scholarly journals Acetan and Acetan-Like Polysaccharides: Genetics, Biosynthesis, Structure, and Viscoelasticity

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 815
Author(s):  
Janja Trček ◽  
Iztok Dogsa ◽  
Tomaž Accetto ◽  
David Stopar
Keyword(s):  
Bacterial Species ◽  
Acetic Acid Bacteria ◽  
Original Description ◽  
Bioinformatic Analysis ◽  
Industrial Sector ◽  
Water Soluble ◽  
Extracellular Polysaccharides ◽  
Genetic Cluster ◽  
Water Release ◽  
Komagataeibacter Xylinus

Bacteria produce a variety of multifunctional polysaccharides, including structural, intracellular, and extracellular polysaccharides. They are attractive for the industrial sector due to their natural origin, sustainability, biodegradability, low toxicity, stability, unique viscoelastic properties, stable cost, and supply. When incorporated into different matrices, they may control emulsification, stabilization, crystallization, water release, and encapsulation. Acetan is an important extracellular water-soluble polysaccharide produced mainly by bacterial species of the genera Komagataeibacter and Acetobacter. Since its original description in Komagataeibacter xylinus, acetan-like polysaccharides have also been described in other species of acetic acid bacteria. Our knowledge on chemical composition of different acetan-like polysaccharides, their viscoelasticity, and the genetic basis for their production has expanded during the last years. Here, we review data on acetan biosynthesis, its molecular structure, genetic organization, and mechanical properties. In addition, we have performed an extended bioinformatic analysis on acetan-like polysaccharide genetic clusters in the genomes of Komagataeibacter and Acetobacter species. The analysis revealed for the first time a second acetan-like polysaccharide genetic cluster, that is widespread in both genera. All species of the Komagataeibacter possess at least one acetan genetic cluster, while it is present in only one third of the Acetobacter species surveyed.

scholarly journals In situ identification of Gram-negative bacteria in human lungs using a topical fluorescent peptide targeting lipid A

2018 ◽  
Vol 10 (464) ◽  
pp. eaal0033 ◽  
Author(s):  
Ahsan R. Akram ◽  
Sunay V. Chankeshwara ◽  
Emma Scholefield ◽  
Tashfeen Aslam ◽  
Neil McDonald ◽  
...  
Keyword(s):  
Lipid A ◽  
Respiratory Infections ◽  
Bacterial Species ◽  
Water Soluble ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Human Lungs ◽  
Fluorescent Peptide ◽  
Bacterial Lipid

Respiratory infections in mechanically ventilated patients caused by Gram-negative bacteria are a major cause of morbidity. Rapid and unequivocal determination of the presence, localization, and abundance of bacteria is critical for positive resolution of the infections and could be used for patient stratification and for monitoring treatment efficacy. Here, we developed an in situ approach to visualize Gram-negative bacterial species and cellular infiltrates in distal human lungs in real time. We used optical endomicroscopy to visualize a water-soluble optical imaging probe based on the antimicrobial peptide polymyxin conjugated to an environmentally sensitive fluorophore. The probe was chemically stable and nontoxic and, after in-human intrapulmonary microdosing, enabled the specific detection of Gram-negative bacteria in distal human airways and alveoli within minutes. The results suggest that pulmonary molecular imaging using a topically administered fluorescent probe targeting bacterial lipid A is safe and practical, enabling rapid in situ identification of Gram-negative bacteria in humans.

Effects of Fluoride, Lithium and Strontium on Extracellular Polysaccharide Production by Streptococcus mutans and Actinomyces viscosus

1981 ◽  
Vol 60 (C) ◽  
pp. 1601-1610 ◽  
Author(s):  
Patrick Treasure
Keyword(s):  
Trace Elements ◽  
Streptococcus Mutans ◽  
Extracellular Polysaccharide ◽  
Water Soluble ◽  
Extracellular Polysaccharides ◽  
Polysaccharide Production

Effects of trace elements on production of extracellular polysaccharides (EPS) by S. mutans and A. viscosus were examined in vitro. Fluoride enhanced EPS production. Lithium and strontium had little effect alone, but tended to reverse the effect of fluoride. The proportion of water-soluble EPS and the proportion of glucosyl-EPS were increased by fluoride.

