Science.gov

Sample records for intact polysaccharide capsule

  1. Campylobacter Polysaccharide Capsules: Virulence and Vaccines

    PubMed Central

    Guerry, Patricia; Poly, Frédéric; Riddle, Mark; Maue, Alexander C.; Chen, Yu-Han; Monteiro, Mario A.

    2012-01-01

    Campylobacter jejuni remains a major cause of bacterial diarrhea worldwide and is associated with numerous sequelae, including Guillain Barré Syndrome, inflammatory bowel disease, reactive arthritis, and irritable bowel syndrome. C. jejuni is unusual for an intestinal pathogen in its ability to coat its surface with a polysaccharide capsule (CPS). These capsular polysaccharides vary in sugar composition and linkage, especially those involving heptoses of unusual configuration and O-methyl phosphoramidate linkages. This structural diversity is consistent with CPS being the major serodeterminant of the Penner scheme, of which there are 47 C. jejuni serotypes. Both CPS expression and expression of modifications are subject to phase variation by slip strand mismatch repair. Although capsules are virulence factors for other pathogens, the role of CPS in C. jejuni disease has not been well defined beyond descriptive studies demonstrating a role in serum resistance and for diarrhea in a ferret model of disease. However, perhaps the most compelling evidence for a role in pathogenesis are data that CPS conjugate vaccines protect against diarrheal disease in non-human primates. A CPS conjugate vaccine approach against this pathogen is intriguing, but several questions need to be addressed, including the valency of CPS types required for an effective vaccine. There have been numerous studies of prevalence of CPS serotypes in the developed world, but few studies from developing countries where the disease incidence is higher. The complexity and cost of Penner serotyping has limited its usefulness, and a recently developed multiplex PCR method for determination of capsule type offers the potential of a more rapid and affordable method. Comparative studies have shown a strong correlation of the two methods and studies are beginning to ascertain CPS-type distribution worldwide, as well as examination of correlation of severity of illness with specific CPS types. PMID:22919599

  2. Capsule of Cryptococcus neoformans grows by enlargement of polysaccharide molecules.

    PubMed

    Frases, Susana; Pontes, Bruno; Nimrichter, Leonardo; Viana, Nathan B; Rodrigues, Marcio L; Casadevall, Arturo

    2009-01-27

    The human pathogenic fungus Cryptococcus neoformans has a distinctive polysaccharide (PS) capsule that enlarges during infection. The capsule is essential for virulence, but the mechanism for capsular growth is unknown. In the present study, we used dynamic light scattering (LS) analysis of capsular PS and optical tweezers (OT) to explore the architecture of the capsule. Analysis of capsular PS from cells with small and large capsules by dynamic LS revealed a linear correlation between PS effective diameter and microscopic capsular diameter. This result implied that capsule growth was achieved by the addition of molecules with larger effective diameter, such that some molecules can span the entire diameter of the capsule. Measurement of polystyrene bead penetration of C. neoformans capsules by using OT techniques revealed that the outer regions were penetrable, but not the inner regions. Our results provide a mechanism for capsular enlargement based on the axial lengthening of PS molecules and suggest a model for the architecture of a eukaryotic microbial capsule.

  3. Capsule of Cryptococcus neoformans grows by enlargement of polysaccharide molecules

    PubMed Central

    Frases, Susana; Pontes, Bruno; Nimrichter, Leonardo; Viana, Nathan B.; Rodrigues, Marcio L.; Casadevall, Arturo

    2009-01-01

    The human pathogenic fungus Cryptococcus neoformans has a distinctive polysaccharide (PS) capsule that enlarges during infection. The capsule is essential for virulence, but the mechanism for capsular growth is unknown. In the present study, we used dynamic light scattering (LS) analysis of capsular PS and optical tweezers (OT) to explore the architecture of the capsule. Analysis of capsular PS from cells with small and large capsules by dynamic LS revealed a linear correlation between PS effective diameter and microscopic capsular diameter. This result implied that capsule growth was achieved by the addition of molecules with larger effective diameter, such that some molecules can span the entire diameter of the capsule. Measurement of polystyrene bead penetration of C. neoformans capsules by using OT techniques revealed that the outer regions were penetrable, but not the inner regions. Our results provide a mechanism for capsular enlargement based on the axial lengthening of PS molecules and suggest a model for the architecture of a eukaryotic microbial capsule. PMID:19164571

  4. Perforation forces of the intact porcine anterior lens capsule.

    PubMed

    Ullrich, Franziska; Lussi, Jonas; Felekis, Dimitrios; Michels, Stephan; Petruska, Andrew J; Nelson, Bradley J

    2016-09-01

    During the first step of cataract surgery, the lens capsule is perforated and a circular hole is created with a sharp instrument, a procedure called capsulorhexis. To develop automated systems that can assist ophthalmologists during capsulorhexis, the forces required must be quantified. This study investigates perforation forces of the central anterior lens capsule in porcine eyes, which are used as a conservative model for the human eye. A micro-mechanical characterisation method is presented that measures capsular bag perforation forces with a high precision positioning and high-resolution force sensing system. The force during perforation of the anterior lens capsule was measured with various sized needles and indentation speeds and is found to be 15-35mN. A bio-mechanical model is identified that describes an exponential correlation between indentation force and depth, indicating strain hardening behaviour of the porcine anterior lens capsule.

  5. Perforation forces of the intact porcine anterior lens capsule.

    PubMed

    Ullrich, Franziska; Lussi, Jonas; Felekis, Dimitrios; Michels, Stephan; Petruska, Andrew J; Nelson, Bradley J

    2016-09-01

    During the first step of cataract surgery, the lens capsule is perforated and a circular hole is created with a sharp instrument, a procedure called capsulorhexis. To develop automated systems that can assist ophthalmologists during capsulorhexis, the forces required must be quantified. This study investigates perforation forces of the central anterior lens capsule in porcine eyes, which are used as a conservative model for the human eye. A micro-mechanical characterisation method is presented that measures capsular bag perforation forces with a high precision positioning and high-resolution force sensing system. The force during perforation of the anterior lens capsule was measured with various sized needles and indentation speeds and is found to be 15-35mN. A bio-mechanical model is identified that describes an exponential correlation between indentation force and depth, indicating strain hardening behaviour of the porcine anterior lens capsule. PMID:27254279

  6. Capsular polysaccharide production in Enterococcus faecalis and contribution of CpsF to capsule serospecificity.

    PubMed

    Thurlow, Lance R; Thomas, Vinai Chittezham; Hancock, Lynn E

    2009-10-01

    Many bacterial species produce capsular polysaccharides that contribute to pathogenesis through evasion of the host innate immune system. The gram-positive pathogen Enterococcus faecalis was previously reported to produce one of four capsule serotypes (A, B, C, or D). Previous studies describing the four capsule serotypes of E. faecalis were based on immunodetection methods; however, the underlying genetics of capsule production did not fully support these findings. Previously, it was shown that capsule production for serotype C (Maekawa type 2) was dependent on the presence of nine open reading frames (cpsC to cpsK). Using a novel genetic system, we demonstrated that seven of the nine genes in the cps operon are essential for capsule production, indicating that serotypes A and B do not make a capsular polysaccharide. In support of this observation, we showed that serotype C and D capsule polysaccharides mask lipoteichoic acid from detection by agglutinating antibodies. Furthermore, we determined that the genetic basis for the difference in antigenicity between serotypes C and D is the presence of cpsF in serotype C strains. High-pH anion-exchange chromatography with pulsed amperometric detection analysis of serotype C and D capsules indicated that cpsF is responsible for glucosylation of serotype C capsular polysaccharide in E. faecalis.

  7. Capsules of Streptococcus pneumoniae and other bacteria: paradigms for polysaccharide biosynthesis and regulation.

    PubMed

    Yother, Janet

    2011-01-01

    Capsular polysaccharides and exopolysaccharides play critical roles in bacterial survival strategies, and they can have important medical and industrial applications. An immense variety of sugars and glycosidic linkages leads to an almost unlimited diversity of potential polysaccharide structures. This diversity is reflected in the large number of serologically and chemically distinct polysaccharides that have been identified among both gram-positive and gram-negative bacteria. Despite this diversity, however, the genetic loci and mechanisms responsible for polysaccharide biosynthesis exhibit conserved features and can be classified into a small number of groups. In Streptococcus pneumoniae, capsule synthesis occurs by one of two distinct mechanisms that involve the polymerization of either individual sugars in a processive reaction (synthase dependent) or discrete repeat units in a nonprocessive reaction (Wzy dependent). Characterization of these systems has provided novel insights that are applicable to polymers synthesized by many gram-positive and gram-negative bacteria, as well as eukaryotes.

  8. Kingella kingae Expresses Four Structurally Distinct Polysaccharide Capsules That Differ in Their Correlation with Invasive Disease

    PubMed Central

    Porsch, Eric A.; Seed, Patrick C.; Heiss, Christian; Naran, Radnaa; Amit, Uri; Yagupsky, Pablo; Azadi, Parastoo; St. Geme, Joseph W.

    2016-01-01

    Kingella kingae is an encapsulated gram-negative organism that is a common cause of osteoarticular infections in young children. In earlier work, we identified a glycosyltransferase gene called csaA that is necessary for synthesis of the [3)-β-GalpNAc-(1→5)-β-Kdop-(2→] polysaccharide capsule (type a) in K. kingae strain 269–492. In the current study, we analyzed a large collection of invasive and carrier isolates from Israel and found that csaA was present in only 47% of the isolates. Further examination of this collection using primers based on the sequence that flanks csaA revealed three additional gene clusters (designated the csb, csc, and csd loci), all encoding predicted glycosyltransferases. The csb locus contains the csbA, csbB, and csbC genes and is associated with a capsule that is a polymer of [6)-α-GlcpNAc-(1→5)-β-(8-OAc)Kdop-(2→] (type b). The csc locus contains the cscA, cscB, and cscC genes and is associated with a capsule that is a polymer of [3)-β-Ribf-(1→2)-β-Ribf-(1→2)-β-Ribf-(1→4)-β-Kdop-(2→] (type c). The csd locus contains the csdA, csdB, and csdC genes and is associated with a capsule that is a polymer of [P-(O→3)[β-Galp-(1→4)]-β-GlcpNAc-(1→3)-α-GlcpNAc-1-] (type d). Introduction of the csa, csb, csc, and csd loci into strain KK01Δcsa, a strain 269–492 derivative that lacks the native csaA gene, was sufficient to produce the type a capsule, type b capsule, type c capsule, and type d capsule, respectively, indicating that these loci are solely responsible for determining capsule type in K. kingae. Further analysis demonstrated that 96% of the invasive isolates express either the type a or type b capsule and that a disproportionate percentage of carrier isolates express the type c or type d capsule. These results establish that there are at least four structurally distinct K. kingae capsule types and suggest that capsule type plays an important role in promoting K. kingae invasive disease. PMID:27760194

  9. Recombination in Streptococcus pneumoniae Lineages Increase with Carriage Duration and Size of the Polysaccharide Capsule

    PubMed Central

    Andam, Cheryl P.; Harris, Simon R.; Cornick, Jennifer E.; Yang, Marie; Bricio-Moreno, Laura; Kamng’ona, Arox W.; French, Neil; Heyderman, Robert S.; Kadioglu, Aras; Everett, Dean B.; Bentley, Stephen D.

    2016-01-01

    ABSTRACT Streptococcus pneumoniae causes a high burden of invasive pneumococcal disease (IPD) globally, especially in children from resource-poor settings. Like many bacteria, the pneumococcus can import DNA from other strains or even species by transformation and homologous recombination, which has allowed the pneumococcus to evade clinical interventions such as antibiotics and pneumococcal conjugate vaccines (PCVs). Pneumococci are enclosed in a complex polysaccharide capsule that determines the serotype; the capsule varies in size and is associated with properties including carriage prevalence and virulence. We determined and quantified the association between capsule and recombination events using genomic data from a diverse collection of serotypes sampled in Malawi. We determined both the amount of variation introduced by recombination relative to mutation (the relative rate) and how many individual recombination events occur per isolate (the frequency). Using univariate analyses, we found an association between both recombination measures and multiple factors associated with the capsule, including duration and prevalence of carriage. Because many capsular factors are correlated, we used multivariate analysis to correct for collinearity. Capsule size and carriage duration remained positively associated with recombination, although with a reduced P value, and this effect may be mediated through some unassayed additional property associated with larger capsules. This work describes an important impact of serotype on recombination that has been previously overlooked. While the details of how this effect is achieved remain to be determined, it may have important consequences for the serotype-specific response to vaccines and other interventions. PMID:27677790

  10. Evidence for a role of the polysaccharide capsule transport proteins in pertussis pathogenesis.

    PubMed

    Hoo, Regina; Lam, Jian Hang; Huot, Ludovic; Pant, Aakanksha; Li, Rui; Hot, David; Alonso, Sylvie

    2014-01-01

    Polysaccharide (PS) capsules are important virulence determinants for many bacterial pathogens. Bordetella pertussis, the agent of whooping cough, produces a surface associated microcapsule but its role in pertussis pathogenesis remained unknown. Here we showed that the B. pertussis capsule locus is expressed in vivo in murine lungs and that absence of the membrane-associated protein KpsT, involved in the transport of the PS polymers across the envelope, but not the surface-exposed PS capsule itself, affects drastically B. pertussis colonization efficacy in mice. Microarray analysis revealed that absence of KpsT in B. pertussis resulted in global down-regulation of gene expression including key virulence genes regulated by BvgA/S, the master two-component system. Using a BvgS phase-locked mutant, we demonstrated a functional link between KpsT and BvgA/S-mediated signal transduction. Whereas pull-down assays do not support physical interaction between BvgS sensor and any of the capsule locus encoded proteins, absence of KpsT impaired BvgS oligomerization, necessary for BvgS function. Furthermore, complementation studies indicated that instead of KpsT alone, the entire PS capsule transport machinery spanning the cell envelope likely plays a role in BvgS-mediated signal transduction. Our work thus provides the first experimental evidence of a role for a virulence-repressed gene in pertussis pathogenesis.

  11. Evidence for a Role of the Polysaccharide Capsule Transport Proteins in Pertussis Pathogenesis

    PubMed Central

    Hoo, Regina; Lam, Jian Hang; Huot, Ludovic; Pant, Aakanksha; Li, Rui; Hot, David; Alonso, Sylvie

    2014-01-01

    Polysaccharide (PS) capsules are important virulence determinants for many bacterial pathogens. Bordetella pertussis, the agent of whooping cough, produces a surface associated microcapsule but its role in pertussis pathogenesis remained unknown. Here we showed that the B. pertussis capsule locus is expressed in vivo in murine lungs and that absence of the membrane-associated protein KpsT, involved in the transport of the PS polymers across the envelope, but not the surface-exposed PS capsule itself, affects drastically B. pertussis colonization efficacy in mice. Microarray analysis revealed that absence of KpsT in B. pertussis resulted in global down-regulation of gene expression including key virulence genes regulated by BvgA/S, the master two-component system. Using a BvgS phase-locked mutant, we demonstrated a functional link between KpsT and BvgA/S-mediated signal transduction. Whereas pull-down assays do not support physical interaction between BvgS sensor and any of the capsule locus encoded proteins, absence of KpsT impaired BvgS oligomerization, necessary for BvgS function. Furthermore, complementation studies indicated that instead of KpsT alone, the entire PS capsule transport machinery spanning the cell envelope likely plays a role in BvgS-mediated signal transduction. Our work thus provides the first experimental evidence of a role for a virulence-repressed gene in pertussis pathogenesis. PMID:25501560

  12. Coordinate regulation of glycan degradation and polysaccharide capsule biosynthesis by a prominent human gut symbiont.

    PubMed

    Martens, Eric C; Roth, Robyn; Heuser, John E; Gordon, Jeffrey I

    2009-07-01

    Bacteria in the distal human gut have evolved diverse abilities to metabolize complex glycans, including the capacity to degrade these compounds as nutrients and to assemble their component sugars into new polymers such as extracellular capsules. The human gut bacterium Bacteroides thetaiotaomicron is well endowed with the ability to metabolize both host- and diet-derived glycans. Its genome contains 88 different polysaccharide utilization loci (PULs) for complex glycan catabolism and eight different gene clusters for capsular polysaccharide biosynthesis. Here, we investigate one of the prominent mechanisms by which this gut symbiont regulates many PULs involved in host mucin O-glycan degradation; namely, transcriptional regulation via the concerted interactions of cell-envelope-localized TonB-dependent transporters, extra-cytoplasmic function sigma factors and anti-sigma factors, which participate together in a regulatory pathway termed trans-envelope signaling. Unexpectedly, we found that several different trans-envelope signaling switches involved in PUL-mediated O-glycan degradation also modulate capsular polysaccharide synthesis. A novel regulatory pathway, which is dependent on expression of O-glycan-targeting outer membrane proteins, governs this coordinated regulation of glycan catabolism and capsule synthesis. This latter finding provides a new link in the dynamic interplay between complex glycan metabolism, microbial physiology, and host responses that occurs during colonization of the gut.

  13. Effects of alga polysaccharide capsule shells on in-vivo bioavailability and disintegration

    NASA Astrophysics Data System (ADS)

    Li, Ting; Guo, Shuju; Ma, Lin; Yuan, Yi; Han, Lijun

    2012-01-01

    Gelatin has been used in hard capsule shells for more than a century, and some shortcomings have appeared, such as high moisture content and risk of transmitting diseases of animal origin to people. Based on available studies regarding gelatin and vegetable shells, we developed a new type of algal polysaccharide capsule (APPC) shells. To test whether our products can replace commercial gelatin shells, we measured in-vivo plasma concentration of 12 selected volunteers with a model drug, ibuprofen, using high performance liquid chromatography (HPLC), by calculating the relative bioavailability of APPC and Qualicaps® referenced to gelatin capsules and assessing bioequivalence of the three types of shells, and calculated pharmacokinetic parameters with the software DAS 2.0 (China). The results show that APPC shells possess bioequivalence with Qualicaps® and gelatin shells. Moreover, the disintegration behavior of four types of shells (APPC, Vegcaps®, Qualicaps® and gelatin shells) with the content of lactose and radioactive element (99mTc) was observed via gamma-scintigraphic images. The bioavailability and gamma-scintigraphic studies showed that APPC was not statistically different from other vegetable and gelatin capsule shells with respect to in-vivo behavior. Hence, it can be concluded that APPCs are exchangeable with other vegetable and gelatin shells.

  14. Cryptococcal xylosyltransferase 1 (Cxt1p) from Cryptococcus neoformans plays a direct role in the synthesis of capsule polysaccharides.

    PubMed

    Klutts, J Stacey; Doering, Tamara L

    2008-05-23

    The opportunistic yeast Cryptococcus neoformans causes serious disease in humans and expresses a prominent polysaccharide capsule that is required for its virulence. Little is known about how this capsule is synthesized. We previously identified a beta1,2-xylosyltransferase (Cxt1p) with in vitro enzymatic activity appropriate for involvement in capsule synthesis. Here, we investigate C. neoformans strains in which the corresponding gene has been deleted (cxt1Delta). Loss of CXT1 does not affect in vitro growth of the mutant cells or the general morphology of their capsules. However, NMR structural analysis of the two main capsule polysaccharides, glucuronoxylomannan (GXM) and galactoxylomannan (GalXM), showed that both were missing beta1,2-xylose residues. There was an approximately 30% reduction in the abundance of this residue in GXM in mutant compared with wild-type strains, and mutant GalXM was almost completely devoid of beta1,2-linked xylose. The GalXM from the mutant strain was also missing a beta1,3-linked xylose residue. Furthermore, deletion of CXT1 led to attenuation of cryptococcal growth in a mouse model of infection, suggesting that the affected xylose residues are important for normal host-pathogen interactions. Cxt1p is the first glycosyltransferase with a defined role in C. neoformans capsule biosynthesis, and cxt1Delta is the only strain identified to date with structural alterations of the capsule polysaccharide GalXM.

  15. Noncovalent association of protein and capsular polysaccharide on bacteria-sized latex beads as a model for polysaccharide-specific humoral immunity to intact gram-positive extracellular bacteria.

    PubMed

    Colino, Jesus; Duke, Leah; Snapper, Clifford M

    2013-09-15

    Intact Streptococcus pneumoniae expressing type 14 capsular polysaccharide (PPS14) and type III S. agalactiae containing a PPS14 core capsule identical to PPS14 exhibit noncovalent associations of PPS14 and bacterial protein, in contrast to soluble covalent conjugates of these respective Ags. Both bacteria and conjugates induce murine PPS14-specific IgG responses dependent on CD4⁺ T cells. Further, secondary immunization with conjugate and S. agalactiae, although not S. pneumoniae, results in a boosted response. However, in contrast to conjugate, PPS14-specific IgG responses to bacteria lack affinity maturation use the 44.1-idiotype and are dependent on marginal zone B cells. To better understand the mechanism underlying this dichotomy, we developed a minimal model of intact bacteria in which PPS14 and pneumococcal surface protein A (PspA) were stably attached to 1 μm (bacteria-sized) latex beads, but not directly linked to each other, in contrast to PPS14-PspA conjugate. Beads coated simultaneously with PPS14+[PspA], similar to conjugate, induced in mice boosted PPS14-specific IgG secondary responses, dependent on T cells and ICOS-dependent costimulation, and in which priming could be achieved with PspA alone. In contrast to conjugate, but similar to intact bacteria, the primary PPS14-specific IgG response to beads coated simultaneously with PPS14+[PspA] peaked rapidly, with the secondary response highly enriched for the 44.1-idiotype and lacking affinity maturation. These results demonstrate that noncovalent association in a particle, of polysaccharide and protein, recapitulates essential immunologic characteristics of intact bacteria that are distinct from soluble covalent conjugates of these respective Ags.

  16. Differential regulation of polysaccharide-specific antibody responses to isolated polysaccharides, conjugate vaccines, and intact Gram-positive versus Gram-negative extracellular bacteria.

    PubMed

    Snapper, Clifford M

    2016-06-24

    Bacterial capsular polysaccharides are major virulence factors and are key targets in a number of licensed anti-bacterial vaccines. Their major characteristics are their large molecular weight and expression of repeating antigenic epitopes that mediate multivalent B cell receptor cross-linking. In addition, since the majority of these antigens cannot associate with MHC-II they fail to recruit CD4+ T cell help and are referred to as T cell-independent antigens. In this review I will discuss a series of studies from my laboratory that have underscored the importance of understanding polysaccharide-specific antibody responses within the context in which the PS is expressed (i.e. in isolation, as a component of conjugate vaccines, and expressed naturally by intact bacteria). We have shown that multivalent B cell receptor crosslinking, as mediated by polysaccharides, uniquely determines the qualitative response of the B cell to subsequent stimuli, but by itself is insufficient to induce antibody secretion or class switching. For these latter events to occur, second signals must act in concert with primary signals derived from the B cell receptor. The co-expression of polysaccharide and protein within intact bacteria promotes recruitment of CD4+ T cell help for the associated PS-specific IgG response, in contrast to isolated polysaccharides. Further, the particulate nature of extracellular bacteria confers properties to the polysaccharide-specific IgG response that makes it distinct immunologically from soluble conjugate vaccines. Finally, the underlying biochemical and/or structural differences that distinguish Gram-positive and Gram-negative bacteria appear to play critical roles in differentially regulating the associated polysaccharide-specific IgG responses to these groups of pathogens. These studies have a number of implications for the understanding and future design of polysaccharide-based vaccines.

  17. Differential regulation of polysaccharide-specific antibody responses to isolated polysaccharides, conjugate vaccines, and intact Gram-positive versus Gram-negative extracellular bacteria.

    PubMed

    Snapper, Clifford M

    2016-06-24

    Bacterial capsular polysaccharides are major virulence factors and are key targets in a number of licensed anti-bacterial vaccines. Their major characteristics are their large molecular weight and expression of repeating antigenic epitopes that mediate multivalent B cell receptor cross-linking. In addition, since the majority of these antigens cannot associate with MHC-II they fail to recruit CD4+ T cell help and are referred to as T cell-independent antigens. In this review I will discuss a series of studies from my laboratory that have underscored the importance of understanding polysaccharide-specific antibody responses within the context in which the PS is expressed (i.e. in isolation, as a component of conjugate vaccines, and expressed naturally by intact bacteria). We have shown that multivalent B cell receptor crosslinking, as mediated by polysaccharides, uniquely determines the qualitative response of the B cell to subsequent stimuli, but by itself is insufficient to induce antibody secretion or class switching. For these latter events to occur, second signals must act in concert with primary signals derived from the B cell receptor. The co-expression of polysaccharide and protein within intact bacteria promotes recruitment of CD4+ T cell help for the associated PS-specific IgG response, in contrast to isolated polysaccharides. Further, the particulate nature of extracellular bacteria confers properties to the polysaccharide-specific IgG response that makes it distinct immunologically from soluble conjugate vaccines. Finally, the underlying biochemical and/or structural differences that distinguish Gram-positive and Gram-negative bacteria appear to play critical roles in differentially regulating the associated polysaccharide-specific IgG responses to these groups of pathogens. These studies have a number of implications for the understanding and future design of polysaccharide-based vaccines. PMID:27133879

  18. Polysaccharide capsule and sialic acid-mediated regulation promote biofilm-like intracellular bacterial communities during cystitis.

    PubMed

    Anderson, Gregory G; Goller, Carlos C; Justice, Sheryl; Hultgren, Scott J; Seed, Patrick C

    2010-03-01

    Uropathogenic Escherichia coli (UPEC) is the leading cause of urinary tract infections (UTIs). A murine UTI model has revealed an infection cascade whereby UPEC undergoes cycles of invasion of the bladder epithelium, intracellular proliferation in polysaccharide-containing biofilm-like masses called intracellular bacterial communities (IBC), and then dispersal into the bladder lumen to initiate further rounds of epithelial colonization and invasion. We predicted that the UPEC K1 polysaccharide capsule is a key constituent of the IBC matrix. Compared to prototypic E. coli K1 strain UTI89, a capsule assembly mutant had a fitness defect in functionally TLR4(+) and TLR4(-) mice, suggesting a protective role of capsule in inflamed and noninflamed hosts. K1 capsule assembly and synthesis mutants had dramatically reduced IBC formation, demonstrating the common requirement for K1 polysaccharide in IBC development. The capsule assembly mutant appeared dispersed in the cytoplasm of the bladder epithelial cells and failed to undergo high-density intracellular replication during later stages of infection, when the wild-type strain continued to form serial generations of IBC. Deletion of the sialic acid regulator gene nanR partially restored IBC formation in the capsule assembly mutant. These data suggest that capsule is necessary for efficient IBC formation and that aberrant sialic acid accumulation, resulting from disruption of K1 capsule assembly, produces a NanR-mediated defect in intracellular proliferation and IBC development. Together, these data demonstrate the complex but important roles of UPEC polysaccharide encapsulation and sialic acid signaling in multiple stages of UTI pathogenesis.

  19. Fluconazole Alters the Polysaccharide Capsule of Cryptococcus gattii and Leads to Distinct Behaviors in Murine Cryptococcosis

    PubMed Central

    Santos, Julliana Ribeiro Alves; Holanda, Rodrigo Assunção; Frases, Susana; Bravim, Mayara; Araujo, Glauber de S.; Santos, Patrícia Campi; Costa, Marliete Carvalho; Ribeiro, Maira Juliana Andrade; Ferreira, Gabriella Freitas; Baltazar, Ludmila Matos; Miranda, Aline Silva; Oliveira, Danilo Bretas; Santos, Carolina Maria Araújo; Fontes, Alide Caroline Lima; Gouveia, Ludmila Ferreira; Resende-Stoianoff, Maria Aparecida; Abrahão, Jonatas Santos; Teixeira, Antônio Lúcio; Paixão, Tatiane Alves; Souza, Danielle G.; Santos, Daniel Assis

    2014-01-01

    Cryptococcus gattii is an emergent human pathogen. Fluconazole is commonly used for treatment of cryptococcosis, but the emergence of less susceptible strains to this azole is a global problem and also the data regarding fluconazole-resistant cryptococcosis are scarce. We evaluate the influence of fluconazole on murine cryptococcosis and whether this azole alters the polysaccharide (PS) from cryptococcal cells. L27/01 strain of C. gattii was cultivated in high fluconazole concentrations and developed decreased drug susceptibility. This phenotype was named L27/01F, that was less virulent than L27/01 in mice. The physical, structural and electrophoretic properties of the PS capsule of L27/01F were altered by fluconazole. L27/01F presented lower antiphagocytic properties and reduced survival inside macrophages. The L27/01F did not affect the central nervous system, while the effect in brain caused by L27/01 strain began after only 12 hours. Mice infected with L27/01F presented lower production of the pro-inflammatory cytokines, with increased cellular recruitment in the lungs and severe pulmonary disease. The behavioral alterations were affected by L27/01, but no effects were detected after infection with L27/01F. Our results suggest that stress to fluconazole alters the capsule of C. gattii and influences the clinical manifestations of cryptococcosis. PMID:25392951

  20. Fluconazole alters the polysaccharide capsule of Cryptococcus gattii and leads to distinct behaviors in murine Cryptococcosis.

    PubMed

    Santos, Julliana Ribeiro Alves; Holanda, Rodrigo Assunção; Frases, Susana; Bravim, Mayara; Araujo, Glauber de S; Santos, Patrícia Campi; Costa, Marliete Carvalho; Ribeiro, Maira Juliana Andrade; Ferreira, Gabriella Freitas; Baltazar, Ludmila Matos; Miranda, Aline Silva; Oliveira, Danilo Bretas; Santos, Carolina Maria Araújo; Fontes, Alide Caroline Lima; Gouveia, Ludmila Ferreira; Resende-Stoianoff, Maria Aparecida; Abrahão, Jonatas Santos; Teixeira, Antônio Lúcio; Paixão, Tatiane Alves; Souza, Danielle G; Santos, Daniel Assis

    2014-01-01

    Cryptococcus gattii is an emergent human pathogen. Fluconazole is commonly used for treatment of cryptococcosis, but the emergence of less susceptible strains to this azole is a global problem and also the data regarding fluconazole-resistant cryptococcosis are scarce. We evaluate the influence of fluconazole on murine cryptococcosis and whether this azole alters the polysaccharide (PS) from cryptococcal cells. L27/01 strain of C. gattii was cultivated in high fluconazole concentrations and developed decreased drug susceptibility. This phenotype was named L27/01F, that was less virulent than L27/01 in mice. The physical, structural and electrophoretic properties of the PS capsule of L27/01F were altered by fluconazole. L27/01F presented lower antiphagocytic properties and reduced survival inside macrophages. The L27/01F did not affect the central nervous system, while the effect in brain caused by L27/01 strain began after only 12 hours. Mice infected with L27/01F presented lower production of the pro-inflammatory cytokines, with increased cellular recruitment in the lungs and severe pulmonary disease. The behavioral alterations were affected by L27/01, but no effects were detected after infection with L27/01F. Our results suggest that stress to fluconazole alters the capsule of C. gattii and influences the clinical manifestations of cryptococcosis.

  1. Fluconazole alters the polysaccharide capsule of Cryptococcus gattii and leads to distinct behaviors in murine Cryptococcosis.

    PubMed

    Santos, Julliana Ribeiro Alves; Holanda, Rodrigo Assunção; Frases, Susana; Bravim, Mayara; Araujo, Glauber de S; Santos, Patrícia Campi; Costa, Marliete Carvalho; Ribeiro, Maira Juliana Andrade; Ferreira, Gabriella Freitas; Baltazar, Ludmila Matos; Miranda, Aline Silva; Oliveira, Danilo Bretas; Santos, Carolina Maria Araújo; Fontes, Alide Caroline Lima; Gouveia, Ludmila Ferreira; Resende-Stoianoff, Maria Aparecida; Abrahão, Jonatas Santos; Teixeira, Antônio Lúcio; Paixão, Tatiane Alves; Souza, Danielle G; Santos, Daniel Assis

    2014-01-01

    Cryptococcus gattii is an emergent human pathogen. Fluconazole is commonly used for treatment of cryptococcosis, but the emergence of less susceptible strains to this azole is a global problem and also the data regarding fluconazole-resistant cryptococcosis are scarce. We evaluate the influence of fluconazole on murine cryptococcosis and whether this azole alters the polysaccharide (PS) from cryptococcal cells. L27/01 strain of C. gattii was cultivated in high fluconazole concentrations and developed decreased drug susceptibility. This phenotype was named L27/01F, that was less virulent than L27/01 in mice. The physical, structural and electrophoretic properties of the PS capsule of L27/01F were altered by fluconazole. L27/01F presented lower antiphagocytic properties and reduced survival inside macrophages. The L27/01F did not affect the central nervous system, while the effect in brain caused by L27/01 strain began after only 12 hours. Mice infected with L27/01F presented lower production of the pro-inflammatory cytokines, with increased cellular recruitment in the lungs and severe pulmonary disease. The behavioral alterations were affected by L27/01, but no effects were detected after infection with L27/01F. Our results suggest that stress to fluconazole alters the capsule of C. gattii and influences the clinical manifestations of cryptococcosis. PMID:25392951

  2. Localization of polysaccharides in isolated and intact cuticles of eucalypt, poplar and pear leaves by enzyme-gold labelling.

    PubMed

    Guzmán, Paula; Fernández, Victoria; García, María Luisa; Khayet, Mohamed; Fernández, Agustín; Gil, Luis

    2014-03-01

    The presence and characteristics of cuticle polysaccharides have been demonstrated by staining and spectroscopic methods, but their location in the cuticle remains unclear. Furthermore, according to the prevailing model, polysaccharides are believed to be restricted to the cuticular layer and absent in the cuticle proper. With the aim of gaining insight into cuticular ultra-structure focussing on polysaccharides, cellulose and pectins have been identified and located in the transversal sections of isolated and intact adaxial leaf cuticles of Eucalyptus globulus, Populus × canescens and Pyrus communis by means of enzyme gold-labelling (Au-cellulase, EC 3.2.1.4, and -pectinase, EC 3.2.1.15) and transmission electron microscopy (TEM). The structure of the interface between the cuticle and the cell wall underneath was observed to influence the process of enzymatic isolation of leaf cuticles. Cellulose and pectins were detected for the first time in enzymatically isolated cuticles, sometimes appearing closely underneath the epicuticular wax layer. The location and presence of polysaccharides in intact and isolated leaf cuticles may have multiple implications, such as when estimating the bi-directional transport of substances between plant organs and the surrounding environment, or when interpreting organ ontogeny. The results are discussed within a plant ontological and ecophysiological context.

  3. Characterisation of transmission Raman spectroscopy for rapid quantitative analysis of intact multi-component pharmaceutical capsules.

    PubMed

    Hargreaves, Michael D; Macleod, Neil A; Smith, Mark R; Andrews, Darren; Hammond, Stephen V; Matousek, Pavel

    2011-02-20

    A detailed characterisation of the performance of transmission Raman spectroscopy was performed from the standpoint of rapid quantitative analysis of pharmaceutical capsules using production relevant formulations comprising of active pharmaceutical ingredient (API) and 3 common pharmaceutical excipients. This research builds on our earlier studies that identified the unique benefits of transmission Raman spectroscopy compared to conventional Raman spectroscopy. These include the ability to provide bulk information of the content of capsules, thus avoiding the sub-sampling problem, and the suppression of interference from the capsule shell. This study demonstrates, for the first time, the technique's insensitivity to the amount of material held within the capsules. Different capsules sizes with different overall fill weights (100-400 mg) and capsule shell colours were assayed with a single calibration model developed using only one weight and size sample set (100 mg) to a relative error of typically <3%. The relative root mean square error of prediction of the concentration of API for the main sample set (nominal content 75%, w/w) was 1.5% with a 5s acquisition time. Models built using the same calibration set also predicted the 3 low level excipients with relative errors of 5-15%. The quantity of API was also predicted (with a relative error within ∼3%) using the same model for capsules prepared with different generations of API (i.e. API manufactured via different processes). The study provides further foundation blocks for the establishment of this emerging technique as a routine pharmaceutical analysis tool, capitalising on the inherently high chemical specificity of Raman spectroscopy and the non-invasive nature of the measurement. Ultimately, this technique has significant promise as a Process Analytical Technology (PAT) tool for online production application. PMID:20947277

  4. The S. aureus polysaccharide capsule and Efb-dependent fibrinogen shield act in concert to protect against phagocytosis

    PubMed Central

    Kuipers, Annemarie; Stapels, Daphne A. C.; Weerwind, Lleroy T.; Ko, Ya-Ping; Ruyken, Maartje; Lee, Jean C.; van Kessel, Kok P.M.; Rooijakkers, Suzan H. M.

    2016-01-01

    Staphylococcus aureus has developed many mechanisms to escape from human immune responses. In order to resist phagocytic clearance, S. aureus expresses a polysaccharide capsule, which effectively masks the bacterial surface and surface-associated proteins, such as opsonins, from recognition by phagocytic cells. Additionally, secretion of the Extracellular fibrinogen binding protein (Efb) potently blocks phagocytic uptake of the pathogen. Efb creates a fibrinogen shield surrounding the bacteria by simultaneously binding complement C3b and fibrinogen at the bacterial surface. By means of neutrophil phagocytosis assays with fluorescently labeled encapsulated serotype 5 (CP5) and serotype 8 (CP8) strains we now compare the immune-modulating function of these shielding mechanisms. Our data indicate that, in highly encapsulated S. aureus strains, the polysaccharide capsule is able to prevent phagocytic uptake at plasma concentrations <10%, but loses its protective ability at higher concentrations of plasma. Interestingly, Efb shows a strong inhibitory effect on both capsule-negative as well as encapsulated strains at all tested plasma concentrations. Furthermore our results suggest that both shielding mechanisms can exist simultaneously and collaborate to provide optimal protection against phagocytosis at a broad range of plasma concentrations. Since opsonizing antibodies will be shielded from recognition by either mechanism, incorporating both capsular polysaccharides and Efb in future vaccines could be of great importance. PMID:27112346

  5. Cryptococcal Xylosyltransferase 1 (Cxt1p) from Cryptococcus neoformans Plays a Direct Role in the Synthesis of Capsule Polysaccharides*S⃞

    PubMed Central

    Klutts, J. Stacey; Doering, Tamara L.

    2008-01-01

    The opportunistic yeast Cryptococcus neoformans causes serious disease in humans and expresses a prominent polysaccharide capsule that is required for its virulence. Little is known about how this capsule is synthesized. We previously identified a β1,2-xylosyltransferase (Cxt1p) with in vitro enzymatic activity appropriate for involvement in capsule synthesis. Here, we investigate C. neoformans strains in which the corresponding gene has been deleted (cxt1Δ). Loss of CXT1 does not affect in vitro growth of the mutant cells or the general morphology of their capsules. However, NMR structural analysis of the two main capsule polysaccharides, glucuronoxylomannan (GXM) and galactoxylomannan (GalXM), showed that both were missing β1,2-xylose residues. There was an ∼30% reduction in the abundance of this residue in GXM in mutant compared with wild-type strains, and mutant GalXM was almost completely devoid of β1,2-linked xylose. The GalXM from the mutant strain was also missing a β1,3-linked xylose residue. Furthermore, deletion of CXT1 led to attenuation of cryptococcal growth in a mouse model of infection, suggesting that the affected xylose residues are important for normal host-pathogen interactions. Cxt1p is the first glycosyltransferase with a defined role in C. neoformans capsule biosynthesis, and cxt1Δ is the only strain identified to date with structural alterations of the capsule polysaccharide GalXM. PMID:18347023

  6. Anterior migration of dexamethasone implant in a pseudophakic patient with intact posterior capsule.

    PubMed

    Kocak, Nilufer; Ozturk, Taylan; Karahan, Eyyup; Kaynak, Suleyman

    2014-11-01

    Intravitreal application of Ozurdex ® (Allergan, Inc., Irvine, CA, USA) which is a biodegradable, sustained-release dexamethasone implant has been reported to be effective in the treatment of macular edema. Migration of such implant into the anterior chamber has been recently described in cases without perfect zonular or the posterior capsular integrity. Herein, we report the first case with anterior migration of Ozurdex ® implant that mislocated just behind the intraocular lens (IOL) in an intact capsular bag. It is thought that such implant migrated anteriorly towards into the posterior chamber through weak zonules as the present case had a medical history of uneventful phacoemulsification surgery with the implantation of posterior chamber IOL. However, the migrated implant was well tolerated since there was no sign of the corneal complication, rise in intraocular pressure, and anterior chamber reaction. Close follow-up was scheduled to find out any signs of anterior segment pathology. Meanwhile dexamethasone implant completely degraded at the 4 th month of postoperative follow-up. PMID:25494252

  7. Mechanisms underlying in vivo polysaccharide-specific immunoglobulin responses to intact extracellular bacteria.

    PubMed

    Snapper, Clifford M

    2012-04-01

    Polysaccharides (PS) have historically been viewed as T cell-independent antigens. However, in this paper I propose a new concept, based on substantial data from my laboratory over the previous 10 years, that during infections with PS-encapsulated extracellular bacteria, PS-specific IgG responses are largely CD4(+) T cell dependent. Thus, capsular PS is typically encountered by the immune system covalently attached to the underlying subcapsular bacterial domain. I speculate that noncovalent association of PS with immunogenic proteins within the bacterial particle leads to recruitment of protein-specific CD4(+) T cell help for the anti-PS response. However, differences in the composition and/or structure of the subcapsular domain of different extracellular bacteria may result in distinct anti-PS responses as well as differential effects on the immune response to coimmunizing soluble antigens. CD4(+) T cell help for IgG anti-PS responses during infections with extracellular bacteria is likely to promote opsonic clearance of these rapidly growing pathogens. However, the expression of immunosuppressive components by certain bacteria may also serve to dampen such responses.

  8. Inflammatory Monocytes Are Critical for Induction of a Polysaccharide-Specific Antibody Response to an Intact Bacterium

    PubMed Central

    Chen, Quanyi

    2013-01-01

    Although inflammatory monocytes (IM) (CD11b+Ly6Chi cells) have been shown to play important roles in cell-mediated host protection against intracellular bacteria, protozoans, and fungi, their potential impact on humoral immune responses to extracellular bacteria are unknown. IM, localized largely to the splenic marginal zone of naive CD11b–diphtheria toxin (DT) receptor bone marrow–chimeric mice were selectively depleted following treatment with DT, including no reduction of CD11b+ peritoneal B cells. Depletion of IM resulted in a marked reduction in the polysaccharide (PS)-specific, T cell–independent IgM, and T cell–dependent IgG responses to intact, heat-killed Streptococcus pneumoniae with no effect on the associated S. pneumoniae protein–specific IgG response or on the PS- and protein-specific IgG responses to a soluble pneumococcal conjugate vaccine. IM acted largely within the first 48 h following the initiation of the immune response to S. pneumoniae to induce the subsequent production of PS-specific IgM and IgG. Adoptive transfer of highly purified IM from wild-type mice into DT-treated CD11b–DT receptor mice completely restored the defective PS-specific Ig response to S. pneumoniae. IM were phenotypically and functionally distinct from circulating CD11b+CD11clowLy6G/C cells (immature blood dendritic cells), previously described to play a role in Ig responses to S. pneumoniae, in that they were CD11c− as well as Ly6Chi and did not internalize injected S. pneumoniae during the early phase of the response. These data are the first, to our knowledge, to establish a critical role for IM in the induction of an Ig response to an intact extracellular bacterium. PMID:23269244

  9. Expression of a Uniquely Regulated Extracellular Polysaccharide Confers a Large-Capsule Phenotype to Bacteroides fragilis▿

    PubMed Central

    Chatzidaki-Livanis, Maria; Coyne, Michael J.; Roche-Hakansson, Hazeline; Comstock, Laurie E.

    2008-01-01

    Bacteroides fragilis synthesizes eight distinct capsular polysaccharides, more than any described bacterium outside the order Bacteroidales. Here, we show that this organism also produces a high-molecular-weight extracellular polysaccharide (EPS). Expression of the EPS results in the formation of a large polysaccharide layer around the bacteria which prevents them from forming a tight pellet upon centrifugation and from entering a Percoll density gradient. Like expression of the capsular polysaccharides, expression of the EPS is phase variable and dictated by DNA inversion of its promoter. EPS expression is regulated at one level by the DNA invertase Tsr19, which is encoded by a gene immediately upstream of the EPS locus and inverts the EPS promoter, causing an on or off phenotype. Expression of the EPS is also regulated at another level, which dictates the amount of EPS produced. By analyzing a panel of tsr19 deletion mutants, we found that the number of inverted repeats (IRs) flanking the promoter is variable. Transcription into the EPS genes is greater in mutants with a single IR between the promoter and the downstream EPS genes than in mutants with more than one IR in this region, correlating with the synthesis of more EPS. By analyzing the relative orientations of the EPS promoter of bacteria obtained from human fecal samples, we showed that both DNA inversion and variation in the number of IRs are active processes of B. fragilis in the endogenous human intestinal ecosystem. PMID:18039760

  10. Ultrastructural localization of capsules, cell wall polysaccharide, cell wall proteins, and F antigen in pneumococci.

    PubMed Central

    Skov Sørensen, U B; Blom, J; Birch-Andersen, A; Henrichsen, J

    1988-01-01

    The localization of pneumococcal capsular and cell wall antigens was examined by immunoelectron microscopy. C polysaccharide (C-Ps), a common component of all pneumococci, was uniformly distributed on both the inside and outside of the cell walls. The thickness of the C-Ps varied with the strain. Encapsulated strains were covered by varied amounts of capsular polysaccharide concealing the C-Ps of the bacteria so as to render it inaccessible to anti-C-Ps antibodies. In addition to C-Ps, protein antigens were demonstrable on the surface of nonencapsulated pneumococci. The proteins were not masked by the C-Ps layer. An extra layer on the cell walls was conspicuous on electron micrographs of both rough and encapsulated pneumococci. The nature of this extra layer has not been disclosed. F antigen, another common antigen of pneumococci, was uniformly distributed on the surface of the plasma membranes. During the course of the experimental work a reproducible method of gold labeling immunoglobulins was developed. Images PMID:3397179

  11. The pneumococcal polysaccharide capsule and pneumolysin differentially affect CXCL8 and IL-6 release from cells of the upper and lower respiratory tract.

    PubMed

    Küng, Eliane; Coward, William R; Neill, Daniel R; Malak, Hesham A; Mühlemann, Kathrin; Kadioglu, Aras; Hilty, Markus; Hathaway, Lucy J

    2014-01-01

    The polysaccharide capsule and pneumolysin toxin are major virulence factors of the human bacterial pathogen Streptococcus pneumoniae. Colonization of the nasopharynx is asymptomatic but invasion of the lungs can result in invasive pneumonia. Here we show that the capsule suppresses the release of the pro-inflammatory cytokines CXCL8 (IL-8) and IL-6 from the human pharyngeal epithelial cell line Detroit 562. Release of both cytokines was much less from human bronchial epithelial cells (iHBEC) but levels were also affected by capsule. Pneumolysin stimulates CXCL8 release from both cell lines. Suppression of CXCL8 homologue (CXCL2/MIP-2) release by the capsule was also observed in vivo during intranasal colonization of mice but was only discernable in the absence of pneumolysin. When pneumococci were administered intranasally to mice in a model of long term, stable nasopharyngeal carriage, encapsulated S. pneumoniae remained in the nasopharynx whereas the nonencapsulated pneumococci disseminated into the lungs. Pneumococcal capsule plays a role not only in protection from phagocytosis but also in modulation of the pro-inflammatory immune response in the respiratory tract.

  12. Phenotypic Heterogeneity in Expression of the K1 Polysaccharide Capsule of Uropathogenic Escherichia coli and Downregulation of the Capsule Genes during Growth in Urine.

    PubMed

    King, Jane E; Aal Owaif, Hasan A; Jia, Jia; Roberts, Ian S

    2015-07-01

    Uropathogenic Escherichia coli (UPEC) is the major causative agent of uncomplicated urinary tract infections (UTI). The K1 capsule on the surface of UPEC strains is a key virulence factor, and its expression may be important in the onset and progression of UTI. In order to understand capsule expression in more detail, we analyzed its expression in the UPEC strain UTI89 during growth in rich medium (LB medium) and urine and during infection of a bladder epithelial cell line. Comparison of capsule gene transcription using a chromosomal gfp reporter fusion showed a significant reduction in transcription during growth in urine compared to that during growth in LB medium. When examined at the single-cell level, following growth in both media, capsule gene expression appears to be heterogeneous, with two distinct green fluorescent protein (GFP)-expressing populations. Using anti-K1 antibody, we showed that this heterogeneity in gene expression results in two populations of encapsulated and unencapsulated cells. We demonstrated that the capsule hinders attachment to and invasion of epithelial cells and that the unencapsulated cells within the population preferentially adhere to and invade bladder epithelial cells. We found that once internalized, UTI89 starts to produce capsule to aid in its intracellular survival and spread. We propose that this observed phenotypic diversity in capsule expression is a fitness strategy used by the bacterium to deal with the constantly changing environment of the urinary tract.

  13. Phenotypic Heterogeneity in Expression of the K1 Polysaccharide Capsule of Uropathogenic Escherichia coli and Downregulation of the Capsule Genes during Growth in Urine

    PubMed Central

    King, Jane E.; Aal Owaif, Hasan A.; Jia, Jia

    2015-01-01

    Uropathogenic Escherichia coli (UPEC) is the major causative agent of uncomplicated urinary tract infections (UTI). The K1 capsule on the surface of UPEC strains is a key virulence factor, and its expression may be important in the onset and progression of UTI. In order to understand capsule expression in more detail, we analyzed its expression in the UPEC strain UTI89 during growth in rich medium (LB medium) and urine and during infection of a bladder epithelial cell line. Comparison of capsule gene transcription using a chromosomal gfp reporter fusion showed a significant reduction in transcription during growth in urine compared to that during growth in LB medium. When examined at the single-cell level, following growth in both media, capsule gene expression appears to be heterogeneous, with two distinct green fluorescent protein (GFP)-expressing populations. Using anti-K1 antibody, we showed that this heterogeneity in gene expression results in two populations of encapsulated and unencapsulated cells. We demonstrated that the capsule hinders attachment to and invasion of epithelial cells and that the unencapsulated cells within the population preferentially adhere to and invade bladder epithelial cells. We found that once internalized, UTI89 starts to produce capsule to aid in its intracellular survival and spread. We propose that this observed phenotypic diversity in capsule expression is a fitness strategy used by the bacterium to deal with the constantly changing environment of the urinary tract. PMID:25870229

  14. Structural characterization of Streptococcus pneumoniae serotype 9A capsule polysaccharide reveals role of glycosyl 6-O-acetyltransferase wcjE in serotype 9V capsule biosynthesis and immunogenicity.

    PubMed

    Calix, Juan J; Saad, Jamil S; Brady, Allison M; Nahm, Moon H

    2012-04-20

    The putative capsule O-acetyltransferase gene wcjE is highly conserved across various Streptococcus pneumoniae serotypes, but the role of the gene in capsule biosynthesis and bacterial fitness remains largely unclear. Isolates expressing pneumococcal serotype 9A arise from precursors expressing wcjE-associated serotype 9V through loss-of-function mutation to wcjE. To define the biosynthetic role of 9V wcjE, we characterized the structure and serological properties of serotype 9V and 9A capsule polysaccharide (PS). NMR data revealed that both 9V and 9A PS are composed of an identical pentasaccharide repeat unit, as reported previously. However, in sharp contrast to previous studies on 9A PS being devoid of any O-acetylation, we identified O-acetylation of α-glucuronic acid and α-glucose in 9A PS. In addition, 9V PS also contained -CH(2) O-acetylation of β-N-acetylmannosamine, a modification that disappeared following in vitro recombinatorial deletion of wcjE. We also show that serotyping sera and monoclonal antibodies specific for 9V and 9A bound capsule PS in an O-acetate-dependent manner. Furthermore, IgG and to a lesser extent IgM from human donors immunized with serotype 9V PS displayed stronger binding to 9V compared with 9A PS. We conclude that serotype 9V wcjE mediates 6-O-acetylation of β-N-acetylmannosamine. This PS modification can be selectively targeted by antibodies in immunized individuals, identifying a potential selective advantage for wcjE inactivation and serotype 9A emergence.

  15. Structure elucidation of the capsular polysaccharide of Acinetobacter baumannii AB5075 having the KL25 capsule biosynthesis locus.

    PubMed

    Senchenkova, Sof'ya N; Shashkov, Alexander S; Popova, Anastasiya V; Shneider, Mikhail M; Arbatsky, Nikolay P; Miroshnikov, Konstantin A; Volozhantsev, Nikolay V; Knirel, Yuriy A

    2015-05-18

    Capsular polysaccharide was isolated by the phenol-water extraction of Acinetobacter baumannii AB5075 and studied by 1D and 2D (1)H and (13)C NMR spectroscopy. The following structure of the linear trisaccharide repeating unit was established: → 3)-β-D-ManpNAcA-(1 → 4)-β-D-ManpNAcA-(1 → 3)-α-D-QuipNAc4NR-(1 → where R indicates (S)-3-hydroxybutanoyl or acetyl in the ratio ∼ 2.5:1. The genes in the polysaccharide biosynthesis locus designated KL25 are appropriate to the established CPS structure.

  16. Structure of the capsular polysaccharide of Acinetobacter baumannii 1053 having the KL91 capsule biosynthesis gene locus.

    PubMed

    Shashkov, Alexander S; Shneider, Mikhail M; Senchenkova, Sof'ya N; Popova, Anastasiya V; Nikitina, Anastasia S; Babenko, Vladislav V; Kostryukova, Elena S; Miroshnikov, Konstantin A; Volozhantsev, Nikolay V; Knirel, Yuriy A

    2015-03-01

    Acinetobacter baumannii 1053 is the type strain for the maintenance of specific bacteriophage AP22, which infects a fairly broad range of A. baumannii strains circulating in Russian clinics and hospitals. A capsular polysaccharide (CPS) was isolated from cells of strain 1053 and studied by sugar analysis along with 1D and 2D (1)H and (13)C NMR spectroscopy. The following structure of the linear trisaccharide repeating unit was established: -->4)-β-D-ManpNAcA-(1-->4)-β-D-ManpNAcA-(1-->3)-α-D-FucpNAc-(1--> where ManNAcA and FucNAc indicate 2-acetamido-2-deoxymannuronic acid and 2-acetamido-2,6-dideoxygalactose, respectively. A polysaccharide having the same repeating unit but a shorter chain was isolated by the phenol-water extraction of bacterial cells. Sequencing of the CPS biosynthesis gene locus showed that A. baumannii 1053 belongs to a new group designated KL91. The gene functions assigned putatively by a comparison with available databases were in agreement with the CPS structure established.

  17. Distinct Mechanisms Underlie Boosted Polysaccharide-Specific IgG Responses Following Secondary Challenge with Intact Gram-Negative versus Gram-Positive Extracellular Bacteria.

    PubMed

    Kar, Swagata; Arjunaraja, Swadhinya; Akkoyunlu, Mustafa; Pier, Gerald B; Snapper, Clifford M

    2016-06-01

    Priming of mice with intact, heat-killed cells of Gram-negative Neisseria meningitidis, capsular serogroup C (MenC) or Gram-positive group B Streptococcus, capsular type III (GBS-III) bacteria resulted in augmented serum polysaccharide (PS)-specific IgG titers following booster immunization. Induction of memory required CD4(+) T cells during primary immunization. We determined whether PS-specific memory for IgG production was contained within the B cell and/or T cell populations, and whether augmented IgG responses following booster immunization were also dependent on CD4(+) T cells. Adoptive transfer of purified B cells from MenC- or GBS-III-primed, but not naive mice resulted in augmented PS-specific IgG responses following booster immunization. Similar responses were observed when cotransferred CD4(+) T cells were from primed or naive mice. Similarly, primary immunization with unencapsulated MenC or GBS-III, to potentially prime CD4(+) T cells, failed to enhance PS-specific IgG responses following booster immunization with their encapsulated isogenic partners. Furthermore, in contrast to GBS-III, depletion of CD4(+) T cells during secondary immunization with MenC or another Gram-negative bacteria, Acinetobacter baumannii, did not inhibit augmented PS-specific IgG booster responses of mice primed with heat-killed cells. Also, in contrast with GBS-III, booster immunization of MenC-primed mice with isolated MenC-PS, a TI Ag, or a conjugate of MenC-PS and tetanus toxoid elicited an augmented PS-specific IgG response similar to booster immunization with intact MenC. These data demonstrate that memory for augmented PS-specific IgG booster responses to Gram-negative and Gram-positive bacteria is contained solely within the B cell compartment, with a differential requirement for CD4(+) T cells for augmented IgG responses following booster immunization. PMID:27183619

  18. Distinct Mechanisms Underlie Boosted Polysaccharide-Specific IgG Responses Following Secondary Challenge with Intact Gram-Negative versus Gram-Positive Extracellular Bacteria.

    PubMed

    Kar, Swagata; Arjunaraja, Swadhinya; Akkoyunlu, Mustafa; Pier, Gerald B; Snapper, Clifford M

    2016-06-01

    Priming of mice with intact, heat-killed cells of Gram-negative Neisseria meningitidis, capsular serogroup C (MenC) or Gram-positive group B Streptococcus, capsular type III (GBS-III) bacteria resulted in augmented serum polysaccharide (PS)-specific IgG titers following booster immunization. Induction of memory required CD4(+) T cells during primary immunization. We determined whether PS-specific memory for IgG production was contained within the B cell and/or T cell populations, and whether augmented IgG responses following booster immunization were also dependent on CD4(+) T cells. Adoptive transfer of purified B cells from MenC- or GBS-III-primed, but not naive mice resulted in augmented PS-specific IgG responses following booster immunization. Similar responses were observed when cotransferred CD4(+) T cells were from primed or naive mice. Similarly, primary immunization with unencapsulated MenC or GBS-III, to potentially prime CD4(+) T cells, failed to enhance PS-specific IgG responses following booster immunization with their encapsulated isogenic partners. Furthermore, in contrast to GBS-III, depletion of CD4(+) T cells during secondary immunization with MenC or another Gram-negative bacteria, Acinetobacter baumannii, did not inhibit augmented PS-specific IgG booster responses of mice primed with heat-killed cells. Also, in contrast with GBS-III, booster immunization of MenC-primed mice with isolated MenC-PS, a TI Ag, or a conjugate of MenC-PS and tetanus toxoid elicited an augmented PS-specific IgG response similar to booster immunization with intact MenC. These data demonstrate that memory for augmented PS-specific IgG booster responses to Gram-negative and Gram-positive bacteria is contained solely within the B cell compartment, with a differential requirement for CD4(+) T cells for augmented IgG responses following booster immunization.

  19. H-NS Nucleoid Protein Controls Virulence Features of Klebsiella pneumoniae by Regulating the Expression of Type 3 Pili and the Capsule Polysaccharide

    PubMed Central

    Ares, Miguel A.; Fernández-Vázquez, José L.; Rosales-Reyes, Roberto; Jarillo-Quijada, Ma. Dolores; von Bargen, Kristine; Torres, Javier; González-y-Merchand, Jorge A.; Alcántar-Curiel, María D.; De la Cruz, Miguel A.

    2016-01-01

    Klebsiella pneumoniae is an opportunistic pathogen causing nosocomial infections. Main virulence determinants of K. pneumoniae are pili, capsular polysaccharide, lipopolysaccharide, and siderophores. The histone-like nucleoid-structuring protein (H-NS) is a pleiotropic regulator found in several gram-negative pathogens. It has functions both as an architectural component of the nucleoid and as a global regulator of gene expression. We generated a Δhns mutant and evaluated the role of the H-NS nucleoid protein on the virulence features of K. pneumoniae. A Δhns mutant down-regulated the mrkA pilin gene and biofilm formation was affected. In contrast, capsule expression was derepressed in the absence of H-NS conferring a hypermucoviscous phenotype. Moreover, H-NS deficiency affected the K. pneumoniae adherence to epithelial cells such as A549 and HeLa cells. In infection experiments using RAW264.7 and THP-1 differentiated macrophages, the Δhns mutant was less phagocytized than the wild-type strain. This phenotype was likely due to the low adherence to these phagocytic cells. Taken together, our data indicate that H-NS nucleoid protein is a crucial regulator of both T3P and CPS of K. pneumoniae. PMID:26904512

  20. Functional and structural characterization of polysaccharide co-polymerase proteins required for polymer export in ATP-binding cassette transporter-dependent capsule biosynthesis pathways.

    PubMed

    Larue, Kane; Ford, Robert C; Willis, Lisa M; Whitfield, Chris

    2011-05-13

    Neisseria meningitidis serogroup B and Escherichia coli K1 bacteria produce a capsular polysaccharide (CPS) that is composed of α2,8-linked polysialic acid (PSA). Biosynthesis of PSA in these bacteria occurs via an ABC (ATP-binding cassette) transporter-dependent pathway. In N. meningitidis, export of PSA to the surface of the bacterium requires two proteins that form an ABC transporter (CtrC and CtrD) and two additional proteins, CtrA and CtrB, that are proposed to form a cell envelope-spanning export complex. CtrA is a member of the outer membrane polysaccharide export (OPX) family of proteins, which are proposed to form a pore to mediate export of CPSs across the outer membrane. CtrB is an inner membrane protein belonging to the polysaccharide co-polymerase (PCP) family. PCP proteins involved in other bacterial polysaccharide assembly systems form structures that extend into the periplasm from the inner membrane. There is currently no structural information available for PCP or OPX proteins involved in an ABC transporter-dependent CPS biosynthesis pathway to support their proposed roles in polysaccharide export. Here, we report cryo-EM images of purified CtrB reconstituted into lipid bilayers. These images contained molecular top and side views of CtrB and showed that it formed a conical oligomer that extended ∼125 Å from the membrane. This structure is consistent with CtrB functioning as a component of an envelope-spanning complex. Cross-complementation of CtrA and CtrB in E. coli mutants with defects in genes encoding the corresponding PCP and OPX proteins show that PCP-OPX pairs require interactions with their cognate partners to export polysaccharide. These experiments add further support for the model of an ABC transporter-PCP-OPX multiprotein complex that functions to export CPS across the cell envelope.

  1. Biochemical And Genetic Modification Of Polysaccharides

    NASA Technical Reports Server (NTRS)

    Kern, Roger G.; Petersen, Gene R.; Richards, Gil F.

    1993-01-01

    Bacteriophages producing endopolysaccharase-type enzymes used to produce, isolate, and purify high yields of modified polysaccharides from polysaccharides produced by, and incorporated into capsules of, certain bacteria. Bacteriophages used in conversion of native polysaccharide materials into polymers of nearly uniform high molecular weight or, alternatively, into highly pure oligosaccharides. Also used in genetic selection of families of polysaccharides structurally related to native polysaccharide materials, but having altered properties. Resulting new polysaccharides and oligosaccharides prove useful in variety of products, including pharmaceutical chemicals, coating materials, biologically active carbohydrates, and drag-reducing additives for fluids.

  2. Fis is essential for capsule production in Pasteurella multocida and regulates expression of other important virulence factors.

    PubMed

    Steen, Jason A; Steen, Jennifer A; Harrison, Paul; Seemann, Torsten; Wilkie, Ian; Harper, Marina; Adler, Ben; Boyce, John D

    2010-02-05

    P. multocida is the causative agent of a wide range of diseases of animals, including fowl cholera in poultry and wild birds. Fowl cholera isolates of P. multocida generally express a capsular polysaccharide composed of hyaluronic acid. There have been reports of spontaneous capsule loss in P. multocida, but the mechanism by which this occurs has not been determined. In this study, we identified three independent strains that had spontaneously lost the ability to produce capsular polysaccharide. Quantitative RT-PCR showed that these strains had significantly reduced transcription of the capsule biosynthetic genes, but DNA sequence analysis identified no mutations within the capsule biosynthetic locus. However, whole-genome sequencing of paired capsulated and acapsular strains identified a single point mutation within the fis gene in the acapsular strain. Sequencing of fis from two independently derived spontaneous acapsular strains showed that each contained a mutation within fis. Complementation of these strains with an intact copy of fis, predicted to encode a transcriptional regulator, returned capsule expression to all strains. Therefore, expression of a functional Fis protein is essential for capsule expression in P. multocida. DNA microarray analysis of one of the spontaneous fis mutants identified approximately 30 genes as down-regulated in the mutant, including pfhB_2, which encodes a filamentous hemagglutinin, a known P. multocida virulence factor, and plpE, which encodes the cross protective surface antigen PlpE. Therefore these experiments define for the first time a mechanism for spontaneous capsule loss in P. multocida and identify Fis as a critical regulator of capsule expression. Furthermore, Fis is involved in the regulation of a range of other P. multocida genes including important virulence factors.

  3. Structures of three different neutral polysaccharides of Acinetobacter baumannii, NIPH190, NIPH201, and NIPH615, assigned to K30, K45, and K48 capsule types, respectively, based on capsule biosynthesis gene clusters.

    PubMed

    Shashkov, Alexander S; Kenyon, Johanna J; Arbatsky, Nikolay P; Shneider, Mikhail M; Popova, Anastasiya V; Miroshnikov, Konstantin A; Volozhantsev, Nikolay V; Knirel, Yuriy A

    2015-11-19

    Neutral capsular polysaccharides (CPSs) were isolated from Acinetobacter baumannii NIPH190, NIPH201, and NIPH615. The CPSs were found to contain common monosaccharides only and to be branched with a side-chain 1→3-linked β-d-glucopyranose residue. Structures of the oligosaccharide repeat units (K units) of the CPSs were elucidated by 1D and 2D (1)H and (13)C NMR spectroscopy. Novel CPS biosynthesis gene clusters, designated KL30, KL45, and KL48, were found at the K locus in the genome sequences of NIPH190, NIPH201, and NIPH615, respectively. The genetic content of each gene cluster correlated with the structure of the CPS unit established, and therefore, the capsular types of the strains studied were designated as K30, K45, and K48, respectively. The initiating sugar of each K unit was predicted, and glycosyltransferases encoded by each gene cluster were assigned to the formation of the linkages between sugars in the corresponding K unit.

  4. The effect of glicerol and sorbitol plasticizers toward disintegration time of phyto-capsules

    NASA Astrophysics Data System (ADS)

    Pudjiastuti, Pratiwi; Hendradi, Esti; Wafiroh, Siti; Harsini, Muji; Darmokoesoemo, Handoko

    2016-03-01

    The aim of research is determining the effect of glycerol and sorbitol toward the disintegration time of phyto-capsules, originated capsules from plant polysaccharides. Phyto-capsules were made from polysaccharides and 0.5% (v/v) of glycerol and sorbitol of each. The seven capsules of each were determined the disintegration time using Erweka disintegrator. The mean of disintegration time of phyto-capsules without plasticizers, with glycerol and sorbitol were 25'30"; 45'15" and 35'30" respectively. The color and colorless gelatin capsules showed the mean of disintegration time 7'30" and 2'35" respectively.

  5. Regulation of capsule in Neisseria meningitidis.

    PubMed

    Tzeng, Yih-Ling; Thomas, Jennifer; Stephens, David S

    2016-09-01

    Neisseria meningitidis, a devastating pathogen exclusive to humans, expresses capsular polysaccharides that are the major meningococcal virulence determinants and the basis for successful meningococcal vaccines. With rare exceptions, the expression of capsule (serogroups A, B, C, W, X, Y) is required for systemic invasive meningococcal disease. Changes in capsule expression or structure (e.g. hypo- or hyper-encapsulation, capsule "switching", acetylation) can influence immunologic diagnostic assays or lead to immune escape. The loss or down-regulation of capsule is also critical in meningococcal biology facilitating meningococcal attachment, microcolony formation and the carriage state at human mucosal surfaces. Encapsulated meningococci contain a cps locus with promoters located in an intergenic region between the biosynthesis and the conserved capsule transport operons. The cps intergenic region is transcriptionally regulated (and thus the amount of capsule expressed) by IS element insertion, by a two-component system, MisR/MisS and through sequence changes that result in post-transcriptional RNA thermoregulation. Reversible on-off phase variation of capsule expression is controlled by slipped strand mispairing of homo-polymeric tracts and by precise insertion and excision of IS elements (e.g. IS1301) in the biosynthesis operon. Capsule structure can be altered by phase-variable expression of capsular polymer modification enzymes or "switched" through transformation and homologous recombination of different polymerases. Understanding the complex regulation of meningococcal capsule has important implications for meningococcal biology, pathogenesis, diagnostics, current and future vaccine development and vaccine strategies.

  6. Regulation of capsule in Neisseria meningitidis.

    PubMed

    Tzeng, Yih-Ling; Thomas, Jennifer; Stephens, David S

    2016-09-01

    Neisseria meningitidis, a devastating pathogen exclusive to humans, expresses capsular polysaccharides that are the major meningococcal virulence determinants and the basis for successful meningococcal vaccines. With rare exceptions, the expression of capsule (serogroups A, B, C, W, X, Y) is required for systemic invasive meningococcal disease. Changes in capsule expression or structure (e.g. hypo- or hyper-encapsulation, capsule "switching", acetylation) can influence immunologic diagnostic assays or lead to immune escape. The loss or down-regulation of capsule is also critical in meningococcal biology facilitating meningococcal attachment, microcolony formation and the carriage state at human mucosal surfaces. Encapsulated meningococci contain a cps locus with promoters located in an intergenic region between the biosynthesis and the conserved capsule transport operons. The cps intergenic region is transcriptionally regulated (and thus the amount of capsule expressed) by IS element insertion, by a two-component system, MisR/MisS and through sequence changes that result in post-transcriptional RNA thermoregulation. Reversible on-off phase variation of capsule expression is controlled by slipped strand mispairing of homo-polymeric tracts and by precise insertion and excision of IS elements (e.g. IS1301) in the biosynthesis operon. Capsule structure can be altered by phase-variable expression of capsular polymer modification enzymes or "switched" through transformation and homologous recombination of different polymerases. Understanding the complex regulation of meningococcal capsule has important implications for meningococcal biology, pathogenesis, diagnostics, current and future vaccine development and vaccine strategies. PMID:26089023

  7. Description and nomenclature of Neisseria meningitidis capsule locus.

    PubMed

    Harrison, Odile B; Claus, Heike; Jiang, Ying; Bennett, Julia S; Bratcher, Holly B; Jolley, Keith A; Corton, Craig; Care, Rory; Poolman, Jan T; Zollinger, Wendell D; Frasch, Carl E; Stephens, David S; Feavers, Ian; Frosch, Matthias; Parkhill, Julian; Vogel, Ulrich; Quail, Michael A; Bentley, Stephen D; Maiden, Martin C J

    2013-04-01

    Pathogenic Neisseria meningitidis isolates contain a polysaccharide capsule that is the main virulence determinant for this bacterium. Thirteen capsular polysaccharides have been described, and nuclear magnetic resonance spectroscopy has enabled determination of the structure of capsular polysaccharides responsible for serogroup specificity. Molecular mechanisms involved in N. meningitidis capsule biosynthesis have also been identified, and genes involved in this process and in cell surface translocation are clustered at a single chromosomal locus termed cps. The use of multiple names for some of the genes involved in capsule synthesis, combined with the need for rapid diagnosis of serogroups commonly associated with invasive meningococcal disease, prompted a requirement for a consistent approach to the nomenclature of capsule genes. In this report, a comprehensive description of all N. meningitidis serogroups is provided, along with a proposed nomenclature, which was presented at the 2012 XVIIIth International Pathogenic Neisseria Conference.

