35 research outputs found
A colorimetric strategy based on dynamic chemistry for direct detection of Trypanosomatid species
Leishmaniasis and Chagas disease are endemic in many countries, and re-emerging in the developed
countries. A rapid and accurate diagnosis is important for early treatment for reducing the duration
of infection as well as for preventing further potential health complications. In this work, we have
developed a novel colorimetric molecular assay that integrates nucleic acid analysis by dynamic
chemistry (ChemNAT) with reverse dot-blot hybridization in an array format for a rapid and easy
discrimination of Leishmania major and Trypanosoma cruzi. The assay consists of a singleplex PCR
step that amplifies a highly homologous DNA sequence which encodes for the RNA component of the
large ribosome subunit. The amplicons of the two different parasites differ between them by single
nucleotide variations, known as “Single Nucleotide Fingerprint” (SNF) markers. The SNF markers can
be easily identified by naked eye using a novel micro Spin-Tube device "Spin-Tube", as each of them
creates a specific spot pattern. Moreover, the direct use of ribosomal RNA without requiring the PCR
pre-amplification step is also feasible, further increasing the simplicity of the assay. The molecular
assay delivers sensitivity capable of identifying up to 8.7 copies per μL with single mismatch specificity.
The Spin-Tube thus represents an innovative solution providing benefits in terms of time, cost, and
simplicity, all of which are crucial for the diagnosis of infectious disease in developing countries.This research work has received funding from Junta de Andalucía, Consejería de Economía e Innovación (project
number 2012-BIO1778), the Spanish Ministerio de Economía y Competitividad (Grants CTQ2012-34778,
BIO2016-80519-R, FPI Grant BES-2013- 063020). This research was partially supported by the 7th European
Community Framework Program (FP7-PEOPLE-2012-CIG-Project Number 322276)
High Rate of Hypothyroidism in Multidrug-Resistant Tuberculosis Patients Co-Infected with HIV in Mumbai, India.
Adverse events (AEs) among HIV-infected patients with multidrug-resistant tuberculosis (MDR-TB) receiving anti-TB and antiretroviral treatments (ART) are under-researched and underreported. Hypothyroidism is a common AE associated with ethionamide, p-aminosalicylic acid (PAS), and stavudine. The aim of this study was to determine the frequency of and risk factors associated with hypothyroidism in HIV/MDR-TB co-infected patients
ATL9, a RING Zinc Finger Protein with E3 Ubiquitin Ligase Activity Implicated in Chitin- and NADPH Oxidase-Mediated Defense Responses
Pathogen associated molecular patterns (PAMPs) are signals detected by plants that activate basal defenses. One of these PAMPs is chitin, a carbohydrate present in the cell walls of fungi and in insect exoskeletons. Previous work has shown that chitin treatment of Arabidopsis thaliana induced defense-related genes in the absence of a pathogen and that the response was independent of the salicylic acid (SA), jasmonic acid (JA) and ethylene (ET) signaling pathways. One of these genes is ATL9 ( = ATL2G), which encodes a RING zinc-finger like protein. In the current work we demonstrate that ATL9 has E3 ubiquitin ligase activity and is localized to the endoplasmic reticulum. The expression pattern of ATL9 is positively correlated with basal defense responses against Golovinomyces cichoracearum, a biotrophic fungal pathogen. The basal levels of expression and the induction of ATL9 by chitin, in wild type plants, depends on the activity of NADPH oxidases suggesting that chitin-mediated defense response is NADPH oxidase dependent. Although ATL9 expression is not induced by treatment with known defense hormones (SA, JA or ET), full expression in response to chitin is compromised slightly in mutants where ET- or SA-dependent signaling is suppressed. Microarray analysis of the atl9 mutant revealed candidate genes that appear to act downstream of ATL9 in chitin-mediated defenses. These results hint at the complexity of chitin-mediated signaling and the potential interplay between elicitor-mediated signaling, signaling via known defense pathways and the oxidative burst
Complete Genome Sequence of the N2-Fixing Broad Host Range Endophyte Klebsiella pneumoniae 342 and Virulence Predictions Verified in Mice
We report here the sequencing and analysis of the genome of the nitrogen-fixing endophyte, Klebsiella pneumoniae 342. Although K. pneumoniae 342 is a member of the enteric bacteria, it serves as a model for studies of endophytic, plant-bacterial associations due to its efficient colonization of plant tissues (including maize and wheat, two of the most important crops in the world), while maintaining a mutualistic relationship that encompasses supplying organic nitrogen to the host plant. Genomic analysis examined K. pneumoniae 342 for the presence of previously identified genes from other bacteria involved in colonization of, or growth in, plants. From this set, approximately one-third were identified in K. pneumoniae 342, suggesting additional factors most likely contribute to its endophytic lifestyle. Comparative genome analyses were used to provide new insights into this question. Results included the identification of metabolic pathways and other features devoted to processing plant-derived cellulosic and aromatic compounds, and a robust complement of transport genes (15.4%), one of the highest percentages in bacterial genomes sequenced. Although virulence and antibiotic resistance genes were predicted, experiments conducted using mouse models showed pathogenicity to be attenuated in this strain. Comparative genomic analyses with the presumed human pathogen K. pneumoniae MGH78578 revealed that MGH78578 apparently cannot fix nitrogen, and the distribution of genes essential to surface attachment, secretion, transport, and regulation and signaling varied between each genome, which may indicate critical divergences between the strains that influence their preferred host ranges and lifestyles (endophytic plant associations for K. pneumoniae 342 and presumably human pathogenesis for MGH78578). Little genome information is available concerning endophytic bacteria. The K. pneumoniae 342 genome will drive new research into this less-understood, but important category of bacterial-plant host relationships, which could ultimately enhance growth and nutrition of important agricultural crops and development of plant-derived products and biofuels
Identifying variation in resistance to the take-all fungus, Gaeumannomyces graminis var. tritici, between different ancestral and modern wheat species
Background: Ancestral wheat relatives are important sources of genetic diversity for the introduction of novel traits
for the improvement of modern bread wheat. In this study the aim was to assess the susceptibility of 34 accessions
of the diploid wheat Triticum monococcum (A genome) to Gaeumannomyces graminis var. tritici (Ggt), the causal
agent of take-all disease. The second aim was to explore the susceptibility of tetraploid wheat (T. durum) and the B
genome progenitor species Aegilops speltoides to Ggt.
Results: Field trials, conducted over 5 years, identified seven T. monococcum accessions with a good level of
resistance to take-all when exposed to natural inoculum under UK field conditions. All other accessions were highly
susceptible or did not exhibit a consistent phenotype across years. DArT marker genotyping revealed that whole
genome diversity was not closely related to resistance to take-all within T. monococcum, suggesting that multiple
genetic sources of resistance may exist within the species. In contrast the tetraploid wheat cultivars and Ae. speltoides
were all highly susceptible to the disease, including those with known elevated levels of benzoxazinoids.
Conclusions: The diploid wheat species T. monococcum may provide a genetic source of resistance to take-all disease
that could be utilised to improve the performance of T. aestivum in high disease risk situations. This represents an
extremely valuable resource to achieve economic and sustainable genetic control of this root disease
Multi-messenger observations of a binary neutron star merger
On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta