Procalcitonin levels in bloodstream infections caused by different sources and species of bacteria.

Science.gov (United States)

Yan, Sheng Tao; Sun, Li Chao; Jia, Hong Bing; Gao, Wen; Yang, Jian Ping; Zhang, Guo Qiang

2017-04-01

The aim of this study was to evaluate procalcitonin (PCT) diagnostic accuracy in discriminating gram-negative (GN) from gram-positive (GP) bloodstream infections and determining the relationship between PCT levels, infection sites, and pathogen types. Clinical and laboratory data were collected from patients with blood culture (BC)-positive sepsis between January 2014 and December 2015. PCT levels at different infection sites were compared, as was the presence of GN and GP bloodstream infection. A receiver operating characteristic (ROC) curve was generated to assess diagnostic accuracy. Of the 486 monomicrobial BCs, 254 (52.26%) were positive for GN bacteria (GNB), and 202 (42.18%) for GP bacteria (GPB). Median PCT levels were higher in BCs positive for GN (2.42ng/ml, IQR: 0.38-15.52) than in those positive for GPB (0.49ng/ml, IQR: 0.13-5.89) (PAcinetobacter baumanni/Burkholderia cepacia, Klebsiella pneumonia and Acinetobacter baumanni. PCT levels caused by GPB differed between Staphylococcus epidermidis/Staphylococcus aureus and Staphylococcus hominis/Staphylococcus haemolyticus, Enterococcus faecium and Enterococcus faecalis/S.hominis/S. haemolyticus. Among patients with known infection sites, there were statistical differences in PCT levels between abdominal infection and pneumonia/infective endocarditis, urinary tract infection and pneumonia/catheter-related infection/infective endocarditis. PCT can distinguish between GNB and GPB infection, as well as between different bacterial species and infection sites. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Association of Levels of Antibodies from Patients with Inflammatory Bowel Disease with Extracellular Proteins of Food and Probiotic Bacteria

Directory of Open Access Journals (Sweden)

Arancha Hevia

2014-01-01

Full Text Available Inflammatory bowel disease (IBD is an autoimmune disease characterized by a chronic inflammation of the gastrointestinal tract mucosa and is related to an abnormal immune response to commensal bacteria. Our aim of the present work has been to explore the levels of antibodies (IgG and IgA raised against extracellular proteins produced by LAB and its association with IBD. We analyzed, by Western-blot and ELISA, the presence of serum antibodies (IgA and IgG developed against extracellular protein fractions produced by different food bacteria from the genera Bifidobacterium and Lactobacillus. We used a sera collection consisting of healthy individuals (HC, n=50, Crohn's disease patients (CD, n=37, and ulcerative colitis patients (UC, n=15. Levels of IgA antibodies developed against a cell-wall hydrolase from Lactobacillus casei subsp. rhamnosus GG (CWH were significantly higher in the IBD group (P<0.002; n=52. The specificity of our measurements was confirmed by measuring IgA antibodies developed against the CWH peptide 365-VNTSNQTAAVSAS-377. IBD patients appeared to have different immune response to food bacteria. This paper sets the basis for developing systems for early detection of IBD, based on the association of high levels of antibodies developed against extracellular proteins from food and probiotic bacteria.

Clearance of Pseudomonas aeruginosa Foreign-Body Biofilm Infections through Reduction of the Cyclic Di-GMP Level in the Bacteria

DEFF Research Database (Denmark)

Christensen, Louise D.; van Gennip, Maria; Rybtke, Morten Theil

2013-01-01

Opportunistic pathogenic bacteria can engage in biofilm-based infections that evade immune responses and develop into chronic conditions. Because conventional antimicrobials cannot efficiently eradicate biofilms, there is an urgent need to develop alternative measures to combat biofilm infections....... It has recently been established that the secondary messenger cyclic diguanosine monophosphate (c-di-GMP) functions as a positive regulator of biofilm formation in several different bacteria. In the present study we investigated whether manipulation of the c-di-GMP level in bacteria potentially can...... be used for biofilm control in vivo. We constructed a Pseudomonas aeruginosa strain in which a reduction in the c-di-GMP level can be achieved via induction of the Escherichia coli YhjH c-di-GMP phosphodiesterase. Initial experiments showed that induction of yhjH expression led to dispersal...

High-Level Culturability of Epiphytic Bacteria and Frequency of Biosurfactant Producers on Leaves

Science.gov (United States)

Burch, Adrien Y.; Do, Paulina T.; Sbodio, Adrian; Suslow, Trevor V.

2016-01-01

ABSTRACT To better characterize the bacterial community members capable of biosurfactant production on leaves, we distinguished culturable biosurfactant-producing bacteria from nonproducers and used community sequencing to compare the composition of these distinct cultured populations with that from DNA directly recovered from leaves. Communities on spinach, romaine, and head lettuce leaves were compared with communities from adjacent samples of soil and irrigation source water. Soil communities were poorly described by culturing, with recovery of cultured representatives from only 21% of the prevalent operational taxonomic units (OTUs) (>0.2% reads) identified. The dominant biosurfactant producers cultured from soil included bacilli and pseudomonads. In contrast, the cultured communities from leaves are highly representative of the culture-independent communities, with over 85% of the prevalent OTUs recovered. The dominant taxa of surfactant producers from leaves were pseudomonads as well as members of the infrequently studied genus Chryseobacterium. The proportions of bacteria cultured from head lettuce and romaine leaves that produce biosurfactants were directly correlated with the culture-independent proportion of pseudomonads in a given sample, whereas spinach harbored a wider diversity of biosurfactant producers. A subset of the culturable bacteria in irrigation water also became enriched on romaine leaves that were irrigated overhead. Although our study was designed to identify surfactant producers on plants, we also provide evidence that most bacteria in some habitats, such as agronomic plant surfaces, are culturable, and these communities can be readily investigated and described by more classical culturing methods. IMPORTANCE The importance of biosurfactant production to the bacteria that live on waxy leaf surfaces as well as their ability to be accurately assessed using culture-based methodologies was determined by interrogating epiphytic populations by

An architectural approach to level design

CERN Document Server

Totten, Christopher W

2014-01-01

Explore Level Design through the Lens of Architectural and Spatial Experience TheoryWritten by a game developer and professor trained in architecture, An Architectural Approach to Level Design is one of the first books to integrate architectural and spatial design theory with the field of level design. It explores the principles of level design through the context and history of architecture, providing information useful to both academics and game development professionals.Understand Spatial Design Principles for Game Levels in 2D, 3D, and Multiplayer ApplicationsThe book presents architectura

Clostridium Bacteria and Autism Spectrum Conditions: A Systematic Review and Hypothetical Contribution of Environmental Glyphosate Levels

Directory of Open Access Journals (Sweden)

Isadora Argou-Cardozo

2018-04-01

Full Text Available Nowadays, there seems to be a consensus about the multifactorial nature of autism spectrum disorders (ASD. The literature provides hypotheses dealing with numerous environmental factors and genes accounting for the apparently higher prevalence of this condition. Researchers have shown evidence regarding the impact of gut bacteria on neurological outcomes, altering behavior and potentially affecting the onset and/or severity of psychiatric disorders. Pesticides and agrotoxics are also included among this long list of ASD-related environmental stressors. Of note, ingestion of glyphosate (GLY, a broad-spectrum systemic herbicide, can reduce beneficial bacteria in the gastrointestinal tract microbiota without exerting any effects on the Clostridium population, which is highly resistant to this herbicide. In the present study, (i we performed a systematic review to evaluate the relationship between Clostridium bacteria and the probability of developing and/or aggravating autism among children. For that purpose, electronic searches were performed on Medline/PubMed and Scielo databases for identification of relevant studies published in English up to December 2017. Two independent researches selected the studies and analyzed the data. The results of the present systematic review demonstrate an interrelation between Clostridium bacteria colonization of the intestinal tract and autism. Finally, (ii we also hypothesize about how environmental GLY levels may deleteriously influence the gut–brain axis by boosting the growth of Clostridium bacteria in autistic toddlers.

Clostridium Bacteria and Autism Spectrum Conditions: A Systematic Review and Hypothetical Contribution of Environmental Glyphosate Levels.

Science.gov (United States)

Argou-Cardozo, Isadora; Zeidán-Chuliá, Fares

2018-04-04

Nowadays, there seems to be a consensus about the multifactorial nature of autism spectrum disorders (ASD). The literature provides hypotheses dealing with numerous environmental factors and genes accounting for the apparently higher prevalence of this condition. Researchers have shown evidence regarding the impact of gut bacteria on neurological outcomes, altering behavior and potentially affecting the onset and/or severity of psychiatric disorders. Pesticides and agrotoxics are also included among this long list of ASD-related environmental stressors. Of note, ingestion of glyphosate (GLY), a broad-spectrum systemic herbicide, can reduce beneficial bacteria in the gastrointestinal tract microbiota without exerting any effects on the Clostridium population, which is highly resistant to this herbicide. In the present study, (i) we performed a systematic review to evaluate the relationship between Clostridium bacteria and the probability of developing and/or aggravating autism among children. For that purpose, electronic searches were performed on Medline/PubMed and Scielo databases for identification of relevant studies published in English up to December 2017. Two independent researches selected the studies and analyzed the data. The results of the present systematic review demonstrate an interrelation between Clostridium bacteria colonization of the intestinal tract and autism. Finally, (ii) we also hypothesize about how environmental GLY levels may deleteriously influence the gut-brain axis by boosting the growth of Clostridium bacteria in autistic toddlers.

Competitive binding of polyethyleneimine-coated gold nanoparticles to enzymes and bacteria: a key mechanism for low-level colorimetric detection of gram-positive and gram-negative bacteria

International Nuclear Information System (INIS)

Thiramanas, Raweewan; Laocharoensuk, Rawiwan

2016-01-01

The article describes a simple and rapid method for colorimetric detection of bacteria. It is based on competitive binding of positively charged polyethyleneimine-coated gold nanoparticles (PEI-AuNPs) to negatively charged enzymes and bacteria. The PEI-AuNPs are electrostatically attracted by both the bacterial surface and the enzyme β-galactosidase (β-Gal). Binding to the latter results in the inhibition of enzyme activity. However, in the presence of a large number of bacteria, the PEI-AuNPs preferentially bind to bacteria. Hence, the enzyme will not be inhibited and its activity can be colorimetrically determined via hydrolysis of the chromogenic substrate chlorophenol red β-D-galactopyranoside (CPRG). The detection limit of this assay is as low as 10 cfu·mL −1 , and the linear range extends from 10 6 to 10 8 cfu·mL −1 . The assay is applicable to both Gram-negative (such as enterotoxigenic Escherichia coli; ETEC) and Gram-positive (Staphylococcus aureus; S. aureus) bacteria. Results are obtained within 10 min using an optical reader, and within 2–3 h by bare-eye detection. The method was applied to the identification of ETEC contamination at a level of 10 cfu·mL −1 in spiked drinking water. Given its low detection limit and rapidity (sample preconcentration is not required), this method holds great promise for on-site detection of total bacterial contamination. (author)

Resistance of Feather-Associated Bacteria to Intermediate Levels of Ionizing Radiation near Chernobyl

OpenAIRE

Ruiz-Gonz?lez, Mario Xavier; Czirj?k, G?bor ?rp?d; Genevaux, Pierre; M?ller, Anders Pape; Mousseau, Timothy Alexander; Heeb, Philipp

2016-01-01

Ionizing radiation has been shown to produce negative effects on organisms, although little is known about its ecological and evolutionary effects. As a study model, we isolated bacteria associated with feathers from barn swallows Hirundo rustica from three study areas around Chernobyl differing in background ionizing radiation levels and one control study site in Denmark. Each bacterial community was exposed to four different ? radiation doses ranging from 0.46 to 3.96 kGy to test whether ch...

Aggregation-Induced-Emission Materials with Different Electric Charges as an Artificial Tongue: Design, Construction, and Assembly with Various Pathogenic Bacteria for Effective Bacterial Imaging and Discrimination.

Science.gov (United States)

Liu, Guang-Jian; Tian, Sheng-Nan; Li, Cui-Yun; Xing, Guo-Wen; Zhou, Lei

2017-08-30

Imaging-based total bacterial count and type identification of bacteria play crucial roles in clinical diagnostics, public health, biological and medical science, and environmental protection. Herein, we designed and synthesized a series of tetraphenylethenes (TPEs) functionalized with one or two aldehyde, carboxylic acid, and quaternary ammonium groups, which were successfully used as fluorescent materials for rapid and efficient staining of eight kinds of representative bacterial species, including pathogenic bacteria Vibrio cholera, Klebsiella pneumoniae, and Listeria monocytogenes and potential bioterrorism agent Yersinia pestis. By comparing the fluorescence intensity changes of the aggregation-induced-emission (AIE) materials before and after bacteria incubation, the sensing mechanisms (electrostatic versus hydrophobic interactions) were simply discussed. Moreover, the designed AIE materials were successfully used as an efficient artificial tongue for bacteria discrimination, and all of the bacteria tested were identified via linear discriminant analysis. Our current work provided a general method for simultaneous broad-spectrum bacterial imaging and species discrimination, which is helpful for bacteria surveillance in many fields.

System level ESD co-design

CERN Document Server

Gossner, Harald

2015-01-01

An effective and cost efficient protection of electronic system against ESD stress pulses specified by IEC 61000-4-2 is paramount for any system design. This pioneering book presents the collective knowledge of system designers and system testing experts and state-of-the-art techniques for achieving efficient system-level ESD protection, with minimum impact on the system performance. All categories of system failures ranging from ‘hard’ to ‘soft’ types are considered to review simulation and tool applications that can be used. The principal focus of System Level ESD Co-Design is defining and establishing the importance of co-design efforts from both IC supplier and system builder perspectives. ESD designers often face challenges in meeting customers' system-level ESD requirements and, therefore, a clear understanding of the techniques presented here will facilitate effective simulation approaches leading to better solutions without compromising system performance. With contributions from Robert Asht...

Level design concept, theory, and practice

CERN Document Server

Kremers, Rudolf

2009-01-01

Good or bad level design can make or break any game, so it is surprising how little reference material exists for level designers. Beginning level designers have a limited understanding of the tools and techniques they can use to achieve their goals, or even define them. This book is the first to use a conceptual and theoretical foundation to build such a set of practical tools and techniques. It is tied to no particular technology or genre, so it will be a useful reference for many years to come. Kremers covers many concepts universal to level design, such as interactivity, world building, im

Increased levels of deleted in malignant brain tumours 1 (DMBT1) in active bacteria-related appendicitis

DEFF Research Database (Denmark)

Kaemmerer, Elke; Schneider, Ursula; Klaus, Christina

2012-01-01

Kaemmerer E, Schneider U, Klaus C, Plum P, Reinartz A, Adolf M, Renner M, Wolfs T G A M, Kramer B W, Wagner N, Mollenhauer J & Gassler N (2012) Histopathology Increased levels of deleted in malignant brain tumours 1 (DMBT1) in active bacteria-related appendicitis Aims:  Deleted in malignant brain...

Low field orientation magnetic separation methods for magnetotactic bacteria

International Nuclear Information System (INIS)

Moeschler, F.D.

1999-01-01

range of motility inhibiting ions is such that MTB cannot be envisaged for general wastewater applications. Radionucleide studies were undertaken targeting a niche application where this metal ion restriction would not apply. Liquid scintillation and γ-ray counting measurements indicated that magnetotactic bacteria accumulate high levels of both plutonium and mercury. A number of both static and flow recovery separators for magnetotactic bacteria were developed. Statistical models predicting the behaviour of these separators were compared to measured results. These comparisons highlighted the problems of 'wash off' of accumulated bacteria in separators where flow was present. The most successful of the flow recovery designs - the channel separator - was then tested using a simulated effluent that contained plutonium. The results confirmed both previous radioisotope uptake studies and separator test results. The channel separator design was enhanced by the introduction of wire arrays into the separation chamber. Orientation magnetic separation in these hybrid-type separators was used to accumulate the biomass and the magnetic gradients generated by the wire arrays to retain the bacteria on the separator walls. These separators achieved increases in efficiency of up to 300% compared with the channel separator. In summary, this thesis describes a successful separation process for the recovery of motile MTB. However, to apply this separator approach to the suggested radioisotope application would require successful large scale culturing. (author)

[Darwin and bacteria].

Science.gov (United States)

Ledermann D, Walter

2009-02-01

As in 2009 the scientific world celebrates two hundreds years from the birthday of Charles Darwin and one hundred and fifty from the publication of The Origin of Species, an analysis of his complete work is performed, looking for any mention of bacteria. But it seems that the great naturahst never took knowledge about its existence, something rather improbable in a time when the discovery of bacteria shook the medical world, or he deliberately ignored them, not finding a place for such microscopic beings into his theory of evolution. But the bacteria badly affected his familiar life, killing scarlet fever one of his children and worsening to death the evolution of tuberculosis of his favourite Annie. Darwin himself could suffer the sickness of Chagas, whose etiological agent has a similar level to bacteria in the scale of evolution.

Contamination Levels and Identification of Bacteria in Milk Sampled from Three Regions of Tanzania: Evidence from Literature and Laboratory Analyses

Directory of Open Access Journals (Sweden)

G. Msalya

2017-01-01

Full Text Available Milk in Tanzania has been reported to be contaminated with large number of bacteria. This is because (1 milk is obtained from animals with unknown health status, (2 good milking and handling practices are to a large extent not observed, and (3 marketing and distribution are done in informal channels. These factors are potential causes of milk-borne diseases and milk quality loss. The aim of this study was to assess nutritional risks in milk as reported in literature over a period of 20 years and through analyses of samples collected during the present study. The issues highlighted in literature were high bacteria and coliform counts exceeding standard levels in East Africa, prevalence of bacteria and drug residues in milk, and adulteration. Based on performed analyses, total bacterial count 1.0×107 colony forming units per millilitre (cfu/ml and total coliform count 1.1×107 cfu/ml, also greater than recommended levels, were found. Ten bacteria types were isolated from milk samples (five, Pseudomonas aeruginosa, Listeria monocytogenes, Listeria innocua, Listeria ivanovii, and Klebsiella spp. are reported in Tanzanian for the first time. Two drugs tetracycline and sulphur were detected. Therefore, it is worth noting that integrated research is needed to evaluate the situation and address these challenges.

Implementing sponge physiological and genomic information to enhance the diversity of its culturable associated bacteria.

Science.gov (United States)

Lavy, Adi; Keren, Ray; Haber, Markus; Schwartz, Inbar; Ilan, Micha

2014-02-01

In recent years new approaches have emerged for culturing marine environmental bacteria. They include the use of novel culture media, sometimes with very low-nutrient content, and a variety of growth conditions such as temperature, oxygen levels, and different atmospheric pressures. These approaches have largely been neglected when it came to the cultivation of sponge-associated bacteria. Here, we used physiological and environmental conditions to reflect the environment of sponge-associated bacteria along with genomic data of the prominent sponge symbiont Candidatus Poribacteria sp. WGA-4E, to cultivate bacteria from the Red Sea sponge Theonella swinhoei. Designing culturing conditions to fit the metabolic needs of major bacterial taxa present in the sponge, through a combined use of diverse culture media compositions with aerobic and microaerophilic states, and addition of antibiotics, yielded higher diversity of the cultured bacteria and led to the isolation of novel sponge-associated and sponge-specific bacteria. In this work, 59 OTUs of six phyla were isolated. Of these, 22 have no close type strains at the species level (< 97% similarity of 16S rRNA gene sequence), representing novel bacteria species, and some are probably new genera and even families. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

Dielectrophoresis-based discrimination of bacteria at the strain level based on their surface properties.

Directory of Open Access Journals (Sweden)

William A Braff

Full Text Available Insulator-based dielectrophoresis can be used to manipulate biological particles, but has thus far found limited practical applications due to low sensitivity. We present linear sweep three-dimensional insulator-based dielectrophoresis as a considerably more sensitive approach for strain-level discrimination bacteria. In this work, linear sweep three-dimensional insulator-based dielectrophoresis was performed on Pseudomonas aeruginosa PA14 along with six isogenic mutants as well as Streptococcus mitis SF100 and PS344. Strain-level discrimination was achieved between these clinically important pathogens with applied electric fields below 10 V/mm. This low voltage, high sensitivity technique has potential applications in clinical diagnostics as well as microbial physiology research.

Levels and complexity of IgA antibody against oral bacteria in samples of human colostrum.

Science.gov (United States)

Petrechen, L N; Zago, F H; Sesso, M L T; Bertoldo, B B; Silva, C B; Azevedo, K P; de Lima Pereira, S A; Geraldo-Martins, V R; Ferriani, V P L; Nogueira, R D

2015-01-01

Streptococcus mutans (SM) have three main virulence antigens: glucan binding protein B (gbpB), glucosyltransferase (Gtf) and antigens I/II (Ag I/II) envolved in the capacity of those bacteria to adhere and accumulate in the dental biofilm. Also, the glycosyltransferases 153 kDa of Streptococcus gordonii (SGO) and 170kDa of Streptococcus sanguinis (SSA) were important antigens associated with the accumulation of those bacterias. Streptococcus mitis (SMI) present IgA1 protease of 202 kDa. We investigated the specificity and levels IgA against those antigens of virulence in samples of human colostrum. This study involved 77 samples of colostrum that were analyzed for levels of immunoglobulian A, M and G by Elisa. The specificity of IgA against extracts of SM and initials colonizators (SSA, SMI, SGO) were analyzed by the Western blot. The mean concentration of IgA was 2850.2 (±2567.2) mg/100 mL followed by IgM and IgG (respectively 321.8±90.3 and 88.3±51.5), statistically different (pbacteria antigens and theirs virulence antigens. To SM, the GbpB was significantly lower detected than others antigens of SM (p0.4). So, the breast milk from first hours after birth presented significant levels of IgA specific against important virulence of antigens those oral streptococci, which can disrupt the installation and accumulation process of these microorganisms in the oral cavity. Copyright © 2014 Elsevier GmbH. All rights reserved.

Monitoring of airborne bacteria and aerosols in different wards of hospitals - Particle counting usefulness in investigation of airborne bacteria.

Science.gov (United States)

Mirhoseini, Seyed Hamed; Nikaeen, Mahnaz; Khanahmd, Hossein; Hatamzadeh, Maryam; Hassanzadeh, Akbar

2015-01-01

The presence of airborne bacteria in hospital environments is of great concern because of their potential role as a source of hospital-acquired infections (HAI). The aim of this study was the determination and comparison of the concentration of airborne bacteria in different wards of four educational hospitals, and evaluation of whether particle counting could be predictive of airborne bacterial concentration in different wards of a hospital. The study was performed in an operating theatre (OT), intensive care unit (ICU), surgery ward (SW) and internal medicine (IM) ward of four educational hospitals in Isfahan, Iran. A total of 80 samples were analyzed for the presence of airborne bacteria and particle levels. The average level of bacteria ranged from 75-1194 CFU/m (3) . Mean particle levels were higher than class 100,000 cleanrooms in all wards. A significant correlation was observed between the numbers of 1-5 µm particles and levels of airborne bacteria in operating theatres and ICUs. The results showed that factors which may influence the airborne bacterial level in hospital environments should be properly managed to minimize the risk of HAIs especially in operating theaters. Microbial air contamination of hospital settings should be performed by the monitoring of airborne bacteria, but particle counting could be considered as a good operative method for the continuous monitoring of air quality in operating theaters and ICUs where higher risks of infection are suspected.

Students as Math Level Designers

DEFF Research Database (Denmark)

Jensen, Erik Ottar; Hanghøj, Thorkild; Schoenau-Fog, Henrik

The short paper presents preliminary findings from a pilot study on how students become motivated through design of learning games in math. The research is carried out in a Danish public school with two classes of 5th graders (N = 42 students). Over the course of two weeks, the students work...... with a design template for a runner game in the Unity 3D game design engine. The students are introduced to the concept of “flow” (Csikszentmihalyi, 1991) as a game design principle and are asked to design levels for a math runner game, which are both engaging as well as a meaningful way of learning math....... In this way, the students are positioned as “math level designers”, which means that they both have to redesign the difficulty of the runner game as well as the difficulty of the mathematical questions and possible answers....

PCR detection of thermophilic spore-forming bacteria involved in canned food spoilage.

Science.gov (United States)

Prevost, S; Andre, S; Remize, F

2010-12-01

Thermophilic bacteria that form highly heat-resistant spores constitute an important group of spoilage bacteria of low-acid canned food. A PCR assay was developed in order to rapidly trace these bacteria. Three PCR primer pairs were designed from rRNA gene sequences. These primers were evaluated for the specificity and the sensitivity of detection. Two primer pairs allowed detection at the species level of Geobacillus stearothermophilus and Moorella thermoacetica/thermoautrophica. The other pair allowed group-specific detection of anaerobic thermophilic bacteria of the genera Thermoanaerobacterium, Thermoanaerobacter, Caldanerobium and Caldanaerobacter. After a single enrichment step, these PCR assays allowed the detection of 28 thermophiles from 34 cans of spoiled low-acid food. In addition, 13 ingredients were screened for the presence of these bacteria. This PCR assay serves as a detection method for strains able to spoil low-acid canned food treated at 55°C. It will lead to better reactivity in the canning industry. Raw materials and ingredients might be qualified not only for quantitative spore contamination, but also for qualitative contamination by highly heat-resistant spores.

Surface-enhanced Raman scattering detection of bacteria on microarrays at single cell levels using silver nanoparticles

International Nuclear Information System (INIS)

Zhou, Haibo; Yang, Danting; Mircescu, Nicoleta E.; Ivleva, Natalia P.; Schwarzmeier, Kathrin; Niessner, Reinhard; Haisch, Christoph; Wieser, Andreas; Schubert, Sören

2015-01-01

We describe a method for the synthesis of SERS-active silver nanoparticles (AgNPs) directly on the surface of bacteria (bacteria-AgNPs), specifically of E. coli cells. This straightforward strategy allows for the sensitive determination of bacteria on a microarray platform. Antibodies were used as selective receptors on the microarray surface. The Raman signal of bacteria-AgNPs is about 10 times higher than that obtained previously with microarrays based on mixing bacteria and AgNPs (bacteria+AgNPs). The optimum SERS enhancement of bacteria-AgNPs is obtained under 633-nm laser excitation, and this most likely is due to the plasmonic interaction of aggregated AgNPs. The method allows for an identification and quantification even of single E. coli bacteria. In our perception, this straightforward approach represents a most valuable tool for the detection of E. coli and, conceivably, of other bacteria, and thus has a large potential in environmental monitoring, medical diagnosis, and in food safety and quality control. (author)

Introducing GIS across Levels: Designing for Diversity

Science.gov (United States)

Barros, Joana

2017-01-01

The paper proposes a strategy for designing introductory GIS modules at Birkbeck, University of London. Seven design aspects or elements (content, practical exercises, assessment, pace, mode, level of support, and level of difficulty) for tailoring modules at appropriate levels and for diversity are introduced and their application in Birkbeck's…

Level Design as Model Transformation

NARCIS (Netherlands)

Dormans, Joris

2011-01-01

This paper frames the process of designing a level in a game as a series of model transformations. The transformations correspond to the application of particular design principles, such as the use of locks and keys to transform a linear mission into a branching space. It shows that by using rewrite

Occurrence and distribution of nitrogen-scavenging bacteria in marine environment

OpenAIRE

Sugahara, Isao; Kimura, Toshio; Hayashi, Koichiro

1987-01-01

The occurrence and distribution nitrogen-scavenging bacteria in the water of coastal and oceanic of Japan were studied during the Seisui-Maru cruises from 1986 to 1987. Nitroben-scavenging bacteria in the water usually occurred at the level of 10-104 cfu/ml.This value was almost comparable to that of aerobic heterotrophic bacteria. It seems that nitrogen-scavenging bacteria play an important role in the efficient uptake of low levels of nitrogenous compounds in marine enviroment.

Effects of hot water application after defeathering on the levels of Campylobacter, coliform bacteria, and Escherichia coli on broiler carcasses.

Science.gov (United States)

Berrang, M E; Dickens, J A; Musgrove, M T

2000-11-01

Scalding has been found to lower the levels of Campylobacter on broiler carcasses. However, the numbers recovered from whole-carcass rinse samples increase following defeathering. This study was undertaken to examine the effect of a second scald applied after defeathering on microbial levels recovered from carcass rinses. Four treatments were evaluated: 1) immersion at 60 C for 28 s 30 min after defeathering, 2) immersion at 60 C for 28 s immediately after defeathering, 3) spray at 73 C for 20 s 30 min after defeathering, and 4) spray at 71 C for 20 s immediately after defeathering. As reported earlier, a significant increase in Campylobacter counts per mL whole carcass rinse was noted after carcasses were defeathered. However, when applied 30 min after defeathering, neither the immersion nor the spray second scald treatments lowered the Campylobacter counts. Likewise, neither treatment had any affect on Escherichia coli or coliform bacteria counts, even though total counts were slightly reduced by the treatments. When the second scald treatment immediately followed defeathering, the same trends were observed. Campylobacter counts after the second scald remained at the postpick levels, as did counts for E. coli and coliform bacteria, but total plate counts were slightly reduced. Overall, it would appear that a postscald treatment gentle enough not to alter the carcass appearance or meat quality would not effectively lower Campylobacter, E. coli, or coliform bacteria counts.

Design space pruning through hybrid analysis in system-level design space exploration

NARCIS (Netherlands)

Piscitelli, R.; Pimentel, A.D.

2012-01-01

System-level design space exploration (DSE), which is performed early in the design process, is of eminent importance to the design of complex multi-processor embedded system archi- tectures. During system-level DSE, system parameters like, e.g., the number and type of processors, the type and size

BioNLP Shared Task--The Bacteria Track.

Science.gov (United States)

Bossy, Robert; Jourde, Julien; Manine, Alain-Pierre; Veber, Philippe; Alphonse, Erick; van de Guchte, Maarten; Bessières, Philippe; Nédellec, Claire

2012-06-26

We present the BioNLP 2011 Shared Task Bacteria Track, the first Information Extraction challenge entirely dedicated to bacteria. It includes three tasks that cover different levels of biological knowledge. The Bacteria Gene Renaming supporting task is aimed at extracting gene renaming and gene name synonymy in PubMed abstracts. The Bacteria Gene Interaction is a gene/protein interaction extraction task from individual sentences. The interactions have been categorized into ten different sub-types, thus giving a detailed account of genetic regulations at the molecular level. Finally, the Bacteria Biotopes task focuses on the localization and environment of bacteria mentioned in textbook articles. We describe the process of creation for the three corpora, including document acquisition and manual annotation, as well as the metrics used to evaluate the participants' submissions. Three teams submitted to the Bacteria Gene Renaming task; the best team achieved an F-score of 87%. For the Bacteria Gene Interaction task, the only participant's score had reached a global F-score of 77%, although the system efficiency varies significantly from one sub-type to another. Three teams submitted to the Bacteria Biotopes task with very different approaches; the best team achieved an F-score of 45%. However, the detailed study of the participating systems efficiency reveals the strengths and weaknesses of each participating system. The three tasks of the Bacteria Track offer participants a chance to address a wide range of issues in Information Extraction, including entity recognition, semantic typing and coreference resolution. We found common trends in the most efficient systems: the systematic use of syntactic dependencies and machine learning. Nevertheless, the originality of the Bacteria Biotopes task encouraged the use of interesting novel methods and techniques, such as term compositionality, scopes wider than the sentence.

Experimental design for assessment of electrokinetically enhanced delivery of lactate and bacteria in 1,2-cis-dichloroethylene contaminated limestone

DEFF Research Database (Denmark)

Hyldegaard, Bente Højlund; Nedergaard, L. W.; Ottosen, Lisbeth

2015-01-01

Bacterial dechlorination of chlorinated solvents often causes accumulation of the intermediate cis-DCE. Back diffusion of e.g. cis-DCE, due to the dual porosity of limestone, often limits the remediation efficiency. A remediation scheme capable of establishing contact between contaminant, degrading...... bacteria and electron donor within the low permeable limestone matrix is required. The technology EK-BIO, which combines enhanced reductive dechlorination and electrokinetics (EK), was assessed. This novel technology has not previously been tested in limestone. An experimental set-up was designed to meet...... that fermentative bacteria were distributed by electrophoresis. This study suggests that EK application can establish the essential contact and overcome back diffusion. Thereby, EK-BIO may be superior to advection-based technologies for bioremediation of chlorinated solvent contaminated limestone matrices....

Transfer of antibiotic resistant bacteria from animals to man

DEFF Research Database (Denmark)

Wegener, Henrik Caspar; Aarestrup, Frank Møller; Gerner-Smidt, P.

1999-01-01

for animals either for therapy or for growth promotion. Antibiotic resistance in zoonotic bacteria constitute a public health hazard, primarily through the increased risk of treatment failures. This paper describes the zoonotic bacteria, salmonella, campylobacter, yersinia and enterohaemorrhagic E. coli (EHEC......Antibiotic resistance develops in zoonotic bacteria in response to antibiotics used in food animals. A close association exists between the amounts of antibiotics used and the levels of resistance observed. The classes of antibiotics routinely used for treatment of human infections are also used......). Infections with these agents do not generally require antibiotic therapy, but in some cases antibiotics are essential to obtain a successful cure. The levels and types of resistance observed in zoonotic bacteria in some countries, especially the increasing levels of fluoroquinolone resistance in salmonella...

Bacteria and plutonium in marine environments

International Nuclear Information System (INIS)

Carey, A.E.; Bowen, V.T.

1978-01-01

Microbes are important in geochemical cycling of many elements. Recent reports emphasize biogenous particulates and bacterial exometabolites as controlling oceanic distribution of plutonium. Bacteria perform oxidation/reduction reactions on metals such as mercury, nickel, lead, copper, and cadmium. Redox transformations or uptake of Pu by marine bacteria may well proceed by similar mechanisms. Profiles of water samples and sediment cores were obtained along the continental shelf off Nova Scotia and in the Gulf of St. Lawrence. Profiles of water samples, and sediment cores were obtained. Epifluorescent microscopy was used to view bacteria (from water or sediment) after concentration on membrane filters and staining with acridine orange. Radiochemical analyses measured Pu in sediments and water samples. Studies of 237 Pu uptake used a strain of Leucothrix mucor isolated from a macroalga. Enumeration shows bacteria to range 10 4 to 10 5 cells/ml in seawater or 10 7 to 10 8 cells/gram of sediment. These numbers are related to the levels and distrbution of Pu in the samples. In cultures of L. mucor amended with Pu atom concentrations approximating those present in open ocean environments, bacterial cells concentrated 237 Pu slower and to lower levels than did clay minerals, glass beads, or phytoplankton. These data further clarify the role of marine bacteria in Pu biogeochemistry

Light controlled 3D micromotors powered by bacteria

Science.gov (United States)

Vizsnyiczai, Gaszton; Frangipane, Giacomo; Maggi, Claudio; Saglimbeni, Filippo; Bianchi, Silvio; Di Leonardo, Roberto

2017-01-01

Self-propelled bacteria can be integrated into synthetic micromachines and act as biological propellers. So far, proposed designs suffer from low reproducibility, large noise levels or lack of tunability. Here we demonstrate that fast, reliable and tunable bio-hybrid micromotors can be obtained by the self-assembly of synthetic structures with genetically engineered biological propellers. The synthetic components consist of 3D interconnected structures having a rotating unit that can capture individual bacteria into an array of microchambers so that cells contribute maximally to the applied torque. Bacterial cells are smooth swimmers expressing a light-driven proton pump that allows to optically control their swimming speed. Using a spatial light modulator, we can address individual motors with tunable light intensities allowing the dynamic control of their rotational speeds. Applying a real-time feedback control loop, we can also command a set of micromotors to rotate in unison with a prescribed angular speed. PMID:28656975

Light controlled 3D micromotors powered by bacteria

Science.gov (United States)

Vizsnyiczai, Gaszton; Frangipane, Giacomo; Maggi, Claudio; Saglimbeni, Filippo; Bianchi, Silvio; di Leonardo, Roberto

2017-06-01

Self-propelled bacteria can be integrated into synthetic micromachines and act as biological propellers. So far, proposed designs suffer from low reproducibility, large noise levels or lack of tunability. Here we demonstrate that fast, reliable and tunable bio-hybrid micromotors can be obtained by the self-assembly of synthetic structures with genetically engineered biological propellers. The synthetic components consist of 3D interconnected structures having a rotating unit that can capture individual bacteria into an array of microchambers so that cells contribute maximally to the applied torque. Bacterial cells are smooth swimmers expressing a light-driven proton pump that allows to optically control their swimming speed. Using a spatial light modulator, we can address individual motors with tunable light intensities allowing the dynamic control of their rotational speeds. Applying a real-time feedback control loop, we can also command a set of micromotors to rotate in unison with a prescribed angular speed.

Characterization of mercury bioremediation by transgenic bacteria expressing metallothionein and polyphosphate kinase

Directory of Open Access Journals (Sweden)

Gonzalez-Ruiz Gloriene

2011-08-01

Full Text Available Abstract Background The use of transgenic bacteria has been proposed as a suitable alternative for mercury remediation. Ideally, mercury would be sequestered by metal-scavenging agents inside transgenic bacteria for subsequent retrieval. So far, this approach has produced limited protection and accumulation. We report here the development of a transgenic system that effectively expresses metallothionein (mt-1 and polyphosphate kinase (ppk genes in bacteria in order to provide high mercury resistance and accumulation. Results In this study, bacterial transformation with transcriptional and translational enhanced vectors designed for the expression of metallothionein and polyphosphate kinase provided high transgene transcript levels independent of the gene being expressed. Expression of polyphosphate kinase and metallothionein in transgenic bacteria provided high resistance to mercury, up to 80 μM and 120 μM, respectively. Here we show for the first time that metallothionein can be efficiently expressed in bacteria without being fused to a carrier protein to enhance mercury bioremediation. Cold vapor atomic absorption spectrometry analyzes revealed that the mt-1 transgenic bacteria accumulated up to 100.2 ± 17.6 μM of mercury from media containing 120 μM Hg. The extent of mercury remediation was such that the contaminated media remediated by the mt-1 transgenic bacteria supported the growth of untransformed bacteria. Cell aggregation, precipitation and color changes were visually observed in mt-1 and ppk transgenic bacteria when these cells were grown in high mercury concentrations. Conclusion The transgenic bacterial system described in this study presents a viable technology for mercury bioremediation from liquid matrices because it provides high mercury resistance and accumulation while inhibiting elemental mercury volatilization. This is the first report that shows that metallothionein expression provides mercury resistance and

Thymol treatment of bacteria prior to matrix-assisted laser desorption/ionization time-of-flight mass spectrometric analysis aids in identifying certain bacteria at the subspecies level.

Science.gov (United States)

Holland, Ricky D; Wilkes, Jon G; Cooper, Willie M; Alusta, Pierre; Williams, Anna; Pearce, Bruce; Beaudoin, Michael; Buzatu, Dan

2014-12-15

The identification of bacteria based on mass spectra produced by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) has become routine since its introduction in 1996. The major drawback is that bacterial patterns produced by MALDI are dependent on sample preparation prior to analysis. This results in poor reproducibility in identifying bacterial types and between laboratories. The need for a more broadly applicable and useful sample handling procedure is warranted. Thymol was added to the suspension solvent of bacteria prior to MALDI analysis. The suspension solvent consisted of ethanol, water and TFA. The bacterium was added to the thymol suspension solvent and heated. An aliquot of the bacterial suspension was mixed directly with the matrix solution at a 9:1 ratio, matrix/bacteria solution, respectively. The mixture was then placed on the MALDI plate and allowed to air dry before MALDI analysis. The thymol method improved the quality of spectra and number of peaks when compared to other sample preparation procedures studied. The bacterium-identifying biomarkers assigned to four strains of E. coli were statistically 95% reproducible analyzed on three separate days. The thymol method successfully differentiated between the four E. coli strains. In addition, the thymol procedure could identify nine out of ten S. enterica serovars over a 3-day period and nine S. Typhimurium strains from the other ten serovars 90% of the time over the same period. The thymol method can identify certain bacteria at the sub-species level and yield reproducible results over time. It improves the quality of spectra by increasing the number of peaks when compared to the other sample preparation methods assessed in this study. Published in 2014. This article is a U.S. Government work and is in the public domain in the USA. Published in 2014. This article is a U.S. Government work and is in the public domain in the USA.

Ammonia effect on hydrogenotrophic methanogens and syntrophic acetate oxidizing bacteria

DEFF Research Database (Denmark)

Wang, Han; Fotidis, Ioannis; Angelidaki, Irini

Substrates that contain high ammonia levels can cause inhibition on anaerobic digestion process and unstable biogas production. The aim of the current study was to assess the effects of different ammonia levels on pure strains of (syntrophic acetate oxidizing) SAO bacteria and hydrogenotrophic...... methanogens. Two pure strains of hydrogenotrophic methanogens (i.e: Methanoculleus bourgensis and Methanoculleus thermophiles) and two pure strains of SAO bacteria (i.e: Tepidanaerobacter acetatoxydans and Thermacetogenium phaeum) were inoculated under four different ammonia (0.26, 3, 5 and 7g NH4+-N......, the total incubation periods of hydrogenotrophic methanogens were significantly shorter compared to the SAO bacteria incubation periods. Thus, it seems that hydrogenotrophic methanogens could be equally, if not more, tolerant to high ammonia levels compared to SAO bacteria....

Re-sensitizing drug-resistant bacteria to antibiotics by designing Antisense Therapeutics

Science.gov (United States)

Courtney, Colleen; Chatterjee, Anushree

2014-03-01

``Super-bugs'' or ``multi-drug resistant organisms'' are a serious international health problem, with devastating consequences to patient health care. The Center for Disease Control has identified antibiotic resistance as one of the world's most pressing public health problems as a significant fraction of bacterial infections contracted are drug resistant. Typically, antibiotic resistance is encoded by ``resistance-genes'' which express proteins that carryout the resistance causing functions inside the bacterium. We present a RNA based therapeutic strategy for designing antimicrobials capable of re-sensitizing resistant bacteria to antibiotics by targeting labile regions of messenger RNAs encoding for resistance-causing proteins. We perform in silico RNA secondary structure modeling to identify labile target regions in an mRNA of interest. A synthetic biology approach is then used to administer antisense nucleic acids to our model system of ampicillin resistant Escherichia coli. Our results show a prolonged lag phase and decrease in viability of drug-resistant E. colitreated with antisense molecules. The antisense strategy can be applied to alter expression of other genes in antibiotic resistance pathways or other pathways of interest.

What Bacteria Are Living in My Food?: An Open-Ended Practical Series Involving Identification of Unknown Foodborne Bacteria Using Molecular Techniques

Science.gov (United States)

Prasad, Prascilla; Turner, Mark S.

2011-01-01

This open-ended practical series titled "Molecular Identification of Unknown Food Bacteria" which extended over a 6-week period was designed with the aims of giving students an opportunity to gain an understanding of naturally occurring food bacteria and skills in contemporary molecular methods using real food samples. The students first isolated…

Effects of Ethanolic Ferolagu angulata Extract on Pathogenic Gastrointestinal Bacteria and Probiotic Bacteria in Skimmed Milk Medium

Directory of Open Access Journals (Sweden)

Reza Naghiha

2016-12-01

Full Text Available Background:    Due to excessive consumption of synthetic drugs, drug resistance rate of pathogenic bacteria is increasing and there is an ever-increasing need to find new safe compounds to tackle this problem. This study was conducted to investigate the consequences of chavill extract on the growth and viability of gastrointestinal pathogenic bacterium and probiotics bacteria. Methods:    The experiment contained three levels of the chavill extract concentrations (0, 1 and 3% which were added to the milk free fat in accompany with three probiotic bacteria (Lactobacillus acidophilus, Lactobacillus casei and lactobacillus plantaram and a pathogenic gastrointestinal bacterium (Salmonella typhimurium. Bacterial inoculums (1×107 CFU/ml with different concentrations of chavill extract were added to skimmed milk medium and bacteria growth were enumerated. Results:  The concentration of 1% chavill extract significantly increased the total count of probiotic bacteria compared to the control group, while the number of pathogenic bacteria was decreased. At 3% chavill extract the growth of Lactobacillus acidophilus and Lactobacillus plantaram were increased. On the other hand, it prevented the growth of Salmonella typhimurium Conclusion:   Chavill extracts would play as an alternative to antibiotics in pharmacological studies to decreases harmful bacteria and increase probiotic bacteria.

Thermophilic Sulfate-Reducing Bacteria in Cold Marine Sediment

DEFF Research Database (Denmark)

ISAKSEN, MF; BAK, F.; JØRGENSEN, BB

1994-01-01

sulfate-reducing bacteria was detected. Time course experiments showed constant sulfate reduction rates at 4 degrees C and 30 degrees C, whereas the activity at 60 degrees C increased exponentially after a lag period of one day. Thermophilic, endospore-forming sulfate-reducing bacteria, designated strain...... C to search for presence of psychrophilic, mesophilic and thermophilic sulfate-reducing bacteria. Detectable activity was initially only in the mesophilic range, but after a lag phase sulfate reduction by thermophilic sulfate-reducing bacteria were observed. No distinct activity of psychrophilic...... P60, were isolated and characterized as Desulfotomaculum kuznetsovii. The temperature response of growth and respiration of strain P60 agreed well with the measured sulfate reduction at 50 degrees-70 degrees C. Bacteria similar to strain P60 could thus be responsible for the measured thermophilic...

Thermophilic Sulfate-Reducing Bacteria in Cold Marine Sediment

DEFF Research Database (Denmark)

ISAKSEN, MF; BAK, F.; JØRGENSEN, BB

1994-01-01

C to search for presence of psychrophilic, mesophilic and thermophilic sulfate-reducing bacteria. Detectable activity was initially only in the mesophilic range, but after a lag phase sulfate reduction by thermophilic sulfate-reducing bacteria were observed. No distinct activity of psychrophilic...... sulfate-reducing bacteria was detected. Time course experiments showed constant sulfate reduction rates at 4 degrees C and 30 degrees C, whereas the activity at 60 degrees C increased exponentially after a lag period of one day. Thermophilic, endospore-forming sulfate-reducing bacteria, designated strain...... P60, were isolated and characterized as Desulfotomaculum kuznetsovii. The temperature response of growth and respiration of strain P60 agreed well with the measured sulfate reduction at 50 degrees-70 degrees C. Bacteria similar to strain P60 could thus be responsible for the measured thermophilic...

Design of a surface-scanning coil detector for direct bacteria detection on food surfaces using a magnetoelastic biosensor

Science.gov (United States)

Chai, Yating; Wikle, Howard C.; Wang, Zhenyu; Horikawa, Shin; Best, Steve; Cheng, Zhongyang; Dyer, Dave F.; Chin, Bryan A.

2013-09-01

The real-time, in-situ bacteria detection on food surfaces was achieved by using a magnetoelastic biosensor combined with a surface-scanning coil detector. This paper focuses on the coil design for signal optimization. The coil was used to excite the sensor's vibration and detect its resonant frequency signal. The vibrating sensor creates a magnetic flux change around the coil, which then produces a mutual inductance. In order to enhance the signal amplitude, a theory of the sensor's mutual inductance with the measurement coil is proposed. Both theoretical calculations and experimental data showed that the working length of the coil has a significant effect on the signal amplitude. For a 1 mm-long sensor, a coil with a working length of 1.3 mm showed the best signal amplitude. The real-time detection of Salmonella bacteria on a fresh food surface was demonstrated using this new technology.

Rationalizing the permeation of polar antibiotics into Gram-negative bacteria

International Nuclear Information System (INIS)

Scorciapino, Mariano Andrea; Acosta-Gutierrez, Silvia; Benkerrou, Dehbia; D’Agostino, Tommaso; Malloci, Giuliano; Samanta, Susruta; Bodrenko, Igor; Ceccarelli, Matteo

2017-01-01

The increasing level of antibiotic resistance in Gram-negative bacteria, together with the lack of new potential drug scaffolds in the pipeline, make the problem of infectious diseases a global challenge for modern medicine. The main reason that Gram-negative bacteria are particularly challenging is the presence of an outer cell-protecting membrane, which is not present in Gram-positive species. Such an asymmetric bilayer is a highly effective barrier for polar molecules. Several protein systems are expressed in the outer membrane to control the internal concentration of both nutrients and noxious species, in particular: (i) water-filled channels that modulate the permeation of polar molecules and ions according to concentration gradients, and (ii) efflux pumps to actively expel toxic compounds. Thus, besides expressing specific enzymes for drugs degradation, Gram-negative bacteria can also resist by modulating the influx and efflux of antibiotics, keeping the internal concentration low. However, there are no direct and robust experimental methods capable of measuring the permeability of small molecules, thus severely limiting our knowledge of the molecular mechanisms that ultimately control the permeation of antibiotics through the outer membrane. This is the innovation gap to be filled for Gram-negative bacteria. This review is focused on the permeation of small molecules through porins, considered the main path for the entry of polar antibiotics into Gram-negative bacteria. A fundamental understanding of how these proteins are able to filter small molecules is a prerequisite to design/optimize antibacterials with improved permeation. The level of sophistication of modern molecular modeling algorithms and the advances in new computer hardware has made the simulation of such complex processes possible at the molecular level. In this work we aim to share our experience and perspectives in the context of a multidisciplinary extended collaboration within the IMI

Rationalizing the permeation of polar antibiotics into Gram-negative bacteria

Science.gov (United States)

Scorciapino, Mariano Andrea; Acosta-Gutierrez, Silvia; Benkerrou, Dehbia; D'Agostino, Tommaso; Malloci, Giuliano; Samanta, Susruta; Bodrenko, Igor; Ceccarelli, Matteo

2017-03-01

The increasing level of antibiotic resistance in Gram-negative bacteria, together with the lack of new potential drug scaffolds in the pipeline, make the problem of infectious diseases a global challenge for modern medicine. The main reason that Gram-negative bacteria are particularly challenging is the presence of an outer cell-protecting membrane, which is not present in Gram-positive species. Such an asymmetric bilayer is a highly effective barrier for polar molecules. Several protein systems are expressed in the outer membrane to control the internal concentration of both nutrients and noxious species, in particular: (i) water-filled channels that modulate the permeation of polar molecules and ions according to concentration gradients, and (ii) efflux pumps to actively expel toxic compounds. Thus, besides expressing specific enzymes for drugs degradation, Gram-negative bacteria can also resist by modulating the influx and efflux of antibiotics, keeping the internal concentration low. However, there are no direct and robust experimental methods capable of measuring the permeability of small molecules, thus severely limiting our knowledge of the molecular mechanisms that ultimately control the permeation of antibiotics through the outer membrane. This is the innovation gap to be filled for Gram-negative bacteria. This review is focused on the permeation of small molecules through porins, considered the main path for the entry of polar antibiotics into Gram-negative bacteria. A fundamental understanding of how these proteins are able to filter small molecules is a prerequisite to design/optimize antibacterials with improved permeation. The level of sophistication of modern molecular modeling algorithms and the advances in new computer hardware has made the simulation of such complex processes possible at the molecular level. In this work we aim to share our experience and perspectives in the context of a multidisciplinary extended collaboration within the IMI

Anaerobic bacteria

Science.gov (United States)

Anaerobic bacteria are bacteria that do not live or grow when oxygen is present. In humans, these bacteria ... Brook I. Diseases caused by non-spore-forming anaerobic bacteria. In: Goldman L, Schafer AI, eds. Goldman-Cecil ...

3D printing of bacteria into functional complex materials.

Science.gov (United States)

Schaffner, Manuel; Rühs, Patrick A; Coulter, Fergal; Kilcher, Samuel; Studart, André R

2017-12-01

Despite recent advances to control the spatial composition and dynamic functionalities of bacteria embedded in materials, bacterial localization into complex three-dimensional (3D) geometries remains a major challenge. We demonstrate a 3D printing approach to create bacteria-derived functional materials by combining the natural diverse metabolism of bacteria with the shape design freedom of additive manufacturing. To achieve this, we embedded bacteria in a biocompatible and functionalized 3D printing ink and printed two types of "living materials" capable of degrading pollutants and of producing medically relevant bacterial cellulose. With this versatile bacteria-printing platform, complex materials displaying spatially specific compositions, geometry, and properties not accessed by standard technologies can be assembled from bottom up for new biotechnological and biomedical applications.

Relationship of periodontal infection to serum antibody levels to periodontopathic bacteria and inflammatory markers in periodontitis patients with coronary heart disease

Science.gov (United States)

Yamazaki, K; Honda, T; Domon, H; Okui, T; Kajita, K; Amanuma, R; Kudoh, C; Takashiba, S; Kokeguchi, S; Nishimura, F; Kodama, M; Aizawa, Y; Oda, H

2007-01-01

Several reports have demonstrated a possible association of periodontal infections with coronary heart disease (CHD) by elevated antibody titre to periodontopathic bacteria in CHD patients compared with non-diseased controls. Although each periodontopathic bacterium may vary in virulence for periodontitis and atherosclerosis, antibody response to multiple bacteria in CHD patients has not been understood fully. Therefore, serum levels of antibody to 12 periodontopathic bacteria together with other atherosclerotic risk markers were compared among 51 patients with CHD, 55 patients with moderate to severe chronic periodontitis and 37 healthy individuals. The antibody response was the most prevalent for Porphyromonas gingivalis, a major causative organism, in CHD as well as periodontitis patients. However, antibody positivity was different between CHD and periodontitis if the response was analysed for two different strains of P. gingivalis, namely FDC381 and Su63. While periodontitis patients were positive for both P. gingivalis FDC381 and Su63, a high frequency of antibody positivity for P. gingivalis Su63 but not for FDC381 was observed in CHD patients. The results indicate that the presence of particular periodontopathic bacteria with high virulence may affect atherogenesis. Identifying the virulence factors of P. gingivalis Su63 may gain insight into the new therapeutic modality for infection-induced deterioration of atherosclerosis. PMID:17645769

Variability of cutaneous and nasal population levels between patients colonized and infected by multidrug-resistant bacteria in two Brazilian intensive care units.

Science.gov (United States)

Damaceno, Quésia; Nicoli, Jacques R; Oliveira, Adriana

2015-01-01

To compare cutaneous and nasal population levels between patients colonized and infected by multidrug-resistant organisms in two intensive care units. A prospective cohort study was performed in adult intensive care units of two hospitals in Belo Horizonte, Brazil (April 2012 to February 2013). Clinical and demographic data were first collected by reviewing patients' charts. Then, samples collected with nasal, groin, and perineum swabs were cultivated in selective media for 48 h at 37°C. After isolation, determination of antimicrobial susceptibility and biochemical identification were performed. A total of 53 cases of colonization were observed by the following bacteria in decreasing frequencies: imipenem-resistant Acinetobacter baumannii (50.9%), vancomycin-resistant Enterococcus faecalis (43.4%), extended-spectrum beta-lactamase-producing Klebsiella pneumoniae (37.7%), imipenem-resistant Pseudomonas aeruginosa (32.1%), oxacillin-resistant Staphylococcus aureus (7.5%), and imipenem-resistant Klebsiella pneumoniae (5.7%). Among these colonization cases, 26 (49.0%) were followed by infection with bacteria phenotypically similar to those of the colonization. A relation between high population levels of colonization by most of the multidrug-resistant organisms at anatomical sites and a subsequent infection was observed. After colonization/infection, bacterial population levels decreased progressively and spontaneously until disappearance by day 45 in all the anatomical sites and for all the multidrug-resistant organisms. There was a correlation between high population levels of colonization by multidrug-resistant organisms at anatomical sites and a subsequent infection. Reduction in multidrug-resistant organism populations after colonization at anatomical sites could be a preventive measure to reduce evolution to infection as well as transmission of these bacteria between patients in intensive care unit.

Temporal variability of the bioaerosol background at a subway station: concentration level, size distribution, and diversity of airborne bacteria.

Science.gov (United States)

Dybwad, Marius; Skogan, Gunnar; Blatny, Janet Martha

2014-01-01

Naturally occurring bioaerosol environments may present a challenge to biological detection-identification-monitoring (BIODIM) systems aiming at rapid and reliable warning of bioterrorism incidents. One way to improve the operational performance of BIODIM systems is to increase our understanding of relevant bioaerosol backgrounds. Subway stations are enclosed public environments which may be regarded as potential bioterrorism targets. This study provides novel information concerning the temporal variability of the concentration level, size distribution, and diversity of airborne bacteria in a Norwegian subway station. Three different air samplers were used during a 72-h sampling campaign in February 2011. The results suggested that the airborne bacterial environment was stable between days and seasons, while the intraday variability was found to be substantial, although often following a consistent diurnal pattern. The bacterial levels ranged from not detected to 10(3) CFU m(-3) and generally showed increased levels during the daytime compared to the nighttime levels, as well as during rush hours compared to non-rush hours. The airborne bacterial levels showed rapid temporal variation (up to 270-fold) on some occasions, both consistent and inconsistent with the diurnal profile. Airborne bacterium-containing particles were distributed between different sizes for particles of >1.1 μm, although ∼50% were between 1.1 and 3.3 μm. Anthropogenic activities (mainly passengers) were demonstrated as major sources of airborne bacteria and predominantly contributed 1.1- to 3.3-μm bacterium-containing particles. Our findings contribute to the development of realistic testing and evaluation schemes for BIODIM equipment by providing information that may be used to simulate operational bioaerosol backgrounds during controlled aerosol chamber-based challenge tests with biological threat agents.

Temporal Variability of the Bioaerosol Background at a Subway Station: Concentration Level, Size Distribution, and Diversity of Airborne Bacteria

Science.gov (United States)

Dybwad, Marius; Skogan, Gunnar

2014-01-01

Naturally occurring bioaerosol environments may present a challenge to biological detection-identification-monitoring (BIODIM) systems aiming at rapid and reliable warning of bioterrorism incidents. One way to improve the operational performance of BIODIM systems is to increase our understanding of relevant bioaerosol backgrounds. Subway stations are enclosed public environments which may be regarded as potential bioterrorism targets. This study provides novel information concerning the temporal variability of the concentration level, size distribution, and diversity of airborne bacteria in a Norwegian subway station. Three different air samplers were used during a 72-h sampling campaign in February 2011. The results suggested that the airborne bacterial environment was stable between days and seasons, while the intraday variability was found to be substantial, although often following a consistent diurnal pattern. The bacterial levels ranged from not detected to 103 CFU m−3 and generally showed increased levels during the daytime compared to the nighttime levels, as well as during rush hours compared to non-rush hours. The airborne bacterial levels showed rapid temporal variation (up to 270-fold) on some occasions, both consistent and inconsistent with the diurnal profile. Airborne bacterium-containing particles were distributed between different sizes for particles of >1.1 μm, although ∼50% were between 1.1 and 3.3 μm. Anthropogenic activities (mainly passengers) were demonstrated as major sources of airborne bacteria and predominantly contributed 1.1- to 3.3-μm bacterium-containing particles. Our findings contribute to the development of realistic testing and evaluation schemes for BIODIM equipment by providing information that may be used to simulate operational bioaerosol backgrounds during controlled aerosol chamber-based challenge tests with biological threat agents. PMID:24162566

Automated radiometric detection of bacteria

International Nuclear Information System (INIS)

Waters, J.R.

1974-01-01

A new radiometric method called BACTEC, used for the detection of bacteria in cultures or in supposedly sterile samples, was discussed from the standpoint of methodology, both automated and semi-automated. Some of the results obtained so far were reported and some future applications and development possibilities were described. In this new method, the test sample is incubated in a sealed vial with a liquid culture medium containing a 14 C-labeled substrate. If bacteria are present, they break down the substrate, producing 14 CO 2 which is periodically extracted from the vial as a gas and is tested for radioactivity. If this gaseous radioactivity exceeds a threshold level, it is evidence of bacterial presence and growth in the test vial. The first application was for the detection of bacteria in the blood cultures of hospital patients. Data were presented showing typical results. Also discussed were future applications, such as rapid screening for bacteria in urine industrial sterility testing and the disposal of used 14 C substrates. (Mukohata, S.)

Catalase epitopes vaccine design for Helicobacter pylori : A ...

African Journals Online (AJOL)

Catalase, an important enzyme in the virulence of H. pylori, could be a suitable candidate for vaccine design because it is highly conserved, which is important for the survival of H. pylori; it is expressed in high level and it is exposed on the surface of the bacteria. In this study, we designed epitope-based vaccine for catalase ...

Phg1/TM9 proteins control intracellular killing of bacteria by determining cellular levels of the Kil1 sulfotransferase in Dictyostelium.

