Ribosomal RNA sequence phylogeny is not congruent with ascospore morphology among species in Ceratocystis sensu stricto

The genus Ceratocystis sensu stricto includes important fungal pathogens of woody and herbaceous plants. This genus is distinguished from species in Ceratocystis sensu lato by the presence of Chalara anamorphs. Ascospore shape has been used extensively in delineating Ceratocystis taxa, which show a large variety of ascospore shapes. Sequence analysis of one region of he 18S ribosomal RNA subunit and two regions of the 28S ribosomal RNA subunit showed that there was a majority of multiple substitutions at nucleotide sites and that there was a low transition/transversion ratio, T = 0.72. Both of these results suggest that these are well established, old species. Ascospore morphology, for the most part, was not congruent with the molecular phylogeny, and the use of morphological characters may be misleading in the taxonomy of these species.      

Membrane compartmentalized ATP and its preferential use by the Na, K-ATPase of human red cell ghosts

This paper describes work which begins to define the molecular organization in the region of the membrane that comprises the functional domain of the Na:K pump. The membrane-bound phosphoglycerate kinase (PGK) and Na, K-ATPase appear to be directly linked via a compartmentalized form of ATP. Evidence for the membrane pool of ATP is based on the labeling characteristics of the phosphoproteins by [γ-(32)P]ATP of ghosts incubated under various conditions. Preincubation of ghosts in the presence of ATP at 37 degrees C, but not at 0 degrees C, completely obscures the formation of the Na-phosphoprotein in ghosts washed and subsequently incubated in the presence of [gamma-(32)P]ATP. In contrast to the Na component, the Mg component of phosphorylation is only slightly altered by preincubation with ATP. ATPase activity measured as (32)P(i) liberated during the subsequent incubation at 0 degrees C, reflects completely the differential effects of preincubation with ATP on (32)P incorporation into phosphoprotein. ATP placed within the pool by preincubation can be removed by operating the Na, K-ATPase or the PGK reaction in the reverse direction by use of exogenous substrates. Alternatively, the membrane pool of ATP can be formed also from exogenous substrates by running the PGK reaction in the forward direction. These results, while providing direct support for a membrane compartment of ATP, also indicate the location of this compartment in relation to the PGK and the Na, K-ATPase. In addition, these results also imply that the Mg and Na components are different enzymatic entities since substrate ATP can be derived from separate sources.     

Properties of the complex between histone H1 and poly(ADP-ribose synthesised in HeLa cell nuclei

Preparations of H1 histone from HeLa cell nuclei incubated with [3H]NAD to permit poly(ADP-ribose) synthesis were electrophoresed on polyacrylamide gels. The incorporated radioactivity migrated as a sharply defined peak in association with a protein band which moved more slowly than H1, the major protein component. The following observations indicate that this complex is composed of two molecules of H1 and a single chain of poly(ADP-ribose) with one detectable covalent linkage of polymer to protein. 1. The [14C]arginine/[3H]lysine ratio is identical in H1 histone and in the protein moiety of the complex. 2. Protein is displaced from H1 histone to the complex during poly(ADP-ribose) synthesis. At least 90% of the protein in the complex (stainable protein and labelled protein) is derived from H1. 3. Sedimentation rate studies indicate a molecular weight of the complex about twice that of H1 histone. 4. The average chain length of the polymer is 15 ADP-ribose units and there are 7--8 ADP-ribose units for each molecule of H1 histone in the 'complex'. 5. Poly(ADP-ribose) glycohydrolase, which hydrolyses the polymer exoglycosidically from the AMP terminus, degrades the complex producing ADP-ribose and mono-ADP-ribosylated H1 histone which co-electrophoreses with unmodified H1. Although only one covalent linkage between protein and polymer has been detected, the 'complex' does not dissociate when electrophoresed on dodecylsulfate gels. Nor can the noncovalently linked H1 histone of the complex readily exchange with free H1. Complex formation does not occur when purified poly(ADP-ribose) and H1 are mixed.     

