Scleraxis-lineage cells are required for correct muscle patterning.

Movement of the vertebrate body is supported by the connection of muscle, tendon and bone. Each skeletal muscle in the vertebrate body has a unique shape and attachment site; however, the mechanism that ensures reproducible muscle patterning is incompletely understood. In this study, we conducted targeted cell ablation using scleraxis (Scx)-Cre to examine the role of Scx-lineage cells in muscle morphogenesis and attachment in mouse embryos. We found that muscle bundle shapes and attachment sites were significantly altered in embryos with Scx-lineage cell ablation. Muscles in the forelimb showed impaired bundle separation and limb girdle muscles distally dislocated from their insertion sites. Scx-lineage cells were required for post-fusion myofiber morphology, but not for the initial segregation of myoblasts in the limb bud. Furthermore, muscles could change their attachment site, even after formation of the insertion. Lineage tracing suggested that the muscle patterning defect was primarily attributed to the reduction of tendon/ligament cells. Our study demonstrates an essential role of Scx-lineage cells in the reproducibility of skeletal muscle attachment, in turn revealing a previously unappreciated tissue-tissue interaction in musculoskeletal morphogenesis.

Temperature-Dependent Left- and Right-Twisted Conformational Changes in 1:1 Host-Guest Systems: Theoretical Modeling and Chiroptical Simulations.

An efficient strategy for high-performance chiral materials is to design and synthesize host molecules with left- and right- (M- and P-) twisted conformations and to control their twisted conformations. For this, a quantitative analysis is required to describe the chiroptical inversion, chiral transfer, and chiral recognition in the host-guest systems, which is generally performed using circular dichroism (CD) and/or proton nuclear magnetic resonance (1H-NMR) spectroscopies. However, the mass-balance model that considers the M- and P-twisted conformations has not yet been established. In this study, we derived the novel equations based on the mass-balance model for the 1:1 host-guest systems. Then, we further applied them to analyze the 1:1 host-guest systems for the achiral calixarene-based capsule molecule, achiral dimeric zinc porphyrin tweezer molecule, and chiral pillar[5]arene with the chiral and/or achiral guest molecules by using the data obtained from the CD titration, variable temperature CD (VT-CD), and 1H-NMR experiments. The thermodynamic parameters (ΔH and ΔS), equilibrium constants (K), and molar CD (Δε) in the 1:1 host-guest systems could be successfully determined by the theoretical analyses using the derived equations.

Digoxigenin-labeled RNA probes for untranslated regions enable the isoform-specific gene expression analysis of myosin heavy chains in whole-mount in situ hybridization.

Myosin heavy chains (MyHCs), which are encoded by myosin heavy chain (Myh) genes, are the most abundant proteins in myofiber. Among the 11 sarcomeric Myh isoform genes in the mammalian genome, seven are mainly expressed in skeletal muscle. Myh genes/MyHC proteins share a common role as force producing units with highly conserved sequences, but have distinct spatio-temporal expression patterns. As such, the expression patterns of Myh genes/MyHC proteins are considered as molecular signatures of specific fiber types or the regenerative status of mammalian skeletal muscles. Immunohistochemistry is widely used for identifying MyHC expression patterns; however, this method is costly and is not ideal for whole-mount samples, such as embryos. In situ hybridization (ISH) is another versatile method for the analysis of gene expression, but is not commonly applied for Myh genes, partly because of the highly homologous sequences of Myh genes. Here we demonstrate that an ISH analysis with the untranslated region (UTR) sequence of Myh genes is cost-effective and specific method for analyzing the Myh gene expression in whole-mount samples. Digoxigenin (DIG)-labeled antisense probes for UTR sequences, but not for protein coding sequences, specifically detected the expression patterns of respective Myh isoform genes in both embryo and adult skeletal muscle tissues. UTR probes also revealed the isoform gene-specific polarized localization of Myh mRNAs in embryonic myofibers, which implied a novel mRNA distribution mechanism. Our data suggested that the DIG-labeled UTR probe is a cost-effective and versatile method to specifically detect skeletal muscle Myh genes in a whole-mount analysis.

