Effects of chlorine level on the growth of biofilm in drinking water pipes

2003 ◽  
Vol 3 (1-2) ◽  
pp. 171-177 ◽  
Author(s):  
C. Chu ◽  
C. Lu ◽  
C.M. Lee ◽  
C. Tasi
Keyword(s):  
Biofilm Formation ◽  
Bacterial Species ◽  
Free Water ◽  
Gram Negative Bacteria ◽  
Water Pipe ◽  
Water Pipes ◽  
Plate Counts ◽  
The Difference ◽  
Heterotrophic Plate Counts ◽  
Chlorine Water

Three analogous laboratory-scale water pipe systems were constructed to study the effects of three chlorine levels of finished water on the growth of biofilm. The experimental results indicated that the heterotrophic plate counts (HPCs) of biofilm for chlorine-free water were approximately 2 and 3 orders of magnitude higher than those for low-chlorine water (0.3-0.5 mg/l Cl2) and high-chlorine water (1.2-1.5 mg/l Cl2), respectively. The difference in HPCs between low-chlorine water and high-chlorine water was below 1 order. Average biofilm formation rates are 325 ATP pg/cm2 per day for chlorine-free water, 159 ATP pg/cm2 per day for low-chlorine water and 118 ATP pg/cm2 per day for high-chlorine water. Scanning electron microscope (SEM) observation showed that bacterial species separated from the biofilm were more complex than from the finished water. The Gram-negative bacteria were dominant.

scholarly journals Selection of microorganisms degrading S-Metolachlor herbicide

2007 ◽  
Vol 50 (1) ◽  
pp. 153-159 ◽  
Author(s):  
Paula Fabiane Martins ◽  
Camila Ortiz Martinez ◽  
Giselle de Carvalho ◽  
Paulo Irajara Borba Carneiro ◽  
Ricardo Antunes Azevedo ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Biofilm Formation ◽  
Bacterial Species ◽  
Enterobacter Aerogenes ◽  
Lag Phase ◽  
Herbicide Degradation ◽  
Color Changes ◽  
The Difference ◽  
Selection Of Microorganisms ◽  
Selection Of

The aim of this work was to study herbicide degradation through selected microorganisms from humus and soil subjected to different plantation systems. The following bacterial species were identified: Klebsiella pneumoniae pneumoniae GC s.B strain 1, Pseudomonas alcaligenes, Enterobacter aerogenes GC s.A and Klebsiella pneumoniae pneumoniae GC s.B strain 2. Growth studies yet suggested the possibility of a very long lag phase. Although, culture with the herbicide presented biofilm formation and there were color changes in the herbicide that could have interfered with the espectrophotometry readings. After 5 days of incubation at 35ºC, the difference in the concentration of herbicide was 14.42% on average and after 10 days, 35.01%.

scholarly journals Association of Oral Microbiota Properties on Hyaluronidase and Biofilm Formation

2021 ◽  
Vol 15 ◽  
pp. 1-7
Author(s):  
Nur Syarafina Mohd Zahir ◽  
Nabilah Huda Abdul Halim ◽  
Hanani Ahmad Yusof
Keyword(s):  
Biofilm Formation ◽  
Bacterial Species ◽  
Microtiter Plate ◽  
Oral Microbiota ◽  
Gram Negative Bacteria ◽  
Microtiter Plate Assay ◽  
Gram Staining ◽  
Biofilm Production ◽  
Biofilm Detachment ◽  
Colony Surface

Correlation between hyaluronidase (Hyl) activity and biofilm detachment in a few bacterial species was found. However, it is unclear if this association applies to bacterial species or for more general bacterial characteristics. This study determined the association between biofilm production and Hyl activity among bacterial isolates from the oral cavity of healthy subjects, and its association with Gram staining group, colony surface morphology and bacteria shape.  The swab was taken from the tongue, cheek and entire teeth surfaces of 35 subjects, and tested for biofilm through modified microtiter plate assay while Hyl production was screened through HA rapid plate method. Forty-four isolates were found, each 50% are Gram-positive, and Gram-negative bacteria, with the majority are cocci and non-mucoid colony. More than 70% of isolates are moderate and strong; (n= 17, 38.6%) and (n=15, 34.1%) respectively for biofilm production; and 68.2% are Hyl producer. A significant association was found between Hyl and bacterial shape (p=0.018) and colony morphology (p=0.018), while other association is not significantly measured, including between Hyl and biofilm (p=0.659). This study showed that biofilm production is not affected by the characteristics of the bacteria to produce or not produce hyaluronidase. Meanwhile, Hyl production is prone in rod shape and mucoid isolates which need further investigations.

