G Protein activation without subunit dissociation depends on a G{alpha}(i)-specific region

G proteins transmit a variety of extracellular signals into intracellular responses. The Galpha and Gbetagamma subunits are both known to regulate effectors. Interestingly, the Galpha subunit also determines subtype specificity of Gbetagamma effector interactions. However, in light of the common paradigm that Galpha and Gbetagamma subunits dissociate during activation, a plausible mechanism of how this subtype specificity is generated was lacking. Using a fluorescence resonance energy transfer (FRET)-based assay developed to directly measure mammalian G protein activation in intact cells, we demonstrate that fluorescent Galpha(i1,2,3), Galpha(z), and Gbeta(1)gamma(2) subunits do not dissociate during activation but rather undergo subunit rearrangement as indicated by an activation-induced increase in FRET. In contrast, fluorescent Galpha(o) subunits exhibited an activation-induced decrease in FRET, reflecting subunit dissociation or, alternatively, a distinct subunit rearrangement. The alpha(B/C)-region within the alpha-helical domain, which is much more conserved within Galpha(i1,2,3) and Galpha(z) as compared with that in Galpha(o), was found to be required for exhibition of an activation-induced increase in FRET between fluorescent Galpha and Gbetagamma subunits. However, the alpha(B/C)-region of Galpha(il) alone was not sufficient to transfer the activation pattern of Galpha(i) to the Galpha(o) subunit. Either residues in the first 91 amino acids or in the C-terminal remainder (amino acids 93-354) of Galpha(il) together with the alpha(B/C)-helical region of Galpha(i1) were needed to transform the Galpha(o)-activation pattern into a Galpha(i1)-type of activation. The discovery of subtype-selective mechanisms of G protein activation illustrates that G protein subfamilies have specific mechanisms of activation that may provide a previously unknown basis for G protein signaling specificity.     

Comparative thermal stabilities of recombinant adenoviruses and hexon protein

Differential scanning calorimetry was used to identify the thermal stability profile of the replication deficient and protein IX deleted recombinant adenovirus type 5 that contains the p53 transgene (rAd/p53) in phosphate buffered saline (vPBS) or 10% glycerol (TRIS/phosphate buffer). The wildtype adenovirus (Ad/WT) and purified hexon protein (major capsid protein) were also evaluated in 10% glycerol (TRIS/phosphate buffer) as controls. The thermal profile of rAd/p53 revealed three endothermic transitions (T1, T2 and T3) occurring between 25 degrees C and 90 degrees C. T1, which occurred at 46.7 degrees C in vPBS and 49.4 degrees C in TRIS/PO4 10% glycerol buffer, was irreversible following repeated scanning and attributed to the degradation of the intact vector. The latter two endothermic transitions, T2 and T3, occurring at 69 degrees C and 78 degrees C, respectively, corresponded with the two transitions of purified hexon in temperature and amount of heat absorbed. The thermal profile of Ad/WT revealed four endothermic transitions at 51.5 degrees C (T1), 70.5 degrees C (T2A), 73.6 degrees C (T2B), and 77.4 degrees C (T3). The higher temperature of degradation as well as additional transition was attributed to the presence of protein IX associated with the hexon. The positions and excess molar heat capacities of the intact rAds were found to be affected by pH, glycerol, vector concentration and the presence or absence of protein IX in the capsid. Irreversibility of T1 implied that the degradation of the intact virus may follow first-order kinetics. The thermal scan rate dependence of T1 further confirmed that degradation of the intact virus may be first-order. The apparent activation energies for the degradation of the intact vectors were determined from the scan rate dependence of T1 and shown to be affected by protein IX in the capsid and solution conditions. Analysis of rAd samples incubated at 45 degrees C by Field Emission Electron Microscopy (FESEM) confirmed that loss of single particles was first-order. Although aggregates were observed in the samples, degradation appeared to be the dominant reaction leading to disappearance of single virions from the aqueous matrix. Based on thermal and FESEM analysis, an empirical model was proposed that accounted for the disappearance of single rAd particles. At or near T1, degradation of rAd particles followed a unidirectional, pseudo-first order reaction. However, at lower temperatures, disappearance of single virions resulted from competing irreversible degradation and aggregation reactions.     

