1,637 research outputs found
Finished Genome Sequences of Xanthomonas fragariae, the Cause of Bacterial Angular Leaf Spot of Strawberry.
Xanthomonas fragariae is a foliar pathogen of strawberry that is of significant concern to nursery production of strawberry transplants and field production of strawberry fruit. Long-read sequencing was employed to generate finished genomes for two isolates (each with one chromosome and two plasmids) from symptomatic plants in northern California
Inhibition of Xanthomonas fragariae, Causative Agent of Angular Leaf Spot of Strawberry, through Iron Deprivation.
In commercial production settings, few options exist to prevent or treat angular leaf spot (ALS) of strawberry, a disease of economic importance and caused by the bacterial pathogen Xanthomonas fragariae. In the process of isolating and identifying X. fragariae bacteria from symptomatic plants, we observed growth inhibition of X. fragariae by bacterial isolates from the same leaf macerates. Identified as species of Pseudomonas and Rhizobium, these isolates were confirmed to suppress growth of X. fragariae in agar overlay plates and in microtiter plate cultures, as did our reference strain Pseudomonas putida KT2440. Screening of a transposon mutant library of KT2440 revealed that disruption of the biosynthetic pathway for the siderophore pyoverdine resulted in complete loss of X. fragariae antagonism, suggesting iron competition as a mode of action. Antagonism could be replicated on plate and in culture by addition of purified pyoverdine or by addition of the chelating agents tannic acid and dipyridyl, while supplementing the medium with iron negated the inhibitory effects of pyoverdine, tannic acid and dipyridyl. When co-inoculated with tannic acid onto strawberry plants, X. fragariae's ability to cause foliar symptoms was greatly reduced, suggesting a possible opportunity for iron-based management of ALS. We discuss our findings in the context of 'nutritional immunity,' the idea that plant hosts restrict pathogen access to iron, either directly, or indirectly through their associated microbiota
Cross Cultural Workers for women and families from migrant and refugee backgrounds: a mixed-methods study of service providers perceptions
Background
Women from migrant and refugee backgrounds who live in high-income countries are at increased risk of adverse perinatal outcomes, including mental health issues, preterm birth and maternal and infant mortality. There is a need to implement and evaluate models of care to meet their specific needs in order to improve health outcomes, their experiences of care, and overcome barriers to access. In Sydney, Australia, a unique model of care was implemented to support women and families from migrant and refugee backgrounds to access health and community-based services through the continuum of pregnancy to the early parenting period. This model of care is known as the Cross Cultural Workers (CCWs) in Maternity and Child and Family Health Service (the CCW Service). The aim of this study was to explore the perceptions of service providers regarding the CCW Service and identify recommendations for improvement.
Methods
A mixed-methods study was conducted consisting of surveys and face to face semi-structured interviews. Service providers were recruited from hospital-based maternity and community-based services. Survey data were analysed descriptively. Interviews were analysed using qualitative content analysis.
Results
Sixty-nine service providers completed surveys and 19 were interviewed. The CCW Service was highly regarded by service providers who perceived it to be critical in improving care for women from migrant and refugee backgrounds. The overarching theme from the interviews was the ability of the CCW Service to act as a ‘bridge to health’ through the provision of culturally responsive care. There were three main categories; supporting access to health and community-based services, improving the healthcare experience, and organisational factors, including part-time hours, capacity, heavy workloads and confusion/lack of clarity regarding the CCW role, which affected CCWs’ capacity to optimally support service providers in providing culturally responsive care. These limitations meant CCWs were not able to meet demand, and fully operationalise the model.
