Parthenium weed (Parthenium hysterophorus L.) research in Ethiopia: Investigation of pathogens as biocontrol agents

Parthenium is an exotic invasive weed that now occurs widely in Ethiopia. Surveys to determine the presence and distribution of pathogens associated with parthenium and further evaluation of the pathogens found as potential biocontrol agents were carried out in Ethiopia since 1998. Several fungal isolates of the genus Helminthosporium, Phoma, Curvularia, Chaetomium, Alternaria, and Eurotium were obtained from the seeds and other plant parts. However, all of the isolates tested were non-pathogenic except Helminthosporium isolates. The two most important diseases were the rust, Puccinia abrupta var. partheniicola and the phyllody, caused by a phytoplasma belonging to the species “Candidatus Phytoplasma aurantifolia”. Host specificity tests revealed that the rust, P. abrupta, only sporulates on parthenium while the phyllody infected parthenium, groundnut, sesame, grass pea, lentil, and chickpea. Suspected insect vectors were examined for phytoplasma infection by means of Polymerase Chain Reaction (PCR). The successful acquisition of phytoplasma’s by the leafhopper, Orosius cellulosus Lindberg (Cicadellidae), was determined by molecular detection of phytoplasma. Phytoplasma was also detected from a single bait plant after feeding by the leafhopper. Sequencing data from phytoplasma obtained from parthenium and the above mentioned crops was identical with sequence identities > 98%. The rust was commonly found at 1400 – 2500 m.a.s.l. with disease incidence up to 100% in some locations while phyllody was observed at 900 – 2300 m.a.s.l. with incidence up to 75%. Individual effects of the rust and phyllody diseases on Parthenium in different locations under field condition showed significant reduction on seed and morphological parameters. Seed production was reduced by 42 and 85% due to rust and phyllody, respectively

Mycobacterium tuberculosis Responds to Chloride and pH as Synergistic Cues to the Immune Status of its Host Cell

PubMed ID: 23592993This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Inflammatory bowel disease, such as Ulcerative colitis, is a risk factor for recurrent thromboembolic events: a case report

Ulcerative colitis (UC), a member of the family of inflammatory bowel disease (IBD), occurs worldwide. It has an incidence which in recent years has been rising in areas such as Southern Europe and Asia, while remaining relatively constant in Northern Europe and North America

Rethinking the politics of gender and agency: an encounter with the ‘otherness’ of medieval Japan

This article engages with recent debates within feminism itself to rethink women, gender, body, and agency as conceptual categories for reading medieval Japanese literary/Buddhist texts. It questions the unreflexive transposition of contemporary understandings of concepts to the past, on the grounds that this produces anachronistic readings of the worlds we seek to understand. It argues that in medieval Japanese texts gender did not function as a ‘social’ category posited against the ‘natural’ fact of sex, and that gender was a kind of script and that it was the specificity of the gendered performance, rather than the sexual attributes and reproductive functions of the body, that gave substance to the categories ‘male’ and ‘female.’ The article also offers a critique of contemporary uses of the term agency in analyses of women and Buddhism in medieval Japan, arguing that agency here is defined as something possessed by autonomous individuals with free will, whose natural inclination is to strive to resist against the oppressive conditions of their lives. This modern liberal conception of agency, which is secular in nature, grants agency to humans alone. This anthropocentric view of the world necessitates the evisceration of the agency of gods, buddhas, dreams and material objects, all of whom are central actors in the cosmological/social world of medieval Japan

Rapid detection of peptide markers for authentication purposes in raw and cooked meat using ambient liquid extraction surface analysis mass spectrometry

