Mannose Moieties Research Articles

Preparation of glycopolypeptides bearing mannose moieties and biphenyl pendants and their upper‐critical‐solution‐temperature‐type thermoresponsive properties in alcohol/water solvent mixtures

AbstractA series of glycopolypeptides with constant main‐chain lengths and various compositions of mannose moieties and biphenyl pendants were synthesized by copper‐mediated 1,3‐dipolar cycloadditions. 1H NMR and Fourier transform IR (FTIR) analysis confirmed the molecular structures of the resulting polypeptides. FTIR analysis characterized the molar contents of the mannose pendants and α‐helical conformations in the solid state. Glycopolypeptides conjugated with tetra‐O‐acetyl‐d‐(+)‐mannopyranoside showed a reversible upper‐critical‐solution‐temperature‐type (UCST‐type) phase behavior both in MeOH/H2O and EtOH/H2O binary solvent mixtures depending on the weight percentage of alcohols (fw). Incorporation of a low content of biphenyl pendants (≤0.20) can broaden the range of fw at which polymers showed UCST‐type phase behaviors. The UCST‐type transition temperature (Tpt) was highly related to the incorporation of biphenyl pendants, polymer concentrations, and the nature and weight percentage of alcohols. It decreased as the polymer concentration decreased and increased on incorporation of biphenyl groups. © 2016 Society of Chemical Industry

Impact of oxidative and osmotic stresses on Candida albicans biofilm formation

Candida albicans possesses an ability to grow under different host-driven stress conditions by developing robust protective mechanisms. In this investigation the focus was on the impact of osmotic (2M NaCl) and oxidative (5 mM H2O2) stress conditions during C. albicans biofilm formation. Oxidative stress enhanced extracellular DNA secretion into the biofilm matrix, increased the chitin level, and reduced virulence factors, namely phospholipase and proteinase activity, while osmotic stress mainly increased extracellular proteinase and decreased phospholipase activity. Fourier transform infrared and nuclear magnetic resonance spectroscopy analysis of mannan isolated from the C. albicans biofilm cell wall revealed a decrease in mannan content and reduced β-linked mannose moieties under stress conditions. The results demonstrate that C. albicans adapts to oxidative and osmotic stress conditions by inducing biofilm formation with a rich exopolymeric matrix, modulating virulence factors as well as the cell wall composition for its survival in different host niches.

(Invited) Sugar/Nanocarbon Hybrids As Multivalent Inhibitors of Artificial Ebola Virus Infection

In the burgeoning area of nanoscience, scientists are currently focusing their attention on carbon nanomaterials for biomedical applications. The chemical modification of these nanomaterials is allowing to increase their biocompatibility and to provide new biological properties.At the molecular level, there are a wide variety of examples where multivalency drastically enhances the interactions between biomolecules in comparison with the monovalent binding. In particular, multivalency plays a key role in the protein-glycan recognition events which usually take place in the initial steps of pathogenic infection and also at some stages of the immune response. The search for high-affinity ligands for the study and understanding of the mechanisms involved in multivalent interactions has yielded a wide variety of artificial glycoconjugates which include, among others, glycopolymers, glycodendrimers, and glyconanoparticles. SWCNTs and SWCNHs constitute a less-explored type of unconventional and biocompatible scaffolds for the preparation of new glycoconjugates for a multivalent presentation of carbohydrates. Recently, we have shown that fullerene sugar balls, namely hexakis-adducts of [60]fullerene appended with 12, 24 or 36 mannose moieties, act as strong inhibitors for DC-SIGN in an Ebola infection assay model.1 Furthermore, a drastic increase in the inhibition process to the subnanomolar scale has been observed when the size and mannoses´ number are increased in the tridecafullerenes endowed with 120 mannose units decorating the periphery of the molecule.2 In this work, we report how SWCNTs and SWCNHs have been employed as virus mimicking nanocarbons platforms for the multivalent presentation of carbohydrates in an artificial Ebola virus infection model. These carbon nanoforms have been chemically modified by the covalent attachment of glycofullerenes using the CuAAC “click chemistry” approach. This modification dramatically increases the water solubility of these structurally different nanocarbons. Their efficiency to block DC-SIGN mediated viral infection by an artificial Ebola virus has been tested in a cellular experimental assay finding that, in contrast to SWCNTs, glycoconjugates based on 3D Dahlia Flower shaped SWCNHs are potent inhibitors of viral infection.

