The document investigates the role of the regulatory protein ArcR in biofilm formation of Streptococcus gordonii. Experiments showed that an arcR mutant strain formed biofilms that were less stable and easily detached compared to wild-type biofilms. Atomic force microscopy and crystal violet assays demonstrated reduced biofilm formation in the mutant strain. While cell surface hydrophobicity was unchanged, competition assays revealed an impairment in long-term survival of the mutant strain in both planktonic and biofilm environments. Future work will further examine the mechanisms by which ArcR affects biofilm formation and planktonic survival.
Nowadays synthesis of nanomaterials by using bio-root is limelight of modern nanotechnology. In the present investigation, we have isolated four strains viz: KFRI 330 (A), KFRI 332 (B), KFRI 351 (C) and KFRI 352 (D) of Beauveria bassiana from the forest soils in Kerala. Spore count was tested for all the strains of B. bassiana stored in the laboratory. Silver nanoparticles were synthesized from the four strains of B. bassiana and the formation of nanoparticles was observed within 48 hours. The synthesized silver nanoparticle has been characterized by UV-Vis spectroscopy, FT-IR and TEM analysis. The appearance of UV-Vis Peak (SPR 440 nm) revealed the reduction of silver metal ions to silver nanoparticles by using the fungal strains. The possible bio-molecules involved in nanoparticles synthesis was identified by HPLC analysis. The functional groups involved in the silver nanoparticles synthesis were identified. The amide group is responsible for the synthesis of silver nanoparticles. From the TEM analysis, the size of the AGNPs has been measured as 4-70 nm (mean 10.7±0.04 nm). It was evident from the HPLC result that primary amines act on capping as a well as a stabilizing agent.
Nowadays synthesis of nanomaterials by using bio-root is limelight of modern nanotechnology. In the present investigation, we have isolated four strains viz: KFRI 330 (A), KFRI 332 (B), KFRI 351 (C) and KFRI 352 (D) of Beauveria bassiana from the forest soils in Kerala. Spore count was tested for all the strains of B. bassiana stored in the laboratory. Silver nanoparticles were synthesized from the four strains of B. bassiana and the formation of nanoparticles was observed within 48 hours. The synthesized silver nanoparticle has been characterized by UV-Vis spectroscopy, FT-IR and TEM analysis. The appearance of UV-Vis Peak (SPR 440 nm) revealed the reduction of silver metal ions to silver nanoparticles by using the fungal strains. The possible bio-molecules involved in nanoparticles synthesis was identified by HPLC analysis. The functional groups involved in the silver nanoparticles synthesis were identified. The amide group is responsible for the synthesis of silver nanoparticles. From the TEM analysis, the size of the AGNPs has been measured as 4-70 nm (mean 10.7±0.04 nm). It was evident from the HPLC result that primary amines act on capping as a well as a stabilizing agent.
Use of stable and radio isotopes to understand the plant physiological processRAHUL GOPALE
Introduction
what is isotope ?
Types of Isotopes
Isotopic Labelling
ADVANTAGES AND DISADVANTAGES OF ISOTOPIC STUDY
APPLICATIONS OF ISOTOPES IN AGRICULTURE
Principle isotopes used in plant-soil studies
Case studies
FUTURE THRUSTS OF ISOTOPIC STUDY
CONCLUSIONS
REFERENCES
Term ‘Nano’ comes from the Greek word ‘nanos’ meaning dwarf and denotes a measurement on the scale of one billionth (10⁹) of a meter in size. Nanoparticles are defined as a particulate dispersions of solid particles with atleast one dimension at a size range of 10-1000 nm. The most important feature of Nanoparticles is their surface area to volume aspect ratio, allowing them to interact with other particles easier.
Identification of Nitrogen Fixing Cyanobacteria ByRahul Anand
Cyanobacteria are important members of the "Microbial World" that can fix atmospheric Nitrogen. They can prove to be excellent alternative against chemical fertilizers.
The GSCOP Infographic - is an Infographic from MakingBusinessMatter.co.uk
You can visit our site and see more infographics here -
http://www.makingbusinessmatter.co.uk/blog/infographics/
‘Do not start with Powerpoint – 7 Pieces of Essential Preparation’ is about sharing with you how the very best suppliers achieve greater influence in their presentations. For most, the need to ‘write a presentation’ or ‘create a deck for me’ begins with opening a new Powerpoint file. Stop. Please do not.
While big corporations are dismissing it as "below the line" marketing, for a cash strapped startup these innovative and inventive tactics are the only ones the can afford to use. We look at how Slovenian on-line retailer mimovrste=) used these techniques to enter and win the market.
Use of stable and radio isotopes to understand the plant physiological processRAHUL GOPALE
Introduction
what is isotope ?
