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In this work, the mechanical response oF an one-dimensional active solid -- defined as a network of active stochastic particles interacting by nonlinear hard springs -- subject to an external deformation force, is numerically studied and rationalized with a minimal model. It is found that an active solid made of linear springs and subject to an external stress, presents an average deformation which is independent of the system's activity. However, when the active solid is made of nonlinear hard springs, the solid's average deformation decreases with respect to a passive system under the same conditions, and as a function of activity and rotational noise in the system. The latter result may shed light on new ways to creating an active metamaterial, which could tune its stiffness by moving either its activity or rotational noise.

El presente artículo presenta un conjunto de ideas teóricas orientadas a explicar y resolver la crisis política chilena actual; cada una de esas ideas está fundamentada con datos empíricos de la situación nacional. Al final del artículo, y sobre la base de este análisis, se presentan algunas líneas y propuestas de salida que tienen como objetivos reflexionar serenamente respecto de las soluciones posibles a la profunda crisis nacional.

This study evaluated the feasibility and efficacy of voluntary sustained hyperventilation during rapid ascent to high altitude for the prevention of acute mountain sickness (AMS). Study subjects (n=32) were volunteer participants in a 2-day expedition to Mount Leoneras (4954 m), starting at 2800m (base camp at 4120 m). Subjects were randomized to either: 1) an intervention group using the voluntary hyperventilation (VH) technique targeting an end-tidal CO2 (ETCO2)

In this paper, we present modified homotopy perturbation method coupled by Laplace transform to solve non-linear problems. As case study modified homotopy perturbation method coupled by Laplace transform is employed in order to obtain an approximate solution for the non-linear differential equation that describes the steady-state of a heat 1-D flow. The comparison between approximate and exact solutions shows the practical potentiality of the method.

Background First-line pembrolizumab monotherapy improves overall and progression-free survival in patients with untreated metastatic non-small-cell lung cancer with a programmed death ligand 1 (PD-L1) tumour proportion score (TPS) of 50% or greater. We investigated overall survival after treatment with pembrolizumab monotherapy in patients with a PD-L1 TPS of 1% or greater. Methods This randomised, open-label, phase 3 study was done in 213 medical centres in 32 countries. Eligible patients were adults (≥18 years) with previously untreated locally advanced or metastatic non-small-cell lung cancer without a sensitising EGFR mutation or ALK translocation and with an Eastern Cooperative Oncology Group (ECOG) performance status score of 0 or 1, life expectancy 3 months or longer, and a PD-L1 TPS of 1% or greater. Randomisation was computer generated, accessed via an interactive voice-response and integrated web-response system, and stratified by region of enrolment (east Asia vs rest of world), ECOG performance status score (0 vs 1), histology (squamous vs non-squamous), and PD-L1 TPS (≥50% vs 1-49%). Enrolled patients were randomly assigned 1:1 in blocks of four per stratum to receive pembrolizumab 200 mg every 3 weeks for up to 35 cycles or the investigator's choice of platinum-based chemotherapy for four to six cycles. Primary endpoints were overall survival in patients with a TPS of 50% or greater, 20% or greater, and 1% or greater (one-sided significance thresholds, p=0·0122, p=0·0120, and p=0·0124, respectively) in the intention-to-treat population, assessed sequentially if the previous findings were significant. This study is registered at ClinicalTrials.gov, number NCT02220894. Findings From Dec 19, 2014, to March 6, 2017, 1274 patients (902 men, 372 women, median age 63 years [IQR 57-69]) with a PD-L1 TPS of 1% or greater were allocated to pembrolizumab (n=637) or chemotherapy (n=637) and included in the intention-to-treat population. 599 (47%) had a TPS of 50% or greater and 818 patients (64%) had a TPS of 20% or greater. As of Feb 26, 2018, median follow-up was 12·8 months. Overall survival was significantly longer in the pembrolizumab group than in the chemotherapy group in all three TPS populations (≥50% hazard ratio 0·69, 95% CI 0·56-0·85, p=0·0003; ≥20% 0·77, 0·64-0·92, p=0·0020, and ≥1% 0·81, 0·71-0·93, p=0·0018). The median surival values by TPS population were 20·0 months (95% CI 15·4-24·9) for pembrolizumab versus 12·2 months (10·4-14·2) for chemotherapy, 17·7 months (15·3-22·1) versus 13·0 months (11·6-15·3), and 16·7 months (13·9-19·7) versus 12·1 months (11·3-13·3), respectively. Treatment-related adverse events of grade 3 or worse occurred in 113 (18%) of 636 treated patients in the pembrolizumab group and in 252 (41%) of 615 in the chemotherapy group and led to death in 13 (2%) and 14 (2%) patients, respectively. Interpretation The benefit-to-risk profile suggests that pembrolizumab monotherapy can be extended as first-line therapy to patients with locally advanced or metastatic non-small-cell lung cancer without sensitising EGFR or ALK alterations and with low PD-L1 TPS. Funding Merck Sharp & Dohme.

