Spatio‐temporal variation of salt marsh seedling establishment in relation to the abiotic and biotic environment

Contrary to our expectations, soil salinity and moisture explained little of the spatial variation in plant establishment in the upper intertidal marsh of three southern California wetlands, but did explain the timing of germination. Seedlings of 27 species were identified in 1996 and 1997. The seedlings were abundant (maximum densities of 2143/m² in 1996 and 1819/m² in 1997) and predominantly annual species. CCAs quantified the spatial variation in seedling density that could be explained by three groups of predictor variables: (1) perennial plant cover, elevation and soil texture (16% of variation), (2) wetland identity (14% of variation) and (3) surface soil salinity and moisture (2% of variation). Increasing the spatial scale of analysis changed the variables that best predicted patterns of species densities. Timing of germination depended on surface soil salinity and, to a lesser extent, soil moisture. Germination occurred after salinity had dropped below a threshold or, in some cases, after moisture had increased above a critical level. Between 32% and 92% of the seedlings were exotic and most of these occurred at lower soil salinity than native species. However, Parapholis incurva and Mesembryanthemum nodiflorum were found in the same environments as the native species. In 1997, the year of a strong El Niño/Southern Oscillation event with high rainfall and sea levels, the elevation distribution of species narrowed and densities of P. incurva and other exotic species decreased but densities of native and rare species did not change. The ‘regeneration niche’ of wetland plant communities includes the effects of multiple abiotic and biotic factors on both the spatial and temporal variations in plant establishment.     

Localization and characterization of neuropeptide Y-like peptides in the brain and islet organ of the anglerfish (Lophius americanus)

Summary Results from a previous report demonstrate that more than one molecular form of neuropeptide Y-like peptide may be present in the islet organ of the anglerfish (Lophius americanus). Most of the neuropeptide Y-like immunoreactive material was anglerfish peptide YG, which is expressed in a subset of islet cells, whereas an additional neuropeptide Y-like peptide(s) was localized in islet nerves. To learn more about the neuropeptide Y-like peptides in islet nerves, we have employed immunohistochemical and biochemical methods to compare peptides found in anglerfish islets and brain. Using antisera that selectively react with either mammalian forms of neuropeptide Y or with anglerfish peptide YG, subsets of neurons were found in the brain that labelled with only one or the other of the antisera. In separate sections, other neurons that were labelled with either antiserum exhibited similar morphologies. Peptides from brains and islets were subjected to gel filtration and reverse-phase high performance liquid chromatography. Radioimmunoassays employing either the neuropeptide Y or peptide YG antisera were used to examine chromatographic eluates. Immunoreactive peptides having retention times of human neuropeptide Y and porcine neuropeptide Y were identified in extracts of both brain and islets. This indicates that peptides structurally similar to both of these peptides from the neuropeptide Y-pancreatic polypeptide family are expressed in neurons of anglerfish brain and nerve fibers of anglerfish islets. The predominant form of neuropeptide Y-like peptide in islets was anglerfish peptide YG. Neuropeptide Y-immunoreactive peptides from islet extracts that had chromatographic retention times identical to human neuropeptide Y and porcine neuropeptide Y were present in much smaller quantities. These results are consistent with the hypothesis that peptides having significant sequence homology with human neuropeptide Y and porcine neuropeptide Y are present in the nerve fibers that permeate the islet.     

Synthesis and properties of azidonitrophenyl pyrophosphate, a photoaffinity probe of the nucleotide binding sites of mitochondrial F1-ATPase

4-Azido-2-nitrophenyl pyrophosphate (azido-PPi) labeled with 32P in the alpha position was prepared and used to photolabel beef heart mitochondrial F1. Azido-PPi was hydrolyzed by yeast inorganic pyrophosphatase, but not by mitochondrial F1-ATPase. Incubation of F1 with [alpha-32P]azido-PPi in the dark under conditions of saturation resulted in the binding of the photoprobe to three sites, two of which exhibited a high affinity (Kd = 2 microM), the third one having a lower affinity (Kd = 300 microM). Mg2+ was required for binding. As with PPi [Issartel et al. (1987) J. Biol. Chem. 262, 13538-13544], the binding of 3 mol of azido-PPi/mol of F1 resulted in the release of one tightly bound nucleotide. ADP, AMP-PNP, and PPi competed with azido-PPi for binding to F1, but Pi and the phosphate analogue azidonitrophenyl phosphate did not. The binding of [32P]Pi to F1 was enhanced at low concentrations of azido-PPi, as it was in the presence of low concentrations of PPi. Sulfite, which is thought to bind to an anion-binding site on F1, inhibited competitively the binding of both ADP and azido-PPi, suggesting that the postulated anion-binding site of F1 is related to the exchangeable nucleotide-binding sites. Upon photoirradiation of F1 in the presence of [alpha-32P]azido-PPi, the photoprobe became covalently bound with concomitant inactivation of F1. The plots relating the inactivation of F1 to the covalent binding of the probe were rectilinear up to 50% inactivation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Beta-adrenergic stimulation enhances translocation, processing and synthesis of lipoprotein lipase in rat heart cells