ALG1-CDG: Clinical and Molecular Characterization of 39 Unreported Patients.

Congenital disorders of glycosylation (CDG) arise from pathogenic mutations in over 100 genes leading to impaired protein or lipid glycosylation. ALG1 encodes a β1,4 mannosyltransferase that catalyzes the addition of the first of nine mannose moieties to form a dolichol-lipid linked oligosaccharide intermediate required for proper N-linked glycosylation. ALG1 mutations cause a rare autosomal recessive disorder termed ALG1-CDG. To date 13 mutations in 18 patients from 14 families have been described with varying degrees of clinical severity. We identified and characterized 39 previously unreported cases of ALG1-CDG from 32 families and add 26 new mutations. Pathogenicity of each mutation was confirmed based on its inability to rescue impaired growth or hypoglycosylation of a standard biomarker in an alg1-deficient yeast strain. Using this approach we could not establish a rank order comparison of biomarker glycosylation and patient phenotype, but we identified mutations with a lethal outcome in the first two years of life. The recently identified protein-linked xeno-tetrasaccharide biomarker, NeuAc-Gal-GlcNAc2 , was seen in all 27 patients tested. Our study triples the number of known patients and expands the molecular and clinical correlates of this disorder.

Cooperative Orthogonal Macromolecular Assemblies with Broad Spectrum Antiviral Activity, High Selectivity, and Resistance Mitigation

Treatment of viral infections continues to be elusive owing to the variance in virus structure (RNA, DNA, and enveloped and nonenveloped viruses) together with their ability to rapidly mutate and garner resistance. Here we report a general strategy to prevent viral infection using multifunctional macromolecules that were designed to have mannose moieties that compete with viruses for immune cells, and basic amine groups that block viral entry through electrostatic interactions and prevent viral replication by neutralizing the endosomal pH. We showed that cells treated with the antiviral polymers inhibited TIM receptors from trafficking virus, likely from electrostatic and hydrogen-bonding interactions, with EC50 values ranging from 2.6 to 6.8 mg/L, depending on the type of TIM receptors. Molecular docking computations revealed an unexpected, and general, specific hydrogen-bonding interactions with viral surface proteins, and virus and cell binding assay demonstrated a significant reduction in infection af...

Synthesis of Mannosylated Lipopeptides with Receptor Targeting Properties

Present on the surface of antigen presenting cells (APCs), the mannose receptor (MR) has long been recognized as a front-line receptor in pathogen recognition. During the past decade many attempts have been made to target this receptor for applications including vaccine and drug development. In the present study, a library of vaccine constructs comprising fluorescently labeled mannosylated lipid-dendrimers that contained the ovalbumin CD4(+) epitope, OVA(323-339), as the model peptide antigen were synthesized using fluorenylmethyloxycarbonyl (Fmoc) solid phase peptide synthesis (SPPS). The vaccine constructs were designed with an alanine spacer between the O-linked mannose moieties to investigate the impact of distance between the mannose units on receptor-mediated uptake and/or binding in APCs. Uptake studies performed on F4/80(+) and CD11c(+) cells showed significant uptake and/or binding for lipopeptides containing mannose, and also the lipopeptide without mannose when compared to the control peptides (peptide with no lipid and peptide with no mannose and no lipid). Furthermore, mannan inhibition assays demonstrated that uptake of the mannosylated and lipidated peptides was receptor mediated. To address the specificity of receptor uptake, surface plasmon resonance studies were performed using biacore technology and confirmed high affinity of the mannosylated and lipidated vaccine constructs toward the MR. These studies confirm that both mannose and lipid moieties play significant roles in receptor-mediated uptake on APCs, potentially facilitating vaccine development.

