Mayer, Juvencio; Santoyo-Tepole, Fortunata; Curiel-Quesada, Everardo; García-Mena, Jaime; Ahuatzi-Chacón, Deifilia

2017-04-01

The fungicide carbendazim is an ecotoxic agent affecting aquatic biota. Due to its suspected hormone-disrupting effects, it is considered a "priority hazard substance" by the Water Framework Directive of the European Commission, and its degradation is of major concern. In this work, a horizontal tubular biofilm reactor (HTBR) operating in plug-flow regime was used to study the kinetics of carbendazim removal by an acclimated microbial consortium. The reactor was operated in steady state continuous culture at eight different carbendazim loading rates. The concentrations of the fungicide were determined at several distances of the HTBR. At the loading rates tested, the highest instantaneous removal rates were observed in the first section of the tubular biofilm reactor. No evidence of inhibition of the catabolic activity of the microbial community was found. Strains of the genera Flectobacillus, Klebsiella, Stenotrophomonas, and Flavobacterium were identified in the biofilm; the last three degrade carbendazim in axenic culture.

Multi-year microbial source tracking study characterizing fecal contamination in an urban watershed

USGS Publications Warehouse

Bushon, Rebecca N.; Brady, Amie M. G.; Christensen, Eric D.; Stelzer, Erin A.

2017-01-01

Microbiological and hydrological data were used to rank tributary stream contributions of bacteria to the Little Blue River in Independence, Missouri. Concentrations, loadings and yields of E. coli and microbial source tracking (MST) markers, were characterized during base flow and storm events in five subbasins within Independence, as well as sources entering and leaving the city through the river. The E. coli water quality threshold was exceeded in 29% of base-flow and 89% of storm-event samples. The total contribution of E. coli and MST markers from tributaries within Independence to the Little Blue River, regardless of streamflow, did not significantly increase the median concentrations leaving the city. Daily loads and yields of E. coli and MST markers were used to rank the subbasins according to their contribution of each constituent to the river. The ranking methodology used in this study may prove useful in prioritizing remediation in the different subbasins.

Stormwater runoff drives viral community composition changes in inland freshwaters.

PubMed

Williamson, Kurt E; Harris, Jamie V; Green, Jasmin C; Rahman, Faraz; Chambers, Randolph M

2014-01-01

Storm events impact freshwater microbial communities by transporting terrestrial viruses and other microbes to freshwater systems, and by potentially resuspending microbes from bottom sediments. The magnitude of these impacts on freshwater ecosystems is unknown and largely unexplored. Field studies carried out at two discrete sites in coastal Virginia (USA) were used to characterize the viral load carried by runoff and to test the hypothesis that terrestrial viruses introduced through stormwater runoff change the composition of freshwater microbial communities. Field data gathered from an agricultural watershed indicated that primary runoff can contain viral densities approximating those of receiving waters. Furthermore, viruses attached to suspended colloids made up a large fraction of the total load, particularly in early stages of the storm. At a second field site (stormwater retention pond), RAPD-PCR profiling showed that the viral community of the pond changed dramatically over the course of two intense storms while relatively little change was observed over similar time scales in the absence of disturbance. Comparisons of planktonic and particle-associated viral communities revealed two completely distinct communities, suggesting that particle-associated viruses represent a potentially large and overlooked portion of aquatic viral abundance and diversity. Our findings show that stormwater runoff can quickly change the composition of freshwater microbial communities. Based on these findings, increased storms in the coastal mid-Atlantic region predicted by most climate change models will likely have important impacts on the structure and function of local freshwater microbial communities.

Breast milk cytokine and IgA composition differ in Estonian and Swedish mothers-relationship to microbial pressure and infant allergy.

PubMed

Tomicić, Sara; Johansson, Git; Voor, Tiia; Björkstén, Bengt; Böttcher, Malin Fagerås; Jenmalm, Maria C

2010-10-01

The immune system of the neonate is influenced by maternal immunity during pregnancy and lactation. An altered microbial exposure, possibly underlying the increase of allergic diseases in affluent societies, may affect maternal breast milk immune composition. Secretory IgA (SIgA), IL-4, IL-10, IL-13, IFN-[gamma], TGF-[beta]1, and TGF-[beta]2 were analyzed with ELISA in colostrum and 1-mo mature milk from mothers from Estonia (n = 39) and Sweden (n = 60), the two geographically adjacent countries with different living conditions and allergy incidence. The IL-10 and IFN-[gamma] levels were higher in colostrum from Estonian than Swedish mothers, whereas the opposite was true for TGF-[beta]2. In mature milk, higher SIgA and IFN-[gamma] levels but lower TGF-[beta]1 and TGF-[beta]2 levels were observed in Estonian than Swedish mothers. Interestingly, in Sweden but not Estonia, the TGF-[beta]1 and TGF-[beta]2 levels correlated inversely with environmental endotoxin concentrations, whereas positive correlations to microbial load were observed for IL-4, IL-10, and IFN-[gamma]. High colostral IL-13 levels were associated with allergic sensitization during infancy in Sweden. In conclusion, Estonian mothers have lower breast milk levels of TGF-[beta], particularly TGF-[beta]2, but higher levels of SIgA, IL-10, and IFN-[gamma] than Swedish mothers, possibly because of differences in microbial load.

Effects of organic loading rate on hydrogen and volatile fatty acid production and microbial community during acidogenic hydrogenesis in a continuous stirred tank reactor using molasses wastewater.

PubMed

Yun, J; Cho, K-S

2016-12-01

Microbial community associated with hydrogen production and volatile fatty acids (VFAs) accumulation was characterized in acidogenic hydrogenesis using molasses wastewater as a feedstock. Hydrogen and VFAs production were measured under an organic loading rate (OLR) from 19 to 35 g-COD l -1  day -1 . The active microbial community was analysed using RNA-based massively parallel sequencing technique, and their correlation patterns were analysed using networking analysis. The continuous stirred tank reactor achieved stable hydrogen production at different OLR conditions, and the maximum hydrogen production rate (HPR) was 1·02 L-H 2  l -1  day -1 at 31·0 g-COD l -1  day -1 . Butyrate (50%) and acetate (38%) positively increased with increase in OLR. Total VFA production stayed around 7135 mg l -1 during the operation period. Although Clostridiales and Lactobacillales were relatively abundant, the HPR was positively associated with Pseudomonadaceae and Micrococcineae. Total VFA and acetate, butyrate and propionate concentrations were positively correlated with lactic acid bacteria (LAB) such as Bacillales, Sporolactobacillus and Lactobacillus. The close relationship between Pseudomonadaceae and Micrococcineae, and LAB play important roles for stable hydrogen and VFA production from molasses wastewater. Microbial information on hydrogen and VFA production can be useful to design and operate for acidogenic hydrogenesis using high strength molasses wastewater. © 2016 The Society for Applied Microbiology.

Stormwater runoff drives viral community composition changes in inland freshwaters

PubMed Central

Williamson, Kurt E.; Harris, Jamie V.; Green, Jasmin C.; Rahman, Faraz; Chambers, Randolph M.

2014-01-01

Storm events impact freshwater microbial communities by transporting terrestrial viruses and other microbes to freshwater systems, and by potentially resuspending microbes from bottom sediments. The magnitude of these impacts on freshwater ecosystems is unknown and largely unexplored. Field studies carried out at two discrete sites in coastal Virginia (USA) were used to characterize the viral load carried by runoff and to test the hypothesis that terrestrial viruses introduced through stormwater runoff change the composition of freshwater microbial communities. Field data gathered from an agricultural watershed indicated that primary runoff can contain viral densities approximating those of receiving waters. Furthermore, viruses attached to suspended colloids made up a large fraction of the total load, particularly in early stages of the storm. At a second field site (stormwater retention pond), RAPD-PCR profiling showed that the viral community of the pond changed dramatically over the course of two intense storms while relatively little change was observed over similar time scales in the absence of disturbance. Comparisons of planktonic and particle-associated viral communities revealed two completely distinct communities, suggesting that particle-associated viruses represent a potentially large and overlooked portion of aquatic viral abundance and diversity. Our findings show that stormwater runoff can quickly change the composition of freshwater microbial communities. Based on these findings, increased storms in the coastal mid-Atlantic region predicted by most climate change models will likely have important impacts on the structure and function of local freshwater microbial communities. PMID:24672520

Food safety knowledge and practices of abattoir and butchery shops and the microbial profile of meat in Mekelle City, Ethiopia

PubMed Central

Haileselassie, Mekonnen; Taddele, Habtamu; Adhana, Kelali; Kalayou, Shewit

2013-01-01

Objective To assess the food safety knowledge and practices in meat handling, and to determine microbial load and pathogenic organisms in meat at Mekelle city. Methods A descriptive survey design was used to answer questions concerning the current status of food hygiene and sanitation practiced in the abattoir and butcher shops. Workers from the abattoir and butcher shops were interviewed through a structured questionnaire to assess their food safety knowledge. Bacterial load was assessed by serial dilution method and the major bacterial pathogens were isolated by using standard procedures. Results 15.4% of the abattoir workers had no health certificate and there was no hot water, sterilizer and cooling facility in the abattoir. 11.3% of the butchers didn't use protective clothes. There was a food safety knowledge gap within the abattoir and butcher shop workers. The mean values of bacterial load of abattoir meat, butcher shops and street meat sale was found to be 1.1×105, 5.6×105 and 4.3×106 cfu/g, respectively. The major bacterial pathogens isolated were Escherichia coli, Staphylococcus aureus and Bacillus cereus. Conclusions The study revealed that there is a reasonable gap on food safety knowledge by abattoir and butcher shop workers. The microbial profile was also higher compared to standards set by World Health Organization. Due attention should be given by the government to improve the food safety knowledge and the quality standard of meat sold in the city. PMID:23646306

Multiwall carbon nanotubes increase the microbial community in crude oil contaminated fresh water sediments.

PubMed

Abbasian, Firouz; Lockington, Robin; Palanisami, Thavamani; Megharaj, Mallavarapu; Naidu, Ravi

2016-01-01

Since crude oil contamination is one of the biggest environmental concerns, its removal from contaminated sites is of interest for both researchers and industries. In situ bioremediation is a promising technique for decreasing or even eliminating crude oil and hydrocarbon contamination. However, since these compounds are potentially toxic for many microorganisms, high loads of contamination can inhibit the microbial community and therefore reduce the removal rate. Therefore, any strategy with the ability to increase the microbial population in such circumstances can be of promise in improving the remediation process. In this study, multiwall carbon nanotubes were employed to support microbial growth in sediments contaminated with crude oil. Following spiking of fresh water sediments with different concentrations of crude oil alone and in a mixture with carbon nanotubes for 30days, the microbial profiles in these sediments were obtained using FLX-pyrosequencing. Next, the ratios of each member of the microbial population in these sediments were compared with those values in the untreated control sediment. This study showed that combination of crude oil and carbon nanotubes can increase the diversity of the total microbial population. Furthermore, these treatments could increase the ratios of several microorganisms that are known to be effective in the degradation of hydrocarbons. Copyright © 2015 Elsevier B.V. All rights reserved.

Soil inoculation with microbial communities - can this become a useful tool in soil remediation?

NASA Astrophysics Data System (ADS)

Krug, Angelika; Wang, Fang; Dörfler, Ulrike; Munch, Jean Charles; Schroll, Reiner

2010-05-01

We artificially loaded different type of agricultural soils with model 14C-labelled chemicals, and we inoculated such soils with different microbial communities as well as isolated strains to enhance the mineralization of such chemicals. Inocula were introduced by different approaches: (i) soil inocula, (ii) application of isolated strain as well as microbial community via media, (iii) isolated strain as well as microbial community attached to a carrier material. Most of the inoculation experiments were conducted in laboratory but we also tested one of these approaches under real environmental conditions in lysimeters and we could show that the approach was successful. We already could show that inoculating soils with microbial communities attached on a specific carrier material shows the highest mineralization effectiveness and also the highest sustainability. Microbes attached on clay particles preserved their function over a long time period even if the specific microbial substrate was already degraded or at least not detectable any more. Additionally we already could show that in specific cases some soil parameters might reduce the effectiveness of such an approach. Results on isoproturon as a model for phenylurea-herbicides and 1,2,4-trichlorobenzene as an example for an industrially used chemical as well as the corresponding chemicals` degrading microbial communities and isolated strain will be presented.

Temporal variation in airborne microbial populations and microbially-derived allergens in a tropical urban landscape

NASA Astrophysics Data System (ADS)

Woo, Anthony C.; Brar, Manreetpal S.; Chan, Yuki; Lau, Maggie C. Y.; Leung, Frederick C. C.; Scott, James A.; Vrijmoed, Lilian L. P.; Zawar-Reza, Peyman; Pointing, Stephen B.

2013-08-01

The microbial component of outdoor aerosols was assessed along a gradient of urban development from inner-city to rural in the seasonal-tropical metropolis of Hong Kong. Sampling over a continuous one-year period was conducted, with molecular analyses to characterize bacterial and eukaryal microbial populations, immuno-assays to detect microbially-derived allergens and extensive environmental and meteorological observations. The data revealed bio-aerosol populations were not significantly impacted by the level of urban development as measured by anthropogenic pollutants and human population levels, but instead exhibited a strong seasonal trend related to general climatic variables. We applied back-trajectory analysis to establish sources of air masses and this allowed further explanation of urban bio-aerosols largely in terms of summer-marine and winter-continental origins. We also evaluated bio-aerosols for the potential to detect human health threats. Many samples supported bacterial and fungal phylotypes indicative of known pathogenic taxa, together with common indicators of human presence. The occurrence of allergenic endotoxins and beta-glucans generally tracked trends in microbial populations, with levels known to induce symptoms detected during summer months when microbial loading was higher. This strengthens calls for bio-aerosols to be considered in future risk assessments and surveillance of air quality, along with existing chemical and particulate indices.

Microbial Population Dynamics and Ecosystem Functions of Anoxic/Aerobic Granular Sludge in Sequencing Batch Reactors Operated at Different Organic Loading Rates

PubMed Central

Szabó, Enikö; Liébana, Raquel; Hermansson, Malte; Modin, Oskar; Persson, Frank; Wilén, Britt-Marie

2017-01-01

The granular sludge process is an effective, low-footprint alternative to conventional activated sludge wastewater treatment. The architecture of the microbial granules allows the co-existence of different functional groups, e.g., nitrifying and denitrifying communities, which permits compact reactor design. However, little is known about the factors influencing community assembly in granular sludge, such as the effects of reactor operation strategies and influent wastewater composition. Here, we analyze the development of the microbiomes in parallel laboratory-scale anoxic/aerobic granular sludge reactors operated at low (0.9 kg m-3d-1), moderate (1.9 kg m-3d-1) and high (3.7 kg m-3d-1) organic loading rates (OLRs) and the same ammonium loading rate (0.2 kg NH4-N m-3d-1) for 84 days. Complete removal of organic carbon and ammonium was achieved in all three reactors after start-up, while the nitrogen removal (denitrification) efficiency increased with the OLR: 0% at low, 38% at moderate, and 66% at high loading rate. The bacterial communities at different loading rates diverged rapidly after start-up and showed less than 50% similarity after 6 days, and below 40% similarity after 84 days. The three reactor microbiomes were dominated by different genera (mainly Meganema, Thauera, Paracoccus, and Zoogloea), but these genera have similar ecosystem functions of EPS production, denitrification and polyhydroxyalkanoate (PHA) storage. Many less abundant but persistent taxa were also detected within these functional groups. The bacterial communities were functionally redundant irrespective of the loading rate applied. At steady-state reactor operation, the identity of the core community members was rather stable, but their relative abundances changed considerably over time. Furthermore, nitrifying bacteria were low in relative abundance and diversity in all reactors, despite their large contribution to nitrogen turnover. The results suggest that the OLR has considerable impact on the composition of the granular sludge communities, but also that the granule communities can be dynamic even at steady-state reactor operation due to high functional redundancy of several key guilds. Knowledge about microbial diversity with specific functional guilds under different operating conditions can be important for engineers to predict the stability of reactor functions during the start-up and continued reactor operation. PMID:28507540

Good Manufacturing Practices and Microbial Contamination Sources in Orange Fleshed Sweet Potato Puree Processing Plant in Kenya

PubMed Central

Abong', George Ooko

2018-01-01

Limited information exists on the status of hygiene and probable sources of microbial contamination in Orange Fleshed Sweet Potato (OFSP) puree processing. The current study is aimed at determining the level of compliance to Good Manufacturing Practices (GMPs), hygiene, and microbial quality in OFSP puree processing plant in Kenya. Intensive observation and interviews using a structured GMPs checklist, environmental sampling, and microbial analysis by standard microbiological methods were used in data collection. The results indicated low level of compliance to GMPs with an overall compliance score of 58%. Microbial counts on food equipment surfaces, installations, and personnel hands and in packaged OFSP puree were above the recommended microbial safety and quality legal limits. Steaming significantly (P < 0.05) reduced microbial load in OFSP cooked roots but the counts significantly (P < 0.05) increased in the puree due to postprocessing contamination. Total counts, yeasts and molds, Enterobacteriaceae, total coliforms, and E. coli and S. aureus counts in OFSP puree were 8.0, 4.0, 6.6, 5.8, 4.8, and 5.9 log10 cfu/g, respectively. In conclusion, equipment surfaces, personnel hands, and processing water were major sources of contamination in OFSP puree processing and handling. Plant hygiene inspection, environmental monitoring, and food safety trainings are recommended to improve hygiene, microbial quality, and safety of OFSP puree. PMID:29808161

Good Manufacturing Practices and Microbial Contamination Sources in Orange Fleshed Sweet Potato Puree Processing Plant in Kenya.

PubMed

Malavi, Derick Nyabera; Muzhingi, Tawanda; Abong', George Ooko

2018-01-01

Limited information exists on the status of hygiene and probable sources of microbial contamination in Orange Fleshed Sweet Potato (OFSP) puree processing. The current study is aimed at determining the level of compliance to Good Manufacturing Practices (GMPs), hygiene, and microbial quality in OFSP puree processing plant in Kenya. Intensive observation and interviews using a structured GMPs checklist, environmental sampling, and microbial analysis by standard microbiological methods were used in data collection. The results indicated low level of compliance to GMPs with an overall compliance score of 58%. Microbial counts on food equipment surfaces, installations, and personnel hands and in packaged OFSP puree were above the recommended microbial safety and quality legal limits. Steaming significantly ( P < 0.05) reduced microbial load in OFSP cooked roots but the counts significantly ( P < 0.05) increased in the puree due to postprocessing contamination. Total counts, yeasts and molds, Enterobacteriaceae, total coliforms, and E. coli and S. aureus counts in OFSP puree were 8.0, 4.0, 6.6, 5.8, 4.8, and 5.9 log 10 cfu/g, respectively. In conclusion, equipment surfaces, personnel hands, and processing water were major sources of contamination in OFSP puree processing and handling. Plant hygiene inspection, environmental monitoring, and food safety trainings are recommended to improve hygiene, microbial quality, and safety of OFSP puree.

Performance and membrane fouling of a step-fed submerged membrane sequencing batch reactor treating swine biogas digestion slurry.

PubMed

Han, Zhiying; Chen, Shixia; Lin, Xiaochang; Yu, Hongjun; Duan, Li'an; Ye, Zhangying; Jia, Yanbo; Zhu, Songming; Liu, Dezhao

2018-01-02

To identify the performance of step-fed submerged membrane sequencing batch reactor (SMSBR) treating swine biogas digestion slurry and to explore the correlation between microbial metabolites and membrane fouling within this novel reactor, a lab-scale step-fed SMSBR was operated under nitrogen loading rate of 0.026, 0.052 and 0.062 g NH 4 + -N (gVSS·d) -1 . Results show that the total removal efficiencies for NH 4 + -N, total nitrogen and chemical oxygen demand in the reactor (>94%, >89% and >97%, respectively) were high during the whole experiment. However, the cycle removal efficiency of NH 4 + -N decreased significantly when the nitrogen loading rate was increased to 0.062 g NH 4 + -N (gVSS·d) -1 . The total removal efficiency of total phosphorus in the step-fed SMSBR was generally higher than 75%, though large fluctuations were observed during the experiments. In addition, the concentrations of microbial metabolites, i.e., soluble microbial products (SMP) and extracellular polymeric substances (EPS) from activated sludge increased as nitrogen loading rate increased, both showing quadratic equation correlations with viscosity of the mixed liquid in the step-fed SMSBR (both R 2 > 0.90). EPS content was higher than SMP content, while protein (PN) was detected as the main component in both SMP and EPS. EPS PN was found to be well correlated with transmembrane pressure, membrane flux and the total membrane fouling resistance. Furthermore, the three-dimensional excitation-emission matrix fluorescence spectroscopy results suggested the tryptophan-like protein as one of the main contributors to the membrane fouling. Overall, this study showed that the step-fed SMSBR could be used to treat swine digestion slurry at nitrogen loading rate of 0.052 g NH 4 + -N (gVSS·d) -1 , and the control strategy of membrane fouling should be developed based on reducing the tryptophan-like PN in EPS.

Colloid centrifugation of fresh stallion semen before cryopreservation decreased microorganism load of frozen-thawed semen without affecting seminal kinetics.

PubMed

Guimarães, T; Lopes, G; Pinto, M; Silva, E; Miranda, C; Correia, M J; Damásio, L; Thompson, G; Rocha, A

2015-01-15

Freezability of equine semen may be influenced by microorganism population of semen. The objective of this study was to verify the effect of single-layer density gradient centrifugation (SLC) of fresh semen before cryopreservation on semen's microbial load (ML) and sperm cells kinetics after freezing-thawing. For that, one ejaculate was collected from 20 healthy stallions and split into control (C) samples (cryopreserved without previous SLC) and SLC samples (subjected to SLC). Semen cryopreservation was performed according to the same protocol in both groups. Microbial load of each microorganism species and total microbial load (TML) expressed in colony-forming units (CFU/mL) as well as frozen-thawed sperm kinetics were assessed in both groups. Additional analysis of the TML was performed, subdividing the frozen-thawed samples in "suitable" (total motility ≥ 30%) and "unsuitable" (total motility < 30%) semen for freezing programs, and comparing the C and SLC groups within these subpopulations. After thawing, SLC samples had less (P < 0.05) TML (88.65 × 10(2) ± 83.8 × 10(2) CFU/mL) than C samples (155.69 × 10(2) ± 48.85 × 10(2) CFU/mL), mainly due to a reduction of Enterococcus spp. and Bacillus spp. A relationship between post-thaw motility and SLC effect on ML was noted, as only in samples with more than 30% total motility was ML reduced (P < 0.05) by SLC (from 51.33 × 10(2) ± 33.26 × 10(2) CFU/mL to 26.68 × 10(2) ± 12.39 × 10(2) CFU/mL in "suitable" frozen-thawed semen vs. 240.90 × 10(2) ± 498.20 × 10(2) to 139.30 × 10(2) ± 290.30 × 10(2) CFU/mL in "unsuitable" frozen-thawed semen). The effect of SLC on kinetics of frozen-thawed sperm cells was negligible. Copyright © 2015 Elsevier Inc. All rights reserved.

Foam soap is not as effective as liquid soap in eliminating hand microbial flora.

PubMed

Dixon, Nicolette; Morgan, Margie; Equils, Ozlem

2017-07-01

Foam soaps are aerosolized liquid soaps dispensed through a special pump mechanism. Currently there are no studies comparing liquid soap with foam soap in regard to efficacy of reducing hand microbial burden. In 3 separate experiments and with 2 different brands of foam soap, it was observed that nonantimicrobial foam soap was not as effective in reducing hand bacterial load as the liquid soap. Copyright © 2017 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

Wind, rain and bacteria: The effect of weather on the microbial composition of roof-harvested rainwater.

PubMed

Evans, C A; Coombes, P J; Dunstan, R H

2006-01-01

The microbiological and chemical quality of tank-stored rainwater is impacted directly by roof catchment and subsequent run-off contamination, via direct depositions by birds and small mammals, decay of accumulated organic debris, and atmospheric deposition of airborne micro-organisms and chemical pollutants. Previous literature reports on roof water quality have given little consideration to the relative significance of airborne micro-organisms. This study involved analyses of direct roof run-off at an urban housing development in Newcastle, on the east coast of Australia. A total of 77 samples were collected during 11 separate rainfall events, and microbial counts and mean concentrations of several ionic contaminants were matched to climatic data corresponding to each of the monitored events. Conditions both antecedent to, and those prevailing during each event, were examined to investigate the influence of certain meteorological parameters on the bacterial composition of the roof water and indirectly assess the relative contribution of airborne micro-organisms to the total bacterial load. Results indicated that airborne micro-organisms represented a significant contribution to the bacterial load of roof water at this site, and that the overall contaminant load was influenced by wind velocities, while the profile (composition) of the load varied with wind direction. The implications of these findings to the issues of tank water quality and health risk analysis, appropriate usage and system design are discussed.

Statistical summary of selected physical, chemical, and microbial characteristics, and estimates of constituent loads in urban stormwater, Maricopa County, Arizona

USGS Publications Warehouse

Lopes, T.J.; Fossum, K.D.; Phillips, J.V.; Monical, J.E.

1995-01-01

Stormwater and streamflow in the Phoenix, Arizona, area were monitored to determine the physical, chemical, and microbial characteristics of storm- water from areas having different land uses; to describe the characteristics of streamflow in a river that receives urban stormwater; and to estimate constituent loads in stormwater from unmonitored areas in Maricopa County, Arizona. Land use affects urban stormwater chemistry mostly because the percentage of impervious area controls the suspended-solids concentrations and varies with the type of land use. Urban activities also seem to concentrate cadmium, lead, and zinc in sediments. Urban stormwater had larger concentrations of chemical oxygen demand and biological oxygen demand, oil and grease, and higher counts of fecal bacteria than streamflow and could degrade the quality of the Salt River. Most regression equations for estimating constituent loads require three explanatory variables (total rainfall, drainage area, and per- centage of impervious area) and had standard errors that were from 65 to 266 percent. Localized areas that appear to contribute a large proportion of the constituent loads typically have 40 percent or more impervious area and are associated with industrial, commercial, and high-density residential land uses. The use of the mean value of the event-mean constituent concentrations measured in stormwater may be the best way of estimating constituent concentrations.

Quantitative Assessment of Antimicrobial Activity of PLGA Films Loaded with 4-Hexylresorcinol

PubMed Central

Kemme, Michael; Heinzel-Wieland, Regina

2018-01-01

Profound screening and evaluation methods for biocide-releasing polymer films are crucial for predicting applicability and therapeutic outcome of these drug delivery systems. For this purpose, we developed an agar overlay assay embedding biopolymer composite films in a seeded microbial lawn. By combining this approach with model-dependent analysis for agar diffusion, antimicrobial potency of the entrapped drug can be calculated in terms of minimum inhibitory concentrations (MICs). Thus, the topical antiseptic 4-hexylresorcinol (4-HR) was incorporated into poly(lactic-co-glycolic acid) (PLGA) films at different loadings up to 3.7 mg/cm2 surface area through a solvent casting technique. The antimicrobial activity of 4-HR released from these composite films was assessed against a panel of Gram-negative and Gram–positive bacteria, yeasts and filamentous fungi by the proposed assay. All the microbial strains tested were susceptible to PLGA-4-HR films with MIC values down to 0.4% (w/w). The presented approach serves as a reliable method in screening and quantifying the antimicrobial activity of polymer composite films. Moreover, 4-HR-loaded PLGA films are a promising biomaterial that may find future application in the biomedical and packaging sector. PMID:29324696

Enhancement in current density and energy conversion efficiency of 3-dimensional MFC anodes using pre-enriched consortium and continuous supply of electron donors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borole, Abhijeet P; Hamilton, Choo Yieng; Vishnivetskaya, Tatiana A

2011-01-01

Using a pre-enriched microbial consortium as the inoculum and continuous supply of carbon source, improvement in performance of a three-dimensional, flow-through MFC anode utilizing ferricyanide cathode was investigated. The power density increased from 170 W/m3 (1800 mW/m2) to 580 W/m3 (6130 mW/m2), when the carbon loading increased from 2.5 g/l-day to 50 g/l-day. The coulombic efficiency (CE) decreased from 90% to 23% with increasing carbon loading. The CEs are among the highest reported for glucose and lactate as the substrate with the maximum current density reaching 15.1 A/m2. This suggests establishment of a very high performance exoelectrogenic microbial consortium atmore » the anode. A maximum energy conversion efficiency of 54% was observed at a loading of 2.5 g/l-day. Biological characterization of the consortium showed presence of Burkholderiales and Rhodocyclales as the dominant members. Imaging of the biofilms revealed thinner biofilms compared to the inoculum MFC, but a 1.9-fold higher power density.« less

Deterministic mechanisms define the long-term anaerobic digestion microbiome and its functionality regardless of the initial microbial community.

PubMed

Peces, M; Astals, S; Jensen, P D; Clarke, W P

2018-05-17

The impact of the starting inoculum on long-term anaerobic digestion performance, process functionality and microbial community composition remains unclear. To understand the impact of starting inoculum, active microbial communities from four different full-scale anaerobic digesters were each used to inoculate four continuous lab-scale anaerobic digesters, which were operated identically for 295 days. Digesters were operated at 15 days solid retention time, an organic loading rate of 1 g COD L r -1 d -1 (75:25 - cellulose:casein) and 37 °C. Results showed that long-term process performance, metabolic rates (hydrolytic, acetogenic, and methanogenic) and microbial community are independent of the inoculum source. Digesters process performance converged after 80 days, while metabolic rates and microbial communities converged after 120-145 days. The convergence of the different microbial communities towards a core-community proves that the deterministic factors (process operational conditions) were a stronger driver than the initial microbial community composition. Indeed, the core-community represented 72% of the relative abundance among the four digesters. Moreover, a number of positive correlations were observed between higher metabolic rates and the relative abundance of specific microbial groups. These correlations showed that both substrate consumers and suppliers trigger higher metabolic rates, expanding the knowledge of the nexus between microorganisms and functionality. Overall, these results support that deterministic factors control microbial communities in bioreactors independently of the inoculum source. Hence, it seems plausible that a desired microbial composition and functionality can be achieved by tuning process operational conditions. Copyright © 2018. Published by Elsevier Ltd.

Electron beam irradiation of Matricaria chamomilla L. for microbial decontamination

NASA Astrophysics Data System (ADS)

Nemţanu, Monica R.; Kikuchi, Irene Satiko; de Jesus Andreoli Pinto, Terezinha; Mazilu, Elena; Setnic, Silvia; Bucur, Marcela; Duliu, Octavian G.; Meltzer, Viorica; Pincu, Elena

2008-05-01

Wild chamomile (Matricaria chamomilla L.) is one of the most popular herbal materials with both internal and external use to cure different health disturbances. As a consequence of its origin, chamomile could carry various microbial contaminants which offer different hazards to the final consumer. Reduction of the microbial load to the in force regulation limits represents an important phase in the technological process of vegetal materials, and the electron beam treatment might be an efficient alternative to the classical methods of hygienic quality assurance. The purpose of the study was to analyze the potential application of the electron beam treatment in order to assure the microbial safety of the wild chamomile. Samples of chamomile dry inflorescences were treated in electron beam (e-beam) of 6 MeV mean energy, at room temperature and ambient pressure. Some loss of the chemical compounds with bioactive role could be noticed, but the number of microorganisms decreased as a function on the absorbed dose. Consequently, the microbial quality of studied vegetal material inflorescences was improved by e-beam irradiation.

Mechanistic modelling of the inhibitory effect of pH on microbial growth.

PubMed

Akkermans, Simen; Van Impe, Jan F

2018-06-01

Modelling and simulation of microbial dynamics as a function of processing, transportation and storage conditions is a useful tool to improve microbial food safety and quality. The goal of this research is to improve an existing methodology for building mechanistic predictive models based on the environmental conditions. The effect of environmental conditions on microbial dynamics is often described by combining the separate effects in a multiplicative way (gamma concept). This idea was extended further in this work by including the effects of the lag and stationary growth phases on microbial growth rate as independent gamma factors. A mechanistic description of the stationary phase as a function of pH was included, based on a novel class of models that consider product inhibition. Experimental results on Escherichia coli growth dynamics indicated that also the parameters of the product inhibition equations can be modelled with the gamma approach. This work has extended a modelling methodology, resulting in predictive models that are (i) mechanistically inspired, (ii) easily identifiable with a limited work load and (iii) easily extended to additional environmental conditions. Copyright © 2017. Published by Elsevier Ltd.

Algae inhibition experiment and load characteristics of the algae solution

NASA Astrophysics Data System (ADS)

Xiong, L.; Gao, J. X.; Zhang, Y. X.; Yang, Z. K.; Zhang, D. Q.; He, W.

2016-08-01

It is necessary to inhibit microbial growth in an industrial cooling water system. This paper has developed a Monopolar/Bipolar polarity high voltage pulser with load adaptability for an algal experimental study. The load characteristics of the Chlorella pyrenoidosa solution were examined, and it was found that the solution load is resistive. The resistance is related to the plate area, concentration, and temperature of the solution. Furthermore, the pulser's treatment actually inhibits the algae cell growth. This article also explores the influence of various parameters of electric pulses on the algal effect. After the experiment, the optimum pulse parameters were determined to be an electric field intensity of 750 V/cm, a pulse width per second of 120μs, and monopolar polarity.

The potentiality of cross-linked fungal chitosan to control water contamination through bioactive filtration.

PubMed

Tayel, Ahmed A; El-Tras, Wael F; Elguindy, Nihal M

2016-07-01

Water contamination, with heavy metals and microbial pathogens, is among the most dangerous challenges that confront human health worldwide. Chitosan is a bioactive biopolymer that could be produced from fungal mycelia to be utilized in various applied fields. An attempt to apply fungal chitosan for heavy metals chelation and microbial pathogens inhibition, in contaminated water, was performed in current study. Chitosan was produced from the mycelia of Aspergillus niger, Cunninghamella elegans, Mucor rouxii and from shrimp shells, using unified production conditions. The FT-IR spectra of produced chitosans were closely comparable. M. rouxii chitosan had the highest deacetylation degree (91.3%) and the lowest molecular weight (33.2kDa). All chitosan types had potent antibacterial activities against Escherichia coli and Staphylococcus aureus; the most forceful type was C. elegans chitosan. Chitosan beads were cross-linked with glutaraldehyde (GLA) and ethylene-glycol-diglycidyl ether (EGDE); linked beads became insoluble in water, acidic and alkaline solutions and could effectively adsorb heavy metals ions, e.g. copper, lead and zinc, in aqueous solution. The bioactive filter, loaded with EGDE- A. niger chitosan beads, was able to reduce heavy metals' concentration with >68%, and microbial load with >81%, after 6h of continuous water flow in the experimentally designed filter. Copyright © 2016 Elsevier B.V. All rights reserved.

PubMed Central

Valeriani, F.; Cianfanelli, C.; Gianfranceschi, G.; Santucci, S.; Romano Spica, V.

2017-01-01

Summary Indoor Air Quality (IAQ) in libraries is influenced by the presence of specific factors which can impact on both paper storage as well as people health. Microclimatic conditions induce and support a biodiversity pattern involving environmental and anthropic microorganisms. We used a multidisciplinary monitoring model to characterize microflora biodiversity by Next Generation Sequencing (NGS). Biodiversity indexes were adapted to evaluate anthropic vs environmental pollution by combining Shannon mean index (H), species representativeness (EH), human/environmental pollution ratio (SA) to better characterize the NGS output and acquire synthetic information on Indoor Air Microbial Biodiversity (IAMB). Results indicate a frequently low microbial load (IGCM/m3 < 1000) characterized by different species (n = 102), including several cellulose metabolizing bacteria. Workers and visitors appeared a relevant source of microbial contamination. Air biodiversity assayed by NGS seems a promising marker for studying IAQ. PMID:29123371

Effects of gamma ray and electron beam irradiation on reduction of microbial load and antioxidant properties of Chum-Hed-Thet (Cassia alata (L.) Roxb.)

NASA Astrophysics Data System (ADS)

Prakhongsil, P.; Pewlong, W.; Sajjabut, S.; Chookaew, S.

2017-06-01

Considering the growing demands of herbal medicines, Cassia alata (L.) Roxb. has been reported to have various phytochemical activities. It has also been called in Thai as Chum-Hed-Thet. In this study, C. alata (L.) Roxb. powder were exposed to gamma and electron beam irradiation at doses of 0, 5, 10, 15 and 20 kGy. At the dose of 10 kGy, both of gamma and electron beam irradiation were sufficient in reducing microbial load of irradiated samples as specified in Thai pharmacopoeia (2005). These include the total aerobic microbial count of < 5.0x105 CFU/g, total fungi count of < 5.0x104 CFU/g, bile tolerant gram negative bacteria of < 104 (per g). In addition, pathogenic Clostridium spp. (per 10 g), Salmonella spp. (per 10 g), S. aureus (per 1g) and E.coli (per 1g) were absence. In terms of the bioactive molecules, the total phenolic content, DPPH free radical scavenging activity and ferric reducing antioxidant potential of unirradiated and irradiated samples were 19.32-22.44 mg gallic acid equivalent/g, 5.20-7.82 mg ascorbic acid equivalent/g and 69.46-82.06 μmol FeSO4/g, respectively. However, there were no significant differences between unirradiated and irradiated samples (p>0.05). Therefore, both of radiation by gamma ray or electron beam at 10 kGy was sufficient in elimination of microbial flora and did not significantly affected the total phenolic content and antioxidant activities of C. alata (L.) Roxb.

Effect of the Organic Loading Rate Increase and the Presence of Zeolite on Microbial Community Composition and Process Stability During Anaerobic Digestion of Chicken Wastes.

PubMed

Ziganshina, Elvira E; Belostotskiy, Dmitry E; Ilinskaya, Olga N; Boulygina, Eugenia A; Grigoryeva, Tatiana V; Ziganshin, Ayrat M

2015-11-01

This study investigates the effect of the organic loading rate (OLR) increase from 1.0 to 3.5 g VS L(-1) day(-1) at constant hydraulic retention time (HRT) of 35 days on anaerobic reactors' performance and microbial diversity during mesophilic anaerobic digestion of ammonium-rich chicken wastes in the absence/presence of zeolite. The effects of anaerobic process parameters on microbial community structure and dynamics were evaluated using a 16S ribosomal RNA gene-based pyrosequencing approach. Maximum 12 % of the total ammonia nitrogen (TAN) was efficiently removed by zeolite in the fixed zeolite reactor (day 87). In addition, volatile fatty acids (VFA) in the fixed zeolite reactor accumulated in lower concentrations at high OLR of 3.2-3.5 g VS L(-1) day(-1). Microbial communities in the fixed zeolite reactor and reactor without zeolite were dominated by various members of Bacteroidales and Methanobacterium sp. at moderate TAN and VFA levels. The increase of the OLR accompanied by TAN and VFA accumulation and increase in pH led to the predominance of representatives of the family Erysipelotrichaceae and genera Clostridium and Methanosarcina. Methanosarcina sp. reached relative abundances of 94 and 57 % in the fixed zeolite reactor and reactor without zeolite at the end of the experimental period, respectively. In addition, the diminution of Synergistaceae and Crenarchaeota and increase in the abundance of Acholeplasmataceae in parallel with the increase of TAN, VFA, and pH values were observed.

Microbial Dysbiosis Is Associated with Human Breast Cancer

PubMed Central

Xuan, Caiyun; Shamonki, Jaime M.; Chung, Alice; DiNome, Maggie L.; Chung, Maureen; Sieling, Peter A.; Lee, Delphine J.

2014-01-01

Breast cancer affects one in eight women in their lifetime. Though diet, age and genetic predisposition are established risk factors, the majority of breast cancers have unknown etiology. The human microbiota refers to the collection of microbes inhabiting the human body. Imbalance in microbial communities, or microbial dysbiosis, has been implicated in various human diseases including obesity, diabetes, and colon cancer. Therefore, we investigated the potential role of microbiota in breast cancer by next-generation sequencing using breast tumor tissue and paired normal adjacent tissue from the same patient. In a qualitative survey of the breast microbiota DNA, we found that the bacterium Methylobacterium radiotolerans is relatively enriched in tumor tissue, while the bacterium Sphingomonas yanoikuyae is relatively enriched in paired normal tissue. The relative abundances of these two bacterial species were inversely correlated in paired normal breast tissue but not in tumor tissue, indicating that dysbiosis is associated with breast cancer. Furthermore, the total bacterial DNA load was reduced in tumor versus paired normal and healthy breast tissue as determined by quantitative PCR. Interestingly, bacterial DNA load correlated inversely with advanced disease, a finding that could have broad implications in diagnosis and staging of breast cancer. Lastly, we observed lower basal levels of antibacterial response gene expression in tumor versus healthy breast tissue. Taken together, these data indicate that microbial DNA is present in the breast and that bacteria or their components may influence the local immune microenvironment. Our findings suggest a previously unrecognized link between dysbiosis and breast cancer which has potential diagnostic and therapeutic implications. PMID:24421902

THE EFFECT OF NITROGEN OVER-ENRICHMENT ON SOME PLANT-SOIL RELATIONSHIPS AND MICROBIAL PROCESSES

EPA Science Inventory

Salt marshes of similar geomorphology and hydrology with varying watershed nitrogen loads were examined for differences in plant structure, soil characteristics, and
denitrification. We observed landward encroachment of the low marsh Spartina alterniflora, and the displacement...

Ecological Forecasting: Microbial Contamination and Atmospheric Loadings of Nutrients to Land and Water

EPA Science Inventory

The development of ecological forecasts, namely, methodologies to predict the chemical, biological, and physical changes in terrestrial and aquatic ecosystems is desirable so that effective strategies for reducing the adverse impacts of human activities and extreme natural events...

Development and evaluation of garlic incorporated ready-to-eat extruded snacks.

PubMed

Haritha, D; Vijayalakshmi, V; Gulla, S

2014-11-01

The present study was carried out to develop and evaluate ready to eat extruded snacks incorporated with garlic powder at various levels (5 %, 10 %, 15 %, 20 %). The organoleptic evaluation was conducted for the developed products and the well accepted products were selected for further studies like physical properties and shelf life (stored at room temperature for 2 months). The organoleptic evaluation of the developed snacks revealed that 15 % and 20 % garlic incorporated snacks were not acceptable due to strong garlic flavor, therefore T1 (control), T2 (5 % garlic) and T3 ( 10 % garlic) were selected for further studies. The physical properties showed significant changes with incorporation of garlic powder at 0 %-10 % level. There was an increase in mass flow rate, tap density and bulk density but decrease in the water holding capacity, oil absorption capacity and expansion ratio. The water soluble index and moisture retention of the products showed the same values for all the three selected treatments. The products were packed by ordinary, nitrogen and vacuum packing and stored for 2 months. It was found that there was an increase in moisture content and microbial load, however the increase was within limits. The increase in the moisture content was low in nitrogen packed products where as the microbial load decreased with increase in the percentage of garlic incorporation. The nitrogen and vacuum packed products showed less microbial load than the ordinary packed products. Garlic powder can be incorporated at 5 and 10 % levels in ready-to-eat extruded snacks with well acceptability and can be stored for a period of 2 months with nitrogen packing as an effective packaging.

Microbial fuel cells for clogging assessment in constructed wetlands.

PubMed

Corbella, Clara; García, Joan; Puigagut, Jaume

2016-11-01

Clogging in HSSF CW may result in a reduction of system's life-span or treatment efficiency. Current available techniques to assess the degree of clogging in HSSF CW are time consuming and cannot be applied on a continuous basis. Main objective of this work was to assess the potential applicability of microbial fuel cells for continuous clogging assessment in HSSF CW. To this aim, two replicates of a membrane-less microbial fuel cell (MFC) were built up and operated under laboratory conditions for five weeks. The MFC anode was gravel-based to simulate the filter media of HSSF CW. MFC were weekly loaded with sludge that had been accumulating for several years in a pilot HSSF CW treating domestic wastewater. Sludge loading ranged from ca. 20kgTS·m(-3)CW·year(-1) at the beginning of the study period up to ca. 250kgTS·m(-3)CW·year(-1) at the end of the study period. Sludge loading applied resulted in sludge accumulated within the MFC equivalent to a clogging degree ranging from 0.2years (ca. 0.5kgTS·m(-3)CW) to ca. 5years (ca. 10kgTS·m(-3)CW). Results showed that the electric charge was negatively correlated to the amount of sludge accumulated (degree of clogging). Electron transference (expressed as electric charge) almost ceased when accumulated sludge within the MFC was equivalent to ca. 5years of clogging (ca. 10kgTS·m(-3)CW). This result suggests that, although longer study periods under more realistic conditions shall be further performed, HSSF CW operated as a MFC has great potential for clogging assessment. Copyright © 2016. Published by Elsevier B.V.

Rappaport-Vassiliadis medium for recovery of Salmonella spp. from low microbial load foods: collaborative study.

PubMed

Hammack, T S; Amaguaña, R M; Andrews, W H; Lerner, I

2001-01-01

Twenty-three laboratories participated in a collaborative study to compare the relative effectiveness of Rappaport-Vassiliadis (RV) medium incubated at 42 degrees C, selenite cystine (SC) broth (35 degrees C), and tetrathionate (TT) broth (35 and 43 degrees C) for recovery of Salmonella from the following foods with a low microbial load: dried egg yolk, dry active yeast, ground black pepper, guar gum, and instant nonfat dry milk. For dry active yeast, lauryl tryptose (LT) broth, incubated at 35 degrees C, was used instead of SC broth. All of the foods were artificially inoculated with single Salmonella serovars, that had been lyophilized before inoculation, at high and low target levels of 0.4 and 0.04 colony forming units/g food, respectively. For analysis of 870 test portions, representing all of the foods except yeast, 249 Salmonella-positive test portions were detected by RV medium, 265 by TT broth (43 degrees C), 268 by TT broth (35 degrees C), and 269 by SC broth (35 degrees C). For analysis of 225 test portions of yeast, 79 Salmonella-positive test portions were detected by RV medium, 79 by TT broth (43 degrees C), 84 by TT broth (35 degrees C), and 68 by LT broth (35 degrees C). RV medium was comparable to, or even more effective than, the other selective enrichments for recovery of Salmonella from all of the foods except guar gum. It is recommended that RV (42 degrees C) and TT (35 degrees C) be used with foods that have a low microbial load, except for guar gum for which SC (35 degrees C) and TT (35 degrees C) are recommended.

Long-Term Monitoring of Waterborne Pathogens and Microbial Source Tracking Markers in Paired Agricultural Watersheds under Controlled and Conventional Tile Drainage Management

PubMed Central

Wilkes, Graham; Brassard, Julie; Edge, Thomas A.; Gannon, Victor; Gottschall, Natalie; Jokinen, Cassandra C.; Jones, Tineke H.; Khan, Izhar U. H.; Marti, Romain; Sunohara, Mark D.; Topp, Edward

2014-01-01

Surface waters from paired agricultural watersheds under controlled tile drainage (CTD) and uncontrolled tile drainage (UCTD) were monitored over 7 years in order to determine if there was an effect of CTD (imposed during the growing season) on occurrences and loadings of bacterial and viral pathogens, coliphages, and microbial source tracking markers. There were significantly lower occurrences of human, ruminant, and livestock (ruminant plus pig) Bacteroidales markers in the CTD watershed in relation to the UCTD watershed. As for pathogens, there were significantly lower occurrences of Salmonella spp. and Arcobacter spp. in the CTD watershed. There were no instances where there were significantly higher quantitative loadings of any microbial target in the CTD watershed, except for F-specific DNA (F-DNA) and F-RNA coliphages, perhaps as a result of fecal inputs from a hobby farm independent of the drainage practice treatments. There was lower loading of the ruminant marker in the CTD watershed in relation to the UCTD system, and results were significant at the level P = 0.06. The odds of Salmonella spp. occurring increased when a ruminant marker was present relative to when the ruminant marker was absent, yet for Arcobacter spp., the odds of this pathogen occurring significantly decreased when a ruminant marker was present relative to when the ruminant marker was absent (but increased when a wildlife marker was present relative to when the wildlife marker was absent). Interestingly, the odds of norovirus GII (associated with human and swine) occurring in water increased significantly when a ruminant marker was present relative to when a ruminant marker was absent. Overall, this study suggests that fecal pollution from tile-drained fields to stream could be reduced by CTD utilization. PMID:24727274

Hydrogen production from switchgrass via an integrated pyrolysis-microbial electrolysis process.

PubMed

Lewis, A J; Ren, S; Ye, X; Kim, P; Labbe, N; Borole, A P

2015-11-01

A new approach to hydrogen production using an integrated pyrolysis-microbial electrolysis process is described. The aqueous stream generated during pyrolysis of switchgrass was used as a substrate for hydrogen production in a microbial electrolysis cell, achieving a maximum hydrogen production rate of 4.3 L H2/L anode-day at a loading of 10 g COD/L-anode-day. Hydrogen yields ranged from 50±3.2% to 76±0.5% while anode Coulombic efficiency ranged from 54±6.5% to 96±0.21%, respectively. Significant conversion of furfural, organic acids and phenolic molecules was observed under both batch and continuous conditions. The electrical and overall energy efficiency ranged from 149-175% and 48-63%, respectively. The results demonstrate the potential of the pyrolysis-microbial electrolysis process as a sustainable and efficient route for production of renewable hydrogen with significant implications for hydrocarbon production from biomass. Copyright © 2015 Elsevier Ltd. All rights reserved.

Two stage bioethanol refining with multi litre stacked microbial fuel cell and microbial electrolysis cell.

PubMed

Sugnaux, Marc; Happe, Manuel; Cachelin, Christian Pierre; Gloriod, Olivier; Huguenin, Gérald; Blatter, Maxime; Fischer, Fabian

2016-12-01

Ethanol, electricity, hydrogen and methane were produced in a two stage bioethanol refinery setup based on a 10L microbial fuel cell (MFC) and a 33L microbial electrolysis cell (MEC). The MFC was a triple stack for ethanol and electricity co-generation. The stack configuration produced more ethanol with faster glucose consumption the higher the stack potential. Under electrolytic conditions ethanol productivity outperformed standard conditions and reached 96.3% of the theoretically best case. At lower external loads currents and working potentials oscillated in a self-synchronized manner over all three MFC units in the stack. In the second refining stage, fermentation waste was converted into methane, using the scale up MEC stack. The bioelectric methanisation reached 91% efficiency at room temperature with an applied voltage of 1.5V using nickel cathodes. The two stage bioethanol refining process employing bioelectrochemical reactors produces more energy vectors than is possible with today's ethanol distilleries. Copyright © 2016 Elsevier Ltd. All rights reserved.

Acquisition and maturation of oral microbiome throughout childhood: An update

PubMed Central

Sampaio-Maia, Benedita; Monteiro-Silva, Filipa

2014-01-01

Traditional microbiology concepts are being renewed since the development of new microbiological technologies, such as, sequencing and large-scale genome analysis. Since the entry into the new millennium, a lot of new information has emerged regarding the oral microbiome. This revision presents an overview of this renewed knowledge on oral microbial community acquisition in the newborn and on the evolution of this microbiome to adulthood. Throughout childhood, the oral microbial load increases, but the microbial diversity decreases. The initial colonizers are related to the type of delivery, personal relationships, and living environment. These first colonizers seem to condition the subsequent colonization, which will lead to more complex and stable ecosystems in adulthood. These early oral microbial communities, therefore, play a major role in the development of the adult oral microbiota and may represent a source of both pathogenic and protective microorganisms in a very early stage of human life. The implications of this knowledge on the daily clinical practice of odontopediatrics are highlighted. PMID:25097637

Microbial community functional structures in wastewater treatment plants as characterized by GeoChip.

PubMed

Wang, Xiaohui; Xia, Yu; Wen, Xianghua; Yang, Yunfeng; Zhou, Jizhong

2014-01-01

Biological WWTPs must be functionally stable to continuously and steadily remove contaminants which rely upon the activity of complex microbial communities. However, knowledge is still lacking in regard to microbial community functional structures and their linkages to environmental variables. To investigate microbial community functional structures of activated sludge in wastewater treatment plants (WWTPs) and to understand the effects of environmental factors on their structure. 12 activated sludge samples were collected from four WWTPs in Beijing. A comprehensive functional gene array named GeoChip 4.2 was used to determine the microbial functional genes involved in a variety of biogeochemical processes such as carbon, nitrogen, phosphorous and sulfur cycles, metal resistance, antibiotic resistance and organic contaminant degradation. High similarities of the microbial community functional structures were found among activated sludge samples from the four WWTPs, as shown by both diversity indices and the overlapped genes. For individual gene category, such as egl, amyA, lip, nirS, nirK, nosZ, ureC, ppx, ppk, aprA, dsrA, sox and benAB, there were a number of microorganisms shared by all 12 samples. Canonical correspondence analysis (CCA) showed that the microbial functional patterns were highly correlated with water temperature, dissolved oxygen (DO), ammonia concentrations and loading rate of chemical oxygen demand (COD). Based on the variance partitioning analyses (VPA), a total of 53% of microbial community variation from GeoChip data can be explained by wastewater characteristics (25%) and operational parameters (23%), respectively. This study provided an overall picture of microbial community functional structures of activated sludge in WWTPs and discerned the linkages between microbial communities and environmental variables in WWTPs.

Microbial load and safety of paper currencies from some food vendors in Jimma Town, Southwest Ethiopia.

PubMed

Girma, Gosa; Ketema, Tsige; Bacha, Ketema

2014-11-25

Paper currency is used for every type of commerce and plays an important role in the life of human beings. However, the combination of its widespread use and constant exchange make paper currency a likely agent for disease transmission. Thus, the aim of this study was to evaluate the microbial load and safety of Ethiopian paper currencies collected from some food vendors in Jimma town. Standard microbiological methods were used for the enumeration of various microbial groups, isolation and characterization of pathogenic bacteria and their growth potential in selected weaning foods. A total of 100 samples of Ethiopian paper currencies, consisting of five denominations, from street food venders, hotels and cafeterias in Jimma town were collected aseptically. Sterile cotton swabs moistened with buffered peptone water solution were used for swabbing and the swabs were separately soaked into 10 ml sterile buffered peptone water solution. Mean microbial counts of Aerobic mesophilic bacteria, Staphylococci, Enterobacteriaceae, coliforms and Aerobic bacterial spores were (log CFU/cm2) 6.32, 4.43, 3.14, 2.98 and 3.78, respectively. However, mean counts of Yeasts and Moulds were below detectable levels. There was statistically significant variation (p<0.05) among the mean counts of microbes isolated from samples of paper currencies. The predominantly isolated microbial groups were Staphylococcus spp. (34.06%) followed by Bacillus spp. (31.88%), Enterobacteraceae (13.39%), Micrococcus spp. (9.55%) and Streptococcus spp. (9.03%). Overall, 25% and 10% of the samples were positive for S. aureus and Salmonella spp, respectively. In challenge study, Salmonella spp. and S. aureus reached the infective dose within 12 to 18 hours of inoculation. Thus, paper currencies could be considered as one of the possible vehicles for transmission of disease causing microorganisms. Poor handling practices and personal hygiene of the food vendors could contribute to the observed microbial counts. Thus, it calls for awareness development on the potential risks associated with poor handling of paper currencies at all level of the food establishments.

The bacterial biota of laboratory-reared edible mealworms (Tenebrio molitor L.): From feed to frass.

PubMed

Osimani, Andrea; Milanović, Vesna; Cardinali, Federica; Garofalo, Cristiana; Clementi, Francesca; Pasquini, Marina; Riolo, Paola; Ruschioni, Sara; Isidoro, Nunzio; Loreto, Nino; Franciosi, Elena; Tuohy, Kieran; Petruzzelli, Annalisa; Foglini, Martina; Gabucci, Claudia; Tonucci, Franco; Aquilanti, Lucia

2018-05-02

Tenebrio molitor represents one of the most popular species used for the large-scale conversion of plant biomass into protein and is characterized by high nutritional value. In the present laboratory study, the bacterial biota characterizing a pilot production chain of fresh T. molitor larvae was investigated. To this end, different batches of fresh mealworm larvae, their feeding substrate (wheatmeal) and frass were analyzed by viable microbial counts, PCR-DGGE and Illumina sequencing. Moreover, the occurrence of Coxiella burnetii, Pseudomonas aeruginosa and Shiga toxin-producing E. coli (STEC) was assessed through qualitative real-time PCR assays. Microbial viable counts highlighted low microbial contamination of the wheatmeal, whereas larvae and frass were characterized by high loads of Enterobacteriaceae, lactic acid bacteria, and several species of mesophilic aerobes. Spore-forming bacteria were detected to a lesser extent in all the samples. The combined molecular approach used to profile the microbiota confirmed the low microbial contamination of wheatmeal and allowed the detection of Enterobacter spp., Erwinia spp., Enterococcus spp. and Lactococcus spp. as dominant genera in both larvae and frass. Moreover, Klebsiella spp., Pantoea spp., and Xenorhabdus spp. were found to be in the minority. Entomoplasmatales (including Spiroplasma spp.) constituted a major fraction of the microbiota of one batch of larvae. From the real-time PCR assays, no sample was positive for either C. burnetii or STEC, whereas P. aeruginosa was detected in one sample of frass. Based on the overall results, two sources of microbial contamination were hypothesized, namely feeding with wheatmeal and vertical transmission of microorganisms from mother to offspring. Since mealworms are expected to be eaten as a whole, the overall outcomes collected in this laboratory study discourage the consumption of fresh mealworm larvae. Moreover, microbial loads and the absence of potential pathogens known to be associated with this insect species should be carefully assessed in order to reduce the minimum risk for consumers, by identifying the most opportune processing methods (e.g., boiling, frying, drying, etc.). Copyright © 2018 Elsevier B.V. All rights reserved.

Possible association between celiac disease and bacterial transglutaminase in food processing: a hypothesis

PubMed Central

Matthias, Torsten

2015-01-01

The incidence of celiac disease is increasing worldwide, and human tissue transglutaminase has long been considered the autoantigen of celiac disease. Concomitantly, the food industry has introduced ingredients such as microbial transglutaminase, which acts as a food glue, thereby revolutionizing food qualities. Several observations have led to the hypothesis that microbial transglutaminase is a new environmental enhancer of celiac disease. First, microbial transglutaminase deamidates/transamidates glutens such as the endogenous human tissue transglutaminase. It is capable of crosslinking proteins and other macromolecules, thereby changing their antigenicity and resulting in an increased antigenic load presented to the immune system. Second, it increases the stability of protein against proteinases, thus diminishing foreign protein elimination. Infections and the crosslinked nutritional constituent gluten and microbial transglutaminase increase the permeability of the intestine, where microbial transglutaminases are necessary for bacterial survival. The resulting intestinal leakage allows more immunogenic foreign molecules to induce celiac disease. The increased use of microbial transglutaminase in food processing may promote celiac pathogenesis ex vivo, where deamidation/transamidation starts, possibly explaining the surge in incidence of celiac disease. If future research substantiates this hypothesis, the findings will affect food product labeling, food additive policies of the food industry, and consumer health education. PMID:26084478

Bacterial dynamics in steady-state biofilters: beyond functional stability.

PubMed

Cabrol, Léa; Malhautier, Luc; Poly, Franck; Lepeuple, Anne-Sophie; Fanlo, Jean-Louis

2012-01-01

The spatial and temporal dynamics of microbial community structure and function were surveyed in duplicated woodchip-biofilters operated under constant conditions for 231 days. The contaminated gaseous stream for treatment was representative of composting emissions, included ammonia, dimethyl disulfide and a mixture of five oxygenated volatile organic compounds. The community structure and diversity were investigated by denaturing gradient gel electrophoresis on 16S rRNA gene fragments. During the first 42 days, microbial acclimatization revealed the influence of operating conditions and contaminant loading on the biofiltration community structure and diversity, as well as the limited impact of inoculum compared to the greater persistence of the endogenous woodchip community. During long-term operation, a high and stable removal efficiency was maintained despite a highly dynamic microbial community, suggesting the probable functional redundancy of the community. Most of the contaminant removal occurred in the first compartment, near the gas inlet, where the microbial diversity was the highest. The stratification of the microbial structures along the filter bed was statistically correlated to the longitudinal distribution of environmental conditions (selective pressure imposed by contaminant concentrations) and function (contaminant elimination capacity), highlighting the central role of the bacterial community. The reproducibility of microbial succession in replicates suggests that the community changes were presumably driven by a deterministic process.

Physical Factors Correlate to Microbial Community Structure and Nitrogen Cycling Gene Abundance in a Nitrate Fed Eutrophic Lagoon.

PubMed

Highton, Matthew P; Roosa, Stéphanie; Crawshaw, Josie; Schallenberg, Marc; Morales, Sergio E

2016-01-01

Nitrogenous run-off from farmed pastures contributes to the eutrophication of Lake Ellesmere, a large shallow lagoon/lake on the east coast of New Zealand. Tributaries periodically deliver high loads of nitrate to the lake which likely affect microbial communities therein. We hypothesized that a nutrient gradient would form from the potential sources (tributaries) creating a disturbance resulting in changes in microbial community structure. To test this we first determined the existence of such a gradient but found only a weak nitrogen (TN) and phosphorous gradient (DRP). Changes in microbial communities were determined by measuring functional potential (quantification of nitrogen cycling genes via nifH , nirS , nosZI , and nosZII using qPCR), potential activity (via denitrification enzyme activity), as well as using changes in total community (via 16S rRNA gene amplicon sequencing). Our results demonstrated that changes in microbial communities at a phylogenetic (relative abundance) and functional level (proportion of the microbial community carrying nifH and nosZI genes) were most strongly associated with physical gradients (e.g., lake depth, sediment grain size, sediment porosity) and not nutrient concentrations. Low nitrate influx at the time of sampling is proposed as a factor contributing to the observed patterns.

The effect of poultry manure application rate and AlCl(3) treatment on bacterial fecal indicators in runoff.

PubMed

Brooks, J P; Adeli, A; McLaughlin, M R; Miles, D M

2012-12-01

Increasing costs associated with inorganic fertilizer have led to widespread use of broiler litter. Proper land application, typically limiting nutrient loss, is essential to protect surface water. This study was designed to evaluate litter-borne microbial runoff (heterotrophic plate count bacteria, staphylococci, Escherichia coli, enterococci, and Clostridium perfringens) while applying typical nutrient-control methods. Field studies were conducted in which plots with high and low litter rates, inorganic fertilizer, AlCl(3)-treated litter, and controls were rained on five times using a rain generator. Overall, microbial runoff from poultry litter applied plots was consistently greater (2-5 log(10) plot(-1)) than controls. No appreciable effect on microbial runoff was noted from variable litter application rate or AlCl(3) treatments, though rain event, not time, significantly affected runoff load. C. perfringens and staphylococci runoff were consistently associated with poultry litter application, during early rain events, while other indicators were unreliable. Large microbial runoff pulses were observed, ranging from 10(2) to 10(10) CFU plot(-1); however, only a small fraction of litter-borne microbes were recoverable in runoff. This study indicated that microbial runoff from litter-applied plots can be substantial, and that methods intended to reduce nutrient losses do not necessarily reduce microbial runoff.

Microbial source tracking: a forensic technique for microbial source identification?

PubMed

Stapleton, Carl M; Wyer, Mark D; Kay, David; Crowther, John; McDonald, Adrian T; Walters, Martin; Gawler, Andrew; Hindle, Terry

2007-05-01

As the requirements of the Water Framework Directive (WFD) and the US Clean Water Act (USCWA) for the maintenance of microbiological water quality in 'protected areas' highlight, there is a growing recognition that integrated management of point and diffuse sources of microbial pollution is essential. New information on catchment microbial dynamics and, in particular, the sources of faecal indicator bacteria found in bathing and shellfish harvesting waters is a pre-requisite for the design of any 'programme of measures' at the drainage basin scale to secure and maintain compliance with existing and new health-based microbiological standards. This paper reports on a catchment-scale microbial source tracking (MST) study in the Leven Estuary drainage basin, northwest England, an area for which quantitative faecal indicator source apportionment empirical data and land use information were also collected. Since previous MST studies have been based on laboratory trials using 'manufactured' samples or analyses of spot environmental samples without the contextual microbial flux data (under high and low flow conditions) and source information, such background data are needed to evaluate the utility of MST in USCWA total maximum daily load (TMDL) assessments or WFD 'Programmes of Measures'. Thus, the operational utility of MST remains in some doubt. The results of this investigation, using genotyping of Bacteroidetes using polymerase chain reaction (PCR) and male-specific ribonucleic acid coliphage (F + RNA coliphage) using hybridisation, suggest some discrimination is possible between livestock- and human-derived faecal indicator concentrations but, in inter-grade areas, the degree to which the tracer picture reflected the land use pattern and probable faecal indicator loading were less distinct. Interestingly, the MST data was more reliable on high flow samples when much of the faecal indicator flux from catchment systems occurs. Whilst a useful supplementary tool, the MST information did not provide quantitative source apportionment for the study catchment. Thus, it could not replace detailed empirical measurement of microbial flux at key catchment outlets to underpin faecal indicator source apportionment. Therefore, the MST techniques reported herein currently may not meet the standards required to be a useful forensic tool, although continued development of the methods and further catchment scale studies could increase confidence in such methods for future application.

Expression of chloroperoxidase from Pseudomonas pyrrocinia in tobacco plastids for fungal resistance

USDA-ARS?s Scientific Manuscript database

While genetic improvement of susceptible crop species may enhance resistance to microbial pathogens and facilitate reduced pesticide load, the possibility for transmission of novel genes to wild relatives has hampered acceptance of genetically modified (GM) crops in some markets. Chloroplast transf...

MICROBIAL ENZYME ACTIVITIES IN A FRESHWATER MARSH AFTER CESSATION OF NUTRIENT LOADING. (R827641)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

THE EPA MICROBIAL SOURCE TRACKING DOCUMENT

EPA Science Inventory

Beach closures or violations of total maximum daily loads of fecal organisms in watersheds frequently generate a need to identify the major sources of contamination or, at least, determine whether the source is human or animal. A few years ago E. coli ribotyping was the only met...

Influence of the fuel and dosage on the performance of double-compartment microbial fuel cells.

PubMed

Asensio, Y; Fernandez-Marchante, C M; Lobato, J; Cañizares, P; Rodrigo, M A

2016-08-01

This manuscript focuses on the evaluation of the use of different types and dosages of fuels in the performance of double-compartment microbial fuel cell equipped with carbon felt electrodes and cationic membrane. Five types of fuels (ethanol, glycerol, acetate, propionate and fructose) have been tested for the same organic load (5,000 mg L(-1) measured as COD) and for one of them (acetate), the range of dosages between 500 and 20,000 mg L(-1) of COD was also studied. Results demonstrate that production of electricity depends strongly on the fuel used. Carboxylic acids are much more efficient than alcohols or fructose for the same organic load and within the range 500-5,000 mg L(-1) of acetate the production of electricity increases linearly with the amount of acetate fed but over these concentrations a change in the population composition may explain a worse performance. Copyright © 2016 Elsevier Ltd. All rights reserved.

Sonication improves kasturi lime (Citrus microcarpa) juice quality.

PubMed

Bhat, Rajeev; Kamaruddin, Nor Shuaidda Bt Che; Min-Tze, Liong; Karim, A A

2011-11-01

Freshly squeezed kasturi lime fruit juice was sonicated (for 0, 30 and 60min at 20°C, 25kHz frequency) to evaluate its impact on selected physico-chemical and antioxidant properties, such as pH, °Brix, titratable acidity, Hunter color values (L(∗), a(∗), b(∗)), ascorbic acid, DPPH radical scavenging activity, total phenolics, antioxidant capacity, flavonoids and flavonols. Additionally, the effect of sonication treatments on the microbial load (TPC, yeast and mold) were also evaluated. Sonication of juice samples for 60min showed enhancement in most of the bioactive compounds compared to samples treated for 30min and control samples (untreated). Significant reductions in the microbial load corresponding to sonication time were also recorded. Results of the present study indicate that sonication may be employed as a suitable technique for kasturi lime juice processing, where antioxidant and other bioactive compound retention or enhancement is desired, along with the achievement of safety and quality standards. Copyright © 2011 Elsevier B.V. All rights reserved.

Need for optimizing catalyst loading for achieving affordable microbial fuel cells.

PubMed

Singh, Inderjeet; Chandra, Amreesh

2013-08-01

Microbial fuel cell (MFC) technology is a promising technology for electricity production together with simultaneous water treatment. Catalysts play an important role in deciding the MFC performance. In most reports, effect of catalyst - both type and quantity is not optimized. In this paper, synthesis of nanorods of MnO2-catalyst particles for application in Pt-free MFCs is reported. The effect of catalyst loading i.e., weight ratio, with respect to conducting element and binder has been optimized by employing large number of combinations. Using simple theoretical model, it is shown that too high (or low) concentration of catalysts result in loss of MFC performance. The operation of MFC has been investigated using domestic wastewater as source of bio-waste for obtaining real world situation. Maximum power density of ∼61 mW/m(2) was obtained when weight ratio of catalyst and conducting species was 1:1. Suitable reasons are given to explain the outcomes. Copyright © 2013 Elsevier Ltd. All rights reserved.

Microbial Safety Improvement of Sea Buckthorn by Electron Beam Irradiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nemtanu, Monica R.; Minea, R.; Mazilu, Elena

2007-04-23

The commercialization of medicinal plants and/or their products is highly increased in Romania lately. One of the most used herbs is sea buckthorn being well known for its quality with a large potential for curing some diseases. Sea buckthorn can be contaminated with undesirable microorganisms which may affect negatively its quality. The paper presents the results regarding the action of a non-conventional technology meaning electron beam technique on sea buckthorn in order to improve its microbiological quality. Our study revealed that the sea buckthorn microbial load has been improved after 3 kGy irradiation keeping its active principles.

Microbial Safety Improvement of Sea Buckthorn by Electron Beam Irradiation

NASA Astrophysics Data System (ADS)

Nemţanu, Monica R.; Minea, R.; Mazilu, Elena; Rǎdulescu, Nora

2007-04-01

The commercialization of medicinal plants and/or their products is highly increased in Romania lately. One of the most used herbs is sea buckthorn being well known for its quality with a large potential for curing some diseases. Sea buckthorn can be contaminated with undesirable microorganisms which may affect negatively its quality. The paper presents the results regarding the action of a non-conventional technology meaning electron beam technique on sea buckthorn in order to improve its microbiological quality. Our study revealed that the sea buckthorn microbial load has been improved after 3 kGy irradiation keeping its active principles.

Microbial Load in Septic and Aseptic Procedure Rooms.

PubMed

Harnoss, Julian-Camill; Assadian, Ojan; Diener, Markus Karl; Müller, Thomas; Baguhl, Romy; Dettenkofer, Markus; Scheerer, Lukas; Kohlmann, Thomas; Heidecke, Claus-Dieter; Gessner, Stephan; Büchler, Markus Wolfgang; Kramer, Axel

2017-07-10

Highly effective measures to prevent surgical wound infections have been established over the last two decades. We studied whether the strict separation of septic and aseptic procedure rooms is still necessary. In an exploratory, prospective observational study, the microbial concentration in an operating room without a room ventilating system (RVS) was analyzed during 16 septic and 14 aseptic operations with the aid of an air sampler (50 cm and 1 m from the operative field) and sedimentation plates (1 m from the operative field, and contact culture on the walls). The means and standard deviations of the microbial loads were compared with the aid of GEE models (generalized estimation equations). In the comparison of septic and aseptic operations, no relevant differences were found with respect to the overall microbial concentration in the room air (401.7 ± 176.3 versus 388.2 ± 178.3 CFU/m 3 ; p = 0.692 [CFU, colony-forming units]) or sedimentation 1 m from the operative field (45.3 ± 22.0 versus 48.7 ± 18.5 CFU/m 2 /min; p = 0.603) and on the walls (35.7 ± 43.7 versus 29.0 ± 49.4 CFU/m 2 /min; p = 0.685). The only relevant differences between the microbial spectra associated with the two types of procedure were a small amount of sedimentation of Escherichia coli and Enterococcus faecalis in septic operations, and of staphylococcus aureus and pseudomonas stutzeri in aseptic operations, up to 30 minutes after the end of the procedure. These data do not suggest that septic and aseptic procedure rooms need to be separated. In interpreting the findings, one should recall that the study was not planned as an equivalence or non-inferiority study. Wherever patient safety is concerned, high-level safety concepts should only be demoted to lower levels if new and convincing evidence becomes available.

Bifunctional viscous nanovesicles co-loaded with resveratrol and gallic acid for skin protection against microbial and oxidative injuries.

PubMed

Vitonyte, Justina; Manca, Maria Letizia; Caddeo, Carla; Valenti, Donatella; Peris, Josè Esteban; Usach, Iris; Nacher, Amparo; Matos, Maria; Gutiérrez, Gemma; Orrù, Germano; Fernàndez-Busquets, Xavier; Fadda, Anna Maria; Manconi, Maria

2017-05-01

Resveratrol and gallic acid were co-loaded in phospholipid vesicles aiming at protecting the skin from external injuries, such as oxidative stress and microbial infections. Liposomes were prepared using biocompatible phospholipids dispersed in water. To improve vesicle stability and applicability, the phospholipids and the phenols were dispersed in water/propylene glycol or water/glycerol, thus obtaining PEVs and glycerosomes, respectively. The vesicles were characterized by size, morphology, physical stability, and their therapeutic efficacy was investigated in vitro. The vesicles were spherical, unilamellar and small in size: liposomes and glycerosomes were around 70nm in diameter, while PEVs were larger (∼170nm). The presence of propylene glycol or glycerol increased the viscosity of the vesicle systems, positively affecting their stability. The ability of the vesicles to promote the accumulation of the phenols (especially gallic acid) in the skin was demonstrated, as well as their low toxicity and great ability to protect keratinocytes and fibroblasts from oxidative damage. Additionally, an improvement of the antimicrobial activity of the phenols was shown against different skin pathogens. The co-loading of resveratrol and gallic acid in modified phospholipid vesicles represents an innovative, bifunctional tool for preventing and treating skin affections. Copyright © 2017 Elsevier B.V. All rights reserved.

Molecular analysis of microbial diversity in advanced caries.

PubMed

Chhour, Kim-Ly; Nadkarni, Mangala A; Byun, Roy; Martin, F Elizabeth; Jacques, Nicholas A; Hunter, Neil

2005-02-01

Real-time PCR analysis of the total bacterial load in advanced carious lesions has shown that the total load exceeds the number of cultivable bacteria. This suggests that an unresolved complexity exists in bacteria associated with advanced caries. In this report, the profile of the microflora of carious dentine was explored by using DNA extracted from 10 lesions selected on the basis of comparable total microbial load and on the relative abundance of Prevotella spp. Using universal primers for the 16S rRNA gene, PCR amplicons were cloned, and approximately 100 transformants were processed for each lesion. Phylogenetic analysis of 942 edited sequences demonstrated the presence of 75 species or phylotypes in the 10 carious lesions. Up to 31 taxa were represented in each sample. A diverse array of lactobacilli were found to comprise 50% of the species, with prevotellae also abundant, comprising 15% of the species. Other taxa present in a number of lesions or occurring with high abundance included Selenomonas spp., Dialister spp., Fusobacterium nucleatum, Eubacterium spp., members of the Lachnospiraceae family, Olsenella spp., Bifidobacterium spp., Propionibacterium sp., and Pseudoramibacter alactolyticus. The mechanisms by which such diverse patterns of bacteria extend carious lesions, including the aspect of infection of the vital dental pulp, remain unclear.

Nitrifying biomass characterization and monitoring during bioaugmentation in a membrane bioreactor.

PubMed

D'Anteo, Sibilla; Mannucci, Alberto; Meliani, Matteo; Verni, Franco; Petroni, Giulio; Munz, Giulio; Lubello, Claudio; Mori, Gualtiero; Vannini, Claudia

2015-01-01

A membrane bioreactor (MBR), fed with domestic wastewater, was bioaugmented with nitrifying biomass selected in a side-stream MBR fed with a synthetic high nitrogen-loaded influent. Microbial communities evolution was monitored and comparatively analysed through an extensive bio-molecular investigation (16S rRNA gene library construction and terminal-restriction fragment length polymorphism techniques) followed by statistical analyses. As expected, a highly specialized nitrifying biomass was selected in the side-stream reactor fed with high-strength ammonia synthetic wastewater. The bioaugmentation process caused an increase of nitrifying bacteria of the genera Nitrosomonas (up to more than 30%) and Nitrobacter in the inoculated MBR reactor. The overall structure of the microbial community changed in the mainstream MBR as a result of bioaugmentation. The effect of bioaugmentation in the shift of the microbial community was also verified through statistical analysis.

Nanoporous Mo2C functionalized 3D carbon architecture anode for boosting flavins mediated interfacial bioelectrocatalysis in microbial fuel cells

NASA Astrophysics Data System (ADS)

Zou, Long; Lu, Zhisong; Huang, Yunhong; Long, Zhong-er; Qiao, Yan

2017-08-01

An efficient microbial electrocatalysis in microbial fuel cells (MFCs) needs both high loading of microbes (biocatalysts) and robust interfacial electron transfer from microbes to electrode. Herein a nanoporous molybdenum carbide (Mo2C) functionalized carbon felt electrode with rich 3D hierarchical porous architecture is applied as MFC anode to achieve superior electrocatalytic performance. The nanoporous Mo2C functionalized anode exhibits strikingly improved microbial electrocatalysis in MFCs with 5-fold higher power density and long-term stability of electricity production. The great enhancement is attributed to the introduction of rough Mo2C nanostructural interface into macroporous carbon architecture for promoting microbial growth with great excretion of endogenous electron shuttles (flavins) and rich available nanopores for enlarging electrochemically active surface area. Importantly, the nanoporous Mo2C functionalized anode is revealed for the first time to have unique electrocatalytic activity towards redox reaction of flavins with more negative redox potential, indicating a more favourable thermodynamic driving force for anodic electron transfer. This work not only provides a promising electrode for high performance MFCs but also brings up a new insight into the effect of nanostructured materials on interfacial bioelectrocatalysis.

A review on the application of inorganic nano-structured materials in the modification of textiles: focus on anti-microbial properties.

PubMed

Dastjerdi, Roya; Montazer, Majid

2010-08-01

Textiles can provide a suitable substrate to grow micro-organisms especially at appropriate humidity and temperature in contact to human body. Recently, increasing public concern about hygiene has been driving many investigations for anti-microbial modification of textiles. However, using many anti-microbial agents has been avoided because of their possible harmful or toxic effects. Application of inorganic nano-particles and their nano-composites would be a good alternative. This review paper has focused on the properties and applications of inorganic nano-structured materials with good anti-microbial activity potential for textile modification. The discussed nano-structured anti-microbial agents include TiO(2) nano-particles, metallic and non-metallic TiO(2) nano-composites, titania nanotubes (TNTs), silver nano-particles, silver-based nano-structured materials, gold nano-particles, zinc oxide nano-particles and nano-rods, copper nano-particles, carbon nanotubes (CNTs), nano-clay and its modified forms, gallium, liposomes loaded nano-particles, metallic and inorganic dendrimers nano-composite, nano-capsules and cyclodextrins containing nano-particles. This review is also concerned with the application methods for the modification of textiles using nano-structured materials. Copyright 2010 Elsevier B.V. All rights reserved.

Cold Spots in Neonatal Incubators Are Hot Spots for Microbial Contamination▿

PubMed Central

de Goffau, Marcus C.; Bergman, Klasien A.; de Vries, Hendrik J.; Meessen, Nico E. L.; Degener, John E.; van Dijl, Jan Maarten; Harmsen, Hermie J. M.

2011-01-01

Thermal stability is essential for the survival and well-being of preterm neonates. This is achieved in neonatal incubators by raising the ambient temperature and humidity to sufficiently high levels. However, potentially pathogenic microorganisms also can thrive in such warm and humid environments. We therefore investigated whether the level of microbial contamination (i.e., the bacterial load) inside neonatal incubators can be predicted on the basis of their average temperature and relative humidity settings, paying special attention to local temperature differences. Swab samples were taken from the warmest and coldest spots found within Caleo incubators, and these were plated to determine the number of microbial CFU per location. In incubators with high average temperature (≥34°C) and relative humidity (≥60%) values, the level of microbial contamination was significantly higher at cold spots than at hot spots. This relates to the fact that the local equilibrium relative humidity at cold spots is sufficiently high to sustain microbial growth. The abundance of staphylococci, which are the main causative agents of late-onset sepsis in preterm neonates, was found to be elevated significantly in cold areas. These findings can be used to improve basic incubator hygiene. PMID:22003021

The nanostructure of microbially-reduced graphene oxide fosters thick and highly-performing electrochemically-active biofilms

NASA Astrophysics Data System (ADS)

Virdis, Bernardino; Dennis, Paul G.

2017-07-01

Biofilms of electrochemically-active organisms are used in microbial electrochemical technologies (METs) to catalyze bioreactions otherwise not possible at bare electrodes. At present, however, achievable current outputs are still below levels considered sufficient for economic viability of large-scale METs implementations. Here, we report three-dimensional, self-aggregating biofilm composites comprising of microbial cells embedded with microbially-reduced graphene oxide (rGO) nanoparticles to form a thick macro-porous network with superior electrochemical properties. In the presence of metabolic substrate, these hybrid biofilms are capable of producing up to five times more catalytic current than the control biofilms. Cyclic voltammetry, linear sweep voltammetry, and electrochemical impedance spectroscopy, show that in spite of the increased thickness, the biofilms amended with GO display lower polarization/charge transfer resistance compared to the controls, which we ascribe to the incorporation of rGO into the biofilms, which (1) promotes fast electron transfer, yet conserving a macroporous structure that allows free diffusion of reactants and products, and (2) enhances the interfacial dynamics by allowing a higher load of microbial cells per electrode surface area. These results suggest an easy-to-apply and cost-effective method to produce high-performing electrochemically-active biofilms in situ.

Assessing the microbial quality of a tropical watershed with an urbanization gradient using traditional and alternate fecal indicators.

PubMed

Santiago-Rodriguez, Tasha M; Toranzos, Gary A; Arce-Nazario, Javier A

2016-10-01

Urbanization affects the microbial loading into tropical streams, but its impact on water quality varies across watersheds. Rainfall in tropical environments also complicates microbial dynamics due to high seasonal and annual variations. Understanding the dynamics of fecal contamination in tropical surface waters may be further hindered by limitations from the utilization of traditional microbial indicators. We measured traditional (Enterococcus spp. and Escherichia coli), as well as alternate (enterophages and coliphages) indicators of fecal contamination in a tropical watershed in Puerto Rico during a 1-year period, and examined their relationship with rainfall events across an urbanization gradient. Enterococcus spp. and E. coli concentrations were 4 to 5 logs higher in non-urbanized or pristine sites when compared to enterophages and coliphages, suggesting that traditional fecal indicator bacteria may be natural inhabitants of pristine tropical waters. All of the tested indicators were positively correlated with rainfall and urbanization, except in the most urbanized sites, where rainfall may have had a dilution effect. The present study indicates that utilizing novel indicators of microbial water quality may improve the assessment of fecal contamination and pathogen risk for tropical watersheds.

Abundance and diversity of microbial inhabitants in European spacecraft-associated clean rooms.

PubMed

Stieglmeier, Michaela; Rettberg, Petra; Barczyk, Simon; Bohmeier, Maria; Pukall, Rüdiger; Wirth, Reinhard; Moissl-Eichinger, Christine

2012-06-01

The determination of the microbial load of a spacecraft en route to interesting extraterrestrial environments is mandatory and currently based on the culturable, heat-shock-surviving portion of microbial contaminants. Our study compared these classical bioburden measurements as required by NASA's and ESA's guidelines for the microbial examination of flight hardware, with molecular analysis methods (16S rRNA gene cloning and quantitative PCR) to further develop our understanding of the diversity and abundance of the microbial communities of spacecraft-associated clean rooms. Three samplings of the Herschel Space Observatory and its surrounding clean rooms were performed in two different European facilities. Molecular analyses detected a broad diversity of microbes typically found in the human microbiome with three bacterial genera (Staphylococcus, Propionibacterium, and Brevundimonas) common to all three locations. Bioburden measurements revealed a low, but heterogeneous, abundance of spore-forming and other heat-resistant microorganisms. Total cell numbers estimated by quantitative real-time PCR were typically 3 orders of magnitude greater than those determined by viable counts, which indicates a tendency for traditional methods to underestimate the extent of clean room bioburden. Furthermore, the molecular methods allowed the detection of a much broader diversity than traditional culture-based methods.

PubMed Central

El, Okki S. El Hadef; El Groud, R.; Kenana, H.; Quessy, S.

2005-01-01

The neck, shoulder, flank, and thigh of 36 bovine and 30 ovine carcasses were swabbed for bacteriological analyses. The greatest microbial load was found on the neck. The site averages for the flora analyzed indicated that the levels of contamination were greater than those in similar studies in France, Morocco, and Tunisia. PMID:16152721

Enhanced Lipid and Biodiesel Production from Glucose-Fed Activated Sludge: Kinetics an Microbial Community Analysis

EPA Science Inventory

An innovative approach to increase biofuel feedstock lipid yields from municipal sewage sludge via manipulation of carbon:nitrogen (C:N) ratio and glucose loading in activated sludge bioreactors was investigated. Sludge lipid and fatty acid methyl ester (biodiesel) yields (% cel...

Three-dimensional graphene nanosheets as cathode catalysts in standard and supercapacitive microbial fuel cell.

PubMed

Santoro, Carlo; Kodali, Mounika; Kabir, Sadia; Soavi, Francesca; Serov, Alexey; Atanassov, Plamen

2017-07-15

Three-dimensional graphene nanosheets (3D-GNS) were used as cathode catalysts for microbial fuel cells (MFCs) operating in neutral conditions. 3D-GNS catalysts showed high performance towards oxygen electroreduction in neutral media with high current densities and low hydrogen peroxide generation compared to activated carbon (AC). 3D-GNS was incorporated into air-breathing cathodes based on AC with three different loadings (2, 6 and 10 mgcm -2 ). Performances in MFCs showed that 3D-GNS had the highest performances with power densities of 2.059 ± 0.003 Wm -2 , 1.855 ± 0.007 Wm -2 and 1.503 ± 0.005 Wm -2 for loading of 10, 6 and 2 mgcm -2 respectively. Plain AC had the lowest performances (1.017 ± 0.009 Wm -2 ). The different cathodes were also investigated in supercapacitive MFCs (SC-MFCs). The addition of 3D-GNS decreased the ohmic losses by 14-25%. The decrease in ohmic losses allowed the SC-MFC with 3D-GNS (loading 10 mgcm -2 ) to have the maximum power (P max ) of 5.746 ± 0.186 Wm -2 . At 5 mA, the SC-MFC featured an "apparent" capacitive response that increased from 0.027 ± 0.007 F with AC to 0.213 ± 0.026 F with 3D-GNS (loading 2 mgcm -2 ) and further to 1.817 ± 0.040 F with 3D-GNS (loading 10 mgcm -2 ).

Nitrogen removal and microbial communities in a three-stage system simulating a riparian environment.

PubMed

Wang, Ziyuan; Wang, Zhixin; Pei, Yuansheng

2014-06-01

The riparian zone is an active interface for nitrogen removal, in which nitrogen transformations by microorganisms have not been valued. In this study, a three-stage system was constructed to simulate the riparian zone environments, and nitrogen removal as well as the microbial community was investigated in this 'engineered riparian system'. The results demonstrated that stage 1 of this system accounted for 41-51 % of total nitrogen removal. Initial ammonium loading and redox potential significantly impacted the nitrogen removal performances. Stages 1 and 2 were both composed of an anoxic/oxic (A/O) zone and an anaerobic column. The A/O zone removed most of the ammonium load (6.8 g/m(2)/day), while the anaerobic column showed a significant nitrate removal rate (11.1 g/m(2)/day). Molecular biological analysis demonstrated that bacterial diversity was high in the A/O zones, where ammonium-oxidizing bacteria and nitrite-oxidizing bacteria accounted for 8.42 and 3.32 % of the bacterial population, respectively. The denitrifying bacteria Acidovorax sp. and the nitrifying bacteria Nitrosospira/Nitrosomonas were the predominant microorganisms in this engineered riparian system. This three-stage system was established to achieve favorable nitrogen removal and the microbial community in the system was also retained. This investigation should deepen our understanding of biological nitrogen removal in engineered riparian zones.

A novel continuous two-phase partitioning bioreactor operated with polymeric tubing: Performance validation for enhanced biological removal of toxic substrates.

PubMed

Tomei, M Concetta; Mosca Angelucci, Domenica; Daugulis, Andrew J

2017-02-01

A continuous two-phase partitioning bioreactor (C-TPPB), operated with coiled tubing made of the DuPont polymer Hytrel 8206, was tested for the bioremediation of 4-chlorophenol, as a model toxic compound. The tubing was immersed in the aqueous phase, with the contaminated water flowing tube-side, and an adapted microbial culture suspended in the bioreactor itself, with the metabolic demand of the cells creating a concentration gradient to cause the substrate to diffuse into the bioreactor for biodegradation. The system was operated over a range of loadings (tubing influent concentration 750-1500 mg L -1 ), with near-complete substrate removal in all cases. Distribution of the contaminant at the end of the tests (96 h) highlighted biological removal in the range of 87-95%, while the amount retained in the polymer ranged from ∼1 to 8%. Mass transfer of the substrate across the tubing wall was not limiting, and the polymer demonstrated the capacity to buffer the substrate loadings and to adapt to microbial metabolism. The impact of C-TPPB operation on biomass activity was also investigated by a kinetic characterization of the microbial culture, which showed better resistance to substrate inhibition after C-TPPB operation, thereby confirming the beneficial effect of sub-inhibitory controlled conditions, characteristic of TPPB systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

Transport of Cryptosporidium, Giardia, Source-specific Indicator Organisms, and Standard Water Quality Constituents During Storm Events

NASA Astrophysics Data System (ADS)

Sturdevant-Rees, P. L.; Bourdeau, D.; Baker, R.; Long, S. C.; Barten, P. K.

2004-05-01

Microbial and water-quality measurements are collected during storm events under a variety of meteorological and land-use conditions in order to 1) identify risk of Cryptosporidium oocysts, Giardia cysts and other constituents, including microbial indicator organisms, entering surface waters from various land uses during periods of surface runoff; 2) optimize storm sampling procedures for these parameters; and 3) optimize strategies for accurate determination of constituent loads. The investigation is focused on four isolated land uses: forested with free ranging wildlife, beaver influenced forested with free ranging wildlife, residential/commercial, and dairy farm grazing/pastureland using an upstream and downstream sampling strategy. Traditional water-quality analyses include pH, temperature, turbidity, conductivity, total suspended solids, total phosphorus, total Kjeldahl-nitrogen, and ammonia nitrogen, Giardia cysts and Cryptosporidium oocysts. Total coliforms and fecal coliforms are measured as industry standard microbial analyses. Sorbitol-fermenting Bifidobacteria, Rhodococcus coprophilus, Clostridium perfringens spores, and Somatic and F-specific coliphages are measured at select sites as potential alternative source-specific indicator organisms. Upon completion of the project, the final database will consist of wet weather transport data for a set of parameters during twenty-four distinct storm-events in addition to monthly baseline data. A subset of the results to date will be presented, with focus placed on demonstrating the impact of beaver on constituent loadings over a variety of hydrologic and meteorological conditions.

Hydrogel-Based Fluorescent Dual pH and Oxygen Sensors Loaded in 96-Well Plates for High-Throughput Cell Metabolism Studies.

PubMed

Wu, Shanshan; Wu, Siying; Yi, Zheyuan; Zeng, Fei; Wu, Weizhen; Qiao, Yuan; Zhao, Xingzhong; Cheng, Xing; Tian, Yanqing

2018-02-13

In this study, we developed fluorescent dual pH and oxygen sensors loaded in multi-well plates for in-situ and high-throughput monitoring of oxygen respiration and extracellular acidification during microbial cell growth for understanding metabolism. Biocompatible PHEMA-co-PAM materials were used as the hydrogel matrix. A polymerizable oxygen probe (OS2) derived from PtTFPP and a polymerizable pH probe (S2) derived from fluorescein were chemically conjugated into the matrix to solve the problem of the probe leaching from the matrix. Gels were allowed to cure directly on the bottom of 96-well plates at room-temperature via redox polymerization. The influence of matrix's composition on the sensing behaviors was investigated to optimize hydrogels with enough robustness for repeatable use with good sensitivity. Responses of the dual sensing hydrogels to dissolved oxygen (DO) and pH were studied. These dual oxygen-pH sensing plates were successfully used for microbial cell-based screening assays, which are based on the measurement of fluorescence intensity changes induced by cellular oxygen consumption and pH changes during microbial growth. This method may provide a real-time monitoring of cellular respiration, acidification, and a rapid kinetic assessment of multiple samples for cell viability as well as high-throughput drug screening. All of these assays can be carried out by a conventional plate reader.

Impact of cold plasma on Citrobacter freundii in apple juice: inactivation kinetics and mechanisms.

PubMed

Surowsky, Björn; Fröhling, Antje; Gottschalk, Nathalie; Schlüter, Oliver; Knorr, Dietrich

2014-03-17

Various studies have shown that cold plasma is capable of inactivating microorganisms located on a variety of food surfaces, food packaging materials and process equipment under atmospheric pressure conditions; however, less attention has been paid to the impact of cold plasma on microorganisms in liquid foodstuffs. The present study investigates cold plasma's ability to inactivate Citrobacter freundii in apple juice. Optical emission spectroscopy (OES) and temperature measurements were performed to characterise the plasma source. The plasma-related impact on microbial loads was evaluated by traditional plate count methods, while morphological changes were determined using scanning electron microscopy (SEM). Physiological property changes were obtained through flow cytometric measurements (membrane integrity, esterase activity and membrane potential). In addition, mathematical modelling was performed in order to achieve a reliable prediction of microbial inactivation and to establish the basis for possible industrial implementation. C. freundii loads in apple juice were reduced by about 5 log cycles after a plasma exposure of 480s using argon and 0.1% oxygen plus a subsequent storage time of 24h. The results indicate that a direct contact between bacterial cells and plasma is not necessary for achieving successful inactivation. The plasma-generated compounds in the liquid, such as H2O2 and most likely hydroperoxy radicals, are particularly responsible for microbial inactivation. Copyright © 2014. Published by Elsevier B.V.

Microneedle arrays allow lower microbial penetration than hypodermic needles in vitro.

PubMed

Donnelly, Ryan F; Singh, Thakur Raghu Raj; Tunney, Michael M; Morrow, Desmond I J; McCarron, Paul A; O'Mahony, Conor; Woolfson, A David

2009-11-01

In this study we determined, for the first time, the ability of microorganisms to traverse microneedle-induced holes using two different in vitro models. When employing Silescol membranes, the numbers of Candida albicans, Pseudomonas aeruginosa and Staphylococcus epidermidis crossing the membranes were an order of magnitude lower when the membranes were punctured by microneedles rather than a 21G hypodermic needle. Apart from the movement of C. albicans across hypodermic needle-punctured membranes, where 40.2% of the microbial load on control membranes permeated the barrier over 24 h, the numbers of permeating microorganisms was less than 5% of the original microbial load on control membranes. Experiments employing excised porcine skin and radiolabelled microorganisms showed that the numbers of microorganisms penetrating skin beyond the stratum corneum were approximately an order of magnitude greater than the numbers crossing Silescol membranes in the corresponding experiments. Approximately 10(3) cfu of each microorganism adhered to hypodermic needles during insertion. The numbers of microorganisms adhering to MN arrays were an order of magnitude higher in each case. We have shown here that microneedle puncture resulted in significantly less microbial penetration than did hypodermic needle puncture and that no microorganisms crossed the viable epidermis in microneedle-punctured skin, in contrast to needle-punctured skin. Given the antimicrobial properties of skin, it is, therefore, likely that application of microneedle arrays to skin in an appropriate manner would not cause either local or systemic infection in normal circumstances in immune-competent patients. In supporting widespread clinical use of microneedle-based delivery systems, appropriate animal studies are now needed to conclusively demonstrate this in vivo. Safety in patients will be enhanced by aseptic or sterile manufacture and by fabricating microneedles from self-disabling materials (e.g. dissolving or biodegradable polymers) to prevent inappropriate or accidental reuse.

The close relation between Lactococcus and Methanosaeta is a keystone for stable methane production from molasses wastewater in a UASB reactor.

PubMed

Kim, Tae Gwan; Yun, Jeonghee; Cho, Kyung-Suk

2015-10-01

The up-flow anaerobic sludge blanket (UASB) reactor is a promising method for the treatment of high-strength industrial wastewaters due to advantage of its high treatment capacity and settleable suspended biomass retention. Molasses wastewater as a sugar-rich waste is one of the most valuable raw material for bioenergy production due to its high organic strength and bioavailability. Interpretation for complex interactions of microbial community structures and operational parameters can help to establish stable biogas production. RNA-based approach for biogas production systems is recommended for analysis of functionally active community members which are significantly underestimated. In this study, methane production and active microbial community were characterized in an UASB reactor using molasses wastewater as feedstock. The UASB reactor achieved a stable process performance at an organic loading rate of 1.7~13.8-g chemical oxygen demand (COD,·L(-1) day(-1); 87-95 % COD removal efficiencies), and the maximum methane production rate was 4.01 L-CH4·at 13.8 g-COD L(-1) day(-1). Lactococcus and Methanosaeta were comprised up to 84 and 80 % of the active bacterial and archaeal communities, respectively. Network analysis of reactor performance and microbial community revealed that Lactococcus and Methanosaeta were network hub nodes and positively correlated each other. In addition, they were positively correlated with methane production and organic loading rate, and they shared the other microbial hub nodes as neighbors. The results indicate that the close association between Lactococcus and Methanosaeta is responsible for the stable production of methane in the UASB reactor using molasses wastewater.

Short reads from honey bee (Apis sp.) sequencing projects reflect microbial associate diversity

PubMed Central

Hurst, Gregory D.D.

2017-01-01

High throughput (or ‘next generation’) sequencing has transformed most areas of biological research and is now a standard method that underpins empirical study of organismal biology, and (through comparison of genomes), reveals patterns of evolution. For projects focused on animals, these sequencing methods do not discriminate between the primary target of sequencing (the animal genome) and ‘contaminating’ material, such as associated microbes. A common first step is to filter out these contaminants to allow better assembly of the animal genome or transcriptome. Here, we aimed to assess if these ‘contaminations’ provide information with regard to biologically important microorganisms associated with the individual. To achieve this, we examined whether the short read data from Apis retrieved elements of its well established microbiome. To this end, we screened almost 1,000 short read libraries of honey bee (Apis sp.) DNA sequencing project for the presence of microbial sequences, and find sequences from known honey bee microbial associates in at least 11% of them. Further to this, we screened ∼500 Apis RNA sequencing libraries for evidence of viral infections, which were found to be present in about half of them. We then used the data to reconstruct draft genomes of three Apis associated bacteria, as well as several viral strains de novo. We conclude that ‘contamination’ in short read sequencing libraries can provide useful genomic information on microbial taxa known to be associated with the target organisms, and may even lead to the discovery of novel associations. Finally, we demonstrate that RNAseq samples from experiments commonly carry uneven viral loads across libraries. We note variation in viral presence and load may be a confounding feature of differential gene expression analyses, and as such it should be incorporated as a random factor in analyses. PMID:28717593

Reduction of microbial contamination and improvement of germination of sweet basil (Ocimum basilicum L.) seeds via surface dielectric barrier discharge

NASA Astrophysics Data System (ADS)

Ambrico, Paolo F.; Šimek, Milan; Morano, Massimo; De Miccolis Angelini, Rita M.; Minafra, Angelantonio; Trotti, Pasquale; Ambrico, Marianna; Prukner, Václav; Faretra, Francesco

2017-08-01

Naturally contaminated basil seeds were treated by a surface dielectric barrier discharge driven in the humid air by an amplitude modulated AC high voltage to avoid heat shock. In order to avoid direct contact of seeds with microdischarge filaments, the seeds to be treated were placed at sufficient distance from the surface discharge. After treatment, the seeds were analyzed in comparison with control samples for their microbial contamination as well as for the capability of germination and seedling growth. Moreover, chemical modification of seed surface was observed through the elemental energy dispersive x-ray analysis and wettability tests. We found that treatment applied at 20% duty cycle (effective discharge duration up to 20 s) significantly decreases microbial load without reducing the viability of the seeds. On the other side, seedling growth was considerably accelerated after the treatment, and biometric growth parameters of seedlings (total length, weight, leaf extension) considerably increased compared to the controls. Interestingly, scanning electron microscopy images taken for the different duration of treatment revealed that seed radicle micropylar regions underwent significant morphological changes while the coat was substantially undamaged. Inside the seed, the embryo seemed to be well preserved while the endosperm body was detached from the epithelial tegument. A total of 9 different genera of fungi were recovered from the analyzed seeds. Scanning electron microscopy images revealed that conidia were localized especially in the micropylar region, and after plasma treatment, most of them showed substantial damages. Therefore, the overall effect of the treatment of naturally contaminated seeds by reactive oxygen and nitrogen species produced by plasma and the consequent changes in surface chemistry and microbial load can significantly improve seed vigor.

Short reads from honey bee (Apis sp.) sequencing projects reflect microbial associate diversity.

PubMed

Gerth, Michael; Hurst, Gregory D D

2017-01-01

High throughput (or 'next generation') sequencing has transformed most areas of biological research and is now a standard method that underpins empirical study of organismal biology, and (through comparison of genomes), reveals patterns of evolution. For projects focused on animals, these sequencing methods do not discriminate between the primary target of sequencing (the animal genome) and 'contaminating' material, such as associated microbes. A common first step is to filter out these contaminants to allow better assembly of the animal genome or transcriptome. Here, we aimed to assess if these 'contaminations' provide information with regard to biologically important microorganisms associated with the individual. To achieve this, we examined whether the short read data from Apis retrieved elements of its well established microbiome. To this end, we screened almost 1,000 short read libraries of honey bee ( Apis sp.) DNA sequencing project for the presence of microbial sequences, and find sequences from known honey bee microbial associates in at least 11% of them. Further to this, we screened ∼500 Apis RNA sequencing libraries for evidence of viral infections, which were found to be present in about half of them. We then used the data to reconstruct draft genomes of three Apis associated bacteria, as well as several viral strains de novo . We conclude that 'contamination' in short read sequencing libraries can provide useful genomic information on microbial taxa known to be associated with the target organisms, and may even lead to the discovery of novel associations. Finally, we demonstrate that RNAseq samples from experiments commonly carry uneven viral loads across libraries. We note variation in viral presence and load may be a confounding feature of differential gene expression analyses, and as such it should be incorporated as a random factor in analyses.

Comparison of keypads and touch-screen mobile phones/devices as potential risk for microbial contamination.

PubMed

Koroglu, Mehmet; Gunal, Selami; Yildiz, Fatma; Savas, Mehtap; Ozer, Ali; Altindis, Mustafa

2015-12-30

Touch-screen mobile phones/devices (TMPs/Ds) are increasingly used in hospitals. They may act as a mobile reservoir for microbial pathogens. The rates of microbial contamination of TMPs/Ds and keypad mobile phones (KMPs) with respect to different variables including use by healthcare workers (HCWs)/non-HCWs and the demographic characteristics of users were investigated. A total of 205 mobile phones/devices were screened for microbial contamination: 76 devices belonged to HCWs and 129 devices belonged to the non-HCW group. By rubbing swabs to front screen, back, keypad, and metallic surfaces of devices, 444 samples were collected. Of 205 mobile phones/devices, 143 (97.9%) of the TMPs/Ds and 58 (98.3%) of the KMPs were positive for microbial contamination, and there were no significant differences in contamination rates between these groups, although TMPs/Ds had significantly higher microbial load than KMPs (p <0.05). The significant difference in this analysis was attributable to the screen size of mobile phones ≥ 5". Microbial contamination rates increased significantly as phone size increased (p <0.05). Higher numbers of coagulase-negative Staphylococci (CNS) were isolated from KMPs than TMPs/Ds (p = 0.049). The incidence of Enterococcus spp. was higher on the KMPs of HCWs, and methicillin resistant CNS was higher from the TMPs/Ds of non-HCWs (p <0.05). Isolation of CNS, Streptococcus spp. and Escherichia coli was higher from the TMPs/Ds of HCWs (p <0.05). We found no significant difference between TMP/Ds and KMPs in terms of microbial contamination, but TMP/Ds harboured more colonies and total microbial counts increased with screen size.

Exploring the Impacts of Anthropogenic Disturbance on Seawater and Sediment Microbial Communities in Korean Coastal Waters Using Metagenomics Analysis

PubMed Central

Won, Nam-Il; Kim, Ki-Hwan; Kang, Ji Hyoun; Park, Sang Rul; Lee, Hyuk Je

2017-01-01

The coastal ecosystems are considered as one of the most dynamic and vulnerable environments under various anthropogenic developments and the effects of climate change. Variations in the composition and diversity of microbial communities may be a good indicator for determining whether the marine ecosystems are affected by complex forcing stressors. DNA sequence-based metagenomics has recently emerged as a promising tool for analyzing the structure and diversity of microbial communities based on environmental DNA (eDNA). However, few studies have so far been performed using this approach to assess the impacts of human activities on the microbial communities in marine systems. In this study, using metagenomic DNA sequencing (16S ribosomal RNA gene), we analyzed and compared seawater and sediment communities between sand mining and control (natural) sites in southern coastal waters of Korea to assess whether anthropogenic activities have significantly affected the microbial communities. The sand mining sites harbored considerably lower levels of microbial diversities in the surface seawater community during spring compared with control sites. Moreover, the sand mining areas had distinct microbial taxonomic group compositions, particularly during spring season. The microbial groups detected solely in the sediment load/dredging areas (e.g., Marinobacter, Alcanivorax, Novosphingobium) are known to be involved in degradation of toxic chemicals such as hydrocarbon, oil, and aromatic compounds, and they also contain potential pathogens. This study highlights the versatility of metagenomics in monitoring and diagnosing the impacts of human disturbance on the environmental health of marine ecosystems from eDNA. PMID:28134828

Olive Ridley Sea Turtle Hatching Success as a Function of the Microbial Abundance in Nest Sand at Ostional, Costa Rica

PubMed Central

Bézy, Vanessa S.; Valverde, Roldán A.; Plante, Craig J.

2015-01-01

Several studies have suggested that significant embryo mortality is caused by microbes, while high microbial loads are generated by the decomposition of eggs broken by later nesting turtles. This occurs commonly when nesting density is high, especially during mass nesting events (arribadas). However, no previous research has directly quantified microbial abundance and the associated effects on sea turtle hatching success at a nesting beach. The aim of this study was to test the hypothesis that the microbial abundance in olive ridley sea turtle nest sand affects the hatching success at Ostional, Costa Rica. We applied experimental treatments to alter the microbial abundance within the sand into which nests were relocated. We monitored temperature, oxygen, and organic matter content throughout the incubation period and quantified the microbial abundance within the nest sand using a quantitative polymerase chain reaction (qPCR) molecular analysis. The most successful treatment in increasing hatching success was the removal and replacement of nest sand. We found a negative correlation between hatching success and fungal abundance (fungal 18S rRNA gene copies g-1 nest sand). Of secondary importance in determining hatching success was the abundance of bacteria (bacterial 16S rRNA gene copies g-1 g-1 nest sand). Our data are consistent with the hypothesis that high microbial activity is responsible for the lower hatching success observed at Ostional beach. Furthermore, the underlying mechanism appears to be the deprivation of oxygen and exposure to higher temperatures resulting from microbial decomposition in the nest. PMID:25714355

Exploring the Impacts of Anthropogenic Disturbance on Seawater and Sediment Microbial Communities in Korean Coastal Waters Using Metagenomics Analysis.

PubMed

Won, Nam-Il; Kim, Ki-Hwan; Kang, Ji Hyoun; Park, Sang Rul; Lee, Hyuk Je

2017-01-27

The coastal ecosystems are considered as one of the most dynamic and vulnerable environments under various anthropogenic developments and the effects of climate change. Variations in the composition and diversity of microbial communities may be a good indicator for determining whether the marine ecosystems are affected by complex forcing stressors. DNA sequence-based metagenomics has recently emerged as a promising tool for analyzing the structure and diversity of microbial communities based on environmental DNA (eDNA). However, few studies have so far been performed using this approach to assess the impacts of human activities on the microbial communities in marine systems. In this study, using metagenomic DNA sequencing (16S ribosomal RNA gene), we analyzed and compared seawater and sediment communities between sand mining and control (natural) sites in southern coastal waters of Korea to assess whether anthropogenic activities have significantly affected the microbial communities. The sand mining sites harbored considerably lower levels of microbial diversities in the surface seawater community during spring compared with control sites. Moreover, the sand mining areas had distinct microbial taxonomic group compositions, particularly during spring season. The microbial groups detected solely in the sediment load/dredging areas (e.g., Marinobacter, Alcanivorax, Novosphingobium) are known to be involved in degradation of toxic chemicals such as hydrocarbon, oil, and aromatic compounds, and they also contain potential pathogens. This study highlights the versatility of metagenomics in monitoring and diagnosing the impacts of human disturbance on the environmental health of marine ecosystems from eDNA.

Microbial load monitor

NASA Technical Reports Server (NTRS)

Holen, J. T.; Royer, E. R.

1976-01-01

A card configuration which combines the functions of identification, enumeration and antibiotic sensitivity into one card was developed. An instrument package was designed around the card to integrate the card filling, incubation reading, computation and decision making process into one compact unit. Support equipment was also designed to prepare the expandable material used in the MLM.

Using the Q10 model to simulate E. coli survival in cowpats on grazing lands

EPA Science Inventory

Microbiological quality of surface waters can be affected by microbial load in runoff from grazing lands. This effect, with other factors, depends on the survival of microorganisms in animal waste deposited on pastures. Since temperature is a leading environmental parameter affec...

Nitrous oxide emission from denitrification in stream and river networks

Treesearch

J.J. Beaulieu; J.L. Tank; S.K. Hamilton; W.M. Wollheim; R.O. Hall; P.J. Mulholland; B.J. Peterson; L.R. Ashkenas; L.W. Cooper; C.N. Dahm; W.K. Dodds; N.B. Grimm; S.L. Johnson; W.H. McDowell; G.C. Poole; H.M. Valett; C.P. Arango; M.J. Bernot; A.J. Burgin; C.L. Crenshaw; A.M. Helton; L.T. Johnson; J.M. O' Brien; J.D. Potter; R.W. Sheibley; D.J. Sobota; S.M. Thomas

2011-01-01

Nitrous oxide (N20) is a potent greenhouse gas that contributes to climate change and stratospheric ozone destruction. Anthropogenic nitrogen (N) loading to river networks is a potentially important source of N20 via microbial denitrification that converts N to N20 and dinitrogen (N2...

Nitrous oxide emission from denitrification in stream and river networks

EPA Science Inventory

Nitrous oxide (N2O) is a potent greenhouse gas that contributes to climate change and stratospheric ozone destruction. Anthropogenic nitrogen (N) loading to river networks is a potentially important source of N2O via microbial denitrification which converts N to N2O and dinitrog...

Impacts of land management practices on stream microbial loading in Northeast GA

EPA Science Inventory

Identification of dominant source(s) of fecal pollution in a watershed is necessary for assessing the safety of recreational water and for protecting water resources. The objective of this study was to examine the relative abundance of molecular fecal markers from two cattle farm...

Facultative Lagoons. Student Manual. Biological Treatment Process Control.

ERIC Educational Resources Information Center

Andersen, Lorri

The textual material for a unit on facultative lagoons is presented in this student manual. Topic areas discussed include: (1) loading; (2) microbial theory; (3) structure and design; (4) process control; (5) lagoon start-up; (6) data handling and analysis; (7) lagoon maintenance (considering visual observations, pond structure, safety, odor,…

Shelf life of ready to use peeled shrimps as affected by thymol essential oil and modified atmosphere packaging.

PubMed

Mastromatteo, Marianna; Danza, Alessandra; Conte, Amalia; Muratore, Giuseppe; Del Nobile, Matteo Alessandro

2010-12-15

In this work the influence of different packaging strategies on the shelf life of ready to use peeled shrimps was investigated. First, the effectiveness of the coating (Coat) and the active coating loaded with different concentrations of thymol (Coat-500, Coat-1000, and Coat-1500) on the quality loss of the investigated food product packaged in air was addressed; afterwards, the thymol concentration that had shown the best performance was used in combination with MAP (5% O(2); 95% CO(2)). Microbial cell load of main spoilage microorganisms, pH and sensorial quality were monitored during the refrigerated storage. Results of the first step suggested that the sole coating did not affect the microbial growth. A slight antimicrobial effect was obtained when the coating was loaded with thymol and a concentration dependence was also observed. Moreover, the active coating was effective in minimizing the sensory quality loss of the investigated product, it was particularly true at the lowest thymol concentration. In the second step, the thymol concentration (1000 ppm) that showed the strike balance between microbial and sensorial quality was chosen in combination with MAP. As expected, MAP significantly affected the growth of the mesophilic bacteria. In particular, a cell load reduction of about 2 log cycle for the samples under MAP respect to that in air was obtained. Moreover, the MAP packaging inhibited the growth of the Pseudomonas spp. and hydrogen sulphide-producing bacteria. The MAP alone was not able to improve the shelf life of the uncoated samples. In fact, no significant difference between the control samples packaged in air and MAP was observed. Whilst, the use of coating under MAP condition prolonged the shelf life of about 6 days with respect to the same samples packaged in air. Moreover, when the MAP was used in combination with thymol, a further shelf life prolongation with respect to the samples packaged in air was observed. In particular, a shelf life of about 14 days for the active coating under MAP compared to the same samples in air (5 days) was obtained. Copyright © 2010 Elsevier B.V. All rights reserved.

Possible association between celiac disease and bacterial transglutaminase in food processing: a hypothesis.

PubMed

Lerner, Aaron; Matthias, Torsten

2015-08-01

The incidence of celiac disease is increasing worldwide, and human tissue transglutaminase has long been considered the autoantigen of celiac disease. Concomitantly, the food industry has introduced ingredients such as microbial transglutaminase, which acts as a food glue, thereby revolutionizing food qualities. Several observations have led to the hypothesis that microbial transglutaminase is a new environmental enhancer of celiac disease. First, microbial transglutaminase deamidates/transamidates glutens such as the endogenous human tissue transglutaminase. It is capable of crosslinking proteins and other macromolecules, thereby changing their antigenicity and resulting in an increased antigenic load presented to the immune system. Second, it increases the stability of protein against proteinases, thus diminishing foreign protein elimination. Infections and the crosslinked nutritional constituent gluten and microbial transglutaminase increase the permeability of the intestine, where microbial transglutaminases are necessary for bacterial survival. The resulting intestinal leakage allows more immunogenic foreign molecules to induce celiac disease. The increased use of microbial transglutaminase in food processing may promote celiac pathogenesis ex vivo, where deamidation/transamidation starts, possibly explaining the surge in incidence of celiac disease. If future research substantiates this hypothesis, the findings will affect food product labeling, food additive policies of the food industry, and consumer health education. © The Author(s) 2015. Published by Oxford University Press on behalf of the International Life Sciences Institute.

Non-breast milk feeding in developing countries: challenge from microbial and chemical contaminants.

PubMed

Weisstaub, Gerardo; Uauy, Ricardo

2012-01-01

Complementary foods based on cow's milk or gruels consumed by children in developing countries are often contaminated by bacteria during preparation, and ambient temperature rapidly increases microbial load. Thus infant formula or other weaning foods may cause diarrhea in young infants accounting for 25-33% of all deaths <5 years globally. Environmental chemicals such as metals (As, Pb, Cu) and nitrates can cause vomiting/diarrhea. Polychlorinated biphenyls derived from plastics, present in formula and/or breast milk, are endocrine disruptors (the potential threats are not fully quantifiable). The prevailing view is that benefits from breastfeeding outweigh potential risks. Copyright © 2012 S. Karger AG, Basel.

Monitoring biodiversity in libraries: a pilot study and perspectives for indoor air quality.

PubMed

Valeriani, F; Cianfanelli, C; Gianfranceschi, G; Santucci, S; Romano Spica, V; Mucci, N

2017-09-01

Indoor Air Quality (IAQ) in libraries is influenced by the presence of specific factors which can impact on both paper storage as well as people health. Microclimatic conditions induce and support a biodiversity pattern involving environmental and anthropic microorganisms. We used a multidisciplinary monitoring model to characterize microflora biodiversity by Next Generation Sequencing (NGS). Biodiversity indexes were adapted to evaluate anthropic vs environmental pollution by combining Shannon mean index (H), species representativeness (E H ), human/environmental pollution ratio (SA) to better characterize the NGS output and acquire synthetic information on Indoor Air Microbial Biodiversity (IAMB). Results indicate a frequently low microbial load (IGCM/m 3 < 1000) characterized by different species (n = 102), including several cellulose metabolizing bacteria. Workers and visitors appeared a relevant source of microbial contamination. Air biodiversity assayed by NGS seems a promising marker for studying IAQ.

