Rising from the sea: correlations between sulfated polysaccharides and salinity in plants

High salinity soils inhibit crop production worldwide and represent a serious agricultural problem. To meet our ever-increasing demand for food, it is essential to understand and engineer salt-resistant crops. In this study, we evaluated the occurrence and function of sulfated polysaccharides in plants. Although ubiquitously present in marine algae, the presence of sulfated polysaccharides among the species tested was restricted to halophytes, suggesting a possible correlation with salt stress or resistance. To test this hypothesis, sulfated polysaccharides from plants artificially and naturally exposed to different salinities were analyzed. Our results revealed that the sulfated polysaccharide concentration, as well as the degree to which these compounds were sulfated in halophytic species, were positively correlated with salinity. We found that sulfated polysaccharides produced by Ruppia maritima Loisel disappeared when the plant was cultivated in the absence of salt. However, subjecting the glycophyte Oryza sativa Linnaeus to salt stress did not induce the biosynthesis of sulfated polysaccharides but increased the concentration of the carboxylated polysaccharides; this finding suggests that negatively charged cell wall polysaccharides might play a role in coping with salt stress. These data suggest that the presence of sulfated polysaccharides in plants is an adaptation to high salt environments, which may have been conserved during plant evolution from marine green algae. Our results address a practical biological concept; additionally, we suggest future strategies that may be beneficial when engineering salt-resistant crops.     

Snake population venomics and antivenomics of Bothrops atrox: Paedomorphism along its transamazonian dispersal and implications of geographic venom variability on snakebite management

We describe two geographically differentiated venom phenotypes across the wide distribution range of Bothrops atrox, from the Colombian Magdalena Medio Valley through Puerto Ayacucho and El Paují, in the Venezuelan States of Amazonas and Orinoquia, respectively, and S?o Bento in the Brazilian State of Maranh?o. Colombian and Venezuelan venoms show an ontogenetic toxin profile phenotype whereas Brazilian venoms exhibit paedomorphic phenotypes. Venoms from each of the 16 localities sampled contain both population-specific toxins and proteins shared by neighboring B. atrox populations. Mapping the molecular similarity between conspecific populations onto a physical map of B. atrox range provides clues for tracing dispersal routes that account for the current biogeographic distribution of the species. The proteomic pattern is consistent with a model of southeast and southwest dispersal and allopatric fragmentation northern of the Amazon Basin, and trans-Amazonian expansion through the Andean Corridor and across the Amazon river between Monte Alegre and Santarém. An antivenomic approach applied to assess the efficacy towards B. atrox venoms of two antivenoms raised in Costa Rica and Brazil using Bothrops venoms different than B. atrox in the immunization mixtures showed that both antivenoms immunodepleted very efficiently the major toxins (PIII-SVMPs, serine proteinases, CRISP, LAO) of paedomorphic venoms from Puerto Ayacucho (Venezuelan Amazonia) through S?o Bento, but had impaired reactivity towards PLA(2) and P-I SVMP molecules abundantly present in ontogenetic venoms. The degree of immunodepletion achieved suggests that each of these antivenoms may be effective against envenomations by paedomorphic, and some ontogenetic, B. atrox venoms.     

Multiple events of horizontal transfer of the Minos transposable element between Drosophila species

In this study the Minos element was analyzed in 26 species of the repleta group and seven species of the saltans group of the genus Drosophila. The PCR and Southern blot analysis showed a wide occurrence of the Minos transposable element among species of the repleta and the saltans groups and also a low number of insertions in both genomes. Three different analyses, nucleotide divergence, historical associations, and comparisons between substitution rates (d(N) and d(S)) of Minos and Adh host gene sequences, suggest the occurrence of horizontal transfer between repleta and saltans species. These data reinforce and extend the Arca and Savakis [Genetica 108 (2000) 263] results and suggest five events of horizontal transfer to explain the present Minos distribution: between D. saltans and the ancestor of the mulleri and the mojavensis clusters; between D. hydei and the ancestor of the mulleri and the mojavensis clusters; between D. mojavensis and D. aldrichi; between D. buzzatii and D. serido; and between D. spenceri and D. emarginata. An alternative explanation would be that repeated events of horizontal transfer involving D. hydei, which is a cosmopolitan species that diverged from the others repleta species as long as 14Mya, could have spread Minos within the repleta group and to D. saltans. The data presented in this article support a model in which distribution of Minos transposon among Drosophila species is determined by horizontal transmission balanced by vertical inactivation and extinction.     

Maternal and cord blood levels of serum amyloid A, C-reactive protein, tumor necrosis factor-alpha, interleukin-1beta, and interleukin-8 during and after delivery

C-reactive protein (CRP) and serum amyloid A (SAA) are acute-phase proteins mainly synthesized by the liver in response to some cytokines. They are potentially useful to diagnosing infection and monitoring different clinical conditions. The aim of this study was to measure SAA and CRP in maternal and cord blood during and after delivery and try to correlate these proteins with tumor necrosis factor-alpha, interleukin-1beta, and interleukin-8. Acute-phase proteins and cytokines were measured by ELISA in 24 healthy pregnant women undergoing vaginal delivery or Cesarean section. Cord blood samples in addition to maternal blood were collected. SAA and CRP reached the maximum maternal serum levels 24 hours after delivery, while cytokines remained constant over time. SAA and CRP were significantly higher in maternal serum than in newborn's (P< .001) at the moment of delivery. SAA and CRP, regardless of the type of delivery, reproduce the common pattern observed in most inflammatory conditions. Proinflammatory cytokine serum levels do not mirror the increase in SAA and CRP levels.     