Characterization of the LP28 strain-specific exopolysaccharide biosynthetic gene cluster found in the whole circular genome of Pediococcus pentosaceus

We have previously isolated a lactic acid bacterium (LAB), Pediococcus pentosaceus LP28, from the longan fruit Euphoria longana. Since the plant-derived LAB strain produces an extracellular polysaccharide (EPS), in this study, we analyzed the chemical structure and the biosynthesizing genes for the EPS.The EPS, which was purified from the LP28 culture broth, was classified into acidic and neutral EPSs with a molecular mass of about 50kDa and 40kDa, respectively. The acidic EPS consisted of glucose, galactose, mannose, and N-acetylglucosamine moieties. Interestingly, since pyruvate residue was detected in the hydrolyzed acidic EPS, one of the four sugars may be modified with pyruvate. On the other hand, the neutral EPS consisted of glucose, mannose, and N-acetylglucosamine; pyruvate was scarcely detected in the polysaccharide molecule.As a first step to deduce the probiotic function of the EPS together with the biosynthesis, we determined the whole genome sequence of the LP28 strain, demonstrating that the genome is a circular DNA, which is composed of 1,774,865bp (1683 ORFs) with a GC content of 37.1%. We also found that the LP28 strain harbors a plasmid carrying 6 ORFs composed of 5366bp with a GC content of 36.5%. By comparing all of the genome sequences among the LP28 strain and four strains of P. pentosaceus reported previously, we found that 53 proteins in the LP28 strain display a similarity of less than 50% with those in the four P. pentosaceus strains. Significantly, 4 of the 53 proteins, which may be enzymes necessary for the EPS production on the LP28 strain, were absent in the other four P. pentosaceus strains and displayed less than 50% similarity with other LAB species. The EPS-biosynthetic gene cluster detected only in the LP28 genome consisted of 12 ORFs containing a priming enzyme, five glycosyltransferases, and a putative polysaccharide pyruvyltransferase.

Extracts from Flammulina velutipes inhibit the adhesion of pathogenic fungi to epithelial cells

Background:Recently, extracts from natural sources have been tested for their antifungal properties. In this aspect, Flammulina velutipes extracts possess a significant amount of branch-chained carbohydrates with mannose moieties that, hypothetically, can reduce the adhesion.Objective:In this study, we assessed the capacity of extracts from F. velutipes (wild-type AQF-1 and ATCC 34574 as the reference strain) to inhibit the adhesion of S. schenkii and C. albicans to epithelial cells.Materials and Methods:The aqueous extracts from F. velutipes strains were obtained by sonication, total carbohydrate and protein was analyzed by Dubois and Lowry methods respectively. Effect of the extracts (50, 100 and 150 μg/mL) on the fungi adhesion to host cells was evaluated after 1 h interaction, and the percentage of inhibition of adhesion was measured. After of interaction the cytoskeleton from cell was analyzed with phalloidin-FITC.Results:The extract from strain AQF-1 (50, 100 and 150 μg/mL) inhibited the adhesion of: S. schenkii in a dose-dependent manner (4.9, 7.5 and 12.7%, respectively) and C. albicans in a dose-independent manner (5.2%). The percentage of inhibition by extracts from the strain ATCC34574 at the same concentrations, shown that are dose independent for both fungi: 3.9% for S. schenkii and 2.6% for C. albicans.Conclusion:The extracts from F. velutipes inhibit the adhesion of pathogenic fungi to host cells. The mechanism molecular is unknown; however, is probably an interaction between the polysaccharides from extracts with the fungi receptors. This aspect is currently analyzed.SUMMARY The yields of mycelium from two strains of F. velutipes and the extract from it were similar.Extracts from both strains have inhibited adhesion of S. schenkii and C. albicans to epithelial cells in vitro, but the extract from strain AQF-1 was more effective.The extracts have not prevented damage to epithelial cells caused by pathogenic fungi. Abbreviation Used: YPG: Yeast peptone glucose, DMEM: Dulbecco's Modified Eagle's medium, FITC: Fluorescein isothiocyanate

The Extracellular Wall-Bound β-N-Acetylglucosaminidase from Lactobacillus casei Is Involved in the Metabolism of the Human Milk Oligosaccharide Lacto-N-Triose.

