Developmental axon branching dramatically increases synaptic capacity and neuronal surface area. Netrin-1 promotes branching and synaptogenesis, but the mechanism by which Netrin-1 stimulates plasma ...membrane expansion is unknown. We demonstrate that SNARE-mediated exocytosis is a prerequisite for axon branching and identify the E3 ubiquitin ligase TRIM9 as a critical catalytic link between Netrin-1 and exocytic SNARE machinery in murine cortical neurons. TRIM9 ligase activity promotes SNARE-mediated vesicle fusion and axon branching in a Netrin-dependent manner. We identified a direct interaction between TRIM9 and the Netrin-1 receptor DCC as well as a Netrin-1-sensitive interaction between TRIM9 and the SNARE component SNAP25. The interaction with SNAP25 negatively regulates SNARE-mediated exocytosis and axon branching in the absence of Netrin-1. Deletion of TRIM9 elevated exocytosis in vitro and increased axon branching in vitro and in vivo. Our data provide a novel model for the spatial regulation of axon branching by Netrin-1, in which localized plasma membrane expansion occurs via TRIM9-dependent regulation of SNARE-mediated vesicle fusion.
While urine has been considered as a useful bio‐fluid for health monitoring, its dynamic changes to physical activity are not well understood. We examined urine's possible antitumor capability in ...response to medium‐level, loading‐driven physical activity. Urine was collected from mice subjected to 5‐minute skeletal loading and human individuals before and after 30‐minute step aerobics. Six cancer cell lines (breast, prostate, and pancreas) and a mouse model of the mammary tumor were employed to evaluate the effect of urine. Compared to urine collected prior to loading, urine collected post‐activity decreased the cellular viability, proliferation, migration, and invasion of tumor cells, as well as tumor weight in the mammary fat pad. Detection of urinary volatile organic compounds and ELISA assays showed that the loading‐conditioned urine reduced cholesterol and elevated dopamine and melatonin. Immunohistochemical fluorescent images presented upregulation of the rate‐limiting enzymes for the production of dopamine and melatonin in the brain. Molecular analysis revealed that the antitumor effect was linked to the reduction in molecular vinculin‐linked molecular force as well as the downregulation of the Lrp5‐CSF1‐CD105 regulatory axis. Notably, the survival rate for the high expression levels of Lrp5, CSF1, and CD105 in tumor tissues was significantly lowered in the Cancer Genome Atlas database. Collectively, this study revealed that 5‐ or 10‐minute loading‐driven physical activity was sufficient to induce the striking antitumor effect by activating the neuronal signaling and repressing cholesterol synthesis. The result supported the dual role of loading‐conditioned urine as a potential tumor suppressor and a source of diagnostic biomarkers.
In biological systems, a few sequence differences diversify the hybridization profile of nucleotides and enable the quantitative control of cellular metabolism in a cooperative manner. In this ...respect, the information required for a better understanding may not be in each nucleotide sequence, but representative information contained among them. Existing methodologies for nucleotide sequence design have been optimized to track the function of the genetic molecule and predict interaction with others. However, there has been no attempt to extract new sequence information to represent their inheritance function. Here, we tried to conceptually reveal the presence of a representative sequence from groups of nucleotides. The combined application of the K-means clustering algorithm and the social network analysis theorem enabled the effective calculation of the representative sequence. First, a "common sequence" is made that has the highest hybridization property to analog sequences. Next, the sequence complementary to the common sequence is designated as a 'representative sequence'. Based on this, we obtained a representative sequence from multiple analog sequences that are 8⁻10-bases long. Their hybridization was empirically tested, which confirmed that the common sequence had the highest hybridization tendency, and the representative sequence better alignment with the analogs compared to a mere complementary.
Nanodiamonds (NDs) with nitrogen vacancy (NV) color centers have the potential for quantum information science and bioimaging due to their stable and non-classical photon emission at room ...temperature. Large-scale fabrication of molecular-size nanodiamonds with sufficient color centers may economically promote their application in versatile multidisciplinary fields. Here, the manufacture of molecular-size NV center-enriched nanodiamonds from graphite powder is reported. We use an ultrafast laser shocking technique to generate intense plasma, which transforms graphite to nanodiamonds under the confinement layer. Molecular dynamics simulations suggest that the high pressure of 35 GPa and the high temperature of 3,000K result in the metaphase transition of graphite to nanodiamonds within 100 ps. A high concentration of NV centers is observed at the optimal laser energy of 3.82 GW/cm2, at which point molecular-size (∼5 nm) nanodiamonds can individually host as many as 100 NV centers. Consecutive melamine annealing following ultrafast laser shocking enriches the number of NV centers >10-fold and enhances the spontaneous decay rate of the NV center by up to 5 times. Our work may enhance the feasibility of nanodiamonds for applications, including quantum information, electromagnetic sensing, bioimaging, and drug delivery.