  8. The capsule of the fungal pathogen Cryptococcus neoformans.

    PubMed

    Zaragoza, Oscar; Rodrigues, Marcio L; De Jesus, Magdia; Frases, Susana; Dadachova, Ekaterina; Casadevall, Arturo

    2009-01-01

    The capsule of the fungal pathogen Cryptococcus neoformans has been studied extensively in recent decades and a large body of information is now available to the scientific community. Well-known aspects of the capsule include its structure, antigenic properties and its function as a virulence factor. The capsule is composed primarily of two polysaccharides, glucuronoxylomannan (GXM) and galactoxylomannan (GalXM), in addition to a smaller proportion of mannoproteins (MPs). Most of the studies on the composition of the capsule have focused on GXM, which comprises more than 90% of the capsule's polysaccharide mass. It is GalXM, however, that is of particular scientific interest because of its immunological properties. The molecular structure of these polysaccharides is very complex and has not yet been fully elucidated. Both GXM and GalXM are high molecular mass polymers with the mass of GXM equaling roughly 10 times that of GalXM. Recent findings suggest, however, that the actual molecular weight might be different to what it has traditionally been thought to be. In addition to their structural roles in the polysaccharide capsule, these molecules have been associated with many deleterious effects on the immune response. Capsular components are therefore considered key virulence determinants in C. neoformans, which has motivated their use in vaccines and made them targets for monoclonal antibody treatments. In this review, we will provide an update on the current knowledge of the C. neoformans capsule, covering aspects related to its structure, synthesis and particularly, its role as a virulence factor.

  9. The capsule of the fungal pathogen Cryptococcus neoformans

    PubMed Central

    Zaragoza, Oscar; Rodrigues, Marcio L.; De Jesus, Magdia; Frases, Susana; Dadachova, Ekaterina; Casadevall, Arturo

    2009-01-01

    The capsule of the fungal pathogen Cryptococcus neoformans has been studied extensively in recent decades, and a large body of information is now available to the scientific community. Well-known aspects of the capsule include its structure, antigenic properties and its function as a virulence factor. The capsule is composed primarily of two polysaccharides, glucuronoxylomannan (GXM) and galactoxylomannan (GalXM), in addition to a smaller proportion of mannoproteins (MP). Most of the studies on the composition of the capsule have focused on GXM, which comprises more than 90% of the capsule's polysaccharide mass. It is GalXM, however, that is of particular scientific interest because of its immunological properties. The molecular structure of these polysaccharides is very complex and has not yet been fully elucidated. Both GXM and GalXM are high molecular mass polymers with the mass of GXM equaling roughly 10 times that of GalXM. Recent findings suggest, however, that the actual Mw might be different to what it has traditionally been thought to be. In addition to their structural roles in the polysaccharide capsule, these molecules have been associated with many deleterious effects on the immune response. Capsular components are therefore considered key virulence determinants in Cryptococcus neoformans, which has motivated their use in vaccines and made them targets for monoclonal antibody treatments. In this review we will provide an update on the current knowledge of the C. neoformans capsule, covering aspects related to its structure, synthesis, and particularly, its role as a virulence factor. PMID:19426855

  10. Capsule type of Streptococcus pneumoniae determines growth phenotype.

    PubMed

    Hathaway, Lucy J; Brugger, Silvio D; Morand, Brigitte; Bangert, Mathieu; Rotzetter, Jeannine U; Hauser, Christoph; Graber, Werner A; Gore, Suzanna; Kadioglu, Aras; Mühlemann, Kathrin

    2012-01-01

    The polysaccharide capsule of Streptococcus pneumoniae defines over ninety serotypes, which differ in their carriage prevalence and invasiveness for poorly understood reasons. Recently, an inverse correlation between carriage prevalence and oligosaccharide structure of a given capsule has been described. Our previous work suggested a link between serotype and growth in vitro. Here we investigate whether capsule production interferes with growth in vitro and whether this predicts carriage prevalence in vivo. Eighty-one capsule switch mutants were constructed representing nine different serotypes, five of low (4, 7F, 14, 15, 18C) and four of high carriage prevalence (6B, 9V, 19F, 23F). Growth (length of lag phase, maximum optical density) of wildtype strains, nontypeable mutants and capsule switch mutants was studied in nutrient-restricted Lacks medium (MLM) and in rich undefined brain heart infusion broth supplemented with 5% foetal calf serum (BHI+FCS). In MLM growth phenotype depended on, and was transferred with, capsule operon type. Colonization efficiency of mouse nasopharynx also depended on, and was transferred with, capsule operon type. Capsule production interfered with growth, which correlated inversely with serotype-specific carriage prevalence. Serotypes with better growth and higher carriage prevalence produced thicker capsules (by electron microscopy, FITC-dextran exclusion assays and HPLC) than serotypes with delayed growth and low carriage prevalence. However, expression of cpsA, the first capsule gene, (by quantitative RT-PCR) correlated inversely with capsule thickness. Energy spent for capsule production (incorporation of H3-glucose) relative to amount of capsule produced was higher for serotypes with low carriage prevalence. Experiments in BHI+FCS showed overall better bacterial growth and more capsule production than growth in MLM and differences between serotypes were no longer apparent. Production of polysaccharide capsule in S. pneumoniae

  11. Further electron microscopic studies on the expression of Escherichia coli group II capsules.

    PubMed Central

    Kröncke, K D; Golecki, J R; Jann, K

    1990-01-01

    The de novo expression of Escherichia coli K1, K5, and K12 capsules was analyzed with immunoelectron microscopy in temperature upshift experiments, with upshift from 18 degrees C (capsule restrictive) to 37 degrees C (capsule permissive). Newly produced capsular polysaccharides appeared at the cell surface atop membrane adhesion sites (Bayer's junctions). After plasmolysis of the bacteria at an early expression stage, the capsular polysaccharides were labeled at discrete sites in the periplasm by the immunogold technique. After temperature upshift in the presence of carbonyl cyanide m-chlorophenylhydrazone (CCCP) or chloramphenicol, the polysaccharides were labeled in the cytoplasm. Images PMID:2188961

  12. Cryptococcus neoformans capsular polysaccharides form branched and complex filamentous networks viewed by high-resolution microscopy.

    PubMed

    Araújo, Glauber R de S; Fontes, Giselle N; Leão, Daniela; Rocha, Gustavo Miranda; Pontes, Bruno; Sant'Anna, Celso; de Souza, Wanderley; Frases, Susana

    2016-01-01

    Cryptococcus neoformans is a fungal pathogen that causes life-threatening infections in immunocompromised individuals. Its main virulence factor is an extracellular polysaccharide capsule whose structure, assembly and dynamics remain poorly understood. In this study, we apply improved protocols for sample preparation and recently-developed scanning microscopy techniques to visualize the ultrastructure of the C. neoformans capsule at high-resolution (up to 1 nm) and improved structural preservation. Although most capsule structures in nature consist of linear polymers, we show here that the C. neoformans capsule is a 'microgel-like' structure composed of branched polysaccharides. Moreover, we imaged the capsule-to-cell wall link, which is formed by thin fibers that branch out of thicker capsule filaments, and have one end firmly embedded in the cell wall structure. Together, our findings provide compelling ultrastructural evidence for a branched and complex capsule conformation, which may have important implications for the biological activity of the capsule as a virulence factor.

  13. Temperature Capsule

    NASA Technical Reports Server (NTRS)

    1992-01-01

    An ingestible mini-thermometer capable of measuring and relaying internal body temperatures is marketed by Human Technologies, Inc. The CorTemp system, developed by Goddard Space Flight Center and Applied Physics Lab, incorporates space technologies, among them telemetry and microminiaturized circuit, sensor and battery technologies. The capsule is ingested and continually monitors temperature with a vibrating quartz crystal sensor, which telemeters signals to a recorder, where data is displayed and stored. The system is very accurate, and because it does not require wires, allows patients to be monitored in everyday situations. The industrial variant (CSC-100) has wide utility in commercial applications.

  14. Spacecraft -- Capsule Separation (Animation)

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Click on the image for Spacecraft -- Capsule Separation animation

    This animation shows the return capsule separating from the Stardust spacecraft.

  15. Antibiofilm activity of Actinobacillus pleuropneumoniae serotype 5 capsular polysaccharide.

    PubMed

    Karwacki, Michael T; Kadouri, Daniel E; Bendaoud, Meriem; Izano, Era A; Sampathkumar, Vandana; Inzana, Thomas J; Kaplan, Jeffrey B

    2013-01-01

    Cell-free extracts isolated from colony biofilms of Actinobacillus pleuropneumoniae serotype 5 were found to inhibit biofilm formation by Staphylococcus aureus, S. epidermidis and Aggregatibacter actinomycetemcomitans, but not by A. pleuropneumoniae serotype 5 itself, in a 96-well microtiter plate assay. Physical and chemical analyses indicated that the antibiofilm activity in the extract was due to high-molecular-weight polysaccharide. Extracts isolated from a mutant strain deficient in the production of serotype 5 capsular polysaccharide did not exhibit antibiofilm activity. A plasmid harboring the serotype 5 capsule genes restored the antibiofilm activity in the mutant extract. Purified serotype 5 capsular polysaccharide also exhibited antibiofilm activity against S. aureus. A. pleuropneumoniae wild-type extracts did not inhibit S. aureus growth, but did inhibit S. aureus intercellular adhesion and binding of S. aureus cells to stainless steel surfaces. Furthermore, polystyrene surfaces coated with A. pleuropneumoniae wild-type extracts, but not with capsule-mutant extracts, resisted S. aureus biofilm formation. Our findings suggest that the A. pleuropneumoniae serotype 5 capsule inhibits cell-to-cell and cell-to-surface interactions of other bacteria. A. pleuropneumoniae serotype 5 capsular polysaccharide is one of a growing number of bacterial polysaccharides that exhibit broad-spectrum, nonbiocidal antibiofilm activity. Future studies on these antibiofilm polysaccharides may uncover novel functions for bacterial polysaccharides in nature, and may lead to the development of new classes of antibiofilm agents for industrial and clinical applications. PMID:23691104

  16. Antibiofilm Activity of Actinobacillus pleuropneumoniae Serotype 5 Capsular Polysaccharide

    PubMed Central

    Karwacki, Michael T.; Kadouri, Daniel E.; Bendaoud, Meriem; Izano, Era A.; Sampathkumar, Vandana; Inzana, Thomas J.; Kaplan, Jeffrey B.

    2013-01-01

    Cell-free extracts isolated from colony biofilms of Actinobacillus pleuropneumoniae serotype 5 were found to inhibit biofilm formation by Staphylococcus aureus, S. epidermidis and Aggregatibacter actinomycetemcomitans, but not by A. pleuropneumoniae serotype 5 itself, in a 96-well microtiter plate assay. Physical and chemical analyses indicated that the antibiofilm activity in the extract was due to high-molecular-weight polysaccharide. Extracts isolated from a mutant strain deficient in the production of serotype 5 capsular polysaccharide did not exhibit antibiofilm activity. A plasmid harboring the serotype 5 capsule genes restored the antibiofilm activity in the mutant extract. Purified serotype 5 capsular polysaccharide also exhibited antibiofilm activity against S. aureus. A. pleuropneumoniae wild-type extracts did not inhibit S. aureus growth, but did inhibit S. aureus intercellular adhesion and binding of S. aureus cells to stainless steel surfaces. Furthermore, polystyrene surfaces coated with A. pleuropneumoniae wild-type extracts, but not with capsule-mutant extracts, resisted S. aureus biofilm formation. Our findings suggest that the A. pleuropneumoniae serotype 5 capsule inhibits cell-to-cell and cell-to-surface interactions of other bacteria. A. pleuropneumoniae serotype 5 capsular polysaccharide is one of a growing number of bacterial polysaccharides that exhibit broad-spectrum, nonbiocidal antibiofilm activity. Future studies on these antibiofilm polysaccharides may uncover novel functions for bacterial polysaccharides in nature, and may lead to the development of new classes of antibiofilm agents for industrial and clinical applications. PMID:23691104

  17. BASICS OF COMPOUNDING: Capsules.

    PubMed

    Allen, Loyd V

    2016-01-01

    Capsules have been used for administering medications to patients more than a century and have an important role in drug delivery. When a primary care provider prescribes a tablet, the choice is usually, but not always, limited to commercially available products. A capsule, however, can be prepared extemporaneously, which provides dosing flexibility for the primary care provider and the pharmacist. This article discusses the definitions/types of capsules, their applications, composition, preparation, capsule sizes, the encapsulation process, capsule cleaning, physiochemical considerations, quality control in the preparation of capsules, packaging/storage, stability, and patient counseling to determine the proper capsule size. Also, provided are sample formulations.

  18. Polysaccharide Degradation

    NASA Astrophysics Data System (ADS)

    Stone, Bruce A.; Svensson, Birte; Collins, Michelle E.; Rastall, Robert A.

    An overview of current and potential enzymes used to degrade polysaccharides is presented. Such depolymerases are comprised of glycoside hydrolases, glycosyl transferases, phosphorylases and lyases, and their classification, active sites and action patterns are discussed. Additionally, the mechanisms that these enzymes use to cleave glycosidic linkages is reviewed as are inhibitors of depolymerase activity; reagents which react with amino acid residues, glycoside derivatives, transition state inhibitors and proteinaceous inhibitors. The characterization of various enzymes of microbial, animal or plant origin has led to their widespread use in the production of important oligosaccharides which can be incorporated into food stuffs. Sources of polysaccharides of particular interest in this chapter are those from plants and include inulin, dextran, xylan and pectin, as their hydrolysis products are purported to be functional foods in the context of gastrointestinal health. An alternative use of degraded polysaccharides is in the treatment of disease. The possibility exists to treat bacterial exopolysaccharide with lyases from bacteriophage to produce oligosaccharides exhibiting bioactive sequences. Although this area is currently in its infancy the knowledge is available to investigate further.

  19. Recombinant expression of Streptococcus pneumoniae capsular polysaccharides in Escherichia coli

    PubMed Central

    Kay, Emily J.; Yates, Laura E.; Terra, Vanessa S.; Cuccui, Jon; Wren, Brendan W.

    2016-01-01

    Currently, Streptococcus pneumoniae is responsible for over 14 million cases of pneumonia worldwide annually, and over 1 million deaths, the majority of them children. The major determinant for pathogenesis is a polysaccharide capsule that is variable and is used to distinguish strains based on their serotype. The capsule forms the basis of the pneumococcal polysaccharide vaccine (PPV23) that contains purified capsular polysaccharide from 23 serotypes, and the pneumococcal conjugate vaccine (PCV13), containing 13 common serotypes conjugated to CRM197 (mutant diphtheria toxin). Purified capsule from S. pneumoniae is required for pneumococcal conjugate vaccine production, and costs can be prohibitively high, limiting accessibility of the vaccine in low-income countries. In this study, we demonstrate the recombinant expression of the capsule-encoding locus from four different serotypes of S. pneumoniae within Escherichia coli. Furthermore, we attempt to identify the minimum set of genes necessary to reliably and efficiently express these capsules heterologously. These E. coli strains could be used to produce a supply of S. pneumoniae serotype-specific capsules without the need to culture pathogenic bacteria. Additionally, these strains could be applied to synthetic glycobiological applications: recombinant vaccine production using E. coli outer membrane vesicles or coupling to proteins using protein glycan coupling technology. PMID:27110302

  20. Role of Vibrio cholerae O139 surface polysaccharides in intestinal colonization.

    PubMed

    Nesper, Jutta; Schild, Stefan; Lauriano, Crystal M; Kraiss, Anita; Klose, Karl E; Reidl, Joachim

    2002-11-01

    Since the first occurrence of O139 Vibrio cholerae as a cause of cholera epidemics, this serogroup has been investigated intensively, and it has been found that its pathogenicity is comparable to that of O1 El Tor strains. O139 isolates express a thin capsule, composed of a polymer of repeating units structurally identical to the lipopolysaccharide (LPS) O side chain. In this study, we investigated the role of LPS O side chain and capsular polysaccharide (CPS) in intestinal colonization by with genetically engineered mutants. We constructed CPS-negative, CPS/LPS O side chain-negative, and CPS-positive/LPS O side chain-negative mutants. Furthermore, we constructed two mutants with defects in LPS core oligosaccharide (OS) assembly. Loss of LPS O side chain or CPS resulted in a approximately 30-fold reduction in colonization of the infant mouse small intestine, indicating that the presence of both LPS O side chain and CPS is important during the colonization process. The strain lacking both CPS and LPS O side chain and a CPS-positive, LPS O side chain-negative core OS mutant were both essentially unable to colonize. To characterize the role of surface polysaccharides in survival in the host intestine, resistance to several antimicrobial substances was investigated in vitro. These investigations revealed that the presence of CPS protects the cell against attack of the complement system and that an intact core OS is necessary for survival in the presence of bile. PMID:12379674

  1. Sweat collection capsule

    NASA Technical Reports Server (NTRS)

    Delaplaine, R. W.; Greenleaf, J. E.

    1979-01-01

    Capsule, with filter paper insert, is used to collect sweat for rate monitoring, chromatographic analysis, or active sweat gland location within specified area. Construction of capsule allows change of inserts while device remains strapped in place.

  2. The Elastic Properties of the Cryptococcus neoformans Capsule

    PubMed Central

    Frases, Susana; Pontes, Bruno; Nimrichter, Leonardo; Rodrigues, Marcio L.; Viana, Nathan B.; Casadevall, Arturo

    2009-01-01

    Abstract Microbial capsules are important for virulence, but their architecture and physical properties are poorly understood. The human pathogenic fungus Cryptococcus neoformans has a large polysaccharide capsule that is necessary for virulence and is the target of protective antibody responses. To study the C. neoformans capsule we developed what we believe is a new approach whereby we probed the capsular elastic properties by applying forces using polystyrene beads manipulated with optical tweezers. This method allowed us to determine the Young's modulus for the capsule in various conditions that affect capsule growth. The results indicate that the Young's modulus of the capsule decreases with its size and increases with the Ca2+ concentration in solution. Also, capsular polysaccharide manifests an unexpected affinity for polystyrene beads, a property that may function in attachment to host cells and environmental structures. Bead probing with optical tweezers provides a new, nondestructive method that may have wide applicability for studying the effects of growth conditions, immune components, and drugs on capsular properties. PMID:19686640

  3. The elastic properties of the Cryptococcus neoformans capsule.

    PubMed

    Frases, Susana; Pontes, Bruno; Nimrichter, Leonardo; Rodrigues, Marcio L; Viana, Nathan B; Casadevall, Arturo

    2009-08-19

    Microbial capsules are important for virulence, but their architecture and physical properties are poorly understood. The human pathogenic fungus Cryptococcus neoformans has a large polysaccharide capsule that is necessary for virulence and is the target of protective antibody responses. To study the C. neoformans capsule we developed what we believe is a new approach whereby we probed the capsular elastic properties by applying forces using polystyrene beads manipulated with optical tweezers. This method allowed us to determine the Young's modulus for the capsule in various conditions that affect capsule growth. The results indicate that the Young's modulus of the capsule decreases with its size and increases with the Ca(2+) concentration in solution. Also, capsular polysaccharide manifests an unexpected affinity for polystyrene beads, a property that may function in attachment to host cells and environmental structures. Bead probing with optical tweezers provides a new, nondestructive method that may have wide applicability for studying the effects of growth conditions, immune components, and drugs on capsular properties.

  4. Streptococcus pneumoniae capsule determines disease severity in experimental pneumococcal meningitis

    PubMed Central

    Grandgirard, Denis; Valente, Luca G.; Täuber, Martin G.; Leib, Stephen L.

    2016-01-01

    Streptococcus pneumoniae bacteria can be characterized into over 90 serotypes according to the composition of their polysaccharide capsules. Some serotypes are common in nasopharyngeal carriage whereas others are associated with invasive disease, but when carriage serotypes do invade disease is often particularly severe. It is unknown whether disease severity is due directly to the capsule type or to other virulence factors. Here, we used a clinical pneumococcal isolate and its capsule-switch mutants to determine the effect of capsule, in isolation from the genetic background, on severity of meningitis in an infant rat model. We found that possession of a capsule was essential for causing meningitis. Serotype 6B caused significantly more mortality than 7F and this correlated with increased capsule thickness in the cerebrospinal fluid (CSF), a stronger inflammatory cytokine response in the CSF and ultimately more cortical brain damage. We conclude that capsule type has a direct effect on meningitis severity. This is an important consideration in the current era of vaccination targeting a subset of capsule types that causes serotype replacement. PMID:27009189

  5. SIMULTANEOUS PRODUCTION OF TWO CAPSULAR POLYSACCHARIDES BY PNEUMOCOCCUS

    PubMed Central

    Austrian, Robert; Bernheimer, Harriet P.; Smith, Evelyn E. B.; Mills, George T.

    1959-01-01

    Study of the capsular genome of pneumococcus has shown that it controls a multiplicity of biochemical reactions essential to the synthesis of capsular polysaccharide. Mutation affecting any one of several biochemical reactions concerned with capsular synthesis may result in loss of capsulation without alteration of other biochemical functions similarly concerned. Mutations affecting the synthesis of uronic acids are an important cause of loss of capsulation and of virulence by strains of pneumococcus Type I and Type III. The capsular genome appears to have a specific location in the total genome of the cell, this locus being occupied by the capsular genome of whatever capsular type is expressed by the cell. Transformation of capsulated or of non-capsulated pneumococci to heterologous capsular type results probably from a genetic exchange followed by the development of a new biosynthetic pathway in the transformed cell. The new capsular genome is transferred to the transformed cell as a single particle of DNA. Binary capsulation results from the simultaneous presence within the pneumococcal cell of two capsular genomes, one mutated, the other normal. Interaction between the biochemical pathways controlled by the two capsular genomes leads to augmentation of the phenotypic expression of the product controlled by one and to partial suppression of the product determined by the other. Knowledge of the biochemical basis of binary capsulation can be used to indicate the presence of uronic acid in the capsular polysaccharide of a pneurnococcal type the composition of the capsule of which is unknown. PMID:13795197

  6. Rupture of anterior lens capsule from blunt ocular injury.

    PubMed

    Banitt, Michael R; Malta, João B; Mian, Shahzad I; Soong, H Kaz

    2009-05-01

    We report 3 cases of blunt trauma causing rupture of the anterior lens capsule with cataract formation. The injuries were caused by a paintball gun, a ball-bearing air pistol, and an aluminum rivet. In all 3 cases, the anterior capsule tears were central and the posterior capsules and zonules intact; uneventful cataract extraction with implantation of an intraocular lens was performed. The postoperative visual acuities was 20/40 in 1 case and 20/20 in the other 2 cases. We propose that the anterior lens capsule may have been torn by direct contusion from rapid focal indentation of the cornea onto the lens (coup injury) or by a fluid-mechanical, anteriorly directed rebound of the vitreous, bursting open the anterior capsule (contrecoup injury).

  7. Identification of a functional capsule locus in Streptococcus mitis.

    PubMed

    Rukke, H V; Hegna, I K; Petersen, F C

    2012-04-01

    The polysaccharide capsule of Streptococcus pneumoniae is a hallmark for virulence in humans. In its close relative Streptococcus mitis, a common human commensal, analysis of the sequenced genomes of six strains revealed the presence of a putative capsule locus in four of them. We constructed an isogenic S. mitis mutant from the type strain that lacked the 19 open reading frames in the capsule locus (Δcps mutant), using a deletion strategy similar to previous capsule functional studies in S. pneumoniae. Transmission electron microscopy and atomic force microscopy revealed a capsule-like structure in the S. mitis type strain that was absent or reduced in the Δcps mutant. Since S. mitis are predominant oral colonizers of tooth surfaces, we addressed the relevance of the capsule locus for the S. mitis overall surface properties, autoaggregation and biofilm formation. The capsule deletion resulted in a mutant with approximately two-fold increase in hydrophobicity. Binding to the Stains-all cationic dye was reduced by 40%, suggesting a reduction in the overall negative surface charge of the mutant. The mutant exhibited also increased autoaggregation in coaggregation buffer, and up to six-fold increase in biofilm levels. The results suggested that the capsule locus is associated with production of a capsule-like structure in S. mitis and indicated that the S. mitis capsule-like structure may confer surface attributes similar to those associated with the capsule in S. pneumoniae.

  8. The Cryptococcus neoformans Capsule: a Sword and a Shield

    PubMed Central

    O'Meara, Teresa R.

    2012-01-01

    Summary: The human fungal pathogen Cryptococcus neoformans is characterized by its ability to induce a distinct polysaccharide capsule in response to a number of host-specific environmental stimuli. The induction of capsule is a complex biological process encompassing regulation at multiple steps, including the biosynthesis, transport, and maintenance of the polysaccharide at the cell surface. By precisely regulating the composition of its cell surface and secreted polysaccharides, C. neoformans has developed intricate ways to establish chronic infection and dormancy in the human host. The plasticity of the capsule structure in response to various host conditions also underscores the complex relationship between host and parasite. Much of this precise regulation of capsule is achieved through the transcriptional responses of multiple conserved signaling pathways that have been coopted to regulate this C. neoformans-specific virulence-associated phenotype. This review focuses on specific host stimuli that trigger the activation of the signal transduction cascades and on the downstream transcriptional responses that are required for robust encapsulation around the cell. PMID:22763631

  9. Pneumococcal Capsules and Their Types: Past, Present, and Future

    PubMed Central

    Geno, K. Aaron; Gilbert, Gwendolyn L.; Song, Joon Young; Skovsted, Ian C.; Klugman, Keith P.; Jones, Christopher; Konradsen, Helle B.

    2015-01-01

    SUMMARY Streptococcus pneumoniae (the pneumococcus) is an important human pathogen. Its virulence is largely due to its polysaccharide capsule, which shields it from the host immune system, and because of this, the capsule has been extensively studied. Studies of the capsule led to the identification of DNA as the genetic material, identification of many different capsular serotypes, and identification of the serotype-specific nature of protection by adaptive immunity. Recent studies have led to the determination of capsular polysaccharide structures for many serotypes using advanced analytical technologies, complete elucidation of genetic basis for the capsular types, and the development of highly effective pneumococcal conjugate vaccines. Conjugate vaccine use has altered the serotype distribution by either serotype replacement or switching, and this has increased the need to serotype pneumococci. Due to great advances in molecular technologies and our understanding of the pneumococcal genome, molecular approaches have become powerful tools to predict pneumococcal serotypes. In addition, more-precise and -efficient serotyping methods that directly detect polysaccharide structures are emerging. These improvements in our capabilities will greatly enhance future investigations of pneumococcal epidemiology and diseases and the biology of colonization and innate immunity to pneumococcal capsules. PMID:26085553

  10. Pneumococcal Capsules and Their Types: Past, Present, and Future.

    PubMed

    Geno, K Aaron; Gilbert, Gwendolyn L; Song, Joon Young; Skovsted, Ian C; Klugman, Keith P; Jones, Christopher; Konradsen, Helle B; Nahm, Moon H

    2015-07-01

    Streptococcus pneumoniae (the pneumococcus) is an important human pathogen. Its virulence is largely due to its polysaccharide capsule, which shields it from the host immune system, and because of this, the capsule has been extensively studied. Studies of the capsule led to the identification of DNA as the genetic material, identification of many different capsular serotypes, and identification of the serotype-specific nature of protection by adaptive immunity. Recent studies have led to the determination of capsular polysaccharide structures for many serotypes using advanced analytical technologies, complete elucidation of genetic basis for the capsular types, and the development of highly effective pneumococcal conjugate vaccines. Conjugate vaccine use has altered the serotype distribution by either serotype replacement or switching, and this has increased the need to serotype pneumococci. Due to great advances in molecular technologies and our understanding of the pneumococcal genome, molecular approaches have become powerful tools to predict pneumococcal serotypes. In addition, more-precise and -efficient serotyping methods that directly detect polysaccharide structures are emerging. These improvements in our capabilities will greatly enhance future investigations of pneumococcal epidemiology and diseases and the biology of colonization and innate immunity to pneumococcal capsules. PMID:26085553

  11. Surface Polysaccharide Mutants Reveal that Absence of O Antigen Reduces Biofilm Formation of Actinobacillus pleuropneumoniae

    PubMed Central

    Hathroubi, S.; Hancock, M. A.; Langford, P. R.; Tremblay, Y. D. N.; Labrie, J.

    2015-01-01

    Actinobacillus pleuropneumoniae is a Gram-negative bacterium belonging to the Pasteurellaceae family and the causative agent of porcine pleuropneumonia, a highly contagious lung disease causing important economic losses. Surface polysaccharides, including lipopolysaccharides (LPS) and capsular polysaccharides (CPS), are implicated in the adhesion and virulence of A. pleuropneumoniae, but their role in biofilm formation is still unclear. In this study, we investigated the requirement for these surface polysaccharides in biofilm formation by A. pleuropneumoniae serotype 1. Well-characterized mutants were used: an O-antigen LPS mutant, a truncated core LPS mutant with an intact O antigen, a capsule mutant, and a poly-N-acetylglucosamine (PGA) mutant. We compared the amount of biofilm produced by the parental strain and the isogenic mutants using static and dynamic systems. Compared to the findings for the biofilm of the parental or other strains, the biofilm of the O antigen and the PGA mutants was dramatically reduced, and it had less cell-associated PGA. Real-time PCR analyses revealed a significant reduction in the level of pgaA, cpxR, and cpxA mRNA in the biofilm cells of the O-antigen mutant compared to that in the biofilm cells of the parental strain. Specific binding between PGA and LPS was consistently detected by surface plasmon resonance, but the lack of O antigen did not abolish these interactions. In conclusion, the absence of the O antigen reduces the ability of A. pleuropneumoniae to form a biofilm, and this is associated with the reduced expression and production of PGA. PMID:26483403

  12. Surface Polysaccharide Mutants Reveal that Absence of O Antigen Reduces Biofilm Formation of Actinobacillus pleuropneumoniae.

    PubMed

    Hathroubi, S; Hancock, M A; Bossé, J T; Langford, P R; Tremblay, Y D N; Labrie, J; Jacques, M

    2016-01-01

    Actinobacillus pleuropneumoniae is a Gram-negative bacterium belonging to the Pasteurellaceae family and the causative agent of porcine pleuropneumonia, a highly contagious lung disease causing important economic losses. Surface polysaccharides, including lipopolysaccharides (LPS) and capsular polysaccharides (CPS), are implicated in the adhesion and virulence of A. pleuropneumoniae, but their role in biofilm formation is still unclear. In this study, we investigated the requirement for these surface polysaccharides in biofilm formation by A. pleuropneumoniae serotype 1. Well-characterized mutants were used: an O-antigen LPS mutant, a truncated core LPS mutant with an intact O antigen, a capsule mutant, and a poly-N-acetylglucosamine (PGA) mutant. We compared the amount of biofilm produced by the parental strain and the isogenic mutants using static and dynamic systems. Compared to the findings for the biofilm of the parental or other strains, the biofilm of the O antigen and the PGA mutants was dramatically reduced, and it had less cell-associated PGA. Real-time PCR analyses revealed a significant reduction in the level of pgaA, cpxR, and cpxA mRNA in the biofilm cells of the O-antigen mutant compared to that in the biofilm cells of the parental strain. Specific binding between PGA and LPS was consistently detected by surface plasmon resonance, but the lack of O antigen did not abolish these interactions. In conclusion, the absence of the O antigen reduces the ability of A. pleuropneumoniae to form a biofilm, and this is associated with the reduced expression and production of PGA. PMID:26483403

  13. Capsule enlargement in Cryptococcus neoformans confers resistance to oxidative stress suggesting a mechanism for intracellular survival.

    PubMed

    Zaragoza, Oscar; Chrisman, Cara J; Castelli, Maria Victoria; Frases, Susana; Cuenca-Estrella, Manuel; Rodríguez-Tudela, Juan Luis; Casadevall, Arturo

    2008-10-01

    Cryptococcus neoformans is a facultative intracellular pathogen. The most distinctive feature of C. neoformans is a polysaccharide capsule that enlarges depending on environmental stimuli. The mechanism by which C. neoformans avoids killing during phagocytosis is unknown. We hypothesized that capsule growth conferred resistance to microbicidal molecules produced by the host during infection, particularly during phagocytosis. We observed that capsule enlargement conferred resistance to reactive oxygen species produced by H(2)O(2) that was not associated with a higher catalase activity, suggesting a new function for the capsule as a scavenger of reactive oxidative intermediates. Soluble capsular polysaccharide protected C. neoformans and Saccharomyces cerevisiae from killing by H(2)O(2). Acapsular mutants had higher susceptibility to free radicals. Capsular polysaccharide acted as an antioxidant in the nitroblue tetrazolium (NBT) reduction coupled to beta-nicotinamide adenine dinucleotide (NADH)/phenazine methosulfate (PMS) assay. Capsule enlargement conferred resistance to antimicrobial peptides and the antifungal drug Amphotericin B. Interestingly, the capsule had no effect on susceptibility to azoles and increased susceptibility to fluconazole. Capsule enlargement reduced phagocytosis by environmental predators, although we also noticed that in this system, starvation of C. neoformans cells produced resistance to phagocytosis. Our results suggest that capsular enlargement is a mechanism that enhances C. neoformans survival when ingested by phagocytic cells.

  14. Capsule enlargement in Cryptococcus neoformans confers resistance to oxidative stress suggesting a mechanism for intracellular survival

    PubMed Central

    Zaragoza, Oscar; Chrisman, Cara J.; Castelli, Maria Victoria; Frases, Susana; Cuenca-Estrella, Manuel; Rodríguez-Tudela, Juan Luis; Casadevall, Arturo

    2015-01-01

    Summary Cryptococcus neoformans is a facultative intracellular pathogen. The most distinctive feature of C. neoformans is a polysaccharide capsule that enlarges depending on environmental stimuli. The mechanism by which C. neoformans avoids killing during phagocytosis is unknown. We hypothesized that capsule growth conferred resistance to microbicidal molecules produced by the host during infection, particularly during phagocytosis. We observed that capsule enlargement conferred resistance to reactive oxygen species produced by H2O2 that was not associated with a higher catalase activity, suggesting a new function for the capsule as a scavenger of reactive oxidative intermediates. Soluble capsular polysaccharide protected C. neoformans and Saccharomyces cerevisiae from killing by H2O2. Acapsular mutants had higher susceptibility to free radicals. Capsular polysaccharide acted as an antioxidant in the nitroblue tetrazolium (NBT) reduction coupled to β-nicotinamide adenine dinucleotide (NADH)/phenazine methosulfate (PMS) assay. Capsule enlargement conferred resistance to antimicrobial peptides and the antifungal drug Amphotericin B. Interestingly, the capsule had no effect on susceptibility to azoles and increased susceptibility to fluconazole. Capsule enlargement reduced phagocytosis by environmental predators, although we also noticed that in this system, starvation of C. neoformans cells produced resistance to phagocytosis. Our results suggest that capsular enlargement is a mechanism that enhances C. neoformans survival when ingested by phagocytic cells. PMID:18554313

  15. The Vi capsular polysaccharide prevents complement receptor 3-mediated clearance of Salmonella enterica serotype Typhi.

    PubMed

    Wilson, R Paul; Winter, Sebastian E; Spees, Alanna M; Winter, Maria G; Nishimori, Jessalyn H; Sanchez, Jesus F; Nuccio, Sean-Paul; Crawford, Robert W; Tükel, Çagla; Bäumler, Andreas J

    2011-02-01

    Capsular polysaccharides are important virulence factors of invasive bacterial pathogens. Here we studied the role of the virulence (Vi) capsular polysaccharide of Salmonella enterica serotype Typhi (S. Typhi) in preventing innate immune recognition by complement. Comparison of capsulated S. Typhi with a noncapsulated mutant (ΔtviBCDE vexABCDE mutant) revealed that the Vi capsule interfered with complement component 3 (C3) deposition. Decreased complement fixation resulted in reduced bacterial binding to complement receptor 3 (CR3) on the surface of murine macrophages in vitro and decreased CR3-dependent clearance of Vi capsulated S. Typhi from the livers and spleens of mice. Opsonization of bacteria with immune serum prior to intraperitoneal infection increased clearance of capsulated S. Typhi from the liver. Our data suggest that the Vi capsule prevents CR3-dependent clearance, which can be overcome in part by a specific antibody response.

  16. Networks of fibers and factors: regulation of capsule formation in Cryptococcus neoformans.

    PubMed

    Ding, Hao; Mayer, François L; Sánchez-León, Eddy; de S Araújo, Glauber R; Frases, Susana; Kronstad, James W

    2016-01-01

    The ability of the pathogenic fungus Cryptococcus neoformans to cause life-threatening meningoencephalitis in immunocompromised individuals is due in large part to elaboration of a capsule consisting of polysaccharide fibers. The size of the cell-associated capsule is remarkably responsive to a variety of environmental and host conditions, but the mechanistic details of the regulation, synthesis, trafficking, and attachment of the polysaccharides are poorly understood. Recent studies reveal a complex network of transcription factors that influence capsule elaboration in response to several different signals of relevance to disease (e.g., iron deprivation). The emerging complexity of the network is consistent with the diversity of conditions that influence the capsule and illustrates the responsiveness of the fungus to both the environment and mammalian hosts. PMID:27516877

  17. Networks of fibers and factors: regulation of capsule formation in Cryptococcus neoformans.

    PubMed

    Ding, Hao; Mayer, François L; Sánchez-León, Eddy; de S Araújo, Glauber R; Frases, Susana; Kronstad, James W

    2016-01-01

    The ability of the pathogenic fungus Cryptococcus neoformans to cause life-threatening meningoencephalitis in immunocompromised individuals is due in large part to elaboration of a capsule consisting of polysaccharide fibers. The size of the cell-associated capsule is remarkably responsive to a variety of environmental and host conditions, but the mechanistic details of the regulation, synthesis, trafficking, and attachment of the polysaccharides are poorly understood. Recent studies reveal a complex network of transcription factors that influence capsule elaboration in response to several different signals of relevance to disease (e.g., iron deprivation). The emerging complexity of the network is consistent with the diversity of conditions that influence the capsule and illustrates the responsiveness of the fungus to both the environment and mammalian hosts.

  18. Networks of fibers and factors: regulation of capsule formation in Cryptococcus neoformans

    PubMed Central

    de S. Araújo, Glauber R.; Frases, Susana; Kronstad, James W.

    2016-01-01

    The ability of the pathogenic fungus Cryptococcus neoformans to cause life-threatening meningoencephalitis in immunocompromised individuals is due in large part to elaboration of a capsule consisting of polysaccharide fibers. The size of the cell-associated capsule is remarkably responsive to a variety of environmental and host conditions, but the mechanistic details of the regulation, synthesis, trafficking, and attachment of the polysaccharides are poorly understood. Recent studies reveal a complex network of transcription factors that influence capsule elaboration in response to several different signals of relevance to disease (e.g., iron deprivation). The emerging complexity of the network is consistent with the diversity of conditions that influence the capsule and illustrates the responsiveness of the fungus to both the environment and mammalian hosts. PMID:27516877

  19. Lipophilic dye staining of Cryptococcus neoformans extracellular vesicles and capsule.

    PubMed

    Nicola, André Moraes; Frases, Susana; Casadevall, Arturo

    2009-09-01

    Cryptococcus neoformans is an encapsulated yeast that causes systemic mycosis in immunosuppressed individuals. Recent studies have determined that this fungus produces vesicles that are released to the extracellular environment both in vivo and in vitro. These vesicles contain assorted cargo that includes several molecules associated with virulence and implicated in host-pathogen interactions, such as capsular polysaccharides, laccase, urease, and other proteins. To date, visualization of extracellular vesicles has relied on transmission electron microscopy, a time-consuming technique. In this work we report the use of fluorescent membrane tracers to stain lipophilic structures in cryptococcal culture supernatants and capsules. Two dialkylcarbocyanine probes with different spectral characteristics were used to visualize purified vesicles by fluorescence microscopy and flow cytometry. Dual staining of vesicles with dialkylcarbocyanine and RNA-selective nucleic acid dyes suggested that a fraction of the vesicle population carried RNA. Use of these dyes to stain whole cells, however, was hampered by their possible direct binding to capsular polysaccharide. A fluorescent phospholipid was used as additional membrane tracer to stain whole cells, revealing punctate structures on the edge of the capsule which are consistent with vesicular trafficking. Lipophilic dyes provide new tools for the study of fungal extracellular vesicles and their content. The finding of hydrophobic regions in the capsule of C. neoformans adds to the growing evidence for a structurally complex structure composed of polysaccharide and nonpolysaccharide components.

  20. The Lens Capsule

    PubMed Central

    Danysh, Brian P.; Duncan, Melinda K.

    2009-01-01

    The lens capsule is a modified basement membrane that completely surrounds the ocular lens. It is known that this extracellular matrix is important for both the structure and biomechanics of the lens in addition to providing informational cues to maintain lens cell phenotype. This review covers the development and structure of the lens capsule, lens diseases associated with mutations in extracellular matrix genes and the role of the capsule in lens function including those proposed for visual accommodation, selective permeability to infectious agents, and cell signaling. PMID:18773892

  1. Masquerading microbial pathogens: Capsular polysaccharides mimic host-tissue molecules

    PubMed Central

    Cress, Brady F.; Englaender, Jacob A.; He, Wenqin; Kasper, Dennis; Linhardt, Robert J.; Koffas, Mattheos A. G.

    2014-01-01

    Summary Bacterial pathogens bearing capsular polysaccharides identical to mammalian glycans benefit from an additional level of protection from host immune response. The increasing prevalence of antibiotic resistant bacteria portends an impending post-antibiotic age, characterized by diminishing efficacy of common antibiotics and routine application of multifaceted, complementary therapeutic approaches to treat bacterial infections, particularly multidrug-resistant organisms. The first line of defense for most bacterial pathogens consists of a physical and immunological barrier known as the capsule, commonly composed of a viscous layer of carbohydrates that are covalently bound to the cell wall in Gram-positive bacteria or often to lipids of the outer membrane in many Gram-negative bacteria. Bacterial capsular polysaccharides are a diverse class of high molecular weight polysaccharides contributing to virulence of many human pathogens in the gut, respiratory tree, urinary tract, and other host tissues, by hiding cell-surface components that might otherwise elicit host immune response. This review highlights capsular polysaccharides that are structurally identical or similar to polysaccharides found in mammalian tissues, including polysialic acid and glycosaminoglycan capsules hyaluronan, heparosan, and chondroitin. Such non-immunogenic coatings render pathogens insensitive to certain immune responses, effectively increasing residence time in host tissues and enabling pathologically relevant population densities to be reached. Biosynthetic pathways and capsular involvement in immune system evasion are described providing a basis for potential therapies aimed at supplementing or replacing antibiotic treatment. PMID:24372337

  2. Protective role of the capsule and impact of serotype 4 switching on Streptococcus mitis.

    PubMed

    Rukke, Håkon V; Kalluru, Raja Sab; Repnik, Urska; Gerlini, Alice; José, Ricardo J; Periselneris, Jimstan; Marshall, Helina; Griffiths, Gareth; Oggioni, Marco Rinaldo; Brown, Jeremy S; Petersen, Fernanda C

    2014-09-01

    The polysaccharide capsule surrounding Streptococcus pneumoniae is essential for virulence. Recently, Streptococcus mitis, a human commensal and a close relative of S. pneumoniae, was also shown to have a capsule. In this study, the S. mitis type strain switched capsule by acquisition of the serotype 4 capsule locus of S. pneumoniae TIGR4, following induction of competence for natural transformation. Comparison of the wild type with the capsule-switching mutant and with a capsule deletion mutant showed that the capsule protected S. mitis against phagocytosis by RAW 264.7 macrophages. This effect was enhanced in the S. mitis strain expressing the S. pneumoniae capsule, which showed, in addition, increased resistance against early clearance in a mouse model of lung infection. Expression of both capsules also favored survival in human blood, and the effect was again more pronounced for the capsule-switching mutant. S. mitis survival in horse blood or in a mouse model of bacteremia was not significantly different between the wild type and the mutant strains. In all models, S. pneumoniae TIGR4 showed higher rates of survival than the S. mitis type strain or the capsule-switching mutant, except in the lung model, in which significant differences between S. pneumoniae TIGR4 and the capsule-switching mutant were not observed. Thus, we identified conditions that showed a protective function for the capsule in S. mitis. Under such conditions, S. mitis resistance to clearance could be enhanced by capsule switching to serotype 4, but it was enhanced to levels lower than those for the virulent strain S. pneumoniae TIGR4. PMID:24958712

  3. Wzy-dependent bacterial capsules as potential drug targets.

    PubMed

    Ericsson, Daniel J; Standish, Alistair; Kobe, Bostjan; Morona, Renato

    2012-10-01

    The bacterial capsule is a recognized virulence factor in pathogenic bacteria. It likely works as an antiphagocytic barrier by minimizing complement deposition on the bacterial surface. With the continual rise of bacterial pathogens resistant to multiple antibiotics, there is an increasing need for novel drugs. In the Wzy-dependent pathway, the biosynthesis of capsular polysaccharide (CPS) is regulated by a phosphoregulatory system, whose main components consist of bacterial-tyrosine kinases (BY-kinases) and their cognate phosphatases. The ability to regulate capsule biosynthesis has been shown to be vital for pathogenicity, because different stages of infection require a shift in capsule thickness, making the phosphoregulatory proteins suitable as drug targets. Here, we review the role of regulatory proteins focusing on Streptococcus pneumoniae, Staphylococcus aureus, and Escherichia coli and discuss their suitability as targets in structure-based drug design.

  4. Evasion of Innate Immune Responses by the Highly Virulent Cryptococcus gattii by Altering Capsule Glucuronoxylomannan Structure

    PubMed Central

    Urai, Makoto; Kaneko, Yukihiro; Ueno, Keigo; Okubo, Yoichiro; Aizawa, Tomoko; Fukazawa, Hidesuke; Sugita, Takashi; Ohno, Hideaki; Shibuya, Kazutoshi; Kinjo, Yuki; Miyazaki, Yoshitsugu

    2016-01-01

    Cryptococcus neoformans causes life-threatening diseases mainly in immunosuppressed hosts such as AIDS patients; C. gattii causes disseminated infections even in healthy hosts. To identify the possible molecular mechanisms underlying this difference in virulence, we investigated the survival and histopathology of lung tissue in wild-type and CD4-depleted mice infected with C. neoformans H99 and C. gattii JP02 (the highly virulent strain isolated in Japan); we then compared dendritic cell (DC) cytokine release responses to different cell fractions from these two strains. JP02-infected mice exhibited shorter survival and fewer inflammatory cells in the lung than H99-infected control mice. Depletion of CD4-related cellular immunity reduced survival of H99-infected mice but had no effect on the survival or inflammatory cell infiltration in JP02-infected mice, suggesting that JP02 evades immune detection. To identify the molecule(s) conferring this difference, we measured cytokine production from murine DCs co-cultured with H99 and JP02 in vitro. The levels of inflammatory cytokines from DCs treated with intact JP02 cells, the extracted capsule, secreted extracellular polysaccharides, and purified glucuronoxylomannan (GXM) were markedly lower than those induced by intact H99 cells and corresponding H99 fractions. Structural analysis of GXM indicated that JP02 altered one of two O-acetyl groups detected in the H99 GXM. Deacetylated GXM lost the ability to induce inflammatory cytokine release from DCs, implicating these O-acetyl groups in immune recognition. We conclude that the highly virulent C. gattii processes a structural alteration in GXM that allows this pathogen to evade the immune response and therefore elimination. PMID:26779451

  5. The Cryptococcus neoformans capsule: lessons from the use of optical tweezers and other biophysical tools

    PubMed Central

    Pontes, Bruno; Frases, Susana

    2015-01-01

    The fungal pathogen Cryptococcus neoformans causes life-threatening infections in immunocompromised individuals, representing one of the leading causes of morbidity and mortality in AIDS patients. The main virulence factor of C. neoformans is the polysaccharide capsule; however, many fundamental aspects of capsule structure and function remain poorly understood. Recently, important capsule properties were uncovered using optical tweezers and other biophysical techniques, including dynamic and static light scattering, zeta potential and viscosity analysis. This review provides an overview of the latest findings in this emerging field, explaining the impact of these findings on our understanding of C. neoformans biology and resistance to host immune defenses. PMID:26157436

  6. The Cryptococcus neoformans capsule: lessons from the use of optical tweezers and other biophysical tools.

    PubMed

    Pontes, Bruno; Frases, Susana

    2015-01-01

    The fungal pathogen Cryptococcus neoformans causes life-threatening infections in immunocompromised individuals, representing one of the leading causes of morbidity and mortality in AIDS patients. The main virulence factor of C. neoformans is the polysaccharide capsule; however, many fundamental aspects of capsule structure and function remain poorly understood. Recently, important capsule properties were uncovered using optical tweezers and other biophysical techniques, including dynamic and static light scattering, zeta potential and viscosity analysis. This review provides an overview of the latest findings in this emerging field, explaining the impact of these findings on our understanding of C. neoformans biology and resistance to host immune defenses.

  7. Method for producing capsular polysaccharides

    NASA Technical Reports Server (NTRS)

    Kern, Roger G. (Inventor); Petersen, Gene R. (Inventor); Richards, Gil F. (Inventor)

    1994-01-01

    Structurally altered capsular polysaccharides are produced by mutant bacteria. These polysaccharides are isolated by selecting a wild type bacterial strain and a phage producing degradative enzymes that have substrate specificity for the capsular polysaccharides produced by the wild type bacteria. Phage-resistant mutants producing capsular polysaccharides are selected and the structurally altered capsular polysaccharide is isolated therefrom.

  8. Cellular charge of Cryptococcus neoformans: contributions from the capsular polysaccharide, melanin, and monoclonal antibody binding.

    PubMed Central

    Nosanchuk, J D; Casadevall, A

    1997-01-01

    Cryptococcus neoformans is a human pathogenic fungus which is unusual in two respects: it has a polysaccharide capsule similar to that found in encapsulated bacteria and it can produce melanin. Capsular and melanization phenotypes are associated with virulence. In this study we analyzed the contributions of the capsular polysaccharide, melanization, and antibody binding to the capsule to the cellular charge of C. neoformans. Cell charge was inferred from measurements of zeta potential. The results indicate that (i) C. neoformans cells are significantly more negatively charged than Saccharomyces cerevisiae cells, (ii) the polysaccharide capsule of C. neoformans is responsible for the high negative charge of the cells, (iii) C. neoformans melanin is negatively charged, (iv) melanization in C. neoformans is associated with an increased negative charge per cell, and (v) antibody binding to the capsule of C. neoformans significantly alters the cell charge. These results suggest that alterations in cell charge attributable to polysaccharide capsule formation, melanization, and antibody binding may affect C. neoformans virulence given that macrophage phagocytosis is effected by the zeta potential of microorganisms. PMID:9125569

  9. Variation at the capsule locus, cps, of mistyped and non-typable Streptococcus pneumoniae isolates.

    PubMed

    Salter, S J; Hinds, J; Gould, K A; Lambertsen, L; Hanage, W P; Antonio, M; Turner, P; Hermans, P W M; Bootsma, H J; O'Brien, K L; Bentley, S D

    2012-06-01

    The capsule polysaccharide locus (cps) is the site of the capsule biosynthesis gene cluster in encapsulated Streptococcus pneumoniae. A set of pneumococcal samples and non-pneumococcal streptococci from Denmark, the Gambia, the Netherlands, Thailand, the UK and the USA were sequenced at the cps locus to elucidate serologically mistyped or non-typable isolates. We identified a novel serotype 33B/33C mosaic capsule cluster and previously unseen serotype 22F capsule genes, disrupted and deleted cps clusters, the presence of aliB and nspA genes that are unrelated to capsule production, and similar genes in the non-pneumococcal samples. These data provide greater understanding of diversity at a locus which is crucial to the antigenic diversity of the pathogen and current vaccine strategies.

  10. Chemical Modification of Polysaccharides

    PubMed Central

    Cumpstey, Ian

    2013-01-01

    This review covers methods for modifying the structures of polysaccharides. The introduction of hydrophobic, acidic, basic, or other functionality into polysaccharide structures can alter the properties of materials based on these substances. The development of chemical methods to achieve this aim is an ongoing area of research that is expected to become more important as the emphasis on using renewable starting materials and sustainable processes increases in the future. The methods covered in this review include ester and ether formation using saccharide oxygen nucleophiles, including enzymatic reactions and aspects of regioselectivity; the introduction of heteroatomic nucleophiles into polysaccharide chains; the oxidation of polysaccharides, including oxidative glycol cleavage, chemical oxidation of primary alcohols to carboxylic acids, and enzymatic oxidation of primary alcohols to aldehydes; reactions of uronic-acid-based polysaccharides; nucleophilic reactions of the amines of chitosan; and the formation of unsaturated polysaccharide derivatives. PMID:24151557

  11. (Photosynthesis in intact plants)

    SciTech Connect

    Not Available

    1990-01-01

    Progress in the two years since the last renewal application has been excellent. We have made substantial contributions on both main fronts of the projects, and are particularly happy with the progress of our research on intact plants. The approach of basing our field work on a sound foundation of laboratory studies has enabled is to use methods which provide unambiguous assays of well characterized reactions. We have also made excellent progress in several laboratory studies which will have direct applications in future field work, and have introduced to the laboratory a range of molecular genetics techniques which will allow us to explore new options in the attempt to understand function at the level of molecular structure.

  12. Advances in Capsule Endoscopy

    PubMed Central

    Scott, Ryan

    2015-01-01

    Wireless video capsule endoscopy (VCE) is a minimally invasive technology that has revolutionized the approach to small intestinal disease investigation and management. Designed primarily to provide diagnostic imaging of the small intestine, VCE is used predominantly for obscure gastrointestinal bleeding and suspected Crohn’s disease; however, numerous other indications have been established, including the assessment of celiac disease, investigation of small bowel tumors, and surveillance of hereditary polyposis syndromes. Since the introduction of small bowel VCE in 2000, more than 1600 articles have been published describing the evolution of this technology. The main adverse outcome is capsule retention, which can potentially be avoided by careful patient selection or by using a patency capsule. Despite the numerous advances in the past 15 years, limitations such as incomplete VCE studies, missed lesions, and time-consuming reporting remain. The inability to control capsule movement for the application of targeted therapy or the acquisition of tissue for histologic analysis remains among the greatest challenges in the further development of capsule technology. This article outlines the recent technological and clinical advances in VCE and the future directions of research in this field. PMID:27482183

  13. Advances in Capsule Endoscopy.

    PubMed

    Scott, Ryan; Enns, Robert

    2015-09-01

    Wireless video capsule endoscopy (VCE) is a minimally invasive technology that has revolutionized the approach to small intestinal disease investigation and management. Designed primarily to provide diagnostic imaging of the small intestine, VCE is used predominantly for obscure gastrointestinal bleeding and suspected Crohn's disease; however, numerous other indications have been established, including the assessment of celiac disease, investigation of small bowel tumors, and surveillance of hereditary polyposis syndromes. Since the introduction of small bowel VCE in 2000, more than 1600 articles have been published describing the evolution of this technology. The main adverse outcome is capsule retention, which can potentially be avoided by careful patient selection or by using a patency capsule. Despite the numerous advances in the past 15 years, limitations such as incomplete VCE studies, missed lesions, and time-consuming reporting remain. The inability to control capsule movement for the application of targeted therapy or the acquisition of tissue for histologic analysis remains among the greatest challenges in the further development of capsule technology. This article outlines the recent technological and clinical advances in VCE and the future directions of research in this field. PMID:27482183

  14. Buckling of spherical capsules.

    PubMed

    Knoche, Sebastian; Kierfeld, Jan

    2011-10-01

    We investigate buckling of soft elastic capsules under negative pressure or for reduced capsule volume. Based on nonlinear shell theory and the assumption of a hyperelastic capsule membrane, shape equations for axisymmetric and initially spherical capsules are derived and solved numerically. A rich bifurcation behavior is found, which is presented in terms of bifurcation diagrams. The energetically preferred stable configuration is deduced from a least-energy principle both for prescribed volume and prescribed pressure. We find that buckled shapes are energetically favorable already at smaller negative pressures and larger critical volumes than predicted by the classical buckling instability. By preventing self-intersection for strongly reduced volume, we obtain a complete picture of the buckling process and can follow the shape from the initial undeformed state through the buckling instability into the fully collapsed state. Interestingly, the sequences of bifurcations and stable capsule shapes differ for prescribed volume and prescribed pressure. In the buckled state, we find a relation between curvatures at the indentation rim and the bending modulus, which can be used to determine elastic moduli from experimental shape analysis. PMID:22181297

  15. Hollow Microporous Organic Capsules

    PubMed Central

    Li, Buyi; Yang, Xinjia; Xia, Lingling; Majeed, Muhammad Irfan; Tan, Bien

    2013-01-01

    Fabrication of hollow microporous organic capsules (HMOCs) could be very useful because of their hollow and porous morphology, which combines the advantages of both microporous organic polymers and non-porous nanocapsules. They can be used as storage materials or reaction chambers while supplying the necessary path for the design of controlled uptake/release systems. Herein, the synthesis of HMOCs with high surface area through facile emulsion polymerization and hypercrosslinking reactions, is described. Due to their tailored porous structure, these capsules possessed high drug loading efficiency, zero-order drug release kinetics and are also demonstrated to be used as nanoscale reactors for the prepareation of nanoparticles (NPs) without any external stabilizer. Moreover, owing to their intrinsic biocompatibility and fluorescence, these capsules exhibit promising prospect for biomedical applications. PMID:23820511

  16. NIF capsule design update

    SciTech Connect

    Dittrich, T.R.; Haan, S.W.; Pollaine, S.; Burnham, A.K.; Strobel, G.L.

    1996-10-01

    We describe several ignition capsule designs, for use in the National Ignition Facility. We will compare these designs for ablator efficiency, ignition margin, implosion and stability performance. This study includes capsule designs driven by x-ray drive profiles with both 300 eV and 250 eV peak temperatures. All of the 300 eV designs are tuned to implode the DT fuel in a nearly identical manner. Capsule designs consist of an ablator material (CH with Br dopant; Be with Cu dopant; and B{sub 4}C) encasing a layer of solid DT. The dopants alter material opacities sufficiently to (1) shield the DT fuel from preheat effects; and (2) develop an ablation front density profile favorable to implosion stability. B{sub 4}C has sufficient opacity at 300 eV that a dopant is not necessary. Issues relating to material properties and fabrication will be described.

  17. Composition of the Capsular and Extracellular Polysaccharides of Rhizobium japonicum

    PubMed Central

    Mort, Andrew J.; Bauer, Wolfgang D.

    1980-01-01

    The chemical compositions of the capsular and extracellular polysaccharides of two strains of Rhizobium japonicum (311b 138 and 110) have been determined and correlated as a function of culture age with the ability of the bacteria from which they were obtained to bind soybean seed lectin. Each of the polysaccharides contains approximately constant amounts of mannosyl, glucosyl, and galacturonosyl residues in a molar ratio of 1:2:1. In addition they contain variable amounts of galactosyl and 4-O-methyl galactosyl residues. The total of galactose plus 4-O-methyl galactose, however, is constant and equivalent to the amount of mannose, indicating that the 4-O-methyl galactose residues arise by methylation of galactose residues in the polysaccharides. In both strains the proportion of galactose to methyl galactose is considerably greater in the polysaccharide from bacteria which do bind lectin than in the polysaccharide from bacteria which do not bind lectin. In addition to the changes in polysaccharide composition, there is a reduction of about 50% in the percentage of cells which are encapsulated as the cultures mature from early to late log phase. Since only capsulated cells bind lectin, the combination of the change in capsular composition and loss of encapsulation is probably sufficient to account for the loss of lectin binding capacity during growth of cultures of Rhizobium japonicum 311b 138 and 110. Images PMID:16661379

  18. Cryptococcus neoformans responds to mannitol by increasing capsule size in vitro and in vivo.

    PubMed

    Guimarães, Allan Jefferson; Frases, Susana; Cordero, Radamés J B; Nimrichter, Leonardo; Casadevall, Arturo; Nosanchuk, Joshua D

    2010-06-01

    The polysaccharide capsule of the fungus Cryptococcus neoformans is its main virulence factor. In this study, we determined the effects of mannitol and glucose on the capsule and exopolysaccharide production. Growth in mannitol significantly increased capsular volume compared with cultivation in glucose. However, cells grown in glucose concentrations higher than 62.5 mM produced more exopolysaccharide than cells grown in mannitol. The fibre lengths and glycosyl composition of capsular polysaccharide from yeast grown in mannitol was structurally different from that of yeast grown in glucose. Furthermore, mannitol treatment of mice infected intratracheally with C. neoformans resulted in fungal cells with significantly larger capsules and the mice had reduced fungal dissemination to the brain. Our results demonstrate the capacity of carbohydrate source and concentration to modify the expression of a major virulence factor of C. neoformans. These findings may impact the clinical management of cryptococcosis.

  19. Cryptococcus neoformans responds to mannitol by increasing capsule size in vitro and in vivo

    PubMed Central

    Guimarães, Allan Jefferson; Frases, Susana; Cordero, Radamés J. B.; Nimrichter, Leonardo; Casadevall, Arturo; Nosanchuk, Joshua D.

    2010-01-01

    The polysaccharide capsule of the fungus Cryptococcus neoformans is its main virulence factor. In this study, we determined the effects of mannitol and glucose on the capsule and exopolysaccharide production. Growth in mannitol significantly increased capsular volume compared to cultivation in glucose. However, cells grown in glucose concentrations higher than 62.5mM produced more exopolysaccharide than cells grown in mannitol. The fiber lengths and glycosyl composition of capsular polysaccharide from yeast grown in mannitol was structurally different from that of yeast grown in glucose. Furthermore, mannitol treatment of mice infected intratracheally with C. neoformans resulted in fungal cells with significantly larger capsules and the mice had reduced fungal dissemination to the brain. Our results demonstrate the capacity of carbohydrate source and concentration to modify the expression of a major virulence factor of C. neoformans. These findings may impact the clinical management of cryptococcosis. PMID:20070311

  20. Gelatin capsule in stomach (image)

    MedlinePlus

    ... detect the presence of intestinal parasites. A weighted gelatin capsule attached to a string is swallowed and left in place. After about 4 hours, the gelatin capsule is pulled out of the stomach by ...

  1. Fine Structure of Extracellular Polysaccharide of Erwinia amylovora†

    PubMed Central

    Politis, D. J.; Goodman, R. N.

    1980-01-01

    Virulent E9 and avirulent E8 strains of Erwinia amylovora were shown by means of light, transmission, and scanning microscopy to be, respectively, encapsulated and unencapsulated. Difficulty was encountered in stabilizing the fibrillar-appearing capsular extracellular polysaccharide. We suggest that the ephemeral nature of extracellular polysaccharide is due to the collapse of its extended structure upon dehydration. This occurs when bacteria are prepared for either transmission or scanning electron microscopy. The electron micrographs support our previous biochemical and immunological studies contending that the capsule is composed of tightly bound and loosely held components. The preparation of bacteria in freeze-dried colonies has permitted us to observe and explain the fluidity of the encapsulated strain. We suggest that this fluidity is a reflection of the loosely held extracellular polysaccharide or slime. Images PMID:16345638

  2. The physics of intact capture

    NASA Technical Reports Server (NTRS)

    Tsou, Peter; Griffiths, D. J.; Albee, A. L.

    1994-01-01

    The ability to capture projectiles intact at hypervelocities in underdense media open a new area of study in physics. Underdense material behaves markedly different than solid, liquid, or gas upon hypervelocity impact. This new phenomenon enables applications in science that would either not be possible or would be very costly by other means. This phenomenon has been fully demonstrated in the laboratory and validated in space. Even more interesting is the fact that this hypervelocity intact capture was accomplished passively. A better understanding of the physics of intact capture will lead to improvements in intact capture. A collection of physical observations of this phenomenon is presented here.

  3. Marine Origin Polysaccharides in Drug Delivery Systems

    PubMed Central

    Cardoso, Matias J.; Costa, Rui R.; Mano, João F.

    2016-01-01

    Oceans are a vast source of natural substances. In them, we find various compounds with wide biotechnological and biomedical applicabilities. The exploitation of the sea as a renewable source of biocompounds can have a positive impact on the development of new systems and devices for biomedical applications. Marine polysaccharides are among the most abundant materials in the seas, which contributes to a decrease of the extraction costs, besides their solubility behavior in aqueous solvents and extraction media, and their interaction with other biocompounds. Polysaccharides such as alginate, carrageenan and fucoidan can be extracted from algae, whereas chitosan and hyaluronan can be obtained from animal sources. Most marine polysaccharides have important biological properties such as biocompatibility, biodegradability, and anti-inflammatory activity, as well as adhesive and antimicrobial actions. Moreover, they can be modified in order to allow processing them into various shapes and sizes and may exhibit response dependence to external stimuli, such as pH and temperature. Due to these properties, these biomaterials have been studied as raw material for the construction of carrier devices for drugs, including particles, capsules and hydrogels. The devices are designed to achieve a controlled release of therapeutic agents in an attempt to fight against serious diseases, and to be used in advanced therapies, such as gene delivery or regenerative medicine. PMID:26861358

  4. Capsule injection system for a hydraulic capsule pipelining system

    DOEpatents

    Liu, Henry

    1982-01-01

    An injection system for injecting capsules into a hydraulic capsule pipelining system, the pipelining system comprising a pipeline adapted for flow of a carrier liquid therethrough, and capsules adapted to be transported through the pipeline by the carrier liquid flowing through the pipeline. The injection system comprises a reservoir of carrier liquid, the pipeline extending within the reservoir and extending downstream out of the reservoir, and a magazine in the reservoir for holding capsules in a series, one above another, for injection into the pipeline in the reservoir. The magazine has a lower end in communication with the pipeline in the reservoir for delivery of capsules from the magazine into the pipeline.

  5. Genome Sequence of a Neisseria meningitidis Capsule Null Locus Strain from the Clonal Complex of Sequence Type 198

    PubMed Central

    Schork, Sabine; Schlüter, Andreas; Blom, Jochen; Schneiker-Bekel, Susanne; Pühler, Alfred; Goesmann, Alexander; Frosch, Matthias

    2012-01-01

    Neisseria meningitidis is a commensal and accidental pathogen exclusively of humans. Although the production of polysaccharide capsules is considered to be essential for meningococcal virulence, there have been reports of constitutively unencapsulated strains causing invasive meningococcal disease (IMD). Here we report the genome sequence of a capsule null locus (cnl) strain of sequence type 198 (ST-198), which is found in half of the reported cases of IMD caused by cnl meningococcal strains. PMID:22933768

  6. Flow cytometric analysis of within-strain variation in polysaccharide expression by Bacteroides fragilis by use of murine monoclonal antibodies.

    PubMed

    Lutton, D A; Patrick, S; Crockard, A D; Stewart, L D; Larkin, M J; Dermott, E; McNeill, T A

    1991-10-01

    The reactivity of four different monoclonal antibodies (MAbs) with populations of Bacteroides fragilis NCTC 9343, enriched by density gradient centrifugation for a large capsule, small capsule and electron-dense layer (EDL) only visible by electronmicroscopy, was examined. The MAbs reacted strongly with polysaccharides present in both the large capsule- and EDL-enriched populations but not in the small capsule-enriched populations. The pattern of labelling was determined by immunoblotting, immunofluorescence and immuno-electronmicroscopy, and flow cytometry. The MAbs labelled cell membrane-associated epitopes in the large capsule- and EDL-enriched populations and cell-free material in the EDL population. By immunoblotting, ladders of repeating polysaccharide subunits were evident in the EDL population but not in the large capsule population. The proportion of cells labelled within each population was determined by flow cytometry. The reactivity of another MAb with the small capsule population was confirmed by flow cytometry. A qualitative indication of epitope expression was obtained by examination of the flow cytometric profiles. Differential expression of the same saccharide epitope was observed both between and within structurally distinct B. fragilis populations. The MAbs were species-specific and cross-reacted with several recent clinical isolates. These polysaccharides may be relevant to the virulence of B. fragilis. PMID:1719202

  7. Space research with intact organisms

    NASA Technical Reports Server (NTRS)

    Phillips, Robert W.; Haddy, Francis J.

    1992-01-01

    Effects of space exposure on intact organisms are briefly reviewed, and examples of future experiments that might provide new information on the role of gravity in the evolution of life are suggested. It is noted that long term experiments with intact plant and animals for studying gravitational thresholds will provide important new insights.

