TLR2 mediates immunity to experimental cysticercosis

Information concerning TLR-mediated antigen recognition and regulation of immune responses during helminth infections is scarce. TLR2 is a key molecule required for innate immunity and is involved in the recognition of a wide range of viruses, bacteria, fungi and parasites. Here, we evaluated the role of TLR2 in a Taenia crassiceps cysticercosis model. We compared the course of T. crassiceps infection in C57BL/6 TLR2 knockout mice (TLR2^-/-) with that in wild type C57BL/6 (TLR2^+/+) mice. In addition, we assessed serum antibody and cytokine profiles, splenic cellular responses and cytokine profiles and the recruitment of alternatively activated macrophages (AAMφs) to the site of the infection. Unlike wild type mice, TLR2^-/- mice failed to produce significant levels of inflammatory cytokines in either the serum or the spleen during the first two weeks of Taenia infection. TLR2^-/- mice developed a Th2-dominant immune response, whereas TLR2^+/+ mice developed a Th1-dominant immune response after Taenia infection. The insufficient production of inflammatory cytokines at early time points and the lack of Th1-dominant adaptive immunity in TLR2^-/- mice were associated with significantly elevated parasite burdens; in contrast, TLR2^+/+ mice were resistant to infection. Furthermore, increased recruitment of AAMφs expressing PD-L1, PD-L2, OX40L and mannose receptor was observed in TLR2^-/- mice. Collectively, these findings indicate that TLR2-dependent signaling pathways are involved in the recognition of T. crassiceps and in the subsequent activation of the innate immune system and production of inflammatory cytokines, which appear to be essential to limit infection during experimental cysticercosis.     

Guías clínicas de fractura de cadera. Comparación de sus principales recomendaciones

Hip fracture is the most severe complication of osteoporosis, and despite being a frequent health problem, there is a wide variability in both the health care provided to these patients and the results achieved after their treatment. Clinical guidelines are a tool that helps to reduce this variability. The authors of this review try to give a panoramic and comparative view of the key recommendations proposed by the main guidelines for the hospital care of hip fracture patients. Recommendations on the care in the acute phase are reviewed, particularly the initial hospital management, use of tools, preventive measures to avoid medical complications, surgery related aspects, treatment of usual clinical problems, and shared orthopaedic and geriatric care. Circulating and putting into practice the main recommendations will help to improve the health care provided to these patients and obtain better outcomes.     

Proteomic and morphometric study of the in vitro interaction between <Emphasis Type="Italic">Oncidium sphacelatum</Emphasis> Lindl. (Orchidaceae) and <Emphasis Type="Italic">Thanatephorus</Emphasis> sp. RG26 (Ceratobasidiaceae)

Orchidaceae establish symbiotic relationships with fungi in the Rhizoctonia group, resulting in interactions beneficial to both organisms or in cell destruction in one of them (pathogenicity). Previous studies have focused mostly on terrestrial species with a few, preliminary studies, on epiphytes. To further our understanding of the molecular mechanisms involved in these symbioses, we evaluated the interaction between Oncidium sphacelatum Lindl. and the mycorrhizal fungus Thanatephorus sp. strain RG26 (isolated from a different orchid species) in vitro using morphometric and proteomic analyses. Evidence from the morphometric and microscopic analysis showed that the fungus promoted linear growth and differentiation of orchid protocorms during 98 days interaction. On day 63, protocorm development was evident, so we analyzed the physiological response of both organisms at that moment. Proteome results suggest that orchid development stimulated by the fungus apparently involves cell cycle proteins, purine recycling, ribosome biogenesis, energy metabolism, and secretion that were up-regulated in the orchid; whereas in the fungus, a high expression of proteins implicated in stress response, protein-protein interaction, and saccharides and protein biosynthesis were found in the symbiotic interaction. This is the first work reporting proteins differentially expressed in the epiphytic orchid-fungus interaction and will contribute to the search for molecular markers that will facilitate the study of this symbiosis in both wild orchids and those in danger of extinction.     

Kinetic resolution of racemic 5,6-epoxy-bicyclo[2.2.1]heptane-2-one using genetically engineered Saccharomyces cerevisiae

(+)-5,6-Epoxy-bicyclo[2.2.1]heptane-2-one, (+)-1, and endo-(−)-5,6-epoxy-bicyclo[2.2.1]heptane-2-ol, endo-(−)-2, were obtained by kinetic resolution of rac-1 by asymmetric bioreduction catalyzed by whole cells of a genetically engineered Saccharomyces cerevisiae yeast strain. The strain, TMB4100, had 1% phosphoglucose isomerase (PGI) activity and overexpressed a specific short-chain dehydrogenase, encoded by the gene YMR226c. The whole cell biocatalyst was demonstrated to be significantly inactivated within 24 h, thus restricting the reaction to low concentration. Despite this, the resolution method could be used to produce optically pure (+)-1 and endo-(−)-2 from the racemic mixture at 5 g/L substrate. At optimal conditions, 1 g of rac-1 was kinetically resolved to give (+)-1 in 95% ee and 28% yield and endo-(−)-2 in 74% ee, 80% de and 45% yield.     

