Intracellular Polysaccharide Research Articles

Effect of Iris pseudacorus L. on polysaccharide composition and microcystins content of Microcystis aeruginosa

The present study aimed to explore the feedback mechanism of M. aeruginosa under the stress of I. pseudacorus L.. by determining the polysaccharide composition and microcystins (MCs) synthesis and release of M. aeruginosa through co-cultivation of I. pseudacorus L. and M. aeruginosa. The results of our investigation and observation have shown that, under the stress of 20 or 40 g/L of I. pseudacorus L., the contents of intracellular and extracellular MC-LR, and the intracellular polysaccharide (IPS), the bound extracellular polysaccharide (bEPS) of M. aeruginosa increased at first and then began to decrease gradually afterwards. And the maximum contents were (71.03±10.20) fg/cell, (0.66±0.07) fg/cell, (1.84±0.10) pg/cell, (1.11±0.11) pg/cell and (70.33±8.62) fg/cell, (0.64±0.10) fg/cell, (1.74± 0.17) pg/cell, (0.90± 0.12) pg/cell. I. pseudacorus L. had an adsorption-enrichment effect on MCs. The content of MC-LR in the roots were (8.37±1.58) ng/g and (4.33±1.31) ng/g when I. pseudacorus L. was 20 or 40 g/L, respectively.

Comparative study on the monosaccharide compositions, antioxidant and hypoglycemic activities in vitro of intracellular and extracellular polysaccharides of liquid fermented Coprinus comatus

Polysaccharides were one of the important active ingredients of medical fungi, on account of its unique role caused the widespread concern of researchers at home and abroad. Currently, the structure and antioxidant activity of Coprinus comatus (C. comatus) fruit bodies polysaccharides have been reported. However, there is no article on the simultaneous study of intracellular and extracellular polysaccharides of liquid fermented C. comatus (IPs, EPs) so far. Hence, this paper innovatively investigated the monosaccharide compositions, antioxidative activities and inhibition of α-amylase activity in vitro of IPs and EPs. In this study, we adopted the PMP pre-column derivatization combined with HPLC method to determine the monosaccharide compositions of the IPs and EPs. Besides, the total antioxidant capacity, DPPH radical scavenging capacity, ·OH radical scavenging ability and inhibition effect on α-amylase in vitro of crude polysaccharides (ICPs, ECPs) and deproteinized polysaccharides (IDPs, EDPs) were severally compared. Only three kinds of monosaccharides were detected in IPs. Among the monosaccharides tested, the EPs contained five kinds, of which galactose and xylose accounted for a large proportion. ICPs showed better antioxidant activity and inhibition of α-amylase activity. This article innovatively studied the IPs and EPs, which could lay the foundation for the deep development of C. comatus.

Comparative transcriptome analysis reveals the genetic basis underlying the biosynthesis of polysaccharides in Hericium erinaceus

BackgroundHericium erinaceus, also known as lion’s mane mushroom, is a widely distributed edible and medicinal fungus in Asian countries. H. erinaceus harbors diverse bioactive metabolites with anticancer, immunomodulating, anti-inflammatory, antimicrobial, antihypertensive, antidiabetic and neuroprotective properties. Although the chemical synthesis processes of these bioactive metabolites are known, the biosynthetic processes remain unknown.ResultsIn this study, we obtained the transcriptomes of six H. erinaceus strains using next-generation RNA sequencing and investigated the characteristics of the transcriptomes and biosynthesis of bioactive compounds, especially polysaccharides. The transcriptomes ranged in size from 46.58 to 58.14 Mb, with the number of unigenes ranging from 20,902 to 37,259 across the six H. erinaceus strains. Approximately 60% of the unigenes were successfully annotated by comparing sequences against different databases, including the nonredundant (NR), Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), clusters of orthologous groups for eukaryotic complete genomes (KOG) and Swiss-Prot databases. Most of the transcripts were putatively involved in signal transduction, carbohydrate metabolism, translation, transport and catabolism, and amino acid metabolism. Genes involved in polysaccharide biosynthesis were identified, and these genes encoded phosphoglucomutase (PGM), glucose phosphate isomerase (PGI), UDP-glucose pyrophosphorylase (UGP), glycoside hydrolase family proteins, glycosyltransferase family proteins and other proteins. Moreover, the putative pathway for the intracellular polysaccharide biosynthesis of H. erinaceus was analyzed. Additionally, the open reading frames (ORFs) and simple sequence repeats (SSRs) were predicted from the transcriptome data of the six strains.ConclusionsOverall, the present study may facilitate the discovery of polysaccharide biosynthesis processes in H. erinaceus and provide useful information for exploring the secondary metabolites in other members of the Basidiomycetes genus.

