Structure elucidation of new compounds from acidic treatment of the progestins gestodene and drospirenone

Gestodene acidic treatment afforded a single rearrangement product, namely 13-beta-ethyl-18,19-dinorpregna-4,14,16-trien-3,20-dione 3, which was originated through HCl-catalyzed Rupe rearrangement. Drospirenone acidic treatment yielded two epimeric lactones by addition of HCl to the 6beta,7beta-cyclopropane ring, namely 7beta-(chloromethyl)-15beta,16beta-methylene-3-oxo-17beta-pregn-4-ene-21,17-carbolactone 4 and 7beta-(chloromethyl)-15beta,16beta-methylene-3-oxo-17alpha-pregn-4-ene-21,17-carbolactone 5. The structure of the compounds was assessed by spectroscopic and crystallographic methods.     

Clinical versus ultrasound examination in the evaluation of hepatosplenic schistosomiasis mansoni in endemic areas

The best way to appraise the size of abdominal organs remains undefined. Herein we compare the size of liver and spleen in hepatosplenic schistosomiasis using clinical and ultrasound (US) examination, and the size of the organs measured by US with their visualization below the costal margin ("palpable by US"). For this study, 411 individuals from an endemic area for schistosomiasis mansoni in Brazil have been selected. We found that palpable spleens and left liver lobes are larger than non palpable ones. Also, 23% of normal spleens measured by US were palpable on clinical examination, and 22% of spleens increased in size on US were non palpable. A total of 21% of normal spleens were "palpable by US". We also found 54% of normal sized right liver lobes palpable on clinical examination, whilst 54% of the increased livers, measured by US, were non palpable. About 76% of normal right liver lobes were "palpable by US". We conclude that the association of clinical, ultrasound and magnetic resonance imaging (MRI) examinations, in the near future, should give the investigators the necessary tools to perform a more accurate clinical diagnosis of hepatosplenic schistosomiasis mansoni.     

Giardia duodenalis: analysis of secreted proteases upon trophozoite-epithelial cell interaction in vitro

Protease secretion by Giardia duodenalis trophozoites upon interaction with epithelial cells and its association with the parasite adhesion was studied in co-cultures of parasites with IEC6 epithelial cell monolayers in the presence or absence of protease inhibitors. Proteolytic activity in supernatants from trophozoites was enhanced when they were co-cultured with IEC6 cells. This activity was strongly inhibited by pre-incubation of live trophozoites with E-64 and TPCK and a concomitant inhibition of parasite adhesion to IEC6 cells was observed. These data suggest that trophozoites secrete cysteine-type proteases that play a role in the adhesion of G. duodenalis to epithelial cells.     

Hepatic stereology of Schistosomiasis mansoni infected-mice fed a high-fat diet

High-fat diets induce weight gain and fatty liver in wild-type mice. Schistosomiasis mansoni infection also promotes hepatic injury. This study was designed to quantify hepatic alterations in schistosomiasis mansoni-infected mice fed a high fat-rich chow compared to mice fed a standard rodent chow, using stereology. Female SW mice fed each either high-fat diet (29% lipids) or standard chow (12% lipids) over 8 months, and then were infected with Schistosoma mansoni cercariae. Four experimental groups were studied: infected mice fed a high-fat diet (IHFC) or standard chow (ISC), uninfected mice fed a high-fat diet (HFC) or standard chow (SC). Mice were sacrificed during early infection (9 weeks from exposure). The following hepatic biometry and the stereology parameters were determined: volume density (hepatocytes [h], sinusoids [s], steatosis [st] and hepatic fibrosis [hf]); numerical density (hepatocyte nuclei - Nv[h]); absolute number of total hepatocyte N[h], normal hepatocyte N[nh], and binucleated hepatocyte N[bh], percentage of normal hepatocyte P[nh] and binucleated hepatocyte P[bh]. IHFC and HFC groups exhibited TC, HDL-C, LDL-C, and body mass significantly greater (p < 0.05) than control group. No significant differences were found regards liver volume (p = 0.07). Significant differences were observed regards P[nh] (p = 0.0045), P[bh] (p = 0.0045), Nv[h] (p = 0.0006), N[h] (p = 0.0125), N[bh] (p = 0.0164) and N[nh] (p = 0.0078). IHFC mice group presented 29% of binucleated hepatocytes compared to HFC group (19%), ISC group (17%) and SC (6%). Volume density was significantly different between groups: Vv[h] (p = 0.0052), Vv[s] (p = 0.0025), Vv[st] (p = 0.0004), and Vv[hf] (p = 0.0007). In conclusion, schistosomiasis mansoni infection with concurrent high-fat diet promotes intensive quantitative changes in hepatic structure, contributing to an increasing on hepatic regeneration.     

VEGF gene variability and type 1 diabetes: evidence for a protective role

Vascular endothelial growth factor (VEGF) is a multifunctional cytokine originally described as an angiogenic factor. A number of reports have recently demonstrated that VEGF increases pancreatic islet survival after islet transplantation by stimulating angiogenesis and improving islet revascularization. Whether VEGF can protect from the autoimmune destruction of insulin-producing beta-cells that characterizes the development of type 1 diabetes is presently unknown. To clarify this issue, we studied the association of three polymorphisms of the promoter region of VEGF with type 1 diabetes in the Italian and the Finnish populations. The polymorphisms considered [C(-2578)A, G(-1190)A, and G(-1154)A] are known to modulate in vitro and in vivo VEGF expression. We found that VEGF promoter genotypes are associated with type 1 diabetes in both populations, but with different combinations. In Italian individuals, the -2578AA and -1190AA genotypes are associated with type 1 diabetes and accelerate its onset, while in Finnish individuals, -1154GG and -1190GG protect from type 1 diabetes and delay its onset. In conclusion, because the expected functional consequence of both genotype combinations is a reduced VEGF expression in diabetic patients, we propose a protective role of VEGF in the development of type 1 diabetes.     