Human milk oligosaccharides (HMOs) are considered to play a key role in establishing and maintaining the infant gut microbiota. Lacto-N-triose forms part of both type 1 and type 2 HMOs and also of the glycan moieties of glycoproteins. Upstream of the previously characterized gene cluster involved in lacto-N-biose and galacto-N-biose metabolism from Lactobacillus casei BL23, there are two genes, bnaG and manA, encoding a β-N-acetylglucosaminidase precursor and a mannose-6-phosphate isomerase, respectively. In this work, we show that L. casei is able to grow in the presence of lacto-N-triose as a carbon source. Inactivation of bnaG abolished the growth of L. casei on this oligosaccharide, demonstrating that BnaG is involved in its metabolism. Interestingly, whole cells of a bnaG mutant were totally devoid of β-N-acetylglucosaminidase activity, suggesting that BnaG is an extracellular wall-attached enzyme. In addition to hydrolyzing lacto-N-triose into N-acetylglucosamine and lactose, the purified BnaG enzyme also catalyzed the hydrolysis of 3'-N-acetylglucosaminyl-mannose and 3'-N-acetylgalactosaminyl-galactose. L. casei can be cultured in the presence of 3'-N-acetylglucosaminyl-mannose as a carbon source, but, curiously, the bnaG mutant strain was not impaired in its utilization. These results indicate that the assimilation of 3'-N-acetylglucosaminyl-mannose is independent of BnaG. Enzyme activity and growth analysis with a manA-knockout mutant showed that ManA is involved in the utilization of the mannose moiety of 3'-N-acetylglucosaminyl-mannose. Here we describe the physiological role of a β-N-acetylglucosaminidase in lactobacilli, and it supports the metabolic adaptation of L. casei to the N-acetylglucosaminide-rich gut niche.

Development and Characterization of Nanoembedded Microparticles for Pulmonary Delivery of Antitubercular Drugs against Experimental Tuberculosis.

The foremost objective of the present research study was to develop and evaluate the potential of rifampicin (RIF) and isoniazid (INH) loaded spray dried nanoembedded microparticles against experimental tuberculosis (TB). In this study, RIF-INH loaded various formulations (chitosan, guar gum, mannan, and guar gum coated chitosan) were prepared by spray drying and characterized on the basis of in vitro as well as in vivo studies. Results showed that guar gum spray dried particles showed uniform size distribution with smooth surface as compare to mannan formulations. Guar gum batches exhibited excellent flow ability attributed to their optimum moisture content and uniform size distribution. The drug release showed the biphasic pattern of release, i.e., initial burst followed by a sustained release pattern. The preferential uptake of guar gum coated formulations suggested the presence and selective uptake capability of mannose moiety to the specific cell surface of macrophages. In vivo lung distribution study showed that guar gum coated chitosan (GCNP) batches demonstrated prolonged residence at the target site and thereby improve the therapeutic utility of drug with a significant reduction in systemic toxicity. Optimized drug loaded GCNP formulation has resulted in almost 5-fold reduction of the number of bacilli as compared to control group. Histopathology study also demonstrated that none of the treated groups show any evidence of lung tissue abnormality. Hence, GCNPs could be a promising carrier for selective delivery of antitubercular drugs to alveolar macrophages with the interception of minimal side effects, for efficient management of TB.

Abstract 5026: Tumor associated targeting with Manocept: HIV associated Kaposi's sarcoma as a model system

