Oligodendrocyte progenitor cells proliferate and survive in an immature state following treatment with an axolemma-enriched fraction

The ability of an AEF (axolemma-enriched fraction) to influence the proliferation, survival and differentiation of OPC (oligodendrocyte progenitor cells) was evaluated. Following addition of AEF to cultured OPC, the AEF associated with the outer surface of OPC so that subsequent metabolic events were likely mediated by direct AEF-OPC contact. Addition of AEF to the cultured OPC resulted in a dose- and time-dependent increase in proliferation that was partially dependent on Akt (protein kinase B) and MAPK (mitogen-activated protein kinase) activation. The major mitogen in an AEF-SE (soluble 2.0 M NaCl extract of the AEF) was identified as aFGF (acidic fibroblast growth factor) and accounted for 50% of the mitogenicity. The remaining 50% of the mitogenicity had properties consistent with bFGF (basic fibroblast growth factor) but was not unequivocally identified. Under conditions that limit the survival of OPC in culture, AEF treatment prolonged the survival of the OPC. Antigenic and morphological examination of the AEF-treated OPC indicated that the AEF treatment helped the OPC survive in a more immature state. The potential downstream metabolic pathways potentially activated in OPC by AEF and the consequences of these activated pathways are discussed. The results of these studies are consistent with the view that direct contact of axons with OPC stimulates their proliferation and survival while preventing their differentiation.     

Agrobacterium rhizogenes transformation of the Phaseolus spp.: a tool for functional genomics

A fast, reproducible, and efficient transformation procedure employing Agrobacterium rhizogenes was developed for Phaseolus vulgaris L. wild accessions, landraces, and cultivars and for three other species belonging to the genus Phaseolus: P. coccineus, P. lunatus, and P. acutifolius. Induced hairy roots are robust and grow quickly. The transformation frequency is between 75 and 90% based on the 35-S promoter-driven green fluorescent protein and beta-glucuronidase expression reporter constructs. When inoculated with Rhizobium tropici, transgenic roots induce normal determinate nodules that fix nitrogen as efficiently as inoculated standard roots. The A. rhizogenes-induced hairy root transformation in the genus Phaseolus sets the foundation for functional genomics programs focused on root physiology, root metabolism, and root-microbe interactions.     

Non-heme Iron as Ferrous Sulfate Does Not Interact with Heme Iron Absorption in Humans

The absorption of heme iron has been described as distinctly different from that of non-heme iron. Moreover, whether heme and non-heme iron compete for absorption has not been well established. Our objective was to investigate the potential competition between heme and non-heme iron as ferrous sulfate for absorption, when both iron forms are ingested on an empty stomach. Twenty-six healthy nonpregnant women were selected to participate in two iron absorption studies using iron radioactive tracers. We obtained the dose?Cresponse curve for absorption of 0.5, 10, 20, and 50?mg heme iron doses, as concentrated red blood cells. Then, we evaluated the absorption of the same doses, but additionally we added non-heme iron, as ferrous sulfate, at constant heme/non-heme iron molar ratio (1:1). Finally, we compare the two curves by a two-way ANOVA. Iron sources were administered on an empty stomach. One factor analysis showed that heme iron absorption was diminished just by increasing total heme iron (P?<?0.0001). The addition of non-heme iron as ferrous sulfate did not have any effect on heme iron absorption (P?=?NS). We reported evidence that heme and non-heme iron as ferrous sulfate does not compete for absorption. The mechanism behind the absorption of these iron sources is not clear.     

