Effect of NaCl on a protein hydration is of interest in interdisciplinary fields such as food science and extreme environment biology. Here, the protein hydration water dynamics with various NaCl ...concentrations at a constant water activity(Aw) by incoherent quasielastic neutron scattering (iQENS) are examined. Under the same Aw, the water content increases with increasing NaCl concentration. iQENS analysis of these samples shows no significant difference in the dynamics of water molecules despite of the difference of water content. This suggests that the hydration water dynamics should be suppressed in the present of NaCl. Water dynamics is affected by NaCl, but independent of this, there is a universal correlation between Aw values and water molecule dynamics.
It is important to manage individuals’ personal data after their death to maintain their dignity or follow their wishes as much as possible. From this perspective, this report describes the ...real-world commercialization of immortal digital personalities, which gives eternal life to the deceased in a digital form. We identify the problems with the commercialization of deceased users’ images and personal data, which becomes postmortem entertainment. Considering these problems, we seek out the ideal form of deceased users’ personal data for commercialization. We conduct a social survey to understand how ordinary Japanese people feel about the various types of publicly available services that use personal data after death, such as social network service logs. By analyzing our survey results approximately 20% of respondents would allow the commercial use of their personal data, such as browsing their social network service logs, if they could receive compensation during their lifetime.
Water activity (Aw) is a reliable indication of the microbial growth, enzymatic activity, preservation, and quality of foods. However, a molecular basis of Aw is still under debate in multiple ...related disciplines. Glycerol–water mixtures can provide a variation of Aws by controlling the ratio of glycerol and water. In this study, the molecular basis of Aw was examined by using differential scanning calorimetry (DSC), attenuated total reflection Fourier-transform infrared spectroscopy (ATR-IR), and incoherent quasi-elastic neutron scattering (IQENS) based on moisture sorption isotherms of glycerol–water mixtures. Three regions were identified and classified based on DSC results. DSC showed that bulk-like water existed at Aw > ≈ 0.7 at 27°C. Hydrogen bonding related molecular vibrations were analyzed by ATR-IR, which indicated that the OH stretching in water molecules is significantly different for Aw > ≈ 0.7. Translational diffusive and/or rotational motions in time and space analyzed by IQENS appeared when Aw > ≈ 0.7, and are correlated with hydrogen bonding related local vibrational dynamics in the glycerol–water mixtures. More importantly, Aw values of glycerol–water mixtures can be explained by the hydrogen bonding network and molecular dynamics of water in the solution. We discuss the implications of Aw in the preservation of food at the molecular level.
The rigidity and flexibility of a protein is reflected in its structural dynamics. Studies on protein dynamics often focus on flexibility and softness; this review focuses on protein structural ...rigidity. The extent of rigidity can be assessed experimentally with incoherent neutron scattering; a method that is complementary to molecular dynamics simulation. This experimental technique can provide information about protein dynamics in timescales of pico- to nanoseconds and at spatial scales of nanometers; these dynamics can help quantify the rigidity of a protein by indices such as force constant, Boson peak, dynamical transition, and dynamical heterogeneity. These indicators also reflect the rigidity of a protein's secondary and tertiary structures. In addition, the indices reveal how rigidity is influenced by different environmental parameters, such as hydration, temperature, pressure, and protein-protein interactions. Hydration affects both rigidity and softness more than other environmental factors. Interestingly, hydration affects harmonic and anharmonic motions in opposite ways. This difference is probably due to the protein's dynamic coupling with water molecules via hydrogen bonding.
•Protein has two different dynamical features, rigidity and flexibility.•Protein rigidity is required for its specific function.•Protein rigidity is evaluated with incoherent neutron scattering.•Boson peak and protein dynamical transition are good indicators of protein rigidity.•Structural state and hydration control protein rigidity.
Eosinophilic esophagitis (EoE) is a food allergen-induced inflammatory disorder. EoE is increasingly recognized as a cause of swallowing dysfunction, food impaction and esophageal stricture. ...Inflammation of the esophageal mucosa involves immune cell infiltrate, reactive epithelial changes and fibroblast activation, culminating in robust tissue remodeling toward esophageal fibrosis characterized by excess collagen deposition in the subepithelial lamina propria. Fibrosis contributes to a unique mechanical property of the EoE-affected esophagus that is substantially stiffer than the normal esophagus. There is a great need to better understand the processes behind esophageal fibrosis in order to foster improved diagnostic tools and novel therapeutics for EoE-related esophageal fibrosis. In this review, we discuss the role of esophageal inflammatory microenvironment that promotes esophageal fibrosis, with specific emphasis upon cytokines-mediated functional epithelial-stromal interplays, recruitment and activation of a variety of effector cells, and tissue stiffness. We then explore the current state of clinical methodologies to detect and treat the EoE-related esophageal stricture.