In this paper, our previously developed ambient LESA-MS methodology is implemented to analyze five types of thermally treated meat species, namely beef, pork, horse, chicken, and turkey meat, in order to select and identify heat-stable and species-specific peptide markers. In-solution tryptic digests of cooked meats were deposited onto a polymer surface, followed by LESA-MS analysis and evaluation using multivariate data analysis and tandem electrospray MS. The five types of cooked meat were clearly discriminated using principal component analysis and orthogonal partial least squares discriminant analysis. A number of 23 heat stable peptide markers unique to species and muscle protein were identified following data-dependent tandem LESA-MS analysis. Surface extraction and direct ambient MS analysis of mixtures of cooked meat species was performed for the first time and enabled detection of 10% (w/w) of pork, horse, and turkey meat, and 5% (w/w) of chicken meat in beef, using the developed LESA-MS/MS analysis. The study shows, for the first time, that ambient LESA-MS methodology displays specificity sufficient to be implemented effectively for the analysis of processed and complex peptide digests. The proposed approach is much faster and simpler than other measurement tools for meat speciation; it has potential for application in other areas of meat science or food production

The Hydroxamate Siderophore Rhequichelin Is Required for Virulence of the Pathogenic Actinomycete Rhodococcus equi

We previously showed that the facultative intracellular pathogen Rhodococcus equi produces a nondiffusible and catecholate-containing siderophore (rhequibactin) involved in iron acquisition during saprophytic growth. Here, we provide evidence that the rhbABCDE cluster directs the biosynthesis of a hydroxamate siderophore, rhequichelin, that plays a key role in virulence. The rhbC gene encodes a nonribosomal peptide synthetase that is predicted to produce a tetrapeptide consisting of N(5)-formyl-N(5)-hydroxyornithine, serine, N(5)-hydroxyornithine, and N(5)-acyl-N(5)-hydroxyornithine. The other rhb genes encode putative tailoring enzymes mediating modification of ornithine residues incorporated into the hydroxamate product of RhbC. Transcription of rhbC was upregulated during growth in iron-depleted medium, suggesting that it plays a role in iron acquisition. This was confirmed by deletion of rhbCD, rendering the resulting strain R. equi SID2 unable to grow in the presence of the iron chelator 2,2-dipyridyl. Supernatant of the wild-type strain rescued the phenotype of R. equi SID2. The importance of rhequichelin in virulence was highlighted by the rapid increase in transcription levels of rhbC following infection and the inability of R. equi SID2 to grow within macrophages. Unlike the wild-type strain, R. equi SID2 was unable to replicate in vivo and was rapidly cleared from the lungs of infected mice. Rhequichelin is thus a key virulence-associated factor, although nonpathogenic Rhodococcus species also appear to produce rhequichelin or a structurally closely related compound. Rhequichelin biosynthesis may therefore be considered an example of cooption of a core actinobacterial trait in the evolution of R. equi virulence

Different physiology of interferon-α/-γ in models of liver regeneration in the rat

Liver regeneration may take place after liver injury through replication of hepatocytes or hepatic progenitor cells called oval cells. Interferons (IFN) are natural cytokines with pleiotrophic effects including antiviral and antiproliferative actions. No data are yet available on the physiology and cellular source of natural IFNs during liver regeneration. To address this issue, we have analyzed the levels and biologic activities of IFN-α/IFN-γ in two models of partial hepatectomy. After 2/3rd partial hepatectomy (PH), hepatic levels of IFN-α and IFN-γ declined transiently in contrast to a transient increase of the IFN-γ serum level. After administration of 2-acetylaminofluorene and partial hepatectomy (AAF/PH model), however, both IFN-α and IFN-γ expression were up-regulated in regenerating livers. Again, the IFN-γ serum level was transiently increased. Whereas hepatic IFN-γ was up-regulated early (day 1–5), but not significantly, in the AAF/PH model, IFN-α was significantly up-regulated at later time points in parallel to the peak of oval cell proliferation (days 7–9). Biological activity of IFN-α was shown by activation of IFN-α-specific signal transduction and induction of IFN-α specific-gene expression. We found a significant infiltration of the liver with inflammatory monocyte-like mononuclear phagocytes (MNP) concomitant to the frequency of oval cells. We localized IFN-α production only in MNPs, but not in oval cells. These events were not observed in normal liver regeneration after standard PH. We conclude that IFN-γ functions as an acute-phase cytokine in both models of liver regeneration and may constitute a systemic component of liver regeneration. IFN-α was increased only in the AAF/PH model, and was associated with proliferation of oval cells. However, oval cells seem not to be the source of IFN-α. Instead, inflammatory MNP infiltrating AAF/PH-treated livers produce IFN-α. These inflammatory MNPs may be involved in the regulation of the oval cell compartment through local expression of cytokines, including IFN-α

