scholarly journals Bacterial surfactants as agents with antibiofilm activity

2021 ◽  
Vol 16 (1) ◽  
pp. 94-104
Author(s):  
А.Е. Abaturov
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Low Molecular Weight ◽  
Antibiofilm Activity ◽  
Antibiotic Resistant ◽  
Biological Surface ◽  
The Matrix ◽  
Surface Active ◽  
Bacteria And Fungi ◽  
Surface Active Compounds

Biosuragents are a heterogeneous group of biological surface-active amphiphilic compounds. The producers of biosurfactants are various microorganisms: bacteria and fungi. The class of biosurfactants consists of two groups: low molecular weight and high molecular weight compounds. Representatives of low molecular weight compounds are lipopeptides, glycolipids, fatty acids, phospholipids that reduce surface and interfacial tension, and high molecular weight compounds are polymer and dispersed biosurfactants, which are emulsion stabilizers. The most studied biosurfactants with the potential of drugs are lipopeptides and glycolipids. A subgroup of lipopeptides are polymyxins, pseudo-factins, putisolvins, surfactin, fengycin and others; and glycoli­pids — rhamnolipids, trehalose, sophorose, cellobiose, mannosileritritol lipids, and others. Biosurfactants play a key role in the life of biofilms: they regulate the adhesion of bacteria and biofilm matrix, support the functioning of the matrix channels, providing the nutrient needs of bacteria. It has also been shown that biosurfactants are involved in the formation and dispersion of formed biofilms. These substances, directly reacting with the components of the matrix, induce degradation of the biofilm. Biosurfing agents, possessing antimicrobial, antifungal and antiviral, and antitumor properties, are a promising class of compounds that, possessing a combination of antibacterial and antibiofilm action, open up new perspectives in the treatment of recurrent chronic infectious di­seases. It is believed that surface-active compounds, both representatives of lipopeptides and glycolipids, can be the molecular basis for the development of drugs that will enhance the effectiveness of antibiotic therapy for problem infections, especially those caused by antibiotic-resistant strains.

The Effect of Dextran of Various Molecular Weight on the Coagulation in Dogs

1961 ◽  
Vol 06 (01) ◽  
pp. 015-024 ◽  
Author(s):  
Sven Erik Bergentz ◽  
Oddvar Eiken ◽  
Inga Marie Nilsson
Keyword(s):  
Molecular Weight ◽  
Body Weight ◽  
High Molecular Weight ◽  
Bleeding Time ◽  
Factor Vii ◽  
Low Molecular Weight ◽  
Factor V ◽  
Coagulation Mechanism ◽  
Coagulation Defects

Summary1. Infusions of low molecular weight dextran (Mw = 42 000) to dogs in doses of 1—1.5 g per kg body weight did not produce any significant changes in the coagulation mechanism.2. Infusions of high molecular weight dextran (Mw = 1 000 000) to dogs in doses of 1—1.5 g per kg body weight produced severe defects in the coagulation mechanism, namely prolongation of bleeding time and coagulation time, thrombocytopenia, pathological prothrombin consumption, decrease of fibrinogen, prothrombin and factor VII, factor V and AHG.3. Heparin treatment of the dogs was found to prevent the decrease of fibrinogen, prothrombin and factor VII, and factor V otherwise occurring after injection of high molecular weight dextran. Thrombocytopenia was not prevented.4. In in vitro experiments an interaction between fibrinogen and dextran of high and low molecular weight was found to take place in systems comprising pure fibrinogen. No such interaction occurred in the presence of plasma.5. It is concluded that the coagulation defects induced by infusions of high molecular weight dextran are due to intravascular coagulation.

scholarly journals Antiparasitic antibodies occur with similar frequency in patients with clinically established multiple sclerosis with or without oligoclonal bands in the cerebrospinal fluid

2013 ◽  
Vol 71 (8) ◽  
pp. 512-515 ◽  
Author(s):  
Fabiana Cruz Gomes da Fonseca-Papavero ◽  
Dagoberto Callegaro ◽  
Paulo Diniz da Gama ◽  
Jose Antonio Livramento ◽  
Adelaide Jose Vaz ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Molecular Weight ◽  
High Molecular Weight ◽  
Hygiene Hypothesis ◽  
Oligoclonal Bands ◽  
Parasitic Infections ◽  
Low Molecular Weight ◽  
Serum Samples ◽  
Similar Frequency ◽  
Electrophoresis Of Proteins

The "hygiene hypothesis" postulates an inverse relationship between the prevalence of parasitic infections and the frequency of multiple sclerosis (MS). Objective: It was to study whether antibodies against parasites could be demonstrated more frequently in blood serum from MS patients with oligoclonal bands (OCB) than from MS patients without OCB. Methods: We studied serum samples from 164 patients who had previously been analyzed to investigate OCB. Parasitic antibodies were studied through unidimensional electrophoresis of proteins on polyacrylamide gel against Taenia antigens, searching for antiparasitic specific low molecular weight antibodies and also for antiparasitic nonspecific high molecular weight antibodies. Results: Two of the 103 patients with no evidence of OCB had antibodies of low molecular weight and 59 of them had antibodies of high molecular weight. Of the 61 patients with evidence of OCB, one showed antibodies of low molecular weight and 16 showed antibodies of high molecular weight. Conclusion: Antiparasitic antibodies are detected with similar frequency in MS patients with OCB and in MS patients without OCB.

