383 research outputs found
Biochemical and molecular characterisation of oenologically important enzymes identified in lactic acid bacteria.
Enzyme concentrates are available for use in commercial wineries to aid in wine processing, or to enhance wine quality. However, pectolytic enzyme remains the sole product routinely used in most wineries. One disadvantage of some of the products currently available commercially is they contain enzymes sourced from microorganisms not usually associated with grape juice or wine, typically fungi such as Aspergillus species. As a result, enzymes are inefficient catalysts under the harsh oenological conditions. In addition, some products contain secondary, and potentially undesirable, contaminant enzyme activities. Clearly there is the potential to develop enzyme preparations specifically for use in grape juice and wine. A potential source of such enzymes are the lactic acid bacteria (LAB), the organisms more commonly associated with the conduct of the malolactic fermentation (MLF) during vinification. In this study, the production of cell-associated enzymes with potential oenological applications by LAB was investigated.
A screening of 50 LAB isolates for the production of lipases, esterases, tannases, and polysaccharide-degrading enzymes revealed wine LAB can produce enzymes of oenological importance. In general, activity towards polysaccharide substrates was more frequent among the lactobacilli and pediococci strains. Lipase activity was observed in three lactobacilli, and all strains were found to have tannase activity. Similarly, all strains displayed some esterase activity, although the activity was markedly stronger among the Oenococcus oeni.
On the basis of the initial screen, a more detailed characterisation of the esterase activity of selected LAB isolates was conducted. Esterase activity was examined across a range of pH, temperature, and ethanol concentrations - all important oenological parameters. In addition, substrate specificity was determined using six ester substrates. In general, activity was maximal at pH values close to 6.0, and temperatures close to 40°C, although exceptions were observed with some strains. Increases in ethanol concentration resulted in lower activity for most lactobacilli and pediococci, but stimulated the esterase activity of all O. oeni.
Work conducted with dairy LAB isolates has suggested esterases may be capable of both hydrolysing and synthesising esters. In the wine industry, the results of some volatile-profiling studies tend to support this theory, with concentrations of esters being reported to both increase and decrease during MLF. Malolactic fermentation trials were conducted in wine with six strains of O. oeni and GCMS was used to quantify particular esters before and after MLF. Some esters were found to increase in concentration during MLF, while others were found to decrease. These findings suggest LAB esterases are in fact capable of both synthesising and hydrolysing ester substrates in wine.
To further dissect the esterase make-up of selected LAB strains, attempts to clone and heterologously express three structural genes for these enzymes were made. Three putative esterase genes were identified in O. oeni and cloned. Sequencing was completed and alignment with published esterase sequences used to reveal theoretical proteins of the O. oeni genes with high homology with those from other organisms. Of note, key features, such as active site motifs, were conserved in each O. oeni sequence.
Expression of the recombinant proteins in E. coli resulted in higher esterase activity in one of the clones compared to the host. These results indicate that the open reading frame of one esterase gene in 0. oeni has been identified.Thesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food and Wine, 200
Neuropathological correlates of dementia in over-80-year-old brain donors from the population-based Cambridge city over-75s cohort (CC75C) study.
Key neuropathological changes associated with late-onset dementia are not fully understood. Population-based longitudinal studies offer an opportunity to step back and examine which pathological indices best link to clinical state. CC75C is a longitudinal study of the population aged 75 and over at baseline in Cambridge, UK. We report on the first 213 participants coming to autopsy with sufficient information for an end of life dementia diagnosis. Clinical diagnosis was ascertained by examining retrospective informant interviews, survey responses, and death certificates according to DSM-IV criteria. The neuropathological protocol was based on the Consortium to Establish a Registry of Alzheimer's Disease (CERAD). Clinical dementia was present in 113 participants (53%): 67% with Alzheimer's disease, 4% vascular dementia, 22% mixed dementia, and 1% dementia with Lewy bodies. As Alzheimer-type pathology was common, the mutually blinded clinical and neuropathological diagnoses were not strongly related. Multivariable analysis identified associations between dementia during life and entorhinal cortex neuritic plaques, hippocampal diffuse plaques, neocortical neurofibrillary tangles, white matter pallor, Lewy bodies, and hippocampal atrophy. These results were consistent in those with clinical Alzheimer's disease. Vascular pathologies, especially microinfarcts, were more common in those with clinical diagnoses including vascular dementia. Alzheimer-type and cerebrovascular pathology are both common in the very old. A greater burden of these pathologies, Lewy bodies, and hippocampal atrophy, are associated with a higher risk of, but do not define, clinical dementia in old age
PRimary Care Opioid Use Disorders treatment (PROUD) trial protocol: a pragmatic, cluster-randomized implementation trial in primary care for opioid use disorder treatment
BACKGROUND: Most people with opioid use disorder (OUD) never receive treatment. Medication treatment of OUD in primary care is recommended as an approach to increase access to care. The PRimary Care Opioid Use Disorders treatment (PROUD) trial tests whether implementation of a collaborative care model (Massachusetts Model) using a nurse care manager (NCM) to support medication treatment of OUD in primary care increases OUD treatment and improves outcomes. Specifically, it tests whether implementation of collaborative care, compared to usual primary care, increases the number of days of medication for OUD (implementation objective) and reduces acute health care utilization (effectiveness objective). The protocol for the PROUD trial is presented here.
