Crystal structure of tubulin folding cofactor A from Arabidopsis thaliana and its β-tubulin binding characterization

AbstractMicrotubules are composed of polymerized α/β-tubulin heterodimers. Biogenesis of assembly-competent tubulin dimers is a complex multistep process that requires sequential actions of distinct molecular chaperones and cofactors. Tubulin folding cofactor A (TFCA), which captures β-tubulin during the folding pathway, has been identified in many organisms. Here, we report the crystal structure of Arabidopsis thaliana TFC A (KIESEL, KIS), which forms a monomeric three-helix bundle. The functional binding analysis demonstrated that KIS interacts with β-tubulin in plant. Furthermore, mutagenesis studies indicated that the α-helical regions of KIS participate in β-tubulin binding. Unlike the budding yeast TFC A, the two loop regions of KIS are not required for this interaction suggesting a distinct binding mechanism of TFC A to β-tubulin in plants.Structured summaryMINT-7968902, MINT-7968915, MINT-7968951, MINT-7968966: KIS (uniprotkb:O04350) physically interacts (MI:0915) with Tub9 (uniprotkb:P29517) by anti tag coimmunoprecipitation (MI:0007)MINT-7968928: KIS (uniprotkb:O04350) and Tub9 (uniprotkb:P29517) physically interact (MI:0915) by bimolecular fluorescence complementation (MI:0809

Numerical Research on The Nozzle Damping Effect by A Wave Attenuation Method

AbstractNozzle damping is one of the most important factors in the suppression of combustion instability in solid rocket motors. For an engineering solid rocket motor that experiences combustion instability at the end of burning, a wave attenuation method is proposed to assess the nozzle damping characteristics numerically. In this method, a periodic pressure oscillation signal which frequency equals to the first acoustic mode is superimposed on a steady flow at the head end of the chamber. When the pressure oscillation is turned off, the decay rate of the pressure can be used to determine the nozzle attenuation constant. The damping characteristics of three other nozzle geometries are numerically studied with this method under the same operating condition. The results show that the convex nozzle provides more damping than the conical nozzle which in turn provides more damping than the concave nozzle. All the three nozzles have better damping effect than that of basic nozzle geometry. At last, the phase difference in the chamber is analyzed, and the numerical pressure distribution satisfies well with theoretical distribution

The experiences of Chinese general practitioners in communicating with people with type 2 diabetes - a focus group study

BACKGROUND: China has more ascertained cases of diabetes than any other country. Much of the care of people with type 2 diabetes (T2DM) in China is managed by GPs and this will increase with the implementation of health care reforms aimed at strengthening China’s primary health care system. Diabetes care requires effective communication between physicians and patients, yet little is known about this area in China. We aimed to explore the experiences of Chinese GPs in communicating with diabetes patients and how this may relate to communication skills training. METHODS: Focus groups with Chinese GPs were undertaken. Purposive sampling was used to recruit 15 GPs from Guangzhou city in China. All data were audio-recorded and transcribed. A thematic analysis using the Framework Method was applied to code the data and identify themes. RESULTS: Seven males and 8 females from 12 general practices attended 4 focus groups with a mean age of 37.6 years and 7.5 years’ work experience. Four major themes were identified: diversity in diabetic patients, communication with patients, patient-doctor relationship, and communication skills training. GPs reported facing a wide variety of diabetes patients in their daily practice. They believed insufficient knowledge and misunderstanding of diabetes was common among patients. They highlighted several challenges in communicating with diabetes patients, such as insufficient consultation time, poor communication regarding blood glucose monitoring and misunderstanding the risk of complications. They used terms such as “blind spot” or “not on the same channel” to describe gaps in their patients’ understanding of diabetes and its management, and cited this as a cause of ineffective patient-doctor communication. Mutual understanding of diabetes was perceived to be an important factor towards building positive patient-doctor relationships. Although GPs believed communication skills training was necessary, they reported rarely received this. CONCLUSIONS: Chinese GPs reported facing challenges in communicating with diabetes patients. Some of these were perceived as being due to the patients themselves, others were attributed to system constraints, and some were seen as related to a lack of clinician training. The study identified key issues for the development of primary care-based management of diabetes in China, and for developing appropriate communication skills training programs for the primary care workforce. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12875-021-01506-9

Modeling Hidden Nodes Collisions in Wireless Sensor Networks: Analysis Approach

This paper studied both types of collisions. In this paper, we show that advocated solutions for coping with hidden node collisions are unsuitable for sensor networks. We model both types of collisions and derive closed-form formula giving the probability of hidden and visible node collisions. To reduce these collisions, we propose two solutions. The first one based on tuning the carrier sense threshold saves a substantial amount of collisions by reducing the number of hidden nodes. The second one based on adjusting the contention window size is complementary to the first one. It reduces the probability of overlapping transmissions, which reduces both collisions due to hidden and visible nodes. We validate and evaluate the performance of these solutions through simulations

