Eudesmane sesquiterpenes from Eupatorium Quadrangulare

The aerial part of Eupatorium quadrangulare afforded in addition to known compounds, a possible biosynthetic intermediate, quadrangulin A, of the eudesmanolides found in this species.     

Occurrence of neanderthal features in mandibles from the Atapuerca-SH site

Analysis of variation and distribution of evolutionary novelties is meaningful in understanding evolutionary processes. The mandible, as a morphological complex, comprises a large number of derived Neanderthal features. The present study investigates whether the features usually considered as European lineage apomorphies evolved independently; the occurrence of these features is studied in the mandibles from the Sima de los Huesos (SH) site (Atapuerca, Spain). For comparative purposes, a large sample of Neanderthal mandibles as well as older fossil Homo specimens have been used for the study. Chi-square tests were employed to test for independence. The SH mandibles present a set of features that clearly show the basic architecture of the Neanderthal mandible. A highly significant association is detected in the variation of the position of the mental foramen, the lateral prominence, and the anterior marginal tubercle, as well as in the development of retromolar space. However, a much weaker association is detected in the features of the internal aspect of the mandible, with a few exceptions. Features of the external aspect of the mandible occur chronologically earlier than those observed in the internal aspect. The hypothesis that two distinct and consecutive morphological processes have driven the emergence of the European lineage throughout the Middle Pleistocene is proposed. A first transformation affects the mandible by means of backwards displacement of the structures located at the external aspect, as well as the position of the condyle. A second process would modify the features of the internal aspect of the mandible, in which the relief of the masseteric and pterygoid fossae are affected, in association with a spatial rearrangement of the corpus and ramus. Analyzed individually, some of the considered features may be questioned as Neanderthal apomorphies (Trinkaus,1993; Franciscus and Trinkaus, 995); however, the joint occurrence of many of them suggests that the complex is an evolutionary novelty.     

COMPARATIVE GROWTH ANALYSIS OF TWO POPULATIONS OF PONTOPORIA BLAINVILLEI ON THE BRAZILIAN COAST

The von Bertalanffy growth model was applied to franciscana dolphins ( Pontoporia blainvillei ) incidentally caught in fishing nets on the São Paulo/Paraná coasts (25°00'–25°58'S), and compared with the growth of franciscanas incidentally caught on the Rio Grande do Sul coast (29°–33°S). In both locations, a difference was noted between the growth of males and females, confirming the sexual dimorphism of the body proportions of this dolphin. The growth curves of the dolphins from São Paulo/Paraná were significantly different ( P < 0.01) from those obtained from Rio Grande do Sul, with significantly smaller animals in the former area. On the São Paulo/Paraná coast, the stabilization of the growth curves happened at a total length of 113 and 129 cm for males ( n = 23) and females ( n = 18), respectively. In Rio Grande do Sul, they stabilized at 130 cm for the males ( n = 59) and at 146 cm ( n = 48) for the females. These results corroborate the morphometric differences previously mentioned in the literature, which resulted in the identification of a smaller northern form and a larger southern form of P. blainvillei . The data here presented can be used for future comparisons of changes in growth parameters of these two franciscana stocks and help to develop proper conservation programs for the species.     

Frequency of indicator bacteria,Salmonella and diarrhoeagenic Escherichia coli pathotypes on ready‐to‐eat cooked vegetable salads from Mexican restaurants

The presence of coliform bacteria, faecal coliforms, Escherichia coli, diarrhoeagenic E. coli pathotypes (DEP) and Salmonella were determined in ready‐to‐eat cooked vegetable salads (RECS) from restaurants in Pachuca city, Mexico. The RECS were purchased from three types of restaurants: national chain restaurants (A), local restaurants (B) and small restaurants (C). Two restaurants for each A and B, and three for C, were included. Forty RECS samples were purchased at each A and B restaurant and 20 at each C restaurant. Of the overall total of 220 analysed samples, 100, 98·2, 72·3, 4·1 and 4·1% had coliform bacteria, faecal coliforms, E. coli, DEP and Salmonella, respectively. Identified DEP included enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC) and Shiga toxin‐producing E. coli (STEC). The EPEC, ETEC and STEC were isolated each from 1·4% of samples. No E. coli O157:H7 were detected in any STEC‐positive samples. The analysis of Kruskal–Wallis anova and median test of microbiological data showed that the microbiological quality of RECS did not differ between the different restaurants (P > 0·05).

