From Basic Principles of Protein-Polysaccharide Association to the Rational Design of Thermally Sensitive Materials.

Biology resolves design requirements toward functional materials by creating nanostructured composites, where individual components are combined to maximize the macroscale material performance. A major challenge in utilizing such design principles is the trade-off between the preservation of individual component properties and emerging composite functionalities. Here, polysaccharide pectin and silk fibroin were investigated in their composite form with pectin as a thermal-responsive ion conductor and fibroin with exceptional mechanical strength. We show that segregative phase separation occurs upon mixing, and within a limited compositional range, domains ∼50 nm in size are formed and distributed homogeneously so that decent matrix collective properties are established. The composite is characterized by slight conformational changes in the silk domains, sequestering the hydrogen-bonded ß-sheets as well as the emergence of randomized pectin orientations. However, most dominant in the composite's properties is the introduction of dense domain interfaces, leading to increased hydration, surface hydrophilicity, and increased strain of the composite material. Using controlled surface charging in X-ray photoelectron spectroscopy, we further demonstrate Ca ions (Ca2+) diffusion in the pectin domains, with which the fingerprints of interactions at domain interfaces are revealed. Both the thermal response and the electrical conductance were found to be strongly dependent on the degree of composite hydration. Our results provide a fundamental understanding of the role of interfacial interactions and their potential applications in the design of material properties, polysaccharide-protein composites in particular.

Comparison of clinical remission criteria for severe asthma patients receiving biologic therapy.

BACKGROUND: The concept of remission on biological treatment has been suggested as a therapeutic target for patients with severe asthma, composed of 1. no chronic use of systemic steroids, 2. no exacerbations, 3. minimal symptoms, and 4. optimized lung function, for a significant time. However, the criteria for remission are not clearly defined. OBJECTIVE: Our objective was to compare different criteria for remission in subjects receiving biologicals for severe asthma. METHODS: A cross-sectional study of adult subjects who receive a stable regimen of a biological for severe asthma for at least 6-months. We compared the proportion of subjects who fulfilled different specific criteria in the four domains, as well as those who achieved different composite outcome measures of clinical remission. RESULTS: Of 39 subjects, 28 were females (71.8%), mean age 60.4. Twelve were current or past smokers (30.8%). Twelve had prior different biological treatment (30.8%), and 3/39 had more than one previous treatment (7.7%). Current biological included mepolizumab 12/39 (30.8%), dupilumab 11/39 (28.2%), benralizumab 10/39 (25.6%), omalizumab 5/39 (12.8%), reslizumab 1/39 (2.6%). Different specific criteria were achieved in 39-80% of subjects, being highest for no chronic steroid use and lowest for symptoms control and lung function. Overall remission was obtained by 20-41%, depending on definition, with significant variability in agreement between different sets of remission criteria (Cohen's kappa 0.33-0.89). CONCLUSION: Clinical remission is achievable in real-world severe asthmatics on biological therapies. The core criteria for remission should be better defined.

Morphological, cytological and metabolic consequences of autopolyploidization in Hylocereus (Cactaceae) species.

BACKGROUND: Genome doubling may have multi-level effects on the morphology, viability and physiology of polyploids compared to diploids. We studied the changes associated with autopolyploidization in two systems of somatic newly induced polyploids, diploid-autotetraploid and triploid-autohexaploid, belonging to the genus Hylocereus (Cactaceae). Stomata, fruits, seeds, embryos, and pollen were studied. Fruit pulp and seeds were subjected to metabolite profiling using established gas chromatography-mass spectrometry (GC-MS) and ultra-performance liquid chromatography (UPLC) Q-TOF-MS/MS (time of flight)-protocols. RESULTS: Autopolyploid lines produced lower numbers of tetrads, larger pollen grains with lower viability, larger stomata with lower density, and smaller fruits with lower seed numbers and decreased seed viability. The abundance of sugars was lower in the fruits and seeds of the two duplicated lines than in their donor lines, accompanied by increased contents of amino acids, tricarboxylic acid (TCA) cycle intermediates, organic acids and flavonoids. Betacyanins, the major fruit pigments in diploid and triploid donors, decreased following genome doubling. Both autopolyploid Hylocereus lines thus exhibited unfavorable changes, with the outcome being more dramatic in the autohexaploid than in the autotetraploid line. CONCLUSION: Induced autotetraploid and autohexaploid lines exhibited morphological and cytological characteristics that differed from those of their donor plants and that were accompanied by significant metabolic alterations. It is suggested that a developmental arrest occurs in the fruits of the autohexaploid line, since their pericarp shows a greater abundance of acids and of reduced sugars. We conclude that genome doubling does not necessarily confer a fitness advantage and that the extent of alterations induced by autopolyploidization depends on the genetic background of the donor genotype.