Conclusion
Service providers perceived the CCW model to be a culturally responsive model of care tailored to the needs of women and families from migrant and refugee backgrounds, that reduces barriers to access, and has the potential to improve perinatal outcomes, and women's experience and satisfaction with care
D-420720, A Novel Orally Active Sulfonamide Compound Dipeptidyl Peptidase IV Inhibitor: Structure and Activity Relationship of Arylsuffonamide to Dipeptidyl Peptidase IV Inhibition
[[abstract]]Diabetes mellitus is a chronic disease characteristic of poor glucose homeostasis that requires constant monitoring and adjustment of blood glucose levels by exogenous intervention. Glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP) are two incretin peptide hormones secreted from the intestine to synergize insulin's function at lowering blood glucose. The effects of GLP-1 or GIP administration are short-lived because they are rapidly inactivated by circulating dipeptidyl peptidase IV (DPP-IV). Therefore, DPP-IV inhibitors have been suggested to be a new class of molecule for treating hyperglycemic conditions in diabetic patients. The recent approval of Merck's Sitagliptin (a DPP-IV-specific inhibitor) indicates that DPP-IV inhibition is a good target for new therapeutic agent development. The present study was conducted to evaluate the efficacies of a series of dipeptidyl derivatives with a sulfonamide moiety as DPP-IV inhibitors. Among these compounds, D-420720 was a potent inhibitor (K-i = 39 nM), with a selectivity of 9160-fold over the DPP-II isozyme and elicits a hypoglycemic effect on oral glucose tolerance test with normal male ICR mice. Drug Dev Res 69:514-519,2008 (C) 2008 Wiley-Liss, Inc
A novel hydroxyfuroic acid compound as an insulin receptor activator structure and activity relationship of a prenylindole moiety to insulin receptor activation
[[abstract]]Background: Diabetes Mellitus is a chronic disease and many patients of which require frequent subcutaneous insulin injection to maintain proper blood glucose levels. Due to the inconvenience of insulin administration, an orally active insulin replacement has long been a prime target for many pharmaceutical companies. Demethylasterriquinone (DMAQ) B1, extracted from tropical fungus, Pseudomassaria sp., has been reported to be an orally effective agent at lowering circulating glucose levels in diabetic (db/db) mice; however, the cytotoxicity associated with the quinone moiety has not been addressed thus far.
Methods: A series of hydroxyfuroic acid compounds were synthesized and tested for their efficacies at activating human insulin receptor. Cytotoxicity to Chinese hamster ovary cells, selectivities over insulin-like growth factor-1 (IGF-1), epidermal growth factor (EGF), and fibroblast growth factor (FGF) receptors were examined in this study.
Result and Conclusion: This study reports a new non-quinone DMAQ B1 derivative, a hydroxyfuroic acid compound (D-410639), which is 128 fold less cytotoxic as DMAQ B1 and as potent as compound 2, a DMAQ B1 synthetic derivative from Merck, at activating human insulin receptor. D-410639 has little activation potential on IGF-1 receptor but is a moderate inhibitor to EGF receptor. Structure and activity relationship of the prenylindole moiety to insulin receptor activation is discussed
Multiplexed SNP Typing of Ancient DNA Clarifies the Origin of Andaman mtDNA Haplogroups amongst South Asian Tribal Populations
The issue of errors in genetic data sets is of growing concern, particularly in population genetics where whole genome mtDNA sequence data is coming under increased scrutiny. Multiplexed PCR reactions, combined with SNP typing, are currently under-exploited in this context, but have the potential to genotype whole populations rapidly and accurately, significantly reducing the amount of errors appearing in published data sets. To show the sensitivity of this technique for screening mtDNA genomic sequence data, 20 historic samples of the enigmatic Andaman Islanders and 12 modern samples from three Indian tribal populations (Chenchu, Lambadi and Lodha) were genotyped for 20 coding region sites after provisional haplogroup assignment with control region sequences. The genotype data from the historic samples significantly revise the topologies for the Andaman M31 and M32 mtDNA lineages by rectifying conflicts in published data sets. The new Indian data extend the distribution of the M31a lineage to South Asia, challenging previous interpretations of mtDNA phylogeography. This genetic connection between the ancestors of the Andamanese and South Asian tribal groups ∼30 kya has important implications for the debate concerning migration routes and settlement patterns of humans leaving Africa during the late Pleistocene, and indicates the need for more detailed genotyping strategies. The methodology serves as a low-cost, high-throughput model for the production and authentication of data from modern or ancient DNA, and demonstrates the value of museum collections as important records of human genetic diversity
Inflation on the Brane with Vanishing Gravity
Many existing models of brane inflation suffer from a steep irreducible
gravitational potential between the branes that causes inflation to end too
early. Inspired by the fact that point masses in 2+1 D exert no gravitational
force, we propose a novel unwarped and non-supersymmetric setup for inflation,