Microbial and chemical contamination during and after flooding in the Ohio River-Kentucky, 2011.

PubMed

Yard, Ellen E; Murphy, Matthew W; Schneeberger, Chandra; Narayanan, Jothikumar; Hoo, Elizabeth; Freiman, Alexander; Lewis, Lauren S; Hill, Vincent R

2014-09-19

Surface water contaminants in Kentucky during and after 2011 flooding were characterized. Surface water samples were collected during flood stage (May 2-4, 2011; n = 15) and after (July 25-26, 2011; n = 8) from four different cities along the Ohio River and were analyzed for the presence of microbial indicators, pathogens, metals, and chemical contaminants. Contaminant concentrations during and after flooding were compared using linear and logistic regression. Surface water samples collected during flooding had higher levels of E. coli, enterococci, Salmonella, Campylobacter, E. coli O157:H7, adenovirus, arsenic, copper, iron, lead, and zinc compared to surface water samples collected 3-months post-flood (P < 0.05). These results suggest that flooding increases microbial and chemical loads in surface water. These findings reinforce commonly recommended guidelines to limit exposure to flood water and to appropriately sanitize contaminated surfaces and drinking wells after contamination by flood water.

Microbial and chemical contamination during and after flooding in the Ohio River—Kentucky, 2011

PubMed Central

Yard, Ellen E.; Murphy, Matthew W.; Schneeberger, Chandra; Narayanan, Jothikumar; Hoo, Elizabeth; Freiman, Alexander; Lewis, Lauren S.; Hill, Vincent R.

2017-01-01

Surface water contaminants in Kentucky during and after 2011 flooding were characterized. Surface water samples were collected during flood stage (May 2–4, 2011; n = 15) and after (July 25–26, 2011; n = 8) from four different cities along the Ohio River and were analyzed for the presence of microbial indicators, pathogens, metals, and chemical contaminants. Contaminant concentrations during and after flooding were compared using linear and logistic regression. Surface water samples collected during flooding had higher levels of E. coli, enterococci, Salmonella, Campylobacter, E. coli O157:H7, adenovirus, arsenic, copper, iron, lead, and zinc compared to surface water samples collected 3-months post-flood (P < 0.05). These results suggest that flooding increases microbial and chemical loads in surface water. These findings reinforce commonly recommended guidelines to limit exposure to flood water and to appropriately sanitize contaminated surfaces and drinking wells after contamination by flood water. PMID:24967556

Organic content influences sediment microbial fuel cell performance and community structure.

PubMed

Zhao, Qing; Li, Ruying; Ji, Min; Ren, Zhiyong Jason

2016-11-01

This study constructed sediment microbial fuel cells (SMFCs) with different organic loadings without the amendment of external substrates, and it investigated how such variation affects electricity generation and microbial community structure. Results found sediment characteristics significantly influenced SMFC performance and appropriate organic content is important to maintain stable power outputs. SMFCs with loss of ignition (LOI) of 5% showed the most reliable performance in this study, while high organic content (LOI 10-16%) led to higher but very unstable voltage output because of biogas accumulation and worm activities. SMFCs with low organic content (1-3%) showed low power output. Different bacterial communities were found in SMFCs shown various power generation performance even those with similar organic contents. Thermodesulfovibrionaceae was found closely related to the system startup and Desulfobulbaceae showed great abundance in SMFCs with high power production. Copyright © 2016 Elsevier Ltd. All rights reserved.

Thin-layer heap bioleaching of copper flotation tailings containing high levels of fine grains and microbial community succession analysis

NASA Astrophysics Data System (ADS)

Hao, Xiao-dong; Liang, Yi-li; Yin, Hua-qun; Liu, Hong-wei; Zeng, Wei-min; Liu, Xue-duan

2017-04-01

Thin-layer heap bioleaching of copper flotation tailings containing high levels of fine grains was carried out by mixed cultures on a small scale over a period of 210 d. Lump ores as a framework were loaded at the bottom of the ore heap. The overall copper leaching rates of tailings and lump ores were 57.10wt% and 65.52wt%, respectively. The dynamic shifts of microbial community structures about attached microorganisms were determined using the Illumina MiSeq sequencing platform based on 16S rRNA amplification strategy. The results indicated that chemolithotrophic genera Acidithiobacillus and Leptospirillum were always detected and dominated the microbial community in the initial and middle stages of the heap bioleaching process; both genera might be responsible for improving the copper extraction. However, Thermogymnomonas and Ferroplasma increased gradually in the final stage. Moreover, the effects of various physicochemical parameters and microbial community shifts on the leaching efficiency were further investigated and these associations provided some important clues for facilitating the effective application of bioleaching.

Microbial burden prediction model for unmanned planetary spacecraft

NASA Technical Reports Server (NTRS)

Hoffman, A. R.; Winterburn, D. A.

1972-01-01

The technical development of a computer program for predicting microbial burden on unmanned planetary spacecraft is outlined. The discussion includes the derivation of the basic analytical equations, the selection of a method for handling several random variables, the macrologic of the computer programs and the validation and verification of the model. The prediction model was developed to (1) supplement the biological assays of a spacecraft by simulating the microbial accretion during periods when assays are not taken; (2) minimize the necessity for a large number of microbiological assays; and (3) predict the microbial loading on a lander immediately prior to sterilization and other non-lander equipment prior to launch. It is shown that these purposes not only were achieved but also that the prediction results compare favorably to the estimates derived from the direct assays. The computer program can be applied not only as a prediction instrument but also as a management and control tool. The basic logic of the model is shown to have possible applicability to other sequential flow processes, such as food processing.

A unique in vivo approach for investigating antimicrobial materials utilizing fistulated animals

NASA Astrophysics Data System (ADS)

Berean, Kyle J.; Adetutu, Eric M.; Zhen Ou, Jian; Nour, Majid; Nguyen, Emily P.; Paull, David; McLeod, Jess; Ramanathan, Rajesh; Bansal, Vipul; Latham, Kay; Bishop-Hurley, Greg J.; McSweeney, Chris; Ball, Andrew S.; Kalantar-Zadeh, Kourosh

2015-06-01

Unique in vivo tests were conducted through the use of a fistulated ruminant, providing an ideal environment with a diverse and vibrant microbial community. Utilizing such a procedure can be especially invaluable for investigating the performance of antimicrobial materials related to human and animal related infections. In this pilot study, it is shown that the rumen of a fistulated animal provides an excellent live laboratory for assessing the properties of antimicrobial materials. We investigate microbial colonization onto model nanocomposites based on silver (Ag) nanoparticles at different concentrations into polydimethylsiloxane (PDMS). With implantable devices posing a major risk for hospital-acquired infections, the present study provides a viable solution to understand microbial colonization with the potential to reduce the incidence of infection through the introduction of Ag nanoparticles at the optimum concentrations. In vitro measurements were also conducted to show the validity of the approach. An optimal loading of 0.25 wt% Ag is found to show the greatest antimicrobial activity and observed through the in vivo tests to reduce the microbial diversity colonizing the surface.

Metagenomic analysis of the soil microbial N-cycling community in response to increased N deposition in the alpine PNW

NASA Astrophysics Data System (ADS)

Simpson, A.; Zabowski, D.

2016-12-01

The effects of nitrogen (N) deposition, caused by increasing agricultural activity and increased fossil fuel usage in populated areas, is of great concern to managers of formerly pristine, N-limited environments such as the alpine. Increasingly available mineral N can cause changes in the soil microbial community, including downshifting naturally N-fixing microbial populations, and increasing nitrification (and soil acidification) with concomitant increases in nitrous oxide release. As part of a larger study to determine critical N loads for PNW alpine ecosystems, we used inorganic N fertilization to mimic increasing levels of N deposition at alpine sites at Mount Rainier, North Cascades, and Olympic National Parks. After 3 years of N application, we isolated DNA from soil samples taken from the rooting zones of two different species categories - lupine spp. and heather (evergreen shrub) spp. Amplicon-based libraries for genes for nitrogenase and ammonia monooxygenase were sequenced for each level of fertilization. We will present changes in diversity and size of the N-fixing and nitrifying microbial communities by increasing N application, site, and plant community.

Iron oxide nanoparticles in modern microbiology and biotechnology.

PubMed

Dinali, Ranmadugala; Ebrahiminezhad, Alireza; Manley-Harris, Merilyn; Ghasemi, Younes; Berenjian, Aydin

2017-08-01

Iron oxide nanoparticles (IONs) are one of the most developed and used nanomaterials in biotechnology and microbiology. These particles have unique physicochemical properties, which make them unique among nanomaterials. Therefore, many experiments have been conducted to develop facile synthesis methods for these particles and to make them biocompatible. Various effects of IONs on microorganisms have been reported. Depending on the microbial strain and nanoparticle (NP) concentration, IONs can stimulate or inhibit microbial growth. Due to the superparamagnetic properties of IONs, these NPs have used as nano sources of heat for hyperthermia in infected tissues. Antibiotic-loaded IONs are used for targeted delivery of chemical therapy direct to the infected organ and IONs have been used as a dirigible carrier for more potent antimicrobial nanomaterials such as silver nanoparticles. Magnetic NPs have been used for specific separation of pathogen and non-pathogen bacterial strains. Very recently, IONs were used as a novel tool for magnetic immobilization of microbial cells and process intensification in a biotechnological process. This review provides an overview of application of IONs in different microbial processes. Recommendations are also given for areas of future research.

The mechanisms of granulation of activated sludge in wastewater treatment, its optimization, and impact on effluent quality.

PubMed

Wilén, Britt-Marie; Liébana, Raquel; Persson, Frank; Modin, Oskar; Hermansson, Malte

2018-06-01

Granular activated sludge has gained increasing interest due to its potential in treating wastewater in a compact and efficient way. It is well-established that activated sludge can form granules under certain environmental conditions such as batch-wise operation with feast-famine feeding, high hydrodynamic shear forces, and short settling time which select for dense microbial aggregates. Aerobic granules with stable structure and functionality have been obtained with a range of different wastewaters seeded with different sources of sludge at different operational conditions, but the microbial communities developed differed substantially. In spite of this, granule instability occurs. In this review, the available literature on the mechanisms involved in granulation and how it affects the effluent quality is assessed with special attention given to the microbial interactions involved. To be able to optimize the process further, more knowledge is needed regarding the influence of microbial communities and their metabolism on granule stability and functionality. Studies performed at conditions similar to full-scale such as fluctuation in organic loading rate, hydrodynamic conditions, temperature, incoming particles, and feed water microorganisms need further investigations.

Insight into the role of facultative bacteria stimulated by micro-aeration in continuous bioreactors converting LCFA to methane.

PubMed

Duarte, Maria Salomé; Silva, Sérgio A; Salvador, Andreia F; Cavaleiro, Ana Júlia; Stams, Alfons J M; Alves, Maria Madalena; Pereira, Maria Alcina

2018-05-15

Conversion of unsaturated long chain fatty acids (LCFA) to methane in continuous bioreactors is not fully understood. Palmitate (C16:0) often accumulates during oleate (C18:1) biodegradation in methanogenic bioreactors, and the reason why this happens and which microorganisms catalyze this reaction remains unknown. Facultative anaerobic bacteria are frequently found in continuous reactors operated at high LCFA loads, but their function is unclear. To get more insight on the role of these bacteria, LCFA conversion was studied under microaerophilic conditions. For that, we compared bioreactors treating oleate-based wastewater (organic loading rates of 1 and 3 kg COD m-3 d-1), operated under different redox conditions (strictly anaerobic-AnR, -350 mV; microaerophilic-MaR, -250 mV). At the higher load, palmitate accumulated 7 times more in the MaR, where facultative anaerobes were more abundant, and only the biomass from this reactor could recover the methanogenic activity after a transient inhibition. In a second experiment, the abundance of facultative anaerobic bacteria, particularly Pseudomonas spp. (from which two strains were isolated), was strongly correlated (p<0.05) with palmitate-to-total LCFA percentage in the biofilm formed in a continuous plug flow reactor fed with very high loads of oleate. This work strongly suggests that micro-aeration stimulates the development of facultative bacteria that are critical for achieving LCFA conversion to methane in continuous bioreactors. Microbial networks and interactions of facultative and strict anaerobes in microbial communities should be considered in future studies.

The impact of point source pollution on shallow groundwater used for human consumption in a threshold country.

PubMed

Cruz, Mercedes Cecilia; Cacciabue, Dolores Gutiérrez; Gil, José F; Gamboni, Oscar; Vicente, María Soledad; Wuertz, Stefan; Gonzo, Elio; Rajal, Verónica B

2012-09-01

Many developing and threshold countries rely on shallow groundwater wells for their water supply whilst pit latrines are used for sanitation. We employed a unified strategy involving satellite images and environmental monitoring of 16 physico-chemical and microbiological water quality parameters to identify significant land uses that can lead to unacceptable deterioration of source water, in a region with a subtropical climate and seasonally restricted torrential rainfall in Northern Argentina. Agricultural and non-agricultural sources of nitrate were illustrated in satellite images and used to assess the organic load discharged. The estimated human organic load per year was 28.5 BOD(5) tons and the N load was 7.5 tons, while for poultry farms it was 9940-BOD(5) tons and 1037-N tons, respectively. Concentrations of nitrates and organics were significantly different between seasons in well water (p values of 0.026 and 0.039, respectively). The onset of the wet season had an extraordinarily negative impact on well water due in part to the high permeability of soils made up of fine gravels and coarse sand. Discriminant analysis showed that land uses had a pronounced seasonal influence on nitrates and introduced additional microbial contamination, causing nitrification and denitrification in shallow groundwater. P-well was highly impacted by a poultry farm while S-well was affected by anthropogenic pollution and background load, as revealed by Principal Component Analysis. The application of microbial source tracking techniques is recommended to corroborate local sources of human versus animal origin.

Impact of Roadway Stormwater Runoff on Microbial Contamination in the Receiving Stream.

PubMed

Wyckoff, Kristen N; Chen, Si; Steinman, Andrew J; He, Qiang

2017-09-01

Stormwater runoff from roadways has increasingly become a regulatory concern for water pollution control. Recent work has suggested roadway stormwater runoff as a potential source of microbial pollutants. The objective of this study was to determine the impact of roadway runoff on the microbiological quality of receiving streams. Microbiological quality of roadway stormwater runoff and the receiving stream was monitored during storm events with both cultivation-dependent fecal bacteria enumeration and cultivation-independent high-throughput sequencing techniques. Enumeration of total coliforms as a measure of fecal microbial pollution found consistently lower total coliform counts in roadway runoff than those in the stream water, suggesting that roadway runoff was not a major contributor of microbial pollutants to the receiving stream. Further characterization of the microbial community in the stormwater samples by 16S ribosomal RNA gene-based high-throughput amplicon sequencing revealed significant differences in the microbial composition of stormwater runoff from the roadways and the receiving stream. The differences in microbial composition between the roadway runoff and stream water demonstrate that roadway runoff did not appear to have a major influence on the stream in terms of microbiological quality. Thus, results from both fecal bacteria enumeration and high-throughput amplicon sequencing techniques were consistent that roadway stormwater runoff was not the primary contributor of microbial loading to the stream. Further studies of additional watersheds with distinct characteristics are needed to validate these findings. Understanding gained in this study could support the development of more effective strategies for stormwater management in sensitive watersheds. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Evaluation of ATP measurements to detect microbial ingress by wastewater and surface water in drinking water.

PubMed

Vang, Óluva K; Corfitzen, Charlotte B; Smith, Christian; Albrechtsen, Hans-Jørgen

2014-11-01

Fast and reliable methods are required for monitoring of microbial drinking water quality in order to protect public health. Adenosine triphosphate (ATP) was investigated as a potential real-time parameter for detecting microbial ingress in drinking water contaminated with wastewater or surface water. To investigate the ability of the ATP assay in detecting different contamination types, the contaminant was diluted with non-chlorinated drinking water. Wastewater, diluted at 10(4) in drinking water, was detected with the ATP assay, as well as 10(2) to 10(3) times diluted surface water. To improve the performance of the ATP assay in detecting microbial ingress in drinking water, different approaches were investigated, i.e. quantifying microbial ATP or applying reagents of different sensitivities to reduce measurement variations; however, none of these approaches contributed significantly in this respect. Compared to traditional microbiological methods, the ATP assay could detect wastewater and surface water in drinking water to a higher degree than total direct counts (TDCs), while both heterotrophic plate counts (HPC 22 °C and HPC 37 °C) and Colilert-18 (Escherichia coli and coliforms) were more sensitive than the ATP measurements, though with much longer response times. Continuous sampling combined with ATP measurements displays definite monitoring potential for microbial drinking water quality, since microbial ingress in drinking water can be detected in real-time with ATP measurements. The ability of the ATP assay to detect microbial ingress is influenced by both the ATP load from the contaminant itself and the ATP concentration in the specific drinking water. Consequently, a low ATP concentration of the specific drinking water facilitates a better detection of a potential contamination of the water supply with the ATP assay. Copyright © 2014 Elsevier Ltd. All rights reserved.

Inactivation of Salmonella in tomato stem scars by organic acid wash and chitosan-allyl isothiocyanate coating

USDA-ARS?s Scientific Manuscript database

The objective of this study was to evaluate inactivation of inoculated Salmonella enterica on tomato stem scars exploiting integrated treatment of organic acid wash (AW) followed by chitosan-allyl isothiocyanate (CT-AIT) coating. The treatment effect on microbial loads and fruit quality during 21 d...

Denitrification alternates between a source and sink of nitrous oxide in the hypolimnion of a thermally stratified reservoir

EPA Science Inventory

Nitrogen loading from developed watersheds to aquatic ecosystems can stimulate microbial denitrification, a process which reduces nitrate (NO3-) to dinitrogen (N2) or nitrous oxide (N2O), the latter a potent greenhouse gas. While aquatic ecosystems are a globally significant sou...

Seasonal and spatial patterns in coupled nitrification-denitrification rates in a large Great Lakes coastal system: The St. Louis River Estuary

EPA Science Inventory

Anthropogenic inputs of excess nitrogen (N) to aquatic systems are detrimental, but aquatic plants and sediments have the potential to mitigate N-loading. Sediment processes are driven by microbially mediated N-cycling. Coastal embayments purportedly play a significant role in N-...

Restoration and Purification of Dissolved Organic Nitrogen by Bacteria and Phytoremediation in Shallow Eutrophic Lakes Sediments

NASA Astrophysics Data System (ADS)

Li, Xin; Yue, Yi

2018-06-01

Endogenous organic nitrogen loadings in lake sediments have increased with human activity in recent decades. A 6-month field study from two disparate shallow eutrophic lakes could partly reveal these issues by analysing seasonal variations of biodegradation and phytoremediation in the sediment. This paper describes the relationship between oxidation reduction potential, temperature, microbial activity and phytoremediation in nitrogen cycling by calculation degradative index of dissolved organic nitrogen and amino acid decomposition. The index was being positive in winter and negative in summer while closely positive correlated with biodegradation. Our analysis revealed that rather than anoxic condition, biomass is the primary factor to dissolved organic nitrogen distribution and decomposition. Some major amino acids statistics also confirm the above view. The comparisons of organic nitrogen and amino acid in abundance and seasons in situ provides that demonstrated plants cue important for nitrogen removal by their roots adsorption and immobilization. In conclusion, enhanced microbial activity and phytoremediation with the seasons will reduce the endogenous nitrogen loadings by the coupled mineralization and diagenetic process.

High microbial loads found in minimally-processed sliced mushrooms from Italian market.

PubMed

Jiang, Haiyang; Miraglia, Dino; Ranucci, David; Donnini, Domizia; Roila, Rossana; Branciari, Raffaella; Li, Cheng

2018-03-31

There is an increased consumer interest in minimally processed vegetables that has led to the development of products, such as pre-cut sliced mushrooms. Few data are available on the hygienic condition and the presence of foodborne pathogens in such products. Therefore, the current study aimed to evaluate the safety and hygienic characteristics of both ready-to-eat and ready-to-cook, pre-cut sliced mushrooms obtained from a local Italian market. For the evaluation of the hygienic condition, the aerobic mesophilic bacteria, aerobic psychrotrophic bacteria and Escherichia coli enumerations were performed. Salmonella spp., Listeria monocytogenes and Campylobacter spp. were considered in the assessment of the foodborne pathogens. High microbial loads were detected, including counts higher than 5 log CFU/g for E. coli and 6 log CFU/g for the other bacteria counts considered, but no pathogens were found. Ready-to-eat and ready-to-cook products differed only for aerobic mesophilic counts (7.87 and 8.26 log CFU/g, respectively, P=0.003). Strategies to enhance the hygienic level of the mushrooms, particularly the ready-to-eat products, are needed.

High microbial loads found in minimally-processed sliced mushrooms from Italian market

PubMed Central

Jiang, Haiyang; Miraglia, Dino; Ranucci, David; Donnini, Domizia; Roila, Rossana; Branciari, Raffaella; Li, Cheng

2018-01-01

There is an increased consumer interest in minimally processed vegetables that has led to the development of products, such as pre-cut sliced mushrooms. Few data are available on the hygienic condition and the presence of foodborne pathogens in such products. Therefore, the current study aimed to evaluate the safety and hygienic characteristics of both ready-to-eat and ready-to-cook, pre-cut sliced mushrooms obtained from a local Italian market. For the evaluation of the hygienic condition, the aerobic mesophilic bacteria, aerobic psychrotrophic bacteria and Escherichia coli enumerations were performed. Salmonella spp., Listeria monocytogenes and Campylobacter spp. were considered in the assessment of the foodborne pathogens. High microbial loads were detected, including counts higher than 5 log CFU/g for E. coli and 6 log CFU/g for the other bacteria counts considered, but no pathogens were found. Ready-to-eat and ready-to-cook products differed only for aerobic mesophilic counts (7.87 and 8.26 log CFU/g, respectively, P=0.003). Strategies to enhance the hygienic level of the mushrooms, particularly the ready-to-eat products, are needed. PMID:29732334

Effect of gamma irradiation on microbial load, physicochemical and sensory characteristics of soybeans (Glycine max L. Merrill)

NASA Astrophysics Data System (ADS)

Yun, Juan; Li, Xihong; Fan, Xuetong; Tang, Yao; Xiao, Yao; Wan, Sen

2012-08-01

Gamma irradiation is highly effective in inactivating microorganisms in various foods and offers a safe alternative method of food decontamination. In the present study, soybeans (Glycine max L. Merrill) were treated with 0, 1.0, 3.0, 5.0 and 10.0 KGy of gamma irradiation. Microbial populations on soybeans, isoflavone, tocopherol contents, raffinose family oligosaccharides, color and sensory properties were evaluated as a function of irradiation dose. The results indicated that gamma irradiation reduced aerobic bacterial and fungal load. Irradiation at the doses applied did not cause any significant change (p>0.05) in the contents of isoflavone of soybeans, but decreased tocopherol contents. The content of key flatulence-producing raffinose family oligosaccharides in irradiated soybeans (10.0 kGy) decreased by 82.1% compared to the control. Sensory analysis showed that the odor of the soybeans was organoleptically acceptable at doses up to 5.0 kGy and no significant differences were observed between irradiated and nonirradiated samples in flavor, texture and color after irradiation.

Optimal growth condition of earthworms and their vermicompost features during recycling of five different fresh fruit and vegetable wastes.

PubMed

Huang, Kui; Xia, Hui; Li, Fusheng; Wei, Yongfen; Cui, Guangyu; Fu, Xiaoyong; Chen, Xuemin

2016-07-01

This study aimed to promote vermicomposting performance for recycling fresh fruit and vegetable wastes (FVWs) and to assess microbial population and community of final products. Five fresh FVWs including banana peels, cabbage, lettuce, potato, and watermelon peels were chosen as earthworms' food. The fate test of earthworms showed that 30 g fresh FVWs/day was the optimal loading and the banana peels was harmful for the survival of Eisenia fetida. The followed vermicomposting test revealed lower contents of total carbon and weaker microbial activity in final vermicomposts, relative to those in compared systems without earthworms worked. The leachate from FVWs carried away great amounts of nutrients from reactors. Additionally, different fresh FVWs displayed dissimilar stabilization process. Molecular biological approaches revealed that earthworms could broaden bacterial diversity in their products, with significant greater populations of actinobacteria and ammonia oxidizing bacteria than in control. This study evidences that vermicomposting efficiency differs with the types and loadings of fresh FVWs and vermicomposts are rich in agricultural probiotics.

Performance, carotenoids yield and microbial population dynamics in a photobioreactor system treating acidic wastewater: Effect of hydraulic retention time (HRT) and organic loading rate (OLR).

PubMed

Liu, Shuli; Zhang, Guangming; Zhang, Jie; Li, Xiangkun; Li, Jianzheng

2016-01-01

Effects of hydraulic retention time (HRT) and influent organic loading rate (OLR) were investigated in a photobioreactor containing PNSB (Rhodopseudomonas palustris)-chemoheterotrophic bacteria to treat volatile fatty acid wastewater. Pollutants removal, biomass production and carotenoids yield in different phases were investigated in together with functional microbial population dynamics. The results indicated that properly decreasing HRT and increasing OLR improved the nutrient removal performance as well as the biomass and carotenoids productions. 85.7% COD, 89.9% TN and 91.8% TP removals were achieved under the optimal HRT of 48h and OLR of 2.51g/L/d. Meanwhile, the highest biomass production and carotenoids yield were 2719.3mg/L and 3.91mg/g-biomass respectively. In addition, HRT and OLR have obvious impacts on PNSB and total bacteria dynamics. Statistical analyses indicated that the COD removal exhibited a positive relationship with OLR, biomass and carotenoids production. PNSB/total bacteria ratio had a positive correlation with the carotenoids yield. Copyright © 2015 Elsevier Ltd. All rights reserved.

Gamma radiation effects on commercial Mexican bread making wheat flour

NASA Astrophysics Data System (ADS)

Agúndez-Arvizu, Z.; Fernández-Ramírez, M. V.; Arce-Corrales, M. E.; Cruz-Zaragoza, E.; Meléndrez, R.; Chernov, V.; Barboza-Flores, M.

2006-04-01

Gamma irradiation is considered to be an alternative method for food preservation to prevent food spoilage, insect infestation and capable of reducing the microbial load. In the present investigation, commercial Mexican bread making wheat flour was irradiated at 1.0 kGy using a 60C Gammabeam 651 PT irradiator facility. No changes were detected in moisture, protein and ashes in gamma irradiated samples as compared to those of non-irradiated samples. Slight radiation effects were observed in the alveogram values and farinograph properties; the falling number decreased 11%, the absorption as well as the mixing tolerance were practically unchanged by irradiation. An increase of 15% in the stability value and a 29% in the dough development time were observed. Also the deformation energy decreased 7% with no change at all in the tenacity/extensibility factor. Total aerobic, yeast and mold counts were reduced 96%, 25% and 75%; respectively by the irradiation process. The obtained results confirm that gamma irradiation is effective in reducing the microbial load in bread making wheat flour without a significant change in the physicochemical and baking properties.

Dominance of candidate Saccharibacteria in a membrane bioreactor treating medium age landfill leachate: Effects of organic load on microbial communities, hydrolytic potential and extracellular polymeric substances.

PubMed

Remmas, Nikolaos; Melidis, Paraschos; Zerva, Ioanna; Kristoffersen, Jon Bent; Nikolaki, Sofia; Tsiamis, George; Ntougias, Spyridon

2017-08-01

A membrane bioreactor (MBR), accomplishing high nitrogen removal efficiencies, was evaluated under various landfill leachate concentrations (50, 75 and 100% v/v). Proteinous and carbohydrate extracellular polymeric substances (EPS) and soluble microbial product (SMP) were strongly correlated (p<0.01) with organic load, salinity and NH 4 + -N. Exceptionally high β-glucosidase activities (6700-10,100Ug -1 ) were determined during MBR operation with 50% v/v leachate, as a result of the low organic carbon availability that extendedly induced β-glucosidases to breakdown the least biodegradable organic fraction. Illumina sequencing revealed that candidate Saccharibacteria were dominant, independently of the leachate concentration applied, whereas other microbiota (21.2% of total reads) disappeared when undiluted leachate was used. Fungal taxa shifted from a Saccharomyces- to a newly-described Cryptomycota-based community with increasing leachate concentration. Indeed, this is the first report on the dominance of candidate Saccharibacteria and on the examination of their metabolic behavior in a bioreactor treating real wastewater. Copyright © 2017 Elsevier Ltd. All rights reserved.

Methane gas generation from waste water extraction process of crude palm oil in experimental digesters

NASA Astrophysics Data System (ADS)

Dillon, A.; Penafiel, R.; Garzón, P. V.; Ochoa, V.

2015-12-01

Industrial processes to extract crude palm oil, generates large amounts of waste water. High concentrations of COD, ST, SV, NH4 + and low solubility of O2, make the treatment of these effluents starts with anaerobic processes. The anaerobic digestion process has several advantages over aerobic degradation: lower operating costs (not aeration), low sludge production, methane gas generation. The 4 stages of anaerobic digestion are: hydrolysis, acidogenic, acetogenesis and methanogenesis. Through the action of enzymes synthesized by microbial consortia are met. The products of each step to serve as reagents is conducted as follows. The organic load times and cell hydraulic retention, solids content, nutrient availability, pH and temperature are factors that influence directly in biodigesters. The objectives of this presentation is to; characterize the microbial inoculum and water (from palm oil wasted water) to be used in biodigestores, make specific methanogenic activity in bioassays, acclimatize the microorganisms to produce methane gas using basal mineral medium with acetate for the input power, and to determine the production of methane gas digesters high organic load.

Effects of organic loading rate on biogas production from macroalgae: Performance and microbial community structure.

PubMed

Sun, Meng-Ting; Fan, Xiao-Lei; Zhao, Xiao-Xian; Fu, Shan-Fei; He, Shuai; Manasa, M R K; Guo, Rong-Bo

2017-07-01

Macroalgae biomass has been considered as a promising feedstock for biogas production. In order to improve the efficiency of anaerobic digestion (AD) of macroalgae, semi-continuous fermentation was conducted to examine the effects of organic loading rate (OLR) on biogas production from Macrocystis pyrifer. Results showed that, under OLRs of 1.37, 2.74, 4.12 and 6.85kgVS substrate /(m 3 ·d), the average unit biogas yields were 438.9, 477.3, 480.1 and 188.7mL/(gVS substrate d), respectively. It indicated that biogas production was promoted by the increased OLR in an appropriate range while inhibited by the OLR beyond the appropriate range. The investigation on physical-chemical parameters revealed that unfavorable VFAs concentration, pH and salinity might be the main causes for system failure due to the overrange OLR, while the total phenols failed to reach the inhibitory concentration. Microbial community analysis demonstrated that several bacterial and archaeal phyla altered with increase in OLR apparently. Copyright © 2017 Elsevier Ltd. All rights reserved.

Organic loading rate impact on biohydrogen production and microbial communities at anaerobic fluidized thermophilic bed reactors treating sugarcane stillage.

PubMed

Santos, Samantha Christine; Rosa, Paula Rúbia Ferreira; Sakamoto, Isabel Kimiko; Varesche, Maria Bernadete Amâncio; Silva, Edson Luiz

2014-05-01

This study aimed to evaluate the effect of high organic loading rates (OLR) (60.0-480.00 kg COD m(-3)d(-1)) on biohydrogen production at 55°C, from sugarcane stillage for 15,000 and 20,000 mg CODL(-1), in two anaerobic fluidized bed reactors (AFBR1 and AFBR2). It was obtained, for H2 yield and content, a decreasing trend by increasing the OLR. The maximum H2 yield was observed in AFBR1 (2.23 mmol g COD added(-1)). The volumetric H2 production was proportionally related to the applied hydraulic retention time (HRT) of 6, 4, 2 and 1h and verified in AFBR1 the highest value (1.49 L H2 h(-1)L(-1)). Among the organic acids obtained, there was a predominance of lactic acid (7.5-22.5%) and butyric acid (9.4-23.8%). The microbial population was set with hydrogen-producing fermenters (Megasphaera sp.) and other organisms (Lactobacillus sp.). Copyright © 2014 Elsevier Ltd. All rights reserved.

Investigation of soluble microbial products in a full-scale UASB reactor running at low organic loading rate.

PubMed

Zhou, Weili; Wu, Bingtao; She, Qianhong; Chi, Lina; Zhang, Zhenjia

2009-07-01

Investigation on a full-scale UASB treating industrial wastewater at a low organic loading rate (OLR) was conducted. Excellent treatment performance was achieved when treating the evaporator condensate of distillery wastewater at the OLR of less than 1 kg COD/m(3)d. Anaerobic effluent could be discharged without further treatment, which saved energy and running cost considerably. GC-MS analysis showed that the soluble microbial products (SMPs) were decreased to a low level at the low OLR. The main SMP in the anaerobic effluent were long chain carbohydrates and esters, accounting for 55-65% of the total organic matters. Anaerobic SMP was more complex than the aerobic ones. Soluble COD, protein and polysaccharide showed an obvious decrease at the sludge layer from 10 to 15m despite the low MLSS/MLVSS content. Methanogens were found to be predominant in this layer, which indicated that the methanogens might be the main consumers of the SMP in anaerobic reactors. Economic comparison confirmed that the anaerobic treatment at low OLR could be a good option.

Qualitative analysis of the vaginal microbiota of healthy cattle and cattle with genital-tract disease.

PubMed

Rodrigues, N F; Kästle, J; Coutinho, T J D; Amorim, A T; Campos, G B; Santos, V M; Marques, L M; Timenetsky, J; de Farias, S T

2015-06-12

The microbial community of the reproductive appara-tus, when known, can provide information about the health of the host. Metagenomics has been used to characterize and obtain genetic infor-mation about microbial communities in various environments and can relate certain diseases with changes in this community composition. In this study, samples of vaginal surface mucosal secretions were col-lected from five healthy cows and five cows that showed symptoms of reproductive disorders. Following high-throughput sequencing of the isolated microbial DNA, data were processed using the Mothur soft-ware to remove low-quality sequences and chimeras, and released to the Ribosomal Database Project for classification of operational taxo-nomic units (OTUs). Local BLASTn was performed and results were loaded into the MEGAN program for viewing profiles and taxonomic microbial attributes. The control profile comprised a total of 15 taxa, with Bacteroides, Enterobacteriaceae, and Victivallis comprising the highest representation of OTUs; the reproductive disorder-positive profile comprised 68 taxa, with Bacteroides, Enterobacteriaceae, His-tophilus, Victivallis, Alistipes, and Coriobacteriaceae being the taxa with the most OTU representation. A change was observed in both the community composition as well as in the microbial attributes of the profiles, suggesting that a relationship might exist between the patho-gen and representative taxa, reflecting the production of metabolites to disease progression.

Meta-analysis of Microbial Fuel Cells Using Waste Substrates.

PubMed

Dowdy, F Ryan; Kawakita, Ryan; Lange, Matthew; Simmons, Christopher W

2018-05-01

Microbial fuel cell experimentation using waste streams is an increasingly popular field of study. One obstacle to comparing studies has been the lack of consistent conventions for reporting results such that meta-analysis can be used for large groups of experiments. Here, 134 unique microbial fuel cell experiments using waste substrates were compiled for analysis. Findings include that coulombic efficiency correlates positively with volumetric power density (p < 0.001), negatively with working volume (p < 0.05), and positively with percentage removal of chemical oxygen demand (p < 0.005). Power density in mW/m 2 correlates positively with chemical oxygen demand loading (p < 0.005), and positively with maximum open-circuit voltage (p < 0.05). Finally, single-chamber versus double-chamber reactor configurations differ significantly in maximum open-circuit voltage (p < 0.005). Multiple linear regression to predict either power density or maximum open-circuit voltage produced no significant models due to the amount of multicollinearity between predictor variables. Results indicate that statistically relevant conclusions can be drawn from large microbial fuel cell datasets. Recommendations for future consistency in reporting results following a MIAMFCE convention (Minimum Information About a Microbial Fuel Cell Experiment) are included.

Effect of preservatives on microbial safety and quality of smoked blue catfish (Ictalurus furcatus) steaks during room-temperature storage.

PubMed

da Silva, Ligia V Antonia; Prinyawiwatkul, Witoon; King, Joan M; No, Hong Kyoon; Bankston, Joseph D; Ge, Beilei

2008-12-01

The microbial safety and quality of smoked blue catfish (Ictalurus furcatus) steaks treated with antimicrobials and antioxidants were examined during 6-week ambient storage. Five pre-smoking soaking treatments were applied: 25% NaCl and 1% ascorbic acid for 30 min or 1h, 3% sodium lactate with or without 5% rosemary extract for 30 min, and 5% sorbic acid alone for 30 min. After smoking, cooled catfish steaks were packed and analyzed at 0, 2, 4, and 6 weeks of ambient storage. Neither Listeria nor Salmonella was recovered from the smoked catfish steaks. Significant reductions (P<0.05) in total plate counts were observed in all treated samples, with those treated with 3% sodium lactate carrying the lowest microbial load. The rosemary extract-treated samples were the most stable against oxidation. All treated smoked catfish steaks had water activities less than 0.85; however, neither pH nor water activity changed significantly within each treatment group during storage (P> or 0.05). In conclusion, smoking/cooking effectively reduced microbial populations, and the use of antimicrobial agents and antioxidants, particularly 3% sodium lactate, could aid the control of microbial safety during storage, resulting in safe products for up to 6 weeks without refrigeration.

Experimental effect of ozone upon the microbial flora of commercially produced dairy fermented products.

PubMed

Alexopoulos, A; Plessas, S; Kourkoutas, Y; Stefanis, C; Vavias, S; Voidarou, C; Mantzourani, I; Bezirtzoglou, E

2017-04-04

Ozone was used to control spoilage microorganisms during the manufacturing of dairy products. Ozone stream was applied onto the surface of freshly filled yoghurt cups just before storage for curd development in order to prevent cross contamination from spoilage airborne microorganisms. Accordingly, brine solution was bubbled with ozone for various periods of time and used for ripening of white (feta type) cheese. Both products were subjected to a continuous monitoring of microbial load and also tested for their sensorial properties. In ozonated yoghurt samples there was a reduction in mould counts of approximately 0.6Logcfu/g (25.1%) by the end of the monitoring period in relation to the control samples. In white cheese ripened with ozonated brine (1.3mg/L O 3 , NaCl 5%) it seems that ozone treatment during the two months of observation reduced some of the mould load but without offering any advantages over the use of traditional brine (NaCl 7%). However, some sensorial alterations were observed, probably due to the organic load in the brine which deactivates ozone in early stages of application. It is concluded that, if the factors of time and concentration of ozone are configured properly, ozonation could be a promising approach safeguarding the production of some dairy products. Copyright © 2017 Elsevier B.V. All rights reserved.

The role of gut microbiota in the regulation of standard metabolic rate in female Periplaneta americana.

PubMed

Ayayee, Paul A; Ondrejech, Andrew; Keeney, George; Muñoz-Garcia, Agustí

2018-01-01

Insect gut microbiota contribute significantly to host nutritional ecology. Disrupting insect gut microbial assemblages impacts nutrient provisioning functions, and can potentially affect host standard metabolic rate (SMR), a measure of host energy balance. In this study, we evaluated the effect of disrupting gut microbial assemblages on the SMR of female Periplaneta americana cockroaches fed dog food (DF, high protein/carbohydrate (p/c) ratio), and cellulose-amended dog food (CADF, 30% dog food, 70% cellulose, low p/c ratio) diets, supplemented with none, low, or high antibiotic doses. Bacterial loads decreased significantly between diet types ( P = 0.04) and across antibiotic doses ( P = 0.04). There was a significant diet type x antibiotic dose interaction on SMR of females on both diets ( P = 0.05) by the end of the seven-day experimental period. In CADF-fed females, SMR decreased linearly with decreasing bacterial load. However, SMR of DF-fed females on the low dose was significantly higher than those in the control and high dose groups. This is interpreted as a diet-dependent response by low dose DF-fed females to the loss of nutritional services provided by gut bacteria. Severe reductions in bacterial load at high doses reduced SMR of females on both diet types. This study provides insights into the potential role of gut bacteria as modulators of host energy expenditure under varying dietary conditions.

Cobalt porphyrin-based material as methanol tolerant cathode in single chamber microbial fuel cells (SCMFCs)

NASA Astrophysics Data System (ADS)

Liu, Bingchuan; Brückner, Cristian; Lei, Yu; Cheng, Yue; Santoro, Carlo; Li, Baikun

2014-07-01

This study focused on the development of novel cathode material based on the pyrolysis of [meso-tetrakis(2-thienyl)porphyrinato]Co(II) (CoTTP) for use in single chamber microbial fuel cells (SCMFCs) to treat wastewater containing methanol. The cathodes produced at two loadings (0.5 and 1.0 mg cm-2) were examined in batch mode SCMFCs treating methanol of different concentrations (ranging from 0.005 to 0.04 M) over a 900 h operational period. Methanol was completely removed in SCMFCs, and the cycle duration was prolonged at high methanol concentrations, indicating methanol was used as fuel in SCMFCs. Methanol had more poisoning effects to the traditional platinum (Pt) cathodes than to the CoTTP cathodes. Specifically, power generations from SCMFCs with Pt cathodes gradually decreased over time, while the ones with CoTTP cathodes remained stable, even at the highest methanol concentration (0.04 M). Cathode linear sweep voltammetry (LSVs) indicated that the electrocatalytic activity of the Pt cathode was suppressed by methanol. Higher CoTTP loadings had similar open circuit potential (OCP) but higher electrocatalytic activity than lower loadings. This study demonstrated that methanol can be co-digested with wastewater and converted to power in MFCs, and a novel cathode CoTTP catalyst exhibits higher tolerance towards methanol compared with traditional Pt catalyst.

Development and application of a hybrid inert/organic packing material for the biofiltration of composting off-gases mimics.

PubMed

Hernández, Jerónimo; Prado, Oscar J; Almarcha, Manuel; Lafuente, Javier; Gabriel, David

2010-06-15

The performance of three biofilters (BF1-BF3) packed with a new hybrid (inert/organic) packing material that consists of spherical argyle pellets covered with compost was examined in different operational scenarios and compared with a biofilter packed with pine bark (BF4). BF1, BF2 and BF4 were inoculated with an enriched microbial population, while BF3 was inoculated with sludge from a wastewater treatment plant. A gas mixture containing ammonia and six VOCs was fed to the reactors with N-NH(3) loads ranging from 0 to 10 g N/m(3)h and a VOCs load of around 10 g C/m(3)h. A profound analysis of the fate of nitrogen was performed in all four reactors. Results show that the biofilters packed with the hybrid packing material and inoculated with the microbial pre-adapted population (BF1 and BF2) achieved the highest nitrification rates and VOCs removal efficiencies. In BF3, nitratation was inhibited during most of the study, while only slight evidence of nitrification could be observed in BF4. All four reactors were able to treat the VOCs mixture with efficiencies greater than 80% during the entire experimental period, regardless of the inlet ammonia load. Copyright 2010 Elsevier B.V. All rights reserved.

Microbiological properties and biogenic amines of whole pike-perch (Sander lucioperca, linnaeus 1758): a perspective on fish safety during postharvest handling practices and frozen storage.

PubMed

Ehsani, Ali; Jasour, Mohammad Sedigh

2012-12-01

The biogenic amines (tyramine, histamine, cadaverine, and puterscine) and microbiological properties (mesophilic, psychrotrophic, and Pseudomonas spp.) of whole pike-perch (Sander lucioperca) was investigated during 2 d prestorage icing and 90 d frozen storage (-24 °C). At the end of ice storage, a noticeable increase only was found for puterscine level (P < 0.05), and microbial loads of fish increased in comparison with fresh fish (P < 0.05). During the frozen storage, as time passed, a continuous increase of biogenic amines and decrease of bacterial load (except for Pseudomonas spp. at the last 30 d) was detected (P < 0.05). The total contents of biogenic amines ranged from 6.24 to 91.76 μg/g during the investigated period. Puterscine was the major amine detected in pike-perch and its concentration varied between 1.75 and 56.95 μg/g; due to a more step-wise increase it was a good quality indicator. At the end of storage, all of the obtained values are below the tolerable maximum amounts based on available regulations. Based on biogenic amines content and microbial load, it could be concluded that pike-perch can be consumed without any health risks after 2 d icing condition and 90 d frozen storage. © 2012 Institute of Food Technologists®

Microbial nitrogen sinks in the water column of a large coastal hypoxic area, the Gulf of Mexico "Dead Zone"

NASA Astrophysics Data System (ADS)

Rogener, M. K.; Roberts, B. J.; Rabalais, N. N.; Stewart, F. J.; Joye, S. B.

2016-02-01

Excess nitrogen in coastal environments leads to eutrophication, harmful algal blooms, habitat loss, oxygen depletion and reductions in biodiversity. As such, biological nitrogen (N) removal through the microbially-mediated process of denitrification is a critical ecosystem function that can mitigate the negative consequences of excess nitrogen loading. However, denitrification can produce nitrous oxide, a potent greenhouse gas, as a byproduct under some environmental conditions. To understand how excess nitrogen loading impacts denitrification, we measured rates of this process in the water column of the Gulf of Mexico "Dead Zone" three times over the summer of 2015. The Dead Zone is generated by excessive nitrogen loading from the Mississippi River co-occurring with strong water column stratification, which leads to a large summer-time hypoxic/anoxic area at the mouth of the river and along the coast of Louisiana. Rates of denitrification ranged from 31 to 153 nmol L-1 d-1. Dead Zone waters are also enriched in methane and aerobic methane oxidation rates ranged from 0.1 to 4.3 nmol L-1 d-1. Maximal denitrification rates were observed at stations with the lowest oxygen concentrations and highest methane oxidation rates, suggesting a potential coupling between nitrate reduction and methane oxidation which both scrubs reactive N and methane from the system, thus performing a duel ecosystem service.

Impact of fouling on the decline of aeration efficiency under different operational conditions at WRRFs.

PubMed

Garrido-Baserba, Manel; Asvapathanagul, Pitiporn; Park, Hee-Deung; Kim, Taek-Seung; Baquero-Rodriguez, G Andres; Olson, Betty H; Rosso, Diego

2018-10-15

Biofilm formation influences the most energy-demanding process in the waste water treatment cycle. Biofilm growth on the surface of wastewater aeration diffusers in water resource recovery facilities (WRRFs) can increase the energy requirements up to 50% in less than 2 years. The impact of biofilms in aeration diffusers was quantified and assessed for first time using molecular tools (i.e., Energy-dispersive X-ray, Ra and RMS and Pyrosequencing) and state-of-the-art techniques (i.e., EPS quantification, Hydrophobicity and DNA quantification). To provide a better understanding and quantitative connections between biological activity and aeration energy efficiency, two replicates of the most common diffusers were installed and tested in two different operational conditions (higher and lower organic loading rate processes) during 15 months. Different scenarios and conditions provided for first time comprehensive understanding of the major factors contributing to diffuser fouling. The array of analysis suggested that higher loading conditions can promote specialized microbial populations to halve aeration efficiency parameters (i.e., αF) in comparison to lower loading conditions. Biofilms adapted to certain operational conditions can trigger changes in diffuser membrane properties (i.e., biological enhanced roughness and hydrophobicity) and enhance EPS growth rates. Improved understanding of the effects of scaling, biofouling, aging and microbial population shifts on the decrease in aeration efficiency is provided. Copyright © 2018 Elsevier B.V. All rights reserved.

A new apparatus to induce lysis of planktonic microbial cells by shock compression, cavitation and spray

NASA Astrophysics Data System (ADS)

Schiffer, A.; Gardner, M. N.; Lynn, R. H.; Tagarielli, V. L.

2017-03-01

Experiments were conducted on an aqueous growth medium containing cultures of Escherichia coli (E. coli) XL1-Blue, to investigate, in a single experiment, the effect of two types of dynamic mechanical loading on cellular integrity. A bespoke shock tube was used to subject separate portions of a planktonic bacterial culture to two different loading sequences: (i) shock compression followed by cavitation, and (ii) shock compression followed by spray. The apparatus allows the generation of an adjustable loading shock wave of magnitude up to 300 MPa in a sterile laboratory environment. Cultures of E. coli were tested with this apparatus and the spread-plate technique was used to measure the survivability after mechanical loading. The loading sequence (ii) gave higher mortality than (i), suggesting that the bacteria are more vulnerable to shear deformation and cavitation than to hydrostatic compression. We present the results of preliminary experiments and suggestions for further experimental work; we discuss the potential applications of this technique to sterilize large volumes of fluid samples.

Effect of natural ageing on surface of silver loaded TPE and its influence in antimicrobial efficacy

NASA Astrophysics Data System (ADS)

Tomacheski, Daiane; Pittol, Michele; Simões, Douglas Naue; Ribeiro, Vanda Ferreira; Santana, Ruth Marlene Campomanes

2017-05-01

The aim of this study is to characterize the modifications in silver loaded TPE surfaces exposed to weathering and their relation to susceptibility to microbial attack. Silver loaded TPE materials were exposed to natural ageing for nine months and modifications in antimicrobial properties and surface characteristics were evaluated. Chemical changes were investigated by using the infrared spectra. The average surface roughness and topography were determined by atomic force microscopy. Contact angle was measured to verify wettability conditions and surface free energy (SFE). After nine months of exposure, a decrease in the antimicrobial properties of loaded TPE compounds was observed. A reduction in surface roughness and improvement in wettability and high values of polar component of SFE were verified. The best antibacterial action was noticed in the sample with high Lewis acid force, lower roughness and lower carbonyl index.

Long-term reactive nitrogen loading alters soil carbon and microbial community properties in a subalpine forest ecosystem

USGS Publications Warehouse

Boot, Claudia M.; Hall, Ed K.; Denef, Karolien; Baron, Jill S.

2016-01-01

Elevated nitrogen (N) deposition due to increased fossil fuel combustion and agricultural practices has altered global carbon (C) cycling. Additions of reactive N to N-limited environments are typically accompanied by increases in plant biomass. Soil C dynamics, however, have shown a range of different responses to the addition of reactive N that seem to be ecosystem dependent. We evaluated the effect of N amendments on biogeochemical characteristics and microbial responses of subalpine forest organic soils in order to develop a mechanistic understanding of how soils are affected by N amendments in subalpine ecosystems. We measured a suite of responses across three years (2011–2013) during two seasons (spring and fall). Following 17 years of N amendments, fertilized soils were more acidic (control mean 5.09, fertilized mean 4.68), and had lower %C (control mean 33.7% C, fertilized mean 29.8% C) and microbial biomass C by 22% relative to control plots. Shifts in biogeochemical properties in fertilized plots were associated with an altered microbial community driven by reduced arbuscular mycorrhizal (control mean 3.2 mol%, fertilized mean 2.5 mol%) and saprotrophic fungal groups (control mean 17.0 mol%, fertilized mean 15.2 mol%), as well as a decrease in N degrading microbial enzyme activity. Our results suggest that decreases in soil C in subalpine forests were in part driven by increased microbial degradation of soil organic matter and reduced inputs to soil organic matter in the form of microbial biomass.

The impact of Rhodiola rosea on the gut microbial community of Drosophila melanogaster.

PubMed

Labachyan, Khachik E; Kiani, Dara; Sevrioukov, Evgueni A; Schriner, Samuel E; Jafari, Mahtab

2018-01-01

The root extract of Rhodiola rosea has historically been used in Europe and Asia as an adaptogen, and similar to ginseng and Shisandra , shown to display numerous health benefits in humans, such as decreasing fatigue and anxiety while improving mood, memory, and stamina. A similar extract in the Rhodiola family, Rhodiola crenulata , has previously been shown to confer positive effects on the gut homeostasis of the fruit fly, Drosophila melanogaster. Although, R. rosea has been shown to extend lifespan of many organisms such as fruit flies, worms and yeast, its anti-aging mechanism remains uncertain. Using D. melanogaster as our model system, the purpose of this work was to examine whether the anti-aging properties of R. rosea are due to its impact on the microbial composition of the fly gut. Rhodiola rosea treatment significantly increased the abundance of Acetobacter , while subsequently decreasing the abundance of Lactobacillales of the fly gut at 10 and 40 days of age. Additionally, supplementation of the extract decreased the total culturable bacterial load of the fly gut, while increasing the overall quantifiable bacterial load. The extract did not display any antimicrobial activity when disk diffusion tests were performed on bacteria belonging to Microbacterium , Bacillus , and Lactococcus . Under standard and conventional rearing conditions, supplementation of R. rosea significantly alters the microbial community of the fly gut, but without any general antibacterial activity. Further studies should investigate whether R. rosea impacts the gut immunity across multiple animal models and ages.

The microbiology of the peri-implant sulcus following successful implantation of oral prosthetic treatments.

PubMed

Asadzadeh, Nafiseh; Naderynasab, Mahbobeh; Fard, Fojhan Ghorbanian; Rohi, Ali; Haghi, Hamidreza Rajati

2012-01-01

Oral implants are widely used in partially and fully edentulous patients; however, the integration of an implant can be endangered by factors such as intraoral bacteria or inflammatory reactions. The purpose of this study was to evaluate the microbial flora present in the sulcus around dental implants and to assess the relationship between gingival health and microbial flora present. Twenty patients who had received oral implants with no complications were followed for a period of 9 months. Assessment of probing depth, the presence of bleeding on probing and microbial sampling from the peri-implant sulcus were performed at three different time points- 4 weeks after surgery, 1 month and 6 months after loading. The samples were taken by paper points and transferred to the microbiology lab in thioglyocolate cultures. In order to do a colony count and isolate the aerobic capnophilic and anerobic bacteria the samples were cultured and incubated on laboratory media. The colonies were also identified using various diagnostic tests. Alterations in the presence of various bacterial species over time and gum health were tested using analysis of variance (ANOVA) with Tukey's test post hoc. The average pocket depth for each patient ranged from 1.37 ± 0.39 mm to 2.55 ± 0.72 mm. The bacteria isolated from the cultured samples included aerobic, facultative anerobic, obligate anerobic and capnophilic bacteria. The anerobic conditions created in the peri-implant sulcus might with time enhance the number of anerobic bacteria present following dental implant loading.

The microbiological safety of duckweed fed chickens: a risk assessment of using duckweed reared on domestic wastewater as a protein source in broiler chickens

NASA Astrophysics Data System (ADS)

Moyo, S.; Dalu, J. M.; Ndamba, J.

The possibility of transmission of pathogens from duckweed supplemented feed to chickens and consequently to the human consumer necessitated the microbiological testing of duckweed fed chickens. This assessment was thus done to determine whether there is transmission of pathogens from the duckweed supplemented feed to the chickens; determine whether such infection would be systemic or be confined to the gastro-intestinal tract of the birds; and to investigate the microbial load and distribution of the microbes with age. The study birds were sacrificed at 3, 6, 8 and 10 weeks of age and examined for the indicator organisms Escherichia coli and Salmonella spp. There was no discernible pattern in the microbial load of both the duckweed fed chickens and control birds with age although the control birds sampled clearly had a lower microbial load than the experimental flock. Some Salmonella and two enteropathogenic E. coli strains were isolated from control and experimental sub-samples at 3 weeks. There were no Salmonellae isolated in the subsequent batches of birds and feed although a number of E. coli were isolated. More isolates were obtained from the three weeks’ sub-samples (collected during wet weather) than from all the other sub-samples. The use of duckweed at this inclusion rate under the processing conditions at Nemanwa was thus concluded to be microbiologically safe as long as due caution is exercised during the processing of the duckweed and handling of the birds. There are indications that the chickens may get contaminated especially during wet weather as evidenced by the isolation of E. coli and Salmonella spp from the first batch sub-samples. This was attributed to poor environmental sanitation at the plant particularly in view of the prevailing wet conditions at the time.

Long-term monitoring of waterborne pathogens and microbial source tracking markers in paired agricultural watersheds under controlled and conventional tile drainage management.

PubMed

Wilkes, Graham; Brassard, Julie; Edge, Thomas A; Gannon, Victor; Gottschall, Natalie; Jokinen, Cassandra C; Jones, Tineke H; Khan, Izhar U H; Marti, Romain; Sunohara, Mark D; Topp, Edward; Lapen, David R

2014-06-01

Surface waters from paired agricultural watersheds under controlled tile drainage (CTD) and uncontrolled tile drainage (UCTD) were monitored over 7 years in order to determine if there was an effect of CTD (imposed during the growing season) on occurrences and loadings of bacterial and viral pathogens, coliphages, and microbial source tracking markers. There were significantly lower occurrences of human, ruminant, and livestock (ruminant plus pig) Bacteroidales markers in the CTD watershed in relation to the UCTD watershed. As for pathogens, there were significantly lower occurrences of Salmonella spp. and Arcobacter spp. in the CTD watershed. There were no instances where there were significantly higher quantitative loadings of any microbial target in the CTD watershed, except for F-specific DNA (F-DNA) and F-RNA coliphages, perhaps as a result of fecal inputs from a hobby farm independent of the drainage practice treatments. There was lower loading of the ruminant marker in the CTD watershed in relation to the UCTD system, and results were significant at the level P = 0.06. The odds of Salmonella spp. occurring increased when a ruminant marker was present relative to when the ruminant marker was absent, yet for Arcobacter spp., the odds of this pathogen occurring significantly decreased when a ruminant marker was present relative to when the ruminant marker was absent (but increased when a wildlife marker was present relative to when the wildlife marker was absent). Interestingly, the odds of norovirus GII (associated with human and swine) occurring in water increased significantly when a ruminant marker was present relative to when a ruminant marker was absent. Overall, this study suggests that fecal pollution from tile-drained fields to stream could be reduced by CTD utilization. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

The impact of cotton growing practices on soil microbiology and its relation to plant and soil health

NASA Astrophysics Data System (ADS)

Pereg, Lily

2013-04-01

Crop production and agricultural practices heavily impact the soil microbial communities, which differ among varying types of soils and environmental conditions. Soil-borne microbial communities in cotton production systems, as in every other cropping system, consist of microbial populations that may either be pathogenic, beneficial or neutral with respect to the cotton crop. Crop production practices have major roles in determining the composition of microbial communities and function of microbial populations in soils. The structure and function of any given microbial community is determined by various factors, including those that are influenced by farming and those not controlled by farming activities. Examples of the latter are environmental conditions such as soil type, temperature, daylight length and UV radiation, air humidity, atmospheric pressure and some abiotic features of the soil. On the other hand, crop production practices may determine other abiotic soil properties, such as water content, density, oxygen levels, mineral and elemental nutrient levels and the load of other crop-related soil amendments. Moreover, crop production highly influences the biotic properties of the soil and has a major role in determining the fate of soil-borne microbial communities associated with the crop plant. Various microbial strains react differently to the presence of certain plants and plant exudates. Therefore, the type of plant and crop rotations are important factors determining microbial communities. In addition, practice management, e.g. soil cultivation versus crop stubble retention, have a major effect on the soil conditions and, thus, on microbial community structure and function. All of the above-mentioned factors can lead to preferential selection of certain microbial population over others. It may affect not only the composition of microbial communities (diversity and abundance of microbial members) but also the function of the community (the ability of different microbes to perform certain activities). Therefore, agricultural practices may determine the ability of beneficial microbes to realise their plant growth promoting potential or the pathogenic expression of others. This presentation will review the current knowledge about the impact of cotton growing practices on microbial communities and soil health in different environments as well as endeavour to identify gaps worthwhile exploring in future research for promoting plant growth in healthy soils.