Significance Genome reduction is commonly observed in bacteria of several phyla engaging in obligate nutritional symbioses with insects. In Actinobacteria, however, little is known about the process of genome evolution, despite their importance as prolific producers of antibiotics and their increasingly recognized role as defensive partners of insects and other organisms. Here, we show that “Streptomyces philanthi,” a defensive symbiont of digger wasps, has a G+C-enriched genome in the early stages of erosion, with inactivating mutations in a large proportion of genes, causing dependency on its hosts for certain nutrients, which was validated in axenic symbiont cultures. Additionally, overexpressed catabolic and biosynthetic pathways of the bacteria inside the host indicate host–symbiont metabolic integration for streamlining and control of antibiotic production., Genome erosion is a frequently observed result of relaxed selection in insect nutritional symbionts, but it has rarely been studied in defensive mutualisms. Solitary beewolf wasps harbor an actinobacterial symbiont of the genus Streptomyces that provides protection to the developing offspring against pathogenic microorganisms. Here, we characterized the genomic architecture and functional gene content of this culturable symbiont using genomics, transcriptomics, and proteomics in combination with in vitro assays. Despite retaining a large linear chromosome (7.3 Mb), the wasp symbiont accumulated frameshift mutations in more than a third of its protein-coding genes, indicative of incipient genome erosion. Although many of the frameshifted genes were still expressed, the encoded proteins were not detected, indicating post-transcriptional regulation. Most pseudogenization events affected accessory genes, regulators, and transporters, but “Streptomyces philanthi” also experienced mutations in central metabolic pathways, resulting in auxotrophies for biotin, proline, and arginine that were confirmed experimentally in axenic culture. In contrast to the strong A+T bias in the genomes of most obligate symbionts, we observed a significant G+C enrichment in regions likely experiencing reduced selection. Differential expression analyses revealed that—compared to in vitro symbiont cultures—“S. philanthi” in beewolf antennae showed overexpression of genes for antibiotic biosynthesis, the uptake of host-provided nutrients and the metabolism of building blocks required for antibiotic production. Our results show unusual traits in the early stage of genome erosion in a defensive symbiont and suggest tight integration of host–symbiont metabolic pathways that effectively grants the host control over the antimicrobial activity of its bacterial partner.

We theoretically and computationally find a Maxwell-Boltzmann-like velocity distribution for noninteracting active matter (NAM). To achieve this, mass and moment of inertia are incorporated into the corresponding noninteracting active Fokker-Planck equation (NAFP), thus solving for the first time, the underdamped scenario of NAM following a Fokker-Planck formalism. This time, the distribution results in a bimodal symmetric expression that contains the effect of inertia on transport properties of NAM. The analytical distribution is further compared to experiments dealing with vibrobots. A generalization of the Brinkman hierarchy for NAFP is also provided and used for systematically solving the NAFP in position space. This work is an important step toward characterizing active matter using an equivalent nonequilibrium statistical mechanics.

In this work, the dynamics of inertial (mass and moment of inertia) active Brownian particles trapped in a harmonic well is studied. This scenario has seen success when characterizing soft passive and active overdamped matter. Motivated by the variety of applications of this system, we analytically find the effect of translational and rotational inertia on the mean-square displacement (MSD), mean-square speed (MSS), swim, Reynolds, and total pressures of a system of inertial active Brownian particles subject to a weak and a strong harmonic trap. Following a Langevin formalism, we explicitly find that as inertia grows, the systems' MSD and total pressure are enhanced, but its MSS and swim pressure decrease. The use of Langevin dynamics simulations enables us to observe that as inertia grows, inertial active matter under a strong trap no longer "condensates" at the "border" of the trap, but it rather tends to uniformly spread in space. Our analytical results are also numerically validated.

