At the body surface, skin's stratified squamous epithelium is challenged by environmental extremes. The surface of the skin is composed of enucleated, flattened surface squames. They derive from ...underlying, transcriptionally active keratinocytes that display filaggrin-containing keratohyalin granules (KGs) whose function is unclear. Here, we found that filaggrin assembles KGs through liquid-liquid phase separation. The dynamics of phase separation governed terminal differentiation and were disrupted by human skin barrier disease-associated mutations. We used fluorescent sensors to investigate endogenous phase behavior in mice. Phase transitions during epidermal stratification crowded cellular spaces with liquid-like KGs whose coalescence was restricted by keratin filament bundles. We imaged cells as they neared the skin surface and found that environmentally regulated KG phase dynamics drive squame formation. Thus, epidermal structure and function are driven by phase-separation dynamics.
• Background S-RNase-based self-incompatibility (SI) occurs in the Solanaceae, Rosaceae and Plantaginaceae.In all three families, compatibility is controlled by a polymorphic S-locus encoding at ...least two genes.S-RNases determine the specificity of pollen rejection in the pistil, and S-locus F-box proteins fulfill this function in pollen. S-RNases are thought to function as S-specific cytotoxins as well as recognition proteins. Thus, incompatibility results from the cytotoxic activity of S-RNase, while compatible pollen tubes evade S-RNase cytotoxicity. • Scope The S-specificity determinants are known, but many questions remain. In this review, the genetics of SI are introduced and the characteristics of S-RNases and pollen F-box proteins are briefly described. A variety of modifier genes also required for SI are also reviewed. Mutations affecting compatibility in pollen are especially important for defining models of compatibility and incompatibility. In Solanaceae, pollen-side mutations causing breakdown in SI have been attributed to the heteroallelic pollen effect, but a mutation in Solanum chacoense may be an exception. This has been interpreted to mean that pollen incompatibility is the default condition unless the S-locus F-box protein confers resistance to S-RNase. In Prunus, however, S-locus F-box protein gene mutations clearly cause compatibility. • Conclusions Two alternative mechanisms have been proposed to explain compatibility and incompatibility: compatibility is explained either as a result of either degradation of non-self S-RNase or by its compartmentalization so that it does not have access to the pollen tube cytoplasm. These models are not necessarily mutually exclusive, but each makes different predictions about whether pollen compatibility or incompatibility is the default. As more factors required for SI are identified and characterized, it will be possible to determine the role each process plays in S-RNase-based SI.
Reported here is the synthesis of perfectly sequence defined, monodisperse diblock copolypeptides of hydrophilic elastin-like and hydrophobic resilin-like polypeptide blocks and characterization of ...their self-assembly as a function of structural parameters by light scattering, cryo-TEM, and small-angle neutron scattering. A subset of these diblock copolypeptides exhibit lower critical solution temperature and upper critical solution temperature phase behavior and self-assemble into spherical or cylindrical micelles. Their morphologies are dictated by their chain length, degree of hydrophilicity, and hydrophilic weight fraction of the ELP block. We find that (1) independent of the length of the corona-forming ELP block there is a minimum threshold in the length of the RLP block below which self-assembly does not occur, but that once that threshold is crossed, (2) the RLP block length is a unique molecular parameter to independently tune self-assembly and (3) increasing the hydrophobicity of the corona-forming ELP drives a transition from spherical to cylindrical morphology. Unlike the self-assembly of purely ELP-based block copolymers, the self-assembly of RLP-ELPs can be understood by simple principles of polymer physics relating hydrophilic weight fraction and polymer-polymer and polymer-solvent interactions to micellar morphology, which is important as it provides a route for the de novo design of desired nanoscale morphologies from first principles.
•Child protection workers were trained in solution-focused brief therapy.•Solution-focused practices improved outcomes rated by workers and parents.•Solution-focused practices decreased risk, child ...removal and recidivism.•Solution-focused practices were more cost-effective than treatment as usual.
The purpose of this research was to evaluate the impact on child welfare of introducing solution-focused principles and intervention techniques in the local child protection service of the island of Tenerife, Spain. 152 workers from 34 local child protection teams participated in the study. Goal achievement, parents’ and children’s self-reported well-being, and statutory child welfare measures were recorded during one year. Then the child protection teams were randomly assigned to a control or an experimental condition. 73 workers in the experimental condition, serving 271 families, received 30 h of training and 30 h of supervision in solution-focused brief therapy (SFBT). 79 workers in the control condition, serving 206 families, continued to intervene as usual. The dependent variables were evaluated again in the experimental and in the control group one year after the supervision in SFBT had finished. Results indicate that the experimental and the control group had equivalent outcomes at pre-test. At post-test, the experimental group achieved better outcomes than the control group: workers’ and parents’ goal achievement ratings as well as parents’ and children well-being ratings were higher, fewer cases had been referred to risk teams, fewer children had been removed from their homes and recidivism was lower. The effects were small for goal achievement, medium for recidivism, and large for well-being and child removal. The teams that used SFBT reached these outcomes with fewer sessions and allocating fewer additional resources than the control group.
