Synthesis and pharmacological evaluation of prenylated and benzylated pterocarpans against snake venom

Edunol (3), a pterocarpan isolated from Harpalyce brasiliana, a plant used in the northeast of Brazil against snakebites, was obtained by synthesis and showed antimyotoxic, antiproteolytic and PLA2 inhibitor properties. These proprieties could be improved through the synthesis of a bioisoster (5), where the prenyl group was replaced by the benzyl group.     

Simultaneous production of triploid and haploid eggs by triploid Squalius alburnoides (Teleostei: Cyprinidae)

The hybrid minnow Squalius alburnoides comprises diploid and polyploid forms with altered modes of reproduction. In the present paper, we report a cross where a triploid female generated both large, triploid and small, haploid eggs simultaneously, which were fertilized with S. pyrenaicus sperm. Although the large eggs were rarer (15%), they originated offspring with higher survivorship, so that tetraploids were dominant among the surviving siblings. The cross yielded apparently all female progeny. Inheritance patterns were inferred using four microsatellite markers and NORs (Nucleolus Organizer Regions) phenotypes, and suggested that haploid eggs were probably produced by an atypical hybridogenesis, in which the elimination of the unmatched genome permitted random segregation and recombination between the homospecific genomes, while the triploid eggs were clonal. The present results suggest that the occurrence of triploid unreduced eggs may be a new route for the natural tetraploidization in the complex.     

Enantioselective pharmacokinetics of lercanidipine in healthy volunteers

OBJECTIVE: The enantioselective kinetic disposition of lercanidipine, a dihydropyridine type of third-generation calcium antagonist, was investigated in six healthy male volunteers following a single 20 mg racemic oral dose. METHODS: Serial plasma samples were obtained from 0 to 24 h after drug administration. Lercanidipine enantiomers were analysed using a chiral LC-MS-MS method. RESULTS: The following differences (p < 0.05, Wilcoxon test) between (S) and (R) enantiomers were found (median): C(max) 2.071 ng mL(-1) versus 1.681 ng mL(-1); AUC(0-24)12.352 ng h mL(-1) versus 10.063 ng h mL(-1) and Cl/f 732.16 L h(-1) versus 1891.84 L h(-1). The AUC(0-infinity) values for (S)-LER were 1.21-fold higher than those for (R)-LER. CONCLUSION: The pharmacokinetics of LER was enantioselective in healthy volunteers following a single dose of 20 mg of the unlabeled racemic drug.     

Colitis induced by proteinase-activated receptor-2 agonists is mediated by a neurogenic mechanism

Proteinase-activated receptor-2 (PAR2) activation induces colonic inflammation by an unknown mechanism. We hypothesized that PAR2 agonists administered intracolonically in mice induce inflammation via a neurogenic mechanism. Pretreatment of mice with neurokinin-1 and calcitonin-gene-related peptide (CGRP) receptor antagonists or with capsaicin showed attenuated PAR2-agonist-induced colitis. Immunohistochemistry demonstrated a differential expression of a marker for the type-1 CGRP receptor during the time course of PAR2-agonist-induced colitis, further suggesting a role for CGRP. We conclude that PAR2-agonist-induced intestinal inflammation involves the release of neuropeptides, which by acting on their receptors cause inflammation. These results implicate PAR2 as an important mediator of intestinal neurogenic inflammation.     

Identification of PDZ5, a candidate universal minicircle sequence binding protein of Trypanosoma cruzi

The dodecamer universal minicircle sequence is a conserved sequence present in minicircles of trypanosomatid kinetoplast DNA studied so far. This sequence is recognised by a protein named universal minicircle sequence binding protein, described for Crithidia fasciculata, involved in minicircle DNA replication. We have identified a Trypanosoma cruzi gene homologue of the Crithidia fasciculata universal minicircle sequence binding protein. Similar to the Crithidia fasciculata universal minicircle sequence binding protein, the Trypanosoma cruzi protein, named PDZ5, contains five zinc finger motifs. Pulsed field gel electrophoresis indicated that the pdz5 gene is located in the chromosomal band XX of the Trypanosoma cruzi genome. The predicted amino acid sequence of PDZ5 shows a high degree of similarity with several trypanosomatid zinc finger proteins. Specific antibody raised against Crithidia fasciculata universal minicircle sequence binding protein recognises both the recombinant and endogenous PDZ5. The complete pdz5 coding sequence cloned in bacteria expresses a recombinant PDZ5 protein that binds specifically to the universal minicircle sequence dodecamer. These data strongly suggest that PDZ5 represents a Trypanosoma cruzi universal minicircle sequence binding protein.     

