Исследование электрофизических свойств композиционных волокон на основе хитозана и полипиррола для тканевой инженерии

Composite fibers based on chitosan, coated with a conducting polymer, polypyrrole (PPyr), have been obtained. Their morphology was studied by scanning electron microscopy. The electrical conductivity of the fibers in a dry state and in a liquid culture medium simulating tissue fluid has been estimated. The values of resistivity, ro, and conductivity, sigma , of the investigated fibers are determined depending on the number of PPyr layers, the degree of drawing (orientation) of the fibers in dry and in liquid media. It was found that with an increase in the amount of drawing from 0 to 100%, ro of fibers decreases both in a dry state and in a liquid culture medium. In this case, the maximum drop ro of fibers upon immersion in a liquid culture medium was observed for undrawn fibers with two layers of PPyr. It was shown that after an initial drop in ro of oriented chitosan fibers with 1 and 2 layers of PPyr ro changes weakly in a liquid culture medium for 2 hours. The investigated oriented polymer fibers of chitosan coated with 1 and 2 layers of PPyr are promising for use in the field of tissue engineering and regenerative medicine.

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Sorption of Zinc by exopolysaccharides produced by liquid media of phytopatogenic fungi

ROMANIAN BIOTECHNOLOGICAL LETTERS ◽

10.25083/rbl/26.1/2312.2317 ◽

2021 ◽

Vol 26 (1) ◽

pp. 2312-2317

Author(s):

JUAN DIEGO VALENZUELA-COBOS ◽

ANA GRIJALVA-ENDARA

Keyword(s):

Yeast Extract ◽

Liquid Culture ◽

Culture Medium ◽

Colletotrichum Gloeosporioides ◽

Culture Media ◽

Phytopathogenic Fungi ◽

Mycelial Biomass ◽

Rhizopus Stolonifer ◽

Liquid Media ◽

Liquid Culture Medium

Phytopathogenic fungi such as: Colletotrichum gloeosporioides and Rhizopus stolonifer were cultivated in three different liquid culture media: LCC (glucose 40 g L-1 , yeast extract 3 g L-1 ), LC2 (glucose 40 g L-1 , yeast extract 3 g L-1 and tryptone peptone 2 g L-1 ) and LC3 (glucose 40 g L-1 , yeast extract 3 g L-1 and tryptone peptone 10 g L-1 ) under pH of 5.5 for the production of mycelial biomass and exopolysaccharides (EPS). The liquid culture medium (LC3) used in cultivation of Colletotrichum gloeosporioides showed the highest production of biomass (15.40 g L-1 ) and exopolysaccharides (3.40 g L-1 ). Exopolysaccharides (EPS) obtained from the liquid culture medium (LC3) of Colletotrichum gloeosporioides presented the highest absorption content of Zinc (56 mg g-1 ). The results presented that the exopolysaccharides (EPS) produced by Colletotrichum gloeosporioides showed the greatest biosorbent capacity of Zinc (Zn) using the culture medium with the highest amount of tryptone peptone.

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Observations of Germinating Lychnis Alba Pollen

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010006578x ◽

1971 ◽

Vol 29 ◽

pp. 348-349

Author(s):

Richard E. Crang ◽

Michael A. Millay

Keyword(s):

Electron Microscopy ◽

Pollen Tube ◽

Liquid Culture ◽

Culture Medium ◽

Tube Wall ◽

Pollen Grains ◽

Pharbitis Nil ◽

Liquid Culture Medium ◽

Transmission Electron ◽

Pollen Tube Wall

The exine surface of Lychnis alba pollen grains is ornamented with spines and pits (Fig. 1) that are variable both in size and number. No relationship appears to exist between the relative nature of these surface features as observed by means of scanning electron microscopy (SEM) and germination potentials of the pollen. The protrusion of cytoplasm at the apertures is a common phenomenon as the grains become hydrated when placed in liquid culture medium. As swelling of the apertures occurs, the aperturate opercula, or pore plates, may be lifted to the terminal surface but frequently are displaced to one side where they become embedded in the pollen tube wall (Fig.2). Although all apertures may protrude, only a single pollen tube will normally form from each grain. The composition of the opercula appear similar to the exine in transmission electron microscopy (TEM) preparations, but is less dense than the exine when observed in SEM preparations, as indicated by surface folds suggestive of a soft composition. There is no structural evidence that enzyme degradations of the exine at germination sites is required for emergence of the pollen tube, although such may be the case when pollen germinates on the style as indicated in SEM observations of Pharbitis nil pollen.

