The Effect of Raw Materials on the Properties of Oxidized Cellulose Nanofibers from Bacterial Cellulose

2021 ◽  
Vol 904 ◽  
pp. 309-314
Author(s):  
Supitcha Rungrodnimitchai ◽  
Suphatra Hiranphinyophat
Keyword(s):  
Escherichia Coli ◽  
Bacterial Cellulose ◽  
Raw Materials ◽  
Cellulose Nanofibers ◽  
Oxidized Cellulose ◽  
Negative Bacterium ◽  
Positive Bacterium ◽  
Carboxyl Content ◽  
Gram Negative ◽  
Freeze Dried

In the present study, nanofibers of oxidized cellulose (OC) were prepared from dried bacterial cellulose using a mixture of nitric acid/phosphoric acid and sodium nitrite. Three types of dried bacterial cellulose were used as raw materials. The results revealed that dried sheet bacterial cellulose (DSBC) yielded 86.8% oxidized cellulose with 19.4% carboxyl content, whereas squeeze-dried bacterial cellulose (SDBC) yielded 53.3% OC with 28.6% carboxyl content, and freeze-dried bacterial cellulose (FDBC) yielded 55.6% of OC with 27.6% carboxyl content. The results revealed that OC neutralized with sodium hydroxide from SDBC showed the best swelling property among all types of OC. SDBC indicated the reduction of CFU exceeds 99.99% for gram-negative bacterium Escherichia coli ATCC 25922 and gram-positive bacterium Staphylococcus aureus ATCC 6538.

scholarly journals A study of the antibacterial efficiency and coloration of dyed polyamide and polyester fabrics modified with colloidal Ag nanoparticles

2009 ◽  
Vol 74 (3) ◽  
pp. 349-357 ◽  
Author(s):  
Vesna Ilic ◽  
Zoran Saponjic ◽  
Vesna Vodnik ◽  
Darka Mihailovic ◽  
Petar Jovancic ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Ag Nanoparticles ◽  
Color Change ◽  
Negative Bacterium ◽  
Positive Bacterium ◽  
Gram Negative ◽  
Polyester Fabrics ◽  
Antibacterial Efficiency ◽  
Dyed Fabrics ◽  
Acid Green 25

In this study, the influence of dyeing on the antibacterial efficiency of polyamide and polyester fabrics loaded with colloidal Ag nanoparticles and the influence of the presence of Ag nanoparticles on the color change of dyed fabrics were investigated. Dyes C.I. acid green 25 and C.I. disperse blue 3 were used for dyeing of polyamide fabrics, while dye C.I. disperse violet 8 was used for dyeing of polyester fabrics. The influence of Ag nanoparticles on the color change of polyamide fabrics depends on the dye type, but generally it was lower compared to polyester fabrics. Polyester fabrics exhibited excellent antibacterial efficiency against Gram-positive bacterium Staphylococcus aureus and Gram-negative bacterium Escherichia coli, independent of the order of dyeing and Ag loading. Polyamide fabrics provided a desirable level of antibacterial activity only if the Ag loading was performed after dyeing.

Alkaloids of Anuran Skin: Antimicrobial Function?

2005 ◽  
Vol 60 (11-12) ◽  
pp. 932-937 ◽  
Author(s):  
Cyrus Macfoy ◽  
Douglas Danosus ◽  
Raj Sandit ◽  
Tappey H. Jones ◽  
H. Martin Garraffo ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Skin Infections ◽  
Negative Bacterium ◽  
Positive Bacterium ◽  
Gram Negative ◽  
Poison Frogs ◽  
E Coli ◽  
Antimicrobial Function ◽  
Bacterium Bacillus Subtilis ◽  
Bacterium Bacillus

