A retrospective study of disease and mortality in zebra finches

Few published reports exist describing morbidity and mortality in domestic zebra finch colonies maintained in a laboratory animal setting. A retrospective study of clinical disease and mortality in quarantined adult zebra finches was performed. Animals were observed during the 2 week quarantine period and for at least 1 month afterwards (42 days). Signs of disease, including feather and beak abnormalities, oculonasal discharge, increased respiratory rate or stridor, abdominal enlargement, pasty vent, diarrhea, lameness and pectoral muscle loss, were evaluated in our colony during this time. History, physical examination, laboratory testing and postmortem evaluation were used to determine causes of clinical disease. Common clinical findings in sick finches included sudden death, ruffled feathers, increased respiratory rate or gape mouthed breathing, pasty vent or frank diarrhea, and beak discoloration. Organisms frequently isolated were Staphylococcus spp., E. coli, Enterobacter spp., and Coccidia spp. Of the finches that died while in the colony (29.5%), 23.0% died in the first week after arrival. Pathogens frequently isolated from tissues cultured at necropsy included: E. coli, Staphylococcus aureus, Enterobacter spp., and Candida albicans. When observed, pathological lesions consisted of air sacculitis, fibrinopurulent polyserositis and ventriculitis.     

Uptake,Transport and Storage of Cardenolides in Foxglove. Cardenolide Sinks and Occurrence of Cardenolides in the Sieve Tubes of Digitalis lanata1

Cardiac glycoside transport was investigated on the organ and whole plant level. Uptake experiments were carried out with shoot and root cultures of Digitalis lanata. In both systems primary cardenolides, i.e., those with a terminal glucose in their oligosaccharide side chain, were taken up against their concentration gradient, whereas the glucose-free secondary cardenolides were not. Active uptake of primary cardenolides was further evidenced by KCN inhibition of uptake. Using plantlets grown in vitro the long-distance transport of primary cardenolides from the leaves to the roots was demonstrated. Cardenolides were also detected in etiolated leaves, induced on plants with green leaves, which are supposed to be unable to synthezise cardenolides de novo, providing further evidence for long-distance transport. Several primary cardenolides were detected in the honeydew excreted by aphids fed on Digitalis lanata leaves, indicating that the phloem is a transporting tissue for cardenolides. On the other hand, the xylem sap obtained by applying the pressure-chamber technique was cardenolide-free. It was concluded that in Digitalis primary cardenolides serve as both the transport and the storage form of cardenolides. After their synthesis they are either stored in the vacuoles of the source tissue or loaded into the sieve tubes, from which they are unloaded at other sites where they are trapped in the vacuoles of the respective sink tissue.     

Spontaneous curvature of fluid vesicles induced by trans-bilayer sugar asymmetry

We present measurements of the effective spontaneous curvature of fluid lipid bilayers as a function of trans-bilayer asymmetry. Experiments are performed on micrometer-scale vesicles in sugar solutions with varying species across the membrane. There are two effects leading to a preferred curvature of such a vesicle. The spontaneous curvatures of the two monolayers as well as their area difference combine into an effective spontaneous curvature of the membrane. Our technique for measuring this parameter allows us to use vesicle morphology as a probe for general membrane-solute interactions affecting elasticity. Received: 3 June 1998 / Revised version: 18 August 1998 / Accepted: 21 August 1998     

Integrative inference of gene-regulatory networks in Escherichia coli using information theoretic concepts and sequence analysis

Background  

Although Escherichia coli is one of the best studied model organisms, a comprehensive understanding of its gene regulation is not yet achieved. There exist many approaches to reconstruct regulatory interaction networks from gene expression experiments. Mutual information based approaches are most useful for large-scale network inference.     

Two types of heat tolerance in FHM-cells. Induction by heat-shock versus elevated culturing temperature

1. 1.Increased heat tolerance in FHM-cells from Pimephales promelas (Pisces) can be induced by culturing the cells at elevated temperatures (heat resistant acclimation) as well as by heat shock (heat hardening).

2. 2.After shift of culturing temperature (CT) from 16 to 32°C both effects are detectable with different temporal patterns.

3. 3.Cellular concentrations of heat-shock proteins correlate with the hardening effect but not with heat resistance acclimation.

4. 4.Several culturing temperature specific proteins were detected. The patterns of some enzymes are also altered by culturing temperature.

5. 5.Heat resistance acclimation is not caused by selection of a thermoresistant subpopulation of cells.

6. 6.Heat hardening and heat resistance acclimation must be distinguished as different phenomena in FHM-cells.

A simple, sensitive and reliable assay for serotonin and 5-HIAA in brain tissue using liquid chromatography with electrochemical detection

An extremely sensitive and simple method for simultaneously measuring both serotonin and 5-hydroxyindoleacetic acid (5-HIAA) has been developed using liquid chromatography (LC) and electrochemical detection. Assay conditions are described which resolve and measure as little as 22 picograms of serotonin and its deaminated metabolite in deproteinated brain samples.     

Carrier-independent entry of 1-methyl-4-phenylpyridinium (MPP+) into adrenal chromaffin cells as a consequence of charge delocalization

The administration of 1-methyl-4-phenylpyridinium (MPP+) to cultures of adrenal medullary chromaffin cells resulted in time and concentration-dependent increases in the cellular content of MPP+. Co-incubation of cells with MPP+, in the presence of desmethylimipramine (DMI), reduced but did not prevent the accumulation of the pyridinium in these cells. Similarly, DMI and MPP+ co-administration reduced but did not prevent the neurotoxicant-induced release of a cytosolic marker, lactate dehydrogenase, into the media. Molecular orbital calculations reveal that the positive charge of MPP+ is highly delocalized throughout the pyridinium ring and consequently MPP+ may be able to diffuse down concentration or charge gradients. Thus, these data provide a basis for the entry of MPP+ into cells and subcellular organelles that lack a catecholamine transporter, e.g. mitochondria.