  8. An adhesive protein capsule of Escherichia coli.

    PubMed Central

    Orskov, I; Birch-Andersen, A; Duguid, J P; Stenderup, J; Orskov, F

    1985-01-01

    The nature of the adhesive capacity of three hemagglutinating Escherichia coli strains that had earlier been described as nonfimbriated was studied. The strains that were isolated from human disease adhered to human buccal and urinary tract epithelial cells, an adhesion that was not inhibited by D-mannose. By crossed immunoelectrophoresis it was shown that the three strains produced a common antigen, Z1, developed after growth at 37 degrees C but not 18 degrees C. One of the strains produced an additional antigen, Z2, of almost the same electrophoretic mobility in crossed immunoelectrophoresis. A mutant of this strain deficient of its polysaccharide K antigen had maintained the adhesive capacity, indicating that the K antigen was not responsible for adhesion. A further mutant of the acapsular mutant produced a strongly reduced amount of the Z antigens and had lost the ability to adhere. The Z1 (and Z2?) antigens were therefore deemed to be responsible for adhesion. In sodium dodecyl sulfate-polyacrylamide gel electrophoresis of extracts of cells of the three strains, a heavy Coomassie-blue stained line was seen, indicating the presence of a protein subunit of molecular weight slightly above 14,400. By immunoblotting with absorbed antiserum, it was shown that this protein was the same as that detected by crossed immunoelectrophoresis. Protease from Streptomyces griseus, but not trypsin, digested the protein. Heating to 100 degrees C did not affect it. By immunoelectron microscopy of embedded and sectioned bacteria that had first been treated with specific antisera and ferritin-labeled antirabbit immunoglobulin, the protein adhesin-antibody complex was found to surround the bacteria as a heavy capsule. After negative staining with uranylacetate (pH approximately 4), the capsule appeared as a mesh of very fine filaments. The possible role of this capsule in the pathogenesis of disease is discussed. Images PMID:2856913

  9. Capsule Growth in Cryptococcus neoformans Is Coordinated with Cell Cycle Progression

    PubMed Central

    García-Rodas, Rocío; Cordero, Radames J. B.; Trevijano-Contador, Nuria; Janbon, Guilhem; Moyrand, Frédérique; Casadevall, Arturo

    2014-01-01

    ABSTRACT The fungal pathogen Cryptococcus neoformans has several virulence factors, among which the most important is a polysaccharide capsule. The size of the capsule is variable and can increase significantly during infection. In this work, we investigated the relationship between capsular enlargement and the cell cycle. Capsule growth occurred primarily during the G1 phase. Real-time visualization of capsule growth demonstrated that this process occurred before the appearance of the bud and that capsule growth arrested during budding. Benomyl, which arrests the cells in G2/M, inhibited capsule growth, while sirolimus (rapamycin) addition, which induces G1 arrest, resulted in cells with larger capsule. Furthermore, we have characterized a mutant strain that lacks a putative G1/S cyclin. This mutant showed an increased capacity to enlarge the capsule, both in vivo (using Galleria mellonella as the host model) and in vitro. In the absence of Cln1, there was a significant increase in the production of extracellular vesicles. Proteomic assays suggest that in the cln1 mutant strain, there is an upregulation of the glyoxylate acid cycle. Besides, this cyclin mutant is avirulent at 37°C, which correlates with growth defects at this temperature in rich medium. In addition, the cln1 mutant showed lower intracellular replication rates in murine macrophages. We conclude that cell cycle regulatory elements are involved in the modulation of the expression of the main virulence factor in C. neoformans. PMID:24939886

  10. Effects of Lipopolysaccharide Biosynthesis Mutations on K1 Polysaccharide Association with the Escherichia coli Cell Surface

    PubMed Central

    Jiménez, Natalia; Senchenkova, Sofya N.; Knirel, Yuriy A.; Pieretti, Giuseppina; Corsaro, Maria M.; Aquilini, Eleonora; Regué, Miguel; Merino, Susana

    2012-01-01

    The presence of cell-bound K1 capsule and K1 polysaccharide in culture supernatants was determined in a series of in-frame nonpolar core biosynthetic mutants from Escherichia coli KT1094 (K1, R1 core lipopolysaccharide [LPS] type) for which the major core oligosaccharide structures were determined. Cell-bound K1 capsule was absent from mutants devoid of phosphoryl modifications on l-glycero-d-manno-heptose residues (HepI and HepII) of the inner-core LPS and reduced in mutants devoid of phosphoryl modification on HepII or devoid of HepIII. In contrast, in all of the mutants, K1 polysaccharide was found in culture supernatants. These results were confirmed by using a mutant with a deletion spanning from the hldD to waaQ genes of the waa gene cluster to which individual genes were reintroduced. A nuclear magnetic resonance (NMR) analysis of core LPS from HepIII-deficient mutants showed an alteration in the pattern of phosphoryl modifications. A cell extract containing both K1 capsule polysaccharide and LPS obtained from an O-antigen-deficient mutant could be resolved into K1 polysaccharide and core LPS by column chromatography only when EDTA and deoxycholate (DOC) buffer were used. These results suggest that the K1 polysaccharide remains cell associated by ionically interacting with the phosphate-negative charges of the core LPS. PMID:22522903

  11. In vitro and in vivo evaluation of a novel capsule for colon-specific drug delivery.

    PubMed

    Han, Min; Fang, Qiu-Li; Zhan, Hong-Wei; Luo, Tao; Liang, Wen-Quan; Gao, Jian-Qing

    2009-08-01

    The aim of this study was to estimate colon-specific drug delivery of a novel capsule (CS capsule). Theophylline was used as model drug and little was released from the CS capsules in the release medium mimicking physiological environment of stomach to small intestine. However, 66.7 +/- 8.8% theophylline was released from the capsules in the phosphate buffer (pH 6.8) mimicking the physiological environment of colon in the next 4 h, while the addition of galactomannanase (39.3 U/L) accelerated the disintegration of the CS capsule and enhanced the release rate to 92.6 +/- 6.0%. Rats in vivo pharmacokinetics demonstrated that the relative bioavailability of theophylline after intragastric administration of CS capsules was 76.72% with delayed T(max) of 8 h comparing to that of theophylline solution with T(max) of 1.5 h. Radiolabeled with technetium-99m, the CS capsule could keep intact from stomach to small intestine while disintegration of the CS capsule was observed in the proximal colon or the joint between the distal small intestine and right colon. A great quantity of radiolabeled marker was released as well as distributed in the whole colon at 10 h after administration. As a whole, the CS capsule prepared could provide an alternative carrier for the colon-specific drug delivery.

  12. Vesicular polysaccharide export in Cryptococcus neoformans is a eukaryotic solution to the problem of fungal trans-cell wall transport.

    PubMed

    Rodrigues, Marcio L; Nimrichter, Leonardo; Oliveira, Débora L; Frases, Susana; Miranda, Kildare; Zaragoza, Oscar; Alvarez, Mauricio; Nakouzi, Antonio; Feldmesser, Marta; Casadevall, Arturo

    2007-01-01

    The mechanisms by which macromolecules are transported through the cell wall of fungi are not known. A central question in the biology of Cryptococcus neoformans, the causative agent of cryptococcosis, is the mechanism by which capsular polysaccharide synthesized inside the cell is exported to the extracellular environment for capsule assembly and release. We demonstrate that C. neoformans produces extracellular vesicles during in vitro growth and animal infection. Vesicular compartments, which are transferred to the extracellular space by cell wall passage, contain glucuronoxylomannan (GXM), a component of the cryptococcal capsule, and key lipids, such as glucosylceramide and sterols. A correlation between GXM-containing vesicles and capsule expression was observed. The results imply a novel mechanism for the release of the major virulence factor of C. neoformans whereby polysaccharide packaged in lipid vesicles crosses the cell wall and the capsule network to reach the extracellular environment.

  13. Vesicular Polysaccharide Export in Cryptococcus neoformans Is a Eukaryotic Solution to the Problem of Fungal Trans-Cell Wall Transport▿

    PubMed Central

    Rodrigues, Marcio L.; Nimrichter, Leonardo; Oliveira, Débora L.; Frases, Susana; Miranda, Kildare; Zaragoza, Oscar; Alvarez, Mauricio; Nakouzi, Antonio; Feldmesser, Marta; Casadevall, Arturo

    2007-01-01

    The mechanisms by which macromolecules are transported through the cell wall of fungi are not known. A central question in the biology of Cryptococcus neoformans, the causative agent of cryptococcosis, is the mechanism by which capsular polysaccharide synthesized inside the cell is exported to the extracellular environment for capsule assembly and release. We demonstrate that C. neoformans produces extracellular vesicles during in vitro growth and animal infection. Vesicular compartments, which are transferred to the extracellular space by cell wall passage, contain glucuronoxylomannan (GXM), a component of the cryptococcal capsule, and key lipids, such as glucosylceramide and sterols. A correlation between GXM-containing vesicles and capsule expression was observed. The results imply a novel mechanism for the release of the major virulence factor of C. neoformans whereby polysaccharide packaged in lipid vesicles crosses the cell wall and the capsule network to reach the extracellular environment. PMID:17114598

  14. Sweat collection capsule

    NASA Technical Reports Server (NTRS)

    Greenleaf, J. E.; Delaplaine, R. W. (Inventor)

    1980-01-01

    A sweat collection capsule permitting quantitative collection of sweat is described. The device consists of a frame held immobile on the skin, a closure secured to the frame and absorbent material located next to the skin in a cavity formed by the frame and the closure. The absorbent material may be removed from the device by removing the closure from the frame while the frame is held immobile on the skin.

  15. Capsule-train stability

    NASA Astrophysics Data System (ADS)

    Bryngelson, Spencer H.; Freund, Jonathan B.

    2016-07-01

    Elastic capsules flowing in small enough tubes, such as red blood cells in capillaries, are well known to line up into regular single-file trains. The stability of such trains in somewhat wider channels, where this organization is not observed, is studied in a two-dimensional model system that includes full coupling between the viscous flow and suspended capsules. A diverse set of linearly amplifying disturbances, both long-time asymptotic (modal) and transient (nonmodal) perturbations, is identified and analyzed. These have a range of amplification rates and their corresponding forms are wavelike, typically dominated by one of five principal perturbation classes: longitudinal and transverse translations, tilts, and symmetric and asymmetric shape distortions. Finite-amplitude transiently amplifying perturbations are shown to provide a mechanism that can bypass slower asymptotic modal linear growth and precipitate the onset of nonlinear effects. Direct numerical simulations are used to verify the linear analysis and track the subsequent transition of the regular capsule trains into an apparently chaotic flow.

  16. Chemical inhibition of bacterial protein tyrosine phosphatase suppresses capsule production.

    PubMed

    Standish, Alistair J; Salim, Angela A; Zhang, Hua; Capon, Robert J; Morona, Renato

    2012-01-01

    Capsule polysaccharide is a major virulence factor for a wide range of bacterial pathogens, including Streptococcus pneumoniae. The biosynthesis of Wzy-dependent capsules in both gram-negative and -positive bacteria is regulated by a system involving a protein tyrosine phosphatase (PTP) and a protein tyrosine kinase. However, how the system functions is still controversial. In Streptococcus pneumoniae, a major human pathogen, the system is present in all but 2 of the 93 serotypes found to date. In order to study this regulation further, we performed a screen to find inhibitors of the phosphatase, CpsB. This led to the observation that a recently discovered marine sponge metabolite, fascioquinol E, inhibited CpsB phosphatase activity both in vitro and in vivo at concentrations that did not affect the growth of the bacteria. This inhibition resulted in decreased capsule synthesis in D39 and Type 1 S. pneumoniae. Furthermore, concentrations of Fascioquinol E that inhibited capsule also lead to increased attachment of pneumococci to a macrophage cell line, suggesting that this compound would inhibit the virulence of the pathogen. Interestingly, this compound also inhibited the phosphatase activity of the structurally unrelated gram-negative PTP, Wzb, which belongs to separate family of protein tyrosine phosphatases. Furthermore, incubation with Klebsiella pneumoniae, which contains a homologous phosphatase, resulted in decreased capsule synthesis. Taken together, these data provide evidence that PTPs are critical for Wzy-dependent capsule production across a spectrum of bacteria, and as such represents a valuable new molecular target for the development of anti-virulence antibacterials.

  17. POLYSACCHARIDE OF COCCIDIOIDES IMMITIS

    PubMed Central

    Pappagianis, D.; Putman, E. W.; Kobayashi, G. S.

    1961-01-01

    Pappagianis, D. (University of California, Berkeley), E. W. Putman, and G. S. Kobayashi. Polysaccharide of Coccidioides immitis. J. Bacteriol. 82:714–723. 1961.—Soluble polysaccharide from mycelia or culture filtrates of Coccidioides immitis was found to consist mainly of mannose, but also included small quantities of galactose and another reducing sugar. Isolation of the polysaccharide by ethanol precipitation provided accompanying nitrogenous material. There was 3 to 4% nitrogen, present in amino acids, but in a nondialyzable (possibly protein or peptide) form. The average molecular weight of the complex was 31,700. Attempts to separate the nitrogenous and polysaccharide materials by chemical methods or by moving boundary electrophoresis were unsuccessful; ultracentrifugation showed a single peak. Despite these findings, there appeared to be several antigenic species present, as indicated by multiple lines of precipitation in double diffusion and quantitative precipitin tests. In the latter, polysaccharide-containing fractions gave precipitates without measurable carbohydrate, suggesting separability of nitrogenous and polysaccharide components. Images PMID:14483753

  18. Contribution of fucose-containing capsules in Klebsiella pneumoniae to bacterial virulence in mice.

    PubMed

    Wu, June Hsieh; Wu, Albert M; Tsai, Cheng Gie; Chang, Xin-Yu; Tsai, Shih-Feng; Wu, Ting-Shu

    2008-01-01

    Bacterium Klebsiella pneumoniae (KP) contains a prominent capsule. Clinical infections usually are associated with pneumonia or urinary tract infection (UTI). Emerging evidence implicates KP in severe liver abscess especially in diabetic patients. The goal of this study was to investigate the capsular polysaccharides from KP of liver abscess (hepatic-KP) and of UTI-KP. The composition of capsular polysaccharides was analyzed by capillary high-performance liquid chromatography (HPLC, Dionex system). The terminal sugars were assayed by binding ability to lectins. The results showed that the capsule of a hepatic KP (KpL1) from a diabetic patient contained fucose, while the capsule from UTI-KP (KpU1) did not. The absence of fucose was verified by the absence of detectable polymerase chain reaction (PCR) fragment for fucose synthesis genes, gmd and wcaG in KpU1. Mice infected with the KpL1 showed high fatality, whereas those infected with the KpU1 showed high survival rate. The KpL1 capsule was reactive to lectins AAA and AAL, which detect fucose, while the KpU1 capsule was reactive to lectin GNA, which detects mannose. Phagocytosis experiment in mouse peritoneal cavity indicated that the peritoneal macrophages could interact with KpU1, while rare association of KpL1 with macrophages was observed. This study revealed that different polysaccharides were displayed on the bacterial capsules of virulent KpL1 as compared with the less virulent KpU1. Interaction of KpU1 with mice peritoneal macrophages was more prominent than that of KpL1. The possession of fucose might contribute to KpL1 virulence by avoiding phagocytosis since fucose on bacteria had been implicated in immune evasion.

  19. Systematic capsule gene disruption reveals the central role of galactose metabolism on Cryptococcus neoformans virulence.

    PubMed

    Moyrand, Frédérique; Fontaine, Thierry; Janbon, Guilhem

    2007-05-01

    The polysaccharidic capsule is the main virulence factor of Cryptococcus neoformans. It primarily comprised of two polysaccharides: glucuronoxylomannan (GXM, 88% of the capsule mass) and galactoxylomannan (GalXM, 7% of the capsule mass). We constructed a large collection of mutant strains in which genes potentially involved in capsule biosynthesis were deleted. We used a new post-genomic approach to study the virulence of the strains. Primers specific for unique tags associated with the disruption cassette were used in a real-time PCR virulence assay to measure the fungal burden of each strain in different organs of mice in multi-infection experiments. With this very sensitive assay, we identified a putative UDP-glucose epimerase (Uge1p) and a putative UDP-galactose transporter (Ugt1p) essential for C. neoformans virulence. The uge1Delta and ugt1Delta strains are temperature sensitive and do not produce GalXM but synthesize a larger capsule. These mutant strains (GalXM negative, GXM positive) are not able to colonize the brain even at the first day of infection whereas GXM-negative strains (GalXM positive) can still colonize the brain, although less efficiently than the wild-type strain.

  20. Genomic analysis reveals the molecular basis for capsule loss in the group B Streptococcus population.

    PubMed

    Rosini, Roberto; Campisi, Edmondo; De Chiara, Matteo; Tettelin, Hervé; Rinaudo, Daniela; Toniolo, Chiara; Metruccio, Matteo; Guidotti, Silvia; Sørensen, Uffe B Skov; Kilian, Mogens; Ramirez, Mario; Janulczyk, Robert; Donati, Claudio; Grandi, Guido; Margarit, Immaculada

    2015-01-01

    The human and bovine bacterial pathogen Streptococcus agalactiae (Group B Streptococcus, GBS) expresses a thick polysaccharide capsule that constitutes a major virulence factor and vaccine target. GBS can be classified into ten distinct serotypes differing in the chemical composition of their capsular polysaccharide. However, non-typeable strains that do not react with anti-capsular sera are frequently isolated from colonized and infected humans and cattle. To gain a comprehensive insight into the molecular basis for the loss of capsule expression in GBS, a collection of well-characterized non-typeable strains was investigated by genome sequencing. Genome based phylogenetic analysis extended to a wide population of sequenced strains confirmed the recently observed high clonality among GBS lineages mainly containing human strains, and revealed a much higher degree of diversity in the bovine population. Remarkably, non-typeable strains were equally distributed in all lineages. A number of distinct mutations in the cps operon were identified that were apparently responsible for inactivation of capsule synthesis. The most frequent genetic alterations were point mutations leading to stop codons in the cps genes, and the main target was found to be cpsE encoding the portal glycosyl transferase of capsule biosynthesis. Complementation of strains carrying missense mutations in cpsE with a wild-type gene restored capsule expression allowing the identification of amino acid residues essential for enzyme activity.

  1. Wzi is an outer membrane lectin that underpins group 1 capsule assembly in Escherichia coli.

    PubMed

    Bushell, Simon R; Mainprize, Iain L; Wear, Martin A; Lou, Hubing; Whitfield, Chris; Naismith, James H

    2013-05-01

    Many pathogenic bacteria encase themselves in a polysaccharide capsule that provides a barrier to the physical and immunological challenges of the host. The mechanism by which the capsule assembles around the bacterial cell is unknown. Wzi, an integral outer-membrane protein from Escherichia coli, has been implicated in the formation of group 1 capsules. The 2.6 Å resolution structure of Wzi reveals an 18-stranded β-barrel fold with a novel arrangement of long extracellular loops that blocks the extracellular entrance and a helical bundle that plugs the periplasmic end. Mutagenesis shows that specific extracellular loops are required for in vivo capsule assembly. The data show that Wzi binds the K30 carbohydrate polymer and, crucially, that mutants functionally deficient in vivo show no binding to K30 polymer in vitro. We conclude that Wzi is a novel outer-membrane lectin that assists in the formation of the bacterial capsule via direct interaction with capsular polysaccharides.

  2. Genomic Analysis Reveals the Molecular Basis for Capsule Loss in the Group B Streptococcus Population

    PubMed Central

    Rosini, Roberto; Campisi, Edmondo; De Chiara, Matteo; Tettelin, Hervé; Rinaudo, Daniela; Toniolo, Chiara; Metruccio, Matteo; Guidotti, Silvia; Sørensen, Uffe B. Skov; Kilian, Mogens; Ramirez, Mario; Janulczyk, Robert; Donati, Claudio; Grandi, Guido; Margarit, Immaculada

    2015-01-01

    The human and bovine bacterial pathogen Streptococcus agalactiae (Group B Streptococcus, GBS) expresses a thick polysaccharide capsule that constitutes a major virulence factor and vaccine target. GBS can be classified into ten distinct serotypes differing in the chemical composition of their capsular polysaccharide. However, non-typeable strains that do not react with anti-capsular sera are frequently isolated from colonized and infected humans and cattle. To gain a comprehensive insight into the molecular basis for the loss of capsule expression in GBS, a collection of well-characterized non-typeable strains was investigated by genome sequencing. Genome based phylogenetic analysis extended to a wide population of sequenced strains confirmed the recently observed high clonality among GBS lineages mainly containing human strains, and revealed a much higher degree of diversity in the bovine population. Remarkably, non-typeable strains were equally distributed in all lineages. A number of distinct mutations in the cps operon were identified that were apparently responsible for inactivation of capsule synthesis. The most frequent genetic alterations were point mutations leading to stop codons in the cps genes, and the main target was found to be cpsE encoding the portal glycosyl trasferase of capsule biosynthesis. Complementation of strains carrying missense mutations in cpsE with a wild-type gene restored capsule expression allowing the identification of amino acid residues essential for enzyme activity. PMID:25946017

  3. Genomic analysis reveals the molecular basis for capsule loss in the group B Streptococcus population.

    PubMed

    Rosini, Roberto; Campisi, Edmondo; De Chiara, Matteo; Tettelin, Hervé; Rinaudo, Daniela; Toniolo, Chiara; Metruccio, Matteo; Guidotti, Silvia; Sørensen, Uffe B Skov; Kilian, Mogens; Ramirez, Mario; Janulczyk, Robert; Donati, Claudio; Grandi, Guido; Margarit, Immaculada

    2015-01-01

    The human and bovine bacterial pathogen Streptococcus agalactiae (Group B Streptococcus, GBS) expresses a thick polysaccharide capsule that constitutes a major virulence factor and vaccine target. GBS can be classified into ten distinct serotypes differing in the chemical composition of their capsular polysaccharide. However, non-typeable strains that do not react with anti-capsular sera are frequently isolated from colonized and infected humans and cattle. To gain a comprehensive insight into the molecular basis for the loss of capsule expression in GBS, a collection of well-characterized non-typeable strains was investigated by genome sequencing. Genome based phylogenetic analysis extended to a wide population of sequenced strains confirmed the recently observed high clonality among GBS lineages mainly containing human strains, and revealed a much higher degree of diversity in the bovine population. Remarkably, non-typeable strains were equally distributed in all lineages. A number of distinct mutations in the cps operon were identified that were apparently responsible for inactivation of capsule synthesis. The most frequent genetic alterations were point mutations leading to stop codons in the cps genes, and the main target was found to be cpsE encoding the portal glycosyl transferase of capsule biosynthesis. Complementation of strains carrying missense mutations in cpsE with a wild-type gene restored capsule expression allowing the identification of amino acid residues essential for enzyme activity. PMID:25946017

  4. Updated Campylobacter jejuni capsule PCR multiplex typing system and its application to clinical isolates from south and southeast Asia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Campylobacter jejuni produces a polysaccharide capsule that is the major determinant of the Penner serotyping scheme. This passive slide agglutination typing system was developed in the early 1980’s and was recognized for over two decades as gold standard for C. jejuni typing. A preliminary multiple...

  5. Sialylation of Streptococcus suis serotype 2 is essential for capsule expression but is not responsible for the main capsular epitope.

    PubMed

    Lecours, Marie-Pier; Fittipaldi, Nahuel; Takamatsu, Daisuke; Okura, Masatoshi; Segura, Mariela; Goyette-Desjardins, Guillaume; Van Calsteren, Marie-Rose; Gottschalk, Marcelo

    2012-09-01

    The capsular polysaccharide is a critical virulence factor of the swine and zoonotic pathogen Streptococcus suis serotype 2. The capsule of this bacterium is composed of five different sugars, including terminal sialic acid. To evaluate the role of sialic acid in the pathogenesis of the infection, the neuC gene, encoding for an enzyme essential for sialic acid biosynthesis, was inactivated in a highly virulent S. suis serotype 2 strain. Using transmission electron microscopy, it was shown that inactivation of neuC resulted in loss of expression of the whole capsule. Compared to the parent strain, the ΔneuC mutant strain was more phagocytosed by macrophages and was also severely impaired in virulence in a mouse infection model. Both native and desialylated S. suis serotype 2 purified capsular polysaccharides were recognized by a polyclonal anti-whole cell S. suis serotype 2 serum and a monospecific polyclonal anti-capsule serotype 2 serum. In contrast, only the native capsular polysaccharide was recognized by a monoclonal antibody specific for the sialic acid moiety of the serotype 2 capsule. Together, our results infer that sialylation of S. suis serotype 2 may be essential for capsule expression, but that this sugar is not the main epitope of this serotype.

  6. Optimal Design of Capsule Transporting Pipeline carrying Spherical Capsules

    NASA Astrophysics Data System (ADS)

    Asim, Taimoor; Mishra, Rakesh; Ubbi, Kuldip

    2012-05-01

    A capsule pipeline transports material or cargo in capsules propelled by fluid flowing through a pipeline. The cargo may either be contained in capsules (such as wheat enclosed inside sealed cylindrical containers), or may itself be the capsules (such as coal compressed into the shape of a cylinder or sphere). As the concept of capsule transportation is relatively new, the capsule pipelines need to be designed optimally for commercial viability. An optimal design of such a pipeline would have minimum pressure drop due to the presence of the solid medium in the pipeline, which corresponds to minimum head loss and hence minimum pumping power required to drive the capsules and the transporting fluid. The total cost for the manufacturing and maintenance of such pipelines is yet another important variable that needs to be considered for the widespread commercial acceptance of capsule transporting pipelines. To address this, the optimisation technique presented here is based on the least-cost principle. Pressure drop relationships have been incorporated to calculate the pumping requirements for the system. The maintenance and manufacturing costs have been computed separately to analyse their effects on the optimisation process. A design example has been included to show the usage of the model presented. The results indicate that for a specific throughput, there exists an optimum diameter of the pipeline for which the total cost for the piping system is at its minimum.

  7. Intact capture of hypervelocity particles

    NASA Technical Reports Server (NTRS)

    Tsou, P.; Brownlee, D. E.; Albee, A. L.

    1986-01-01

    Knowledge of the phase, structure, and crystallography of cosmic particles, as well as their elemental and isotopic compositions, would be very valuable information toward understanding the nature of our solar system. This information can be obtained from the intact capture of large mineral grains of cosmic particles from hypervelocity impacts. Hypervelocity experiments of intact capture in underdense media have indicated realistic potential in this endeaver. The recovery of the thermal blankets and louvers from the Solar Max spacecraft have independently verified this potential in the unintended capture of cosmic materials from hypervelocity impacts. Passive underdense media will permit relatively simple and inexpensive missions to capture cosmic particles intact, either by going to a planetary body or by waiting for the particles to come to the Shuttle or the Space Station. Experiments to explore the potential of using various underdense media for an intact comet sample capture up to 6.7 km/s were performed at NASA Ames Research Center Vertical Gun Range. Explorative hypervelocity experiments up to 7.9 km/s were also made at the Ernst Mach Institute. These experiments have proven that capturing intact particles at hypervelocity impacts is definitely possible. Further research is being conducted to achieve higher capture ratios at even higher hypervelocities for even smaller projectiles.

  8. Intact capture of hypervelocity particles

    NASA Astrophysics Data System (ADS)

    Tsou, P.; Brownlee, D. E.; Albee, A. L.

    Knowledge of the phase, structure, and crystallography of cosmic particles, as well as their elemental and isotopic compositions, would be very valuable information toward understanding the nature of our solar system. This information can be obtained from the intact capture of large mineral grains of cosmic particles from hypervelocity impacts. Hypervelocity experiments of intact capture in underdense media have indicated realistic potential in this endeaver. The recovery of the thermal blankets and louvers from the Solar Max spacecraft have independently verified this potential in the unintended capture of cosmic materials from hypervelocity impacts. Passive underdense media will permit relatively simple and inexpensive missions to capture cosmic particles intact, either by going to a planetary body or by waiting for the particles to come to the Shuttle or the Space Station. Experiments to explore the potential of using various underdense media for an intact comet sample capture up to 6.7 km/s were performed at NASA Ames Research Center Vertical Gun Range. Explorative hypervelocity experiments up to 7.9 km/s were also made at the Ernst Mach Institute. These experiments have proven that capturing intact particles at hypervelocity impacts is definitely possible. Further research is being conducted to achieve higher capture ratios at even higher hypervelocities for even smaller projectiles.

  9. Magnetism in metal-organic capsules

    SciTech Connect

    Atwood, Jerry L.; Brechin, Euan K; Dalgarno, Scott J.; Inglis, Ross; Jones, Leigh F.; Mossine, Andrew; Paterson, Martin J.; Power, Nicholas P.; Teat, Simon J.

    2010-01-07

    Nickel and cobalt seamed metal-organic capsules have been isolated and studied using structural, magnetic and computational approaches. Antiferromagnetic exchange in the Ni capsule results from coordination environments enforced by the capsule framework.

  10. A role for LHC1 in higher order structure and complement binding of the Cryptococcus neoformans capsule.

    PubMed

    Park, Yoon-Dong; Shin, Soowan; Panepinto, John; Ramos, Jeanie; Qiu, Jin; Frases, Susana; Albuquerque, Patricia; Cordero, Radames J B; Zhang, Nannan; Himmelreich, Uwe; Beenhouwer, David; Bennett, John E; Casadevall, Arturo; Williamson, Peter R

    2014-05-01

    Polysaccharide capsules are important virulence factors for many microbial pathogens including the opportunistic fungus Cryptococcus neoformans. In the present study, we demonstrate an unusual role for a secreted lactonohydrolase of C. neoformans, LHC1 in capsular higher order structure. Analysis of extracted capsular polysaccharide from wild-type and lhc1Δ strains by dynamic and static light scattering suggested a role for the LHC1 locus in altering the capsular polysaccharide, both reducing dimensions and altering its branching, density and solvation. These changes in the capsular structure resulted in LHC1-dependent alterations of antibody binding patterns, reductions in human and mouse complement binding and phagocytosis by the macrophage-like cell line J774, as well as increased virulence in mice. These findings identify a unique molecular mechanism for tertiary structural changes in a microbial capsule, facilitating immune evasion and virulence of a fungal pathogen.

  11. A Role for LHC1 in Higher Order Structure and Complement Binding of the Cryptococcus neoformans Capsule

    PubMed Central

    Park, Yoon-Dong; Shin, Soowan; Panepinto, John; Ramos, Jeanie; Qiu, Jin; Frases, Susana; Albuquerque, Patricia; Cordero, Radames J. B.; Zhang, Nannan; Himmelreich, Uwe; Beenhouwer, David; Bennett, John E.; Casadevall, Arturo; Williamson, Peter R.

    2014-01-01

    Polysaccharide capsules are important virulence factors for many microbial pathogens including the opportunistic fungus Cryptococcus neoformans. In the present study, we demonstrate an unusual role for a secreted lactonohydrolase of C. neoformans, LHC1 in capsular higher order structure. Analysis of extracted capsular polysaccharide from wild-type and lhc1Δ strains by dynamic and static light scattering suggested a role for the LHC1 locus in altering the capsular polysaccharide, both reducing dimensions and altering its branching, density and solvation. These changes in the capsular structure resulted in LHC1-dependent alterations of antibody binding patterns, reductions in human and mouse complement binding and phagocytosis by the macrophage-like cell line J774, as well as increased virulence in mice. These findings identify a unique molecular mechanism for tertiary structural changes in a microbial capsule, facilitating immune evasion and virulence of a fungal pathogen. PMID:24789368

  12. Capsules from pathogenic and non-pathogenic Cryptococcus spp. manifest significant differences in structure and ability to protect against phagocytic cells.

    PubMed

    Araujo, Glauber de S; Fonseca, Fernanda L; Pontes, Bruno; Torres, Andre; Cordero, Radames J B; Zancopé-Oliveira, Rosely M; Casadevall, Arturo; Viana, Nathan B; Nimrichter, Leonardo; Rodrigues, Marcio L; Garcia, Eloi S; Souza, Wanderley de; Frases, Susana

    2012-01-01

    Capsule production is common among bacterial species, but relatively rare in eukaryotic microorganisms. Members of the fungal Cryptococcus genus are known to produce capsules, which are major determinants of virulence in the highly pathogenic species Cryptococcus neoformans and Cryptococcus gattii. Although the lack of virulence of many species of the Cryptococcus genus can be explained solely by the lack of mammalian thermotolerance, it is uncertain whether the capsules from these organisms are comparable to those of the pathogenic cryptococci. In this study, we compared the characteristic of the capsule from the non-pathogenic environmental yeast Cryptococcus liquefaciens with that of C. neoformans. Microscopic observations revealed that C. liquefaciens has a capsule visible in India ink preparations that was also efficiently labeled by three antibodies generated to specific C. neoformans capsular antigens. Capsular polysaccharides of C. liquefaciens were incorporated onto the cell surface of acapsular C. neoformans mutant cells. Polysaccharide composition determinations in combination with confocal microscopy revealed that C. liquefaciens capsule consisted of mannose, xylose, glucose, glucuronic acid, galactose and N-acetylglucosamine. Physical chemical analysis of the C. liquefaciens polysaccharides in comparison with C. neoformans samples revealed significant differences in viscosity, elastic properties and macromolecular structure parameters of polysaccharide solutions such as rigidity, effective diameter, zeta potential and molecular mass, which nevertheless appeared to be characteristics of linear polysaccharides that also comprise capsular polysaccharide of C. neoformans. The environmental yeast, however, showed enhanced susceptibility to the antimicrobial activity of the environmental phagocytes, suggesting that the C. liquefaciens capsular components are insufficient in protecting yeast cells against killing by amoeba. These results suggest that capsular

  13. Capsules from Pathogenic and Non-Pathogenic Cryptococcus spp. Manifest Significant Differences in Structure and Ability to Protect against Phagocytic Cells

    PubMed Central

    Araujo, Glauber de S.; Fonseca, Fernanda L.; Pontes, Bruno; Torres, Andre; Cordero, Radames J. B.; Zancopé-Oliveira, Rosely M.; Casadevall, Arturo; Viana, Nathan B.; Nimrichter, Leonardo; Rodrigues, Marcio L.; Garcia, Eloi S.; de Souza, Wanderley; Frases, Susana

    2012-01-01

    Capsule production is common among bacterial species, but relatively rare in eukaryotic microorganisms. Members of the fungal Cryptococcus genus are known to produce capsules, which are major determinants of virulence in the highly pathogenic species Cryptococcus neoformans and Cryptococcus gattii. Although the lack of virulence of many species of the Cryptococcus genus can be explained solely by the lack of mammalian thermotolerance, it is uncertain whether the capsules from these organisms are comparable to those of the pathogenic cryptococci. In this study, we compared the characteristic of the capsule from the non-pathogenic environmental yeast Cryptococcus liquefaciens with that of C. neoformans. Microscopic observations revealed that C. liquefaciens has a capsule visible in India ink preparations that was also efficiently labeled by three antibodies generated to specific C. neoformans capsular antigens. Capsular polysaccharides of C. liquefaciens were incorporated onto the cell surface of acapsular C. neoformans mutant cells. Polysaccharide composition determinations in combination with confocal microscopy revealed that C. liquefaciens capsule consisted of mannose, xylose, glucose, glucuronic acid, galactose and N-acetylglucosamine. Physical chemical analysis of the C. liquefaciens polysaccharides in comparison with C. neoformans samples revealed significant differences in viscosity, elastic properties and macromolecular structure parameters of polysaccharide solutions such as rigidity, effective diameter, zeta potential and molecular mass, which nevertheless appeared to be characteristics of linear polysaccharides that also comprise capsular polysaccharide of C. neoformans. The environmental yeast, however, showed enhanced susceptibility to the antimicrobial activity of the environmental phagocytes, suggesting that the C. liquefaciens capsular components are insufficient in protecting yeast cells against killing by amoeba. These results suggest that capsular

  14. Capsules from pathogenic and non-pathogenic Cryptococcus spp. manifest significant differences in structure and ability to protect against phagocytic cells.

    PubMed

    Araujo, Glauber de S; Fonseca, Fernanda L; Pontes, Bruno; Torres, Andre; Cordero, Radames J B; Zancopé-Oliveira, Rosely M; Casadevall, Arturo; Viana, Nathan B; Nimrichter, Leonardo; Rodrigues, Marcio L; Garcia, Eloi S; Souza, Wanderley de; Frases, Susana

    2012-01-01

    Capsule production is common among bacterial species, but relatively rare in eukaryotic microorganisms. Members of the fungal Cryptococcus genus are known to produce capsules, which are major determinants of virulence in the highly pathogenic species Cryptococcus neoformans and Cryptococcus gattii. Although the lack of virulence of many species of the Cryptococcus genus can be explained solely by the lack of mammalian thermotolerance, it is uncertain whether the capsules from these organisms are comparable to those of the pathogenic cryptococci. In this study, we compared the characteristic of the capsule from the non-pathogenic environmental yeast Cryptococcus liquefaciens with that of C. neoformans. Microscopic observations revealed that C. liquefaciens has a capsule visible in India ink preparations that was also efficiently labeled by three antibodies generated to specific C. neoformans capsular antigens. Capsular polysaccharides of C. liquefaciens were incorporated onto the cell surface of acapsular C. neoformans mutant cells. Polysaccharide composition determinations in combination with confocal microscopy revealed that C. liquefaciens capsule consisted of mannose, xylose, glucose, glucuronic acid, galactose and N-acetylglucosamine. Physical chemical analysis of the C. liquefaciens polysaccharides in comparison with C. neoformans samples revealed significant differences in viscosity, elastic properties and macromolecular structure parameters of polysaccharide solutions such as rigidity, effective diameter, zeta potential and molecular mass, which nevertheless appeared to be characteristics of linear polysaccharides that also comprise capsular polysaccharide of C. neoformans. The environmental yeast, however, showed enhanced susceptibility to the antimicrobial activity of the environmental phagocytes, suggesting that the C. liquefaciens capsular components are insufficient in protecting yeast cells against killing by amoeba. These results suggest that capsular

  15. Spacecraft Escape Capsule

    NASA Technical Reports Server (NTRS)

    Robertson, Edward A.; Charles, Dingell W.; Bufkin, Ann L.; Rodriggs, Liana M.; Peterson, Wayne; Cuthbert, Peter; Lee, David E.; Westhelle, Carlos

    2006-01-01

    A report discusses the Gumdrop capsule a conceptual spacecraft that would enable the crew to escape safely in the event of a major equipment failure at any time from launch through atmospheric re-entry. The scaleable Gumdrop capsule would comprise a command module (CM), a service module (SM), and a crew escape system (CES). The CM would contain a pressurized crew environment that would include avionic, life-support, thermal control, propulsive attitude control, and recovery systems. The SM would provide the primary propulsion and would also supply electrical power, life-support resources, and active thermal control to the CM. The CES would include a solid rocket motor, embedded within the SM, for pushing the CM away from the SM in the event of a critical thermal-protection-system failure or loss of control. The CM and SM would normally remain integrated with each other from launch through recovery, but could be separated using the CES, if necessary, to enable the safe recovery of the crew in the CM. The crew escape motor could be used, alternatively, as a redundant means of de-orbit propulsion for the CM in the event of a major system failure in the SM.

  16. Intact capture of cosmic dust

    NASA Technical Reports Server (NTRS)

    Tsou, P.

    1991-01-01

    The focus of this development effort is to capture dust particles at hypervelocities intact and unmelted in order to preserve volatile organics. At the same time, the capture process must minimize any organic elemental or compound contamination to prevent any compromise of exobiological analyses. Inorganic silicate aerogel has been developed as a successful capture medium to satisfy both requirements of intact capture and minimal organic contamination. Up to 6 km/s, silicate projectiles from a few microns up to 100 microns have been captured intact without any melting and with minimal loss of mass. Carbon in silicate aerogel can be reduced to less than 1 part in 1000 and hydrogen 3 parts in 1000 when baked in air. Under controlled inert gas environments, additional hydrocarbon reduction can be achieved.

  17. Impulse-driven Micromechanism Capsule

    NASA Astrophysics Data System (ADS)

    Ito, Takahiro; Ishimori, Shohei; Hayashi, Teru

    We have developed a traveling small capsule, which has a smooth outer surface and is driven by inertia force and friction force. Measuring only 7 mm in diameter and 12 mm in length, it is sufficiently small to be placed in the human gullet or intestines. The capsule contains a small magnet and a coil, and an electric pulse drives the magnet to move the capsule. We performed an experimental investigation on making our capsule travel on a plastic material, which has similar elasticity characteristics to the living body. We also showed that it can travel on the surface of a pig's intestine. Our capsule may be useful for medical treatments such as inspection, drug delivery and operation.

  18. Differential activities of bacteriophage depolymerase on bacterial polysaccharide: binding is essential but degradation is inhibitory in phage infection of K1-defective Escherichia coli.

    PubMed Central

    Pelkonen, S; Aalto, J; Finne, J

    1992-01-01

    Host range mutants were derived from bacteriophages PK1A and PK1E specific for the K1 polysialic acid capsule of Escherichia coli. The mutants were selected for their ability to infect E. coli bacteria with a low level of the K1 capsule. A specific loss of the cleaving activity of the phage endosialidase was observed in all the mutants, while the ability to bind specifically to the polysialic acid capsule was retained. The results indicate that the polysaccharide-binding activity of the bacteriophage enzyme is essential for the infection process. The cleaving activity, in contrast, is required for the penetration of the dense polysaccharide of wild-type bacteria but is inhibitory in the infection of bacteria with a sparse capsular polysaccharide. Images PMID:1447142

  19. Role for Golgi reassembly and stacking protein (GRASP) in polysaccharide secretion and fungal virulence

    PubMed Central

    Kmetzsch, Lívia; Joffe, Luna S.; Staats, Charley C.; de Oliveira, Débora L.; Fonseca, Fernanda L.; Cordero, Radames J. B.; Casadevall, Arturo; Nimrichter, Leonardo; Schrank, Augusto; Vainstein, Marilene H.; Rodrigues, Marcio L.

    2011-01-01

    Secretion of virulence factors is a critical mechanism for the establishment of cryptococcosis, a disease caused by the yeast pathogen Cryptococcus neoformans. One key virulence strategy of C. neoformans is the release of glucuronoxylomannan (GXM), a capsule-associated immune-modulatory polysaccharide that reaches the extracellular space through secretory vesicles. Golgi reassembly and stacking protein (GRASP) is required for unconventional protein secretion mechanisms in different eukaryotic cells, but its role in polysaccharide secretion is unknown. This study demonstrates that a C. neoformans functional mutant of a GRASP ortholog had attenuated virulence in an animal model of cryptococcosis, in comparison to wild type (WT) and reconstituted cells. Mutant cells manifested altered Golgi morphology, failed to produce typical polysaccharide capsules and showed a reduced ability to secrete GXM both in vitro and during animal infection. Isolation of GXM from cultures of WT, reconstituted or mutant strains revealed that the GRASP ortholog mutant produced polysaccharides with reduced dimensions. The mutant was also more efficiently associated to and killed by macrophages than WT and reconstituted cells. These results demonstrate that GRASP, a protein involved in unconventional protein secretion, is also required for polysaccharide secretion and virulence in C. neoformans. PMID:21542865

  20. Role for Golgi reassembly and stacking protein (GRASP) in polysaccharide secretion and fungal virulence.

    PubMed

    Kmetzsch, Lívia; Joffe, Luna S; Staats, Charley C; de Oliveira, Débora L; Fonseca, Fernanda L; Cordero, Radames J B; Casadevall, Arturo; Nimrichter, Leonardo; Schrank, Augusto; Vainstein, Marilene H; Rodrigues, Marcio L

    2011-07-01

    Secretion of virulence factors is a critical mechanism for the establishment of cryptococcosis, a disease caused by the yeast pathogen Cryptococcus neoformans. One key virulence strategy of C. neoformans is the release of glucuronoxylomannan (GXM), a capsule-associated immune-modulatory polysaccharide that reaches the extracellular space through secretory vesicles. Golgi reassembly and stacking protein (GRASP) is required for unconventional protein secretion mechanisms in different eukaryotic cells, but its role in polysaccharide secretion is unknown. This study demonstrates that a C. neoformans functional mutant of a GRASP orthologue had attenuated virulence in an animal model of cryptococcosis, in comparison with wild-type (WT) and reconstituted cells. Mutant cells manifested altered Golgi morphology, failed to produce typical polysaccharide capsules and showed a reduced ability to secrete GXM both in vitro and during animal infection. Isolation of GXM from cultures of WT, reconstituted or mutant strains revealed that the GRASP orthologue mutant produced polysaccharides with reduced dimensions. The mutant was also more efficiently associated to and killed by macrophages than WT and reconstituted cells. These results demonstrate that GRASP, a protein involved in unconventional protein secretion, is also required for polysaccharide secretion and virulence in C. neoformans.

  1. Quantitative measurements in capsule endoscopy.

    PubMed

    Keuchel, M; Kurniawan, N; Baltes, P; Bandorski, D; Koulaouzidis, A

    2015-10-01

    This review summarizes several approaches for quantitative measurement in capsule endoscopy. Video capsule endoscopy (VCE) typically provides wireless imaging of small bowel. Currently, a variety of quantitative measurements are implemented in commercially available hardware/software. The majority is proprietary and hence undisclosed algorithms. Measurement of amount of luminal contamination allows calculating scores from whole VCE studies. Other scores express the severity of small bowel lesions in Crohn׳s disease or the degree of villous atrophy in celiac disease. Image processing with numerous algorithms of textural and color feature extraction is further in the research focuses for automated image analysis. These tools aim to select single images with relevant lesions as blood, ulcers, polyps and tumors or to omit images showing only luminal contamination. Analysis of motility pattern, size measurement and determination of capsule localization are additional topics. Non-visual wireless capsules transmitting data acquired with specific sensors from the gastrointestinal (GI) tract are available for clinical routine. This includes pH measurement in the esophagus for the diagnosis of acid gastro-esophageal reflux. A wireless motility capsule provides GI motility analysis on the basis of pH, pressure, and temperature measurement. Electromagnetically tracking of another motility capsule allows visualization of motility. However, measurement of substances by GI capsules is of great interest but still at an early stage of development. PMID:26299419

  2. The sbcDC locus mediates repression of type 5 capsule production as part of the SOS response in Staphylococcus aureus.

    PubMed

    Chen, Zhongyi; Luong, Thanh T; Lee, Chia Y

    2007-10-01

    Most strains of Staphylococcus aureus produce one type of capsular polysaccharide that belongs to either type 5 or type 8. The production of these capsules has been shown to be regulated by various regulators. Here we report that the sbcD and sbcC genes are involved in the repression of type 5 capsule production. Chromosomal deletions in the sbcDC genes resulted in increased capsule promoter activity, capsule gene transcripts, and capsule production. The survival rates of the sbcDC deletion mutant were reduced upon UV irradiation compared to those for the wild-type strain Newman, suggesting that the genes are involved in DNA repair in S. aureus. The two genes were organized as an operon and were expressed very early in the exponential growth phase. A subinhibitory concentration of ciprofloxacin or mitomycin C induced sbcDC transcription but repressed the capsule promoter activity, suggesting that the sbcDC genes and the capsule genes are part of the SOS regulon. By reporter gene fusion and Northern blotting, we found that sbcDC regulated capsule by downregulating arl and mgr. Further genetic studies indicate that sbcDC functions upstream of arl and mgr in capsule regulation. Collectively, our results indicate that sbcDC, upon the SOS response, represses type 5 capsule production through an arl-mgr pathway. To our knowledge, this is the first demonstration that an SbcDC homolog was involved in transcriptional regulation.

  3. Influence of capsule shell composition on the performance indicators of hypromellose capsule in comparison to hard gelatin capsules.

    PubMed

    Al-Tabakha, Moawia M; Arida, Adi Issam; Fahelelbom, Khairi M S; Sadek, Bassem; Saeed, Dima Ahmed; Abu Jarad, Rami A; Jawadi, Jeevani

    2015-01-01

    The purpose of this study was to assess the in vitro performances of "vegetable" capsules in comparison to hard gelatin capsules in terms of shell weight variation, reaction to different humidity conditions, resistance to stress in the absence of moisture, powder leakage, disintegration and dissolution. Two types of capsules made of HPMC produced with (Capsule 2) or without (Capsule 3) a gelling agent and hard gelatin capsules (Capsule 1) were assessed. Shell weight variability was relatively low for all tested capsules shells. Although Capsule 1 had the highest moisture content under different humidity conditions, all capsule types were unable to protect the encapsulated hygroscopic polyvinylpyrrolidone (PVP) powder from surrounding humidity. The initial disintegration for all Capsule 1 occurred within 3 min, but for other types of capsules within 6 min (n = 18). Dissolution of acetaminophen was better when the deionized water (DIW) temperature increased from 32 to 42 °C in case of Capsule 1, but the effect of temperature was not significant for the other types of capsules. Acetaminphen dissolution from Capsule 1 was the fastest (i.e. >90% in 10 min) and independent of the media pH or contents unlike Capsule 2 which was influenced by the pH and dissolution medium contents. It is feasible to use hypromellose capsules shells with or without gelling agent for new lines of pharmaceutical products, however, there is a window for capsule shells manufacturing companies to improve the dissolution of their hypromellose capsules to match the conventional gelatin capsule shells and eventually replace them. PMID:25586554

  4. Influence of capsule shell composition on the performance indicators of hypromellose capsule in comparison to hard gelatin capsules.

    PubMed

    Al-Tabakha, Moawia M; Arida, Adi Issam; Fahelelbom, Khairi M S; Sadek, Bassem; Saeed, Dima Ahmed; Abu Jarad, Rami A; Jawadi, Jeevani

    2015-01-01

    The purpose of this study was to assess the in vitro performances of "vegetable" capsules in comparison to hard gelatin capsules in terms of shell weight variation, reaction to different humidity conditions, resistance to stress in the absence of moisture, powder leakage, disintegration and dissolution. Two types of capsules made of HPMC produced with (Capsule 2) or without (Capsule 3) a gelling agent and hard gelatin capsules (Capsule 1) were assessed. Shell weight variability was relatively low for all tested capsules shells. Although Capsule 1 had the highest moisture content under different humidity conditions, all capsule types were unable to protect the encapsulated hygroscopic polyvinylpyrrolidone (PVP) powder from surrounding humidity. The initial disintegration for all Capsule 1 occurred within 3 min, but for other types of capsules within 6 min (n = 18). Dissolution of acetaminophen was better when the deionized water (DIW) temperature increased from 32 to 42 °C in case of Capsule 1, but the effect of temperature was not significant for the other types of capsules. Acetaminphen dissolution from Capsule 1 was the fastest (i.e. >90% in 10 min) and independent of the media pH or contents unlike Capsule 2 which was influenced by the pH and dissolution medium contents. It is feasible to use hypromellose capsules shells with or without gelling agent for new lines of pharmaceutical products, however, there is a window for capsule shells manufacturing companies to improve the dissolution of their hypromellose capsules to match the conventional gelatin capsule shells and eventually replace them.

  5. Orion Capsule Mockup is Dropped

    NASA Video Gallery

    An Orion capsule mockup is dropped from a plane 25,000 feet above the Arizona desert to test its parachute design. Orion will return to Earth at speeds faster than previous human spacecraft, and wi...

  6. Monitoring Intact Viruses Using Aptamers

    PubMed Central

    Kumar, Penmetcha K. R.

    2016-01-01

    Viral diagnosis and surveillance are necessary steps in containing the spread of viral diseases, and they help in the deployment of appropriate therapeutic interventions. In the past, the commonly employed viral detection methods were either cell-culture or molecule-level assays. Most of these assays are laborious and expensive, require special facilities, and provide a slow diagnosis. To circumvent these limitations, biosensor-based approaches are becoming attractive, especially after the successful commercialization of glucose and other biosensors. In the present article, I have reviewed the current progress using the biosensor approach for detecting intact viruses. At the time of writing this review, three types of bioreceptor surfaces (antibody-, glycan-, and aptamer-based) have been explored on different sensing platforms for detecting intact viruses. Among these bioreceptors, aptamer-based sensors have been increasingly explored for detecting intact viruses using surface plasmon resonance (SPR) and other platforms. Special emphasis is placed on the aptamer-based SPR platform in the present review. PMID:27527230

  7. Monitoring Intact Viruses Using Aptamers.

    PubMed

    Kumar, Penmetcha K R

    2016-01-01

    Viral diagnosis and surveillance are necessary steps in containing the spread of viral diseases, and they help in the deployment of appropriate therapeutic interventions. In the past, the commonly employed viral detection methods were either cell-culture or molecule-level assays. Most of these assays are laborious and expensive, require special facilities, and provide a slow diagnosis. To circumvent these limitations, biosensor-based approaches are becoming attractive, especially after the successful commercialization of glucose and other biosensors. In the present article, I have reviewed the current progress using the biosensor approach for detecting intact viruses. At the time of writing this review, three types of bioreceptor surfaces (antibody-, glycan-, and aptamer-based) have been explored on different sensing platforms for detecting intact viruses. Among these bioreceptors, aptamer-based sensors have been increasingly explored for detecting intact viruses using surface plasmon resonance (SPR) and other platforms. Special emphasis is placed on the aptamer-based SPR platform in the present review. PMID:27527230

  8. BENCAP, LLC: CAPSULE VELOCITY TEST

    SciTech Connect

    Meidinger, Brian

    2005-09-07

    Ben Cap, LLC, has a technology that utilizes bebtonite to plug wells. The bentonite is encapsulated in a cardboard capsule, droped down to the bottom of the well where it is allowed to hydrate, causing the bentonite to expand and plug the well. This method of plugging a well is accepted in some, but not all states. This technology can save a significant amount of money when compared to cementing methods currently used to plug and abandon wells. The test objective was to obtain the terminal velocity of the capsule delivery system as it drops through a column of water in a wellbore. Once the terminal velocity is known, the bentonite swelling action can be timed not to begin swelling until it reaches the bottom of the well bore. The results of the test showed that an average speed of 8.93 plus or minus 0.12 ft/sec was achieved by the capsule as it was falling through a column of water. Plotting the data revealed a very linear function with the capsules achieving terminal velocity shortly after being released. The interference of the capsule impacting the casing was not readily apparent in any of the runs, but a siginal sampling anomaly was present in one run. Because the anomaly was so brief and not present in any of the other runs, no solid conclusions could be drawn. Additional testing would be required to determine the effects of capsules impacting a fluid level that is not at surface.

  9. Deformability-based capsule sorting

    NASA Astrophysics Data System (ADS)

    Le Goff, Anne; Munier, Nadege; Maire, Pauline; Edwards-Levy, Florence; Salsac, Anne-Virginie

    2015-11-01

    Many microfluidic devices have been developed for cancer diagnosis applications, most of which relying on costly antibodies. Since some cancer cells display abnormal mechanical properties, new sorting tools based on mechanical sensing are of particular interest. We present a simple, passive pinched flow microfluidic system for capsule sorting. The device consists of a straight microchannel containing a cylindrical obstacle. Thanks to a flow-focusing module placed at the channel entrance, capsules arrive well-centered in the vicinity of the obstacle. Pure size-sorting can be achieved at low shear rate. When increasing the shear rate, capsules are deformed in the narrow space between the pillar and the wall. The softer the capsule, the more tightly it wraps around the obstacle. After the obstacle, streamlines diverge, allowing for the separation between soft capsules, that follow central streamlines, and stiff capsules, that drift away from the obstacle with a wider angle. This proves that we have developed a flexible multipurpose sorting microsystem based on a simple design.

  10. Language and Williams syndrome: how intact is "intact"?

    PubMed

    Karmiloff-Smith, A; Grant, J; Berthoud, I; Davies, M; Howlin, P; Udwin, O

    1997-04-01

    It has been claimed that Williams syndrome (WS), a rare neurodevelopmental disorder, is characterized by serious cognitive deficits alongside intact language. The syndrome is often used as a prime example of the modularity of an innate faculty for morphosyntactic rules. We challenge this claim and hypothesize that morphosyntax, although surprisingly good given WS level of mental retardation, is by no means intact. We make an initial test of this hypothesis through an analysis of the receptive language of a group of English-speaking WS individuals on a standardized morphosyntactic test. We then present an experimental study of expressive language that examines grammatical gender assignment in French-speaking WS patients. Despite a Verbal Mental Age selected to be higher than the chronological age of the young control group, these people with WS continue even in adulthood to show clear-cut deficits in their production of an aspect of morphosyntax that normal children acquire effortlessly very early. The results of the 2 studies, one focusing on receptive language and the other on expressive language, challenge the notion that comprehension and use of morphosyntactic rules in WS individuals are intact. The Within-domain dissociations regarding the use of grammatical gender assignment across several sentence clements and their difficulties in understanding embedded sentences-two quintessentially linguistic skills-suggest that we must rethink the notion of spared, modular, language capacities in Williams syndrome. We conclude that WS language follows a different path to normal acquisition and may turn out to be more like second language learning. PMID:9180000

  11. Polysaccharides: Occurrence, Significance, and Properties

    NASA Astrophysics Data System (ADS)

    Bemiller, James N.

    Polysaccharides are properties present significance in all living organisms where they carry out one or more of their diverse functions. While there is no specific category or definition of a complex polysaccharide, most are structurally complex. Polysaccharides contain 1-5 different monosaccharide (sugar) units. The different sugar units may have different anomeric configurations and/or be joined by different glycosidic linkages. Polysaccharides may be linear or branched. Branches may be short saccharide units on a linear backbone or the molecule may have a branch-on-branch structure; in either case, the branches may be isolated or clustered. Polysaccharides may contain non-carbohydrate groups. Esters or cyclic acetal groups, when present, can be removed by appropriate treatments. All polysaccharides are polydisperse, i. e., are present in a range of molecular weights rather than having a single molecular weight. Most are polymolecular, i. e., differ in fine structure from molecule to molecule. So most polysaccharides can be said to be structurally complex. They may be attached to protein molecules or to other polysaccharide molecules. They are solvated by water. Most dissolve in aqueous systems, especially if they are alkaline. Polysaccharides can be depolymerized by acids and heat, specific enzymes, and high pH systems following oxidation. Their hydroxyl groups can be esterified (acylated), etherified (alkylated), and oxidized. Amino groups can be acylated (and deacylated). Carboxyl groups can be converted into esters, amides, and amines. Structural modification makes the molecules even more complex and polymolecular and, perhaps, polydisperse.

  12. Optimisation of a Horizontal Capsule Transporting Pipeline carrying Cylindrical Capsules

    NASA Astrophysics Data System (ADS)

    Asim, Taimoor; Mishra, Rakesh; Kollar, Laszlo; Ubbi, Kuldip

    2012-05-01

    Pipelines carrying fluids and slurries are quite common. The third-generation pipelines carrying spherical or cylindrical capsules (hollow containers) filled with minerals or other materials including hazardous liquids are rather a new concept. These pipelines need to be designed optimally for commercial viability. An optimal design of such a pipeline results in minimum pressure drop in the pipeline. This corresponds to minimum head loss and hence minimum pumping power required to drive the capsules and the transporting fluid. This study uses a rigorous approach to predict pumping cost based on Computational Fluid Dynamics (CFD) and hence optimize the design of the capsule transporting pipelines. Pressure drop relationship developed has been incorporated to calculate the pumping requirements for the system. Based on the least-cost principle, a methodology has been developed for the determination of the optimal diameter of cylindrical capsule carrying hydraulic pipeline. This procedure can be applied to obtain the optimal size of the capsule pipeline for minimum pumping and capital costs.

  13. Summary Report for Capsule Dry Storage Project

    SciTech Connect

    JOSEPHSON, W S

    2003-09-04

    There are 1.936 cesium (Cs) and strontium (Sr) capsules stored in pools at the Waste Encapsulation and Storage Facility (WESF). These capsules will be moved to dry storage on the Hanford Site as an interim measure to reduce risk. The Cs/Sr Capsule Dry Storage Project (CDSP) is conducted under the assumption the capsules will eventually be moved to the repository at Yucca Mountain, and the design criteria include requirements that will facilitate acceptance at the repository. The storage system must also permit retrieval of capsules in the event vitrification of the capsule contents is pursued. A cut away drawing of a typical cesium chloride (CsCI) capsule and the capsule property and geometry information are provided in Figure 1.1. Strontium fluoride (SrF{sub 2}) capsules are similar in design to CsCl capsules. Further details of capsule design, current state, and reference information are given later in this report and its references. Capsule production and life history is covered in WMP-16938, Capsule Characterization Report for Capsule Dry Storage Project, and is briefly summarized in Section 5.2 of this report.

  14. Structural characteristics of polysaccharides that induce protection against intra-abdominal abscess formation.

    PubMed Central

    Tzianabos, A O; Onderdonk, A B; Zaleznik, D F; Smith, R S; Kasper, D L

    1994-01-01

    Bacteroides fragilis is the anaerobe most commonly isolated from clinical cases of intra-abdominal sepsis. In a rodent model of this disease process, intraperitoneal injection of the capsular polysaccharide complex (CPC) from B. fragilis provokes abscess formation, while subcutaneous administration of this complex confers protection against B. fragilis-induced intra-abdominal abscesses. The CPC consists of two discrete polysaccharides, polysaccharides A and B (PS A and PS B), each possessing oppositely charged structural groups critical to the ability of these carbohydrates to induce the formation of abscesses. Other bacterial polysaccharides that possess oppositely charged groups (such as the group antigen or capsular polysaccharide from Streptococcus pneumoniae type 1 strains) also exhibited potent abscess-inducing capabilities. We report here that positively and negatively charged groups on polysaccharides are also essential for inducing protection against abscess formation. Vaccination of rats with B. fragilis PS A, PS B, or the S. pneumoniae type 1 capsule protected against intra-abdominal abscesses subsequent to intraperitoneal challenge with each of these polysaccharides. Chemical conversion of the free amino or carboxyl groups on PS A to uncharged N-acetyl or hydroxymethyl groups, respectively, abrogated the ability of this polymer to confer protection against polysaccharide-mediated abscess formation. Adoptive transfer of splenic T cells from polysaccharide-vaccinated rats to naive animals demonstrated that T cells mediated this protective activity. T cells transferred from animals vaccinated with a polysaccharide repeating unit (Salmonella typhi Vi antigen) that normally contains one carboxyl group but was chemically converted to a polymer that possesses both free amino and carboxyl groups (accomplished by de-N-acetylating the Vi antigen) protected naive T-cell recipients against polysaccharide-induced abscesses. These results demonstrate that a distinct

  15. The core promoter of the capsule operon of Streptococcus pneumoniae is necessary for colonization and invasive disease.

    PubMed

    Shainheit, Mara G; Mulé, Matthew; Camilli, Andrew

    2014-02-01

    Streptococcus pneumoniae is a commensal of the human nasopharynx but can cause invasive diseases, including otitis media, pneumonia, sepsis, and meningitis. The capsular polysaccharide (capsule) is a critical virulence factor required for both asymptomatic colonization and invasive disease, yet the expression level is different in each anatomical site. During colonization, reduced levels of capsule promote binding to the host epithelium and biofilm formation, while during systemic infection, increased capsule is required to evade opsonophagocytosis. How this regulation of capsule expression occurs is incompletely understood. To investigate the contribution of transcriptional regulation on capsule level in the serotype 4 strain TIGR4, we constructed two mutants harboring a constitutive promoter that was either comparably weaker (Pcat) or stronger (PtRNAGlu) than the wild-type (WT) capsule promoter, Pcps. Mild reductions in cpsA and cpsE transcript levels in the Pcat promoter mutant resulted in a 2-fold reduction in total amounts of capsule and in avirulence in murine models of lung and blood infection. Additionally, the PtRNAGlu mutant revealed that, despite expressing enhanced levels of cpsA and cpsE and possessing levels of capsule comparable to those of WT TIGR4, it was still significantly attenuated in all tested in vivo niches. Further analysis using chimeric promoter mutants revealed that the WT -10 and -35 boxes are required for optimal nasopharyngeal colonization and virulence. These data support the hypothesis that dynamic transcriptional regulation of the capsule operon is required and that the core promoter region plays a central role in fine-tuning levels of capsule to promote colonization and invasive disease.

  16. Streptococcus pneumoniae phosphotyrosine phosphatase CpsB and alterations in capsule production resulting from changes in oxygen availability.

    PubMed

    Geno, K Aaron; Hauser, Jocelyn R; Gupta, Kanupriya; Yother, Janet

    2014-06-01

    Streptococcus pneumoniae produces a protective capsular polysaccharide whose production must be modulated for bacterial survival within various host niches. Capsule production is affected in part by a phosphoregulatory system comprised of CpsB, CpsC, and CpsD. Here, we found that growth of serotype 2 strain D39 under conditions of increased oxygen availability resulted in decreased capsule levels concurrent with an ∼5-fold increase in Cps2B-mediated phosphatase activity. The change in Cps2B phosphatase activity did not result from alterations in the levels of either the cps2B transcript or the Cps2B protein. Recombinant Cps2B expressed in Escherichia coli similarly exhibited increased phosphatase activity under conditions of high-oxygen growth. S. pneumoniae D39 derivatives with defined deletion or point mutations in cps2B demonstrated reduced phosphatase activity with corresponding increases in levels of Cps2D tyrosine phosphorylation. There was, however, no correlation between these phenotypes and the level of capsule production. During growth under reduced-oxygen conditions, the Cps2B protein was essential for parental levels of capsule, but phosphatase activity alone could be eliminated without an effect on capsule. Under increased-oxygen conditions, deletion of cps2B did not affect capsule levels. These results indicate that neither Cps2B phosphatase activity nor Cps2D phosphorylation levels per se are determinants of capsule levels, whereas the Cps2B protein is important for capsule production during growth under conditions of reduced but not enhanced oxygen availability. Roles for factors outside the capsule locus, possible interactions between capsule regulatory proteins, and links to other cellular processes are also suggested by the results described in this study.

  17. Analysis of the enzymatic cleavage (beta elimination) of the capsular K5 polysaccharide of Escherichia coli by the K5-specific coliphage: reexamination.

    PubMed Central

    Hänfling, P; Shashkov, A S; Jann, B; Jann, K

    1996-01-01

    The capsular K5 polysaccharide of Escherichia coli is the receptor of the capsule-specific coliphage K5, which harbors an enzyme that degrades the capsular K5 polysaccharide to a number of oligosaccharides. Analysis of the degradation products using gel permeation chromatography, the periodate-thiobarbituric acid and bicinchoninic acid reactions, and nuclear magnetic resonance spectroscopy showed that the major reaction products are hexa-, octa-, and decasaccharides with 4,5-unsaturated glucuronic acid (delta4,5GlcA) at their nonreducing end. Thus, the bacteriophage enzyme is a K5 polysaccharide lyase and not, as we had reported previously, an endo-N-acetylglucosaminidase. PMID:8755913

  18. Iodine-Catalyzed Polysaccharide Esterification

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A review is provided of the recent reports to use iodine-catalyzed esterification reaction to produce esters from polysaccharides. The process entails reaction of the polysaccharide with an acid anhydride in the presence of a catalytic level of iodine, and in the absence of additional solvents. T...

  19. Cations modulate polysaccharide structure to determine FGF-FGFR signaling: a comparison of signaling and inhibitory polysaccharide interactions with FGF-1 in solution.

    PubMed

    Guimond, Scott E; Rudd, Timothy R; Skidmore, Mark A; Ori, Alessandro; Gaudesi, Davide; Cosentino, Cesare; Guerrini, Marco; Edge, Ruth; Collison, David; McInnes, Eric; Torri, Giangiacomo; Turnbull, Jeremy E; Fernig, David G; Yates, Edwin A

    2009-06-01

    For heparan sulfate (HS) to bind and regulate the activity of proteins, the polysaccharide must present an appropriate sequence and adopt a suitable conformation. The conformations of heparin derivatives, as models of HS, are altered via a change in the associated cations, and this can drastically modify their FGF signaling activities. Here, we report that changing the cations associated with an N-acetyl-enriched heparin polysaccharide, from sodium to copper(II), converted it from supporting signaling through the fibroblast growth factor receptor (FGF-1-FGFR1c) tyrosine kinase signaling system to being inhibitory in a cell-based BaF3 assay. Nuclear magnetic resonance and synchrotron radiation circular dichroism (SRCD) spectroscopy demonstrated that the polysaccharide conformation differed in the presence of sodium or copper(II) cations. Electron paramagnetic resonance confirmed the environment of the copper(II) ion on the N-acetyl-enriched polysaccharide was distinct from that previously observed with intact heparin, which supported signaling. Secondary structures in solution complexes of polysaccharides with FGF-1 (which either supported signaling through FGFR1c or were inhibitory) were determined by SRCD. This allowed direct comparison of the two FGF-1-polysaccharide complexes in solution, containing identical molecular components and differing only in their cation content. Subtle structural differences were revealed, including a reduction in the level of disordered structure in the inhibitory complex. PMID:19400583

  20. Synthesis and characterization of Escherichia coli O18 O-polysaccharide conjugate vaccines.

    PubMed Central

    Cryz, S J; Cross, A S; Sadoff, J C; Fürer, E

    1990-01-01

    Nontoxic, serologically reactive O polysaccharide was derived from Escherichia coli O18 lipopolysaccharide by acid hydrolysis, extraction with organic solvents, and gel filtration chromatography. Oxidized O polysaccharide was covalently coupled to either Pseudomonas aeruginosa toxin A or cholera toxin by using adipic acid dihydrazide as a spacer molecule in the presence of carbodiimide. The resulting conjugates were composed of approximately equal amounts of O polysaccharide and protein and were nontoxic and nonpyrogenic. Both conjugates engendered an immunoglobulin G antibody response in rabbits that recognized native O18 lipopolysaccharide. Such antibody was able to promote the uptake and killing of an E. coli O18 strain bearing the K1 capsule by human polymorphonuclear leukocytes. Immunoglobulin G isolated from the sera of rabbits immunized with either conjugate afforded protection against an E. coli O18 challenge when passively transferred to mice. PMID:2105272

  1. Polysaccharides of the red algae.

    PubMed

    Usov, Anatolii I

    2011-01-01

    Red algae (Rhodophyta) are known as the source of unique sulfated galactans, such as agar, agarose, and carrageenans. The wide practical uses of these polysaccharides are based on their ability to form strong gels in aqueous solutions. Gelling polysaccharides usually have molecules built up of repeating disaccharide units with a regular distribution of sulfate groups, but most of the red algal species contain more complex galactans devoid of gelling ability because of various deviations from the regular structure. Moreover, several red algae may contain sulfated mannans or neutral xylans instead of sulfated galactans as the main structural polysaccharides. This chapter is devoted to a description of the structural diversity of polysaccharides found in the red algae, with special emphasis on the methods of structural analysis of sulfated galactans. In addition to the structural information, some data on the possible use of red algal polysaccharides as biologically active polymers or as taxonomic markers are briefly discussed.