Effect of dead cells on biofouling in the reverse osmosis process

2013 ◽  
Vol 13 (5) ◽  
pp. 1396-1401
Author(s):  
Myung Seop Shin ◽  
Lan Hee Kim ◽  
Sung-Jo Kim ◽  
Chang-Min Kim ◽  
Kyu-Jung Chae ◽  
...  
Keyword(s):  
Reverse Osmosis ◽  
Biofilm Formation ◽  
Extracellular Polymeric Substances ◽  
Live Cells ◽  
Feed Water ◽  
Fouling Control ◽  
Flux Decline ◽  
Low Concentrations ◽  
Plate Counts ◽  
Heterotrophic Plate Counts

Biofilm formation in membrane processes causes a flux decline, pressure drop increase, and other adverse effects. Understanding the mechanisms of fouling, control, and cleaning are important in order to resolve fouling problems. In this paper, the effect of cell viability on biofouling was studied via a feed water analysis and membrane autopsy. Pseudomonas aeruginosa PAO1 was used as the model bacteria. Biofouling tests were divided into two parts: live cells and dead cells (autoclaved cells). The feed water was periodically collected every 3 h to analyze the total direct counts (TDCs), heterotrophic plate counts (HPCs), and extracellular polymeric substances (EPS). A membrane autopsy was performed to characterize the fouled membrane through TDCs and EPS. When dead cells were inoculated into the feed water, low concentrations of TDCs and EPS were measured in both the feed water and fouled membrane. As a result, it was determined that initial flux decline by biofouling can be reduced if feedwater is disinfected before the reverse osmosis process.

scholarly journals Outer Membrane Vesicles Released From Aeromonas Strains Are Involved in the Biofilm Formation

2021 ◽  
Vol 11 ◽  
Author(s):  
Soshi Seike ◽  
Hidetomo Kobayashi ◽  
Mitsunobu Ueda ◽  
Eizo Takahashi ◽  
Keinosuke Okamoto ◽  
...  
Keyword(s):  
Amino Acid ◽  
Outer Membrane ◽  
Biofilm Formation ◽  
Bacterial Species ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Amino Acid Sequences ◽  
Bacterial Biofilm ◽  
Gram Negative Bacteria ◽  
Gram Negative

Aeromonas spp. are Gram-negative rod-shaped bacteria ubiquitously distributed in diverse water sources. Several Aeromonas spp. are known as human and fish pathogens. Recently, attention has been focused on the relationship between bacterial biofilm formation and pathogenicity or drug resistance. However, there have been few reports on biofilm formation by Aeromonas. This study is the first to examine the in vitro formation and components of the biofilm of several Aeromonas clinical and environmental strains. A biofilm formation assay using 1% crystal violet on a polystyrene plate revealed that most Aeromonas strains used in this study formed biofilms but one strain did not. Analysis of the basic components contained in the biofilms formed by Aeromonas strains confirmed that they contained polysaccharides containing GlcNAc, extracellular nucleic acids, and proteins, as previously reported for the biofilms of other bacterial species. Among these components, we focused on several proteins fractionated by SDS-PAGE and determined their amino acid sequences. The results showed that some proteins existing in the Aeromonas biofilms have amino acid sequences homologous to functional proteins present in the outer membrane of Gram-negative bacteria. This result suggests that outer membrane components may affect the biofilm formation of Aeromonas strains. It is known that Gram-negative bacteria often release extracellular membrane vesicles from the outer membrane, so we think that the outer membrane-derived proteins found in the Aeromonas biofilms may be derived from such membrane vesicles. To examine this idea, we next investigated the ability of Aeromonas strains to form outer membrane vesicles (OMVs). Electron microscopic analysis revealed that most Aeromonas strains released OMVs outside the cells. Finally, we purified OMVs from several Aeromonas strains and examined their effect on the biofilm formation. We found that the addition of OMVs dose-dependently promoted biofilm formation, except for one strain that did not form biofilms. These results suggest that the OMVs released from the bacterial cells are closely related to the biofilm formation of Aeromonas strains.

