scholarly journals Polymorphisms in Pilin Glycosylation Locus of Neisseria meningitidis Expressing Class II Pili

2001 ◽  
Vol 69 (6) ◽  
pp. 3597-3604 ◽  
Author(s):  
Charlene M. Kahler ◽  
Larry E. Martin ◽  
Yih-Ling Tzeng ◽  
Yoon K. Miller ◽  
Kerith Sharkey ◽  
...  
Keyword(s):  
Neisseria Meningitidis ◽  
Human Serum ◽  
Class Ii ◽  
Open Reading Frames ◽  
Normal Human Serum ◽  
Wild Type ◽  
Experimental Conditions ◽  
Type Iv ◽  
Insertional Inactivation ◽  
Normal Human

ABSTRACT We have located a locus, pgl, in Neisseria meningitidis strain NMB required for the glycosylation of class II pili. Between five and eight open reading frames (ORFs) (pglF, pglB, pglC, pglB2, orf2, orf3, orf8, and avtA) were present in the pgl clusters of different meningococcal isolates. The Class I pilus-expressing strains Neisseria gonorrhoeae MS11 and N. meningitidis MC58 each contain a pgl cluster in which orf2 andorf3 have been deleted. Strain NMB and other meningococcal isolates which express class II type IV pili contained pglclusters in which pglB had been replaced bypglB2 and an additional novel ORF, orf8, had been inserted between pglB2 and pglC. Insertional inactivation of the eight ORFs of the pglcluster of strain NMB showed that pglF, pglB2, pglC, andpglD, but not orf2, orf3, orf8, andavtA, were necessary for pilin glycosylation. Pilin glycosylation was not essential for resistance to normal human serum, as pglF and pglD mutants retained wild-type levels of serum resistance. Although pglB2 andpglC mutants were significantly sensitive to normal human serum under the experimental conditions used, subsequent examination of the encapsulation phenotypes revealed that pglB2 andpglC mutants expressed almost 50% less capsule than wild-type NMB. A mutation in orf3, which did not affect pilin glycosylation, also resulted in a 10% reduction in capsule expression and a moderately serum sensitive phenotype. On the basis of these results we suggest that pilin glycosylation may proceed via a lipid-linked oligosaccharide intermediate and that blockages in this pathway may interfere with capsular transport or assembly.

scholarly journals Influence of the Length of the Lipooligosaccharide α Chain on Its Sialylation in Neisseria meningitidis

2002 ◽  
Vol 70 (1) ◽  
pp. 407-411 ◽  
Author(s):  
Chao-Ming Tsai ◽  
George Kao ◽  
Peixuan Zhu
Keyword(s):  
Neisseria Meningitidis ◽  
Human Serum ◽  
Steric Hindrance ◽  
Normal Human Serum ◽  
Normal Human ◽  
Α Chain

ABSTRACT The sialylation of lipooligosaccharide (LOS) in Neisseria meningitidis plays a role in the resistance of the organism to killing by normal human serum. The length of the α chain extending out from the heptose I [Hep (I)] moiety of LOS influenced sialylation of N. meningitidis LOS in vitro and in vivo. The α chain required a terminal Gal and a trisaccharide or longer oligosaccharide to serve as an acceptor for sialylation. The disaccharide lactose (Galβ1-4Glc) in the α chain of immunotype L8 LOS could not function as an acceptor for the sialyltransferase, probably due to steric hindrance imposed by the neighboring Hep (II) with phosphorylethanolamine and another group attached.

scholarly journals INTERRELATIONSHIP BETWEEN THE Rh SYSTEM AND THE A B SYSTEM

Blood ◽  
1948 ◽  
Vol 3 (Special_Issue_Number_2) ◽  
pp. 66-79 ◽  
Author(s):  
ERNEST WITEBSKY ◽  
MRS. LIVIA BLUM ◽  
MISS DORIS HOWLES ◽  
MISS HELEN WARD
Keyword(s):  
Human Serum ◽  
Blood Group ◽  
Saline Solution ◽  
High Titer ◽  
Water Soluble ◽  
Normal Human Serum ◽  
Experimental Conditions ◽  
Blocking Antibody ◽  
Group A ◽  
Normal Human

