Enterococcus faecalis and Vibrio harveyicolonize low-density polyethylene and biodegradable plastics under marine conditions

2020 ◽  
Vol 367 (15) ◽  
Author(s):  
Ilef Hchaichi ◽  
Francesca Bandini ◽  
Giulia Spini ◽  
Mohamed Banni ◽  
Pier Sandro Cocconcelli ◽  
...  
Keyword(s):  
Enterococcus Faecalis ◽  
Biofilm Formation ◽  
Aquatic Ecosystems ◽  
Pathogenic Bacteria ◽  
Sea Water ◽  
Vibrio Harveyi ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Plastic Surfaces ◽  
Scanning Electron

ABSTRACT Conventional plastics and bioplastics are known to accumulate in aquatic ecosystems, emerging as new surfaces for biofilm formation and gene exchanges. On the other hand, the fate of non-conventional bioplastics in the marine environment is still unclear. In this study we have measured, by means of crystal violet test and scanning electron microscopy (SEM), the ability of two model bacteria, Vibrio harveyi and Enterococcus faecalis, to form biofilms on low-density polyethylene (PE), polylactic acid (PLA) and starch-based bioplastic (SBB) surfaces. Experiments were conducted in artificial sea water, incubating squares of 3 cm2 of the three plastics with the two model microorganisms and sampling overnight, and at 3 and 6 days. The presence of biofilms on plastic surfaces was detected from day one of incubation and SBB was the material with the highest biofilm formation. E. faecalis formed the thickest biofilm after 3 days with PLA and SBB, but did not remain stable, and after 6 days with PE. The maximum biofilm formation of V. harveyi was obtained overnight with SBB and PE, and after 3 days with PLA. Our data indicate that both plastic and bioplastics support the formation of biofilms of model pathogenic bacteria, highlighting potential concerns for human health.

scholarly journals Extract from phyllosphere bacteria with antibiofilm and quorum quenching activity to control several fish pathogenic bacteria

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Olivia Nathalia ◽  
Diana Elizabeth Waturangi
Keyword(s):  
Streptococcus Agalactiae ◽  
Aeromonas Hydrophila ◽  
Biofilm Formation ◽  
Pathogenic Bacteria ◽  
Vibrio Harveyi ◽  
Quorum Quenching ◽  
Indicator Bacteria ◽  
Antibiofilm Activity ◽  
Fish Pathogen ◽  
Phyllosphere Bacteria

Abstract Objective The objective of this research were to screen quorum quenching activity compound from phyllosphere bacteria as well as antibiofilm activity against several fish pathogen bacteria such as Aeromonas hydrophila, Streptococcus agalactiae, and Vibrio harveyi. Results We found eight phyllosphere bacteria isolates with potential quorum quenching activity to inhibit Chromobacterium violaceum as indicator bacteria. Crude extracts (20 mg/mL) showed various antibiofilm activity against fish pathogenic bacteria used in this study. Isolate JB 17B showed the highest activity to inhibit biofilm formation of A. hydrophila and V. harveyi, meanwhile isolate JB 3B showed the highest activity to inhibit biofilm of S. agalactiae. From destruction assay, isolate JB 8F showed the highest activity to disrupt biofilm of A. hydrophila isolate JB 20B showed the highest activity to disrupt biofilm of V. harveyi, isolate JB 17B also showed the highest activity to disrupt biofilm of S. agalactiae.

scholarly journals Fabrication of raw and oxidized saw dust reinforced low density polyethylene (LDPE) composites and investigation of their physico-mechanical properties

2013 ◽  
Vol 47 (4) ◽  
pp. 365-372 ◽  
Author(s):  
S Sultana ◽  
HP Nur ◽  
T Saha ◽  
M Saha
Keyword(s):  
Mechanical Properties ◽  
Mangifera Indica ◽  
Flexural Modulus ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Electron Micrograph ◽  
Scanning Electron Micrograph ◽  
Saw Dust ◽  
Ldpe Composites ◽  
Scanning Electron

In this research work, cellulosic waste mango (Mangifera indica) saw dust used as the reinforcing material with low density polyethylene (LDPE). A number of samples of saw dust reinforced low density polyethylene (LDPE) composites were prepared by compression moulding technique. In order to improve the mechanical properties of saw dust-LDPE composites, unbleached raw saw dust fibers were modified by oxidation using sodium hypochlorite. FT-IR spectroscopic and scanning electron micrograph (SEM) analyses were done and the results showed the evidence of positive oxidation reaction. The effects of oxidized saw dust on the performance of oxidized saw dust reinforced LDPE composites were studied comparing with the raw saw dust-LDPE composites. The effects of fiber content on the physico-mechanical properties of composites were also studied by preparing the composites with different percentage of fiber loading (from 7.5 wt% to 30 wt%) for each type of composite. Mechanical properties such as tensile strength, tensile modulus, elongation at break, flexural strength, flexural modulus of the resulting composite were measured. Better results were obtained from oxidized saw dust-LDPE composites. Scanning electron micrograph and water absorption tests were carried out for all composites and improved results were found for oxidized saw dust-LDPE composites. Bangladesh J. Sci. Ind. Res. 47(4), 365-372, 2012 DOI: http://dx.doi.org/10.3329/bjsir.v47i4.14065

