Multivalent DNA and nucleosome acidic patch interactions specify VRK1 mitotic localization and activity.

A key role of chromatin kinases is to phosphorylate histone tails during mitosis to spatiotemporally regulate cell division. Vaccinia-related kinase 1 (VRK1) is a serine-threonine kinase that phosphorylates histone H3 threonine 3 (H3T3) along with other chromatin-based targets. While structural studies have defined how several classes of histone-modifying enzymes bind to and function on nucleosomes, the mechanism of chromatin engagement by kinases is largely unclear. Here, we paired cryo-electron microscopy with biochemical and cellular assays to demonstrate that VRK1 interacts with both linker DNA and the nucleosome acidic patch to phosphorylate H3T3. Acidic patch binding by VRK1 is mediated by an arginine-rich flexible C-terminal tail. Homozygous missense and nonsense mutations of this acidic patch recognition motif in VRK1 are causative in rare adult-onset distal spinal muscular atrophy. We show that these VRK1 mutations interfere with nucleosome acidic patch binding, leading to mislocalization of VRK1 during mitosis, thus providing a potential new molecular mechanism for pathogenesis.

Microtropins Q-W, ent-Labdane Glucosides: Microtropiosides G-I, Ursane-Type Triterpene Diglucoside and Flavonol Glycoside from the Leaves of Microtropis japonica.

Microtropins Q-W, (2S,3R)-2-ethyl-2,3-dihydroxybutyrate of various glucosides and glucose, as well as three ent-labdane diterpenoid glucosides, named microtropiosides G, H and I, an ursane-type triterpene diglucoside and a flavonoid glycoside were isolated from the MeOH extract of the leaves of Microtropis japonica. The structure of microtropioside A, also isolated from the branches of M. japonica, was elucidated spectroscopically in a previous experiment and was found to possess a rare seven-membered oxyrane ring. Its structure was confirmed by X-ray crystallographic analysis of its pentaacetate.

An unusual configuration of two anomalies in the extensor digitorum profundus complex in a human.

The extensor digitorum profundus complex underwent degeneration of the ulnar segments during primate adaptation and evolution. This process resulted in the preservation of only the extensor pollicis longus and extensor indicis in some apes, including humans. Consequently, anatomical variations within the digitorum profundus complex in modern humans have been well-documented, with detailed reports on their frequency and patterns in previous studies. Here, we report an unusual arrangement involving two anomalies in the extensor digitorum profundus complex, identified in a 66-year-old Japanese male cadaver. In this cadaver, two accessory muscles differentiated from both the extensor pollicis longus and extensor indicis. Notably, the latter muscle featured a tendon bifurcating towards both the thumb and index fingers, referred to as the extensor pollicis et indicis communis. Under the extensor retinaculum, the tendon of the accessory extensor pollicis longus passed through an independent compartment, whereas that of the extensor pollicis et indicis communis traversed a compartment shared by the extensor indicis and the extensor digitorum communis. Both muscles were innervated by the posterior interosseous nerve. Previous studies have reported that the accessory slip of the extensor pollicis longus and extensor pollicis et indicis communis appear at frequencies of 0.6% and 0.4-1.4%, respectively. However, to the best of our knowledge, a configuration in which both appear simultaneously has not been reported. The data from this case could provide essential insights into the variations in the extensor digitorum profundus complex in humans and non-human primates.

A candidate of organum vasculosum of the lamina terminalis with neuronal connections to neurosecretory preoptic nucleus in eels.

Systemic angiotensin II (Ang II) is a dipsogen in terrestrial vertebrates and seawater teleosts. In eels, Ang II acts on the area postrema, a sensory circumventricular organ (CVO) and elicits water intake but other sensory CVOs have not yet been found in the eel forebrain. To identify sensory CVOs in the forebrain, eels were peripherally injected with Evans blue, which immediately binds to albumin, or a rabbit IgG protein. Extravasation of these proteins, which cannot cross the blood­brain barrier (BBB), was observed in the brain parenchyma of the anteroventral preoptic recess (PR) walls. Fenestrated capillaries were observed in the parenchymal margin of the ventral wall of the PR, confirming a deficit of the BBB in the eel forebrain. Immunostaining for tyrosine hydroxylase (TH) and choline acetyltransferase (ChAT) detected neurons in the lateral region of the anterior parvocellular preoptic nucleus (PPa), which were strongly stained by BBB-impermeable N-hydroxysulfosuccinimide. In the periventricular region of the PPa, many neurons incorporated biotinylated dextran amine conjugated to fluorescein, a retrograde axonal tracer, injected into the magnocellular preoptic nucleus (PM), indicating neuronal connections from the PPa to the PM. The mammalian paraventricular and supraoptic nuclei, homologous to the teleost PM, receive principal neuronal projections from the organum vasculosum of the lamina terminalis (OVLT). These results strongly suggest that the periventricular subpopulation of the PPa, which is most likely to be a component of the OVLT, serves as a functional window of access for systemic signal molecules such as Ang II.

