(n.) A piece of DNA, usually circular, functioning as part of the genetic material of a cell, not integrated with the chromosome and replicating independently of the chromosome, but transferred, like the chromosome, to subsequent generations. In bacteria, plasmids often carry the genes for antibiotic resistance; they are exploited in genetic engineering as the vehicles for introduction of extraneous DNA into cells, to alter the genetic makeup of the cell. The cells thus altered may produce desirable proteins which are extracted and used; in the case of genetically altered plant cells, the altered cells may grow into complete plants with changed properties, as for example, increased resistance to disease.
Example Sentences:
(1) When micF was cloned into a high-copy-number plasmid it repressed ompF gene expression, whereas when cloned into a low-copy-number plasmid it did not.
(2) These eight large plasmids had indistinguishable EcoRI restriction patterns.
(3) The combined analysis of pathogenesis and genetics associated with the salmonella virulence plasmids may identify new systems of bacterial virulence and the genetic basis for this virulence.
(4) On removal of selective pressure, the His+ phenotype was lost more readily than the Ura+ Trp+ markers, with a corresponding decrease in plasmid copy number.
(5) The data on mapping the episomal plasmid integration sites in yeast chromosomes I, III, IV, V, VII, XV are presented.
(6) A beta-adrenergic receptor cDNA cloned into a eukaryotic expression vector reliably induces high levels of beta-adrenergic receptor expression in 2-12% of COS cell colonies transfected with this plasmid after experimental conditions are optimized.
(7) By hybridization studies, three plasmids in two forms (open circular and supercoiled) were detected in the strain A24.
(8) It should be noted that about a half of the plasmids (11 out of 21) belonged to the incompatibility group P-7 which up to the present time was conditional, since was represented by a single plasmid Rms 148.
(9) Since the plasmid-cured strains did not contain DNA sequences homologous to plasmid DNA, the gene for the free-inclusion protein must be encoded in the chromosome.
(10) A total of 28 cell lines were selected for Geneticin - resistance and inoculated into the footpads of syngeneic animals following co-transfection with pSV2neo and genomic DNA, or transfection with plasmid constructs containing neo and the activated Ha-ras oncogene.
(11) Since resistance is mainly mediated by R plasmids, we undertook to investigate the characteristics of R plasmid-determined beta-lactamase in 6 Gram-negative rods.
(12) The 6.6-kb DNA Bam HI fragment containing the resistance gene was cloned with the plasmid vector pIJ699.
(13) Only one E. coli strain, containing two plasmids that encode endo-pectate lyases, exo-pectate lyase, and endo-polygalacturonase, caused limited maceration.
(14) Plasmids containing the inverted repeat alone bound ER, though less efficiently than did plasmids containing the entire sequence.
(15) The plasmid pMucAMucB, constructed from the Haemophilus influenzae vector pDM2, and a similar plasmid, constructed from pBR322, increased the survival after UV irradiation of Escherichia coli AB1157 with the umu-36 mutation and also caused UV-induced mutation in the E. coli strain.
(16) The 105 000 X g supernatant of the reaction mixture, which contained more than 85% of the thiobarbituric acid-reactive substances, did not inactivate the plasmid DNA.
(17) The remainder of the plasmid appeared to be associated with five positioned nucleosomes and two nonnucleosomal, partially protected regions on the bulk of the molecules.
(18) The fifth plasmid contains sequences which are repeated in the yeast genome, but it is not known whether any or all of the ribosomal protein gene on this clone contains repetitive DNA.
(19) Plasmid profiling was used to distinguish strains of lactobacilli inhabiting the digestive tract of piglets and the feces of sows.
(20) One mutant, BS260, was completely noninvasive on HeLa cells and mapped to a region on the 220-kb virulence plasmid in which we had previously localized several avirulent temperature-regulated operon fusions (A.E.
Protozoa
Definition:
(n. pl.) The lowest of the grand divisions of the animal kingdom.
(pl. ) of Protozoon
Example Sentences:
(1) Many protozoa were in renal tubule cells, endothelial cells and brain.
(2) The 8-, 9-, 10-, and 11-thiastearic acids were found to suppress the synthesis of the cyclopropane-containing fatty acid dihydrosterculic acid (9,10-methyleneoctadecanoic acid) at micromolar concentrations in the growth medium, and all but the 9-thiastearate were found to inhibit the growth of the protozoa at concentrations.
(3) On defaunation of the rumen to remove ciliated protozoa the concentration of phosphatidylcholine in ruminal digesta falls markedly and becomes lower than that in abomasal digesta.
(4) Protozoa were found in 32% of samples (4.6% pathogenic protozoa, 24% facultative pathogenic protozoa and 3.4% apathogenic protozoa).
(5) Omasal contents were collected from slaughtered cattle (n = 54), bison (n = 15), and sheep (n = 40) to determine numbers and generic distribution of ciliated protozoa.
(6) In an attempt to reconstruct the universal ancestor of all present-day tubulin genes the intron positions in 38 different alpha- and beta-tubulin genes from plants, animals, fungi and protozoa were compared.
(7) The drug possesses a strong activity against numerous fungi, some protozoa, and bacteria.
(8) Low GC in Mycoplasma is accompanied by use of UGA for tryptophan and, in ciliated protozoa, by use of UAA and UAG for glutamine.
(9) In addition, a number of antiparasitic agents have been shown to exert their actions through a free radical metabolism: nitro compounds used against trypanosomatids, anaerobic protozoa and helminths; crystal violet used in blood banks to prevent blood transmission of Chagas' disease; the antimalarial primaquine, chloroquinine, and quinhasou; and quinones active in vitro and in vivo against different parasites.
(10) Optimal doses of promastigotes were used which ensured the adaptation of Protozoa in the host's intestine.
(11) In this case the fraction responsible for this transformation contains mainly protozoa.
(12) The apparent production rate of the larger protozoa indicates that they contribute only about 9% of the predicted net microbial protein synthesis in the rumen.
(13) The observation, in parasitic protozoa and helminths, that selfing or non-obligatory mating is a common feature suggests that these processes may be strategies to overcome the cost of meiosis.
(14) Nitroimidazoles have been prepared which show interesting activity against the bacterium, Neisseria gonorrhoeae, in addition to the activities usually shown by nitroimidazoles against protozoa and anaerobic bacteria.
(15) Antigenic macromolecules and some viruses, bacteria, and protozoa enter their apical surface by endocytosis or phagocytosis.
(16) Trapping of many types of small protozoa and manipulation of organelles within protozoa is also possible.
(17) These associations are also compared with other, previously described cases of symbiosis involving prokaryotes and protozoa.
(18) Although C. ventriculi is classified as a holotrich, concentrations of this species in the rumen appear to follow a diurnal cycle more closely related to be entodiniomorph protozoa.
(19) In a later phase, the protozoa treated with histamine or prednisolone died.
(20) The stool samples were examined for the presence of Cryptosporidium sp., other protozoa, helminths, and pathogenic enterobacteria.