Search

Anthropogenic aerosols (AER) and greenhouse gases (GHG)-the leading drivers of the forced historical change-produce different large-scale climate response patterns, with correlations trending from negative to positive over the past century. To understand what caused the time-evolving comparison between GHG and AER response patterns, we apply a low-frequency component analysis to historical surface ocean changes from CESM1 single-forcing large-ensemble simulations. While GHG response is characterized by its first leading mode, AER response consists of two distinct modes. The first one, featuring long-term global AER increase and global cooling, opposes GHG response patterns up to the mid-twentieth century. The second one, featuring multidecadal variations in AER distributions and interhemispheric asymmetric surface ocean changes, appears to reinforce the GHG warming effect over recent decades. AER thus can have both competing and synergistic effects with GHG as their emissions change temporally and spatially., (© 2024. The Author(s).)

Large-scale genomic studies have significantly increased our knowledge of genetic variability across populations. Regional genetic profiling is essential for distinguishing common benign variants from disease-causing ones. To this end, we conducted a comprehensive characterization of exonic variants in the population of Navarre (Spain), utilizing whole genome sequencing data from 358 unrelated individuals of Spanish origin. Our analysis revealed 61,410 biallelic single nucleotide variants (SNV) within the Navarrese cohort, with 35% classified as common (MAF > 1%). By comparing allele frequency data from 1000 Genome Project (excluding the Iberian cohort of Spain, IBS), Genome Aggregation Database, and a Spanish cohort (including IBS individuals and data from Medical Genome Project), we identified 1069 SNVs common in Navarre but rare (MAF ≤ 1%) in all other populations. We further corroborated this observation with a second regional cohort of 239 unrelated exomes, which confirmed 676 of the 1069 SNVs as common in Navarre. In conclusion, this study highlights the importance of population-specific characterization of genetic variation to improve allele frequency filtering in sequencing data analysis to identify disease-causing variants.