consisting of 3-branes in two extra dimensions compactified on a sphere. The
size of the sphere is stabilized by a combination of a bulk cosmological
constant and a magnetic flux. Computing the 4D effective potential between
probe branes in this background, we find a non-zero contribution only from
exchange of level-1 KK modes of the graviton and radion. Identifying antipodal
points on the 2-sphere projects out these modes, eliminating entirely the
troublesome gravitational contribution to the inflationary potential.Comment: 19 pages, 11 figures, JHEP forma
Transit Photometry as an Exoplanet Discovery Method
Photometry with the transit method has arguably been the most successful
exoplanet discovery method to date. A short overview about the rise of that
method to its present status is given. The method's strength is the rich set of
parameters that can be obtained from transiting planets, in particular in
combination with radial velocity observations; the basic principles of these
parameters are given. The method has however also drawbacks, which are the low
probability that transits appear in randomly oriented planet systems, and the
presence of astrophysical phenomena that may mimic transits and give rise to
false detection positives. In the second part we outline the main factors that
determine the design of transit surveys, such as the size of the survey sample,
the temporal coverage, the detection precision, the sample brightness and the
methods to extract transit events from observed light curves. Lastly, an
overview over past, current and future transit surveys is given. For these
surveys we indicate their basic instrument configuration and their planet
catch, including the ranges of planet sizes and stellar magnitudes that were
encountered. Current and future transit detection experiments concentrate
primarily on bright or special targets, and we expect that the transit method
remains a principal driver of exoplanet science, through new discoveries to be
made and through the development of new generations of instruments.Comment: Review chapte
A Method for Serial Tissue Processing and Parallel Analysis of Aberrant Crypt Morphology, Mucin Depletion, and Beta-Catenin Staining in an Experimental Model of Colon Carcinogenesis
The use of architectural and morphological characteristics of cells for establishing prognostic indicators by which individual pathologies are assigned grade and stage is a well-accepted practice. Advances in automated micro- and macroscopic image acquisition and digital image analysis have created new opportunities in the field of prognostic assessment; but, one area in experimental pathology, animal models for colon cancer, has not taken advantage of these opportunities. This situation is primarily due to the methods available to evaluate the colon of the rodent for the presence of premalignant and malignant pathologies. We report a new method for the excision and processing of the entire colon of the rat and illustrate how this procedure permitted the quantitative assessment of aberrant crypt foci (ACF), a premalignant colon pathology, for characteristics consistent with progression to malignancy. ACF were detected by methylene blue staining and subjected to quantitative morphometric analysis. Colons were then restained with high iron diamine–alcian blue for assessment of mucin depletion using an image overlay to associate morphometric data with mucin depletion. The subsequent evaluation of ACF for beta-catenin staining is also demonstrated. The methods described are particularly relevant to the screening of compounds for cancer chemopreventive activity
Mood instability, mental illness and suicidal ideas : results from a household survey
Purpose:
There is weak and inconsistent evidence that mood instability (MI) is associated with depression, post traumatic stress disorder (PTSD) and suicidality although the basis of this is unclear. Our objectives were first to test whether there is an association between depression and PTSD, and MI and secondly whether MI exerts an independent effect on suicidal thinking over and above that explained by common mental disorders.
Methods:
We used data from the Adult Psychiatric Morbidity Survey 2007 (N = 7,131). Chi-square tests were used to examine associations between depression and PTSD, and MI, followed by regression modelling to examine associations between MI and depression, and with PTSD. Multiple logistic regression analyses were used to assess the independent effect of MI on suicidal thinking, after adjustment for demographic factors and the effects of common mental disorder diagnoses.
Results:
There are high rates of MI in depression and PTSD and the presence of MI increases the odds of depression by 10.66 [95 % confidence interval (CI) 7.51–15.13] and PTSD by 8.69 (95 % CI 5.90–12.79), respectively, after adjusting for other factors. Mood instability independently explained suicidal thinking, multiplying the odds by nearly five (odds ratio 4.82; 95 % CI 3.39–6.85), and was individually by some way the most important single factor in explaining suicidal thoughts.
Conclusions:
MI is strongly associated with depression and PTSD. In people with common mental disorders MI is clinically significant as it acts as an additional factor exacerbating the risk of suicidal thinking. It is important to enquire about MI as part of clinical assessment and treatment studies are required
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