scholarly journals Effect of Pretreatments on the Enzymatic Hydrolysis of High-Yield Bamboo Chemo-Mechanical Pulp by Changing the Surface Lignin Content

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 787
Author(s):  
Lianxin Luo ◽  
Xiaojun Yuan ◽  
Sheng Zhang ◽  
Xuchong Wang ◽  
Mingfu Li ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Enzymatic Hydrolysis ◽  
Laser Scanning ◽  
Lignin Content ◽  
Value Added ◽  
Laser Scanning Microscopy ◽  
High Yield ◽  
Confocal Laser ◽  
Mechanical Pulp ◽  
Hydrolysis Of

Hydrogen peroxide chemo-mechanical pulp (APMP), sulfonated chemo-mechanical pulp (SCMP), and chemical thermomechanical pulp (CTMP) were used as raw materials to explore the effects of hydrogen peroxide (HP), Fenton pretreatment (FP), and ethanol pretreatment (EP) on the enzymatic hydrolysis of high-yield bamboo mechanical pulp (HBMP). The surface lignin distribution and contents of different HBMPs were determined using confocal laser scanning microscopy (CLSM) and X-ray photoelectron spectroscopy (XPS). The correlation between the surface lignin and the enzymatic hydrolysis of HBMP was also investigated. The residue of enzymatic hydrolysis was used to adsorb methylene blue (MB). The results showed that the cracks and fine fibers on the surface of APMP, SCMP, and CTMP increased after FP, when compared to HP and EP. The total removal content of hemicellulose and lignin in SCMP after FP was higher than with HP and EP. Compared to SCMP, the crystallinity increased by 15.4%, and the surface lignin content of Fenton-pretreated SCMP decreased by 11.7%. The enzymatic hydrolysis efficiency of HBMP after FP was higher than with HP and EP. The highest enzymatic hydrolysis of Fenton-pretreated SCMP was 49.5%, which was higher than the enzymatic hydrolysis of Fenton-pretreated APMP and CTMP. The removal rate of MB reached 94.7% after the adsorption of the enzymatic hydrolysis residue of SCMP. This work provides an effective approach for a high value-added utilization of high-yield bamboo pulp.

Interspecies Interactions in Dual-Species Biofilms Formed by Psychrotrophic Bacteria and the Tolerance of Sessile Communities to Disinfectants

2020 ◽  
Vol 83 (6) ◽  
pp. 951-958 ◽  
Author(s):  
LEI YUAN ◽  
NI WANG ◽  
FAIZAN A. SADIQ ◽  
GUOQING HE
Keyword(s):  
Hydrogen Peroxide ◽  
Sodium Hypochlorite ◽  
Peracetic Acid ◽  
Laser Scanning ◽  
Structural Changes ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Interspecies Interactions ◽  
Mixed Species ◽  
Psychrotrophic Bacteria

ABSTRACT Biofilms on the surface of food processing equipment act as potential reservoirs of microbial contamination. Bacterial interactions are believed to play key roles in both biofilm formation and antimicrobial tolerance. In this study, Aeromonas hydrophila, Chryseobacterium oncorhynchi, and Pseudomonas libanensis, which were previously isolated from Chinese raw milk samples, were selected to establish two dual-species biofilm models (P. libanensis plus A. hydrophila and P. libanensis plus C. oncorhynchi) on stainless steel at 7°C. Subsequently, three disinfectants, hydrogen peroxide (100 ppm), peracetic acid (100 ppm), and sodium hypochlorite (100 ppm), were used to treat the developed sessile communities for 10 min. Structural changes after exposure to disinfectants were analyzed with confocal laser scanning microscopy. The cell numbers of both A. hydrophila and C. oncorhynchi recovered from surfaces increased when grown as dual species biofilms with P. libanensis. Dual-species biofilms were more tolerant of disinfectants than were each single-species biofilm. Peracetic acid was the most effective disinfectant for removing biofilms, followed by hydrogen peroxide and sodium hypochlorite. The results expand the knowledge of mixed-species biofilms formed by psychrotrophic bacteria and will be helpful for developing effective strategies to eliminate bacterial mixed-species biofilms. HIGHLIGHTS

