FLAVONOID EVOLUTION IN DENDROSERIS (COMPOSITAE,LACTUCEAE) FROM THE JUAN FERNANDEZ ISLANDS,CHILE

Leaf flavonoid chemistry was examined from the three subgenera and 11 species of the endemic genus Dendroseris (Compositae, Lactuceae) of the Juan Fernandez Islands, Chile. Eight of the species are restricted to the older island (Masatierra, ca. 4 million years old), which is also closer to the mainland. Three species, one from each subgenus, are restricted to Masafuera, which is younger geologically (1–2 million years old) and 145 km further west of Masatierra. A total of 16 compounds was identified, with the 7-0-glucosides of the flavones apigenin and luteolin accounting for 12 of the constituents. Two glucosides of the flavonol quercetin were detected. Despite considerable interpopulation variation within species, six of the taxa have distinctive flavonoid profiles. Although there are few absolute differences among the subgenera, they can be distinguished chemically. Subgenus Rea contains the greatest number of compounds, and a previous cladistic analysis based on morphological features suggested this subgenus as most primitive. Subgenus Phoenicoseris is considered highly derived morphologically, and it has a reduced flavonoid chemistry. Very little reduction in flavonoid diversity was seen in the morphologically specialized subg. Dendroseris as compared to subg. Rea. A trend in reduction of numbers of compounds was seen for two of the three species on the younger island of Masafuera when compared to their presumed ancestors on Masatierra. Flavonoids of selected species of Hieracium and Hypochaeris, presumptive mainland progenitors of Dendroseris, reveal a close chemical affinity with the former genus.     

Comparative chromatography of Brazilian coral snake (Micrurus) venoms.

1. Elution profiles of 11 coral snake venoms, including those of Micrurus albicinctus, M. corallinus, M. frontalis altirostris, M. f. brasiliensis, M. f. frontalis, M. fulvius fulvius, M. ibiboboca, M. lemniscatus ssp., M. rondonianus, M. spixii spixii and M. surinamensis surinamensis, were compared using high performance gel filtration and reverse phase media. 2. Micrurus venom profiles were compared with those of "outgroup" taxa Bothrops moojeni, Naja naja kaouthia and Bungarus multicinctus. 3. Purified elapid venom constituents were also chromatographed under identical conditions in order to suggest possible identities of Micrurus venom constituents. 4. Masses of various components were confirmed by mass spectrometry. 5. Phospholipase constituents in three venoms were positively identified based on their reverse phase chromatograms. 6. Venoms of M. rondonianus and M. s. surinamensis are shown to be significantly different in their peptide composition from other Micrurus venoms.     

Partition of DDT in synthetic and native membranes

Partition of DDT (2,2-bis(p-chlorophenyl)-1,1,1-trichloroethane) was determined in artificial and native membranes. Partition in egg phosphatidylcholine of about 260 000 is independent of temperature over the range from 10 to 40 degrees C, in which the lipid is in the liquid-crystalline state. Incorporation of 50 mol% cholesterol decreases DDT partition to about 120 000. First-order phase transitions of dimyristoyl-, dipalmitoyl- and distearoylphosphatidylcholines (DMPC, DPPC and DSPC) are accompanied by a sharp increase in DDT partitioning. Partition decreases symmetrically in the temperature ranges to both sides of the phase transition. The insecticide is preferentially accommodated in bilayers of short-aliphatic-chain lipids, since the partitions were 336 000, 180 000 and 88 000 in DMPC, DPPC and DSPC, respectively, at temperatures 10 Cdeg below the midpoint of their transitions. Partition values in native membranes decrease sequentially as follows: sarcoplasmic reticulum, mitochondria, myelin, brain microsomes and erythrocytes. This sequence is similar to that observed in related liposomes of total extracted lipids, although the absolute partitions showed decreased values. Partition of DDT in native membranes exhibits a negative temperature coefficient not apparent in related lipid dispersions. The effect of intrinsic membrane cholesterol on partition of DDT was also investigated.     

Active and passive respiratory mechanics in anesthetized dogs

In six spontaneously breathing anesthetized dogs (pentobarbital sodium, 30 mg/kg) airflow, volume, and tracheal and esophageal pressures were measured. The active and passive mechanical properties of the total respiratory system, lung, and chest wall were calculated. The average passive values of respiratory system, lung, and chest wall elastances amounted to, respectively, 50.1, 32.3, and 17.7 cmH2O X l-1. Resistive pressure-vs.-flow relationships for the relaxed respiratory system, lung, and chest wall were also determined; a linear relationship was found for the former (the total passive intrinsic resistance averaged 4.1 cmH2O X l-1 X s), whereas power functions best described the others: the pulmonary pressure-flow relationship exhibited an upward concavity, which for the chest wall presented an upward convexity. The average active elastance and resistance of the respiratory system were, respectively, 64.0 cmH2O X l-1 and 5.4 cmH2O X l-1 X s. The greater active impedance reflects pressure losses due to force-length and force-velocity properties of the inspiratory muscles and those due to distortion of the respiratory system from its relaxed configuration.     

Antigenic relationships between Aracoccidioides loboi and other pathogenic fungi determined by immunofluorescence

Summary The fluorescent antibody technique was used to study antigenic relationships betweenParacoccidioides loboi and other pathogenic fungi. The findings suggest thatP. loboi is more closely related antigenically to certainP. brasiliensis strains than to others and that it has antigens in common with the yeast form ofHistoplasma capsulatum, H. duboisii, Blastomyces dermatitidis, Candida albicans and also the mycelial form ofCoccidioides immitis. Serum globulins from 3 cases of keloidal blastomycosis were labelled with fluorescein isothiocyanate. These conjugates showed slight or no reactivity withP. loboi, the yeast forms ofP. brasiliensis, H. capsulatum, H. duboisii andB. dermatitidis, However, they stained brightlyC. albicans, serotypes A and B, the tissue form ofC. immitis and the yeast form ofSporotrichum schenckii. Adsorption of these reagents withC. albicans eliminated all staining except that forS. schenckii. These patients had no history of clinical sporotrichosis.Deceased. Last address: Fundacão Gonçalo Moniz, Salvador, Bahia, Brazil. Requests for reprints should be sent to Dr.William Kaplan.Dr.Miranda is in private practice in Rio de Janeiro, Brazil.