Advances in understanding bioactivity of chitosan and chitosan oligomers against selected wood-inhabiting fungi

Holzforschung ◽  
2005 ◽  
Vol 59 (5) ◽  
pp. 559-567 ◽  
Author(s):  
Kirk M. Torr ◽  
Colleen Chittenden ◽  
Robert A. Franich ◽  
Bernhard Kreber

Abstract Nitrous acid deaminative depolymerisation was used to prepare three chitosan oligomer (CO) mixtures from high-molecular weight chitosan. These mixtures of chitosan oligosaccharides were analysed by electrospray ionisation mass spectroscopy, potentiometric titration and gel permeation chromatography. A method based on potentiometric titration of the amino groups of the oligomers gave an average degree of polymerisation (DP) for the three preparations of 5 (CODP5), 9 (CODP9) and 14 (CODP14). Chitosan acetate and the chitosan oligomer mixtures were assayed against Leptographium procerum, Sphaeropsis sapinea and Trichoderma harzianum on nutrient media. Leptographium procerum and S. sapinea growth was prevented by chitosan acetate and chitosan oligomers at concentrations of 0.3–0.4% (w/v), whereas T. harzianum was able to overcome the fungistatic action of these compounds. The oligomer preparation CODP14 exhibited superior specific activity to both CODP5 and chitosan acetate, suggesting an optimum molecular weight for bioactivity. All oligomer preparations were more effective at pH 4 than at pH 6. This result, in combination with the inactivity of N-acetylated CODP14, indicated that amino group protonation was an important factor for fungistatic activity. The CODP14 preparation was reduced with sodium borohydride and fractionated by alkali precipitation and ion exchange chromatography. Bioassays of these fractions pointed towards DP and degree of deacetylation (DD) as key factors in chito-oligosaccharide bioactivity. Conversely, the terminal aldehyde groups generated by depolymerisation did not contribute to the activity observed.

1987 ◽  
Vol 65 (1) ◽  
pp. 27-34 ◽  
Author(s):  
Scot R. Kimball ◽  
William L. Meyer

Multiple forms of ribonuclease II (EC 3.1.27.5) have been resolved from extracts of crude fractions of mouse liver by ion-exchange chromatography on phosphocellulose and gel permeation chromatography. The forms are designated 6S, 6L, 5S, 5L, 4S, 4L, 3S, 3L, 2, and 1 in increasing order of apparent cationic character. The forms fall into two series of apparent molecular weight. The small series increases from molecular weight equal to 9000 for form 1 to 14 000 for form 6S. The large series increases from molecular weight equal to 22 000 for form 2 to 44 000 for form 6L. All forms have pH–activity profiles with maxima near pH 7. Activity falls to no less than 30% of this maximum at pHs 5 and 8.5. Relative to the other forms, form 1 has a higher ratio of activity in the alkaline compared with acid pH range. Form 1 is found in the cytosolic, "light" particle, and "heavy" particle fractions. The other forms are largely restricted to the heavy particle fraction. In this fraction the proportion of total activity attributable to each form generally decreases in order from form 1 down to form 6. The results are accommodated by models in which one or more gene products give rise to multiple forms of ribonuclease II by processes involving dimerization and glycosylation.


2004 ◽  
Vol 69 (1) ◽  
pp. 9-16 ◽  
Author(s):  
Svetlana Seatovic ◽  
Ljubinka Gligic ◽  
Zeljka Radulovic ◽  
Ratko Jankov