Enhanced lipid productivity of an oleaginous microalgal mutant strain Scenedesmus sp. Z-4 and the underlying differences responsible for its superior lipid accumulation over wild strain Scenedesmus sp. MC-1

In this work, the lipid productivity of an oleaginous microalgal mutant strain Scenedesmus sp. Z-4 was improved to a maximum of 204.2 mg L−1 d−1 by single factor optimization, when 10 g L−1 glucose, 0.8 g L−1 NaNO3, 0.04 g L−1 K2HPO4 and initial pH of 7.0 were used in batch culture. Furthermore, multi-scale comparisons between mutant strain Z-4 and wild strain MC-1 were made, including cell surface elements and functional groups, biomass production, lipid accumulation and intracellular component percentages. The total EPS (extracellular polymeric substances) content of mutant strain Z-4 was 42.1% higher than that of wild strain MC-1, mainly due to the increase of extracellular protein and polysaccharide. Remarkable decrease of intracellular polysaccharide was found in the cells of mutant strain Z-4, implying the reallocation of carbon fluxes. These findings may be beneficial to understand the superior lipid production of mutant strain Scenedesmus sp. Z-4.

Optimization of Ganoderma lucidum Polysaccharides Fermentation Process for Large-Scale Production.

The objective of this study was to increase the intracellular polysaccharide yield of Ganoderma lucidum. The accordingly optimized fermentation medium by central composite design method contains glucose 40gL-1, yeast powder 12gL-1, potassium dihydrogen phosphate 3gL-1, initial pH5.5, and inoculum size 10mL100mL-1. Under this condition, the predicted value of intracellular polysaccharide yield was 2.03gL-1. Shake flask experiments confirmed that the average intracellular polysaccharide yield was 1.98gL-1 similar to the predicted value. The yields of intracellular polysaccharides in the 5-L and 50-L fermentors were 2.59gL-1 and 2.65gL-1, respectively. The molecular weight distribution of intracellular and extracellular polysaccharides obtained was determined by HPSEC-MALLS-RI. The results showed that the weight-average molecular weight of component 1 in the intracellular crude polysaccharide was 4.695 × 106Da and the mass fraction was 58%. The weight-average molecular weight of component 2 in the extracellular polysaccharide was 5.554 × 104Da. The mass fraction was 94.9%. The liquid submerged fermentation process of G. lucidum mycelium obtained from this study has effectively increased the yield of intracellular polysaccharides. Its intracellular and extracellular polysaccharides have good immunological activity. Conceivably, the optimized process can be applied for the large-scale production.

Dark and photofermentation H2 production from hydrolyzed biomass of the potent extracellular polysaccharides producing cyanobacterium Nostoc commune and intracellular polysaccharide (glycogen) enriched Anabaena variabilis NIES-2095

