Light management by algal aggregates in living photosynthetic hydrogels.

Rapid progress in algal biotechnology has triggered a growing interest in hydrogel-encapsulated microalgal cultivation, especially for the engineering of functional photosynthetic materials and biomass production. An overlooked characteristic of gel-encapsulated cultures is the emergence of cell aggregates, which are the result of the mechanical confinement of the cells. Such aggregates have a dramatic effect on the light management of gel-encapsulated photobioreactors and hence strongly affect the photosynthetic outcome. To evaluate such an effect, we experimentally studied the optical response of hydrogels containing algal aggregates and developed optical simulations to study the resultant light intensity profiles. The simulations are validated experimentally via transmittance measurements using an integrating sphere and aggregate volume analysis with confocal microscopy. Specifically, the heterogeneous distribution of cell aggregates in a hydrogel matrix can increase light penetration while alleviating photoinhibition more effectively than in a flat biofilm. Finally, we demonstrate that light harvesting efficiency can be further enhanced with the introduction of scattering particles within the hydrogel matrix, leading to a fourfold increase in biomass growth. Our study, therefore, highlights a strategy for the design of spatially efficient photosynthetic living materials that have important implications for the engineering of future algal cultivation systems.

Conserved cobalamin acquisition protein 1 is essential for vitamin B12 uptake in both Chlamydomonas and Phaeodactylum.

Microalgae play an essential role in global net primary productivity and global biogeochemical cycling. Despite their phototrophic lifestyle, over half of algal species depend for growth on acquiring an external supply of the corrinoid vitamin B12 (cobalamin), a micronutrient produced only by a subset of prokaryotic organisms. Previous studies have identified protein components involved in vitamin B12 uptake in bacterial species and humans. However, little is known about its uptake in algae. Here, we demonstrate the essential role of a protein, cobalamin acquisition protein 1 (CBA1), in B12 uptake in Phaeodactylum tricornutum using CRISPR-Cas9 to generate targeted knockouts and in Chlamydomonas reinhardtii by insertional mutagenesis. In both cases, CBA1 knockout lines could not take up exogenous vitamin B12. Complementation of the C. reinhardtii mutants with the wild-type CBA1 gene restored B12 uptake, and regulation of CBA1 expression via a riboswitch element enabled control of the phenotype. When visualized by confocal microscopy, a YFP-fusion with C. reinhardtii CBA1 showed association with membranes. Bioinformatics analysis found that CBA1-like sequences are present in all major eukaryotic phyla. In algal taxa, the majority that encoded CBA1 also had genes for B12-dependent enzymes, suggesting CBA1 plays a conserved role. Our results thus provide insight into the molecular basis of algal B12 acquisition, a process that likely underpins many interactions in aquatic microbial communities.

Beyond Infection: Mortality and End-of-Life Care Associated with Infectious Disease Consultation in an Academic Health System.

BACKGROUND: Infectious diseases (ID) physicians are increasingly faced with the challenge of caring for patients with terminal illnesses or incurable infections. METHODS: This was a retrospective cohort of all patients with an ID consult within an academic health system 1/1/2014 - 12/31/2023, including community, general, and transplant ID consult services. RESULTS: There were 60,820 inpatient ID consults (17,235 community, 29,999 general, and 13,586 transplant) involving 37,848 unique patients. The number of consults increased by 94% and the rate rose from 5.0 to 9.9 consults per 100 inpatients (p<0.001). In total, 7.5% of patients receiving an ID consult died during admission, and 1,006 (2.6%) of patients were discharged to hospice. In-hospital mortality was 5.2% for community ID, 7.8% for general ID, and 10.7% for transplant ID patients (p<0.001). Six-month mortality was 9% for all non-obstetric admissions, , vs. 19% for community ID, 20.9% for general ID, and 22.3% for transplant ID.In total 2,866 (7.6%) of all patients receiving ID consultation also received palliative care consultation during the same hospitalization. The index ID consult preceded any palliative consult in the majority (69.5%) of cases. 16.3% of patients had a do-not-resuscitate order during the index hospitalization. 12.2% of all patients with a do-not-resuscitate order had this placed on the same day as the ID consult. CONCLUSIONS: Patients receiving ID consultation were increasingly complex and more likely to die soon after consultation. These results provide a framework for ID clinicians to consider their role in end-of-life care.