scholarly journals Structural analysis of a new carotenoid-binding protein: the C-terminal domain homolog of the OCP

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Maria Agustina Dominguez-Martin ◽  
Michal Hammel ◽  
Sayan Gupta ◽  
Sigal Lechno-Yossef ◽  
Markus Sutter ◽  
...  
Keyword(s):  
Bioinformatic Analysis ◽  
Water Soluble ◽  
Structural Description ◽  
X Ray ◽  
Terminal Domain ◽  
New Family ◽  
X Ray Scattering ◽  
Water Soluble Protein ◽  
Orange Carotenoid Protein ◽  
Critical Residues

Abstract The Orange Carotenoid Protein (OCP) is a water-soluble protein that governs photoprotection in many cyanobacteria. The 35 kDa OCP is structurally and functionally modular, consisting of an N-terminal effector domain (NTD) and a C-terminal regulatory domain (CTD); a carotenoid spans the two domains. The CTD is a member of the ubiquitous Nuclear Transport Factor-2 (NTF2) superfamily (pfam02136). With the increasing availability of cyanobacterial genomes, bioinformatic analysis has revealed the existence of a new family of proteins, homologs to the CTD, the C-terminal domain-like carotenoid proteins (CCPs). Here we purify holo-CCP2 directly from cyanobacteria and establish that it natively binds canthaxanthin (CAN). We use small-angle X-ray scattering (SAXS) to characterize the structure of this carotenoprotein in two distinct oligomeric states. A single carotenoid molecule spans the two CCPs in the dimer. Our analysis with X-ray footprinting-mass spectrometry (XFMS) identifies critical residues for carotenoid binding that likely contribute to the extreme red shift (ca. 80 nm) of the absorption maximum of the carotenoid bound by the CCP2 dimer and a further 10 nm shift in the tetramer form. These data provide the first structural description of carotenoid binding by a protein consisting of only an NTF2 domain.

Enhancing of Acetic Acid Production in Vinegar Production by the Consortium of Aspergillus spp. and Yeasts

2017 ◽  
Vol 866 ◽  
pp. 61-64
Author(s):  
Duongruitai Nicomrat
Keyword(s):  
Acetic Acid ◽  
Acid Production ◽  
Raw Materials ◽  
Bacterial Species ◽  
Acetic Acid Bacteria ◽  
Sugar Production ◽  
Acetic Acid Production ◽  
Fermented Broth ◽  
Two Stages ◽  
Diverse Groups

Fresh fruit vinegar fermentation is well known for the activities of diverse groups of microorganisms at two stages of the fermentation process. Their species diversity depend on the raw materials fermented. In the study, at the first step of high sugar production, less culturable acetic acid bacterial species but more Aspergillus spp. and yeasts, non-Saccharomyces were detected. At the end, the vinegar production step, the fermented broth showed only dominant acetic acid bacteria. In the study, yeasts and fungi were isolated and inoculated to the juice. The results showed that these consortium could help increase high alcohol and later more acetic acid production when compared with the control fruit vinegar fermentation.

scholarly journals The composition of the cell wall of Fusicoccum amygdali

1971 ◽  
Vol 125 (2) ◽  
pp. 461-471 ◽  
Author(s):  
K. W. Buck ◽  
M. A. Obaidah
Keyword(s):  
Cell Wall ◽  
Sodium Hydroxide ◽  
Cell Walls ◽  
Digestive Enzymes ◽  
Helix Pomatia ◽  
Water Soluble ◽  
Extracellular Polysaccharides ◽  
Lytic Enzymes ◽  
Similar Nature ◽  
Dark Blue