The biological H2 production industry would be independent from other industries if it has its own supply of organic materials especially in non-agricultural countries. In this study, acid hydrolyzed biomass of the potent extracellular polysaccharides (EPSs) producing cyanobacterium Nostoc commune and glycogen (as intracellular polysaccharide) enriched Anabaena variabilis NIES-2095 were used as a cheap organic carbon feedstock for biological H2 production by two stages dark fermentation by Escherichia coli strain MWW and Clostridium acetobutylicum DSM-792 or Clostridium beijerinckii DSM-1820 and photofermentation by Rhodobacter capsulatus JCM-21090 under anaerobic conditions. Acid hydrolysis of air dried cyanobacterial biomass was conducted at optimum conditions of 4 M HCl at 120 °C in an autoclave for 30 min and subsequently neutralized and used as an organic carbon source for first stage dark fermentation followed by a second stage photofermentation. The facultative anaerobe Escherichia coli strain MWW was used for maintaining anaerobiosis. Escherichia coli strain MWW was isolated and identified by morphological and biochemical characterizations as well as molecular biological phylogenetic analysis of its 16S rDNA sequence. Nostoc commune was identified by morphological and microscopic characterizations and by 16S rDNA sequence phylogenetic analysis. The two stages dark fermentation by Escherichia coli and Clostridium acetobutylicum or Clostridium beijerinckii and photofermentation by Rhodobacter capsulatus produced in total 5.9 and 5.6 mol H2/mole reducing sugars of acid hydrolyzed Nostoc commune EPSs/biomass, respectively and 5.43 and 5 mol H2/mole reducing sugars of acid hydrolyzed biomass of glycogen enriched Anabaena variabilis, respectively. These results indicate a high potency of using cyanobacterial polysaccharides/biomass (extracellular polysaccharides and intracellular glycogen) as an organic carbon source for H2 production which would be of importance for non-agricultural countries.

Acidogenic Potential of Oral Bifidobacterium and Its High Fluoride Tolerance.

Bifidobacterium is frequently detected in early childhood caries and white spot lesions, indicating that it is a novel caries-associated bacterium. Bifidobacterium is known to possess a unique metabolic pathway, the “bifid shunt,” which might give it cariogenic potential by increasing its acid production. Thus, we evaluated the acid-producing activity of Bifidobacterium and its sensitivity to fluoride, a caries preventive reagent. Bifidobacterium longum, Bifidobacterium dentium, and Streptococcus mutans were used. Acid-producing activity was measured using a pH-stat in the absence and presence of fluoride under anaerobic conditions. Furthermore, metabolomic analysis was performed to elucidate the mechanism underlying the inhibitory effects of fluoride. The acid production of Bifidobacterium at pH 5.5 was as high as that seen at pH 7.0, indicating that Bifidobacterium has high cariogenic potential, although it produced less acid than S. mutans. In addition, Bifidobacterium produced acid in the absence of extracellular carbohydrates, suggesting that it can store intracellular polysaccharides. Bifidobacterium produced more acid from lactose than from glucose. Bifidobacterium mainly produced acetate, whereas S. mutans mainly produced lactate. The 50% inhibitory concentration (IC50) of fluoride for acid production was 6.0–14.2 times higher in Bifidobacterium than in S. mutans. Fluoride inhibited enolase in the glycolysis, resulting in the intracellular accumulation of 3-phosphoenolpyruvate, glucose 6-phosphate, and erythrose 4-phosphate. However, the bifid shunt provides a bypass pathway that can be used to produce acetate, suggesting that Bifidobacterium is able to metabolize carbohydrates in the presence of fluoride. It is suggested that its exclusive acetate production contributes to the pathogenesis of dental caries.

Antisense yycG Regulation of Antibiotic Sensitivity of Methicillin-Resistant Staphylococcus aureus in Chronic Osteomyelitis.

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is an urgent medical problem in osteomyelitis. The YycFG two-component regulatory system (TCS) allows bacteria to adapt rapidly to physical, chemical, and biological stresses. The recombinant plasmid shuttle vector was used to overexpress an antisense RNA (asRNA) to inhibit target gene expression by sequence-specific double-stranded RNA complex degradation. In the current study, antisense yycG RNA (ASyycG)-overexpression MRSA clinical isolates were constructed. Methods: Bacterial growth was monitored, and biofilm biomass was determined by crystal violet microtiter assay. Quantitative reverse transcription polymerase chain reaction analysis was used to identify expression of yycF/G/H and icaA/D in MRSA and ASyycG strains. The expression of YycG protein was quantified by Western blot assays. The antibiotic resistance of ASyycG strains was compared with that of the MRSA strains. Results: The ASyycG strains showed a decrease in growth rate compared with the MRSA strains. Of note, overexpression of ASyycG led to a reduction in biofilm formation and adhesion force. ASyycG strains had decreased expressions of the yycF/G/H and icaA/D. Furthermore, Western blot data showed that expression of the YycG protein decreased by 40% in ASyycG strains compared with MRSA strains. In addition, the effect of yycG asRNA improved the susceptibility of ASyycG strains to cefoxitin. Conclusions: The ASyycG strains inhibited biofilm organization and increased antibiotic sensitivity, which may be attributed to altered intracellular polysaccharide construction.

