The role of histones and histone modifying enzymes in ribosomal dna silencing in saccharomyces cerevisiae

In S. cerevisiae, the ribosomal DNA locus is silent for RNA polymerase II (Pol II) transcription and recombination (rDNA silencing). Our goal is to understand how histones and histone-modifying enzymes regulate the silent chromatin at the rDNA locus. Sir2, a NAD+-dependent histone deacetylase, is required for rDNA silencing. To understand how Sir2 regulates rDNA silencing, we performed chromatin immunoprecipitation to measure the association of modified histones across the rDNA repeat in wild-type and sir2Δ cells. We found that in sir2Δ cells, histone H3 at the rDNA became hyperacetylated and hypermethylated. High levels of K4-methylated H3 correlate with Pol II transcription. Consistent with this, we found that the nontranscribed spacer (NTS) region was transcribed by Pol II in sir2Δ cells. To investigate if transcription of the NTS region regulates rDNA silencing, we overexpressed this region both in trans and in cis. Our data showed that overexpression of the NTS region in cis caused Pol II silencing defect and hyperrecombination at the rDNA. These data suggest that Sir2 contributes to maintain the silent chromatin at the rDNA by repressing Pol II transcription in the NTS region. We also found that the NTS transcripts could be translated in vitro and that they copurified with polysomes, suggesting that the transcripts may encode proteins or that the transcripts are somehow involved in the process of translation. Additionally, we examined the role of linker histone H1 in regulating rDNA silencing. We found that, unlike Sir2 that represses both Pol II transcription and recombination, histone H1 only represses recombination at the rDNA. The hyperrecombination defect at the rDNA is more severe in sir2Δ hho1Δ double mutant than in either single mutant, suggesting histone H1 and Sir2 act independently. Consistently, hho1Δ cells did not accumulate extrachromosomal rDNA circles (ERCs) or the Holliday junction intermediates, which accumulate in sir2Δ cells. These data suggest that histone H1 and Sir2 regulate different recombination pathways. In summary, my research has provided insight into the mechanism of how silent chromatin at the rDNA locus is regulated, which will help us understand how fundamental components of chromosomes affect gene expression and genome stability

Construction of Trust Relationship between Doctors and Patients: A Social Psychological Analysis

Doctor-patient trust is the basis of harmonious doctor-patient relationship. Social psychology plays a unique role in interpreting the connotation and construction of doctor-patient trust relationship. From the two levels of doctor-patient interpersonal trust and intergroup trust, this paper summarizes the relevant theoretical viewpoints of social psychology on the construction of doctor-patient trust relationship, and analyzes the key factors affecting doctor-patient interpersonal trust and intergroup trust. On this basis, this paper puts forward the construction path of doctor-patient trust of “interpersonal interaction-emotional communication-interpersonal trust” and “intergroup interaction-social knowledge-intergroup trust”, reveals the interaction mechanism of interpersonal trust and intergroup trust and the circular feedback mechanism between them to promote the formation of doctor-patient trust relationship, and establishes a social psychology model of the formation mechanism of doctor-patient trust relationship

Formation-maintaining control strategy for InSAR satellite

The control accuracy of distributed interferometric synthetic aperture radar satellite formation configuration maintenance is one of the key factors affecting the baseline length and thus the elevation measurement accuracy. According to the description and analysis of the relative orbital elements of formation dynamics, an unbiased four-pulse formation maintenance control method with independent in-plane and out-of-plane control is optimized and designed based on the traditional pulse control scheme. In particular, the coupling influence between relative orbital roots in the control process is compensated by combining with engineering practice, also the corresponding control strategy is formulated. The method has been applied to TH-2 system, and the correctness of the method has been proved by ground simulation and in-orbit data, so as to effectively ensure the expected distribution of interference baseline and provide guarantee for the smooth development of land elevation survey task

An engineering optimization method for distributed spaceborne InSAR formation configuration based on multiple constraints

