Atomic force microscopy analysis of Pel polysaccharide- and type IV pili-mediated adhesion of Pseudomonas aeruginosa PA14 to an abiotic surface.

Type IV pili (TFP) contribute to the ability of microbes such as Pseudomonas aeruginosa to engage with and move across surfaces. We reported previously that P. aeruginosa TFP generate retractive forces of ∼30 pN and provided indirect evidence that TFP-mediated surface attachment was enhanced in the presence of the Pel polysaccharide. Here, we use different mutants defective in flagellar, Pel production or TFP production - alone or in combination - to decipher the relative contribution of these biofilm-promoting factors for P. aeruginosa adhesion. By means of atomic force microscopy (AFM), we show that mutating the flagellum (ΔflgK mutant) results in an increase in Pel polysaccharide production, but this increase in Pel does not result in an increase in surface adhesive properties compared to those previously described for the WT strain. By blocking Pel production in the ΔflgK mutant (ΔflgKΔpel), we directly show that TFP play a major role in the adhesion of the bacteria to hydrophobic AFM tips, but that the adhesion force is only slightly impaired by the absence of Pel. Inversely, performing single-cell force spectroscopy measurements with the mutant lacking TFP (ΔflgKΔpilA) reveals that the Pel can modulate the attachment of the bacteria to a hydrophobic substrate in a time-dependent manner. Finally, little adhesion was detected for the ΔflgKΔpilAΔpelA triple mutant, suggesting that both TFP and Pel polysaccharide make a substantial contribution to bacteria-substratum interaction events. Altogether, our data allow us to decipher the relative contribution of Pel and TFP in the early attachment by P. aeruginosa.

Porous marine snow differentially benefits chemotactic, motile, and nonmotile bacteria.

Particulate organic carbon settling through the marine water column is a key process that regulates the global climate by sequestering atmospheric carbon. The initial colonization of marine particles by heterotrophic bacteria represents the first step in recycling this carbon back to inorganic constituents-setting the magnitude of vertical carbon transport to the abyss. Here, we demonstrate experimentally using millifluidic devices that, although bacterial motility is essential for effective colonization of a particle leaking organic nutrients into the water column, chemotaxis specifically benefits at intermediate and higher settling velocities to navigate the particle boundary layer during the brief window of opportunity provided by a passing particle. We develop an individual-based model that simulates the encounter and attachment of bacterial cells with leaking marine particles to systematically evaluate the role of different parameters associated with bacterial run-and-tumble motility. We further use this model to explore the role of particle microstructure on the colonization efficiency of bacteria with different motility traits. We find that the porous microstructure facilitates additional colonization by chemotactic and motile bacteria, and fundamentally alters the way nonmotile cells interact with particles due to streamlines intersecting with the particle surface.

Social Cooperativity of Bacteria during Reversible Surface Attachment in Young Biofilms: a Quantitative Comparison of Pseudomonas aeruginosa PA14 and PAO1.

What are bacteria doing during "reversible attachment," the period of transient surface attachment when they initially engage a surface, besides attaching themselves to the surface? Can an attaching cell help any other cell attach? If so, does it help all cells or employ a more selective strategy to help either nearby cells (spatial neighbors) or its progeny (temporal neighbors)? Using community tracking methods at the single-cell resolution, we suggest answers to these questions based on how reversible attachment progresses during surface sensing for Pseudomonas aeruginosa strains PAO1 and PA14. Although PAO1 and PA14 exhibit similar trends of surface cell population increase, they show unanticipated differences when cells are considered at the lineage level and interpreted using the quantitative framework of an exactly solvable stochastic model. Reversible attachment comprises two regimes of behavior, processive and nonprocessive, corresponding to whether cells of the lineage stay on the surface long enough to divide, or not, before detaching. Stark differences between PAO1 and PA14 in the processive regime of reversible attachment suggest the existence of two surface colonization strategies. PAO1 lineages commit quickly to a surface compared to PA14 lineages, with early c-di-GMP-mediated exopolysaccharide (EPS) production that can facilitate the attachment of neighbors. PA14 lineages modulate their motility via cyclic AMP (cAMP) and retain memory of the surface so that their progeny are primed for improved subsequent surface attachment. Based on the findings of previous studies, we propose that the differences between PAO1 and PA14 are potentially rooted in downstream differences between Wsp-based and Pil-Chp-based surface-sensing systems, respectively.IMPORTANCE The initial pivotal phase of bacterial biofilm formation known as reversible attachment, where cells undergo a period of transient surface attachment, is at once universal and poorly understood. What is more, although we know that reversible attachment culminates ultimately in irreversible attachment, it is not clear how reversible attachment progresses phenotypically, as bacterial surface-sensing circuits fundamentally alter cellular behavior. We analyze diverse observed bacterial behavior one family at a time (defined as a full lineage of cells related to one another by division) using a unifying stochastic model and show that our findings lead to insights on the time evolution of reversible attachment and the social cooperative dimension of surface attachment in PAO1 and PA14 strains.