The esophagus and stomach, joined by a unique transitional zone, contain actively dividing epithelial stem cells required for organ homeostasis. Upon prolonged inflammation, epithelial cells in both ...organs can undergo a cell fate switch leading to intestinal metaplasia, predisposing to malignancy. Here we discuss the biology of gastroesophageal stem cells and their role as cells of origin in cancer. We summarize the interactions between the stromal niche and gastroesophageal stem cells in metaplasia and early expansion of mutated stem-cell-derived clones during carcinogenesis. Finally, we review new approaches under development to better study gastroesophageal stem cells and advance the field.
Rustgi, Que, and Wang discuss the biology of gastroesophageal stem cells and their role as the cell-of-origin in cancer. They summarize niche-stem cell interactions in metaplasia and early expansion of mutated stem-cell-derived clones during carcinogenesis. New approaches to study gastroesophageal stem cells and advance the field are also discussed.
In primates, neurons giving rise to the corticospinal tract (CST) are distributed in several motor-related areas of the frontal lobe, such as the primary motor cortex (M1), the supplementary motor ...area (SMA), and the dorsal and ventral divisions of the premotor cortex (PMd, PMv). Recently, we have shown in macaque monkeys that the morphology of basal dendrites of CST neurons, i.e., large layer V pyramidal neurons, varies among the digit regions of the motor-related areas. Here, we investigated the alterations in basal dendrite morphology of CST neurons after spinal cord injury (SCI). In our monkey model, both the complexity and the spine density of basal dendrites were highly decreased throughout the areas. Notably, these events were less prominent for the PMd than for the M1, SMA, and PMv. In analyzing the density changes post-SCI of the filopodia-, thin-, stubby-, and mushroom-type spines, it was found that the density of filopodia-type spines was increased for all areas, whereas the other types of spines exhibited density decreases. Such spine density reductions were so limited for the PMd as compared to the other areas. The observed plastic changes of CST neurons may contribute to the recovery from impaired motor functions caused by SCI.
Brain injury that results in an initial behavioural deficit is frequently followed by spontaneous recovery. The intrinsic mechanism of this functional recovery has never been fully understood. Here, ...we show that reorganization of the corticospinal tract induced by target-derived brain-derived neurotrophic factor is crucial for spontaneous recovery of motor function following brain injury. After destruction of unilateral sensorimotor cortex, intact-side corticospinal tract formed sprouting fibres into the specific lamina of the denervated side of the cervical spinal cord, and made new contact with two types of spinal interneurons--segmental and propriospinal neurons. Anatomical and electrophysiological analyses revealed that this rewired corticospinal tract functionally linked to motor neurons and forelimb muscles. This newly formed corticospinal circuit was necessary for motor recovery, because transection of the circuit led to impairment of recovering forelimb function. Knockdown of brain-derived neurotrophic factor in the spinal neurons or its receptor in the intact corticospinal neurons diminished fibre sprouting of the corticospinal tract. Our findings establish the anatomical, functional and molecular basis for the intrinsic capacity of neurons to form compensatory neural network following injury.
The purpose of this study was to clarify the glass-transition behavior of bacteria (Cronobacter sakazakii) as a function of water activity (aw). From the water sorption isotherm (298 K) for C. ...sakazakii, monolayer water content and monolayer aw were determined to be 0.0724 g/g-dry matter and 0.252, respectively. Mechanical relaxation was investigated at 298 K. In a higher aw range of over 0.529, the degree of mechanical relaxation increased with an increase in aw. From the effect of aw on the degree of mechanical relaxation, the mechanical awc (aw at which mechanical glass transition occurs at 298 K) was determined to be 0.667. Mean-square displacement of atoms in the bacteria was investigated by incoherent elastic neutron scattering. The mean-square displacement increased gradually with an increase in temperature depending on the aw of samples. From the linear fitting, two or three dynamical transition temperatures (low, middle, and high Tds) were determined at each aw. The low-Td values (142–158 K) were almost independent from aw. There was a minor effect of aw on the middle Td (214–234 K) except for the anhydrous sample (261 K). The high Td (252–322 K) largely increased with the decrease in aw. From the aw dependence of the high Td, the dynamical awc was determined to be 0.675, which was almost equivalent to the mechanical awc. The high Td was assumed to be the glass-transition temperature (Tg), and anhydrous Tg was estimated to be 409 K. In addition, molecular relaxation time (τ) of the bacteria was calculated as a function of aw. From the result, it is suggested that the progress of metabolism in the bacterial system requires a lower τ than approximately 6 × 10−5 s.
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