Autotrophic and heterotrophic nitrification-anoxic denitrification dominated the anoxic/oxic sewage treatment process during optimization for higher loading rate and energy savings.

PubMed

Zhang, Xueyu; Zheng, Shaokui; Zhang, Hangyu; Duan, Shoupeng

2018-04-30

This study clarified the dominant nitrogen (N)-transformation pathway and the key ammonia-oxidizing microbial species at three loading levels during optimization of the anoxic/oxic (A/O) process for sewage treatment. Comprehensive N-transformation activity analysis showed that ammonia oxidization was performed predominantly by aerobic chemolithotrophic and heterotrophic ammonia oxidization, whereas N 2 production was performed primarily by anoxic denitrification in the anoxic unit. The abundances of ammonia-oxidizing bacteria (AOB), nitrite-oxidizing bacteria, and anaerobic AOB in activated sludge reflected their activities on the basis of high-throughput sequencing data. AOB amoA gene clone libraries revealed that the predominant AOB species in sludge samples shifted from Nitrosomonas europaea (61% at the normal loading level) to Nitrosomonas oligotropha (58% and 81% at the two higher loading levels). Following isolation and sequencing, the predominant culturable heterotrophic AOB in sludge shifted from Agrobacterium tumefaciens (42% at the normal loading level) to Acinetobacter johnsonii (52% at the highest loading level). Copyright © 2018 Elsevier Ltd. All rights reserved.

Anticancer Potential of Nutraceutical Formulations in MNU-induced Mammary Cancer in Sprague Dawley Rats.

PubMed

Pitchaiah, Gummalla; Akula, Annapurna; Chandi, Vishala

2017-01-01

Nutraceuticals help in combating some of the major health problems of the century including cancer, and 'nutraceutical formulations' have led to the new era of medicine and health. To develop different nutraceutical formulations and to assess the anticancer potential of nutraceutical formulations in N-methyl-N-nitrosourea (MNU)-induced mammary cancer in Sprague Dawley rats. Different nutraceutical formulations were prepared using fine powders of amla, apple, garlic, onion, papaya, turmeric, and wheat grass with and without cow urine distillate. Total phenolic content, acute oral toxicity, and microbial load of nutraceutical formulations were assessed. The anticancer potential of nutraceutical formulations was evaluated against MNU-induced mammary cancer in female Sprague Dawley rats. Improvement in total phenolic content was significant ( P < 0.001) after self-fortification process. Toxicity studies showed that the nutraceutical formulations were safe to use in animals. Microbial load was within the limits. Significant longer tumor-free days ( P < 0.01), lower tumor incidence ( P < 0.01), lower tumor multiplicity ( P < 0.05) and tumor burden ( P < 0.01) were observed for nutraceutical formulation-treated groups. Combination of whole food-based nutraceuticals acted synergistically in the prevention of mammary cancer. Further, the process of fortification is novel and enhanced the anticancer potential of nutraceutical formulations. Nutraceuticals help in combating some of the major health problems of the century including cancer, and 'nutraceutical formulations' have led to the new era of medicine and health. In this study, different nutraceutical formulations using fine powders of amla, apple, garlic, onion, papaya, turmeric, and wheat grass with and without cow urine distillate. Total phenolic content, acute oral toxicity, and microbial load of nutraceutical formulations were assessed. The anticancer potential of nutraceutical formulations was evaluated against MNU-induced mammary cancer in female Sprague Dawley rats. Improvement in total phenolic content was observed after self-fortification process. Toxicity studies showed that the nutraceutical formulations were safe to use in animals. Microbial load was within the limits. Longer tumor-free days, lower tumor incidence, lower tumor multiplicity and tumor burden were observed for nutraceutical formulation-treated groups. This suggests that combination of whole food-based nutraceuticals acted synergistically in the prevention of mammary cancer. Further, the process of fortification enhanced the anticancer potential of nutraceutical formulations. Abbreviations used: HMNU: N-methyl-N-nitrosourea, CAM: Complementary and Alternative Medicine, NF: Nutraceutical Formulation, SFNF: Self-Fortitfied Nutraceutical Formulation, NFCUD: Nutraceutical Formulation fortified with Cow Urine Disstillate, SFNFCUD: Self-Fortified Nutraceutical Formulation fortified with Cow Urine Disstillate, CPCSEA: Committee for the Purpose of Control and Supervision of Experiments on Animals, OECD: Organisation for Economic Co-operation and Development, TPC: Total Phenolic Content, ANOVA: Analysis of Variance, GAE: Gallic Acid Equivalent, cfu/g: Colony forming unit per g.

Changes in abundance of heterotrophic and coliform bacteria resident in stored water bodies in relation to incoming bacterial loads following rain events.

PubMed

Martin, Anthony Richard; Coombes, Peter John; Harrison, Tracey Lee; Hugh Dunstan, R

2010-01-01

Microbial properties of harvested rainwater were assessed at two study sites at Newcastle on the east coast of Australia. The investigation monitored daily counts of heterotrophic bacteria (HPC), total coliforms and E. coli during a mid-winter month (July). Immediately after a major rainfall event, increases in bacterial loads were observed at both sites, followed by gradual reductions in numbers to prior baseline levels within 7 days. Baseline HPC levels ranged from 500-1000 cfu/mL for the sites evaluated, and the loads following rain peaked at 3590-6690 cfu/mL. Baseline levels of total coliforms ranged from 0-100 cfu/100 mL and peaked at 480-1200 cfu/100 mL following rain. At Site 1, there was no evidence of E. coli loading associated with the rain events assessed, and Site 2 had no detectable E.coli colonies at baseline, with a peak load of 17 cfu/100 mL following rain which again diminished to baseline levels. It was concluded that rainfall events contributed to the bacterial load in rainwater storage systems, but processes within the rainwater storage ensured these incoming loads were not sustained.

Monfort waste conversion demonstration. Quarterly progress report, April 1, 1977--June 30, 1977

DOE Office of Scientific and Technical Information (OSTI.GOV)

Turk, M.

1977-07-01

Progress in development of the mobile fermentation system at the Montfort cattle feedlots is reported. Fermentor startup was evaluated at operating conditions of 135/sup 0/F/57.2/sup 0/C with gradual increases in loading rates. An attempt was made to maintain the TVA (total volatile acid) concentration at a low level, but it became obvious that increases in loading rates could not be accomplished without a concomitant increase in TVA. Samples were also analyzed for heavy metals (Cu, Zn, Fe, Al) and S and P. Addition of FeCl/sub 3/ helped to reduce P, S, and TVA levels, making possible the maintenance of amore » healthy microbial colony capable of accepting increases in organic loading. (JGB)« less

Effect of γ irradiation on fungal load and aflatoxins reduction in red chillies

NASA Astrophysics Data System (ADS)

Iqbal, Shahzad Zafar; Bhatti, Ijaz Ahmad; Asi, Muhammad Rafique; Zuber, Mohammad; Shahid, Muhammad; Parveen, Ishrat

2013-01-01

Chillies are a very important cash crop of Pakistan. The effects of gamma irradiation on microbial load, aflatoxin B1 (AFB1) and total aflatoxins have been studied in chillies samples, collected from different districts of Punjab, Pakistan. Aflatoxins were analyzed using HPLC equipped with a fluorescence detector. The results revealed that among the Aspergillus species isolated, those belonging to section parasiticus were predominant. Gamma radiations of doses 2, 4 and 6 kGy were employed on fungi and chilli samples. The results have demonstrated that the dose of 6 kGy reduced the fungal load by 5 logs. Furthermore, 6 kGy reduced the level of AFB1 and total AFs in ground and whole chillies by 1-2 logs (α < 0.05).

Microbial response to high severity wildfire in the southwest United States

Treesearch

Steven T. Overby; Stephen C. Hart; Gregory S. Newman; Dana Erickson

2006-01-01

Southwest United States ponderosa pine (Pinus ponderosa Dougl. ex Laws) ecosystems have received great attention due to fuel conditions that increase the likelihood of large-scale wildfires with severe fire behavior. The fire season of 2002 demonstrated these extreme fuel load conditions with the largest fires in southwest history. The Jemez District of the Santa Fe...

Performance evaluation and microbial community analysis of the function and fate of ammonia in a sulfate-reducing EGSB reactor.

PubMed

Wang, Depeng; Liu, Bo; Ding, Xinchun; Sun, Xinbo; Liang, Zi; Sheng, Shixiong; Du, Lingfeng

2017-10-01

Ammonia is widely distributed in sulfate-reducing bioreactor dealing with sulfate wastewater, which shows potential effect on the metabolic pathway of sulfate and ammonia. This study investigates the sulfate-reducing efficiency and microbial community composition in the sulfate-reducing EGSB reactor with the increasing ammonia loading. Results indicated that, compared with low ammonia loading (166-666 mg/L), the sulfate and organic matter removal efficiencies were improved gradually with the appropriate ammonia loading (1000-2000 mg/L), which increased from 63.58 ± 3.81 to 71.08 ± 1.36% and from 66.24 ± 1.32 to 81.88 ± 1.83%, respectively. Meanwhile, with the appropriate ratio of ammonia and sulfate (1.5-3.0) and hydraulic retention time (21 h), the sulfate-reducing anaerobic ammonia oxidation (SRAO) process was occurred efficiently, inducing the accumulation of S 0 (270 mg/L) and the simultaneous ammonia removal (70.83%) in EGSB reactor. Moreover, the key sulfate-reducing bacteria (SRB) (Desulfovibrio) and denitrification bacteria (Pseudomonas and Alcaligenes) were responsible for the sulfate and nitrogen removal in these phases, which accounted for 3.66-5.54 and 3.85-9.13%, respectively. However, as the ammonia loading higher than 3000 mg/L (phases 9 and 10), the sulfate-reducing efficiency was decreased to only 28.3 ± 1.26% with the ammonia removal rate of 18.4 ± 3.37% in the EGSB reactor. Meanwhile, the predominant SRB in phases 9 and 10 were Desulfomicrobium (1.22-1.99%) and Desulfocurvus (4.0-5.46%), and the denitrification bacteria accounted for only 0.88% (phase 10), indicating the low nitrogen removal rate.

Bacterial Exchange in Household Washing Machines

PubMed Central

Callewaert, Chris; Van Nevel, Sam; Kerckhof, Frederiek-Maarten; Granitsiotis, Michael S.; Boon, Nico

2015-01-01

Household washing machines (WMs) launder soiled clothes and textiles, but do not sterilize them. We investigated the microbial exchange occurring in five household WMs. Samples from a new cotton T-shirt were laundered together with a normal laundry load. Analyses were performed on the influent water and the ingoing cotton samples, as well as the greywater and the washed cotton samples. The number of living bacteria was generally not lower in the WM effluent water as compared to the influent water. The laundering process caused a microbial exchange of influent water bacteria, skin-, and clothes-related bacteria and biofilm-related bacteria in the WM. A variety of biofilm-producing bacteria were enriched in the effluent after laundering, although their presence in the cotton sample was low. Nearly all bacterial genera detected on the initial cotton sample were still present in the washed cotton samples. A selection for typical skin- and clothes-related microbial species occurred in the cotton samples after laundering. Accordingly, malodour-causing microbial species might be further distributed to other clothes. The bacteria on the ingoing textiles contributed for a large part to the microbiome found in the textiles after laundering. PMID:26696989

Retardation of quality changes in camel meat sausages by phenolic compounds and phenolic extracts.

PubMed

Maqsood, Sajid; Manheem, Kusaimah; Abushelaibi, Aisha; Kadim, Isam Tawfik

2016-11-01

Impact of tannic acid (TA), date seed extract (DSE), catechin (CT) and green tea extract (GTE) on lipid oxidation, microbial load and textural properties of camel meat sausages during 12 days of refrigerated storage was investigated. TA and CT showed higher activities in all antioxidative assays compared to DSE and GTE. Lipid oxidation and microbial growth was higher for control sausages when compared to other samples. TA and CT at a level of 200 mg/kg were more effective in retarding lipid oxidation and lowering microbial count (P < 0.05). Sausages treated with TA and DSE were found to have higher hardness, gumminess and chewiness values compared to other treatments (P < 0.05). Addition of different phenolic compounds or extract did not influence the sensory color of sausages. Furthermore, sensory quality was also found to be superior in TA and CT treated sausages. Therefore, pure phenolic compounds (TA and CT) proved to be more effective in retaining microbial and sensorial qualities of camel meat sausages compared to phenolic extracts (GTE and DSE) over 12 days of storage at 4°C. © 2016 Japanese Society of Animal Science.

Environmental proteomics reveals taxonomic and functional changes in an enriched aquatic ecosystem.

PubMed

Northrop, Amanda C; Brooks, Rachel; Ellison, Aaron M; Gotelli, Nicholas J; Ballif, Bryan A

2017-10-01

Aquatic ecosystem enrichment can lead to distinct and irreversible changes to undesirable states. Understanding changes in active microbial community function and composition following organic-matter loading in enriched ecosystems can help identify biomarkers of such state changes. In a field experiment, we enriched replicate aquatic ecosystems in the pitchers of the northern pitcher plant, Sarracenia purpurea . Shotgun metaproteomics using a custom metagenomic database identified proteins, molecular pathways, and contributing microbial taxa that differentiated control ecosystems from those that were enriched. The number of microbial taxa contributing to protein expression was comparable between treatments; however, taxonomic evenness was higher in controls. Functionally active bacterial composition differed significantly among treatments and was more divergent in control pitchers than enriched pitchers. Aerobic and facultative anaerobic bacteria contributed most to identified proteins in control and enriched ecosystems, respectively. The molecular pathways and contributing taxa in enriched pitcher ecosystems were similar to those found in larger enriched aquatic ecosystems and are consistent with microbial processes occurring at the base of detrital food webs. Detectable differences between protein profiles of enriched and control ecosystems suggest that a time series of environmental proteomics data may identify protein biomarkers of impending state changes to enriched states.

Preparation and Application of LDPE/ZnO Nanocomposites for Extending Shelf Life of Fresh Strawberries

PubMed Central

Mohammadizadeh, Mehri

2015-01-01

Summary Strawberries have a very short post-harvest life mostly due to their relatively high water content, intense metabolic activity and susceptibility to microbial rot. Antimicrobial low-density polyethylene nanocomposite films containing ZnO nanoparticles at different mass fractions were prepared by melt mixing and followed by compression moulding using a hot press machine. Fresh strawberries were packed in nanocomposite films and stored at 4 °C. Their microbial stability, ascorbic acid content and titratable acidity were evaluated after 0, 4, 8, 12 and 16 days of storage. Microbial growth rate was significantly reduced up to 16 days as a result of the use of nanocomposite packaging material containing ZnO nanoparticles. By increasing the ZnO nanoparticle mass fraction to 5%, the antimicrobial activity of the film increased. All packages containing the ZnO nanoparticles kept the microbial load of fresh strawberries below the level that affects shelf life (5 log CFU/g) up to 16 days. The lowest degradation of ascorbic acid content (6.55 mg per 100 g), and loss of acidity (0.68%) were observed in packages containing 3% of ZnO nanoparticles with 10% polyethylene-grafted maleic anhydride. PMID:27904384

Preparation and Application of LDPE/ZnO Nanocomposites for Extending Shelf Life of Fresh Strawberries.

PubMed

Emamifar, Aryou; Mohammadizadeh, Mehri

2015-12-01

Strawberries have a very short post-harvest life mostly due to their relatively high water content, intense metabolic activity and susceptibility to microbial rot. Antimicrobial low-density polyethylene nanocomposite films containing ZnO nanoparticles at different mass fractions were prepared by melt mixing and followed by compression moulding using a hot press machine. Fresh strawberries were packed in nanocomposite films and stored at 4 °C. Their microbial stability, ascorbic acid content and titratable acidity were evaluated after 0, 4, 8, 12 and 16 days of storage. Microbial growth rate was significantly reduced up to 16 days as a result of the use of nanocomposite packaging material containing ZnO nanoparticles. By increasing the ZnO nanoparticle mass fraction to 5%, the antimicrobial activity of the film increased. All packages containing the ZnO nanoparticles kept the microbial load of fresh strawberries below the level that affects shelf life (5 log CFU/g) up to 16 days. The lowest degradation of ascorbic acid content (6.55 mg per 100 g), and loss of acidity (0.68%) were observed in packages containing 3% of ZnO nanoparticles with 10% polyethylene-grafted maleic anhydride.

Energetic differences between bacterioplankton trophic groups and coral reef resistance

PubMed Central

McDole Somera, Tracey; Bailey, Barbara; Barott, Katie; Grasis, Juris; Hatay, Mark; Hilton, Brett J.; Hisakawa, Nao; Nosrat, Bahador; Nulton, James; Silveira, Cynthia B.; Sullivan, Chris; Brainard, Russell E.; Rohwer, Forest

2016-01-01

Coral reefs are among the most productive and diverse marine ecosystems on the Earth. They are also particularly sensitive to changing energetic requirements by different trophic levels. Microbialization specifically refers to the increase in the energetic metabolic demands of microbes relative to macrobes and is significantly correlated with increasing human influence on coral reefs. In this study, metabolic theory of ecology is used to quantify the relative contributions of two broad bacterioplankton groups, autotrophs and heterotrophs, to energy flux on 27 Pacific coral reef ecosystems experiencing human impact to varying degrees. The effective activation energy required for photosynthesis is lower than the average energy of activation for the biochemical reactions of the Krebs cycle, and changes in the proportional abundance of these two groups can greatly affect rates of energy and materials cycling. We show that reef-water communities with a higher proportional abundance of microbial autotrophs expend more metabolic energy per gram of microbial biomass. Increased energy and materials flux through fast energy channels (i.e. water-column associated microbial autotrophs) may dampen the detrimental effects of increased heterotrophic loads (e.g. coral disease) on coral reef systems experiencing anthropogenic disturbance. PMID:27097927

Bacterial Exchange in Household Washing Machines.

PubMed

Callewaert, Chris; Van Nevel, Sam; Kerckhof, Frederiek-Maarten; Granitsiotis, Michael S; Boon, Nico

2015-01-01

Household washing machines (WMs) launder soiled clothes and textiles, but do not sterilize them. We investigated the microbial exchange occurring in five household WMs. Samples from a new cotton T-shirt were laundered together with a normal laundry load. Analyses were performed on the influent water and the ingoing cotton samples, as well as the greywater and the washed cotton samples. The number of living bacteria was generally not lower in the WM effluent water as compared to the influent water. The laundering process caused a microbial exchange of influent water bacteria, skin-, and clothes-related bacteria and biofilm-related bacteria in the WM. A variety of biofilm-producing bacteria were enriched in the effluent after laundering, although their presence in the cotton sample was low. Nearly all bacterial genera detected on the initial cotton sample were still present in the washed cotton samples. A selection for typical skin- and clothes-related microbial species occurred in the cotton samples after laundering. Accordingly, malodour-causing microbial species might be further distributed to other clothes. The bacteria on the ingoing textiles contributed for a large part to the microbiome found in the textiles after laundering.

Energetic differences between bacterioplankton trophic groups and coral reef resistance.

PubMed

McDole Somera, Tracey; Bailey, Barbara; Barott, Katie; Grasis, Juris; Hatay, Mark; Hilton, Brett J; Hisakawa, Nao; Nosrat, Bahador; Nulton, James; Silveira, Cynthia B; Sullivan, Chris; Brainard, Russell E; Rohwer, Forest

2016-04-27

Coral reefs are among the most productive and diverse marine ecosystems on the Earth. They are also particularly sensitive to changing energetic requirements by different trophic levels. Microbialization specifically refers to the increase in the energetic metabolic demands of microbes relative to macrobes and is significantly correlated with increasing human influence on coral reefs. In this study, metabolic theory of ecology is used to quantify the relative contributions of two broad bacterioplankton groups, autotrophs and heterotrophs, to energy flux on 27 Pacific coral reef ecosystems experiencing human impact to varying degrees. The effective activation energy required for photosynthesis is lower than the average energy of activation for the biochemical reactions of the Krebs cycle, and changes in the proportional abundance of these two groups can greatly affect rates of energy and materials cycling. We show that reef-water communities with a higher proportional abundance of microbial autotrophs expend more metabolic energy per gram of microbial biomass. Increased energy and materials flux through fast energy channels (i.e. water-column associated microbial autotrophs) may dampen the detrimental effects of increased heterotrophic loads (e.g. coral disease) on coral reef systems experiencing anthropogenic disturbance. © 2016 The Author(s).

Chlorhexidine salt-loaded polyurethane orthodontic chains: in vitro release and antibacterial activity studies.

PubMed

Padois, Karine; Bertholle, Valérie; Pirot, Fabrice; Hyunh, Truc Thanh Ngoc; Rossi, Alessandra; Colombo, Paolo; Falson, Françoise; Sonvico, Fabio

2012-12-01

The widespread use of indwelling medical devices has enormously increased the interest in materials incorporating antibiotics and antimicrobial agents as a means to prevent dangerous device-related infections. Recently, chlorhexidine-loaded polyurethane has been proposed as a material suitable for the production of devices which are able to resist microbial contamination. The aim of the present study was to characterize the in vitro release of chlorhexidine from new polymeric orthodontic chains realized with polyurethane loaded with two different chlorhexidine salts: chlorhexidine diacetate or chlorhexidine digluconate. The orthodontic chains constituted of three layers: a middle polyurethane layer loaded with chlorhexidine salt inserted between two layers of unloaded polymer. In vitro release of chlorhexidine diacetate and digluconate from orthodontic chains loaded with 10% or 20% (w/w) chlorhexidine salt was sustained for 42 days and followed Fickian diffusion. The drug diffusion through the polyurethane was found to be dependent not only on chlorhexidine loading, but also on the type of chlorhexidine salt. The antibacterial activity of 0.2% (w/w) chlorhexidine diacetate-loaded orthodontic chain was successfully tested towards clinically isolated biofilm forming ica-positive Staphylococcus epidermidis via agar diffusion test. In conclusion, the chlorhexidine salt-loaded chains could provide an innovative approach in the prevention of oral infections related to the use of orthodontic devices.

Effect of Organic Dust Exposure on Pulmonary Functions in Workers of Vegetable Market with Special Reference to its Microbial Content.

PubMed

Goel, Arun; Omar, Balram Ji; Kathrotia, Rajesh; Patil, Prashant M; Mittal, Sunita

2018-01-01

Wholesale vegetable market is a rich source of generation of organic dust as loads of fruits and vegetables are loaded and unloaded here daily. Thus, regular workers are exposed to this organic dust for a considerable period of time depending on their work schedule. This study was planned to determine the microbial status of organic dust and to explore its association with pulmonary functions in the workers of wholesale vegetable market in Rishikesh. It was a cross-sectional exploratory/observational study. Thirty-five apparently healthy adult males were selected from vegetable market having no history of any chronic illness. Smokers and alcoholic were excluded from the study. The same number of age- and sex-matched controls with the same exclusion criteria were recruited from workers not working in the vegetable market and also not exposed to any other kinds of organic dust. Microbial culture of air in the vegetable market was done. It was compared with the microbial status of air in the working place of controls. Pulmonary functions of all the workers were performed with the help of digital spirometer (Helios 401). Bacterial and fungal concentration was found to be significantly higher in the air of vegetable market as compared to air in the workplace of controls (such as coagulase-negative staphylococci >25 colony-forming unit (CFU) at incubation temperature vs. 10-12 CFU at incubation temperature, significant growth of Mucor , Aspergillus niger , and Candida nonalbicans in vegetable market as compared to workplace of controls). Pulmonary function parameters (percentage forced expiratory volume in 1 st s (FEV 1 ), percentage predicted forced expiratory flow in mid-half of expiration, and FEV 1 ) of workers exposed to organic dust in vegetable market were also significantly lower ( P < 0.05). Exposure of organic dust is associated with compromised pulmonary functions and there is a need of formulation of safety guidelines.

Characterization of microbial and chemical composition of shuttle wet waste with permanent gas and volatile organic compound analyses

NASA Astrophysics Data System (ADS)

Peterson, B. V.; Hummerick, M.; Roberts, M. S.; Krumins, V.; Kish, A. L.; Garland, J. L.; Maxwell, S.; Mills, A.

2004-01-01

Solid-waste treatment in space for Advanced Life Support, ALS, applications requires that the material can be safely processed and stored in a confined environment. Many solid-wastes are not stable because they are wet (40-90% moisture) and contain levels of soluble organic compounds that can contribute to the growth of undesirable microorganisms with concomitant production of noxious odors. In the absence of integrated Advanced Life Support systems on orbit, permanent gas, trace volatile organic and microbiological analyses were performed on crew refuse returned from the volume F "wet" trash of three consecutive Shuttle missions (STS-105, 109, and 110). These analyses were designed to characterize the short-term biological stability of the material and assess potential crew risks resulting from microbial decay processes during storage. Waste samples were collected post-orbiter landing and sorted into packaging material, food waste, toilet waste, and bulk liquid fractions deposited during flight in the volume F container. Aerobic and anaerobic microbial loads were determined in each fraction by cultivation on R2A and by acridine orange direct count (AODC). Dry and ash weights were performed to determine both water and organic content of the materials. Experiments to determine the aerobic and anaerobic biostability of refuse stored for varying periods of time were performed by on-line monitoring of CO 2 and laboratory analysis for production of hydrogen sulfide and methane. Volatile organic compounds and permanent gases were analyzed using EPA Method TO15 by USEPA et al. [EPA Method TO15, The Determination of Volatile Organic Compounds (VOCs) in Ambient Air using SUMMA, Passivated Canister Sampling and Gas Chromatographic Analysis, 1999] with gas chromatography/mass spectrometry and by gas chromatography with selective detectors. These baseline measures of waste stream content, labile organics, and microbial load in the volume F Shuttle trash provide data for waste subsystem analysis and atmospheric management within the ALS Project.

Microneedle Arrays Allow Lower Microbial Penetration Than Hypodermic Needles In Vitro

PubMed Central

Donnelly, Ryan F.; Singh, Thakur Raghu Raj; Tunney, Michael M.; Morrow, Desmond I. J.; McCarron, Paul A.; O’Mahony, Conor; Woolfson, A. David

2010-01-01

Methods In this study we determined, for the first time, the ability of microorganisms to traverse microneedle-induced holes using two different in vitro models. Results When employing Silescol® membranes, the numbers of Candida albicans, Pseudomonas aeruginosa and Staphylococcus epidermidis crossing the membranes were an order of magnitude lower when the membranes were punctured by microneedles rather than a 21G hypodermic needle. Apart from the movement of C. albicans across hypodermic needle-punctured membranes, where 40.2% of the microbial load on control membranes permeated the barrier over 24 h, the numbers of permeating microorganisms was less than 5% of the original microbial load on control membranes. Experiments employing excised porcine skin and radiolabelled microorganisms showed that the numbers of microorganisms penetrating skin beyond the stratum corneum were approximately an order of magnitude greater than the numbers crossing Silescol® membranes in the corresponding experiments. Approximately 103cfu of each microorganism adhered to hypodermic needles during insertion. The numbers of microorganisms adhering to MN arrays were an order of magnitude higher in each case. Conclusion We have shown here that microneedle puncture resulted in significantly less microbial penetration than did hypodermic needle puncture and that no microorganisms crossed the viable epidermis in microneedle—punctured skin, in contrast to needle-punctured skin. Given the antimicrobial properties of skin, it is, therefore, likely that application of microneedle arrays to skin in an appropriate manner would not cause either local or systemic infection in normal circumstances in immune-competent patients. In supporting widespread clinical use of microneedle-based delivery systems, appropriate animal studies are now needed to conclusively demonstrate this in vivo. Safety in patients will be enhanced by aseptic or sterile manufacture and by fabricating microneedles from self-disabling materials (e.g. dissolving or biodegradable polymers) to prevent inappropriate or accidental reuse. PMID:19756972

Comparison of cleaning efficacy between in-use disinfectant and electrolysed water in an English residential care home.

PubMed

Meakin, N S; Bowman, C; Lewis, M R; Dancer, S J

2012-02-01

Infection control in hospitals and care homes remains a key issue. They are regularly inspected regarding standards of hygiene, but visual assessment does not necessarily correlate with microbial cleanliness. Pathogens can persist in the inanimate environment for extended periods of time. This prospective study compared the effectiveness of a novel sanitizer containing electrolysed water, in which the active ingredient is stabilized hypochlorous acid (Aqualution™), with the effectiveness of the quaternary ammonium disinfectant in current use for microbial removal from hand-touch surfaces in a care home. The study had a two-period crossover design. Five surfaces were cleaned daily over a four-week period, with screening swabs taken before and after cleaning. Swabs were cultured in order to compare levels of surface microbial contamination [colony-forming units (cfu)/cm(2)] before and after cleaning with each product. Cleaning with electrolysed water reduced the mean surface bacterial load from 2.6 [interquartile range (IQR) 0.30-30.40] cfu/cm(2) to 0.10 (IQR 0.10-1.40) cfu/cm(2) [mean log(10) reduction factor 1.042, 95% confidence interval (CI) 0.79-1.30]. Cleaning with the in-use quaternary ammonium disinfectant increased the bacterial load from 0.90 (IQR 0.10-8.50) cfu/cm(2) to 93.30 (IQR 9.85-363.65) cfu/cm(2) (mean log(10) reduction -1.499, 95% CI -1.87 to -1.12) (P < 0.0001). Using two proposed benchmark standards for surface microbial levels in hospitals, electrolysed water resulted in a higher 'pass rate' than the in-use quaternary ammonium disinfectant (80-86% vs 15-21%, P < 0.0001). Electrolysed water exerts a more effective bacterial kill than the in-use quaternary ammonium disinfectant, which suggests that it may be useful as a surface sanitizer in environments such as care homes. Copyright © 2011 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Characterization of microbial and chemical composition of shuttle wet waste with permanent gas and volatile organic compound analyses

NASA Technical Reports Server (NTRS)

Peterson, B. V.; Hummerick, M.; Roberts, M. S.; Krumins, V.; Kish, A. L.; Garland, J. L.; Maxwell, S.; Mills, A.

2004-01-01

Solid-waste treatment in space for Advanced Life Support, ALS, applications requires that the material can be safely processed and stored in a confined environment. Many solid-wastes are not stable because they are wet (40-90% moisture) and contain levels of soluble organic compounds that can contribute to the growth of undesirable microorganisms with concomitant production of noxious odors. In the absence of integrated Advanced Life Support systems on orbit, permanent gas, trace volatile organic and microbiological analyses were performed on crew refuse returned from the volume F "wet" trash of three consecutive Shuttle missions (STS-105, 109, and 110). These analyses were designed to characterize the short-term biological stability of the material and assess potential crew risks resulting from microbial decay processes during storage. Waste samples were collected post-orbiter landing and sorted into packaging material, food waste, toilet waste, and bulk liquid fractions deposited during flight in the volume F container. Aerobic and anaerobic microbial loads were determined in each fraction by cultivation on R2A and by acridine orange direct count (AODC). Dry and ash weights were performed to determine both water and organic content of the materials. Experiments to determine the aerobic and anaerobic biostability of refuse stored for varying periods of time were performed by on-line monitoring of CO2 and laboratory analysis for production of hydrogen sulfide and methane. Volatile organic compounds and permanent gases were analyzed using EPA Method TO15 by USEPA et al. [EPA Method TO15, The Determination of Volatile Organic Compounds (VOCs) in Ambient Air using SUMMA, Passivated Canister Sampling and Gas Chromatographic Analysis,1999] with gas chromatography/mass spectrometry and by gas chromatography with selective detectors. These baseline measures of waste stream content, labile organics, and microbial load in the volume F Shuttle trash provide data for waste subsystem analysis and atmospheric management within the ALS Project. Published by Elsevier Ltd on behalf of COSPAR.

Internalisation of microbes in vegetables: microbial load of Ghanaian vegetables and the relationship with different water sources of irrigation.

PubMed

Donkor, Eric S; Lanyo, R; Kayang, Boniface B; Quaye, Jonathan; Edoh, Dominic A

2010-09-01

The occurrence of pathogens in the internal parts of vegetables is usually associated with irrigation water or contaminated soil and could pose risk to consumers as the internalised pathogens are unaffected by external washing. This study was carried out to assess the rate of internalisation of microbes in common Ghanaian vegetables. Standard microbiological methods were employed in microbial enumeration of vegetables collected at the market and farm levels, as well as irrigation water and soil samples. The overall mean counts of vegetables were 4.0 x 10(3) cfu g(-1); 8.1 x 10(2) cfu g(-1); 2.0 x 10(2) cfu g(-1); 3.5 x 10(2) cfu g(-1) for total bacteria, coliform counts, faecal coliform counts and yeast counts, respectively. The rate of internalisation of coliforms in vegetables irrigated with stream/well water was 2.7 times higher than those irrigated with pipe water. The mean coliform counts (4.7 x 10(7) cfu g(-1)) and faecal coliform counts (1.8 x 10(6) cfu g(-1)) of soil samples were similar to those of stream water suggesting both sources exerted similar contamination rates on the vegetables. Generally, there were no significant variations between the rates of internalisation of microbes at the market and farm levels at p < 05, indicating that internalisation of microbes in the vegetables mainly occurred at the farm level. The study has shown that microbial contamination of vegetables in Ghana is not limited to the external surface, but internal vegetable parts could harbour high microbial loads and pose risk to consumers. Safety practices associated with the commodity should therefore not be limited to external washing only. There is the additional need of heating vegetables to eliminate microbes both externally and internally before consumption.

Characterization of microbial and chemical composition of shuttle wet waste with permanent gas and volatile organic compound analyses.

PubMed

Peterson, B V; Hummerick, M; Roberts, M S; Krumins, V; Kish, A L; Garland, J L; Maxwell, S; Mills, A

2004-01-01

Solid-waste treatment in space for Advanced Life Support, ALS, applications requires that the material can be safely processed and stored in a confined environment. Many solid-wastes are not stable because they are wet (40-90% moisture) and contain levels of soluble organic compounds that can contribute to the growth of undesirable microorganisms with concomitant production of noxious odors. In the absence of integrated Advanced Life Support systems on orbit, permanent gas, trace volatile organic and microbiological analyses were performed on crew refuse returned from the volume F "wet" trash of three consecutive Shuttle missions (STS-105, 109, and 110). These analyses were designed to characterize the short-term biological stability of the material and assess potential crew risks resulting from microbial decay processes during storage. Waste samples were collected post-orbiter landing and sorted into packaging material, food waste, toilet waste, and bulk liquid fractions deposited during flight in the volume F container. Aerobic and anaerobic microbial loads were determined in each fraction by cultivation on R2A and by acridine orange direct count (AODC). Dry and ash weights were performed to determine both water and organic content of the materials. Experiments to determine the aerobic and anaerobic biostability of refuse stored for varying periods of time were performed by on-line monitoring of CO2 and laboratory analysis for production of hydrogen sulfide and methane. Volatile organic compounds and permanent gases were analyzed using EPA Method TO15 by USEPA et al. [EPA Method TO15, The Determination of Volatile Organic Compounds (VOCs) in Ambient Air using SUMMA, Passivated Canister Sampling and Gas Chromatographic Analysis,1999] with gas chromatography/mass spectrometry and by gas chromatography with selective detectors. These baseline measures of waste stream content, labile organics, and microbial load in the volume F Shuttle trash provide data for waste subsystem analysis and atmospheric management within the ALS Project. Published by Elsevier Ltd on behalf of COSPAR.

Land application of tylosin and chlortetracycline swine manure: Impacts to soil nutrients and soil microbial community structure.

PubMed

Stone, James J; Dreis, Erin K; Lupo, Christopher D; Clay, Sharon A

2011-01-01

The land application of aged chortetracycle (CTC) and tylosin-containing swine manure was investigated to determine associated impacts to soil microbial respiration, nutrient (phosphorus, ammonium, nitrate) cycling, and soil microbial community structure under laboratory conditions. Two silty clay loam soils common to southeastern South Dakota were used. Aerobic soil respiration results using batch reactors containing a soil-manure mixture showed that interactions between soil, native soil microbial populations, and antimicrobials influenced CO(2) generation. The aged tylosin treatment resulted in the greatest degree of CO(2) inhibition, while the aged CTC treatment was similar to the no-antimicrobial treatment. For soil columns in which manure was applied at a one-time agronomic loading rate, there was no significant difference in soil-P behavior between either aged CTC or tylosin and the no-antimicrobial treatment. For soil-nitrogen (ammonium and nitrate), the aged CTC treatment resulted in rapid ammonium accumulation at the deeper 40cm soil column depth, while nitrate production was minimal. The aged CTC treatment microbial community structure was different than the no-antimicrobial treatment, where amines/amide and carbohydrate chemical guilds utilization profile were low. The aged tylosin treatment also resulted in ammonium accumulation at 40 cm column depth, however nitrate accumulation also occurred concurrently at 10 cm. The microbial community structure for the aged tylosin was also significantly different than the no-antimicrobial treatment, with a higher degree of amines/amides and carbohydrate chemical guild utilization compared to the no-antimicrobial treatment. Study results suggest that land application of CTC and tylosin-containing manure appears to fundamentally change microbial-mediated nitrogen behavior within soil A horizons.

Modelling the impact of future socio-economic and climate change scenarios on river microbial water quality.

PubMed

Islam, M M Majedul; Iqbal, Muhammad Shahid; Leemans, Rik; Hofstra, Nynke

2018-03-01

Microbial surface water quality is important, as it is related to health risk when the population is exposed through drinking, recreation or consumption of irrigated vegetables. The microbial surface water quality is expected to change with socio-economic development and climate change. This study explores the combined impacts of future socio-economic and climate change scenarios on microbial water quality using a coupled hydrodynamic and water quality model (MIKE21FM-ECOLab). The model was applied to simulate the baseline (2014-2015) and future (2040s and 2090s) faecal indicator bacteria (FIB: E. coli and enterococci) concentrations in the Betna river in Bangladesh. The scenarios comprise changes in socio-economic variables (e.g. population, urbanization, land use, sanitation and sewage treatment) and climate variables (temperature, precipitation and sea-level rise). Scenarios have been developed building on the most recent Shared Socio-economic Pathways: SSP1 and SSP3 and Representative Concentration Pathways: RCP4.5 and RCP8.5 in a matrix. An uncontrolled future results in a deterioration of the microbial water quality (+75% by the 2090s) due to socio-economic changes, such as higher population growth, and changes in rainfall patterns. However, microbial water quality improves under a sustainable scenario with improved sewage treatment (-98% by the 2090s). Contaminant loads were more influenced by changes in socio-economic factors than by climatic change. To our knowledge, this is the first study that combines climate change and socio-economic development scenarios to simulate the future microbial water quality of a river. This approach can also be used to assess future consequences for health risks. Copyright © 2017 The Authors. Published by Elsevier GmbH.. All rights reserved.

The impact of post-fire salvage logging on microbial nitrogen cyclers in Mediterranean forest soil.

PubMed

Pereg, Lily; Mataix-Solera, Jorge; McMillan, Mary; García-Orenes, Fuensanta

2018-04-01

Forest fires are a regular occurrence in the Mediterranean basin. High severity fires and post-fire management can affect biological, chemical and physical properties of soil, including the composition and abundance of soil microbial communities. Salvage logging is a post-fire management strategy, which involves the removal of burnt wood from land after a fire. The main objective of this work was to evaluate the impact of post-fire salvage logging and microaggregation on soil microbial communities, specifically on the abundance of nitrogen cyclers and, thus, the potential of the soil for microbial nitrogen cycling. The abundance of nitrogen cyclers was assessed by quantification of microbial nitrogen cycling genes in soil DNA, including nifH (involved in nitrogen fixation), nirS/K and nosZ (involved in denitrification), amoA-B and amoA-Arch (involved in bacterial and archaeal nitrification, respectively). It was demonstrated that salvage logging reduced bacterial load post-fire when compared to tree retention control and resulted in significant changes to the abundance of functional bacteria involved in nitrogen cycling. Microbial gene pools involved in various stages of the nitrogen cycle were larger in control soil than in soil subjected to post-fire salvage logging and were significantly correlated with organic matter, available phosphorous, nitrogen and aggregate stability. The microaggregate fraction of the soil, which has been associated with greater organic carbon, was shown to be a hotspot for nitrogen cyclers particularly under salvage logging. The impact of post-fire management strategies on soil microbial communities needs to be considered in relation to maintaining ecosystem productivity, resilience and potential impact on climate change. Copyright © 2017 Elsevier B.V. All rights reserved.

Functionally redundant but dissimilar microbial communities within biogas reactors treating maize silage in co-fermentation with sugar beet silage

PubMed Central

Langer, Susanne G; Ahmed, Sharif; Einfalt, Daniel; Bengelsdorf, Frank R; Kazda, Marian

2015-01-01

Numerous observations indicate a high flexibility of microbial communities in different biogas reactors during anaerobic digestion. Here, we describe the functional redundancy and structural changes of involved microbial communities in four lab-scale continuously stirred tank reactors (CSTRs, 39°C, 12 L volume) supplied with different mixtures of maize silage (MS) and sugar beet silage (SBS) over 80 days. Continuously stirred tank reactors were fed with mixtures of MS and SBS in volatile solid ratios of 1:0 (Continuous Fermenter (CF) 1), 6:1 (CF2), 3:1 (CF3), 1:3 (CF4) with equal organic loading rates (OLR 1.25 kgVS m−3 d−1) and showed similar biogas production rates in all reactors. The compositions of bacterial and archaeal communities were analysed by 454 amplicon sequencing approach based on 16S rRNA genes. Both bacterial and archaeal communities shifted with increasing amounts of SBS. Especially pronounced were changes in the archaeal composition towards Methanosarcina with increasing proportion of SBS, while Methanosaeta declined simultaneously. Compositional shifts within the microbial communities did not influence the respective biogas production rates indicating that these communities adapted to environmental conditions induced by different feedstock mixtures. The diverse microbial communities optimized their metabolism in a way that ensured efficient biogas production. PMID:26200922

Review of Microbial Responses to Abiotic Environmental Factors in the Context of the Proposed Yucca Mountain Repository

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meike, A.; Stroes-Gascoyne, S.

2000-08-01

A workshop on Microbial Activities at Yucca Mountain (May 1995, Lafayette, CA) was held with the intention to compile information on all pertinent aspects of microbial activity for application to a potential repository at Yucca Mountain. The findings of this workshop set off a number of efforts intended to eventually incorporate the impacts of microbial behavior into performance assessment models. One effort was to expand an existing modeling approach to include the distinctive characteristics of a repository at Yucca Mountain (e.g., unsaturated conditions and a significant thermal load). At the same time, a number of experimental studies were initiated asmore » well as a compilation of relevant literature to more thoroughly study the physical, chemical and biological parameters that would affect microbial activity under Yucca Mountain-like conditions. This literature search (completed in 1996) is the subject of the present document. The collected literature can be divided into four categories: (1) abiotic factors, (2) community dynamics and in-situ considerations, (3) nutrient considerations and (4) transport of radionuclides. The complete bibliography represents a considerable resource, but is too large to be discussed in one document. Therefore, the present report focuses on the first category, abiotic factors, and a discussion of these factors in order to facilitate the development of a model for Yucca Mountain.« less

A geographical information system (GIS) as a tool for microbial risk assessment in catchment areas of drinking water reservoirs.

PubMed

Kistemann, T; Dangendorf, F; Exner, M

2001-03-01

The main tributaries of three drinking water reservoirs of Northrhine-Westfalia (Germany) were monitored within a 14-month period mainly for bacterial and parasitic contamination. In this context a detailed geo-ecological characterisation within the differing catchment areas was carried out to reveal a reliable informational basis for tracing back the origin of microbial loads present in the watercourses. To realise a microbial risk assessing geo-ecological information system (MRA-GIS), a Geographical Information System (GIS) has been implemented for the study areas. The results of the microbiological investigations of the watercourses showed an input of pathogens into all three of the tributaries. It could be demonstrated that the use of MRA-GIS database and some GIS-techniques substantially support the spatial analysis of the microbial contamination patterns. From the hygienic point of view, it is of the utmost importance to protect catchment areas of surface water reservoirs from microbial contamination stemming from human activities and animal sources. This constitutes essential part of the multi-barrier concept which stresses the importance of reducing diffuse and point pollution in catchment areas of water resources intended for human consumption. MRA-GIS proves to be helpful to manage multi-barrier water protection in catchment areas and ideally assists the application of the HACCP concept on drinking water production.

Fate of Cd during microbial Fe(III) mineral reduction by a novel and Cd-tolerant Geobacter species.

PubMed

Muehe, E Marie; Obst, Martin; Hitchcock, Adam; Tyliszczak, Tolek; Behrens, Sebastian; Schröder, Christian; Byrne, James M; Michel, F Marc; Krämer, Ute; Kappler, Andreas

2013-12-17

Fe(III) (oxyhydr)oxides affect the mobility of contaminants in the environment by providing reactive surfaces for sorption. This includes the toxic metal cadmium (Cd), which prevails in agricultural soils and is taken up by crops. Fe(III)-reducing bacteria can mobilize such contaminants by Fe(III) mineral dissolution or immobilize them by sorption to or coprecipitation with secondary Fe minerals. To date, not much is known about the fate of Fe(III) mineral-associated Cd during microbial Fe(III) reduction. Here, we describe the isolation of a new Geobacter sp. strain Cd1 from a Cd-contaminated field site, where the strain accounts for 10(4) cells g(-1) dry soil. Strain Cd1 reduces the poorly crystalline Fe(III) oxyhydroxide ferrihydrite in the presence of at least up to 112 mg Cd L(-1). During initial microbial reduction of Cd-loaded ferrihydrite, sorbed Cd was mobilized. However, during continuous microbial Fe(III) reduction, Cd was immobilized by sorption to and/or coprecipitation within newly formed secondary minerals that contained Ca, Fe, and carbonate, implying the formation of an otavite-siderite-calcite (CdCO3-FeCO3-CaCO3) mixed mineral phase. Our data shows that microbially mediated turnover of Fe minerals affects the mobility of Cd in soils, potentially altering the dynamics of Cd uptake into food or phyto-remediating plants.

Understanding microbial ecology can help improve biogas production in AD.

PubMed

Ferguson, Robert M W; Coulon, Frédéric; Villa, Raffaella

2018-06-16

454-Pyrosequencing and lipid fingerprinting were used to link anaerobic digestion (AD) process parameters (pH, alkalinity, volatile fatty acids (VFAs), biogas production and methane content) with the reactor microbial community structure and composition. AD microbial communities underwent stress conditions after changes in organic loading rate and digestion substrates. 454-Pyrosequencing analysis showed that, irrespectively of the substrate digested, methane content and pH were always significantly, and positively, correlated with community evenness. In AD, microbial communities with more even distributions of diversity are able to use parallel metabolic pathways and have greater functional stability; hence, they are capable of adapting and responding to disturbances. In all reactors, a decrease in methane content to <30% was always correlated with a 50% increase of Firmicutes sequences (particularly in operational taxonomic units (OTUs) related to Ruminococcaceae and Veillonellaceae). Whereas digesters producing higher methane content (above 60%), contained a high number of sequences related to Synergistetes and unidentified bacterial OTUs. Finally, lipid fingerprinting demonstrated that, under stress, the decrease in archaeal biomass was higher than the bacterial one, and that archaeal Phospholipid etherlipids (PLEL) levels were correlated to reactor performances. These results demonstrate that, across a number of parameters such as lipids, alpha and beta diversity, and OTUs, knowledge of the microbial community structure can be used to predict, monitor, or optimise AD performance. Copyright © 2018 Elsevier B.V. All rights reserved.

Everglqades Mercury: Biogeochemistry, Modeling, and Possible Mitigation

NASA Astrophysics Data System (ADS)

Orem, W. H.

2015-12-01

In the 1980s high levels of methylmercury (MeHg) were found in fish and other biota in the Florida Everglades, prompting fish consumption advisories. As part of Everglades restoration efforts Federal and State Agencies initiated a research program to study the underlying causes of the MeHg contamination. As part of this multi-agency effort, the U.S. Geological Survey developed the ACME (Aquatic Cycling of Mercury in the Everglades) project to examine the underlying biogeochemical factors controlling MeHg production and bioaccumulation in the ecosystem. Field studies by ACME and others identified the many factors impacting MeHg production in the Everglades. Thes factors include: high mercury deposition, large wetland area with organic-rich anaerobic soil, high sulfate loading in surface runoff, circumneutral pH, and high dissolved organic matter (DOM) content. Florida Department of Environmental Protection efforts that reduced local mercury emissions by 90%, produced only a small reduction in mercury deposition on the Everglades, suggesting that most Hg deposited on the ecosystem originates from distant sources, and beyond the reach of regulators. ACME studies demonstrated that high sulfate loading to the Everglades comes from discharge of canal water originating in the Everglades Agricultural Area (EAA). The use of sulfur in agriculture and soil oxidation in the EAA have been shown to be the principal sources of the sulfate loading. Sulfate entering the ecosystem drives microbial sulfate reduction and MeHg production, but inhibition of MeHg production by sulfide (a byproduct of microbial sulfate reduction) makes the biogeochemistry complex. Laboratory microcosm and field mesocosm experiments by ACME helped define the complexity of the sulfur/MeHg biogeochemistry, and demonstrated the key role of dissolved organic matter in MeHg production. A conceptual model was developed that relates MeHg production to sulfate loading, DOM, and soil composition. This conceptual model was then used in the development of a mathematical model that relates how changes in sulfate loading affect MeHg production in the ecosystem. This model is currently being used to examine how limits on sulfate loading to the ecosystem could be used as a mitigation strategy to control MeHg production and levels of MeHg in Everglades biota.

Overcoming organic and nitrogen overload in thermophilic anaerobic digestion of pig slurry by coupling a microbial electrolysis cell.

PubMed

Cerrillo, Míriam; Viñas, Marc; Bonmatí, August

2016-09-01

The combination of the anaerobic digestion (AD) process with a microbial electrolysis cell (MEC) coupled to an ammonia stripping unit as a post-treatment was assessed both in series operation, to improve the quality of the effluent, and in loop configuration recirculating the effluent, to increase the AD robustness. The MEC allowed maintaining the chemical oxygen demand removal of the whole system of 46±5% despite the AD destabilization after doubling the organic and nitrogen loads, while recovering 40±3% of ammonia. The AD-MEC system, in loop configuration, helped to recover the AD (55% increase in methane productivity) and attained a more stable and robust operation. The microbial population assessment revealed an enhancement of AD methanogenic archaea numbers and a shift in eubacterial population. The AD-MEC combined system is a promising strategy for stabilizing AD against organic and nitrogen overloads, while improving the quality of the effluent and recovering nutrients for their reutilization. Copyright © 2016 Elsevier Ltd. All rights reserved.

Microbial quality evaluation and effective decontamination of nutraceutically valued lotus seeds by electron beams and gamma irradiation

NASA Astrophysics Data System (ADS)

Bhat, Rajeev; Sridhar, K. R.; Karim, A. A.

2010-09-01

Lotus seeds are nutraceutically valued natural plant produce, which succumbs to microbial contamination, predominantly to toxigenic moulds. Results of the present study revealed seed coat portion to harbor higher proportion of microbial load, particularly fungi than cotyledon portion. Among the mycotoxins analyzed, aflatoxins (B 1, B 2, G 1 and G 2) were below detectable limits, while the seeds were devoid of Ochratoxin-A (OTA). Application of different doses of electron beam and gamma irradiation (0, 2.5, 5, 7.5, 10, 15 and 30 kGy) for decontamination purpose revealed significant dose-dependent decrease in the fungal contaminants ( P<0.05). However, the contaminant yeasts could survive up to 10 kGy dose, which could be completely eliminated at 15 kGy. From the results obtained, a dose range between 10 and 15 kGy is recommended for complete decontamination, as these doses have also been shown earlier to have minimal effects on nutritional and functional properties of lotus seeds.

Design and application of a synthetic DNA standard for real-time PCR analysis of microbial communities in a biogas digester.

PubMed

May, T; Koch-Singenstreu, M; Ebling, J; Stantscheff, R; Müller, L; Jacobi, F; Polag, D; Keppler, F; König, H

2015-08-01

A synthetic DNA fragment containing primer binding sites for the quantification of ten different microbial groups was constructed and evaluated as a reliable enumeration standard for quantitative real-time PCR (qPCR) analyses. This approach has been exemplary verified for the quantification of several methanogenic orders and families in a series of samples drawn from a mesophilic biogas plant. Furthermore, the total amounts of bacteria as well as the number of sulfate-reducing and propionic acid bacteria as potential methanogenic interaction partners were successfully determined. The obtained results indicated a highly dynamic microbial community structure which was distinctly affected by the organic loading rate, the substrate selection, and the amount of free volatile fatty acids in the fermenter. Methanosarcinales was the most predominant methanogenic order during the 3 months of observation despite fluctuating process conditions. During all trials, the modified quantification standard indicated a maximum of reproducibility and efficiency, enabling this method to open up a wide range of novel application options.

Use of natural compounds to improve the microbial stability of Amaranth-based homemade fresh pasta.

PubMed

Del Nobile, M A; Di Benedetto, N; Suriano, N; Conte, A; Lamacchia, C; Corbo, M R; Sinigaglia, M

2009-04-01

A study on the use of natural antimicrobial compounds to improve the microbiological stability of refrigerated amaranth-based homemade fresh pasta is presented in this work. In particular, the antimicrobial activity of thymol, lemon extract, chitosan and grapefruit seed extract (GFSE) has been tested against mesophilic and psychrotrophic bacteria, total coliforms, Staphylococcus spp., yeasts and moulds. A sensory analysis on both fresh and cooked pasta was also run. Results suggest that chitosan and GFSE strongly increase the microbial acceptability limit of the investigated spoilage microorganisms, being the former the most effective. Thymol efficiently reduces the growth of mesophilic bacteria, psychrotrophic bacteria and Staphylococcus spp., whereas it does not affect, substantially, the growth cycle of total coliforms. Lemon extract is the less effective in preventing microbial growth. In fact, it is able to delay only total mesophilic and psychrotrophic bacterial evolution. From a sensorial point of view no significant differences were recorded between the control samples and all the types of loaded amaranth-based pasta.

Land cover and forest connectivity alter the interactions among host, pathogen and skin microbiome.

PubMed

Becker, C G; Longo, A V; Haddad, C F B; Zamudio, K R

2017-08-30

Deforestation has detrimental consequences on biodiversity, affecting species interactions at multiple scales. The associations among vertebrates, pathogens and their commensal/symbiotic microbial communities (i.e. microbiomes) have important downstream effects for biodiversity conservation, yet we know little about how deforestation contributes to changes in host microbial diversity and pathogen abundance. Here, we tested the effects of landcover, forest connectivity and infection by the chytrid fungus Batrachochytrium dendrobatidis ( Bd ) on amphibian skin bacterial diversity along deforestation gradients in Brazilian landscapes. If disturbance to natural habitat alters skin microbiomes as it does in vertebrate host communities, then we would expect higher host bacterial diversity in natural forest habitats. Bd infection loads are also often higher in these closed-canopy forests, which may in turn impact skin-associated bacterial communities. We found that forest corridors shaped composition of host skin microbiomes; high forest connectivity predicted greater similarity of skin bacterial communities among host populations. In addition, we found that host skin bacterial diversity and Bd loads increased towards natural vegetation. Because symbiotic bacteria can potentially buffer hosts from Bd infection, we also evaluated the bi-directional microbiome- Bd link but failed to find a significant effect of skin bacterial diversity reducing Bd infections. Although weak, we found support for Bd increasing bacterial diversity and/or for core bacteria dominance reducing Bd loads. Our research incorporates a critical element in the study of host microbiomes by linking environmental heterogeneity of landscapes to the host-pathogen-microbiome triangle. © 2017 The Author(s).

Molecular analysis of meso- and thermophilic microbiota associated with anaerobic biowaste degradation

PubMed Central

2012-01-01

Background Microbial anaerobic digestion (AD) is used as a waste treatment process to degrade complex organic compounds into methane. The archaeal and bacterial taxa involved in AD are well known, whereas composition of the fungal community in the process has been less studied. The present study aimed to reveal the composition of archaeal, bacterial and fungal communities in response to increasing organic loading in mesophilic and thermophilic AD processes by applying 454 amplicon sequencing technology. Furthermore, a DNA microarray method was evaluated in order to develop a tool for monitoring the microbiological status of AD. Results The 454 sequencing showed that the diversity and number of bacterial taxa decreased with increasing organic load, while archaeal i.e. methanogenic taxa remained more constant. The number and diversity of fungal taxa increased during the process and varied less in composition with process temperature than bacterial and archaeal taxa, even though the fungal diversity increased with temperature as well. Evaluation of the microarray using AD sample DNA showed correlation of signal intensities with sequence read numbers of corresponding target groups. The sensitivity of the test was found to be about 1%. Conclusions The fungal community survives in anoxic conditions and grows with increasing organic loading, suggesting that Fungi may contribute to the digestion by metabolising organic nutrients for bacterial and methanogenic groups. The microarray proof of principle tests suggest that the method has the potential for semiquantitative detection of target microbial groups given that comprehensive sequence data is available for probe design. PMID:22727142

Integrated analysis of water quality parameters for cost-effective faecal pollution management in river catchments.