Abstract The isoantibodies anti-A and anti-B which are described differ in several respects from those occurring in normal human serum. This type of antibody has first been observed in the serum of an Rh negative woman who exhibited a history of erythroblastosis. Her husband belonged to the subtype Rh1 and to the blood group A. The patient’s serum completely neutralized with A and B substances still agglutinated strongly the husband’s cells provided normal human serum replaced physiological saline solution as a diluent for all dilutions. The impression was thus created that an Rh blocking antibody was responsible for the agglutination observed. It could be shown, however, that the abnormal antibody present in this patient’s serum was not an Rh antibody at all but instead, an antibody directed against the A property. This type of anti-A antibody resembles the Rh blocking antibody in many respects. It becomes manifest only if undiluted human serum is used as a diluent. Surprisingly enough this antibody agglutinated cells of group A, although the amount of AB substances added to the serum was sufficient to neutralize completely the isoagglutinin anti-A under normal conditions in which saline solution is used as a diluent. This anti-A antibody therefore cannot be neutralized as easily as the normal isoagglutinin anti-A. For its neutralization much larger amounts of the blood group specific substances are apparently necessary. The patient’s serum fixed complement when mixed with material containing water soluble A substance, in contrast to the normal isoantibody anti-A which failed to do so. The titer of isoantibodies found in the patient’s serum upon titration in saline solution was not extensively high and, as a matter of fact, was average. It is therefore felt that an extremely high titer is neither a necessary requirement nor proof of isoimmunization toward the A and B factors. Another interesting characteristic of the peculiar anti-A antibody occurring in our patient’s serum was the fact that it was essentially an anti-A1 antibody. The difference in agglutination between A1 and A2 cells respectively becomes manifest if normal serum is used as a diluent instead of saline solution. This difference becomes even more marked after neutralization of the patient’s serum with A and B substances. During the course of Mrs. Bong’s pregnancy the special anti-A antibody described did not increase but rather decreased in strength. However, even after delivery the antibody was demonstrable for at least several weeks although we had no opportunity to examine the patient’s serum further. That one must be very careful in contributing any pathological significance to isoantibodies anti-A or anti-B, even of the type described, is evident from the fact that the patient was delivered of a perfectly normal baby belonging to the blood group O and being Rh negative. Whether the difficulties experienced by the patient in previous pregnancies were due to sensitization toward the Rh factor or to the A factor cannot be decided. Antibodies anti-A and anti-B of the type reported were also found in the sera of patients who had received large amounts of pooled plasma or O blood conditioned with A and B specific substances. Again the anti-A antibody occurring in the serum of these patients was mainly directed against the A1 property. Under the experimental conditions described in this paper, such a serum can be used for the differential diagnosis of the subgroups A1 and A2 and constitutes a sensitive reagent for the recognition of the differences occurring within the A factor. With the aid of such a serum only 10 per cent of A cells were found to belong to subgroup A2, 75 per cent to A1, and 15 per cent were considered to be of the intermediate type. No subgroups were found so far in human cells of group B.

scholarly journals Circumvention of Herd Immunity during an Outbreak of Meningococcal Disease Could Be Correlated to Escape Mutation in theporA Gene of Neisseria meningitidis

2001 ◽  
Vol 69 (3) ◽  
pp. 1971-1973 ◽  
Author(s):  
Muhamed-Kheir Taha ◽  
Edouard Bichier ◽  
Anne Perrocheau ◽  
Jean-Michel Alonso
Keyword(s):  
Neisseria Meningitidis ◽  
Human Serum ◽  
Meningococcal Disease ◽  
Type Strain ◽  
Wild Type Strain ◽  
Herd Immunity ◽  
Bactericidal Effect ◽  
Escape Mutation ◽  
Wild Type ◽  
Normal Human