Ethanol Decreases Pseudomonas aeruginosa Flagellar Motility through the Regulation of Flagellar Stators.

Pseudomonas aeruginosa frequently encounters microbes that produce ethanol. Low concentrations of ethanol reduced P. aeruginosa swim zone area by up to 45% in soft agar. The reduction of swimming by ethanol required the flagellar motor proteins MotAB and two PilZ domain proteins (FlgZ and PilZ). PilY1 and the type 4 pilus alignment complex (comprising PilMNOP) were previously implicated in MotAB regulation in surface-associated cells and were required for ethanol-dependent motility repression. As FlgZ requires the second messenger bis-(3'-5')-cyclic dimeric GMP (c-di-GMP) to represses motility, we screened mutants lacking genes involved in c-di-GMP metabolism and found that mutants lacking diguanylate cyclases SadC and GcbA were less responsive to ethanol. The double mutant was resistant to its effects. As published previously, ethanol also represses swarming motility, and the same genes required for ethanol effects on swimming motility were required for its regulation of swarming. Microscopic analysis of single cells in soft agar revealed that ethanol effects on swim zone area correlated with ethanol effects on the portion of cells that paused or stopped during the time interval analyzed. Ethanol increased c-di-GMP in planktonic wild-type cells but not in ΔmotAB or ΔsadC ΔgcbA mutants, suggesting c-di-GMP plays a role in the response to ethanol in planktonic cells. We propose that ethanol produced by other microbes induces a regulated decrease in P. aeruginosa motility, thereby promoting P. aeruginosa colocalization with ethanol-producing microbes. Furthermore, some of the same factors involved in the response to surface contact are involved in the response to ethanol.IMPORTANCE Ethanol is an important biologically active molecule produced by many bacteria and fungi. It has also been identified as a potential marker for disease state in cystic fibrosis. In line with previous data showing that ethanol promotes biofilm formation by Pseudomonas aeruginosa, here we report that ethanol reduces swimming motility using some of the same proteins involved in surface sensing. We propose that these data may provide insight into how microbes, via their metabolic byproducts, can influence P. aeruginosa colocalization in the context of infection and in other polymicrobial settings.

Flagellar Stators Stimulate c-di-GMP Production by Pseudomonas aeruginosa.

