【正文】 ucleocaspid(核衣殼) the basic viral structure consisting of a core of nucleic acid surrounded by a protein coat.Spike/peplomer(刺突)is a glycoprotein spike on a viral capsid or viral envelope. These protrusions will only bind to certain receptors on the host cell: they are essential for both host specificity and viral infectivity.Provirus(原病毒)is a virus genome that is integrated into the DNA of a host cell. In the case of bacterial viruses (bacteriophages), provirusesare often referred to as prophages.Prophageis a bacteriophage (often shortened to phage) genome inserted and integrated into the circular bacterial DNA chromosome or existing as an extrachromosomal plasmid. This is a latent form of a phage, in which the viral genes are present in the bacterium without causing disruption of the bacterial cell.Segmented genome(分段基因組) Among RNA viruses and certain DNA viruses, thegenomeis often divided up into separate parts, in which case it is calledsegmented. For RNA viruses, eachsegmentoften codes for only one protein and they are usually found together in one capsid.Retrovirus enveloped viruses that replicate in a host cell through the process of reverse transcription.Temperate phagesare basically bacteriophages which can choose between a lytic and lysogenic pathway of development. The lytic pathway is similar to this of virulentphages. In the lysogenic pathway virus remains dormant(休眠) until induction.Viron capsid of virusViroids the smallest infectious pathogens known, larger only than prions, which are misfolded proteins. Viroids are consisted of solely short strands of circular, singlestranded RNA without protein coats.Virulent phage abacteriophagethat causes the destruction of the host bacterium by lysis. Temperatephages, on the other hand, rarely cause lysis. Satellite (biology) a satellite is a subviral agent posed of nucleic acid that depends on the coinfection of a host cell with a helper or master virus for itsreplication. When a satellite encodes the coat protein in which its nucleic acid is encapsidated it is referred to as a satellite virus.U3Bacillus a genus of Grampositive, rodshaped bacteria and a member of the phylum Firmicutes. Bacillus species can be obligate aerobes, or facultative anaerobes.Capsule a tough sheath or membrane that encloses an organ or other structure in the body, such as a kidney or a synovial joint.Chemotaxis(from chemo + taxis, 趨化性) is the movement of an organism in response to a chemical stimulus. Somatic cells, bacteria, and other singlecell or multicellular organisms direct their movements according to certain chemicals in their environment.Coccus is any bacterium that has a spherical, ovoid, or generally round shape. It is one of the three distinct bacterial shapes, the other two being bacillus and spiralshaped cells.Endospore(芽孢)is a dormant, tough, nonreproductive structure produced by a small number of bacteria from the Firmicute family. The primary function of mostendosporesis to ensure the survival of a bacterium through periods of environmental stress.Fimbria(pluralfimbriae) also referred to as attachment pili by some scientists] is an appendage posed of curlin(渦心) proteins that can be found on many Gramnegative and some Grampositive bacteria that is thinner and shorter than a flagellum.Aflagellumis a whiplike(鞭狀) structure that allows a cell to move. They are found in all three domains of the living world: bacteria, archaea, and eukaryota, also known as protists, plants, animals, and fungi. While all three types offlagellaare used for lootion, they are structurally very different.Gas vacuolesare aggregates of hollow cylindrical structures calledgasvesicles. They are located inside some bacteria . A membrane that is permeable togasbound eachgasvesicle. The inflation and deflation of the vesicles provides buoyancy, allowing the bacterium to float at a desired depth in the water.Glycocalyxa glycoproteinpolysaccharide covering that surrounds the cell membranes of some bacteria, epithelia and other cells. Most animal epithelial cells have a fuzzlike coat on the external surface of their plasma membranes.Inclusion(內(nèi)含物)Lipopolysaccharides, also known as lipoglycans and endotoxins, are large molecules consisting of a lipid and a polysaccharide posed of Oantigen, outer core and inner core joined by a covalent bond。Nucleoid(meaning nucleuslike) is an irregularlyshaped region within the cell of a prokaryote that contains all or most of the genetic material, called genophore(遺傳小片段). In contrast to the nucleus of a eukaryotic cell, it is not surrounded by a nuclear membrane.Peptidoglycan(肽聚糖), also known as murein, is a polymer consisting of sugars and amino acids that forms a meshlike layer outside the plasma membrane of most bacteria, forming the cell wall.Theperiplasm(周質(zhì)空間)is found in gramnegative bacteria and is thespacein between the cytoplasmic and outer membranes. (Many feel aperiplasmis also present in grampositive bacteria in between the cytoplasmic membrane and the peptidoglycan.)Plasmidis a small DNA molecule within a cell that is physically separated from a chromosomal DNA and can replicate independently. They are most monly found in bacteria as small, circular, doublestranded DNA molecules。 however,plasmids are sometimes present in archaea and eukaryotic organisms.Protoplastis a plant, bacterial or fungal cell that had its cell wall pletely or partially removed using either mechanical or enzymatic means.Sex pilus. In bacterial conjugation, an appendage of a male bacterium by which it attaches to a female bacterium, preparatory(準(zhǔn)備的) to the transfer of DNA from male to female.Slayer(surface layer) is a part of thecell envelopemonly found inbacteria, as well as amongarchaea. It consists of a monomolecular layer posed of identicalproteinsorglycoprotein