It has been discovered that active matter generates novel physical quantities such as the swim pressure. This quantity arises from the exchange of extra momentum between active particles and the boundaries of the system. Given its origin, this quantity can exist at different scales; hence microorganisms and larger organisms like fish or birds generate their own swim pressure. For larger organisms or for high swimming speeds, inertia cannot necessarily be neglected; hence in this paper, we start by calculating analytically the effect of finite translational and rotational particles' inertia on the diffusion of a system of noninteracting spherical active Brownian particles. From this analysis, an enhanced diffusion coefficient due to rotational inertia is obtained, and an alternative effective persistence length and an alternative reorientation time, both sensitive to rotational inertia, are also identified. Afterwards, and to see the implications of finite inertia on bulk properties, the pressure of this system is elucidated by calculating its respective swim and Reynolds pressures. It is found that their sum becomes asymptotically sensitive to the square root of its rotational inertia. To validate our analytical results, Langevin dynamics simulations are also performed showing an excellent agreement between our theoretical predictions and the numerical results.

Summary Background Patients with advanced gastric or gastro-oesophageal junction cancer that progresses on chemotherapy have poor outcomes. We compared pembrolizumab with paclitaxel in patients with advanced gastric or gastro-oesophageal junction cancer that progressed on first-line chemotherapy with a platinum and fluoropyrimidine. Methods This randomised, open-label, phase 3 study was done at 148 medical centres in 30 countries. Eligible patients were randomised (1:1) in blocks of four per stratum with an interactive voice-response and integrated web-response system to receive either pembrolizumab 200 mg every 3 weeks for up to 2 years or standard-dose paclitaxel. Primary endpoints were overall survival and progression-free survival in patients with a programmed cell death ligand 1 (PD-L1) combined positive score (CPS) of 1 or higher. Safety was assessed in all patients, irrespective of CPS. The significance threshold for overall survival was p=0·0135 (one-sided). This trial is registered at ClinicalTrials.gov, number NCT02370498. Findings Between June 4, 2015, and July 26, 2016, 592 patients were enrolled. Of the 395 patients who had a PD-L1 CPS of 1 or higher, 196 patients were assigned to receive pembrolizumab and 199 patients were assigned to receive paclitaxel. As of Oct 26, 2017, 326 patients in the population with CPS of 1 or higher had died (151 [77%] of 196 patients in the pembrolizumab group and 175 [88%] of 199 patients in the paclitaxel group). Median overall survival was 9·1 months (95% CI 6·2–10·7) with pembrolizumab and 8·3 months (7·6–9·0) with paclitaxel (hazard ratio [HR] 0·82, 95% CI 0·66–1·03; one-sided p=0·0421). Median progression-free survival was 1·5 months (95% CI 1·4–2·0) with pembrolizumab and 4·1 months (3·1–4·2) with paclitaxel (HR 1·27, 95% CI 1·03–1·57). In the total population, grade 3–5 treatment-related adverse events occurred in 42 (14%) of the 294 patients treated with pembrolizumab and 96 (35%) of the 276 patients treated with paclitaxel. Interpretation Pembrolizumab did not significantly improve overall survival compared with paclitaxel as second-line therapy for advanced gastric or gastro-oesophageal junction cancer with PD-L1 CPS of 1 or higher. Pembrolizumab had a better safety profile than paclitaxel. Additional trials of pembrolizumab in gastric and gastro-oesophageal cancer are ongoing. Funding Merck Sharp & Dohme, a subsidiary of Merck & Co.

We formulate the dynamics of overdamped Brownian active particles (swimmers) moving on any Riemannian 2-manifold. To characterize such dynamics at short times, an analytical expression for the variance of swimmers diffusing on any Riemmanian 2-manifold is derived. To show the generality of the present work, we apply the latter dynamics to swimmers moving on the surface of a spheroid and a torus, and offer analytical expressions for both their long-time variances and steady angular marginal probability density functions. Finally, Brownian dynamics simulations are used to validate our theoretical findings.

Bacteria belonging to the genus Streptomyces are among the most prolific producers of antibiotics. Research on cellular membrane biosynthesis and turnover is lagging behind in Streptomyces compared to related organisms like Mycobacterium tuberculosis. While natural products discovery in Streptomyces is evidently a priority in order to discover new antibiotics to combat the increase in antibiotic resistant pathogens, a better understanding of this cellular compartment should provide insights into the interplay between core and secondary metabolism. However, some of the pathways for membrane lipid biosynthesis are still incomplete. In addition, while it has become clear that remodelling of the membrane is necessary for coping with environmental stress and for morphological differentiation, the detailed mechanisms of these adaptations remain elusive. Here, we aim to provide a summary of what is known about the polar lipid composition in Streptomyces, the biosynthetic pathways of polar lipids, and to highlight current gaps in understanding function, dynamics and biosynthesis of these essential molecules.