Einwirkung der Tyrosinase auf “Dopa” (zugleich: Ursachen tierischer Farbkleidung. IV)

Ohne Zusammenfassung Ein Auszug dieser Arbeit erschien unter dem Titel: Mitteilungen aus der Biologischen Versuchsanstalt der Akademie der Wissenschaften, Zoologische Abteilung. Vorstand H. Przibram. 42. Einwirkung der Tyrosinase auf “Dopa” (zugleich: Ursachen tierischer Farbkleidung IV) im Akademischen Anzeiger der Akademie der Wissenschaften in Wien Nr. 18, 1919.     

Die Puppenfärbungen des Kohlweißlings,Pieris brassicae L

Zusammenfassung Wurden die Augen verpuppungsreifer Raupen mit gelbem Lack überstrichen und die Tiere in neutraler Umgebung aufgestellt, so entstanden vorwiegend die für gelbe Umgebung charakteristischen grünen Puppen. Überstreichung der Augen mit blauer Farbe hatte die Entstehung durchweg mittlerer Puppen, wie sie auch in blauer Umgebung entstehen, zur Folge.Somit ist auch durch den positiven Erfolg der Anpassung der Beweis erbracht, daß der die Puppenfärbung bestimmende Lichteinflußdurch das Raupenauge erfolgt. Das Gegenstück zu diesem Ergebnis bilden die früheren Versuche, wonach bei Abwesenheit des Auges der Farbeneinfluß aufgehoben ist.Das Aufrechtbleiben der Farbanpassung in den seinerzeitigen Versuchen bei Überstreichen der Augen mit schwarzer Farbe und Haltung in farbigen Kästen im Tageslichte ist auf das Eindringen von Licht durch die Lackschichte zurückzuführen (vgl. Mitteil. Nr. 59L. Brecher: Die Puppenfärbungen der Vanessiden, Akad. Anz. Nr. 7 und 8, 1921).Papiere von vollkommen gleichem Helligkeitswert für das total farbenblinde Menschenauge (nachHering) ergaben als Verpuppungshintergrund dem Farbtypus nach grundverschiedene Puppen: So entstanden auf Gelb (Hering Nr. 4) durchweg die typischen grünen durchsichtigen Puppen ohne schwarze Fleckenzeichnung, dagegen auf Grau der gleichen Helligkeit für das total farbenblinde Menschenauge (Grau = Gelb Nr. 4) keine grünen, sondern die, neutralen Bedingungen entsprechenden, grünlich-grau-weißen opaken Puppen mit ausgesprochener schwarzer Fleckenzeichnung — mittlere Puppen. Hingegen hatten gelbe Papiere von verschiedenem Helligkeitswert die gleiche Wirkung auf die Puppenfärbung: So ergab auch ein ganz helles Gelb (Hering Gelb Nr. 5) die gleichen intensiv grünen Puppen wie Gelb Nr. 4, das der Helligkeit nach für das total farbenblinde Menschenauge gleichwertige helle Grau (Grau = GelbHering Nr. 5) nicht-grüne mittlere Puppen mit schwarzer Fleckenzeichnung.Diese Versuchsergebnisse bestätigen die früher auf anderen Wegen gefundenen, daß die die Puppenfärbung beeinflussenden Umgebungsfarben diesen Einfluß durch ihre spezifische Farbqualität, nicht durch bestimmte Helligkeiten, ausüben.Nachdem nunmehr erwiesen ist, daß der Lichteinflußdurch das Raupenauge erfolgt, könnten diese Versuchsergebnisse auch ein Ausdruck dafür sein, daß die Raupen Gelb von Grau gleichen Helligkeitswertes als Farbempfindung unterscheiden.Ein Auszug dieser Arbeit erschien mit gleichlautendem Titel als Mitteilung Nr. 67 aus der Biologischen Versuchsanstalt der Akademie der Wissenschaften, Zool. Abteilung, Vorstand:H. Przibram, im Akad. Sitzungsanz. Nr. 2–3. 1922.     

Efficacy of Praziquantel against Schistosoma mekongi and Opisthorchis viverrini: A Randomized, Single-Blinded Dose-Comparison Trial

Background

Schistosomiasis and opisthorchiasis are of public health importance in Southeast Asia. Praziquantel (PZQ) is the drug of choice for morbidity control but few dose comparisons have been made.

