Identification of the major site of in vitro PKA phosphorylation in the polycystin-1 C-terminal cytosolic domain.

Sequence analysis of the C-terminal cytosolic domain of human and mouse polycystin-1 has identified three RxS consensus protein kinase A (PKA) phosphorylation motifs. GST-fusion proteins containing the full-length and truncated C-terminal cytosolic domain of murine polycystin-1 were phosphorylated in vitro by the purified catalytic subunit of PKA. This identified a sequence of 25 amino acids, immediately downstream of a previously identified heterotrimeric G-protein activation sequence, as the major site of PKA phosphorylation. Phosphorylation of wild-type and alanine substituted synthetic peptides containing this motif demonstrated that alanine substitution of serine 4159 largely eliminated phosphorylation. Mutation of this residue in the fusion protein reduced phosphorylation by about 70%, whereas mutation of the other two conserved phosphorylation motifs had little effect. We conclude that serine 4159 is the major site of PKA phosphorylation in the C-terminal cytosolic domain of murine polycystin-1.     

Hemodynamics of miniature swine during +Gz stress with and without anti-G support

Nine unanesthetized, chronically instrumented, female miniature swine (MS) (avg wt, 39.7 kg) were exposed to head-to-tail inertial load (+Gz) levels of +3, +5, and +7 Gz for 60 s, with and without anti-G-suit inflation. Venous flow (VF) was measured by an electromagnetic flow sensor around the inferior thoracic vena cava at the diaphragm. Central venous pressure (CVP), abdominal venous pressure (AVP), eye-level blood pressure (ELBP), and esophageal pressure (EP) were also measured before, during, and after +Gz. There was a progressive significant decrease from control of both ELBP (P less than 0.001) and VF (P less than 0.05) during the three +Gz exposures, both with and without G-suit inflation. Without G-suit inflation, most of the MS were unable to tolerate +5 and +7 Gz. Although VF was significantly (P less than 0.02) improved by G-suit inflation during +Gz there was no significant difference in VF between the three +Gz levels, with or without G-suit inflation. The MS does a spontaneous straining maneuver (cyclic Valsalva) during +Gz with G-suit support. Using EP as a trigger, the data were grouped as strain or no strain (relaxation). A continuous AVP-to-CVP gradient existed during G-suit inflation, which increased dramatically during no strain with increasing +Gz, and was associated with an increase in VF. Thus, the majority of VF occurred during relaxation between strains, even though relaxation time was shortened as +Gz increased. Although ELBP is obviously dependent on cardiac output and venous return, the progressive reduction in ELBP with increased +Gz loads was not significantly related to changes in VF at the diaphragm which was maintained, although at a reduced rate, by the AVP-to-CVP gradient during G-suit inflation.     

Buxus sirindhorniana sp. nov. (Buxaceae), a bicarpellate species from Thailand

A new bicarpellate Buxus species, Buxus sirindhorniana W. K. Soh, M. von Sternburg, Hodk. & J. Parn., is described from northern Thailand. This is the first reported bicarpellate species of Buxus. The pollen morphology and the degree of pollen viability of the species are reported. DNA was extracted from herbarium samples and the internal transcribed spacer (ITS) region of nuclear ribosomal DNA sequenced. The palynological evidence and the phylogenetic reconstruction support the contention that this new species belongs to the genus Buxus. The morphological diversity of reproductive organs in the Buxaceae, in relation to this new species, is briefly discussed.     

Effects of cyanobacterial extracellular products and gibberellic acid on salinity tolerance in Oryza sativa L

The XI International Rotifer Symposium was held during 11–18 March, 2006 at the National Autonomous University of Mexico Campus Iztacala located at the North Mexico City (Mexico). These triennial international meetings, first organized in Austria by Late Ruttner-Kolisko in September 1976, are gradually becoming the focal point of discussion and collaboration from rotifer workers across the world. The present XI symposium was attended by 125 participants from 20 nations. During this meeting, different themes of rotifer research from morphology to molecular biology were considered. In addition, there were four invited lectures and four workshops covering different themes of the symposium. During the last 30 years, rotifer research has witnessed gradual shift from the conventional morphological taxonomy to molecular and evolutionary systematics. While the basic rotifer ecological studies continue today, applied areas such as ecotoxicology and aquaculture have taken key roles in the recent meetings. The international rotifer meetings provide ample opportunities not only for exchange of ideas and recent research, but also for material and in establishing inter-personal relationships. Over the last 30 years, the number of participants attending the rotifer meetings has increased.