Effects of N-fertilizers,straw, and dry fallow on the nitrogen balance of a flooded soil planted with rice

Summary Nitrogen balance studies were made on rice (Oryza sativa) grown in flooded soil in pots. A low rate of fertilizer (5.64 mg N. kg⁻¹ soil) did not depress the N gain, but a high rate (99.72 mg N. kg⁻¹ soil) elminated the N gain. Soil N loss was negligible since¹⁵N applied as ammonium sulfate and thoroughly mixed with the soil was recovered from the soil-plant system after 3 crops. The observed N gain, therefore, was caused by N₂-fixation, not by a reduction of soil N loss. Straw enhanced N gain at the rate of 2–4 mg per g straw. However, this gain was not observed when soil N availability was high. Dry fallow between rice crops decreased the N gain.     

Predictors of success in hypertensives treated with biofeedback-assisted relaxation

This paper describes differences in response in seventeen patients with essential hypertension who participated in a treatment program consisting of electromyograph biofeedback assisted relaxation training. Responders were found to have higher treatment values of urinary and plasma cortisol, Trait Anxiety and forehead muscle tension compared to treatment failures. Responders also sustained greater decreases in plasma, and urinary cortisol after treatment. These data are discussed in light of the ability to predict which hypertensive patients may be most benefitted by a relaxation based treatment.We would like to thank Dr. Charles Spielberger for his permission to use the State-Trait Anxiety Inventory. We thank Michael Robinson for assistance with statistical analysis.     

Comparison of the chemical changes in the rhizosphere of the nickel hyperaccumulator Alyssum murale with the non-accumulator Raphanus sativus

Changes in pH and redox potential were studied in the rhizosphere soil of a nickel hyperaccumulator plant (Alyssum murale) and of a crop plant, radish (Raphanus sativus). Differences in rhizosphere pH and reducing activity were found between the lateral and the main roots of both species, but the pH changes in the rhizosphere were similar in both species. Changes in pH were associated with the relative uptakes of cations and anions; whether the concentrations of heavy metals in the growth medium did not have any effect on the rhizosphere pH. The source of nitrogen (ammonium or nitrate) was the major factor determining the pH of the rhizosphere of both species. The redox potential of the rhizosphere was influenced by both the N-source and the concentrations of heavy metals. When heavy metals were not present in the growth medium, and nitrate was the N-source, the reducing capacity of A. murale roots was enhanced. However, the reducing activity of A. murale was always smaller than that of radish. Therefore, the mechanism of metal solubilization by the hyperaccumulator plant does not involve either the reduction of pH in the rhizosphere or the release of reductants from roots. The acidification and reducing activity of the roots of A. murale was always smaller than that of R. sativus.     

Coastal intrusion of copepods: mechanisms and consequences on the population biology of Rhincalanus nasutus

In contrast to its usual habitat as a copepod that may occurin shelf or slope waters with low oxygen content between depthsfrom the surface to >2000 m, Rhincalanus nasutus was foundin a shallow (<60 m) embayment, the Arauco Gulf in Chile.Here, we document the complex life history of this copepod wheredid and ontogenetic vertical migratory behavior was co-ordinatedwith the circulation pattern which helped to retain a summerresident population in the vicinity of the gulf. With the onsetof the upwelling season in the southern summer, the mid-depthEquatorial Sub Surface Waters intrude into the gulf, leadingto the formation of a strong thermocline at 10–20 m andthe development of a two-layer circulation pattern. CopepoditesI, C.II and C.III (first stage to exhibit migratory behavior)were found within the gulf in the layer where the net transportwas at a minimum while chlorophyll-a concentrations were ata maximum. Older stages (C.IV-C.VI females and males) migratefrom their daytime depth in the bottom, shoreward-moving, low-oxygenlayer, to their night-time depth in the shallow seaward-movinglayer. The population of copepods retained in the area thuslyreproduce, as reflected in the sequential pulses of differentdevelopmental stages. Because coastal intrusions such as thisof R.nasutus have been documented for several other speciesduring the seasons of maximum phytoplankton production (upwelling),they may form part of a more widespread reproductive strategyof the larger zooplankton of coastal upwelling systems thanpreviously suspected.     

Use of olive mill wastewater compost for crop production

Vast amounts of olive mill wastewaters (OMW) are produced in Mediterranean countries, where their treatment and disposal are becoming a serious environmental problem. Increasing attention has been paid to discovering a use for OMW and a wide range of technological treatments are available nowadays for reducing their pollutant effects and for their transformation into valuable products, the most suitable procedures being found to involve recycling rather than the detoxication of these wastes. Direct application of OMW to soil has been considered as an inexpensive method of disposal and recovery of their mineral and organic components but, because of their organic acid and phenol contents, OMW are also a source of pollution. By using composting technologies, it is possible to transform either fresh OMW or sludge from pond-stored OMW mixed with appropriate plant waste waterials (carriers) into organic fertilizers (composts) with no phytotoxicity to improve soil fertility and plant production, the process involving the microbial degradation of the polluting load of the wastes. Results of field and pot experiments using OMW-composts to cultivate horticultural and other crops have shown that yields obtained with organic fertilization are similar, and sometimes higher, to those obtained with a balanced mineral fertilizer. A comparison between the macro and micronutrient contents of plants cultivated with organic or mineral fertilizers did not generally reveal important differences. However, the cases of iron and manganese are worth mentioning as their bio-availability may be linked to the soil humic complexes originated by the OMW organic fertilizers.     