Layer-by-Layer Engineered Microreactors for Bio-Polymerization of 4-(2-aminoethyl) phenol hydrochloride

2003 ◽  
Vol 782 ◽  
Author(s):  
R. Ghan ◽  
T. Shutava ◽  
A. Patel ◽  
V. John ◽  
Y. Lvov
Keyword(s):  
Hydrogen Peroxide ◽  
Molecular Weight ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Polymerization Reaction ◽  
Confocal Laser ◽  
Layer By Layer ◽  
Polymeric Form ◽  
Characterization Methods ◽  
Concentrated Solution

ABSTRACTThis study presents the results of polymerization of phenol to yield fluorescent polymer encapsulated within shells fabricated via layer-by-layer (L-b-L) assembly. Hollow polyelectrolyte microcapsules (shells) were prepared using weakly cross-linked melamine formaldehyde (MF) particles. Dissolution of the MF cores was achieved by changing the pH of the solution. Horseradish peroxidase (HRP), the catalyzing enzyme, was loaded in these capsules by taking advantage of the “open/close” mechanism of the capsules by altering the pH. The empty shells were then suspended in a concentrated solution of monomer. Since the monomer is a low molecular weight species, it freely permeates through the polyion wall into the shells. Addition of aliquots of hydrogen peroxide initiated the polymerization reaction and the polymer formed from the ensuing reaction was confined in the shells due to its high molecular weight. The model used for demonstrating this synthesis is polymerization of 4-(2-aminoethyl) phenol hydrochloride commonly known as tyramine hydrochloride to its corresponding polymeric form by reacting it with hydrogen peroxide. Fluorescence spectrometry (FS), confocal laser scanning microscopy (CLSM), and atomic force microscopy (AFM) were the characterization methods employed to confirm polymerization in situ shells.

scholarly journals Effect of bleaching on sound enamel and with early artificial caries lesions using confocal laser microscopy

2012 ◽  
Vol 23 (2) ◽  
pp. 110-115 ◽  
Author(s):  
Sandrine Bittencourt Berger ◽  
Sabrina Pavan ◽  
Paulo Henrique dos Santos ◽  
Marcelo Giannini ◽  
Ana Karina B. Bedran-Russo
Keyword(s):  
Hydrogen Peroxide ◽  
Calcium Phosphate ◽  
Fluorescence Intensity ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Significant Difference ◽  
Ph Cycling ◽  
Bovine Enamel ◽  
Caries Lesions

The aim of this study was to evaluate effect of bleaching agents on sound enamel (SE) and enamel with early artificial caries lesions (CL) using confocal laser scanning microscopy (CLSM). Eighty blocks (4 x 5 x 5 mm) of bovine enamel were used and half of them were submitted to a pH cycling model to induce CL. Eight experimental groups were obtained from the treatments and mineralization level of the enamel (SE or CL) (n=10). SE groups: G1 - unbleached (control); G2 - 4% hydrogen peroxide (4 HP); G3 - 4 HP containing 0.05% Ca (Ca); G4 - 7.5% hydrogen peroxide (7.5 HP) containing amorphous calcium phosphate (ACP). CL groups: G5 - unbleached; G6 - 4 HP; G7 - 4 HP containing Ca; G8 - 7.5 HP ACP. G2, G3, G6, G7 were treated with the bleaching agents for 8 h/day during 14 days, while G4 and G8 were exposed to the bleaching agents for 30 min twice a day during 14 days. The enamel blocks were stained with 0.1 mM rhodamine B solution and the demineralization was quantified using fluorescence intensity detected by CLSM. Data were analyzed using ANOVA and Fisher’s tests (α=0.05). For the SE groups, the bleaching treatments increased significantly the demineralization area when compared with the unbleached group. In the CL groups, no statistically significant difference was observed (p>0.05).The addition of ACP or Ca in the composition of the whitening products did not overcome the effects caused by bleaching treatments on SE and neither was able to promote remineralization of CL.

scholarly journals Ferulated Pectins and Ferulated Arabinoxylans Mixed Gel for Saccharomyces boulardii Entrapment in Electrosprayed Microbeads

