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C4 photosynthesis is an adaptive photosynthetic pathway which concentrates CO2 around Rubisco in specialized bundle sheath cells to reduce photorespiration. Historically, the pathway has been characterized into three different subtypes based on the decarboxylase involved, although recent work has provided evidence that some plants can use multiple decarboxylases, with maize in particular using both the NADP-malic enzyme (NADP-ME) pathway and phosphoenolpyruvate carboxykinase (PEPCK) pathway. Parallel C4 pathways could be advantageous in balancing energy and reducing equivalents between bundle sheath and mesophyll cells, in decreasing the size of the metabolite gradients between cells and may better accommodate changing environmental conditions or source to sink demands on growth. The enzyme activity of C4 decarboxylases can fluctuate with different stages of leaf development, but it remains unclear if the pathway flexibility is an innate aspect of leaf development or an adaptation to the leaf microenvironment that is regulated by the plant. In this study, variation in the two C4 pathways in maize were characterized at nine plant ages throughout the life cycle. Two positions in the canopy were examined for variation in physiology, gene expression, metabolite concentration, and enzyme activity, with particular interest in asparagine as a potential regulator of C4 decarboxylase activity. Variation in C4 and C3 metabolism was observed for both leaf age and canopy position, reflecting the ability of C4 pathways to adapt to changing microenvironments.One Sentence SummaryThe proportion of the two C4 pathways in maize plants is dependent on canopy position and not the age of the leaf.

© 2017 Wiley Periodicals, Inc. Occurring in at least 1 in 3,000 live births, chromosome 22q11.2 deletion syndrome (22q11DS) produces a complex phenotype that includes a constellation of medical complications such as congenital cardiac defects, immune deficiency, velopharyngeal dysfunction, and characteristic facial dysmorphic features. There is also an increased incidence of psychiatric diagnosis, especially intellectual disability and ADHD in childhood, lifelong anxiety, and a strikingly high rate of schizophrenia spectrum disorders, which occur in around 30% of adults with 22q11DS. Using innovative computational connectomics, we studied how 22q11DS affects high-level network signatures of hierarchical modularity and its intrinsic geometry in 55 children with confirmed 22q11DS and 27 Typically Developing (TD) children. Results identified 3 subgroups within our 22q11DS sample using a K-means clustering approach based on several midline structural measures-of-interests. Each subgroup exhibited distinct patterns of connectome abnormalities. Subtype 1, containing individuals with generally healthy-looking brains, exhibited no significant differences in either modularity or intrinsic geometry when compared with TD. By contrast, the more anomalous 22q11DS Subtypes 2 and 3 brains revealed significant modular differences in the right hemisphere, while Subtype 3 (the most anomalous anatomy) further exhibited significantly abnormal connectome intrinsic geometry in the form of left–right temporal disintegration. Taken together, our findings supported an overall picture of (a) anterior-posteriorly differential interlobar frontotemporal/frontoparietal dysconnectivity in Subtypes 2 and 3 and (b) differential intralobar dysconnectivity in Subtype 3. Our ongoing studies are focusing on whether these subtypes and their connnectome signatures might be valid biomarkers for predicting the degree of psychosis-proneness risk found in 22q11DS. Hum Brain Mapp 39:232–248, 2018. © 2017 Wiley Periodicals, Inc.

AIMS: To investigate the hypothesis that increasing alcohol consumption is accompanied by increasing use of acute, but decreasing use of preventative, medical services among the general population. DESIGN AND PARTICIPANTS: Health and life-style survey of 41,000 randomly-sampled adults in SE England who self-completed a validated questionnaire covering socio-demographics, alcohol and tobacco usage and use of acute (A&E department and general practitioner) and preventative (dental, optician, mammography and cervical cytology) services: the response rate was 60%. MEASUREMENTS: Comparative use of acute and preventative health care services by patients with varying consumption of alcoholic beverages. This was estimated by the odds ratio for service use, after correcting for the following confounding variables; age, social class, ethnic group, employment status, whether lives with children or with other adults, whether is a career, limiting long-term illness, depression status, smoking habit and use of private health insurance. FINDINGS: There was increased use of accident and emergency services by the harmful and intermediate drinking groups compared with the safe drinking group. Male abstainers attended their A&E departments more frequently than 'safe limit' drinkers. With respect to preventative services, both male and female abstainers and harmful drinkers used dental services less than safe limit drinkers. For females, mammography and cervical cytology services were less frequently used by abstainers and by harmful drinkers. CONCLUSIONS: This study supports the generally held view that heavy alcohol consumers are disproportionate users of acute medical services but they are relative under-users of preventative medical care services. Alcohol abstainers are also over-users of acute services, but under-users of preventative services. These latter observations are relevant to the claims that moderate alcohol consumers have lower apparent morbidity and mortality rates compared to abstainers.

The misaligned undulating membrane (mum) mutant of Tetrahymena thermophila is a non-conditional, single gene recessive mutation. The major effect of the mum mutation is the production of multiple undulating membrane (UM) fragments in the oral apparatus (OA). The ultrastructure of the UM fragments of mum OAs is identical to that of the single UM of wild-type OAs. Analysis of OA development at midbody using a combination of light microscopy of protargol-stained cells and SEM of demembranated whole cells showed that the phenotypic effect of the mum mutation first becomes evident during mid to late stage 4 and is fully manifested in early stage 5. The effect of the mutation involves a proliferation of excess basal bodies in the UM field. Subsequent events in the development of the mum OA from mid to late stage 5 are identical to those in wild-type OAs. This study suggests that the mum mutation establishes conditions that allow the production of multiple UMs and thus reveals that the UM field is competent for the complete and coordinated development of several adjacent UMs. This level of regional control is not clearly evident when a single UM is present. The comparison of development of wild-type and mum OAs required an extensive reanalysis of stages 4 and 5 of normal oral development. On the basis of current and previous observations, we propose a new and more subdivided staging system for oral development in Tetrahymena.