Directory of Open Access Journals (Sweden)

Marion Le Coadic

Full Text Available Dictyostelium discoideum has largely been used to study phagocytosis and intracellular killing of bacteria. Previous studies have shown that Phg1A, Kil1 and Kil2 proteins are necessary for efficient intracellular killing of Klebsiella bacteria. Here we show that in phg1a KO cells, cellular levels of lysosomal glycosidases and lysozyme are decreased, and lysosomal pH is increased. Surprisingly, overexpression of Kil1 restores efficient killing in phg1a KO cells without correcting these lysosomal anomalies. Conversely, kil1 KO cells are defective for killing, but their enzymatic content and lysosomal pH are indistinguishable from WT cells. The killing defect of phg1a KO cells can be accounted for by the observation that in these cells the stability and the cellular amount of Kil1 are markedly reduced. Since Kil1 is the only sulfotransferase characterized in Dictyostelium, an (unidentified sulfated factor, defective in both phg1a and kil1 KO cells, may play a key role in intracellular killing of Klebsiella bacteria. In addition, Phg1B plays a redundant role with Phg1A in controlling cellular amounts of Kil1 and intracellular killing. Finally, cellular levels of Kil1 are unaffected in kil2 KO cells, and Kil1 overexpression does not correct the killing defect of kil2 KO cells, suggesting that Kil2 plays a distinct role in intracellular killing.

Toxicity of tetracyclines and tetracycline degradation products to environmentally relevant bacteria, including selected tetracycline-resistant bacteria

DEFF Research Database (Denmark)

Halling-Sørensen, B.; Sengeløv, G.; Tjørnelund, J.

2002-01-01

Tetracyclines used in veterinary therapy invariably will find their way as parent compound and degradation products to the agricultural field. Major degradation products formed due to the limited stability of parent tetracyclines (tetracycline, chlortetracycline, and oxytetracycline) in aqueous...... at the same concentration level as tetracycline, chlortetracycline, and oxytetracycline on both the sludge and the tetracycline-sensitive soil bacteria. Further, both 5a,6-anhydrotetracychne and 5a,6-anhydrochlortetracycline had potency on tetracycline-resistant bacteria supporting a mode of action different...

Magnetosome chain superstructure in uncultured magnetotactic bacteria

International Nuclear Information System (INIS)

Abraçado, Leida G; Farina, Marcos; Abreu, Fernanda; Keim, Carolina N; Lins, Ulysses; Campos, Andrea P C

2010-01-01

Magnetotactic bacteria produce magnetosomes, which are magnetic particles enveloped by biological membranes, in a highly controlled mineralization process. Magnetosomes are used to navigate in magnetic fields by a phenomenon called magnetotaxis. Two levels of organization and control are recognized in magnetosomes. First, magnetotactic bacteria create a spatially distinct environment within vesicles defined by their membranes. In the vesicles, the bacteria control the size, composition and purity of the mineral content of the magnetic particles. Unique crystal morphologies are produced in magnetosomes as a consequence of this bacterial control. Second, magnetotactic bacteria organize the magnetosomes in chains within the cell body. It has been shown in a particular case that the chains are positioned within the cell body in specific locations defined by filamentous cytoskeleton elements. Here, we describe an additional level of organization of the magnetosome chains in uncultured magnetotactic cocci found in marine and freshwater sediments. Electron microscopy analysis of the magnetosome chains using a goniometer showed that the magnetic crystals in both types of bacteria are not oriented at random along the crystal chain. Instead, the magnetosomes have specific orientations relative to the other magnetosomes in the chain. Each crystal is rotated either 60°, 180° or 300° relative to their neighbors along the chain axis, causing the overlapping of the (1 1 1) and (1-bar 1-bar 1-bar) capping faces of neighboring crystals. We suggest that genetic determinants that are not present or active in bacteria with magnetosomes randomly rotated within a chain must be present in bacteria that organize magnetosomes so precisely. This particular organization may also be used as an indicative biosignature of magnetosomes in the study of magnetofossils in the cases where this symmetry is observed

Extracellular deoxyribonuclease production by periodontal bacteria.

Science.gov (United States)

Palmer, L J; Chapple, I L C; Wright, H J; Roberts, A; Cooper, P R

2012-08-01

Whilst certain bacteria have long been known to secrete extracellular deoxyribonuclease (DNase), the purpose in microbial physiology was unclear. Recently, however, this enzyme has been demonstrated to confer enhanced virulence, enabling bacteria to evade the host's immune defence of extruded DNA/chromatin filaments, termed neutrophil extracellular traps (NETs). As NETs have recently been identified in infected periodontal tissue, the aim of this study was to screen periodontal bacteria for extracellular DNase activity. To determine whether DNase activity was membrane bound or secreted, 34 periodontal bacteria were cultured in broth and on agar plates. Pelleted bacteria and supernatants from broth cultures were analysed for their ability to degrade DNA, with relative activity levels determined using an agarose gel electrophoresis assay. Following culture on DNA-supplemented agar, expression was determined by the presence of a zone of hydrolysis and DNase activity related to colony size. Twenty-seven bacteria, including red and orange complex members Porphyromonas gingivalis, Tannerella forsythia, Fusobacterium nucleatum, Parvimonas micra, Prevotella intermedia, Streptococcus constellatus, Campylobacter rectus and Prevotella nigrescens, were observed to express extracellular DNase activity. Differences in DNase activity were noted, however, when bacteria were assayed in different culture states. Analysis of the activity of secreted DNase from bacterial broth cultures confirmed their ability to degrade NETs. The present study demonstrates, for the first time, that DNase activity is a relatively common property of bacteria associated with advanced periodontal disease. Further work is required to determine the importance of this bacterial DNase activity in the pathogenesis of periodontitis. © 2011 John Wiley & Sons A/S.

The effects of low-level ionizing radiation and copper exposure on the incidence of antibiotic resistance in lentic biofilm bacteria.

Science.gov (United States)

McArthur, J Vaun; Dicks, Christian A; Bryan, A Lawrence; Tuckfield, R Cary

2017-09-01

Environmental reservoirs of antibiotic resistant bacteria are poorly understood. Understanding how the environment selects for resistance traits in the absence of antibiotics is critical in developing strategies to mitigate this growing menace. Indirect or co-selection of resistance by environmental pollution has been shown to increase antibiotic resistance. However no attention has been given to the effects of low-level ionizing radiation or the interactions between radiation and heavy metals on the maintenance or selection for antibiotic resistance (AR) traits. Here we explore the effect of radiation and copper on antibiotic resistance. Bacteria were collected from biofilms in two ponds - one impacted by low-level radiocesium and the other an abandoned farm pond. Through laboratory controlled experiments we examined the effects of increasing concentrations of copper on the incidence of antibiotic resistance. Differences were detected in the resistance profiles of the controls from each pond. Low levels (0.01 mM) of copper sulfate increased resistance but 0.5 mM concentrations of copper sulfate depressed the AR response in both ponds. A similar pattern was observed for levels of multiple antibiotic resistance per isolate. The first principal component response of isolate exposure to multiple antibiotics showed significant differences among the six isolate treatment combinations. These differences were clearly visualized through a discriminant function analysis, which showed distinct antibiotic resistance response patterns based on the six treatment groups. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fungi and bacteria inventory on soybean (Glycine max (L.) merill) planting media applied by local microorganisms

Science.gov (United States)

Akhsan, Ni'matuljannah; Vionita

2017-02-01

An experiment aimed to determine the effect of application of several types of local microorganisms (MOL) and the number of doses to the development of fungi and bacteria on soybean planting media, have been conducted in Samarinda for 3 (three) months. Factorial experiment arranged in a completely randomized design and repeated three times, was used in this experiment. The first factor was the type of MOL consisted of cow dung (m1), snails (m2), banana peel (m3) and bamboo roots (m4), and the second factor was the dose MOL zero mL (d0), 100 mL (d1), 200 mL (d2), 300 mL (d3), 400 mL (d4) analyzed with Anova and Least Significance Difference (LSD) at 5%. Fungi and bacteria contained in the local microorganisms (cow dung, snails, banana peel and bamboo root) are: fungus Aspergillus sp, Penicillium sp., Trichoderma sp., cellulotic and lignolitic bacteria. An increase in the type and amount of fungus is happened for some genus. The dominant bacteria in the planting medium is a gram-negative bacteria. Cow dung seemed the best source at the dosages level of 400 ml.

Design Life Level: Quantifying risk in a changing climate

Science.gov (United States)

Rootzén, Holger; Katz, Richard W.

2013-09-01

In the past, the concepts of return levels and return periods have been standard and important tools for engineering design. However, these concepts are based on the assumption of a stationary climate and do not apply to a changing climate, whether local or global. In this paper, we propose a refined concept, Design Life Level, which quantifies risk in a nonstationary climate and can serve as the basis for communication. In current practice, typical hydrologic risk management focuses on a standard (e.g., in terms of a high quantile corresponding to the specified probability of failure for a single year). Nevertheless, the basic information needed for engineering design should consist of (i) the design life period (e.g., the next 50 years, say 2015-2064); and (ii) the probability (e.g., 5% chance) of a hazardous event (typically, in the form of the hydrologic variable exceeding a high level) occurring during the design life period. Capturing both of these design characteristics, the Design Life Level is defined as an upper quantile (e.g., 5%) of the distribution of the maximum value of the hydrologic variable (e.g., water level) over the design life period. We relate this concept and variants of it to existing literature and illustrate how they, and some useful complementary plots, may be computed and used. One practically important consideration concerns quantifying the statistical uncertainty in estimating a high quantile under nonstationarity.

Characterizing speed-independence of high-level designs

DEFF Research Database (Denmark)

Kishinevsky, Michael; Staunstrup, Jørgen

1994-01-01

This paper characterizes the speed-independence of high-level designs. The characterization is a condition on the design description ensuring that the behavior of the design is independent of the speeds of its components. The behavior of a circuit is modeled as a transition system, that allows data...... types, and internal as well as external non-determinism. This makes it possible to verify the speed-independence of a design without providing an explicit realization of the environment. The verification can be done mechanically. A number of experimental designs have been verified including a speed-independent...

Bacteria in atmospheric waters: Detection, characteristics and implications

Science.gov (United States)

Hu, Wei; Niu, Hongya; Murata, Kotaro; Wu, Zhijun; Hu, Min; Kojima, Tomoko; Zhang, Daizhou

2018-04-01

In this review paper, we synthesize the current knowledges about bacteria in atmospheric waters, e.g., cloud, fog, rain, and snow, most of which were obtained very recently. First, we briefly describe the importance of bacteria in atmospheric waters, i.e., the essentiality of studying bacteria in atmospheric waters in understanding aerosol-cloud-precipitation-climate interactions in the Earth system. Next, approaches to collect atmospheric water samples for the detection of bacteria and methods to identify the bacteria are summarized and compared. Then the available data on the abundance, viability and community composition of bacteria in atmospheric waters are summarized. The average bacterial concentration in cloud water was usually on the order 104-105 cells mL-1, while that in precipitation on the order 103-104 cells mL-1. Most of the bacteria were viable or metabolically active. Their community composition was highly diverse and differed at various sites. Factors potentially influencing the bacteria, e.g., air pollution levels and sources, meteorological conditions, seasonal effect, and physicochemical properties of atmospheric waters, are described. After that, the implications of bacteria present in atmospheric waters, including their effect on nucleation in clouds, atmospheric chemistry, ecosystems and public health, are briefly discussed. Finally, based on the current knowledges on bacteria in atmospheric waters, which in fact remains largely unknown, we give perspectives that should be paid attention to in future studies.

Antibiotic resistance shaping multi-level population biology of bacteria.

Science.gov (United States)

Baquero, Fernando; Tedim, Ana P; Coque, Teresa M

2013-01-01

Antibiotics have natural functions, mostly involving cell-to-cell signaling networks. The anthropogenic production of antibiotics, and its release in the microbiosphere results in a disturbance of these networks, antibiotic resistance tending to preserve its integrity. The cost of such adaptation is the emergence and dissemination of antibiotic resistance genes, and of all genetic and cellular vehicles in which these genes are located. Selection of the combinations of the different evolutionary units (genes, integrons, transposons, plasmids, cells, communities and microbiomes, hosts) is highly asymmetrical. Each unit of selection is a self-interested entity, exploiting the higher hierarchical unit for its own benefit, but in doing so the higher hierarchical unit might acquire critical traits for its spread because of the exploitation of the lower hierarchical unit. This interactive trade-off shapes the population biology of antibiotic resistance, a composed-complex array of the independent "population biologies." Antibiotics modify the abundance and the interactive field of each of these units. Antibiotics increase the number and evolvability of "clinical" antibiotic resistance genes, but probably also many other genes with different primary functions but with a resistance phenotype present in the environmental resistome. Antibiotics influence the abundance, modularity, and spread of integrons, transposons, and plasmids, mostly acting on structures present before the antibiotic era. Antibiotics enrich particular bacterial lineages and clones and contribute to local clonalization processes. Antibiotics amplify particular genetic exchange communities sharing antibiotic resistance genes and platforms within microbiomes. In particular human or animal hosts, the microbiomic composition might facilitate the interactions between evolutionary units involved in antibiotic resistance. The understanding of antibiotic resistance implies expanding our knowledge on multi-level

Diversity, abundance, and possible sources of fecal bacteria in the Yangtze River.

Science.gov (United States)

Sun, Haohao; He, Xiwei; Ye, Lin; Zhang, Xu-Xiang; Wu, Bing; Ren, Hongqiang

2017-03-01

The fecal bacteria in natural waters may pose serious risks on human health. Although many source tracking methods have been developed and used to determine the possible sources of the fecal pollution, little is known about the overall diversity and abundance of fecal bacterial community in natural waters. In this study, a method based on fecal bacterial sequence library was introduced to evaluate the fecal bacterial profile in the Yangtze River (Nanjing section). Our results suggested that the Yangtze River water harbors diverse fecal bacteria. Fifty-eight fecal operational taxonomic units (97% identity level) were detected in the Yangtze River water samples and the relative abundance of fecal bacteria in these samples ranged from 0.1 to 8%. It was also found that the relative abundances of the fecal bacteria in locations near to the downstream of wastewater treatment plants were obviously higher than those in other locations. However, the high abundance of fecal bacteria could decrease to the normal level in 2~4 km in the river due to degradation or dilution, and the overall fecal bacteria level changed little when the Yangtze River flew through the Nanjing City. Moreover, the fecal bacteria in the Yangtze River water were found to be highly associated (Spearman rho = 0.804, P Yangtze River and advance our understandings of the fecal bacteria community in the natural waters.

System-Level Design Methodologies for Networked Multiprocessor Systems-on-Chip

DEFF Research Database (Denmark)

Virk, Kashif Munir

2008-01-01

is the first such attempt in the published literature. The second part of the thesis deals with the issues related to the development of system-level design methodologies for networked multiprocessor systems-on-chip at various levels of design abstraction with special focus on the modeling and design...... at the system-level. The multiprocessor modeling framework is then extended to include models of networked multiprocessor systems-on-chip which is then employed to model wireless sensor networks both at the sensor node level as well as the wireless network level. In the third and the final part, the thesis...... to the transaction-level model. The thesis, as a whole makes contributions by describing a design methodology for networked multiprocessor embedded systems at three layers of abstraction from system-level through transaction-level to the cycle accurate level as well as demonstrating it practically by implementing...

Coupling of heterotrophic bacteria to phytoplankton bloom development at different pCO2 levels: a mesocosm study

Directory of Open Access Journals (Sweden)

R. Thyrhaug

2008-07-01

Full Text Available The predicted rise in anthropogenic CO2 emissions will increase CO2 concentrations and decrease seawater pH in the upper ocean. Recent studies have revealed effects of pCO2 induced changes in seawater chemistry on a variety of marine life forms, in particular calcifying organisms. To test whether the predicted increase in pCO2 will directly or indirectly (via changes in phytoplankton dynamics affect abundance, activities, and community composition of heterotrophic bacteria during phytoplankton bloom development, we have aerated mesocosms with CO2 to obtain triplicates with three different partial pressures of CO2 (pCO2: 350 μatm (1×CO2, 700 μatm (2×CO2 and 1050 μatm (3×CO2. The development of a phytoplankton bloom was initiated by the addition of nitrate and phosphate. In accordance to an elevated carbon to nitrogen drawdown at increasing pCO2, bacterial production (BPP of free-living and attached bacteria as well as cell-specific BPP (csBPP of attached bacteria were related to the C:N ratio of suspended matter. These relationships significantly differed among treatments. However, bacterial abundance and activities were not statistically different among treatments. Solely community structure of free-living bacteria changed with pCO2 whereas that of attached bacteria seemed to be independent of pCO2 but tightly coupled to phytoplankton bloom development. Our findings imply that changes in pCO2, although reflected by changes in community structure of free-living bacteria, do not directly affect bacterial activity. Furthermore, bacterial activity and dynamics of heterotrophic bacteria, especially of attached bacteria, were tightly correlated to phytoplankton development and, hence, may also potentially depend on changes in pCO2.

Chemical signaling between plants and plant-pathogenic bacteria.

Science.gov (United States)

Venturi, Vittorio; Fuqua, Clay

2013-01-01

Studies of chemical signaling between plants and bacteria in the past have been largely confined to two models: the rhizobial-legume symbiotic association and pathogenesis between agrobacteria and their host plants. Recent studies are beginning to provide evidence that many plant-associated bacteria undergo chemical signaling with the plant host via low-molecular-weight compounds. Plant-produced compounds interact with bacterial regulatory proteins that then affect gene expression. Similarly, bacterial quorum-sensing signals result in a range of functional responses in plants. This review attempts to highlight current knowledge in chemical signaling that takes place between pathogenic bacteria and plants. This chemical communication between plant and bacteria, also referred to as interkingdom signaling, will likely become a major research field in the future, as it allows the design of specific strategies to create plants that are resistant to plant pathogens.

Encapsulation of bacteria and viruses in electrospun nanofibres

International Nuclear Information System (INIS)

Salalha, W; Kuhn, J; Dror, Y; Zussman, E

2006-01-01

Bacteria and viruses were encapsulated in electrospun polymer nanofibres. The bacteria and viruses were suspended in a solution of poly(vinyl alcohol) (PVA) in water and subjected to an electrostatic field of the order of 1 kV cm -1 . Encapsulated bacteria in this work (Escherichia coli, Staphylococcus albus) and bacterial viruses (T7, T4, λ) managed to survive the electrospinning process while maintaining their viability at fairly high levels. Subsequently the bacteria and viruses remain viable during three months at -20 and -55 deg. C without a further decrease in number. The present results demonstrate the potential of the electrospinning process for the encapsulation and immobilization of living biological material

[Design of primers to DNA of lactic acid bacteria].

Science.gov (United States)

Lashchevskiĭ, V V; Kovalenko, N K

2003-01-01

Primers LP1-LP2 to the gene 16S rRNA have been developed, which permit to differentiate lactic acid bacteria: Lactobacillus plantarum, L. delbrueckii subsp. bulgaricus and Streptococcus salivarius subsp. thermophilus. The strain-specific and species-specific differentiations are possible under different annealing temperature. Additional fragments, which are synthesized outside the framework of gene 16S rRNA reading, provide for the strain-specific type of differentiation, and the fragment F864 read in the gene 16S rRNA permits identifying L. plantarum.

Historical Trust Levels Predict Current Welfare State Design

DEFF Research Database (Denmark)

Bergh, Andreas; Bjørnskov, Christian

Using cross-sectional data for 76 countries, we apply instrumental variable techniques based on pronoun drop, temperature and monarchies to demonstrate that historical trust levels predict several indicators of current welfare state design, including universalism and high levels of regulatory...... freedom. We argue that high levels of trust and trustworthiness are necessary, but not sufficient, conditions for societies to develop successful universal welfare states that would otherwise be highly vulnerable to free riding and fraudulent behavior. Our results do not exclude positive feedback from...... welfare state universalism to individual trust, although we claim that the important causal link runs from historically trust levels to current welfare state design....

Identification of Lactic Acid Bacteria and Propionic Acid Bacteria using FTIR Spectroscopy and Artificial Neural Networks

Directory of Open Access Journals (Sweden)

Beata Nalepa

2012-01-01

Full Text Available In the present study, lactic acid bacteria and propionic acid bacteria have been identified at the genus level with the use of artificial neural networks (ANNs and Fourier transform infrared spectroscopy (FTIR. Bacterial strains of the genera Lactobacillus, Lactococcus, Leuconostoc, Streptococcus and Propionibacterium were analyzed since they deliver health benefits and are routinely used in the food processing industry. The correctness of bacterial identification by ANNs and FTIR was evaluated at two stages. At first stage, ANNs were tested based on the spectra of 66 reference bacterial strains. At second stage, the evaluation involved 286 spectra of bacterial strains isolated from food products, deposited in our laboratory collection, and identified by genus-specific PCR. ANNs were developed based on the spectra and their first derivatives. The most satisfactory results were reported for the probabilistic neural network, which was built using a combination of W5W4W3 spectral ranges. This network correctly identified the genus of 95 % of the lactic acid bacteria and propionic acid bacteria strains analyzed.

High level radioactive waste management facility design criteria

International Nuclear Information System (INIS)

Sheikh, N.A.; Salaymeh, S.R.

1993-01-01

This paper discusses the engineering systems for the structural design of the Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS). At the DWPF, high level radioactive liquids will be mixed with glass particles and heated in a melter. This molten glass will then be poured into stainless steel canisters where it will harden. This process will transform the high level waste into a more stable, manageable substance. This paper discuss the structural design requirements for this unique one of a kind facility. A special emphasis will be concentrated on the design criteria pertaining to earthquake, wind and tornado, and flooding

Research on high level radioactive waste repository seismic design criteria

International Nuclear Information System (INIS)

Jing Xu

2012-01-01

Review seismic hazard analysis principle and method in site suitable assessment process of Yucca Mountain Project, and seismic design criteria and seismic design basis in primary design process. Demonstrated spatial character of seismic hazard by calculated regional seismic hazard map. Contrasted different level seismic design basis to show their differences and relation. Discussed seismic design criteria for preclosure phrase of high level waste repository and preference goal under beyond design basis ground motion. (author)

Expression levels of matrix metalloproteinase-9 and gram-negative bacteria in symptomatic and asymptomatic periapical lesions.

Science.gov (United States)

Ahmed, Geraldine M; El-Baz, Alaa A; Hashem, Ahmed Abdel Rahman; Shalaan, Abeer K

2013-04-01

The aim of this study was to test the hypothesis that the expression of matrix metalloproteinase (MMP)-9 is significantly elevated in patients with symptomatic apical periodontitis and to correlate this with the detected amount of gram-negative bacteria. Twenty-six patients with periapical lesions involving at least 2 teeth were included in this study. The patients were divided into 2 groups: the symptomatic (SYM) group included 13 patients expressing pain with periapical lesions, and the asymptomatic (ASYM) group included 13 patients expressing no pain. Root canal treatment was performed followed by endodontic surgery and periapical lesion collection. Periapical lesions were serially cut into 4-μ sections. Some sections were processed for histologic examination using hematoxylin-eosin stain. Other sections were processed for immunohistochemical examination. For MMP-9, the area fraction of the positive cells was measured, and the percentage of the MMP-9-immunopositive area to the total area of the microscopic field was calculated. For gram-negative stain cells, the number of cells showing the pink-red color was counted per microscopic field. The Student's t test was used to compare the SYM and ASYM groups. The Pearson correlation coefficient was used to determine a significant correlation between the number of cells and the MMP-9 level. The significance level was set at P ≤ .05. The SYM group showed a statistically significantly higher mean number of gram-negative cells (P = .001) and MMP-9 area percent (P < .001) than the ASYM group. There was a statistically significant positive (r = .927) correlation between the number of gram-negative cells and the MMP-9 area percent (P< .001). There is good evidence to suspect a significant role of gram-negative bacteria and MMP-9 in symptomatic periapical lesions. Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

REGEN: Ancestral Genome Reconstruction for Bacteria.

Science.gov (United States)

Yang, Kuan; Heath, Lenwood S; Setubal, João C

2012-07-18

Ancestral genome reconstruction can be understood as a phylogenetic study with more details than a traditional phylogenetic tree reconstruction. We present a new computational system called REGEN for ancestral bacterial genome reconstruction at both the gene and replicon levels. REGEN reconstructs gene content, contiguous gene runs, and replicon structure for each ancestral genome. Along each branch of the phylogenetic tree, REGEN infers evolutionary events, including gene creation and deletion and replicon fission and fusion. The reconstruction can be performed by either a maximum parsimony or a maximum likelihood method. Gene content reconstruction is based on the concept of neighboring gene pairs. REGEN was designed to be used with any set of genomes that are sufficiently related, which will usually be the case for bacteria within the same taxonomic order. We evaluated REGEN using simulated genomes and genomes in the Rhizobiales order.

DEVELOPMENT OF TOFU PRODUCTION METHOD WITH PROBIOTIC BACTERIA ADDITION

Directory of Open Access Journals (Sweden)

Dorota Zielińska

2015-06-01

Full Text Available The aim of the study was to develop a production method for tofu with probiotic bacteria under laboratory conditions. The works included: selection of a strain and tofu production conditions, and a storage test of the manufactured product. It was concluded that the sensory quality of tofu with the addition of different probiotic cultures did not differ significantly (p>0.01, depending on used strains and their mixtures, and the sample quality was comparable to the commercial product. It was observed that the number of Lactobacillus bacteria in study samples was the factor determining the palatability of tofu (r= 0.75. On the other hand, the sensory quality of products was significantly affected by the production method of tofu with the addition of probiotic bacteria. It was concluded that the formation of curds from soy beverage by the addition of CaSO4, followed by inoculation with Lactobacillus casei ŁOCK 0900 at the amount of 9.26 log CFU/g and incubation at temp. of 37C for 2h as well as for 20h are methods recommended for production tofu with regard to sensory qualities of the final product among all tested methods. The number of lactic acid bacteria in studied tofu samples was maintained at the high level (109-1010 CFU/g, and the number of Bifidobacterium animalis ssp lactis BB-12 bacteria did not exceed 103 CFU/g, whereas the number of Lactobacillus bacteria was equal to 108-109 CFU/g. For the period of 15 days of storage of tofu with probiotic bacteria at the temperature of 4C the number of lactic acid bacteria was maintained at the constant level of approx. 109 CFU/g. It was concluded that it is possible to produce tofu with probiotic bacteria that has acceptable sensory characteristics and a high number of lactic acid bacteria, therefore the product could be considered as a functional one.

Isolation and characterization of heavy metal tolerant bacteria from ...

African Journals Online (AJOL)

Panteka stream is a flowing stream polluted with wastes from the activities of mechanics. Water samples collected at different points of the stream were analysed in order to determine the level of heavy metal contamination and bacteria diversity with the view to elucidating the bioremediating potentials of the bacteria isolates ...

A porous silicon optical microcavity for sensitive bacteria detection

International Nuclear Information System (INIS)

Li Sha; Huang Jianfeng; Cai Lintao

2011-01-01

A porous silicon microcavity (PSM) is highly sensitive to subtle interface changes due to its high surface area, capillary condensation ability and a narrow resonance peak (∼10 nm). Based on the well-defined optical properties of a PSM, we successfully fabricated a bacteria detection chip for molecular or subcellular analysis by surface modification using undecylenic acid (UA), and the specific recognition binding of vancomycin to the D-alanyl-D-alanine of bacteria. The red shift of the PSM resonance peak showed a good linear relationship with bacteria concentration ranging from 100 to 1000 bacteria ml -1 at the level of relative standard deviation of 0.994 and detection limit of 20 bacteria ml -1 . The resulting PSM sensors demonstrated high sensitivity, good reproducibility, fast response and low cost for biosensing.

A porous silicon optical microcavity for sensitive bacteria detection

Science.gov (United States)

Li, Sha; Huang, Jianfeng; Cai, Lintao

2011-10-01

A porous silicon microcavity (PSM) is highly sensitive to subtle interface changes due to its high surface area, capillary condensation ability and a narrow resonance peak (~10 nm). Based on the well-defined optical properties of a PSM, we successfully fabricated a bacteria detection chip for molecular or subcellular analysis by surface modification using undecylenic acid (UA), and the specific recognition binding of vancomycin to the D-alanyl-D-alanine of bacteria. The red shift of the PSM resonance peak showed a good linear relationship with bacteria concentration ranging from 100 to 1000 bacteria ml - 1 at the level of relative standard deviation of 0.994 and detection limit of 20 bacteria ml - 1. The resulting PSM sensors demonstrated high sensitivity, good reproducibility, fast response and low cost for biosensing.

A porous silicon optical microcavity for sensitive bacteria detection

Energy Technology Data Exchange (ETDEWEB)

Li Sha; Huang Jianfeng; Cai Lintao, E-mail: lt.cai@siat.ac.cn [CAS Key Lab of Health Informatics, Shenzhen Key Laboratory of Cancer Nanotechnology, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055 (China)

2011-10-21

A porous silicon microcavity (PSM) is highly sensitive to subtle interface changes due to its high surface area, capillary condensation ability and a narrow resonance peak ({approx}10 nm). Based on the well-defined optical properties of a PSM, we successfully fabricated a bacteria detection chip for molecular or subcellular analysis by surface modification using undecylenic acid (UA), and the specific recognition binding of vancomycin to the D-alanyl-D-alanine of bacteria. The red shift of the PSM resonance peak showed a good linear relationship with bacteria concentration ranging from 100 to 1000 bacteria ml{sup -1} at the level of relative standard deviation of 0.994 and detection limit of 20 bacteria ml{sup -1}. The resulting PSM sensors demonstrated high sensitivity, good reproducibility, fast response and low cost for biosensing.

Lactic acid bacteria affect serum cholesterol levels, harmful fecal enzyme activity, and fecal water content

Directory of Open Access Journals (Sweden)

Chung Myung

2009-06-01

Full Text Available Abstract Background Lactic acid bacteria (LAB are beneficial probiotic organisms that contribute to improved nutrition, microbial balance, and immuno-enhancement of the intestinal tract, as well as lower cholesterol. Although present in many foods, most trials have been in spreads or dairy products. Here we tested whether Bifidobacteria isolates could lower cholesterol, inhibit harmful enzyme activities, and control fecal water content. Methods In vitro culture experiments were performed to evaluate the ability of Bifidobacterium spp. isolated from healthy Koreans (20~30 years old to reduce cholesterol-levels in MRS broth containing polyoxyethanylcholesterol sebacate. Animal experiments were performed to investigate the effects on lowering cholesterol, inhibiting harmful enzyme activities, and controlling fecal water content. For animal studies, 0.2 ml of the selected strain cultures (108~109 CFU/ml were orally administered to SD rats (fed a high-cholesterol diet every day for 2 weeks. Results B. longum SPM1207 reduced serum total cholesterol and LDL levels significantly (p B. longum SPM1207 also increased fecal LAB levels and fecal water content, and reduced body weight and harmful intestinal enzyme activities. Conclusion Daily consumption of B. longum SPM1207 can help in managing mild to moderate hypercholesterolemia, with potential to improve human health by helping to prevent colon cancer and constipation.

Pruning techniques for multi-objective system-level design space exploration

NARCIS (Netherlands)

Piscitelli, R.

2014-01-01

System-level design space exploration (DSE), which is performed early in the design process, is of eminent importance to the design of complex multi-processor embedded system architectures. During system-level DSE, system parameters like, e.g., the number and type of processors, the type and size of

Design and mechanism of action of a novel bacteria-selective antimicrobial peptide from the cell-penetrating peptide Pep-1

International Nuclear Information System (INIS)

Zhu, W.L.; Lan Hongliang; Park, Il-Seon; Kim, Jae Il; Jin, H.Z.; Hahm, Kyung-Soo; Shin, S.Y.

2006-01-01

Here, we report the successful design of a novel bacteria-selective antimicrobial peptide, Pep-1-K (KKTWWKTWWTKWSQPKKKRKV). Pep-1-K was designed by replacing Glu-2, Glu-6, and Glu-11 in the cell-penetrating peptide Pep-1 with Lys. Pep-1-K showed strong antibacterial activity against reference strains (MIC = 1-2 μM) of Gram-positive and Gram-negative bacteria as well as against clinical isolates (MIC = 1-8 μM) of methicillin-resistant Staphylococcus aureus and multidrug-resistant Pseudomonas aeruginosa. In contrast, Pep-1-K did not cause hemolysis of human erythrocytes even at 200 μM. These results indicate that Pep-1-K may be a good candidate for antimicrobial drug development, especially as a topical agent against antibiotic-resistant microorganisms. Tryptophan fluorescence studies indicated that the lack of hemolytic activity of Pep-1-K correlated with its weak ability to penetrate zwitterionic phosphatidylcholine/cholesterol (10:1, w/w) vesicles, which mimic eukaryotic membranes. Furthermore, Pep-1-K caused little or no dye leakage from negatively charged phosphatidylethanolamine/phosphatidylglycerol (7:3, w/w) vesicles, which mimic bacterial membranes but had a potent ability to cause depolarization of the cytoplasmic membrane potential of intact S. aureus cells. These results suggested that Pep-1-K kills microorganisms by not the membrane-disrupting mode but the formation of small channels that permit transit of ions or protons but not molecules as large as calcein

Psychrotrophic metal tolerant bacteria for mobilisation of metals in Antarctic waters

Digital Repository Service at National Institute of Oceanography (India)

Gonsalves, M.J.B.D.

Cold tolerant psychrotrophic bacteria abound in the Antarctic waters. While Antarctic krills are known to concentrate heavy metals at ppm levels, psychrotrophic bacteria from Antarctic fresh and marine waters have been reported to tolerate them...

ISOLATION AND LIGNOCELLULOLYTIC ACTIVITIES OF FIBER-DIGESTING BACTERIA FROM DIGESTIVE TRACT OF TERMITE (Cryptothermes sp.

Directory of Open Access Journals (Sweden)

B.I.M. Tampoebolon

2015-09-01

Full Text Available The objectives of this study were to obtain the fiber-digesting bacteria isolates from termitedigestive tract and to determine the optimum conditions of growth and production of cellulase, xylanaseand ligninase enzyme of isolate. The first study was conducted to isolate and select the fiber-digestingbacteria from the digestive tract of termites based on the highest activity of cellulolytic (S, xylanolytic(X and lignolytic (L. The second study was optimation of the growth conditions of bacteria and theenzyme production due to effect of rice straw substrate and nitrogen. The material used were dry woodtermites, rice straw, and culture medium. The design used was a completely randomized factorial design,in which the first factor was rice straw substrate (1, 2, and 3% W/V, while the second factor wasnitrogen (0.1, 0.2 and 0.3% W/V. Variables measured were cellulase, xylanase and ligninase activities.Results of the first sudy showed that the isolates obtained consisted of 3 types, those were cellulolyticbacteria (S1, S2, and S3, 3 types of bacteria xylanolytic (X1, X2, and X3 and 3 types of bacteria lignolytic(L1, L2, and L3. Meanwhile, results of the second study showed that isolates of S2, X3, and L1 had thehighest activity, those were 1.894 U/mL, 1.722 U/mL and 0.314 U/mL, respectively. In conclusion, the addition of 1% level of rice straw substrate and 0.3% of nitrogen showed the highest enzyme activity oncellulase, xylanase and ligninase.

Money and transmission of bacteria.

Science.gov (United States)

Gedik, Habip; Voss, Timothy A; Voss, Andreas

2013-08-28

Money is one of the most frequently passed items in the world. The aim of this study was to ascertain the survival status of bacteria including Staphylococcus aureus, Escherichia coli, and Vancomycin- Resistant Enterococci (VRE) on banknotes from different countries and the transmission of bacteria to people who come in contact with the banknotes. The survival rate was highest for the Romanian Leu yielding all three microorganisms used after both three and six hours of drying. Furthermore, the Leu was the only banknote to yield VRE after one day of drying. Other currencies either enabled the survival of Extended-Spectrum Beta-Lactamases (ESBL) and VRE (e.g. Euro), but not of MRSA, or the other way round (e.g. US Dollar). While a variety of factors such as community hygiene levels, people's behaviour, and antimicrobial resistance rates at community level obviously have influence on the transmission of resistant microorganisms, the type of banknote-paper may be an additional variable to consider.

Total resistance of native bacteria as an indicator of changes in the water environment

Energy Technology Data Exchange (ETDEWEB)

Harnisz, Monika [Department of Environmental Microbiology, University of Warmia and Mazury in Olsztyn, Prawocheńskiego 1, 10-957 Olsztyn (Poland)

2013-03-15

This study analyzes changes in the total (intrinsic and acquired) resistance of autochthonous bacteria in a river which is a receiver of treated wastewater. In the analyzed samples, tetracycline contamination levels were low and characteristic of surface water bodies. An increase in the populations of tetracycline-resistant and fluoroquinolone-resistant microorganisms was noted in downstream river water samples in comparison with upstream river water samples, but the above trend was not observed in bacteria resistant to macrolides and β-lactams. The counts of doxycycline-resistant bacteria (DOX{sup R}) were significantly correlated with doxycycline levels. The minimum inhibitory concentrations (MICs) for doxycycline in DOX{sup R} isolates were higher in downstream river water than in upstream river water samples. The discharge of treated wastewater had no effect on the multi-drug resistance of oxytetracycline-resistant and doxycycline-resistant isolates. The results of the experiment indicate that the presence of doxycycline-resistant bacteria is a robust indicator of anthropogenic stress in river water. -- Highlights: ► The total resistance of native bacteria in river which is a receiver of treated wastewater was analyzed. ► Tetracyclines contamination levels were low. ► The counts of doxycycline-resistant bacteria were correlated with doxycycline levels. -- The presence of doxycycline-resistant bacteria in rivers can be a robust indicator of anthropogenic stress.

Total resistance of native bacteria as an indicator of changes in the water environment

International Nuclear Information System (INIS)

Harnisz, Monika

2013-01-01

This study analyzes changes in the total (intrinsic and acquired) resistance of autochthonous bacteria in a river which is a receiver of treated wastewater. In the analyzed samples, tetracycline contamination levels were low and characteristic of surface water bodies. An increase in the populations of tetracycline-resistant and fluoroquinolone-resistant microorganisms was noted in downstream river water samples in comparison with upstream river water samples, but the above trend was not observed in bacteria resistant to macrolides and β-lactams. The counts of doxycycline-resistant bacteria (DOX R ) were significantly correlated with doxycycline levels. The minimum inhibitory concentrations (MICs) for doxycycline in DOX R isolates were higher in downstream river water than in upstream river water samples. The discharge of treated wastewater had no effect on the multi-drug resistance of oxytetracycline-resistant and doxycycline-resistant isolates. The results of the experiment indicate that the presence of doxycycline-resistant bacteria is a robust indicator of anthropogenic stress in river water. -- Highlights: ► The total resistance of native bacteria in river which is a receiver of treated wastewater was analyzed. ► Tetracyclines contamination levels were low. ► The counts of doxycycline-resistant bacteria were correlated with doxycycline levels. -- The presence of doxycycline-resistant bacteria in rivers can be a robust indicator of anthropogenic stress

Tumour targeting with systemically administered bacteria.

LENUS (Irish Health Repository)

Morrissey, David

2012-01-31

Challenges for oncology practitioners and researchers include specific treatment and detection of tumours. The ideal anti-cancer therapy would selectively eradicate tumour cells, whilst minimising side effects to normal tissue. Bacteria have emerged as biological gene vectors with natural tumour specificity, capable of homing to tumours and replicating locally to high levels when systemically administered. This property enables targeting of both the primary tumour and secondary metastases. In the case of invasive pathogenic species, this targeting strategy can be used to deliver genes intracellularly for tumour cell expression, while non-invasive species transformed with plasmids suitable for bacterial expression of heterologous genes can secrete therapeutic proteins locally within the tumour environment (cell therapy approach). Many bacterial genera have been demonstrated to localise to and replicate to high levels within tumour tissue when intravenously (IV) administered in rodent models and reporter gene tagging of bacteria has permitted real-time visualisation of this phenomenon. Live imaging of tumour colonising bacteria also presents diagnostic potential for this approach. The nature of tumour selective bacterial colonisation appears to be tumour origin- and bacterial species- independent. While originally a correlation was drawn between anaerobic bacterial colonisation and the hypoxic nature of solid tumours, it is recently becoming apparent that other elements of the unique microenvironment within solid tumours, including aberrant neovasculature and local immune suppression, may be responsible. Here, we consider the pre-clinical data supporting the use of bacteria as a tumour-targeting tool, recent advances in the area, and future work required to develop it into a beneficial clinical tool.

Bacteria as vectors for gene therapy of cancer.

LENUS (Irish Health Repository)

Baban, Chwanrow K

2012-01-31

Anti-cancer therapy faces major challenges, particularly in terms of specificity of treatment. The ideal therapy would eradicate tumor cells selectively with minimum side effects on normal tissue. Gene or cell therapies have emerged as realistic prospects for the treatment of cancer, and involve the delivery of genetic information to a tumor to facilitate the production of therapeutic proteins. However, there is still much to be done before an efficient and safe gene medicine is achieved, primarily developing the means of targeting genes to tumors safely and efficiently. An emerging family of vectors involves bacteria of various genera. It has been shown that bacteria are naturally capable of homing to tumors when systemically administered resulting in high levels of replication locally. Furthermore, invasive species can deliver heterologous genes intra-cellularly for tumor cell expression. Here, we review the use of bacteria as vehicles for gene therapy of cancer, detailing the mechanisms of action and successes at preclinical and clinical levels.

Legionella bacteria in combustion air humidifiers; Legionella i luftuppfuktare foer foerbraenningsluft

Energy Technology Data Exchange (ETDEWEB)

Jeppesen, Jessica; Hansson, Helen; Cederfeldt, Ola; Axby, Fredrik

2007-10-15

Over the last couple of years several outbreaks of Legionnaires' disease has occurred around the world. The source of infection varies, but in many cases the bacteria has been traced back to cooling towers. The common denominator for most of the sources of infection has been water systems with high oxygen levels and a system temperature ranging from 20 to 40 deg C. If a water system furthermore has high levels of other bacteria/microorganisms, then it is also probable that favorable conditions for legionella bacteria exist within the system. These conditions consist well with conditions in combustion air humidifiers in district heating plants and therefore it can be suspected that legionella may thrive also in these types of air humidifiers. In order to examine if legionella bacteria exists in combustion air humidifiers, and in what quantity, ten different district heating plants where selected for a survey. The goal of the survey is to get a general picture of the extent of the occurrence of legionella bacteria in different types of air humidifiers. This was done by taking legionella tests in three different types of air humidifiers in district heating plants. The first step of the testing was conducted by measuring the level of legionella bacteria in water samples from the air humidifiers in the different plants. The water samples were taken from water that circulates in the air humidifiers. A few months later another water sample was taken from the same location. Two district heating plants, where legionella bacteria had been detected, were selected for further testing after compiling the results from the first two tests. The further testing involved fuel gas analysis to see if any of the plants fuel gas contained legionella bacteria. The test results show that a major part of the district heating plants in the survey have heterotrophic bacteria in their water systems, which implies the possibility of growth of legionella bacteria. About half of the plants

REGEN: Ancestral Genome Reconstruction for Bacteria

Directory of Open Access Journals (Sweden)

João C. Setubal

2012-07-01

Full Text Available Ancestral genome reconstruction can be understood as a phylogenetic study with more details than a traditional phylogenetic tree reconstruction. We present a new computational system called REGEN for ancestral bacterial genome reconstruction at both the gene and replicon levels. REGEN reconstructs gene content, contiguous gene runs, and replicon structure for each ancestral genome. Along each branch of the phylogenetic tree, REGEN infers evolutionary events, including gene creation and deletion and replicon fission and fusion. The reconstruction can be performed by either a maximum parsimony or a maximum likelihood method. Gene content reconstruction is based on the concept of neighboring gene pairs. REGEN was designed to be used with any set of genomes that are sufficiently related, which will usually be the case for bacteria within the same taxonomic order. We evaluated REGEN using simulated genomes and genomes in the Rhizobiales order.

Effect of lactic acid bacteria on the textural properties of an edible ...

African Journals Online (AJOL)

This study was aimed to evaluate the effects of different components and the addition of probiotic bacteria of lactic acid bacteria (LAB, Lactobacillus casei) on the physicochemical and textural characteristics of edible films using a response surface Box-Behnken design. The edible films were made of the following ...

In situ determination of the reduction levels of cytochromes b and c in growing bacteria : a case study with N2-fixing Azorhizobium caulinodans

NARCIS (Netherlands)

Pronk, A.F.; Boogerd, F C; Stoof, C.; Oltmann, L F; Stouthamer, A.H.; van Verseveld, H W

1993-01-01

The determination of the in situ reduction levels of cytochromes b and c in growing bacteria is achieved by coupling a chemostat with a dual wavelength spectrophotometer. Visible light absorption spectra of cytochromes present in bacterial cells actively growing in a chemostat at a specific growth

Enrichment using an up-flow column reactor and community structure of marine anammox bacteria from coastal sediment.

Science.gov (United States)

Kindaichi, Tomonori; Awata, Takanori; Suzuki, Yuji; Tanabe, Katsuichiro; Hatamoto, Masashi; Ozaki, Noriatsu; Ohashi, Akiyoshi

2011-01-01

We established an enrichment culture of marine anaerobic ammonium oxidation (anammox) bacteria using an up-flow column reactor fed with artificial sea water supplemented with nitrogen and minerals and inoculated with coastal surface sediment collected from Hiroshima Bay. After 2 months of reactor operation, simultaneous removal of NH(4)(+) and NO(2)(-) was observed, suggesting that an anammox reaction was proceeding. A total nitrogen removal rate of 2.17 g-N L(-1) day(-1) was attained on day 594 while the nitrogen loading rate was 3.33 g-N L(-1) day(-1). Phylogenetic analysis revealed that at least two dominant "Candidatus Scalindua" species were present in this reactor. Moreover, many uncultured bacteria and archaea, including candidate division or ammonia-oxidizing archaea, were present. Fluorescence in situ hybridization (FISH) revealed that anammox bacteria accounted for 85.5 ± 4.5% of the total bacteria at day 393. We also designed two oligonucleotide probes specific to each dominant "Candidatus Scalindua" species. A simultaneous FISH analysis using both probes showed that two different "Candidatus Scalindua" species were clearly recognizable and coexisted during reactor operation, although there was some variation in their abundance. The marine anammox bacteria enriched in this study have potential applications to the treatment of industrial wastewater containing high levels of ammonium and salt.

(VAM) and phosphate solubilizing bacteria (PSB)

African Journals Online (AJOL)

User

2013-09-18

Sep 18, 2013 ... mycorrhiza (VAM), and phosphate solubilising bacteria (PSB) individually and in .... Two-way analysis of variance (ANOVA) was carried out at a 0.05 level of significance on the data and SPSS version 13.0 was used.

DAEDALUS: System-Level Design Methodology for Streaming Multiprocessor Embedded Systems on Chips

NARCIS (Netherlands)

Stefanov, T.; Pimentel, A.; Nikolov, H.; Ha, S.; Teich, J.

2017-01-01

The complexity of modern embedded systems, which are increasingly based on heterogeneous multiprocessor system-on-chip (MPSoC) architectures, has led to the emergence of system-level design. To cope with this design complexity, system-level design aims at raising the abstraction level of the design

Nitrogen fixed by wheat plants as affected by nitrogen fertilizer levels and Non-symbiotic bacteria

Energy Technology Data Exchange (ETDEWEB)

Soliman, S; Aly, S S.M.; Gadalla, A M [Soils and Water Dept., Atomic Energy Authority, Cairo (Egypt); Abou Seeda, M [Soils and Water Dept., National Res. Centre, Cairo (Egypt)

1995-10-01

Inorganic nitrogen is required for all egyptian soils for wheat. Free living and N 2-fixing microorganisms are able associate closely related with the roots of geraminacae. Pot experiment studies were carried out to examine the response of wheat plants to inoculation with Azospirillum Brasilense and Azotobacter Chroococcum, single or in combination, under various levels of ammonium sulfate interaction between both the inoculants increased straw or grain yield as well as N-uptake by wheat plants with increasing N levels. Results showed that grains of wheat plants derived over 19,24 and 15% of its N content from the atmospheric - N 2 (Ndfa) with application of 25,50 and 75 mg N kg-1 soil in the presence of + Azospirillum + azotobacter. The final amount of N 2-fixers. The highest values of N 2-fixed were observed with mixed inoculants followed by inoculation with Azospirillum and then azotobacter. The recovery of applied ammonium sulfate-N was markedly increased by inoculation with combined inoculants, but less in uninoculated treatments. Seeds inoculated with non-symbiotic fixing bacteria could be saved about 25 kg N without much affecting the grain yield. i fig., 4 tabs.

Nitrogen fixed by wheat plants as affected by nitrogen fertilizer levels and Non-symbiotic bacteria

International Nuclear Information System (INIS)

Soliman, S.; Aly, S.S.M.; Gadalla, A.M.; Abou Seeda, M.

1995-01-01

Inorganic nitrogen is required for all egyptian soils for wheat. Free living and N 2-fixing microorganisms are able associate closely related with the roots of geraminacae. Pot experiment studies were carried out to examine the response of wheat plants to inoculation with Azospirillum Brasilense and Azotobacter Chroococcum, single or in combination, under various levels of ammonium sulfate interaction between both the inoculants increased straw or grain yield as well as N-uptake by wheat plants with increasing N levels. Results showed that grains of wheat plants derived over 19,24 and 15% of its N content from the atmospheric - N 2 (Ndfa) with application of 25,50 and 75 mg N kg-1 soil in the presence of + Azospirillum + azotobacter. The final amount of N 2-fixers. The highest values of N 2-fixed were observed with mixed inoculants followed by inoculation with Azospirillum and then azotobacter. The recovery of applied ammonium sulfate-N was markedly increased by inoculation with combined inoculants, but less in uninoculated treatments. Seeds inoculated with non-symbiotic fixing bacteria could be saved about 25 kg N without much affecting the grain yield. i fig., 4 tabs

Lactic acid bacteria affect serum cholesterol levels, harmful fecal enzyme activity, and fecal water content.

Science.gov (United States)

Lee, Do Kyung; Jang, Seok; Baek, Eun Hye; Kim, Mi Jin; Lee, Kyung Soon; Shin, Hea Soon; Chung, Myung Jun; Kim, Jin Eung; Lee, Kang Oh; Ha, Nam Joo

2009-06-11

Lactic acid bacteria (LAB) are beneficial probiotic organisms that contribute to improved nutrition, microbial balance, and immuno-enhancement of the intestinal tract, as well as lower cholesterol. Although present in many foods, most trials have been in spreads or dairy products. Here we tested whether Bifidobacteria isolates could lower cholesterol, inhibit harmful enzyme activities, and control fecal water content. In vitro culture experiments were performed to evaluate the ability of Bifidobacterium spp. isolated from healthy Koreans (20 approximately 30 years old) to reduce cholesterol-levels in MRS broth containing polyoxyethanylcholesterol sebacate. Animal experiments were performed to investigate the effects on lowering cholesterol, inhibiting harmful enzyme activities, and controlling fecal water content. For animal studies, 0.2 ml of the selected strain cultures (108 approximately 109 CFU/ml) were orally administered to SD rats (fed a high-cholesterol diet) every day for 2 weeks. B. longum SPM1207 reduced serum total cholesterol and LDL levels significantly (p water content, and reduced body weight and harmful intestinal enzyme activities. Daily consumption of B. longum SPM1207 can help in managing mild to moderate hypercholesterolemia, with potential to improve human health by helping to prevent colon cancer and constipation.

Experimental clogging of biliary endoprostheses. Role of bacteria, endoprosthesis material, and design

DEFF Research Database (Denmark)

Dowidar, N; Kolmos, H J; Matzen, Peter

1992-01-01

with a low friction coefficient, such as Teflon, contained significantly less sludge than endoprostheses made of materials with a higher friction coefficient, such as polyethylene and polyurethane (p less than 0.05). These results emphasize the role of bacteria in endoprostheses clogging and clearly...

Design-Based Learning for Biology: Genetic Engineering Experience Improves Understanding of Gene Expression

Science.gov (United States)

Ellefson, Michelle R.; Brinker, Rebecca A.; Vernacchio, Vincent J.; Schunn, Christian D.

2008-01-01

Gene expression is a difficult topic for students to learn and comprehend, at least partially because it involves various biochemical structures and processes occurring at the microscopic level. Designer Bacteria, a design-based learning (DBL) unit for high-school students, applies principles of DBL to the teaching of gene expression. Throughout…

Exploring Post-Treatment Reversion of Antimicrobial Resistance in Enteric Bacteria of Food Animals as a Resistance Mitigation Strategy.

Science.gov (United States)

Volkova, Victoriya V; KuKanich, Butch; Riviere, Jim E

2016-11-01

Antimicrobial drug use in food animals is associated with an elevation in relative abundance of bacteria resistant to the drug among the animal enteric bacteria. Some of these bacteria are potential foodborne pathogens. Evidence suggests that at least in the enteric nontype-specific Escherichia coli, after treatment the resistance abundance reverts to the background pre-treatment levels, without further interventions. We hypothesize that it is possible to define the distribution of the time period after treatment within which resistance to the administered drug, and possibly other drugs in case of coselection, in fecal bacteria of the treated animals returns to the background pre-treatment levels. Furthermore, it is possible that a novel resistance mitigation strategy for microbiological food safety could be developed based on this resistance reversion phenomenon. The strategy would be conceptually similar to existing antimicrobial drug withdrawal periods, which is a well-established and accepted mitigation strategy for avoiding violative drug residues in the edible products from the treated animals. For developing resistance-relevant withdrawals, a mathematical framework can be used to join the necessary pharmacological, microbiological, and animal production components to project the distributions of the post-treatment resistance reversion periods in the production animal populations for major antimicrobial drug classes in use. The framework can also help guide design of empirical studies into the resistance-relevant withdrawal periods and development of mitigation approaches to reduce the treatment-associated elevation of resistance in animal enteric bacteria. We outline this framework, schematically and through exemplar equations, and how its components could be formulated.

Low Power Design with High-Level Power Estimation and Power-Aware Synthesis

CERN Document Server

Ahuja, Sumit; Shukla, Sandeep Kumar

2012-01-01

Low-power ASIC/FPGA based designs are important due to the need for extended battery life, reduced form factor, and lower packaging and cooling costs for electronic devices. These products require fast turnaround time because of the increasing demand for handheld electronic devices such as cell-phones, PDAs and high performance machines for data centers. To achieve short time to market, design flows must facilitate a much shortened time-to-product requirement. High-level modeling, architectural exploration and direct synthesis of design from high level description enable this design process. This book presents novel research techniques, algorithms,methodologies and experimental results for high level power estimation and power aware high-level synthesis. Readers will learn to apply such techniques to enable design flows resulting in shorter time to market and successful low power ASIC/FPGA design. Integrates power estimation and reduction for high level synthesis, with low-power, high-level design; Shows spec...

The friendly bacteria within us Commensal bacteria of the intestine ...

Indian Academy of Sciences (India)

Balance of bacterial species in the gut · Immunosensory detection of intestinal bacteria · Pathogenic bacteria release interleukin-8 from HT-29 cells · Lactobacillus GG prevents the IL-8 release in response to pathogens · Effect of probiotic bacteria on chemokine response of epithelia to pathogens · PCR array studies in colon ...

Eubiotics for Food Security at Farm Level: Yeast Cell Wall Products and Their Antimicrobial Potential Against Pathogenic Bacteria.

Science.gov (United States)

Santovito, Elisa; Greco, Donato; Logrieco, Antonio F; Avantaggiato, Giuseppina

2018-06-06

The population increase in the last century was the first cause of the industrialization of animal productions, together with the necessity to satisfy the high food demand and the lack of space and land for the husbandry practices. As a consequence, the farmers moved from extensive to intensive agricultural systems and introduced new practices, such as the administration of antimicrobial drugs. Antibiotics were then used as growth promoters and for disease prevention. The uncontrolled and continuous use of antibiotics contributed to the spread of antibiotic resistance in animals, and this had adverse impacts on human health. This emergence led the European Union, in 2003, to ban the marketing and use of antibiotics as growth promoters, and for prophylaxis purposes from January 2006. This ban caused problems in farms, due to the decrease in animal performances (weight gain, feed conversion ratio, reproduction, etc.), and the rise in the incidence of certain diseases, such as those induced by Clostridium perfringens, Salmonella, Escherichia coli, and Listeria monocytogenes. The economic losses due to the ban increased the interest in researching alternative strategies for the prophylaxis of infectious diseases and for health and growth promotion, such as feed additives. Yeast-based materials, such as cell wall extract, represent promising alternatives to antibiotics, on the base of their prebiotic activity and their claimed capacity to bind enteropathogenic bacteria. Several authors reported examples of the effectiveness of yeast cell wall products in adsorbing bacteria, but there is a lack of knowledge on the mechanisms involved in this interaction. The purpose of this review is to provide an overview of the current approaches used for the control of pathogenic bacteria in feed, with a particular focus on the use of yeast-derived materials proposed to control zoonoses at farm level, and on their effect on animal health.

Level up! the guide to great video game design

CERN Document Server

Rogers, Scott

2014-01-01

Want to design your own video games? Let expert Scott Rogers show you how! If you want to design and build cutting-edge video games but aren't sure where to start, then the SECOND EDITION of the acclaimed Level Up! is for you! Written by leading video game expert Scott Rogers, who has designed the hits Pac Man World, Maximo and SpongeBob Squarepants, this updated edition provides clear and well-thought out examples that forgo theoretical gobbledygook with charmingly illustrated concepts and solutions based on years of professional experience. Level Up! 2nd Edition has been NEWLY EXPANDED to

Chemotaxis by natural populations of coral reef bacteria.

Science.gov (United States)

Tout, Jessica; Jeffries, Thomas C; Petrou, Katherina; Tyson, Gene W; Webster, Nicole S; Garren, Melissa; Stocker, Roman; Ralph, Peter J; Seymour, Justin R

2015-08-01

Corals experience intimate associations with distinct populations of marine microorganisms, but the microbial behaviours underpinning these relationships are poorly understood. There is evidence that chemotaxis is pivotal to the infection process of corals by pathogenic bacteria, but this evidence is limited to experiments using cultured isolates under laboratory conditions. We measured the chemotactic capabilities of natural populations of coral-associated bacteria towards chemicals released by corals and their symbionts, including amino acids, carbohydrates, ammonium and dimethylsulfoniopropionate (DMSP). Laboratory experiments, using a modified capillary assay, and in situ measurements, using a novel microfabricated in situ chemotaxis assay, were employed to quantify the chemotactic responses of natural microbial assemblages on the Great Barrier Reef. Both approaches showed that bacteria associated with the surface of the coral species Pocillopora damicornis and Acropora aspera exhibited significant levels of chemotaxis, particularly towards DMSP and amino acids, and that these levels of chemotaxis were significantly higher than that of bacteria inhabiting nearby, non-coral-associated waters. This pattern was supported by a significantly higher abundance of chemotaxis and motility genes in metagenomes within coral-associated water types. The phylogenetic composition of the coral-associated chemotactic microorganisms, determined using 16S rRNA amplicon pyrosequencing, differed from the community in the seawater surrounding the coral and comprised known coral associates, including potentially pathogenic Vibrio species. These findings indicate that motility and chemotaxis are prevalent phenotypes among coral-associated bacteria, and we propose that chemotaxis has an important role in the establishment and maintenance of specific coral-microbe associations, which may ultimately influence the health and stability of the coral holobiont.

Effect of Pseudomonas and Bacillus bacteria on Yield and Nutrient Uptake in Comparison with Chemical and Organic Fertilizers in Wheat

Directory of Open Access Journals (Sweden)

A. Fallah Nosrat Abad

2015-06-01

Full Text Available The high cost of fertilizers in farming systems, soil pollution and degradation of soil are factors that caused to full use of available renewable nutrient sources of plant (organic and biological with optimal application of fertilizers in order to maintain fertility, structure, biological activity, exchange capacity and water-holding capacity of the water in soil. Therefore, in recent years, according to investigators biofertilizers and organic farming as an alternative to chemical fertilizers has been drawn. Through this study, we examined the effects of triple superphosphate, organic matters and phosphate solubilizing microorganisms on quantitative and qualitative yield of wheat and nutrient uptake. The experiment was carried out in the factorial based on randomized complete block design. The factors were: 1-phosphate solubilizing bacteria in three levels including control, Pseudomonas Putida and Bacillus Coagulans bacteria, 2- triple superphosphate in five levels of 0, 25%, 50%, 75% and 100% and 3-organic matter in 2 levels of 0 and 15 ton/ha in the soil with high phosphorous accessibility (13 mg/kg soil but lower than sufficient limit for plant 15 mg/kg soil. The results showed that the highest amount of yield has been recorded in Pseudomonas Putida bacteria treatment with organic matter and 25% phosphate fertilizer. As a result, at the conditions of this experiment phosphate solubilizing bacteria and organic matter significantly had higher yield than control and their combination with phosphate fertilizer had significant effect on reducing phosphate fertilizer use.

The effect of gamma irradiation on bacteria in stored rice

International Nuclear Information System (INIS)

Kamaruzzaman Sijam.

