Postnatal maturation in nitric oxide-induced pulmonary artery relaxation involving cyclooxygenase-1 activity

The maturation in the vasodilator response to nitric oxide (NO) in isolated intrapulmonary arteries was analyzed in newborns and 15- to 20-day-old piglets. The vasodilator responses to NO gas but not to the NO donor sodium nitroprusside increased with age. The inhibitory effects of the superoxide dismutase inhibitor diethyldithiocarbamate and xanthine oxidase plus hypoxanthine and the potentiation induced by superoxide dismutase and MnCl(2) of NO-induced vasodilatation were similar in the two age groups. Diphenyleneiodonium (NADPH oxidase inhibitor) potentiated the response to NO, and this effect was more pronounced in the older animals. The nonselective cyclooxygenase inhibitors indomethacin and meclofenamate and the preferential cyclooxygenase-1 inhibitor aspirin augmented NO-induced relaxation specifically in newborns, whereas the selective cycloxygenase-2 inhibitor NS-398 had no effect. The expressions of alpha-actin, cycloxygenase-1, and cycloxygenase-2 proteins were similar, whereas Cu,Zn-superoxide dismutase decreased with age. Therefore, the present data suggest that the maturational increase in the vasodilatation of NO in the pulmonary arteries during the first days of extrauterine life involves a cycloxygenase-dependent inhibition of neonatal NO activity.     

Revision of the taxonomic position of the xylanolytic Bacillus sp. MIR32 reidentified as Bacillus halodurans and plasmid-mediated transformation of B. halodurans

Bacillus sp. MIR32 has been isolated using xylan as the only carbon source, and one of its xylanolytic enzymes has been extensively studied. Biochemical analysis first related this strain to Bacillus amyloliquefaciens, but further studies based on a comparison of 16S rDNA sequences, G+C content, and DNA-DNA hybridization showed that strain MIR32 should be classified as a member of the species Bacillus halodurans. This change is also supported by the typical phenotype observed and by the results of PCR amplification directed toward spacers in rDNA and tDNA genes, which were assayed and compared with those of B. halodurans DSM 497(T). Although among alkaliphilic bacilli competence development has not been experimentally demonstrated, in this work both B. halodurans MIR32 and DSM 497(T) were transformed according to a simple procedure developed in our laboratory, reaching 10(2)-10(3) stable transformants per microgram of plasmid DNA.     

Effect of inoculation with putative plant growth-promoting rhizobacteria isolated from Pinus spp. on Pinus pinea growth, mycorrhization and rhizosphere microbial communities

Aims: In this study, 10 putative plant growth-promoting rhizobacteria (PGPR) were assayed for their ability to improve Pinus pinea growth and mycorrhization. Methods and Results: After an inoculation assay, except for two, all strains stimulated plant growth. All bacteria altered rhizosphere microbial communities as revealed by phospholipid fatty acid analysis; associating plant growth promotion with a decrease in biological diversity. Three strains were tested for their ability to enhance pine mycorrhization with wild fungi species. Only strain BB1 increased the total number of mycorrhizal root tips. Mycorrhizas present in the roots of each treatment were identified by ribosomal RNA sequencing and denaturing gradient gel electrophoresis analysis, detecting specificity between mycorrhizal species colonizing the roots and the inoculated PGPR. Conclusions: In conclusion, BB1 appears to be a good candidate to be developed into a biofertilizer directed to enhance pine growth and mycorrhization, which should result in a better establishment rate for plants used in reforestation. Significance and Impact of the Study: This study shows the potential of PGPR to improve fitness of forest tree specie. Moreover, the specificity between the bacteria inoculated and the mycorrhiza that the plant selects involve a potential biotechnological use in production of value-added fungi.     

A new species of Heteromyoxyuris (Nematoda: Oxyuridae), parasite of Perognathus flavus (Rodentia: Heteromyidae) from Mexico

Heteromyoxyuris otomii n. sp., which inhabits the intestinal caecum of Perognathus flavus (Heteromyidae), in Zaragoza, Hidalgo, Mexico, is described. This new species differs from the 2 other congeneric species in the morphology and length of lateral alae in males. Heteromyoxyuris deserti has simple lateral alae located at both sides of the body, whereas in the new species, these structures are double at both sides; in contrast, lateral alae of Heteromyoxyuris longejector begin at the posterior half of the body, whereas they arise in the first third in the new species. Heteromyoxyuris longejector was found in 2 new host species, i.e., Perognathus amplus and Chaetodipus hispidus. This record represents the first record for the species in Mexico, increasing its geographic distribution.     

