Background yield of phosphorus from drainage area and atmosphere: An empirical approach

The role of phosphorus in the eutrophication of lakes and marine coastal areas has created a need of more information on the size of a virgin background supply of phosphorus.The general pollution of the atmosphere has resulted in an increased amount of anthropogenic phosphorus in air masses over remote ocean areas in the Northern Hemisphere. As a consequence this applies also to remote land areas, where the phosphorus deposition of about 5 kg P km^-2 a^-1 may seem to be 2–3 times the virgin phosphorus deposition.The present background drainage basin yield of phosphorus is also elevated due to a general eutrophication of the terrestrial ecosystem. The background supply varies due to several factors of which drainage basin size, geology and vegetation are discussed. Background yields apparently have a range from 3–10 kg P km^-2 a^-1.     

Sensitivity of Pseudomonas aeruginosa to Normal Serum and to Polymyxin

Strains of Pseudomonas aeruginosa isolated from clinical material were very variable in their sensitivity to the bactericidal action of normal serum mediated by the complement system. Fifty per cent killing end points ranged from 0.015 ml to greater than 0.4 ml. Most of the strains with relatively greater sensitivity to serum were isolated from patients with cystic fibrosis. Immunization of rabbits resulted in antisera with enhanced levels of bactericidal antibody, except with one strain which was resistant to the bactericidal action of normal serum and antiserum. When P. aeruginosa was cultivated at 41 C instead of at 37 C, it was significantly more sensitive to serum and to several antibiotics, thereby implicating fever as a host defense mechanism in Pseudomonas infections. In contrast to their heterogeneity to serum bactericidal activity, the strains were relatively homogeneous in their sensitivity to polymyxin, with no apparent association between their sensitivity to the two antimicrobial agents.     

Accumulation of scopoletin is associated with the high disease resistance of the hybrid Nicotiana glutinosa x Nicotiana debneyi

The high disease resistance of the amphidiploid hybrid of Nicotiana glutinosa x Nicotiana debneyi is associated with high constitutive levels of two phenolic compounds as analysed by high-performance liquid chromatography. The structures of these two compounds were elucidated by means of gas chromatography-tandem mass spectrometry, fluorescence- and light-spectrophotometry to be those of scopolin and scopoletin. They reached levels of 4 nmol·(g FW)^?1 and 35 nmol·(g FW)^?1, respectively, in leaf tissues of the hybrid, about 10–50 times the amount found in the parental species. Scopoletin showed a direct antimicrobial activity against Cercospora nicotianae, Phytophthora parasitica var. nicotianae, Pseudomonas syringae pvs. tabaci and syringae and tobacco mosaic virus when added to synthetic growth media, mixed with the inoculum or sprayed onto tobacco plants prior to inoculation. We postulate that the high amount of toxic phenolics in the leaves of the hybrid N. glutinosa x N. debneyi contributes to its high disease resistance.     

Grazing of nonindigenous bacteria by nano-sized protozoa in a natural coastal system

Mesocosms (4.5 m³) situated in a closed bay area were used to investigate the effect of protozoan predation on nonindigenous bacteria. Pseudomonas fluorescens strain Agl was released into mesocosms as a single inoculum of 1 × 10⁵ cells ml^–1 (final concentration) or as four inocula (same concentration each) at intervals of 3 days. Mesocosms that had received growth media corresponding to the inoculum served as controls. Numbers of P. fluorescens Ag1 decreased rapidly whether released as single or multiple inocula. Direct estimation of protozoan predation using fluorescently labeled P. fluorescens from log phase and starved cultures, respectively, revealed that natural populations of heterotrophic nanoflagellates consumed substantial amounts of the nonindigenous bacterial strain. The volume of fluorescently labeled cells prepared from starved cells was 68% of log phase cell volume, but the individual clearance of the small cells was five to seven times higher than that of the log phase bacteria. The natural populations of nanoflagellates consumed 34–62% of P. fluorescens Ag1 daily if starved bacteria were offered as food, and 3–13% if the cells were in the logarithmic growth phase. This suggests that the effect of protozoan predation on nonindigenous bacterial strains is substantial because cultured bacteria are likely to starve in natural environments. The addition of P. fluorescens Ag1 and the growth medium enhanced the abundance of natural bacteria, chlorophyll a, heterotrophic nanoflagellates, and ciliates, but it did not improve the growth conditions for the released strain. The effects on the indigenous populations were more pronounced after addition of fresh medium than following inoculation with cells, which possibly was due to the lower nutrient content of spent medium. However, these results, based on direct estimation of protozoan predation on log phase and starved nonindigenous bacteria, point to the conclusion that mortality induced by bacterivorous predators is the key factor determining removal of nonindigenous bacteria introduced in natural aquatic systems. Correspondence to: K. Christoffersen.     

QSAR modeling and transmission electron microscopy stereology of altered mitochondrial ultrastructure of white blood cells in patients diagnosed as schizophrenic and treated with antipsychotic drugs.