  2. Adhesive capsulitis: a case report

    PubMed Central

    Kazemi, Mohsen

    2000-01-01

    Adhesive capsulitis or frozen shoulder is an uncommon entity in athletes. However, it is a common cause of shoulder pain and disability in the general population. Although it is a self limiting ailment, its rather long, restrictive and painful course forces the affected person to seek treatment. Conservative management remains the mainstay treatment of adhesive capsulitis. This includes chiropractic manipulation of the shoulder, therapeutic modalities, mobilization, exercise, soft tissue therapy, nonsteroidal anti-inflammatory drugs, and steroid injections. Manipulation under anesthesia is advocated when the conservative treatment fails. A case of secondary adhesive capsulitis in a forty-seven-year-old female recreational squash player is presented to illustrate clinical presentation, diagnosis, radiographic assessment and conservative chiropractic management. The patient’s shoulder range of motion was full and pain free with four months of conservative chiropractic care. ImagesFigure 1Figure 2Figure 3

  3. Identification of specific recognition molecules on murine mononuclear phagocytes and B lymphocytes for Vi capsular polysaccharide: modulation of MHC class II expression on stimulation with the polysaccharide.

    PubMed Central

    Qadri, A

    1997-01-01

    Vi bacterial polysaccharide is a homopolymer of alpha 1-4 N-acetyl polygalacturonic acid with variable O-acetylation at position C-3 and forms a capsule around many bacteria. It has been referred to as the virulence factor of Salmonella typhi and is also a candidate vaccine against typhoid fever. The present study reports the interaction of this polysaccharide with murine mononuclear phagocytes and lymphocytes, and with human monocytes. Vi showed a dose-dependent binding to the murine monocyte cell lines WEHI-274.1 and J774. This binding was abrogated if the polysaccharide was deacetylated, suggesting involvement of acetyl groups in this interaction. Vi also bound to the murine B-cell lymphoma line A20, to peritoneal exudate cells and to a lesser degree to spleen cells and thymocytes from BALB/c mice. The polysaccharide also interacted with the human histiocytic lymphoma line U937 but not with the human monocyte cell line THP-1. Stimulation with Vi led to up-regulation of surface major histocompatibility complex (MHC) class II expression on A20 cells. Immunoprecipitation of Vi-bound molecules from cell surface biotinylated A20 and WEHI-274.1 revealed two bands with MW of about 32,000 and 36,000. The study demonstrates that Vi capsular polysaccharide can interact with mononuclear phagocytes and lymphocytes through specific cell surface molecules and modulate MHC class II expression. Images Figure 5 PMID:9370937

  4. Unveiling Protein Kinase A Targets in Cryptococcus neoformans Capsule Formation.

    PubMed

    Alspaugh, J Andrew

    2016-01-01

    The protein kinase A (PKA) signal transduction pathway has been associated with pathogenesis in many fungal species. Geddes and colleagues [mBio 7(1):e01862-15, 2016, doi:10.1128/mBio.01862-15] used quantitative proteomics approaches to define proteins with altered abundance during protein kinase A (PKA) activation and repression in the opportunistic human fungal pathogen Cryptococcus neoformans. They observed an association between microbial PKA signaling and ubiquitin-proteasome regulation of protein homeostasis. Additionally, they correlated these processes with expression of polysaccharide capsule on the fungal cell surface, the main virulence-associated phenotype in this organism. Not only are their findings important for microbial pathogenesis, but they also support similar associations between human PKA signaling and ubiquitinated protein accumulation in neurodegenerative diseases. PMID:26861014

  5. Unveiling Protein Kinase A Targets in Cryptococcus neoformans Capsule Formation

    PubMed Central

    2016-01-01

    ABSTRACT The protein kinase A (PKA) signal transduction pathway has been associated with pathogenesis in many fungal species. Geddes and colleagues [mBio 7(1):e01862-15, 2016, doi:10.1128/mBio.01862-15] used quantitative proteomics approaches to define proteins with altered abundance during protein kinase A (PKA) activation and repression in the opportunistic human fungal pathogen Cryptococcus neoformans. They observed an association between microbial PKA signaling and ubiquitin-proteasome regulation of protein homeostasis. Additionally, they correlated these processes with expression of polysaccharide capsule on the fungal cell surface, the main virulence-associated phenotype in this organism. Not only are their findings important for microbial pathogenesis, but they also support similar associations between human PKA signaling and ubiquitinated protein accumulation in neurodegenerative diseases. PMID:26861014

  6. Supercooling Water in Cylindrical Capsules

    NASA Astrophysics Data System (ADS)

    Guzman, J. J. Milón; Braga, S. L.

    2005-11-01

    An experimental apparatus was developed to investigate the supercooling phenomenon of water inside cylindrical capsules used for a cold storage process. The coolant is a water-alcohol mixture controlled by a constant temperature bath (CTB). Temperatures varying with time are measured inside and outside the capsule. Cylinders with an internal diameter and thickness of 45 and 1.5 mm, respectively, were made from four different materials: acrylic, PVC, brass, and aluminum. The supercooling period of the water and the nucleation temperature were investigated for different coolant temperatures. The supercooling and nucleation probabilities are shown as a function of the coolant temperature for the four different materials.

  7. Triggered Release from Polymer Capsules

    SciTech Connect

    Esser-Kahn, Aaron P.; Odom, Susan A.; Sottos, Nancy R.; White, Scott R.; Moore, Jeffrey S.

    2011-07-06

    Stimuli-responsive capsules are of interest in drug delivery, fragrance release, food preservation, and self-healing materials. Many methods are used to trigger the release of encapsulated contents. Here we highlight mechanisms for the controlled release of encapsulated cargo that utilize chemical reactions occurring in solid polymeric shell walls. Triggering mechanisms responsible for covalent bond cleavage that result in the release of capsule contents include chemical, biological, light, thermal, magnetic, and electrical stimuli. We present methods for encapsulation and release, triggering methods, and mechanisms and conclude with our opinions on interesting obstacles for chemically induced activation with relevance for controlled release.

  8. Polysaccharides and bacterial plugging

    SciTech Connect

    Fogler, H.S.

    1991-11-01

    Before any successful application of Microbial Enhanced Oil Recovery process can be realized, an understanding of the cells' transport and retentive mechanisms in porous media is needed. Cell transport differs from particle transport in their ability to produce polysaccharides, which are used by cells to adhere to surfaces. Cell injection experiments have been conducted using Leuconostoc cells to illustrate the importance of cellular polysaccharide production as a transport mechanism that hinders cell movement and plugs porous media. Kinetic studies of the Leuconostoc cells, carried out to further understand the plugging rates of porous media, have shown that the cells' growth rates are approximately equal when provided with monosaccharide (glucose and fructose) or sucrose. The only difference in cell metabolism is the production of dextran when sucrose is supplied as a carbon source. Experimentally it has also been shown that the cells' growth rate is weakly dependent upon the sucrose concentration in the media, and strongly dependent upon the concentration of yeast extract. The synthesis of cellular dextran has been found to lag behind cell generation, thus indicating that the cells need to reach maturity before they are capable of expressing the detransucrase enzyme and synthesizing insoluble dextran. Dextran yields were found to be dependent upon the sucrose concentration in the media. 10 refs., 9 figs., 9 tabs.

  9. The molecular basis of polysaccharide cleavage by lytic polysaccharide monooxygenases

    PubMed Central

    Frandsen, Kristian E. H.; Simmons, Thomas J.; Dupree, Paul; Poulsen, Jens-Christian N.; Hemsworth, Glyn R.; Ciano, Luisa; Johnston, Esther M.; Tovborg, Morten; Johansen, Katja S.; von Freiesleben, Pernille; Marmuse, Laurence; Fort, Sébastien; Cottaz, Sylvain; Driguez, Hugues; Henrissat, Bernard; Lenfant, Nicolas; Tuna, Floriana; Baldansuren, Amgalanbaatar; Davies, Gideon J.; Leggio, Leila Lo; Walton, Paul H.

    2016-01-01

    Lytic polysaccharide monooxygenases (LPMOs) are copper-containing enzymes which oxidatively break down recalcitrant polysaccharides such as cellulose and chitin. Since their discovery LPMOs have become integral factors in the industrial utilization of biomass, especially in the sustainable generation of cellulosic bioethanol. We report here the first structural determination of an LPMO–oligosaccharide complex, yielding detailed insights into the mechanism of action of these enzymes. Using a combination of structure and electron paramagnetic resonance spectroscopy, we reveal the means by which LPMOs interact with saccharide substrates. We further uncover electronic and structural features of the enzyme active site, showing how LPMOs orchestrate the reaction of oxygen with polysaccharide chains. PMID:26928935

  10. The molecular basis of polysaccharide cleavage by lytic polysaccharide monooxygenases.

    PubMed

    Frandsen, Kristian E H; Simmons, Thomas J; Dupree, Paul; Poulsen, Jens-Christian N; Hemsworth, Glyn R; Ciano, Luisa; Johnston, Esther M; Tovborg, Morten; Johansen, Katja S; von Freiesleben, Pernille; Marmuse, Laurence; Fort, Sébastien; Cottaz, Sylvain; Driguez, Hugues; Henrissat, Bernard; Lenfant, Nicolas; Tuna, Floriana; Baldansuren, Amgalanbaatar; Davies, Gideon J; Lo Leggio, Leila; Walton, Paul H

    2016-04-01

    Lytic polysaccharide monooxygenases (LPMOs) are copper-containing enzymes that oxidatively break down recalcitrant polysaccharides such as cellulose and chitin. Since their discovery, LPMOs have become integral factors in the industrial utilization of biomass, especially in the sustainable generation of cellulosic bioethanol. We report here a structural determination of an LPMO-oligosaccharide complex, yielding detailed insights into the mechanism of action of these enzymes. Using a combination of structure and electron paramagnetic resonance spectroscopy, we reveal the means by which LPMOs interact with saccharide substrates. We further uncover electronic and structural features of the enzyme active site, showing how LPMOs orchestrate the reaction of oxygen with polysaccharide chains.

  11. Sensor capsule for diagnosis of gastric disorders

    NASA Technical Reports Server (NTRS)

    Holen, J. T.

    1972-01-01

    Motility and pH sensor capsule is developed to monitor gastric acidity, pressure, and temperature. Capsule does not interfere with digestion. Sensor is capsule which includes pH electrode, Pitran pressure transducer, and thermistor temperature sensor all potted in epoxy and enclosed in high density polyethylene sheath.

  12. Mediating chemical reactions using polysaccharides

    NASA Astrophysics Data System (ADS)

    Tyler, Lauren E.

    We have studied the NaBH4-mediated hydrogenation of select alkenes catalyzed by polysaccharide-stabilized nanoparticles. We compared the catalytic properties of Ni-based nanoparticles or Au/Co-based nanoparticles on the hydrogenation of cinnamic acid, cinnamide, cinnamyl alcohol, and ethyl cinnamate. We evaluated the possibility that the type of stabilizing polysaccharide surrounding the nanoparticle may affect the selectivity towards the alkene compounds that undergo the hydrogenation reaction. We found that the hydrogenation of cinnamide or ethyl cinnamate proceeded readily to 100% completion independent of the type of polysaccharide stabilizing the nanoparticle. However, the extent of the hydrogenation of cinnamyl alcohol and cinnamic acid varied greatly depending on the type of polysaccharide stabilizing the nanoparticle. In the course of these studies, we observed that some polysaccharides by themselves promoted the hydrolysis of ethyl cinnamate. Thus, we have raised the hypothesis that some polysaccharides may act as "esterases" and explored the interaction between select polysaccharides and a variety of ester compounds.

  13. An unusual organelle in Cryptococcus neoformans links luminal pH and capsule biosynthesis.

    PubMed

    Yoneda, Aki; Doering, Tamara L

    2009-09-01

    Cryptococcus neoformans is a basidiomycete that causes deadly infections in the immunocompromised. We previously generated a secretion mutant in this fungus by introducing a mutation in the SAV1 gene, which encodes a homolog of the Sec4/Rab8 subfamily GTPases. Under restrictive conditions there are two notable morphological changes in the sav1 mutant: accumulation of post-Golgi vesicles and the appearance of an unusual organelle, which we term the sav1 body (SB). The SB is an electron-transparent structure 0.2-1microm in diameter, with vesicles or other membranous structures associated with the perimeter. Surprisingly, the SB was heavily labeled with anti-glucuronoxylomannan (GXM) antibodies, suggesting that it contains a secreted capsule component, GXM. A structure similar to the SB, also labeled by anti-GXM antibodies, was induced in wild type cells treated with the vacuolar-ATPase inhibitor, bafilomycin A(1). Bafilomycin A(1) and other agents that increase intraluminal pH also inhibited capsule polysaccharide shedding and capsule growth. These studies highlight an unusual organelle observed in C. neoformans with a potential role in polysaccharide synthesis, and a link between luminal pH and GXM biosynthesis.

  14. Mentoring. Information Capsule. Volume 0603

    ERIC Educational Resources Information Center

    Blazer, Christie

    2006-01-01

    Mentoring is a structured one-on-one relationship between an adult and youth that focuses on the needs of the youth, providing him or her with support, guidance, and assistance. This information capsule summarizes research findings on the impact of mentoring on factors such as academic achievement, social behaviors, attitudes, drug and alcohol…

  15. Osmotic buckling of spherical capsules.

    PubMed

    Knoche, Sebastian; Kierfeld, Jan

    2014-11-01

    We study the buckling of elastic spherical shells under osmotic pressure with the osmolyte concentration of the exterior solution as a control parameter. We compare our results for the bifurcation behavior with results for buckling under mechanical pressure control, that is, with an empty capsule interior. We find striking differences for the buckling states between osmotic and mechanical buckling. Mechanical pressure control always leads to fully collapsed states with opposite sides in contact, whereas uncollapsed states with a single finite dimple are generic for osmotic pressure control. For sufficiently large interior osmolyte concentrations, osmotic pressure control is qualitatively similar to buckling under volume control with the volume prescribed by the osmolyte concentrations inside and outside the shell. We present a quantitative theory which also captures the influence of shell elasticity on the relationship between osmotic pressure and volume. These findings are relevant for the control of buckled shapes in applications. We show how the osmolyte concentration can be used to control the volume of buckled shells. An accurate analytical formula is derived for the relationship between the osmotic pressure, the elastic moduli and the volume of buckled capsules. This also allows use of elastic capsules as osmotic pressure sensors or deduction of elastic properties and the internal osmolyte concentration from shape changes in response to osmotic pressure changes. We apply our findings to published experimental data on polyelectrolyte capsules. PMID:25209240

  16. The arl locus positively regulates Staphylococcus aureus type 5 capsule via an mgrA-dependent pathway.

    PubMed

    Luong, Thanh T; Lee, Chia Y

    2006-10-01

    Most clinical Staphylococcus aureus strains produce either type 5 or type 8 capsular polysaccharides. The production of these capsules is influenced by various environmental factors. To study the regulation of capsule, Tn551 transposon mutagenesis and transcriptional reporter gene fusion were employed to identify several putative regulatory loci that influenced capsule gene expression. One of these, the arl locus, was chosen for further analysis. Tn551 was found to insert within the coding region (near the translational start site of the arlR gene). ArlR, along with ArlS, forms a two-component system that has been previously shown to affect autolysis and production of several secreted proteins. Phenotypic analyses of the arlR-specific mutant and gene fusion analyses showed that arlR activated capsule production at the transcriptional level. However, gel mobility shift assays did not support activation of the capsule genes by direct ArlR binding to the primary cap5 promoter region upstream of the operon. In contrast, it was found that arl activated mgrA, an activator for capsule production, whereas mgrA did not have a significant effect on arlR. Genetic studies supported the notion that arlR functions upstream of mgrA with respect to the regulation of capsule production, although gene fusion studies indicated that arl could also regulate capsule independently from mgrA. Collectively, the results suggest that arl positively regulates capsule production at the transcriptional level primarily through an mgrA-dependent pathway.

  17. Capsule loss or death: the position of mutations among capsule genes sways the destiny of Streptococcus suis.

    PubMed

    Lakkitjaroen, Nattakan; Takamatsu, Daisuke; Okura, Masatoshi; Sato, Masumi; Osaki, Makoto; Sekizaki, Tsutomu

    2014-05-01

    Streptococcus suis, an emerging zoonotic pathogen, is responsible for various diseases in swine and humans. Most S. suis strains from clinical cases possess a group of capsular polysaccharide synthesis (cps) genes and phenotypically express capsular polysaccharides (CPs). Although CPs are considered to be an important virulence factor, our previous study showed that many S. suis isolates from porcine endocarditis lost their CPs, and some of these unencapsulated isolates had large insertions or deletions in the cps gene clusters. We further investigated 25 endocarditis isolates with no obvious genetic alterations to elucidate the unencapsulation mechanisms and found that a single-nucleotide substitution and frameshift mutation in two glycosyltransferase genes (cps2E and cps2F) were the main causes of the capsule loss. Moreover, mutations in the genes involved in side-chain formation (cps2J and cps2N), polymerase (cps2I), and flippase (cps2O) appeared to be lethal; however, these lethal effects were relieved by mutations in the cps2EF region. As unencapsulation and even the death of individual cells have recently been suggested to be beneficial to the pathogenesis of infections, the results of the present study provide a further insight into understanding the biological significance of cps mutations during the course of S. suis infections.

  18. Prolactin is associated with the development of photorefractoriness in intact, castrated, and testosterone-implanted starlings

    SciTech Connect

    Goldsmith, A.R.; Nicholls, T.J.

    1984-05-01

    Using radioimmunoassays, prolactin, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) were measured in the plasma of intact, castrated, and testosterone-implanted male starlings. Two groups of birds (intact and castrated males) were transferred when photosensitive from short (8-hr) to long (16-hr) day lengths; in both cases plasma prolactin levels increased steadily reaching a peak after 5 weeks of photostimulation, at the time of the onset of photorefractoriness. Three groups (intacts, castrates, and castrates implanted with Silastic capsules containing testosterone) were exposed to day lengths increasing by 30 min per week from 8 to 16 hr. Again, prolactin levels increased in a similar fashion in all three groups at the time of refractoriness, which occurred when the day length reached 15-16 hr. Thus the timing of photorefractoriness and the associated rise in prolactin secretion which occur in response to photostimulation do not depend upon the presence of the gonads and are not affected when testosterone is maintained at a constant high level. Nor is the increase in prolactin altered when the cycle of gonadotrophin secretion which normally precedes it is completely suppressed by the implantation of a testosterone capsule. It would seem that prolactin secretion in the starling is stimulated by transfer from short to long day lengths, but not as a consequence of high gonadotrophin or androgen secretion rates.

  19. High-throughput identification of chemical inhibitors of E. coli Group 2 capsule biogenesis as anti-virulence agents.

    PubMed

    Goller, Carlos C; Seed, Patrick C

    2010-07-19

    Rising antibiotic resistance among Escherichia coli, the leading cause of urinary tract infections (UTIs), has placed a new focus on molecular pathogenesis studies, aiming to identify new therapeutic targets. Anti-virulence agents are attractive as chemotherapeutics to attenuate an organism during disease but not necessarily during benign commensalism, thus decreasing the stress on beneficial microbial communities and lessening the emergence of resistance. We and others have demonstrated that the K antigen capsule of E. coli is a preeminent virulence determinant during UTI and more invasive diseases. Components of assembly and export are highly conserved among the major K antigen capsular types associated with UTI-causing E. coli and are distinct from the capsule biogenesis machinery of many commensal E. coli, making these attractive therapeutic targets. We conducted a screen for anti-capsular small molecules and identified an agent designated "C7" that blocks the production of K1 and K5 capsules, unrelated polysaccharide types among the Group 2-3 capsules. Herein lies proof-of-concept that this screen may be implemented with larger chemical libraries to identify second-generation small-molecule inhibitors of capsule biogenesis. These inhibitors will lead to a better understanding of capsule biogenesis and may represent a new class of therapeutics.

  20. Chronological Aging Is Associated with Biophysical and Chemical Changes in the Capsule of Cryptococcus neoformans▿‡

    PubMed Central

    Cordero, Radames J. B.; Pontes, Bruno; Guimarães, Allan J.; Martinez, Luis R.; Rivera, Johanna; Fries, Bettina C.; Nimrichter, Leonardo; Rodrigues, Marcio L.; Viana, Nathan B.; Casadevall, Arturo

    2011-01-01

    Does the age of a microbial cell affect its virulence factors? To our knowledge, this question has not been addressed previously, but the answer is of great relevance for chronic infections where microbial cells persist and age in hosts. Cryptococcus neoformans is an encapsulated human-pathogenic fungus notorious for causing chronic infections where cells of variable age persist in tissue. The major virulence factor for C. neoformans is a polysaccharide (PS) capsule. To understand how chronological age could impact the cryptococcal capsule properties, we compared the elastic properties, permeabilities, zeta potentials, and glycosidic compositions of capsules from young and old cells and found significant differences in all parameters measured. Changes in capsular properties were paralleled by changes in PS molecular mass and density, as well as modified antigenic density and antiphagocytic properties. Remarkably, chronological aging under stationary-phase growth conditions was associated with the expression of α-1,3-glucans in the capsule, indicating a new structural capsular component. Our results establish that cryptococcal capsules are highly dynamic structures that change dramatically with chronological aging under prolonged stationary-phase growth conditions. Changes associated with cellular aging in chronic infections could contribute to the remarkable capacity of this fungus to persist in tissues by generating phenotypically and antigenically different capsules. PMID:21968999

  1. Computer simulation and experimental study of the polysaccharide-polysaccharide interaction in the bacteria Azospirillum brasilense Sp245

    NASA Astrophysics Data System (ADS)

    Arefeva, Oksana A.; Kuznetsov, Pavel E.; Tolmachev, Sergey A.; Kupadze, Machammad S.; Khlebtsov, Boris N.; Rogacheva, Svetlana M.

    2003-09-01

    We have studied the conformational properties and molecular dynamics of polysaccharides by using molecular modeling methods. Theoretical and experimental results of polysaccharide-polysaccharide interactions are described.

  2. A common pathway for O-linked protein-glycosylation and synthesis of capsule in Acinetobacter baumannii.

    PubMed

    Lees-Miller, Robert G; Iwashkiw, Jeremy A; Scott, Nichollas E; Seper, Andrea; Vinogradov, Evgeny; Schild, Stefan; Feldman, Mario F

    2013-09-01

    Multi-drug resistant strains of Acinetobacter baumannii are increasingly being isolated in hospitals worldwide. Among the virulence factors identified in this bacterium there is a general O-glycosylation system that appears to be important for biofilm formation and virulence, and the capsular polysaccharide, which is essential for resistance to complement killing. In this work, we identified a locus that is responsible for the synthesis of the O-pentasaccharide found on the glycoproteins. Besides the enzymes required for the assembly of the glycan, additional proteins typically involved in polymerization and transport of capsule were identified within or adjacently to the locus. Mutagenesis of PglC, the initiating glycosyltransferase prevented the synthesis of both glycoproteins and capsule, resulting in abnormal biofilm structures and attenuated virulence in mice. These results, together with the structural analysis of A. baumannii 17978 capsular polysaccharide via NMR, demonstrated that the pentasaccharides that decorate the glycoproteins are also the building blocks for capsule biosynthesis. Two linked subunits, but not longer glycan chains, were detected on proteins via MS. The discovery of a bifurcated pathway for O-glycosylation and capsule synthesis not only provides insight into the biology of A. baumannii but also identifies potential novel candidates for intervention against this emerging pathogen.

  3. Updated Campylobacter jejuni Capsule PCR Multiplex Typing System and Its Application to Clinical Isolates from South and Southeast Asia

    PubMed Central

    Poly, Frédéric; Serichantalergs, Oralak; Kuroiwa, Janelle; Pootong, Piyarat; Mason, Carl; Guerry, Patricia; Parker, Craig T.

    2015-01-01

    Campylobacter jejuni produces a polysaccharide capsule that is the major determinant of the Penner serotyping scheme. This passive slide agglutination typing system was developed in the early 1980’s and was recognized for over two decades as the gold standard for C. jejuni typing. A preliminary multiplex PCR technique covering 17 serotypes was previously developed in order to replace this classic serotyping scheme. Here we report the completion of the multiplex PCR technology that is able to identify all the 47 Penner serotypes types known for C. jejuni. The number of capsule types represented within the 47 serotypes is 35. We have applied this method to a collection of 996 clinical isolates from Thailand, Cambodia and Nepal and were able to successfully determine capsule types of 98% of these. PMID:26630669

  4. Staphylococcus aureus capsular polysaccharide types 5 and 8 reduce killing by bovine neutrophils in vitro.

    PubMed

    Kampen, Annette H; Tollersrud, Tore; Lund, Arve

    2005-03-01

    Isogenic variants of Staphylococcus aureus strain Reynolds expressing either no capsule or capsular polysaccharide (CP) type 5 (CP5) or type 8 (CP8) were used to assess the effect of CP on bacterial killing and the respiratory burst of bovine neutrophils. The effects of antisera specific for CP5 and CP8 were also evaluated. The killing of live bacteria by isolated neutrophils was quantified in a bactericidal assay, while the respiratory burst after stimulation with live bacteria in whole blood was measured by flow cytometry. The expression of a CP5 or CP8 capsule protected the bacteria from being killed by bovine neutrophils in vitro (P <0.001), and the capsule-expressing variants did not stimulate respiratory burst activity in calf whole blood. The addition of serotype-specific antisera increased the killing of the capsule-expressing bacteria and enhanced their stimulating effect in the respiratory burst assay (P <0.01). When the S. aureus variants were grown under conditions known not to promote capsule expression, there were no significant differences between them. The present study demonstrates that the expression of S. aureus CP5 or CP8 confers resistance to opsonophagocytic killing and prevents the bacteria from inducing respiratory burst of bovine neutrophils in vitro and that these effects can be reversed by the addition of serotype-specific antisera.

  5. Exploratory investigations of hypervelocity intact capture spectroscopy.

    PubMed

    Tsou, P; Griffiths, D J

    1993-01-01

    The ability to capture hypervelocity projectiles intact opens a new technique available for hypervelocity research. A determination of the reactions taking place between the projectile and the capture medium during the process of intact capture is extremely important to an understanding of the intact capture phenomenon, to improving the capture technique, and to developing a theory describing the phenomenon. The intact capture of hypervelocity projectiles by underdense media generates spectra, characteristic of the material species of projectile and capture medium involved. Initial exploratory results into real-time characterization of hypervelocity intact capture techniques by spectroscopy include ultra-violet and visible spectra obtained by use of reflecting gratings, transmitting gratings, and prisms, and recorded by photographic and electronic means. Spectrometry proved to be a valuable real-time diagnostic tool for hypervelocity intact capture events, offering understanding of the interactions of the projectile and the capture medium during the initial period and providing information not obtainable by other characterizations. Preliminary results and analyses of spectra produced by the intact capture of hypervelocity aluminum spheres in polyethylene (PE), polystyrene (PS), and polyurethane (PU) foams are presented. Included are tentative emission species identifications, as well as gray body temperatures produced in the intact capture process.

  6. Exploratory investigations of hypervelocity intact capture spectroscopy

    NASA Technical Reports Server (NTRS)

    Tsou, P.; Griffiths, D. J.

    1993-01-01

    The ability to capture hypervelocity projectiles intact opens a new technique available for hypervelocity research. A determination of the reactions taking place between the projectile and the capture medium during the process of intact capture is extremely important to an understanding of the intact capture phenomenon, to improving the capture technique, and to developing a theory describing the phenomenon. The intact capture of hypervelocity projectiles by underdense media generates spectra, characteristic of the material species of projectile and capture medium involved. Initial exploratory results into real-time characterization of hypervelocity intact capture techniques by spectroscopy include ultra-violet and visible spectra obtained by use of reflecting gratings, transmitting gratings, and prisms, and recorded by photographic and electronic means. Spectrometry proved to be a valuable real-time diagnostic tool for hypervelocity intact capture events, offering understanding of the interactions of the projectile and the capture medium during the initial period and providing information not obtainable by other characterizations. Preliminary results and analyses of spectra produced by the intact capture of hypervelocity aluminum spheres in polyethylene (PE), polystyrene (PS), and polyurethane (PU) foams are presented. Included are tentative emission species identifications, as well as gray body temperatures produced in the intact capture process.

  7. 46 CFR 174.185 - Intact stability.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Intact stability. 174.185 Section 174.185 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES PERTAINING TO SPECIFIC VESSEL TYPES Special Rules Pertaining to Offshore Supply Vessels § 174.185 Intact stability....

  8. 46 CFR 174.015 - Intact stability.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Intact stability. 174.015 Section 174.015 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES PERTAINING TO SPECIFIC VESSEL TYPES Special Rules Pertaining to Deck Cargo Barges § 174.015 Intact stability. (a)...

  9. 46 CFR 174.015 - Intact stability.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Intact stability. 174.015 Section 174.015 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES PERTAINING TO SPECIFIC VESSEL TYPES Special Rules Pertaining to Deck Cargo Barges § 174.015 Intact stability. (a)...

  10. 46 CFR 174.015 - Intact stability.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Intact stability. 174.015 Section 174.015 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES PERTAINING TO SPECIFIC VESSEL TYPES Special Rules Pertaining to Deck Cargo Barges § 174.015 Intact stability. (a)...

  11. 46 CFR 174.015 - Intact stability.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Intact stability. 174.015 Section 174.015 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES PERTAINING TO SPECIFIC VESSEL TYPES Special Rules Pertaining to Deck Cargo Barges § 174.015 Intact stability. (a)...

  12. 46 CFR 174.185 - Intact stability.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Intact stability. 174.185 Section 174.185 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES PERTAINING TO SPECIFIC VESSEL TYPES Special Rules Pertaining to Offshore Supply Vessels § 174.185 Intact stability....

  13. 46 CFR 174.015 - Intact stability.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Intact stability. 174.015 Section 174.015 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES PERTAINING TO SPECIFIC VESSEL TYPES Special Rules Pertaining to Deck Cargo Barges § 174.015 Intact stability. (a)...

  14. Reactor for making uniform capsules

    NASA Technical Reports Server (NTRS)

    Wang, Taylor G. (Inventor); Anikumar, Amrutur V. (Inventor); Lacik, Igor (Inventor)

    1999-01-01

    The present invention provides a novel reactor for making capsules with uniform membrane. The reactor includes a source for providing a continuous flow of a first liquid through the reactor; a source for delivering a steady stream of drops of a second liquid to the entrance of the reactor; a main tube portion having at least one loop, and an exit opening, where the exit opening is at a height substantially equal to the entrance. In addition, a method for using the novel reactor is provided. This method involves providing a continuous stream of a first liquid; introducing uniformly-sized drops of the second liquid into the stream of the first liquid; allowing the drops to react in the stream for a pre-determined period of time; and collecting the capsules.

  15. Sequence analysis of serotype-specific synthesis regions II of Haemophilus influenzae serotypes c and d: evidence for common ancestry of capsule synthesis in Pasteurellaceae and Neisseria meningitidis.

    PubMed

    Lâm, Thiên-Trí; Claus, Heike; Frosch, Matthias; Vogel, Ulrich

    2011-06-01

    Sequencing of yet unknown Haemophilus influenzae serotype c (Hic) and d (Hid) capsule synthesis regions II revealed four (ccs1-4) and five (dcs1-5) open reading frames, respectively. The inferred gene functions were in line with capsular polysaccharide structures. One or more proteins encoded by the Hic capsule synthesis region II showed similarity to Actinobacillus pleuropneumoniae serotype 1 and Actinobacillus suis K1 enzymes. Orthologues to the complete operon were observed in Actinobacillus minor strain 202, where even the gene order was conserved. Furthermore, Ccs4 was related to the capsule O-acetyltransferase of Neisseria meningitidis serogroup W-135. For the Hid locus, similarities to Hie, Mannheimia haemolytica A1 and N. meningitidis serogroup A were identified and the succession of genes was similar in the different species. The resemblance of genes and gene organization found for Hic and Hid with other species suggested horizontal gene transfer during capsule evolution across the bacterial classes.

  16. Malignant schwannoma of kidney capsule.

    PubMed

    Romics, I; Bach, D; Beutler, W

    1992-11-01

    This report is of a malignant schwannoma originating in the capsule of the right kidney. Using sonography, nephroangiography, cavography, computer tomography, and bone scanning, metastases in the kidney or a retroperitoneal tumor could be diagnosed. After transperitoneal exploration, the right kidney and mesenteric metastases were removed. Due to tumor infiltration into the liver and tumor masses in the retroperitoneum, only nephrectomy and palliative excision of retroperitoneal metastases were done. Pulmonary metastases developed postoperatively, and the patient died three months after the operation.

  17. Capsule endoscopy: The road ahead

    PubMed Central

    Singeap, Ana-Maria; Stanciu, Carol; Trifan, Anca

    2016-01-01

    Since its introduction into clinical practice 15 years ago, capsule endoscopy (CE) has become the first-line investigation procedure in some small bowel pathologies, and more recently, dedicated esophageal and colon CE have expanded the fields of application to include the upper and lower gastrointestinal disorders. During this time, CE has become increasingly popular among gastroenterologists, with more than 2 million capsule examinations performed worldwide, and nearly 3000 PubMed-listed studies on its different aspects published. This huge interest in CE may be explained by its non-invasive nature, patient comfort, safety, and access to anatomical regions unattainable via conventional endoscopy. However, CE has several limitations which impede its wider clinical applications, including the lack of therapeutic capabilities, inability to obtain biopsies and control its locomotion. Several research groups are currently working to overcome these limitations, while novel devices able to control capsule movement, obtain high quality images, insufflate the gut lumen, perform chromoendoscopy, biopsy of suspect lesions, or even deliver targeted drugs directly to specific sites are under development. Overlooking current limitations, especially as some of them have already been successfully surmounted, and based on the tremendous progress in technology, it is expected that, by the end of next 15 years, CE able to perform both diagnostic and therapeutic procedures will remain the major form of digestive endoscopy. This review summarizes the literature that prognosticates about the future developments of CE. PMID:26755883

  18. Spectrum of pneumococcal serotype 11A variants results from incomplete loss of capsule O-acetylation.

    PubMed

    Calix, Juan J; Brady, Allison M; Du, Victor Y; Saad, Jamil S; Nahm, Moon H

    2014-03-01

    Streptococcus pneumoniae is a significant bacterial pathogen that expresses >90 capsule serotypes. Conventional serotyping methods assume that each serotype is a genetically and antigenically distinct entity; however, recent investigations have revealed pneumococcal isolates that cannot be unambiguously serotyped because they share the properties of more than one serotype. Here, we employed a novel serotyping method and NMR spectroscopy to examine clinical isolates sharing properties of serotypes 11A and 11E. These ambiguous clinical isolates were provisionally named 11A variant (11Av) isolates. Serotype 11A pneumococci characteristically express capsule β-galactose-6-O-acetylation (βGal6OAc) mediated by the capsule synthesis gene wcjE, while 11E strains contain loss-of-function mutations in wcjE and completely lack the expression of βGal6OAc. Although 11Av isolates also contained mutated wcjE alleles, 11Av clinical isolates were composed of antigenically homogeneous bacteria expressing reduced amounts of 11A-specific capsule antigen. NMR data confirmed reduced but detectable amounts of βGal6OAc on 11Av capsule polysaccharide. Furthermore, the transformation of strains with wcjE alleles from 11Av strains was sufficient to restore partial βGal6OAc in an 11E background. We conclude that, instead of being distinct entities, serotypes 11A and 11E represent two extremes of an antigenic spectrum resulting from variable capsule O-acetylation secondary to heterologous wcjE mutations. These findings challenge whether all clinically relevant pneumococci can be definitively categorized into distinct serotypes.

  19. Pbx Proteins in Cryptococcus neoformans Cell Wall Remodeling and Capsule Assembly

    PubMed Central

    Kumar, Pardeep; Heiss, Christian; Santiago-Tirado, Felipe H.; Black, Ian; Azadi, Parastoo

    2014-01-01

    The cryptococcal capsule is a critical virulence factor of an important pathogen, but little is known about how it is associated with the cell or released into the environment. Two mutants lacking PBX1 and PBX2 were found to shed reduced amounts of the capsule polysaccharide glucuronoxylomannan (GXM). Nuclear magnetic resonance, composition, and physical analyses showed that the shed material was of normal mass but was slightly enriched in xylose. In contrast to previous reports, this material contained no glucose. Notably, the capsule fibers of pbxΔ mutant cells grown under capsule-inducing conditions were present at a lower than usual density and were loosely attached to the cell wall. Mutant cell walls were also defective, as indicated by phenotypes including abnormal cell morphology, reduced mating filamentation, and altered cell integrity. All observed phenotypes were shared between the two mutants and exacerbated in a double mutant. Consistent with a role in surface glycan synthesis, the Pbx proteins localized to detergent-resistant membrane domains. These results, together with the sequence motifs in the Pbx proteins, suggest that Pbx1 and Pbx2 are redundant proteins that act in remodeling the cell wall to maintain normal cell morphology and precursor availability for other glycan synthetic processes. Their absence results in aberrant cell wall growth and metabolic imbalance, which together impact cell wall and capsule synthesis, cell morphology, and capsule association. The surface changes also lead to increased engulfment by host phagocytes, consistent with the lack of virulence of pbx mutants in animal models. PMID:24585882

  20. Allelic Variation of the Capsule Promoter Diversifies Encapsulation and Virulence In Streptococcus pneumoniae

    PubMed Central

    Wen, Zhensong; Liu, Yanni; Qu, Fen; Zhang, Jing-Ren

    2016-01-01

    The polysaccharide capsule is the major virulence factor of Streptococcus pneumoniae (pneumococcus), a major human pathogen. The sequences in the promoter and coding regions of the capsule gene locus undergo extensive variations through the natural transformation-mediated horizontal gene transfer. The sequence variations in the coding region have led to at least 97 capsular serotypes. However, it remains unclear whether the sequence polymorphisms in the promoter region have any biological significance. In this study, we determined the sequences of the cps promoter region from 225 invasive pneumococcal isolates, and identified modular composition and remarkable inter-strain sequence variations in this region. The strain-to strain variations in the cps promoter are characterized by diversity in sequence and size, mosaic combinations of nucleotide polymorphisms and sequence modules, selective preservation of the sequence combinations, and promiscuous assortments of the sequences between the promoter and coding regions. Isogenic pneumococci carrying allelic variants of the cps promoter displayed significant differences in the transcription of the capsule genes, capsule production, adhesion to host epithelial cells, anti-phagocytosis and virulence in mouse bacteremia model. This study has thus indicated that the sequence polymorphisms in the cps promoter represent a novel mechanism for fine-tuning the level of encapsulation and virulence among S. pneumoniae strains. PMID:27465908

  1. Perform Ultrasonic Testing on Cs Capsule Overpacks

    SciTech Connect

    DAVIS, S.J.

    2000-04-06

    This procedure provides a safe, uniform method for the performance of the ultrasonic weld inspection of the Cesium capsule overpacks. The inspection system will detect cracks, lack of fusion, and lack of penetration. This computer controlled automated system will perform the examination once the capsule overpack has been placed in the pool cell. Examination of the capsule overpacks will be in accordance with drawing H-283014, REV. 0 ,and a certified NDE examiner will perform the test procedure, provide analysis, and test documentation.

  2. Work capsule for lightweight hydrostatic machines

    NASA Astrophysics Data System (ADS)

    Hunt, M. S.

    1983-02-01

    The theoretical feasibility of designing a lightweight flexible capsule suitable for use as the basic actuating means in the place of the conventional piston and cylinder in a high pressure hydrostatic machine was investigated. The idea was suggested by the high strength/modulus ratio obtained with glass fiber reinforced composites. It is found that the combined effect of hoop and bend stresses in the flexible walls of a bellows type capsule imposes severe limitations on the work output of the capsule.

  3. Colon Capsule Endoscopy: Review and Perspectives

    PubMed Central

    Modayil, Rani; Stavropoulos, Stavros

    2016-01-01

    Colon capsule endoscopy utilizing PillCam COLON 2 capsule allows for visualization potentially of the entire colon and is currently approved for patients who cannot withstand the rigors of traditional optical colonoscopy (OC) and associated sedation as well as those that had an OC that was incomplete for technical reasons other than a poor preparation. We will then describe the prior experience and current status of colon capsule endoscopy. PMID:27698664

  4. Rheologically interesting polysaccharides from yeasts

    NASA Technical Reports Server (NTRS)

    Petersen, G. R.; Nelson, G. A.; Cathey, C. A.; Fuller, G. G.

    1989-01-01

    We have examined the relationships between primary, secondary, and tertiary structures of polysaccharides exhibiting the rheological property of friction (drag) reduction in turbulent flows. We found an example of an exopolysaccharide from the yeast Cryptococcus laurentii that possessed high molecular weight but exhibited lower than expected drag reducing activity. Earlier correlations by Hoyt showing that beta 1 --> 3, beta 2 --> 4, and alpha 1 --> 3 linkages in polysaccharides favored drag reduction were expanded to include correlations to secondary structure. The effect of sidechains in a series of gellan gums was shown to be related to sidechain length and position. Disruption of secondary structure in drag reducing polysaccharides reduced drag reducing activity for some but not all exopolysaccharides. The polymer from C. laurentii was shown to be more stable than xanthan gum and other exopolysaccharides under the most vigorous of denaturing conditions. We also showed a direct relationship between extensional viscosity measurements and the drag reducing coefficient for four exopolysaccharides.

  5. Genesis Sample Return Capsule Overview

    NASA Technical Reports Server (NTRS)

    Willcockson, Bill

    2005-01-01

    I. Simple Entry Capsule Concept: a) Spin-Stabilized/No Active Control Systems; b) Ballistic Entry for 11.04 km/sec Velocity; c) No Heatshield Separation During Entry; d) Parachute Deploy via g-Switch + Timer. II. Stardust Design Inheritance a) Forebody Shape; b) Seal Concepts; c) Parachute Deploy Control; d) Utah Landing Site (UTTR). III. TPS Systems a) Heatshield - Carbon-Carbon - First Planetary Entry; b) Backshell - SLA-561V - Flight Heritage from Pathfinder, MER; d) Forebody Structural Penetrations Aerothermal and TPS Design Process has the Same Methodology as Used for Pathfinder, MER Flight Vehicles.

  6. Some ultrastructural information on intact, living bacterial cells and related cell-wall fragments as given by FTIR

    NASA Astrophysics Data System (ADS)

    Naumann, D.

    1984-05-01

    Living bacterial cells of Staphylococcus aureus have been measured from aqueous suspensions taking advantage of the solvent subtraction capabilities of FTIR. All spectral features, between 1800-800 cm -1, of the intact cells could be measured with a reproducibility of better than ±5% when applying strict metabolic control of cell growth and a highly standardized experimental procedure prior to IR measurements. IR bands near 1745, 1656, 1547, 1240 and 1200-1000 cm -1were tentatively assigned to: CO stretching of ester groups, amide I and amide II bands of the various peptides and proteins, asymmetric stretching of phosphate groups and complex vibrational modes resulting from polysaccharidal compounds, respectively. Absorbance subtraction of IR spectra of different intact baterial cells and cell-wall preparations yielded reasonable results on structural variations accompanying: (i) cell growth, (ii) use of different growth media, (iii) chemical treatment of cells and (iv) biochemical isolation processes of cell walls from the intact cells.

  7. Membrane structure in isolated and intact myelins.

    PubMed Central

    Inouye, H; Karthigasan, J; Kirschner, D A

    1989-01-01

    The biochemical composition of myelin and the topology of its constituent lipids and proteins are typically studied using membranes that have been isolated from whole, intact tissue using procedures involving hypotonic shock and sucrose density gradient centrifugation. To what extent, however, are the structure and intermembrane interactions of isolated myelin similar to those of intact myelin? We have previously reported that intact and isolated myelins do not always show identical myelin periods, indicating a difference in membrane-membrane interactions. The present study addresses the possibility that this is due to altered membrane structure. Because x-ray scattering from isolated myelin sometimes consists of overlapping Bragg reflections or is continuous, we developed nonlinear least squares procedures for analyzing the total intensity distribution after film scaling, background subtraction, and Lorentz correction. We calculated electron density profiles of isolated myelin for comparison with membrane profiles from intact myelin. The change in the width of the extracellular space and the relative invariance of the cytoplasmic space as a function of pH and ionic strength that we previously found for intact nerve was largely paralleled by isolated myelin. There were two exceptions: isolated CNS myelin was resistant to swelling under all conditions, and isolated PNS myelin in hypotonic saline showed indefinite swelling at the extracellular apposition. However, electron density profiles of isolated myelins, calculated to 30 A resolution, did not show any major change in structure compared with intact myelin that could account for the differences in interactions. PMID:2752082

  8. Polysaccharide-Modified Synthetic Polymeric Biomaterials

    PubMed Central

    Baldwin, Aaron D.; Kiick, Kristi L.

    2010-01-01

    This review presents an overview of polysaccharide-conjugated synthetic polymers and their use in tissue-engineered scaffolds and drug-delivery applications. This topic will be divided into four categories: (1) polymeric materials modified with non-mammalian polysaccharides such as alginate, chitin, and dextran; (2) polymers modified with mammalian polysaccharides such as hyaluronan, chondroitin sulfate, and heparin; (3) multi-polysaccharide-derivatized polymer conjugate systems; and (4) polymers containing polysaccharide-mimetic molecules. Each section will discuss relevant conjugation techniques, analysis, and the impact of these materials as micelles, particles, or hydrogels used in in-vitro and in-vivo biomaterial applications. PMID:20091875

  9. Polysaccharide-modified synthetic polymeric biomaterials.

    PubMed

    Baldwin, Aaron D; Kiick, Kristi L

    2010-01-01

    This review presents an overview of polysaccharide-conjugated synthetic polymers and their use in tissue-engineered scaffolds and drug-delivery applications. This topic will be divided into four categories: (1) polymeric materials modified with non-mammalian polysaccharides such as alginate, chitin, and dextran; (2) polymers modified with mammalian polysaccharides such as hyaluronan, chondroitin sulfate, and heparin; (3) multi-polysaccharide-derivatized polymer conjugate systems; and (4) polymers containing polysaccharide-mimetic molecules. Each section will discuss relevant conjugation techniques, analysis, and the impact of these materials as micelles, particles, or hydrogels used in in-vitro and in-vivo biomaterial applications. PMID:20091875

  10. The future of wireless capsule endoscopy.

    PubMed

    Swain, Paul

    2008-07-14

    We outline probable and possible developments with wireless capsule endoscopy. It seems likely that capsule endoscopy will become increasingly effective in diagnostic gastrointestinal endoscopy. This will be attractive to patients especially for cancer or varices detection because capsule endoscopy is painless and is likely to have a higher take up rate compared to conventional colonoscopy and gastroscopy. Double imager capsules with increased frame rates have been used to image the esophagus for Barrett's and esophageal varices. The image quality is not bad but needs to be improved if it is to become a realistic substitute for flexible upper and lower gastrointestinal endoscopy. An increase in the frame rate, angle of view, depth of field, image numbers, duration of the procedure and improvements in illumination seem likely. Colonic, esophageal and gastric capsules will improve in quality, eroding the supremacy of flexible endoscopy, and become embedded into screening programs. Therapeutic capsules will emerge with brushing, cytology, fluid aspiration, biopsy and drug delivery capabilities. Electrocautery may also become possible. Diagnostic capsules will integrate physiological measurements with imaging and optical biopsy, and immunologic cancer recognition. Remote control movement will improve with the use of magnets and/or electrostimulation and perhaps electromechanical methods. External wireless commands will influence capsule diagnosis and therapy and will increasingly entail the use of real-time imaging. However, it should be noted that speculations about the future of technology in any detail are almost always wrong.

  11. Streptococcus suis Serotype 2 Capsule In Vivo.

    PubMed

    Auger, Jean-Philippe; Meekhanon, Nattakan; Okura, Masatoshi; Osaki, Makoto; Gottschalk, Marcelo; Sekizaki, Tsutomu; Takamatsu, Daisuke

    2016-10-01

    Many Streptococcus suis isolates from porcine endocarditis in slaughterhouses have lost their capsule and are considered avirulent. However, we retrieved capsule- and virulence-recovered S. suis after in vivo passages of a nonencapsulated strain in mice, suggesting that nonencapsulated S. suis are still potentially hazardous for persons in the swine industry. PMID:27648583

  12. Streptococcus suis Serotype 2 Capsule In Vivo

    PubMed Central

    Auger, Jean-Philippe; Meekhanon, Nattakan; Okura, Masatoshi; Osaki, Makoto; Gottschalk, Marcelo; Sekizaki, Tsutomu

    2016-01-01

    Many Streptococcus suis isolates from porcine endocarditis in slaughterhouses have lost their capsule and are considered avirulent. However, we retrieved capsule- and virulence-recovered S. suis after in vivo passages of a nonencapsulated strain in mice, suggesting that nonencapsulated S. suis are still potentially hazardous for persons in the swine industry. PMID:27648583

  13. The Vi capsular polysaccharide enables Salmonella enterica serovar typhi to evade microbe-guided neutrophil chemotaxis.

    PubMed

    Wangdi, Tamding; Lee, Cheng-Yuk; Spees, Alanna M; Yu, Chenzhou; Kingsbury, Dawn D; Winter, Sebastian E; Hastey, Christine J; Wilson, R Paul; Heinrich, Volkmar; Bäumler, Andreas J

    2014-08-01

    Salmonella enterica serovar Typhi (S. Typhi) causes typhoid fever, a disseminated infection, while the closely related pathogen S. enterica serovar Typhimurium (S. Typhimurium) is associated with a localized gastroenteritis in humans. Here we investigated whether both pathogens differ in the chemotactic response they induce in neutrophils using a single-cell experimental approach. Surprisingly, neutrophils extended chemotactic pseudopodia toward Escherichia coli and S. Typhimurium, but not toward S. Typhi. Bacterial-guided chemotaxis was dependent on the presence of complement component 5a (C5a) and C5a receptor (C5aR). Deletion of S. Typhi capsule biosynthesis genes markedly enhanced the chemotactic response of neutrophils in vitro. Furthermore, deletion of capsule biosynthesis genes heightened the association of S. Typhi with neutrophils in vivo through a C5aR-dependent mechanism. Collectively, these data suggest that expression of the virulence-associated (Vi) capsular polysaccharide of S. Typhi obstructs bacterial-guided neutrophil chemotaxis.

  14. Fibrous capsule formation around titanium and copper.

    PubMed

    Suska, Felicia; Emanuelsson, Lena; Johansson, Anna; Tengvall, Pentti; Thomsen, Peter

    2008-06-15

    Previous studies suggest that implant material properties influence the quality and quantity of fibrous capsule around the implant. However, the precise relation between material surface chemistry, early inflammatory response, and fibrous subsequent repair outcome is still unknown. Titanium (Ti) and copper (Cu), surfaces with different inflammatory potential, were implanted subcutaneously in rats and retrieved fibrous capsules were analyzed after 28 and 56 days. Histological examinations show pronounced differences in capsule morphology. The fibrous capsule around Ti was thinner than that around Cu, with less number of the inflammatory cells in the layer close to the implant surface, and less and smaller blood vessels. The capsule around Cu was thick, with a large number of the inflammatory cells, particularly macrophages and giant cells, and increased number of blood vessels. Our study suggests that material surface properties, which initiate early, multiple cellular inflammatory events, are also associated with increased fibrosis and angiogenesis during repair phase. PMID:17896778

  15. Trapped translocation intermediates establish the route for export of capsular polysaccharides across Escherichia coli outer membranes.

    PubMed

    Nickerson, Nicholas N; Mainprize, Iain L; Hampton, Lauren; Jones, Michelle L; Naismith, James H; Whitfield, Chris

    2014-06-01

    The outer membrane (OM) of Gram-negative bacteria is designed to exclude potentially harmful molecules. This property presents a challenge for bacteria that must secrete proteins and large glycoconjugates to grow, divide, and persist. Proteins involved in trafficking such molecules have been identified, but their precise roles are often unresolved due to the difficulty in capturing "snapshots" during the export pathway. Wza is the prototype for the large family of OM polysaccharide export proteins. In Escherichia coli, Wza is essential for the assembly of a capsule, a protective surface coat composed of long-chain polysaccharides. Wza creates an octameric α-helical channel spanning the OM, but the bulk of the protein exists as a large periplasmic structure enclosing an extensive lumen. Residues within the lumen of Wza were targeted for site-specific incorporation of the UV photo-cross-linkable unnatural amino acid p-benzoyl-L-phenylalanine. Using this in vivo photo-cross-linking strategy, we were able to trap polysaccharide translocation intermediates within the lumen of Wza, providing the first unequivocal evidence to our knowledge that nascent capsular polysaccharide chains exit the cell through the Wza portal.

  16. Polysaccharides templates for assembly of nanosilver.

    PubMed

    Emam, Hossam E; Ahmed, Hanan B

    2016-01-01

    Polysaccharides are particularly attractive in biomedical applications due to its biodegradability and biocompatibility. In addition to its ecofriendly effects and easy processing into different hydrogel shapes, made polysaccharides used on a large scale as suitable media for preparation of silver nanoparticles (AgNPs). In spite of, most of polysaccharides are water insoluble, but it has shown to be quite efficient capping agents and/or nanoreactor matrices for production of AgNPs. Several methods have been developed to get the benefit of multi-functionality for polysaccharides' macromolecules in preparation of AgNPs. Therefore, recently, preparation of nanosilver using different polysaccharides have been the focus of an exponentially increasing number of works devoted to develop nanocomposites by blending AgNPs with different polysaccharides matrices. The current review represents a wide survey for the published studies which interested in using of polysaccharides in nanosilver preparations.

  17. Thermoregulation of capsule production by Streptococcus pyogenes.

    PubMed

    Kang, Song Ok; Wright, Jordan O; Tesorero, Rafael A; Lee, Hyunwoo; Beall, Bernard; Cho, Kyu Hong

    2012-01-01

    The capsule of Streptococcus pyogenes serves as an adhesin as well as an anti-phagocytic factor by binding to CD44 on keratinocytes of the pharyngeal mucosa and the skin, the main entry sites of the pathogen. We discovered that S. pyogenes HSC5 and MGAS315 strains are further thermoregulated for capsule production at a post-transcriptional level in addition to the transcriptional regulation by the CovRS two-component regulatory system. When the transcription of the hasABC capsular biosynthetic locus was de-repressed through mutation of the covRS system, the two strains, which have been used for pathogenesis studies in the laboratory, exhibited markedly increased capsule production at sub-body temperature. Employing transposon mutagenesis, we found that CvfA, a previously identified membrane-associated endoribonuclease, is required for the thermoregulation of capsule synthesis. The mutation of the cvfA gene conferred increased capsule production regardless of temperature. However, the amount of the capsule transcript was not changed by the mutation, indicating that a post-transcriptional regulator mediates between CvfA and thermoregulated capsule production. When we tested naturally occurring invasive mucoid strains, a high percentage (11/53, 21%) of the strains exhibited thermoregulated capsule production. As expected, the mucoid phenotype of these strains at sub-body temperature was due to mutations within the chromosomal covRS genes. Capsule thermoregulation that exhibits high capsule production at lower temperatures that occur on the skin or mucosal surface potentially confers better capability of adhesion and invasion when S. pyogenes penetrates the epithelial surface.

  18. Biosynthesis of the Escherichia coli K1 group 2 polysialic acid capsule occurs within a protected cytoplasmic compartment.

    PubMed

    Steenbergen, Susan M; Vimr, Eric R

    2008-06-01

    Capsular polysaccharides are important virulence determinants in a wide range of invasive infectious diseases. Although capsule synthesis has been extensively investigated, understanding polysaccharide export from the cytoplasm to the external environment has been more difficult. Here we present the results of a novel protection assay indicating that synthesis and export of the Escherichia coli K1 group 2 capsular polysialic acid (K1 antigen) occur within a protected subcellular compartment designated the sialisome. In addition to the polymerase encoded by neuS, localization and complementation analyses indicated that the sialisome includes the accessory membrane protein NeuE. The requirement for NeuE was suppressed by overproducing NeuS, suggesting that NeuE functions by stabilizing the polymerase or facilitating its assembly in the sialisome. Although an interaction between NeuE and NeuS could not be demonstrated with a bacterial two-hybrid system that reconstitutes an intracellular cell-signalling pathway, interactions between NeuS and KpsC as well as other sialisome components were detected. The combined results provide direct evidence for specific protein-protein interactions in the synthesis and export of group 2 capsular polysaccharides under in vivo conditions. The approaches developed here will facilitate further dissection of the sialisome, suggesting similar methodology for understanding the biosynthesis of other group 2 capsules.

  19. Loss of Very-Long O-Antigen Chains Optimizes Capsule-Mediated Immune Evasion by Salmonella enterica Serovar Typhi

    PubMed Central

    Crawford, Robert W.; Wangdi, Tamding; Spees, Alanna M.; Xavier, Mariana N.; Tsolis, Renée M.; Bäumler, Andreas J.

    2013-01-01

    ABSTRACT Expression of capsular polysaccharides is a variable trait often associated with more-virulent forms of a bacterial species. For example, typhoid fever is caused by the capsulated Salmonella enterica serovar Typhi, while nontyphoidal Salmonella serovars associated with gastroenteritis are noncapsulated. Here we show that optimization of the immune evasive properties conferred by the virulence-associated (Vi) capsular polysaccharide involved an additional alteration to the cell envelope of S. Typhi, namely inactivation of the fepE gene, encoding the regulator of very-long O-antigen chains. Introduction of the capsule-encoding viaB locus into the nontyphoidal S. enterica serovar Typhimurium reduced complement deposition in vitro and intestinal inflammation in a mouse colitis model. However, both phenotypes were markedly enhanced when the viaB locus was introduced into an S. Typhimurium fepE mutant, which lacks very-long O-antigen chains. Collectively, these data suggest that during the evolution of the S. Typhi lineage, loss of very-long O-antigen chains by pseudogene formation was an adaptation to maximize the anti-inflammatory properties of the Vi capsular polysaccharide. PMID:23860765

  20. Elastic constants of the human lens capsule.

    PubMed

    Fisher, R F

    1969-03-01

    1. A technique is described whereby the elasticity of the human lens capsule has been determined at birth and throughout life. This technique requires three separate determinations: (a) thickness; (b) stress and strain; (c) Poisson's ratio; (a) the capsule was clamped between accurately perforated ground glass plates and its thickness determined by noting the change in depth of focus between Latex spherules adhering to its upper and lower surfaces; (b) the undisturbed capsule was then placed in a specially designed glass distension apparatus and the relationship between volume and pressure recorded when it was distended with isotonic saline. The permeability of the capsule was also measured; (c) in some cases Poisson's ratio was determined by measuring the change of thickness of the capsule and the height to which it rose when distended with isotonic saline at different pressures. An apparatus was designed for this purpose.2. The average thickness of the anterior capsule increases from birth until about the 60th year but thereafter it decreases slightly.3. Poisson's ratio was about 0.47 for both cat and human capsule, and no significant variations with age in human capsule could be detected.4. Corrected volume pressure curves obeyed Hook's law almost to the point of capsule rupture.5. In childhood Young's Modulus of elasticity is about 6 x 10(7) dyn/cm(2) and decreases to 3 x 10(7) dyn/cm(2) at 60 and 1.5 x 10(7) dyn/cm(2) in extreme old age.6. The ultimate tensile stress was 2.3 x 10(7) dyn/cm(2) in young capsules and 0.7 x 10(7) dyn/cm(2) in old ones. The maximum percentage elongation was 29 per cent and independent of age.7. The implications of these findings are discussed in relation to(a) the mechanical properties of the lens capsule;(b) the ageing of the lens capsule and basement membranes; and(c) the decrease in elasticity of the lens capsule as a cause of presbyopia.

  1. Hydrodynamick instabilities on ICF capsules

    SciTech Connect

    Haan, S.W.

    1991-06-07

    This article summarizes our current understanding of hydrodynamic instabilities as relevant to ICF. First we discuss classical, single mode Rayleigh-Taylor instability, and nonlinear effects in the evolution of a single mode. Then we discuss multimode systems, considering: (1) the onset of nonlinearity; (2) a second order mode coupling theory for weakly nonlinear effects, and (3) the fully nonlinear regime. Two stabilization mechanisms relevant to ICF are described next: gradient scale length and convective stabilization. Then we describe a model which is meant to estimate the weakly nonlinear evolution of multi-mode systems as relevant to ICF, given the short-wavelength stabilization. Finally, we discuss the relevant code simulation capability, and experiments. At this time we are quite optimistic about our ability to estimate instability growth on ICF capsules, but further experiments and simulations are needed to verify the modeling. 52 refs.

  2. Calorie restriction and susceptibility to intact pathogens

    PubMed Central

    2008-01-01

    Long-term calorie restriction (CR) causes numerous physiological changes that ultimately increase mean and maximum lifespan of most species examined to date. One physiological change that occurs with CR is enhanced immune function, as tested using antigens and mitogens to stimulate an immune response. Fewer studies have used intact pathogen exposure to test whether the enhanced capacity of the immune response during CR actually decreases susceptibility of hosts to their pathogens. So far, studies using intact bacteria, virus, and helminth worm exposure indicate that, despite similar or enhanced immune system function, CR hosts are more susceptible to infection by intact pathogens than their fully fed counterparts. Long-term CR studies that examine susceptibility to a variety of parasite taxa will help determine if direct CR or CR mimetics will be beneficial to people living in pathogen-rich environments. PMID:19424864

  3. Unique lipid anchor attaches Vi antigen capsule to the surface of Salmonella enterica serovar Typhi.

    PubMed

    Liston, Sean D; Ovchinnikova, Olga G; Whitfield, Chris

    2016-06-14

    Polysaccharide capsules are surface structures that are critical for the virulence of many Gram-negative pathogenic bacteria. Salmonella enterica serovar Typhi is the etiological agent of typhoid fever. It produces a capsular polysaccharide known as "Vi antigen," which is composed of nonstoichiometrically O-acetylated α-1,4-linked N-acetylgalactosaminuronic acid residues. This glycan is a component of currently available vaccines. The genetic locus for Vi antigen production is also present in soil bacteria belonging to the genus Achromobacter Vi antigen assembly follows a widespread general strategy with a characteristic glycan export step involving an ATP-binding cassette transporter. However, Vi antigen producers lack the enzymes that build the conserved terminal glycolipid characterizing other capsules using this method. Achromobacter species possess a Vi antigen-specific depolymerase enzyme missing in S enterica Typhi, and we exploited this enzyme to isolate acylated Vi antigen termini. Mass spectrometry analysis revealed a reducing terminal N-acetylhexosamine residue modified with two β-hydroxyl acyl chains. This terminal structure resembles one half of lipid A, the hydrophobic portion of bacterial lipopolysaccharides. The VexE protein encoded in the Vi antigen biosynthesis locus shares similarity with LpxL, an acyltransferase from lipid A biosynthesis. In the absence of VexE, Vi antigen is produced, but its physical properties are altered, its export is impaired, and a Vi capsule structure is not assembled on the cell surface. The structure of the lipidated terminus dictates a unique assembly mechanism and has potential implications in pathogenesis and vaccine production. PMID:27226298

  4. [Evaluation of nopal capsules in diabetes mellitus].

    PubMed

    Frati Munari, A C; Vera Lastra, O; Ariza Andraca, C R

    1992-01-01

    To find out if commercial capsules with dried nopal (prickle-pear cactus, Opuntia ficus indica may have a role in the management of diabetes mellitus, three experiments were performed: 30 capsules where given in fasting condition to 10 diabetic subjects and serum glucose was measured through out 3 hours; a control test was performed with 30 placebo capsules. OGTT with previous intake of 30 nopal or placebo capsules was performed in ten healthy individuals. In a crossover and single blinded study 14 diabetic patients withdrew the oral hypoglycemic treatment and received 10 nopal or placebo capsules t.i.d. during one week; serum glucose, cholesterol and tryglycerides levels were measured before and after each one-week period. Five healthy subjects were also studied in the same fashion. Opuntia capsules did not show acute hypoglycemic effect and did not influence OGTT. In diabetic patients serum glucose, cholesterol and tryglycerides levels did not change with Opuntia, but they increased with placebo (P < 0.01 glucose and cholesterol, P = NS triglycerides). In healthy individuals glycemia did not change with nopal, while cholesterol and triglycerides decreased (P < 0.01 vs. placebo). The intake of 30 Opuntia capsules daily in patients with diabetes mellitus had a discrete beneficial effect on glucose and cholesterol. However this dose is unpractical and at present it is not recommended in the management of diabetes mellitus. PMID:1307994

  5. [Karyosphere capsule in Tribolium castaneum oocytes].

    PubMed

    Batalova, F M; Bogoliubov, D S

    2013-01-01

    Structure and composition of the karyosphere (karyosome) capsule were studied in the oocytes of a laboratory insect, Tribolium castaneum, with the use of electron microscopy and immunoelectron cytochemistry. Basing on the study of nuclear structure dynamics, we distinguished 8 stages that characterize the period of oocyte growth. At the diplotene stage, T. castaneum oocyte chromosomes conjoin early into a compact karyosphere, but a significant chromatin condensation does not occur. The process of karyosphere formation is accompanied by the development of an extensive extrachromosome capsule surrounding chromatin. The capsule consists of a material of different morphological types. Significant molecular components of the T. castaneum karyosphere capsule are represented by the proteins of nuclear matrix including F-actin and lamin B. Besides the structural proteins, the Sm proteins of small nuclear (sn) RNPs and mature 2,2,7-trimethyl guanosine (TMG) 5'-capped snRNAs are revealed immunocytochemically in the karyosphere capsule. The obtained data can form a basis for further expansion of ideas on the functions of the karyosphere capsule as a specialized extrachromosomal nuclear domain of the oocytes. We believe that the T. castaneum karyosphere capsule plays not only a structural role, but may be involved directly in the processes related to gene expression.

  6. Asymmetric Membrane Osmotic Capsules for Terbutaline Sulphate

    PubMed Central

    Gobade, N. G.; Koland, Marina; Harish, K. H.

    2012-01-01

    The aim of the present study was to design an asymmetric membrane capsule, an osmotic pump-based drug delivery system of ethyl cellulose for controlled release of terbutaline sulphate. asymmetric membrane capsules contains pore-forming water soluble additive, sorbitol in different concentrations in the capsule shell membrane, which after coming in contact with water, dissolves, resulting in an in situ formation of a microporous structure. The terbutaline sulphate is a β-adrenoreceptor agonist widely used in the treatment of asthma. The oral dosage regimen of terbutaline sulphate is 5 mg twice or thrice daily, the plasma half-life is approximate 3-4 h and it produces GI irritation with extensive first pass metabolism. Hence, terbutaline sulphate was chosen as a model drug with an aim to develop controlled release system. Different formulations of ethyl cellulose were prepared by phase inversion technique using different concentrations of sorbitol as pore forming agent. It was found that the thickness of the prepared asymmetric membrane capsules was increased with increase in concentration of ethyl cellulose and pore forming agent, i.e. sorbitol. The dye release study in water and 10% sodium chloride solution indicates that, the asymmetric membrane capsules follow osmotic principle to release content. The pores formed due to sorbitol were confirmed by microscopic observation of transverse section of capsule membrane. Data of in vitro release study of terbutaline sulphate from asymmetric membrane capsules indicated that, the capsules prepared with 10% and 12.5% of ethyl cellulose and 25% of sorbitol released as much as 97.44% and 76.27% in 12 h, respectively with zero order release rate. Hence asymmetric membrane capsule of 10% ethyl cellulose and 25% of sorbitol is considered as optimum for controlled oral delivery of terbutaline sulphate. PMID:23204625

  7. Asymmetric membrane osmotic capsules for terbutaline sulphate.

    PubMed

    Gobade, N G; Koland, Marina; Harish, K H

    2012-01-01

    The aim of the present study was to design an asymmetric membrane capsule, an osmotic pump-based drug delivery system of ethyl cellulose for controlled release of terbutaline sulphate. asymmetric membrane capsules contains pore-forming water soluble additive, sorbitol in different concentrations in the capsule shell membrane, which after coming in contact with water, dissolves, resulting in an in situ formation of a microporous structure. The terbutaline sulphate is a β-adrenoreceptor agonist widely used in the treatment of asthma. The oral dosage regimen of terbutaline sulphate is 5 mg twice or thrice daily, the plasma half-life is approximate 3-4 h and it produces GI irritation with extensive first pass metabolism. Hence, terbutaline sulphate was chosen as a model drug with an aim to develop controlled release system. Different formulations of ethyl cellulose were prepared by phase inversion technique using different concentrations of sorbitol as pore forming agent. It was found that the thickness of the prepared asymmetric membrane capsules was increased with increase in concentration of ethyl cellulose and pore forming agent, i.e. sorbitol. The dye release study in water and 10% sodium chloride solution indicates that, the asymmetric membrane capsules follow osmotic principle to release content. The pores formed due to sorbitol were confirmed by microscopic observation of transverse section of capsule membrane. Data of in vitro release study of terbutaline sulphate from asymmetric membrane capsules indicated that, the capsules prepared with 10% and 12.5% of ethyl cellulose and 25% of sorbitol released as much as 97.44% and 76.27% in 12 h, respectively with zero order release rate. Hence asymmetric membrane capsule of 10% ethyl cellulose and 25% of sorbitol is considered as optimum for controlled oral delivery of terbutaline sulphate. PMID:23204625

  8. Structurally altered capsular polysaccharides produced by mutant bacteria

    NASA Technical Reports Server (NTRS)

    Kern, Roger G. (Inventor); Petersen, Gene R. (Inventor); Richards, Gil F. (Inventor)

    1995-01-01

    Structurally altered capsular polysaccharides are produced by mutant bacteria. These polysaccharides are isolated by selecting a wild type bacterial strain and a phage producing degradative enzymes that have substrate specificity for the capsular polysaccharides produced by the wild type bacteria. Phage-resistant mutants producing capsular polysaccharides are selected and the structurally altered capsular polysaccharide is isolated therefrom.