Clinical outcomes in patients with piperacillin/tazobactam-non-susceptible but ceftriaxone-susceptible E. coli or K. pneumoniae bloodstream infection.

BACKGROUND: A small proportion of Escherichia coli and Klebsiella pneumoniae demonstrate in vitro non-susceptibility to piperacillin/tazobactam but retain susceptibility to ceftriaxone. Uncertainty remains regarding how best to treat these isolates. OBJECTIVES: We sought to compare clinical outcomes between patients with piperacillin/tazobactam-non-susceptible but ceftriaxone-susceptible E. coli or K. pneumoniae bloodstream infection receiving definitive therapy with ceftriaxone versus an alternative effective antibiotic. METHODS: We retrospectively identified patients with a positive blood culture for piperacillin/tazobactam-non-susceptible but ceftriaxone-susceptible E. coli or K. pneumoniae between 1 January 2013 and 31 December 2022. Patients were divided into one of two definitive treatment groups: ceftriaxone or alternative effective antibiotic. Our primary outcome was a composite of 90 day all-cause mortality, hospital readmission, or recurrence of infection. We used Cox proportional hazards models to compare time with the composite outcome between groups. RESULTS: Sixty-two patients were included in our analysis. Overall, median age was 63 years (IQR 49.5-71.0), the most common source of infection was intra-abdominal (25/62; 40.3%) and the median total duration of therapy was 12.0 days (IQR 9.0-16.8). A total of 9/22 (40.9%) patients in the ceftriaxone treatment group and 18/40 (45.0%) patients in the alternative effective antibiotic group met the composite endpoint. In an adjusted time-to-event analysis, there was no difference in the composite endpoint between groups (HR 0.67, 95% CI 0.30-1.50). The adjusted Bayesian posterior probability that the HR was less than or equal to 1 (i.e. ceftriaxone is as good or better than alternative therapy) was 85%. CONCLUSIONS: These findings suggest that ceftriaxone can be used to effectively treat bloodstream infections with E. coli or K. pneumoniae that are non-susceptible to piperacillin/tazobactam but susceptible to ceftriaxone.

MultiCenter Study of Intra-Abdominal Abscess Formation After Major Operative Hepatic Trauma.

INTRODUCTION: One of the significant complications of operative liver trauma is intra-abdominal abscesses (IAA). The objective of this study was to determine risk factors associated with postoperative IAA in surgical patients with major operative liver trauma. METHODS: A retrospective multi-institutional study was performed at 13 Level 1 and Level 2 trauma centers from 2012 to 2021. Adult patients with major liver trauma (grade 3 and higher) requiring operative management were enrolled. Univariate and multivariate analyses were performed. RESULTS: Three hundred seventy-two patients were included with 21.2% (n = 79/372) developing an IAA. No difference was found for age, gender, injury severity score, liver injury grade, and liver resections in patients between the groups (P > 0.05). Penetrating mechanism of injury (odds ratio (OR) 3.42, 95% confidence interval (CI) 1.54-7.57, P = 0.02), intraoperative massive transfusion protocol (OR 2.43, 95% CI 1.23-4.79, P = 0.01), biloma/bile leak (OR 2.14, 95% CI 1.01-4.53, P = 0.04), hospital length of stay (OR 1.04, 95% CI 1.02-1.06, P < 0.001), and additional intra-abdominal injuries (OR 2.27, 95% CI 1.09-4.72, P = 0.03) were independent risk factors for IAA. Intra-abdominal drains, damage control laparotomy, total units of packed red blood cells, number of days with an open abdomen, total abdominal surgeries, and blood loss during surgery were not found to be associated with a higher risk of IAA. CONCLUSIONS: Patients with penetrating trauma, massive transfusion protocol activation, longer hospital length of stay, and injuries to other intra-abdominal organs were at higher risk for the development of an IAA following operative liver trauma. Results from this study could help to refine existing guidelines for managing complex operative traumatic liver injuries.

Applying the Milan models to setting analytical performance specifications - considering all the information.

Analytical performance specifications (APS) are used for decisions about the required analytical quality of pathology tests to meet clinical needs. The Milan models, based on clinical outcome, biological variation, or state of the art, were developed to provide a framework for setting APS. An approach has been proposed to assign each measurand to one of the models based on a defined clinical use, physiological control, or an absence of quality information about these factors. In this paper we propose that in addition to such assignment, available information from all models should be considered using a risk-based approach that considers the purpose and role of the actual test in a clinical pathway and its impact on medical decisions and clinical outcomes in addition to biological variation and the state-of-the-art. Consideration of APS already in use and the use of results in calculations may also need to be considered to determine the most appropriate APS for use in a specific setting.