Simultaneous Isolation of Wheat High Molecular Weight and Low Molecular Weight Glutenin Subunits

1998 ◽  
Vol 28 (1) ◽  
pp. 25-32 ◽  
Author(s):  
I.M. Verbruggen ◽  
W.S. Veraverbeke ◽  
A. Vandamme ◽  
J.A. Delcour
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Low Molecular Weight ◽  
Glutenin Subunits

scholarly journals The interrelations between high- and low-molecular-weight forms of normal and mutant (Krabbe-disease) galactocerebrosidase

1980 ◽  
Vol 189 (1) ◽  
pp. 9-15 ◽  
Author(s):  
Yoav Ben-Yoseph ◽  
Melinda Hungerford ◽  
Henry L. Nadler
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Specific Activity ◽  
Polyacrylamide Gel Electrophoresis ◽  
Active Form ◽  
Sodium Dodecyl ◽  
Krabbe Disease ◽  
Low Molecular Weight ◽  
Molecular Weight Form

Galactocerebrosidase (β-d-galactosyl-N-acylsphingosine galactohydrolase; EC 3.2.1.46) activity of brain and liver preparations from normal individuals and patients with Krabbe disease (globoid-cell leukodystrophy) have been separated by gel filtration into four different molecular-weight forms. The apparent mol.wts. were 760000±34000 and 121000±10000 for the high- and low-molecular-weight forms (peaks I and IV respectively) and 499000±22000 (mean±s.d.) and 256000±12000 for the intermediate forms (peaks II and III respectively). On examination by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, the high- and low-molecular-weight forms revealed a single protein band with a similar mobility corresponding to a mol.wt. of about 125000. Antigenic identity was demonstrated between the various molecular-weight forms of the normal and the mutant galactocerebrosidases by using antisera against either the high- or the low-molecular-weight enzymes. The high-molecular-weight form of galactocerebrosidase was found to possess higher specific activity toward natural substrates when compared with the low-molecular-weight form. It is suggested that the high-molecular-weight enzyme is the active form in vivo and an aggregation process that proceeds from a monomer (mol.wt. approx. 125000) to a dimer (mol.wt. approx. 250000) and from the dimer to either a tetramer (mol.wt. approx. 500000) or a hexamer (mol.wt. approx. 750000) takes place in normal as well as in Krabbe-disease tissues.

scholarly journals Biodegradation of low molecular weight polyacrylamide under aerobic and anaerobic conditions: effect of the molecular weight

2020 ◽  
Vol 81 (2) ◽  
pp. 301-308 ◽  
Author(s):  
Wenzhe Song ◽  
Yu Zhang ◽  
Amir Hossein Hamidian ◽  
Min Yang
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Carbon Chain ◽  
Anaerobic Treatment ◽  
Low Molecular Weight ◽  
Amino Groups ◽  
Molecular Weights ◽  
Weight One ◽  
Hydrolysis Of ◽  
Aerobic And Anaerobic

Abstract The biodegradation of polyacrylamide (PAM) includes the hydrolysis of amino groups and cleavage of the carbon chain; however, the effect of molecular weight on the biodegradation needs further investigations. In this study, biodegradation of low molecular weight PAM (1.6 × 106 Da) was evaluated in two aerobic (25 °C and 40 °C) and two anaerobic (35 °C and 55 °C) reactors over 100 days. The removal of the low molecular weight PAM (52.0–52.6%) through the hydrolysis of amino groups by anaerobic treatment (35 °C and 55 °C) was much higher than that of the high molecular weight (2.2 × 107 Da, 11.2–17.0%) observed under the same conditions. The molecular weight was reduced from 1.6 × 106 to 6.45–7.42 × 105 Da for the low molecular weight PAM, while the high molecular weight PAM declined from 2.2 × 107 to 3.76–5.87 × 106 Da. The results showed that the amino hydrolysis of low molecular weight PAM is easier than that of the high molecular weight one, while the cleavage of its carbon chain is still difficult. The molecular weights of PAM in the effluents from the two aerobic reactors (25 °C and 40 °C) were further reduced to 4.31 × 105 and 5.68 × 105 Da by the biofilm treatment, respectively. The results would be useful for the management of wastewater containing PAM.

