Identification and absolute configuration of dihydroxy-arachidonic acids formed by oxygenation of 5S-HETE by native and aspirin-acetylated COX-2

Biosynthesis of the prostaglandin endoperoxide by the cyclooxygenase (COX) enzymes is accompanied by formation of a small amount of 11R-hydroxyeicosatetraenoic acid (HETE), 15R-HETE, and 15S-HETE as by-products. Acetylation of COX-2 by aspirin abrogates prostaglandin synthesis and triggers formation of 15R-HETE as the sole product of oxygenation of arachidonic acid. Here, we investigated the formation of by-products of the transformation of 5S-HETE by native COX-2 and by aspirin-acetylated COX-2 using HPLC-ultraviolet, GC-MS, and LC-MS analysis. 5S,15S- dihydroxy (di)HETE, 5S,15R-diHETE, and 5S,11R-diHETE were identified as by-products of native COX-2, in addition to the previously described di-endoperoxide (5S,15S-dihydroxy-9S,11R,8S,12S-diperoxy-6E,13E-eicosadienoic acid) as the major oxygenation product. 5S,15R-diHETE was the only product formed by aspirin-acetylated COX-2. Both 5,15-diHETE and 5,11-diHETE were detected in CT26 mouse colon carcinoma cells as well as in lipopolysaccharide-activated RAW264.7 cells incubated with 5S-HETE, and their formation was attenuated in the presence of the COX-2 specific inhibitor, NS-398. Aspirin-treated CT26 cells gave 5,15-diHETE as the most prominent product formed from 5S-HETE. 5S,15S-diHETE has been described as a product of the cross-over of 5-lipoxygenase (5-LOX) and 15-LOX activities in elicited rat mononuclear cells and human leukocytes, and our studies implicate cross-over of the 5-LOX and COX-2 pathways as an additional biosynthetic route.     

Vitamin A as adjuvant to the mouse immune response to pertussis, tetanus and diphtheria vaccines

Vitamin A was used as adjuvant, comparatively with Al(OH)₃, in pertussis, tetanus and diphtheria vaccines. Both groups induced a primary immune response in mice, and one single booster dose elevated the antibodies titers in average 554 times to vitamin A groups and 104 times to Al(OH)₃. These antibodies titers correlate with sera IL-4 in immunized animals, suggesting a Th2 response. Other cytokines detected in the sera and/or lymphocytes culture supernatants (IL-2 and IFN-) indicated that vitamin A could also modulate a Th1 response in DPT and acellular pertussis vaccines.     

Screening for ligninolytic enzymes in autochthonous fungal strains from Argentina isolated from different substrata

The production of different extracellular ligninolytic enzymes was studied in autochthonous fungal strains from Argentina isolated from litter derived from hydrocarbon-polluted sites and from basidiocarps frowing on wood in forests. The strains tested were cultivated in a carbon-limited medium with shaking. Laccase activity reached higher levels than aryl-alcohol oxidase and manganese-dependent peroxidase activities in liquid cultures from different fungi. No lignin peroxidase activity was found in any strain assayed. Some species are reported for the first time as producers of different ligninolytic enzymes.     

Dickkopf-1 antagonizes Wnt signaling independent of beta-catenin in human mesothelioma

Dickkopf-1 (Dkk-1) is a secreted protein that acts as a potent inhibitor of the Wnt signal transduction pathway. It is thought that the antagonistic effect of Dkk-1 is specific to the canonical (Wnt/beta-catenin) pathway. In this study, we demonstrate that restoration of Dkk-1 expression suppresses cell growth and induces apoptotic cell death in beta-catenin-deficient mesothelioma cell lines H28 and MS-1. Furthermore, we found that a small-molecule inhibitor of JNK inhibited the apoptosis induced by Dkk-1 overexpression in these cells. Together, our data suggest that Dkk-1 may be able to antagonize Wnt signaling and exert its tumor suppressive effects through beta-catenin-independent non-canonical pathways (i.e., the Wnt/JNK pathway).     

The Freshwater Mussel (Elliptio complanata) as a Sentinel Species: Vitellogenin and Steroid Receptors

Freshwater mussels, Elliptio complanata were collected froma reference and pollutant-impacted pond on Cape Cod, MA. Glutathione-S-transferase(GST) activity was measured in gill, hepatopancreas and foot.In addition, content of seven heavy metals were measured inwhole bodies. GST activity was significantly elevated in hepatopancreasand foot, as was whole body cadmium level in animals from thecontaminated site suggesting that these animals have been exposedto organic and inorganic contaminants. Sodium dodecyl acrylamidegel electrophoresis (SDS-PAGE) analysis showed putative vitellogeninswith molecular weight 180 and 205 kDa bands only in the ovary.In non-denatured gel electrophoresis ovarian extracts revealedtwo higher molecular weight bands at 550 and 700 kDa, whichwere reproductive stage specific. Western blotting of SDS-PAGEand non-denatured gels using the anti-scallop yolk-protein antibodyconfirmed the presence of cross-reacting bands of the same molecularweights in the ovary but not other tissues. Although severalexperiments involving steroid hormone exposure were done, nosignificant changes in vitellogenin protein levels were observed.However, using an anti-human ERß antibody, ERßpositive bands were observed both in female foot, and the ovary.No cross reactivity with the antibody was observed in hepatopancreas.Additional studies are required to resolve questions of vitellogeninregulation and the role of (xeno)estrogens in bivalve molluscs.     