Flagellar motility is critical for surface attachment and biofilm formation in many bacteria. A key regulator of flagellar motility in Pseudomonas aeruginosa and other microbes is cyclic diguanylate (c-di-GMP). High levels of this second messenger repress motility and stimulate biofilm formation. c-di-GMP levels regulate motility in P. aeruginosa in part by influencing the localization of its two flagellar stator sets, MotAB and MotCD. Here, we show that while c-di-GMP can influence stator localization, stators can in turn impact c-di-GMP levels. We demonstrate that the swarming motility-driving stator MotC physically interacts with the transmembrane region of the diguanylate cyclase SadC. Furthermore, we demonstrate that this interaction is capable of stimulating SadC activity. We propose a model by which the MotCD stator set interacts with SadC to stimulate c-di-GMP production under conditions not permissive to motility. This regulation implies a positive-feedback loop in which c-di-GMP signaling events cause MotCD stators to disengage from the motor; then disengaged stators stimulate c-di-GMP production to reinforce a biofilm mode of growth. Our studies help to define the bidirectional interactions between c-di-GMP and the flagellar machinery.IMPORTANCE The ability of bacterial cells to control motility during early steps in biofilm formation is critical for the transition to a nonmotile, biofilm lifestyle. Recent studies have clearly demonstrated the ability of c-di-GMP to control motility via a number of mechanisms, including through controlling transcription of motility-related genes and modulating motor function. Here, we provide evidence that motor components can in turn impact c-di-GMP levels. We propose that communication between motor components and the c-di-GMP synthesis machinery allows the cell to have a robust and sensitive switching mechanism to control motility during early events in biofilm formation.

Multigenerational memory and adaptive adhesion in early bacterial biofilm communities.

Using multigenerational, single-cell tracking we explore the earliest events of biofilm formation by Pseudomonas aeruginosa During initial stages of surface engagement (≤20 h), the surface cell population of this microbe comprises overwhelmingly cells that attach poorly (∼95% stay <30 s, well below the ∼1-h division time) with little increase in surface population. If we harvest cells previously exposed to a surface and direct them to a virgin surface, we find that these surface-exposed cells and their descendants attach strongly and then rapidly increase the surface cell population. This "adaptive," time-delayed adhesion requires determinants we showed previously are critical for surface sensing: type IV pili (TFP) and cAMP signaling via the Pil-Chp-TFP system. We show that these surface-adapted cells exhibit damped, coupled out-of-phase oscillations of intracellular cAMP levels and associated TFP activity that persist for multiple generations, whereas surface-naïve cells show uncorrelated cAMP and TFP activity. These correlated cAMP-TFP oscillations, which effectively impart intergenerational memory to cells in a lineage, can be understood in terms of a Turing stochastic model based on the Pil-Chp-TFP framework. Importantly, these cAMP-TFP oscillations create a state characterized by a suppression of TFP motility coordinated across entire lineages and lead to a drastic increase in the number of surface-associated cells with near-zero translational motion. The appearance of this surface-adapted state, which can serve to define the historical classification of "irreversibly attached" cells, correlates with family tree architectures that facilitate exponential increases in surface cell populations necessary for biofilm formation.

High-Speed "4D" Computational Microscopy of Bacterial Surface Motility.

Bacteria exhibit surface motility modes that play pivotal roles in early-stage biofilm community development, such as type IV pili-driven "twitching" motility and flagellum-driven "spinning" and "swarming" motility. Appendage-driven motility is controlled by molecular motors, and analysis of surface motility behavior is complicated by its inherently 3D nature, the speed of which is too fast for confocal microscopy to capture. Here, we combine electromagnetic field computation and statistical image analysis to generate 3D movies close to a surface at 5 ms time resolution using conventional inverted microscopes. We treat each bacterial cell as a spherocylindrical lens and use finite element modeling to solve Maxwell's equations and compute the diffracted light intensities associated with different angular orientations of the bacterium relative to the surface. By performing cross-correlation calculations between measured 2D microscopy images and a library of computed light intensities, we demonstrate that near-surface 3D movies of Pseudomonas aeruginosa translational and rotational motion are possible at high temporal resolution. Comparison between computational reconstructions and detailed hydrodynamic calculations reveals that P. aeruginosa act like low Reynolds number spinning tops with unstable orbits, driven by a flagellum motor with a torque output of ∼2 pN µm. Interestingly, our analysis reveals that P. aeruginosa can undergo complex flagellum-driven dynamical behavior, including precession, nutation, and an unexpected taxonomy of surface motility mechanisms, including upright-spinning bacteria that diffuse laterally across the surface, and horizontal bacteria that follow helicoidal trajectories and exhibit superdiffusive movements parallel to the surface.

