Characterization of cDNA clones for human myeloperoxidase: predicted amino acid sequence and evidence for multiple mRNA species.

Myeloperoxidase is a component of the microbicidal network of polymorphonuclear leukocytes. The enzyme is a tetramer consisting of two heavy and two light subunits. A large proportion of humans demonstrate genetic deficiencies in the production of myeloperoxidase. As a first step in analyzing these deficiencies in more detail, we have isolated cDNA clones for myeloperoxidase from an expression library of the HL-60 human promyelocytic leukemia cell line. Two overlapping plasmids (pMP02 and pMP062) were identified as myeloperoxidase cDNA clones based on the detection with myeloperoxidase antiserum of 70 kDa protein expressed in pMP02-containing bacteria and a 75 kDa polypeptide produced by hybridization selection and translation using pMP062 and HL-60 RNA. Formal identification of the clones was made by matching the predicted amino acid sequences with the amino terminal sequences of the heavy and light subunits. Both subunits are encoded by one mRNA in the following order: pre-pro-sequences--light subunit--heavy subunit. The molecular weight of the predicted primary translation product is 83.7 kDa. Northern blots reveal two size classes of hybridizing RNAs (approximately 3.0-3.3 and 3.5-4.0 kilobases) whose expression is restricted to cells of the granulocytic lineage and parallels the changes in enzymatic activity observed during differentiation.     

Alpha-inhibin gene expression occurs in the ovine adrenal cortex, and is regulated by adrenocorticotropin

Inhibin is a glycoprotein hormone composed of two nonidentical subunits. It is produced by the ovary and testis and plays a vital role in gonadal function by inhibiting the secretion of FSH. More recently, additional activities associated with inhibin peptides have been identified. Inhibin heterodimers (alpha-beta) are reported to act directly on ovarian granulosa cells and inhibit estrogen production induced by FSH. Furthermore, homodimers of beta-inhibin subunits stimulate the secretion of FSH, an activity that is directly opposite to that of inhibin. Each of these inhibin-related activities are concerned with the hypothalamic-pituitary-gonadal axis. We have investigated further the complexity of inhibin activity by determining whether inhibin genes are expressed in nongonadal tissue. RNA hybridization experiments demonstrate that the alpha-inhibin gene is expressed in the sheep adrenal cortex and hybridization histochemistry shows that this gene is expressed in each of the functional zones within the cortex. Dot blot analysis showed that the level of alpha mRNA within the adrenal is influenced by ACTH, one of the major regulators of adrenal cortex function. These observations imply that there are inhibin-related peptides not directly associated with the gonads. beta-inhibin gene expression was not clearly detected in the adrenal and we conclude that if expression occurs then it does so at extremely low levels.     

Childhood asthma in adult life: a further study at 28 years of age.

A group of 323 subjects who had wheezed in childhood and 48 control subjects of the same age were studied prospectively from 7 to 28 years of age. A classification system based on wheezing frequency was found to correlate well with clinical and spirometric features of airway obstruction. The amount of wheezing in early adolescence seemed to be a guide for severity in later life with 73% of those with few symptoms at 14 continuing to have little or no asthma at 28 years. Similarly 68% of those with frequent wheezing at 14 still suffered from recurrent asthma at 28 years. Most subjects with frequent wheezing at 21 continued to have comparable asthma at 28 years. Of those with infrequent wheezing at 21, 44% had worsened at 28 years. Women fared better than men between 21 and 28 with 19% having worse symptoms compared with 28% of men. Treatment at all ages was generally inadequate. The number of smokers among those with asthma was of concern.     

Structure of the tryptic glycopeptide isolated from rabbit transferrin.

The structure of the tryptic glycopeptide isolated from rabbit transferrin was elucidated by use of sequential Edman degradations, specific exoglycosidases, endo-beta-N-acetylglucosaminidases, methylation analyses, and periodate oxidation studies. The glycopeptide consists of a heteropolysaccharide, AcNeualpha2 leads to 6Galbeta1 leads to 4GlcNAcbeta1 leads to 2Manalpha1 leads to 3[AcNeualpha2 leads to 6Galbeta1 leads to 4GlcNAcbeta1 leads to 2Manalpha1 leads to 6]-Manbeta1 leads to 4GlcNAcbeta1 leads to 4GlcNAc, attached to a peptide, Asn-Ser-Ser-Leu-Cys, via a linkage involving N-acetyl-glucosamine and asparagine. The stoichiometry of this glycopeptide is 2 mol/mol of protein, indicating that rabbit transferrin contains two structurally identical glycopeptide segments.     

Follicle development, blood feeding, digestion and egg maturation in diapausing mosquitoes, Culiseta inornata

Female Culiseta inornata (Williston) caught at Edmonton, Canada, in September and October were nulliparous, had small ovarian follicles and did not take blood meals in nature. Most newly collected females did feed on the author in the laboratory, but the blood meals were small and ejected prematurely, there was no trypsin activity and no egg maturation. In some females that were kept for 7 days at 16 hr daylength and 20°, follicle growth and yolk deposition occurred, and in such females, blood feeding was followed by egg maturation. Follicle development also occurred in females that had been kept for 2–3 months at 12 hr daylength and 5°, and although blood feeding rates were low, trypsin activity and egg maturation were observed in all blood-fed females. Ovarian diapause in C. inornata may be considered terminated when the ratio of the length of a typical follicle to the length of its germarium has reached 2.0.