Composition of the sterol fraction in horse chestnut

The Δ⁷-and Δ⁵-sterol fractions were isolated from the unsaponifiable matter of ripe, air dried, chestnut seed. The Δ⁷-sterol fraction amounted to 18.4% and the Δ⁵-sterol fraction amounted to 8.2% of the unsaponifiable matter. In the Δ⁷-sterol fraction three components were identified as Δ⁷-campesterol, α-spinasterol and Δ⁷-stigmastenol. One component was probably Δ^5,7-stigmastadienol and five components remained unidentified. Δ⁷-stigmastenol and α- spinasterol were the major components and amounted to 74.8% of the fraction. In the Δ⁵-sterol fraction at least ten components were found. Five of them were identified as cholesterol, campesterol, stigmasterol, sitosterol and Δ⁴-stigmasten-3-one. Stigmasterol and sitosterol amounted to 73.6% of the fraction.     

Optimal use of restriction enzymes in the analysis of human DNA polymorphism

Summary Numerous biological factors have an effect upon the probability of the presence of a theoretical restriction site at a given point, ( ), in a DNA molecule, where n represents the number of base pairs composing the site. Indeed, it is a fact that the ratio does not usually equal unity. In addition, the sequence of the nucleotides appears to change haphazardly, with certain dinucleotides present more often than others. When considering , it is observed that the influence of this first parameter is very important for sites with either four or six base pairs. The balance of the average frequency of each site according to the preponderance of certain dinucleotides and the G+C content has been the subject of an involved study which makes use of a certain number of restriction enzymes which are commercially available. The important frequency variations of different sites are due primarily to the presence of one or two GC doublets which go as far as reducing the frequency by a factor of 3.     

Structural and functional roles of the N1- and N3-protons of psi at tRNA's position 39.

Pseudouridine at position 39 (Psi(39)) of tRNA's anticodon stem and loop domain (ASL) is highly conserved. To determine the physicochemical contributions of Psi(39)to the ASL and to relate these properties to tRNA function in translation, we synthesized the unmodified yeast tRNA(Phe)ASL and ASLs with various derivatives of U(39)and Psi(39). Psi(39)increased the thermal stability of the ASL (Delta T (m)= 1.3 +/- 0.5 degrees C), but did not significantly affect ribosomal binding ( K (d)= 229 +/- 29 nM) compared to that of the unmodified ASL (K (d)= 197 +/- 58 nM). The ASL-Psi(39)P-site fingerprint on the 30S ribosomal subunit was similar to that of the unmodified ASL. The stability, ribosome binding and fingerprint of the ASL with m(1)Psi(39)were comparable to that of the ASL with Psi(39). Thus, the contribution of Psi(39)to ASL stability is not related to N1-H hydrogen bonding, but probably is due to the nucleoside's ability to improve base stacking compared to U. In contrast, substitutions of m(3)Psi(39), the isosteric m(3)U(39)and m(1)m(3)Psi(39)destabilized the ASL by disrupting the A(31)-U(39)base pair in the stem, as confirmed by NMR. N3-methylations of both U and Psi dramatically decreased ribosomal binding ( K (d)= 1060 +/- 189 to 1283 +/- 258 nM). Thus, canonical base pairing of Psi(39)to A(31)through N3-H is important to structure, stability and ribosome binding, whereas the increased stability and the N1-proton afforded by modification of U(39)to Psi(39)may have biological roles other than tRNA's binding to the ribosomal P-site.     

Toxic effect of DDT and endosulfan in white shrimp postlarvae Litopenaeus vannamei (Decapoda: Penaeidae) from Chiapas, Mexico

We analized acute toxicity in white shrimp (Litopenaeus vannamei) postlarvae exposed to two chlorinated pesticides, DDT and endosulfan, under laboratory conditions during 168 hours, with controlled temperature (29 +/- 1 degrees C), salinity (3 +/- 1%o) and pH (8 +/- 1). Median lethal concentrations (LC50), "incipient" LC50, median lethal time (LT50) the "maximum acceptable concentration of the toxic compound" (MACT) and "the safety level" (SL) were determined. The concentration of the compounds at which organism growth was reduced by 5 and 50% (EC5 and EC50), as well as changes in oxygen consumption patterns were determined in the surviving postlarvae. They were very sensitive to both compounds and DDT was thrice as toxic as endosulfan. Growth rate decreased 50% and 80% with endosulfan and DDT, respectively, at the experimental pestice concentration. The low resistance of postlarvae to DDT and endosulfan suggests that additional inflow of these pesticides into the aquatic system could affect the rate of shrimp production in the area.     

Characterization of a wine-like beverage obtained from sugarcane juice

Two yeasts (Saccharomyces cerevisiae and Saccharomyces cerevisiae var ellipsoideus)were tested for their ability to ferment sugarcane (Saccharum officinarum) juice. In order to do this, time course studies of volatile, fixed, and total acidity, pH, alcohol, total sugars and °Bx were performed and the presence of methanol was tested. The fermentation studies were carried out at 25, 28 and 30 °C and the juice was inoculated with 1 and 5% (v/v) suspensions of both yeasts containing 1 × 10⁸ cells ml⁻¹. Time course studies indicated a similar fermentative pattern at the three temperatures evaluated, hence 25 °C was chosen as the cheapest alternative. The size of the inoculum made no difference in the fermentation. Analyses of the sugarcane juice wine showed the following results: pH, 3.2; alcohol, 10 °GL; total solids, 16.5 g l⁻¹; ash, 1.4 g l⁻¹; total acidity, 5.4 g l⁻¹; volatile acidity, 0.12 g l⁻¹; fixed acidity, 5.3 g l⁻¹ and no methanol was detected. Two additional products were obtained after adding passion fruit juice and roselle (Hibiscus sabdarifa Linn) concentrates. The fruit-flavoured wines were significantly preferred (P ≤ 0.05) over the plain product. These results indicated that the elaboration of wine-like beverages is a good alternative use for sugarcane.