3,958 research outputs found

    A commercial arbuscular mycorrhizal inoculum increases root colonization across wheat cultivars but does not increase assimilation of mycorrhizaā€acquired nutrients

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    Production and heavy application of chemicalā€based fertilizers to maintain crop yields is unsustainable due to pollution from runā€off, high CO2 emissions, and diminishing yield returns. Access to fertilizers will be limited in the future due to rising energy costs and dwindling rock phosphate resources. A growing number of companies produce and sell arbuscular mycorrhizal fungal (AMF) inoculants, intended to help reduce fertilizer usage by facilitating crop nutrient uptake through arbuscular mycorrhizas. However, their success has been variable. Here, we present information about the efficacy of a commercially available AMF inoculant in increasing AMF root colonization and fungal contribution to plant nutrient uptake, which are critical considerations within the growing AMF inoculant industry. Summary Arable agriculture needs sustainable solutions to reduce reliance on large inputs of nutrient fertilizers while continuing to improve crop yields. By harnessing arbuscular mycorrhizal symbiosis, there is potential to improve crop nutrient assimilation and growth without additional inputs, although the efficacy of commercially available mycorrhizal inocula in agricultural systems remains controversial. Using stable and radioisotope tracing, carbonā€forā€nutrient exchange between arbuscular mycorrhizal fungi and three modern cultivars of wheat was quantified in a nonā€sterile, agricultural soil, with or without the addition of a commercial mycorrhizal inoculant. While there was no effect of inoculum addition on aboveā€ground plant biomass, there was increased root colonization by arbuscular mycorrhizal fungi and changes in community structure. Inoculation increased phosphorus uptake across all wheat cultivars by up to 30%, although this increase was not directly attributable to mycorrhizal fungi. Carbonā€forā€nutrient exchange between symbionts varied substantially between the wheat cultivars. Plant tissue phosphorus increased in inoculated plants potentially because of changes induced by inoculation in microbial community composition and/or nutrient cycling within the rhizosphere. Our data contribute to the growing consensus that mycorrhizal inoculants could play a role in sustainable food production systems of the future

    An Extended Photoperiod Increases Milk Yield and Decreases Ovulatory Activity in Dairy Goats

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    Short day length is associated with reduced milk production in dairy ruminants. Dairy ruminants have been kept in lit sheds during winter to extend the day length and stimulate milk production. However, there studies are few on the effect of an extended photoperiod on the ensuing reproductive performance of dairy goats. The aim of this study was to examine the effect of long day photoperiod (LDPP) and exposure to bucks on milk production and plasma progesterone and prolactin in dairy goats. The study was conducted in 122 non-pregnant lactating dairy goats over 18 weeks from April to August (late autumn and winter in the Southern Hemisphere). The goats were kept in open sided sheds in which the control treatment received ambient lighting while the LDPP treatment received 16 h of light, including artificial lighting. In June, July and August synchronised does were randomly assigned each month to the presence or absence of a buck and ovulatory activity determined from plasma progesterone. Plasma progesterone concentrations were reduced (0.73 vs. 0.46 pmol, p < 0.001) while prolactin concentrations were increased (0.095 vs. 1.33 ng/mL, p < 0.001) in LDPP goats. The former response was most marked in late winter (0.58 vs. 0.004 pmol, p < 0.001) indicating a lack of functional corpora lutea. While there was no overall effect of buck exposure on plasma progesterone concentrations there was a three-way interaction such that plasma progesterone concentrations were increased (p < 0.05) by exposure to bucks in LDPP goats in August (late winter) but not at other times. Milk production was increased in LDPP goats over the latter stages of the study (1. 55 vs. 1.82 L/d, p < 0.05). Also, persistency of lactation was greater in LDPP goats with fewer goats drying off (13 vs. 0%, p < 0.05). These findings suggest that LDPP can increase milk production and persistence while decreasing ovulatory activity in dairy goats

    A bi-directional relationship between obesity and health-related quality of life : evidence from the longitudinal AusDiab study