Modulation of Gut Microbiota through Dietary Phytochemicals as a Novel Anti-infective Strategy

2020 ◽  
Vol 17 (4) ◽  
pp. 498-506 ◽  
Author(s):  
Pavan K. Mujawdiya ◽  
Suman Kapur
Keyword(s):  
Microbial Community ◽  
Quorum Sensing ◽  
Population Density ◽  
Gut Microbiota ◽  
Biofilm Formation ◽  
Chemical Interaction ◽  
Bacterial Species ◽  
Critical Role ◽  
Bacterial Cells ◽  
Gut Microbes

: Quorum Sensing (QS) is a phenomenon in which bacterial cells communicate with each other with the help of several low molecular weight compounds. QS is largely dependent on population density, and it triggers when the concentration of quorum sensing molecules accumulate in the environment and crosses a particular threshold. Once a certain population density is achieved and the concentration of molecules crosses a threshold, the bacterial cells show a collective behavior in response to various chemical stimuli referred to as “auto-inducers”. The QS signaling is crucial for several phenotypic characteristics responsible for bacterial survival such as motility, virulence, and biofilm formation. Biofilm formation is also responsible for making bacterial cells resistant to antibiotics. : The human gut is home to trillions of bacterial cells collectively called “gut microbiota” or “gut microbes”. Gut microbes are a consortium of more than 15,000 bacterial species and play a very crucial role in several body functions such as metabolism, development and maturation of the immune system, and the synthesis of several essential vitamins. Due to its critical role in shaping human survival and its modulating impact on body metabolisms, the gut microbial community has been referred to as “the forgotten organ” by O`Hara et al. (2006) [1]. Several studies have demonstrated that chemical interaction between the members of bacterial cells in the gut is responsible for shaping the overall microbial community. : Recent advances in phytochemical research have generated a lot of interest in finding new, effective, and safer alternatives to modern chemical-based medicines. In the context of antimicrobial research various plant extracts have been identified with Quorum Sensing Inhibitory (QSI) activities among bacterial cells. This review focuses on the mechanism of quorum sensing and quorum sensing inhibitors isolated from natural sources.

Defensive Role of Plant-Derived Secondary Metabolites: Indole and Its’ Derivatives

2020 ◽  
Vol 9 (2) ◽  
pp. 78-88
Author(s):  
Mulugeta Mulat ◽  
Raksha Anand ◽  
Fazlurrahman Khan
Keyword(s):  
Biofilm Formation ◽  
Growth And Development ◽  
Functional Role ◽  
Plant Pathogens ◽  
Bacterial Species ◽  
Indole Derivatives ◽  
Resistance Level ◽  
Defensive Role ◽  
Insect Attack

The diversity of indole concerning its production and functional role has increased in both prokaryotic and eukaryotic systems. The bacterial species produce indole and use it as a signaling molecule at interspecies, intraspecies, and even at an interkingdom level for controlling the capability of drug resistance, level of virulence, and biofilm formation. Numerous indole derivatives have been found to play an important role in the different systems and are reported to occur in various bacteria, plants, human, and plant pathogens. Indole and its derivatives have been recognized for a defensive role against pests and insects in the plant kingdom. These indole derivatives are produced as a result of the breakdown of glucosinolate products at the time of insect attack or physical damages. Apart from the defensive role of these products, in plants, they also exhibit several other secondary responses that may contribute directly or indirectly to the growth and development. The present review summarized recent signs of progress on the functional properties of indole and its derivatives in different plant systems. The molecular mechanism involved in the defensive role played by indole as well as its’ derivative in the plants has also been explained. Furthermore, the perspectives of indole and its derivatives (natural or synthetic) in understanding the involvement of these compounds in diverse plants have also been discussed.

