Specificities of actions of fucoidanases from the marine microorganism Pseudoalteromonas citrea KMM 3296 and the marine mollusk Littorina kurila were studied. The enzymes possess similar ...specificities and catalyze the cleavage of accessible alpha -(1 arrow right 3)-fucoside bonds in fucoidans with highly sulfated alpha -(1 arrow right 4; 1 arrow right 3)-L-fucooligosaccharides. A high degree of sulfation of the fucose residues in fucoidans makes alpha -(1 arrow right 3)-L-fucoside bonds inaccessible for the action of the studied enzymes. The maximum degree of cleavage of fucoidan was achieved by the fucoidanase from the marine bacterium Pseudoalteromonas citrea KMM 3296.
Glycosidase activities of 177 strains of the phylum
Bacteroidetes
, belonging to 18 genera and isolated from the algae
Chondrus
sp.,
Polysiphonia
sp.,
Neosiphonia japonica, Saccharina crassifolia, ...Saccharina japonica, Chorda filum, Acrosiphonia sonderi
, and
Ulva fenestrata
collected in the littoral zones of the Sea of Okhotsk and the Sea of Japan, Pacific Ocean, were studied. According to the data obtained, glycosidases catalyzing hydrolysis of the β-glycoside bond were present in over 70% epiphytes of marine algae. It should be noted that α-galactosidases and the extremely rare enzymes, α-
N
-acetylgalactosaminidases, were more frequent in the
Bacteroidetes
than in the proteobacteria analyzed previously. It was found that the overwhelming majority of the bacteria of the dominant genera
Zobellia
and
Maribacter
contained the complete set of the tested glycosidases involved in degradation of algal polysaccharides. Apparently, the presence of the wide range of glycosidases in bacterial strains of these genera makes it possible for them to occupy diverse ecological niches under extreme conditions of the tidal zone. However, such important enzymes of the microbial lytic complex as α-galactosidases, β-galactosidases, or β-xylosidases, were not detected in the numerically important genus
Winogradskyella
. The noted difference in the metabolic profiles of the strains of these genera suggests the assumption that
Winogradskyella
strains play an unique role in the microbial communities, unrelated to the hydrolysis of such polysaccharides as agar and carrageenan. Significant differences in production of glycosidases among the different taxonomic groups were revealed, which is of importance for directed search of promising enzymes for biotechnology.
A search for fucoidan-degrading enzymes and other O-glycosylhydrolases has been performed among 51 strains of marine bacteria of the family Flavobacteriaceae isolated from red, green, and brown ...algae, as well as from the sea urchin Strongylocentrotus intermedius and the holothurian Apostichopus japonicus. Over 40% of the studied strains synthesized fucoidanases. The marine bacteria Mesonia algae KMM 3909 super(T) (an isolate from green alga Acrosiphonia sonderi), as well as Maribacter sp. KMM 6211 and Gramella sp. KMM 6054 (associants of the sea urchin S. intermedius), were the best producers of fucoidanases. Xylose effectively induced the biosynthesis of fucoidanases in these strains. None of the 15 strains of marine bacteria belonging to the genus Arenibacter produced polysaccharide hydrolases.
The purpose of this work was to design a nonenzymatic test system based on carbon nanoparticles for noninstrumental detection of antibodies to the species specific proteins of Y. pseudotuberculosis ...to improve the quality of diagnostics of the pseudotuberculosis infection.
The marine bacterium Pseudoalteromonas citrea KMM 3297 is an associate of the holothurian Apostichopus japonicus. When grown in a medium containing glucose, the strain produces two intracellular ...alginolytic enzymes, AlI and AlII. Fucoidan from the brown alga Fucus evanescens induces synthesis of one more alginolytic enzyme, AlIII. These enzymes were separated using anion-exchange chromatography. The alginate lyase AlI completely retains its activity at 35 degrees C, AlII and AlIII being stable at 45 degrees C. The alginate lyases exhibit maximal activities in the range of pH 7-8. The molecular weights of AlI, AlII, and AlIII determined by gel filtration are 25, 79, and 61 kD, respectively. All the investigated enzymes are endo-type alginate lyases. They catalyze degradation of polyguluronate (poly-G) and polymannuronate (poly-M) yielding oligosaccharides of the polymerization degree of 5 > or = n > or = 3 with the unsaturated bond between the C4 and C5 atoms of the non-reducing terminus. A mixture of these three enzymes exhibits synergism while acting on the polymeric substrate. The Km values of the alginate lyase AlI for poly-G and poly-M are 24 and 34 micro g/ml, respectively. Alginate lyase AlIII exhibits less affinity to poly-M (Km = 130.0 microg/ml) than to poly-G (Km = 40.0 microg/ml). NaCl (0.2 M), MgCl2 and MgSO4 (0.01 M) activate all three enzymes more than twofold. The presence of several alginolytic enzymes of different specificity provides efficient destruction of alginic acids of brown algae by the strain P. citrea KMM 3297.