Enhanced sensitivity of neutralizing antibody detection for different AAV serotypes using HeLa cells with overexpressed AAVR

A cell-based transduction inhibition assay (TI) is widely used in clinical trials to detect neutralizing antibody (NAb) titers against recombinant adeno-associated virus (rAAV), one of the most important criteria to exclude patients in gene therapy. Different cell lines are used in cell-based TI because the rAAV transduction efficiencies vary largely among serotypes. A cell line suitable for TI for most serotypes is highly desirable, especially for those with very low transduction efficiencies in vitro such as rAAV8 and rAAV9. Herein, we report an AAVR-HeLa, a stable cell line with overexpressed AAVR, a newly identified receptor for rAAVs, was established for cell-based TIs. The AAVR expression level in AAVR-HeLa cells was approximately 10-fold higher than in HeLa cells, and was stably transfected after twenty three passages. For all AAV serotypes (AAV1-10), except for AAV4, the transduction efficiencies increased significantly in AAVR-HeLa cells. It was demonstrated that the AAVR enhancement of transduction efficiency was only for rAAV and not for lentiviral and adenoviral vectors. According to the minimal multiplicity of infection (MOIs) for the assay, the NAb detection sensitivity increased at least 10 and 20 fold for AAV8 and AAV9, respectively. The seroprevalence of NAbs were investigated at the 1:30 level as a cutoff value using AAVR-HeLa cells. It was shown that the seropositive rate for AAV2 was 87% in serum samples from 99 adults, followed by lower seropositive rates for AAV5 (7%), AAV8 (7%) and AAV9 (1%). Venn diagram analysis showed the presence of cross-reactivity of NAbs to two or three serotypes in 13 samples (13.1%). However, no patient was found to possess NAbs for all the four serotypes. These results demonstrated that the AAVR-HeLa cell line may be utilized to detect the NAbs through cell-based TI assays for most of AAV serotypes

The 18 kDa Translocator Protein (TSPO) Overexpression in Hippocampal Dentate Gyrus Elicits Anxiolytic-Like Effects in a Mouse Model of Post-traumatic Stress Disorder

The translocator protein (18 kDa) (TSPO) recently attracted increasing attention in the pathogenesis of post-traumatic stress disorder (PTSD). This study is testing the hypothesis that the overexpression of TSPO in hippocampus dentate gyrus (DG) could alleviate the anxiogenic-like response in the mice model of PTSD induced by foot-shock. In this study, hippocampal DG overexpression of TSPO significantly reversed the increase of the contextual freezing response, the decrease of the percentage of both entries into and time spent in the open arms in elevated plus maze test and the decrease of the account of crossings from the dark to light compartments in light–dark transition test induced by electric foot-shocks procedure. It was further showed that the behavioral effects of TSPO overexpression were blocked by PK11195, a selective TSPO antagonist. In addition, the expression of TSPO and level of allopregnanolone (Allo) decreased in the mouse model of PTSD, which was blocked by overexpression of TSPO in hippocampal dentate gyrus. The difference of neurogenesis among groups was consistent with the changes of TSPO and Allo, as evidenced by bromodeoxyuridine (BrdU)- positive cells in the hippocampal dentate gyrus. These results firstly suggested that TSPO in hippocampal dentate gyrus could exert a great effect on the occurrence and recovery of PTSD in this animal model, and the anti-PTSD-like effect of hippocampal TSPO over-expression could be at least partially mediated by up-regulation of Allo and subsequent stimulation of the adult hippocampal neurogenesis

Detecting CD20-Rituximab interaction forces using AFM single-molecule force spectroscopy

The invention of atomic force microscopy (AFM) has provided new technology for measuring specific molecular interaction forces. Using AFM single-molecule force spectroscopy (SMFS) techniques, CD20-Rituximab rupture forces were measured on purified CD20 proteins, Raji cells, and lymphoma patient B cells. Rituximab molecules were linked onto AFM tips using AFM probe functionalization technology, and purified CD20 proteins were attached to mica using substrate functionalization technology. Raji cells (a lymphoma cell line) or lymphoma patient cells were immobilized on a glass substrate via electrostatic adsorption and chemical fixation. The topography of the purified CD20 proteins, Raji cells, and patient lymphoma cells was visualized using AFM imaging and the differences in the rupture forces were analyzed and measured. The results showed that the rupture forces between the CD20 proteins on Raji cells and Rituximab were markedly smaller than those for purified CD20 proteins and CD20 proteins on lymphoma patient B cells. These findings provide an effective experimental method for investigating the mechanisms underlying the variable efficacy of Rituximab. © 2011 Science China Press and Springer-Verlag Berlin Heidelberg.Link_to_subscribed_fulltex