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Zusammenfassung In Zentral-Alberta (Kanada) erscheinen die diapausierenden Weibchen von Culiseta inornata (Williston), die Überwinterungsform, im August. Weibchen, die im September gesammelt wurden, legten keine Eier, hatten kleine Eifollikel und nahmen im Freien keine Blutnahrung auf. Die meisten frisch gesammelten Weibchen saugten im Laboratorium Blut am Autor, doch war die Blutmenge gering und wurde bald wieder ausgestossen. Es wurde keine Trypsinaktivität und keine Eireifung festgestellt. Bei einigen Weibchen, die während 7 Tagen bei einer Photoperiode von 16 Stunden und 20° gehalten wurden, kam es zu Follikelwachstum und Dotterablagerung. Bei diesen Weibchen folgte Eireifung auf die Blutaufnahme. Follikelentwicklung setzte auch ein bei Weibchen, die für 2–3 Monate bei 12 Stunden-Tag und 5° gehalten worden waren. Obwohl die Blutaufnahme gering war, wurde Trypsinaktivität und Eireifung bei allen blutgefütterten Weibchen beobachtet. Die Ovarialdiapause bei C. inornata kann als beendet betracht werden, wenn das Verhältnis der Länge eines typischen Follikels zur Länge seines Germarium 2.0 erreicht hat.

     

Engineered antibody fragments and the rise of single domains

With 18 monoclonal antibody (mAb) products currently on the market and more than 100 in clinical trials, it is clear that engineered antibodies have come of age as biopharmaceuticals. In fact, by 2008, engineered antibodies are predicted to account for >30% of all revenues in the biotechnology market. Smaller recombinant antibody fragments (for example, classic monovalent antibody fragments (Fab, scFv)) and engineered variants (diabodies, triabodies, minibodies and single-domain antibodies) are now emerging as credible alternatives. These fragments retain the targeting specificity of whole mAbs but can be produced more economically and possess other unique and superior properties for a range of diagnostic and therapeutic applications. Antibody fragments have been forged into multivalent and multi-specific reagents, linked to therapeutic payloads (such as radionuclides, toxins, enzymes, liposomes and viruses) and engineered for enhanced therapeutic efficacy. Recently, single antibody domains have been engineered and selected as targeting reagents against hitherto immunosilent cavities in enzymes, receptors and infectious agents. Single-domain antibodies are anticipated to significantly expand the repertoire of antibody-based reagents against the vast range of novel biomarkers being discovered through proteomics. As this review aims to show, there is tremendous potential for all antibody fragments either as robust diagnostic reagents (for example in biosensors), or as nonimmunogenic in vivo biopharmaceuticals with superior biodistribution and blood clearance properties.     

The occurrence of Campylobacter subtypes in environmental reservoirs and potential transmission routes

AIM: To identify potential reservoirs and transmission routes of human pathogenic Campylobacter spp. METHODS AND RESULTS: An enrichment PCR method for the detection and identification of Campylobacter jejuni and/or Campylobacter coli in faecal, food and river water samples was applied to 1450 samples of 12 matrix types obtained from a defined geographical area. PCR-positive samples were cultured to yield isolates for typing, and the data for 616 C. jejuni isolates obtained. Serotyping and SmaI macrorestriction profiling using pulsed field gel electrophoresis revealed a high level of diversity within the isolates from each matrix. Campylobacter jejuni and C. coli subtypes indistinguishable from those obtained from human cases were detected in most of the matrices examined. No Campylobacter isolates were isolated from possum faeces. CONCLUSIONS: Ten of the 12 matrices examined may be involved in the transmission of human campylobacteriosis as they contained Campylobacter subtypes also isolated from clinical cases. SIGNIFICANCE AND IMPACT OF THE STUDY: Results indicate that, for this rural population, a range of potential transmission routes that could lead to campylobacteriosis exist. Their relative importance needs to be assessed from an exposure assessment standpoint.     

Validation of alternative methods of data normalization in gene co-expression studies

MOTIVATION: Clusters of genes encoding proteins with related functions, or in the same regulatory network, often exhibit expression patterns that are correlated over a large number of conditions. Protein associations and gene regulatory networks can be modelled from expression data. We address the question of which of several normalization methods is optimal prior to computing the correlation of the expression profiles between every pair of genes. RESULTS: We use gene expression data from five experiments with a total of 78 hybridizations and 23 diverse conditions. Nine methods of data normalization are explored based on all possible combinations of normalization techniques according to between and within gene and experiment variation. We compare the resulting empirical distribution of gene x gene correlations with the expectations and apply cross-validation to test the performance of each method in predicting accurate functional annotation. We conclude that normalization methods based on mixed-model equations are optimal.     

Evaluation of chiral discrimination of highly negatively charged enantiomers by quaternary ammonium beta-cyclodextrin using 1H NMR

The positively charged quaternary ammonium cyclodextrin, QA-beta-CD, was previously used as a chiral selector to achieve baseline resolution of two of the dianionic enantiomers of disodium 3-(p-isothiocyanatophenoxy)-3-(p-isothiocyanatophenyl)propane-1,2-disulfate by capillary electrophoresis. The basis of the chiral discrimination between QA-beta-CD and the enantiomers was investigated by (1)H NMR spectroscopy. COSY and NOESY spectra were used to infer the role that molecular interactions and the stereocenters have upon association of QA-beta-CD with the enantiomers. A parallel two-step complexation model is used to rationalize the NMR and the chiral discrimination observed during separation of the enantiomers.