Methodology

Ninety-three schoolchildren were enrolled in an area of Lao PDR where Schistosoma mekongi and Opisthorchis viverrini coexist for a PZQ dose-comparison trial. Prevalence and intensity of infections were determined by a rigorous diagnostic effort (3 stool specimens, each examined with triplicate Kato-Katz) before and 28–30 days after treatment. Ninety children with full baseline data were randomized to receive PZQ: the 40 mg/kg standard single dose (n = 45) or a 75 mg/kg total dose (50 mg/kg+25 mg/kg, 4 hours apart; n = 45). Adverse events were assessed at 3 and 24 hours posttreatment.

Principal Findings

Baseline infection prevalence of S. mekongi and O. viverrini were 87.8% and 98.9%, respectively. S. mekongi cure rates were 75.0% (95% confidence interval (CI): 56.6–88.5%) and 80.8% (95% CI: 60.6–93.4%) for 40 mg/kg and 75 mg/kg PZQ, respectively (P = 0.60). O. viverrini cure rates were significantly different at 71.4% (95% CI: 53.4–84.4%) and 96.6% (95% CI: not defined), respectively (P = 0.009). Egg reduction rates (ERRs) against O. viverrini were very high for both doses (>99%), but slightly lower for S. mekongi at 40 mg/kg (96.4% vs. 98.1%) and not influenced by increasing diagnostic effort. O. viverrini cure rates would have been overestimated and no statistical difference between doses found if efficacy was based on a minimum sampling effort (single Kato-Katz before and after treatment). Adverse events were common (96%), mainly mild with no significant differences between the two treatment groups.

Conclusions/Significance

Cure rate from the 75 mg/kg PZQ dose was more efficacious than 40 mg/kg against O. viverrini but not against S. mekongi infections, while ERRs were similar for both doses.

Trial Registration

Controlled-Trials.com ISRCTN57714676     

Ventral rectus fascia closure on top of mesh hernia repair in the sublay technique

Sublay prosthetic herniorrhaphy has become a widely accepted procedure for incisional hernias. To evaluate the effect of fascia closure on top of mesh repair on infection, and the recurrence rate, the authors reviewed their data regarding herniorrhaphy in the sublay technique. This study was a retrospective analysis of 175 consecutive patients who underwent hernia repair by implantation of prostheses by means of the Stoppa-Rives technique from December of 1994 to December of 2001. All 175 patients had the mesh implanted in the subfascial plane, 130 received a light-weight or heavy-weight polypropylene mesh (Vypro or Prolene) (74 percent), eight had a polyester mesh (Mersilene) (5 percent), and 37 had an expanded polytetrafluoroethylene patch (Gore-Tex) (21 percent). After sublay mesh positioning, the mesh could not be covered by the fascia in 50 cases; in 31 of these cases, a second mesh was placed into the fascial defect. To evaluate the influence of the fascia closing procedure on top of the sublay mesh, three groups were differentiated: initial fascia closure (n = 125), no fascia closure and concomitant mesh interposition (n = 31), and no fascia closure without mesh interposition (n = 19). After a mean follow-up of 20 months, 11 deep prosthetic infections (8 percent) and 15 hernia recurrences (9 percent) were observed. There was an increased risk of mesh infection when the fascia could not be closed, but there was no influence of fascia closure on hernia recurrence. When the fascia was left open, the placement of a second mesh inlay technique reduced mesh infection. The authors' data give evidence that closing the ventral fascia after mesh repair in the sublay position is beneficial. When the edges of the hernia defect could not be approximated, the suturing of a second mesh into the fascia defect was a useful tool for reducing the prosthetic infection rate; however, no significant influence on hernia recurrence was observed.     

Plant Ontology (PO): a Controlled Vocabulary of Plant Structures and Growth Stages

The Plant Ontology Consortium (POC) (www.plantontology.org) is a collaborative effort among several plant databases and experts in plant systematics, botany and genomics. A primary goal of the POC is to develop simple yet robust and extensible controlled vocabularies that accurately reflect the biology of plant structures and developmental stages. These provide a network of vocabularies linked by relationships (ontology) to facilitate queries that cut across datasets within a database or between multiple databases. The current version of the ontology integrates diverse vocabularies used to describe Arabidopsis, maize and rice (Oryza sp.) anatomy, morphology and growth stages. Using the ontology browser, over 3500 gene annotations from three species-specific databases, The Arabidopsis Information Resource (TAIR) for Arabidopsis, Gramene for rice and MaizeGDB for maize, can now be queried and retrieved.