Superoxide dismutase (SOD; EC 1.15.1.1), a high molecular weight component of the antioxidant defense system, provided promising results in the treatment of oxidative damage. Thermothrix sp., isolated from thermal spa water in Serbia, showed high superoxide dismutase activity. The SOD, from cell free extract, was purified to homogenity by ammonium sulfate precipitation, Sephadex G 75 gel filtration chromatography and QAE Sephadex ion exchange chromatography. The specific activity of the purified enzyme was 9191 U/mg. The purified enzyme was analyzed and partially characterized. SOD was localized in polyacrylamide gel by activity staining, based on the reduction of nitroblue tetrazolium (NBT) by superoxide. The enzyme molecular weight determined by gel chromatography is 37 kD. According to SDS PAGE it is composed of two subunits of equal size, joined by noncovalent interactions. The isoelectric point, assessed by isoelectric focusing is 5.3. The optimum pH for enzyme activity was in the range of 8 to 10. The optimum temperature for SOD activity was 60 ?C. After one hour of incubation at 40, 50 and 60 ?C the SOD activity increases, but at 80 ?C, the SOD is denaturated. After 24 hours of incubation at 25 ?C SO Dactivity only slightly decreases.


2019 ◽  
Vol 20 (14) ◽  
pp. 3553 ◽  
Author(s):  
Meibian Hu ◽  
Yujie Liu ◽  
Li Wang ◽  
Jiaolong Wang ◽  
Lin Li ◽  
...  

Pinelliae Rhizoma Praeparatum cum Alumine (PRPCA) is an important traditional processed herbal medicine mainly used for treating phlegm in China for more than 2000 years. In our previous studies, extraction optimization, characterization, and bioactivities of total polysaccharides from PRPCA were investigated. In this study, further purification of these polysaccharides was performed. Two polysaccharides named neutral fraction of total polysaccharides-II (TPN-II) and acidic fraction of total polysaccharides-II (TPA-II) were obtained by gradient ion-exchange chromatography followed by gel-permeation chromatography. Results of scanning electron microscopy (SEM) analysis in the present study showed that TPN-II had a tight structure with a rough and uneven surface, while TPA-II had a relative homogeneous surface and a loose structure. Further studies indicated that TPN-II was a homosaccharide mainly composed by glucose with a molecular weight of 8.0 kDa. TPA-II was mainly composed of mannose, rhamnose, glucuronic acid, galacturonic acid, glucose, galactose and arabinose in a molar ratio of 2.1, 2.3, 1.7, 10.6, 2.6, 14.2, and 2.5, with a molecular weight of 1250 kDa. The nuclear magnetic resonance (NMR) results indicated that α and β form glycoside bonds existed in TPN-II and TPA-II, and TPN-II was composed of α-glucopyranose. In addition, both purified polysaccharides have significant anti-inflammatory effects on mucus secretion of human airway epithelial NCI-H292 cells without cytotoxicity. Compared with TPN-II, TPA-II exhibited more significant anti-inflammatory effects on lipopolysaccharide (LPS)-induced airway inflammation by regulating levels of interleukin-4 (IL-4) and interferon-γ (IFN-γ) and inhibiting mucus secretion. The results suggest that polysaccharides from PRPCA could be explored as therapeutic agents in treating inflammation and over secretion of mucus in asthma.


1989 ◽  
Vol 262 (2) ◽  
pp. 409-416 ◽  
Author(s):  
G A Saravani ◽  
D A Cowan ◽  
R M Daniel ◽  
H W Morgan

An extracellular alkaline serine proteinase from Thermus strain ToK3 was isolated and purified to homogeneity by (NH4)2SO4 precipitation followed by ion-exchange chromatography on DEAE-cellulose and QAE-Sephadex, affinity chromatography on N alpha-benzyloxycarbonyl-D-phenylalanyl-triethylenetetraminyl-Sepha rose 4B and gel-filtration chromatography on Sephadex G-75. The purified enzyme had a pI of 8.9 and an Mr determined by gel-permeation chromatography of 25,000. The specific activity was about 37,700 proteolytic units/mg with casein as substrate, and the pH optimum was 9.5. Proteolytic activity was inhibited by low concentrations of di-isopropyl phosphorofluoridate and phenylmethanesulphonyl fluoride, but was unaffected by EDTA, EGTA, o-phenanthroline, N-ethyl-5-phenylisoxazolium-3′-sulphonate, N alpha-p-tosyl-L-phenylalanylchloromethane, N alpha-p-tosyl-L-lysylchloromethane, trypsin inhibitors and pepstatin A. The enzyme contained approx. 10% carbohydrate and four disulphide bonds. No Ca2+, Zn2+ or free thiol groups were detected. It hydrolysed several native and dye-linked proteins and synthetic chromogenic peptides and esters. The enzyme was very thermostable (half-life values were 840 min at 80 degrees C, 45 min at 90 degrees C and 5 min at 100 degrees C). The enzyme was unstable at low ionic strength: after 60 min at 75 degrees C in 0.1 M-Tris/acetate buffer, pH 8, only 20% activity remained, compared with no loss in 0.1 M-Tris/acetate buffer, pH 8, containing 0.4 M-NaCl.