Autophagy induction on impaired spermatogenesis of xeroderma pigmentosum group A gene-deficient mice.

Xeroderma pigmentosum (XP) involves a defect in the initial step of nucleotide excision repair (NER) and consists of eight genetic complementation groups (groups A-G and a variant). XP group A (XPA) patients have a high incidence of UV-induced skin tumors, immature testicular development, and neurological symptoms. In an earlier study, we have shown that XP group A (Xpa) gene-knockout mice (Xpa-/- mice) were highly sensitive to UV-induced skin carcinogenesis with a defect in NER and were highly susceptibility to spontaneous tumorigenesis with impaired spermatogenesis. However, the pathology of impaired spermatogenesis in Xpa-/- mice is unknown. To unravel the underlying pathology, we made a concerted effort using the testis of 3-month-old Xpa-/- mice. We found many large vacuoles in the seminiferous tubules of 3-month old Xpa-/- mice, while there were no large vacuoles in that of Xpa+/+ mice. Immunohistochemistry of microtubule-associated protein 1 light chain 3 (LC3), an autophagosome marker, showed degenerating cells with intense signal of LC3 in the seminiferous tubules, and immunoblotting revealed induction of LC3-II in the 3-month-old Xpa-/- mice. The results of the present study suggest autophagy induction as the possible mechanism underlying the impaired spermatogenesis in Xpa-/- mice. Therefore, Xpa-/- mice could be a useful model for investigating aging and male infertility with low expression of XPA.

Constitutive accessibility of circulating proteins to hippocampal neurons in physiologically normal rats.

INTRODUCTION: Although the hippocampus (HIP) is thought impermeable to blood-borne proteins because of the integrity of the blood-brain barrier (BBB), it was recently suggested to be susceptible to hydrophilic hormones. The present study determined the accessibility of blood-borne signal molecules such as hormones to hippocampal neurons in physiologically normal rats. METHODS: As a probe for accessibility, Evans blue dye (EB) that rapidly binds to albumin (Alb), which is impermeable to the BBB, was injected intravenously. To increase the vascular permeability of the BBB, a daily single administration of angiotensin II (Ang II) was applied intravenously for seven consecutive days. RESULTS: Fifteen minutes after the injection of EB, histological observation revealed that a number of neurons had entrapped and accumulated EB into their cell bodies in the hippocampal dentate gyrus in all rats. Of these, relatively large oval neurons (>15 µm) in the hilus and molecular layer showed parvalbumin immunopositivity, indicating they are GABAergic interneurons. The population of EB-accumulating neurons (approximately 10 µm) were localized in the inner margin of the granule cell layer, suggesting they were granule cells. However, the number of EB-positive neurons did not change in rats treated with Ang II compared with vehicle injection. CONCLUSIONS: These findings suggest an intriguing possibility that blood-derived proteins such as hormones have access to hippocampal neurons constitutively in the absence of stimuli that increase the vascular permeability of the BBB in a physiologically normal state.

Impact of Hands-on Experience of a Cadaver Dissection on the Professional Identity Formation of Health Sciences Students.