Significance and Impact of the Study

This is the first report regarding microbiological quality and Salmonella, enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC) and Shiga toxin‐producing E. coli (STEC) isolation from ready‐to‐eat cooked vegetable salads from Mexican restaurants. Ready‐to‐eat cooked vegetable salads could be an important factor contributing to the endemicity of EPEC, ETEC and STEC, and Salmonella caused gastroenteritis in Mexico.     

Transient Transcriptional Regulation of the CYS-C1 Gene and Cyanide Accumulation upon Pathogen Infection in the Plant Immune Response

Cyanide is produced concomitantly with ethylene biosynthesis. Arabidopsis (Arabidopsis thaliana) detoxifies cyanide primarily through the enzyme β-cyanoalanine synthase, mainly by the mitochondrial CYS-C1. CYS-C1 loss of function is not toxic for the plant and leads to an increased level of cyanide in cys-c1 mutants as well as a root hairless phenotype. The classification of genes differentially expressed in cys-c1 and wild-type plants reveals that the high endogenous cyanide content of the cys-c1 mutant is correlated with the biotic stress response. Cyanide accumulation and CYS-C1 gene expression are negatively correlated during compatible and incompatible plant-bacteria interactions. In addition, cys-c1 plants present an increased susceptibility to the necrotrophic fungus Botrytis cinerea and an increased tolerance to the biotrophic Pseudomonas syringae pv tomato DC3000 bacterium and Beet curly top virus. The cys-c1 mutation produces a reduction in respiration rate in leaves, an accumulation of reactive oxygen species, and an induction of the alternative oxidase AOX1a and pathogenesis-related PR1 expression. We hypothesize that cyanide, which is transiently accumulated during avirulent bacterial infection and constitutively accumulated in the cys-c1 mutant, uncouples the respiratory electron chain dependent on the cytochrome c oxidase, and this uncoupling induces the alternative oxidase activity and the accumulation of reactive oxygen species, which act by stimulating the salicylic acid-dependent signaling pathway of the plant immune system.The gaseous hormone ethylene is known to regulate multiple physiological and developmental processes in plants, such as seedling emergence, leaf and flower senescence, climacteric fruit ripening, and organ abscission. Ethylene is also involved in the response of plants to abiotic and biotic stresses (Wang et al., 2002; Broekaert et al., 2006; van Loon et al., 2006). Enhanced ethylene production is an early, active response of plants to the perception of pathogen attack and is associated with the induction of defense reactions. During ethylene biosynthesis, S-adenosyl-l-Met is converted to 1-aminocyclopropane-1-carboxylic acid (ACC) by ACC synthase. ACC is finally oxidized by ACC oxidase to form ethylene, carbon dioxide, and cyanide (Hartley et al., 1998; Wang et al., 2002). Hydrogen cyanide is a colorless and highly volatile liquid. The anion cyanide is toxic and renders the cells of an organism unable to use oxygen, primarily through the chelation of divalent and trivalent metal ions in the prosthetic groups of several metalloenzymes, including copper/zinc superoxide dismutase, catalase, nitrate and nitrite reductase, nitrogenase, peroxidases, and the mitochondrial cytochrome c oxidase (Isom and Way, 1984; Donato et al., 2007).Cyanide must be rapidly detoxified and metabolized by the plant to keep the concentration below toxic levels. Plants detoxify cyanide primarily through the enzyme β-cyanoalanine synthase (CAS), for which considerable levels of activity are constitutively found in many plant species. Rhodanese and mercaptopyruvate sulfurtransferase activities also make minor contributions to the cyanide detoxification process (Miller and Conn, 1980). CAS is a pyridoxal phosphate-dependent enzyme that converts Cys and cyanide to hydrogen sulfide and β-cyanoalanine, which is later converted to Asn, Asp, and ammonia by NIT4 class nitrilases (Piotrowski, 2008). Arabidopsis (Arabidopsis thaliana) plants carry the mitochondrial CAS CYS-C1 (At3g61440; Watanabe et al., 2008), which belongs to the family of β-substituted Ala synthase enzymes. The family also includes the three major O-acetyl-serine(thiol)lyase enzymes OAS-A1 (At4g14880), OAS-B (At2g43750), and OAS-C (At3g59760; Watanabe et al., 2008), the l-Cys desulfhydrase DES1 (At5g28030; Álvarez et al., 2010), the S-sulfocysteine synthase CS26 (At3g03630; Bermúdez et al., 2010), and the functionally unknown cytosolic isoforms CYS-D1 (At3g04940) and CYS-D2 (At5g28020). Mutations in CYS-C1 result in plants that accumulate cyanide and that display abnormal root hair (García et al., 2010), suggesting that cyanide has a signaling role in root development. The lack of the mitochondrial O-acetyl-serine(thiol)lyase isoform OAS-C, which is necessary to detoxify the sulfide released by the CAS activity, causes an accumulation of sulfide and cyanide and a root phenotype similar to the cys-c1 loss-of-function mutant (Álvarez et al., 2012b).Several authors have suggested that cyanide could act as a regulator of other metabolic processes in addition to performing the described role in plant root development (Siegien and Bogatek, 2006). It has been observed that this molecule is released during seed germination and that exogenously applied hydrogen cyanide breaks seed dormancy in several plants (Cohn and Hughes, 1986; Fol et al., 1989; Bogatek et al., 1991; Bethke et al., 2006). The role of cyanide as a regulatory molecule is not restricted to plants, and it has been demonstrated that cyanide is generated in leukocytes from Gly via a peroxidase (Stelmaszyńska, 1986) as well as in the central nervous system, where it has been hypothesized to act as a neuromodulator (Gunasekar et al., 2000; Cipollone and Visca, 2007). Cyanide production can be stimulated by opiates and decreased by treatment with muscarinic receptor agonists (Borowitz et al., 1997; Gunasekar et al., 2004).Despite the variety of known functions for cyanide in different organisms, the role of cyanide production in plants seems to have been unevaluated to date. In cyanogenic plants, cyanide is produced during the degradation of cyanogenic lipids and from the catabolism of cyanogenic glycosides (Poulton, 1990). Cyanide and cyanogenic compounds play an important role in plant defense against herbivores (Zagrobelny et al., 2008). In noncyanogenic plants, cyanide is a coproduct of ethylene biosynthesis. The molecule is also produced during the biosynthesis of camalexin, a phytoalexin formed in Arabidopsis plants upon infection by a large variety of microorganisms, including bacteria, fungi, and oomycetes (Glawischnig, 2007). During camalexin biosynthesis, the Trp-derived intermediate indole-3-acetonitrile is conjugated with Cys and serves as a substrate for the cytochrome P450 enzyme CYP71B15. This enzyme catalyzes the formation of the thiazoline ring as well as the release of cyanide and subsequent oxidative decarboxylation of dihydrocamalexic acid to camalexin (Glawischnig, 2007; Böttcher et al., 2009). Since both cyanide sources, camalexin and ethylene, are produced after pathogen attack, cyanide should be produced at significant levels during the plant response to pathogens. It has been shown that exogenous cyanide can enhance the resistance of tobacco (Nicotiana tabacum) and Arabidopsis leaves to Tobacco mosaic virus and Turnip vein clearing virus, respectively (Chivasa and Carr, 1998; Wong et al., 2002). Recently, it has been demonstrated that exogenously applied cyanide increases the resistance of young rice (Oryza sativa) plants to blast fungus infection, suggesting that cyanide rather than ethylene contributes to plant resistance (Seo et al., 2011).This work aims to further investigate the role of endogenously produced cyanide in the plant immune response by analyzing the behavior of Arabidopsis knockout mutants of the mitochondrial CAS CYS-C1 and the regulation of CYS-C1 in response to pathogen attack.     

