Major histocompatibility complex genomic investigation of endangered Chinese alligator provides insights into the evolution of tetrapod major histocompatibility complex and survival of critically bottlenecked species

BackgroundThe major histocompatibility complex (MHC) gene family, a vital immune gene family in vertebrates, helps animals defend against pathogens. The polymorphism of MHC genes is important for a species and is considered to be caused by the numerous alleles of MHC antigen-presenting genes. However, the mechanism of this process is unclear due to the lack of data on the MHC structure. The evolutionary trajectories of the tetrapod MHC are also unclear because of insufficient studies on the reptile MHC architecture. Here, we studied the Chinese alligator (Alligator sinensis), which experienced a population bottleneck, but the population increased rapidly in the past 30 years and is proposed to have a unique MHC system to face pathogenic challenges.ResultsWe successfully constructed a 2 Mb MHC region using bacterial artificial chromosome (BAC) library and genome data of the Chinese alligator and checked the antigen-presenting genes using transcriptome data and the rapid amplification of cDNA ends (RACE) technique. The MHC architecture reported here uncovers adjacent Class I and Class II subregions and a unique CD1 subregion. This newly added information suggested that the Class I-II structure pattern was more ancient in tetrapods and helped reconstruct the evolution of the MHC region architecture. We also found multiple groups of MHC class I (MHC-I) (12 duplicated loci, belonging to three groups, two of which were novel) and MHC class II (MHC-II) (11 duplicated loci, belonging to two groups) inside the 2 Mb MHC region, and there were three more duplicated MHC-I loci outside it. These highly duplicated antigen-presenting loci had differences in expression, amino acid length of antigen-presenting exons, and splice signal of exon and intron, which together promoted the polymorphism of duplicated genes. Although the MHC antigen-presenting genes were identified as monomorphic or oligomorphic in our previous population study, the loci with high copy numbers and many differences can make up for this loss, presenting another mechanism for polymorphism in antigen presentation. These MHC-I and MHC-IIB loci with low polymorphism for each locus, but high numbers in all, may also contribute to MHC antigen-presenting binding variability in a population.ConclusionTo summarize, the fine MHC region architecture of reptiles presented in this study completes the evolutionary trajectories of the MHC structure in tetrapods, and these distinctive MHC gene groups in the Chinese alligator may have helped this species to expand rapidly in the past recent years

Effectiveness of Acupuncture for Early Recovery of Bowel Function in Cancer: A Systematic Review and Meta-Analysis

Objectives. The aim of this study was to evaluate the effects of acupuncture therapy to reduce the duration of postoperative ileus (POI) and to enhance bowel function in cancer patients. Methods. A systematic search of electronic databases for studies published from inception until January 2017 was carried out from six databases. Randomized controlled trials (RCTs) involving the use of acupuncture and acupressure for POI and bowel function in cancer patients were identified. Outcomes were extracted from each study and pooled to determine the risk ratio and standardized mean difference. Results. 10 RCTs involving 776 cancer patients were included. Compared with control groups (no acupuncture, sham acupuncture, and other active therapies), acupuncture was associated with shorter time to first flatus and time to first defecation. A subgroup analysis revealed that manual acupuncture was more effective on the time to first flatus and the time to first defecation; electroacupuncture was better in reducing the length of hospital stay. Compared with control groups (sham or no acupressure), acupressure was associated with shorter time to first flatus. However, GRADE approach indicated a low quality of evidence. Conclusions. Acupuncture and acupressure showed large effect size with significantly poor or inferior quality of included trials for enhancing bowel function in cancer patients after surgery. Further well-powered evidence is needed

Spatial and temporal representativeness of point measurements for nitrogen dioxide pollution levels in cities

