Functional anatomy of the musculature of the trachea.

The smooth musculature of the human trachea was studied and compared with earlier observations in the rabbit. The results may be summarized as follows: 1. The annular m. constrictor tracheae, previously observed in the rabbit, has also been identified in the human trachea. 2. Longitudinal muscle fibers outside the constrictor musculature were observed in man. These fibers are rudimentary and appear to be of no functional importance. 3. From a functional point of view, it appears justified to regard the outer tracheal musculature largely as a constrictor musculature. 4. The main function of the outer musculature of the trachea and the elastic cartilaginous arches is to maintain the stability of the tracheal wall. 5. The variation of the lumen of the trachea is mainly controlled by the m. trachealis in the pars membranacea.     

Chemical composition of lipopolysaccharides from Legionella bozemanii and Legionella longbeachae

Lipopolysaccharides (LPS) from Legionella bozemanii serogroup 1 and Legionella longbeachae serogroup 1 were subjected to chemical analyses. The lipid A part of both LPSs contained 2,3-dideoxy-2,3-diamino-d-glucose as major constituents and d-glucosamine and glycerol as minor constituents of the sugar backbone structure. Both LPSs exhibited a very complex fatty acid composition. Twenty amide-linked 3-hydroxy fatty acids were detected in LPS of L. longbeachae, whereas seventeen were encountered in LPS of L. bozemanii. Both LPSs contained nine ester-linked nonhydroxy fatty acids and the unique long-chain fatty acids 27-oxo-octacosanoic acid, 29-oxotriacontanoic acid, heptacosane-1,27-dioic acid and nonacosane-1,29-dioic acid. SDS-PAGE showed that L. bozemanii produced smooth-form LPS, whereas L. longbeachae LPS was mainly of the R-type. Composition analyses were in accordance with these electrophoretic patterns. d-Quinovosamine and l-fucosamine constituted 80 mol% of the polysaccharide part of L. bozemanii LPS. Other sugars identified were d-glucosamine, d-mannose, d-glucose, l-rhamnose, d-glycero-d-manno-heptose, l-glycero-d-mannoheptose, 2-keto-3-deoxy-octonic acid and glycerol. The polysaccharide chain from LPS of L. longbeachae appeared to be shorter, but composed of the same sugars except l-fucosamine. Both LPSs contained glycerol phosphate and glucosamine phosphate and L. longbeachae LPS contained in addition glucose phosphate.Abbreviations EI Electron impact - GlcN3N 2,3-Diamino-2,3-dideoxy-d-glucose - HPAEC High pH anion-exchange chromatography - Kdo 2-Keto-3-deoxy-octonic acid - LPS Lipopolysaccharide - PCP Phenol/chloroform/petroleum ether solvent - PED Pulsed electrochemical detection - PS Polysaccharide - TFA Trifluoroacetyl - TMS Trimethylsilyl     

Genotypic difference in salinity tolerance in quinoa is determined by differential control of xylem Na loading and stomatal density

Quinoa is regarded as a highly salt tolerant halophyte crop, of great potential for cultivation on saline areas around the world. Fourteen quinoa genotypes of different geographical origin, differing in salinity tolerance, were grown under greenhouse conditions. Salinity treatment started on 10 day old seedlings. Six weeks after the treatment commenced, leaf sap Na and K content and osmolality, stomatal density, chlorophyll fluorescence characteristics, and xylem sap Na and K composition were measured. Responses to salinity differed greatly among the varieties. All cultivars had substantially increased K⁺ concentrations in the leaf sap, but the most tolerant cultivars had lower xylem Na⁺ content at the time of sampling. Most tolerant cultivars had lowest leaf sap osmolality. All varieties reduced stomata density when grown under saline conditions. All varieties clustered into two groups (includers and excluders) depending on their strategy of handling Na⁺ under saline conditions. Under control (non-saline) conditions, a strong positive correlation was observed between salinity tolerance and plants ability to accumulate Na⁺ in the shoot. Increased leaf sap K⁺, controlled Na⁺ loading to the xylem, and reduced stomata density are important physiological traits contributing to genotypic differences in salinity tolerance in quinoa, a halophyte species from Chenopodium family.     

