Myeloperoxidase and eosinophil cationic protein in serum and sputum during antibiotic treatment in cystic fibrosis patients with Pseudomonas aeruginosa infection

I order to study the time-course of myeloperoxidase (MPO) and eosinophil cationic protein (ECP) as parameters for monitoring inflammation in cystic fibrosis (CF), we investigated ten patients during both a 14-day intravenous antibiotic treatment and a corresponding self control. Modified Shwachman-Kulczycki score improved significantly (p < 0.008), C-reactive protein (CRP) levels decreased significantly (p < 0.05) during antibiotic treatment, while in the control phase there were no significant differences. Lung function parameters did not change significantly during antibiotic treatment or control phase. Serum MPO concentration (p < 0.006) and peripheral blood neutrophil granulocyte counts (p < 0.04) decreased significantly during antibiotic treatment, but not during the control phase. Sentm ECP concentration showed a tendency to decrease during antibiotic treatment, but this failed to reach significance. In general, sputum concentrations of MPO and ECP Were 500- to 1000-fold higher than in serum. However, neither MPO nor ECP in sputum showed a significan variation over time during antibiotic treatment or control phase. From our data we conclude that: (1) measurements of MPO, neutrophils and CRP in peripheral blood do correlate with clinical parameters such as the modified Shwachman-Kulczycki score; (2) neutrophils and MPO seem to reflect inflammatory changes induced by antibiotic treatment; (3) eosinophils may play a role in CF by an enhanced 'releasability' and (4) Sputum measurements of mediators of inflammation cannot be recommended.     

Direct isolation in cell-free medium of a spiroplasma fromHaemaphysalis leporispalustris (Acari: Ixodidae) in Maryland

A spiroplasma isolate, was obtained from rabbit ticks (Haemaphysalis leporispalustris) taken from cottontail rabbits in Maryland by inoculation of tick suspensions into SP-4 medium. The isolate was indistinguishable from an experimental vertebrate pathogen (suckling mouse cataract agent spiroplasma) when tested with other plant and tick spiroplasmas in growth inhibition, deformation, and metabolism inhibition tests. The isolated organism had a pathogenic profile for suckling rats and embryonated chicken eggs that differed significantly from that of other suckling mouse cataract agent strains. This is the first report of a direct spiroplasma isolation from ticks in cell-free medium, and confirms the specific association of spiroplasmas of the suckling mouse cataract agent serogroup with rabbit ticks.     

Nephroblastoma in infants, 1969-75: variations in treatment and survival.

In a series of 79 infants aged under 1 year with nephroblastoma diagnosed during 1969-75 all the patients underwent nephrectomy, 33 (42%) received a course of radiotherapy, and 49 (62%) received chemotherapy. The overall three-year survival rate for patients who survived at least one week after diagnosis was 65%. The corresponding rate for infants with stage I tumours was 76%. The survival rate in children with early-stage tumours was significantly higher in those who were treated by nephrectomy and chemotherapy alone compared with those who also received radiotherapy. In a large proportion of cases nephrectomy and chemotherapy together constituted sufficient treatment for the cure of infants with nephroblastoma, and in some instances nephrectomy alone proved adequate. There was no general tendency for children under 1 year old to be unable to withstand chemotherapy.     

Genomic Evidence for Island Population Conversion Resolves Conflicting Theories of Polar Bear Evolution

Despite extensive genetic analysis, the evolutionary relationship between polar bears (Ursus maritimus) and brown bears (U. arctos) remains unclear. The two most recent comprehensive reports indicate a recent divergence with little subsequent admixture or a much more ancient divergence followed by extensive admixture. At the center of this controversy are the Alaskan ABC Islands brown bears that show evidence of shared ancestry with polar bears. We present an analysis of genome-wide sequence data for seven polar bears, one ABC Islands brown bear, one mainland Alaskan brown bear, and a black bear (U. americanus), plus recently published datasets from other bears. Surprisingly, we find clear evidence for gene flow from polar bears into ABC Islands brown bears but no evidence of gene flow from brown bears into polar bears. Importantly, while polar bears contributed <1% of the autosomal genome of the ABC Islands brown bear, they contributed 6.5% of the X chromosome. The magnitude of sex-biased polar bear ancestry and the clear direction of gene flow suggest a model wherein the enigmatic ABC Island brown bears are the descendants of a polar bear population that was gradually converted into brown bears via male-dominated brown bear admixture. We present a model that reconciles heretofore conflicting genetic observations. We posit that the enigmatic ABC Islands brown bears derive from a population of polar bears likely stranded by the receding ice at the end of the last glacial period. Since then, male brown bear migration onto the island has gradually converted these bears into an admixed population whose phenotype and genotype are principally brown bear, except at mtDNA and X-linked loci. This process of genome erosion and conversion may be a common outcome when climate change or other forces cause a population to become isolated and then overrun by species with which it can hybridize.     