Abstract Introduction Inflammation appears to play a critical role in tumor development of HIV-associated Kaposi's sarcoma (KS). Specifically, emerging data show that KS tumor cells that co-express various macrophage (MO) antigens become resistant to current anti-viral therapies used to treat KS and AIDS. MOs also are a known source of KS tumor cell growth factors and substantial evidence suggests that tumor associated macrophages (TAMs) may represent a reservoir for HIV and its evolved retroviral variants. The MO pool driving these two pathological pathways share a common element rooted in the MOs, the CD206 human macrophage mannose receptor. Manocept, a molecular targeting agent, binds and enters MOs via pinocytosis of holo-CD206, providing a cell portal for the evaluation of Manocept as a MO and KS targeting agent. Methods Manocept was prepared as a synthetic molecule with a dextran backbone, and 12-20 mannose moieties. The reporter molecule (Cy3) was included as a fluorescent tracer for locating Manocept on and in MOs and KS tumor cells. Binding and localization Cy3-Manocept was assessed through intracellular visualization and flow cytometric quantitation of Cy3-Manocept binding and uptake using in vitro generation of monocyte-derived CD206+ MOs. The fresh HIV+ KS tumor tissue culture followed by immunofluorescence staining and confocal imaging was performed to confirm Cy3-Manocept uptake in KS tumor cells and TAMs. Results In vitro culture showed that Cy3-Manocept binds avidly to CD206 expressing MOs. Time course studies of increasing Cy3-Manocept concentrations confirmed continuous and ongoing uptake of Manocept into CD206+ MOs at 37°C. Fresh HIV+ KS tissue culture studies showed both Manocept uptake and CD206 staining of TAMs as well as KS tumor spindle cells (HHV8+ cells). Cy3-Manocept co-localized with CD206 in nearly all KS-associated cells expressing HHV8 and/or CD68 (Tissue MO marker), confirming that CD206 acts both as a target and Manocept concentrating receptor for TAMs and KS tumor cells. Conclusions Our results support the potential use of CD206 macrophage mannose receptor-targeted Manocept for imaging KS tumor cells, TAMs, and more importantly, for delivery of therapeutic/diagnostic agents capable of targeting all KS-associated cells including a potential MO reservoir for HIV. Citation Format: Rongzhen Zhang, Frederick O. Cope, Paige M. Bracci, Michael S. McGrath. Tumor associated targeting with Manocept: HIV associated Kaposi's sarcoma as a model system. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5026. doi:10.1158/1538-7445.AM2015-5026

Plasmon waveguide resonance for sensing glycan–lectin interactions

Carbohydrate-modified interfaces have been shown to be valuable tools for the study of protein–glycan recognition events. Label-free approache such as plasmonic based techniques are particularly attractive. This paper describes a new analytical platform for the sensitive and selective screening of carbohydrate–lectin interactions using plasmon waveguide resonance. Planar optical waveguides (POW), consisting of glass prisms coated with silver (50nm) and silica (460nm) layers were derivatized with mannose or lactose moieties. The specific association of the resulting interface with selected lectins was assessed by following the changes in its plasmonic response. The immobilization strategy investigated in this work is based on the formation of a covalent bond between propargyl-functionalized glycans and surface-linked azide groups via a Cu(I) “click” chemistry. Optimization of the surface architecture through the introduction of an oligo(ethylene glycol) spacer between the plasmonic surface and the glycan ligands provided an interface which allowed screening of glycan–lectin interactions in a highly selective manner. The limit of detection (LOD) of this method for this particular application was found to be in the subnanomolar range (0.5nM), showing it to constitute a promising analytical platform for future development and use in a pharmaceutical or biomedical setting.

Surface functionalization of polymeric nanospheres modulates macrophage activation: relevance in leishmaniasis therapy.

To characterize the production and application of carbohydrate functionalized poly(D,L-lactide-co-glycolide) (PLGA) nanospheres as immune-modulatory mediators in the treatment of visceral leishmaniasis (VL). PLGA nanospheres were prepared by nanoprecipitation and surface functionalized with mannose, mannan or mannosamine moieties using a carbodiimide reaction. Flow cytometry and fluorescence microscopy revealed the interaction of these nanospheres with macrophages. The nanocarriers were taken up by murine primary macrophages using clathrin-mediated endocytosis. Co-culture of macrophages with carbohydrate-functionalized nanospheres led to their activation and production of pro-inflammatory cytokines. One dose of amphotericin B-loaded on mannan-functionalized nanospheres resulted in an efficacy VL therapy. This approach provides a promising therapy for VL and a new therapeutic nanoplatform for obligate intracellular pathogens.

Biodegradable micelles capable of mannose-mediated targeted drug delivery to cancer cells.