The influence of antenatal imaging on prenatal bonding in uncomplicated pregnancies: a mixed methods analysis.

BACKGROUND: Prenatal bonding describes the emotional connection expectant parents form to their unborn child. Research acknowledges the association between antenatal imaging and enhanced bonding, but the influencing factors are not well understood, particularly for fathers or when using advanced techniques like fetal magnetic resonance imaging (MRI). This study aimed to identify variables which may predict increased bonding after imaging. METHODS: First-time expectant parents (mothers = 58, fathers = 18) completed a two-part questionnaire (QualtricsXM™) about their expectations and experiences of ultrasound (n = 64) or fetal MRI (n = 12) scans in uncomplicated pregnancies. A modified version of the Prenatal Attachment Inventory (PAI) was used to measure bonding. Qualitative data were collected through open-ended questions. Multivariate linear regression models were used to identify significant parent and imaging predictors for bonding. Qualitative content analysis of free-text responses was conducted to further understand the predictors' influences. RESULTS: Bonding scores were significantly increased after imaging for mothers and fathers (p < 0.05). MRI-parents reported significantly higher bonding than ultrasound-parents (p = 0.02). In the first regression model of parent factors (adjusted R2 = 0.17, F = 2.88, p < 0.01), employment status (ß = -0.38, p < 0.05) was a significant predictor for bonding post-imaging. The second model of imaging factors (adjusted R2 = 0.19, F = 3.85, p < 0.01) showed imaging modality (ß = -0.53), imaging experience (ß = 0.42) and parental excitement after the scan (ß = 0.29) were significantly (p < 0.05) associated with increased bonding. Seventeen coded themes were generated from the qualitative content analysis, describing how scans offered reassurance about fetal wellbeing and the opportunity to connect with the baby through quality interactions with imaging professionals. A positive scan experience helped parents to feel excited about parenthood. Fetal MRI was considered a superior modality to ultrasound. CONCLUSIONS: Antenatal imaging provides reassurance of fetal development which affirms parents' emotional investment in the pregnancy and supports the growing connection. Imaging professionals are uniquely positioned to provide parent-centred experiences which may enhance parental excitement and facilitate bonding.

The National Health Service urgent cancer referral pathway for suspected urological cancers: early economic evaluation of a risk prediction test.

OBJECTIVES: In the UK, the number of patients urgently referred for suspected cancer is increasing, and providers are struggling to cope with demand. We explore the potential cost-effectiveness of a new risk prediction test - the PinPoint test - to triage and prioritize patients urgently referred with suspected urological cancers. METHODS: Two simulation models were developed to reflect the diagnostic pathways for patients with (i) suspected prostate cancer, and (ii) bladder or kidney cancer, comparing the PinPoint test to current practice. An early economic analysis was conducted from a UK National Health Service (NHS) perspective. The primary outcomes were the percentage of individuals seen within 2 weeks and health care costs. An exploratory analysis was conducted to understand the potential impact of the Pinpoint test on quality-adjusted life years gained. RESULTS: Across both models and applications, the PinPoint test led to more individuals with urological cancer being seen within 2 weeks. Using PinPoint only to prioritize patients led to increased costs overall, whereas using PinPoint to both triage and prioritize patients led to cost savings. The estimated impact on life years gained/lost was very small and highly uncertain. CONCLUSIONS: Using the PinPoint test to prioritize urgent referrals meant that more individuals with urological cancer were seen within 2 weeks, but at additional cost to the NHS. If used as a triage and prioritization tool, the PinPoint test shortens wait times for referred individuals and is cost saving. More data on the impact of short-term delays to diagnosis on health-related quality of life is needed.

First Report With Medium-term Follow-up of Intestinal Transplantation for Advanced and Recurrent Nonresectable Pseudomyxoma Peritonei.