Drosophila DNA polymerase theta utilizes both helicase-like and polymerase domains during microhomology-mediated end joining and interstrand crosslink repair.

Double strand breaks (DSBs) and interstrand crosslinks (ICLs) are toxic DNA lesions that can be repaired through multiple pathways, some of which involve shared proteins. One of these proteins, DNA Polymerase θ (Pol θ), coordinates a mutagenic DSB repair pathway named microhomology-mediated end joining (MMEJ) and is also a critical component for bypass or repair of ICLs in several organisms. Pol θ contains both polymerase and helicase-like domains that are tethered by an unstructured central region. While the role of the polymerase domain in promoting MMEJ has been studied extensively both in vitro and in vivo, a function for the helicase-like domain, which possesses DNA-dependent ATPase activity, remains unclear. Here, we utilize genetic and biochemical analyses to examine the roles of the helicase-like and polymerase domains of Drosophila Pol θ. We demonstrate an absolute requirement for both polymerase and ATPase activities during ICL repair in vivo. However, similar to mammalian systems, polymerase activity, but not ATPase activity, is required for ionizing radiation-induced DSB repair. Using a site-specific break repair assay, we show that overall end-joining efficiency is not affected in ATPase-dead mutants, but there is a significant decrease in templated insertion events. In vitro, Pol θ can efficiently bypass a model unhooked nitrogen mustard crosslink and promote DNA synthesis following microhomology annealing, although ATPase activity is not required for these functions. Together, our data illustrate the functional importance of the helicase-like domain of Pol θ and suggest that its tethering to the polymerase domain is important for its multiple functions in DNA repair and damage tolerance.

Bacteria, Rev Your Engines: Stator Dynamics Regulate Flagellar Motility.

Many bacteria move through liquids and across surfaces by using flagella-filaments propelled by a membrane-embedded rotary motor. Much is known about the flagellum: its basic structure, the function of its individual motor components, and the regulation of its synthesis. However, we are only beginning to identify the dynamics of flagellar proteins and to understand how the motor structurally adapts to environmental stimuli. In this review, we discuss the external and cellular factors that influence the dynamics of stator complexes (the ion-conducting channels of the flagellar motor). We focus on recent discoveries suggesting that stator dynamics are a means for controlling flagellar function in response to different environments.

Role of Cyclic Di-GMP and Exopolysaccharide in Type IV Pilus Dynamics.

For Pseudomonas aeruginosa, levels of cyclic di-GMP (c-di-GMP) govern the transition from the planktonic state to biofilm formation. Type IV pili (T4P) are crucial determinants of biofilm structure and dynamics, but it is unknown how levels of c-di-GMP affect pilus dynamics. Here, we scrutinized how c-di-GMP affects molecular motor properties and adhesive behavior of T4P. By means of retraction, T4P generated forces of ∼30 pN. Deletion mutants in the proteins with known roles in biofilm formation, swarming motility, and exopolysaccharide (EPS) production (specifically, the diguanylate cyclases sadC and roeA or the c-di-GMP phosphodiesterase bifA) showed only modest effects on velocity or force of T4P retraction. At high levels of c-di-GMP, the production of exopolysaccharides, particularly of Pel, is upregulated. We found that Pel production strongly enhances T4P-mediated surface adhesion of P. aeruginosa, suggesting that T4P-matrix interactions may be involved in biofilm formation by P. aeruginosa Finally, our data support the previously proposed model of slingshot-like "twitching" motility of P. aeruginosaIMPORTANCE Type IV pili (T4P) play various important roles in the transition of bacteria from the planktonic state to the biofilm state, including surface attachment and surface sensing. Here, we investigate adhesion, dynamics, and force generation of T4P after bacteria engage a surface. Our studies showed that two critical components of biofilm formation by Pseudomonas aeruginosa, T4P and exopolysaccharides, contribute to enhanced T4P-mediated force generation by attached bacteria. These data indicate a crucial role for the coordinated impact of multiple biofilm-promoting factors during the early stages of attachment to a surface. Our data are also consistent with a previous model explaining why pilus-mediated motility in P. aeruginosa results in characteristic "twitching" behavior.

