Carrageenan:chitosan (CG:CH) polyelectrolyte complexes (PEC) were obtained and the effect of the initial components ratio on formation was studied by dynamic light scattering, atomic force microscopy ...(AFM) and electrokinetic measurements. Positively charged PEC particles (average ζ-potential 40.2 mV) were formed, provided that the polycation was present in excess in the complex and was stabilized by chitosan amino groups. According to the AFM data, chitosan was located on the surface of the carrageenan fibers. In PEC where carrageenan prevailed, the number of unbound sulfate groups decreased when the chitosan content increased, this resulted in a decrease in the PEC negative surface charge (from −92.4 to −55.6 mV). In this case, AFM showed that chitosan was incorporated into the network structure of carrageenan and breaks it at a CG:CH ratio of 1:0.5 w/w. Complexes with a high content of kappa-CG inhibited biofilm formation by Gram negative and Gram positive microorganisms.
•Positively and negative charged particles of carrageenan:chitosan complexes were obtained.•Chitosan was located on the surface of the carrageenan fibers in positive charged complexes.•Chitosan incorporated into the network structure of carrageenan in negative charged complexes.•Complexes with a high content of carrageenan inhibited biofilm formation by microorganisms.
The taxonomic position of a novel marine, yellow-pigmented bacterium, designated strain KMM 6211(T), was examined by using a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene ...sequences revealed that strain KMM 6211(T) is a member of the family Flavobacteriaceae, phylum Bacteroidetes. The closest relative of strain KMM 6211(T) was Winogradskyella eximia KMM 3944(T), the sequence similarity being 97.1 %. The DNA G+C content of KMM 6211(T) was 33.6 mol%. The strain was motile by gliding and grew with 1-6 % NaCl and at 4-37 degrees C. Aesculin, casein and gelatin were hydrolysed, but agar, starch, DNA and chitin were not degraded. On the basis of phylogenetic data and phenotypic differences between the isolate and recognized Winogradskyella species, strain KMM 6211(T) represents a novel species of the genus Winogradskyella, for which the name Winogradskyella echinorum sp. nov. is proposed. The type strain is KMM 6211(T) (=KCTC 22026(T)=LMG 24757(T)).
The taxonomic position of four heterotrophic, aerobic, Gram-negative, non-motile and moderately halophilic marine bacteria, isolated from the green alga Acrosiphonia sonderi (Kütz) Kornm, was ...established. 16S rDNA sequence analysis indicated that the strains studied are members of the family Flavobacteriaceae, in which they form a distinct lineage. On the basis of phenotypic, chemotaxonomic, genotypic and phylogenetic data, the novel bacteria were classified as Mesonia algae gen. nov., sp. nov. The type strain is KMM 3909(T) (=KCTC 12089(T)=CCUG 47092(T)).
The effects of some hydrolytic enzymes from marine organisms on the formation and destruction of bacterial biofilms have been studied. As the results show, the presence of α-D-galactosidase from the ...marine bacterium
Pseudoalteromonas
sp. KMM 701 stimulates the growth of biofilms formed by various species of marine bacteria, whereas the formation of biofilms by
Bacillus subtilis
and
Yersinia pseudotuberculosis
is inhibited by this enzyme. Treatment with α-galactosidase causes destruction of 5 to 35% of a mature biofilm of various bacterial species. Phosphodiesterase and alkaline phosphatase from the marine bacterium
Cobetia amphilecti
KMM 296 have an inhibitory effect on the biofilm formation by marine strains of
Bacillus licheniformis
,
B. aegricola
, and
B. berkelogi
, and also degrade already formed biofilms of these bacilli and
Yersinia
. The crab hepatopancreas DNase inhibits the biofilm formation by
Y. pseudotuberculosis
and
B. subtilis
by partially degrading a mature biofilm.
Three strains of the marine, gliding, pigmented, facultatively anaerobic, heterotrophic, Gram-negative bacteria were isolated from the green algae Acrosiphonia sonderi (Kütz) Kornm and Ulva ...fenestrata Ruprecht inhabiting the Sea of Japan. 16S rDNA sequence analysis indicated that the strains were members of the family Flavobacteriaceae, in which they occupied separate lineages. The predominant cellular fatty acids were i15 : 0, a15 : 0, i15 : 1, 15 : 0, 15 : 1omega6c, i15 : 0 3-OH and i17 : 0 3-OH. The DNA base compositions were 31-33 mol% G+C. Based on the phenotypic, genotypic, chemotaxonomic and phylogenetic analyses, the novel bacteria should be placed in a novel taxon as Algibacter lectus gen. nov., sp. nov. with type strain KMM 3902G (=KCTC 12103T=DSM 15365T).
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