scholarly journals Endotoxin contamination in the dental surgery

2007 ◽  
Vol 56 (9) ◽  
pp. 1230-1234 ◽  
Author(s):  
M. K. Huntington ◽  
J. F. Williams ◽  
C. D. Mackenzie
Keyword(s):  
Bacterial Load ◽  
Dental Surgery ◽  
Paired Samples ◽  
Dental Procedures ◽  
Large Numbers ◽  
Endotoxin Exposure ◽  
Endotoxin Contamination ◽  
Plate Counts ◽  
High Concentrations ◽  
Heterotrophic Plate Counts

Dental waterlines contain large numbers of Gram-negative bacteria. Endotoxin, a component of such organisms, has significant health implications. Paired samples of dental unit water and the aerosols generated during dental procedures were collected, and assayed for bacteria and endotoxin levels, using heterotrophic plate counts and the Limulus amoebocyte lysate test. Consistent with published studies, the extent of bacterial contamination in the dental waters sampled for this investigation surpassed the levels associated with potable water, with counts in excess of 2.0×106 c.f.u. ml−1 in some samples. Correspondingly high concentrations of endotoxin [up to 15 000 endotoxin units (EU) ml−1] were present in the water. A statistically significant Spearman correlation coefficient of ρ=0.94 between endotoxin (EU ml−1) and bacterial load (c.f.u. ml−1) was demonstrated. All of the aerosol samples contained detectable endotoxin. Further studies of the consequences of dental endotoxin exposure, and evaluation of means to prevent exposure, are warranted.

Free Water Influence on the Dynamic Tensile Behaviour of Concrete

2011 ◽  
Vol 82 ◽  
pp. 45-50 ◽  
Author(s):  
Benjamin Erzar ◽  
Pascal Forquin
Keyword(s):  
Dynamic Behaviour ◽  
Free Water ◽  
Dynamic Strength ◽  
Fragmentation Process ◽  
Tensile Behaviour ◽  
Water Influence ◽  
Micro Cracks ◽  
The World ◽  
The Difference ◽  
Impact Experiments

Concrete is a material used all over the world for civil engineering but the mechanisms governing its dynamic behaviour are still not well understood. In this work, spalling tests and edge-on impact experiments have been used to determine the influence of the free-water contained in pores and micro-cracks on the dynamic strength and on the fragmentation process. Moreover, spalling tests have been also used to identify the main mechanisms leading to the difference of behaviour observed between wet and dry concrete.

Archaeal biofilms: widespread and complex

2013 ◽  
Vol 41 (1) ◽  
pp. 393-398 ◽  
Author(s):  
Sabrina Fröls
Keyword(s):  
Biofilm Formation ◽  
Extracellular Polymeric Substances ◽  
Bacterial Species ◽  
Surface Adhesion ◽  
Form Complex ◽  
Abiotic Surfaces ◽  
Archaeal Species ◽  
Physical And Chemical ◽  
Insight Into ◽  
Mixed Communities

Biofilms or multicellular structures become accepted as the dominant microbial lifestyle in Nature, but in the past they were only studied extensively in bacteria. Investigations on archaeal monospecies cultures have shown that many archaeal species are able to adhere on biotic and abiotic surfaces and form complex biofilm structures. Biofilm-forming archaea were identified in a broad range of extreme and moderate environments. Natural biofilms observed are mostly mixed communities composed of archaeal and bacterial species of various abundances. The physiological functions of the archaea identified in such mixed communities suggest a significant impact on the biochemical cycles maintaining the flow and recycling of the nutrients on earth. Therefore it is of high interest to investigate the characteristics and mechanisms underlying the archaeal biofilm formation. In the present review, I summarize and discuss the present investigations of biofilm-forming archaeal species, i.e. their diverse biofilm architectures in monospecies or mixed communities, the identified EPSs (extracellular polymeric substances), archaeal structures mediating surface adhesion or cell–cell connections, and the response to physical and chemical stressors implying that archaeal biofilm formation is an adaptive reaction to changing environmental conditions. A first insight into the molecular differentiation of cells within archaeal biofilms is given.

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