1987-01-01

The effect of gamma irradiation on bacteria was studied for reducing the total microbial numbers that contaminating raw product under storage. Different storage packages of rice samples were irradiated at various levels of dosage. The results of bacterial isolation, total bacterial count and the isolation of bacterial food pathogenus were discussed. It was observed that the presence of bacteria colonies was suppressed by the presence of yeast and moulds eventhough the number of them decreased as the irradiation dosage levels were increased. (A.J.)

Big bacteria

DEFF Research Database (Denmark)

Schulz, HN; Jørgensen, BB

2001-01-01

A small number of prokaryotic species have a unique physiology or ecology related to their development of unusually large size. The biomass of bacteria varies over more than 10 orders of magnitude, from the 0.2 mum wide nanobacteria to the largest cells of the colorless sulfur bacteria......, Thiomargarita namibiensis, with a diameter of 750 mum. All bacteria, including those that swim around in the environment, obtain their food molecules by molecular diffusion. Only the fastest and largest swimmers known, Thiovulum majus, are able to significantly increase their food supply by motility...... and by actively creating an advective flow through the entire population. Diffusion limitation generally restricts the maximal size of prokaryotic cells and provides a selective advantage for mum-sized cells at the normally low substrate concentrations in the environment. The largest heterotrophic bacteria...

Fecal indicator bacteria at Havana Bay

International Nuclear Information System (INIS)

Lopez Perez, Lisse; Gomez D'Angelo, Yamiris; Beltran Gonzalez, Jesus; Alvarez Valiente, Reinaldo

2013-01-01

Aims: Fecal indicator bacteria concentrations were evaluated in Havana Bay. Methods: Concentrations of traditional fecal indicator bacteria were calculated between April 2010 and February 2011, by MPN methods. Concentrations of thermo tolerant coliform (CTT), Escherichia coli, fecal streptococci (EF), intestinal enterococci (ENT) in seawater, and Clostridium perfringens in sediment surface, were determined. Results: CTT and E. coli levels were far above Cuban water quality standard for indirect contact with water, showing the negative influence of sewage and rivers on the bay. The EF and ENT were measured during sewage spills at the discharge site and they were suitable indicators of fecal contamination, but these indicators didn't show the same behavior in other selected sites. This result comes from its well-known inactivation by solar light in tropical zones and the presumable presence of humid acids in the waters of the bay. Conclusion: Fecal indicator bacteria and its statistical relationships reflect recent and chronic fecal contamination at the bay and near shores.

Exploiting Domain Knowledge in System-level MPSoC Design Space Exploration

NARCIS (Netherlands)

Thompson, M.; Pimentel, A.D.

2013-01-01

System-level design space exploration (DSE), which is performed early in the design process, is of eminent importance to the design of complex multi-processor embedded multimedia systems. During system-level DSE, system parameters like, e.g., the number and type of processors, and the mapping of

Antibiotic-Resistant Enteric Bacteria in Environmental Waters

Directory of Open Access Journals (Sweden)

Lisa M. Casanova

2016-11-01

Full Text Available Sources of antibiotic resistant organisms, including concentrated animal feeding operations (CAFOs, may lead to environmental surface and groundwater contamination with resistant enteric bacteria of public health concern. The objective of this research is to determine whether Salmonella, Escherichia coli, Yersinia enterocolitica, and enterococci resistant to clinically relevant antibiotics are present in surface and groundwater sources in two eastern North Carolina counties, Craven and Wayne. 100 surface and groundwater sites were sampled for Salmonella, E. coli, and enterococci, and the bacteria isolated from these samples were tested for susceptibility to clinically relevant antibiotics. Salmonella were detected at low levels in some surface but not groundwater. E. coli were in surface waters but not ground in both counties. Enterococci were present in surface water and a small number of groundwater sites. Yersinia was not found. Bacterial densities were similar in both counties. For Salmonella in surface water, the most frequent type of resistance was to sulfamethoxazole. There was no ciprofloxacin resistance. There were a few surface water E. coli isolates resistant to chloramphenicol, gentamicin, and ampicillin. Enterococci in surface water had very low levels of resistance to vancomycin, chloramphenicol, ampicillin, and streptomycin. E. coli and enterococci are present more frequently and at higher levels in surface water than Salmonella, but groundwater contamination with any of these organisms was rare, and low levels of resistance can be found sporadically. Resistant bacteria are relatively uncommon in these eastern N.C. surface and groundwaters, but they could pose a risk of human exposure via ingestion or primary contact recreation.

Interleaving methods for hybrid system-level MPSoC design space exploration

NARCIS (Netherlands)

Piscitelli, R.; Pimentel, A.D.; McAllister, J.; Bhattacharyya, S.

2012-01-01

System-level design space exploration (DSE), which is performed early in the design process, is of eminent importance to the design of complex multi-processor embedded system architectures. During system-level DSE, system parameters like, e.g., the number and type of processors, the type and size of

Big bacteria

DEFF Research Database (Denmark)

Schulz, HN; Jørgensen, BB

2001-01-01

A small number of prokaryotic species have a unique physiology or ecology related to their development of unusually large size. The biomass of bacteria varies over more than 10 orders of magnitude, from the 0.2 mum wide nanobacteria to the largest cells of the colorless sulfur bacteria...... and by actively creating an advective flow through the entire population. Diffusion limitation generally restricts the maximal size of prokaryotic cells and provides a selective advantage for mum-sized cells at the normally low substrate concentrations in the environment. The largest heterotrophic bacteria......, the 80 x 600 mum large Epulopiscium sp. from the gut of tropical fish, are presumably living in a very nutrient-rich medium. Many large bacteria contain numerous inclusions in the cells that reduce the volume of active cytoplasm. The most striking examples of competitive advantage from large cell size...

Distribution of bacteria in frozen shrimps and their decontamination by gamma irradiation

Energy Technology Data Exchange (ETDEWEB)

Ito, Hitoshi; Adulyatham, P.; Ishigaki, Isao

1987-11-01

Six samples of frozen shrimps were obtained through importing company mainly from South-east Asian countries. Five samples of frozen shrimps contained 1.5 x 10/sup 5/ to 6.2 x 10/sup 6/ per gram of total aerobic bacteria, and 4 samples contained 1.4 x 10/sup 2/ to 2.2 x 10/sup 3/ per gram of coliforms, which are higher contamination than Japanese standard of hygenic level for frozen food products (total counts below 10/sup 5/ per gram and no coliforms). The dominant bacteria in total counts were consisted with psychrotrophic Moraxella, Arthrobacter, Micrococcus, Acinetobacter, Flavobacterium, Corynebacterium, Pseudomonas and etc, in all kinds of frozen shrimps. Salmonellae or enteric Vibrio were could not isolated by ordinary isolation methods, and there were isolated many strains of Proteus mirabilis instead of these bacteria. Necessary dose of gamma irradiation for decontamination of bacteria to hygenic level was decided as 3 approx. 5 kGy from the inactivation curves of total bacteria, coliforms, Proteus mirabilis and Salmonella typhymurium in frozen shrimps. Off-odor was suppressed by frozen condition of irradiation.

Distribution of bacteria in frozen shrimps and their decontamination by gamma irradiation

International Nuclear Information System (INIS)

Ito, Hitoshi; Adulyatham, P.; Ishigaki, Isao

1987-01-01

Six samples of frozen shrimps were obtained through importing company mainly from South-east Asian countries. Five samples of frozen shrimps contained 1.5 x 10 5 to 6.2 x 10 6 per gram of total aerobic bacteria, and 4 samples contained 1.4 x 10 2 to 2.2 x 10 3 per gram of coliforms, which are higher contamination than Japanese standard of hygenic level for frozen food products (total counts below 10 5 per gram and no coliforms). The dominant bacteria in total counts were consisted with psychrotrophic Moraxella, Arthrobacter, Micrococcus, Acinetobacter, Flavobacterium, Corynebacterium, Pseudomonas and etc, in all kinds of frozen shrimps. Salmonellae or enteric Vibrio were could not isolated by ordinary isolation methods, and there were isolated many strains of Proteus mirabilis instead of these bacteria. Necessary dose of gamma irradiation for decontamination of bacteria to hygenic level was decided as 3 ∼ 5 kGy from the inactivation curves of total bacteria, coliforms, Proteus mirabilis and Salmonella typhymurium in frozen shrimps. Off-odor was suppressed by frozen condition of irradiation. (author)

Significance of bacteria associated with invertebrates in drinking water distribution networks.

Science.gov (United States)

Wolmarans, E; du Preez, H H; de Wet, C M E; Venter, S N

2005-01-01

The implication of invertebrates found in drinking water distribution networks to public health is of concern to water utilities. Previous studies have shown that the bacteria associated with the invertebrates could be potentially pathogenic to humans. This study investigated the level and identity of bacteria commonly associated with invertebrates collected from the drinking water treatment systems as well as from the main pipelines leaving the treatment works. On all sampling occasions bacteria were isolated from the invertebrate samples collected. The highest bacterial counts were observed for the samples taken before filtration as was expected. There were, however, indications that optimal removal of invertebrates from water did not always occur. During the investigation, 116 colonies were sampled for further identification. The isolates represent several bacterial genera and species that are pathogenic or opportunistic pathogens of humans. Diarrhoea, meningitis, septicaemia and skin infections are among the diseases associated with these organisms. The estimated number of bacteria that could be associated with a single invertebrate (as based on average invertebrate numbers) could range from 10 to 4000 bacteria per organism. It can, therefore, be concluded that bacteria associated with invertebrates might under the worst case scenario pose a potential health risk to water users. In the light of the above findings it is clear that invertebrates in drinking water should be controlled at levels as low as technically and economically feasible.

Pulling Helices inside Bacteria: Imperfect Helices and Rings

Science.gov (United States)

Allard, Jun F.; Rutenberg, Andrew D.

2009-04-01

We study steady-state configurations of intrinsically-straight elastic filaments constrained within rod-shaped bacteria that have applied forces distributed along their length. Perfect steady-state helices result from axial or azimuthal forces applied at filament ends, however azimuthal forces are required for the small pitches observed for MreB filaments within bacteria. Helix-like configurations can result from distributed forces, including coexistence between rings and imperfect helices. Levels of expression and/or bundling of the polymeric protein could mediate this coexistence.

Temperate and lytic bacteriophages programmed to sensitize and kill antibiotic-resistant bacteria.

Science.gov (United States)

Yosef, Ido; Manor, Miriam; Kiro, Ruth; Qimron, Udi

2015-06-09

The increasing threat of pathogen resistance to antibiotics requires the development of novel antimicrobial strategies. Here we present a proof of concept for a genetic strategy that aims to sensitize bacteria to antibiotics and selectively kill antibiotic-resistant bacteria. We use temperate phages to deliver a functional clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated (Cas) system into the genome of antibiotic-resistant bacteria. The delivered CRISPR-Cas system destroys both antibiotic resistance-conferring plasmids and genetically modified lytic phages. This linkage between antibiotic sensitization and protection from lytic phages is a key feature of the strategy. It allows programming of lytic phages to kill only antibiotic-resistant bacteria while protecting antibiotic-sensitized bacteria. Phages designed according to this strategy may be used on hospital surfaces and hand sanitizers to facilitate replacement of antibiotic-resistant pathogens with sensitive ones.

Effects of Phosphorus Solubilizing Bacteria and Nitrogen on the Qualitative and Quantitative Properties of Tuberose (Polianthes tuberosa

Directory of Open Access Journals (Sweden)

T. Taher

2016-02-01

Full Text Available Introduction: In Iran, tuberose is ranked the forth after gladiolus, rose and carnation. These flowers are known as high quality products among which maximum exportation belongs to tuberose and gladiolus. In plant cultivation and development, adequate provision of nutrients is of crucial importance. Tuberose needs plenty of nutrients to obtain the desirable quality and flowering. Hence, tuberose balanced nutrition can play an important role in increasing the yield and quality of its flowers. Nitrogen is a deciding factor for the plant growth and physiology. This nutritional element contributes to the formation of amino acids, proteins, nucleic acids and other cellular components that are required for the construction of new cells. Bio fertilizers containing phosphate solubilizing bacteria (bacillus and pseudomonas have microorganisms which are beneficial to the soil; these bacteria are conducive to the production of biological materials and as a consequence to plant development. According to a report by Rawia Eid et al., (2009 the application of phosphate solubilizing bacteria increased the growth rate of matthiola cut flower and improved its quality. In another study on soybean, it was observed that the application of phosphate solubilizing bacteria led to a rise in the plant dry matter content. Considering the contributory role of nitrogen and phosphorous in increasing the yield and quality of ornamental plants, the aim of this research was to examine the impact of different nitrogen levels and phosphate solubilizing bacteria on the yield and qualitative properties of tuberose cut flower. Materials and Methods: This research was carried out in a greenhouse in the city of Zanjan in Iran in 2011 through a factorial-form experiment based on a randomized complete block design with three replications and twelve treatments performed on tuberose double cultivar. The treatments included bio fertilizer containing phosphate solubilizing bacteria at

Bacteria-Targeting Nanoparticles for Managing Infections

Science.gov (United States)

Radovic-Moreno, Aleksandar Filip

Bacterial infections continue to be a significant concern particularly in healthcare settings and in the developing world. Current challenges include the increasing spread of drug resistant (DR) organisms, the side effects of antibiotic therapy, the negative consequences of clearing the commensal bacterial flora, and difficulties in developing prophylactic vaccines. This thesis was an investigation of the potential of a class of polymeric nanoparticles (NP) to contribute to the management of bacterial infections. More specifically, steps were taken towards using these NPs (1) to achieve greater spatiotemporal control over drug therapy by more targeted antibiotic delivery to bacteria, and (2) to develop a prophylactic vaccine formulation against the common bacterial sexually transmitted disease (STD) caused by Chlamydia trachomatis. In the first part, we synthesized polymeric NPs containing poly(lactic-co-glycolic acid)-block-poly(L-histidine)-block-poly(ethylene glycol) (PLGA-PLH-PEG). We show that these NPs are able to bind to bacteria under model acidic infection conditions and are able to encapsulate and deliver vancomycin to inhibit the growth of Staphylococcus aureus bacteria in vitro. Further work showed that the PLGA-PLH-PEG-based NPs demonstrated the potential for competition for binding bacteria at a site of infection from soluble protein and model phagocytic and tissue-resident cells in a NP composition dependent manner. The NPs demonstrated low toxicity in vitro, were well tolerated by mice in vivo, and circulated in the blood on timescales comparable to control PLGA-PEG NPs. In the second part, we used PLGA-PLH-PEG-based NPs to design a prophylactic vaccine against the obligate intracellular bacterium Chlamydia trachomatis, the most common cause of bacterial STD in the world. Currently, no vaccines against this pathogen are approved for use in humans. We first formulated NPs encapsulating the TLR7 agonist R848 conjugated to poly(lactic acid) (R848-PLA

[Spectrum and susceptibility of preoperative conjunctival bacteria].

Science.gov (United States)

Fernández-Rubio, M E; Cuesta-Rodríguez, T; Urcelay-Segura, J L; Cortés-Valdés, C

2013-12-01

To describe the conjunctival bacterial spectrum of our patients undergoing intraocular surgery and their antibiotic sensitivity during the study period. A retrospective study of preoperative conjunctival culture of patients consecutively scheduled for intraocular surgery from 21 February 2011 to 1 April 2013. Specimens were directly seeded onto blood-agar and MacConkey-agar (aerobiosis incubation, 2 days), and on chocolate-agar (6% CO2 incubation, 7 days). The identified bacteria were divided into 3 groups according to their origin; the bacteria susceptibility tests were performed on those more pathogenic and on some of the less pathogenic when more than 5 colonies were isolated. The sensitivity of the exigent growing bacteria was obtained with disk diffusion technique, and for of the non-exigent bacteria by determining their minimum inhibitory concentration. The Epidat 3.1 program was used for statistical calculations. A total of 13,203 bacteria were identified in 6,051 cultures, with 88.7% being typical colonizers of conjunctiva (group 1), 8.8% typical of airways (group 2), and the remaining 2.5% of undetermined origin (group 3). 530 cultures (8.8%) were sterile. The sensitivity of group 1 was: 99% vancomycin, 95% rifampicin, 87% chloramphenicol, 76% tetracycline. Levels of co-trimoxazole, aminoglycosides, quinolones, β-lactams and macrolides decreased since 2007. The group 2 was very sensitive to chloramphenicol, cefuroxime, rifampicin, ciprofloxacin and amoxicillin/clavulanate. In group 3, to levofloxacin 93%, ciprofloxacin 89%, tobramycin 76%, but ceftazidime 53% and cefuroxime 29% decreased. None of the tested antibiotics could eradicate all possible conjunctival bacteria. Bacteria living permanently on the conjunctiva (group 1) have achieved higher resistance than the eventual colonizers. Copyright © 2013 Sociedad Española de Oftalmología. Published by Elsevier Espana. All rights reserved.

Detection of multiple potentially pathogenic bacteria in Matang mangrove estuaries, Malaysia.

Science.gov (United States)

Ghaderpour, Aziz; Mohd Nasori, Khairul Nazrin; Chew, Li Lee; Chong, Ving Ching; Thong, Kwai Lin; Chai, Lay Ching

2014-06-15

The deltaic estuarine system of the Matang Mangrove Forest Reserve of Malaysia is a site where several human settlements and brackish water aquaculture have been established. Here, we evaluated the level of fecal indicator bacteria (FIB) and the presence of potentially pathogenic bacteria in the surface water and sediments. Higher levels of FIB were detected at downstream sampling sites from the fishing village, indicating it as a possible source of anthropogenic pollution to the estuary. Enterococci levels in the estuarine sediments were higher than in the surface water, while total coliforms and E. coli in the estuarine sediments were not detected in all samples. Also, various types of potentially pathogenic bacteria, including Klebsiella pneumoniae, Serratia marcescens and Enterobacter cloacae were isolated. The results indicate that the Matang estuarine system is contaminated with various types of potential human bacterial pathogens which might pose a health risk to the public. Copyright © 2014 Elsevier Ltd. All rights reserved.

Tolerance of anaerobic bacteria to chlorinated solvents.

Science.gov (United States)

Koenig, Joanna C; Groissmeier, Kathrin D; Manefield, Mike J

2014-01-01

The aim of this research was to evaluate the effects of four chlorinated aliphatic hydrocarbons (CAHs), perchloroethene (PCE), carbon tetrachloride (CT), chloroform (CF) and 1,2-dichloroethane (1,2-DCA), on the growth of eight anaerobic bacteria: four fermentative species (Escherichia coli, Klebsiella sp., Clostridium sp. and Paenibacillus sp.) and four respiring species (Pseudomonas aeruginosa, Geobacter sulfurreducens, Shewanella oneidensis and Desulfovibrio vulgaris). Effective concentrations of solvents which inhibited growth rates by 50% (EC50) were determined. The octanol-water partition coefficient or log Po/w of a CAH proved a generally satisfactory measure of its toxicity. Most species tolerated approximately 3-fold and 10-fold higher concentrations of the two relatively more polar CAHs CF and 1,2-DCA, respectively, than the two relatively less polar compounds PCE and CT. EC50 values correlated well with growth rates observed in solvent-free cultures, with fast-growing organisms displaying higher tolerance levels. Overall, fermentative bacteria were more tolerant to CAHs than respiring species, with iron- and sulfate-reducing bacteria in particular appearing highly sensitive to CAHs. These data extend the current understanding of the impact of CAHs on a range of anaerobic bacteria, which will benefit the field of bioremediation.

[Methanotrophic bacteria of acid sphagnum bogs].

Science.gov (United States)

Dedysh, S N

2002-01-01

Acid sphagnum bogs cover a considerable part of the territory of Russia and are an important natural source of biogenic methane, which is formed in their anaerobic layers. A considerable portion of this methane is consumed in the aerobic part of the bog profile by acidophilic methanotrophic bacteria, which comprise the methane filter of sphagnum bogs and decrease CH4 emission to the atmosphere. For a long time, these bacteria escaped isolation, which became possible only after the elucidation of the optimal conditions of their functioning in situ: pH 4.5 to 5.5; temperature, from 15 to 20 degrees C; and low salt concentration in the solution. Reproduction of these conditions and rejection of earlier used media with a high content of biogenic elements allowed methanotrophic bacteria of two new genera and species--Methylocella palustris and Methylocapsa acidophila--to be isolated from the peat of sphagnum bogs of the northern part of European Russia and West Siberia. These bacteria are well adapted to the conditions in cold, acid, oligotrophic sphagnum bogs. They grow in a pH range of 4.2-7.5 with an optimum at 5.0-5.5, prefer moderate temperatures (15-25 degrees C) and media with a low content of mineral salts (200-500 mg/l), and are capable of active nitrogen fixation. Design of fluorescently labeled 16S rRNA-targeted oligonucleotide probes for the detection of Methylocella palustris and Methylocapsa acidophila and their application to the analysis of sphagnum peat samples showed that these bacteria represent dominant populations of methanotrophs with a density of 10(5)-10(6) cells/g peat. In addition to Methylocella and Methylocapsa populations, one more abundant population of methanotrophs was revealed (10(6) cells/g peat), which were phylogenetically close to the genus Methylocystis.

Proteolytic and ACE-inhibitory activities of probiotic yogurt containing non-viable bacteria as affected by different levels of fat, inulin and starter culture.

Science.gov (United States)

Shakerian, Mansour; Razavi, Seyed Hadi; Ziai, Seyed Ali; Khodaiyan, Faramarz; Yarmand, Mohammad Saeid; Moayedi, Ali

2015-04-01

In this study, the effects of fat (0.5 %, 3.2 % and 5.0 %), inulin (0.0 and 1.0 %) and starter culture (0.0 %, 0.5 %, 1.0 % and 1.5 %) on the angiotensin converting enzyme (ACE)-inhibitory activity of probiotic yogurt containing non-viable bacteria were assessed. Proteolytic activities of bacteria were also investigated. Yogurts were prepared either using a sole yogurt commercial culture including Streptococcus thermophilus and Lactobacillus delbrueckii subs. bulgaricus or bifidobacterium animalis BB-12 and Lactobacillus acidophilus La5 in addition to yogurt culture. Relative degrees of proteolysis were found to be considerably higher in yogurt samples than UHT milk as the control. Both regular and probiotic yogurts showed considerable ACE-inhibitory activities. Results showed that degree of proteolysis was not influenced by different fat contents, while was increased by high concentration of starter culture (1.5 % w/w) and reduced by inulin (1 % w/w). ACE-inhibitory activities of yogurt were also negatively affected by the presence of inulin and high levels of fat (5 % w/w). Moreover, yogurt containing probiotic bacteria showed higher inhibitory against ACE in comparison to the yogurt prepared with non-probiotic strains.

Topological Design and Modulation Strategy for Buck-Boost Three-Level Inverters

DEFF Research Database (Denmark)

Gao, Feng; Loh, Poh Chiang; Teodorescu, Remus

2009-01-01

To date, designed topologies for dc-ac inversion with both voltage buck and boost capabilities are mainly focused on two-level circuitries with extensions to three-level possibilities left nearly unexplored. Contributing to this area of research, this paper presents the design of a number of viable...... can perform distinct five-level line voltage and three-level phase voltage switching by simply controlling the active switches located in the designed voltage boost section of the circuits. As a cost saving option, one active switch can further be removed from the voltage boost section of the circuits...... buck-boost threelevel inverters that can also support bidirectional power conversion. The proposed front-end circuitry is developed from the C´ ukderived buck-boost two-level inverter, and by using the "alternative phase opposition disposition" modulation scheme, the buck-boost three-level inverters...

Periodontal disease associated with red complex bacteria in dogs.

Science.gov (United States)

Di Bello, A; Buonavoglia, A; Franchini, D; Valastro, C; Ventrella, G; Greco, M F; Corrente, M

2014-03-01

Red complex bacteria (Treponema denticola, Tannerella forsythia and Porphyromonas gingivalis) play a major role in the aetiology of periodontal disease in humans. This study was designed to evaluate the association of such bacteria with periodontal disease in dogs. Seventy-three subgingival samples taken from dogs ranging from 2 months to 12 years (median age 4 years) were tested for red complex bacteria using a polymerase chain reaction assay. Thirty-six of 73 (49 · 3%) dogs were found to be positive for T. forsythia and P. gingivalis. Dogs with gingivitis or periodontitis were more likely to be infected with T. forsythia and P. gingivalis [odds ratio (OR) 5 · 4 (confidence interval (CI) 1 · 9-15 · 6), P = 0 · 002] than healthy animals. Only 3 (4 · 1%) of 73 samples were positive for red complex bacteria, but the association with periodontal disease was not significant. The results indicate that involvement of red complex bacteria in periodontal disease in dogs is similar to that observed in humans. Only the concurrent presence of T. forsythia and P. gingivalis were correlated to periodontal disease in dogs in this study. © 2014 British Small Animal Veterinary Association.

Single and mixed formulations of inoculants with diazotrophic bacteria, under different nitrogen rates and on the paddy rice crop

Directory of Open Access Journals (Sweden)

Paula Bianchet

2013-12-01

Full Text Available The use of diazotrophic bacteria as a biological input for the production of paddy rice can reduce nitrogen fertilizer applications and contribute to plant development. The use of mixed inoculants’ formulations can increase the efficiency of nitrogen fixation biological process. The objective of this study was to evaluate the effect of single and mixed formulations of inoculants with diazotrophic bacteria on the initial growth of paddy rice plants under different levels of N. The experiment was set in a greenhouse. Treatments consisted of four types of inoculation (no inoculation, inoculation with the isolated AI UDESC 27, inoculation with the isolated FE UDESC 22, and inoculation with the mixed formulation of isolated AI UDESC UDESC 27 and FE UDESC 22; and two levels of mineral nitrogen (30 and 60 mg kg-1 of N. The cultivar used was Epagri 109, which presents late maturity (over 140 days and high yield potential. Treatments were arranged in a factorial design (4 x 2 with five replicates. The experimental design was completely randomized. Inoculation with diazotrophic bacteria reduced by 18% and 26% shoot and root dry matter of rice plants, respectively. Plants also presented lower root area and volume when they were inoculated. There was no significant effect of inoculation and nitrogen rates on the number of leaves and tillers produced per plant or shoot nitrogen accumulation. The results showed that the isolated used in this work were not effective to stimulate shoot and root growth of cv Epagri 109, regardless of formulation type and rate of N.

Survival of heterotrophic bacteria in water environment under substrate deficiency

International Nuclear Information System (INIS)

Toth, D.

1989-01-01

The relationship between metabolic changes and survival of bacteria in the water environment under substrate deficiency was studied. The main factors supporting cell survival were cryptic growth, utilization of endogenous reserve substances and reorganization of metabolic activities. Based on the utilization of cell-free extract or lysates from dead bacteria, an Enterobacter aerogenes cell suspension yielded 50% more colonies. Metabolic processes of starved heterotrophic bacteria changed markedly and became stabilized at a lower level depending on species involved. The rate of utilization of endogenous reserve substances as indicated by endogenous respiration was related to the rate of cell mortality. Of the test bacteria, Pseudomonas fluorescens showed the lowest rates of endogenous respiration and mortality while in Enterobacter aerogenes these two rates were the highest. (author). 3 figs., 2 tabs.., 16 refs

Active targeting of tumor cells using light emitting bacteria

International Nuclear Information System (INIS)

Moon, Sung Min; Min, Jung Joon; Hong, Yeong Jin; Kim, Hyun Ju; Le, Uuenchi N.; Rhee, Joon Haeng; Song, Ho Chun; Heo, Young Jun; Bom, Hee Seung; Choy, Hyon E

2004-01-01

The presence of bacteria and viruses in human tumors has been recognized for more than 50 years. Today, with the discovery of bacterial strains that specifically target tumors, and aided by genomic sequencing and genetic engineering, there is new interest in the use of bacteria as tumor vectors. Here, we show that bacteria injected intravenously into live animals entered and replicated in solid tumors and metastases using the novel imaging technology of biophotonics. Bioluminescence operon (LuxCDABE) or fluorescence protein, GFP) has been cloned into pUC19 plasmid to engineer pUC19lux or pUC19gfp. Engineered plasmid was transformed into different kinds of wild type (MG1655) or mutant E. coli (DH5, ppGpp, fnr, purE, crpA, flagella, etc.) strains to construct light emitting bacteria. Xenograft tumor model has been established using CT26 colon cancer cell line. Light emitting bacteria was injected via tail vein into tumor bearing mouse. In vivo bioluminescence imaging has been done after 20 min to 14 days of bacterial injection. We observed localization of tumors by light-emitting E. coli in tumor (CT-26) bearing mice. We confirmed the presence of light-emitting bacteria under the fluorescence microscope with E. coli expressing GFP. Althoug varying mutants strain with deficient invading function has been found in tumor tissues, mutant strains of movement (flagella) couldn't show any light signal from the tumor tissue under the cooled CCD camera, indicating bacteria may actively target the tumor cells. Based on their 'tumor-finding' nature, bacteria may be designed to carry multiple genes or drugs for detection and treatment of cancer, such as prodrug-converting enzymes, toxins, angiogenesis inhibitors and cytokines

Symbiotic Bacteria Enable Olive Fly Larvae to Overcome Host Defenses

International Nuclear Information System (INIS)

Ben-Yosef, Michael; Yuval, Boaz; Pasternak, Zohar; Jurkevitch, Edouard

2016-01-01

Ripe fruit offer readily available nutrients for many animals, including fruit fly larvae (Diptera: Tephritidae) and their associated rot-inducing bacteria. Yet, during most of their ontogeny, fruit remain chemically defended and effectively suppress herbivores and pathogens by high levels of secondary metabolites. Olive flies (Bactrocera oleae) are uniquely able to develop in unripe olives. Unlike other frugivorous tephritids, the larvae maintain bacteria confined within their midgut caeca. We examined the interaction between larvae, their associated bacteria, and fruit chemical defence, hypothesizing that bacterial contribution to larval development is contingent on the phenology of fruit defensive chemistry. We demonstrate that larvae require their natural complement of bacteria (Candidatus Erwinia dacicola: Enterobacteriaceae) in order to develop in unripe olives. Conversely, when feeding on ripe fruit, larval development proceeds independently of these bacteria. Our experiments suggest that bacteria counteract the inhibitory effect of oleuropein—the principal phenolic glycoside in unripe olives. In light of these results, we suggest that the unique symbiosis in olive flies, compared with other frugivorous tephritids, is understood by considering the relationship between the fly, bacteria and fruit chemistry. When applied in an evolutionary context, this approach may also point out the forces which shaped symbioses across the Tephritidae. (author)

Incorporation of therapeutically modified bacteria into gut microbiota inhibits obesity.

Science.gov (United States)

Chen, Zhongyi; Guo, Lilu; Zhang, Yongqin; Walzem, Rosemary L; Pendergast, Julie S; Printz, Richard L; Morris, Lindsey C; Matafonova, Elena; Stien, Xavier; Kang, Li; Coulon, Denis; McGuinness, Owen P; Niswender, Kevin D; Davies, Sean S

2014-08-01

Metabolic disorders, including obesity, diabetes, and cardiovascular disease, are widespread in Westernized nations. Gut microbiota composition is a contributing factor to the susceptibility of an individual to the development of these disorders; therefore, altering a person's microbiota may ameliorate disease. One potential microbiome-altering strategy is the incorporation of modified bacteria that express therapeutic factors into the gut microbiota. For example, N-acylphosphatidylethanolamines (NAPEs) are precursors to the N-acylethanolamide (NAE) family of lipids, which are synthesized in the small intestine in response to feeding and reduce food intake and obesity. Here, we demonstrated that administration of engineered NAPE-expressing E. coli Nissle 1917 bacteria in drinking water for 8 weeks reduced the levels of obesity in mice fed a high-fat diet. Mice that received modified bacteria had dramatically lower food intake, adiposity, insulin resistance, and hepatosteatosis compared with mice receiving standard water or control bacteria. The protective effects conferred by NAPE-expressing bacteria persisted for at least 4 weeks after their removal from the drinking water. Moreover, administration of NAPE-expressing bacteria to TallyHo mice, a polygenic mouse model of obesity, inhibited weight gain. Our results demonstrate that incorporation of appropriately modified bacteria into the gut microbiota has potential as an effective strategy to inhibit the development of metabolic disorders.

International Space Station Bacteria Filter Element Service Life Evaluation

Science.gov (United States)

Perry, J. L.

2005-01-01

The International Space Station (ISS) uses high-efficiency particulate air filters to remove particulate matter from the cabin atmosphere. Known as bacteria filter elements (BFEs), there are 13 elements deployed on board the ISS's U.S. segment in the flight 4R assembly level. The preflight service life prediction of 1 yr for the BFEs is based upon engineering analysis of data collected during developmental testing that used a synthetic dust challenge. While this challenge is considered reasonable and conservative from a design perspective, an understanding of the actual filter loading is required to best manage the critical ISS program resources. Testing was conducted on BFEs returned from the ISS to refine the service life prediction. Results from this testing and implications to ISS resource management are provided.

Uptake of crude petroleum hydrocarbons by mudflat bacteria ...

African Journals Online (AJOL)

SERVER

2007-08-06

Aug 6, 2007 ... bacteria exposed to nitrogenous fertilizer plant ... accompanied by a rapid decline in the level of crude petroleum in the amended .... conductivity, turbidity, salinity, dissolved oxygen (fresh sample only) ... Nutrient uptake was.

Bacteria and lignin degradation

Institute of Scientific and Technical Information of China (English)

Jing LI; Hongli YUAN; Jinshui YANG

2009-01-01

Lignin is both the most abundant aromatic (phenolic) polymer and the second most abundant raw material.It is degraded and modified by bacteria in the natural world,and bacteria seem to play a leading role in decomposing lignin in aquatic ecosystems.Lignin-degrading bacteria approach the polymer by mechanisms such as tunneling,erosion,and cavitation.With the advantages of immense environmental adaptability and biochemical versatility,bacteria deserve to be studied for their ligninolytic potential.

Zonulin Regulates Intestinal Permeability and Facilitates Enteric Bacteria Permeation in Coronary Artery Disease

OpenAIRE

Li, Chuanwei; Gao, Min; Zhang, Wen; Chen, Caiyu; Zhou, Faying; Hu, Zhangxu; Zeng, Chunyu

2016-01-01

Several studies have reported an association between enteric bacteria and atherosclerosis. Bacterial 16S ribosomal RNA (rRNA) gene belong to Enterobacteriaceae have been detected in atherosclerotic plaques. How intestinal bacteria go into blood is not known. Zonulin reversibly modulate intestinal permeability (IP), the circulating zonulin levels were increased in diabetes, obesity, all of which are risk factors for atherosclerosis. It is unclear whether the circulating zonulin levels were cha...

A truck cask design for shipping defense high-level waste

International Nuclear Information System (INIS)

Madsen, M.M.; Zimmer, A.

1985-01-01

The Defense High-Level Waste (DHLW) cask is a Type B packaging currently under development by the U.S. Department of Energy (DOE). This truck cask has been designed to initially transport borosilicate glass waste from the Defense Waste Processing Facility (DWPF) to the Waste Isolation Pilot Plant (WIPP). Specific program activities include designing, testing, certifying, and fabricating a prototype legal-weight truck cask system. The design includes such state-of-the-art features as integral impact limiters and remote handling features. A replaceable shielding liner provides the flexibility for shipping a wide range of waste types and activity levels

Comparative innate immune interactions of human and bovine secretory IgA with pathogenic and non-pathogenic bacteria.

Science.gov (United States)

Hodgkinson, Alison J; Cakebread, Julie; Callaghan, Megan; Harris, Paul; Brunt, Rachel; Anderson, Rachel C; Armstrong, Kelly M; Haigh, Brendan

2017-03-01

Secretory IgA (SIgA) from milk contributes to early colonization and maintenance of commensal/symbiotic bacteria in the gut, as well as providing defence against pathogens. SIgA binds bacteria using specific antigenic sites or non-specifically via its glycans attached to α-heavy-chain and secretory component. In our study, we tested the hypothesis that human and bovine SIgA have similar innate-binding activity for bacteria. SIgAs, isolated from human and bovine milk, were incubated with a selection of commensal, pathogenic and probiotic bacteria. Using flow cytometry, we measured numbers of bacteria binding SIgA and their level of SIgA binding. The percentage of bacteria bound by human and bovine SIgA varied from 30 to 90% depending on bacterial species and strains, but was remarkably consistent between human and bovine SIgA. The level of SIgA binding per bacterial cell was lower for those bacteria that had a higher percentage of SIgA-bound bacteria, and higher for those bacteria that had lower percentage of SIgA-bound bacteria. Overall, human and bovine SIgA interacted with bacteria in a comparable way. This contributes to longer term research about the potential benefits of bovine SIgA for human consumers. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Establishment of Assessment Method for Air Bacteria and Fungi Contamination].

Science.gov (United States)

Zhang, Hua-ling; Yao, Da-jun; Zhang, Yu; Fang, Zi-liang

2016-03-15

In this paper, in order to settle existing problems in the assessment of air bacteria and fungi contamination, the indoor and outdoor air bacteria and fungi filed concentrations by impact method and settlement method in existing documents were collected and analyzed, then the goodness of chi square was used to test whether these concentration data obeyed normal distribution at the significant level of α = 0.05, and combined with the 3σ principle of normal distribution and the current assessment standards, the suggested concentrations ranges of air microbial concentrations were determined. The research results could provide a reference for developing air bacteria and fungi contamination assessment standards in the future.

Investigations of the effect of electron-beam irradiation on bacteria in sewage sludge

International Nuclear Information System (INIS)

Osterstock, G.

1976-01-01

The effect of electron beams on bacteria was investigated in 2 experimental facilities. A 400 kV electron accelerator was used to irradiate sludge quantities of 10 l and 180 l. The total bacterial count, number of coliform bacteria and, in injected sludge, the relative bacteria density of salmonella were investigated. A dose of 0.5 to 0.75 Mrad was required to reduce coliform bacteria to below the detectable level in 0.1 ml. With a dose of 1.5 Mrad salmonella were reduced by 6 orders of magnitude on the average. In addition, the dependence of the reduction in bacteria on the dose rate as well as on mixing of the irradiation material was investigated. Substantial reproduction of bacteria in digested sludge was found in all cases after the irradiation. (author)

Oxidative Stress Parameters in Saliva and Its Association with Periodontal Disease and Types of Bacteria.

Science.gov (United States)

Almerich-Silla, Jose Manuel; Montiel-Company, Jose María; Pastor, Sara; Serrano, Felipe; Puig-Silla, Miriam; Dasí, Francisco

2015-01-01

To determine the association between oxidative stress parameters with periodontal disease, bleeding, and the presence of different periodontal bacteria. A cross-sectional study in a sample of eighty-six patients, divided into three groups depending on their periodontal status. Thirty-three with chronic periodontitis, sixteen with gingivitis, and thirty-seven with periodontal healthy as control. Oxidative stress biomarkers (8-OHdG and MDA), total antioxidant capacity (TAOC), and the activity of two antioxidant enzymes (GPx and SOD) were determined in saliva. Subgingival plaque samples were obtained from the deepest periodontal pocket and PCR was used to determine the presence of the 6 fimA genotypes of Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Tannerella forsythia, and Treponema denticola. Periodontal disease was found to be associated with increased oxidative stress parameter levels. These levels rose according to the number and type of different periodontal bacteria found in the periodontal pockets. The presence of different types of periodontal bacteria is predictive independent variables in linear regresion models of oxidative stress parameters as dependent variable, above all 8-OHdG. Oxidative stress parameter levels are correlated with the presence of different types of bacteria. Determination of these levels and periodontal bacteria could be a potent tool for controlling periodontal disease development.

Antifouling coatings: recent developments in the design of surfaces that prevent fouling by proteins, bacteria, and marine organisms

Energy Technology Data Exchange (ETDEWEB)

Banerjee, Indrani; Pangule, Ravindra C.; Kane, Ravi S. [Howard P. Isermann Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Ricketts Building, Troy, NY 12180 (United States)

2011-02-08

The major strategies for designing surfaces that prevent fouling due to proteins, bacteria, and marine organisms are reviewed. Biofouling is of great concern in numerous applications ranging from biosensors to biomedical implants and devices, and from food packaging to industrial and marine equipment. The two major approaches to combat surface fouling are based on either preventing biofoulants from attaching or degrading them. One of the key strategies for imparting adhesion resistance involves the functionalization of surfaces with poly(ethylene glycol) (PEG) or oligo(ethylene glycol). Several alternatives to PEG-based coatings have also been designed over the past decade. While protein-resistant coatings may also resist bacterial attachment and subsequent biofilm formation, in order to overcome the fouling-mediated risk of bacterial infection it is highly desirable to design coatings that are bactericidal. Traditional techniques involve the design of coatings that release biocidal agents, including antibiotics, quaternary ammonium salts (QAS), and silver, into the surrounding aqueous environment. However, the emergence of antibiotic- and silver-resistant pathogenic strains has necessitated the development of alternative strategies. Therefore, other techniques based on the use of polycations, enzymes, nanomaterials, and photoactive agents are being investigated. With regard to marine antifouling coatings, restrictions on the use of biocide-releasing coatings have made the generation of nontoxic antifouling surfaces more important. While considerable progress has been made in the design of antifouling coatings, ongoing research in this area should result in the development of even better antifouling materials in the future. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Essential knowledge for transistor-level LSI circuit design

CERN Document Server

Nakura, Toru

2016-01-01

This book is a collection of the miscellaneous knowledge essential for transistor-level LSI circuit design, summarized as the issues that need to be considered in each design step. To design an LSI that actually functions and to be able to properly measure it, an extremely large amount of diverse, detailed knowledge is necessary. Even though one may read a textbook about an op-amp, for example, the op-amp circuit design may not actually be possible to complete in one’s CAD tools. The first half of this text explains important design issues such as the operating principles of CAD tools, including schematic entry, SPICE simulation, layout and verification, and RC extraction. Then, mistake-prone topics for many circuit design beginners, resulting from their lack of consideration of these subjects, are explained including IO buffers, noise, and problems due to the progress of miniaturization. Following these topics, basic but very specialized issues for LSI circuit measurement are explained including measuremen...

Occurrence of airborne vancomycin- and gentamicin-resistant bacteria in various hospital wards in Isfahan, Iran.

Science.gov (United States)

Mirhoseini, Seyed Hamed; Nikaeen, Mahnaz; Khanahmad, Hossein; Hassanzadeh, Akbar

2016-01-01

Airborne transmission of pathogenic resistant bacteria is well recognized as an important route for the acquisition of a wide range of nosocomial infections in hospitals. The aim of this study was to determine the prevalence of airborne vancomycin and gentamicin (VM and GM) resistant bacteria in different wards of four educational hospitals. A total of 64 air samples were collected from operating theater (OT), Intensive Care Unit (ICU), surgery ward, and internal medicine ward of four educational hospitals in Isfahan, Iran. Airborne culturable bacteria were collected using all glass impingers. Samples were analyzed for the detection of VM- and GM-resistant bacteria. The average level of bacteria ranged from 99 to 1079 CFU/m(3). The highest level of airborne bacteria was observed in hospital 4 (628 CFU/m(3)) and the highest average concentration of GM- and VM-resistant airborne bacteria were found in hospital 3 (22 CFU/m(3)). The mean concentration of airborne bacteria was the lowest in OT wards and GM- and VM-resistant airborne bacteria were not detected in this ward of hospitals. The highest prevalence of antibiotic-resistant airborne bacteria was observed in ICU ward. There was a statistically significant difference for the prevalence of VM-resistant bacteria between hospital wards (P = 0.012). Our finding showed that the relatively high prevalence of VM- and GM-resistant airborne bacteria in ICUs could be a great concern from the point of view of patients' health. These results confirm the necessity of application of effective control measures which significantly decrease the exposure of high-risk patients to potentially airborne nosocomial infections.

Levels and treatment options for enteric and antibiotic resistant bacteria in sewage from Sisimiut, Greenland

DEFF Research Database (Denmark)

Jensen, Pernille Erland; Gunnarsdottir, Ragnhildur; Andersen, Henrik Rasmus

2013-01-01

Sewage treatment in Arctic towns is inadequate. Sewage contains pathogenic microorganisms, parasites, antibiotic resistant bacteria, and toxic compounds. Discharging of untreated sewage can thus have a negative effect on people’s health and the aquatic environment in the receiving water bodies....... Conventional treatment is challenging and expensive to implement in Arctic communities due to the cold climate and scattered population. In addition, advanced removal of nutrients may in many cases be overstated due to the low population density and large receiving water bodies. In this work we investigated......, the wastewater is very strong, suggesting a potential hygienic risk. In addition, a high fraction of antibiotic resistant bacteria and an increased toxicity in the sub-stream from the hospital, suggest that this stream contains toxic compounds, possibly antibiotic of nature that may affect the local Arctic...

The influence of neonatal intensive care unit design on sound level.

Science.gov (United States)

Chen, Hsin-Li; Chen, Chao-Huei; Wu, Chih-Chao; Huang, Hsiu-Jung; Wang, Teh-Ming; Hsu, Chia-Chi

2009-12-01

Excessive noise in nurseries has been found to cause adverse effects in infants, especially preterm infants in neonatal intensive care units (NICUs). The NICU design may influence the background sound level. We compared the sound level in two differently designed spaces in one NICU. We hypothesized that the sound level in an enclosed space would be quieter than in an open space. Sound levels were measured continuously 24 hours a day in two separate spaces at the same time, one enclosed and one open. Sound-level meters were placed near beds in each room. Sound levels were expressed as decibels, A-weighted (dBA) and presented as hourly L(eq), L(max), L(10), and L(90). The hourly L(eq) in the open space (50.8-57.2dB) was greater than that of the enclosed space (45.9-51.7dB), with a difference of 0.4-10.4dB, and a mean difference of 4.5dB (p<0.0001). The hourly L(10), L(90), and L(max) in the open space also exceeded that in the enclosed space (p<0.0001). The sound level measured in the enclosed space was quieter than in the open space. The design of bed space should be taken into consideration when building a new NICU. Besides the design of NICU architecture, continuous monitoring of sound level in the NICU is important to maintain a quiet environment.

The fecal bacteria

Science.gov (United States)

Sadowsky, Michael J.; Whitman, Richard L.

2011-01-01

The Fecal Bacteria offers a balanced, integrated discussion of fecal bacteria and their presence and ecology in the intestinal tract of mammals, in the environment, and in the food supply. This volume covers their use in examining and assessing water quality in order to offer protection from illnesses related to swimming in or ingesting contaminated water, in addition to discussing their use in engineering considerations of water quality, modeling, monitoring, and regulations. Fecal bacteria are additionally used as indicators of contamination of ready-to-eat foods and fresh produce. The intestinal environment, the microbial community structure of the gut microbiota, and the physiology and genomics of this broad group of microorganisms are explored in the book. With contributions from an internationally recognized group of experts, the book integrates medicine, public health, environmental, and microbiological topics in order to provide a unique, holistic understanding of fecal bacteria. Moreover, it shows how the latest basic science and applied research findings are helping to solve problems and develop effective management strategies. For example, readers will discover how the latest tools and molecular approaches have led to our current understanding of fecal bacteria and enabled us to improve human health and water quality. The Fecal Bacteria is recommended for microbiologists, clinicians, animal scientists, engineers, environmental scientists, food safety experts, water quality managers, and students. It will help them better understand fecal bacteria and use their knowledge to protect human and environmental health. They can also apply many of the techniques and molecular tools discussed in this book to the study of a broad range of microorganisms in a variety of habitats.

Bleach vs. Bacteria

Science.gov (United States)

... Articles | Inside Life Science Home Page Bleach vs. Bacteria By Sharon Reynolds Posted April 2, 2014 Your ... hypochlorous acid to help kill invading microbes, including bacteria. Researchers funded by the National Institutes of Health ...

Cultivation of bacteria with ecological capsules in space

Science.gov (United States)

Sugiura, K.; Hashimoto, H.; Ishikawa, Y.; Kawasaki, Y.; Kobayashi, K.; Seki, K.; Koike, J.; Saito, T.

1999-01-01

A hermetically materially-closed aquatic microcosm containing bacteria, algae, and invertebrates was developed as a tool for determining the changes of ecological systems in space. The species composition was maintained for more than 365 days. The microcosm could be readily replicated. The results obtained from the simulation models indicated that there is a self-regulation homeostasis in coupling of production and consumption, which make the microcosm remarkably stable, and that the transfer of metabolites by diffusion is one of the important factors determining the behavior of the system. The microcosms were continuously irradiated using a 60 Co source. After 80 days, no elimination of organisms was found at any of the three irradiation levels (0.015, 0.55 and 3.0 mGy/day). The number of radio-resistance bacteria mutants was not increased in the microcosm at three irradiation levels. We proposed to research whether this microcosm is self-sustainable in space. When an aquatic ecosystem comes under stress due to the micro-gravity and enhanced radiation environment in space, whether the ecosystem is self-sustainable is not known. An aquatic ecosystem shows what happens as a result of the self-organizational processes of selection and adaptation. A microcosm is a useful tool for understanding such processes. We have proposed researching whether a microcosm is self-sustainable in space. The benefits of this project will be: (1) To acquire data for design of a Controlled Ecological Life Support System, (2) Possibility of microbial mutation in a space station. We report that a hermetically materially-closed microcosm, which could be a useful tool for determining changes of ecological processes in space, was developed, and that the effects of microgravity and enhanced radiation on the hermetically materially-closed microcosm were estimated through measurements on the Earth and simulation models.

Southern routes for high-level radioactive waste: Agencies, contacts, and designations

International Nuclear Information System (INIS)

1991-05-01

The Southern Routes for High-Level Radioactive Waste: Agencies, Contacts and Designations is a compendium of sixteen southern states' routing programs for the transportation of high-level radioactive materials. The report identifies the state-designated routing agencies as defined under 49 Code of Federal Regulations (CFR) Part 171 and provides a reference to the source and scope of the agencies' rulemaking authority. Additionally, the state agency and contact designated by the state's governor to receive advance notification and shipment routing information under 10 CFR Parts 71 and 73 are also listed. This report also examines alternative route designations made by southern states and the lessons that were learned from the designation process

Potential role of bacteria packaging by protozoa in the persistence and transmission of pathogenic bacteria

OpenAIRE

Denoncourt, Alix M.; Paquet, Valérie E.; Charette, Steve J.

2014-01-01

Many pathogenic bacteria live in close association with protozoa. These unicellular eukaryotic microorganisms are ubiquitous in various environments. A number of protozoa such as amoebae and ciliates ingest pathogenic bacteria, package them usually in membrane structures, and then release them into the environment. Packaged bacteria are more resistant to various stresses and are more apt to survive than free bacteria. New evidence indicates that protozoa and not bacteria control the packaging...

The Influence of Neonatal Intensive Care Unit Design on Sound Level

Directory of Open Access Journals (Sweden)

Hsin-Li Chen

2009-12-01

Conclusion: The sound level measured in the enclosed space was quieter than in the open space. The design of bed space should be taken into consideration when building a new NICU. Besides the design of NICU architecture, continuous monitoring of sound level in the NICU is important to maintain a quiet environment.

Reducing COD level on oily effluent by utilizing biosurfactant-producing bacteria

Directory of Open Access Journals (Sweden)

Daniela Franco Carvalho Jacobucci

2009-08-01

Full Text Available Two bacteria isolated from crude oil contaminated soil, Pantoea agglomerans and Planococcus citreus, produced biosurfactants utilizing 1.5% of kerosene and olive oil as the sole carbon sources, respectively. The bacteria and the biosurfactants produced were introduced to oily effluent, arising from margarine and soap industry. Emulsification activities were determined by increases in the absorbance of the oil-in-water emulsions at 610 nm, whereas the water-in-oil emulsions were expressed as the height (cm of the emulsion layers formed. The 72 h incubation experiment resulted in a COD (Chemical Oxygen Demand reduction of 76% with Planococcus citreus strain and 70% with Pantoea agglomerans.The COD reduction with bacterial biosurfactants was over 50% in 24 h of incubation. The COD reduction showed that these strains and the surfactants produced could be used in bioremediation processes.Duas bactérias isoladas de solo contaminado com derivados de petróleo, Pantoea agglomerans e Planococcus citreus, produzem biosurfactantes utilizando respectivamente 1.5% de querosene e óleo de oliva como únicas fontes de carbono. As bactérias e os biosurfactantes produzidos foram adicionados a um efluente oleoso obtido de uma indústria nacional de sabão e margarina. As atividades de emulsificação foram determinadas pelo aumento da absorbância das emulsões óleo em água a 610 nm, enquanto que as emulsões do tipo água em óleo foram expressas em centímetros, pela altura do halo de espumas formado. A redução da demanda química de oxigênio (COD mostra que as linhagens e os biosurfactantes produzidos podem ser utilizados em processos de biorremediação.

Investigations of the effect of electron-beam irradiation on bacteria in sewage sludge

International Nuclear Information System (INIS)

Osterstock, G.

1976-01-01

The effect of electron beams on bacteria was investigated in 2 experimental facilities. A 400 kV electron accelerator was used to irradiate sludge quantities of 10 l and 180 l. The total bacterial count, the number of coliform bacteria and, in injected sludge, the relative bacteria density of salmonella were investigated. A dose of 0.5 to 0.75 Mrad was required to reduce coliform bacteria to below the detectable level in 0.1 ml. With a dose of 1.5 Mrad salmonella were reduced by 6 orders of magnitude on the average. In addition, the dependence of the reduction in bacteria on the dose rate as well as on mixing of the irradiated material was investigated. Substantial reproduction of bacteria in digested sludge was found in all cases after the irradiation. (orig./MG) [de

Expression levels of the receptor activator of NF-κB ligand and osteoprotegerin and the number of gram-negative bacteria in symptomatic and asymptomatic periapical lesions.

Science.gov (United States)

Carneiro, E; Parolin, A B; Wichnieski, C; Rosa, E A R; Silva Neto, U X; Westphalen, V P D; Fariniuk, L F; Johann, A C B R

2017-01-01

The study aimed to verify the potential correlation between the detected amount of gram-negative bacteria and the radiographic sizes of the lesions in patients with symptomatic and asymptomatic apical periodontitis. Furthermore, to evaluate whether the expression of receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG) and the RANKL/OPG ratio are differentially regulated in both groups. Twenty patients with periapical lesions were divided into two groups: symptomatic (SYM) n=10 and asymptomatic (ASYM) n=10. After periapical surgery, the lesions were collected and processed for histological examination, and immunohistochemistry. The percentage of RANKL- and OPG-immunopositive areas relative to the total area of the microscopic field was calculated. For gram staining, the number of gram-negative cells per microscopic field was assessed. The radiographs of each patient were processed and measured. The Student's t-test and the Pearson correlation coefficient were performed. The SYM group showed a significantly higher number of gram-negative cells (p=0.007) when compared to the ASYM group. A higher number of gram-negative bacteria occurred more frequently in larger periapical lesions and the SYM group (p=0.03). The expression for RANKL and OPG and the RANKL/OPG ratio were not significantly different between the groups. There was a significant positive correlation between the number of bacteria and OPG levels in the SYM group (p=0.01). The number of bacteria seems to influence the symptoms and the radiographic size of a periapical lesion. Gram-negative bacteria may play an important role in OPG activity in the SYM group. Copyright © 2016 Elsevier Ltd. All rights reserved.

Bacteria-Mineral Interactions on the Surfaces of Metal-Resistant Bacteria

International Nuclear Information System (INIS)

Malkin, A.J.

2010-01-01

The extraordinary ability of indigenous microorganisms, like metal-resistant bacteria, for biotransformation of toxic compounds is of considerable interest for the emerging area of environmental bioremediation. However, the underlying mechanisms by which metal-resistant bacteria transform toxic compounds are currently unknown and await elucidation. The project's objective was to study stress-induced responses of metal-resistant bacteria to environmental changes and chemical stimulants. This project involved a multi-institutional collaboration of our LLNL group with the group of Dr. H.-Y. Holman (Lawrence Berkeley National Laboratory). In this project, we have utilized metal-resistant bacteria Arthrobacter oxydans as a model bacterial system. We have utilized atomic force microscopy (AFM) to visualize for the first time at the nanometer scale formation of stress-induced structures on bacterial surfaces in response to Cr (VI) exposure. We have demonstrated that structure, assembly, and composition of these stress-induced structures are dependent on Cr (VI) concentrations. Our AFM observations of the appearance and development of stress-induced layers on the surfaces of Arthrobacter oxydans bacteria exposed to Cr (VI) were confirmed by Dr. Holman's biochemical, electron microscopy, and synchrotron infrared spectromicroscopy studies. In general, in vitro imaging of live microbial and cellular systems represents one of the most challenging issues in application of AFM. Various approaches for immobilization of bacteria on the substrate for in vitro imaging were tested in this project. Imaging of live bacteria was achieved, however further optimization of experimental methods are needed for high-resolution visualization of the cellular environmental structural dynamics by AFM. This project enhanced the current insight into molecular architecture, structural and environmental variability of bacterial systems. The project partially funded research for two book chapters (1

PENAMBAHAN BAKTERI ASAM LAKTAT TERENKAPSULASI UNTUK MENEKAN PERTUMBUHAN BAKTERI PATOGEN PADA PROSES PRODUKSI TAPIOKA [Addition of Encapsulated Lactic Acid Bacteria to Suppress the Growth of Pathogenic Bacteria during Tapioca Production

Directory of Open Access Journals (Sweden)

Glisina Dwinoor Rembulan

2015-07-01

Full Text Available Lactic acid bacteria (LAB produce organic acids and active compounds which can inhibit the growth of pathogenic bacteria. Lactic acid bacteria potentially can be introduced to inhibit pathogenic bacteria in the tapioca production at the extraction stage, especially during the settling process since there is possibility of starch slurry to be contaminated by pathogenic bacteria from water. The objectives of this research were to design a solid starter of LAB through encapsulation by using modified starch includes sour cassava starch, lintnerized cassava starch and nanocrystalline starch, utilize the starter for suppressing the growth of pathogenic bacteria in the production process of tapioca and characterize the functional properties of tapioca. The encapsulation of lactic acid bacteria was conducted by freeze drying at a temperature of -50°C for 48 hours. The viability of LAB after freeze drying with sour cassava starch matrix was 92% of the liquid starter, with lintnerized cassava starch matrix was 93%, while that with nanocrystalline matrix was 96%. After application of the LAB culture during settling process for tapioca extraction and the tapioca was stored at room temperature for 6 months, it was shown that E. coli, Salmonella and Shigella were  detected in the native tapioca starch (without treatment while the starch added with lactic acid bacteria starter was not absent for the pathogenic bacteria. The addition of lactic acid bacteria in extraction process can suppress the growth of pathogenic bacteria in tapioca. The results showed that lintnerized cassava starch matrix is the best matrix because after 6 months it still contained lactic acid bacteria as compared to liquid starter and that encapsulated with other matrixes.

Oral, intestinal, and skin bacteria in ventral hernia mesh implants

Directory of Open Access Journals (Sweden)

Odd Langbach

2016-07-01

Full Text Available Background: In ventral hernia surgery, mesh implants are used to reduce recurrence. Infection after mesh implantation can be a problem and rates around 6–10% have been reported. Bacterial colonization of mesh implants in patients without clinical signs of infection has not been thoroughly investigated. Molecular techniques have proven effective in demonstrating bacterial diversity in various environments and are able to identify bacteria on a gene-specific level. Objective: The purpose of this study was to detect bacterial biofilm in mesh implants, analyze its bacterial diversity, and look for possible resemblance with bacterial biofilm from the periodontal pocket. Methods: Thirty patients referred to our hospital for recurrence after former ventral hernia mesh repair, were examined for periodontitis in advance of new surgical hernia repair. Oral examination included periapical radiographs, periodontal probing, and subgingival plaque collection. A piece of mesh (1×1 cm from the abdominal wall was harvested during the new surgical hernia repair and analyzed for bacteria by PCR and 16S rRNA gene sequencing. From patients with positive PCR mesh samples, subgingival plaque samples were analyzed with the same techniques. Results: A great variety of taxa were detected in 20 (66.7% mesh samples, including typical oral commensals and periodontopathogens, enterics, and skin bacteria. Mesh and periodontal bacteria were further analyzed for similarity in 16S rRNA gene sequences. In 17 sequences, the level of resemblance between mesh and subgingival bacterial colonization was 98–100% suggesting, but not proving, a transfer of oral bacteria to the mesh. Conclusion: The results show great bacterial diversity on mesh implants from the anterior abdominal wall including oral commensals and periodontopathogens. Mesh can be reached by bacteria in several ways including hematogenous spread from an oral site. However, other sites such as gut and skin may also

THE SEARCH AND PROPERTIES OF LACTIC ACID BACTERIA PERSPECTIVE FOR BIOTECHNOLOGY

Directory of Open Access Journals (Sweden)

Naumenko О. V.