Recombinant human serum amyloid P component from Pichia pastoris: production and characterization

Human serum amyloid P component (SAP) was expressed in the methylotrophic yeast Pichia pastoris. SAP cDNA was placed under control of regulatory sequences derived from the alcohol oxidase gene (AOX1), and its protein product was secreted using the Saccharomyces cerevisiae alpha-mating factor signal sequence. Recombinant SAP (r-SAP) was produced in a bioreactor with computer controlled fed-batch mode and purified by use of a C-terminal histidine tag. The yield of purified r-SAP was 3-4mg from 1L supernatant and 5-6mg from 1L cell paste, indicating that the majority of the produced SAP was not secreted. Treatment of the cell paste with EDTA increased the yield further by about 30%. The N-terminal of r-SAP purified from the supernatant showed non-complete cleavage of the alpha-mating factor signal sequence. Purified r-SAP, analyzed under native conditions, was shown to be a decamer, like purified human SAP (h-SAP), with monomers of 27kDa. Each monomer had one N-glycosylation site, positioned at the same site as for h-SAP. r-SAP bound to antibodies produced against h-SAP. Furthermore, r-SAP bound to ds DNA and influenza A virus subunits in a Ca(2+)-dependent manner and inhibited influenza A virus hemagglutination. These results indicate that r-SAP produced in P. pastoris has the same biological activity as purified h-SAP.     

Actin-like protein associated with plasma membranes fromEuglena gracilis

Summary Microtubules are characteristic components of the membrane skeleton ofEuglena gracilis, but whether microfilaments are present has been controversial. We here present evidence that an actin-like protein may indeed be associated with the plasma membrane (PM) ofE. gracilis. Firstly, a 47 kDa, PM-associated, polypeptide was recognized by an anti-amoeba actin antibody. Secondly, this 47 kDa protein seemed to be peripherally attached to PM in much the same way as -tubulin, since both could be released from PM by treatment with 150 mM NaOH but not with ethylene glycol, NaCl, or formamide. Thirdly, the 47 kDa polypeptide and -tubulin were found mainly in the Triton X-1 14-insoluble fraction, indicating that they were part of a protein complex resistant to detergents, such as the cytoskeleton. Finally, DNase I activity was inhibited by a fraction enriched in the 47 kDa polypeptide, a property typical of actin.Abbreviations CP-medium cytoskeleton preparation medium - BNSP-skatole 2-(2-nitrophenylsulfenyl)-3-methyl-3-bromoindolenine - ECL enhanced chemiluminescence - HEPES N-[2-hydroxyethyl]-piperazine-N[2-ethane sulfonic acid] - ICM intracellular membranes - MF mitochondrial and microsomal fraction - PM plasma membrane - PPB potassium phosphate buffer - PVDF polyvinylidene difluoride - SDS sodium dodecyl sulphate - TBS Tris-buffered saline - TBST Tris-buffered saline with Tween 20     

Molecular mechanisms of congenital heart block

Autoantibody-associated congenital heart block (CHB) is a passively acquired autoimmune condition associated with maternal anti-Ro/SSA antibodies and primarily affecting electric signal conduction at the atrioventricular node in the fetal heart. CHB occurs in 1–2% of anti-Ro/SSA antibody-positive pregancies and has a recurrence rate of 12–20% in a subsequent pregnancy. Despite the long-recognized association between maternal anti-Ro/SSA autoantibodies and CHB, the molecular mechanisms underlying CHB pathogenesis are not fully understood, but several targets for the maternal autoantibodies in the fetal heart have been suggested. Recent studies also indicate that fetal susceptibility genes determine whether an autoantibody-exposed fetus will develop CHB or not, and begin to identify such genes. In this article, we review the different lines of investigation undertaken to elucidate the molecular pathways involved in CHB development and reflect on the hypotheses put forward to explain CHB pathogenesis as well as on the questions left unanswered and that should guide future studies.     