Comparative Chemical and Bioactivity Studies of Intra- and Extracellular Metabolites of Endophytic Bacteria, Bacillus subtilis NCIB 3610

Endophytic bacteria are able to produce unique bioactive compounds for various biotechnological applications. The intracellular and extracellular extracts of the endophytic bacterium, Bacillus subtilis NCIB 3610 were investigated for chemical composition as well as evaluated for antiviral, antimicrobial, antifungal and cytotoxic activities. The GC/MS analysis of intracellular and extracellular hexane extracts revealed that 2,6-di-t-butyl-4-methyl phenol was found as main compound in intracellular hexane extract, while pentacosane and hexacosane as well as 14-methyl hexadecanoic methyl ester were found as major metabolites in extracellular hexane extract. The intracellular and extracellular polysaccharides were isolated from aqueous extract which characterized as heteropolysaccharides bounded with protein. The yield of intracellular polysaccharide fraction (FC1) (42.17% ± 1.21) was higher than that of the extracellular polysaccharides fractions (FM1, FM2 and FM3) (12.68%). The GLC analysis of fractions revealed the presence of 8, 8, 6 and 9 monosaccharides, respectively, the fractions FC1, FM2 and FM3 composed mainly of galactose, mannose and glucose with weight-average molecular weight (Mw) 295.5, 165.5 and 129.8 kDa, respectively. The amino acid analysis of protein bounded to intra- and extracellular polysaccharide fractions revealed the presence of 17 amino acids. Glutamic acid and alanine were found as predominant amino acids in FC1, while glycine, glutamic and aspartic acids were existed as dominant amino acids in exopolysaccharide fractions. The anti-bacterial activity displayed that intracellular polysaccharide (FC1) has a promising antibacterial activity against Staphylococcus aureus and Streptococcus pneumoniae which gave 51.6 and 37% relative inhibition activity of Doxycyclin Hydrchloride. Moreover, the most fractions of intracellular and extracellular showed broad spectrum antifungal activity. The evaluation of cytotoxic activity of intracellular and extracellular fractions on HCT116, HepG2 and MCF7 human cell lines showed that intracellular chloroform, ethyl acetate and methanol fractions have a potent cytotoxic activity. Overall, the bioactive fractions obtained from Bacillus subtilis NCIB 3610 can be useful for biotechnological and pharmaceutical application as they showed cytotoxic and antimicrobial activities.

Advance in Cordyceps militaris (Linn) Link polysaccharides: Isolation, structure, and bioactivities: A review.

Cordyceps militaris is a unique and precious medical fungus in Chinese Cordyceps, which has been widely used as the traditional medicines or as biocontrol agents against pests in China for centuries. Polysaccharides are one of bioactive constituents in Cordyceps militaris with a variety of biological activities, including immunomodulation, antioxidant, anti-tumor, and anti-aging activities, among others. However, natural Cordyceps militaris are very rare and expensive, most of literatures indicated that the polysaccharides were mostly extracted from artificially cultivated fungal fruiting bodies (intracellular polysaccharides) or mycelia fermentation broths (extracellular polysaccharides). Moreover, separation and purification of polysaccharides was a very complicated and cumbersome process. Nevertheless, a large number of polysaccharides were purified and its characterization was elucidated by structure and biological activities. However, the relationship between structure and activity of polysaccharides has not been well established. Therefore, this review detailed the recent advance in several aspects (i.e., extraction, isolation, structure, and bioactivities) of the polysaccharides from fruiting body of Cordyceps militaris. This information could provide theoretical basis for the research on related polysaccharides, and also have important reference value in the field of functional foods and medicine in the future.