BACKGROUND: In Japan, some nursing and health science universities that train nurses and/or clinical laboratory technicians have a curriculum in which students observe medical students performing a cadaver dissection. Observing a cadaver dissection is believed to affect the formation of a student's professional identity. This study aimed to investigate the effects of observing a cadaver dissection on the professional identity of nursing and clinical laboratory science students to find an effective educational support system for developing professional identity. METHODS: Sophomores majoring in nursing science or clinical laboratory science were asked to complete a questionnaire with a professional identity scale before and after hands-on experience of a cadaver dissection performed by medical students. After their hands-on session was complete, they responded to a free-answer question about acquiring a professional identity. RESULTS: The professional identity score of nursing students significantly decreased after the hands-on experience of the cadaver dissection. No significant change in professional identity score was observed in the clinical laboratory science students. However, the effect size (r) was moderate. CONCLUSION: Although professional identity formation fluctuates immediately after the experience of the hands-on experience of a cadaver dissection, the findings do suggest that these hands-on sessions will be effective for developing their professional identity if educational support is provided to help them utilize what they learned through reflection.

Structural Basis for Recognition of Ubiquitylated Nucleosome by Dot1L Methyltransferase.

Histone H3 lysine 79 (H3K79) methylation is enriched on actively transcribed genes, and its misregulation is a hallmark of leukemia. Methylation of H3K79, which resides on the structured disk face of the nucleosome, is mediated by the Dot1L methyltransferase. Dot1L activity is part of a trans-histone crosstalk pathway, requiring prior histone H2B ubiquitylation of lysine 120 (H2BK120ub) for optimal activity. However, the molecular details describing both how Dot1L binds to the nucleosome and why Dot1L is activated by H2BK120 ubiquitylation are unknown. Here, we present the cryoelectron microscopy (cryo-EM) structure of Dot1L bound to a nucleosome reconstituted with site-specifically ubiquitylated H2BK120. The structure reveals that Dot1L engages the nucleosome acidic patch using a variant arginine anchor and occupies a conformation poised for methylation. In this conformation, Dot1L and ubiquitin interact directly through complementary hydrophobic surfaces. This study establishes a path to better understand Dot1L function in normal and leukemia cells.

Euodionosides A-G: megastigmane glucosides from leaves of Euodia meliaefolia.

From a 1-BuOH-soluble fraction of the MeOH extract of leaves of Euodia meliaefolia, collected in Okinawa, seven megastigmane glucosides, named euodionosides A-G, were isolated together with three known megastgmane glucosides, and two aliphatic and three phenolic compounds. Their structures were elucidated through a combination of spectroscopic analyses and application of the modified Mosher's method.

Short-term Heat Exposure Promotes Hippocampal Neurogenesis via Activation of Angiotensin II Type 1 Receptor in Adult Rats.

Angiotensin II (Ang II) synthesized in response to body fluid loss caused by actions such as sweating and breathing is today considered as one of the essential factors for promoting hippocampal neurogenesis. Because heat stimuli, along with exercise, increase systemic levels of Ang II, the effects of short-term heat exposure on hippocampal neurogenesis were examined in adult male rats. When rats were exposed daily to a 1-h heat treatment (36.0 ±â€¯0.1 °C) during a 7-d experimental period, the number of doublecortin-immunoreactive newborn cells in the hippocampal dentate gyrus was increased approximately 1.4-fold compared with that in controls that were exposed to a normothermic environment (25.0 ±â€¯0.8 °C). No significant change was observed in the number of Ki-67-immunoreactive stem cells. Western blot and immunohistochemical analyses revealed an enhancement of vascular endothelial growth factor (VEGF) expression in hippocampal astrocytes following short-term heat exposure. These beneficial effects of short-term heat exposure were prevented when an antagonist for Ang II type 1 receptor (AT1R), candesartan, was given orally. These results indicate that short-term heat exposure enhances adult neurogenesis via activation of AT1R in the hippocampal dentate gyrus, in which VEGF may participate by promoting cell proliferation and/or newborn neuron survival.

Segment-selective absorption of lysozyme in the intestine.

Absorption of fluorescein isothiocyanate-labeled lysozyme (FITC-lysozyme) was examined in rat small intestine. Messenger RNA of megalin, an endocytic receptor for lysozyme in the kidney, was expressed in the lower but not in the upper intestine. In in situ closed loop and recirculation methods, absorption of FITC-lysozyme from the upper intestine was much higher than from the lower intestine. The absorption rate of FITC-lysozyme in the upper intestine was significantly higher than FITC-dextran and was inhibited by unlabeled lysozyme in a concentration-dependent manner. The absorption of FITC-lysozyme was also inhibited by spermine and phenylarsine oxide. These results indicate that the intestinal absorption of lysozyme is segment-selective and occurs preferentially from the upper intestine. Megalin expressed in the lower intestine appears not to have a significant role in the absorption of lysozyme. In the upper intestine, lysozyme appears to be absorbed by an endocytic pathway, and cationic charge may be important for lysozyme absorption.