Natural weather, soil burial and sea water ageing of low-density polyethylene: Effect of starch/linear low-density polyethylene masterbatch

2012 ◽  
Vol 129 (1) ◽  
pp. 449-457 ◽  
Author(s):  
M. Elanmugilan ◽  
P. A. Sreekumar ◽  
N. K. Singha ◽  
Mamdouh A. Al-Harthi ◽  
S. K. De
Keyword(s):  
Sea Water ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Linear Low Density Polyethylene ◽  
Soil Burial

METHODOLOGICAL APPROACHES TO THE STUDY OF FORMATION OF BIOFILMS BY CONDITIONALLY PATHOGENIC AND PATHOGENIC ENTEROSBACTERIES

2018 ◽  
Vol 1 (1) ◽  
pp. 50-58
Author(s):  
A. B. Kononenko ◽  
◽  
I. B. Pavlova ◽  
D. A. Bannikova ◽  
S. V. Britova ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Nutrient Medium ◽  
Biofilm Formation ◽  
Pathogenic Bacteria ◽  
Osmic Acid ◽  
Liquid Nutrient Medium ◽  
Petri Dishes ◽  
Peptone Broth ◽  
Scanning Electron

To study the process of biofilm formation, microorganisms were cultured in 96-well plates, on meat-peptone broth, stained with a 0,1% solution of crystalline violet for 10...15 minutes, after which the unbound dye was washed off. The quantitative accounting of the bound dye was carried out by spectrophotometry at a wavelength of 490 nm. The technique for making bacterial preparations for light and scanning electron microscopy on dodged glasses immersed in Petri dishes with a liquid nutrient medium is proposed. A suspension of bacteria at a concentration of 105 m.k/ml in a volume of 5 ml was shaken on Vortex apparatus and introduced into Petri dishes with 20 ml of meat-peptone broth. Sterile non-greased cover glasses were placed on sterile object glasses and immersed in a liquid nutrient medium in Petri dishes. The material was incubated for 18...24 hours at 37 °C. Then the cover slips were removed with tweezers and some of them were stained with 1% aqueous solution of methylene blue (for light microscopy), and some were placed in Petri dishes with bottomed filters (for electron microscopy). The latter, in order to preserve natural architectonics, were fixed in vivo by pairs of 25% glutaraldehyde for 3...5 hours. Vapors of 2...4% osmic acid solution were used for 2...3-minutes to contrast the preparations. After treatment with vapors of osmic acid, biofilms with included bacteria acquired yellowish or brown color. The obtained preparations after dehydration with propylene oxide vapors and spraying with gold ions were examined in a scanning electron microscope (SEM). The technique allows us to study the phases of development of biofilms and obtain objective data on the morphology of populations of pathogenic and conditionally pathogenic bacteria without disturbing natural architectonics. It is shown that the intensity of biofilm formation by pathogenic microorganisms, such as salmonella, Yersinia, Staphylococcus aureus was slightly higher than that of non-pathogenic: Escherichia, Proteus, Citrobacter, Enterobacter.

Biodegradation of Low Density Polyethylene (LDPE) Composite Filled with Cellulose and Cellulose Acetate

2014 ◽  
Vol 896 ◽  
pp. 314-317 ◽  
Author(s):  
Halimatuddahliana ◽  
Ahmad Mulia Rambe
Keyword(s):  
Weight Loss ◽  
Cellulose Acetate ◽  
The Other ◽  
Low Density Polyethylene ◽  
Processing Temperature ◽  
Low Density ◽  
Open Environment ◽  
Ldpe Composites ◽  
Scanning Electron ◽  
Microbial Attack

A comparative study was conducted for the biodegradation of low density polyethylene (LDPE) composites filled with cellulose (C) and cellulose acetate (CA). Composites were prepared with the content of each filler of 10% (by weight) using an extruder at processing temperature of 125°C.Biodegradation processes were done by burying in the soil and by hanging in an open environment for four months. The percentage of weight loss of pure LDPE and composites due to the degradation were observed based on the weight reduction of the composites and supported by scanning electron microscopy (SEM). The results indicated pure LDPE was not susceptible to microbial attack as the percentage of weight loss were constant. However, the composites filled with cellulose were relatively more susceptible to degradation as compared with composites filled cellulose acetate. Here, the percentage of weight loss of composites filled cellulose were higher than the composites filled cellulose acetate. On the other hand, the biodegradation processes by hanging in open environment were relatively faster than burying in soil for both types of composites. These results were confirmed by SEM which have shown some cavities.

