Selection in Cladocera on the basis of a physiological character

Ohne Zusammenfassung

---

Selection in Cladocera on the basis of a physiological character

     

No Fabry Disease in Patients Presenting with Isolated Small Fiber Neuropathy

Objective

Screening for Fabry disease in patients with small fiber neuropathy has been suggested, especially since Fabry disease is potentially treatable. However, the diagnostic yield of testing for Fabry disease in isolated small fiber neuropathy patients has never been systematically investigated. Our aim is to determine the presence of Fabry disease in patients with small fiber neuropathy.

Methods

Patients referred to our institute, who met the criteria for isolated small fiber neuropathy were tested for Fabry disease by measurement of alpha-Galactosidase A activity in blood, lysosomal globotriaosylsphingosine in urine and analysis on possible GLA gene mutations.

Results

725 patients diagnosed with small fiber neuropathy were screened for Fabry disease. No skin abnormalities were seen except for redness of the hands or feet in 30.9% of the patients. Alfa-Galactosidase A activity was tested in all 725 patients and showed diminished activity in eight patients. Lysosomal globotriaosylsphingosine was examined in 509 patients and was normal in all tested individuals. Screening of GLA for mutations was performed for 440 patients, including those with diminished α-Galactosidase A activity. Thirteen patients showed a GLA gene variant. One likely pathogenic variant was found in a female patient. The diagnosis Fabry disease could not be confirmed over time in this patient. Eventually none of the patients were diagnosed with Fabry disease.

Conclusions

In patients with isolated small fiber neuropathy, and no other signs compatible with Fabry disease, the diagnostic yield of testing for Fabry disease is extremely low. Testing for Fabry disease should be considered only in cases with additional characteristics, such as childhood onset, cardiovascular disease, renal failure, or typical skin lesions.     

Glutathione and Ascorbate During Ischemia and Postischemic Reperfusion in Rat Brain

Thirty minutes of total cerebral ischemia (decapitation) decreased total glutathione (GSH + GSSG) by 7% but had no detectable effect on the concentration of oxidized glutathione (GSSG), reduced ascorbate, or total ascorbate. In a model of reversible, bilateral hemispheric ischemia (four-vessel occlusion) no changes in glutathione or ascorbate were detected after 30 min of ischemia. During 24 h of reperfusion following such an insult no detectable change in total ascorbate, reduced ascorbate, or oxidized glutathione was noted; however, total brain glutathione declined by 25%. The findings are discussed in relation to the hypothesis that the deleterious effects of ischemia are due to an increase in free radical production which in turn leads to increased lipid peroxidation.     

The social lifestyle of myxobacteria

Myxobacteria are social organisms that usually remain together even though they are not chemically attached to each other. They cooperatively feed and form aggregates and fruiting bodies. Their mode of movement, the forces and mechanisms that allow movement, the factors that keep them together, and the processes leading to the structures composed of many cells are only now beginning to be understood. Possibilities that may be key to their abilities are three models proposed elsewhere for different aspects of their biology. One hypothesis attempts to explain mound and fruiting body formation by assuming that the cells move in circular patterns around the major cell mass. The second explains gliding motility on the existence of shunts that periodically short out the proton gradient across the cell membrane, causing expansion and contraction of portions of the cell. The third model proposes that occasionally cells arise that move unidirectional instead of back and forth. These few cells may lead the majority of cells in new directions. BioEssays 20:1030–1038, 1998. © 1998 John Wiley & Sons, Inc.     

EXTINCTION DUE TO EVOLUTION OF A COMPETITOR

When Drosophila simulans and Drosophila funebris were cultured together in population cages over many generations, there was a prolonged period of apparently stable coexistence followed by a rapid exclusion of D. funebris. As both species maintained large population sizes in monocultures it follows that the extinctions of D. funebris in the mixed-species cultures must have been caused by D. simulans. The time to extinction of D. funebris ranged from 26 weeks in one cage, to between 40 and 48 weeks in the other five. To test the idea that an evolutionary increase in competitive ability of D. simulans had occurred during the course of its interaction with D. funebris, a single-generation experiment was set up. In this experiment the interspecific competitive ability of a population of D. simulans that had been in competition with D. funebris for 44 weeks was compared to that of a stock population that had had no previous contact with D. funebris. In this experiment both stock and precompeted populations of D. simulans increased the egg-to-adult development time of D. funebris. However, precompeted D. simulans caused a significantly greater increase in the development time of D. funebris than did stock D. simulans. Thus D. simulans had evolved an increase in competitive ability as a result of its interaction with D. funebris. Development time is important because in the population cages the resource bottles—in which the larvae reside—were replaced every three weeks. An increase in development time of D. funebris in the multigeneration experiment similar to that observed in the single-generation experiment would lead to a rapid decrease in adult population size, resulting in the extinction of this species, as was observed to happen.     

The Reproductive Behavior of Acanthurus nigrofuscus (Forskal) and other Surgeonfishes (Fam. Acanthuridae) off Eilat,Israel (Gulf of Aqaba,Red Sea)

The reproductive behavior of Acanthurus nigrofuscus, a common surgeonfish of the Red Sea, is described for two overlapping populations inhabiting the coral reefs off Eilat, Israel (Gulf of Aqaba). The spectacular daily spawning activities, often involving aggregations of thousands of individuals, as well as the often long distance migrations to and from the spawning grounds by groups in highly organized formations are characterized in detail. Evidence is provided that the precise timing of these various phenomena is controlled by ambient light levels during the late afternoon. Less detailed information is also provided on comparable activities of two other surgeonfishes from the same reefs: Ctenochaetus striatus and Zebrasoma xanthurum. Finally, comparisons are made of reproduction and its associated environmental controls among populations of the same and related species of surgeonfishes at widely distributed locations in the Indo-Pacific.