OBJECTIVE: To report our experience with the combination of radical surgical excision and intestinal transplantation in patients with recurrent pseudomyxoma peritonei (PMP) not amenable to further cytoreductive surgery (CRS). BACKGROUND: CRS and heated intraoperative peritoneal chemotherapy are effective treatments for many patients with PMP. In patients with extensive small bowel involvement or nonresectable recurrence, disease progression results in small bowel obstruction, nutritional failure, and fistulation, with resulting abdominal wall failure. METHODS: Between 2013 and 2022, patients with PMP who had a nutritional failure and were not suitable for further CRS underwent radical debulking and intestinal transplantation at our centre. RESULTS: Fifteen patients underwent radical exenteration of affected intra-abdominal organs and transplantation adapted according to the individual case. Eight patients had isolated small bowel transplantation and 7 patients underwent modified multivisceral transplantation. In addition, in 7 patients with significant abdominal wall tumor involvement, a full-thickness vascularized abdominal wall transplant was performed. Two of the 15 patients died within 90 days due to surgically related complications. Actuarial 1-year and 5-year patient survivals were 79% and 55%, respectively. The majority of the patients had significant improvement in quality of life after transplantation. Progression/recurrence of disease was detected in 91% of patients followed up for more than 6 months. CONCLUSION: Intestinal/multivisceral transplantation enables a more radical approach to the management of PMP than can be achieved with conventional surgical methods and is suitable for patients for whom there is no conventional surgical option. This complex surgical intervention requires the combined skills of both peritoneal malignancy and transplant teams.

Increasing amyloplast size in wheat endosperm through mutation of PARC6 affects starch granule morphology.

The determination of starch granule morphology in plants is poorly understood. The amyloplasts of wheat endosperm contain large discoid A-type granules and small spherical B-type granules. To study the influence of amyloplast structure on these distinct morphological types, we isolated a mutant in durum wheat (Triticum turgidum) defective in the plastid division protein PARC6, which had giant plastids in both leaves and endosperm. Endosperm amyloplasts of the mutant contained more A- and B-type granules than those of the wild-type. The mutant had increased A- and B-type granule size in mature grains, and its A-type granules had a highly aberrant, lobed surface. This morphological defect was already evident at early stages of grain development and occurred without alterations in polymer structure and composition. Plant growth and grain size, number and starch content were not affected in the mutants despite the large plastid size. Interestingly, mutation of the PARC6 paralog, ARC6, did not increase plastid or starch granule size. We suggest TtPARC6 can complement disrupted TtARC6 function by interacting with PDV2, the outer plastid envelope protein that typically interacts with ARC6 to promote plastid division. We therefore reveal an important role of amyloplast structure in starch granule morphogenesis in wheat.

A dominant mutation in ß-AMYLASE1 disrupts nighttime control of starch degradation in Arabidopsis leaves.

Arabidopsis (Arabidopsis thaliana) leaves possess a mechanism that couples the rate of nighttime starch degradation to the anticipated time of dawn, thus preventing premature exhaustion of starch and nighttime starvation. To shed light on the mechanism, we screened a mutagenized population of a starvation reporter line and isolated a mutant that starved prior to dawn. The mutant had accelerated starch degradation, and the rate was not adjusted to time of dawn. The mutation responsible led to a single amino acid change (S132N) in the starch degradation enzyme BETA-AMYLASE1 (BAM1; mutant allele named bam1-2D), resulting in a dominant, gain-of-function phenotype. Complete loss of BAM1 (in bam1-1) did not affect rates of starch degradation, while expression of BAM1(S132N) in bam1-1 recapitulated the accelerated starch degradation phenotype of bam1-2D. In vitro analysis of recombinant BAM1 and BAM1(S132N) proteins revealed no differences in kinetic or stability properties, but in leaf extracts, BAM1(S132N) apparently had a higher affinity than BAM1 for an established binding partner required for normal rates of starch degradation, LIKE SEX FOUR1 (LSF1). Genetic approaches showed that BAM1(S132N) itself is likely responsible for accelerated starch degradation in bam1-2D and that this activity requires LSF1. Analysis of plants expressing BAM1 with alanine or aspartate rather than serine at position 132 indicated that the gain-of-function phenotype is not related to phosphorylation status at this position. Our results strengthen the view that control of starch degradation in wild-type plants involves dynamic physical interactions of degradative enzymes and related proteins with a central role for complexes containing LSF1.

Rising rates of starch degradation during daytime and trehalose 6-phosphate optimize carbon availability.

