Nitrogen acquisition by roots: physiological and developmental mechanisms ensuring plant adaptation to a fluctuating resource

International audienceNitrogen (N) is one of the key mineral nutrients for plants and its availability has a major impact on their growth and development. Most often N resources are limiting and plants have evolved various strategies to modulate their root uptake capacity to compensate for both spatial and temporal changes in N availability in soil. The main N sources for terrestrial plants in soils of temperate regions are in decreasing order of abundance, nitrate, ammonium and amino acids. N uptake systems combine, for these different N forms, high- and low-affinity transporters belonging to multige families. Expression and activity of most uptake systems are regulated locally by the concentration of their substrate, and by a systemic feedback control exerted by whole-plant signals of N status, giving rise to a complex combinatory network. Besides modulation of the capacity of transport systems, plants are also able to modulate their growth and development to maintain N homeostasis. In particular, root system architecture is highly plastic and its changes can greatly impact N acquisition from soil. In this review, we aim at detailing recent advances in the identification of molecular mechanisms responsible for physiological and developmental responses of root N acquisition to changes in N availability. These mechanisms are now unravelled at an increasing rate, especially in the model plant Arabidopsis thaliana L.. Within the past decade, most root membrane transport proteins that determine N acquisition have been identified. More recently, molecular regulators in nitrate or ammonium sensing and signalling have been isolated, revealing common regulatory genes for transport system and root development, as well as a strong connection between N and hormone signalling pathways. Deciphering the complexity of the regulatory networks that control N uptake, metabolism and plant development will help understanding adaptation of plants to sub-optimal N availability and fluctuating environments. It will also provide solutions for addressing the major issues of pollution and economical costs related to N fertilizer use that threaten agricultural and ecological sustainability

Vampires in the village Žrnovo on the island of Korčula: following an archival document from the 18th century

Središnja tema rada usmjerena je na raščlambu spisa pohranjenog u Državnom arhivu u Mlecima (fond: Capi del Consiglio de’ Dieci: Lettere di Rettori e di altre cariche) koji se odnosi na događaj iz 1748. godine u korčulanskom selu Žrnovo, kada su mještani – vjerujući da su se pojavili vampiri – oskvrnuli nekoliko mjesnih grobova. U radu se podrobno iznose osnovni podaci iz spisa te rečeni događaj analizira u širem društvenom kontekstu i prate se lokalna vjerovanja.The main interest of this essay is the analysis of the document from the State Archive in Venice (file: Capi del Consiglio de’ Dieci: Lettere di Rettori e di altre cariche) which is connected with the episode from 1748 when the inhabitants of the village Žrnove on the island of Korčula in Croatia opened tombs on the local cemetery in the fear of the vampires treating. This essay try to show some social circumstances connected with this event as well as a local vernacular tradition concerning superstitions

Optimal Trial Design for Studying Urinary Markers in Bladder Cancer: A Collaborative Review

Urine-based tumor markers are not routinely used in the diagnosis and surveillance of bladder cancer. The main limitation of urinary markers has been a lack of clarity regarding clinical benefit. To review the indications for urinary marker use, barriers to marker utilization, and clinical trial designs for markers available for detection (hematuria populations) and surveillance (bladder cancer populations). The study aim was to facilitate an optimal trial design that could change clinical practice. A PubMed search was conducted on February 17, 2018, using the MeSH search terms “Urinary Bladder Neoplasms” [Mesh] AND “Biomarkers” [Mesh] AND “Urine” [Mesh] yielded 127 articles, of which only two also fulfilled the search term “Randomized Controlled Trial” [Publication Type]. Neither of these two articles examined clinical outcomes for patients but rather focused on the performance characteristics of the urinary marker. For the search terms “Hematuria” [Mesh] AND “Randomized Controlled Trial” [Publication Type] AND “Urinary Bladder Neoplasms” [Mesh] yielded 12 articles, none of which used randomization with the outcome of interest being a clinical endpoint. Several potential designs for urinary marker trials were developed for detection and surveillance of bladder cancer. A marker-based approach compared to usual care for evaluation of hematuria in a primary care setting could reduce unnecessary cystoscopy in patients with low risk and expedite care in patients with higher risk. For bladder cancer surveillance, marker-based approaches could reduce cystoscopy for patients with low-grade disease and potentially improve detection for patients with high risk. Urinary markers are not currently routinely used owing to the absence of level 1 evidence supporting incorporation of urinary markers into protocols for detection or surveillance of bladder cancer. This review provides practical designs for studies that could demonstrate superiority of marker-based approaches over current clinical care. The sample sizes required for these studies are no greater than many of those accrued for previous urinary marker studies, but the proposed trial concepts require planning and a willingness to risk failure of the marker to demonstrate the desired benefits. In this review we discuss current limitations in the use of urinary markers for detection and surveillance of bladder cancer. We identify potential studies that could demonstrate a clinical benefit of the use of markers in improving detection of bladder cancer by reducing evaluation of patients unlikely to have cancer or expediting identification of cancer. For surveillance, a marker trial could improve identification of bladder cancer or reduce cystoscopy in patients with low risk. Urinary markers are not routinely used for detection or surveillance of bladder cancer. This review provides practical designs for studies that could demonstrate superiority of marker-based approaches over current care

Nonaggressive systemic mastocytosis (SM) without skin lesions associated with insect-induced anaphylaxis shows unique features versus other indolent SM

BACKGROUND: Indolent systemic mastocytosis (ISM) without skin lesions (ISMs-) shows a higher prevalence in males, lower serum baseline tryptase levels, and KIT mutation more frequently restricted to bone marrow (BM) mast cells (MCs) than ISM with skin lesions (ISMs+). Interestingly, in almost one-half of ISMs- patients, MC-mediator release episodes are triggered exclusively by insects. OBJECTIVE: We aimed to determine the clinical and laboratory features of ISMs- associated with insect-induced anaphylaxis (insectISMs-) versus other patients with ISM. METHODS: A total of 335 patients presenting with MC activation syndrome, including 143 insectISMs-, 72 ISMs- triggered by other factors (otherISMs-), 56 ISMs+, and 64 nonclonal MC activation syndrome, were studied. RESULTS: Compared with otherISMs- and ISMs+ patients, insectISMs- cases showed marked male predominance (78% vs 53% and 46%; P < .001), a distinct pattern of MC-related symptoms, and significantly lower median serum baseline tryptase levels (22.4 vs 28.7 and 45.8 \u3bcg/L; P 64 .009). Moreover, insectISMs- less frequently presented BM MC aggregates (46% vs 70% and 81%; P 64 .001), and they systematically showed MC-restricted KIT mutation. CONCLUSIONS: ISMs- patients with anaphylaxis triggered exclusively by insects display clinical and laboratory features that are significantly different from other ISM cases, including other ISMs- and ISMs+ patients, suggesting that they represent a unique subgroup of ISM with a particularly low BM MC burden in the absence of adverse prognostic factors