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    Objective: To assess the prospective relationship between obesity and health-related quality of life, including a novel assessment of the impact of health-related quality of life on weight gain.Design and setting: Longitudinal, national, population-based Australian Diabetes, Obesity and Lifestyle (AusDiab) study, with surveys conducted in 1999/2000 and 2004/2005.Participants: A total of 5985 men and women aged 25 years at study entry.Main outcome measure(s): At both time points, height, weight and waist circumference were measured and self-report data on health-related quality of life from the SF-36 questionnaire were obtained. Cross-sectional and bi-directional, prospective associations between obesity categories and health-related quality of life were assessed.Results: Higher body mass index (BMI) at baseline was associated with deterioration in health-related quality of life over 5 years for seven of the eight health-related quality of life domains in women (all P0.01, with the exception of mental health, P&gt;0.05), and six out of eight in men (all P&lt;0.05, with the exception of role-emotional, P=0.055, and mental health, P&gt;0.05). Each of the quality-of-life domains related to mental health as well as the mental component summary were inversely associated with BMI change (all P&lt;0.0001 for women and P0.01 for men), with the exception of vitality, which was significant in women only (P=0.008). For the physical domains, change in BMI was inversely associated with baseline general health in women only (P=0.023).Conclusions: Obesity was associated with a deterioration in health-related quality of life (including both physical and mental health domains) in this cohort of Australian adults followed over 5 years. Health-related quality of life was also a predictor of weight gain over 5 years, indicating a bi-directional association between obesity and health-related quality of life. The identification of those with poor health-related quality of life may be important in assessing the risk of future weight gain, and a focus on health-related quality of life may be beneficial in weight management strategies.<br /

    Adapting tissue-engineered in vitro CNS models for high-throughput study of neurodegeneration

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    Neurodegenerative conditions remain difficult to treat, with the continuing failure to see therapeutic research successfully advance to clinical trials. One of the obstacles that must be overcome is to develop enhanced models of disease. Tissue engineering techniques enable us to create organised artificial central nervous system tissue that has the potential to improve the drug development process. This study presents a replicable model of neurodegenerative pathology through the use of engineered neural tissue co-cultures that can incorporate cells from various sources and allow degeneration and protection of neurons to be observed easily and measured, following exposure to neurotoxic compounds - okadaic acid and 1-methyl-4-phenylpyridinium. Furthermore, the technology has been miniaturised through development of a mould with 6 mm length that recreates the advantageous features of engineered neural tissue co-cultures at a scale suitable for commercial research and development. Integration of human-derived induced pluripotent stem cells aids more accurate modelling of human diseases, creating new possibilities for engineered neural tissue co-cultures and their use in drug screening

    Automatic correction of hand pointing in stereoscopic depth

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    In order to examine whether stereoscopic depth information could drive fast automatic correction of hand pointing, an experiment was designed in a 3D visual environment in which participants were asked to point to a target at different stereoscopic depths as quickly and accurately as possible within a limited time window (ā‰¤300ā€…ms). The experiment consisted of two tasks: "depthGO" in which participants were asked to point to the new target position if the target jumped, and "depthSTOP" in which participants were instructed to abort their ongoing movements after the target jumped. The depth jump was designed to occur in 20% of the trials in both tasks. Results showed that fast automatic correction of hand movements could be driven by stereoscopic depth to occur in as early as 190ā€…ms.This work was supported by the Grants from the National Natural Science Foundation of China (60970062 and 61173116) and the Doctoral Fund of Ministry of Education of China (20110072110014)

    Patients with aortic stenosis exhibit early improved endothelial function following transcatheter aortic valve replacement: The eFAST study