2014-10-01

Full Text Available Search of biologically active Lactobacillus strains prospective for functional milk food production was the aim of the research. The study involved the lactic acid bacteria isolated from biological material of healthy humen and non- dairy lactic products. Using modern methodological approaches, the strains of lactic acid bacteria such as Lactobacillus casei 302, Lactobacillus acidophilus 35 and Streptococcus thermophilus 21 having high level of biological activity were selected. High biological potential of selected cultures of lactic acid bacteria, which could provide stability for the technological process of production and essential characteristics of bacterial preparations and fermented their products, was set. In vitro the experiments demonstrated that selected strains had valuable production properties, namely the ability to reduce level of cholesterol and lactose during development in milk, were resistant to virulent bacteriophages and aggressive compounds of the gastrointestinal tract, and high adhesive and antagonistic activities as well.

DESIGN ANALYSIS FOR THE DEFENSE HIGH-LEVEL WASTE DISPOSAL CONTAINER

International Nuclear Information System (INIS)

Radulesscu, G.; Tang, J.S.

2000-01-01

The purpose of ''Design Analysis for the Defense High-Level Waste Disposal Container'' analysis is to technically define the defense high-level waste (DHLW) disposal container/waste package using the Waste Package Department's (WPD) design methods, as documented in ''Waste Package Design Methodology Report'' (CRWMS M andO [Civilian Radioactive Waste Management System Management and Operating Contractor] 2000a). The DHLW disposal container is intended for disposal of commercial high-level waste (HLW) and DHLW (including immobilized plutonium waste forms), placed within disposable canisters. The U.S. Department of Energy (DOE)-managed spent nuclear fuel (SNF) in disposable canisters may also be placed in a DHLW disposal container along with HLW forms. The objective of this analysis is to demonstrate that the DHLW disposal container/waste package satisfies the project requirements, as embodied in Defense High Level Waste Disposal Container System Description Document (SDD) (CRWMS M andO 1999a), and additional criteria, as identified in Waste Package Design Sensitivity Report (CRWMS M andQ 2000b, Table 4). The analysis briefly describes the analytical methods appropriate for the design of the DHLW disposal contained waste package, and summarizes the results of the calculations that illustrate the analytical methods. However, the analysis is limited to the calculations selected for the DHLW disposal container in support of the Site Recommendation (SR) (CRWMS M andO 2000b, Section 7). The scope of this analysis is restricted to the design of the codisposal waste package of the Savannah River Site (SRS) DHLW glass canisters and the Training, Research, Isotopes General Atomics (TRIGA) SNF loaded in a short 18-in.-outer diameter (OD) DOE standardized SNF canister. This waste package is representative of the waste packages that consist of the DHLW disposal container, the DHLW/HLW glass canisters, and the DOE-managed SNF in disposable canisters. The intended use of this

DESIGN ANALYSIS FOR THE DEFENSE HIGH-LEVEL WASTE DISPOSAL CONTAINER

Energy Technology Data Exchange (ETDEWEB)

G. Radulesscu; J.S. Tang

2000-06-07

The purpose of ''Design Analysis for the Defense High-Level Waste Disposal Container'' analysis is to technically define the defense high-level waste (DHLW) disposal container/waste package using the Waste Package Department's (WPD) design methods, as documented in ''Waste Package Design Methodology Report'' (CRWMS M&O [Civilian Radioactive Waste Management System Management and Operating Contractor] 2000a). The DHLW disposal container is intended for disposal of commercial high-level waste (HLW) and DHLW (including immobilized plutonium waste forms), placed within disposable canisters. The U.S. Department of Energy (DOE)-managed spent nuclear fuel (SNF) in disposable canisters may also be placed in a DHLW disposal container along with HLW forms. The objective of this analysis is to demonstrate that the DHLW disposal container/waste package satisfies the project requirements, as embodied in Defense High Level Waste Disposal Container System Description Document (SDD) (CRWMS M&O 1999a), and additional criteria, as identified in Waste Package Design Sensitivity Report (CRWMS M&Q 2000b, Table 4). The analysis briefly describes the analytical methods appropriate for the design of the DHLW disposal contained waste package, and summarizes the results of the calculations that illustrate the analytical methods. However, the analysis is limited to the calculations selected for the DHLW disposal container in support of the Site Recommendation (SR) (CRWMS M&O 2000b, Section 7). The scope of this analysis is restricted to the design of the codisposal waste package of the Savannah River Site (SRS) DHLW glass canisters and the Training, Research, Isotopes General Atomics (TRIGA) SNF loaded in a short 18-in.-outer diameter (OD) DOE standardized SNF canister. This waste package is representative of the waste packages that consist of the DHLW disposal container, the DHLW/HLW glass canisters, and the DOE-managed SNF in disposable

Antimicrobial Photodynamic Therapy to Kill Gram-negative Bacteria

Science.gov (United States)

Sperandio, Felipe F; Huang, Ying-Ying; Hamblin, Michael R

2013-01-01

Antimicrobial photodynamic therapy (PDT) or photodynamic inactivation (PDI) is a new promising strategy to eradicate pathogenic microorganisms such as Gram-positive and Gram-negative bacteria, yeasts and fungi. The search for new approaches that can kill bacteria but do not induce the appearance of undesired drug-resistant strains suggests that PDT may have advantages over traditional antibiotic therapy. PDT is a non-thermal photochemical reaction that involves the simultaneous presence of visible light, oxygen and a dye or photosensitizer (PS). Several PS have been studied for their ability to bind to bacteria and efficiently generate reactive oxygen species (ROS) upon photostimulation. ROS are formed through type I or II mechanisms and may inactivate several classes of microbial cells including Gram-negative bacteria such as Pseudomonas aeruginosa, which are typically characterized by an impermeable outer cell membrane that contains endotoxins and blocks antibiotics, dyes, and detergents, protecting the sensitive inner membrane and cell wall. This review covers significant peer-reviewed articles together with US and World patents that were filed within the past few years and that relate to the eradication of Gram-negative bacteria via PDI or PDT. It is organized mainly according to the nature of the PS involved and includes natural or synthetic food dyes; cationic dyes such as methylene blue and toluidine blue; tetrapyrrole derivatives such as phthalocyanines, chlorins, porphyrins, chlorophyll and bacteriochlorophyll derivatives; functionalized fullerenes; nanoparticles combined with different PS; other formulations designed to target PS to bacteria; photoactive materials and surfaces; conjugates between PS and polycationic polymers or antibodies; and permeabilizing agents such as EDTA, PMNP and CaCl2. The present review also covers the different laboratory animal models normally used to treat Gram-negative bacterial infections with antimicrobial PDT. PMID

Lactic acid bacteria as a cell factory for riboflavin production.

Science.gov (United States)

Thakur, Kiran; Tomar, Sudhir Kumar; De, Sachinandan

2016-07-01

Consumers are increasingly becoming aware of their health and nutritional requirements, and in this context, vitamins produced in situ by microbes may suit their needs and expectations. B groups vitamins are essential components of cellular metabolism and among them riboflavin is one of the vital vitamins required by bacteria, plants, animals and humans. Here, we focus on the importance of microbial production of riboflavin over chemical synthesis. In addition, genetic abilities for riboflavin biosynthesis by lactic acid bacteria are discussed. Genetically modified strains by employing genetic engineering and chemical analogues have been developed to enhance riboflavin production. The present review attempts to collect the currently available information on riboflavin production by microbes in general, while placing greater emphasis on food grade lactic acid bacteria and human gut commensals. For designing riboflavin-enriched functional foods, proper selection and exploitation of riboflavin-producing lactic acid bacteria is essential. Moreover, eliminating the in situ vitamin fortification step will decrease the cost of food production. © 2015 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Anaerobic bacteria in wastewater treatment plant.

Science.gov (United States)

Cyprowski, Marcin; Stobnicka-Kupiec, Agata; Ławniczek-Wałczyk, Anna; Bakal-Kijek, Aleksandra; Gołofit-Szymczak, Małgorzata; Górny, Rafał L

2018-03-28

The objective of this study was to assess exposure to anaerobic bacteria released into air from sewage and sludge at workplaces from a wastewater treatment plant (WWTP). Samples of both sewage and sludge were collected at six sampling points and bioaerosol samples were additionally collected (with the use of a 6-stage Andersen impactor) at ten workplaces covering different stages of the technological process. Qualitative identification of all isolated strains was performed using the biochemical API 20A test. Additionally, the determination of Clostridium pathogens was carried out using 16S rRNA gene sequence analysis. The average concentration of anaerobic bacteria in the sewage samples was 5.49 × 10 4 CFU/mL (GSD = 85.4) and in sludge-1.42 × 10 6 CFU/g (GSD = 5.1). In turn, the average airborne bacterial concentration was at the level of 50 CFU/m 3 (GSD = 5.83) and the highest bacterial contamination (4.06 × 10 3  CFU/m 3 ) was found in winter at the bar screens. In total, 16 bacterial species were determined, from which the predominant strains belonged to Actinomyces, Bifidobacterium, Clostridium, Propionibacterium and Peptostreptococcus genera. The analysis revealed that mechanical treatment processes were responsible for a substantial emission of anaerobic bacteria into the air. In both the sewage and air samples, Clostridium perfringens pathogen was identified. Anaerobic bacteria were widely present both in the sewage and in the air at workplaces from the WWTP, especially when the technological process was performed in closed spaces. Anaerobic bacteria formed small aggregates with both wastewater droplets and dust particles of sewage sludge origin and as such may be responsible for adverse health outcomes in exposed workers.

Phylogeny of the ammonia-producing ruminal bacteria Peptostreptococcus anaerobius, Clostridium sticklandii, and Clostridium aminophilum sp. nov

Science.gov (United States)

Paster, B. J.; Russell, J. B.; Yang, C. M.; Chow, J. M.; Woese, C. R.; Tanner, R.

1993-01-01

In previous studies, gram-positive bacteria which grew rapidly with peptides or an amino acid as the sole energy source were isolated from bovine rumina. Three isolates, strains C, FT (T = type strain), and SR, were considered to be ecologically important since they produced up to 20-fold more ammonia than other ammonia-producing ruminal bacteria. On the basis of phenotypic criteria, the taxonomic position of these new isolates was uncertain. In this study, the 16S rRNA sequences of these isolates and related bacteria were determined to establish the phylogenetic positions of the organisms. The sequences of strains C, FT, and SR and reference strains of Peptostreptococcus anaerobius, Clostridium sticklandii, Clostridium coccoides, Clostridium aminovalericum, Acetomaculum ruminis, Clostridium leptum, Clostridium lituseburense, Clostridium acidiurici, and Clostridium barkeri were determined by using a modified Sanger dideoxy chain termination method. Strain C, a large coccus purported to belong to the genus Peptostreptococcus, was closely related to P. anaerobius, with a level of sequence similarity of 99.6%. Strain SR, a heat-resistant, short, rod-shaped organism, was closely related to C. sticklandii, with a level of sequence similarity of 99.9%. However, strain FT, a heat-resistant, pleomorphic, rod-shaped organism, was only distantly related to some clostridial species and P. anaerobius. On the basis of the sequence data, it was clear that strain FT warranted designation as a separate species. The closest known relative of strain FT was C. coccoides (level of similarity, only 90.6%). Additional strains that are phenotypically similar to strain FT were isolated in this study.(ABSTRACT TRUNCATED AT 250 WORDS).

Preferential aerosolization of bacteria in bioaerosols generated in vitro.

Science.gov (United States)

Perrott, P; Turgeon, N; Gauthier-Levesque, L; Duchaine, C

2017-09-01

Little is known about how bacteria are aerosolized in terms of whether some bacteria will be found in the air more readily than others that are present in the source. This report describes in vitro experiments to compare aerosolization rates (also known as preferential aerosolization) of Gram-positive and Gram-negative bacteria as well as rod- and coccus-shaped bacteria, using two nebulization conditions. A consortium of five bacterial species was aerosolized in a homemade chamber. Aerosols generated with a commercial nebulizer and a homemade bubble-burst aerosol generator were compared. Data suggest that Pseudomonas aeruginosa was preferentially aerosolized in comparison to Moraxella catarrhalis, Lactobacillus paracasei, Staphylococcus aureus and Streptococcus suis, independently of the method of aerosolization. Bacterial integrity of Strep. suis was more preserved compared to other bacteria studied as revealed with PMA-qPCR. We reported the design of an aerosol chamber and bubble-burst generator for the in vitro study of preferential aerosolization. In our setting, preferential aerosolization was influenced by bacterial properties instead of aerosolization mechanism. These findings could have important implications for predicting the composition of bioaerosols in various locations such as wastewater treatment plants, agricultural settings and health care settings. © 2017 The Society for Applied Microbiology.

Design features of a full-scale high-level waste vitrification system

International Nuclear Information System (INIS)

Siemens, D.H.; Bonner, W.F.

1976-08-01

A system has been designed and is currently under construction for vitrification of commercial high-level waste. The process consists of a spray calciner coupled to an in-can melter. Due to the high radiation levels expected, this equipment is designed for totally remote operation and maintenance. The in-cell arrangement of this equipment has been developed cooperatively with a nuclear fuel reprocessor. The system will be demonstrated both full scale with nonradioactive simulated waste and pilot scale with actual high-level waste

Does Social Capital Explain Community-Level Differences in Organ Donor Designation?

Science.gov (United States)

Ladin, Keren; Wang, Rui; Fleishman, Aaron; Boger, Matthew; Rodrigue, James R

2015-09-01

The growing shortage of life-saving organs has reached unprecedented levels, with more than 120,000 Americans waiting for them. Despite national attempts to increase organ donation and federal laws mandating the equitable allocation of organs, geographic disparities remain. A better understanding of the contextual determinants of organ donor designation, including social capital, may enhance efforts to increase organ donation by raising the probability of collective action and fostering norms of reciprocity and cooperation while increasing costs to defectors. Because community-level factors, including social capital, predict more than half the variation in donor designation, future interventions should tailor strategies to specific communities as the unit of intervention. The growing shortage of organs has reached unprecedented levels. Despite national attempts to increase donation and federal laws mandating the equitable allocation of organs, their availability and waiting times vary significantly nationwide. Organ donor designation is a collective action problem in public health, in which the regional organ supply and average waiting times are determined by the willingness of individuals to be listed as organ donors. Social capital increases the probability of collective action by fostering norms of reciprocity and cooperation while increasing costs to defectors. We examine whether social capital and other community-level factors explain geographic variation in organ donor designation rates in Massachusetts. We obtained a sample of 3,281,532 registered drivers in 2010 from the Massachusetts Department of Transportation Registry of Motor Vehicles (MassDOT RMV). We then geocoded the registry data, matched them to 4,466 census blocks, and linked them to the 2010 US Census, the American Community Survey (ACS), and other sources to obtain community-level sociodemographic, social capital (residential segregation, voter registration and participation, residential

Quantification of syntrophic fatty acid-{beta}-oxidizing bacteria in a mesophilic biogas reactor by oligonucleotide probe hybridization

Energy Technology Data Exchange (ETDEWEB)

Hansen, K.H.; Ahring, B.K.; Raskin, L.

1999-11-01

Small-subunit rRNA sequences were obtained for two saturated fatty acid-{beta}-oxidizing syntrophic bacteria, Syntrophomonas sapovorans and Syntrophomonas wolfei LYB, and sequence analysis confirmed their classification as members of the family Syntrophomonadaceae. S.wolfei LYB was closely related to S.wolfei subsp. solfei, but S. sapovorans did not cluster with the other members of the genus Syntrophomonas. Five oligonucleotide probes targeting the small-subunit rRNA of different groups within the family Syntrophomonadaceae, which contains all currently known saturated fatty acid-{beta}-oxidizing syntrophic bacteria, were developed and characterized. The probes were designed to be specific at the family, genus, and species levels and were characterized by temperature-of-dissociation and specificity studies. To demonstrate the usefulness of the probes for the detection and quantification of saturated fatty acid-{beta}-oxidizing syntrophic bacteria in methanogenic environments, the microbial community structure of a sample from a full-scale biogas plant was determined. Hybridization results with probes for syntrophic bacteria and methanogens were compared to specific methanogenic activities and microbial numbers determined with most-probable-number estimates. Most of the methanogenic rRNA was comprised of Methanomicrobiales rRNA, suggesting that members of this order served as the main hydrogen-utilizing microorganisms. Between 0.2 and 1% of the rRNA was attributed to the Syntrophomonadaceae, or which the majority was accounted for by the genus Syntrophomonas.

Zonulin Regulates Intestinal Permeability and Facilitates Enteric Bacteria Permeation in Coronary Artery Disease.

Science.gov (United States)

Li, Chuanwei; Gao, Min; Zhang, Wen; Chen, Caiyu; Zhou, Faying; Hu, Zhangxu; Zeng, Chunyu

2016-06-29

Several studies have reported an association between enteric bacteria and atherosclerosis. Bacterial 16S ribosomal RNA (rRNA) gene belong to Enterobacteriaceae have been detected in atherosclerotic plaques. How intestinal bacteria go into blood is not known. Zonulin reversibly modulate intestinal permeability (IP), the circulating zonulin levels were increased in diabetes, obesity, all of which are risk factors for atherosclerosis. It is unclear whether the circulating zonulin levels were changed in coronary artery disease (CAD) patients and modulate IP. The 16S rRNA gene of bacteria in blood sample was checked by 454 pyrosequencing. The zonulin levels were determined by enzyme-linked immunosorbent assay (ELISA) methods. The distribution of zonulin was detected by confocal immunofluorescence microscopy. Bacteria and Caco-2 cell surface micro-structure were checked by transmission electron microscopy. A high diversity of bacterial 16S rRNA gene can be detected in samples from CAD patients, most of them (99.4%) belong to Enterobacteriaceaes, eg. Rahnella. The plasma zonulin levels were significantly higher in CAD patients. Pseudomonas fluorescens exposure significantly increased zonulin expression and decreased IP in a time dependent manner. The elevated zonulin increase IP and may facilitate enteric translocation by disassembling the tight junctions, which might explain the observed high diversity of bacterial 16S rRNA genes in blood samples.

Remediation of Acid Mine Drainage with Sulfate Reducing Bacteria

Science.gov (United States)

Hauri, James F.; Schaider, Laurel A.

2009-01-01

Sulfate reducing bacteria have been shown to be effective at treating acid mine drainage through sulfide production and subsequent precipitation of metal sulfides. In this laboratory experiment for undergraduate environmental chemistry courses, students design and implement a set of bioreactors to remediate acid mine drainage and explain observed…

Isolation and characterization of bacteria from wasted ionic exchange resins kept at Area de Gestion Ezeiza belonging to RA-3 Reactor

International Nuclear Information System (INIS)

Mosquera Rodriguez, Leon; Pizarro, Ramon A.

2009-01-01

A spent ionic exchange resin kept at Area de Gannet's Ezeiza (Age), belonging to RA-3 Reactor, was treated with sterile water. Microorganisms suspended in the aqueous sample were isolated by several methods, broadening as much as possible cell recovery conditions. Bacteria were subject to purity controls and re-isolation when necessary. Characterization of the strains found in the sample included morphological, physiological and biochemical tests as well as stains. Being the spent resins volume reduction at Age the main purpose, a screening experiment is proposed based on bacteria capability to take carbon from the sediment present in the liquid sample. Recovered bacteria are at least the following: Method I: Bacillus cereus, Bacillus circulans, Bacillus sp., Pseudomonas pseudoalcaligenes, Pseudomonas acidovorans, Pseudomonas sp. Method II: Bacillus cereus, Pseudomonas alcaligenes, Flavimonas sp., Agrobacterium sp. Method III: Bacillus circulans, Bacillus sphaericus, Kocuria rosea, Kytococcus sedentarius, Pseudomonas acidovorans. Microorganisms present in the sample are characteristic of those having low microbiological-contamination levels. Way III is an isolation method whose design would lead to find bacteria having the desired properties in order to diminish the volume of RA-3 Reactor spent resins. (author)

Potential role of bacteria packaging by protozoa in the persistence and transmission of pathogenic bacteria

Directory of Open Access Journals (Sweden)

Alix M Denoncourt

2014-05-01

Full Text Available Many pathogenic bacteria live in close association with protozoa. These unicellular eukaryotic microorganisms are ubiquitous in various environments. A number of protozoa such as amoebae and ciliates ingest pathogenic bacteria, package them usually in membrane structures, and then release them into the environment. Packaged bacteria are more resistant to various stresses and are more apt to survive than free bacteria. New evidence indicates that protozoa and not bacteria control the packaging process. It is possible that packaging is more common than suspected and may play a major role in the persistence and transmission of pathogenic bacteria. To confirm the role of packaging in the propagation of infections, it is vital that the molecular mechanisms governing the packaging of bacteria by protozoa be identified as well as elements related to the ecology of this process in order to determine whether packaging acts as a Trojan Horse.

Effect of whey fermented by Enterococcus faeciumin consortium with Veilonella parvulaon ruminal bacteria in vitro

Directory of Open Access Journals (Sweden)

Higor Fábio Carvalho Bezerra

2014-05-01

Full Text Available The objective of this research was to evaluate the effect of whey fermented by Enterococus faecium in consortium with Veilonella parvula in vitro on ruminal microorganisms in different substrates, with or without monensin. The first experiment was carried out in a completely randomized design, in a 6 × 3 factorial arrangement (six substrates × three whey levels with two replicates. In experiment two, a 2 × 3 × 4 factorial arrangement (with and without monensin, three foods and four levels of fermented whey was used, in a randomized design with four replicates, totaling 24 treatments. There was no interaction among the wheys and the substrates in the variable for pectin, starch, and carboxymethyl cellulose. There was a greater growth of amylolytic and pectinolytic microorganisms and a lower growth of proteolytic and cellulolytic microorganisms. A significant effect of optical density was found in the media without substrate and that containing trypticase and glucose due to the addition of fermented whey. There was interaction for the pH at 24 hours among whey, food and monensin. For ammonia at 24 hours there was effect for food, whey and monensin, and interaction among factors. For microbial protein at 24 hours, there was effect for food, whey, monensin and no interaction among sources of variation. The use of whey fermented by bacteria Enterococcus faeciumand Veilonella parvula improves microbial protein synthesis by ruminal bacteria in media containing different energy sources. The combination of fermented whey and monensin shows variable results in relation to microbial growth.

Rapid Separation of Bacteria from Blood—Review and Outlook

Science.gov (United States)

Alizadeh, Mahsa; Husseini, Ghaleb A.; McClellan, Daniel S.; Buchanan, Clara M.; Bledsoe, Colin G.; Robison, Richard A.; Blanco, Rae; Roeder, Beverly L.; Melville, Madison; Hunter, Alex K.

2017-01-01

The high morbidity and mortality rate of bloodstream infections involving antibiotic-resistant bacteria necessitate a rapid identification of the infectious organism and its resistance profile. Traditional methods based on culturing the blood typically require at least 24 h, and genetic amplification by PCR in the presence of blood components has been problematic. The rapid separation of bacteria from blood would facilitate their genetic identification by PCR or other methods so that the proper antibiotic regimen can quickly be selected for the septic patient. Microfluidic systems that separate bacteria from whole blood have been developed, but these are designed to process only microliter quantities of whole blood or only highly diluted blood. However, symptoms of clinical blood infections can be manifest with bacterial burdens perhaps as low as 10 CFU/mL, and thus milliliter quantities of blood must be processed to collect enough bacteria for reliable genetic analysis. This review considers the advantages and shortcomings of various methods to separate bacteria from blood, with emphasis on techniques that can be done in less than 10 min on milliliter-quantities of whole blood. These techniques include filtration, screening, centrifugation, sedimentation, hydrodynamic focusing, chemical capture on surfaces or beads, field-flow fractionation, and dielectrophoresis. Techniques with the most promise include screening, sedimentation, and magnetic bead capture, as they allow large quantities of blood to be processed quickly. Some microfluidic techniques can be scaled up. PMID:27160415

Lipopolysaccharides in diazotrophic bacteria.

Science.gov (United States)

Serrato, Rodrigo V

2014-01-01

Biological nitrogen fixation (BNF) is a process in which the atmospheric nitrogen (N2) is transformed into ammonia (NH3) by a select group of nitrogen-fixing organisms, or diazotrophic bacteria. In order to furnish the biologically useful nitrogen to plants, these bacteria must be in constant molecular communication with their host plants. Some of these molecular plant-microbe interactions are very specific, resulting in a symbiotic relationship between the diazotroph and the host. Others are found between associative diazotrophs and plants, resulting in plant infection and colonization of internal tissues. Independent of the type of ecological interaction, glycans, and glycoconjugates produced by these bacteria play an important role in the molecular communication prior and during colonization. Even though exopolysaccharides (EPS) and lipochitooligosaccharides (LCO) produced by diazotrophic bacteria and released onto the environment have their importance in the microbe-plant interaction, it is the lipopolysaccharides (LPS), anchored on the external membrane of these bacteria, that mediates the direct contact of the diazotroph with the host cells. These molecules are extremely variable among the several species of nitrogen fixing-bacteria, and there are evidences of the mechanisms of infection being closely related to their structure.

Cable Bacteria in Freshwater Sediments

DEFF Research Database (Denmark)

Risgaard-Petersen, Nils; Kristiansen, Michael; Frederiksen, Rasmus

2015-01-01

In marine sediments cathodic oxygen reduction at the sediment surface can be coupled to anodic sulfide oxidation in deeper anoxic layers through electrical currents mediated by filamentous, multicellular bacteria of the Desulfobulbaceae family, the so-called cable bacteria. Until now, cable...... bacteria have only been reported from marine environments. In this study, we demonstrate that cable bacteria also occur in freshwater sediments. In a first step, homogenized sediment collected from the freshwater stream Giber Å, Denmark, was incubated in the laboratory. After 2 weeks, pH signatures...... marine cable bacteria, with the genus Desulfobulbus as the closest cultured lineage. The results of the present study indicate that electric currents mediated by cable bacteria could be important for the biogeochemistry in many more environments than anticipated thus far and suggest a common evolutionary...

Solving bi-level optimization problems in engineering design using kriging models

Science.gov (United States)

Xia, Yi; Liu, Xiaojie; Du, Gang

2018-05-01

Stackelberg game-theoretic approaches are applied extensively in engineering design to handle distributed collaboration decisions. Bi-level genetic algorithms (BLGAs) and response surfaces have been used to solve the corresponding bi-level programming models. However, the computational costs for BLGAs often increase rapidly with the complexity of lower-level programs, and optimal solution functions sometimes cannot be approximated by response surfaces. This article proposes a new method, namely the optimal solution function approximation by kriging model (OSFAKM), in which kriging models are used to approximate the optimal solution functions. A detailed example demonstrates that OSFAKM can obtain better solutions than BLGAs and response surface-based methods, and at the same time reduce the workload of computation remarkably. Five benchmark problems and a case study of the optimal design of a thin-walled pressure vessel are also presented to illustrate the feasibility and potential of the proposed method for bi-level optimization in engineering design.

Azolla-anabaena-bacteria system as a natural microcosm

Science.gov (United States)

Carrapico, Francisco J.

2002-02-01

Azolla is an aquatic fern that contains a permanent endosymbiotic prokaryotic community (cyanobacteria and bacteria) inside of the cavity in the leaf dorsal lobe of the pteridophyte. This is a unique situation and can be seen as a microcosm inside of an organism and also can be considered a good example of a living model for biological and environmental studies. These symbionts are specific of this symbiosis and lives immobilized in a mucilaginous fibrillar network, which fills part of the cavity. The symbionts works as immobilized organisms in a natural system that can be used as a model for biotechnological research and in biologically based life support systems. The nature and the complexity of this system is simultaneously a reference and a challenge for the research in the communication between the two levels of nature organization (microcosm and mesocosm), and can also be used as a reference for the design of new environmental engineered symbiotic systems that include man as a prelude to life in space.

Oxidative Damage Caused by Common Foodborne Pathogenic Bacteria in Egg Yolk

Directory of Open Access Journals (Sweden)

Reyhaneh Afshordi

2016-02-01

Full Text Available Background: Bacteria in foodstuff are the most important agent of foodborne disease. Aside from their infectious effects, obligate aerobes have a respiratory metabolism with oxygen as the terminal electron acceptor. Therefore, they can produce reactive oxygen species and free radicals in contaminated food. Malondialdehyde (MDA is a product of lipid peroxidation used as an indicator of oxidative stress. Objectives: This study aimed to evaluate the oxidative damage produced by two common food pathogenic bacteria in foodstuff. Materials and Methods: The egg yolks were incubated with different dilutions (105,106, and 107 of Staphylococcus aureus and Salmonella enteritidis at 37°C for 20 hours. The level of MDA in egg yolk was measured by fast and simple enzymatic or colorimetric methods, such as the thiobarbituric acid reactive species method. Results: The high group (107 had a higher MDA level of 1.97 ± 0.11 (μg MDA/g in S. aureus and 1.65 ± 0.27 (mg MDA/L in S. enteritidis than the control (0.90 ± 0.13 mg MDA/L. Conclusions: We concluded that common food pathogenic bacteria can induce oxidative damage in foodstuff aside from other common problems. Heating or sterilization methods cannot protect foodstuff from the damage caused by the presence of pathogenic bacteria.

Gravity separation of fat, somatic cells, and bacteria in raw and pasteurized milks.

Science.gov (United States)

Caplan, Z; Melilli, C; Barbano, D M

2013-04-01

The objective of experiment 1 was to determine if the extent of gravity separation of milk fat, bacteria, and somatic cells is influenced by the time and temperature of gravity separation or the level of contaminating bacteria present in the raw milk. The objective of experiment 2 was to determine if different temperatures of milk heat treatment affected the gravity separation of milk fat, bacteria, and somatic cells. In raw milk, fat, bacteria, and somatic cells rose to the top of columns during gravity separation. About 50 to 80% of the fat and bacteria were present in the top 8% of the milk after gravity separation of raw milk. Gravity separation for 7h at 12°C or for 22h at 4°C produced equivalent separation of fat, bacteria, and somatic cells. The completeness of gravity separation of fat was influenced by the level of bacteria in the milk before separation. Milk with a high bacterial count had less (about 50 to 55%) gravity separation of fat than milk with low bacteria count (about 80%) in 22h at 4°C. Gravity separation caused fat, bacteria, and somatic cells to rise to the top of columns for raw whole milk and high temperature, short-time pasteurized (72.6°C, 25s) whole milk. Pasteurization at ≥76.9°C for 25s prevented all 3 components from rising, possibly due to denaturation of native bovine immunoglobulins that normally associate with fat, bacteria, and somatic cells during gravity separation. Gravity separation can be used to produce reduced-fat milk with decreased bacterial and somatic cell counts, and may be a critical factor in the history of safe and unique traditional Italian hard cheeses produced from gravity-separated raw milk. A better understanding of the mechanism of this natural process could lead to the development of new nonthermal thermal technology (that does not involve heating the milk to high temperatures) to remove bacteria and spores from milk or other liquids. Copyright © 2013 American Dairy Science Association. Published by

Risk-informed design of IRIS using a level-1 probabilistic risk assessment from its conceptual design phase

International Nuclear Information System (INIS)

Mizuno, Yuko; Ninokata, Hisashi; Finnicum, David J.

2005-01-01

In this study, a probabilistic risk assessment (PRA) for the International Reactor Innovative and Secure (IRIS) has been generated to address two key areas as a part of the effort for the pre-application licensing of the IRIS design. First, the IRIS PRA is supporting the evaluation of IRIS design by providing design insights as well as a solid risk basis for the pre-licensing evaluation of the IRIS design. Second, the current PRA task is beginning the preparation of the more complete PRA analyses and documentation that will be required for Design Certification. The initial IRIS PRA is an at-power, Level-1 PRA for internal events that focuses on the evaluation of the IRIS design features to support the risk-informed design of IRIS by application of the PRA insights and the risk information to the design. To accomplish the evaluation, a reasonably complete Level-1 PRA model has been developed. The use of PRA in the early stages of the design has allowed a selection of design and performance features and an optimization of the design of several systems to reduce the potential for events that could lead to core damage via both enhanced prevention and mitigation of challenges. As a result, the total core damage frequency for internal events for the IRIS design has been calculated as 1.2x10 -8 per year

Metabolic and process engineering for biodesulfurization in Gram-negative bacteria.

Science.gov (United States)

Martínez, I; El-Said Mohamed, M; Santos, V E; García, J L; García-Ochoa, F; Díaz, E

2017-11-20

Microbial desulfurization or biodesulfurization (BDS) is an attractive low-cost and environmentally friendly complementary technology to the hydrotreating chemical process based on the potential of certain bacteria to specifically remove sulfur from S-heterocyclic compounds of crude fuels that are recalcitrant to the chemical treatments. The 4S or Dsz sulfur specific pathway for dibenzothiophene (DBT) and alkyl-substituted DBTs, widely used as model S-heterocyclic compounds, has been extensively studied at the physiological, biochemical and genetic levels mainly in Gram-positive bacteria. Nevertheless, several Gram-negative bacteria have been also used in BDS because they are endowed with some properties, e.g., broad metabolic versatility and easy genetic and genomic manipulation, that make them suitable chassis for systems metabolic engineering strategies. A high number of recombinant bacteria, many of which are Pseudomonas strains, have been constructed to overcome the major bottlenecks of the desulfurization process, i.e., expression of the dsz operon, activity of the Dsz enzymes, retro-inhibition of the Dsz pathway, availability of reducing power, uptake-secretion of substrate and intermediates, tolerance to organic solvents and metals, and other host-specific limitations. However, to attain a BDS process with industrial applicability, it is necessary to apply all the knowledge and advances achieved at the genetic and metabolic levels to the process engineering level, i.e., kinetic modelling, scale-up of biphasic systems, enhancing mass transfer rates, biocatalyst separation, etc. The production of high-added value products derived from the organosulfur material present in oil can be regarded also as an economically viable process that has barely begun to be explored. Copyright © 2017 Elsevier B.V. All rights reserved.

Bacteria in non-woven textile filters for domestic wastewater treatment.

Science.gov (United States)

Spychała, Marcin; Starzyk, Justyna

2015-01-01

The objective of this study was preliminary identification of heterotrophic and ammonia oxidizing bacteria (AOB) cell concentration in the cross-sectional profile of geotextile filters for wastewater treatment. Filters of thicknesses 3.6 and 7.2 mm, made of non-woven textile TS20, were supplied with septic tank effluent and intermittently dosed and filtered under hydrostatic pressure. The cumulative loads of chemical oxygen demand (COD) and total solids were about 1.36 and 1.06 kg/cm2, respectively. The filters under analysis reached a relatively high removal efficiency for organic pollution 70-90% for biochemical oxygen demand (BOD5) and 60-85% for COD. The ammonia nitrogen removal efficiency level proved to be unstable (15-55%). Biomass samples for dry mass identification were taken from two regions: continuously flooded with wastewater and intermittently flooded with wastewater. The culturable heterotrophic bacteria were determined as colony-forming units (CFUs) on microbiological-selective media by means of the plate method. AOB and nitrite oxidizing bacteria (NOB) were examined using the FISH technique. A relatively wide range of heterotrophic bacteria was observed from 7.4×10(5)/cm2 to 3.8×10(6)/cm2 in geotextile layers. The highest concentration of heterotrophic bacteria (3.8×10(6)/cm2) was observed in the first layer of the textile filter. AOB were identified occasionally--about 8-15% of all bacteria colonizing the last filter layer, but occasionally much higher concentrations and ammonia nitrogen efficiency were achieved. Bacteria oxidizing nitrite to nitrate were not observed. The relation of total and organic fraction of biomass to culturable heterotrophic bacteria was also found.

[Metabolism of carbohydrates in the cells of green sulphur bacteria Chlorobium limicola Ya-2002].

Science.gov (United States)

Horishnyĭ, M B; Hudz', S P; Hnatush, S O

2009-01-01

The nature of carbohydrates that accumulate in the cells of photosynthetic green sulphur bacteria of Chlorobium limicola Ya-2002 has been investigated. It is shown by infra-red spectrometry, that carbohydrates accumulated in the cells of bacteria are identical (by 90-95%) to glycogen of the bull liver. Exogenous glucose, saccharose, maltose, did not stimulate formation of glycogen. Growth of glycogen level in the cells of bacteria was observed at addition of acetate or piruvate in the conditions of bacteria cultivation in the light and in the presence CO2 and H2S in the environment. Washed cells of C. limicola Ya-2002 did not use glucose of the environment neither in the conditions of illumination nor in darkness, however acetate and piruvate are actively used in the light. During incubation of the washed cells in darkness the level of glycogen fell down approximately three times. Its amount during cells incubation in the light did not change. The decline of glycogen level in cells during their incubation in darkness was accompanied by piling up of carbonic acids in the environment acetate prevailing among them.

Molecular identification of potential denitrifying bacteria and use of D-optimal mixture experimental design for the optimization of denitrification process.

Science.gov (United States)

Ben Taheur, Fadia; Fdhila, Kais; Elabed, Hamouda; Bouguerra, Amel; Kouidhi, Bochra; Bakhrouf, Amina; Chaieb, Kamel

2016-04-01

Three bacterial strains (TE1, TD3 and FB2) were isolated from date palm (degla), pistachio and barley. The presence of nitrate reductase (narG) and nitrite reductase (nirS and nirK) genes in the selected strains was detected by PCR technique. Molecular identification based on 16S rDNA sequencing method was applied to identify positive strains. In addition, the D-optimal mixture experimental design was used to optimize the optimal formulation of probiotic bacteria for denitrification process. Strains harboring denitrification genes were identified as: TE1, Agrococcus sp LN828197; TD3, Cronobacter sakazakii LN828198 and FB2, Pedicoccus pentosaceus LN828199. PCR results revealed that all strains carried the nirS gene. However only C. sakazakii LN828198 and Agrococcus sp LN828197 harbored the nirK and the narG genes respectively. Moreover, the studied bacteria were able to form biofilm on abiotic surfaces with different degree. Process optimization showed that the most significant reduction of nitrate was 100% with 14.98% of COD consumption and 5.57 mg/l nitrite accumulation. Meanwhile, the response values were optimized and showed that the most optimal combination was 78.79% of C. sakazakii LN828198 (curve value), 21.21% of P. pentosaceus LN828199 (curve value) and absence (0%) of Agrococcus sp LN828197 (curve value). Copyright © 2016 Elsevier Ltd. All rights reserved.

Arsenite-oxidizing and arsenate-reducing bacteria associated with arsenic-rich groundwater in Taiwan

Science.gov (United States)

Liao, Vivian Hsiu-Chuan; Chu, Yu-Ju; Su, Yu-Chen; Hsiao, Sung-Yun; Wei, Chia-Cheng; Liu, Chen-Wuing; Liao, Chung-Min; Shen, Wei-Chiang; Chang, Fi-John

2011-04-01

Drinking highly arsenic-contaminated groundwater is a likely cause of blackfoot disease in Taiwan, but microorganisms that potentially control arsenic mobility in the subsurface remain unstudied. The objective of this study was to investigate the relevant arsenite-oxidizing and arsenate-reducing microbial community that exists in highly arsenic-contaminated groundwater in Taiwan. We cultured and identified arsenic-transforming bacteria, analyzed arsenic resistance and transformation, and determined the presence of genetic markers for arsenic transformation. In total, 11 arsenic-transforming bacterial strains with different colony morphologies and varying arsenic transformation abilities were isolated, including 10 facultative anaerobic arsenate-reducing bacteria and one strictly aerobic arsenite-oxidizing bacterium. All of the isolates exhibited high levels of arsenic resistance with minimum inhibitory concentrations of arsenic ranging from 2 to 200 mM. Strain AR-11 was able to rapidly oxidize arsenite to arsenate at concentrations relevant to environmental groundwater samples without the addition of any electron donors or acceptors. We provide evidence that arsenic-reduction activity may be conferred by the ars operon(s) that were not amplified by the designed primers currently in use. The 16S rRNA sequence analysis grouped the isolates into the following genera: Pseudomonas, Bacillus, Psychrobacter, Vibrio, Citrobacter, Enterobacter, and Bosea. Among these genera, we present the first report of the genus Psychrobacter being involved in arsenic reduction. Our results further support the hypothesis that bacteria capable of either oxidizing arsenite or reducing arsenate coexist and are ubiquitous in arsenic-contaminated groundwater.

Conceptual Design Report for Remote-Handled Low-Level Waste Disposal Facility

Energy Technology Data Exchange (ETDEWEB)

Lisa Harvego; David Duncan; Joan Connolly; Margaret Hinman; Charles Marcinkiewicz; Gary Mecham

2010-10-01

This conceptual design report addresses development of replacement remote-handled low-level waste disposal capability for the Idaho National Laboratory. Current disposal capability at the Radioactive Waste Management Complex is planned until the facility is full or until it must be closed in preparation for final remediation (approximately at the end of Fiscal Year 2017). This conceptual design report includes key project assumptions; design options considered in development of the proposed onsite disposal facility (the highest ranked alternative for providing continued uninterrupted remote-handled low level waste disposal capability); process and facility descriptions; safety and environmental requirements that would apply to the proposed facility; and the proposed cost and schedule for funding, design, construction, and operation of the proposed onsite disposal facility.

Automatic Flight Control System Design of Level Change Mode for a Large Aircraft

Directory of Open Access Journals (Sweden)

Huajun Gong

2013-02-01

Full Text Available The level change mode is an essential part of large civil aircraft automatic flight control systems. In cruise, with the decrease of the plane's weight caused by fuel consumption and the influence of bad weather, such as thunderstorms, the level change mode is required to solve this problem. This work establishes a nonlinear model of large aircraft, takes level changed from 9500m to 10100m as an example to design control laws for the level change mode in cruise. The classical engineering method is used to design longitudinal and lateral control laws synthetically. The flight qualities are considered in the design process. Simulation results indicate the control laws can meet design requirements and have a good anti-gust performance.

Antimicrobial Resistance Profiles of Bacteria Isolated from the Nasal Cavity of Camels in Samburu, Nakuru, and Isiolo Counties of Kenya

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J. M. Mutua

2017-01-01

Full Text Available This study was designed to determine antimicrobial resistance profiles of bacteria isolated from the nasal cavity of healthy camels. A total of 255 nasal samples (swabs were collected in Isiolo, Samburu, and Nakuru counties, Kenya, from which 404 bacterial isolates belonging to various genera and species were recovered. The bacterial isolates included Bacillus (39.60%, coagulase-negative Staphylococcus (29.95%, Streptococcus species other than Streptococcus agalactiae (25.74%, coagulase-positive Staphylococcus (3.96%, and Streptococcus agalactiae (0.74%. Isolates were most susceptible to Gentamicin (95.8%, followed by Tetracycline (90.5%, Kanamycin and Chloramphenicol (each at 85.3%, Sulphamethoxazole (84.2%, Co-trimoxazole (82.1%, Ampicillin (78.9%, and finally Streptomycin (76.8%. This translated to low resistance levels. Multidrug resistance was also reported in 30.5% of the isolates tested. Even though the antibiotic resistance demonstrated in this study is low, the observation is significant, since the few resistant normal flora could be harboring resistance genes which can be transferred to pathogenic bacteria within the animal, to other animals’ bacteria and, most seriously, to human pathogens.

Obtaining Low Rank Coal Biotransforming Bacteria from Microhabitats Enriched with Carbonaceous Residues

International Nuclear Information System (INIS)

Valero Valero, Nelson; Rodriguez Salazar, Luz Nidia; Mancilla Gomez, Sandra; Contreras Bayona, Leydis

2012-01-01

Bacteria capable of low rank coal (LRC) biotransform were isolated from environmental samples altered with coal in the mine The Cerrejon. A protocol was designed to select strains more capable of LRC biotransform, the protocol includes isolation in a selective medium with LRC powder, qualitative and quantitative tests for LRC solubilization in solid and liquid culture medium. Of 75 bacterial strains isolated, 32 showed growth in minimal salts agar with 5 % carbon. The strains that produce higher values of humic substances (HS) have a mechanism of solubilization associated with pH changes in the culture medium, probably related to the production of extracellular alkaline substances by bacteria. The largest number of strains and bacteria with more solubilizing activity on LRC were isolated from sludge with high content of carbon residue and rhizosphere of Typha domingensis and Cenchrus ciliaris grown on sediments mixed with carbon particles, this result suggests that obtaining and solubilization capacity of LRC by bacteria may be related to the microhabitat where the populations originated.

Symbiotic bacteria contribute to increasing the population size of a freshwater crustacean, Daphnia magna.

Science.gov (United States)

Peerakietkhajorn, Saranya; Tsukada, Koji; Kato, Yasuhiko; Matsuura, Tomoaki; Watanabe, Hajime

2015-04-01

The filter-feeding crustacean Daphnia is a key organism in freshwater ecosystems. Here, we report the effect of symbiotic bacteria on ecologically important life history traits, such as population dynamics and longevity, in Daphnia magna. By disinfection of the daphniid embryos with glutaraldehyde, aposymbiotic daphniids were prepared and cultured under bacteria-free conditions. Removal of bacteria from the daphniids was monitored by quantitative polymerase chain reaction for bacterial 16S rRNA gene. The population of aposymbiotic daphniids was reduced 10-folds compared with that of the control daphniids. Importantly, re-infection with symbiotic bacteria caused daphniids to regain bacteria and increase their fecundity to the level of the control daphniids, suggesting that symbiotic bacteria regulate Daphnia fecundity. To identify the species of symbiotic bacteria, 16S rRNA genes of bacteria in daphniids were sequenced. This revealed that 50% of sequences belonged to the Limnohabitans sp. of the Betaproteobacteria class and that the diversity of bacterial taxa was relatively low. These results suggested that symbiotic bacteria have a beneficial effect on D. magna, and that aposymbiotic Daphnia are useful tools in understanding the role of symbiotic bacteria in the environmental responses and evolution of their hosts. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

Alternative concepts for Low-Level Radioactive Waste Disposal: Conceptual design report

International Nuclear Information System (INIS)

1987-06-01

This conceptual design report is provided by the Department of Energy's Nuclear Energy Low-Level Waste Management Program to assist states and compact regions in developing new low-level radioactive waste (LLW) disposal facilities in accordance with the Low-Level Radioactive Waste Policy Amendment Act of 1985. The report provides conceptual designs and evaluations of six widely considered concepts for LLW disposal. These are shallow land disposal (SLD), intermediate depth disposal (IDD), below-ground vaults (BGV), above-ground vaults (AGV), modular concrete canister disposal (MCCD), earth-mounded concrete bunker (EMCB). 40 refs., 45 figs., 77 tabs

Social behavior of bacteria: from physics to complex organization

Science.gov (United States)

Ben-Jacob, E.

2008-10-01

I describe how bacteria develop complex colonial patterns by utilizing intricate communication capabilities, such as quorum sensing, chemotactic signaling and exchange of genetic information (plasmids) Bacteria do not store genetically all the information required for generating the patterns for all possible environments. Instead, additional information is cooperatively generated as required for the colonial organization to proceed. Each bacterium is, by itself, a biotic autonomous system with its own internal cellular informatics capabilities (storage, processing and assessments of information). These afford the cell certain plasticity to select its response to biochemical messages it receives, including self-alteration and broadcasting messages to initiate alterations in other bacteria. Hence, new features can collectively emerge during self-organization from the intra-cellular level to the whole colony. Collectively bacteria store information, perform decision make decisions (e.g. to sporulate) and even learn from past experience (e.g. exposure to antibiotics)-features we begin to associate with bacterial social behavior and even rudimentary intelligence. I also take Schrdinger’s’ “feeding on negative entropy” criteria further and propose that, in addition organisms have to extract latent information embedded in the environment. By latent information we refer to the non-arbitrary spatio-temporal patterns of regularities and variations that characterize the environmental dynamics. In other words, bacteria must be able to sense the environment and perform internal information processing for thriving on latent information embedded in the complexity of their environment. I then propose that by acting together, bacteria can perform this most elementary cognitive function more efficiently as can be illustrated by their cooperative behavior.

Radiation-resistant asporogenic bacteria

Energy Technology Data Exchange (ETDEWEB)

Yano, K [Tokyo Univ. (Japan). Faculty of Agriculture

1975-09-01

This paper reports the biological and ecological examinations on the radiation-resistant asporogenic bacteria (mainly concerning Micrococcus radiodurans). Radiation-resistant asporogenic bacteria were isolated from the irradiated areas of the natural world as well as from the general areas and from the Rn waters in the Misasa hot spring. The acquiring of the tolerance to radiation in bacteria was also examined. In addition, the future problems of microbiological treatment with irradiation were mentioned.

Radiation-resistant asporogenic bacteria

International Nuclear Information System (INIS)

Yano, Keiji

1975-01-01

This paper reports the biological and ecological examinations on the radiation-resistant asporogenic bacteria (mainly concerning Micrococcus radiodurans). Radiation-resistant asporogenic bacteria were isolated from the irradiated areas of the natural world as well as from the general areas and from the Rn waters in the Misasa hot spring. The acquiring of the tolerance to radiation in bacteria was also examined. In addition, the future problems of microbiological treatment with irradiation were mentioned. (Tsukamoto, Y.)

Immunomodulatory properties of probiotic bacteria

DEFF Research Database (Denmark)

Fink, Lisbeth Nielsen

2007-01-01

Certain lactic acid bacteria (LAB) are part of the commensal intestinal flora and considered beneficial for health, as they compete with pathogens for adhesion sites in the intestine and ferment otherwise indigestible compounds. Another important property of these so-called probiotic bacteria...... with bacteria, and the cytokine pattern induced by specific bacteria resembled the pattern induced in MoDC, except for TNF-alpha and IL-6, which were induced in response to different bacteria in blood DC/monocytes and monocyte-derived DC. Autologous NK cells produced IFN-gamma when cultured with blood DC......, monocytes and monocyte-derived DC and IL-12-inducing bacteria, whereas only DC induced IFN-gamma production in allogeneic T cells. In vitro-generated DC is a commonly used model of tissue DC, but they differ in certain aspects from intestinal DC, which are in direct contact with the intestinal microbiota...

Multicenter Evaluation of the Bruker MALDI Biotyper CA System for the Identification of Clinically Important Bacteria and Yeasts.

Science.gov (United States)

Wilson, Deborah A; Young, Stephen; Timm, Karen; Novak-Weekley, Susan; Marlowe, Elizabeth M; Madisen, Neil; Lillie, Jennifer L; Ledeboer, Nathan A; Smith, Rebecca; Hyke, Josh; Griego-Fullbright, Christen; Jim, Patricia; Granato, Paul A; Faron, Matthew L; Cumpio, Joven; Buchan, Blake W; Procop, Gary W

2017-06-01

A report on the multicenter evaluation of the Bruker MALDI Biotyper CA System (MBT-CA; Bruker Daltonics, Billerica, MA) for the identification of clinically important bacteria and yeasts. In total, 4,399 isolates of medically important bacteria and yeasts were assessed in the MBT-CA. These included 2,262 aerobic gram-positive (AGP) bacteria, 792 aerobic gram-negative (AGN) bacteria 530 anaerobic (AnA) bacteria, and 815 yeasts (YSTs). Three processing methods were assesed. Overall, 98.4% (4,329/4,399) of all bacterial and yeast isolates were correctly identified to the genus and species/species complex level, and 95.7% of isolates were identified with a high degree of confidence. The percentage correctly identified and the percentage identified correctly with a high level of confidence, respectively, were as follows: AGP bacteria (98.6%/96.5%), AGN bacteria (98.5%/96.8%), AnA bacteria (98.5%/97.4%), and YSTs (97.8%/87.6%). The extended direct transfer method was only minimally superior to the direct transfer method for bacteria (89.9% vs 86.8%, respectively) but significantly superior for yeast isolates (74.0% vs 48.9%, respectively). The Bruker MALDI Biotyper CA System accurately identifies most clinically important bacteria and yeasts and has optional processing methods to improve isolate characterization. © American Society for Clinical Pathology, 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

System Level Design of Reconfigurable Server Farms Using Elliptic Curve Cryptography Processor Engines

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Sangook Moon

2014-01-01

Full Text Available As today’s hardware architecture becomes more and more complicated, it is getting harder to modify or improve the microarchitecture of a design in register transfer level (RTL. Consequently, traditional methods we have used to develop a design are not capable of coping with complex designs. In this paper, we suggest a way of designing complex digital logic circuits with a soft and advanced type of SystemVerilog at an electronic system level. We apply the concept of design-and-reuse with a high level of abstraction to implement elliptic curve crypto-processor server farms. With the concept of the superior level of abstraction to the RTL used with the traditional HDL design, we successfully achieved the soft implementation of the crypto-processor server farms as well as robust test bench code with trivial effort in the same simulation environment. Otherwise, it could have required error-prone Verilog simulations for the hardware IPs and other time-consuming jobs such as C/SystemC verification for the software, sacrificing more time and effort. In the design of the elliptic curve cryptography processor engine, we propose a 3X faster GF(2m serial multiplication architecture.

A Multi-step and Multi-level approach for Computer Aided Molecular Design

DEFF Research Database (Denmark)

. The problem formulation step incorporates a knowledge base for the identification and setup of the design criteria. Candidate compounds are identified using a multi-level generate and test CAMD solution algorithm capable of designing molecules having a high level of molecular detail. A post solution step...... using an Integrated Computer Aided System (ICAS) for result analysis and verification is included in the methodology. Keywords: CAMD, separation processes, knowledge base, molecular design, solvent selection, substitution, group contribution, property prediction, ICAS Introduction The use of Computer...... Aided Molecular Design (CAMD) for the identification of compounds having specific physic...

Raingarden Soil Bacteria Community Response to Lab Simulated Salt-Enriched Artificial Stormwater

Science.gov (United States)

Endreny, T. A.

2014-12-01

Cold climate cities with green infrastructure depend on soil bacteria to remove nutrients from road salt-enriched stormwater. Our research examined how bacterial communities in laboratory columns containing bioretention media responded to varying concentrations of salt exposure from artificial stormwater and the effect of bacteria and salt on column effluent concentrations. We used a factorial design with two bacteria treatments (sterile, nonsterile) and three salt concentrations (935, 315, and 80 ppm), including a deionized water control. Columns were repeatedly saturated with stormwater or deionized and then drained throughout 5 wk, with the last week of effluent analyzed for water chemistry. To examine bacterial communities, we extracted DNA from column bioretention media at time 0 and at week 5 and used molecular profiling techniques to examine bacterial community changes. We found that bacterial community taxa changed between time 0 and week 5 and that there was significant separation between taxa among salt treatments. Bacteria evenness was significantly affected by stormwater treatment, but there were no differences in bacterial richness or diversity. Soil bacteria and salt treatments had a significant effect on the effluent concentration of NO3, PO4, Cu, Pb, and Zn based on ANOVA tests. The presence of bacteria reduced effluent NO3 and Zn concentrations by as much as 150 and 25%, respectively, while having a mixed effect on effluent PO4 concentrations. Our results demonstrate how stormwater can affect bacterial communities and how the presence of soil bacteria improves pollutant removal by green infrastructure.

Genomic and phylogenetic characterization of luminous bacteria symbiotic with the deep-sea fish Chlorophthalmus albatrossis (Aulopiformes: Chlorophthalmidae).

Science.gov (United States)

Dunlap, Paul V; Ast, Jennifer C

2005-02-01

Bacteria forming light-organ symbiosis with deep-sea chlorophthalmid fishes (Aulopiformes: Chlorophthalmidae) are considered to belong to the species Photobacterium phosphoreum. The identification of these bacteria as P. phosphoreum, however, was based exclusively on phenotypic traits, which may not discriminate between phenetically similar but evolutionarily distinct luminous bacteria. Therefore, to test the species identification of chlorophthalmid symbionts, we carried out a genomotypic (repetitive element palindromic PCR genomic profiling) and phylogenetic analysis on strains isolated from the perirectal light organ of Chlorophthalmus albatrossis. Sequence analysis of the 16S rRNA gene of 10 strains from 5 fish specimens placed these bacteria in a cluster related to but phylogenetically distinct from the type strain of P. phosphoreum, ATCC 11040(T), and the type strain of Photobacterium iliopiscarium, ATCC 51760(T). Analysis of gyrB resolved the C. albatrossis strains as a strongly supported clade distinct from P. phosphoreum and P. iliopiscarium. Genomic profiling of 109 strains from the 5 C. albatrossis specimens revealed a high level of similarity among strains but allowed identification of genomotypically different types from each fish. Representatives of each type were then analyzed phylogenetically, using sequence of the luxABFE genes. As with gyrB, analysis of luxABFE resolved the C. albatrossis strains as a robustly supported clade distinct from P. phosphoreum. Furthermore, other strains of luminous bacteria reported as P. phosphoreum, i.e., NCIMB 844, from the skin of Merluccius capensis (Merlucciidae), NZ-11D, from the light organ of Nezumia aequalis (Macrouridae), and pjapo.1.1, from the light organ of Physiculus japonicus (Moridae), grouped phylogenetically by gyrB and luxABFE with the C. albatrossis strains, not with ATCC 11040(T). These results demonstrate that luminous bacteria symbiotic with C. albatrossis, together with certain other strains of

Development of Electrochemical Biosensors for Ultrasensitive Detection of Bacteria in the Environment

DEFF Research Database (Denmark)

Fapyane, Deby

2018-01-01

to those conventional methods, are intensively studied. Biosensor technology is one of the strategies for rapid monitoring of pathogens such as bacteria, virus, and parasites in the environment. Among them, the electrochemical biosensor offers simple, rapid, cost-effective and possibility...... for ultrasensitive detection of bacterial cells, DNA and rRNA. Several key operational parameters were assessed such as the optimization of probe design and labeling molecules. Here, more specifically we used two novel labels for the development of the electrochemical biosensor for bacteria detection; cellulase...

Heavy metals detoxification in soil performed by sulfate - reducing bacteria

International Nuclear Information System (INIS)

Pado, R.; Pawlowska-Cwiek, L.; Szwagrzyk, J.

1994-01-01

The process of sulfate reduction carried out by mixed bacteria cultures in the presence of heavy cations (Fe 2+ , Pb 2+ , Cd 2+ , Zn 2+ , Cu 2+ ) was investigated. The range of harmful metals concentrations responded to the acceptable levels in soil and their multiplications (10-100 times) in contaminated soil. The results show the possibility of detoxicating these metals, especially lead. In the highest lead concentrations (3950 and 7500 ppm), only after one month of activities conducted by bacteria dissimilating hydrogen sulfide, between about 73 and 81 per cent of lead was converted into practically insoluble PbS. It was found that detoxication process with the presence of bacteria from this group prolonged with the increase of metal concentration (Zn 2+ and Cd 2+ in particular. (author). 30 refs, 5 figs, 3 tabs

Reprogrammable Controller Design From High-Level Specification

Directory of Open Access Journals (Sweden)

M. Benmohammed

2003-10-01

Full Text Available Existing techniques in high-level synthesis mostly assume a simple controller architecture model in the form of a single FSM. However, in reality more complex controller architectures are often used. On the other hand, in the case of programmable processors, the controller architecture is largely defined by the available control-flow instructions in the instruction set. With the wider acceptance of behavioral synthesis, the application of these methods for the design of programmable controllers is of fundamental importance in embedded system technology. This paper describes an important extension of an existing architectural synthesis system targeting the generation of ASIP reprogrammable architectures. The designer can then generate both style of architecture, hardwired and programmable, using the same synthesis system and can quickly evaluate the trade-offs of hardware decisions.

Energetics and Application of Heterotrophy in Acetogenic Bacteria.