Self-Assembling Behavior and Chiroptical Properties of Carbazole-Cored Phenyl Isoxazolyl Benzenes.

Carbazole-cored phenyl isoxazolyl benzenes possessing chiral moieties were synthesized. The molecules self-assembled to form stacked supramolecular assemblies in an isodesmic fashion in chloroform, whereas the molecules preferably assembled in a cooperative fashion in methylcyclohexane (MCH), which was determined by spectroscopic methods, including UV-vis absorption, fluorescence, and 1H NMR spectroscopy. Clear nucleation and elongation processes were observed in the plot of the degree of aggregation (αagg) against temperature, which allowed us to determine the elongation temperature (Te), the enthalpic gain in the elongation process (ΔHe), the equilibrium constant between nucleation and elongation (Ka), and the degree of polymerization at the elongation temperature ([Nn(Te)]). Circular dichroism (CD) and circularly polarized luminescence (CPL) studies revealed the formation of helically stacked assemblies in solution. Moreover, the majority-rule effect was clearly observed in the solutions of mixtures of (S)- and (R)-1, indicating the chiral amplification behavior of the helically stacked assemblies consisting of (S)- and (R)-1. AFM provided morphological insight into the assemblies on mica, which clearly indicates the formation of polymeric assemblies in the solid state.

Solvent-directed formation of helically twisted stacking constructs via self-assembly of tris(phenylisoxazolyl)benzene dimers.

Ureido-pyrimidinone (UPy)-appended tris(phenylisoxazolyl)benzenes were synthesized. The UPy moieties of the tris(phenylisoxazolyl)benzenes stably formed self-complementary dimers in solution. The dimers self-assembled to form helically twisted stacking constructs in a process driven by π-π stacking interactions of UPy dimer moieties and dipole-dipole interactions of isoxazole units. Strong association affinity was seen within the stacking constructs compared with the previously reported isoxazole derivatives owing to the auxiliary π-π stacking interaction. Notably, tris(phenylisoxazolyl)benzenes showed an environmentally responsive nature. The absorption bands, emission intensities, and sizes of ensembles depended significantly on the mixing ratio of CHCl3 and methylcyclohexane (MCH). Additionally, sharp on-off switching phenomena were seen in their circular dichroism (CD) and circularly polarized luminescence (CPL) spectra in response to the mixing ratio of CHCl3 and MCH. CD and CPL were activated only at a certain mixing ratio of CHCl3/MCH, thus showing potential for the creation of molecular sensors.

Neuropeptide Y modulates membrane excitability in neonatal rat mesencephalic V neurons.

Neuropeptide Y (NPY) is one of a number of neuropeptides with powerful orexigenic effects. Intracerebroventricular administration of NPY induces increases in food intake and alters feeding rate. Besides it role in feeding behavior, NPY also has significant effects on neuronal systems related to other spontaneous behaviors such as rearing and grooming. In the present study, we examined the direct effects of NPY on mesencephalic V neurons (Mes V), which are important sensory neurons involved in oral motor reflexes and rhythmical jaw movements, as well as masticatory proprioception. Coronal brain slices were prepared from neonatal Sprague-Dawley rats (P3-17) and whole-cell patch clamp recordings were obtained from Mes V neurons. Bath application of NPY depolarized the membrane potential and induced inward current in most neurons. Application of NPY shortened the duration of the afterhyperpolarization following an action potential, and increased the mean spike frequency during repetitive discharge. In those neurons which exhibited rhythmical burst discharge in response to maintained current injection, the bursting frequency was also increased. These effects were mediated predominately by both Y1 and Y5 receptors.

Latent porosity of planar tris(phenylisoxazolyl)benzene.