In recent decades, there has been a discernible reduction in temperate and Mediterranean grasslands with consequences on the decline of biodiversity and landscape heterogeneity. When this decline is due to agricultural abandonment, a renewed joint management, combining bush clearing by conservationists and grazing by farmers, should favor the maintenance of grasslands, their protected habitats and species and forage production. Rainfall irregularity explains part of the variation of these parameters. To verify these hypotheses, we conduct a comprehensive, multi-scale, multi-taxa study over a ten-year period in a Mediterranean protected area. At the regional scale, experimental plots in which this joint management was implemented are representative of residual managed grasslands of the protected area. At the mesoscale, rainfall irregularity is the main factor explaining inter-annual differences in the biomass of open landscapes, while fauna depends on management, tree cover and trophic resources. At the local scale, in a representative experimental plot, clearing had an immediate negative impact on plant richness and bird and positive on forage. Over a decade, plant biodiversity increased while forage, specialist plants and bird maintained, despite the regrowth of bush. Drought had a negative impact on richness, plant and forage abundance and phenological asynchrony on butterflies. In conclusion, joint management has positive, neutral and negative impacts to be considered before implementing this strategy. This long-term monitoring study draws important lessons for designing a sustainable management of grasslands under abandonment and irregular climate, that should be applied in temperate and Mediterranean regions that are increasingly vulnerable to these trends., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Purpose: To compare topical PHMB (polihexanide) 0.02% (0.2 mg/ml)+ propamidine 0.1% (1 mg/ml) with PHMB 0.08% (0.8 mg/ml)+ placebo (PHMB 0.08%) for Acanthamoeba keratitis (AK) treatment., Design: Prospective, randomized, double-masked, active-controlled, multicenter phase 3 study (ClinicalTrials.gov identifier, NCT03274895)., Participants: One hundred thirty-five patients treated at 6 European centers., Methods: Principal inclusion criteria were 12 years of age or older and in vivo confocal microscopy with clinical findings consistent with AK. Also included were participants with concurrent bacterial keratitis who were using topical steroids and antiviral and antifungal drugs before randomization. Principal exclusion criteria were concurrent herpes or fungal keratitis and use of antiamebic therapy (AAT). Patients were randomized 1:1 using a computer-generated block size of 4. This was a superiority trial having a predefined noninferiority margin. The sample size of 130 participants gave approximately 80% power to detect 20-percentage point superiority for PHMB 0.08% for the primary outcome of the medical cure rate (MCR; without surgery or change of AAT) within 12 months, cure defined by clinical criteria 90 days after discontinuing anti-inflammatory agents and AAT. A prespecified multivariable analysis adjusted for baseline imbalances in risk factors affecting outcomes., Main Outcome Measures: The main outcome measure was MCR within 12 months, with secondary outcomes including best-corrected visual acuity and treatment failure rates. Safety outcomes included adverse event rates., Results: One hundred thirty-five participants were randomized, providing 127 in the full-analysis subset (61 receiving PHMB 0.02%+ propamidine and 66 receiving PHMB 0.08%) and 134 in the safety analysis subset. The adjusted MCR within 12 months was 86.6% (unadjusted, 88.5%) for PHMB 0.02%+ propamidine and 86.7% (unadjusted, 84.9%) for PHMB 0.08%; the noninferiority requirement for PHMB 0.08% was met (adjusted difference, 0.1 percentage points; lower one-sided 95% confidence limit, -8.3 percentage points). Secondary outcomes were similar for both treatments and were not analyzed statistically: median best-corrected visual acuity of 20/20 and an overall treatment failure rate of 17 of 127 patients (13.4%), of whom 8 of 127 patients (6.3%) required therapeutic keratoplasty. No serious drug-related adverse events occurred., Conclusions: PHMB 0.08% monotherapy may be as effective (or at worse only 8 percentage points less effective) as dual therapy with PHMB 0.02%+ propamidine (a widely used therapy) with medical cure rates of more than 86%, when used with the trial treatment delivery protocol in populations with AK with similar disease severity., Financial Disclosure(s): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article., (Copyright © 2023 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Having direct access to brain vasculature, astrocytes can take up available blood nutrients and metabolize them to fulfil their own energy needs and deliver metabolic intermediates to local synapses 1,2 . These glial cells should be, therefore, metabolically adaptable to swap different substrates. However, in vitro and in vivo studies consistently show that astrocytes are primarily glycolytic 3-7 , suggesting glucose is their main metabolic precursor. Notably, transcriptomic data 8,9 and in vitro 10 studies reveal that mouse astrocytes are capable of mitochondrially oxidizing fatty acids and that they can detoxify excess neuronal-derived fatty acids in disease models 11,12 . Still, the factual metabolic advantage of fatty acid use by astrocytes and its physiological impact on higher-order cerebral functions remain unknown. Here, we show that knockout of carnitine-palmitoyl transferase-1A (CPT1A)-a key enzyme of mitochondrial fatty acid oxidation-in adult mouse astrocytes causes cognitive impairment. Mechanistically, decreased fatty acid oxidation rewired astrocytic pyruvate metabolism to facilitate electron flux through a super-assembled mitochondrial respiratory chain, resulting in attenuation of reactive oxygen species formation. Thus, astrocytes naturally metabolize fatty acids to preserve the mitochondrial respiratory chain in an energetically inefficient disassembled conformation that secures signalling reactive oxygen species and sustains cognitive performance., (© 2023. The Author(s).)