  9. Campylobacter capsule and lipooligosaccharide confer resistance to serum and cationic antimicrobials

    PubMed Central

    Keo, Thormika; Collins, Jennifer; Kunwar, Pratima; Blaser, Martin J

    2011-01-01

    The innate immune system plays a critical role in host defense against mucosal bacteria. Campylobacter jejuni is a major cause of human gastroenteritis that usually resolves spontaneously within several days, suggesting that innate mechanisms are important to control the infection. However, the specific means by which this occurs is not well understood. While diarrheal isolates of C. jejuni usually are susceptible to human serum, we found that a systemic strain of C. jejuni, isolated from the cerebrospinal fluid of an infant with meningitis, is relatively more resistant to human serum, the Bactericidal/Permeability-Increasing Protein (BPI), an endogenous cationic antimicrobial protein, and the cationic peptide antibiotic polymyxin B. To test the hypothesis that the surface properties of this strain contributed to its ability to withstand these innate host defenses, we constructed isogenic mutants in capsule (kpsM) and lipooligosaccharide (waaF) and complemented these mutants by insertion of the complementation construct in trans into hipO, a chromosomal locus. We found that capsule expression was essential for serum resistance, whereas lipooligosaccharide played no substantial role. In contrast, the lipooligosaccharide mutant showed increased sensitivity to polymyxin B, α-defensins, cathelicidins and BPI. These findings suggest that the polysaccharides of C. jejuni strains contribute differently to resistance against host innate immunity, whereby capsule is more important for resisting human complement and lipooligosaccharide is more important for protection against killing mediated by cationic antimicrobial peptides and proteins. PMID:21266840

  10. Fabrication of capsule assemblies, phase 3

    NASA Technical Reports Server (NTRS)

    Keeton, A. R.; Stemann, L. G.

    1973-01-01

    Thirteen capsule assemblies were fabricated for evaluation of fuel pin design concepts for a fast spectrum lithium cooled compact space power reactor. These instrumented assemblies were designed for real time test of prototype fuel pins. Uranium mononitride fuel pins were encased in AISI 304L stainless steel capsules. Fabrication procedures were fully qualified by process development and assembly qualification tests. Instrumentation reliability was achieved utilizing specially processed and closely controlled thermocouple hot zone fabrication and by thermal screening tests. Overall capsule reliability was achieved with an all electron beam welded assembly.

  11. Sucrose release from polysaccharide gels.

    PubMed

    Nishinari, Katsuyoshi; Fang, Yapeng

    2016-05-18

    Sucrose release from polysaccharide gels has been studied extensively because it is expected to be useful in understanding flavour release from solid foods and to find a new processing method which produces more palatable and healthier foods. We provide an overview of the release of sucrose and other sugars from gels of agar and related polysaccharides. The addition of sucrose to agar solutions leads to the increase in transparency of the resulting gels and the decrease in syneresis, which is attributed to the decrease in mesh size in gels. The syneresis occurring in the quiescent condition and fluid release induced by compression is discussed. The relationship between the sugar release and the structural, rheological and thermal properties of gels is also discussed. Finally, the future research direction is proposed.

  12. Cellulose degradation by polysaccharide monooxygenases.

    PubMed

    Beeson, William T; Vu, Van V; Span, Elise A; Phillips, Christopher M; Marletta, Michael A

    2015-01-01

    Polysaccharide monooxygenases (PMOs), also known as lytic PMOs (LPMOs), enhance the depolymerization of recalcitrant polysaccharides by hydrolytic enzymes and are found in the majority of cellulolytic fungi and actinomycete bacteria. For more than a decade, PMOs were incorrectly annotated as family 61 glycoside hydrolases (GH61s) or family 33 carbohydrate-binding modules (CBM33s). PMOs have an unusual surface-exposed active site with a tightly bound Cu(II) ion that catalyzes the regioselective hydroxylation of crystalline cellulose, leading to glycosidic bond cleavage. The genomes of some cellulolytic fungi contain more than 20 genes encoding cellulose-active PMOs, suggesting a diversity of biological activities. PMOs show great promise in reducing the cost of conversion of lignocellulosic biomass to fermentable sugars; however, many questions remain about their reaction mechanism and biological function. This review addresses, in depth, the structural and mechanistic aspects of oxidative depolymerization of cellulose by PMOs and considers their biological function and phylogenetic diversity.

  13. Sucrose release from polysaccharide gels.

    PubMed

    Nishinari, Katsuyoshi; Fang, Yapeng

    2016-05-18

    Sucrose release from polysaccharide gels has been studied extensively because it is expected to be useful in understanding flavour release from solid foods and to find a new processing method which produces more palatable and healthier foods. We provide an overview of the release of sucrose and other sugars from gels of agar and related polysaccharides. The addition of sucrose to agar solutions leads to the increase in transparency of the resulting gels and the decrease in syneresis, which is attributed to the decrease in mesh size in gels. The syneresis occurring in the quiescent condition and fluid release induced by compression is discussed. The relationship between the sugar release and the structural, rheological and thermal properties of gels is also discussed. Finally, the future research direction is proposed. PMID:26952168

  14. Cellulose degradation by polysaccharide monooxygenases.

    PubMed

    Beeson, William T; Vu, Van V; Span, Elise A; Phillips, Christopher M; Marletta, Michael A

    2015-01-01

    Polysaccharide monooxygenases (PMOs), also known as lytic PMOs (LPMOs), enhance the depolymerization of recalcitrant polysaccharides by hydrolytic enzymes and are found in the majority of cellulolytic fungi and actinomycete bacteria. For more than a decade, PMOs were incorrectly annotated as family 61 glycoside hydrolases (GH61s) or family 33 carbohydrate-binding modules (CBM33s). PMOs have an unusual surface-exposed active site with a tightly bound Cu(II) ion that catalyzes the regioselective hydroxylation of crystalline cellulose, leading to glycosidic bond cleavage. The genomes of some cellulolytic fungi contain more than 20 genes encoding cellulose-active PMOs, suggesting a diversity of biological activities. PMOs show great promise in reducing the cost of conversion of lignocellulosic biomass to fermentable sugars; however, many questions remain about their reaction mechanism and biological function. This review addresses, in depth, the structural and mechanistic aspects of oxidative depolymerization of cellulose by PMOs and considers their biological function and phylogenetic diversity. PMID:25784051

  15. Required Be Capsule Strength For Room Temperature Transport

    SciTech Connect

    Cook, B

    2005-03-21

    The purpose of this memo is to lay out the criteria for the Be capsule strength necessary for room temperature transport. Ultimately we will test full thickness capsules by sealing high pressures inside, but currently we are limited to both thinner capsules and alternative measures of capsule material strength.

  16. 46 CFR 172.070 - Intact stability.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Intact stability. 172.070 Section 172.070 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES PERTAINING TO BULK CARGOES Special Rules Pertaining to a Vessel That Carries a Cargo Regulated Under 33 CFR Part...

  17. 46 CFR 172.070 - Intact stability.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Intact stability. 172.070 Section 172.070 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES PERTAINING TO BULK CARGOES Special Rules Pertaining to a Vessel That Carries a Cargo Regulated Under 33 CFR Part...

  18. 46 CFR 172.070 - Intact stability.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Intact stability. 172.070 Section 172.070 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES PERTAINING TO BULK CARGOES Special Rules Pertaining to a Vessel That Carries a Cargo Regulated Under 33 CFR Part...

  19. 46 CFR 172.070 - Intact stability.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Intact stability. 172.070 Section 172.070 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES PERTAINING TO BULK CARGOES Special Rules Pertaining to a Vessel That Carries a Cargo Regulated Under 33 CFR Part...

  20. 46 CFR 172.070 - Intact stability.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Intact stability. 172.070 Section 172.070 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES PERTAINING TO BULK CARGOES Special Rules Pertaining to a Vessel That Carries a Cargo Regulated Under 33 CFR Part...

  1. HYDROCARBON VAPOR DIFFUSION IN INTACT CORE SLEEVES

    EPA Science Inventory

    The diffusion of 2,2,4-trimethylpentane (TMP) and 2,2,5-trimethylhexane (TMH) vapors put of residually contaminated sandy soil from the U.S. Environmental Protection Agency (EPA) field research site at Traverse City, Michigan, was measured and modeled. The headspace of an intact ...

  2. Biosynthesis and assembly of cell wall polysaccharides in cereal grasses

    SciTech Connect

    Carpita, N.C.

    1991-04-01

    We have just completed the second year of a three-year project entitled Biosynthesis assembly of cell wall polysaccharides in cereal grasses.'' We made significant progress on two aspects of cell wall synthesis in grasses and greatly refined gas-liquid and high- performance liquid chromatographic techniques necessary to identify the products of synthesis in vitro and in vivo. First, Dr. David Gibeaut, a post-doctoral associate, devised a convenient procedure for the enrichment of Golgi membranes by flotation centrifugation following initial downward rate-zonal separation. Based on comparison of the IDPase marker enzyme, flotation centrifugation enriched the Golgi apparatus almost 7-fold after the initial downward separation. This system is now used in our studies of the synthesis in vitro of the mixed-linkage {beta}-D-glucan. Second, Gibeaut and I have devised a simple technique to feed radioactive sugars into intact growing seedlings and follow incorporation of radioactivity into and turnover from specific cell wall polysaccharides. The project has also provided a few spin-off projects that have been productive as well. First, in collaboration with the group of Prof. Peter Kaufman, University of Michigan, we examined changes in cell wall structure concomitant with reaction to gravistimulation in the gravisensing oat pulvinus. Second, Dr. Gibeaut developed a simple clean-up procedure for partially methylated alditol derivatives to remove a large amount of undesirable interfering compounds that confound separation of the derivatives by gas-liquid chromatography. 5 refs.

  3. 46 CFR 178.320 - Intact stability requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Intact stability requirements. 178.320 Section 178.320... TONS) INTACT STABILITY AND SEAWORTHINESS Intact Stability Standards § 178.320 Intact stability... stability proof test in accordance with § 178.330 of this part in the presence of a Coast Guard...

  4. 46 CFR 178.310 - Intact stability requirements-general.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Intact stability requirements-general. 178.310 Section... (UNDER 100 GROSS TONS) INTACT STABILITY AND SEAWORTHINESS Intact Stability Standards § 178.310 Intact stability requirements—general. (a) Except as provided in paragraph (c) of this section, each vessel...

  5. 46 CFR 178.310 - Intact stability requirements-general.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Intact stability requirements-general. 178.310 Section... (UNDER 100 GROSS TONS) INTACT STABILITY AND SEAWORTHINESS Intact Stability Standards § 178.310 Intact stability requirements—general. (a) Except as provided in paragraph (c) of this section, each vessel...

  6. 46 CFR 178.310 - Intact stability requirements-general.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Intact stability requirements-general. 178.310 Section... (UNDER 100 GROSS TONS) INTACT STABILITY AND SEAWORTHINESS Intact Stability Standards § 178.310 Intact stability requirements—general. (a) Except as provided in paragraph (c) of this section, each vessel...

  7. Does magnetically assisted capsule endoscopy improve small bowel capsule endoscopy completion rate? A randomised controlled trial

    PubMed Central

    Hale, Melissa F.; Drew, Kaye; Sidhu, Reena; McAlindon, Mark E.

    2016-01-01

    Background and study aims: Delayed gastric emptying is a significant factor in incomplete small bowel capsule examinations. Gastric transit could be hastened by external magnetic control of the capsule. We studied the feasibility of this approach to improve capsule endoscopy completion rates. Patients and methods: Prospective, single-center, randomized controlled trial involving 122 patients attending for small bowel capsule endoscopy using MiroCam Navi. Patients were randomized to either the control group (mobilisation for 30 minutes after capsule ingestion, followed by intramuscular metoclopramide 10 mg if the capsule failed to enter the small bowel) or the intervention group (1000 mL of water prior to capsule ingestion, followed by positional change and magnetic steering). Outcome measures were capsule endoscopy completion rate, gastric clarity and distention, relationship of body habitus to capsule endoscopy completion rate (CECR), and patient comfort scores. Results: 122 patients were recruited (61 each to the control and intervention groups: mean age 49 years [range 21 – 85], 61 females). There was no significant difference in CECR between the two groups (P = 0.39). Time to first pyloric image was significantly shorter in the intervention group (P = 0.03) but there was no difference in gastric transit times (P = 0.12), suggesting that magnetic control hastens capsular transit to the gastric antrum but does not influence duodenal passage. Gastric clarity and distention were significantly better in the intervention group (P < 0.0001 and P < 0.0001 respectively). Conclusions: Magnetic steering of a small bowel capsule is unable to overcome pyloric contractions to enhance gastric emptying and improve capsule endoscope completion rate. Excellent mucosal visualisation within the gastric cavity suggests this technique could be harnessed for capsule examination of the stomach. PMID:26878053

  8. Polysaccharide-Based Micelles for Drug Delivery

    PubMed Central

    Zhang, Nan; Wardwell, Patricia R.; Bader, Rebecca A.

    2013-01-01

    Delivery of hydrophobic molecules and proteins has been an issue due to poor bioavailability following administration. Thus, micelle carrier systems are being investigated to improve drug solubility and stability. Due to problems with toxicity and immunogenicity, natural polysaccharides are being explored as substitutes for synthetic polymers in the development of new micelle systems. By grafting hydrophobic moieties to the polysaccharide backbone, self-assembled micelles can be readily formed in aqueous solution. Many polysaccharides also possess inherent bioactivity that can facilitate mucoadhesion, enhanced targeting of specific tissues, and a reduction in the inflammatory response. Furthermore, the hydrophilic nature of some polysaccharides can be exploited to enhance circulatory stability. This review will highlight the advantages of polysaccharide use in the development of drug delivery systems and will provide an overview of the polysaccharide-based micelles that have been developed to date. PMID:24300453

  9. Marine Polysaccharides in Pharmaceutical Applications: An Overview

    PubMed Central

    Laurienzo, Paola

    2010-01-01

    The enormous variety of polysaccharides that can be extracted from marine plants and animal organisms or produced by marine bacteria means that the field of marine polysaccharides is constantly evolving. Recent advances in biological techniques allow high levels of polysaccharides of interest to be produced in vitro. Biotechnology is a powerful tool to obtain polysaccharides from a variety of micro-organisms, by controlling the growth conditions in a bioreactor while tailoring the production of biologically active compounds. Following an overview of the current knowledge on marine polysaccharides, with special attention to potential pharmaceutical applications and to more recent progress on the discovering of new polysaccharides with biological appealing characteristics, this review will focus on possible strategies for chemical or physical modification aimed to tailor the final properties of interest. PMID:20948899

  10. Small Particles Intact Capture Experiment (SPICE)

    NASA Technical Reports Server (NTRS)

    Nishioka, Ken-Ji; Carle, G. C.; Bunch, T. E.; Mendez, David J.; Ryder, J. T.

    1994-01-01

    The Small Particles Intact Capture Experiment (SPICE) will develop technologies and engineering techniques necessary to capture nearly intact, uncontaminated cosmic and interplanetary dust particles (IDP's). Successful capture of such particles will benefit the exobiology and planetary science communities by providing particulate samples that may have survived unaltered since the formation of the solar system. Characterization of these particles may contribute fundamental data to our knowledge of how these particles could have formed into our planet Earth and, perhaps, contributed to the beginnings of life. The term 'uncontaminated' means that captured cosmic and IDP particles are free of organic contamination from the capture process and the term 'nearly intact capture' means that their chemical and elemental components are not materially altered during capture. The key to capturing cosmic and IDP particles that are organic-contamination free and nearly intact is the capture medium. Initial screening of capture media included organic foams, multiple thin foil layers, and aerogel (a silica gel); but, with the exception of aerogel, the requirements of no contamination or nearly intact capture were not met. To ensure no contamination of particles in the capture process, high-purity aerogel was chosen. High-purity aerogel results in high clarity (visual clearness), a useful quality in detection and recovery of embedded captured particles from the aerogel. P. Tsou at the Jet Propulsion Laboratory (JPL) originally described the use of aerogel for this purpose and reported laboratory test results. He has flown aerogel as a 'GAS-can Lid' payload on STS-47 and is evaluating the results. The Timeband Capture Cell Experiment (TICCE), a Eureca 1 experiment, is also flying aerogel and is scheduled for recovery in late April.

  11. Polysaccharide-based nanocomposites and their applications

    PubMed Central

    Zheng, Yingying; Monty, Jonathan; Linhardt, Robert J.

    2014-01-01

    Polysaccharide nanocomposites have become increasingly important materials over the past decade. Polysaccharides offer a green alternative to synthetic polymers in the preparation of soft nanomaterials. They have also been used in composites with hard nanomaterials, such as metal nanoparticles and carbon-based nanomaterials. This mini review describes methods for polysaccharide nanocomposite preparation and reviews the various types and diverse applications for these novel materials. PMID:25498200

  12. Identification of Bacillus anthracis by using monoclonal antibody to cell wall galactose-N-acetylglucosamine polysaccharide.

    PubMed Central

    Ezzell, J W; Abshire, T G; Little, S F; Lidgerding, B C; Brown, C

    1990-01-01

    Guanidine extracts of crude Bacillus anthracis cell wall were used to vaccinate BALB/c mice and to develop monoclonal antibody (MAb) to vegetative cell surface antigens. Two hybridomas selected during this study produced immunoglobulin M immunoglobulins, which appear to be directed to an epitope associated with the galactose-N-acetyl-D-glucosamine polysaccharide. Both demonstrated specificity in their binding to purified B. anthracis cell wall, o-stearoyl-polysaccharide conjugates, and intact, nonencapsulated vegetative cells. The interaction of the MAbs with purified polysaccharide was inhibited by 0.5 M galactose and lactose but not by N-acetylglucosamine, glutamate, glycine, or glycerol. Inhibition by glucose or sucrose was approximately 75% of that seen with galactose. Electron microscopy showed that both MAbs interacted with the cell wall of vegetative cells as well as with the cortex of spores. Neither MAb reacted with encapsulated vegetative cells, such as those from infected guinea pigs, nor did they react with intact spores. After conjugation to fluorescein isothiocyanate, the MAbs stained intensely all B. anthracis strains tested, whereas with two exceptions, none of the strains of 20 other Bacillus spp. was stained. The exceptions, strains of Bacillus cereus, could be differentiated from B. anthracis by being beta-hemolytic on blood agar. Images PMID:2107201

  13. [Pathogenesis of posterior capsule opacification in pseudophakia].

    PubMed

    Łukaszewska-Smyk, Agnieszka; Kałuzny, Józef

    2009-01-01

    The lens epithelial cells of A and E type are involved in pathogenesis of posterior capsule opacification (PCO). They undergo metaplasia into microfibroblasts, then migrate towards posterior capsule where they proliferate and form opacification. These processes are stimulated by cytokines and interleukines. The extracellular matrix which constitutes a scaffold for migration and attachment of epithelial cells plays an important role in PCO formation. Integrines intercede in this process.

  14. Advances on Bioactive Polysaccharides from Medicinal Plants.

    PubMed

    Xie, Jian-Hua; Jin, Ming-Liang; Morris, Gordon A; Zha, Xue-Qiang; Chen, Han-Qing; Yi, Yang; Li, Jing-En; Wang, Zhi-Jun; Gao, Jie; Nie, Shao-Ping; Shang, Peng; Xie, Ming-Yong

    2016-07-29

    In recent decades, the polysaccharides from the medicinal plants have attracted a lot of attention due to their significant bioactivities, such as anti-tumor activity, antioxidant activity, anticoagulant activity, antidiabetic activity, radioprotection effect, anti-viral activity, hypolipidemic and immunomodulatory activities, which make them suitable for medicinal applications. Previous studies have also shown that medicinal plant polysaccharides are non-toxic and show no side effects. Based on these encouraging observations, most researches have been focusing on the isolation and identification of polysaccharides, as well as their bioactivities. A large number of bioactive polysaccharides with different structural features and biological effects from medicinal plants have been purified and characterized. This review provides a comprehensive summary of the most recent developments in physiochemical, structural features and biological activities of bioactive polysaccharides from a number of important medicinal plants, such as polysaccharides from Astragalus membranaceus, Dendrobium plants, Bupleurum, Cactus fruits, Acanthopanax senticosus, Angelica sinensis (Oliv.) Diels, Aloe barbadensis Miller, and Dimocarpus longan Lour. Moreover, the paper has also been focused on the applications of bioactive polysaccharides for medicinal applications. Recent studies have provided evidence that polysaccharides from medicinal plants can play a vital role in bioactivities. The contents and data will serve as a useful reference material for further investigation, production, and application of these polysaccharides in functional foods and therapeutic agents.

  15. Advances on Bioactive Polysaccharides from Medicinal Plants.

    PubMed

    Xie, Jian-Hua; Jin, Ming-Liang; Morris, Gordon A; Zha, Xue-Qiang; Chen, Han-Qing; Yi, Yang; Li, Jing-En; Wang, Zhi-Jun; Gao, Jie; Nie, Shao-Ping; Shang, Peng; Xie, Ming-Yong

    2016-07-29

    In recent decades, the polysaccharides from the medicinal plants have attracted a lot of attention due to their significant bioactivities, such as anti-tumor activity, antioxidant activity, anticoagulant activity, antidiabetic activity, radioprotection effect, anti-viral activity, hypolipidemic and immunomodulatory activities, which make them suitable for medicinal applications. Previous studies have also shown that medicinal plant polysaccharides are non-toxic and show no side effects. Based on these encouraging observations, most researches have been focusing on the isolation and identification of polysaccharides, as well as their bioactivities. A large number of bioactive polysaccharides with different structural features and biological effects from medicinal plants have been purified and characterized. This review provides a comprehensive summary of the most recent developments in physiochemical, structural features and biological activities of bioactive polysaccharides from a number of important medicinal plants, such as polysaccharides from Astragalus membranaceus, Dendrobium plants, Bupleurum, Cactus fruits, Acanthopanax senticosus, Angelica sinensis (Oliv.) Diels, Aloe barbadensis Miller, and Dimocarpus longan Lour. Moreover, the paper has also been focused on the applications of bioactive polysaccharides for medicinal applications. Recent studies have provided evidence that polysaccharides from medicinal plants can play a vital role in bioactivities. The contents and data will serve as a useful reference material for further investigation, production, and application of these polysaccharides in functional foods and therapeutic agents. PMID:26463231

  16. Towards Polymer-Based Capsules with Drastically Reduced Controlled Permeability

    NASA Astrophysics Data System (ADS)

    Andreeva, Daria V.; Sukhorukov, Gleb B.

    Small molecules (dyes, therapeutics, etc.) could be easily handled, stored, delivered, and released by polyelectrolyte capsules. To make the polyelectrolyte capsule more efficient for small molecule encapsulation, capsule permeability should be significantly decreased. Here, we demonstrate the possibility to entrap water-soluble molecular species into polyelectrolyte capsules modified by a low permeable dense polymer (polypyrrole). Possible future areas in PE capsule application as carriers for gases and volatiles in the pharmaceutical, food, and gases industry, agriculture and cosmetology are discussed.

  17. Video capsule endoscopy in inflammatory bowel disease.

    PubMed

    Collins, Paul D

    2016-07-25

    Video capsule endoscopy (VCE) has evolved to become an important tool for the non-invasive examination of the small bowel, which hitherto had been relatively inaccessible to direct visualisation. VCE has been shown to play a role in monitoring the activity of small bowel Crohn's disease and can be used to assess the response to anti-inflammatory treatment in Crohn's disease. For those patients with Crohn's disease who have undergone an intestinal resection, VCE has been assessed as a tool to detect post-operative recurrence. VCE may also aid in the reclassification of patients with a diagnosis of Inflammatory Bowel Disease Unclassified to Crohn's disease. The evolution of colon capsule endoscopy (CCE) has expanded the application of this technology further. The use of CCE to assess the activity of ulcerative colitis has been described. This advance in capsule technology has also fuelled interest in its potential role as a minimally invasive tool to assess the whole of GI tract opening the possibility of its use for the panenteric assessment of Crohn's disease. VCE is a safe procedure. However, the risk of a retained capsule is higher in patients with suspected or confirmed Crohn's disease compared with patients having VCE examination for other indications. A retained video capsule is rare after successful passage of a patency capsule which may be utilised to pre-screen patients undergoing VCE. This paper describes the use of VCE in the assessment of inflammatory bowel disease. PMID:27499830

  18. Light weight escape capsule for fighter aircraft

    NASA Technical Reports Server (NTRS)

    Robert, James A.

    1988-01-01

    Emergency crew escape capabilities have been less than adequate for fighter aircraft since before WW II. From the over-the-side bailout of those days through the current ejection seat with a rocket catapult, escaping from a disabled aircraft has been risky at best. Current efforts are underway toward developing a high-tech, smart ejection seat that will give fighter pilots more room to live in the sky, but an escape capsule is needed to meet current and future fighter envelopes. Escape capsules have a bad reputation due to past examples of high weight, poor performance and great complexity. However, the advantages available demand that a capsule be developed. This capsule concept will minimize the inherent disavantages and incorporate the benefits while integrating all aspects of crew station design. The resulting design is appropriate for a crew station of the year 2010 and includes improved combat acceleration protection, chemical or biological combat capability, improved aircraft to escape system interaction, and the highest level of escape performance achievable. The capsule is compact, which can allow a reduced aircraft size and weighs only 1200 lb. The escape system weight penalty is only 120 lb higher than that for the next ejection seat and the capsule has a corresponding increase in performance.

  19. Structure, biosynthesis, and function of bacterial capsular polysaccharides synthesized by ABC transporter-dependent pathways.

    PubMed

    Willis, Lisa M; Whitfield, Chris

    2013-08-30

    Bacterial capsules are formed primarily from long-chain polysaccharides with repeat-unit structures. A given bacterial species can produce a range of capsular polysaccharides (CPSs) with different structures and these help distinguish isolates by serotyping, as is the case with Escherichia coli K antigens. Capsules are important virulence factors for many pathogens and this review focuses on CPSs synthesized via ATP-binding cassette (ABC) transporter-dependent processes in Gram-negative bacteria. Bacteria utilizing this pathway are often associated with urinary tract infections, septicemia, and meningitis, and E. coli and Neisseria meningitidis provide well-studied examples. CPSs from ABC transporter-dependent pathways are synthesized at the cytoplasmic face of the inner membrane through the concerted action of glycosyltransferases before being exported across the inner membrane and translocated to the cell surface. A hallmark of these CPSs is a conserved reducing terminal glycolipid composed of phosphatidylglycerol and a poly-3-deoxy-d-manno-oct-2-ulosonic acid (Kdo) linker. Recent discovery of the structure of this conserved lipid terminus provides new insights into the early steps in CPS biosynthesis.

  20. Silver polyvinyl pyrrolidone nanoparticles exhibit a capsular polysaccharide influenced bactericidal effect against Streptococcus pneumoniae

    PubMed Central

    Bibbs, Ronda K.; Harris, Rhonda D.; Peoples, Veolanda A.; Barnett, Cleon; Singh, Shree R.; Dennis, Vida A.; Coats, Mamie T.

    2014-01-01

    Streptococcus pneumoniae remains a leading cause of morbidity and mortality worldwide. The highly adaptive nature of S. pneumoniae exemplifies the need for next generation antimicrobials designed to avoid high level resistance. Metal based nanomaterials fit this criterion. Our study examined the antimicrobial activity of gold nanospheres, silver coated polyvinyl pyrrolidone (AgPVP), and titanium dioxide (TiO2) against various serotypes of S. pneumoniae. Twenty nanometer spherical AgPVP demonstrated the highest level of killing among the tested materials. AgPVP (0.6 mg/mL) was able to kill pneumococcal serotypes 2, 3, 4, and 19F within 4 h of exposure. Detailed analysis of cultures during exposure to AgPVP showed that both the metal ions and the solid nanoparticles participate in the killing of the pneumococcus. The bactericidal effect of AgPVP was lessened in the absence of the pneumococcal capsular polysaccharide. Capsule negative strains, JD908 and RX1, were only susceptible to AgPVP at concentrations at least 33% higher than their respective capsule expressing counterparts. These findings suggest that mechanisms of killing used by nanomaterials are not serotype dependent and that the capsular polysaccharide participates in the inhibition. In the near future these mechanisms will be examined as targets for novel antimicrobials. PMID:25520713

  1. Endotoxin, capsule, and bacterial attachment contribute to Neisseria meningitidis resistance to the human antimicrobial peptide LL-37.

    PubMed

    Jones, Allison; Geörg, Miriam; Maudsdotter, Lisa; Jonsson, Ann-Beth

    2009-06-01

    Pathogenic bacteria have evolved numerous mechanisms to evade the human immune system and have developed widespread resistance to traditional antibiotics. We studied the human pathogen Neisseria meningitidis and present evidence of novel mechanisms of resistance to the human antimicrobial peptide LL-37. We found that bacteria attached to host epithelial cells are resistant to 10 microM LL-37 whereas bacteria in solution or attached to plastic are killed, indicating that the cell microenvironment protects bacteria. The bacterial endotoxin lipooligosaccharide and the polysaccharide capsule contribute to LL-37 resistance, probably by preventing LL-37 from reaching the bacterial membrane, as more LL-37 reaches the bacterial membrane on both lipooligosaccharide-deficient and capsule-deficient mutants whereas both mutants are also more susceptible to LL-37 killing than the wild-type strain. N. meningitidis bacteria respond to sublethal doses of LL-37 and upregulate two of their capsule genes, siaC and siaD, which further results in upregulation of capsule biosynthesis.

  2. The ESX-5 System of Pathogenic Mycobacteria Is Involved In Capsule Integrity and Virulence through Its Substrate PPE10

    PubMed Central

    Ates, Louis S.; van der Woude, Aniek D.; Bestebroer, Jovanka; van Stempvoort, Gunny; Musters, René J. P.; Garcia-Vallejo, Juan J.; Picavet, Daisy I.; van de Weerd, Robert; Maletta, Massimiliano; Kuijl, Coenraad P.; van der Wel, Nicole N.; Bitter, Wilbert

    2016-01-01

    Mycobacteria produce a capsule layer, which consists of glycan-like polysaccharides and a number of specific proteins. In this study, we show that, in slow-growing mycobacteria, the type VII secretion system ESX-5 plays a major role in the integrity and stability of the capsule. We have identified PPE10 as the ESX-5 substrate responsible for this effect. Mutants in esx-5 and ppe10 both have impaired capsule integrity as well as reduced surface hydrophobicity. Electron microscopy, immunoblot and flow cytometry analyses demonstrated reduced amounts of surface localized proteins and glycolipids, and morphological differences in the capsular layer. Since capsular proteins secreted by the ESX-1 system are important virulence factors, we tested the effect of the mutations that cause capsular defects on virulence mechanisms. Both esx-5 and ppe10 mutants of Mycobacterium marinum were shown to be impaired in ESX-1-dependent hemolysis. In agreement with this, the ppe10 and esx5 mutants showed reduced recruitment of ubiquitin in early macrophage infection and intermediate attenuation in zebrafish embryos. These results provide a pivotal role for the ESX-5 secretion system and its substrate PPE10, in the capsular integrity of pathogenic mycobacteria. These findings open up new roads for research on the mycobacterial capsule and its role in virulence and immune modulation. PMID:27280885

  3. A major role for capsule-independent phagocytosis-inhibitory mechanisms in mammalian infection by Cryptococcus neoformans

    PubMed Central

    Chun, Cheryl D.; Brown, Jessica C. S.; Madhani, Hiten D.

    2011-01-01

    Summary The anti-phagocytic polysaccharide capsule of the human fungal pathogen Cryptococcus neoformans is a major virulence attribute. However, previous studies of the pleiotropic virulence determinant Gat201, a GATA-family transcription factor, suggested that capsule-independent antiphagocytic mechanisms exist. We have determined that Gat201 controls the mRNA levels of ~1100 genes (16% of the genome) and binds the upstream regions of ~130 genes. Seven Gat201-bound genes encode for putative and known transcription factors—including two previously implicated in virulence—suggesting an extensive regulatory network. Systematic analysis pinpointed two critical Gat201-bound genes, GAT204 (a transcription factor) and BLP1, which account for much of the capsule-independent antiphagocytic function of Gat201. A strong correlation was observed between the quantitative effects of single and double mutants on phagocytosis in vitro and on host colonization in vivo. This genetic dissection provides evidence that capsule-independent anti-phagocytic mechanisms are pivotal for successful mammalian infection by C. neoformans. PMID:21402362

  4. Extensive Capsule Locus Variation and Large-Scale Genomic Recombination within the Klebsiella pneumoniae Clonal Group 258

    PubMed Central

    Wyres, Kelly L.; Gorrie, Claire; Edwards, David J.; Wertheim, Heiman F.L.; Hsu, Li Yang; Van Kinh, Nguyen; Zadoks, Ruth; Baker, Stephen; Holt, Kathryn E.

    2015-01-01

    Klebsiella pneumoniae clonal group (CG) 258, comprising sequence types (STs) 258, 11, and closely related variants, is associated with dissemination of the K. pneumoniae carbapenemase (KPC). Hospital outbreaks of KPC CG258 infections have been observed globally and are very difficult to treat. As a consequence, there is renewed interest in alternative infection control measures such as vaccines and phage or depolymerase treatments targeting the K. pneumoniae polysaccharide capsule. To date, 78 immunologically distinct capsule variants have been described in K. pneumoniae. Previous investigations of ST258 and a small number of closely related strains suggested that capsular variation was limited within this clone; only two distinct ST258 capsule polysaccharide synthesis (cps) loci have been identified, both acquired through large-scale recombination events (>50 kb). In contrast to previous studies, we report a comparative genomic analysis of the broader K. pneumoniae CG258 (n = 39). We identified 11 different cps loci within CG258, indicating that capsular switching is actually common within the complex. We observed several insertion sequences (IS) within the cps loci, and show further intraclone diversification of two cps loci through IS activity. Our data also indicate that several large-scale recombination events have shaped the genomes of CG258, and that definition of the complex should be broadened to include ST395 (also reported to harbor KPC). As only the second report of extensive intraclonal cps variation among Gram-negative bacterial species, our findings alter our understanding of the evolution of these organisms and have key implications for the design of control measures targeting K. pneumoniae capsules. PMID:25861820

  5. Extensive Capsule Locus Variation and Large-Scale Genomic Recombination within the Klebsiella pneumoniae Clonal Group 258.

    PubMed

    Wyres, Kelly L; Gorrie, Claire; Edwards, David J; Wertheim, Heiman F L; Hsu, Li Yang; Van Kinh, Nguyen; Zadoks, Ruth; Baker, Stephen; Holt, Kathryn E

    2015-05-01

    Klebsiella pneumoniae clonal group (CG) 258, comprising sequence types (STs) 258, 11, and closely related variants, is associated with dissemination of the K. pneumoniae carbapenemase (KPC). Hospital outbreaks of KPC CG258 infections have been observed globally and are very difficult to treat. As a consequence, there is renewed interest in alternative infection control measures such as vaccines and phage or depolymerase treatments targeting the K. pneumoniae polysaccharide capsule. To date, 78 immunologically distinct capsule variants have been described in K. pneumoniae. Previous investigations of ST258 and a small number of closely related strains suggested that capsular variation was limited within this clone; only two distinct ST258 capsule polysaccharide synthesis (cps) loci have been identified, both acquired through large-scale recombination events (>50 kb). In contrast to previous studies, we report a comparative genomic analysis of the broader K. pneumoniae CG258 (n = 39). We identified 11 different cps loci within CG258, indicating that capsular switching is actually common within the complex. We observed several insertion sequences (IS) within the cps loci, and show further intraclone diversification of two cps loci through IS activity. Our data also indicate that several large-scale recombination events have shaped the genomes of CG258, and that definition of the complex should be broadened to include ST395 (also reported to harbor KPC). As only the second report of extensive intraclonal cps variation among Gram-negative bacterial species, our findings alter our understanding of the evolution of these organisms and have key implications for the design of control measures targeting K. pneumoniae capsules. PMID:25861820

  6. Identification and characterization of a DNA region involved in the export of capsular polysaccharide by Actinobacillus pleuropneumoniae serotype 5a.

    PubMed Central

    Ward, C K; Inzana, T J

    1997-01-01

    Actinobacillus pleuropneumoniae synthesizes a serotype-specific capsular polysaccharide that acts as a protective barrier to phagocytosis and complement-mediated killing. To begin understanding the role of A. pleuropneumoniae capsule in virulence, we sought to identify the genes involved in capsular polysaccharide export and biosynthesis. A 5.3-kb XbaI fragment of A. pleuropneumoniae serotype 5a J45 genomic DNA that hybridized with DNA probes specific for the Haemophilus influenzae type b cap export region was cloned and sequenced. This A. pleuropneumoniae DNA fragment encoded four open reading frames, designated cpxDCBA. The nucleotide and predicted amino acid sequences of cpxDCBA contained a high degree of homology to the capsule export genes of H. influenzae type b bexDCBA, Neisseria meningitidis group B ctrABCD, and, to a lesser extent, Escherichia coli K1 and K5 kpsE and kpsMT. When present in trans, the cpxDCBA gene cluster complemented kpsM::TnphoA or kpsT::TnphoA mutations, determined by enzyme immunoassay and by restored sensitivity to a K5-specific bacteriophage. A cpxCB probe hybridized to genomic DNA from all A. pleuropneumoniae serotypes tested, indicating that this DNA was conserved among serotypes. These data suggest that A. pleuropneumoniae produces a group II family capsule similar to those of related mucosal pathogens. PMID:9169799

  7. Multidimensional solid-state NMR studies of the structure and dynamics of pectic polysaccharides in uniformly 13C-labeled Arabidopsis primary cell walls

    SciTech Connect

    Dick-Perez, Marilu; Wang, Tuo; Salazar, Andre; Zabotina, Olga A.; Hong, Mei

    2012-07-08

    Plant cell wall (CW) polysaccharides are responsible for the mechanical strength and growth of plant cells; however, the high-resolution structure and dynamics of the CW polysaccharides are still poorly understood because of the insoluble nature of these molecules. Here, we use 2D and 3D magic-angle-spinning (MAS) solid-state NMR (SSNMR) to investigate the structural role of pectins in the plant CW. Intact and partially depectinated primary CWs of Arabidopsis thaliana were uniformly labeled with 13C and their NMR spectra were compared. Recent 13C resonance assignment of the major polysaccharides in Arabidopsis thaliana CWs allowed us to determine the effects of depectination on the intermolecular packing and dynamics of the remaining wall polysaccharides. 2D and 3D correlation spectra show the suppression of pectin signals, confirming partial pectin removal by chelating agents and sodium carbonate. Importantly, higher cross peaks are observed in 2D and 3D 13C spectra of the depectinated CW, suggesting higher rigidity and denser packing of the remaining wall polysaccharides compared with the intact CW. 13C spin–lattice relaxation times and 1H rotating-frame spin–lattice relaxation times indicate that the polysaccharides are more rigid on both the nanosecond and microsecond timescales in the depectinated CW. Taken together, these results indicate that pectic polysaccharides are highly dynamic and endow the polysaccharide network of the primary CW with mobility and flexibility, which may be important for pectin functions. This study demonstrates the capability of multidimensional SSNMR to determine the intermolecular interactions and dynamic structures of complex plant materials under near-native conditions. Copyright © 2012 John Wiley & Sons, Ltd.

  8. Xenopus egg cytoplasm with intact actin.

    PubMed

    Field, Christine M; Nguyen, Phuong A; Ishihara, Keisuke; Groen, Aaron C; Mitchison, Timothy J

    2014-01-01

    We report optimized methods for preparing Xenopus egg extracts without cytochalasin D, that we term "actin-intact egg extract." These are undiluted egg cytoplasm that contains abundant organelles, and glycogen which supplies energy, and represents the least perturbed cell-free cytoplasm preparation we know of. We used this system to probe cell cycle regulation of actin and myosin-II dynamics (Field et al., 2011), and to reconstitute the large, interphase asters that organize early Xenopus embryos (Mitchison et al., 2012; Wühr, Tan, Parker, Detrich, & Mitchison, 2010). Actin-intact Xenopus egg extracts are useful for analysis of actin dynamics, and interaction of actin with other cytoplasmic systems, in a cell-free system that closely mimics egg physiology, and more generally for probing the biochemistry and biophysics of the egg, zygote, and early embryo. Detailed protocols are provided along with assays used to check cell cycle state and tips for handling and storing undiluted egg extracts.

  9. Silica Aerogel Captures Cosmic Dust Intact

    NASA Technical Reports Server (NTRS)

    Tsou, P.

    1994-01-01

    The mesostructure of silica aerogel resembles stings of grapes, ranging in size from 10 to 100 angstrom. This fine mesostructure transmits nearly 90 percent of incident light in the visible, while providing sufficiently gentle dissipation of the kinetric energy of hypervelocity cosmic dust particles to permit their intact capture. We introduced silica aerogel in 1987 as capture medium to take advantage of its low density, fine mesostruicture and most importantly, its transparency, allowing optical location of captured micron sized particles.

  10. Measuring mitochondrial function in intact cardiac myocytes

    PubMed Central

    Dedkova, Elena N.; Blatter, Lothar A.

    2011-01-01

    Mitochondria are involved in cellular functions that go beyond the traditional role of these organelles as the power plants of the cell. Mitochondria have been implicated in several human diseases, including cardiac dysfunction, and play a role in the aging process. Many aspects of our knowledge of mitochondria stem from studies performed on the isolated organelle. Their relative inaccessibility imposes experimental difficulties to study mitochondria in their natural environment – the cytosol of intact cells – and has hampered a comprehensive understanding of the plethora of mitochondrial functions. Here we review currently available methods to study mitochondrial function in intact cardiomyocytes. These methods primarily use different flavors of fluorescent dyes and genetically encoded fluorescent proteins in conjunction with high-resolution imaging techniques. We review methods to study mitochondrial morphology, mitochondrial membrane potential, Ca2+ and Na+ signaling, mitochondrial pH regulation, redox state and ROS production, NO signaling, oxygen consumption, ATP generation and the activity of the mitochondrial permeability transition pore. Where appropriate we complement this review on intact myocytes with seminal studies that were performed on isolated mitochondria, permeabilized cells, and in whole hearts. PMID:21964191

  11. Radioimmunoassay for intact Gross mouse leukemia virus.

    PubMed Central

    Yalow, R S; Gross, L

    1976-01-01

    A radioimmunoassay for intact Gross leukemia virus has been developed using 125I-labeled Gross virus grown in tissue culture and guinea pig antisera to Gross virus grown either in tissue culture or harvested from leukemic C3H(f) mice. Separation of bound from free labeled virus was effected using the double antibody method. The assay can detect fewer than 10(8) virus particles and has been used to measure the viral content of individual organs from inoculated leukemic C3H(f) mice and from Ak mice with spontaneous leukemia. Organs from noninoculated healthy C3H(f) mice crossreacted poorly in the system, virus generally being detectable only in the thymus and spleen and at low concentration. In some of the inoculated C3H(f) leukemic mice the viral content of as little as 0.5 mul of plasma is measurable. That this assay is for intact virus and not for soluble antigens of the viral envelope was proven by the observation that the immunoreactive material of plasma and extracts from thymus and liver of leukemic mice has a buoyant denisty in sucrose of 1.17-1.18 g/ml, corresponding to that of intact virus grown in tissue culture. With this sensitivity it may now be possible to quantitate viral concentrations in tissue and body fluids from the time of inoculation through the development of obvious pathology. PMID:1066697

  12. Multi-View Intact Space Learning.

    PubMed

    Xu, Chang; Tao, Dacheng; Xu, Chao

    2015-12-01

    It is practical to assume that an individual view is unlikely to be sufficient for effective multi-view learning. Therefore, integration of multi-view information is both valuable and necessary. In this paper, we propose the Multi-view Intact Space Learning (MISL) algorithm, which integrates the encoded complementary information in multiple views to discover a latent intact representation of the data. Even though each view on its own is insufficient, we show theoretically that by combing multiple views we can obtain abundant information for latent intact space learning. Employing the Cauchy loss (a technique used in statistical learning) as the error measurement strengthens robustness to outliers. We propose a new definition of multi-view stability and then derive the generalization error bound based on multi-view stability and Rademacher complexity, and show that the complementarity between multiple views is beneficial for the stability and generalization. MISL is efficiently optimized using a novel Iteratively Reweight Residuals (IRR) technique, whose convergence is theoretically analyzed. Experiments on synthetic data and real-world datasets demonstrate that MISL is an effective and promising algorithm for practical applications. PMID:26539856

  13. 3D Printed Programmable Release Capsules.

    PubMed

    Gupta, Maneesh K; Meng, Fanben; Johnson, Blake N; Kong, Yong Lin; Tian, Limei; Yeh, Yao-Wen; Masters, Nina; Singamaneni, Srikanth; McAlpine, Michael C

    2015-08-12

    The development of methods for achieving precise spatiotemporal control over chemical and biomolecular gradients could enable significant advances in areas such as synthetic tissue engineering, biotic-abiotic interfaces, and bionanotechnology. Living organisms guide tissue development through highly orchestrated gradients of biomolecules that direct cell growth, migration, and differentiation. While numerous methods have been developed to manipulate and implement biomolecular gradients, integrating gradients into multiplexed, three-dimensional (3D) matrices remains a critical challenge. Here we present a method to 3D print stimuli-responsive core/shell capsules for programmable release of multiplexed gradients within hydrogel matrices. These capsules are composed of an aqueous core, which can be formulated to maintain the activity of payload biomolecules, and a poly(lactic-co-glycolic) acid (PLGA, an FDA approved polymer) shell. Importantly, the shell can be loaded with plasmonic gold nanorods (AuNRs), which permits selective rupturing of the capsule when irradiated with a laser wavelength specifically determined by the lengths of the nanorods. This precise control over space, time, and selectivity allows for the ability to pattern 2D and 3D multiplexed arrays of enzyme-loaded capsules along with tunable laser-triggered rupture and release of active enzymes into a hydrogel ambient. The advantages of this 3D printing-based method include (1) highly monodisperse capsules, (2) efficient encapsulation of biomolecular payloads, (3) precise spatial patterning of capsule arrays, (4) "on the fly" programmable reconfiguration of gradients, and (5) versatility for incorporation in hierarchical architectures. Indeed, 3D printing of programmable release capsules may represent a powerful new tool to enable spatiotemporal control over biomolecular gradients. PMID:26042472

  14. 3D Printed Programmable Release Capsules

    PubMed Central

    Gupta, Maneesh K.; Meng, Fanben; Johnson, Blake N.; Kong, Yong Lin; Tian, Limei; Yeh, Yao-Wen; Masters, Nina; Singamaneni, Srikanth; McAlpine, Michael C.

    2015-01-01

    The development of methods for achieving precise spatiotemporal control over chemical and biomolecular gradients could enable significant advances in areas such as synthetic tissue engineering, biotic–abiotic interfaces, and bionanotechnology. Living organisms guide tissue development through highly orchestrated gradients of biomolecules that direct cell growth, migration, and differentiation. While numerous methods have been developed to manipulate and implement biomolecular gradients, integrating gradients into multiplexed, three-dimensional (3D) matrices remains a critical challenge. Here we present a method to 3D print stimuli-responsive core/shell capsules for programmable release of multiplexed gradients within hydrogel matrices. These capsules are composed of an aqueous core, which can be formulated to maintain the activity of payload biomolecules, and a poly(lactic-co-glycolic) acid (PLGA, an FDA approved polymer) shell. Importantly, the shell can be loaded with plasmonic gold nanorods (AuNRs), which permits selective rupturing of the capsule when irradiated with a laser wavelength specifically determined by the lengths of the nanorods. This precise control over space, time, and selectivity allows for the ability to pattern 2D and 3D multiplexed arrays of enzyme-loaded capsules along with tunable laser-triggered rupture and release of active enzymes into a hydrogel ambient. The advantages of this 3D printing-based method include (1) highly monodisperse capsules, (2) efficient encapsulation of biomolecular payloads, (3) precise spatial patterning of capsule arrays, (4) “on the fly” programmable reconfiguration of gradients, and (5) versatility for incorporation in hierarchical architectures. Indeed, 3D printing of programmable release capsules may represent a powerful new tool to enable spatiotemporal control over biomolecular gradients. PMID:26042472

  15. 3D Printed Programmable Release Capsules.

    PubMed

    Gupta, Maneesh K; Meng, Fanben; Johnson, Blake N; Kong, Yong Lin; Tian, Limei; Yeh, Yao-Wen; Masters, Nina; Singamaneni, Srikanth; McAlpine, Michael C

    2015-08-12

    The development of methods for achieving precise spatiotemporal control over chemical and biomolecular gradients could enable significant advances in areas such as synthetic tissue engineering, biotic-abiotic interfaces, and bionanotechnology. Living organisms guide tissue development through highly orchestrated gradients of biomolecules that direct cell growth, migration, and differentiation. While numerous methods have been developed to manipulate and implement biomolecular gradients, integrating gradients into multiplexed, three-dimensional (3D) matrices remains a critical challenge. Here we present a method to 3D print stimuli-responsive core/shell capsules for programmable release of multiplexed gradients within hydrogel matrices. These capsules are composed of an aqueous core, which can be formulated to maintain the activity of payload biomolecules, and a poly(lactic-co-glycolic) acid (PLGA, an FDA approved polymer) shell. Importantly, the shell can be loaded with plasmonic gold nanorods (AuNRs), which permits selective rupturing of the capsule when irradiated with a laser wavelength specifically determined by the lengths of the nanorods. This precise control over space, time, and selectivity allows for the ability to pattern 2D and 3D multiplexed arrays of enzyme-loaded capsules along with tunable laser-triggered rupture and release of active enzymes into a hydrogel ambient. The advantages of this 3D printing-based method include (1) highly monodisperse capsules, (2) efficient encapsulation of biomolecular payloads, (3) precise spatial patterning of capsule arrays, (4) "on the fly" programmable reconfiguration of gradients, and (5) versatility for incorporation in hierarchical architectures. Indeed, 3D printing of programmable release capsules may represent a powerful new tool to enable spatiotemporal control over biomolecular gradients.

  16. Starch-degrading polysaccharide monooxygenases.

    PubMed

    Vu, Van V; Marletta, Michael A

    2016-07-01

    Polysaccharide degradation by hydrolytic enzymes glycoside hydrolases (GHs) is well known. More recently, polysaccharide monooxygenases (PMOs, also known as lytic PMOs or LPMOs) were found to oxidatively degrade various polysaccharides via a copper-dependent hydroxylation. PMOs were previously thought to be either GHs or carbohydrate binding modules (CBMs), and have been re-classified in carbohydrate active enzymes (CAZY) database as auxiliary activity (AA) families. These enzymes include cellulose-active fungal PMOs (AA9, formerly GH61), chitin- and cellulose-active bacterial PMOs (AA10, formerly CBM33), and chitin-active fungal PMOs (AA11). These PMOs significantly boost the activity of GHs under industrially relevant conditions, and thus have great potential in the biomass-based biofuel industry. PMOs that act on starch are the latest PMOs discovered (AA13), which has expanded our perspectives in PMOs studies and starch degradation. Starch-active PMOs have many common structural features and biochemical properties of the PMO superfamily, yet differ from other PMO families in several important aspects. These differences likely correlate, at least in part, to the differences in primary and higher order structures of starch and cellulose, and chitin. In this review we will discuss the discovery, structural features, biochemical and biophysical properties, and possible biological functions of starch-active PMOs, as well as their potential application in the biofuel, food, and other starch-based industries. Important questions regarding various aspects of starch-active PMOs and possible economical driving force for their future studies will also be highlighted. PMID:27170366

  17. Solution NMR spectroscopy of food polysaccharides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many polysaccharides are allowed for direct food use, where they serve a number of useful functions. In addition to possibly being a source of calories, a food polysaccharide may be a dietary fiber, bulking agent, crystallization inhibitor, thickener, encapsulant, gelling agent, foam and emulsion s...

  18. Bioactive polysaccharides and gut microbiome (abstract)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many polysaccharides have shown the ability to reduce plasma cholesterol or postprandial glycemia. Viscosity in the small intestine seems to be required to slow glucose uptake. Cereal mixed linkage beta-glucans, psyllium, glucomannans, and other polysaccharides also seem to require higher molecula...

  19. Applications of Important Polysaccharides in Drug Delivery.

    PubMed

    Huang, Gangliang; Mei, Xinya; Xiao, Feng; Chen, Xin; Tang, Qilin; Peng, Daquan

    2015-01-01

    Polysaccharide is a kind of biological material, which has good biocompatibility, non-toxicity, and non-immunogenicity. So, the polysaccharide has widely been applied in drug delivery system. The applications of chitosan, hyaluronic acid and dextran in drug delivery have been summarized herein. PMID:25578889

  20. Synthesis of part structures of Cryptococcus neoformans serotype C capsular polysaccharide.

    PubMed

    Guazzelli, Lorenzo; McCabe, Orla; Oscarson, Stefan

    2016-10-01

    Cryptococcus neoformans is a fungal pathogen that can cause life-threatening infections in immunocompromised patients. The development of a vaccine based on the capsular polysaccharide of C. neoformans is still an open challenge due to the heterogeneity of the capsular polysaccharide and the difficulty of identifying protective epitopes. Therefore, construction of structurally defined part structures of the C. neoformans GXM capsule is in great demand. Herein is presented the synthesis of a 3-O-naphthalenylmethyl protected trisaccharide thioglycoside building block which is present in C. neoformans serotype C polysaccharide. Its property as a donor in a glycosylation reaction with a model acceptor has been evaluated together with its behaviour as an acceptor following removal of the temporary protecting group. The heavily branched hexasaccharide was obtained in good yields and excellent α-selectivity. The frame shifted octasaccharide structural triad motif for serotype C was also prepared following the same building block strategy. For the first time this structural motif, which is the most substituted amongst the four C. neoformans serotypes, was prepared. Three synthesized C. neoformans serotype C fragments of varying size, from penta-up to octasaccharide, were deprotected and will be included in unique glycoarrays to further investigate the possibility to develop a synthetic vaccine against this pathogen. PMID:27423877

  1. Role of the Apt1 Protein in Polysaccharide Secretion by Cryptococcus neoformans

    PubMed Central

    Rizzo, Juliana; Oliveira, Débora L.; Joffe, Luna S.; Hu, Guanggan; Gazos-Lopes, Felipe; Fonseca, Fernanda L.; Almeida, Igor C.; Frases, Susana; Kronstad, James W.

    2014-01-01

    Flippases are key regulators of membrane asymmetry and secretory mechanisms. Vesicular polysaccharide secretion is essential for the pathogenic mechanisms of Cryptococcus neoformans. On the basis of the observations that flippases are required for polysaccharide secretion in plants and the putative Apt1 flippase is required for cryptococcal virulence, we analyzed the role of this enzyme in polysaccharide release by C. neoformans, using a previously characterized apt1Δ mutant. Mutant and wild-type (WT) cells shared important phenotypic characteristics, including capsule morphology and dimensions, glucuronoxylomannan (GXM) composition, molecular size, and serological properties. The apt1Δ mutant, however, produced extracellular vesicles (EVs) with a lower GXM content and different size distribution in comparison with those of WT cells. Our data also suggested a defective intracellular GXM synthesis in mutant cells, in addition to changes in the architecture of the Golgi apparatus. These findings were correlated with diminished GXM production during in vitro growth, macrophage infection, and lung colonization. This phenotype was associated with decreased survival of the mutant in the lungs of infected mice, reduced induction of interleukin-6 (IL-6) cytokine levels, and inefficacy in colonization of the brain. Taken together, our results indicate that the lack of APT1 caused defects in both GXM synthesis and vesicular export to the extracellular milieu by C. neoformans via processes that are apparently related to the pathogenic mechanisms used by this fungus during animal infection. PMID:24337112

  2. Role of the Apt1 protein in polysaccharide secretion by Cryptococcus neoformans.

    PubMed

    Rizzo, Juliana; Oliveira, Débora L; Joffe, Luna S; Hu, Guanggan; Gazos-Lopes, Felipe; Fonseca, Fernanda L; Almeida, Igor C; Frases, Susana; Kronstad, James W; Rodrigues, Marcio L

    2014-06-01

    Flippases are key regulators of membrane asymmetry and secretory mechanisms. Vesicular polysaccharide secretion is essential for the pathogenic mechanisms of Cryptococcus neoformans. On the basis of the observations that flippases are required for polysaccharide secretion in plants and the putative Apt1 flippase is required for cryptococcal virulence, we analyzed the role of this enzyme in polysaccharide release by C. neoformans, using a previously characterized apt1Δ mutant. Mutant and wild-type (WT) cells shared important phenotypic characteristics, including capsule morphology and dimensions, glucuronoxylomannan (GXM) composition, molecular size, and serological properties. The apt1Δ mutant, however, produced extracellular vesicles (EVs) with a lower GXM content and different size distribution in comparison with those of WT cells. Our data also suggested a defective intracellular GXM synthesis in mutant cells, in addition to changes in the architecture of the Golgi apparatus. These findings were correlated with diminished GXM production during in vitro growth, macrophage infection, and lung colonization. This phenotype was associated with decreased survival of the mutant in the lungs of infected mice, reduced induction of interleukin-6 (IL-6) cytokine levels, and inefficacy in colonization of the brain. Taken together, our results indicate that the lack of APT1 caused defects in both GXM synthesis and vesicular export to the extracellular milieu by C. neoformans via processes that are apparently related to the pathogenic mechanisms used by this fungus during animal infection.

  3. Characterization of the Burkholderia pseudomallei K96243 Capsular Polysaccharide I Coding Region

    PubMed Central

    Cuccui, Jon; Milne, Timothy S.; Harmer, Nicholas; George, Alison J.; Harding, Sarah V.; Dean, Rachel E.; Scott, Andrew E.; Sarkar-Tyson, Mitali; Wren, Brendan W.; Prior, Joann L.

    2012-01-01

    Burkholderia pseudomallei is the causative agent of melioidosis, a disease endemic to regions of Southeast Asia and Northern Australia. Both humans and a range of other animal species are susceptible to melioidosis, and the production of a group 3 polysaccharide capsule in B. pseudomallei is essential for virulence. B. pseudomallei capsular polysaccharide (CPS) I comprises unbranched manno-heptopyranose residues and is encoded by a 34.5-kb locus on chromosome 1. Despite the importance of this locus, the role of all of the genes within this region is unclear. We inactivated 18 of these genes and analyzed their phenotype using Western blotting and immunofluorescence staining. Furthermore, by combining this approach with bioinformatic analysis, we were able to develop a model for CPS I biosynthesis and export. We report that inactivating gmhA, wcbJ, and wcbN in B. pseudomallei K96243 retains the immunogenic integrity of the polysaccharide despite causing attenuation in the BALB/c murine infection model. Mice immunized with the B. pseudomallei K96243 mutants lacking a functional copy of either gmhA or wcbJ were afforded significant levels of protection against a wild-type B. pseudomallei K96243 challenge. PMID:22252864

  4. Capsule HRB-21 postirradiation examination plan

    SciTech Connect

    Packan, N.H.; Kania, M.J.; Shrader, L.G.

    1990-03-01

    Irradiation capsule HRB-21 is a test capsule designed to provide Modular High-Temperature Gas-Cooled Reactor (MHTGR) coated particle fuel performance data under test reactor conditions representative of normal MHTGR operation. The irradiated fuel will also be used for postirradiation heating in a controlled atmosphere allowing acquisition of fission product release data at sustained high temperatures. The in-reactor performance data, the postirradiation examination data, and the postirradiation heating data will be used for the validation of fuel performance models under normal and off-normal operating conditions. The accelerated irradiation is to take place in the High Flux Isotope Reactor (HFIR) at ORNL. This report identifies the procedures to be followed in carrying out the postirradiation disassembly and examination of HRB-21. Included is a description of the capsule, a detailed sequence of steps for disassembly of the capsule, a description of the postirradiation examination techniques to be employed, and specifications for the storage of capsule components and the reporting of results. 9 refs., 6 figs., 2 tabs.

  5. Lubricin in human breast tissue expander capsules.

    PubMed

    Cheriyan, Thomas; Guo, Lifei; Orgill, Dennis P; Padera, Robert F; Schmid, Thomas M; Spector, Myron

    2012-10-01

    Capsular contraction is the most common complication of breast reconstruction surgery. While presence of the contractile protein alpha smooth muscle actin (α-SMA) is considered among the causes of capsular contraction, the exact etiology and pathophysiology is not fully understood. The objective of this study was to investigate the possible role of lubricin in capsular formation and contraction by determining the presence and distribution of the lubricating protein lubricin in human breast tissue expander capsules. Related aims were to evaluate select histopathologic features of the capsules, and the percentage of cells expressing α-SMA, which reflects the myofibroblast phenotype. Capsules from tissue expanders were obtained from eight patients. Lubricin, at the tissue-implant interface, in the extracellular matrix, and in cells, and α-SMA-containing cells were evaluated immunohistochemically. The notable finding was that lubricin was identified in all tissue expander capsules: as a discrete layer at the tissue-implant interface, extracellular, and intracellular. There was a greater amount of lubricin in the extracellular matrix in the intimal-subintimal zone when compared with the tissue away from the implant. Varying degrees of synovial metaplasia were seen at the tissue-implant interface. α-SMA-containing cells were also seen in all but one patient. The findings might help us better understand factors involved in capsule formation.

  6. High-quality RNA extraction from small cardamom tissues rich in polysaccharides and polyphenols.

    PubMed

    Nadiya, Fasiludeen; Anjali, Narayanannair; Gangaprasad, Appukuttannair; Sabu, Kalluvettankuzhy Krishnannair

    2015-09-15

    Due to the presence of a diverse array of metabolites, no standard method of RNA isolation is available for plants. We noted that polysaccharide and polyphenol contents of cardamom tissues critically hinder the RNA extraction procedure. Hence, we attempted several methods for obtaining intact mRNA and small RNA from various cardamom tissues. It was found that protocols involving a combination of commercial kits and conventional CTAB (cetyl trimethylammonium bromide) methods yielded RNA with good purity, higher yield, and good integrity. The total RNA isolated through this approach was found to be amenable for transcriptome and small RNA analysis through next-generation sequencing platforms. PMID:26048648

  7. High-quality RNA extraction from small cardamom tissues rich in polysaccharides and polyphenols.

    PubMed

    Nadiya, Fasiludeen; Anjali, Narayanannair; Gangaprasad, Appukuttannair; Sabu, Kalluvettankuzhy Krishnannair

    2015-09-15

    Due to the presence of a diverse array of metabolites, no standard method of RNA isolation is available for plants. We noted that polysaccharide and polyphenol contents of cardamom tissues critically hinder the RNA extraction procedure. Hence, we attempted several methods for obtaining intact mRNA and small RNA from various cardamom tissues. It was found that protocols involving a combination of commercial kits and conventional CTAB (cetyl trimethylammonium bromide) methods yielded RNA with good purity, higher yield, and good integrity. The total RNA isolated through this approach was found to be amenable for transcriptome and small RNA analysis through next-generation sequencing platforms.

  8. Biochemical, genetic, and serological characterization of two capsule subtypes among Streptococcus pneumoniae Serotype 20 strains: discovery of a new pneumococcal serotype.

    PubMed

    Calix, Juan J; Porambo, Richard J; Brady, Allison M; Larson, Thomas R; Yother, Janet; Abeygunwardana, Chitrananda; Nahm, Moon H

    2012-08-10

    The bacterial pathogen Streptococcus pneumoniae expresses one of over 90 structurally distinct polysaccharide (PS) capsule serotypes. Prior PS structural analyses of the vaccine-associated serotype 20 do not agree with reports describing the genes that mediate capsule synthesis. Furthermore, using immunized human sera-based assays, serological differences were recently noted among strains typed as serotype 20. We examined the capsule structures of two serologically dissimilar serotype 20 strains, 20α and 20β, by extensive biochemical analysis. 20α PS was composed of the previously described serotype 20 hexasaccharide repeat unit, whereas the 20β PS was composed of a novel heptasaccharide repeat unit containing an extra branching α-glucose residue. Genetic analysis of the subtypes revealed that 20α may have arisen from a 20β progenitor following loss of function mutation to the glycosyltransferase gene whaF. Conventional serotyping methods using rabbit polyclonal or mouse monoclonal antibodies were unable to distinguish the subtypes. However, genetic analysis of multiple "serotype 20" clinical isolates revealed that all strains contain the 20β genotype. We propose naming bacteria that express the previously described 20α capsule structure 20A and bacteria that express the novel 20β capsule structure 20B, a new pneumococcal serotype.

  9. Unsteady Pressures on a Generic Capsule Shape

    NASA Technical Reports Server (NTRS)

    Burnside, Nathan; Ross, James C.

    2015-01-01

    While developing the aerodynamic database for the Orion spacecraft, the low-speed flight regime (transonic and below) proved to be the most difficult to predict and measure accurately. The flow over the capsule heat shield in descent flight was particularly troublesome for both computational and experimental efforts due to its unsteady nature and uncertainty about the boundary layer state. The data described here were acquired as part of a study to improve the understanding of the overall flow around a generic capsule. The unsteady pressure measurements acquired on a generic capsule shape are presented along with a discussion about the effects of various flight conditions and heat-shield surface roughness on the resulting pressure fluctuations.

  10. Laundry detergent capsules and pediatric poisoning

    PubMed Central

    Bonney, Asha G.; Mazor, Suzan; Goldman, Ran D.

    2013-01-01

    Abstract Question A 4-year-old girl was brought into the emergency department vomiting after having had ingested a laundry detergent capsule (LDC) from under the sink at her house. What is the risk of LDC poisoning? What can be done to treat these children? Answer Laundry detergent capsules are relatively new to supermarket shelves in North America, and there has been an emergence of case reports in the literature describing LDC poisoning, which is worse than poisoning from other laundry detergents. Very little is known about the mechanisms causing these severe reactions, which include airway compromise and esophageal perforation, but the attractive appearance of these capsules and easy access at home has governments and health officials concerned about an increase in poisoning. No residual problems have been associated with these cases to date; however, further research is needed to assess long-term effects. PMID:24336541

  11. The first capsule implosion experiments on Orion

    NASA Astrophysics Data System (ADS)

    Garbett, W. J.; Horsfield, C. J.; Gales, S. G.; Leatherland, A. E.; Rubery, M. S.; Coltman, J. E.; Meadowcroft, A. E.; Rice, S. J.; Simons, A. J.; Woolhead, V. E.

    2016-05-01

    Direct drive capsule implosions are being developed on the Orion laser at AWE as a platform for ICF and HED physics experiments. The Orion facility combines both long pulse and short-pulse beams, making it well suited for studying the physics of alternative ignition approaches. Orion implosions also provide the opportunity to study aspects of polar direct drive. Limitations on drive symmetry from the relatively small number of laser beams makes predictive modelling of the implosions challenging, resulting in some uncertainty in the expected capsule performance. Initial experiments have been fielded to evaluate baseline capsule performance and inform future design optimization. Highly promising DD fusion neutron yields in excess of 109 have been recorded. Results from the experiments are presented alongside radiation-hydrocode modelling.

  12. Spectral measurements of asymmetrically irradiated capsule backlighters

    NASA Astrophysics Data System (ADS)

    Keiter, P. A.; Drake, R. P.

    2016-11-01

    Capsule backlighters provide a quasi-continuum x-ray spectrum over a wide range of photon energies [J. F. Hansen et al., Rev. Sci. Instrum. 79, 013504 (2008)]. Ideally one irradiates the capsule backlighter symmetrically, however, in complex experimental geometries, this is not always possible. In recent experiments we irradiated capsule backlighters asymmetrically and measured the x-ray spectrum from multiple directions. We will present time-integrated spectra over the photon energy range of 2-13 keV and time-resolved spectra over the photon energy range of 2-3 keV. We will compare the spectra from different lines of sight to determine if the laser asymmetry results in an angular dependence in the x-ray emission.

  13. Capsule endoscopy—A mechatronics perspective

    NASA Astrophysics Data System (ADS)

    Lin, Lin; Rasouli, Mahdi; Kencana, Andy Prima; Tan, Su Lim; Wong, Kai Juan; Ho, Khek Yu; Phee, Soo Jay

    2011-03-01

    The recent advances in integrated circuit technology, wireless communication, and sensor technology have opened the door for development of miniature medical devices that can be used for enhanced monitoring and treatment of medical conditions. Wireless capsule endoscopy is one of such medical devices that has gained significant attention during the past few years. It is envisaged that future wireless capsule endoscopies replace traditional endoscopy procedures by providing advanced functionalities such as active locomotion, body fluid/tissue sampling, and drug delivery. Development of energy-efficient miniaturized actuation mechanisms is a key step toward achieving this goal. Here, we review some of the actuators that could be integrated into future wireless capsules and discuss the existing challenges.

  14. Calcium Signaling in Intact Dorsal Root Ganglia

    PubMed Central

    Gemes, Geza; Rigaud, Marcel; Koopmeiners, Andrew S.; Poroli, Mark J.; Zoga, Vasiliki; Hogan, Quinn H.

