Further studies on the compatibility between s. intercalatum from cameroun and za?re and species of bulinus.

The results from the infection experiments with Schistosoma intercalatum from Cameroun and from Za?re and the intermediate hosts, belonging to B. forskalii and B. globosus, could be divided into groups according to the degree of compatibility with the schistosomes. This was indicated by the total cercariae production per 100 exposed snails (TCP/100 exp. snails). B. forskalii from Kinshasa, Za?re were the snails which were most compatible with S. intercalatum from Cameroun, and B. globosus populations tested were refractory. The TCP/100 exposed snails was about 300,000 for the populations of B. forskalii from Kinshasa compared with the low production for B. forskalii from Cameroun of 125,000. B. wrighti from South Arabia produced 155,000 cercariae per 100 exposed snails. B. cernicus from Mauritius could be separated into two types according to the compatibility with S. intercalatum from Cameroun, the TCP/100 exposed snails was 31,000 and 267,000, respectively. B. globosus from Kinshasa, Za?re, was very compatible with S. intercalatum from Za?re and the TCP/100 exposed snails was very high, and 300,000. An albino strain of B. globosus from Rhodesia was the most compatible snail having a TCP/100 exposed snails of 2.4 million cercariae. Other strains of B. globosus from Cameroun and Togo were refractory and less susceptible. It was also possible to infect B. africanus and the two tested populations from Kenya and Tanzania, producing 15,000 and 179,000 cercariae per 100 exposed snails, respectively.     

A study on snail location by Fasciola hepatica using radioisotopically labelled miracidia.

A number of common freshwater molluscs were exposed to Fasciola hepatica miracidia labelled in vivo with radioselenium. Radioactivity was rapidly incorporated in all lymnaeid species tested (L. stagnalis, L. tomentosa and L. truncatula) whereas no radioactivity could be demonstrated in non-lymnaeid pulmonate species (Aplexa hypnorum, Physa acuta, Physa fontinalis, Anisus vortex, Gyraulus albus and Planorbis planorbis) or in the prosobranchs Valvata cristata and Valvata piscinalis. However, the prosobranchs Bithynia leachii, Bithynia tentaculata and Potamopyrgus jenkinsi showed a slow but significant uptake of radioactivity which was presumably explained by uptake of labelled miracidia through a 'filter-feeding' mechanism. Sphaerium corneum, a true filter-feeder, showed a similar course of uptake of radioactivity.     

Further studies on the properties of glucose 6-phosphate dehydrogenase from the coccidium Eimeria stiedai (Protozoa).

1. Glucose 6-phosphate dehydrogenase from Eimeria stiedai does not reduce NAD or any of its analogs tested. It does reduce NADP and its thionicotinamide and 3-acetylpyridine analogs. 2. It will accept D-glucose as substrate, but not 2-deoxy-D-glucose, glucose 1-phosphate, or 2-deoxy-D-glucose 6-phosphate. 3. Its response to a number of compounds that activate or inhibit the enzyme from other organisms has been determined. 4. The molecular weight is ca. 240,000 by gel chromatography, and only one isoenzyme could be detected by disc electrophoresis. 5. The enzyme resists conditions that commonly cause dissociation to lighter weight active forms.     

Calcium electroporation in three cell lines: a comparison of bleomycin and calcium,calcium compounds,and pulsing conditions

Background

Electroporation with calcium (calcium electroporation) can induce ATP depletion-associated cellular death. In the clinical setting, the cytotoxic drug bleomycin is currently used with electroporation (electrochemotherapy) for palliative treatment of tumors. Calcium electroporation offers several advantages over standard treatment options: calcium is inexpensive and may readily be applied without special precautions, as is the case with cytostatic drugs. Therefore, details on the use of calcium electroporation are essential for carrying out clinical trials comparing calcium electroporation and electrochemotherapy.

Methods

The effects of calcium electroporation and bleomycin electroporation (alone or in combination) were compared in three different cell lines (DC-3F, transformed Chinese hamster lung fibroblast; K-562, human leukemia; and murine Lewis Lung Carcinoma). Furthermore, the effects of electrical pulsing parameters and calcium compound on treatment efficacy were determined.

Results

Electroporation with either calcium or bleomycin significantly reduced cell survival (p < 0.0001), without evidence of a synergistic effect. Cellular death following calcium or bleomycin treatment occurred at similar applied voltages, suggesting that similar parameters should be applied. At equimolar concentrations, calcium chloride and calcium glubionate resulted in comparable decreases in cell viability.

Conclusions

Calcium electroporation and bleomycin electroporation significantly reduce cell survival at similar applied voltage parameters. The effect of calcium electroporation is independent of calcium compound.

General significance

This study strongly supports the use of calcium electroporation as a potential cancer therapy and the results may aid in future clinical trials.     

Time Clustered Sampling Can Inflate the Inferred Substitution Rate in Foot-And-Mouth Disease Virus Analyses

With the emergence of analytical software for the inference of viral evolution, a number of studies have focused on estimating important parameters such as the substitution rate and the time to the most recent common ancestor (t _MRCA) for rapidly evolving viruses. Coupled with an increasing abundance of sequence data sampled under widely different schemes, an effort to keep results consistent and comparable is needed. This study emphasizes commonly disregarded problems in the inference of evolutionary rates in viral sequence data when sampling is unevenly distributed on a temporal scale through a study of the foot-and-mouth (FMD) disease virus serotypes SAT 1 and SAT 2. Our study shows that clustered temporal sampling in phylogenetic analyses of FMD viruses will strongly bias the inferences of substitution rates and t _MRCA because the inferred rates in such data sets reflect a rate closer to the mutation rate rather than the substitution rate. Estimating evolutionary parameters from viral sequences should be performed with due consideration of the differences in short-term and longer-term evolutionary processes occurring within sets of temporally sampled viruses, and studies should carefully consider how samples are combined.