PilZ Domain Protein FlgZ Mediates Cyclic Di-GMP-Dependent Swarming Motility Control in Pseudomonas aeruginosa.

UNLABELLED: The second messenger cyclic diguanylate (c-di-GMP) is an important regulator of motility in many bacterial species. In Pseudomonas aeruginosa, elevated levels of c-di-GMP promote biofilm formation and repress flagellum-driven swarming motility. The rotation of P. aeruginosa's polar flagellum is controlled by two distinct stator complexes, MotAB, which cannot support swarming motility, and MotCD, which promotes swarming motility. Here we show that when c-di-GMP levels are elevated, swarming motility is repressed by the PilZ domain-containing protein FlgZ and by Pel polysaccharide production. We demonstrate that FlgZ interacts specifically with the motility-promoting stator protein MotC in a c-di-GMP-dependent manner and that a functional green fluorescent protein (GFP)-FlgZ fusion protein shows significantly reduced polar localization in a strain lacking the MotCD stator. Our results establish FlgZ as a c-di-GMP receptor affecting swarming motility by P. aeruginosa and support a model wherein c-di-GMP-bound FlgZ impedes motility via its interaction with the MotCD stator. IMPORTANCE: The regulation of surface-associated motility plays an important role in bacterial surface colonization and biofilm formation. c-di-GMP signaling is a widespread means of controlling bacterial motility, and yet the mechanism whereby this signal controls surface-associated motility in P. aeruginosa remains poorly understood. Here we identify a PilZ domain-containing c-di-GMP effector protein that contributes to c-di-GMP-mediated repression of swarming motility by P. aeruginosa We provide evidence that this effector, FlgZ, impacts swarming motility via its interactions with flagellar stator protein MotC. Thus, we propose a new mechanism for c-di-GMP-mediated regulation of motility for a bacterium with two flagellar stator sets, increasing our understanding of surface-associated behaviors, a key prerequisite to identifying ways to control the formation of biofilm communities.

Engaging with culturally and linguistically diverse communities to reduce the impact of depression and anxiety: a narrative review.

Culturally and linguistically diverse (CALD) communities in Australia face significant challenges in terms of reducing barriers to information and support for depression and anxiety. Increased stigma surrounding mental ill-health in some cultures and related concerns about trust and confidentiality all impact upon timely access to information, services and support for consumers and carers from CALD backgrounds. For health services, there is a need to understand how to better engage CALD communities in mental healthcare. The objective of this narrative review was to identify examples of evidence-based, best practice for what works effectively for engaging with CALD communities to reduce the impact of depression and anxiety. In January 2014, we searched Academic Search Premier, CINAHL, Health-Source Consumer Edition, PsycARTICLES, PsycINFO (all databases within the EbscoHost platform) and PubMed for peer-reviewed articles published between 1994 and 2014. The search revealed a total of 706 records contained within the EbscoHost platform and 689 records in PubMed; 15 matched the inclusion criteria. Six key themes were identified: (i) setting the scene for engagement; (ii) cultural values and preferences; (iii) language considerations; (iv) 'engagers' in the therapeutic process; (v) opening out engagement to include others; and (vi) engaging through the use of technology and alternative mediums. The literature obtained provides a small body of evidence regarding approaches to engaging CALD communities, with findings highlighting the importance of processes which are tailored to the CALD community of interest and which take into account different cultural explanatory models of mental ill-health. Review findings are also discussed within the framework of intersectionality, in which broader structural inequalities and power imbalances - in areas such as gender and social class - collectively impact on help-seeking and mental health outcomes. This review supports further enquiry into how such societal issues influence engagement - and disengagement - in mental health services for CALD communities.

'You just lose the people you know': relationship loss and mental illness.