    2013-01-01

    Background Ca2+ is the dominant second messenger in primary sensory neurons. In addition, disrupted Ca2+ signaling is a prominent feature in pain models involving peripheral nerve injury. Standard cytoplasmic Ca2+ recording techniques use high K+ or field stimulation and dissociated neurons. To compare findings in intact dorsal root ganglia, we used a method of simultaneous electrophysiologic and microfluorimetric recording. Methods Dissociated neurons were loaded by bath-applied Fura-2-AM and subjected to field stimulation. Alternatively, we adapted a technique in which neuronal somata of intact ganglia were loaded with Fura-2 through an intracellular microelectrode that provided simultaneous membrane potential recording during activation by action potentials (APs) conducted from attached dorsal roots. Results Field stimulation at levels necessary to activate neurons generated bath pH changes through electrolysis and failed to predictably drive neurons with AP trains. In the intact ganglion technique, single APs produced measurable Ca2+ transients that were fourfold larger in presumed nociceptive C-type neurons than in nonnociceptive Aβ-type neurons. Unitary Ca2+ transients summated during AP trains, forming transients with amplitudes that were highly dependent on stimulation frequency. Each neuron was tuned to a preferred frequency at which transient amplitude was maximal. Transients predominantly exhibited monoexponential recovery and had sustained plateaus during recovery only with trains of more than 100 APs. Nerve injury decreased Ca2+ transients in C-type neurons, but increased transients in Aβ-type neurons. Conclusions Refined observation of Ca2+ signaling is possible through natural activation by conducted APs in undissociated sensory neurons and reveals features distinct to neuronal types and injury state. PMID:20526180

  15. Quantitative proteomic analysis of intact plastids.

    PubMed

    Shiraya, Takeshi; Kaneko, Kentaro; Mitsui, Toshiaki

    2014-01-01

    Plastids are specialized cell organelles in plant cells that are differentiated into various forms including chloroplasts, chromoplasts, and amyloplasts, and fulfill important functions in maintaining the overall cell metabolism and sensing environmental factors such as sunlight. It is therefore important to grasp the mechanisms of differentiation and functional changes of plastids in order to enhance the understanding of vegetality. In this chapter, details of a method for the extraction of intact plastids that makes analysis possible while maintaining the plastid functions are provided; in addition, a quantitative shotgun method for analyzing the composition and changes in the content of proteins in plastids as a result of environmental impacts is described. PMID:24136541

  16. Quantitative proteomic analysis of intact plastids.

    PubMed

    Shiraya, Takeshi; Kaneko, Kentaro; Mitsui, Toshiaki

    2014-01-01

    Plastids are specialized cell organelles in plant cells that are differentiated into various forms including chloroplasts, chromoplasts, and amyloplasts, and fulfill important functions in maintaining the overall cell metabolism and sensing environmental factors such as sunlight. It is therefore important to grasp the mechanisms of differentiation and functional changes of plastids in order to enhance the understanding of vegetality. In this chapter, details of a method for the extraction of intact plastids that makes analysis possible while maintaining the plastid functions are provided; in addition, a quantitative shotgun method for analyzing the composition and changes in the content of proteins in plastids as a result of environmental impacts is described.

  17. Water Landing Characteristics of a Reentry Capsule

    NASA Technical Reports Server (NTRS)

    1958-01-01

    Experimental and theoretical investigations have been made to determine the water-landing characteristics of a conical-shaped reentry capsule having a segment of a sphere as the bottom. For the experimental portion of the investigation, a 1/12-scale model capsule and a full-scale capsule were tested for nominal flight paths of 65 deg and 90 deg (vertical), a range of contact attitudes from -30 deg to 30 deg, and a full-scale vertical velocity of 30 feet per second at contact. Accelerations were measured by accelerometers installed at the centers of gravity of the model and full-scale capsules. For the model test the accelerations were measured along the X-axis (roll) and Z-axis (yaw) and for the full-scale test they were measured along the X-axis (roll), Y-axis (pitch), and Z-axis (yaw). Motions and displacements of the capsules that occurred after contact were determined from high-speed motion pictures. The theoretical investigation was conducted to determine the accelerations that might occur along the X-axis when the capsule contacted the water from a 90 deg flight path at a 0 deg attitude. Assuming a rigid body, computations were made from equations obtained by utilizing the principle of the conservation of momentum. The agreement among data obtained from the model test, the full-scale test, and the theory was very good. The accelerations along the X-axis, for a vertical flight path and 0 deg attitude, were in the order of 40g. For a 65 deg flight path and 0 deg attitude, the accelerations along the X-axis were in the order of 50g. Changes in contact attitude, in either the positive or negative direction from 0 deg attitude, considerably reduced the magnitude of the accelerations measured along the X-axis. Accelerations measured along the Y- and Z-axes were relatively small at all test conditions.

  18. Video capsule endoscopy in inflammatory bowel disease

    PubMed Central

    Collins, Paul D

    2016-01-01

    Video capsule endoscopy (VCE) has evolved to become an important tool for the non-invasive examination of the small bowel, which hitherto had been relatively inaccessible to direct visualisation. VCE has been shown to play a role in monitoring the activity of small bowel Crohn’s disease and can be used to assess the response to anti-inflammatory treatment in Crohn’s disease. For those patients with Crohn’s disease who have undergone an intestinal resection, VCE has been assessed as a tool to detect post-operative recurrence. VCE may also aid in the reclassification of patients with a diagnosis of Inflammatory Bowel Disease Unclassified to Crohn’s disease. The evolution of colon capsule endoscopy (CCE) has expanded the application of this technology further. The use of CCE to assess the activity of ulcerative colitis has been described. This advance in capsule technology has also fuelled interest in its potential role as a minimally invasive tool to assess the whole of GI tract opening the possibility of its use for the panenteric assessment of Crohn’s disease. VCE is a safe procedure. However, the risk of a retained capsule is higher in patients with suspected or confirmed Crohn’s disease compared with patients having VCE examination for other indications. A retained video capsule is rare after successful passage of a patency capsule which may be utilised to pre-screen patients undergoing VCE. This paper describes the use of VCE in the assessment of inflammatory bowel disease. PMID:27499830

  19. Treatment of adhesive capsulitis: a review

    PubMed Central

    D’Orsi, Giovanni Maria; Via, Alessio Giai; Frizziero, Antonio; Oliva, Francesco

    2012-01-01

    Summary Adhesive capsulitis is a condition “difficult to define, difficult to treat and difficult to explain from the point of view of pathology”. This Codman’s assertion is still actual because of a variable nomenclature, an inconsistent reporting of disease staging and many types of treatment. There is no consensus on how the best way best to manage patients with this condition, so we want to provide an evidence-based overview regarding the effectiveness of conservative and surgical interventions to treat adhesive capsulitis. PMID:23738277

  20. Capsules with external navigation and triggered release.

    PubMed

    Shchukin, Dmitry G; Shchukina, Elena

    2014-10-01

    Encapsulation is an important technology for pharmaceutical industry, food production, et cetera. Its current level of development requires capsule functionalization. One of the interesting ideas to provide new functionality to the microcapsule and nanocapsule is layer-by-layer deposition of functional species. This technique provides step-by-step adsorption of various species (polyelectrolytes, nanoparticles, proteins) when the layer growth is controlled by electrostatic, hydrogen bonding, hydrophobic forces and forming multilayer shells with nanometer precision. This review article introduces recent achievements of layer-by-layer technique attaining external navigation ability and release properties the capsule shell.

  1. 50 CFR 622.276 - Landing fish intact.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 12 2014-10-01 2014-10-01 false Landing fish intact. 622.276 Section 622... Wahoo Fishery Off the Atlantic States § 622.276 Landing fish intact. (a) Dolphin and wahoo in or from the Atlantic EEZ must be maintained with head and fins intact. Such fish may be eviscerated,...

  2. 50 CFR 622.381 - Landing fish intact.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 12 2014-10-01 2014-10-01 false Landing fish intact. 622.381 Section 622... Migratory Pelagic Resources (Gulf of Mexico and South Atlantic) § 622.381 Landing fish intact. (a) Cobia... head and fins intact. Such fish may be eviscerated, gilled, and scaled, but must otherwise...

  3. 50 CFR 622.276 - Landing fish intact.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 12 2013-10-01 2013-10-01 false Landing fish intact. 622.276 Section 622... Wahoo Fishery Off the Atlantic States § 622.276 Landing fish intact. (a) Dolphin and wahoo in or from the Atlantic EEZ must be maintained with head and fins intact. Such fish may be eviscerated,...

  4. 7 CFR 160.29 - Containers to remain intact.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Containers to remain intact. 160.29 Section 160.29... STANDARDS FOR NAVAL STORES Analysis, Inspection, and Grading on Request § 160.29 Containers to remain intact... the containers holding such naval stores remain intact as sampled until the analysis,...

  5. 33 CFR 157.22 - Intact stability requirements.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Intact stability requirements... OIL IN BULK Design, Equipment, and Installation § 157.22 Intact stability requirements. All tank ships of 5,000 DWT and above contracted after December 3, 2001 must comply with the intact...

  6. 33 CFR 157.22 - Intact stability requirements.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Intact stability requirements... OIL IN BULK Design, Equipment, and Installation § 157.22 Intact stability requirements. All tank ships of 5,000 DWT and above contracted after December 3, 2001 must comply with the intact...

  7. 33 CFR 157.22 - Intact stability requirements.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Intact stability requirements... OIL IN BULK Design, Equipment, and Installation § 157.22 Intact stability requirements. All tank ships of 5,000 DWT and above contracted after December 3, 2001 must comply with the intact...

  8. 33 CFR 157.22 - Intact stability requirements.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Intact stability requirements... OIL IN BULK Design, Equipment, and Installation § 157.22 Intact stability requirements. All tank ships of 5,000 DWT and above contracted after December 3, 2001 must comply with the intact...

  9. 33 CFR 157.22 - Intact stability requirements.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Intact stability requirements... OIL IN BULK Design, Equipment, and Installation § 157.22 Intact stability requirements. All tank ships of 5,000 DWT and above contracted after December 3, 2001 must comply with the intact...

  10. Enzymatic method for improving the injectability of polysaccharides

    DOEpatents

    Griffith, William L.; Compere, Alicia L.; Holleman, James W.

    1982-01-01

    A method for enhancing the ability of polysaccharides in aqueous solution to flow through a porous medium comprises contacting the polysaccharides with an endoenzyme capable of hydrolyzing at least one of the linkages of the sugar units of the polysaccharides and maintaining the polysaccharides in contact with the enzyme under hydrolysis conditions for a time sufficient to decrease the tendency of the polysaccharides to plug the porous medium yet insufficient to decrease the viscosity of the aqueous polysaccharides by more than 25%. The partially hydrolyzed polysaccharides are useful as thickening agents for flooding water used to recover oil from oil-containing subterranean formations.

  11. Induction of Overt Menstruation in Intact Mice

    PubMed Central

    Rudolph, Marion; Döcke, Wolf-Dietrich; Müller, Andrea; Menning, Astrid; Röse, Lars; Zollner, Thomas Matthias; Gashaw, Isabella

    2012-01-01

    The complex tissue remodeling process of menstruation is experienced by humans and some primates, whereas most placental mammals, including mice, go through an estrous cycle. How menstruation and the underlying mechanisms evolved is still unknown. Here we demonstrate that the process of menstruation is not just species-specific but also depends on factors which can be induced experimentally. In intact female mice endogenous progesterone levels were raised by the induction of pseudopregnancy. Following an intrauterine oil injection, the decidualization of the endometrium was reliably induced as a prerequisite for menstruation. The natural drop of endogenous progesterone led to spontaneous breakdown of endometrial tissue within an average of 3 days post induction of decidualization. Interestingly, morphological changes such as breakdown and repair of the endometrial layer occurred in parallel in the same uterine horn. Most importantly, endometrial breakdown was accompanied by vaginally visible (overt) bleeding and flushing out of shed tissue comparable to human menstruation. Real-time PCR data clearly showed temporal changes in the expression of multiple factors participating in inflammation, angiogenesis, tissue modulation, proliferation, and apoptosis, as has been described for human menstruating endometrium. In conclusion, human menstruation can be mimicked in terms of extravaginally visible bleeding, tissue remodeling, and gene regulation in naturally non-menstruating species such as intact female mice without the need for an exogenous hormone supply. PMID:22412950

  12. An Empirical Failure Criterion for Intact Rocks

    NASA Astrophysics Data System (ADS)

    Peng, Jun; Rong, Guan; Cai, Ming; Wang, Xiaojiang; Zhou, Chuangbing

    2014-03-01

    The parameter m i is an important rock property parameter required for use of the Hoek-Brown failure criterion. The conventional method for determining m i is to fit a series of triaxial compression test data. In the absence of laboratory test data, guideline charts have been provided by Hoek to estimate the m i value. In the conventional Hoek-Brown failure criterion, the m i value is a constant for a given rock. It is observed that using a constant m i may not fit the triaxial compression test data well for some rocks. In this paper, a negative exponent empirical model is proposed to express m i as a function of confinement, and this exercise leads us to a new empirical failure criterion for intact rocks. Triaxial compression test data of various rocks are used to fit parameters of this model. It is seen that the new empirical failure criterion fits the test data better than the conventional Hoek-Brown failure criterion for intact rocks. The conventional Hoek-Brown criterion fits the test data well in the high-confinement region but fails to match data well in the low-confinement and tension regions. In particular, it overestimates the uniaxial compressive strength (UCS) and the uniaxial tensile strength of rocks. On the other hand, curves fitted by the proposed empirical failure criterion match test data very well, and the estimated UCS and tensile strength agree well with test data.

  13. Carbohydrate-binding modules promote the enzymatic deconstruction of intact plant cell walls by targeting and proximity effects.

    PubMed

    Hervé, Cécile; Rogowski, Artur; Blake, Anthony W; Marcus, Susan E; Gilbert, Harry J; Knox, J Paul

    2010-08-24

    Cell wall degrading enzymes have a complex molecular architecture consisting of catalytic modules and noncatalytic carbohydrate-binding modules (CBMs). The function of CBMs in cell wall degrading processes is poorly understood. Here, we have evaluated the potential enzyme-targeting function of CBMs in the context of intact primary and secondary cell wall deconstruction. The capacity of a pectate lyase to degrade pectic homogalacturonan in primary cell walls was potentiated by cellulose-directed CBMs but not by xylan-directed CBMs. Conversely, the arabinofuranosidase-mediated removal of side chains from arabinoxylan in xylan-rich and cellulose-poor wheat grain endosperm cell walls was enhanced by a xylan-binding CBM but less so by a crystalline cellulose-specific module. The capacity of xylanases to degrade xylan in secondary cell walls was potentiated by both xylan- and cellulose-directed CBMs. These studies demonstrate that CBMs can potentiate the action of a cognate catalytic module toward polysaccharides in intact cell walls through the recognition of nonsubstrate polysaccharides. The targeting actions of CBMs therefore have strong proximity effects within cell wall structures, explaining why cellulose-directed CBMs are appended to many noncellulase cell wall hydrolases.

  14. Rheology of interfacial protein-polysaccharide composites

    NASA Astrophysics Data System (ADS)

    Fischer, P.

    2013-05-01

    The morphology and mechanical properties of protein adsorption layers can significantly be altered by the presence of surfactants, lipids, particles, other proteins, and polysaccharides. In food emulsions, polysaccharides are primarily considered as bulk thickener but can under appropriate environmental conditions stabilize or destabilize the protein adsorption layer and, thus, the entire emulsion system. Despite their ubiquitous usage as stabilization agent, relatively few investigations focus on the interfacial rheology of composite protein/polysaccharide adsorption layers. The manuscript provides a brief review on both main stabilization mechanisms, thermodynamic phase separation and electrostatic interaction and discusses the rheological response in light of the environmental conditions such as ionic strength and pH.

  15. Recollections of Parent Characteristics and Attachment Patterns for College Women of Intact vs. Non-Intact Families

    ERIC Educational Resources Information Center

    Kilmann, Peter R.; Carranza, Laura V.; Vendemia, Jennifer M. C.

    2006-01-01

    This study contrasted offsprings' attachment patterns and recollections of parent characteristics in two college samples: 147 females from intact biological parents and 157 females of parental divorce. Secure females from intact or non-intact families rated parents positively, while insecure females rated parents as absent, distant, and demanding.…

  16. 21 CFR 520.608 - Dicloxacillin sodium monohydrate capsules.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Dicloxacillin sodium monohydrate capsules. 520.608 Section 520.608 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Dicloxacillin sodium monohydrate capsules. (a) Specifications. Each capsule contains dicloxacillin...

  17. 21 CFR 872.3110 - Dental amalgam capsule.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Dental amalgam capsule. 872.3110 Section 872.3110...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3110 Dental amalgam capsule. (a) Identification. A dental amalgam capsule is a container device in which silver alloy is intended to be mixed with...

  18. 21 CFR 872.3110 - Dental amalgam capsule.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Dental amalgam capsule. 872.3110 Section 872.3110...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3110 Dental amalgam capsule. (a) Identification. A dental amalgam capsule is a container device in which silver alloy is intended to be mixed with...

  19. 21 CFR 872.3110 - Dental amalgam capsule.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Dental amalgam capsule. 872.3110 Section 872.3110...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3110 Dental amalgam capsule. (a) Identification. A dental amalgam capsule is a container device in which silver alloy is intended to be mixed with...

  20. Distinct Cellular Pathways for Induction of CD4+ T Cell-Dependent Antibody Responses to Antigen Expressed by Intact Bacteria Versus Isolated Soluble Antigen.

    PubMed

    Kar, Swagata; Colino, Jesus; Snapper, Clifford M

    2016-05-15

    Uptake of intact bacteria and soluble Ags by APCs is mediated by phagocytosis and endocytosis or pinocytosis, respectively. Thus, we predicted that injection of clodronate-containing liposomes (CLs), which selectively deplete cells efficient in phagocytosis, would inhibit murine CD4(+) T cell-dependent IgG responses to Ags expressed by intact bacteria but not isolated soluble Ags. Surprisingly, injection of CLs markedly inhibited protein-specific IgG responses to intact, heat-killed Streptococcus pneumoniae, as well as a soluble OVA-polysaccharide conjugate or OVA alone. IgG anti-polysaccharide responses to bacteria and conjugate were also reduced, but more modestly. In both instances, CL-mediated inhibition was associated with a significant reduction in induced germinal centers and CD4(+) germinal center T follicular helper cells. However, CL injection, which largely abrogated the proliferative response of adoptively transferred OVA peptide-specific-transgenic CD4(+) T cells in response to immunization with S. pneumoniae expressing OVA peptide, did not inhibit T cell proliferation in response to OVA-polysaccharide conjugate or OVA. In this regard, monocyte-derived cells, depleted by CLs, internalized S. pneumoniae in vivo, whereas CD11c(low) dendritic cells, unaffected by CL injection, internalized soluble OVA. Ex vivo isolation and coculture of these respective APCs from S. pneumoniae- or OVA-immunized mice with OVA-specific T cells, in the absence of exogenous Ag, demonstrated their selective ability to induce T cell activation. These data suggest that, although distinct APCs initiate CD4(+) T cell activation in response to Ag expressed by intact bacteria versus Ag in soluble form, CL-sensitive cells appear to be necessary for the subsequent IgG responses to both forms of Ag.

  1. Serogroup quantitation of multivalent polysaccharide and polysaccharide-conjugate meningococcal vaccines from China.

    PubMed

    Cook, Matthew C; Gibeault, Sabrina; Filippenko, Vasilisa; Ye, Qiang; Wang, Junzhi; Kunkel, Jeremy P

    2013-07-01

    The active components of most meningococcal vaccines are four antigenic serogroup capsular polysaccharides (A, C, Y, W135). The vaccines, monovalent or multivalent mixtures of either free polysaccharides or polysaccharides conjugated to antigenic carrier proteins, may be in liquid or lyophilised formulations, with or without excipients. Acid hydrolysis and chromatographic methods for serogroup quantitation, which were previously optimised and qualified using polysaccharide-based standards and a narrow range of real vaccines, are here challenged with multiple lots of a broad assortment of additional multivalent polysaccharide-based meningococcal vaccine products. Centrifugal filtration successfully removed all interfering lactose excipient without loss of polysaccharides to allow for the determination of Y and W135 serogroups. Replicate operations by three different analysts indicated high method reproducibility. Results indicated some lot-to-lot and product-to-product variations. However, all vaccines were within general specifications for each serogroup polysaccharide, with the exception of all lots of one polysaccharide vaccine - which by these methods were found to be deficient in the serogroup A component only. These robust techniques are very useful for the evaluation of antigen content and consistency of manufacture. The deformulation, hydrolysis and chromatographic methods may be adaptable for the evaluation of other types of polysaccharide-based vaccines.

  2. Design of Endoscopic Capsule With Multiple Cameras.

    PubMed

    Gu, Yingke; Xie, Xiang; Li, Guolin; Sun, Tianjia; Wang, Dan; Yin, Zheng; Zhang, Pengfei; Wang, Zhihua

    2015-08-01

    In order to reduce the miss rate of the wireless capsule endoscopy, in this paper, we propose a new system of the endoscopic capsule with multiple cameras. A master-slave architecture, including an efficient bus architecture and a four level clock management architecture, is applied for the Multiple Cameras Endoscopic Capsule (MCEC). For covering more area of the gastrointestinal tract wall with low power, multiple cameras with a smart image capture strategy, including movement sensitive control and camera selection, are used in the MCEC. To reduce the data transfer bandwidth and power consumption to prolong the MCEC's working life, a low complexity image compressor with PSNR 40.7 dB and compression rate 86% is implemented. A chipset is designed and implemented for the MCEC and a six cameras endoscopic capsule prototype is implemented by using the chipset. With the smart image capture strategy, the coverage rate of the MCEC prototype can achieve 98% and its power consumption is only about 7.1 mW. PMID:25376042

  3. Wireless capsule endoscopy: Perspectives beyond gastrointestinal bleeding

    PubMed Central

    Redondo-Cerezo, Eduardo; Sánchez-Capilla, Antonio Damián; De La Torre-Rubio, Paloma; De Teresa, Javier

    2014-01-01

    Wireless capsule endoscopy (CE) is a technology developed for the endoscopic exploration of the small bowel. The first capsule model was approved by the Food and Drug Administration in 2001, and its first and essential indication was occult gastrointestinal (GI) bleeding. Over subsequent years, this technology has been refined to provide superior resolution, increased battery life, and capabilities to view different parts of the GI tract. Indeed, cases for which CE proved useful have increased significantly over the last few years, with new indications for the small bowel and technical improvements that have expanded its use to other parts of the GI tract, including the esophagus and colon. The main challenges in the development of CE are new devices with the ability to provide therapy, air inflation for a better vision of the small bowel, biopsy sampling systems attached to the capsule and the possibility to guide and move the capsule with an external motion control. In this article we review the current and new indications of CE, and the evolving technological changes shaping this technology, which has a promising potential in the coming future of gastroenterology. PMID:25400450

  4. Extended School Year. Information Capsule. Volume 0910

    ERIC Educational Resources Information Center

    Blazer, Christie

    2010-01-01

    Extended school years are being considered by districts around the country as educators search for new ways to raise student achievement. The addition of time to the school calendar is also supported by President Barack Obama, who recently stated that American students do not spend enough time in school. This Information Capsule addresses research…

  5. CAPS Capsule. Volume 5, Number 1.

    ERIC Educational Resources Information Center

    Walz, Garry, Ed.; And Others

    Published 3 times yearly by the ERIC Clearinghouse on Counseling and Personnel Services, CAPS Capsule acquaints the reader with recent projects, meetings, publications and materials which are of interest to those in the helping professions. This issue introduces several new publications offered by CAPS under the name, "The Counselor's S x-Pack."…

  6. Student Mobility. Information Capsule. Volume 0608

    ERIC Educational Resources Information Center

    Blazer, Christie

    2007-01-01

    Mobility, rather than stability, has become the norm for students in schools across the United States. The student mobility rate is now higher in the United States than in any other industrialized country. This Information Capsule discusses the reasons for student mobility and the characteristics of highly mobile students and families. Research…

  7. Wireless capsule endoscopy: perspectives beyond gastrointestinal bleeding.

    PubMed

    Redondo-Cerezo, Eduardo; Sánchez-Capilla, Antonio Damián; De La Torre-Rubio, Paloma; De Teresa, Javier

    2014-11-14

    Wireless capsule endoscopy (CE) is a technology developed for the endoscopic exploration of the small bowel. The first capsule model was approved by the Food and Drug Administration in 2001, and its first and essential indication was occult gastrointestinal (GI) bleeding. Over subsequent years, this technology has been refined to provide superior resolution, increased battery life, and capabilities to view different parts of the GI tract. Indeed, cases for which CE proved useful have increased significantly over the last few years, with new indications for the small bowel and technical improvements that have expanded its use to other parts of the GI tract, including the esophagus and colon. The main challenges in the development of CE are new devices with the ability to provide therapy, air inflation for a better vision of the small bowel, biopsy sampling systems attached to the capsule and the possibility to guide and move the capsule with an external motion control. In this article we review the current and new indications of CE, and the evolving technological changes shaping this technology, which has a promising potential in the coming future of gastroenterology.

  8. Oligodeoxynucleotide Probes for Detecting Intact Cells

    NASA Technical Reports Server (NTRS)

    Rosson, Reinhardt A.; Maurina-Brunker, Julie; Langley, Kim; Pynnonen, Christine M.

    2004-01-01

    A rapid, sensitive test using chemiluminescent oligodeoxynucleotide probes has been developed for detecting, identifying, and enumerating intact cells. The test is intended especially for use in detecting and enumerating bacteria and yeasts in potable water. As in related tests that have been developed recently for similar purposes, the oligodeoxynucleotide probes used in this test are typically targeted at either singlecopy deoxyribonucleic acid (DNA) genes (such as virulence genes) or the multiple copies (10,000 to 50,000 copies per cell) of 16S ribosomal ribonucleic acids (rRNAs). Some of those tests involve radioisotope or fluorescent labeling of the probes for reporting hybridization of probes to target nucleic acids. Others of those tests involve labeling with enzymes plus the use of chemiluminescent or chromogenic substrates to report hybridization via color or the emission of light, respectively. The present test is of the last-mentioned type. The chemiluminescence in the present test can be detected easily with relatively simple instrumentation. In developing the present test, the hybridization approach was chosen because hybridization techniques are very specific. Hybridization detects stable, inheritable genetic targets within microorganisms. These targets are not dependent on products of gene expression that can vary with growth conditions or physiological states of organisms in test samples. Therefore, unique probes can be designed to detect and identify specific genera or species of bacteria or yeast (in terms of rRNA target sequences) or can be designed to detect and identify virulence genes (genomic target sequences). Because of the inherent specificity of this system, there are few problems of cross-reactivity. Hybridization tests are rapid, but hybridization tests now available commercially lack sensitivity; typically, between 10(exp 6) and 10(exp 7) cells of the target organism are needed to ensure a reliable test. Consequently, the numbers of

  9. Water Landing Characteristics of a Reentry Capsule

    NASA Technical Reports Server (NTRS)

    1958-01-01

    Water Landing Characteristics of a Reentry Capsule. Experimental and theoretical investigations have been made to determine the water-landing characteristics of a conical-shaped reentry capsule having a segment of a sphere as the bottom. For the experimental portion of the investigation, a 1/12-scale model capsule and a full-scale capsule were tested for nominal flight paths of 65 deg and 90 deg (vertical), a range of contact attitudes from -30 deg to 30 deg, and a full-scale vertical velocity of 30 feet per second at contact. Accelerations were measured by accelerometers installed at the centers of gravity of the model and full-scale capsules. For the model test the accelerations were measured along the X-axis (roll) and Z-axis (yaw) and for the full-scale test they were measured along the X-axis (roll), Y-axis (pitch), and Z-axis (yaw). Motions and displacements of the capsules that occurred after contact were determined from high-speed motion pictures. The theoretical investigation was conducted to determine the accelerations that might occur along the X-axis when the capsule contacted the water from a 90 deg flight path at a 0 deg attitude. Assuming a rigid body, computations were made from equations obtained by utilizing the principle of the conservation of momentum. The agreement among data obtained from the model test, the full-scale test, and the theory was very good. The accelerations along the X-axis, for a vertical flight path and 0 deg attitude, were in the order of 40g. For a 65 deg flight path and 0 deg attitude, the accelerations along the X-axis were in the order of 50g. Changes in contact attitude, in either the positive or negative direction from 0 deg attitude, considerably reduced the magnitude of the accelerations measured along the X-axis. Accelerations measured along the Y- and Z-axes were relatively small at all test conditions. [Entire movie available on DVD from CASI as Doc ID 20070030955. Contact help@sti.nasa.gov

  10. Cryptococcus neoformans Intracellular Proliferation and Capsule Size Determines Early Macrophage Control of Infection.

    PubMed

    Bojarczuk, Aleksandra; Miller, Katie A; Hotham, Richard; Lewis, Amy; Ogryzko, Nikolay V; Kamuyango, Alfred A; Frost, Helen; Gibson, Rory H; Stillman, Eleanor; May, Robin C; Renshaw, Stephen A; Johnston, Simon A

    2016-01-01

    Cryptococcus neoformans is a significant fungal pathogen of immunocompromised patients. Many questions remain regarding the function of macrophages in normal clearance of cryptococcal infection and the defects present in uncontrolled cryptococcosis. Two current limitations are: 1) The difficulties in interpreting studies using isolated macrophages in the context of the progression of infection, and 2) The use of high resolution imaging in understanding immune cell behavior during animal infection. Here we describe a high-content imaging method in a zebrafish model of cryptococcosis that permits the detailed analysis of macrophage interactions with C. neoformans during infection. Using this approach we demonstrate that, while macrophages are critical for control of C. neoformans, a failure of macrophage response is not the limiting defect in fatal infections. We find phagocytosis is restrained very early in infection and that increases in cryptococcal number are driven by intracellular proliferation. We show that macrophages preferentially phagocytose cryptococci with smaller polysaccharide capsules and that capsule size is greatly increased over twenty-four hours of infection, a change that is sufficient to severely limit further phagocytosis. Thus, high-content imaging of cryptococcal infection in vivo demonstrates how very early interactions between macrophages and cryptococci are critical in the outcome of cryptococcosis. PMID:26887656

  11. Cryptococcus neoformans Intracellular Proliferation and Capsule Size Determines Early Macrophage Control of Infection

    PubMed Central

    Bojarczuk, Aleksandra; Miller, Katie A.; Hotham, Richard; Lewis, Amy; Ogryzko, Nikolay V.; Kamuyango, Alfred A.; Frost, Helen; Gibson, Rory H.; Stillman, Eleanor; May, Robin C.; Renshaw, Stephen A.; Johnston, Simon A.

    2016-01-01

    Cryptococcus neoformans is a significant fungal pathogen of immunocompromised patients. Many questions remain regarding the function of macrophages in normal clearance of cryptococcal infection and the defects present in uncontrolled cryptococcosis. Two current limitations are: 1) The difficulties in interpreting studies using isolated macrophages in the context of the progression of infection, and 2) The use of high resolution imaging in understanding immune cell behavior during animal infection. Here we describe a high-content imaging method in a zebrafish model of cryptococcosis that permits the detailed analysis of macrophage interactions with C. neoformans during infection. Using this approach we demonstrate that, while macrophages are critical for control of C. neoformans, a failure of macrophage response is not the limiting defect in fatal infections. We find phagocytosis is restrained very early in infection and that increases in cryptococcal number are driven by intracellular proliferation. We show that macrophages preferentially phagocytose cryptococci with smaller polysaccharide capsules and that capsule size is greatly increased over twenty-four hours of infection, a change that is sufficient to severely limit further phagocytosis. Thus, high-content imaging of cryptococcal infection in vivo demonstrates how very early interactions between macrophages and cryptococci are critical in the outcome of cryptococcosis. PMID:26887656

  12. Mutation in fucose synthesis gene of Klebsiella pneumoniae affects capsule composition and virulence in mice.

    PubMed

    Pan, Po-Chang; Chen, Hui-Wen; Wu, Po-Kuan; Wu, Yu-Yang; Lin, Chun-Hung; Wu, June H

    2011-02-01

    The emerging pathogenicity of Klebsiella pneumoniae (KP) is evident by the increasing number of clinical cases of liver abscess (LA) due to KP infection. A unique property of KP is its thick mucoid capsule. The bacterial capsule has been found to contain fucose in KP strains causing LA but not in those causing urinary tract infections. The products of the gmd and wcaG genes are responsible for converting mannose to fucose in KP. A KP strain, KpL1, which is known to have a high death rate in infected mice, was mutated by inserting an apramycin-resistance gene into the gmd. The mutant expressed genes upstream and downstream of gmd, but not gmd itself, as determined by reverse transcriptase polymerase chain reaction. The DNA mapping confirmed the disruption of the gmd gene. This mutant decreased its ability to kill infected mice and showed decreased virulence in infected HepG2 cells. Compared with wild-type KpL1, the gmd mutant lost fucose in capsular polysaccharides, increased biofilm formation and interacted more readily with macrophages. The mutant displayed morphological changes with long filament forms and less uniform sizes. The mutation also converted the serotype from K1 of wild-type to K2 and weak K3. The results indicate that disruption of the fucose synthesis gene affected the pathophysiology of this bacterium and may be related to the virulence of this KpL1 strain.

  13. Polysaccharides and bacterial plugging. [Leuconostoc bacteria

    SciTech Connect

    Fogler, H.S.

    1992-01-01

    The objectives of this research are to elucidate and model bacterial transport in porous media, to determine the importance of polysaccharides bridging as a retentive mechanism, and to identify key parameters that influence porous media plugging. This project has been subdivided into three tasks: Task 1 is the determination of the growth kinetics of the Leuconostoc bacteria and how they are affected by (1) the nutrient feed, and (2) surface effects; Task 2 will quantify the importance of polysaccharide production as a cell retention mechanism; and Task 3 is the elucidation of the rate of polysaccharide production and the combined effect that polysaccharide production and cell growth has upon plugging. Batch growth experiments have been conducted to determine the rate of cell growth, polymer production and nutrient consumption. The data from these experiments are currently being reduced to aid the development of an overall growth model.

  14. Mass Spectrometry of Intact Membrane Protein Complexes

    PubMed Central

    Laganowsky, Arthur; Reading, Eamonn; Hopper, Jonathan T.S.; Robinson, Carol V.

    2014-01-01

    Mass spectrometry of intact soluble protein complexes has emerged as a powerful technique to study the stoichiometry, structure-function and dynamics of protein assemblies. Recent developments have extended this technique to the study of membrane protein complexes where it has already revealed subunit stoichiometries and specific phospholipid interactions. Here, we describe a protocol for mass spectrometry of membrane protein complexes. The protocol begins with preparation of the membrane protein complex enabling not only the direct assessment of stoichiometry, delipidation, and quality of the target complex, but also evaluation of the purification strategy. A detailed list of compatible non-ionic detergents is included, along with a protocol for screening detergents to find an optimal one for mass spectrometry, biochemical and structural studies. This protocol also covers the preparation of lipids for protein-lipid binding studies and includes detailed settings for a Q-ToF mass spectrometer after introduction of complexes from gold-coated nanoflow capillaries. PMID:23471109

  15. Protein methylation reactions in intact pea chloroplasts

    SciTech Connect

    Niemi, K.J. )

    1989-04-01

    Post-translational protein methylation was investigated in Pisum sativum chloroplasts. Intact pea chloroplasts were incubated with ({sup 3}H-methyl)-S-adenosylmethionine under various conditions. The chloroplasts were then separated into stromal and thylakoid fractions and analyzed for radioactivity transferred to protein. Light enhanced the magnitude of labeling in both fractions. One thylakoid polypeptide with an apparent molecular mass of 43 kDa was labeled only in the light. Several other thylakoid and stromal proteins were labeled in both light and dark-labeling conditions. Both base-labile methylation, carboxy-methylesters and base-stable groups, N-methylations were found. Further characterization of the methyl-transfer reactions will be presented.

  16. Drilling to gabbro in intact ocean crust.

    PubMed

    Wilson, Douglas S; Teagle, Damon A H; Alt, Jeffrey C; Banerjee, Neil R; Umino, Susumu; Miyashita, Sumio; Acton, Gary D; Anma, Ryo; Barr, Samantha R; Belghoul, Akram; Carlut, Julie; Christie, David M; Coggon, Rosalind M; Cooper, Kari M; Cordier, Carole; Crispini, Laura; Durand, Sedelia Rodriguez; Einaudi, Florence; Galli, Laura; Gao, Yongjun; Geldmacher, Jörg; Gilbert, Lisa A; Hayman, Nicholas W; Herrero-Bervera, Emilio; Hirano, Nobuo; Holter, Sara; Ingle, Stephanie; Jiang, Shijun; Kalberkamp, Ulrich; Kerneklian, Marcie; Koepke, Jürgen; Laverne, Christine; Vasquez, Haroldo L Lledo; Maclennan, John; Morgan, Sally; Neo, Natsuki; Nichols, Holly J; Park, Sung-Hyun; Reichow, Marc K; Sakuyama, Tetsuya; Sano, Takashi; Sandwell, Rachel; Scheibner, Birgit; Smith-Duque, Chris E; Swift, Stephen A; Tartarotti, Paola; Tikku, Anahita A; Tominaga, Masako; Veloso, Eugenio A; Yamasaki, Toru; Yamazaki, Shusaku; Ziegler, Christa

    2006-05-19

    Sampling an intact sequence of oceanic crust through lavas, dikes, and gabbros is necessary to advance the understanding of the formation and evolution of crust formed at mid-ocean ridges, but it has been an elusive goal of scientific ocean drilling for decades. Recent drilling in the eastern Pacific Ocean in Hole 1256D reached gabbro within seismic layer 2, 1157 meters into crust formed at a superfast spreading rate. The gabbros are the crystallized melt lenses that formed beneath a mid-ocean ridge. The depth at which gabbro was reached confirms predictions extrapolated from seismic experiments at modern mid-ocean ridges: Melt lenses occur at shallower depths at faster spreading rates. The gabbros intrude metamorphosed sheeted dikes and have compositions similar to the overlying lavas, precluding formation of the cumulate lower oceanic crust from melt lenses so far penetrated by Hole 1256D.

  17. Drilling to gabbro in intact ocean crust.

    PubMed

    Wilson, Douglas S; Teagle, Damon A H; Alt, Jeffrey C; Banerjee, Neil R; Umino, Susumu; Miyashita, Sumio; Acton, Gary D; Anma, Ryo; Barr, Samantha R; Belghoul, Akram; Carlut, Julie; Christie, David M; Coggon, Rosalind M; Cooper, Kari M; Cordier, Carole; Crispini, Laura; Durand, Sedelia Rodriguez; Einaudi, Florence; Galli, Laura; Gao, Yongjun; Geldmacher, Jörg; Gilbert, Lisa A; Hayman, Nicholas W; Herrero-Bervera, Emilio; Hirano, Nobuo; Holter, Sara; Ingle, Stephanie; Jiang, Shijun; Kalberkamp, Ulrich; Kerneklian, Marcie; Koepke, Jürgen; Laverne, Christine; Vasquez, Haroldo L Lledo; Maclennan, John; Morgan, Sally; Neo, Natsuki; Nichols, Holly J; Park, Sung-Hyun; Reichow, Marc K; Sakuyama, Tetsuya; Sano, Takashi; Sandwell, Rachel; Scheibner, Birgit; Smith-Duque, Chris E; Swift, Stephen A; Tartarotti, Paola; Tikku, Anahita A; Tominaga, Masako; Veloso, Eugenio A; Yamasaki, Toru; Yamazaki, Shusaku; Ziegler, Christa

    2006-05-19

    Sampling an intact sequence of oceanic crust through lavas, dikes, and gabbros is necessary to advance the understanding of the formation and evolution of crust formed at mid-ocean ridges, but it has been an elusive goal of scientific ocean drilling for decades. Recent drilling in the eastern Pacific Ocean in Hole 1256D reached gabbro within seismic layer 2, 1157 meters into crust formed at a superfast spreading rate. The gabbros are the crystallized melt lenses that formed beneath a mid-ocean ridge. The depth at which gabbro was reached confirms predictions extrapolated from seismic experiments at modern mid-ocean ridges: Melt lenses occur at shallower depths at faster spreading rates. The gabbros intrude metamorphosed sheeted dikes and have compositions similar to the overlying lavas, precluding formation of the cumulate lower oceanic crust from melt lenses so far penetrated by Hole 1256D. PMID:16627698

  18. Polysaccharides and virulence of Burkholderia pseudomallei.

    PubMed

    Sarkar-Tyson, M; Thwaite, J E; Harding, S V; Smither, S J; Oyston, P C F; Atkins, T P; Titball, R W

    2007-08-01

    Burkholderia pseudomallei is the causative agent of melioidosis, an infectious disease of humans and animals. Gene clusters which encode capsular polysaccharide (type I O-PS) and LPS (type II O-PS), both of which play roles in virulence, have previously been identified. Here, the identification of two further putative clusters, type III O-PS and type IV O-PS, is reported. Mice challenged with type III O-PS or type IV O-PS mutants showed increased mean times to death (7.8 and 11.6 days) compared to those challenged with wild-type B. pseudomallei (3 days). To investigate the possible roles of polysaccharides in protection, mice were immunized with killed cells of wild-type B. pseudomallei or killed cells of B. pseudomallei with mutations in the O antigen, capsular polysaccharide, type III O-PS or type IV O-PS gene clusters. Immunization with all polysaccharide mutant strains resulted in delayed time to death compared to the naïve controls, following challenge with wild-type B. pseudomallei strain K96243. However, immunization with killed polysaccharide mutant strains conferred different degrees of protection, demonstrating the immunological importance of the polysaccharide clusters on the surface of B. pseudomallei.

  19. Monoclonal antibodies against plant cell wall polysaccharides

    SciTech Connect

    Hahn, M.G.; Bucheli, E.; Darvill, A.; Albersheim, P. )

    1989-04-01

    Monoclonal antibodies (McAbs) are useful tools to probe the structure of plant cell wall polysaccharides and to localize these polysaccharides in plant cells and tissues. Murine McAbs were generated against the pectic polysaccharide, rhamnogalacturonan I (RG-I), isolated from suspension-cultured sycamore cells. The McAbs that were obtained were grouped into three classes based upon their reactivities with a variety of plant polysaccharides and membrane glycoproteins. Eleven McAbs (Class I) recognize epitope(s) that appear to be immunodominant and are found in RG-I from sycamore and maize, citrus pectin, polygalacturonic acid, and membrane glycoproteins from suspension-cultured cells of sycamore, maize, tobacco, parsley, and soybean. A second group of five McAbs (Class II) recognize epitope(s) present in sycamore RG-I, but do not bind to any of the other polysaccharides or glycoproteins recognized by Class I. Lastly, one McAb (Class III) reacts with sycamore RG-I, sycamore and tamarind xyloglucan, and sycamore and rice glucuronoarabinoxylan, but does not bind to maize RG-I, polygalacturonic acid or the plant membrane glycoproteins recognized by Class I. McAbs in Classes II and III are likely to be useful in studies of the structure, biosynthesis and localization of plant cell wall polysaccharides.

  20. Functional expression of the capsule polymerase of Neisseria meningitidis serogroup X: a new perspective for vaccine development.

    PubMed

    Fiebig, Timm; Berti, Francesco; Freiberger, Friedrich; Pinto, Vittoria; Claus, Heike; Romano, Maria Rosaria; Proietti, Daniela; Brogioni, Barbara; Stummeyer, Katharina; Berger, Monika; Vogel, Ulrich; Costantino, Paolo; Gerardy-Schahn, Rita

    2014-02-01

    Neisseria meningitidis (Nm) is a leading cause of bacterial meningitis and sepsis. A key feature in pathogenicity is the capsular polysaccharide (CPS) that prevents complement activation and thus supports bacterial survival in the host. Twelve serogroups characterized by immunologically and structurally different CPSs have been identified. Meningococcal CPSs elicit bactericidal antibodies and consequently are used for the development of vaccines. Vaccination against the epidemiologically most relevant serogroups was initially carried out with purified CPS and later followed by conjugate vaccines which consist of CPS covalently linked to a carrier protein. Of increasing importance in the African meningitis belt is NmX for which no vaccine is currently available. Here, we describe the molecular cloning, recombinant expression and purification of the capsule polymerase (CP) of NmX called CsxA. The protein expressed with N- and/or C-terminal epitope tags was soluble and could be purified to near homogeneity. With short oligosaccharide primers derived from the NmX capsular polysaccharide (CPSX), recombinant CsxA produced long polymer chains in vitro that in immunoblots were detected with NmX-specific antibodies. Moreover, the chemical identity of in vitro produced NmX polysaccharides was confirmed by NMR. Besides the demonstration that the previously identified gene csxA encodes the NmX CP CsxA, the data presented in this study pave the way for the use of the recombinant CP as a safe and economic way to generate the CPSX in vaccine developmental programs.

  1. Effects of pulse shape on indirect drive ICF capsule robustness

    NASA Astrophysics Data System (ADS)

    Fetterman, Abe; Haan, Steve; Herrmann, Mark; Salmonson, Jay; Marinak, Michael

    2004-11-01

    The pulse shape incident on an ICF capsule plays an important role in determining the capsule's performance. Keeping the capsule on a low adiabat maximizes its compressibility and reduces the energy required for ignition. However, 2D studies of direct drive designs suggest that capsules with high adiabats are more robust with respect to the growth of perturbations than capsules with lower adiabats. The question arises, what is the optimal adiabat and pulse shape for an indirect drive inertial confinement fusion capsule? Is there any advantage in having the adiabat above the absolute minimum? To answer these questions we have developed an automated pulse shaper for the HYDRA computer codefootnote[2]Marinak, M. M. et. al. ``Three-dimensional HYDRA simulations of National Ignition Facility targets'' Phys. Plasmas 8, 2275 (2001). and used it to study the sensitivity of indirect drive capsules to various pulse shapes.

  2. Viscoelastic properties of levan polysaccharides

    NASA Astrophysics Data System (ADS)

    Noll, Kenneth; Rende, Deniz; Ozisik, Rahmi; Toksoy-Oner, Ebru

    2014-03-01

    Levan is a naturally occurring polysaccharide that is composed of β-D-fructofuranose units with β(2-6) linkages between fructose rings. It is synthesized by the action of a secreted levansucrase (EC 2.4.1.10) that converts sucrose into the levan externally (exopolysaccharide). Levan is a homopolysaccharide that is non-toxic, water soluble,, and has anti-tumor activity and low immunological response. Therefore, levan presents great potential to be used as a novel functional biopolymer in foods, feeds, cosmetics, pharmaceutical and chemical industries. Despite these favorable properties, levan has a moderately low mechanical properties and poor film forming capability. In the current study, the agglomeration behavior of levan in water and in saline solutions was investigated at 298 and 310 K by dynamic light scattering and transmission electron microscopy (TEM). The viscoelastic properties of neat and oxidized levan films were studied via nanoindentation experiments in the quasi-static and dynamic modes The material is partially based upon work supported by NSF under Grant Nos. 1200270 and 1003574, and TUBITAK 111M232.

  3. PssP2 Is a Polysaccharide Co-Polymerase Involved in Exopolysaccharide Chain-Length Determination in Rhizobium leguminosarum

    PubMed Central

    Marczak, Małgorzata; Matysiak, Paulina; Kutkowska, Jolanta; Skorupska, Anna

    2014-01-01

    Production of extracellular polysaccharides is a complex process engaging proteins localized in different subcellular compartments, yet communicating with each other or even directly interacting in multicomponent complexes. Proteins involved in polymerization and transport of exopolysaccharide (EPS) in Rhizobium leguminosarum are encoded within the chromosomal Pss-I cluster. However, genes implicated in polysaccharide synthesis are common in rhizobia, with several homologues of pss genes identified in other regions of the R. leguminosarum genome. One such region is chromosomally located Pss-II encoding proteins homologous to known components of the Wzx/Wzy-dependent polysaccharide synthesis and transport systems. The pssP2 gene encodes a protein similar to polysaccharide co-polymerases involved in determination of the length of polysaccharide chains in capsule and O-antigen biosynthesis. In this work, a mutant with a disrupted pssP2 gene was constructed and its capabilities to produce EPS and enter into a symbiotic relationship with clover were studied. The pssP2 mutant, while not altered in lipopolysaccharide (LPS), displayed changes in molecular mass distribution profile of EPS. Lack of the full-length PssP2 protein resulted in a reduction of high molecular weight EPS, yet polymerized to a longer length than in the RtTA1 wild type. The mutant strain was also more efficient in symbiotic performance. The functional interrelation between PssP2 and proteins encoded within the Pss-I region was further supported by data from bacterial two-hybrid assays providing evidence for PssP2 interactions with PssT polymerase, as well as glycosyltransferase PssC. A possible role for PssP2 in a complex involved in EPS chain-length determination is discussed. PMID:25268738

  4. Capsule- and disk-filter procedure

    USGS Publications Warehouse

    Skrobialowski, Stanley C.

    2016-01-01

    Capsule and disk filters are disposable, self-contained units composed of a pleated or woven filter medium encased in a polypropylene or other plastic housing that can be connected inline to a sample-delivery system (such as a submersible or peristaltic pump) that generates sufficient pressure (positive or negative) to force water through the filter. Filter media are available in several pore sizes, but 0.45 µm is the pore size used routinely for most studies at this time. Capsule or disk filters (table 5.2.1.A.1) are required routinely for most studies when filtering samples for trace-element analyses and are recommended when filtering samples for major-ion or other inorganic-constituent analyses.

  5. Polymeric multilayer capsules in drug delivery.

    PubMed

    De Cock, Liesbeth J; De Koker, Stefaan; De Geest, Bruno G; Grooten, Johan; Vervaet, Chris; Remon, Jean Paul; Sukhorukov, Gleb B; Antipina, Maria N

    2010-09-17

    Recent advances in medicine and biotechnology have prompted the need to develop nanoengineered delivery systems that can encapsulate a wide variety of novel therapeutics such as proteins, chemotherapeutics, and nucleic acids. Moreover, these delivery systems should be "intelligent", such that they can deliver their payload at a well-defined time, place, or after a specific stimulus. Polymeric multilayer capsules, made by layer-by-layer (LbL) coating of a sacrificial template followed by dissolution of the template, allow the design of microcapsules in aqueous conditions by using simple building blocks and assembly procedures, and provide a previously unmet control over the functionality of the microcapsules. Polymeric multilayer capsules have recently received increased interest from the life science community, and many interesting systems have appeared in the literature with biodegradable components and biospecific functionalities. In this Review we give an overview of the recent breakthroughs in their application for drug delivery.

  6. Electroformation of Janus and patchy capsules

    PubMed Central

    Rozynek, Zbigniew; Mikkelsen, Alexander; Dommersnes, Paul; Fossum, Jon Otto

    2014-01-01

    Janus and patchy particles have designed heterogeneous surfaces that consist of two or several patches with different materials properties. These particles are emerging as building blocks for a new class of soft matter and functional materials. Here we introduce a route for forming heterogeneous capsules by producing highly ordered jammed colloidal shells of various shapes with domains of controlled size and composition. These structures combine the functionalities offered by Janus or patchy particles, and those given by permeable shells such as colloidosomes. The simple assembly route involves the synergetic action of electro-hydrodynamic flow and electro-coalescence. We demonstrate that the method is robust and straightforwardly extendable to production of multi-patchy capsules. This forms a starting point for producing patchy colloidosomes with domains of anisotropic chemical surface properties, permeability or mixed liquid–solid phase domains, which could be exploited to produce functional emulsions, light and hollow supra-colloidosome structures, or scaffolds. PMID:24853057

  7. Teaching basic neurophysiology using intact earthworms.

    PubMed

    Kladt, Nikolay; Hanslik, Ulrike; Heinzel, Hans-Georg

    2010-01-01

    Introductory neurobiology courses face the problem that practical exercises often require expensive equipment, dissections, and a favorable student-instructor ratio. Furthermore, the duration of an experiment might exceed available time or the level of required expertise is too high to successfully complete the experiment. As a result, neurobiological experiments are commonly replaced by models and simulations, or provide only very basic experiments, such as the frog sciatic nerve preparation, which are often time consuming and tedious. Action potential recordings in giant fibers of intact earthworms (Lumbricus terrestris) circumvent many of these problems and result in a nearly 100% success rate. Originally, these experiments were introduced as classroom exercises by Charles Drewes in 1978 using awake, moving earthworms. In 1990, Hans-Georg Heinzel described further experiments using anesthetized earthworms. In this article, we focus on the application of these experiments as teaching tools for basic neurobiology courses. We describe and extend selected experiments, focusing on specific neurobiological principles with experimental protocols optimized for classroom application. Furthermore, we discuss our experience using these experiments in animal physiology and various neurobiology courses at the University of Bonn. PMID:23494516

  8. Capsule endoscopy: Present status and future expectation

    PubMed Central

    Goenka, Mahesh K; Majumder, Shounak; Goenka, Usha

    2014-01-01

    Video capsule endoscopy (CE) since its introduction 13 years back, has revolutionized our approach to small intestinal diseases. Obscure gastrointestinal bleed (OGIB) continues to be the most important indication for CE with a high sensitivity, specificity as well as positive and negative predictive values. It is best performed during ongoing bleed or immediately thereafter. Overt OGIB has a higher diagnostic yield than occult OGIB. However, even in iron deficiency anemia, CE is emerging as important investigation after initial negative work up. In suspected Crohn’s disease (CD), CE has been shown superior to traditional imaging and endoscopic technique and should be considered after a negative ileocolonoscopy. Although CE has also been used for evaluating established CD, a high capsule retention rate precludes its use ahead of cross-sectional imaging. Celiac disease, particularly where gastro-duodenoscopy cannot be performed or is normal, can also be investigated by CE. Small bowel tumor, hereditary polyposis syndrome, and non-steroidal anti-inflammatory drugs induced intestinal damage are other indications for CE. Capsule retention is the only significant adverse outcome of CE and occurs mostly in presence of intestinal obstruction. This can be prevented by use of Patency capsule prior to CE examination. Presence of cardiac pacemaker and intracardiac devices continue to be relative contraindications for CE, though data do not suggest interference of CE with these devices. Major limitations of CE today include failure to control its movement from outside, inability of CE to acquire tissue for diagnosis, and lack of therapeutic help. With ongoing interesting and exciting developments taking place in these areas, these issues would be solved in all probability in near future. CE has the potential to become one of the most important tools in diagnostic and possibly in the therapeutic field of gastrointestinal disorder. PMID:25110430

  9. Capsule endoscopy: Present status and future expectation.

    PubMed

    Goenka, Mahesh K; Majumder, Shounak; Goenka, Usha

    2014-08-01

    Video capsule endoscopy (CE) since its introduction 13 years back, has revolutionized our approach to small intestinal diseases. Obscure gastrointestinal bleed (OGIB) continues to be the most important indication for CE with a high sensitivity, specificity as well as positive and negative predictive values. It is best performed during ongoing bleed or immediately thereafter. Overt OGIB has a higher diagnostic yield than occult OGIB. However, even in iron deficiency anemia, CE is emerging as important investigation after initial negative work up. In suspected Crohn's disease (CD), CE has been shown superior to traditional imaging and endoscopic technique and should be considered after a negative ileocolonoscopy. Although CE has also been used for evaluating established CD, a high capsule retention rate precludes its use ahead of cross-sectional imaging. Celiac disease, particularly where gastro-duodenoscopy cannot be performed or is normal, can also be investigated by CE. Small bowel tumor, hereditary polyposis syndrome, and non-steroidal anti-inflammatory drugs induced intestinal damage are other indications for CE. Capsule retention is the only significant adverse outcome of CE and occurs mostly in presence of intestinal obstruction. This can be prevented by use of Patency capsule prior to CE examination. Presence of cardiac pacemaker and intracardiac devices continue to be relative contraindications for CE, though data do not suggest interference of CE with these devices. Major limitations of CE today include failure to control its movement from outside, inability of CE to acquire tissue for diagnosis, and lack of therapeutic help. With ongoing interesting and exciting developments taking place in these areas, these issues would be solved in all probability in near future. CE has the potential to become one of the most important tools in diagnostic and possibly in the therapeutic field of gastrointestinal disorder. PMID:25110430

  10. Enteric-coated capsule containing β-galactosidase-loaded polylactic acid nanocapsules: enzyme stability and milk lactose hydrolysis under simulated gastrointestinal conditions.

    PubMed

    He, Hongjun; Zhang, Xueting; Sheng, Yan

    2014-11-01

    In order to protect peroral β-galactosidase from being degraded and hydrolyse milk lactose efficiently in the environments of gastrointestinal tract, a double-capsule delivery system composed of enteric-coated capsule and polylactic acid (PLA) nanocapsules (NCs) was developed for encapsulation of β-galactosidase. β-galactosidase-loaded PLA NCs in the size range of 100-200 nm were prepared by a modified w1/o/w2 technique. During the encapsulation process, dichloromethane/ethyl acetate (1 : 1, v/v) as the solvent composition, high-pressure homogenisation (150 bar, 3 min) as the second emulsification method and polyvinyl alcohol or Poloxamer 188 as a stabiliser in the inner phase could efficiently improve the activity retention of β-galactosidase (>90%). Subsequently, the prepared NCs were freeze-dried and filled in a hydroxypropyl methylcellulose phthalate (HP55)-coated capsule. In vitro results revealed that the HP55-coated capsule remained intact in the simulated gastric fluid and efficiently protected the nested β-galactosidase from acidic denaturation. Under the simulated intestinal condition, the enteric coating dissolved rapidly and released the β-galactosidase-loaded PLA NCs, which exhibited greater stability against enzymatic degradation and higher hydrolysis ratio (∼100%) towards milk lactose than the free β-galactosidase. These results suggest that this double-capsule delivery system represents promising candidate for efficient lactose hydrolysis in the gastrointestinal tract.

  11. Aerodynamics for the Mars Phoenix Entry Capsule

    NASA Technical Reports Server (NTRS)

    Edquist, Karl T.; Desai, Prasun N.; Schoenenberger, Mark

    2008-01-01

    Pre-flight aerodynamics data for the Mars Phoenix entry capsule are presented. The aerodynamic coefficients were generated as a function of total angle-of-attack and either Knudsen number, velocity, or Mach number, depending on the flight regime. The database was constructed using continuum flowfield computations and data from the Mars Exploration Rover and Viking programs. Hypersonic and supersonic static coefficients were derived from Navier-Stokes solutions on a pre-flight design trajectory. High-altitude data (free-molecular and transitional regimes) and dynamic pitch damping characteristics were taken from Mars Exploration Rover analysis and testing. Transonic static coefficients from Viking wind tunnel tests were used for capsule aerodynamics under the parachute. Static instabilities were predicted at two points along the reference trajectory and were verified by reconstructed flight data. During the hypersonic instability, the capsule was predicted to trim at angles as high as 2.5 deg with an on-axis center-of-gravity. Trim angles were predicted for off-nominal pitching moment (4.2 deg peak) and a 5 mm off-axis center-ofgravity (4.8 deg peak). Finally, hypersonic static coefficient sensitivities to atmospheric density were predicted to be within uncertainty bounds.

  12. High-speed precision weighing of pharmaceutical capsules

    NASA Astrophysics Data System (ADS)

    Bürmen, Miran; Pernuš, Franjo; Likar, Boštjan

    2009-11-01

    In this paper, we present a cost-effective method for fast and accurate in-line weighing of hard gelatin capsules based on the optimized capacitance sensor and real-time processing of the capsule capacitance profile resulting from 5000 capacitance measurements per second. First, the effect of the shape and size of the capacitive sensor on the sensitivity and stability of the measurements was investigated in order to optimize the performance of the system. The method was tested on two types of hard gelatin capsules weighing from 50 mg to 650 mg. The results showed that the capacitance profile was exceptionally well correlated with the capsule weight with the correlation coefficient exceeding 0.999. The mean precision of the measurements was in the range from 1 mg to 3 mg, depending on the size of the capsule and was significantly lower than the 5% weight tolerances usually used by the pharmaceutical industry. Therefore, the method was found feasible for weighing pharmaceutical hard gelatin capsules as long as certain conditions are met regarding the capsule fill properties and environment stability. The proposed measurement system can be calibrated by using only two or three sets of capsules with known weight. However, for most applications it is sufficient to use only empty and nominally filled capsules for calibration. Finally, a practical application of the proposed method showed that a single system is capable of weighing around 75 000 capsules per hour, while using multiple systems could easily increase the inspection rate to meet almost any requirements.

  13. Capsular Polysaccharide of Erysipelothrix rhusiopathiae, the Causative Agent of Swine Erysipelas, and Its Modification with Phosphorylcholine

    PubMed Central

    Shi, Fang; Harada, Tomoyuki; Ogawa, Yohsuke; Ono, Hiroshi; Ohnishi-Kameyama, Mayumi; Miyamoto, Toru; Eguchi, Masahiro

    2012-01-01

    The capsule has been implicated in the virulence of the swine pathogen Erysipelothrix rhusiopathiae, a rod-shaped, intracellular Gram-positive bacterium that has a unique phylogenetic position in the phylum Firmicutes and is a close relative of Mollicutes (mycoplasma species). In this study, we analyzed the genetic locus and composition of the capsular polysaccharide (CPS) of the Fujisawa strain of E. rhusiopathiae. Genome analysis of the Fujisawa strain revealed that the genetic locus for capsular polysaccharide synthesis (cps) is located next to an lic operon, which is involved in the incorporation and expression of phosphorylcholine (PCho). Reverse transcription-PCR analysis showed that cps and lic are transcribed as a single mRNA, indicating that the loci form an operon. Using the cell surface antigen-specific monoclonal antibody (MAb) ER21 as a probe, the capsular materials were isolated from the Fujisawa strain by hot water extraction and treatment with DNase, RNase, pronase, and N-acetylmuramidase SG, followed by anion-exchange and gel filtration chromatography. The materials were then analyzed by high-performance liquid chromatography, mass spectrometry, and nuclear magnetic resonance (NMR) spectroscopy. The CPS of E. rhusiopathiae is heterogeneous and consists of the major monosaccharides galacturonic acid, galactose, mannose, glucose, arabinose, xylose, and N-acetylglucosamine and some minor monosaccharides containing ribose, rhamnose, and N-acetylgalactosamine. In addition, the capsule is modified by PCho, which comigrates with the capsular materials, as determined by Western immunoblotting, and colocalizes on the cell surface, as determined by immunogold electron microscopy. Virulence testing of PCho-defective mutants in mice demonstrated that PCho is critical for the virulence of this organism. PMID:22949554

  14. Positive youth development, life satisfaction, and problem behaviors of adolescents in intact and non-intact families in Hong Kong.

    PubMed

    Shek, Daniel T L; Leung, Hildie

    2013-01-01

    This study investigated whether Chinese adolescents living in intact and non-intact families differed in their positive development, life satisfaction, and risk behavior. A total of 3,328 Secondary 1 students responded to measures of positive youth development (such as resilience and psychosocial competencies), life satisfaction, and risk behavior (substance abuse, delinquency, Internet addiction, consumption of pornographic materials, self-harm, and behavioral intention to engage in problem behavior). Findings revealed that adolescents growing up in intact families reported higher levels of positive developmental outcomes and life satisfaction as compared with adolescents from non-intact families. Adolescents in non-intact families also reported higher levels of risk behaviors than those growing up in intact families. PMID:24400264

  15. Positive Youth Development, Life Satisfaction, and Problem Behaviors of Adolescents in Intact and Non-Intact Families in Hong Kong

    PubMed Central

    Shek, Daniel T. L.; Leung, Hildie

    2013-01-01

    This study investigated whether Chinese adolescents living in intact and non-intact families differed in their positive development, life satisfaction, and risk behavior. A total of 3,328 Secondary 1 students responded to measures of positive youth development (such as resilience and psychosocial competencies), life satisfaction, and risk behavior (substance abuse, delinquency, Internet addiction, consumption of pornographic materials, self-harm, and behavioral intention to engage in problem behavior). Findings revealed that adolescents growing up in intact families reported higher levels of positive developmental outcomes and life satisfaction as compared with adolescents from non-intact families. Adolescents in non-intact families also reported higher levels of risk behaviors than those growing up in intact families. PMID:24400264

  16. The copper active site of CBM33 polysaccharide oxygenases.

    PubMed

    Hemsworth, Glyn R; Taylor, Edward J; Kim, Robbert Q; Gregory, Rebecca C; Lewis, Sally J; Turkenburg, Johan P; Parkin, Alison; Davies, Gideon J; Walton, Paul H

    2013-04-24

    The capacity of metal-dependent fungal and bacterial polysaccharide oxygenases, termed GH61 and CBM33, respectively, to potentiate the enzymatic degradation of cellulose opens new possibilities for the conversion of recalcitrant biomass to biofuels. GH61s have already been shown to be unique metalloenzymes containing an active site with a mononuclear copper ion coordinated by two histidines, one of which is an unusual τ-N-methylated N-terminal histidine. We now report the structural and spectroscopic characterization of the corresponding copper CBM33 enzymes. CBM33 binds copper with high affinity at a mononuclear site, significantly stabilizing the enzyme. X-band EPR spectroscopy of Cu(II)-CBM33 shows a mononuclear type 2 copper site with the copper ion in a distorted axial coordination sphere, into which azide will coordinate as evidenced by the concomitant formation of a new absorption band in the UV/vis spectrum at 390 nm. The enzyme's three-dimensional structure contains copper, which has been photoreduced to Cu(I) by the incident X-rays, confirmed by X-ray absorption/fluorescence studies of both aqueous solution and intact crystals of Cu-CBM33. The single copper(I) ion is ligated in a T-shaped configuration by three nitrogen atoms from two histidine side chains and the amino terminus, similar to the endogenous copper coordination geometry found in fungal GH61. PMID:23540833

  17. Analysis of the Protein Kinase A-Regulated Proteome of Cryptococcus neoformans Identifies a Role for the Ubiquitin-Proteasome Pathway in Capsule Formation

    PubMed Central

    Geddes, J. M. H.; Caza, M.; Croll, D.; Stoynov, N.; Foster, L. J.

    2016-01-01

    ABSTRACT The opportunistic fungal pathogen Cryptococcus neoformans causes life-threatening meningitis in immunocompromised individuals. The expression of virulence factors, including capsule and melanin, is in part regulated by the cyclic-AMP/protein kinase A (cAMP/PKA) signal transduction pathway. In this study, we investigated the influence of PKA on the composition of the intracellular proteome to obtain a comprehensive understanding of the regulation that underpins virulence. Through quantitative proteomics, enrichment and bioinformatic analyses, and an interactome study, we uncovered a pattern of PKA regulation for proteins associated with translation, the proteasome, metabolism, amino acid biosynthesis, and virulence-related functions. PKA regulation of the ubiquitin-proteasome pathway in C. neoformans showed a striking parallel with connections between PKA and protein degradation in chronic neurodegenerative disorders and other human diseases. Further investigation of proteasome function with the inhibitor bortezomib revealed an impact on capsule production as well as hypersusceptibility for strains with altered expression or activity of PKA. Parallel studies with tunicamycin also linked endoplasmic reticulum stress with capsule production and PKA. Taken together, the data suggest a model whereby expression of PKA regulatory and catalytic subunits and the activation of PKA influence proteostasis and the function of the endoplasmic reticulum to control the elaboration of the polysaccharide capsule. Overall, this study revealed both broad and conserved influences of the cAMP/PKA pathway on the proteome and identified proteostasis as a potential therapeutic target for the treatment of cryptococcosis. PMID:26758180

  18. The Crystal Structure of Escherichia coli Group 4 Capsule Protein GfcC Reveals a Domain Organization Resembling That of Wza

    SciTech Connect

    Sathiyamoorthy, Karthik; Mills, Erez; Franzmann, Titus M.; Rosenshine, Ilan; Saper, Mark A.

    2012-03-15

    We report the 1.9 {angstrom} resolution crystal structure of enteropathogenic Escherichia coli GfcC, a periplasmic protein encoded by the gfc operon, which is essential for assembly of group 4 polysaccharide capsule (O-antigen capsule). Presumed gene orthologs of gfcC are present in capsule-encoding regions of at least 29 genera of Gram-negative bacteria. GfcC, a member of the DUF1017 family, is comprised of tandem {beta}-grasp (ubiquitin-like) domains (D2 and D3) and a carboxyl-terminal amphipathic helix, a domain arrangement reminiscent of that of Wza that forms an exit pore for group 1 capsule export. Unlike the membrane-spanning C-terminal helix from Wza, the GfcC C-terminal helix packs against D3. Previously unobserved in a {beta}-grasp domain structure is a 48-residue helical hairpin insert in D2 that binds to D3, constraining its position and sequestering the carboxyl-terminal amphipathic helix. A centrally located and invariant Arg115 not only is essential for proper localization but also forms one of two mostly conserved pockets. Finally, we draw analogies between a GfcC protein fused to an outer membrane {beta}-barrel pore in some species and fusion proteins necessary for secreting biofilm-forming exopolysaccharides.

  19. Capsule of Streptococcus equi subsp. zooepidemicus hampers the adherence and invasion of epithelial and endothelial cells and is attenuated during internalization.

    PubMed

    Xu, Bin; Pei, Xiaomeng; Su, Yiqi; Ma, Zhe; Fan, Hongjie

    2016-08-01

    Direct interaction between pathogens and host cells often is a prerequisite for colonization, infection and dissemination. Regulated production of capsular polysaccharide (CPS), which is made of hyaluronic acid, is essential for the pathogenicity of Streptococcus equi subsp. Zooepidemicus (SEZ). Here, we constructed a CPS-deleted mutant and analyzed it along with the parental wild-type strain in attachment and invasion of mammalian epithelial and endothelial cell lines. The CPS-deleted mutant exhibited significant increase in adherence and invasion by several orders of magnitude compared with the wild-type strain through quantitative analysis and electron microscopy observation. After the wild-type strain was recovered from invaded cells, its morphology was analyzed by visual methods and scanning electron microscopy, which revealed that its capsule was almost completely absent. Capsule measurements showed a similar result in which CPS production was nearly attenuated to the same extent as in the CPS-deleted mutant. qPCR assays revealed a marked reduction in the transcriptional levels of the CPS biosynthesis genes, has operon. Moreover, the repression in capsular production was stable inheritance. Our findings indicate that SEZ is a facultative intracellular bacterium, capsule attenuation in SEZ contributes to attachment and invasion in interactions with host cells, and the active regulation of capsule breakdown is controlled by SEZ during internalization. PMID:27388015

  20. The crystal structure of Escherichia coli group 4 capsule protein GfcC reveals a domain organization resembling that of Wza.

    PubMed

    Sathiyamoorthy, Karthik; Mills, Erez; Franzmann, Titus M; Rosenshine, Ilan; Saper, Mark A

    2011-06-21

    We report the 1.9 Å resolution crystal structure of enteropathogenic Escherichia coli GfcC, a periplasmic protein encoded by the gfc operon, which is essential for assembly of group 4 polysaccharide capsule (O-antigen capsule). Presumed gene orthologs of gfcC are present in capsule-encoding regions of at least 29 genera of Gram-negative bacteria. GfcC, a member of the DUF1017 family, is comprised of tandem β-grasp (ubiquitin-like) domains (D2 and D3) and a carboxyl-terminal amphipathic helix, a domain arrangement reminiscent of that of Wza that forms an exit pore for group 1 capsule export. Unlike the membrane-spanning C-terminal helix from Wza, the GfcC C-terminal helix packs against D3. Previously unobserved in a β-grasp domain structure is a 48-residue helical hairpin insert in D2 that binds to D3, constraining its position and sequestering the carboxyl-terminal amphipathic helix. A centrally located and invariant Arg115 not only is essential for proper localization but also forms one of two mostly conserved pockets. Finally, we draw analogies between a GfcC protein fused to an outer membrane β-barrel pore in some species and fusion proteins necessary for secreting biofilm-forming exopolysaccharides. PMID:21449614

  1. Immobilized phosphorylase for synthesis of polysaccharides from glucose

    NASA Technical Reports Server (NTRS)

    Marshall, D. L.