Polyploidy is common among grasses ( Poaceae ) and poses challenges for conventional breeding. Genome editing technology circumvents crossing and selfing, enabling targeted modifications to multiple gene copies in a single generation while maintaining the heterozygous context of many polyploid genomes. Bahiagrass ( Paspalum notatum Flüggé; 2 n =4 x =40) is an apomictic, tetraploid C4 species that is widely grown in the southeastern United States as forage in beef cattle production and utility turf. The chlorophyll biosynthesis gene magnesium chelatase ( MgCh ) was selected as a rapid readout target for establishing genome editing in tetraploid bahiagrass. Vectors containing sgRNAs, Cas9 and npt II were delivered to callus cultures by biolistics. Edited plants were characterized through PCR-based assays and DNA sequencing, and mutagenesis frequencies as high as 99% of Illumina reads were observed. Sequencing of wild type (WT) bahiagrass revealed a high level of sequence variation in MgCh likely due to the presence of at least two copies with possibly eight different alleles, including pseudogenes. MgCh mutants exhibited visible chlorophyll depletion with up to 82% reductions in leaf greenness. Two lines displayed progression of editing over time which was linked to somatic editing. Apomictic progeny of a chimeric MgCh editing event were obtained and allowed identification of uniformly edited progeny plants among a range of chlorophyll depletion phenotypes. Sanger sequencing of a highly edited mutant revealed elevated frequency of a WT allele, probably due to frequent homology-directed repair (HDR). To our knowledge these experiments comprise the first report of genome editing applied in perennial, warm-season turf or forage grasses. This technology will accelerate bahiagrass cultivar development., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 May, Sanchez, Gilby and Altpeter.)

The search for new microbicide compounds is of an urgent need, especially against difficult-to-eradicate biofilm-forming bacteria. One attractive option is the application of cationic multivalent dendrimers as antibacterials and also as carriers of active molecules. These compounds require an adequate hydrophilic/hydrophobic structural balance to maximize the effect. Herein, we evaluated the antimicrobial activity of cationic carbosilane (CBS) dendrimers unmodified or modified with polyethylene glycol (PEG) units, against planktonic and biofilm-forming P. aeruginosa culture. Our study revealed that the presence of PEG destabilized the hydrophilic/hydrophobic balance but reduced the antibacterial activity measured by microbiological cultivation methods, laser interferometry and fluorescence microscopy. On the other hand, the activity can be improved by the combination of the CBS dendrimers with endolysin, a bacteriophage-encoded peptidoglycan hydrolase. This enzyme applied in the absence of the cationic CBS dendrimers is ineffective against Gram-negative bacteria because of the protective outer membrane shield. However, the endolysin-CBS dendrimer mixture enables the penetration through the membrane and then deterioration of the peptidoglycan layer, providing a synergic antimicrobial effect.

The purpose of this study is to provide a comprehensive review of the clinical characteristics in chronic Stevens-Johnson syndrome (SJS) patients within the United Kingdom population, their causative factors, treatment profile and prognosis. This retrospective series included 91 patients with chronic SJS treated at Moorfields Eye Hospital (London, United Kingdom). A chart review included visual acuity and presence of clinical findings (including lid abnormalities and ocular surface findings). All medical and surgical treatments were also recorded. Approximately a half of patients were White British but there were significant numbers of patients from other ethnic groups, South Asian and Black in particular. Oral antibiotics were the causative agent in almost a half of the patients with SJS, systemic infections in 14%, non-steroidal anti-inflammatory drugs in 8% and anticonvulsants in 7%. The age of onset was varied but a significant proportion of patients developed acute SJS in childhood. There was a significant correlation between visual acuity at initial referral to final recorded vision. Vision was found to continue to significantly deteriorate over time despite therapeutic interventions. Our regression model shows that ~62% of the variance in final vision can be explained by the initial vision and duration disease. The majority of our patients were on advanced ocular surface treatments including serum drops, topical ciclosporin and retinoic acid drops. Of particular significance, approximately a third of our patient cohort was also on systemic immune suppression. In conclusion, chronic SJS within the UK population under tertiary care remains an area of unmet clinical need. Current medical and surgical modalities prevent worsening of vision in severe ocular disease from SJS., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Jabbour, Din, Logeswaran, Taberno Sanchez and Ahmad.)