PubMed

Nnane, Daniel Ekane; Ebdon, James Edward; Taylor, Huw David

2011-03-01

In many parts of the world, microbial contamination of surface waters used for drinking, recreation, and shellfishery remains a pervasive risk to human health, especially in Less Economically Developed Countries (LEDC). However, the capacity to provide effective management strategies to break the waterborne route to human infection is often thwarted by our inability to identify the source of microbial contamination. Microbial Source Tracking (MST) has potential to improve water quality management in complex river catchments that are either routinely, or intermittently contaminated by faecal material from one or more sources, by attributing faecal loads to their human or non-human sources, and thereby supporting more rational approaches to microbial risk assessment. The River Ouse catchment in southeast England (U.K.) was used as a model with which to investigate the integration and application of a novel and simple MST approach to monitor microbial water quality over one calendar year, thereby encompassing a range of meteorological conditions. A key objective of the work was to develop simple low-cost protocols that could be easily replicated. Bacteriophages (viruses) capable of infecting a human specific strain of Bacteroides GB-124, and their correlation with presumptive Escherichia coli, were used to distinguish sources of faecal pollution. The results reported here suggest that in this river catchment the principal source of faecal pollution in most instances was non-human in origin. During storm events, presumptive E. coli and presumptive intestinal enterococci levels were 1.1-1.2 logs higher than during dry weather conditions, and levels of the faecal indicator organisms (FIOs) were closely associated with increased turbidity levels (presumptive E. coli and turbidity, r = 0.43). Spatio-temporal variation in microbial water quality parameters was accounted for by three principal components (67.6%). Cluster Analysis, reduced the fourteen monitoring sites to six representative 'sentinel' sites. The correlation coefficient between presumptive E. coli and phages of Bacteroides GB-124 was very small (r = 0.05) whilst that between turbidity and suspended solids was high (r = 0.62). Variations in climate, animal and anthropogenic interferences were all, either directly or indirectly, related to faecal contamination. The findings show the importance of meteorological conditions, such as storm events, on microbial water quality, and suggest that any future increases in the frequency of storm events (associated with climate change) are likely to result in a greater incidence of FIO/pathogen loads. This low-cost approach could help to predict spatio-temporal 'hotspots' of elevated waterborne disease risk. The work also represents an important step towards integrating novel MST tools into river catchment modelling. Copyright © 2011 Elsevier Ltd. All rights reserved.

Spatially Oscillating Activity and Microbial Succession of Mercury-Reducing Biofilms in a Technical-Scale Bioremediation System

PubMed Central

von Canstein, Harald; Li, Ying; Leonhäuser, Johannes; Haase, Elke; Felske, Andreas; Deckwer, Wolf-Dieter; Wagner-Döbler, Irene

2002-01-01

Mercury-contaminated chemical wastewater of a mercury cell chloralkali plant was cleaned on site by a technical-scale bioremediation system. Microbial mercury reduction of soluble Hg(II) to precipitating Hg(0) decreased the mercury load of the wastewater during its flow through the bioremediation system by up to 99%. The system consisted of a packed-bed bioreactor, where most of the wastewater's mercury load was retained, and an activated carbon filter, where residual mercury was removed from the bioreactor effluent by both physical adsorption and biological reduction. In response to the oscillation of the mercury concentration in the bioreactor inflow, the zone of maximum mercury reduction oscillated regularly between the lower and the upper bioreactor horizons or the carbon filter. At low mercury concentrations, maximum mercury reduction occurred near the inflow at the bottom of the bioreactor. At high concentrations, the zone of maximum activity moved to the upper horizons. The composition of the bioreactor and carbon filter biofilms was investigated by 16S-23S ribosomal DNA intergenic spacer polymorphism analysis. Analysis of spatial biofilm variation showed an increasing microbial diversity along a gradient of decreasing mercury concentrations. Temporal analysis of the bioreactor community revealed a stable abundance of two prevalent strains and a succession of several invading mercury-resistant strains which was driven by the selection pressure of high mercury concentrations. In the activated carbon filter, a lower selection pressure permitted a steady increase in diversity during 240 days of operation and the establishment of one mercury-sensitive invader. PMID:11916716

VEGGIE Pillow Testing: Microbial Analysis of Cut-and-Come-Again Species Testing

NASA Technical Reports Server (NTRS)

Nguyen, Bao-Thang; Massa, Gioia D.; Hummerick, Mary E.; Wheeler, Raymond M.

2011-01-01

With NASA focused on researching and developing technology for deep space missions, the need for a reliable supplementary food source must also be considered. For the ISS, resupplying the food source is more practical and cost effect since the facility is in low Earth orbit. However, as NASA attempts to push the frontier in space, the costs and distance for resupply will surely increase. Plants would contribute to the proportion of food and reduce the dependency on food from Earth. In addition, plants would provide oxygen production, carbon dioxide removal, and psychological benefits. As a result, a vegetable production system, VEGGIE, was developed for NASA to produce salad crops with minimal resources and study the beneficial effects. The VEGGIE pillow is a single use bag for growing crops that is used with the VEGGIE hardware. The VEGGIE pillow was tested with four different species of plants with the cut-and-come-again harvest method to determine the greatest yield. Instead of harvesting the entire plant, the harvest consisted of cutting leaves to allow the plant to regrow leaves. The harvest methods included cutting the plants weekly, bi-weekly, and monthly. A fifth plant species, radishes, was also harvested and replanted. Microbial load analysis and an ANOVA significance test were utilized. The data suggest that the two Brassica plants have the greatest yields; however, the microbial load is also greatest for the two plants per gram of fresh weight. Furthermore, the results support the reuse of pillows for multiple harvests as shown by the replanted radishes.

A Year in the Life of a Contaminated Heater-Cooler Unit With Mycobacterium chimaera?

PubMed

Garvey, Mark I; Bradley, Craig W; Walker, Jimmy

2017-06-01

OBJECTIVE Heater-cooler units (HCUs) have been shown to be a source of Mycobacterium chimaera infections. For the past year, weekly water samples have been taken from HCUs used at University Hospitals Birmingham (UHB) NHS Foundation Trust. We report the microbial contamination of the HCUs over a year detailing the decontamination regimes applied at UHB to reduce the microbial load. DESIGN Observational study SETTING UHB is a tertiary referral teaching hospital in Birmingham, United Kingdom, that provides clinical services to nearly 1 million patients every year. The UHB Cardiac department is one of the largest in the United Kingdom and provides treatment for adult patients with a wide range of cardiac diseases. METHODS Water samples taken from HCUs used at UHB for cardiopulmonary bypass surgery were sampled over a year to determine the number of microorganisms by membrane filtration. Various decontamination processes were employed throughout the year. RESULTS Varying total viable counts containing a wide variety of microorganisms were obtained from water inside the HCUs. No M. chimaera were isolated after replacement of the HCU internal tubing. Stringent decontamination regimes resulted in degradation of the HCUs and increased TVCs after several months. CONCLUSION More work is required to ensure effective decontamination processes to reduce the microbial load within the HCUs. Our studies indicate that weekly water sampling for TVC will be required indefinitely to monitor the water quality in these units as well as regular replacement of the tubing to control the build-up of biofilm. Infect Control Hosp Epidemiol 2017;38:705-711.

GeoChip-based analysis of the microbial community functional structures in simultaneous desulfurization and denitrification process.

PubMed

Yu, Hao; Chen, Chuan; Ma, Jincai; Liu, Wenzong; Zhou, Jizhong; Lee, Duu-Jong; Ren, Nanqi; Wang, Aijie

2014-07-01

The elemental sulfur (S°) recovery was evaluated in the presence of nitrate in two development models of simultaneous desulfurization and denitrification (SDD) process. At the loading rates of 0.9 kg S/(m³·day) for sulfide and 0.4 kg N/(m³·day) for nitrate, S° conversion rate was 91.1% in denitrifying sulfide removal (DSR) model which was higher than in integrated simultaneous desulfurization and denitrification (ISDD) model (25.6%). A comprehensive analysis of functional diversity, structure and metabolic potential of microbial communities was examined in two models by using functional gene array (GeoChip 2.0). GeoChip data indicated that diversity indices, community structure, and abundance of functional genes were distinct between two models. Diversity indices (Simpson's diversity index (1/D) and Shannon-Weaver index (H')) of all detected genes showed that with elevated influent loading rate, the functional diversity decreased in ISDD model but increased in DSR model. In contrast to ISDD model, the overall abundance of dsr genes was lower in DSR model, while some functional genes targeting from nitrate-reducing sulfide-oxidizing bacteria (NR-SOB), such as Thiobacillus denitrificans, Sulfurimonas denitrificans, and Paracoccus pantotrophus were more abundant in DSR model which were highly associated with the change of S(0) conversion rate obtained in two models. The results obtained in this study provide additional insights into the microbial metabolic mechanisms involved in ISDD and DSR models, which in turn will improve the overall performance of SDD process. Copyright © 2014. Published by Elsevier B.V.

Purifying Nucleic Acids from Samples of Extremely Low Biomass

NASA Technical Reports Server (NTRS)

La Duc, Myron; Osman, Shariff; Venkateswaran, Kasthuri

2008-01-01

A new method is able to circumvent the bias to which one commercial DNA extraction method falls prey with regard to the lysing of certain types of microbial cells, resulting in a truncated spectrum of microbial diversity. By prefacing the protocol with glass-bead-beating agitation (mechanically lysing a much more encompassing array of cell types and spores), the resulting microbial diversity detection is greatly enhanced. In preliminary studies, a commercially available automated DNA extraction method is effective at delivering total DNA yield, but only the non-hardy members of the bacterial bisque were represented in clone libraries, suggesting that this method was ineffective at lysing the hardier cell types. To circumvent such a bias in cells, yet another extraction method was devised. In this technique, samples are first subjected to a stringent bead-beating step, and then are processed via standard protocols. Prior to being loaded into extraction vials, samples are placed in micro-centrifuge bead tubes containing 50 micro-L of commercially produced lysis solution. After inverting several times, tubes are agitated at maximum speed for two minutes. Following agitation, tubes are centrifuged at 10,000 x g for one minute. At this time, the aqueous volumes are removed from the bead tubes and are loaded into extraction vials to be further processed via extraction regime. The new method couples two independent methodologies in such as way as to yield the highest concentration of PCR-amplifiable DNA with consistent and reproducible results and with the most accurate and encompassing report of species richness.

Rapid and quantitative detection of the microbial spoilage of meat by fourier transform infrared spectroscopy and machine learning.

PubMed

Ellis, David I; Broadhurst, David; Kell, Douglas B; Rowland, Jem J; Goodacre, Royston

2002-06-01

Fourier transform infrared (FT-IR) spectroscopy is a rapid, noninvasive technique with considerable potential for application in the food and related industries. We show here that this technique can be used directly on the surface of food to produce biochemically interpretable "fingerprints." Spoilage in meat is the result of decomposition and the formation of metabolites caused by the growth and enzymatic activity of microorganisms. FT-IR was exploited to measure biochemical changes within the meat substrate, enhancing and accelerating the detection of microbial spoilage. Chicken breasts were purchased from a national retailer, comminuted for 10 s, and left to spoil at room temperature for 24 h. Every hour, FT-IR measurements were taken directly from the meat surface using attenuated total reflectance, and the total viable counts were obtained by classical plating methods. Quantitative interpretation of FT-IR spectra was possible using partial least-squares regression and allowed accurate estimates of bacterial loads to be calculated directly from the meat surface in 60 s. Genetic programming was used to derive rules showing that at levels of 10(7) bacteria.g(-1) the main biochemical indicator of spoilage was the onset of proteolysis. Thus, using FT-IR we were able to acquire a metabolic snapshot and quantify, noninvasively, the microbial loads of food samples accurately and rapidly in 60 s, directly from the sample surface. We believe this approach will aid in the Hazard Analysis Critical Control Point process for the assessment of the microbiological safety of food at the production, processing, manufacturing, packaging, and storage levels.

Co-metabolic enhancement of organic removal from waste water in the presence of high levels of alkyl paraben constituents of cosmetic and personal care products.

PubMed

Fan, Chihhao; Wang, Shin-Chih

2017-07-01

The enhanced removal of organic material from municipal waste water containing 50 mg/L of chemical oxygen demand and a given amount of alkyl paraben using a biofilm system was investigated. The parabens used were methyl, ethyl, and propyl paraben. The experiments were conducted at influent paraben concentrations of 10 and 50 mg/L. The influent pH was measured around 4.6 because of paraben hydrolysis. The effluent pH increased due to hydrogen consumption and small molecular acid generation. The higher removal rates were observed for the paraben with longer alkyl chains, which were more hydrophobic and capable of penetrating into microbial cells. The co-existing organic constituents in municipal waste water were found to be competitive with paraben molecules for microbial degradation at low paraben loading (i.e., 10 mg/L). Instead, the co-metabolic effect was observed at a higher paraben loading (i.e., 50 mg/L) due to more active enzymatic catalysis, implying the possible enhancement or organic removal in the presence of high levels of parabens. The difference in BOD and TOC removing ratios for parabens decreased with increasing HRT, implying their better mineralization than that of municipal organic constituents. This was because the microbial organism became more adapted to the reacting system with longer HRT, and more oxygenase was produced to facilitate the catechol formation and ring-opening reactions, causing apparent enhancement in mineralization. Copyright © 2017 Elsevier Ltd. All rights reserved.

[Bile-resistant Gram-negative bacteria effect of different kinds of root decoction pieces].

PubMed

Deng, Yan; Wang, Ya-Ke; Han, Xiao-Yu; Wang, Ya-Qi; Jiang, Zhen-Yu; Yu, Zhi-Jun; Deng, Hai-Ying

2017-11-01

To investigate the microbial contamination in Chinese herbal decoction pieces with different functional types by studying the total aerobic microbial count (TAMC), and total yeast and mould count (TYMC) in 40 samples of 8 types of root decoction pieces; further evaluate the contamination load of bile-resistant Gram-negative bacteria, and identify the Gram-negative bacteria by using biochemical identification system for Gram-negative bacteria. Our results showed that the TAMC value was more than 1 000 CFU•g⁻¹ in 85% (34/40) samples, and was more than 100 CFU•g⁻¹ in 30% (12/40) samples; the contamination of bile-resistant Gram-negative bacteria was detected in 45% (18/40) of the samples. The bile-resistant Gram-negative bacteria load of seven batches of samples was N>1 000 MPN•g⁻¹. Sixteen bacterium strains including Serratia plymouthensis, Cedecea neteri, Escherichia vulneris, Klebsiella oxytoca, Enterobacter amnigenus, E. cloacae, E. sakazakii, Proteus penneri and E. gergoviae were obtained and identified. E. cloacae was the predominant bacterium that was isolated from Salviae Miltiorrhizae Radix et Rhizoma, while E. amnigenus, Yersinia pseudotuberculosis was the typical bacterium of Ophiopogonis Radix and Codonopsis Radix, respectively. All these suggested that the contamination of bile-resistant Gram-negative bacteria was severe for the root decoction pieces in Wuhan city. Microbial species have certain selection specificity for medicinal ingredients, so the type and limit of control bacteria for detection should be formulated according to the pollution type and quantity of bile-resistant Gram-negative bacteria. Copyright© by the Chinese Pharmaceutical Association.

Soil nitrogen mineralization and enzymatic activities in fire and fire surrogate treatments in California

Treesearch

J. R. Miesel; R. E. J. Boerner; C. N. Skinner

2011-01-01

Forest thinning and prescribed fire are management strategies used to reduce hazardous fuel loads and catastrophic wildfires in western mixed-conifer forests. We evaluated effects of thinning (Thin) and prescribed fire (Burn), alone and in combination (Thin+Burn), on N transformations and microbial enzyme activities relative to an untreated control (Control) at 1 and 3...

Chemometrical assessment of the electrical parameters obtained by long-term operating freshwater sediment microbial fuel cells.

PubMed

Mitov, Mario; Bardarov, Ivo; Mandjukov, Petko; Hubenova, Yolina

2015-12-01

The electrical parameters of nine freshwater sediment microbial fuel cells (SMFCs) were monitored for a period of over 20 months. The developed SMFCs, divided into three groups, were started up and continuously operated under different constant loads (100, 510 and 1100 Ω) for 2.5 months. At this stage of the experiment, the highest power density values, reaching 1.2 ± 0.2 mW/m(2), were achieved by the SMFCs loaded with 510 Ω. The maximum power obtained at periodical polarization during the rest period, however, ranged between 26.2 ± 2.8 and 35.3 ± 2.8 mW/m(2), strongly depending on the internal cell resistance. The statistical evaluation of data derived from the polarization curves shows that after 300 days of operation all examined SMFCs reached a steady-state and the system might be assumed as homoscedastic. The estimated values of standard and expanded uncertainties of the electric parameters indicate a high repeatability and reproducibility of the SMFCs' performance. Results obtained in subsequent discharge-recovery cycles reveal the opportunity for practical application of studied SMFCs as autonomous power sources.

Growth of Salmonella on sprouting alfalfa seeds as affected by the inoculum size, native microbial load and Pseudomonas fluorescens 2-79.

PubMed

Liao, C-H

2008-02-01

To investigate the growth of salmonellae on sprouting alfalfa seeds as affected by the inoculum size, microbial load and Pseudomonas fluorescens 2-79. Alfalfa seeds pre-inoculated with < or =10(1)-10(3) CFU g(-1) of salmonellae and with or without Ps. fluorescens 2-79 were sprouted in glass jars and the population of salmonellae were determined daily for up to 6 days. The population of salmonellae on germinating seeds reached the maximum 2-3 days after sprouting when total bacterial count reached the maximum (10(9) CFU g(-1)). The population of salmonellae on sprouting seeds not treated with Ps. fluorescens 2-79 showed a net increase of 3-4 log units. However, the population of salmonellae on alfalfa seeds treated with Ps. fluorescens 2-79 showed a net increase of only 1-2 log units. Disinfection of seeds with calcium hypochlorite enhanced the growth of salmonellae. Treatment of seeds with Ps. fluorescens 2-79 reduced the growth of salmonellae by 2-3 log units. The potential of Ps. fluorescens 2-79 as a biological agent for use in control of salmonellae on sprouting seeds was demonstrated and warrants further investigation.

A new apparatus to induce lysis of planktonic microbial cells by shock compression, cavitation and spray

PubMed Central

Schiffer, A.; Gardner, M. N.; Lynn, R. H.

2017-01-01

Experiments were conducted on an aqueous growth medium containing cultures of Escherichia coli (E. coli) XL1-Blue, to investigate, in a single experiment, the effect of two types of dynamic mechanical loading on cellular integrity. A bespoke shock tube was used to subject separate portions of a planktonic bacterial culture to two different loading sequences: (i) shock compression followed by cavitation, and (ii) shock compression followed by spray. The apparatus allows the generation of an adjustable loading shock wave of magnitude up to 300 MPa in a sterile laboratory environment. Cultures of E. coli were tested with this apparatus and the spread-plate technique was used to measure the survivability after mechanical loading. The loading sequence (ii) gave higher mortality than (i), suggesting that the bacteria are more vulnerable to shear deformation and cavitation than to hydrostatic compression. We present the results of preliminary experiments and suggestions for further experimental work; we discuss the potential applications of this technique to sterilize large volumes of fluid samples. PMID:28405383

A new apparatus to induce lysis of planktonic microbial cells by shock compression, cavitation and spray.

PubMed

Schiffer, A; Gardner, M N; Lynn, R H; Tagarielli, V L

2017-03-01

Experiments were conducted on an aqueous growth medium containing cultures of Escherichia coli ( E. coli ) XL1-Blue, to investigate, in a single experiment, the effect of two types of dynamic mechanical loading on cellular integrity. A bespoke shock tube was used to subject separate portions of a planktonic bacterial culture to two different loading sequences: (i) shock compression followed by cavitation, and (ii) shock compression followed by spray. The apparatus allows the generation of an adjustable loading shock wave of magnitude up to 300 MPa in a sterile laboratory environment. Cultures of E. coli were tested with this apparatus and the spread-plate technique was used to measure the survivability after mechanical loading. The loading sequence (ii) gave higher mortality than (i), suggesting that the bacteria are more vulnerable to shear deformation and cavitation than to hydrostatic compression. We present the results of preliminary experiments and suggestions for further experimental work; we discuss the potential applications of this technique to sterilize large volumes of fluid samples.

Spoilage microbiota associated to the storage of raw meat in different conditions.

PubMed

Doulgeraki, Agapi I; Ercolini, Danilo; Villani, Francesco; Nychas, George-John E

2012-07-02

The spoilage of raw meat is mainly due to undesired microbial development in meat during storage. The type of bacteria and their loads depend on the initial meat contamination and on the specific storage conditions that can influence the development of different spoilage-related microbial populations thus affecting the type and rate of the spoilage process. This review focuses on the composition of raw meat spoilage microbiota and the influence of storage conditions such as temperature, packaging atmosphere and use of different preservatives on the bacterial diversity developing in raw meat. In addition, the most recent tools used for the detection and identification of meat microbiota are also reviewed. Copyright © 2012 Elsevier B.V. All rights reserved.

High power density microbial fuel cell with flexible 3D graphene-nickel foam as anode

NASA Astrophysics Data System (ADS)

Wang, Hanyu; Wang, Gongming; Ling, Yichuan; Qian, Fang; Song, Yang; Lu, Xihong; Chen, Shaowei; Tong, Yexiang; Li, Yat

2013-10-01

The structure and electrical conductivity of anode play a significant role in the power generation of microbial fuel cells (MFCs). In this study, we developed a three-dimensional (3D) reduced graphene oxide-nickel (denoted as rGO-Ni) foam as an anode for MFC through controlled deposition of rGO sheets onto the nickel foam substrate. The loading amount of rGO sheets and electrode surface area can be controlled by the number of rGO loading cycles. 3D rGO-Ni foam anode provides not only a large accessible surface area for microbial colonization and electron mediators, but also a uniform macro-porous scaffold for effective mass diffusion of the culture medium. Significantly, at a steady state of the power generation, the MFC device with flexible rGO-Ni electrodes produced an optimal volumetric power density of 661 W m-3 calculated based on the volume of anode material, or 27 W m-3 based on the volume of the anode chamber. These values are substantially higher than that of plain nickel foam, and other conventional carbon based electrodes (e.g., carbon cloth, carbon felt, and carbon paper) measured in the same conditions. To our knowledge, this is the highest volumetric power density reported for mL-scale MFC device with a pure strain of Shewanella oneidensis MR-1. We also demonstrated that the MFC device can be operated effectively in a batch-mode at least for a week. These new 3D rGO-Ni electrodes show great promise for improving the power generation of MFC devices.The structure and electrical conductivity of anode play a significant role in the power generation of microbial fuel cells (MFCs). In this study, we developed a three-dimensional (3D) reduced graphene oxide-nickel (denoted as rGO-Ni) foam as an anode for MFC through controlled deposition of rGO sheets onto the nickel foam substrate. The loading amount of rGO sheets and electrode surface area can be controlled by the number of rGO loading cycles. 3D rGO-Ni foam anode provides not only a large accessible surface area for microbial colonization and electron mediators, but also a uniform macro-porous scaffold for effective mass diffusion of the culture medium. Significantly, at a steady state of the power generation, the MFC device with flexible rGO-Ni electrodes produced an optimal volumetric power density of 661 W m-3 calculated based on the volume of anode material, or 27 W m-3 based on the volume of the anode chamber. These values are substantially higher than that of plain nickel foam, and other conventional carbon based electrodes (e.g., carbon cloth, carbon felt, and carbon paper) measured in the same conditions. To our knowledge, this is the highest volumetric power density reported for mL-scale MFC device with a pure strain of Shewanella oneidensis MR-1. We also demonstrated that the MFC device can be operated effectively in a batch-mode at least for a week. These new 3D rGO-Ni electrodes show great promise for improving the power generation of MFC devices. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr03487a

Hard surface biocontrol in hospitals using microbial-based cleaning products.

PubMed

Vandini, Alberta; Temmerman, Robin; Frabetti, Alessia; Caselli, Elisabetta; Antonioli, Paola; Balboni, Pier Giorgio; Platano, Daniela; Branchini, Alessio; Mazzacane, Sante

2014-01-01

Healthcare-Associated Infections (HAIs) are one of the most frequent complications occurring in healthcare facilities. Contaminated environmental surfaces provide an important potential source for transmission of many healthcare-associated pathogens, thus indicating the need for new and sustainable strategies. This study aims to evaluate the effect of a novel cleaning procedure based on the mechanism of biocontrol, on the presence and survival of several microorganisms responsible for HAIs (i.e. coliforms, Staphyloccus aureus, Clostridium difficile, and Candida albicans) on hard surfaces in a hospital setting. The effect of microbial cleaning, containing spores of food grade Bacillus subtilis, Bacillus pumilus and Bacillus megaterium, in comparison with conventional cleaning protocols, was evaluated for 24 weeks in three independent hospitals (one in Belgium and two in Italy) and approximately 20000 microbial surface samples were collected. Microbial cleaning, as part of the daily cleaning protocol, resulted in a reduction of HAI-related pathogens by 50 to 89%. This effect was achieved after 3-4 weeks and the reduction in the pathogen load was stable over time. Moreover, by using microbial or conventional cleaning alternatively, we found that this effect was directly related to the new procedure, as indicated by the raise in CFU/m2 when microbial cleaning was replaced by the conventional procedure. Although many questions remain regarding the actual mechanisms involved, this study demonstrates that microbial cleaning is a more effective and sustainable alternative to chemical cleaning and non-specific disinfection in healthcare facilities. This study indicates microbial cleaning as an effective strategy in continuously lowering the number of HAI-related microorganisms on surfaces. The first indications on the actual level of HAIs in the trial hospitals monitored on a continuous basis are very promising, and may pave the way for a novel and cost-effective strategy to counteract or (bio)control healthcare-associated pathogens.

Hard Surface Biocontrol in Hospitals Using Microbial-Based Cleaning Products

PubMed Central

Vandini, Alberta; Temmerman, Robin; Frabetti, Alessia; Caselli, Elisabetta; Antonioli, Paola; Balboni, Pier Giorgio; Platano, Daniela; Branchini, Alessio; Mazzacane, Sante

2014-01-01

Background Healthcare-Associated Infections (HAIs) are one of the most frequent complications occurring in healthcare facilities. Contaminated environmental surfaces provide an important potential source for transmission of many healthcare-associated pathogens, thus indicating the need for new and sustainable strategies. Aim This study aims to evaluate the effect of a novel cleaning procedure based on the mechanism of biocontrol, on the presence and survival of several microorganisms responsible for HAIs (i.e. coliforms, Staphyloccus aureus, Clostridium difficile, and Candida albicans) on hard surfaces in a hospital setting. Methods The effect of microbial cleaning, containing spores of food grade Bacillus subtilis, Bacillus pumilus and Bacillus megaterium, in comparison with conventional cleaning protocols, was evaluated for 24 weeks in three independent hospitals (one in Belgium and two in Italy) and approximately 20000 microbial surface samples were collected. Results Microbial cleaning, as part of the daily cleaning protocol, resulted in a reduction of HAI-related pathogens by 50 to 89%. This effect was achieved after 3–4 weeks and the reduction in the pathogen load was stable over time. Moreover, by using microbial or conventional cleaning alternatively, we found that this effect was directly related to the new procedure, as indicated by the raise in CFU/m2 when microbial cleaning was replaced by the conventional procedure. Although many questions remain regarding the actual mechanisms involved, this study demonstrates that microbial cleaning is a more effective and sustainable alternative to chemical cleaning and non-specific disinfection in healthcare facilities. Conclusions This study indicates microbial cleaning as an effective strategy in continuously lowering the number of HAI-related microorganisms on surfaces. The first indications on the actual level of HAIs in the trial hospitals monitored on a continuous basis are very promising, and may pave the way for a novel and cost-effective strategy to counteract or (bio)control healthcare-associated pathogens. PMID:25259528

Sulfide and ammonium oxidation, acetate mineralization by denitrification in a multipurpose UASB reactor.

PubMed

Beristain-Cardoso, Ricardo; Gómez, Jorge; Méndez-Pampín, Ramón

2011-02-01

The physiological and kinetic behavior of a denitrifying granular sludge exposed to different sulfide loading rates (55-295 mg/L d) were evaluated in a UASB reactor fed with acetate, ammonium and nitrate. At any sulfide loading rates, the consumption efficiencies of sulfide, acetate and ammonium were above 95%, while nitrate consumption efficiencies were around 62-72%. At the highest sulfide loading rate the ammonium was used as electron donor for N(2) production. The increase of sulfide loading rate also affected the fate of sulfide oxidation, since elemental sulfur was the main end product instead of sulfate. However, the lithotrophic denitrifying kinetic was not affected. FISH oligonucleotide probes for Thiobacillus denitrificans, Thiomiscropira denitrificans, genus Paracoccus and Pseudomonas spp. were used to follow the microbial ecology. The results of this work have shown that four pollutants could simultaneously be removed, namely, sulfide, ammonium, acetate and nitrate under well defined denitrifying conditions. Copyright © 2010 Elsevier Ltd. All rights reserved.

Post carbon removal nitrifying MBBR operation at high loading and exposure to starvation conditions.

PubMed

Young, Bradley; Delatolla, Robert; Kennedy, Kevin; LaFlamme, Edith; Stintzi, Alain

2017-09-01

This study investigates the performance of MBBR nitrifying biofilm post carbon removal at high loading and starvation conditions. The nitrifying MBBR, treating carbon removal lagoon effluent, achieved a maximum SARR of 2.13gN/m 2 d with complete conversion of ammonia to nitrate. The results also show the MBBR technology is capable of maintaining a stable biofilm under starvation conditions in systems that nitrify intermittently. The biomass exhibited a higher live fraction of total cells in the high loaded reactors (73-100%) as compared to the reactors operated in starvation condition (26-82%). For both the high loaded and starvation condition, the microbial communities significantly changed with time of operation. The nitrifying community, however, remained steady with the family Nitrosomonadacea as the primary AOBs and Nitrospira as the primary NOB. During starvation conditions, the relative abundance of AOBs decreased and Nitrospira increased corresponding to an NOB/AOB ratio of 5.2-12.1. Copyright © 2017 Elsevier Ltd. All rights reserved.

Climate variability and extremes, interacting with nitrogen storage, amplify eutrophication risk

USGS Publications Warehouse

Lee, Minjin; Shevliakova, Elena; Malyshev, Sergey; Milly, P.C.D.; Jaffe, Peter R.

2016-01-01

Despite 30 years of basin-wide nutrient-reduction efforts, severe hypoxia continues to be observed in the Chesapeake Bay. Here we demonstrate the critical influence of climate variability, interacting with accumulated nitrogen (N) over multidecades, on Susquehanna River dissolved nitrogen (DN) loads, known precursors of the hypoxia in the Bay. We used the process model LM3-TAN (Terrestrial and Aquatic Nitrogen), which is capable of capturing both seasonal and decadal-to-century changes in vegetation-soil-river N storage, and produced nine scenarios of DN-load distributions under different short-term scenarios of climate variability and extremes. We illustrate that after 1 to 3 yearlong dry spells, the likelihood of exceeding a threshold DN load (56 kt yr−1) increases by 40 to 65% due to flushing of N accumulated throughout the dry spells and altered microbial processes. Our analyses suggest that possible future increases in climate variability/extremes—specifically, high precipitation occurring after multiyear dry spells—could likely lead to high DN-load anomalies and hypoxia.

Comparative analysis of ampoules and vials in sterile and conventional packaging as to microbial load and sterility test.

PubMed

Freitas, Raphael Ribeiro de Aquino; Tardelli, Maria Angela

2016-05-24

To compare sterility and microbial (bacteria and fungi) load in the outer part of hyperbaric bupivacaine (Neocaína®) in ampoule and bupivacaine in vial, in conventional and sterile pack formulations. The sterile packs were divided into two groups: G1 (n=16) with ampoules and G2 (n=16) with vials. Conventional formulations were divided into two groups, being G3 (n=16) with ampoules and G4 (n=16) with vials. The ampoules and vials were opened and had their content drawn. The empty bottles were then placed in sterile plastic bags and sent for analysis of microbial load (bacteria and fungi) and sterility testing. Data were analyzed using the χ2 test with Yates correction, and 95% confidence interval. G1 and G2 showed no bacterial growth when compared to conventional groups (p<0.001). The most common agent in conventional microbiological samples was Staphylococcus aureus. There was no fungal growth in both groups. The use of (sterile pack) reduces the microbial load of bottles, and would decrease the chance of exposure to potential contamination of the anesthetic solution. Comparar a esterilidade e a carga microbiana (bactérias e fungos) da parte externa dos frascos de envasamento de bupivacaína hiperbárica (Neocaína®) em ampola e bupivacaína em frasco-ampola das apresentações convencional e estéril (sterile pack). As apresentações estéreis (sterile pack) foram distribuídas em dois grupos, sendo que o G1 (n=16) continha as ampolas e o G2 (n=16), os frascos-ampola. As apresentações convencionais foram distribuídas em dois grupos, a saber G3 (n=16) com as ampolas e G4 (n=16) com os frascos-ampola. As ampolas e os frascos-ampolas eram abertos e tinham seu conteúdo aspirado. Os frascos vazios eram, então, acondicionados em sacos plásticos estéreis e enviados para análise quanto à carga microbiana (bactérias e fungos), bem como para o teste de esterilidade. Os dados foram analisados por meio do teste χ2 com correção Yates com intervalo de confiança de 95%. Os grupos G1 e G2 não apresentaram crescimento bacteriano quando comparado aos grupos convencionais (p<0,001). O microbiano mais comum nas amostras convencionais foi o Staphylococcus aureus. Não houve crescimento de fungos em nenhum dos grupos. O uso de embalagens estéreis (sterile pack) diminui a carga microbiana dos frascos de envasamentos, o que diminuiria a chance de exposição a uma potencial contaminação da solução anestésica.

The impact of dairy cows' bedding material and its microbial content on the quality and safety of milk - A cross sectional study of UK farms.

PubMed

Bradley, Andrew J; Leach, Katharine A; Green, Martin J; Gibbons, Jenny; Ohnstad, Ian C; Black, David H; Payne, Barbara; Prout, Victoria E; Breen, James E

2018-03-23

The introduction of bedding dairy cows on recycled manure solids (RMS) in the UK led to concern by competent authorities that there could be an increased, unacceptable risk to animal and human health. A cross-sectional study was designed to evaluate the microbial content of different bedding materials, when used by dairy cows, and its impact on the microbial content of milk. Data were collected from farms bedding lactating cows on sand (n=41), sawdust (n=44) and RMS (n=40). The mean duration of RMS use prior to sampling was 13months. Total bacterial count, and counts of Streptococcus/Enterococcus spp., Staphylococcus spp., Bacillus cereus, thermophilic, thermoduric and psychrotrophic bacteria were determined in used bedding and milk. Samples were evaluated for the presence/absence of Listeria monocytogenes, Salmonella spp. and Yersinia enterocolitica. Data on milking practices were collected to investigate their potential to reduce microbial transfer from bedding to milk. There were substantial differences in bacterial counts both within and between bedding materials. However, there were no significant differences between bedding groups in counts in milk for any of the organisms studied, and no significant correlations between bacterial load in used bedding and milk. Fore-milking was associated with a reduced total bacterial count in milk. Dipping teats with disinfectant and drying, prior to milking, was associated with lower numbers of Streptococcus/Enterococcus spp. in milk. Disinfecting clusters between milking different cows was associated with a reduction in thermophilic and psychrotrophic counts in milk. This study did not provide evidence that use of RMS bedding increased the risk of presence of Y. enterocolitica, Salmonella spp. or L. monocytogenes in milk. However, the strength of this conclusion should be tempered by the relatively small number of farms on which Y. enterocolitica and Salmonella spp. were isolated. It is concluded that, despite the higher bacterial load of RMS, its use as bedding for lactating dairy cows need not be associated with a higher bacterial load in milk than the use of sand or sawdust. However, this finding must be interpreted in the light of the relatively recent introduction of RMS as a bedding material on the farms studied. Teat preparation provides a control point for the potential transfer of microorganisms from bedding to milk. The detection of zoonotic pathogens in a small proportion of milk samples, independent of bedding type, indicates that pasteurisation of milk prior to human consumption remains an important control measure. Copyright © 2017 Elsevier B.V. All rights reserved.

Preslaughter diet management in sheep and goats: effects on physiological responses and microbial loads on skin and carcass

PubMed Central

2014-01-01

Sixteen crossbred buck goats (Kiko x Spanish; BW = 32.8 kg) and wether sheep (Dorset x Suffolk; BW = 39.9 kg) were used to determine the effect of preslaughter diet and feed deprivation time (FDT) on physiological responses and microbial loads on skin and carcasses. Experimental animals were fed either a concentrate (CD) or a hay diet (HD) for 4 d and then deprived of feed for either 12-h or 24-h before slaughter. Blood samples were collected for plasma cortisol and blood metabolite analyses. Longisimus muscle (LM) pH was measured. Skin and carcass swabs were obtained to assess microbial loads. Plasma creatine kinase activity (863.9 and 571.7 ± 95.21 IU) and non-esterified fatty acid concentrations (1,056.1 and 589.8 ± 105.01 mEq/L) were different (P < 0.05) between sheep and goats. Species and diet treatments had significant effects on the ultimate pH of LM. Pre-holding total coliform (TCC) and aerobic plate counts (APC) of skin were significantly different between species. Goats had lower (P < 0.05) TCC (2.1 vs. 3.0 log10 CFU/cm2) and APC (8.2 vs. 8.5 log10 CFU/cm2) counts in the skin compared to sheep. Preslaughter skin E. coli counts and TCC were different (P < 0.05) between species. Goats had lower (P < 0.05) counts of E. coli (2.2 vs. 2.9 log10 CFU/cm2) and TCC (2.3 vs. 3.0 log10 CFU/cm2) in the skin compared with those in sheep. Diet, species, and FDT had no effect (P > 0.05) on E. coli and TCC in carcass swab samples. The APC of carcass swab samples were only affected (P < 0.05) by the FDT. The results indicated that preslaughter dietary management had no significant changes on hormone and blood metabolite concentrations and sheep might be more prone for fecal contamination than goats in the holding pens at abattoir. PMID:25343027

Bacteria that Travel: The Quality of Aircraft Water

PubMed Central

Handschuh, Harald; Dwyer, Jean O’; Adley, Catherine C.

2015-01-01

The travelling population is increasing globally year on year. International tourist arrival figures reached 1087 million in 2013 and 1133 million in 2014; of which 53% and 54% respectively accounted for air transport. The water on board aircraft is sourced from surface or ground water; piped to a central filling point and distributed to each aircraft by water service vehicles at the home base or at the destination airport. The purpose of this study was to ascertain the microbial, chemical (pH; Total and Free chlorine) and physical (temperature) quality of water from two aircraft, long- and short-haul, as well as from the original water source and the water service vehicle. A total of 154 water samples were collected and analysed. Long-haul flights were found to be significantly poorer in terms of microbial quality than short haul flights (p = 0.015). Furthermore, correlation and regression analysis showed that the water service vehicle was a significant source of increased microbial load in aircraft. Microbial diversity was also demonstrated, with 37 bacterial species identified belonging to eight classes: γ-Proteobacteria; β-Proteobacteria; α-Proteobacteria; Bacilli; Actinobacteria; Flavobacteria; Sphingobacteria and Cytophaga; using phenotypic and 16S rDNA sequence-based analysis. We present a novel quantified study of aircraft-related potable water supplies. PMID:26529000

A paper-based microbial fuel cell array for rapid and high-throughput screening of electricity-producing bacteria.

PubMed

Choi, Gihoon; Hassett, Daniel J; Choi, Seokheun

2015-06-21

There is a large global effort to improve microbial fuel cell (MFC) techniques and advance their translational potential toward practical, real-world applications. Significant boosts in MFC performance can be achieved with the development of new techniques in synthetic biology that can regulate microbial metabolic pathways or control their gene expression. For these new directions, a high-throughput and rapid screening tool for microbial biopower production is needed. In this work, a 48-well, paper-based sensing platform was developed for the high-throughput and rapid characterization of the electricity-producing capability of microbes. 48 spatially distinct wells of a sensor array were prepared by patterning 48 hydrophilic reservoirs on paper with hydrophobic wax boundaries. This paper-based platform exploited the ability of paper to quickly wick fluid and promoted bacterial attachment to the anode pads, resulting in instant current generation upon loading of the bacterial inoculum. We validated the utility of our MFC array by studying how strategic genetic modifications impacted the electrochemical activity of various Pseudomonas aeruginosa mutant strains. Within just 20 minutes, we successfully determined the electricity generation capacity of eight isogenic mutants of P. aeruginosa. These efforts demonstrate that our MFC array displays highly comparable performance characteristics and identifies genes in P. aeruginosa that can trigger a higher power density.

Development of dielectric barrier discharge for reducing microbial contamination in pepper (Piper nigrum) and sesame (Sesamum indicum Linn.) powder

NASA Astrophysics Data System (ADS)

Promping, J.; Prakongsil, P.; Picha, R.; Traikool, T.

2017-09-01

This research is designed to determine the efficacy of DBD plasma to reduce the microbial contamination of pepper and sesame powder. The AC high voltage power supply was used with voltages of up to 20 kV and the frequency of 5.5 kHz was applied to the DBD. The gap of DBD electrodes was set at 5 mm. In raw initial samples, the total aerobic count of pepper (Piper nigrum) was found at quite a high level at 5.40 × 105 CFU/g. Coliform bacteria was also found in both the sesame (Sesamum indicum Linn.) powder and pepper (Piper nigrum) powder. Both kinds of samples were treated with plasma for 2, 4, 6 and 10 minutes. Results indicated that plasma treatment at 2-10 minutes reduced the total aerobic count of pepper allowed to achieve the acceptable microbial level for spices. The plasma treatment times in this experiment were also effective in reducing faecal coliform bacteria in both pepper and sesame powders (MPN/g <3) as indicated in the standard. Plasma from dielectric barrier charge can reduce Staphylococcus epidermidis in sesame powder which was artificially contaminated with 3.50 × 102 CFU/g resulting in 0.15-0.5 log cycle reductions of microbial load.

Bacteria that Travel: The Quality of Aircraft Water.

PubMed

Handschuh, Harald; O'Dwyer, Jean; Adley, Catherine C

2015-10-30

The travelling population is increasing globally year on year. International tourist arrival figures reached 1087 million in 2013 and 1133 million in 2014; of which 53% and 54% respectively accounted for air transport. The water on board aircraft is sourced from surface or ground water; piped to a central filling point and distributed to each aircraft by water service vehicles at the home base or at the destination airport. The purpose of this study was to ascertain the microbial, chemical (pH; Total and Free chlorine) and physical (temperature) quality of water from two aircraft, long- and short-haul, as well as from the original water source and the water service vehicle. A total of 154 water samples were collected and analysed. Long-haul flights were found to be significantly poorer in terms of microbial quality than short haul flights (p = 0.015). Furthermore, correlation and regression analysis showed that the water service vehicle was a significant source of increased microbial load in aircraft. Microbial diversity was also demonstrated, with 37 bacterial species identified belonging to eight classes: γ-Proteobacteria; β-Proteobacteria; α-Proteobacteria; Bacilli; Actinobacteria; Flavobacteria; Sphingobacteria and Cytophaga; using phenotypic and 16S rDNA sequence-based analysis. We present a novel quantified study of aircraft-related potable water supplies.

Air sampling methods to evaluate microbial contamination in operating theatres: results of a comparative study in an orthopaedics department.

PubMed

Napoli, C; Tafuri, S; Montenegro, L; Cassano, M; Notarnicola, A; Lattarulo, S; Montagna, M T; Moretti, B

2012-02-01

To evaluate the level of microbial contamination of air in operating theatres using active [i.e. surface air system (SAS)] and passive [i.e. index of microbial air contamination (IMA) and nitrocellulose membranes positioned near the wound] sampling systems. Sampling was performed between January 2010 and January 2011 in the operating theatre of the orthopaedics department in a university hospital in Southern Italy. During surgery, the mean bacterial loads recorded were 2232.9 colony-forming units (cfu)/m(2)/h with the IMA method, 123.2 cfu/m(3) with the SAS method and 2768.2 cfu/m(2)/h with the nitrocellulose membranes. Correlation was found between the results of the three methods. Staphylococcus aureus was detected in 12 of 60 operations (20%) with the membranes, five (8.3%) operations with the SAS method, and three operations (5%) with the IMA method. Use of nitrocellulose membranes placed near a wound is a valid method for measuring the microbial contamination of air. This method was more sensitive than the IMA method and was not subject to any calibration bias, unlike active air monitoring systems. Copyright © 2011 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Nitrogen removal characteristics analyzed with gas and microbial community in thermophilic aerobic digestion for piggery waste treatment.

PubMed

Lee, J W; Lee, H W; Kim, S W; Lee, S Y; Park, Y K; Han, J H; Choi, S I; Yi, Y S; Yun, Z

2004-01-01

In order to characterize the nitrogen conversion characteristics in a thermophilic aerobic digestion (TAD) system, a laboratory study has been conducted with the analysis of effluent gas and microbial community in the sludge samples. The lab TAD system was operated with HRT of 3 days and 60 degrees C. Based on the nitrogen mass balance, it has been found that about 2/3 of the daily load of nitrogen was converted to the gaseous form of nitrogen whereas cellular transformation and unmetabolized nitrogen accounted for about 1/3. Among the gaseous nitrogen transformation, significant amount of influent nitrogen had been converted to N2 gas (29% of influent N) and N2O (9% of influent N). Ammonia conversion was only 28% of influent N. The detection of N2O gas is a clear indication of the biological nitrogen reduction process in the thermophilic aerobic digester. No conclusive evidence for the existence of aerobic deammonification has been found. The microbial community analysis showed that thermophilic bacteria such as Bacillus thermocloacae, Bacillus sp. and Clostridial groups dominated in this TAD reactor. The diverse microbial community in TAD sludge may play an important role in removing both strong organics and nitrogen from piggery waste.

Microbiological profile and potential hazards associated with imported and local brands of tomato paste in Nigeria.

PubMed

Efiuvwevwere, B J; Atirike, O I

1998-03-01

Cans of three tomato paste brands (two of which are imported and one produced locally) showing defective or normal appearance were purchased from various retail outlets and analysed for microbial composition and pH values. Substantially higher total viable counts were observed in samples from defective cans but the lowest population was found in the local brand. Ratio of mesophilic to thermophilic micro-organisms increased in samples obtained from cans showing visible defects. Anaerobic spore counts were higher than the aerobic population in both normal and defective cans, but the counts varied with the brands. Four dominant bacterial genera (Bacillus, Clostridium, Lactobacillus and Leuconostoc) were isolated from the samples with the greater proportion being spore-formers. Percentage occurrence of Clostridium thermosaccharolyticum was appreciably higher in samples from defective cans while a preponderance of Lactobacillus occurred in samples from normal cans. Of the moulds isolated, Absidia and Aspergillus fumigatus showed a higher percentage in defective cans. pH values higher than the critical safe level of 4.6 were found in cans with visible defects and greater microbial diversity with higher microbial load was more often associated with these samples. Imported brands showed more undesirable microbial quality and pH values, making them potentially hazardous.

Microbiota in experimental periodontitis and peri-implantitis in dogs.

PubMed

Charalampakis, Georgios; Abrahamsson, Ingemar; Carcuac, Olivier; Dahlén, Gunnar; Berglundh, Tord

2014-09-01

To analyze the microbial profile around teeth and implants following ligature removal in experimental periodontitis and peri-implantitis in dogs. Four implants with similar geometry and with two different surface characteristics (implant A: turned/implant B: TiUnite; NobelBiocare AB) were placed pairwise in the right side of the mandible 3 months after tooth extraction in five dogs. Experimental periodontitis and peri-implantitis were initiated 3 months later by ligature placement around implants and mandibular premolars and plaque formation. The ligatures were removed after 10 weeks. Microbial samples were obtained using paper points immediately after ligature removal, at 10 and 25 weeks after ligature removal. The microbiological analysis was performed by "checkerboard" DNA-DNA hybridization, including a panel of 16 bacterial species. The amount of bone loss that occurred during the period following ligature removal was significantly larger at implants with a modified surface than at implants with a turned surface and at teeth. The microbiological analysis revealed that the total bacterial load increased during the period following ligature removal and established an anaerobic Gram-negative microflora. It is suggested that the large variation in regard to the microbial profiles makes interpretation of a correlation between disease progression and microbial profiles difficult. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

In-Flight Microbial Monitor

NASA Technical Reports Server (NTRS)

Zeitlin, Nancy; Mullenix, Pamela; Wheeler, Raymond M.; Ruby, Anna Maria

2015-01-01

Previous research has shown that potential human pathogens have been detected on the International Space Station (ISS). New microorganisms are introduced with every exchange of crew and cargo. Microorganisms introduced to the ISS are readily transferred between crew and subsystems (i.e., ECLSS, environmental control and life support systems). Current microbial characterization methods require a culture-based enrichment of microorganisms and at least a 48-hour incubation time. This increases the microbial load while detecting only a limited number of microorganisms. The culture-based method detects approximately 1-10% of the total organisms present and provides no identification. To identify and enumerate ISS samples requires that the microbes be returned to Earth for complete analysis. Therefore, a more expedient, low-cost, inflight method of microbial detection, identification, and enumeration is needed. The RAZOR EX, a ruggedized, commercial off the shelf, real-time PCR field instrument was tested for its ability to detect microorganisms at low concentrations within one hour. Escherichia coli, Salmonella enterica Typhimurium, and Pseudomonas aeruginosa were detected at low levels using real-time DNA amplification. Total heterotrophic counts could also be detected using a 16S gene marker that can identify up to 98% of all bacteria. To reflect viable cells found in the samples, RNA was also detectable using a modified, single-step reverse transcription reaction.

Microbial degradation of Cold Lake Blend and Western Canadian select dilbits by freshwater enrichments.

PubMed

Deshpande, Ruta S; Sundaravadivelu, Devi; Techtmann, Stephen; Conmy, Robyn N; Santo Domingo, Jorge W; Campo, Pablo

2018-06-15

Treatability experiments were conducted to determine the biodegradation of diluted bitumen (dilbit) at 5 and 25 °C for 72 and 60 days, respectively. Microbial consortia obtained from the Kalamazoo River Enbridge Energy spill site were enriched on dilbit at both 5 (cryo) and 25 (meso) ºC. On every sampling day, triplicates were sacrificed and residual hydrocarbon concentrations (alkanes and polycyclic aromatic hydrocarbons) were determined by GCMS/MS. The composition and relative abundance of different bacterial groups were identified by 16S rRNA gene sequencing analysis. While some physicochemical differences were observed between the two dilbits, their biodegradation profiles were similar. The rates and extent of degradation were greater at 25 °C. Both consortia metabolized 99.9% of alkanes; however, the meso consortium was more effective at removing aromatics than the cryo consortium (97.5 vs 70%). Known hydrocarbon-degrading bacteria were present in both consortia (Pseudomonas, Rhodococcus, Hydrogenophaga, Parvibaculum, Arthrobacter, Acidovorax), although their relative abundances depended on the temperatures at which they were enriched. Regardless of the dilbit type, the microbial community structure significantly changed as a response to the diminishing hydrocarbon load. Our results demonstrate that dilbit can be effectively degraded by autochthonous microbial consortia from sites with recent exposure to dilbit contamination. Published by Elsevier B.V.

Quality attributes and microbial storage stability of caviar from cultivated white sturgeon (Acipenser transmontanus).

PubMed

Shin, Joong-Han; Oliveira, Alexandra C M; Rasco, Barbara A

2010-01-01

Caviar was prepared from white sturgeon (Acipenser transmontanus) roe by adjusting the water phase salt (WPS) to 4.0% to 6.3% by adding food grade NaCl. Fish were obtained from 2 different farms from the Inland Northwest (N = 5). Salt was absorbed at a different rate and to a different extent by roe from different fish. The lipid content in the fish roe varied from 10.2% to 14.4% (w/w), with palmitic acid and oleic acid being the most abundant saturated and monounsaturated fatty acids present, respectively. The caviar contained high levels of polyunsaturated fatty acids (PUFA) (35% to 37%) with docosahexanoic acid being the most abundant omega-3 long chain fatty acid. There were no significant differences in microbial storage stability for caviars from different fish stored at 3 degrees C. However, for caviar stored at 7 degrees C, there was less growth of Listeria monocytogenes (using a cocktail of ATCC 19114, 7644, 19113 strains) in 2 samples (2B46 and 0F05) until day 20. In 2 other samples (453F and 2519), which had lower initial microbial loads, less overall microbial growth was observed, indicating that culture and harvest practices result in compositional differences between fish, which may impact both product composition and storage stability.

Periodontitis and periimplantitis: one and the same?

PubMed

Meffert, R M

1993-12-01

Research shows that the same anaerobic, gram-negative pathogens are present in the periodontal and implant pocket or crevice. The implants in a partially edentulous case are probably more at risk due to the bacteria being more pathogenic and a seeding mechanism from the tooth pocket to the implant crevice. In the face of a normal microbial flora, retrograde periimplantitis or radiographic bone loss without gingival changes may be due to trauma because of overloading, loading too soon, and/or loading in a lateral direction. Finally, the combination of an infective process (periimplantitis) and noninfective or traumatic process (retrograde periimplantitis) will result in rapid osseous destruction and, possibly, loss of the implant fixture(s).

Microbial and Nutrient Concentration and Load Data During Stormwater Runoff at a Swine Concentrated Animal Feeding Operation in the North Carolina Coastal Plain, 2006-2007

USGS Publications Warehouse

Harden, Stephen L.

2008-01-01

This report summarizes water-quality and hydrologic data collected during 2006-2007 to characterize bacteria and nutrient loads associated with overland runoff and subsurface tile drainage in spray fields at a swine concentrated animal feeding operation. Four monitoring locations were established at the Lizzie Research Site in the North Carolina Coastal Plain Physiographic Province for collecting discharge and water-quality data during stormwater-runoff events. Water stage was measured continuously at each monitoring location. A stage-discharge relation was developed for each site and was used to compute instantaneous discharge values for collected samples. Water-quality samples were collected for five storm events during 2006-2007 for analysis of nutrients and fecal indicator bacteria. Instantaneous loads of nitrite plus nitrate, total coliform, Escherichia coli (E. coli), and enterococci were computed for selected times during the five storm events.

Effect of probiotics (Saccharomyces boulardii) on microbial translocation and inflammation in HIV-treated patients: a double-blind, randomized, placebo-controlled trial.

PubMed

Villar-García, Judit; Hernández, Juan J; Güerri-Fernández, Robert; González, Alicia; Lerma, Elisabet; Guelar, Ana; Saenz, David; Sorlí, Lluisa; Montero, Milagro; Horcajada, Juan P; Knobel Freud, Hernando

2015-03-01

Microbial translocation has been associated with an increase in immune activation and inflammation in HIV infection despite effective highly active antiretroviral therapy. It has been shown that some probiotics have a beneficial effect by reducing intestinal permeability and, consequently, microbial translocation. To assess changes in microbial translocation and inflammation after treatment with probiotics (Saccharomyces boulardii) in HIV-1-infected patients with virologic suppression. A double-blind, randomized, placebo-controlled trial was conducted in 44 nonconsecutive HIV-1-infected patients with viral load of <20 copies per milliliter for at least 2 years. Patients were randomized to oral supplementation with probiotics or placebo during 12 weeks. Markers of microbial translocation (lipopolysaccharide-binding protein [LBP] and soluble CD14), inflammation (interleukin 6 [IL-6], tumor necrosis factor alpha, interferon gamma, high-sensitivity C-reactive protein), and immunological and clinical data were determined before and after the intervention and 3 months after treatment discontinuation. Quantitative variables were compared using the Mann-Whitney U test, and categorical variables were compared using the Fisher exact test. After 12 weeks of treatment, differences between the probiotic arm and the placebo arm were observed in LBP values (-0.30 vs +0.70 pg/mL) and IL-6 (-0.60 vs +0.78 pg/mL). These differences were also noted at 3 months after treatment withdrawal. Qualitative analysis was performed, defining a variable as "decreased" or "increased" from baseline LBP. A significant decrease of LBP at 12 weeks of treatment was observed (57.9% patients in the probiotic group vs 6.2% in the placebo group, P = 0.002). Treatment with S. boulardii decreases microbial translocation (LBP) and inflammation parameters (IL-6) in HIV-1-infected patients with long-term virologic suppression.

Microbial astronauts: assembling microbial communities for advanced life support systems.

PubMed

Roberts, M S; Garland, J L; Mills, A L

2004-02-01

Extension of human habitation into space requires that humans carry with them many of the microorganisms with which they coexist on Earth. The ubiquity of microorganisms in close association with all living things and biogeochemical processes on Earth predicates that they must also play a critical role in maintaining the viability of human life in space. Even though bacterial populations exist as locally adapted ecotypes, the abundance of individuals in microbial species is so large that dispersal is unlikely to be limited by geographical barriers on Earth (i.e., for most environments "everything is everywhere" given enough time). This will not be true for microbial communities in space where local species richness will be relatively low because of sterilization protocols prior to launch and physical barriers between Earth and spacecraft after launch. Although community diversity will be sufficient to sustain ecosystem function at the onset, richness and evenness may decline over time such that biological systems either lose functional potential (e.g., bioreactors may fail to reduce BOD or nitrogen load) or become susceptible to invasion by human-associated microorganisms (pathogens) over time. Research at the John F. Kennedy Space Center has evaluated fundamental properties of microbial diversity and community assembly in prototype bioregenerative systems for NASA Advanced Life Support. Successional trends related to increased niche specialization, including an apparent increase in the proportion of nonculturable types of organisms, have been consistently observed. In addition, the stability of the microbial communities, as defined by their resistance to invasion by human-associated microorganisms, has been correlated to their diversity. Overall, these results reflect the significant challenges ahead for the assembly of stable, functional communities using gnotobiotic approaches, and the need to better define the basic biological principles that define ecosystem processes in the space environment. Copyright 2004 Springer-Verlag

Microbial astronauts: assembling microbial communities for advanced life support systems

NASA Technical Reports Server (NTRS)

Roberts, M. S.; Garland, J. L.; Mills, A. L.