Science.gov (United States)

Schuchmann, Kai; Müller, Volker

2016-07-15

Acetogenic bacteria are a diverse group of strictly anaerobic bacteria that utilize the Wood-Ljungdahl pathway for CO2 fixation and energy conservation. These microorganisms play an important part in the global carbon cycle and are a key component of the anaerobic food web. Their most prominent metabolic feature is autotrophic growth with molecular hydrogen and carbon dioxide as the substrates. However, most members also show an outstanding metabolic flexibility for utilizing a vast variety of different substrates. In contrast to autotrophic growth, which is hardly competitive, metabolic flexibility is seen as a key ability of acetogens to compete in ecosystems and might explain the almost-ubiquitous distribution of acetogenic bacteria in anoxic environments. This review covers the latest findings with respect to the heterotrophic metabolism of acetogenic bacteria, including utilization of carbohydrates, lactate, and different alcohols, especially in the model acetogen Acetobacterium woodii Modularity of metabolism, a key concept of pathway design in synthetic biology, together with electron bifurcation, to overcome energetic barriers, appears to be the basis for the amazing substrate spectrum. At the same time, acetogens depend on only a relatively small number of enzymes to expand the substrate spectrum. We will discuss the energetic advantages of coupling CO2 reduction to fermentations that exploit otherwise-inaccessible substrates and the ecological advantages, as well as the biotechnological applications of the heterotrophic metabolism of acetogens. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

The increasing of beta-defensin-2 level in saliva after probiotic Lactobacillus reuteri administration

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Tuti Kusumaningsih

2015-03-01

Full Text Available Background: Commesal bacteria is an excellent inducer for beta defensin-2 (BD-2. Probiotics bacteria Lactobacillus reuteri (L. reuteri as commensal bacteria may play the same role as an excellent inducer for BD-2. Beta defensin is natural antimicrobial peptides widely expressed in oral cavity, including in epithelium salivary gland. Streptococcus mutans (S. mutans as the main of bacteria causing caries are sensitive to BD-2. Purpose: This research was aimed to determine whether administration of probiotic L. reuteri can increase salivary BD-2 level in Wistar rats. Methods: This research can be considered as a laboratory experimental research with a randomized control group post test only design. Twenty-four male Rattus norvegicus Wistar strain rats aged 3 months were used. They were randomly divided into four groups, namely two control groups (negative control group that was not induced and positive control group induced with S. mutans, and two treatment groups (K1: induced with L. reuteri for 14 days and S. mutans for 7 days, and K2: induced with L. reuteri and S. mutans simultaneously for 14 days. L. reuteri culture at a concentration of 108 CFU/ml and S. mutans culture at a concentration of 1010CFU/ml were induced into the oral cavity of Wistar rats. An examination of BD-2 level was then conducted by using Elisa techniques. results: There was significant difference of salivary BD-2 level among those treatment groups (p=0.001. BD-2 level in saliva was increased after the administration of L. reuteri. Conclusion: L. reuteri probiotic can increase salivary BD-2 level in Wistar rats.

Bacteria-surface interactions.

Science.gov (United States)

Tuson, Hannah H; Weibel, Douglas B

2013-05-14

The interaction of bacteria with surfaces has important implications in a range of areas, including bioenergy, biofouling, biofilm formation, and the infection of plants and animals. Many of the interactions of bacteria with surfaces produce changes in the expression of genes that influence cell morphology and behavior, including genes essential for motility and surface attachment. Despite the attention that these phenotypes have garnered, the bacterial systems used for sensing and responding to surfaces are still not well understood. An understanding of these mechanisms will guide the development of new classes of materials that inhibit and promote cell growth, and complement studies of the physiology of bacteria in contact with surfaces. Recent studies from a range of fields in science and engineering are poised to guide future investigations in this area. This review summarizes recent studies on bacteria-surface interactions, discusses mechanisms of surface sensing and consequences of cell attachment, provides an overview of surfaces that have been used in bacterial studies, and highlights unanswered questions in this field.

Marine Pseudomonas putida: a potential source of antimicrobial substances against antibiotic-resistant bacteria

Directory of Open Access Journals (Sweden)

Palloma Rodrigues Marinho

2009-08-01

Full Text Available Bacteria isolated from marine sponges found off the coast of Rio de Janeiro, Brazil, were screened for the production of antimicrobial substances. We report a new Pseudomonas putida strain (designated P. putida Mm3 isolated from the sponge Mycale microsigmatosa that produces a powerful antimicrobial substance active against multidrug-resistant bacteria. P. putida Mm3 was identified on the basis of 16S rRNA gene sequencing and phenotypic tests. Molecular typing for Mm3 was performed by RAPD-PCR and comparison of the results to other Pseudomonas strains. Our results contribute to the search for new antimicrobial agents, an important strategy for developing alternative therapies to treat infections caused by multidrug-resistant bacteria.

Marine Pseudomonas putida: a potential source of antimicrobial substances against antibiotic-resistant bacteria.

Science.gov (United States)

Marinho, Palloma Rodrigues; Moreira, Ana Paula Barbosa; Pellegrino, Flávia Lúcia Piffano Costa; Muricy, Guilherme; Bastos, Maria do Carmo de Freire; Santos, Kátia Regina Netto dos; Giambiagi-deMarval, Marcia; Laport, Marinella Silva

2009-08-01

Bacteria isolated from marine sponges found off the coast of Rio de Janeiro, Brazil, were screened for the production of antimicrobial substances. We report a new Pseudomonas putida strain (designated P. putida Mm3) isolated from the sponge Mycale microsigmatosa that produces a powerful antimicrobial substance active against multidrug-resistant bacteria. P. putida Mm3 was identified on the basis of 16S rRNA gene sequencing and phenotypic tests. Molecular typing for Mm3 was performed by RAPD-PCR and comparison of the results to other Pseudomonas strains. Our results contribute to the search for new antimicrobial agents, an important strategy for developing alternative therapies to treat infections caused by multidrug-resistant bacteria.

High hydrostatic pressure inactivation of total aerobic bacteria, lactic acid bacteria, yeasts in sour Chinese cabbage.

Science.gov (United States)

Li, Lin; Feng, Lun; Yi, Junjie; Hua, Cheng; Chen, Fang; Liao, Xiaojun; Wang, Zhengfu; Hu, Xiaosong

2010-08-15

This study investigated the inactivation of total aerobic bacteria (TAB), lactic acid bacteria (LAB), yeasts in sour Chinese cabbage (SCC) treated by high hydrostatic pressure (HHP). The pressure level ranged from 200 to 600 MPa and the treatment time were 10-30 min. All samples were stored at 4, 27 and 37 degrees C for 90 days. The pressure level of 200 MPa had no significant impact on these microorganisms. The counts of TAB were significantly reduced by 2.7-4.0 log(10)CFU/g at 400 MPa and 4.2-4.5 log(10)CFU/g at 600 MPa from 6.2 log(10)CFU/g; the counts of LAB were also reduced by 2.4-4.3 log(10)CFU/g at 400 MPa from 7.0 log(10)CFU/g and LAB was completely inactivated at 600 MPa; the counts of yeasts were reduced by 1.5-2.0 log(10)CFU/g at 400 and 600 MPa from 4.2 log(10)CFU/g. Storage temperatures significantly influenced the microbial proliferation in HHP-treated SCC depending on the pressure levels. The surviving TAB and LAB at 400 MPa equaled initial counts after 15-day storage at 27 and 37 degrees C, whereas they were inhibited at 4 degrees C up to 60 days. The surviving TAB at 600 MPa did not grow. Yeasts at 400 and 600 MPa decreased below detectable level after 2 days at all the three storage temperatures. From the microbial safety point of view, the result indicated that HHP at 600 MPa could be used as an alternative preservation method for SCC. Copyright 2010 Elsevier B.V. All rights reserved.

Genomics of Probiotic Bacteria

Science.gov (United States)

O'Flaherty, Sarah; Goh, Yong Jun; Klaenhammer, Todd R.

Probiotic bacteria from the Lactobacillus and Bifidobacterium species belong to the Firmicutes and the Actinobacteria phylum, respectively. Lactobacilli are members of the lactic acid bacteria (LAB) group, a broadly defined family of microorganisms that ferment various hexoses into primarily lactic acid. Lactobacilli are typically low G + C gram-positive species which are phylogenetically diverse, with over 100 species documented to date. Bifidobacteria are heterofermentative, high G + C content bacteria with about 30 species of bifidobacteria described to date.

Design, characterization and applications of new ionic liquid matrices for multifunctional analysis of biomolecules: A novel strategy for pathogenic bacteria biosensing

International Nuclear Information System (INIS)

Abdelhamid, Hani Nasser; Khan, M Shahnawaz; Wu, Hui-Fen

2014-01-01

Highlights: • Design and characterize novel UV absorbed-ionic liquid matrices series. • Apply the new series for different analytes. • Introduce a novel methodology for pathogenic bacteria biosensing. • Tabulate the physical parameters of the new series. - Abstract: The design, preparation and performance for novel UV-light absorbing (room-temperature) ionic liquid matrices (UV-RTILMs) for matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS) were reported. A series of UV-RTILMs was prepared by ultrasonication of equimolar of acid (mefenamic acid) and bases (aniline (ANI), pyridine (Pyr), dimethyl aniline (DMANI) and 2-methyl picoline (2-P)). The UV-RTILMs have not only significant absorbance at the desired wavelength (337 nm of the N 2 Laser), but also have available protons that can easily undergo proton transfer reactions to ionize the target molecules. The novel UV-RTILMs have the ability to ionize different and wide classes of compounds such as drugs, carbohydrate, and amino acids. The new UV-RTILMs series have been successfully and selectively applied for biosensing the lysates of pathogenic bacteria in the presence of the cell macromolecules. A new strategy for biosensing pathogens was presented via sensing the pathogens lysate in the cell suspension. The new materials can effectively detect the bacterial toxins without separation or any pretreatment. They offered excellent ionization of labile oligosaccharides with protonated peaks. They could significantly enhance the analyte signals, produce homogeneous spotting, reducing spot-to-spot variation, excellent vacuum stability, higher ion peak intensity, and wide application possibility. The physical parameters such as molar refractivity, molar volume, parachor, surface tension, density and polarizability were calculated and tabulated. The new UV-RTILMs could offer excellent reproducibility and great repeatability and they are promising matrices for wide applications on MALDI-MS

Design, characterization and applications of new ionic liquid matrices for multifunctional analysis of biomolecules: A novel strategy for pathogenic bacteria biosensing

Energy Technology Data Exchange (ETDEWEB)

Abdelhamid, Hani Nasser [Department of Chemistry, National Sun Yat-Sen University, Kaohsiung, 804, Taiwan (China); Department of Chemistry, Assuit University, Assuit, 71515 (Egypt); Khan, M Shahnawaz [Doctoral Degree Program in Marine Biotechnology, National Sun Yat-Sen University, Kaohsiung, 804, Taiwan (China); Wu, Hui-Fen, E-mail: hwu@faculty.nsysu.edu.tw [Department of Chemistry, National Sun Yat-Sen University, Kaohsiung, 804, Taiwan (China); School of Pharmacy, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, 800, Taiwan (China); Institute of Medical Science and Technology, National Sun Yat-Sen University, Kaohsiung, 804, Taiwan (China); Doctoral Degree Program in Marine Biotechnology, National Sun Yat-Sen University, Kaohsiung, 804, Taiwan (China); Center for Nanoscience and Nanotechnology, National Sun Yat-Sen University, Kaohsiung, 804, Taiwan (China)

2014-05-01

Highlights: • Design and characterize novel UV absorbed-ionic liquid matrices series. • Apply the new series for different analytes. • Introduce a novel methodology for pathogenic bacteria biosensing. • Tabulate the physical parameters of the new series. - Abstract: The design, preparation and performance for novel UV-light absorbing (room-temperature) ionic liquid matrices (UV-RTILMs) for matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS) were reported. A series of UV-RTILMs was prepared by ultrasonication of equimolar of acid (mefenamic acid) and bases (aniline (ANI), pyridine (Pyr), dimethyl aniline (DMANI) and 2-methyl picoline (2-P)). The UV-RTILMs have not only significant absorbance at the desired wavelength (337 nm of the N{sub 2} Laser), but also have available protons that can easily undergo proton transfer reactions to ionize the target molecules. The novel UV-RTILMs have the ability to ionize different and wide classes of compounds such as drugs, carbohydrate, and amino acids. The new UV-RTILMs series have been successfully and selectively applied for biosensing the lysates of pathogenic bacteria in the presence of the cell macromolecules. A new strategy for biosensing pathogens was presented via sensing the pathogens lysate in the cell suspension. The new materials can effectively detect the bacterial toxins without separation or any pretreatment. They offered excellent ionization of labile oligosaccharides with protonated peaks. They could significantly enhance the analyte signals, produce homogeneous spotting, reducing spot-to-spot variation, excellent vacuum stability, higher ion peak intensity, and wide application possibility. The physical parameters such as molar refractivity, molar volume, parachor, surface tension, density and polarizability were calculated and tabulated. The new UV-RTILMs could offer excellent reproducibility and great repeatability and they are promising matrices for wide applications on MALDI-MS.

Impact of ITER liquid metal design options on safety level and licensing - Sweden

International Nuclear Information System (INIS)

Harfors, C.; Devell, L.; Johansson, Kjell; Lundell, B.; Rolandsson, S.

1993-01-01

The safety level and licensability of five design options for ITER coolant, breeding material and structural material are assessed, with emphasis on some specified accident scenarios. The safety level is assessed in terms of barrier requirements and the feasibility to construct and qualify such a barrier. The licensability in Sweden of each design option is assessed based on the indicated safety level and on a judgement of the technical feasibility to construct and qualify the ITER tokamak itself, based on the selected design option. 20 refs

Requirements for High Level Models Supporting Design Space Exploration in Model-based Systems Engineering

OpenAIRE

Haveman, Steven P.; Bonnema, G. Maarten

2013-01-01

Most formal models are used in detailed design and focus on a single domain. Few effective approaches exist that can effectively tie these lower level models to a high level system model during design space exploration. This complicates the validation of high level system requirements during detailed design. In this paper, we define requirements for a high level model that is firstly driven by key systems engineering challenges present in industry and secondly connects to several formal and d...

Nitrogen-fixing methane-utilizing bacteria

NARCIS (Netherlands)

Bont, de J.A.M.

1976-01-01

Methane occurs abundantly in nature. In the presence of oxygen this gas may be metabolized by bacteria that are able to use it as carbon and energy source. Several types of bacteria involved in the oxidation of methane have been described in literature. Methane-utilizing bacteria have in

Pathogenic Assay of Probiotic Bacteria Producing Proteolytic Enzymes as Bioremediation Bacteria Against Vannamei Shrimp Larvae (Litopenaeus vannamei)

OpenAIRE

Wilis Ari Setyati; Muhammad Zainuddin; Person Pesona Renta

2017-01-01

Application of bacteria in bioremediation of shrimp culture ponds is one of the methods used to clean internal pollutants. This study aimed to evaluate the pathogenicity of extracellular proteolytic enzyme produced by the probiotic bacteria as bioremediation bacteria on vannamei shrimp larvae culture. There were five probiotic bacteria, which were successfully isolated from the sediments served as substrate in mangrove area. The isolated bacteria were coded in number as 13, 19, 30, 33, and 36...

Taurocholate Deconjugation and Cholesterol Binding by Indigenous Dadih Lactic Acid Bacteria

Directory of Open Access Journals (Sweden)

USMAN PATO

2005-09-01

Full Text Available High serum cholesterol levels have been associated with an increased risk for human coronary heart disease. Lowering of serum cholesterol has been suggested to prevent the heart disease. To reduce serum cholesterol levels one may consumed diet supplementat of fermented dairy product such as dadih. Lactic acid bacteria present in dadih may alter serum cholesterol by directly bind to dietary cholesterol and/or deconjugation of bile salts. Acid and bile tolerance, deconjugation of sodium taurocholate, and the cholesterol-binding ability of lactic acid bacteria from dadih were examined. Among ten dadih lactic acid bacteria tested, six strains namely I-11, I-2775, K-5, I-6257, IS-7257, and B-4 could bind cholesterol and deconjugate sodium taurocholate. However, the last four strains were very sensitive to bile. Therefore, Lactobacillus fermentum I-11 and Leuconostoc lactis subsp. lactis I-2775 those were tolerant to acid and oxgall (bile and deconjugated sodium taurocholate and bound cholesterol could be recommended as probiotic to prevent coronary heart disease.

Cadmium resistance of endophytic bacteria and rizosféricas bacteria isolated from Oriza sativa in Colombia

Directory of Open Access Journals (Sweden)

Nataly Ayubb T

2017-12-01

Full Text Available The present study had as objective to evaluate in vitro the resistance of endophytic bacteria and rizospheric bacteria to different concentrations of Cadmium.This bacteria were isolated fron different tissues of commercial rice varieties and from bacteria isolated from the rhizosphere in rice plantations of the Nechí (Antioquía and Achí (Bolivar.  Plant growth promotion was evaluated in vitro by nitrogen fixation, phosphate solubilization and siderophores production of endophytic bacteria. Of each tissue isolated from rice plants was carried out isolation in culture medium for endophytic bacteria, and the soil samples were serially diluted in peptone water. Each sample was determined the population density by counting in CFU / g of tissue and morphotypes were separated by shape, color, size and appearance in culture media. Significant differences were observed for density population of bacteria with respect to tissue, with higher values in root (4x1011 g/root, followed of the stem (3x1010g/etem, leaf (5x109 g/ leaf, flag leaf (3x109 g/ flag leaf and with less density in panicle (4x108 g/panicle. The results of the identification with kit API were confirmed the presence of endophytic bacteria Burkholderia cepaceae and rizospheric bacteria Pseudomona fluorescens With the ability to tolerate different concentrations of Cd, fix nitrogen, solubilize phosphates and produce siderophores.

Infection Vibrio sp. Bacteria on Kappaphycus Seaweed Varieties Brown and Green

Science.gov (United States)

Irmawati, Yuni; Sudirjo, Fien

2017-10-01

Disease in seaweed or ice-ice, until today is still a major problem in the cultivation of seaweed. Changes in extreme environmental conditions is a trigger factor of ice-ice, which can result in seaweed susceptible to infection with pathogenic microorganisms, such as bacteria Vibrio sp. This research aims to determine the bacteria Vibrio sp. infection in seaweed Kappaphycus varieties of brown and green. Vibrio sp. bacteria isolated in the infected seaweed thallus ice-ice, grown on TCBS media, purification, gram staining and biochemical tests. Vibrio sp. infected to seaweed Kappaphycus brown and green varieties in containers controlled by different density, 105 CFU/ml, 106 CFU/ml and 107CFU/ml. Observations were made to change clinical effect in thallus seaweed for 14 days of observation. The results obtained show that the levels of infection bacteria Vibrio sp. higher in seaweed Kappaphycus green varieties both in density 105 CFU/ml, 106 CFU/ml and 107CFU/ml, when compared with varieties brown.

The influence of peat water to the colony number of aerob bacteria in mouth

Directory of Open Access Journals (Sweden)

Peni Purwandari

2016-08-01

Full Text Available Peatlands in Borneo is the second which the pH is 32% below normal that is 2-5, the pH of the acid contained in the peat water can trigger the acid environment of the oral cavity resulting in increased aerobic bacteria of the oral cavity. Most small communities of South Kalimantan who lives inland which is unreachable with clean water still use peat water for daily necessities. The purpose of this study was to determine the effect of peat water to the number of aerobic bacteria colonies of the oral cavity. This study used the quasi-experimental research design with pre-posttest control group design. The study sample consisted of 20 students of Faculty of Dentistry, Lambung Mangkurat University. The research used peat water after mouth rinsing with 10 ml of water and then the number of aerobic bacteria colonies which were present in bacterial growth media was counted. The result of this study showed that the result of paired t-test showed no significant differences between the groups before and after rinsing with  peat water (p = 0.001 (p <0.005. Based on the research we conclude that the peat water may cause an increasing in the number of colonies of aerobic bacteria of the oral cavity.

Stimulate The Growth of Rice Using Endophytic Bacteria from Lowland Rice Plant Tissue

Directory of Open Access Journals (Sweden)

Nuni Gofar

2015-07-01

Full Text Available Exploration and selection of endophytic bacteria from healthy food crops grown in lowland ecosystem is important to be conducted in order to get growth-stimulating endophytic bacteria at soil with low fertility level so that capable to optimize initial growth of food crops and subsequently can increase productivity level of lowland soil.The research objective was to isolate and to test the IAA-producing endophytic bacteria isolate in stimulating the rice crop growth at lowland area. Endophytic bacteria are isolated from tissues of rice, corn and peanut crops which grown at shallow swamp land in Ogan Ilir and Ogan Komering Ilir Districts, South Sumatra, Indonesia. There was nine isolates of nitrogen-fixer endophytic bacteria that capable to contribute IAA phytohormone into their growth media. The P31 isolate from rice crop tisssue of 2 months old produce the best rice sprouts than other isolates. This isolate can contribute of about 10 mg kg-1 IAA to its growth medium and increase the crowns dry weight and the roots dry weight respectively with magnitudes of 133% and 225% compared to control treatment. Concentration and absorbtion of N for rice crops innoculated with P31 isolates had increased by 169% and 400%, recpectively. The P31 isolates had been identified as Burkholderia pseudomallei (also known as Pseudomonas pseudomallei.

Amniotic fluid protein profiles of intraamniotic inflammatory response to Ureaplasma spp. and other bacteria.

Science.gov (United States)

Kacerovsky, Marian; Celec, Peter; Vlkova, Barbora; Skogstrand, Kristin; Hougaard, David M; Cobo, Teresa; Jacobsson, Bo

2013-01-01

This study aimed to evaluate the amniotic fluid protein profiles and the intensity of intraamniotic inflammatory response to Ureaplasma spp. and other bacteria, using the multiplex xMAP technology. A retrospective cohort study was undertaken in the Department of Obstetrics and Gynecology, University Hospital Hradec Kralove, Czech Republic. A total of 145 pregnant women with preterm prelabor rupture of membranes between gestational age 24+0 and 36+6 weeks were included in the study. Amniocenteses were performed. The presence of Ureaplasma spp. and other bacteria was evaluated using 16S rRNA gene sequencing. The levels of specific proteins were determined using multiplex xMAP technology. The presence of Ureaplasma spp. and other bacteria in the amniotic fluid was associated with increased levels of interleukin (IL)-6, IL-8, IL-10, brain-derived neurotropic factor, granulocyte macrophage colony stimulating factor, monocyte chemotactic protein-1, macrophage inflammatory protein-1, and matrix metalloproteinasis-9. Ureaplasma spp. were also associated with increased levels of neurotropin-3 and triggering receptor expressed on myeloid cells-1. The presence of Ureaplasma spp. in the amniotic fluid is associated with a slightly different protein profile of inflammatory response, but the intensity of inflammatory response to Ureaplasma spp. is comparable with the inflammatory response to other bacteria.

Method of Detecting Coliform Bacteria and Escherichia Coli Bacteria from Reflected Light

Science.gov (United States)

Vincent, Robert (Inventor)

2013-01-01

The present invention relates to a method of detecting coliform bacteria in water from reflected light and a method of detecting Eschericha Coli bacteria in water from reflected light, and also includes devices for the measurement, calculation and transmission of data relating to that method.

Antimicrobial susceptibility of starter culture bacteria used in Norwegian dairy products.

Science.gov (United States)

Katla, A K; Kruse, H; Johnsen, G; Herikstad, H

2001-07-20

Commercial starter culture bacteria are widely used in the production of dairy products and could represent a potential source for spread of genes encoding resistance to antimicrobial agents. To learn more about the antimicrobial susceptibility of starter culture bacteria used in Norwegian dairy products, a total of 189 isolates of lactic acid bacteria were examined for susceptibility to ampicillin, penicillin G, cephalothin, vancomycin, bacitracin, gentamicin, streptomycin, erythromycin, tetracycline, chloramphenicol, quinupristin/dalfopristin, ciprofloxacin, trimethoprim and sulphadiazine using Etest for MIC determination. Most of the isolates (140) originated from 39 dairy products (yoghurt, sour cream, fermented milk and cheese), while 49 were isolated directly from nine commercial cultures. The bacteria belonged to the genera Lactobacillus, Lactococcus, Leuconostoc and Streptococcus. Only one of the 189 isolates was classified as resistant to an antimicrobial agent included in the study. This isolate, a lactobacillus, was classified as high level resistant to streptomycin. The remaining isolates were not classified as resistant to the antimicrobial agents included other than to those they are known to have a natural reduced susceptibility to. Thus, starter culture bacteria in Norwegian dairy products do not seem to represent a source for spread of genes encoding resistance to antimicrobial agents.

Motility of electric cable bacteria

DEFF Research Database (Denmark)

Bjerg, Jesper Tataru; Damgaard, Lars Riis; Holm, Simon Agner

2016-01-01

Cable bacteria are filamentous bacteria that electrically couple sulfide oxidation and oxygen reduction at centimeter distances, and observations in sediment environments have suggested that they are motile. By time-lapse microscopy, we found that cable bacteria used gliding motility on surfaces...... with a highly variable speed of 0.50.3 ms1 (meanstandard deviation) and time between reversals of 155108 s. They frequently moved forward in loops, and formation of twisted loops revealed helical rotation of the filaments. Cable bacteria responded to chemical gradients in their environment, and around the oxic......-anoxic interface, they curled and piled up, with straight parts connecting back to the source of sulfide. Thus, it appears that motility serves the cable bacteria in establishing and keeping optimal connections between their distant electron donor and acceptors in a dynamic sediment environment....

Fermentation of D-Tagatose by Human Intestinal Bacteria and Dairy Lactic Acid Bacteria

OpenAIRE

Bertelsen, Hans; Andersen, Hans; Tvede, Michael

2011-01-01

A number of 174 normal or pathogenic human enteric bacteria and dairy lactic acid bacteria were screened for D-tagatose fermentation by incubation for 48 hours. Selection criteria for fermentation employed included a drop in pH below 5.5 and a distance to controls of more than 0.5. Only a few of the normal occurring enteric human bacteria were able to ferment D-tagatose, among those Enterococcus faecalis, Enterococcus faecium and Lactobacillus strains. D-Tagatose fermentation seems to be comm...

Interacción bacteria-microalga en el ambiente marino y uso potencial en acuicultura Microalgae and bacteria interaction in the aquatic environment and their potential use in aquaculture

Directory of Open Access Journals (Sweden)

CARLOS E. RIQUELME

2003-12-01

Full Text Available El presente estudio tiene como objetivo revisar el conocimiento generado sobre el rol que juegan las interacciones bacteria-microalga en ambientes marinos y dulceacuícolas, definiendo las posibles aplicaciones que puede tener el conocimiento de estas interacciones en el manejo de las aguas costeras y sistemas acuícolas. Los antecedentes proporcionados en este análisis permiten sugerir que bacterias y/o microalgas, constituyen una alternativa para el control de proliferaciones de bacterias y fitoplancton causantes de efectos dañinos en ambientes naturales y sistemas cerrados de cultivo. Además, las interacciones específicas entre bacteria-microalga permitiría la optimización de sistemas productivos en la industria acuícola. Sin embargo, los mecanismos de estas interacciones son pobremente entendidos. Futuras investigaciones debieran ser dirigidas a comprender el modo de acción de las interacciones bacteria-microalga a nivel molecularThe objective of this survey is to review the knowledge generated with respect to the role of bacteria-microalgae interaction play in marine and fresh environments, and to define the possible application of these microorganisms on the management of costal water and aquaculture systems. This review proposes that bacteria and/or microalgae are an alternative to control the proliferation of bacteria and phytoplankton that cause damages in natural environments or in closed culture systems. Also, the knowledge of specific interactions between bacteria and microalgae will allow the optimization of productive systems in aquaculture. However, until date the mechanisms involved in these interactions are poorly understood. Therefore, future investigations should be directed towards understanding the mode of action of such interactions at a molecular level

METHODS FOR DETECTING BACTERIA USING POLYMER MATERIALS

NARCIS (Netherlands)

Van Grinsven Bart Robert, Nicolaas; Cleij, Thomas

2017-01-01

A method for characterizing bacteria includes passing a liquid containing an analyte comprising a first bacteria and a second bacteria over and in contact with a polymer material on a substrate. The polymer material is formulated to bind to the first bacteria, and the first bacteria binds to the

Differentiation between spore-forming and asporogenic bacteria using a PCR and southern hybridization based method

Energy Technology Data Exchange (ETDEWEB)

Brill, J.A.; Wiegel, J. [Univ. of Georgia, Athens, GA (United States)

1997-12-31

A set of molecular probes was devised to develop a method for screening for the presence of sequences homologous to three representative genes exclusively involved in endosporulation. Based on known gene sequences, degenerate PCR primers were designed against spo0A and ssp. Experimental conditions were devised under which homologs of both genes were consistently detected in endospore-forming bacteria, but not in asporogenic bacteria. The PCR amplification products and dpaA/B from Bacillus subtilis were used as hybridization probes for Southern blots. Identical conditions were used with the genomic DNA from endospore-forming and asporogenic bacteria. We therefore concluded that the probes specifically detect the targeted sporulation genes and we obtained no indication that genes homologous to ssp, spo0A and dpaA/B are present in asporogenic bacteria. Thus, this assay can potentially be used to detect spore-forming bacteria in various kinds of samples and to distinguish between bacteria containing sporulation genes and those who do not regardless of whether sporulation is observed or not. 43 refs., 3 figs., 1 tab.

Antimicrobial Resistance and Resistance Genes in Aerobic Bacteria Isolated from Pork at Slaughter

DEFF Research Database (Denmark)

Li, Lili; Olsen, Rikke Heidemann; Ye, Lei

2016-01-01

The aim of this study was to investigate the phenotypic and genotypic antimicrobial resistance, integrons, and transferability of resistance markers in 243 aerobic bacteria recovered from pork at slaughter in the People's Republic of China. The organisms belonged to 22 genera of gram-negative bac......The aim of this study was to investigate the phenotypic and genotypic antimicrobial resistance, integrons, and transferability of resistance markers in 243 aerobic bacteria recovered from pork at slaughter in the People's Republic of China. The organisms belonged to 22 genera of gram......-negative bacteria (92.2%) and gram-positive bacteria (7.8%). High levels of resistance were detected to tetracycline, trimethoprim-sulfamethoxazole, and ampicillin (36.2 to 54.3%), and lower levels were detected to nitrofurantoin, cefotaxime, gentamicin, ciprofloxacin, and chloramphenicol (7.8 to 29.2%). Across.......6% of isolates contained class 1 integrons, and one isolate harbored class 2 integrons. Plasmid associated intI1 and androgen receptor– encoding genes were transferred into Escherichia coli J53 and E. coli DH5α by conjugation and transformation experiments, respectively. Our study highlights the importance...

Bioretention column study of bacteria community response to salt-enriched artificial stormwater.

Science.gov (United States)

Endreny, Theodore; Burke, David J; Burchhardt, Kathleen M; Fabian, Mark W; Kretzer, Annette M

2012-01-01

Cold climate cities with green infrastructure depend on soil bacteria to remove nutrients from road salt-enriched stormwater. Our research examined how bacterial communities in laboratory columns containing bioretention media responded to varying concentrations of salt exposure from artificial stormwater and the effect of bacteria and salt on column effluent concentrations. We used a factorial design with two bacteria treatments (sterile, nonsterile) and three salt concentrations (935, 315, and 80 ppm), including a deionized water control. Columns were repeatedly saturated with stormwater or deionized and then drained throughout 5 wk, with the last week of effluent analyzed for water chemistry. To examine bacterial communities, we extracted DNA from column bioretention media at time 0 and at week 5 and used molecular profiling techniques to examine bacterial community changes. We found that bacterial community taxa changed between time 0 and week 5 and that there was significant separation between taxa among salt treatments. Bacteria evenness was significantly affected by stormwater treatment, but there were no differences in bacterial richness or diversity. Soil bacteria and salt treatments had a significant effect on the effluent concentration of NO, PO, Cu, Pb, and Zn based on ANOVA tests. The presence of bacteria reduced effluent NO and Zn concentrations by as much as 150 and 25%, respectively, while having a mixed effect on effluent PO concentrations. Our results demonstrate how stormwater can affect bacterial communities and how the presence of soil bacteria improves pollutant removal by green infrastructure. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Use of tritium-labeled PCBs for investigation of PCBs biodegradation by soil bacteria

International Nuclear Information System (INIS)

Kim, A.A.; Djuraeva, G.T.; Takhtobiri, K.S.; Yadgarov, H.T.; Zinovev, P. V.; Abdukarimov, A.A.

2002-01-01

The method for tritium labelling of polychlorinated biphenyls (PCBs) was developed. The strains of soil bacteria - destructors of chloro organic compounds was studied with the help of test-system based on the using of tritium-labeled PCBs. The strains of bacteria were grown on the agar synthetic medium and then were introduced into the synthetic medium containing tritium-labeled mixture of PCBs (commercial mark - SOVOL) as alone source of carbon. The samples were analysed after one and two months period of incubation. PCBs were extracted by hexane from fraction of bacteria and fraction of cultural medium and radioactivity was measured. The samples were analyzed by thin layer chromatography (TLC) with following radioautography. Additionally samples were analyzed by gas chromatography. It was found that all selected strains survived in the medium with PCBs as alone source of carbon and bacteria accumulated PCBs from cultural medium. Accumulation of PCBs by strains of bacteria was different. The TLC analysis detected additional compounds labeled by tritium, that prove the degradation of PCBs in presence of bacteria. The gas chromatography analysis of cultural medium and bacteria detected redistribution in the system and qualitative changes of PCBs in bacteria. The strains of bacteria also were grown in model condition on the soil with tritium labeled PCBs. We found that some strains effectively destroy PCBs with decreasing level of tritium label in the soil. The using of tritium labeled PCBs' allows to introduce precise quantitative characteristics for study of accumulation and biodegradation PCBs by soil bacteria strains. Developed test-system is very useful tool for selection of new strains of soil bacteria - destructors of PCBs

Preliminary Safety Design Report for Remote Handled Low-Level Waste Disposal Facility

Energy Technology Data Exchange (ETDEWEB)

Timothy Solack; Carol Mason

2012-03-01

A new onsite, remote-handled low-level waste disposal facility has been identified as the highest ranked alternative for providing continued, uninterrupted remote-handled low-level waste disposal for remote-handled low-level waste from the Idaho National Laboratory and for nuclear fuel processing activities at the Naval Reactors Facility. Historically, this type of waste has been disposed of at the Radioactive Waste Management Complex. Disposal of remote-handled low-level waste in concrete disposal vaults at the Radioactive Waste Management Complex will continue until the facility is full or until it must be closed in preparation for final remediation of the Subsurface Disposal Area (approximately at the end of Fiscal Year 2017). This preliminary safety design report supports the design of a proposed onsite remote-handled low-level waste disposal facility by providing an initial nuclear facility hazard categorization, by discussing site characteristics that impact accident analysis, by providing the facility and process information necessary to support the hazard analysis, by identifying and evaluating potential hazards for processes associated with onsite handling and disposal of remote-handled low-level waste, and by discussing the need for safety features that will become part of the facility design.

Sulfur metabolism in phototrophic sulfur bacteria

DEFF Research Database (Denmark)

Frigaard, Niels-Ulrik; Dahl, Christiane

2008-01-01

Phototrophic sulfur bacteria are characterized by oxidizing various inorganic sulfur compounds for use as electron donors in carbon dioxide fixation during anoxygenic photosynthetic growth. These bacteria are divided into the purple sulfur bacteria (PSB) and the green sulfur bacteria (GSB......). They utilize various combinations of sulfide, elemental sulfur, and thiosulfate and sometimes also ferrous iron and hydrogen as electron donors. This review focuses on the dissimilatory and assimilatory metabolism of inorganic sulfur compounds in these bacteria and also briefly discusses these metabolisms...... in other types of anoxygenic phototrophic bacteria. The biochemistry and genetics of sulfur compound oxidation in PSB and GSB are described in detail. A variety of enzymes catalyzing sulfur oxidation reactions have been isolated from GSB and PSB (especially Allochromatium vinosum, a representative...

The endogenous bacteria alter gut epithelial apoptosis and decrease mortality following Pseudomonas aeruginosa pneumonia.

Science.gov (United States)

Fox, Amy C; McConnell, Kevin W; Yoseph, Benyam P; Breed, Elise; Liang, Zhe; Clark, Andrew T; O'Donnell, David; Zee-Cheng, Brendan; Jung, Enjae; Dominguez, Jessica A; Dunne, W Michael; Burd, Eileen M; Coopersmith, Craig M

2012-11-01

The endogenous bacteria have been hypothesized to play a significant role in the pathophysiology of critical illness, although their role in sepsis is poorly understood. The purpose of this study was to determine how commensal bacteria alter the host response to sepsis. Conventional and germ-free (GF) C57Bl/6 mice were subjected to Pseudomonas aeruginosa pneumonia. All GF mice died within 2 days, whereas 44% of conventional mice survived for 7 days (P = 0.001). Diluting the dose of bacteria 10-fold in GF mice led to similar survival in GF and conventional mice. When animals with similar mortality were assayed for intestinal integrity, GF mice had lower levels of intestinal epithelial apoptosis but similar levels of proliferation and intestinal permeability. Germ-free mice had significantly lower levels of tumor necrosis factor and interleukin 1β in bronchoalveolar lavage fluid compared with conventional mice without changes in systemic cytokine production. Under conventional conditions, sepsis unmasks lymphocyte control of intestinal epithelial apoptosis, because sepsis induces a greater increase in gut apoptosis in Rag-1 mice than in wild-type mice. However, in a separate set of experiments, gut apoptosis was similar between septic GF Rag-1 mice and septic GF wild-type mice. These data demonstrate that the endogenous bacteria play a protective role in mediating mortality from pneumonia-induced sepsis, potentially mediated through altered intestinal apoptosis and the local proinflammatory response. In addition, sepsis-induced lymphocyte-dependent increases in gut epithelial apoptosis appear to be mediated by the endogenous bacteria.

Effect of compliance during periodontal maintenance therapy on levels of bacteria associated with periodontitis: A 6-year prospective study.

Science.gov (United States)

Costa, Fernando Oliveira; Vieira, Thaís Riberal; Cortelli, Sheila Cavalca; Cota, Luís Otávio Miranda; Costa, José Eustáquio; Aguiar, Maria Cássia Ferreira; Cortelli, José Roberto

2018-05-01

It is well established that regular compliance during periodontal maintenance therapy (PMT) maintains the stability of periodontal clinical parameters obtained after active periodontal therapy (APT). However, compliance during PMT has not yet been related to subgingival bacterial levels. Thus, this study followed individuals in PMT over 6 years and longitudinally evaluated the effects of compliance on periodontitis-associated bacterial levels and its relation to periodontal status. From a 6-year prospective cohort study with 212 individuals in PMT, 91 were determined to be eligible. From this total, 28 regular compliers (RC) were randomly selected and matched for age and sex with 28 irregular compliers (IC). Complete periodontal examination and microbiological samples were obtained 5 times: T1 (prior to APT), T2 (after APT), T3 (2 years), T4 (4 years), and T5 (6 years). Total bacteria counts and levels of Actinomyces naeslundii, Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola were evaluated through quantitative polymerase chain reaction. RC had less tooth loss and better clinical and microbiological conditions over time when compared with IC. IC had higher total bacterial counts and higher levels of T. denticola. Moreover, among IC, total bacterial counts were positively associated with plaque index and bleeding on probing, while levels of A. naeslundii, T. forsythia, and T. denticola were negatively associated with clinical attachment loss (4 to 5 mm) among RC. Compliance positively influenced subgingival microbiota and contributed to stability of periodontal clinical status. Regular visits during PMT sustained microbiological benefits provided by APT over a 6-year period. © 2018 American Academy of Periodontology.

Radiobiological effects of heavy ions and protons. [on cells of mammals, bacteria and viruses

Science.gov (United States)

Ryzhov, N. I.; Vorozhtsova, S. V.; Krasavin, Y. A.; Mashinskaya, T. Y.; Savchenko, N. Y.; Fedorov, B. S.; Khlaponina, V. F.; Shelegedin, V. N.; Gut, L.; Sabo, L.

1974-01-01

Radiobiological effects of heavy ions and protons are studied on cells of mammals, bacteria, viruses and DNA of bacteria. Results show that the dose effect dependence bears an exponential character; the reduction of RBE as LET of particle increases reflects the different character of microdistribution of absorbed energy in biological objects with different levels of biological organization.

Hit-and-run, hit-and-stay, and commensal bacteria present different peptide content when viewed from the perspective of the T cell.

Science.gov (United States)

He, Lu; De Groot, Anne S; Bailey-Kellogg, Chris

2015-11-27

Different types of bacteria face different pressures from the immune system, with those that persist ("hit-and-stay") potentially having to adapt more in order to escape than those prone to short-lived infection ("hit-and-run"), and with commensal bacteria potentially different from both due to additional physical mechanisms for avoiding immune detection. The Janus Immunogenicity Score (JIS) was recently developed to assess the likelihood of T cell recognition of an antigen, using an analysis that considers both binding of a peptide within the antigen by major histocompatability complex (MHC) and recognition of the peptide:MHC complex by cognate T cell receptor (TCR). This score was shown to be predictive of T effector vs. T regulatory or null responses in experimental data, as well as to distinguish viruses representative of the hit-and-stay vs. hit-and-run phenotypes. Here, JIS-based analyses were conducted in order to characterize the extent to which the pressure to avoid T cell recognition is manifested in genomic differences among representative hit-and-run, hit-and-stay, and commensal bacteria. Overall, extracellular proteins were found to have different JIS profiles from cytoplasmic ones. Contrasting the bacterial groups, extracellular proteins were shown to be quite different across the groups, much more so than intracellular proteins. The differences were evident even at the level of corresponding peptides in homologous protein pairs from hit-and-run and hit-and-stay bacteria. The multi-level analysis of patterns of immunogenicity across different groups of bacteria provides a new way to approach questions of bacterial immune camouflage or escape, as well as to approach the selection and optimization of candidates for vaccine design. Copyright © 2015 Elsevier Ltd. All rights reserved.

Partial Purification, Characterization and Application of Bacteriocin from Bacteria Isolated Parkia biglobosa Seeds

Directory of Open Access Journals (Sweden)

Olorunjuwon O. Bello

2018-05-01

Full Text Available Bacteriocins are proteinaceous toxins produced by bacteria to inhibit the growth of similar or closely related bacterial strains. Fermented Parkia biglobosa seeds (African locust bean were screened for bacteriocin-producing lactic acid bacteria (LAB with the characterization of putative bacteriocins. Bacteriocin-producing lactic acid bacteria (LAB were identified by 16s rDNA sequencing. Molecular sizes of the bacteriocins were determined using the tricine-sodium dodecyl sulphate-polyacrylamide gel electrophoresis (tricine-SDS–PAGE and effects of enzymes, pH, detergents and temperature on bacteriocin activity investigated, using standard procedures. Bacteriocins production and activities were measured by spectrophotometric analysis. Statistical analysis was carried out using student t-test and Analyses of Variance. Bacteriocigenic LAB isolated were Lactobacillus plantarum Z1116, Enterococcus faecium AU02 and Leuconostoc lactis PKT0003. They inhibited the growth of both Gram-positive and Gram-negative bacteria. The sizes of bacteriocins Z1116, AU02 and PKT0003 were 3.2 kDa, 10 kDa and 10 kDa, respectively. The synergistic effects of characterized bacteriocins and rifampicin tested on organisms showed significant differences (P < 0.05, as compared with the effects of only one of the two. The antimicrobial activity of the three bacteriocins was deactivated after treatment of the cell-free supernatants with proteinase K, papain, pepsin and trypsin. Parkia biglobosa seeds are, therefore, rich in LAB bacteriocins which could be explored. The biosynthetic mechanisms of LAB bacteriocins could be employed in food safety and security, preservation, peptide design, infection control and pharmacotherapy. This should help in the control of undesirable bacteria and in designing more potent and selective antimicrobial peptides.

Dynamics of pollution-indicator and heterotrophic bacteria in sewage treatment lagoons.

Science.gov (United States)

Legendre, P; Baleux, B; Troussellier, M

1984-09-01

The spatio-temporal dynamics of pollution-indicator bacteria and aerobic heterotrophic bacteria were studied in the sewage treatment lagoons of an urban wastewater center after 26 months of biweekly sampling at eight stations in these lagoons. Robust statistical methods of time-series analysis were used to study successional steps (through chronological clustering) and rhythmic behavior through time (through contingency periodogram). The aerobic heterotrophic bacterial community showed two types of temporal evolution: in the first four stations, it seems mainly controlled by the nutrient support capacity of the sewage input, whereas in the remaining part of the lagoon, it seems likely that the pollution-indicator bacteria are gradually replaced by other bacterial types that are better adapted to this environment. On the other hand, the pollution-indicator bacteria showed an annual cycle which increased in amplitude at distances further from the wastewater source. The main events in this cycle were produced simultaneously at all stations, indicating control of these bacterial populations by climatic factors, which act through physical and chemical factors, and also through other biological components of this ecosystem (phytoplankton and zooplankton). Finally, we use results from this study to suggest a modified design for a future study program.

INOCULATION OF DIAZOTROPHIC BACTERIA AND NITROGEN FERTILIZATION IN TOPDRESSING IN IRRIGATED CORN

Directory of Open Access Journals (Sweden)

VANESSA ZIRONDI LONGHINI

2016-01-01

Full Text Available Corn is a nitrogen-intensive crop, and the use of management practices such as inoculation of the seed with diazotrophic bacteria, which can maximize crop productivity and reduce the need of nitrogen fertilizers, may result in lower production costs. The present study aimed to evaluate the effect of inoculation of corn seed with Azospirillum brasilense and controlled addition of nitrogen to topdressing on the nutrition, production components, and productivity of crop grain. The experimental design was a randomized block design, with four replications in a 2 × 5 factorial scheme. The treatments consisted of inoculation or not of corn seed with A. brasilense (at 100 mL per 25 kg of seed and five nitrogen (N levels in topdressing (0, 30, 60, 90, and 120 kg N ha-1 from urea [45% N] were applied when the corn was in the phenological growth stage V6. Foliar macronutrients, foliar chlorophyll index (FCI, production components, and yield of corn grain were valuated. Inoculation of corn seeds with A. brasilense increased plant height and grain yield. Fertilization in topdressing, with N levels up to 120 kg ha-1, linearly increased the foliar nutrients and productivity of corn cultivated in the spring/summer in the low-altitude Cerrado region of Brazil.

Optimum Safety Levels and Design Rules for the Icelandic Type Berm Breakwater

DEFF Research Database (Denmark)

Sigurdarson, Sigurdur; van der Meer, Jentsje W.; Burcharth, Hans F.

2007-01-01

Guidance on selection of breakwater types and related design safety levels for breakwaters are almost non-existent, which is the reason that PIANC has initiated working group 47 on this subject. This paper presents ongoing work particulary on the Icelandic type berm breakwater within the PIANC...... working group. It will concentrate on design guidance and on the optimum safety levels for this type of structure....

Isolation and Presumptive Identification of Adherent Epithelial Bacteria (“Epimural” Bacteria) from the Ovine Rumen Wall

OpenAIRE

Mead, Lorna J.; Jones, G. A.

1981-01-01

One hundred sixty-one strains of adherent bacteria were isolated under anaerobic conditions from four sites on the rumen epithelial surface of sheep fed hay or a hay-grain ration. Before isolation of bacteria, rumen tissue was washed six times in an anaerobic dilution solution, and viable bacteria suspended in the washings were counted. Calculation indicated that unattached bacteria would have been removed from the tissue by this procedure, but a slow and progressive release of attached bacte...

Re-engineering bacteria for ethanol production

Science.gov (United States)

Yomano, Lorraine P; York, Sean W; Zhou, Shengde; Shanmugam, Keelnatham; Ingram, Lonnie O

2014-05-06

The invention provides recombinant bacteria, which comprise a full complement of heterologous ethanol production genes. Expression of the full complement of heterologous ethanol production genes causes the recombinant bacteria to produce ethanol as the primary fermentation product when grown in mineral salts medium, without the addition of complex nutrients. Methods for producing the recombinant bacteria and methods for producing ethanol using the recombinant bacteria are also disclosed.

Oligotrophic bacteria isolated from clinical materials.

OpenAIRE

Tada, Y; Ihmori, M; Yamaguchi, J

1995-01-01

Oligotrophic bacteria (oligotrophs) are microorganisms that grow in extremely nutritionally deficient conditions in which the concentrations of organic substances are low. Many oligotrophic bacteria were isolated from clinical materials including urine, sputum, swabbings of the throat, vaginal discharges, and others. Seventy-seven strains of oligotrophic bacteria from 871 samples of clinical material were isolated. A relatively higher frequency of isolation of oligotrophic bacteria was shown ...

Requirements for high level models supporting design space exploration in model-based systems engineering

NARCIS (Netherlands)

Haveman, Steven; Bonnema, Gerrit Maarten

2013-01-01

Most formal models are used in detailed design and focus on a single domain. Few effective approaches exist that can effectively tie these lower level models to a high level system model during design space exploration. This complicates the validation of high level system requirements during

Seeing green bacteria in a new light: genomics-enabled studies of the photosynthetic apparatus in green sulfur bacteria and filamentous anoxygenic phototrophic bacteria

DEFF Research Database (Denmark)

Frigaard, Niels-Ulrik; Bryant, Donald A

2004-01-01

Based upon their photosynthetic nature and the presence of a unique light-harvesting antenna structure, the chlorosome, the photosynthetic green bacteria are defined as a distinctive group in the Bacteria. However, members of the two taxa that comprise this group, the green sulfur bacteria...... (Chlorobi) and the filamentous anoxygenic phototrophic bacteria ("Chloroflexales"), are otherwise quite different, both physiologically and phylogenetically. This review summarizes how genome sequence information facilitated studies of the biosynthesis and function of the photosynthetic apparatus...... a and carotenoid biosynthesis enzymes, gene cluster analysis in Cfx. aurantiacus, and gene inactivation studies in Chl. tepidum. Based on these results, BChl a and BChl c biosynthesis is similar in the two organisms, whereas carotenoid biosynthesis differs significantly. In agreement with its facultative anaerobic...

NASA: A generic infrastructure for system-level MP-SoC design space exploration

NARCIS (Netherlands)

Jia, Z.J.; Pimentel, A.D.; Thompson, M.; Bautista, T.; Núñez, A.

2010-01-01

System-level simulation and design space exploration (DSE) are key ingredients for the design of multiprocessor system-on-chip (MP-SoC) based embedded systems. The efforts in this area, however, typically use ad-hoc software infrastructures to facilitate and support the system-level DSE experiments.

Design and construction of the low-level liquid waste treatment system

International Nuclear Information System (INIS)

Baker, M.N.; Mateer, W.E.; Metzler, G.H.; Reeves, S.R.; Rickettson, D.J.

1989-03-01

This report describes the design and construction of the Low-Level Liquid Waste Treatment System (LWTS). The LWTS is part of a system that will prepare High-Level Radioactive Waste for solidification in glass. This preparation includes removal of water and salts from the stored waste. The topics addressed are: the design objective to reuse the Process Building to contain LWTS, the special considerations that arise when building a new system inside a decontaminated facility, interface to existing plant systems, phased construction, and construction testing. 8 refs., 24 figs

How honey kills bacteria

NARCIS (Netherlands)

Kwakman, Paulus H. S.; te Velde, Anje A.; de Boer, Leonie; Speijer, Dave; Vandenbroucke-Grauls, Christina M. J. E.; Zaat, Sebastian A. J.

2010-01-01

With the rise in prevalence of antibiotic-resistant bacteria, honey is increasingly valued for its antibacterial activity. To characterize all bactericidal factors in a medical-grade honey, we used a novel approach of successive neutralization of individual honey bactericidal factors. All bacteria

Association of metal tolerance with multiple antibiotic resistance of bacteria isolated from drinking water.

Science.gov (United States)

Calomiris, J J; Armstrong, J L; Seidler, R J

1984-06-01

Bacterial isolates from the drinking water system of an Oregon coastal community were examined to assess the association of metal tolerance with multiple antibiotic resistance. Positive correlations between tolerance to high levels of Cu2+, Pb2+, and Zn2+ and multiple antibiotic resistance were noted among bacteria from distribution waters but not among bacteria from raw waters. Tolerances to higher levels of Al3+ and Sn2+ were demonstrated more often by raw water isolates which were not typically multiple antibiotic resistant. A similar incidence of tolerance to Cd2+ was demonstrated by isolates of both water types and was not associated with multiple antibiotic resistance. These results suggest that simultaneous selection phenomena occurred in distribution water for bacteria which exhibited unique patterns of tolerance to Cu2+, Pb2+, and Zn2+ and antibiotic resistance.

Pathogenic Assay of Probiotic Bacteria Producing Proteolytic Enzymes as Bioremediation Bacteria Against Vannamei Shrimp Larvae (Litopenaeus vannamei

Directory of Open Access Journals (Sweden)

Wilis Ari Setyati

2017-06-01

Full Text Available Application of bacteria in bioremediation of shrimp culture ponds is one of the methods used to clean internal pollutants. This study aimed to evaluate the pathogenicity of extracellular proteolytic enzyme produced by the probiotic bacteria as bioremediation bacteria on vannamei shrimp larvae culture. There were five probiotic bacteria, which were successfully isolated from the sediments served as substrate in mangrove area. The isolated bacteria were coded in number as 13, 19, 30, 33, and 36. Pathogenic bacteria Vibrio harveyi was used as positive control. Pathogenic assay was carried out in two different bacterial concentrations, i.e. 10⁸ and 10⁶ cells.mL-1. The results showed that the lowest survival rate (SR of shrimp larvae in positive control V. harveyi was 53 and 65%. Whereas isolates with the highest SR value (100% were obtained from bacteria coded as 13 and 30. Isolates no. 19, 33 and 36 had SR of more than 90%. Total plate count (TPC data showed that the bacteria increased significantly at the end of the study with an average increase value of 24%. The smallest TPC value was shown by bacterial isolate no. 19, while the largest was obtained from the isolate no. 13. These results suggest that all probiotic bacteria were not pathogenic to the vannamei shrimp larvae.   Keywords: aquaculture, shrimp, bioremediation, pathogenesis, vibrio.

Isolation and identification of local bacteria endophyte and screening of its antimicrobial property against pathogenic bacteria and fungi

Science.gov (United States)

Fikri, Ahmad Syairazie Ibrahim; Rahman, Irman Abdul; Nor, Norefrina Shafinaz Md; Hamzah, Ainon

2018-04-01

Endophytes are organisms, often fungi and bacteria that live in living plant cells. These organisms reside in the living tissues of the host plant in a variety of relationships, ranging from symbiotic to slightly pathogenic. The endophytes may produce a plethora of substances that have potential to be used in modern medicine, agriculture and industry. The aims of this study are to isolate, identify and screening antimicrobial activity of bacterial endophytes. The endophytes were isolated using nutrient agar, incubated at 37°C for 48 hours. Identification of the isolates were done based on morphological characteristics, biochemical tests and 16S rDNA molecular analysis. Disk diffusion method was used to screen for antimicrobial activity of metabolites from endophytes against pathogenic bacteria. Screening for antifungal activity of selected endophytes was done using dual culture method againts pathogenic fungi followed by Kirby-Bauer method. Results showed endophytes designated as B2c and B7b have positive antimicrobial activity. The metabolites from isolate B2c showed antimicrobial activity against pathogenic bacteria methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus aureus and Staphylococcus epidermis, while isolate B7b have positive activities againts MRSA, S. aureus and Pseudomonas aeruginosa. Isolates B2c displayed antifungal activity against Fusarium oxysporum, Fusarium solani, Phytophthora palmivora and Colletotrichum gloeosporioides. Identification using biochemical tests and 16S rDNA sequences identified isolate B2c as Pseudomonas resinovorans with 97% homology and isolate B7b as Bacillus subtilis with 98% homology.

Grazing of particle-associated bacteria-an elimination of the non-viable fraction.

Science.gov (United States)

Gonsalves, Maria-Judith; Fernandes, Sheryl Oliveira; Priya, Madasamy Lakshmi; LokaBharathi, Ponnapakkam Adikesavan

Quantification of bacteria being grazed by microzooplankton is gaining importance since they serve as energy subsidies for higher trophic levels which consequently influence fish production. Hence, grazing pressure on viable and non-viable fraction of free and particle-associated bacteria in a tropical estuary controlled mainly by protist grazers was estimated using the seawater dilution technique. In vitro incubations over a period of 42h showed that at the end of 24h, growth coefficient (k) of particle-associated bacteria was 9 times higher at 0.546 than that of free forms. Further, 'k' value of viable cells on particles was double that of free forms at 0.016 and 0.007, respectively. While bacteria associated with particles were grazed (coefficient of removal (g)=0.564), the free forms were relatively less grazed indicating that particle-associated bacteria were exposed to grazers in these waters. Among the viable and non-viable forms, 'g' of non-viable fraction (particle-associated bacteria=0.615, Free=0.0086) was much greater than the viable fraction (particle-associated bacteria=0.056, Free=0.068). Thus, grazing on viable cells was relatively low in both the free and attached states. These observations suggest that non-viable forms of particle-associated bacteria were more prone to grazing and were weeded out leaving the viable cells to replenish the bacterial standing stock. Particle colonization could thus be a temporary refuge for the "persistent variants" where the viable fraction multiply and release their progeny. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

Grazing of particle-associated bacteria-an elimination of the non-viable fraction

Directory of Open Access Journals (Sweden)

Maria-Judith Gonsalves

Full Text Available Abstract Quantification of bacteria being grazed by microzooplankton is gaining importance since they serve as energy subsidies for higher trophic levels which consequently influence fish production. Hence, grazing pressure on viable and non-viable fraction of free and particle-associated bacteria in a tropical estuary controlled mainly by protist grazers was estimated using the seawater dilution technique. In vitro incubations over a period of 42 h showed that at the end of 24 h, growth coefficient (k of particle-associated bacteria was 9 times higher at 0.546 than that of free forms. Further, ‘k’ value of viable cells on particles was double that of free forms at 0.016 and 0.007, respectively. While bacteria associated with particles were grazed (coefficient of removal (g = 0.564, the free forms were relatively less grazed indicating that particle-associated bacteria were exposed to grazers in these waters. Among the viable and non-viable forms, ‘g’ of non-viable fraction (particle-associated bacteria = 0.615, Free = 0.0086 was much greater than the viable fraction (particle-associated bacteria = 0.056, Free = 0.068. Thus, grazing on viable cells was relatively low in both the free and attached states. These observations suggest that non-viable forms of particle-associated bacteria were more prone to grazing and were weeded out leaving the viable cells to replenish the bacterial standing stock. Particle colonization could thus be a temporary refuge for the “persistent variants” where the viable fraction multiply and release their progeny.

Magnesium and manganese content of halophilic bacteria

International Nuclear Information System (INIS)

de Medicis, E.; Paquette, J.; Gauthier, J.J.; Shapcott, D.

1986-01-01

Magnesium and manganese contents were measured by atomic absorption spectrophotometry in bacteria of several halophilic levels, in Vibrio costicola, a moderately halophilic eubacterium growing in 1 M NaCl, Halobacterium volcanii, a halophilic archaebacterium growing in 2.5 NaCl, Halobacterium cutirubrum, an extremely halophilic archaebacterium growing in 4 M NaCl, and Escherichia coli, a nonhalophilic eubacterium growing in 0.17 M NaCl. Magnesium and manganese contents varied with the growth phase, being maximal at the early log phase. Magnesium and manganese molalities in cell water were shown to increase with the halophilic character of the logarithmically growing bacteria, from 30 mmol of Mg per kg of cell water and 0.37 mmol of Mn per kg of cell water for E. coli to 102 mmol of Mg per kg of cell water and 1.6 mmol of Mn per kg of cell water for H cutirubrum. The intracellular concentrations of manganese were determined independently by a radioactive tracer technique in V. costicola and H. volcanii. The values obtained by 54 Mn loading represented about 70% of the values obtained by atomic absorption. The increase of magnesium and manganese contents associated with the halophilic character of the bacteria suggests that manganese and magnesium play a role in haloadaptation

Effect of air pollution on the total bacteria and pathogenic bacteria in different sizes of particulate matter.

Science.gov (United States)

Liu, Huan; Zhang, Xu; Zhang, Hao; Yao, Xiangwu; Zhou, Meng; Wang, Jiaqi; He, Zhanfei; Zhang, Huihui; Lou, Liping; Mao, Weihua; Zheng, Ping; Hu, Baolan

2018-02-01

In recent years, air pollution events have occurred frequently in China during the winter. Most studies have focused on the physical and chemical composition of polluted air. Some studies have examined the bacterial bioaerosols both indoors and outdoors. But few studies have focused on the relationship between air pollution and bacteria, especially pathogenic bacteria. Airborne PM samples with different diameters and different air quality index values were collected in Hangzhou, China from December 2014 to January 2015. High-throughput sequencing of 16S rRNA was used to categorize the airborne bacteria. Based on the NCBI database, the "Human Pathogen Database" was established, which is related to human health. Among all the PM samples, the diversity and concentration of total bacteria were lowest in the moderately or heavily polluted air. However, in the PM2.5 and PM10 samples, the relative abundances of pathogenic bacteria were highest in the heavily and moderately polluted air respectively. Considering the PM samples with different particle sizes, the diversities of total bacteria and the proportion of pathogenic bacteria in the PM10 samples were different from those in the PM2.5 and TSP samples. The composition of PM samples with different sizes range may be responsible for the variances. The relative humidity, carbon monoxide and ozone concentrations were the main factors, which affected the diversity of total bacteria and the proportion of pathogenic bacteria. Among the different environmental samples, the compositions of the total bacteria were very similar in all the airborne PM samples, but different from those in the water, surface soil, and ground dust samples. Which may be attributed to that the long-distance transport of the airflow may influence the composition of the airborne bacteria. This study of the pathogenic bacteria in airborne PM samples can provide a reference for environmental and public health researchers. Copyright © 2017 Elsevier Ltd

Design of megawatt power level heat pipe reactors

Energy Technology Data Exchange (ETDEWEB)

Mcclure, Patrick Ray [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Poston, David Irvin [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dasari, Venkateswara Rao [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Reid, Robert Stowers [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2015-11-12

An important niche for nuclear energy is the need for power at remote locations removed from a reliable electrical grid. Nuclear energy has potential applications at strategic defense locations, theaters of battle, remote communities, and emergency locations. With proper safeguards, a 1 to 10-MWe (megawatt electric) mobile reactor system could provide robust, self-contained, and long-term power in any environment. Heat pipe-cooled fast-spectrum nuclear reactors have been identified as a candidate for these applications. Heat pipe reactors, using alkali metal heat pipes, are perfectly suited for mobile applications because their nature is inherently simpler, smaller, and more reliable than “traditional” reactors. The goal of this project was to develop a scalable conceptual design for a compact reactor and to identify scaling issues for compact heat pipe cooled reactors in general. Toward this goal two detailed concepts were developed, the first concept with more conventional materials and a power of about 2 MWe and a the second concept with less conventional materials and a power level of about 5 MWe. A series of more qualitative advanced designs were developed (with less detail) that show power levels can be pushed to approximately 30 MWe.