A targeted micellar drug delivery system is developed from a biocompatible and biodegradable amphiphilic polyester, poly(Lac-OCA)-b-(poly(Tyr(alkynyl)-OCA)-g-mannose) (PLA-b-(PTA-g-mannose), that is synthesized via controlled ring-opening polymerization of O-carboxyanhydride (OCA) and highly efficient "Click" chemistry. Doxorubicin (DOX), a model lipophilic anticancer drug, can be effectively encapsulated into the micelles, and the mannose moiety allows active targeting of the micelles to cancer cells that specifically express mannose receptors, which thereafter enhances the anticancer efficiency of the drug. Comprised entirely of biodegradable and biocompatible polyesters, this micellar system demonstrates promising potentials for targeted drug delivery and cancer therapy.

New fluorescent analogs of bacterial undecaprenyldiphosphate galactose

A synthesis of four new analogs of bacterial undecaprenyldiphosphate galactose, in which the oligoisoprenoid moiety is replaced with a linear hydrocarbon chain, was accomplished. These compounds contain a fluorescent anthracenyl group at the ω-end of the lipophilic chain variable in length. A comparative analysis of their ability to serve as substrates-acceptors of the mannose moiety in the enzymatic reactions catalyzed by mannosyltransferase from bacteria Salmonella newport cell membranes was performed.

A chitin-like component on sclerotic cells of Fonsecaea pedrosoi inhibits Dectin-1-mediated murine Th17 development by masking β-glucans.

Fonsecaea pedrosoi (F. pedrosoi), a major agent of chromoblastomycosis, has been shown to be recognized primarily by C-type lectin receptors (CLRs) in a murine model of chromoblastomycosis. Specifically, the β-glucan receptor, Dectin-1, mediates Th17 development and consequent recruitment of neutrophils, and is evidenced to have the capacity to bind to saprophytic hyphae of F. pedrosoi in vitro. However, when embedded in tissue, most etiological agents of chromoblastomycosis including F. pedrosoi will transform into the sclerotic cells, which are linked to the greatest survival of melanized fungi in tissue. In this study, using immunocompetent and athymic (nu/nu) murine models infected subcutaneously or intraperitoneally with F. pedrosoi, we demonstrated that T lymphocytes play an active role in the resolution of localized footpad infection, and there existed a significantly decreased expression of Th17-defining transcription factor Rorγt and inefficient recruitment of neutrophils in chronically infected spleen where the inoculated mycelium of F. pedrosoi transformed into the sclerotic cells. We also found that Dectin-1-expressing histocytes and neutrophils participated in the enclosure of transformed sclerotic cells in the infectious foci. Furthermore, we induced the formation of sclerotic cells in vitro, and evidenced a significantly decreased binding capacity of human or murine-derived Dectin-1 to the induced sclerotic cells in comparison with the saprophytic mycelial forms. Our analysis of β-glucans-masking components revealed that it is a chitin-like component, but not the mannose moiety on the sclerotic cells, that interferes with the binding of β-glucans by human or murine Dectin-1. Notably, we demonstrated that although Dectin-1 contributed to the development of IL-17A-producing CD3+CD4+ murine splenocytes upon in vitro-stimulation by saprophytic F. pedrosoi, the masking effect of chitin components partly inhibited Dectin-1-mediated Th17 development upon in vitro-stimulation by induced sclerotic cells. Therefore, these findings extend our understanding of the chronicity of chromoblastomycosis.

A secreted protein with plant-specific cysteine-rich motif functions as a mannose-binding lectin that exhibits antifungal activity.

Plants have a variety of mechanisms for defending against plant pathogens and tolerating environmental stresses such as drought and high salinity. Ginkbilobin2 (Gnk2) is a seed storage protein in gymnosperm that possesses antifungal activity and a plant-specific cysteine-rich motif (domain of unknown function26 [DUF26]). The Gnk2-homologous sequence is also observed in an extracellular region of cysteine-rich repeat receptor-like kinases that function in response to biotic and abiotic stresses. Here, we report the lectin-like molecular function of Gnk2 and the structural basis of its monosaccharide recognition. Nuclear magnetic resonance experiments showed that mannan was the only yeast (Saccharomyces cerevisiae) cell wall polysaccharide that interacted with Gnk2. Gnk2 also interacted with mannose, a building block of mannan, with a specificity that was similar to those of mannose-binding legume lectins, by strictly recognizing the configuration of the hydroxy group at the C4 position of the monosaccharide. The crystal structure of Gnk2 in complex with mannose revealed that three residues (asparagine-11, arginine-93, and glutamate-104) recognized mannose by hydrogen bonds, which defined the carbohydrate-binding specificity. These interactions were directly related to the ability of Gnk2 to inhibit the growth of fungi, including the plant pathogenic Fusarium spp., which were disrupted by mutation of arginine-93 or the presence of yeast mannan in the assay system. In addition, Gnk2 did not inhibit the growth of a yeast mutant strain lacking the α1,2-linked mannose moiety. These results provide insights into the molecular basis of the DUF26 protein family.