Calcium-Dependent Cross-Linking Processes in Platelets

1979 ◽  
Author(s):  
I. Cohen ◽  
T. Glaser
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Cross Linking ◽  
Low Molecular Weight ◽  
Tracer Concentration ◽  
Calcium Dependent ◽  
A 23187 ◽  
Polymer Formation ◽  
Total Disappearance ◽  
Low Molecular Weight Proteins

When platelet cytoplasmic Ca2+ is increased by the ionophore A 23187, there is the coincident appearance of a cross-linked polymer and the partial disappearance of five high molecular weight polypeptide bands (> 145,000). The glycoproteins show a partial disappearance of bands lb, IIb and IV and the total disappearance of hands la and Ilia. The disappearance of the protein bands, possibly contributing to the polymer formation, is prevented by histamine, aminoacetonltrile and cystamlne, which, as pseudodonor amines are known Inhibitors of factor XHIa-catalyzed cross-linking. 14C-histamine, at a tracer concentration, was incorporated into the polymer as well as into myosin, glycoproteins IIb and IIIa (α-actinln), actin and two unidentified low-molecular weight proteins. The polymer formed is also apparent in isolated membranes following the iono-phore-stimulated increase in intracellular Ca2+. These findings are unrelated to a proteolytic activity since the platelet Ca2+-dependent proteases are inhibited by leupep-tin. Ca2+-activation of a platelet cytosol transamidase would explain the data obtained. This platelet transamidase(s) may couple membrane proteins to cytoplasmic contra-tlle proteins. Thus, a new concept is proposed for the stabilization of platelet membranes and platelets as they form the hemostatic plug.

scholarly journals Experimental Research on the Optimization and Evaluation of the Polymer/Chromium-Ion Deep Profile Control System for the Fractured Low-Permeability Reservoirs

Processes ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1021
Author(s):  
Daiyin Yin ◽  
Shuang Song ◽  
Qi Xu ◽  
Kai Liu
Keyword(s):  
Molecular Weight ◽  
Control System ◽  
High Molecular Weight ◽  
Low Molecular Weight ◽  
Low Permeability ◽  
Chromium Ion ◽  
Oil Displacement ◽  
Profile Control ◽  
Deep Profile ◽  
Plugging Performance

The matrix/fracture conductivity of a fractured low-permeability reservoir is variable, and its heterogeneity is serious. When carrying out deep profile control measures, it is difficult to inject under the premise of ensuring the plugging effect. According to the characteristics of the fractured low-permeability reservoir in Chaoyanggou Oilfield, the polymer/chromium ion deep profile control system was optimized via a viscosity evaluation experiment, liquidity experiment and oil displacement experiment. The experimental results show that the high molecular weight main agent/low concentration system and low molecular weight main agent/high concentration system can meet the gel strength requirement. The evaluation results of the injection ability and plugging performance of the fractured low-permeability core show that a high molecular weight profile control system is difficult to inject, while a low molecular weight profile control system has a poor plugging performance and high cost after simulated shear. Therefore, the formulation of the profile control system was determined to be a polymer with a molecular weight of 16 million g·mol−1 as the main agent with a concentration of 1000–1500 mg·L−1. As assisting agents, the concentrations of thiourea, NaCl and NaHCO3 were 900 mg·L−1, 800 mg·L−1 and 700 mg·L−1, respectively. The plugging rate of the system was 87.6%, and the resistance coefficient was 19.2. Finally, a fractured low-permeability core model with parallel long cores was designed, and the optimal profile control system was used for the core oil-displacement experiment. Compared with the water-flooding experiment, the plugging rate can be increased by 6.9–8.0%.

8 Final Report on the Safety Assessment of Polyquaternium-11

1983 ◽  
Vol 2 (5) ◽  
pp. 161-178 ◽  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Skin Irritation ◽  
Low Molecular Weight ◽  
Final Report ◽  
Dermal Toxicity ◽  
Molecular Weight Polymer ◽  
Patch Tests ◽  
Skin Patch ◽  
Available Information

Polyquaternium-11 is a quaternized copolymer of vinylpyrrolidone and di-methylamine ethylmethacrylate, and is used at concentrations up to 50% in a variety of hair care preparations. The acute oral LD50 in test animals of high molecular weight Polyqua-ternium-11 is estimated to be greater than 12.8 g/kg; the LD50 for the low molecular weight polymer is calculated to be 6.2 g/kg. At concentrations of up to 50% in water, the raw ingredient produced no signs of skin or eye irritation. There was no evidence of dermal toxicity in subchronic tests nor in a maximization test for sensitization. In clinical studies, 1 of 19 subjects showed slight skin irritation after a 24-hour single insult skin patch with 9.5% Polyquaternium-11 in water. Repeated insult patch tests at concentrations up to 50% produced no instances of skin sensitization and only isolated instances of transient skin irritation. Clinical photoreactivity studies on both low and high molecular weight polymers showed no evidence of phototoxicity or photoallergenicity. From the available information, it is concluded that Polyquaternium-11 is safe as a cosmetic ingredient in the present practices of use.

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