Rhodococcus equi venous catheter infection: a case report and review of the literature

<p>Abstract</p> <p>Introduction</p> <p><it>Rhodococcus equi </it>is an animal pathogen that was initially isolated from horses and is being increasingly reported as a cause of infection in humans with impaired cellular immunity. However, this pathogen is underestimated as a challenging antagonist and is frequently considered to be a mere contaminant despite the potential for life-threatening infections. Most case reports have occurred in immunocompromised patients who have received organ transplants (for example kidney, heart, bone marrow) or those with human immunodeficiency virus infection. Infections often manifest as pulmonary involvement or soft tissue abscesses. Bacteremia related to <it>R. equi </it>infections of tunneled central venous catheters has rarely been described.</p> <p>Case presentation</p> <p>We report the case of a 63-year-old non-transplant recipient, non-HIV infected Caucasian woman with endometrial carcinoma who developed recurrent bloodstream infections and septic shock due to <it>R. equi </it>and ultimately required the removal of her port catheter, a subcutaneous implantable central venous catheter. We also review the medical literature related to human infections with <it>R. equi</it>.</p> <p>Conclusion</p> <p><it>R. equi </it>should be considered a serious pathogen, not a contaminant, particularly in an immunocompromised patient who presents with a central venous catheter-related bloodstream infection. Counseling patients with central venous catheters who participate in activities involving exposure to domesticated animals is recommended.</p

Microorganisms from aphid honeydew attract and enhance the efficacy of natural enemies

Aphids are one of the most serious pests of crops worldwide, causing major yield and economic losses. To control aphids, natural enemies could be an option but their efficacy is sometimes limited by their dispersal in natural environment. Here we report the first isolation of a bacterium from the pea aphid Acyrthosiphon pisum honeydew, Staphylococcus sciuri, which acts as a kairomone enhancing the efficiency of aphid natural enemies. Our findings represent the first case of a host-associated bacterium driving prey location and ovipositional preference for the natural enemy. We show that this bacterium has a key role in tritrophic interactions because it is the direct source of volatiles used to locate prey. Some specific semiochemicals produced by S. sciuri were also identified as significant attractants and ovipositional stimulants. The use of this host-associated bacterium could certainly provide a novel approach to control aphids in field and greenhouse systems

Aphid and Plant Volatiles Induce Oviposition in an Aphidophagous Hoverfly

Episyrphus balteatus DeGeer (Diptera, Syrphidae) is an abundant and efficient aphid-specific predator. We tested the electroantennographic (EAG) response of this syrphid fly to the common aphid alarm pheromone, (E)-β-farnesene (EβF), and to several plant volatiles, including terpenoids (mono- and sesquiterpenes) and green leaf volatiles (C6 and C9 alcohols and aldehydes). Monoterpenes evoked significant EAG responses, whereas sesquiterpenes were inactive, except for the aphid alarm pheromone (EβF). The most pronounced antennal responses were elicited by six and nine carbon green leaf alcohols and aldehydes [i.e., (Z)-3-hexenol, (E)-2-hexenol, (E)-2-hexenal, and hexanal]. To investigate the behavioral activity of some of these EAG-active compounds, E. balteatus females were exposed to R-(+)-limonene (monoterpene), (Z)-3-hexenol (green leaf alcohol), and EβF (sesquiterpene, common aphid alarm pheromone). A single E. balteatus gravid female was exposed for 10 min to an aphid-free Vicia faba plant that was co-located with a semiochemical dispenser. Without additional semiochemical, hoverfly females were not attracted to this plant, and no oviposition was observed. The monoterpene R-(+)-limonene did not affect the females’ foraging behavior, whereas (Z)-3-hexenol and EβF increased the time of flight and acceptance of the host plant. Moreover, these two chemicals induced oviposition on aphid-free plants, suggesting that selection of the oviposition site by predatory hoverflies relies on the perception of a volatile blend composed of prey pheromone and typical plant green leaf volatiles