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Actinomycetes in discolored wood of living silver maple

Canadian Journal of Botany ◽

10.1139/b81-001 ◽

1981 ◽

Vol 59 (1) ◽

pp. 1-7 ◽

Cited By ~ 13

Author(s):

Robert A. Blanchette ◽

John B. Sutherland ◽

Don L. Crawford

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Carbon Source ◽

Cell Walls ◽

Hydroxybenzoic Acid ◽

Liquid Media ◽

Streptomyces Strain ◽

Culture Techniques ◽

Silver Maple ◽

Scanning Electron

The greenish-brown margin of discolored wood in three living silver maple trees, Acer saccharinum L., was examined by scanning electron microscopy and microbiological culture techniques. Micrographs of xylem vessels revealed filamentous structures; some of them appeared to be actinomycetous hyphae. Actinomycetes identified as Streptomyces parvullus Waksman & Gregory, S. sparsogenes Owen, Dietz & Camiener, and a third Streptomyces strain were isolated repeatedly from discolored wood of each tree. These isolates grew in liquid media in the presence of 0.1% (w/v) concentrations of several phenols. Although other phenols included in the test were not substantially degraded, p-hydroxybenzoic acid was utilized as a carbon source by S. parvullus. All three actinomycetes inhibited growth of selected wood-inhabiting fungi when paired on malt agar. When inoculated on sterilized sapwood and discolored wood from silver maple, the actinomycetes colonized vessel walls and occlusions, but were not observed to decay cell walls.

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Isolation of previously uncultured rumen bacteria by dilution to extinction using a new liquid culture medium

Journal of Microbiological Methods ◽

10.1016/j.mimet.2010.10.011 ◽

2011 ◽

Vol 84 (1) ◽

pp. 52-60 ◽

Cited By ~ 51

Author(s):

Nikki Kenters ◽

Gemma Henderson ◽

Jeyamalar Jeyanathan ◽

Sandra Kittelmann ◽

Peter H. Janssen

Keyword(s):

Liquid Culture ◽

Culture Medium ◽

Rumen Bacteria ◽

Liquid Culture Medium

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Investigations on Liquid Culture Medium as a Means of Anther Culture in Nicotiana

Zeitschrift für Pflanzenphysiologie ◽

10.1016/s0044-328x(76)80058-x ◽

1976 ◽

Vol 79 (3) ◽

pp. 189-198 ◽

Cited By ~ 50

Author(s):

W. Wernicke ◽

H.W. Kohlenbach

Keyword(s):

Anther Culture ◽

Liquid Culture ◽

Culture Medium ◽

Liquid Culture Medium

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FORMATION OF TRYPSIN FROM TRYPSINOGEN BY AN ENZYME PRODUCED BY A MOLD OF THE GENUS PENICILLIUM

The Journal of General Physiology ◽

10.1085/jgp.21.5.601 ◽

1938 ◽

Vol 21 (5) ◽

pp. 601-620 ◽

Cited By ~ 43

Author(s):

M. Kunitz

Keyword(s):

Temperature Coefficient ◽

Acid Medium ◽

Experimental Error ◽

Protein Concentration ◽

Liquid Culture ◽

Culture Medium ◽

Specific Activity ◽

Crystalline Form ◽

Liquid Culture Medium ◽

Autocatalytic Activation

1. A powerful kinase which changes trypsinogen to trypsin was found to be present in the synthetic liquid culture medium of a mold of the genus Penicillium. 2. The concentration of kinase in the medium is increased gradually during the growth of the mold organism and continues to increase for some time even after the mold has ceased growing. 3. Mold kinase transforms trypsinogen to trypsin only in an acid medium. It differs thus from enterokinase and trypsin which activate trypsinogen best in a slightly alkaline medium. 4. The action of the mold kinase in the process of transformation of trypsinogen is that of a typical enzyme. The process follows the course of a catalytic unimolecular reaction, the rate of formation of a definite amount of trypsin being proportional to the concentration of kinase added. The ultimate amount of trypsin formed, however, is independent of the concentration of kinase used. 5. The formation of trypsin from trypsinogen by mold kinase is not accompanied by any measurable loss of protein. 6. The temperature coefficient of formation of trypsin from trypsinogen by mold kinase varies from Q5–15 = 1.70 to Q25–30 = 1.25 with a corresponding variation in the value of µ from 8100 to 4250. 7. Trypsin formed from trypsinogen by means of mold kinase is identical in crystalline form with the crystalline trypsin obtained by spontaneous autocatalytic activation of trypsinogen at pH 8.0. The two products have within the experimental error the same solubility and specific activity. A solution saturated with the crystals of either one of the trypsin preparations does not show any increase in protein concentration or activity when crystals of the other trypsin preparation are added. 8. The Penicillium mold kinase has a slight activating effect on chymo-trypsinogen the rate being only 1–2 per cent of that of trypsinogen. The activation, as in the case of trypsinogen, takes place only in an acid medium. 9. Mold kinase is rapidly destroyed when brought to pH 6.5 or higher, and also when heated to 70°C. In the temperature range of 50–60°C. the inactivation of kinase follows a unimolecular course with a temperature coefficient of Q10 = 12.1 and µ = 53,500. The molecular weight of mold kinase, as determined by diffusion, is 40,000.