The purpose of this qualitative study was to explore the nature, scope and consequences of losses resulting from mental illness. This paper presents findings from a key theme of this study-the loss of relationships. Thematic analysis revealed two categories: loss of intimate relationships, which included subcategories of (i) spouses/partners, (ii) children/parenthood, (iii) family, and (iv) friends; and (2) people within the community, such as people at church and support groups. Relationships are seen as one of the most crucial yet challenging elements to recovery and wellbeing for people affected by mental illness.

A hierarchical cascade of second messengers regulates Pseudomonas aeruginosa surface behaviors.

UNLABELLED: Biofilms are surface-attached multicellular communities. Using single-cell tracking microscopy, we showed that a pilY1 mutant of Pseudomonas aeruginosa is defective in early biofilm formation. We leveraged the observation that PilY1 protein levels increase on a surface to perform a genetic screen to identify mutants altered in surface-grown expression of this protein. Based on our genetic studies, we found that soon after initiating surface growth, cyclic AMP (cAMP) levels increase, dependent on PilJ, a chemoreceptor-like protein of the Pil-Chp complex, and the type IV pilus (TFP). cAMP and its receptor protein Vfr, together with the FimS-AlgR two-component system (TCS), upregulate the expression of PilY1 upon surface growth. FimS and PilJ interact, suggesting a mechanism by which Pil-Chp can regulate FimS function. The subsequent secretion of PilY1 is dependent on the TFP assembly system; thus, PilY1 is not deployed until the pilus is assembled, allowing an ordered signaling cascade. Cell surface-associated PilY1 in turn signals through the TFP alignment complex PilMNOP and the diguanylate cyclase SadC to activate downstream cyclic di-GMP (c-di-GMP) production, thereby repressing swarming motility. Overall, our data support a model whereby P. aeruginosa senses the surface through the Pil-Chp chemotaxis-like complex, TFP, and PilY1 to regulate cAMP and c-di-GMP production, thereby employing a hierarchical regulatory cascade of second messengers to coordinate its program of surface behaviors. IMPORTANCE: Biofilms are surface-attached multicellular communities. Here, we show that a stepwise regulatory circuit, involving ordered signaling via two different second messengers, is required for Pseudomonas aeruginosa to control early events in cell-surface interactions. We propose that our studies have uncovered a multilayered "surface-sensing" system that allows P. aeruginosa to effectively coordinate its surface-associated behaviors. Understanding how cells transition into the biofilm state on a surface may provide new approaches to prevent formation of these communities.

Nanoscale adhesion forces of Pseudomonas aeruginosa type IV Pili.

A variety of bacterial pathogens use nanoscale protein fibers called type IV pili to mediate cell adhesion, a primary step leading to infection. Currently, how these nanofibers respond to mechanical stimuli and how this response is used to control adhesion is poorly understood. Here, we use atomic force microscopy techniques to quantify the forces guiding the adhesion of Pseudomonas aeruginosa type IV pili to surfaces. Using chemical force microscopy and single-cell force spectroscopy, we show that pili strongly bind to hydrophobic surfaces in a time-dependent manner, while they weakly bind to hydrophilic surfaces. Individual nanofibers are capable of withstanding forces up to 250 pN, thereby explaining how they can resist mechanical stress. Pulling on individual pili yields constant force plateaus, presumably reflecting conformational changes, as well as nanospring properties that may help bacteria to withstand physiological shear forces. Analysis of mutant strains demonstrates that these mechanical responses originate solely from type IV pili, while flagella and the cell surface localized and proposed pili-associated adhesin PilY1 play no direct role. We also demonstrate that bacterial-host interactions involve constant force plateaus, the extension of bacterial pili, and the formation of membrane tethers from host cells. We postulate that the unique mechanical responses of type IV pili unravelled here enable the bacteria to firmly attach to biotic and abiotic surfaces and thus maintain attachment when subjected to high shear forces under physiological conditions, helping to explain why pili play a critical role in colonization of the host.

Prevalence and factors associated with herpes simplex virus type 2 infection in patients attending a Baltimore City emergency department.