Genome editing with sequence-specific nucleases, such as clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9), is revolutionizing crop improvement. Developing efficient genome-editing protocols for highly polyploid crops, including sugarcane ( x = 10-13), remains challenging due to the high level of genetic redundancy in these plants. Here, we report the efficient multiallelic editing of magnesium chelatase subunit I ( MgCh ) in sugarcane. Magnesium chelatase is a key enzyme for chlorophyll biosynthesis. CRISPR/Cas9-mediated targeted co-mutagenesis of 49 copies/alleles of magnesium chelatase was confirmed via Sanger sequencing of cloned PCR amplicons. This resulted in severely reduced chlorophyll contents, which was scorable at the time of plant regeneration in the tissue culture. Heat treatment following the delivery of genome editing reagents elevated the editing frequency 2-fold and drastically promoted co-editing of multiple alleles, which proved necessary to create a phenotype that was visibly distinguishable from the wild type. Despite their yellow leaf color, the edited plants were established well in the soil and did not show noticeable growth retardation. This approach will facilitate the establishment of genome editing protocols for recalcitrant crops and support further optimization, including the evaluation of alternative RNA-guided nucleases to overcome the limitations of the protospacer adjacent motif (PAM) site or to develop novel delivery strategies for genome editing reagents., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Eid, Mohan, Sanchez, Wang and Altpeter.)

The knowledge of the genetic variability of the local population is of utmost importance in personalized medicine and has been revealed as a critical factor for the discovery of new disease variants. Here, we present the Collaborative Spanish Variability Server (CSVS), which currently contains more than 2000 genomes and exomes of unrelated Spanish individuals. This database has been generated in a collaborative crowdsourcing effort collecting sequencing data produced by local genomic projects and for other purposes. Sequences have been grouped by ICD10 upper categories. A web interface allows querying the database removing one or more ICD10 categories. In this way, aggregated counts of allele frequencies of the pseudo-control Spanish population can be obtained for diseases belonging to the category removed. Interestingly, in addition to pseudo-control studies, some population studies can be made, as, for example, prevalence of pharmacogenomic variants, etc. In addition, this genomic data has been used to define the first Spanish Genome Reference Panel (SGRP1.0) for imputation. This is the first local repository of variability entirely produced by a crowdsourcing effort and constitutes an example for future initiatives to characterize local variability worldwide. CSVS is also part of the GA4GH Beacon network. CSVS can be accessed at: http://csvs.babelomics.org/., (© The Author(s) 2020. Published by Oxford University Press on behalf of Nucleic Acids Research.)

Kabuli chickpea is traditionally consumed in Mexico. It is currently exported to countries including United States where its demand has recently increased. In order to demonstrate the effect of thermal processes on the quality of fresh chickpea, the objective of the present work was to evaluate some nutrimental and functional characteristics of raw, steamed and toasted chickpea. The partial chemical composition, total phenols, oligosaccharides, and antioxidant capacities were measured in five genotypes of chickpea. Steamed and toasted chickpea showed up to 8.4 and 25.8% less protein, respectively, than that of raw samples. Oligosaccharides, in general decreased in steamed and toasted fresh grain; however, verbascose increased on average 30.6 and 37.9% in steamed and toasted samples, respectively. Minor changes in total phenolic content were observed a result of the process. Trolox equivalent antioxidant capacity increased up to 3.5 times compared to that of antioxidant capacity of raw samples. Fresh chickpea grain, raw or processed, shows attractive nutritional and antioxidant properties that can contribute to the diet and health of the person who consumes it.