1. The cell wall of Fusicoccum amygdali consisted of polysaccharides (85%), protein (4–6%), lipid (5%) and phosphorus (0.1%). 2. The main carbohydrate constituent was d-glucose; smaller amounts of d-glucosamine, d-galactose, d-mannose, l-rhamnose, xylose and arabinose were also identified, and 16 common amino acids were detected. 3. Chitin, which accounted for most of the cell-wall glucosamine, was isolated in an undegraded form by an enzymic method. Chitosan was not detected, but traces of glucosamine were found in alkali-soluble and water-soluble fractions. 4. Cell walls were stained dark blue by iodine and were attacked by α-amylase, with liberation of glucose, maltose and maltotriose, indicating the existence of chains of α-(1→4)-linked glucopyranose residues. 5. Glucose and gentiobiose were liberated from cell walls by the action of an exo-β-(1→3)-glucanase, giving evidence for both β-(1→3)- and β-(1→6)-glucopyranose linkages. 6. Incubation of cell walls with Helix pomatia digestive enzymes released glucose, N-acetyl-d-glucosamine and a non-diffusible fraction, containing most of the cell-wall galactose, mannose and rhamnose. Part of this fraction was released by incubating cell walls with Pronase; acid hydrolysis yielded galactose 6-phosphate and small amounts of mannose 6-phosphate and glucose 6-phosphate as well as other materials. Extracellular polysaccharides of a similar nature were isolated and may be formed by the action of lytic enzymes on the cell wall. 7. About 30% of the cell wall was resistant to the action of the H. pomatia digestive enzymes; the resistant fraction was shown to be a predominantly α-(1→3)-glucan. 8. Fractionation of the cell-wall complex with 1m-sodium hydroxide gave three principal glucan fractions: fraction BB had [α]D +236° (in 1m-sodium hydroxide) and showed two components on sedimentation analysis; fraction AA2 had [α]D −71° (in 1m-sodium hydroxide) and contained predominantly β-linkages; fraction AA1 had [α]D +40° (in 1m-sodium hydroxide) and may contain both α- and β-linkages.

BIOSYNTHESIS OF EXTRACELLULAR POLYSACCHARIDES BY THE BLUE-GREEN ALGA ANABAENA FLOS-AQUAE

1965 ◽  
Vol 11 (6) ◽  
pp. 877-885 ◽  
Author(s):  
B. G. Moore ◽  
R. G. Tischer
Keyword(s):  
Green Alga ◽  
Water Soluble ◽  
Molar Ratio ◽  
Extracellular Polysaccharides ◽  
Blue Green Alga ◽  
Total Carbohydrate ◽  
Carbon Reduction ◽  
Reduction Cycle ◽  
Phosphorylated Compounds ◽  
Carbon Reduction Cycle

Extracellular polysaccharides were isolated from the blue-green alga Anabaena flos-aquae strain A-37. The polysaccharides are composed of glucuronic acid, glucose, xylose, and ribose in a molar ratio of 1:88:39:3. The extracellular polysaccharides comprise about 40% of the total carbohydrate produced by this alga.Carbon utilization experiments revealed that only D-fructose could be substituted for carbon dioxide as a precursor of polysaccharides and cellular material.The extracellular polysaccharides are derived from water-soluble intracellular polysaccharides of the same composition.Fructose accumulates in stationary phase cells grown in CO2 and the presence of the enzymes fructose diphosphate phosphatase and fructose diphosphate aldolase was demonstrated. Tracer studies showed the presence of phosphorylated compounds common to the photosynthetic carbon reduction cycle and the glycolytic pathway.

scholarly journals Lactobacillus kefiranofaciens: From Isolation and Taxonomy to Probiotic Properties and Applications

2021 ◽  
Vol 9 (10) ◽  
pp. 2158
Author(s):  
Marina Georgalaki ◽  
Georgia Zoumpopoulou ◽  
Rania Anastasiou ◽  
Maria Kazou ◽  
Effie Tsakalidou
Keyword(s):  
Bacterial Species ◽  
Starter Culture ◽  
Blood Lipid ◽  
Growth Conditions ◽  
Water Soluble ◽  
Growth Media ◽  
Rrna Gene ◽  
Probiotic Properties ◽  
Kefir Grain ◽  
Health Promoting

One of the main lactic acid bacterial species found in the kefir grain ecosystem worldwide is Lactobacillus kefiranofaciens, exhibiting strong auto-aggregation capacity and, therefore, being involved in the mechanism of grain formation. Its occurrence and dominance in kefir grains of various types of milk and geographical origins have been verified by culture-dependent and independent approaches using multiple growth media and regions of the 16S rRNA gene, respectively, highlighting the importance of their combination for its taxonomic identification. L. kefiranofaciens comprises two subspecies, namely kefiranofaciens and kefirgranum, but only the first one is responsible for the production of kefiran, the water-soluble polysaccharide, which is a basic component of the kefir grain and famous for its technological as well as health-promoting properties. L. kefiranofaciens, although very demanding concerning its growth conditions, can be involved in mechanisms affecting intestinal health, immunomodulation, control of blood lipid levels, hypertension, antimicrobial action, and protection against diabetes and tumors. These valuable bio-functional properties place it among the most exquisite candidates for probiotic use as a starter culture in the production of health-beneficial dairy foods, such as the kefir beverage.