El presente artículo aborda el fenómeno de la violencia escolar desde la perspectiva de la teoría del riesgo en un contexto de profundo proceso de cambio cultural. Se trata de comprender el fenómeno de la violencia en los jóvenes desde una determinada perspectiva teórica, en un contexto determinado.Palabras clave Juventud /violencia / riesgo / escuela / educaciónThe present article approaches the phenomenon of students’ violence from the perspective of the risk theory in a context of deep process of cultural change. The matter is to understand the phenomenon of violence in the young people from a determined theoretical perspective, in a certain context.Key words Youth / violence / risk / school / education

ResumenEn términos amplios, nuestra reflexión se ubica en el contexto de las transformaciones sociales, económicas, políticas y culturales que viven las sociedades contemporáneas. Estas transformaciones se han perfilado como uno de los principales fenómenos en el inicio del Siglo XXI y han sido conceptualizadas de diversos modos: “sociedad de la información”, “sociedad del riesgo”, “sociedades postindustriales”, “sociedad sitiada”, entre otras nominaciones relevantes acuñadas por diversos autores. Estas expresiones manifiestan, de una u otra forma, que el cambio se ha constituido en una categoría central para el análisis de la experiencia personal y la organización de la sociedad actual.Palabras clave: Cultura escolar, cambio cultural, jóvenes, sociedad.AbstractIn broad terms, our reflection is to be found in the context of the social economic, political and cultural transformations that the contemporary societies live. These transformations have been outlined as one of the main phenomena in the beginning of XXI Century, and has been conceptualized in diverse ways: “society of the information”, “risk society”, “postindustrial societies”, “siege society”, among other outstanding expressions coined by diverse authors. These expressions declare in one way or another that the change has constituted in a central category for the analysis of the personal experience and the organization of the present society.Key words: Scholastic culture, cultural change, young people, society.

espanolLa movilizacion que las y los jovenes estudiantes –secundarios y despues universitarios– han venido desplegando en los ultimos 10 anos en el pais (PNUD 2015) ha gatillado un conjunto de cuestionamientos a la estructura social y la desigualdad en ella contenida. Esto ha llevado a que diversos sectores –mundo politico, opinion publica y otros- asuman esos planteamientos que organizan en buena medida la conversacion social en Chile. Acceder a la educacion superior es una sentida aspiracion de las actuales generaciones de jovenes que concluyen su ensenanza secundaria. Sin embargo, esta transicion es experimentada como un conjunto de tensiones –desajuste, desacomodo y malestar– que caracterizan el modo en que enfrentan y resuelven el paso de salir de cuarto medio. Dichas experiencias son una buena evidencia del tipo de sociedad chilena que se ha construido, y sus jovenes, otra vez, una buena metafora de la epoca actual. EnglishThe mobilization of young students –from secondary schools and later from higher education– over the past 10 years in the country (PNUD 2015) triggered a series of challenges to the social structure and its inequalities. These demands have led actors from the political space and public opinion, among others, to take up these approaches that are organizing social conversation in Chile. The access to higher education is an aspiration for the young who are finishing their secondary education. However, this transition is experienced as a mix of tensions –imbalance, dislocation and uneasiness– which characterize the way they face and solve the transition to graduate from secondary education. Such experiences illustrate the kind of society Chilean people have built, the young, once more, being a good metaphor for the present time.

We apply the homotopy analysis method to the motion of noninteracting active Brownian particles (ABPs) under a general situation such as in the presence of external fields, external torques, or even moving on non-Euclidean geometries. Within this framework, a general expression as a series solution in time for the probability density function (PDF) satisfying the Fokker-Planck (FP) equation is elucidated. Using the latter PDF, their respective mean values (first and second moments) are also found in general. Applications of the present technique are offered by solving classic ABP situations, namely free noninteracting ABPs, ABPs under a Poiseuille flow, and even ABPs confined to move on any Riemannian manifold. To improve the convergence of the obtained series solution for each situation, Pad\'e approximants are incorporated. It is worth mentioning that the offered methodology may exactly be applied to other fields such as chemistry, biology, or econophysics where a FP equation governs the system.

We characterise the diffusion, mean-square speed, mean-square angular displacement, radial and speed probability distributions of toy robots called ‘hexbugs-nano’ that move on a dish antenna (with added surface roughness) simulating a harmonic well. It is observed that a model considering the system’s translational inertia but neglecting its moment of inertia, together with the inclusion of a constant external torque in the orientational motion, suffices to describe the robots’ dynamics. Langevin dynamics simulation are also performed and a good agreement between theory, simulations and experiments is observed.