Since the early 1980s, multiple researchers have contributed to the development of
models of the human gastrointestinal system for the mechanistic interrogation of the gut microbiome ecology. Using a ...bioreactor for simulating all the features and conditions of the gastrointestinal system is a massive challenge. Some conditions, such as temperature and pH, are readily controlled, but a more challenging feature to simulate is that both may vary in different regions of the gastrointestinal tract. Promising solutions have been developed for simulating other functionalities, such as dialysis capabilities, peristaltic movements, and biofilm growth. This research field is under constant development, and further efforts are needed to drive these models closer to
conditions, thereby increasing their usefulness for studying the gut microbiome impact on human health. Therefore, understanding the influence of key operational parameters is fundamental for the refinement of the current bioreactors and for guiding the development of more complex models. In this review, we performed a systematic search for operational parameters in 229 papers that used continuous bioreactors seeded with human feces. Despite the reporting of operational parameters for the various bioreactor models being variable, as a result of a lack of standardization, the impact of specific operational parameters on gut microbial ecology is discussed, highlighting the advantages and limitations of the current bioreactor systems.
Self-incompatibility (SI) mechanisms prevent self-fertilization in flowering plants based on specific discrimination between self- and non-self pollen. Since this trait promotes outcrossing and ...avoids inbreeding it is a widespread mechanism of controlling sexual plant reproduction. Growers and breeders have effectively exploited SI as a tool for manipulating domesticated crops for thousands of years. However, only within the past thirty years have studies begun to elucidate the underlying molecular features of SI. The specific
-determinants and some modifier factors controlling SI have been identified in the sporophytic system exhibited by
species and in the two very distinct gametophytic systems present in Papaveraceae on one side and in Solanaceae, Rosaceae, and Plantaginaceae on the other. Molecular level studies have enabled SI to SC transitions (and
) to be intentionally manipulated using marker assisted breeding and targeted approaches based on transgene integration, silencing, and more recently CRISPR knock-out of SI-related factors. These scientific advances have, in turn, provided a solid basis to implement new crop production and plant breeding practices. Applications of self-(in)compatibility include widely differing objectives such as crop yield and quality improvement, marker-assisted breeding through SI genotyping, and development of hybrids for overcoming intra- and interspecific reproductive barriers. Here, we review scientific progress as well as patented applications of SI, and also highlight future prospects including further elucidation of SI systems, deepening our understanding of SI-environment relationships, and new perspectives on plant self/non-self recognition.
In Solanaceae, self-incompatibility is a genetic mechanism that prevents endogamy in plant populations. Expression of the S-determinants, S-RNase, and SLF, is tightly regulated during pistil and ...pollen development. However, the molecular mechanism of gene expression regulation in S-RNase-based self-incompatibility systems must be better understood. Here, we identified a 1.3 Kbp sequence upstream to the coding region of the functional SC10-RNase allele from the self-incompatible Nicotiana alata, which directs SC10-RNase expression in mature pistils. This SC10-RNase promoter includes a 300 bp region with minimal elements that sustain the SC10-RNase expression. Likewise, a fragment of a transposable element from the Gypsy family of retrotransposons is also present at the -320 bp position. Nevertheless, its presence does not affect the expression of the SC10-RNase in mature pistils. Additionally, we determined that the SC10-RNase promoter undergoes different DNA methylation states during pistil development, being the mCHH methylation context the most frequent close to the transcription start site at pistil maturity. We hypothesized that the Gypsy element at the SC10-RNase promoter might contribute to the DNA methylation remodeling on the three sequence contexts analyzed here. We propose that mCHH methylation enrichment and other regulatory elements in the S-RNase coding region regulate the specific and abundant SC10-RNase expression in mature pistils in N. alata.
Bacteria frequently store excess carbon in hydrophobic granules of polyhydroxybutyrate (PHB) that in some growth conditions can occupy most of the cytoplasmic space. Different types of proteins ...associate to the surface of the granules, mainly enzymes involved in the synthesis and utilization of the reserve polymer and a diverse group of proteins known as phasins. Phasins have different functions, among which are regulating the size and number of the granules, modulating the activity of the granule-associated enzymes and helping in the distribution of the granules inside the cell. Caulobacter crescentus is an oligotrophic bacterium that shows several morphological and regulatory traits that allow it to grow in very nutrient-diluted environments. Under these conditions, storage compounds should be particularly relevant for survival. In this work, we show an initial proteomic characterization of the PHB granules and describe a new type of phasin (PhaH) characterized by the presence of an N-terminal hydrophobic helix followed by a helix-hairpin-helix (HhH) domain. The hydrophobic helix is required for maximal PHB accumulation and maintenance during the stationary phase while the HhH domain is involved in determining the size of the PHB granules and their distribution in the cell.
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