Genetic relationships among Hylocereus and Selenicereus vine cacti (Cactaceae): evidence from hybridization and cytological studies

BACKGROUND AND AIMS: Hylocereus and Selenicereus are native to tropical and sub-tropical America. Based on its taxonomic status and crossability relations it was postulated that H. megalanthus (syn. S. megalanthus) is an allotetraploid (2n = 4x = 44) derived from natural hybridization between two closely related diploid taxa. The present work aimed at elucidating the genetic relationships between species of the two genera. METHODS: Crosses were performed and the putative hybrids were analysed by chromosome counts and morphological traits. The ploidy level of hybrids was confirmed by fluorescent in situ hybridization (FISH) of rDNA sites. Genomic in situ hybridization (GISH) was used in an attempt to identify the putative diploid genome donors of H. megalanthus and an artificial interploid hybrid. KEY RESULTS: Reciprocal crosses among four diploid Hylocereus species (H. costaricensis, H. monacanthus (syn. H. polyrhizus), H. undatus and Hylocereus sp.) yielded viable diploid hybrids, with regular chromosome pairing. Reciprocal crosses between these Hylocereus spp. and H. megalanthus yielded viable triploid, pentaploid, hexaploid and aneuploid hybrids. Morphological and phenological traits confirm the hybrid origin. In situ detection of rDNA sites was in accord with the ploidy status of the species and hybrid studied. GISH results indicated that overall sequence composition of H. megalanthus is similar to that of H. ocamponis and S. grandiflorus. High sequence similarity was also found between the parental genomes of H. monacanthus and H. megalanthus in one triploid hybrid. CONCLUSIONS: The ease of obtaining partially fertile F1 hybrids and the relative sequence similarity (in GISH study) suggest close genetic relationships among the taxa analysed.     

It Weigh(t)s on You: Everyday Discrimination and Adiposity Among Latinos

Objective

Evidence suggests discrimination increases the risk of obesity. The biopsychosocial model of racism posits that psychological factors such as depressive symptoms may link experiences of perceived interpersonal discrimination to obesity. This study tested whether self‐reported experiences of everyday discrimination were associated with adiposity indicators and whether depressive symptoms explained these associations.

Methods

Cross‐sectional survey data of 602 Latino adults living in Lawrence, Massachusetts, from the Latino Health and Well‐being Project (2011‐2013) were used. Participants completed questionnaires assessing perceived everyday discrimination and depressive symptoms. Anthropometric measures (i.e., BMI and waist circumference [WC]) were obtained by trained staff. Structural equation modeling was employed to test for direct and indirect effects of perceived everyday discrimination on adiposity.

Results

Perceived everyday discrimination was directly and positively associated with higher BMI and WC, independent of sociodemographic factors, physical activity, and stressful life events. Perceived everyday discrimination was not indirectly associated with BMI and WC through depressive symptoms. However, perceived everyday discrimination was associated with higher levels of depressive symptoms.

Conclusions

Self‐reported everyday discrimination among Latino adults is associated with adiposity. Day‐to‐day interpersonal discrimination may be implicated in obesity disparities for Latino adults.

     

Genetic Ablation of miR-33 Increases Food Intake,Enhances Adipose Tissue Expansion,and Promotes Obesity and Insulin Resistance

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Patch identity and the spatial heterogeneity of woody encroachment in exotic-dominated old-field grasslands

Most grassland communities in agricultural landscapes comprise a mix of exotic and native plants, where grasses and forbs are disposed in low diversity patches conforming a heterogeneous matrix of vegetation. Within these “novel” ecosystems, woody encroachment is one of the principal causes of ecosystem degradation. Here, we examined the resistance to exotic woody establishment (Gleditsia triacanthos) into four different monospecific patches characteristics of old-field grasslands in Inland Pampa: an annual forb (Conium maculatum), an annual grass (Lolium multiflorum), and two perennial grasses (Cynodon dactylon and Festuca arundinacea). We evaluated the filter to tree recruitment by rodent seed removal and survival and growth of Gleditsia seedlings transplanted into undisturbed and disturbed microsites, within each patch. Beneath intact vegetation seed removal was an important biotic filter to woody establishment whereas disturbances facilitated seed survival in patches of perennial grasses. Patch identity affected tree growth, and Cynodon reduced the final biomass compared to forbs. Disturbance enhanced tree performance independently of patch type. After 2 years, tree survival was independent of disturbance and patch identity. As patch identity may regulate granivory and growth of tree saplings, community susceptibility or resistance to woody invasion rather than representing a static community attribute could vary according to the dynamic changes in the proportion of susceptible-resistant patches. Broadly, our work reinforces the concept that mechanisms regulating vegetation heterogeneity add a component of stochasticity to biotic resistance to community plant invasion.