2004-01-01

Extension of human habitation into space requires that humans carry with them many of the microorganisms with which they coexist on Earth. The ubiquity of microorganisms in close association with all living things and biogeochemical processes on Earth predicates that they must also play a critical role in maintaining the viability of human life in space. Even though bacterial populations exist as locally adapted ecotypes, the abundance of individuals in microbial species is so large that dispersal is unlikely to be limited by geographical barriers on Earth (i.e., for most environments "everything is everywhere" given enough time). This will not be true for microbial communities in space where local species richness will be relatively low because of sterilization protocols prior to launch and physical barriers between Earth and spacecraft after launch. Although community diversity will be sufficient to sustain ecosystem function at the onset, richness and evenness may decline over time such that biological systems either lose functional potential (e.g., bioreactors may fail to reduce BOD or nitrogen load) or become susceptible to invasion by human-associated microorganisms (pathogens) over time. Research at the John F. Kennedy Space Center has evaluated fundamental properties of microbial diversity and community assembly in prototype bioregenerative systems for NASA Advanced Life Support. Successional trends related to increased niche specialization, including an apparent increase in the proportion of nonculturable types of organisms, have been consistently observed. In addition, the stability of the microbial communities, as defined by their resistance to invasion by human-associated microorganisms, has been correlated to their diversity. Overall, these results reflect the significant challenges ahead for the assembly of stable, functional communities using gnotobiotic approaches, and the need to better define the basic biological principles that define ecosystem processes in the space environment. Copyright 2004 Springer-Verlag.

Comparison between a moving bed membrane bioreactor and a conventional membrane bioreactor on organic carbon and nitrogen removal.

PubMed

Yang, Shuai; Yang, Fenglin; Fu, Zhimin; Lei, Ruibo

2009-04-01

A membrane bioreactor filled with carriers instead of activated sludge named a moving bed membrane bioreactor (MBMBR) was investigated for simultaneously removing organic carbon and nitrogen in wastewater. Its performance was compared with a conventional membrane bioreactor (CMBR) at various influent COD/TN ratios of 8.9-22.1. The operational parameters were optimized to increase the treatment efficiency. COD removal efficiency averaged at 95.6% and 96.2%, respectively, for MBMBR and CMBR during the 4 months experimental period. The MBMBR system demonstrated good performance on nitrogen removal at different COD/TN ratios. When COD/TN was 8.9 and the total nitrogen (TN) load was 7.58 mg/l h, the TN and ammonium nitrogen removal efficiencies of the MBMBR were maintained over 70.0% and 80.0%, respectively, and the removed total nitrogen (TN) load reached to 5.31 mg/l h. Multifunctional microbial reactions in the carrier, such as simultaneous nitrification and denitrification (SND), play important roles in nitrogen removal. In comparison, the CMBR did not perform so well. Its TN removal was not stable, and the removed total nitrogen (TN) load was only 1.02 mg/l h at COD/TN ratio 8.9. The specific oxygen utilization rate (SOUR) showed that the biofilm has a better microbial activity than an activated sludge. Nevertheless, the membrane fouling behavior was more severe in the MBMBR than in the CMBR due to a thick and dense cake layer formed on the membrane surface, which was speculated to be caused by the filamentous bacteria in the MBMBR.

Dynamic electrical reconfiguration for improved capacitor charging in microbial fuel cell stacks

NASA Astrophysics Data System (ADS)

Papaharalabos, George; Greenman, John; Stinchcombe, Andrew; Horsfield, Ian; Melhuish, Chris; Ieropoulos, Ioannis

2014-12-01

A microbial fuel cell (MFC) is a bioelectrochemical device that uses anaerobic bacteria to convert chemical energy locked in biomass into small amounts of electricity. One viable way of increasing energy extraction is by stacking multiple MFC units and exploiting the available electrical configurations for increasing the current or stepping up the voltage. The present study illustrates how a real-time electrical reconfiguration of MFCs in a stack, halves the time required to charge a capacitor (load) and achieves 35% higher current generation compared to a fixed electrical configuration. This is accomplished by progressively switching in-parallel elements to in-series units in the stack, thus maintaining an optimum potential difference between the stack and the capacitor, which in turn allows for a higher energy transfer.

Comparison of the impacts of acid and nitrogen additions on carbon fluxes in European conifer and broadleaf forests.

PubMed

Oulehle, Filip; Tahovská, Karolina; Chuman, Tomáš; Evans, Chris D; Hruška, Jakub; Růžek, Michal; Bárta, Jiří

2018-07-01

Increased reactive nitrogen (N) loadings to terrestrial ecosystems are believed to have positive effects on ecosystem carbon (C) sequestration. Global "hot spots" of N deposition are often associated with currently or formerly high deposition of sulphur (S); C fluxes in these regions might therefore not be responding solely to N loading, and could be undergoing transient change as S inputs change. In a four-year, two-forest stand (mature Norway spruce and European beech) replicated field experiment involving acidity manipulation (sulphuric acid addition), N addition (NH 4 NO 3 ) and combined treatments, we tested the extent to which altered soil solution acidity or/and soil N availability affected the concentration of soil dissolved organic carbon (DOC), soil respiration (Rs), microbial community characteristics (respiration, biomass, fungi and bacteria abundances) and enzyme activity. We demonstrated a large and consistent suppression of soil water DOC concentration driven by chemical changes associated with increased hydrogen ion concentrations under acid treatments, independent of forest type. Soil respiration was suppressed by sulphuric acid addition in the spruce forest, accompanied by reduced microbial biomass, increased fungal:bacterial ratios and increased C to N enzyme ratios. We did not observe equivalent effects of sulphuric acid treatments on Rs in the beech forest, where microbial activity appeared to be more tightly linked to N acquisition. The only changes in C cycling following N addition were increased C to N enzyme ratios, with no impact on C fluxes (either Rs or DOC). We conclude that C accumulation previously attributed solely to N deposition could be partly attributable to their simultaneous acidification. Copyright © 2018 Elsevier Ltd. All rights reserved.

Microbial Diversity and Parasitic Load in Tropical Fish of Different Environmental Conditions

PubMed Central

Theisen, Stefan; Abdul-Aziz, Muslihudeen A.; Mrotzek, Grit; Palm, Harry W.; Saluz, Hans Peter

2016-01-01

In this study we analysed fecal bacterial communities and parasites of three important Indonesian fish species, Epinephelus fuscoguttatus, Epinephelus sexfasciatus and Atule mate. We then compared the biodiversity of bacterial communities and parasites of these three fish species collected in highly polluted Jakarta Bay with those collected in less polluted Indonesian areas of Cilacap (E. sexfasciatus, A. mate) and Thousand Islands (E. fuscoguttatus). In addition, E. fuscoguttatus from net cages in an open water mariculture facility was compared with free living E. fuscoguttatus from its surroundings. Both core and shared microbiomes were investigated. Our results reveal that, while the core microbiomes of all three fish species were composed of fairly the same classes of bacteria, the proportions of these bacterial classes strongly varied. The microbial composition of phylogenetically distant fish species, i.e. A. mate and E. sexfasciatus from Jakarta Bay and Cilacap were more closely related than the microbial composition of more phylogentically closer species, i.e. E. fuscoguttatus, E. sexfasciatus from Jakarta Bay, Cilacap and Thousand Islands. In addition, we detected a weak negative correlation between the load of selected bacterial pathogens, i.e. Vibrio sp. and Photobacterium sp. and the number of endoparasites. In the case of Flavobacterium sp. the opposite was observed, i.e. a weak positive correlation. Of the three recorded pathogenic bacterial genera, Vibrio sp. was commonly found in E. fuscoguttatus from mariculture, and lessly in the vicinity of the net cages and rarely in the fishes from the heavily polluted waters from Jakarta Bay. Flavobacterium sp. showed higher counts in mariculture fish and Photobacteria sp. was the most prominent in fish inside and close to the net cages. PMID:27018789

Sediment filtration can reduce the N load of the waste water discharge - a full-scale lake experiment

NASA Astrophysics Data System (ADS)

Aalto, Sanni L.; Saarenheimo, Jatta; Karvinen, Anu; Rissanen, Antti J.; Ropponen, Janne; Juntunen, Janne; Tiirola, Marja

2016-04-01

European commission has obliged Baltic states to reduce nitrate load, which requires high investments on the nitrate removal processes and may increase emissions of greenhouse gases, e.g. N2O, in the waste water treatment plants. We used ecosystem-scale experimental approach to test a novel sediment filtration method for economical waste water N removal in Lake Keurusselkä, Finland between 2014 and 2015. By spatially optimizing the waste water discharge, the contact area and time of nitrified waste water with the reducing microbes of the sediment was increased. This was expected to enhance microbial-driven N transformation and to alter microbial community composition. We utilized 15N isotope pairing technique to follow changes in the actual and potential denitrification rates, nitrous oxide formation and dissimilatory nitrate reduction to ammonium (DNRA) in the lake sediments receiving nitrate-rich waste water input and in the control site. In addition, we investigated the connections between observed process rates and microbial community composition and functioning by using next generation sequencing and quantitative PCR. Furthermore, we estimated the effect of sediment filtration method on waste water contact time with sediment using the 3D hydrodynamic model. We sampled one year before the full-scale experiment and observed strong seasonal patterns in the process rates, which reflects the seasonal variation in the temperature-related mixing patterns of the waste water within the lake. During the experiment, we found that spatial optimization enhanced both actual and potential denitrification rates of the sediment. Furthermore, it did not significantly promote N2O emissions, or N retention through DNRA. Overall, our results indicate that sediment filtration can be utilized as a supplemental or even alternative method for the waste water N removal.

Characterization of the Active Microbiotas Associated with Honey Bees Reveals Healthier and Broader Communities when Colonies are Genetically Diverse

PubMed Central

Mattila, Heather R.; Rios, Daniela; Walker-Sperling, Victoria E.; Roeselers, Guus; Newton, Irene L. G.

2012-01-01

Recent losses of honey bee colonies have led to increased interest in the microbial communities that are associated with these important pollinators. A critical function that bacteria perform for their honey bee hosts, but one that is poorly understood, is the transformation of worker-collected pollen into bee bread, a nutritious food product that can be stored for long periods in colonies. We used 16S rRNA pyrosequencing to comprehensively characterize in genetically diverse and genetically uniform colonies the active bacterial communities that are found on honey bees, in their digestive tracts, and in bee bread. This method provided insights that have not been revealed by past studies into the content and benefits of honey bee-associated microbial communities. Colony microbiotas differed substantially between sampling environments and were dominated by several anaerobic bacterial genera never before associated with honey bees, but renowned for their use by humans to ferment food. Colonies with genetically diverse populations of workers, a result of the highly promiscuous mating behavior of queens, benefited from greater microbial diversity, reduced pathogen loads, and increased abundance of putatively helpful bacteria, particularly species from the potentially probiotic genus Bifidobacterium. Across all colonies, Bifidobacterium activity was negatively correlated with the activity of genera that include pathogenic microbes; this relationship suggests a possible target for understanding whether microbes provide protective benefits to honey bees. Within-colony diversity shapes microbiotas associated with honey bees in ways that may have important repercussions for colony function and health. Our findings illuminate the importance of honey bee-bacteria symbioses and examine their intersection with nutrition, pathogen load, and genetic diversity, factors that are considered key to understanding honey bee decline. PMID:22427917

Factors Influencing Bacterial Diversity and Community Composition in Municipal Drinking Waters in the Ohio River Basin, USA

PubMed Central

Stanish, Lee F.; Hull, Natalie M.; Robertson, Charles E.; Harris, J. Kirk; Stevens, Mark J.; Spear, John R.; Pace, Norman R.

2016-01-01

The composition and metabolic activities of microbes in drinking water distribution systems can affect water quality and distribution system integrity. In order to understand regional variations in drinking water microbiology in the upper Ohio River watershed, the chemical and microbiological constituents of 17 municipal distribution systems were assessed. While sporadic variations were observed, the microbial diversity was generally dominated by fewer than 10 taxa, and was driven by the amount of disinfectant residual in the water. Overall, Mycobacterium spp. (Actinobacteria), MLE1-12 (phylum Cyanobacteria), Methylobacterium spp., and sphingomonads were the dominant taxa. Shifts in community composition from Alphaproteobacteria and Betaproteobacteria to Firmicutes and Gammaproteobacteria were associated with higher residual chlorine. Alpha- and beta-diversity were higher in systems with higher chlorine loads, which may reflect changes in the ecological processes structuring the communities under different levels of oxidative stress. These results expand the assessment of microbial diversity in municipal distribution systems and demonstrate the value of considering ecological theory to understand the processes controlling microbial makeup. Such understanding may inform the management of municipal drinking water resources. PMID:27362708

Biogas production from spent rose hips (Rosa canina L.): fraction separation, organic loading and co-digestion with N-rich microbial biomass.

PubMed

Osojnik Črnivec, Ilja Gasan; Muri, Petra; Djinović, Petar; Pintar, Albin

2014-11-01

Complex waste streams originating from extraction processes containing residual organic solvents and increased C/N ratios have not yet been considered as feedstock for biogas production to a great extent. In this study, spent rosehip (Rosa canina L.) solid residue (64%VS, 22 MJ/kg HHV, 30C/1N) was obtained from an industrial ethanol aided extraction process, and extensively examined in an automated batch bioreactor system for biogas production. Fraction separation of the compact lignocellulosic seeds increased the available sugar and ethanol content, resulting in high biogas potential of the sieved residue (516 NL/kg VS'). In co-digestion of spent rosehip substrate with non-deactivated nitrogen rich microbial co-substrates, methanogenesis was favored (Y(m) > 68%(CH4)). In individual digestion of microbial co-substrates, this was not the case, as biogas with 28 vol.% N2 was produced from activated sludge supplement. Therefore, effective inhibition of exogenous microbiota was achieved in the presence of carbonaceous spent rose hip. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effect of feeding mode and dilution on the performance and microbial community population in anaerobic digestion of food waste.

PubMed

Park, Jong-Hun; Kumar, Gopalakrishnan; Yun, Yeo-Myeong; Kwon, Joong-Chun; Kim, Sang-Hyoun

2018-01-01

The effect of feeding mode and dilution was studied in anaerobic digestion of food waste. An upflow anaerobic digester with a settler was fed at six different organic loading rates (OLRs) from 4.6 to 8.6kgCOD/m 3 /d for 200days. The highest methane productivity of 2.78LCH 4 /L/d was achieved at 8.6kgCOD/m 3 /d during continuous feeding of diluted FW. Continuous feeding of diluted food waste showed more stable and efficient performance than stepwise feeding of undiluted food waste. Sharp increase in propionate concentration attributed towards deterioration of the digester performances in stepwise feeding of undiluted food waste. Microbial communities at various OLRs divulged that the microbial distribution in the continuous feeding of diluted food waste was not significantly perturbed despite the increase of OLR up to 8.6kgCOD/m 3 /d, which was contrast to the unstable distribution in stepwise feeding of undiluted food waste at 6.1kgCOD/m 3 /d. Copyright © 2017 Elsevier Ltd. All rights reserved.

Optimization of liquid fermentation of microbial consortium WSD-5 followed by saccharification and acidification of wheat straw.

PubMed

Wen, Boting; Yuan, Xufeng; Cao, Yanzhuan; Liu, Yan; Wang, Xiaofen; Cui, Zongjun

2012-08-01

The microbial consortium WSD-5 is composed of bacteria and fungi, and the cooperation and symbiosis of the contained microbes enhance the degradation ability of WSD-5. Experiment results showed that the highest cellulase and hemicellulase were obtained when ventilation volume was 4 L/min, stirring rate was 0 rpm, and substrate loading rate was 3%. After 6 days of cultivation, a 67.60% loss in wheat straw dry weight was observed. The crude enzyme secreted from WSD-5 after optimization was evaluated by experiments of saccharification and acidification. The maximum concentration of reducing sugars was 3254 mg/L after 48 h saccharification. The concentration of sCOD peaked on day 2 with a value of 4345 mg/L during acidification, and the biogas yield and methane yield were 22.3% and 32.3% higher than un-acidified samples. This study is the first attempt to explore both the saccharification and the acidification ability of crude enzymes secreted by microbial consortium. Copyright © 2012 Elsevier Ltd. All rights reserved.

A Multi-Omics Approach to Evaluate the Quality of Milk Whey Used in Ricotta Cheese Production

PubMed Central

Sattin, Eleonora; Andreani, Nadia A.; Carraro, Lisa; Lucchini, Rosaria; Fasolato, Luca; Telatin, Andrea; Balzan, Stefania; Novelli, Enrico; Simionati, Barbara; Cardazzo, Barbara

2016-01-01

In the past, milk whey was only a by-product of cheese production, but currently, it has a high commercial value for use in the food industries. However, the regulation of whey management (i.e., storage and hygienic properties) has not been updated, and as a consequence, its microbiological quality is very challenging for food safety. The Next Generation Sequencing (NGS) technique was applied to several whey samples used for Ricotta production to evaluate the microbial community composition in depth using both RNA and DNA as templates for NGS library construction. Whey samples demonstrating a high microbial and aerobic spore load contained mostly Firmicutes; although variable, some samples contained a relevant amount of Gammaproteobacteria. Several lots of whey acquired as raw material for Ricotta production presented defective organoleptic properties. To define the volatile compounds in normal and defective whey samples, a headspace gas chromatography/mass spectrometry (GC/MS) analysis was conducted. The statistical analysis demonstrated that different microbial communities resulted from DNA or cDNA library sequencing, and distinguishable microbiota composed the communities contained in the organoleptic-defective whey samples. PMID:27582735

Shelf-life extension of semi-dried buckwheat noodles by the combination of aqueous ozone treatment and modified atmosphere packaging.

PubMed

Bai, Yi-Peng; Guo, Xiao-Nao; Zhu, Ke-Xue; Zhou, Hui-Ming

2017-12-15

The present study investigated the combined effects of aqueous ozone treatment and modified atmosphere packaging (MAP) on prolonging the shelf-life of semi-dried buckwheat noodles [SBWN; moisture content (22.5±0.5%)] at 25°C. Firstly, the different concentrations of ozonated water were used to make SBWN. Subsequently, SBWN prepared with ozonated water were packaged under six different conditions and stored for 11days. Changes in microbial, chemical-physical, textural properties and sensorial qualities of SWBN were monitored during storage. Microbiological results indicated that adopting 2.21mg/L of ozonated water resulted in a 1.8 log 10 CFU/g reduction of the initial microbial loads in SBWN. In addition, MAP suppressed the microbial growth with a concomitant reduction in the rates of acidification and quality deteriorations of SBWN. Finally, the shelf-life of sample packed under N 2 :CO 2 =30:70 was extended to 9days, meanwhile textural and sensorial characteristics were maintained during the whole storage period. Copyright © 2017 Elsevier Ltd. All rights reserved.

Comparing the short and long term stability of biodegradable, ceramic and cation exchange membranes in microbial fuel cells.

PubMed

Winfield, Jonathan; Chambers, Lily D; Rossiter, Jonathan; Ieropoulos, Ioannis

2013-11-01

The long and short-term stability of two porous dependent ion exchange materials; starch-based compostable bags (BioBag) and ceramic, were compared to commercially available cation exchange membrane (CEM) in microbial fuel cells. Using bi-directional polarisation methods, CEM exhibited power overshoot during the forward sweep followed by significant power decline over the reverse sweep (38%). The porous membranes displayed no power overshoot with comparably smaller drops in power during the reverse sweep (ceramic 8%, BioBag 5.5%). The total internal resistance at maximum power increased by 64% for CEM compared to 4% (ceramic) and 6% (BioBag). Under fixed external resistive loads, CEM exhibited steeper pH reductions than the porous membranes. Despite its limited lifetime, the BioBag proved an efficient material for a stable microbial environment until failing after 8 months, due to natural degradation. These findings highlight porous separators as ideal candidates for advancing MFC technology in terms of cost and operation stability. Copyright © 2013 Elsevier Ltd. All rights reserved.

Factors Influencing Bacterial Diversity and Community Composition in Municipal Drinking Waters in the Ohio River Basin, USA.

PubMed

Stanish, Lee F; Hull, Natalie M; Robertson, Charles E; Harris, J Kirk; Stevens, Mark J; Spear, John R; Pace, Norman R

2016-01-01

The composition and metabolic activities of microbes in drinking water distribution systems can affect water quality and distribution system integrity. In order to understand regional variations in drinking water microbiology in the upper Ohio River watershed, the chemical and microbiological constituents of 17 municipal distribution systems were assessed. While sporadic variations were observed, the microbial diversity was generally dominated by fewer than 10 taxa, and was driven by the amount of disinfectant residual in the water. Overall, Mycobacterium spp. (Actinobacteria), MLE1-12 (phylum Cyanobacteria), Methylobacterium spp., and sphingomonads were the dominant taxa. Shifts in community composition from Alphaproteobacteria and Betaproteobacteria to Firmicutes and Gammaproteobacteria were associated with higher residual chlorine. Alpha- and beta-diversity were higher in systems with higher chlorine loads, which may reflect changes in the ecological processes structuring the communities under different levels of oxidative stress. These results expand the assessment of microbial diversity in municipal distribution systems and demonstrate the value of considering ecological theory to understand the processes controlling microbial makeup. Such understanding may inform the management of municipal drinking water resources.

Non-microbial sources of microbial volatile organic compounds.

PubMed

Choi, Hyunok; Schmidbauer, Norbert; Bornehag, Carl-Gustaf

2016-07-01

The question regarding the true sources of the purported microbial volatile organic compounds (MVOCs) remains unanswered. To identify microbial, as well as non-microbial sources of 28 compounds, which are commonly accepted as microbial VOCs (i.e. primary outcome of interest is Σ 28 VOCs). In a cross-sectional investigation of 390 homes, six building inspectors assessed water/mold damage, took air and dust samples, and measured environmental conditions (i.e., absolute humidity (AH, g/m(3)), temperature (°C), ventilation rate (ACH)). The air sample was analyzed for volatile organic compounds (μg/m(3)) and; dust samples were analyzed for total viable fungal concentration (CFU/g) and six phthalates (mg/g dust). Four benchmark variables of the underlying sources were defined as highest quartile categories of: 1) the total concentration of 17 propylene glycol and propylene glycol ethers (Σ17 PGEs) in the air sample; 2) 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate (TMPD-MIB) in the air sample; 3) semi-quantitative mold index; and 4) total fungal load (CFU/g). Within severely damp homes, co-occurrence of the highest quartile concentration of either Σ17 PGEs or TMPD-MIB were respectively associated with a significantly higher median concentration of Σ 28 VOCs (8.05 and 13.38μg/m(3), respectively) compared to the reference homes (4.30 and 4.86μg/m(3), respectively, both Ps ≤0.002). Furthermore, the homes within the highest quartile range for Σ fungal load as well as AH were associated with a significantly increased median Σ 28 VOCs compared to the reference group (8.74 vs. 4.32μg/m(3), P=0.001). Within the final model of multiple indoor sources on Σ 28 VOCs, one natural log-unit increase in summed concentration of Σ17 PGEs, plus TMPD-MIB (Σ 17 PGEs + TMPD-MIB) was associated with 1.8-times (95% CI, 1.3-2.5), greater likelihood of having a highest quartile of Σ 28 VOCs, after adjusting for absolute humidity, history of repainting at least one room, ventilation rate, and mold index (P-value =0.001). Homes deemed severely mold damaged (i.e., mold index =1) were associated with 1.7-times (95% CI, 0.8-3.6), greater likelihood of having a highest quartile of Σ 28 VOCs, even though such likelihood was not significant (P-value =0.164). In addition, absolute humidity appeared to positively interact with mold index to significantly elevate the prevalence of the highest quartile category of Σ 28 VOCs. The indoor concentration of Σ 28 VOCs, which are widely accepted as MVOCs, are significantly associated with the markers of synthetic (i.e. Σ17 PGEs and TMPD-MIB), and to less extent, microbial (i.e., mold index) sources. Copyright © 2016 Elsevier Inc. All rights reserved.

Wrinkle structures—a critical review

NASA Astrophysics Data System (ADS)

Porada, Hubertus; Bouougri, El Hafid

2007-04-01

In this paper, a variety of so-called 'wrinkle structures' is reviewed in an attempt to help distinguish between crinkly decorations arising from physical processes that acted on siliciclastic bedding surfaces, and true microbially induced 'wrinkle structures'. Two types of small-scale, microbially induced sedimentary structures are prominent due to their distinct geometry and mode of occurrence: (1) 'elephant skin' textures, characterized by reticulate patterns of sharp-crested ridges forming mm- to cm-scale polygons, occurring on argillite or argillaceous veneers above fine-grained sandstone and likely reflecting growth structures of microbial, mats (2) 'Kinneyia' structures, characterized by mm-scale flat-topped, winding ridges and intervening troughs and pits, sometimes resembling small-scale interference ripples. 'Kinneyia' structures usually occur on upper surfaces of siltstone/sandstone beds, themselves frequently event deposits, and are thought to have formed beneath microbial mats. Additionally, more linear variations of mat growth structures, partly resembling small-scale 'α-petees' may be developed. Finally, some wrinkly structures resulting from tractional mat deformation or mat slumping are occasionally preserved. These may appear as arcuate belts of non-penetrative, small-scale folds or as wrinkled bulges on otherwise flat surfaces. 'Wrinkle structures' as indicators for the former presence of mats gain in importance if other mat-related structures are additionally observed in the same clastic succession, e.g. 'sand chips' (sandy intraclasts) or spindle-shaped or sinuously curved to circular sand cracks, frequently combined in networks. Furthermore, appropriate lithologies and facies are required. For instance, if compared with the distribution of modern cohesive microbial mats, laminated siltstone/argillite with intercalated siltstone/sandstone beds representing event deposits in tidal flat successions would be compatible with microbial mat development. Within a variety of physically induced small-scale wrinkly structures, miniature load structures may, above all, be misinterpreted as microbially induced 'wrinkle structures', due to their similar size and appearance, and their comparatively frequent occurrence.

Soil nutrients and microbial activity after early and late season prescribed burns in a Sierra Nevada mixed conifer forest

Treesearch

Sarah T. Hamman; Ingrid C. Burke; Eric E. Knapp

2008-01-01

Restoring the natural fire regime to forested systems that have experienced fire exclusion throughout the past century can be a challenge due to the heavy fuel loading conditions. Fire is being re-introduced to mixed conifer forests in the Sierra Nevada through both early season and late season prescribed burns, even though most fires historically occurred in the late...

Microbe Detector

NASA Technical Reports Server (NTRS)

1985-01-01

Under NASA contracts, McDonnell Douglas developed a microbial load monitor to detect bacterial contamination. Vitek Systems, Inc., a subsidiary, was created to commercialize the product for analyzing body fluids. With the AutoMicrobic System, infections may be treated more quickly. The process involves injecting the fluid into identification cards and screening the reaction. Antibiotic treatments are also suggested. Time in hospital and human error is reduced. There are also possible industrial and environmental applications.

RESEARCH FOR MANAGING URBAN WATERSHED MICROBIAL CONTAMINATION (PROJECT 1: MANAGING URBAN WATERSHED PATHOGEN CONTAMINATION: 2. EFFECT OF LAND USE AND SEASON ON MICROORGANISM CONCENTRATION ON URBAN STORMWATER RUNOFF; 3. MICROORGANISM DIE-OFF RATES UNDER VARIOUS CONDITIONS.

EPA Science Inventory

The Water Supply and Water Resources Division (WSWRD) developed a document entitled Managing Urban Watershed Pathogen Contamination (EPA 600/R-03/111). This document provides information to support specific steps of the total maximum daily load (TMDL) process for meeting water q...

Short communication: Microbial quality of raw milk following commercial long-distance hauling.

PubMed

Darchuk, Emily M; Meunier-Goddik, Lisbeth; Waite-Cusic, Joy

2015-12-01

Hauling is a critical part of the commercial milk supply chain, yet very few studies have aimed to understand its effect on raw milk quality. This study focused on the effect of extended-duration tanker use during hauling on raw milk quality at a commercial facility. Standard tanker use [cleaned-in-place (CIP) once per 24h] served as a control and an incremental between-load water rinse with sanitizer treatment (RS) was evaluated to mitigate any effect from extended duration hauling. During this study, 1 commercial truck with 2 trailers was monitored for 10d. The truck collected milk at a large dairy farm, transported the milk to a manufacturing facility, and then returned to the same farm for a second load. Each round-trip journey took between 10 and 12h, allowing for 2 loads per 24-h use period. Following the second delivery, the truck was cleaned by CIP treatment starting a new treatment day. Producer samples were collected from the raw milk bulk tank on the farm before loading milk into the tanker. The same milk was sampled directly out of the tanker truck before unloading at the manufacturer. Effect on individual bacteria count, thermophilic spore count, and preliminary incubation count was quantified through common industry tests. Surface sponge swabs were also used to monitor tanker sanitation and the efficacy of cleaning treatments. Results did not identify a negative effect on raw milk quality due to extended duration hauling. Whereas the addition of RS did not provide any measurable quality benefits for the microbial milk quality, swab results demonstrated that the RS treatment was able to reduce surface bacteria in the tanker, although not to the same level as the full CIP treatment. Based on this study, current CIP practices for long distance milk hauling appear to be effective in mitigating any measurable effect on raw milk quality. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Biodegradation of airborne acetone/styrene mixtures in a bubble column reactor.

PubMed

Vanek, T; Silva, A; Halecky, M; Paca, J; Ruzickova, I; Kozliak, E; Jones, K

2017-07-29

The ability of a bubble column reactor (BCR) to biodegrade a mixture of styrene and acetone vapors was evaluated to determine the factors limiting the process efficiency, with a particular emphasis on the presence of degradation intermediates and oxygen levels. The results obtained under varied loadings and ratios were matched with the dissolved oxygen levels and kinetics of oxygen mass transfer, which was assessed by determination of k L a coefficients. A 1.5-L laboratory-scale BCR was operated under a constant air flow of 1.0 L.min -1 , using a defined mixed microbial population as a biocatalyst. Maximum values of elimination capacities/maximum overall specific degradation rates of 75.5 gC.m -3 .h -1 /0.197 gC.gdw -1 .h -1 , 66.0 gC.m -3 .h -1 /0.059 gC.gdw -1 .h -1 , and 45.8 gC.m -3 .h -1 /0.027 gC.gdw -1 .h -1 were observed for styrene/acetone 2:1, styrene-rich and acetone-rich mixtures, respectively, indicating significant substrate interactions and rate limitation by biological factors. The BCR removed both acetone and styrene near-quantitatively up to a relatively high organic load of 50 g.m -3 .h -1 . From this point, the removal efficiencies declined under increasing loading rates, accompanied by a significant drop in the dissolved oxygen concentration, showing a process transition to oxygen-limited conditions. However, the relatively efficient pollutant removal from air continued, due to significant oxygen mass transfer, up to a threshold loading rate when the accumulation of acetone and degradation intermediates in the aqueous medium became significant. These observations demonstrate that oxygen availability is the limiting factor for efficient pollutant degradation and that accumulation of intermediates may serve as an indicator of oxygen limitation. Microbial (activated sludge) analyses revealed the presence of amoebae and active nematodes that were not affected by variations in operational conditions.

Effect of edible chitosan/clove oil films and high-pressure processing on the microbiological shelf life of trout fillets.

PubMed

Albertos, Irene; Rico, Daniel; Diez, Ana María; González-Arnáiz, Lucía; García-Casas, María Jesús; Jaime, Isabel

2015-11-01

The inhibitory effect of chitosan films with clove oil (0-50 g kg(-1) ) was evaluated on a range of ten representative food spoilage and pathogenic bacteria. The most sensitive bacteria to the films was Shewanella putrefaciens and the most resistant was Aeromonas hydrophila (inhibition was apparent only at 50 g kg(-1) clove essential oil (CEO)). Films with 20 g kg(-1) CEO inhibited nine of ten of the bacteria tested. Chitosan films with 20 g kg(-1) CEO were combined with high-pressure (HPP) processing as treatments for trout fillets, and changes in physicochemical parameters and microbial load were evaluated at 4 °C over 22 days of storage. The films reduced weight loss and water activity compared to fresh and treated samples (HPP and cooking). Results showed that microbial load (total aerobic mesophilic, lactic acid bacteria and total coliform) of the trout fillets covered with chitosan films was lower than that for HPP-treated samples, and similar to cooked samples, except for coliform counts. The use of 20 g kg(-1) CEO-chitosan films showed a further improvement in the shelf-life of trout fillets when compared to that obtained with HPP and cooking treatment. © 2014 Society of Chemical Industry.

Effect of microbial activities on stored raw buffalo hide.

PubMed

Shede, P N; Kanekar, P P; Polkade, A V; Sarnaik, S S; Dhakephalkar, P K; Chiplonkar, S A; Nilegaonkar, S S

2009-11-01

'Keeping qualities' of hides are dependent on the total microbial flora associated with the hides and the biochemical changes brought about by these microorganisms during short-term storage at ambient temperature (28 +/- 2 degrees C). It was evident that within first 24 hr of hide's ambient storage, bacterial load was raised to 8.8 log cfu g(-1) hide from 6.1 log cfu g(-1) hide. Nonlinear parabolic increase in release of hydroxyproline and tyrosine from stored hide was observed starting from 0 hr and confirming proteolytic activities. Continuous release of CO2 from the stored hide suggested its mineralization. Exponential release of free fatty acids during storage indicated simultaneous lipolysis. Thus the process of biodegradation during the course of ambient storage of hide piece was found to progress steadily and seems to be interrelated as well as very complex. During the storage period, the liquefaction of hide piece was also observed visually within 96 hr. Present studies of assessment of bacterial activities on hide with respect to total bacterial load, release of amino acids, free fatty acids and evolved CO2 provide data that can be used to formulate and evaluate hide curing agent(s) other than salt, thus rendering leather industry a platform to design bio-based technologies for efficient and ecofriendly preservation of raw materials.

Cathodic and anodic biofilms in Single Chamber Microbial Fuel Cells.

PubMed

Cristiani, P; Carvalho, M L; Guerrini, E; Daghio, M; Santoro, C; Li, B

2013-08-01

The oxygen reduction due to microaerophilic biofilms grown on graphite cathodes (biocathodes) in Single Chamber Microbial Fuel Cells (SCMFCs) is proved and analysed in this paper. Pt-free cathode performances are compared with those of different platinum-loaded cathodes, before and after the biofilm growth. Membraneless SCMFCs were operating in batch-mode, filled with wastewater. A substrate (fuel) of sodium acetate (0.03 M) was periodically added and the experiment lasted more than six months. A maximum of power densities, up to 0.5 W m(-2), were reached when biofilms developed on the electrodes and the cathodic potential decreased (open circuit potential of 50-200 mV vs. SHE). The power output was almost constant with an acetate concentration of 0.01-0.05 M and it fell down when the pH of the media exceeded 9.5, independently of the Pt-free/Pt-loading at the cathodes. Current densities varied in the range of 1-5 Am(-2) (cathode area of 5 cm(2)). Quasi-stationary polarization curves performed with a three-electrode configuration on cathodic and anodic electrodes showed that the anodic overpotential, more than the cathodic one, may limit the current density in the SCMFCs for a long-term operation. Copyright © 2012 Elsevier B.V. All rights reserved.

Sampled-time control of a microbial fuel cell stack

NASA Astrophysics Data System (ADS)

Boghani, Hitesh C.; Dinsdale, Richard M.; Guwy, Alan J.; Premier, Giuliano C.

2017-07-01

Research into microbial fuel cells (MFCs) has reached the point where cubic metre-scale systems and stacks are being built and tested. Apart from performance enhancement through catalysis, materials and design, an important research area for industrial applicability is stack control, which can enhance MFCs stack power output. An MFC stack is controlled using a sampled-time digital control strategy, which has the advantage of intermittent operation with consequent power saving, and when used in a hybrid series stack connectivity, can avoid voltage reversals. A MFC stack comprising four tubular MFCs was operated hydraulically in series. Each MFC was connected to an independent controller and the stack was connected electrically in series, creating a hybrid-series connectivity. The voltage of each MFC in the stack was controlled such that the overall series stack voltage generated was the algebraic sum (1.26 V) of the individual MFC voltages (0.32, 0.32, 0.32 and 0.3). The controllers were able to control the individual voltages to the point where 2.52 mA was drawn from the stack at a load of 499.9 Ω (delivering 3.18 mW). The controllers were able to reject the disturbances and perturbations caused by electrical loading, temperature and substrate concentration.

A Tuneable Switch for Controlling Environmental Degradation of Bioplastics: Addition of Isothiazolinone to Polyhydroxyalkanoates

PubMed Central

Woolnough, Catherine Anne; Yee, Lachlan Hartley; Charlton, Timothy Stuart; Foster, Leslie John Ray

2013-01-01

Controlling the environmental degradation of polyhydroxybutyrate (PHB) and polyhydroxyvalerate (P(HB-co-HV)) bioplastics would expand the range of their potential applications. Combining PHB and P(HB-co-HV) films with the anti-fouling agent 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOI, <10% w/w) restricted microbial colonisation in soil, but did not significantly affect melting temperature or the tensile strength of films. DCOI films showed reduced biofouling and postponed the onset of weight loss by up to 100 days, a 10-fold increase compared to unmodified films where the microbial coverage was significant. In addition, the rate of PHA-DCOI weight loss, post-onset, reduced by about 150%; in contrast a recorded weight loss of only 0.05% per day for P(HB-co-HV) with a 10% DCOI loading was observed. This is in stark contrast to the unmodified PHB film, where a recorded weight loss of only 0.75% per day was made. The ‘switch’ that initiates film weight loss, and its subsequent reduced rate, depended on the DCOI loading to control biofouling. The control of biofouling and environmental degradation for these DCOI modified bioplastics increases their potential use in biodegradable applications. PMID:24146779

The effect of oregano essential oil on microbial load and sensory attributes of dried meat.

PubMed

Hernández, Helga; Fraňková, Adéla; Sýkora, Tomáš; Klouček, Pavel; Kouřimská, Lenka; Kučerová, Iva; Banout, Jan

2017-01-01

Microbial load can be controlled using either synthetic or natural preservatives. Particular interest has been focused on the potential application of plant essential oils as safer additives for meat. However, there is no published research on the use of essential oils during the meat drying process. This study was focused on enhancing the meat drying process by using oregano essential oil (OEO) to inhibit the growth of bacteria and thus obtain a value-added dried meat product. The sensory response from assessors is presented. It was found that the application of OEO in meat was effective in inhibiting Salmonella enteritidis and Escherichia coli. After 6 h of drying at 55 °C, 2 mL (0.038 mL L -1 air) and 1.5 mL (0.028 mL L -1 air) of OEO were considered as the minimal inhibitory concentrations (MICs) against S. enteritidis and E. coli respectively. Samples treated with 0.75 mL of OEO were more attractive for consumption compared with the control; at a higher concentration of OEO, the sensory quality of the food was affected. A value-added dried meat product obtained by using OEO to enhance food safety received an acceptable sensory response from consumers. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Nitrification denitrification enhanced biological phosphorous removal (NDEBPR) occurs in a lab-scale alternating hypoxic/oxic membrane bioreactor.

PubMed

Sibag, Mark; Kim, Han-Seung

2012-01-01

Strict anaerobic or anoxic maintenance of the system and process susceptibility to low organic loading are major concerns in nitrification denitrification enhanced biological phosphorous removal (NDEBPR). The study has initiated NDEBPR in a lab-scale alternating hypoxic/oxic membrane bioreactor by developing an enhanced mixed microbial culture capable of removing 97±2% COD, 99±0.84% NH(3)-N, 90±3% TN, and 96±1% TP-PO(4)(3-) with 20-day SRT. The viable cells ranging from 1.6×10(8) to 2.0×10(8)cells/ml estimated from the total bacterial genomic DNA (6.43-7.83 μg DNA/ml) represented only 5% of the MLVSS indicating low microbial biomass concentration. Reducing the organic load from 1250 to 750 mg COD/ml as glucose did not deteriorate the effluent quality (3.77±1.0 mg N-TN/l; 0.08±0.24 mg NH(3)-N/l; and 0.32±0.10 mg PO(4)(3-)-P/l). These observations are characteristics of activated sludge that harbors denitrifying polyphosphate accumulating organisms (DPAOs). The results showed that NDEBPR can be achieved under alternating hypoxic/oxic conditions. Copyright © 2011 Elsevier Ltd. All rights reserved.

Nitrogen cycling processes and microbial community composition in bed sediments in the Yukon River at Pilot Station

USGS Publications Warehouse

Repert, Deborah A.; Underwood, Jennifer C.; Smith, Richard L.; Song, Bongkeun

2014-01-01

Information on the contribution of nitrogen (N)-cycling processes in bed sediments to river nutrient fluxes in large northern latitude river systems is limited. This study examined the relationship between N-cycling processes in bed sediments and N speciation and loading in the Yukon River near its mouth at the Bering Sea. We conducted laboratory bioassays to measure N-cycling processes in sediment samples collected over distinct water cycle seasons. In conjunction, the microbial community composition in the bed sediments using genes involved in N-cycling (narG, napA, nosZ, and amoA) and 16S rRNA gene pyrosequences was examined. Temporal variation was observed in net N mineralization, nitrate uptake, and denitrification rate potentials and correlated strongly with sediment carbon (C) and extractable N content and microbial community composition rather than with river water nutrient concentrations. The C content of the bed sediment was notably impacted by the spring flood, ranging from 1.1% in the midst of an ice-jam to 0.1% immediately after ice-out, suggesting a buildup of organic material (OM) prior to scouring of the bed sediments during ice break up. The dominant members of the microbial community that explained differences in N-processing rates belonged to the genera Crenothrix,Flavobacterium, and the family of Comamonadaceae. Our results suggest that biogeochemical processing rates in the bed sediments appear to be more coupled to hydrology, nutrient availability in the sediments, and microbial community composition rather than river nutrient concentrations at Pilot Station.

Optimization of supercritical carbon dioxide treatment for the inactivation of the natural microbial flora in cubed cooked ham.

PubMed

Ferrentino, Giovanna; Balzan, Sara; Spilimbergo, Sara

2013-02-15

This study aims to investigate the effects of supercritical carbon dioxide (SC-CO₂) treatment on the inactivation of the natural microbial flora in cubed cooked ham. Response surface methodology with a central composite design was applied to determine the optimal process conditions and investigate the effect of three independent variables (pressure, temperature and treatment time). Additionally, analyses of texture, pH and color together with a storage study of the product were performed to determine its microbial and qualitative stability. Response surface analysis revealed that 12 MPa, 50 °C, 5 min were the optimal conditions to obtain about 3.0, 1.6, and 2.5 Log(CFU/g) reductions of mesophilic aerobic bacteria, psychrophilic bacteria and lactic acid bacteria respectively. Inactivation to undetectable levels of yeasts and molds and coliforms was also obtained. A storage study of 30 days at 4 °C was carried out on the treated product (12 MPa, 50 °C, 5 min) monitoring microbial growth, pH, texture, and color parameters (L*, a*, b* and ΔE). Microbial loads slightly increased and after 30 days of storage reached the same levels detected in the fresh product. Color parameters (L*, a*, b*) showed slight variations while pH and texture did not change significantly. On the basis of the results obtained, SC-CO₂ can be considered a promising technique to microbiologically stabilize cubed cooked ham and, in general, cut/sliced meat products without affecting its quality attributes. Copyright © 2012 Elsevier B.V. All rights reserved.

Characterization of Serpentine Samples from the Coast Range Ophiolite Microbial Observatory with μ-FTIR and XRD. ­­

NASA Astrophysics Data System (ADS)

Sousa, A.; Cardace, D.

2017-12-01

Serpentinizing systems hold much promise as potentially habitable environments in diverse planetary settings. They involve abundant and simple ingredients (i.e., the mineral olivine, liquid water), support subsurface microbial communities on Earth (Crespo-Medina et al. 2014; Suzuki et al. 2014; Kelley et al. 2005) and are thought to occur elsewhere in our solar system such as Mars (Schulte et al. 2006; Ehlmann et al. 2010)and possibly ocean worlds (Waite et al. 2017; Vance 2009). Although geochemical and microbial data collection continues in serpentinizing systems, the identification and resolution of potential biosignatures in serpentinites are not yet clear. Specifically, the micro-scale mineralogical contexts in which cell fragments or biofilm residues may be formed and preserved is lacking. Here we report preliminary transmission and reflection mode μ-FTIR spectral maps and XRD diffractograms, obtained with instruments relevant to robotic exploration missions (Blake et al. 2012; Igisu et al. 2009; Leroi et al. 2009). Samples analyzed include ultramafic rock and constituent mineral standards (e.g., olivine) and rocks collected from near surface sites associated with the NASA Astrobiology Institute-funded initiative, the Coast Range Ophiolite Microbial Observatory (CROMO), in Lower Lake, CA (Cardace et al. 2013). These new results provide co-registered, complementary data on astrobiologically important rock and mineral phases related to serpentinization (Crespo-Medina et al. 2014; Twing et al. 2017). Future work will leverage this data set in microbial colonization experiments aimed at parsing background organic loads in serpentinites from surficial/fracture-localized modern biofilm signatures.

The influence of processing on the microbial risk associated with Rooibos (Aspalathus linearis) tea.

PubMed

Gouws, Pieter; Hartel, Toni; van Wyk, Rudean

2014-12-01

This review discusses the influence of processing on the microbial risk associated with Salmonella in Rooibos tea, the identification of Salmonella and preventative and control measures to control microbial contamination. Rooibos tea, like other plant products, naturally contains a high microbial load. Downstream processing steps of these products usually help in reducing any contaminants present. Due to the delicate flavour properties and nature of Rooibos, gentle processing techniques are necessary for the production of good quality tea. However, this has a major influence on the microbiological status of the product. The presence of Salmonella in Rooibos is poorly understood. The ubiquitous distribution of Salmonella in the natural environment and its prevalence in the global food chain, the physiological adaptability, virulence of the bacterial pathogen and its serious economic impact on the food industry, emphasises the need for continued awareness and stringent controls at all levels of food production. With the advances of technology and information at hand, the processing of Rooibos needs to be re-evaluated. Since the delicate nature of Rooibos prohibits the use of harsh methods to control Salmonella, alternative methods for the steam pasteurisation of Rooibos show great potential to control Salmonella in a fast, efficient and cost-effective manner. These alternative methods will significantly improve the microbiological quality of Rooibos and provide a product that is safe to consumers. © 2014 Society of Chemical Industry.

Gamma irradiation of sorghum flour: Effects on microbial inactivation, amylase activity, fermentability, viscosity and starch granule structure

NASA Astrophysics Data System (ADS)

Mukisa, Ivan M.; Muyanja, Charles M. B. K.; Byaruhanga, Yusuf B.; Schüller, Reidar B.; Langsrud, Thor; Narvhus, Judith A.

2012-03-01

Malted and un-malted sorghum ( Sorghum bicolor (L.) Moench) flour was gamma irradiated with a dose of 10 kGy and then re-irradiated with 25 kGy. The effects of irradiation on microbial decontamination, amylase activity, fermentability (using an amylolytic L. plantarum MNC 21 strain), starch granule structure and viscosity were determined. Standard methods were used during determinations. The 10 kGy dose had no effect on microbial load of un-malted flour but reduced that of malted flour by 3 log cycles. Re-irradiation resulted in complete decontamination. Irradiation of malt caused a significant ( p<0.05) reduction in alpha and beta amylase activity (22% and 32%, respectively). Irradiation of un-malted flour increased the rates of utilization of glucose and maltose by 53% and 100%, respectively, during fermentation. However, microbial growth, rate of lactic acid production, final lactic acid concentration and pH were not affected. Starch granules appeared normal externally even after re-irradiation, however, granules ruptured and dissolved easily after hydration and gelatinization. Production of high dry matter density porridge (200 g dry matter/L) with a viscosity of 3500 cP was achieved by irradiation of un-malted flout at 10 kGy. Gamma irradiation can be used to decontaminate flours and could be utilized to produce weaning porridge from sorghum.

Inflight Microbial Monitoring- An Alternative Method to Culture Based Detection Currently Used on the International Space Station

NASA Technical Reports Server (NTRS)

Khodadad, Christina L.; Birmele, Michele N.; Roman, Monsi; Hummerick, Mary E.; Smith, David J.; Wheeler, Raymond M.

2015-01-01

Previous research has shown that potentially destructive microorganisms and human pathogens have been detected on the International Space Station (ISS). The likelihood of introducing new microorganisms occurs with every exchange of crew or addition of equipment or supplies. Microorganisms introduced to the ISS are readily transferred between crew and subsystems (i.e. ECLSS, environmental control and life support systems). Current microbial characterization methods require enrichment of microorganisms and at least a 48-hour incubation time. This increases the microbial load while detecting only a limited number of the total microorganisms. The culture based method detects approximately 1-10% of the total organisms present and provides no identification. To identify and enumerate ISS microbes requires that samples be returned to Earth for complete analysis. Therefore, a more expedient, low-cost, in-flight method of microbial detection, identification, and enumeration is warranted. The RAZOR EX, a ruggedized, commercial off the shelf, real-time PCR field instrument was tested for its ability to detect microorganisms at low concentrations within one hour. Escherichia coli, Salmonella enterica Typhimurium, and Pseudomonas aeruginosa were detected at low levels using real-time DNA amplification. Total heterotrophic counts could also be detected using a 16S gene marker that can identify up to 98% of all bacteria. To reflect viable cells found in the samples, RNA was also detectable using a modified, single-step reverse transcription reaction.

Inflight Microbial Monitoring-An Alternative Method to Culture Based Detection Currently Used on International Space Station

NASA Technical Reports Server (NTRS)

Khodadad, Christina L.; Birmele, Michele N.; Roman, Monsi; Hummerick, Mary E.; Smith, David J.; Wheeler, Raymond M.

2015-01-01

Previous research has shown that microorganisms and potential human pathogens have been detected on the International Space Station (ISS). The potential to introduce new microorganisms occurs with every exchange of crew or addition of equipment or supplies. Previous research has shown that microorganisms introduced to the ISS are readily transferred between crew and subsystems and back (i.e. ECLSS, environmental control and life support systems). Current microbial characterization methods require enrichment of microorganisms and a 48-hour incubation time. This increases the microbial load while detecting a limited number of microorganisms. The culture based method detects approximately 1-10% of the total organisms present and provides no identification, To identify and enumerate ISS samples requires that samples to be returned to Earth for complete analysis. Therefore, a more expedient, low-cost, in-flight method of microbial detection, identification, and enumeration is warranted. The RAZOR EX, a ruggedized, commercial off the shelf, real-time PCR field instrument was tested for its ability to detect microorganism at low concentrations within one hour. Escherichia coli, Salmonella enterica Typhimurium, and Pseudomonas aeruginosa were detected at low levels using real-time DNA amplification. Total heterotrophic counts could also be detected using a 16S gene marker that can identify up to 98% of all bacteria. To reflect viable cells found in the samples, RNA was also detectable using a modified, single-step reverse transcription reaction.

Air-cathode microbial fuel cell array: a device for identifying and characterizing electrochemically active microbes.

PubMed

Hou, Huijie; Li, Lei; de Figueiredo, Paul; Han, Arum

2011-01-15

Microbial fuel cells (MFCs) have generated excitement in environmental and bioenergy communities due to their potential for coupling wastewater treatment with energy generation and powering diverse devices. The pursuit of strategies such as improving microbial cultivation practices and optimizing MFC devices has increased power generating capacities of MFCs. However, surprisingly few microbial species with electrochemical activity in MFCs have been identified because current devices do not support parallel analyses or high throughput screening. We have recently demonstrated the feasibility of using advanced microfabrication methods to fabricate an MFC microarray. Here, we extend these studies by demonstrating a microfabricated air-cathode MFC array system. The system contains 24 individual air-cathode MFCs integrated onto a single chip. The device enables the direct and parallel comparison of different microbes loaded onto the array. Environmental samples were used to validate the utility of the air-cathode MFC array system and two previously identified isolates, 7Ca (Shewanella sp.) and 3C (Arthrobacter sp.), were shown to display enhanced electrochemical activities of 2.69 mW/m(2) and 1.86 mW/m(2), respectively. Experiments using a large scale conventional air-cathode MFC validated these findings. The parallel air-cathode MFC array system demonstrated here is expected to promote and accelerate the discovery and characterization of electrochemically active microbes. Copyright © 2010 Elsevier B.V. All rights reserved.

Planetary quarantine

NASA Technical Reports Server (NTRS)

1971-01-01

Methods for presterilization cleaning or decontamination of spacecraft hardware to reduce microbial load, without harming materials or spacecraft components, are investigated. Three methods were considered: (1) chemicals in liquid form, relying on physical removal as well as bacterial or bacteriostatic action; (2) chemicals used in the gaseous phase, relying on bacterial activity; and (3) mechanical cleaning relying on physical removal of organisms. These methods were evaluated in terms of their effectiveness in microbial burden reduction and compatibility with spacecraft hardware. Results show chemical methods were effective against spore microorganisms but were harmful to spacecraft materials. Mechanical methods were also effective with the degree depending upon the type of instrument employed. Mechanical methods caused problems in handling the equipment, due to vacuum pressure damaging the very thin layered materials used for shielding, and the bristles used in the process caused streaks or abrasions on some spacecraft components.

Microbial dynamics during industrial rearing, processing, and storage of the tropical house cricket (Gryllodes sigillatus) for human consumption.

PubMed

Vandeweyer, Dries; Wynants, Enya; Crauwels, Sam; Verreth, Christel; Viaene, Nikolaas; Claes, Johan; Lievens, Bart; Van Campenhout, Leen

2018-04-06

In this study, the microbiota during industrial rearing, processing, and storage of the edible tropical house cricket, Gryllodes sigillatus , was investigated. To this end, samples were analyzed of the cricket feed, before feeding as well as taken from the cages, and the crickets during rearing, after harvest, and after processing into frozen, oven-dried, and smoked and subsequently oven-dried end products. Although the feed contained lower microbial numbers than the crickets, both were dominated by the same species-level operational taxonomic units as determined by Illumina Miseq sequencing. They corresponded, among others, to members of Porphyromonadaceae, Fusobacterium , Parabacteroides and Erwinia The harvested crickets contained high microbial numbers, but none of the investigated food pathogens Salmonella spp., Listeria monocytogenes , Bacillus cereus , and coagulase-positive staphylococci. However, some possible mycotoxin-producing fungi were isolated from the crickets. A post-harvest heat treatment, shortly boiling the crickets, reduced microbial numbers, but an endospore load of 2.4 log cfu/g remained. After processing, an increase in microbial counts was observed for dried and smoked plus dried crickets. Additionally, in the smoked plus dried crickets, a high abundance of a Bacillus sp. was observed. Considering the possible occurrence of food-pathogenic species from this genus, it is advised to apply a heat treatment which is sufficient to eliminate spores. Nevertheless, the microbial numbers remained constant over a six-month storage period, frozen (frozen end product) or at ambient temperature (oven-dried and smoked plus dried end products). Importance. The need for sustainable protein sources has led to the emergence of a new food sector, producing and processing edible insects into foods. However, insight into the microbial quality of this new food and into the microbial dynamics during rearing, processing and storage of edible insects is still limited. Samples monitored for their microbiota were obtained in this study from an industrial rearing and processing cycle. The results lead in the first place to the identification of process steps which are critical for microbial food safety. Secondly, they can be used in the construction of a HACCP plan and of a Novel Food dossier which is required in Europe for edible insects. Finally, they confirm the shelf life period which was determined by the rearer. Copyright © 2018 American Society for Microbiology.

Behind the Scenes: Patient Safety in the Operating Room and Central Materiel Service During Deployments

DTIC Science & Technology

2005-01-01

The surgical hand scrub plays a significant role in preventing nosocomial and surgical site infections . After approval from the Infection Control...stressful conditions in a time- constrained environment. As a result, they are more comfortable with the hands - on aspects of patient care within the...amount of dust, organic debris, and microbial load in surgical environments. Proper cleaning of surfaces can greatly reduce the risk of nosocomial

Removal of trace organic chemicals in onsite wastewater soil treatment units: a laboratory experiment.

PubMed

Teerlink, Jennifer; Martínez-Hernández, Virtudes; Higgins, Christopher P; Drewes, Jörg E

2012-10-15

Onsite wastewater treatment is used by 20% of residences in the United States. The ability of these systems, specifically soil treatment units (STUs), to attenuate trace organic chemicals (TOrCs) is not well understood. TOrCs released by STUs pose a potential risk to downstream groundwater and hydraulically-connected surface water that may be used as a drinking water source. A series of bench-scale experiments were conducted using sand columns to represent STUs and to evaluate the efficacy of TOrC attenuation as a function of hydraulic loading rate (1, 4, 8, 12, and 30 cm/day). Each hydraulic loading rate was examined using triplicate experimental columns. Columns were initially seeded with raw wastewater to establish a microbial community, after which they were fed with synthetic wastewater and spiked with 17 TOrCs, in four equal doses per day, to provide a consistent influent water quality. After an initial start-up phase, effluent from all columns consistently demonstrated >90% reductions in dissolved organic carbon and nearly complete (>85%) oxidation of ammonia to nitrate, comparable to the performance of field STUs. The results of this study suggest STUs are capable of attenuating many TOrCs present in domestic wastewater, but attenuation is compound-specific. A subset of TOrCs exhibited an inverse relationship with hydraulic loading rate and attenuation efficiency. Atenolol, cimetidine, and TCPP were more effectively attenuated over time in each experiment, suggesting that the microbial community evolved to a stage where these TOrCs were more effectively biotransformed. Aerobic conditions as compared to anaerobic conditions resulted in more efficient attenuation of acetaminophen and cimetidine. Copyright © 2012. Published by Elsevier Ltd.

Ammonia threshold for inhibition of anaerobic digestion of thin stillage and the importance of organic loading rate.

PubMed

Moestedt, Jan; Müller, Bettina; Westerholm, Maria; Schnürer, Anna

2016-03-01

Biogas production from nitrogen-rich feedstock results in release of ammonia (NH3), causing inhibition of the microbial process. The reported threshold ammonia value for stable biogas production varies greatly between studies, probably because of differences in operating conditions. Moreover, it is often difficult to separate the effect of ammonia inhibition from that of organic loading rate (OLR), as these two factors are often interrelated. This study attempted to distinguish the effects of ammonia and OLR by analysis of two laboratory-scale biogas reactors operating with thin stillage and subjected to an increase in free ammonia (from 0.30 to 1.1 g L(-1)) either by addition of an external nitrogen source (urea) or by increasing the OLR (3.2-6.0 g volatile solids L(-1) d(-1)). The results showed that ammonia concentration was detrimental for process performance, with the threshold for stability in both processes identified as being about 1 g NH3-N L(-1), irrespective of OLR. Analysis of the methanogenic community showed limited differences between the two reactors on order level and a clear increase in the abundance of Methanomicrobiales, particularly Methanoculleus sp., in response to increasing ammonia concentration. Further comprehensive molecular analysis revealed that diverse Methanoculleus species dominated in the reactors at a given ammonia level at different OLR. The acetogenic community was clearly affected by both ammonia concentration and OLR, suggesting that the volatile fatty acid load in relation to the higher OLR was important for the dynamics of this community. © 2015 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Effect of cleaning and disinfection of toys on infectious diseases and micro-organisms in daycare nurseries.

