厚壳贻贝几丁质提取及几丁质相关基因筛查     

袁俊杰  李迈  唐菊艳  袁孟强  李千千  王晓娜  张美溦  陈伟  王晓通 《海洋通报》2023,(6):686-694

几丁质是贝类贝壳的重要组成成分,在贝壳形成和生物矿化中具有重要作用。本研究通过对厚壳贻贝的贝壳和外套膜边缘三层褶皱进行形态和组织学观察,发现贻贝角质层壳膜是从外褶皱和中褶皱之间的壳膜沟中分泌,而外套膜三层褶皱间组织形态、细胞类型都存在较大差异。此外,本研究还从厚壳贻贝的角质层和贝壳层中提取并鉴定到β-几丁质成分,并构建了外套膜内褶皱（IF）、中褶皱（MF）、外褶皱（OF）的转录组文库,筛查出几丁质合成、降解、结合相关功能的三类几丁质相关基因,对其结构域和表达模式进行进一步分析,发现几丁质合成酶基因以及β氨基己糖苷酶、二-N-乙酰壳二糖酶等几丁质酶基因主要在内、中褶皱表达,而壳三糖苷酶类的几丁质酶基因和几丁质结合蛋白基因则主要在外褶皱表达。在三褶皱差异表达基因的GO富集分析中,进一步发现内、中褶皱主要参与几丁质的生物合成,而外褶皱则主要参与调控几丁质结合、代谢、角质层色素沉着等过程。本研究揭示了外套膜三褶皱在几丁质合成、代谢、结合等功能方面的差异,其中外褶皱可能在厚壳贻贝的贝壳角质层的形成和色素沉着中发挥更重要的作用。本研究有助于了解贻贝贝壳中的几丁质成分以及几丁质相关基因,为软体动物贝...  相似文献   

一种准确而快速的运动目标检测算法   总被引：2，自引：0，他引：2  

曾脉  左志宏  常晓夫  何煊 《成都信息工程学院学报》2008,23(4)

运动目标的检测是计算机视觉和图像编码研究的主要内容,有着广泛的应用领域.减背景法是常用的方法之一,但其受环境光照影响;而帧差法又不能完全提取出目标的所有相关点.针对传统运动目标检测算法的不足,提出基于动态阈值的减背景法与帧差法相结合的运动目标检测算法.实验证明,算法既能完全提取出目标的所有相关点,又适应复杂变化的环境,运动目标检测的精确度和速度都有了明显的提高.  相似文献   

松辽盆地长岭凹陷青山口组一段泥页岩非均质性评价——以吉页油1井为例     

张迈  唐友军  徐兴友  白静  李洪波 《地质与资源》2021,30(3):265-272

泥页岩评价是油气地球化学研究的重要内容,是了解油气资源潜力的基础.以长岭凹陷吉页油1井青一段泥页岩为研究对象,在对其有机质丰度、有机质类型及成熟度等特征分析研究的基础上,结合测井曲线,对其非均质性进行刻画描述和分级评价.得到认识如下:1)泥页岩以Ⅰ型、Ⅱ型干酪根为主,成熟度处于低成熟—成熟阶段;2)建立了非均质性刻画模...  相似文献   

DIETARY PHOSPHORUS REQUIREMENT OF YOUNG ABALONE, HALIOTIS DISCUS HANNAI INO     

Tan Bei-ping  Mai Kang-sen  Liufu Zhi-guo 《中国海洋湖沼学报》2002,20(1):22-31

An experiment was performed to determine the dietary phosphorus requirement of the young abalone,Haliotis discus hannai. Five semi-purified diets were formulated to provide a series of graded levels of dietary total phosphorus (0.23%–1.98) from monobasic potassium phosphate (KH2P04). The brown alga,Laminaria japonica, was used as a control diet. Similar size abalone were distributed in a single-pass, flow-through system using a completely randomized design with six treatments and three replicates each treatment. The abalone were hand-fed to satiation with appropriate diets in excess, once daily at 17:00. The feeding trial was run for 120-d. Survival rate and soft-body to shell ratio (SB/S) were constantly maintained regardless of dietary treatment. However, the weight gain rate (WGR), daily increment in shell length (DISL), muscle RNA to DNA ratio (RNA/DNA), carcass levels of lipid and protein, soft-body alkaline phosphatase (SBAKP), and phosphorus concentrations of whole body (WB) and soft body (SB) were significantly (ANOVA, P<0.05) affected by the dietary phosphorus level. The dietary phosphorus requirements of the abalone were evaluated from the WGR, DISL, and RNA/DNA ratio respectively, by using second-order polynomial regression analysis. Based on these criteria, about 1.0%–1.2% total dietary phosphorus, i.e. 0.9%–1.1% dietary available phosphorus is recommended for the maximum growth of the abalone. Project 39670572 supported by the NSFC.  相似文献   

The U.S. Geophysical Data Center can provide natural hazards damage photographs     

Mai Edwards 《Environmental Geology》1991,18(2):81-81

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Mapping fine-scale population distributions at the building level by integrating multisource geospatial big data     

Yao Yao  Xia Li  Jinbao Zhang  Zhaotang Liang  Ke Mai 《International journal of geographical information science》2017,31(6):1220-1244