scholarly journals Multiplex CRISPRi System Enables the Study of Stage-Specific Biofilm Genetic Requirements in Enterococcus faecalis

mBio ◽  
2020 ◽  
Vol 11 (5) ◽  
Author(s):  
Irina Afonina ◽  
June Ong ◽  
Jerome Chua ◽  
Timothy Lu ◽  
Kimberly A. Kline
Keyword(s):  
Enterococcus Faecalis ◽  
Biofilm Formation ◽  
Pathogenic Bacteria ◽  
Expression System ◽  
Multidrug Resistant ◽  
Essential Genes ◽  
Host Bacterium ◽  
Content Type ◽  
Wide Range ◽  
Life Threatening

ABSTRACT Enterococcus faecalis is an opportunistic pathogen, which can cause multidrug-resistant life-threatening infections. Gaining a complete understanding of enterococcal pathogenesis is a crucial step in identifying a strategy to effectively treat enterococcal infections. However, bacterial pathogenesis is a complex process often involving a combination of genes and multilevel regulation. Compared to established knockout methodologies, CRISPR interference (CRISPRi) approaches enable the rapid and efficient silencing of genes to interrogate gene products and pathways involved in pathogenesis. As opposed to traditional gene inactivation approaches, CRISPRi can also be quickly repurposed for multiplexing or used to study essential genes. Here, we have developed a novel dual-vector nisin-inducible CRISPRi system in E. faecalis that can efficiently silence via both nontemplate and template strand targeting. Since the nisin-controlled gene expression system is functional in various Gram-positive bacteria, the developed CRISPRi tool can be extended to other genera. This system can be applied to study essential genes, genes involved in antimicrobial resistance, and genes involved in biofilm formation and persistence. The system is robust and can be scaled up for high-throughput screens or combinatorial targeting. This tool substantially enhances our ability to study enterococcal biology and pathogenesis, host-bacterium interactions, and interspecies communication. IMPORTANCE Enterococcus faecalis causes multidrug-resistant life-threatening infections and is often coisolated with other pathogenic bacteria from polymicrobial biofilm-associated infections. Genetic tools to dissect complex interactions in mixed microbial communities are largely limited to transposon mutagenesis and traditional time- and labor-intensive allelic-exchange methods. Built upon streptococcal dCas9, we developed an easily modifiable, inducible CRISPRi system for E. faecalis that can efficiently silence single and multiple genes. This system can silence genes involved in biofilm formation and antibiotic resistance and can be used to interrogate gene essentiality. Uniquely, this tool is optimized to study genes important for biofilm initiation, maturation, and maintenance and can be used to perturb preformed biofilms. This system will be valuable to rapidly and efficiently investigate a wide range of aspects of complex enterococcal biology.

scholarly journals Formation of biofilms of pathogenic bacteria and the effect of a new disinfectant

2020 ◽  
Vol 17 ◽  
pp. 00204
Author(s):  
I.B. Pavlova ◽  
A.B. Kononenko ◽  
G.S. Tolmacheva ◽  
G.G. Kardash ◽  
A.Yu. Rytsarev
Keyword(s):  
Biofilm Formation ◽  
Salmonella Enteritidis ◽  
Pathogenic Bacteria ◽  
Bactericidal Effect ◽  
Biological Features ◽  
Development Phases ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
And Staphylococcus Aureus ◽  
Scanning Electron

The article presents results of experimental study of biofilm formation by pathogenic bacteria Pseudomonas aeruginosa, Salmonella enteritidis and Staphylococcus aureus. Using the method of investigation of microbiological objects by light and scanning electron microscopes, preserving their architectonics, process of biofilm formation and its development phases were shown. Morphological and biological features of the effects of a nanotechnology preparations containing Chlorhexidine-base were studied. Its bactericidal effect on biofilms of pathogenic bacteria was shown.

scholarly journals Fabrication of LDPE/PS interpolymer resin particles through a swelling suspension polymerization approach

e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 361-368
Author(s):  
Nianqing Zhu ◽  
Hailong Chen ◽  
Xinxing Gao ◽  
Rongjie Hou ◽  
Zhongbing Ni ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Suspension Polymerization ◽  
Low Density Polyethylene ◽  
Polymerization Temperature ◽  
Low Density ◽  
Polymerization Time ◽  
Initiator Concentration ◽  
Spectroscopy Analysis ◽  
Swelling Agent ◽  
Scanning Electron

AbstractA facile method to prepare low-density polyethylene (LDPE)/polystyrene (PS) interpolymer resin particles by swelling suspension polymerization without addition of extra swelling agent was developed. The polymerization temperature, polymerization time, and initiator concentration were investigated. Fourier transform infrared spectroscopy analysis confirmed that the LDPE/PS interpolymer resin particles were successfully prepared and a small amount of PS-g-LDPE existed in the resin. Scanning electron microscopy revealed that PS was uniformly distributed in the LDPE matrix, indicating excellent compatibility between PS and LDPE. The mechanical properties of LDPE/PS interpolymer resin were intermediate between PS and LDPE polymers.

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