The formation configuration design of the distributed spaceborne interferometric SAR is the key issue affects the DEM system performance. Combined with the practical engineering of TH-2 satellite, an optimal method of InSAR formation determination based on multi-engineering constraints is proposed. The relative movement of formation is introduced firstly, and the mathematical description of the engineering bounds is modeled; then by using an improved ant colony algorithm, the parameters of formation are finally achieved with safety function maximization. Through the simulation, it is proved that the formation obtained can not only meets all the constraints, but also has the passive safety. Moreover, the correctness and validity of this method has already been verified in the on-orbit experiments

Utilization of BIM in the construction of a submarine tunnel: a case study in Xiamen city, China

Building information modeling (BIM) is an emerging technology that can effectively solve the problems of information dispersion, complex personnel management, and lack of construction supervision, which often occur during the construction of tunnel engineering. Taking the construction of Haicang Tunnel in Xiamen, China as a case study, the utilization of BIM technology in the design stage, the construction simulation and operation are demonstrated during the full-life cycle of the project. During the construction of Haicang Tunnel, the technologies of BIM 3D, BIM 4D, BIM 5D, and Cloud Platform are used to make the construction process controllable and to facilitate the implementation and deployment of construction plans. BIM 3D is a visualization method to show the detailed model in the construction. The design is optimized by the navigation collision function of BIM 3D. BIM 4D adds the time schedule into BIM 3D model to show the construction schedule. BIM 5D adds the cost into BIM 4D model to show the construction consumption. The methods of BIM 4D and BIM 5D can assist the engineering management in allocating resources and funds in the project. Cloud Platform is used to effectively implement information management

Effects of plant diversity and big-sized trees on ecosystem function in a tropical montane evergreen broad-leaved forest

IntroductionScale dependencies play a vital role in defining the biodiversity-ecosystem functioning relationship in forest ecosystems, which varies based on the magnitude of multiple plant diversity attributes, soil properties, and aboveground biomass in forest ecosystems. However, the effects of plant diversity and big-sized trees on the relationship between plant diversity and aboveground biomass across different scales remain unclear in forest ecosystems.MethodsBased on a 30-ha tropical montane evergreen broad-leaved forest dynamics plot in Yunnan province, China, we comparatively analyzed the importance of scale-dependent effects of multiple plant diversity attributes, soil properties, neighborhood competition intensity and aboveground biomass of big-sized trees, as well as stand structural complexity on aboveground biomass of all woody individuals. The aim is therefore to identify the main predictors for sustaining aboveground biomass of all woody individuals, considering multiple biotic and abiotic factors jointly, as well as underlying mechanisms.ResultsOur results suggest that indicators such as species richness and phylogenetic diversity did not strongly contribute to aboveground biomass of all woody individuals with increasing spatial scales, while aboveground biomass of big-sized trees exhibited the greatest contribution to aboveground biomass of all woody individuals. Stand structural complexity, characterized by variances in woody plant diameter at breast height, also contributed more to aboveground biomass of all woody individuals indirectly via neighborhood competition intensity and aboveground biomass of big-sized trees. Contributions of functional dispersion and community-weighted mean of leaf phosphorus concentration to aboveground biomass of all woody individuals became stronger with increasing spatial scales. Neighborhood competition intensity exhibited a negative linear relationship with aboveground biomass of all woody individuals at the smallest scale, but it affected positively aboveground biomass of all woody individuals across spatial scales, likely due to indirect effects via aboveground biomass of big-sized trees.DiscussionBig-sized trees will likely become more important in biodiversity maintenance and ecosystem function management as deforestation and forest degradation

An Increase in Mitochondrial DNA Promotes Nuclear DNA Replication in Yeast

Coordination between cellular metabolism and DNA replication determines when cells initiate division. It has been assumed that metabolism only plays a permissive role in cell division. While blocking metabolism arrests cell division, it is not known whether an up-regulation of metabolic reactions accelerates cell cycle transitions. Here, we show that increasing the amount of mitochondrial DNA accelerates overall cell proliferation and promotes nuclear DNA replication, in a nutrient-dependent manner. The Sir2p NAD+-dependent de-acetylase antagonizes this mitochondrial role. We found that cells with increased mitochondrial DNA have reduced Sir2p levels bound at origins of DNA replication in the nucleus, accompanied with increased levels of K9, K14-acetylated histone H3 at those origins. Our results demonstrate an active role of mitochondrial processes in the control of cell division. They also suggest that cellular metabolism may impact on chromatin modifications to regulate the activity of origins of DNA replication