Endothelium-dependent vascular responses induced by leukotriene B4

Leukotriene B(4) (LTB(4)) is an inflammatory mediator derived from the 5-lipoxygenase pathway of arachidonic acid metabolism and has recently implicated in the pathogenesis of atherosclerosis. There are two membrane bound receptors for LTB(4): BLT(1) and BLT(2), which represent the high and low affinity receptors, respectively. BLT receptors are expressed on leukocytes, and LTB(4) is a potent chemoattractant for neutrophils, eosinophils, and T lymphocytes. Recent studies have in addition shown that LTB(4) is an indirectly acting vasoconstrictor of isolated vascular preparations. In the guinea pig aorta, the LTB(4)-induced contractions were inhibited by endothelium-denudation. In addition, pre-treatment with the NO synthase inhibitor, L-NOARG, significantly enhanced the contractions induced by LTB(4). The contractile response induced by LTB(4) in the guinea pig aorta was abolished by the selective BLT(1) receptor antagonist U75302 and the expression of BLT(1) receptor mRNA in the guinea pig aorta was established by RT-PCR. Taken together, these results suggest that LTB(4) activates BLT(1) receptors on the endothelium of the guinea pig aorta, associated with the release of both contractile factors and NO.     

Co-product allocation in life cycle assessments of seafood production systems: Review of problems and strategies

Background, Aim and Scope  

As Life Cycle Assessment is being increasingly applied to study fisheries and aquaculture systems, the LCA methodology must be adapted to address the unique aspects of these systems. The focus of this methodological paper is the specific allocation problems faced in studying seafood production systems and how they have been addressed to date.     

Combined detection and introgression of QTL in outbred populations

Background

Detecting a QTL is only the first step in genetic improvement programs. When a QTL with desirable characteristics is found, e.g. in a wild or unimproved population, it may be interesting to introgress the detected QTL into the commercial population. One approach to shorten the time needed for introgression is to combine both QTL identification and introgression, into a single step. This combines the strengths of fine mapping and backcrossing and paves the way for introgression of desirable but unknown QTL into recipient animal and plant lines.

Methods

The method consisting in combining QTL mapping and gene introgression has been extended from inbred to outbred populations in which QTL allele frequencies vary both in recipient and donor lines in different scenarios and for which polygenic effects are included in order to model background genes. The effectiveness of the combined QTL detection and introgression procedure was evaluated by simulation through four backcross generations.

Results

The allele substitution effect is underestimated when the favourable QTL allele is not fixed in the donor line. This underestimation is proportional to the frequency differences of the favourable QTL allele between the lines. In most scenarios, the estimates of the QTL location are unbiased and accurate. The retained donor chromosome segment and linkage drag are similar to expected values from other published studies.

Conclusions

In general, our results show that it is possible to combine QTL detection and introgression even in outbred species. Separating QTL mapping and introgression processes is often thought to be longer and more costly. However, using a combined process saves at least one generation. With respect to the linkage drag and obligatory drag, the results of the combined detection and introgression scheme are very similar to those of traditional introgression schemes.     

The DEAD-box helicase DDX3 supports the assembly of functional 80S ribosomes

The DEAD-box helicase DDX3 has suggested functions in innate immunity, mRNA translocation and translation, and it participates in the propagation of assorted viruses. Exploring initially the role of DDX3 in the life cycle of hepatitis C virus, we observed the protein to be involved in translation directed by different viral internal ribosomal entry sites. Extension of these studies revealed a general supportive role of DDX3 in translation initiation. DDX3 was found to interact in an RNA-independent manner with defined components of the translational pre-initiation complex and to specifically associate with newly assembling 80S ribosomes. DDX3 knock down and in vitro reconstitution experiments revealed a significant function of the protein in the formation of 80S translation initiation complexes. Our study implies that DDX3 assists the 60S subunit joining process to assemble functional 80S ribosomes.