In many cities around the world the overall air quality is improving, but at the same time nitrogen dioxide (NO2) trends show stagnating values and in many cases could not be reduced below air quality standards recommended by the World Health Organization (WHO). Many large cities have built monitoring stations to continuously measure different air pollutants. While most stations follow defined rules in terms of measurement height and distance to traffic emissions, the question remains of how representative are those point measurements for the city-wide air quality. The question of the spatial coverage of a point measurement is important because it defines the area of influence and coverage of monitoring networks, determines how to assimilate monitoring data into model simulations or compare to satellite data with a coarser resolution, and is essential to assess the impact of the acquired data on public health. In order to answer this question, we combined different measurement data sets consisting of path-averaging remote sensing data and in situ point measurements in stationary and mobile setups from a measurement campaign that took place in Munich, Germany, in June and July 2016. We developed an algorithm to strip temporal from spatial patterns in order to construct a consistent NO2 pollution map for Munich. Continuous long-path differential optical absorption spectroscopy (LP DOAS) measurements were complemented with mobile cavity-enhanced (CE) DOAS, chemiluminescence (CL) and cavity attenuated phase shift (CAPS) instruments and were compared to monitoring stations and satellite data. In order to generate a consistent composite map, the LP DOAS diurnal cycle has been used to normalize for the time of the day dependency of the source patterns, so that spatial and temporal patterns can be analyzed separately. The resulting concentration map visualizes pollution hot spots at traffic junctions and tunnel exits in Munich, providing insights into the strong spatial variations. On the other hand, this database is beneficial to the urban planning and the design of control measures of environment pollution. Directly comparing on-street mobile measurements in the vicinity of monitoring stations resulted in a difference of 48 %. For the extrapolation of the monitoring station data to street level, we determined the influence of the measuring height and distance to the street. We found that a measuring height of 4 m, at which the Munich monitoring stations measure, results in 16 % lower average concentrations than a measuring height of 1.5 m, which is the height of the inlet of our mobile measurements and a typical pedestrian breathing height. The horizontal distance of most stations to the center of the street of about 6 m also results in an average reduction of 13 % compared to street level concentration. A difference of 21 % in the NO2 concentrations remained, which could be an indication that city-wide measurements are needed for capturing the full range and variability of concentrations for assessing pollutant exposure and air quality in cities

High-dimensional frequency conversion in hot atomic system

One of the major difficulties in realizing a high-dimensional frequency converter for conventional optical vortex (COV) stems from the difference in ring diameter of COV modes with different topological charge numbers l. Here, we implement a high-dimensional frequency convertor for perfect optical vortex (POV) modes with invariant size through the four-wave mixing (FWM) process by utilizing Bessel-Gaussian beams instead of Laguerre-Gaussian beams. The measured conversion efficiency from 1530 nm to 795 nm is independent of l at least in subspace of {-6,...,6}, and the achieved conversion fidelities for two-dimensional (2D) superposed POV states exceed 97%. We further realize the frequency conversion of 3D, 5D and 7D superposition states with fidelities as high as 96.70%, 89.16% and 88.68%, respectively. The reported scheme is implemented in hot atomic vapor, it's also compatible with the cold atomic system and may find applications in high-capacity and long-distance quantum communication

Detection of infrared light through stimulated four-wave mixing process

Infrared optical measurement has a wide range of applications in industry and science, but infrared light detectors suffer from high costs and inferior performance than visible light detectors. Four-wave mixing (FWM) process allows detection in the infrared range by detecting correlated visible light. We experimentally investigate the stimulated FWM process in a hot $^{85}$Rb atomic vapor cell, in which a weak infrared signal laser at $1530~$nm induces the FWM process and is amplified and converted into a strong FWM light at $780~$nm, the latter can be detected more easily. We find the optimized single- and two-photon detunings by studying the dependence of the frequency of input laser on the generated FWM light. What's more, the power gain increases rapidly as the signal intensity decreases, which is consistent with our theoretical analysis. As a result, the power gain can reach up to 500 at a signal laser power of $0.1~\mu$W and the number of detected photons increased by a factor of 250. Finally, we experimentally prove that our amplification process can work in a broad band in the frequency domain by exploring the response rate of our stimulated FWM process.Comment: 4 figure