    1972-01-01

    Continuous processes for enzymatic production of carbohydrates from glucose are discussed. Key reactant in process is identified as phosphorylase which catalyzes reversible formation or degradation of polysaccharide. Chemical compounds and reactions to synthesize polysaccharides are analyzed.

  2. Immunomodulatory effects of a polysaccharide from Tamarindus indica.

    PubMed

    Sreelekha, T T; Vijayakumar, T; Ankanthil, R; Vijayan, K K; Nair, M K

    1993-04-01

    A polysaccharide isolated and purified from Tamarindus indica shows immunomodulatory activities such as phagocytic enhancement, leukocyte migration inhibition and inhibition of cell proliferation. These properties suggest that this polysaccharide from T. indica may have some biological applications.

  3. Neisseria meningitidis serogroup A capsular polysaccharide acetyltransferase, methods and compositions

    DOEpatents

    Stephens, David S.; Gudlavalleti, Seshu K.; Tzeng, Yih-Ling; Datta, Anup K.; Carlson, Russell W.

    2011-02-08

    Provided are methods for recombinant production of an O-acetyltransferase and methods for acetylating capsular polysaccharides, especially those of a Serogroup A Neisseria meningitidis using the recombinant O-acetyltransferase, and immunogenic compositions comprising the acetylated capsular polysaccharide.

  4. Lifting the mask: identification of new small molecule inhibitors of uropathogenic Escherichia coli group 2 capsule biogenesis.

    PubMed

    Goller, Carlos C; Arshad, Mehreen; Noah, James W; Ananthan, Subramaniam; Evans, Carrie W; Nebane, N Miranda; Rasmussen, Lynn; Sosa, Melinda; Tower, Nichole A; White, E Lucile; Neuenswander, Benjamin; Porubsky, Patrick; Maki, Brooks E; Rogers, Steven A; Schoenen, Frank; Seed, Patrick C

    2014-01-01

    Uropathogenic Escherichia coli (UPEC) is the leading cause of community-acquired urinary tract infections (UTIs), with over 100 million UTIs occurring annually throughout the world. Increasing antimicrobial resistance among UPEC limits ambulatory care options, delays effective treatment, and may increase overall morbidity and mortality from complications such as urosepsis. The polysaccharide capsules of UPEC are an attractive target a therapeutic, based on their importance in defense against the host immune responses; however, the large number of antigenic types has limited their incorporation into vaccine development. The objective of this study was to identify small-molecule inhibitors of UPEC capsule biogenesis. A large-scale screening effort entailing 338,740 compounds was conducted in a cell-based, phenotypic screen for inhibition of capsule biogenesis in UPEC. The primary and concentration-response assays yielded 29 putative inhibitors of capsule biogenesis, of which 6 were selected for further studies. Secondary confirmatory assays identified two highly active agents, named DU003 and DU011, with 50% inhibitory concentrations of 1.0 µM and 0.69 µM, respectively. Confirmatory assays for capsular antigen and biochemical measurement of capsular sugars verified the inhibitory action of both compounds and demonstrated minimal toxicity and off-target effects. Serum sensitivity assays demonstrated that both compounds produced significant bacterial death upon exposure to active human serum. DU011 administration in mice provided near complete protection against a lethal systemic infection with the prototypic UPEC K1 isolate UTI89. This work has provided a conceptually new class of molecules to combat UPEC infection, and future studies will establish the molecular basis for their action along with efficacy in UTI and other UPEC infections.

  5. Ice nucleation activity of polysaccharides

    NASA Astrophysics Data System (ADS)

    Bichler, Magdalena; Felgitsch, Laura; Haeusler, Thomas; Seidl-Seiboth, Verena; Grothe, Hinrich

    2015-04-01

    Heterogeneous ice nucleation is an important process in the atmosphere. It shows direct impact on our climate by triggering ice cloud formation and therefore it has much influence on the radiation balance of our planet (Lohmann et al. 2002; Mishchenko et al. 1996). The process itself is not completely understood so far and many questions remain open. Different substances have been found to exhibit ice nucleation activity (INA). Due to their vast differences in chemistry and morphology it is difficult to predict what substance will make good ice nuclei and which will not. Hence simple model substances must be found and be tested regarding INA. Our work aims at gaining to a deeper understanding of heterogeneous ice nucleation. We intend to find some reference standards with defined chemistry, which may explain the mechanisms of heterogeneous ice nucleation. A particular focus lies on biological carbohydrates in regards to their INA. Biological carbohydrates are widely distributed in all kingdoms of life. Mostly they are specific for certain organisms and have well defined purposes, e.g. structural polysaccharides like chitin (in fungi and insects) and pectin (in plants), which has also water-binding properties. Since they are widely distributed throughout our biosphere and mostly safe to use for nutrition purposes, they are well studied and easily accessible, rendering them ideal candidates as proxies. In our experiments we examined various carbohydrates, like the already mentioned chitin and pectin, as well as their chemical modifications. Lohmann U.; A Glaciation Indirect Aerosol Effect Caused by Soot Aerosols; J. Geoph. Res.; Vol. 24 No.4; pp 11-1 - 11-4; 2002 Mishchenko M.I., Rossow W.B., Macke A., Lacis A. A.; Sensitivity of Cirrus Cloud Albedo, Bidirectional Reflectance and Optical Thickness Retrieval Accuracy to Ice Particle Shape, J. Geoph. Res.; Vol. 101, No D12; pp. 16,973 - 16,985; 1996

  6. Experimental serpentinization of intact dunite cores

    NASA Astrophysics Data System (ADS)

    Luhmann, A. J.; Tutolo, B. M.; Kong, X. Z.; Bagley, B. C.; Schaen, A. T.; Saar, M. O.; Seyfried, W. E., Jr.

    2014-12-01

    Serpentinization in ultramafic-hosted hydrothermal systems, such as Lost City, produces relatively cool and alkaline fluids that support diverse ecosystems. To simulate serpentinization in such systems, we conducted single-pass, flow-through experiments on dunite cores cut out of a sample from Jackson County, North Carolina. Experimental seawater prepared using laboratory-grade reagents and standards was pumped through a core at 150ºC and 150 bar pore-fluid outlet pressure at a flow rate of 0.01 ml/min. An additional experiment will be conducted at 200ºC. At 150ºC, permeability decreased by 2.3 times with reaction progress over the course of the 36 day experiment. Fluid-rock reaction generally produced CO2, H2, CH4, and CO concentrations of 100 μmol/kg, up to 40 μmol/kg, 2 μmol/kg, and less than 1 μmol/kg, respectively. Outlet fluid chemistry was relatively stable, except for initial peaks in Al, Ba, Fe, Mn, and Si. pH of outlet fluids increased with reaction progress, but it was always lower (6.9-7.4) than the initial seawater (7.8). X-ray computed tomography scans were/will be collected for both pre- and post-experimental cores. The combination of flow-through experiments on solid, intact rock cores cut out of natural samples and X-ray tomography permits visualization and quantification of mineralogical changes and flow path evolution during serpentinization. This approach further permits physical and chemical processes to be documented on a fine scale to better understand feedbacks between chemical reactions and flow fields, with implications for ultramafic-hosted hydrothermal systems.

  7. Motion of an elastic capsule in a square microfluidic channel.

    PubMed

    Kuriakose, S; Dimitrakopoulos, P

    2011-07-01

    In the present study we investigate computationally the steady-state motion of an elastic capsule along the centerline of a square microfluidic channel and compare it with that in a cylindrical tube. In particular, we consider a slightly over-inflated elastic capsule made of a strain-hardening membrane with comparable shearing and area-dilatation resistance. Under the conditions studied in this paper (i.e., small, moderate, and large capsules at low and moderate flow rates), the capsule motion in a square channel is similar to and thus governed by the same scaling laws with the capsule motion in a cylindrical tube, even though in the channel the cross section in the upstream portion of large capsules is nonaxisymmetric (i.e., square-like with rounded corners). When the hydrodynamic forces on the membrane increase, the capsule develops a pointed downstream edge and a flattened rear (possibly with a negative curvature) so that the restoring tension forces are increased as also happens with droplets. Membrane tensions increase significantly with the capsule size while the area near the downstream tip is the most probable to rupture when a capsule flows in a microchannel. Because the membrane tensions increase with the interfacial deformation, a suitable Landau-Levich-Derjaguin-Bretherton analysis reveals that the lubrication film thickness h for large capsules depends on both the capillary number Ca and the capsule size a; our computations determine the latter dependence to be (in dimensionless form) h ~ a(-2) for the large capsules studied in this work. For small and moderate capsule sizes a, the capsule velocity Ux and additional pressure drop ΔP+ are governed by the same scaling laws as for high-viscosity droplets. The velocity and additional pressure drop of large thick capsules also follow the dynamics of high-viscosity droplets, and are affected by the lubrication film thickness. The motion of our large thick capsules is characterized by a Ux-U ~ h ~ a(-2

  8. Capsule formation and asymbiotic seed germination in some hybrids of Phalaenopsis, influenced by pollination season and capsule maturity.

    PubMed

    Balilashaki, Khosro; Gantait, Saikat; Naderi, Roohangiz; Vahedi, Maryam

    2015-07-01

    We explored the influence of pollination season and maturity of capsule on post-pollination capsule formation and in vitro asymbiotic seed germination, respectively. Three Phalaenopsis orchid hybrids, namely, 'Athens', 'Moscow' and 'Lusaka' flowers were artificially self-pollinated during winter, spring, summer and fall seasons and the impact of the pollination seasons was evident during capsule formation. It was observed that winter was the most suitable season for pollination of all the three Phalanaeopsis hybrids resulting in 80-88 % capsule formation. During summer, the pollination success rate was 24-28 %, but resulted in successful capsule formation. Season of pollination further delimited the germination efficiency of seeds harvested from capsules of variable maturity levels. Invariably, seeds collected from winter-pollinated capsules performed best in germination compared to other seasons, for instance, 'Moscow' seeds took less than 14 days to germinate from capsules developed following winter-pollination. Regarding the influence of capsule maturity on seed germination, we observed that seeds derived from 5-month mature capsules, invariably took least time to germinate than that of the 3-month or 7-month in all three hybrids, e.g., for 'Moscow' it was 13.9 days with a maximum of 90.3 % germination.

  9. Recalcitrant polysaccharide degradation by novel oxidative biocatalysts.

    PubMed

    Dimarogona, Maria; Topakas, Evangelos; Christakopoulos, Paul

    2013-10-01

    The classical hydrolytic mechanism for the degradation of plant polysaccharides by saprophytic microorganisms has been reconsidered after the recent landmark discovery of a new class of oxidases termed lytic polysaccharide monooxygenases (LPMOs). LPMOs are of increased biotechnological interest due to their implication in lignocellulosic biomass decomposition for the production of biofuels and high-value chemicals. They act on recalcitrant polysaccharides by a combination of hydrolytic and oxidative function, generating oxidized and non-oxidized chain ends. They are copper-dependent and require molecular oxygen and an external electron donor for their proper function. In this review, we present the recent findings concerning the mechanism of action of these oxidative enzymes and identify issues and questions to be addressed in the future. PMID:23995228

  10. Influence of polysaccharides on wine protein aggregation.

    PubMed

    Jaeckels, Nadine; Meier, Miriam; Dietrich, Helmut; Will, Frank; Decker, Heinz; Fronk, Petra

    2016-06-01

    Polysaccharides are the major high-molecular weight components of wines. In contrast, proteins occur only in small amounts in wine, but contribute to haze formation. The detailed mechanism of aggregation of these proteins, especially in combination with other wine components, remains unclear. This study demonstrates the different aggregation behavior between a buffer and a model wine system by dynamic light scattering. Arabinogalactan-protein, for example, shows an increased aggregation in the model wine system, while in the buffer system a reducing effect is observed. Thus, we could show the importance to examine the behavior of wine additives under conditions close to reality, instead of simpler buffer systems. Additional experiments on melting points of wine proteins reveal that only some isoforms of thaumatin-like proteins and chitinases are involved in haze formation. We can confirm interactions between polysaccharides and proteins, but none of these polysaccharides is able to prevent haze in wine.

  11. Learning from microbial strategies for polysaccharide degradation.

    PubMed

    Hemsworth, Glyn R; Déjean, Guillaume; Davies, Gideon J; Brumer, Harry

    2016-02-01

    Complex carbohydrates are ubiquitous in all kingdoms of life. As major components of the plant cell wall they constitute both a rich renewable carbon source for biotechnological transformation into fuels, chemicals and materials, and also form an important energy source as part of a healthy human diet. In both contexts, there has been significant, sustained interest in understanding how microbes transform these substrates. Classical perspectives of microbial polysaccharide degradation are currently being augmented by recent advances in the discovery of lytic polysaccharide monooxygenases (LPMOs) and polysaccharide utilization loci (PULs). Fundamental discoveries in carbohydrate enzymology are both advancing biological understanding, as well as informing applications in industrial biomass conversion and modulation of the human gut microbiota to mediate health benefits.

  12. Role of shocks and mix caused by capsule defects

    NASA Astrophysics Data System (ADS)

    Bradley, P. A.; Cobble, J. A.; Tregillis, I. L.; Schmitt, M. J.; Obrey, K. D.; Glebov, V.; Batha, S. H.; Magelssen, G. R.; Fincke, J. R.; Hsu, S. C.; Krasheninnikova, N. S.; Murphy, T. J.; Wysocki, F. J.

    2012-09-01

    An Eulerian code with a turbulent mix model is used to model a set of plastic (CH) ablator capsules with and without equatorial grooves. The "perfect" capsule results were used to calibrate simulations of capsules with equatorial grooves of different depths that provided information on increasingly perturbed implosions. Simulations with a turbulence model were able to calculate the same yield over mix (YOM) ratio (experiment/mix simulation) of 0.2 to 0.3 for thin (8-μm thick) and thick shell (15-μm thick) capsules with no grooves and thin capsules with shallow grooves. When the capsules have deep grooves, the YOM ratio increases to greater than unity, probably because the deformed shocks focus too strongly on the symmetry axis in our two-dimensional simulations. This is supported by a comparison of simulated and experimental x-ray images.

  13. A Review of Locomotion Systems for Capsule Endoscopy.

    PubMed

    Liu, Lejie; Towfighian, Shahrzad; Hila, Amine

    2015-01-01

    Wireless capsule endoscopy for gastrointestinal (GI) tract is a modern technology that has the potential to replace conventional endoscopy techniques. Capsule endoscopy is a pill-shaped device embedded with a camera, a coin battery, and a data transfer. Without a locomotion system, this capsule endoscopy can only passively travel inside the GI tract via natural peristalsis, thus causing several disadvantages such as inability to control and stop, and risk of capsule retention. Therefore, a locomotion system needs to be added to optimize the current capsule endoscopy. This review summarizes the state-of-the-art locomotion methods along with the desired locomotion features such as size, speed, power, and temperature and compares the properties of different methods. In addition, properties and motility mechanisms of the GI tract are described. The main purpose of this review is to understand the features of GI tract and diverse locomotion methods in order to create a future capsule endoscopy compatible with GI tract properties. PMID:26292162

  14. Chemical mediation of egg capsule deposition by mud snails.

    PubMed

    Rittschof, Dan; Sawardecker, Prasad; Petry, Caroline

    2002-11-01

    Mud snails (Ilyanassa obsoleta = Nassarius obsoletus = Nassa obsoleta) deposit eggs in protective capsules on hard substrata in soft bottom environments. We studied sites of egg capsule deposition and snail movement responses to odors to determine if chemoreception plays a role in deposition site selection. From results of field surveys, laboratory experiments, and field experiments, we conclude that mud snails use chemoreception for capsule deposition. Attractive odors originate from mud snail and whelk egg capsules and from living bivalves. Evidence for attractive odors from conspecifics is equivocal. Capsules are deposited on living odor sources and nearby hard substrates. We hypothesize that deposition of capsules on living substrates increases the likelihood that embryos will survive by decreasing the chance of smothering of embryos by sediments. PMID:12523566

  15. 50 CFR 622.186 - Landing fish intact.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 12 2013-10-01 2013-10-01 false Landing fish intact. 622.186 Section 622...-Grouper Fishery of the South Atlantic Region § 622.186 Landing fish intact. (a) South Atlantic snapper... specified in paragraph (b) of this section. Such fish may be eviscerated, gilled, and scaled, but...

  16. 50 CFR 622.186 - Landing fish intact.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 12 2014-10-01 2014-10-01 false Landing fish intact. 622.186 Section 622...-Grouper Fishery of the South Atlantic Region § 622.186 Landing fish intact. (a) South Atlantic snapper... specified in paragraph (b) of this section. Such fish may be eviscerated, gilled, and scaled, but...

  17. 50 CFR 622.247 - Landing golden crab intact.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 12 2014-10-01 2014-10-01 false Landing golden crab intact. 622.247... ATLANTIC Golden Crab Fishery of the South Atlantic Region § 622.247 Landing golden crab intact. The operator of a vessel that fishes in the EEZ is responsible for ensuring that golden crab on that vessel...

  18. 50 CFR 622.247 - Landing golden crab intact.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 12 2013-10-01 2013-10-01 false Landing golden crab intact. 622.247... ATLANTIC Golden Crab Fishery of the South Atlantic Region § 622.247 Landing golden crab intact. The operator of a vessel that fishes in the EEZ is responsible for ensuring that golden crab on that vessel...

  19. 46 CFR 28.570 - Intact righting energy.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Intact righting energy. 28.570 Section 28.570 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY UNINSPECTED VESSELS REQUIREMENTS FOR COMMERCIAL FISHING INDUSTRY VESSELS Stability § 28.570 Intact righting energy. (a) Except as provided in paragraph (c) of...

  20. 46 CFR 28.570 - Intact righting energy.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Intact righting energy. 28.570 Section 28.570 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY UNINSPECTED VESSELS REQUIREMENTS FOR COMMERCIAL FISHING INDUSTRY VESSELS Stability § 28.570 Intact righting energy. (a) Except as provided in paragraph (c) of...

  1. 46 CFR 28.570 - Intact righting energy.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Intact righting energy. 28.570 Section 28.570 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY UNINSPECTED VESSELS REQUIREMENTS FOR COMMERCIAL FISHING INDUSTRY VESSELS Stability § 28.570 Intact righting energy. (a) Except as provided in paragraph (c) of...

  2. 46 CFR 28.570 - Intact righting energy.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Intact righting energy. 28.570 Section 28.570 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY UNINSPECTED VESSELS REQUIREMENTS FOR COMMERCIAL FISHING INDUSTRY VESSELS Stability § 28.570 Intact righting energy. (a) Except as provided in paragraph (c) of...

  3. 46 CFR 28.570 - Intact righting energy.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Intact righting energy. 28.570 Section 28.570 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY UNINSPECTED VESSELS REQUIREMENTS FOR COMMERCIAL FISHING INDUSTRY VESSELS Stability § 28.570 Intact righting energy. (a) Except as provided in paragraph (c) of...

  4. 46 CFR 170.165 - International Code on Intact Stability.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false International Code on Intact Stability. 170.165 Section 170.165 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY STABILITY REQUIREMENTS FOR ALL INSPECTED VESSELS Intact Stability Criteria § 170.165 International Code...

  5. 46 CFR 170.165 - International Code on Intact Stability.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false International Code on Intact Stability. 170.165 Section 170.165 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY STABILITY REQUIREMENTS FOR ALL INSPECTED VESSELS Intact Stability Criteria § 170.165 International Code...

  6. 46 CFR 174.020 - Alternate intact stability criterion.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Alternate intact stability criterion. 174.020 Section 174.020 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY... Alternate intact stability criterion. A barge need not comply with § 174.015 and subparts C and E of...

  7. 46 CFR 174.020 - Alternate intact stability criterion.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Alternate intact stability criterion. 174.020 Section 174.020 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY... Alternate intact stability criterion. A barge need not comply with § 174.015 and subparts C and E of...

  8. 46 CFR 172.165 - Intact stability calculations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Intact stability calculations. 172.165 Section 172.165 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES... Under Subchapter O of This Chapter § 172.165 Intact stability calculations. (a) Design calculations...

  9. 46 CFR 172.095 - Intact longitudinal stability.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Intact longitudinal stability. 172.095 Section 172.095 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES... Under Subchapter O of This Chapter § 172.095 Intact longitudinal stability. Each tank barge must...

  10. 46 CFR 174.020 - Alternate intact stability criterion.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Alternate intact stability criterion. 174.020 Section 174.020 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY... Alternate intact stability criterion. A barge need not comply with § 174.015 and subparts C and E of...

  11. 46 CFR 172.095 - Intact longitudinal stability.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Intact longitudinal stability. 172.095 Section 172.095 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES... Under Subchapter O of This Chapter § 172.095 Intact longitudinal stability. Each tank barge must...

  12. 46 CFR 170.165 - International Code on Intact Stability.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false International Code on Intact Stability. 170.165 Section 170.165 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY STABILITY REQUIREMENTS FOR ALL INSPECTED VESSELS Intact Stability Criteria § 170.165 International Code...

  13. 46 CFR 174.020 - Alternate intact stability criterion.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Alternate intact stability criterion. 174.020 Section 174.020 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY... Alternate intact stability criterion. A barge need not comply with § 174.015 and subparts C and E of...

  14. 46 CFR 172.165 - Intact stability calculations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Intact stability calculations. 172.165 Section 172.165 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES... Under Subchapter O of This Chapter § 172.165 Intact stability calculations. (a) Design calculations...

  15. 46 CFR 174.020 - Alternate intact stability criterion.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Alternate intact stability criterion. 174.020 Section 174.020 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY... Alternate intact stability criterion. A barge need not comply with § 174.015 and subparts C and E of...

  16. 46 CFR 172.095 - Intact longitudinal stability.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Intact longitudinal stability. 172.095 Section 172.095 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES... Under Subchapter O of This Chapter § 172.095 Intact longitudinal stability. Each tank barge must...

  17. 46 CFR 172.095 - Intact longitudinal stability.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Intact longitudinal stability. 172.095 Section 172.095 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES... Under Subchapter O of This Chapter § 172.095 Intact longitudinal stability. Each tank barge must...

  18. 46 CFR 170.165 - International Code on Intact Stability.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false International Code on Intact Stability. 170.165 Section 170.165 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY STABILITY REQUIREMENTS FOR ALL INSPECTED VESSELS Intact Stability Criteria § 170.165 International Code...

  19. 50 CFR 622.455 - Landing spiny lobster intact.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 12 2014-10-01 2014-10-01 false Landing spiny lobster intact. 622.455... ATLANTIC Spiny Lobster Fishery of Puerto Rico and the U.S. Virgin Islands § 622.455 Landing spiny lobster intact. (a) A Caribbean spiny lobster in or from the Caribbean EEZ must be maintained with head...

  20. 50 CFR 622.455 - Landing spiny lobster intact.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 12 2013-10-01 2013-10-01 false Landing spiny lobster intact. 622.455... ATLANTIC Spiny Lobster Fishery of Puerto Rico and the U.S. Virgin Islands § 622.455 Landing spiny lobster intact. (a) A Caribbean spiny lobster in or from the Caribbean EEZ must be maintained with head...

  1. 50 CFR 622.10 - Landing fish intact--general.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE CARIBBEAN, GULF OF MEXICO, AND SOUTH... landing fish intact that are broadly applicable to finfish in the Gulf EEZ and Caribbean EEZ, as specified... intact. (a) Finfish in or from the Gulf EEZ or Caribbean EEZ, except as specified in paragraphs (b)...

  2. 50 CFR 622.10 - Landing fish intact--general.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE CARIBBEAN, GULF OF MEXICO, AND SOUTH... landing fish intact that are broadly applicable to finfish in the Gulf EEZ and Caribbean EEZ, as specified... intact. (a) Finfish in or from the Gulf EEZ or Caribbean EEZ, except as specified in paragraphs (b)...

  3. 50 CFR 622.493 - Landing Caribbean queen conch intact.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 12 2013-10-01 2013-10-01 false Landing Caribbean queen conch intact. 622... ATLANTIC Queen Conch Resources of Puerto Rico and the U.S. Virgin Islands § 622.493 Landing Caribbean queen conch intact. (a) A Caribbean queen conch in or from the Caribbean EEZ must be maintained with meat...

  4. 50 CFR 622.493 - Landing Caribbean queen conch intact.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 12 2014-10-01 2014-10-01 false Landing Caribbean queen conch intact. 622... ATLANTIC Queen Conch Resources of Puerto Rico and the U.S. Virgin Islands § 622.493 Landing Caribbean queen conch intact. (a) A Caribbean queen conch in or from the Caribbean EEZ must be maintained with meat...

  5. 46 CFR 172.095 - Intact longitudinal stability.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Intact longitudinal stability. 172.095 Section 172.095... Under Subchapter O of This Chapter § 172.095 Intact longitudinal stability. Each tank barge must be shown by design calculations to have a longitudinal metacentric height (GM) in feet (meters) in...

  6. Evidence for Branching in Cryptococcal Capsular Polysaccharides and Consequences on its Biological Activity

    PubMed Central

    Cordero, Radames J.B.; Frases, Susana; Guimaräes, Allan J.; Rivera, Johanna; Casadevall, Arturo

    2011-01-01

    SUMMARY The encapsulated fungus Cryptococcus neoformans is a common cause of life-threatening disease in immunocompromised individuals. Its major virulence determinant is the polysaccharide (PS) capsule. An unsolved problem in cryptococcal biology is whether the PSs composing the capsule are linear or complex branched polymers, as well as the implications of this structural composition in pathogenesis. In this study we approached the problem by combining static and dynamic light scattering, viscosity analysis, and high-resolution microscopy and correlated the findings with biological properties. Analysis of the dependence of capsular PS molecular mass and the radius of gyration provided strong evidence against a simple linear PS configuration. Shape factors calculated from light scattering measurements in solution revealed values consistent with polymer branching. Furthermore, viscosity measurements provided complementary evidence for structural branching. Electron microscopy showed PS spherical-like structures similar to other branched PS. Finally, we show that the capacity of capsular PS to interfere in complement-mediated phagocytosis, inhibit nitric oxide production by macrophage-like cells, protect against reactive oxygen species, antibody reactivity and half-life in serum were influenced by the degree of branching, providing evidence for the notion that PS branching is an important parameter in determining the biological activity of C. neoformans PS. PMID:21208301

  7. Evidence for branching in cryptococcal capsular polysaccharides and consequences on its biological activity.

    PubMed

    Cordero, Radames J B; Frases, Susana; Guimaräes, Allan J; Rivera, Johanna; Casadevall, Arturo

    2011-02-01

    The encapsulated fungus Cryptococcus neoformans is a common cause of life-threatening disease in immunocompromised individuals. Its major virulence determinant is the polysaccharide (PS) capsule. An unsolved problem in cryptococcal biology is whether the PSs composing the capsule are linear or complex branched polymers, as well as the implications of this structural composition in pathogenesis. In this study we approached the problem by combining static and dynamic light scattering, viscosity analysis, and high-resolution microscopy and correlated the findings with biological properties. Analysis of the dependence of capsular PS molecular mass and the radius of gyration provided strong evidence against a simple linear PS configuration. Shape factors calculated from light scattering measurements in solution revealed values consistent with polymer branching. Furthermore, viscosity measurements provided complementary evidence for structural branching. Electron microscopy showed PS spherical-like structures similar to other branched PS. Finally, we show that the capacity of capsular PS to interfere in complement-mediated phagocytosis, inhibit nitric oxide production by macrophage-like cells, protect against reactive oxygen species, antibody reactivity and half-life in serum were influenced by the degree of branching, providing evidence for the notion that PS branching is an important parameter in determining the biological activity of C. neoformans PS.

  8. Ultrasonic technique for inspection of GPHS capsule girth weld integrity

    SciTech Connect

    Placr, Arnost

    1993-05-01

    An innovative nondestructive examination (NDE) technique for the inspection of integrity of General Purpose Heat Source (GPHS) capsule girth welds (Figure 1) was developed employing a Lamb (plate) wave as the mode of the sound propagation. Reliability of the Lamb wave technique was tested on GPHS capsules using plutonium pallet simulators. All ten capsules, which were previously rejected, passed ultrasonic (UT) inspection using the Lamb wave technique.

  9. [Effect of eel oil capsule on mice memory].

    PubMed

    Zhang, X; Zhang, Y; Xu, D; Xu, S; Huang, X

    1998-06-01

    Step-down test, step-through test and water maze in mice were used to observe the effect of eel oil capsule on mice memory. The results indicated that during the administration period (30 days), the eel oil capsule treating groups with dosages of 0.129, 0.387, and 1.161 g/kg obviously improved the learning and memory abilities. Compared with the control test, the eel oil capsule promoted the memory and smart.

  10. A unique capsular polysaccharide structure from the psychrophilic marine bacterium Colwellia psychrerythraea 34H that mimics antifreeze (glyco)proteins.

    PubMed

    Carillo, Sara; Casillo, Angela; Pieretti, Giuseppina; Parrilli, Ermenegilda; Sannino, Filomena; Bayer-Giraldi, Maddalena; Cosconati, Sandro; Novellino, Ettore; Ewert, Marcela; Deming, Jody W; Lanzetta, Rosa; Marino, Gennaro; Parrilli, Michelangelo; Randazzo, Antonio; Tutino, Maria L; Corsaro, M Michela

    2015-01-14

    The low temperatures of polar regions and high-altitude environments, especially icy habitats, present challenges for many microorganisms. Their ability to live under subfreezing conditions implies the production of compounds conferring cryotolerance. Colwellia psychrerythraea 34H, a γ-proteobacterium isolated from subzero Arctic marine sediments, provides a model for the study of life in cold environments. We report here the identification and detailed molecular primary and secondary structures of capsular polysaccharide from C. psychrerythraea 34H cells. The polymer was isolated in the water layer when cells were extracted by phenol/water and characterized by one- and two-dimensional NMR spectroscopy together with chemical analysis. Molecular mechanics and dynamics calculations were also performed. The polysaccharide consists of a tetrasaccharidic repeating unit containing two amino sugars and two uronic acids bearing threonine as substituent. The structural features of this unique polysaccharide resemble those present in antifreeze proteins and glycoproteins. These results suggest a possible correlation between the capsule structure and the ability of C. psychrerythraea to colonize subfreezing marine environments.

  11. Small intestinal model for electrically propelled capsule endoscopy

    PubMed Central

    2011-01-01

    The aim of this research is to propose a small intestine model for electrically propelled capsule endoscopy. The electrical stimulus can cause contraction of the small intestine and propel the capsule along the lumen. The proposed model considered the drag and friction from the small intestine using a thin walled model and Stokes' drag equation. Further, contraction force from the small intestine was modeled by using regression analysis. From the proposed model, the acceleration and velocity of various exterior shapes of capsule were calculated, and two exterior shapes of capsules were proposed based on the internal volume of the capsules. The proposed capsules were fabricated and animal experiments were conducted. One of the proposed capsules showed an average (SD) velocity in forward direction of 2.91 ± 0.99 mm/s and 2.23 ± 0.78 mm/s in the backward direction, which was 5.2 times faster than that obtained in previous research. The proposed model can predict locomotion of the capsule based on various exterior shapes of the capsule. PMID:22177218

  12. ADHESIVE CAPSULITIS: USE THE EVIDENCE TO INTEGRATE YOUR INTERVENTIONS

    PubMed Central

    Labbe, Andre

    2010-01-01

    Frozen shoulder syndrome, clinically known as adhesive capsulitis, is a painful and debilitating condition affecting up to 5% of the population. Adhesive capsulitis is considered fibrosis of the glenohumeral joint capsule with a chronic inflammatory response. Patients experience pain, limited range of motion, and disability generally lasting anywhere from 1 to 24 months. The purpose of this clinical suggestion is to review the pathophysiolgy of adhesive capsulitis and discuss physical therapy interventions which are supported by evidence, thereby enhancing evidence-based practice. PMID:21655385

  13. Wireless capsule endoscopy: indications, limitations, and future challenges.

    PubMed

    El-Matary, Wael

    2008-01-01

    Wireless capsule endoscopy is one of the recent inventions that has made an impact in the diagnostic work-up of gastrointestinal diseases, mainly in small intestinal pathology, the part of the gut that cannot be totally visualized by upper and lower gastrointestinal endoscopy. Since the first report documenting the use of capsule endoscopy, many adult clinical trials have taken place. Although the Food and Drug Administration approved the use of the capsule in children (ages 10-18 years) in October 2003, few small clinical trials exploring the diagnostic yield of capsule endoscopy in pediatric populations have been published. PMID:18162827

  14. Transient dynamics of an elastic capsule in a microfluidic constriction

    PubMed Central

    Park, Sun-Young; Dimitrakopoulos, P.

    2013-01-01

    In this paper we investigate computationally the transient dynamics of an elastic capsule flowing in a square microchannel with a rectangular constriction, and compare it with that of a droplet. The confinement and expansion dynamics of the fluid flow results in a rich deformation behavior for the capsule, from an elongated shape at the constriction entrance, to a flattened parachute shape at its exit. Larger capsules are shown to take more time to pass the constriction and cause higher additional pressure difference, owing to higher flow blocking. Our work highlights the effects of two different mechanisms for non-tank-treading transient capsule dynamics. The capsule deformation results from the combined effects of the surrounding and inner fluids’ normal stresses on the soft particle’s interface, and thus when the capsule viscosity increases, its transient deformation decreases, as for droplets. However, the capsule deformation is not able to create a strong enough inner circulation (owing to restrictions imposed by the material membrane), and thus the viscosity ratio does not affect much the capsule velocity and the additional pressure difference. In addition, the weak inner circulation results in a positive additional pressure difference ΔP+ even for low-viscosity capsules, in direct contrast to low-viscosity droplets which create a negative ΔP+. Our findings suggest that the high cytoplasmatic viscosity, owing to the protein hemoglobin required for oxygen transport, does not affect adversely the motion of non-tank-trading erythrocytes in vascular capillaries. PMID:24223621

  15. Procedures For Making Precision CH Bumps On Capsules

    SciTech Connect

    Letts, S; Fearon, E; Buckley, S; Klingmann, J; Cook, B

    2004-11-10

    Recently we were asked to produce target capsules with bumps on the surface. The bumps were to test the effects of fill tubes in future targets. The bumps desired were to be Gaussian in shape and from 60 to 40 {micro}m in diameter and from 1 to 6 {micro}m high. The capsules had a nominal diameter of 500 {micro}m. The approach we used was to align a precision aperture to the capsule and coat through the aperture onto the capsule surface using plasma polymer coating. The bumps were characterized using optical microscopy, Wyko interferometry, and AFM sphere mapping.

  16. Method of forming capsules containing a precise amount of material

    DOEpatents

    Grossman, M.W.; George, W.A.; Maya, J.

    1986-06-24

    A method of forming a sealed capsule containing a submilligram quantity of mercury or the like, the capsule being constructed from a hollow glass tube, by placing a globule or droplet of the mercury in the tube. The tube is then evacuated and sealed and is subsequently heated so as to vaporize the mercury and fill the tube therewith. The tube is then separated into separate sealed capsules by heating spaced locations along the tube with a coiled heating wire means to cause collapse spaced locations there along and thus enable separation of the tube into said capsules. 7 figs.

  17. Method of forming capsules containing a precise amount of material

    DOEpatents

    Grossman, Mark W.; George, William A.; Maya, Jakob

    1986-01-01

    A method of forming a sealed capsule containing a submilligram quantity of mercury or the like, the capsule being constructed from a hollow glass tube, by placing a globule or droplet of the mercury in the tube. The tube is then evacuated and sealed and is subsequently heated so as to vaporize the mercury and fill the tube therewith. The tube is then separated into separate sealed capsules by heating spaced locations along the tube with a coiled heating wire means to cause collapse spaced locations therealong and thus enable separation of the tube into said capsules.

  18. Tests for intact and collapsed magnetofossil chains

    NASA Astrophysics Data System (ADS)

    Egli, R.

    2012-04-01

    first time. These results match measurements obtained previously on magnetosome-rich sediments in smallest details, showing that the identification of distinct intact and collapsed chain structures is possible. On the other hand, these results show that caution should be used when interpreting sediment hysteresis properties as mixtures of single domain (SD), multidomain (MD), and superparamagnetic (SP) particles; because some collapsed chain structures closely mimic SD-MD-SP mixing trends in a Day plot, although being made only of SD particles.

  19. Abrogation of neuraminidase reduces biofilm formation, capsule biosynthesis, and virulence of Porphyromonas gingivalis.

    PubMed

    Li, Chen; Kurniyati; Hu, Bo; Bian, Jiang; Sun, Jianlan; Zhang, Weiyan; Liu, Jun; Pan, Yaping; Li, Chunhao

    2012-01-01

    The oral bacterium Porphyromonas gingivalis is a key etiological agent of human periodontitis, a prevalent chronic disease that affects up to 80% of the adult population worldwide. P. gingivalis exhibits neuraminidase activity. However, the enzyme responsible for this activity, its biochemical features, and its role in the physiology and virulence of P. gingivalis remain elusive. In this report, we found that P. gingivalis encodes a neuraminidase, PG0352 (SiaPg). Transcriptional analysis showed that PG0352 is monocistronic and is regulated by a sigma70-like promoter. Biochemical analyses demonstrated that SiaPg is an exo-α-neuraminidase that cleaves glycosidic-linked sialic acids. Cryoelectron microscopy and tomography analyses revealed that the PG0352 deletion mutant (ΔPG352) failed to produce an intact capsule layer. Compared to the wild type, in vitro studies showed that ΔPG352 formed less biofilm and was less resistant to killing by the host complement. In vivo studies showed that while the wild type caused a spreading type of infection that affected multiple organs and all infected mice were killed, ΔPG352 only caused localized infection and all animals survived. Taken together, these results demonstrate that SiaPg is an important virulence factor that contributes to the biofilm formation, capsule biosynthesis, and pathogenicity of P. gingivalis, and it can potentially serve as a new target for developing therapeutic agents against P. gingivalis infection.

  20. [Evaluation of stability of temozolomide in solutions after opening the capsule].

    PubMed

    Kodawara, Takaaki; Mizuno, Tomoyuki; Taue, Hiromi; Hashida, Tohru; Yano, Ikuko; Katsura, Toshiya; Inui, Ken-Ichi

    2009-03-01

    We evaluated the stability of temozolomide, an alkylating agent, in solutions after opening the capsule. First, we established an analytical method for determination of temozolomide concentration by HPLC. The calibration curve for temozolomide was linear between 0.5-20 microg/ml (r=0.999). We then evaluated the stability of temozolomide in each buffer solution (pH 2-9) for 30 min. Temozolomide was decomposed pH-dependently between pH 7 and 9, and completely decomposed at pH 9. Temozolomide in several drinking water samples and beverages was decomposed according to their pH values. We also examined the time-dependent degradation of temozolomide in different pH solutions. Temozolomide started to decompose at 5 min in alkaline and neutral solutions, whereas 90% of temozolomide remained intact in acidic solution at 60 min. These results indicate that the stability of temozolomide after opening the capsule is affected by pH of solvents, and temozolomide is almost stable in acidic solutions. PMID:19252393

  1. Abrogation of Neuraminidase Reduces Biofilm Formation, Capsule Biosynthesis, and Virulence of Porphyromonas gingivalis

    PubMed Central

    Li, Chen; Kurniyati; Hu, Bo; Bian, Jiang; Sun, Jianlan; Zhang, Weiyan; Liu, Jun; Pan, Yaping

    2012-01-01

    The oral bacterium Porphyromonas gingivalis is a key etiological agent of human periodontitis, a prevalent chronic disease that affects up to 80% of the adult population worldwide. P. gingivalis exhibits neuraminidase activity. However, the enzyme responsible for this activity, its biochemical features, and its role in the physiology and virulence of P. gingivalis remain elusive. In this report, we found that P. gingivalis encodes a neuraminidase, PG0352 (SiaPg). Transcriptional analysis showed that PG0352 is monocistronic and is regulated by a sigma70-like promoter. Biochemical analyses demonstrated that SiaPg is an exo-α-neuraminidase that cleaves glycosidic-linked sialic acids. Cryoelectron microscopy and tomography analyses revealed that the PG0352 deletion mutant (ΔPG352) failed to produce an intact capsule layer. Compared to the wild type, in vitro studies showed that ΔPG352 formed less biofilm and was less resistant to killing by the host complement. In vivo studies showed that while the wild type caused a spreading type of infection that affected multiple organs and all infected mice were killed, ΔPG352 only caused localized infection and all animals survived. Taken together, these results demonstrate that SiaPg is an important virulence factor that contributes to the biofilm formation, capsule biosynthesis, and pathogenicity of P. gingivalis, and it can potentially serve as a new target for developing therapeutic agents against P. gingivalis infection. PMID:22025518

  2. Cholesterol-mediated anchoring of enzyme-loaded liposomes within disulfide-stabilized polymer carrier capsules.

    PubMed

    Chandrawati, Rona; Städler, Brigitte; Postma, Almar; Connal, Luke A; Chong, Siow-Feng; Zelikin, Alexander N; Caruso, Frank

    2009-10-01

    Polymer capsules containing multiple liposomes, termed capsosomes, are a promising new concept toward the design of artificial cells. Herein, we report on the fundamental aspects underpinning the assembly of capsosomes. A stable and high loading of intact liposomal cargo into a polymer film was achieved by non-covalently sandwiching the liposomes between a tailor-made cholesterol-modified poly(L-lysine) (PLL(c)) precursor layer and a poly(methacrylic acid)-co-(cholesteryl methacrylate) (PMA(c)) capping layer. The film assembly, optimized on planar surfaces, was successfully transferred onto colloidal substrates, and a polymer membrane was subsequently assembled by the alternating adsorption of poly(N-vinyl pyrrolidone) (PVP) and thiol-modified poly(methacrylic acid) (PMA(SH)) onto the pre-adsorbed layer of liposomes. Upon removal of the silica template, stable capsosomes encapsulating the enzyme luciferase or beta-lactamase within their liposomal sub-compartments were obtained at both assembly (pH 4) and physiological conditions (pH 7.4). Excellent retention of the liposomes and the enzymatic cargo within the polymer carrier capsules was observed for up to 14 days. These engineered capsosomes are particularly attractive as autonomous microreactors, which can be utilized to repetitively add smaller reactants to cause successive distinct reactions within the capsosomes and simultaneously release the products to the surrounding environment, bringing these systems one step closer toward constructing artificial cells.

  3. Video capsule endoscopy: is bowel preparation necessary?

    PubMed

    Catalano, Carmine; Companioni, Rafael Antonio Ching; Khankhanian, Pouya; Vyas, Neil; Patel, Ishan; Bansal, Raghav; Walfish, Aaron

    2016-08-01

    There is no standardized protocol for bowel preparation prior to video capsule endoscopy, although one is strongly recommended. The purpose of our study was to see if there was a statistical significance between small bowel mucosal visualization rates for those who received bowel preparation and those who did not. We retrospectively analyzed all patients who had a video capsule endoscopy from August 2014 to January 2016 at a tertiary care center. All patients fasted prior to the procedure. Bowel preparation when used consisted of polyethylene glycol. A long fast consisted of 12 or more hours. The grading system used to assess the small bowel was adapted from a previously validated system from Esaki et al Statistical analyses were performed using Fisher's exact test or Welch's 2-sample t-test and statistical significance was present if the p value was ≤0.05. 76 patients were carried forward for analysis. Small bowel mucosal visualization rates were similar between those who received bowel preparation and those who did not (92.5% vs 88.9%, p=0.44). Small bowel mucosal visualization rates were significantly better in those patients who had a long fast compared with those who had a short fast (97.7% vs 81.3%, p=0.019). Our study demonstrates that the addition of bowel preparation prior to video capsule endoscopy does not significantly improve small bowel mucosal visualization rates and, in addition, there is a statistically significant relationship between increased fasting time and improved small bowel mucosal visualization. A prolonged fast without bowel preparation might be satisfactory for an adequate small bowel visualization but further randomized, prospective studies are necessary to confirm these findings. PMID:27271277

  4. Effect of enzyme-aided cell wall disintegration on protein extractability from intact and dehulled rapeseed (Brassica rapa L. and Brassica napus L.) press cakes.

    PubMed

    Rommi, Katariina; Hakala, Terhi K; Holopainen, Ulla; Nordlund, Emilia; Poutanen, Kaisa; Lantto, Raija

    2014-08-13

    Cell-wall- and pectin-degrading enzyme preparations were used to enhance extractability of proteins from rapeseed press cake. Rapeseed press cakes from cold pressing of intact Brassica rapa and partially dehulled Brassica napus seeds, containing 36-40% protein and 35% carbohydrates, were treated with pectinolytic (Pectinex Ultra SP-L), xylanolytic (Depol 740L), and cellulolytic (Celluclast 1.5L) enzyme preparations. Pectinex caused effective disintegration of embryonic cell walls through hydrolysis of pectic polysaccharides and glucans and increased protein extraction by up to 1.7-fold in comparison to treatment without enzyme addition. Accordingly, 56% and 74% of the total protein in the intact and dehulled press cakes was extracted. Light microscopy of the press cakes suggested the presence of pectins colocalized with proteins inside the embryo cells. Hydrolysis of these intracellular pectins and deconstruction of embryonic cell walls during Pectinex treatment were concluded to relate with enhanced protein release.

  5. Dopant Distribution in NIF Beryllium Ablator Capsules

    NASA Astrophysics Data System (ADS)

    Huang, H.; Xu, H. W.; Youngblood, K. P.; Wall, D. R.; Stephens, R. B.; Moreno, K. A.; Nikroo, A.; Salmonson, J. D.; Haan, S. W.; Wu, K. J.; Wang, Y. M.; Hamza, A. V.

    2012-10-01

    Good implosion performance requires capsule ablator material with spherically uniform x-ray opacity, which is controlled by one of several dopants (Cu, Si, Al, etc.) in the Be shell. During production, the dopant concentration is radially stepped. However, the various Be-dopant interactions result in vastly different dopant distribution patterns, some quite inhomogeneous. We have characterized these structures and established the phenomenological basis and the magnitudes of the inhomogeneity both in spatial length scales and in atomic percent. We will discuss the case of inhomogeneous Cu diffusion in detail, followed by discussions of other dopants and the estimate of the impact of these structures on target implosion.

  6. Postirradiation examination of capsule GF-4. [HTGR

    SciTech Connect

    Kovacs, W.J.; Sedlak, B.J.

    1980-10-01

    The GF-4 capsule test was irradiated in the SILOE reactor at Grenoble, France between April 8, 1975 and July 26, 1976. High-enriched uranium (HEU) UC/sub 2/ and weak acid resin (WAR) UC/sub x/O/sub y/ fissile and ThO/sub 2/ fertile particles were tested. Postirradiation examination of cured-in-place fuel rods showed no fuel rod/graphite element interaction. In addition, all rods exhibited adequate structural integrity. Irradiation-induced dimensional changes for rods containing all TRISO-coated fuel were consistent with model predictions; however, rods containing BISO-coated fuel exhibited greater volumetric contractions than predicted.

  7. Polysaccharide-based strategies for heart tissue engineering.

    PubMed

    Silva, Amanda K A; Juenet, Maya; Meddahi-Pellé, Anne; Letourneur, Didier

    2015-02-13

    Polysaccharides are abundant biomolecules in nature presenting important roles in a wide variety of living systems processes. Considering the structural and biological functions of polysaccharides, their properties have raised interest for tissue engineering. Herein, we described the latest advances in cardiac tissue engineering mediated by polysaccharides. We reviewed the data already obtained in vitro and in vivo in this field with several types of polysaccharides. Cardiac injection, intramyocardial in situ polymerization strategies, and scaffold-based approaches involving polysaccharides for heart tissue engineering are thus discussed.

  8. Shapes of sedimenting soft elastic capsules in a viscous fluid.

    PubMed

    Boltz, Horst-Holger; Kierfeld, Jan

    2015-09-01

    Soft elastic capsules which are driven through a viscous fluid undergo shape deformation coupled to their motion. We introduce an iterative solution scheme which couples hydrodynamic boundary integral methods and elastic shape equations to find the stationary axisymmetric shape and the velocity of an elastic capsule moving in a viscous fluid at low Reynolds numbers. We use this approach to systematically study dynamical shape transitions of capsules with Hookean stretching and bending energies and spherical rest shape sedimenting under the influence of gravity or centrifugal forces. We find three types of possible axisymmetric stationary shapes for sedimenting capsules with fixed volume: a pseudospherical state, a pear-shaped state, and buckled shapes. Capsule shapes are controlled by two dimensionless parameters, the Föppl-von-Kármán number characterizing the elastic properties and a Bond number characterizing the driving force. For increasing gravitational force the spherical shape transforms into a pear shape. For very large bending rigidity (very small Föppl-von-Kármán number) this transition is discontinuous with shape hysteresis. The corresponding transition line terminates, however, in a critical point, such that the discontinuous transition is not present at typical Föppl-von-Kármán numbers of synthetic capsules. In an additional bifurcation, buckled shapes occur upon increasing the gravitational force. This type of instability should be observable for generic synthetic capsules. All shape bifurcations can be resolved in the force-velocity relation of sedimenting capsules, where up to three capsule shapes with different velocities can occur for the same driving force. All three types of possible axisymmetric stationary shapes are stable with respect to rotation during sedimentation. Additionally, we study capsules pushed or pulled by a point force, where we always find capsule shapes to transform smoothly without bifurcations. PMID:26465552

  9. Shapes of sedimenting soft elastic capsules in a viscous fluid

    NASA Astrophysics Data System (ADS)

    Boltz, Horst-Holger; Kierfeld, Jan

    2015-09-01

    Soft elastic capsules which are driven through a viscous fluid undergo shape deformation coupled to their motion. We introduce an iterative solution scheme which couples hydrodynamic boundary integral methods and elastic shape equations to find the stationary axisymmetric shape and the velocity of an elastic capsule moving in a viscous fluid at low Reynolds numbers. We use this approach to systematically study dynamical shape transitions of capsules with Hookean stretching and bending energies and spherical rest shape sedimenting under the influence of gravity or centrifugal forces. We find three types of possible axisymmetric stationary shapes for sedimenting capsules with fixed volume: a pseudospherical state, a pear-shaped state, and buckled shapes. Capsule shapes are controlled by two dimensionless parameters, the Föppl-von-Kármán number characterizing the elastic properties and a Bond number characterizing the driving force. For increasing gravitational force the spherical shape transforms into a pear shape. For very large bending rigidity (very small Föppl-von-Kármán number) this transition is discontinuous with shape hysteresis. The corresponding transition line terminates, however, in a critical point, such that the discontinuous transition is not present at typical Föppl-von-Kármán numbers of synthetic capsules. In an additional bifurcation, buckled shapes occur upon increasing the gravitational force. This type of instability should be observable for generic synthetic capsules. All shape bifurcations can be resolved in the force-velocity relation of sedimenting capsules, where up to three capsule shapes with different velocities can occur for the same driving force. All three types of possible axisymmetric stationary shapes are stable with respect to rotation during sedimentation. Additionally, we study capsules pushed or pulled by a point force, where we always find capsule shapes to transform smoothly without bifurcations.

  10. Shapes of sedimenting soft elastic capsules in a viscous fluid.

    PubMed

    Boltz, Horst-Holger; Kierfeld, Jan

    2015-09-01

    Soft elastic capsules which are driven through a viscous fluid undergo shape deformation coupled to their motion. We introduce an iterative solution scheme which couples hydrodynamic boundary integral methods and elastic shape equations to find the stationary axisymmetric shape and the velocity of an elastic capsule moving in a viscous fluid at low Reynolds numbers. We use this approach to systematically study dynamical shape transitions of capsules with Hookean stretching and bending energies and spherical rest shape sedimenting under the influence of gravity or centrifugal forces. We find three types of possible axisymmetric stationary shapes for sedimenting capsules with fixed volume: a pseudospherical state, a pear-shaped state, and buckled shapes. Capsule shapes are controlled by two dimensionless parameters, the Föppl-von-Kármán number characterizing the elastic properties and a Bond number characterizing the driving force. For increasing gravitational force the spherical shape transforms into a pear shape. For very large bending rigidity (very small Föppl-von-Kármán number) this transition is discontinuous with shape hysteresis. The corresponding transition line terminates, however, in a critical point, such that the discontinuous transition is not present at typical Föppl-von-Kármán numbers of synthetic capsules. In an additional bifurcation, buckled shapes occur upon increasing the gravitational force. This type of instability should be observable for generic synthetic capsules. All shape bifurcations can be resolved in the force-velocity relation of sedimenting capsules, where up to three capsule shapes with different velocities can occur for the same driving force. All three types of possible axisymmetric stationary shapes are stable with respect to rotation during sedimentation. Additionally, we study capsules pushed or pulled by a point force, where we always find capsule shapes to transform smoothly without bifurcations.

  11. Anticorrosive Microbial Polysaccharides: Structure-Function Relationships

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Water-soluble microbial polysaccharides are often implicated in biofilm formation and are believed to mediate cell-cell aggregation and adhesion to surfaces. Generally, biofilm formation is considered harmful or undesirable, as it leads to increased drag, plugging of pores, dimished heat transfer, ...

  12. Antitumor activity of methylan polysaccharide derivatives.

    PubMed

    Ramachandran, Priyadharshini; Jeya, Marimuthu; Moon, Hee-Jung; Lee, Kyoung-Mi; Kim, In-Won; Kim, Jung-Hoe; Lee, Jung-Kul

    2010-07-01

    Methylan polysaccharide derivatives were prepared by dialkylaminoalkylation and reductive amination followed by quaternization. Their antitumor activity was investigated and a relationship between structure and activity is suggested. For quaternized DEAE-methylan at only 75 mug ml(-1), tumor cell proliferation was suppressed by 58-84% in three cell lines tested in the order Colo < Hela < HepG2. PMID:20349111

  13. Fucoidans — sulfated polysaccharides of brown algae

    NASA Astrophysics Data System (ADS)

    Usov, Anatolii I.; Bilan, M. I.

    2009-08-01

    The methods of isolation of fucoidans and determination of their chemical structures are reviewed. The fucoidans represent sulfated polysaccharides of brown algae, the composition of which varies from simple fucan sulfates to complex heteropolysaccharides. The currently known structures of such biopolymers are presented. A variety of the biological activities of fucoidans is briefly summarised.

  14. Plant-Polysaccharide-Degrading Enzymes from Basidiomycetes

    PubMed Central

    Rytioja, Johanna; Hildén, Kristiina; Yuzon, Jennifer; Hatakka, Annele; de Vries, Ronald P.

    2014-01-01

    SUMMARY Basidiomycete fungi subsist on various types of plant material in diverse environments, from living and dead trees and forest litter to crops and grasses and to decaying plant matter in soils. Due to the variation in their natural carbon sources, basidiomycetes have highly varied plant-polysaccharide-degrading capabilities. This topic is not as well studied for basidiomycetes as for ascomycete fungi, which are the main sources of knowledge on fungal plant polysaccharide degradation. Research on plant-biomass-decaying fungi has focused on isolating enzymes for current and future applications, such as for the production of fuels, the food industry, and waste treatment. More recently, genomic studies of basidiomycete fungi have provided a profound view of the plant-biomass-degrading potential of wood-rotting, litter-decomposing, plant-pathogenic, and ectomycorrhizal (ECM) basidiomycetes. This review summarizes the current knowledge on plant polysaccharide depolymerization by basidiomycete species from diverse habitats. In addition, these data are compared to those for the most broadly studied ascomycete genus, Aspergillus, to provide insight into specific features of basidiomycetes with respect to plant polysaccharide degradation. PMID:25428937

  15. Antitumor activity of methylan polysaccharide derivatives.

    PubMed

    Ramachandran, Priyadharshini; Jeya, Marimuthu; Moon, Hee-Jung; Lee, Kyoung-Mi; Kim, In-Won; Kim, Jung-Hoe; Lee, Jung-Kul

    2010-07-01

    Methylan polysaccharide derivatives were prepared by dialkylaminoalkylation and reductive amination followed by quaternization. Their antitumor activity was investigated and a relationship between structure and activity is suggested. For quaternized DEAE-methylan at only 75 mug ml(-1), tumor cell proliferation was suppressed by 58-84% in three cell lines tested in the order Colo < Hela < HepG2.

  16. Aldehyde-containing urea-absorbing polysaccharides

    NASA Technical Reports Server (NTRS)

    Mueller, W. A.; Hsu, G. C.; Marsh, H. E., Jr. (Inventor)

    1977-01-01

    A novel aldehyde containing polymer (ACP) is prepared by reaction of a polysaccharide with periodate to introduce aldehyde groups onto the C2 - C3 carbon atoms. By introduction of ether and ester groups onto the pendant primary hydroxyl solubility characteristics are modified. The ACP is utilized to absorb nitrogen bases such as urea in vitro or in vivo.

  17. Reflectance Spectra Comparison of Orbital Debris, Intact Spacecraft, and Intact Rocket Bodies in the GEO Regime

    NASA Technical Reports Server (NTRS)

    Barker, Ed; Abercromby, Kira J.; Abell, Paul

    2009-01-01

    A key objective of NASA s Orbital Debris program office at Johnson Space Center (JSC) is to characterize the debris environment by way of assessing the physical properties (type, mass, density, and size) of objects in orbit. Knowledge of the geosynchronous orbit (GEO) debris environment in particular can be used to determine the hazard probability at specific GEO altitudes and aid predictions of the future environment. To calculate an optical size from an intensity measurement of an object in the GEO regime, a 0.175 albedo is assumed currently. However, identification of specific material type or types could improve albedo accuracy and yield a more accurate size estimate for the debris piece. Using spectroscopy, it is possible to determine the surface materials of space objects. The study described herein used the NASA Infrared Telescope Facility (IRTF) to record spectral data in the 0.6 to 2.5 micron regime on eight catalogued space objects. For comparison, all of the objects observed were in GEO or near-GEO. The eight objects consisted of two intact spacecraft, three rocket bodies, and three catalogued debris pieces. Two of the debris pieces stemmed from Titan 3C transtage breakup and the third is from COSMOS 2054. The reflectance spectra of the Titan 3C pieces share similar slopes (increasing with wavelength) and lack any strong absorption features. The COSMOS debris spectra is flat and has no absorption features. In contrast, the intact spacecraft show classic absorption features due to solar panels with a strong band gap feature near 1 micron. The two spacecraft are spin-stabilized objects and therefore have solar panels surrounding the outer surface. Two of the three rocket bodies are inertial upper stage (IUS) rocket bodies and have similar looking spectra. The slopes flatten out near 1.5 microns with absorption features in the near-infrared that are similar to that of white paint. The third rocket body has a similar flattening of slope but with fewer

  18. Reflectance Spectra Comparison of Orbital Debris, Intact Spacecraft, and Intact Rocket Bodies in the GEO Regime

    NASA Astrophysics Data System (ADS)

    Albercromby, Kira J.; Abell, Paul; Barker, Ed

    2009-03-01

    A key objective of NASA's Orbital Debris program office at Johnson Space Center (JSC) is to characterize the debris environment by way of assessing the physical properties (type, mass, density, and size) of objects in orbit. Knowledge of the geosynchronous orbit (GEO) debris environment in particular can be used to determine the hazard probability at specific GEO altitudes and aid predictions of the future environment. To calculate an optical size from an intensity measurement of an object in the GEO regime, a 0.175 albedo is assumed currently. However, identification of specific material type or types could improve albedo accuracy and yield a more accurate size estimate for the debris piece. Using spectroscopy, it is possible to determine the surface materials of space objects. The study described herein used the NASA Infrared Telescope Facility (IRTF) to record spectral data in the ~ 0.65 to 2.5 micron regime on eight catalogued space objects. For comparison, all of the objects observed were in GEO or near-GEO. The eight objects consisted of two intact spacecraft, three rocket bodies, and three catalogued debris pieces. Two of the debris pieces stemmed from Titan 3C transtage breakup and the third is from COSMOS 2054. The reflectance spectra of the Titan 3C pieces share similar slopes (increasing with wavelength) and lack any strong absorption features. The COSMOS debris spectrum has a slight slope and has no absorption features. In contrast, the intact spacecraft show classic absorption features due to solar cells with a strong band gap feature near 1 micron. The two spacecraft were spin-stabilized objects and therefore have solar panels surrounding the outer surface. Two of the three rocket bodies are inertial upper stage (IUS) rocket bodies and have similar looking spectra. The slopes flatten out near 1.5 microns with absorption features in the near-infrared that are similar to that of white paint. The third rocket body has a similar flattening of slope but

  19. Purification and characterization of Staphylococcus aureus type 8 capsular polysaccharide.

    PubMed Central

    Fournier, J M; Vann, W F; Karakawa, W W

    1984-01-01

    Clinical isolates of Staphylococcus aureus have been previously classified into eight types on the basis of their capsular polysaccharide. The high prevalence of the type 8 capsular polysaccharide among bacteremic isolates suggests the importance of this capsular antigen in staphylococcal disease. The capsular polysaccharide was purified from extracts of three clinical isolates of S. aureus type 8 of different geographic and temperal origin by ion-exchange chromatography and gel filtration. Gas chromatography, gas chromatography-mass spectrometry, and 13C-nuclear magnetic resonance showed that the type 8 capsular polysaccharide is composed of O-acetyl groups, N-acetylfucosamine, and an aminouronic acid similar to N-acetylgalactosaminouronic acid. The purified polysaccharide reacted only with type 8 antiserum in double diffusion experiments. Our analysis shows that the type 8 polysaccharide is both chemically and serologically distinct from teichoic acid and previously characterized polysaccharides of S. aureus. Images PMID:6429051

  20. Potential value of Cs-137 capsules

    SciTech Connect

    Bloomster, C.H.; Brown, D.R.; Bruno, G.A.; Hazelton, R.F.; Hendrickson, P.L.; Lezberg, A.J.; Tingey, G.L.; Wilfert, G.L.

    1985-04-01

    We determined the value of Cs-137 compared to Co-60 as a source for the irradiation of fruit (apples and cherries), pork and medical supplies. Cs-137, in the WESF capsule form, had a value of approximately $0.40/Ci as a substitute for Co-60 priced at approximately $1.00/Ci. The comparison was based on the available curies emitted from the surface of each capsule. We developed preliminary designs for fourteen irradiation facilities; seven were based on Co-60 and seven were based on Cs-137. These designs provided the basis for estimating capital and operating costs which, in turn, provided the basis for determining the value of Cs-137 relative to Co-60 in these applications. We evaluated the effect of the size of the irradiation facility on the value of Cs-137. The cost of irradiation is low compared to the value of the product. Irradiation of apples for disinfestation costs $.01 to .02 per pound. Irradiation for trichina-safe pork costs $.02 per pound. Irradiation of medical supplies for sterilization costs $.07 to .12 per pound. The cost of the irradiation source, either Co-60 or Cs-137, contributed only a minor amount to the total cost of irradiation, about 5% for the fruit and hog cases and about 20% for the medical supply cases. We analyzed the sensitivity of the irradiation costs and Cs-137 value to several key assumptions.

  1. Orbital Thermal Control of the Mercury Capsule

    NASA Technical Reports Server (NTRS)

    Weston, Kenneth C.

    1960-01-01

    The approach to orbital thermal control of the Project Mercury capsule environment is relatively unsophisticated compared with that for many unmanned satellites. This is made possible by the relatively short orbital flight of about 4 1/2 hours and by the presence of the astronaut who is able to monitor the capsule systems and compensate for undesirable thermal conditions. The general external features of the Mercury configuration as it appears in the orbital phase of flight are shown. The conical afterbody is a double-wall structure. The inner wall serves as a pressure vessel for the manned compartment, and the outer wall, of shingle type construction, acts as a radiating shield during reentry. Surface treatment of the shingles calls for a stably oxidized surface to minimize reentry temperatures. The shingles are supported by insulated stringers attached to the inner skin. Areas between stringers are insulated by blankets of Thermoflex insulation. This insulation is especially effective at high altitude due to the reduction of its thermal conductivity with decreasing pressure. As a result of the design of the afterbody for the severe reentry conditions, the heat balance on the manned compartment indicates the necessity for moderate internal cooling to compensate for the heat generation due to human and electrical sources. This cooling is achieved by the controlled vaporization of water in the cabin and astronaut-suit heat exchangers.

  2. Diamagnetically stabilized levitation control of an intraluminal magnetic capsule.

    PubMed

    Lam, Michael; Mintchev, Martin

    2009-08-01

    Controlled navigation promotes full utilization of capsule endoscopy for reliable real-time diagnosis in the gastrointestinal (GI) tract, but intermittent natural peristalsis can disturb the navigational control, destabilize the capsule and take it out of levitation. The focus of the present work was to develop an economical and effective real-time magnetic capsule-guiding system that can operate in the presence of naturally existing peristalsis while retaining navigational control. A real-size magnetic navigation system that can handle peristaltic forces of up to 1.5 N was designed utilizing the computer-aided design (CAD) system Maxwell 3D (Ansoft, Pittsburg, PA) and was verified using a small-size physical experimental setup. The proposed system contains a pair of 50 cm diameter, 10,000-turn copper electromagnets with a 10 cm x 10 cm ferrous core driven by currents of up to 300 A and can successfully maintain position control over the levitating capsule during peristalsis. The addition of bismuth diamagnetic casing for stabilizing the levitating capsule was also studied. A modeled magnetic field around the diamagnetically cased permanent magnet was shown to be redistributed aligning its interaction with the external electromagnets, thus stabilizing the levitating capsule. In summary, a custom-designed diamagnetically facilitated capsule navigation system can successfully steer an intraluminal magnet-carrying capsule. PMID:19550023

  3. 21 CFR 872.3110 - Dental amalgam capsule.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Dental amalgam capsule. 872.3110 Section 872.3110 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3110 Dental amalgam capsule. (a) Identification....

  4. 21 CFR 872.3110 - Dental amalgam capsule.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Dental amalgam capsule. 872.3110 Section 872.3110 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3110 Dental amalgam capsule. (a) Identification....

  5. Analysing intracellular deformation of polymer capsules using structured illumination microscopy

    NASA Astrophysics Data System (ADS)

    Chen, Xi; Cui, Jiwei; Sun, Huanli; Müllner, Markus; Yan, Yan; Noi, Ka Fung; Ping, Yuan; Caruso, Frank

    2016-06-01

    Understanding the behaviour of therapeutic carriers is important in elucidating their mechanism of action and how they are processed inside cells. Herein we examine the intracellular deformation of layer-by-layer assembled polymer capsules using super-resolution structured illumination microscopy (SIM). Spherical- and cylindrical-shaped capsules were studied in three different cell lines, namely HeLa (human epithelial cell line), RAW264.7 (mouse macrophage cell line) and differentiated THP-1 (human monocyte-derived macrophage cell line). We observed that the deformation of capsules was dependent on cell line, but independent of capsule shape. This suggests that the mechanical forces, which induce capsule deformation during cell uptake, vary between cell lines, indicating that the capsules are exposed to higher mechanical forces in HeLa cells, followed by RAW264.7 and then differentiated THP-1 cells. Our study demonstrates the use of super-resolution SIM in analysing intracellular capsule deformation, offering important insights into the cellular processing of drug carriers in cells and providing fundamental knowledge of intracellular mechanobiology. Furthermore, this study may aid in the design of novel drug carriers that are sensitive to deformation for enhanced drug release properties.Understanding the behaviour of therapeutic carriers is important in elucidating their mechanism of action and how they are processed inside cells. Herein we examine the intracellular deformation of layer-by-layer assembled polymer capsules using super-resolution structured illumination microscopy (SIM). Spherical- and cylindrical-shaped capsules were studied in three different cell lines, namely HeLa (human epithelial cell line), RAW264.7 (mouse macrophage cell line) and differentiated THP-1 (human monocyte-derived macrophage cell line). We observed that the deformation of capsules was dependent on cell line, but independent of capsule shape. This suggests that the mechanical forces

  6. Analysis of Fission Products on the AGR-1 Capsule Components

    SciTech Connect

    Paul A. Demkowicz; Jason M. Harp; Philip L. Winston; Scott A. Ploger

    2013-03-01

    The components of the AGR-1 irradiation capsules were analyzed to determine the retained inventory of fission products in order to determine the extent of in-pile fission product release from the fuel compacts. This includes analysis of (i) the metal capsule components, (ii) the graphite fuel holders, (iii) the graphite spacers, and (iv) the gas exit lines. The fission products most prevalent in the components were Ag-110m, Cs 134, Cs 137, Eu-154, and Sr 90, and the most common location was the metal capsule components and the graphite fuel holders. Gamma scanning of the graphite fuel holders was also performed to determine spatial distribution of Ag-110m and radiocesium. Silver was released from the fuel components in significant fractions. The total Ag-110m inventory found in the capsules ranged from 1.2×10 2 (Capsule 3) to 3.8×10 1 (Capsule 6). Ag-110m was not distributed evenly in the graphite fuel holders, but tended to concentrate at the axial ends of the graphite holders in Capsules 1 and 6 (located at the top and bottom of the test train) and near the axial center in Capsules 2, 3, and 5 (in the center of the test train). The Ag-110m further tended to be concentrated around fuel stacks 1 and 3, the two stacks facing the ATR reactor core and location of higher burnup, neutron fluence, and temperatures compared with Stack 2. Detailed correlation of silver release with fuel type and irradiation temperatures is problematic at the capsule level due to the large range of temperatures experienced by individual fuel compacts in each capsule. A comprehensive Ag 110m mass balance for the capsules was performed using measured inventories of individual compacts and the inventory on the capsule components. For most capsules, the mass balance was within 11% of the predicted inventory. The Ag-110m release from individual compacts often exhibited a very large range within a particular capsule.

  7. Vesta is not an intact protoplanet

    NASA Astrophysics Data System (ADS)

    Consolmagno, G.; Turrini, D.; Golabek, G.; Svetsov, V.; Sirono, S.; Tsiganis, K.