ABSTRACT Meningococcal strains isolated during an outbreak were shown to belong to the ET-5 complex and to harbor a mutation in the VR2 region of the porA gene. They were less susceptible to the bactericidal effect of normal human serum than was the ET-5 wild-type strain. These results are of concern, as PorA is a potential target in vaccine design.

scholarly journals The Capsular Polysaccharide of Burkholderia pseudomallei Contributes to Survival in Serum by Reducing Complement Factor C3b Deposition

2005 ◽  
Vol 73 (2) ◽  
pp. 1106-1115 ◽  
Author(s):  
Shauna L. Reckseidler-Zenteno ◽  
Rebekah DeVinney ◽  
Donald E. Woods
Keyword(s):  
Human Serum ◽  
Burkholderia Pseudomallei ◽  
Capsular Polysaccharide ◽  
Extracellular Polysaccharide ◽  
Normal Human Serum ◽  
Complement Factor ◽  
Wild Type ◽  
Hamster Model ◽  
Capsule Production ◽  
Normal Human

ABSTRACT Burkholderia pseudomallei produces an extracellular polysaccharide capsule -3)-2-O-acetyl-6-deoxy-β-d-manno-heptopyranose-(1- which has been shown to be an essential virulence determinant. The addition of purified capsule was shown to increase the virulence of a capsule mutant strain in the Syrian hamster model of acute melioidosis. An increase in the number of wild-type B. pseudomallei cells in the blood was seen by 48 h, while the number of capsule mutant cells in the blood declined by 48 h. Capsule expression was shown to be induced in the presence of serum using a lux reporter fusion to the capsule gene wcbB. The addition of purified B. pseudomallei capsule to serum bactericidal assays increased the survival of B. pseudomallei SLR5, a serum-sensitive strain, by 1,000-fold in normal human serum. Capsule production by B. pseudomallei contributed to reduced activation of the complement cascade by reducing the levels of complement factor C3b deposition. An increase in phagocytosis of the capsule mutant compared to the wild type was observed in the presence of normal human serum. These results suggest that the production of this capsule contributes to resistance to phagocytosis by reducing C3b deposition on the surface of the bacterium, thereby contributing to the persistence of bacteria in the blood of the infected host. Continued studies to characterize this capsule are essential for understanding the pathogenesis of B. pseudomallei infections and the development of preventive strategies for treatment of this disease.

Evaluation of a commercially available radioimmunoassay kit for measurement of doxorubicin in plasma.

1982 ◽  
Vol 28 (1) ◽  
pp. 119-121 ◽  
Author(s):  
E Piall ◽  
G W Aherne ◽  
V Marks
Keyword(s):  
Human Serum ◽  
Normal Human Serum ◽  
Nonspecific Effects ◽  
Normal Human ◽  
Doxorubicin Concentration

Abstract We evaluated a commercially available (Diagnostic Biochemistry Inc.) doxorubicin 125I radioimmunoassay kit. This kit gave a high apparent doxorubicin concentration (greater than 12 micrograms/L), which was not linearly related to dilution, for two pools of normal human serum and plasma and also for samples collected from patients before they received the drug. In contrast, a doxorubicin 3H radioimmunoassay developed by us gave a low blank (2 micrograms/L), which was linearly related to dilution, for the same pools and patients' samples. Doxorubicin concentrations in the plasma of patients receiving the drug were compared by the two methods; the kit gave results five- to 10-fold those obtained with our assay. High nonspecific interference by serum and plasma as measured by the 125I radioimmunoassay must therefore be borne in mind by users of the kit, and we suggest that results should be corrected for these nonspecific effects.

The Presence of Two Forms of Insulin in Normal Human Serum

Biochemistry ◽  
1963 ◽  
Vol 2 (2) ◽  
pp. 286-289 ◽  
Author(s):  
Walter N. Shaw ◽  
Eldon W. Shuey
Keyword(s):  
Human Serum ◽  
Normal Human Serum ◽  
Normal Human
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