Background/objectives: Infantile hemangiomas (IH) with minimal or arrested growth (MAG) constitute a distinctive subset of IH based on their clinical characteristics and natural history. They are often confused with capillary malformations., Methods: A retrospective observational study has been carried out in which clinical and perinatal characteristics have been evaluated in all IH-MAG evaluated in our Dermatology Department in a 5-year period (January 2013-December 2017)., Results: A total of 14 IH-MAG affecting 13 patients were identified (10 girls and 3 boys). All were born full term, with a mean birth weight of 3448 g for girls vs 3540 g for boys, corresponding to the 72nd percentile for both sexes. The IH-MAG was noticed at birth in 75% of cases. It had a segmental distribution in 6 cases and focal in 8. The most common clinical features was the presence of an erythematous or reticulated background and superficial red bright papules. Lesions were located preferentially in the lower body. Doppler ultrasound showed no significant vascular abnormalities in any case. Five IH-MAG developed ulcerations and three required treatment with propranolol. Progressive involution was observed in all cases., Conclusions: In spite of being a true IH, the absence of a relationship with prematurity, the high birth weight of the newborns, the predominance on the extremities, the higher percentage of segmental lesions, and their reduced ability to proliferate suggest possible etiopathogenic differences compared with conventional IH., (© 2018 Wiley Periodicals, Inc.)

Photoreforming promoted by metal oxide nanophotocatalysts is an attractive route for clean and sustainable hydrogen generation. In the present work, we propose for the first time the use of supported Mn 3 O 4 nanosystems, both pure and functionalized with Au nanoparticles (NPs), for hydrogen generation by photoreforming. The target oxide systems, prepared by chemical vapor deposition (CVD) and decorated with gold NPs by radio frequency (RF) sputtering, were subjected to a thorough chemico-physical characterization and utilized for a proof-of-concept H 2 generation in aqueous ethanolic solutions under simulated solar illumination. Pure Mn 3 O 4 nanosystems yielded a constant hydrogen production rate of 10 mmol h -1 m -2 even for irradiation times up to 20 h. The introduction of Au NPs yielded a significant enhancement in photocatalytic activity, which decreased as a function of irradiation time. The main phenomena causing the Au-containing photocatalyst deactivation have been investigated by morphological and compositional analysis, providing important insights for the design of Mn 3 O 4 -based photocatalysts with improved performances.

In this paper, we address the generation of semantic labels describing the headgear accessories carried out by people in a scene under surveillance, only using depth information obtained from a Time-of-Flight (ToF) camera placed in an overhead position. We propose a new method for headgear accessories classification based on the design of a robust processing strategy that includes the estimation of a meaningful feature vector that provides the relevant information about the people's head and shoulder areas. This paper includes a detailed description of the proposed algorithmic approach, and the results obtained in tests with persons with and without headgear accessories, and with different types of hats and caps. In order to evaluate the proposal, a wide experimental validation has been carried out on a fully labeled database (that has been made available to the scientific community), including a broad variety of people and headgear accessories. For the validation, three different levels of detail have been defined, considering a different number of classes: the first level only includes two classes (hat/cap, and no hat/cap), the second one considers three classes (hat, cap and no hat/cap), and the last one includes the full class set with the five classes (no hat/cap, cap, small size hat, medium size hat, and large size hat). The achieved performance is satisfactory in every case: the average classification rates for the first level reaches 95.25%, for the second one is 92.34%, and for the full class set equals 84.60%. In addition, the online stage processing time is 5.75 ms per frame in a standard PC, thus allowing for real-time operation., Competing Interests: The authors declare no conflict of interest.

Short anagen syndrome is an uncommon and recently described disease characterized by many telogen hairs and short maximum hair length. We report here the case of a 3-year-old girl whose short, sparse, fine hair since birth was consistent with short anagen syndrome. X-ray microanalysis demonstrated normal composition of the main bioelements of her hairs., (© 2017 Wiley Periodicals, Inc.)

Retinal and optic nerve diseases are degenerative ocular pathologies which lead to irreversible visual loss. Since the advanced therapies availability, cell-based therapies offer a new all-encompassing approach. Advances in the knowledge of neuroprotection, immunomodulation and regenerative properties of mesenchymal stem cells (MSCs) have been obtained by several preclinical studies of various neurodegenerative diseases. It has provided the opportunity to perform the translation of this knowledge to prospective treatment approaches for clinical practice. Since 2008, several first steps projecting new treatment approaches, have been taken regarding the use of cell therapy in patients with neurodegenerative pathologies of optic nerve and retina. Most of the clinical trials using MSCs are in I/II phase, recruiting patients or ongoing, and they have as main objective the safety assessment of MSCs using various routes of administration. However, it is important to recognize that, there is still a long way to go to reach clinical trials phase III-IV. Hence, it is necessary to continue preclinical and clinical studies to improve this new therapeutic tool. This paper reviews the latest progress of MSCs in human clinical trials for retinal and optic nerve diseases., Competing Interests: Conflict-of-interest statement: The authors have no conflicts of interest to disclose.