Hyperdominance in fruit production in the Brazilian Atlantic rain forest: the functional role of plants in sustaining frugivores

The availability of fruits is critical for tropical forests, where the majority of plant species rely upon animal vectors for seed dispersal. However, we do not know how fruit production is temporally distributed over species and families. Two plant families are particularly important in floristic inventories of Atlantic rain forests: Arecaceae, a few species of which are highly abundant; and Myrtaceae, which is abundant and displays outstanding species diversity. In this context, we asked whether hyperdominance occurs in fruit production in the Atlantic rain forest, and whether it occurs in the abundant species of Arecaceae and Myrtaceae. We investigated whether the temporal fruit production patterns differ between Myrtaceae, Arecaceae, and the plant community as a whole. We also applied a functional dispersion index to assess the temporal fruit diversity over a 2‐yr period, with regard to morphological and phenological traits. We found that the phenomenon of hyperdominance occurs in fruit production: five species accounted for more than half of the pulp biomass. Arecaceae fruit biomass peaked at the end of wet season, overlapping with the community peak; whereas Myrtaceae species fruited throughout the year and were an important resource during periods of food scarcity. Myrtaceae filled more of the fruit morphospace over time because their fruits exhibit a large range of morphologies and phenological strategies. Our results demonstrated the importance of combining phenology and fruit morphology in the evaluation of resource availability, which revealed periods of high fruit diversity that could support a range of frugivore sizes and maintain overall ecosystem functionality.     

Human RIF1 and protein phosphatase 1 stimulate DNA replication origin licensing but suppress origin activation

The human RIF1 protein controls DNA replication, but the molecular mechanism is largely unknown. Here, we demonstrate that human RIF1 negatively regulates DNA replication by forming a complex with protein phosphatase 1 (PP1) that limits phosphorylation‐mediated activation of the MCM replicative helicase. We identify specific residues on four MCM helicase subunits that show hyperphosphorylation upon RIF1 depletion, with the regulatory N‐terminal domain of MCM4 being particularly strongly affected. In addition to this role in limiting origin activation, we discover an unexpected new role for human RIF1‐PP1 in mediating efficient origin licensing. Specifically, during the G1 phase of the cell cycle, RIF1‐PP1 protects the origin‐binding ORC1 protein from untimely phosphorylation and consequent degradation by the proteasome. Depletion of RIF1 or inhibition of PP1 destabilizes ORC1, thereby reducing origin licensing. Consistent with reduced origin licensing, RIF1‐depleted cells exhibit increased spacing between active origins. Human RIF1 therefore acts as a PP1‐targeting subunit that regulates DNA replication positively by stimulating the origin licensing step, and then negatively by counteracting replication origin activation.     

Defining the importance of landscape metrics for large branchiopod biodiversity and conservation: the case of the Iberian Peninsula and Balearic Islands

The deficiency in the distributional data of invertebrate taxa is one of the major impediments acting on the bias towards the low awareness of its conservation status. The present study sets a basic framework to understand the large branchiopods distribution in the Iberian Peninsula and Balearic Islands. Since the extensive surveys performed in the late 1980s, no more studies existed updating the information for the whole studied area. The present study fills the gap, gathering together all available information on large branchiopods distribution since 1995, and analysing the effect of human population density and several landscape characteristics on their distribution, taking into consideration different spatial scales (100 m, 1 km and 10 km). In overall, 28 large branchiopod taxa (17 anostracans, 7 notostracans and 4 spinicaudatans) are known to occur in the area. Approximately 30% of the sites hosted multiple species, with a maximum of 6 species. Significant positive co-occurring species pairs were found clustered together, forming 4 different associations of large branchiopod species. In general, species clustered in the same group showed similar responses to analysed landscape characteristics, usually showing a better fit at higher spatial scales.