This paper aims at presenting the attempts to improve quality education in Chile characterized by the willingness of involved participants in the educational system. All participants agree to create mechanisms which permit to carry out effective strategies to offer real opportunities of improvement and equity. In this sense, it is necessary to highlight the historical agreement among the Ministry of Education, the Association of Municipalities and the Teachers' Association about the Assessment of Teachers' Performance. The objective of this assessment is to improve Teachers' Performance by means of designing and implementing a system of Professional Development Plans based on deficient results found in the assessment itself.

La problemática que se aborda en el presente artículo tiene su origen en la exigencia que se hace a la educación en general, y a la educación superior en particular, a modificar sus currículos y orientarlos por parámetros que en gran medida responden a necesidades de la economía. La tendencia actual es exigirle a la educación que produzca profesionales de alto nivel técnico, flexibles e innovadores, que sean capaces de actuar eficaz y eficientemente en situaciones nuevas, además de otras capacidades y habilidades que le permitan a la empresa ser competitiva. Nos preguntamos entonces si estamos ante una nueva forma de educar.

BACKGROUND The incidence of surgical complications after kidney transplantation ranges from 10-25%. The purpose of this study was to evaluate if the application of fibrin glue as a preventive agent reduces surgical morbidity after a living-related-donor kidney transplantation. MATERIAL AND METHODS A controlled clinical trial involving 78 recipients randomly assigned to receive fibrin glue and 79 in the control group without the application of fibrin glue. Patients were followed for six months after surgery. RESULTS The average ages were 24.8±9.4 and 27.4±11.3 years in the control and study groups, respectively (p=0.11). Individual morbidities, such as urologic, lymphatic, vascular, and wound complications, were not statistically different between groups; however, the total number of surgical complications observed were in five patients in the study group and 16 patients in the control group. This difference was statistically significant (p

International audience; The potential of the diverse chemistries present in natural products (NP) for biotechnology and medicine remains untapped because NP databases are not searchable with raw data and the NP community has no way to share data other than in published papers. Although mass spectrometry (MS) techniques are well-suited to high-throughput characterization of NP, there is a pressing need for an infrastructure to enable sharing and curation of data. We present Global Natural Products Social Molecular Networking (GNPS; http://gnps.ucsd.edu), an open-access knowledge base for community-wide organization and sharing of raw, processed or identified tandem mass (MS/MS) spectrometry data. In GNPS, crowdsourced curation of freely available community-wide reference MS libraries will underpin improved annotations. Data-driven social-networking should facilitate identification of spectra and foster collaborations. We also introduce the concept of 'living data' through continuous reanalysis of deposited data.

Background Early steroid withdrawal (ESW) can improve lipid and hemodynamic profiles without severe acute rejection (AR) events in renal transplant patients. Our objective was to evaluate the effects of ESW on the frequency and severity of AR. Methods A randomized, open-label, controlled clinical trial was performed on renal transplant recipients with a follow-up of 12 months. In the ESW group, patients were selected for corticosteroid treatment withdrawal on the fifth day post transplantation. In the Control group, patients continued with steroid treatment. All patients were over 18 years of age with panel reactive antibody (PRA) class I and II HLA Results In total, 71 patients, 37 in the ESW group (52.1%) and 34 in the Control group (47.9%), had comparable AR incidences at the end of the follow-up (16% vs 15%) (NS) (RR = 1.20, 95% CI = 0.32–3.33). Although renal graft survival was similar between the ESW and Control groups (87% vs 94%), renal function was superior in the ESW group (85 vs 75 mL/min). Additionally, hypertension was less frequent in the ESW group (3% vs 35%), requiring the use of fewer antihypertensives (8% vs 50%). Conclusions ESW was also associated with better blood pressure control and similar AR risk. The ESW group exhibited stable renal function.

We calculate the effective diffusion of a spherical self-propelled charged particle swimming at low Reynolds number, and subject to a time-dependent magnetic field and thermal agitation. We find that the presence of an external magnetic field may reduce or enhance (depending on the type of swimming and magnetic field applied) the swimmer’s effective diffusion, hence we get another possible strategy to control its displacement. For swimmers performing reciprocal motion, and under an oscillating time-dependent magnetic field, mechanical resonance appears when the swimmer and magnetic frequencies coincide, thus enhancing the particle’s effective diffusion. Our analytical results are compared with Brownian Dynamics simulations and we obtain excellent agreement.