Crystal structure of a bacterial endospore coat component. A laccase with enhanced thermostability properties

Endospores produced by the Gram-positive soil bacterium Bacillus subtilis are shielded by a proteinaceous coat formed by over 30 structural components, which self-assemble into a lamellar inner coat and a thicker striated electrodense outer coat. The 65-kDa CotA protein is an abundant component of the outer coat layer. CotA is a highly thermostable laccase, assembly of which into the coat is required for spore resistance against hydrogen peroxide and UV light. Here, we report the structure of CotA at 1.7-A resolution, as determined by x-ray crystallography. This is the first structure of an endospore coat component, and also the first structure of a bacterial laccase. The overall fold of CotA comprises three cupredoxin-like domains and includes one mononuclear and one trinuclear copper center. This arrangement is similar to that of other multicopper oxidases and most similar to that of the copper tolerance protein CueO of Escherichia coli. However, the three cupredoxin domains in CotA are further linked by external interdomain loops, which increase the packing level of the structure. We propose that these interdomain loops contribute to the remarkable thermostability of the enzyme, but our results suggest that additional factors are likely to play a role. Comparisons with the structure of other monomeric multicopper oxidases containing four copper atoms suggest that CotA may accept the largest substrates of any known laccase. Moreover, and unlike other laccases, CotA appears to have a flexible lidlike region close to the substrate-binding site that may mediate substrate accessibility. The implications of these findings for the properties of CotA, its assembly and the properties of the bacterial spore coat structure are discussed.     

Production and characterization of a thermostable alpha-amylase from Nocardiopsis sp. endophyte of yam bean

Thermostable amylolytic enzymes have been currently investigated to improve industrial processes of starch degradation. Studies on production of alpha-amylase by Nocardiopsis sp., an endophytic actinomycete isolated from yam bean (Pachyrhizus erosus L. Urban), showed that higher enzyme levels were obtained at the end of the logarithmic growth phase after incubation for 72 h at pH 8.6. Maximum activity of alpha-amylase was obtained at pH 5.0 and 70 degrees C. The isolated enzyme exhibited thermostable properties as indicated by retention of 100% of residual activity at 70 degrees C, and 50% of residual activity at 90 degrees C for 10 min. Extracellular enzyme from Nocardiopsis sp. was purified by fractional precipitation with ammonium sulphate. After 60% saturation produced 1130 U mg-1 protein and yield was 28% with purification 2.7-fold. The enzyme produced by Nocardiopsis sp. has potential for industrial applications.     

Primate Population Densities and Sizes in Atlantic Forest Remnants of Northern Espírito Santo,Brazil

We surveyed primates in seven fragments of Atlantic forest ranging from 210 to 24,250 ha in Espírito Santo, southeastern Brazil. The objective was to assess their population densities and fragment-specific population sizes in order to discuss the survival of primates in this highly fragmented landscape. We used line-transect sampling for censusing primates and estimated densities via DISTANCE program. Alouatta fusca, Cebus apella, Callicebus personatus, and Callithrix geoffroyi live in the study area. Although variable, primate numbers were higher in larger than in smaller fragments, the likely reasons being the lack of space and food resources (fruits) and higher impact of mesopredators (small cats) in small fragments. The estimated densities are within the range reported for other Atlantic forest sites, except for brown howlers (Alouatta fusca), which were extremely rare. Estimates of population sizes were on the order of several hundreds to thousands of individuals/species in the large-sized fragments (ca. 20,000 ha), while comparable estimates for the other areas indicate <500 individuals/species in the medium-sized reserves (ca. 2,000 ha), and <50 individuals/species in the small fragments (ca. 200 ha). These estimates suggest that only Atlantic forest fragments 20,000 ha can harbor primate populations large enough to escape extinction in the long term. Given that <20% of all protected areas remaining in the Atlantic forest are 20,000 ha, management measures are urgently needed to improve primate conservation in this biome.