Conceptual Design Report for the Remote-Handled Low-Level Waste Disposal Project

Energy Technology Data Exchange (ETDEWEB)

David Duncan

2011-05-01

This conceptual design report addresses development of replacement remote-handled low-level waste disposal capability for the Idaho National Laboratory. Current disposal capability at the Radioactive Waste Management Complex is planned until the facility is full or until it must be closed in preparation for final remediation (approximately at the end of Fiscal Year 2017). This conceptual design report includes key project assumptions; design options considered in development of the proposed onsite disposal facility (the highest ranked alternative for providing continued uninterrupted remote-handled low level waste disposal capability); process and facility descriptions; safety and environmental requirements that would apply to the proposed facility; and the proposed cost and schedule for funding, design, construction, and operation of the proposed onsite disposal facility.

Conceptual Design Report for the Remote-Handled Low-Level Waste Disposal Project

Energy Technology Data Exchange (ETDEWEB)

Lisa Harvego; David Duncan; Joan Connolly; Margaret Hinman; Charles Marcinkiewicz; Gary Mecham

2011-03-01

This conceptual design report addresses development of replacement remote-handled low-level waste disposal capability for the Idaho National Laboratory. Current disposal capability at the Radioactive Waste Management Complex is planned until the facility is full or until it must be closed in preparation for final remediation (approximately at the end of Fiscal Year 2017). This conceptual design report includes key project assumptions; design options considered in development of the proposed onsite disposal facility (the highest ranked alternative for providing continued uninterrupted remote-handled low level waste disposal capability); process and facility descriptions; safety and environmental requirements that would apply to the proposed facility; and the proposed cost and schedule for funding, design, construction, and operation of the proposed onsite disposal facility.

Lactic Acid Bacteria from Kefir Increase Cytotoxicity of Natural Killer Cells to Tumor Cells.

Science.gov (United States)

Yamane, Takuya; Sakamoto, Tatsuji; Nakagaki, Takenori; Nakano, Yoshihisa

2018-03-27

The Japanese fermented beverage, homemade kefir, contains six lactic acid bacteria: Lactococcus. lactis subsp. Lactis , Lactococcus . lactis subsp. Cremoris , Lactococcus. Lactis subsp. Lactis biovar diacetylactis , Lactobacillus plantarum , Leuconostoc meseuteroides subsp. Cremoris and Lactobacillus casei . In this study, we found that a mixture of the six lactic acid bacteria from kefir increased the cytotoxicity of human natural killer KHYG-1 cells to human chronic myelogenous leukemia K562 cells and colorectal tumor HCT116 cells. Furthermore, levels of mRNA expression and secretion of IFN-γ (interferon gamma) increased in KHYG-1 cells that had been treated with the six lactic acid bacteria mixture from kefir. The results suggest that the six lactic acid bacteria mixture from kefir has strong effects on natural immunity and tumor cell cytotoxicity.

Antibiotics from predatory bacteria

Directory of Open Access Journals (Sweden)

Juliane Korp

2016-03-01

Full Text Available Bacteria, which prey on other microorganisms, are commonly found in the environment. While some of these organisms act as solitary hunters, others band together in large consortia before they attack their prey. Anecdotal reports suggest that bacteria practicing such a wolfpack strategy utilize antibiotics as predatory weapons. Consistent with this hypothesis, genome sequencing revealed that these micropredators possess impressive capacities for natural product biosynthesis. Here, we will present the results from recent chemical investigations of this bacterial group, compare the biosynthetic potential with that of non-predatory bacteria and discuss the link between predation and secondary metabolism.

Temporal and Spatial Variation of Soil Bacteria Richness, Composition, and Function in a Neotropical Rainforest.

Science.gov (United States)

Kivlin, Stephanie N; Hawkes, Christine V

2016-01-01

The high diversity of tree species has traditionally been considered an important controller of belowground processes in tropical rainforests. However, soil water availability and resources are also primary regulators of soil bacteria in many ecosystems. Separating the effects of these biotic and abiotic factors in the tropics is challenging because of their high spatial and temporal heterogeneity. To determine the drivers of tropical soil bacteria, we examined tree species effects using experimental tree monocultures and secondary forests at La Selva Biological Station in Costa Rica. A randomized block design captured spatial variation and we sampled at four dates across two years to assess temporal variation. We measured bacteria richness, phylogenetic diversity, community composition, biomass, and functional potential. All bacteria parameters varied significantly across dates. In addition, bacteria richness and phylogenetic diversity were affected by the interaction of vegetation type and date, whereas bacteria community composition was affected by the interaction of vegetation type and block. Shifts in bacteria community richness and composition were unrelated to shifts in enzyme function, suggesting physiological overlap among taxa. Based on the observed temporal and spatial heterogeneity, our understanding of tropical soil bacteria will benefit from additional work to determine the optimal temporal and spatial scales for sampling. Understanding spatial and temporal variation will facilitate prediction of how tropical soil microbes will respond to future environmental change.

Biodegradation of Mixed PAHs by PAH-Degrading Endophytic Bacteria

Directory of Open Access Journals (Sweden)

Xuezhu Zhu

2016-08-01

Full Text Available Endophytic bacteria can promote plant growth, induce plant defence mechanisms, and increase plant resistance to organic contaminants. The aims of the present study were to isolate highly PAH-degrading endophytic bacteria from plants growing at PAH-contaminated sites and to evaluate the capabilities of these bacteria to degrade polycyclic aromatic hydrocarbons (PAHs in vitro, which will be beneficial for re-colonizing target plants and reducing plant PAH residues through the inoculation of plants with endophytic bacteria. Two endophytic bacterial strains P1 (Stenotrophomonas sp. and P3 (Pseudomonas sp., which degraded more than 90% of phenanthrene (PHE within 7 days, were isolated from Conyza canadensis and Trifolium pretense L., respectively. Both strains could use naphthalene (NAP, PHE, fluorene (FLR, pyrene (PYR, and benzo(apyrene (B(aP as the sole sources of carbon and energy. Moreover, these bacteria reduced the contamination of mixed PAHs at high levels after inoculation for 7 days; strain P1 degraded 98.0% NAP, 83.1% FLR, 87.8% PHE, 14.4% PYR, and 1.6% B(aP, and strain P3 degraded 95.3% NAP, 87.9% FLR, 90.4% PHE, 6.9% PYR, and negligible B(aP. Notably, the biodegradation of PAHs could be promoted through additional carbon and nitrogen nutrients; therein, beef extract was suggested as the optimal co-substrate for the degradation of PAHs by these two strains (99.1% PHE was degraded within 7 days. Compared with strain P1, strain P3 has more potential for the use in the removal of PAHs from plant tissues. These results provide a novel perspective in the reduction of plant PAH residues in PAH-contaminated sites through inoculating plants with highly PAH-degrading endophytic bacteria.

Characterization of specimens obtained by different sampling methods for evaluation of periodontal bacteria.

Science.gov (United States)

Okada, Ayako; Sogabe, Kaoru; Takeuchi, Hiroaki; Okamoto, Masaaki; Nomura, Yoshiaki; Hanada, Nobuhiro

2017-12-27

Quantitative analysis of periodontal bacteria is considered useful for clinical diagnosis, evaluation and assessment of the risk of periodontal disease. The purpose of this study was to compare the effectiveness of sampling of saliva, supragingival and subgingival plaque for evaluation of periodontal bacteria. From each of 12 subjects, i) subgingival plaque was collected from the deepest pocket using a sterile paper point, ii) stimulated whole saliva was collected after chewing gum, and iii) supragingival plaque was collected using a tooth brush. These samples were sent to the medical examination laboratory for quantitative analysis of the counts of three periodontal bacterial species: Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia. The proportions of these bacteria in subgingival plaque were higher than those in saliva or supragingival plaque, but lower in subgingival plaque than in saliva or supragingival plaque. In several cases, periodontal bacteria were below the levels of detection in subgingival plaque. We concluded that samples taken from subgingival plaque may be more useful for evaluating the proportion of periodontal bacteria in deep pockets than is the case for other samples. Therefore, for evaluation of periodontal bacteria, clinicians should consider the characteristics of the specimens obtained using different sampling methods.

Beer spoilage bacteria and hop resistance

NARCIS (Netherlands)

Sakamoto, K; Konings, WN

2003-01-01

For brewing industry, beer spoilage bacteria have been problematic for centuries. They include some lactic acid bacteria such as Lactobacillus brevis, Lactobacillus lindneri and Pediococcus damnosus, and some Gram-negative bacteria such as Pectinatus cerevisiiphilus, Pectinatus frisingensis and

The influence of subway station design on noise levels.

Science.gov (United States)

Shah, Ravi R; Suen, Jonathan J; Cellum, Ilana P; Spitzer, Jaclyn B; Lalwani, Anil K

2017-05-01

To investigate the impact of subway station design on platform noise levels. Observational. Continuous A-weighted decibel (dBA) sound levels were recorded in 20 New York City subway stations, where trains entered on either a straight track or curved track in 10 stations each. Equivalent continuous noise levels (L eq ) at various locations on the boarding platform (inbound end, midplatform, and outbound end) during train entry and exit were compared between the straight and curved stations in broadband as well as narrow one-third octave bands. Overall, curved stations trended louder than straight stations, although the difference in broadband L eq did not reach statistical significance (curve, 83.4 dBA; straight, 82.6 dBA; P = .054). Noise levels were significantly louder at the inbound end of the platform during train entry (inbound, 89.7 dBA; mid, 85.5 dBA; outbound, 78.7 dBA; P < .001) and at the outbound end during train exit (inbound, 79.7 dBA; mid, 85.3 dBA; outbound, 89.1 dBA; P < .001). Narrow band analysis showed that curved stations were significantly louder than straight stations at 100 Hz and high frequencies from 8 to 20 kHz. Peak impact levels ranged from 104 to 121 dBA. Curved stations have a different noise profile compared to straight stations and are significantly louder than straight stations at high frequencies. Designing stations with straight tracks within the platform can help reduce commuter noise exposure. NA Laryngoscope, 127:1169-1174, 2017. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.

A Probabilistic Approach for the System-Level Design of Multi-ASIP Platforms

DEFF Research Database (Denmark)

Micconi, Laura

introduce a system-level Design Space Exploration (DSE) for the very early phases of the design that automatizes part of the multi-ASIP design flow. Our DSE is responsible for assigning the tasks to the different ASIPs exploring different platform alternatives. We perform a schedulability analysis for each...

Association of red complex, A. actinomycetemcomitans and non-oral bacteria with periodontal diseases.

Science.gov (United States)

da Silva-Boghossian, Carina Maciel; do Souto, Renata Martins; Luiz, Ronir R; Colombo, Ana Paula Vieira

2011-09-01

Pathogens related to systemic infections have been detected in the periodontal microbiota. The relationship amongst these pathogens, periodontal bacteria and periodontal clinical status is poorly understood. This study evaluated the association amongst red complex, A. actinomycetemcomitans (A.a) and non-oral pathogenic bacteria in subjects with good periodontal health (PH), gingivitis (G), chronic (CP) and aggressive (AP) periodontitis. Subgingival biofilm samples were obtained from 51 PH, 42 G, 219 CP and 90 AP subjects. The presence and levels of A.a, red complex (Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola), Acinetobacter baumannii, Escherichia coli, Enterococcus faecalis, Pseudomonas aeruginosa, and Staphylococcus aureus were determined by DNA probes and DNA-DNA hybridization technique. CP and AP subjects presented significantly higher prevalence and levels of A.a, red complex and A. baumannii than G and PH individuals (pperiodontal disease (pperiodontal pathogens and non-oral bacteria alone or in association were strongly associated with periodontitis. Copyright © 2011 Elsevier Ltd. All rights reserved.

A Platform-Based Methodology for System-Level Mixed-Signal Design

Directory of Open Access Journals (Sweden)

Alberto Sangiovanni-Vincentelli

2010-01-01

Full Text Available The complexity of today's embedded electronic systems as well as their demanding performance and reliability requirements are such that their design can no longer be tackled with ad hoc techniques while still meeting tight time to-market constraints. In this paper, we present a system level design approach for electronic circuits, utilizing the platform-based design (PBD paradigm as the natural framework for mixed-domain design formalization. In PBD, a meet-in-the-middle approach allows systematic exploration of the design space through a series of top-down mapping of system constraints onto component feasibility models in a platform library, which is based on bottom-up characterizations. In this framework, new designs can be assembled from the precharacterized library components, giving the highest priority to design reuse, correct assembly, and efficient design flow from specifications to implementation. We apply concepts from design centering to enforce robustness to modeling errors as well as process, voltage, and temperature variations, which are currently plaguing embedded system design in deep-submicron technologies. The effectiveness of our methodology is finally shown on the design of a pipeline A/D converter and two receiver front-ends for UMTS and UWB communications.

Amniotic fluid protein profiles of intraamniotic inflammatory response to Ureaplasma spp. and other bacteria.

Directory of Open Access Journals (Sweden)

Marian Kacerovsky

Full Text Available OBJECTIVE: This study aimed to evaluate the amniotic fluid protein profiles and the intensity of intraamniotic inflammatory response to Ureaplasma spp. and other bacteria, using the multiplex xMAP technology. METHODS: A retrospective cohort study was undertaken in the Department of Obstetrics and Gynecology, University Hospital Hradec Kralove, Czech Republic. A total of 145 pregnant women with preterm prelabor rupture of membranes between gestational age 24+0 and 36+6 weeks were included in the study. Amniocenteses were performed. The presence of Ureaplasma spp. and other bacteria was evaluated using 16S rRNA gene sequencing. The levels of specific proteins were determined using multiplex xMAP technology. RESULTS: The presence of Ureaplasma spp. and other bacteria in the amniotic fluid was associated with increased levels of interleukin (IL-6, IL-8, IL-10, brain-derived neurotropic factor, granulocyte macrophage colony stimulating factor, monocyte chemotactic protein-1, macrophage inflammatory protein-1, and matrix metalloproteinasis-9. Ureaplasma spp. were also associated with increased levels of neurotropin-3 and triggering receptor expressed on myeloid cells-1. CONCLUSIONS: The presence of Ureaplasma spp. in the amniotic fluid is associated with a slightly different protein profile of inflammatory response, but the intensity of inflammatory response to Ureaplasma spp. is comparable with the inflammatory response to other bacteria.

Associative bacteria influence maize (Zea mays L.) growth, physiology and root anatomy under different nitrogen levels.

Science.gov (United States)

Calzavara, Anderson Kikuchi; Paiva, Pedro Henrique Godoy; Gabriel, Lorrant Cavanha; de Oliveira, André Luiz Martinez; Milani, Karina; Oliveira, Halley Caixeta; Bianchini, Edmilson; Pimenta, José Antonio; de Oliveira, Maria Cristina Neves; Dias-Pereira, Jaqueline; Stolf-Moreira, Renata

2018-05-15

Despite the great diversity of plant growth-promoting bacteria (PGPB) with potential to partially replace the use of N-fertilizers in agriculture, few PGPB are explored for the production of commercial inoculants, reinforcing the importance of identifying positive plant-bacteria interactions. Aiming to better understand the influence of PGPB inoculation in plant development, two PGPB species with distant phylogenetic relationship were inoculated in maize. Maize seeds were inoculated with Bacillus sp. or Azospirillum brasilense. After germinating, the plants were subjected to two nitrogen treatments: full (N+) and limiting (N-) nitrogen supply. Then, anatomical, biometric and physiological analyses were performed. Both PGPB species modified the anatomical pattern of roots, as verified by the higher metaxylem vessel elements (MVE) number. Bacillus sp. also increased the MVE area in maize roots. Under N+ condition, both PGPB decreased the leaf protein content and led to the development of shorter roots; however, Bacillus sp. increased root and shoot dry weight, whereas A. brasilense increased photosynthesis rate and leaf nitrate content. In plants subjected to N limitation (N-), photosynthesis rate and photosystem II efficiency increased in those inoculated with Bacillus sp., whilst A. brasilense led to higher ammonium, amino acids and total soluble sugars contents in the leaves, compared to control. Plant developmental and metabolical patterns were switched by the inoculation, regardless the inoculant bacteria used, producing similar as well as distinct modifications on the parameters studied. These results indicatie that even non-diazotrophic inoculant strains can improve the plant N-status as result of the morpho-anatomical and physiological modifications produced by the PGPB. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

assessment of fecal bacteria contamination in sewage and non ...

African Journals Online (AJOL)

Mgina

chemical parameters (temperature, pH, salinity and nutrients) were measured. ... Kijichi than Rasi Dege). No significant variation was noted on the values of temperature, pH and salinity. A significant correlation between the levels of fecal bacteria indicators and nutrient ... ocean e.g. sewage is discharged directly into.

Human body may produce bacteria.

Science.gov (United States)

Salerian, Alen J

2017-06-01

"Human body may produce bacteria" proposes that human body may produce bacteria and represent an independent source of infections contrary to the current paradigm of infectious disorders proposed by Louis Pasteur in 1880. The following observations are consistent with this hypothesis: A. Bidirectional transformations of both living and nonliving things have been commonly observed in nature. B. Complex multicellular organisms harbor the necessary properties to produce bacteria (water, nitrogen and oxygen). C. Physical laws suggest any previously observed phenomenon or action will occur again (life began on earth; a non living thing). D. Animal muscle cells may generate energy (fermentation). E. Sterilized food products (i.e. boiled eggs), may produce bacteria and fungus under special conditions and without any exposure to foreign living cells. "Human body may produce bacteria" may challenge the current medical paradigm that views human infectious disorders as the exclusive causative byproducts of invading foreign cells. It may also introduce new avenues to treat infectious disorders. Copyright © 2017 Elsevier Ltd. All rights reserved.

System-level modelling of dynamic reconfigurable designs using functional programming abstractions

NARCIS (Netherlands)

Uchevler, B.N.; Svarstad, Kjetil; Kuper, Jan; Baaij, C.P.R.

With the increasing size and complexity of designs in electronics, new approaches are required for the description and verification of digital circuits, specifically at the system level. Functional HDLs can appear as an advantageous choice for formal verification and high-level descriptions. In this

Characterization of airborne bacteria at an underground subway station.

Science.gov (United States)

Dybwad, Marius; Granum, Per Einar; Bruheim, Per; Blatny, Janet Martha

2012-03-01

The reliable detection of airborne biological threat agents depends on several factors, including the performance criteria of the detector and its operational environment. One step in improving the detector's performance is to increase our knowledge of the biological aerosol background in potential operational environments. Subway stations are enclosed public environments, which may be regarded as potential targets for incidents involving biological threat agents. In this study, the airborne bacterial community at a subway station in Norway was characterized (concentration level, diversity, and virulence- and survival-associated properties). In addition, a SASS 3100 high-volume air sampler and a matrix-assisted laser desorption ionization-time of flight mass spectrometry-based isolate screening procedure was used for these studies. The daytime level of airborne bacteria at the station was higher than the nighttime and outdoor levels, and the relative bacterial spore number was higher in outdoor air than at the station. The bacterial content, particle concentration, and size distribution were stable within each environment throughout the study (May to September 2010). The majority of the airborne bacteria belonged to the genera Bacillus, Micrococcus, and Staphylococcus, but a total of 37 different genera were identified in the air. These results suggest that anthropogenic sources are major contributors to airborne bacteria at subway stations and that such airborne communities could harbor virulence- and survival-associated properties of potential relevance for biological detection and surveillance, as well as for public health. Our findings also contribute to the development of realistic testing and evaluation schemes for biological detection/surveillance systems by providing information that can be used to mimic real-life operational airborne environments in controlled aerosol test chambers.

Characterization of Airborne Bacteria at an Underground Subway Station

Science.gov (United States)

Dybwad, Marius; Granum, Per Einar; Bruheim, Per

2012-01-01

The reliable detection of airborne biological threat agents depends on several factors, including the performance criteria of the detector and its operational environment. One step in improving the detector's performance is to increase our knowledge of the biological aerosol background in potential operational environments. Subway stations are enclosed public environments, which may be regarded as potential targets for incidents involving biological threat agents. In this study, the airborne bacterial community at a subway station in Norway was characterized (concentration level, diversity, and virulence- and survival-associated properties). In addition, a SASS 3100 high-volume air sampler and a matrix-assisted laser desorption ionization–time of flight mass spectrometry-based isolate screening procedure was used for these studies. The daytime level of airborne bacteria at the station was higher than the nighttime and outdoor levels, and the relative bacterial spore number was higher in outdoor air than at the station. The bacterial content, particle concentration, and size distribution were stable within each environment throughout the study (May to September 2010). The majority of the airborne bacteria belonged to the genera Bacillus, Micrococcus, and Staphylococcus, but a total of 37 different genera were identified in the air. These results suggest that anthropogenic sources are major contributors to airborne bacteria at subway stations and that such airborne communities could harbor virulence- and survival-associated properties of potential relevance for biological detection and surveillance, as well as for public health. Our findings also contribute to the development of realistic testing and evaluation schemes for biological detection/surveillance systems by providing information that can be used to mimic real-life operational airborne environments in controlled aerosol test chambers. PMID:22247150

Current strategies for improving food bacteria

NARCIS (Netherlands)

Kuipers, O P; Buist, Girbe; Kok, Jan

2000-01-01

Novel concepts and methodologies are emerging that hold great promise for the directed improvement of food-related bacteria, specifically lactic acid bacteria. Also, the battle against food spoilage and pathogenic bacteria can now be fought more effectively. Here we describe recent advances in

Molecular Level Design Principle behind Optimal Sizes of Photosynthetic LH2 Complex: Taming Disorder through Cooperation of Hydrogen Bonding and Quantum Delocalization.

Science.gov (United States)

Jang, Seogjoo; Rivera, Eva; Montemayor, Daniel

2015-03-19

The light harvesting 2 (LH2) antenna complex from purple photosynthetic bacteria is an efficient natural excitation energy carrier with well-known symmetric structure, but the molecular level design principle governing its structure-function relationship is unknown. Our all-atomistic simulations of nonnatural analogues of LH2 as well as those of a natural LH2 suggest that nonnatural sizes of LH2-like complexes could be built. However, stable and consistent hydrogen bonding (HB) between bacteriochlorophyll and the protein is shown to be possible only near naturally occurring sizes, leading to significantly smaller disorder than for nonnatural ones. Extensive quantum calculations of intercomplex exciton transfer dynamics, sampled for a large set of disorder, reveal that taming the negative effect of disorder through a reliable HB as well as quantum delocalization of the exciton is a critical mechanism that makes LH2 highly functional, which also explains why the natural sizes of LH2 are indeed optimal.

[Unique properties of highly radioresistant bacteria].

Science.gov (United States)

Romanovskaia, V A; Rokitko, P V; Malashenko, Iu R

2000-01-01

In connection with the Chernobyl Nuclear Power Plant (ChNPP) accident and the negative ecological after-effects for biota in this zone the interest has arisen to radioresistant bacteria, as to the most dynamic model of the given ecosystem, and to mechanisms which provide resistance of bacteria to ionizing radiation. The analysis of published data has shown that the radioresistant bacteria are not interrelated taxonomically and phylogenetically. The extreme radioresistant bacteria are represented by the Deinococcus species, which form a group phylogenetically close to the line Thermus-Meiothermus. Other radioresistant bacteria are the representatives of the genera Rubrobacter, Methylobacterium, Kocuria, Bacillus and some archebacteria. Data on natural habitats, of radioresistant bacteria are not numerous. In a number of cases it is difficult to distinguish their natural habitats, as they were isolated from the samples which were previously exposed to X-ray or gamma-irradiation, or from the ecosystems with the naturally raised radioactivity. To understand the strategy of survival of radioresistant bacteria, we briefly reviewed the mechanism of action of various species of radiation on cells and macromolecules; physiological signs of the cell damage caused by radiation; mechanisms eliminating (repairing) these damages. More details on mechanisms of the DNA repair in D. radiodurans are described. The extreme resistance of D. radiodurans to the DNA damaging factors is defined by 1) repair mechanisms which fundamentally differ from those in other procaryotes; 2) ability to increase the efficiency of a standard set of the DNA repairing proteins. Literary and own data on the effect of radiation on survival of various groups of bacteria in natural ecosystems are summarized. The ecological consequences of the ChNPP accident for soil bacteria in this region were estimated. The reduction of the number of soil bacteria and recession of microbial diversity under the effect of

Design of a store for encapsulated intermediate level radioactive waste

International Nuclear Information System (INIS)

Lloyd, A.I.; Robinson, G.; Price, M.S.T.

1989-01-01

The design of a new store for cemented intermediate level radioactive waste produced in unshielded 500 litre drums from the Winfrith Radwaste Treatment Plant is described. The store design has had to take account of local site constraints and disposal uncertainties. As a result, an innovative above ground storage tube design using interlocking, commercially available, concrete pipe rings has been selected. Other special features are that the store is easily capable of being extended whilst in service and is simple and cheap to decommission. A quality assessment facility for the drummed waste is an integral part of the store complex. (author)

Antibacterial Surface Design of Titanium-Based Biomaterials for Enhanced Bacteria-Killing and Cell-Assisting Functions Against Periprosthetic Joint Infection.

Science.gov (United States)

Wang, Jiaxing; Li, Jinhua; Qian, Shi; Guo, Geyong; Wang, Qiaojie; Tang, Jin; Shen, Hao; Liu, Xuanyong; Zhang, Xianlong; Chu, Paul K

2016-05-04

Periprosthetic joint infection (PJI) is one of the formidable and recalcitrant complications after orthopedic surgery, and inhibiting biofilm formation on the implant surface is considered crucial to prophylaxis of PJI. However, it has recently been demonstrated that free-floating biofilm-like aggregates in the local body fluid and bacterial colonization on the implant and peri-implant tissues can coexist and are involved in the pathogenesis of PJI. An effective surface with both contact-killing and release-killing antimicrobial capabilities can potentially abate these concerns and minimize PJI caused by adherent/planktonic bacteria. Herein, Ag nanoparticles (NPs) are embedded in titania (TiO2) nanotubes by anodic oxidation and plasma immersion ion implantation (PIII) to form a contact-killing surface. Vancomycin is then incorporated into the nanotubes by vacuum extraction and lyophilization to produce the release-killing effect. A novel clinical PJI model system involving both in vitro and in vivo use of methicillin-resistant Staphylococcus aureus (MRSA) ST239 is established to systematically evaluate the antibacterial properties of the hybrid surface against planktonic and sessile bacteria. The vancomycin-loaded and Ag-implanted TiO2 nanotubular surface exhibits excellent antimicrobial and antibiofilm effects against planktonic/adherent bacteria without appreciable silver ion release. The fibroblasts/bacteria cocultures reveal that the surface can help fibroblasts to combat bacteria. We first utilize the nanoarchitecture of implant surface as a bridge between the inorganic bactericide (Ag NPs) and organic antibacterial agent (vancomycin) to achieve total victory in the battle of PJI. The combination of contact-killing and release-killing together with cell-assisting function also provides a novel and effective strategy to mitigate bacterial infection and biofilm formation on biomaterials and has large potential in orthopedic applications.

Single bacteria movement tracking by online microscopy--a proof of concept study.

Directory of Open Access Journals (Sweden)

Andreas Ziegler

Full Text Available In this technical report we demonstrate a low-cost online unit allowing movement tracking of flagellated bacteria on a single-cell level during fermentation processes. The system's ability to distinguish different metabolic states (viability of bacteria by movement velocity was investigated. A flow-through cuvette with automatically adjustable layer thickness was developed. The cuvette can be used with most commercially available laboratory microscopes equipped with 40× amplification and a digital camera. In addition, an automated sample preparation unit and a software module was developed measuring size, moved distance, and speed of bacteria. In a proof of principle study the movement velocities of Bacillus amyloliquefaciens FZB42 during three batch fermentation processes were investigated. In this process the bacteria went through different metabolic states, vegetative growth, diauxic shift, vegetative growth after diauxic shift, and sporulation. It was shown that the movement velocities during the different metabolic states significantly differ from each other. Therefore, the described setup has the potential to be used as a bacteria viability monitoring tool. In contrast to some other techniques, such as electro-optical techniques, this method can even be used in turbid production media.

Impact of nanoscale topography on genomics and proteomics of adherent bacteria.

Science.gov (United States)

Rizzello, Loris; Sorce, Barbara; Sabella, Stefania; Vecchio, Giuseppe; Galeone, Antonio; Brunetti, Virgilio; Cingolani, Roberto; Pompa, Pier Paolo

2011-03-22

Bacterial adhesion onto inorganic/nanoengineered surfaces is a key issue in biotechnology and medicine, because it is one of the first necessary steps to determine a general pathogenic event. Understanding the molecular mechanisms of bacteria-surface interaction represents a milestone for planning a new generation of devices with unanimously certified antibacterial characteristics. Here, we show how highly controlled nanostructured substrates impact the bacterial behavior in terms of morphological, genomic, and proteomic response. We observed by atomic force microscopy (AFM) and scanning electron microscopy (SEM) that type-1 fimbriae typically disappear in Escherichia coli adherent onto nanostructured substrates, as opposed to bacteria onto reference glass or flat gold surfaces. A genetic variation of the fimbrial operon regulation was consistently identified by real time qPCR in bacteria interacting with the nanorough substrates. To gain a deeper insight into the molecular basis of the interaction mechanisms, we explored the entire proteomic profile of E. coli by 2D-DIGE, finding significant changes in the bacteria adherent onto the nanorough substrates, such as regulations of proteins involved in stress processes and defense mechanisms. We thus demonstrated that a pure physical stimulus, that is, a nanoscale variation of surface topography, may play per se a significant role in determining the morphological, genetic, and proteomic profile of bacteria. These data suggest that in depth investigations of the molecular processes of microorganisms adhering to surfaces are of great importance for the design of innovative biomaterials with active biological functionalities.

Cholesterol Assimilation by Lactobacillus Probiotic Bacteria: An In Vitro Investigation

OpenAIRE

Tomaro-Duchesneau, Catherine; Jones, Mitchell L.; Shah, Divya; Jain, Poonam; Saha, Shyamali; Prakash, Satya

2014-01-01

Excess cholesterol is associated with cardiovascular diseases (CVD), an important cause of mortality worldwide. Current CVD therapeutic measures, lifestyle and dietary interventions, and pharmaceutical agents for regulating cholesterol levels are inadequate. Probiotic bacteria have demonstrated potential to lower cholesterol levels by different mechanisms, including bile salt hydrolase activity, production of compounds that inhibit enzymes such as 3-hydroxy-3-methylglutaryl coenzyme A, and ch...

NASA System-Level Design, Analysis and Simulation Tools Research on NextGen

Science.gov (United States)

Bardina, Jorge

2011-01-01

A review of the research accomplished in 2009 in the System-Level Design, Analysis and Simulation Tools (SLDAST) of the NASA's Airspace Systems Program is presented. This research thrust focuses on the integrated system-level assessment of component level innovations, concepts and technologies of the Next Generation Air Traffic System (NextGen) under research in the ASP program to enable the development of revolutionary improvements and modernization of the National Airspace System. The review includes the accomplishments on baseline research and the advancements on design studies and system-level assessment, including the cluster analysis as an annualization standard of the air traffic in the U.S. National Airspace, and the ACES-Air MIDAS integration for human-in-the-loop analyzes within the NAS air traffic simulation.

Bactericide for sulfate-reducing bacteria

Energy Technology Data Exchange (ETDEWEB)

Shklyar, T F; Anoshina, G M; Blokhin, V Ye; Kisarrev, Ye L; Novikovsa, G M

1981-01-01

The aim of the invention is to find a bactericide for sulfate-reducing bacteria of oil fields in Western Siberia in order to suppress the biocorrosive activity on oil industry equipment. This goal is achieved by using M-nitroacetanylide as the bactericide of sulfate-reducing bacteria. This agent suppresses the activity of a stored culture of sulfate-reducing bacteria that comes from industrial waste waters injection wells of the Smotlor oil field.

Design junctions

DEFF Research Database (Denmark)

Jørgensen, Ulrik

2012-01-01

. This case study illustrates how dominant regimes of practice, established through the conception of pathogen bacteria and antibacterial treatments and disinfection, are now creating signals that call into question fundamental design of hygiene practices. By examining the epistemic assumptions of scientific...

High-level radioactive waste glass and storage canister design

International Nuclear Information System (INIS)

Slate, S.C.; Ross, W.A.

1979-01-01

Management of high-level radioactive wastes is a primary concern in nuclear operations today. The main objective in managing these wastes is to convert them into a solid, durable form which is then isolated from man. A description is given of the design and evaluation of this waste form. The waste form has two main components: the solidified waste and the storage canister. The solid waste form discussed in this study is glass. Waste glasses have been designed to be inert to water attack, physically rugged, low in volatility, and stable over time. Two glass-making processes are under development at PNL. The storage canister is being designed to provide high-integrity containment for solidified wastes from processing to terminal storage. An outline is given of the steps in canister design: material selection, stress and thermal analyses, quality verification, and postfill processing. Examples are given of results obtained from actual nonradioactive demonstration tests. 14 refs

How Fitness Reduced, Antimicrobial Resistant Bacteria Survive and Spread

DEFF Research Database (Denmark)

Græsbøll, Kaare; Nielsen, Søren Saxmose; Toft, Nils

2014-01-01

More than 30% of E. coli strains sampled from pig farms in Denmark over the last five years were resistant to the commonly used antimicrobial tetracycline. This raises a number of questions: How is this high level sustained if resistant bacteria have reduced growth rates? Given that there are mul...

Low-level burial grounds dangerous waste permit application design documents

International Nuclear Information System (INIS)

1990-08-01

This document serves a supplement to the already existing ''Low-Level Burial Ground Dangerous Waste Permit Application Design Documents.'' This paper contains information regarding drawings, construction specifications, and liner/leachate compatibility test plans

Mycorrhiza helper bacteria

Energy Technology Data Exchange (ETDEWEB)

Deveau, Aurelie [French National Insitute for Agricultural Research (INRA); Labbe, Jessy [ORNL

2016-10-01

This chapter focuses on the Mycorrhiza Helper Bacteria (MHB), a generic name given to bacteria which stimulate the formation of mycorrhizal symbiosis. By extension, some bacterial strains that positively impact the functioning of mycorrhizal symbiosis are also called MHB. These bacteria have applicative interests, as they indirectly improve the health and growth of tree seedlings. MHB are not restricted to a specific type of ecosystem, but are rather generalist in the way that they associate with both herbaceous and woody mycorrhizal plants from boreal, temperate, arid and tropical ecosystems. However, understanding the molecular mechanisms and their specificities will help us to know more about the ecology of the MHB. The process of acquisition varies between fungal species; while ectomycorrhizal fungi most probably recurrently acquire them from the environment, the association between bacterial endosymbionts and Glomeromycota probably dates back to very ancient times, and has since been vertically transmitted.

Fecal bacteria from treatment-naive Crohn's disease patients can skew helper T cell responses.

Science.gov (United States)

Ma, Fei; Zhang, Yi; Xing, Junjie; Song, Xiaoling; Huang, Ling; Weng, Hao; Wu, Xiangsong; Walker, Emma; Wang, Zhongchuan

2017-12-01

Many studies have demonstrated that the inflamed mucosa of Crohn's disease (CD) patients presented a disturbed gut commensal community, and the shift in microbial composition and species variety is associated with disease severity. To establish a link between changes in the intestinal bacterial composition and the alteration of inflammation, we obtained fecal bacteria from CD patients and non-CD controls. The bacteria were then used to stimulate the peripheral blood mononuclear cells (PBMCs) from one non-CD individual. We found that the frequency of IFN-γ- and IL-17-expressing CD4 T cells was significantly higher after stimulation with CD bacteria than with non-CD bacteria, while the frequency of IL-4- and IL-10-expressing CD4 T cells was significantly decreased after stimulation with CD bacteria. A similar trend was observed in the level of cytokine expression and transcription expression. However, this difference was not clear-cut, as overlapping regions were observed between the two groups. With longer stimulation using CD bacteria, the skewing toward Th1/Th17 responses were further increased. This increase depended on the presence of monocytes/macrophages. Interestingly, we also found that B cells presented an inhibitory effect in CD bacteria-mediated skewing toward Th1/Th17 cells and promoted IL-10 secretion in CD bacteria-stimulated PBMCs. Together, our results demonstrated that CD bacteria could promote Th1/Th17 inflammation in a host factor-independent fashion. Copyright © 2017 Elsevier Inc. All rights reserved.

Web-Based Museum Trails on PDAs for University-Level Design Students: Design and Evaluation

Science.gov (United States)

Reynolds, R.; Walker, K.; Speight, C.

2010-01-01

This paper describes the development and evaluation of web-based museum trails for university-level design students to access on handheld devices in the Victoria and Albert Museum (V&A) in London. The trails offered students a range of ways of exploring the museum environment and collections, some encouraging students to interpret objects and…

Significance of high level test data in piping design

International Nuclear Information System (INIS)

McLean, J.L.; Bitner, J.L.

1991-01-01

During the 1980's the piping technical community in the U.S. initiated a series of research activities aimed at reducing the conservatism inherent in nuclear piping design. One of these activities was directed at the application of the ASME Code rules to the design of piping subjected to dynamic loads. This paper surveys the test data obtained from three groups in the U.S. and none in the U.K., and correlates the findings as they relate to the failure modes of piping subjected to seismic loads. The failure modes experienced as the result of testing at dynamic loads significantly in excess of anticipated loads specified for any of the ASME Code service levels are discussed. A recommendation is presented for modifying the Code piping rules to reduce the conservatism inherent in seismic design

Evaluation of VITEK mass spectrometry (MS), a matrix-assisted laser desorption ionization time-of-flight MS system for identification of anaerobic bacteria.

Science.gov (United States)

Lee, Wonmok; Kim, Myungsook; Yong, Dongeun; Jeong, Seok Hoon; Lee, Kyungwon; Chong, Yunsop

2015-01-01

By conventional methods, the identification of anaerobic bacteria is more time consuming and requires more expertise than the identification of aerobic bacteria. Although the matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) systems are relatively less studied, they have been reported to be a promising method for the identification of anaerobes. We evaluated the performance of the VITEK MS in vitro diagnostic (IVD; 1.1 database; bioMérieux, France) in the identification of anaerobes. We used 274 anaerobic bacteria isolated from various clinical specimens. The results for the identification of the bacteria by VITEK MS were compared to those obtained by phenotypic methods and 16S rRNA gene sequencing. Among the 249 isolates included in the IVD database, the VITEK MS correctly identified 209 (83.9%) isolates to the species level and an additional 18 (7.2%) at the genus level. In particular, the VITEK MS correctly identified clinically relevant and frequently isolated anaerobic bacteria to the species level. The remaining 22 isolates (8.8%) were either not identified or misidentified. The VITEK MS could not identify the 25 isolates absent from the IVD database to the species level. The VITEK MS showed reliable identifications for clinically relevant anaerobic bacteria.

New molecular method to detect denitrifying anaerobic methane oxidation bacteria from different environmental niches.

Science.gov (United States)

Xu, Sai; Lu, Wenjing; Muhammad, Farooq Mustafa; Liu, Yanting; Guo, Hanwen; Meng, Ruihong; Wang, Hongtao

2018-03-01

The denitrifying anaerobic methane oxidation is an ecologically important process for reducing the potential methane emission into the atmosphere. The responsible bacterium for this process was Candidatus Methylomirabilis oxyfera belonging to the bacterial phylum of NC10. In this study, a new pair of primers targeting all the five groups of NC10 bacteria was designed to amplify NC10 bacteria from different environmental niches. The results showed that the group A was the dominant NC10 phylum bacteria from the sludges and food waste digestate while in paddy soil samples, group A and group B had nearly the same proportion. Our results also indicated that NC10 bacteria could exist in a high pH environment (pH9.24) from the food waste treatment facility. The Pearson relationship analysis showed that the pH had a significant positive relationship with the NC10 bacterial diversity (pbacteria. Copyright © 2017. Published by Elsevier B.V.

Intermediate-level disinfection with accelerated hydrogen peroxide prevents accumulation of bacteria in Versajet™ tubing during repeated daily debridement using simulated-use testing with an inoculated pork hock.

Science.gov (United States)

Gawaziuk, J P; Alfa, M J; Olson, N; Logsetty, S

2014-05-01

This study assesses the feasibility of using the Versajet™ system (VJS) on an inoculated pork hock (PH) skin surface sequentially for 8 days with daily cleaning and intermediate-level disinfection (ILD). Daily, PHs were inoculated with bacteria suspended in artificial test soil (ATS). An ILD protocol with accelerated hydrogen peroxide (AHP, OxivirTB(®)) was employed to clean and disinfect the VJS between debridements. PH skin contains 6.1-6.8×10(6)cfu/cm(2) bacteria. Bacterial counts in the handpiece and discharge hoses immediately after debridement of the PHs, and before cleaning, increased throughout the study period (5.19-6.43log10cfu/mL). Cleaning with the ILD protocol was reduced bacterial counts on the VJS by 6-log. Protein, a surrogate marker of organic contamination, was also reduced post-cleaning and ILD. Compared to a maximum post-debridement level of protein (57.9 μg/mL) obtained before ILD, VJS protein levels dropped to 9.8 (handpiece) and 13.8 μg/mL (discharge hose). Disinfection of the handpiece and discharge hose after debridement with AHP resulted in a 6-log reduction in bacterial count and 4.2 fold reduction in protein. An ILD protocol with an AHP may be a feasible method for serial skin surface debridements with the VJS for up to eight days. Copyright © 2013 Elsevier Ltd and ISBI. All rights reserved.

Market Designs for High Levels of Variable Generation: Preprint

Energy Technology Data Exchange (ETDEWEB)

Milligan, M.; Holttinen, H.; Kiviluoma, J.; Orths, A.; Lynch, M.; Soder, L.

2014-10-01

Variable renewable generation is increasing in penetration in modern power systems, leading to higher variability in the supply and price of electricity as well as lower average spot prices. This raises new challenges, particularly in ensuring sufficient capacity and flexibility from conventional technologies. Because the fixed costs and lifetimes of electricity generation investments are significant, designing markets and regulations that ensure the efficient integration of renewable generation is a significant challenge. This papers reviews the state of play of market designs for high levels of variable generation in the United States and Europe and considers new developments in both regions.

Lactic Acid Bacteria from Kefir Increase Cytotoxicity of Natural Killer Cells to Tumor Cells

Directory of Open Access Journals (Sweden)

Takuya Yamane

2018-03-01

Full Text Available The Japanese fermented beverage, homemade kefir, contains six lactic acid bacteria: Lactococcus. lactis subsp. Lactis, Lactococcus. lactis subsp. Cremoris, Lactococcus. Lactis subsp. Lactis biovar diacetylactis, Lactobacillus plantarum, Leuconostoc meseuteroides subsp. Cremoris and Lactobacillus casei. In this study, we found that a mixture of the six lactic acid bacteria from kefir increased the cytotoxicity of human natural killer KHYG-1 cells to human chronic myelogenous leukemia K562 cells and colorectal tumor HCT116 cells. Furthermore, levels of mRNA expression and secretion of IFN-γ (interferon gamma increased in KHYG-1 cells that had been treated with the six lactic acid bacteria mixture from kefir. The results suggest that the six lactic acid bacteria mixture from kefir has strong effects on natural immunity and tumor cell cytotoxicity.

Lactic acid bacteria affect serum cholesterol levels, harmful fecal enzyme activity, and fecal water content

OpenAIRE

Chung Myung; Shin Hea; Lee Kyung; Kim Mi; Baek Eun; Jang Seok; Lee Do; Kim Jin; Lee Kang; Ha Nam

2009-01-01

Abstract Background Lactic acid bacteria (LAB) are beneficial probiotic organisms that contribute to improved nutrition, microbial balance, and immuno-enhancement of the intestinal tract, as well as lower cholesterol. Although present in many foods, most trials have been in spreads or dairy products. Here we tested whether Bifidobacteria isolates could lower cholesterol, inhibit harmful enzyme activities, and control fecal water content. Methods In vitro culture experiments were performed to ...

Contamination of water wells in Khoms city with pathogenic coliform bacteria

International Nuclear Information System (INIS)

Mahjoub, Tariq M.; Buazzi, Mahmoud M.; Jamil, Ahmad Y.

2007-01-01

240 Samples from 60 water wells in and around the area of city of Khoms city (in northwestern Libya) were analyzed over four successive seasons for count of faecal Coliform bacteria, of which antibiotic resistance was later assessed. Standard methods were used for analysis of faecla coliform bacteria. Water wells contained varying levels of faecal coliform bacteria ranging from a Most Probable Number of 0 to 1.8 x 10 3 cfu/100 ml, with zero isolates at autumn and winter seasons, while wells dug at private farms had the highest percentage of contamination, reaching 56.6% of wells in autumn, and also had the highest number of faecal coliform isolates, 1,8x10 3 cfu/100 ml, in spring and summer seasons, strains of isolated Escherichia coli were most sensitive to chloramphenicol, and most resistant to tetracycline. (author)

Lactic Acid Bacteria and Bifidobacteria with Potential to Design Natural Biofunctional Health-Promoting Dairy Foods.

Science.gov (United States)

Linares, Daniel M; Gómez, Carolina; Renes, Erica; Fresno, José M; Tornadijo, María E; Ross, R P; Stanton, Catherine

2017-01-01

Consumer interest in healthy lifestyle and health-promoting natural products is a major driving force for the increasing global demand of biofunctional dairy foods. A number of commercial sources sell synthetic formulations of bioactive substances for use as dietary supplements. However, the bioactive-enrichment of health-oriented foods by naturally occurring microorganisms during dairy fermentation is in increased demand. While participating in milk fermentation, lactic acid bacteria can be exploited in situ as microbial sources for naturally enriching dairy products with a broad range of bioactive components that may cover different health aspects. Several of these bioactive metabolites are industrially and economically important, as they are claimed to exert diverse health-promoting activities on the consumer, such as anti-hypertensive, anti-inflammatory, and anti-diabetic, anti-oxidative, immune-modulatory, anti-cholesterolemic, or microbiome modulation. This review aims at discussing the potential of these health-supporting bacteria as starter or adjunct cultures for the elaboration of dairy foods with a broad spectrum of new functional properties and added value.

Lactic Acid Bacteria and Bifidobacteria with Potential to Design Natural Biofunctional Health-Promoting Dairy Foods

Directory of Open Access Journals (Sweden)

Daniel M. Linares

2017-05-01

Full Text Available Consumer interest in healthy lifestyle and health-promoting natural products is a major driving force for the increasing global demand of biofunctional dairy foods. A number of commercial sources sell synthetic formulations of bioactive substances for use as dietary supplements. However, the bioactive-enrichment of health-oriented foods by naturally occurring microorganisms during dairy fermentation is in increased demand. While participating in milk fermentation, lactic acid bacteria can be exploited in situ as microbial sources for naturally enriching dairy products with a broad range of bioactive components that may cover different health aspects. Several of these bioactive metabolites are industrially and economically important, as they are claimed to exert diverse health-promoting activities on the consumer, such as anti-hypertensive, anti-inflammatory, and anti-diabetic, anti-oxidative, immune-modulatory, anti-cholesterolemic, or microbiome modulation. This review aims at discussing the potential of these health-supporting bacteria as starter or adjunct cultures for the elaboration of dairy foods with a broad spectrum of new functional properties and added value.

COMPARISON THE NUMBER OF BACTERIA BETWEEN WASHING HANDS USING SOAP AND HAND SANITIZER AS A BACTERIOLOGY LEARNING RESOURCE FOR STUDENTS

OpenAIRE

Satya Darmayani; Askrening Askrening; Apita Ariyani

2017-01-01

Hands are the principal carriers of bacterial diseases, therefore very important to know that washing hands with soap or hand sanitizer is highly effective healthy behaviors to reduce bacteria in the palm. This study aimed to determine the total number of bacteria between washing hands with soap and hand sanitizer, also applying the results of these studies as a learning resource in bacteriology. The research design was the true experiment with pretest-posttest control group research design a...

Statistical optimization of gold recovery from difficult leachable sulphide minerals using bacteria

Energy Technology Data Exchange (ETDEWEB)

Ahmed, Hussin A.M. [King Abdulaziz Univ., Jeddah (Saudi Arabia). Mining Engineering Dept.; El-Midany, Ayman A. [King Saud Univ., Riyadh (Saudi Arabia)

2012-07-01

Some of refractory gold ores represent one of the difficult processable ores due to fine dissemination and interlocking of the gold grains with the associated sulphide minerals. This makes it impossible to recover precious metals from sulphide matrices by direct cyanide leaching even at high consumption of cyanide solution. Research to solve this problem is numerous. Application of bacteria shows that, some types of bacteria have great affect on sulphides bio-oxidation and consequently facilitate the leaching process. In this paper, leaching of Saudi gold ore, from Alhura area, containing sulphides before cyanidation is studied to recover gold from such ores applying bacteria. The process is investigated using stirred reactor bio-leaching rather than heap bio-leaching. Using statistical analysis the main affecting variables under studied conditions were identified. The design results indicated that the dose of bacteria, retention time and nutrition K{sub 2}SO{sub 4} are the most significant parameters. The higher the bacterial dose and the bacterial nutrition, the better is the concentrate grade. Results show that the method is technically effective in gold recovery. A gold concentrate containing > 100 g/t gold was obtained at optimum conditions, from an ore containing < 2 g/t gold i.e., 10 ml bacterial dose, 6 days retention time, and 6.5 kg/t K{sub 2}SO{sub 4}as bacteria nutrition. (orig.)

Effect of soil salinity and nutrient levels on the community structure of the root-associated bacteria of the facultative halophyte, Tamarix ramosissima, in southwestern United States.

Science.gov (United States)

Taniguchi, Takeshi; Imada, Shogo; Acharya, Kumud; Iwanaga, Fumiko; Yamanaka, Norikazu

2015-01-01

Tamarix ramosissima is a tree species that is highly resistant to salt and drought. The Tamarix species survives in a broad range of environmental salt levels, and invades major river systems in southwestern United States. It may affect root-associated bacteria (RB) by increasing soil salts and nutrients. The effects of RB on host plants may vary even under saline conditions, and the relationship may be important for T. ramosissima. However, to the best of our knowledge, there have been no reports relating to T. ramosissima RB and its association with salinity and nutrient levels. In this study, we have examined this association and the effect of arbuscular mycorrhizal colonization of T. ramosissima on RB because a previous study has reported that colonization of arbuscular mycorrhizal fungi affected the rhizobacterial community (Marschner et al., 2001). T. ramosissima roots were collected from five locations with varying soil salinity and nutrient levels. RB community structures were examined by terminal restriction fragment (T-RF) length polymorphism, cloning, and sequencing analyses. The results suggest that RB richness, or the diversity of T. ramosissima, have significant negative relationships with electrical conductivity (EC), sodium concentration (Na), and the colonization of arbuscular mycorrhizal fungi, but have a significant positive relationship with phosphorus in the soil. However, at each T-RF level, positive correlations between the emergence of some T-RFs and EC or Na were observed. These results indicate that high salinity decreased the total number of RB species, but some saline-tolerant RB species multiplied with increasing salinity levels. The ordination scores of nonmetric multidimensional scale analysis of RB community composition show significant relationships with water content, calcium concentration, available phosphorus, and total nitrogen. These results indicate that the RB diversity and community composition of T. ramosissima are affected

Effect of nematodes on rhizosphere colonization by seed-applied bacteria.

Science.gov (United States)

Knox, Oliver G G; Killham, Ken; Artz, Rebekka R E; Mullins, Chris; Wilson, Michael

2004-08-01

There is much interest in the use of seed-applied bacteria for biocontrol and biofertilization, and several commercial products are available. However, many attempts to use this strategy fail because the seed-applied bacteria do not colonize the rhizosphere. Mechanisms of rhizosphere colonization may involve active bacterial movement or passive transport by percolating water or plant roots. Transport by other soil biota is likely to occur, but this area has not been well studied. We hypothesized that interactions with soil nematodes may enhance colonization. To test this hypothesis, a series of microcosm experiments was carried out using two contrasting soils maintained under well-defined physical conditions where transport by mass water flow could not occur. Seed-applied Pseudomonas fluorescens SBW25 was capable of rhizosphere colonization at matric potentials of -10 and -40 kPa in soil without nematodes, but colonization levels were substantially increased by the presence of nematodes. Our results suggest that nematodes can have an important role in rhizosphere colonization by bacteria in soil.

Multiple sample flow through immunomagnetic separator for concentrating pathogenic bacteria

International Nuclear Information System (INIS)

Rotariu, Ovidiu; Ogden, Iain D; MacRae, Marion; Udrea, Laura Elena; Strachan, Norval J C

2005-01-01

The standard method of immunomagnetic separation for isolating pathogenic bacteria from food and environmental matrices processes 1 ml volumes. Pathogens present at low levels ( 97% recovery of polydisperse magnetic particles (diameter range 1 to 8 μm) containing 29-33% w/w Fe 3 O 4 content. Between 70 and 130 times more of the pathogenic bacteria Escherichia coli O157 is recovered from PBS compared with the standard 1 ml method. Also, the recovery of E. coli O157 from beef mince homogenates, after a 4 h incubation at 42 deg. C, is between 80 and 180 times higher than the standard 1 ml method

Quantitative assay for the colonization ability of heterogeneous bacteria on controlled nanopillar structures

International Nuclear Information System (INIS)

Jin, Lin; Guo, Wen; Zhang, Yali; Xue, Peihong; Gao, Hainan; Zhao, Ming; Zheng, Chen; Han, Dong

2015-01-01

The colonization ability of bacteria on biomaterial surfaces is influenced by the morphology of the bacteria and the nanotopography of the biomaterial. However, interactions between the bacterial morphology and nanotopography of biomaterials have not yet been completely elucidated. In this article, we quantitatively characterized the bacterial morphology to illuminate the integrated effects of polyethylene terephthalate (PET) nanopillar arrays on the colonization of bacteria cells with different shapes. Our results demonstrated that the interaction between interpillar spacing and the diameter of the bacterial cells impacted the number of bacterial cells that adhered to different PET substrates. The interpillar spacing of nanopillar arrays promotes bacterial adhesion in a definite range (<50 nm). However, further increasing the interpillar spacing inhibited the adhesion of bacteria to the nanopillar arrays. Moreover, the interpillar spacing also influenced the morphologies of adherent bacterial cells on the PET nanopillar arrays, which consequently facilitated bacterial adhesion to the nanopillar arrays. Our findings enhance the understanding of interactions between controlled nanotopography and bacterial colonization and provide an appropriate parameter for the design of antibacterial materials with nanotopography. (paper)

Transcriptional analysis of disk abalone (Haliotis discus discus) antioxidant enzymes against marine bacteria and virus challenge.

Science.gov (United States)

De Zoysa, Mahanama; Whang, Ilson; Nikapitiya, Chamilani; Oh, Chulhong; Choi, Cheol Young; Lee, Jehee

2011-07-01

Diverse antioxidant enzymes are essential for marine organisms to overcome oxidative stress as well as for the fine-tuning of immune reactions through activating different signal transduction pathways. This study describes the transcriptional analysis of antioxidant enzymes of disk abalone by challenging with bacteria (Vibrio alginolyticus, Vibrio parahemolyticus, and Listeria monocytogenes) and viral hemorrhagic septicemia virus (VHSV). Upon bacteria and VHSV challenge, Manganese superoxide dismutase (MnSOD), Copper, Zinc superoxide dismutase (CuZnSOD), catalase, thioredoxin peroxidase (TPx), Selenium-dependent glutathione peroxidase (SeGPx), and thioredoxin-2 (TRx-2) expression levels were altered in gills, and hemocytes at different magnitudes. In gills, only MnSOD, catalase, and SeGPx genes were completely upregulated by post-challenge of bacterial and VHSV. Among them, SeGPx demonstrated strong upregulation by 16-fold (bacteria) and 2-fold (VHSV) in gills, and 5-fold (bacteria) and 3.0-fold (VHSV) in hemocytes. None of the genes examined were downregulated (in gills and hemocytes) by bacteria challenge even though CuZnSOD and TPx showed downregulation (completely) in hemocytes by VHSV. In general, abalone hemocytes had lower potential to induce antioxidant enzyme transcripts upon bacteria and VHSV challenge than gills. Based upon these results, we suggest that abalones induce oxidative stress in tissues during the bacteria and VHSV challenge, and the identified response of antioxidant enzymes could be supported for maintaining a low-level of reactive oxygen species (ROS) that may serve as a signal for activating immune reactions against pathogenic conditions. Copyright © 2011 Elsevier Ltd. All rights reserved.

Horizontal gene transfer between bacteria.

Science.gov (United States)

Heuer, Holger; Smalla, Kornelia

2007-01-01

Horizontal gene transfer (HGT) refers to the acquisition of foreign genes by organisms. The occurrence of HGT among bacteria in the environment is assumed to have implications in the risk assessment of genetically modified bacteria which are released into the environment. First, introduced genetic sequences from a genetically modified bacterium could be transferred to indigenous micro-organisms and alter their genome and subsequently their ecological niche. Second, the genetically modified bacterium released into the environment might capture mobile genetic elements (MGE) from indigenous micro-organisms which could extend its ecological potential. Thus, for a risk assessment it is important to understand the extent of HGT and genome plasticity of bacteria in the environment. This review summarizes the present state of knowledge on HGT between bacteria as a crucial mechanism contributing to bacterial adaptability and diversity. In view of the use of GM crops and microbes in agricultural settings, in this mini-review we focus particularly on the presence and role of MGE in soil and plant-associated bacteria and the factors affecting gene transfer.

Efecto de la asociación alga-bacteria Bostrychia calliptera (Rhodomelaceae en el porcentaje de remoción de cromo en laboratorio The effect of chromium removal by Algae-bacteria Bostrychia calliptera (Rhodomelaceae consortia under laboratory conditions

Directory of Open Access Journals (Sweden)

Ana Lucía Rengifo-Gallego

2012-09-01

Full Text Available Para determinar el porcentaje de remoción de cromo en la asociación alga-bacteria, se tomaron ejemplares del alga Bostrychia calliptera de pneumatóforos de Avicennia germinans y Rizophora mangle, en la desembocadura del Río Dagua, Pacífico colombiano. El ensayo se realizó in vitro en agua marina sintética a dos concentraciones de cromo 5 y 10mg/L, empleando biorreactores con cuatro tratamientos; i material Alga-Bacteria (AB, ii material algal con antibiótico Alga-antibiótico (AA, iii consorcio bacteriano natural (CBN y iv control sin presencia de B. calliptera ni bacteria. Se monitoreó el comportamiento de poblaciones bacterianas y el porcentaje de disminución de cromo mediante AAS (Espectroscopía de absorción atómica. Se obtuvo diferencias significativas entre los tratamientos Alga-bacteria (AB y el consorcio bacteriano natural (CBN, siendo Alga-bacteria más eficiente a 10mg/L (87%. El consorcio bacteriano natural CBN obtuvo mayor porcentaje de remoción a bajas concentraciones de cromo a 5ppm (62.85%. Los resultados mostraron una interacción positiva entre las bacterias asociadas (CBN a la superficie del alga roja B. calliptera en su proceso acumulativo de cromo.Water pollution is one of the most important environmental problems worldwide. Recently, biotechnology studies have oriented efforts to study algae-bacterium consortia with the aim to understand the mechanisms to find a possible solution in environmental sciences. This study determined the percentage of chromium removal by the alga-bacterium association exposed to a set of different chromium concentrations under controlled in vitro conditions. Wild plants of Bostrychia calliptera associated with bacterial populations were collected from Dagua River, Pacific coast of Colombia, and were monitored in the laboratory. The trial was conducted with synthetic seawater in bioreactors at two chromium levels: 5 and 10mg/L, and four different experimental treatments: i algae-bacteria

Utility of 16S rDNA Sequencing for Identification of Rare Pathogenic Bacteria.