Treatment of patients diagnosed as schizophrenic with antipsychotic drugs (neuroleptics) is known to cause occasional unexplained depletion of white blood cells, especially neutrophil granulocytes. It has been known for many years that neuroleptics can interfere with the mitochondrial respiratory chain in vitro. Because there has been a growing interest recently in mitochondrial targeting of drugs, and since a quantitative structure-activity relationship (QSAR) model that predicts mitochondrial accumulation of neuroleptics has been published, we investigated the effects of neuroleptics on white blood cell mitochondria. Venous blood samples were collected from both patients undergoing treatment with neuroleptics and healthy volunteers. The samples were processed for transmission electron microscopy. The resulting images of white blood cells were analyzed using stereology to compare quantitatively mitochondrial morphology in the patient and control groups. We found that in patients, but not in controls, there was swelling of mitochondria and fragmentation of the mitochondrial cristae. There also were fewer mitochondria in patients than in controls, although due to the swelling of the organelles, the volume density of mitochondria in the two groups was not significantly different. Such changes are typical of a toxic insult. Consequently, it seems plausible that, since schizophrenia is not a disease considered to affect white blood cells per se, these changes probably are due to the medication.     

Dynamics of intracellular mannan and cell wall folding in the drought responses of succulent Aloe species

Plants have evolved a multitude of adaptations to survive extreme conditions. Succulent plants have the capacity to tolerate periodically dry environments, due to their ability to retain water in a specialized tissue, termed hydrenchyma. Cell wall polysaccharides are important components of water storage in hydrenchyma cells. However, the role of the cell wall and its polysaccharide composition in relation to drought resistance of succulent plants are unknown. We investigate the drought response of leaf‐succulent Aloe (Asphodelaceae) species using a combination of histological microscopy, quantification of water content, and comprehensive microarray polymer profiling. We observed a previously unreported mode of polysaccharide and cell wall structural dynamics triggered by water shortage. Microscopical analysis of the hydrenchyma cell walls revealed highly regular folding patterns indicative of predetermined cell wall mechanics in the remobilization of stored water and the possible role of homogalacturonan in this process. The in situ distribution of mannans in distinct intracellular compartments during drought, for storage, and apparent upregulation of pectins, imparting flexibility to the cell wall, facilitate elaborate cell wall folding during drought stress. We conclude that cell wall polysaccharide composition plays an important role in water storage and drought response in Aloe.     

Improvement in multiple dimensions of fatigue in patients with fibromyalgia treated with duloxetine: secondary analysis of a randomized,placebo-controlled trial

Introduction  

Fatigue is one of the most disabling symptoms associated with fibromyalgia that greatly impacts quality of life. Fatigue was assessed as a secondary objective in a 2-phase, 24-week study in outpatients with American College of Rheumatology-defined fibromyalgia.     

Dynamics in the cyclic Enterobacterial common antigen as studied by <Superscript>13</Superscript>C NMR relaxation

The motional properties of the cyclic enterobacterial common antigen (cECA), consisting of four trisaccharide repeat units, have been investigated by carbon-13 spin relaxation. R₁, R₂ and NOE relaxation parameters have been determined at three magnetic field strengths. The data were interpreted within the model-free framework to include the possibility of motional anisotropy, and overall as well as local dynamical parameters were fitted separately for each ring carbon. The motional anisotropy was addressed by assuming an axially symmetric diffusion tensor, which was fitted from the overall correlation times for each site in the sugar residues using the previously determined crystal structure. The data were found to be in agreement with an oblate shape of the molecule, and the values for D_iso and were in good agreement with translational diffusion data and an estimate based on calculation of the moment of inertia tensor, respectively. The local dynamics in cECA were found to be residue-dependent. Somewhat lower values for the order parameters, as well as longer local correlation times, were observed for the -linked ManNAcA residue compared to the two -linked residues in the trisaccharide repeat unit.     

QSAR modeling and transmission electron microscopy stereology of altered mitochondrial ultrastructure of white blood cells in patients diagnosed as schizophrenic and treated with antipsychotic drugs.

Treatment of patients diagnosed as schizophrenic with antipsychotic drugs (neuroleptics) is known to cause occasional unexplained depletion of white blood cells, especially neutrophil granulocytes. It has been known for many years that neuroleptics can interfere with the mitochondrial respiratory chain in vitro. Because there has been a growing interest recently in mitochondrial targeting of drugs, and since a quantitative structure-activity relationship (QSAR) model that predicts mitochondrial accumulation of neuroleptics has been published, we investigated the effects of neuroleptics on white blood cell mitochondria. Venous blood samples were collected from both patients undergoing treatment with neuroleptics and healthy volunteers. The samples were processed for transmission electron microscopy. The resulting images of white blood cells were analyzed using stereology to compare quantitatively mitochondrial morphology in the patient and control groups. We found that in patients, but not in controls, there was swelling of mitochondria and fragmentation of the mitochondrial cristae. There also were fewer mitochondria in patients than in controls, although due to the swelling of the organelles, the volume density of mitochondria in the two groups was not significantly different. Such changes are typical of a toxic insult. Consequently, it seems plausible that, since schizophrenia is not a disease considered to affect white blood cells per se, these changes probably are due to the medication.