Types of Isotopes
Isotopic Labelling
ADVANTAGES AND DISADVANTAGES OF ISOTOPIC STUDY
APPLICATIONS OF ISOTOPES IN AGRICULTURE
Principle isotopes used in plant-soil studies
Case studies
FUTURE THRUSTS OF ISOTOPIC STUDY
CONCLUSIONS
REFERENCES
Term ‘Nano’ comes from the Greek word ‘nanos’ meaning dwarf and denotes a measurement on the scale of one billionth (10⁹) of a meter in size. Nanoparticles are defined as a particulate dispersions of solid particles with atleast one dimension at a size range of 10-1000 nm. The most important feature of Nanoparticles is their surface area to volume aspect ratio, allowing them to interact with other particles easier.
Identification of Nitrogen Fixing Cyanobacteria ByRahul Anand
Cyanobacteria are important members of the "Microbial World" that can fix atmospheric Nitrogen. They can prove to be excellent alternative against chemical fertilizers.
The GSCOP Infographic - is an Infographic from MakingBusinessMatter.co.uk
You can visit our site and see more infographics here -
http://www.makingbusinessmatter.co.uk/blog/infographics/
‘Do not start with Powerpoint – 7 Pieces of Essential Preparation’ is about sharing with you how the very best suppliers achieve greater influence in their presentations. For most, the need to ‘write a presentation’ or ‘create a deck for me’ begins with opening a new Powerpoint file. Stop. Please do not.
While big corporations are dismissing it as "below the line" marketing, for a cash strapped startup these innovative and inventive tactics are the only ones the can afford to use. We look at how Slovenian on-line retailer mimovrste=) used these techniques to enter and win the market.
Bacterial Community Profiling of the Arabian Sea Oxygen Minimum Zone Sediments using Cultivation Independent Approach by Baby Divya in Examines in Marine Biology and Oceanography
DeBrota M, Penry O - Isolation and Classification of Soil Microorganisms with...Michael DeBrota
As part of the BIO220 Microbiology course at Rose-Hulman Institute of Technology, our group conducted a study isolating and classifying various soil microorganisms with suspected antimicrobial properties.
Isolation of typical marine bacteria by dilution culture - growth, maintenanc...ITSON
Isolation of Typical Marine Bacteria by Dilution Culture: Growth, Maintenance, and Characteristics of Isolates under Laboratory Conditions - FRITS SCHUT
Synthesis and evaluation of bactericidal properties of CuO nanoparticles agai...Nanomedicine Journal (NMJ)
Objective(s):
CuO is one of the most important transition metal oxides due to its captivating properties. It is used in various technological applications such as high critical temperature superconductors, gas sensors, in photoconductive applications, and so on. Recently, it has been used as an antimicrobial agent against various bacterial species.
Materials and Methods:
Here, we synthesized CuO nanoparticles (NPs) and explored the antibacterial activity of CuO NPs preparation.
Results:
Single crystalline nanoparticles of copper oxide having almost uniform particle size of 5-6 nm has been synthesized by a facile and versatile route. XRD spectra confirmed the formation of single phase CuO NPs. Transmission electron microscopy results corroborate well with XRD results. The technique employed is free from toxic solvents, organics and amines, is based on a simple reaction of copper sulfate and de-ionized water (DI), and their bactericidal effects against of Aeromonas hydrophila ATCC 7966T bacteria were investigated. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) with liquid culture for all of the Aeromonas hydrophila culture Medias was done.
Conclusion:
Present study confirms that Copper oxide nanoparticles have great promise as antimicrobial agent against Aeromonas hydrophila.
Comparative study on screening methods of polyhydroxybutyrate (PHB) producing...inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Atomic force spectroscopy ~AFS! was used to measure interaction forces between the tip and nanostructured layers of poly~o-ethoxyaniline! ~POEA! in pure water and CuSO4 solutions. When the tip approach and retraction were carried out at low speeds, POEA chains could be physisorbed onto the Si3N4 tip
via nonspecific interactions.We conjecture that while detaching, POEA chains were stretched and the estimated
chain lengths were consistent with the expected values from the measured POEA molecular weight. The effects
from POEA doping could be investigated directly by performing AFS measurements in a liquid cell, with the
POEA film exposed to liquids of distinct pH values. For pH 6.0, the force curves normally displayed an
attractive region for POEA, but at lower pH values—where POEA is protonated—the repulsive double-layer
forces dominated. Measurements in the liquid cell could be further exploited to investigate how the film
morphology and the force curve are affected when impurities are deliberately introduced in the liquid. The
shape of the force curves and the film morphology depended on the concentration of heavy metal in the liquid
cell. AFS may therefore be used to study the interaction between film and analyte, with important implications
for the understanding of mechanisms governing the sensing ability of taste sensors.
Study of poly(o ethoxyaniline) interactions with herbicides and evaluation of...