Aims: Tobacco-related cancers and, in particular, lung cancer still represents a substantial public health epidemic across Europe as a result of high rates of smoking prevalence. Countries in Europe have proposed and implemented tobacco control policies to reduce smoking prevalence, with some countries being more progressive than others. The aim of this study was to examine factors that influenced women's attitudes across five European countries relative to comprehensive smokefree laws in their countries., Methods: A cross-sectional landline telephone survey on attitudes towards tobacco control laws was conducted in five European countries: France, Ireland, Italy, the Czech Republic, and Sweden. Attitudinal scores were determined for each respondent relative to questions about smokefree laws. Logistic regression models were used to obtain odds ratios with 95% confidence intervals., Results: A total of 5000 women were interviewed (1000 women from each country). The majority of women, regardless of smoking history, objected to smoking in public buses, enclosed shopping centers, hospitals, and other indoor work places. More women who had quit smoking believed that new tobacco control laws would prompt cessation - as compared with women who still smoked., Conclusions: In general, there is very high support for national smokefree laws that cover bars, restaurants, and public transport systems. As such laws are implemented, attitudes do change, as demonstrated by the differences between countries such as Ireland and the Czech Republic. Implementing comprehensive smokefree laws will gain high approval and will be associated with prompting people to quit.

Background: Lung cancer mortality in women is increasing across Europe, reflecting the alarming increase in smoking prevalence. Understanding women's perception of smoking may help to identify ways to reduce its prevalence and prevent uptake of smoking. The aim of this study was to examine factors associated with knowledge and beliefs about smoking and cancer among European women., Methods: A cross-sectional landline telephone survey on health attitudes and knowledge was conducted in five European countries: France, Ireland, Italy, the Czech Republic, and Sweden. A general linear modeling was used to explore the factors related to knowledge and beliefs about smoking and cancer., Results: A total of 5,000 women were interviewed (1,000 women from each country). The mean knowledge and belief scores about smoking and cancer were lower in current smokers than those of never and former smokers (P < 0.05). Women with above-the-median income (P = 0.001) and women who held skilled occupations seemed to be more knowledgeable about tobacco health risks (P < 0.001). The number of friends and family who smoked was inversely associated with knowledge on the harmful effects of tobacco (P = 0.001). Swedish women were the most knowledgeable about tobacco-related cancer risk, whereas in France and Italy, current smokers were less knowledgeable., Conclusions: Knowledge and beliefs about cancer and smoking varied significantly by smoking status., Impact: Results emphasize the need to develop health education programs that enhance cancer knowledge among women who currently smoke and are in low socioeconomic groups., (©2010 AACR.)

The explanation of Mendelian inheritance is a key component of most genetic counselling consultations, yet no evidence base exists for this area of practice. This qualitative study used Interpersonal Process Recall (IPR) to explore how information about X-linked inheritance is provided and received in genetic counseling. Twelve consultations involving two senior genetic counselors and 21 counselees were videotaped. Section(s) of videotape featuring the explanation were subsequently played back separately to both counselees and counselors and their responses and reflections recorded. All interviews were fully transcribed and analysed using the constant comparison method. A personalized diagram, drawn "live" by the counselor during the consultation was recalled by counselees as being central to their understanding of the "bottom line". This helped bridge the gap between scientific information and their family experience and did not appear to require a baseline understanding of genetic concepts such as genes or chromosomes. Counselors reflected on the diagram's positive impact on the way they sequenced, paced and tailored the explanation. A positive counselor-counselee relationship was vital even during this educative exchange: for counselees to feel at ease discussing complex genetic information and to help gauge counselee understanding.

