相关实验视频
Updated: Jun 29, 2026

07:36
C. elegans Tracking and Behavioral Measurement
Published on: November 17, 2012
通过共生和自由生活的螺旋体固定
T G Lilburn1, K S Kim, N E Ostrom
1Ribosomal Database Project, Center for Microbial Ecology, Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824-1101, USA.
概括
之前未知能固定的螺旋虫具有酶活性. 这一发现使它们与白的营养和全球循环有关,这可能解释未分配的酶基因.
科学领域:
- 微生物学 微生物学
- 生物化学 生物化学
- 环境科学 环境科学
背景情况:
- 螺旋菌是一种多样化的细菌群,通常在各种环境中发现,包括动物肠道和沉积物.
- 固化,即将大气中的转化为氨,是生命的关键过程.
- 酶基因 (nifH) 是固定能力的关键指标.
研究的目的:
- 为了研究化酶基因同类物和化酶活性在螺旋虫中的存在.
- 确定螺旋虫在营养中的作用,特别是在白中.
- 探索螺旋体固定在全球循环中的影响.
主要方法:
- 从白后和淡水沉积物中选螺旋体基因组,寻找nifH基因同类物.
- 在选择的螺旋体分离物中测定酶活性,包括虫肠道Treponema ZAS-9和Spirochaeta aurantia.
- 在口腔和小动物中分析nifH同类的存在.
主要成果:
- 来自白肠和沉积物的螺旋体被发现具有nifH基因同类物.
- 在这些螺旋体中证明了基酶活性,这对于这个族群来说是一个新的发现.
- 在人类口腔和牛新鲜花三种类型中确定了nifH同类物.
- 在Treponema ZAS-9和Spirochaeta aurantia中确认了15-二固化.
结论:
- 螺旋虫具有固的代谢能力.
- 螺旋虫可能有助于白的营养和全球循环.
- 螺旋体可能是环境样本中以前未被分配的nifH基因的来源.
相关概念视频
Free-falling Bodies: Introduction
All objects, neglecting air resistance, fall with the same acceleration towards the Earth's center due to the force exerted by the Earth's gravity. This experimentally determined fact is unexpected because we are so accustomed to the effects of air resistance and friction that we expect light objects to fall slower than heavier ones. People believed that a heavier object had a greater acceleration when falling until Galileo Galilei (1564–1642) proved otherwise. We now know this is not the case.
Torsional Pendulum
A torsional pendulum involves the oscillation of a rigid body in which the restoring force is provided by the torsion in the string from which the rigid body is suspended. Ideally, the string should be massless; practically, its mass is much smaller than the rigid body's mass and is neglected.
As long as the rigid body's angular displacement is small, its oscillation can be modeled as a linear angular oscillation. The amplitude of the oscillation is an angle. The role of mass is played by the...
As long as the rigid body's angular displacement is small, its oscillation can be modeled as a linear angular oscillation. The amplitude of the oscillation is an angle. The role of mass is played by the...
Self-Locking Screw
A square-threaded screw jack is a mechanical device widely used for lifting heavy loads or applying considerable force. One of the key features that can make a screw jack more effective and reliable is its self-locking capability.
A square-threaded screw jack carrying a load is considered self-locking if the screw retains its position even after the moment applied to it is removed.
A square-threaded screw jack carrying a load is considered self-locking if the screw retains its position even after the moment applied to it is removed.
Rotational Motion about a Fixed Axis
A rigid body's rotation around a fixed axis makes every point within it trace a circular path around a specific line or point. The term given to this type of spinning is defined by the angular position, symbolized by the angle θ. This angle is gauged from a static reference line to the revolving object. From this angular position, any variation is referred to as angular displacement, denoted by dθ. The extent of this displacement can be calculated in degrees, radians, or revolutions, where one...
Torsion of Noncircular Members
Circular shafts undergoing torsional stress maintain their cross-sectional integrity due to their axisymmetric nature. This symmetry ensures an even distribution of stress, allowing the shaft to withstand torsion without distorting. In contrast, square bars, lacking this axial symmetry, experience significant distortion across their cross-sections when subjected to torsion, with the exception of along their diagonals and at lines connecting midpoints. A detailed examination of a cubic element...
Buoyancy and Stability for Submerged and Floating Bodies
In fluid mechanics, buoyancy and stability are key concepts for understanding the behavior of submerged and floating bodies. When a stationary body is fully or partially submerged in a fluid, the fluid exerts a force on the body known as the buoyant force. This force acts vertically upward through a point called the center of buoyancy, which is the center of the displaced fluid volume. According to Archimedes' principle, the magnitude of the buoyant force is equal to the weight of the fluid...

