A Medicago truncatula SWEET transporter implicated in arbuscule maintenance during arbuscular mycorrhizal symbiosis.

Plants form a mutualistic symbiosis with arbuscular mycorrhizal (AM) fungi, which facilitates the acquisition of scarce minerals from the soil. In return, the host plants provide sugars and lipids to its fungal partner. However, the mechanism by which the AM fungi obtain sugars from the plant has remained elusive. In this study we investigated the role of potential SWEET family sugar exporters in AM symbiosis in Medicago truncatula. We show that M. truncatula SWEET1b transporter is strongly upregulated in arbuscule-containing cells compared to roots and localizes to the peri-arbuscular membrane, across which nutrient exchange takes place. Heterologous expression of MtSWEET1b in a yeast hexose transport mutant showed that it mainly transports glucose. Overexpression of MtSWEET1b in M. truncatula roots promoted the growth of intraradical mycelium during AM symbiosis. Surprisingly, two independent Mtsweet1b mutants, which are predicted to produce truncated protein variants impaired in glucose transport, exhibited no significant defects in AM symbiosis. However, arbuscule-specific overexpression of MtSWEET1bY57A/G58D , which are considered to act in a dominant-negative manner, resulted in enhanced collapse of arbuscules. Taken together, our results reveal a (redundant) role for MtSWEET1b in the transport of glucose across the peri-arbuscular membrane to maintain arbuscules for a healthy mutually beneficial symbiosis.

Do final-year medical students have sufficient prescribing competencies? A systematic literature review.

AIMS: Prescribing errors are an important cause of patient safety incidents and are frequently caused by junior doctors. This might be because the prescribing competence of final-year medical students is poor as a result of inadequate clinical pharmacology and therapeutic (CPT) education. We reviewed the literature to investigate which prescribing competencies medical students should have acquired in order to prescribe safely and effectively, and whether these have been attained by the time they graduate. METHODS: PubMed, EMBASE and ERIC databases were searched from the earliest dates up to and including January 2017, using the terms 'prescribing', 'competence' and 'medical students' in combination. Articles describing or evaluating essential prescribing competencies of final-year medical students were included. RESULTS: Twenty-five articles describing, and 47 articles evaluating, the prescribing competencies of final-year students were included. Although there seems to be some agreement, we found no clear consensus among CPT teachers on which prescribing competencies medical students should have when they graduate. Studies showed that students had a general lack of preparedness, self-confidence, knowledge and skills, specifically regarding general and antimicrobial prescribing and pharmacovigilance. However, the results should be interpreted with caution, given the heterogeneity and methodological weaknesses of the included studies. CONCLUSIONS: There is considerable evidence that final-year students have insufficient competencies to prescribe safely and effectively, although there is a need for a greater consensus among CPT teachers on the required competencies. Changes in undergraduate CPT education are urgently required in order to improve the prescribing of future doctors.

Fever without a source in children: international comparison of guidelines.

BACKGROUND: Fever without a source (FWS) in children poses a diagnostic challenge. To distinguish a self-limiting infection from a serious infection, multiple guidelines have been developed to aid physicians in the management of FWS. Currently, there is no comparison of existing FWS guidelines. METHODS: This comparative review describes consistencies and differences in guideline definitions and diagnostic and therapeutic recommendations. A literature search was performed to include secondary care FWS guidelines of high-income countries, composed by national or regional pediatric or emergency care associations, available in English or Dutch. RESULTS: Ten guidelines of five high-income countries were included, with varying age ranges of children with FWS. In children younger than one month with FWS, the majority of the guidelines recommended laboratory testing, blood and urine culturing and antibiotic treatment irrespective of the clinical condition of the patient. Recommendations for blood culture and antibiotic treatment varied for children aged 1-3 months. In children aged above three months, urine culture recommendations were inconsistent, while all guidelines consistently recommended cerebral spinal fluid testing and antibiotic treatment exclusively for children with a high risk of serious infection. CONCLUSIONS: We found these guidelines broadly consistent, especially for children with FWS younger than one month. Guideline variation was seen most in the targeted age ranges and in recommendations for children aged 1-3 months and above three months of age. The findings of the current study can assist in harmonizing guideline development and future research for the management of children with FWS.