Modified microassay for the isolation of antimicrobial-producing, spore-forming and nonspore-forming bacteria.

AIMS: To develop a microassay method to detect antimicrobials produced by spore-forming bacteria, thus speeding up the discovery of new antimicrobials. METHODS AND RESULTS: Environmental isolates were grown in 96-well plates, to allow production of antimicrobial agents, then treated with lysozyme and heated sequentially. Lysozyme heat treatment inhibited or prevented spore-to-cell transformation, thus eliminating interference from spore outgrowth while detecting antimicrobials by indicator bacteria. Supplementation of the indicator strain medium with 2,3,5-triphenyltetrazolium chloride, as a vital stain, made it easy to rapidly differentiate between antimicrobial-deficient (indicator growth) and antimicrobial-containing (no growth) wells. The method was used to rapidly screen 657 bacteria isolated from eight soil samples. Results revealed 46 Bacillus sp. producing antimicrobials against Listeria sp., and a Bacillus sp. producing antimicrobial(s) against Escherichia coli. CONCLUSIONS: A microassay method was successfully developed and implemented to screen and detect antimicrobial agents from spore-forming, in addition to nonspore-forming, bacteria. SIGNIFICANCE AND IMPACT OF THE STUDY: Antimicrobials are needed to combat antibiotic- and preservative-resistant bacteria. Spore-forming bacteria are prolific producers of antimicrobials. This assay will speed the discovery of antimicrobials from spore-forming bacteria; these new antimicrobials are urgently needed in food and medicinal applications.

Comparison of Surfactant Distributions in Pressure-Sensitive Adhesive Films Dried from Dispersion under Lab-Scale and Industrial Drying Conditions.

Film-forming latex dispersions are an important class of material systems for a variety of applications, for example, pressure-sensitive adhesives, which are used for the manufacturing of adhesive tapes and labels. The mechanisms occurring during drying have been under intense investigations in a number of literature works. Of special interest is the distribution of surfactants during the film formation. However, most of the studies are performed at experimental conditions very different from those usually encountered in industrial processes. This leaves the impact of the drying conditions and the resulting influence on the film properties unclear. In this work, two different 2-ethylhexyl-acrylate (EHA)-based adhesives with varying characteristics regarding glass transition temperature, surfactants, and particle size distribution were investigated on two different substrates. The drying conditions, defined by film temperature and mass transfer in the gas phase, were varied to emulate typical conditions encountered in the laboratory and industrial processes. Extreme conditions equivalent to air temperatures up to 250 °C in a belt dryer and drying rates of 12 g/(m(2)·s) were realized. The surfactant distributions were measured by means of 3D confocal Raman spectroscopy in the dry film. The surfactant distributions were found to differ significantly with drying conditions at moderate film temperatures. At elevated film temperatures the surfactant distributions are independent of the investigated gas side transport coefficients: the heat and mass transfer coefficient. Coating on substrates with significantly different surface energies has a large impact on surfactant concentration gradients, as the equilibrium between surface and bulk concentration changes. Dispersions with higher colloidal stability showed more homogeneous lateral surfactant distributions. These results indicate that the choice of the drying conditions, colloidal stability, and substrates is crucial to control the surfactant distribution. Results obtained under lab-scale drying conditions cannot be transferred directly to the industrial application. The results were similar for both tested adhesive material systems, despite their different properties. This indicates that other properties, such as the particle size distribution and glass transition temperature, have surprisingly little effect on the development of the surfactant distribution.

Rare disasters and risk attitudes: international differences and implications for integrated assessment modeling.