Cells isolated from newborn rat hearts were cultured for 10-14 days, and lipoprotein lipase activity was present in an intracellular and heparin-releasable pool. Treatment of the cultures with 10(-7) M isoproterenol for 3 min resulted in a 3-fold increase in heparin-releasable lipoprotein lipase and a concomitant decrease in residual cellular enzyme activity. Similar results were obtained by treatment with dibutyryl cAMP. Treatment with isoproterenol or dibutyryl cAMP for 2 h affected glycosylation of immunoadsorbable lipoprotein lipase, so that the ratio of [3H]galactose to [14C]mannose in the heparin-releasable enzyme increased from 3.8 (control) to 13.0 (isoproterenol-treated). The change in the ratio of the sugars in the cellular fraction of the enzyme was from 3.1 to 9.9. 2 h treatment with isoproterenol did not enhance new enzyme synthesis, as determined by incorporation of [3H]leucine into immunoadsorbable lipoprotein lipase. 24 h after addition of either isoproterenol or dibutyryl cAMP to the culture medium, stimulation of enzyme synthesis was demonstrated. The present results permit three effects of isoproterenol on lipoprotein lipase to be distinguished: stimulation of translocation from a cellular to heparin-releasable pool; enhanced processing of mannose residues and terminal glycosylation; stimulation of synthesis of enzyme protein.     

Effects of Chicken-excrement Amendments on Meloidogyne arenaria

The effects of chicken litter on Meloidogyne arenaria in tomato plants cv. Rutgers were determined in the greenhouse. Tomato seedlings were transplanted into a sandy soil amended with five rates of chicken litter and inoculated with 2,000 M. arenaria eggs. After 10 days, total numbers of nematodes in the roots decreased with increasing rates of chicken litter. After 46 days, egg numbers also decreased with increasing litter rates. In another experiment, soil was amended with two litter types, N-P-K fertilizer, and the two primary constituents of chicken litter (manure and pine-shaving bedding). After 10 days, numbers of nematodes in roots were smaller in chicken-excrement treatments as compared to nonexcrement treatments. At 46 days, there were fewer nematode eggs in chicken-excrement treatments compared to nonexcrement treatments. Egg numbers also were smaller for fertilizer and pine-shaving amendments as compared to nonamended controls. Chicken litter and manure amendments suppressed plant growth by 10 days after inoculation but enhanced root weights at 46 days after inoculation. Amendment of soil with chicken litter suppressed M. arenaria and may provide practical control of root-knot nematodes as part of an integrated management system.     

Postrhinoplasty "red nose": differential diagnosis and treatment by laser

Prior to anticipated nasal surgery, the nasal and facial skin should be examined for any vascular lesions. The skin type should be ascertained. A history of any prior nasal surgery, particularly on the nasal dorsum, should be noted. If rosacea is a clinical possibility, a trial of 1.5 to 2.0 gm q.d. of tetracycline for 6 to 8 weeks is warranted. If, after rhinoplasty, a diffuse "redness" on the nasal dorsum results and one can exclude other diagnoses, then argon laser therapy should be considered. A 3-mm punch biopsy should be obtained to see whether superficial ectatic vessels are present, a finding that would be indicative of a good result from laser therapy.     

Intraaortic administration of protamine: Method for heparin neutralization after cardiopulmonary bypass

In neutralizing heparin with intravenous protamine sulfate, hypotension may be prevented by administering the drug intraarterially. Forty patients underwent cardiac surgery with extracorporeal circulation in our hospital; each received a rapid injection of nondiluted protamine sulfate in the aortic root to reverse the effects of heparin. To maintain the blood volume at a constant level, volume expanders and inotropic drugs were avoided. The intraaortic injections ranged in duration from 0.2 min to 2.8 min, with a mean of 1.1 min. The mean systolic pressure only dropped from 92 mm Hg (SD +/- 21) before protamine injection to 85 mm Hg (SD +/- 23) after injection (p < 0.0001). In seven patients (18%), no hypotension was evident; in the remaining patients, the systolic pressure returned to preinjection values within a mean of 2.2 min. Coagulation was observed within 3 to 4 min (mean = 2.2 min) after the initiation of injection. This study indicates that intraaortic administration of protamine is a rapid and safe technique for heparin reversal after cardiopulmonary bypass.     

Kinetics of carboxymyoglobin and oxymyoglobin studied by picosecond spectroscopy.

Picosecond studies of carboxymyoglobin (MbCO) and oxymyoglobin (MbO2) reveal that excitation at 530 nm induces photodissociation at less than 8 ps. The kinetic and structural changes were monitored by following absorbance changes at selected wave-lengths in the Soret (B) band and in the Q band. Within the 10 ps-0.45 ns period of time over which our experiments were conducted, the absorbance changes in the Soret and Q bands for MbCO and MbO2 correspond to the conventional long-term, steady-state deoxymyoglobin difference spectra (Mb-MbCO and Mb-MbO2), as determined by comparison of isosbestic, maximum, and minimum points. In addition, MbCO exhibits a decay to a steady state in the Soret band (monitored at 440 nm). The onset of the decay immediately follows photodissociation and has a rate of (8 +/- 3) X 10(9) s-1 (tau = 125 +/- 50 ps). During the 10 ps-0.45 ns observation window, relaxation is not seen for MbO2 in the Soret band, nor is relaxation observed in the Q band for either MbCO or MbO2. We conclude from these results that the steady state that we observed for MbCO and MbO2 is most likely the stable form of deoxymyoglobin, and the relaxational differences between MbCO and MbO2 observed in the Soret band indicate that the electronic destabilization after ligand detachment is very different for these molecules. We believe that these relaxational differences may be related to differences in tertiary structural changes, or due to the fact that the MbCO (S = 0) molecule passes through an intermediate spin Mb (S = 1) state before relaxing the the Mb (S = 2) state.