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2478
Author(s):  
Federico Ohlmaier-Delgadillo ◽  
Elizabeth Carvajal-Millan ◽  
Yolanda L. López-Franco ◽  
María A. Islas-Osuna ◽  
Valérie Micard ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Cell Immobilization ◽  
Value Added ◽  
Saccharomyces Boulardii ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Cross Linking ◽  
Low Degree ◽  
Before And After ◽  
Probiotic Yeast

Ferulated polysaccharides such as pectin and arabinoxylan form covalent gels which are attractive for drug delivery or cell immobilization. Saccharomyces boulardii is a probiotic yeast known for providing humans with health benefits; however, its application is limited by viability loss under environmental stress. In this study, ferulated pectin from sugar beet solid waste (SBWP) and ferulated arabinoxylan from maize bioethanol waste (AX) were used to form a covalent mixed gel, which was in turn used to entrap S. boulardii (2.08 × 108 cells/mL) in microbeads using electrospray. SBWP presented a low degree of esterification (30%), which allowed gelation through Ca2+, making it possible to reduce microbead aggregation and coalescence by curing the particles in a 2% CaCl2 cross-linking solution. SBWP/AX and SBWP/AX+ S. boulardii microbeads presented a diameter of 214 and 344 µm, respectively, and a covalent cross-linking content (dimers di-FA and trimer tri-FA of ferulic acid) of 1.15 mg/g polysaccharide. The 8-5′, 8-O-4′and 5-5′di-FA isomers proportions were 79%, 18%, and 3%, respectively. Confocal laser scanning microscopy images of propidium iodide-stained yeasts confirmed cell viability before and after microbeads preparation by electrospray. SBWP/AX capability to entrap S. boulardii would represent an alternative for probiotic immobilization in tailored biomaterials and an opportunity for sustainable waste upcycling to value-added products.

scholarly journals Endoplasmic reticulum resident proteins of normal human dermal fibroblasts are the major targets for oxidative stress induced by hydrogen peroxide

2002 ◽  
Vol 366 (3) ◽  
pp. 825-830 ◽  
Author(s):  
Dennis van der VLIES ◽  
Eward H.W. PAP ◽  
Jan Andries POST ◽  
Julio E. CELIS ◽  
Karel W.A. WIRTZ
Keyword(s):  
Hydrogen Peroxide ◽  
Endoplasmic Reticulum ◽  
Laser Scanning ◽  
Dermal Fibroblasts ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Human Dermal Fibroblasts ◽  
Normal Human ◽  
Covalently Linked ◽  
Normal Human Dermal Fibroblasts

The membrane-permeable fluorescein-labelled tyramine conjugate (acetylTyrFluo) was used to identify the proteins of normal human dermal fibroblasts most susceptible to oxidation by hydrogen peroxide [Van der Vlies, Wirtz and Pap (2001) Biochemistry 40, 7783—7788]. By exposing the cells to H2O2 (0.1mM for 10min), TyrFluo was covalently linked to target proteins. TyrFluo-labelled and [35S]Met-labelled cell lysates were mixed and subjected to two-dimensional PAGE. After Western blotting the 35S-labelled proteins were visualized by autoradiography and the TyrFluo-labelled proteins by using anti-fluorescein antibody. The TyrFluo-labelled proteins were matched with the 35S-labelled proteins and identified by comparison with our mastermap of proteins. Protein disulphide isomerase (PDI), IgG-binding protein (BiP), calnexin, endoplasmin and glucose-regulated protein 58 (endoplasmic reticulum protein 57/GRP58) were identified as targets of oxidation. All these proteins reside in the endoplasmic reticulum and are part of the protein folding machinery. In agreement, confocal laser scanning microscopy showed co-localization of TyrFluo-labelled proteins and the KDEL receptor ERD-2, a marker for the endoplasmic reticulum.

scholarly journals Genetic and Physiological Effects of Noncoherent Visible Light Combined with Hydrogen Peroxide on Streptococcus mutans in Biofilm

