罗氏沼虾线粒体锰超氧化物歧化酶的克隆表达与功能研究     

李亚男  陆霖青  张鹏  秦真东  林蠡  晏磊 《热带海洋学报》2022,41(3):111-118

罗氏沼虾(Macrobrachium rosenbergii)是我国重要的经济虾类之一。近年来, 细菌性感染造成罗氏沼虾养殖业病害频发, 经济损失巨大。因此了解其免疫机制对于指导疾病防控至关重要。线粒体锰超氧化物歧化酶(mitochondrial manganese superoxide dismutase, mMnSOD)被认为是抵御氧化应激的第一道防线, 在先天性免疫中具有至关重要的作用。目前, 甲壳动物中mMnSOD的免疫功能尚不清楚。为此, 本研究克隆了罗氏沼虾mMnSOD基因(mMnSOD of M. rosenbergii, MrmMnSOD), 制备了多克隆抗体, 分析了嗜水气单胞菌(Aeromonas hydrophila)感染下, MrmMnSOD在不同组织中的表达模式。结果显示, 肝胰腺和肠组织中MrmMnSOD的基因表达水平分别在感染后3h和6h达到最大; 组织免疫荧光分析显示, 肝胰腺和肠组织中MrmMnSOD均在感染后12h达到最大荧光强度。以上结果表明, mMnSOD参与了罗氏沼虾对嗜水气单胞菌的免疫应激反应。进一步的蛋白抑菌实验表明, MrmMnSOD可显著抑制大肠杆菌(Escherichia coli)、嗜水气单胞菌、副溶血弧菌(Vibrio parahaemolyticus)、金黄色葡萄球菌(Staphylococcus aureus)和无乳链球菌(Streptococcus agalactiae)的生长, 推测该蛋白可能属于免疫相关分子, 可通过抑菌反应发挥免疫功能。当前的研究结果进一步丰富了甲壳动物先天性免疫基础理论, 也可为今后罗氏沼虾的病害防控和药物研发提供新的靶点参考。  相似文献   

Oort Cloud Comet Perihelion Asymmetries: Galactic Tide, Shower or Observational Bias?     

John J. Matese  Patrick G. Whitman  Daniel P. Whitmire 《Celestial Mechanics and Dynamical Astronomy》1997,69(1-2):77-87

We investigate the distribution of Oort cloud comet perihelia. The data considered includes comets having orbital elements of the two highest quality classes with original energies designated as new or young. Perihelion directions are determined in galactic, ecliptic and geocentric equatorial coordinates. Asymmetries are detected in the scatter and are studied statistically for evidence of adiabatic galactic tidal dynamics, an impulse-induced shower and observational bias. The only bias detected is the well-known deficiency of observations with perihelion distances q > 2.5 AU. There is no significant evidence of a seasonal dependence. Nor is there a substantive hemispherical bias in either ecliptic or equatorial coordinates. There is evidence for a weak stellar shower previously detected by Biermann which accounts for ≈ 10% of the total observations. Both the q bias and the Biermann star track serve to weaken the evidence for a galactic tidal imprint. Nevertheless, statistically significant asymmetries in galactic latitude and longitude of perihelia remain. A latitude asymmetry is produced by a dominant tidal component perpendicular to the galactic disk. The longitude signal implies that ≈ 20% of new comets need an additional dynamical mechanism. Known disk non-uniformities and an hypothetical bound perturber are discussed as potential explanations. We conclude that the detected dynamical signature of the galactic tide is real and is not an artifact of observational bias, impulsive showers or poor data. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

The genotoxic effects of benzo[a]pyrene and methamidophos on black porgy evaluated by comet assay     

刘日先洪华生  王新红王克坚 王春光 《中国海洋湖沼学报》2005,23(4):455-460

In this study, two common pollutants （benzo[a]pyrene and methamidophos） in marine environment were tested by comet assay for their inducement of in vivo genotoxic effect to the blood cells of black porgy （ Acanthopagrus schlegeli）. The fish was exposed to 2 μg/L of benzo[a]pyrene （BaP） and methamidophos, and their mixture. The assay was performed on whole blood at 2 h, 5 h, 24 h and 96 h exposure intervals. A significant increase in DNA damage was observed in each treatment with the pollutants. Additive effect of BaP and methamidophos was also found in the experiment. However, the decrease ratios of DNA damage for 5 h and 96 h exposure interals compared with 2 h and 24 h exposure ones, respectively, were noticed. This phenomenon may be explained by the function of repairing process via enzyme cytochrome P450 in the animal. Evidence of the genotoxicity of organophosphorus pesticides （OPs） and polynuclear aromatic hydrocarbons （PAHs） on marine fish are discussed in this paper.  相似文献   

C/199501(Hale-Bopp)彗星的观测和轨道计算     

《天文学报》1997,(4)