Pseudomonas aeruginosa acid phosphatase and cholinesterase induced by choline and its metabolic derivatives may contain a similar anionic peripheral site

Summary Different compounds derived from choline, and obtained by demethylation or by oxidation of the primary alcohol group with subsequent N-demethylation, were tested as inducer agents of acid phosphatase and cholinesterase in Ps. aeruginosa. It was found that betaine and dimethylglycine were the most effective inducers of both enzyme activities. These metabolites including choline itself, were not inducers of acid phosphatase and cholinesterase in other Gram-negative bacteria such as: Escherichia coli, Salmonella typhimurium, Shigella flexneri, Enterobacter liquefacciens and Proteus mirabilis. The acid phosphatase activities found in these bacteria were not inhibited in vitro by choline, betaine and phosphorylcholine. From these results it may be concluded that the acid phosphatase activity from Ps. aeruginosa is different from the same activity observed in the other bacteria. In addition, it is also shown that Ps. aeruginosa acid phosphatase and cholinesterase were inhibited by a number of compounds containing a positively charged amino group, with methyl or ethyl groups bound to it. These results seem to confirm that Ps. aeruginosa acid phosphatase and cholinesterase may contain a similar anionic site.     

Nitrogen fixation throughout growth,and varietal differences in nitrogen fixation by the rhizosphere of rice planted in pots

Summary The nitrogen-fixing activity in the rhizospheres of various rices was measured by the acetylene-reduction method throughout plant growth in green-house pots. The activity began to increase 4 weeks after transplanting, increased until heading stage, then decreased. The concentrations of exchangeable ammonium and sugars in the soil were not related to the variation of nitrogen-fixing activity during rice growth.The nitrogen-fixing activities in the rhizospheres of 41 rice varieties in pots were measured to discover varietal differences. Levels of nitrogen fixation were highly correlated with the rices' dry root weight at heading stage.     

Pure red cell hypoplasia associated with long-arm deletion of chromosome 5

Summary A further instance of the new hematologic entity of pure red cell hypoplasia with deletion of the long arm of a chromosome 5(5q-) was seen in a 59-year-old white male. Examination of the bone marrow showed depressed erythroid cells with normal granulocytic and megakaryocytic precursors. Chromosomal analysis showed deletion of a chromosome 5 without any apparent translocation. This karyotype may be associated with acute leukemia.     

Hydrological extremes modulate nutrient dynamics in mediterranean climate streams across different spatial scales

We studied benthic macroinvertebrate communities upstream and downstream of five small reservoirs (surface release in autumn–winters) (north Spain) to assess the effect of flow regulation on structural and functional characteristics of stream ecosystems. We based our approach on the use of structural metrics (density, biomass, richness and diversity) in combination with two functional diversity indices based on biological and ecological traits: FD_PG index, related to species richness, and FD_Q, which incorporates evenness across taxa. Although water physicochemical parameters were unaffected by the reservoirs during the study period (autumn–winter), macroinvertebrate metrics were lower below the dams, with detritivores (shredders and collector-gatherers) being the most affected. The alder leaf breakdown rate estimated by the litter-bag technique was related to the density, biomass, richness, diversity and FD_PG index of shredders, compromising the ecosystem functioning. The most plausible origin for the observed differences in macroinvertebrate metrics between upstream and downstream reaches was the change of the flow regime caused by the impoundments at downstream sites, leading to droughts in summer in those naturally permanently flowing streams. The observed functional diversity loss might reduce the chances of the community to override natural or man-induced fluctuations in their environment with possible repercussions on important ecosystem functions and services.     

Analysis of temperature‐mediated changes in the wine yeast Saccharomyces bayanus var uvarum. An oenological study of how the protein content influences wine quality

Saccharomyces bayanus var. uvarum plays an important role in the fermentation of red wine from the D.O. Ribera del Duero. This is due to the special organoleptic taste that this yeast gives the wines and their ability to ferment at low temperature. To determine the molecular factors involved in the fermentation process at low temperature, a differential proteomic approach was performed by using 2D‐DIGE, comparing, qualitatively and quantitatively, the profiles obtained at 13 and 25°C. A total of 152 protein spots were identified. We detected proteins upregulated at 13°C that were shown to be related to temperature stress, the production of aromatic compounds involved in the metabolism of amino acids, and the production of fusel alcohols and their derivatives, each of which is directly related to the quality of the wines. To check the temperature effects, an aromatic analysis by GC–MS was performed. The proteomic and “aromatomic” results are discussed in relation to the oenological properties of S. bayanus var. uvarum.