Evaluation of public policies with uncertain economic outcomes should consider society's preferences regarding risk. However, the preference models used in most integrated assessment models, including those commonly used to inform climate policy, do not adequately characterize the risk attitudes revealed by typical investment decisions. Here, we adopt an empirical approach to risk preference description using international historical data on investment returns and the occurrence of rare economic disasters. We improve on earlier analyses by employing a hierarchical Bayesian inference procedure that allows for nation-specific estimates of both disaster probabilities and preference parameters. This provides a stronger test of the underlying investment model than provided by previous calibrations and generates some compelling hypotheses for further study. Specifically, results suggest that society is substantially more averse to risk than typically assumed in integrated assessment models. In addition, there appear to be systematic differences in risk preferences among nations. These results are likely to have important implications for policy recommendations: higher aversion to risk increases the precautionary value of taking action to avoid low-probability, high-impact outcomes. However, geographically variable attitudes toward risk indicate that this precautionary value could vary widely across nations, thereby potentially complicating the negotiation of transboundary agreements focused on risk reduction.

The enhanced contractility of the phospholamban-deficient mouse heart persists with aging.

J. P. Slack, I. L. Grupp, R. Dash, D. Holder, A. Schmidt, M. J. Gerst, T. Tamura, C. Tilgmann, P. F. James, R. Johnson, A. M. Gerdes and E. G. Kranias. The Enhanced Contractility of the Phospholamban-deficient Mouse Heart Persists with Aging. Journal of Molecular and Cellular Cardiology (2001) 33, 1031-1040. Phospholamban ablation in the mouse is associated with significant increases in cardiac contractility. To determine whether this hyperdynamic function persists through the aging process, a longitudinal examination of age-matched phospholamban-deficient and wild-type mice was employed. Kaplan-Meier survival curves indicated no significant differences between phospholamban-deficient and wild-type mice over the first year. Examination of cardiac function revealed significant increases in the rates of contraction (+dP/dt) and relaxation (-dP/dt) in phospholamban-deficient hearts compared with their wild-type counterparts at 3, 6, 12, 18 and 24 months of age. Quantitative immunoblotting indicated that the expression levels of the sarcoplasmic reticulum Ca(2+)-ATPase were not altered in wild-type hearts, while they were significantly decreased at 12 months (40%) and 18 months (20%) in phospholamban-deficient hearts. These findings on the persistence of hyperdynamic cardiac function over the long term suggest that phospholamban may constitute an important target for treatment in heart disease.

Interactions between phospholamban and beta-adrenergic drive may lead to cardiomyopathy and early mortality.

BACKGROUND: Relieving the inhibition of sarcoplasmic reticular function by phospholamban is a major target of beta-adrenergic stimulation. Chronic beta-adrenergic receptor activity has been suggested to be detrimental, on the basis of transgenic overexpression of the receptor or its signaling effectors. However, it is not known whether physiological levels of sympathetic tone, in the absence of preexisting heart failure, are similarly detrimental. METHODS AND RESULTS: Transgenic mice overexpressing phospholamban at 4-fold normal levels were generated, and at 3 months, they exhibited mildly depressed ventricular contractility without heart failure. As expected, transgenic cardiomyocyte mechanics and calcium kinetics were depressed, but isoproterenol reversed the inhibitory effects of phospholamban on these parameters. In vivo cardiac function was substantially depressed by propranolol administration, suggesting enhanced sympathetic tone. Indeed, plasma norepinephrine levels and the phosphorylation status of phospholamban were elevated, reflecting increased adrenergic drive in transgenic hearts. On aging, the chronic enhancement of adrenergic tone was associated with a desensitization of adenylyl cyclase (which intensified the inhibitory effects of phospholamban), the development of overt heart failure, and a premature mortality. CONCLUSIONS: The unique interaction between phospholamban and increased adrenergic drive, elucidated herein, provides the first evidence that compensatory increases in catecholamine stimulation can, even in the absence of preexisting heart failure, be a primary causative factor in the development of cardiomyopathy and early mortality.

Association analysis between bilateral convergent strabismus with exophthalmus and milk production traits in dairy cattle.