A variety of alkaloids, most of which occur or are structurally related to alkaloids that occur in skin glands of dendrobatid poison frogs, were assayed for antimicrobial activity against the Gram-positive bacterium Bacillus subtilis, the Gram-negative bacterium Escherichia coli and the fungus Candida albicans. Certain pyrrolidines, piperidines and decahydroquinolines, perhydro-histrionicotoxin, and a synthetic pumiliotoxin were active against B. subtilis. Only 2-n-nonylpiperidine was active against E. coli. One pyrrolidine, two piperidines, two decahydroquinolines, and the synthetic pumiliotoxin were active against the fungus C. albicans. The results suggest that certain of the skin alkaloids of poison frogs, in addition to being noxious to predators, may also benefit the frog through protection against skin infections.

scholarly journals Isolation, Whole-Genome Sequencing, and Annotation of Yimella sp. RIT 621, a Strain That Produces Antibiotic Compounds against Escherichia coli ATCC 25922 and Bacillus subtilis BGSC 168

2019 ◽  
Vol 8 (17) ◽  
Author(s):  
Anutthaman Parthasarathy ◽  
Narayan H. Wong ◽  
Nicolas D. Burns ◽  
Atlantis H. Aziz-Dickerson ◽  
Joyceline Dweh ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Bacillus Subtilis ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Whole Genome ◽  
Negative Bacterium ◽  
Positive Bacterium ◽  
Gram Negative ◽  
Content Type ◽  
Antibiotic Compounds

Here, we report the isolation, identification, whole-genome sequencing, and annotation of the bacterium Yimella sp. strain RIT 621. Concentrated spent medium extract treated with ethyl acetate was found to produce bactericidal compounds against the Gram-positive bacterium Bacillus subtilis BGSC 168 and the Gram-negative bacterium Escherichia coli ATCC 25922.

scholarly journals Influence of biological origin on the tensile properties of cellulose nanopapers

Cellulose ◽  
2021 ◽  
Author(s):  
Katri S. Kontturi ◽  
Koon-Yang Lee ◽  
Mitchell P. Jones ◽  
William W. Sampson ◽  
Alexander Bismarck ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Cell Wall ◽  
Bacterial Cellulose ◽  
Raw Materials ◽  
Cellulose Nanofibers ◽  
Nanofibrillated Cellulose ◽  
Primary Cell Wall ◽  
Biological Origin ◽  
Basic Principles ◽  
Fiber Mats

Abstract Cellulose nanopapers provide diverse, strong and lightweight templates prepared entirely from sustainable raw materials, cellulose nanofibers (CNFs). Yet the strength of CNFs has not been fully capitalized in the resulting nanopapers and the relative influence of CNF strength, their bonding, and biological origin to nanopaper strength are unknown. Here, we show that basic principles from paper physics can be applied to CNF nanopapers to illuminate those relationships. Importantly, it appeared that ~ 200 MPa was the theoretical maximum for nanopapers with random fibril orientation. Furthermore, we demonstrate the contrast in tensile strength for nanopapers prepared from bacterial cellulose (BC) and wood-based nanofibrillated cellulose (NFC). Endemic amorphous polysaccharides (hemicelluloses) in NFC act as matrix in NFC nanopapers, strengthening the bonding between CNFs just like it improves the bonding between CNFs in the primary cell wall of plants. The conclusions apply to all composites containing non-woven fiber mats as reinforcement. Graphic abstract

scholarly journals Three-Dimensional Stable Alginate-Nanocellulose Gels for Biomedical Applications: Towards Tunable Mechanical Properties and Cell Growing

Nanomaterials ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 78 ◽  
Author(s):  
Priscila Siqueira ◽  
Éder Siqueira ◽  
Ana Elza De Lima ◽  
Gilberto Siqueira ◽  
Ana Delia Pinzón-Garcia ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Tissue Engineering ◽  
Wound Healing ◽  
Cellulose Nanocrystals ◽  
Biomedical Applications ◽  
Cellulose Nanofibers ◽  
Oxidized Cellulose ◽  
Freeze Dried ◽  
Alginate Gels

