Management of land/inland water ecotones: needs for regional approaches to achieve sustainable ecological systems

Evidence suggests that the boundaries between rivers, floodplain wetlands, and adjacent upland communities are among the most important components of landscapes. In a landscape context, floodplain wetlands and their ecotones are important transition zones between uplands and aquatic ecosystems. Management of wetland patches and ecotones to achieve sustainable ecosystems requires action on a broad scale, giving consideration to all factors affecting wetlands and the drainage basins of which they are a part. In northeastern United States, a struggle to identify new sources of water has focussed attention on the sustainability of aquatic ecosystems.     

Simplified methods for monitoring petroleum‐contaminated ground water and soil vapor

Portable meters and simplified gas Chromatographic (GC) techniques were investigated for monitoring volatile hydrocarbon (HC), CO₂, and O₂, concentrations in groundwater, exhaust gases, and soil vapor during in situ remediation using soil vapor extraction (SVE) and air sparging (AS). Results of groundwater samples analyzed in‐house using a headspace technique compared well to split samples analyzed by a certified analytical laboratory (r² = 0.94). SVE exhaust gas HC and CO₂ concentrations measured using a GT201 portable HC/O₂ meter and a RA‐411A meter (GasTech), respectively, were highly correlated with in‐house laboratory GC analyses (r² = 0.91). O₂ concentrations fell in a small range and meter analyses were not well correlated with laboratory analyses. Results of soil gas monitoring were not as well correlated as those for exhaust gases for HC, CO₂, or O₂, perhaps due to environmental conditions such as changes in relative humidity or the wider range of soil gas values. Overall, the meters were good indicators of vapor contamination, they greatly simplified estimates of total HC mass removal, and they allowed estimates of the biological contribution to contaminant removal during the remediation process.     

Effect of indomethacin on prostaglandin content of several rabbit tissues

The prostaglandin (PG) content of several tissues and fluids from 6 day pregnant rabbits was evaluated following treatment with indomethacin or vehicle . PGE and PGF were measured by radioimmunoassay. More complete depletion of PGE and PGF was accomplished by 3 injections of indomethacin (s.c.) given during the 18 h before sacrifice at a dose of 10 mg indomethacin per kg body weight than was accomplished by 1 injection of the same amount of indomethacin (i.v.) 1.5 h before sacrifice. Levels of PGF were more easily depressed by indomethacin than were those of PGE. PG levels in the kidney and blastocysts were depressed to a greater extent by indomethacin than were those in the uterus, uterine fluid or peritoneal fluid. Evaluation of the effect of indomethacin on a particular physiological function should be interpreted with caution unless the extent of PG depletion in that tissue is also measured.     

Effect of monensin on osmotic water flow across the toad bladder and its stimulation by vasopressin and cyclic AMP

Summary The effects of the sodium ionophore monensin on osmotic water flow across the urinary bladder of the toadBufo marinus were studied. Monensin alone did not alter osmotic water flow; however, the ionophore inhibited the hydrosmotic response to vasopressin and cyclic AMP in a dose-dependent manner. The inhibitory effects of monensin were apparent when the ionophore was added to the serosal bathing solution but not when it was added to the mucosal bathing solution. The inhibitory effect of serosal monensin required the presence of sodium in the serosal bathing solution but not the presence of calcium in the bathing solutions. Thus, it appears that intracellular sodium concentration is a regulator of the magnitude of the hydrosmotic response to vasopressin and cyclic AMP.     

Interactions of Folch-Lees proteolipid apoprotein with planar lipid bilayers

Summary Water-soluble Folch-Lees proteolipid apoprotein from bovine CNS white matter induces a voltage-dependent conductance in black lipid membranes. Na⁺ is required for the induced conductance change but the established conductance has very low ionic selectivity. The induced conductance fluctuates with a minimum amplitude of 10^–11–10^–10 mho. The magnitude of the conductivity change is dependent on protein concentration and on the composition of lipid bilayers. At a fixed voltage the induced conductance of a phosphatidylcholine-cholesterol membrane is proportional to the sixth power of the protein concentration and the first power of Na⁺ concentration. The interactions between the apoprotein and the lipids are both electrostatic and hydrophobic, but the interaction leading to the conductance increase appears to be mainly hydrophobic. Both the increase in conductance and the current fluctuations remain after extensive washing of the chambers to remove the protein. Furthermore, pronase or glutaraldehyde added to either the cis or trans side of the membrane does not affect the apoprotein-established conductance. However, if the bilayer is formed in the presence of both the apoprotein and pronase or if the apoprotein is treated with pronase prior to its addition to the chamber, no conductance change is observed. The association of the apoprotein with the membrane thus appears to render the protein inaccessible to proteolytic digestion, suggesting that the apoprotein is at least partially imbedded in the membrane interior.     

Direct cytological evidence for true terminalization of chiasmata in maize

Equational and disjunctional separation of heterozygous heterochromatic regions was observed relative to chiasma positions at diakinesis. Equational separation of heterozygous knobs was frequently observed and always accompanied by a chiasma distal to the knob. This is considered evidence that in these cases a crossover had occurred in a position proximal to the knob and had terminalized to a position distal to the knob by the time of fixation for observation.     

Genetics of Cortisone-Induced Cleft Palate in the Mouse—embryonic and Maternal Effects

Differences between mouse strains in frequency of embryonic, cortisone-induced cleft palate were examined. Probit analysis demonstrated a family of linear and parallel dose-response curves for different inbred and hybrid embryos. Since the differences between genotypes were not in the slopes of the response curves but rather in their location, it is proposed that the median effective dose (ED₅₀) of cortisone required to induce cleft palate (or the tolerance) provides a more appropriate definition of the response trait and its difference than a frequency statement. The tolerance of C57BL/6J is dominant to that of A/J. A maternal effect of A/J relative to C57BL/6J dams caused a two-fold reduction in the embryonic tolerance of cortisone. Cortisone-induced cleft palate and mortality were separate response traits.—In these and previous studies on cortisone- and other glucocorticoid-induced cleft palate in the mouse, the nature of the cleft-palate-response curve appeared to be the same for all glucocorticoids, and within-strain differences in tolerance could be used as measures of potency or bioassays for a particular effect of the glucocorticoids.     

Identification of an arsenic-sensitive block to primate lentiviral infection of human dendritic cells

Dendritic cells are central to the early events of human immunodeficiency virus type 1 (HIV-1) transmission, but HIV-1 infects dendritic cells inefficiently in vitro compared to activated CD4(+) T cells. There is a strong postentry restriction of HIV-1 infection in dendritic cells, partly mediated by the cellular restriction factor APOBEC3G. Here, we reveal that arsenic trioxide markedly increases HIV infection of immature and mature dendritic cells as well as blood-derived myeloid dendritic cells in an APOBEC3G- and TRIM5alpha-independent way. Our data suggest the presence of powerful, arsenic-sensitive antiviral activities in primary human immune cells of the dendritic cell lineage.