Planetary science. Europa's ocean--the case strengthens

The possibility of a subsurface ocean on Jupiter's moon Europa has been suggested on the basis of theoretical, geological, and spectroscopic arguments. But, as Stevenson explains in his Perspective, none of these arguments were compelling. In contrast, the magnetic field data obtained by the Galileo spacecraft and presented in the report by Kivelson et al., provide persuasive evidence for a conducting layer--most likely a global water ocean--near Europa's surface.     

On the Presence of Fixed Ammonium in Rocks

From one-fourth to one-half of the nitrogen in some granite rocks, and up to two-thirds of that in some paleozoic shales, occurred as ammonium ions held within the lattice structure of silicate minerals. The results provide greater insight into the origin of the earth's atmosphere.     

Controlling the morphology of amorphous solid water

The morphology of amorphous solid water grown by vapor deposition was found to depend strongly on the angular distribution of the water molecules incident from the gas phase. Systematic variation of the incident angle during deposition using a collimated beam of water led to the growth of nonporous to highly porous amorphous solid water. The physical and chemical properties of amorphous solid water are of interest because of its presence in astrophysical environments. The ability to control its properties in the laboratory may shed light on some of the outstanding conflicts related to this important material.     

Effects of hen egg yolk immunoglobulin in passive protection of rainbow trout against Yersinia ruckeri

Anti-Yersinia ruckeri egg yolk immunoglobulin (IgY) was transferred to egg yolk after immunization of White Leghorn hens with formalin-killed whole cells of serovar 1 (RS1154) and serovar 2 (RS1153)Y. ruckeri and its lipopolysaccharide (LPS). The IgY was specific for its homologous LPS in western immunoblot, whereas some protein bands were commonly recognized, even by IgY from eggs of unimmunized hens. Purified LPS from both Y. ruckeri serovar types 1 and 2 had a very poor immunogenicity. The IgY activity was stable when processed into pellet form by a microbial transglutaminase treatment and showed a considerable resistance against acid pepsin for at least 2 h. Feeding specific anti-serovar 1 Y. ruckeri IgY to fish either before or after immersion infection produced marginal reductions in mortalities and in intestine infection. The same IgY did passively protect rainbow trout against infection when administered by intraperitoneal injection 4 h before an immersion challenge.     

Comparison of urine composition of healthy Labrador retrievers and miniature schnauzers.

OBJECTIVE: To compare urine composition in Labrador Retrievers (LR) and Miniature Schnauzers (MS) fed the same dog food. ANIMALS: 8 healthy LR (mean [+/- SD] age, 3.1+/-1.7 years) and 8 healthy MS (mean age, 3.7+/-1.3 years). PROCEDURE: A nutritionally complete dry dog food was fed to the dogs for 24 days. Urinary pH, volume, specific gravity, frequency of urination, and urinary concentrations of 12 analytes were measured for each dog; urinary relative supersaturation (RSS) with calcium oxalate and brushite (calcium hydrogen phosphate dihydrate) were calculated from these values. RESULTS: MS urinated significantly less often and had a lower urine volume (ml/kg of body weight per d) and a significantly higher urine pH, compared with LR. Urinary calcium concentration and brushite RSS were significantly higher in the urine of MS. As a result of a high calorie requirement, primarily as a result of high surface area to volume ratio, MS had significantly higher intake (per kg body weight) of dietary minerals, compared with LR. CONCLUSIONS AND CLINICAL RELEVANCE: Differences in urine composition exist between breeds fed the same diet, some of which, including lower urine volume, higher calcium concentration, and higher brushite RSS, may contribute to the high prevalence of calcium oxalate uroliths observed in MS. Differences between breeds should be considered when evaluating strategies for controlling calcium oxalate stone formation.     

Factors affecting the performance of granular insecticides applied to field beans

Factors influencing the performance of various granular formulations of disulfoton and phorate after foliar application to field beans were investigated by bioassay in controlled environment rooms. Frequent rainfall and high temperature increased activity considerably but humidity had little effect. With disulfoton formulation on pumice rather than fuller's earth, and toxicant concentrations of 7.5% rather than 10% increased toxicity, but effects of formulation were small with phorate. The influence of rainfall and formulation were confirmed in a field experiment. There was evidence for an initial fumigant effect, particularly for phorate, in both laboratory and field experiments. The detailed effects of the various factors at different intervals after applying the granules are discussed in relation to the physical properties of the insecticides and granular carriers. It is suggested that the possibilities of controlling performance by influencing release rates from granules are limited for chemicals such as phorate and disulfoton which are appreciably adsorbed by soil.     

The contribution of molecular biology to Mycobacteriumavium subspecies Paratuberculosis research

Molecular biology has contributed to our knowledge and understanding of the structure of Mycobacteriumavium subspecies paratuberculosis and has been particularly useful in determining those components that elicit immune responses in the host or discriminate M. avium paratuberculosis from other closely related environmental mycobacteria. As such, it has made a significant impact in the field of diagnosis, and has been instrumental in the development of specific and sensitive diagnostic tests. The next decade will see exciting new developments in paratuberculosis research as a consequence of substantial advances made in the construction of gene transfer systems in mycobacteria. These will provide opportunities for applying new strategies to determine the genetic basis for pathogenesis and the mechanisms of drug resistance and will offer new prospects for the rational design of efficient vaccines.