Hydrogels have been studied as promising materials in different biomedical applications such as cell culture in tissue engineering or in wound healing. In this work, we synthesized different nanocellulose-alginate hydrogels containing cellulose nanocrystals, TEMPO-oxidized cellulose nanocrystals (CNCTs), cellulose nanofibers or TEMPO-oxidized cellulose nanofibers (CNFTs). The hydrogels were freeze-dried and named as gels. The nanocelluloses and the gels were characterized by different techniques such as Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and dynamic mechanical thermal analysis (DMTA), while the biological features were characterized by cytotoxicity and cell growth assays. The addition of CNCTs or CNFTs in alginate gels contributed to the formation of porous structure (diameter of pores in the range between 40 and 150 μm). TEMPO-oxidized cellulose nanofibers have proven to play a crucial role in improving the dimensional stability of the samples when compared to the pure alginate gels, mainly after a thermal post-treatment of these gels containing 50 wt % of CNFT, which significantly increased the Ca2+ crosslinking density in the gel structure. The morphological characteristics, the mechanical properties, and the non-cytotoxic behavior of the CNFT-alginate gels improved bioadhesion, growth, and proliferation of the cells onto the gels. Thus, the alginate-nanocellulose gels might find applications in tissue engineering field, as for instance, in tissue repair or wound healing applications.

scholarly journals Does the Antibacterial Activity of Silver Nanoparticles Depend on the Shape of the Nanoparticle? A Study of the Gram-Negative Bacterium Escherichia coli

2007 ◽  
Vol 73 (6) ◽  
pp. 1712-1720 ◽  
Author(s):  
Sukdeb Pal ◽  
Yu Kyung Tak ◽  
Joon Myong Song
Keyword(s):  
Escherichia Coli ◽  
Silver Nanoparticles ◽  
Antibacterial Properties ◽  
Negative Bacterium ◽  
Gram Negative ◽  
Energy Filtering ◽  
Transmission Electron ◽  
Triangular Silver Nanoplates ◽  
Liquid Systems ◽  
Biocidal Property

ABSTRACT In this work we investigated the antibacterial properties of differently shaped silver nanoparticles against the gram-negative bacterium Escherichia coli, both in liquid systems and on agar plates. Energy-filtering transmission electron microscopy images revealed considerable changes in the cell membranes upon treatment, resulting in cell death. Truncated triangular silver nanoplates with a {111} lattice plane as the basal plane displayed the strongest biocidal action, compared with spherical and rod-shaped nanoparticles and with Ag+ (in the form of AgNO3). It is proposed that nanoscale size and the presence of a {111} plane combine to promote this biocidal property. To our knowledge, this is the first comparative study on the bactericidal properties of silver nanoparticles of different shapes, and our results demonstrate that silver nanoparticles undergo a shape-dependent interaction with the gram-negative organism E. coli.

scholarly journals Identification and Biochemical Characterization of a Novel Protein Phosphatase 2C-Like Ser/Thr Phosphatase in Escherichia coli

2018 ◽  
Vol 200 (18) ◽  
Author(s):  
Krithika Rajagopalan ◽  
Elizabeth Nagle ◽  
Jonathan Dworkin
Keyword(s):  
Escherichia Coli ◽  
Protein Phosphatase ◽  
Biochemical Characterization ◽  
Regulatory Protein ◽  
Negative Bacterium ◽  
Gram Negative ◽  
Content Type ◽  
E Coli ◽  
Novel Protein

Regulatory protein phosphorylation is a conserved mechanism of signaling in all biological systems. Recent phosphoproteomic analyses of phylogenetically diverse bacteria, including the model Gram-negative bacteriumEscherichia coli, demonstrate that many proteins are phosphorylated on serine or threonine residues. In contrast to phosphorylation on histidine or aspartate residues, phosphorylation of serine and threonine residues is stable and requires the action of a partner Ser/Thr phosphatase to remove the modification. Although a number of Ser/Thr kinases have been reported inE. coli, no partner Ser/Thr phosphatases have been identified. Here, we biochemically characterize a novel Ser/Thr phosphatase that acts to dephosphorylate a Ser/Thr kinase that is encoded in the same operon.

