The Upper Tremadocian (Ordovician) graptolite Bryograptus: taxonomy, biostratigraphy and biogeography

Abstract:  The taxonomy, biostratigraphical and palaeogeographical distribution of the Lower Ordovician graptolite genus Bryograptus is evaluated. Bryograptus is recognized as a distinct triradiate anisograptid with a multiramous, pendent rhabdosome. The species of the genus Bryograptus can be interpreted as shallow water faunal elements with a strongly limited biogeographical distribution to the Atlantic Faunal Realm. Bryograptus is restricted to a narrow interval in the Upper Tremadocian, the Bryograptus Biozone of Scandinavia and South America (Argentina), making it a taxon with a high potential for precise biostratigraphical correlations. The proximal end development can be used to differentiate the genus Bryograptus from other pendent multiramous graptoloid genera with a homoplastic rhabdosome development. Characteristics of the proximal end development and structure easily differentiate these genera in relief specimens, but not in flattened material.     

Stimulation of dieldrin elimination by a thiouracil derivative and DDT in the rat: Enhancement of dieldrin oxidative metabolism?

Oral treatment of rats with either DDT or 1-benzyl-2-thio-5,6-dihydrouracil (BTDU) enhanced the elimination of intraperitoneally administered [¹⁴C]dieldrin. Both DDT and BTDU caused a severalfold increase in the urinary elimination of [¹⁴C]dieldrin. The increase in [¹⁴C]dieldrin elimination in the feces was less pronounced.     

Technical and statistical improvements for flow cytometric DNA analysis of paraffin-embedded tissue

Flow cytometric DNA analysis of paraffin-embedded solid tumors has permitted review of large series of archival tissue in attempts to relate abnormal DNA content to prognosis. Limitations of the technique include: 1) a laborious, time-consuming procedure; 2) variation in technique between laboratories; and 3) lack of an objective method of computing DNA indices. Critical evaluation of our technique has shortened the time involved in dewaxing and rehydration, selectively utilized patient's own normal tissue as the internal standard, proved reproducibility of stored specimens, standardized DNA index computation, and developed a statistical analysis to confirm aneuploidy. These technical improvements and the development of a statistical analysis provide a way to shorten the procedure time and standardize the data generated from flow cytometric DNA analysis so as to improve the quality of retrospective reviews of paraffin-embedded tumors and accelerate the definition of flow cytometry's role as a prognostic indicator.     

Antischistosomal,antionchocercal and antitrypanosomal potentials of some Ghanaian traditional medicines and their constituents

BackgroundGhana is endemic for some neglected tropical diseases (NTDs) including schistosomiasis, onchocerciasis and lymphatic filariasis. The major intervention for these diseases is mass drug administration of a few repeatedly recycled drugs which is a cause for major concern due to reduced efficacy of the drugs and the emergence of drug resistance. Evidently, new treatments are needed urgently. Medicinal plants, on the other hand, have a reputable history as important sources of potent therapeutic agents in the treatment of various diseases among African populations, Ghana inclusively, and provide very useful starting points for the discovery of much-needed new or alternative drugs.Methodology/Principal findingsIn this study, extracts of fifteen traditional medicines used for treating various NTDs in local communities were screened in vitro for efficacy against schistosomiasis, onchocerciasis and African trypanosomiasis. Two extracts, NTD-B4-DCM and NTD-B7-DCM, prepared from traditional medicines used to treat schistosomiasis, displayed the highest activity (IC₅₀ = 30.5 μg/mL and 30.8 μg/mL, respectively) against Schistosoma mansoni adult worms. NTD-B2-DCM, also obtained from an antischistosomal remedy, was the most active against female and male adult Onchocera ochengi worms (IC₅₀ = 76.2 μg/mL and 76.7 μg/mL, respectively). Antitrypanosomal assay of the extracts against Trypanosoma brucei brucei gave the most promising results (IC₅₀ = 5.63 μg/mL to 18.71 μg/mL). Incidentally, NTD-B4-DCM and NTD-B2-DCM, also exhibited the greatest antitrypanosomal activities (IC₅₀ = 5.63 μg/mL and 7.12 μg/mL, respectively). Following the favourable outcome of the antitrypanosomal screening, this assay was selected for bioactivity-guided fractionation. NTD-B4-DCM, the most active extract, was fractionated and subsequent isolation of bioactive constituents led to an eupatoriochromene-rich oil (42.6%) which was 1.3-fold (IC₅₀ <0.0977 μg/mL) more active than the standard antitrypanosomal drug, diminazene aceturate (IC₅₀ = 0.13 μg/mL).Conclusion/SignificanceThese findings justify the use of traditional medicines and demonstrate their prospects towards NTDs drug discovery.     

Protein folds, functions and evolution.

The evolution of proteins and their functions is reviewed from a structural perspective in the light of the current database. Protein domain families segregate unequally between the three major classes, the 32 different architectures and almost 700 folds observed to date. We find that the number of new topologies is still increasing, although 25 new structures are now determined for each new topology. The corresponding analysis and classification of function is only just beginning, fuelled by the genome data. The structural data revealed unexpected conservations and divergence of function both within and between families. The next five years will see the compilation of a definitive dictionary of protein families and their related functions, based on structural data which reveals relationships hidden at the sequence level. Such information will provide the foundation to build a better understanding of the molecular basis of biological complexity and hopefully to facilitate rational molecular design.