Affinity of HIV-1 antibody 2G12 with monosaccharides: a theoretical study based on explicit and implicit water models.

In order to develop potential ligands to HIV-1 antibody 2G12 toward HIV-1 vaccine, binding mechanisms of the antibody 2G12 with the glycan ligand of D-mannose and D-fructose were theoretically examined. D-Fructose, whose molecular structure is slightly different from D-mannose, has experimentally shown to have stronger binding affinity to the antibody than that of D-mannose. To clarify the nature of D-fructose's higher binding affinity over D-mannose, we studied interaction between the monosaccharides and the antibody using ab initio fragment molecular orbital (FMO) method considering solvation effect as implicit model (FMO-PCM) as well as explicit water model. The calculated binding free energies of the glycans were qualitatively well consistent with the experimentally reported order of their affinities with the antibody 2G12. In addition, the FMO-PCM calculation elucidated the advantages of D-fructose over D-mannose in the solvation energy as well as the entropic contribution term obtained by MD simulations. The effects of explicit water molecules observed in the X-ray crystal structure were also scrutinized by means of FMO methods. Significant pair interaction energies among D-fructose, amino acids, and water molecules were uncovered, which indicated contributions from the water molecules to the strong binding ability of D-fructose to the antibody 2G12. These FMO calculation results of explicit water model as well as implicit water model indicated that the strong binding of D-fructose over D-mannose was due to the solvation effects on the D-fructose interaction energy.

Systemic angiotensin II and exercise-induced neurogenesis in adult rat hippocampus.

Physical exercise is a robust stimulus that enhances hippocampal neurogenesis via cell proliferation in rodents. We examined the role of systemic angiotensin (Ang) peptides in exercise-dependent enhancement of neurogenesis in the adult rat hippocampus. Plasma angiotensin peptide concentration increased rapidly in response to 30 min of treadmill exercise. After undertaking this exercise once daily for a week, the number of proliferating cells in the hippocampus, identified by 5-bromo-2'-deoxyuridine (BrdU) incorporation, had increased compared with controls. To mimic the increase in plasma Ang peptide concentrations brought about by exercise, rats were injected with 10(-5)M Ang II once daily for a week. The number of BrdU-incorporating cells and of doublecortin (DCX)-expressing immature neurons in the hippocampus rose approximately 1.5 and 1.9-fold compared with controls, respectively. The effects were completely abolished by an Ang II receptor subtype 1 antagonist losartan. These findings, taken together, suggest that an increased concentrations of Ang peptides in the systemic circulation during exercise may promote neurogenesis in the adult rat hippocampus.

Prenylated flavonoid glucoside and two aliphatic alcohol glycosides from the leaves of Euodia meliaefolia (Hance) Benth.

A new prenylated flavonoid (1) and two new aliphatic glycosides (2, 3) have been isolated from leaves of Euodia meliaefolia (Hance) Benth., together with three known compounds, (2R,3R)-5,7,4'-trihydroxy-8-(3-methylbut-2-enyl)dihydroflavonol 7-O-ß-D: -glucopyranoside (phellamurin) (4), (2R,3R)-dihydroquercetin 3'-O-ß-D: -glucopyranoside (5), and (7R,8S)-dihydrodiconiferyl alcohol 4-O-ß-D: -glucopyranoside (6). Their structures were determined on the basis of the results of spectroscopic analysis.

Microtropiosides A-F: ent-Labdane diterpenoid glucosides from the leaves of Microtropis japonica (Celastraceae).

From a 1-BuOH-soluble fraction of a MeOH extract of the leaves of Microtropis japonica, collected in the Okinawa islands, six ent-labdane glucosides, named microtropiosides A-F, were isolated together with one known acyclic sesquiterpene glucoside. Their structures were elucidated by a combination of spectroscopic analyses, and their absolute configurations determined by application of the beta-D-glucopyranosylation-induced shift-trend rule in (13)C NMR spectroscopy and the modified Mosher's method.