Exploring Vitamin B1 Cycling and Its Connections to the Microbial Community in the North Atlantic Ocean

Vitamin B1 (thiamin) is an essential coenzyme for all cells. Recent findings from experimental cell biology and genome surveys have shown that thiamin cycling by plankton is far more complex than was previously understood. Many plankton cells cannot produce thiamin (are auxotrophic) and obligately require an exogenous source of thiamin or one or more of 5 different thiamin-related compounds (TRCs). Despite this emerging evidence for the evolution among plankton of complex interactions related to thiamin, the influence of TRCs on plankton community structure and productivity are not understood. We report measurements of three dissolved TRCs 4-amino-5-aminomethyl-2-methylpyrimidine (AmMP), 5-(2-hydroxyethyl)-4-methyl-1,3-thiazole-2-carboxylic acid (cHET), and 4-methyl-5-thiazoleethanol (HET) that have never before been assayed in seawater. Here we characterize them alongside other TRCs that were measured previously [thiamin and 4-amino-5-hydroxymethyl-2-methylpyrimidine (HMP)], in depth profiles from a latitudinal transect in the north Atlantic in March 2018. TRC concentrations ranged from femptomolar to picomolar. Surface depletion relative to a maximum near the bottom of the euphotic zone and low concentrations at deeper depths were consistent features. Our observations suggest that when bacterial abundance and production are low, TRC concentrations approach a steady state where TRC production and consumption terms are balanced. Standing stocks of TRCs also appear to be positively correlated with bacterial production. However, near the period of peak biomass in the accumulation phase of a bloom we observed an inverse relationship between TRCs and bacterial production, coincident with an increased abundance of Flavobacteria that comparative genomics indicates could be vitamin B1 auxotrophs. While these observations suggest that the dissolved pool of TRCs is often at steady state, with TRC production and consumption balanced, our data suggests that bloom induced shifts in microbial community structure and activity may cause a decoupling between TRC production and consumption, leading to increased abundances of some populations of bacteria that are putatively vitamin B1 auxotrophs

Non-productive angiogenesis disassembles Aß plaque-associated blood vessels

The human Alzheimer’s disease (AD) brain accumulates angiogenic markers but paradoxically, the cerebral microvasculature is reduced around Aß plaques. Here we demonstrate that angiogenesis is started near Aß plaques in both AD mouse models and human AD samples. However, endothelial cells express the molecular signature of non-productive angiogenesis (NPA) and accumulate, around Aß plaques, a tip cell marker and IB4 reactive vascular anomalies with reduced NOTCH activity. Notably, NPA induction by endothelial loss of presenilin, whose mutations cause familial AD and which activity has been shown to decrease with age, produced a similar vascular phenotype in the absence of Aß pathology. We also show that Aß plaque-associated NPA locally disassembles blood vessels, leaving behind vascular scars, and that microglial phagocytosis contributes to the local loss of endothelial cells. These results define the role of NPA and microglia in local blood vessel disassembly and highlight the vascular component of presenilin loss of function in AD

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

Annotated bibliography of Salomon de la Selva\u27s collected poems

The purpose of my project is to provide a compilation of the work of Nicaraguan born poet, Salomon De la Selva, who incidentally was nominated for a Nobel Prize in 1919, and was the first Latin-American poet to publish extensively in English. In order to achieve this goal, my research methods included the substantial use of the Internet, as well as two investigative trips to Mexico and one to Nicaragua, which ultimately led me to uncover a total of 135 unaccounted English-language poems. In addition, De la Selva\u27s uniqueness lies in the fact that he was a truly bilingual writer, who was equally able to create both in English and Spanish, simultaneously. Therefore, my project not only represents an act of reclamation, but the new material also provides new exciting possibilities for his work by facilitating an intertextual analysis of his poems, which will aid in understanding the complexities of bilingualism

Functional and structural characterisation of RimL from Bacillus cereus, a new Nα-acetyltransferase of ribosomal proteins that was wrongly assigned as an aminoglycosyltransferase