Reducing endoplasmic reticulum stress does not improve steatohepatitis in mice fed a methionine- and choline-deficient diet

Endoplasmic reticulum (ER) stress has been implicated in the pathogenesis of nonalcoholic steatohepatitis. The ER stress response is activated in the livers of mice fed a methionine- and choline-deficient (MCD) diet, yet the role of ER stress in the pathogenesis of MCD diet-induced steatohepatitis is unknown. Using chemical chaperones on hepatic steatosis and markers of inflammation and fibrosis in mice fed a MCD diet, we aim to determine the effects of reducing ER stress. C57BL/6J mice were fed a MCD diet with or without the ER chemical chaperones 4-phenylbutyric acid (PBA) and tauroursodeoxycholic acid (TUDCA) for 2 wk. TUDCA and PBA effectively attenuated the ER stress response in MCD diet-fed mice, as evidenced by reduced protein levels of phosphorylated eukaryotic initiation factor 2α and phosphorylated JNK and suppression of mRNA levels of CCAAT/enhancer binding protein homologous protein, glucose-regulated protein 78 kDa, and X-box binding protein 1. However, PBA and TUDCA did not decrease MCD diet-induced hepatic steatosis. MCD diet-induced hepatic inflammation, as evidenced by increased plasma alanine aminotransferase and induction of hepatic TNFα expression, was also not reduced by PBA or TUDCA. PBA and TUDCA did not attenuate MCD diet-induced upregulation of the fibrosis-associated genes tissue inhibitor of metalloproteinase-1 and matrix metalloproteinase-9. ER chemical chaperones reduce MCD diet-induced ER stress, yet they do not improve MCD diet-induced hepatic steatosis, inflammation, or activation of genes associated with fibrosis. These data suggest that although the ER stress response is activated by the MCD diet, it does not have a primary role in the pathogenesis of MCD diet-induced steatohepatitis.     

Oral Administration of Lactobacillus Strains Isolated from Breast Milk as an Alternative for the Treatment of Infectious Mastitis during Lactation

In this study, 20 women with staphylococcal mastitis were randomly divided in two groups. Those in the probiotic group daily ingested 10 log₁₀ CFU of Lactobacillus salivarius CECT5713 and the same quantity of Lactobacillus gasseri CECT5714 for 4 weeks, while those in the control one only ingested the excipient. Both lactobacillus strains were originally isolated from breast milk. On day 0, the mean staphylococcal counts in the probiotic and control groups were similar (4.74 and 4.81 log₁₀ CFU/ml, respectively), but lactobacilli could not be detected. On day 30, the mean staphylococcal count in the probiotic group (2.96 log₁₀ CFU/ml) was lower than that of the control group (4.79 log₁₀ CFU/ml). L. salivarius CECT5713 and L. gasseri CECT5714 were isolated from the milk samples of 6 of the 10 women of the probiotic group. At day 14, no clinical signs of mastitis were observed in the women assigned to the probiotic group, but mastitis persisted throughout the study period in the control group women. In conclusion, L. salivarius CECT5713 and L. gasseri CECT5714 appear to be an efficient alternative for the treatment of lactational infectious mastitis during lactation.     

Signaling lymphocytic activation molecule expression and regulation in human intracellular infection correlate with Th1 cytokine patterns.

Induction of Th1 cytokines, those associated with cell-mediated immunity, is critical for host defense against infection by intracellular pathogens, including mycobacteria. Signaling lymphocytic activation molecule (SLAM, CD150) is a transmembrane protein expressed on lymphocytes that promotes T cell proliferation and IFN-gamma production. The expression and role of SLAM in human infectious disease were investigated using leprosy as a model. We found that SLAM mRNA and protein were more strongly expressed in skin lesions of tuberculoid patients, those with measurable CMI to the pathogen, Mycobacterium leprae, compared with lepromatous patients, who have weak CMI against M. leprae. Peripheral blood T cells from tuberculoid patients showed a striking increase in the level of SLAM expression after stimulation with M. leprae, whereas the expression of SLAM on T cells from lepromatous patients show little change by M. leprae stimulation. Engagement of SLAM by an agonistic mAb up-regulated IFN-gamma production from tuberculoid patients and slightly increased the levels of IFN-gamma in lepromatous patients. In addition, IFN-gamma augmented SLAM expression on M. leprae-stimulated peripheral blood T cells from leprosy patients. Signaling through SLAM after IFN-gamma treatment of Ag-stimulated cells enhanced IFN-gamma production in lepromatous patients to the levels of tuberculoid patients. Our data suggest that the local release of IFN-gamma by M. leprae-activated T cells in tuberculoid leprosy lesions leads to up-regulation of SLAM expression. Ligation of SLAM augments IFN-gamma production in the local microenvironment, creating a positive feedback loop. Failure of T cells from lepromatous leprosy patients to produce IFN-gamma in response to M. leprae contributes to reduced expression of SLAM. Therefore, the activation of SLAM may promote the cell-mediated immune response to intracellular bacterial pathogens.     