Genetic characterization of European-Zebu composite bovine using RFLP markers

A population of 370 European-Zebu composite beef heifers, consisting of six different breed compositions (A-F), were characterized genetically, using RFLP markers of luteinizing hormone receptor (LHR) and follicle-stimulating hormone receptor (FSHR) genes. Our objectives were to genetically characterize this population and to determine the structure and the genetic variability of this hybrid herd. The genotypes were determined through PCR, followed by digestion with restriction endonucleases. The PCR-RFLP analysis made it possible to identify the LHR and FSHR genotypes, as well as to characterize the degree of heterozygosis, which was high for all of the breed compositions, for both loci, except for two combinations for LHR (B and C). The observed heterozygosity (Ho) was lower than the expected heterozygosity (He) for compositions C (for LHR) and A and D (for FSHR); however, for the population as a whole, Ho was above He (with a mean of 57 versus 46%, respectively), reflecting the elevated genetic variability in this population and also the informative value of the RFLP markers, which could be useful for population genetic characterization studies. The analysis of the degree of genetic structure of this population, estimated by the Nei's statistic, for both loci, indicated an elevated total genetic diversity (HT = 47%), with most of this variability being due to intrapopulational diversity (HS = 46%), with a low degree of genetic differentiation among the six breed compositions (GST = 1.2%). The estimates generated by the Wright's F statistic indicated a non-endogamic population, with excess heterozygotes (FIT = -0.22), which was also observed at the intrapopulational level (FIS = -0.23). The results gave evidence that the genetic selection applied to this European-Zebu composite population did not affect the expected high genetic variability for this type of crossbreeding, which makes it possible to use these animals to obtain economically valuable productive and reproductive traits.     

Lectin KM+-induced neutrophil haptotaxis involves binding to laminin

The lectin KM+ from Artocarpus integrifolia, also known as artocarpin, induces neutrophil migration by haptotaxis. The interactions of KM+ with both the extracellular matrix (ECM) and neutrophils depend on the lectin ability to recognize mannose-containing glycans. Here, we report the binding of KM+ to laminin and demonstrate that this interaction potentiates the KM+-induced neutrophil migration. Labeling of lung tissue by KM+ located its ligands on the endothelial cells, in the basement membrane, in the alveolus, and in the interstitial connective tissue. Such labeling was inhibited by 400 mM D-mannose, 10 mM Manalpha1-3[Manalpha1-6]Man or 10 microM peroxidase (a glycoprotein-containing mannosyl heptasaccharide). Laminin is a tissue ligand for KM+, since both KM+ and anti-laminin antibodies not only reacted with the same high molecular mass components of a lung extract, but also determined colocalized labeling in basement membranes of the lung tissue. The relevance of the KM+-laminin interaction to the KM+ property of inducing neutrophil migration was evaluated. The inability of low concentrations of soluble KM+ to induce human neutrophil migration was reversed by coating the microchamber filter with laminin. So, the interaction of KM+ with laminin promotes the formation of a substrate-bound KM+ gradient that is able to induce neutrophil haptotaxis.     

Heme Amplifies the Innate Immune Response to Microbial Molecules through Spleen Tyrosine Kinase (Syk)-dependent Reactive Oxygen Species Generation

Infectious diseases that cause hemolysis are among the most threatening human diseases, because of severity and/or global distribution. In these conditions, hemeproteins and heme are released, but whether heme affects the inflammatory response to microorganism molecules remains to be characterized. Here, we show that heme increased the lethality and cytokine secretion induced by LPS in vivo and enhanced the secretion of cytokines by macrophages stimulated with various agonists of innate immune receptors. Activation of nuclear factor κB (NF-κB) and MAPKs and the generation of reactive oxygen species were essential to the increase in cytokine production induced by heme plus LPS. This synergistic effect of heme and LPS was blocked by a selective inhibitor of spleen tyrosine kinase (Syk) and was abrogated in dendritic cells deficient in Syk. Moreover, inhibition of Syk and the downstream molecules PKC and PI3K reduced the reactive oxygen species generation by heme. Our results highlight a mechanism by which heme amplifies the secretion of cytokines triggered by microbial molecule activation and indicates possible pathways for therapeutic intervention during hemolytic infectious diseases.     

Genetic transformation of Rangpur lime (Citrus limonia osbeck) with thebO (bacterio-opsin) genen and its initial evaluation forPhytophthora nicotianae resistance

Transgenic plants expressing the bacterio-opsin (bO) gene can spontaneously activate programmed cell death (ped) and may enhance broad-spectrum pathogen resistance by activating an intrinsic defense pathway in plant species such as tobacco and potato. In this work, we produced transgenic Rangpur lime plants with thebO gene, viaAgrobacterium tumefaciens-mediated transformation, and evaluated these plants forPhytophthora nicotianae resistance. Two transgenic lines were successfully regenerated and transformation was confirmed by GUS activity assay, PCR analysis, Southern, Northern and Western blot analyses, in addition to detecting the expressed bO protein by an immunological approach. Evaluation forPhytophthora nicotianae resistance was carried out by plant inoculations with the pathogen and quantification of the affected area. One of the two transgenic lines showed greater tolerance to the fungal pathogen as compared to the control, with significantly smaller stem lesions after pathogen challenge. This increase in pathogen tolerance is correlated with a significantly higher level of transgene expression in this line when compared with the other transgenic line. This is the first report of the introduction of a potentially important gene into Rangpur lime to provide novel pathogen tolerance.