OBJECTIVES: Herpes simplex virus type 2 (HSV-2) is a common sexually transmitted disease, but there is limited data on its epidemiology among urban populations. The urban Emergency Department (ED) is a potential venue for surveillance as it predominantly serves an inner city minority population. We evaluate the seroprevalence and factors associated with HSV-2 infection among patients attending the Johns Hopkins Hospital Adult Emergency Department (JHH ED). METHODS: An identity unlinked-serosurvey was conducted between 6/2007 and 9/2007 in the JHH ED; sera were tested by the Focus HerpeSelect ELISA. Prevalence risk ratios (PRR) were used to determine factors associated with HSV-2 infection. RESULTS: Of 3,408 serum samples, 1,853 (54.4%) were seropositive for HSV-2. Females (adjPRR  = 1.47, 95% CI 1.38-1.56), non-Hispanic blacks (adjPRR  = 2.03, 95% CI 1.82-2.27), single (adjPRR  = 1.15, 95% CI 1.07-1.25), divorced (adjPRR  = 1.28, 95% CI 1.15-1.41), and unemployed patients (adjPRR  = 1.13, 95% CI 1.05-1.21) had significantly higher rates of HSV-2 infection. Though certain zip codes had significantly higher seroprevalence of HSV-2, this effect was completely attenuated when controlling for age and gender. CONCLUSIONS: Seroprevalence of HSV-2 in the JHH ED was higher than U.S. national estimates; however, factors associated with HSV-2 infection were similar. The high seroprevalence of HSV-2 in this urban ED highlights the need for targeted testing and treatment. Cross-sectional serosurveys in the urban ED may help to examine the epidemiology of HSV-2.

End-stage kidney disease: a survey of recent research to support a palliative approach.

This survey examines the quantity, quality, and accessibility of recent research that contributes to the evidence-based implementation of a palliative approach to end-stage kidney disease (ESKD). An electronic search identified published articles (between September 2009 and August 2011) relevant to adults with ESKD (n = 1628). Few articles (n = 136) referred to key themes in a palliative approach to care: life-limiting illness, holistic care, and unit of care. Most of the relevant empirical articles used designs that did not allow a causal variable to be identified, and evaluations of interventions were rare. The literature was dispersed and often in journals unlikely to be regularly accessed by renal clinicians. Literature supporting the implementation of a full evidence-based palliative approach to ESKD is expanding but remains limited and is difficult to identify and access.

Protein aggregation behavior regulates cyclin transcript localization and cell-cycle control.

Little is known about the active positioning of transcripts outside of embryogenesis or highly polarized cells. We show here that a specific G1 cyclin transcript is highly clustered in the cytoplasm of large multinucleate cells. This heterogeneous cyclin transcript localization results from aggregation of an RNA-binding protein, and deletion of a polyglutamine stretch in this protein results in random transcript localization. These multinucleate cells are remarkable in that nuclei cycle asynchronously despite sharing a common cytoplasm. Notably, randomization of cyclin transcript localization significantly diminishes nucleus-to-nucleus differences in the number of mRNAs and synchronizes cell-cycle timing. Thus, nonrandom cyclin transcript localization is important for cell-cycle timing control and arises due to polyQ-dependent behavior of an RNA-binding protein. There is a widespread association between polyQ expansions and RNA-binding motifs, suggesting that this is a broadly exploited mechanism to produce spatially variable transcripts and heterogeneous cell behaviors. PAPERCLIP:

Sensory processing subtypes in autism: association with adaptive behavior.

Children with autism are frequently observed to experience difficulties in sensory processing. This study examined specific patterns of sensory processing in 54 children with autistic disorder and their association with adaptive behavior. Model-based cluster analysis revealed three distinct sensory processing subtypes in autism. These subtypes were differentiated by taste and smell sensitivity and movement-related sensory behavior. Further, sensory processing subtypes predicted communication competence and maladaptive behavior. The findings of this study lay the foundation for the generation of more specific hypotheses regarding the mechanisms of sensory processing dysfunction in autism, and support the continued use of sensory-based interventions in the remediation of communication and behavioral difficulties in autism.