Evolutionary trends in the columnar cactus genus Eulychnia (Cactaceae) based on molecular phylogenetics,morphology, distribution,and habitat

Populations of the columnar cactus genus Eulychnia (Cactaceae) are an iconic sight in the Chilean Atacama Desert. The most recent taxonomic treatment of the genus suggested to accept up to seven taxa at species level based on morphological data. To date, species boundaries and infrageneric relationships in Eulychnia have not been investigated using a molecular approach. In this study, sequence data were generated for six chloroplast markers (rpl32-trnL, trnH-psbA, trnL-trnF, trnQ-rps16, trnS-trnG, and ycf1) for the seven species. Where possible, samples were collected from the south and north of the distribution range of widely distributed species, as well as plants from two morphologically distinct populations in the Atacama and Coquimbo Regions. Evolutionary trends of morphological characters were investigated using ancestral state reconstruction, and the habitat of the Chilean taxa was taken into account based on latitudinal and altitudinal distribution, precipitation regime, and vegetation zones. Two major clades were retrieved in the molecular phylogenetic hypotheses, a northern clade and a southern clade, which can easily be distinguished morphologically by differences in rib shape and type of the indumentum of the pericarpel and the hypanthium. The only Eulychnia taxon found outside Chile is most commonly accepted as Eulychnia iquiquensis subsp. ritteri. However, its isolated geographic distribution and the fact that this taxon is not most closely related to E. iquiquensis but was retrieved as sister to the rest of the northern clade in our molecular phylogenetic results support the recognition of E. ritteri at species level. Our results also provide some support for the two recently published species, E. chorosensis (previously placed in E. acida s.l.) and E. taltalensis (previously considered to be part of E. breviflora s.l.). The relationships in the southern clade need further study.     

On the influence of point defects on the structural and electronic properties of graphene-like sheets: a molecular simulation study

The influence of vacancies and substitutional defects on the structural and electronic properties of graphene, graphene oxide, hexagonal boron nitride, and boron nitride oxide two-dimensional molecular models was studied using density functional theory (DFT) at the level of local density approximation (LDA). Bond length, dipole moment, HOMO–LUMO energy gap, and binding energy were calculated for each system with and without point defects. The results obtained indicate that the formation of a point defect does not necessary lead to structural instability; nevertheless, surface distortions and reconstruction processes were observed, mainly when a vacancy-type defect is generated. For graphene, it was found that incorporation of a point defect results in a semiconductor–semimetal transition and also increases notably its polar character. As with graphene, the formation of a point defect in a hexagonal boron nitride sheet reduces its energy gap, although its influence on the resulting dipole moment is not as dramatic as in graphene. The influence of point defects on the structural and electronic properties of graphene oxide and boron nitride oxide sheets were found to be mediated by the chemisorbed species.     

Celecoxib decreases growth and angiogenesis and promotes apoptosis in a tumor cell line resistant to chemotherapy

Background

During the last few years it has been shown in several laboratories that Celecoxib (Cx), a non-steroidal anti-inflammatory agent (NSAID) normally used for pain and arthritis, mediates antitumor and antiangiogenic effects. However, the effects of this drug on a tumor cell line resistant to chemotherapeutical drugs used in cancer have not been described.Herein we evaluate the angiogenic and antitumor effects of Cx in the development of a drug-resistant mammary adenocarcinoma tumor (TA3-MTXR).

Results

Cx reduces angiogenesis in the chick embryonic chorioallantoic membrane assay (CAM), inhibits the growth and microvascular density of the murine TA3-MTXR tumor, reduces microvascular density of tumor metastases, promotes apoptosis and reduces vascular endothelial growth factor (VEGF) production and cell proliferation in the tumor.

Conclusion

The antiangiogenic and antitumor Cx effects correlate with its activity on other tumor cell lines, suggesting that Prostaglandins (PGs) and VEGF production are involved. These results open the possibility of using Celecoxib combined with other experimental therapies, ideally aiming to get synergic effects.