Mechanisms of bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is a chronic lung disease affecting premature infants with long term effect on lung function into adulthood. Multiple factors are involved in the development of BPD. This review will summarize the different mechanisms leading to this disease and highlight recent bench and clinical research targeted at understanding the role of the mesenchyme (both its cellular and extracellular components) in the pathogenesis of BPD.     

Yeast ribosomal protein L7 and its homologue Rlp7 are simultaneously present at distinct sites on pre-60S ribosomal particles

Ribosome biogenesis requires >300 assembly factors in Saccharomyces cerevisiae. Ribosome assembly factors Imp3, Mrt4, Rlp7 and Rlp24 have sequence similarity to ribosomal proteins S9, P0, L7 and L24, suggesting that these pre-ribosomal factors could be placeholders that prevent premature assembly of the corresponding ribosomal proteins to nascent ribosomes. However, we found L7 to be a highly specific component of Rlp7-associated complexes, revealing that the two proteins can bind simultaneously to pre-ribosomal particles. Cross-linking and cDNA analysis experiments showed that Rlp7 binds to the ITS2 region of 27S pre-rRNAs, at two sites, in helix III and in a region adjacent to the pre-rRNA processing sites C₁ and E. However, L7 binds to mature 25S and 5S rRNAs and cross-linked predominantly to helix ES7^Lb within 25S rRNA. Thus, despite their predicted structural similarity, our data show that Rlp7 and L7 clearly bind at different positions on the same pre-60S particles. Our results also suggest that Rlp7 facilitates the formation of the hairpin structure of ITS2 during 60S ribosomal subunit maturation.     

Anxiolytic Properties of New Chemical Entity, 5TIO1

2-[(2,6-dichlorobenzylidene)amino]-5,6-dihydro-4H-cyclopenta[b]thiophene-3-carbonitrile), 5TIO1, is a new 2-aminothiophene derivative with a promising pharmacological activity. The aim of this work was to evaluate the potential anxiolytic effect of 5TIO1 in animal models. In the elevated plus-maze test, 5TIO1 (0.1, 1.0 and 10.0 mg/kg, i.p) increased the time of permanence and the number of entries in the open arms. In the light/dark box test, 5TIO1 at dose of 0.1 mg/kg (i.p) also showed anxiolytic-like effect indicated by an increase in the time spent in the light box, similar to diazepam 2.0 mg/kg (i.p). 5TIO1 groups did not change locomotor and coordination activities in open field and rotarod tests, respectively, when compared to vehicle. Dose dependent process was not observed and the anxiolytic effects demonstrated were not completely reversed by flumazenil 25 mg/kg (i.p). Our results suggest that 5TIO1 can bind with other receptors, besides the benzodiazepine site of the GABA receptor in mouse brain.     

2-(1H-Pyrazol-4-yl)acetic acids as CRTh2 antagonists

High throughput screening identified the pyrazole-4-acetic acid substructure as CRTh2 receptor antagonists. Optimisation of the compounds uncovered a tight SAR but also identified some low nanomolar inhibitors.     

A conserved ClpP‐like protease involved in spore outgrowth in Bacillus subtilis

Germination and outgrowth of endospores of the Gram‐positive bacterium Bacillus subtilis involves the degradation and conversion to free amino acids of abundant proteins located in the spore core known as small acid‐soluble proteins (SASP). This degradation is mediated primarily by the germination protease Gpr. Here we show that YmfB, a distant homologue of ClpP serine proteases that is highly conserved among endospore‐forming bacteria, contributes to SASP degradation but that its function is normally masked by Gpr. Spores from a ymfB gpr double mutant were more delayed in spore outgrowth and more impaired in SASP degradation than were spores from a gpr single mutant. The activity of YmfB relied on three putative active‐site residues as well as on the product of a small gene ylzJ located immediately downstream of, and overlapping with, ymfB. We propose that YmfB is an orphan ClpP protease that is dedicated to the degradation of a specialized family of small protein substrates.     

Community-wide plasmid gene mobilization and selection

Plasmids have long been recognized as an important driver of DNA exchange and genetic innovation in prokaryotes. The success of plasmids has been attributed to their independent replication from the host''s chromosome and their frequent self-transfer. It is thought that plasmids accumulate, rearrange and distribute nonessential genes, which may provide an advantage for host proliferation under selective conditions. In order to test this hypothesis independently of biases from culture selection, we study the plasmid metagenome from microbial communities in two activated sludge systems, one of which receives mostly household and the other chemical industry wastewater. We find that plasmids from activated sludge microbial communities carry among the largest proportion of unknown gene pools so far detected in metagenomic DNA, confirming their presumed role of DNA innovators. At a system level both plasmid metagenomes were dominated by functions associated with replication and transposition, and contained a wide variety of antibiotic and heavy metal resistances. Plasmid families were very different in the two metagenomes and grouped in deep-branching new families compared with known plasmid replicons. A number of abundant plasmid replicons could be completely assembled directly from the metagenome, providing insight in plasmid composition without culturing bias. Functionally, the two metagenomes strongly differed in several ways, including a greater abundance of genes for carbohydrate metabolism in the industrial and of general defense factors in the household activated sludge plasmid metagenome. This suggests that plasmids not only contribute to the adaptation of single individual prokaryotic species, but of the prokaryotic community as a whole under local selective conditions.     

Drug Resistance in Natural Isolates of Leishmania donovani s.l. Promastigotes Is Dependent of Pgp170 Expression

Resistance of pathogens to drugs is a growing concern regarding many diseases. Parasites like Leishmania, Plasmodium and Entamoeba histolytica; and neoplastic cells, present the multidrug-resistant phenotype rendering chemotherapy ineffective. The acquired resistance of Leishmania to antimony has generated intense research on the mechanisms involved but the question has not yet been resolved. To test the hypothesis that drug efflux in Leishmania, as measured by flow cytometry using the fluorescent dye Rhodamine-123, is largely dependent on the number of efflux pumps an isolate can express, the amount of Pgp 170 molecules was assessed in ten field isolates (5 “resistant” and 5 “susceptible”) using: Western Blotting, Confocal and Transmission Electron Microscopy, and proteomics. Their survival after exposure to three antileishmanial drugs, in vitro, was evaluated and clinical data were compared to the in vitro results. All isolates were resistant to Glucantime but susceptible to Miltefosine, whilst Amphotericin B was more effective on the “susceptible” isolates. The MDR gene, expressing the transmembrane efflux pump Pgp 170, appears to play a key role in the phenomenon of drug resistance. When “susceptible” versus “resistant” parasites were compared, it was shown that the higher the number of Pgp 170 molecules the higher the Rhodamine-123 efflux from the parasite body and, when exposed to the drug, the number of efflux pumps increased. However, the rate of this increase was not linear and it is possible that there is a maximum number of Pgp 170 molecules an isolate can express. Nevertheless, the phenomenon is a complex one and other factors and proteins are involved in which the HSP-70 group proteins, detected in the “resistant” isolates, may play a significant role.