Pharmacokinetics/pharmacodynamics of beta-lactams alone and in combination with beta-lactamase inhibitors against beta-lactamase-inducible Pseudomonas aeruginosa

The pharmacokinetics and antimicrobial efficacies of β-lactams alone and in combination with β-lactamase inhibitors were investigated applying a rabbit tissue cage model against a strain of AmpC β-lactamase inducible Pseudomonas aeruginosa (PSA246). Two sterilized golf wiffle balls were surgically implanted in the rabbit dorsal cervical area. After 4 weeks, wiffle balls were filled with tissue cage fluid (TCF), in which 2-ml of 10 6 CFU/ml of the test isolate were inoculated. To achieve the same T \u3e MIC as in humans, 400 mg/kg of the β-lactams alone and in combination with the inhibitors were administrated b.i.d. via subcutaneous injection. The dose regimens were as follows: piperacillin alone, the combination of piperacillin (4-g)-tazobactam (0.5-g), ticarcillin alone, the combination of ticarcillin (3-g)-clavulanate (0.1-g), and the combination of ticarcillin (3-g) - clavulanate (0.3-g). The pharmacokinetics of the drugs in serum and TCF were evaluated, there were no impact of tazobactam and clavulanate on the absorption, tissue penetration and elimination of piperacillin and ticarcillin. Tazobactam significantly enhanced the antimicrobial activity of piperacillin against the strain of AmpC β-lactamase inducible P. aeruginosa . No AmpC induction by tazobactam was observed in vitro and in vivo. The antibacterial activity of ticarcillin was synergised by clavulanate at low dose, but clavulanate at high dose had no impact on ticarcillin. AmpC induction by high dose clavulanate was observed in rabbit TCF, which was confirmed by the in vitro induction study. The results of the present study indicate that bacterial resistance could be developed due to AmpC in vivo induction by clavulanate. Consequently, to ensure the successful therapy for P. aeruginosa infected patients, the combination of piperacillin and tazobactam should be used, instead of the combination of ticarcillin and clavulanate.

Effect of Sisal Fiber Surface Treatment on Properties of Sisal Fiber Reinforced Polylactide Composites

Mechanical properties of composites are strongly influenced by the quality of the fiber/matrix interface. The objective of this study was to evaluate the mechanical properties of polylactide (PLA) composites as a function of modification of sisal fiber with two different macromolecular coupling agents. Sisal fiber reinforced polylactide composites were prepared by injection molding, and the properties of composites were studied by static/dynamic mechanical analysis (DMA). The results from mechanical testing revealed that surface-treated sisal fiber reinforced composite offered superior mechanical properties compared to untreated fiber reinforced polylactide composite, which indicated that better adhesion between sisal fiber and PLA matrix was achieved. Scanning electron microscopy (SEM) investigations also showed that surface modifications improved the adhesion of the sisal fiber/polylactide matrix

Security Development Path for Industrial Internet Supply Chain

 Industrial Internet security is crucial for strengthening the manufacturing and network sectors of China. Deep learning, owing to its strong expression ability, good adaptability, and high portability, can support the establishment of an intelligent and autonomous industrial Internet security system and method. Therefore, it is of great value to promote the integrated innovation of deep learning and industrial Internet security. In this study, we analyze the development demand for industrial Internet security from the perspective of macro industrial environment, security technology, and deep learning system, and summarize the application status of deep learning to industrial Internet security in terms of device, control, network, application, and data layers. The security challenges faced by deep learning application to industrial Internet primarily lie in model training and prediction. Furthermore, we identify key research directions including interpretability of deep neural networks, cost control of sample collection and calculation, imbalance of sample sets, reliability of model results, and tradeoff between availability and security. Finally, some suggestions are proposed: A dynamic defense system in depth should be established in terms of overall security strategy; an application-driven and frontier exploration integrated method should be adopted to achieve breakthroughs regarding key technologies; and resources input should be raised for such interdisciplinary fields to establish an industry–university–research institute joint research ecosystem