We analytically find the diffusion of overdamped active Brownian particles (ABPs) constrained to move along curved one-dimensional channels. The autonomous motion of these particles is achieved by ...

A natural feature of a flock of birds is to develop time-dependent coherent patterns that spontaneously emerge during their flight. The origins and quantification of this phenomenon have been less studied. Here, we computationally show that this state can be reproduced by employing canonic interaction rules (radial and topological) together with a simple frustration rule; and characterize it introducing global and local order parameters. Using these parameters, we prove that both canonic interactions are able to generate this state; although it is observed that a topological interaction rule is more effective in reproducing it. Extra information is obtained after uncovering their respective interaction networks in time. In particular, the network efficiency measure in time for radial and topological rules is found and used to show that networks following topological interactions are more efficient through time. The presented analysis is general and can be used to quantify emergent phenomena in other groups of animals like fish, insects, ants or even humans performing collective motion.

We present analytical expressions for the mean-square displacement of self-driven particles in general linear flows and trapped in a harmonic potential. The general expressions are applied to three types of linear flows, namely, shear flow, solid-body rotation flow, and extensional flow. By using Brownian dynamics simulations, the effect of trapping and external linear flows on the particles' distribution is also elucidated. These simulations also enabled us to validate our theoretical results.

The idea of emergence originates from the fact that global effects emerge from local interactions producing a collective coherent behavior. A particular instance of emergence is illustrated by a flocking model of interacting “boids” encompassing two antagonistic conducts—consensus and frustration—giving rise to highly complex, unpredictable, coherent behavior. The cohesive motion arising from consensus can be described in terms of three ordered dynamic phases. Once frustration is included in the model, local phases for specific groups of flockmates, and transitions among them, replace the global ordered phases. Following the evolution of boids in a single group, we discovered that the boids in this group will alternate among the three phases. When we compare two uncorrelated groups, the second group shows a similar behavior to the first one, but with a different sequence of phases. Besides the visual observation of our animations with marked boids, the result is evident plotting the local order parameters. Rather than adopting one of the consensus ordered phases, the flock motion resembles more an entangled dynamic sequence of phase transitions involving each group of flockmates. © 2015 Wiley Periodicals, Inc. Complexity, 2015

Ornithine lipids (OLs) are phosphorus-free membrane lipids widespread in bacteria but absent from archaea and eukaryotes. In addition to the unmodified OLs, a variety of OL derivatives hydroxylated in different structural positions has been reported. Recently, methylated derivatives of OLs were described in several planctomycetes isolated from a peat bog in Northern Russia, although the gene/enzyme responsible for the N-methylation of OL remained obscure. Here we identify and characterize the OL N-methyltransferase OlsG (Sinac_1600) from the planctomycete Singulisphaera acidiphila. When OlsG is co-expressed with the OL synthase OlsF in Escherichia coli, methylated OL derivatives are formed. An in vitro characterization shows that OlsG is responsible for the 3-fold methylation of the terminal δ-nitrogen of OL. Methylation is dependent on the presence of the detergent Triton X-100 and the methyldonor S-adenosylmethionine.

Summary Phospholipids are well known for their membrane-forming properties and thereby delimit any cell from the exterior world. In addition, membrane phospholipids can act as precursors for signals and other biomolecules during their turnover. Little is known about phospholipid signalling, turnover and remodelling in bacteria. Recently, we showed that a FadD-deficient mutant of Sinorhizobium meliloti, unable to convert free fatty acids to their coenzyme A derivatives, accumulates free fatty acids during the stationary phase of growth. Enzymatic activities responsible for the generation of these free fatty acids were unknown in rhizobia. Searching the genome of S. meliloti, we identified a potential lysophospholipase (SMc04041) and two predicted patatin-like phospholipases A (SMc00930, SMc01003). Although SMc00930 as well as SMc01003 contribute to the release of free fatty acids in S. meliloti, neither one can use phospholipids as substrates. Here we show that SMc01003 converts diacylglycerol to monoacylglycerol and a fatty acid, and that monoacylglycerol can be further degraded by SMc01003 to another fatty acid and glycerol. A SMc01003-deficient mutant of S. meliloti transiently accumulates diacylglycerol, suggesting that SMc01003 also acts as diacylglycerol lipase (DglA) in its native background. Expression of the DglA lipase in Escherichia coli causes lysis of cells in stationary phase of growth.