PubMed

Ibfelt, T; Engelund, E H; Schultz, A C; Andersen, L P

2015-02-01

The rising number of children in daycare nurseries increases opportunities for the transmission of infectious diseases. Pathogens may be transmitted directly from child to child via sneezing, coughing and touching, or indirectly via the environment. Toys are among the fomites with the highest pathogen load, but their role in disease transmission is unknown. To determine if washing and disinfection of toys can reduce sickness absence and microbial pathogen load in the nursery environment. Twelve nurseries (caring for 587 children) were randomized to intervention and control groups. The intervention consisted of washing and disinfection of toys and linen every two weeks for three months by a commercial cleaning company. The extent and causes of sickness absence among the children were recorded in both groups before and after introduction of the intervention. Ten sampling points in each nursery were examined for bacteria and respiratory viruses. The presence of respiratory virus DNA/RNA was widespread, but very few pathogenic bacteria were found in the environment. The intervention reduced the presence of adenovirus [odds ratio (OR) 2.4, 95% confidence interval (CI) 1.1-5.0], rhinovirus (OR 5.3, 95% CI 2.3-12.4) and respiratory syncytial virus (OR 4.1, 95% CI 1.5-11.2) compared with the control group, but the intervention had no effect on sickness absence or disease patterns in the nurseries. Although cleaning and disinfection of toys every two weeks can decrease the microbial load in nurseries, it does not appear to reduce sickness absence among nursery children. Copyright © 2014 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

The effect of feed water dissolved organic carbon concentration and composition on organic micropollutant removal and microbial diversity in soil columns simulating river bank filtration.

PubMed

Bertelkamp, C; van der Hoek, J P; Schoutteten, K; Hulpiau, L; Vanhaecke, L; Vanden Bussche, J; Cabo, A J; Callewaert, C; Boon, N; Löwenberg, J; Singhal, N; Verliefde, A R D

2016-02-01

This study investigated organic micropollutant (OMP) biodegradation rates in laboratory-scale soil columns simulating river bank filtration (RBF) processes. The dosed OMP mixture consisted of 11 pharmaceuticals, 6 herbicides, 2 insecticides and 1 solvent. Columns were filled with soil from a RBF site and were fed with four different organic carbon fractions (hydrophilic, hydrophobic, transphilic and river water organic matter (RWOM)). Additionally, the effect of a short-term OMP/dissolved organic carbon (DOC) shock-load (e.g. quadrupling the OMP concentrations and doubling the DOC concentration) on OMP biodegradation rates was investigated to assess the resilience of RBF systems. The results obtained in this study imply that - in contrast to what is observed for managed aquifer recharge systems operating on wastewater effluent - OMP biodegradation rates are not affected by the type of organic carbon fraction fed to the soil column, in case of stable operation. No effect of a short-term DOC shock-load on OMP biodegradation rates between the different organic carbon fractions was observed. This means that the RBF site simulated in this study is resilient towards transient higher DOC concentrations in the river water. However, a temporary OMP shock-load affected OMP biodegradation rates observed for the columns fed with the river water organic matter (RWOM) and the hydrophilic fraction of the river water organic matter. These different biodegradation rates did not correlate with any of the parameters investigated in this study (cellular adenosine triphosphate (cATP), DOC removal, specific ultraviolet absorbance (SUVA), richness/evenness of the soil microbial population or OMP category (hydrophobicity/charge). Copyright © 2015 Elsevier Ltd. All rights reserved.

Microbial biodiversity, quality and shelf life of microfiltered and pasteurized extended shelf life (ESL) milk from Germany, Austria and Switzerland.

PubMed

Schmidt, Verena S J; Kaufmann, Veronika; Kulozik, Ulrich; Scherer, Siegfried; Wenning, Mareike

2012-03-01

Information on factors limiting the shelf life of extended shelf life (ESL) milk produced by microfiltration and subsequent pasteurization is very limited. In this study, three different batches of ESL milk were analyzed at different stages of the production process and during storage at 4 °C, 8 °C and 10 °C in order to evaluate the changes in bacterial cell counts, microbial diversity and enzymatic quality. Additionally, detailed biodiversity analyses of 250 retail ESL milk packages produced by five manufacturers in Germany, Austria and Switzerland were performed at the end of shelf life. It was observed that microfiltration decreased the microbial loads by 5-6 log₁₀ units to lower than 1 CFU/mL. However, bacterial counts at the end of shelf life were extremely variable and ranged between <1 and 8 log₁₀ CFU/mL. 8% of all samples showed spoilage indicated by cell counts higher than 6 log₁₀ CFU/mL. The main spoilage groups of bacteria were Gram-negative post-process recontaminants (Acinetobacter, Chryseobacterium, Psychrobacter, Sphingomonas) and the spore formers Paenibacillus and Bacillus cereus, while other spore formers and Microbacterium spp. did not reach spoilage levels. Paenibacillus spp. and B. cereus apparently influenced enzymatic spoilage, as indicated by increased free fatty acid production, pH 4.6 soluble peptide fractions and off-flavors. In some cases, enzymatic spoilage was observed although microbial counts were well below 6 log₁₀ CFU/mL. Thirteen B. cereus isolates were characterized for their toxin profiles and psychrotolerance. Hbl, nhe, and cytK toxin genes were detected in ten, thirteen, and four isolates, respectively, whereas the ces gene was always absent. Interestingly, only three of the thirteen isolates could be allocated to psychrotolerant genotypes, as indicated by the major cold shock cspA gene signature. Generally, large discrepancies in microbial loads and biodiversity were observed at the end of shelf life, even among packages of the same production batch. We suggest that such unexpected differences may be due to very low cell counts after ESL treatment, causing stochastic variations of initial species distributions in individual packages. This would result in the development of significantly different bacterial populations during cold storage, including the occasional development of high numbers of pathogenic species such as B. cereus or Acinetobacter. Copyright © 2011 Elsevier B.V. All rights reserved.

Chloride retention and release in a boreal forest soil: effects of soil water residence time and nitrogen and chloride loads.

PubMed

Bastviken, David; Sandén, Per; Svensson, Teresia; Ståhlberg, A Carina; Magounakis, Malin; Oberg, Gunilla

2006-05-01

The common assumption that chloride (Cl-) is conservative in soils and can be used as a groundwater tracer is currently being questioned, and an increasing number of studies indicate that Cl- can be retained in soils. We performed lysimeter experiments with soil from a coniferous forest in southeast Sweden to determine whether pore water residence time and nitrogen and Cl- loads affected Cl- retention. Over the first 42 days there was a net retention of Cl- with retention rates averaging 3.1 mg CI- m(-2) d(-1) (68% of the added Cl- retained over 42 days). Thereafter, a net release of Cl- at similar rates was observed for the remaining experimental period (85 d). Longer soil water residence time and higher Cl- load gave higher initial retention and subsequent release rates than shorter residence time and lower Cl- load did. Nitrogen load did not affect Cl transformation rates. This study indicates that simultaneous retention and release of Cl- can occur in soils, and that rates may be considerable relative to the load. The retention of Cl- observed was probably due to chlorination of soil organic matter or ion exchange. The cause of the shift between net retention and net release is unclear, but we hypothesize that the presence of O2 or the presence of microbially available organic matter regulates Cl- retention and release rates.

Biofiltration of high loads of ethyl acetate in the presence of toluene.

PubMed

Deshusses, M; Johnson, C T; Leson, G

1999-08-01

To date, biofilters have been used primarily to control dilute, usually odorous, off-gases with relatively low volatile organic compound (VOC) concentrations (< 1 g m-3) and VOC loads (< 50 g m-3 hr-1). Recently, however, U.S. industry has shown an interest in applying biofilters to higher concentrations of VOCs and hazardous air pollutants (HAPs). In this study, the behavior of biofilters under high loads of binary VOC mixtures was studied. Two bench-scale biofilters were operated using a commercially available medium and a mixture of wood chips and compost. Both were exposed to varying mixtures of ethyl acetate and toluene. Concentration profiles and the corresponding removal efficiencies as a function of VOC loading were determined through frequent grab-sampling and GC analysis. Biofilter response to two frequently encountered operating problems--media dry-out and operating temperatures exceeding 40 degrees C--was also evaluated under controlled conditions. Microbial populations were also monitored to confirm the presence of organisms capable of degrading both major off-gas constituents. The results demonstrated several characteristics of biofilters operating under high VOC load conditions. Maximum elimination capacities for ethyl acetate were typically in the range of 200 g m-3 hr-1. Despite the presence of toluene degraders, the removal of toluene was inhibited by high loads of ethyl acetate. Several byproducts, particularly ethanol, were formed. Short-term dry-out and temperature excursions resulted in reduced performance.

Ability of Hand Hygiene Interventions Using Alcohol-Based Hand Sanitizers and Soap To Reduce Microbial Load on Farmworker Hands Soiled during Harvest.

PubMed

de Aceituno, Anna Fabiszewski; Bartz, Faith E; Hodge, Domonique Watson; Shumaker, David J; Grubb, James E; Arbogast, James W; Dávila-Aviña, Jorgé; Venegas, Fabiola; Heredia, Norma; García, Santos; Leon, Juan S

2015-11-01

Effective hand hygiene is essential to prevent the spread of pathogens on produce farms and reduce foodborne illness. The U.S. Food and Drug Administration Food Safety Modernization Act Proposed Rule for Produce Safety recommends the use of soap and running water for hand hygiene of produce handlers. The use of alcohol-based hand sanitizer (ABHS) may be an effective alternative hygiene intervention where access to water is limited. There are no published data on the efficacy of either soap or ABHS-based interventions to reduce microbial contamination in agricultural settings. The goal of this study was to assess the ability of two soap-based (traditional or pumice) and two ABHS-based (label-use or two-step) hygiene interventions to reduce microbes (coliforms, Escherichia coli, and Enterococcus spp.) and soil (absorbance of hand rinsate at 600 nm [A600]) on farmworker hands after harvesting produce, compared with the results for a no-hand-hygiene control. With no hand hygiene, farmworker hands were soiled (median A600, 0.48) and had high concentrations of coliforms (geometric mean, 3.4 log CFU per hand) and Enterococcus spp. (geometric mean, 5.3 log CFU per hand) after 1 to 2 h of harvesting tomatoes. Differences in microbial loads in comparison to the loads in the control group varied by indicator organism and hygiene intervention (0 to 2.3 log CFU per hand). All interventions yielded lower concentrations of Enterococcus spp. and E. coli (P < 0.05), but not of coliforms, than were found in the control group. The two-step ABHS intervention led to significantly lower concentrations of coliforms and Enterococcus spp. than the pumice soap and label-use ABHS interventions (P < 0.05) and was the only intervention to yield significantly fewer samples with E. coli than were found in the control group (P < 0.05). All interventions removed soil from hands (P < 0.05), soap-based interventions more so than ABHS-based interventions (P < 0.05). ABHS-based interventions were equally as effective as hand washing with soap at reducing indicator organisms on farmworker hands. Based on these results, ABHS is an efficacious hand hygiene solution for produce handlers, even on soiled hands.

Nitrogen removal performance and loading capacity of a novel single-stage nitritation-anammox system with syntrophic micro-granules.

PubMed

Wang, Shaopo; Liu, Yuan; Niu, Qigui; Ji, Jiayuan; Hojo, Toshimasa; Li, Yu-You

2017-07-01

The operation performance of a novel micro-granule based syntrophic system of nitritation and anammox was studied by controlling the oxygen concentration and maintaining a constant temperature of 25°C. With the oxygen concentration of around 0.11 (<0.15)mg/L, the single-stage nitritation-anammox system was startup successfully at a nitrogen loading rate (NLR) of 1.5kgN/m 3 /d. The reactor was successfully operated at volumetric N loadings ranging from 0.5 to 2.5kgN/m 3 /d with a high nitrogen removal of 82%. The microbial community was composed by ammonia oxidizing bacteria (AOB) and anammox bacteria forming micro-granules with an average diameter of 0.8mm and good settleability. Results from pyrosequencing analysis revealed that Ca. Kuenenia and Nitrosomonas were selected and enriched in the community over the startup period, and these were identified as the dominant anammox bacteria and AOB species, respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of filler loading and silane modification on the biodegradability of SBR composites reinforced with peanut shell powder

NASA Astrophysics Data System (ADS)

Shaniba, V.; Balan, Aparna K.; Sreejith, M. P.; Jinitha, T. V.; Subair, N.; Purushothaman, E.

2017-06-01

The development of biocomposites and their applications are important in material science due to environmental and sustainability issues. The extent of degradation depends on the nature of reinforcing filler, particle size and their modification. In this article, we tried to focus on the biodegradation of composites of Styrene Butadiene Rubber (SBR) reinforced with Peanut Shell Powder (PSP) by soil burial test. The composites of SBR with untreated PSP (UPSP) and silane modified PSP (SPSP) of 10 parts per hundred rubber (phr) and 20 phr filler loading in two particle size were buried in the garden soil for six months. The microbial degradation were assessed through the measurement of weight loss, tensile strength and hardness at definite period. The study shows that degradation increases with increase in filler loading and particle size. The chemical treatment of filler has been found to resist the degradation. The analysis of morphological properties by the SEM also confirmed biodegradation process by the microorganism in the soil.

The Chaoborus pump: Migrating phantom midge larvae sustain hypolimnetic oxygen deficiency and nutrient internal loading in lakes.

PubMed

Tang, Kam W; Flury, Sabine; Grossart, Hans-Peter; McGinnis, Daniel F

2017-10-01

Hypolimnetic oxygen demand in lakes is often assumed to be driven mainly by sediment microbial processes, while the role of Chaoborus larvae, which are prevalent in eutrophic lakes with hypoxic to anoxic bottoms, has been overlooked. We experimentally measured the respiration rates of C. flavicans at different temperatures yielding a Q 10 of 1.44-1.71 and a respiratory quotient of 0.84-0.98. Applying the experimental data in a system analytical approach, we showed that migrating Chaoborus larvae can significantly add to the water column and sediment oxygen demand, and contribute to the observed linear relationship between water column respiration and depth. The estimated phosphorus excretion by Chaoborus in sediment is comparable in magnitude to the required phosphorus loading for eutrophication. Migrating Chaoborus larvae thereby essentially trap nutrients between the water column and the sediment, and this continuous internal loading of nutrients would delay lake remediation even when external inputs are stopped. Copyright © 2017 Elsevier Ltd. All rights reserved.

Polyox and carrageenan based composite film dressing containing anti-microbial and anti-inflammatory drugs for effective wound healing.

PubMed

Boateng, Joshua S; Pawar, Harshavardhan V; Tetteh, John

2013-01-30

Polyethylene oxide (Polyox) and carrageenan based solvent cast films have been formulated as dressings for drug delivery to wounds. Films plasticised with glycerol were loaded with streptomycin (30%, w/w) and diclofenac (10%, w/w) for enhanced healing effects in chronic wounds. Blank and drug loaded films were characterised by texture analysis (for mechanical and mucoadhesive properties), scanning electron microscopy, differential scanning calorimetry, X-ray diffraction and Fourier transform infrared spectroscopy. In addition, swelling, in vitro drug release and antibacterial studies were conducted to further characterise the films. Both blank and drug loaded films showed a smooth, homogeneous surface morphology, excellent transparency, high elasticity and acceptable tensile (mechanical) properties. The drug loaded films showed a high capacity to absorb simulated wound fluid and significant mucoadhesion force which is expected to allow effective adherence to and protection of the wound. The films showed controlled release of both streptomycin and diclofenac for 72 h. These drug loaded films produced higher zones of inhibition against Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli compared to the individual drugs zones of inhibition. Incorporation of streptomycin can prevent and treat chronic wound infections whereas diclofenac can target the inflammatory phase of wound healing to relieve pain and swelling. Copyright © 2012 Elsevier B.V. All rights reserved.

Microleakage Evaluation at Implant-Abutment Interface Using Radiotracer Technique

PubMed Central

Siadat, Hakimeh; Arshad, Mahnaz; Mahgoli, Hossein-Ali; Fallahi, Babak

2016-01-01

Objectives: Microbial leakage through the implant-abutment (I-A) interface results in bacterial colonization in two-piece implants. The aim of this study was to compare microleakage rates in three types of Replace abutments namely Snappy, GoldAdapt, and customized ceramic using radiotracing. Materials and Methods: Three groups, one for each abutment type, of five implants and one positive and one negative control were considered (a total of 17 regular body implants). A torque of 35 N/cm was applied to the abutments. The samples were immersed in thallium 201 radioisotope solution for 24 hours to let the radiotracers leak through the I-A interface. Then, gamma photons received from the radiotracers were counted using a gamma counter device. In the next phase, cyclic fatigue loading process was applied followed by the same steps of immersion in the radioactive solution and photon counting. Results: Rate of microleakage significantly increased (P≤0.05) in all three types of abutments (i.e. Snappy, GoldAdapt, and ceramic) after cyclic loading. No statistically significant differences were observed between abutment types after cyclic loading. Conclusions: Microleakage significantly increases after cyclic loading in all three Replace abutments (GoldAdapt, Snappy, ceramic). Lowest microleakage before and after cyclic loading was observed in GoldAdapt followed by Snappy and ceramic. PMID:28392814

Research supporting potential modification of the NASA specification for dry heat microbial reduction of spacecraft hardware

NASA Astrophysics Data System (ADS)

Spry, James A.; Beaudet, Robert; Schubert, Wayne

Dry heat microbial reduction (DHMR) is the primary method currently used to reduce the microbial load of spacecraft and component parts to comply with planetary protection re-quirements. However, manufacturing processes often involve heating flight hardware to high temperatures for purposes other than planetary protection DHMR. At present, the specifica-tion in NASA document NPR8020.12, describing the process lethality on B. atrophaeus (ATCC 9372) bacterial spores, does not allow for additional planetary protection bioburden reduction credit for processing outside a narrow temperature, time and humidity window. Our results from a comprehensive multi-year laboratory research effort have generated en-hanced data sets on four aspects of the current specification: time and temperature effects in combination, the effect that humidity has on spore lethality, and the lethality for spores with exceptionally high thermal resistance (so called "hardies"). This paper describes potential modifications to the specification, based on the data set gener-ated in the referenced studies. The proposed modifications are intended to broaden the scope of the current specification while still maintaining confidence in a conservative interpretation of the lethality of the DHMR process on microorganisms.

Truffles decontamination treatment by ionizing radiation

NASA Astrophysics Data System (ADS)

Adamo, M.; Capitani, D.; Mannina, L.; Cristinzio, M.; Ragni, P.; Tata, A.; Coppola, R.

2004-09-01

A research project, funded by the Italian Ministry of Research and the European Union, is in progress aimed to develop processes to enhance, by irradiation, the safety and the wholesomeness of fresh products relevant for Italian food industry. Irradiation was performed on truffles, since the bacterial contamination impairs their trade in foreign countries. The microbial population and the shelf life under refrigeration were studied either on samples untreated or on samples submitted to γ-rays in a 1-2.5 kGy dose range. The effect of the treatment was monitored by UV and NMR techniques. Total microbial population and the shelf life prolongation were investigated. The synergistic effect of the dose, the packaging under vacuum and the storage/irradiation temperature resulted in a direct effect on the microbial load, spoilage and shelf life. After the irradiation, small variations in the intensity of some NMR resonances due to aromatic compounds and other unassigned compounds were observed. As confirmed by UV spectrophotometric data, these phenomena seemed to originate from a small degradation of polyphenols; the induced growth of soluble phenols suggested that the 1.5 kGy dose can be considered as the radiation dose threshold beyond which clear chemical modifications on truffles appear.

Bacteria-Affinity 3D Macroporous Graphene/MWCNTs/Fe3O4 Foams for High-Performance Microbial Fuel Cells.

PubMed

Song, Rong-Bin; Zhao, Cui-E; Jiang, Li-Ping; Abdel-Halim, Essam Sayed; Zhang, Jian-Rong; Zhu, Jun-Jie

2016-06-29

Promoting the performance of microbial fuel cells (MFCs) relies heavily on the structure design and composition tailoring of electrode materials. In this work, three-dimensional (3D) macroporous graphene foams incorporated with intercalated spacer of multiwalled carbon nanotubes (MWCNTs) and bacterial anchor of Fe3O4 nanospheres (named as G/MWCNTs/Fe3O4 foams) were first synthesized and used as anodes for Shewanella-inoculated microbial fuel cells (MFCs). Thanks to the macroporous structure of 3D graphene foams, the expanded electrode surface by MWCNTs spacing, as well as the high affinity of Fe3O4 nanospheres toward Shewanella oneidensis MR-1, the anode exhibited high bacterial loading capability. In addition to spacing graphene nanosheets for accommodating bacterial cells, MWCNTs paved a smoother way for electron transport in the electrode substrate of MFCs. Meanwhile, the embedded bioaffinity Fe3O4 nanospheres capable of preserving the bacterial metabolic activity provided guarantee for the long-term durability of the MFCs. With these merits, the constructed MFC possessed significantly higher power output and stronger stability than that with conventional graphite rod anode.

Study of the microbial ecology of wild and aquacultured Tunisian fresh fish.

PubMed

Boulares, Mouna; Mejri, Lobna; Hassouna, Mnasser

2011-10-01

Eighty samples of fresh fish were collected in Tunisia and analyzed for microbial load. Quality and hygienic safety of the meat and intestines of wild and aquacultured fresh fish were determined. The mesophilic aerobic plate count and populations of psychrotrophic lactic acid bacteria (LAB) and other psychrotrophic bacteria ranged from 5.67 to 7.29, 4.51 to 6, and 5.07 to 6.21 log CFU/g, respectively. For all microbiological determinations, bacterial counts were lower in meat than in the intestines of fresh fish. For all samples lower microbial populations were found in most of the wild fish than in the aquacultured fish. No isolates of the pathogenic genera Salmonella and Listeria were detected in any sample. Among the 160 strains of biopreservative psychrotrophic LAB and the 150 strains of spoilage psychrotrophic gram-negative bacteria identified by biochemical and molecular methods, Lactobacillus (six species) and Pseudomonas (six species) predominated. Lactococcus, Leuconostoc, Carnobacterium (C. piscicola and C. divergens), Aeromonas, and Photobacterium were the most common genera, and Lactococcus lactis, Lactobacillus plantarum, Pseudomonas fluorescens, and Aeromonas hydrophila were the most common species. These findings indicate that the microbiological quality of fresh fish in Tunisia can be preserved by controlling pathogenic and psychrotrophic bacteria.

Opportunistic pathogens and faecal indicators in drinking water associated biofilms in Cluj, Romania.

PubMed

Farkas, A; Drăgan-Bularda, M; Ciatarâş, D; Bocoş, B; Tigan, S

2012-09-01

Biofouling occurs without exception in all water systems, with undesirable effects such as biocorrosion and deterioration of water quality. Drinking water associated biofilms represent a potential risk to human health by harbouring pathogenic or toxin-releasing microorganisms. This is the first study investigating the attached microbiota, with potential threat to human health, in a public water system in Romania. The presence and the seasonal variation of viable faecal indicators and opportunistic pathogens were investigated within naturally developed biofilms in a drinking water treatment plant. Bacterial frequencies were correlated with microbial loads in biofilms as well as with physical and chemical characteristics of biofilms and raw water. The biofilms assessed in the current study proved to be extremely active microbial consortia. High bacterial numbers were recovered by cultivation, including Pseudomonas aeruginosa, Escherichia coli, Aeromonas hydrophila, intestinal enterococci and Clostridium perfringens. There were no Legionella spp. detected in any biofilm sample. Emergence of opportunistic pathogens in biofilms was not significantly affected by the surface material, but by the treatment process. Implementation of a water safety plan encompassing measures to prevent microbial contamination and to control biofouling would be appropriate.

Flume experiments elucidate relationships between microbial genetics, nitrogen species and hydraulics in controlling nitrous oxide production in the hyporheic zone

NASA Astrophysics Data System (ADS)

Quick, A. M.; Farrell, T. B.; Reeder, W. J.; Feris, K. P.; Tonina, D.; Benner, S. G.

2014-12-01

The hyporheic zone is a potentially important producer of nitrous oxide, a powerful greenhouse gas. The location and magnitude of nitrous oxide generation within the hyporheic zone involves complex interactions between multiple nitrogen species, redox conditions, microbial communities, and hydraulics. To better understand nitrous oxide generation and emissions from streams, we conducted large-scale flume experiments in which we monitored pore waters along hyporheic flow paths within stream dune structures. Measured dissolved oxygen, ammonia, nitrate, nitrite, and dissolved nitrous oxide showed distinct spatial relationships reflecting redox changes along flow paths. Denitrifying genes (nosZ, nirS, and nirK), determined using qPCR, were spatially associated with abundances of nitrogen species. Using residence times along a flow path, clear trends in oxygen conditions, genes encoding for microbial catalysis, and nitrogen species were observed. Hotspots of targeted genes correlated with hotspots for conversion of nitrogen species, including nitrous oxide production and conversion to dinitrogen. Trends were apparent regardless of dune size, allowing for the possibility to apply observed relationships to multiple streambed morphologies. Relating streambed morphology and loading of nitrogen species allows for prediction of nitrous oxide production in the hyporheic zone.

Characterization of atmospheric bioaerosols at 9 sites in Tijuana, Mexico

NASA Astrophysics Data System (ADS)

Hurtado, Lilia; Rodríguez, Guillermo; López, Jonathan; Castillo, J. E.; Molina, Luisa; Zavala, Miguel; Quintana, Penelope J. E.

2014-10-01

The atmosphere is not considered a habitat for microorganisms, but can exist in the atmosphere as bioaerosols. These microorganisms in the atmosphere have great environmental importance through their influence on physical processes such as ice nucleation and cloud droplet formation. Pathogenic airborne microorganisms may also have public health consequences. In this paper we analyze the microbial concentration in the air at three sites in Tijuana, Mexico border during the Cal-Mex 2010 air quality campaign and from nine sites over the following year. Samples were collected by impaction with the air analyzer Millipore M Air T, followed by incubation and counting as colony forming units (CFU) of viable colonies. Airborne microbial contamination average levels ranged from a low of 230 ± 130 CFU/m³ in the coastal reference site to an average of 40,100 ± 21,689 CFU/m³ in the Tijuana river valley. We found the highest microbial load in the summer and the lowest values in the winter. Potentially pathogenic bacteria were isolated from the samples, with Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Enterococcus faecalis being most common. This work is the first evaluation of bioaerosols in Tijuana, Mexico.

Microbial Breakdown of Organic Carbon in the Diverse Sediments of Guaymas Basin

NASA Astrophysics Data System (ADS)

Hoarfrost, A.; Snider, R.; Arnosti, C.

2015-12-01

Guaymas Basin is characterized by sediments under conditions ranging from hemipelagic to hydrothermal. This wide range in geochemical contexts results in diverse microbial communities that may have varying abilities to access organic matter. We can address these functional differences by comparing enzyme activities initializing the breakdown of organic matter across these sediment types; however, previous direct measurements of the extracellular hydrolysis of complex organic carbon in sediments are sparse. We measured this first step of heterotrophic processing of organic matter in sediments at 5-10cm and 55-60cm depth from a wide range of environmental settings in Guaymas Basin. Sediment sources included sulfidic seeps on the Sonora Margin, hemipelagic ridge flank sediments, and hydrothermically altered Sonora Margin sediments bordering a methane seep site. Hydrolysis of organic substrates varied by depth and by sediment source, but despite high energy potential and organic carbon load in sulfidic sediments, activity was not highest where hydrothermal influence was highest. These results suggest that heterotrophic breakdown of organic carbon in Guaymas Basin sediments may be sensitive to factors including varying composition of organic carbon available in different sediment types, or differences in microbial community capacities to access specific organic substrates.

Long-term characterization of residential runoff and assessing potential surrogates of fecal indicator organisms.

PubMed

Reano, Dane C; Haver, Darren L; Oki, Lorence R; Yates, Marylynn V

2015-05-01

Investigations into the microbiological impacts of urban runoff on receiving water bodies, especially during storm conditions, have yielded general paradigms that influence runoff abatement and control management strategies. To determine whether these trends are present in other runoff sources, the physical, chemical, and microbiological components of residential runoff from eight neighborhoods in Northern and Southern California were characterized over the course of five years. Sampling occurred regularly and during storm events, resulting in 833 data sets. Analysis of runoff data assisted in characterizing residential runoff, elucidating differences between dry and storm conditions, and identifying surrogates capable of assessing microbiological quality. Results indicate that although microbial loading increases during storm events similar to urban runoff, annual microbial loading in these study sites principally occurs during dry conditions (24% storm, 76% dry). Generated artificial neural network and multiple linear regression models assessed surrogate performance by accurately predicting Escherichia coli concentrations from validation data sets (R(2) = 0.74 and 0.77, respectively), but required input from other fecal indicator organism (FIO) variables to maintain performance (R(2) = 0.27 and 0.18, respectively, without FIO). This long-term analysis of residential runoff highlights characteristics distinct from urban runoff and establishes necessary variables for determining microbiological quality, thus better informing future management strategies. Copyright © 2015 Elsevier Ltd. All rights reserved.

Thermophilic Dry Methane Fermentation of Distillation Residue Eluted from Ethanol Fermentation of Kitchen Waste and Dynamics of Microbial Communities.

PubMed

Huang, Yu-Lian; Tan, Li; Wang, Ting-Ting; Sun, Zhao-Yong; Tang, Yue-Qin; Kida, Kenji

2017-01-01

Thermophilic dry methane fermentation is advantageous for feedstock with high solid content. Distillation residue with 65.1 % moisture content was eluted from ethanol fermentation of kitchen waste and subjected to thermophilic dry methane fermentation, after adjusting the moisture content to 75 %. The effect of carbon to nitrogen (C/N) ratio on thermophilic dry methane fermentation was investigated. Results showed that thermophilic dry methane fermentation could not be stably performed for >10 weeks at a C/N ratio of 12.6 and a volatile total solid (VTS) loading rate of 1 g/kg sludge/d; however, it was stably performed at a C/N ratio of 19.8 and a VTS loading rate of 3 g/kg sludge/d with 83.4 % energy recovery efficiency. Quantitative PCR analysis revealed that the number of bacteria and archaea decreased by two orders of magnitude at a C/N ratio of 12.6, whereas they were not influenced at a C/N ratio of 19.8. Microbial community analysis revealed that the relative abundance of protein-degrading bacteria increased and that of organic acid-oxidizing bacteria and acetic acid-oxidizing bacteria decreased at a C/N ratio of 12.6. Therefore, there was accumulation of NH 4 + and acetic acid, which inhibited thermophilic dry methane fermentation.

Pearl aquaculture-profitable environmental remediation?

PubMed

Gifford, S; Dunstan, R H; O'Connor, W; Roberts, T; Toia, R

2004-02-05

Bivalve molluscs are filter feeders, with pearl oysters able to filter water at rates up to 25 lh(-1)g(-1) of dry wt. tissue. Since this process leads to rapid bioaccumulation of recalcitrant pollutants such as heavy metals, organochlorine pesticides and hydrocarbons from impacted sites, it has prompted the widespread use of molluscs as biomonitors to quantify levels of marine pollution. This paper proposes pearl oyster deployment as a novel bioremediation technology for impacted sites to remove toxic contaminants, reduce nutrient loads and lower concentrations of microbial pathogens. Estimates extrapolated from the literature suggest that a modest pearl oyster farm of 100 t oyster material per year could remove 300 kg heavy metals plus 24 kg of organic contaminants via deposition into the tissue and shell. Furthermore, it was estimated that up to 19 kg of nitrogen may be removed from the coastal ecosystem per tonne of pearl oyster harvested. Pearl oysters are also likely to filter substantial amounts of sewage associated microbial pathogens from the water column. Method of cultivation and site selection are the key to minimising negative environmental impacts of bivalve cultivation. Deployment of oysters at sites with high nutrient and contaminant loadings would be advantageous, as these compounds would be removed from the ecosystem whilst generating a value-added product. Future potential may exist for harvesting bio-concentrated elements for commercial production.

Selection of electrogenic bacteria for microbial fuel cell in removing Victoria blue R from wastewater.

PubMed

Chen, Chih-Yu; Tsai, Teh-Hua; Wu, Pei-Ssu; Tsao, Shuo-En; Huang, Yu-Shan; Chung, Ying-Chien

2018-01-28

This study was conducted to select electrogenic bacteria from wastewater sludge. Phylogenetic analysis revealed that Proteobacteria was the dominant phylum in the microbial fuel cell (MFC) during the decomposition process of organic pollutants. Five culturable bacteria strains - namely, Bacillus subtilis, Flavobacterium sp., Aeromonas hydrophila, Citrobacter freundii, and Stenotrophomonas sp. - have a double potential in dye removal and electricity generation. We inoculated the mixed electrogenic bacteria at a specific ratio and treated them with a triphenylmethane dye, Victoria blue R (VBR), to evaluate their electricity generation ability for the artificial and real wastewater. The results of the VBR shock-loading experiment indicated that the inoculated MFC could adapt to shock loading in 1-2 days and exhibited high removal efficiency (95-100%) for 100-800 mg L -1 VBR with a power density of 8.62 ± 0.10 to 34.81 ± 0.25 mW m -2 . The selected electrogenic bacteria in the MFC could use VBR as only electron donor for power generation. The matrix effects of the real wastewater on VBR removal and electricity generation of MFC were insignificant. VBR degradation by the electrogenic bacteria involves a stepwise demethylation process to yield partially dealkylated VBR species. In addition, these results demonstrate the feasibility of inoculating culturable bacteria strains to develop an efficient MFC for purifying wastewater.

Assessment and Use of Optical Oxygen Sensors as Tools to Assist in Optimal Product Component Selection for the Development of Packs of Ready-to-Eat Mixed Salads and for the Non-Destructive Monitoring of in-Pack Oxygen Levels Using Chilled Storage.

PubMed

Hempel, Andreas W; O'Sullivan, Maurice G; Papkovsky, Dmitri B; Kerry, Joseph P

2013-05-22

Optical oxygen sensors were used to ascertain the level of oxygen consumed by individual salad leaves for optimised packaging of ready-to-eat (RTE) Italian salad mixes during refrigerated storage. Seven commonly found leaves in Italian salad mixes were individually assessed for oxygen utilisation in packs. Each leaf showed varying levels of respiration throughout storage. Using the information obtained, an experimental salad mix was formulated (termed Mix 3) which consisted of the four slowest respiring salad leaves-Escarole, Frisee, Red Batavia, Lollo Rosso. Mix 3 was then compared against two commercially available Italian salads; Mix 1 (Escarole, Frisee, Radicchio, Lollo Rosso) and Mix 2 (Cos, Frisee, Radicchio, Lollo Rosso). Optical sensors were used to non-destructively monitor oxygen usage in all mixes throughout storage. In addition to oxygen consumption, all three salad mixes were quality assessed in terms of microbial load and sensorial acceptability. In conclusion, Mix 3 was found to consume the least amount of oxygen over time, had the lowest microbial load and was most sensorially preferred ( p < 0.05) in terms of overall appearance and acceptability. This study clearly shows the potential that oxygen sensors possess in terms of assisting in the optimised development of commercial RTE salad products.

A novel reusable nanocomposite for complete removal of dyes, heavy metals and microbial load from water based on nanocellulose and silver nano-embedded pebbles.

PubMed

Suman; Kardam, Abhishek; Gera, Meeta; Jain, V K

2015-01-01

The present work proposed a nanocellulose (NC)-silver nanoparticles (AgNPs) embedded pebbles-based composite material as a novel reusable cost-effective water purification device for complete removal of dyes, heavy metals and microbes. NC was prepared using acid hydrolysis of cellulose. The AgNPs were generated in situ using glucose and embedded within the porous concrete pebbles by the technique of inter-diffusion of ion, providing a very strong binding of nanoparticles within the porous pebbles and thus preventing any nanomaterials leaching. Fabrication of a continual running water purifier was achieved by making different layering of NC and Ag nano-embedded pebbles in a glass column. The water purifier exhibited not only excellent dye and heavy metal adsorption capacity, but also long-term antibacterial activity against pathogenic and non-pathogenic bacterial strains. The adsorption mainly occurred through electrostatic interaction and pore diffusion also contributed to the process. The bed column purifier has shown 99.48% Pb(II) and 98.30% Cr(III) removal efficiency along with 99% decontamination of microbial load at an optimum working pH of 6.0. The high adsorption capacity and reusability, with complete removal of dyes, heavy metals and Escherichia coli from the simulated contaminated water of composite material, will provide new opportunities to develop a cost-effective and eco-friendly water purifier for commercial application.

Microbial abundance on the eggs of a passerine bird and related fitness consequences between urban and rural habitats

PubMed Central

Lee, Sang-im; Lee, Hyunna; Jablonski, Piotr G.; Choe, Jae Chun

2017-01-01

Urban environments present novel and challenging habitats to wildlife. In addition to well-known difference in abiotic factors between rural and urban environments, the biotic environment, including microbial fauna, may also differ significantly. In this study, we aimed to compare the change in microbial abundance on eggshells during incubation between urban and rural populations of a passerine bird, the Eurasian Magpie (Pica pica), and examine the consequences of any differences in microbial abundances in terms of hatching success and nestling survival. Using real-time PCR, we quantified the abundances of total bacteria, Escherichia coli/Shigella spp., surfactin-producing Bacillus spp. and Candida albicans on the eggshells of magpies. We found that urban magpie eggs harboured greater abundances of E. coli/Shigella spp. and C. albicans before incubation than rural magpie eggs. During incubation, there was an increase in the total bacterial load, but a decrease in C. albicans on urban eggs relative to rural eggs. Rural eggs showed a greater increase in E. coli/Shigella spp. relative to their urban counterpart. Hatching success of the brood was generally lower in urban than rural population. Nestling survival was differentially related with the eggshell microbial abundance between urban and rural populations, which was speculated to be the result of the difference in the strength of the interaction among the microbes. This is the first demonstration that avian clutches in urban and rural populations differ in eggshell microbial abundance, which can be further related to the difference in hatching success and nestling survival in these two types of environments. We suggest that future studies on the eggshell microbes should investigate the interaction among the microbes, because the incubation and/or environmental factors such as urbanization or climate condition can influence the dynamic interactions among the microbes on the eggshells which can further determine the breeding success of the parents. PMID:28953940

Effects of Variety and Postharvest Handling Practices on Microbial Population at Different Stages of the Value Chain of Fresh Tomato (Solanum lycopersicum) in Western Terai of Nepal.

PubMed

Khadka, Ram B; Marasini, Madan; Rawal, Ranjana; Gautam, Durga M; Acedo, Antonio L

2017-01-01

Background . Fresh vegetables such as tomato should have low microbial population for safe consumption and long storage life. The aerobic bacterial count (ABC) and coliform bacterial count (CBC), yeast, and mold population are the most widely used microbial indicators in fresh vegetables which should be lower than 4 log CFU g -1 for safe consumption. The stages of the supply chain, postharvest handling methods, and crop varieties had significant effects on microbial population. ABC, CBC, yeast, and mold population were significantly highest ( P < 0.05) at retail market (5.59, 4.38, 2.60, and 3.14 log CFU g -1 , resp.), followed by wholesale market (4.72, 4.71, 2.43, and 2.44 log CFU g -1 , resp.), and were least at farm gate (3.89, 3.63, 2.38, and 2.03 log CFU g -1 , resp.). Improved postharvest practices (washing in clean water and grading and packaging in clean plastic crate) helped to reduce ABC, CBC, and mold population by 2.51, 32.70, and 29.86 percentage as compared to the conventional method (no washing and no grading and packaging in mud plastered bamboo baskets). Among varieties, Pusa ruby had the lowest microbial load of 2.58, 4.53, 0.96, and 1.77 log CFU g -1 for ABC, CBC, yeast, and mold count, respectively. Significantly negative correlation ( P < 0.05) was observed between fruit pH & ABC and pH & mold count. Although the microbial quality of fresh tomato is safe in the local market of western Terai of Nepal both in conventional and in improved practices however still it is essential to follow improved postharvest handling practices in production and marketing of newly introduced tomato cultivars (high-pH cultivars) for ensuring the safe availability of fresh tomato in the market.

Physicochemical properties influencing denitrification rate and microbial activity in denitrification bioreactors

NASA Astrophysics Data System (ADS)

Schmidt, C. A.

2012-12-01

The use of N-based fertilizer will need to increase to meet future demands, yet existing applications have been implicated as the main source of coastal eutrophication and hypoxic zones. Producing sufficient crops to feed a growing planet will require efficient production in combination with sustainable treatment solutions. The long-term success of denitrification bioreactors to effectively remove nitrate (NO¬3), indicates this technology is a feasible treatment option. Assessing and quantifying the media properties that affect NO¬3 removal rate and microbial activity can improve predictions on bioreactor performance. It was hypothesized that denitrification rates and microbial biomass would be correlated with total C, NO¬3 concentration, metrics of organic matter quality, media surface area and laboratory measures of potential denitrification rate. NO¬3 removal rates and microbial biomass were evaluated in mesocosms filled with different wood treatments and the unique influence of these predictor variables was determined using a multiple linear regression analysis. NO3 reduction rates were independent of NO¬3 concentration indicating zero order reaction kinetics. Temperature was strongly correlated with denitrification rate (r2=0.87; Q10=4.7), indicating the variability of bioreactor performance in differing climates. Fiber quality, and media surface area were strong (R>0.50), unique predictors of rates and microbial biomass, although C:N ratio and potential denitrification rate did not predict actual denitrification rate or microbial biomass. Utilizing a stepwise multiple linear regression, indicates that the denitrification rate can be effectively (r2=0.56;p<0.0001) predicted if the groundwater temperature, neutral detergent fiber and surface area alone are quantified. These results will assist with the widespread implementation of denitrification bioreactors to achieve significant N load reductions in large watersheds. The nitrate reduction rate as a function of groundwater temperature for all treatments. Correlations between nitrate reduction rate and properties of carbon media;

Centralizing content and distributing labor: a community model for curating the very long tail of microbial genomes.

PubMed

Putman, Tim E; Burgstaller-Muehlbacher, Sebastian; Waagmeester, Andra; Wu, Chunlei; Su, Andrew I; Good, Benjamin M

2016-01-01

The last 20 years of advancement in sequencing technologies have led to sequencing thousands of microbial genomes, creating mountains of genetic data. While efficiency in generating the data improves almost daily, applying meaningful relationships between taxonomic and genetic entities on this scale requires a structured and integrative approach. Currently, knowledge is distributed across a fragmented landscape of resources from government-funded institutions such as National Center for Biotechnology Information (NCBI) and UniProt to topic-focused databases like the ODB3 database of prokaryotic operons, to the supplemental table of a primary publication. A major drawback to large scale, expert-curated databases is the expense of maintaining and extending them over time. No entity apart from a major institution with stable long-term funding can consider this, and their scope is limited considering the magnitude of microbial data being generated daily. Wikidata is an openly editable, semantic web compatible framework for knowledge representation. It is a project of the Wikimedia Foundation and offers knowledge integration capabilities ideally suited to the challenge of representing the exploding body of information about microbial genomics. We are developing a microbial specific data model, based on Wikidata's semantic web compatibility, which represents bacterial species, strains and the gene and gene products that define them. Currently, we have loaded 43,694 gene and 37,966 protein items for 21 species of bacteria, including the human pathogenic bacteriaChlamydia trachomatis.Using this pathogen as an example, we explore complex interactions between the pathogen, its host, associated genes, other microbes, disease and drugs using the Wikidata SPARQL endpoint. In our next phase of development, we will add another 99 bacterial genomes and their gene and gene products, totaling ∼900,000 additional entities. This aggregation of knowledge will be a platform for community-driven collaboration, allowing the networking of microbial genetic data through the sharing of knowledge by both the data and domain expert. © The Author(s) 2016. Published by Oxford University Press.

Effects of Variety and Postharvest Handling Practices on Microbial Population at Different Stages of the Value Chain of Fresh Tomato (Solanum lycopersicum) in Western Terai of Nepal

PubMed Central

Marasini, Madan; Rawal, Ranjana; Gautam, Durga M.; Acedo, Antonio L.

2017-01-01

Background. Fresh vegetables such as tomato should have low microbial population for safe consumption and long storage life. The aerobic bacterial count (ABC) and coliform bacterial count (CBC), yeast, and mold population are the most widely used microbial indicators in fresh vegetables which should be lower than 4 log CFU g−1 for safe consumption. The stages of the supply chain, postharvest handling methods, and crop varieties had significant effects on microbial population. ABC, CBC, yeast, and mold population were significantly highest (P < 0.05) at retail market (5.59, 4.38, 2.60, and 3.14 log CFU g−1, resp.), followed by wholesale market (4.72, 4.71, 2.43, and 2.44 log CFU g−1, resp.), and were least at farm gate (3.89, 3.63, 2.38, and 2.03 log CFU g−1, resp.). Improved postharvest practices (washing in clean water and grading and packaging in clean plastic crate) helped to reduce ABC, CBC, and mold population by 2.51, 32.70, and 29.86 percentage as compared to the conventional method (no washing and no grading and packaging in mud plastered bamboo baskets). Among varieties, Pusa ruby had the lowest microbial load of 2.58, 4.53, 0.96, and 1.77 log CFU g−1 for ABC, CBC, yeast, and mold count, respectively. Significantly negative correlation (P < 0.05) was observed between fruit pH & ABC and pH & mold count. Although the microbial quality of fresh tomato is safe in the local market of western Terai of Nepal both in conventional and in improved practices however still it is essential to follow improved postharvest handling practices in production and marketing of newly introduced tomato cultivars (high-pH cultivars) for ensuring the safe availability of fresh tomato in the market. PMID:29124068

New insight into microbial diversity and functions in traditional Vietnamese alcoholic fermentation.

PubMed

Thanh, Vu Nguyen; Thuy, Nguyen Thanh; Chi, Nguyen Thuy; Hien, Dinh Duc; Ha, Bui Thi Viet; Luong, Dao Thi; Ngoc, Pham Duc; Ty, Pham Van

2016-09-02

The roles of microorganisms in traditional alcoholic fermentation are often assumed based on abundance in the starter and activity in pure culture. There is a serious lack of hard evidence on the behavior and activity of individual microbial species during the actual fermentation process. In this study, microbial succession and metabolite changes during 7days of traditional Vietnamese alcoholic fermentation were monitored. Special attention was devoted to starch degradation. In total, 22 microbial species, including 6 species of filamentous fungi (Rhizopus microsporus, Rhizopus arrhizus, Mucor indicus, Mucor circinelloides, Cunninghamella elegans, Aspergillus niger), 1 yeast-like fungus (Saccharomycopsis fibuligera), 7 yeasts (Saccharomyces cerevisiae, Clavispora lusitaniae, Wickerhamomyces anomalus, Lindnera fabianii, Pichia kudriavzevii, Candida rugosa, Candida tropicalis), and 8 bacteria (Stenotrophomonas maltophilia, Lactobacillus brevis, Lactobacillus helveticus, Acinetobacter baumannii, Staphylococcus hominis, Bacillus megaterium, Enterobacter asburiae, Pediococcus pentosaceus) were identified. Despite the presence of a complex microbiota in the starter, the fermentation process is consistent and involves a limited number of functional species. Rapid change in microbial composition of fermentation mash was observed and it was correlated with ethanol content. Microbial biomass reached maximum during first 2days of solid state fermentation. Acidification of the medium took place in day 1, starch degradation in days 2, 3, 4, and alcohol accumulation from day 3. Although Sm. fibuligera dominated by cell count amongst potential starch degraders, zymography indicated that it did not produce amylase in the fermentation mash. In mixed culture with Rhizopus, amylase production by Sm. fibuligera is regulated by the moisture content of the substrate. Rhizopus was identified as the main starch degrader and S. cerevisiae as the main ethanol producer. Bacterial load was high but unstable in species composition and dominated by acid producers. M. indicus, Sm. fibuligera, W. anomalus and bacteria were regarded as satellite microorganisms. Their possible influence on organoleptic quality of fermentation product was discussed. Copyright © 2016 Elsevier B.V. All rights reserved.

Expansion of Microbial Monitoring Capabilities on the International Space Station (ISS)

NASA Technical Reports Server (NTRS)

Khodadad, Christina L.; Oubre, Cherie; Castro, Victoria; Flint, Stephanie; Melendez, Orlando; Ott, C. Mark; Roman, Monsi

2017-01-01

Microbial monitoring is one of the tools that the National Aeronautics and Space Administration (NASA) uses on the International Space Station (ISS) to help maintain crew health and safety. In combination with regular housekeeping and disinfection when needed, microbial monitoring provides important information to the crew about the quality of the environment. Rotation of astronauts, equipment, and cargo on the ISS can affect the microbial load in the air, surfaces, and water. The current ISS microbial monitoring methods are focused on culture-based enumeration during flight and require a significant amount of crew time as well as long incubation periods of up to 5 days there by proliferating potential pathogens. In addition, the samples require return to Earth for complete identification of the microorganisms cultivated. Although the current approach assess the quality of the ISS environment, molecular technology offers faster turn-around of information particularly beneficial in an off-nominal situation. In 2011, subject matter experts from industry and academia recommended implementation of molecular-based technologies such as quantitative real-time polymerase chain reaction (qPCR) for evaluation to replace current, culture-based technologies. The RAZOR EX (BioFire Defense, Inc, Salt Lake City, UT) a ruggedized, compact, COTS (commercial off the shelf) qPCR instrument was tested, evaluated and selected in the 2 X 2015 JSC rapid flight hardware demonstration initiative as part of the Water Monitoring Suite. RAZOR EX was launched to ISS on SpaceX-9 in July 2016 to evaluate the precision and accuracy of the hardware by testing various concentrations of DNA in microgravity compared to ground controls. Flight testing was completed between September 2016 and March 2017. Data presented will detail the hardware performance of flight testing results compared to ground controls. Future goals include additional operational ground-based testing and assay development to determine if this technology can meet spaceflight microbial monitoring requirements.

Microbial abundance on the eggs of a passerine bird and related fitness consequences between urban and rural habitats.

PubMed

Lee, Sang-Im; Lee, Hyunna; Jablonski, Piotr G; Choe, Jae Chun; Husby, Magne

2017-01-01

Urban environments present novel and challenging habitats to wildlife. In addition to well-known difference in abiotic factors between rural and urban environments, the biotic environment, including microbial fauna, may also differ significantly. In this study, we aimed to compare the change in microbial abundance on eggshells during incubation between urban and rural populations of a passerine bird, the Eurasian Magpie (Pica pica), and examine the consequences of any differences in microbial abundances in terms of hatching success and nestling survival. Using real-time PCR, we quantified the abundances of total bacteria, Escherichia coli/Shigella spp., surfactin-producing Bacillus spp. and Candida albicans on the eggshells of magpies. We found that urban magpie eggs harboured greater abundances of E. coli/Shigella spp. and C. albicans before incubation than rural magpie eggs. During incubation, there was an increase in the total bacterial load, but a decrease in C. albicans on urban eggs relative to rural eggs. Rural eggs showed a greater increase in E. coli/Shigella spp. relative to their urban counterpart. Hatching success of the brood was generally lower in urban than rural population. Nestling survival was differentially related with the eggshell microbial abundance between urban and rural populations, which was speculated to be the result of the difference in the strength of the interaction among the microbes. This is the first demonstration that avian clutches in urban and rural populations differ in eggshell microbial abundance, which can be further related to the difference in hatching success and nestling survival in these two types of environments. We suggest that future studies on the eggshell microbes should investigate the interaction among the microbes, because the incubation and/or environmental factors such as urbanization or climate condition can influence the dynamic interactions among the microbes on the eggshells which can further determine the breeding success of the parents.

Broiler Litter × Industrial By-Products Reduce Nutrients and Microbial Losses in Surface Runoff When Applied to Forages.

PubMed

Adeli, Ardeshir; Read, John J; Brooks, John P; Miles, Dana; Feng, Gary; Jenkins, Johnie N

2017-03-01

The inability to incorporate broiler litter (BL) into permanent hayfields and pastures leads to nutrient accumulation near the soil surface and increases the potential transport of nutrients in runoff. This study was conducted on Marietta silt loam soil to determine the effect of flue gas desulfurization (FGD) gypsum and lignite on P, N, C, and microbial concentrations in runoff. Treatments were (i) control (unfertilized) and (ii) BL at 13.4 Mg ha alone or (iii) treated with either FGD gypsum or lignite applied at 20% (w/w) (2.68 Mg ha). Rainfall simulators were used to produce a 5.6 cm h storm event sufficient in duration to cause 15 min of continuous runoff. Repeated rains were applied at 3-d intervals to determine how long FGD gypsum and lignite are effective in reducing loss of litter-derived N, P, and C from soil. Application of BL increased N, P, and C concentrations in runoff as compared to the control. Addition of FGD gypsum reduced ( < 0.05) water-soluble P and dissolved organic C concentrations in runoff by 39 and 16%, respectively, as compared to BL alone. Lignite reduced runoff total N and NH-N concentrations by 38 and 70%, respectively, as compared to BL alone. Addition of FGD gypsum or lignite failed to significantly reduce microbial loads in runoff, although both treatments reduced microbial concentration by >20%. Thus, BL treated with FGD and lignite can be considered as cost-effective management practices in the mitigation of P, N, and C and possibly microbial concentration in runoff. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

The Impact of Human Activities on Microbial Quality of Rivers in the Vhembe District, South Africa.

PubMed

Traoré, Afsatou N; Mulaudzi, Khodani; Chari, Gamuchirai J E; Foord, Stefan H; Mudau, Lutendo S; Barnard, Tobias G; Potgieter, Natasha

2016-08-12

Water quality testing is dictated by microbial agents found at the time of sampling in reference to their acceptable risk levels. Human activities might contaminate valuable water resources and add to the microbial load present in water bodies. Therefore, the effects of human activities on the microbial quality of rivers collected from twelve catchments in the Vhembe District in South Africa were investigated, with samples analyzed for total coliform (TC) and Eschericha coli (E. coli) contents. Physical parameters and various human activities were recorded for each sampling site. The Quanti-Tray(®) method was adopted for the assessment of TC and E. coli contents in the rivers over a two-year period. A multiplex polymerase chain (PCR) method was used to characterize the strains of E. coli found. The microbial quality of the rivers was poor with both TC and E. coli contents found to be over acceptable limits set by the South African Department of Water and Sanitation (DWS). No significant difference (p > 0.05) was detected between TC and E. coli risks in dry and wet seasons. All six pathogenic E. coli strains were identified and Enteroaggregative E. coli (EAEC), atypical Enteropathogenic E. coli (a-EPEC) and Enterotoxigenic E. coli (ETEC) were the most prevalent E. coli strains detected (respectively, 87%, 86% and 83%). The study indicated that contamination in the majority of sampling sites, due to human activities such as car wash, animal grazing and farming, poses health risks to communities using the rivers for various domestic chores. It is therefore recommended that more education by the respective departments is done to avert pollution of rivers and prevent health risks to the communities in the Vhembe District.

The Impact of Human Activities on Microbial Quality of Rivers in the Vhembe District, South Africa

PubMed Central

Traoré, Afsatou N.; Mulaudzi, Khodani; Chari, Gamuchirai J.E.; Foord, Stefan H.; Mudau, Lutendo S.; Barnard, Tobias G.; Potgieter, Natasha

2016-01-01

Background: Water quality testing is dictated by microbial agents found at the time of sampling in reference to their acceptable risk levels. Human activities might contaminate valuable water resources and add to the microbial load present in water bodies. Therefore, the effects of human activities on the microbial quality of rivers collected from twelve catchments in the Vhembe District in South Africa were investigated, with samples analyzed for total coliform (TC) and Eschericha coli (E. coli) contents. Methods: Physical parameters and various human activities were recorded for each sampling site. The Quanti-Tray® method was adopted for the assessment of TC and E. coli contents in the rivers over a two-year period. A multiplex polymerase chain (PCR) method was used to characterize the strains of E. coli found. Results: The microbial quality of the rivers was poor with both TC and E. coli contents found to be over acceptable limits set by the South African Department of Water and Sanitation (DWS). No significant difference (p > 0.05) was detected between TC and E. coli risks in dry and wet seasons. All six pathogenic E. coli strains were identified and Enteroaggregative E. coli (EAEC), atypical Enteropathogenic E. coli (a-EPEC) and Enterotoxigenic E. coli (ETEC) were the most prevalent E. coli strains detected (respectively, 87%, 86% and 83%). Conclusions: The study indicated that contamination in the majority of sampling sites, due to human activities such as car wash, animal grazing and farming, poses health risks to communities using the rivers for various domestic chores. It is therefore recommended that more education by the respective departments is done to avert pollution of rivers and prevent health risks to the communities in the Vhembe District. PMID:27529265

Short-term microbial dynamics in a drinking water plant treating groundwater with occasional high microbial loads.

PubMed

Besmer, Michael D; Hammes, Frederik

2016-12-15

Short-term fluctuations in bacterial concentrations in drinking water systems, occurring on time scales of hours-to-weeks, are essentially unexplored due to a lack of microbial monitoring tools that allow high frequency measurements. Here, we applied fully automated online flow cytometry to measure the total cell concentrations (TCC) in both raw water (karstic groundwater) and treated water (flocculation - ultrafiltration (UF) - ozonation - granular active carbon (GAC) filtration) during a period of 70 days at high temporal resolution (n > 4000 for both water types). We detected and characterized in considerable detail aperiodic fluctuations in the raw water following regional precipitation, with TCC increasing up to 50-fold from a dry weather baseline of approximately 120 cells μl -1 to an event peak of > 5000 cells μl -1 . Moreover, we observed the buffering of the treatment plant against these fluctuations, but in addition we recorded a completely unexpected periodic fluctuation of TCC in the treated water after GAC filtration. We concluded that the latter was the result of fluctuating water abstraction from the treatment plant reservoir by two connected water utilities, which resulted in variations in water throughput in the plant. This in turn influenced bacterial detachment and dilution in the GAC filter. This study provides strong evidence of multiple different microbial dynamics occurring in a drinking water treatment system. Given numerous possible sources of natural and operational fluctuations in raw water and drinking water treatment plants, such microbial fluctuations should be expected in many systems. The high-frequency monitoring approach presented herein can improve the understanding and eventual mitigation of such fluctuations. Copyright © 2016 Elsevier Ltd. All rights reserved.