scholarly journals Complete Genome Sequence of Escherichia coli Podophage Penshu1

2019 ◽  
Vol 8 (38) ◽  
Author(s):  
Douglas Pechacek ◽  
Myung Hwangbo ◽  
Russell Moreland ◽  
Mei Liu ◽  
Jolene Ramsey
Keyword(s):  
Escherichia Coli ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Coliform Bacteria ◽  
Negative Bacterium ◽  
Gram Negative ◽  
Content Type ◽  
E Coli ◽  
Protein Encoding ◽  
Encoding Genes

Escherichia coli 4s is a Gram-negative bacterium found in the equine intestinal ecosystem alongside diverse other coliform bacteria and bacteriophages. This announcement describes the complete genome of the T7-like E. coli 4s podophage Penshu1. From its 39,263-bp genome, 54 protein-encoding genes and a 179-bp terminal repeat were predicted.

scholarly journals Complete Genome Sequence of Escherichia coli Siphophage Snoke

2019 ◽  
Vol 8 (40) ◽  
Author(s):  
James E. Corban ◽  
Jacob Gramer ◽  
Russell Moreland ◽  
Mei Liu ◽  
Jolene Ramsey
Keyword(s):  
Escherichia Coli ◽  
Genome Sequence ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Negative Bacterium ◽  
Protein Coding ◽  
Gram Negative ◽  
Content Type ◽  
E Coli ◽  
Protein Coding Genes

Escherichia coli is a Gram-negative bacterium often found in animal intestinal tracts. Here, we present the genome of the Guernseyvirinae-like E. coli 4s siphophage Snoke. The 44.4-kb genome contains 81 protein-coding genes, for which 33 functions were predicted. The capsid morphogenesis gene in Snoke contains a large intein.

scholarly journals Structural and Functional Analysis of PGRP-LC Indicates Exclusive Dap-Type PGN Binding in Bumblebees

2020 ◽  
Vol 21 (7) ◽  
pp. 2441 ◽  
Author(s):  
Yanjie Liu ◽  
Nanhui Ye ◽  
Minming Chen ◽  
Huiyue Zhao ◽  
Jiandong An
Keyword(s):  
Escherichia Coli ◽  
Functional Analysis ◽  
Immune Response ◽  
Hydrogen Bond ◽  
Negative Bacterium ◽  
Anchor Residue ◽  
Gram Negative ◽  
E Coli ◽  
Imd Pathway ◽  
Immune Pathways

Peptidoglycan recognition proteins (PGRPs) play an important role in the defense against invading microbes via the recognition of the immunogenic substance peptidoglycan (PGN). Bees possess fewer PGRPs than Drosophila melanogaster and Anopheles gambiae but retain two important immune pathways, the Toll pathway and the Imd pathway, which can be triggered by the recognition of Dap-type PGN by PGRP-LCx with the assistance of PGRP-LCa in Drosophila. There are three isoforms of PGRP-LC including PGRP-LCx, PGRP-LCa and PGRP-LCy in Drosophila. Our previous study showed that a single PGRP-LC exists in bumblebees. In this present study, we prove that the bumblebee Bombus lantschouensis PGRP-LC (Bl-PGRP-LC) can respond to an infection with Gram-negative bacterium Escherichia coli through binding to the Dap-type PGNs directly, and that E. coli infection induces the quick and strong upregulation of PGRP-LC, abaecin and defensin. Moreover, the Bl-PGRP-LC exhibits a very strong affinity for the Dap-type PGN, much stronger than the affinity exhibited by the PGRP-LC from the more eusocial honeybee Apis mellifera (Am-PGRP-LC). In addition, mutagenesis experiments showed that the residue His390 is the anchor residue for the binding to the Dap-type PGN and forms a hydrogen bond with MurNAc rather than meso-Dap, which interacts with the anchor residue Arg413 of PGRP-LCx in Drosophila. Therefore, bumblebee PGRP-LC possesses exclusive characteristics for the immune response among insect PGRPs.

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