2008 ◽  
Vol 52 (7) ◽  
pp. 2626-2631 ◽  
Author(s):  
Doron Steinberg ◽  
Daniel Moreinos ◽  
John Featherstone ◽  
Moshe Shemesh ◽  
Osnat Feuerstein
Keyword(s):  
Gene Expression ◽  
Hydrogen Peroxide ◽  
Visible Light ◽  
Streptococcus Mutans ◽  
Laser Scanning ◽  
Antibacterial Effect ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Planktonic Bacteria ◽  
Deep Layers

ABSTRACT Oral biofilms are associated with the most common infections of the oral cavity. Bacteria embedded in the biofilms are less sensitive to antibacterial agents than planktonic bacteria are. Recently, an antibacterial synergic effect of noncoherent blue light and hydrogen peroxide (H2O2) on planktonic Streptococcus mutans was demonstrated. In this study, we tested the effect of a combination of light and H2O2 on the vitality and gene expression of S. mutans embedded in biofilm. Biofilms of S. mutans were exposed to visible light (wavelengths, 400 to 500 nm) for 30 or 60 s (equivalent to 34 or 68 J/cm2) in the presence of 3 to 300 mM H2O2. The antibacterial effect was assessed by microbial counts of each treated sample compared with that of the control. The effect of light combined with H2O2 on the different layers of the biofilm was evaluated by confocal laser scanning microscopy. Gene expression was determined by real-time reverse transcription-PCR. Our results show that noncoherent light, in combination with H2O2, has a synergistic antibacterial effect through all of the layers of the biofilm. Furthermore, this treatment was more effective against bacteria in biofilm than against planktonic bacteria. The combined light and H2O2 treatment up-regulated the expression of several genes such as gtfB, brp, smu630, and comDE but did not affect relA and ftf. The ability of noncoherent visible light in combination with H2O2 to affect bacteria in deep layers of the biofilm suggests that this treatment may be applied in biofilm-related diseases as a minimally invasive antibacterial procedure.

scholarly journals Hydrogen Peroxide-Generating Electrochemical Scaffold Activity against Trispecies Biofilms

2020 ◽  
Vol 64 (4) ◽  
Author(s):  
Yash S. Raval ◽  
Abdelrhman Mohamed ◽  
James Song ◽  
Kerryl E. Greenwood-Quaintance ◽  
Haluk Beyenal ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Laser Scanning ◽  
Matrix Protein ◽  
Multidrug Resistant ◽  
Laser Scanning Microscopy ◽  
Time Dependent ◽  
Confocal Laser ◽  
Antibiofilm Activity ◽  
Content Type ◽  
Wound Biofilms

ABSTRACT The antibiofilm activity of a hydrogen peroxide-generating electrochemical scaffold (e-scaffold) was determined against mono- and trispecies biofilms of methicillin-resistant Staphylococcus aureus, multidrug-resistant Pseudomonas aeruginosa, and Candida albicans. Significant time-dependent decreases were found in the overall CFU of biofilms of all three monospecies and the trispecies forms. Confocal laser scanning microscopy showed dramatic reductions in fluorescence intensities of biofilm matrix protein and polysaccharide components of e-scaffold-treated biofilms. The described e-scaffold has potential as a novel antibiotic-free strategy for treating wound biofilms.

In vitro phototoxicity and dark-toxicity of a novel synthesized pyropheophorbide-a-paclitaxel conjugate against cancer cell lines

2012 ◽  
Vol 16 (09) ◽  
pp. 1006-1014 ◽  
Author(s):  
Gantumur Battogtokh ◽  
Hai-Bo Liu ◽  
Su-Mi Bae ◽  
Pankaj K. Chaturvedi ◽  
Yong-Wan Kim ◽  
...  
Keyword(s):  
Cell Lines ◽  
Cancer Cell ◽  
Laser Scanning ◽  
Human Cancer ◽  
Cancer Cell Lines ◽  
Laser Scanning Microscopy ◽  
High Yield ◽  
Confocal Laser ◽  
Resonance Spectroscopy ◽  
Pyropheophorbide A