Interest in developing separation systems for chemical entities based on crystalline molecules has provided momentum for the fabrication of synthetic porous materials showing selectivity in molecular encapsulation, such as metal-organic frameworks, covalent organic frameworks, hydrogen-bonded organic frameworks, zeolites, and macrocyclic molecular crystals. Among these, macrocyclic molecular crystals have generated renewed interest for use in separation systems. Selective encapsulation relies on the sizes, shapes, and dimensions of the pores present in the macrocyclic cavities; thus, nonmacrocyclic molecular crystals with high selectivity for molecular encapsulation via porosity-without-pore behaviors have not been studied. Here, we report that planar tris(phenylisoxazolyl)benzene forms porous molecular crystals possessing latent pores exhibiting porosity-without-pore behavior. After exposing the crystals to complementary guest molecules, the latent pores encapsulate cis- and trans-decalin while maintaining the structural rigidity responsible for the high selectivity. The encapsulation via porosity without pores is a kinetic process with remarkable selectivity for cis-decalin over trans-decalin with a cis-/trans-ratio of 96:4, which is confirmed by single-crystal X-ray diffraction and powder X-ray diffraction analyses. Hirshfeld surface analysis and fingerprint plots show that the latent intermolecular pores are rigidified by intermolecular dipole‒dipole and π-π stacking interactions, which determines the remarkable selectivity of molecular recognition.

Selective encapsulation of carboxylic acid dimers within a size-regulable resorcinarene-based hemicarcerand.

A cavity within a resorcinarene-based hemicarcerand was contracted and expanded through conformational changes induced by the complexation and decomplexation, allowing self-sorting of homo- and heterodimeric carboxylic acid pairs.

Persistent sodium conductance contributes to orexin-A-mediated modulation of membrane excitability in neonatal rat mesencephalic V neurons.

Orexins are multifunctional hypothalamic neuropeptides that participate in the stimulation of feeding behavior and energy expenditure. However, little is known about their neuromodulatory effects in lower brainstem effector regions, including in the trigeminal neuronal system. The aim of this study was to examine the effects of orexin-A (Ox-A) on the membrane properties of mesencephalic trigeminal (Mes V) neurons that are critically involved in the generation and control of rhythmical oral motor activities. Whole-cell patch clamp recordings were obtained from Mes V neurons in coronal brain slices prepared from Sprague-Dawley rats (postnatal day 12-17). Bath application of Ox-A (100 nM) shortened the duration of the after-hyperpolarization following the action potential, while the interspike frequency of firings during repetitive discharge increased, together with a shift in the frequency-current relationship toward the left. In addition, Ox-A amplified the resonance at the depolarized membrane potential, accompanied with an increase in both Q-value and resonant frequency. A further voltage-clamp experiment demonstrated that Ox-A increased the peak current density of the persistent sodium current (INaP) and shifted its activation curve to the hyperpolarization direction. These results suggested that Ox-A may increase Mes V neuronal excitability by enhancing INaP, possibly sharing a common mechanism with another orexigenic hypothalamic neuropeptide, neuropeptide Y.

Columnar Organization of Carbo[5]helicene Directed by Peripheral Steric Perturbation.

Three carbo[5]helicenes ([5]CHs) containing benzylmaleimide groups displayed columnar stacked organizations, including dislocated, parallel, and alternating (P)- and (M)-helix molecular arrangements in the solid state. The peripheral benzyl groups resulted in very small steric interactions that are responsible for the formation of columnar stacked arrangements in the crystalline state.

Case report of extragingival peripheral ameloblastoma in buccal mucosa.

A peripheral ameloblastoma (PA) is a rare variant of ameloblastoma that generally occurs in the extraosseous region; an extragingival PA is extremely rare. There have been 5 cases reported of a PA occurring in the buccal mucosa and 1 in the oral floor. We present the sixth known case of extragingival PA in the buccal mucosa, which occurred in an 88-year-old woman.