Many plants, including Arabidopsis (Arabidopsis thaliana), accumulate starch in the light and remobilize it to support maintenance and growth at night. Starch synthesis and degradation are usually viewed as temporally separate processes. Recently, we reported that starch is also degraded in the light. Degradation rates are generally low early in the day but rise with time. Here, we show that the rate of degradation in the light depends on time relative to dawn rather than dusk. We also show that degradation in the light is inhibited by trehalose 6-phosphate, a signal for sucrose availability. The observed responses of degradation in the light can be simulated by a skeletal model in which the rate of degradation is a function of starch content divided by time remaining until dawn. The fit is improved by extension to include feedback inhibition of starch degradation by trehalose 6-phosphate. We also investigate possible functions of simultaneous starch synthesis and degradation in the light, using empirically parameterized models and experimental approaches. The idea that this cycle buffers growth against falling rates of photosynthesis at twilight is supported by data showing that rates of protein and cell wall synthesis remain high during a simulated dusk twilight. Degradation of starch in the light may also counter over-accumulation of starch in long photoperiods and stabilize signaling around dusk. We conclude that starch degradation in the light is regulated by mechanisms similar to those that operate at night and is important for stabilizing carbon availability and signaling, thus optimizing growth in natural light conditions.

Initiation of the Virtual Interview: A 5-Y Evaluation of General Surgery Residency Match Results.

INTRODUCTION: The virtual residency application season posed numerous challenges for the 2021 residency match process. Many residency programs are exploring relationships between this novel format and the match process. The purpose of this study was to compare one of the largest general surgery residency program's applications and match data from preCOVID years to the 2021 virtual cycle. MATERIALS AND METHODS: A retrospective review was performed of applicants to a single general surgery residency program from 2017 to 2021. The primary outcome was the number of locally matched applicants. The secondary outcomes were the total number of applications, change in applicant demographics, and variability of the geographic spread during this study period. Chi-square tests of independence, Fisher's exact tests, and negative binomial regression were performed. RESULTS: 6819 applicants were included in the study. In 2021, an increase in applications was observed. The distribution of 2021 applications was statistically different from previous years regarding gender and race (P < 0.0001). The 2021 application cycle had a greater proportion of applicants from the United States (P < 0.0001) and southern US medical schools (P = 0.008). While the 2021 cycle had significantly more interviews (P = 0.013), there were no significant differences in the demographic composition of interviewees. During the 2021 application year, all 11 matches were from southern medical schools and there was a trend to more matched female applicants compared to previous years. CONCLUSIONS: During the 2021 COVID-19 virtual match cycle, an increase in both the number of applications and number of interviews for general surgery residency was identified. The characteristics of applicants who interviewed and matched were not different when compared to previous years. As virtual interviews may become more commonplace, it is important to assess all factors that may be involved in the dynamic residency application process.

Deterioration Index in Critically Injured Patients: A Feasibility Analysis.

INTRODUCTION: Continuous prediction surveillance modeling is an emerging tool giving dynamic insight into conditions with potential mitigation of adverse events (AEs) and failure to rescue. The Epic electronic medical record contains a Deterioration Index (DI) algorithm that generates a prediction score every 15 min using objective data. Previous validation studies show rapid increases in DI score (≥14) predict a worse prognosis. The aim of this study was to demonstrate the utility of DI scores in the trauma intensive care unit (ICU) population. METHODS: A prospective, single-center study of trauma ICU patients in a Level 1 trauma center was conducted during a 3-mo period. Charts were reviewed every 24 h for minimum and maximum DI score, largest score change (Δ), and AE. Patients were grouped as low risk (ΔDI <14) or high risk (ΔDI ≥14). RESULTS: A total of 224 patients were evaluated. High-risk patients were more likely to experience AEs (69.0% versus 47.6%, P = 0.002). No patients with DI scores <30 were readmitted to the ICU after being stepped down to the floor. Patients that were readmitted and subsequently died all had DI scores of ≥60 when first stepped down from the ICU. CONCLUSIONS: This study demonstrates DI scores predict decompensation risk in the surgical ICU population, which may otherwise go unnoticed in real time. This can identify patients at risk of AE when transferred to the floor. Using the DI model could alert providers to increase surveillance in high-risk patients to mitigate unplanned returns to the ICU and failure to rescue.

The importance of vitamin B12 for individuals choosing plant-based diets.

