Leaky intra-acinar arteries in rat lungs perfused with hydrogen peroxide

We have investigated the effects of H2O2 (150 or 300 microM) on the ultrastructure and permeability of the pulmonary endothelium in rat lungs perfused for 60 min with buffered Hanks' bovine serum albumin medium. In one group of experiments, we examined the effect of H2O2 on the uptake and transport of cationized ferritin (CF) by endothelial cells in intra-acinar arteries, alveolar capillaries, and interlobular veins. The influence of the oxidant on endothelial adsorptive endocytic processes was assessed by measuring the density of ferritin particles in luminal vesicles, multivesicular bodies, and basal lamina. In a second group of experiments, we examined the effects of H2O2 on the fine structure and permeability to electron-dense macromolecules of arterial, microvascular, and venous endothelium. For this purpose, at the end of the 60-min perfusion with H2O2, CF was perfused to identify leaky vessels. We found that H2O2 caused a dose-dependent inhibition of transcytosis of CF in all vascular segments. At the lower dose of H2O2, inhibition of transcytotic activity was not associated with structural injury to the vascular endothelium or with elevation of wet-to-dry ratios. At the higher oxidant dose, inhibition of transcytosis was associated with leaky arterial endothelium and elevation of wet-to-dry ratios (6.44 +/- 0.12 vs. 5.64 +/- 0.16, P less than 0.02). The effects of H2)2 were prevented by adding catalase to the perfusate. The selective loss of structural integrity and leakiness of the arterial endothelium were diminished but not completely abolished by perfusing the oxidant retrograde from the venous side.(ABSTRACT TRUNCATED AT 250 WORDS)     

Responses of rain-forest primates to habitat disturbance: A review

The survival of primates in moderately disturbed forests is determined by a complex of variables. Correlation analyses suggest that ecological features of a species may confer a basal survival ability but that details of the form of disturbance may be crucially important. Correlation analyses reveal that body size alone is a poor predictor of primate response to moderate forest disturbance. However, when the effects of diet variables are held constant, body size more strongly correlates with survival ability (smaller species surviving better). Degree of frugivory shows a significant negative correlation with survival ability at both univariate and multivariate levels of analysis. In contrast, dietetic diversity is not correlated with survival ability at either level of analysis. Together, body size and percentage frugivory explain 44% of the variation in species’ responses to moderate habitat disturbance. Idiosyncratic responses of species can usually be traced to specific features of the changing environment, such as selective elimination of important food sources and, conversely, the presence of increased densities of particular food sources arising from the disturbance.     

Glycoalkaloids of Solanum Series Megistacrolobum and related potato cultigens

Glycoalkaloids were used as evidence of the affinities of nine taxa of Solanum Series Megistacrolobum and related potato cultigens from western Bolivia. S. boliviense, S. sanctae-rosae and S. toralapanum contain the commertetraose sugar moiety and appear to represent a relatively wild group within the Series. S. megistacrolobum, S. sogarandinum and S. raphanifolium show anomolous glycoalkaloid profiles that probably reflect hybridization associated with human disturbance. Primitive forms of the S. χ ajanhuiri cultigen are indistinguishable chemicaliy from conspecific weeds that were previously classified as S. megistacrolobum. Variation in total glycoalkaloid content within Series Megistacrolobum likely reflects direct selection by humans for reduced glycoalkaloid levels during the domestication process.     

Synthesis of oligophosphoseryl sequences occurring in casein. Identification of beta-elimination during phosphorylation

The protected oligophosphoseryl peptides from bovine caseins, Z-Xxx-(Ser[PO(OPh)2])3-Glu(OBzl)-OBzl for Xxx = Ile, Val, Gly, Leu and Ph = phenyl, were synthesized in high yields by stepwise lengthening using Boc-Ser[PO(OPh)2]-OH as acylating carboxyl component and N-ethyl-N'-(3-dimethylaminopropyl)-carbodiimide hydrochloride as coupling reagent. The hydrogenolytic deprotection (PtO2) was carried out with the valine derivative and with the tetrapeptide Ser[PO(OPh)2]3-Glu(OBz)-OBzl. Phosphorylation of oligoseryl peptides failed to give the expected products. Large scale phosphorylation of protected serine was carried out in the presence of triethylamine using absolute ether as a solvent. 2,2,2-Trichloroethyl group (Tc) was shown to be a useful phosphorus protecting moiety in phosphopeptide synthesis: Boc-Ser[PO(OTc)2]-OBzl, Z-Ser[PO(OTc)2]-OBzl and Boc-Glu(OBzl)-Ser[PO(OTc)2]-OBzl were synthesized in high yields using bis-(2,2,2-trichloroethyl) phosphochloridate.     

A strategy for high cell density culture of heterotrophic microalgae with inhibitory substrates

Substrate inhibition is one of the major problems preventing high cell densities of microalgae in heterotrophic culture, so the possibility of overcoming the problem by various culture techniques was examined. It was found that perfusion culture may be the most appropriate technique for high cell densities in heterotrophic culture using inhibitory substrates. An experimental example in which a hollow fibre cell recycle system (HFCRS) was employed to achieve high cell densities of Chlamydomonas reinhardtii on acetate under heterotrophic conditions of growth was demonstrated. The cell density in the HFCRS was much higher than that reported in the literature for this species.     

TESTS FOR ANCIENT SPECIES FLOCKS BASED ON MOLECULAR PHYLOGENETIC APPRAISALS OF SEBASTES ROCKFISHES AND OTHER MARINE FISHES

The concept of species flocks has been central to previous interpretations of patterns and processes of explosive species radiations within several groups of freshwater fishes. Here, molecular phytogenies of species-rich Sebastes rockfishes from the northeastern Pacific Ocean were used to test predictions of null theoretical models that assume random temporal placements of phylogenetic nodes. Similar appraisals were conducted using molecular data previously published for particular cichlid fishes in Africa that epitomize, by virtue of a rapid and recent radiation of species, the traditional concept of an intralacustrine “species flock.” As gauged by the magnitudes of genetic divergence in cytochrome b sequences from mitochondrial DNA, as well as in allozymes, most speciation events in the Sebastes complex were far more ancient than those in the cichlids. However, statistical tests of the nodal placements in the Sebastes phylogeny suggest that speciation events in the rockfishes were temporally nonrandom, with significant clustering of cladogenetic events in time. Similar conclusions also apply to an ancient complex of icefishes (within the Notothenioidei) analyzed in the same fashion. Thus, the rockfishes (and icefishes) may be interpreted as ancient species flocks in the marine realm. The analyses exemplified in this report introduce a conceptual and operational approach for extending the concept of species flocks to additional environmental settings and evolutionary timescales.