G-protein dissociation, GTP-GDP exchange and GTPase activity in control and PMA treated neutrophils stimulated by fMet-Leu-Phe

The addition of the chemotactic factor fMet-Leu-Phe to cell homogenates causes a decrease in the pertussis toxin catalyzed ADP-ribosylation of a 41 kDa protein. The fMet-Leu-Phe induced decrease is not abolished in homogenates prepared from phorbol 12-myristate 13-acetate treated neutrophils. This decreased ribosylation probably reflects a dissociation of the GTP-binding protein oligomer that is not followed by association, possibly because of the release of the alpha-subunit into the suspending medium. Furthermore, fMet-Leu-Phe stimulates the binding of radiolabelled guanylylimidodiphosphate to membrane preparations. Again, the stimulated binding of guanylylimidodiphosphate is not affected by treating the intact neutrophils with phorbol 12-myristate 13-acetate. In addition leukotriene B4, platelet activating factor and fMet-Leu-Phe activate a high-affinity GTPase in membrane preparations. The basal level of this GTPase activity is dramatically inhibited in membrane preparations isolated from cells treated with phorbol 12-myristate 13-acetate. On the other hand, the fMet-Leu-Phe stimulated component is only marginally reduced. The present findings suggest that PMA does not prevent receptor G-protein interaction.     

CORRESPONDENCE BETWEEN PHYLOGENY AND MORPHOLOGY OF SNOWELLA SPP. AND WORONICHINIA NAEGELIANA,CYANOBACTERIA COMMONLY OCCURRING IN LAKES1

In this study, the first reported isolates of the genera Snowella and Woronichinia were characterized by 16S rRNA gene sequencing and morphological analysis. Phylogenetic studies and sequences for these genera were not available previously. By botanical criteria, the five isolated strains were identified as Snowella litoralis (Häyrén) Komárek et Hindák Snowella rosea (Snow) Elenkin and Woronichinia naegeliana (Unger) Elenkin. This study underlines the identification of freshly isolated cultures, since the Snowella strains lost the colony structure and were not identifiable after extended laboratory cultivation. In the 16S rRNA gene analysis, the Snowella strains formed a monophyletic cluster, which was most closely related to the Woronichinia strain. Thus, our results show that the morphology of the genera Snowella and Woronichinia was in congruence with their phylogeny, and their phylogeny seems to support the traditional botanical classification of these genera. Furthermore, the genera Snowella and Woronichinia occurred commonly and might occasionally be the most abundant cyanobacterial taxa in mainly oligotrophic and mesotrophic Finnish lakes. Woronichinia occurred frequently and also formed blooms in eutrophic Czech reservoirs.     

Ruddy turnstones Arenaria interpres rapidly build pectoral muscle after raptor scares

To cope with changes in the environment, organisms not only show behavioural but also phenotypic adjustments. This is well established for the digestive tract. Here we present a first case of birds adjusting their flight machinery in response to predation risk. In an indoor experiment, ruddy turnstones Arenaria interpres were subjected to an unpredictable daily appearance of either a raptor or a small gull (as a control). Ruddy turnstones experiencing threat induced by a flying raptor model, longer than after similar passage by the gull model, refrained from feeding after this disturbance. Pectoral muscle mass, but not lean mass, responded in a course of a few days to changes in the perceived threat of predation. Pectoral muscle mass increased after raptor scares. Taking the small increases in body mass into account, pectoral muscle mass was 3.6% higher than aerodynamically predicted for constant flight performance. This demonstrates that perceived risk factors may directly affect organ size.     

Plague Meningitis—A Retrospective Analysis of Cases Reported in the United States, 1970-1979

Meningitis caused by Yersinia pestis developed in 6 (6%) of a total of 105 patients with plague reported to the Centers for Disease Control from 1970 to 1979. Five of the six cases occurred in children aged 10 to 15 years. All six patients received antibiotic therapy before meningitis developed, which appeared between the 9th and 14th days after the onset of acute illness in five of the six patients. There were no neurologic sequelae. The antigenic and biochemical profiles of the Y pestis strains isolated from cerebrospinal fluid in the meningitis cases did not differ from those of the Y pestis strains obtained from blood and bubo aspirates in the other 99 patients, and neither did in vitro studies suggest antibiotic resistance. While plague meningitis is an uncommon complication of acute plague infection, physicians in the western United States should be aware that it may develop as much as 14 days after antibiotic therapy for the acute plague infection has been initiated.