PURPOSEGroup work is seen as serving multiple positive purposes in health professions education, such as providing an opportunity for students to master course content, transfer knowledge into ...clinical practice, and develop collaborative/teamwork skills. However, there have been relatively few studies exploring medical students’ experiences of the small-group learning context or what they learn in and from that context.
METHODBetween January 2018 and January 2019, the authors used grounded theory methods to conduct semistructured interviews with 9 medical students to explore their perceptions of the value of the group as a mechanism for learning both content and teamwork skills. Sessions were audiorecorded and transcribed verbatim. One author coded the transcripts and identified codes, which the team then discussed, refined, and used to develop themes.
RESULTSStudents were able to express all the expected goals for small-group learning, such as retaining course materials, mimicking future health care team interactions, and creating a collaborative environment. However, when their experiences were further explored, students seemed to have perceived that the value of group learning was as a mechanism for reviewing rather than for deepening their learning. Further, students frequently expressed the opinion that the tutor was the primary factor in the success of a group, and when group function was suboptimal, students described giving up on the group or relying on the tutor to address the problem.
CONCLUSIONSFormal, small-group, tutor-led learning sessions, at least in the context of single-term groups, may not be accomplishing what educators might hope. Although students understand the intent of small-group learning, it cannot be assumed that such groups are deepening learning or solving the teamwork problems in health professions education.
This report describes a method of controlling the sensitivity and reproducibility of a microchip-based immunoassay by using isotachophoresis to preconcentrate the antigen and antibody prior to ...binding. Gel electrophoresis separation is coupled to the preconcentration step to separate the immunocomplex products formed. The system employs a quartz-based LabChip that automates the metering, preconcentration, reaction, separation, and detection. The system also uses a handoff mechanism that switches the immunocomplex from the stacking mode to the separation mode. We show that the handoff timing affects the data quality and repeatability of the electropherograms, and we demonstrate an automatic handoff mechanism to precisely control the signal intensity and separation of peaks of interest. In so doing, the automatic handoff mechanism also improves the reproducibility of the assay. When applied to the homogeneous liquid-phase detection of α-fetoprotein, a common tumor marker, the system shows a greater than 200-fold stacking of specific analytes of interest.
Despite the promise and advantages of autologous cancer cell vaccination, it remains challenging to induce potent anti-tumor immune responses with traditional immunization strategies with whole tumor ...cell lysate. In this study, we sought to develop a simple and effective approach for therapeutic vaccination with autologous whole tumor cell lysate. Endogenous cell membranes harvested from cancer cells were formed into PEGylated nano-vesicles (PEG-NPs). PEG-NPs exhibited good serum stability in vitro and draining efficiency to local lymph nodes upon subcutaneous administration in vivo. Vaccination with PEG-NPs synthesized from murine melanoma cells elicited 3.7-fold greater antigen-specific cytotoxic CD8+ T lymphocyte responses, compared with standard vaccination with freeze-thawed lysate in tumor-bearing mice. Importantly, in combination with anti-programmed death-1 (αPD-1) IgG immunotherapy, PEG-NP vaccination induced 4.2-fold higher frequency of antigen-specific T cell responses (P < 0.0001) and mediated complete tumor regression in 63% of tumor-bearing animals (P < 0.01), compared with FT lysate + αPD-1 treatment that exhibited only 13% response rate. In addition, PEG-NPs + αPD-1 IgG combination immunotherapy protected all survivors against a subsequent tumor cell re-challenge. These results demonstrate a general strategy for eliciting anti-tumor immunity using endogenous cancer cell membranes formulated into stable vaccine nanoparticles.
Tropical rainforests Park, C.C. (Department of Geography, Lancaster University (United Kingdom))
1992, 20020926, 2002-09-26
eBook, Book
First published in 1992. Routledge is an imprint of Taylor & Francis, an informa company.
1. The Tropical Rainforest: History and Environment 2. Destruction of the Rainforest: Rates of Loss 3. Causes ...and Processes of Clearance 4. Impacts and Costs of Destruction 5. Forest Peoples 6. Possible Solutions
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