Composition, and antimicrobial and remarkable antiprotozoal activities of the essential oil of rhizomes of Aframomum sceptrum K. Schum. (Zingiberaceae)

The essential oil from the rhizomes of Aframomum sceptrum (Zingiberaceae) was analyzed by GC/MS, and its major constituents were found to be β‐pinene (12.7%), caryophyllene oxide (10.0%), and cyperene (6.0%). The oil was also evaluated for antimicrobial activities, in comparison with β‐pinene, caryophyllene oxide, and the leaf essential oil of Melaleuca alternifolia (Myrtaceae). The A. sceptrum essential oil exhibited bacteriostatic activity against the Gram‐positive bacteria Bacillus subtilis, Staphylococcus epidermidis, and S. aureus, but not against Gram‐negative bacteria. Moreover, it showed mild fungicidal activity against Candida albicans and Aspergillus fumigates, and remarkable antiprotozoal activity against Trypanosoma brucei brucei (MLC of 1.51 μl/ml) and Trichomonas vaginalis (IC₅₀ of 0.12±0.02 and MLC of 1.72 μl/ml).     

How allometric scaling relates to soil abiotics

For most species, the logarithm of their average body mass is negatively related to the logarithm of their relative population density, i.e. the numerical abundance. In this way, the allometric scaling (both mass–abundance regressions and body–size spectra) becomes useful in ecological theory to build and explain food webs. Using empirical evidence derived from 145 Dutch sites, a hypothesis is formulated to explain how soil microbivores, detritivores and predators react to increasing resource availability. Shifts in size distribution, and subsequently changes in soil food‐web structure, are further discussed in the perspective of Holling's sequential interactions between basic system functions. We show that the allometric scaling and the averages of the (log‐transformed) prey:predator body‐mass ratios are reliable predictors for assessing faunal responses to nutrient availability. We view this work as a first attempt toward an extensive comparison of ecological processes in different soil systems.     

Hyperosmotic stress induces Axl activation and cleavage in cerebral endothelial cells

Because of the relative impermeability of the blood‐brain barrier (BBB), many drugs are unable to reach the CNS in therapeutically relevant concentration. One method to deliver drugs to the CNS is the osmotic opening of the BBB using mannitol. Hyperosmotic mannitol induces a strong phosphorylation on tyrosine residues in a broad spectrum of proteins in cerebral endothelial cells, the principal components of the BBB. Previously, we have shown that among targets of tyrosine phosphorylation are β‐catenin, extracellular signal‐regulated kinase 1/2 and the non‐receptor tyrosine kinase Src. The aim of this study was to identify new signalling pathways activated by hypertonicity in cerebral endothelial cells. Using an antibody array and immunoprecipitation we identified the receptor tyrosine kinase Axl to become tyrosine phosphorylated in response to hyperosmotic mannitol. Besides activation, Axl was also cleaved in response to osmotic stress. Degradation of Axl proved to be metalloproteinase‐ and proteasome‐dependent and resulted in 50–55 kDa C‐terminal products which remained phosphorylated even after degradation. Specific knockdown of Axl increased the rate of apoptosis in hyperosmotic mannitol‐treated cells; therefore, we assume that activation of Axl may be a protective mechanism against hypertonicity‐induced apoptosis. Our results identify Axl as an important element of osmotic stress‐induced signalling.     

Inhalation of an endothelin receptor A antagonist attenuates pulmonary inflammation in experimental acute lung injury

We recently demonstrated that inhalation of the endothelin receptor A (ETA) antagonist LU 135252 improved arterial oxygenation and reduced pulmonary artery pressure in experimental acute lung injury (ALI). In this study we analyzed potential immune modulatory effects of inhaled LU 135252 in experimental ALI. ALI was induced by repeated lung lavage in intubated (100% O2) and anesthetized piglets. Animals were randomly assigned to inhale either nebulized LU 135252 (0.3 mg.kg-1, ALI + LU group, n = 8) or saline buffer (ALI control group, n = 16), both for 30 min. Surviving animals were sacrificed 6 h after induction of ALI, and lung tissue specimens were obtained from all animals for histology and immunhistochemistry. Induction of ALI significantly decreased arterial oxygenation in all animals. Inhalation of LU 135252 significantly reduced mortality and induced significant and sustained increase in Pao2 (316 +/- 47 mm Hg vs. control 53 +/- 3 mm Hg, p < 0.001). We measured a significant reduction in the number of pulmonary leukocyte L1 antigen-positive cells in ALI + LU animals (8% +/- 1% positive cells vs. control 12% +/- 2% positive cells, p < 0.05). The number of CD3-positive cells was not altered by treatment with LU 135252. Pulmonary tissue concentration of IL-6 was significantly suppressed by LU 135252 inhalation (4 +/- 1 pg.100 mg-1 wet weight vs. control 7 +/- 1 pg.100 mg-1 wet weight, p < 0.05). Concentrations of TNF-alpha, IL-1beta, and ET-1 in pulmonary tissue were not influenced by inhalation of LU 135252. In conclusion, we demonstrated that inhalation of LU 135252 not only improves mortality and gas exchange, but also blunts the local immune response in experimental ALI.     