scholarly journals Effects of brief sodium fluoride treatment on the growth of early and mature cariogenic biofilms

2021 ◽  
Author(s):  
Ye Han
Keyword(s):  
Sodium Fluoride ◽  
Biofilm Formation ◽  
Water Soluble ◽  
Laser Scanning Microscopy ◽  
Extracellular Polysaccharides ◽  
Antibiofilm Activity ◽  
Fluoride Treatment ◽  
Formation Stage ◽  
Early Formation ◽  
Cariogenic Biofilm

Abstract Although fluoride has been widely used in the prevention of dental caries, the effect of fluoride on the activity of biofilm in different stages of cariogenic biofilm formation is less studied. This study aimed to investigate the antibiofilm activity of sodium fluoride during early and mature Streptococcus mutans (S. mutans) biofilms formation. S. mutans biofilms were formed on saliva-coated hydroxyapatite disks. In the early (0 ~ 46 h) and mature (46 ~ 94 h) biofilm stages, the biofilm was treated with different concentrations of fluoride (250, 500, 1000, 2000 ppm; 5 times in total, 1 min/treatment). Acidogenicity, dry weight, colony-forming units, water-soluble/insoluble extracellular polysaccharides (EPS), and intracellular polysaccharides were analyzed and confocal laser scanning microscopy images were obtained of the two stages of biofilms (early and mature biofilms). To determine the antibiofilm activity of sodium fluoride during the formation of early and mature biofilms, and to evaluate the relationship between different concentrations of sodium fluoride and antibiofilm activity. In the early cariogenic biofilm formation stage, all fluoride concentration test groups (250, 500, 1000, 2000 ppm) significantly inhibited the growth of S. mutans biofilm. The antibiofilm and anti-EPS formation activities of the brief fluoride treatment increased in a concentration-dependent pattern. At the mature biofilm stage, only the 2000 ppm fluoride treatment group significantly inhibited biofilm accumulation, activity, and intracellular/extracellular polysaccharide content compared with the control and other fluoride treatment groups. The antimicrobial activity of fluoride is related to the formation stage of cariogenic biofilm. The early formation stage of cariogenic biofilm is more susceptible to the inhibition of fluorine than the mature stage. The fluoride treatment in the early formation stage of cariogenic biofilm may be an effective means to control the development of cariogenic biofilm and prevent caries.

scholarly journals Effects of cigarette smoking on the growth of Streptococcus mutans biofilms: an in vitro study

2021 ◽  
Author(s):  
Ye Han
Keyword(s):  
Treatment Group ◽  
Cigarette Smoking ◽  
Streptococcus Mutans ◽  
Laser Scanning ◽  
Water Soluble ◽  
Laser Scanning Microscopy ◽  
Extracellular Polysaccharides ◽  
Confocal Laser ◽  
Control Group

Abstract This study aimed to investigate the differences in growth and virulence (EPSs and acidogenicity) of Streptococcus mutans biofilms (S. mutans) according to the different times of cigarette smoking (CS) treatment. S. mutans biofilms (74-hour-old) were formed on saliva-coated hydroxyapatite disks. The biofilms were treated with CS at different times per day (one time, three times, and six times/day). The control group did not receive CS treatment. Acidogenicity, dry weight, colony-forming units, water-soluble/insoluble extracellular polysaccharides, and intracellular polysaccharides were analyzed and confocal laser scanning microscopy images were obtained of the 74-h-old biofilms. The 74-h-old biofilms on sHA discs in the 6 times/day CS treatment group showed the lowest biofilm accumulation and extracellular polysaccharide amount compared with the control group and other CS treatment groups. In the CLSM study, the biofilms in the six times/day CS treatment group also showed the lowest bacterial count (live and dead cells) and EPS biovolume. CS has an obvious inhibition on the growth of S. mutans biofilms, the degree of inhibition is proportional to the number of CS treatments.

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