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Detection Method for Histamine-Producing, Dairy-Related Bacteria using Diamine Oxidase and Leucocrystal Violet

Journal of Food Protection ◽

10.4315/0362-028x-52.2.105 ◽

1989 ◽

Vol 52 (2) ◽

pp. 105-108 ◽

Cited By ~ 35

Author(s):

SUSAN S. SUMNER ◽

STEVE L. TAYLOR

Keyword(s):

Hydrogen Peroxide ◽

Liquid Culture ◽

Diamine Oxidase ◽

Culture Medium ◽

Detection Method ◽

Enzyme System ◽

Color Formation ◽

Liquid Culture Medium ◽

Leucocrystal Violet ◽

Purple Color

A detection method for histamine-producing, dairy-related bacteria was developed that involves a two-step sequential enzyme system. First, isolated bacteria are incubated in MRS broth or trypticase soy broth fortified with histidine. The histamine formed during this incubation period is reacted with diamine oxidase, which catalyzes the oxidation of histamine to form imidazole acetaldehyde, ammonia, and hydrogen peroxide. The hydrogen peroxide is then detected by the formation of crystal violet from the leuco base in the presence of horseradish peroxidase. Liquid culture medium containing bacteria that produce greater than 1200 nmole histamine per ml will develop a positive purple color. Cultures containing bacteria that produce little or no histamine will not develop a purple color. Other amines often found in cheese, such as tyramine, cadaverine, or putrescine, will not interfere with the color formation.

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A PROCEDURE FOR RAPID RECOVERY OF AFLATOXINS FROM CHEESE AND OTHER FOODS1

Journal of Milk and Food Technology ◽

10.4315/0022-2747-34.3.119 ◽

1971 ◽

Vol 34 (3) ◽

pp. 119-123 ◽

Cited By ~ 17

Author(s):

C. N. Shih ◽

E. H. Marth

Keyword(s):

Liquid Culture ◽

Culture Medium ◽

Peanut Butter ◽

Corn Meal ◽

Water Fraction ◽

Food Residue ◽

Liquid Culture Medium ◽

Chloroform Layer ◽

Sequential Addition ◽

Chloroform Methanol

A rapid and efficient method has been developed to recover aflatoxin from cheese and other foods. The procedure involves: (a) blending the sample with a mixture of chloroform, methanol, and water (solvents are used in such proportions that a miscible (monophasic) system is formed, (b) adding more chloroform and water so the mixture becomes biphasic, (c) filtering to remove the food residue, (d) separating the lower chloroform layer which contains virtually all of the aflatoxin, and (e) purification, if necessary, of the material in step (d) after it has been concentrated. Purification is achieved by sequential addition of methanol, water, and hexane; recovery of tho methanol-water fraction; and extraction of aflatoxins from it with chloroform. Purification can be eliminated if the substrate contains little or no lipid or pigment which, if present, interfere with thin-layer chromaographic analysis. Extraction can be done in approximately 35 min and purification in approximately 20 min. When aflatoxins were added to various substrates, the method recovered 92–98% B1 and 96–100% G1 from rice; 95–96% B1 and 90–95% G1 from peanut butter; 93–94% B1 and 92–98% G1 from Cheddar cheese; 100% B1 and G1 from corn meal; 91–100% B1, 91–100% B2, 90–96% G1, and 92–100% G2 from brick cheese; and 97–100% B1, 95–100% B2, 92–100% G1, and 98–100% G2 from a liquid culture medium.

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