Ribonucleic acids inhibition

Extracts from 152 plant species, representing 46 different families, were screened for effects on tobacco mosaic virus (TMV) replication in cucumber cotyledons. Twenty species have shown enough activity to warrant further study. Several members of the Caprifoliaceae family increased virus replication. An extract of Lonicera involucrata enlarged the virus lesions in local lesion hosts and produced a thirty fold increase in virus titer, but had no effect on virus replication in systemic hosts. The active material appears to affect the virus defense mechanism of local lesion hosts. An extract of common geranium is an active virus inhibitor. It inactivates TMV and TMV-RNA (ribonucleic acid) in vitro by forming non-infectious complexes. In vivo, it also inhibited starch lesion formation in cucumber cotyledons incited by TMV infection. 

Female NMRI mice were exposed to 100 ppm of hydrogen sulfide for 2 hours at 4-day intervals excitement was observed (Savolainen et al. 1980). Exposure also resulted in decreased cerebral ribonucleic acid (RNA), decreased orotic acid incorporation into the RNA fraction, and inhibition of cytochrome oxidase. An increase in the glial enzyme marker, 2, 3 -cyclic nucleotide-3 -phosphohydrolase, was seen. Neurochemical effects have been reported in other studies. Decreased leucine uptake and acid proteinase activity in the brain were observed in mice exposed to 100 ppm hydrogen sulfide for 2 hours (Elovaara et al. 1978). Inhibition of brain cytochrome oxidase and a decrease in orotic acid uptake were observed in mice exposed to 100 ppm hydrogen sulfide for up to 4 days (Savolainen et al. 1980). 

Rifaximin is a synthetic rifamycin derivative, which acts by inhibiting bacterial ribonucleic acid (RNA) synthesis [48]. It is virtually unabsorbed after oral administration and is, therefore, used primarily to treat gastrointestinal infections. Rifaximin possesses a broad spectrum of antimicrobial activity, covering Gram-positive and Gram-negative bacteria, both arerobic and anaerobic [49], Several studies [44, 49-62] have shown that in patients with HE rifaximin displays an efficacy similar to that of lactulose and neomycin (table 1). A recently published study [62] compared the efficacy and safety of... 

Drug X is an ami mycobacterial agent that inhibits other bacteria as well as poxviruses. However, it should not be used as a single agent because resistant mutants frequently form. The responsible mutation may alter the site of action of drug X [i.e., the deoxyribonucleic acid (DNA)-dependent ribonucleic acid (RNA) polymerase]. What is drug X ... 

Sirlin JL, Leoning UE. Nucleolar 4s ribonucleic acid in dipteran salivary glands in the presence of inhibition. Biochem J 1968 109 375-387. 

Deoxyribonucleic acid (DNA) serves as a template for the synthesis of nucleic acids. Ribonucleic acid (RNA) executes protein synthesis and thus permits cell growth. Synthesis of new DNA is a prerequisite for cell division. Substances that inhibit reading of genetic information at the DNA template damage the regulatory center of cell metabolism. The substances listed below are useful as antibacterial drugs because they do not affect human cells. 

Wilkinson DS, Pitot HC. Inhibition of ribosomal ribonucleic acid maturation in Novikoff hepatoma cells by 5-fluorouracil and 5-fluorouridine. J Biol Chem 1973 248 63-68. 

All corticosteroids have the same general mechanism of action they traverse cell membranes and bind to a specific cytoplasmic receptor. The steroid-receptor complex translocates to the cell nucleus, where it attaches to nuclear binding sites and initiates synthesis of messenger ribonucleic acid (mRNA). The novel proteins that are formed may exert a variety of effects on cellular functions. The precise mechanisms whereby the corticosteroids exert their therapeutic benefit in asthma remain unclear, although the benefit is likely to be due to several actions rather than one specific action and is related to their ability to inhibit inflammatory processes. At the molecular level, corticosteroids regulate the transcription of a number of genes, including those for several cytokines. 

Cetkovic-Cvrlje, M., Sandler, S., and Eizirik, D. L. (1993). Nicotinamide and dexa-methasone inhibit interleukin-1-induced nitric oxide production by RINmSF cells without decreasing messenger ribonucleic acid expression for nitric oxide synthase. Endocrinology (Baltimore) 133, 1739-1743. 

Berger, S.L., and C.S. Birkenmeier. 1979. Inhibition of intractable nucleases with ribonucleoside-vanadyl complexes Isolation of messenger ribonucleic acid from resting lymphocytes. Biochemistry 18 5143. 

In vitro genotoxicity studies are summarized in Table 2-17. Eukaryotic cell systems were used for detecting the effects of 2,3,7,8-TCDD exposure on DNA. Exposure to 2,3,7,8-TCDD did not stimulate the unscheduled DNA synthesis in cultural human cells (Loprieno et al. 1982), but inhibited DNA, ribonucleic acid (RNA), and protein synthesis in mouse lymphocytes (Luster et al. 1979) caused gene mutations in mouse lymphoma cells (Rogers et al. 1982) and induced sister chromatid exchanges in Chinese hamster cells (Toth et al. 1984). 

Mauer RA (1982a) Thyroid hormone specifically inhibits prolactin synthesis and decreases prolactin messenger ribonucleic acid levels in cultured pituitary cells. Endocrinology 770 1507-1514. 

Transferrin-containing CD polymer-based nanoparticles were studied as nucleic acid delivery system that can be modified for targeted delivery of small interfering ribonucleic acid (siRNA) to cancer cells. Molecular studies showed that the siRNA CD nanoparticles reduced levels of Ewing s transcript by 80% and inhibited growth of cultured Ewing s tumor cell line. It was also reported that this delivery system indicated a lack of toxicity [39],... 

Symptoms in patients with Wilson s disease usually begin in the second or third decade of life, but may be earlier or later. However, mutations that completely destroy gene function may be associated with onset of liver disease as early as 3 years of age. The initial clinical presentation may be hepatic, with presentation similar to acute hepatitis or to chronic active hepatitis neurological (e.g., clumsiness, dysarthria, ataxia, and tremors) renal (renal tubular acidosis with aminoaciduria) or, less commonly, hematological, with hemolysis secondary to acute release of free copper from tissue and subsequent oxidation of erythrocyte membranes. The hepatic, and possibly CNS, damage may also be secondary to copper-induced oxidative damage to mitochondrial membranes. Hepatic levels of Cp messenger ribonucleic acid (mRNA) are reduced in patients with Wilson s disease, probably secondary to inhibition of transcription by increased intracellular levels of apoCp. ... 

Heme synthesis is controlled by a regulatory negative feedback loop in which heme inhibits the activity of fer-rochelatase and acquisition of iron fi om the transport protein transferrin. The decrease in iron acquisition leads to a decrease in iron uptake into the cell with subsequent decrease in 8-aminolevulinic acid and heme production. Iron deficiency and increased erythropoietin synthesis lead to the combination of the iron regulatory proteins with the iron-responsive elements in the transferrin receptor protein messenger ribonucleic acid (mRNA). This combination in turn leads to protection of the mRNA from degradation with subsequent increased uptake of iron into erythroid cells because of the increased expression of transferrin receptors on the cell membrane. 

Schumm, D. E. and Webb, T. E., Modified messenger ribonucleic acid release from isolated hepatic nuclei after inhibition of polyadenylate formation, Biochem.., 139[1], 191,1974. 

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