METHODS: PROUD is a hybrid type III cluster-randomized implementation trial in six health care systems. The intervention consists of three implementation strategies: salary for a full-time NCM, training and technical assistance for the NCM, and requiring that three primary care providers have DEA waivers to prescribe buprenorphine. Within each health system, two primary care clinics are randomized: one to the intervention and one to Usual Primary Care. The sample includes all patients age 16-90 who visited the randomized primary care clinics from 3 years before to 2 years after randomization (anticipated to be \u3e 170,000). Quantitative data are derived from existing health system administrative data, electronic medical records, and/or health insurance claims ( electronic health records, [EHRs]). Anonymous staff surveys, stakeholder debriefs, and observations from site visits, trainings and technical assistance provide qualitative data to assess barriers and facilitators to implementation. The outcome for the implementation objective (primary outcome) is a clinic-level measure of the number of patient days of medication treatment of OUD over the 2 years post-randomization. The patient-level outcome for the effectiveness objective (secondary outcome) is days of acute care utilization [e.g. urgent care, emergency department (ED) and/or hospitalizations] over 2 years post-randomization among patients with documented OUD prior to randomization.
DISCUSSION: The PROUD trial provides information for clinical leaders and policy makers regarding potential benefits for patients and health systems of a collaborative care model for management of OUD in primary care, tested in real-world diverse primary care settings
New genetic loci implicated in fasting glucose homeostasis and their impact on type 2 diabetes risk.
Levels of circulating glucose are tightly regulated. To identify new loci influencing glycemic traits, we performed meta-analyses of 21 genome-wide association studies informative for fasting glucose, fasting insulin and indices of beta-cell function (HOMA-B) and insulin resistance (HOMA-IR) in up to 46,186 nondiabetic participants. Follow-up of 25 loci in up to 76,558 additional subjects identified 16 loci associated with fasting glucose and HOMA-B and two loci associated with fasting insulin and HOMA-IR. These include nine loci newly associated with fasting glucose (in or near ADCY5, MADD, ADRA2A, CRY2, FADS1, GLIS3, SLC2A2, PROX1 and C2CD4B) and one influencing fasting insulin and HOMA-IR (near IGF1). We also demonstrated association of ADCY5, PROX1, GCK, GCKR and DGKB-TMEM195 with type 2 diabetes. Within these loci, likely biological candidate genes influence signal transduction, cell proliferation, development, glucose-sensing and circadian regulation. Our results demonstrate that genetic studies of glycemic traits can identify type 2 diabetes risk loci, as well as loci containing gene variants that are associated with a modest elevation in glucose levels but are not associated with overt diabetes
Structure-Guided Evolution of Potent and Selective CHK1 Inhibitors through Scaffold Morphing
Pyrazolopyridine inhibitors with low micromolar potency for CHK1 and good selectivity against CHK2 were previously identified by fragment-based screening. The optimization of the pyrazolopyridines to a series of potent and CHK1-selective isoquinolines demonstrates how fragment-growing and scaffold morphing strategies arising from a structure-based understanding of CHK1 inhibitor binding can be combined to successfully progress fragment-derived hit matter to compounds with activity in vivo. The challenges of improving CHK1 potency and selectivity, addressing synthetic tractability, and achieving novelty in the crowded kinase inhibitor chemical space were tackled by multiple scaffold morphing steps, which progressed through tricyclic pyrimido[2,3-b]azaindoles to N-(pyrazin-2-yl)pyrimidin-4-amines and ultimately to imidazo[4,5-c]pyridines and isoquinolines. A potent and highly selective isoquinoline CHK1 inhibitor (SAR-020106) was identified, which potentiated the efficacies of irinotecan and gemcitabine in SW620 human colon carcinoma xenografts in nude mice
Measurement of the cosmic ray spectrum above eV using inclined events detected with the Pierre Auger Observatory
A measurement of the cosmic-ray spectrum for energies exceeding
eV is presented, which is based on the analysis of showers
with zenith angles greater than detected with the Pierre Auger
Observatory between 1 January 2004 and 31 December 2013. The measured spectrum
confirms a flux suppression at the highest energies. Above
eV, the "ankle", the flux can be described by a power law with
index followed by
a smooth suppression region. For the energy () at which the
spectral flux has fallen to one-half of its extrapolated value in the absence
of suppression, we find
eV.Comment: Replaced with published version. Added journal reference and DO
Endothelial and Smooth Muscle Cells from Abdominal Aortic Aneurysm Have Increased Oxidative Stress and Telomere Attrition