Study of mycelial polysaccharide from Paraisaria dubia of Ophiocordyceps gracilis asexual

In order to provide a foundation for the development and application of Ophiocordyceps gracilis and increase the new resources of cordyceps,an asexual Paraisaria dubia was isolated from an O. gracilis fruit body. After 10 days of liquid fermentation,white globular mycelium and clear transparent fermentation were produced. The mycelium was extracted by hot water and precipitated with ethanol to obtain intracellular crude polysaccharide. The protein was deproteinized to obtain deproteinized polysaccharide. The intracellular pure polysaccharide was purified by Sepharose 4 B column chromatography and were analyzed by UV,IR,1 H-NMR,and13 CNMR data,as well as GC and HPLC. The results showed that the intracellular polysaccharide of P. dubia was composed of glucose,galactose and mannose with a molar ratio of 25. 54 ∶2 ∶1. It was a β-configuration glycosylic bond,containing pyranoside. The initial connection of polysaccharide was β(1→2)(1→4)(1→6) connection. This experiment provides a theoretical basis for the development and application of P. dubia.

Effect of Intracellular and Extracellular Mushroom Polysaccharides on Growth Inhibition of Human Carcinoma Cell Lines

Introduction: Mushroom polysaccharides play an important role in nutraceutical and functional food because they act as biological active modifiers. The aim of the present work involved the production, purification and partial characterization of intracellular (IPS) and extracellular polysaccharides (EPS) from several basidiomycete strains. Such polysaccharides were used to investigate their effect on growth of human carcinoma cell lines. Methods: Mushroom polysaccharides were produced from several basidiomycete strains by submerged and solid state fermentations, assayed for superoxide radical scavenging activity, purified by gel filtration chromatography, analysed by FTIR and their effect on human carcinoma cell line was investigated by MTT method. Results: Mushroom polysaccharides have revealed scavenging activity in the range of 22 - 81 % for Po (s) and Pe (2), respectively. FTIR analysis of polysaccharides showed absorption bands characteristics of these biological macromolecules. IPS inhibited cell growth of HeLa in the range of 16.8 - 27.01 % for Po (s) and Ga (1), respectively. EPS inhibited cell growth of HeLa, A459, A431 and OE21 in the ranges of 3.08 - 92.2 %, 13.8 - 97.4 %, 14.7 - 93. 8% and 25 - 94% for Il (1) and Ga (1), Gc (1) and Ga (1), Il (1) and Ga (1), Le (1) and Ga (1), respectively. Purified preparations of polysaccharides confirmed the growth inhibition of these biomolecules. Conclusion: The present results strongly suggest growth inhibition of human carcinoma cell lines by mushroom polysaccharides and it will require a future research to understand its molecular mechanism of action.

Polysaccharides from the Edible Mushroom Agaricus bitorquis (Quél.) Sacc. Chaidam Show Anti-hypoxia Activities in Pulmonary Artery Smooth Muscle Cells.

Three kinds of new water-soluble polysaccharides (FA, FB and FC) were isolated from wild mushroom Agaricus bitorquis (Quél.) Sacc. Chaidam by the classical method “water extraction and alcohol precipitation” and purified by column chromatography. The Mw of FA, FB and FC ranged from 5690 Da to 38,340 Da. The three polysaccharide fractions in the fruiting body were mainly composed of 4 kinds of monosaccharides, including glucose, galactose, mannose, and arabinose, among which glucose and galactose were the major monosaccharides. The FTIR and NMR spectroscopy indicated that the skeleton of three fractions composed of a (1→4)-α-D-glycosidic backbone containing α-D-mannopyranose. In vitro anti-hypoxia activity data showed that three polysaccharide fractions possessed a significant effect on inhibiting PASM cells apoptosis under hypoxia. Among them, FC at the concentration of 200 µg/mL revealed a significant anti-hypoxia effect. These results revealed that the intracellular polysaccharides possessed potent anti-hypoxic activity, which might be related to inhibiting LDH and NADPH oxidase expression and promoting the formation of 5-hydroxytryptamine, dopamine, endothelins, acetylcholine. More importantly, FC showed good performance inducing KV1.5 expression and prohibiting KIR6.2 formation at protein level.