Population structure of the black arowana (Osteoglossum ferreirai) in Brazil and Colombia: implications for its management

In regions with high biodiversity, where species are exploited as a source of income, it is essential to learn more about the species that are being commercialized. For the ornamental fish black arowana (Osteoglossum ferreirai), distributed only in Colombia and Brazil, there is currently a lack of information about population estimates in each location, genetic data and lastly, about the events that lead to the current distribution of the species. A genetic population study was conducted by sequencing the mitochondrial genes cytochrome b and ATPase 6, and genotyping of eight microsatellite loci. Mitochondrial gene results indicated the absence of variable sites, and the microsatellite results showed a significantly lower heterozygosity than expected demonstrating that currently the genetic diversity of the species is low. The fact that this species is been exploited and that it shows low genetic diversity means it can quickly become endangered. For this reason, conservation, management and use programs for the black arowana should include and consider the genetic data obtained as well as additional life history and ecological factors to promote its sustainable use.     

Dinitrogen fixation and infection of grass leaves byPseudomonas rubrisubalbicans andHerbaspirillum seropedicae

Bacteria causing mottled stripe disease in sugar cane, known asPseudomonas rubrisubalbicans, were shown to be able to fix molecular N₂ and to grow on it. The root associated diazotroph known asHerbaspirillum seropedicae, after artificial inoculation caused mottled stripe disease symptoms on sorghum and Napier grass but not on sugar cane. Both bacteria could be reisolated from leaves even 60 days after. Sugar cane leaves contained large numbers of these bacteria even in the uninoculated controls. Additional physiological characteristics of six strains ofP. rubrisubalbicans were compared with those of twoH. seropedicae strains and were shown to be very similar.     

Antibiotic production by Pseudomonas reptilivora as a phage conversion

The ability of Pseudomonas reptilivora to produce three broad-spectrum antimicrobial substances is easily lost when bacteria are subcultured. The study of the antibiotic production under defined culture conditions has shown that the biosynthesis of these substances depends upon the presence of a temperature-sensitive temperate phage. Antibiotic production is lost after phage induction.     

Effects of inter-annual temperature variability,including ENSO and post-ENSO events,on reproductive traits in the tunicate Pyura praeputialis

Reproduction in tunicates is considered to be particularly vulnerable to changes in seawater temperature. In the present study we investigated the effects of sea surface temperature and temperature anomalies on reproductive traits of the non-native sessile tunicate Pyura praeputialis. Reproductive traits of this species were investigated over the course of 67 months, based on samples collected at two localities (eastern and western shorelines) of the Bay of Antofagasta. The study period included years with different oceanic and atmospheric conditions: a warm event, El Niño (June 1997 to July 1998); a cold event, La Niña (August 1998 to December 2000); and post-La Niña (January 2000 to December 2002). We compared two common indices (condition and gonadosomatic) and histological sections to evaluate the maximum reproduction index of this introduced species that dominates a large part of the rocky intertidal habitat in the Bay of Antofagasta. We found sexually mature individuals all year-round and a decrease in both reproductive indices matching the reduction in the sea surface temperature during the austral autumn and winter months. The results suggest that gonad development in this species is sensitive to sea surface temperature and thermal anomalies. We conclude that future thermal anomalies or projected global average sea surface warming associated with climate change might have no negative consequences on these reproductive traits of P. praeputialis. This suggests this species is ecologically resilient and that the ecosystem services that this species provides for other invertebrate and algal species will be maintained.