A system of antigens expressed at the surface of human red blood cells. Human blood types represented in this group are A,B,AB,or O,depending on which antigen (s),in the form of oligosaccharides,are present at the surface of the erythrocyte membranes. The...[继续阅读]

    A plant hormone,lipid in nature,synthesized in wilting leaves. It counteracts the effects of most other plant hormones by inhibiting cell growth and division,seed germination,and budding. It induces dormancy.一种天然的脂类植物激素,在树叶衰老过程中合成,可以通过抑制细胞生长...[继续阅读]

    Often referred to as optical density. Absorbance is a unit of measure of the amount of light that is absorbed by a solution or by a suspension of bacterial cells.The absorbance is a logarithmic function of the percent of transmission of a particular wavel...[继续阅读]

    1. virology The entry of a virus or viral genome into a host cell after the virus has absorbed to the cell surface. (See ADSORPTION . )2. photometry When light is neither reflected nor transmitted,it is said to be absorbed.Some biological systems can make...[继续阅读]

    The use of a spectrophotometer to determine the ability of solutes to absorb light through a range of specified wavelengths. Every compound has a unique absorption spectrum. An absorption spectrum,which is defined as a plot of the light absorbed versus th...[继续阅读]

    Catalytic antibodies that cleave proteins or carbohydrates at specific residues.They are analogous to restriction enzymes that cleave DNA at specific sequences. Catalytic antibodies have the potential to be used as therapeutic agents,attacking specific vi...[继续阅读]

    A fragment of a chromosome that does not contain a centromere.Because of the absence of a centromere,acentric fragments do not segregate at mitosis and eventually disappear. 缺乏着丝粒的染色体片段。由于缺乏着丝粒,无着丝粒片段在有丝分裂中不分离和最终丢失。...[继续阅读]

    A genus of gram-negative flagella-endowed bacteria that are acid-tolerant aerobic rods. They are also known as the acetic-acid bacteria due to their ability to oxidize ethanol to acetic acid. They are found on fruits and vegetables and can be isolated fro...[继续阅读]

    An organism used in the commercial production of vinegar. When introduced into wine or cider containing 10%-12% alcohol,it will convert to acetic acid. See ACETOBACTER.商业上用于生产醋的一种菌,在含10%-12%乙醇的葡萄酒或苹果酒中,可将乙醇转化为乙酸。参阅Acetobacter。...[继续阅读]

    The anaerobic fermentation of glucose by Clostridium acetobutylicum to form acetone and butanol as end products. At one time,the production of these commercially important chemicals relied on bacterial fermentation,but this has since been replaced by chem...[继续阅读]