Neisseria gonorrhoeae that infect men have lipooligosaccharides with terminal N-acetyllactosamine repeats

Infectious Neisseria gonorrhoeae make relatively large lipooligosaccharides (LOS) that structurally resemble human glycosphingolipids. MS11mkC is an LOS variant of N. gonorrhoeae strain MS11 which was isolated from men at the onset of dysuria (Schneider, H., Griffiss, J. M., Boslego, J. W., Hitchcock, P. J., Zahos, K. M., and Apicella, M. A. (1991) J. Exp. Med. 174, 1601-1605). Delayed extraction matrix-assisted laser desorption and ionization and electrospray ionization mass spectrometry of O-deacylated MS11mkC LOS produced ions consistent with known LOS which have lacto-N-neotetraose (Galbeta1-->4GlcNAcbeta1-->3Galbeta1-->4Glc; paraglobosyl; monoclonal antibodies (mAbs) 1B2(+) and 06B4(+)) and GalNAc-->lacto-N-neotetraose (gangliosyl; mAb 1-1-M+) oligosaccharides. Ion peaks for a larger LOS which also bound mAb 1B2 indicated the addition of a hexose (+162 Da) to gangliosyl LOS or the addition of a hexose and a N-acetylhexosamine (+365 Da) to paraglobosyl LOS. Analysis of HF-treated and O-deacylated LOS revealed three major components present in a phosphoethanolamine (PEA)0 and a PEA1 series. Digestion of MS11mkC LOS by beta-N-acetylhexosaminidase and beta-galactosidase, alone and sequentially, combined with mAb binding patterns, confirmed the presence of a nonreducing terminal repeating LacNAc ((Galbeta1-->4GlcNAc)2) on the largest LOS, rather than a parallel oligosaccharide structure.     

A subpopulation of reactive astrocytes at the immediate site of cerebral cortical injury

Data presented in this paper show that bromhexine and its pharmacologically active metabolite can easily be determined by capillary zone electrophoresis. The composition of the running buffer had a significant effect on the reproducibility of the migration time for which a carrier solution containing 30 mM phosphate buffer (pH 3.0), 5 M urea and 10% (v/v) acetonitrile was used. The method was validated with respect to its response linearity and reproducibility. The method is suitable for the determination of bromhexine and ambroxol in several samples such as pharmaceuticals, urine and serum. Photodiode-array detection permitted the rapid identification of both drugs in the sample analyzed.     

Rotavirus and reovirus interaction with mouse peritoneal resident phagocytic cells

Rotaviruses and reoviruses are involved in human and animal diseases. It is known that both viruses penetrate the gastrointestinal tract but their interaction with phagocytic cells is unknown. To study this interaction, peritoneal resident phagocytic cells were used and rotavirus and reovirus replication in peritoneal phagocytic cells was observed. However, rotavirus replication in these cells led to the production of defective particles since MA-104 cells inoculated with rotavirus phagocytic cell lysate did not show any evidence of virus replication. On the basis of these results, we suggest that, although reovirus dissemination may be helped by these phagocytic cells, these cells may control rotavirus infection and probably contribute to the prevention of its dissemination.     

Short- and long-term multilineage repopulating hematopoietic stem cells in late fetal and newborn mice: models for human umbilical cord blood

Blood from late fetal and newborn mice is similar to umbilical cord blood obtained at birth in human beings, an important source of stem cells for clinical transplantation. The mouse model is useful because long-term functions can be readily assayed in vivo. To evaluate the functions of hematopoietic precursors in the blood and other tissues of late fetal and newborn mice, short- and long-term multilineage repopulating abilities were measured in vivo by competitive repopulation. Manipulations that might affect cell function, such as enrichment, tissue culture, or retroviral marking, were avoided. Hematopoietic stem cell functions of late fetal or newborn blood, liver, and spleen, were assayed as myeloid and lymphoid repopulating abilities relative to standard adult marrow cells. Donor cells from these tissues as well as adult control donor marrow cells were all of the same genotype. Cells from each donor tissue were mixed with portions from a pool of standard adult "competitor" marrow distinguished from the donors by genetic differences in hemoglobin and glucosephosphate isomerase. After 21 to 413 days, percentages of donor type myeloid and lymphoid cells in recipient blood were measured to assay the functional abilities of donor precursors relative to the standard. These relative measures are expressed as repopulating units, where each unit is equivalent to the repopulating ability found in 100,000 standard adult marrow cells. Thus, measures of repopulating units do not compare single cells but overall repopulating abilities of donor cell populations. Relative functional abilities in 1 million nucleated cells from late fetal or newborn blood were several times less than those found in adult marrow, but far more than in normal adult blood, and appeared to include long-term functional primitive hematopoietic stem cells (PHSC) similar to those in marrow. To estimate functional abilities of individual PHSC, variances among large groups of identical recipients were analyzed using both the binomial model and competitive dilution, a new model based on the Poisson distribution. The data best fit the hypothesis that individual PHSC from adult marrow, late fetal blood, or newborn blood each produce similar fractions of the total lymphoid and erythroid cells found in the recipient for many months.     