Occurrence of α-N-acetylgalactosaminidases among 177 strains of marine bacteria of the phylum
Bacteroidetes
, epiphytes of marine algae growing on the littoral of the Seas of Okhotsk and Japan, was ...studied. About 36% of the isolates studied contained α-N-acetylgalactosaminidase. All of the bacteria of the genus
Arenibacter
(species
A. latericius, A. certesii
, and
A. palladensis
), irrespective of the source of isolation, synthesized this enzyme. The greatest number of α-N-acetylgalactosaminidase producers was found among the isolates from the algae
Neosiphonia japonica, Acrosiphonia sonderi
, and
Ulva fenestrata
sampled in the Cove of Trinity, Posyet Bay, the Sea of Japan. These were mainly bacteria of the genera
Zobellia
(50%) and
Maribacter
(58%). Among the epibionts studied, the bacteria
Arenibacter latericius
KMM 3523, an epiphyte of the brown alga
Chorda filum
from the Sea of Okhotsk, and
Cellulophaga
sp. KMM 6488, an epiphyte of the green alga
Acrosiphonia sonderi
from the Sea of Japan, were marked as the most promising sources of the enzyme. The results of this study showed that aerobic nonpathogenic marine
Bacteroidetes
, algal associants not requiring special cultivation conditions, are the promising, economical, and ecologically pure sources of unique and biotechnologically significant α-N-acetylgalactosaminidases.
A total of twenty aerobic endospore-forming bacilli, isolated from marine invertebrates and sea water of different areas of the Pacific Ocean, were taxonomically characterized. Most of the bacilli ...(11 strains) of marine origin belonged to the species Bacillus subtilis, according to their phenotypic characteristics, antibiotic susceptibility profiles, and fatty acids patterns. A group of four alkaliphilic strains formed a separate cluster that was tentatively classified as B. horti. One isolate, KMM 1717, associated with a sponge from the Coral Sea was identified as B. pumilus. Two strains, Bacillus KMM 1916 and KMM 1918, showed antibiotic sensitivity profiles similar to B. licheniformis, but they had a distinct fatty acid composition and peculiar phenotypic traits. The taxonomic affiliation of KMM 1810 and KMM 1763 remained unclear since their fatty acid composition and antibiotic sensitivity patterns were not resembled with none of these obtained for Bacillus strains.
Although bacteria of the genus
Shewanella belong to one of the readily cultivable groups of
“Gammaproteobacteria”, little is known about the occurrence and abundance of these microorganisms in the ...marine ecosystem. Studies revealed that of 654 isolates obtained from marine invertebrates (ophiuroid
Amphiopholis kochii, sipuncula
Phascolosoma japonicum, and holothurian
Apostichopus japonicus,
Cucumaria japonica), seawater and sediments of the North-West Pacific Ocean (i.e. the Sea of Japan and Iturup Is, Kurile Islands), 10.7% belonged to the genus
Shewanella. The proportion of viable
Shewanella species varied from 4% to 20% depending on the source of isolation. From the isolation study, representative strains of different phenotypes (from seventy presumptive
Shewanella strains) were selected for detailed characterization using phenotypic, chemotaxonomic, and phylogenetic testing. 16S rDNA sequence-based phylogenetic analysis confirmed the results of tentative identification and placed the majority of these strains within only a few species of the genus
Shewanella with 98–99% of 16S rDNA sequences identity mainly with
S. japonica and
S. colwelliana, suggesting that the strains studied might belong to these species. Numerically dominant strains of
S. japonica were metabolically active and produced proteinases (gelatinases, caseinases), lipases, amylases, agarases, and alginases.
Shewanella strains studied demonstrated weak antimicrobial and antifungal activities that might be an indication of their passive role in the colonization on living and non-living surfaces.
An α-galactosidase capable of converting B red blood cells into the universal blood type cells at the neutral pH was produced by a novel obligate marine bacterium strain KMM 701 (VKM B-2135 D). The ...organism is heterotrophic, aerobic, and halophilic and requires Na^sup +^ ions and temperature up to 34°C for its growth. The strain has a unique combination of polysaccharide-degrading enzymes. Its single intracellular α-galactosidase exceeded other glycoside hydrolases in the level of expression up to 20-fold. The α-galactosidase was purified to determine the N-terminal amino acid sequences and new activities. It was found to inhibit Corynebacterium diphtheria adhesion to host buccal epithelium cell surfaces with high effectiveness. The nucleotide sequence of the homodimeric α-galactosidase indicates that its subunit is composed of 710 amino acid residues with a calculated Mr of 80,055. This α-galactosidase shares structural property with 36 family glycoside hydrolases. The properties of the enzyme are likely to be highly beneficial for medicinal purposes. PUBLICATION ABSTRACT
Foreign governments have used social media to influence politics in a range of countries by promoting propaganda, advocating controversial viewpoints, and spreading disinformation. We analyze 53 ...distinct foreign influence efforts (FIEs) targeting 24 different countries from 2013 through 2018. FIEs are defined as (i) coordinated campaigns by one state to impact one or more specific aspects of politics in another state (ii) through media channels, including social media, (iii) by producing content designed to appear indigenous to the target state. The objective of such campaigns can be quite broad and to date have included influencing political decisions by shaping election outcomes at various levels, shifting the political agenda on topics ranging from health to security, and encouraging political polarization. We draw on more than 460 media reports to identify FIEs, track their progress, and classify their features.