Vascular pathology is frequently found in the brains of patients with Alzheimer's disease (AD). The aim of this study is to assess the frequency of vascular pathology in the brain in AD patients in a systematic manner and its clinical significance at presentation. A series of 51 patients with mild to moderate AD were consecutively enrolled. At baseline, every patient underwent the following clinical scales: Mini-Mental, Clinical Dementia Rating Scale, Ischemic Scale, Blessed Dementia Rating Scale, Alzheimer's Disease Assessment Scale Cognitive Subscale, Neuropsychiatric Inventory, and an Activities of Daily Living Scale (Disability Assessment for Dementia). We also carried out magnetic resonance imaging of the brain and color echo Doppler of carotids to measure the intima-media thickness. White matter hyperintensities were quantitatively evaluated with the Wahlund scale. We did not find correlation between intima-media thicknesses of carotids and clinical scales and between the Wahlund scale and clinical scales. The presence or absence of both microinfarctions and hypertension had no influence in the scores of the clinical scales. We conclude that the vascular component is common in AD but only as coincident pathology.

Organs are made up of cells from separate origins, whose development and differentiation must be integrated to produce a physiologically coherent structure. For example, during the development of the kidney, a series of interactions between the epithelial mesonephric duct and the surrounding metanephric mesenchyme leads to the formation of renal tubules. Cells of the metanephric mesenchyme first induce branching of the mesonephric duct to form the ureteric buds, and they then respond to signals derived from them. As a result, mesenchymal cells are recruited to the buds, where they undergo a mesenchymal-to-epithelial transition as they condense to form nephrons. In contrast, the simple renal tubules of invertebrates, such as insect Malpighian tubules (MpTs), have always been thought to arise from single tissue primordia, epithelial buds that grow by cell division and enlargement and from which a range of specialized subtypes differentiate. Here, we reveal unexpected parallels between the development of Drosophila MpTs and vertebrate nephrogenesis by showing that the MpTs also derive from two cell populations: ectodermal epithelial buds and the surrounding mesenchymal mesoderm. The mesenchymal cells are recruited to the growing tubules, where they undergo a mesenchymal-to-epithelial transition as they integrate and subsequently differentiate as a physiologically distinctive subset of tubule cells, the stellate cells. Strikingly, the normal incorporation of stellate cells and the later physiological activity of the mature tubules depend on the activity of hibris, an ortholog of mammalian NEPHRIN.

Cell proliferation in the developing renal tubules of Drosophila is strikingly patterned, occurring in two phases to generate a consistent number of tubule cells. The later phase of cell division is promoted by EGF receptor signalling from a specialised subset of tubule cells, the tip cells, which express the protease Rhomboid and are thus able to secrete the EGF ligand, Spitz. We show that the response to EGF signalling, and in consequence cell division, is patterned by the specification of a second cell type in the tubules. These cells are primed to respond to EGF signalling by the transcription of two pathway effectors, PointedP2, which is phosphorylated on pathway activation, and Seven up. While expression of pointedP2 is induced by Wingless signalling, seven up is initiated in a subset of the PointedP2 cells through the activity of the proneural genes. We demonstrate that both signalling and responsive cells are set aside in each tubule primordium from a proneural gene-expressing cluster of cells, in a two-step process. First, a proneural cluster develops within the domain of Wingless-activated, pointedP2-expressing cells to initiate the co-expression of seven up. Second, lateral inhibition, mediated by the neurogenic genes, acts within this cluster of cells to segregate the tip cell precursor, in which proneural gene expression strengthens to initiate rhomboid expression. As a consequence, when the precursor cell divides, both daughters secrete Spitz and become signalling cells. Establishing domains of cells competent to transduce the EGF signal and divide ensures a rapid and reliable response to mitogenic signalling in the tubules and also imposes a limit on the extent of cell division, thus preventing tubule hyperplasia.