Innate IFN-γ-Producing Cells in the Spleen of Mice Early after Listeria monocytogenes Infection: Importance of Microenvironment of the Cells Involved in the Production of Innate IFN-γ

Production of innate interferon-γ (IFN-γ) is a crucial step in immunological defense against bacteria. However, there is little information regarding cellular mechanisms underlying IFN-γ production in vivo early after bacterial infection. Here we analyze innate IFN-γ production in the spleen of mice early after Listeria monocytogenes (LM) infection ex vivo by flow-cytometry and in situ by immunohistochemistry, and compare them with the IFN-γ-producing cells reported previously in our in vitro coculture system in which cell-cell interaction between lymphocytes and dying bacterial-infected macrophages is required for the production of IFN-γ. In the spleen at 20 h after LM infection, natural killer (NK) cells, a subset of αβ T cells, and subsets of NKT and γδ T cells produced IFN-γ with features similar to the IFN-γ-producing cells in our in vitro coculture system. Immunohistochemistry revealed that LM bacteria were first phagocytosed mainly by ER-TR9+ marginal zone macrophages (MZMs), then forming infectious foci in close vicinity of the marginal zone (MZ) at 20-h postinfection. At this time point, the IFN-γ-producing cells were accumulating at the same site of infectious foci, around which ER-TR9+ MZMs were clustered but most of bacteria were no longer associated with ER-TR9+ MZMs. These results indicate that innate IFN-γ production by innate lymphocytes takes place at infectious foci formed in close vicinity of the MZ, and they also suggest an important role for the microenvironment of the cells accumulated at infectious foci in inducing the production of innate IFN-γ

A Candidate Active Galactic Nucleus with a Pure Soft Thermal X-ray Spectrum

We report the discovery of a candidate active galactic nucleus (AGN), 2XMM J123103.2+110648 at z = 0.13, with an X-ray spectrum represented purely by soft thermal emission reminiscent of Galactic black hole (BH) binaries in the disk-dominated state. This object was found in the second XMM serendipitous source catalogue as a highly variable X-ray source. In three separate observations, its X-ray spectrum can be represented either by a multicolor disk blackbody model with an inner temperature of kT_in~0.16-0.21 keV or a Wien spectrum Comptonized by an optically thick plasma with kT~0.14-0.18 keV. The soft X-ray luminosity in the 0.5--2 keV band is estimated to be (1.6-3.8)x10^42 erg/s. Hard emission above ~2 keV is not detected. The ratio of the soft to hard emission is the strongest among AGNs observed thus far. Spectra selected in high/low flux time intervals are examined in order to study spectral variability. In the second observation with the highest signal-to-noise ratio, the low energy (below 0.7 keV) spectral regime flattens when the flux is high, while the shape of the high energy part (1-1.7 keV) remains unchanged. This behavior is qualitatively consistent with being caused by strong Comptonization. Both the strong soft excess and spectral change consistent with Comptonization in the X-ray spectrum imply that the Eddington ratio is large, which requires a small BH mass (smaller than ~10^5M_solar.Comment: To Appear in ApJ, 8 pages, 7 figure

企業家精神に影響を与えるマネジメントコントロール・パッケージの解明

2021南山大学企業家精神に影響を与えるマネジメントコントロール・パッケージの解明2018～2021年度科学研究費助成事業 (基盤研究 (C) (一般)) 研究成果報告

Cardio-protective effects of pentraxin 3 produced from bone marrow-derived cells against ischemia/reperfusion injury