Vitamin B12 is an essential nutrient that is not made by plants; consequently, unfortified plant-based foods are not a reliable supply. Recent estimates suggest high rates of vitamin B12 deficiency among the vegetarian and vegan populations, particularly in pregnant women or women of child-bearing age who, for ethical and health reasons, are shifting towards higher consumption of plant-based foods in ever-increasing numbers. Vitamin B12 plays crucial metabolic roles across the life-course and in particular during pregnancy and in early development (first 1000 days of life). Evidence now implicates vitamin B12 deficiency with increased risk to a range of neuro, vascular, immune, and inflammatory disorders. However, the current UK recommended nutrient intake for vitamin B12 does not adequately consider the vitamin B12 deficit for those choosing a plant-based diet, including vegetarianism and in particular veganism, representing a hidden hunger. We provide a cautionary note on the importance of preventing vitamin B12 deficits for those individuals choosing a plant-based diet and the health professionals advising them.

Prevalence and Incidence of Pediatric Acute Respiratory Distress Syndrome in a Tertiary Academic PICU in South Africa.

OBJECTIVES: To determine the prevalence and incidence of pediatric acute respiratory distress syndrome (pARDS) among infants and children admitted to the PICU. DESIGN: A single-center descriptive point prevalence study with twice weekly data collection over a 6 months (August 2020 to February 12, 2021). SETTING: Red Cross War Memorial Children's Hospital, Cape Town, South Africa. PATIENTS: All infants and children admitted to the PICU on study days were included. INTERVENTIONS: Data were captured electronically on a standardized case record form using a Research Electronic Data Capture electronic database. MEASUREMENTS AND MAIN RESULTS: The Pediatric Acute Lung Injury Consensus Conference criteria were used to define pARDS cases. Prevalence was calculated as the total number of pARDS cases/1,000 PICU bed days. The study included 354 patients (median [interquartile range]) 10.1 months old (1.5-61.3 mo old), with 204 males (57.6%), who occupied 879 bed days. Of these 879 bed days, 266 (30.3%; 95% CI, 27.2-33.3%) were occupied by pARDS cases, with a calculated prevalence and incidence of 302.6 of 1,000 bed days (30.3%) and 29.7% (95% CI, 26.7-32.7%), respectively. Three cases from the cohort were defined using the oxygen saturation index calculation. In cases receiving invasive ventilation ( n = 494; 56.2%), pARDS severity was classified as mild ( n = 143; 16.3%), moderate ( n = 44; 5.0%), and severe ( n = 29, 3.3%). A further 205 beds (23.3%) were occupied by patients classified as being at risk of pARDS. CONCLUSIONS: The prevalence and incidence of pARDS in a South African PICU appears substantially higher than findings described in international reports. Further investigation of risk factors and outcomes is warranted.

Informed or misinformed consent and use of modified texture diets in dysphagia.

BACKGROUND: Use of modified texture diets-thickening of liquids and modifying the texture of foods-in the hope of preventing aspiration, pneumonia and choking, has become central to the current management of dysphagia. The effectiveness of this intervention has been questioned. We examine requirements for a valid informed consent process for this approach and whether the need for informed consent for this treatment is always understood or applied by practitioners. MAIN TEXT: Valid informed consent requires provision of accurate and balanced information, and that agreement is given freely by someone who knows they have a choice. Current evidence, including surveys of practitioners and patients in different settings, suggests that practice in this area is often inadequate. This may be due to patients' communication difficulties but also poor communication-and no real attempt to obtain consent-by practitioners before people are 'put on' modified texture diets. Even where discussion occurs, recommendations may be influenced by professional misconceptions about the efficacy of this treatment, which in turn may poison the well for the informed consent process. Patients cannot make appropriate decisions for themselves if the information provided is flawed and unbalanced. The voluntariness of patients' decisions is also questionable if they are told 'you must', when 'you might consider' is more appropriate. Where the decision-making capacity of patients is in question, inappropriate judgements and recommendations may be made by substitute decision makers and courts unless based on accurate information. CONCLUSION: Research is required to examine the informed consent processes in different settings, but there is ample reason to suggest that current practice in this area is suboptimal. Staff need to reflect on their current practice regarding use of modified texture diets with an awareness of the current evidence and through the 'lens' of informed consent. Education is required for staff to clarify the importance of, and requirements for, valid informed consent and for decision making that reflects people's preferences and values.