Dynamics of correlated genetic systems III. Behaviour of chromosomal segments under lethal selection

The effect of lethal selection on linked marker loci was investigated in experimental populations of Drosophila melanogaster. Replicate experimental populations were initiated using flies heterozygous for the lethal gene Stubble and with the enzyme loci esterase-C and phosphoglucomutase in linkage disequilibrium with Stubble. The dynamical behavior of the lethal and marker genes was followed through generation 41 when the experimental was terminated. The major findings of the experiment are: (1) the lethal gene was eliminated from all replicate populations; (2) the marker gene frequency behavior could not be accounted for by lethal selection and recombination alone; and (3) linkage disequilibrium among the marker genes stabilized at high levels. The results of this experiment are contrasted with those of a previous experiment, of similar design, involving the lethal gene Glued. New data from generations 40 and 41 of the Glued experiment are also presented. The qualitative agreement among experiments are also presented. The both experiments indicate the existence of other strongly selected factors in the region spanned by the marker genes.This research was supported in part by National Science Foundation grants GB41116 and DEB76-82479.     

Can transposable elements be used to drive disease refractoriness genes into vector populations?

A number of biological procedures are currently being considered as alternatives to insecticide-based methods for the control of insect vectors of disease. Among these are the adaptation of various genetic mechanisms to drive genes of interest, such as refractoriness to malaria in mosquitoes, into natural populations, for vector control purposes. Here, Margaret Kidwell and Jose Ribeiro develop a rationale for the possible use of transposable genetic elements, one of these potential drive mechanisms, and some of the problems being faced in seeking to determine the feasibility of such a strategy are described.     

An enzyme electrode for amperometric measurement of D-amino acid

A carbon paste enzyme electrode has been developed for measurement of D-amino acids that employs a fatty acid modified FAD to prevent leaching of this essential cofactor to the surrounding aqueous environment and which serves as an enzyme stabilizing agent. The lower limit of detection is at least 10(-4) M and the electrode has a linear range of 10(-4) to 3 x 10(-3) M and a response time of 180 s. Twenty L-amino acids were tested and none of them elicited responses when electrodes were exposed to 0.5 mM concentration increases over a baseline level. On the other hand, some response was observed when exposed to 18 of 20 D-amino acids varying from 2 to 200% of the corresponding D-alanine response. Electrodes were shown to have longevities of over 30 days while maintaining 85% of their original sensitivity. Electrodes showed activity over a pH of 6.2-11.7 with a maximum at 9.2 and over temperatures of 10-47 degrees C with a maximum at 37 degrees C.     

Treatment and outcome of patients with metastatic NSCLC: a retrospective institution analysis of 493 patients

Background

Most patients with metastatic non-small cell lung cancer (NSCLC) will face treatment with systemic therapy. Current clinical studies are demonstrating improvements in chemotherapy and overall survival. However, it remains unclear whether these results are translated into clinical practice.

Methods

We reviewed all stage IV NSCLC patients without second malignancies that were diagnosed from 2004 to 2006 at our institution. 493 consecutive patients were included into this retrospective analysis and were followed-up until end of 2011.

Results

352 patients (71.4%) received systemic therapy for up to 7 lines. For most patients, adjustments of dosages or applications had to be made at some point of the treatment, but the total applied dose remained generally close to the intended dose. The best disease control (BDC) rate decreased with increasing therapy lines from 59.7% to about 35%. Patients with palliative local therapy but no systemic treatment demonstrated inferior survival (median 2.9 versus 8.7 months, p < 0.001). The median interval between last treatment and death was 50 days and 15 days for chemotherapy and anti-EGFR therapy, respectively. BDC to the previous therapy lines was predictive for improved BDC to third- but not second-line therapy. Performing multivariate analysis, BDC to previous therapy, never-/ former-smoking status, and age > 70 years were associated with improved survival performing third-line therapy.

Conclusions

Stage IV NSCLC patients may receive substantial systemic therapy resulting in response and median survival rates that are comparable to data from clinical studies. However, preselection factors are increasingly important to improve therapy outcome and life quality.     

Chytrid epidemics may increase genetic diversity of a diatom spring-bloom

Contrary to expectation, populations of clonal organisms are often genetically highly diverse. In phytoplankton, this diversity is maintained throughout periods of high population growth (that is, blooms), even though competitive exclusion among genotypes should hypothetically lead to the dominance of a few superior genotypes. Genotype-specific parasitism may be one mechanism that helps maintain such high-genotypic diversity of clonal organisms. Here, we present a comparison of population genetic similarity by estimating the beta-dispersion among genotypes of early and peak bloom populations of the diatom Asterionella formosa for three spring-blooms under high or low parasite pressure. The Asterionella population showed greater beta-dispersion at peak bloom than early bloom in the 2 years with high parasite pressure, whereas the within group dispersion did not change under low parasite pressure. Our findings support that high prevalence parasitism can promote genetic diversification of natural populations of clonal hosts.