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    BACKGROUND: Patients with severe aortic stenosis (AS) exhibit systemic endothelial dysfunction, which can be associated with myocardial ischaemia in absence of obstructive coronary disease. Transcatheter aortic valve replacement (TAVR) is used to treat severe AS in patients with high or prohibitive surgical risk. However, it remains unknown whether endothelial function recovers post-TAVR. We therefore sought to assess the early and late changes in flow-mediated dilation (FMD), a measure of endothelial function, following TAVR. METHODS: Patients undergoing TAVR for severe AS had ultrasound assessment of brachial endothelial-independent and -dependent FMD. Measurements were performed pre-TAVR, at early follow-up (<48 h post-TAVR) and late follow-up (4-6 weeks post-TAVR). RESULTS: 27 patients (mean age 82.0 Ā± 7.0; 33.3% female) were recruited; 37.0% had diabetes mellitus and 59.3% had hypertension. Brachial artery FMD increased from 4.2 Ā± 1.6% (pre-TAVR) to 9.7 Ā± 3.5% at early follow-up (p < 0.0001). At late follow-up, improvement compared with early follow-up was sustained (8.7 Ā± 1.9%, p = 0.27). Resting brachial arterial flow velocities decreased significantly at late follow-up (11.24 Ā± 5.16 vs. 7.73 Ā± 2.79 cm/s, p = 0.003). Concordantly, at late follow-up, there was decrease in resting wall shear stress (WSS; 14.8 Ā± 7.8 vs. 10.6 Ā± 4.8dyne/cm2, p = 0.01), peak WSS (73.1 Ā± 34.1 vs. 58.8 Ā± 27.8dyne/cm2, p = 0.03) and cumulative WSS (3543 Ā± 1852 vs. 2504 Ā± 1089dyneĀ·s/cm2, p = 0.002). Additionally, a favourable inverse correlation between cumulative WSS and FMD was restored at late follow-up (r = -0.21 vs. r = 0.49). CONCLUSION: Endothelial function in patients with AS improves early post-TAVR and this improvement is sustained. This likely occurs as a result of improved arterial haemodynamics, leading to lower localised WSS and release of vasoactive mediators that may also alleviate myocardial ischaemia

    Dietary antioxidant intake and the risk of developing Barrettā€™s oesophagus and oesophageal adenocarcinoma

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    Background: We investigated in a cohort study, for the first time using 7-day food diaries (7-DFDs), for age-dependent inverse associations with antioxidants, which have anti-carcinogenic properties, and development of Barrettā€™s oesophagus (BO) and oesophageal adenocarcinoma (OAC). Methods: A total of 24,068 well individuals completed 7-DFDs and donated blood. Vitamins C and E, carotenes, zinc and selenium intakes, and plasma vitamin C were measured. Participants were monitored for 15 years for BO and OAC. Hazard ratios (HRs) were estimated for: quintiles of intake and in participants younger and >=65 years at recruitment, the midpoint of BO peak prevalence. Results: A total of 197 participants developed BO and 74 OAC. There were no significant associations between antioxidants and BO or OAC in the whole cohort or if >65 years at recruitment. In participants <65 years, for BO, there was an inverse trend across plasma vitamin C quintiles (trend HRā€‰=ā€‰0.82; 95% CIā€‰=ā€‰0.71ā€“0.96, Pā€‰=ā€‰0.01), OAC for plasma vitamin C (trend HRā€‰=ā€‰0.58; 95% CIā€‰=ā€‰0.37ā€“0.92, Pā€‰=ā€‰0.02) and for dietary vitamins C and E (trend HRā€‰=ā€‰0.71 95% CIā€‰=ā€‰0.51ā€“0.99, Pā€‰=ā€‰0.04 and trend HRā€‰=ā€‰0.70; 95% CIā€‰=ā€‰0.51ā€“0.96; Pā€‰=ā€‰0.03). Conclusions: Data supports a role for dietary antioxidants prevent BO and OAC, perhaps at the earlier stages of carcinogenesis

    Changing Pattern of Esophageal Cancer Incidence in New Mexico: A 30-Year Evaluation

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    The incidence of esophageal adenocarcinoma has increased over the last 30Ā years, especially in non-Hispanic whites (nHw). Recent work indicates an increase in Hispanic Americans (HA). It is important to understand the effect of ethnicity on cancer occurrence over a prolonged interval. We searched the New Mexico Tumor Registry for all cases of esophageal cancer from 1 January 1973 to 31 December 2002. Inclusion criteria were histologic diagnosis of adenocarcinoma or squamous cell carcinoma, ethnicity and gender. Incidence rates for both were compared among ethnic groups in 5-year intervals. Nine hundred eighty-eight patients met the criteria. Esophageal adenocarcinoma incidence rates/100,000 population increased significantly over 30Ā years; 1973ā€“1977, 0.4 cases; 1978ā€“1982, 0.4 cases; 1983ā€“1987, 0.6 cases; 1988ā€“1992, 1.2 cases, 1993ā€“1997, 1.6 cases and 1998ā€“2002, 2.2 cases; PĀ &lt;Ā 0.001. Squamous cell carcinoma incidence rates remained unchanged during the interval. In nHw and HA, adenocarcinoma incidence rates increased significantly during the study period. In all minority groups, squamous cell carcinoma remained the major type. Esophageal adenocarcinoma incidence among nHw and HA increased from 1973 to 2002 in New Mexico. Squamous cell carcinoma remains predominant in minorities. Ethnicity may influence the histology or indicate an increased risk for certain types of esophageal cancer