Science.gov (United States)

Loong, Shih Keng; Khor, Chee Sieng; Jafar, Faizatul Lela; AbuBakar, Sazaly

2016-11-01

Phenotypic identification systems are established methods for laboratory identification of bacteria causing human infections. Here, the utility of phenotypic identification systems was compared against 16S rDNA identification method on clinical isolates obtained during a 5-year study period, with special emphasis on isolates that gave unsatisfactory identification. One hundred and eighty-seven clinical bacteria isolates were tested with commercial phenotypic identification systems and 16S rDNA sequencing. Isolate identities determined using phenotypic identification systems and 16S rDNA sequencing were compared for similarity at genus and species level, with 16S rDNA sequencing as the reference method. Phenotypic identification systems identified ~46% (86/187) of the isolates with identity similar to that identified using 16S rDNA sequencing. Approximately 39% (73/187) and ~15% (28/187) of the isolates showed different genus identity and could not be identified using the phenotypic identification systems, respectively. Both methods succeeded in determining the species identities of 55 isolates; however, only ~69% (38/55) of the isolates matched at species level. 16S rDNA sequencing could not determine the species of ~20% (37/187) of the isolates. The 16S rDNA sequencing is a useful method over the phenotypic identification systems for the identification of rare and difficult to identify bacteria species. The 16S rDNA sequencing method, however, does have limitation for species-level identification of some bacteria highlighting the need for better bacterial pathogen identification tools. © 2016 Wiley Periodicals, Inc.

Presenting a Multi-level Superstructure Optimization Approach for Mechatronic System Design

DEFF Research Database (Denmark)

Pedersen, Henrik C.; Andersen, Torben Ole; Bech, Michael Møller

2010-01-01

Synergism and integration in the design process is what sets apart a Mechatronic System from a traditional, multidisciplinary system. However the typical design approach has been to divide the design problem into sub problems for each technology area (mechanics, electronics and control) and descr......Synergism and integration in the design process is what sets apart a Mechatronic System from a traditional, multidisciplinary system. However the typical design approach has been to divide the design problem into sub problems for each technology area (mechanics, electronics and control......) and describe the interface between the technologies, whereas the lack of well-established, systematic engineering methods to form the basic set-off in analysis and design of complete mechatronic systems has been obvious. The focus of the current paper is therefore to present an integrated design approach...... for mechatronic system design, utilizing a multi-level superstructure optimization based approach. Finally two design examples are presented and the possibilities and limitations of the approach are outlined....

Screening and characterization of phosphate solubilizing bacteria from isolate of thermophilic bacteria

Science.gov (United States)

Yulianti, Evy; Rakhmawati, Anna

2017-08-01

The aims of this study were to select bacteria that has the ability to dissolve phosphate from thermophilic bacteria isolates after the Merapi eruption. Five isolates of selected bacteria was characterized and continued with identification. Selection was done by using a pikovskaya selective medium. Bacterial isolates were grown in selective medium and incubated for 48 hours at temperature of 55 ° C. Characterization was done by looking at the cell and colony morphology, physiological and biochemical properties. Identification was done with the Profile Matching method based on the reference genus Oscillospira traced through Bergey's Manual of Determinative Bacteriology. Dendogram was created based on similarity index SSM. The results showed there were 14 isolates of bacteria that were able to dissolve phosphate indicated by a clear zone surrounding the bacterial colony on selective media. Five isolates were selected with the largest clear zone. Isolates D79, D92, D110a, D135 and D75 have different characters. The result of phenotypic characters identification with Genus Oscillospira profile has a percentage of 100% similarity to isolate D92 and D110a; 92.31% for isolates D79, and 84.6% for isolates D75 and D135. Dendogram generated from average linkage algorithm / UPGMA using the Simple Matching Coefficient (SSM) algorithms showed, isolate thermophilic bacteria D75 and D135 are combined together to form cluster 1. D110a and D92 form a sub cluster A. Sub cluster A and D79 form cluster 2

Deployable micro-traps to sequester motile bacteria

Science.gov (United States)

di Giacomo, Raffaele; Krödel, Sebastian; Maresca, Bruno; Benzoni, Patrizia; Rusconi, Roberto; Stocker, Roman; Daraio, Chiara

2017-04-01

The development of strategies to reduce the load of unwanted bacteria is a fundamental challenge in industrial processing, environmental sciences and medical applications. Here, we report a new method to sequester motile bacteria from a liquid, based on passive, deployable micro-traps that confine bacteria using micro-funnels that open into trapping chambers. Even in low concentrations, micro-traps afford a 70% reduction in the amount of bacteria in a liquid sample, with a potential to reach >90% as shown by modelling improved geometries. This work introduces a new approach to contain the growth of bacteria without chemical means, an advantage of particular importance given the alarming growth of pan-drug-resistant bacteria.

Dose and time response of ruminally infused algae on rumen fermentation characteristics, biohydrogenation and Butyrivibrio group bacteria in goats.

Science.gov (United States)

Zhu, Honglong; Fievez, Veerle; Mao, Shengyong; He, Wenbo; Zhu, Weiyun

2016-01-01

Micro-algae could inhibit the complete rumen BH of dietary 18-carbon unsaturated fatty acid (UFAs). This study aimed to examine dose and time responses of algae supplementation on rumen fermentation, biohydrogenation and Butyrivibrio group bacteria in goats. Six goats were used in a repeated 3 × 3 Latin square design, and offered a fixed diet. Algae were infused through rumen cannule with 0 (Control), 6.1 (L-Alg), or 18.3 g (H-Alg) per day. Rumen contents were sampled on d 0, 3, 7, 14 and 20. H-Alg reduced total volatile fatty acid concentration and acetate molar proportion (P Algae induced a dose-dependent decrease in 18:0 and increased trans-18:1 in the ruminal content (P Algae had no effect on the abundances of Butyrivibrio spp. and Butyrivibrio proteoclasticus (P > 0.10), while H-Alg reduced the total bacteria abundance (P algae were related to the supplementation level, but there was no evidence of shift in ruminal biohydrogenation pathways towards t10-18:1. L-Alg mainly induced a transient effect on rumen biohydrogenation of 18-carbon UFAs, while H-Alg showed an acute inhibition and these effects were not associated with the known hydrogenating bacteria.

Electron beam fabrication of a microfluidic device for studying submicron-scale bacteria

Science.gov (United States)

2013-01-01

Background Controlled restriction of cellular movement using microfluidics allows one to study individual cells to gain insight into aspects of their physiology and behaviour. For example, the use of micron-sized growth channels that confine individual Escherichia coli has yielded novel insights into cell growth and death. To extend this approach to other species of bacteria, many of whom have dimensions in the sub-micron range, or to a larger range of growth conditions, a readily-fabricated device containing sub-micron features is required. Results Here we detail the fabrication of a versatile device with growth channels whose widths range from 0.3 μm to 0.8 μm. The device is fabricated using electron beam lithography, which provides excellent control over the shape and size of different growth channels and facilitates the rapid-prototyping of new designs. Features are successfully transferred first into silicon, and subsequently into the polydimethylsiloxane that forms the basis of the working microfluidic device. We demonstrate that the growth of sub-micron scale bacteria such as Lactococcus lactis or Escherichia coli cultured in minimal medium can be followed in such a device over several generations. Conclusions We have presented a detailed protocol based on electron beam fabrication together with specific dry etching procedures for the fabrication of a microfluidic device suited to study submicron-sized bacteria. We have demonstrated that both Gram-positive and Gram-negative bacteria can be successfully loaded and imaged over a number of generations in this device. Similar devices could potentially be used to study other submicron-sized organisms under conditions in which the height and shape of the growth channels are crucial to the experimental design. PMID:23575419

Waste package designs for disposal of high-level waste in salt formations

International Nuclear Information System (INIS)

Basham, S.J. Jr.; Carr, J.A.

1984-01-01

In the United States of America the selected method for disposal of radioactive waste is mined repositories located in suitable geohydrological settings. Currently four types of host rocks are under consideration: tuff, basalt, crystalline rock and salt. Development of waste package designs for incorporation in mined salt repositories is discussed. The three pertinent high-level waste forms are: spent fuel, as disassembled and close-packed fuel pins in a mild steel canister; commercial high-level waste (CHLW), as borosilicate glass in stainless-steel canisters; defence high-level waste (DHLW), as borosilicate glass in stainless-steel canisters. The canisters are production and handling items only. They have no planned long-term isolation function. Each waste form requires a different approach in package design. However, the general geometry and the materials of the three designs are identical. The selected waste package design is an overpack of low carbon steel with a welded closure. This container surrounds the waste forms. Studies to better define brine quantity and composition, radiation effects on the salt and brines, long-term corrosion behaviour of the low carbon steel, and the leaching behaviour of the spent fuel and borosilicate glass waste forms are continuing. (author)

COMPETITION BETWEEN ANOXYGENIC PHOTOTROPHIC BACTERIA AND COLORLESS SULFUR BACTERIA IN A MICROBIAL MAT

NARCIS (Netherlands)

VISSCHER, PT; VANDENENDE, FP; SCHAUB, BEM; VANGEMERDEN, H

The populations of chemolithoautotrophic (colorless) sulfur bacteria and anoxygenic phototrophic bacteria were enumerated in a marine microbial mat. The highest population densities were found in the 0-5 mm layer of the mat: 2.0 X 10(9) cells CM-3 sediment, and 4.0 X 10(7) cells cm-3 sediment for

Quorum sensing in gram-negative bacteria

DEFF Research Database (Denmark)

Wu, H.; Song, Z.J.; Høiby, N.

2004-01-01

Bacteria can communicate with each other by means of signal molecules to coordinate the behavior of the entire community, and the mechanism is referred to as quorum sensing (QS). Signal systems enable bacteria to sense the size of their densities by monitoring the concentration of the signal...... molecules. Among Gram-negative bacteria N-acyl-L-homoserine lactone (acyl-HSL)-dependent quorum sensing systems are particularly widespread. These systems are used to coordinate expression of phenotypes that are fundamental to the interaction of bacteria with each other and with their environment...

Indigenous bacteria and bacterial metabolic products in the gastrointestinal tract of broiler chickens.

Science.gov (United States)

Rehman, Habib Ur; Vahjen, Wilfried; Awad, Wageha A; Zentek, Jürgen

2007-10-01

The gastrointestinal tract is a dynamic ecosystem containing a complex microbial community. In this paper, the indigenous intestinal bacteria and the microbial fermentation profile particularly short chain fatty acids (SCFA), lactate, and ammonia concentrations are reviewed. The intestinal bacterial composition changes with age. The bacterial density of the small intestine increases with age and comprises of lactobacilli, streptococci, enterobacteria, fusobacteria and eubacteria. Strict anaerobes (anaerobic gram-positive cocci, Eubacterium spp., Clostridium spp., Lactobacillus spp., Fusobacterium spp. and Bacteroides) are predominating caecal bacteria in young broilers. Data from culture-based studies showed that bifidobacteria could not be isolated from young birds, but were recovered from four-week-old broilers. Caecal lactobacilli accounted for 1.5-24% of the caecal bacteria. Gene sequencing of caecal DNA extracts showed that the majority of bacteria belonged to Clostridiaceae. Intestinal bacterial community is influenced by the dietary ingredients, nutrient levels and physical structure of feed. SCFA and other metabolic products are affected by diet formulation and age. Additional studies are required to know the bacterial metabolic activities together with the community analysis of the intestinal bacteria. Feed composition and processing have great potential to influence the activities of intestinal bacteria towards a desired direction in order to support animal health, well-being and microbial safety of broiler meat.

Comparing identically designed grayscale (50 phase level) and binary (5 phase levels) splitters: actual versus modeled performance

Science.gov (United States)

Lizotte, Todd E.; Ohar, Orest P.; Tuttle, Tracie

2006-04-01

Performance of diffractive optics is determined by high-quality design and a suitable fabrication process that can actually realize the design. Engineers who are tasked with developing or implementing a diffractive optic solution into a product need to take into consideration the risks of using grayscale versus binary fabrication processes. In many cases, grayscale design doesn't always provide the best solution or cost benefit during product development. This fabrication dilemma arises when the engineer has to select a source for design and/or fabrication. Engineers come face to face with reality in view of the fact that diffractive optic suppliers tend to provide their services on a "best effort basis". This can be very disheartening to an engineer who is trying to implement diffractive optics. This paper will compare and contrast the design and performance of a 1 to 24 beam, two dimensional; beam splitter fabricated using a fifty (50) phase level grayscale and a five (5) phase level binary fabrication methods. Optical modeling data will be presented showing both designs and the performance expected prior to fabrication. An overview of the optical testing methods used will be discussed including the specific test equipment and metrology techniques used to verify actual optical performance and fabricated dimensional stability of each optical element. Presentation of the two versions of the splitter will include data on fabrication dimensional errors, split beam-to-beam uniformity, split beam-to-beam spatial size uniformity and splitter efficiency as compared to the original intended design performance and models. This is a continuation of work from 2005, Laser Beam Shaping VI.

Performance of a Heating Block System Designed for Studying the Heat Resistance of Bacteria in Foods

Science.gov (United States)

Kou, Xiao-xi; Li, Rui; Hou, Li-xia; Huang, Zhi; Ling, Bo; Wang, Shao-jin

2016-01-01

Knowledge of bacteria’s heat resistance is essential for developing effective thermal treatments. Choosing an appropriate test method is important to accurately determine bacteria’s heat resistances. Although being a major factor to influence the thermo-tolerance of bacteria, the heating rate in samples cannot be controlled in water or oil bath methods due to main dependence on sample’s thermal properties. A heating block system (HBS) was designed to regulate the heating rates in liquid, semi-solid and solid foods using a temperature controller. Distilled water, apple juice, mashed potato, almond powder and beef were selected to evaluate the HBS’s performance by experiment and computer simulation. The results showed that the heating rates of 1, 5 and 10 °C/min with final set-point temperatures and holding times could be easily and precisely achieved in five selected food materials. A good agreement in sample central temperature profiles was obtained under various heating rates between experiment and simulation. The experimental and simulated results showed that the HBS could provide a sufficiently uniform heating environment in food samples. The effect of heating rate on bacterial thermal resistance was evaluated with the HBS. The system may hold potential applications for rapid and accurate assessments of bacteria’s thermo-tolerances. PMID:27465120

Effects of yeasts and bacteria on the levels of folates in rye sourdoughs.

Science.gov (United States)

Kariluoto, Susanna; Aittamaa, Marja; Korhola, Matti; Salovaara, Hannu; Vahteristo, Liisa; Piironen, Vieno

2006-02-01

Fermentation of rye dough is often accompanied with an increase in folate content. In this study, three sourdough yeasts, Candida milleri CBS 8195, Saccharomyces cerevisiae TS 146, and Torulaspora delbrueckii TS 207; a control, baker's yeast S. cerevisiae ALKO 743; and four Lactobacillus spp., L. acidophilus TSB 262, L. brevis TSB 307, L. plantarum TSB 304, and L. sanfranciscensis TSB 299 originally isolated from rye sourdough were examined for their abilities to produce or consume folates. The microorganisms were grown in yeast extract-peptone-d-glucose medium as well as in small-scale fermentations that modelled the sourdough fermentation step used in rye baking. Total folate contents were determined using Lactobacillus rhamnosus (ATCC 7469) as the growth indicator organism. The microorganisms studied did not excrete folates into the media in significant amounts. Yeasts increased the folate contents of sterilised rye flour-water mixtures from 6.5 microg/100 g to between 15 and 23 microg/100 g after 19-h fermentation, whereas lactic acid bacteria decreased it to between 2.9 and 4.2 microg/100 g. Strains of Lactobacillus bulgaricus, L. casei, L. curvatus, L. fermentum, L. helveticus, Pediococcus spp., and Streptococcus thermophilus that were also tested gave folate contents after fermentation that varied between 2 and 10.4 microg/100 g. Although the four Lactobacillus spp. from sourdough consumed folates their effect on folate contents in co-cultivations was minimal. It was concluded that the increase of folate content during fermentation was mainly due to folate synthesis by yeasts. Fermentation of non-sterilised flour-water mixtures as such resulted in three-fold increases in the folate contents. Two folate producing bacteria were isolated from the non-sterilised flour and identified as Enterobacter cowanii and Pantoea agglomerans.

Metal and antibiotic-resistance in psychrotrophic bacteria from Antarctic marine waters

Digital Repository Service at National Institute of Oceanography (India)

De; Nair, S.; LokaBharathi, P.A.; Chandramohan, D.

In the wake of the findings that Antarctic krills concentrate heavy metals at ppm level, (Yamamoto et al., 1987), the Antarctic waters from the Indian side were examined for the incidence of metal and antibiotic-resistant bacteria during...

Detection of Enteropathogenic Bacteria under Fingernails of Canteen Workers at Universitas Padjadjaran, Jatinangor

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Nalinie Nalammah Nahenthran

2016-06-01

Full Text Available Background: Food poisoning is a major problem in Indonesia as most people do not clean under their fingernails to remove bacteria. This study was designed to detect enteropathogenic bacteria under the fingernails of canteen workers in Universitas Padjadjaran, Jatinangor. Methods: A cross-sectional study was conducted from October−November 2014 at the Faculty of Medicine’s Microbiology Laboratory to detect enteropathogenic bacteria under the fingernails of canteen workers in Universitas Padjadjaran, Jatinangor. Based on the inclusion and exclusion criteria of the study, 30 canteen workers were selected by random sampling from three canteens. Samples were collected from the fingernails of both the right and left hands by using a cotton swab. Sixty specimens were cultured for identification of the enteropathogenic bacteria by using gram staining method and biochemical tests. Results: The highest percentage of enteropathogenic bacteria found under the fingernails of canteen workers was Klebsiella pneumoniae with a percentage of 45% followed by Enterobacter aerogenes with a percentage of 25.7%, Salmonella paratyphii with a percentage of 9.7%, E. coli with a percentage of 6.4%, and Serratia sp, Proteus mirabillis, Klebsiella oxytoca and Shigella sp. with a percentage of 3.2%. Conclusions: The highest number of bacteria found under the fingernails of the canteen workers is Klebsiella pneumoniae, followed by Enterobacter aerogenes, Salmonella paratyphii and E. coli which has potential to cause gastroenteritis if cross-contamination occurs between the fingernails and the food.

Laser-Based Identification of Pathogenic Bacteria

Science.gov (United States)

Rehse, Steven J.

2009-01-01

Bacteria are ubiquitous in our world. From our homes, to our work environment, to our own bodies, bacteria are the omnipresent although often unobserved companions to human life. Physicists are typically untroubled professionally by the presence of these bacteria, as their study usually falls safely outside the realm of our typical domain. In the…

Molecular Identification of Bacteria from Aseptically Loose Implants

Science.gov (United States)

Kobayashi, Naomi; Procop, Gary W.; Krebs, Viktor; Kobayashi, Hideo

2008-01-01

Polymerase chain reaction (PCR) assays have been used to detect bacteria adherent to failed orthopaedic implants, but some PCR assays have had problems with probable false-positive results. We used a combination of a Staphylococcus species-specific PCR and a universal PCR followed by DNA sequencing to identify bacteria on implants retrieved from 52 patients (92 implants) at revision arthroplasty. We addressed two questions in this study: (1) Is this method able to show the existence of bacterial DNA on presumed aseptic loosed implants?; and (2) What proportion of presumed aseptic or culture-negative implants was positive for bacterial DNA by PCR? Fourteen implants (15%) were believed infected, whereas 74 implants (85%) were believed aseptic. Each implant was sonicated and the resulting solution was submitted for dual real-time PCR assay and culture. All implants believed aseptically loose were culture-negative, but nine of the 74 (12%) had bacterial DNA by PCR; two (2.7%) were PCR-positive and also showed histologic findings suggestive of infection. Uniquely developed PCR and bacterial sequencing assays showed bacterial DNA on 12% of implants removed for presumed aseptic loosening. Additional studies are needed to determine the clinical importance of bacterial DNA detected by PCR but not by conventional culture. Level of Evidence: Level III, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence. PMID:18438724

Coliform Bacteria Monitoring in Fish Systems: Current Practices in Public Aquaria.

Science.gov (United States)

Culpepper, Erin E; Clayton, Leigh A; Hadfield, Catherine A; Arnold, Jill E; Bourbon, Holly M

2016-06-01

Public aquaria evaluate coliform indicator bacteria levels in fish systems, but the purpose of testing, testing methods, and management responses are not standardized, unlike with the coliform bacteria testing for marine mammal enclosures required by the U.S. Department of Agriculture. An online survey was sent to selected aquaria to document current testing and management practices in fish systems without marine mammals. The information collected included indicator bacteria species, the size and type of systems monitored, the primary purpose of testing, sampling frequency, test methods, the criteria for interpreting results, corrective actions, and management changes to limit human exposure. Of the 25 institutions to which surveys were sent, 19 (76%) responded. Fourteen reported testing for fecal indicator bacteria in fish systems. The most commonly tested indicator species were total (86%) and fecal (79%) coliform bacteria, which were detected by means of the membrane filtration method (64%). Multiple types and sizes of systems were tested, and the guidelines for testing and corrective actions were highly variable. Only three institutions performed additional tests to confirm the identification of indicator organisms. The results from this study can be used to compare bacterial monitoring practices and protocols in fish systems, as an aid to discussions relating to the accuracy and reliability of test results, and to help implement appropriate management responses. Received August 23, 2015; accepted December 29, 2015.

Characterization of spoilage bacteria in pork sausage by PCR-DGGE analysis

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Francesca Silva Dias

2013-09-01

Full Text Available To investigate microbial diversity and identify spoilage bacteria in fresh pork sausages during storage, twelve industrial pork sausages of different trademarks were stored at 4 ºC for 0, 14, 28 and 42 days, 80% relative humidity and packaged in sterile plastic bags. Microbiological analysis was performed. The pH and water activity (a w were measured. The culture-independent method performed was the Polymerase Chain Reaction - Denaturing Gradient Gel Electrophoresis (PCR-DGGE. The culture-dependent method showed that the populations of mesophilic bacteria and Lactic Acid Bacteria (LAB increased linearly over storage time. At the end of the storage time, the average population of microorganisms was detected, in general, at the level of 5 log cfu g-1. A significant (P < 0.005 increase was observed in pH and a w values at the end of the storage time. The PCR-DGGE allowed a rapid identification of dominant communities present in sausages. PCR-DGGE discriminated 15 species and seven genera of bacteria that frequently constitute the microbiota in sausage products. The most frequent spoilage bacteria identified in the sausages were Lactobacillus sakei and Brochothrix thermosphacta. The identification of dominant communities present in fresh pork sausages can help in the choice of the most effective preservation method for extending the product shelf-life.

Mimicking Seawater For Culturing Marine Bacteria

DEFF Research Database (Denmark)

Rygaard, Anita Mac; Sonnenschein, Eva; Gram, Lone

2015-01-01

Only about 1% of marine bacteria have been brought into culture using traditional techniques. The purpose of this study was to investigate if mimicking the natural bacterial environment can increase culturability.We used marine substrates containing defined algal polymers or gellan gum as solidif......Only about 1% of marine bacteria have been brought into culture using traditional techniques. The purpose of this study was to investigate if mimicking the natural bacterial environment can increase culturability.We used marine substrates containing defined algal polymers or gellan gum...... as solidifying agents, and enumerated bacteria from seawater and algal exudates. We tested if culturability could be influenced by addition of quorum sensing signals (AHLs). All plates were incubated at 15°C. Bacterial counts (CFU/g) from algal exudates from brown algae were highest on media containing algal...... polymers. In general, bacteria isolated from algal exudates preferred more rich media than bacteria isolated from seawater. Overall, culturability ranged from 0.01 to 0.8% as compared to total cell count. Substitution of agar with gellan gum increased the culturability of seawater bacteria approximately...

Antibiotic-resistant bacteria in drinking water.

Science.gov (United States)

Armstrong, J L; Shigeno, D S; Calomiris, J J; Seidler, R J

1981-08-01

We analyzed drinking water from seven communities for multiply antibiotic-resistant (MAR) bacteria (bacteria resistant to two or more antibiotics) and screened the MAR bacterial isolates obtained against five antibiotics by replica plating. Overall, 33.9% of 2,653 standard plate count bacteria from treated drinking waters were MAR. Two different raw water supplies for two communities carried MAR standard plate count bacteria at frequencies of 20.4 and 18.6%, whereas 36.7 and 67.8% of the standard plate count populations from sites within the respective distribution systems were MAR. Isolate identification revealed that MAR gram-positive cocci (Staphylococcus) and MAR gram-negative, nonfermentative rods (Pseudomonas, Alcaligenes, Moraxella-like group M, and Acinetobacter) were more common in drinking waters than in untreated source waters. Site-to-site variations in generic types and differences in the incidences of MAR organisms indicated that shedding of MAR bacteria living in pipelines may have contributed to the MAR populations in tap water. We conclude that the treatment of raw water and its subsequent distribution select for standard plate count bacteria exhibiting the MAR phenotype.

Analysis of some functional properties of acetic acid bacteria ...

African Journals Online (AJOL)

SARAH

2014-03-31

Mar 31, 2014 ... Acetic acid bacteria in Côte d'Ivoire cocoa fermentation ... Six day heap fermentation on banana leaves was conducted at farm level ... reactions responsible for the final quality of the ... harvested from Agboville (geographic coordinates 5°59' .... Figure 1: Evolution of temperature (A) and pH (B) during cocoa ...

Quorum sensing signaling molecules produced by reference and emerging soft-rot bacteria (Dickeya and Pectobacterium spp..

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Alexandre Crépin

Full Text Available Several small diffusible molecules are involved in bacterial quorum sensing and virulence. The production of autoinducers-1 and -2, quinolone, indole and γ-amino butyrate signaling molecules was investigated in a set of soft-rot bacteria belonging to six Dickeya or Pectobacterium species including recent or emerging potato isolates.Using bacterial biosensors, immunoassay, and chromatographic analysis, we showed that soft-rot bacteria have the common ability to produce transiently during their exponential phase of growth the N-3-oxo-hexanoyl- or the N-3-oxo-octanoyl-l-homoserine lactones and a molecule of the autoinducer-2 family. Dickeya spp. produced in addition the indole-3-acetic acid in tryptophan-rich conditions. All these signaling molecules have been identified for the first time in the novel Dickeya solani species. In contrast, quinolone and γ-amino butyrate signals were not identified and the corresponding synthases are not present in the available genomes of soft-rot bacteria. To determine if the variations of signal production according to growth phase could result from expression modifications of the corresponding synthase gene, the respective mRNA levels were estimated by reverse transcriptase-PCR. While the N-acyl-homoserine lactone production is systematically correlated to the synthase expression, that of the autoinducer-2 follows the expression of an enzyme upstream in the activated methyl cycle and providing its precursor, rather than the expression of its own synthase.Despite sharing the S-adenosylmethionine precursor, no strong link was detected between the production kinetics or metabolic pathways of autoinducers-1 and -2. In contrast, the signaling pathway of autoinducer-2 seems to be switched off by the indole-3-acetic acid pathway under tryptophan control. It therefore appears that the two genera of soft-rot bacteria have similarities but also differences in the mechanisms of communication via the diffusible molecules

Quorum Sensing Signaling Molecules Produced by Reference and Emerging Soft-Rot Bacteria (Dickeya and Pectobacterium spp.)

Science.gov (United States)

Crépin, Alexandre; Barbey, Corinne; Beury-Cirou, Amélie; Hélias, Valérie; Taupin, Laure; Reverchon, Sylvie; Nasser, William; Faure, Denis; Dufour, Alain; Orange, Nicole; Feuilloley, Marc; Heurlier, Karin; Burini, Jean-François; Latour, Xavier

2012-01-01

Background Several small diffusible molecules are involved in bacterial quorum sensing and virulence. The production of autoinducers-1 and -2, quinolone, indole and γ-amino butyrate signaling molecules was investigated in a set of soft-rot bacteria belonging to six Dickeya or Pectobacterium species including recent or emerging potato isolates. Methodology/Principal Findings Using bacterial biosensors, immunoassay, and chromatographic analysis, we showed that soft-rot bacteria have the common ability to produce transiently during their exponential phase of growth the N-3-oxo-hexanoyl- or the N-3-oxo-octanoyl-l-homoserine lactones and a molecule of the autoinducer-2 family. Dickeya spp. produced in addition the indole-3-acetic acid in tryptophan-rich conditions. All these signaling molecules have been identified for the first time in the novel Dickeya solani species. In contrast, quinolone and γ-amino butyrate signals were not identified and the corresponding synthases are not present in the available genomes of soft-rot bacteria. To determine if the variations of signal production according to growth phase could result from expression modifications of the corresponding synthase gene, the respective mRNA levels were estimated by reverse transcriptase-PCR. While the N-acyl-homoserine lactone production is systematically correlated to the synthase expression, that of the autoinducer-2 follows the expression of an enzyme upstream in the activated methyl cycle and providing its precursor, rather than the expression of its own synthase. Conclusions/Significance Despite sharing the S-adenosylmethionine precursor, no strong link was detected between the production kinetics or metabolic pathways of autoinducers-1 and -2. In contrast, the signaling pathway of autoinducer-2 seems to be switched off by the indole-3-acetic acid pathway under tryptophan control. It therefore appears that the two genera of soft-rot bacteria have similarities but also differences in the

Production of Bioethanol From Lignocellulosic Biomass Using Thermophilic Anaerobic Bacteria

DEFF Research Database (Denmark)

Georgieva, Tania I.

2006-01-01

and xylose and to tolerate the inhibitory compounds present in lignocellulosic hydrolysates is therefore apparent. Several thermophilic anaerobic xylan degrading bacteria from our culture collection (EMB group at BioCentrum-DTU) have been screened for a potential ethanol producer from hemicellulose...... hydrolysates, and out of the screening test, one particular strain (A10) was selected for the best performance. The strain was morphologically and physiologically characterized as Thermoanaerobacter mathranii strain A10. Unlike other thermophilic anaerobic bacteria, the wild-type strain Thermoanaerobacter...... Thermoanaerobacter BG1L1 was further studied. The experiments were carried out in a continuous immobilized reactor system (a fluidized bed reactor), which is likely to be the process design configuration for xylose fermentation in a Danish biorefinery concept for production of fuel ethanol. The immobilization...

THE PHOTODYNAMIC EFFECT OF LED-MAGNETIC EXPOSURE TO PHOTOINACTIVATION OF AEROBIC PHOTOSYNTETIC BACTERIA

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Suryani Dyah Astuti

2014-01-01

Full Text Available All photosynthetic bacteria have a major pigment of bacteriochlorophyl and accessor pigment e.g. the carotenoids, which both have an important role in photosynthesis process. This study aim to explore the exogenous organic photosensitizer from photosyntetic bacteria for photodynamic therapy application. This study is an experimental research aiming to test the potential illumination ofLED with wavelength 409, 430, 528 and 629 nm, and power optimization and time exposure LED-magnetic for optimum photo activation Rhodococcus growth. The reseach design use a factorial completely randomized design with factor ofpower and exposure time. The number ofbacterial colonies grown measure using ofTotal Plate Count (TPC methods. The result ofanova test shows that irradiation treatment with LED 409 nm, 430 nm, 528 nm and 629 nm significantly affects on bacterial colony growth. LED 409 nm exposure has the greatest potential to boost the growth ofbacterial colonies by 77%. LED exposure and the addition of1.8 mT magnetic field increases bacterial colony growth by 98%. Results of optimization of LED and magnetic fields show power 46 mW and a 40 minute (energy dose 110 J/cm2 optimum growth ofbacterial colonies increase by 184%. So LED and magnetic illumination has potentially increased the viability ofan aerob photosyntetic bacteria colonies.

Mathematical model of rhamnolipid production using E.coli bacteria

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Adham, Muhammad Fariduddin; Apri, Mochamad; Moeis, Maelita Ramdani

2018-03-01

Rhamnolipid is one of biosurfactants that is widely used in many industries. Despite its wide use, production of rhamnolipid usually involves a pathogen that may endanger our health. To tackle this issue, in iGEM (International Genetically Engineered Machine) competition 2015, our team engineered Escherichia coli (E.coli) to produce rhamnolipid. The bacteria were then put into medium containing glucose and lactose. It turned out that bacteria E. coli produced lower rhamnolipid than that by pseudomonas, therefore a good strategy is required to improve their productivity. We present a mathematical model to describe the production of rhamnolipid by the engineered E coli. Using bifurcation analysis, the equilibrium points of the model and their stabilities were analyzed as the amount of lactose was varied. We show that the system produces bistability behavior for some interval values of lactose. From this analysis we found that to guarantee a high production of rhamnolipid, a high level of lactose is required. To maintain the productivity, however, it is sufficient to maintain the lactose level above a certain threshold value.

Pseudomonas mesophilica and an unnamed taxon, clinical isolates of pink-pigmented oxidative bacteria.

Science.gov (United States)

Gilardi, G L; Faur, Y C

1984-10-01

Twenty-one strains of pink-pigmented bacteria, isolated from human clinical specimens and an environmental source, were compared with Pseudomonas mesophilica ATCC 29983 and Protaminobacter ruber ATCC 8457. These isolates were gram-negative, oxidative rods which were motile by means of a single polar flagellum; gave positive catalase, indophenol oxidase, urease, and amylase reactions; and grew slowly at 30 degrees C. Fourteen isolates conformed to the designated type strains Pseudomonas mesophilica ATCC 29983 and Protaminobacter ruber ATCC 8457. The remaining seven strains represented an undescribed taxon. These pink bacteria appear to be invaders of debilitated patients with an underlying chronic disease.

Superparamagnetic nickel colloidal nanocrystal clusters with antibacterial activity and bacteria binding ability

Science.gov (United States)

Peng, Bo; Zhang, Xinglin; Aarts, Dirk G. A. L.; Dullens, Roel P. A.

2018-06-01

Recent progress in synthetic nanotechnology and the ancient use of metals in food preservation and the antibacterial treatment of wounds have prompted the development of nanometallic materials for antimicrobial applications1-4. However, the materials designed so far do not simultaneously display antimicrobial activity and the capability of binding and capturing bacteria and spores. Here, we develop a one-step pyrolysis procedure to synthesize monodisperse superparamagnetic nickel colloidal nanocrystal clusters (SNCNCs), which show both antibacterial activity and the ability to bind Gram-positive (Bacillus subtilis) and Gram-negative (Escherichia coli) bacteria, as well as bacterial spores. The SNCNCs are formed from a rapid burst of nickel nanoparticles, which self-assemble slowly into clusters. The clusters can magnetically extract 99.99% of bacteria and spores and provide a promising approach for the removal of microbes, including hard-to-treat microorganisms. We believe that our work illustrates the exciting opportunities that nanotechnology offers for alternative antimicrobial strategies and other applications in microbiology.

Sulfate-reducing bacteria colonize pouches formed for ulcerative colitis but not for familial adenomatous polyposis.

LENUS (Irish Health Repository)

Duffy, M

2012-02-03

PURPOSE: Ileal pouch-anal anastomosis remains the "gold standard" in surgical treatment of ulcerative colitis and familial adenomatous polyposis. Pouchitis occurs mainly in patients with a background of ulcerative colitis, although the reasons for this are unknown. The aim of this study was to characterize differences in pouch bacterial populations between ulcerative colitis and familial adenomatous pouches. METHODS: After ethical approval was obtained, fresh stool samples were collected from patients with ulcerative colitis pouches (n = 10), familial adenomatous polyposis (n = 7) pouches, and ulcerative colitis ileostomies (n = 8). Quantitative measurements of aerobic and anaerobic bacteria were performed. RESULTS: Sulfate-reducing bacteria were isolated from 80 percent (n = 8) of ulcerative colitis pouches. Sulfate-reducing bacteria were absent from familial adenomatous polyposis pouches and also from ulcerative colitis ileostomy effluent. Pouch Lactobacilli, Bifidobacterium, Bacteroides sp, and Clostridium perfringens counts were increased relative to ileostomy counts in patients with ulcerative colitis. Total pouch enterococci and coliform counts were also increased relative to ileostomy levels. There were no significant quantitative or qualitative differences between pouch types when these bacteria were evaluated. CONCLUSIONS: Sulfate-reducing bacteria are exclusive to patients with a background of ulcerative colitis. Not all ulcerative colitis pouches harbor sulfate-reducing bacteria because two ulcerative colitis pouches in this study were free of the latter. They are not present in familial adenomatous polyposis pouches or in ileostomy effluent collected from patients with ulcerative colitis. Total bacterial counts increase in ulcerative colitis pouches after stoma closure. Levels of Lactobacilli, Bifidobacterium, Bacteroides sp, Clostridium perfringens, enterococci, and coliforms were similar in both pouch groups. Because sulfate-reducing bacteria are

Putative periodontopathic bacteria and herpesviruses in pregnant women: a case-control study.

Science.gov (United States)

Lu, Haixia; Zhu, Ce; Li, Fei; Xu, Wei; Tao, Danying; Feng, Xiping

2016-06-15

Little is known about herpesvirus and putative periodontopathic bacteria in maternal chronic periodontitis. The present case-control study aimed to explore the potential relationship between putative periodontopathic bacteria and herpesviruses in maternal chronic periodontitis.Saliva samples were collected from 36 pregnant women with chronic periodontitis (cases) and 36 pregnant women with healthy periodontal status (controls). Six putative periodontopathic bacteria (Porphyromonas gingivalis [Pg], Aggregatibacer actinomycetemcomitans [Aa], Fusobacterium nucleatum [Fn], Prevotella intermedia [Pi], Tannerella forsythia [Tf], and Treponema denticola [Td]) and three herpesviruses (Epstein-Barr virus [EBV], human cytomegalovirus [HCMV], and herpes simplex virus [HSV]) were detected. Socio-demographic data and oral health related behaviors, and salivary estradiol and progesterone levels were also collected. The results showed no significant differences in socio-demographic background, oral health related behaviors, and salivary estradiol and progesterone levels between the two groups (all P > 0.05). The detection rates of included periodontopathic microorganisms were not significantly different between the two groups (all P > 0.05), but the coinfection rate of EBV and Pg was significantly higher in the case group than in the control group (P = 0.028). EBV and Pg coinfection may promote the development of chronic periodontitis among pregnant women.

Characterization of culturable bacteria isolated from the cold-water coral Lophelia pertusa

Science.gov (United States)

Galkiewicz, Julia P.; Pratte, Zoe A.; Gray, Michael A.; Kellogg, Christina A.

2011-01-01

Microorganisms associated with corals are hypothesized to contribute to the function of the host animal by cycling nutrients, breaking down carbon sources, fixing nitrogen, and producing antibiotics. This is the first study to culture and characterize bacteria from Lophelia pertusa, a cold-water coral found in the deep sea, in an effort to understand the roles that the microorganisms play in the coral microbial community. Two sites in the northern Gulf of Mexico were sampled over 2 years. Bacteria were cultured from coral tissue, skeleton, and mucus, identified by 16S rRNA genes, and subjected to biochemical testing. Most isolates were members of the Gammaproteobacteria, although there was one isolate each from the Betaproteobacteria and Actinobacteria. Phylogenetic results showed that both sampling sites shared closely related isolates (e.g. Pseudoalteromonas spp.), indicating possible temporally and geographically stable bacterial-coral associations. The Kirby-Bauer antibiotic susceptibility test was used to separate bacteria to the strain level, with the results showing that isolates that were phylogenetically tightly grouped had varying responses to antibiotics. These results support the conclusion that phylogenetic placement cannot predict strain-level differences and further highlight the need for culture-based experiments to supplement culture-independent studies.

Phylogenetic Evidence for the Existence of Novel Thermophilic Bacteria in Hot Spring Sulfur-Turf Microbial Mats in Japan

Science.gov (United States)

Yamamoto, Hiroyuki; Hiraishi, Akira; Kato, Kenji; Chiura, Hiroshi X.; Maki, Yonosuke; Shimizu, Akira

1998-01-01

So-called sulfur-turf microbial mats, which are macroscopic white filaments or bundles consisting of large sausage-shaped bacteria and elemental sulfur particles, occur in sulfide-containing hot springs in Japan. However, no thermophiles from sulfur-turf mats have yet been isolated as cultivable strains. This study was undertaken to determine the phylogenetic positions of the sausage-shaped bacteria in sulfur-turf mats by direct cloning and sequencing of 16S rRNA genes amplified from the bulk DNAs of the mats. Common clones with 16S rDNA sequences with similarity levels of 94.8 to 99% were isolated from sulfur-turf mat samples from two geographically remote hot springs. Phylogenetic analysis showed that the phylotypes of the common clones formed a major cluster with members of the Aquifex-Hydrogenobacter complex, which represents the most deeply branching lineage of the domain bacteria. Furthermore, the bacteria of the sulfur-turf mat phylotypes formed a clade distinguishable from that of other members of the Aquifex-Hydrogenobacter complex at the order or subclass level. In situ hybridization with clone-specific probes for 16S rRNA revealed that the common phylotype of sulfur-turf mat bacteria is that of the predominant sausage-shaped bacteria. PMID:9572936

EFFICACY OF ENDOPHYTIC BACTERIA IN REDUCING PLANT PARASITIC NEMATODE Pratylenchus brachyurus

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Rita Harni

2014-04-01

Full Text Available Pratylenchus brachyurus is a major parasitic nematode on patchouli that reduces plant production up to 85%. The use of endophytic bacteria is promising for controlling nematode and promoting plant growth through production of phytohormones and enhancing the availability of soil nutrients. The objective of the study was to evaluate the efficacy of endophytic bacteria to control P. brachyurus on patchouli plant and its influence on plant productions (plant fresh weight and patchouli oil. The study was conducted at Cimanggu Experimental Garden and Laboratory of the Indonesian Spice and Medicinal Crops Research Institute (ISMECRI, Bogor, West Java. The experi-ment was designed in a randomized block with seven treatments and eight replications; each replication consisted of 10 plants. The treatments evaluated were five isolates of endophytic bacteria (Achromobacter xylosoxidans TT2, Alcaligenes faecalis NJ16, Pseudomonas putida EH11, Bacillus cereus MSK and Bacillus subtilis NJ57, synthetic nematicide as a reference, and non-treated plant as a control.  Four-week old patchouli plants of cv. Sidikalang were treated by soaking the roots in suspension of endophytic bacteria (109 cfu  ml-1 for one hour before trans-planting to the field. At one month after planting, the plants were drenched with the bacterial suspension as much as 100 ml per plant. The results showed that applications of the endophytic bacteria could suppress the nematode populations (52.8-80% and increased plant weight (23.62-57.48% compared to the control. The isolate of endophytic bacterium Achromobacter xylosoxidans TT2 was the best and comparable with carbofuran.

Genetic transformation of midgut bacteria from the red imported fire ant (Solenopsis invicta).

Science.gov (United States)

Medina, Freder; Li, Haiwen; Vinson, S Bradleigh; Coates, Craig J

2009-05-01

In our previous study we isolated 10 bacterial species from fourth-instar larval midguts of the red imported fire ant, Solenopsis invicta. Here we report the genetic transformation and reintroduction of three species (Kluyvera cryocrescens, Serratia marcescens, and isolate 38) into the fire ant host. All three species were transformed with the plasmid vector, pZeoDsRed. High expression levels of DsRed were observed and the plasmid is maintained in these bacteria at 37 degrees C in the absence of antibiotic selection for at least 9 days of subculturing. The transformed bacteria were successfully reintroduced into fire ant larvae and survived in the fire ant gut for at least 7 days. Upon pupal emergence, 7 days after reintroduction, transformed bacteria can still be isolated, however, most were passed out in the meconium. We further demonstrated that the engineered bacteria could be spread within the colony by feeding this meconium to naive larvae with the aid of worker fire ants.

Bacteria Facilitate Enteric Virus Co-infection of Mammalian Cells and Promote Genetic Recombination.

Science.gov (United States)

Erickson, Andrea K; Jesudhasan, Palmy R; Mayer, Melinda J; Narbad, Arjan; Winter, Sebastian E; Pfeiffer, Julie K

2018-01-10

RNA viruses exist in genetically diverse populations due to high levels of mutations, many of which reduce viral fitness. Interestingly, intestinal bacteria can promote infection of several mammalian enteric RNA viruses, but the mechanisms and consequences are unclear. We screened a panel of 41 bacterial strains as a platform to determine how different bacteria impact infection of poliovirus, a model enteric virus. Most bacterial strains, including those extracted from cecal contents of mice, bound poliovirus, with each bacterium binding multiple virions. Certain bacterial strains increased viral co-infection of mammalian cells even at a low virus-to-host cell ratio. Bacteria-mediated viral co-infection correlated with bacterial adherence to cells. Importantly, bacterial strains that induced viral co-infection facilitated genetic recombination between two different viruses, thereby removing deleterious mutations and restoring viral fitness. Thus, bacteria-virus interactions may increase viral fitness through viral recombination at initial sites of infection, potentially limiting abortive infections. Copyright © 2017 Elsevier Inc. All rights reserved.

Metabolic activity of uncultivated magnetotactic bacteria revealed by NanoSIMS

Science.gov (United States)

He, M.; Zhang, W.; Gu, L.; Pan, Y.; Lin, W.

2017-12-01

Microorganisms that exhibit magnetotaxis behavior, collectively known as the magnetotactic bacteria (MTB), are those whose motility is influenced by the Earth's magnetic field. MTB are a physiologically diverse group of bacteria with a unique feature of intracellular biomineralization of magnetosomes (Fe3O4 and/or Fe3S4) (Bazylinski et al., 2013). However, the ecophysiology of uncultivated MTB, especially those within the Nitrospirae phylum forming hundreds of bullet-shaped magnetite magnetosomes per cell, is still not well characterized (Lin et al., 2014). Nanoscale secondary ion mass spectrometry (NanoSIMS) is a powerful tool for revealing element distribution in nanometer-scale resolution, which opens exciting possibilities for the study of interactions between microorganisms and environments (Gao et al., 2016; Musat et al., 2016). Here we applied NanoSIMS to investigate the dynamics of carbon and nitrogen assimilations in two magnetotactic Nitrospirae populations at single cell level. Our NanoSIMS results confirmed the metabolic potential of Nitrospirae MTB proposed by genomic and metagenomic analysis and provided additional insights into the ecophysiology of uncultivated MTB. This study suggests that NanoSIMS-based analyses are powerful approaches for investigating and characterizing the ecological function of environmental microorganisms. References: Bazylinski D A., Lefèvre, C T., Schüler D., 2013. Magnetotactic Bacteria. 453-494.Lin W, Bazylinski DA, Xiao T, Wu L- F, Pan Y., 2014. Life with compass: diversity and biogeography of magnetotactic bacteria. Environ Microbiol, 16: 1462-2920.Gao D., Huang X., Tao Y., 2016. A critical review of NanoSIMS in analysis of microbial metabolic activities at single-cell level. Crit Rev Biotechnol, 36: 884-890.Musat N., Musat F., Weber PK., Pett-Ridge J., 2016. Tracking microbial interactions with NanoSIMS. Curr Opin Biotechnol, 41: 114-121.

Bacteriophages: the possible solution to treat infections caused by pathogenic bacteria.

Science.gov (United States)

El-Shibiny, Ayman; El-Sahhar, Salma

2017-11-01

Since their discovery in 1915, bacteriophages have been used to treat bacterial infections in animals and humans because of their unique ability to infect their specific bacterial hosts without affecting other bacterial populations. The research carried out in this field throughout the 20th century, largely in Georgia, part of USSR and Poland, led to the establishment of phage therapy protocols. However, the discovery of penicillin and sulfonamide antibiotics in the Western World during the 1930s was a setback in the advancement of phage therapy. The misuse of antibiotics has reduced their efficacy in controlling pathogens and has led to an increase in the number of antibiotic-resistant bacteria. As an alternative to antibiotics, bacteriophages have become a topic of interest with the emergence of multidrug-resistant bacteria, which are a threat to public health. Recent studies have indicated that bacteriophages can be used indirectly to detect pathogenic bacteria or directly as biocontrol agents. Moreover, they can be used to develop new molecules for clinical applications, vaccine production, drug design, and in the nanomedicine field via phage display.

The Microworld of Marine-Bacteria

DEFF Research Database (Denmark)

JØRGENSEN, BB

1995-01-01

Microsensor studies show that the marine environment in the size scale of bacteria is physically and chemically very different from the macroenvironment. The microbial world of the sediment-water interface is thus dominated by water viscosity and steep diffusion gradients. Because of the diverse...... metabolism types, bacteria in the mostly anoxic sea floor play an important role in the major element cycles of the ocean. The communities of giant, filamentous sulfur bacteria that live in the deep-sea hydrothermal vents or along the Pacific coast of South America are presented here as examples....

Effect of Different Filling Materials in Anammox Bacteria Enrichment

Directory of Open Access Journals (Sweden)

Dilek ÖZGÜN

2012-12-01

Full Text Available Purpose: Anaerobic ammonium oxidation (Anammox is a process that ammonium as electron donor is oxidized to nitrogen gas using nitrite as electron acceptor. Compared to conventional nitrification-denitrification processes, this process is used less oxygen and no organic material (methanol, glucose. However, the slow growth rate of Anammox bacteria (11-30 days is disadvantages. Therefore, batch reactors have been carried out in these bacteria enrichment. In this study continuously operated upflow anaerobic sludge reactor (UASB using different filling materials disposing of sensitive and slow-growing Anammox bacteria out of the system is purposed. Design and Methods: System is operated up-flow column reactor at 2 days hydraulic retention time (HRT in 45 days. In this study, ceramic stones and Linpor filling material are used. Using synthetic wastewater containing ammonium and nitrite, Ar/CO2 anaerobic conditions (95/5% supplied with gas. System is operated at a temperature 253 C in UASB. Temperature, pH, ammonia-nitrogen and nitrite nitrogen are measured. Results: Both filling material reactors are operated in 45 days. Ceramic stones filling reactor is observed quickly reaches 90% were used reactor ammonium removal. The ammonium nitrogen removal was slower in Linpor filling materials reactor. Nitrite removal is reached up to 90% in both the reactor. When compared to the stoichiometric equation in Linpor was composed of large amounts of nitrate. At the end of 25 days the results were similar to ceramic stone filling reactor with Linpor filling material reactors. Conclusions and Original Value: Anammox process as from nitrogen removal processes was discovered in 1995. Anammox bacteria that make up this process due to very low growth rates of microbial bacteria in the system must be kept in the system. Most of the studies in the literature, these bacteria enrichment stage is started instead of a continuous batch reactor system. In this study

A novel antimicrobial peptide against dental-caries-associated bacteria.

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Chen, Long; Jia, Lili; Zhang, Qiang; Zhou, Xirui; Liu, Zhuqing; Li, Bingjie; Zhu, Zhentai; Wang, Fenwei; Yu, Changyuan; Zhang, Qian; Chen, Feng; Luo, Shi-Zhong

2017-10-01

Dental caries, a highly prevalent oral disease, is primarily caused by pathogenic bacteria infection, and most of them are anaerobic. Herein, we investigated the activity of a designed antimicrobial peptide ZXR-2, and found it showed broad-spectrum activity against a variety of Gram-positive and Gram-negative oral bacteria, particularly the caries-related taxa Streptococcus mutans. Time-course killing assays indicated that ZXR-2 killed most bacterial cells within 5 min at 4 × MIC. The mechanism of ZXR-2 involved disruption of cell membranes, as observed by scanning electron microscopy. Moreover, ZXR-2 inhibited the formation of S. mutans biofilm, but showed limited hemolytic effect. Based on its potent antimicrobial activity, rapid killing, and inhibition of S. mutans biofilm formation, ZXR-2 represents a potential therapeutic for the prevention and treatment of dental caries. Copyright © 2017 Elsevier Ltd. All rights reserved.

Circumvention of Learning Increases Intoxication Efficacy of Nematicidal Engineered Bacteria.

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Bracho, Olena R; Manchery, Cyril; Haskell, Evan C; Blanar, Christopher A; Smith, Robert P

2016-03-18

Synthetic biology holds promise to engineer systems to treat diseases. One critical, yet underexplored, facet of designing such systems is the interplay between the system and the pathogen. Understanding this interplay may be critical to increasing efficacy and overcoming resistance against the system. Using the principles of synthetic biology, we engineer a strain of Escherichia coli to attract and intoxicate the nematode Caenorhabditis elegans. Our bacteria are engineered with a toxin module, which intoxicates the nematode upon ingestion, and an attraction module, which serves to attract and increase the feeding rate of the nematodes. When independently implemented, these modules successfully intoxicate and attract the worms, respectively. However, in combination, the efficacy of our bacteria is significantly reduced due to aversive associative learning in C. elegans. Guided by mathematical modeling, we dynamically regulate module induction to increase intoxication by circumventing learning. Our results detail the creation of a novel nematicidal bacterium that may have application against nematodes, unravel unique constraints on circuit dynamics that are governed by C. elegans physiology, and add to the growing list of design and implementation considerations associated with synthetic biology.

Bacteria of leg atheromatous arteries responsible for inflammation.

Science.gov (United States)

Olszewski, Waldemar Lech; Rutkowska, Joanna; Moscicka-Wesolowska, Maria; Swoboda-Kopec, Ewa; Stelmach, Ewa; Zaleska, Marzanna; Zagozda, Malgorzata

2016-09-01

Ischaemia of the lower limbs is frequently followed by inflammation and, in advanced cases, necrosis of peripheral tissues. Whether this is caused by arterial hypoperfusion only or by the presence of bacteria in the arterial walI as well remains unclear. The aim of the study was to prove the presence and source of bacteria in arterial specimens and evaluate their chemotactic properties resulting in the formation of periarterial cellular infiltrates. Bacterial culture and testing for 16sRNA were performed in fragments of popliteal artery harvested from amputated limbs. Carotid artery plaques served as controls. Fragments of arteries were transplanted into scid mice to evaluate their chemotactic activity for macrophages. a) higher prevalence of isolates and 16sRNA in atherosclerotic popliteal than carotid arteries, b) high density of plaque and periarterial infiltrates and mRNA level for pro-inflammatory cytokines in popliteal arteries, c) prevalent microbes were Staphylococcus aureus, S. epidermidis and Enterococci, d) foot skin and arterial bacterial phenotypes and DNA revealed evident similarities, and e) more intensive mouse macrophage accumulation in popliteal than carotid implants into scid mice. The presence of bacteria in the lower limb arterial wall was documented. They may predispose to inflammation secondary to ischaemic changes.

Magnetotactic bacteria at the geomagnetic equator

International Nuclear Information System (INIS)

Frankel, R.B.; Blakemore, R.P.; Araujo, F.F.T. de; Esquivel, D.M.S.; Danon, J.

1981-01-01

Magnetotatic bacteria are observed in freshwater and marine sediments of Fortaleza, Brazil, situated close to the geomagnetic equator. Both South-seeking and North-seeking bacteria are present in roughly equal numbers in the same samples. This observation is consistent with the hypothesis that the vertical component of the geomagnetic field selects the predominant polarity type among magnetotactic bacteria in natural environments. (Author) [pt

The Effect of Bacteria Penetration on Chalk Permeability

DEFF Research Database (Denmark)

Halim, Amalia Yunita; Shapiro, Alexander; Nielsen, Sidsel Marie

number of B. licheniformis was detected on the effluent compared with P. putida. However, in the experiment with B. licheniformis mainly spores were detected in the effluent. The core permeability decreased rapidly during injection of bacteria and a starvation period of 12 days did not allow......Bacteria selective plugging is one of the mechanisms through which microorganisms can be applied for enhanced oil recovery. Bacteria can plug the water-bearing zones of a reservoir, thus altering the flow paths and improving sweep efficiency. It is known that the bacteria can penetrate deeply...... into reservoirs, however, a complete understanding of the penetration behavior of bacteria is lacking, especially in chalk formations where the pore throat sizes are almost comparable with the sizes of bacteria vegetative cells. This study investigates the penetration of bacteria into chalk. Two bacteria types...

Estimation of Missing Observations in Two-Level Split-Plot Designs

DEFF Research Database (Denmark)

Almimi, Ashraf A.; Kulahci, Murat; Montgomery, Douglas C.

2008-01-01

Inserting estimates for the missing observations from split-plot designs restores their balanced or orthogonal structure and alleviates the difficulties in the statistical analysis. In this article, we extend a method due to Draper and Stoneman to estimate the missing observations from unreplicated...... two-level factorial and fractional factorial split-plot (FSP and FFSP) designs. The missing observations, which can either be from the same whole plot, from different whole plots, or comprise entire whole plots, are estimated by equating to zero a number of specific contrast columns equal...... to the number of the missing observations. These estimates are inserted into the design table and the estimates for the remaining effects (or alias chains of effects as the case with FFSP designs) are plotted on two half-normal plots: one for the whole-plot effects and the other for the subplot effects...

The Study of Isolated Bacteria Application for Bioremediation Agent of Uranium Radionuclide in the Environment

International Nuclear Information System (INIS)

Yazid, Mochd

2007-01-01

Application of the isolated bacteria on the Low Level Uranium Waste as uranium bioremediation agent in the environment has been studied. The objective of this research is to study the possibility of isolated bacteria to be used on uranium remediation process. The isolation of uranium resistance bacteria was carried out on the selective medium SBS containing 10 mg/l uranium, incubated at 37°C until the growth was visible. Selection of binding uranium bacteria was carried out based on their ability to grow on liquid medium containing various concentration of uranium that shacked on 120 rpm speed. The isolated bacteria with the highest specific growth rate constant (μ) were selected for biochemical characterization and identification by matching profile method. The result of this research showed that three selected isolate bacteria were able to grow well on liquid SBS medium until 100 mg/l uranium concentration. The identification results showed that two of them were suspected belong to the genus Pseudomonas and one isolates belong to the genus of Bacillus. The uranium reduction studied was performed by growing up the isolated bacteria on the SBS liquid medium that containing 40 mg/l uranium. Bacterial growth were measured by weighted of bacterial biomass and uranium concentration were measured by spectrophotometer. The research result showed that the selected isolates bacteria may applicable for bioremediation agent because of their ability to grow well on liquid SBS medium and their ability on uranium concentration reduction. The efficiency of reduction by Pseudomonas in the isolated bacteria one were 78.51 % and in the isolated bacteria three were 91.47 % , and Bacillus in the isolate bacteria six were 52.73%. (author)

Estimation of total bacteria by real-time PCR in patients with periodontal disease.

Science.gov (United States)

Brajović, Gavrilo; Popović, Branka; Puletić, Miljan; Kostić, Marija; Milasin, Jelena

2016-01-01

Periodontal diseases are associated with the presence of elevated levels of bacteria within the gingival crevice. The aim of this study was to evaluate a total amount of bacteria in subgingival plaque samples in patients with a periodontal disease. A quantitative evaluation of total bacteria amount using quantitative real-time polymerase chain reaction (qRT-PCR) was performed on 20 samples of patients with ulceronecrotic periodontitis and on 10 samples of healthy subjects. The estimation of total bacterial amount was based on gene copy number for 16S rRNA that was determined by comparing to Ct values/gene copy number of the standard curve. A statistically significant difference between average gene copy number of total bacteria in periodontal patients (2.55 x 10⁷) and healthy control (2.37 x 10⁶) was found (p = 0.01). Also, a trend of higher numbers of the gene copy in deeper periodontal lesions (> 7 mm) was confirmed by a positive value of coefficient of correlation (r = 0.073). The quantitative estimation of total bacteria based on gene copy number could be an important additional tool in diagnosing periodontitis.

Chromate reduction is expedited by bacteria engineered to produce the compatible solute trehalose.

Science.gov (United States)

Frederick, Tamlyn M; Taylor, Erin A; Willis, Jennifer L; Shultz, Matthew S; Woodruff, Peter J

2013-08-01

The toxicity and solubility of chromium(VI) can be decreased by certain microbes that reduce chromium(VI) to chromium(III). However, these bacteria do not escape unscathed from this process. Chromium(VI) reduction damages the essential macromolecules of living systems. Trehalose protects organisms from chemical stress but has not been tested in the context of bioremediation. We engineered bacteria to produce trehalose and found that they then reduced 1 mM chromium(VI) to chromium(III), whereas wild-type cells were only able to reduce half that amount. Thus, by providing bacteria with a biochemical defense against the side-effects of chromate reduction may be a new approach to cleaning up sites that are contaminated with high levels of chromate.

Pathogenic mechanisms of intracellular bacteria.

