23 research outputs found

    A Transcriptional “Scream” Early Response of E. coli Prey to Predatory Invasion by Bdellovibrio

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    We have transcriptionally profiled the genes differentially expressed in E. coli prey cells when predatorily attacked by Bdellovibrio bacteriovorus just prior to prey cell killing. This is a brief, approximately 20–25 min period when the prey cell is still alive but contains a Bdellovibrio cell in its periplasm or attached to and penetrating its outer membrane. Total RNA was harvested and labelled 15 min after initiating a semi-synchronous infection with an excess of Bdellovibrio preying upon E. coli and hybridised to a macroarray spotted with all predicted ORFs of E. coli. SAM analysis and t-tests were performed on the resulting data and 126 E. coli genes were found to be significantly differentially regulated by the prey upon attack by Bdellovibrio. The results were confirmed by QRT-PCR. Amongst the prey genes upregulated were a variety of general stress response genes, potentially “selfish” genes within or near prophages and transposable elements, and genes responding to damage in the periplasm and osmotic stress. Essentially, the presence of the invading Bdellovibrio and the resulting damage to the prey cell elicited a small “transcriptional scream”, but seemingly no specific defensive mechanism with which to counter the Bdellovibrio attack. This supports other studies which do not find Bdellovibrio resistance responses in prey, and bodes well for its use as a “living antibiotic”

    Obesity at age 20 and the risk of miscarriages, irregular periods and reported problems of becoming pregnant: the Adventist Health Study-2

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    In a group of 46,000 North-American Adventist women aged 40 and above, we investigated the relationships between body mass index (BMI, kg/m(2)) at age 20 and the proportion of women who reported at least one miscarriage, periods with irregular menstruation or failing to become pregnant even if trying for more than one straight year. Approximately 31, 14 and 17 %, respectively, reported the three different problems related to reproduction. Positive age- and marital status adjusted relationships were found between BMI at age 20 and periods with irregular menstruation or failing to become pregnant even if trying for more than 1 year, but not with the risk of miscarriages. Women with BMI ≥ 32.5 kg/m(2) when aged 20 had approximately 2.0 (95 % CI: 1.6, 2.4) and 1.5 (95 % CI: 1.3, 1.9) higher odds for irregular periods or failing to get pregnant, respectively, than women with BMI in the 20–24.9 kg/m(2) bracket. These relationships were consistently found in a number of strata of the population, including the large proportion of the women who never had smoked or never used alcohol. Underweight (BMI < 18.5 kg/m(2)) when aged 20 marginally (approximately 15 %) increased the risk of failing to get pregnant within a year. Thus, obesity at age 20 increases the risk of reporting some specific reproductive problems, but not the risk of miscarriages. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s10654-012-9749-8) contains supplementary material, which is available to authorized users

    A high-throughput method for the quantitative analysis of auxins

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    Auxin measurements in plants are critical to understanding both auxin signaling and metabolic homeostasis. The most abundant natural auxin is indole-3-acetic acid (IAA). This protocol is for the precise, high-throughput determination of free IAA in plant tissue by isotope dilution analysis using gas chromatography-mass spectrometry (GC-MS). The steps described are as follows: harvesting of plant material; amino and polymethylmethacrylate solid-phase purification followed by derivatization with diazomethane (either manual or robotic); GC-MS analysis; and data analysis. [¹³C₆]IAA is the standard used. The amount of tissue required is relatively small (25 mg of fresh weight) and one can process more than 500 samples per week using an automated system. To extract eight samples, this procedure takes ∼3 h, whether performed manually or robotically. For processing more than eight samples, robotic extraction becomes substantially more time efficient, saving at least 0.5 h per additional batch of eight samples

    Assessment and management of neurogenic claudication associated with lumbar spinal stenosis in a UK primary care musculoskeletal service: a survey of current practice among physiotherapists

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    BACKGROUND Neurogenic claudication (NC) is the clinical syndrome commonly associated with lumbar spinal stenosis (LSS). Non-surgical management is recommended as initial treatment, but little is known about current practice in relation to the assessment and management of these patients in the non-surgical setting. METHODS We conducted a questionnaire survey of physiotherapists in a large UK primary care musculoskeletal service which provides a city-wide multidisciplinary assessment and treatment facility for patients with spinal and other musculoskeletal problems. Data on therapists' recognition and management of patients with NC and LSS were collected. RESULTS Fifty out of 54 therapists completed questionnaires, and all but one of these identified a clearly recognised posture-related clinical syndrome of NC. Almost all respondents (48: 96%) reported the routine use of physiotherapy treatments. In particular, advice and education (49: 98%) along with an exercise programme (47: 94%) incorporating flexion-based exercises (41: 82%) and trunk muscle stabilising exercises (35: 70%) were favoured. CONCLUSION Musculoskeletal physiotherapy clinicians in this survey recognised a clear clinical syndrome of NC, based on the findings of posture-dependent symptoms. Most therapists reported the routine use of flexion-based exercise, reflecting recommendations in the literature which are based on theoretical benefits, but for which trial evidence is lacking. There is a need for research evidence to guide the choice of physiotherapy treatments
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