AbstractBackgroundInflammation is one of major mechanisms contributing to the pathogenesis of myocardial ischemia/reperfusion (I/R) injury. Pentraxin 3 (PTX3), produced in response to inflammatory signals, acts as a humoral arm of the innate immunity. Here we investigated the role of PTX3 produced from bone marrow-derived cells in myocardial I/R injury using PTX3-deficient (PTX3KO) mice.Methods and resultsPTX3KO mice and wild-type littermate (WT) mice were lethally irradiated and injected with bone marrow (BM) cells, generating four types of mice (WTWT-BM, WTPTX3KO-BM, PTX3KOWT-BM and PTX3KOPTX3KO-BM). Six weeks after BM transplantation, the myocardial I/R procedure (45min of left descending coronary artery ligation followed by 48h of reperfusion) was performed. Infarct size was greater in WT and PTX3KO mice with BM from PTX3KO donor (WTPTX3KO-BM and PTX3KOPTX3KO-BM) compared with WT and PTX3KO mice with BM from WT donor (WTWT-BM and PTX3KOWT-BM). Localization of PTX3 was observed in neutrophils and macrophages in WT and PTX3KO mice with BM from WT donor (WTWT-BM and PTX3KOWT-BM), while only in endothelial cells in WT mice with BM from PTX3KO donor (WTPTX3KO-BM). Infiltration of neutrophils and generation of reactive oxygen species (ROS) at ischemic border zones were greater in PTX3KO mice with BM from PTX3KO donor (PTX3KOPTX3KO-BM) than PTX3KO mice with BM from WT donor (PTX3KOWT-BM). Plasma levels and cardiac expressions of interleukin-6 were higher in PTX3KO mice with BM from PTX3KO donor (PTX3KOPTX3KO-BM) than PTX3KO mice with BM from WT donor (PTX3KOWT-BM). However, no significant differences in infarct size, infiltration of neutrophils, generation of ROS and plasma and cardiac levels of interleukin-6 were observed between WT and PTX3KO mice with BM from WT donor and between WT and PTX3KO mice with BM from PTX3KO donor. These results indicated that the lack of PTX3 produced from BM-derived cells, and not from cardiac resident cells, exacerbated myocardial injury after I/R.ConclusionPTX3 produced from bone marrow-derived cells plays a crucial role in cardiac protection against myocardial I/R injury by attenuating infiltration of neutrophils, generation of ROS and inflammatory cytokine

Actual distribution of bacteriocytes in the trophosome of a beard worm (Oligobrachia mashikoi, Siboglinidae, Annelida): Clarification using whole-mount in situ hybridization

金沢大学環日本海域環境研究センター生物多様性研究部門金沢大学理学部Beard worms (Siboglinidae, Polychaeta) lack a mouth and a digestive tract and harbour chaemosynthetic bacteria in the bacteriocytes of the trophosome. Since beard worms depend on the organic compounds produced by the bacteria for nourishment, the bacteriocytes should be efficient in exchanging various substances with body fluids. For this reason, it is important to determine how the bacteriocytes are organized in the trophosome. As the first step of the present study, the appearance of bacteriocytes was examined in routinely stained paraffin sections. Second, visualization of the actual distribution of the bacteriocytes was attempted using whole-mount in situ hybridization with a probe of the 16S rRNA nucleotide sequence of the bacterium. After routine haematoxylin & eosin staining, the bacteriocytes appeared to be aligned in cell cords accompanied with nutrient-deposit cells that extended from both sides of the trophosome toward the dorsal side and folded up in the coelomic spaces. In whole-mount preparations, however, bacteriocytes with intense signals of 16S rRNA were seen three-dimensionally as many irregular leaves arranged from both sides of the ventral vessel toward the dorsal vessel. We will discuss the physiological significance of this characteristic distribution of the bacteriocytes in the present species. © 2007 The Authors Journal compilation © 2007 The Royal Swedish Academy of Sciences

Active Hippocampal Networks Undergo Spontaneous Synaptic Modification

The brain is self-writable; as the brain voluntarily adapts itself to a changing environment, the neural circuitry rearranges its functional connectivity by referring to its own activity. How the internal activity modifies synaptic weights is largely unknown, however. Here we report that spontaneous activity causes complex reorganization of synaptic connectivity without any external (or artificial) stimuli. Under physiologically relevant ionic conditions, CA3 pyramidal cells in hippocampal slices displayed spontaneous spikes with bistable slow oscillations of membrane potential, alternating between the so-called UP and DOWN states. The generation of slow oscillations did not require fast synaptic transmission, but their patterns were coordinated by local circuit activity. In the course of generating spontaneous activity, individual neurons acquired bidirectional long-lasting synaptic modification. The spontaneous synaptic plasticity depended on a rise in intracellular calcium concentrations of postsynaptic cells, but not on NMDA receptor activity. The direction and amount of the plasticity varied depending on slow oscillation patterns and synapse locations, and thus, they were diverse in a network. Once this global synaptic refinement occurred, the same neurons now displayed different patterns of spontaneous activity, which in turn exhibited different levels of synaptic plasticity. Thus, active networks continuously update their internal states through ongoing synaptic plasticity. With computational simulations, we suggest that with this slow oscillation-induced plasticity, a recurrent network converges on a more specific state, compared to that with spike timing-dependent plasticity alone