Bilateral convergent strabismus with exophthalmus (BCSE) is characterized in cattle by a symmetrical antero-medial rotation and protrusion of the eyeballs. This eye defect is caused by an inherited, centrally insufficient function of the eye muscles recti laterales and retractores. In German Brown cattle a monogenic, autosomal dominant inheritance proved to be most probable in complex segregation analysis. In our study running between October 1993 and May 1995 a total of 200 affected German Brown cows was studied. The investigation of the association between milk production traits and BCSE was based on 10,960 German Brown cows. The analysis revealed no significant differences between affected and non-affected cows, nor between cow families with and without affected members. There was no indication of an association between milk production traits and occurrence of BCSE within cow families. Linkage or pleiotropy of the BCSE locus with quantitative trait loci for milk production traits may be rather unlikely.

Life event reports by psychiatric patients, nonpatients, and their partners.

The Schedule of Recent Experience (SRE) was completed for three separate two-month periods by groups of male psychiatric patients, male nonpatients, and their partners (primarily spouses). Each partner completed the SRE for life events believed to have occurred to the index person. For both patient and nonpatient pairs, perfect agreement was reported for only about one third of the responses where at least one pair member reported an occurrence. With disagreements, index persons were little more likely than their partners to report that an event occurred. Agreement was higher for clearly worded than for vaguely worded items in both patient and nonpatient groups. Among nonpatient pairs only, agreement was higher for events that would be difficult to hide from a partner than for those that could be kept hidden. Agreement for undesirable events for either group.

Quality of life events in relation to psychiatric symptoms.

This prospective study explored the relationship of life changes to psychiatric symptom changes in psychiatric outpatients (N = 196) and a comparison group of nonpatients (N = 194). Subjects completed the Schedule of Recent Experiences and a symptom checklist bimonthly for 18 months. At all reporting intervals, symptoms and events were strongly correlated. Undesirable and uncontrollable events related positively and desirable events negatively to symptoms. Among symptoms, those of a dysphoric and somatic nature were most strongly associated with event change. Psychiatric patients also reported more undesirable, more uncontrollable, and fewer desirable events than the comparison group. We conclude that the relationship of life events to symptoms depends on the specific qualities of both events and symptoms. Undesirable and uncontrollable events appear to have a direct, and desirable events an inverse, association with dysphoric and somatic symptoms.

Sleep disorder over time: psychiatric correlates among males.

This 18 month prospective study assessed the time course of sleep disturbances in 85 male psychiatric out-patients and 103 male non-patients. Over one-third of the patients and 5 per cent of the non-patients reported frequent symptoms of insomnia during at least 14 of the 18 months. Frequency and chronicity of insomnia were strongly associated with intensity of psychiatric symptomatology, but not with diagnosis. Minor tranquillizers and hypnotics were used frequently by patients and occasionally by non-patients, but there was little indication that they altered the course of insomnia.

Sleep disorder and psychobiological symptomatology in male psychiatric outpatients and male nonpatients.

Sleep disturbance was studied in relation to psychiatric and physical symptoms for 214 male psychiatric outpatients and 248 male nonpatients. Our self-report instrument required that subjects describe the frequency of symptoms precisely on a five-point scale from "every day" to "not at all." Percentages are based on the numbers of subjects reporting a symptom as occurring "every day" or "several times a week." More patients reported sleep disturbance symptoms (75%) than nonpatients (25%) (P less than 0.001). Sleep loss symptoms were reported by 63% of patients and 20% of nonpatients. Twelve percent of patients and 6% of nonpatients reported trouble with excessive sleep problems. Sleep disturbance was not strongly related to specific diagnoses. Fewer schizophrenics (21%) than other patients (50%) reported trouble "falling asleep" (P less than 0.02). Finally, for both patients and controls, disturbed sleepers reported more psychiatric and physical symptoms than undisturbed sleepers (P less than 0.001). It is suggested that sleep disturbance might be a useful clinical clue to previously unsuspected psychiatric and physical illness.