Systems biology-defined NF-κB regulons, interacting signal pathways and networks are implicated in the malignant phenotype of head and neck cancer cell lines differing in p53 status

Background  

Aberrant activation of the nuclear factor kappaB (NF-κB) pathway has been previously implicated as a crucial signal promoting tumorigenesis. However, how NF-κB acts as a key regulatory node to modulate global gene expression, and contributes to the malignant heterogeneity of head and neck cancer, is not well understood.     

Phylogenetic position of the langur genera <Emphasis Type="Italic">Semnopithecus</Emphasis> and <Emphasis Type="Italic">Trachypithecus</Emphasis> among Asian colobines,and genus affiliations of their species groups

Background  

The evolutionary history of the Asian colobines is less understood. Although monophyly of the odd-nosed monkeys was recently confirmed, the relationships among the langur genera Presbytis, Semnopithecus and Trachypithecus and their position among Asian colobines remained unclear. Moreover, in Trachypithecus various species groups are recognized, but their affiliations are still disputed. To address these issues, mitochondrial and Y chromosomal sequence data were phylogenetically related and combined with presence/absence analyses of retroposon integrations.     

The genetic variability of the red king crab, <Emphasis Type="Italic">Paralithodes camtschatica</Emphasis> (Tilesius, 1815) (Anomura,Lithodidae) introduced into the Barents Sea compared with samples from the Bering Sea and Kamchatka region using eleven microsatellite loci

The intentional introduction of red king crab, Paralithodes camtschatica (Tilesius, 1815) in the Barents Sea represent one of a few successful cases and one that now supports a commercial fishery. Introductions of alien species into new environments are often associated with genetic bottlenecks, which cause a reduction in the genetic variation, and this could be important for the spreading potential of the species in the Atlantic Ocean. Red king crab samples collected in the Varangerfjord located on the Barents Sea (northern Norway) were compared with reference crab samples collected from the Bering Sea and Kamchatka regions in the Pacific Ocean. All samples were screened for eleven microsatellite loci, based on the development of species-specific primers. The observed number of alleles per locus was similar, and no reduction in genetic variation, including gene diversity and allelic richness, was detected between the Varangerfjord sample and the reference sample from Okhotsk Sea near Kamchatka, indicating no genetic bottlenecking at least for the microsatellite loci investigated. The same results were found in comparison with the sample from Bering Sea. The level of genetic differentiation among the samples, measured as overall F _ST across all loci, was relatively low (0.0238) with a range of 0.0035–0.1000 for the various loci investigated. The largest pairwise F _ST values were found between the Bering Sea and Varangerfjord/Barents Sea samples, with a value of 0.0194 across all loci tested. The lowest value (0.0101) was found between the Varangerfjord and Kamchatka samples. Genetic differentiation based on exact tests on allele frequencies revealed highly significant differences between all pairwise comparisons. The high level of genetic variation found in the Varangerfjord/Barents Sea sample could be of significance with respect to further spreading of the species to other regions in the North Atlantic Ocean.     

Mechanism of shortened action potential duration in Na+-Ca2+ exchanger knockout mice

In cardiac-specific Na⁺-Ca²⁺ exchanger (NCX) knockout (KO) mice, the ventricular action potential (AP) is shortened. The shortening of the AP, as well as a decrease of the L-type Ca²⁺ current (I_Ca), provides a critical mechanism for the maintenance of Ca²⁺ homeostasis and contractility in the absence of NCX (Pott C, Philipson KD, Goldhaber JI. Excitation-contraction coupling in Na⁺-Ca²⁺ exchanger knockout mice: reduced transsarcolemmal Ca²⁺ flux. Circ Res 97: 1288–1295, 2005). To investigate the mechanism that underlies the accelerated AP repolarization, we recorded the transient outward current (I_to) in patch-clamped myocytes isolated from wild-type (WT) and NCX KO mice. Peak I_to was increased by 78% and decay kinetics were slowed in KO vs. WT. Consistent with increased I_to, ECGs from KO mice exhibited shortened QT intervals. Expression of the I_to-generating K⁺ channel subunit Kv4.2 and the K⁺ channel interacting protein was increased in KO. We used a computer model of the murine AP (Bondarenko VE, Szigeti GP, Bett GC, Kim SJ, and Rasmusson RL. Computer model of action potential of mouse ventricular myocytes. Am J Physiol Heart Circ Physiol 287: 1378–1403, 2004) to determine the relative contributions of increased I_to, reduced I_Ca, and reduced NCX current (I_NCX) on the shape and kinetics of the AP. Reduction of I_Ca and elimination of I_NCX had relatively small effects on the duration of the AP in the computer model. In contrast, AP repolarization was substantially accelerated when I_to was increased in the computer model. Thus, the increase in I_to, and not the reduction of I_Ca or I_NCX, is likely to be the major mechanism of AP shortening in KO myocytes. The upregulation of I_to may comprise an important regulatory mechanism to limit Ca²⁺ influx via a reduction of AP duration, thus preventing Ca²⁺ overload in situations of reduced myocyte Ca²⁺ extrusion capacity. genetically altered mice; cardiac myocytes; short QT interval; transient outward current