Development of a Chlorine Dosing Strategy for Fresh Produce Washing Process to Maintain Microbial Food Safety and Minimize Residual Chlorine.

PubMed

Chen, Xi; Hung, Yen-Con

2018-06-01

The residual free chlorine level in fresh produce wash solution is closely correlated to the chemical and microbial safety of produce. Excess amount of free chlorine can quickly react with organic matters to form hazardous disinfection by-products (DBPs) above EPA-permitted levels, whereas deficiency of residual chlorine in produce wash solution may result in incompletely removing pathogens on produce. The purpose of this study was to develop a chlorine dosing strategy to optimize the chlorine dosage during produce washing process without impacting the microbial safety of fresh produce. Prediction equations were developed to estimate free chlorine needed to reach targeted residual chlorine at various sanitizer pH and organic loads, and then validated using fresh-cut iceberg lettuce and whole strawberries in an automated produce washer. Validation results showed that equations successfully predicted the initial chlorine concentration needed to achieve residual chlorine at 10, 30, 60, and 90 mg/L for both lettuce and strawberry washing processes, with the root mean squared error at 4.45 mg/L. The Escherichia coli O157:H7 reductions only slightly increased on iceberg lettuce and strawberries with residual chlorine increasing from 10 to 90 mg/L, indicating that lowering residual chlorine to 10 mg/L would not compromise the antimicrobial efficacy of chlorine-based sanitizer. Based on the prediction equations and E. coli O157:H7 reduction results, a chlorine dosing strategy was developed to help the produce industry to maintain microbial inactivation efficacy without adding excess amount of free chlorine. The chlorine dosing strategy can be used for fresh produce washing process to enhance the microbial food safety and minimize the DBPs formation potential. © 2018 Institute of Food Technologists®.

Metagenomic analysis of soil and freshwater from zoo agricultural area with organic fertilization

PubMed Central

Meneghine, Aylan K.; Nielsen, Shaun; Thomas, Torsten; Carareto Alves, Lucia Maria

2017-01-01

Microbial communities drive biogeochemical cycles in agricultural areas by decomposing organic materials and converting essential nutrients. Organic amendments improve soil quality by increasing the load of essential nutrients and enhancing the productivity. Additionally, fresh water used for irrigation can affect soil quality of agricultural soils, mainly due to the presence of microbial contaminants and pathogens. In this study, we investigated how microbial communities in irrigation water might contribute to the microbial diversity and function of soil. Whole-metagenomic sequencing approaches were used to investigate the taxonomic and the functional profiles of microbial communities present in fresh water used for irrigation, and in soil from a vegetable crop, which received fertilization with organic compost made from animal carcasses. The taxonomic analysis revealed that the most abundant genera were Polynucleobacter (~8% relative abundance) and Bacillus (~10%) in fresh water and soil from the vegetable crop, respectively. Low abundance (0.38%) of cyanobacterial groups were identified. Based on functional gene prediction, denitrification appears to be an important process in the soil community analysed here. Conversely, genes for nitrogen fixation were abundant in freshwater, indicating that the N-fixation plays a crucial role in this particular ecosystem. Moreover, pathogenicity islands, antibiotic resistance and potential virulence related genes were identified in both samples, but no toxigenic genes were detected. This study provides a better understanding of the community structure of an area under strong agricultural activity with regular irrigation and fertilization with an organic compost made from animal carcasses. Additionally, the use of a metagenomic approach to investigate fresh water quality proved to be a relevant method to evaluate its use in an agricultural ecosystem. PMID:29267397

Elucidating microbial community adaptation to anaerobic co-digestion of fats, oils, and grease and food waste.

PubMed

Amha, Yamrot M; Sinha, Pooja; Lagman, Jewls; Gregori, Matt; Smith, Adam L

2017-10-15

Despite growing interest in co-digestion and demonstrated process improvements (e.g., enhanced stability and biogas production), few studies have evaluated how co-digestion impacts the anaerobic digestion (AD) microbiome. Three sequential bench-scale respirometry experiments were conducted at thermophilic temperature (50 °C) with various combinations of primary sludge (PS); thickened waste activated sludge (TWAS); fats, oils, and grease (FOG); and food waste (FW). Two additional runs were then performed to evaluate microbial inhibition at higher organic fractions of FOG (30-60% volatile solids loading (VSL; v/v)). Co-digestion of PS, TWAS, FOG, and FW resulted in a 26% increase in methane production relative to digestion of PS and TWAS. A substantial lag time was observed in biogas production for vessels with FOG addition that decreased by more than half in later runs, likely due to adaptation of the microbial community. 30% FOG with 10% FW showed the highest increase in methane production, increasing 53% compared to digestion of PS and TWAS. FOG addition above 50% VSL was found to be inhibitory with and without FW addition and resulted in volatile fatty acid (VFA) accumulation. Methane production was linked with high relative activity and abundance of syntrophic fatty-acid oxidizers alongside hydrogenotrophic methanogens, signaling the importance of interspecies interactions in AD. Specifically, relative activity of Syntrophomonas was significantly correlated with methane production. Further, methane production increased over subsequent runs along with methyl coenzyme M reductase (mcrA) gene expression, a functional gene in methanogens, suggesting temporal adaptation of the microbial community to co-digestion substrate mixtures. The study demonstrated the benefits of co-digestion in terms of performance enhancement and enrichment of key active microbial populations. Copyright © 2017 Elsevier Ltd. All rights reserved.

Impact of heavy metal on activity of some microbial enzymes in the riverbed sediments: Ecotoxicological implications in the Ganga River (India).

PubMed

Jaiswal, Deepa; Pandey, Jitendra

2018-04-15

We studied the extracellular enzyme activity (EEA) in the riverbed sediment along a 518km gradient of the Ganga River receiving carbon and nutrient load from varied human sources. Also, we tested, together with substrate-driven stimulation, if the heavy metal accumulated in the sediment inhibits enzyme activities. Because pristine values are not available, we considered Dev Prayag, a least polluted site located 624km upstream to main study stretch, as a reference site. There were distinct increases in enzyme activities in the sediment along the study gradient from Dev Prayag, however, between-site differences were in concordance with sediment carbon(C), nitrogen (N) and phosphorus (P). Fluorescein diacetate hydrolysis (FDAase), β-glucosidase (Glu) and protease activities showed positive correlation with C, N and P while alkaline phosphatase was found negatively correlated with P. Enzyme activities were found negatively correlated with heavy metal, although ecological risk index (E R i ) varied with site and metal species. Dynamic fit curves showed significant positive correlation between heavy metal and microbial metabolic quotient (qCO 2 ) indicating a decrease in microbial activity in response to increasing heavy metal concentrations. This study forms the first report linking microbial enzyme activities to regional scale sediment heavy metal accumulation in the Ganga River, suggests that the microbial enzyme activities in the riverbed sediment were well associated with the proportion of C, N and P and appeared to be a sensitive indicator of C, N and P accumulation in the river. Heavy metal accumulated in the sediment inhibits enzyme activities, although C rich sediment showed relatively low toxicity due probably to reduced bioavailability of the metal. The study has relevance from ecotoxicological as well as from biomonitoring perspectives. Copyright © 2017 Elsevier Inc. All rights reserved.

A distinct bacterial dysbiosis associated skin inflammation in ovine footrot

NASA Astrophysics Data System (ADS)

Maboni, Grazieli; Blanchard, Adam; Frosth, Sara; Stewart, Ceri; Emes, Richard; Tötemeyer, Sabine

2017-03-01

Ovine footrot is a highly prevalent bacterial disease caused by Dichelobacter nodosus and characterised by the separation of the hoof horn from the underlying skin. The role of innate immune molecules and other bacterial communities in the development of footrot lesions remains unclear. This study shows a significant association between the high expression of IL1β and high D. nodosus load in footrot samples. Investigation of the microbial population identified distinct bacterial populations in the different disease stages and also depending on the level of inflammation. Treponema (34%), Mycoplasma (29%) and Porphyromonas (15%) were the most abundant genera associated with high levels of inflammation in footrot. In contrast, Acinetobacter (25%), Corynebacteria (17%) and Flavobacterium (17%) were the most abundant genera associated with high levels of inflammation in healthy feet. This demonstrates for the first time there is a distinct microbial community associated with footrot and high cytokine expression.

Effect of combination processing on the microbial, chemical and sensory quality of ready-to-eat (RTE) vegetable pulav

NASA Astrophysics Data System (ADS)

Kumar, R.; George, Johnsy; Rajamanickam, R.; Nataraju, S.; Sabhapathy, S. N.; Bawa, A. S.

2011-12-01

Effect of irradiation in combination with retort processing on the shelf life and safety aspects of an ethnic Indian food product like vegetable pulav was investigated. Gamma irradiation of RTE vegetable pulav was carried out at different dosage rates with 60Co followed by retort processing. The combination processed samples were analysed for microbiological, chemical and sensory characteristics. Microbiological analysis indicated that irradiation in combination with retort processing has significantly reduced the microbial loads whereas the chemical and sensory analysis proved that this combination processing is effective in retaining the properties even after storage for one year at ambient conditions. The results also indicated that a minimum irradiation dosage at 4.0 kGy along with retort processing at an F0 value of 2.0 is needed to achieve the desired shelf life with improved organoleptic qualities.

Enhancing biomethanogenic treatment of fresh incineration leachate using single chambered microbial electrolysis cells.

PubMed

Gao, Yan; Sun, Dezhi; Dang, Yan; Lei, Yuqing; Ji, Jiayang; Lv, Tingwei; Bian, Rui; Xiao, Zhihui; Yan, Liangming; Holmes, Dawn E

2017-05-01

Methanogenic treatment of municipal solid waste (MSW) incineration leachate can be hindered by high concentrations of refractory organic matter and humification of compounds in the leachate. In an attempt to overcome some of these impediments, microbial electrolysis cells (MECs) were incorporated into anaerobic digesters (ADMECs). COD removal efficiencies and methane production were 8.7% and 44.3% higher in ADMECs than in controls, and ADMEC reactors recovered more readily from souring caused by high organic loading rates. The degradation rate of large macromolecules was substantially higher (96% vs 81%) in ADMEC than control effluent, suggesting that MECs stimulated degradation of refractory organic matter and reduced humification. Exoelectrogenic bacteria and microorganisms known to form syntrophic partnerships were enriched in ADMECs. These results show that ADMECs were more effective at treatment of MSW incineration leachate, and should be taken into consideration when designing future treatment facilities. Copyright © 2017 Elsevier Ltd. All rights reserved.

New insights in the pathogenesis of atopic disease.

PubMed

Ionescu, John G

2009-01-01

A causal link between the increasing environmental pollution and the fast spreading of allergic diseases is currently discussed. The exogenic and endogenic noxious agents contributing to the total environmental load are primarily acting through immunotoxic, sensitizing and neurotoxic mechanisms in animal experiments and in humans. Beside classic allergic-triggering factors (allergen potency, intermittent exposure to different allergen concentrations, presence of microbial bodies and sensitizing phenols), the adjuvant role of environmental pollutants gains increasing importance in allergy induction. Our therapy experience with more than 18.000 atopic eczema patients shows that beside allergic reactions pseudoallergic mechanisms through toxic environmental agents (formaldehyde, industrial and traffic smog, wood preservatives, microbial toxins, additive-rich food, nicotine, alcohol, pesticides, solvents, amalgam-heavy metals) are increasingly incriminated as causal factors for the complex symptomatology. The avoidance and elimination of such triggering factors before and during pregnancy and in early childhood may result in a significant decrease of the incidence of atopic diseases.

Improvement of Biogas Production by Bioaugmentation

PubMed Central

Kovács, K. L.; Ács, N.; Kovács, E.; Wirth, R.; Rákhely, G.; Strang, Orsolya; Herbel, Zsófia; Bagi, Z.

2013-01-01

Biogas production technologies commonly involve the use of natural anaerobic consortia of microbes. The objective of this study was to elucidate the importance of hydrogen in this complex microbial food chain. Novel laboratory biogas reactor prototypes were designed and constructed. The fates of pure hydrogen-producing cultures of Caldicellulosiruptor saccharolyticus and Enterobacter cloacae were followed in time in thermophilic and mesophilic natural biogas-producing communities, respectively. Molecular biological techniques were applied to study the altered ecosystems. A systematic study in 5-litre CSTR digesters revealed that a key fermentation parameter in the maintenance of an altered population balance is the loading rate of total organic solids. Intensification of the biogas production was observed and the results corroborate that the enhanced biogas productivity is associated with the increased abundance of the hydrogen producers. Fermentation parameters did not indicate signs of failure in the biogas production process. Rational construction of more efficient and sustainable biogas-producing microbial consortia is proposed. PMID:23484123

Long-term effects of the transient COD concentration on the performance of microbial fuel cells.

PubMed

Mateo, S; Gonzalez Del Campo, A; Lobato, J; Rodrigo, M; Cañizares, P; Fernandez-Morales, F J

2016-07-08

In this work, the long-term effects of transient chemical oxygen demands (COD) concentrations over the performance of a microbial fuel cell were studied. From the obtained results, it was observed that the repetitive change in the COD loading rate during 12 h conditioned the behavior of the system during periods of up to 7 days. The main modifications were the enhancement of the COD consumption rate and the exerted current. These enhancements yielded increasing Coulombic efficiencies (CEs) when working with COD concentrations of 300 mg/L, but constant CEs when working with COD concentrations from 900 to 1800 mg/L. This effect could be explained by the higher affinity for the substrate of Geobacter than that of the nonelectrogenic organisms such as Clostridia. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:883-890, 2016. © 2016 American Institute of Chemical Engineers.

Influence of hyaluronic acid on bacterial and fungal species, including clinically relevant opportunistic pathogens.

PubMed

Ardizzoni, Andrea; Neglia, Rachele G; Baschieri, Maria C; Cermelli, Claudio; Caratozzolo, Manuela; Righi, Elena; Palmieri, Beniamino; Blasi, Elisabetta

2011-10-01

Hyaluronic acid (HA) has several clinical applications (aesthetic surgery, dermatology, orthopaedics and ophtalmology). Following recent evidence, suggesting antimicrobial and antiviral properties for HA, we investigated its effects on 15 ATCC strains, representative of clinically relevant bacterial and fungal species. The in vitro system employed allowed to assess optical density of broth cultures as a measure of microbial load in a time-dependent manner. The results showed that different microbial species and, sometimes, different strains belonging to the same species, are differently affected by HA. In particular, staphylococci, enterococci, Streptococcus mutans, two Escherichia coli strains, Pseudomonas aeruginosa, Candida glabrata and C. parapsilosis displayed a HA dose-dependent growth inhibition; no HA effects were detected in E. coli ATCC 13768 and C. albicans; S. sanguinis was favoured by the highest HA dose. Therefore, the influence of HA on bacteria and fungi warrants further studies aimed at better establishing its relevance in clinical applications.

Simulation and resolution of voltage reversal in microbial fuel cell stack.

PubMed

Sugnaux, Marc; Savy, Cyrille; Cachelin, Christian Pierre; Hugenin, Gérald; Fischer, Fabian

2017-08-01

To understand the biotic and non-biotic contributions of voltage reversals in microbial fuel cell stacks (MFC) they were simulated with an electronic MFC-Stack mimic. The simulation was then compared with results from a real 3L triple MFC-Stack with shared anolyte. It showed that voltage reversals originate from the variability of biofilms, but also the external load plays a role. When similar biofilm properties were created on all anodes the likelihood of voltage reversals was largely reduced. Homogenous biofilms on all anodes were created by electrical circuit alternation and electrostimulation. Conversely, anolyte recirculation, or increased nutriment supply, postponed reversals and unfavourable voltage asymmetries on anodes persisted. In conclusion, voltage reversals are often a negative event but occur also in close to best MFC-Stack performance. They were manageable and this with a simplified MFC architecture in which multiple anodes share the same anolyte. Copyright © 2017 Elsevier Ltd. All rights reserved.

New Insights in the Pathogenesis of Atopic Disease

PubMed Central

Ionescu, GJ

2009-01-01

A causal link between the increasing environmental pollution and the fast spreading of allergic diseases is currently discussed. The exogenic and endogenic noxious agents contributing to the total environmental load are primarily acting through immunotoxic, sensitizing and neurotoxic mechanisms in animal experiments and in humans. Beside classic allergic–triggering factors (allergen potency, intermittent exposure to different allergen concentrations, presence of microbial bodies and sensitizing phenols), the adjuvant role of environmental pollutants gains increasing importance in allergy induction. Our therapy experience with more than 18.000 atopic eczema patients shows that beside allergic reactions pseudoallergic mechanisms through toxic environmental agents (formaldehyde, industrial and traffic smog, wood preservatives, microbial toxins, additive–rich food, nicotine, alcohol, pesticides, solvents, amalgam–heavy metals) are increasingly incriminated as causal factors for the complex symptomatology. The avoidance and elimination of such triggering factors before and during pregnancy and in early childhood may result in a significant decrease of the incidence of atopic diseases.

New Insights in the Pathogenesis of Atopic Disease

PubMed Central

John G., Ionescu

2009-01-01

A causal link between the increasing environmental pollution and the fast spreading of allergic diseases is currently discussed. The exogenic and endogenic noxious agents contributing to the total environmental load are primarily acting through immunotoxic, sensitizing and neurotoxic mechanisms in animal experiments and in humans. Beside classic allergic-triggering factors (allergen potency, intermittent exposure to different allergen concentrations, presence of microbial bodies and sensitizing phenols), the adjuvant role of environmental pollutants gains increasing importance in allergy induction. Our therapy experience with more than 18.000 atopic eczema patients shows that beside allergic reactions pseudoallergic mechanisms through toxic environmental agents (formaldehyde, industrial and traffic smog, wood preservatives, microbial toxins, additive-rich food, nicotine, alcohol, pesticides, solvents, amalgam-heavy metals) are increasingly incriminated as causal factors for the complex symptomatology. The avoidance and elimination of such triggering factors before and during pregnancy and in early childhood may result in a significant decrease of the incidence of atopic diseases. PMID:20108533

Delivery of drugs bound to erythrocytes: new avenues for an old intravascular carrier

PubMed Central

Villa, Carlos H; Pan, Daniel C; Zaitsev, Sergei; Cines, Douglas B; Siegel, Donald L; Muzykantov, Vladimir R

2015-01-01

For several decades, researchers have used erythrocytes for drug delivery of a wide variety of therapeutics in order to improve their pharmacokinetics, biodistribution, controlled release and pharmacodynamics. Approaches include encapsulation of drugs within erythrocytes, as well as coupling of drugs onto the red cell surface. This review focuses on the latter approach, and examines the delivery of red blood cell (RBC)-surface-bound anti-inflammatory, anti-thrombotic and anti-microbial agents, as well as RBC carriage of nanoparticles. Herein, we discuss the progress that has been made in surface loading approaches, and address in depth the issues relevant to surface loading of RBC, including intrinsic features of erythrocyte membranes, immune considerations, potential surface targets and techniques for the production of affinity ligands. PMID:26228773

[Effect of excess ethanol on the growth of yeasts of the genus Candida during continuous cultivation].

PubMed

Shkidchenko, A N; Shul'ga, A V; Gurina, L V

1988-01-01

The effect of flow rates and a specific ethanol load on the growth of Candida utilis and Candida krusei was studied in the process of one-step and three-step cultivation. The productive capacity of fermenters and the economic coefficient of yeast biomass production were shown to depend on the ability of microbial populations to assimilate a certain quantity of a carbon substrate per unit time. When a specific ethanol load exceeds the optimal one, the respiratory activity of a population and the economic coefficient of growth fall down whereas the accumulation of metabolites in the cultural broth increases. The steady state of biomass can be maintained in the process of continuous cultivation by inhibiting the yeast growth with an excess of ethanol.

Study of the Microbial Diversity of a Newly Discovered East Antarctic Freshwater Lake, L27C, and of a Perennially Ice-Covered Lake Untersee

NASA Technical Reports Server (NTRS)

Huang, Jonathan P.; Hoover, Richard B.; Andersen, Dale; Bej, Asim K.

2010-01-01

The microbial communities that reside within freshwater lakes of Schirmacher and Untersee Oases in East Antarctica must cope with extreme conditions that may include cold temperature, annual freeze-thaw cycles, exposure to UV radiation, especially during the austral summer months, low light beneath thick ice-cover, followed by seasonal darkness. The objective of this study was to assess the microbial biodiversity and distribution from samples taken from two freshwater lakes (L27C and Lake Untersee) that were collected during the Tawani 2008 International Antarctic Expedition that conducted research in this region of Antarctica. L27C is a small, previously unreported lake residing 2 km WNW of Maitri Station at Schirmacher Oasis. Biodiversity and distribution of microorganisms within the lake were studied using both culture-independent and culture-dependent methodologies based upon the analysis of eubacterial 16S rRNA gene sequences. Lake Untersee, a perennially ice-covered, ultra-oligotrophic, lake in the Otto-von-Gruber-Gebirge (Gruber Mountains) of central Dronning Maud Land was also sampled and the microbial diversity was analyzed by eubacterial 16S rRNA gene sequences derived from pure cultures. Direct culturing of water samples from each lake on separate R2A growth medium exhibited a variety of microorganisms including: Janthinobacterium, Hymenobacter, Sphingamonas, Subtercola, Deinococcus, Arthrobacter, Flavobacterium, Polaromonas, Rhodoferax and Duganella. The evaluation of samples from L27C through culture-independent methodology identified a rich microbial diversity consisting of six different phyla of bacteria. The culture-independent analysis also displayed the majority of bacteria (56%) belonged to the Class gamma-proteobacteria within the phylum Proteobacteria. Within the Class gamma-proteobacteria, Acinetobacter dominated (48%) the total microbial load. Overall, L27C exhibited 7 different phyla of bacteria and 20 different genera. Statistical analysis (Shannon-Weaver Diversity Index and Simpson Diversity Index) of the biodiversity of L27C displayed a moderately rich and diverse community. Investigations of the biodiversity and distribution of microorganisms in these lakes will help further our understanding of how the physical environment impact the structure and function within these microbially dominated ecosystems.

Predicting Disturbance-driven Impacts on Ecosystem Services in Coastal Wetlands

NASA Astrophysics Data System (ADS)

Rajan, S.; Crawford, P.; Kleinhuizen, A.; Mortazavi, B.; Sobecky, P.

2017-12-01

Natural and human-induced disturbances pose significant threats to the health and long-term productivity of Alabama coastal wetlands. As wetlands are a vital state resource, decisions on management, restoration, and remediation require actionable data if socio-economic demands are to be balanced with efforts to sustain these habitats. In 2010, the BP oil spill was a large and severe disturbance that threatened coastal Gulf ecosystem services. The largest marine oil spill to date served to highlight fundamental gaps in our knowledge of oil-induced disturbances and the resiliency and restoration of coastal Alabama wetland functions. To address these gaps, a year-long mesocosm study was conducted to investigate oil-induced effects on (i) plant-microbial interactions, (ii) microbial and plant biodiversity, and, (iii) the contributions of microbial genetic biodiversity to ecosystems services. In this study, Avicennia germinans (black mangrove), a C3 plant that grows from the tropics to warm temperate latitudes, were grown with or without mono- and polyculture mixtures of Spartina alterniflora, a C4 plant. At an interval of 3-months, oil was introduced as a pulse disturbance to achieve a concentration of 4000 ppm. Molecular-based analyses of microbial community biodiversity, genetic diversity, and functional metabolic genes were compared to controls (i.e., no oil disturbance). To assess the oil-induced effects on the nitrogen (N) cycle, measurements of denitrification and N fixation processes were conducted. Our results showed that community diversity and phylogenetic diversity significantly changed and that the oil disturbance contributed to the creation of niches for distinct microbial types. The abundance of N-fixing microbial types increased as the abundance of denitrifying microbial types decreased as a result of the oil disturbance. As denitrification is an ecosystem service that directly contributes to removing nitrate (NO3-) loading to coastal zones, impairment of this process is detrimental to the long-term health and productivity of the Gulf of Mexico. Our results are designed to investigate controlling factors and yield insights to aid decision-makers in their ongoing management efforts to restore wetlands along the Alabama coast and elsewhere.

Scale up of diesel oil biodegradation in a baffled roller bioreactor.

PubMed

Nikakhtari, Hossein; Song, Wanning; Kumar, Pardeep; Nemati, Mehdi; Hill, Gordon A

2010-05-01

Diesel oil is a suitable substance to represent petroleum contamination from accidental spills in operating and transportation facilities. Using a microbial culture enriched from a petroleum contaminated soil, biodegradation of diesel oil was carried out in 2.2, 55, and 220 L roller baffled bioreactors. The effects of bioreactor rotation speed (from 5 to 45 rpm) and liquid loading (from 18% to 73% of total volume) on the biodegradation of diesel oil were studied. In the small scale bioreactor (2.2L), the maximum rotation speed of 45 rpm resulted in the highest biodegradation rate with a first order biodegradation kinetic constant of 0.095 d(-1). In the larger scale bioreactors, rotation speed did not affect the biodegradation rate. Liquid loadings higher than 64% resulted in reduced biodegradation rates in the small scale bioreactor; however, in the larger roller bioreactors liquid loading did not affect the biodegradation rate. Biodegradation of diesel oil at 5 rpm and 73% loading is recommended for operating large scale roller baffled bioreactors. Under these conditions, high diesel oil concentrations up to 50 gL(-1) can be bioremediated at a rate of 1.61 gL(-1)d(-1). Copyright 2010 Elsevier Ltd. All rights reserved.

Enhancing antioxidant activity, microbial and sensory quality of mango (Mangifera indica L.) juice by γ-irradiation and its in vitro radioprotective potential.

PubMed

Naresh, Kondapalli; Varakumar, Sadineni; Variyar, Prasad Shekhar; Sharma, Arun; Reddy, Obulam Vijaya Sarathi

2015-07-01

Gamma irradiation is an effective method currently being used for microbial decontamination and insect disinfestations of foods. In the present study, mango (Mangifera indica L.) juice was irradiated at doses of 0, 1.0, 3.0 and 5.0 kGy and microbial load, total polyphenols, flavonoids, ascorbic acid content, antioxidant activities, colour and sensory properties were evaluated immediately after irradiation and also during storage. Microbiological assay of the fresh and stored mango juice showed better quality after γ-irradiation. The total polyphenols and flavonoids were significantly (p < 0.05) increased while the ascorbic acid content decreased with the irradiation doses applied. As a result of γ-irradiation, a significant increment in gallic, syringic and chlorogenic acids and a significant reduction in ferulic and synapic acids were noted when analyzed by HPLC. In vitro antioxidant potentials were measured using DPPH, FRAP and NO scavenging assays; the results showed significant enhancement in the activities after irradiation, that correlated well with the increase in phenolic and flavonoid content. γ-irradiation improved the colour of mango juice without any adverse changes in the sensory qualities. Significant in vitro plasmid DNA protection was observed in the presence of mango juice against radiation induced damage, even at the dose of 5 kGy. This study confirmed the potential of γ-irradiation as a method for microbial decontamination and improving the quality of the mango juice without compromising on the sensory attributes.

Analysis of extracellular polymeric substances (EPS) and ciprofloxacin-degrading microbial community in the combined Fe-C micro-electrolysis-UBAF process for the elimination of high-level ciprofloxacin.

PubMed

Zhang, Longlong; Yue, Qinyan; Yang, Kunlun; Zhao, Pin; Gao, Baoyu

2018-02-01

Extracellular polymeric substances (EPS) and ciprofloxacin-degrading microbial community in the combined Fe-C micro-electrolysis and up-flow biological aerated filter (UBAF) process for the treatment of high-level ciprofloxacin (CIP) were analyzed. The research demonstrated a great potential of Fe-C micro-electrolysis-UBAF for the elimination of high-level CIP. Above 90% of CIP removal was achieved through the combined process at 100 mg L -1 of CIP loading. In UBAF, the pollutants were mainly removed at 0-70 cm heights. Three-dimensional fluorescence spectrum (3D-EEM) was used to characterize the chemical structural of loosely bound EPS (LB-EPS) and tightly bound EPS (TB-EPS) extracted from biofilm sample in UBAF. The results showed that the protein-like substances in LB-EPS and TB-EPS had no clear change in the study. Nevertheless, an obvious release of polysaccharides in EPSs was observed during long-term exposure to CIP, which was considered as a protective response of microbial to CIP toxic. The high-throughput sequencing results revealed that the biodiversity of bacteria community became increasingly rich with gradual ciprofloxacin biodegradation in UBAF. The ciprofloxacin-degrading microbial community was mainly dominated by Proteobacteria and Bacteroidetes. Microorganisms from genera Dechloromonas, Brevundimonas, Flavobacterium, Sphingopyxis and Bosea might take a major role in ciprofloxacin degradation. This study provides deep theoretical guidance for real CIP wastewater treatment. Copyright © 2017. Published by Elsevier Ltd.

Magazines in waiting areas of hospital: a forgotten microbial reservoir?

PubMed

Adé, Mathias; Burger, Sandrine; Cuntzmann, Anaelle; Exinger, Julien; Meunier, Olivier

2017-12-01

The hospital environment is a potential source of microbial contamination. Thus, the magazines in hospital's waiting rooms are handled by patients and visitors whose health and hygiene conditions can vary widely. In this context, we had measured the microbial load on the surface of magazines. Fifteen magazines from 5 waiting rooms of hospital are sampled by agar prints at the areas taken in hand. The agar plates are incubated at 30̊C for 72h. The colonies are counted and identified by MALDI-TOF mass spectrometry (Vitek ® -MS). The extraction efficiency of bacteria by the agar print method on the magazines is calculated. All the samples highlight a varied bacterial flora: 32CFU/agar in mean. Isolated bacteria come principally from the skin flora (>60%), but we also isolate potentially pathogenic micro-organisme like S. aureus, E. faecalis, A. viridans and Aspergillus sp. as well as oropharyngeal flora bacteria like A. iwolfii and M. osloensis and fecal like B. stercoris. Some species rarely described in hospital are also isolated such as P. yeei or K. sedentarius. The extraction efficiency of the sampling method on a magazine is 36%. Our study, which is the first to be interested in the bacterial contamination of magazines in hospital, could make them consider as microbial reservoir to be controlled, especially for the most fragile patients. New bacterial identification techniques as the MALDI-TOF allow to reveal the presence of rarely described and often underestimated species.

Effect of incorporation of fermented bamboo shoot on physicochemical and microbial quality of pork pickle.

PubMed

Chavhan, D M; Hazarika, M; Brahma, M L; Hazarika, R A; Rahman, Z

2015-02-01

Replacement of commercial chemical preservative (Vinegar) by incorporating fermented bamboo shoot (FBS) products partially or completely and their effect on physicochemical, microbial and shelf life qualities on pork pickle products was studied. Different FBS products such as FBS extract, paste and powder were incorporated in the pork pickle products at the level of 50 to 100 % with or without vinegar and stored at room temperature for 90 days. Highest pH values and lowest titrable acidity was recorded in products with 50 and 100 % FBS powder. No significant differences were observed with respect to proximate composition i.e. percent moisture, protein, fat and ash contents among the products except the product with 100 % FBS powder which had significantly (p < 0.01) lower moisture content. Microbial load (Log total plate counts) and thiobarbituric acid (TBA) values were found to be increasing as the storage periods were advancing. Except the product with 100 % FBS powder which could be stored for 30 days only, other products could be stored upto 90 days without any physicochemical and microbial problems. It can be concluded from this study that natural and organic FBS extract and paste can be used successfully replacing the conventional chemical preservative (Vinegar) for preparation of pork pickle products and preserved more than 90 days at room temperature. However, FBS powder can be used for preservation of the pickle products for a short period (30 days).

Biogeochemistry of the coupled manganese-iron-sulfur cycles of intertidal surface sediments

NASA Astrophysics Data System (ADS)

Bosselmann, K.; Boettcher, M. E.; Billerbeck, M.; Walpersdorf, E.; Debeer, D.; Brumsack, H.-J.; Huettel, M.; Joergensen, B. B.

2003-04-01

The biogeochemistry of the coupled iron-manganese-sulfur-carbon cycles was studied in temperate intertidal surface sediments of the German Wadden Sea (North Sea). Coastal sampling sites include sand, mixed and mud flats with different organic matter and metal contents and permeability reflecting different hydrodynamic regimes. The field study focusses on the influence of temperature, organic matter load, and sediment types on the dynamics of biogeochemical reactions on different time scales (season, day-night, tidal cycles). One of the main interests was related to the cycling of metals (Mn, Fe) in relation to the activity of sulfate-reducing bacteria. Pore water profiles were investigated by sediment sectioning and high resolution gel sampling techniques. Microbial sulfate reduction rates were measured using radiolabeled sulfate with the whole core incubation technique and the spatial distribution of bacterial activity was visualised by using "2D-photoemulsion-monitoring technique". The biogeochemical sulfur cycle was additionally characterised by the stable isotope ratios (S,O) of different sulfur species (e.g., SO_4, AVS, pyrite). Element transfers (metals, nutrients) across the sediment-water interface were additionally quantified by the application of benthic flux chambers. Microbial sulfate reduction was generally highest in the suboxic zone of the surface sediments indicating its potential importance for the mobilization of iron and manganese. In organic matter poor permeable sediments tidal effects additionally influence the spatial and temporal distribution of dissolved redox-sensitive metals. In organic matter-rich silty and muddy sediments, temperature controlled the microbial sulfate reduction rates. Depth-integrated sulfate reduction rates in sandy sediments were much lower and controlled by both temperature and organic matter. Formation of anoxic sediment surfaces due to local enhanced organic matter load (so-called "black spots") may create windows of an increase flux of metals, nutrients and hydrogen sulfide. Acknowledgements: The study was supported by German Science Foundation within the DFG-research group "BioGeoChemistry of the Waddensea" and Max Planck Society.

Prevalence and Antimicrobial Susceptibility of Vibrio parahaemolyticus Isolated from Short Mackerels (Rastrelliger brachysoma) in Malaysia

PubMed Central

Tan, Chia W.; Malcolm, Tan T. H.; Kuan, Chee H.; Thung, Tze Y.; Chang, Wei S.; Loo, Yuet Y.; Premarathne, Jayasekara M. K. J. K.; Ramzi, Othman B.; Norshafawatie, Mohd F. S.; Yusralimuna, Nordin; Rukayadi, Yaya; Nakaguchi, Yoshitsugu; Nishibuchi, Mitsuaki; Radu, Son

2017-01-01

Numerous prevalence studies and outbreaks of Vibrio parahaemolyticus infection have been extensively reported in shellfish and crustaceans. Information on the quantitative detection of V. parahaemolyticus in finfish species is limited. In this study, short mackerels (Rastrelliger brachysoma) obtained from different retail marketplaces were monitored with the presence of total and pathogenic strains of V. parahaemolyticus. Out of 130 short mackerel samples, 116 (89.2%) were detected with the presence of total V. parahaemolyticus and microbial loads of total V. parahaemolyticus ranging from <3 to >105 MPN/g. Prevalence of total V. parahaemolyticus was found highest in wet markets (95.2%) followed by minimarkets (89.1%) and hypermarkets (83.3%). Pathogenic V. parahaemolyticus strains (tdh+ and/or trh+) were detected in 16.2% (21 of 130) of short mackerel samples. The density of tdh+ V. parahaemolyticus strains were examined ranging from 3.6 to >105 MPN/g and microbial loads of V. parahaemolyticus strains positive for both tdh and trh were found ranging from 300 to 740 MPN/g. On the other hand, antibiotic susceptibility profiles of V. parahaemolyticus strains isolated from short mackerels were determined through disc diffusion method in this study. Assessment of antimicrobial susceptibility profile of V. parahaemolyticus revealed majority of the isolates were highly susceptible to ampicillin sulbactam, meropenem, ceftazidime, and imipenem, but resistant to penicillin G and ampicillin. Two isolates (2.99%) exhibited the highest multiple antibiotic resistance (MAR) index value of 0.41 which shown resistance to 7 antibiotics. Results of the present study demonstrated that the occurrence of pathogenic V. parahaemolyticus strains in short mackerels and multidrug resistance of V. parahaemolyticus isolates could be a potential public health concerns to the consumer. Furthermore, prevalence data attained from the current study can be further used to develop a microbial risk assessment model to estimate health risks associated with the consumption of short mackerels contaminated with pathogenic V. parahaemolyticus. PMID:28659901

The plasma levels of soluble ST2 as a marker of gut mucosal damage in early HIV infection

PubMed Central

Mehraj, Vikram; Jenabian, Mohammad-Ali; Ponte, Rosalie; Lebouché, Bertrand; Costiniuk, Cecilia; Thomas, Réjean; Baril, Jean-Guy; LeBlanc, Roger; Cox, Joseph; Tremblay, Cécile; Routy, Jean-Pierre

2016-01-01

Objective: Following tissue barrier breaches, interleukin-33 (IL-33) is released as an ‘alarmin’ to induce inflammation. Soluble suppression of tumorigenicity 2 (sST2), as an IL-33 decoy receptor, contributes to limit inflammation. We assessed the relationship between the IL-33/ST2 axis and markers of gut mucosal damage in patients with early (EHI) and chronic HIV infection (CHI) and elite controllers. Design: Analyses on patients with EHI and CHI were conducted to determine IL-33/sST2 changes over time. Methods: IL-33 and sST2 levels were measured in plasma. Correlations between sST2 levels and plasma viral load, CD4+ and CD8+ T-cell counts, expression of T-cell activation/exhaustion markers, gut mucosal damage, microbial translocation and inflammation markers, as well as kynurenine/tryptophan ratio were assessed. Results: Plasma sST2 levels were elevated in EHI compared with untreated CHI and uninfected controls, whereas IL-33 levels were comparable in all groups. In EHI, sST2 levels were positively correlated with the CD8+ T-cell count and the percentage of T cells expressing activation and exhaustion markers, but not with viral load or CD4+ T-cell count. Plasma sST2 levels also correlated with plasma levels of gut mucosal damage, microbial translocation and kynurenine/tryptophan ratio and for some markers of inflammation. Prospective analyses showed that early antiretroviral therapy had no impact on sST2 levels, whereas longer treatment duration initiated during CHI normalized sST2. Conclusion: As sST2 levels were elevated in EHI and were correlated with CD8+ T-cell count, immune activation, and microbial translocation, sST2 may serve as a marker of disease progression, gut damage and may directly contribute to HIV pathogenesis. PMID:27045377

Influence of housing systems on microbial load and antimicrobial resistance patterns of Escherichia coli isolates from eggs produced for human consumption.

PubMed

Alvarez-Fernández, Elena; Domínguez-Rodríguez, Jessica; Capita, Rosa; Alonso-Calleja, Carlos

2012-05-01

Microbial counts (aerobic bacteria, psychrotrophs, Enterobacteriaceae, coliforms, Pseudomonas spp., Enterococcus spp., Staphylococcus spp., and molds and yeasts) were obtained for the shells of 240 table eggs in northwestern Spain. Eggs from six sources (40 samples in each) were analyzed: chicken eggs from five different housing systems (conventional battery cages, barn, free range, organic, and domestic breeding) and quail eggs (cages). A total of 120 Escherichia coli strains (20 from each source) were tested by the disk diffusion method for resistance to 12 antimicrobial drugs of veterinary and human health significance. Aerobic plate counts ranged from 1.96 ± 1.0 (barn) to 3.69 ± 0.7 (domestic) log CFU/cm(2). Counts for most microbial groups differed significantly between sources. Eggs from domestic production had the highest contamination loads (P < 0.05) for aerobic bacteria, Enterococcus spp., and molds and yeasts and the highest prevalence of E. coli. Twenty-three E. coli isolates (19.17%) were susceptible to all antimicrobials tested, and 80.83 % were resistant to one (22.50%) or more (58.33%) antimicrobials. The housing system had a significant influence (P < 0.05) on the average resistance per strain, with the highest resistance in conventional cage (2.85) and barn (3.10) systems followed by free range (1.55) and quail (1.95). Eggs from organic (1.00) and domestic (0.75) production systems had the lowest resistance per strain. The highest prevalence of resistance was observed for the groups of antimicrobials more frequently used on poultry farms. Our results suggest that a relationship exists between the prevalence of antimicrobial resistance in E. coli strains and the more frequent use of antimicrobials in conventional (cage, barn, and free range) than in domestic and organic chicken housing systems. Education covering good sanitary practices for handling eggs to avoid cross-contamination or inadequate cooking is needed.

Prevalence and Antimicrobial Susceptibility of Vibrio parahaemolyticus Isolated from Short Mackerels (Rastrelliger brachysoma) in Malaysia.

PubMed

Tan, Chia W; Malcolm, Tan T H; Kuan, Chee H; Thung, Tze Y; Chang, Wei S; Loo, Yuet Y; Premarathne, Jayasekara M K J K; Ramzi, Othman B; Norshafawatie, Mohd F S; Yusralimuna, Nordin; Rukayadi, Yaya; Nakaguchi, Yoshitsugu; Nishibuchi, Mitsuaki; Radu, Son

2017-01-01

Numerous prevalence studies and outbreaks of Vibrio parahaemolyticus infection have been extensively reported in shellfish and crustaceans. Information on the quantitative detection of V. parahaemolyticus in finfish species is limited. In this study, short mackerels ( Rastrelliger brachysoma ) obtained from different retail marketplaces were monitored with the presence of total and pathogenic strains of V. parahaemolyticus . Out of 130 short mackerel samples, 116 (89.2%) were detected with the presence of total V. parahaemolyticus and microbial loads of total V. parahaemolyticus ranging from <3 to >10 5 MPN/g. Prevalence of total V. parahaemolyticus was found highest in wet markets (95.2%) followed by minimarkets (89.1%) and hypermarkets (83.3%). Pathogenic V. parahaemolyticus strains ( tdh + and/or trh +) were detected in 16.2% (21 of 130) of short mackerel samples. The density of tdh + V. parahaemolyticus strains were examined ranging from 3.6 to >10 5 MPN/g and microbial loads of V. parahaemolyticus strains positive for both tdh and trh were found ranging from 300 to 740 MPN/g. On the other hand, antibiotic susceptibility profiles of V. parahaemolyticus strains isolated from short mackerels were determined through disc diffusion method in this study. Assessment of antimicrobial susceptibility profile of V. parahaemolyticus revealed majority of the isolates were highly susceptible to ampicillin sulbactam, meropenem, ceftazidime, and imipenem, but resistant to penicillin G and ampicillin. Two isolates (2.99%) exhibited the highest multiple antibiotic resistance (MAR) index value of 0.41 which shown resistance to 7 antibiotics. Results of the present study demonstrated that the occurrence of pathogenic V. parahaemolyticus strains in short mackerels and multidrug resistance of V. parahaemolyticus isolates could be a potential public health concerns to the consumer. Furthermore, prevalence data attained from the current study can be further used to develop a microbial risk assessment model to estimate health risks associated with the consumption of short mackerels contaminated with pathogenic V. parahaemolyticus .

An ex situ evaluation of TBA- and MTBE-baited bio-traps.

PubMed

North, Katharine P; Mackay, Douglas M; Annable, Michael D; Sublette, Kerry L; Davis, Greg; Holland, Reef B; Petersen, Daniel; Scow, Kate M

2012-08-01

Aquifer microbial communities can be investigated using Bio-traps(®) ("bio-traps"), passive samplers containing Bio-Sep(®) beads ("bio-beads") that are deployed in monitoring wells to be colonized by bacteria delivered via groundwater flow through the well. When bio-beads are "baited" with organic contaminants enriched in (13)C, stable isotope probing allows assessment of the composition and activity of the microbial community. This study used an ex situ system fed by groundwater continuously extracted from an adjacent monitoring well within an experimentally-created aerobic zone treating a tert-butyl alcohol (TBA) plume. The goal was to evaluate aspects of bio-trap performance that cannot be studied quantitatively in situ. The measured groundwater flow through a bio-trap housing suggests that such traps might typically "sample" about 1.8 L per month. The desorption of TBA or methyl tert-butyl ether (MTBE) bait from bio-traps during a typical deployment duration of 6 weeks was approximately 90% and 45%, respectively, of the total initial bait load, with initially high rate of mass loss that decreased markedly after a few days. The concentration of TBA in groundwater flowing by the TBA-baited bio-beads was estimated to be as high as 3400 mg/L during the first few days, which would be expected to inhibit growth of TBA-degrading microbes. Initial inhibition was also implied for the MTBE-baited bio-trap, but at lower concentrations and for a shorter time. After a few days, concentrations in groundwater flowing through the bio-traps dropped below inhibitory concentrations but remained 4-5 orders of magnitude higher than TBA or MTBE concentrations within the aquifer at the experimental site. Desorption from the bio-beads during ex situ deployment occurred at first as predicted by prior sorption analyses of bio-beads but with apparent hysteresis thereafter, possibly due to mass transfer limitations caused by colonizing microbes. These results suggest that TBA- or MTBE-baited bio-traps could be baited at lower initial total mass loading with no detriment to trapping ability. The bio-traps were able to collect detectable amounts of microbial DNA and thus allow some insight into the sparse microbial community present in the aquifer during remediation of the low concentration plume. Copyright © 2012 Elsevier Ltd. All rights reserved.

An ex situ evaluation of TBA- and MTBE-baited bio-traps

PubMed Central

North, Katharine P.; Mackay, Douglas M.; Annable, Michael D.; Sublette, Kerry L.; Davis, Greg; Holland, Reef B.; Petersen, Daniel; Scow, Kate M.

2013-01-01

Aquifer microbial communities can be investigated using Bio-traps® (“bio-traps”), passive samplers containing Bio-Sep® beads (“bio-beads”) that are deployed in monitoring wells to be colonized by bacteria delivered via groundwater flow through the well. When bio-beads are “baited” with organic contaminants enriched in 13C, stable isotope probing allows assessment of the composition and activity of the microbial community. This study used an ex situ system fed by groundwater continuously extracted from an adjacent monitoring well within an experimentally-created aerobic zone treating a tert-butyl alcohol (TBA) plume. The goal was to evaluate aspects of bio-trap performance that cannot be studied quantitatively in situ. The measured groundwater flow through a bio-trap housing suggests that such traps might typically “sample” about 1.8 L per month. The desorption of TBA or methyl tert-butyl ether (MTBE) bait from bio-traps during a typical deployment duration of 6 weeks was approximately 90% and 45%, respectively, of the total initial bait load, with initially high rate of mass loss that decreased markedly after a few days. The concentration of TBA in groundwater flowing by the TBA-baited bio-beads was estimated to be as high as 3400 mg/L during the first few days, which would be expected to inhibit growth of TBA-degrading microbes. Initial inhibition was also implied for the MTBE-baited bio-trap, but at lower concentrations and for a shorter time. After a few days, concentrations in groundwater flowing through the bio-traps dropped below inhibitory concentrations but remained 4–5 orders of magnitude higher than TBA or MTBE concentrations within the aquifer at the experimental site. Desorption from the bio-beads during ex situ deployment occurred at first as predicted by prior sorption analyses of bio-beads but with apparent hysteresis thereafter, possibly due to mass transfer limitations caused by colonizing microbes. These results suggest that TBA- or MTBE-baited bio-traps could be baited at lower initial total mass loading with no detriment to trapping ability. The bio-traps were able to collect detectable amounts of microbial DNA and thus allow some insight into the sparse microbial community present in the aquifer during remediation of the low concentration plume. PMID:22621895

Methodology for analyzing environmental quality indicators in a dynamic operating room environment.

PubMed

Gormley, Thomas; Markel, Troy A; Jones, Howard W; Wagner, Jennifer; Greeley, Damon; Clarke, James H; Abkowitz, Mark; Ostojic, John

2017-04-01

Sufficient quantities of quality air and controlled, unidirectional flow are important elements in providing a safe building environment for operating rooms. To make dynamic assessments of an operating room environment, a validated method of testing the multiple factors influencing the air quality in health care settings needed to be constructed. These include the following: temperature, humidity, particle load, number of microbial contaminants, pressurization, air velocity, and air distribution. The team developed the name environmental quality indicators (EQIs) to describe the overall air quality based on the actual measurements of these properties taken during the mock surgical procedures. These indicators were measured at 3 different hospitals during mock surgical procedures to simulate actual operating room conditions. EQIs included microbial assessments at the operating table and the back instrument table and real-time analysis of particle counts at 9 different defined locations in the operating suites. Air velocities were measured at the face of the supply diffusers, at the sterile field, at the back table, and at a return grille. The testing protocol provided consistent and comparable measurements of air quality indicators between institutions. At 20 air changes per hour (ACH), and an average temperature of 66.3°F, the median of the microbial contaminants for the 3 operating room sites ranged from 3-22 colony forming units (CFU)/m 3 at the sterile field and 5-27 CFU/m 3 at the back table. At 20 ACH, the median levels of the 0.5-µm particles at the 3 sites were 85,079, 85,325, and 912,232 in particles per cubic meter, with a predictable increase in particle load in the non-high-efficiency particulate air-filtered operating room site. Using a comparison with cleanroom standards, the microbial and particle counts in all 3 operating rooms were equivalent to International Organization for Standardization classifications 7 and 8 during the mock surgical procedures. The EQI protocol was measurable and repeatable and therefore can be safely used to evaluate air quality within the health care environment to provide guidance for operational practices and regulatory requirements. Copyright © 2017 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

Geohydrology, water quality, and nitrogen geochemistry in the saturated and unsaturated zones beneath various land uses, Riverside and San Bernardino counties, California, 1991-93

USGS Publications Warehouse

Rees, Terry F.; Bright, Daniel J.; Fay, Ronald G.; Christensen, Allen H.; Anders, Robert; Baharie, Brian S.; Land, Michael T.

1995-01-01

The U.S. Geological Survey, in cooperation with the Eastern Municipal Water District, the Metropolitan Water District of Southern California, and the Orange County Water District, has completed a detailed study of the Hemet groundwater basin. The quantity of ground water stored in the basin in August 1992 is estimated to be 327,000 acre-feet. Dissolved-solids concentration ranged from 380 to 700 mg/L (milligrams per liter), except in small areas where the concentration exceeded 1,000 mg/L. Nitrate concentrations exceeded the U.S. Environmental Protection Agency Maximum Contaminant Level (MCL) of 10 mg/L nitrate (as nitrogen) in the southeastern part of the basin, in the Domenigoni Valley area, and beneath a dairy in the Diamond Valley area. Seven sites representing selected land uses-- residential, turf grass irrigated with reclaimed water, citrus grove, irrigated farm, poultry farm, and dairy (two sites)--were selected for detailed study of nitrogen geochemistry in the unsaturated zone. For all land uses, nitrate was the dominant nitrogen species in the unsaturated zone.Although nitrate was seasonally present in the shallow unsaturated zone beneath the residential site, it was absent at moderate depths, suggesting negligible migration of nitrate from the surface at this time. Microbial denitrification probably is occurring in the shallow unsaturated zone. High nitrate concentrations in the deep unsaturated zone (greater than 100 ft) suggest either significantly higher nitrate loading at some time in the past, or lateral movement of nitrate at depth. Nitrate also is seasonally present in the shallow unsaturated zone beneath the reclaimed-water site, and (in contrast with the residential site), nitrate is perennially present in the deeper unsaturated zone. Microbial denitrification in the unsaturated zone and in the capillary fringe above the water table decreases the concentrations of nitrate in pore water to below the MCL before reaching the water table.Pore water in the unsaturated zone beneath the citrus grove site contains very high concentrations of nitrate. Even though there are zones of microbial denitrification, nitrate seems to be migrating downward to the water table. The presence of a shallow perched-water zone beneath the irrigated-farm site prevents the vertical movement of nitrate from the surface to the regional water table. Above the perched zone, nitrate concentrations in the unsaturated zone are variable, ranging from below the MCL to four times the MCL. Periodically, nitrate is flushed from the shallow unsaturated zone to the perched-water zone. The unsaturated zone pore-moisture quality could not be adequately addressed because of the very dry conditions in the unsaturated zone beneath the poultry-farm site. Surficial clay deposits prevent water from percolating downward.At the two dairy sites, nitrate loading in pore water at the surface was very high, as great as 7,000 mg/L. Microbial denitrification in the unsaturated zone causes such concentrations to decrease rapidly with depth. At a depth of 20 ft, nitrate concentration was less than 100 mg/L. In areas where the depth to water is less than 20 ft, nitrate loading to ground water can be very high, whereas in areas where depth to water is greater than 100 ft, most of the nitrate is microbially removed before reaching the water table.

Experimental method for estimation of compaction in the Oxfordian bedded limestones of the southern Kraków-Częstochowa Upland, Southern Poland

NASA Astrophysics Data System (ADS)

Kochman, Alicja; Matyszkiewicz, Jacek

2013-12-01

Kochman, A. and Matyszkiewicz, J. 2013. Experimental method for estimation of compaction in the Oxfordian bedded limestones of the southern Krakow-Częstochowa Upland, Southern Poland. Acta Geologica Polonica, 63(4), 681-696. Warszawa. The Upper Jurassic carbonates exposed in the southern part of the Krakow-Częstochowa Upland are well known for their significant facies diversity related to the presence of microbial and microbial-sponge carbonate buildups and bedded detrital limestone in between. Both the buildups and detrital limestones revealed differential susceptibility to compaction which, apart from differential subsidence of the Palaeozoic basement and synsedimentary faulting, was one of the factors controlling seafloor palaeorelief in the Late Jurassic sedimentary basin. The compaction of the detrital limestones has been estimated with an experimental oedometric method in which specially prepared mixtures made of ground limestones from a quarry in the village of Żary were subjected to oedometer tests. The diameters of the detrital grains and their percentages in the limestones were determined by microscopic examinations of thin sections. The diameters were assigned to predetermined classes corresponding to the Udden-Wentworth scale. The rock samples were then ground down to the grain sizes observed in thin sections. From such materials, mixtures were prepared of grain size distributions corresponding to those observed in thin sections. After adding water the mixtures were subjected to oedometer tests. Analysis of the compression of such mixtures under specific loads enabled preparation of a mathematical formula suitable for the estimation of mechanical compaction of the limestone. The obtained values varied from 27.52 to 55.53% for a load corresponding to 300 metres burial depth. The most significant effect of mechanical compaction was observed for loads representing only 2 metres burial depth. Further loading resulted in a much smaller reduction in sample height. The results of the oedometer tests cannot be used directly to determine compaction of the detrital limestones. Mainly because microscopic observations of thin sections of the experimental material show that chemical compaction was also an important factor influencing thickness reduction of the limestones.

Methylene Blue-Loaded Dissolving Microneedles: Potential Use in Photodynamic Antimicrobial Chemotherapy of Infected Wounds

PubMed Central

Caffarel-Salvador, Ester; Kearney, Mary-Carmel; Mairs, Rachel; Gallo, Luigi; Stewart, Sarah A.; Brady, Aaron J.; Donnelly, Ryan F.

2015-01-01

Photodynamic therapy involves delivery of a photosensitising drug that is activated by light of a specific wavelength, resulting in generation of highly reactive radicals. This activated species can cause destruction of targeted cells. Application of this process for treatment of microbial infections has been termed “photodynamic antimicrobial chemotherapy” (PACT). In the treatment of chronic wounds, the delivery of photosensitising agents is often impeded by the presence of a thick hyperkeratotic/necrotic tissue layer, reducing their therapeutic efficacy. Microneedles (MNs) are an emerging drug delivery technology that have been demonstrated to successfully penetrate the outer layers of the skin, whilst minimising damage to skin barrier function. Delivering photosensitising drugs using this platform has been demonstrated to have several advantages over conventional photodynamic therapy, such as, painless application, reduced erythema, enhanced cosmetic results and improved intradermal delivery. The aim of this study was to physically characterise dissolving MNs loaded with the photosensitising agent, methylene blue and assess their photodynamic antimicrobial activity. Dissolving MNs were fabricated from aqueous blends of Gantrez® AN-139 co-polymer containing varying loadings of methylene blue. A height reduction of 29.8% was observed for MNs prepared from blends containing 0.5% w/w methylene blue following application of a total force of 70.56 N/array. A previously validated insertion test was used to assess the effect of drug loading on MN insertion into a wound model. Staphylococcus aureus, Escherichia coli and Candida albicans biofilms were incubated with various methylene blue concentrations within the range delivered by MNs in vitro (0.1–2.5 mg/mL) and either irradiated at 635 nm using a Paterson Lamp or subjected to a dark period. Microbial susceptibility to PACT was determined by assessing the total viable count. Kill rates of >96%, were achieved for S. aureus and >99% for E. coli and C. albicans with the combination of PACT and methylene blue concentrations between 0.1 and 2.5 mg/mL. A reduction in the colony count was also observed when incorporating the photosensitiser without irradiation, this reduction was more notable in S. aureus and E. coli strains than in C. albicans. PMID:26426040

Integrated waste and water management system

NASA Technical Reports Server (NTRS)

Murray, R. W.; Sauer, R. L.

1986-01-01

The performance requirements of the NASA Space Station have prompted a reexamination of a previously developed integrated waste and water management system that used distillation and catalytic oxydation to purify waste water, and microbial digestion and incineration for waste solids disposal. This system successfully operated continuously for 206 days, for a 4-man equivalent load of urine, feces, wash water, condensate, and trash. Attention is given to synergisms that could be established with other life support systems, in the cases of thermal integration, design commonality, and novel technologies.

Electron beam irradiation for biological decontamination of Spirulina platensis

NASA Astrophysics Data System (ADS)

Brasoveanu, Mirela; Nemtanu, Monica; Minea, R.; Grecu, Maria Nicoleta; Mazilu, Elena; Radulescu, Nora

2005-10-01

The Cyanobacterium Spirulina is commercialized for its use in health foods and for therapeutic purposes due to its valuable constituents particularly proteins and vitamins. The aim of the paper is to study the Spirulina platensis behaviour when it is electron beam irradiated for biological decontamination. Microbial load, antioxidant activity, enzymatic inhibition, electron spin resonance (ESR) and UV-Vis spectra were measured for doses up to 80 kGy. The results were correlated with doses in order to find where decontamination is efficient, keeping the Spirulina qualities.