    2014-07-01

    The Dawn mission was designed to explore ''remnant intact protoplanets from the earliest epoch of solar system formation'' [1]. However, models of Vesta composed of an iron core, olivine mantle, and HED crust in chondritic proportions cannot match the joint constraints from Dawn [1] of Vesta's density, core size, and the extremely limited presence of exposed olivine on its surface. Vesta has a mean density of 3456 kg/m3 and its surface composition is well matched by howardites. The Dawn gravity data suggest a nickel-iron core of radius 110 km and density 7500--7800 kg/m3. The Rheasilvia impact basin, formed within a pre-existing large basin, Veneneia, should have excavated material from a depth of 50 km to 80 km or more below Vesta's surface [2]. If the howardite crust were thinner than 50--80 km, a significant amount of olivine-rich material, derived from depth, would have been exposed within this basin; models suggest that olivine would also be distributed both on Vesta's surface and in space as meteorite-source Vestoids. Such olivine is rare on Vesta, among the Vestoids, or in our meteorite collection. Vesta's density is similar to an L chondrite, but the Na and K abundances in Vesta are strongly depleted compared to chondrites and the average metal content of an L chondrite, 8.4% by mass, would give a core radius less than 90 km. A 110 km radius metallic core, via the Dawn data, represents 15% of Vesta's mass. The Mg/Al ratio in cosmic abundances is about 10:1, but roughly 1:1 within the eucrites; thus if Vesta started with cosmic abundances, the eucrites can only represent 10% of the parent body total mass. Likewise the 10 x chondritic rare earth trace elements (REE) abundance seen in most eucrites demands that, regardless of formation mechanism, these basalts were crystallized from a melt representing 10% of the mass of the source region [3]. Thus the howardite crust of a chondritic HED parent body, mixing all the available eucritic and diogenitic material

  8. Three-dimensional simulations of Nova capsule implosion experiments

    SciTech Connect

    Marinak, M.M.; Tipton, R.E.; Landen, O.L.

    1995-11-01

    Capsule implosion experiments carried out on the Nova laser are simulated with the three-dimensional HYDRA radiation hydrodynamics code. Simulations of ordered near single mode perturbations indicate that structures which evolve into round spikes can penetrate farthest into the hot spot. Bubble-shaped perturbations can burn through the capsule shell fastest, however, causing even more damage. Simulations of a capsule with multimode perturbations shows spike amplitudes evolving in good agreement with a saturation model during the deceleration phase. The presence of sizable low mode asymmetry, caused either by drive asymmetry or perturbations in the capsule shell, can dramatically affect the manner in which spikes approach the center of the hot spot. Three-dimensional coupling between the low mode shell perturbations intrinsic to Nova capsules and the drive asymmetry brings the simulated yields into closer agreement with the experimental values.

  9. Aerobic methane emissions from stinkweed (Thlaspi arvense) capsules

    PubMed Central

    Qaderi, Mirwais M; Reid, David M

    2014-01-01

    Aerobic methane (CH4) emission from plant vegetative parts has been confirmed by many studies. However, the origin of aerobic CH4 from plants and its emission from reproductive parts have not been well documented. We determined the effects of developmental stages (early, mid, late) and incubation conditions (darkness, dim light, bright light) on CH4 emissions from stinkweed (Thlaspi arvense) capsules. We found that CH4 emissions from capsules varied with developmental stage and incubation light. Methane emission was highest for the late harvested capsules and for those incubated under lower (dim) light condition. Our results also showed a significant negative correlation between CH4 emission and capsule moisture content. We conclude that CH4 emissions vary with capsule age and diurnal light environment. PMID:25482797

  10. 56. POWDER MAGAZINE, VIEW OF INTACT WOOD SHEATHING ON THE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    56. POWDER MAGAZINE, VIEW OF INTACT WOOD SHEATHING ON THE SOUTHWEST REAR VENTILATION PASSAGE. (SHEATHING HELP CONTROL HUMIDITY AND DECREASE DANGER OF MAETAL STRIKING STONE AND SPARKING.) - Fort Monroe, Fortress, Hampton, Hampton, VA

  11. Primate lens capsule elasticity assessed using Atomic Force Microscopy.

    PubMed

    Ziebarth, Noël M; Arrieta, Esdras; Feuer, William J; Moy, Vincent T; Manns, Fabrice; Parel, Jean-Marie

    2011-06-01

    The purpose of this project is to measure the elasticity of the human and non-human primate lens capsule at the microscopic scale using Atomic Force Microscopy (AFM). Elasticity measurements were performed using AFM on the excised anterior lens capsule from 9 cynomolgus monkey (5.9-8.0 years), 8 hamadryas baboon (2.8-10.1 years), and 18 human lenses (33-79 years). Anterior capsule specimens were obtained by performing a 5 mm continuous curvilinear capsulorhexis and collecting the resulting disk of capsular tissue. To remove the lens epithelial cells the specimen was soaked in 0.1% trypsin and 0.02% EDTA for 5 min, washed, and placed on a Petri dish and immersed in DMEM. Elasticity measurements of the capsule were performed with a laboratory-built AFM system custom designed for force measurements of ophthalmic tissues. The capsular specimens were probed with an AFM cantilever tip to produce force-indentation curves for each specimen. Young's modulus was calculated from the force-indentation curves using the model of Sneddon for a conical indenter. Young's modulus of elasticity was 20.1-131 kPa for the human lens capsule, 9.19-117 kPa for the cynomolgus lens capsule, and 13.1-62.4 kPa for the baboon lens capsule. Young's modulus increased significantly with age in humans (p = 0.03). The age range of the monkey and baboon samples was not sufficient to justify an analysis of age dependence. The capsule elasticity of young humans (<45 years) was not statistically different from that of the monkey and baboon. In humans, there is an increase in lens capsule stiffness at the microscale that could be responsible for an increase in lens capsule bulk stiffness.

  12. α-Amylase-assisted extraction of polysaccharides from Panax ginseng.

    PubMed

    Sun, Lin; Wu, Di; Ning, Xin; Yang, Guang; Lin, Ziheng; Tian, Meihong; Zhou, Yifa

    2015-04-01

    In this paper, α-amylase-assisted extraction was used to isolate the polysaccharide that remained in hot water-extracted ginseng. The yield of the polysaccharide was 9.0%, almost equal to that of the hot water-extracted polysaccharide. Using anion exchange and gel permeation chromatography, the polysaccharide was fractionated into a neutral polysaccharide fraction and six pectic fractions. The neutral fraction accounted for 76% of the polysaccharide and contained both amylopectin and amylose. The pectic polysaccharide fractions were identified to be arabinogalactan, type-I rhamnogalacturonan and homogalacturonan-type pectin by high-performance liquid chromatography, Fourier transform-infrared and nuclear magnetic resonance analysis. Structural and lymphocyte proliferation activity results showed that these polysaccharides were different from those extracted by hot water, indicating that ginseng contains complex polysaccharides with diverse structures, which results in its diverse pharmacological activities. The α-amylase-assisted extraction is a novel method for preparing ginseng polysaccharides and could be applied toward the further study and exploration of ginseng. These findings provide technical and theoretical support for ginseng pharmacology.

  13. Efficacy of Zhuling polyporus polysaccharide with BCG to inhibit bladder carcinoma.

    PubMed

    Zhang, Guo-Wei; Qin, Gui-Fang; Han, Bo; Li, Cai-Xia; Yang, Hong-Gai; Nie, Pi-Hu; Zeng, Xing

    2015-03-15

    There is growing interest in reducing Bacille Calmette-Guerin (BCG) side effects while keeping intact its therapeutic efficacy. In the present study, we evaluated the efficacy of Sclerotia of Polyporus umbellatus FRIES (Zhuling) and its main ingredient Polyporus Polysaccharide (PPS) to attenuate side effects of BCG therapy in vivo. The results show that bladder cancer development in model rats exhibited significantly reduced cancer invasiveness with Zhuling PPS combined with BCG. Flow cytometric (FCM) analysis showed expression of costimulatory molecules CD86, CD40, and TLR4/CD14 significantly increased with Zhuling PPS in combination with BCG. Similarly, immunohistochemical analysis revealed stronger CD86 and CD40 staining. Our findings show Zhuling PPS strongly reduced side effects and displayed synergistic effects during BCG instillation in rat bladder cancer models. The findings also suggest that the attenuation effect may result from direct activation of dendritic cell (DC) TLR4.

  14. Strategy to identify and quantify polysaccharide gums in gelled food concentrates.

    PubMed

    Grün, Christian H; Sanders, Peter; van der Burg, Monique; Schuurbiers, Eric; van Adrichem, Linda; van Velzen, Ewoud J J; de Roo, Niels; Brunt, Kommer; Westphal, Yvonne; Schols, Henk A

    2015-01-01

    A strategy for the unambiguous identification and selective quantification of xanthan gum and locust bean gum (LBG) in gelled food concentrates is presented. DNA detection by polymerase chain reaction (PCR) showed to be a fast, sensitive, and selective method that can be used as a first screening tool in intact gelled food concentrates. An efficient isolation procedure is described removing components that may interfere with subsequent analyses. NMR spectroscopy enabled the direct identification of xanthan gum and the discrimination between different galactomannans in the isolated polysaccharide fraction. An enzymatic fingerprinting method using endo-β-mannanase, in addition to being used to differentiate between galactomannans, was developed into a selective, quantitative method for LBG, whereas monosaccharide analysis was used to quantify xanthan gum. Recoveries for xanthan gum and LBG were 87% and 70%, respectively, with in-between day relative standard deviations below 20% for xanthan gum and below 10% for LBG. PMID:25053026

  15. Francisella tularensis Schu S4 O-antigen and capsule biosynthesis gene mutants induce early cell death in human macrophages.

    PubMed

    Lindemann, Stephen R; Peng, Kaitian; Long, Matthew E; Hunt, Jason R; Apicella, Michael A; Monack, Denise M; Allen, Lee-Ann H; Jones, Bradley D

    2011-02-01

    Francisella tularensis is capable of rampant intracellular growth and causes a potentially fatal disease in humans. Whereas many mutational studies have been performed with avirulent strains of Francisella, relatively little has been done with strains that cause human disease. We generated a near-saturating transposon library in the virulent strain Schu S4, which was subjected to high-throughput screening by transposon site hybridization through primary human macrophages, negatively selecting 202 genes. Of special note were genes in a locus of the Francisella chromosome, FTT1236, FTT1237, and FTT1238. Mutants with mutations in these genes demonstrated significant sensitivity to complement-mediated lysis compared with wild-type Schu S4 and exhibited marked defects in O-antigen and capsular polysaccharide biosynthesis. In the absence of complement, these mutants were phagocytosed more efficiently by macrophages than wild-type Schu S4 and were capable of phagosomal escape but exhibited reduced intracellular growth. Microscopic and quantitative analyses of macrophages infected with mutant bacteria revealed that these macrophages exhibited signs of cell death much earlier than those infected with Schu S4. These data suggest that FTT1236, FTT1237, and FTT1238 are important for polysaccharide biosynthesis and that the Francisella O antigen, capsule, or both are important for avoiding the early induction of macrophage death and the destruction of the replicative niche.

  16. A comparative study on liquid core formulation on the diameter on the alginate capsules

    NASA Astrophysics Data System (ADS)

    Ong, Hui-Yen; Lee, Boon-Beng; Radzi, AkmalHadi Ma'; Zakaria, Zarina; Chan, Eng-Seng

    2015-08-01

    Liquid core capsule has vast application in biotechnology related industries such as pharmaceutical, medical, agriculture and food. Formulation of different types of capsule was important to determine the performance of the capsule. Generally, the liquid core capsule with different formulations generated different size of capsule.Therefore, the aim of this project is to investigate the effect of different liquid core solution formulations on the diameter of capsule. The capsule produced by extruding liquid core solutions into sodium alginate solution. Three types of liquid core solutions (chitosan, xanthan gum, polyethylene glycol (PEG)) were investigated. The results showed that there is significant change in capsule diameter despite in different types of liquid core solution were used and a series of capsule range in diameter of 3.1 mm to 4.5 mm were produced. Alginate capsule with chitosan formulation appeared to be the largest capsule among all.

  17. Dissolution test for silymarin tablets and capsules.

    PubMed

    Campodónico, A; Collado, E; Ricci, R; Pappa, H; Segall, A; Pizzorno, M T

    2001-01-01

    Silybine (SBN), isosilybine (ISBN), silycristine (SCN), silydianine (SDN), and taxifoline (TXF) are the main active flavonoids commonly found in the dried fruits of Silybum marianum, Gaertner (Compositae). Concentrations of these compounds, except TXF, are usually expressed together as silymarin content. This paper describes a simple dissolution test developed to estimate silymarin (Sl) in pharmaceutical formulations. Five commercial products were tested using this new method (including tablets, sugar tablets, and capsules): two from Argentina, one from Brazil, one from Spain, and one from Italy. Results demonstrated that, provided the dosage form disintegrates, amounts dissolved range from 50 to 90% of the labeled value. Products were analyzed by high performance liquid chromatography (HPLC) and UV spectrophotometry.

  18. Gastrointestinal motility revisited: The wireless motility capsule

    PubMed Central

    Farmer, Adam D; Scott, S Mark

    2013-01-01

    Introduction The wireless motility capsule (WMC) is a novel ambulatory technology that concurrently measures intraluminal pH, temperature, and pressure as it traverses the gastrointestinal tract. Objectives We aim to provide a concise summary of the WMC, detailing the procedure for its administration and the parameters it records. We also review the evidence that has validated the WMC against other methods currently regarded as ‘gold standard’. Conclusions The WMC offers a number of advantages over and above current techniques, especially with respect to patient tolerability, safety, and standardization. The WMC represents a considerable enhancement of the researchers’ and clinicians’ investigatory armamentarium. If this technology becomes widely adopted, coupled with international consensus upon the interpretation of physiological data derived therein, it may herald a new and exciting era in gastrointestinal physiology. PMID:24917991

  19. Genesis Capsule Yields Solar Wind Samples

    NASA Astrophysics Data System (ADS)

    Wiens, Roger C.; Burnett, Donald S.; Stansbery, Eileen K.; McNamara, Karen M.

    2004-11-01

    NASA's Genesis capsule, carrying the first samples ever returned from beyond the Moon, took a hard landing in the western Utah desert on 8 September after its parachutes failed to deploy. Despite the impact, estimated at 310 km per hour, some valuable solar wind collector materials have been recovered. With these samples, the Genesis team members are hopeful that nearly all of the primary science goals may be met. The Genesis spacecraft was launched in August 2001 to collect and return samples of solar wind for precise isotopic and elemental analysis. The spacecraft orbited the Earth-Sun Lagrangian point (L1), ~1.5 million km sunward of the Earth, for 2.3 years. It exposed ultrapure materials-including wafers of silicon, silicon carbide, germanium, chemically deposited diamond, gold, aluminum, and metallic glass-to solar wind ions, which become embedded within the substrates' top 100 nm of these materials.

  20. Environmental Fluid Dynamics in Space Capsule

    NASA Astrophysics Data System (ADS)

    Yin, Zhaohua

    Environmental fluid dynamics began to get more and more concern recently because of its effects on indoor air quality and ventilation strategy. Our research is trying to use the tools of Environmental fluid dynamics to investigate the life support system (LSS) for manned space flight, especially for future long-term planetary exploration flight (permanent space station and lunar base, space greenhouse of controlled ecological life support systems (CELSS) etc.). The PIV technique will be adopted to obtain the velocity of the flow field and dyed fluids to capture the temperature field. On the other hand, we will use the commercial software (FLUENT) to numerical simulate the same problem. The results in this work can be used to improve the ventilation efficiency, reduce the energy costs and try to make the air in space capsule less effluvial.

  1. Multilevel wireless capsule endoscopy video segmentation

    NASA Astrophysics Data System (ADS)

    Hwang, Sae; Celebi, M. Emre

    2010-03-01

    Wireless Capsule Endoscopy (WCE) is a relatively new technology (FDA approved in 2002) allowing doctors to view most of the small intestine. WCE transmits more than 50,000 video frames per examination and the visual inspection of the resulting video is a highly time-consuming task even for the experienced gastroenterologist. Typically, a medical clinician spends one or two hours to analyze a WCE video. To reduce the assessment time, it is critical to develop a technique to automatically discriminate digestive organs and shots each of which consists of the same or similar shots. In this paper a multi-level WCE video segmentation methodology is presented to reduce the examination time.

  2. High speed receiver for capsule endoscope.

    PubMed

    Woo, S H; Yoon, K W; Moon, Y K; Lee, J H; Park, H J; Kim, T W; Choi, H C; Won, C H; Cho, J H

    2010-10-01

    In this study, a high-speed receiver for a capsule endoscope was proposed and implemented. The proposed receiver could receive 20 Mbps data that was sufficient to receive images with a higher resolution than conventional receivers. The receiver used a 1.2 GHz band to receive radio frequency (RF) signal, and demodulated the signal to an intermediate frequency (IF) stage (150 MHz). The demodulated signal was amplified, filtered, and under-sampled by a high-speed analog-to-digital converter (ADC). In order to decode the under-sampled data in real time, a simple frequency detection algorithm was selected and was implemented by using a FPGA. The implemented system could receive 20 Mbps data.

  3. Cryptococcus neoformans Requires the ESCRT Protein Vps23 for Iron Acquisition from Heme, for Capsule Formation, and for Virulence

    PubMed Central

    Hu, Guanggan; Caza, Mélissa; Cadieux, Brigitte; Chan, Vivienne; Liu, Victor

    2013-01-01

    Iron availability is a key regulator of virulence factor elaboration in Cryptococcus neoformans, the causative agent of fungal meningoencephalitis in HIV/AIDS patients. In addition, iron is an essential nutrient for pathogen proliferation in mammalian hosts but little is known about the mechanisms of iron sensing and uptake in fungal pathogens that attack humans. In this study, we mutagenized C. neoformans by Agrobacterium-mediated T-DNA insertion and screened for mutants with reduced growth on heme as the sole iron source. Among 34 mutants, we identified a subset with insertions in the gene for the ESCRT-I (endosomal sorting complex required for transport) protein Vps23 that resulted in a growth defect on heme, presumably due to a defect in uptake via endocytosis or misregulation of iron acquisition from heme. Remarkably, vps23 mutants were also defective in the elaboration of the cell-associated capsular polysaccharide that is a major virulence factor, while overexpression of Vps23 resulted in cells with a slightly enlarged capsule. These phenotypes were mirrored by a virulence defect in the vps23 mutant in a mouse model of cryptococcosis and by hypervirulence of the overexpression strain. Overall, these results reveal an important role for trafficking via ESCRT functions in both heme uptake and capsule formation, and they further reinforce the connection between iron and virulence factor deployment in C. neoformans. PMID:23132495

  4. Capsule HRB-15B postirradiation examination report

    SciTech Connect

    Ketterer, J.W.; Bullock, R.E.

    1981-06-01

    Capsule HRB-15B design tested 184 thin graphite trays containing unbonded fuel particles to peak exposures of 6.6 x 10/sup 25/ n/m/sup 2/ (E > 29 fJ)/sub HTGR/ fast fluence, approx. 27% fissions per initial metal atom (FIMA) fissile burnup, and 6% FIMA fertile burnup at nominal time-averaged temperatures of 815 to 915/sup 0/C. The capsule tested a variety of low-enriched uranium (approx. 19.5% U-235) fissile particle types, including UC/sub 2/, UC/sub x/O/sub y/, UO/sub 2/, zirconium-buffered UO/sub 2/ (referred to in this report as UO/sub 2//sup *), and 1:1(Th,U)O/sub 2/ with both TRISO and silicon-BISO coatings. All fertile particles were ThO/sub 2/ with BISO, silicon-BISO, or TRISO coatings. The findings indicated that all TRISO particles retained virtually all of their fission product inventories, except small quantities of silver, at these irradiation temperatures, while some of the silicon-BISO particles released significant amounts of both silver and cesium. No kernel migration, pressure vessel, or outer pyrolytic carbon (OPyC) failures were observed in the fuel particles, which had total diameters of < 900 ..mu..m; however, the incidence of failed OPyC coatings was found to increase with particle size in the TRISO inert particles, which had diameters of 1000 to 1200 ..mu..m. UO/sub 2//sup */ particles exhibited no detrimental irradiation effects, but they contained pure carbon precipitates in the kernels after irradiation which were not observed in the undoped UO/sub 2/ particles. Postirradiation examination revealed no differences in the irradiation performance of three UC/sub x/O/sub y/ kernel types with varying oxygen/uranium ratios.

  5. Effects of selenizing angelica polysaccharide and selenizing garlic polysaccharide on immune function of murine peritoneal macrophage.

    PubMed

    Gao, Zhenzhen; Liu, Kuanhui; Tian, Weijun; Wang, Hongchao; Liu, Zhenguang; Li, Youying; Li, Entao; Liu, Cui; Li, Xiuping; Hou, Ranran; Yue, Chanjuan; Wang, Deyun; Hu, Yuanliang

    2015-07-01

    The effects of two selenizing polysaccharides (sCAP2 and sGPS6) on immune function of murine peritoneal macrophages taking two non-selenizing polysaccharides (CAP and GPS) and modifier Na2SeO3 as control. In vitro test, the changes of selenizing polysaccharides, non-selenizing polysaccharides and Na2SeO3 on murine macrophages function were evaluated by phagocytosis and nitric oxide (NO) secretion tests. In vivo test, the mice were injected respectively with 0.2, 0.4 and 0.6 mg of sCAP2, sGPS6, CAP and GPS, or Na2SeO3 80 μg or normal saline 0.4 mL. The peritoneal macrophages were collected and cultured to determine the contents of TNF-α, IL-6 and IL-10 in supernatants by enzyme-linked immunosorbent assay. The results showed that sCAP2 and sGPS6 could significantly promote the phagocytosis and secretion of NO and three cytokines of macrophages in comparison with CAP and GPS. sCAP2 possessed the strongest activity. This indicates that selenylation modification can further improve the immune-enhancing activity of polysaccharide, and sCAP2 could be as a new immunopotentiator.

  6. POLYPEPTIDE AND POLYSACCHARIDE PROCESSING IN HYPERTHERMOPHILIC MICROORGANISMS

    SciTech Connect

    KELLY, ROBERT M.

    2008-12-22

    This project focused on the microbial physiology and biochemistry of heterotrophic hyperthermophiles with respect to mechanisms by which these organisms process polypeptides and polysaccharides under normal and stressed conditions. Emphasis is on two model organisms, for which completed genome sequences are available: Pyrococcus furiosus (growth Topt of 98°C), an archaeon, and Thermotoga maritima (growth Topt of 80°C), a bacterium. Both organisms are obligately anaerobic heterotrophs that reduce sulfur facultatively. Whole genome cDNA spotted microarrays were used to follow transcriptional response to a variety of environmental conditions in order to identify genes encoding proteins involved in the acquisition, synthesis, processing and utilization of polypeptides and polysaccharides. This project provided new insights into the physiological aspects of hyperthermophiles as these relate to microbial biochemistry and biological function in high temperature habitats. The capacity of these microorganisms to produce biohydrogen from renewable feedstocks makes them important for future efforts to develop biofuels.

  7. A serogroup A meningococcal polysaccharide vaccine

    PubMed Central

    Erwa, H. H.; Haseeb, M. A.; Idris, A. A.; Lapeyssonnie, L.; Sanborn, W. R.; Sippel, J. E.

    1973-01-01

    Vaccination against cerebrospinal meningitis (CSM) has regained interest with the use of capsular polysaccharides (or polyosides) of the meningococcus as specific immunizing agents. These compounds proved to be effective in the USA against meningitis caused by Neisseria meningitidis serotype C. This study considers whether the polysaccharides of the serotype A meningococcus, which is prevalent in the African CSM belt, could be protective in epidemic conditions. Taking advantage of the usual seasonal peak of CSM cases, controlled field trials were undertaken in the Sudan early in 1973. 21 640 persons were vaccinated, half of them with a meningococcal polyoside A vaccine and the other half with tetanus toxoid as a placebo. In the former group there were no cases of meningitis, whereas in the latter 10 cases were reported, of which 7 were confirmed by laboratory tests. These studies indicate that the meningococcal polyoside A vaccine is efficient in epidemic conditions and could be used to control outbreaks of meningococcal meningitis. PMID:4211056

  8. The capsule polymerase CslB of Neisseria meningitidis serogroup L catalyzes the synthesis of a complex trimeric repeating unit comprising glycosidic and phosphodiester linkages.

    PubMed

    Litschko, Christa; Romano, Maria Rosaria; Pinto, Vittoria; Claus, Heike; Vogel, Ulrich; Berti, Francesco; Gerardy-Schahn, Rita; Fiebig, Timm

    2015-10-01

    Neisseria meningitidis is a human pathogen causing bacterial meningitis and sepsis. The capsular polysaccharide surrounding N. meningitidis is a major virulence factor. The capsular polysaccharide consists of polyhexosamine phosphates in N. meningitidis serogroups A and X. The capsule polymerases (CPs) of these serogroups are members of the Stealth protein family comprising d-hexose-1-phosphate transferases from bacterial and protozoan pathogens. CslA, one of two putative CPs of the pathophysiologically less relevant N. meningitidis serogroup L, is one of the smallest known Stealth proteins and caught our attention for structure-function analyses. Because the N. meningitidis serogroup L capsule polymer consists of a trimeric repeating unit ([→3)-β-d-GlcNAc-(1→3)-β-d-GlcNAc-(1→3)-α-d-GlcNAc-(1→OPO3→]n), we speculated that the two predicted CPs (CslA and CslB) work together in polymer production. Consequently, both enzymes were cloned, overexpressed, and purified as recombinant proteins. Contrary to our expectation, enzymatic testing identified CslB to be sufficient to catalyze the synthesis of the complex trimeric N. meningitidis serogroup L capsule polymer repeating unit. No polymerase activity was detected for CslA, although the enzyme facilitated the hydrolysis of UDP-GlcNAc. Bioinformatics analyses identified two glycosyltransferase (GT) domains in CslB. The N-terminal domain modeled with 100% confidence onto a number of GT-A folded proteins, whereas the C-terminal domain modeled with 100% confidence onto TagF, a GT-B folded teichoic acid polymerase from Staphylococcus epidermidis. Amino acid positions known to have critical catalytic functions in the template proteins were conserved in CslB, and their point mutation abolished enzyme activity. CslB represents an enzyme of so far unique complexity regarding both the catalyzed reaction and enzyme architecture.

  9. Microbial extracellular polysaccharides and plagioclase dissolution

    NASA Astrophysics Data System (ADS)

    Welch, S. A.; Barker, W. W.; Banfield, J. F.

    1999-05-01

    Bytownite feldspar was dissolved in batch reactors in solutions of starch (glucose polymer), gum xanthan (glucose, mannose, glucuronic acid), pectin (poly-galacturonic acid), and four alginates (mannuronic and guluronic acid) with a range of molecular weights (low, medium, high and uncharacterized) to evaluate the effect of extracellular microbial polymers on mineral dissolution rates. Solutions were analyzed for dissolved Si and Al as an indicator of feldspar dissolution. At neutral pH, feldspar dissolution was inhibited by five of the acid polysaccharides, gum xanthan, pectin, alginate low, alginate medium, alginate high, compared to an organic-free control. An uncharacterized alginate substantially enhanced both Si and Al release from the feldspar. Starch, a neutral polysaccharide, had no apparent effect. Under mildly acidic conditions, initial pH ≈ 4, all of the polymers enhanced feldspar dissolution compared to the inorganic controls. Si release from feldspar in starch solution exceeded the control by a factor of three. Pectin and gum xanthan increased feldspar dissolution by a factor of 10, and the alginates enhanced feldspar dissolution by a factor of 50 to 100. Si and Al concentrations increased with time, even though solutions were supersaturated with respect to several possible secondary phases. Under acidic conditions, initial pH ≈ 3, below the pK a of the carboxylic acid groups, dissolution rates increased, but the relative increase due to the polysaccharides is lower, approximately a factor of two to ten. Microbial extracellular polymers play a complex role in mineral weathering. Polymers appear to inhibit dissolution under some conditions, possibly by irreversibly binding to the mineral surfaces. The extracellular polysaccharides can also enhance dissolution by providing protons and complexing with ions in solution.

  10. Chemoenzymatic synthesis of the bacterial polysaccharide repeating unit undecaprenyl pyrophosphate and its analogs.

    PubMed

    Li, Lei; Woodward, Robert L; Han, Weiqing; Qu, Jingyao; Song, Jing; Ma, Cheng; Wang, Peng G

    2016-07-01

    Polysaccharides are essential and immunologically relevant components of bacterial cell walls. These biomolecules can be found covalently attached to lipids (e.g., O-polysaccharide (PS) contains undecaprenyl and lipopolysaccharide (LPS) contains lipid A) or noncovalently associated with cell wells (e.g., capsular PS (CPS)). Although extensive genetic studies have indicated that the Wzy-dependent biosynthetic pathway is primarily responsible for producing such polysaccharides, in vitro biochemical studies are needed to determine, for example, which gene product is responsible for catalyzing each step in the pathway, and to reveal molecular details about the Wzx translocase, Wzy polymerase and O-PS chain-length determinant. Many of these biochemical studies require access to a structurally well-defined PS repeating unit undecaprenyl pyrophosphate (RU-PP-Und), the key building block in this pathway. We describe herein the chemoenzymatic synthesis of Escherichia coli (serotype O157) RU-PP-Und. This involves (i) chemical synthesis of precursor N-acetyl-D-galactosamine (GalNAc)-PP-Und (2 weeks) and (ii) enzymatic extension of the precursor to produce RU-PP-Und (2 weeks). Undecaprenyl phosphate and peracetylated GalNAc-1-phosphate are prepared from commercially available undecaprenol and peracetylated GalNAc. The chemical coupling of these two products, followed by structural confirmation (mass spectrometry and NMR) and deprotection, generates GalNAc-PP-Und. This compound is then sequentially modified by enzymes in the E. coli serotype O157 (E. coli O157) O-PS biosynthetic pathway. Three glycosyltransferases (GTs) are involved (WbdN, WbdO and WbdP) and they transfer glucose (Glc), L-fucose (L-Fuc) and N-acetylperosamine (PerNAc) onto GalNAc-PP-Und to form the intact RU-PP-Und in a stepwise manner. Final compounds and intermediates are confirmed by mass spectrometry. The procedure can be adapted to the synthesis of analogs with different PS or lipid moieties. PMID:27336706

  11. Adhesion and detachment of a capsule in axisymmetric flow

    NASA Astrophysics Data System (ADS)

    Keh, M. P.; Leal, L. G.

    2016-05-01

    The adhesion and detachment of a capsule on a solid boundary surface is studied via a combination of scaling theory and numerical simulation and the behavior is compared and contrasted with a vesicle. It is shown that the dominant physical property for both capsules and vesicles is the area dilation modulus Ks of the membrane. The nonzero shear modulus Gs for capsules increases the resistance to deformation and thus decreases slightly the equilibrium contact radius for an adhered capsule compared to an adhered vesicle. The detachment process in this study is due to an external axisymmetric flow. Unlike a rigid body that must be pulled away without change of shape, capsules (and vesicles) almost always detach dominantly by peeling in which the contact radius decreases but the minimum separation distance does not change until the final moments of detachment. Compared to a vesicle with the same Ks, a capsule maintains a more compact shape and is harder to elongate under a given external flow. Hence, the detachment process is slower for capsules compared to vesicles with the same Ks.

  12. Effects of powder flow properties on capsule filling weight uniformity.

    PubMed

    Osorio, Juan G; Muzzio, Fernando J

    2013-09-01

    Filling capsules with the right amount of powder ingredients is an important quality parameter. The purpose of this study was to develop effective laboratory methods for characterizing flow properties of pharmaceutical powder blends and correlating such properties to weight variability in filled capsules. The methods used for powder flow characterization were bulk and tapped density, gravitational displacement rheometer (GDR) flow index, Freeman Technology V.4 (FT4) powder rheometer compressibility, FT4 basic flow energy (BFE), and cohesion parameters [cohesion, (C) and flow factor (ffc)] measured in a shear cell also using the FT4. Capsules were filled using an MG2-G140 continuous nozzle dosator capsule-filling machine. Powder flow properties were the most predominant factors affecting the weight and weight variability in the filled capsules. Results showed that the weight variability decreased with increasing bulk and tapped density, ffc and BFE, while the weight variability increased with increasing compressibility, cohesion and GDR flow index. Powder flow properties of the final blends were significantly correlated to the final capsule weight and weight variability of the filled capsules.

  13. Magnetic Resonance Imaging of Adhesive Capsulitis: Correlation with Clinical Staging

    PubMed Central

    Ciavarra, Gina A.; Hannafin, Jo A.; Cordasco, Frank A.; Potter, Hollis G.

    2008-01-01

    The purpose of this study was to evaluate non-contrast magnetic resonance imaging (MRI) findings of adhesive capsulitis and correlate them with clinical stages of adhesive capsulitis. This will hopefully define a role for shoulder MR imaging in the diagnosis of adhesive capsulitis as well as in potentially directing appropriate treatment. Forty-seven consecutive non-contrast magnetic resonance imaging examinations of 46 patients with a clinical diagnosis of adhesive capsulitis were retrospectively reviewed and correlated with clinical staging. Specific MRI criteria correlated with the clinical stage of adhesive capsulitis, including the thickness and signal intensity of the joint capsule and synovium as well as the presence and severity of scarring in the rotator interval. Routine MRI of the shoulder without intraarticular administration of gadolinium can be used to diagnose all stages of adhesive capsulitis, including stage 1, where findings may be subtle on clinical examination. We believe that future studies assessing the role of MRI in guiding the initiation of appropriate treatment should be undertaken. PMID:18815860

  14. Cell cycle constraints on capsulation and bacteriophage susceptibility

    PubMed Central

    Ardissone, Silvia; Fumeaux, Coralie; Bergé, Matthieu; Beaussart, Audrey; Théraulaz, Laurence; Radhakrishnan, Sunish Kumar; Dufrêne, Yves F; Viollier, Patrick H

    2014-01-01

    Despite the crucial role of bacterial capsules in pathogenesis, it is still unknown if systemic cues such as the cell cycle can control capsule biogenesis. In this study, we show that the capsule of the synchronizable model bacterium Caulobacter crescentus is cell cycle regulated and we unearth a bacterial transglutaminase homolog, HvyA, as restriction factor that prevents capsulation in G1-phase cells. This capsule protects cells from infection by a generalized transducing Caulobacter phage (φCr30), and the loss of HvyA confers insensitivity towards φCr30. Control of capsulation during the cell cycle could serve as a simple means to prevent steric hindrance of flagellar motility or to ensure that phage-mediated genetic exchange happens before the onset of DNA replication. Moreover, the multi-layered regulatory circuitry directing HvyA expression to G1-phase is conserved during evolution, and HvyA orthologues from related Sinorhizobia can prevent capsulation in Caulobacter, indicating that alpha-proteobacteria have retained HvyA activity. DOI: http://dx.doi.org/10.7554/eLife.03587.001 PMID:25421297

  15. Emerging Issues and Future Developments in Capsule Endoscopy

    PubMed Central

    Slawinski, Piotr R.; Obstein, Keith L.; Valdastri, Pietro

    2015-01-01

    Capsule endoscopy (CE) has transformed from a research venture into a widely used clinical tool and the primary means for diagnosing small bowel pathology. These orally administered capsules traverse passively through the gastrointestinal tract via peristalsis and are used in the esophagus, stomach, small bowel, and colon. The primary focus of CE research in recent years has been enabling active CE manipulation and extension of the technology to therapeutic functionality; thus, widening the scope of the procedure. This review outlines clinical standards of the technology as well as recent advances in CE research. Clinical capsule applications are discussed with respect to each portion of the gastrointestinal tract. Promising research efforts are presented with an emphasis on enabling active capsule locomotion. The presented studies suggest, in particular, that the most viable solution for active capsule manipulation is actuation of a capsule via exterior permanent magnet held by a robot. Developing capsule procedures adhering to current healthcare standards, such as enabling a tool channel or irrigation in a therapeutic device, is a vital phase in the adaptation of CE in the clinical setting. PMID:26028956

  16. Elastic capsule deformation in general irrotational linear flows

    PubMed Central

    Szatmary, Alex C.; Eggleton, Charles D.

    2012-01-01

    Knowledge of the response of elastic capsules to imposed fluid flow is necessary for predicting deformation and motion of biological cells and synthetic capsules in microfluidic devices and in the microcirculation. Capsules have been studied in shear, planar extensional, and axisymmetric extensional flows. Here, the flow gradient matrix of a general irrotational linear flow is characterized by two parameters, its strain rate, defined as the maximum of the principal strain rates, and by a new term, q, the difference in the two lesser principal strain rates, scaled by the maximum principal strain rate; this characterization is valid for ellipsoids in irrotational linear flow, and it gives good results for spheres in general linear flows at low capillary numbers. We demonstrate that deformable non-spherical particles align with the principal axes of an imposed irrotational flow. Thus, it is most practical to model deformation of non-spherical particles already aligned with the flow, rather than considering each arbitrary orientation. Capsule deformation was modeled for a sphere, a prolate spheroid, and an oblate spheroid, subjected to combinations of uniaxial, biaxial, and planar extensional flows; modeling was performed using the immersed boundary method. The time response of each capsule to each flow was found, as were the steady-state deformation factor, mean strain energy, and surface area. For a given capillary number, planar flows led to more deformation than uniaxial or biaxial extensional flows. Capsule behavior in all cases was bounded by the response of capsules to uniaxial, biaxial, and planar extensional flow. PMID:23426110

  17. In vitro study on sustained release capsule formulation of acetazolamide.

    PubMed

    Pandey, V P; Kannan, K; Manavalan, R; Desai, N

    2003-10-01

    In the present study formulation of sustained release capsule of acetazolamide 250 mg was tried using nonpareil seeds. Nonpareil seeds were coated with drug, polyvinylpyrrolidone, glyceryl monostearate, microcrystalline wax, and glyceryl distearate either individually or in combination to achieve sustained release capsule 250 mg. In successful formulation 20% drug coated pellets and 80% wax coated pellets were taken. Wax coated pellets for successful formulation contained coating of microcrystalline wax and glyceryl distearate on drug coated pellets of the same concentration of 1.6% w/w. Successful formulated sustained release capsule 250 mg of acetazolamide was compared in in vitro study with theoretical sustained release formulation suggested by wagner and one marketed sustained release capsule 250 mg. Formulated capsule showed result superior to or on par with marketed capsule. For successful formulation pellets were filled in '1' size hard gelatin capsule and stability study was carried out in hot air over at room temperature and 45 degrees C for 5 weeks. The formulation was found stable in respect of drug content and release rate.

  18. Direct Drive Beryllium Ablator Capsules for the Omega Laser

    NASA Astrophysics Data System (ADS)

    Bradley, P. A.; Wilson, D. C.; Cobble, J. A.; Murphy, T. J.; Cooley, J. C.; Salazar, M. A.; Rivera Nobile, G., Jr.

    2001-10-01

    We are designing direct drive beryllium ablator capsules for the Omega laser as part of our effort to develop beryllium ablator ignition capsules for the National Ignition Facility (NIF). The main goals for this experimental campaign is to develop the fabrication expertise for roughly NIF size capsules and obtain experimental data on how the copper- brazed joint between the beryllium hemispheres affects the implosion. Our proposed design calls for an 1180 micron outisde diameter capsule with 40 micron thick beryllium walls containing 50 atm of deuterium gas. Some of the capsules will also have 0.05 atm of argon. We plan to image the joints with argon fluorescence from inside the capsule. Our plan is to use a 1 ns square pulse with 30 kJ of laser energy. With this drive, we expect the convergence ratio to be about 6.5 to 7. Depending on the capsule design details, we expect that the peak temperature will be 490 ± 40 eV, and the neutron yield will be anywhere from 1× 10^8 to 8× 10^8 neutrons. Some of the uncertainty comes from whether or not we use argon and questions about how much mix the copper-brazed joint will cause. The yield also depends strongly on which beryllium alloy we use. We calculate better implosions in direct drive with pure beryllium, but requirements on allowable grain size may force us to use copper-doped beryllium, which would reduce the yield by about 50%.

  19. Reduced Compression and Yield for Direct Drive ICF Capsules

    NASA Astrophysics Data System (ADS)

    Kyrala, George; Benage, John; Dodd, Evan; Wilson, Douglas

    2010-11-01

    We report on a series of experiments conducted at the LLE's Omega Laser to study the effect of high z dopant gases on the performance of D2 filled capsules. The experiments all consisted of thin, ˜ 4.5 microns, glass capsules filled with 7-10 atm. of gas that were imploded using the direct drive laser beams at Omega. The laser conditions for these experiments were 1 ns flat pulses with a total energy of ˜ 23 kJ. The typical implosion times were ˜ 1.3 ns and yields ranged from 10^9 neutrons to > 10^11 neutrons. The capsules were doped with varying levels of Kr gas and also in several cases contained He3. A key finding of these experiments was that the capsules did not reach the full compression predicted by simulation. Specifically, we found that the capsule diameter matched the simulation until the time when the main reflected shock reached the shell. After that time, the capsule diameter is measured to be larger than predicted. In this presentation, we quantify the effect of this reduced compression on the yield of the capsule.

  20. Polysaccharide Nanosystems for Future Progress in Cardiovascular Pathologies

    PubMed Central

    Silva, Amanda Karine Andriola; Letourneur, Didier; Chauvierre, Cédric

    2014-01-01

    Natural polysaccharides have received a lot of attention in the biomedical field. Indeed, sources of polysaccharides, extracted or produced from plants, bacteria, fungi or algae, are diverse and renewable. Moreover, recent progresses in polysaccharide chemistry and nanotechnologies allow elaborating new dedicated nanosystems. Polysaccharide-based nanosystems may be designed for interacting in several biological processes. In particular, the atherothrombotic pathology is highly concerned by polysaccharide-mediated recognition. Atherothrombotic diseases, regardless of the anatomical localization, remain the main causes of morbidity and mortality in the industrialized world. This review intends to provide an overview on polysaccharide-based nanosystems as drug delivery systems and targeted contrast agents for molecular imaging with an emphasis on the treatment and imaging of cardiovascular pathologies. PMID:24723980

  1. Iron oxyhydroxide mineralization on microbial extracellular polysaccharides

    NASA Astrophysics Data System (ADS)

    Chan, Clara S.; Fakra, Sirine C.; Edwards, David C.; Emerson, David; Banfield, Jillian F.

    2009-07-01

    Iron biominerals can form in neutral pH microaerophilic environments where microbes both catalyze iron oxidation and create polymers that localize mineral precipitation. In order to classify the microbial polymers that influence FeOOH mineralogy, we studied the organic and mineral components of biominerals using scanning transmission X-ray microscopy (STXM), micro X-ray fluorescence (μXRF) microscopy, and high-resolution transmission electron microscopy (HRTEM). We focused on iron microbial mat samples from a creek and abandoned mine; these samples are dominated by iron oxyhydroxide-coated structures with sheath, stalk, and filament morphologies. In addition, we characterized the mineralized products of an iron-oxidizing, stalk-forming bacterial culture isolated from the mine. In both natural and cultured samples, microbial polymers were found to be acidic polysaccharides with carboxyl functional groups, strongly spatially correlated with iron oxyhydroxide distribution patterns. Organic fibrils collect FeOOH and control its recrystallization, in some cases resulting in oriented crystals with high aspect ratios. The impact of polymers is particularly pronounced as the materials age. Synthesis experiments designed to mimic the biomineralization processes show that the polysaccharide carboxyl groups bind dissolved iron strongly but release it as mineralization proceeds. Our results suggest that carboxyl groups of acidic polysaccharides are produced by different microorganisms to create a wide range of iron oxyhydroxide biomineral structures. The intimate and potentially long-term association controls the crystal growth, phase, and reactivity of iron oxyhydroxide nanoparticles in natural systems.

  2. Nanofiltration of polysaccharides from Agaricus subrufescens.

    PubMed

    Camelini, C M; Rezzadori, K; Benedetti, S; Proner, M C; Fogaça, L; Azambuja, A A; Giachini, A J; Rossi, M J; Petrus, J C C

    2013-12-01

    A simplified submerged airlift cultivation was established for the production of biomass from Agaricus subrufescens. In this work, soluble polysaccharides extracted from fungal mycelium, fruiting bodies, and the residual culture media were concentrated by nanofiltration. Total and high molar mass polysaccharides and soluble solids were determined in the concentrate for the three extracts. Additionally, the permeate flow, the influences of temperature and pressure, and the resistance to the permeate flow during filtration were also evaluated. Ayield of 5.5 g/L of biomass with 35%glucose conversion was obtained when 0.5 g/L of initial inoculum was employed. Average specific speed of growth was 0.4/day, with biomass productivity of about 0.76 g/(L day). Nanofiltration has yielded polysaccharide increases of 85, 82, and 92% in the extracts from fruiting bodies, mycelium, and liquid media, respectively. A reduction in the permeate flow was observed during filtration, and it was compensated by higher pressures and temperatures. The higher resistance to the permeate flux was caused by polarization due to concentration (polarized gel layer), reaching values of 88% for the culture media. Maximal resistance caused by the membrane reached values of 40% for the extract from the fruiting bodies. On the other hand, resistance caused by fouling was responsible for less than 3.5%. In conclusion, nanofiltration is efficient to concentrate these functional compounds extracted from A. subrufescens and can, therefore, be applied in different biotechnological areas.

  3. Iron oxyhydroxide mineralization on microbial extracellular polysaccharides

    SciTech Connect

    Chan, Clara S.; Fakra, Sirine C.; Edwards, David C.; Emerson, David; Banfield, Jillian F.

    2010-06-22

    Iron biominerals can form in neutral pH microaerophilic environments where microbes both catalyze iron oxidation and create polymers that localize mineral precipitation. In order to classify the microbial polymers that influence FeOOH mineralogy, we studied the organic and mineral components of biominerals using scanning transmission X-ray microscopy (STXM), micro X-ray fluorescence ({mu}XRF) microscopy, and high-resolution transmission electron microscopy (HRTEM). We focused on iron microbial mat samples from a creek and abandoned mine; these samples are dominated by iron oxyhydroxide-coated structures with sheath, stalk, and filament morphologies. In addition, we characterized the mineralized products of an iron-oxidizing, stalk-forming bacterial culture isolated from the mine. In both natural and cultured samples, microbial polymers were found to be acidic polysaccharides with carboxyl functional groups, strongly spatially correlated with iron oxyhydroxide distribution patterns. Organic fibrils collect FeOOH and control its recrystallization, in some cases resulting in oriented crystals with high aspect ratios. The impact of polymers is particularly pronounced as the materials age. Synthesis experiments designed to mimic the biomineralization processes show that the polysaccharide carboxyl groups bind dissolved iron strongly but release it as mineralization proceeds. Our results suggest that carboxyl groups of acidic polysaccharides are produced by different microorganisms to create a wide range of iron oxyhydroxide biomineral structures. The intimate and potentially long-term association controls the crystal growth, phase, and reactivity of iron oxyhydroxide nanoparticles in natural systems.

  4. Immunoregulatory activities of polysaccharides from mung bean.

    PubMed

    Yao, Yang; Zhu, Yingying; Ren, Guixing

    2016-03-30

    Ultrasonic treatment was performed on water-extractable polysaccharides from the seed of mung beans. Purified by anion-exchange and gel filtration chromatography, MWP-1' and MWP-2' were obtained. Average molecular weights (Mws) of MWP-1' and MWP-2' were 68.4 kDa, and 52.4 kDa, respectively. Monosaccharides components analysis indicated that MWP-1' was composed of Rha, Ara, Man and Gal in a molar percent of 0.4:2.6:5.3:0.7. MWP-2' was composed of Ara, Man, Gal and Glc in a molar percent of 0.5:1.4:2.1:0.4. In vitro study showed that both polysaccharides samples were able to stimulate the production of secretory molecules (NO, TNF-α and IL-6) of RAW264.7 murine macrophages in a dosage dependent manner. MWP-2' seemed to be the most potent and induced significantly higher the NO production. These findings suggest that the ultrasonic treatment polysaccharides isolated in our study have immune potentiation effects on macrophages.

  5. Immunochemical characterization of Brucella lipopolysaccharides and polysaccharides.

    PubMed Central

    Moreno, E; Speth, S L; Jones, L M; Berman, D T

    1981-01-01

    Purified lipopolysaccharide (LPS) extracted with phenol-water from smooth Brucella abortus was hydrolyzed with 1% acetic acid at 100 degrees C. The degraded polysaccharide (AH) released gave reactions of identity with the native polysaccharide hapten (NH) in phenol-water- or trichloroacetic acid-extracted endotoxin preparations of B. abortus and with the polysaccharide (poly B) extracted by trichloroacetic acid from rough B. melitensis strain B115. Poly B was present in the soluble cytoplasmic fraction but not in the membrane fraction, of disrupted B115 cells. It could not be extracted from three rough mutants of B. abortus or from B canis or B. ovis cells. Both AH and NH shared determinants present on smooth LPS and missing from poly B. Sugars found in purified LPS, NH, and AH included mannose, glucose, quinovosamine, glucosamine, and 2-keto-3-deoxyoctonate. Poly B contained only a trace amount of quinovosamine and no 2-keto-3-deoxyoctonate detectable by the thiobarbiturate assay. Sera from some rabbits immunized with pure smooth LPS and some, but not all, cows infected with field strains of B. abortus recognized the determinants missing from poly B. A subclass-specific enzyme-linked immunoassay showed that most of the antibody in sera from infected cows which binds to smooth LPS and to NH is of the immunoglobulin G1 subclass. Images PMID:6163716

  6. Solid State Stability of Extemporaneously Prepared Levothyroxine Aliquots and Capsules.

    PubMed

    Fortner, Jeff; Salton, Jason; Carlson, Christie; Wheeler, Rich; Cote, Brianna; Rao, Deepa

    2015-01-01

    The purpose of this research was to collect, analyze, and compare stability data for levothyroxine (T4) powder in the anhydrous and pentahydrate form when prepared as an aliquot and in capsules. Two different compounding pharmacies, Central Iowa Compounding and Gateway Medical Pharmacy, used different forms of T4 and aliquot formulations, which were studied to determine the beyond-use date at ±5% or ±10% of labeled strength. T4 was extracted from aliquot and capsule formulations and assessed using reverse-phase high- performance liquid chromatography validated to differentiate between the degraded and original forms of T4. The results indicate that T4 1:100 aliquot formulation prepared with silica gel or Avicel as filler are stable for 120 days at ±10% labeled potency, but at ±5% labeled potency, the silica gel and Avicel aliquot formulations are stable for 45 and 30 days, respectively. The silica gel capsules prepared from fresh aliquot were stable for 120 days at ±10% labeled potency and 90 days at ±5% labeled potency, while the Avicel capsules prepared from fresh aliquot were stable for 180 days at both ±10% and ±5% labeled potency. Avicel capsules prepared from old aliquot (120 days) and fresh aliquot (1 day) were also compared for stability. The old aliquot Avicel capsules were stable for 14 days at ±5% labeled potency and 150 days at ±10% labeled potency, while new aliquot Avicel capsules were stable for 180 days at both ±10% and ±5% labeled potency. Based on our data, there can be significant variation in the beyond-use dates assigned to T4 capsules based on the diluents used for aliquots, the final capsule formulations, and the potency standards applied. These results also indicate that pharmacists must exercise caution when using older aliquots and may have to assign shorter beyond-use dates.

  7. Evaluation of Phosphorylated Psyllium Seed Polysaccharide as a Release Retardant.

    PubMed

    Rao, Monica R P; Warrier, Deepa U; Rao, Shivani H

    2015-01-01

    The aim of the present study was to modify psyllium seed polysaccharide and evaluate the modified polysaccharide as release retardant in tablets employing ciprofloxacin hydrochloride as model drug. Studies on polysaccharide from psyllium husk has been reported but no work has been reported on characterization and modification of the polysaccharide present in the psyllium (Plantago ovata) seed and the use of the modified polysaccharide as a release retardant in tablets. In this study, the seed gum was modified using sodium trimetaphosphate as crosslinking agent. Sustained release matrix tablets of ciprofloxacin hydrochloride were prepared by wet granulation using various drug-polymer ratios. The polymers investigated were psyllium polysaccharide, phosphorylated psyllium polysaccharide and widely used release retardant hydroxypropyl methylcellulose K100M. The tablets were evaluated for hardness, friability, drug content, swelling profile and in vitro dissolution studies. The matrix tablets containing 1:3 proportion of drug-phosphorylated psyllium polysaccharide was found to have higher hardness as compared to tablets containing 1:1 and 1:2 proportions. The results of swelling behavior in water showed that the tablets containing 1:3 drug:phosphorylated psyllium polysaccharide ratio had swelling comparable to that of tablets containing 1:3 drug:hydroxypropyl methylcellulose ratio. The in vitro dissolution studies shows that the dissolution rate was retarded from 98.41 to 37.6% in 6 h with increase in concentration of phosphorylated psyllium polysaccharide from 100 to 300 mg. Formulations containing psyllium polysaccharide showed complete drug release in 8 h whereas those formulated with phosphorylated psyllium polysaccharide exhibited extended drug release over the 12 h period. Drug release kinetic studies revealed that drug release followed Korsmeyer-Peppas model. PMID:26798177

  8. Evaluation of Phosphorylated Psyllium Seed Polysaccharide as a Release Retardant

    PubMed Central

    Rao, Monica R. P.; Warrier, Deepa U.; Rao, Shivani H.

    2015-01-01

    The aim of the present study was to modify psyllium seed polysaccharide and evaluate the modified polysaccharide as release retardant in tablets employing ciprofloxacin hydrochloride as model drug. Studies on polysaccharide from psyllium husk has been reported but no work has been reported on characterization and modification of the polysaccharide present in the psyllium (Plantago ovata) seed and the use of the modified polysaccharide as a release retardant in tablets. In this study, the seed gum was modified using sodium trimetaphosphate as crosslinking agent. Sustained release matrix tablets of ciprofloxacin hydrochloride were prepared by wet granulation using various drug-polymer ratios. The polymers investigated were psyllium polysaccharide, phosphorylated psyllium polysaccharide and widely used release retardant hydroxypropyl methylcellulose K100M. The tablets were evaluated for hardness, friability, drug content, swelling profile and in vitro dissolution studies. The matrix tablets containing 1:3 proportion of drug-phosphorylated psyllium polysaccharide was found to have higher hardness as compared to tablets containing 1:1 and 1:2 proportions. The results of swelling behavior in water showed that the tablets containing 1:3 drug:phosphorylated psyllium polysaccharide ratio had swelling comparable to that of tablets containing 1:3 drug:hydroxypropyl methylcellulose ratio. The in vitro dissolution studies shows that the dissolution rate was retarded from 98.41 to 37.6% in 6 h with increase in concentration of phosphorylated psyllium polysaccharide from 100 to 300 mg. Formulations containing psyllium polysaccharide showed complete drug release in 8 h whereas those formulated with phosphorylated psyllium polysaccharide exhibited extended drug release over the 12 h period. Drug release kinetic studies revealed that drug release followed Korsmeyer-Peppas model. PMID:26798177

  9. [Video capsule endoscopy in the diagnostics of small intestine diseases].

    PubMed

    Nakatis, Ia A; Borisov, A E; Kashchenko, V A; Sishkova, E A; Raspereza, D V; Lobach, S M; Tiniakova, T V; Pavlov, A V

    2008-01-01

    Video capsule endoscopy is a safe and noninvasive, well-endurable method of the direct visual inspection of the whole of the small intestine. The most frequent indications for video capsule endoscopy are the diagnostics of latent gastro-intestinal bleedings, angiodysplasias, Crohn disease, celiac disease, syndromes of hereditary polyposis and tumors of the small intestine. The authors describe the first experience of using this new method in the domestic clinical practice. Data concerning the diagnostics of lesions of the small intestine by the method of video capsule endoscopy as well as the wide range of lesions of the mucous membrane in different diseases of the small intestine are presented.

  10. Subphthalocyanines hydrogen bonded capsules featuring norbornadiene tethers: Promising fullerene receptors

    NASA Astrophysics Data System (ADS)

    Denis, Pablo A.; Yanney, Michael

    2015-11-01

    We have employed density functional theory to study new subphthalocyanine based receptors which feature the 1,4-dithiino and norbornadiene linkages. The latter linkage significantly improves the host binding capabilities with respect to subphthalocyanine based receptors. Moreover, the interaction energy of the new subphthalocyanine-norbornadiene receptor is larger than that computed for the C60H28 buckycatcher. The dimerization of the new receptor forms a hydrogen-bonded capsule. Through a combination of non-bonded interactions, this capsule can bind C60 with an unprecedented affinity. Due to the exceptional stability of this capsule, it is our hope that it can be used for other guests besides fullerenes.

  11. Characterisation of two AGATA asymmetric high purity germanium capsules

    NASA Astrophysics Data System (ADS)

    Colosimo, S. J.; Moon, S.; Boston, A. J.; Boston, H. C.; Cresswell, J. R.; Harkness-Brennan, L.; Judson, D. S.; Lazarus, I. H.; Nolan, P. J.; Simpson, J.; Unsworth, C.

    2015-02-01

    The AGATA spectrometer is an array of highly segmented high purity germanium detectors. The spectrometer uses pulse shape analysis in order to track Compton scattered γ-rays to increase the efficiency of nuclear spectroscopy studies. The characterisation of two high purity germanium detector capsules for AGATA of the same A-type has been performed at the University of Liverpool. This work will examine the uniformity of performance of the two capsules, including a comparison of the resolution and efficiency as well as a study of charge collection. The performance of the capsules shows good agreement, which is essential for the efficient operation of the γ-ray tracking array.

  12. Role of anaerobiosis in capsule production and biofilm formation in Vibrio vulnificus.

    PubMed

    Phippen, Britney L; Oliver, James D

    2015-02-01

    Vibrio vulnificus, a pervasive human pathogen, can cause potentially fatal septicemia after consumption of undercooked seafood. Biotype 1 strains of V. vulnificus are most commonly associated with human infection and are separated into two genotypes, clinical (C) and environmental (E), based on the virulence-correlated gene. For ingestion-based vibriosis to occur, this bacterium must be able to withstand multiple conditions as it traverses the gastrointestinal tract and ultimately gains entry into the bloodstream. One such condition, anoxia, has yet to be extensively researched in V. vulnificus. We investigated the effect of oxygen availability on capsular polysaccharide (CPS) production and biofilm formation in this bacterium, both of which are thought to be important for disease progression. We found that lack of oxygen elicits a reduction in both CPS and biofilm formation in both genotypes. This is further supported by the finding that pilA, pilD, and mshA genes, all of which encode type IV pilin proteins that aid in attachment to surfaces, were downregulated during anaerobiosis. Surprisingly, E-genotypes exhibited distinct differences in gene expression levels of capsule and attachment genes compared to C-genotypes, both aerobically and anaerobically. The importance of understanding these disparities may give insight into the observed differences in environmental occurrence and virulence potential between these two genotypes of V. vulnificus.

  13. Effect of thorium on the growth and capsule morphology of Bradyrhizobium.

    PubMed

    Santamaría, Mónica; Díaz-Marrero, Ana R; Hernández, Jairo; Gutiérrez-Navarro, Angel M; Corzo, Javier

    2003-10-01

    The thorium effect on Bradyrhizobium growth was assayed in liquid media. Th4+ inhibited the growth of Bradyrhizobium (Chamaecytisus) BGA-1, but this effect decreased in the presence of suspensions of live or dead bacterial cells. Th4+ induced the formation of a gel-like precipitate when added to a dense suspension of B. (Chamaecytisus) BGA-1 cells. Viable Bradyrhizobium cells remained in suspension after precipitate formation. Thorium was recovered in the precipitate, in which polysaccharide, lipopolysaccharide and proteins were also found. After Th4+ addition, the morphology of B. (Chamaecytisus) BGA-1 or Bradyrhizobium japonicum USDA 110 sedimented cells studied by scanning electron microscopy changed from an entangled network of capsulated bacteria to uncapsulated individual cells and an amorphous precipitate. Energy-dispersive X-ray spectroscopy showed that thorium was mainly in the amorphous fraction. Precipitate was also formed between B. (Chamaecytisus) BGA-1 and Al3+, which was also toxic to this bacterium. Precipitate induced by Th4+ or Al3+ was found in all Bradyrhizobium and Sinorhizobium strains tested, but not in Rhizobium, Salmonella typhimurium, Aerobacter aerogenes or Escherichia coli. These results suggest a specific defence mechanism based on metal precipitation by extracellular polymers.

  14. Role of Anaerobiosis in Capsule Production and Biofilm Formation in Vibrio vulnificus

    PubMed Central

    Phippen, Britney L.

    2014-01-01

    Vibrio vulnificus, a pervasive human pathogen, can cause potentially fatal septicemia after consumption of undercooked seafood. Biotype 1 strains of V. vulnificus are most commonly associated with human infection and are separated into two genotypes, clinical (C) and environmental (E), based on the virulence-correlated gene. For ingestion-based vibriosis to occur, this bacterium must be able to withstand multiple conditions as it traverses the gastrointestinal tract and ultimately gains entry into the bloodstream. One such condition, anoxia, has yet to be extensively researched in V. vulnificus. We investigated the effect of oxygen availability on capsular polysaccharide (CPS) production and biofilm formation in this bacterium, both of which are thought to be important for disease progression. We found that lack of oxygen elicits a reduction in both CPS and biofilm formation in both genotypes. This is further supported by the finding that pilA, pilD, and mshA genes, all of which encode type IV pilin proteins that aid in attachment to surfaces, were downregulated during anaerobiosis. Surprisingly, E-genotypes exhibited distinct differences in gene expression levels of capsule and attachment genes compared to C-genotypes, both aerobically and anaerobically. The importance of understanding these disparities may give insight into the observed differences in environmental occurrence and virulence potential between these two genotypes of V. vulnificus. PMID:25404024

  15. Autophosphorylation of the Bacterial Tyrosine-Kinase CpsD Connects Capsule Synthesis with the Cell Cycle in Streptococcus pneumoniae.

    PubMed

    Nourikyan, Julien; Kjos, Morten; Mercy, Chryslène; Cluzel, Caroline; Morlot, Cécile; Noirot-Gros, Marie-Francoise; Guiral, Sébastien; Lavergne, Jean-Pierre; Veening, Jan-Willem; Grangeasse, Christophe

    2015-09-01

    Bacterial capsular polysaccharides (CPS) are produced by a multi-protein membrane complex, in which a particular type of tyrosine-autokinases named BY-kinases, regulate their polymerization and export. However, our understanding of the role of BY-kinases in these processes remains incomplete. In the human pathogen Streptococcus pneumoniae, the BY-kinase CpsD localizes at the division site and participates in the proper assembly of the capsule. In this study, we show that the cytoplasmic C-terminal end of the transmembrane protein CpsC is required for CpsD autophosphorylation and localization at mid-cell. Importantly, we demonstrate that the CpsC/CpsD complex captures the polysaccharide polymerase CpsH at the division site. Together with the finding that capsule is not produced at the division site in cpsD and cpsC mutants, these data show that CPS production occurs exclusively at mid-cell and is tightly dependent on CpsD interaction with CpsC. Next, we have analyzed the impact of CpsD phosphorylation on CPS production. We show that dephosphorylation of CpsD induces defective capsule production at the septum together with aberrant cell elongation and nucleoid defects. We observe that the cell division protein FtsZ assembles and localizes properly although cell constriction is impaired. DAPI staining together with localization of the histone-like protein HlpA further show that chromosome replication and/or segregation is defective suggesting that CpsD autophosphorylation interferes with these processes thus resulting in cell constriction defects and cell elongation. We show that CpsD shares structural homology with ParA-like ATPases and that it interacts with the chromosome partitioning protein ParB. Total internal reflection fluorescence microscopy imaging demonstrates that CpsD phosphorylation modulates the mobility of ParB. These data support a model in which phosphorylation of CpsD acts as a signaling system coordinating CPS synthesis with chromosome segregation

  16. Vulnerability of ecosystems to climate change moderated by habitat intactness.

    PubMed

    Eigenbrod, Felix; Gonzalez, Patrick; Dash, Jadunandan; Steyl, Ilse

    2015-01-01

    The combined effects of climate change and habitat loss represent a major threat to species and ecosystems around the world. Here, we analyse the vulnerability of ecosystems to climate change based on current levels of habitat intactness and vulnerability to biome shifts, using multiple measures of habitat intactness at two spatial scales. We show that the global extent of refugia depends highly on the definition of habitat intactness and spatial scale of the analysis of intactness. Globally, 28% of terrestrial vegetated area can be considered refugia if all natural vegetated land cover is considered. This, however, drops to 17% if only areas that are at least 50% wilderness at a scale of 48×48 km are considered and to 10% if only areas that are at least 50% wilderness at a scale of 4.8×4.8 km are considered. Our results suggest that, in regions where relatively large, intact wilderness areas remain (e.g. Africa, Australia, boreal regions, South America), conservation of the remaining large-scale refugia is the priority. In human-dominated landscapes, (e.g. most of Europe, much of North America and Southeast Asia), focusing on finer scale refugia is a priority because large-scale wilderness refugia simply no longer exist. Action to conserve such refugia is particularly urgent since only 1 to 2% of global terrestrial vegetated area is classified as refugia and at least 50% covered by the global protected area network.

  17. Vulnerability of ecosystems to climate change moderated by habitat intactness.

    PubMed

    Eigenbrod, Felix; Gonzalez, Patrick; Dash, Jadunandan; Steyl, Ilse

    2015-01-01

    The combined effects of climate change and habitat loss represent a major threat to species and ecosystems around the world. Here, we analyse the vulnerability of ecosystems to climate change based on current levels of habitat intactness and vulnerability to biome shifts, using multiple measures of habitat intactness at two spatial scales. We show that the global extent of refugia depends highly on the definition of habitat intactness and spatial scale of the analysis of intactness. Globally, 28% of terrestrial vegetated area can be considered refugia if all natural vegetated land cover is considered. This, however, drops to 17% if only areas that are at least 50% wilderness at a scale of 48×48 km are considered and to 10% if only areas that are at least 50% wilderness at a scale of 4.8×4.8 km are considered. Our results suggest that, in regions where relatively large, intact wilderness areas remain (e.g. Africa, Australia, boreal regions, South America), conservation of the remaining large-scale refugia is the priority. In human-dominated landscapes, (e.g. most of Europe, much of North America and Southeast Asia), focusing on finer scale refugia is a priority because large-scale wilderness refugia simply no longer exist. Action to conserve such refugia is particularly urgent since only 1 to 2% of global terrestrial vegetated area is classified as refugia and at least 50% covered by the global protected area network. PMID:25059822

  18. Antibacterial and antiviral study of dialdehyde polysaccharides

    NASA Astrophysics Data System (ADS)

    Song, Le

    Concerns for microbial contamination and infection to the general population, especially the spread of drug-resistant microorganisms, have greatly increased. Polymeric biocides have been found to be a feasible strategy to inactivate drug-resistant bacteria. However, current polymeric biocide systems involve multi-step chemical reactions and they are not cost-effective. Desirable antimicrobial systems need to be designed to be environmentally friendly, broad-spectrum effective against microorganisms, flexible for various delivery methods and economically affordable. We demonstrated that dialdehyde polysaccharides (including dialdehyde starch and dialdehdye cellulose) were broad-spectrum polymeric biocides against gram-positive/negative bacteria, bacteriophages and human virus. These polymers can be easily converted from starch and cellulose through one-step periodate oxidation. Destructions of microorganism by dialdehyde polysaccharides have been achieved in aqueous suspension or by solid surface contact. The dialdehdye functions of dialdehdye polysaccharides were found to be the dominant action against microorganism. The reactivity of the dialdehyde functionality was found to be pH-dependent as well as related to the dispersion of dialdehyde polysaccharides. Degradation of dialdehyde starch during cooking was confirmed. Degradation of dialdehyde starch was more liable in alkaline condition. Carboxylic acid and conjugated aldehyde functionalities were the two main degradation products, confirmed from the spectroscopic studies. The pH effect on the polysaccharide structure and the corresponding antimicrobial activity was very complicated. No decisive conclusions could be obtained from this study. Liner inactivation kinetics was found for dialdehyde starch aqueous suspension against bacteria. This linear inactivation kinetics was derived from the pseudo-first chemical reaction between the dialdehyde starch and the bacteria. The established inactivation kinetics was

  19. Fungal Polysaccharides: Biological Activity Beyond the Usual Structural Properties

    PubMed Central

    Rodrigues, Marcio L.; Nimrichter, Leonardo; Cordero, Radames J. B.; Casadevall, Arturo

    2011-01-01

    Studies on structure and function of polysaccharides in biological systems classically involve sequence and compositional analyses, anomeric configuration, type of glycosidic linkage, and presence of substituents. Recent studies, however, indicates that other structural parameters, so far little explored, can directly influence the biological activity of microbial polysaccharides. Among these parameters, we highlight the molecular dimensions of Cryptococcus neoformans polysaccharides, which appear to be inversely correlated with their immunobiological activity. These recent observations raise new concepts about the structure and function of polysaccharides, which stimulates the design of new experimental approaches and suggests previously unknown applications. PMID:21886639

  20. Polysaccharide based Copolymers as Supramolecular Systems in Biomedical Applications.

    PubMed

    Célia Monteiro de Paula, Regina; Andrade Feitosa, Judith Pessoa; Beserra Paula, Haroldo César

    2015-01-01

    Polysaccharides are natural polymers, obtained from a large variety of sources ranging from fungi to more complex organisms such as birds and whales. Their use for pharmaceutical and biomedical applications has been the subject of numerous researches by the world´s academia. Polysaccharide chemical/physical modifications leading to graft copolymers are discussed in this review, focusing on those nanosystems that are potential candidates for drug delivery applications. Therefore, this review focuses on the biomedical application of polysaccharide based copolymers, particularly as nanocarriers. Copolymer of polysaccharides such as alginate, cellulose, chitosan, dextran, guar, hyaluronic acid, pullulan and starch as drug delivery nanocarriers will be discussed. PMID:26424388