Parasitology ◽  
1998 ◽  
Vol 117 (6) ◽  
pp. 555-562 ◽  
Author(s):  
L. PIACENZA ◽  
R. RADI ◽  
F. GOÑI ◽  
C. CARMONA

The levels of superoxide dismutase (SOD) were determined in detergent-soluble, somatic and excretion–secretion (E–S) preparations from adult Fasciola hepatica using the xanthine oxidase system and visualized in substrate gels. Compared to detergent-soluble and somatic extracts, E–S products showed the highest SOD activity (88 ·5 U/mg), indicating active release to the medium in which parasites were maintained. SOD specific activity was also detected at high levels in E–S products from 3-week-old and 5-week-old immature migrating flukes (25 and 143 U/mg, respectively). In all preparations except for the somatic extract, the activity was characterized as cyanide-sensitive CuZn SOD. Differences in SOD isoenzyme profiles between the extracts were observed in native polyacrylamide gel electrophoresis: the somatic and detergent-soluble extracts exhibited 1 band of activity while the E–S products from immature and adults flukes contained 2 and 3 migrating bands, respectively. SOD was purified from the detergent-soluble extract and E–S products of adult worms by a combination of ultrafiltration, gel filtration on Sephacryl S-200 HR and ion-exchange chromatography on QAE Sephadex A-50. The SOD from detergent-soluble extract showed, by SDS–PAGE analysis, 1 band of 16 kDa apparent molecular weight. The SOD from E–S products showed 2 bands of 16 and 60 kDa apparent molecular weight. N-terminal sequence analysis of the 16 kDa band from the detergent-soluble preparation showed some similarity with Schistosoma mansoni cytoplasmic SOD. These enzymes may have a potential role in the evasion of the oxidative burst killing mechanism by immune cells.


1985 ◽  
Vol 161 (3) ◽  
pp. 490-502 ◽  
Author(s):  
S R Kronheim ◽  
C J March ◽  
S K Erb ◽  
P J Conlon ◽  
D Y Mochizuki ◽  
...  

We have purified human interleukin 1 (IL-1) to homogeneity by a simplified procedure that results in excellent yields of pure material that retains a high level of biological activity. IL-1, secreted by human peripheral blood macrophages that have been stimulated with Staphylococcus aureus, was purified by ion exchange chromatography and affinity chromatography on Procion Red agarose. The pure protein has a specific activity of 3.2 X 10(8) U/mg in the thymocyte mitogenesis assay, and is pyrogenic. No molecular weight heterogeneity was observed, in contrast to findings for mouse IL-1 and earlier reports of human IL-1. Purified IL-1, as analyzed by two-dimensional electrophoresis/electrofocusing gels, exhibited a series of charged species with isoelectric points ranging from 6.0 to 4.9, all with a molecular weight of approximately 17,500. Amino acid analysis indicated an abundance of acidic residues, in agreement with the low isoelectric points. There is little or no cysteine in the molecule. No evidence was found for the presence of carbohydrate moieties. The overall yield for this procedure was approximately 31% of the activity contained in the initial culture supernatant.