Background: Abdominal aortic aneurysm (AAA) is a complex multi-factorial disease with life-threatening complications. AAA is typically asymptomatic and its rupture is associated with high mortality rate. Both environmental and genetic risk factors are involved in AAA pathogenesis. Aim of this study was to investigate telomere length (TL) and oxidative DNA damage in paired blood lymphocytes, aortic endothelial cells (EC), vascular smooth muscle cells (VSMC), and epidermal cells from patients with AAA in comparison with matched controls. Methods: TL was assessed using a modification of quantitative (Q)-FISH in combination with immunofluorescence for CD31 or α-smooth muscle actin to detect EC and VSMC, respectively. Oxidative DNA damage was investigated by immunofluorescence staining for 7, 8-dihydro-8-oxo-2′-deoxyguanosine (8-oxo-dG). Results and Conclusions: Telomeres were found to be significantly shortened in EC, VSMC, keratinocytes and blood lymphocytes from AAA patients compared to matched controls. 8-oxo-dG immunoreactivity, indicative of oxidative DNA damage, was detected at higher levels in all of the above cell types from AAA patients compared to matched controls. Increased DNA double strand breaks were detected in AAA patients vs controls by nuclear staining for γ-H2AX histone. There was statistically significant inverse correlation between TL and accumulation of oxidative DNA damage in blood lymphocytes from AAA patients. This study shows for the first time that EC and VSMC from AAA have shortened telomeres and oxidative DNA damage. Similar findings were obtained with circulating lymphocytes and keratinocytes, indicating the systemic nature of the disease. Potential translational implications of these findings are discussed. © 2012 Cafueri et al
Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory
The Auger Engineering Radio Array (AERA) is part of the Pierre Auger
Observatory and is used to detect the radio emission of cosmic-ray air showers.
These observations are compared to the data of the surface detector stations of
the Observatory, which provide well-calibrated information on the cosmic-ray
energies and arrival directions. The response of the radio stations in the 30
to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of
the incoming electric field. For the latter, the energy deposit per area is
determined from the radio pulses at each observer position and is interpolated
using a two-dimensional function that takes into account signal asymmetries due
to interference between the geomagnetic and charge-excess emission components.
The spatial integral over the signal distribution gives a direct measurement of
the energy transferred from the primary cosmic ray into radio emission in the
AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air
shower arriving perpendicularly to the geomagnetic field. This radiation energy
-- corrected for geometrical effects -- is used as a cosmic-ray energy
estimator. Performing an absolute energy calibration against the
surface-detector information, we observe that this radio-energy estimator
scales quadratically with the cosmic-ray energy as expected for coherent
emission. We find an energy resolution of the radio reconstruction of 22% for
the data set and 17% for a high-quality subset containing only events with at
least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO
Occurrence of an Intersexual Blacktip Shark in the Northern Gulf of Mexico, with Notes on the Standardization of Classifications for This Condition in Elasmobranchs
An intersexual Blacktip Shark Carcharhinus limbatus with a testis, immature female reproductive tracts (embedded), and claspers was caught in the Gulf of Mexico. Histology of the single gonad revealed that all stages of spermatogenesis were occurring; however, the absence of ovaries and a male duct system suggests that neither sex would have been functional in this individual. Intersexuality has been reported in 17 families and 36 species of elasmobranchs. The degree to which the different sexes are present in a given individual is often difficult to categorize by normal hermaphroditic standards, as this is typically an anomalous presentation in elasmobranchs. Therefore, this report provides three categories for classification (basic, incomplete, and complete intersexuality) to standardize terminology and allow for more precise comparisons to be made among elasmobranch examples. Basic intersexuals have gonadal tissue of only one sex and a combination of other male and female characters with neither or only one sex being complete. Incomplete intersexuals have gonadal tissue of both sexes and a combination of other male and female characters; however, neither or only one sex is complete. Complete intersexuals have claspers as well as gonadal tissue and tracts for both sexes. The majority of the reported intersexual elasmobranchs, including the shark described here, are basic intersexuals
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