Effects of Atmospheric and Room Temperature Plasma (ARTP) Mutagenesis on Physicochemical Characteristics and Immune Activity In Vitro of Hericium erinaceus Polysaccharides

The polysaccharide is the main active substance contained in Hericium erinaceus and is commonly used in the treatment of neurasthenia, tumors, and digestive diseases. Six intracellular polysaccharide components were obtained from H. erinaceus fruiting bodies cultivated by ARTP (atmospheric and room temperature plasma) mutagenic strain (321) and the original strain (0605), respectively. This study was designed to investigate the physicochemical characteristics of these polysaccharide components and their potential immunomodulatory activities on RAW264.7 macrophages. The results showed that the yield of fruiting body cultivated by mutated strain increased by 22% and the polysaccharide content improved by 16% compared with the original one owing to ARTP mutagenesis. The molecular weight distribution and the monosaccharide compositions of polysaccharide components from H. erinaceus induced by ARTP mutagenesis were significantly different from that of the original one. The NO, IL-6, IL-10, IL-1β, and TNF-α production activities of macrophages were enhanced by stimulation of 20% ethanol precipitated polysaccharides from H. erinaceus induced by ARTP mutagenesis. These results indicated that ARTP is an efficient and practical method for high polysaccharide content breeding of the H. erinaceus strain and this provided a reference for obtaining high quality resources and healthy product development from H. erinaceus.

Biosynthesis of mycobacterial methylmannose polysaccharides requires a unique 1-O-methyltransferase specific for 3-O-methylated mannosides

Mycobacteria are a wide group of organisms that includes strict pathogens, such as Mycobacterium tuberculosis, as well as environmental species known as nontuberculous mycobacteria (NTM), some of which-namely Mycobacterium avium-are important opportunistic pathogens. In addition to a distinctive cell envelope mediating critical interactions with the host immune system and largely responsible for their formidable resistance to antimicrobials, mycobacteria synthesize rare intracellular polymethylated polysaccharides implicated in the modulation of fatty acid metabolism, thus critical players in cell envelope assembly. These are the 6-O-methylglucose lipopolysaccharides (MGLP) ubiquitously detected across the Mycobacterium genus, and the 3-O-methylmannose polysaccharides (MMP) identified only in NTM. The polymethylated nature of these polysaccharides renders the intervening methyltransferases essential for their optimal function. Although the knowledge of MGLP biogenesis is greater than that of MMP biosynthesis, the methyltransferases of both pathways remain uncharacterized. Here, we report the identification and characterization of a unique S-adenosyl-l-methionine-dependent sugar 1-O-methyltransferase (MeT1) from Mycobacterium hassiacum that specifically blocks the 1-OH position of 3,3'-di-O-methyl-4α-mannobiose, a probable early precursor of MMP, which we chemically synthesized. The high-resolution 3D structure of MeT1 in complex with its exhausted cofactor, S-adenosyl-l-homocysteine, together with mutagenesis studies and molecular docking simulations, unveiled the enzyme's reaction mechanism. The functional and structural properties of this unique sugar methyltransferase further our knowledge of MMP biosynthesis and provide important tools to dissect the role of MMP in NTM physiology and resilience.

Optimisation of biomass, exopolysaccharide and intracellular polysaccharide production from the mycelium of an identified Ganoderma lucidum strain QRS 5120 using response surface methodology.