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哈雷彗星主尾流的研究     

赵海斌  胡中为  王建中  侯振宇 《天文学报》2002,43(1):66-74

哈雷彗星在日彗距较大时出现长而直的主彗尾（尾流），这是很有趣的。尾流一般是指等离子体尾流；但是，当地球接近彗星轨道面时，尘埃尾流可能叠加到主彗尾上。在一般感光波段宽的彗星底片上很难区分这两种尾流。本文选取哈雷彗星在不同日彗距的5条主尾流，作了光度测量和比较分析。得出沿各尾轴及其垂直方向几个截面的亮度分布、亮度半极大全宽、尾轴的视风差角和真风差角及彗尾长度。在所分析的蓝敏底片上，过近日点前的2个尾流肯定是等离子体尾流，而5个尾流的相似性以及其他证据说明它们主要都是等离子体尾流，尘埃彗尾的污染是次要的。  相似文献   

Optical Spectroscopy of Comet C/2000 WM1 (LINEAR) at the Guillermo Harro Astrophysical Observatory in Mexico     

Churyumov  Klim I.  Luk'yanyk  Igor V.  Berezhnoi  Alexei A.  Chavushyan  Vahram H.  Sandoval  Lourdes S.  Palma  Alejandro A. 《Earth, Moon, and Planets》2002,90(1-4):361-368

We present a preliminary analysis of medium resolution optical spectra of comet C/2000 WM1 (LINEAR) obtained on 22 November 2001. Theemission lines of the molecules C₂, C₃, CN, NH₂,H₂O⁺ and presumably CO (Asundi and triplet bands) and C₂ ^-were identified in these spectra. By analysing the brightnessdistributions of the C₂, C₃, CN emission lines along theslit of the spectrograph we determined some physical parameters of theseneutrals, such as their lifetimes and expansion velocities inthe coma. The Franck–Condon factors for the CO Asundi bands and C₂ ^- bands were calculated using a Morse potential model.  相似文献   

哈雷彗星Ⅰ型彗尾风差角的测定     

胡中为  赵建洪 《中国天文和天体物理学报》1989,(1)

1986年3月8日哈雷彗星发生一次Ⅰ型彗尾断尾事件,新主尾与老主尾的风差角不同。本文对我们所摄哈雷彗星大尺度底片,用光度测量方法定出主尾轴的视风差角;并且用导出的公式,算出相应的真风差角。最后,对所得结果进行一些讨论。  相似文献   

The Influence of Reactive Torques on Comet Nucleus Rotation     

A. I. Neishtadt  D. J. Scheeres  V. V. Sidorenko  P. J. Stooke  A. A. Vasiliev 《Celestial Mechanics and Dynamical Astronomy》2003,86(3):249-275

Reactive torques, due to anisotropic sublimation on a comet nucleus surface, produce slow variations of its rotation. In this paper the secular effects of this sublimation are studied. The general rotational equations of motion are averaged over unperturbed fast rotation around the mass center (Euler-Poinsot motion) and over the orbital comet motion. We discuss the parameters that define typical properties of the rotational evolution and discover different classifications of the rotational evolution. As an example we discuss some possible scenarios of rotational evolution for the nuclei of the comets Halley and Borrelly.  相似文献   

Collective resonant phenomena on small bodies in the solar system     

Ch. Froeschlé  C. Froeschlé 《Celestial Mechanics and Dynamical Astronomy》1992,54(1-3):71-89

For both asteroids and meteor streams, and also for comets, resonances play a major role for their orbital evolutions but on different time scales. For asteroids both mean motion resonances and secular resonances not only structure the phase space of regular orbits but are mainly at the origin for the inherent chaos of planet crosser objects.For comets and their chaotic routes temporary trapping into orbital resonances is a well known phenomenon. In addition for slow diffusion through the Kuiper belt resonances are the only candidates for originating a slow chaos.Like for asteroids, resonances with Jupiter play a major role for the orbital evolution of meteor streams. Crossing of separatrix like zones appears to be crucial for the formation of arcs and for the dissolution of streams. In particular the orbital inclination of a meteor stream appears to be a critical parameter for arc formation. Numerical results obtained in an other context show that the competition between the Poynting-Robertson drag and the gravitational interaction of grains near the 2/1 resonance might be very important in the long run for the structure of meteor streams.  相似文献   

Hg对锦州湾表层沉积物异养细菌代谢酶活性的影响研究     

徐庆彤  刘瑞志  郭小雅  李捷  雷坤  刘庆庆  郝晨林 《海洋科学》2017,41(8):108-115

为了解重金属Hg对锦州湾海域表层沉积物中异养细菌的主要代谢酶的影响,采用Hakanson潜在生态危害指数法对锦州湾表层沉积物中重金属Hg开展潜在生态风险评价,利用平板扩散法测定了9个站位沉积物中异养细菌四种水解酶活性。结果显示:锦州湾海域表层沉积物中重金属污染严重,Hg的含量和潜在生态危害河口最为严重,向外逐步递减,表明本海域表层沉积物中的Hg主要由陆源输入;表层沉积物中异养细菌水解酶活性与抗性异养菌比例均表现为西南部河口区高于东北部外海海域,与重金属Hg的含量分布及Hakanson潜在生态危害指数基本相似,这表明长期高浓度的重金属污染,改变了锦州湾海域表层沉积物中的异养菌的生理代谢过程,在生理或遗传物质上对重金属产生了一定的抗性;磷酸酶、蛋白酶、脂肪酶与沉积物中Hg的含量具有显著正相关性,说明其对重金属Hg较为敏感,在一定程度上可作为反映锦州湾海域沉积物中重金属Hg污染状况的生物学指标。  相似文献