Eurobiofilms poster
1. The role of the regulatory protein ArcR in
Streptococcus gordonii biofilm formation
Jill C. Robinson1, Dr. Nicholas Jakubovics1,
Dr. Matthew German2, Prof. Waldemar Vollmer3
1. Oral Biology, Centre for Oral Health Research, Newcastle University
2. Dental Materials, Centre for Oral Health Research, Newcastle University,
3. Centre for Bacterial Cell Biology, Institute of Cell and Molecular Biosciences, Newcastle University
Introduction
Streptococcus gordonii, an oral commensal organism and primary coloniser
of the surfaces within the oral cavity, is known to play an important role in the
formation of dental plaque1. Preliminary studies have shown that the arcR
gene, encoding the arginine-dependent transcriptional regulator ArcR, is
required for stable biofilm formation in S. gordonii. Deletion of arcR results in
a strain that forms biofilms that appear superficially similar to wild-type
biofilms, but are extremely unstable and easily break apart.
Aims
To quantify differences in biofilm formation by the arcR mutant
Measure cell surface hydrophobicity in the arcR mutant
Investigate whether arcR mutant can be complemented by co-culture with
wild-type
Methods
Atomic force microscopy (AFM) – air imaging and force spectroscopy: air
imaging was carried out on air-dried dehydrated biofilms. Force
spectroscopy was used to measure the stiffness of the biofilms by
tapping and dragging a silicon probe across the cell surfaces.
Crystal violet assay: biofilms were grown in 6-well plates, stained in
crystal violet, and the absorbance measured at A570 in order to quantify
biofilm growth.
Microbial adhesion to hexadecane (MATH) assay: the addition of n-
hexadecane to an aqueous suspension of cells allowed the
measurement of cell surface hydrophobicity. The proportion of cells
partitioning into the hexadecane phase (“% hydrophobicity”) was
determined by the reduction in A450 of the aqueous phase.
Competition assays – planktonic and sessile: Equal concentrations of the
wild-type S. gordonii and arcR mutant strains were grown together in
planktonic and biofilm co-cultures, to assess the relative fitness of each
strain.
Results
Discussion and conclusions
The arcR mutant strain is significantly impaired in biofilm formation.
Both the crystal violet assays and the AFM imaging showed reduced
biofilm formation in the arcR mutant strain, in comparison to the wild-type.
The MATH assay showed no significant differences between the cell
surface hydrophobicity of the arcR mutant strain and the wild-type.
Competition assays – both planktonic and biofilm – showed an impairment
in long-term survival (>48h) in the arcR mutant strain, in addition to the
previously observed impairment in biofilm formation. This could be due to
hydrogen peroxide build-up during growth – it may be that the arcR strain
is more susceptible to hydrogen peroxide exposure than the wild-type.
Future work
AFM imaging and force spectroscopy of hydrated biofilms under liquid
conditions, as dehydrated biofilms were artificial in appearance.
Tests to investigate mechanism by which arcR affects planktonic survival.
Measure hydrogen peroxide levels and effects on arcR mutant survival.
Gene expression array carried out on the wild-type and arcR mutant
strains, under high and no arginine conditions, to observe which genes are
affected in expression by the arcR gene or differing arginine conditions.
References
1. Kolenbrander, P.E., Palmer, R.J., Periasamy, S. and Jakubovics, N.S. (2010). ‘Oral multispecies biofilm development and the key role of cell–cell distance', Nat Rev Micro, 8(7), pp. 471-480.
WT
10 µm
arcR mutant
10 µm
Biofilm
Cell
clusters
Figure 3. Cell surface hydrophobicity determined by MATH assay. A
cshA/cshB deletion strain, known to have a lower cell surface
hydrophobicity than wild-type, was used as control alongside the wild-type
and arcR mutant strains. (T-test: * p <0.05).
Figure 1. AFM air imaging of S. gordonii wild-type (WT) growth and arcR mutant
strain growth. Following washing, there is little of the arcR mutant strain left on the
plate.
1
3
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
Biofilmgrowth(A570)
WT arcR mutant
**
Figure 2. Quantitative analysis of the role of arcR in biofilm formation. Biofilms
formed by S. gordonii wild-type (WT) and arcR mutant strains were assessed by
crystal violet staining. (T-test: ** p <0.001).
2
Figure 4. Relative fitness of the wild-type (WT) and arcR mutant strains
as assessed by competition assay. Bacterial cell counts are shown for
each strain over three timepoints – 2h, 24h and 48h. 4A) shows the
planktonic cell counts taken from the media above the biofilm; 4B)
shows the bacterial counts for the biofilms themselves.
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
%Hydrophobicity
*
WT arcR mutant cshA/cshB mutant
Bacterialcellcount(CFU/ml)Bacterialcellcount(CFU/biofilm)
4A
4B
1.00E+07
1.00E+08
1.00E+09
1.00E+10
1
WT arcR deletion
2h 24h 48h 2h 24h 48h
1.00E+06
1.00E+07
1.00E+08
1.00E+09
1
WT arcR deletion
2h 24h 48h 2h 24h 48h
Planktonic
Biofilm