Physiological and Biochemical Aspects of Symbiotic Nitrogen Fixation in Cowpea (Vigna unguiculata (L.) Walp. var. Tuy) Plants Infected by Cowpea Mosaic Virus

Three-day-old cowpea seedlings were inoculated with the severestrain of Cowpea Mosaic Virus (CpMV) and 24 h later with Bradyrhizobiumsp. cowpea, strain I-125, when virus translocation to rootsstill had not taken place. Plants were harvested at 22, 30,45 and 59 d after germination. Active virus replication wasassociated with increased protein content, detected in the leavesof 22-d-old plants. CpMV infection reduced the total leaf area,dry weight of shoots and the chlorophyll content of the firsttrifoliolate leaf at all experimental times. Low sugar contentwas recorded in leaves of 22- and 30-d-old CpMV-infected plantsand in nodules and roots of 30- and 45-d-old CpMV-infected plants.Up to 45 d, the nodule mass of CpMV-infected plants was lowerthan in controls, but reached control values at the 4th harvest.In CpMV-infected nodules, massive agglomeration of virus particles,crystalline virus inclusions and the proliferation of the endoplasmicreticulum were observed only in those cells containing bacteroids.In 30- and 45-d-old plants, CpMV infection decreased the contentof ureides in nodules, roots, and petioles. Virus infectiondid not alter the -amino-N content of roots and nodules butinduced a transient 74% reduction in the level of -amino-N inpetioles of 45-d-old plants. At the 1st and 2nd harvests theactivity of uricase (EC 1.7.3.3 [EC] ) in the nodules and of pyruvatekinase (EC 2.7.1.40 [EC] ) in the nodules and leaves were decreasedseverely by virus infection. CpMV did not hinder the allantoinase(EC 3.5.2.5 [EC] ) activity in the leaves but caused a 9% transitorydecrease in the activity of this enzyme in nodules of 45-d-oldplants. Measurements of NAD-malic enzyme (EC 1.1.1.38 [EC] ) in nodulesalso showed the non-effect of CpMV on this enzyme, except fora temporary 16% reduction at the 2nd harvest. As compared tocontrols, the relative abundance of ureides in 30-d-old CpMV-infectedplants indicated a 15%, 10%, and 51% reduction in the nodules,roots, and petioles, respectively. Results indicate that atthe time of the 4th harvest the symbiotic process, measuredin terms of ureide content and enzymatic activities, was functioningat a near normal level despite nodule infection by CpMV. Key words: Cowpea Mosaic Virus, nitrogen fixation, cowpea, enzymes, ultrastructure     

Levels of IL-17F and IL-33 correlate with HLA-DR activation in clinical-grade human bone marrow–derived multipotent mesenchymal stromal cell expansion cultures

Background aims

Multipotent mesenchymal stromal cell (MSC)-based medicines are extensively investigated for use in regenerative medicine and immunotherapy applications. The International Society for Cell and Gene Therapy (ISCT) proposed a panel of cell surface molecules for MSC identification that includes human leukocyte antigen (HLA)-DR as a negative marker. However, its expression is largely unpredictable despite production under tightly controlled conditions and compliance with current Good Manufacturing Practices. Herein, we report the frequency of HLA-DR expression in 81 batches of clinical grade bone marrow (BM)-derived MSCs and investigated its impact on cell attributes and culture environment.

The balancing act of AKT in T cells

The serine/threonine-specific protein kinase AKT is gaining recognition as a major crossroad in numerous cellular signaling pathways through its ability to regulate cell differentiation, proliferation, survival and metabolism. This review focuses on the recent advances in AKT signaling and downstream events in T cells, emphasizing its contrasting role in conventional and regulatory (Treg) Tcell populations. Activation of AKT has been known for many years to be critical in the development and function of conventional Tcells. However, it has just recently been uncovered that AKTexerts an inhibitory effect on Treg generation and suppressor function. These studies have placed AKTat the nexus of Treg development and function, thus opening novel avenues for therapeutic manipulation.     

Do pollen feeding,pupal‐mating and larval gregariousness have a single origin in Heliconius butterflies? Inferences from multilocus DNA sequence data

Phylogenetic information is useful in understanding the evolutionary history of adaptive traits. Here, we present a well-resolved phylogenetic hypothesis for Heliconius butterflies and related genera. We use this tree to investigate the evolution of three traits, pollen feeding, pupal-mating behaviour and larval gregariousness. Phylogenetic relationships among 60 Heliconiina species (86% of the subtribe) were inferred from partial DNA sequences of the mitochondrial genes cytochrome oxidase I , cytochrome oxidase II and 16S rRNA, and fragments of the nuclear genes elongation factor-1α , apterous , decapentaplegic and wingless (3834 bp in total). The results corroborate previous hypotheses based on sequence data in showing that Heliconius is paraphyletic, with Laparus doris and Neruda falling within the genus, demonstrating a single origin for pollen feeding but with a loss of the trait in Neruda . However, different genes are not congruent in their placement of Neruda ; therefore, monophyly of the pollen feeding species cannot be ruled out. There is also a highly supported monophyletic 'pupal-mating clade' suggesting that pupal mating behaviour evolved only once in the Heliconiina. Additionally, we observed at least three independent origins for larval gregariousness from a solitary ancestor, showing that gregarious larval behaviour arose after warning coloration.  © 2007 The Linnean Society of London, Biological Journal of the Linnean Society , 2007, 92 , 221–239.     

Ten informative markers developed from WRKY sequences in coconut (Cocos nucifera)

Coconut (Cocos nucifera L.) WRKY sequences containing single nucleotide polymorphisms (SNPs) and one microsatellite repeat were used to develop 10 informative markers. These markers were evaluated in 15 genotypes representing six coconut cultivars. SNP‐containing alleles were detected by single‐strand conformation polymorphism (SSCP) analysis. The number of detected alleles ranged from two to four. Five pairs of loci were in linkage disequilibrium in the test population. These markers are currently being evaluated in more individuals/cultivars to determine their value in estimating the genetic diversity of this species.     

Population fluctuations of the house mouse in a Peruvian loma and the functional response of burrowing owls

Abstract In this study, we show that the house mouse (Mus musculus) is the most abundant small mammal in the National Reserve of Lachay in central Peru, and that its large population fluctuations are independent of seasonality. Also, we found that M. musculus is the main small mammal prey of burrowing owls (Athene cunicularia) in Lachay, and that owls respond functionally to mouse abundance. In addition, vegetation cover seems to have a strong effect on small mammal predation by burrowing owls, and possibly other predators such as eagles and foxes. We propose the hypothesis that burrowing owls in arid environments can survive several months eating only arthropods, but that their reproduction is synchronized with a highly nutritious diet, provided by small mammal consumption. The principal prediction of this alternative prey hypothesis is now supported by our data from a tropical ecosystem.