Mdm10 is an ancient eukaryotic porin co-occurring with the ERMES complex

Mitochondrial β-barrel proteins fulfill central functions in the outer membrane like metabolite exchange catalyzed by the voltage-dependent anion channel (VDAC) and protein biogenesis by the central components of the preprotein translocase of the outer membrane (Tom40) or of the sorting and assembly machinery (Sam50). The mitochondrial division and morphology protein Mdm10 is another essential outer membrane protein with proposed β-barrel fold, which has so far only been found in Fungi. Mdm10 is part of the endoplasmic reticulum mitochondria encounter structure (ERMES), which tethers the ER to mitochondria and associates with the SAM complex. In here, we provide evidence that Mdm10 phylogenetically belongs to the VDAC/Tom40 superfamily. Contrary to Tom40 and VDAC, Mdm10 exposes long loops towards both sides of the membrane. Analyses of single loop deletion mutants of Mdm10 in the yeast Saccharomyces cerevisiae reveal that the loops are dispensable for Mdm10 function. Sequences similar to fungal Mdm10 can be found in species from Excavates to Fungi, but neither in Metazoa nor in plants. Strikingly, the presence of Mdm10 coincides with the appearance of the other ERMES components. Mdm10's presence in both unikonts and bikonts indicates an introduction at an early time point in eukaryotic evolution.     

Transformation of Lotus japonicus using the herbicide resistance bar gene as a selectable marker

Transgenic plants of the model legume Lotus japonicus were regenerated by hypocotyl transformation using a bar gene as a selectable marker. The bar encodes for Phosphinothricin Acetyl Transferase that detoxifies phosphinothricin (PPT), the active ingredient of herbicides such as Ignite (AgrEvo) and Basta (Hoechst). Transgenic L. japonicus plants resistant to PPT were positive upon PCR by bar gene-specific primers. In 5 out of 7 independent lines tested, PPT resistance segregated as a single dominant allele indicating a single T-DNA insertion into the plant genome. All regenerated plants were fertile and void of visible somaclonal abnormalities contrary to 14% infertility when antibiotic selectable markers were used. The lack of somaclonal variation, ease of PPT application and low cost of PPT makes this protocol an attractive alternative for the regeneration of transgenic L. japonicus. The production of PPT herbicide-resistant L. japonicus plants may have significant commercial applications in crop production.     

Long-branch attraction and the rDNA model of early eukaryotic evolution

Phylogenetic analyses of ribosomal RNA genes have become widely accepted as a framework for understanding broad-scale eukaryotic evolution. Nevertheless, conflicts exist between the phylogenetic placement of certain taxa in rDNA trees and their expected position based on fossils, cytology, or protein-encoding gene sequences. For example, pelobiont amoebae appear to be an ancient group based on cytologic features, but they are not among the early eukaryotic brances in rDNA analyses. In this report, the derived position of pelobionts in rDNA trees is shown to be unreliable and likely due to long-branch attraction among more deeply branching sequences. All sequences that branch near the base of the tree suffer from relatively high apparent substitution rates and exhibit greater variation in ssu rDNA sequence length. Moreover, the order of the branches leading from the root of the eukaryotic tree to the base of the so-called "crown taxa" is consistent with a sequential attachment, due to "long-branch" effects, of sequences with increasing rates of evolution. These results suggest that the basal eurkaryotic topology drawn from rDNA analyses may be, in reality, an artifact of variation in the rate of molecular evolution among eukaryotic taxa.     

Symbiotic mutants deficient in nodule establishment identified after T-DNA transformation of Lotus japonicus

Nitrogen-fixing root nodules develop on legumes as a result of an interaction between host plants and soil bacteria collectively referred to as rhizobia. The organogenic process resulting in nodule development is triggered by the bacterial microsymbiont, but genetically controlled by the host plant genome. Using T-DNA insertion as a tool to identify novel plant genes that regulate nodule ontogeny, we have identified two putatively tagged symbiotic loci, Ljsym8 and Ljsym13, in the diploid legume Lotus japonicus. The sym8 mutants are arrested during infection by the bacteria early in the developmental process. The sym13 mutants are arrested in the final stages of infection, and ineffective nodules are formed. These two plant mutant lines were identified in progeny from 1112 primary transformants obtained after Agrobacterium tumefaciens T-DNA-mediated transformation of L. japonicus and subsequent screening for defects in the symbiosis with Mesorhizobium loti. Additional nontagged mutants arrested at different developmental stages were also identified and genetic complementation tests assigned all the mutations to 16 monogenic symbiotic loci segregating recessive mutant alleles. In the screen reported here independent symbiotic loci thus appeared with a frequency of ～1.5%, suggesting that a relatively large set of genes is required for the symbiotic interaction.     

Early steps in plastid evolution: current ideas and controversies

Some nuclear‐encoded proteins are imported into higher plant plastids via the endomembrane (EM) system. Compared with multi‐protein Toc and Tic translocons required for most plastid protein import, the relatively uncomplicated nature of EM trafficking led to suggestions that it was the original transport mechanism for nuclear‐encoded endosymbiont proteins, and critical for the early stages of plastid evolution. Its apparent simplicity disappears, however, when EM transport is considered in light of selective constraints likely encountered during the conversion of stable endosymbionts into fully integrated organelles. From this perspective it is more parsimonious to presume the early evolution of post‐translational protein import via simpler, ancestral forms of modern Toc and Tic plastid translocons, with EM trafficking arising later to accommodate glycosylation and/or protein targeting to multiple cellular locations. This hypothesis is supported by both empirical and comparative data, and is consistent with the relative paucity of EM‐based transport to modern primary plastids.