Enzymes of the GNAT (GCN5-relate N-acetyltransferases) superfamily are important regulators of cell growth and development. They are functionally diverse and share low amino acid sequence identity, making functional annotation difficult. In this study, we report the function and structure of a new ribosomal enzyme, N-acetyl transferase from Bacillus cereus (RimL), a protein that was previously wrongly annotated as an aminoglycosyltransferase. Firstly, extensive comparative amino acid sequence analyses suggested RimL belongs to a cluster of proteins mediating acetylation of the ribosomal protein L7/L12. To assess if this was the case, several well established substrates of aminoglycosyltransferases were screened. The results of these studies did not support an aminoglycoside acetylating function for RimL. To gain further insight into RimL biological role, a series of studies that included MALDI-TOF, isothermal titration calorimetry, NMR, X-ray protein crystallography, and site-directed mutagenesis confirmed RimL affinity for Acetyl-CoA and that the ribosomal protein L7/L12 is a substrate of RimL. Last, we advance a mechanistic model of RimL mode of recognition of its protein substrates. Taken together, our studies confirmed RimL as a new ribosomal N-acetyltransferase and provide structural and functional insights into substrate recognition by N-acetyltransferases and protein acetylation in bacteria.Dr. Petra Pernot, beamline BM29 European Synchrotron Radiation Facility (ESRF) and Dr. Ed Lowe, Dept. of Biochemistry, University of Oxford for their help in SAXS data collection. Dr. David Staunton, Dept. of Biochemistry, University of Oxford for his help in SEC-MALS data collection

Automated task training and longitudinal monitoring of mouse mesoscale cortical circuits using home cages

We report improved automated open-source methodology for head-fixed mesoscale cortical imaging and/or behavioral training of home cage mice using Raspberry Pi-based hardware. Staged partial and probabilistic restraint allows mice to adjust to self-initiated headfixation over 3 weeks' time with similar to 50% participation rate. We support a cue-based behavioral licking task monitored by a capacitive touch-sensor water spout. While automatically head-fixed, we acquire spontaneous, movement-triggered, or licking task-evoked GCaMP6 cortical signals. An analysis pipeline marked both behavioral events, as well as analyzed brain fluorescence signals as they relate to spontaneous and/or task-evoked behavioral activity. Mice were trained to suppress licking and wait for cues that marked the delivery of water. Correct rewarded go-trials were associated with widespread activation of midline and lateral barrel cortex areas following a vibration cue and delayed frontal and lateral motor cortex activation. Cortical GCaMP signals predicted trial success and correlated strongly with trial-outcome dependent body movements

Targeted ischemic stroke induction and mesoscopic imaging assessment of blood flow and ischemic depolarization in awake mice

Despite advances in experimental stroke models, confounding factors such as anesthetics used during stroke induction remain. Furthermore, imaging of blood flow during stroke is not routinely done. We take advantage of in vivo bihemispheric transcranial windows for longitudinal mesoscopic imaging of cortical function to establish a protocol for focal ischemic stroke induction in target brain regions using photothrombosis in awake head-fixed mice. Our protocol does not require any surgical steps at the time of stroke induction or anesthetics during either head fixation or photoactivation. In addition, we performed laser speckle contrast imaging and wide-field calcium imaging to reveal the effect of cortical spreading ischemic depolarization after stroke in both anesthetized and awake animals over a spatial scale encompassing both hemispheres. With our combined approach, we observed ischemic depolarizing waves (3 to 5 mm/min) propagating across the cortex 1 to 5 min after stroke induction in genetically encoded calcium indicator mice. Measures of blood flow by laser speckle were correlated with neurological impairment and lesion volume, suggesting a metric for reducing experimental variability. The ability to follow brain dynamics immediately after stroke as well as during recovery may provide a valuable guide to develop activity-dependent therapeutic interventions to be performed shortly after stroke induction. (C) 2017 Society of Photo-Optical Instrumentation Engineers (SPIE