    Feasibility and Validity of Computed Tomography-Derived Fractional Flow Reserve in Patients With Severe Aortic Stenosis: The CAST-FFR Study

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    BACKGROUND: Coronary artery disease is common in patients with severe aortic stenosis. Computed tomography-derived fractional flow reserve (CT-FFR) is a clinically used modality for assessing coronary artery disease, however, its use has not been validated in patients with severe aortic stenosis. This study assesses the safety, feasibility, and validity of CT-FFR in patients with severe aortic stenosis. METHODS: Prospectively recruited patients underwent standard-protocol invasive FFR and coronary CT angiography (CTA). CTA images were analyzed by central core laboratory (HeartFlow, Inc) for independent evaluation of CT-FFR. CT-FFR data were compared with FFR (ischemia defined as FFR ā‰¤0.80). RESULTS: Forty-two patients (68 vessels) underwent FFR and CTA; 39 patients (92.3%) and 60 vessels (88.2%) had interpretable CTA enabling CT-FFR computation. Mean age was 76.2Ā±6.7 years (71.8% male). No patients incurred complications relating to premedication, CTA, or FFR protocol. Mean FFR and CT-FFR were 0.83Ā±0.10 and 0.77Ā±0.14, respectively. CT calcium score was 1373.3Ā±1392.9 Agatston units. On per vessel analysis, there was positive correlation between FFR and CT-FFR (Pearson correlation coefficient, R=0.64, P<0.0001). Sensitivity, specificity, positive predictive value, and negative predictive values were 73.9%, 78.4%, 68.0%, and 82.9%, respectively, with 76.7% diagnostic accuracy. The area under the receiver-operating characteristic curve for CT-FFR was 0.83 (0.72-0.93, P<0.0001), which was higher than that of CTA and quantitative coronary angiography (P=0.01 and P<0.001, respectively). Bland-Altman plot showed mean bias between FFR and CT-FFR as 0.059Ā±0.110. On per patient analysis, the sensitivity, specificity, positive predictive, and negative predictive values were 76.5%, 77.3%, 72.2%, and 81.0% with 76.9% diagnostic accuracy. The per patient area under the receiver-operating characteristic curve analysis was 0.81 (0.67-0.95, P<0.0001). CONCLUSIONS: CT-FFR is safe and feasible in patients with severe aortic stenosis. Our data suggests that the diagnostic accuracy of CT-FFR in this cohort potentially enables its use in clinical practice and provides the foundation for future research into the use of CT-FFR for coronary evaluation pre-aortic valve replacement

    Protein Kinase C-beta Dictates B Cell Fate by Regulating Mitochondrial Remodeling, Metabolic Reprogramming, and Heme Biosynthesis

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    PKCĪ²-null (Prkcbāˆ’/āˆ’) mice are severely immunodeficient. Here we show that mice whose B cells lack PKCĪ² failed to form germinal centers and plasma cells, which undermined affinity maturation and antibody production in response to immunization. Moreover, these mice failed to develop plasma cells in response to viral infection. At the cellular level, we have shown that Prkcbāˆ’/āˆ’B cells exhibited defective antigen polarization and mTORC1 signaling. While altered antigen polarization impaired antigen presentation and likely restricted the potential of GC development, defective mTORC1 signaling impaired metabolic reprogramming, mitochondrial remodeling, and heme biosynthesis in these cells, which altogether overwhelmingly opposed plasma cell differentiation. Taken together, our study reveals mechanistic insights into the function of PKCĪ² as a key regulator of B cell polarity and metabolic reprogramming that instructs B cell fate. Lymphocyte activation is associated with major changes in metabolism. Tsui and colleagues demonstrate that PKCĪ² promotes metabolic reprogramming to drive effector fate decision in B cells
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