Fine-scale population distribution data at the building level play an essential role in numerous fields, for example urban planning and disaster prevention. The rapid technological development of remote sensing (RS) and geographical information system (GIS) in recent decades has benefited numerous population distribution mapping studies. However, most of these studies focused on global population and environmental changes; few considered fine-scale population mapping at the local scale, largely because of a lack of reliable data and models. As geospatial big data booms, Internet-collected volunteered geographic information (VGI) can now be used to solve this problem. This article establishes a novel framework to map urban population distributions at the building scale by integrating multisource geospatial big data, which is essential for the fine-scale mapping of population distributions. First, Baidu points-of-interest (POIs) and real-time Tencent user densities (RTUD) are analyzed by using a random forest algorithm to down-scale the street-level population distribution to the grid level. Then, we design an effective iterative building-population gravity model to map population distributions at the building level. Meanwhile, we introduce a densely inhabited index (DII), generated by the proposed gravity model, which can be used to estimate the degree of residential crowding. According to a comparison with official community-level census data and the results of previous population mapping methods, our method exhibits the best accuracy (Pearson R = .8615, RMSE = 663.3250, p < .0001). The produced fine-scale population map can offer a more thorough understanding of inner city population distributions, which can thus help policy makers optimize the allocation of resources.  相似文献   

Studies on the absorption and utilization of amino acids in the test diets by the prawn Penaeus orientalis     

Mai Kangsen  Li Aijie  Yin Zuofen 《海洋学报(英文版)》1988,7(4):621-629

This experiment was conducted to study the characteristics of absorption of amino acids by different regions of the alimentary tract and the utilization of free amino acids in the test diets of the prawn, Penaeus oricntolis.The midgut gland is the principal site of nutrient absorption. In the foregut, the digestibility coefficient of 15 amino acids tested accounted for 52.5% of the total digestibility coefficient in the entire alimentary tract. In the midgut, the digestibility coefficient was 47.5 % of the total. There was no evidence of the hindgut assimilating amino acids.The free amino acid in the test diet, methionine, was almost absorbed before entering the midgut. Methionine could not be absorbed synchronously with other amino acids bound in the dietary protein, but it did affect the synchronization of other essential amino acids. [3H]-lysine, incorporated into the test diet, was almost totally assimilated within the midgut gland. Five and a half hours after feeding, the labelled amino acid had be  相似文献   

Comparative study on the organoleptic quality of wild and farmed large yellow croaker Larimichthys crocea     

Ma  Rui  Meng  Yuqiong  Zhang  Wenbing  Mai  Kangsen 《中国海洋湖沼学报》2020,38(1):260-274

Journal of Oceanology and Limnology - To fill the blank in systematic study on the organoleptic quality of large yellow croaker Larimichthys crocea, we analyzed the organoleptic quality of the fish...  相似文献   

Effects of vitamin C deficiency or excess on growth performance,anti-oxidative response and fatty acid composition of juvenile abalone Haliotis discus hannai Ino     

Li  Xinxin  Feng  Xiuni  Luo  Kai  Ma  Shuoli  Deng  Junming  Zhang  Wenbing  Mai  Kangsen 《中国海洋湖沼学报》2020,38(6):1936-1944

Journal of Oceanology and Limnology - A 240-day feeding trial was conducted to investigate the effects of dietary vitamin C on growth performance, anti-oxidative response, and fatty acid...  相似文献   

High-resolution simulations for Vietnam - methodology and evaluation of current climate     

Jack Katzfey  Kim Nguyen  John McGregor  Peter Hoffmann  Suppiah Ramasamy  Hiep Van Nguyen  Mai Van Khiem  Thang Van Nguyen  Kien Ba Truong  Thang Van Vu  Hien Thuan Nguyen  Tran Thuc  Doan Ha Phong  Bang Thanh Nguyen  Tan Phan-Van  Trung Nguyen-Quang  Thanh Ngo-Duc  Long Trinh-Tuan 《Asia-Pacific Journal of Atmospheric Sciences》2016,52(2):91-106

To assist the government of Vietnam in its efforts to better understand the impacts of climate change and prioritise its adaptation measures, dynamically downscaled climate change projections were produced across Vietnam. Two Regional Climate Models (RCMs) were used: CSIRO’s variable-resolution Conformal-Cubic Atmospheric Model (CCAM) and the limited-area model Regional Climate Model system version 4.2 (RegCM4.2). First, global CCAM simulations were completed using bias- and variance-corrected sea surface temperatures as well as sea ice concentrations from six Coupled Model Intercomparison Project Phase 5 (CMIP5) global climate models. This approach is different from other downscaling approaches as it does not use any atmospheric fields from the GCMs. The global CCAM simulations were then further downscaled to 10 km using CCAM and to 20 km using RegCM4.2. Evaluations of temperature and precipitation for the current climate (1980-2000) were completed using station data as well as various gridded observational datasets. The RCMs were able to reproduce reasonably well most of the important characteristics of observed spatial patterns and annual cycles of temperature. Average and minimum temperatures were well simulated (biases generally less than 1oC), while maximum temperatures had biases of around 1oC. For precipitation, although the RCMs captured the annual cycle, RegCM4.2 was too dry in Oct.-Nov. (-60% bias), while CCAM was too wet in Dec.- Mar. (130% bias). Both models were too dry in summer and too wet in winter (especially in northern Vietnam). The ability of the ensemble simulations to capture current climate increases confidence in the simulations of future climate.  相似文献