Antimicrobial activity of secondary and tertiary poly(diallylammonium) salts (PDAAs) had not been reported before. Due to difficulties with preparation of polymers from the monomers of the diallylamine (DAA) series in the nonquaternary form, up to recently it was not possible to obtain PDAAs with a sufficiently high molecular mass. Here, we describe the investigations of antimicrobial activity of novel water-soluble cationic polyelectrolytes of the PDAA series, namely secondary poly(diallylammonium trifluoroacetate) (PDAATFA) and tertiary poly(diallylmethylammonium trifluoroacetate) (PDAMATFA), in synthesis of which we have recently succeeded, against gram-positive and gram-negative bacteria, and fungi. We have studied the effect of molecular weight (polymeric chain length) and ionic strength of solution on the biocidal efficiency of those polymers; in addition, the concentration dependences of PDAATFA reduced viscosity in salt-free and KCl aqueous solutions have been investigated. The antimicrobial properties of polybase polydiallylamine (BPDAA), which was obtained in an aqueous solution of PDAATFA in presence of alkali, have been also studied as well as biocidal activity of commercial open-chain polybase branched PEI. Those PDAATFA, BPDAA and PEI polymers served as the systems to study the structure-activity relationships. Transmission electronic microscopy study was carried out to characterize the mode of antimicrobial action of PDAATFA using E. coli . It was shown that the synthesized PDAATFA and PDAMATFA exhibit, unlike the quaternary polymers of this series, a rather high biocidal efficiency that is comparable with the activity of known effective cationic polymer biocides or exceeds it. Novel polyelectrolytes exhibit quite strong biocidal properties at different conditions including aqueous solutions of moderate ionic strength (serum, 0.01 M/0.1 M) and aqueous-alkaline solutions (pH 10.5) until the macrochain retains some positive charge, but complete neutralization of the polyelectrolyte in a 1 M salt solution results in the loss of its biocidal activity. The obtained results evidence that the structure of links, which combine the hydrophobic pyrrolidinium rings with the hydrophilic secondary/tertiary ammonium groups, is responsible for the high biocidal activity of the PDAAs. Polymeric nature of the synthesized compounds is one of the most significant factors of their bactericidal efficiency, unlike their high fungicidal activity, which is evidently related to the secondary/tertiary pyrrolidinium cycle.
Antibacterial effect of chitosan on the morphofunctional organization of clinical strains of Klebsiella pneumoniae and Staphylococcus aureus was studied by transmission electron microscopy. Chitosan promoted aggregation of bacterial cells and disorganization of bacterial cell wall and cytoplasmic membrane, which leads to the release of bacterial contents into the environment. These structural changes result in bacterial death.
A virus was isolated from Siberian sturgeon Acipenser baeri and bester (beluga Huso huso × sterlet A. ruthenus hybrid) fingerlings in SSO-2, SSF-2 and WSSK-1 cell lines during an acute epizootic on a large fish farm producing fertilised sturgeon eggs and fry. Transmission electron microscopic examination of samples from both inoculated cell cultures and skin of affected fish revealed viral particles with a herpesvirus-like morphology. The etiological role of the Siberian sturgeon herpesvirus (SbSHV) was confirmed by fulfilment of Rivers' postulates. Experimental immersion of healthy Siberian sturgeon fingerlings in a suspension of SbSHV resulted in 100% mortality with signs of focal epidermal hyperplasia, skin necrosis and multiple skin haemorrhages. While infecting different organs and tissues, the virus showed clear integumentary tropism. Carp fry and rainbow trout fingerlings were neither susceptible to the virus nor did they transmit it to healthy Siberian sturgeon. KEY WORDS: Siberian sturgeon. Herpesvirus . Pathogenicity Resale or republication not permitted without written consent of the publisherDis Aquat Org 86: 193-203, 2009 In the spring of 2006, an acute disease outbreak occurred in a large warm water sturgeon hatchery situated in Tver Province in the European part of Russia. The outbreak resulted in a mass mortality of fry and fingerlings, with Siberian sturgeon Acipenser baeri being the most susceptible fish among several sturgeon species cultured there. Up to 100% mortality was registered in some fish lots.The disease developed at a water temperature range of 14 to 19°C. Affected fish were lethargic, consumed no food, had a lighter colour than normal and remained at the rearing tank bottom. Multiple haemorrhages on the ventral part of the rostrum, around the mouth and on the abdominal and lateral body surfaces were the most prominent clinical signs. In moribund fish, the liver was extremely pale, almost white. Saprolegnia sp. and myxobacteria were also found in the skin and gill tissues of many of the diseased fish. However, treatments against these secondary invaders did not result in substantial improvement of fish condition. After parasites and bacteria were excluded as possible causes of the disease, affected tissues from diseased fish were sampled for virological examination. MATERIALS AND METHODSVirus isolation. For virological examinations, samples of affected mouth and gill tissues were collected from 17 fingerling Lena sturgeons (a race of Siberian sturgeon) aged 1.5 to 4 mo old, and from 2 fingerling 3 mo old besters (great sturgeon Huso huso × sterlet Acipenser ruthenus hybrids) each with a body weight between 3 and 25 g. The collected samples were pooled from 2 to 7 fish and transported to the laboratory in chilled (2 to 4°C) condition in Eagle's minimal essential medium (MEM) supplemented with 10% foetal calf serum (FCS; Life Technologies), penicillin (300 I.U. ml -1 ) and streptomycin (300 µg ml -1 ). The time interval between sampling the fish tissues and their pr...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.