Dynamics of Long-term Anhydrobiotic Survival of Lichen-dwelling Tardigrades

It is not rare to find in references that anhydrobiotic tardigrades can survive for more than a century. However, a closer look at the empirical evidence provides very little support that tardigrades are capable of surviving dried for such a long time. In order to resolve this discrepancy, we carried out a study to evaluate the long-term survival of naturally dried tardigrades. A large fragment of dry lichen (Xanthoria parietina) was collected in the field two days after a rainy day in 1999. The dry lichen was stored inside a paper bag in the laboratory at room temperature and humidity and under atmospheric oxygen exposure. Replicates of the dry lichen were re-hydrated after various time periods of storage, with all tardigrades extracted and the survivors enumerated. Five species of tardigrades were found, but two of them only occasionally. Ramazzottius oberhaeuseri, Echiniscus testudo and Echiniscus trisetosus were sufficiently represented for statistical analysis. At the beginning of the experiment 91.1% of R. oberhaeuseri and 71.7% of Echiniscus spp. were alive. R. oberhaeuseri survived up to 1604 days, while Echiniscus spp. lived up to 1085 days. Recovery after four years of anhydrobiosis has to be considered a very good long-term survival, which is important from an ecological and evolutionary point of view.     

Synthesis, characterization, X-ray molecular structure and catalase-like activity of a non-heme iron complex: Dichloro[N-propanoate-N,N-bis-(2-pyridylmethyl)amine]iron(III)

In this work we present the synthesis and characterization of the complex dichloro[N-propanoate-N,N-bis-(2-pyridylmethyl)amine]iron(III) [Fe^III(PBMPA)Cl₂]. The ligand LiPBMPA was synthesized through the Michael reaction of BMPA with methylacrylate, followed by alkaline hydrolysis. The complex [Fe^III(PBMPA)Cl₂] has been synthesized by the reaction of the ligand with FeCl₃ · H₂O and was mainly characterized by cyclic voltammetry, conductivimetry, and electronic, infrared and Mössbauer spectroscopies, and by X-ray structural analysis, which showed an iron center coordinated by one carboxylate oxygen in a monodentate way, one tertiary amine, two pyridine groups and two chloride ions. It has been proposed that in water the chloride ligands are shifted by the solvent molecules and the species [Fe^III(PBMPA)(H₂O)₂]Cl₂ is predominant. The catalase-like activity of the complex was tested in water, and it proved to be active in the hydrogen peroxide dismutation. Kinetics studies were conducted following the initial rates method. The reaction is first order in relation to both the complex and the hydrogen peroxide. Based on the presence of a lag phase that depends on the initial complex concentration, we propose that the active species that shows in situ catalase-like activity, is a binuclear complex.     

Phenological models for blooming of apple in a mountainous region

Six phenological series were available for ‘Golden Delicious’ apple blooming at six sites in Trentino, an alpine fruit-growing region. Several models were tested to predict flowering dates, all involving a “chilling and forcing” approach. In many cases, application of the models to different climatic conditions results in low accuracy of prediction of flowering date. The aim of this work is to develop a model with more general validity, starting from the six available series, and to test it against five other phenological series outside the original area of model development. A modified version of the “Utah” model was the approach that performed best. In fact, an algorithm using “chill units” for rest completion and a thermal sum for growing-degree-hours (GDH), whose efficiency changes over time depending on the fraction of forcing attained, yielded a very good prediction of flowering. Results were good even if hourly temperatures were reconstructed from daily minimum and maximum values. Errors resulting from prediction of flowering data were relatively small, and root mean square errors were in the range of 1–6 days, being <2 days for the longest phenological series. In the most general form of the model, the summation of GDH required for flowering is not a fixed value, but a function of topoclimatic variables for a particular site: slope, aspect and spring mean temperature. This approach allows extension of application of the model to sites with different climatic features outside the test area.     

A screen for genes of heme uptake identifies the FLC family required for import of FAD into the endoplasmic reticulum

Although Candida albicans and Saccharomyces cerevisiae express very similar systems of iron uptake, these species differ in their capacity to use heme as a nutritional iron source. Whereas C. albicans efficiently takes up heme, S. cerevisiae grows poorly on media containing heme as the sole source of iron. We identified a gene from C. albicans that would enhance heme uptake when expressed in S. cerevisiae. Overexpression of CaFLC1 (for flavin carrier 1) stimulated the growth of S. cerevisiae on media containing heme iron. In C. albicans, deletion of both alleles of CaFLC1 resulted in a decrease in heme uptake activity, whereas overexpression of CaFLC1 resulted in an increase in heme uptake. The S. cerevisiae genome contains three genes with homology to CaFLC1, and two of these, termed FLC1 and FLC2, also stimulated growth on heme when overexpressed in S. cerevisiae. The S. cerevisiae Flc proteins were detected in the endoplasmic reticulum and the FLC genes encoded an essential function, as strains deleted for either FLC1 or FLC2 were viable, but deletion of both FLC1 and FLC2 was synthetically lethal. FLC gene deletion resulted in pleiotropic phenotypes related to defects in cell wall integrity. High copy suppressors of this synthetic lethality included three mannosyltransferases, VAN1, KTR4, and HOC1. FLC deletion strains exhibited loss of cell wall mannose phosphates, defects in cell wall assembly, and delayed maturation of carboxypeptidase Y. Permeabilized cells lacking FLC proteins exhibited dramatic loss of FAD import activity. We propose that the FLC genes are required for import of FAD into the lumen of the endoplasmic reticulum, where it is required for disulfide bond formation.