Introduction of glucan synthase into the cytosol in wheat endosperm causes massive maltose accumulation and represses starch synthesis.

We expressed a bacterial glucan synthase (Agrobacterium GlgA) in the cytosol of developing endosperm cells in wheat grains, to discover whether it could generate a glucan from cytosolic ADP-glucose. Transgenic lines had high glucan synthase activity during grain filling, but did not accumulate glucan. Instead, grains accumulated very high concentrations of maltose. They had large volumes during development due to high water content, and very shrivelled grains at maturity. Starch synthesis was severely reduced. We propose that cytosolic glucan synthesized by the glucan synthase was immediately hydrolysed to maltose by cytosolic ß-amylase(s). Maltose accumulation resulted in a high osmotic potential in developing grain, drawing in excess water that stretched the seed coat and pericarp. Loss of water during grain maturation then led to shrinkage when the grains matured. Maltose accumulation is likely to account for the reduced starch synthesis in transgenic grains, through signalling and toxic effects. Using bioinformatics, we identify an isoform of ß-amylase likely to be responsible for maltose accumulation. Removal of this isoform through identification of TILLING mutants or genome editing, combined with co-expression of heterologous glucan synthase and a glucan branching enzyme, may in future enable elevated yields of carbohydrate through simultaneous accumulation of starch and cytosolic glucan.

Cycloserine and Linezolid for Tuberculosis Meningitis: Pharmacokinetic Evidence of Potential Usefulness.

BACKGROUND: The ability of antituberculosis drugs to cross the blood-brain barrier and reach the central nervous system is critical to their effectiveness in treating tuberculosis meningitis (TBM). We sought to fill a critical knowledge gap by providing data on the ability of new and repurposed antituberculosis drugs to penetrate into the cerebrospinal fluid (CSF). METHODS: We conducted a clinical pharmacology study among patients treated for TBM in Tbilisi, Georgia, from January 2019 until January 2020. Serial serum and CSF samples were collected while patients were hospitalized. CSF was collected from routine lumbar punctures with the timing of the lumbar puncture alternating between 2 and 6 hours to capture early and late CSF penetration. RESULTS: A total of 17 patients treated for TBM (8 with confirmed disease) were included; all received linezolid, with a subset receiving cycloserine (5), clofazimine (5), delamanid (4), and bedaquiline (2). All CSF measurements of bedaquiline (12), clofazimine (24), and delamanid (19) were below the limit of detection. The median CSF concentrations of cycloserine at 2 and 6 hours were 15.90 and 15.10 µg/mL with adjusted CSF/serum ratios of 0.52 and 0.66. CSF concentrations of linezolid were 0.90 and 3.14 µg/mL at 2 and 6 hours, with adjusted CSF/serum ratios of 0.25 and 0.59, respectively. CSF serum linezolid concentrations were not affected by rifampin coadministration. CONCLUSIONS: Based on moderate to high CSF penetration, linezolid and cycloserine may be effective drugs for TBM treatment, whereas the utility of bedaquiline, delamanid, and clofazimine is uncertain given their low CSF penetration.

Exploring the onset of B12 -based mutualisms using a recently evolved Chlamydomonas auxotroph and B12 -producing bacteria.

Cobalamin (vitamin B12 ) is a cofactor for essential metabolic reactions in multiple eukaryotic taxa, including major primary producers such as algae, and yet only prokaryotes can produce it. Many bacteria can colonize the algal phycosphere, forming stable communities that gain preferential access to photosynthate and in return provide compounds such as B12 . Extended coexistence can then drive gene loss, leading to greater algal-bacterial interdependence. In this study, we investigate how a recently evolved B12 -dependent strain of Chlamydomonas reinhardtii, metE7, forms a mutualism with certain bacteria, including the rhizobium Mesorhizobium loti and even a strain of the gut bacterium E. coli engineered to produce cobalamin. Although metE7 was supported by B12 producers, its growth in co-culture was slower than the B12 -independent wild-type, suggesting that high bacterial B12 provision may be necessary to favour B12 auxotrophs and their evolution. Moreover, we found that an E. coli strain that releases more B12 makes a better mutualistic partner, and although this trait may be more costly in isolation, greater B12 release provided an advantage in co-cultures. We hypothesize that, given the right conditions, bacteria that release more B12 may be selected for, particularly if they form close interactions with B12 -dependent algae.