The use of natural interferon alpha conjugated to a monoclonal antibody anti mammary epithelial mucin (Mc5) for the treatment of human breast cancer xenografts

An immunoconjugate composed of natural interferon alpha (nIFN alpha) bound in a noncleavable fashion to a monoclonal antibody (MoAb) recognizing a breast epithelial membrane mucin (Mc5) was used to to treat xenografts of a human mammary carcinoma cell line (MCF-7) growing in nude mice. The immunoconjugate (nIFN alpha/Mc5) was administered as 20 intralesional (i.l.) injections to 1 of 2 xenografts in each animal. It was found that nIFN alpha/Mc5 produced a significant enhancement of the growth inhibitory actions of nIFN alpha on the injected tumors. Further enhancement was obtained when nIFN gamma or nIFN gamma together with Mc5 (at a dose 10 times larger than that present in nIFN alpha/Mc5) were added to the immunoconjugate. Biodistribution experiments showed that the uptake of 125I-nIFN alpha/Mc5 by the tumors was greater and its elimination slower than for 125I-nIFN alpha alone or conjugated to irrelevant mouse IgG1. In addition, the immunoconjugate up-regulated the antigenic expression of a breast epithelial membrane mucin by the carcinoma cells, an up-regulation which was not significantly different from that produced by nIFN alpha alone. The contralateral noninjected tumors exposed to systemic levels of the immunoconjugate showed an enhancement of antitumor effects, but to a lesser extent than the injected tumors. These findings suggest that the enhancement of the growth inhibitory action of the immunoconjugate was related to the specific binding of Mc5 which targeted the IFN to the carcinoma cells and impeded its elimination. It is likely that the targeting was favored by the IFN-mediated up-regulation of antigenic expression by the carcinoma cells, thereby producing a cascade of interrelated effects. The results of this study point out the feasibility and potential usefulness of IFN treatment by means of immunoconjugates as well as the worth of pursuing and improving this form of therapy.     

A single point mutation in the yeast TRP4 gene affects efficiency of mRNA 3' end processing and alters selection of the poly(A) site

The yeast TRP4 mRNA 3' end formation element is a bidirectional element which functions in both orien-tations in an artificial in vivo test system. In this study, the role of 3' end formation was analysed in the context of the entire TRP4 gene. The 3' untranslated region (3'UTR) of TRP4 was altered and changes were analysed for their influence on TRP4 gene expression. The 3'UTR in reverse orientation was fully functional and did not affect TRP4 gene expression. Exchanging the TRP4 3'UTR by the bidirectional ARO4 or the unidirectional GCN4 3' end formation element allowed efficient gene expression. Deletion of the entire TRP4 3'UTR resulted in 70% reduction of TRP4 mRNA and 50% reduced specific Trp4 enzyme activity in comparison to wild-type. A single point mutation within the TRP4 3'UTR caused the same effect on gene expression. This point mutation did not only affect the efficiency of 3' end formation, but also produced new poly(A) sites which were situated upstream of the wild-type poly(A) sites. Therefore this sequence motif in the TRP4 3'UTR acts simultaneously as both an efficiency and positioning element.     

The crystal structure of human procathepsin K

Cathepsin K is a cysteine protease present in human osteoclasts that plays an important role in bone resorption. Cathepsin K is synthesized as an inactive proenzyme and activated under conditions of low pH. Autoproteolytic processing of the N-terminal 99 amino acid propeptide produces the active, mature form of cathepsin K. It is presumed that the activation of procathepsin K in vivo occurs in the bone resorption pit, which has a low-pH environment. We have determined the structure of human procathepsin K at 2.8 A resolution. The structure of the mature enzyme domain within procathepsin K is virtually identical to that of mature cathepsin K. The fold of the propeptide of procathepsin K is similar to that observed in procathepsins B and L despite differences in length and sequence. A portion of the propeptide occupies the active site cleft of cathepsin K. Hydrophobic interactions, salt bridges, and hydrogen-bonding interactions are observed in the structure of the propeptide and between the propeptide and the mature enzyme of procathepsin K. These interactions suggest an explanation for the stability of the proenzyme. The structure of procathepsin K contributes to an understanding of the molecular basis of inhibition by the propeptide portion of the molecule and activation of this important member of the cysteine protease family.