Synthesis of pyropheophorbide-a-paclitaxel (PPa-PTX) conjugate was performed in high yield with the aim of searching for an optimal agent for cancer treatment. After synthesis, the conjugate was confirmed to be linked through an ester bond at the 2′ position of the paclitaxel moiety using multi-nuclear magnetic resonance spectroscopy. Phototoxicity of PPa and PPa-PTX conjugate, as well as PTX, was evaluated with three human cancer cell lines (HeLa, CaSki and TC-1). The new conjugate at 0.01–0.06 μM displayed 20–40% higher phototoxicity in HeLa and CaSki cell lines than free PPa and PTX. Furthermore, cellular uptake of these bio-molecules was examined by confocal laser scanning microscopy. Although PPa-PTX showed a delayed uptake compared to PPa, it penetrated completely into cells within 24 h incubation.

scholarly journals Effects of Cold-Light Bleaching on Enamel Surface and Adhesion of Streptococcus mutans

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Bo Zhang ◽  
Sibei Huo ◽  
Shiyu Liu ◽  
Ling Zou ◽  
Lei Cheng ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Streptococcus Mutans ◽  
Laser Scanning ◽  
Bacterial Species ◽  
Laser Scanning Microscopy ◽  
Enamel Surface ◽  
Tooth Bleaching ◽  
Confocal Laser ◽  
Tooth Structure ◽  
Force Microscopy

Tooth bleaching is becoming increasingly popular among patients with tooth staining, but the safety of bleaching agents on tooth structure has been questioned. Primarily thriving on the biofilm formation on enamel surface, Streptococcus mutans has been recognized as a major cariogenic bacterial species. The present study is aimed at investigating how cold-light bleaching would change enamel roughness and adhesion of Streptococcus mutans. Human premolars were divided into 72 enamel slices and allocated into 3 groups: (1) control, (2) cold-light bleaching with 35% hydrogen peroxide (Beyond™), and (3) 35% hydrogen peroxide (Beyond™) alone. Biofilms of Streptococcus mutans were cultivated on enamel slices in 5% CO2 ( v / v ) at 37°C for 1 day or 3 days. Enamel surfaces and biofilms were observed using scanning electron microscope (SEM). Atomic force microscopy (AFM) was applied to quantify the roughness of enamel surface, and the amounts of biofilms were measured by optical density of scattered biofilm and confocal laser scanning microscopy (CLSM). Cold-light bleaching significantly increased ( p < 0.05 ) surface roughness of enamel compared to controls, but significantly inhibited ( p < 0.05 ) adhesion of Streptococcus mutans on enamel in the bacterial cultures of both 1 day and 3 days. In conclusion, cold-light bleaching could roughen enamel surface but inhibit Streptococcus mutans adhesion at the preliminary stage after the bleaching treatment.

3-D imaging of cells using a confocal laser scanning microscope and digital image processing

1988 ◽  
Vol 46 ◽  
pp. 96-97
Author(s):  
Thomas M. Jovin ◽  
Michel Robert-Nicoud ◽  
Donna J. Arndt-Jovin ◽  
Thorsten Schormann
Keyword(s):  
Laser Scanning ◽  
Confocal Laser Scanning Microscope ◽  
Laser Scanning Microscopy ◽  
Confocal Laser Scanning ◽  
Confocal Laser ◽  
Scanning Microscope ◽  
Laser Scanning Microscope ◽  
Biochemical Processes ◽  
Adjacent Structures

Light microscopic techniques for visualizing biomolecules and biochemical processes in situ have become indispensable in studies concerning the structural organization of supramolecular assemblies in cells and of processes during the cell cycle, transformation, differentiation, and development. Confocal laser scanning microscopy offers a number of advantages for the in situ localization and quantitation of fluorescence labeled targets and probes: (i) rejection of interfering signals emanating from out-of-focus and adjacent structures, allowing the “optical sectioning” of the specimen and 3-D reconstruction without time consuming deconvolution; (ii) increased spatial resolution; (iii) electronic control of contrast and magnification; (iv) simultanous imaging of the specimen by optical phenomena based on incident, scattered, emitted, and transmitted light; and (v) simultanous use of different fluorescent probes and types of detectors.We currently use a confocal laser scanning microscope CLSM (Zeiss, Oberkochen) equipped with 3-laser excitation (u.v - visible) and confocal optics in the fluorescence mode, as well as a computer-controlled X-Y-Z scanning stage with 0.1 μ resolution.

Sign in / Sign up

Export Citation Format

Share Document