Human surfactant protein B promoter in transgenic mice: temporal, spatial, and stimulus-responsive regulation

Surfactant protein B (SP-B) is a developmentally and hormonally regulated lung protein that is required for normal surfactant function. We generated transgenic mice carrying the human SP-B promoter (-1,039/+431 bp) linked to chloramphenicol acetyltransferase (CAT). CAT activity was high in lung and immunoreactive protein localized to alveolar type II and bronchiolar epithelial cells. In addition, thyroid, trachea, and intestine demonstrated CAT activity, and each of these tissues also expressed low levels of SP-B mRNA. Developmental expression of CAT activity and SP-B mRNA in fetal lung were similar and both increased during explant culture. SP-B mRNA but not CAT activity decreased during culture of adult lung, and both were reduced by transforming growth factor (TGF)-beta(1). Treatment of adult mice with intratracheal bleomycin caused similar time-dependent decreases in lung SP-B mRNA and CAT activity. These findings indicate that the human SP-B promoter fragment directs tissue- and lung cell-specific transgene expression and contains cis-acting elements involved in regulated expression during development, fetal lung explant culture, and responsiveness to TGF-beta and bleomycin-induced lung injury.     

Plasma 3-nitrotyrosine and outcome in neonates with severe bronchopulmonary dysplasia after inhaled nitric oxide

Plasma protein levels of 3-nitrotyrosine and 3-chlorotyrosine were measured by LC-MS/MS at 0 and 72 h after the initiation of inhaled nitric oxide (INO) at 20 ppm in 22 prematurely born infants with clinically documented bronchopulmonary dysplasia. Infants were classified at the time of hospital discharge as either "off mechanical ventilation," "on mechanical ventilation," or "expired/organ failure." These outcomes were tested for association with changes in plasma levels of 3-nitrotyrosine and 3-chlorotyrosine and selected clinical risk factors. Infants whose 3-nitrotyrosine levels decreased over the 72 h period were more likely to wean off of mechanical ventilation (p =.03). There was no significant association between changes in 3-chlorotyrosne levels and outcome. After controlling for other variables, an odds ratio of 8.3 (95% CI: 1.3-54.4) for improved outcomes was observed if the 3-nitrotyrosine levels decreased. These data suggest that nitrative and oxidative stress may be related to the severity of lung disease and, consequentially, the overall outcome in this select group of infants with severe bronchopulmonary dysplasia.     

Phylogenetic utility of the nuclear gene arginine decarboxylase: an example from Brassicaceae

Arginine decarboxylase (ADC) is an important enzyme in the production of putrescine and polyamines in plants. It is encoded by a single or low-copy nuclear gene that lacks introns in sequences studied to date. The rate of Adc amino acid sequence evolution is similar to that of ndhF for the angiosperm family studied. Highly conserved regions provide several target sites for PCR priming and sequencing and aid in nucleotide and amino acid sequence alignment across a range of taxonomic levels, while a variable region provides an increased number of potentially informative characters relative to ndhF for the taxa surveyed. The utility of the Adc gene in plant molecular systematic studies is demonstrated by analysis of its partial nucleotide sequences obtained from 13 representatives of Brassicaceae and 3 outgroup taxa, 2 from the mustard oil clade (order Capparales) and 1 from the related order Malvales. Two copies of the Adc gene, Adc1 and Adc2, are found in all members of the Brassicaceae studied to data except the basal genus Aethionema. The resulting Adc gene tree provides robust phylogenetic data regarding relationships within the complex mustard family, as well as independent support for proposed tribal realignments based on other molecular data sets such as those from chloroplast DNA.      

Ltx1, a mouse locus that influences the susceptibility of macrophages to cytolysis caused by intoxication with Bacillus anthracis lethal factor, maps to chromosome 11

The lethal factor (LF) toxin that is produced by Bacillus anthracis plays an important role in the pathogenesis of anthrax. LF has mononuclear phagocyte-specific intoxicating effects that are not well understood. We have identified genetic differences in inbred mouse strains that determine whether their cultured macrophages are susceptible to the cytolytic effect of LF intoxication. Our identification of resistant and susceptible mouse strains enabled us to analyse crosses between these strains and to map a single responsible gene (called Ltx1 ) to chromosome 11. Ltx1 probably influences intoxication events that occur after the delivery of LF to the cytosol, as all mouse macrophages are killed by polypeptides containing the catalytic domain of Diphtheria toxin fused to the domain of LF required for cytosolic transport. Furthermore, the susceptibility phenotype is dominant to resistance, suggesting that resistance is caused by an absence of or polymorphism in a molecule that acts jointly with, or downstream of, the activity of LF. Our mapping of Ltx1 is a crucial first step in its positional cloning, which will provide more information about the mechanism of LF intoxication.     

Biological activity of modified and exchanged 2-amino-5-nitrothiazole amide analogues of nitazoxanide

Head group analogues of the antibacterial and antiparasitic drug nitazoxanide (NTZ) are presented. A library of 39 analogues was synthesized and assayed for their ability to suppress growth of Helicobacter pylori, Campylobacter jejuni, Clostridium difficile and inhibit NTZ target pyruvate:ferredoxin oxidoreductase (PFOR). Two head groups assayed recapitulated NTZ activity and possessed improved activity over their 2-amino-5-nitrothiazole counterparts, demonstrating that head group modification is a viable route for the synthesis of NTZ-related antibacterial analogues.