Interaction network of the ribosome assembly machinery from a eukaryotic thermophile.

Ribosome biogenesis in eukaryotic cells is a highly dynamic and complex process innately linked to cell proliferation. The assembly of ribosomes is driven by a myriad of biogenesis factors that shape pre-ribosomal particles by processing and folding the ribosomal RNA and incorporating ribosomal proteins. Biochemical approaches allowed the isolation and characterization of pre-ribosomal particles from Saccharomyces cerevisiae, which lead to a spatiotemporal map of biogenesis intermediates along the path from the nucleolus to the cytoplasm. Here, we cloned almost the entire set (∼180) of ribosome biogenesis factors from the thermophilic fungus Chaetomium thermophilum in order to perform an in-depth analysis of their protein-protein interaction network as well as exploring the suitability of these thermostable proteins for structural studies. First, we performed a systematic screen, testing about 80 factors for crystallization and structure determination. Next, we performed a yeast 2-hybrid analysis and tested about 32,000 binary combinations, which identified more than 1000 protein-protein contacts between the thermophilic ribosome assembly factors. To exemplary verify several of these interactions, we performed biochemical reconstitution with the focus on the interaction network between 90S pre-ribosome factors forming the ctUTP-A and ctUTP-B modules, and the Brix-domain containing assembly factors of the pre-60S subunit. Our work provides a rich resource for biochemical reconstitution and structural analyses of the conserved ribosome assembly machinery from a eukaryotic thermophile.

Aqueous extract of Ocimum tenuiflorum decreases levels of blood glucose in induced hyperglycemic tilapia (Oreochromis niloticus).

OBJECTIVE: To evaluate, in hyperglycemic tilapia [Oreochromis niloticus (O. niloticus)], the effect of this aqueous extract on blood glucose levels. METHODS: The hyperglycemia in O. niloticus was induced by adding glucose to fish pond water. An aqueous extract of Ocimum tenuiflorum (O. tenuiflorum) was prepared by boiling fresh leaves and the doses of 0, 40, 80, 200 and 400 mg per liter of pond water were tested. RESULTS: The blood sugar concentration for tilapia with hyperglycemic induced was an average of 50% higher than the control group. The blood glucose levels in tilapia after the induction of hyperglycemia were higher than the control group for 90 min after the treatment. The treatment with the aqueous extract of O. tenuiflorum dropped the serum glucose level of hyperglycemic tilapia until it was similar to that of the control group and was dose dependent. CONCLUSIONS: The results indicated that O. tenuiflorum was endowed with anti-hyperglycemic activity. To our knowledge, this is the first report on the use of fish as a diabetes model to test natural extracts from plants.

Use of the polymerase chain reaction (PCR) for early evaluation of etiological treatment in young adults, chronically infected with Trypanosoma cruzi

Foi realizado o tratamento etiológico com benznidazol, no Estado de Salta, Argentina, em 14 pacientes infectados crônicos por Trypanosoma cruzi, de 18 a 30 anos de idade, com Reação em Cadeia da Polimerase (PCR) positiva. Um grupo controle de cinco pacientes, da mesma idade, também com PCR positiva, não recebeu tratamento. O seguimento após tratamento foi realizado com PCR e sorologia convencional. Após 6 meses de tratamento foi observada negativização da PCR de 14/16 (85,7por cento) nos pacientes tratados versus 20por cento no grupo controle (p=0,001). A sorologia foi positiva em todos os pacientes depois do tratamento. Os resultados da PCR pós-tratamento, podem ser um indício de cura no tratamento de infectados chagásicos crônicos, adultos jovens.