Science.gov (United States)

Niller, Hans Helmut; Masa, Roland; Venkei, Annamária; Mészáros, Sándor; Minarovits, Janos

2017-06-01

We wished to overview recent data on a subset of epigenetic changes elicited by intracellular bacteria in human cells. Reprogramming the gene expression pattern of various host cells may facilitate bacterial growth, survival, and spread. DNA-(cytosine C5)-methyltransferases of Mycoplasma hyorhinis targeting cytosine-phosphate-guanine (CpG) dinucleotides and a Mycobacterium tuberculosis methyltransferase targeting non-CpG sites methylated the host cell DNA and altered the pattern of gene expression. Gene silencing by CpG methylation and histone deacetylation, mediated by cellular enzymes, also occurred in M. tuberculosis-infected macrophages. M. tuberculosis elicited cell type-specific epigenetic changes: it caused increased DNA methylation in macrophages, but induced demethylation, deposition of euchromatic histone marks and activation of immune-related genes in dendritic cells. A secreted transposase of Acinetobacter baumannii silenced a cellular gene, whereas Mycobacterium leprae altered the epigenotype, phenotype, and fate of infected Schwann cells. The 'keystone pathogen' oral bacterium Porphyromonas gingivalis induced local DNA methylation and increased the level of histone acetylation in host cells. These epigenetic changes at the biofilm-gingiva interface may contribute to the development of periodontitis. Epigenetic regulators produced by intracellular bacteria alter the epigenotype and gene expression pattern of host cells and play an important role in pathogenesis.

Determination of foodborne pathogenic bacteria by multiplex PCR-microchip capillary electrophoresis with genetic algorithm-support vector regression optimization.

Science.gov (United States)

Li, Yongxin; Li, Yuanqian; Zheng, Bo; Qu, Lingli; Li, Can

2009-06-08

A rapid and sensitive method based on microchip capillary electrophoresis with condition optimization of genetic algorithm-support vector regression (GA-SVR) was developed and applied to simultaneous analysis of multiplex PCR products of four foodborne pathogenic bacteria. Four pairs of oligonucleotide primers were designed to exclusively amplify the targeted gene of Vibrio parahemolyticus, Salmonella, Escherichia coli (E. coli) O157:H7, Shigella and the quadruplex PCR parameters were optimized. At the same time, GA-SVR was employed to optimize the separation conditions of DNA fragments in microchip capillary electrophoresis. The proposed method was applied to simultaneously detect the multiplex PCR products of four foodborne pathogenic bacteria under the optimal conditions within 8 min. The levels of detection were as low as 1.2 x 10(2) CFU mL(-1) of Vibrio parahemolyticus, 2.9 x 10(2) CFU mL(-1) of Salmonella, 8.7 x 10(1) CFU mL(-1) of E. coli O157:H7 and 5.2 x 10(1) CFU mL(-1) of Shigella, respectively. The relative standard deviation of migration time was in the range of 0.74-2.09%. The results demonstrated that the good resolution and less analytical time were achieved due to the application of the multivariate strategy. This study offers an efficient alternative to routine foodborne pathogenic bacteria detection in a fast, reliable, and sensitive way.

Intrinsic, adaptive and acquired antimicrobial resistance in Gram-negative bacteria.

Science.gov (United States)

Arzanlou, Mohsen; Chai, Wern Chern; Venter, Henrietta

2017-02-28

Gram-negative bacteria are responsible for a large proportion of antimicrobial-resistant infections in humans and animals. Among this class of bacteria are also some of the most successful environmental organisms. Part of this success is their adaptability to a variety of different niches, their intrinsic resistance to antimicrobial drugs and their ability to rapidly acquire resistance mechanisms. These mechanisms of resistance are not exclusive and the interplay of several mechanisms causes high levels of resistance. In this review, we explore the molecular mechanisms underlying resistance in Gram-negative organisms and how these different mechanisms enable them to survive many different stress conditions. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

In-Use Evaluation of Peracetic Acid for High-Level Disinfection of Endoscopes.

Science.gov (United States)

Chenjiao, Wu; Hongyan, Zhang; Qing, Gu; Xiaoqi, Zhong; Liying, Gu; Ying, Fang

2016-01-01

Many high-level disinfectants have been used for disinfection of endoscopes such as 2% glutaraldehyde (GA), 0.55% ortho-phthalaldehyde (OPA), and peracetic acid (PAA). Both GA and OPA are widely used in disinfection of endoscopes and have been previously discussed, but there is little research on the practical use of PAA as an endoscope disinfectant. An experimental model of a flexible gastrointestinal endoscope being contaminated with 9 strains of microorganism was designed. After the cleaning and disinfecting procedure was completed, we evaluated the biocidal activity (850 ppm PAA, 2% GA, and 0.55% OPA) on our flexible gastrointestinal endoscope model. We also evaluated sterilization effectiveness of PAA on other bacteria, including some antibiotic-resistant bacteria (methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus, and Clostridium difficile). The residual bacterial colony count number of the PAA-disinfected endoscope was significantly lower than that of the GA- and OPA-disinfected endoscopes. The biocidal effect and efficiency of the endoscope disinfection by PAA appeared to be better than either the GA- or OPA-disinfected endoscope. PAA has demonstrated a good sterilization effect on other bacterial species; of particular note are common antibiotic-resistant bacteria such as methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus, and Clostridium difficile. The results of this study demonstrate that PAA is a fast and effective high-level disinfectant for use in the reprocessing of flexible endoscopes.

Innovative designs for low-level nuclear waste disposal trenches

International Nuclear Information System (INIS)

Nowatzki, E.A.; Armstrong, G.; McCray, J.

1985-01-01

Shallow land burial of low-level nuclear wastes presents many problems that are within the scope of civil engineering analysis and design. These include groundwater seepage, surface water runoff and collection, and the subsidence of trench backfills. Unfortunately, at the time the first disposal sites were being developed, major emphasis was placed on the health-physics aspects of the problem with the result that many of the civil engineering aspects were overlooked and severe problems relating to site integrity exist today. This paper presents the results of a U.S. Nuclear Regulatory Commission (USNRC) sponsored research project conducted at the University of Arizona, Tucson, Arizona, to assess trench cap design from the viewpoint of stability, water infiltration, and economy. Full-scale trenches were constructed that incorporated four different designs. These designs range from a relatively simple cap consisting of engineered backfill with a sloping, compacted soil crown to a more complex cap-crown system that incorporates compacted backfill and a steel reinforced soil-cement cap with an overlaying ''wick'' drain. The results of structural and hydrological monitoring over a period of approximately 15 months are presented. Recommendations are made regarding standard design criteria for future sites based on the results of this research

Bioenergetics of photoheterotrophic bacteria in the oceans.

Science.gov (United States)

Kirchman, David L; Hanson, Thomas E

2013-04-01

Photoheterotrophic microbes, such as proteorhodopsin (PR)-based phototrophic (PRP) and aerobic anoxygenic phototrophic (AAP) bacteria, are well known to be abundant in the oceans, potentially playing unique roles in biogeochemical cycles. However, the contribution of phototrophy to the energy requirements of these bacteria has not been quantitatively examined to date. To better understand the implications of photoheterophy in the oceans, we calculated energy benefits and costs of phototrophy and compared net benefits with maintenance costs. Benefits depend on the number of photosynthetic units (PSUs), absorption cross-section area of each PSU as function of wavelength, the in situ light quality, and the energy yield per absorbed photon. For costs we considered the energy required for the synthesis of pigments, amino acids and proteins in each PSU. Our calculations indicate that AAP bacteria harvest more light energy than do PRP bacteria, but the costs of phototrophy are much higher for AAP bacteria. Still, the net energy gained by AAP bacteria is often sufficient to meet maintenance costs, while that is not the case for PRP bacteria except with high light intensities and large numbers of proteorhodopsin molecules per cell. The low costs and simplicity of PR-based phototrophy explain the high abundance of proteorhodopsin genes in the oceans. However, even for AAP bacteria, the net energy yield of phototrophy is apparently too low to influence the distribution of photoheterotrophic bacteria among various marine systems. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

Review of Optimization Strategies for System-Level Design in Hybrid Electric Vehicles

NARCIS (Netherlands)

Silvas, E.; Hofman, T.; Murgovski, N.; Etman, L.F.P.; Steinbuch, M.

2017-01-01

The optimal design of a hybrid electric vehicle (HEV) can be formulated as a multiobjective optimization problem that spreads over multiple levels (technology, topology, size, and control). In the last decade, studies have shown that by integrating these optimization levels, fuel benefits are

Ecophysiology of the Anammox Bacteria

NARCIS (Netherlands)

Kartal, M.B.

2008-01-01

Anaerobic ammonium oxidizing (anammox) bacteria oxidize ammonium to dinitrogen gas with nitrite as the electron acceptor. These bacteria are the key players in the global nitrogen cycle, responsible for the most of nitrogen production in natural ecosystems. The anammox process is also a

Biofilms Formed by Gram-Negative Bacteria Undergo Increased Lipid A Palmitoylation, Enhancing In Vivo Survival

Science.gov (United States)

Chalabaev, Sabina; Chauhan, Ashwini; Novikov, Alexey; Iyer, Pavithra; Szczesny, Magdalena; Beloin, Christophe; Caroff, Martine

2014-01-01

ABSTRACT Bacterial biofilm communities are associated with profound physiological changes that lead to novel properties compared to the properties of individual (planktonic) bacteria. The study of biofilm-associated phenotypes is an essential step toward control of deleterious effects of pathogenic biofilms. Here we investigated lipopolysaccharide (LPS) structural modifications in Escherichia coli biofilm bacteria, and we showed that all tested commensal and pathogenic E. coli biofilm bacteria display LPS modifications corresponding to an increased level of incorporation of palmitate acyl chain (palmitoylation) into lipid A compared to planktonic bacteria. Genetic analysis showed that lipid A palmitoylation in biofilms is mediated by the PagP enzyme, which is regulated by the histone-like protein repressor H-NS and the SlyA regulator. While lipid A palmitoylation does not influence bacterial adhesion, it weakens inflammatory response and enhances resistance to some antimicrobial peptides. Moreover, we showed that lipid A palmitoylation increases in vivo survival of biofilm bacteria in a clinically relevant model of catheter infection, potentially contributing to biofilm tolerance to host immune defenses. The widespread occurrence of increased lipid A palmitoylation in biofilms formed by all tested bacteria suggests that it constitutes a new biofilm-associated phenotype in Gram-negative bacteria. PMID:25139899

Multiparametric Profiling for Identification of Chemosensitizers against Gram-Negative Bacteria

Directory of Open Access Journals (Sweden)

Vincent Lôme

2018-02-01

Full Text Available Antibiotic resistance is now a worldwide therapeutic problem. Since the beginning of anti-infectious treatment bacteria have rapidly shown an incredible ability to develop and transfer resistance mechanisms. In the last decades, the design variation of pioneer bioactive molecules has strongly improved their activity and the pharmaceutical companies partly won the race against the clock. Since the 1980s, the new classes of antibiotics that emerged were mainly directed to Gram-positive bacteria. Thus, we are now facing to multidrug-resistant Gram-negative bacteria, with no therapeutic options to deal with them. These bacteria are mainly resistant because of their double membrane that conjointly impairs antibiotic accumulation and extrudes these molecules when entered. The main challenge is to allow antibiotics to cross the impermeable envelope and reach their targets. One promising solution would be to associate, in a combination therapy, a usual antibiotic with a non-antibiotic chemosensitizer. Nevertheless, for effective drug discovery, there is a prominent lack of tools required to understand the rules of permeation and accumulation into Gram-negative bacteria. By the use of a multidrug-resistant enterobacteria, we introduce a high-content screening procedure for chemosensitizers discovery by quantitative assessment of drug accumulation, alteration of barriers, and deduction of their activity profile. We assembled and analyzed a control chemicals library to perform the proof of concept. The analysis was based on real-time monitoring of the efflux alteration and measure of the influx increase in the presence of studied compounds in an automatized bio-assay. Then, synergistic activity of compounds with an antibiotic was studied and kinetic data reduction was performed which led to the calculation of a score for each barrier to be altered.

Electron transport chains of lactic acid bacteria

NARCIS (Netherlands)

Brooijmans, R.J.W.

2008-01-01

Lactic acid bacteria are generally considered facultative anaerobic obligate fermentative bacteria. They are unable to synthesize heme. Some lactic acid bacteria are unable to form menaquinone as well. Both these components are cofactors of respiratory (electron transport) chains of prokaryotic

Aging in bacteria, immortality or not-a critical review.

Science.gov (United States)

Gómez, José M G

2010-12-01

Bacteria were traditionally thought to have a symmetrical binary fission without a clear distinction between soma and germ-line, being thus considered as immortal biological entities. Yet it has been recently described that bacteria also undergo replicative aging (RA). That is, they exhibit finite replicative abilities under good conditions to growth. The apparently initial indistinguishability of sibling cells after cytokinesis is broken. After division, the daughter cell that inherits the "old" pole present in the "mother cell" progressively exhibits a decline in its proliferative capacity with increasing cell pole age. This is a clear hallmark and phenotypic manifestation of a bona fide RA phenomenon in toto. While the exact molecular mechanism(s) underlying to this lost of replicative potential are not yet fully understood, the "old pole cell" is considered as an aging parent that in a repeatedly manner is able to produce rejuvenated offspring which inherit a resetting of the biological clock. On the order hand, bacteria exhibit in addition to this "mandatory" RA the dubbed conditional senescence (CS). CS is defined as a decline in cellular viability observed in arrested-growing bacteria populations, a phenomenon apparently not related to RA under growing active conditions. To understand bacterial aging, it is necessary to put it within the sociality-multicellularity framework. This is a new conceptual paradigm that expresses the natural reality of the bacterial world. From this more ecological perspective these bacterial aging phenomena probably should represent an insurance/bethedging anticipative survival strategy. This is underpinned in a self-generation of an appropriate level of populational phenotypic diversity. That is, bacterial aging could be considered a communitarian adaptive response to cope with different environmental stresses and threats. I have highlighted the necessity to construct an integrative conceptual framework to achieve a unified view

Antimicrobial resistance genes in marine bacteria and human uropathogenic Escherichia coli from a region of intensive aquaculture.

Science.gov (United States)

Tomova, Alexandra; Ivanova, Larisa; Buschmann, Alejandro H; Rioseco, Maria Luisa; Kalsi, Rajinder K; Godfrey, Henry P; Cabello, Felipe C

2015-10-01

Antimicrobials are heavily used in Chilean salmon aquaculture. We previously found significant differences in antimicrobial-resistant bacteria between sediments from an aquaculture and a non-aquaculture site. We now show that levels of antimicrobial resistance genes (ARG) are significantly higher in antimicrobial-selected marine bacteria than in unselected bacteria from these sites. While ARG in tetracycline- and florfenicol-selected bacteria from aquaculture and non-aquaculture sites were equally frequent, there were significantly more plasmid-mediated quinolone resistance genes per bacterium and significantly higher numbers of qnrB genes in quinolone-selected bacteria from the aquaculture site. Quinolone-resistant urinary Escherichia coli from patients in the Chilean aquacultural region were significantly enriched for qnrB (including a novel qnrB gene), qnrS, qnrA and aac(6')-1b, compared with isolates from New York City. Sequences of qnrA1, qnrB1 and qnrS1 in quinolone-resistant Chilean E. coli and Chilean marine bacteria were identical, suggesting horizontal gene transfer between antimicrobial-resistant marine bacteria and human pathogens. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

When it comes to antibiotics, bacteria show some NO-how.

Science.gov (United States)

Patel, Bhumit A; Crane, Brian R

2010-10-01

Homologs to mammalian nitric oxide synthases are found in many mostly Gram-positive bacteria. In some genera such as bacilli, and staphylococci, these enzymes produce protects against oxidative damage, this effect has now been shown to provide an advantage against antibiotics that kill by increasing cellular levels of reactive oxygen species.

Effect of Combined Application of Phosphate Solubilizing Bacteria and Phosphrous Fertilizer on Growth and Yield of Sesame

Directory of Open Access Journals (Sweden)

S. Nikmehr

2016-02-01

Full Text Available Introduction: Phosphorus (P is considered to be one of the most essential macro elements required for growth and development of plants, but, due to low solubility and fixation in soils, only a small fraction of phosphorus in soil (1 ppm or 0.1% is readily available to plants. chemical fertilizers are widely used in meeting the phosphorous need of crops. However, as the fertilizer production is dependent upon fossil energy sources, continuous use of chemical fertilizers has become a matter of great concern, not only because of the diminishing availability of costly inputs but environmental concerns also. Under this background, it has obviously brought the subject of mineral phosphate solubilization in the forefront. A group of soil microorganisms is recognized to be involved in microbial phosphate solubilization mechanisms through which insoluble forms of inorganic and organic phosphates convert into soluble forms (HPO4-2 or H2PO4-. Acidification of the medium, chelating, exchange reactions and production of various acids has been discussed as the key processes attributed to the conversion. Phosphate solubilizing bacteria (PSB are a group of plant growth promoting rhizobacteria (PGPR that convert unavailable forms of phosphorus to available forms and it helps to the growth and yield of plant. The use of plant growth promoting rhizobacteria (PGPR is considered one of the most important factors increasing sesame yields. Therefore, the aim of the present study was to investigate the interactive effects of PGPR and phosphorus fertilizer on some growth parameters and components of yield and also phosphorus and Zinc uptake in sesame. Materials and Methods: In order to investigation of the effect of combined application of phosphate solubilizing bacteria and phosphorus fertilizer on growth and yield of Sesame, a greenhouse experiment was conducted as factorial based on completely randomized design with three replications including five levels of

Lactic acid bacteria in dairy food: surface characterization and interactions with food matrix components.

Science.gov (United States)

Burgain, J; Scher, J; Francius, G; Borges, F; Corgneau, M; Revol-Junelles, A M; Cailliez-Grimal, C; Gaiani, C

2014-11-01

This review gives an overview of the importance of interactions occurring in dairy matrices between Lactic Acid Bacteria and milk components. Dairy products are important sources of biological active compounds of particular relevance to human health. These compounds include immunoglobulins, whey proteins and peptides, polar lipids, and lactic acid bacteria including probiotics. A better understanding of interactions between bioactive components and their delivery matrix may successfully improve their transport to their target site of action. Pioneering research on probiotic lactic acid bacteria has mainly focused on their host effects. However, very little is known about their interaction with dairy ingredients. Such knowledge could contribute to designing new and more efficient dairy food, and to better understand relationships between milk constituents. The purpose of this review is first to provide an overview of the current knowledge about the biomolecules produced on bacterial surface and the composition of the dairy matter. In order to understand how bacteria interact with dairy molecules, adhesion mechanisms are subsequently reviewed with a special focus on the environmental conditions affecting bacterial adhesion. Methods dedicated to investigate the bacterial surface and to decipher interactions between bacteria and abiotic dairy components are also detailed. Finally, relevant industrial implications of these interactions are presented and discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

Design of safeguards information treatment system at the facility level

Energy Technology Data Exchange (ETDEWEB)

Song, Dae Yong; Lee, Byung Doo; Kwack, Eun Ho; Choi, Young Myong

2001-05-01

We are developing Safeguards Information Treatment System at the facility level(SITS) to manage synthetically safeguards information and to implement efficiently the obligations under the Korea-IAEA Safeguards Agreement, bilateral agreements with other countries and domestic law. In this report, we described the contents of the detailed design of SITS such as database, I/O layout and program. In the present, we are implementing the SITS based on the contents of the design of SITS, and then we plan to provide the system for the facilities after we finish implementing and testing the system.

Design of safeguards information treatment system at the facility level

International Nuclear Information System (INIS)

Song, Dae Yong; Lee, Byung Doo; Kwack, Eun Ho; Choi, Young Myong

2001-05-01

We are developing Safeguards Information Treatment System at the facility level(SITS) to manage synthetically safeguards information and to implement efficiently the obligations under the Korea-IAEA Safeguards Agreement, bilateral agreements with other countries and domestic law. In this report, we described the contents of the detailed design of SITS such as database, I/O layout and program. In the present, we are implementing the SITS based on the contents of the design of SITS, and then we plan to provide the system for the facilities after we finish implementing and testing the system

Antibacterial Activities of Endophytic Bacteria Isolated from Taxus brevifolia Against Foodborne Pathogenic Bacteria.

Science.gov (United States)

Islam, Nurul; Choi, Jaehyuk; Baek, Kwang-Hyun

2018-05-01

Endophytes are a potential source of novel bioactive compounds with medicinal properties. In this study, 41 endophytic bacteria (EB) were isolated from tissues of a medicinally important plant Taxus brevifolia (Pacific yew). The objective was to screen all the EB isolates for their antibacterial effects against five foodborne pathogenic bacteria: Bacillus cereus ATCC10876, Staphylococcus aureus ATCC12600, Listeria monocytogenes ATCC19115, Escherichia coli ATCC43890, and Salmonella Typhimurium ATCC19585. Among the EB isolates, T. brevifolia seed (TbS)-8, T. brevifolia fleshy part of fruit (TbFl)-10, T. brevifolia leaf (TbL)-22, TbS-29, and TbL-34 exerted significant antibacterial activity against the tested foodborne pathogens. Especially TbFl-10 showed the highest antibacterial activity against all the tested bacteria and was identified as Paenibacillus kribbensis (Pk). Furthermore, an ethyl acetate extract of Pk-TbFl-10 possessed antibacterial activities against the tested five foodborne pathogenic bacteria, with zones of inhibition from 15.71 ± 2.85 to 13.01 ± 2.12 mm. Scanning electron microscopy analysis revealed ruptured, lysed, shrunk, and swollen cells of all the tested foodborne pathogens treated with the ethyl acetate extract of Pk-TbFl-10, suggesting that a metabolite(s) of Pk-TbFl-10 penetrates the cell membrane and causes cell lysis leading to cell death. Our results indicate that Pk-TbFl-10 isolated from T. brevifolia can serve as a novel source of natural antibacterial agents against foodborne pathogenic bacteria, with potential applications in the pharmaceutical industry.

Biochemistry, physiology and biotechnology of sulfate-reducing bacteria.

Science.gov (United States)

Barton, Larry L; Fauque, Guy D

2009-01-01

Chemolithotrophic bacteria that use sulfate as terminal electron acceptor (sulfate-reducing bacteria) constitute a unique physiological group of microorganisms that couple anaerobic electron transport to ATP synthesis. These bacteria (220 species of 60 genera) can use a large variety of compounds as electron donors and to mediate electron flow they have a vast array of proteins with redox active metal groups. This chapter deals with the distribution in the environment and the major physiological and metabolic characteristics of sulfate-reducing bacteria (SRB). This chapter presents our current knowledge of soluble electron transfer proteins and transmembrane redox complexes that are playing an essential role in the dissimilatory sulfate reduction pathway of SRB of the genus Desulfovibrio. Environmentally important activities displayed by SRB are a consequence of the unique electron transport components or the production of high levels of H(2)S. The capability of SRB to utilize hydrocarbons in pure cultures and consortia has resulted in using these bacteria for bioremediation of BTEX (benzene, toluene, ethylbenzene and xylene) compounds in contaminated soils. Specific strains of SRB are capable of reducing 3-chlorobenzoate, chloroethenes, or nitroaromatic compounds and this has resulted in proposals to use SRB for bioremediation of environments containing trinitrotoluene and polychloroethenes. Since SRB have displayed dissimilatory reduction of U(VI) and Cr(VI), several biotechnology procedures have been proposed for using SRB in bioremediation of toxic metals. Additional non-specific metal reductase activity has resulted in using SRB for recovery of precious metals (e.g. platinum, palladium and gold) from waste streams. Since bacterially produced sulfide contributes to the souring of oil fields, corrosion of concrete, and discoloration of stonework is a serious problem, there is considerable interest in controlling the sulfidogenic activity of the SRB. The

Money and transmission of bacteria.

NARCIS (Netherlands)

Gedik, H.; Voss, T.A.; Voss, A.

2013-01-01

Money is one of the most frequently passed items in the world. The aim of this study was to ascertain the survival status of bacteria including Staphylococcus aureus, Escherichia coli, and Vancomycin- Resistant Enterococci (VRE) on banknotes from different countries and the transmission of bacteria

Review of optimization strategies for system-level design in hybrid electric vehicles

NARCIS (Netherlands)

Silvas, E.; Hofman, T.; Murgovski, N.; Etman, P.; Steinbuch, M.

2017-01-01

The optimal design of a hybrid electric vehicle can be formulated as a multi-objective optimization problem that spreads over multiple levels (technology, topology, size and control). In the last decade, studies have shown that, by integrating these optimization levels fuel benefits are obtained,

Seismic design ampersand analysis considerations for high level nuclear waste repositories

International Nuclear Information System (INIS)

Hossain, Q.A.

1993-01-01

A high level nuclear waste repository, like the one at Nevada's Yucca Mountain that is being investigated for site suitability, will have some unique seismic design and analysis considerations. These are discussed, and a design philosophy that can rationally account for the unique performance objectives of such facilities is presented. A case is made for the use of DOE's performance goal-based seismic design and evaluation methodology that is based on a hybrid open-quotes deterministicclose quotes and open-quotes probabilisticclose quotes concept. How and to what extent this methodology should be modified to adopt it for a potential site like Yucca Mountain is also outlined. Finally, the issue of designing for seismic fault rupture is discussed briefly, and the desirability of using the proposed seismic design philosophy in fault rupture evaluation is described

Seismic design and analysis considerations for high level nuclear waste repositories

International Nuclear Information System (INIS)

Hossain, Q.A.

1993-01-01

A high level nuclear waste repository, like the one at Nevada's Yucca Mountain that is being investigated for site suitability, will have some unique seismic design and analysis considerations. These are discussed, and a design philosophy that can rationally account for the unique performance objectives of such facilities is presented. A case is made for the use of DOE's performance goal-based seismic design and evaluation methodology that is based on a hybrid ''deterministic'' and ''probabilistic'' concept. How and to what extent this methodology should be modified to adopt it for a potential site like Yucca Mountain is also outlined. Finally, the issue of designing for seismic fault rupture is discussed briefly, and the desirability of using the proposed seismic design philosophy in fault rupture evaluation is described

Review on SERS of Bacteria

Directory of Open Access Journals (Sweden)

Pamela A. Mosier-Boss

2017-11-01

Full Text Available Surface enhanced Raman spectroscopy (SERS has been widely used for chemical detection. Moreover, the inherent richness of the spectral data has made SERS attractive for use in detecting biological materials, including bacteria. This review discusses methods that have been used to obtain SERS spectra of bacteria. The kinds of SERS substrates employed to obtain SERS spectra are discussed as well as how bacteria interact with silver and gold nanoparticles. The roll of capping agents on Ag/Au NPs in obtaining SERS spectra is examined as well as the interpretation of the spectral data.

Using Fluorescent Viruses for Detecting Bacteria in Water

Science.gov (United States)

Tabacco, Mary Beth; Qian, Xiaohua; Russo, Jaimie A.

2009-01-01

A method of detecting water-borne pathogenic bacteria is based partly on established molecular-recognition and fluorescent-labeling concepts, according to which bacteria of a species of interest are labeled with fluorescent reporter molecules and the bacteria can then be detected by fluorescence spectroscopy. The novelty of the present method lies in the use of bacteriophages (viruses that infect bacteria) to deliver the fluorescent reporter molecules to the bacteria of the species of interest.

Cytochrome cd1-containing nitrite reductase encoding gene nirS as a new functional biomarker for detection of anaerobic ammonium oxidizing (Anammox) bacteria.

Science.gov (United States)

Li, Meng; Ford, Tim; Li, Xiaoyan; Gu, Ji-Dong

2011-04-15

A newly designed primer set (AnnirS), together with a previously published primer set (ScnirS), was used to detect anammox bacterial nirS genes from sediments collected from three marine environments. Phylogenetic analysis demonstrated that all retrieved sequences were clearly different from typical denitrifiers' nirS, but do group together with the known anammox bacterial nirS. Sequences targeted by ScnirS are closely related to Scalindua nirS genes recovered from the Peruvian oxygen minimum zone (OMZ), whereas sequences targeted by AnnirS are more closely affiliated with the nirS of Candidatus 'Kuenenia stuttgartiensis' and even form a new phylogenetic nirS clade, which might be related to other genera of the anammox bacteria. Analysis demonstrated that retrieved sequences had higher sequence identities (>60%) with known anammox bacterial nirS genes than with denitrifiers' nirS, on both nucleotide and amino acid levels. Compared to the 16S rRNA and hydrazine oxidoreductase (hzo) genes, the anammox bacterial nirS not only showed consistent phylogenetic relationships but also demonstrated more reliable quantification of anammox bacteria because of the single copy of the nirS gene in the anammox bacterial genome and the specificity of PCR primers for different genera of anammox bacteria, thus providing a suitable functional biomarker for investigation of anammox bacteria.

Characterization of DNA-repair potential in deep subsurface bacteria challenged by UV light, hydrogen peroxide, and gamma radiation

OpenAIRE

Arrage, Andrew Anthony

1991-01-01

Subsurface bacterial isolates obtained through the DOE Subsurface Science Program were tested for resistance to UV light, gamma radiation and H202. Some deep subsurface bacteria were resistant to UV light, demonstrating â ¥1.0% survival at fluences which resulted in a 0.0001% survival level of E. coli B. The percentage of UV resistant aerobic subsurface bacteria and surface soil bacteria were similar; 30.8% and 25.8% respectively. All of the microaerophilic subsurface isolates ...

Screening and biological characteristics of fufenozide degrading bacteria

Science.gov (United States)

Xu, Chenhao; Gong, Mingfu; Guan, Qinlan; Deng, Xia; Deng, Hongyan; Huang, Jiao

2018-04-01

Fufenozide was a novel pesticide for the control of Lepidoptera pests, which was highly toxic to silkworm. Fufenozide-contaminated soil samples were collected and the bacteria that degrade fufenozide were isolated and screened by selective medium. The colony characteristics, cell characteristics and degradation characteristics in different concentrations fufenozide of the fufenozide degrading bacteria were studied. The results indicated that seven strains of fufenozide degradeing bacteria, named as DDH01, DDH03, DDH04, DDH04, DDH05, DDH07 and DDH07 respectively, were isolated from soil contaminated with fufenozide. DDH01, DDH02, DDH04 and DDH05 of seven fufenozide degrading bacteria, was gram-positive bacteria, and DDH03, DDH06 and DDH07 was gram-negative bacteria. All of seven strains of fufenozide degrading bacteria were not spores, weeks flagella, rod-shaped bacteria. DDH06 and DDH07 had capsules, and the remaining five strains had not capsule. The colonies formed by seven strains of fufenozide degradation bacteria on beef extract peptone medium plate were milky white colonies with irregular edges, thinner lawn, smaller colony with smooth surface. The growth of 7 strains of fufenozide degradation bacteria was significantly affected by the concentration of fufenozide, All of 7 strains grown in the range from 0.00025 g/mL to 1 g/mL of 10% fufenozide suspension. DDH2 was the best among the 7 strains of fufenozide degrading bacteria grown in 10% fufenozide suspension medium.

HYDROCARBON-DEGRADING BACTERIA AND SURFACTANT ACTIVITY

Energy Technology Data Exchange (ETDEWEB)

Brigmon, R; Topher Berry, T; Grazyna A. Plaza, G; jacek Wypych, j

2006-08-15

Fate of benzene ethylbenzene toluene xylenes (BTEX) compounds through biodegradation was investigated using two different bacteria, Ralstonia picketti (BP-20) and Alcaligenes piechaudii (CZOR L-1B). These bacteria were isolated from extremely polluted petroleum hydrocarbon contaminated soils. PCR and Fatty Acid Methyl Ester (FAME) were used to identify the isolates. Biodegradation was measured using each organism individually and in combination. Both bacteria were shown to degrade each of the BTEX compounds. Alcaligenes piechaudii biodegraded BTEXs more efficiently while mixed with BP-20 and individually. Biosurfactant production was observed by culture techniques. In addition 3-hydroxy fatty acids, important in biosurfactant production, was observed by FAME analysis. In the all experiments toluene and m+p- xylenes were better growth substrates for both bacteria than the other BTEX compounds. In addition, the test results indicate that the bacteria could contribute to bioremediation of aromatic hydrocarbons (BTEX) pollution increase biodegradation through the action by biosurfactants.

Labelled Thioamino Acids to Indicate the Synthetic Activity of the Rumen Bacteria in In-Vitro Experiments

Energy Technology Data Exchange (ETDEWEB)

Panic, B.; Jovanovic, M.; Cuperlovic, M.; Djordjevic, D. [Institute for the Application of Nuclear Energy in Agriculture, Veterinary Medicine and Forestry, Belgrade, Yugoslavia (Serbia)

1968-07-01

The synthetic activity of rumen bacteria has been studied in vitro through the investigation of cystine and methionine concentration and their specific activity. {sup 35}S-sulphate has been used as a radioactive tracer. Two diets, different in the level of nutrients - energy and protein - were added to the artificial tumen. The incubation with bacteria from the rumen content of the cows, fed for four weeks with the same diet, lasted 19 h. The diet with the higher level of protein and energy increased the cystine content (per 100 mg of N{sub 2}) by 23.3% and the methionine content by 39.4%. The concentration of radioactive cystine was increased at the same percentage rate by 25%, but radioactive methionine was much lower and increased only 6.4%. The difference between the specific activities of the investigated amino acids can be explained by the different catabolism rate and utilization of dietary cystine, and methionine by the rumen bacterial flora. Since the dietary methionine is catabolized slowly, it can, especially by the use of the diets with a high protein level, significantly decrease the specific activity of the radioactive methionine synthesized by rumen bacteria. Therefore, the incorporation of {sup 35}S into the cystine represents a more reliable indicator of the synthetic activity of the rumen bacteria. (author)

Antifungal Bacteria on Woodland Salamander Skin Exhibit High Taxonomic Diversity and Geographic Variability.

Science.gov (United States)

Muletz-Wolz, Carly R; DiRenzo, Graziella V; Yarwood, Stephanie A; Campbell Grant, Evan H; Fleischer, Robert C; Lips, Karen R

2017-05-01

Diverse bacteria inhabit amphibian skin; some of those bacteria inhibit growth of the fungal pathogen Batrachochytrium dendrobatidis Yet there has been no systematic survey of anti- B. dendrobatidis bacteria across localities, species, and elevations. This is important given geographic and taxonomic variations in amphibian susceptibility to B. dendrobatidis Our collection sites were at locations within the Appalachian Mountains where previous sampling had indicated low B. dendrobatidis prevalence. We determined the numbers and identities of anti- B. dendrobatidis bacteria on 61 Plethodon salamanders (37 P. cinereus , 15 P. glutinosus , 9 P. cylindraceus ) via culturing methods and 16S rRNA gene sequencing. We sampled co-occurring species at three localities and sampled P. cinereus along an elevational gradient (700 to 1,000 meters above sea level [masl]) at one locality. We identified 50 anti- B. dendrobatidis bacterial operational taxonomic units (OTUs) and found that the degree of B. dendrobatidis inhibition was not correlated with relatedness. Five anti- B. dendrobatidis bacterial strains occurred on multiple amphibian species at multiple localities, but none were shared among all species and localities. The prevalence of anti- B. dendrobatidis bacteria was higher at Shenandoah National Park (NP), VA, with 96% (25/26) of salamanders hosting at least one anti- B. dendrobatidis bacterial species compared to 50% (7/14) at Catoctin Mountain Park (MP), MD, and 38% (8/21) at Mt. Rogers National Recreation Area (NRA), VA. At the individual level, salamanders at Shenandoah NP had more anti- B. dendrobatidis bacteria per individual (μ = 3.3) than those at Catoctin MP (μ = 0.8) and at Mt. Rogers NRA (μ = 0.4). All salamanders tested negative for B. dendrobatidis Anti- B. dendrobatidis bacterial species are diverse in central Appalachian Plethodon salamanders, and their distribution varied geographically. The antifungal bacterial species that we identified may play a

Acetic acid bacteria: A group of bacteria with versatile biotechnological applications.

Science.gov (United States)

Saichana, Natsaran; Matsushita, Kazunobu; Adachi, Osao; Frébort, Ivo; Frebortova, Jitka

2015-11-01

Acetic acid bacteria are gram-negative obligate aerobic bacteria assigned to the family Acetobacteraceae of Alphaproteobacteria. They are members of the genera Acetobacter, Gluconobacter, Gluconacetobacter, Acidomonas, Asaia, Kozakia, Swaminathania, Saccharibacter, Neoasaia, Granulibacter, Tanticharoenia, Ameyamaea, Neokomagataea, and Komagataeibacter. Many strains of Acetobacter and Komagataeibacter have been known to possess high acetic acid fermentation ability as well as the acetic acid and ethanol resistance, which are considered to be useful features for industrial production of acetic acid and vinegar, the commercial product. On the other hand, Gluconobacter strains have the ability to perform oxidative fermentation of various sugars, sugar alcohols, and sugar acids leading to the formation of several valuable products. Thermotolerant strains of acetic acid bacteria were isolated in order to serve as the new strains of choice for industrial fermentations, in which the cooling costs for maintaining optimum growth and production temperature in the fermentation vessels could be significantly reduced. Genetic modifications by adaptation and genetic engineering were also applied to improve their properties, such as productivity and heat resistance. Copyright © 2014 Elsevier Inc. All rights reserved.

Interactions between stream fungi and bacteria associated with decomposing leaf litter at different levels of nutrient availability

Science.gov (United States)

Vladislav Gulis; Keller Suberkropp

2003-01-01

We examined the potential for interactions between aquatic hyphomycetes and bacteria isolated from leaves decaying in a headwater stream. In agar plate assays, culture filtrates of each of 28 aquatic hyphomycete isolates tested (5 species) inhibited bacterial growth (16 Gram-negative bacterial isolates belonging to 6 colony morphotypes were tested). Inhibition of...

Sheep manure vermicompost supplemented with a native diazotrophic bacteria and mycorrhizas for maize cultivation.

Science.gov (United States)

Gutiérrez-Miceli, F A; Moguel-Zamudio, B; Abud-Archila, M; Gutiérrez-Oliva, V F; Dendooven, L

2008-10-01

An orthogonal experimental design L9 (3(4)) with 10 repetitions was used to investigate the effect of Glomus claroideum (0, 1 or 2g(-1) plant), G. fasciculatum (0, 1 or 2g plant(-1)), native diazotrophic bacteria (0, 10(3) and 10(5) UFC ml(-1)) and sheep manure vermicompost (0%, 5% and 10% v/v) on maize plant growth, N and P in leaves and mycorrhization percent. Vermicompost explained most of the variation found for leaf number, wet weight, stem height, and diameter. Both mycorrhizas increased the plant wet weight but G. fasciculatum the most. Mycorrhization increased the P content, but not the N content. Mycorrhizal colonization increased when diazotrophic bacteria and vermicompost were added. It was found that weight of maize plants cultivated in peat moss amended with vermicompost increased when supplemented with G. fasciculatum and diazotrophic bacteria.

Programmable System-on-Chip (PSoC) Embedded Readout Designs for Liquid Helium Level Sensors.

Science.gov (United States)

Parasakthi, C; Gireesan, K; Usha Rani, R; Sheela, O K; Janawadkar, M P

2014-08-01

This article reports the development of programmable system-on-chip (PSoC)-based embedded readout designs for liquid helium level sensors using resistive liquid vapor discriminators. The system has been built for the measurement of liquid helium level in a concave-bottomed, helmet-shaped, fiber-reinforced plastic cryostat for magnetoencephalography. This design incorporates three carbon resistors as cost-effective sensors, which are mounted at desired heights inside the cryostat and were used to infer the liquid helium level by measuring their temperature-dependent resistance. Localized electrical heating of the carbon resistors was used to discriminate whether the resistor is immersed in liquid helium or its vapor by exploiting the difference in the heat transfer rates in the two environments. This report describes a single PSoC chip for the design and development of a constant current source to drive the three carbon resistors, a multiplexer to route the sensor outputs to the analog-to-digital converter (ADC), a buffer to avoid loading of the sensors, an ADC for digitizing the data, and a display using liquid crystal display cum light-emitting diode modules. The level sensor readout designed with a single PSoC chip enables cost-effective and reliable measurement system design. © 2014 Society for Laboratory Automation and Screening.

High-voltage Pulse-triggered SR Latch Level-Shifter Design Considerations

DEFF Research Database (Denmark)

Larsen, Dennis Øland; Llimos Muntal, Pere; Jørgensen, Ivan Harald Holger

2014-01-01

translating a signal from 0- 3 : 3 V to 87 : 5 - 100 V. The operation of this level-shifter is verified with measurements on a fabricated chip. The shortcomings of the implemented level-shifter in terms of power dissipation, transition delay, area, and startup behavior are then considered and an improved......This paper compares pulse-triggered level shifters with a traditional level-triggered topology for high-voltage ap- plications with supply voltages in the 50 V to 100 V range. It is found that the pulse-triggered SR (Set/Reset) latch level- shifter has a superior power consumption of 1800 W = MHz...... circuit is suggested which has been designed in three variants being able to translate the low-voltage 0- 3 : 3 V signal to 45 - 50 V, 85 - 90 V, and 95 - 100 V respectively. The improved 95 - 100 V level shifter achieves a considerably lower power consumption of 438 W = MHz along with a significantly...

Forest Soil Bacteria: Diversity, Involvement in Ecosystem Processes, and Response to Global Change.

Science.gov (United States)

Lladó, Salvador; López-Mondéjar, Rubén; Baldrian, Petr

2017-06-01

The ecology of forest soils is an important field of research due to the role of forests as carbon sinks. Consequently, a significant amount of information has been accumulated concerning their ecology, especially for temperate and boreal forests. Although most studies have focused on fungi, forest soil bacteria also play important roles in this environment. In forest soils, bacteria inhabit multiple habitats with specific properties, including bulk soil, rhizosphere, litter, and deadwood habitats, where their communities are shaped by nutrient availability and biotic interactions. Bacteria contribute to a range of essential soil processes involved in the cycling of carbon, nitrogen, and phosphorus. They take part in the decomposition of dead plant biomass and are highly important for the decomposition of dead fungal mycelia. In rhizospheres of forest trees, bacteria interact with plant roots and mycorrhizal fungi as commensalists or mycorrhiza helpers. Bacteria also mediate multiple critical steps in the nitrogen cycle, including N fixation. Bacterial communities in forest soils respond to the effects of global change, such as climate warming, increased levels of carbon dioxide, or anthropogenic nitrogen deposition. This response, however, often reflects the specificities of each studied forest ecosystem, and it is still impossible to fully incorporate bacteria into predictive models. The understanding of bacterial ecology in forest soils has advanced dramatically in recent years, but it is still incomplete. The exact extent of the contribution of bacteria to forest ecosystem processes will be recognized only in the future, when the activities of all soil community members are studied simultaneously. Copyright © 2017 American Society for Microbiology.

Exploiting pH-Regulated Dimer-Tetramer Transformation of Concanavalin A to Develop Colorimetric Biosensing of Bacteria.

Science.gov (United States)

Xu, Xiahong; Yuan, Yuwei; Hu, Guixian; Wang, Xiangyun; Qi, Peipei; Wang, Zhiwei; Wang, Qiang; Wang, Xinquan; Fu, Yingchun; Li, Yanbin; Yang, Hua

2017-05-03

Gold nanoparticles (AuNPs) aggregation-based colorimetric biosensing remains a challenge for bacteria due to their large size. Here we propose a novel colorimetric biosensor for rapid detection of Escherichia coli O157:H7 (E. coli O157:H7) in milk samples based on pH-regulated transformation of dimer/tetramer of Concanavalin A (Con A) and the Con A-glycosyl recognition. Briefly, antibody-modified magnetic nanoparticles was used to capture and concentrate E. coli O157:H7 and then to label with Con A; pH adjusted to 5 was then applied to dissociate Con A tetramer to release dimer, which was collected and re-formed tetramer at pH of 7 to cause the aggregation of dextran-modified AuNPs. The interesting pH-dependent conformation-transformation behavior of Con A innovated the design of the release from the bacteria surface and then the reconstruction of Con A. Therefore, we realized the sensitive colorimetric biosensing of bacteria, which are much larger than AuNPs that is generally not suitable for this kind of method. The proposed biosensor exhibited a limit of detection down to 41 CFU/mL, short assay time (~95 min) and satisfactory specificity. The biosensor also worked well for the detection in milk sample, and may provide a universal concept for the design of colorimetric biosensors for bacteria and virus.

Toxicity Evaluation of Pig Slurry Using Luminescent Bacteria and Zebrafish

Directory of Open Access Journals (Sweden)

Wenyan Chen

2014-07-01

Full Text Available Biogas slurry has become a serious pollution problem and anaerobic digestion is widely applied to pig manure treatment for environmental protection and energy recovery. To evaluate environmental risk of the emission of biogas slurry, luminescent bacteria (Vibrio fischeri, larvae and embryos of zebrafish (Danio rerio were used to detect the acute and development toxicity of digested and post-treated slurry. Then the ability of treatment process was evaluated. The results showed that digested slurry displayed strong toxicity to both zebrafish and luminescent bacteria, while the EC50 for luminescent bacteria and the LC50 for larvae were only 6.81% (v/v and 1.95% (v/v respectively, and embryonic development was inhibited at just 1% (v/v. Slurry still maintained a high level of toxicity although it had been treated by membrane bioreactor (MBR, while the LC50 of larvae was 75.23% (v/v and there was a little effect on the development of embryos and V. fischeri; the results also revealed that the zebrafish larvae are more sensitive than embryos and luminescent bacteria to pig slurry. Finally, we also found the toxicity removal rate was higher than 90% after the treatment of MBR according to toxicity tests. In conclusion, further treatment should be used in pig slurry disposal or reused of final effluent.

Incidence of plant cover over the autotrophic nitrifying bacteria population in a fragment of Andean forest

International Nuclear Information System (INIS)

Gonzalez, Xiomara; Gonzalez, L; Varela, A; Ahumada, J A

1999-01-01

It was determined the incidence of plant cover (forest vs. pasture), on the autotrophy nitrifying bacteria, through the effect of biotic factors (radical exudate) and abiotic factors (temperature, ph and humidity), in a high mountain cloud forest fragment. The site of study was located near La Mesa (Cundinamarca) municipality. The temperature of soil was measured in situ, and soil samples were collected and carried to the laboratory for pH and humidity percentage measurements. Serial soil dilution method was used for plating samples on a selective culture medium with ammonium sulphate as nitrogen source, in order to estimate the autotrophic nitrifying bacteria population levels. Grown colonies were examined macro and microscopically. The quantity of nitrates produced by bacteria cultured in vitro was determined spectra-photometrical. In relation to the abiotic factors, there was no significant differences of pH between both plant covers, but there were significant for soil humidity and temperature (p<0.05). There were highly significant differences with respect to the bacteria population levels (p<0.0001) and with respect to nitrate production. This suggests a higher bacterial activity in the under forest cover. The radical exudate from both types of plant cover reduced the viability of bacteria in vitro, from 1:1 to 1:30 exudate bacteria proportions. In the soils physical and chemical analysis, it was found a higher P and Al concentrations, and a higher CIC and organic matter content under the forest cover. It is suggested the importance of this functional group in this ecosystem

Bacteria-mediated bisphenol A degradation.

Science.gov (United States)

Zhang, Weiwei; Yin, Kun; Chen, Lingxin

2013-07-01

Bisphenol A (BPA) is an important monomer in the manufacture of polycarbonate plastics, food cans, and other daily used chemicals. Daily and worldwide usage of BPA and BPA-contained products led to its ubiquitous distribution in water, sediment/soil, and atmosphere. Moreover, BPA has been identified as an environmental endocrine disruptor for its estrogenic and genotoxic activity. Thus, BPA contamination in the environment is an increasingly worldwide concern, and methods to efficiently remove BPA from the environment are urgently recommended. Although many factors affect the fate of BPA in the environment, BPA degradation is mainly depended on the metabolism of bacteria. Many BPA-degrading bacteria have been identified from water, sediment/soil, and wastewater treatment plants. Metabolic pathways of BPA degradation in specific bacterial strains were proposed, based on the metabolic intermediates detected during the degradation process. In this review, the BPA-degrading bacteria were summarized, and the (proposed) BPA degradation pathway mediated by bacteria were referred.

The antibiotic resistome of free-living and particle-attached bacteria under a reservoir cyanobacterial bloom.

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Guo, Yunyan; Liu, Min; Liu, Lemian; Liu, Xuan; Chen, Huihuang; Yang, Jun

2018-05-04

In freshwater systems, both antibiotic resistance genes (ARGs) and cyanobacterial blooms attract global public health concern. Cyanobacterial blooms can greatly impact bacterial taxonomic communities, but very little is known about the influence of the blooms on antibiotic resistance functional community. In this study, the ARGs in both free-living (FL) and particle-attached (PA) bacteria under bloom and non-bloom conditions were simultaneously investigated in a subtropical reservoir using high-throughput approaches. In total, 145 ARGs and 9 mobile genetic elements (MGEs) were detected. The most diverse and dominant of which (68.93%) were multidrug resistance genes and efflux pump mechanism. The richness of ARGs in both FL and PA bacteria was significantly lower during the bloom period compared with non-bloom period. The abundance of ARGs in FL bacteria was significantly lower under bloom condition than in the non-bloom period, but the abundance of ARGs in PA bacteria stayed constant. More importantly, the resistant functional community in PA bacteria was more strongly influenced by the cyanobacterial bloom than in the FL bacteria, although >96% ARGs were shared in both FL and PA bacteria or both bloom and non-bloom periods. We also compared the community compositions between taxonomy and function, and found antibiotic resistant communities were highly variable and exhibited lower similarity between bloom and non-bloom periods than seen in the taxonomic composition, with an exception of FL bacteria. Altogether, cyanobacterial blooms appear to have stronger inhibitory effect on ARG abundance in FL bacteria, and stronger influence on antibiotic resistant community composition in PA bacteria. Our results further suggested that both neutral and selective processes interactively affected the ARG composition dynamics of the FL and PA bacteria. However, the antibiotic resistant community of FL bacteria exhibited a higher level of temporal stochasticity following the bloom

COMPARISON THE NUMBER OF BACTERIA BETWEEN WASHING HANDS USING SOAP AND HAND SANITIZER AS A BACTERIOLOGY LEARNING RESOURCE FOR STUDENTS

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Satya Darmayani

2017-11-01

Full Text Available Hands are the principal carriers of bacterial diseases, therefore very important to know that washing hands with soap or hand sanitizer is highly effective healthy behaviors to reduce bacteria in the palm. This study aimed to determine the total number of bacteria between washing hands with soap and hand sanitizer, also applying the results of these studies as a learning resource in bacteriology. The research design was the true experiment with pretest-posttest control group research design and laboratory examination. Analysis of data using paired t-test and independent sample t-test with α = 0.05. The result using paired t-test obtained t count= 2.48921> t 0.05 (14 = 2.14479 (with liquid soap, obtained t count= 2.32937> t 0.05 (14 = 2.14479 (with hand sanitizer. As for the comparison of the total number of bacteria include washing hands with soap and hand sanitizer using independent samples t-test obtained results there were differences in the total number of bacteria include washing hands with liquid soap and hand sanitizer with t count= 2.23755> t 0.05 ( 13 = 2.16037. That results showed hand sanitizer more effective to reduce the number of bacteria than the liquid soap, that was hand sanitizer 96% and liquid soap by 95%.

Classification of plant associated bacteria using RIF, a computationally derived DNA marker.

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Kevin L Schneider

Full Text Available A DNA marker that distinguishes plant associated bacteria at the species level and below was derived by comparing six sequenced genomes of Xanthomonas, a genus that contains many important phytopathogens. This DNA marker comprises a portion of the dnaA replication initiation factor (RIF. Unlike the rRNA genes, dnaA is a single copy gene in the vast majority of sequenced bacterial genomes, and amplification of RIF requires genus-specific primers. In silico analysis revealed that RIF has equal or greater ability to differentiate closely related species of Xanthomonas than the widely used ribosomal intergenic spacer region (ITS. Furthermore, in a set of 263 Xanthomonas, Ralstonia and Clavibacter strains, the RIF marker was directly sequenced in both directions with a success rate approximately 16% higher than that for ITS. RIF frameworks for Xanthomonas, Ralstonia and Clavibacter were constructed using 682 reference strains representing different species, subspecies, pathovars, races, hosts and geographic regions, and contain a total of 109 different RIF sequences. RIF sequences showed subspecific groupings but did not place strains of X. campestris or X. axonopodis into currently named pathovars nor R. solanacearum strains into their respective races, confirming previous conclusions that pathovar and race designations do not necessarily reflect genetic relationships. The RIF marker also was sequenced for 24 reference strains from three genera in the Enterobacteriaceae: Pectobacterium, Pantoea and Dickeya. RIF sequences of 70 previously uncharacterized strains of Ralstonia, Clavibacter, Pectobacterium and Dickeya matched, or were similar to, those of known reference strains, illustrating the utility of the frameworks to classify bacteria below the species level and rapidly match unknown isolates to reference strains. The RIF sequence frameworks are available at the online RIF database, RIFdb, and can be queried for diagnostic purposes with RIF

Structure and activity of lacustrine sediment bacteria involved in nutrient and iron cycles

DEFF Research Database (Denmark)

da Silva Martins, Gilberto Jorge; Terada, Akihiko; Ribeiro, Daniel C

2011-01-01

Knowledge of the bacterial community structure in sediments is essential to better design restoration strategies for eutrophied lakes. In this regard, the aim of this study was to quantify the abundance and activity of bacteria involved in nutrient and iron cycling in sediments from four Azorean...

Evaluation of the Vitek 2 ANC card for identification of clinical isolates of anaerobic bacteria.

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Lee, E H L; Degener, J E; Welling, G W; Veloo, A C M

2011-05-01

An evaluation of the Vitek 2 ANC card (bioMérieux, Marcy l'Etoile, France) was performed with 301 anaerobic isolates. Each strain was identified by 16S rRNA gene sequencing, which is considered to be the reference method. The Vitek 2 ANC card correctly identified 239 (79.4%) of the 301 clinical isolates to the genus level, including 100 species that were not represented in the database. Correct species identification was obtained for 60.1% (181/301) of the clinical isolates. For the isolates not identified to the species level, a correct genus identification was obtained for 47.0% of them (47/100), and 16 were accurately designated not identified. Although the Vitek 2 ANC card allows the rapid and acceptable identification of the most common clinically important anaerobic bacteria within 6 h, improvement is required for the identification of members of the genera Fusobacterium, Prevotella, and Actinomyces and certain Gram-positive anaerobic cocci (GPAC).

Low salinity and high-level UV-B radiation reduce single-cell activity in antarctic sea ice bacteria.

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Martin, Andrew; Hall, Julie; Ryan, Ken

2009-12-01

Experiments simulating the sea ice cycle were conducted by exposing microbes from Antarctic fast ice to saline and irradiance regimens associated with the freeze-thaw process. In contrast to hypersaline conditions (ice formation), the simulated release of bacteria into hyposaline seawater combined with rapid exposure to increased UV-B radiation significantly reduced metabolic activity.

Periodontal status and pathogenic bacteria after gastric bypass: a cohort study.

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Sales-Peres, Sílvia Helena de Carvalho; de Moura-Grec, Patrícia Garcia; Yamashita, Joselene Martinelli; Torres, Elza Araujo; Dionísio, Thiago José; Leite, Celso Vieira de Souza; Sales-Peres, Arsenio; Ceneviva, Reginaldo

2015-06-01

The aim this study was to evaluate the influence of gastric bypass surgery (GBS) on periodontal disease and quantify the periodontopathogenic bacteria in patients undergoing this surgery. This prospective study was composed of 50 patients who underwent bariatric surgery and the data collection was performed in three periods pre-operative, 6 (6M) and 12 months (12 M) postoperative. The oral clinical examination to assess periodontal disease; gingival fluid sample collection for quantification of the periodontopathogenic bacteria Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, and Prevotella intermedia using q-PCR; body mass index (BMI) and for collection of the individual's health-related data from medical files. There was a significant reduction in serum C-reactive protein (CRP) and glucose levels after surgery. The mean probing pocket depth (PPD) and clinical attachment level (CAL) increased significantly in the postoperative period of 6 months (p = 0.001). In the same period, the amount of P. gingivalis increased (p = 0.028) and the other bacteria decreased slightly (p > 0.050). In the presence of P. gingivalis, T. forsythia, T. denticola and P. intermedia, a poor periodontal condition was observed. The periodontal disease increased in severity and P. gingivalis increased after GBS. A systemic inflammation resolution due to bariatric surgery in obese subjects does not seem to affect the course of periodontal disease. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Trans-generational Immune Priming Protects the Eggs Only against Gram-Positive Bacteria in the Mealworm Beetle

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Dubuffet, Aurore; Zanchi, Caroline; Boutet, Gwendoline; Moreau, Jérôme; Teixeira, Maria; Moret, Yannick

2015-01-01

In many vertebrates and invertebrates, offspring whose mothers have been exposed to pathogens can exhibit increased levels of immune activity and/or increased survival to infection. Such phenomena, called “Trans-generational immune priming” (TGIP) are expected to provide immune protection to the offspring. As the offspring and their mother may share the same environment, and consequently similar microbial threats, we expect the immune molecules present in the progeny to be specific to the microbes that immune challenged the mother. We provide evidence in the mealworm beetle Tenebrio molitor that the antimicrobial activity found in the eggs is only active against Gram-positive bacteria, even when females were exposed to Gram-negative bacteria or fungi. Fungi were weak inducers of TGIP while we obtained similar levels of anti-Gram-positive activity using different bacteria for the maternal challenge. Furthermore, we have identified an antibacterial peptide from the defensin family, the tenecin 1, which spectrum of activity is exclusively directed toward Gram-positive bacteria as potential contributor to this antimicrobial activity. We conclude that maternal transfer of antimicrobial activity in the eggs of T. molitor might have evolved from persistent Gram-positive bacterial pathogens between insect generations. PMID:26430786

Trans-generational Immune Priming Protects the Eggs Only against Gram-Positive Bacteria in the Mealworm Beetle.

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Aurore Dubuffet

2015-10-01

Full Text Available In many vertebrates and invertebrates, offspring whose mothers have been exposed to pathogens can exhibit increased levels of immune activity and/or increased survival to infection. Such phenomena, called "Trans-generational immune priming" (TGIP are expected to provide immune protection to the offspring. As the offspring and their mother may share the same environment, and consequently similar microbial threats, we expect the immune molecules present in the progeny to be specific to the microbes that immune challenged the mother. We provide evidence in the mealworm beetle Tenebrio molitor that the antimicrobial activity found in the eggs is only active against Gram-positive bacteria, even when females were exposed to Gram-negative bacteria or fungi. Fungi were weak inducers of TGIP while we obtained similar levels of anti-Gram-positive activity using different bacteria for the maternal challenge. Furthermore, we have identified an antibacterial peptide from the defensin family, the tenecin 1, which spectrum of activity is exclusively directed toward Gram-positive bacteria as potential contributor to this antimicrobial activity. We conclude that maternal transfer of antimicrobial activity in the eggs of T. molitor might have evolved from persistent Gram-positive bacterial pathogens between insect generations.

Marine echinoderms as reservoirs of antimicrobial resistant bacteria

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Catarina Marinho

2014-06-01

Full Text Available Echinoderms are benthic animals that play an important ecological role in marine communities occupying diverse trophic levels in the marine food chains. The majority of echinoderms feed on small particles of edible matter, although they can eat many kinds of food (Clark, 1968. Although, some echinoderms species has been facing an emerging demand for human consumption, particularly in Asian and Mediterranean cuisine, where these animals can be eaten raw (Kelly, 2005; Micael et al., 2009. Echinoderms own an innate immune mechanism that allows them to defend themselves from high concentrations of bacteria, viruses and fungus they are often exposed, on marine sediment (Janeway and Medzhitov, 1998, Cooper, 2003. The most frequent genera of gut bacteria in echinoderms are Vibrio, Pseudomonas, Flavobacterium, and Aeromonas; nevertheless Enterococcus spp. and Escherichia coli are also present (Harris, 1993; Marinho et al., 2013. Moreover, fecal resistant bacteria found in the aquatic environment might represent an index of marine pollution (Foti et al., 2009, Kummerer, 2009. Several studies had been lead in order to identify environmental reservoirs for antibiotic-resistant bacteria in populations of fish, echinoderms and marine mammals, and they all support the thesis that these animals may serve as reservoirs since they had acquired resistant microbial species (Johnson et al., 1998, Marinho et al., 2013, Miranda and Zemelman, 2001. However, to our knowledge, there are only available in bibliography one study of antimicrobial resistant bacteria isolated from marine echinoderms (Marinho et al., 2013, which stats that their provenience in this environment is still unclear. Antimicrobial resistance outcomes from the intensive use of antimicrobial drugs in human activities associated with various mechanisms for bacteria genetic transfer (Barbosa and Levy, 2000, Coque et al., 2008. Antibiotic-resistant bacteria enter into water environments where they are

Magnetic Bacteria.

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Nelson, Jane Bray; Nelson, Jim

1992-01-01

Describes the history of Richard Blakemore's discovery of magnetotaxic organisms. Discusses possible reasons why the magnetic response in bacteria developed. Proposes research experiments integrating biology and physics in which students investigate problems using cultures of magnetotaxic organisms. (MDH)