Wild-cultivated medicinal mushroom Ganoderma lucidum was morphologically identified and sequenced using phylogenetic software. In submerged-liquid fermentation (SLF), biomass, exopolysaccharide (EPS) and intracellular polysaccharide (IPS) production of the identified G. lucidum was optimised based on initial pH, starting glucose concentration and agitation rate parameters using response surface methodology (RSM). Molecularly, the G. lucidum strain QRS 5120 generated 637 base pairs, which was commensurate with related Ganoderma species. In RSM, by applying central composite design (CCD), a polynomial model was fitted to the experimental data and was found to be significant in all parameters investigated. The strongest effect (p < 0.0001) was observed for initial pH for biomass, EPS and IPS production, while agitation showed a significant value (p < 0.005) for biomass. By applying the optimized conditions, the model was validated and generated 5.12 g/L of biomass (initial pH 4.01, 32.09 g/L of glucose and 102 rpm), 2.49 g/L EPS (initial pH 4, 24.25 g/L of glucose and 110 rpm) and 1.52 g/L of IPS (and initial pH 4, 40.43 g/L of glucose, 103 rpm) in 500 mL shake flask fermentation. The optimized parameters can be upscaled for efficient biomass, EPS and IPS production using G. lucidum.

The effect of fermentation conditions on the structure and anti-tumor activity of polysaccharides from Cordyceps gunnii.

This study investigates the effect of fermentation conditions on the structure and anti-tumor activity of intracellular polysaccharides (IPS) of Cordyceps gunnii (C. gunnii) in submerged fermentation. The environmental and nutritional conditions are determined in a shaker flask by a single factor test. The inhibition of IPS on S180 cells was as an optimization index. The results show that the optimal fermentation conditions of C. gunnii are an initial pH value of 6, a temperature of 25 °C, a rotation speed of 150 rpm, 4% glucose, and 1.0% peptone. Under these conditions, the macro molecular weight (Mw) polysaccharide content and anti-tumor activity of IPS are significantly higher than that in the basal culture medium. GC, HPGPC, periodate oxidation-Smith degradation, NMR, and FT-IR determine the structural characteristics of CPS-JC and CPS-YH (pure IPS cultured in basal culture medium and optimal culture medium, respectively). The results indicate that CPS-JC is mainly composed of α-d-glucans, whereas CPS-YH primarily contain α-d-glucans with a trace amount of β-d-glucans.

Retraction Note: Optimized extraction, composition, antioxidant and antimicrobial activities of exo and intracellular polysaccharides from submerged culture of Cordyceps cicadae

The editor has retracted this article [1] due to overlap with a previously published article [2]. Both articles also appear to use the same image representing different fungal mycelial growths. S.K. Sharma and N.S. Atri do not agree to this retraction. N. Gautam has not responded to correspondence from the editor about this retraction.

Effect of sucrose on biofilm formed in situ on titanium material.

Because sucrose may change the composition of biofilms formed on dental surfaces, the aim of this study was to evaluate in situ the effect of this dietary sugar on biofilm formation on titanium surface. In this blind, crossover, in situ study, 10 volunteers wore, in 3 phases of 7days each, a palatal appliance containing titanium specimens. In each phase, the specimens were treated extraorally with 20% sucrose solution at a frequency of 4 or 8times per day. As control, no treatment was rendered (0×). At the end of each phase, the biofilms were collected for biochemical analysis of biofilm wet weight (biomass), protein concentration, soluble (S-EPS), and insoluble (I-EPS) extracellular polysaccharides and intracellular polysaccharides (IPS), and for microbiologic analysis by checkerboard DNA-DNA hybridization (for levels and proportions of 40 bacterial species). Biochemical data were analyzed by linear regression and microbiological findings by Friedman and Dunn tests (α= .05). A positive significant linear relationship was found among sucrose exposure (0×, 4×, and 8×) and biomass, S-EPS, I-EPS and IPS (p< 0.05). The biofilms treated with sucrose (4× and/or 8×) presented higher mean total levels of the 40 bacterial species evaluated, higher proportions of red complex species and lower proportions of the host-compatible green complex species, in comparison with the control group (p< 0.05). The findings of the present study suggest that daily sucrose exposure has a harmful effect on the composition of biofilms formed on titanium surfaces.

Effects of crude extracellular protein and crude intracellular polysaccharides ofVibrio alginolyticuson the growth, energy metabolism regulation and WSSV resistance ofLitopenaeus vannamei

Effects of crude extracellular protein and crude intracellular polysaccharides of<i>Vibrio alginolyticus</i>on the growth, energy metabolism regulation and WSSV resistance of<i>Litopenaeus vannamei</i>