2021 ◽  
Vol 28 ◽  
Author(s):  
Vaithiyanathan Suganthi ◽  
Selvarajan Ethiraj ◽  
Nivetha Anbalagan ◽  
Jannatul Firdous Siddique ◽  
Mohanasrinivasan Vaithilingam

Aims: To encapsulate a purified bacteriocin into nanovesicles and check its antibacterial effect Background: Although the use of nano-encapsulated bacteriocins in food matrices is poorly reported, encapsulated nisin can reduce L. monocytogenes counts in whole and skimmed milk and soft cheese. Objective: The present study deals with the extraction and purification of a bacteriocin from an isolated strain Pediococcus pentosaceus KC692718. A comparative study of the effect of free pediocin and liposome-encapsulated pediocin against Listeria sp. was performed. Methods: The purification of the extracted cell-free supernatant was subjected to ammonium sulphate precipitation, cation exchange chromatography, followed by gel permeation chromatography. The bacteriocin activity and protein concentration were determined using Lowry’s method. The characterization of the pure pediocin was also done. Liposome-like nanovesicle was constructed, and the stability of the liposome-encapsulated pediocin was checked. Finally, the antibacterial effect of the free pediocin, liosome, and liposome-encapsulated pediocin was comparatively studied simultaneously. Results: The pediocin of 3.6 kDa was purified with a specific activity of 898.8 AU/mg. It remained stable at the pH range of 2.0 - 8.0 for one month when stored at -20°C, while it remained moderately stable above 80°C, . The encapsulated pediocin showed stability since it retained 50% of its initial activity. The encapsulated pediocin showed 89% of encapsulation efficiency Conclusion: The encapsulated pediocin not only improved pediocin stability but also enhanced the controlled release of the antimicrobial substances, enough for inhibiting the foodborne pathogen L. monocytogenes.


1970 ◽  
Vol 24 (03/04) ◽  
pp. 325-333 ◽  
Author(s):  
G. H Tishkoff ◽  
L. C Williams ◽  
D. M Brown

SummaryAs a corollary to our previous studies with bovine prothrombin, we have initiated a study of human prothrombin complex. This product has been isolated in crystalline form as a barium glycoprotein interaction product. Product yields were reduced compared to bovine product due to the increased solubility of the barium glycoprotein interaction product. On occasion the crystalline complex exhibited good yields. The specific activity of the crystalline complex was 1851 Iowa u/mg. Further purification of human prothrombin complex was made by removal of barium and by chromatography on Sephadex G-100 gels. The final product evidenced multiple procoagulant activities (II, VII, IX and X). The monomeric molecular weight determined by sedimentation equilibrium in a solvent of 6 M guanidine-HCl and 0.5% mercaptoethanol was 70,191 ± 3,057 and was homogeneous with respect to molecular weight. This product was characterized in regard to physical constants and chemical composition. In general, the molecular properties of human prothrombin complex are very similar to the comparable bovine product. In some preparations a reversible proteolytic enzyme inhibitor (p-aminophenylarsonic acid) was employed in the ultrafiltration step of the purification scheme to inhibit protein degradation.


1992 ◽  
Vol 12 (1) ◽  
pp. 15-21
Author(s):  
S. Kojima ◽  
K. Nara ◽  
Y. Inada ◽  
S. Hirose ◽  
Y. Saito

Platelet aggregation activity due to platelet-activating factor (PAF) was detected at high molecular weight (HMW) and low molecular weight fractions after gel-filtration chromatography of cell lysate of endothelial cells. [3H]PAF added to the cell lysate was similarly distributed after chromatography. The radioactivity associated with HMW fraction was not reduced by digesting the lysate with trypsin, suggesting that PAF was not making complexes with proteins but was included in lipid vesicles in cell lysate. Further evidence showed that an unknown specific factor(s) was needed to form these PAF-containing lipid vesicles. Radioactivity was not found in HMW fraction when [3H]PAF was mixed with cell lysate of vascular smooth muscle cells. When monomeric PAF was added to endothelial cell lysate, the specific activity of aggregation decreased to the level exerted by endogenous PAF-containing lipid vesicles due to incorporation into lipid vesicles. PAF in the form of lipid vesicles was more stable in plasma than monomeric form.


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