Mapping lymph nodes in cancer management - role of (99m)Tc-tilmanocept injection.

Two decades ago, lymphatic mapping of sentinel lymph nodes (SLN) was introduced into surgical cancer management and was termed sentinel node navigated surgery. Although this technique is now routinely performed in the management of breast cancer and malignant melanoma, it is still under investigation for use in other cancers. The radioisotope technetium (99mTc) and vital blue dyes are among the most widely used enhancers for SLN mapping, although near-infrared fluorescence imaging of indocyanine green is also becoming more commonly used. 99mTc-tilmanocept is a new synthetic radioisotope with a relatively small molecular size that was specifically developed for lymphatic mapping. Because of its small size, 99mTc-tilmanocept quickly migrates from its site of injection and rapidly accumulates in the SLN. The mannose moieties of 99mTc-tilmanosept facilitate its binding to mannose receptors (CD206) expressed in reticuloendothelial cells of the SLN. This binding prevents transit to second-echelon lymph nodes. In Phase III trials of breast cancer and malignant melanoma, and Phase II trials of other malignancies, 99mTc-tilmanocept had superior identification rates and sensitivity compared with blue dye. Trials comparing 99mTc-tilmanocept with other 99mTc-based agents are required before it can be routinely used in clinical settings.

Antigenic characterization of Enteromyxum leei (Myxozoa: Myxosporea)

Enteromyxum leei, an intestinal myxozoan parasite affecting a wide range of fish, was partially purified, and the immunogenic composition of its glycoproteins as well as the proteolytic activity were studied. Parasite extracts, mainly containing spores, were separated by SDS-PAGE, and thereafter, immunoblots were carried out with a polyclonal antiserum (Pab) raised against E. leei. Periodic acid/Schiff staining of gels, periodate- and Proteinase K-treated Western blots and Lectin blots were performed to analyse the terminal carbohydrate composition of the parasite's antigens. Additionally, the cross-reaction of the parasite extracts with a Pab raised against the polar filament of the myxozoan Myxobolus pendula was studied. Both Pabs detected proteic epitopes on antigenic proteins and glycoproteins of E. leei, ranging between 15 and 280 kDa. In particular, 2 glycoproteic bands (15 and 165 kDa), immunoreactive to both Pabs and with glucose and mannose moieties, could correspond to common antigens shared among myxozoans. The 165 kDa band also presented galactose, N-acetyl-galactosamine and N-acetyl-glucosamine, pointing to its possible origin on chitin-built spore valves and to its possible involvement in host-parasite interactions. The molecular weight of the 15 kDa glycoproteic antigen matches that of minicollagen, a cnidarian-specific protein of nematocysts with a myxozoan homologue. Several proteases with apparent molecular weights ranging between 43 and 245 kDa were found in zymographies of E. leei extracts, and these may have a potential role in the parasite's pathogenesis. This is a useful approach for further studies to detect targets for antiparasitic therapy.

Stereoselective total synthesis of acremomannolipin A and its anomer, the potent calcium signal modulators with a novel glycolipid structure: role of the stereochemistry at the anomeric center on the activity

A full account of stereoselective total synthesis of a novel glycolipid, acremomannolipin A (1), the potent calcium signal modulator isolated from Acremonium strictum, by employing the stereoselective β-mannosylation of 4,6-O-benzylidene-protected mannosyl sulfoxide with d-mannitol as the key reaction is described. The α-anomer (epi-1) of 1 was also synthesized selectively. The calcium modulating activity was reduced upon inversion of the configuration at the anomeric center, indicating that the β-configuration of the mannose moiety is preferable for the activity.