Optical Memory for Arbitrary Perfect Poincar\'e States in an Atomic Ensemble

Inherent spin angular momentum (SAM) and orbital angular momentum (OAM) which manifest as polarization and spatial degrees of freedom (DOF) of photons, hold a promise of large capability for applications in classical and quantum information processing. To enable these photonic spin and orbital dynamic properties strongly coupled with each other, Poincar\'{e} states have been proposed and offer advantages in data multiplexing, information encryption, precision metrology, and quantum memory. However, since the transverse size of Laguerre Gaussian beams strongly depends on their topological charge numbers $\left| l \right|$, it is difficult to store asymmetric Poincar\'{e} states due to the significantly different light-matter interaction for distinct spatial modes. Here, we experimentally realize the storage of perfect Poincar\'{e} states with arbitrary OAM quanta using the perfect optical vortex, in which 121 arbitrarily-selected perfect Poincar\'{e} states have been stored with high fidelity. The reported work has great prospects in optical communication and quantum networks for dramatically increased encoding flexibility of information

Oncogenic potential of truncated RXRα during colitis-associated colorectal tumorigenesis by promoting IL-6-STAT3 signaling

我国每年新发结直肠癌的临床病人约有30多万人，居肿瘤类第三位，其发病率与死亡率均为世界平均水平的2倍以上。张晓坤教授课题组自主研发的靶向抗癌药物分子K-80003已于2016年12月30日获得美国FDA的临床试验许可批件，正式进入新药上市前的临床人体试验阶段，正在晚期结直肠癌患者中开展临床测试。这一发现的原始创新性十分突出，兼具抗癌“新机理”、“新靶点”和“新药物分子结构的发现、阐明和开发”三大创新点于一体，可以说是我国首例从源头开始的抗癌药物自主研发。此次课题组成功构建了tRXRα转基因小鼠，阐述了tRXRα促进肿瘤发生发展的功能及机制，及其作为治疗结肠癌靶点的可行性及特异性。这一研究也进一步阐明了K-80003分子具有特异高效的抑瘤作用。 厦门大学药学院博士生叶晓红和吴华为论文的共同第一作者，张晓坤教授为通讯作者。【Abstract】Retinoid X receptor-alpha (RXRα) is a potent regulator of inflammatory responses; however, its therapeutic potential for inflammatory cancer remains to be explored. We previously discovered that RXRα is abnormally cleaved in tumor cells and tissues, producing a truncated RXRα (tRXRα). Here, we show that transgenic expression of tRXRα in mice accelerates the development of colitis-associated colon cancer (CAC). The tumorigenic effect of tRXRα is primarily dependent on its expression in myeloid cells, which results in interleukin-6 (IL-6) induction and STAT3 activation. Mechanistic studies reveal an extensive interaction between tRXRα and TRAF6 in the cytoplasm of macrophages, leading to TRAF6 ubiquitination and subsequent activation of the NF-κB inflammatory pathway. K-80003, a tRXRα modulator derived from nonsteroidal anti-inflammatory drug (NSAID) sulindac, suppresses the growth of tRXRα-mediated colorectal tumor by inhibiting the NF-κB-IL-6-STAT3 signaling cascade. These results provide new insight into tRXRα action and identify a promising tRXRα ligand for treating CAC.We thank Professor Jianming Li from Soochow University for technical assistance. This work was partially supported by grants from the Natural Science Foundation of China (81672749, U1405229, 81741171, 91429306), National Institute of Health (RO1 CA198982), Regional Demonstration of Marine Economy Innovative Development Project (16PYY007SF17), Fujian Provincial Science & Technology Department (2017YZ0002), and the National Institute of Health (R01CA198982). 该研究工作获得了国家自然科学基金委、教育部、福建省科技厅、厦门市科技计划项目的经费支持